Search

Magnetic fluids are the suspensions composed of magnetic nanoparticles, surfactants, and non-magnetic carrier liquids. Magnetic fluids are widely used in various fields, especially in sealing, because of their excellent features, including rapid magnetic response, flexible flow ability, tunable magneto-viscous effect, and reliable self-repairing capability. Here, we provide an in-depth, comprehensive insight into the theoretical analyses and diverse applications of magnetic fluids in sealing from three categories: static sealing, rotary sealing, and reciprocating sealing. We summarize the magnetic fluid sealing mechanisms and the development of magnetic fluid seals from 1960s to the present, particularly focusing on the recent progress of magnetic fluid seals. Although magnetic fluid sealing technology has been commercialized and industrialized, many difficulties still exist in its applications. At the end of the review, the present challenges and future prospects in the progress of magnetic fluid seals are also outlined. [ABSTRACT FROM AUTHOR]

N6-methyladenosine (m6A) methyltransferase-like 3 (METTL3) has been confirmed to be involved in multiple myeloma (MM) progression, and basic leucine zipper and W2 domains 2 (BZW2) is considered to be a regulator for MM development. However, whether METTL3 mediates MM progression by regulating BZW2 remains unclear. The messenger RNA (mRNA) and protein levels of METTL3 and BZW2 in MM specimens and cells were determined using quantitative real-time PCR and western blot analysis. Cell proliferation and apoptosis were assessed by cell counting kit 8 assay, 5-ethynyl-2′-deoxyuridine assay, colony formation assay, and flow cytometry. Methylated RNA immunoprecipitation-qPCR was used to detect the m6A modification level of BZW2. Xenograft tumor models were constructed to confirm the effect of METTL3 knockdown on MM tumor growth in vivo. Our results showed that BZW2 was upregulated in MM bone marrow specimens and cells. BZW2 downregulation reduced MM cell proliferation and promoted apoptosis, while its overexpression enhanced MM cell proliferation and inhibited apoptosis. METTL3 was highly expressed in MM bone marrow specimens, and its expression was positively correlated with BZW2 expression. BZW2 expression was positively regulated by METTL3. Mechanistically, METTL3 could upregulate BZW2 expression by modulating its m6A modification. Additionally, METTL3 accelerated MM cell proliferation and restrained apoptosis via increasing BZW2 expression. In vivo experiments showed that METTL3 knockdown reduced MM tumor growth by decreasing BZW2 expression. In conclusion, these data indicated that METTL3-mediated the m6A methylation of BZW2 to promote MM progression, suggesting a novel therapeutic target for MM. [ABSTRACT FROM AUTHOR]

Ferrofluids are a type of nanometer-scale functional material with fluidity and superparamagnetism. They are composed of ferromagnetic particles, surfactants, and base liquids. The main characteristics of ferrofluids include magnetization, the magnetoviscous effect, and levitation characteristics. There are many mature commercial ferrofluid damping applications based on these characteristics that are widely used in numerous fields. Furthermore, some ferrofluid damping studies such as those related to vibration energy harvesters and biomedical devices are still in the laboratory stage. This review paper summarizes typical ferrofluid dampers and energy harvesting systems from the 1960s to the present, including ferrofluid viscous dampers, ferrofluid inertia dampers, tuned magnetic fluid dampers (TMFDs), and vibration energy harvesters. In particular, it focuses on TMFDs and vibration energy harvesters because they have been the hottest research topics in the ferrofluid damping field in recent years. This review also proposes a novel magnetic fluid damper that achieves energy conversion and improves the efficiency of vibration attenuation. Finally, we discuss the potential challenges and development of ferrofluid damping in future research. [ABSTRACT FROM AUTHOR]

