New thermodynamic entropy calculation based approach towards quantifying the impact of eutrophication on water environment

© 2017 Although the eutrophication phenomenon has been studied for a long time, there are still no quantifiable parameters available for a comprehensive assessment of its impacts on the water environment. As contamination alters the thermodynamic equilibrium of a water system to a state of imbalance, a novel method was proposed, in this study, for its quantitative evaluation. Based on thermodynamic analyses of the algal growth process, the proposed method targeted, both theoretically and experimentally, the typical algae species encountered in the water environment. By calculating the molar enthalpy of algae biomass production, the heat energy dissipated in the photosynthetic process was firstly evaluated. The associated entropy production (ΔS) in the aquatic system could be then obtained. For six algae strains of distinct molecular formulae, the heat energy consumed for the production of a unit algal biomass was found to proportionate to the mass of nitrogen (N) or phosphorus (P) uptake through photosynthesis. A proportionality relationship between ΔS and the algal biomass with a coefficient circa 44 kJ/g was obtained. By the principle of energy conservation, the heat energy consumed in the process of algae biomass production is stored in the algal biomass. Furthermore, by measuring the heat of combustion of mature algae of Microcystis flos-aquae, Anabaena flos-aquae, and Chlorella vulgaris, the proportionality relationships between the heat energy and the N and P contents were validated experimentally at 90% and 85% confidence levels, respectively. As the discharge of excess N and P from domestic wastewater treatment plants is usually the main cause of eutrophication, the proposed impact assessment approach estimates that for a receiving water body, the ΔS due to a unit mass of N and P discharge is 268.9 kJ/K and 1870.1 kJ/K, respectively. Consequently, P discharge control would be more important for environmental water protection

Characterization of preconcentrated domestic wastewater toward efficient bioenergy recovery: Applying size fractionation, chemical composition and biomethane potential assay.

Domestic wastewater (DWW) can be preconcentrated to facilitate energy recovery via anaerobic digestion (AD), following the concept of "carbon capture-anaerobic conversion-bioenergy utilization." Herein, real DWW and preconcentrated domestic wastewater (PDWW) were both subject to particle size fractionation (0.45-2000 μm). DWW is a type of low-strength wastewater (average COD of 440.26 mg/L), wherein 60% of the COD is attributed to the substances with particle size greater than 0.45 μm. Proteins, polysaccharides, and lipids are the major DWW components. PDWW with a high COD concentration of 2125.89 ± 273.71 mg/L was obtained by the dynamic membrane filtration (DMF) process. PDWW shows larger proportions of settleable and suspended fractions, and accounted for 63.4% and 33.8% of the particle size distribution, and 52.4% and 32.2% of the COD, respectively. The acceptable biomethane potential of 262.52 ± 11.86 mL CH4/g COD of PDWW indicates bioenergy recovery is feasible based on DWW preconcentration and AD

Synthesis, structure, and magnetism in the ferromagnet La_{3}MnAs_{5}: Well-separated spin chains coupled via itinerant electrons

In this work, we systematically report the synthesis, structure, and magnetism of a compound of filled anti-Mn3Si5 type La3MnAs5. It crystallizes in a hexagonal structure with the space group of P63/mcm (193). The structure consists of face-sharing MnAs6 octahedral chains along the c axis, which are well separated by a large distance of 8.9913 Å, demonstrating a strong one-dimensional (1D) structural character. Physical property measurements indicate that La3MnAs5 is a ferromagnetic metal with TC ∼ 112 K. Due to the short-range intrachain spin coupling, the susceptibility deviates from the Curie-Weiss behavior in a wide temperature window and the magnetic entropy corresponding to the ferromagnetic transition is significantly lower than that expected from the fully saturated state. The magnetic critical behavior studies show that La3MnAs5 can be described by the three-dimensional Heisenberg model. The orbital hybridization between the 1D MnAs6 chain and intermediate La atom near the Fermi level reveals that the itinerant electrons play a key role in transmitting spin interaction among the MnAs6 spin chains. Our results indicate that La3MnAs5 is a rare ferromagnetic metal with well-separated spin chains, which provides a good opportunity to study the mechanism of interchain spin coupling via itinerant electrons

