An Experimental Study on Effect of Steel Corrosion on the Bond–Slip Performance of Reinforced Concrete

This paper studied the effects of reinforcement corrosion on bond performance between rebar and concrete. Tests were carried out to evaluate the degradation of bond between reinforcing steel and concrete for different corrosion levels of reinforcing steel. A series of 20 specimens of different concrete strength with various reinforcing steel corrosion levels were designed and manufactured. Each specimen was casted as a 200-mm concrete cube, and a steel rebar was centrally embedded with two stirrups around it. The steel rebar were corroded using an electrochemical accelerated corrosion technique. The corrosion crack opening width and length were recorded after the corrosion process. Then, monolithic pull-out loading tests were carried out on the specimens. The effects of reinforcement corrosion on crack opening, maximum bond stress, and energy dissipation were discussed in detail. It was found that reinforcement corrosion has non-negligible effects on bond performance of reinforcing bar in concrete

Long-Term Efficacy and Safety of Human Umbilical Cord Mesenchymal Stromal Cells in Rotenone-Induced Hemiparkinsonian Rats

Several studies have shown functional improvements, neuroprotective, and neuroregenerative effects after mesenchymal stem cells transplantation to parkinsonian animal models. However, questions remain about the safety, feasibility, and long-term efficacy of this approach. In this study, we investigated migration, therapeutic, tumorigenesis, and epileptogenic effects of human umbilical cord mesenchymal stromal cells (HUMSCs) 1 year after transplantation into rotenone-induced hemiparkinsonian rats. Our data indicated that DiI-labeled HUMSCs migrated in the lesioned hemisphere, from corpus striatum (CPu) to substantia nigra. By integrating with host cells and differentiating into NSE, GFAP, Nestin, and tyrosine hydroxylase-positive cells, HUMSCs prevented 48.4% dopamine neurons from degeneration and 56.9% dopamine terminals from loss, both correlating with improvement of apomorphine-induced rotations. The CD50 and CD97 value of pentylenetetrazol and semiquantitative immunohistochemical analysis of proliferating cell nuclear antigen (PCNA), β-catenin, C-myc, and NF-κB expression showed no significant difference between HUMSCs transplanted and untransplanted groups, whereas the expressions of Bcl-2 and P53 in the grafted CPu were upregulated by 281% and 200% compared to ungrafted CPu. The results of this long-term study suggest that HUMSCs transplantation, 1 of the most potential treatments for Parkinson's disease, is an effective and safe approach

Identifying barriers to the care of the rheumatoid hand in China: comparing attitudes of rheumatologists and hand surgeons

AimIn China, hand surgeons treat fewer rheumatoid arthritis (RA) patients compared to other countries. We investigated whether physician and surgeon knowledge, attitudes and practices regarding RA hand deformities reflect current evidence and may contribute to the low utilization of surgery.MethodWe surveyed hand surgeons and rheumatologists at three tertiary hospitals in Beijing, China. Questionnaires were developed from literature and expert review to assess their knowledge, attitudes and practice patterns related to rheumatoid hand surgery.ResultsThirtyâ five hand surgeons and 59 rheumatologists completed the survey. Roughly oneâ third felt that the rheumatologists and hand surgeons agree on how to manage RA hand deformities. Oneâ fifth of rheumatologists and 29% of hand surgeons believed that drug therapy can correct hand deformities, which contradicts current evidence. Likewise, 30% and 14%, respectively, recommended surgery for earlyâ stage hand sequelae that do not meet current indications for surgery. Over 80% of surgeons and rheumatologists had no exposure to the other specialty during training and felt their training on the treatment of rheumatoid hand deformities was inadequate.ConclusionAlthough we found similar interspeciality disagreement in China as is seen in the United States, there appears to be less interaction through training and consultations. Our results also indicate potential deficits in training and unawareness of evidence and indications for rheumatoid hand surgery. These findings help to explain why surgery for rheumatoid hand deformities is rare in China; doctors have fewer opportunities to collaborate across specialties and may not be able to select appropriate candidates for surgery.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147075/1/apl12971.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147075/2/apl12971_am.pd

Acupuncture for Lateral Epicondylitis: A Systematic Review

Objective. This systematic review aimed to assess the effectiveness and safety of acupuncture for lateral epicondylitis (LE). Methods. Seven databases and the WHO International Clinical Trials Registry Platform Search Portal were searched to identify relevant studies. The data were extracted and assessed by two independent authors, and Review Manager Software (V.5.3) was used for data synthesis with effect estimate presented as standard mean difference (SMD) and mean difference (MD) with a 95% confidence interval. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to assess the level of evidence. Results. Four RCTs with 309 participants were included with poor methodological quality. Participants who received acupuncture and acupuncture plus moxibustion with material insulation were likely to have an improvement in elbow functional status and/or myodynamia. The overall quality rated by GRADE was from very low to low. Two studies reported that the needle pain would be the main reason for the dropout. Conclusion. For the small number of included studies with poor methodological quality, no firm conclusion can be drawn regarding the effect of acupuncture of elbow functional status and myodynamia for LE. This trial is registered with CRD42015016199

Thermal Properties of Carbon Nanotube–Copper Composites for Thermal Management Applications

