The modulation of surface plasmon resonance (SPR) and the implications in the MoO3 transmittance spectrum is described by applying an effective medium theory. The transmittance modulation was modified by variating three parameters, the radius of the NPs, the concentration of the NPs as well as the variation of the MoO3 thin films thickness. It was found that the nanoparticles concentration is the most important parameter in the transmittance modulation. Additionally, the orthorhombic and monoclinic structure of MoO3 was studied, from which it was obtained that the monoclinic structure of the MoO3 doped with Au – NPs favors the reduction in the transmittance values in the visible region which is associated with the increase of the SPR signal. Similar analyses are performed for non-resonant nanoparticles such as Ti, where it was found that optical modulation is not as marked as the case of gold nanoparticles.The growing interest in functional transition metal oxides for efficient energy consumption or in the bio-sensing process; indicates that is necessary to develop a new theoretical method that describes experiments. This article presents a new theoretical methodology to characterize molybdenum trioxide (MoO Developing new devices with interesting optical properties has been a technological and experimental challenge7. In order to describe optical properties from a theoretical point of view, it have been developed sophisticated multiphysics modeling finite element commercial software, such as Comsol Multiphysics, Lumerical FDTD or BEM which allow you to calculate, reflection or transmission frequency-dependent or scattering parameters and near or far electromagnetic field projections. However, many of them are difficult to access since they are expensive or they are not very intuitive software’s. So, implementing new theoretical formalisms to characterized and analyzed thin films with new, interesting and unexpected effects could be useful for developing new devices with different kinds of optical properties. There are some different approaches to characterize thin films10, particularly for thin films doped with different materials, using an effective medium theory to describe the radiation interaction with the doped thin films could be an alternative. In effective medium models, one of the most important approximation is the large size limit. The most studied formalisms that consider effective medium theories (EMTs) are Maxwell Garnett or Bruggeman, these models are applied to described materials with granular topology11 and materials with intermixed components12, respectively. These EMTs are based on small spheres approximation, which means that the size of the particles is small compared with the incident radiation wavelength13. An alternative formalism to study effective mediums is the refractive index proposed by van de Hulst15. This simple theoretical approach has been used at different configurations; to mentioned some, as colloidal systems17, or colloidal monolayers10, obtaining good agreement with experimental measurements. The main difference with Maxwell Garnett and Bruggeman is that van de Hulst depends on the forward scattering amplitude, which predominantly depends on the nanoparticle size. Hence, this approach can be more robust since not have the size particle limitation, that is the case of the two EMTs, as already mentioned. Being this, one important factor in device design for specific applications. Combining the effective medium approach with well stablished reflection or transmission coefficients18 to predict the behavior of undoped and doped thin films, could be a novelty method to study thin films.Optical properties of different kind of systems has attracted attention for many researchers around the world3), tungsten trioxide (WO3) and titanium dioxide (TiO2), to name a few of them, will be useful to predict the material optical behavior21. In recent years, MoO3 has been extensively studied for their potential applications as a biosensing, temperature or gases sensors, also, as a layer in solar cell devices, photocatalytic material or as an electrochromic layer in smart windows for efficient energy consumption applications in buildings24,. Different deposition techniques have been studied such as sputtering rf or dc, sol-gel and evaporation, in order to improve their properties for different applications24. In addition to deposit techniques, different configurations of TMOs such as MoO3 doped with ZnSe nanoparticles, Wx–y1–TixNiyO3, W–x–y1TixMoyO3, or as two-layer systems MoO3 / CdSe, Pt / MoO3 and Au / MoO3 have been studied28. However, an interesting phenomenon arises when doping some of the TMOs with some kind of nanoparticles, e.g., doped MoO3 with Au nanoparticles29. The metallic nanoparticles (NPs) incorporation in the molybdenum oxide matrix extremely modifies the optical properties; mainly associated with surface plasmon resonance (SPR)30. The phenomenon arises from the interaction of the electromagnetic field of an incident light beam on the surface of the material that derives in collective oscillations of free-charge carriers31. This phenomenon radically improves the optical modulation by providing unprecedented control over light-induced excitation which is a priority in the chromogenic properties where it wants to be used the photogenerated electrons originated by visible light irradiations. Even more, these same photogenerated electrons can be used in photocatalytic experiments where it is desirable to absorbed visible light for the degradation of inorganic compounds in aqueous systems32.Employing this model to describe the behavior of various materials specifically the transition metal oxides (TMOs) such as molybdenum trioxide  of MoO3 thin films doped with Au – NPs. It should be noted that these nanoparticles are considers as a noble metal, known as plasmonic particles36. In order to corroborate the plasmonic effects, it will be analyzed the case of MoO3 thin films doped with Ti – NPs, which corresponds to a non-resonant particle37. As a complement, the concentration, and NPs radius will be studied. These studies will be carried out by the implementation of the effective medium theory that opens a novelty alternative for the optical characterization of different thin films particularly in this work it will be focused in MoO3 thin films. Specifically, to our knowledge, in the literature, the van de Hulst model has not been applied to describe the optical modulation caused by nanoparticles embedded in a thin film. Previously van de Hulst model was used to described colloidal systems. Thus, in this work, we propose a simple EMT that could be used to describe the optical modulation of doped MoO3 thin films with Au – and/or Ti – NPs which are of interest in areas of energy efficiency in buildings, in clean energy generation applications or even more bio-sensing process25.Thus, the effect of the 3 thin films is carried out through the effective media theory that considers certain particles immersed in a matrix medium that could be considered as a dilute turbid system where the volume occupied by the particles is small compared to the total volume, the effective refractive index is modeled with the van de Hulst approximation. Additionally, is well known that the particle’s contribution depends on the refractive index, shape and particles’ size38. Considering this, the effective refractive index is given by16,The theoretical modeling of the undoped and doped MoOan and bn, are known as scattering coefficients, they are complex functions of Ricatti-Bessel and its derivatives, more details are reported in ref. 39. It is known that the contribution of this parameter will be more evident for cases of particles with radius bigger than 10 nm39. To infer the optical properties of doped thin film, it is necessary to consider the reflection or the transmission coefficients of the system as can see in Fig. mentclass2pt{minimmentclass2pt{minim17 which is given bys or p which depends on the case that is working on. Finally, the h parameter is the thin film thickness. For the s polarization the terms of Eq.  spectrum. On the other hand, the transmittance spectrum of e.g., around the visible range, the use of MoO3 alone will not be enough to modulate the visible electromagnetic radiation. This is the reason why doped MoO3 thin film can be interesting to discuss. Hence, it will be investigated the evolution of the MoO3 thin films transmittance spectra with different (Au and Ti) nanoparticles concentrations. Additionally, to confirm that our results are compatible with the description of the MoO3 thin films, the value of the band gap was computed by the Tauc’s model that considers an indirect bandgap transition. The obtained values are between 3.13 and 3.15 eV for the α – phase and between 2.97 and 3.00 eV for the β – phase, these values are similar to those reported previously26.The transmittance spectra of 3 thin films can be observed, mainly in the visible region. The generated band (between 500 and 700 nm) with a minimum value around 600 nm is associated to the surface plasmon resonance due to the incorporation of Au – NP in the MoO3 matrix, that might corroborate the validation of the proposed theoretical model by the experimental observation presented in reference 3 matrix, for possible applications where the transmittance modulation in the visible range, could be the most important parameter25. The proposed model considers three important parameters in the thin films doping: the radius of the NPs, the volume filling fraction  and the thickness of the thin films. Firstly, it will be discussed the effect of the NPs radius (5 and 15 nm) in the transmittance spectrum of the MoO3 for 3 thin films transmittance, is the NPs concentration change.In Fig. 43, as can see in the inset of the Fig. α – phase. So, in the following results it was fixed at 5 nm the radius of the Au – NPs. Thus, studying different cases (thickness and concentrations) could give more physical insight to understand better the optical properties of these doped thin films. In Fig. As already shown, the NPs radius not contributes significantly in the optical modulation in this particular case. As it is known while the radius of the nanoparticle increases a red-shifting on the extinction efficiency spectra is presentedα – phase, also seen in the extinction efficiency coefficient plotted as an inset in Fig. 3 shows an amorphous structure that might be related to a higher free electron density. More details of this