Does Prior Civilian Trauma Moderate the Relationship Between Combat Trauma and Post-deployment Mental Health Symptoms?

In addition to combat trauma, childhood and adult non-military, interpersonal trauma exposures have been linked to a range of psychiatric symptoms (e.g., alcohol use problems, posttraumatic stress disorder [PTSD], depression symptoms) in veterans. However, few studies simultaneously explore the associations between these civilian and combat trauma types and mental health outcomes. Using a sample of combat-exposed veterans who were previously deployed to Iraq and Afghanistan (N = 302), this study sought to (a) understand the independent associations of civilian interpersonal trauma (i.e., childhood trauma and non-military adult trauma) and combat-related trauma with post-deployment alcohol use, PTSD symptoms, and depressive symptoms, respectively and (b) to examine the interactive effects of trauma type to test whether childhood and non-military adult trauma moderate the association of combat trauma with these outcomes. A path analytic framework was used to allow for the simultaneous prediction of these associations. In the final model non-military adult trauma and combat trauma were found to be significantly associated with PTSD symptoms and depression symptoms, but not average amount of drinks consumed per drinking day. Childhood trauma was not associated with any outcomes (i.e., PTSD symptoms, depression symptoms, average amount of drinks consumed per day). Only combat trauma was significantly associated with average amount of drinks consumed per day. Results underscore the importance of assessing multiple trauma types and considering trauma as a non-specific risk factor, as different trauma types may differentially predict various mental health outcomes other than PTSD. Further, results highlight the noteworthiness of considering co-occurring outcomes within the veteran community. Limitations, future directions, and implications of diversity are discussed.

DECO: a framework for jointly analyzing de novo and rare case/control variants, and biological pathways

MOTIVATION

Rare variant-based analyses are beginning to identify risk genes for neuropsychiatric disorders and other diseases. However, the identified genes only account for a fraction of predicted causal genes. Recent studies have shown that rare damaging variants are significantly enriched in specific gene-sets. Methods which are able to jointly model rare variants and gene-sets to identify enriched gene-sets and use these enriched gene-sets to prioritize additional risk genes could improve understanding of the genetic architecture of diseases.

RESULTS

We propose DECO (Integrated analysis of de novo mutations, rare case/control variants and omics information via gene-sets), an integrated method for rare-variant and gene-set analysis. The method can (i) test the enrichment of gene-sets directly within the statistical model, and (ii) use enriched gene-sets to rank existing genes and prioritize additional risk genes for tested disorders. In simulations, DECO performs better than a homologous method that uses only variant data. To demonstrate the application of the proposed protocol, we have applied this approach to rare-variant datasets of schizophrenia. Compared with a method which only uses variant information, DECO is able to prioritize additional risk genes.

AVAILABILITY

DECO can be used to analyze rare-variants and biological pathways or cell types for any disease. The package is available on Github https://github.com/hoangtn/DECO.

Drinking Patterns of Post-Deployment Veterans: The Role of Personality, Negative Urgency, and Posttraumatic Stress

Rates of posttraumatic stress disorder (PTSD) and alcohol misuse are known to be high among post-deployment Veterans. Previous research has found that personality factors may be relevant predictors of post-deployment drinking, yet results have been inconsistent and may be influenced by the selection of drinking outcome. This study aimed to examine relations between PTSD, negative urgency, and the five factor models of personality with multiple alcohol consumption patterns, including maximum drinks in a day, number of binge drinking episodes, at-risk drinking, and average weekly drinks in a sample of 397 Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) Veterans. The pattern of results suggested that the association between personality, PTSD, and drinking may depend on which drinking outcome is selected. For example, maximum drinks in a day was significantly associated with younger age, male gender, low agreeableness, and an interaction between negative urgency and PTSD, whereas number of binge drinking days was significantly associated with younger age, extraversion, low agreeableness, and negative urgency. This study highlights the heterogeneity of drinking patterns among Veterans and the need for careful consideration and transparency of outcomes selection in alcohol research.

An Update on Precision Medicine Advances In Neurodevelopmental Disorders

Neurodevelopmental disorders, including autism spectrum disorder (ASD) and attention-deficit/hyper-activity disorder (ADHD), represent a group of conditions that manifest early in child development and produce impairments across multiple domains of functioning. Although a number of pharmacological and psychosocial treatments exist to improve the symptoms associated with these syndromes, treatment advances have lagged. The Precision Medicine Initiative was launched with the goal of revolutionizing medicine by progressing beyond the historical one-size-fits-all approach. In this review, we evaluate current research efforts to personalize treatments for ASD and ADHD. Most pharmacogenetic testing has focused on the cytochrome P450 enzyme family with a particular focus on CYP2D6 and CYP2C19, which are genes that produce an enzyme that acts as a key metabolizer of many prescribed medications. This article provides an update on the state of the field of pharmacogenetics and "therapy-genetics" in the context of ASD and ADHD, and it also encourages clinicians to follow US Food and Drug Administration recommendations regarding pharmacogenetic testing.

Sleep Quality Moderates the Relationship between Anxiety Sensitivity and PTSD Symptoms in Combat-exposed Veterans

Objective/Background: Posttraumatic stress disorder (PTSD) and related conditions (e.g., depression) are common in Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn (OEF/OIF/OND) veterans. High anxiety sensitivity (AS), defined as fear of anxiety and anxiety-related consequences, is related to greater PTSD and depressive symptoms; however, few studies have identified possible modifiers of these associations. The current study examined the moderating role of sleep quality in the associations between AS and PTSD and depressive symptoms. Participants: Participants were 155 OEF/OIF/OND community veterans ages 21-40 (12.3% women). Methods: Participants completed a semi-structured clinical interview for DSM-IV PTSD symptoms (Clinician Administered PTSD Scale; CAPS) and self-report measures of anxiety sensitivity (Anxiety Sensitivity Index), sleep quality (Pittsburgh Sleep Quality Index global score; PSQI), and depressive symptoms (Beck Depression Inventory-II; BDI-II). Results: Results of hierarchical linear regression models indicated that the main effects of AS and global PSQI score were significantly associated with greater PTSD and depressive symptoms (both with sleep items removed), above and beyond the covariates of trauma load and military rank. Sleep quality moderated the relationship between AS and PTSD symptoms (but not depressive symptoms), such that greater AS was associated with greater PTSD symptoms for individuals with good sleep quality, but not poor sleep quality. Conclusions: Sleep quality and AS account for unique variance in PTSD and depressive symptoms in combat-exposed veterans. AS may be less relevant to understanding risk for PTSD among combat-exposed veterans experiencing poor sleep quality.

mTADA is a framework for identifying risk genes from de novo mutations in multiple traits

Joint analysis of multiple traits can result in the identification of associations not found through the analysis of each trait in isolation. Studies of neuropsychiatric disorders and congenital heart disease (CHD) which use de novo mutations (DNMs) from parent-offspring trios have reported multiple putatively causal genes. However, a joint analysis method designed to integrate DNMs from multiple studies has yet to be implemented. We here introduce multiple-trait TADA (mTADA) which jointly analyzes two traits using DNMs from non-overlapping family samples. We first demonstrate that mTADA is able to leverage genetic overlaps to increase the statistical power of risk-gene identification. We then apply mTADA to large datasets of >13,000 trios for five neuropsychiatric disorders and CHD. We report additional risk genes for schizophrenia, epileptic encephalopathies and CHD. We outline some shared and specific biological information of intellectual disability and CHD by conducting systems biology analyses of genes prioritized by mTADA.

