Fern species richness along a central Himalayan elevational gradient, Nepal

Aim The study explores fern species richness patterns along a central Himalayan elevational gradient (100–4800 m a.s.l.) and evaluates factors influencing the spatial increase and decrease of fern richness. Location The Himalayas stretch from west to east by 20°, i.e. 75–95° east, and Nepal is located from 80 to 88° east in this range. Methods We used published data of the distribution of ferns and fern allies to interpolate species elevational ranges. Defining species presence between upper and lower elevation limit is the basis for richness estimates. The richness pattern was regressed against the total number of rainy days, and gradients that are linearly related to elevation, such as length of the growing season, potential evapotranspiration (PET, energy), and a moisture index (MI = PET/mean annual rainfall). The regressions were performed by generalized linear models. Results A unimodal relationship between species richness and elevation was observed, with maximum species richness at 2000 m. Fern richness has a unimodal response along the energy gradients, and a linear response with moisture gradients. Main conclusions The study confirms the importance of moisture on fern distributions as the peak coincides spatially with climatic factors that enhance moisture levels; the maximum number of rainy days and the cloud zone. Energy‐related variables probably control species richness directly at higher elevations but at the lower end the effect is more probably related to moisture.     

Synthesis of robust tunable oscillators using mitogen activated protein kinase cascades

Mitogen activated protein kinase (MAPK) cascade is evolutionally preserved in all eukaryotic cells, and regulates various cellular activities such as gene expression, mitosis, differentiation, and apoptosis. Recently, Bashor et al. have shown that Ste5 scaffold protein can be used to reshape the MAPK cascade through engineered feedback loops, and have used heuristic tuning mechanisms to synthesize the feedback. A problem of interest is to determine whether information regarding the underlying biochemical reactions can be used to synthesize robust feedback that will ensure that the resultant circuit has the desired properties. In this paper, we consider the problem of engineering feedback in MAPK cascade to synthesize an oscillator of the desired frequency. Our approach builds on the MAPK cascade model derived by Chikarmane et al. who have exploited the existence of a Hopf bifurcation point in the Markevich model of the MAPK cascade to synthesize the exciting kinase as a function of the doubly phosphorylated protein. We show how the L₁\mathcal{L}_1-control theory can be used for a robust synthesis of the oscillator and present the simulation results.     

Projecting future grassland productivity to assess the sustainability of potential biofuel feedstock areas in the Greater Platte River Basin

This study projects future (e.g., 2050 and 2099) grassland productivities in the Greater Platte River Basin (GPRB) using ecosystem performance (EP, a surrogate for measuring ecosystem productivity) models and future climate projections. The EP models developed from a previous study were based on the satellite vegetation index, site geophysical and biophysical features, and weather and climate drivers. The future climate data used in this study were derived from the National Center for Atmospheric Research Community Climate System Model 3.0 ‘SRES A1B’ (a ‘middle’ emissions path). The main objective of this study is to assess the future sustainability of the potential biofuel feedstock areas identified in a previous study. Results show that the potential biofuel feedstock areas (the more mesic eastern part of the GPRB) will remain productive (i.e., aboveground grassland biomass productivity >2750 kg ha^?1 year^?1) with a slight increasing trend in the future. The spatially averaged EPs for these areas are 3519, 3432, 3557, 3605, 3752, and 3583 kg ha^?1 year^?1 for current site potential (2000–2008 average), 2020, 2030, 2040, 2050, and 2099, respectively. Therefore, the identified potential biofuel feedstock areas will likely continue to be sustainable for future biofuel development. On the other hand, grasslands identified as having no biofuel potential in the drier western part of the GPRB would be expected to stay unproductive in the future (spatially averaged EPs are 1822, 1691, 1896, 2306, 1994, and 2169 kg ha^?1 year^?1 for site potential, 2020, 2030, 2040, 2050, and 2099). These areas should continue to be unsuitable for biofuel feedstock development in the future. These future grassland productivity estimation maps can help land managers to understand and adapt to the expected changes in future EP in the GPRB and to assess the future sustainability and feasibility of potential biofuel feedstock areas.     