behavior will be discussed in section Mechanism to enhanced optical properties. Other difference is the band centered at 350 nm vanish in 3, the radius of the nanoparticles, is not a strong parameter for tuning the intensity of the SPR signal.As a comparative now considering the case of α – phase, it was analyzed the SPR signal as a function of the thickness and the Au nanoparticles concentration, as can be seen in Fig. For completeness, the thickness variation of the thin films will be studied, see Fig. 3 have an important role in the behavior of modulation resonance. Additionally, at this wavelength the transmittance decreases 0.1 on transmittance value for the concentration of 3.5%, as depicted in Fig. Something that we should mentioned is that another configuration was analyzed, but with few examples, due to the similar behavior with Au – NPs. This configuration is 3 thin films, for different applications as the titanium28. The used parameters in the previous sections will be the same in this case, only with a variation of thicknesses, which are bigger in these cases, with the aim to compare and take a look at which configuration could be more useful for the optical modulation. Figure 3 matrix because the transmittance spectrum shows slight differences as compared with Fig. Finally, it will be tested the theoretical model with another material commonly used as a dopant in the MoO3 thin film thickness, fixing the Ti – NP radius at 5 nm and the concentration at 1%. Figure et al7. reported TMOs are good candidates to be plasmonic materials which combined with non-resonant particles can be generated a band centered at 450 nm which suffers a red-shift to a value ~ 820 nm and as Liu mentions, this band is associated to the SPR phenomenon. So, the incorporation of Ti – NPs, in the MoO3 can increase the SPR signal of MoO3 and the red-shift corroborate the presence of the resonant electrons as the thickness increases. Figure In the same way as the section of thin films doped with Ti nanoparticles, let’s investigate which is the effect of varied the MoO3 shows the best transmittance modulation in the visible range. Now it will be considered the change of the MoO3 structure. Figure 3 transmittance spectra for the NPs radius of 5 and 15 nm, respectively. In this case, the NPs concentration and the thickness were fixed with the same values as in the section of thin films doped with Au nanoparticles. Beside, the transmittance spectrum still shows particular features such as the fundamental transmission edge around 420 nm, a characteristic associated with MoO3 thin films.Therefore, comparing these results with the Au – NPs doped 3 thin film thickness, the results are shown in Fig. 3 from the peak centered at 450 nm to 1000 nm as the thickness is increasing from 100 to 200 nm, respectively, as shown in Fig. β – phase, the red-shifting of the SPR band is more intense and corroborates that was found for the case of Au – NPs. Thus, for the non-resonant particles, the behavior is the same, showing a remarkable red-shift of the SPR band as can observe in Fig. 3 also enhances the transmittance modulation, unlike the orthorhombic structure where the transmittance changes are not promising.Finally, if the concentration is fixed at 1% and considering 5 nm of radius for Ti nanoparticles and leaving free the MoO3 thin film has less impact in the transmittance spectra in the visible range, than the Au – NPs or even in Ag – NPs. These results show the importance of plasmonic nanoparticles embedded in MoO3 thin films, opening a new methodology to characterized and developing new functional materials.By looking Figs. 3 thin films have a very wide technological application, understanding the modulation mechanism of the transmittance spectrum when it is doped with plasmonic nanoparticles and non-resonant particles, it becomes a fundamental aspect in the research. Therefore, this section describes the possible mechanism of the differences in the optical modulation that was presented by the α – phase and β – phase. On the one hand, it was shown that the β – phase favors the modulation of the SPR signal, by intensifying the resonance phenomenon. Studies by Liu et al.7 mention that the modification of the MoO3 surface, it will strongly be associated with more available free electrons near the surface, and they conclude that if the density of free electrons is increased; the SPR signal also increases. This behavior can be corroborated with the arising of a band and the red-shift which experiment this band. Likewise, Zhang et al.18 reported that the SPR effect is intensified when the free electrons concentrations increase on the surface. Zhang mention that the behavior is associated with the presence of oxygen vacancies and with a low crystalline structure. In addition, Linic et al.6 mention that one of the mechanisms of charge carriers transfer occurs on the semiconductor surface, under the assumption that the plasmonic nanoparticles and the semiconductor are in direct contact, allowing a rapid transfer of charge carriers. Therefore, the metal plasmonic nanoparticles essentially act by absorbing resonant photons and transfer the generate photo-electron, formed in the resonant excitation process, to the semiconductor.Due to the MoOet al. mentions as an assertion in our model. Moreover, considering that Liu and Zhang highlight the importance of the oxygen vacancies and the low crystallinity in the MoO3 structure and how these features are related to the SPR signal increase. So, it might be correlated that these characteristics are essential for increasing the SPR signal and enhanced the optical properties. According to the obtained results, the intensification of the SPR signal could be attributed to the presence of these three properties. In previous works has been demonstrated that the β – phase has a sub-stoichiometric amorphous structure associated with oxygen vacancies in the MoO3 matrix44 unlike the α – phase where its crystalline domain is bigger and available oxygen vacancies are less than β – phase44. The importance of oxygen vacancies to explain the increase in the SPR signal is of the utmost importance since these vacancies would function as electron traps, which could be absorbed the generated resonant electrons. Therefore, a larger number of photogenerated charge carriers, due to the resonance in a structure with higher oxygen vacancies density, the probability that these vacancies absorb these resonant electrons will be very high. Another aspect that supports the hypothesis that a higher free electrons density in this structure, higher intensity in the SPR signal, is the red-shift of the SPR dip, which is shown in the transmittance spectra of the β – phase, when it is compared with the α – phase7. In another way, the main contribution of the titanium nanoparticles, is weak on the MoO3 thin film compared with the gold nanoparticles. As expected no-resonance behavior is present in this case, so the changes in the transmittance signal are not significant. The simulation with a non-resonant particle is useful as a comparison between resonant and non-resonant particles and showing the potential of using noble metals as dopants in thin films for developing new devices. One thing that should be mentioned is that the concentration of the Ti nanoparticles just decrease a little the transmittance and have a shift on the maximum peak of transmittance. Meanwhile, if the thickness of the MoO3 increase, a bigger shift can be seen on the transmittance, which could be interpret as a shift due to the presence of a plasmonic resonance as Liu, et. al. reported7. The effect of the film thickness is not observed as well as in the case of embedded gold nanoparticles, due to the presence of the plasmonic nanoparticles which resonance signal is just after de peak of the transmittance, making this phenomenon not well remarkable as in the case of titanium particles, which are non-plasmonic particles.Taking these studies into account, firstly it is considered what Linic 3 thin films without doping and doping with resonant (Au) and non-resonant (Ti) nanoparticles, through the implementation of effective media theory. As can be seen, the applicability of the theoretical method, for the prediction of transmittance spectra can be corroborated by qualitative comparison with some experimental results. Among the analyzed parameters, the most important in the transmittance modulation is the nanoparticles concentration and the MoO3 phase. It was found that the higher the nanoparticles concentration (3.5%), the intensity of the SPR signal is higher. It is possible to modulate up to 0.55 on transmittance for the alpha phase and for the beta phase the modulation reaches a value of 0.85 on transmittance, so the beta phase of the MoO3, is the phase where the optical modulation is benefited. This result is associated with more oxygen vacancies density in the beta phase in which the generated photoelectrons in the resonance phenomenon, could be injected or trapped by the anionic vacancies present in the semiconductor. These results are important for the optical tuning devices design. Additionally, as a comparison, the changes in the transmittance spectrum are studied when the MoO3 is doped with Ti – NPs. Similar behavior is observed, where at a higher Ti nanoparticles concentration and for the β – phase, the band associated with MoO3 absorption suffers a red-shift. However, this cannot be compared with the changes presented in the Au – NPs case but it is interesting to observe that with the incorporation of Ti in MoO3 matrix it can be modulated the maximum absorption band. From the performed simulations, an interesting result has been found in MoO3 thin films. As in chromogenic materials, the SPR signal is also be favored when the MoO3 is in the β – phase. These results have many implications in technological applications, e.g., in the bio-sensing process, in energy efficiency or even more in harvesting electrons for clean energy generation.In this work, a new theoretical model was developed to characterize MoO