Examination of the effects of impulsivity and risk-taking propensity on alcohol use in OEF/OIF/OND Veterans

Introduction

A strong association between posttraumatic stress disorder (PTSD) and problematic alcohol use has been demonstrated among Veteran populations exposed to combat trauma. Several traits, such as higher levels of risk-taking propensity (RTP) and impulsivity (e.g., negative urgency [NU]), are associated with both increased PTSD symptom-atology and greater alcohol use problems.

Methods

The present study examined the effects of NU and RTP on alcohol use (measured by average weekly alcohol consumption and number of binge drinking days in 1 month), as well as their potential moderating effects on the association between PTSD symptom severity and alcohol use in a sample of Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) US Veterans. We hypothesized that NU and RTP would both significantly predict alcohol use and moderate the relation between PTSD symptom severity and alcohol use, such that the association between PTSD symptoms and alcohol use would be greater among individuals high compared to low in NU and RTP.

Results

As hypothesized, the main effects of RTP and NU were significantly positively associated with average weekly alcohol consumption and the number of binge drinking days in the past month. However, neither NU nor RTP moderated the relation between PTSD and either alcohol variable.

Discussion

NU and RTP may represent transdiagnostic risk markers for PTSD and alcohol use problems; however, the current study did not support an exploratory role of NU or RTP in the association between PTSD and alcohol use phenotypes.

The Nomological Network of a Behavioral Distress Tolerance Task in Veterans

There is a relative lack of research on distress tolerance (DT) in veteran samples. The aims of the study were to (a) evaluate convergent and discriminant validity of a behavioral measure of DT compared to theoretically similar (i.e., self-report DT, negative urgency) and dissimilar (i.e., risk-taking) constructs and (b) evaluate the concurrent validity of DT in relation to posttraumatic stress disorder (PTSD) and depressive symptoms in a veteran sample. A sample of U.S. veterans who served after the September 11, 2001 terror attacks (N = 306, 89.9% male; M age 30.2 years, SD = 4.5, range: 21-40 years) completed self-report and behavioral measures of DT, risk-taking, impulsivity, and depressive symptoms, and completed a clinical interview for PTSD. Results of a multitrait-multimethod matrix found significant yet minimal shared variance, r2 = .01-.03, ps = .002-.055, between the self-report and behavioral measures of DT. We used a series of multiple regressions to examine the relative contribution of the behavioral and self-report DT measures in the prediction of PTSD and depressive symptoms. Self-reported, but not behavioral, DT accounted for unique variance in PTSD, r2 = .12, p < .001, and depressive symptoms, r2 = .23, p < .001. Participants with PTSD or higher scores on measures of depression were more likely to report greater increases in frustration and irritability after completing the behavioral task. Results indicate that DT is not a unidimensional construct and must be considered in the context of specific emotions (e.g., tolerance of irritability vs. fear) and contexts (e.g., behavioral, affective).

Anxiety Sensitivity and Distress Tolerance Typologies and Relations to Posttraumatic Stress Disorder: A Cluster Analytic Approach

A growing literature suggests a relationship between a high anxiety sensitivity (AS; the fear of anxiety and its related consequences)/low distress tolerance (DT; the capacity tolerate internal negative states) profile and posttraumatic stress disorder (PTSD) symptoms. However, specific profiles have not been identified or examined specifically in veteran samples. Thus, the aims of the present study were to establish empirically derived profiles created from response patterns on the Anxiety Sensitivity Index and Distress Tolerance Scale and to examine associations with PTSD symptom clusters among a sample of combat-exposed veterans (N = 250). A cluster analytic approach was utilized to identify AS/DT profiles, and a series of MANOVAs with post hoc analyses was conducted to examine the relationship between each AS/DT profile and each PTSD symptom cluster. Results indicated a three-cluster solution including a high AS/low DT "at risk" profile, a low AS/high DT "resilient" profile, and an average AS/DT "intermediate" profile. The at-risk profile was associated with significantly greater symptoms in each PTSD cluster (i.e., hyperarousal, avoidance, re-experiencing) when compared to the other two profiles. The at-risk profile was also associated with greater depressive symptoms and lower self-reported resilience. These findings extend the previous literature by identifying a high AS/low DT "at risk" profile and its associations with PTSD symptoms, underscoring the potential utility in targeting these affect-regulation constructs for clinical intervention.

A cluster-analytic approach to determining drinking motives and personality typologies: Trauma group differences and respective relations to PTSD and problematic alcohol use

Veterans with posttraumatic stress disorder (PTSD) are at elevated risk for alcohol use problems, a relationship commonly explained by using alcohol to cope with unpleasant symptoms of PTSD. However, patterns of alcohol use motives, more broadly, have not been well characterized in veteran samples, nor have they been evaluated in the context of other relevant factors, such as normative personality traits. The aims of the present study were to identify empirically derived drinking motive and personality typologies to determine whether these typologies differ as a function of PTSD status (i.e., nontrauma control, trauma exposed-no PTSD, and PTSD) and to evaluate associations between typology and PTSD symptom severity and alcohol consumption, respectively. Cluster analyses identified a 4-cluster solution. Results indicated that these typologies differed significantly according to trauma group as well as across levels of PTSD symptom severity and alcohol use. Specifically, Cluster 4 represented individuals at highest risk for both PTSD symptom severity and alcohol use compared to all the other typologies; Cluster 1 demonstrated lowest risk for PTSD symptom severity and alcohol use compared to all other typologies; and although Clusters 2 and 3 did not differ according to PTSD symptom severity, individuals in Cluster 2 had significantly higher alcohol use. These results represent certain "at risk" versus "protective" typologies that may facilitate the identification of individuals at risk for comorbid PTSD and problematic alcohol use. (PsycINFO Database Record

Faraday-Shielded dc Stark-Shift-Free Optical Lattice Clock

We demonstrate the absence of a dc Stark shift in an ytterbium optical lattice clock. Stray electric fields are suppressed through the introduction of an in-vacuum Faraday shield. Still, the effectiveness of the shielding must be experimentally assessed. Such diagnostics are accomplished by applying high voltage to six electrodes, which are grounded in normal operation to form part of the Faraday shield. Our measurements place a constraint on the dc Stark shift at the 10^{-20} level, in units of the clock frequency. Moreover, we discuss a potential source of error in strategies to precisely measure or cancel nonzero dc Stark shifts, attributed to field gradients coupled with the finite spatial extent of the lattice-trapped atoms. With this consideration, we find that Faraday shielding, complemented with experimental validation, provides both a practically appealing and effective solution to the problem of dc Stark shifts in optical lattice clocks.

