We report a case of accidental cutaneous burns caused by salbutamol metered dose inhaler. A 9-year-old boy underwent dental extraction at a children's hospital and was incidentally noted to have burn injuries on dorsum of both hands. On questioning, the boy revealed that a few days ago his 14-year-old brother, who is an asthmatic, playfully sprayed his salbutamol metered dose inhaler on the back of both his hands with the inhaler's mouth piece being in direct contact with the patient's skin. On examination, there was a rectangular area of erythema with superficial peeling on the dorsum of both hands, the dimensions of which exactly matched those of the inhaler's mouthpiece. It is possible that the injury could have been a chemical burn from the pharmaceutical/preservative/propellant aerosol or due to the physical effect of severe cooling of the skin or mechanical abrasive effect of the aerosol blasts or a combination of some or all the above mechanisms. This case highlights the importance of informing children and parents of the potentially hazardous consequences of misusing a metered dose inhaler. A 9-year-old boy underwent dental extraction at a children's hospital and was incidentally noted to have burn injuries on dorsum of both hands. Pediatric team was contacted to exclude nonaccidental injury.On questioning, the boy revealed that a few days ago his 14-year-old brother, who is an asthmatic, playfully sprayed his salbutamol metered dose inhaler on the back of both his hands with the inhaler's mouth piece being in direct contact with the patient's skin. The boy did not feel anything unusual immediately afterwards but noted redness in the sprayed areas the next morning. As the patient and his brother feared punishment from their mother, they did not tell anyone about the above.On examination, there was a rectangular area of erythema with superficial peeling on the dorsum of both hands, the dimensions of which exactly matched those of the inhaler's mouthpiece Figures  and 2. TOnce we were satisfied that this was an accidental injury, the pharmaceutical company which manufactured the inhaler was contacted. The pharmaceutical company was not aware of salbutamol causing cutaneous burn injuries. On reviewing the literature, a case of a 22-year-old asthmatic with history of mental illness presenting with self-inflicted cutaneous burn injuries due to salbutamol inhaler has been reported . A 14-yeIt is possible that the injury could have been a chemical burn from the pharmaceutical/preservative/propellant aerosol, due to the physical effect of severe cooling of the skin, mechanical abrasive effect of the aerosol blasts, or a combination of some or all the above mechanisms .It is important that children and parents be informed of the potentially hazardous consequences of misusing a metered dose inhaler.


The family members also utilized resources and support systems, such as their immediate families, mental health care professionals, and their churches.This exploratory research paper investigated the coping strategies of families of hospitalized psychiatric patients and identified their positive and negative coping strategies. In this paper, the coping strategies of 45 family members were examined using a descriptive, correlational, mixed method research approach. Guided by the Neuman Systems Model and using the Family Crisis Oriented Personal Evaluation Scales and semistructured interviews, this paper found that these family members used more emotion-focused coping strategies than problem-focused coping strategies. The common coping strategies used by family members were  Currently, there are over 57 million Americans (about one in four adults) who have a diagnosable mental disorder . StudiesCoping with a mentally ill relative can be difficult, and many families are being faced with the added responsibility of transitioning their relative from inpatient psychiatric treatment to outpatient treatment , 8. WithCurrently, families find accessing community mental health treatment services to be complex and wait times for services may be weeks or even months . Some faCurrently, many states are facing economic hardship, and budget reductions to mental health services have occurred. According to one survey, states spend less on mental health services now than they did in 1955 when budgets were adjusted . Since 2The impact of the unavailability of services is felt by families who have been given the responsibility of caring for their mentally ill relative after psychiatric hospitalization . With deThe term coping has several definitions ranging from the ability to deal with problems to, as Lazarus and Folkman defined it, a transactional process, which changes over time and within its situational contexts . PearlinMcHaffie viewed coping as an important concept of study in the field of nursing. The author stated that recognizing how well an individual copes, no matter how ill he is, will determine his psychological well-being . McHaffiHatfield and Lefley applied the concept of coping to mental illness. The authors examined how families cope with mental illness by doing what is necessary to survive through the use of adaptation and coping mechanisms . These aM. A. McCubbin and H. I. McCubbin viewed coping as part of their resiliency model. These authors viewed adaptive coping as a family strength and defined a coping behavior “as a specific effort (covert or overt) by which an individual  attempts to reduce or manage a demand on the family system” , page 22Lazarus and Folkman supported the view that even though stress is inevitable, it is the coping that makes the difference in adaptational outcomes. The authors' theory defined coping ability as one's response to a demand and not an automatic response to the environment . This thAccording to Lazarus and Folkman, coping has two major functions: (a) regulating stressful emotions or emotion-focused coping and (b) altering the distressed person-environment relation or problem-focused coping . EmotionProblem-focused coping strategies usually are used by adult individuals in work contexts, and emotion-focused coping strategies are used in health-related contexts . This shCoping strategies can be classified further as being positive or negative. Some family members use positive coping strategies to help them manage their situation, such as positive thinking and the utilization of appropriate social supports, which include family, friends, and the church –26. SomeCommunication is a coping strategy that family members use to share information about their thoughts and feelings. The social stigma of mental illness is seen as a deterrent to sharing information about their mentally ill relative outside the family. Concealment of the illness has been viewed as preferable to disclosure due to the risk of negative reaction from others . CommuniAcceptance is another emotion-focused coping strategy that family members may utilize to cope with their mentally ill relative. Acceptance is a form of cognitive restructuring where individuals appraise their thinking reactions to situations and change negative reactions to positive, or at least neutral ones . AcceptaThe use of cognitive distraction is also noted to be an emotion-focused coping strategy, which includes passive appraisal . CognitiSome families find it difficult to deal with the stigma associated with mental illness, and this negatively influences the coping ability of the family , 32. SomSome families use religious and spiritual support as a means for coping with caring for a mentally ill relative. The use of spirituality is seen as a positive emotion-focused coping strategy . SpirituFamilies use a variety of coping strategies and resources to maintain healthy family functioning . A vitalAs mental health treatment options decrease, families are being given the responsibility of transitioning their mentally ill relative from inpatient psychiatric treatment to outpatient treatment . The copThis exploratory research study used a descriptive, correlational, mixed method research design. This study explored the coping strategies, support systems, and resources of family members of hospitalized psychiatric patients. This design was used to determine if a relationship exists between family coping strategies and spirituality, ethnicity, gender, income, and family relation of the family members. This study used the F-COPES for the quantitative portion of the study and a semistructured interview for the qualitative portion of the study.The Neuman Systems Model of nursing provided the framework for this study , 36. TheThe basic structure of the client/client system is represented as a series of concentric rings or circles, which surround the core. The rings are divided into three different type lines: (a) the flexible line of defense, which represents the outer concentric ring (broken line) and which acts as a buffer system for the client's normal state; (b) the normal line of defense, which is the solid line that lies between the flexible line of defense and the internal lines of resistance and which represents the client's usual wellness level or steady state; (c) the lines of resistance, which represent the inner concentric circles (broken rings) and which contain internal and external resource factors which help protect the client against a stressor , 36.In the Neuman Systems Model, the environment is a key concept which affects the client system. The environment is defined as all the internal and external forces affecting the client positively or negatively , 36. ThiThe created environment acts as an open system that exchanges energy with the internal and external environment , 36. ThiThe Neuman Systems Model  was usedThe psychological client variable refers to the relationships and mental processes of the client system , 36. FamThe client reacts to the intrapersonal stressors that arise from the internal and created environment , 36. In In this exploratory research study, the following four of the client variables are represented by the appropriate theory concepts and were tested by the empirical indicators as follows: (a) psychological, which represents the coping strategies of family and was tested by the F-COPES and semistructured interview; (b) sociocultural, which represents the social and cultural supports of the family and was tested by the F-COPES and semistructured interview; (c) developmental, which represents the family's relation to the hospitalized mentally ill patient  and was tested by the background data survey (BDS); (d) spiritual, which represents the use of spirituality as a coping strategy and was tested by the F-COPES. In addition, the external environmental stressor from the mental illness of the relative is also represented on the following conceptual-theoretical-empirical structure.A convenience sample was used for this study. The intended sample was an adult individual who was a family member of a hospitalized psychiatric patient. A family member was considered as anyone who the mentally ill individual deemed to be family. The inclusion criteria for participation in this study were (a) an individual who was 18 years of age or older; (b) a family member of the hospitalized psychiatric patient, but who was less than 80 years of age; (c) a family member of any ethnicity, gender, and socioeconomic level; (d) a family member who was actively involved in the care of the mentally ill relative (at least weekly).The target sample for completing the surveys was 45 participants. This sample size was chosen so that there was at least 90% power to conduct both the descriptive and regression analyses. The F-COPES score was a primary outcome of the study and was expected to have the greatest variance; it was used as the basis of the sample size calculation.The setting for this study was a psychiatric unit of a hospital in the mid-Atlantic region of the United States. Approval to conduct this study first was obtained from the Hampton University Institutional Review Board (IRB) and then the IRB approval was obtained from the mid-Atlantic region hospital. After IRB approval was obtained, the researcher began to collect data at the hospital. Family members of the hospitalized psychiatric patient were asked to participate in this voluntary study. Family members were provided information verbally about the study upon admission and during visiting hours by staff. The principal researcher was available during visiting hours to recruit participants. This researcher was the only researcher collecting data. All participants were asked to participate in a semistructured interview in addition to