Paired t test indicated that the mean of the heights measured by the laser meter is statistically equal to that of the graduated ruler. Measurements with laser meter did not show bias and had mean error of 0.0745. The standard deviation of the differences indicated dispersion of errors of 0.97, equal to that shown in the graduated rule. Laser meter presents an alternative method for estimating the commercial height of trees in tropical forest in the Brazilian Amazon. There was no tendency to underestimate or overestimate the commercial heights of trees. Use of the laser meter is potentially of use for measuring the commercial height of trees in tropical forests.Commercial height of the tree is a key variable for estimating the wood stock in tropical forests managed for timber production purposes. Most available measurement devices suffer limitations in this type of forest, promoting low precision measurements with high variation errors. The laser meter device appears as a viable alternative, as in addition to using trigonometric principles, it is not necessary that the device is close to the eyes of the meter to carry out the measurement. The device can be used to measure commercial height of trees on flat or sloping terrain, at different distances from the tree. However, there are no studies evaluating the precision of this device. The objective of this study was to determine the precision of the laser meter method for estimating the commercial height of trees, as compared to the actual measurement in a tropical forest in the Brazilian Amazon. Measurements were made on 300 trees with commercial height between 7 and 14 m. Actual commercial heights were measured with graduated ruler. Applied tests were paired  A new method and device to measure commercial height of trees in natural forests is proposed. The method has, besides practicality, good precision, and low cost, a great differential: The technician does not need to use the device close to the eyes. The technician observes the laser beam in the tree trunk and remains in the same position to realize the three measures necessary to obtain the commercial height. The device can be used to measure commercial height of trees on flat or sloping terrain from any distance from the tree. Among the requirements for SFMP approval, it is required the quantification of the wood stock of the feasible trees for harvest CONAMA, . The wooMeasuring the commercial height of trees is a difficult in tropical forests when compared to planted forests  of height measuring devices in tropical forests encourages the use of conventional direct measurement  methods, such as the use of graduated or telescopic rulers, which results in expensive and costly , and has a measuring range of 50 m with a precision of +2 mm, besides being resistant to falling and splashing water and shows the readings directly in the digital format.The laser meter device calculates tree height by simply measure distance of three points on the tree trunk. The first point is the commercial height to be measured, second point is in the rectangular direction for forming a right triangle, and the third point is at the base of the tree. Formation of two rectangular triangles allows the commercial height to be obtained at any distance from the tree and on sloping terrain.2.3® and Microsoft Office Excel® 2013.Commercial heights were measured, between 7 and 14 m, being the maximum range offered by the graduated rule, in 300 trees randomly selected. Measurements made with the graduated ruler and with the laser meter were obtained by the same technician, to carry out the control and to avoid the influence of the technician on the collected data. Statistical analyses were performed using the software RStudiot test (α = 0.05) was applied in order to compare the commercial heights obtained by the laser meter in relation to those obtained by the graduated ruler. The hypotheses of the test were as follows:l = commercial heights averages measured with laser meter and μr = commercial heights averages measured with graduated ruler.Height frequency histogram was established with the number of classes determined by the Sturges method . Paired Y^ = heights measured with laser meter and Y = heights measured with graduated ruler.Furthermore, the residuals from the commercial heights obtained with laser meter were calculated as follows:Sd). The bias shows the existence of some tendency among the residues, the MAD reflects the amplitude between the residues, and the Sd expresses homogeneity of the residuals. Bias:Additional statistical tests were applied to complement the graphical analysis of the residuals: bias, mean absolute deviation (MAD), and standard deviation of differences (Mean absolute deviation:Standard deviation of differences:Coefficient of determination:Sturges’ formula (1926):where Yi = heights measured with graduated ruler, Y^i = heights measured with laser meter, n = number of observations, di=(Yi−Y^i), Y¯ = heights averages measured with graduated ruler, and Nc = number of classes.3t test paired, in order to compare the heights measured by the graduated ruler and laser meter  of 1.960  of 0.0745, indicating homogeneity. The standard deviation of the differences indicated dispersion of errors of 0.97, equal to that shown in the graduated rule Table .The errors plotted in graphs to facilitate the visualization of its distribution show that they varied between ±2.5% and that there are no tendencies. Homogeneity and nonbias observable between the methods are shown with the estimated line drawn from the commercial heights measured with the laser meter simultaneously to the cloud of points represented by the heights measured by the graduated ruler  and the proportion of reflection based on which distance is calculated and detector settings in general, including technical specifications that may be proprietary and which may change over time as new models replace older ones. It is possible that laser‐specific correction functions are developed for forest types, but this would require a lot of additional research in this field.5The laser meter has been shown to be at least as good as “standard” methods for estimating the commercial height of trees in tropical forest in the Brazilian Amazon. There was no tendency to underestimate or overestimate the commercial heights of trees.The use of the laser meter is only suggested here for measuring the commercial height of trees in tropical forests, not the total height, or for forests with grester. It is not recommended for measuring total height of trees and no measurements on forests planted with greater spacing between trees. In measuring total height, the leaf area of the tree can affect the laser reflectance, causing an error in the measurement of the device. In forests planted with trees at spacings larger, there is a high incidence of light in the tree trunk, affecting the visualization of the laser.Future studies should evaluate this type of apparatus in other forest conditions that differ in structure and with other instruments that differ in the specifications to develop a better basis for estimating the actual commercial heights of these measurements.It would be particularly interesting to evaluate the accuracy of the laser meter in trees of commercial heights greater than 14 m. This could be easily accomplished by comparing with true commercial heights measured on trees after harvest.None declared.AS and MAS conceived the ideas and designed the study. AS collected data. AS and PCGP conducted analysis of data and perfected the method. AS, MAS, and PCGP wrote the article. All authors contributed critically to the drafts and gave final approval for publication.


BackgroundIn obese children, lipophilic medications should be dosed to total body weight (TBW) and hydrophilic medications to ideal body weight (IBW). During emergencies, these weights need to be estimated to ensure that urgent drug therapy is accurate and safe. The Mercy method is a well-established weight estimation system that has recently been adapted to provide estimations of body length in children. It was therefore conceivable that this could be further modified to provide estimations of IBW.MethodsA model was developed a priori using the Mercy method’s humeral length (HL) segments to predict IBW. The accuracy of this model was then tested in a sample of 13,134 children from the National Health and Nutrition Examination Survey (NHANES) datasets. The accuracy of IBW estimation was determined from the percentage of estimations falling within 10% (p10) and 20% (p20) of true IBW. The model was also tested to see the accuracy of the detection of obesity in the study sample.ResultsFrom the sample of 13,134 children, a subset of 1,318 obese children were identified. In this subset, the new Mercy method model achieved an IBW estimation accuracy p10 of 66.9% and a p20 of 95.1%. For the detection of the obese child, the model had a sensitivity of 88.6% and a specificity of 75.8%.ConclusionsThis study established that the Mercy method can be modified to provide a reasonably accurate estimation of IBW in obese children, with very few critical errors. The ability of the model to identify the obese child was also reasonably accurate, on a par with other such predictive methods. While other accurate methods of estimating both TBW and IBW exist, such as the Paediatric Advanced Weight Prediction in the Emergency Room eXtra-Long tape (PAWPER XL tape), the modified Mercy method is an acceptable alternative if such other devices are not available. Background The World Health Organization has recommended that the doses of hydrophilic drugs be calculated according to ideal body weight (IBW) in obese children . This isDuring medical emergencies in children - when a child cannot be weighed to determine TBW and there is no time to calculate IBW - it is necessary to be able to estimate both these dose scalars before drugs can be administered . DevicesImportanceThe ability to estimate IBW is important since many drugs used in the resuscitation of critically ill or injured children are hydrophilic, and since poor outcomes in obese children have been ascribed to dosing errors based on TBW estimations ,9. An adObjectivesThe objectives of this study were to develop a model by which the Mercy method could be adapted to provide an estimation of IBW; to validate this model in a large database; and to develop tables that could be used by clinicians to estimate TBW as well as IBW by using the standard Mercy method measurements.Description of the Mercy methodThe Mercy method, which is validated in children up to the age of 16 years, makes use of two anthropometric measurements to generate an estimate of TBW . MeasureDevelopment of the model to predict IBWThe publication of a validated method to estimate children’s length from HL created the possibility of predicting IBW from HL . Our modFirstly, the recumbent lengths (or heights) predicted by the Mercy system for each