Transition from a simple yield-stress fluid to a thixotropic material.

From magnetic resonance imaging rheometry we show that a pure emulsion can be turned from a simple yield stress fluid to a thixotropic material by adding a small fraction of colloidal particles. The two fluids have the same behavior in the liquid regime but the loaded emulsion exhibits a critical shear rate below which no steady flows can be observed. For a stress below the yield stress, the pure emulsion abruptly stops flowing, whereas the viscosity of the loaded emulsion continuously increases in time, which leads to an apparent flow stoppage. This phenomenon can be very well represented by a model assuming a progressive increase of the number of droplet links via colloidal particles.

Abuse during pregnancy in Mexico City.

OBJECTIVE: Measure the prevalence of physical and sexual abuse during pregnancy, determine the nature and severity of abuse, and assess correlates with abuse. METHOD: A total of 1314 women seeking prenatal care between July 2000 and January 2003 were approached at three public hospitals in Mexico City. An original composite case record form was created to measure physical and sexual abuse before and during pregnancy. RESULT: Forty-one percent of respondents had a history of physical or sexual abuse, with current abuse reported by 11.1%, and abuse during pregnancy by 7.6%. Among abused women, 71% reported an increase in the severity of abuse since becoming pregnant. Logistic regression revealed physically fighting with a partner and a history of abuse best predict violence during pregnancy. CONCLUSION: The severity of abuse among abused women appears to increase during pregnancy. Prenatal care visits in Mexico are an important opportunity for violence screening and intervention.

Post-traumatic stress symptoms in children and adolescents with chronic pain: A topical review of the literature and a proposed framework for future research.

BACKGROUND AND OBJECTIVE: The co-occurrence of chronic pain and post-traumatic stress symptoms (PTSS) and post-traumatic stress disorder (PTSD) has gained increasing research attention. Studies on associations among pain and PTSS or PTSD in youth have largely been conducted in the context of acute injury or trauma. Less is known about the risk for co-occurrence with paediatric chronic pain. In this review, we (1) propose a conceptual framework to outline factors salient during childhood that may be associated with symptom severity, co-occurrence and mutual maintenance, (2) present relevant literature on PTSS in youth with acute and chronic pain and identify research gaps and (3) provide recommendations to guide paediatric research examining shared symptomatology. DATABASES AND DATA TREATMENT: Electronic databases (PubMed and Google Scholar) were used to identify relevant articles using the search terms 'child, adolescent, paediatric, chronic pain, acute pain, post-traumatic stress symptoms and post-traumatic stress disorder'. Studies were retrieved and reviewed based on relevance to the topic. RESULTS: Our findings revealed that existing biobehavioural and ecological models of paediatric chronic pain lack attention to traumatic events or the potential development of PTSS. Paediatric studies are also limited by lack of a conceptual framework for understanding the prevalence, risk and trajectories of PTSS in youth with chronic pain. CONCLUSIONS: Our new developmentally informed framework highlights individual symptoms and shared contextual factors that are important when examining potential associations among paediatric chronic pain and PTSS. Future studies should consider bidirectional and mutually maintaining associations, which will be aided by prospective, longitudinal designs. WHAT DOES THIS REVIEW ADD?: This review presents relevant literature on pain and PTSS in youth and proposes a conceptual framework to examine factors salient during childhood that may be associated with symptom severity, comorbidity and mutual maintenance of chronic pain and PTSS in paediatric populations. We highlight dynamic factors that may change across children's development and provide recommendations to guide paediatric research examining potential associations among PTSS and chronic pain.

Impact of recurrent and chronic pain on child and family daily functioning: a critical review of the literature.

The author reviewed the current status of research on the impact of recurrent and chronic pain on everyday functioning of children and families and organized the research findings around the specific life contexts (e.g., school, peers) that may be affected by pain. Although findings demonstrate that many different aspects of child and family life are affected by pain, the prevalence and severity of children's functional limitations associated with pain remain unknown. Few treatment studies for pediatric recurrent and chronic pain have focused on enhancing children's functioning. It has been shown, however, that functional outcomes can be improved by cognitive-behavioral interventions. Recommendations for research on functional outcomes and implications for clinical practice are discussed.

A review of behavioral screening practices in pediatric settings: do they pass the test?

We reviewed the current status of behavior screening methods, such as parental questionnaires, for identifying behavioral problems in children seen in pediatric settings. Information is organized around basic criteria for implementing screening procedures. We conclude that although use of parent-completed questionnaires, such as the Child Behavior Checklist and the Pediatric Symptom Checklist, can increase identification of child behavioral dysfunction in pediatric settings, it is unclear whether screening will cause a change in physician behaviors necessary to improve child functional outcomes. Clinical and research implications are discussed.

Psychosocial predictors of children's postoperative pain.

