Dynamic Reconfiguration of Brain Functional Network in Stroke

The brain continually reorganizes its functional network to adapt to post-stroke functional impairments. Previous studies using static modularity analysis have presented global-level behavior patterns of this network reorganization. However, it is far from understood how the brain reconfigures its functional network dynamically following a stroke. This study collected resting-state functional MRI data from 15 stroke patients, with mild (n = 6) and severe (n = 9) two subgroups based on their clinical symptoms. Additionally, 15 age-matched healthy subjects were considered as controls. By applying a multilayer network method, a dynamic modular structure was recognized based on a time-resolved function network. Then dynamic network measurements (recruitment, integration, and flexibility) were calculated to characterize the dynamic reconfiguration of post-stroke brain functional networks, hence, to reveal the neural functional rebuilding process. It was found from this investigation that severe patients tended to have reduced recruitment and increased between-network integration, while mild patients exhibited low network flexibility and less network integration. It is also noted that this severity-dependent alteration in network interaction was not able to be revealed by previous studies using static methods. Clinically, the obtained knowledge of the diverse patterns of dynamic adjustment in brain functional networks observed from the brain signal could help understand the underlying mechanism of the motor, speech, and cognitive functional impairments caused by stroke attacks. The proposed method not only could be used to evaluate patients' current brain status but also has the potential to provide insights into prognosis analysis and prediction

Dynamic Reconfiguration of Brain Functional Network in Stroke

The brain continually reorganizes its functional network to adapt to post-stroke functional impairments. Previous studies using static modularity analysis have presented global-level behavior patterns of this network reorganization. However, it is far from understood how the brain reconfigures its functional network dynamically following a stroke. This study collected resting-state functional MRI data from 15 stroke patients, with mild (n = 6) and severe (n = 9) two subgroups based on their clinical symptoms. Additionally, 15 age-matched healthy subjects were considered as controls. By applying a multilayer network method, a dynamic modular structure was recognized based on a time-resolved function network. Then dynamic network measurements (recruitment, integration, and flexibility) were calculated to characterize the dynamic reconfiguration of post-stroke brain functional networks, hence, to reveal the neural functional rebuilding process. It was found from this investigation that severe patients tended to have reduced recruitment and increased between-network integration, while mild patients exhibited low network flexibility and less network integration. It is also noted that this severity-dependent alteration in network interaction was not able to be revealed by previous studies using static methods. Clinically, the obtained knowledge of the diverse patterns of dynamic adjustment in brain functional networks observed from the brain signal could help understand the underlying mechanism of the motor, speech, and cognitive functional impairments caused by stroke attacks. The proposed method not only could be used to evaluate patients' current brain status but also has the potential to provide insights into prognosis analysis and prediction

Fretting of CoCrMo and Ti6Al4V Alloys in Modular Prostheses

Implantation of a total hip replacements (THR) is an effective intervention in the management of arthritis. Modularity at the taper junction of THR was introduced in order to improve the ease with which the surgeon could modify the length of the taper section and the overall length of the replacement. Cobalt chromium (Co–28Cr–6Mo) and titanium (Ti–6Al–4V) alloys are the most commonly used materials for the device. This study investigates the fretting behaviour of both CoCr–CoCr and CoCr–Ti couplings and analyses their damage mechanisms. A reciprocating tribometer ball on plate fretting contact was instrumented with in situ electrochemistry to characterise the damage inflicted by tribocorrosion on the two couplings. Fretting displacements amplitudes of 10, 25 and 50 mm at an initial contact pressure of 1 GPa were assessed. The results reveal larger metallic volume loss from the CoCr–CoCr alloy compared to the CoCr–Ti alloy, and the open circuit potential indicates a depassivation of the protective oxide layer at displacement amplitudes .25 mm. In conclusion, the damage mechanisms of CoCr–CoCr and CoCr–Ti fretting contacts were identified to be wear and fatigue dominated mechanisms respectively

