223 research outputs found
Microstructure refinement by tool rotation-induced vibration in incremental sheet forming
This paper presents a study of employing tool rotation-induced vibrations in incremental sheet forming (V-ISF) to produce sheet metal parts with laminated ultrafine-grained structures. Non-axisymmetric tools were developed to generate tool vibration and surface shear deformation of sheet material during forming. Using the V-ISF process, magnesium sheets of AZ31 were formed to the hyperbolic cones and laminated ultrafine grains with higher micro hardness were obtained by tool generated low frequency vibrations with large amplitudes. To further investigate surface shear deformation induced during processing, the hole-deformation analysis of samples cut from the formed hyperbolic cones was performed. This study found that large surface shear deformation of the sheet and the tool vibration during incremental forming are the two key factors for the formation of laminated ultrafine grains. The developed V-ISF process has a great potential to produce sheet metal parts with refined grains and greater micro hardness
Pathogens and drug resistance in active surveillance of foodborne diseases from 2017 to 2019 in Chenzhou City
ObjectiveTo provide a scientific basis for the prevention and control of foodborne diseases in Chenzhou, the etiological characteristics and epidemiological patterns of foodborne diseases were analyzed.MethodsThe Case information and stool and anal swab samples were collected from two sentinel hospitals in Chenzhou in 2017 and 2019. According to the methods described in “National Manual of Foodborne Disease Surveillance”, the samples were tested for pathogens, pathogen typing, and drug sensitivity.ResultsA total of 825 samples of diarrhea cases were collected, and the total detection rate of pathogens was 30.18% (249/825), including 16.24% (134/825) Salmonella, 11.76% (97/825) Norovirus, 3.52% (29/825) diarrheal Escherichia coli, 0.73% (6/825) Vibrio parahaemolyticus, and 0.12% (1/825) Shigella. Bacterial detection rates were higher in the second and third quarters than in other quarters, and viral detection rates were higher in the first and fourth quarters than in other quarters. The highest pathogen detection rate was 40.79% (31/76) in the 2-6-year-old group. Milk and dairy products, grains and their products, and fruits and their products were suspected foods. The highest detection rate in Salmonella was in Salmonella enterica subsp.(74.63%, 100/134), the highest detection rate in diarrheal Escherichia coli was in intestinal adhesion type and enterotoxin type (34.48%, 10/29), and the norovirus was mainly GII type (85.57%, 83/97). The highest resistance rate of Salmonella to tetracycline was 88.71% (110/124), and the multidrug resistance rate of Salmonella was 85.48% (106/124). The resistance rate of diarrheal Escherichia coli to ampicillin was significant (79.31%, 23/29), and the multidrug resistance rate of diarrheal Escherichia coli was 62.07% (18/29).ConclusionThe main pathogens of diarrheal cases of foodborne diseases were Salmonella and Norovirus in Chenzhou. Salmonella and diarrheal Escherichia coli are highly resistant to antibiotics. Therefore, it is necessary to conduct targeted food safety supervision, strengthen antibiotic resistance monitoring, and strictly prevent antibiotic abuse
Ganoderma lucidum polysaccharides in human monocytic leukemia cells: from gene expression to network construction
<p>Abstract</p> <p>Background</p> <p><it>Ganoderma lucidum </it>has been widely used as a herbal medicine for promoting health and longevity in China and other Asian countries. Polysaccharide extracts from <it>Ganoderma lucidum </it>have been reported to exhibit immuno-modulating and anti-tumor activities. In previous studies, F3, the active component of the polysaccharide extract, was found to activate various cytokines such as IL-1, IL-6, IL-12, and TNF-<it>α</it>. This gave rise to our investigation on how F3 stimulates immuno-modulating or anti-tumor effects in human leukemia THP-1 cells.</p> <p>Results</p> <p>Here, we integrated time-course DNA microarray analysis, quantitative PCR assays, and bioinformatics methods to study the F3-induced effects in THP-1 cells. Significantly disturbed pathways induced by F3 were identified with statistical analysis on microarray data. The apoptosis induction through the DR3 and DR4/5 death receptors was found to be one of the most significant pathways and play a key role in THP-1 cells after F3 treatment. Based on time-course gene expression measurements of the identified pathway, we reconstructed a plausible regulatory network of the involved genes using reverse-engineering computational approach.</p> <p>Conclusion</p> <p>Our results showed that F3 may induce death receptor ligands to initiate signaling via receptor oligomerization, recruitment of specialized adaptor proteins and activation of caspase cascades.</p
