This study aimed to determine the specific characterization of regional storage fat in the upper limb as compared to the lower limb of young healthy adults. The regional storage fat and skeletal muscle in upper and lower limbs were obtained by magnetic resonance imaging (MRI) and multifrequency bioelectrical impedance analysis (BIA). For MRI measurements, images at the continuous anatomical cross-sectional areas of subcutaneous adipose tissue and skeletal muscle in the upper arm and thigh were selected for the analysis. Values measured by MRI were larger than those measured by BIA. MRI data showed that the percentage of fat was significantly higher in the upper arm compared to the thigh in both men and women. This study suggests that BIA results in a significantly different estimation of the whole body and limb composition when compared to MRI and that MRI is useful to determine regional specificities in the limb composition. From these quantified evaluation, we found significantly large amount of regional storage fat in upper limbs of young healthy adults, especially women. Modern lifestyles increase the prevalence of metabolic syndrome, which is associated with increased body fat. An increase in adipose tissue and decreased muscle mass causes decreased peripheral uptake of glucose and insulin resistance (Jocken and Blaak The scientific research community has commonly utilized magnetic resonance imaging (MRI) to evaluate lean muscle and adipose tissues due to the accuracy of measuring by contiguous MR slices. MRI offers an accurate and non-invasive means to assess the size and volume of regional muscle and fat  was used. The device can measure segmental impedance at multiple frequencies of five body parts  at six frequencies . While a conventional BIA device needs to adjust the body composition from individual information such as the age and gender, this device can calculate the body component only from the value of the current impedance regardless of race, age and gender  used in our previous study  was calculated as described by McGraw and Wong , rACSAs of subcutaneous fat and skeletal muscle were 0.19 ± 0.05 and 0.60 ± 0.06 cm2/kg in upper arm and 0.48 ± 0.11 and 2.03 ± 0.18 cm2/kg in thigh for men and 0.46 ± 0.08 and 0.41 ± 0.08 cm2/kg in upper arm and 1.29 ± 0.25 and 1.71 ± 0.2 cm2/kg in thigh for women. For both men and women, rACSAs of subcutaneous fat and skeletal muscle in upper arm were significantly lower than those in thigh; however, the amounts of subcutaneous fat relative to skeletal muscle in upper arm were significantly higher than those in thigh.Figure This study was the first to characterize the regional storage fat in the upper and lower limb of young adults as determined by BIA and MRI. According to Bland–Altman analysis, systematic trends were seen between BIA and MRI measurements in both upper limb/upper arm and lower limb/thigh. Indeed, the values measured by the MRI method were larger than those measured by BIA. With regards to men in this study, the BIA data showed that the percentage of fat in the upper limb was not different from that of the lower limb, while for women it was significantly higher than that of the lower limb. However, MRI data showed that the percentage of fat was significantly higher in the upper arm compared to the thigh for both men and women. Additionally, the percentage of fat in women was remarkably higher compared to men in both the upper limb and upper arm as measured by both BIA and MRI. These results revealed that BIA results in a significantly different estimation of the whole body and limb composition when compared to MRI and that the characteristics of the MRI method were useful in determining the regional specificities of the body composition of limbs.Pathophysiological relevance to assess appendicular regional fat and muscle distribution would be revealed in the fact that greater fat mass distributed in appendicular sites, such as lower limbs, appears to be beneficial or protective against cardiovascular disease and/or metabolic risk factors as compared with central obesity (Hu et al. One of the interesting findings of this study was that the percentage of fat was significantly higher in the upper arm compared to the thigh in both men and women. The metabolic responses of the upper and lower limbs are likely to adapt differently through the evolutionary processes of human bipedality. Due to human hands being free from locomotion, the legs engage in motor activities. One of the key factors in the evolution of humans is the improved running economy that allows running longer at less metabolic cost (Bramble and Lieberman It is still unclear why an abundance of fat was stored in the upper arm. Local differences in adipose tissue storage in the upper and lower limbs can suggest regional metabolic responses in the body. It is well known that women have a higher percentage of body fat than men and that they store fat in the hip and thigh regions, as also seen in our results. This might be because the hip and thigh regions in women have a greater number of epinephrine alpha receptors, which inhibit lipolysis Blaak . AdditioThere are several limitations in this study. Small number of subjects might be underpowered for some variables, and the subjects were only selected to young healthy Japanese. Also, confound factors such as daily physical activity levels and genetic background were not considered for body composition. Thus, further study is needed to specifically address the subgroups of age, ethnicity and physical fitness levels with a large sample size. Despite these limitations, our findings may provide an impetus to advance our understanding of physiological and biological significance of specific characterization in fat storage of human body.Our results suggest that BIA results in a significantly different estimation of the whole body and limb composition when compared to MRI and that MRI is useful to determine regional specificities in the limb composition. We found specific characterization in regional storage body fat of young healthy adults: there was a higher percentage of fat in the upper arm compared to the thigh in both men and women, and a higher percentage of fat in the limbs of women compared to men. Further studies are needed to elucidate the physiological and biological significance of these specific compositions.


Transoral robotic surgery (TORS), performed with the da Vinci surgical system (da Vinci), has been classified as a surgical approach for benign and malignant lesions of the oral cavity and laryngopharynx. It provides several unique advantages, which include a three-dimensional magnified view, ability to see and work around curves or angles, and the availability of two or three robotic arms. At present, however, the da Vinci surgical system does not provide haptic feedback. The potential risks specific to the transoral use of the da Vinci include tooth injury, mucosal laceration, ocular injury, and mandibular fracture. To prevent such intra-operative tooth injuries, we created a mouthpiece made of polyethylene terephthalate glycol (PETG) individually shaped for the patient’s teeth. We compared the safety and efficacy of the PETG mouthpiece with those of a conventional mouthpiece made of ethylene–vinyl acetate (EVA). To determine the difference in tooth injury resulting from the two types of mouthpiece, we constructed an experimental system to measure load and strain. We measured the dynamic load and the strain from the rod to the tooth using the PETG and EVA mouthpiece. The rod was pressed against the tooth model outfitted with two types of mouthpiece and the dynamic load was measured with a load cell and the strain with a strain gage. The maximum dynamic load was 1.29 ± 0.03 kgf for the PETG mouthpiece and 2.24 ± 0.05 kgf for the EVA mouthpiece. The load against the tooth was thus less for the EVA mouthpiece. The strain was −166.84 ± 3.94 and 48.24 ± 7.77 με, respectively, while the load direction was parallel to that of the tooth axis for the PETG mouthpiece and perpendicular to the tooth axis for the EVA mouthpiece. The PETG mouthpiece reduced the tooth load compared with the EVA mouthpiece and the load direction was in parallel to the tooth axis. The PETG mouthpiece thus enhances tooth safety for TORS. Robotic surgery using the da Vinci surgical system  has gained popularity as a therapeutic procedure in many surgical fields, especially urological and gastrointestinal . While iTransoral robotic surgery (TORS) with da Vinci surgical system has been used for the removal of pharyngeal and laryngeal cancers with the objective of improving swallowing and other functional as well as esthetic outcomes without worsening survival –9. Sever®), which is currently used in the dental field as the material for mouthpieces for orthodontics [At present, however, the da Vinci surgical system cannot provide haptic feedback. Specific to the transoral use of the da Vinci results are the potential risks of tooth injury, mucosal laceration, ocular injury, and mandibular fracture. The safety record of the da Vinci surgical system in its application to thoracoscopic and laparoscopic surgery establishes a solid background of overall device safety , 11, butodontics –15 and e®) and ethylene–vinyl acetate (EVA) (Erkoflex®) used for conventional mouthpieces by means of assessment procedures such as measurement of friction coefficient, Martens’ hardness test, and Young’s modulus. The second aim was to determine whether the mouthpiece made of PETG is more effective for tooth damage prevention than the conventional mouthpiece made of EVA (Erkoflex®) by measuring load and strain.The first aim of this study was to examine the material properties of PETG , were selected as material for the mouthpieces used in this study  and Young’s modulus (N/mm2) in combination with a Nanoindentation Tester .To measure the material properties of Erkodur (PETG) and Erkoflex (EVA), we used Martens’ hardness test  under the following conditions: velocity 1.00 cm/s; preload 5.00 N, temperature 21.1 °C; humidity 39.00 %; ball diameter 6 mm; ball material SUJ2 (chrome steel).To clarify friction differences due to type of material and determine the effect of friction on load and strain, we measured the friction coefficients of ErkodurThe Erkopress ES 2002 (Erkodent Erich Kopp GmbH) was used to make the mouthpieces of PETG and EVA. The stone tooth model was placed in the device and filled with PETG and EVA with the spacer foil pointing towards the stone tooth model, for thermoforming and trimming. The resultant mouthpieces are shown in Fig. To understand as to what extent differences in the load on the tooth model depend on the mouthpiece material, we measured the dynamic load on the tooth. Dynamic load was defined as the force that is time dependent and quickly changes in magnitude or direction as determined with a load cell system is used. A load cell is a piezoelectric quartz crystal sensor used to measure force in terms of the piezoelectric effect. This effect refers to the linear electromechanical interaction between the mechanical and the electrical state in crystalline materials with no inversion symmetry. Piezoelectricity is the electric charge that accumulates in certain solid materials, such as crystal, in response to applied mechanical stress.The Loadcell 9317B  with the appropriate load amplifier  was used for measuring dynamic load. The data acquisition recorder  used for our study allows for direct and continuous recording with simultaneous graphical visualization of the dynamic load. The data of the dynamic load was recorded 1,000 times per second, previewed from the data recorder and stored on a personal computer.The stone tooth model with the mouthpiece was placed on the instrument table at an incline of 45°. A 12-mm metal rod was pressed against the tooth model outfitted with either of the two types of mouthpiece with a preload of 1 kgf and slid down at a rate of 200 mm/min. The Loadcell was placed under the instrument table and used to measure the dynamic load acting on the stone model. The measurements were performed at room temperature (25 °C) and repeated five times for each mouthpiece. The force was stabilized within 10 s and was set as the maximum force for purposes of this study  with the appropriate load amplifier  was used for measuring strain. For direct and continuous recording with simultaneous graphical visualization of the dynamic load, a data acquisition recorder was used. The data were then displayed by a data recorder  and stored on a personal computer. Since the endoscope and instruments quite often touch