Current research on spherical parallel mechanisms (SPMs) mainly focus on surgical robots, exoskeleton robots, entertainment equipment, and other fields. However, compared with the SPM, the structure types and research contents of the SPM are not abundant enough. In this paper, a novel two-degree-of-freedom (2DOF) SPM with symmetrical structure is proposed and analyzed. First, the models of forward kinematics and inverse kinematics are established based on D-H parameters, and the Jacobian matrix of the mechanism is obtained and verified. Second, the workspace of the mechanism is obtained according to inverse kinematics and link interference conditions. Next, rotational characteristics analysis shows that the end effector can achieve continuous rotation about an axis located in the mid-plane and passing through the rotation center of the mechanism. Moreover, the rotational characteristics of the mechanism are proved, and motion planning is carried out. A numerical example is given to verify the kinematics analysis and motion planning. Finally, some variant mechanisms can be synthesized. This work lays the foundation for the motion control and practical application of this 2DOF SPM. [ABSTRACT FROM AUTHOR]

Background: Clonorchis sinensis was a food-borne zoonotic parasite in the worldwide and also an important risk factor of hepatic fibrosis. Excretory/secretion products of C. sinensis (CsESPs) are involved in parasite-host interactions and contribute to the development of hepatic damage. The aim of the present study was to investigate whether CsESPs and CsTP (adult protein) could induce autophagy of hepatic stellate cells (HSCs) and further activate HSCs so as to participate in the pathogenesis of hepatic fibrosis. Methods and results: The human hepatic stellate cell line LX-2 was stimulated by CsESPs and CsTP. CsESPs showed the effect on cell proliferation in methyl thiazolyl tetrazolium (MTT) assay while CsTP failed. Autophagosomes and autolysosomes were observed after the transmission mRFP-EGFP-LC3 plasmid into the LX-2 cells. CsESPs had more powerful to induce the accumulation of autophagosomes and autolysosomes to enhance autophagic flux compared with CsTP. Western-blotting analysis confirmed that the ratio of LC3-II/I in LX-2 cells was up-regulated after CsESPs treatment for 6 h, which further proved that CsESPs could induce autophagy in LX-2 cells. Meanwhile, q-PCR results showed that the mRNA levels of collagen I, collagen III and α-SMA decreased in LX-2 cells after treatment with autophagy inhibitor chloroquine, whereas they increased when combination with CsESPs. Conclusions: These results suggested that CsESPs-induced autophagy might be involved in the activation of HSCs, and consequently participate in the pathogenesis of hepatic fibrosis caused by C. sinensis infection. [ABSTRACT FROM AUTHOR]

Computing the grain boundary (GB) counterparts to bulk phase diagrams represents an emerging research direction. Using a classical embrittlement model system Ga-doped Al alloy, this study demonstrates the feasibility of computing temperature- and composition-dependent GB diagrams to represent not only equilibrium thermodynamic and structural characters, but also mechanical properties. Specifically, hybrid Monte Carlo and molecular dynamics (MC/MD) simulations are used to obtain the equilibrium GB structure as a function of temperature and composition. Simulated GB structures are validated by aberration-corrected scanning transmission electron microscopy. Subsequently, MD tensile tests are performed on the simulated equilibrium GB structures. GB diagrams are computed for not only GB adsorption and structural disorder, but also interfacial structural and chemical widths, MD ultimate tensile strength, and MD tensile toughness. This study suggests a research direction to investigate GB composition–structure–property relationships via computing GB diagrams of thermodynamic, structural, and mechanical (or potentially other) properties. [ABSTRACT FROM AUTHOR]

Wound exudate holds great clinical and research potential in wound repair via paracrine signaling. In essence, exudate is modified serum that contains a high concentration of exosomes. The aim of this study was to investigate the role of serum-derived exosomes in scald wound healing of NIH mice skin and to explore the underlying mechanisms. Hence, we constructed a deep second-degree scald model in NIH mice, testing the benefits of exosomes in the scald wound healing. The scratch wound assay, apoptosis assay and MTT assay were conducted to assess the effects of serum-derived exosomes on migration, apoptosis and proliferation of HaCaT cells and fibroblasts. Our results showed that serum-derived exosomes injected subcutaneously entered cells and effectively accelerated wound healing processes in mice. Additionally, serum-derived exosomes optimized functions of cells related to skin injury repair by stimulating fibroblast proliferation, promoting HaCaT cell migration, and suppressing apoptosis of HaCaT cells induced by heat stress. Further study revealed that serum-derived exosomes enhanced phosphorylation of the serine-threonine kinase Akt in scalded skin tissue. These results suggest a potential clinical use of serum-derived exosomes for treating skin scald. [ABSTRACT FROM AUTHOR]