centimetre increment of HL were collated into an electronic worksheet (Microsoft Excel for Mac Version 16.35 (2020), Microsoft, Redmond, WA) .Secondly, since IBW is very closely related to recumbent length, it was possible to create a table of IBWs for each range of HLs . This waThirdly, the IBW value in each category was cross-checked against an IBW calculated from length using the Traub-Kichen formula . This foFourthly, since IBW should only be used in obese children, a threshold value for TBW was calculated to inform the user which child would be classified as obese, in which case the value for IBW would be relevant. This threshold value was calculated in two ways. The PAWPER XL-MAC weight for a child with a habitus score of 5 (obese) was identified for each length-group from previously published data as an indicator of an obese weight . In addiFinally, spreadsheet formulas were created with the Mercy method HL categories, the predicted recumbent length, the predicted IBW, and the predicted TBW at which the child should be considered to be obese. These formulas were then used to calculate the output data for the validation component of the study.Validation of the IBW modelth-centile (IBW50) method was used as the reference method for IBW in this study and was calculated as the weight at the 50th centile of BMI-for-age for each child. This method is generally regarded as the most accurate and useful methods of determining IBW [The National Health and Nutrition Examination Survey (NHANES) datasets A, B, C, D and G (datasets from the 1999-2000 to 2011-2012 surveys) were obtained from the Centers for Disease Control (CDC) website . The demData analysis50 denoted overall accuracy. The performance of the TBW estimation of the Mercy method was also evaluated using the same methodology. Subgroup analyses of the performance of the Mercy method were performed in age-categories: ≤2 years, 2.1 to 5 years, 5.1 to 10 years, and >10 years.The success of the IBW estimation of the model was evaluated using statistical methods centred on percentage error analysis. Three primary statistical measures were used to assess performance: mean percentage error (MPE) indicated the estimation bias; the 95% limits of agreement of the MPE (PELOA) represented the estimation precision; and the percentage of weight estimations that fell within 10% (p10) and 20% (p20) of calculated IBWThe accuracy of the identification of obese children by the model was evaluated by determining the sensitivity and specificity of the model (performed in the entire pooled dataset). A BMI-for-age Z-score threshold of 2.0 was used as a definition of obesity.50. A p10 >70% and a p20 >95% was considered to be an acceptable accuracy of estimation [The primary outcome measure was the performance of the model when compared to calculated IBWCreation of the charts for the validated modelFollowing the validation of the model, a chart was created that could be used by clinicians to estimate IBW using the modified Mercy method.Demographic dataThere were 13,134 children in the pooled database. Of these children, 1,318 met the criteria for the weight estimation accuracy component of the study . There were 616 males (46.7%) and 702 females (53.3%). The rest of the demographic and anthropometric data are summarized in Table TBW and IBW performance dataThe bias, precision and accuracy data of the Mercy method in predicting TBW and IBW in this study population is shown in Table Obesity identification accuracy dataThe sensitivity and specificity of the model used to predict obesity (a TBW >120% of IBW) is shown in Table Chart for clinical useThe chart with the predicted IBW for each HL, as well as the cut-off values for TBW at which IBW should be used, are shown in Table Ideally, a weight estimation system should be able to provide an accurate estimation of both TBW and IBW in obese children to allow for appropriate and accurate drug dose calculations . The MerThere are several other systems that have been evaluated for emergency estimation of IBW in obese children, with which to compare the performance of the novel Mercy method. Age-based formulas, despite speculation by some authors that they might be accurate, have proven to be poor at estimating IBW in obese children . These formulas could not achieve a p10 of more than 50% (compared to the modified Mercy method in this study of just below 70%). Age formulas also had a high critical error rate of around 20%, compared to the 5% of the modified Mercy method. Given the poor accuracy of age formulas in predicting TBW and IBW, they should not be used . The BroThe ability of this model to determine when IBW should be used  was good in children over the age of two years, and very good in children over the age of five years. This aspect (the accuracy of identification of obesity) has not been evaluated in any previous weight estimation system. The sensitivity and specificity of the model are similar to those in other models used to predict obesity in body composition studies . Future There are some potential limitations to using the Mercy method in emergency care. Firstly, the correct use of the Mercy method - and therefore its accuracy - is highly dependent on the appropriate training and experience of the users . SecondlLimitationsThis study was performed in part of the dataset that was used for the development of the Mercy method originally. For this reason, the TBW estimates may be slightly more accurate than may be expected in other study samples. This should have a much smaller impact on the IBW model developed in the current study. In addition, since a large proportion of the study sample was comprised of children over the age of 10 years, the overall performance data may appear more favourable than it would be when the method was used in younger children. Finally, although virtual studies performed in databases have been shown to be valid, the accuracy of the IBW predictions will need to be established in future prospective studies .These findings advance the understanding of the methods of estimation of IBW in children when it cannot be calculated electively. This study established that the Mercy method can be modified to provide a reasonably accurate estimation of IBW in obese children, with very few critical errors. This modified Mercy methodology was substantially more accurate than age-based formulas, but was less accurate than the Broselow tape and markedly less accurate than the PAWPER XL tape, according to data from previous studies. Since the Mercy method is able to predict TBW significantly more accurately than age-formulas and the Broselow tape, its use would be recommended over these methodologies and could be considered as an alternative to the PAWPER XL tape if the tape was not available. This was the first study to evaluate the ability of a weight estimation system to predict in which children the use of IBW should be considered, for hydrophilic drug dose calculations. The ability of the model to accurately identify the obese child was reasonable, but additional work in the future would be required to refine this methodology.


A 9‐month‐old baby presented with sudden inability to stand and unable to move his leg. Clinical examination showed edema and knee effusion. Blood tests and MRI confirmed septic knee arthritis without bone involvement. He was treated with arthroscopic lavage. He had a complete recovery and normal growth. Appropriate evaluation of clinical and laboratory findings combined with the MRI results in accurate diagnosis of septic arthritis in infants. Arthroscopic management is a convenient method, leaving a minimal scar. Prompt diagnosis is obscure in infancy. Babies are unable to point or localize their tendency. The main manifestations are the sudden onset of refusal to bear weight on the leg, the painful decreased mobility of the joint, the general irritability of the infant with concomitant signs with fever, sleep disturbance, and reduced appetite. In the clinical examination, there is joint effusion that is tender on palpation. It must be differentiated from other disorders like Lyme arthritis or trauma. If left with delayed diagnosis and treatment, severe deformities with a permanent lesion of the cartilage and deformities may follow. Diagnosis is supported with radiological examination with x‐rays and MRI investigation.Appropriate treatment is urgent with surgical drainage of the joint, cultures for bacteria, and administration of antibiotics. Surgical treatment as an urgent procedure requires arthrotomy of the joint, thorough washing and in case of osteomyelitis drilling of the affected metaphysis. While arthroscopic washout is a regular procedure for adolescents and adults regarding the early management of septic arthritis, it is only recently becoming common in the pediatric population. The arthroscopic procedure was exceptional for infants, requiring small instruments and skills for the surgeon.We present a 9‐month infant that was diagnosed with septic arthritis of the knee and was arthroscopically treated.2A 9‐month infant was referred to in our pediatric orthopedic department with acute symptoms during the last 2 days refusing to bear weight on the left leg. The infant had almost 3 weeks since he started to stand up. The parents informed us that the day before he had a fever of 38°C, but the day of the first examination the infant was afebrile. There was markedly reduced mobility of the left leg when in the supine position, with the continuous kicking off the right leg and reduced movements of the left leg Figure Clinical examination of the hip joint revealed a full range of movements, without any discomfort. Minimal edema of the medial knee joint area appeared, with discomfort when flexing and extending the knee. Immediate x‐ray was performed to rule out a fracture. X‐ray was normal without signs of periosteal elevation. Ultrasound of the hip was normal without elements of joint effusion. The ultrasound of the knee joint showed edema of the muscles, with joint effusion. Blood tests showed increased CRP and ESR. Neutrophils and platelets were increased. We performed blood cultures that were reported later negative Table The infant had an MRI examination, under sedation. An extensive pathologic amount of fluid is observed in the left knee joint, with the involvement of the suprapatellar bursa. The finding is accompanied by the edematous appearance of the muscles around the joint , with a small amount of fluid in the intramuscular spaces. The lesions demonstrate intermediate