Search

This study primarily aims to investigate the influence of concrete interface properties on the anisotropic behavior of three-dimensional (3D) printed concrete (3DPC). A numerical model employing the traction-separation law was developed to capture the detailed behavior of concrete interfaces in 3DPC. To simulate the interfaces, zero-thickness cohesive elements were implemented. Experimental results indicate that horizontal shear deformation at the interfaces between printed layers reduces the compressive strength of 3D printed specimens. Additionally, the flexural strength of the 3D printed sample is mainly influenced by the tensile strength at the midspan. Specimens loaded in the Y- and Z-directions show relatively lower compressive strength but significantly higher flexural strength. Numerical analysis reveals that the number of interlayers and interstrips and shear properties contribute to changes in anisotropy when specimens are subjected to compression and flexure. Recommendations and influencing factors for improving the simulation modeling of 3DPC with anisotropic behavior have been proposed for future studies. [ABSTRACT FROM AUTHOR]

With mandelic acid (MA) as the chiral core, two series of non-symmetric liquid crystal (LC) dimers have been synthesised by changing the rigidity of the side-arms, namely the DBM-nC2B series and the DBBM-nC2B series. In the DBM-nC2B series, one side-arm is the same, while the length of the flexible tail of the other side-arm increases from 0 to 4. The same is true of the DBBM-nC2B series. Chemical structures and LC properties of the two series LC dimers were characterised by FT-IR, 1H NMR, 13C NMR, DSC, TGA and POM. The results show that the DBM-nC2B series LC dimers display the nematic phase (N), and the DBBM-nC2B series LC dimers exhibit the chiral nematic phase (N*). It shows that the side-arm should have sufficient rigidity for MA to induce the N* phase. In the same series, when the length of the flexible tails of the side-arm increases from 0 to 4, it does not change the mesophase, while it has some effect on the melting temperature (Tm), the clearing temperature (TN(*)I), and mesophase range of the dimers. The molecular length-width ratio (l/w) and dipole moment (μ) were used to explain the variation of Tm and (TN(*)I) of LC dimer. [ABSTRACT FROM AUTHOR]

In this paper, we have synthesised cholesteryl 4-allyloxybenzoate (MB), crosslinking agent dodecane-1,12-diyl bis(undec-10-enoate) (MG), and A'BGF series liquid crystalline elastomer (LCE) films which take polymethylhydrosiloxane (A') as the backbone, MB as the cholesteric liquid crystal (LC) monomer, and MG and bis-vinyl silicone oil (MF) with different reactivities as cross-linking agent for exploring the effect of the change of MF content on the properties of the elastomeric films. The experimental results show that the synthesised MB, MG, and the LCE films are all consistent with the molecular design; MB is an enantiotropic cholesteric LC. The synthesised LCE films are cholesteric LCs, have certain selective reflection characteristic, higher thermal stability, and their Tg decreased down to 3.9°C as MF increasing. During the heating and cooling, the liquid crystalline properties of the LCE films have a good reversibility. Among the synthesised LCE films, A'BGF-2 has stretching radio of 264.8% at room temperature, with the best elastic properties. By adjusting the ratio of MF, the content of small-molecule MB remained in the films can be changed, which will affect the optical properties and elasticity of the LCE films. The experiments provide a method for the preparation of highly elastic side chain LCE film. [ABSTRACT FROM AUTHOR]

Two series of symmetric liquid crystal dimers, namely 1F and 3F, have been synthesised by varying the length of the flexible odd spacer. The melting temperatures and clear points of the 3F series are higher than those of the 1F series. The 1F series only exhibits nematic phase, while the 3F series displays both smectic A and nematic phases. As the length of the flexible spacer increases, the dominance of the smectic phase becomes more pronounced. This phenomenon may be attributed to the combined effect by the polar end group CF3 and the long flexible spacer on the molecular conformation. [ABSTRACT FROM AUTHOR]

