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In this study, a pre-mixing process was applied to assist a high-energy ball milling (HEBM) process to fabricate high-strength aluminium (Al) matrix composites reinforced with carbon nanotubes (CNTs) by powder metallurgy. Effects of initial state on the dispersion quality of CNTs in composites and resultant mechanical properties were investigated using electron microscopy and tensile testing, respectively. Results showed that after pre-mixing, raw CNT agglomerations became flattened CNT clusters, and evolved into individually dispersed CNT fragments on flaky Al powder surface after HEBM for 12 h. However, CNT clusters remained in the same HEBM process without pre-mixing. Both individual CNTs and CNT clusters were observed inside cold-welded Al particles with a prolonged milling time of 24 h. By applying pre-mixing, the reinforcing effect in CNT/Al composites increased by more than 100%. The distinct evolution processes of CNT dispersion during HEBM with different initial states have been discussed. [ABSTRACT FROM PUBLISHER]

When polycrystalline metals and their alloys are used at high temperature, creep deformation leads to changes in their internal state. The change in internal state manifests itself in many ways, but the two ways that concern us in this review are (i) the creation of internal stress arising from the strain incompatibility between grains and/or the formation of cell/sub-grain structures and (ii) a change in the material resistance. This review aims to provide a clear separation of these two concepts by exploring the origin of each term and how it is associated with the creep deformation mechanism. Experimental techniques used to measure the internal stress and internal resistance over different length-scales are critically reviewed. It is demonstrated that the interpretation of the measured values requires knowledge of the dominant creep deformation mechanism. Finally, the concluding comments provide a summary of the key messages delivered in this review and highlight the challenges that remain to be addressed. [ABSTRACT FROM AUTHOR]

Graphite powder is the most widely used source of carbon in making powder metallurgy components. In this study, the graphite powder was replaced by the nanoscale carbon black powder. Compared to graphite powder, the carbon black powder provides more uniform distribution, higher apparent density, and faster flow rate for the Fe–0·8%C powder mixture. After sintering, the homogenisation of carbon, microstructure, and hardness are all similar between the two carbon powders. But a higher amount of spring back during ejection and thus lower green density was attained by using carbon black powders. Nonetheless, the compacts using carbon black powder had higher amounts of shrinkage, which compensated for the spring back effect during sintering, thus giving the same density as the graphite powder. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy was used to observe the microstructures of a cork wood. It showed that the wood consists of countless rectangular and honeycomb wood cells. The wall of each wood cell connects with adjacent wood cells at the middle of the cell wall. More careful observation showed that the walls of the wood cells are a kind of fibre reinforced biocomposite consisting of crystalline cellulose fibre layers and hydrocarbonated polymer matrix. The crystalline cellulose fibres in different fibre layers possess different directions, which compose a kind of fibre helicoidal microstructure. In the microstructure, the helicoidal angle is very large. The maximum pullout force of the fibre helicoidal microstructure, which is closely related to the fracture toughness of the wood, was theoretically and experimentally investigated and compared with that of the fibre parallel microstructure. It showed that the maximum pullout force of the fibre helicoidal microstructure is markedly greater than that of the fibre parallel microstructure and that the larger the helicoidal angle, the more the maximum pullout force will increase compared with that of the parallel microstructure. [ABSTRACT FROM AUTHOR]

There has been a surge of interest in polymer–clay nanocomposites over the past decade. This review surveys these new materials with emphasis on the debate surrounding interaction mechanisms and the behaviour of intercalated polymer in clay galleries. Swelling properties, high cation exchange capacities, high aspect ratio and large surface area give smectite clays the new role of high performance filler for thermoplastic or thermosetting polymers for the creation of intercalated or exfoliated nanocomposites. These nanocomposites can be prepared by three routes: in situ polymerisation, solution methods, or melt processing. Modification of either clay or polymer can change the type of polymer–clay composite. X-ray diffraction and transmission electron microscopy are often employed as the main characterisation techniques to establish the state of the clay. A very low volume fraction of clay significantly improves the mechanical and barrier properties of the pristine polymer, which makes these nanocomposites very promising materials. [ABSTRACT FROM AUTHOR]

The compound Ti3SiC2 is a promising reinforcement for copper, but at a high volume content of Ti3SiC2, densification of Cu/Ti3SiC2 composites becomes difficult. To improve the densification behaviour and microstructure of Cu/Ti3SiC2 composites, Ti3SiC2 particulates were coated with a layer of copper by an electroless plating method before being incorporated into the copper matrix. Results demonstrated that, compared with uncoated Ti3SiC2 reinforced copper, copper coated Ti3SiC2 reinforced composites exhibit both high density and a homogeneous distribution of Ti3SiC2 within the copper matrix. The precoated layer of copper prevents direct contact and agglomeration of Ti3SiC2 particulates. Owing to the improved density and microstructure, the mechanical properties of Cu/Ti3SiC2 composites are also enhanced. Mechanical property investigation revealed that a significant strengthening effect is observed for Cu/Ti3SiC2 composites at both room and high temperatures. [ABSTRACT FROM AUTHOR]

