An improvement of Southwell's method for determining buckling loads

If an elastic bar with some initial imperfection is subjected to increasing compressive axial load, the lateral deflection, measured anywhere along its length, increases monotonically; the primary buckling mode becoming more and more dominant in the deflected shape. A classical approximate technique, due to R.V. Southwell, correlates axial load and lateral deflection for determination of the primary buckling load of the bar. However, Southwell's approximation may be inaccurate is the primary mode does not predominate in the deflected shape. The present thesis proposes a technique which employs axial loading, but also transverse loading to insure dominance of the primary mode in the deflected shape. The technique allows experimental determination of the second buckling load, again using appropriate transverse loads to insure dominance of that mode in the deflected shape.http://archive.org/details/improvementofsou00hendEnsign, United States NavyApproved for public release; distribution is unlimited

IgG light chain-independent secretion of heavy chain dimers: consequence for therapeutic antibody production and design

Rodent monoclonal antibodies with specificity towards important biological targets are developed for therapeutic use by a process of humanisation. This process involves the creation of molecules, which retain the specificity of the rodent antibody but contain predominantly human coding sequence. Here we show that some humanised heavy chains can fold, form dimers and be secreted even in the absence of light chain. Quality control of recombinant antibody assembly in vivo is thought to rely upon folding of the heavy chain CH1 domain. This domain acts as a switch for secretion, only folding upon interaction with the light chain CL domain. We show that the secreted heavy-chain dimers contain folded CH1 domains and contribute to the heterogeneity of antibody species secreted during the expression of therapeutic antibodies. This subversion of the normal quality control process is dependent upon the heavy chain variable domain, is prevalent with engineered antibodies and can occur when only the Fab fragments are expressed. This discovery will impact on the efficient production of both humanised antibodies as well as the design of novel antibody formats

2015 Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adultsa

These guidelines are intended for use by infectious disease specialists, orthopedic surgeons, neurosurgeons, radiologists, and other healthcare professionals who care for patients with native vertebral osteomyelitis (NVO). They include evidence and opinion-based recommendations for the diagnosis and management of patients with NVO treated with antimicrobial therapy, with or without surgical interventio

Exploring factors influencing low back pain in people with non-dysvascular lower limb amputation: a national survey

Background: Chronic low back pain (LBP) is a common musculoskeletal impairment in people with lower limb amputation. Given the multifactorial nature of LBP, exploring the factors influencing the presence and intensity of LBP is warranted. Objective: To investigate which physical, personal, and amputee-specific factors predicted presence and intensity of low back pain (LBP) in persons with non-dysvascular transfemoral (TFA) and transtibial amputation (TTA). Design: A retrospective cross-sectional survey. Setting: A national random sample of people with non-dysvascular TFA and TTA. Participants: Participants (N = 526) with unilateral TFA and TTA due to non-dysvascular aetiology (i.e. trauma, tumours, and congenital causes) and a minimum prosthesis usage of one year since amputation were invited to participate in the survey. The data from 208 participants (43.4% response rate) were used for multivariate regression analysis Methods (Independent variables): Personal (i.e. age, body mass, gender, work status, and presence of comorbid conditions), amputee-specific (i.e. level of amputation, years of prosthesis use, presence of phantom limb pain, residual limb problems, and non-amputated limb pain), and physical factors (i.e. pain provoking postures including standing, bending, lifting, walking,sitting, sit-to stand, and climbing stairs). Main outcome measures (Dependent variables): LBP presence and intensity. Results: A multivariate logistic regression model showed that the presence of two or more comorbid conditions (prevalence odds ratio (POR) = 4.34, p = .01), residual limb problems (POR 22 = 3.76, p<.01), and phantom limb pain (POR = 2.46, p = .01) influenced the presence of LBP. Given the high LBP prevalence (63%) in the study, there is a tendency for overestimation of PORand the results must be interpreted with caution. In those with LBP, the presence of residual limb problems (beta = 0.21, p = .01), and experiencing LBP symptoms during sit-to-stand task (beta = 0.22, p = .03) were positively associated with LBP intensity, while being employed demonstrated a negative association (beta = - 0.18, p = .03) in the multivariate linear regression model. Conclusions: Rehabilitation professionals should be cognisant of the influence that comorbid conditions, residual limb problems, and phantom pain have on the presence of LBP in people with non-dysvascular lower limb amputation. Further prospective studies could investigate the underlying causal mechanisms of LBP

Substrate age and tree islands influence carbon and nitrogen dynamics across a retrogressive semiarid chronosequence

