This work investigated the influencing factors on the stability of direct methanol fuel cells via testing a single‐cell, which was conducted at 60 °C under 100 mA cm−2 for 3,009 h. To completely ...uncover and interpret the performance degradation mechanism, electrochemical method (such as polarization curve, electrochemical impedance spectra, anode polarization voltammetry, methanol crossover and cyclic voltammetry tests), electron microscopy technique (SEM, TEM and EDX) and XRD spectroscopy were coherently performed in this work. The degradation rate in the whole test process is relatively steady, in which the cell voltage decreases 29% and the maximum power density decreases 35%. However, there is obviously an irreversible degradation when the cell runs at about 1,600 h. According to our analysis, the irreversible degradation of the cell is mainly caused by the increase of resistance and decrease of catalytic activity. Further, the increase of the resistance might be due to the increase of the interface resistance between cathode and Nafion® membrane according to SEM results. In addition, the decrease of catalytic activity is mostly caused by Ru loss from anode side to cathode side and the agglomeration of catalyst particles in both electrodes.
We examine the stability of the ‘coast’ motion of fish, that is to say, the motion of a neutrally buoyant fish at constant speed in a straight line. The forces and moments acting on the fish body are ...thus perfectly balanced. The fish motion is said to be unstable if a perturbation in the conditions surrounding the fish results in forces and moments that tend to increase the perturbation, and it is stable if these emerging forces tend to reduce the perturbation and return the fish to its original state. Stability may be achieved actively or passively. Active stabilization requires neurological control that activates musculo-skeletal components to compensate for the external perturbations acting against stability. Passive stabilization on the other hand requires no energy input by the fish and is dependent upon the fish morphology, i.e. geometry and elastic properties. In this paper, we use a deformable body consisting of an articulated body equipped with torsional springs at its hinge joints and submerged in an unbounded perfect fluid as a simple model to study passive stability as a function of the body geometry and spring stiffness. We show that for given body dimensions, the spring elasticity, when properly chosen, leads to passive stabilization of the (otherwise unstable) coast motion.
Through regulating target genes via the mechanisms of posttranscriptional cleavage or translational repression,plant miRNAs involve diverse biological processes associating with plant ...growth,development,and abiotic stress responses.In this study,we functionally characterized TaMIR1119,a miRNA family member of wheat (Triticum aestivum),in regulating the drought adaptive response of plants.TaMIR1119 putatively targets six genes categorized into the functional classes of transcriptional regulation,RNA and biochemical metabolism,trafficking,and oxidative stress defense.Upon simulated drought stress,the TaMIR1119 transcripts abundance in roots was drastically altered,showing to be upregulated gradually within a 48-h drought regime and that the drought-induced transcripts were gradually restored along with a 48-h recovery treatment.In contrast,most miRNA target genes displayed reverse expression patterns to TaMIR1119,exhibiting a downregulated expression pattern upon drought and whose reduced transcripts were re-elevated along with a normal recovery treatment.These expression analysis results indicated that TaMIR1119 responds to drought and regulates the target genes mainly through a cleavage mechanism.Under drought stress,the tobacco lines with TaMIR1119 overexpression behaved improved phenotypes,showing increased plant biomass,photosynthetic parameters,osmolyte accumulation,and enhanced antioxidant enzyme (AE) activities relative to wild type.Three AE genes,NtFeSOD,NtCAT1;3,and NtSOD2;1,encoding superoxide dismutase (SOD),catalase (CAT),and peroxidase (POD) proteins,respectively,showed upregulated expression in TaMIR1119 overexpression lines,suggesting that they are involved in the regulation of AE activities and contribution to the improved cellular reactive oxygen species (ROS) homeostasis in drought-challenged transgenic lines.Our results indicate that TaMIR1119 plays critical roles in regulating plant drought tolerance through transcriptionally regulating the target genes that modulate osmolyte accumulation,photosynthetic function,and improve cellular ROS homeostasis of plants.