to low signal intensity in T1W sequences and inhomogeneous high signal intensity in STIR sequences, without evidence of concomitant tumefactive lesion. There is no apparent edema of the bone marrow of the joint. The imaging findings in comparison with the clinical and laboratory findings mostly favor the diagnosis of septic arthritis, excluding evidence of osteomyelitis Figure Based on clinical, radiological, and laboratory examination, the infant was scheduled for knee arthroscopy. The infant was placed in a supine position. A standard anterolateral portal was established to introduce the 2.7 mm 30° arthroscope into the joint. An additional anteromedial working portal was performed. Introducing the scope in the joint, pus was pouring out from the cannula. That was sent for culture and microscopic analysis. The inflow of the pump was set to 30 mm Hg. A thorough lavage with 4.0 L of saline and inspection of the joint was followed. For the debridement of synovium remnants, a non‐traumatic 2.00 mm shaver was used. Joint examination revealed intact cartilage, meniscus, and cruciate ligaments, without signs of perforation from the metaphyseal area. Histological specimens from the synovial tissue were taken for examination. The procedure was completed in 20 minutes. We did not use drain because of the immediate and thorough lavage of the joint Figure The infant started immediately after the arthroscopy in intravenous antibiotics, with vancomycin. Cultures from the pus were negative for gram‐positive and ‐negative bacteria. Microscopic examination of the pus showed increased number of leukocytes . The pathological examination of the specimens confirmed the diagnosis of septic arthritis. There were specimens of the synovium with newly formed capillaries having hypertrophy of the endothelium. There were dense infiltrations exclusively with neutrophils.A cast was used to immobilize the knee and relieve the infant for a week.The infant had an immediate improvement in the clinical picture. In a week, he started standing on the affected leg even with the cast. There was an elimination of the edema, full range of knee movements in 2 weeks. Blood tests were performed with week intervals, with continuous improvement of CRP and ESR Table We stopped the iv antibiotics in 2 weeks and the infant started on oral antibiotics (amoxicillin clavulanate) for another 2 weeks. His blood tests were in normal values, and we stopped the use of antibiotics.Six months later, the toddler is normally walking. He has normal blood tests. He remains in clinical evaluation in 3 months intervals. Scars for the portals are minimally visible on the knee.3Acute bacterial arthritis of the knee is a severe disease, and early diagnosis is essential to provide immediate treatment. Sequences from delayed diagnosis and inappropriate treatment have severe effects with cartilage and joint destruction and growth disturbances of the affected leg.Septic arthritis in an infant always creates difficulties for the proper diagnosis. Inability to stand on the affected leg, discomfort, fever, irritability, and reduced mobility are the main clinical characteristics, but other diseases like an injury, a fracture, a Lyme monoarthritis, or a tumor may appear with the same clinical symptoms. Laboratory investigations including ESR, CRP, white‐blood‐cell count both peripheral, and synovial are helpful but none of them is diagnostic for septic arthritis.In children younger than 2 years with a history of fever, painful and reduced range of knee movements, and increased CRP >4 mg/L, diagnosis of septic knee arthritis is highly predictive.Predictors for the septic hip arthritis do not accurately apply for the knee. Obey et al used Kocher's criteria in a cohort of 104 patients with a mean age of 8 years (0.1‐18.9 years). They report that 52% of patients could have missed the diagnosis. The sensitivity is increasing to 72% by adding an increase of CRP. They report that only 31.7% of patients had knee pain with reduced flection and extension of the knee.Arthrocentesis is used in knee effusion to perform cultures and examine the cells and IgG titers. Arthrocentesis of the knee joint is not easily accepted from young patients and in infants a type of sedation is commonly required. In a series of 189 patients younger than 18 years that arthrocentesis was initially performed, a high percentage of Lyme disease was diagnosed (140 patients). For the remaining 49 children that were diagnosed with septic arthritis of the knee, only 23 had positive bacterial cultures while the remaining were negative. All children with a diagnosis of septic arthritis had an urgent surgical incision for drainage of the knee joint. But in some children that were finally diagnosed as monoarthritis, the surgical procedure was unnecessary.It is important to establish an accurate diagnosis to avoid unnecessary operations. The diagnosis and treatment are challenging in infants because of nonspecific clinical symptoms and laboratory findings.Negative bacteriological cultures in joint aspiration are not uncommon in infancy. In a series of infants <3 months, in 70% the cultures were negative. Saadi et al, report that 38% of patients had a true pathogen recovered in synovial fluid aspiration. In infants, staphylococcus remains the most common bacteria and thus despite that, the infant in our case had a negative culture, we administered vancomycin immediately after arthroscopy.Radiological examination is essential to exclude a fracture as a cause of the initial inability to stand with discomfort during movements. Ultrasonography is helpful revealing knee effusion but is not diagnostic. Magnetic resonance imaging is now easily accessible in all referral major hospitals. It requires sedation in infants but it has high accuracy. It can be combined with arthrocentesis at the time that the infant is in the examination area, sedated. Combined with the laboratory findings, it can provide high accuracy in diagnosis. Septic arthritis is characterized by joint effusion, with muscle involvement with edema. Most important is the exclusion of possible concomitant osteomyelitis in the metaphysis. In the presence of metaphyseal involvement, drilling of the bone is required. The periosteum may appear elevated in cases of infection or tumor. Tumor‐like involvement, like Ewing sarcoma or osteosarcoma or infantile types of leukemia, presents with chronic clinical signs and MRI findings show diffuse endosteal involvement with obscure limits, with extraperiosteal involvement. Rosenfeld et al suggest performing MRI, to exclude adjacent infections in cases of septic arthritis in children. Gibian et al analyzed 120 children over 6‐year period and underline the importance of immediate MRI imaging in increased CRP and older patients that are more likely to have osteomyelitis.In our infant, the early MRI investigation confirmed septic knee arthritis and the absence of osteomyelitis.With the diagnosis of septic arthritis, urgent surgical drainage is essential. This was usually performed with an incision opening the synovium and lavage of the joint. It is impossible to inspect the whole knee joint with a parapatellar incision.Arthroscopic lavage of septic arthritis of the knee in adolescents and adults is nowadays the method of choice. Since the development of small instruments, we can scope small joints of the hand and foot as well as peculiar joints like sternoclavicular or mandible joints.Arthroscopy in infants requires appropriate small instruments but is superior to surgical incision since it permits easy inspection of the whole knee joint to exclude areas of cartilage destruction and possible osteomyelitis lesions that communicate with the knee joint. Introducing the scope in the joint, we performed examination and culture of the fluid. We performed biopsy of the infected synovium. Arthroscopy can be repeated easily in cases that infection insists or remains. Two minimal scars are left as signs of the procedure compared with the scar from arthrotomy that is commonly spreading in young children as it is perpendicular to the skin lines of the knee.Arthroscopic treatment of septic arthritis in very young children is recently becoming popular. In a report of 24 children younger than 6 years, including nine knees with septic arthritis, the results were very encouraging without any complications from the procedure in the knee and no relapses. They were using a 3.5 mm arthroscope except for the ankles and a 3 weeks old baby for shoulder arthroscopy that they used a 2.7 mm arthroscope. Irrigation was performed with an adequate amount of saline.Comparing the arthroscopic lavage with an open arthrotomy, for septic hip arthritis, in older children, the results were similar, in a prospective randomized study.Arthroscopic treatment for septic arthritis for the knee had a success rate of 94% in a series of 56 children, with a minimum of 2‐year follow‐up. Six of them were younger than 1 year. Children had initially a knee aspiration under anesthesia, and when the macroscopic examination of the fluid was confirmed, they were immediately treated with arthroscopic lavage with a 5 mm arthroscope. Bacteriology was positive in 27 cases (48%). They used a drain for a mean time of 5 days (1‐9). They refer to two cases of in‐hospital recurrence that was similarly treated with a new arthroscopic lavage, and they have not performed any arthrotomies.Johns et al report a study of 24 patients over a 20‐year period, with acute knee septic arthritis. 11 patients received arthroscopic irrigation and 13 an open procedure. One 6‐month‐old baby is the youngest that was treated with arthroscopy, while a 2‐month old is the youngest of an open one. They used a 2.7 mm arthroscope for the smallest children. Five patients required a second procedure in the open procedure group compared with none in the arthroscopic group. They report no differences in the long‐term follow‐up.The impact of a procedure with two minimal portals is better than an open surgical arthrotomy in an infant that suffers the minimal trauma possible.None of the authors has any conflict of interest.NL: is responsible for writing and editing the original draft. CC and NL: performed surgery and are responsible for the investigation and collection of data. KP: is responsible for the data collection and assisting in editing. LG: is responsible for radiological investigation.Full consent has been given by the parents for publication of the case report.Video S1Click here for additional data file.