Background Selective dorsal rhizotomy (SDR) is a surgical procedure for treating spasticity in ambulant children with cerebral palsy (CP). However, controversies remain regarding indications, techniques and outcomes. Current evidence summary Because SDR is an irreversible procedure, careful patient selection, a multi-disciplinary approach in assessment and management and division of the appropriate proportion of dorsal rootlets are felt to be paramount for maximizing safety. Reliable evidence exists that SDR consistently reduces spasticity, in a predictable manner and to a substantial degree. However, functional improvements are small in the short-term with long-term benefits difficult to assess. Future outlook There is a need for high-quality studies utilizing long-term functional outcomes and well-matched control groups. Collaborative, multicentre efforts are required to further define the role of SDR as part of the management paradigm in maximizing physical function in spastic CP. [ABSTRACT FROM AUTHOR]

A higher prevalence of depression in systemic lupus erythematosus (SLE) patients has been reported, though the mechanism underlying this phenomenon remains unclear. The present study was conducted to explore whether the polymorphism and methylation status of the serotonin transporter gene (5HTT) promoter region (PR-5HTT) contribute to depression in SLE patients from both genetic and epigenetic perspectives. In this study, 96 SLE patients and 96 healthy controls (HCs) were recruited. Depression levels of all subjects were evaluated using the Hamilton Depression Rating Scale (HDRS). The serotonin transporter-linked polymorphism (5HTTLPR) and the DNA methylation status of PR-5HTT were detected in peripheral lymphocytes of SLE patients and HCs. The differences in 5HTTLPR and DNA methylation of PR-5HTT between SLEs and HCs were compared. In SLE patients, the frequencies of short allele (S) and SS genotype of 5HTTLPR were higher in depressive SLE (SLE-D) patients than in non-depressive SLE (SLE-ND) patients. The mean HDRS score of SS homozygote patients was higher than that of patients with SL/LL genotypes. Conversely, PR-5HTT was hypomethylated in HCs as well as SLE patients. There was no difference in the methylation status between HCs and SLEs. Thus, the functional expression of PR-5HTT may be primarily regulated by gene polymorphism and not by DNA methylation. The risk allele of 5HTTLPR appears to be a major contributor to depression in SLE patients. [ABSTRACT FROM AUTHOR]

Background: Tuberculosis (TB) can produce positive signals during ¹⁸F-fluorodeoxyglucose positron emission/computed tomography (FDG PET/CT) scanning. Until now, there has been no better method than clinical assessment to evaluate the therapeutic response of non-respiratory TB (NRTB). Purpose: To retrospectively assess the ability of FDG PET/CT to evaluate the response to anti-TB treatment in patients with NRTB. Material and Methods: Three patients with multi-site NRTB underwent repeat PET/CT scans during anti-TB treatment. Changes in maximal standard uptake value (SUVmax) of the TB lesions on PET/CT images were analyzed between two scans. Initial PET/CT scans were performed before the start of anti-TB treatment, and later scans were performed after completion of the treatment. Results: Patient 1, a 63-year-old female, and patient 2, a 50-year-old male, were diagnosed as multi-site NRTB by biopsy. Patient 3, a 37-year-old male was diagnosed clinically. These patients demonstrated multiple FDG-avid lesions in whole body on initial PET/CT images. The highest SUVmax of patient 1, 2, and 3 were 13.6, 17.7, and 13.9 separately. After completion of the treatment, all positive signals of patient 1, 2, and 3 decreased to undetectable value on repeated PET/CT scans with intervals of 318 days, 258 days, and 182 days separately. Conclusion: FDG PET/CT scan may be useful for monitoring responses to anti-TB treatment in patients with NRTB. [ABSTRACT FROM AUTHOR]

In the analysis of wind-induced response of single-layer reticulated shell structures, it is found that there are some higher modes which maybe contribute significantly to the vibration. Unfortunately, these higher modes are often ignored when the traditional mode superposition methods are adopted for wind-induced response analyzing, due to the consideration of calculation efficiency. Although some more efficient methods have been put forward, they seem too complex to engineers. From the viewpoint of practice, it is expected to find these contribution-significant modes directly by some easy- understanding criterions. To solve this problem, a Ritz-POD method is introduced firstly, which synthesizes the proper orthogonal decomposition (POD) technique and the Ritz- sector direct superposition method. Based on the Ritz-POD method, some preliminary criterions for identifying the contribution-significant modes are proposed, which take account of the vibration-participating ability of each mode and the relationship between the mode shape and the spatial distribution of the fluctuating wind load. [ABSTRACT FROM AUTHOR]

