1,737 research outputs found

    Noninvasive prediction of Blood Lactate through a machine learning-based approach.

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    We hypothesized that blood lactate concentration([Lac]blood) is a function of cardiopulmonary variables, exercise intensity and some anthropometric elements during aerobic exercise. This investigation aimed to establish a mathematical model to estimate [Lac]blood noninvasively during constant work rate (CWR) exercise of various intensities. 31 healthy participants were recruited and each underwent 4 cardiopulmonary exercise tests: one incremental and three CWR tests (low: 35% of peak work rate for 15 min, moderate: 60% 10 min and high: 90% 4 min). At the end of each CWR test, venous blood was sampled to determine [Lac]blood. 31 trios of CWR tests were employed to construct the mathematical model, which utilized exponential regression combined with Taylor expansion. Good fitting was achieved when the conditions of low and moderate intensity were put in one model; high-intensity in another. Standard deviation of fitting error in the former condition is 0.52; in the latter is 1.82 mmol/liter. Weighting analysis demonstrated that, besides heart rate, respiratory variables are required in the estimation of [Lac]blood in the model of low/moderate intensity. In conclusion, by measuring noninvasive cardio-respiratory parameters, [Lac]blood during CWR exercise can be determined with good accuracy. This should have application in endurance training and future exercise industry

    Enhancing speed of pinning synchronizability: low-degree nodes with high feedback gains

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    Controlling complex networks is of paramount importance in science and engineering. Despite recent efforts to improve controllability and synchronous strength, little attention has been paid to the speed of pinning synchronizability (rate of convergence in pinning control) and the corresponding pinning node selection. To address this issue, we propose a hypothesis to restrict the control cost, then build a linear matrix inequality related to the speed of pinning controllability. By solving the inequality, we obtain both the speed of pinning controllability and optimal control strength (feedback gains in pinning control) for all nodes. Interestingly, some low-degree nodes are able to achieve large feedback gains, which suggests that they have high influence on controlling system. In addition, when choosing nodes with high feedback gains as pinning nodes, the controlling speed of real systems is remarkably enhanced compared to that of traditional large-degree and large-betweenness selections. Thus, the proposed approach provides a novel way to investigate the speed of pinning controllability and can evoke other effective heuristic pinning node selections for large-scale systems

    Rapid label-free identification of mixed bacterial infections by surface plasmon resonance

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    <p>Abstract</p> <p>Background</p> <p>Early detection of mixed aerobic-anaerobic infection has been a challenge in clinical practice due to the phenotypic changes in complex environments. Surface plasmon resonance (SPR) biosensor is widely used to detect DNA-DNA interaction and offers a sensitive and label-free approach in DNA research.</p> <p>Methods</p> <p>In this study, we developed a single-stranded DNA (ssDNA) amplification technique and modified the traditional SPR detection system for rapid and simultaneous detection of mixed infections of four pathogenic microorganisms (<it>Pseudomonas aeruginosa</it>, <it>Staphylococcus aureus</it>, <it>Clostridium tetani </it>and <it>Clostridium perfringens</it>).</p> <p>Results</p> <p>We constructed the circulation detection well to increase the sensitivity and the tandem probe arrays to reduce the non-specific hybridization. The use of 16S rDNA universal primers ensured the amplification of four target nucleic acid sequences simultaneously, and further electrophoresis and sequencing confirmed the high efficiency of this amplification method. No significant signals were detected during the single-base mismatch or non-specific probe hybridization (<it>P </it>< 0.05). The calibration curves of amplification products of four bacteria had good linearity from 0.1 nM to 100 nM, with all R<sup>2 </sup>values of >0.99. The lowest detection limits were 0.03 nM for <it>P. aeruginosa</it>, 0.02 nM for <it>S. aureus</it>, 0.01 nM for <it>C. tetani </it>and 0.02 nM for <it>C. perfringens</it>. The SPR biosensor had the same detection rate as the traditional culture method (<it>P </it>< 0.05). In addition, the quantification of PCR products can be completed within 15 min, and excellent regeneration greatly reduces the cost for detection.</p> <p>Conclusions</p> <p>Our method can rapidly and accurately identify the mixed aerobic-anaerobic infection, providing a reliable alternative to bacterial culture for rapid bacteria detection.</p