Relation between coping and posttrauma cognitions on PTSD in a combat-trauma population

Individual differences in cognitive processes and coping behaviors play a role in the development and maintenance of posttraumatic stress disorder (PTSD). Given the large numbers of combat-exposed service members returning from the Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND) conflicts, exploring individual differences in cognitive-affective processes is important for informing our understanding of PTSD etiology and early intervention in military samples. The present study examined the unique main and interactive effects of negative posttrauma cognitions (i.e., negative beliefs about self [NS], the world [NW], and self-blame [SB]) and coping strategies (i.e., positive behavioral, positive cognitive, avoidant coping, and social and emotional coping) on PTSD diagnosis within 155 (M_age = 30.7, SD = 4.48) OEF/OIF/OND combat trauma-exposed veterans recruited from an ongoing study examining the effects of combat trauma and stress reactivity. In the final, stepwise logistic regression analysis, avoidant coping, but no other coping strategy, was significantly positively related to PTSD diagnosis in the initial step. Higher levels of NS, but not NW, were significantly associated with having a PTSD diagnosis, while SB was associated with decreased likelihood of PTSD, above and beyond coping strategies. A significant interaction effect was found between NS and positive cognitive coping, such that greater positive cognitive coping weakened the relationship between NS and PTSD. Examining and addressing coping behaviors and negative thoughts of self jointly may benefit assessment and intervention approaches in a combat-trauma population.

The global therapist competence scale for youth psychosocial treatment: Development and initial validation

OBJECTIVE

We describe the development and initial psychometric properties of the observer-rated Global Therapist Competence Scale for Youth Psychosocial Treatment (G-COMP) in the context of cognitive-behavioral treatment (CBT) for youth anxiety disorders.

METHOD

Independent coders rated 744 sessions from a sample of 68 youth (mean age = 10.56 years) using the G-COMP and the instruments of alliance, involvement, CBT adherence, CBT competence.

RESULTS

Inter-rater reliability coefficients, ICC(2,2), were greater than .60 for the 5 G-COMP domain scores. G-COMP scores yielded small to medium correlations with instruments of alliance (rs = .17-.44) and youth involvement in treatment (rs = .08-.53), and medium to large correlations with instruments of CBT competence and adherence (rs = .26-.63). Therapists in the research setting were rated higher compared to newly trained therapists in community clinics.

CONCLUSION

Preliminary reliability and validity of the G-COMP are promising, but future research is needed with non-CBT samples.

Does Parenting Influence the Enduring Impact of Severe Childhood Sexual Abuse on Psychiatric Resilience in Adulthood?

This study examined the effect of parenting on the association between childhood sexual abuse (CSA) and psychiatric resilience in adulthood in a large female twin sample (n = 1423) assessed for severe CSA (i.e., attempted or completed intercourse before age 16). Severe CSA was associated with lower resilience to recent stressors in adulthood (defined as the difference between their internalizing symptoms and their predicted level of symptoms based on cumulative exposure to stressful life events). Subscales of the Parental Bonding Instrument were significantly associated with resilience. Specifically, parental warmth was associated with increased resilience while parental protectiveness was associated with decreased resilience. The interaction between severe CSA and parental authoritarianism was significant, such that individuals with CSA history and higher authoritarianism scores had lower resilience. Results suggest that CSA assessment remains important for therapeutic work in adulthood and that addressing parenting may be useful for interventions in children with a CSA history.

#cutting: Non-suicidal self-injury (NSSI) on Instagram

BACKGROUND

Social media presents an important means for social interaction, especially among adolescents, with Instagram being the most popular platform in this age-group. Pictures and communication about non-suicidal self-injury (NSSI) can frequently be found on the internet.

METHODS

During 4 weeks in April 2016, n = 2826 (from n = 1154 accounts) pictures which directly depicted wounds on Instagram were investigated. Those pictures, associated comments, and user accounts were independently rated for content. Associations between characteristics of pictures and comments as well as weekly and daily trends of posting behavior were analyzed.

RESULTS

Most commonly, pictures depicted wounds caused by cutting on arms or legs and were rated as mild or moderate injuries. Pictures with increasing wound grades and those depicting multiple methods of NSSI generated elevated amounts of comments. While most comments were neutral or empathic with some offering help, few comments were hostile. Pictures were mainly posted in the evening hours, with a small peak in the early morning. While there was a slight peak of pictures being posted on Sundays, postings were rather evenly spread across the week.

CONCLUSIONS

Pictures of NSSI are frequently posted on Instagram. Social reinforcement might play a role in the posting of more severe NSSI pictures. Social media platforms need to take appropriate measures for preventing online social contagion.

Hyperpolarizability and Operational Magic Wavelength in an Optical Lattice Clock

Optical clocks benefit from tight atomic confinement enabling extended interrogation times as well as Doppler- and recoil-free operation. However, these benefits come at the cost of frequency shifts that, if not properly controlled, may degrade clock accuracy. Numerous theoretical studies have predicted optical lattice clock frequency shifts that scale nonlinearly with trap depth. To experimentally observe and constrain these shifts in an ^{171}Yb optical lattice clock, we construct a lattice enhancement cavity that exaggerates the light shifts. We observe an atomic temperature that is proportional to the optical trap depth, fundamentally altering the scaling of trap-induced light shifts and simplifying their parametrization. We identify an "operational" magic wavelength where frequency shifts are insensitive to changes in trap depth. These measurements and scaling analysis constitute an essential systematic characterization for clock operation at the 10^{-18} level and beyond.

Psychosocial interventions for children and adolescents after man-made and natural disasters: a meta-analysis and systematic review

Children and adolescents are a vulnerable group to develop post-traumatic stress symptoms after natural or man-made disasters. In the light of increasing numbers of refugees under the age of 18 years worldwide, there is a significant need for effective treatments. This meta-analytic review investigates specific psychosocial treatments for children and adolescents after man-made and natural disasters. In a systematic literature search using MEDLINE, EMBASE and PsycINFO, as well as hand-searching existing reviews and contacting professional associations, 36 studies were identified. Random- and mixed-effects models were applied to test for average effect sizes and moderating variables. Overall, treatments showed high effect sizes in pre-post comparisons (Hedges' g = 1.34) and medium effect sizes as compared with control conditions (Hedges' g = 0.43). Treatments investigated by at least two studies were cognitive-behavioural therapy (CBT), eye movement desensitization and reprocessing (EMDR), narrative exposure therapy for children (KIDNET) and classroom-based interventions, which showed similar effect sizes. However, studies were very heterogenic with regard to their outcomes. Effects were moderated by type of profession (higher level of training leading to higher effect sizes). A number of effective psychosocial treatments for child and adolescent survivors of disasters exist. CBT, EMDR, KIDNET and classroom-based interventions can be equally recommended. Although disasters require immediate reactions and improvisation, future studies with larger sample sizes and rigorous methodology are needed.

