Effects of ionizing radiation on charge-coupled imagers

The effects of ionizing radiation on three different charge coupled imagers have been investigated. Device performance was evaluated as a function of total gamma ray dose. The principal failure mechanisms have been identified for each particular device structure. The clock and bias voltages required for high total dose operation of the devices are presented

Ancestral genome estimation reveals the history of ecological diversification in Agrobacterium

Horizontal gene transfer (HGT) is considered as a major source of innovation in bacteria, and as such is expected to drive adaptation to new ecological niches. However, among the many genes acquired through HGT along the diversification history of genomes, only a fraction may have actively contributed to sustained ecological adaptation. We used a phylogenetic approach accounting for the transfer of genes (or groups of genes) to estimate the history of genomes in Agrobacterium biovar 1, a diverse group of soil and plant-dwelling bacterial species. We identified clade-specific blocks of cotransferred genes encoding coherent biochemical pathways that may have contributed to the evolutionary success of key Agrobacterium clades. This pattern of gene coevolution rejects a neutral model of transfer, in which neighboring genes would be transferred independently of their function and rather suggests purifying selection on collectively coded acquired pathways. The acquisition of these synapomorphic blocks of cofunctioning genes probably drove the ecological diversification of Agrobacterium and defined features of ancestral ecological niches, which consistently hint at a strong selective role of host plant rhizospheres

Performance of a repetitive task by aged rats leads to median neuropathy and spinal cord inflammation with associated sensorimotor declines

Epidemiological studies have demonstrated a relationship between advancing age and susceptibility to risk factors for median neuropathies and musculoskeletal disorders. In this study, we determined if performance of a voluntary reaching task by aged rats induced sensorimotor declines, median nerve dysfunction and increased inflammatory cytokines in peripheral nerves, muscle and spinal cord neurons. Aged (14 mon) rats were trained for 15 min/day for 4 weeks to learn a high repetition, low force (HRLF) task (19 reaches/min; 15% maximum pulling force). Aged task rats performed the task for 2 h/day, 3 days/wk, for 12 weeks (until they were 18 mon of age). No behavioral changes were detected in normal controls (NC) or food-restricted controls (FR C) as they aged. However, grip strength declined in HRLF rats in weeks 6-12 (P\u3c0.01 each) and 12-week trained-only rats (TR; P\u3c0.05), compared to NC. Mechanical hypersensitivity was present in weeks 9 and 12 HRLF reach limb forepaws (P\u3c0.01 and P\u3c0.05, respectively), and 12-week HRLF support limb forepaws (P\u3c0.01) and hindpaws (P=0.03), compared to NC. By week 12, median nerve conduction velocity declined 23%, bilaterally, in HRLF (P\u3c0.001 each), and 13% in TR (P\u3c0.05), compared to NC. Tumor necrosis factor alpha (TNFα) increased in 12-week HRLF muscle (P=0.005), median nerve (P\u3c0.01), and neurons in superficial lamina of HRLF cervical spinal cords (P\u3c0.01), compared to NC. interleukin 1 beta (IL1β) also increased in superficial lamina neurons (P\u3c0.01). Loss of grip strength was correlated with median nerve conduction slowing (r=0.70) as well as increased nerve and muscle TNFα (r=-0.38 and r=-0.41, respectively); decrease in forepaw withdrawal thresholds was correlated with median nerve conduction slowing (r=0.81), increased nerve TNFα (r=-0.59), and increased TNFα and IL1β in neurons in spinal cord dorsal horns (r=-0.52 and r=-0.47, respectively). Thus, aged rats performing a repetitive task exhibited sensorimotor declines that were associated with decreased median nerve conduction, and increased pro-inflammatory cytokines in the median nerve and cervical spinal cord neurons

Solution of Three-Constraint Entropy-Based Velocity Distribution

A two-dimensional velocity profile based upon the principle of maximum entropy (POME) for wide open channel flows is presented. The derivation is based on the conservation of mass and momentum. The resulting profile involves three parameters that are determined from observations of mean velocity and the velocity at the water surface. The velocity profile is verified using field data in a river with a live bed. A comparison with three existing methods shows that the profile presented is the most accurate of the three, especially near the bed

Prevalence of and risk factors for suicidal ideation in adolescents during the COVID-19 pandemic: a cross-sectional study.

Pandemic-related life changes may have had a deleterious impact on suicidal behaviours. Early detection of suicidal ideation and identification of subgroups at increased risk could help prevent suicide, one of the leading causes of death among adolescents worldwide. Here, we aimed to investigate the prevalence of and risk factors for suicidal ideation in adolescents using a population-based sample from Switzerland, two years into the pandemic. Between December 2021 and June 2022, adolescents aged 14 to 17 years already enrolled in a population-based cohort study (State of Geneva, Switzerland) were asked about suicidal ideation over the previous year. In addition to a regression model, we conducted a network analysis of exposures which identified direct and indirect risk factors for suicidal ideation (i.e. those connected through intermediate risk factors) using mixed graphical models. Among 492 adolescents, 14.4% (95% CI: 11.5-17.8) declared having experienced suicidal ideation over the previous year. Using network analysis, we found that high psychological distress, low self-esteem, identifying as lesbian, gay or bisexual, suffering from bullying, extensive screen time and a severe COVID-19 pandemic impact were major risk factors for suicidal ideation, with parent-adolescent relationship having the highest centrality strength in the network. Our results show that a significant proportion of adolescents experience suicidal ideation, yet these rates are comparable with pre-pandemic results. Providing psychological support is fundamental, with a focus on improving parent-adolescent relationships