    Task-Dependent Differences in Operant Behaviors of Rats With Acute Exposure to High Ambient Temperature: A Potential Role of Hippocampal Dopamine Reuptake Transporters

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    Behavioral or cognitive functions are known to be influenced by thermal stress from the change in ambient temperature (Ta). However, little is known about how increased Ta (i.e., when the weather becomes warm or hot) may affect operant conditioned behavior and the neural substrates involved. The present study thus investigated the effects of high Ta on operant behaviors maintained on a fixed-ratio 1 (FR1) and a differential reinforcement for low-rate responding 10 s (DRL 10-s) schedule of reinforcement. The rats were randomly assigned to three groups receiving acute exposure to Ta of 23°C, 28°C, and 35°C, respectively, for evaluating the effects of high Ta exposure on four behavioral tests. Behavioral responses in an elevated T-maze and locomotor activity were not affected by Ta treatment. Regarding operant tests, while the total responses of FR1 behavior were decreased only under 35°C when compared with the control group of 23°C, those of DRL 10-s behavior were significantly reduced in both groups of 28°C and 35°C. Distinct patterns of inter-response time (IRT) distribution of DRL behavior appeared among the three groups; between-group differences of behavioral changes produced by high Ta exposure were confirmed by quantitative analyses of IRT data. Western blot assays of dopamine (DA) D1 and D2 receptor, DA transporter (DAT) and brain-derived neurotrophic factor (BDNF) were conducted for the sample tissues collected in six brain areas from all the subjects after acute high Ta exposure. Significant Ta-related effects were only revealed in the dorsal hippocampus (dHIP). In which, the DAT levels were increased in a Ta-dependent fashion that was associated with operant behavior changes under high Ta exposure. And, there as an increased level of D1 receptors in the 28°C group. In summary, these data indicate that the performance of operant behavior affected by the present high Ta exposure is task-dependent, and these changes of operant behaviors cannot be attributed to gross motor function or anxiety being affected. The regulation of dHIP DAT may be involved in this operant behavioral change under high Ta exposure

    Complete chloroplast genome of Oncidium Gower Ramsey and evaluation of molecular markers for identification and breeding in Oncidiinae

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    <p>Abstract</p> <p>Background</p> <p><it>Oncidium </it>spp. produce commercially important orchid cut flowers. However, they are amenable to intergeneric and inter-specific crossing making phylogenetic identification very difficult. Molecular markers derived from the chloroplast genome can provide useful tools for phylogenetic resolution.</p> <p>Results</p> <p>The complete chloroplast genome of the economically important <it>Oncidium </it>variety <it>Onc</it>. Gower Ramsey (Accession no. GQ324949) was determined using a polymerase chain reaction (PCR) and Sanger based ABI sequencing. The length of the <it>Oncidium </it>chloroplast genome is 146,484 bp. Genome structure, gene order and orientation are similar to <it>Phalaenopsis</it>, but differ from typical Poaceae, other monocots for which there are several published chloroplast (cp) genome. The <it>Onc</it>. Gower Ramsey chloroplast-encoded <it>NADH dehydrogenase </it>(<it>ndh</it>) genes, except <it>ndhE</it>, lack apparent functions. Deletion and other types of mutations were also found in the <it>ndh </it>genes of 15 other economically important Oncidiinae varieties, except <it>ndhE </it>in some species. The positions of some species in the evolution and taxonomy of Oncidiinae are difficult to identify. To identify the relationships between the 15 Oncidiinae hybrids, eight regions of the <it>Onc</it>. Gower Ramsey chloroplast genome were amplified by PCR for phylogenetic analysis. A total of 7042 bp derived from the eight regions could identify the relationships at the species level, which were supported by high bootstrap values. One particular 1846 bp region, derived from two PCR products (<it>trnH</it><sup>GUG </sup>-<it>psbA </it>and <it>trnF</it><sup>GAA</sup>-<it>ndhJ</it>) was adequate for correct phylogenetic placement of 13 of the 15 varieties (with the exception of <it>Degarmoara </it>Flying High and <it>Odontoglossum </it>Violetta von Holm). Thus the chloroplast genome provides a useful molecular marker for species identifications.</p> <p>Conclusion</p> <p>In this report, we used <it>Phalaenopsis. aphrodite </it>as a prototype for primer design to complete the <it>Onc</it>. Gower Ramsey genome sequence. Gene annotation showed that most of the <it>ndh </it>genes inOncidiinae, with the exception of <it>ndhE</it>, are non-functional. This phenomenon was observed in all of the Oncidiinae species tested. The genes and chloroplast DNA regions that would be the most useful for phylogenetic analysis were determined to be the <it>trnH</it><sup>GUG</sup>-<it>psbA </it>and the <it>trnF</it><sup>GAA</sup>-<it>ndhJ </it>regions. We conclude that complete chloroplast genome information is useful for plant phylogenetic and evolutionary studies in <it>Oncidium </it>with applications for breeding and variety identification.</p

