2,184 research outputs found
The application of inelastic neutron scattering to investigate the ‘dry’ reforming of methane over an alumina-supported nickel catalyst operating under conditions where filamentous carbon formation is prevalent
The use of CO2 in reforming methane to produce the industrial feedstock syngas is an economically and environmentally attractive reaction. An alumina-supported nickel catalyst active for this reaction additionally forms filamentous carbon. The catalyst is investigated by inelastic neutron scattering as well as elemental analysis, temperature-programmed oxidation, temperature-programmed hydrogenation, X-ray diffraction, transmission electron microscopy and Raman scattering. Isotopic substitution experiments, using 13CO2 for 12CO2, show the oxidant to contribute to the carbon retention evident with this sample. At steady-state operation, a carbon mass balance of 95 % is observed. A kinetic scheme is proposed to account for the trends observed
Improving Phase Change Memory Performance with Data Content Aware Access
A prominent characteristic of write operation in Phase-Change Memory (PCM) is
that its latency and energy are sensitive to the data to be written as well as
the content that is overwritten. We observe that overwriting unknown memory
content can incur significantly higher latency and energy compared to
overwriting known all-zeros or all-ones content. This is because all-zeros or
all-ones content is overwritten by programming the PCM cells only in one
direction, i.e., using either SET or RESET operations, not both. In this paper,
we propose data content aware PCM writes (DATACON), a new mechanism that
reduces the latency and energy of PCM writes by redirecting these requests to
overwrite memory locations containing all-zeros or all-ones. DATACON operates
in three steps. First, it estimates how much a PCM write access would benefit
from overwriting known content (e.g., all-zeros, or all-ones) by
comprehensively considering the number of set bits in the data to be written,
and the energy-latency trade-offs for SET and RESET operations in PCM. Second,
it translates the write address to a physical address within memory that
contains the best type of content to overwrite, and records this translation in
a table for future accesses. We exploit data access locality in workloads to
minimize the address translation overhead. Third, it re-initializes unused
memory locations with known all-zeros or all-ones content in a manner that does
not interfere with regular read and write accesses. DATACON overwrites unknown
content only when it is absolutely necessary to do so. We evaluate DATACON with
workloads from state-of-the-art machine learning applications, SPEC CPU2017,
and NAS Parallel Benchmarks. Results demonstrate that DATACON significantly
improves system performance and memory system energy consumption compared to
the best of performance-oriented state-of-the-art techniques.Comment: 18 pages, 21 figures, accepted at ACM SIGPLAN International Symposium
on Memory Management (ISMM
Genetic association of the EGR2 gene with bipolar disorder in Korea
The early growth response gene 2 (EGR2) is located at chromosome 10q21, one of the susceptibility loci in bipolar disorder (BD). EGR2 is involved in cognitive function, myelination, and signal transduction related to neuregulin-ErbB receptor, Bcl-2 family proteins, and brain-derived neurotrophic factor. This study investigated the genetic association of the EGR2 gene with BD and schizophrenia (SPR) in Korea. In 946 subjects (350 healthy controls, 352 patients with BD, and 244 with SPR), nine single nucleotide polymorphisms (SNPs) in the EGR2 gene region were genotyped. Five SNPs showed nominally significant allelic associations with BD (rs2295814, rs61865882, rs10995315, rs2297488, and rs2297489), and the positive associations of all except rs2297488 remained significant after multiple testing correction. Linkage disequilibrium structure analysis revealed two haplotype blocks. Among the common identified haplotypes (frequency > 5%), 'T-G-A-C-T (block 1)' and 'A-A-G-C (block 2)' haplotypes were over-represented, while 'C-G-G-T-T (block 1)' haplotype was under-represented in BD. In contrast, no significant associations were found with SPR. Although an extended analysis with a larger sample size or independent replication is required, these findings suggest a genetic association of EGR2 with BD. Combined with a plausible biological function of EGR2, the EGR2 gene is a possible susceptibility gene in BD
In vitro Antibacterial and Morphological Effects of the Urushiol Component of the Sap of the Korean lacquer tree (Rhus vernicifera Stokes) on Helicobacter pylori
Eradication regimens for Helicobacter pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, alternative anti-H. pylori or supportive antimicrobial agents with fewer disadvantages are necessary for the treatment of H. pylori. We investigated the pH-(5.0, 6.0, 7.0, 8.0, 9.0, and 10.0) and concentration (0.032, 0.064, 0.128, 0.256, 0.514, and 1.024 mg/mL)-dependent antibacterial activity of crude urushiol extract from the sap of the Korean lacquer tree (Rhus vernicifera Stokes) against 3 strains (NCTC11637, 69, and 219) of H. pylori by the agar dilution method. In addition, the serial (before incubation, 3, 6, and 10 min after incubation) morphological effects of urushiol on H. pylori were examined by electron microscopy. All strains survived only within pH 6.0-9.0. The minimal inhibitory concentrations of the extract against strains ranged from 0.064 mg/mL to 0.256 mg/mL. Urushiol caused mainly separation of the membrane, vacuolization, and lysis of H. pylori. Interestingly, these changes were observed within 10 min following incubation with the 1×minimal inhibitory concentrations of urushiol. The results of this work suggest that urushiol has potential as a rapid therapeutic against H. pylori infection by disrupting the bacterial cell membrane