To systemically assess the clinical efficacy of oral Chinese patent medicine for migraine by using network Meta-analysis. Four Chinese databases(CNKI, VIP, WanFang, CBM), three English ...databases(Medline, EMbase, Cochrane Library) and ClinicalTrials.gov were systematically and comprehensively retrieved from the establishment of each database to April 24, 2020. Rando-mized controlled trial(RCT) on oral Chinese patent medicine combined with Flunarizine for migraine were screened out according to inclusion criteria and exclusion criteria. Literature screening and data extraction were conducted independently by 2 researchers. The included studies were evaluated with the Cochrane bias risk assessment tool. Data analysis was conducted by using Stata 16.0 software. Finally, a total of 52 RCTs were included, involving 11 kinds of oral Chinese patent medicines. The results of the network Meta-analysis showed that in terms of headache frequency, the order of efficacy was: Flunarizine combined with Tongtian Oral Liquid>c
In this study, common prescriptions were retrieved from existing data in multiple ways to determine the selection principle of common formulas in traditional Chinese medicine(TCM) clinical practice ...guidelines. Taking the selection of common prescriptions in the clinical practice guidelines of TCM for migraine as an example, we searched common prescriptions for migraines from National Essential Medicine List, the National Drug Catalog for Basic Medical Insurance, Work-related Injury Insurance, and Maternity Insurance, Chinese Pharmacopoeia, three teaching materials and two clinical practice guidelines, and we also electronically searched CNKI, VIP, WanFang about famous clinical experience for migraine published from 1990 to 2019. At the same time, 32 prescriptions commonly used by experts in the clinical questionnaire survey were collected to summarize and analyze the TCM clinically applicable syndrome types and medication rules of the included prescriptions and medicines. From the National Essential Medicine
The present clinical practice guideline was written by experts organized by the special group of key projects in the 13 th five-year plan period of the China Academy of Chinese Medical Sciences based ...on the standards and procedures of World Health Orga-nization Handbook for Guideline Development, with "evidence-based, consensus-based, and experience-based principle" as a guide. On the basis of practice in traditional Chinese medicine(TCM) and clinical research for migraine, following the idea and method of evidence-based medicine, as well as the expert experience, the current best evidence and patients' values, the internationally recognized evidence quality evaluation methods and recommendation grading system were combined with the prescription record of classical TCM, TCM expert experience, and modern clinical research evidences. The acupuncture therapy, classic prescriptions and Chinese patent medicines used in the treatment of migraine in acute stage and preventive treatment were summarized to obtain five
Due to the large degree of ionization of the sputtered flux and high quality film fabrication, high power pulsed magnetron sputtering (HPPMS) is widely used. However, compared with DC sputtering, low ...deposition rate is probably the drawback of the HPPMS technique and restricts its application. In order to increase the deposition rate of HPPMS, different combinations of frequency and pulse width at a constant duty cycle were used to modulate the deposition rate of the Ti film. The results showed that wider pulse width would be more effective than increasing frequency on improving titanium deposition rate for a constant duty cycle. The pulse width also would affect the power utilization ratio. Especially for a high duty cycle of 4.8% and 5.6%, a wider pulse was favorable to make full use of power on film deposition, resulting in a higher normalized static deposition rate. Meanwhile, with increase in pulse width for a constant duty cycle, adatom mobility and the deposition rate increased, contributing to growth of crystallite size and higher surface roughness of Ti thin films.
•Modulate the deposition rate through changing the combination of frequency and pulse width.•Wider pulse width is beneficial for improving deposition rate at a constant duty cycle.•Wider pulse width induces to the higher normalized static deposition rate at a constant duty cycle.
To investigate the efficacy of haplotype hematopoietic stem cell transplantation in the treatment of acquired severe aplastic anemia (SAA) in children.
