Menopause effect on blood Fe and Cu isotope compositions

Iron (δ⁵⁶Fe) and copper (δ⁶⁵Cu) stable isotope compositions in blood of adult human include a sex effect, which still awaits a biological explanation. Here, we investigate the effect of menopause by measuring blood δ⁵⁶Fe and δ⁶⁵Cu values of aging men and women. The results show that, while the Fe and Cu isotope compositions of blood of men are steady throughout their lifetime, postmenopausal women exhibit blood δ⁶⁵Cu values similar to men, and δ⁵⁶Fe values intermediate between men and premenopausal women. The residence time of Cu and Fe in the body likely explains why the blood δ⁶⁵Cu values, but not the δ⁵⁶Fe values, of postmenopausal women resemble that of men. We suggest that the Cu and Fe isotopic fractionation between blood and liver resides in the redox reaction occurring during hepatic solicitation of Fe stores. This reaction affects the Cu speciation, which explains why blood Cu isotope composition is impacted by the cessation of menstruations. Considering that Fe and Cu sex differences are recorded in bones, we believe this work has important implications for their use as a proxy of sex or age at menopause in past populations. Am J Phys Anthropol 153:280–285, 2014. © 2013 Wiley Periodicals, Inc.     

Non‐coding RNA involvement in the pathogenesis of diabetic cardiomyopathy

In recent years, the incidence of diabetes has been increasing rapidly, which seriously endangers human health. Diabetic cardiomyopathy, an important cardiovascular complication of diabetes, is characterized by myocardial fibrosis, ventricular remodelling and cardiac dysfunction. It has been documented that mitochondrial dysfunction, oxidative stress, inflammatory response, autophagy, apoptosis, diabetic microangiopathy and myocardial fibrosis are implicated in the pathogenesis of diabetic cardiomyopathy. With the development of molecular biology technology, accumulating evidence demonstrates that non‐coding RNAs (ncRNAs) are critically involved in the molecular mechanisms of diabetic cardiomyopathy. In this review, we summarize the pathological roles of three types of ncRNAs (microRNA, long ncRNA and circular RNA) in the progression of diabetic cardiomyopathy, which may provide valuable insights into the pathogenesis of diabetic cardiovascular complications.     

Contrasting dynamics of water and mineral nutrients in stems shown by stable isotope tracers and cryo‐SIMS

Lateral exchange of water and nutrients between xylem and surrounding tissues helps to de‐couple uptake from utilization in all parts of a plant. We studied the dynamics of these exchanges, using stable isotope tracers for water (H₂¹⁸O), magnesium (²⁶Mg), potassium (⁴¹K) and calcium (⁴⁴Ca) delivered via a cut stem for various periods to the transpiration stream of bean shoots (Phaseolus vulgaris cv. Fardenlosa Shiny). Tracers were subsequently mapped in stem cross‐sections with cryo‐secondary ion mass spectrometry. The water tracer equilibrated within minutes across the entire cross‐section. In contrast, the nutrient tracers showed a very heterogeneous exchange between xylem vessels and the different stem tissues, even after 4 h. Dynamics of nutrients in the tissues revealed a fast and extensive exchange of nutrients in the xylem parenchyma, with, for example, calcium being completely replaced by tracer in less than 5 min. Dilution of potassium tracer during its 30 s transit in xylem sap through the stem showed that potassium concentration was up‐regulated over many hours, to the extent that some of it was probably supplied by phloem recirculation from the shoot.     

Metal‐Organic Framework‐Derived Non‐Precious Metal Nanocatalysts for Oxygen Reduction Reaction

By virtue of diverse structures and tunable properties, metal‐organic frameworks (MOFs) have presented extensive applications including gas capture, energy storage, and catalysis. Recently, synthesis of MOFs and their derived nanomaterials provide an opportunity to obtain competent oxygen reduction reaction (ORR) electrocatalysts due to their large surface area, controllable composition and pore structure. This review starts with the introduction of MOFs and current challenges of ORR, followed by the discussion of MOF‐based non‐precious metal nanocatalysts (metal‐free and metal/metal oxide‐based carbonaceous materials) and their application in ORR electrocatalysis. Current issues in MOF‐derived ORR catalysts and some corresponding strategies in terms of composition and morphology to enhance their electrocatalytic performance are highlighted. In the last section, a perspective for future development of MOFs and their derivatives as catalysts for ORR is discussed.     