In this study, we developed a serum and urine metabolomic method based on gas chromatography-mass spectrometry (GC-MS) combination with biomedical results to evaluate the effect of vitamin E treatment on methomyl poisoning rats. The rats were divided into three groups: the control group, methomyl poisoning group, and vitamin E treatment group. Partial least squares discriminate analysis (PLS-DA) showed that methomyl poisoning induced metabolic perturbations. Compared to the control group, based on the urinary metabolomics data, the level of ribitol, L-proline, xylitol, hydrocinnamic acid, 11-cis-octadecenoic acid, octadecanoic acid, and hexadecanoic acid of methomyl poisoning group increased, while the level of 2,3,4-trihydroxybutyric acid, ethanimidic acid, pantothenic acid, and retinoic acid decreased. Vitamin E pretreatment effectively normalized the levels of metabolites in rat urine in vitamin E treatment group. There was no significant difference in rat plasma metabolomic data after acute methomyl poisoning. The results indicate that metabolomic method based on GC-MS may be useful to elucidate the vitamin E treatment for methomyl poisoning. [ABSTRACT FROM AUTHOR]

To improve the efficiency of seismic fragility analysis, this paper analyzes the seismic fragility of isolated continuous girder bridges by adopting the response surface method with random factors. A three-dimensional finite element model is established for a typical RC isolated continuous girder bridge in western China using the finite element analysis software OpenSees. Next, test samples are determined according to experimental design theory by simultaneously accounting for the uncertainty of the structure itself and the earthquake ground motion. The response surface models of the scenario's structural capability can be obtained in terms of the numerical calculation results, after which structural parameter sensitivity analysis is conducted. On this basis, a seismic fragility curve for the major components and structural system can be obtained by the Latin Hypercube method. The analysis shows that concrete's compressive strength is the dominant factor affecting structural capacity in the parameter sensitivity analysis. Use of isolation bearing greatly reduces the possibility of pier damage by contrasting the seismic fragility curve. Briefly, the application of this method not only decreases the workload immensely, providing a new idea for seismic fragility analysis, but also has significant, practical value for the design and optimization of similar isolated bridges. [ABSTRACT FROM AUTHOR]

A case of organophosphate (OP) poisoning was admitted to the emergency room. The patient accepted treatment with pralidoxime (PAM), atropine, and supporting therapy. It was observed that even after 22 h after treatment, 960 mg of atropine was not enough for the patient to be atropinized. However, a 160-mg follow-up treatment of anisodamine was quite enough for atropinization after 4 h. As a case report, more studies are required before any definite conclusion can be reached regarding the use of anisodamine as a potential substitute for high-dose atropine in cases of OP poisoning. [ABSTRACT FROM PUBLISHER]

Full aeroelastic model tests are often carried out to investigate the buffeting responses and the corresponding gust loading factor (GLF) of flexible structures. The geometric model scale for complicated structures may sometimes be excessively large in comparison with the ratio between turbulence integral scales measured in wind tunnel and in real atmospheric environments. This inconsistency in scale modeling leads to severe distortions of turbulence integral scale similarity whose influence manifests itself by modifications in resonant component of buffeting response and in resulting GLF as well, and numerical correction is needed when these testing results are converted to full-scale. This paper presents a correction procedure in terms of correction factors for experimental GLF obtained from full aeroelastic model tests to account for the inconsistency in scale modeling. The correction is simply made on analyzing the prototype in two air flows with different turbulence integral scales, namely the nominal value in the real atmosphere environment and the full-scale value correspondent to aeroelastic model test. The correction procedure is applied to the full aeroelastic model experiments of a transmission line tower with an unusually large geometric scale of 1/40 in order to examine the effect of turbulence integral scale on GLF. An appreciable effect is observed. It is found that the GLF obtained from wind tunnel experiments tends to be conservative for most structures and becomes unsafe for structures with extremely low modal frequencies when disregarding the correction. Correction factors are then derived to accommodate the inconsistency in modeling turbulence integral lengths. As a first generalization, a set of more general correction factors defined in terms of modal damping ratio and frequency ratio, the ratio between modal frequency and the dominant frequency in wind power spectra, are further developed through parametric analysis. The correction factors decrease with the augment of modal damping ratio and frequency ratio. [ABSTRACT FROM AUTHOR]