Knowledge and attitude on maternal health care among rural-to-urban migrant women in Shanghai, China

<p>Abstract</p> <p>Background</p> <p>In China, with the urbanization, women migrated from rural to big cities presented much higher maternal mortality rates than local residents. Health knowledge is one of the key factors enabling women to be aware of their rights and health status in order to seek appropriate health services. This study aims to assess the knowledge and attitude on maternal health care and the contributing factors to being knowledgeable among rural-to-urban migrant women in Shanghai.</p> <p>Methods</p> <p>A cross-sectional study was conducted in a district center hospital in Shanghai where migrants gathered. Totally 475 rural-to-urban migrant pregnant women were interviewed and completed the self-administered questionnaire after obtaining informed consent.</p> <p>Results</p> <p>The mean score of knowledge on maternal health care was 8.28 out of 12. However, only 36.6% women had attended the required 5 antenatal checks, and 58.3% of the subjects thought financial constrains being the main reason for not attending antenatal care. It was found that higher level of education (OR = 3.3, 95%CI: 1.8–3.8), husbands' Shanghai residence (OR = 4.0, 95%CI: 1.3–12.1) and better family income (OR = 3.3, 95%CI: 1.4–8.2) were associated with better knowledge.</p> <p>Conclusions</p> <p>Rural-to-urban migrant women's unawareness of maternal health service, together with their vulnerable living status, influences their utilization of maternal health care. Tailored maternal health education and accessible services are in demands for this population.</p

Catalyst preparation for CMOS-compatible silicon nanowire synthesis

Metallic contamination was key to the discovery of semiconductor nanowires, but today it stands in the way of their adoption by the semiconductor industry. This is because many of the metallic catalysts required for nanowire growth are not compatible with standard CMOS (complementary metal oxide semiconductor) fabrication processes. Nanowire synthesis with those metals which are CMOS compatible, such as aluminium and copper, necessitate temperatures higher than 450 C, which is the maximum temperature allowed in CMOS processing. Here, we demonstrate that the synthesis temperature of silicon nanowires using copper based catalysts is limited by catalyst preparation. We show that the appropriate catalyst can be produced by chemical means at temperatures as low as 400 C. This is achieved by oxidizing the catalyst precursor, contradicting the accepted wisdom that oxygen prevents metal-catalyzed nanowire growth. By simultaneously solving material compatibility and temperature issues, this catalyst synthesis could represent an important step towards real-world applications of semiconductor nanowires.Comment: Supplementary video can be downloaded on Nature Nanotechnology websit

The P2 Receptor Antagonist PPADS Supports Recovery from Experimental Stroke In Vivo

BACKGROUND: After ischemia of the CNS, extracellular adenosine 5'-triphosphate (ATP) can reach high concentrations due to cell damage and subsequent increase of membrane permeability. ATP may cause cellular degeneration and death, mediated by P2X and P2Y receptors. METHODOLOGY/PRINCIPAL FINDINGS: The effects of inhibition of P2 receptors by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) on electrophysiological, functional and morphological alterations in an ischemia model with permanent middle cerebral artery occlusion (MCAO) were investigated up to day 28. Spontaneously hypertensive rats received PPADS or vehicle intracerebroventricularly 15 minutes prior MCAO for up to 7 days. The functional recovery monitored by qEEG was improved by PPADS indicated by an accelerated recovery of ischemia-induced qEEG changes in the delta and alpha frequency bands along with a faster and sustained recovery of motor impairments. Whereas the functional improvements by PPADS were persistent at day 28, the infarct volume measured by magnetic resonance imaging and the amount of TUNEL-positive cells were significantly reduced by PPADS only until day 7. Further, by immunohistochemistry and confocal laser scanning microscopy, we identified both neurons and astrocytes as TUNEL-positive after MCAO. CONCLUSION: The persistent beneficial effect of PPADS on the functional parameters without differences in the late (day 28) infarct size and apoptosis suggests that the early inhibition of P2 receptors might be favourable for the maintenance or early reconstruction of neuronal connectivity in the periinfarct area after ischemic incidents

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency–Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field