completing the F-COPES survey.Informed consent was obtained from all participants, which included a statement regarding the confidentiality of the participants. The consent provided information on the name and purpose of the study and the possible risks and benefits of the study to the participants as well as information on the possible effects of the study on the fields of mental health and nursing. A copy of the consent form was given to each participant. The consent form was kept separate from the other data collection forms.The BDS was developed by the researcher to obtain demographic information. This information included questions regarding gender, age, ethnicity, income, and family relation. The BDS took approximately 5 minutes to complete. The Family Crisis Oriented Personal Evaluation Scale (F-COPES) was used to measure family coping. The F-COPES is a 30-item instrument, which is used to identify problem-solving and behavioral strategies used by families in crisis or problem situations  on with life.” Some of the participants articulated that the care of their mentally ill family member was their sole responsibility; there was no one else who could or who wanted to cope with the situation. The F-COPES does not assess for this attribute, but the semistructured interview questions identified this important theme. The participants also stated they were able to cope with caring for their mentally ill relative through the support of their immediate family. Many of the participants felt that their family was the only one who could understand what they were going through. Their responses were similar to the F-COPES data, which indicate that the participants coped by talking with their family. Another common theme noted in the responses of the participants regarding their ability to cope with their mentally ill relative was involvement in passive activities such as reading or watching television. These activities also were noted as common responses from the F-COPES data. Many of the participants felt these activities offered them the opportunity “not to think,” a passive activity allowed them to “relax” and “recharge.” A few of the responses from the participants regarding how they coped with their mentally ill relative were related to positive activities, such as exercising and staying optimistic. Some of the participants felt better when they were actively involved in their relative's care.To determine which common support systems were used by family members of hospitalized psychiatric patients, each subscale of the F-COPES was summarized. Per-item average scores in a domain greater than three indicated the domain was a support system used by the participants see .The support system most utilized by the participants was seeking spiritual support (Mdn = 4), which consisted of church involvement, seeking ministerial advice, and faith in God. The next highest reported support system used by the participants was mobilizing family to acquire and accept help (Mdn = 3.75), which included seeking help from similar families, community agencies, the family doctor, and professional counselors. The least reported support system used by the participants was acquiring social support (Mdn = 3.11) from friends, neighbors, and relatives. The semistructured interview question, “what support systems do you use to help you cope with your loved one?” helped identify the support systems of family members of hospitalized psychiatric patients. The most common responses from the participants were related to family. Most of the participants responded that their immediate families were their support systems. The church was identified as another important source of support for the participants. The F-COPES data found spiritual support as the most common support system used by the participants, but the interview responses identified the family as the major source of support. The interview also identified only a few participants who saw the physician and the counselor as forms of support.The participants' responses indicated that illness education was the most valuable resource they could have. This resource included information about signs and symptoms, relapse prevention, and medication. The second most common resource noted from the responses was the need for support groups. Most of the participants stated they never had attended one but felt it would be something that could help them cope with their relative. Another significant valuable resource for family members of hospitalized psychiatric patients was physicians and counselors. The semistructured interview question, “What do you think the mental health professionals could do to help you cope with your loved one?” addressed the family member's perception of the role of the mental health professional. The participants' responses indicated that the most common theme noted was information. The participants' perceived role of the mental health care professionals was to provide them with information regarding their mentally ill relative's condition, disease process, treatment, and rehabilitation. R2 for each of the demographic variables was so low, indicating a small level of explained variation across the categories of demographic indicators. Other variables that may lead to an increase in variability are other measures of class, such as educational level and occupational status. The relationship between ethnicity, gender, income, family relation, and coping of family members of hospitalized psychiatric patients was determined by a series of generalized linear models (GLMs). These GLMs were analyzed using the total coping score as the primary outcome. Crude effects of each demographic characteristic were determined in a univariate GLM where demographic variables were included as class variables due to the method of data collection. Individually, demographic variables did not have a significant impact on coping ability see . The R2P = .97), gender (P = .43), ethnicity (P = .49), relation (P = .83), and annual income (P = .95) were not statistically significant for this group.The demographic profile of participants with the lowest number of total coping scores (lowest 10%) and the highest number of total coping scores (highest 10%) were examined. A higher number of those aged 48–57 years old, males, African Americans, spouses and significant others, and with incomes under $50,000 per year were among the lowest tenth percentile in total coping scores. This lowest total coping score population was compared to the demographic profile of the overall study population using a Chi-square analysis. This analysis showed that age  and that age (P = .94), ethnicity (P = .25), relation (P = .75), and annual income (P = .89) were not statistically significant for this group.The analysis showed that only gender  was statistically significant  was found to be statistically significant. This finding may suggest that female relatives of hospitalized psychiatric patients may be able to cope better than male relatives. The results showed that the majority of family members of hospitalized psychiatric patients utilize some form of spirituality to help them cope with their mentally ill relative. The use of spirituality is an emotion-focused coping strategy . The famThe family members stated that they utilized a variety of support systems. The use of social supports is a problem-focused coping strategy . The datThe use of spirituality is an emotion-focused coping strategy that can decrease one's level of stress and increase one's level of well-being . This isIn the theory of coping strategies of family members of hospitalized psychiatric patients, the theory concept of family coping strategies represented the Neuman Systems Model psychological client variable. The common coping strategies identified were communicating with their immediate family members, acceptance of their situation, passive appraisal, spirituality, and avoidance. The theory concept of social cultural supports represented the sociocultural client variable. The common resources and support systems family members of hospitalized psychiatric patients used were illness education, mental health care professionals, their church, and increased finances. The findings did not show any relationship between coping and ethnicity. Family relation represented the developmental variable in the theory of coping strategies of family members of hospitalized psychiatric patients. The findings showed that family relation has no significant impact on the coping ability of the family member. Only gender  was shown to have some correlation to coping ability. The theory concept of spirituality as a coping strategy represented the spiritual client variable. This study's findings suggested that the use of spirituality may aid in the overall coping ability of the family member of the hospitalized psychiatric patient. These client variables are interrelated and interact simultaneously to help the family member of hospitalized psychiatric patients cope with external environmental stressors. The family member who is diagnosed with a psychiatric disorder is the stressor from the external environment. The external environment contains all the forces and influences that exist outside the client system , 36. TheThe coping strategies of family members of inpatient psychiatric patients were explored in this study. The use of emotion-focused coping strategies, such as communication with family members and cognitive distraction, were noted to be used more frequently and effectively than problem-focused coping strategies by family members of hospitalized psychiatric patients. The support of immediate family was seen as a vital coping strategy and support system when coping with their mentally ill relative. The family member's need for information is a major theme in the results of the semistructured interviews. The information is related to illness education, support groups, and the condition of their mentally ill relative. The family member's perception of the role of the mental health care professional also is related to the sharing of information. The family members felt that mental health care professionals should not only provide them with information about their mentally ill relative but also information on how to cope with their situation. Spirituality was found to be central in the family member's ability to cope with their mentally ill relative. The use of spirituality as a coping strategy may suggest a positive influence on the family member's overall coping ability. Overall, family members of inpatient psychiatric patients coped more effectively with emotion-focused coping strategies, which included communicating with family, cognitive distraction , cognitive restructuring (acceptance of problem), and spirituality.Further research utilizing the Neuman Systems Model is needed to investigate how families in the United States cope with mental illness. Specifically, research related to the environmental factors that influence a family member's overall coping ability, such as the length of time coping with a mentally ill relative, need to be investigated. Also, further research is needed regarding how specific demographic factors influence the family's ability to cope with mental illness. Identifying variables that influence the family's coping ability may improve the health and functioning of the family.Using the Neuman Systems Model to help understand the environmental forces that impact the client system will offer nurses insight into the family's coping ability. Nurses must remain sensitive to the stigma associated with mental illness and strive to promote mental health awareness. Advocating mental health services is another role in which nurses are able to affect patient outcomes positively. Also, nursing researchers should continue to investigate the impact that mental illness has on the family. By learning more about how families cope with mental illness, nurses will be able to provide interventions that support healthy family functioning.Further research utilizing the Neuman Systems Model is needed to investigate how families in the United States cope with mental illness. Specifically, research related to the environmental factors that influence a family member's overall coping ability, such as the length of time coping with a mentally ill relative, need to be investigated. Also, further research is needed regarding how specific demographic factors influence the family's ability to cope with mental illness. Identifying variables that influence the family's coping ability may improve the health and functioning of the family.


