Sudha R. Raman

One-Step In Situ Biosynthesis of Graphene Oxide–Bacterial Cellulose Nanocomposite Hydrogels

Graphene oxide-bacterial cellulose (GO/BC) nanocomposite hydrogels with well-dispersed GO in the network of BC are successfully developed using a facile one-step in situ biosynthesis by adding GO suspension into the culture medium of BC. During the biosynthesis process, the crystallinity index of BC decreases and GO is partially reduced. The experimental results indicate that GO nanosheets are uniformly dispersed and well-bound to the BC matrix and that the 3D porous structure of BC is sustained. This is responsible for efficient load transfer between the GO reinforcement and BC matrix. Compared with the pure BC, the tensile strength and Youngs modulus of the GO/BC nanocomposite hydrogel containing 0.48 wt% GO are significantly improved by about 38 and 120%, respectively. The GO/BC nanocomposite hydrogels are promising as a new material for tissue engineering scaffolds.

Prevalence and risk factors associated with low back pain among health care providers in a Kuwait hospital.

Study Design. A cross-sectional survey among health professionals working in a Kuwait hospital. Objective. To investigate the prevalence and factors associated with low back pain (LBP). Summary of Background Data. The literature suggests that health professionals are exposed to occupational risk factors that predispose them to developing LBP. These rates are not well established in Middle Eastern countries such as Kuwait. Methods. A self-administered survey was conducted with health professionals in an urban orthopedic hospital. Results. The response rate to the survey was 60% (n = 344). Lifetime prevalence of LBP in the sample was 70.9%, and point prevalence of LBP was 21.5%. Factors associated with acute LBP included direct patient contact (P = 0.015), performing patient lifts and/or transfers (P = 0.016), low job satisfaction (P = 0.039), and poor self-reported health status (P = 0.019). The prevalence ratio (PR) of reporting acute LBP was also found to increase as a function of the number of daily lifts/transfers performed (PR: 1.4; 95% CI: 1.27 to 1.70). Other factors generally associated with LBP, such as age, sex, professional experience, smoking and exercise, were not found to be significantly associated with LBP in this study. Conclusion. No causal relationships can be inferred using these cross-sectional data. However, results suggest that direct patient contact that includes lifting and/or transferring patients may be an important risk factor. Further research is warranted to evaluate effectiveness of back education and prevention programs among hospital staff in Kuwait.

A novel three-dimensional graphene/bacterial cellulose nanocomposite prepared by in situ biosynthesis

Graphene has been widely used to reinforce various hydrogels while there is no report on the composite hydrogels of bacterial cellulose (BC) and graphene. In this work, a graphene/BC (GE/BC) nanocomposite hydrogel was prepared by in situ biosynthesis. The morphology and structure of the obtained GE/BC nanocomposite were characterized by SEM, TEM, XRD, and Raman. Results showed that the presence of graphene in the culture medium of BC changed the crystalline structure of BC while the in situ biosynthesis process had no influence on the structure of graphene. It was found that graphene nanoplates were uniformly dispersed in the three-dimensional (3D) BC matrix and tightly bound by BC nanofibers. This unique 3D structure will impart the GE/BC nanocomposite with excellent mechanical, electrical, and biological properties.

Stimulant treatment and injury among children with attention deficit hyperactivity disorder: an application of the self-controlled case series study design

Objective The aim of the present work was to assess the short-term effects of stimulant medication use on risk of injury among children diagnosed as having attention deficit hyperactivity disorder (ADHD). Methods The study group for this self-controlled case series study was children aged 1–18 years old diagnosed as having ADHD who experienced an incident medically-attended injury event and received at least one prescription for stimulant medication between 1993 and 2008 (n=328), identified from The Health Improvement Network primary care database from the UK. Conditional Poisson regression was used to estimate incident rate ratios (IRR) and 95% CIs for injury comparing periods of time exposed to stimulant medication to unexposed periods. Results Among children with ADHD prescribed stimulant medication, the rate of medically-attended injury was decreased during periods of stimulant medication use as compared to unexposed periods (IRR 0.68, 95% CI 0.50 to 0.91). There was evidence of a protective association among males and among children aged 10–14 years. This effect did not change over time on treatment. Conclusions Stimulant medication use may decrease the risk of injury among children treated for ADHD, although unmeasured time varying confounding may be an alternative explanation. Injury risk may be considered during the decision-making process with regard to medication continuation among children with ADHD.

Preparation of three-dimensional braided carbon fiber-reinforced PEEK composites for potential load-bearing bone fixations. Part I. Mechanical properties and cytocompatibility

In this study, we focused on fabrication and characterization of three-dimensional carbon fiber-reinforced polyetheretherketone (C3-D/PEEK) composites for orthopedic applications. We found that pre-heating of 3-D fabrics before hot-pressing could eliminate pores in the composites prepared by 3-D co-braiding and hot-pressing techniques. The manufacturing process and the processing variables were studied and optimum parameters were obtained. Moreover, the carbon fibers were surface treated by the anodic oxidization and its effect on mechanical properties of the composites was determined. Preliminary cell studies with mouse osteoblast cells were also performed to examine the cytocompatibility of the composites. Feasibility of the C3-D/PEEK composites as load-bearing bone fixation materials was evaluated. Results suggest that the C3-D/PEEK composites show good promising as load-bearing bone fixations.