The purpose of this study was to investigate the influence of psychosocial variables in the prediction of children's pain intensity following surgery. Forty-two children, ages 7 to 17 years (M = 12.26, SD = 3.06), completed an interview 1 week prior to surgery assessing anticipatory distress related to their forthcoming surgery and history of coping strategy use. Following surgery, children reported the intensity of their pain using visual analog scales. Findings demonstrated that the majority of children experienced moderate to severe postoperative pain. Hierarchical multiple regression analyses revealed that psychosocial variables added to the prediction of children's postoperative pain after controlling for the influence of surgery-related and demographic variables. These findings lend initial support for the inclusion of psychosocial assessment measures (e.g., anticipatory surgery distress) in the preoperative assessment of pediatric patients who may be at risk for excessive postsurgical pain.

Social inequalities in vaccination uptake among children aged 0-59 months living in Madagascar: an analysis of Demographic and Health Survey data from 2008 to 2009.

BACKGROUND: Socioeconomic inequalities in vaccination can reduce the ability and efficiency of global efforts to reduce the burden of disease. Vaccination is particularly critical because the poorest children are often at the greatest risk of contracting preventable infectious diseases, and unvaccinated children may be clustered geographically, jeopardizing herd immunity. Without herd immunity, these children are at even greater risk of contracting disease and social inequalities in associated morbidity and mortality are amplified. METHODS: Data on vaccination for children under five came from the most recent Demographic and Health Survey in Madagascar (2008-2009). Vaccination status was available for diptheria, pertussis, tetanus, hepatitis B, measles, tuberculosis, poliomyelitis, and H. influenza type-B. Multilevel logistic regression was used to analyze childhood vaccination by parental socioeconomic status while accounting for shared district, cluster, and household variation. Maps were created to serve as a roadmap for efforts to increase vaccination. FINDINGS: Geographic variation in vaccination rates was substantial. Districts that were less covered were near other districts with limited coverage. Most districts lacked herd immunity for diphtheria, pertussis, poliomyelitis and measles. Full herd immunity was reached in a small number of districts clustered near the capital. While within-district variation in coverage was substantial; parental education and wealth were independently associated with vaccination. INTERPRETATION: Socioeconomic inequalities in vaccination reduce herd immunity and perpetuate inequalities by allowing infectious diseases to disproportionately affect the most vulnerable populations. Findings indicated that most districts had low immunization coverage rates and unvaccinated children were geographically clustered. The result was inequalities in vaccination and reduced herd immunity. To further improve coverage, interventions must take a multilevel approach that focuses on both supply- and demand-side barriers to delivering vaccination to underserved regions, and to the poorest children in those regions.

Reciprocal longitudinal associations between pain and depressive symptoms in adolescents.

BACKGROUND: Elevated depressive symptoms are common in youth with chronic pain, and pain symptoms are frequent in adolescents with depressive disorders. While studies have identified concurrent associations between pain and depression over time in youth, it is unclear how change in one symptom impacts change in the other symptom. METHODS: This three-time point 12-month longitudinal study examined reciprocal associations among pain and depression in a clinical sample of adolescents (12-18) diagnosed with chronic pain (n = 55) or a depressive disorder (n = 40). Mixed-effects multivariate models were used to test if changes over a preceding time interval predicted symptom severity at subsequent time points. Study group, age, sex, race, baseline pain intensity and baseline depressive symptoms were included as covariates. RESULTS: Generalized estimating equations revealed that pain and depressive symptoms were significantly associated over time (ß = 1.54; p < 0.001). As hypothesized, changes in pain were associated with subsequent depressive symptoms (ß = 1.16; p < 0.001). Conversely, changes in depressive symptoms predicted subsequent pain (ß = 0.026; p < 0.05), but with a weaker association. In the model predicting pain, an interaction between depressive symptoms and study group emerged (ß = -0.02; p < 0.05), with change in depressive symptoms having the greatest impact on pain in the depressed sample. CONCLUSIONS: Findings extend previous adult research to an adolescent sample showing changes in pain intensity are predictive of subsequent depressive symptoms. In comparison to adult data, changes in depressive symptoms had less impact on subsequent pain in youth. Future research can examine how targeting persistent pain may also aid the treatment of depressive symptoms in adolescents.

Community Partners for Healthy Farming Intervention Research.