There have been few prospective observational studies which recruited older newly-diagnosed cancer patients, and of these only some have reported information on the number needed to screen to recruit their study sample, and the number and reasons for refusal and drop-out. This paper reports on strategies to recruit older newly-diagnosed cancer patients prior to treatment into an observational prospective pilot study and to retain them during a six-month period.Medical charts of all patients in the Segal Cancer Centre aged 65 and over were screened and evaluated for inclusion. Several strategies to facilitate recruitment and retention were implemented. Reasons for exclusion, refusal and loss to follow-up were recorded. Descriptive statistics were used to report the reasons for refusal and loss to follow-up. A non-response analysis using chi-square tests and t-tests was conducted to compare respondents to those who refused to participate and to compare those who completed the study to those who were lost to follow-up. A feedback form with open-ended questions was administered following the last interview to obtain patient's opinions on the length of the interviews and conduct of this pilot study.3060 medical charts were screened and 156 eligible patients were identified. Of these 112 patients participated for a response rate of 72%. Reasons for refusal were: feeling too anxious (40%), not interested (25%), no time (12.5%), too sick (5%) or too healthy (5%) or other reasons (5%). Ninety-one patients participated in the six-month follow-up (retention 81.3%), seven patients refused follow-up (6.2%) and fourteen patients died (12.5%) during the course of the study. The median time to conduct the baseline interview was 45 minutes and 57% of baseline interviews were conducted at home. Most patients enjoyed participation and only five felt that the interviews were too long.It was feasible to recruit newly-diagnosed cancer patients prior to treatment although it required considerable time and effort. Once patients were included, the retention rate was high despite the fact that most were undergoing active cancer treatment. Nevertheless, the manifestations and course of cancer in this older population have not been well investigated and remain poorly understood -6. Moreosessment ,12. Fraisessment  have devsessment ,15. Unlisessment ,14,16. Isessment ,17. To oThere have been many studies that have reported that older patients are underrepresented in cancer clinical trials due to a variety of reasons ,18-27. Fat risk of adverse outcomes of cancer treatment, it was crucial to conduct the baseline interview prior to cancer treatment. The window of opportunity for recruitment of older newly-diagnosed cancer patients was thus narrow, making recruitment more challenging. The aim of this study was to examine the feasibility of recruitment older newly-diagnosed cancer patients prior to treatment into an observational prospective pilot study and to retain them during a six-month follow-up period.In the context of an observational prospective pilot-study conducted to describe the health and vulnerability of older newly-diagnosed cancer patients and the adverse outcomes of treatment, we evaluated and report our recruitment and retention strategies to optimize their use for future larger studies. As we were interested whether the concept of frailty is useful to identify older patients The study sample was recruited at the Segal Cancer Centre which is a comprehensive cancer centre. It is a referral center for local and regional patients. It serves the adult population referred by other doctors and other hospitals in Quebec for further investigation and cancer treatment [see Figure prior to cancer treatment and the participants were followed for six months with face-to-face follow-up interviews at three and six months and telephone interviews at 1.5 and 4.5 months [see Additional file The baseline interview took place st 2007 and ended on January 31st 2008 for all cancers except colorectal cancer for which recruitment ended on May 1st 2008.Patients were identified through the lists of appointments at the oncology, pulmonary oncology and haematology oncology clinics. A letter to the physician including the inclusion and exclusion criteria and a patient information letter were added to the chart of each eligible patient . Furthermore, the reasons for refusing to participate by eligible patients, the reasons for drop-out, the number of meetings and time required to complete the interview and reasons for postponement were recorded. The time needed to complete the interview was defined as the time between the start and the end time of the interview. If the interview was completed in two parts the total time was summed. The time needed to complete the interviews was only calculated for those respondents who completed the entire interview, i.e. those who completed To compare the baseline characteristics of those who completed the study, died while on study or refused further follow-up we used the baseline sociodemographic information collected , and born in Canada (yes or no)). Information on diagnosis, stage of disease, treatment plan proposed and whether or not they were enrolled in a clinical trial was obtained from the medical records. The extent of disease at diagnosis was classified as early (stage 0–2) or advanced (stage 3–4). The Eastern Oncology Cooperative Group Performance Scale (ECOG PS)   was usedPatients who completed the follow-up of 6 months were asked to provide feedback by filling out a one-page questionnaire after the last interview. Participants were asked to gauge the strength of their agreement with the statement "I found the length of the interview too long" (strongly disagree to strongly agree) for both the telephone and face-to-face follow-up interview. Furthermore, they were asked three questions: 1) Are there questions that you found irrelevant, unpleasant or too difficult? If yes, could you explain why? 2) Are there topics that we did not discuss in this study, but you find important for your health and functional status ? 3) Other comments or suggestions with regard to the conduct of this study?Descriptive statistics including means and proportions were used to describe the characteristics of those who were newly-diagnosed but excluded because they did not fulfill all inclusion criteria, of the patients who refused and of the patients who participated in the study. A non-response analysis was conducted using chi-square tests and two-sample t-tests. Descriptive statistics were used to describe the mean duration and the reasons for postponement of interviews and the opinion of patients on the length of the interviews. To examine if the feasibility  of the study was different based on the characteristics of the patients, the participants were grouped in several ways. The participants were divided into groups based on median age at baseline (74.1 years), sex, living situation, born in Canada, diagnosis, extent of disease, number of comorbid conditions, IADL disability, and ADL disability. Descriptive techniques such as frequencies and crosstabs were used to compare if the groups based on the characteristics mentioned above differed with regard to the feasibility of the study. The answers to the open-ended feedback questions were transcribed, grouped and counted. Statistical analyses were performed using SPSS version 15.0 .st 2007 until May 1st, 2008, 3060 medical charts of patients aged 65 and over were screened in the Segal Cancer Centre; see Figure From March 1Of the 40 patients (25.6%) who refused to participate, 16 reported that they felt overwhelmed/sad by the diagnosis, were too anxious in relation to the start of their cancer treatment, 5 patients did not feel well enough to participate, 5 patients had no time , 2 patients felt too healthy, 10 persons were not interested, 1 patient refused due to study burden as the patient was also enrolled in a clinical trial and the last person refused due to denial of the cancer diagnosis. However, half of them indicated that they would be willing to participate after the start of treatment (i.e. knowing then what the treatment would be like).The baseline characteristics of those who participated, those who refused to participate and those who were excluded are presented in Table The baseline characteristics of participants who completed the study, died during the study or refused further follow-up interviews are presented in Table Seven participants (6.3%) refused follow-up after the baseline interview. There was an additional patient who refused the third and fourth interview due to a lack of time but participated in the final interview. The reasons for refusal were not longer interested (3), no time (1), too overwhelmed by diagnosis and treatment (2), sick husband (1).Sixty four (57.1%) of all baseline interviews were conducted at home and the remainder were conducted in the hospital, see Table During the study, 2 participants became very ill and proxy interviews were conducted (both participants had lung cancer). For two other participants with cognitive impairment a proxy respondent completed the telephone interview while the face-to-face interviews were conducted with the patient and the proxy together. Only two participants used the transportation offered to come to the hospital for an interview. Nobody used the offer to be compensated for transportation costs to the hospital.In addition, patients were asked their opinion on participating in this study and 84 participants provided feedback  despite the fact that the majority of participants were undergoing active cancer treatment. Most patients did not feel that the interviews were too long. From the feedback received from patients, most had enjoyed participating in the study. In the few prospective studies published with older cancer patients, the attrition rate ranged from 2% to 37%, in part due to study differences in baseline age and disease status, treatment regimes and length of follow-up time (ranging between 6 months to 1 year follow-up) ,41,59-61The planning of interviews with participants undergoing cancer treatment needed to be flexible as a significant number of participants had to postpone and reschedule interview appointments due to a variety of reasons. This is in agreement with the study of Shipman et al  where paTo our knowledge this is one of the first studies with older newly-diagnosed cancer patients examining the recruitment and retention strategies for an observational study that begins prior to cancer treatment. A limitation of our study is that we only recruited participants at one cancer centre and the recruitment and retention process in other hospitals may differ. Due to the small numbers of patients who refused, statistical analyses to compare the characteristics of the refusers to the participants were not possible. Nevertheless, many of the lessons learned in our study  are most likely applicable to other sites when trying to recruit older newly-diagnosed cancer patients. The feedback obtained shows that older newly-diagnosed cancer patients are willing to participate in observational studies while receiving cancer treatment. There is a need to refine the recruitment and retention strategies for conducting observational research with older cancer patients.• Be present in the oncology clinics so that the physician is reminded to verify eligibility of the patient, to ask the patient permission to be contacted by a member of the research team. If the patient agrees to be contacted, the patient can briefly meet with you to know who will be calling or you can explain the study in person in the clinic.• Provide all physicians involved in the patient recruitment with all the materials plasticized in bright colors to post in their exam rooms to remind them of the inclusion and exclusion criteria.• Adjust the recruitment strategies for all the departments involved if necessary and evaluate continuously.• During the informed consent procedure, ask consent to be able to contact a proxy to locate the patient for interviews as older cancer patients are often admitted in several health care institutions during the course of treatment.• Be flexible when planning the interviews and offer home visits and transportation to the interviews.• Organize interviews so that involved family members or friends can be present at the interviews.• Adjust the materials/interviews to older persons with visual and hearing impairment.• Use the same interviewer as much as possible.• Send reminder letters and questionnaires in advance.• Ask the patient consent to inform their treating physician of the results of the interview. Send a summary of the interview to all the physicians within a week of the interview which includes the list of important findings on the different measurement tools used including the established cut-offs, if available.The authors declare that they have no competing interests.MP designed the study, collected the data, performed the data analysis and interpretation and drafted the manuscript. JM participated in the design of the study, interpretation of the results of the data analyses, and helped to draft the manuscript. VG participated in the design of the study, in the data collection, in the interpretation of the results of the data analyses and helped to draft the manuscript. CW participated in the design of the study, data analysis and interpretation of the data, and helped to draft the manuscript. MM assisted in the data collection, was involved in the interpretation of the results of the data analyses and in the preparation of the manuscript. GB was involved in the study design and preparation of the manuscript. HB: was involved in the study design and preparation of the manuscript. All authors have read and approved the final version of the manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2407/9/277/prepubOverview of data collection and questionnaires used at each wave of data collection. Overview of all the data collection cycles and what information was collected during each data collection cycle.Click here for fileDifference in feasibility of interviews by patients' characteristics. Overview of the different aspects of feasibility of the interview by the characteristics of the patient.Click here for file


