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We have computationally studied Mg x Zn 1-x SnN 2 alloy system in wurtzite structure using density functional theory and beyond. Cationic disorder of the random limit is chosen for modeling the crystal structure. Lattice mismatch of less than 1 % in the alloy system helps in the miscibility of Mg and Zn, thus making it widely useful in tandem solar cells. Electronic band gaps increase linearly with higher Mg concentration. These materials have hole effective masses significantly lower than electron effective masses. Considerable absorption together with a lower reflectivity can render this alloy an effective absorber. All the alloys are mechanically stable, but (x = 0.25) and (x = 0.50) are dynamically unstable. These alloys also exhibit large hardness. • Crystal structure for Mg x Zn 1-x SnN 2 simulated using special quasi-random structures (SQS). • Opto-electronic properties of computed with the hybrid HSE06 functional. • Hole effective masses lower than electron effective masses. • Band gaps increase with increase in Mg concentration. • Substantial absorption with lower reflectivity. [ABSTRACT FROM AUTHOR]

Seeks evidence to show that genetic recombination is a significant factor affecting the structure and dynamics of rice blast pathogen populations in the Himalayan region. Subdivision of the population into genetic lineages; Comparison with populations in other areas.

Reports on two patients with densely-vascularized, low-grade cerebellar glial tumors called angiogliomas or angiomatous gliomas. Use of the term angioglioma to describe several different categories of tumor which contain vascular elements; Composition of the tumors identified.

Addresses the physiological mechanisms underlying the detection of and response to environmental factors. Reviews the seasonal regulation of steroid-dependent and steroidological bases underlying photoperiodism and endogenous circannual behaviors and examines the possibility of seasonal fluctuations in human behavior and physiology, with particular reference to the phenomenology and putative mechanisms of Seasonal Affective Disorder (SAD).

Pays tribute to Brian Cummins, former consultant neurosurgeon at Frenchay Hospital in Bristol.

Highlights: [•] Light and dark pulses altered dendritic patterning of hippocampal neurons. [•] Light and dark pulses also affected dendritic spine density. [•] Hippocampal expression of fetal liver kinase 1 was decreased by a light pulse. [ABSTRACT FROM AUTHOR]

Among cancer patients, metabolic and sleep abnormalities are significant problems that are associated with decreased quality of life and increased mortality. In spite of the abundance of metabolic and sleep abnormalities in cancer patients, the mechanisms by which tumors alter metabolism and sleep remain unknown. Utilizing a non-metastatic murine breast cancer model, we investigated the relationships among immune, metabolic, and sleep abnormalities. Tumor bearing mice displayed increased serum interleukin-6 concentrations, concurrent with hyperglycemia, altered gluconeogenesis/glycolysis gene expression, and sleep abnormalities. To test whether tumor induced elevations in IL-6 were responsible for the metabolic and sleep abnormalities observed in our study, we reduced IL-6 signaling by administering a monoclonal antibody against IL-6. Despite successfully suppressing IL-6 signaling, metabolic and sleep abnormalities remained. Next, we investigated hypocretin/orexin (HO) signaling in the lateral hypothalamus as this population of neurons is known to regulate both metabolism and sleep, and observed increased HO activity. We administered a dual HO receptor antagonist (almorexant) to test whether the increased HO signaling was driving the altered hepatic glucose production and hyperglycemia. Administration of almorexant rescued the tumor-induced deficits in hyperglycemia, hepatic glucose production, and improved sleep quality, independent of IL-6. Together, our data demonstrate a novel mechanism by which non-metastatic tumors can promote energy availability, and suggest that targeting HO system may represent a potential intervention for breast cancer patients with metabolic dysfunctions. [ABSTRACT FROM AUTHOR]