In this paper we present a new technique for a fiber-based temporal super resolving system allowing to improve the resolution of a temporal imaging system. The proposed super resolving concept is based upon translating the field of view multiplexing method that is used to increase resolution in spatial imaging systems from the spatial domain to the temporal domain. In this paper, an optical realization of our proposed system is presented, using optical fibers and electro-optic modulators. In addition, we show how one can apply this method using low-rate electronics for the required modulation. We also show simulation results that demonstrate the high resolution accepted in our method compares to the basic temporal imaging system. Experimental results which demonstrate resolution improvement by a factor of 1.5 based on the proposed method are presented together with an additional experiment that shows the ability to generate the desired modulation with low rate electronics. The process of encoding is also called multiplexing and many configurations were developed to present time-multiplexing4, wavelength multiplexing5, polarization multiplexing8, field of view (FOV) multiplexing11, and more. The field of transforming data processing capabilities from the spatial domain towards the time domain has also become common due to the simplicity in converting the temporal spectrum into space13.The topic of spatial super-resolved imaging has been highly investigated both from a scientific point of view as well as due to its applicability based prospective. There are various super resolving configurations developed in the field of spatial optical imaging. Generally, the idea is always to encode the spatial data in a way that will convert the high spatial resolution to some other domains such as time, wavelength, polarization, etc., then one can transmit the encoded data via the resolution limited imaging system and eventually to perform digital decoding15. This analogy led to the development of a time lens, which is an optical component that enables to extend and compress temporal optical signals while preserving its overall profile18, and so it enables to extend events in time and investigating them more efficiently. An optical time-lens may be realized in different ways such as by using the four-wave mixing (FWM) effect20, ultra-short temporal shutter which acts as a temporal pinhole camera22, or by using an electro-optic phase modulator (EOM)18.The analogy between the diffraction of light in space and dispersion of pulses in time has been known for many years23 to be proportional to the optical wavelength and the F-number of the imaging system and was later mathematically supported by Lord Rayleigh24. Based on a similar concept, the temporal resolution was defined in previous works to be the shortest transform-limited Gaussian FWHM pulse-width that we get in the output of the lens after inserting a Gaussian pulse in it25. Because of this resolution limitation, temporal super-resolution methods have been proposed such as a method that is based on localization microscopy algorithm26, time lens array imaging27, and a method that is inspired by structured illumination microscopy28.Since there is an analogy between spatial imaging systems and temporal imaging systems, the optical time-lens has resolution limitation associated due to its limited temporal size similar to the resolution limitation of the spatial lens. Spatial resolution limitation was first analyzed by Ernest Abbe29 might be limited for fundamental reasons and polarization multiplexing might be problematic for realization since fiber-optics systems are commonly using fibers which do not maintain the polarization state. Thus, one of the most suitable super resolving concepts as being well-matched to the time domain might be the FOV multiplexing super-resolution approach, which using fixed generalized gratings in predetermined positions9. Note that applying this concept in the case of spatial imaging is possible both when using coherent as well as an incoherent type of illumination.Because of the similarity between time and space, similar super resolving concepts being so nicely implemented in the spatial domain can be adapted to the time domain. However, usage of time multiplexing super-resolution concepts for temporal signals9 from the space to the temporal imaging domain. For that purpose, we use temporal gratings which are the temporal analog to the diffraction optical grating in the spatial case. Similar to the space grating, that generates a replica of the input field in the spatial frequency domain, the temporal grating generates a spectral replica of the temporal signal in the frequency domain30. It was shown that such gratings can be realized by using electro-optic intensity modulators31. The full description of our proposed super-resolved imaging system will be presented in the Methods section, along with a detailed explanation of how to implement the temporary gratings using low-electronics devices and integrate them into the proposed system. Then we show simulation results that demonstrate the high resolution accepted in our method compares to the basic temporal imaging system. This paper also presents preliminary experimental results which demonstrate resolution improvement by a factor of 1.5 based on the proposed method, and additional experimental results that show the ability to generate desired temporal grating with low-rate electronics. Finally, we will discuss the meaning of the obtained results and future possible research directions.In this manuscript, we will show how one can adapt the FOV multiplexing super resolving concept of Ref.16. The schematic diagram of this system can be seen in Fig. We first introduce the basic configuration for the temporal imaging system using a temporal lens based on an electro-optic phase modulator. The system consists of dispersion fiber with a length of mentclass2pt{minim16:If the optical waveform of the input is shorter than 16 since the quadratic approximation of the phase modulation is true only for such short pulses. This finite temporal aperture limiting the temporal resolution of this imaging system. To overcome this resolution limitation, the super-resolved imaging system follows the schematic sketch appearing in Fig. The temporal length of this time lens  equals at most to entclass1pt{minimaAs can be seen in Fig. mentclass2pt{minimBy using the analogy between spatial imaging and temporal imaging, the propagation of the temporal input signal through all the above- illustrated setup can be mathematically formulated. The full mathematical development describes this signal's propagation is shown in the first part of the Supplementary document of this paper. The accepted output signal will be:The expression in Eq. 6 is a super-resolution expression as the temporal spectrum is multiplied not by the temporal rectangular aperture, but rather by a synthetically extended temporal aperture. This aperture is continuously extended if we fulfill: When the above-mentioned condition, of n equal to –m does not happen, then we have in the integral of Eq. 5 a quadratic phase factor that multiplies the spectrum, and which is not canceled. If we observe again the expression of Eq. 9. Figure The first two terms cancel each other. The fourth term is a phase that does not depend on the spectral or the temporal coordinate and thus the interesting term is the third one. Having the temporal spectrum multiplied by such a term causes the temporal signal to be shifted in time by the amount of Therefore, this will lead to a restriction on the input signal to be time-limited . The worst restriction on the temporal length of the signal is when (n + m) = 1 and then the signal is restricted to a temporal length of:Thus, if the temporal input signal fulfills this relation then the ghost terms that do not have the super-resolution condition, do not interact with the super-resolved term (the super-resolved reconstruction) for which (n + m) = 0.To obtain a super-resolution by the method proposed in this paper, the generation of short temporal pulses is necessary. As we proved in our mathematics, the final super-resolved outcome equals to the temporal resolution of the encoding sequence. Therefore, the super-resolution factor depends on how short the pulses are. Thus, it is essential to have an all-optical scheme capable of providing such short pulses.To obtain a super-resolution by the proposed method, the temporal gratings in which we use should have temporal periodicity which is a low rate, i.e. not faster than the bandwidth of the time lens modulator. But each period of the temporal grating should have high temporal frequency  of the probe due to the stimulated emission-depletion effect (existing in fluorescence). This narrowing produces higher spatial frequencies and yields super-resolved image quality. What we propose here is to use a similar concept for realizing temporal grating having low-frequency temporal periodicity but high temporal frequencies within each of its temporal periods. The proposed idea is illustrated in Fig. To do this, we aim to implement an all-optical way of realizing such gratings while bringing to the field of temporal optics terms taken from the field of non-linear (fluorescence-based) super-resolved spatial imaging. In spatial optics, the usage of nonlinear effect as the one existing in fluorescence motivated the development of various super resolving concepts, where the most common are the STED1 and λ2 respectively, where the pump is much stronger than the probe. We intend to use a 1-D donut-like pump signal (looks like a Gaussian with a dip in its center) and a Gaussian-like probe. The two signals are synchronized in time in such a way that the temporal position of the probe is exactly at the temporal position of the dip of the pump. The non-linear effect used in our case will be the non-linearity of a gain medium. We will insert those two waves into a gain medium (e.g. Erbium-doped fiber amplifier), and since the pump is much stronger than the probe, it sets very low gain at the small intensity values of the probe  and high gain at the high values of the probe . Thus, the pulse shape of the probe is being deformed and it narrowed in time while leads to an all-optical generation of higher temporal frequencies. A full description and mathematical analysis of this method and for the way it can be combined into our proposed super-resolution system are shown in the third section of the Supplementary document of this paper.We propose to couple into one fiber two laser sources: probe and pump with slightly different wavelengths λTo validate the mathematical theory presented in this manuscript, we have constructed a MATLAB based simulator. In our simulations, we intend to show first the basic temporal imaging concept and then to add our super resolving concept. The simulation results can be seen in Fig. 22, where in Fig. 1 = 30 km and z2 = 30, 60 and 90 km for three different values for temporal magnifications M = 1, 2 and 3 respectively. Those different scaling factors are indeed seen in the results of Fig. 0 = 4 km, z1 = 30 and z2 = 30 and 60 km for two different values for temporal magnifications M = 1 and 2 respectively. A temporal grating with frequency Figure As we mentioned above, the super resolving is dependent on how many non-zero The simulation results show that the suggested grating improves the temporal resolution compare to the basic imaging setup. With this grating, each pulse in the output has temporal width of 55 ps, while in the basic imaging system we get 85 ps for each pulse, so this grating could serve us in demonstrating the resolution improvement cause by our proposed technique.To simplify the experimental setup, two separates