Chronological and Isotopic data support a revision for the timing of cave bear extinction in Mediterranean Europe

Abstract

The Cave Bear, Ursus spelaeus (sensu lato), was one of many megafaunal species that became extinct during the Late Pleistocene in Europe. With new data we revisit the debate about the extinction and paleoecology of this species by presenting new chronometric, isotopic and taphonomic evidence from two Palaeolithic cave bear sites in northeastern Italy: Paina Cave and Trene Cave. Two direct radiocarbon dates on well-preserved collagen have yielded ages around 24,200–23,500 cal yr BP, which make them the latest known representatives of the species in Europe. The carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopic values of bone collagen exhibit values similar to those of older cave bears from Swabian Jura and France, suggesting that the feedings preferences of cave bears remained unchanged until the disappearance of this species in Europe. Several bear remains preserved traces of human modification such as cut marks, which enables a reconstruction of the main steps of fur recovery and the butchering process. The broad range of plant types available and the favorable location of Berici Hills may have played an important role in the range expansion of cave bears and their interaction with the Paleolithic hunters settled the same area.     

Overcoming Space‐Charge Effect for Efficient Thick‐Film Non‐Fullerene Organic Solar Cells

Organic solar cells (OSCs) containing non‐fullerene acceptors have realized high power conversion efficiency (PCE) up to 14%. However, most of these high‐performance non‐fullerene OSCs have been reported with optimal active layer thickness of about 100 nm, mainly due to the low electron mobility (≈10^?4–10^?5 cm² V^?1 s^?1) of non‐fullerene acceptors, which are not suitable for roll‐to‐roll large‐scale processing. In this work, an efficient non‐fullerene OSC based on poly[(5,6‐difluoro‐2,1,3‐benzothiadiazol‐4,7‐diyl)‐alt‐(3,3′″‐di(2‐octyldodecyl)‐2,2′;5′,2″;5″,2′″‐quaterthiophen‐5,5′′′‐diyl)] (PffBT4T‐2OD):EH‐IDTBR (consists of electron‐rich indaceno[1,2‐b:5,6‐b′]dithiophene as the central unit and an electron‐deficient 5,6‐benzo[c][1,2,5]thiadiazole unit flanked with rhodanine as the peripheral group) with thickness‐independent PCE (maintaining a PCE of 9.1% with an active layer thickness of 300 nm) is presented by optimizing device architectures to overcome the space‐charge effects. Optical modeling reveals that most of the incident light is absorbed near the transparent electrode side in thick‐film devices. The transport distance of electrons with lower mobility will therefore be shortened when using inverted device architecture, in which most of the excitons are generated close to the cathode side and therefore substantially reduces the accumulation of electrons in the device. As a result, an efficient thick‐film non‐fullerene OSC is realized. These results provide important guidelines for the development of more efficient thick‐film non‐fullerene OSCs.     

Non‐genetic diversity modulates population performance

Biological functions are typically performed by groups of cells that express predominantly the same genes, yet display a continuum of phenotypes. While it is known how one genotype can generate such non‐genetic diversity, it remains unclear how different phenotypes contribute to the performance of biological function at the population level. We developed a microfluidic device to simultaneously measure the phenotype and chemotactic performance of tens of thousands of individual, freely swimming Escherichia coli as they climbed a gradient of attractant. We discovered that spatial structure spontaneously emerged from initially well‐mixed wild‐type populations due to non‐genetic diversity. By manipulating the expression of key chemotaxis proteins, we established a causal relationship between protein expression, non‐genetic diversity, and performance that was theoretically predicted. This approach generated a complete phenotype‐to‐performance map, in which we found a nonlinear regime. We used this map to demonstrate how changing the shape of a phenotypic distribution can have as large of an effect on collective performance as changing the mean phenotype, suggesting that selection could act on both during the process of adaptation.     