A series of liquid crystal elastomer films (the PBC series) have been synthesized by grafting liquid crystal (LC) monomer 4-allyloxybenzoic acid cholesteryl ester (MB) and crosslinking agent [1,1'-biphenyl]-4,4'-diyl bis(undec-10-enoate) (MC) onto polymethylhydrosiloxane catalyzed by hexachloroplatinic acid at 60 °C. The PBC series are cholesteric liquid crystal elastomers (LCEs). The glass transition temperatures (Tg) of the PBC series are between 23-33 °C, and the LC range is above 200 °C. The temperatures of 5% weight loss of the PBC series are above 300 °C, which shows good thermal stability. The PBC series display good orientation. PB3C3 shows a good ability of shape recovery above Tg. [ABSTRACT FROM AUTHOR]

Corrosion of longitudinal reinforcement and stirrup in reinforced and prestressed concrete beams is very common for structures and infrastructures, which is one of the main reasons for the decrease in stiffness and durability of structure. In order to evaluate the influence of corrosion of different types of stirrups on the bearing capacity of the prestressed concrete beam, the method of using electricity to accelerate corrosion was adopted. Load experiment on 4 corroded prestressed concrete beams with different corrosion rates and different stirrup types was carried out. In this paper, reduced scale model beams were designed based on the 5 × 50 m simple-continuous box girder of the Donghai Bridge. The results show that for prestressed concrete beams with different corrosion rates and stirrup types, the load-deflection curve can be divided into an elastic stage and a plastic stage. The corrosion of longitudinal bars and stirrups will reduce the flexural capacity, but the overall decline is not obvious. When the corrosion rate is 10%, the bearing capacity of the ordinary stirrup specimen decreases by 6.1%; epoxy-coated stirrup specimen decreases by 4.9%; stainless stirrup specimen has nearly no change. The influence of different types of stirrups on cracking load, deflection, and bond-slip behavior is discussed. [ABSTRACT FROM AUTHOR]

Tumour‐associated macrophage (TAM) polarization is associated with hepatocellular carcinoma but the molecular mechanism of this polarization is still unknown. Peripheral blood mononuclear cells were induced to differentiate into M0, M1 and M2 macrophages and TAMs. TAMs were transfected with pcDNA3.1‐GAS5, pcDNA3.1‐NC, si‐GAS5, si‐PTEN or si‐Ctrl. A human liver cancer cell line (SMCC‐7721) was incubated with the modified TAM supernatant. Quantitative real‐time PCR and Western blot were performed to detect gene and protein expression. The cell proliferation and invasion properties of the SMCC‐7721 cells were detected by MTT and Transwell assays. GAS5 is up‐regulated in M1 macrophages and down‐regulated in M2 macrophages and TAMs. GAS5 overexpression promoted M1‐like polarization of TAMs and inhibited M2‐like polarization of TAMs. Moreover, GAS5 promoted the expression of PTEN in TAMs. PTEN‐silenced TAM supernatant treatment promoted cell proliferative and invasive properties of the SMCC‐7721 cells and diminished the effect of GAS5‐overexpressed TAM supernatant on the cell proliferation and invasion by SMCC‐7721 cells. Our results demostrared that GAS5 overexpression inhibited M2‐like polarization of TAMs by enhancing PTEN expression, thereby inhibiting cell proliferation and invasion by SMCC‐7721 cells. Thus, our results suggest that GAS5 may be a new therapeutic target for HCC treatment. [ABSTRACT FROM AUTHOR]