Differences in Activation and Deactivation in Children with Sickle Cell Disease Compared with Demographically Matched Controls

BACKGROUND AND PURPOSE

Declines in both functional activation and functional connectivity have been reported in patients with sickle cell disease. In this study, we derived the functional and default mode responses to a word stem paradigm in age-, ethnicity-, and background-matched subjects with sickle cell disease and control groups, with the aim of testing whether both networks were similarly attenuated and whether the changes were related to physiologic parameters that characterize sickle cell disease.

MATERIALS AND METHODS

Both the functional and default mode responses were obtained from age- and background-matched controls and the sickle cell population by using a visually presented word stem paradigm on a 3T scanner.

RESULTS

We observed an attenuated response to both activation and deactivation in the sickle cell disease group. There were no significant differences in the activation response between the 2 groups for the contrast control > sickle cell disease; however, significant differences were observed in the medial parietal cortex, the auditory cortex, and the angular gyrus for the default mode. For the sickle cell group, a significant correlation between the activation z scores and the physiologic parameters was observed; for the deactivation, the results were not significant but the trend was similar.

CONCLUSIONS

The results indicate that the physiologic parameters modulate the activation in the expected fashion, but that the effect was weaker for deactivation. Given that significant differences between the 2 groups were only seen for deactivation, additional factors must modulate the deactivation in sickle cell disease.

Sleep Disturbances in OEF/OIF/OND Veterans: Associations with PTSD, Personality, and Coping

STUDY OBJECTIVES

Sleep disturbances are well documented in relation to trauma exposure and posttraumatic stress disorder (PTSD), but correlates of such disturbances remain understudied in veteran populations. We conducted a preliminary study of sleep disturbances in Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn veterans (n = 133; mean [standard deviation] age = 29.8 [4.7] y).

METHODS

Veterans were assigned to one of three groups based on responses to the Clinician Administered PTSD Scale: control (no trauma-exposure [TE] or PTSD), TE, and PTSD. Sleep disturbance was assessed using the Pittsburgh Sleep Quality Index (PSQI). Measures of resilience, trauma load, personality, coping, alcohol use, and mild traumatic brain injury were also assessed via self-report.

RESULTS

The PTSD group had significantly more disturbed sleep (PSQI global score mean = 8.94, standard deviation = 3.12) than control (mean = 5.27, standard deviation = 3.23) and TE (mean = 5.34, standard deviation = 3.17) groups, but there were no differences between TE and control. The same pattern emerged across most PSQI subscales. Results of linear regression analyses indicated that current smoking, Army (versus other military branches), neuroticism, and using substances to cope were all significant correlates of higher sleep disturbance, whereas post-deployment social support was associated with less sleep disturbance. However, when combined together into a model with PTSD status, only neuroticism and substance use coping remained significant as predictors of more disturbed sleep.

CONCLUSIONS

These initial findings suggest that TE itself may not be an independent risk factor for disturbed sleep in veterans, and that neurotic personality and a tendency to cope by using substances may partially explain sleep disturbance, above and beyond a diagnosis of PTSD.

Predicting the Transition From Acute Stress Disorder to Posttraumatic Stress Disorder in Children With Severe Injuries

INTRODUCTION

The purpose of this study was to examine predictors of risk for and the transition between acute stress disorder (ASD) and posttraumatic stress disorder (PTSD) in a longitudinal sample of youth with severe injuries admitted to the hospital. These data would assist with treatment and discharge planning.

METHODS

Youth were assessed for ASD during the initial hospital stay and were followed-up over an 18-month period for PTSD (n = 151). Youth were classified into four groups, including Resilient (ASD-, PTSD-), ASD Only (ASD+, PTSD-), PTSD Only (ASD-, PTSD+), and Chronic (ASD+, PTSD+). Demographic, psychiatric, social context, and injury-related factors were examined as predictors of diagnostic transition.

RESULTS

The results of multivariate analysis of variance and pairwise comparisons found that peritraumatic dissociation, gender, and socioeconomic status were significant predictors after controlling for multiple testing.

DISCUSSION

Results suggest that both within-child and contextual factors contribute to the longitudinal response to trauma in children. Clinicians should consider early screening and discharge planning, particularly for children most at risk.

Athletic injuries

Injuries are common in the various disciplines that make up the sport of athletics. Diagnosis depends on an accurate history and competent examination, possibly assisted by imaging techniques such as ultrasound, magnetic resolution imaging and computerized tomography. It is also important to consider the influence of various intrinsic and extrinsic factors in deciding on the mechanism of injury. Most acute injuries relate to overstretching of soft tissue, whereas overuse injuries reflect repetitive microtrauma with degenerative or inflammatory consequences. Steroid injections should be restricted to situations where inflammation predominates. Surgery may be required for specific acute injuries and when supervised rehabilitation over 6 months fails to resolve chronic injury. Following surgery, physical and psychological rehabilitation should be carefully planned.

Anomalous Broadening in Driven Dissipative Rydberg Systems

We observe interaction-induced broadening of the two-photon 5s-18s transition in ^{87}Rb atoms trapped in a 3D optical lattice. The measured linewidth increases by nearly 2 orders of magnitude with increasing atomic density and excitation strength, with corresponding suppression of resonant scattering and enhancement of off-resonant scattering. We attribute the increased linewidth to resonant dipole-dipole interactions of 18s atoms with blackbody induced population in nearby np states. Over a range of initial atomic densities and excitation strengths, the transition width is described by a single function of the steady-state density of Rydberg atoms, and the observed resonant excitation rate corresponds to that of a two-level system with the measured, rather than natural, linewidth. The broadening mechanism observed here is likely to have negative implications for many proposals with coherently interacting Rydberg atoms.

Hyperplastic and Neoplastic Changes in the Lungs of Rats Treated Concurrently with Chrysotile Asbestos and N-Nitrosoheptamethyleneimine

This study investigated the combined effect in rat lungs of simultaneous exposure to chrysotile asbestos and N-nitrosoheptamethyleneimine (NHMI), with the objective of determining the potential for chrysotile to promote or otherwise enhance the pathological responses to this potent rodent lung carcinogen. Groups of 15 or 20 male and female animals were treated with 0, 3, or 10 mg kg(-1) NHMI subcutaneously, once a week for 10 wk, plus either clean air (control) or 50 mg m(-3) chrysotile by nose-only inhalation for 4 wk. A broad range of pulmonary metaplastic, hyperplastic, and neoplastic lesions was observed. Effects were more marked in male than in female animals. NHMI treatment increased the incidence of hyperplastic lesions, with apparent augmentation by chrysotile exposure (not statistically significant). Similarly, a "promoting" effect of chrysotile in the induction of lung tumors was observed, with all but 2 of the 11 primary tumors detected being in animals treated with both NHMI and asbestos. However, this apparent interaction was again not confirmable statistically, probably because of the low number of observed tumors (stemming from premature termination of the experiment). The study results are in line with those of similar previous studies, which found a higher incidence of hyperplastic and neoplastic changes in animals treated with both nitrosamine and asbestos than in those given nitrosamine alone. It is proposed that the method described (with minor modification) could be used to investigate either (1) the ability of other inhaled particles to augment NHMI carcinogenicity, or (2) the propensity of other chemical carcinogens to interact with asbestos in the production of pulmonary neoplasms.