The central Arctic Ocean is not isolated, but tightly connected to the northern Pacific and Atlantic Oceans. Advection of nutrient-, detritus- and plankton-rich waters into the Arctic Ocean forms lengthy contiguous domains that connect subarctic with the arctic biota, supporting both primary production and higher trophic level consumers. In turn, the Arctic influences the physical, chemical and biological oceanography of adjacent subarctic waters through southward fluxes. However, exports of biomass out of the Arctic Ocean into both the Pacific and Atlantic Oceans are thought to be far smaller than the northward influx. Thus, Arctic Ocean ecosystems are net biomass beneficiaries through advection. The biotic impact of Atlantic- and Pacific-origin taxa in arctic waters depends on the total supply of allochthonously-produced biomass, their ability to survive as adults and their (unsuccessful) reproduction in the new environment. Thus, advective transport can be thought of as trails of life and death in the Arctic Ocean. Through direct and indirect (mammal stomachs, models) observations this overview presents information about the advection and fate of zooplankton in the Arctic Ocean, now and in the future. The main zooplankton organisms subjected to advection into and inside the Arctic Ocean are (a) oceanic expatriates of boreal Atlantic and Pacific origin, (b) oceanic Arctic residents and (c) neritic Arctic expatriates. As compared to the Pacific gateway the advective supply of zooplankton biomass through the Atlantic gateways is 2–3 times higher. Advection characterises how the main planktonic organisms interact along the contiguous domains and shows how the subarctic production regimes fuel life in the Arctic Ocean. The main differences in the advective regimes through the Pacific and Atlantic gateways are presented. The Arctic Ocean is, at least in some regions, a net heterotrophic ocean that – during the foreseeable global warming trend – will more and more rely on an increasing local primary production while the advection of zooplankton, as revealed by models, will cease. [ABSTRACT FROM AUTHOR]

The authors reflect on on an editorial signed by a number of toxicology journal editors which argued for the status quo in endocrine disruptor (ED) regulation and suggest the dismissive approach is unfounded. They state both epidemiology and experimental animal studies have shown plausible causal links between ED and adverse health outcomes at very low doses. They suggest that policymakers need to base decisions on science instead of assumptions based on research on chemicals that aren't EDs.

Highlights: [•] Short days impair CA1 LTP, spatial learning & memory, and alter neuronal morphology. [•] Chronic melatonin implants reproduce effects of short days on hippocampal function. [•] Melatonin signaling drives photoperiodic plasticity in the hippocampus. [Copyright &y& Elsevier]

Abstract: In response to changing day lengths, small photoperiodic rodents have evolved a suite of adaptations to survive the energetic bottlenecks of winter. Among these adaptations are changes in metabolism, adiposity, and energy balance. Whereas hypothalamic and neuroendocrine regulation of these adaptations has been extensively studied, the impact of day length, and interaction of day length and stress, on the energy balance of neurons within the central nervous system remains unspecified. Thus, we exposed male Siberian hamsters (Phodopus sungorus) to either short or long day lengths for 14weeks to induce the full suite of adaptive responses, exposed them to 4h of restraint, and then measured relative mRNA expression in the hippocampus for low- and high-affinity glucocorticoid receptors (glucocorticoid receptor (GR), mineralocorticoid receptor (MR)), brain-derived neurotrophic factor (BDNF), and the neuron-specific glucose transporter GLUT3. Independent of photoperiod, restraint elevated plasma cortisol (CORT) concentrations and reduced expression of GR, MR, and BDNF. Neither restraint nor photoperiod significantly altered GLUT3 expression. Among all groups, plasma cortisol concentrations were negatively correlated with GR and MR expression. MR, BDNF, and GLUT3 levels were positively correlated with one another, even when controlling for photoperiod and CORT. Taken together, these results suggest that, as peripheral energy balance changes across day length in this photoperiodic species, the neurons of the hippocampus do not alter relative gene expression levels of three proteins involved in monitoring neuronal glucose regulation and morphology. [Copyright &y& Elsevier]