Recent Progress on Stability Enhancement for Cathode in Rechargeable Non‐Aqueous Lithium‐Oxygen Battery

The pressing demand on the electronic vehicles with long driving range on a single charge has necessitated the development of next‐generation high‐energy‐density batteries. Non‐aqueous Li‐O₂ batteries have received rapidly growing attention due to their higher theoretical energy densities compared to those of state‐of‐the‐art Li‐ion batteries.To make them practical for commercial applications, many critical issues must be overcome, including low round‐trip efficiency and poor cycling stability, which are intimately connected to the problems resulting from cathode degradation during cycling. Encouragingly, during the past years, much effort has been devoted to enhancing the stability of the cathode using a variety of strategies and these have effectively surmounted the challenges derived from cathode deteriorations,thus endowing Li‐O₂ batteries with significantly improved electrochemical performances. Here, a brief overview of the general development of Li‐O₂ battery is presented. Then, critical issues relevant to the cathode instability are discussed and remarkable achievements in enhancing the cathode stability are highlighted. Finally, perspectives towards the development of next generation highly stable cathode are also discussed.     

Roux‐en‐Y Gastric Bypass Improves Liver Histology in Patients with Non‐Alcoholic Fatty Liver Disease

Objectives: Non‐alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease in the United States and is prevalent in morbidly obese patients. While weight loss and treatment of risk factors are recommended, the reported effects of bariatric surgery on NAFLD are mixed. Research Methods and Procedures: We examined liver histology at the time of Roux‐en‐Y gastric bypass surgery and at elective incisional hernia repair after weight loss for 16 patients at one center. Slides were read by one pathologist, blinded to clinical data, using the Brunt criteria. Clinical and laboratory data were extracted from chart review. Alcohol use was ascertained by two interviews. Results: At baseline, the mean age was 44 years, 50% were women, 88% were white, and the mean BMI was 51 kg/m². None had significant alcohol use. On initial biopsy, all patients showed steatosis, 94% had inflammation, 88% had ballooning degeneration, 88% had perisinusoidal fibrosis, and 81% had portal fibrosis. The mean time between the two biopsies was 305 ± 131 (SD) days. The mean weight loss was 118 ± 29 lb. Steatosis improved in 15 of 16 patients, with resolution in 13. Twelve of 15 patients with inflammation at baseline showed improvement, and 12 of 14 showed less ballooning. Six of 14 patients with perisinusoidal fibrosis and 6 of 13 with portal fibrosis showed improvement. No patient had worsening of steatosis, inflammation, ballooning, or fibrosis. Discussion: Our study shows improvement in all of the histological features of NAFLD after Roux‐en‐Y gastric bypass surgery—induced weight loss, despite significant histopathology at baseline and substantial weight loss.     

Constructing High‐Performance Organic Photovoltaics via Emerging Non‐Fullerene Acceptors and Tandem‐Junction Structure

In consideration of the unique advantages of new non‐fullerene acceptors and the tandem‐junction structure, organic photovoltaics (OPVs) based on them are very promising. Studies related to this emerging area began in 2016 with achieved power conversion efficiencies (PCEs) of 8–10%, which have now been boosted to 17%. In this essay, the construction of high‐performance OPVs is discussed, with a focus on combining the advantages of new non‐fullerene acceptors and the tandem‐junction structure. In order to achieve higher PCEs, methods to enable high short‐circuit current density, open‐circuit voltage, and fill factor are discussed. In addition, the stability and reproducibility of high‐efficiency OPVs are also addressed. Herein, it is forecast that the new non‐fullerene acceptors‐based tandem‐junction OPVs will become the next big wave in the field and achieve high PCEs over 20% in the near future. Some promising research directions on this emerging hot topic are proposed which may further push the field into the 25% high efficiency era and considerably advance the technology beyond laboratory research.     

