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The 'social brain hypothesis' for the evolution of large brains in primates has led to evidence for the coevolution of neocortical size and social group sizes, suggesting that there is a cognitive constraint on group size that depends, in some way, on the volume of neural material available for processing and synthesizing information on social relationships. More recently, work on both human and non-human primates has suggested that social groups are often hierarchically structured. We combine data on human grouping patterns in a comprehensive and systematic study. Using fractal analysis, we identify, with high statistical confidence, a discrete hierarchy of group sizes with a preferred scaling ratio close to three: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3-5, 9-15, 30-45, etc. Such discrete scale invariance could be related to that identified in signatures of herding behaviour in financial markets and might reflect a hierarchical processing of social nearness by human brains.

Background Accumulating evidence have shown that the intestinal microbiota plays an important role in prevention of host obesity and metabolism disorders. Recent studies also demonstrate that early life is the key time for the colonization of intestinal microbes in host. However, there are few studies focusing on possible association between intestinal microbiota in the early life and metabolism in adulthood. Therefore the present study was conducted to examine whether the short term antibiotic and/or probiotic exposure in early life could affect intestinal microbes and their possible long term effects on host metabolism. Results A high-fat diet resulted in glucose and lipid metabolism disorders with higher levels of visceral fat rate, insulin-resistance indices, and leptin. Exposure to ceftriaxone in early life aggravated the negative influences of a high-fat diet on mouse physiology. Orally fed TMC3115 protected mice, especially those who had received treatment throughout the whole study, from damage due to a high-fat diet, such as increases in levels of fasting blood glucose and serum levels of insulin, leptin, and IR indices. Exposure to ceftriaxone during the first 2 weeks of life was linked to dysbiosis of the fecal microbiota with a significant decrease in the species richness and diversity. However, the influence of orally fed ceftriaxone on the fecal microbiota was limited to 12 weeks after the termination of treatment. Of note, at week 12 there were still some differences in the composition of intestinal microbiota between mice provided with high fat diet and antibiotic exposure and those only fed a high fat diet. Conclusions These results indicated that exposure to antibiotics, such as ceftriaxone, in early life may aggravate the negative influences of a high-fat diet on the physiology of the host animal. These results also suggest that the crosstalk between the host and their intestinal microbiota in early life may be more important than that in adulthood, even though the same intestinal microbes are present in adulthood.

The observation of magnetic interaction at the interface between nonmagnetic oxides has attracted much attention in recent years. In this report, we show that the Kondo-like scattering at the SrTiO 3 -based conducting interface is enhanced by increasing the lattice mismatch and growth oxygen pressure P O2 . For the 26-unit-cell LaAlO 3 /SrTiO 3 (LAO/STO) interface with lattice mismatch being 3.0%, the Kondo-like scattering is observed when P O2 is beyond 1 mTorr. By contrast, when the lattice mismatch is reduced to 1.0% at the (La 0.3 Sr 0.7 )(Al 0.65 Ta 0.35 )O 3 /SrTiO 3 (LSAT/STO) interface, the metallic state is always preserved up to P O2 of 100 mTorr. The data from Hall measurement and X-ray absorption near edge structure (XANES) spectroscopy reveal that the larger amount of localized Ti 3+ ions are formed at the LAO/STO interface compared to LSAT/STO. Those localized Ti 3+ ions with unpaired electrons can be spin-polarized to scatter mobile electrons, responsible for the Kondo-like scattering observed at the LAO/STO interface.

Down‐regulation of protein phosphatase 2A (PP2A) is thought to play a critical role in tau hyperphosphorylation in Alzheimer's disease (AD). In vitro phosphorylation of PP2A catalytic subunit at Y307 efficiently inactivates PP2A. A specific antibody against phosphorylated (p) PP2A (Y307) (PP2Ac‐Yp307) was used to investigate possible PP2A down‐regulation by known pathophysiological changes associated with AD, such as Aβ accumulation and oestrogen deficiency. Immunohistochemistry and immunofluorescence confocal microscopy showed an aberrant accumulation of PP2Ac‐Yp307 in neurons that bear pretangles or tangles in the susceptible brain regions, such as the entorhinal cortical cortex and the hippocampus. Experimentally, increased PP2Ac‐Yp307 was observed in mouse N2a neuroblastoma cells that stably express the human amyloid precursor protein with Swedish mutation (APPswe) compared with wild‐type, and in the brains of transgenic APPswe/ presenilin (PS1, A246E) mice, which corresponded to the increased tau phosphorylation. Treating N2a cells with Aβ25–35 mimicked the changes of PP2Ac‐Yp307 and tau phosphorylation in N2a APPswe cells. Knockout of oestrogen receptor (ER) α or ERβ gave similar changes of PP2Ac‐Yp307 level and tau phosphorylation in the mouse brain. Taken together, these findings suggest that increased PP2A phosphorylation (Y307) can be mediated by Aβ deposition or oestrogen deficiency in the AD brain, and consequently compromise dephosphorylation of abnormally hyperphosphorylated tau, and lead to neurofibrillary tangle formation.

Despite extensive studies in the past, deterioration of mechanical properties due to hydrogen environment exposure remains a serious problem for structural materials. More effective improvement of a material’s resilience requires advanced computational methods to elucidate the fundamental mechanisms of the hydrogen effects. To enable accurate molecular dynamics (MD) studies of the hydrogen effects on metals, we have developed a high-fidelity analytical bond-order potential (BOP) for the copper–hydrogen binary system as a representative case. This potential is available through the publically available MD code LAMMPS. The potential parameters are optimized using an iterative process. First, the potential is fitted to static and reactive properties of a variety of elemental and binary configurations including small clusters and bulk lattices (with coordination varying from 1 to 12). Then the potential is put through a series of rigorous MD simulation tests (e.g., vapor deposition and solidification) that involve chaotic initial configurations. It is demonstrated that this Cu–H BOP not only gives structural and property trends close to those seen in experiments and quantum mechanical calculations, but also predicts the correct phase transformations and chemical reactions in direct MD simulations. The correct structural evolution from chaotic initial states strongly verifies the transferability of the potential. A highly transferable potential is the reason that a well-parameterized analytical BOP can enable MD simulations of metal-hydrogen interactions to reach a fidelity level not achieved in the past.