Invasive species are a major and growing threat to China's native freshwater biodiversity. They have caused species extinctions, biodiversity loss, and environmental changes. Mrigal carp (Cirrhinus mrigala), one of the most widespread and invasive of freshwater fish species, now occurs in major rivers throughout southern China. We report the current (to 2017) distribution of mrigal carp throughout southern China, and experiments with temperature, water quality and food availability, that assess possible impacts of this species on populations of native mud carp (C. molitorella)". In the wild, the mud carp to mrigal carp weight ratio was 1:1.65. Mrigal carp were a dominant species in some rivers of southern China, such as Liuxi River, Zengjiang River and the Zhaoqing section of Xijiang River. Manipulative experiments reveal mrigal carp to be more tolerant of colder temperature, more eutrophic conditions, and lower dissolved oxygen levels than mud carp. In food-limited experiments, mrigal carp displayed no direct aggression towards mud carp, but they did snatch food from them, and excluded them from eating. Mud carp growth was curtailed in the presence of mrigal carp in food-limited treatments, with a growth rate 2.71%, only 17.02% of that in treatments where carp were fed to satiation. In satiation treatments, mrigal carp also grew up to 2.21 times faster than mud carp. Our results indicate that mrigal carp will outcompete mud carp for resources and habitat, and that both its distribution and population will increase in the future. [ABSTRACT FROM AUTHOR]

A new method for the synthesis of vinyl trifluoromethyl compounds from α, β‐unsaturated carboxylic acids and CF3SO2Na has been developed. This electrochemical decarboxylative trifluoro‐methylation was found to be highly stereoselective and afforded products in good yields with wide substrate scope under metal‐free and external chemical oxidant‐free conditions. [ABSTRACT FROM AUTHOR]

Directionally distributed steel fibre-reinforced concrete (SFRC) cannot be widely applied due to the limitations of current construction technology, which hinders research on its mechanical properties. With the development of new construction technologies, such as self-compacting concrete or 3D printing, directionally distributed SFRC has found new developmental opportunities. This study tested, compared, and analysed the basic mechanical properties of ordinary concrete, randomly distributed SFRC, and directionally distributed SFRC. The differences between the damage patterns parallel and perpendicular to the direction of the steel fibres were evaluated in directionally distributed SFRC. When the fibre volume fraction is high and the compression is applied perpendicular to the fibre direction, as the loading increases, the transverse deformation of the specimen is constrained by the fibres. When the compression is applied parallel to the fibre direction, the fibre cannot effectively constrain the transverse deformation of the specimens. When the volume fraction of directionally distributed steel fibres was 1.6%, the elastic modulus of the directionally distributed steel fibres was 39% higher than that of ordinary concrete. Comparison of the experimental values of the elastic modulus with those estimated by existing calculation methods revealed that a modification of the current calculation theories may be required to calculate the changes in the elastic modulus of directionally distributed SFRC with a high volume fraction of steel fibres. [ABSTRACT FROM AUTHOR]

The fibre utilization efficiency of directionally distributed fibre-reinforced concrete is better than that of randomly distributed fibre. However, controlling the fibre direction is difficult, which limits its applications. In this paper, a method in which fibres were artificially directed was used to simulate the feasibility of orienting fibres during 3D concrete printing. Based on artificially directed steel fibre-reinforced concrete specimens, the orientation characteristics of directional fibre-reinforced concrete specimens were studied. The differences between the gravity and the boundary effects in ordinary fibre-reinforced concrete and artificially directed fibre-reinforced concrete were compared. The average orientation coefficient in randomly distributed fibre-reinforced concrete was 0.59, whereas this value in directionally distributed fibre-reinforced concrete was over 0.9. This result demonstrated the feasibility of manually orienting the fibres in steel fibre-reinforced concrete in layer-by-layer casting. [ABSTRACT FROM AUTHOR]