Titanium alloys are promising candidates for biomedical applications, and alloys based on the Ti-rich side of Ti-Nb-Sn system have presented material properties deserved for orthopedic implant applications. However, to our knowledge, the structural studies related to surface of these alloys are limited. Ti-18Nb-11Sn and Ti-35Nb-4Sn alloys were synthesized, and the influence of thermochemical treatment on the bioactivity was investigated. The alloys were synthesized by arc melting furnace and then were submitted to thermochemical treatment. X-ray diffraction and scanning electron micrograph analysis showed high crystallinity and maintenance of microstructure of the both alloys before and after thermochemical treatment. The results indicated that the Ti-18Nb-11Sn alloy was not demonstrated to be bioactive, while the Ti-35Nb-4Sn alloy slightly presented bioactivity, which increased after the thermochemical treatment. Meanwhile, the Ti-18Nb-11Sn alloy presented a low hardness value, making it not compatible with biomedical applications. However, the Ti-35Nb-4Sn alloy presented an acceptable hardness value for biomedical applications. We believe that the results reported herein suggest that the Ti-35Nb-4Sn alloy may be attractive for designing biomedical devices with improved performances toward the adhesion of apatite. [ABSTRACT FROM AUTHOR]

Cathepsin L-like protease is an important member of the papain-like cysteine protease and plays numerous indispensable roles in the biology of parasitic organisms. In a previous study, we identified a gene encoding a cathepsin L-like protease of Clonorchis sinensis (CsCPL) that was detected in the cercaria, metacercaria, and adult worm stages by immunolocalization, suggesting that this cysteine protease may be important and involved in the development of C. sinensis. In this study, the mature domain of CsCPL (CsCPL-m) was cloned and expressed in the form of inclusion bodies in Escherichia coli. After refolding, the recombinant CsCPL-m displayed optimal protease activity towards Z-Phe-Arg-AMC substrates but not towards Z-Arg-Arg-AMC, and the activity of the protease was inhibited completely by the cysteine protease-specific inhibitors E-64 and IAA, which further demonstrated that CsCPL belongs to the cathepsin L-like cysteine protease family. Recombinant CsCPL-m exhibited considerable activity at temperatures ranging from 28 to 42 °C, with the highest activity observed at 42 °C. Furthermore, recombinant CsCPL-m exhibited activity across a broad range of pH values (pH 4.0-8.0), with an optimal pH of 5.5. The Km and Vmax of the recombinant CsCPL-m towards Z-Phe-Arg-AMC were determined to be 5.71 × 10−6 M and 0.6 μM/min, respectively, at 37 °C and pH 5.5. The recombinant CsCPL-m could degrade BSA and gelatine, but could not degrade human hemoglobin and human immunoglobulin G. These results implied that CsCPL might participate in the catabolism of host proteins for nutrition during the parasitic life cycle of C. sinensis; thus, CsCPL could be used as a potential vaccine antigen and drug target against C. sinensis infection. [ABSTRACT FROM AUTHOR]