The purpose of the Community Partners for Healthy Farming Intervention Research (CPHF-IR) program is to implement and evaluate existing or new interventions for reduction of agriculture-related injuries, hazards, and illnesses. Objectives include the development of active partnerships between experienced researchers, communities, workers, managers, agricultural organizations, agribusinesses, and other stakeholders. Specific intervention projects were selected by the competitive review process in response to a request for proposals. The second series of projects (funded 2000-2003) targeted: improved ergonomics for handling grapes (CA) and for small-scale berry growers (WI, IA, MI, MN), engineering controls (KY, VA, SC) and training (IN) related to tractors, private-sector financial incentives for safety (IA, NE), and reducing eye injuries in Latino farmworkers (IL, MI, FL). Partners have provided their unique resources for accessing the target population, planning, implementation, dissemination, and evaluation. They have produced useful engineering controls, educational and motivational tools, and helped build infrastructure for promoting agricultural health as essential to sustainable agriculture. Additional outcomes have included: increased interest among participants in collaborating in further research, the feasibility of Latino lay health advisors as active partners in research, and the value of process evaluation of a partnership to enhance intervention sustainability. NIOSH is utilizing the model created for Simple Solutions: Ergonomics for Farm Workers, a document related to earlier CPHF-IR projects, for a comparable document for construction in both English and Spanish. This program has confirmed that such partnerships can produce not only sustainable interventions but also products and models with the potential to expand farther geographically than originally anticipated and even into other sectors, e.g., for primary prevention among healthcare workers and adolescents, and to introduce public health in social studies and language classes.

Coalitions: partnerships to promote agricultural health and safety.

Throughout the 1990s, a variety of partnerships and community-based organizations have been formed with the primary mission to promote agricultural safety and health. These groups are altruistic, creative, energetic, and provide critical perspectives for improving the safety and health of the agricultural workforce at the local, regional, and national levels. These coalitions have been created as a result of philanthropic support, public funding, grassroots interest, and personal experiences with agricultural injuries andfatalities. They are playing important roles in collaborating with researchers and in reaching the individual agricultural communities. They have been instrumental in conducting needs assessments and are critical to the development and implementation of successful surveillance programs and interventions. Outreach and dissemination of research findings and other safety and health information to target audiences are strengths of these diverse coalitions. This article will focus on primarily community-based coalitions, providing an overview of the development, foci, membership activities, and contributions or impact of these groups during the 1990s and the challenges in maintaining and sustaining the coalitions. This information should be useful to those seeking to understand the activities of existing coalitions and identify potential partnerships for future activities.

Prediction of children's postoperative pain: the role of presurgical expectations and anticipatory emotions.

Examined predictors of children's ratings of postoperative pain intensity based on a model of children's expectations for surgery developed from the Children's Health Belief Model (Bush & Iannotti, 1990) and McGrath's (1990) model of children's pain experiences. Prior to their inpatient surgeries, 28 children (ages 7-17 years) and their parents completed ratings of children's expected surgery pain, anticipatory anxiety, and expected helpfulness of pain medicine. Following surgery, children completed ratings of their postoperative pain intensity. Age, total analgesics administered, and anticipatory anxiety emerged as significant predictors of children's postoperative pain ratings. Methodological issues concerning the measurement of children's expectations for surgery are discussed.

Treatment of functional impairment in severe somatoform pain disorder: a case example.

OBJECTIVE: To describe the assessment and treatment of severe functional impairment in a young female adolescent with somatoform pain disorder. METHODS: Treatment included an inpatient hospital admission using a rehabilitation approach and behavior modification program. Standardized assessment of functional impairment and health-related quality of life was performed at baseline and follow-up. Diagnostic evaluation and treatment costs were computed using insurance and hospital billing data. RESULTS: Pre-/postintervention measures of functional disability indicated significant improvement in physical and psychosocial functioning in everyday activities. Although costly, the inpatient admission decreased frequent health care use over the short term. CONCLUSIONS: Delay in diagnosis of somatoform disorders may seriously extend children's disability and require more intensive treatment. Functional disability is a critical measure of treatment outcome in children with severe somatoform disorder. Future research concerning interventions for children with a broad range of recurrent and chronic pain symptoms can be strengthened through a focus on reducing functional disability.

Parental presence during anaesthesia induction for outpatient surgery of the infant.

We conducted a randomized controlled trial of parental presence during anaesthesia induction for outpatient surgery in 73 infants (aged 1-12 months). Effects of parental presence on infant and parental outcomes, including anxiety, health care attitudes and satisfaction with the anaesthesia and surgery experience were evaluated. Results demonstrated that parental presence had no impact on infant behavioural distress during induction. In addition, parents who were present demonstrated comparable anxiety levels and health care attitudes before and after surgery, as well as comparable levels of satisfaction with the surgical experience compared to parents who were absent during induction. We discuss reasons for the lack of treatment effects from parental presence, and new directions for future research to identify subgroups of children who may most benefit from the opportunity to have parents involved in the perioperative period.

A psychological behavioral screening service: use, feasibility, and impact in a primary care setting.