UDP-glucuronosyltransferases (UGTs), the most important enzymes in body detoxification and homeostasis maintaining, govern the glucuronidation reaction of various endogenous and environmental carcinogens. The metabolic function of UGTs can be severely influenced by hepatocellular carcinoma (HCC), the fifth prevalent and third malignant cancer worldwide. Particularly in China, HBV-positive HCC account for approximately 80% of HCC patients. But rare papers addressed the alteration on the metabolism of UGTs specific substrates, translational and transcriptional activity of UGTs in HBV-positive HCC patients. In present study, we choose the main UGT isoforms, UGT1As, UGT1A1, UGT1A9, UGT1A4 and UGT2B7, to determine the alterations of metabolic activity, protein and gene expression of UGTs in HBV-positive HCC. The corresponding specific substrates such as genistein, SN-38, tamoxifen, propofol and zidovudine were utilized respectively in UGTs metabolic activity determination. Furthermore, the plausible mechanism responsible for UGTs alterations was addressed by analyzing the protein and gene expressions in tumor and the adjacent normal tissues in HBV-positive HCC. The results revealed that in the tumor human liver microsomes (HLMs), either Vmax (maximum reaction rate, Rmax for UGT1A1) or the clearance rates (Vmax/Km, Clint) of UGT1A, UGT1A1, UGT1A4, UGT1A9 and UGT2B7 were significant lower than those of in the adjacent normal HLMs. Subsequently, the relative protein and gene expressions of these isoforms were notably decreased in most of tumor tissues comparing with the adjacent normal tissues. More interestingly, in tumor tissues, the metabolic activity reduction ratio of each UGT isoform was closely related to its protein reduction ratio, indicating that decreasing protein level would contribute to the reduced metabolic function of UGTs in HBV-positive HCC. In summary, our study firstly determined the alteration of UGT function in HBV-positive HCC patients, which would provide an important insight for toxicity or efficacy determination of chemotherapeutic drugs, and even bring a new strategy for clinical regimen in the health cares for the relative patients. [ABSTRACT FROM AUTHOR]

Recent studies have examined the influence on patterns of human genetic variation of a variety of cultural practices. In India, centuries-old marriage customs have introduced extensive social structuring into the contemporary population, potentially with significant consequences for genetic variation. Social stratification in India is evident as social classes that are defined by endogamous groups known as castes. Within a caste, there exist endogamous groups known as gols (marriage circles), each of which comprises a small number of exogamous gotra (lineages). Thus, while consanguinity is strictly avoided and some randomness in mate selection occurs within the gol, gene flow is limited with groups outside the gol. Gujarati Patels practice this form of 'exogamic endogamy.' We have analyzed genetic variation in one such group of Gujarati Patels, the Chha Gaam Patels (CGP), who comprise individuals from six villages. Population structure analysis of 1,200 autosomal loci offers support for the existence of distinctive multilocus genotypes in the CGP with respect to both non-Gujaratis and other Gujaratis, and indicates that CGP individuals are genetically very similar. Analysis of Y-chromosomal and mitochondrial haplotypes provides support for both patrilocal and patrilineal practices within the gol, and a low-level of female gene flow into the gol. Our study illustrates how the practice of gol endogamy has introduced fine-scale genetic structure into the population of India, and contributes more generally to an understanding of the way in which marriage practices affect patterns of genetic variation. Am J PhyAnthropol 2012. © Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: Mitochondrial disorders are a large and genetically heterogeneous group of disorders posing a significant diagnostic challenge. Only approximately 10–20% of patients have identifiable alterations in their mitochondrial DNA (mtDNA). The remaining ~80–90% of affected patients likely harbor mutations in nuclear genes, most of which are still poorly characterized, and therefore not amenable to efficient screening using currently available molecular methods. Here we present a patient, who has been followed since birth after presenting with neonatal hyperammonemia, lactic acidosis, Reye-like syndrome episodes, and ventricular tachyarrhythmia. Initial biochemical work-up revealed hyperalaninemia, normal plasma glutamine, mild orotic aciduria and significant amounts of urinary 3-methylglutaconic (3-MGC) and 3-methylglutaric (3-MGA) acids. Muscle biopsy demonstrated the presence of ragged-red fibers and non-specific structural abnormalities of mitochondria. The activities of respiratory chain enzymes (complexes I–IV) showed no deficiency. Mutational analysis of the entire mitochondrial genome did not reveal deleterious point mutations or large deletions. Long-term follow-up was significant for a later-onset hypertrophic cardiomyopathy, muscle weakness, and exercise intolerance. Although she had frequent episodes of Reye-like episodes in infancy and early childhood, mostly triggered by illnesses, these symptoms improved significantly with the onset of puberty. In the light of recent reports linking cases of type IV 3-methylglutaconic aciduria (3-MGCA) and hypertrophic cardiomyopathy to mutations in TMEM70, we proceeded with sequencing analysis of this gene. We identified one previously reported splice site mutation, c.317-2A>G and a novel mutation c.494G>A (p.G165D) in an evolutionarily conserved region predicted to be deleterious. This variant was not identified in 100 chromosomes of healthy control subjects and 200 chromosomes of patients with cardiomyopathies. Western blotting using a polyclonal antibody against ATP5J, subunit F6 of ATP synthase, on patient''s skin fibroblasts showed undetectable amount of the ATP5J protein. In comparison to the previously reported cases, we note that our patient had normal growth parameters and cognitive development, absence of structural heart and urinary tract defects, no dysmorphic features, improvement of symptoms with age, and persistence of hypertrophic cardiomyopathy. [Copyright &y& Elsevier]