Dynamic Reconfiguration of Brain Functional Network in Stroke

The brain continually reorganizes its functional network to adapt to post-stroke functional impairments. Previous studies using static modularity analysis have presented global-level behavior patterns of this network reorganization. However, it is far from understood how the brain reconfigures its functional network dynamically following a stroke. This study collected resting-state functional MRI data from 15 stroke patients, with mild (n = 6) and severe (n = 9) two subgroups based on their clinical symptoms. Additionally, 15 age-matched healthy subjects were considered as controls. By applying a multilayer temporal network method, a dynamic modular structure was recognized based on a time-resolved function network. The dynamic network measurements (recruitment, integration, and flexibility) were calculated to characterize the dynamic reconfiguration of post-stroke brain functional networks, hence, revealing the neural functional rebuilding process. It was found from this investigation that severe patients tended to have reduced recruitment and increased between-network integration, while mild patients exhibited low network flexibility and less network integration. It's also noted that previous studies using static methods could not reveal this severity-dependent alteration in network interaction. Clinically, the obtained knowledge of the diverse patterns of dynamic adjustment in brain functional networks observed from the brain neuronal images could help understand the underlying mechanism of the motor, speech, and cognitive functional impairments caused by stroke attacks. The present method not only could be used to evaluate patients' current brain status but also has the potential to provide insights into prognosis analysis and prediction.</p

Realizing optimal hydrogen evolution reaction properties via tuning phosphorous and transition metal interactions

Hydrogen is one of the most attractive renewables for future energy application, therefore it is vital to develop cost-effective and highly-efficient electrocatalysts for the hydrogen evolution reaction (HER) to promote the generation of hydrogen from mild methods. In this work, Co–Mo phosphide nanosheets with the adjustable ratio of Co and Mo were fabricated on carbon cloth by a facile hydrothermal-annealing method. Owing to the unique nanostructures, abundant active surfaces and small resistance were achieved. Excellent electrocatalytic performances are obtained, such as the small overpotential of ∼67.3 mV to realize a current density of 10 mA cm−2 and a Tafel slope of 69.9 mV dec−1. Rapid recovery of the current response under multistep chronoamperometry is realized and excellent stability retained after the CV test for 2000 cycles. The change of electronic states of different elements was carefully studied which suggested the optimal electrochemical performance can be realized by tuning phosphorous and metal interactions

Physical activity and sedentary behaviours among rural adults in suixi, china: a cross-sectional study

Background: Modernisation and urbanisation have led to lifestyle changes and increasing risks for chronic diseases in China. Physical activity and sedentary behaviours among rural populations need to be better understood, as the rural areas are undergoing rapid transitions. This study assessed levels of physical activity and sedentary behaviours of farming and non-farming adults in rural Suixi, described activity differences between farming and non-farming seasons, and examined correlates of leisure-time physical activity (LTPA) and TV viewing.Methods: A random sample of rural adults (n = 287) in Suixi County, Guangdong, China were surveyed in 2009 by trained interviewers. Questionnaires assessed multiple physical activities and sedentary behaviours, and their correlates. Analysis of covariance compared activity patterns across occupations, and multiple logistic regressions assessed correlates of LTPA and TV viewing. Quantitative data analyses were followed by community consultation for validation and interpretation of findings.Results: Activity patterns differed by occupation. Farmers were more active through their work than other occupations, but were less active and more sedentary during the non-farming season than the farming season. Rural adults in Suixi generally had a low level of LTPA and a high level of TV viewing. Marital status, household size, social modelling for LTPA and owning sports equipment were significantly associated with LTPA but not with TV time. Most findings were validated through community consultation.Conclusions: For chronic disease prevention, attention should be paid to the currently decreasing occupational physical activity and increasing sedentary behaviours in rural China. Community and socially-based initiatives provide opportunities to promote LTPA and prevent further increase in sedentary behaviours

Experimental and molecular dynamics simulation study of chemically stable superhydrophobic surfaces

Experimental and molecular dynamics simulation study was used to clarify the hydrophilicity of substrate surfaces and hydrophobicity of as-prepared surfaces at molecular level. First, an easy one-step approach was utilized to construct superhydrophobic surfaces on different substrates such as steel, aluminum, glass, and silicon wafer. The superhydrophobicity of as-prepared surfaces were contributed to the fluorinated compositions and microstructures. A fluorinated surface was constructed as a model of the as-prepared superhydrophobic surface. Molecular dynamics simulations were utilized to elucidate the anti-wetting mechanism of as-prepared fluorinated surfaces on aluminum substrates. Compared with the compact hydrated layer on the aluminum substrate, the hydrated layer on the fluorinated surface were broader with a lower intensity, confirming the lower attractive force between surface and water molecules. The decreased van der Waals interaction with water molecules contributed to the hydrophobicity of the fluorinated surface. While, in an alkaline solution, the electrostatic interaction had a negative impact on hydrophobicity of a fluorinated surface