OBJECTIVE: To describe a psychology behavioral screening service and the use of the service in subsequent primary care provider (PCP) treatment decisions. METHODS: The goal of the behavioral screening service was to obtain standardized parent and teacher rating scale data for children identified by PCPs as having possible behavioral problems. Medical chart review data were collected on 147 children for 1 year following screening to evaluate (1) PCP follow-up of the behavioral concern, (2) prescription of psychotropic medications, (3) referral to mental health services, and (4) receipt of mental health services. RESULTS: Children screened by this psychology service had clinically significant behavioral problems, according to both parent and teacher data; PCPs appeared to use screening results to guide decisions about medication prescription but not mental health referrals. Children with more behavioral problems were more likely to be prescribed psychotropic medications and to be seen by a mental health professional. CONCLUSIONS: These data suggest that a psychology behavioral screening service is feasible and may help guide PCP treatment decisions for children with behavior problems, particularly regarding the prescription of psychotropic medication.

Migraine headaches and sleep disturbances in children.

OBJECTIVE: The aim of the present study was to investigate the prevalence of sleep disturbances in children with migraine headaches and to describe individual differences in sleep behaviors based on headache features (eg, frequency, duration, intensity). BACKGROUND: A relationship between migraine headaches and sleep disturbances has been suggested in both children and adults, but there is a lack of research examining the relationship between specific headache features and the range of sleep behaviors in children. METHODS: One hundred eighteen children, aged 2 to 12 years (mean, 9.1; standard deviation, 2.3) were evaluated for headaches at two pediatric neurology departments. Parents completed the Children's Sleep Habits Questionnaire and a standardized questionnaire regarding headache characteristics. RESULTS: Parents reported a high rate of sleep disturbances in children, including sleeping too little (42%), bruxism (29%), child co-sleeping with parents (25%), and snoring (23%). Children with migraine headaches experienced more sleep disturbances compared to published healthy control norms. After controlling for child demographics, we found that the frequency and duration of migraine headaches predicted specific sleep disturbances, including sleep anxiety, parasomnias, and bedtime resistance. CONCLUSIONS: Children with migraine headaches have a high prevalence of sleep disturbances. The direction of the relationship between headaches and sleep is unknown. Regardless, interventions targeting sleep habits may improve headache symptoms, and effective treatment of headaches in children may positively impact sleep.

Predictors of a child's ability to use a visual analogue scale.

BACKGROUND: Visual analogue scales (VAS) are used to assess the strength of perceptions of both children and adults in many clinical and research settings. Although the VAS has been shown by some authors to be reliable for use by children aged 5 years and older, others have proposed that young children, generally < or =7 years of age, may not have the conceptual ability to use a VAS. OBJECTIVE: To identify demographic and cognitive variables that would maximize the accuracy of predicting children's abilities to use a VAS. METHODS: Forty kindergarten children performed a seriation task, used a VAS to perform a calibration task and completed the Block Design and Vocabulary subtests of the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R). An estimated IQ was calculated from the WPPSI-R subtest scores. Socioeconomic status was assessed using the Hollingshead Four Factor Index of Social Status. Logistic regression was used to determine the best predictive models. Sensitivity, specificity, negative predictive value, positive predictive value and accuracy were calculated for statistically significant predictive models. MAIN OUTCOME MEASURE: Successful completion of the calibration study by the child. RESULTS: Only 42% of the subjects could use a VAS. The subject's age (> or =5.6 years), combined with estimated IQ (> or =100), was the best predictor of a child's ability to use a VAS (88% accuracy). CONCLUSION: The majority of kindergarten children in our study could not complete a VAS accurately. Cognitive ability, combined with chronological age, was the best predictor of a child's accurate use of a VAS, as determined by logistic regression. Paediatric researchers may need to consider alternative rating scales to measure perceptions in children under 7 years of age.

Functional limitations of school-aged children seen in primary care.

OBJECTIVE: The purpose of the present study was to assess the prevalence of functional limitations in children seen in a large paediatric practice network and to identify sociodemographic, family and psychosocial factors related to functional limitations. STUDY DESIGN: Cross-sectional analysis. POPULATION: Children were recruited from two large, practice-based primary care research networks during their paediatric office visits. For the present study, participants included 14 630 school-aged children (ages 6-15 years) and their caregivers. OUTCOMES MEASURED: Parents completed written questionnaires including the Pediatric Symptom Checklist, the Family Apgar and the Functional Limitations Index. RESULTS: Findings indicated that 15% of children surveyed had some limitation in their daily functioning. More children had schoolwork and physical function limitations than limitations in personal and self-care. Logistic regression equations predicted functional limitations and health status in children from a model of sociodemographic factors, psychosocial symptoms and family functioning. CONCLUSIONS: A low but significant number of school-age children seen in the primary care setting experience functional limitations. Children with any psychosocial symptoms were at increased risk for functional limitations, indicating the critical need to screen for functional impairment in children with suspected behavioural or emotional problems. A screening tool of functional limitations may be useful for assessing the presence or absence of such limitations in children's daily function and warrants further investigation.