We document the recent reappearance of anadromous sockeye salmon () that were thought to have been extirpated by the construction of hydroelectric dams on the Coquitlam and Alouette rivers in British Columbia, Canada, in 1914 and 1927, respectively. Unexpected downstream migrations of juveniles during experimental water releases into both rivers in 2005 and 2006 preceded upstream return migrations of adults in 2007 and 2008. Genetic (microsatellite and mitochondrial DNA) markers and stable isotope (δ34S and 87Sr/86Sr) patterns in otoliths confirm that both the juvenile downstream migrants and adult upstream migrants were progeny of nonanadromous sockeye salmon (kokanee) that inhabit Coquitlam and Alouette reservoirs. Low genetic diversity and evidence of genetic bottlenecks suggest that the kokanee populations in both reservoirs originated from relatively few anadromous individuals that residualized after downstream migration was largely prevented by the construction of dams. Once given an opportunity for upstream and downstream migration, both populations appear capable of reverting to a successful anadromous form, even after 25 generations. [ABSTRACT FROM AUTHOR]

Abstract: Adult mammalian brains are capable of some structural plasticity. Although the basic cellular mechanisms underlying learning and memory are being revealed, extrinsic factors contributing to this plasticity remain unspecified. White-footed mice (Peromyscus leucopus) are particularly well suited to investigate brain plasticity because they show marked seasonal changes in structure and function of the hippocampus induced by a distinct environmental signal, viz., photoperiod (i.e. the number of hours of light/day). Compared to animals maintained in 16 h of light/day, exposure to 8 h of light/day for 10 weeks induces several phenotypic changes in P. leucopus, including reduction in brain mass and hippocampal volume. To investigate the functional consequences of reduced hippocampal size, we examined the effects of photoperiod on spatial learning and memory in the Barnes maze, and on long-term potentiation (LTP) in the hippocampus, a leading candidate for a synaptic mechanism underlying spatial learning and memory in rodents. Exposure to short days for 10 weeks decreased LTP in the Schaffer collateral–CA1 pathway of the hippocampus and impaired spatial learning and memory ability in the Barnes maze. Taken together, these results demonstrate a functional change in the hippocampus in male white-footed mice induced by day length. [ABSTRACT FROM AUTHOR]

Abstract: Rodents that live in changing environments display different immune responses mediated in part by photoperiod (day length) cues. Siberian hamsters maintained in winter-like (short) photoperiods display smaller physiological and behavioral responses to immune challenges as compared with hamsters housed in summer-like (long) photoperiods. We hypothesized that these different response patterns are attributable to altered cytokine production in the hypothalamus in response to photoperiod changes. Female hamsters were housed in long or short days for 10 weeks to induce photoperiodic alterations, then injected with either LPS (a bacterial endotoxin) or saline. Fever and food intake were assessed 3 h post-injection; hypothalami and blood were collected 3, 6, and 12 h post-injection. LPS induced lower fever and reduction in food intake responses in short-day hamsters as compared with long-day hamsters. Additionally, short-day hamsters reduced IL-1β and Tnfα expression in the hypothalamus 6 h after LPS injection, as measured by quantitative RT-PCR. Plasma estradiol concentrations did not differ between long- and short-day hamsters. These data suggest that differences in cytokine production in the hypothalamus may underlie the photoperiod-induced differences in sickness responses, and that these changes are not mediated by estradiol. [Copyright &y& Elsevier]