Estrogen receptor α (ERα) mediates 17β-estradiol (E2)-activated expression of HBO1
BACKGROUND: HBO1 (histone acetyltransferase binding to ORC1) is a histone acetyltransferase (HAT) which could exert oncogenic function in breast cancer. However, the biological role and underlying mechanism of HBO1 in breast cancer remains largely unknown. In the current study, we aimed to investigate the role of HBO1 in breast cancer and uncover the underlying molecular mechanism. METHODS: Immunohistochemistry was applied to detect HBO1 protein expression in breast cancer specimens (n = 112). The expression of protein level was scored by integral optical density (IOD) for further statistical analyses using SPSS. Real-time PCR was used to simultaneously measure mRNA levels of HBO1. The HBO1 protein expression in breast cancer cells was confirmed by western blot. RESULTS: HBO1 was highly expressed in breast cancer tissues and significantly correlated with estrogen receptor α (ERα) (p < 0.001) and progestational hormone (PR) (p = 0.002). HBO1 protein level also correlated positively with histology grade in ERα positive tumors (p = 0.016) rather than ERα negative tumors. 17β-estradiol (E2) could upregulate HBO1 gene expression which was significantly inhibited by ICI 182,780 or ERα RNAi. E2-increased HBO1 protein expression was significantly suppressed by treatment with inhibitor of MEK1/2 (U0126) in T47 D and MCF-7 cells. CONCLUSIONS: HBO1 was an important downstream molecule of ERα, and ERK1/2 signaling pathway may involved in the expression of HBO1 increased by E2
Maternal exposure to ambient air pollution and congenital heart defects in China
Background: Evidence of maternal exposure to ambient air pollution on congenital heart defects (CHD) has been mixed and are still relatively limited in developing countries. We aimed to investigate the association between maternal exposure to air pollution and CHD in China.Method: This longitudinal, population-based, case-control study consecutively recruited fetuses with CHD and healthy volunteers from 21 cities, Southern China, between January 2006 and December 2016. Residential address at delivery was linked to random forests models to estimate maternal exposure to particulate matter with an aerodynamic diameter of ≤1 µm (PM1), ≤2.5 µm, and ≤10 µm as well as nitrogen dioxides, in three trimesters. The CHD cases were evaluated by obstetrician, pediatrician, or cardiologist, and confirmed by cardia ultrasound. The CHD subtypes were coded using the International Classification Diseases. Adjusted logistic regression models were used to assess the associations between air pollutants and CHD and its subtypes.Results: A total of 7055 isolated CHD and 6423 controls were included in the current analysis. Maternal air pollution exposures were consistently higher among cases than those among controls. Logistic regression analyses showed that maternal exposure to all air pollutants during the first trimester was associated with an increased odds of CHD (e.g., an interquartile range [13.3 µg/m3] increase in PM1 was associated with 1.09-fold ([95% confidence interval, 1.01-1.18]) greater odds of CHD). No significant associations were observed for maternal air pollution exposures during the second trimester and the third trimester. The pattern of the associations between air pollutants and different CHD subtypes was mixed.Conclusions: Maternal exposure to greater levels of air pollutants during the pregnancy, especially the first trimester, is associated with higher odds of CHD in offspring. Further longitudinal well-designed studies are warranted to confirm our findings
Anapole mediated giant photothermal nonlinearity in nanostructured silicon
Featured with a plethora of electric and magnetic Mie resonances, high index
dielectric nanostructures offer a versatile platform to concentrate
light-matter interactions at the nanoscale. By integrating unique features of
far-field scattering control and near-field concentration from radiationless
anapole states, here, we demonstrate a giant photothermal nonlinearity in
single subwavelength-sized silicon nanodisks. The nanoscale energy
concentration and consequent near-field enhancements mediated by the anapole
mode yield a reversible nonlinear scattering with a large modulation depth and
a broad dynamic range, unveiling a record-high nonlinear index change up to 0.5
at mild incident light intensities on the order of MW/cm2. The observed
photothermal nonlinearity showcases three orders of magnitude enhancement
compared with that of unstructured bulk silicon, as well as nearly one order of
magnitude higher than that through the radiative electric dipolar mode. Such
