243 research outputs found

    The Relationship between Fungal Growth Rate and Temperature and Humidity

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    In order to determine the relation among the three factors of wood fiber decomposition rate, mycelial elongation and moisture resistance, our team resorted to the Monod equation and the modified Logistic equation. Combing with the kinetic principle and the law of mass action, the equations between the decomposition rate of wood fiber, the elongation rate of mycelium and the moisture resistance were established. In the course of solving the model, we found that when the temperature ranges from 24℃ to 28℃ and the relative humidity from 60% to75%, the growth rate of fungi is the fastest

    Isolation and antibacterial activity of anabaena phycocyanin

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    The isolation and antibacterial activity of anabaena phycocyanin were investigated. The result indicates that three kinds of protein ingredients: PC-A, PC-B and PC-C were obtained using high performance liquid chromatography. The estimated molecular masses of PC-A and PC-B were 14 to 18 kD. PC-B and PC-C had certain antibacterial activity on Bibrio parahemolyticus, Bacillus mucilaginosus and Sarcina lutea. In addition, PC-C had certain antibacterial activity on Vibrio harveyi. PC-A did not possess antibacterial activity in the study.Keywords: Anabaena, phycocyanin, liquid chromatogram, antibacterialAfrican Journal of Biotechnology Vol. 12(15), pp. 1869-187

    An Investigation of Syntactic Errors in Chinese Undergraduate EFL Learners’ Compositions: A Cohort Study

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    TRIM 16 gene expression regulates the growth and metastasis of human esophageal cancer

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    Purpose: To investigate the effect of tripartite membrane protein  TRIM) 16 gene silencing on human esophageal cancer (KYSE-270) cell proliferation, invasion and metastasis.Methods: Short interfering RNA (siRNA) TRIM 16 silencing fragment was transfected into KYSE-270 cells. Transfection efficiency was determined using real-time quantitative polymerase chain reaction (qRT-PCR). Cell proliferation, invasiveness and migration were measured by 3-(4,5-dimethylthiazol2-yl)- 2,5-diphenyl tetrazolium bromide (MTT) assay, Transwell invasion assay, and scratch test, respectively. Protein expressions of bax and bcl-2 were assayed using Western blotting.Results: The gene expression of TRIM 16 was significantly upregulated in esophageal cancer cells, relative to normal human esophageal cells, but was downregulated after gene silencing. Moreover, the silencing of TRIM 16 gene led to significant reductions in KYSE-270 cell viability, migration and invasiveness, but significantly increased KYSE270 cell apoptosis (p < 0.05). The silencing of TRIM 16 gene also significantly upregulated bax protein expression, while downregulating the expression of bcl-2 protein (p < 0.05).Conclusion: These results suggest that TRIM 16 gene silencing inhibits KYSE-270 cell proliferation, invasion and metastasis, and thus provide a basis for its development as a therapeutic approach for the management of esophageal cancer. Keywords: Apoptosis, Cell invasion, Esophageal cancer, Gene silencing, Metastasi

    Modeling of pneumatic actuator system for high performance nonlinear controller design,"