Genetic determinants of depression: recent findings and future directions

LEARNING OBJECTIVES

After participating in this activity, learners should be better able to: 1. Evaluate current evidence regarding the genetic determinants of depression 2. Assess findings from studies of gene-environment interaction 3. Identify challenges to gene discovery in depression Depression is one of the most prevalent, disabling, and costly mental health conditions in the United States and also worldwide. One promising avenue for preventing depression and informing its clinical treatment lies in uncovering the genetic and environmental determinants of the disorder as well as their interaction (G × E). The overarching goal of this review article is to translate recent findings from studies of genetic association and G × E related to depression, particularly for readers without in-depth knowledge of genetics or genetic methods. The review is organized into three major sections. In the first, we summarize what is currently known about the genetic determinants of depression, focusing on findings from genome-wide association studies (GWAS). In the second section, we review findings from studies of G × E, which seek to simultaneously examine the role of genes and exposure to specific environments or experiences in the etiology of depression. In the third section, we describe the challenges to genetic discovery in depression and promising strategies for future progress.

Testing the temporal relationship between maternal and adolescent depressive and anxiety symptoms in a community sample

Transactional models have been used to explain the relationship between maternal depression and child behavioral problems; however, few studies have examined transactional models for maternal depression and adolescent depression and anxiety. Using an autoregressive cross-lagged analysis, we examined the longitudinal association between maternal and adolescent depression to determine the extent to which maternal depression influences adolescent depression and anxiety, and vice versa, over the course of a 4-year period. Participants were a community sample of 277 mother-adolescent dyads with offspring 10 to 14 years of age at the 1st year used in the analyses (43.7% female; 35% African American, 2.9% Hispanic/Latino). Depressive symptoms were assessed using maternal self-report (Center for Epidemiological Studies-Depression Scale; Radloff, 1977), and adolescent depression and anxiety were assessed by self-report (Revised Child Anxiety and Depression Scale; Chorpita, Yim, Moffitt, Umemoto, & Francis, 2000). The final model, χ(2)(14) = 23.74, p = .05 (TLI = .97, CFI = .98, RMSEA = .05), indicated that maternal depression was significantly associated with adolescent depression 2 years later. Of interest, adolescent depression did not significantly predict maternal depression, and the association between maternal and adolescent depression was not moderated by gender, age, or ethnicity. The association between maternal depression and adolescent anxiety was weaker than that observed for adolescent depression. Results suggest that the transaction model of maternal depression may not extend to adolescent depression and anxiety. Furthermore, maternal depression can have an enduring effect on adolescent depression, and continued research and clinical monitoring over extended periods is warranted.

Trauma Exposure and Axis I Psychopathology: A Co-twin Control Analysis in Norwegian Young Adults

Broad associations between trauma exposure (TE) and Axis I psychopathology have been noted in the literature. However, it is not clear if TE is directly associated with Axis I disorders or if the relationship is better accounted for by familial factors (i.e., early environment and/or genetic factors). The current investigation used the co-twin control method in a large sample of adult twin pairs from the Norwegian Twin Registry (N = 2,776), including 449 twin pairs discordant for DSM-IV Criterion A TE. History of TE and Axis I psychopathology was assessed using DSM-IV based clinical interview. Results suggested that TE was significantly associated with greater likelihood of meeting criteria for major depression, dysthymia, anxiety, substance abuse, eating disorders, and somatization disorder in the general population (odds ratios [OR] ranging from 1.33 to 2.21). Among twins discordant for TE, results suggested that TE may exert a direct influence on major depression, dysthymia, anxiety, substance abuse, eating disorders, and somatization disorder. Shared familial effects may also account for at least some of the relationship between TE and major depression. TE may play an important role in the development of a wide range of Axis I psychopathology above and beyond familial factors. Research and clinical implications are discussed.

Pre-typhoon socioeconomic status factors predict post-typhoon psychiatric symptoms in a Vietnamese sample

PURPOSE

Exposure to natural disasters has been associated with increased risk for various forms of psychopathology. Evidence indicates that socioeconomic status (SES) may be important for understanding post-disaster psychiatric distress; however, studies of SES-relevant factors in non-Western, disaster-exposed samples are lacking. The primary aim of the current study was to examine the role of pre-typhoon SES-relevant factors in relation to post-typhoon psychiatric symptoms among Vietnamese individuals exposed to Typhoon Xangsane.

METHODS

In 2006, Typhoon Xangsane disrupted a mental health needs assessment in Vietnam in which the Self Reporting Questionnaire-20 (SRQ-20), and the Demographic and Health Surveys Wealth Index, a measure of SES created for use in low-income countries, were administered pre-typhoon. The SRQ-20 was re-administered post-typhoon.

RESULTS

Results of a linear mixed model indicated that the covariates of older age, female sex, and higher levels of pre-typhoon psychiatric symptoms were associated with higher levels of post-typhoon psychiatric symptoms. Analysis of SES indicators revealed that owning fewer consumer goods, having lower quality of household services, and having attained less education were associated with higher levels of post-typhoon symptoms, above and beyond the covariates, whereas quality of the household build, employment status, and insurance status were not related to post-typhoon psychiatric symptoms.

CONCLUSION

Even after controlling for demographic characteristics and pre-typhoon psychiatric symptoms, certain SES factors uniquely predicted post-typhoon psychiatric distress. These SES characteristics may be useful for identifying individuals in developing countries who are in need of early intervention following disaster exposure.

Factor structure of measures of anxiety and depression symptoms in African American youth

Previous research has suggested that the factor structure of anxiety measures is different in African American samples compared to majority population samples. However, these findings may be due to misuse of analytic methods rather than meaningful differences in the underlying presentation of anxiety. To address this, we examined the factor structure of two measures of child anxiety: the Revised Children's Anxiety and Depression Scale and the Multidimensional Anxiety Scale for Children in a sample of 229 African American youth. Contrary to previous research, confirmatory factor analyses yielded good fit for the original factor structures of both measures. These results suggest that the underlying factor structure of these measures may not be significantly different for African American and majority population youth as previously thought. The effect of data analytic procedures on subsequent conclusions and theory is discussed and recommendations are made.

White matter damage in asymptomatic patients with sickle cell anemia: screening with diffusion tensor imaging

BACKGROUND AND PURPOSE

Ischemic injury to the brain is a common complication of SCA. To better understand the neurologic impact of SCA, TBSS were applied to DTI data to investigate white matter injuries in pediatric patients with SCA.

MATERIALS AND METHODS

TBSS comparisons of a range of anisotropy and diffusion measures were carried out between age- and background-matched population groups: patients with SCA with no visible lesions, patients with SCA with mild gliosis, and normal controls.

RESULTS

TBSS analysis revealed that both SCA populations exhibited reduced anisotropy and increased diffusivity compared with normal controls in multiple brain regions, including the corpus callosum and centrum semiovale. Furthermore, the results suggest that the severity of SCA is positively correlated with the white matter changes in the corpus callosum.