experiments were performed, one for demonstrating the principle of the new super-resolution method, and another experiment that shows the ability to generate a train of temporally narrow pulses. In the first experiment, we used the simpler temporal grating that consists of a summation of two sine waves as we saw in the previous section, instead of using the short pulses train.3 optical intensity modulators, use Mach–Zehnder interferometer (IOAP-MOD9140-F-F-1 of JDS Uniphase), which function as temporal gratings. The pulse was modulated at frequencies of 2.5 GHz and 7.5 GHz. A Network analyzer (N5230A PNA-L of Agilent) was used as a signal generator to modulate the 7.5 GHz frequency and another signal generator  was used for the 2.5 GHz modulation. Then the pulse was dispersed again through 30 km fiber with a dispersion coefficient of The purpose of the first experiment is to demonstrate the capabilities of the proposed system illustrated in Fig. To investigate the accepted temporal resolution in our scheme, compared to the temporal resolution of the basic temporal imaging system, the output pulse was detected for two cases: with modulation (our scheme) and without modulation (standard imaging system). The detection was performed by a sampling scope with a temporal resolution of 1.22 ps. The detected pulses for both cases can be seen in Fig. The modulated output signals were analyzed by the MATLAB code presented above. The pulse without modulation was inserted into digital pulse imaging (pulse width of 30 ps) and additional 34 km dispersion while the modulated pulse was inserted into digital analysis including pulse modulation for imaging (pulse width of 30 ps), additional dispersion of 30 km, temporal grating that consists of two sine waves, similar to the grating that was used in the experiment, and negative dispersion of 4 km. The dispersion coefficients for all the fibers in the simulation were The results of the digital analysis of the measured signals can be seen in Fig. The second experimental setup was designed to demonstrate the ability to reduce the duration of optical pulses by using the method illustrated in Fig. A pump wave with a wavelength of 1530 nm and a probe with a wavelength of 1546 nm were modulated and were insert into one fiber by using an optical coupler. The shape modulation of each signal can be seen in Fig. The coupled signal was inserted into an EDFA. The intensities of the pump and the probe were chosen such that the pump intensity was seven times larger than the probe at the amplifier input. Then the pump and the probe were separated by using Arrayed Waveguide Grating (AWG), and the output probe was detected. The output probe compares to the input probe can be seen in Fig. It can be seen that by using our proposed technique we could shorten the probe by factor 2. As we mentioned above our end goal is to generate a pulse train ,which its frequency of the should be lower or equal to the frequency of the time lens  information is needed, i.e. amplitude and phase. In our numerical and experimental examination, we injected signals having only amplitude modulation and a constant phase. Indeed, when propagated through the system itself the signal gains phase but if the encoding pattern had no phase information then amplitude only decoding pattern would be able to fully reconstruct the super-resolved information. We have proved it before in our former research as e.g. seen in Ref.In this paper, we have presented the conceptual methodology as well as the realization design of a novel temporal super-resolved imaging system. We showed that by using low rate electronics to implement a time lens modulator or used for the generation of a train of low-resolution temporal pulses , one can transmit a temporal signal and recover it a temporal resolution higher than the bandwidth of the time lens and of the temporal gratings . The proposed optical realization is based upon common optics communication components and does not require high-cost equipment.Mathematical analysis, as well as numerical simulations, proved the proposed novel operation principle. Primary experimental were demonstrated resolution improvement by a factor of 1.5 based on the proposed method and additional experiment showed the ability to generate the temporal grating which is required for our new method. As part of our future research, we intend to experimentally validate the presented concept.See Supplement Supplementary Information.


There is a need to understand the perceptions of healthcare workers towards its practice and the use of alcohol-based hand rubs (ABHR) to make recommendations to promote HH. Our study aimed to explore the perceptions of Nigerian healthcare workers towards HH and the use and availability of ABHR to suggest potential interventions to improve its practice as qualitative evidence in this field is limited in Nigeria.a qualitative study design was utilized to understand the perceptions of healthcare workers towards HH and the use of ABHR at Adeoyo Maternity Hospital, Ibadan, Nigeria. Purposive sampling was used to recruit nineteen healthcare workers who were interviewed. Thematic content analysis was used to analyze the data generated.five themes emerged including discrepancies in what constitutes HH practice as participants, motivation for HH practice, a good knowledge of timing as regards practice, barriers to good practice and evidence of poor practice.while many healthcare workers know about HH and self-reported compliance towards it seems to be high, knowledge gaps, lack of resources, absence of regulations and poor working conditions were impediments to the successful implementation of HH practices. We recommend that hospitals institute well-articulated HH regulations, continuous education and training of healthcare workers. Hospitals should also ensure adequate provision of resources for hand hygiene and institute a continuous monitoring and feedback program to evaluate compliance with regulations. Despite supporting evidence on the importance of effective and consistent hand hygiene (HH) practices as simple measures with proven effectiveness in reducing the spread of healthcare associated infections (HAIs) ,2, thereStudy design: a qualitative study design was employed to explore a phenomenon rather than begin an inquiry from a hypothetical set of facts, from first-hand accounts of the experiences of the participants in the field of interest in order to derive knowledge and understand meaning.Setting: the setting of the study was Adeoyo Maternity Hospital (AMH) in Ibadan, Nigeria with a population of 5.5 million people. Founded in 1927, the hospital has a children outpatient department, obstetrics/gynaecology wards, a children´s ward, and a casualty department. Despite being a secondary hospital, approximately 3000 deliveries are carried out yearly [t yearly .Sampling approach: a purposeful convenience sampling method was adopted in the selection of participants. This study set out to have a sample size of 20, with each interview to last between 20 and 30 minutes. Only 19 interviews could be done because of an industrial action which greatly affected the number of participants that could be recruited.Participant recruitment: a formal introduction was made to the head of the hospital and other senior doctors and nurses. Participants were HCW including nurses and doctors (18 years or older) in regular physical contact with patients who were not on vacation, or on an extended period of leave during the time of the interviews. Doctors and nurses in the obstetrics/gynaecology, paediatrics and the outpatient departments of the hospital were then approached and informed of the study by means of a participant information sheet (PIS). Appropriate verbal explanation of the content of the PIS was also provided to potential interviewees and dates were scheduled for the interviews. Participants were given time to understand the content of the PIS and to ask questions. Some of the interviews occurred on the same day that the participants were made aware of the study, others were scheduled according to their convenience.Data collection: data collection was carried by means of semi-structured interviews to collect meaningful information on the experiences of interviewees about HH and the use AHBR. The interview explored four main areas: cues to performing hand hygiene, availability and use of ABHR, interpersonal dynamics and context. Before the interviews were conducted, informed consent was obtained from participants.19 key informant interviews were conducted on wards, clinics and offices between June and August 2017. The duration of the interviews ranged from 16 minutes to 38 minutes. The recording was done with a Samsung Galaxy tab which had an audio recording application and transcription was done verbatim by the research team. The total interview time for the research was 8 hours, 7 minutes and 39 seconds and a total of 58,593 words were transcribed verbatim from the audio-recorded interviews. Ethical considerations: ethical approvals were obtained from the Oyo State ethical review board and University of Liverpool ethical review boards. Participants were briefed on the nature of the research and what was expected of them and were given the opportunity to withdraw from the study anytime they wanted without any repercussions. They were assured of anonymity and confidentiality. Data was kept in a password protected computer hard drive and anonymity was ensured by replacing their names with a number in the transcripts.Data analysis: data analysis was done using thematic analysis with data analysis roughly followed 6 phases; from familiarization of the data through transcription, generation of initial codes from the transcripts to generation of themes and producing results.Key findings are summarized in This theme comprises of several sub-themes including good HH performance, options for HH and use of ABHR.Good performance: all the participants considered their practice of HH and that of the hospital staff in general, to be above average. One of the participants, while acknowledging that he could be carefree, still considered his adherence to be well above average. This high appraisal of the self-performance was, for many, higher than the perceived general rate of performance in the hospital, which was also often above average. Although all participants had been assured of confidentiality the body language of a few of them, especially the nurses, suggested a desire to give an impression that all was well. P11: “...my personal one (rate of hand hygiene), I´ll say it´s hundred percent.”Options for hand hygiene: all participants had a general idea of the available options for HH, but there were differences in what these were. They all considered the use of soap and water and ABHR as options but did not have much to say about the effectiveness of one over the other. Also, very few talked about a distinction in the type of soaps to be used; antiseptic or plain. P1: “The best way is to use soapy solution under running water...but in a situation where the water or soap are not available we can opt for hand sanitizers...Yes antiseptic soap is proper but here we don´t use it, I must confess we don´t use antiseptic soap here, it´s just ordinary liquid soap.”The use of alcohol hand sanitizers: there were different ideas about the role of ABHR in HH. There was an understanding on the part of some that it could be used in place of water if the hands were not very dirty, while others thought it was to be an adjunct to regular washing with soap and water and not necessarily to be used alone. P12: “After washing we sanitize our hands. ”Also worthy of note was the fact that most of the participants appeared not to have considered the importance of the quantity of