This paper presents a novel method for the systematic implementation of low-power microelectronic circuits aimed at computing nonlinear cellular and molecular dynamics. The method proposed is based on the Nonlinear Bernoulli Cell Formalism (NBCF), an advanced mathematical framework stemming from the Bernoulli Cell Formalism (BCF) originally exploited for the modular synthesis and analysis of linear, time-invariant, high dynamic range, logarithmic filters. Our approach identifies and exploits the striking similarities existing between the NBCF and coupled nonlinear ordinary differential equations (ODEs) typically appearing in models of naturally encountered biochemical systems. The resulting continuous-time, continuous-value, low-power CytoMimetic electronic circuits succeed in simulating fast and with good accuracy cellular and molecular dynamics. The application of the method is illustrated by synthesising for the first time microelectronic CytoMimetic topologies which simulate successfully: 1) a nonlinear intracellular calcium oscillations model for several Hill coefficient values and 2) a gene-protein regulatory system model. The dynamic behaviours generated by the proposed CytoMimetic circuits are compared and found to be in very good agreement with their biological counterparts. The circuits exploit the exponential law codifying the low-power subthreshold operation regime and have been simulated with realistic parameters from a commercially available CMOS process. They occupy an area of a fraction of a square-millimetre, while consuming between 1 and 12 microwatts of power. Simulations of fabrication-related variability results are also presented. With an average net power consumption of only 1biological processors”, in most cases they require specific conditions and a certain amount of time from start to completion of an operation. For example, one of the most important cellular oscillations in the human body, mitosis, is a highly demanding procedure, which undergoes several stages and requires a large period of time, usually several hours, until it is completed in vitro might lead to significant phenotypic variations and require repetition of the whole process, leading to loss of valuable test time and ultimately to high cost.Although cells are accurate and power-efficient “For these reasons, it can be argued that it is very advantageous to simulate biological and biochemical dynamics by means of powerful computers, which use precise and accurate numerical simulation methods and are able to process huge amounts of data, based on the mathematical equations that describe each cellular or molecular function. Various reduced or extended mathematical models have been proposed, particularly during the last few decades, defining in a more or in a less accurate mathematical way most of the biological rhythms, which take place in the human cell. More specifically, the mathematical description of cellular behaviour has progressed to such a level that a gene-protein regulation network or a cellular/neural network can now be efficiently described by a system of coupled nonlinear differential equations, which incorporate properties, such as stochasticity and cell variability Albeit the mathematical models describing cellular functions have reached an adequate level of accuracy and can be simulated with the use of powerful software, when it comes to the simulation of very large networks of cells, whose dynamics include nonlinearity, stochasticity, cell variability, dynamic uncertainties and perturbation, software simulations start to become extremely demanding in computational power This appearing gap that exists between computer simulations and biology can be filled with the use of certain biomimetic engineering devices, which are capable of generating dynamical behaviours similar to the biological ones observed experimentally. With the use of ultra-fast, ultra-low-power analog chips that are able to simulate single or multiple cell operations and are organised in highly parallel formation, it is possible to implement large VLSI cell networks, which - in principle - could include the time-varying stochastic parameters that define a biochemical system The striking similarities between the equations describing biochemical systems and the equations defining the current-voltage relations between properly interconnected subthreshold MOS devices and capacitors, provide the motivation to emulate a real life cellular behaviour by means of an ultra-low power electrical circuit. The potentials of such an endeavour are tremendous: with the use of the aforementioned circuits, researchers would be able not only to simulate biological responses fast and accurately by simply altering different biological parameters that can be translated into certain electrical parameters, but would also be able to predict a future cell behaviour following a deterministic or a stochastic dynamical description.Inspired by the above, the aim of this paper is to introduce a systematic way of designing such electrical circuits by exploiting the similarities between the Nonlinear Bernoulli Cell Formalism (NBCF) and systems of ordinary differential equations (ODEs) that characterise biochemical processes. The flexibility provided by the NBCF allows us to use simple static translinear blocks for the implementation of mathematical operations, in combination with dynamic translinear blocks whose current-voltage logarithmic behaviour is characterised by the Bernoulli differential equation, to realise in full the differential equations, which specify the considered biological systems.© and Cadence software platforms is presented. Moreover, a section investigating the robustness of the proposed circuits based on Monte Carlo Analysis and Transient Noise Analysis simulations follows. Finally, a discussion section is presented commenting on the similarities of both biological and electrical models and providing an insight into the envisaged applications of such bioinspired devices.The paper is structured as follows: Firstly, we introduce the biological models that characterise the cellular and molecular behaviours. Then present the log-domain mathematical framework used for the transformation of the biological equations into the electrical ones. To illustrate the striking similarities between the original equations and the electrical ones, an in depth mathematical analysis is provided exhibiting the nonlinear properties of both models and examining how close these models are to each other. After the mathematical treatment of both models, a section comparing simulations of these dynamical models produced by MATLABCells in multicellular organisms need to communicate with each other during their daily functions, in order to accomplish a large number of operations, such as cell division, apoptosis or differentiation. The remarkable ways through which this communication is achieved is a result of complicated combinations of electrical or chemical signalling mechanisms. This paper focuses on one of the key intracellular signalling processes, the intracellular calcium  was coined in the international literature by Drakakis in 1997 The current relation of an NMOS device operating in weak-inversion Based on (4), the drain currents of the NMOS and PMOS transistors can be re-expressed as follows, taking into consideration their nonlinear substitution and setting By substituting the current expressions derived from KCL into the aforementioned drain current differential equations, we end up with the following set of differential equations for both transistor types:rent see  so that cascade” topology), where the gate voltage of the first one is logarithmically driven by a constant input current From (12), defining a new dimensionless state-variable ent  see , while tcoupled” BC topology). As will be shown later, it is the coupled interconnection of the dynamic translinear blocks, which “host” the BCs that will allow us to implement the coupled nonlinear biological differential equation systems.For Externally-Linear, Internally-Nonlinear (ELIN) applications hosts” the BC.Starting from the fact that each differential equation of the LDSS can exist independently, a sub-category of the LDSS can hold for cuit see , which “The careful selection of the input and output currents In the previous section of the paper, the term CytoMimetic circuits was introduced. This distinct class of bioinspired circuits aims at simulating cellular and molecular dynamics, based on the mathematical expressions of various, nonlinear, biological models. Our attempts on implementing a wide range of nonlinear models so far, show that the NBCF formalism is a useful tool for transforming biochemical models into their electrical equivalent and as a result design analog circuits, whose outputs will produce dynamics that are very close to the ones of the prototype systems.More specifically, the scope of CytoMimetic circuits is to mimic the time-dependent behaviour of biochemical substances as they are observed experimentally, relying on a time-scaled approach. Thus, there is a distinct difference between them and the other categories of bioinspired circuits, e.g. Neuromorphic The direct correspondence between electrical and biological variables and parameters stemming from the NBCF provides the flexibility required for the realisation of various nonlinear mathematical models by computing their time-dependent dynamical behaviour. The following paragraphs present the method through which we migrate from the biological to the electrical field of equations and will offer a systematic methodology to approach nonlinear biochemical models.The basic structure of the electrical analogous equations is provided by (16) and (17) and is physically implemented by the BC block presented in Now it is time to explain how one can define the input and output currents of the NBCF, which will help us complete the formation of the electrical equations. Being implemented by static TL blocks, the input/output currents However, the selection of the appropriate By separating the terms of the ODE - which are a function of the equation's variables - from the other terms, presenting them onto the LHS of the equations and then setting the system's variables as a common factor, will eventually generate a form similar to (16) or (18). The exemplary, fictitious, two-dimensional system of nonlinear Following this treatment, the terms inside the parenthesis on the LHS may be treated as the Exploiting the freedom provided by NBCF a mathematical equation can be expressed into various equivalent electrical ones; we opt to select the electrical analogous model, which not only implements the desired biological model dynamics but also facilitates compliance with the subthreshold region constraints of MOS operation.CytoMimetic circuits comprise medium complexity dynamic and static TL circuits. Although the majority of the mathematical models that