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    ABSTRACT Modern applications in robotics such as teleoperations and haptics require high performance force actuators. Pneumatic actuators have significant advantages over electrical motors in terms of force-to-mass ratio. However, position and force control of these actuators in applications that require high bandwidth is not trivial because of the compressibility of air and highly nonlinear flow through pneumatic system components. In this paper, we develop a detailed model of a pneumatic actuator system comprised of a double acting cylinder and a proportional servo valve to be used in position, force or hybrid position and force control. NOMENCLATURE R Ideal gas constant C v Specific heat at constant volume C p Specific heat at constant pressure k Specific heat ratio P Pressure of gas V Volume of gas ρ Density of gas T Temperature of gaṡ m Mass flow rate * Corresponding author.ṁ en Mass flow rate entering to the controlled volume of gaṡ m ex Mass flow rate exiting from the controlled volume of gaṡ Q Heat transfer rate to the controlled volume of gas h en Enthalpy of the gas entering to the controlled volume of gas h ex Enthalpy of the gas exiting from the controlled volume of gas v en Velocity of the gas entering to the controlled volume of gas v ex Velocity of the gas exiting from the controlled volume of gas E Total energy of the controlled volume of gas U Internal energy of control volume of gas W Work delivered by the controlled volume of gas to the envi- INTRODUCTION Modern existing and emerging new applications in robotics require high performance force actuators or hybrid force and position actuators with high force output per unit weight. Compared to traditional geared electrical motors and hydraulic actuators, pneumatic actuators have several advantages [1] in these applications beside their being low cost and clean-operation. Pneumatic actuators can also provide static high force output for a long duration without additional cooling systems as in the case of direct drive electrical motors. However, position and force control of these actuators in applications that require high bandwidth is difficult because of the compressibility of air and the highly nonlinear flow through pneumatic system components. Due to these difficulties, early use of pneumatic actuators had been limited to simple applications that require only positioning at the two ends of the piston stroke. With the increasingly in-depth understanding of the thermodynamics and flow characteristics [2], linear position controllers have been developed To study the control aspects of pneumatic actuators for applications in precision position control, force control and hybrid position and force control, we developed a simple pneumatic testbed that consists of a double acting cylinder with rods and proportional servo valve connected by tubes. In this paper, we derive a detailed model of the pneumatic actuator system

    Dissecting causal associations of type 2 diabetes with 111 types of ocular conditions: a Mendelian randomization study

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    BackgroundDespite the well-established findings of a higher incidence of retina-related eye diseases in patients with diabetes, there is less investigation into the causal relationship between diabetes and non-retinal eye conditions, such as age-related cataracts and glaucoma.MethodsWe performed Mendelian randomization (MR) analysis to examine the causal relationship between type 2 diabetes mellitus (T2DM) and 111 ocular diseases. We employed a set of 184 single nucleotide polymorphisms (SNPs) that reached genome-wide significance as instrumental variables (IVs). The primary analysis utilized the inverse variance-weighted (IVW) method, with MR-Egger and weighted median (WM) methods serving as supplementary analyses.ResultsThe results revealed suggestive positive causal relationships between T2DM and various ocular conditions, including “Senile cataract” (OR= 1.07; 95% CI: 1.03, 1.11; P=7.77×10-4), “Glaucoma” (OR= 1.08; 95% CI: 1.02, 1.13; P=4.81×10-3), and “Disorders of optic nerve and visual pathways” (OR= 1.10; 95% CI: 0.99, 1.23; P=7.01×10-2).ConclusionOur evidence supports a causal relationship between T2DM and specific ocular disorders. This provides a basis for further research on the importance of T2DM management and prevention strategies in maintaining ocular health

    HPV16 E7 oncoprotein test as a triage strategy for HPV16-positive women in cervical cancer screening: long-term follow-up outcome

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    BackgroundColposcopy is recommended once human papillomavirus (HPV)16/18 infection is detected. However, not all HPV16/18-positive women will necessarily develop cervical lesions. Therefore, this study aimed to investigate the application of quantitative HPV16 E7 oncoprotein detection as a cervical cancer screening method for more efficient screening while minimizing unnecessary colposcopy.MethodsE7 oncoprotein (HPV16) was quantitatively detected in cervical exfoliated cells of HPV16-positive women. The levels of HPV16 E7 oncoprotein in different degrees of cervical lesions were compared, and the optimal cut-off value for identifying HSIL+ was determined by receiver operating characteristic (ROC) curve analysis. With a pathological diagnosis as the gold standard, the sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV), and Kappa value were calculated to verify the diagnostic value of the method. Women diagnosed with low-grade squamous intraepithelial lesions (LSIL) and normal women were followed up for 5 years to evaluate the predictive value of HPV16 E7 protein for disease progression/persistent infection.ResultsThe expression level of HPV16 E7 oncoprotein was positively correlated with the degree of the cervical lesion (r = 0.589, P < 0.01). The area under the ROC curve (AUC) was 0.817 (confidence interval: 0.729–0.904). The cut-off value of E7 oncoprotein for identifying HSIL+ was 8.68 ng/ml. The SEN, SPE, PPV, NPV, and Kappa values of HPV16 E7 oncoprotein for the identification of HSIL+ were 87.1%,70.0%, 87.1%, 70.0%, and 0.571, respectively, which were higher than those of ThinPrep cytology test (TCT). The SEN, SPE, PPV, and NPV of HPV16 E7 oncoprotein in predicting disease progression/persistent infection were 93.75%, 91.30%, 88.24%, and 95.45%, respectively.ConclusionThe quantitative detection of HPV 16 E7 oncoprotein can not only accurately screen cervical lesions but also achieve efficient colposcopy referral. Additionally, HPV16 E7 oncoprotein can accurately predict the progression of cervical lesions and persistent HPV infection