CONCLUSIONS

The study demonstrates that TBSS is a viable technique in detecting subtle white matter damage in patients with SCA whose conventional anatomic MR imaging scans show no, or minimal, abnormalities and has the potential to evaluate the neurologic impact of the treatment of SCA.

Optimization of a free-fall reactor for the production of fast pyrolysis bio-oil

A central composite design of experiments was performed to optimize a free-fall reactor for the production of bio-oil from red oak biomass. The effects of four experimental variables including heater set-point temperature, biomass particle size, sweep gas flow rate and biomass feed rate were studied. Heater set-point temperature ranged from 450 to 650 °C, average biomass particle size from 200 to 600 μm, sweep gas flow rate from 1 to 5 sL/min and biomass feed rate from 1 to 2 kg/h. Optimal operating conditions yielding over 70 wt.% bio-oil were identified at a heater set-point temperature of 575 °C, while feeding red oak biomass sized less than 300 μm at 2 kg/h into the 0.021 m diameter, 1.8m tall reactor. Sweep gas flow rate did not have significant effect on bio-oil yield over the range tested.

Process optimization of an auger pyrolyzer with heat carrier using response surface methodology

A 1 kg/h auger reactor utilizing mechanical mixing of steel shot heat carrier was used to pyrolyze red oak wood biomass. Response surface methodology was employed using a circumscribed central composite design of experiments to optimize the system. Factors investigated were: heat carrier inlet temperature and mass flow rate, rotational speed of screws in the reactor, and volumetric flow rate of sweep gas. Conditions for maximum bio-oil and minimum char yields were high flow rate of sweep gas (3.5 standard L/min), high heat carrier temperature (∼600 °C), high auger speeds (63 RPM) and high heat carrier mass flow rates (18 kg/h). Regression models for bio-oil and char yields are described including identification of a novel interaction effect between heat carrier mass flow rate and auger speed. Results suggest that auger reactors, which are rarely described in literature, are well suited for bio-oil production. The reactor achieved liquid yields greater than 73 wt.%.

{gamma}-Tubulin and microtubule organization during meiosis in the liverwort Ricciocarpus natans (Ricciaceae)

Extant liverworts are "living fossils" considered sister to all other plants and as such provide clues to the evolution of the microtubule organizing center (MTOC) in anastral cells. This report is the first on microtubule arrays and their γ-tubulin-nucleating sites during meiosis in a member of the Ricciales, a specialized, species-rich group of complex thalloid (marchantioid) liverworts. In meiotic prophase, γ-tubulin becomes concentrated at several sites adjacent to the nuclear envelope. Microtubules organized at these foci give rise to a multipolar prometaphase spindle. By metaphase I, the spindle has matured into a bipolar structure with truncated poles. In both first and second meiosis, γ-tubulin forms box-like caps at the spindle poles. γ-Tubulin moves from spindle poles to the proximal surfaces of telophase chromosomes where interzonal microtubules are nucleated. Although a phragmoplast is organized, no cell plate is deposited, and second division occurs simultaneously in the undivided sporocyte. γ-Tubulin surrounds each of the tetrad nuclei, and phragmoplasts initiated between both sister and nonsister nuclei direct simultaneous cytokinesis. The overall pattern of meiosis (unlobed polyplastidic sporocytes, nuclear envelope MTOC, multipolar spindle origin, spindles with box-like poles, and simultaneous cytokinesis) more closely resembles that of Conocephalum than other marchantiod liverworts.

Efficacy of memantine on behavioral and psychological symptoms related to dementia: a systematic meta-analysis

BACKGROUND

The behavioral and psychological symptoms related to dementia (BPSD) are difficult to manage and are associated with adverse patient outcomes.

OBJECTIVE

To systematically analyze the data on memantine in the treatment of BPSD.

METHODS

We searched MEDLINE, EMBASE, Pharm-line, the Cochrane Centre Collaboration, www.clinicaltrials.gov, www.controlled-trials.com, and PsycINFO (1966-July 2007). We contacted manufacturers and scrutinized the reference sections of articles identified in our search for further references, including conference proceedings. Two researchers (IM and CF) independently reviewed all studies identified by the search strategy. We included 6 randomized, parallel-group, double-blind studies that rated BPSD with the Neuropsychiatric Inventory (NPI) in our meta-analysis. Patients had probable Alzheimer's disease and received treatment with memantine for at least one month. Overall efficacy of memantine on the NPI was established with a t-test for the average difference between means across studies, using a random effects model.

RESULTS

Five of the 6 studies identified had NPI outcome data. In these 5 studies, 868 patients were treated with memantine and 882 patients were treated with placebo. Patients on memantine improved by 1.99 on the NPI scale (95% Cl -0.08 to -3.91; p = 0.041) compared with the placebo group.

CONCLUSIONS

Initial data appear to indicate that memantine decreases NPI scores and may have a role in managing BPSD. However, there are a number of limitations with the current data; the effect size was relatively small, and whether memantine produces significant clinical benefit is not clear.

Polar organizers and girdling bands of microtubules are associated with gamma-tubulin and act in establishment of meiotic quadripolarity in the hepatic Aneura pinguis (Bryophyta)

Meiosis in Aneura pinguis is preceded by extensive cytoplasmic preparation for quadripartitioning of the diploid sporocyte into a tetrad of haploid spores. In early prophase the four future spore domains are defined by lobing of the cytoplasm and development of a quadripolar prophase spindle focused at polar organizers (POs) centered in the lobes. Cells entering the reproductive phase become isolated and, instead of hooplike cortical microtubules, have endoplasmic microtubule systems centered on POs. These archesporial cells proliferate by mitosis before entering meiosis. In prophase of each mitosis, POs containing a distinct concentration of gamma-tubulin appear de novo at tips of nuclei and initiate the bipolar spindle. Cells entering meiosis become transformed into quadrilobed sporocytes with four POs, one in each lobe. This transition is a complex process encompassing assembly of two opposite POs which subsequently disperse into intersecting bands of microtubules that form around the central nucleus. The girdling bands define the future planes of cytokinesis and the cytoplasm protrudes through the restrictive bands becoming quadrilobed. Two large POs reappear in opposite cleavage furrows. Each divides and the resulting POs migrate into the tetrahedral lobes of cytoplasm. Cones of microtubules emanating from the four POs interact to form a quadripolar microtubule system (QMS) that surrounds the nucleus in meiotic prophase. The QMS is subsequently transformed into a functionally bipolar metaphase spindle by migration of poles in pairs to opposite cleavage furrows. These findings contribute to knowledge of microtubule organization and the role of microtubules in spatial regulation of cytokinesis in plants.