Gliomas are the most common primary brain tumors. This meta-analysis aimed to systematically evaluate the relationship between CD147 expression in tissues and the clinicopathological features of patients with glioma. We searched PubMed (1966-2016), EMBASE (1980-2016), Cochrane Library (1996-2016), Web of Science (1945-2016), China National Knowledge Infrastructure (1982-2016), and Wan Fang databases (1988-2016). Quality assessment of the literature was performed using the Newcastle-Ottawa Scale, with Revman 5.3 and Stata 14.0 for analysis. In total, 1806 glioma patients from 19 studies were included, and patients with CD147 overexpression had poorer overall survival [hazard ratio (HR) = 2.211, P < 0.0001], a higher risk of recurrence (HR = 2.20, P = 0.0025), and a lower 5-year survival rate [odds ratio (OR) 0.12; 95% CI 0.08-0.19; P < 0.00001]. We observed significant differences in CD147 expression when comparing glioma tissues versus non-cancerous brain tissues (OR 20.42; 95% CI 13.94-29.91; P < 0.00001), tumor grades III-IV versus grades I-II (OR 5.88, 95% CI 4.15-8.34; P < 0.00001), and large versus small tumors (OR 1.58, 95% CI 1.04-2.40; P = 0.03). We also observed a significant correlation with matrix metalloproteinase (MMP) 2 (OR 39.11, 95% CI 11.47-133.34; P < 0.00001) and MMP9 (OR 13.35, 95% CI 4.67-38.18; P < 0.00001). CD147 expression did not differ based on patient's age (young vs. old, P = 0.89) or gender (female vs. male, P = 0.57). CD147 expression may be a potential prognostic biomarker for poorer overall and relapse-free survival, and may affect the 5-year survival rate in glioma patients. CD147 expression is also closely correlated with poor clinical characteristics in glioma patients. [ABSTRACT FROM AUTHOR]

Polo-like kinase (Plk) plays a central role in centrosome cycle and is closely associated with the oncogenesis of lung cancer. The protein consists of a catalytic kinase domain (KD) and a regulatory polo-box domain (PBD); either direct inhibition of the KD's catalytic activity or indirect disruption of the PBD-substrate interaction can be used to potentially suppress the pathological activation of lung cancer Plk. Here, we reported a successful molecular design and engineering of phosphopeptide ligands to target Plk PBD domain by integrating in silico modeling and in vitro assay. In the procedure, a helical peptide segment hps was derived from dimerization interface of the complex crystal structure of domain dimer using bioinformatics approach, which was then used as sequence template to generate potent phosphopeptide binders of Plk PBD domain in terms of a systematic residue mutation profile. Fluorescence anisotropy assays were conducted to substantiate the findings and conclusions obtaining from the molecular engineering. Consequently, three helical phosphopeptides, including the native hps and its two mutants hps-m and hps-m , were successfully designed that can independently rebind to Plk PBD domain with a moderate or high affinity ( K = 127, 26, and 5 μM, respectively). These peptide ligands can be considered as potent self-competitors to disrupt PBD dimerization in lung cancer metastasis. Structural and energetic analysis revealed that hydrophobic forces and van der Waals contacts confer strong stability for domain-peptide complex system, while hydrogen bonds and electrostatic interactions contribute specificity and selectivity to the complex recognition. [ABSTRACT FROM AUTHOR]

Background: Paired box 6 (PAX6), a highly conserved transcriptional factor, has been implicated in tumorigenesis. Aim: We aimed to explore the roles and molecular mechanisms of PAX6 and microRNA (miR-7) in colorectal cancer cells. Methods: Tissue microarray immunohistochemistry and Western blot were applied to examine the PAX6 expression. Real-time RT-PCR and Western blot were performed to determine the expression of miR-7 and PAX6. Luciferase reporter assay was used to determine whether PAX6 was a target of miR-7. Effects of miR-7 and PAX6 on colorectal cell proliferation, cell cycle progression, colony formation and invasion were then investigated. Western blot was used to determine the activities of the ERK and PI3K signal pathways, as well as the protein expression of MMP2 and MMP9. Results: The protein levels of PAX6 were gradually increased, while the expression of miR-7 was gradually reduced with malignancy of colorectal cancer. PAX6 was further identified as a target of miR-7, and its protein expression was negatively regulated by miR-7 in human colorectal cancer cells. Overexpression of PAX6 in Caco-2 and SW480 cells enhanced cellular proliferation, cell cycle progression, colony formation, and invasion, while miR-7 upregulation repressed these biological processes. Furthermore, the activities of ERK and PI3K signal pathways, as well as the protein levels of MMP2 and MMP9, were upregulated in PAX6-overexpressed Caco-2 and SW480 cells but deregulated in miR-7-overexpressed Caco-2 and SW480 cells. Conclusions: Our study suggests that as a novel target of miR-7, PAX6 may serve as a promising therapeutic target for colorectal cancer. [ABSTRACT FROM AUTHOR]

