126 research outputs found

    On the sharp constant for starlikeness

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    We obtain a sharp constant of the sufficient condition for p-valently starlikeness, which had been studied by Nunokawa (1991), Obradović and Owa (1989), and Li (1993)

    Expression of endo-1, 4-beta-xylanase from Trichoderma reesei in Pichia pastoris and functional characterization of the produced enzyme

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    <p>Abstract</p> <p>Background</p> <p>In recent years, xylanases have attracted considerable research interest because of their potential in various industrial applications. The yeast <it>Pichia pastoris </it>can neither utilize nor degrade xylan, but it possesses many attributes that render it an attractive host for the expression and production of industrial enzymes.</p> <p>Results</p> <p>The Xyn2 gene, which encodes the main <it>Trichoderma reesei </it>Rut C-30 endo-β-1, 4-xylanase was cloned into the pPICZαA vector and expressed in <it>Pichia pastoris</it>. The selected <it>P. pastoris </it>strains produced as 4,350 nkat/ml β-xylanase under the control of the methanol inducible alcohol oxidase 1 (<it>AOX1</it>) promoter. The secreted recombinant Xyn2 was estimated by SDS-PAGE to be 21 kDa. The activity of the recombinant Xyn2 was highest at 60°C and it was active over a broad range of pH (3.0–8.0) with maximal activity at pH 6.0. The enzyme was quite stable at 50°C and retained more than 94% of its activity after 30 mins incubation at this temperature. Using Birchwood xylan, the determined apparent <it>K</it><sub>m </sub>and k<sub>cat </sub>values were 2.1 mg/ml and 219.2 S<sup>-1</sup>, respectively. The enzyme was highly specific towards xylan and analysis of xylan hydrolysis products confirmed as expected that the enzyme functions as endo-xylanase with xylotriose as the main hydrolysis products. The produced xylanase was practically free of cellulolytic activity.</p> <p>Conclusion</p> <p>The <it>P. pastoris </it>expression system allows a high level expression of xylanases. Xylanase was the main protein species in the culture supernatant, and the functional tests indicated that even the non-purified enzyme shows highly specific xylanase activity that is free of cellulolytic side acitivities. Therefore, <it>P pastoris </it>is a very useful expression system when the goal is highly specific and large scale production of glycosyl hydrolases.</p

    Paradigm of Time-sequence Development of the Intestine of Suckling Piglets with Microarray

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    The interaction of the genes involved in intestinal development is the molecular basis of the regulatory mechanisms of intestinal development. The objective of this study was to identify the significant pathways and key genes that regulate intestinal development in Landrace piglets, and elucidate their rules of operation. The differential expression of genes related to intestinal development during suckling time was investigated using a porcine genome array. Time sequence profiles were analyzed for the differentially expressed genes to obtain significant expression profiles. Subsequently, the most significant profiles were assayed using Gene Ontology categories, pathway analysis, network analysis, and analysis of gene co-expression to unveil the main biological processes, the significant pathways, and the effective genes, respectively. In addition, quantitative real-time PCR was carried out to verify the reliability of the results of the analysis of the array. The results showed that more than 8000 differential expression transcripts were identified using microarray technology. Among the 30 significant obtained model profiles, profiles 66 and 13 were the most significant. Analysis of profiles 66 and 13 indicated that they were mainly involved in immunity, metabolism, and cell division or proliferation. Among the most effective genes in these two profiles, CN161469, which is similar to methylcrotonoyl-Coenzyme A carboxylase 2 (beta), and U89949.1, which encodes a folate binding protein, had a crucial influence on the co-expression network

    Status Epilepticus due to Intraperitoneal Injection of Vehicle Containing Propylene Glycol in Sprague Dawley Rats

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    Published reports of status epilepticus due to intraperitoneal injection containing propylene glycol in rats are sparse. In fact, there are no reports specifying a maximum safe dose of propylene glycol through intraperitoneal administration. We report here a case of unexpected seizures in Sprague Dawley rats after receiving an intraperitoneal injection containing propylene glycol. Nine-week-old, 225–250 gram male rats were reported to experience tremor progressing to seizures within minutes after given injections of resveratrol (30 mg/kg) dissolved in a 40 : 60 propylene glycol/corn oil vehicle solution by direct intraperitoneal (IP) slow bolus injection or via a preplaced intraperitoneal catheter. The World Health Organization suggests a maximum dose of 25 mg/kg/day of propylene glycol taken orally and no more than 25 mg/dL in blood serum, whereas the animals used in our study got a calculated maximum 0.52 g/kg (25 times lower dose). Blood tests from the seizing rat support a diagnosis of hemolysis and lactic acidosis which may have led to the seizures, all of which appeared to be a consequence of the propylene glycol administration. These findings are consistent with oral and intravenous administration of propylene glycol toxicity as previously reported in other species, including humans. To our knowledge, this report represents the first published case of status epilepticus due to an IP injection containing propylene glycol

    Social visual preference mediates the effect of cortical thickness on symptom severity in children with autism spectrum disorder