    Enhanced Antifungal Bioactivity of Coptis Rhizome Prepared by Ultrafining Technology

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    The aim of this study was to identify and quantify the bioactive constituents in the methanol extracts of Coptis Rhizome prepared by ultrafining technology. The indicator compound was identified by spectroscopic method and its purity was determined by HPLC. Moreover, the crude extracts and indicator compound were examined for their ability to inhibit the growth of Rhizoctonia solani KĂĽhn AG-4 on potato dextrose agar plates. The indicator compound is a potential candidate as a new plant derived pesticide to control Rhizoctonia damping-off in vegetable seedlings. In addition, the extracts of Coptis Rhizome prepared by ultrafining technology displayed higher contents of indicator compound; they not only improve their bioactivity but also reduce the amount of the pharmaceuticals required and, thereby, decrease the environmental degradation associated with the harvesting of the raw products

    Highly Prevalent Multidrug-Resistant Salmonella From Chicken and Pork Meat at Retail Markets in Guangdong, China

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    This study aimed to investigate the prevalence, serotype distribution, and antibiotic resistance, and to characterize the extended spectrum β-lactamases (ESBLs) producing Salmonella isolates from chicken and pork meats from retail markets in Guangdong province, China. A total of 903 retail meat samples (475 chicken and 428 pork meats) were obtained from six cities (Guangzhou, Shenzhen, Heyuan, Shaoguan, Foshan, and Yunfu) of Guangdong province between May 2016 and April 2017. High levels of Salmonella contamination were detected in chicken (302/475, 63.6%) and pork (313/428, 73.1%). Thirty-eight serotypes were identified in 615 detected Salmonella, and the serotypes varied greatly between chicken and pork samples. Agona (55/302, 18.2%), Corvallis (45/302, 14.9%), Kentucky (38/302, 12.6%), Mbandaka (32/302, 10.6%) was the dominant serotypes in chicken samples. However, Typhimurium (78/313, 24.9%), Rissen (67/313, 24.1%), Derby (66/313, 21.1%), and London (48, 15.3%) were the most common in pork samples. High rates of antibiotic resistance were found to sulfisoxazole (468/615, 76.1%), tetracycline (463/615, 75.3%), ampicillin (295/615, 48.0%), and ofloxacin (275/615, 44.7%). Notably, antimicrobial susceptibility tests identified resistance to polymyxin B (12/615, 2.0%) and imipenem (3/615, 0.5%). Multidrug-resistance (MDR) was detected in Salmonella isolated from chicken (245/302, 81.1%) and pork (229/313, 73.2%). The resistance rate of different Salmonella serotypes varied widely. Especially, isolates such as Typhimurium, Agona, Corvallis and Kentucky exhibited highly resistance to antibiotics. The MDR rate of Salmonella isolates from chicken was significantly higher than that from pork isolates (P &lt; 0.05). Twenty-one Salmonella isolates were identified as ESBLs-producing, covering six Salmonella serotypes and displaying different pulse field gel electrophoresis (PFGE) genotypes. BlaOXA-1 was the dominant ESBLs gene (9/21, 42.9%), followed by blaCTX-M-55 (5/21, 23.8%). This study indicated that Salmonella was widespread in chicken and pork from retail markets in Guangdong province and the isolates showed high multidrug-resistance, especially the known multidrug-resistant Salmonella serotypes. Therefore, it is important to focus on Salmonella serotypes and strengthen the long-term monitoring of MDR Salmonella serotypes in animal-derived foods
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