nonlinear scattering can empower distinctive point spread functions in confocal
reflectance imaging, offering the potential for far-field localization of
nanostructured Si with an accuracy approaching 40 nm. Our findings shed new
light on active silicon photonics based on optical anapoles
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Co-targeting of FAK and MDM2 triggers additive anti-proliferative effects in mesothelioma via a coordinated reactivation of p53
Background: Improved mesothelioma patient survival will require development of novel and more effective pharmacological interventions. TP53 genomic mutations are uncommon in mesothelioma, and recent data indicate that p53 remains functional, and therefore is a potential therapeutic target in these cancers. In addition, the tumour suppressor NF2 is inactivated by genomic mechanisms in more than 80% of mesothelioma, causing upregulation of FAK activity. Because FAK is a negative regulator of p53, NF2 regulation of FAK–p53–MDM2 signalling loops were evaluated. Methods: Interactions of FAK–p53 or NF2–FAK were evaluated by phosphotyrosine-p53 immunoaffinity purification and tandem mass spectrometry, and p53, FAK, and NF2 immunoprecipitations. Activation and/or expression of FAK, p53, and NF2 were also evaluated in mesotheliomas. Effects of combination MDM2 and FAK inhibitors/shRNAs were assessed by measuring mesothelioma cell viability/growth, expression of cell cycle checkpoints, and cell cycle alterations. Results: We observed constitutive activation of FAK, a known negative regulator of p53, in each of 10 mesothelioma cell lines and each of nine mesothelioma surgical specimens, and FAK was associated with p53 in five of five mesothelioma cell lines. In four mesotheliomas with wild-type p53, FAK silencing by RNAi induced expression and phosphorylation of p53. However, FAK regulation of mesothelioma proliferation was not restricted to p53-dependent pathways, as demonstrated by immunoblots after FAK knockdown in JMN1B mesothelioma cells, which have mutant/inactivated p53, compared with four mesothelioma cell lines with nonmutant p53. Additive effects were obtained through a coordinated reactivation of p53, by FAK knockdown/inhibition and MDM2 inhibition, as demonstrated by immunoblots, cell viability, and cell-cycle analyses, showing increased p53 expression, apoptosis, anti-proliferative effects, and cell-cycle arrest, as compared with either intervention alone. Our results also indicate that NF2 regulates the interaction of FAK–p53 and MDM2–p53. Conclusions: These findings highlight novel therapeutic opportunities in mesothelioma
Flow characteristics and intrinsic workability of IN718 superalloy
This study focuses on deformation characteristics of superalloy IN718 by formulation of a new flowstress model and detailed evaluation of intrinsic workability through the generation of three-dimensional (3D) processing maps with the support of optical microstructural observations. Based on thermomechanical simulation tests using a Gleeble-1500 machine, the flow stress model for superalloy IN718 was built and the flow stress throughout the entire deformation process was described by a peak stress only depending on Zener–Hollomon parameter and strain. The developed model exhibited the strain softening due to dynamic recrystallization (DRX). The intrinsic workability was further investigated by constructing 3D processing maps. The 3D processing maps described the variations of the efficiency of power dissipation and flow instability domains as a function of strain rate, temperature and strain, from which the favourite deformation conditions for thermomechanical processing of IN718 can be established
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Targeting SALL4 by entinostat in lung cancer
The overall survival of lung cancer patients remains dismal despite the availability of targeted therapies. Oncofetal protein SALL4 is a novel cancer target. We herein report that SALL4 was aberrantly expressed in a subset of lung cancer patients with poor survival. SALL4 silencing by RNA interference or SALL4 peptide inhibitor treatment led to impaired lung cancer cell growth. Expression profiling of SALL4-knockdown cells demonstrated that both the EGFR and IGF1R signaling pathways were affected. Connectivity Map analysis revealed the HDAC inhibitor entinostat as a potential drug in treating SALL4-expressing cancers, and this was confirmed in 17 lung cancer cell lines. In summary, we report for the first time that entinostat can target SALL4-positive lung cancer. This lays the foundation for future clinical studies evaluating the therapeutic efficacy of entinostat in SALL4-positive lung cancer patients
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