Abstract: The occurrence of systemic lupus erythematosus (SLE) involves a gene–environment interaction and epigenetic regulations, such as DNA methylation, may play important role in the etiology of SLE. Some neurotransmitters, such as serotonin, can regulate T- and B-cell proliferation via the 5-HT1A receptor and are involved in the pathology of SLE. The abnormal methylation of DNA has been reported in SLE, but there has been no study concerning the serotonin system. This study was conducted to explore the DNA methylation status of the promoter region of HTR1A (PR-HTR1A) and the level of HTR1A mRNA in the peripheral blood lymphocytes (PBLC) of SLE patients and healthy controls (HC). In this study, the DNA methylation status of PR-HTR1A and the level of HTR1A mRNA were detected in the PBLC of SLE patients and HC. The results showed significant hypomethylation of PR-HTR1A in SLE patients compared with HC. The patients also showed a significantly higher HTR1A mRNA level than did the controls. Relatively higher percentage of anti-histone antibodies in methylated SLE patients was found compared with unmethylated patients. Our results support the hypothesis that the hypomethylation of PR-HTR1A and overexpression of HTR1A might contribute to SLE. These results also reveal that epigenetic regulation via the serotonin system may contribute to SLE, and reveal the link between the brain and the immune system. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE) is a complex immune disease. The genetic variation in the PXK gene was found to associate with SLE in Caucasian populations. However, the association of rs6445975 with SLE has not been extensively studied in a Chinese mainland population. A total of 288 SLE patients and 357 controls were recruited. Unlabeled probe-based high-resolution melting analysis (HRMA) was used in genotyping. HRMA with unlabeled probe successfully distinguished all genotypes. Neither genotype nor allele frequencies of SNP rs6445975 showed statistically significant differences between SLE patients and controls. The association of SNP rs6445975 with the diagnostic criteria of SLE was also examined. No obvious association was observed between rs6445975 and the incidence of clinical symptoms. However, the minor allele (G) of rs6445975 was found to significantly associate with increased abnormalities of anti-Smith (p = 0.004, odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.22—3.09), anti-Ro (p = 0.015, OR = 1.69, 95% CI = 1.10—2.58), anti-La (p = 0.008, OR = 1.86, 95% CI = 1.17—2.93) and C3C4 (p = 0.007, OR = 1.79, 95% CI = 1.17—2.74). Polymorphisms of rs6445975 in the PXK gene were associated with autoantibody production, but not disease risk, of systemic lupus erythematosus in a Chinese population. Lupus (2011) 20, 23—27. [ABSTRACT FROM AUTHOR]

A composite double zinc phosphate conversion coating was obtained via forming a hopeite crystal layer on an amorphous phosphate layer on the AZ91D magnesium alloy. The surface morphology, structure and phase composition of the composite coating were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). As a comparison, the single zinc phosphate coating and the bare substrate were also discussed. The phosphate crystal clusters can form on the amorphous layer densely and fine. According to the open circuit potential (OCP) and potentiodynamic polarisation curve tests, the composite phosphate conversion coating on the AZ91D magnesium alloy yielded the best protective effect compared with the single amorphous layer and crystal layer. [ABSTRACT FROM AUTHOR]

Background: Gliosarcomas are rare tumors with mixed glial and mesenchymal components. Many of their radiologic features resemble those of other primary brain malignancies. Purpose: To investigate the magnetic resonance (MR) imaging features of gliosarcomas. Material and Methods: We retrospectively reviewed the MR images, pathology reports, and clinical information of 11 male and four female patients aged 15-71 years to evaluate the location, morphology, enhancement, and other features of their pathologically confirmed gliosarcomas. Results: Apart from one tumor in the right cerebellar hemisphere, all were supratentorial. Two tumors were intraventricular, and four involved the corpus callosum. The tumors were well demarcated, with an inhomogeneous or cystic appearance and moderate-to-extensive surrounding edema. Thick walls with strong rim and ring-like enhancement were observed in 13 (87%). Seven (47%) showed intratumoral paliform enhancement. Conclusion: Gliosarcoma demonstrates certain characteristic MR features, such as supratentorial and peripheral location, well-demarcated, abutting a dural surface, uneven and thick-walled rim-like or ring enhancement, as well as intratumoral strip enhancement. These findings, combined with patient age, can aid the differential diagnosis of gliosarcomas from more common primary brain tumors. [ABSTRACT FROM AUTHOR]

Three-dimensional carbon fibre reinforced nitride composite materials were fabricated by precursor infiltration and pyrolysis using a hybrid precursor. The curing stage of precursor infiltration and pyrolysis was investigated and improved. The densification behaviour, mechanical properties and ablation properties of the composites were studied. The results show that high pressure curing method can be used to fabricate high density composites. With the increase of density from 150 to 165 g cm-3, the flexural strength increases from 1564 to 1923 MPa, and the elastic modulus increases from about 459 to 563 GPa, while the linear ablation rate decreases from 0069 to 0056 mm s-1. The load–displacement curves show that carbon fibres cause efficient reinforcement, and the composites have good toughness. [ABSTRACT FROM AUTHOR]