Peripheral-type benzodiazepine receptor in neurosteroid biosynthesis, neuropathology and neurological disorders

The peripheral-type benzodiazepine receptor is a mitochondrial protein expressed at high levels in steroid synthesizing tissues, including the glial cells of the brain. Peripheral-type benzodiazepine receptor binds cholesterol with high affinity and is a key element of the cholesterol mitochondrial import machinery responsible for supplying the substrate cholesterol to the first steroidogenic enzyme, thus initiating and maintaining neurosteroid biosynthesis. Neurosteroid formation and metabolism of steroid intermediates are critical components of normal brain function. Peripheral-type benzodiazepine receptor also binds with high affinity various classes of compounds. Upon ligand activation peripheral-type benzodiazepine receptor-dependent cholesterol transport into mitochondria is accelerated leading in increased formation of neuroactive steroids. These steroids, such as allopregnanolone, have been shown to be involved in various neurological disorders, such as anxiety and mood disorders. Thus, peripheral-type benzodiazepine receptor drug ligand-induced neuroactive steroid formation offers a means to regulate brain dysfunction. Peripheral-type benzodiazepine receptor basal expression is upregulated in a number of neuropathologies, including gliomas and neurodegenerative disorders, as well as in various forms of brain injury and inflammation. In Alzheimer's disease pathology neurosteroid biosynthesis is altered and a decrease in the intermediate 22R-hydroxycholesterol levels is observed. This steroid was found to exert neuroprotective properties against beta-amyloid neurotoxicity. Based on this observation, a stable spirostenol derivative showing to display neuroprotective properties was identified, suggesting that compounds developed based on critical intermediates of neurosteroid biosynthesis could offer novel means for neuroprotection. In conclusion, changes in peripheral-type benzodiazepine receptor and neurosteroid levels are part of the phenotype seen in neuropathology and neurological disorders and offer potential targets for new therapies.

Adsorption of arsenic(V) by activated carbon prepared from oat hulls

The efficiency of self-manufactured activated carbon (AC) produced from oat hulls in adsorbing arsenic(V) was tested in a batch reactor. The results indicated that the adsorptive capacity of AC was affected by initial pH value, with adsorption capacity decreasing from 3.09 to 1.57 mg As g(-1) AC when the initial pH values increased from 5 to 8. A modified linear driving force model conjugated with a Langmuir isotherm was created to describe the study's kinetics. The test results show that rapid adsorption and slow adsorption exist simultaneously when AC is used to remove arsenic(V).

Gamma-tubulin and microtubule organization during microsporogenesis in Ginkgo biloba

This is the first report on gamma-tubulin and microtubule arrays during microsporogenesis in a gymnosperm. Meiosis in Ginkgo biloba is polyplastidic, as is typical of the spermatophyte clade, and microtubule arrays are organized at various sites during meiosis and cytokinesis. In early prophase, a cluster of gamma-tubulin globules occurs in the central cytoplasm adjacent to the off-center nucleus. These globules diminish in size and spread over the surface of the nucleus. A system of microtubules focused on the gamma-tubulin forms a reticulate pattern in the cytoplasm. As the nucleus migrates to the center of the microsporocyte, gamma-tubulin becomes concentrated at several sites adjacent to the nuclear envelope. Microtubules organized at these foci of gamma-tubulin give rise to a multipolar prophase spindle. By metaphase I, the spindle has matured into a distinctly bipolar structure with pointed poles. In both first and second meiosis, gamma-tubulin becomes distributed throughout the metaphase spindles, but becomes distinctly polar again in anaphase. In telophase I, gamma-tubulin moves from polar regions to the proximal surface of chromosome groups/nuclei where interzonal microtubules are organized. No cell wall is deposited and the interzonal microtubules embrace a plate of organelles between the two nuclear cytoplasmic domains (NCDs) of the dyad. Following second meiosis, phragmoplasts that form between sister and non-sister nuclei fuse to form a complex six-sided structure that directs simultaneous cytokinesis. Gamma-tubulin becomes associated with nuclei after both meiotic divisions and is especially conspicuous in the distal hemisphere of each young microspore where an unusual encircling system of cortical microtubules develops.

Economic analysis of selected lignocellulose-to-ethanol conversion technologies

The objective of this case study was to examine the economics of three lignocellulose-to-ethanol conversion technologies: fast pyrolysis integrated with a fermentation step, simultaneous saccharification and fermentation (SSF), and dilute sulfuric acid hydrolysis and fermentation. All technologies were assumed to have an annual production rate of 25 million gallons of ethanol. The three technologies were compared in terms of capital costs, operating costs, and ethanol production costs. Sensitivity analyses were carried out to study the uncertainties of wood costs and ethanol production rates on ethanol production costs. Final economic analysis showed that fast pyrolysis integrated with a fermentation step is comparable with the other two processes and suggests that it should be considered for further development.

Survey of the biological effects of refractory ceramic fibres: overload and its possible consequences

This paper summarizes the biological effects of refractory ceramic fibres (RCFs). RCFs are aluminosilicate glass insulation wools with similar chemical properties to other synthetic vitreous fibres (SVFs) or 'man-made vitreous fibres' (MMVFs). There is concern that RCFs could be significantly more pathogenic than other SVFs. This paper critically reviews the data on which this perception is based. Morbidity studies on workers in RCF manufacturing indicated that, in the United states, RCF exposure was associated with an increased incidence of pleural plaques and in both the united states and Europe with statistically significant changes in some measures of lung function (though not at present exposure levels). No interstitial fibrosis was found. An ongoing mortality study of limited statistical power has failed to indicate any increased incidence of lung cancer or mesothelioma. Findings in several early animal studies led to a large series of inhalation studies where rats exposed to high levels of RCF developed fibrosis and tumours but not those exposed to other SVFs. Similarly hamsters exposed to one sample (RCF1) developed mesothelioma. Subsequent analyses of the data indicated that the RCF used in these experiments had a significantly greater proportion of non-fibrous particles than those present in the other types of SVFs tested or in workplace air. Short-term studies indicated that pulmonary overload occurred at the same as RCF tissue burdens as those in the long-term animal bioassay. When RCFs were prepared in the same way as the other SVFs, a sample resulted with a more representative ratio of particles to fibres; this sample did not produce overload in short-term tests. SVFs have various abilities to persist in the lung tissue and thus accumulate to varying degrees. It is suggested that biopersistence is a key property. While RCFs are among the more persistent they are similar to many other fibre types. The scientific and regulatory implications of these findings are examined.