Creation of macropores in three-dimensional bacterial cellulose scaffold for potential cancer cell culture

There is an increasing need for an effective in vitro model that can resemble the 3-D nature of tumor microenvironments. In this work, a 3-D bacterial cellulose (BC) scaffold with macropores was fabricated by a facile freeze drying method for potential culture of cancer cells. This in vitro study reported, for the first time, the role of macropores in the adjustment of cancer cell behavior when compared with previous results cultured in BC scaffolds without macropores. The scaffold was characterized by SEM and mercury intrusion porosimeter. A human breast cancer cell line (MDA-MB-231) cultured in the macroporous BC scaffold was examined via cell proliferation, histological and SEM analyses. The results demonstrated that the macroporous scaffold provided a good environment for cell viability, adhesion, proliferation, and infiltration. These findings suggested that the macroporous BC scaffold might have great potential for use in the in vitro culture of cancer cells.

Emotional health of Canadian and Finnish students with disabilities or chronic conditions

The purpose of this study was to investigate the dimensions of emotional health in two population-based groups (Finland and Canada) of adolescents (ages 13 and 15 years) who self-identify as having a disability or chronic condition, as conceptualized by the WHO International Classification of Functioning, Disability and Health. Data from the 2002 WHO Health Behaviour in School-aged Children survey were used to compare the prevalence of emotional health (items on feeling low, feeling nervous) within and between countries. Eighteen percent of the Canadian and Finnish samples indicated they had a long-time disability, illness or medical condition. Canadian adolescents with disability or chronic conditions felt low significantly more frequently than their classmates without disability or chronic conditions. In both countries, students with disabilities who had more than one functional difficulty were significantly more likely to report feeling low and nervous. These results illustrate that the severity of disability as measured by the number of functional difficulties, and not merely the presence of disability or chronic condition, or particular functional difficulties, may play an important role in the emotional health of adolescents. Health promotion programs may use this information to guide practice to support the emotional health of students with disabilities.

Associations between Adolescent Risk Behaviors and Injury: The Modifying Role of Disability.

BACKGROUND Adolescents with disabilities are at risk for poor health outcomes including injury. The objective of this study was to examine if disability status modifies the association between risk behavior and injury among adolescents. METHODS The cross-sectional Health Behavior in School-Aged Children Survey was administered to a representative sample of 7235 Canadian students (grades 6-10) in 2002. Students who reported at least 1 functional difficulty due to a health condition were classified as having a disability. Engagement in up to 6 individual risk behaviors and a summative multiple risk behavior score were considered the primary exposures. Primary outcomes included medically attended injury experienced during a 12-month period. RESULTS Sixteen percent of students reported a disability. Almost all risk behaviors and all injury outcomes were more common among students with disabilities than in those without disabilities (eg, older age groups smoking: 17.5% vs 8.9%, p = <.01; medically attended injury: 67.4% vs 51.4%, p = <.01). Clear risk gradients were observed between engagement in multiple risk behavior and all injury outcomes. The association between multiple risk behavior and injury was accentuated by disability status among older students, particularly for students with disabilities who engaged in frequent multiple risk behavior (adjusted risk ratio 1.8, 95% CI: 1.6-1.9). CONCLUSIONS Canadian students with disabilities who engage in risk behaviors experience higher risks for medically attended injury than their nondisabled peers who engage in those same risk behaviors. Injury prevention programs that focus on risk-taking behavior should integrate the needs of this high-risk group of adolescents in order to prevent additional disability.

An Observational Study of Pharmacological Treatment in Primary Care of Children With ADHD in the United Kingdom

OBJECTIVE The study described initial pharmacological treatment of children in the United Kingdom diagnosed as having ADHD and assessed predictors of medication persistence. METHODS U.K. children ages 3-16 diagnosed as having ADHD between 1994 and 2006 were identified from primary care practice data. Child characteristics, prescription patterns, and initial medication prescribed were described over the study period. The associations of child and clinical factors with medication persistence (defined as initial treatment length greater than six months) were estimated by using binomial regression. RESULTS Of 2,878 children with an ADHD diagnosis, 46% (N=1,314) received at least one prescription for ADHD medication within two years of diagnosis. The mean initial treatment length was 10.7±.5 months. Only 35% (N=464) of pharmacologically treated children had a treatment length greater than six months after initial medication prescription when the analysis used a 30-day grace period; 57% were persistent in treatment when a less stringent 60-day grace period was used. Children who were initially prescribed long-acting methylphenidate were more likely to persist in treatment than those prescribed standard methylphenidate (risk ratio=1.2, 95% confidence interval=1.1-1.4). CONCLUSIONS A large proportion of children who received medication for ADHD in primary care did not continue in initial treatment for more than six months. Few child or clinical factors were associated with treatment persistence. Epidemiological research about the effects of long-term ADHD medication use should account for the observed limited persistence in medication treatment.

Injury among 1107 Canadian students with self-identified disabilities.

Purpose. Students with disabilities are at risk for poor health outcomes; however, the causes and consequences of injury in this group are not well understood. The epidemiologies of injuries among students with and without disabilities were profiled and compared. Methods. The cross-sectional, 2002 Health Behaviour in School-aged Children Survey, was administered to a representative sample of 7235 students (grades 6 – 10) from Canada. Students who reported at least one functional difficulty due to a health condition were classified as having a disability. Primary outcomes were: (i) Medically attended injury; (ii) multiple injuries, and (iii) serious injury experiences during a 12-month period. Results. Some 16.3% of students reported a disability. Injuries were more common in students with disabilities compared to those without disabilities (67% vs. 51% annually, p < 0.01). Students with disabilities experienced 30% increases in the risk for medically attended injury, multiple injury, and serious injury as compared to their peers. Consistent and statistically significant associations (p < 0.05) were identified between different types of disability and all injury outcomes. Conclusions. Canadian students who report disabilities experience higher risks for injury than their peers, perhaps due to an inability to perceive and avoid environmental hazards. Injury prevention programmes are needed to address these unique risk profiles in order to prevent additional disability or secondary conditions.