Photographic identification of individuals of a free‐ranging,small terrestrial vertebrate

Recognition of individuals within an animal population is central to a range of estimates about population structure and dynamics. However, traditional methods of distinguishing individuals, by some form of physical marking, often rely on capture and handling which may affect aspects of normal behavior. Photographic identification has been used as a less‐invasive alternative, but limitations in both manual and computer‐automated recognition of individuals are particularly problematic for smaller taxa (<500 g). In this study, we explored the use of photographic identification for individuals of a free‐ranging, small terrestrial reptile using (a) independent observers, and (b) automated matching with the Interactive Individual Identification System (I³S Pattern) computer algorithm. We tested the technique on individuals of an Australian skink in the Egernia group, Slater's skink Liopholis slateri, whose natural history and varied scale markings make it a potentially suitable candidate for photo‐identification. From ‘photographic captures’ of skink head profiles, we designed a multi‐choice key based on alternate character states and tested the abilities of observers — with or without experience in wildlife survey — to identify individuals using categorized test photos. We also used the I³S Pattern algorithm to match the same set of test photos against a database of 30 individuals. Experienced observers identified a significantly higher proportion of photos correctly (74%) than those with no experience (63%) while the I³S software correctly matched 67% as the first ranked match and 83% of images in the top five ranks. This study is one of the first to investigate photo identification with a free‐ranging small vertebrate. The method demonstrated here has the potential to be applied to the developing field of camera‐traps for wildlife survey and thus a wide range of survey and monitoring applications.     

Non‐hemolytic enterotoxin of Bacillus cereus induces apoptosis in Vero cells

Bacillus cereus is an opportunistic pathogen that often causes foodborne infectious diseases and food poisoning. Non‐hemolytic enterotoxin (Nhe) is the major toxin found in almost all enteropathogenic B. cereus and B. thuringiensis isolates. However, little is known about the cellular response after Nhe triggered pore formation on cell membrane. Here, we demonstrate that Nhe induced cell cycle arrest at G₀/G₁ phase and provoked apoptosis in Vero cells, most likely associated with mitogen‐activated protein kinase (MAPK) and death receptor pathways. The influx of extracellular calcium ions and increased level of reactive oxygen species in cytoplasm were sensed by apoptosis signal‐regulating kinase 1 (ASK1) and p38 MAPK. Extrinsic death receptor Fas could also promote the activation of p38 MAPK. Subsequently, ASK1 and p38 MAPK triggered downstream caspase‐8 and 3 to initiate apoptosis. Our results clearly demonstrate that ASK1, and Fas‐p38 MAPK‐mediated caspase‐8 dependent pathways are involved in apoptotic cell death provoked by the pore‐forming enterotoxin Nhe.     

Non‐enzymatic glycolysis and pentose phosphate pathway‐like reactions in a plausible Archean ocean

The reaction sequences of central metabolism, glycolysis and the pentose phosphate pathway provide essential precursors for nucleic acids, amino acids and lipids. However, their evolutionary origins are not yet understood. Here, we provide evidence that their structure could have been fundamentally shaped by the general chemical environments in earth's earliest oceans. We reconstructed potential scenarios for oceans of the prebiotic Archean based on the composition of early sediments. We report that the resultant reaction milieu catalyses the interconversion of metabolites that in modern organisms constitute glycolysis and the pentose phosphate pathway. The 29 observed reactions include the formation and/or interconversion of glucose, pyruvate, the nucleic acid precursor ribose‐5‐phosphate and the amino acid precursor erythrose‐4‐phosphate, antedating reactions sequences similar to that used by the metabolic pathways. Moreover, the Archean ocean mimetic increased the stability of the phosphorylated intermediates and accelerated the rate of intermediate reactions and pyruvate production. The catalytic capacity of the reconstructed ocean milieu was attributable to its metal content. The reactions were particularly sensitive to ferrous iron Fe(II), which is understood to have had high concentrations in the Archean oceans. These observations reveal that reaction sequences that constitute central carbon metabolism could have been constrained by the iron‐rich oceanic environment of the early Archean. The origin of metabolism could thus date back to the prebiotic world.