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    BackgroundEvidence suggests that there is a robust relationship between altered neuroanatomy and autistic symptoms in individuals with autism spectrum disorder (ASD). Social visual preference, which is regulated by specific brain regions, is also related to symptom severity. However, there were a few studies explored the potential relationships among brain structure, symptom severity, and social visual preference.MethodsThe current study investigated relationships among brain structure, social visual preference, and symptom severity in 43 children with ASD and 26 typically developing (TD) children (aged 2–6 years).ResultsSignificant differences were found in social visual preference and cortical morphometry between the two groups. Decreased percentage of fixation time in digital social images (%DSI) was negatively related to not only the thickness of the left fusiform gyrus (FG) and right insula, but also the Calibrated Severity Scores for the Autism Diagnostic Observation Schedule-Social Affect (ADOS-SA-CSS). Mediation analysis showed that %DSI partially mediated the relationship between neuroanatomical alterations (specifically, thickness of the left FG and right insula) and symptom severity.ConclusionThese findings offer initial evidence that atypical neuroanatomical alterations may not only result in direct effects on symptom severity but also lead to indirect effects on symptom severity through social visual preference. This finding enhances our understanding of the multiple neural mechanisms implicated in ASD

    The presence of autoantibodies is associated with improved overall survival in lung cancer patients

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    ObjectiveAutoantibodies have been reported to be associated with cancers. As a biomarker, autoantibodies have been widely used in the early screening of lung cancer. However, the correlation between autoantibodies and the prognosis of lung cancer patients is poorly understood, especially in the Asian population. This retrospective study investigated the association between the presence of autoantibodies and outcomes in patients with lung cancer.MethodsA total of 264 patients diagnosed with lung cancer were tested for autoantibodies in Henan Provincial People’s Hospital from January 2017 to June 2022. The general clinical data of these patients were collected, and after screening out those who met the exclusion criteria, 151 patients were finally included in the study. The Cox proportional hazards model was used to analyze the effect of autoantibodies on the outcomes of patients with lung cancer. The Kaplan-Meier curve was used to analyze the relationship between autoantibodies and the overall survival of patients with lung cancer.ResultsCompared to lung cancer patients without autoantibodies, those with autoantibodies had an associated reduced risk of death (HRs: 0.45, 95% CIs 0.27~0.77), independent of gender, age, smoking history, pathological type, and pathological stage of lung cancer. Additionally, the association was found to be more significant by subgroup analysis in male patients, younger patients, and patients with small cell lung cancer. Furthermore, lung cancer patients with autoantibodies had significantly longer survival time than those without autoantibodies.ConclusionThe presence of autoantibodies is an independent indicator of good prognosis in patients with lung cancer, providing a new biomarker for prognostic evaluation in patients with lung cancer

    Multimodal Investigation to Understand the Role of Metabolic Dysregulations at the Electrode-Tissue Interface

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    Intracortical microelectrodes that can be implanted in the brain have demonstrated significant potential for advancing research in the field of neuroscience and restoring functional outcomes in clinical settings. However, the stability and sensitivity of these intracortical microelectrodes tend to decrease gradually during long-term implantation, ultimately leading to the loss of neuronal signal detection and device implantation failure. Biological reactions have been considered as a critical failure mechanism of the long-term device implantation. The brain’s immune responses to microelectrode implantation that microglia activation and astrocyte reactivity for neuroinflammation are traditionally considered to contribute to loss of neuronal sources for microelectrode signal detection. However, recent evidence reveals a discrepancy between the minimal microglia activation and poor device performances, suggesting other factors may contribute to the chronic decline of signal quality, such as impaired neural network connectivity and metabolic dysregulation in brain tissue near the chronically implanted microelectrode. In this dissertation, we employ in vivo two-photon microscopy, post-mortem immunohistology, and electrophysiology to provide novel insights into the biological reactions that contribute to chronic performance decline of implanted intracortical microelectrodes. We demonstrate that the functional network connectivity is altered within and across different laminar circuits near the chronic implanted microelectrodes. We also reveal how metabolic activity at local brain tissue near the implanted microelectrode is disrupted. The autophagy-lysosomal activity responsible for intracellular waste removal is impaired during the chronic implantation period. We also demonstrate that oligodendrocytes and myelin, which deliver metabolites to neurons, undergo progressive degeneration near the implanted microelectrode over time. Lastly, we present evidence that pharmacological treatments promoting oligodendrocyte density and myelination can rescue malfunctions in network connectivity and enhance the survival of both excitatory and inhibitory neurons. Collectively, these studies offer multiple new perspectives towards a more comprehensive understanding of the biological reactions at electrode-tissue interfaces, which will aid in designing therapeutic treatments for improving the chronic device performance of microelectrodes and developing the next generation of neural interfacing devices

    A Bayesian hierarchical approach to dual response surface modelling

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    In modern quality engineering, dual response surface methodology is a powerful tool to model an industrial process by using both the mean and the standard deviation of the measurements as the responses. The least squares method in regression is often used to estimate the coefficients in the mean and standard deviation models, and various decision criteria are proposed by researchers to find the optimal conditions. Based on the inherent hierarchical structure of the dual response problems, we propose a Bayesian hierarchical approach to model dual response surfaces. Such an approach is compared with two frequentist least squares methods by using two real data sets and simulated data.
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