ABHR which needed to be used in hand hygiene. Only P15, who was a nurse in the theatre, said the quantity should be enough to be rubbed up as far as the elbows.Some inherent factors that seemed to encourage the practice were revealed in this theme and resulted in the following sub-themes.Increased awareness: the recent increase in awareness of HH practice in the last couple of years was a subtheme that re-echoed from many of the participants as a cause of an increase in HH practice. A major factor responsible for this was the episodes of disease outbreaks in the country. P8: “But I think awareness about hand hygiene has increased after that Ebola outbreak and in this hospital, I think, you want me to give you figure as well?”Influence of disease outbreaks: this subtheme was developed as responses from several participants showed lingering consciousness of the outbreaks of viral hemorrhagic fevers. The most notable example cited was the 2014 outbreak of ebola virus disease. This influence of disease outbreaks was seen in the practice of HH in general and in the use of ABHR in particular. Indeed, P6 had never known about ABHR before this outbreak and thought that it only came into use in its aftermath. P6: “Well, the alcohol hand sanitizers...I know it came into (widespread use in) this country basically after the ebola outbreak...that´s when the federal and state governments made it available...for everybody, for all the hospitals in Oyo State.”P9:”...hand hygiene practice was, very low but, immediately after the epidemic of ebola, the level was high, presently it´s getting low again.”Prevention of infection: while all the participants were mindful of the role, they played in preventing the spread of infections to patients they attended to, some were also concerned about contracting infections from patients. Three of them expressed concerns of not transferring infections to their children at home. P10: ”I don´t want to transfer germs to my patient because they´re the main reason why I´m here in the first place. I want to protect myself, I want to protect my family.”A part of routine: HH was seen as an innate part of medical or nursing practice, having been learned during the training of the health care professionals. The participants felt it was something necessary in the routine of patient care. P11: “In the profession you know before you do anything you have to wash your hands. It is something that is registered.”Developed as a direct response from questions that were asked, it was adjudged a theme because it tested participants knowledge of the WHO initiative, “My five moments of hand hygiene.”Hand hygiene before and after procedures: all the participants agreed on the importance of HH practice after medical or nursing procedures as means of curtailing the spread of infections. P6: “It´s important that at the start of seeing a patient hand hygiene is very essential. I think that just like I keep saying, in paediatrics before you touch a particular baby you go and wash your hands, after touching that baby you wash your hands whether that´s the only baby you´re seeing or that´s the last baby, wash your hands before, wash your hands after.”Hand hygiene after de-gloving: many of the participants considered HH after glove use as important. This subtheme was developed after repeatedly being seen among the participants. P1: ”It´s a policy here in this hospital before we examine any patient, we put on our gloves so after we have finished seeing the patient you remove the glove then you go ahead and wash both hands.”Hand hygiene after bodily fluid exposure: there was a unanimous agreement, on the side of participants, that HH after body fluid exposure was of utmost importance.This theme was developed as participants expressed frustrations, they experienced in the workplace which made the practice of HH difficult. Four subthemes were developed under this theme.Financial constraints: many complained of inadequate financing. This factor, which was seen not only in the area of hospital funding and procurement of resources but also in staff remuneration, was a common reason for poor practice. P6: “A lot of things are wrong, people are not happy, no salaries...so these are the issues.” P9: ”We complain but the management say there´s no fund. They´re telling the truth. The amount of imprest the hospital is given has been halved. Even that half is not regular.”Absence of regulations: all the participants responded in the negative when asked about of the presence of HH regulations within the hospital. P15: ”In terms of policy? No.”While many considered such regulations as realistic and did not mind its introduction, P4 did not think it would be easy for such to work without addressing other fundamental issues such as lack of amenities. P4: ”Well, it´s not really realistic in the sense that there are limitations to the rules, in each ward there is this handwashing procedure that is pasted on each wall. One of the things that affects that is that at times we might not have running water.”Lack of amenities: the sense of lack and disaffection with the work environment was portrayed in several ways such as frequent shortages in running water, power outages, a limited supply of ABHR and lack of disposable towels. P6: ”Well the rate in the hospital in general I would say well, it´s like 80%. Most of the time when you want to wash your hands and there´s no power supply to pump water, you get discouraged. So most of the time you just go away and probably assume that you are going to clean your hands when you get home and more so the alcohol hand sanitizers are not readily available in this environment, sometimes it´s even expensive and in a case whereby someone has not been paid, is that time you´ll go and use the little that you have to buy hand sanitizers?”Workload pressure: most considered the workload too strenuous to allow for adequate HH performance. This workload was expressed in both the number of patients´ participants had to attend to, the hospital being situated in a densely populated area and the limited number of staff there was to work. Participants often got so busy that they either forget or were unable to perform hand hygiene. P6: ”Well, most of the time, I see like 200 patients per day. I don´t know if it´s possible to wash your hands 200 times, so most of the time it´s not feasible. That´s the sincere truth. It´s either you´re finishing one examination, before you know it, patients they´re already queuing up and if you have to see 200 patients and one doctor that´s killing, so washing your hands 200 times is stressful.”Several instances of poor practice in relation to HH are discussed under two sub-themes below.Occasional failures to perform hand hygiene: on several occasions there was a failure to perform HH. Sometimes participants felt it could be delayed as they felt the successive use of gloves could obviate the need for performance. P3: ”Well, I´m in the outpatient section, I see a lot of patients and for every patient I wear a pair of gloves so if I have to wear a pair of gloves stand up wash my hands, come back, see another patient stand up, it´s not easy, so most times I just keep changing the pair of gloves. For every patient I wear a pair of gloves.” There was also the feeling that if a procedure was not strictly an aseptic one, there was really no need to perform HH. For example, the recording of vital signs such as pulse and temperature could be considered innocuous activities that do not require HH. P5: ”I think, if what you´re doing is not an aseptic procedure then you don´t have to wash your hands except if your hands are really dirty, .let´s say you´re coming from a place where not too long ago you washed your hands, you´ve not done anything with your hands, the next patient that comes in you want to examine the patient and you need to wear gloves to do that examination doesn´t mean that you have to wash your hands.”Poor practice in drying hands: all agreed that drying of the hands was an important part of HH when they were specifically asked and many felt that their practice of hand drying was inadequate. There was no adequate provision for hand drying even in places where a wash station was provided. The routine practice was to have a hand towel that was reused. Most were however loathed to admit to this practice of sharing towels and said they made use of their own personal hand towels why a few preferred to air dry their hands after washing. P8: ”In my practice here there are times...okay, I go around with my handkerchief as you can see I have...I have a number of them at home...I use them to dry my hands...in some places in the hospital some nurses or doctors provide handkerchiefs beside the wash hand basin. I don´t like it because people just come and use it, it may even cause more infection...so I will say dry your hands with a clean hand towel, preferably a personal one.”This study sought to understand the perceptions of Nigerian HCW towards HH and the use of ABHR. To the best of our knowledge, the study fills a gap in current research on the subject being the first qualitative study of its kind in the country. All the participants scored themselves high in HH performance. This high appraisal is in keeping with findings from previous studies which showed that healthcare workers often have a high estimation of their performance of HH and other infection control practices ,10. By rThis is in keeping with the work by Whitby where they found that HH habits are developed before adolescence and that by adult life most persons are already set in their ways . Also, wS. aureus transmission rates observed by Pittet [A common theme that was present throughout the study was the frequent lack of tools needed to carry out HH. Information and even motivation are not enough to ensure adequate HH practice if there are lack of tools, skills and strategies. Inadequate wash stations, frequent shortages in potable water supply and power outages often impeded practice. Such challenges are all too common and have been reported before. Segun reported lack of running water and non-availability of ABHR as reasons for poor HH in a teaching hospital in Nigeria . A ruraly Pittet  shows thIn conclusion, while many HCW know about HH and self-reported compliance towards it seems to be high, knowledge gaps, poor practices and inadequate ABHR use among HCW were observed. Lack of resources, absence of regulations and poor working conditions were impediments to the successful implementation of HH practices. We recommend for hospitals to institute well-articulated HH regulations and continuous education and training of HCW. Hospitals should also ensure adequate provision of resources for HH and institute a continuous monitoring and feedback program to evaluate compliance with regulations. Again, legislation mandating hospitals to set up infection control units with adequate budgetary allocation for their operations should be passed.Poor compliance of healthcare workers to hand hygiene practices in low- and middle-income countries;Lack of systems, poor infrastructure and limited behavioral change interventions are among that influence the poor compliance to hand hygiene.This study sought to understand the perceptions of Nigerian health care workers towards hand hygiene and the use of ABHR. To the best of our knowledge, the study fills a gap in current research on the subject being the first qualitative study of its kind in the country;Disease outbreaks were seen to influence the practice of hand hygiene in general and the use of ABHR;Although participants rated themselves high on the practice of hand hygiene, a substantial knowledge gap on hand hygiene practice was demonstrated in this study including variation in ideas about the role and use of ABHR in hand hygiene.