the incisors during TORS, the strain gages were applied to the bilateral four central incisors.The stone model with the mouthpiece was placed on the instrument table at an angle of 45°. The 12-mm metal rod was pressed against the tooth model outfitted with either of the two types of mouthpiece with a preload of 1 kgf and slid down at a rate of 200 mm/min. The strain was measured with the strain gauge Fig. . The meat test with a significance level of 5 %.All values are shown as the mean ± SD, and statistical analyses were performed using a standard 2 for PTEG, and 2.039 ± 0.08 N/mm2 for EVA. Martens’ hardness and Young’s modulus for PTEG were significantly higher than for EVA. These findings for Martens’ hardness and Young’s modulus demonstrated that PETG was harder and more rigid than EVA  sign for strain means that the strain gauge is elongated in the vertical direction and the teeth are subjected to lateral pressure. The (−) sign for strain means that the strain gauge is shortened in the parallel direction and teeth are subjected to pressure parallel to the axis.The strain was positive for the EVA mouthpiece and negative for the PETG mouthpiece. The strain direction was parallel with the tooth axis for the PETG mouthpiece and perpendicular to the tooth axis for the EVA mouthpiece Fig.  with a cSeveral studies have reported favorable surgical outcomes and preservation of swallowing function with TORS for oropharyngeal cancer, hypopharyngeal cancer, laryngeal cancer, and tumor of the skull base –9. HowevIn this study, we evaluated the differences between two mouthpieces using a model to determine the degree to which a mouthpiece can prevent risks such as tooth injury resulting from the use of a surgical robot in TORS. The findings of our study suggest that the PETG mouthpiece exerts a smaller load on the tooth load compared with the EVA mouthpiece as a result of a better distribution of the load and rendering the direction of the load parallel to the tooth axis, thus reducing the risk of tooth injury.The PETG mouthpiece exerted a smaller load on the tooth compared with the EVA mouthpiece. In the dental field, PTEG is used for orthodontic mouthpieces. Several studies have reported how much some materials contribute to the strength of the mouthpiece made for tooth remodeling. The findings of these studies demonstrate that orthodontic forces delivered by thermoplastic appliances depend on the material, thickness, and amount of activation –15. HoweThe PETG mouthpiece rendered the load direction parallel to the tooth axis, thus reducing the strain perpendicular to the tooth axis and diminishing the risk of tooth injury. The material analysis performed in this study showed that PETG had a lower friction coefficient compared with EVA, indicating that PTEG is more slippery than EVA. These results show that the PETG mouthpiece distributes the power in the parallel direction and reduces it in the perpendicular direction with the tooth axis. The power perpendicular to the tooth axis involves a much higher risk of loss of teeth than the power parallel to the tooth axis. Our study demonstrated that the PETG mouthpiece reduced the load in parallel with the tooth axis, and shifted the load generated by the external force perpendicular to the tooth axis and thus reduced the risk of loss of teeth.TORS can damage adjacent tissue for the following reasons. First, the da Vinci surgical system in its present form does not provide haptic feedback and thus poses a potential risk of tissue damage resulting from continuous load to the tissue. Second, what is known as the remote center in da Vinci robotic surgery is the fixed point in the space around which the surgical arm and cannula move and helps in maneuvering instruments inside the surgical site while exerting minimal force on the abdominal or thoracic wall. For TORS, the remote center has to be placed outside the mouth to prevent instruments from hitting each arm. Third, Asian patients have smaller mandibular bones and narrower oral and pharyngeal cavities than their Caucasian counterparts so that surgeons find it difficult to secure sufficient working space. When TORS is used for Asian patients, we, therefore, need thinner and firmer mouthpiece for intra-operative observation and correct placement of the endoscope and instruments. The evaluation of the intraoperative safety of TORS and the utility of various mouthpieces is necessary for prevention of injury.In the dental field, PTEG is used for the mouthpiece for orthodontics and is widely distributed and easily obtainable in the market place, making the production of mouthpieces using PTEG very easy –15. The The PETG mouthpiece reduced the load more than the EVA mouthpiece by distributing the load more. Moreover, the PETG mouthpiece rendered the load direction parallel to the tooth axis and thus reduced the risk of tooth injury. The PTEG mouthpiece is effective for TORS because it reduces tooth injury and allows for a relatively large and wide working space. However, further studies are needed to try and find more appropriate materials for mouthpieces in TORS. Furthermore, we hope to evaluate the load and strain when using the PTEG mouthpiece for real human teeth.


Trials evaluating the effects of interventions usually provide little insight into the factors responsible for (lack of) changes in desired outcomes. A process evaluation alongside a trial can shed light on the mechanisms responsible for the outcomes of a trial. The aim of this study was to investigate exposure to and experiences with a computerized decision support system (CDSS) intervention, in order to gain insight into the intervention’s impact and to provide suggestions for improvement.A process evaluation was conducted as part of a large-scale cluster-randomized controlled trial investigating the effects of the CDSS NHGDoc on quality of care. Data on exposure to and experiences with the intervention were collected during the trial period among participants in both the intervention and control group - whenever applicable - by means of the NHGDoc server and an electronic questionnaire. Multiple data were analyzed using descriptive statistics.n = 229) of the included practices generated data for the NHGDoc server and 50 % (n = 116) responded to the questionnaire: both general practitioners  and practice nurses  participated. The actual exposure to the NHGDoc system and specific heart failure module was limited with 52 % of the GPs and 42 % of the PNs reporting to either never or rarely use the system. Overall, users had a positive attitude towards CDSSs. The most perceived barriers to using NHGDoc were a lack of learning capacity of the system, the additional time and work it requires to use the CDSS, irrelevant alerts, too high intensity of alerts and insufficient knowledge regarding the system.Ninety-nine percent  contains supplementary material, which is available to authorized users. Computerized decision support systems (CDSSs) have the potential to improve quality of care , 2. To tIn the Netherlands, a CDSS for primary care - NHGDoc - was developed in 2006, as a collaborative effort between the Dutch college of General Practitioners (NHG)  and ExpeTo evaluate the uptake of NHGDoc and its effectiveness in terms of improving quality of primary care, a large-scale cluster randomised controlled trial (RCT) was conducted within 231 general practices in the Netherlands. More specifically, this two-arm cluster RCT with a follow-up period of 1 year, assessed the effectiveness of NHGDoc with respect to improving the process of medical care (e.g. prescription behavior) as well as patient outcomes , which is described in detail in the Methods section . PrelimiDelivering a complex intervention such as a CDSS in a trial setting does not guarantee that the target group is actually exposed to the intervention as planned. Particularly, in cluster RCTs exposure to the intervention may vary considerably between participating practices . Also, pTherefore, we conducted a process evaluation alongside the trial. The aim of this study was to investigate the exposure to and experiences with our CDSS quality improvement intervention, in order to gain insight into the factors contributing to the intervention’s impact. Results of the process evaluation can provide insight in the feasibility and reproducibility of the intervention  and can NHGDoc is a CDSS integrated within the electronic health record system (EHRS) and based on the NHG guidelines, the prevailing guidelines for general practice in the Netherlands . It provWhen the GP or PN opens a patient file in the EHRS, anonymous patient and performance data are sent to the NHGDoc server. The patient and performance data are compared to the digitized guideline recommendations and in case of a discrepancy between current and advised care, an alert will be sent back to the GP or PN. Also, users have the option to ask or provide feedback from/to ExpertDoc, the organization that has developed and maintains NHGDoc, about the received alert. See  for a dealert settings, users can adjust the preferences of the alerts to match their personal needs. They can choose to switch alerts on and off on demand at several levels: the system, the modules (NHGDoc domains), the types of alerts , and the patients. The reporting settings allow users to request specific reports with respect to the number and types of alerts they have received per domain within a specific period of time . See [Aside from the basic functions , NHGDoc allows the user to adapt the decision support to meet their personal preferences in two different ways. By using ay). See  for a den = approx. 1.100). Our power analysis revealed that we needed to include at least 122 general practices to detect an effect on our main primary outcome measures. A comprehensive recruitment plan was conducted, consisting of a combination of direct invitations via postal mailings as well as emails, combined with announcements of the evaluation study in several relevant Dutch journals, websites, newsletters and through social media  [To evaluate the effects of NHGDoc on quality of care we conducted a cluster randomized controlled trial . All genGeneral practices assigned to the control arm received the regular NHGDoc decision support . These pAlerts on heart failure in terms of registering patient data;Alerts on heart failure in terms of prescribing (or adjusting the dose of) drugs;Alerts on heart failure in terms of (paying attention to) management aspects.See  for a deGeneral practices allocated to the intervention arm received the same decision support modules as the control arm, extended with the NHGDoc module on heart failure . The NHGAt the onset of the trial the NHGDoc heart failure module was activated in the intervention group. Other than that, no activities and time investments were required. General practices and the staff working within these practices were blinded to group allocation. They were even unaware of participating in an intervention trial with a concurrent control group. The trial did not show a significant effect on the identified primary outcome measures  .n = 115) and control arm (n = 116) - whenever applicable - in two different ways: by collecting data from the NHGDoc server and by conducting a questionnaire. Informed written consent was obtained from all practices: each general practice filled out an online registration form in which they agreed with the design of the study and the use of NHGDoc server data as described on the website  and gave consent on behalf of all practice staff (GPs and PNs). Responding to the questionnaire was voluntary and again information was provided on handling the data in terms of confidentiality and anonymity.The need for ethical approval for the NHGDoc evaluation study was waived by the research ethics committee of the Radboud university medical center. Data for the process evaluation were collected among all participating practices in both the intervention , switched off NHGDoc modules including heart failure (intervention group only), opening of alerts including for heart failure patients (intervention group only). Data were collected continuously during the trial and were sent to our research institute  on a monthly base [We extracted the following data from the NHGDoc server to measure hly base .n = 231). From each general practice we invited one GP and one PN (if applicable) to fill out the questionnaire. Aside from demographic and professional characteristics , exposure to and experiences with the CDSS intervention were measured.At the end of the trial an electronic questionnaire .Experiences