Insights into the formation mechanism of two-dimensional lead halide nanostructures
We present a colloidal synthesis strategy for lead halide nanosheets with a thickness of far below 100 nm. Due to the layered structure and the synthesis parameters the crystals of PbI2 are initially composed of many polytypes. We propose a mechanism which gives insight into the chemical process of the PbI2 formation. Further, we found that the crystal structure changes with increasing reaction temperature or by performing the synthesis for longer time periods changing for the final 2H structure. In addition, we demonstrate a route to prepare nanosheets of lead bromide as well as lead chloride in a similar way. Lead halides can be used as a detector material for high-energy photons including gamma and X-rays
Empagliflozin, irrespective of blood pressure, improves outcomes in heart failure with preserved ejection fraction: the EMPEROR-Preserved trial
AIMS: Empagliflozin reduces the risk of cardiovascular death or heart failure (HF) hospitalization in patients with HF and preserved ejection fraction. This study aims to evaluate if systolic blood pressure (SBP) moderates these effects. METHODS AND RESULTS: The association of SBP and the treatment effects of empagliflozin in EMPEROR-Preserved (empagliflozin outcome trial in patients with chronic heart failure with preserved ejection fraction) was evaluated. Randomized patients (n 5988) were grouped according to SBP at baseline (110 mmHg, n 455; 110130 mmHg, n 2415; 130 mmHg, n 3118). The effect of empagliflozin on blood pressure, cardiovascular death or HF hospitalization (primary outcome), total HF hospitalizations, and rate of decline in estimated glomerular filtration rate was studied. Over a median of 26.2 months, the placebo-corrected decline was small and not significantly different across baseline SBP. On placebo, the risk of cardiovascular death or hospitalization for HF was 8.58 at 130 mmHg, 8.26 at 110130 mmHg, and 11.59 events per 100 patient-years at 110 mmHg (P 0.12 vs. 130 mmHg, P 0.08 vs. 110130 mmHg). There was no evidence for baseline SBP moderating the effect of empagliflozin on risk of HF events (primary endpoint interaction P 0.69, recurrent HF hospitalizations interaction P 0.55). When comparing empagliflozin with placebo, SBP did not meaningfully associate with adverse events such as hypotension, volume depletion, and acute renal failure. CONCLUSION: In EMPEROR-Preserved, empagliflozin was effective and safe without SBP meaningfully moderating empagliflozins treatment effects. This analysis of EMPEROR-Preserved shows that empagliflozin can be used safely and effectively without blood pressure being a meaningful moderator of the drug benefit. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov Unique identifier: NCT03057951
Targeting biofilms using phages and their enzymes
"Available online 10 March 2021"The complex biofilm architecture composed of extracellular polymeric structures (EPS) provides a protective shield to physiologically diverse bacterial cells immersed in its structure. The evolutionary interplay between bacteria and their viruses (phages) forced the latter ones to develop specific strategies to overcome the biofilm defensive barriers and kill sessile cells. Phages are equipped with a wide panel of enzyme-degrading EPS macromolecules which together are powerful weapons to combat biofilms. Antibiofilm performance can be achieved by combining phages or phage-borne enzymes with other antimicrobials such as antibiotics. Nevertheless, a variety of enzymes encoded in phage genomes still need to be explored. To advance in biofilm control strategies we must deepen the understanding of the biofilm biology itself, as well as discover and better exploit the unlimited antibacterial potential of phages.JA was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit. PG was supported by grants from Innovative Training
Networks (ITN) Marie Skłodowska-Curie Actions H2020-MSCA-ITN2018. Reference 813439, and PID2019-105311RB-I00 (MICIU/AEI/FEDER, UE, Spain). ZDK was supported by the National Science Centre
of Poland (Narodowe Centrum Nauki), grant numbers 2016/21/B/NZ6/01157 and 2017/26/M/NZ1/00233.info:eu-repo/semantics/publishedVersio
Avoiding Loss of Catalytic Activity of Pd Nanoparticles Partially Embedded in Nanoditches in SiC Nanowires
Nanoditches from selective etching of periodically twinned SiC nanowires were employed to hinder the migration and coalescence of Pd nanoparticles supported on the nanowires, and thus to improve their catalytic stability for total combustion of methane. The results show that the etched Pd/SiC catalyst can keep the methane conversion of almost 100% while the unetched one has an obvious decline in the catalytic activity from 100 to 82% after ten repeated reaction cycles. The excellent catalytic stability originates from the limitation of the nanoditches to the migration and growth of Pd nanoparticles
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