The long-term dynamics of carbon (C) and nitrogen (N) in semiarid ecosystems remain poorly understood. We measured pools and fluxes of surface soil C and N, as well as other soil properties, under tree canopies and in intercanopy spaces at four sites that form a volcanic substrate age gradient in semiarid piñon-juniper woodlands of northern Arizona, United States. Clay content and soil water-holding capacity increased consistently with substrate age, but both soil organic C and N increased only up to the 750,000 year site and then declined at the oldest (3,000,000 year) site. Measures of soil C and N flux displayed a similar pattern to total C and N pools. Pools and fluxes of C and N among the three canopy types became more homogeneous with substrate age up to the 750,000 year site, but disparity between tree and intercanopy microsites widened again at the oldest site. The δ15N of both tree leaves and surface soils became progressively more enriched across the substrate age gradient, consistent with a N cycle increasingly dominated by isotope fractionating losses. Our results point to consistencies in patterns of ecosystem development between semiarid and more humid ecosystems and suggest that pedogenic development may be an important factor controlling the spatial distribution of soil resources in semiarid ecosystems. These data should help both unify and broaden current theory of terrestrial ecosystem development

Unique Features of a Global Human Ectoparasite Identified Through Sequencing of the Bed Bug Genome

The bed bug, Cimex lectularius, has re-established itself as a ubiquitous human ectoparasite throughout much of the world during the past two decades. This global resurgence is likely linked to increased international travel and commerce in addition to widespread insecticide resistance. Analyses of the C. lectularius sequenced genome (650 Mb) and 14,220 predicted protein-coding genes provide a comprehensive representation of genes that are linked to traumatic insemination, a reduced chemosensory repertoire of genes related to obligate hematophagy, host-symbiont interactions, and several mechanisms of insecticide resistance. In addition, we document the presence of multiple putative lateral gene transfer events. Genome sequencing and annotation establish a solid foundation for future research on mechanisms of insecticide resistance, human-bed bug and symbiont-bed bug associations, and unique features of bed bug biology that contribute to the unprecedented success of C. lectularius as a human ectoparasite

Unique features of a global human ectoparasite identified through sequencing of the bed bug genome

The bed bug, Cimex lectularius, has re-established itself as a ubiquitous human ectoparasite throughout much of the world during the past two decades. This global resurgence is likely linked to increased international travel and commerce in addition to widespread insecticide resistance. Analyses of the C. lectularius sequenced genome (650 Mb) and 14,220 predicted protein-coding genes provide a comprehensive representation of genes that are linked to traumatic insemination, a reduced chemosensory repertoire of genes related to obligate hematophagy, host–symbiont interactions, and several mechanisms of insecticide resistance. In addition, we document the presence of multiple putative lateral gene transfer events. Genome sequencing and annotation establish a solid foundation for future research on mechanisms of insecticide resistance, human–bed bug and symbiont–bed bug associations, and unique features of bed bug biology that contribute to the unprecedented success of C. lectularius as a human ectoparasite

Data compatibility in the addiction sciences: An examination of measure commonality

The need for comprehensive analysis to compare and combine data across multiple studies in order to validate and extend results is widely recognized. This paper aims to assess the extent of data compatibility in the substance abuse and addiction (SAA) sciences through an examination of measure commonality, defined as the use of similar measures, across grants funded by the National Institute on Drug Abuse (NIDA) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Data were extracted from applications of funded, active grants involving human-subjects research in four scientific areas (epidemiology, prevention, services, and treatment) and six frequently assessed scientific domains. A total of 548 distinct measures were cited across 141 randomly sampled applications. Commonality, as assessed by density (range of 0–1) of shared measurement, was examined. Results showed that commonality was low and varied by domain/area. Commonality was most prominent for (1) diagnostic interviews (structured and semi-structured) for substance use disorders and psychopathology (density of 0.88), followed by (2) scales to assess dimensions of substance use problems and disorders (0.70), (3) scales to assess dimensions of affect and psychopathology (0.69), (4) measures of substance use quantity and frequency (0.62), (5) measures of personality traits (0.40), and (6) assessments of cognitive/neurologic ability (0.22). The areas of prevention (density of 0.41) and treatment (0.42) had greater commonality than epidemiology (0.36) and services (0.32). To address the lack of measure commonality, NIDA and its scientific partners recommend and provide common measures for SAA researchers within the PhenX Toolkit

Is (poly-) substance use associated with impaired inhibitory control? A mega-analysis controlling for confounders.

Many studies have reported that heavy substance use is associated with impaired response inhibition. Studies typically focused on associations with a single substance, while polysubstance use is common. Further, most studies compared heavy users with light/non-users, though substance use occurs along a continuum. The current mega-analysis accounted for these issues by aggregating individual data from 43 studies (3610 adult participants) that used the Go/No-Go (GNG) or Stop-signal task (SST) to assess inhibition among mostly "recreational" substance users (i.e., the rate of substance use disorders was low). Main and interaction effects of substance use, demographics, and task-characteristics were entered in a linear mixed model. Contrary to many studies and reviews in the field, we found that only lifetime cannabis use was associated with impaired response inhibition in the SST. An interaction effect was also observed: the relationship between tobacco use and response inhibition (in the SST) differed between cannabis users and non-users, with a negative association between tobacco use and inhibition in the cannabis non-users. In addition, participants' age, education level, and some task characteristics influenced inhibition outcomes. Overall, we found limited support for impaired inhibition among substance users when controlling for demographics and task-characteristics