273 research outputs found
Structure Sensitivity in Oxide Catalysis: First-Principles Kinetic Monte Carlo Simulations for CO Oxidation at RuO(111)
We present a density-functional theory based kinetic Monte Carlo study of CO
oxidation at the (111) facet of RuO. We compare the detailed insight into
elementary processes, steady-state surface coverages and catalytic activity to
equivalent published simulation data for the frequently studied RuO(110)
facet. Qualitative differences are identified in virtually every aspect ranging
from binding energetics over lateral interactions to the interplay of
elementary processes at the different active sites. Nevertheless, particularly
at technologically relevant elevated temperatures, near-ambient pressures and
near-stoichiometric feeds both facets exhibit almost identical catalytic
activity. These findings challenge the traditional definition of structure
sensitivity based on macroscopically observable turnover frequencies and allow
to scrutinize the applicability of structure sensitivity classifications
developed for metals to oxide catalysis.Comment: 15 pages, 5 figure
Recommended from our members
COVID-19 infection: the China and Italy perspectives.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. Since its first report in December 2019, despite great efforts made in almost every country worldwide, this disease continues to spread globally, especially in most parts of Europe, Iran, and the United States. Here, we update the recent understanding in clinical characteristics, diagnosis strategies, as well as clinical management of COVID-19 in China as compared to Italy, with the purpose to integrate the China experience with the global efforts to outline references for prevention, basic research, treatment as well as final control of the disease. Being the first two countries we feel appropriate to evaluate the evolution of the disease as well as the early result of the treatment, in order to offer a different baseline to other countries. It is also interesting to compare two countries, with a very significant difference in population, where the morbidity and mortality has been so different, and unrelated to the size of the country
Electroacupuncture Reduces Postoperative Pain and Analgesic Consumption in Patients Undergoing Thoracic Surgery: A Randomized Study
The aim of this study was to evaluate the effect of electroacupuncture (EA) on postoperative pain management in patients undergoing thoracic surgery. A randomized study was conducted. Ninety-two thoracic surgical patients were randomly divided into an EA group and a sham group. Postoperative intravenous analgesia was applied with a half dose of the conventional drug concentration in both groups. In the EA group, EA treatment was administered for three consecutive days after the surgery with 6 sessions of 30βmin each. Compared with the sham group, patients in the EA group had a lower visual analogue scale (VAS) score at 2, 24, 48, and 72 hours and consumed less analgesic after surgery. The incidence of opioid-related adverse effects of nausea was lower in the EA group. The time to first flatus and defecation was also shorter in the EA group. Furthermore, the plasma Ξ²-endorphin (Ξ²-EP) level was higher by radioimmunoassay and the plasma 5-hydroxytryptamine (5-HT) level was lower in the EA group by enzyme-linked immunosorbent assay during the first 72βhr after thoracic surgery. Therefore, EA is suitable as an adjunct treatment for postoperative pain management after thoracic surgery
Methylcap-Seq Reveals Novel DNA Methylation Markers for the Diagnosis and Recurrence Prediction of Bladder Cancer in a Chinese Population
PURPOSE: There is a need to supplement or supplant the conventional diagnostic tools, namely, cystoscopy and B-type ultrasound, for bladder cancer (BC). We aimed to identify novel DNA methylation markers for BC through genome-wide profiling of BC cell lines and subsequent methylation-specific PCR (MSP) screening of clinical urine samples. EXPERIMENTAL DESIGN: The methyl-DNA binding domain (MBD) capture technique, methylCap/seq, was performed to screen for specific hypermethylated CpG islands in two BC cell lines (5637 and T24). The top one hundred hypermethylated targets were sequentially screened by MSP in urine samples to gradually narrow the target number and optimize the composition of the diagnostic panel. The diagnostic performance of the obtained panel was evaluated in different clinical scenarios. RESULTS: A total of 1,627 hypermethylated promoter targets in the BC cell lines was identified by Illumina sequencing. The top 104 hypermethylated targets were reduced to eight genes (VAX1, KCNV1, ECEL1, TMEM26, TAL1, PROX1, SLC6A20, and LMX1A) after the urine DNA screening in a small sample size of 8 normal control and 18 BC subjects. Validation in an independent sample of 212 BC patients enabled the optimization of five methylation targets, including VAX1, KCNV1, TAL1, PPOX1, and CFTR, which was obtained in our previous study, for BC diagnosis with a sensitivity and specificity of 88.68% and 87.25%, respectively. In addition, the methylation of VAX1 and LMX1A was found to be associated with BC recurrence. CONCLUSIONS: We identified a promising diagnostic marker panel for early non-invasive detection and subsequent BC surveillance
Optimization of single-mode sapphire waveguide Bragg gratings
We demonstrate the fabrication and optimization of waveguide Bragg gratings on single-crystal sapphire substrates using femtosecond laser direct writing. The gratings are fabricated using modulated bursts and are embedded inside single-mode depressed cladding waveguides. Through design optimization, and fabrication parameter tuning, a depressed cladding waveguide with a loss of βΌ0.8 dB/cm and a Bragg grating with a reflectivity of higher than 90% in the telecommunications wavelength band are demonstrated. The waveguide Bragg grating exhibits stable thermal properties under annealing at 1200Β°C. A sampled grating and a grating array are also demonstrated, showing the potential for more complex grating designs
Epstein-Barr Virus-Associated T-Cell Lymphoproliferative Disorder Presenting as Chronic Diarrhea and Intestinal Bleeding: A Case Report
Systemic Epstein-Barr virus-positive T-cell lymphoproliferative childhood disease (EBV+ T-LPD) is extremely rare. Primary acute or chronic active Epstein-Barr virus infection triggers EBV+ T-LPD's onset and the disease involves clonal proliferation of infected T-cells with activated cytotoxic phenotype. The adult-onset EBV+ T-LPD (ASEBV+ T-LPD) is even rarer and needs to be extensively studied. Further, according to literature review, it is a challenge to find patients who are immunocompetent and diagnosed with ASEBV+ T-LPD involving gastrointestinal tract. This case report discusses a previously healthy middle aged woman who presented with unique symptoms mimicking inflammatory bowel disease, and required a total colectomy and terminal ileum rectomy, as reveled by endoscopic examinations, due to severe gastrointestinal bleeding. Post-surgery histopathological findings were confirmatory for the diagnosis of ASEBV+ T-LPD (II: Borderline). This patient died 7 months after the diagnosis
- β¦