describe cellular or molecular behaviour might require a wide range of different TL blocks combinations, most of them could be derived from or would be a combination of three basic blocks, given that various mathematical operations could be also implemented using different TL network realisations. Regardless of the TL combination chosen to generate the required mathematical operations, the NBCF will hold. In order to demonstrate the systematic nature of the proposed framework in this paper, the following TL blocks have been used for the implementation of all five electrical equivalent circuits presented in this work.hosts” the Bernoulli Cell, it provides an output current The BC block presented in With all devices having the same W/L ratio, the squarer block of Employing devices of the same W/L aspect ratio, the multiplier block allows us to perform multiplication or division operations with currents based on the TL principle:  see . Again, From (1), (2) and (3), five mathematical models can be derived, each one implementing a biological/biochemical function with different properties. In this paper we opt to present in detail the synthesis procedure leading to the electrical equivalent equations and circuits for two prototype models, one from each category. Thus, for the intracellular seconds, they should not be associated to the nonlinear systems' frequency of oscillations. Such quantities now relate to the time scaling of the CytoMimetic electrical equivalents.At this point it must be stressed that regarding the time properties of the implemented electrical analogous circuits, a nonlinear dynamical system approach should be adopted, in order to estimate - roughly - the frequency of oscillation of the considered electrical systems “close” to the critical bifurcation value. Further information on this can be found in The use of the Andronov-Hopf bifurcation theorem is particularly useful to determine CytoMimetic circuits' frequencies of oscillations stem see , provide© software.For the models examined in this paper, the frequency of their oscillations could not be determined by the aforementioned method, since the systems' points of operation are far away from the critical bifurcation point. Consequently, we estimated the frequency of oscillations exclusively through the appropriate use of signal processing tools such as those found in Cadence and MATLABThe model of intracellular The time-varying concentration of cytosolic The time-varying concentration of We have mapped each parameter and variable of the chemical model onto a current in the electrical equivalent one. Although such an approach might seem counterintuitive, especially in the case where the chemical value The correspondence between biological concentration and electrical current is where the Based on the above, we can start forming the electrical equivalent using only the first two terms of (18):ions see  and 4.After the above treatment, substituting (27) into (23) and (24) yields:For the two dimensional case of the genetic regulatory networks model, the following steps have been followed:The time-varying behaviour of protein's We have selected to implement the time-varying behaviour of protein's Each parameter and variable of the chemical model is mapped onto a current in the electrical equivalent one.The correspondence between the units of the prototype and electrical system is gain” current termed In the electrical model, the equivalent of the time scaling factor where the The exact same procedure as before is adopted for the realisation of the electrical equations of this model from the prototype ones presented in (2). Starting once again from the general form of the NBCF in (18) we end up with the following two-dimensional electrical expressions:Based on the above analysis and (34), the relations (30) and (31) are transformed as follows:Exploiting the symbolic representation of the basic TL blocks introduced in section 5, schematic diagrams for the two different biological models are presented in Starting from the general form of the The characteristics of the oscillatory behaviour of both prototype and electrical models are determined by their Jacobian matrixes and eigenvalues. In the following paragraphs, the mathematical properties of the biochemical models and their electrical equivalents are analysed using the aforementioned linearised mathematical tools. The two models studied are the ones of section 6. At this point, it would be useful to add that the remaining models (see section 2) have also been investigated in a similar way and yield similar results.By setting the derivatives of the model in (25) and (26) equal to zero and solving for Setting both derivatives of the electrical equivalent system equal to zero and solving for Following the analytical steps detailed in The fixed points Following the analysis in AMS 0.35  - MM/2P4M c35b4 CMOS technology. MATLAB© and Cadence results have been obtained for certain biological and electrical parameters. The biological parameters' values have been acquired from literature, while the electrical parameters have been calculated from the scaled relation between the two systems. The scaling factors, aspect ratios and capacitance values presented in This section aims at demonstrating the correspondence between the dynamical behaviours generated by simulating both the biochemical/prototype and the electrical models. The software used for the simulation of the aforementioned circuits is Cadence Design Framework (CDF) version 5.1.41, using the process parameters of the commercially available The proposed circuits can operate with different values of the aforementioned quantities and produce similar dynamical behaviours as the ones illustrated in and  see  by a scaThe first case of the intracellular As can be seen from © and Cadence results presented in Both MATLABnces see , and 4 a©. Moreover, simulation results have been performed for various capacitance values to investigate circuit's robustness. The vast majority demonstrated good agreement with MATLAB© simulations for the values presented in The aforementioned simulation results demonstrate good qualitative agreement with each other. The signature of the electrical nonlinear system, i.e. the system's phase plane, shows good agreement with the biological one generated by MATLABCalibrating” this current value served only presentation purposes aimed at highlighting the resemblance between a real, electrical circuits response and the one produced in MATLAB©. As it will be discussed in section 9, minor deviations from the ideal prototype system are a “feature” of this proposed class of circuits. In this case as well, transient and phase plane analysis demonstrates that the two systems are adequately close. However, differences exist at the boundaries of the regions of oscillations for these systems, as illustrated in The second case of the intracellular The third case of the intracellular strikingly similar” simulation results in the set we considered. The non-ideal exponential behaviour of certain devices combined with the strong nonlinearity of the model leads to noticeable deviations from the expected time traces and operating frequency, when the circuit's values are not identical to the corresponding biological ones. Finally, two three-dimensional graphs are shown, in order to demonstrate the behaviour of cytosolic This electrical equivalent circuit is the one with the less “This class of mathematical models presents milder nonlinearities compared to the intracellular concentration/time” in The explicit mathematical analysis of this model takes place in © transient and phase plane results illustrated in The MATLABIn the biological model the parameters Regarding the multiplication of the factor tor  see  by a gaicalibration” is not compulsory for this type of circuits, however, for presentation's sake we have decided to do so, in order to exhibit the potentials of the proposed circuits. Although this type of biological system has been realised via two different, transistor-level approaches, both of them exhibit good agreement with the theoretical transient and phase plane results.Finally, it is important to clarify that although the value of the current The three dimensional case of the gene-protein regulation model is the only three dimensional system included in this paper. The reason that has led to its selection is twofold. The first relates with the fact that the noticeable wide range of its values  analysis. The output signals of the proposed circuits are the drain currents ones see , and 6. Starting with the Log-Domain Intracellular In the sensitive” version of the intracellular The most “The Log-Domain Gene - Protein Regulatory circuits have also been analysed by means of MC analysis. From the 2D case, the circuit implementing the The 3D category of the Log-Domain Gene - Protein Regulatory circuits also exhibits high percentages of successful oscillations in MC analysis. With an expected frequency of 4.9It is important to stress that although the proposed circuits have been tested for their robustness by means of the highly pessimistic MC analysis, the results obtained are adequately satisfactory. For very large VLSI cell networks the variability shown in the MC simulations is a feature that characterises CytoMimetic circuits, which implement the non-identical behaviour of multiple, real cellular responses signal * noise intermodulation takes place. The case of Externally-Linear-Internally-NonLinear (ELIN), time-invariant responses has been studied both theoretically and by means of measurements and simulations The noise behaviour of the presented topologies exhibits the basic characteristic on nonlinear logarithmic circuits operating in accordance with the large-signal exponential characteristic of the individual transistors, i.e. signal-dependent noise floor” behaviour is a saturated SNR ratio for high inputs. Hence, the performance of logarithmic and hyperbolic-sine ELIN responses is characterised by a high dynamic range under constant SNR for strong input signals. Transient Noise Analysis simulations performed on the novel CytoMimetic circuits studied here have confirmed the presence of signal * noise intermodulation. Though noise simulations are not presented due to lack of space, the interested reader can verify that the instantaneous noise tends to increase close to the peaks of strongly non-linear signals  used for the analysis and synthesis of dynamic translinear circuits. We have methodically modified the BCF formalism to yield a systematic electronic realisation method for nonlinear biochemical ODEs. The resulting electronic circuits provide ultra-low-power, fast and accurate means of simulating or predicting cellular or molecular nonlinear dynamics. Simulated results of novel circuit topologies mimicking the nonlinear dynamics of (a) an intracellular calcium oscillations model and of (b) a gene-protein regulatory system model have been used to illustrate the detailed method.CytoMimetic circuits for cellular/molecular dynamics computation have a plethora of possible or envisioned future applications. Firstly, such circuits open up the possibility of efficiently simulating the dynamical responses of large networks of cells or even of accurately mimicking the behaviour of small tissues or organs. Indeed, based on such technology, the molecular dynamics of large numbers of interconnected biological systems can be efficiently simulated in real-time in silico by a microchip with minute power demands and relatively small size. Secondly, when coupled to arrays of biosensors and bioactuators, CytoMimetic circuits can form the basis of fast and relatively cheap, reusable high-throughput drug testing platforms or, alternatively, be employed for the robust and optimal control of biological systems . Both of the aforementioned applications have been investigated by few researchers based on microchips designed using approaches that, contrary to NBCF, do not rely on explicitly defined relationships between the electrical and biological variables. We therefore anticipate that VLSI analog CytoMimetic chips, in principle, have the potential to provide a more efficient and rigorous solution to the applications outlined above.All of the aforementioned represent only a minor part of the potential applications that ultra-low-power biocircuits can have an impact on. It is highly likely that future developments exploiting the methods presented here will shed even more light on the range of applications that such circuits can enable, revealing a promising path for further fruitful research in cybernetic electronics.