with the intervention were measured in two different ways: by measuring attitudes towards CDSSs in general and by measuring perceived barriers and suggested interventions to using NHGDoc. Prior to developing the questionnaire, we conducted a qualitative focus group study to identify the range of barriers that GPs and PNs perceive in using NHGDoc or similar CDSSs in practice. Three focus group sessions were conducted in which 24 primary care practitioners (PCPs) participated , varying from 7 to 9 per session. In each focus group, barriers to using CDSSs were discussed using a semi-structured literature-based topic list. Two researchers independently performed thematic content analysis using the software program Atlas.ti 7.0.This resulted in a framework of barriers, which is described elsewhere in detail . In geneEight statements were included to measure the attitudes towards CDSSs in general, based on literature on attitudes towards using clinical practice guidelines , 18, comKnowledge-related barriers were measured with six statements referring to knowledge about the (specific functions of the) system (e.g. ‘I am aware of the option to ask for or to provide feedback in NHGDoc’).Barriers related to the evaluation of the features of the CDSS were measured with 11 statements .External barriers interacting with the CDSS were measured with 6 statements (e.g. ‘Using NHGDoc has a negative effect on patient-doctor communication’).To measure the perceived barriers three groups of barriers were included, based on the framework that emerged from the focus group study .KnowledgThe knowledge-related barriers were scored on a 2-point scale (yes/no). All other statements were rated a 5-point scale (ranging from 1. strongly disagree to 5. strongly agree), with the option ‘not applicable’ (6.) added to the response scale. Suggested interventions to improve CDSS usage were also discussed and will be described elsewhere.Finally, the intended ‘blinding’ in terms of the topic of the intervention was checked among the participants by formulating the following open question ‘Do you have any idea on which clinical topic this study focused on?’.Data from the NHGDoc server measuring exposure to NHGDoc were analyzed using descriptive statistics. To analyze exposure as measured by the questionnaire we categorized the scores 1 and 2 to indicate a low level of use, we coded 3 as a moderate level of use, and combined the scores 4 and 5 to reflect an intermediate to high level of use.To analyze the attitudes towards CDSSs in general we categorized the scores 4 and 5 (agree/strongly agree) indicating agreement; the scores 3 to refer to a neutral attitude, and the scores 1 and 2 (strongly disagree/disagree) to indicate disagreement.The knowledge-related barriers were calculated by the percentage of respondents that indicated not to be aware of NHGDoc or its specific functions (score 1). For the second and third group of barriers  the barrier statements that were stated positively rather than negatively, were first recoded, so that a higher score indicated a higher level of perceived barriers. Next, the scores 4 and 5 were combined to indicate the percentage users that indicate a barrier to be applicable.The 231 participating practices were an acceptable reflection of the population of Dutch GP practices, with solo practices only being slightly overrepresented .Almost all recruited practices (229/231 = 99 %) generated data into the NHGDoc server database; two were eliminated from the trial due to technical problems. Because of this high rate, the background characteristics are comparable to the study population.Of the 231 practices 50 % responded to the survey (see Table From the group of responding GPs (49 %) relatively more men (69 %) were included compared to our total study population (69 vs. 53 %). The majority of the participating GPs were aged between 55 and 64 years (46 %) (no comparison possible). Ninety-eight percent of the responding PNs (37 %) were women (98 %), a little more compared to our study population (93 %). Most of them were aged between 45 and 54 years of age (no comparison possible).Figure The NHGDoc alerts concerning heart failure patients were opened in only 0.24 % of the cases. This was 0.35 % for the total patient population. No trend towards increased use was detected during the trial period.Data from the NHGDoc server also revealed that less than 2 % of the participating primary care providers used the personalization functions of NHGDoc to switch off one or more NHGDoc domains. With respect to the specific Heart failure domain this percentage was less than 1 %.Table From the basic functions half of the GPs (51 %) and 40 % of the PNs reported never or rarely to use the alert functions. Thirty-eight percent of both groups indicated to use the alert functions sometimes. The feedback function demonstrated a lower level of use with 88 % of the GPs and 86 % of the GPs never or rarely using it. Less than 2 % of both groups indicated to use the feedback option often or all the time.With respect to the personalization functions of My NHGDoc, the majority of both GPs (72 %) and PNs (65 %) reported to never or rarely use this function. Relatively more PNs as compared to GPs used it often or all the time (18 vs. 5 %). Eighty-two percent of the target group never or rarely used the alert settings; for the reporting settings this figure was 85 %.As can be seen in Fig. Sixty percent of the GPs and 25 % of the PNs indicated that the use of CDSSs is difficult to integrate in daily practice. About a third of both groups (36 % of GPs and 31 % of PNs) was afraid that using CDSSs leads to ‘cookbook medicine’. One fifth of both groups (21 and 19 %) reported to lack knowledge and skills to properly use CDSSs. Thirteen percent of the GPs and 6 % of the PNs indicated to have overall resistance to working with CDSSs.Table As can be seen in Table functionality was considered relevant. In both groups a lack of learning capacity of the system (80 and 75 %), a too high intensity of the alerts (40 and 32 %) and a lack of responsiveness of the system (33 and 38 %) were often perceived as barriers. From the subgroup source and content of the CDSS the relevance of the alert content for individual users was often perceived as a barrier in both groups (58 and 62 %).From the group of barriers related to the evaluation of the features of the CDSS, particularly the subgroup environmental factors were often perceived as barriers. Sixty percent of the GPs indicated the limited time available to be a barrier, whereas only 16 % of the PNs considered this to be a barrier. Also, 60 % of GPs reported that using the CDSS required too much extra work, as compared to 27 % of the PNs. From the patient-related factors, particularly a negative effect on patient communication was considered as a barrier by 26 % of the GPs and 22 % of the PNs.From the group of external barriers interacting with the CDSS, particularly Finally, the blinding check showed that none of the respondents was aware of the fact that heart failure was the focus of the intervention.This process evaluation revealed that the target group was not exposed to the intervention as planned as the use of NHGDoc and its specific heart failure module was limited. Although  users had a positive attitude towards CDSSs in general, several barriers to using NHGDoc could have hampered the uptake and effectiveness of the intervention. The large share of users that was insufficiently aware of the functions of NHGDoc, as well as the proportion that finds the decision support not useful or not relevant and difficult to integrate into daily practice, indicates that both the CDSS intervention itself as well as its implementation could be improved. These findings are in line with the lack of changes in outcomes of the CDSS intervention.The actual exposure to NHGDoc and the heart failure module was low, with about half of the  users reporting to either never or rarely use the system and less than 1 % opening alerts. Despite a few negative spikes in NHGDoc activity, which are presumably related to vacation periods of the staff, the activity was quite stable throughout the trial and technical problems did not seem to be a major issue. Also, the low level of exposure to NHGDoc was not related to users deliberately switching of one or more modules of NHGDoc. In interpreting the number of alerts in our study, it is important to realize that the different modules do not result in different alerts each. Rather, the advices are combined in one alert, consisting of an alert window with different tab pages for all relevant domains. Moreover, prior studies have also found high levels of ignoring of alerts among their users –22. NoneAlthough the target group of  users had a positive attitude towards CDSSs in general, several barriers were reported that could have affected the uptake and effectiveness of the intervention. The most perceived barriers to using NHGDoc were a lack of learning capacity of the system, the limited time available and the additional work it requires using the CDSS, irrelevant alerts, too high intensity of alerts and insufficient knowledge regarding the system. These findings are consistent with our focus group study and confirm that barriers to using NHGDoc were found within all three main groups of barriers in our previously developed framework of barriers to using CDSSs .With respect to the knowledge-related barriers we found that the target group was insufficiently aware of NHGDoc and its functions, particularly the advanced personalization functions. At the onset of the trial the NHGDoc module on heart failure was activated in the intervention practices, without any further instructions. We deliberately chose for this method, as we aimed at both practitioners and patients being blinded to group allocation, which is important in protecting against bias , 24. MorAside from improving the implementation of CDSS interventions among the target group, our results indicate that in our study the CDSS intervention itself also exhibits some shortcomings, often referred to as the ‘intervention failure’ , 26. WitExternal barriers interacting with the CDSS were also experienced as barriers which has been found in other studies as well –32. As mOne of the limitations of this study is the seemingly late conduction of this barrier study. However, it should be noted that the NHGDoc system already existed for 5 years at the start of the trial and several small user-satisfaction studies had been conducted among users. Moreover, implementing (CDSS) interventions at a larger scale outside the academic setting, seems to elicit different types of barriers, that cannot be identified in a preceding barrier study among early adopters , 33. ImpA major strength of this study is that we collected data using several methods and targeting different types of PCPs. Moreover, our study demonstrates high content validity as the questionnaire used in this study is based on qualitative study findings from the same group . HoweverFew thorough process evaluations have been conducted in the field of CDSSs, particularly regarding multiple-domain covering CDSSs implemented at a larger scale. This study used multiple methods, targeting different types of PCPs, and with data collected within the intervention group as well as the control group. Future studies on CDSSs may benefit from thorough evaluations like this one to determine the factors that facilitate or hinder the implementation. Whereas some of the suggested strategies, such as increasing user flexibility, may particularly be helpful in implementing multiple-domain covering CDSSs at a large scale, other strategies, such as involving the end-users in designing the CDSS, also apply to the more common CDSS aimed at a limited number of decision points.This process evaluation has identified some factors that might be responsible for the lack of changes in outcomes of the CDSS intervention, as well as useful strategies to improve its implementation. Results indicate that both the CDSS intervention itself as well as its implementation could be improved. Although users are generally positive about CDSSs, a large share of them is insufficiently aware of the functions of NHGDoc and finds the decision support not always useful or relevant and difficult to integrate into daily practice. In designing (similar) CDSS interventions we suggest to more intensely involve the end-users and increase the system’s flexibility and learning capacity. To improve implementation a proper introduction of a CDSS among its target group including adequate training is advocated.


