Several recent studies have shown the presence of genes for the key enzyme associated with archaeal methane/alkane metabolism, methyl-coenzyme M reductase (Mcr), in metagenome-assembled genomes (MAGs) divergent to existing archaeal lineages. Here, we study the mcr-containing archaeal MAGs from several hot springs, which reveal further expansion in the diversity of archaeal organisms performing methane/alkane metabolism. Significantly, an MAG basal to organisms from the phylum Thaumarchaeota that contains mcr genes, but not those for ammonia oxidation or aerobic metabolism, is identified. Together, our phylogenetic analyses and ancestral state reconstructions suggest a mostly vertical evolution of mcrABG genes among methanogens and methanotrophs, along with frequent horizontal gene transfer of mcr genes between alkanotrophs. Analysis of all mcr-containing archaeal MAGs/genomes suggests a hydrothermal origin for these microorganisms based on optimal growth temperature predictions. These results also suggest methane/alkane oxidation or methanogenesis at high temperature likely existed in a common archaeal ancestor.
In this study, a new type of field-effect transistor (FET)-based biosensor is demonstrated to be able to overcome the problem of severe charge-screening effect caused by high ionic strength in solution and detect proteins in physiological environment. Antibody or aptamer-immobilized AlGaN/GaN high electron mobility transistors (HEMTs) are used to directly detect proteins, including HIV-1 RT, CEA, NT-proBNP and CRP, in 1X PBS (with 1%BSA) or human sera. The samples do not need any dilution or washing process to reduce the ionic strength. The sensor shows high sensitivity and the detection takes only 5 minutes. The designs of the sensor, the methodology of the measurement, and the working mechanism of the sensor are discussed and investigated. A theoretical model is proposed based on the finding of the experiments. This sensor is promising for point-of-care, home healthcare, and mobile diagnostic device.Field-effect transistors (FETs) attract great interest for biomolecular detection, due to their high sensitivity, small size, and label-free detection, which are suitable for point-of-care or personal homecare devices. Either planar or nanowire FET-based biosensors have been widely studied using various materials, such as Si 1 , GaN 2 , carbon nanotube (CNT) 3 , or graphene oxide 4 . Conventionally, FET-based biosensors with receptors (ex. antibody) immobilized on the gate region above the active channel of the FETs face an intrinsic issue, which is the severe charge screening effect in high ionic strength solutions, such as in serum or blood samples, leading to low sensitivity for direct detection of protein in the physiological environment. The Debye length in physiological salt environment (1X PBS) is near 0.7 nm, which is much smaller than the size of a regular IgG antibody (5~10 nm) 5 . In order to effectively detect proteins with receptor-immobilized FETs, the electrical measurements are usually conducted in diluted buffer solutions, such as in 0.1X PBS or 0.01X PBS, where the Debye lengths as 2.4 nm and 7.4 nm, respectively 1,6,7 . However, diluted ionic strength solution may cause the change in protein structure, resulting in the loss of protein activity, and the binding affinity as well. For most biological reactions, which occur in physiological high salt environment, a biosensor that can be used directly with physiological samples is much favored. Besides, an additional washing process is needed for conventional FET-based biosensors to remove the unbound antigen before electrical measurement, which also increases the complexity of the whole sensor system. Therefore, direct detection of the target protein in physiological sample is very demanding.Previously, several groups have reported that conventional FET-based biosensors can effectively detect proteins in physiological salt environment, using alternative current (AC) signals in drain-source voltage (V ds ), in conjunction with a reference electrode, in a relatively high frequency [8][9][10][11] . The better sensitivity of AC signals compared to that o...
This survey-based research study explores the influence of managerial coaching behavior on relationships between organizational investments in social capital (OISC) and employee work-related performance. The results obtained from a survey of 408 employees from multiple organizations across a wide range of industries indicate that OISC are positively related to employee job performance, commitment to service quality, and organizational citizenship behavior. However, the results from sub-group analyses also indicate that these relationships are stronger at low to moderate levels of managerial coaching suggesting that selective rather than exhaustive application of the developmental approach may be more effective. Theoretical and practical implications of these somewhat unexpected findings are developed.
Purpose -The purpose of this paper is to examine the antecedents of, and the relationships between, entrepreneurial opportunity recognition, and individual-level innovation performance. Design/methodology/approach -Questionnaire data were collected from 268 senior R&D project team members (response rate 64.58 percent) along with 83 R&D managers who evaluated their employees' innovative behaviors in one science park in Taiwan. Findings -The results show that an individual's self-efficacy, prior knowledge, social networks, and perception about the industrial environment on opportunities all had positive effects on entrepreneurial opportunity recognition. Also entrepreneurial opportunity recognition contributed significantly to individual-level innovation performance.Research limitations/implications -The findings show that perception about the industrial environment on opportunities variable was the most important predictor among all four of the antecedents of entrepreneurial opportunity recognition. That is, individual characteristics and traits cannot fully explain the entrepreneurial opportunity recognition process. Because the data were limited to high technology industry, future studies need to validate these findings in other industries. Practical implications -Findings of this study suggest that to increase R&D employee's innovation performance, it is critical for high technology firms to invest in developing and enhancing employees' entrepreneurial opportunity recognition ability. Originality/value -The process of entrepreneurial opportunity recognition has been viewed as a black box. Although the literature has explored various antecedents that influence entrepreneurial opportunity recognition, there is limited empirical research that has examined the linkage between entrepreneurial opportunity recognition and potential outcome variables.
The treatment of choice for Stenotrophomonas maltophilia is trimethoprim-sulfamethoxazole (SXT). Fluoroquinolones (FQs) have in vitro activity against S. maltophilia; however, there is limited published information on their effectiveness. The purpose of this study is to compare the effectiveness of FQs and SXT for the treatment of S. maltophilia. A retrospective review of 98 patients with S. maltophilia infections who received SXT or FQ monotherapy was conducted. Patients >18 years old with a positive culture for S. maltophilia and clinical signs of infection who received treatment for >48 h were included. Microbiological cure and clinical response were evaluated at the end of therapy (EOT). In-hospital mortality and isolation of nonsusceptible isolates were also evaluated. Thirty-five patients received SXT, and 63 patients received FQ; 48 patients received levofloxacin, and 15 patients received ciprofloxacin. The most common infection was pulmonary. The overall microbiological cure rate at EOT was 63%. Thirteen of 20 patients (65%) who received SXT and 23 of 37 patients (62%) who received FQ had microbiological cure at EOT (P ؍ 0.832). The overall clinical success rate was 55%, 52% for those who received FQ and 61% for those who received SXT (P ؍ 0.451). In-hospital mortality was 24%, with similar rates in the two groups (25% for FQ versus 22% for SXT; P ؍ 0.546). Development of resistance on repeat culture was 30% for FQ and 20% for SXT (P ؍ 0.426). Fluoroquinolone and SXT monotherapies may be equally effective for the treatment of S. maltophilia infections. Resistance was documented in subsequent isolates of S. maltophilia in both groups.
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