Gamma-tubulin localization changes from discrete polar organizers to anastral spindles and phragmoplasts in mitosis of Marchantia polymorpha L

Unlike the astral mitotic spindle that is organized at discrete centriolar centrosomes, the spindle of land plants is typically anastral and its origin has remained obscure. Gamma tubulin (gamma-tubulin), an important component of the centrosome, has been demonstrated at microtubule-nucleating sites in plant cells. Mitotic spindles of certain hepatics are initiated at distinct acentriolar polar organizers (POs) that appear de novo at the onset of mitosis. Data on the relationship of gamma-tubulin to POs and to microtubule arrays throughout the cell cycle were collected from rapidly dividing cells of Marchantia polymorpha (Bryophyta) that were triple-stained for gamma-tubulin, microtubules, and nuclei. POs at opposite ends of the elongated nucleus in early prophase stain brightly for gamma-tubulin and astral microtubules emanating from them initiate the spindle. As the spindle develops, however, the gamma-tubulin becomes dispersed from the highly concentrated spherical form of the POs to more diffusely organized cups at tips of the fusiform nucleus. By the end of prophase, all astral microtubules have disappeared and the gamma-tubulin is located in several minipoles along the now broad polar regions of the spindle. At metaphase, gamma-tubulin extends into the spindle itself. By telophase, the gamma-tubulin has migrated from distal to proximal surfaces of the sister nuclei and extends into the phragmoplast. Upon completion of cytokinesis, gamma-tubulin appears diminished and surrounds the nuclear envelopes. These data show that gamma-tubulin is only briefly concentrated in the PO, migrates in a cell-cycle-specific manner, and is consistently present at all putative sites of microtubule nucleation.

Steam activation of chars produced from oat hulls and corn stover

Oat hulls and corn stover were used to produce chars at approximately 500 degrees C. The carbon concentrations of oat hull char and corn stover chars produced were 72.3 and 68.0 wt.%, respectively. Both activation burn-off and Brunauer-Emmett-Teller (BET) surface area appear to exhibit a linear relationship with respect to activation time of oat hulls. As to corn stover activated carbons, there is no linear relationship between activation time and BET surface area. However, activation burn-off of and activation time appear to relate in a linear manner for the activated carbons produced from corn stover chars. Oat hull is better than corn stover as a raw material for the production of activated carbon.

Application of thermophilic enzymes in commercial biotransformation processes

Biocatalysis is a useful tool in the provision of chiral technology and extremophilic enzymes are just one component in that toolbox. Their role is not always attributable to their extremophilic properties; as with any biocatalyst certain other criteria should be satisfied. Those requirements for a useful biocatalyst will be discussed including issues of selectivity, volume efficiency, security of supply, technology integration, intellectual property and regulatory compliance. Here we discuss the discovery and commercialization of an l-aminoacylase from Thermococcus litoralis, the product of a LINK project between Chirotech Technology and the University of Exeter. The enzyme was cloned into Escherichia coli to aid production via established mesophilic fermentation protocols. A simple downstream process was then developed to assist in the production of the enzyme as a genetically modified-organism-free reagent. The fermentation and downstream processes are operated at the 500 litre scale. Characterization of the enzyme demonstrated a substrate preference for N-benzoyl groups over N-acetyl groups. The operational parameters have been defined in part by substrate-concentration tolerances and also thermostabilty. Several examples of commercial biotransformations will be discussed including a process that is successful by virtue of the enzyme's thermotolerance.

A dose-response model for refractory ceramic fibers

Refractory ceramic fibers (RCFs) are man-made vitreous fibers commonly used in insulation applications above 1000 degrees C. Although they have been subjected to considerable toxicologic evaluation, only the pooled results from two rat inhalation studies provide data that may be suitable for performing a numerical risk assessment. Even in these inhalation studies, good evidence exists that the maximum tolerated dose (MTD) was exceeded and that pulmonary overload occurred, a condition that will cause tumors whatever the dust responsible. Indeed, a significant yield of tumors was only obtained at the highest dose tested. If these results are omitted, there is no statistically significant evidence of carcinogenicity within the RCF results. Although there is little evidence that overload-related tumors are relevant to human risk, we adopted a conservative approach to obtain the estimates of risk regardless of overload, using a biologically based model, the two-stage clonal expansion model, as well as various statistical models, including the benchmark dose model. We argue that the data favor the use of a biologically based model, which gives the best fit when the highest dose RCF exposures are omitted. Continuing with this model, we show that available data from the RCF experiment, less outliers, coupled with results from other experiments with man-made mineral fibers (MMVFs), demonstrate that all MMVFs are potentially carcinogenic, with any risk mediated by the fibers' biopersistence. Application of this "all MMVF data set" model yields a maximum likely estimate for RCF excess unit risk of 4.6 x 10(-5) (95% upper confidence limit = 9.2 x 10(-5) per fiber/ml). This implies that the risk from occupational exposure to RCFs at 1 fiber/ml for a typical working lifetime would not exceed 10(-4).

TETRASPORE encodes a kinesin required for male meiotic cytokinesis in Arabidopsis

A key step in pollen formation is the segregation of the products of male meiosis into a tetrad of microspores, each of which develops into a pollen grain. Separation of microspores does not occur in tetraspore (tes) mutants of Arabidopsis thaliana, owing to the failure of male meiotic cytokinesis. tes mutants thus generate large 'tetraspores' containing all the products of a single meiosis. Here, we report the positional cloning of the TES locus and details of the role played by the TES product in male cytokinesis. The predicted TES protein includes an N-terminal domain homologous to kinesin motors and a C-terminus with little similarity to other proteins except for a small number of plant kinesins. These include the Arabidopsis HINKEL protein and NACK1 and two from tobacco (Nishihama et al., 2002), which are involved in microtubule organization during mitotic cytokinesis. Immunocytochemistry shows that the characteristic radial arrays of microtubules associated with male meiotic cytokinesis fail to form in tes mutants. The TES protein therefore is likely to function as a microtubule-associated motor, playing a part either in the formation of the radial arrays that establish spore domains following meiosis, or in maintaining their stability.

Events during the first four rounds of mitosis establish three developmental domains in the syncytial endosperm of Arabidopsis thaliana

Endosperm begins development as a single fertilized cell that undergoes many rounds of mitosis without cytokinesis resulting in a syncytium. The multinucleate cytoplasm is organized by nucleus-based radial microtubule systems into nuclear-cytoplasmic domains. When microtubules are organized into mitotic spindles, the integrity of the common cytoplasm is maintained by an unaltered network of filamentous actin. The first four rounds of mitosis result in the establishment of three developmental domains within the common cytoplasm. The spindles of the first two rounds of mitosis are oriented parallel to the long axis of the central cell, resulting in four nuclear-cytoplasmic domains in a filamentous arrangement. A switch in spindle orientation occurs in the third round of mitosis; all four spindles are oriented perpendicular to the long axis resulting in eight nuclear-cytoplasmic domains arranged in two adjacent files. Whereas the first three rounds of mitosis are synchronous, the fourth occurs as a wave of successive mitoses that begins at the micropylar pole. By the 16-nuclei stage, differences in nuclear shape, cytoskeletal arrays, and cytoplasmic characteristics mark the differentiation of the syncytium into micropylar, central, and chalazal developmental chambers. Nuclei in the micropylar chamber are fusiform and sheathed by parallel microtubules that flare from their tips, while those in the central and chalazal chambers are spherical. Nuclei in the central chamber are surrounded by radial microtubule systems, while those in the chalaza are enmeshed in a reticulum of microtubules. Whereas the cytoplasm in both micropylar and chalazal chambers is dense and nearly nonvacuolate, the syncytium in the central chamber consists of a single layer of evenly spaced nuclear-cytoplasmic domains surrounding a large central vacuole.