The immunotherapy using dendritic cells (DCs) against different varieties of cancer is an approach that has been previously explored which induces a specific immune response. This work presents a mathematical model of DCs immunotherapy for melanoma in mice based on work by Experimental Immunotherapy Laboratory of the Medicine Faculty in the Universidad Autonoma de Mexico (UNAM).β cytokine (TGF−β). The model is validated comparing the computer simulation results with biological trial results of the immunotherapy developed by the research group of UNAM.The model is a five delay differential equation (DDEs) which represents a simplified view of the immunotherapy mechanisms. The mathematical model takes into account the interactions between tumor cells, dendritic cells, naive cytotoxic T lymphocytes cells (inactivated cytotoxic cells), effector cells (cytotoxic T activated cytotoxic cells) and transforming growth factor %. This allowed us to use the model as a framework to test hypothetical treatments. The numerical simulations suggest that by using more doses of DCs and changing the infusion time, the tumor growth decays compared with the current immunotherapy. In addition, a local sensitivity analysis is performed; the results show that the delay in time “ τ”, the maximal growth rate of tumor “r” and the maximal efficiency of tumor cytotoxic cells rate “aT” are the most sensitive model parameters.The results of the growth of tumor cells obtained by the control immunotherapy simulation show a similar amount of tumor cell population than the biological data of the control immunotherapy. Moreover, comparing the increase of tumor cells obtained from the immunotherapy simulation and the biological data of the immunotherapy applied by the UNAM researchers obtained errors of approximately 10 By using this mathematical model it is possible to simulate the growth of the tumor cells with or without immunotherapy using the infusion protocol of the UNAM researchers, to obtain a good approximation of the biological trials data.It is worth mentioning that by manipulating the different parameters of the model the effectiveness of the immunotherapy may increase. This last suggests that different protocols could be implemented by the Immunotherapy Laboratory of UNAM in order to improve their results.The online version of this article (doi:10.1186/s12976-015-0007-0) contains supplementary material, which is available to authorized users. Melanoma is a dangerous form of skin cancer and its prevalence is increasing at a dramatic rate worldwide , 2. In tThe immunotherapy used the tumor cell property to express antigens than can be recognized by the immune system and became targets of the tumor-specific T cells , 7, 8. TCD4+ and CD8+ T lymphocytes). These encounters activated CD8+ lymphocytes proliferating and differentiating into CTLs leaving the lymphoid organs where they were generated and migrate to eliminate the tumor cells [The antigen-specific immunotherapy with DCs uses the capacity of present antigens and activates the immune specific response of DCs. Immature DCs in a steady state located in epithelial and connective tissues have the ability to detect and capture antigens that are found. After capturing the tumor antigens, these mature and transport the antigen to lymph nodes where they present the tumor antigen to naive T lymphocyte cells  [Tumor cells use the mechanisms of host defense to promote tumor progression, invasion, and dissemination to distant sites. One of these mechanisms is by secreting lecules) , 12.in vitro and then injected back into the patient. The immunotherapy is specific because it only eliminates tumor cells and does not injure most normal cells in patient [In this immunotherapy, the DCs taken from the patient were incubated with tumor antigens and adjuvants  patient .% over a 36 month period [% over 34 days [There is hope that one of these immunotherapies, the Sipuleucel-T treatment shows that the personalized treatment with antigen-presenting cells (APCs) could be efficient to extend the life of people suffering from prostate cancer by 31.7 h period . For tha 34 days .MAGE−AX peptide which stimulate the immune response before being injected into the mice. The biological treatment efficiency is measured taking into consideration the tumor diameters, cytokines modulation (IL-2 and IL-10), the expression of major histocompatibility complex molecules (MHC) and the survival of the mice.The UNAM researchers incubate the DCs derived from mice bone marrow with granulocyte-macrophage colony stimulating factor (GM-CFS) to mature the cells and antigen However, the tumor has not been eradicated and there are still many unanswered questions about how the immune system interacts with the tumor cells, and which components of the immune system play significant roles in responding to immunotherapy. Actually, they used only one infusion protocol  between the real data and the numerical simulation is obtained, taking into account the measurement time made by the UNAM researchers (the 7th day after melanoma cell induction and every two days after the 10th day for a period of 700 hours). The population of the tumor cells in the melanoma tumor was calculated from the diameters average of tumor melanoma assuming a spheric form .Figure 6 DCs activated with MAGE-AX, infused every 168 hours during three weeks  and we change the amount of DCs injected per dose. The numerical results are shown in Table To measure the efficiency of the proposed protocol, the average reduction of tumor cells (in percentage terms) is computed comparing the tumor cell population simulated without treatment and the tumor cell population simulated with the hypothetical treatment measured at the same time (the 7th day after beginning the simulation and every two days after the 10th day for a period of 1000 hours).3 DCs every 7 days during 3 weeks (dotted line) it can be observed that the growth of the tumor does not suffer any change and continues growing, demonstrating that this amount is not sufficient to eliminate or to detain the growth of the tumor (thick line) in the simulation.Figures 8 DCs injected every 7 days during 3 weeks; the simulation shows how the tumor cells population declines dramatically after 700 hours.On the other hand, Fig. 6 DCs per dose, Protocol 1), to show the influence of the number of infusions in the treatment. As in the other experiments, the efficiency of the hypothetical protocol is measured using the average reduction of tumor cells. The numerical results are shown in Table It is proposed to modify the infusion interval time of the DCs, conserving the same number of DCs used in the biological experiment .In order to know which parameters affect the model outcome a local parametric sensitivity analysis (LPSA) was made , 19. Theτ” has the bigger percentage change in the amount of tumor cells at the end of the model simulation with an interval of change between −76.64 % and 45.33 %, followed by the tumor growth rate “r” and the maximal efficiency of cytotoxic cells “aT”.Figure % between the results obtained from the model simulation and real immunotherapy data from the biological trials developed by the UNAM researchers. In spite of only taking into account the interactions between the tumor cells, the dendritic cells, the CTLs activated/inactivated and the TGB−β cytokine the approximation could be considered successful.The mathematical model of 5 DDEs presented is capable of simulating the tumor cells growth with a NRMSE 10 The validation of the model allows to test different hypothetical immunotherapy protocol changing the number of infusions or varying the amount of DCs injected.6 DCs are injected every 96 hours during 3 weeks, the growth of the tumor is less than the current immunotherapy protocol and as a result the mice could live longer. This protocol is viable biologically and experimentally, which could be tested by the research group of UNAM.As a result of these trials, it is observed that if 4 doses of 107 dendritic cells the tumor is eradicated. Moreover, increasing this amount the DCs in vitro is not experimentally viable at the moment for the research group of UNAM due to laboratory limitations.By varying the number of DCs injected from the protocol proposed in Table % activated and stimulated the reproduction of the CTLs. By performing this experiment, the results show that if more that 80 % of DCs arrive at the lymph nodes, the tumor is eradicated. This suggests that if the immunotherapy is improved, making more tumor cells reach the lymph nodes, the tumor could be erradicated.In case of variation in the percentage of DCs that induce the immune response,the objective is to know whether the number of DCs injected affects the therapy efficiency. The validation model takes into account that not all DCs become effective, around 50 β” cytokine [β” can give better results than the current therapy used.Currently, some immunotherapies have been including inhibition of “TGF- cytokine , for theBy performing the sensitivity analysis of the parameter model it was observed that the delay in the time is the most sensitive parameter. Observing in the biological experiment results the main inmunotherapy response is given on the 30th day after injecting DCs into the mice and not on the day when they were injected. The reason for this delay is not clear for the UNAM researchers but it is proposed in the model that the activation and the proliferation of the CTLs was before the CTLs could eliminate the tumor cells this represents the time delay used in the model. The rate of tumor growth is another sensitive parameter and is influenced by the type of cancer (in this case skin melanoma).On the other hand, the cytotoxity of the CTLs represent the capacity of the CTLs to eliminate the tumor cells and its other sensitivity parameter. One factor more in the sensitivity of the model is the efficiency of the immunotherapy that means the number of dendritic cells that arrive at the lymph nodes to activate and reproduce the CTLs. This efficiency is related with the treatments that the DCs receive before being injected into the mice, and they are not considered in this model for the moment.For now there is no biological proof to verify the hypothetical treatment. However, the objective of the model is to present a guide for a possible therapy with a greater possibility of success. Future work concerns amplifying the model including more population cells, cytokines or the treatment of DCs before beginning the immunotherapy.The model represents a simple view of some mechanisms that occur between the immune system and the immunotherapy with DCs for the melanoma in mice. Even when is only taking into account 5 interactions between the immune cells, tumor cells and one cytokine, the model reproduces in an adequate form the behaviour observed in the experimental biological trials and its validation gives the possibility to prove different hypothetical protocols.