Carbon nanotube–copper (CNT/Cu) composites have been successfully synthesized by means of a novel particles-compositing process followed by spark plasma sintering (SPS) technique. The thermal conductivity of the composites was measured by a laser flash technique and theoretical analyzed using an effective medium approach. The experimental results showed that the thermal conductivity unusually decreased after the incorporation of CNTs. Theoretical analyses revealed that the interfacial thermal resistance between the CNTs and the Cu matrix plays a crucial role in determining the thermal conductivity of bulk composites, and only small interfacial thermal resistance can induce a significant degradation in thermal conductivity for CNT/Cu composites. The influence of sintering condition on the thermal conductivity depended on the combined effects of multiple factors, i.e. porosity, CNTs distribution and CNT kinks or twists. The composites sintered at 600°C for 5 min under 50 MPa showed the maximum thermal conductivity. CNT/Cu composites are considered to be a promising material for thermal management applications

Stereotaxical Infusion of Rotenone: A Reliable Rodent Model for Parkinson's Disease

A clinically-related animal model of Parkinson's disease (PD) may enable the elucidation of the etiology of the disease and assist the development of medications. However, none of the current neurotoxin-based models recapitulates the main clinical features of the disease or the pathological hallmarks, such as dopamine (DA) neuron specificity of degeneration and Lewy body formation, which limits the use of these models in PD research. To overcome these limitations, we developed a rat model by stereotaxically (ST) infusing small doses of the mitochondrial complex-I inhibitor, rotenone, into two brain sites: the right ventral tegmental area and the substantia nigra. Four weeks after ST rotenone administration, tyrosine hydroxylase (TH) immunoreactivity in the infusion side decreased by 43.7%, in contrast to a 75.8% decrease observed in rats treated systemically with rotenone (SYS). The rotenone infusion also reduced the DA content, the glutathione and superoxide dismutase activities, and induced alpha-synuclein expression, when compared to the contralateral side. This ST model displays neither peripheral toxicity or mortality and has a high success rate. This rotenone-based ST model thus recapitulates the slow and specific loss of DA neurons and better mimics the clinical features of idiopathic PD, representing a reliable and more clinically-related model for PD research

Enhanced performance on CO2 adsorption and release induced by structural transition that occurred in TBAB center dot 26H(2)O hydrates

The applications of ionic clathrate hydrates have greatly improved the efficiency and the conditions required for hydrate-based CO2 capture, but high energy input for hydrate growth and complicated treatment of hydrate slurry still hinder their commercial use. Here we chose TBAB center dot 26H(2)O hydrate particles to adsorb CO2 molecules instead of TBAB solutions below 2 MPa and release them at ambient pressure. Results showed that the TBAB center dot 26H(2)O hydrate could adsorb CO2 without induction time and enhance the gas storage capacity by structural transition, especially under high pressure. By using in situ Raman, CO2 molecules were found to fill the empty cages in TBAB center dot 26H(2)O hydrate first, the formed nCOZTBAB center dot 26H(2)O hydrate then converted to nCOZTBAB center dot 38H(2)O and TBAB center dot 2(1)/3H2O hydrates at 2 MPa. Macroscopic measurements revealed that around 20 volume of CO2 in standard state could be adsorbed by 1 volume of TBAB center dot 26H(2)O hydrate sample at 1 MPa, but this volume ratio could reach 67 v/v at 2 MPa where structural change was thought to take place. The pressurized CO2 trapped in hydrate phase was assumed to destroy the structure of TBAB center dot 26H(2)O hydrate easily, and force the water molecules to form a structure that more compatible with CO2 molecules. This may explain why nCOZTBAB center dot 26H(2)O hydrates barely grow from TBAB solutions when pressurized CO2 is injected. In the CO2 release process, the nCOZTBAB center dot 38H(2)O and TBAB center dot 2(1)/3H2O hydrates quickly transformed back to nCO(2)center dot TBAB center dot 26H(2)O hydrates and 60-80% of the captured CO2 could be released. Combing with their excellent gas selectivity, TBAB center dot 26H(2)O hydrate particles would be an ideal material for hydrate-based CO2 capture

Microscopic measurements on the decomposition behaviour of methane hydrates formed in natural sands

In this work, the decomposition behaviour of methane hydrate in porous media was investigated microscopically using powder X-ray diffraction, cryogenic scanning electron microscopy and in situ Raman spectroscopy. The effect of grain sizes on the decomposition of methane hydrate was measured. The results showed that bulk hydrates could exist stably at 223 K and atmospheric pressure because of the self-preservation effect. However, hydrate formed in sands was relatively easier to decompose because it had a higher equilibrium pressure compared with bulk hydrate at the same temperature. In this case, there would be a higher decomposition driving force. Interestingly, the complete decomposition time for hydrate formed in sands did not decrease with the decrease in particle size. The shortest decomposition time was observed for the sands with the particle size range of 38-55 m, which was less than 30 minutes. Moreover methane hydrate was found to decompose faster in the porous medium containing 3.5 wt% NaCl, which suggested that there was almost no self-preservation effect. In situ Raman measurements showed that the integrated intensity ratio of methane in large and small cages (A(L)/A(S)) did not change during the decomposition process, suggesting that the methane hydrate crystal units decomposed as an entity in sands. This study provided important data as a basis for drilling fluid technology in hydrate mining