Interactions between antimalarial indolone-N-oxide derivatives and human serum albumin

The binding affinity of human serum albumin (HSA) to three antimalarial indolone-N-oxide derivatives, INODs, was investigated under simulated physiological conditions using fluorescence spectroscopy in combination with UV-vis absorption and circular dichroism (CD) spectroscopy. Analysis of fluorescence quenching data of HSA by these compounds at different temperatures using Stern-Volmer and Lineweaver-Burk methods revealed the formation of a ground state indolone-HSA complex with binding affinities of the order 10(4) M(-1). The thermodynamic parameters ΔG, ΔH, and ΔS, calculated at different temperatures, indicated that the binding reaction was endothermic and hydrophobic interactions play a major role in this association. The conformational changes of HSA were investigated qualitatively using synchronous fluorescence and quantitatively using CD. Site marker competitive experiments showed that the binding process took place primarily at site I (subdomain IIA) of HSA. The number of binding sites and the apparent binding constants were also studied in the presence of different ions.     

Alpha-phenyl-N-tert-butyl nitrone (PBN) derivatives: synthesis and protective action against microvascular damages induced by ischemia/reperfusion

Nitrones 4-7, structurally related to PBN (1), were prepared by reaction of the corresponding aromatic aldehydes with N-tert-butyl hydroxylamine. The protective effects of these nitrones against microvascular damages in ischemia/reperfusion in the 'hamster cheek pouch' assay were studied and 1, as well as 4a, 4b, and 7 (derived from piperonal, O-benzyl vanillin, and furfural, respectively), showed to be more active than shark cartilage or alpha-tocopherol. No correlation was found between the protective effect of these nitrones and their logP (partition coefficient) or their capacity to trap (*)OH and (*)CH(3) radicals.     

The Burden and Determinants of Non Communicable Diseases Risk Factors in Nepal: Findings from a Nationwide STEPS Survey

Background

World Health Organization (WHO) estimates for deaths attributed to Non Communicable Diseases (NCDs) in Nepal have risen from 51% in 2010 to 60% in 2014. This study assessed the distribution and determinants of NCD risk factors among the Nepalese adult population.

Methods and Findings

A nationally representative cross-sectional survey was conducted from Jan to June 2013 on the prevalence of NCD risk factors using the WHO NCD STEPS instrument. A multistage cluster sampling method was used to randomly select the 4,200 respondents. The adjusted prevalence ratio (APR) was used to assess the determinants of NCD risk factors using a Poisson regression model. The prevalence of current smoking (last 30 days) was 19% (95%CI:16.6-20.6), and harmful alcohol consumption (≥60 g of pure alcohol for men and ≥40 g of pure alcohol for women on an average day) was 2% (95%CI:1.4-2.9). Almost all (99%, 95%CI:98.3-99.3) of the respondents consumed less than five servings of fruits and vegetables combined on an average day and 3% (95%CI:2.7-4.3) had low physical activity. Around 21% (95%CI:19.3-23.7) were overweight or obese (BMI≥25). The prevalence of raised blood pressure (SBP≥140 mm of Hg or DBP≥90 mm of Hg) and raised blood glucose (fasting blood glucose ≥126 mg/dl), including those on medication were 26% (95%CI:23.6-28.0) and 4% (95%CI:2.9-4.5) respectively. Almost one quarter of respondents, 23% (95%CI:20.5-24.9), had raised total cholesterol (total cholesterol ≥190 mg/dl or under current medication for raised cholesterol). he study revealed a lower prevalence of smoking among women than men (APR:0.30; 95%CI:0.25-0.36), and in those who had higher education levels compared to those with no formal education (APR:0.39; 95%CI:0.26-0.58). Harmful alcohol use was also lower in women than men (APR:0.26; 95%CI:0.14-0.48), and in Terai residents compared to hill residents (APR:0.16; 95%CI:0.07-0.36). Physical inactivity was lower among women than men (APR:0.55; 95%CI:0.38-0.80), however women were significantly more overweight and obese (APR:1.19; 95%CI:1.02-1.39). Being overweight or obese was significantly less prevalent in mountain residents than in hill residents (APR:0.41; 95%CI:0.21-0.80), and in rural compared to urban residents (APR:1.39; 95%CI:1.15-1.67). Lower prevalence of raised blood pressure was observed among women than men (APR:0.69; 95%CI: 0.60-0.80). Higher prevalence of raised blood glucose was observed among urban residents compared to rural residents (APR:2.05; 95%CI:1.29-3.25). A higher prevalence of raised total cholesterol was observed among the respondents having higher education levels compared to those respondents having no formal education (APR:1.76; 95%CI:1.35-2.28).