β” cytokine or increasing the percentage of DCs that arrive to the lymph nodes.Using the model as a framework the numerical results show that immunotherapy used in the biological experiments could be improve manipulating the number of DCs infused, changing the intervals of injection, changing the effect of “TGF- τ”, the maximal growth rate of the tumor “r” and maximal efficiency of cytotoxic cell parameter “ aT” plays a significant role in increasing the effectiveness of the immunotherapy. These results give other hints of how the immunotherapy could be improved.Moreover, the model is used to analyse the consequences of manipulating their parameters. It is found that the delay in the time “ The the mathematical model can be used as a guide to improve the immunotherapy and thus minimize the costs in time and money to test new protocols. Eventually, the UNAM researchers could have a better possibility of success for a new protocol.Finally, during the test phase it was observed that the model could be improved by increasing the number of key elements for example the CD4+ helper T lymphocyte response and the B cell response that are related with the production of antibodies with affinity to recognize the antigen melanoma, the secretion of IL-2 cytokine that acts on the activated lymphocytes and stimulates their proliferation, the major histocompatibility complex (MHC) molecules, which are expressed on the surface of the dendritic cells and stimulate the response of the T cells or include a small pre-treatment DCs model in the five DDEs of the model.C57BL/6 between 6 and 8 weeks of age maintained in the animal facilities of the Medicine Faculty of UNAM. DCs used in the immunotherapy are taken from mice bone marrow and incubated in vitro with MG-CSF cytokine to differentiate the DCs and MAGE-AX (25μ g/ml) antigen to stimulate the immune response. On the other hand, the formation of melanomas is induced in mice after infusion 6×104 cell B16/F10 line. Immunotherapy begins in the 10 mice one week latter after the tumor is induced; vaccine protocol uses 106 dendritic cells per dose infused once a week for 3 weeks  and allowing the tumor growth without immunotherapy. The efficiency of the biological treatment was measured by comparing tumor diameters, the IL−2 and IL−10 cytokines modulation, the expression of MHC molecules and the survival rate of mice receiving the inmunotherapy.The immunotherapy control was made injecting 6×10The tumor diameter was measured on day 7 once the tumor cells had been injected. Afterwards, they were measure every two days consecutively after day 10 until the mice died or 5 weeks after the first dose of the DCs had been injected.cm. Injecting the DCs pretreated with MAGE−AX peptide before the immunotherapy, the outcome showed that some mice lived until the 40th day with an average diameter of 1.5cm.The results demonstrated that the mice without immunotherapy lived for 28 days, having an average diameter of 4.3% of total DCs injected per dose activated the immune response.Considering the investigation observation of the research group of UNAM that not all of DCs could arrive at the lymph nodes to activate the cytotoxic cells, it takes in consideration that only the 50 6 dendritic cell activated with MAGE-AX, infused every 168 hours during four weeks.The proposed model gives a simplified view of the mechanism between the immune system and the immunotherapy developed by the research group at the Medicine Faculty of UNAM, where melanoma in mice is treated with a DCs immunotherapy. The immunotherapy protocol Table  applies ex vivo active alloreactive cytotoxic T-lymphocytes (aCT) treatment to boost the immune response.The mathematical model is based on the mathematical model proposed by Kronik et al.  which deT”, dendritic cells “D”, effector and naive cytotoxic T cells “ Ca, Ci” and the cytokine transforming growth factor β “ Fβ”; this cytokine reduces the efficiency of the immunotherapy, as is shown in [β (TGF- β). A delay in the time, “ τ” is included in the model to describe the time of activation of dendritic cells.DDEs system is proposed taking into account the interactions between the tumor cells population “shown in . MoreoveSome parameters are obtained from the bibliography, and others are calculated using the model of DDEs, adjusting their values to biological treatments results, trying to minimize the difference of the numerical data with the experimental data, see the supplementary material for a complete explanation.T”, Gompertz growth law was considered  first term on the right hand side (RHS) of Eq. r” represents the maximal tumor growth rate and the parameter “K” its carrying capacity (the limit of the maximum population size of the tumor cells that the environment can sustain). Notice that the number of cells in a mouse is significantly lower than “K”, we consider Gompertz growth if T<1.6×1010 and the experiments stop if T=1.6×1010. It is worth to mention, that at if T=1.6×10 the mice died.To study the growth of tumor cells population “Ca” \docD”. The initial number of dendritic cells is consider, d0 which decay at constant rate μD, then, for n<168 the number of dendritic cells is given bytn=n·168 for n=1⋯3, 106 dendritic cells are injected into the mouse, so, the number of dendritic cells of the immunotherapy is given byEquation ef represents the percentage of the DCs which arrive the lymph nodes to begin the immune response. Notice that the evolution of dendritic cells inside the intervals (168(n−1),168n) for n=1⋯3 is given byWhere, Ca”, is described in Eq. CD8+, expansion of the CTLs activated and a natural death of CTLs activated.The dynamic of CTLs activated, “ ra, The encounter between the inactivated cytotoxic cells and DCs occurs at the time of t−τ. On the other hand, the survival probability of the inactive cytotoxic cells during the delay time is considered by the term θD”.The first term on the right side of the equation represents the cytotoxic cells activation. It is considered that the contact between the DCs and the inactive cytotoxic cells produce the activation of these. It is proposed that the activation is made before the death of the tumor cells and gives a rate re, given for the contact between the DCs and the activated cytotoxic cells (described as a saturation function of type Michaelis-Menten). In the same way as the cytotoxic activation cells, the expansion is given before the death of the tumor cells and occurs at the contact time of t−τ between the DCs and the activated cytotoxic cells. The probability of the activated cytotoxic cell survival is consider during the time delay in term The second term on the right side of the equation represents the expansion of the activated cytotoxic cells. This expansion shows a rate of The natural death of the activated cytotoxic cells is included in the last term of the equation Ci”. The first term on the right hand side of the equation is equal to the first term of the equation t−τ.Equation Due to the mice immune system not presenting any response before being injected by immunotherapy, it is not considered a term that produces new inactivated cytotoxic cells. The model only takes into account a base amount of inactivate cytotoxic cells that is introduced into the model as an initial condition (see Additional file Ci” efficiency on “D” population is represented by Michaelis constant “ θD”.The effect of dendritic cells in the CTLs activation is supposed following a Michaelis-Menten dynamic and the dependence of “ A constant death rate “β, “ Fβ”. The term “ aT,β” represents the production rate per tumor cell. It is proportional to the number of tumor cells, “T”. The last term of the equation is a natural degradation rate “ μβ” of the TGF- β.Equation in vivo experimental results of immunotherapy developed by the research group. The additional material presents the references used to obtain the model parameters (see Additional file The model is implemented using a 4th order Runge Kutta method with the integration step of 1 hour , 23. Somr” and the maximal population size of the tumor cells that the environment can sustain “K” using least square method and setting an initial population size of tumor cells at 6∗104 according the immunotherapy protocol applied by the research group of UNAM (Table The experiment data is used to calculate the value of maximal growth rate of tumor, “aT”, the activation rate of CTLs “ ra”, the expansion rate of activated CTLs “ re” and the delay in the time “ τ” are calculated after an exhaustive search minimizing the difference between the numerical results and the experimental data, the additional material shows more detail (see Additional file The maximal efficiency of cytotoxic cells “


A method is proposed for measuring the fluorescence quantum yield (QY) using a commercial spectrophotometer with a 150 mm integrating sphere (IS) detector. The IS detector is equipped with an internal cuvette holder so that absorbance measurements can be performed with the cuvette inside the IS. In addition, the spectrophotometer has a cuvette holder outside the IS for performing conventional absorbance measurements. It is shown that the fluorescence quantum yield can be obtained from a combination of absorbance measurements of the buffer and the analyte solution inside and outside the IS detector. Due to the simultaneous detection of incident and fluorescent photons, the absorbance measurements inside the IS need to be adjusted for the wavelength dependence of the photomultiplier detector and the wavelength dependence of the IS magnification factor. An estimate of the fluorescence emission spectrum is needed for proper application of the wavelength-dependent adjustments. Results are presented for fluorescein, quinine sulfate, myoglobin, rhodamine B and erythrosin B. The QY of fluorescein in 0.1 mol/L NaOH was determined as 0.90±0.02 where the uncertainty is equal to the standard deviation of three independent measurements. The method provides a convenient and rapid estimate of the fluorescence quantum yield. Refinements of the measurement model and the characteristics of the IS detector can in principle yield an accurate value of the absolute fluorescence quantum yield. Integrating spheres (IS) have been used extensively for measuring optical properties of surfaces, films and light sources. The light from a source placed at the center of the sphere is reflected many times by the surface of the IS. By the time the light hits the detector  much of the original emission anisotropy has been eliminated so that the detector gives a good measure of the total emitted radiant power. The detailed description of the reflection process inside the IS can be found in the literature ,2. The IThe proposed method for measuring the fluorescence quantum yield utilizes a commercial spectrophotometer with an integrating sphere (IS) detector. Two measurements of absorbance have to be carried out on the same cuvette. One measurement is performed with the cuvette placed outside the IS, and the second measurement with the cuvette inside the IS. For clarity, the measurement will be described with a specific instrument—the Perkin Elmer Lambda 850i (W-Watts), enters the IS through a sample aperture of area Ai (m2), passes through a cuvette, and hits the wall of the IS. A reference flux, Φr (W), enters the IS through a reference aperture of area Ar (m2) and hits the IS wall without passing through the cuvette. Mref represents the magnification of the incident reference flux due to the many reflections on the IS wall. Neglecting the presence of the cuvette holder and the baffle, the ideal IS behavior leads to the following expression for the magnification Mref = ρ(1 − f)/(1 − ρ(1 − f)) [f is defined as the ratio of areas given by f = (Ai + Ar + Ad)/AS where Ad and AS are the areas of the detector aperture and total sphere surface respectively. The reflectance of the material lining the surface of the IS is given by ρ. The detector is mounted flush with the surface of the IS. Therefore the detector response will be proportional to the average flux incident per unit surface area