The tree stem detection accuracy was 82.6%; the root mean square error (RMSE) of the estimates of tree diameter at breast height (DBH) was 5.06 cm; the RMSE of the estimates of tree location was 0.38 m. The relative RMSE of the DBH estimates was 14.63%. The results showed, for the first time, the potential of the PLS system in mapping large forest plots. Further research on mapping accuracy in various forest conditions, data correction methods and multi-sensoral positioning techniques is needed. The utilization of this system in different applications, such as harvester operations, should also be explored. In addition to collecting tree-level and plot-level data for forest inventory, other possible applications of PLS for forest ecosystem services include mapping of canopy gaps, measuring leaf area index of large areas, documenting and visualizing forest routes feasible for recreation, hiking and berry and mushroom picking.A professional-quality, personal laser scanning (PLS) system for collecting tree attributes was demonstrated in this paper. The applied system, which is wearable by human operators, consists of a multi-constellation navigation system and an ultra-high-speed phase-shift laser scanner mounted on a rigid baseplate and consisting of a single sensor block. A multipass-corridor-mapping method was developed to process PLS data and a 2,000 m Several types of laser scanning systems currently exist, such as: airborne laser scanning (ALS), terrestrial laser scanning (TLS) and mobile laser scanning (MLS). Many laser scanning systems are multi-sensoral platforms, and therefore the technical development of sensors and advances in computing technology allow new development possibilities.Forest resource management is one of the main driving forces in the adoption of laser scanning. The first commercial ALS prototype dedicated to topographic mapping was introduced in 1993. Shortly afterwards, ALS was utilized in forest investigations . The rapReference data for forest inventories are conventionally collected by utilizing expensive and labor-intensive manual measurements ,7. Both Important tree attributes needed in forest mapping and ecosystem services include the diameter at breast height (DBH), location, tree height, tree species, leaf area index (LAI), the height of the first living branch, stem curve, stem volume and biomass. Many attributes, such as the stem curve, are not practically measurable using simple tools. Allometric models can be used to determine attributes that are not directly measurable but can be derived from other basic measurements. The applicability of allometric functions, however, is limited to particular climatic, geographic and silvicultural conditions. The use of inappropriate allometric models can lead to large estimate errors, as was shown previously . In geneRecently, TLS has been proven to be a promising technique in forest field measurements. The first commercial TLS system was built by Cyra Technologies (acquired by Leica in 2001) in 1998, and the first papers related to plot-level tree attribute estimation were reported in early 2000s . CurrentNew TLS systems are continuously being developed, with the size and weight of the laser scanners decreasing rapidly. Dual-wavelength TLS is currently being studied within forest ecology . The useThree measurement approaches have been reported in TLS field measurements: single-scan, multi-scan and multi-single-scan. In the single-scan approach, the laser scanner is placed at the center of the plot and one full field-of-view  scan is made. This approach has the simplest measurement setting and fastest measurement speed in the three approaches because only one scan is applied to a plot. The major problem of this approach, however, is the low detection rate. In the sample plot, 10%–32% of all trees are not scanned from the plot center because of occlusion effects ,18,20,25Several scanning positions are necessary to measure all trees in a plot. In the multi-scan approach, several scans are made inside and outside of the plot. Individual data sets are merged, typically using artificial targets, to form a single point cloud. This approach provides the best data set as the merged point cloud records trees from different directions; however, the approach is not always practical due to the cost of the manual or semi-automated processing required for the registration of several scans. In the multi-single-scan approach, several point clouds are processed individually and data sets are merged at the feature and decision levels. In this approach, the work load is clearly lower than with the multi-scan approach because reference targets are not required and the merging of several scans is fully automated. The detection rate is also clearly higher than that of the single-scan approach because the plot is scanned from several stations.In practice, convenient measurement methods and rapid data acquisition are always preferred. New possibilities are currently being studied to improve the efficiency of field data collection. Laser scanning has recently been put on moving platforms to build MLS systems and is being studied for forest mapping applications. The main advantage of applying MLS for forest measurements lies in its rapid data collection. Within an equal time frame, the area that can be investigated by utilizing MLS is significantly larger than the area investigated with TLS.The MLS system consists of one or several laser scanner(s) and multi-sensor positioning and orientation sensors. The first commercial MLS system for surveying applications was StreetMapper, which appeared in the market in 2006. Similar sensor configurations are also used in robotics. MLS systems utilized in surveying and robotics have different emphases and perspectives. Surveying MLS emphasizes an absolute coordinate system and high measurement accuracy. In robotics, relative positions and accuracy are important. Because of the different applications, real-time processing is necessary for robotics but is only an advantage for surveying MLS.The concept of applying MLS for forest measurement started in early 2010  with theThe data collected by MLS systems is less precise in comparison with TLS because positioning errors propagate in the MLS point cloud. Another challenge of applying MLS is that the mobility of the platform in forest environments may be limited. Forest ground is characterized by rugged terrain and obstacles, such as rocks, dead wood and undergrowth. The ground condition may be not easy or even suitable for vehicle movement. In a pilot study, the applied platform was an all-terrain vehicle (ATV) .Personal laser scanning (PLS) is an emerging concept . The ideThe main advantage of PLS lies in its high mobility in various terrain conditions and rapid data collection. Through professional-quality scanning and navigation systems, the collected data can document objects in detail with high precision. PLS has the potential to improve mapping efficiency compared with conventional field measurements and compensate for the limitations of other laser scanning techniques, such as having to transport the scanner and associated equipment from site to site, which is one major disadvantage of TLS, and having to have certain terrain conditions, which limits the application of MLS. In addition, the PLS measurement scenarios enhance the system capability to record all the trees in the plot because the scanning position and geometry changes all the time. These characteristics are very attractive for forest mapping and ecosystem services.The objective of this paper is to conduct the first experiment that explores the possibility of applying PLS in forested areas, to demonstrate the first professional-quality PLS for collecting tree attributes for forest mapping and to discuss the implications of utilizing such a system for ecosystem services in a wider context.2.2.1.This study was conducted utilizing the wearable PLS system developed and built at the FGI. The name of the system is AKHKA R2. The system consists of a multi-constellation navigation system, which includes a Global Navigation Satellite System (GNSS) receiver (NovAtel Flexpak6), an inertial measurement unit (IMU) system (NovAtel UIMU-LCI) and an ultra-high-speed phase-shift laser scanner (FARO Focus3D 120). The receiver tracks NAVSTAR's Global Positioning System  satellites and Global Navigation Satellite System (GLONASS) satellites. In the PLS, the sensors are mounted on a rigid platform. The scanner is installed upwards on the platform with a helical mount kit, the IMU is installed right below the scanner and the GNSS antenna is mounted upwards next to the scanner. The scanner, IMU and GNSS antenna form a single sensor block. The sensor block can also be turned upside down for certain applications, such as ground mapping. The configuration minimizes the need for system calibration because the offsets and rotations between the scanner and IMU remain the same all the time. In operation, the system is on the operator's back and is tilted forward slightly, typically at approximately 20°, and the scanning plane is cross-track. The tilted scanning allows detection of vertical break-lines of stems. If the system was precisely vertically configured, the accuracy of the system for the vertical break-line detection of stems is determined by the scan frequency and walking speed. With the tilted configuration, a higher sampling frequency for break-line features can be achieved because angular resolution within a scan line is significantly higher in comparison with the resolution between scan lines. During the field measurement, swinging up to several degrees can be expected because of the operator's body movement and the system not being tightly fixed on the operator's back.i.e., sensor offsets and rotations).The GNSS receiver records the platform positions at 1 Hz and the IMU records the platform accelerations at 200 Hz. These data are typically combined in post-processing with reference GNSS data from either a virtual reference data service or physical station on a bench mark to produce the mapping path. The navigation system also records the time signals sent by the scanner. This time signal is utilized to match laser points to scanner position and orientation along the mapping path. 3-D georeferenced points are calculated utilizing the individual scanner positions, the synchronized scanning data and the system calibration data (2.2.2 (40 m × 50 m) rectangular forest plot was utilized in