Conclusion

The prevalence of low fruit and vegetable consumption, overweight and obesity, raised blood pressure and raised total cholesterol is markedly high among the Nepalese population, with variation by demographic and ecological factors and urbanization. Prevention, treatment and control of NCDs and their risk factors in Nepal is an emerging public health problem in the country, and targeted interventions with a multi-sectoral approach need to be urgently implemented.     

Neuroprotection against ischemic brain injury conferred by a novel nitrate ester

Nitrates exhibit a selectivity of action in different tissue types not fully recognized: in particular, the neuromodulatory and cardiovascular properties can be dissociated. A novel nitrate showed relatively weak systemic effects, but in the middle cerebral artery occlusion rat model of focal ischemia, reduced the cerebral infarct by 60-70% when administered 4 h after the onset of ischemia.     

Relationship between plant species richness and biomass in an arid sub-alpine grassland of the central Himalayas,Nepal

The hump-shaped relationship between plant species richness and biomass is commonly observed at fine scale for herbaceous vegetation in temperate climates. This relationship predicts that herbaceous species richness is highest at an intermediate level of biomass that corresponds to moderate competition or disturbance. However, this relationship has not previously been investigated in high arid sub-alpine mountain grasslands. We tested the humped-back prediction in the arid Trans-Himalayan mountain grassland with a seasonal grazing system. The study area is located in the bottom of a U-shaped valley, in the Manang district (3500 m a.s.l.). We sampled two hundred plots (1m × 1m) in two different types of pastures: common pasture and old field, which both have similar grazing practices. There was a significant unimodal relationship between species richness and biomass only in the common pasture, and when the two sites were analyzed together. The species turnover is estimated by DCA in standard deviation unit. The turnover was lower in the old field than in the common pasture. The unimodal relationship between plant species richness and biomass did not disappear after accounting for unknown environmental gradients expressed as DCA (detrended correspondence analysis) axes and spatial variables. The species richness is highest at 120 ± 40 g/m². The results indicate that a hump-shaped relationship is also found in arid Trans-Himalayan grasslands.     

The spinal basis of opioid tolerance and physical dependence: Involvement of calcitonin gene-related peptide, substance P, and arachidonic acid-derived metabolites

Chronic opioid use in the management of pain is limited by development of analgesic tolerance and physical dependence. The mechanisms underlying tolerance-dependence are not entirely clear, however, recent evidence suggests that spinal adaptations leading to increased activity of sensory neuropeptides (calcitonin gene-related peptide (CGRP), substance P) and their downstream signaling messengers derived from metabolism of arachidonic acid: prostaglandins (PG), lipoxygenase (LOX) metabolites, and endocannabinoids, plays an important role in this phenomenon. In this communication we review the evidence implicating these factors in the induction and expression of opioid tolerance and physical dependence at the spinal level.     

Variation in plant species richness of different life forms along a subtropical elevation gradient in the Himalayas, east Nepal

Aim To explore the variation in species richness along a subtropical elevation gradient, and evaluate how climatic variables explain the richness of the different life forms such as trees, shrubs, climbers, herbs and ferns. Location The study was made in a subtropical to warm temperate region in the south‐eastern part of Nepal, between 100 and 1500 m above sea level (a.s.l.). Methods The number of species was counted in six plots (50 × 20 m) in each of the 15 100 m elevation bands covering the main physiognomic structures along an imaginary transect. Each species recorded was assigned to a life form. Potential evapotranspiration (PET, i.e. energy), mean annual rainfall (MAR), and their ratio (MI = moisture index) were evaluated as explanatory variables by means of generalized linear models (GLM). Each variable was tested individually, and in addition MAR and PET were used to test the water‐energy dynamics model for each life form. Results The richness of herbaceous species, including herbaceous climbers, was unrelated to any of the climate variables. PET was strongly negatively correlated with elevation, and the following relationships were found between increasing PET and richness: (i) shrubs, trees and total species (sum of all life forms) showed unimodal responses (ii) ferns decreased monotonically, and (iii) woody climbers increased monotonically. Richness of all woody groups increased monotonically with MAR and MI. The water‐energy dynamics model explained 63% of the variation in shrubs, 67% for trees and 70% for woody species combined. Main conclusions For the various herbaceous life forms (forbs, grasses, and herbaceous climbers) we found no significant statistical trends, whereas for woody life forms (trees, shrubs, and woody climbers) significant relationships were found with climate. E.M. O’Brien's macro‐scale model based on water‐energy dynamics was found to explain woody species richness at a finer scale along this elevational‐climatic gradient.