of the IS multiplied by the detector area. Explicitly, the detector signal, Dref, will be given by R(λ) is the radiant sensitivity of the photomultiplier cathode. The ratio of the detector area to the area of the entire IS is a constant which can be combined with the radiant sensitivity to give overall detection efficiency E(λ). It will be assumed that the dependence of the detection efficiency on wavelength comes from the radiant sensitivity of the photomultiplier cathode. An excellent description of various biases inherent in IS measurements has been presented by Hanssen and Snail [An incident flux, Φ(1 − f)) . The connd Snail .i, entering the IS through the sample port and hitting the cuvette filled with a fluorescing solution. As shown in t (W). Another flux will arise due to scattering from the cuvette walls. The scattering flux will be called Φs (W). Finally there will be a flux associated with the radiative decay of excited molecules. The fluorescence flux will be emitted over an extended range of wavelengths and will be called Φf (W/nm). The scattered and fluorescence fluxes are emitted from the cuvette in all directions. The cuvette holder inside the IS has a bottom coated with the same material as the surface of the IS. This bottom serves as a “baffle” preventing the detector from seeing the direct fluorescence and scattered fluxes. Therefore the fluorescence and scattered fluxes arriving at the detector will be the average fluxes obtained after many reflections. However, the fluorescence flux is spread over the wavelength region associated with the fluorescence emission spectrum and therefore it has different detection efficiency from that of the scattered flux. All of these considerations lead to the following expression for the detected signal, Dsample, when the flux Φi enters the IS through the sample port.Consider the detector response for the case of the flux, ΦMinc is the magnification factor for flux transmitted through the cuvette. The transmitted flux hits the same spot on the surface of the IS as the incident flux, and therefore it is likely that it evolves identically to the incident flux in the absence of a cuvette. Mcur is the mul tiplication factor for flux originating in the cuvette. It is assumed that the fluorescence and scattered fluxes evolve in similar fashion. i, and the fluxes exiting the cuvette will be determined by the cuvette and its contents as discussed below. Finally, if there is no cuvette in the sample holder, then Dsample and Dref should in principle be equal because the incident flux is not modified. The autozero function of the Lambda 850 corrects for small differences in IS response between the reference beam and the unobstructed sample beam. MincΦi = MrefΦr. Subsequent to the autozero, and the insertion of a cuvette into the sample holder, the Lambda 850 measures the average fluxes incident on the IS surface and reports the absorbance, A, calculated from the relation A = −log(Dsample/Dref). This procedure is carried out irrespective of whether the cuvette is placed inside or outside the IS. In what follows we will use A to extract the fluorescence quantum yield. We start with the discussion of traditional absorbance measurement with the cuvette mounted in a holder outside the IS.a = σN, is expressed as a product of the absorption cross section, σ, in units of cm2 and the molecular concentration, N, in units of cm–3. The fluorescence flux is modeled as originating from the absorbed flux with a parameter called the quantum yield (QY) which gives the fraction of absorbed photons that appear as fluorescence photons. For the case of a cuvette outside the IS detector, we assume that the amount of fluorescence flux that reaches the detector is negligible. This assumption is plausible since the fluorescence is emitted in all directions and only a negligible part will be accepted by the detector aperture. Let r and t be the reflection and transmission coefficients of the two cuvette walls. The effect of the first cuvette wall is represented by a change in the incident flux to tΦi = 10logtΦi. The differential equation can be solved to find the flux after the beam has traversed the fluid inside the cuvette. The result is tΦie−al = tΦi10−0.434al where l is the path length which will be set to 1 cm. The second cuvette wall introduces another transmission coefficient. Finally the transmitted flux can be written in terms of the incident flux and the properties of the cuvette to give the ratio of expected signals shown in A. The value of A presented by the instrument can be compared directly to the exponent given by the model in t and a, the contribution from the multiple reflections is less than 0.0005 absorbance units.The three terms in The measurement of absorbance with the cuvette inside the IS is a very different process since the measured flux includes the transmitted flux as well as fluorescence and scattered fluxes. The fluxes are shown in It will be assumed that the incident flux reflected from the first and second cuvette walls exits the IS through the entrance aperture. The design of the IS and the shape of the entrance beam are optimized to insure this event. The sample beam entering the IS detector is focused on the back surface of the IS. This means that the beams reflected from the cuvette walls (located in the center of the IS) are focused on the entrance aperture of the IS detector. Therefore the cross sectional area of the reflected beams at the entrance aperture of the IS will be smaller than the cross section of the incident beam, and therefore all of the reflected beams should exit the IS detector.x of the material in the cuvette can be modeled as i (W) represent the energy flux incident on a cuvette. Then the transmitted flux is given by 10−0.434aΦit. The energy absorbed in the cuvette is given by (1 − 10−0.434a)Φit. In practice the incident light is reasonably monochromatic. Therefore it is possible to calculate the total number of incident photons absorbed by the material in the cuvette as (1 − 10−0.434a)Φit/hfi where hfi is the energy of a single incident photon. The quantum yield, QY, gives the fraction of photons emitted for a given number of absorbed photons. Therefore the number of emitted photons is given by QY(1 − 10−0.434a)Φit/hfi. The emitted photons are usually distributed over a range of wavelengths. The quantity s(λf) (nm−1) gives the fraction per unit wavelength of the total emitted photons with a wavelength λf. Therefore the number of photons emitted per unit wavelength is given by QY(1 − 10−0.434a)tΦis(λf)/hfi. The energy emitted per unit wavelength is obtained by multiplying the number of photons by the energy of a single emitted photon. The final result for the fluorescence flux per unit wavelength (W/nm) is given byl, was set to 1 cm. The increase in the fluorescence flux due to multiple reflections inside the cuvette can be modeled by a beam propagating perpendicularly to the cuvette walls. Multiple reflections result in an increase of about 4 % in the fluorescence flux. This effect will not be included in this initial presentation. The fluorescence flux may be reduced by self absorption since most fluorophores exhibit a slight overlap between absorption and emission bands. This effect will also be neglected. The scattered flux from the cuvette walls will be modeled as a constant fraction of the incident flux, ΦS = rSΦi. The ratio of the detector responses when the beam enters through the sample port and when it enters through the reference port can be modeled by inserting the values of the specific fluxes into The fluorescence flux from a slab of thickness dTogether with The notation in t = 1, rs = 0, δM = 1), and constant detection efficiencies over all wavelengths. In this ideal case, It is useful to note that The expression E(λ)·Minc(λ)/(〈EM〉 ·λ).In the following, we perform some measurements and demonstrate that the analysis of the data with We describe the application of t. The transmission coefficient is a product of two transmission coefficients associated with the air-fused silica and fused silica-water interfaces. These two transmission coefficients are evaluated using the well known expression given in The solid line in nfused silica(λ) = 1.561 − 3.969·10−4λ + 5.183·10−7λ2 − 2.384·10−10λ3 [nwater(λ) = 1.3231 + 3300·λ−2 − 3.2·107λ−4 [t is reasonable. The calculated value of t shown in t are slightly smaller indicating some additional loss, most likely due to scattering from the interfaces. The dotted line in The indexes of refraction are functions of the wavelength given by ·10−10λ3  and nwat2·107λ−4 . As seenThe relative cathode radiant sensitivity curve, as given in the Hamamatsu data sheet for the R928 photomultiplier tube (PMT), was read at selected values of the wavelength and these values were used to interpolate the cathode radiant sensitivity at arbitrary values of the wavelength. The resulting relative cathode radiant sensitivity is given in spect(λf) is a continuous emission spectrum obtained by interpolation of the measured uncorrected emission spectrum. The emission spectrum was measured using a photon counting detector so that the value of spect(λf) at any wavelength is proportional to the number of emitted photons at that wavelength. The spectral function s(λf) was estimated from the relation s(λf) = spect(λf)/∫spect(λf)dλf. E(λ) represents the interpolated values of the relative cathode radiant sensitivity data given in E(λ)·Minc(λ)/(λ ·〈ΕΜ〉), is shown by the solid line in Mcur/Minc, was a constant equal to 0.94 as discussed below). Combining all of the measurements, the final values of the quantum yield obtained using The symbol Mcuv/Minc, has to be relatively constant over the spectral region of interest (e.g. 480 nm to 600 nm). To obtain an estimate of the magnification ratio, a source of known flux has to be placed inside the cuvette. A possible source is a slab of Spectralon placed diagonally in a cuvette filled with water. The measured absorbance for this cuvette inside the IS can be calculated using The correspondence of the measured and expected values of quantum yield in δM stands for the ratio of magnification for fluxes originating in the cuvette to the magnification for the flux hitting the IS surface, Mcur(λ)/Minc(λ). The transmission and scattering contributions can be determined by measuring the absorbance of a cuvette filled with water outside and inside the IS [see The symbol e IS see . This prMcur = δM·Minc. Therefore the measurement of δM may not take into account all of the wavelength dependence. It is also necessary to estimate the wavelength dependence of Minc. The magnification is known to be a sensitive function of the reflectance of the material lining the surface of the IS. Minc = ρ(1 − f)/(1 − ρ(1 − f)) which is valid for the behavior of an ideal IS. Clearly the magnification is a sensitive function of the reflectance. The change in reflectance from 500 nm to 300 nm is only 3 % but the resulting magnification varies by as much as 57 %. Most likely the additional wavelength dependence of Minc could introduce a modification of the QY results of fluorescein shown in The magnification of the flux originating in the cuvette is related to magnification of the incident beam by The measurement of the QY of fluorescein, rhodamine B, and erythrosin B give values of 0.90, 0.34, and 0.018 that are close to the accepted values of 0.925, 0.31, and 0.02 respectively. This suggests that the proposed technique works for wavelengths above 450 nm. However the analysis of the data at lower