Statistical inference often assumes the normality of the variables involved in the model under study. The existing tests are for independent observations and may not be readily extended to handle the case with correlated ones. In this paper, a transformation method is recommended for normality checking in the two-way analysis of variance model. Its sampling properties are investigated. Simulation studies are carried out to examine the performance of the proposed methodology. [ABSTRACT FROM AUTHOR]

Cysteine proteases (CPs) were associated with the pathogenicity and excystment of Clonorchis sinensis. Most of them were potential antigens for the immunodiagnosis of clonorchiasis. More researches on CPs will let us know more about their functions, and further employ them for the development of more efficient diagnostic reagent and prevention strategies. In the current study, a full-length sequence encoding cathepsin L from C. sinensis (CsCL41.5) was identified from our adult cDNA library. Bioinformatic analysis showed that CsCL41.5 included typical motifs of cathepsin L (ERFNIN and GNFD motifs) and conserved amino acid positions which constituted the active center of the enzyme. The identity of its amino acid sequence with the cathepsin L of Schistosoma japonicum was 49.6 %. Recombinant CsCL41.5 (rCsCL41.5) was highly expressed in the form of inclusion body in Escherichia coli, and soluble rCsCL41.5 was obtained after purification and renaturation. Western blotting analysis indicated that CsCL41.5 is an excretory-secretory antigen of C. sinensis adult. Immunolocalization demonstrated that CsCL41.5 is distributed in the intestine and eggs in the uterus of adult worm, tegument of metacercaria, oral suck, and tail of cercaria. ELISA assays showed that IgG4 was the predominant IgG isotype responding to rCsCL41.5 in sera from clonorchiasis patients. The sensitivity and specificity of specific IgG4 detection with rCsCL41.5 was 62.5 % (15/24) and 81.7 % (49/60), respectively. It was concluded that there were differences in biological function, efficiency of serodiagnosis, and characterization of immune reactivity between CsCL41.5 and other CPs of C. sinensis, combining with previous studies. [ABSTRACT FROM AUTHOR]

Clonorchiasis is a common zoonosis in southern and northeastern parts of China, especially in Guangdong, Guangxi and Jilin province. Anti- Clonorchis sinensis antibody detection by enzyme-linked immunosorbent assay (ELISA) has been used for epidemiological surveys of clonorchiasis for its convenience and celerity, but it is still a meaningful work to screen ideal diagnostic antigen or antibody subtype for improvement of diagnostic sensitivity and specificity and for judgement of curative effect. In the present study, recombinant CsCatL-propeptide (rCsCatL-propeptide) was highly expressed in form of inclusion body in Escherichia coli. Soluble rCsCatL-propeptide with high purity were obtained after purification in denatured condition by using His Bind Purification kit, and then renatured. The major antibody subtypes responding to rCsCatL-propeptide in sera from clonorchiasis patients were IgG1 and IgG4, but the level of IgG4 was more predominant ( P < 0.05). The sensitivity of specific IgG4 detection (91.7%) was statistically significantly higher than that of IgG1 (25.0%) with rCsCatL-propeptide ( P < 0.01). The specificities of IgG1 and IgG4 detection with rCsCatL-propeptide were 83.3% and 88.5%, respectively, and the difference between them was not statistically significant ( P > 0.05). Cross-reactions took place when we detected IgG1 of sera from patients infected with Schistosoma japonicum, Paragonimus westermani, hookworm, Trichuris trichiura and Ascaris lumbricoides with rCsCatL-propeptide, while cross-reactions only took place in sera from patients infected with S. japonicum and P. westermani when we detected specific IgG4. The positive rate of IgG4 detection in sera from clonorchiasis patients with <1,000, 1,000-4,999, 5,000-9,999, and ≥10,000 eggs per gram faeces (EPG) were 76.9%, 89.3%, 95.6%, and 100.0%, respectively. The positive rates of serodiagnosis correlated well with the EPG ( r = 0.93). Overall, rCsCatL-propeptide is a valuable candidate for specific IgG4 detection in sera from clonorchiasis patients by the method of ELISA for its few cross-reaction and acceptable sensitivity. In addition, specific IgG4 detection can be used to valuate infected degree and therapeutic effect of clonorchiasis patients. [ABSTRACT FROM AUTHOR]