Sex differences in immune function are well documented. These sex differences may be modulated by social and environmental factors. Individuals of polygynous species generally exhibit more pronounced sex differences in immune parameters than individuals of monogamous species, often displaying an energetic trade-off between enhanced immunity and high mating success. During winter, animals contend with environmental conditions (e.g. low temperatures and decreased food availability) that evoke energetic-stress responses; many mammals restrict reproduction in response to photoperiod as part of an annual winter coping strategy. To test the hypothesis that extant sex and species differences in immune surveillance may be modulated by photoperiod, we examined leukocyte numbers in males and females of two closely related hamster species (Phodopus). As predicted, uniparental P. sungorus exhibited a robust sex difference, with total white blood cells, total lymphocytes, T cells, and B cells higher in females than males, during long days when reproduction occurs, but not during short days when reproduction usually stops. In contrast, biparental male and female P. campbelli exhibited comparable leukocyte numbers during both long and short days. To study sex differences in stress responses, we also examined immune cell trafficking in response to an acute (2 h) restraint stressor. During stressful challenges, it appears beneficial for immune cells to exit the blood and move to primary immune defense areas such as the skin, in preparation for potential injury or infection. Acute stress moved lymphocytes and monocytes out of the blood in all animals. Blood cortisol concentrations were increased in P. sungorus females compared to males at baseline (52%) and in response to restraint stress (38%), but only in long days. P. campbelli males and females exhibited comparable blood cortisol and stress responses during both long and short days. Our results suggest that interactions among social factors and the environment play a significant role in modulating sex and seasonal alterations in leukocyte numbers and stress responses. [Copyright &y& Elsevier]

Most permanent CNS damage following global cerebral ischemia is mediated by endogenous secondary processes. The trajectory of recovery is established early, suggesting that immediate recovery environment may play a critical role in post-ischemic damage. Hospitals are stressful environments, with high noise levels, continuous disruptions by staff, and unpredictable lighting. Physiological processes such as inflammation become deranged in disruptive lighting, which led us to hypothesize that cardiac arrest (CA) outcomes are negatively affected by exposure to light at night. Following a CA and cardiopulmonary resuscitation procedure or a SHAM procedure, mice were exposed to either a standard light/dark cycle (LD) or a light/dim light cycle (dLAN). Mortality was 4-fold higher among dLAN mice compared to LD mice in the week following CA. dLAN increased hippocampal cell death 1 week after CA. Hippocampal expression of pro-inflammatory cytokines was elevated 24h after CA. Moreover, among CA mice a single night of dLAN was sufficient to upregulate hippocampal expression of IL-1β and TNF-α compared to dark nights. dLAN-CA also increased hippocampal microglia activation and microglial pro-inflammatory cytokine expression compared to LD-CA. Post-CA corticosterone concentrations did not differ suggesting differences in outcome are not due to altered corticosterone. Blocking the inflammatory response and modulating light wavelength minimized light induced damage following CA. These results indicate that dLAN exacerbates damage following CA and may have implications for lighting in clinical settings. [ABSTRACT FROM AUTHOR]

Abstract Fever is initiated by activation of the arachidonic acid cascade and the biosynthesis of prostaglandins within the brain. Inducible cyclooxygenase (COX-2) is a rate-limiting enzyme in prostaglandin synthesis, and the number of blood vessels expressing COX-2 correlates with elevated body temperature following peripheral lipopolysaccharide (LPS). Despite its importance in host defense, fever is energetically expensive and we hypothesized that fever may be limited by available metabolic resources. During winter, when competing metabolic demands are constrained by low temperatures and food availability, it was predicted that fever duration would be reduced in seasonally breeding Siberian hamsters (Phodopus sungorus ). We measured LPS-induced COX-2 expression in blood vessels of hamsters to test whether photoperiodic alterations in fever duration are centrally mediated, or whether they reflect changes in peripheral modulation of body temperature. Hamsters housed in long, ‘summer-like’ or short, ‘winter-like’ day lengths for 10 weeks were injected with LPS, and brains were collected 2, 4, or 8 h later. COX-2 expression was comparably increased in long- and short-day hamsters by 2 h and 4 h post-LPS; however, short-day hamsters exhibited significantly fewer COX-2-positive cells and blood vessels by 8 h post-LPS compared to long-day hamsters, corresponding with reduced fever duration in short-day hamsters. Cortisol concentrations increased more than two-fold in short-day compared to long-day hamsters by 4 h; this increase may have contributed to the decrease in COX-2 expression observed by 8 h in short days. We conclude that short photoperiods significantly altered the time course of central COX-2 protein expression in hamsters in a manner consistent with reduced fever duration. [ABSTRACT FROM AUTHOR]