wavelengths is complicated by the strong dependence of magnification on wavelength.2SO4. The solid curve shows the absorbance measured outside the IS, and the dotted curve shows the absorbance (multiplied by 3) measured inside the IS. In both cases the contribution from the buffer has been subtracted. There is a substantial difference in the shape of the spectrum between the two measurements. This difference can be rationalized by the presence of fluorescence emission in the case of measurements inside the IS. Due to the strong wavelength dependence of the magnification, the fluorescence emission has significantly higher detection efficiency factor. The values of the transmission coefficient and the scattering contribution are very similar to those shown in Aout can be understood by examining Aout affects both the numerator and the denominator in the same manner. Neglecting scattering (rs = 0) in t = 1) in The uncertainties of QY given in In addition to the four absorbance measurements, This paper describes a method for determining the QY of fluorophores using a commercial spectrometer equipped with an integrating sphere (IS) detector. The measured values of the QY of fluorescein, rhodamine B, and erythrosin B are in agreement with established values. The value of QY obtained for quinine sulfate (maximum absorption at 350 nm) is very sensitive to the form of the wavelength dependence of the IS magnification. The wavelength dependence of the radiant cathode sensitivity of the PMT and magnification factors of the IS detector were estimated from generic data provided by the manufacturers. For a more accurate determination, the wavelength dependence has to be characterized for the specific instrument that is used for the measurements. This is especially true for wavelengths below 450 nm. In principle, the wavelength dependence of the magnification could be performed using molecules with large excitation bandwidth and QY = 1 . The res


This paper reviews and extends searches for the direct pair production of the scalar supersymmetric partners of the top and bottom quarks in proton–proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20  In a theory with broken supersymmetry (SUSY) –9, the mThe scalar partners of the right-handed and left-handed chiral components of the top-quark state  –47. In tnt}+NLL) , hence tmentclass2pt{minimSearches for direct production of stops and sbottoms by the ATLAS collaboration have covered several possible final-state topologies. The experimental signatures used to identify these processes depend on the masses of the stop or sbottom, on the masses of the other supersymmetric particles they can decay into, and on other parameters of the model, such as the stop and sbottom left–right mixing and the mixing between the gaugino and higgsino states in the chargino–neutralino sector.Assuming that the lightest supersymmetric particle is a stable neutralino  mixture of different topologies that would arise from a SUSY model involving many possible allowed production and decay channels. The sensitivity to simplified models is discussed in Sect. More complete phenomenological minimal supersymmetric extensions of the Standard Model (pMSSM in the following ) are alsThe rich phenomenology of third-generation supersymmetric particles requires several event selections to target the wide range of possible topologies. A common analysis strategy and common statistical techniques, which are extensively described in Ref. , are empSignal regions (SR) are defined, which target one specific model and SUSY particle mass range. The event selection is optimised by relying on the Monte Carlo simulation of both the Standard Model (SM) background production processes and the signal itself. The optimisation process aims to maximise the expected significance for discovery or exclusion for each of the models considered.For each SR, multiple control regions (CR) are defined: they are used to constrain the normalisation of the most relevant SM production processes and to validate the MC predictions of the shapes of distributions of the kinematic variables used in the analysis. The event selection of the CRs is mutually exclusive with that of the SRs. It is, however, chosen to be as close as possible to that of the signal region while keeping the signal contamination small, and such that the event yield is dominated by one specific background process.A likelihood function is built as the product of Poisson probability functions, describing the observed and expected number of events in the control and signal regions. The observed numbers of events in the various CRs and SRs are used in a combined profile likelihood fit  to deterThe full procedure is validated by comparing the background predictions and the shapes of the distributions of the key analysis variables from the fit results to those observed in dedicated validation regions (VRs), which are defined to be orthogonal to, and kinematically similar, to the signal regions, with low potential contamination from signal.After successful validation, the observed yields in the signal regions are compared to the prediction. The profile likelihood ratio statistic is used first to verify the SM background-only hypothesis, and, if no significant excess is observed, to exclude the signal-plus-background hypothesis in specific signal models. A signal model is said to be excluded at 95 % confidence level (CL) if the CLcument}s , 61 of tSeveral publications, targeting specific stop and sbottom final-state topologies, were published by the ATLAS collaboration at the end of the proton–proton collision run at mentclass2pt{minimmentclass2pt{minimThe use of simplified models for analysis optimisation and result interpretation has become more and more common in the last years. The attractive feature of this approach is that it focuses on a specific final-state topology, rather than on a complex (and often heavily model-dependent) mixture of several different topologies: only a few SUSY particles are assumed to be produced in the proton–proton collision – often just one type – and only a few decay channels are assumed to be allowed. In the remainder of this section, several exclusion limits derived in different supersymmetric simplified models are presented. Details about how the MC signal samples used for the limit derivations were produced are available in Appendix A first series of simplified models is considered. It includes direct stop pair production as the only SUSY production process, and assumes that no supersymmetric particle other than the entclass1pt{minimaentclass1pt{minimaFigure mentclass2pt{minimentclass1pt{minimaentclass1pt{minimaThe limits reported in Fig. The cross-section limit is derived by combining the analyses discussed above. The SR giving the lowest expected exclusion CLFigure entclass1pt{minima in Ref. , which mentclass1pt{minimaTo maximise the sensitivity to the A similar combination is performed to target a scenario where the stop can decay as d at LEP –70. The Figure In the pMSSM, unless the higgsino–gaugino mass parameters are related by entclass1pt{minimaIf additional particles beside the stop and the lightest neutralino take part in the stop decay, the stop phenomenology quickly becomes complex. Even if the chargino is the only other relevant SUSY particle, the stop phenomenology depends on the chargino mass, on the stop left–right mixing, and on the composition of the neutralino and chargino in terms of bino, wino and higgsino states.Figure all Fig. a, which rio Fig. b assumesrio Fig. c is charrio Fig. d assumesSummarising, in the simplified models with wed Fig. b. A smalGeV Fig. c, where Although the pair production of The exclusion limits were first derived in a scenario in which the pair-produced 0 % Fig. a, or thrFigure The assumption on the branching ratio of the ~10 Fig. c are theUnder the assumption that no supersymmetric particle takes part in the sbottom decay apart from the lightest neutralino, the sbottom decays as entclass1pt{minimaFigure If other supersymmetric particles enter into the decay chain, then multiple decay channels would be allowed. Similarly to the stop, the case in which other neutralinos or charginos have a mass below the sbottom is well motivated. The branching ratios of the sbottom to the different decay channels depend on the supersymmetric particle mass hierarchy, on the mixing of the left–right components of the sbottom, and on the composition of the charginos and neutralinos in terms of bino, wino, and higgsino states.An exclusion limit is derived under the assumption that the sbottom decays with a branching ratio of 100 % into entclass1pt{minimamentclasspt{minimaThe last case considered is one where the pair-produced sbottoms decay through entclass1pt{minimaThe limit, derived as a function of mentclasspt{minimaThe interpretation of the results in simplified models is useful to assess the sensitivity of each signal region to a specific topology. However, this approach fails to test signal regions on the complexity of the stop and sbottom phenomenology that appears in a realistic SUSY model. To this extent, the signal regions are used to derive exclusion limits in the context of specific pMSSM models.No new source of CP violation beyond the Standard Model. New sources of CP violation are constrained by experimental limits on the electron and neutron electric dipole moments.No flavour-changing neutral currents. This is implemented by requiring that the matrices for the sfermion masses and trilinear couplings are diagonal.First- and second-generation universality. The soft-SUSY-breaking mass parameters and the trilinear couplings for the first and second generation are assumed to be the same based on experimental data from, e.g., the neutral kaon system .With the above assumptions, and with the choice of a neutralino as the LSP, the pMSSM adds 19 free parameters on top of those of the SM. The complete set of pMSSM parameters is shown in Table The pMSSM  is obtaiThe common masses of the first- and second-generation squarks have been set to a multi-TeV scale, making these quarks irrelevant for the processes studied at the energies investigated in this paper. This choice is motivated by the absence of any signal from squark or gluino production in dedicated SUSY searches performed by the ATLAS , 73–76 aAll slepton mass parameters have been set to the same scale as the first- and second-generation squarks. This choice has no specific experimental or theoretical motivation, and should be regarded as an assumption.A decoupling limit with n states , 84.For t-μ/tanβ . The stoThe trilinear couplings The gluino mass parameter These assumptions reduce the number of additional free parameters of the model to the mass parameters of the electroweak sector  to lesstralinos . The con-enriched pMSSM These models are defined such that Higgs and Exclusion limits for these pMSSM models are determined by combining many of the SRs defined for the searches discussed in this paper (t0L, t1L, tb,Figure The signal regions that dominate the sensitivity are the tb, t0L-SRC1 and t1L-bCd_bulk at low values of Figure Finally, Fig. More informations about the limits obtained, including the SLHA files for the points mentioned in Table The search programme of the ATLAS collaboration for the direct pair production of stops and sbottoms is summarised and extended by new analyses targeting scenarios not optimally covered by previously published searches. The paper is based on 20 We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently.