this study. The dominant tree species in the test area is Scots pine (Pinus sylvestris L.). Other species growing in the plot include Norway spruce (Picea abies L.), birch (Betula sp. L.) and aspen (Populus tremula L.). The DBH ranges from 10 cm to 51 cm, and the standard deviation (std. dev.) is 11.48 cm. The tree density is 0.023 stems/m2 (DBH over 10 cm). Descriptive statistics of the test plot at the time of the field inventory are summarized in The test was carried out in a mature forest plot in an area behind FGI in Masala , southern Finland. A 2,000 mThe forest stand structure is built by two layers: an upper story of sparse, large crowns, and a last story of denser shrubs and young coniferous and deciduous trees. The ground is mostly covered by moss and shrubs, and bare bedrock areas and boulders are common. The ground slope of the study area is approximately 9° from north to south. No permanent walking path is present in the test plot.2.3.PLS data were acquired in May 2013. The point repetition frequency was 488 kHz, and the scanning frequency was 97 Hz. Virtual reference station (VRS) data and positioning measurements were used in post-processing to compute the mapping path.Noise is commonly present in PLS-generated laser point clouds when a phase-based distance measuring system is utilized. Noise points are a result of either weak returns or multiple hits within the laser beam (which yields to a phase slip in the ranging procedure). The scanner employed by PLS provides some on-the-fly filters to diminish noise, such as contour and clear sky filters. This function was turned on in the experiment.The PLS field measurement is shown in The reference data were collected in August 2013. Tree locations were measured from a fixed location inside the plot using a Trimble 5602 DR 200+ total station. The total station was oriented to the same coordinate system as PLS data using VRS-GNSS measurements. The observation location was selected so that trees in the plot are visible. The stem perimeter of each tree was measured by a steel tape to the nearest millimeter at DBH height . The DBH was later calculated from the stem perimeter (assuming the tree cross-section is circular) with millimeter accuracy. The tree species were also recorded in the field measurements.3.3.1.x meters from the scanner and had an intensity value less than y.The raw point data were filtered for noise removal in two phases. The first step deleted noise by intensity and range thresholds and was performed simultaneously with the georeferencing of the point data. Points were excluded if they were beyond a range of x was set to 50 in this experiment. The intensity range of the scanner was 0–2,047. Points with a low intensity value typically have no reasonable accuracy. In this experiment, y was set to 700. The threshold of intensity value was experimentally determined.In forested areas, visibility is typically poor for stems standing far away from the scanner because of occlusion effects . Taking The second phase was the removal of isolated points. Points were labeled as noise if there were no other points within a 10-cm radius. These points were most likely not reflected from real objects in the surrounding environment. In addition, 100 points were required to be within a 1-m radius to detect small, yet isolated point clusters, which are typically present in phase-shift ranging data. The reduction rates in this phase were approximately 10% of input data.3.2.In general, there are two possible scenarios for PLS data processing. The first one is based on co-registration of along-track and across-track data strips by having joint surface patches between the data strips. This approach is similar to the strip adjustment approach applied in ALS ,33 and td meters from the path. In this study, d is equal to 20. Tree stems within this corridor were detected and then modeled from the laser point data. Each laser point was automatically processed in its neighborhood to identify possible stem points. The size of the neighboring space was determined by the local point density in the neighborhood. The higher the local point density, the more details are recorded in the point cloud; therefore, a smaller size of neighboring space is required to understand the characteristics of objects and preserve the details. When the local point density is low, the features are usually poorly described and a larger neighboring space is necessary to acquire enough neighboring points for the stem detection. The neighboring space is defined by k-nearest points, so that the size of the neighboring spaces can be self-adjusted according to the local point density. The k value was 100 in this study based on the overall point density evaluation in the whole dataset.A corridor was established beside the mapping path, which included points within A local coordinate system was established in this space, where eigenvectors indicated the axis directions and eigenvalues indicated the variances of the points along the axes. The planar surface was identified if neighboring points were mainly distributed along two axes in the local coordinate system. The vertical shape was recognized by the normal vector to the surface, which was approximately horizontal in the real world coordinate system. Tree stem models were built from the recognized stem points. A series of 3-D cylinders were utilized to represent stem shapes, such as changing growth directions. To match a cylinder to a stem section, laser points were weighed to reduce the influence of noise, such as branch points. For additional details on the modeling procedure, reader is referred to . The DBHDepending on the path and the size of the buffer, overlaps may exist between corridors. Therefore, a tree may be mapped several times in the preliminary mapping. These results were then analyzed and merged at a decision level.The merging criteria were the stem location and detected stem points. Several tree stems with the same location were identified as the same tree recorded in different mapping paths. For each detected stem, the laser points were located and the stem with the largest number of points was selected as the final detection. The decision criterion assumes that the more laser points reflected from the stem, the more reliable of a stem model could be made. More discussion on this decision criterion is provided in Section 5. The merged results produced the final plot map.For comparison, all laser points within the plot were merged as one data set by using navigation signals. This new data corresponds to the multi-scan data in the conventional TLS measurement and was processed utilizing the same detection and modeling procedures as in the individual corridors.3.3.The mapping results were evaluated utilizing measured references. The mapping accuracy was evaluated on the basis of omission errors, commission errors and overall accuracy. Omission errors are references that were not mapped. Commission errors are objects that were mapped but did not have corresponding references. Overall accuracy is the percentage of correct detections.iy is the ith estimate, riy is the ith reference, rȳ is the mean of the reference values, and n is the number of estimates. The multipass-corridor-mapping method was also evaluated by comparing its mapping results with results obtained from the merged point cloud.The accuracy of the DBH and position estimates were evaluated utilizing the bias and root mean squared error (RMSE), and the relative bias and RMSE, as defined in 4.4.1.The results of the stem mapping utilizing the multipass-corridor-mapping method and the PLS system are reported in The omission errors were eight reference trees that were not mapped, which included two trees not covered in point cloud data because of shadowing effects, one young spruce tree whose stem was heavily occluded by its branches, and five cases where the stems were barely recorded in the data set.The commission errors included eleven detected trees without corresponding reference data. One tree was just on the plot border, which was not in the reference because of its location. Ten commissions were tree groups or small trees with a PLS estimated DBH between 10 and 17 cm. The studied forest plot has many saplings, and the references have a DBH greater than 10 cm. In the field measurement, small saplings with a DBH just above 10 cm may not have been recorded because the field crew estimated that they did not equal or exceed the minimum diameter criteria. For the PLS stem modeling, small stems with a DBH just under the minimum criteria may be modeled as a bit larger, so that they were estimated as those fulfilling the diameter criteria. This type of commission error is typical in forest areas where there are many small saplings. The accuracies of the DBH and the position estimates are reported in 4.2.In this case, the omission errors were twelve reference trees that were not mapped, which included two trees not covered in point cloud data because of shadowing effects, one young spruce tree whose stems were heavily occluded by its branches, three trees where the stems were barely recorded in the data set, and six other trees that were not modeled mostly because of mismatching effects.The commission errors were ten detected trees without corresponding reference data. Two trees are on the plot border, and eight commissions were small trees or tree groups.The accuracy of the DBH and the tree stem position estimates utilizing merged point cloud are reported in 5.One of the major advantages of applying PLS is rapid data acquisition of the entire forest plot. In this test, it took less than 2 min to map the test plot. The current PLS system is capable of recording approximately 1 million points per second and weighs approximately 10 kg. In the coming years, it is expected that the scanning frequency will be higher and the weight of the PLS systems could be reduced, e.g., to a few kilograms. In principle, the PLS system is easy to put on and operate, and the whole plot can be recorded in a minute or in a few minutes.The PLS has some clear advantages over TLS when taking field measurements. PLS solves the TLS-related problems of setting up the system and using calibration targets on tripods. In addition, transferring the scanner between scanning positions and from one plot to the next can be faster using the PLS system because all equipment is on the operator's back. Transferring from one plot to the next can be also accomplished using ATVs, which