In recent years, China’s ship transportation has shown a rapid growth trend, and the accidents of ships hitting bridge piers are becoming more and more frequent. In view of the frequent occurrence of ships hitting bridge piers, this paper selects closed-cell aluminum foam as the anti-collision material of the piers, and conducts cumulative horizontal impact tests on the closed-cell aluminum foam protected concrete piers. The aim of the experimental tests was to study the influence of the stress stage, thickness and density change of the closed-cel laluminum foam on the impact damage of the concrete piers. The test results show that under the cumulative impact, the close-cell aluminum foam at the yield plateau stage can reduce the damage of the pier; the suitable thickness and density of closed-cell aluminum foam can slow down the development of pier cracks and reduce the impact damage of concrete piers; the densification, excessive thickness and density of closed-cell aluminum foam will increase the impact damage of the bridge pier.

As part of the Tibet Ozone, Aerosol and Radiation (TOAR) project, a micropulse lidar was operated in Naqu (31.5°N, 92.1°E; 4508 m MSL) on the Tibetan Plateau to observe cirrus clouds continuously from 19 July to 26 August 2011. During the experiment, the time coverage of ice clouds only was 15% in the upper troposphere (above 9.5 km MSL). The cirrus top/bottom altitudes (mean values of 15.6/14.7 km) are comparable to those measured previously at tropical sites but relatively higher than those measured at midlatitude sites. The majority of the cloud layers yielded a lidar ratio between 10 and 40 sr, with a mean value of 28 ± 15 sr, characterized by a bimodal frequency distribution. Subvisible, thin, and opaque cirrus formation was observed in 16%, 34%, and 50% of all cirrus cases, respectively. A mean cirrus optical depth of 0.33 was observed over the Tibetan Plateau, slightly higher than those in the subtropics and tropics. With decreasing temperature, the lidar ratio increased slightly, whereas the mean extinction coefficient decreased significantly. The occurrence of clouds is highly correlated with the outgoing longwave radiation and the strong cold perturbations in the upper troposphere. Deep convective activity and Rossby waves are important dynamical processes that control cirrus variations over the Tibetan Plateau, where both anvil cirrus outflowing from convective cumulonimbus clouds and large-scale strong cold perturbations in the upper troposphere should play an important role in cirrus formation.

Accumulation evidence shows that β -amyloid (A β ) is a neurotoxic and accumulation of A β is responsible for the pathology of Alzheimer’s disease (AD). However, it is currently not fully understood what makes A β toxic and accumulated. Previous studies demonstrate that A β is a suitable substrate for glycation, producing one form of the advanced glycation endproducts (AGEs). We speculated that A β -AGE formation may exacerbate the neurotoxicity. To explore whether the A β -AGE is more toxic than the authentic A β and to understand the molecular mechanisms, we synthesized glycated A β by incubating A β with methylglyoxal (MG) in vitro and identified the formation of glycated A β by fluorescence spectrophotometer. Then, we treated the primary hippocampal neurons cultured 8 days in vitro with A β -AGE or A β for 24 h. We observed that glycation exacerbated neurotoxicity of A β with upregulation of receptor for AGE (RAGE) and activation of glycogen synthase kinase-3 (GSK-3), whereas simultaneous application of RAGE antibody or GSK-3 inhibitor reversed the neuronal damages aggravated by glycated A β . Thereafter, we found that A β is also glycated with an age-dependent elevation of AGEs in Tg2576 mice, whereas inhibition of A β -AGE formation by subcutaneously infusion of aminoguanidine for 3 months significantly rescued the early cognitive deficit in mice. Our data reveal for the first time that the glycated A β is more toxic. We propose that the glycated A β with the altered secondary structure may be a more suitable ligand than A β for RAGE and subsequent activation of GSK-3 that can lead to cascade pathologies of AD, therefore glycated A β may be a new therapeutic target for AD.

Purpose The methods of repairing defects in fingers, volar skin of the palm and soft tissue were investigated. Methods From 2010 to the present, we examined 12 cases in which medial plantar skin flaps were used to repair defects in the fingers and palm. According to skin and soft tissue defects in the fingers and palm, a flap was designed using the medial plantar artery as the vessel pedicle. The flap was dissected and isolated between the abductor hallucis and flexor digitorum brevis, and transplanted to the hand. We then observed the skin colour, skin texture and tactile sensitivity of the hand, as well as the shape and function of the foot. Results Follow-up for 3–28 months showed that the flaps survived in all 12 cases, with soft skin, healthy appearance, colour consistent with the palm skin and no pigmentation. The two-point discrimination was 5–7 mm. The donor foot functioned well, and the scar at the donor site was slight and had an aesthetic appearance. Conclusion The free medial plantar flap is an ideal flap for repairing soft tissue defects in the palm.

Low-level features tend to achieve unsatisfactory retrieval results in remote sensing image retrieval community because of the existence of semantic gap. In order to improve retrieval precision, visual attention model is used to extract salient objects from image according to their saliency. Then color and texture features are extracted from salient objects and regarded as feature vectors for image retrieval. Experimental results demonstrate that our method improves retrieval results and obtains higher precision.