    Protective Mechanism of Adipose-Derived Stem Cells in Remodelling of the Skin Stem Cell Niche During Photoaging

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    Background/Aims: Skin photoaging is primarily caused by the functional attrition of skin stem cells. The skin stem cell niche plays an important role in maintaining stem cell survival and behaviour. In our study, we hypothesized that UVB irradiation induces skin photoaging by changing skin stem cell niches and that transferred adipose-derived stem cells (ADSCs) can remodel the niches by affecting the BMP signalling pathway and transdifferentiating into skin stem cells. Methods: Sixty-four C57BL/6J mice were divided into the following groups: a control group, the UVB group and the UVB+ADSCs group. Western blot assays, immunofluorescence analysis and real-time PCR were used to measure differences in the expression of niche components among the three groups. Furthermore, we tested whether transplanted ADSCs express skin stem cell markers, such as p63, α6-integrin and CD34. Results: The expression levels of Bmp4, its downstream factors Smad1 and MAPK1 and a regulatory factor of the niche, i.e., NFATc1, were lower in the UVB group than were those in the control group (P< 0.05) but higher in the UVB+ADSCs group than were those in the UVB group (P< 0.05). Compared with Bmp4, Nanog (a downstream factor of Bmp4), and MMP13 (a regulatory factor of the niche), ICAM-1 (a proinflammatory gene), p63 (a basal transcription factor), β1-integrin, Mtnr1a and Tyr (melanogenesis-related factors) showed the opposite expression trends (P< 0.05). Bmp2 and Collagen IV levels did not significantly change among the three groups (P> 0.05). Skin stem cell markers, such as p63, α6-integrin and CD34, were coexpressed in the ADSCs, which suggested the ADSCs may transdifferentiate into skin stem cells. Conclusion: We found that UVB irradiation results in typical photoaging signs by altering skin stem cell niches and that Bmp4 was a key factor in BMP signalling in hair follicles. ADSCs reversed these typical photoaging signs by remodelling skin stem cell niches through BMP4 pathway modulation and transdifferentiation into skin stem cells

    Causal effects from inflammatory bowel disease on liver function and disease: a two-sample Mendelian randomization study

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    BackgroundAccumulating evidence has shown that patients with inflammatory bowel disease (IBD) have liver function abnormalities and are susceptible to liver diseases. However, the existence of a causal relationship between IBD and liver function or disease remains unclear.MethodsA two-sample Mendelian randomization (MR) analysis was performed using genetic associations from publicly available genome-wide association studies (GWAS). These associations encompass ulcerative colitis (UC), Crohn’s disease (CD), liver function traits, and liver disease phenotypes. The liver function traits comprised hepatic biochemistries, percent liver fat, and liver iron content from the UK Biobank. Furthermore, the liver disease phenotypes included cholelithiasis, non-alcoholic fatty liver disease (NAFLD), primary sclerosing cholangitis (PSC), and primary biliary cholangitis (PBC) in cohorts of European ancestry. The primary estimation used the inverse-variance weighted method, with GWAS of C-reactive protein (CRP) in the UK Biobank serving as a positive control outcome.ResultsGenetically predicted UC is causally associated with decreased levels of albumin (ALB) and liver iron content, while genetically predicted CD is causally associated with increased levels of alkaline phosphatase (ALP). Moreover, genetically predicted UC or CD increases the risk of PSC, and CD increases the risk of PBC. Neither UC nor CD causally increases the risk of cholelithiasis and NAFLD.ConclusionUC affects the levels of ALB and liver iron content, while CD affects the levels of ALP. Both UC and CD increase the risk of PSC, and CD increases the risk of PBC
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