Several important developing phases of the formulas for mobility calculation based on constraints are introduced. The shortcoming of the mobility formulas based on common constraints of loops of a mechanism is that virtual constraints must be calculated before determining the mobility of a mechanism with virtual constraints. In order to avoid the shortcoming, some new concepts including virtual loop, virtual-loop constraint and general-kinematic-pair constraint are used to analyze the relationship between mobility of links and constraint of kinematic pairs and a mobility formula based on common constraints of virtual loops is proposed. The formula is that the number of mobility of a mechanism is the sum of mobility of all links in the mechanism minus the sum of constraints of all kinematic pairs plus the sum of the common constraints of all virtual loops. The sum of over constraints of a mechanism is the sum of constraints of all virtual loops in the mechanism. This mobility formula expressed in terms of common constraints of virtual loops in a mechanism can avoid calculating virtual constraints. It is proved that the new formula is correct, simple and effective through the analysis of several different kinds of mechanisms. [ABSTRACT FROM AUTHOR]

The association of enteroviruses with myocardial disease has been investigated extensively by molecular biological techniques to detect viral RNA, but remains controversial. This retrospective study investigated the involvement of enterovirus in myocarditis or dilated cardiomyopathy (DCM) by detection of viral antigens in myocardial samples from a new patient series using an optimized immunohistochemical technique. Formalin-fixed, paraffin-embedded biopsy, autopsy or explanted myocardial tissue samples were obtained from 136 subjects. These comprised histologically proven cases of acute fatal myocarditis (n=10), DCM (n=89, including 10 patients with healing/borderline myocarditis) and a comparison group of samples from 37 unused donor hearts and cases with other conditions. A monoclonal antibody 5-D8/1 directed against a conserved, non-conformational epitope in capsid protein VP1 was employed for broad detection of different enterovirus serotypes. Investigations were performed blindly. Histological sections from 7 of 10 fatal myocarditis cases, 47 of 89 patients (52.8%) with DCM were positive for the viral capsid protein VP1 by immunohistochemical staining. Consecutive sections of positive samples were negative when the antibody was omitted or replaced with subclass- and concentration-matched normal mouse IgG. In contrast, only 3 of 37 samples (8.1%) in the comparison group were positive (Yates corrected χ2=19.99, P<0.001: odds ratio =12.68). VP1 staining was distributed in individual or grouped myofibers and localized in the cytoplasm of myocytes. In some cases, VP1 was detected in only a few myofibers within an entire section. These results provide further evidence of enterovirus involvement in a high proportion of DCM cases and demonstrate that VP1 is present in disease stages from acute myocarditis, healing myocarditis to end-stage DCM requiring cardiac transplantation, indicating translation of viral protein during persistent enterovirus infection. [ABSTRACT FROM AUTHOR]

Small interfering RNAs (siRNAs) may induce to targeted gene knockdown, and the gene silencing effectiveness relies on the efficacy of the siRNA. Therefore, the task of this paper is to construct an effective siRNA prediction method. In our work, we try to describe siRNA from both quantitative and qualitative aspects. For quantitative analyses, we form four groups of effective features, including nucleotide frequencies, thermodynamic stability profile, thermodynamic of siRNA-mRNA interaction, and mRNA related features, as a new mixed representation, in which thermodynamic of siRNA-mRNA interaction is introduced to siRNA efficacy prediction for the first time to our best knowledge. And then an F-score based feature selection is employed to investigate the contribution of each feature and remove the weak relevant features. Meanwhile, we encode the siRNA sequence and existed empirical design rules as a qualitative siRNA representation. These two kinds of siRNA representations are combined to predict siRNA efficacy by supported Vector Regression (SVR) at score level. The experimental results indicate that our method may select the features with powerful discriminative ability and make the two kinds of siRNA representations work at full capacity. The prediction results also demonstrate that our method can outperform other popular siRNA efficacy prediction algorithms. [ABSTRACT FROM AUTHOR]