The rate of modern contraceptive use will be on an increase and maternal mortality on a decrease if women had a good knowledge on family planning and its methods. This survey was designed to evaluate the knowledge and determine the future desires to use contraception among women in Urban Cameroon.We conducted a cross sectional community based survey from March 2015 to April 2015 targeting women of childbearing age in the Biyem-Assi Health District. Participants were included using a multistep cluster sampling and the data collected face to face by well-trained surveyors using a pretested and validated questionnaire. The data were then analysed using the statistical software Epi-Info version 3.5.4. Proportions and their 95 % confidence intervals were calculated and in a multiple logistic regression model with threshold of significance set at p value ≤0.05, the odds ratio was used as the measure of association between selected covariates and future desire to use contraception.Among the 712 women included in the survey, the mean age was 27.5 ± 6.5 years. A good proportion (95.6 %) identified contraception as used to prevent unwanted pregnancy and this showed an increasing trend with increasing level of education. Also, 77.5 % thought that contraception should be used by all sexually active women. The most cited contraceptive methods were; condom 689 (96.8 %), oral pills 507 (71.2 %), and implants 390 (54.8 %). Their main sources of information were the health personnel (47.7 %) and the school (23.6 %). It was estimated that 31.0 [25.5–37.0] % of current contraceptive non-users had no desire of adopting a contraceptive method in the future. With the level of education, age, and marital status controlled, the number of unplanned pregnancies more than 3 , and past adoption of more than 2 modern contraceptive methods  were statistically significantly associated to decreased desire to adopt contraception in the future. The level of knowledge showed an association though not statistically significant with future desire to use contraception .The knowledge of women of childbearing in the Biyem-Assi Health District was relatively high but still unsatisfactory. The proportion of contraceptive non users who have no desire of adopting any contraceptive method in future is still unacceptably high. Policy makers should improve on their strategies while empowering the health personnel and working in collaboration with the education ministries. The rate of use of family planning services in the developing world and more particularly in Cameroon remains unsatisfactory , 2. The The adoption of any contraceptive method requires prior knowledge of the method. A good knowledge of the use of family planning methods and their benefits/side effects depends on the effectiveness of the counselling and sensitization of the risk population , 4, 6, 8A recent survey 2015) in Yaoundé–Cameroon showed that 20.4 % of women in a union had an unmet need for family planning and that the potential demand for family planning was just at 70.6 % . Accordi5 in YaouGiven that a good knowledge influences perceptions and will improve on the future desires to use contraception. Policy makers need to stress on the need for sensitizers and family planning providers to remain very explicit in their interventions. A good knowledge and perception is indispensable for the fight against the unsatisfactory potential demand of family planning services and therefore its consequences. This survey was designed to evaluate the knowledge and the future desire to adopt family planning methods in a sample of women in urban Cameroon among which unmet need for family planning had been reported high .We conducted a cross sectional community based survey in the Biyem-Assi Health District   targetinIn this process, all four health areas were included in the survey and the whole district divided into a total of 70 geographical clusters from which 50 were randomly selected with replacement. In a selected cluster, a road junction was randomly selected from all major junctions and a street selected by tossing a plastic bottle. In a selected street, all households on the left hand side of the interviewer were included in a successive manner. Prior to data collection, a two-day training session was organised by the principal investigator to enlighten the surveyors (of both gender) on the consenting and data collection procedure. All eligible and consenting participants within a selected house hold were included in the survey. Data were collected using a pretested and validated questionnaire administered face to face by well-trained surveyors. Data collected included evaluation of the knowledge of participants on family planning and their intentions to use contraception in the future. The data were collected from March 2015 to April 2015.The data from filled and validated questionnaire were then entered into a predesigned data capturing sheet and analysed using the statistical software Epi-Info version 3.5.4. Major analysis included calculation of proportions  and their 95 % confidence intervals where relevant for qualitative variables and means with standard deviations for quantitative variables. With potential confounders like age, level of education, marital status, and religion checked in a multiple logistic regression model, the odds ratio was used as the measure of association between selected covariates  and the outcome of interest (future contraceptive use). All with a statistical significant threshold set at p value ≤0.05). The knowledge variable was divided to level of knowledge below or above average depending on the number of right answers given to the set of questions to evaluate the knowledge, that is above or below 50 % of correct answers. The number of modern methods adopted in the past was divided into the number of modern methods adopted in the past above two or less than or equal to two while the number of unplanned pregnancies was divided into above three and less than or equal to 3 years. The results were presented on tables, figures and some written out.Among the 712 women included in the survey, the mean age of the participants was 27.5 ± 6.5 years and the most represented age group range was 20–29 years. Most (60 %) were in a union, 96.7 % Christians and about 8 in every 10 had acquired at least a secondary education. All the women interviewed had heard of contraception in their lifetime. Figure Of the 712 participants, 552 (77.5 %) thought that contraception should be used by all sexually active women while 35 (4.9 %) thought only women with at least one child should use contraception. Unplanned pregnancy is a problem among all sexually active women, therefore contraception should be adopted by any woman who is sexually active and not planning to get pregnant any time soon. A relatively high proportion thinks only women with at least a child should adopt contraception. This could be explained by the beliefs and misinformation on some reversible family planning methods associated to risk of infertility.Figure Table Table Out of 708 participants who responded to contraceptive use, 61.758.0–65.3] % were currently using at least one contraceptive method and 91.8[89.5–93.7] % had adopted at least one contraceptive method in their lifetime. This rate of contraceptive practice is relatively high but does not give a clear picture of the contraceptive need of the population. A survey carried out in this population in the same year revealed that 16.4–24.8 % of women in a union had an unmet need for family planning [ % were cThis shows to an extent the magnitude of work awaiting family planning providers in convincing and dissuading this population to adopt effective contraceptive methods. However a survey carried out in this population during the same time frame revealed that discussion of family planning within the couple and husband’s approval of contraception were two major determining factors keeping unmet need for family planning high . Also, tWith level of education, age, marital status and religion controlled, the level of knowledge showed an association though not statistically significant with future desire to use contraception . The lower the knowledge on contraception and its methods, the less likely had they plans to adopt contraception in future. This is but logical given the fact that contraceptive use requires a good knowledge of its functions and methods. Many surveys have associated good knowledge to increased contraceptive use [7, p = 0.With the level of education, age, marital status and religion controlled the number of unplanned pregnancies more than 3 , and past adoption of more than 2 modern contraceptive methods  were statistically significantly associated to decreased desire to adopt contraception in the future. Women who have adopted more than two methods of contraception most often have suffered from side effects and inconveniences of different methods that made them move from one to another. When these complaints are not clearly addressed by the health provider, the women turn to withdraw from contraceptive use. Contraceptive non-use has been described to be highest among women with unintended pregnancies . This reThis survey evaluated just the knowledge of women of childbearing age on family planning. The perceptions and attitudes of this population towards family planning were not evaluated. Given the vital role men play in the decision making, a survey is required among men. Also, the health personnel who are at the centre of the dispensation of knowledge and provision of family planning services were not evaluated in this survey. However, the level of knowledge and future desire to use contraception pictured from this survey shows the necessity of the health personnel and family planning sensitizers to improve on their strategies in order to improve on the knowledge of the population in need. This survey was well designed with adequate methodology and all put in place to check for bias. It types out the situation on the level of knowledge on family planning in an urban setting in Cameroon.The knowledge of women of childbearing in the Biyem-Assi Health District was relatively high but still unsatisfactory. A high proportion (31.0 %) of contraceptive non users had no desire of adopting any contraceptive method in future. Major sources of information on contraception are the health personnel and the school. With the level of education, age, and marital status controlled, the number of unplanned pregnancies more than 3, and past adoption of more than 2 modern contraceptive methods are statistically significantly associated to decreased desire to adopt contraception in the future. The level of knowledge showed an association though not statistically significant with future desire to use contraception. Policy makers should improve on their strategies while empowering the health personnel and working in collaboration with the education ministries to encourage teachings on family planning and its methods to at least all secondary school leavers. More surveys should be carried out in this field to evaluate the health care providers as well as study the perceptions and attitudes of this population.