expedites field measurements and makes PLS easy to operate in the field.In addition, the PLS point cloud is less sensitive to distance than the TLS data. The PLS provides a multi-view mapping scenario that records an object from different directions as the operator position and viewing geometry are constantly changing and records the entire plot by walking through it. A more equally distributed point cloud can be obtained by utilizing PLS. Access to all trees and collecting a point cloud representing all trees can be more easily guaranteed using PLS because the operator can identify areas that deserve additional attention and scan those locations. The errors related to missing trees with the TLS approach can be minimized by using PLS.Previous research showed that the single-scan approach misses up to 32% of all trees in the sample plot because of occlusion effects ,18,20,25This result also indicates that it is important to plan the walking path before the measurement to minimize missed trees. In this experimental data set, the south-east corner was hardly covered because of occlusion effects, which were not expected before the experiment. This result shows that the field crew plays an important role in utilizing PLS system because he/she needs to plan the mapping path carefully or identify areas that deserve additional visits.In this study, a multipass-corridor-mapping method was developed for processing PLS data in a forested area. The method first processes data along the mapping path independently and then merges the detecting results at a decision level. The merging criterion is the number of stem points in each walking path.The mapping of forest sample plots at the decision level was first proposed in . In thatIt is worth noting that there are differences between DBH measurement methods . For exaThe DBH estimate of the multi-single-scan approach is more accurate than the results obtained using multipass-corridor-mapping. The multipass-corridor-mapping method estimates stem attributes in one path where the visibility of a tree stem is supposed to be the best. This mechanism is very close to the multi-single-scan approach. Therefore, different estimate results most likely came from the test data.Different forest contexts, such as different species, varying amounts of ground vegetation and different developmental classes, influence the estimate accuracy of tree attributes. For example, the experiment plot in this study has a low stem density but contains many young trees in undergrowth that make the DBH estimate challenging. However, the main influence is expected to be the different characteristics of the laser point clouds collected by static TLS and PLS.In the PLS, the point cloud was collected using a mobile system that included a scanner and a navigation unit wore by an operator. The point cloud collected by PLS was less accurate in comparison with the static TLS because navigation errors lead to inaccurate position estimates and these errors propagated in the laser point cloud.Satellite signals under forest canopy can be weak and easily interrupted. The lack of proper satellite visibility leads to less accurate platform positions and also undermines the heading angle estimates. For example, a 0.05° heading error yields a 2 cm location measurement error at 25 m distances from the scanner. These errors are reflected finally in the georeferenced point cloud because the laser point cloud is calculated with the GNSS information. Consequently, the accuracy of PLS laser points is lower than static TLS measurements.The RMSE of the DBH estimate was 5.06 cm in this study when utilizing the multipass-corridor-mapping approach and PLS data and it was 0.74–2.41 cm when utilizing the multi-single-scan approach and TLS data. The less accurate results from PLS data showed the positioning errors propagate to the point cloud data.The multipass-corridor-mapping approach estimates the DBH of a tree stem in the path where the visibility of the tree is the best, so the point cloud includes single-path positioning errors. When utilizing the merged PLS point cloud, the RMSE of the DBH estimate was 8.45 cm, which is less accurate than the estimate utilizing the multipass-corridor-mapping approach. This result indicates merged PLS data include positioning errors caused by combining data from several paths, which makes it less accurate. As shown in the In general, the PLS provides a new measurement principle to document trees and other characteristics of forest plots. The results from the first experiment show that the PLS has a clear potential to be developed into an effective, convenient and practical tool for forest inventory and management purposes.In addition to collecting tree and plot level data for forest inventories, the system can be used to objectively analyze the extent of canopy gaps, measure LAI from large areas and document and visualize forest routes feasible for recreation, hiking and berry and mushroom picking. The transmissivity of forest canopies can also be studied from the ground with the use of the PLS. In the application of ALS-based forest measurement, the transmissivity should be understood before studying terrain information under canopy covers. Currently, there is a lack of detailed information regarding the maximum effective measurement angle where the laser pulse still transmits through the canopy and back.Harvester operations can also be improved by utilizing the PLS systems. Visiting forest areas before harvesting could provide preliminary information that is useful in the bucking process during harvesting. For example, a local stem curve allometric model created from point cloud data could optimize the bucking process and selection of trees to be cut. Because the system does not require professional knowledge of forests or laser scanners, this information can also be provided by the land owner prior to timber trading.There are still several areas where improvements are needed. The technological disadvantages of the PLS need to be further studied. One clear challenge is the problem with positioning and orientation in dense forests. The results in this study showed that the estimated accuracy of tree features, such as DBH, is directly dependent on positional accuracies, as shown by the different accuracies of DBH estimates between using multipass-corridor-mapping and multi-single-scan approaches.The accuracy of PLS  is similar to that of ALS, which is based on the accuracy of the GNSS and IMU. When the visibility of GNSS satellites is poor, the quality of the applied IMU determines the system's capability to manage such challenging situations and determines the overall positioning performance. High relative accuracy is needed to attain a point cloud of trees with less than 1–2 cm deviations. In dense forest, positioning accuracy resulting from the use of GNSS and IMU is inadequate. Data correction methods should be developed to improve positioning reliability in PLS. In addition, multi-sensoral positioning techniques should be investigated.In addition to the navigation components, other features in forested areas can also introduce positioning errors, such as the terrain and abrupt movements of the PLS system, which directly affect the point distribution on the object surfaces. The test area in this study is on a hill slope with understory and bare rocks. The operator may make more sudden movements in this type of terrain in comparison with flat terrain. The influence of terrain or movements needs further investigation. Additional discussion is also needed about methodologically minimizing such influences that are introduced by environmental features.The results in this study showed that PLS data have clearly different characteristics in comparison with conventional, static TLS data. The positioning errors due to the position system produce clear variations in the PLS data. Therefore, it is expected that TLS processing methods cannot necessarily be directly applied to PLS data. Further research is needed to develop new processing methods for PLS point clouds.In forest mapping, the use of PLS is not limited to circular or rectangular plots that are currently in wide use. The visible area beside a single strip may serve as a forest plot in the future. For example, a 20–50 m long and 6–20 m wide strip may be used as a plot, especially when ALS data are also utilized. Areas corresponding to visible trees will then to be utilized as the effective plot area. This possibility needs to be further explored and verified for feasibility and validity.6.Advancements in sensor technology, system development and data analysis formulate the concept of the professional-quality personal laser scanning (PLS) system. This paper details the first experimental results from a PLS field test and demonstrated the applicability of such a system in a forested area for collecting tree attributes. The new PLS system has great potential for utilization in various forest ecosystem services as well as in other areas, such as cities and built environments. The multipass-corridor-mapping provides an effective method of processing data collected utilizing a PLS system.Because of positioning errors, quality of PLS data can be expected to be lower in comparison with static data acquisition instruments such as terrestrial laser scanning, especially in forests with dense tree crowns that blocks GNSS signals. Currently, the RMSE of PLS DBH estimate is about 5 cm. This error is large and may introduce substantial bias when the PLS DBH estimates are utilized in estimating other tree features such as volume and biomass. High quality data are one of the key factors of applying PLS in forest mapping and ecosystem services. Further development is needed for data correction methods and multi-sensoral positioning. Additionally, further research is needed to explore the mapping accuracy in different types of forests and the influences of environmental factors, such as forests with rough and/or steep terrain and with a lot of branches and/or understory. The possibilities of applying the new plot concept (visible area besides a single strip) should also be further discussed.In general, PLS is expected to be a very practical and convenient instrument to make the tree inventory and to document other tree characteristics in forested areas where the quality of PLS data matches the requirement of the application. The technological disadvantages and the new application possibilities of PLS need to be further studied.