Direct association between rainfall and non-typhoidal <i>Salmonella</i> bloodstream infections in hospital-admitted children in the Democratic Republic of Congo

Abstract Non-typhoidal Salmonella (NTS) ranks first among causes of bloodstream infection in children under five years old in the Democratic Republic of Congo and has a case fatality rate of 15%. Main host-associated risk factors are Plasmodium falciparum malaria, anemia and malnutrition. NTS transmission in sub-Saharan Africa is poorly understood. NTS bloodstream infections mostly occur during the rainy season, which may reflect seasonal variation in either environmental transmission or host susceptibility. We hypothesized that environment- and host-associated factors contribute independently to the seasonal variation in NTS bloodstream infections in children under five years old admitted to Kisantu referral hospital in 2013–2019. We used remotely sensed rainfall and temperature data as proxies for environmental factors and hospital data for host-associated factors. We used principal component analysis to disentangle the interrelated environment- and host-associated factors. With timeseries regression, we demonstrated a direct association between rainfall and NTS variation, independent of host-associated factors. While the latter explained 17.5% of NTS variation, rainfall explained an additional 9%. The direct association with rainfall points to environmental NTS transmission, which should be explored by environmental sampling studies. Environmental and climate change may increase NTS transmission directly or via host susceptibility, which highlights the importance of preventive public health interventions

Soluble RAGE in COPD, with or without coexisting obstructive sleep apnoea

Background: Hypoxia can reduce the levels of soluble receptor for advanced glycation end-products (sRAGE), a new anti-inflammatory biomarker of COPD. We assessed sRAGE in patients with hypoxia-related diseases such as COPD, OSA and OSA-COPD overlap. Methods: Plasma levels of sRAGE were measured in 317 subjects at baseline (57 heathy nonsmokers HNS], 84 healthy smokers HS], 79 OSA, 62 COPD and 35 OSA-COPD overlap patients) and in 294 subjects after one year of follow-up (50 HNS, 74 HS, 77 OSA, 60 COPD and 33 overlap). Results: After adjusting for age, sex, smoking status and body mass index, sRAGE levels showed a reduction in OSA (- 12.5%, p = 0.005), COPD (- 14.8%, p < 0.001) and OSA-COPD overlap (- 12.3%, p = 0.02) compared with HNS. There were no differences when comparing sRAGE plasma levels between overlap patients and those with OSA or COPD alone. At follow-up, sRAGE levels did not change significantly in healthy subjects, COPD and OSA or OSA-COPD overlap nontreated with continuous positive airway pressure (CPAP). Moreover, in patients with OSA and OSA-COPD overlap who were treated with CPAP, sRAGE increased significantly. Conclusions: The levels of sRAGE are reduced in COPD and OSA. Treatment with CPAP appears to improve sRAGE levels in patients with OSA who also had COPD

Ambipolar gate effect and low temperature magnetoresistance of ultrathin La0.8Ca0.2MnO3 Films

Ultrathin La0.8Ca0.2MnO3 films have been measured in a field-effect geometry. The electric field due to the gate produces a large ambipolar decrease in resistance at low temperatures. This is attributed to the development of a pseudogap in the density of states and the couple of localized charge to strain. The gate effect and mangetoresistance are interpreted in a consistent framework. The implications for the low temperature behavior of a manganite film in the two dimensional limit are discussed.Comment: 4 pages, 3 figure

Characterization of Nonjunctional Hemichannels in Caterpillar Cells

Recent studies have demonstrated that hemichannels, which form gap junctions when paired from apposing cells, may serve additional roles when unpaired including cell adhesion and paracrine communication. Hemichannels in mammals are formed by connexins or pannexins, while in insects they are formed by pannexin homologues termed innexins. The formation of functional gap junctions by insect innexins has been established, although their ability to form functional nonjunctional hemichannels has not been reported. Here the characteristics of nonjunctional hemichannels were examined in three lepidopteran cell types, two cell lines (High Five and Sf9) and explanted hemocytes from Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae). Selective fluorescent dye uptake by hemichannels was observed in a significant minority of cells, using fluorescence microscopy and flow cytometry. Carbenoxelone, an inhibitor of mammalian junctions, disrupted dye uptake, while flufenamic acid and mefloquine did not. The presence of Ca2+ and Mg2+ in the media increased hemichannel activity. Additionally, lipopolysaccharide, a stimulator of immune activity in lepidopterans, decreased dye uptake. These results demonstrate for the first time the activity of nonjunctional hemichannels in insect cells, as well as pharmacological tools to manipulate them. These results will facilitate the further examination of the role of innexins and nonjunctional hemichannels in insect cell biology, including paracrine signaling, and comparative studies of mammalian pannexins and insect innexins