The clinical characteristics of 59 pediatric ...patients with SAA, including 26 cases VSAA, 37males and 22 females, 47 cases typeⅠ and 12 cases typeⅡ, undrerwent haplo-HSCT in our hospital between December 1
, 2011 and December 1
, 2017 were retrospectively analyzed. Among 59 patients, 56 patients with a median age of 4.5 (1.2-14.8) years and median weight of 43 (12-80) kg underwent their first HSCT and 3 patients underwent their second HSCT. All patients received the following conditioning regimen: busulfan, cyclophosphamide, and rabbit ATG or Bu (-, CTX) , fludarabineand rabbit ATG. The prophylaxis of acute graft versus host disease (aGVHD) was cyclosporine (CsA) , MMF and methotrexate. All patients received bone marrow transfusion on day 01 and peripheral stem cell transfusion on day 02 from haploid donor. The median dose of donor mononuclear cell counts was 1
Microorganisms vary in both biomass and diversity composition along glacial depth profiles. However, it is not well known about the major processes controlling the structure diversity shift of ...microorganisms in a glacier, although, aeolian deposition has been widely accepted as one mechanism regulating the distribution of microorganisms in snow. To better understand the distribution of microorganisms in a glacier, variations in bacterial diversity and biomass along a pit profile from the Kuytun 51 Glacier in the Tianshan Mountains in China were investigated by using 16S rRNA gene library sequencing and flow cytometric analysis with cell sorting markers. Four clone libraries were established from each of the different sampling depths from the snow pit. A total of 311 insert clones were preliminarily screened by HaeIII‐based amplified rRNA restriction analysis (ARDRA), and 83 representatives of the unique ARDRA patterns were sequenced. Sequence analysis showed that the bacteria in the snow pit were affiliated with 23 known subphyla within the members of the Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, and Cyanobacteria phyla. To examine diversity shifts in snow, the diversity structures from the snow pit were also compared with those previously recovered from the different habitats along the Kuytun 51 Glacier surface and from the deep Malan Glacier. The results showed structure shift patterns in bacterial diversity among the surface, deep snow, and deep ice. Sequence analysis displayed a dramatic diversity shift from a mixture of Cyanobacteria and other eubacteria across the glacial surface to other eubacteria without Cyanobacteria in the deep snow. However, the biogeochemical analyses showed great variability in the measured abiotic and biotic components along the pit profile, which reinforced the idea of aeolian deposition being a dominant mechanism controlling the size and diversity of microorganisms in snow. Overall, the findings indicated a significant bacterial diversity shift between the surface and deep snow, confirming our hypothesis of a postdeposition influence on the microbial diversity structures in the glacier.
Surface modification with high-power glow discharges is a promising physical vapor deposition (PVD) technology for industrial usage. A metal ion density higher than 1018 m−3 can be obtained due to a ...high-power input in the plasma. In the present paper, titanium films were deposited on Si (100) substrates using high-power impulse magnetron sputtering (HIPIMS). The pulse duration was varied to investigate the deposition rate and the titanium film structure. The plasma source was an unbalanced magnetron sputtering (UBMS) discharge generation system. The deposition rate was correlated to the electrical characteristics. There was an instantaneous power threshold of approximately 36 kW to significantly increase the deposition rate by 4–5 times. The deposition rate increased linearly with respect to the average power until the average power reached 5.6 kW (about 30 W/cm2 for a total area of the target), and an 83% increase of the deposition rate from the linear relationship was observed. The increase of the deposition rate was possibly closely related to the so-called thermal spike, where the target temperature increases due to a high power input to the target. The surface morphology and the crystalline structure of the films were studied for a variety of pulse durations, and the results were compared to the case of the direct-current magnetron sputtering (dcMS) process. The titanium films at an average power of 1.2 kW and a pulse duration of 50 μs have a smaller crystalline size and a smoother surface than those at an average power of 825 W by dcMS. The crystal orientation (101) was dominated when the pulse duration was lengthened to 180 μs, although the (002) orientation was dominant in dcMS. The crystal size and the surface roughness increased significantly when the pulse duration was increased from 50 μs to 180 μs in HIPIMS. The consumed power in the plasma by HIPIMS can be an important parameter for the crystal size and the structure.
► Ti film preparation using HIPIMS. ► The pulse duration was varied to investigate the condition of a high deposition rate, comparing with the case of the direct-current magnetron sputtering (dcMS) process. ► The abrupt increment of the deposition rate by a thermal spike.
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