Using the cre-lox recombination system to assess functional impairment caused by amino acid substitutions in yeast proteins

A method was developed to assess the functional significance of a sequence motif in yeast Upf3p, a protein required for nonsense-mediated mRNA decay (NMD). The motif lies at the edge of the Upf3p-Upf2p interaction domain, but at the same time resembles the canonical leucine-rich nuclear export sequence (NES) found in proteins that bind Crm1p exportin. To test the function of the putative NES, site-directed mutations that cause substitutions of conserved NES-A residues were first selected to identify hypermorphic alleles. Next, a portable Crm1p-binding NES from HIV-1 Rev protein that functions in yeast was fused en masse to the C-terminus of variant Upf3 proteins using loxP sites recognized by bacterial cre-recombinase. Finally, variant Upf3-Rev proteins that were functional in NMD were selected and examined for the types of amino acid substitutions present in NES-A. The mutational analysis revealed that amino acid substitutions in the Upf3 NES impair both nuclear export and the Upf2p-Upf3p interaction, both of which are required for Upf3p to function in NMD. The method described in this report could be modified for the genetic analysis of a variety of portable protein domains

No imminent quantum supremacy by boson sampling

It is predicted that quantum computers will dramatically outperform their conventional counterparts. However, large-scale universal quantum computers are yet to be built. Boson sampling is a rudimentary quantum algorithm tailored to the platform of photons in linear optics, which has sparked interest as a rapid way to demonstrate this quantum supremacy. Photon statistics are governed by intractable matrix functions known as permanents, which suggests that sampling from the distribution obtained by injecting photons into a linear-optical network could be solved more quickly by a photonic experiment than by a classical computer. The contrast between the apparently awesome challenge faced by any classical sampling algorithm and the apparently near-term experimental resources required for a large boson sampling experiment has raised expectations that quantum supremacy by boson sampling is on the horizon. Here we present classical boson sampling algorithms and theoretical analyses of prospects for scaling boson sampling experiments, showing that near-term quantum supremacy via boson sampling is unlikely. While the largest boson sampling experiments reported so far are with 5 photons, our classical algorithm, based on Metropolised independence sampling (MIS), allowed the boson sampling problem to be solved for 30 photons with standard computing hardware. We argue that the impact of experimental photon losses means that demonstrating quantum supremacy by boson sampling would require a step change in technology.Comment: 25 pages, 9 figures. Comments welcom

Assessment of combined scale/corrosion inhibitors - A combined jar test/bubble cell

The formation of calcium carbonate scale and the occurrence of CO corrosion are both widespread phenomena observed within pipework during oil and gas production. The most common form of treatment for both processes is the application of chemical inhibition through corrosion and/or scale inhibitors. Surface scaling of pipework rarely occurs in environments where no corrosion exists, yet techniques used to develop and assess the performance of scale inhibitors tend to focus on assessing and reducing solely bulk/surface scaling, without affording consideration towards corrosion, whilst corrosion inhibitors are frequently evaluated in non-scaling environments. Furthermore, both chemicals tend to be evaluated independently meaning that any potential antagonistic effects between the chemicals can go unrecognised. This paper addresses this very issue by presenting a unique setup and methodology to enable the occurrence of scale and corrosion to be monitored simultaneously in a CO-saturated environment in the presence and absence of combined scale and corrosion inhibitors. The test cell focuses on evaluating four key parameters which are quantified either throughout the duration of the test, or from the implementation of post-test surface analysis techniques. The multiple assessment of (i) bulk scale precipitation, (ii) surface scaling, (iii) general corrosion and (iv) localised corrosion permits a full assessment of the chemical blends propensity to mitigate both scaling and corrosion. Non-inhibited tests were initially conducted at 60 °C to form a baseline for comparison. Four combined scale/corrosion inhibitors were subsequently used at low concentrations in order to understand their mechanisms and highlight any competitive effect which existed in reducing either scale or corrosion. The results demonstrate that the methodology implemented is effective at assessing the efficiency of combined inhibitors in reducing both corrosion and scale in environments where both processes occur simultaneously. The limitations of conducting solely bulk scaling or corrosion tests in non-scaling environments are discussed relative to the results obtained in this work. The results of each individual inhibitor are discussed and markedly different behaviour is observed according to the concentration administered, as well as the particular blend of chemicals applied