Abstract: Thymidine kinase 2 (TK2), encoded by the TK2 gene on chromosome 16q22, is one of the deoxyribonucleoside kinases responsible for the maintenance of mitochondrial deoxyribonucleotide pools. Defects in TK2 mainly cause a myopathic form of the mitochondrial DNA depletion syndrome (MDDS). Currently, only point mutations and small insertions and deletions have been reported in TK2 gene; gross rearrangements of TK2 gene and possible hepatic involvement in patients with TK2 mutations have not been described. We report a non-consanguineous Jordanian family with three deceased siblings due to mtDNA depletion. Sequence analysis of the father detected a heterozygous c.761T>A (p.I254N) mutation in his TK2 gene; however, point mutations in the mother were not detected. Subsequent gene dosage analysis using oligonucleotide array CGH identified an intragenic approximately 5.8-kb deletion encompassing the 5′UTR to intron 2 of her TK2 gene. Sequence analysis confirmed that the deletion spans c.1–495 to c.283–2899 of the TK2 gene (nucleotide 65,136,256–65,142,086 of chromosome 16). Analysis of liver and muscle specimens from one of the deceased infants in this family revealed compound heterozygosity for the paternal point mutation and maternal intragenic deletion. In addition, a significant reduction of the mtDNA content in liver and muscle was detected (10% and 20% of age- and tissue-matched controls, respectively). Prenatal diagnosis was performed in the third pregnancy. The fetus was found to carry both the point mutation and the deletion. This child died 6months after birth due to myopathy. A serum specimen demonstrated elevated liver transaminases in two of the infants from whom results were available. This report expands the mutation spectrum associated with TK2 deficiency. While the myopathic form of MDDS appears to be the main phenotype of TK2 mutations, liver dysfunction may also be a part of the mitochondrial depletion syndrome caused by TK2 gene defects. [Copyright &y& Elsevier]

The gene products involved in mammalian mitochondrial DNA (mtDNA) maintenance and organization remain largely unknown. We report here a novel mitochondrial protein, Twinkle, with structural similarity to phage T7 gene 4 primase/helicase and other hexameric ring helicases. Twinkle colocalizes with mtDNA in mitochondrial nucleoids. Screening of the gene encoding Twinkle in individuals with autosomal dominant progressive external ophthalmoplegia (adPEO), associated with multiple mtDNA deletions, identified 11 different coding-region mutations co-segregating with the disorder in 12 adPEO pedigrees of various ethnic origins. The mutations cluster in a region of the protein proposed to be involved in subunit interactions. The function of Twinkle is inferred to be critical for lifetime maintenance of human mtDNA integrity. [ABSTRACT FROM AUTHOR]