1,799 research outputs found
The molecular and crystal structure of (+)-mianserin hydrobromide
X-ray analysis of crystals of (+)-mianserin hydrobromide (1,2,3,4,10,14b-hexahydro-2-methyl-dibenzol[c,f]pyrazino[1,2-a]azepine) has established the stereochemistry and absolute configuration of this compound (S at 14b).\ud
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The crystals are orthorhombic with unit-cell dimensions: a = 1299(1)pm, b = 1420(1)pm, c = 1002(1)pm; Z = 4. The space group is P212121. Intensity data for about 1000 reflections were measured on a single-crystal diflractometer with Cu-Kα radiation. The crystal structure was solved by the heavy-atom method and refined by least-squares procedures. Final R-factor 9·4%. The absolute configuration was determined by Bijvoet's technique
Metabolic profiling reveals coordinated switches in primary carbohydrate metabolism in grape berry (Vitis vinifera L.), a non-climacteric fleshy fruit
Changes in carbohydrate metabolism during grape berry development play a central role in shaping the final composition of the fruit. The present work aimed to identify metabolic switches during grape development and to provide insights into the timing of developmental regulation of carbohydrate metabolism. Metabolites from central carbon metabolism were measured using high-pressure anion-exchange chromatography coupled to tandem mass spectrometry and enzymatic assays during the development of grape berries from either field-grown vines or fruiting cuttings grown in the greenhouse. Principal component analysis readily discriminated the various stages of berry development, with similar trajectories for field-grown and greenhouse samples. This showed that each stage of fruit development had a characteristic metabolic profile and provided compelling evidence that the fruit-bearing cuttings are a useful model system to investigate regulation of central carbon metabolism in grape berry. The metabolites measured showed tight coordination within their respective pathways, clustering into sugars and sugar-phosphate metabolism, glycolysis, and the tricarboxylic acid cycle. In addition, there was a pronounced shift in metabolism around veraison, characterized by rapidly increasing sugar levels and decreasing organic acids. In contrast, glycolytic intermediates and sugar phosphates declined before veraison but remained fairly stable post-veraison. In summary, these detailed and comprehensive metabolite analyses revealed the timing of important switches in primary carbohydrate metabolism, which could be related to transcriptional and developmental changes within the berry to achieve an integrated understanding of grape berry development. The results are discussed in a meta-analysis comparing metabolic changes in climacteric versus non-climacteric fleshy fruits
Gating of high-mobility two-dimensional electron gases in GaAs/AlGaAs heterostructures
We investigate high-mobility two-dimensional electron gases in AlGaAs
heterostructures by employing Schottky-gate-dependent measurements of the
samples' electron density and mobility. Surprisingly, we find that two
different sample configurations can be set in situ with mobilities diering by a
factor of more than two in a wide range of densities. This observation is
discussed in view of charge redistributions between the doping layers and is
relevant for the design of future gateable high-mobility electron gases
Multiple QTL-effects of wheat Gpc-B1 locus on grain protein and micronutrient concentrations
Micronutrient malnutrition afflicts over three billion peopleworldwide and the numbers are continuously increasing. Developing genetically micronutrientenriched cereals, which are the predominant source of human dietary, is essential to alleviate malnutrition worldwide. Wheat chromosome 6B derived from wild emmerwheat [Triticum turgidum ssp. dicoccoides (Körn.) Thell] was previously reported to be a source for high Zn concentration in the grain. In the present study, recombinant chromosome substitution lines (RSLs), previously constructed for genetic and physical maps of Gpc-B1 (a 250-kb locus affecting grain protein concentration), were used to identify the effects of the Gpc-B1 locus on grain micronutrient concentrations. RSLs carrying the Gpc-B1 allele of T. dicoccoides accumulated on average 12% higher concentration of Zn, 18% higher concentration of Fe, 29% higher concentration of Mn and 38% higher concentration of protein in the grain as compared with RSLs carrying the allele from cultivated wheat (Triticum durum). Furthermore, the high grain Zn, Fe and Mn concentrations were consistently expressed in five different environments with an absence of genotype by environment interaction. The results obtained in the present study also confirmed the previously reported effect of the wild-type allele of Gpc-B1 on earlier senescence of flag leaves. We suggest that the Gpc-B1 locus is involved in more efficient remobilization of protein, zinc, iron and manganese from leaves to the grains, in addition to its effect on earlier senescence of the green tissues
Preparation of atomically clean and flat Si(100) surfaces by low-energy ion sputtering and low-temperature annealing
Si(100) surfaces were prepared by wet-chemical etching followed by 0.3-1.5keV
Ar ion sputtering, either at elevated or room temperature. After a brief anneal
under ultrahigh vacuum conditions, the resulting surfaces were examined by
scanning tunneling microscopy. We find that wet-chemical etching alone cannot
produce a clean and flat Si(100) surface. However, subsequent 300eV Ar ion
sputtering at room temperature followed by a 973K anneal yields atomically
clean and flat Si(100) surfaces suitable for nanoscale device fabrication.Comment: 13 pages, 3 figures, to be published in Applied Surface Scienc
Carrier-Induced Magnetic Circular Dichloism in the Magnetoresistive Pyrochlore Tl2Mn2O7
Infrared magnetic circular dichloism (MCD), or equivalently magneto-optical
Kerr effect, has been measured on the Tl2Mn2O7 pyrochlore, which is well known
for exhibiting a large magnetoresistance around the Curie temperature T_C ~ 120
K. A circularly polarized, infrared synchrotron radiation is used as the light
source. A pronounced MCD signal is observed exactly at the plasma edge of the
reflectivity near and below T_c. However, contrary to the conventional behavior
of MCD for ferromagnets, the observed MCD of Tl2Mn2O7 grows with the applied
magnetic field, and not scaled with the internal magnetization. It is shown
that these results can be basically understood in terms of a classical
magnetoplasma resonance. The absence of a magnetization-scaled MCD indicates a
weak spin-orbit coupling of the carriers in Tl2Mn2O7. We discuss the present
results in terms of the microscopic electronic structures of Tl2Mn2O7.Comment: 5 pages, 5 figures, submitted to J. Phys. Soc. Jp
A Schedule of Duties in the Cloud Space Using a Modified Salp Swarm Algorithm
Cloud computing is a concept introduced in the information technology era,
with the main components being the grid, distributed, and valuable computing.
The cloud is being developed continuously and, naturally, comes up with many
challenges, one of which is scheduling. A schedule or timeline is a mechanism
used to optimize the time for performing a duty or set of duties. A scheduling
process is accountable for choosing the best resources for performing a duty.
The main goal of a scheduling algorithm is to improve the efficiency and
quality of the service while at the same time ensuring the acceptability and
effectiveness of the targets. The task scheduling problem is one of the most
important NP-hard issues in the cloud domain and, so far, many techniques have
been proposed as solutions, including using genetic algorithms (GAs), particle
swarm optimization, (PSO), and ant colony optimization (ACO). To address this
problem, in this paper, one of the collective intelligence algorithms, called
the Salp Swarm Algorithm (SSA), has been expanded, improved, and applied. The
performance of the proposed algorithm has been compared with that of GAs, PSO,
continuous ACO, and the basic SSA. The results show that our algorithm has
generally higher performance than the other algorithms. For example, compared
to the basic SSA, the proposed method has an average reduction of approximately
21% in makespan.Comment: 15 pages, 6 figures, 2023 IFIP International Internet of Things
Conference. Dallas-Fort Worth Metroplex, Texas, US
Genealogical typing of Neisseria meningitidis
Despite the increasing popularity of multilocus sequence typing (MLST), the most appropriate method for characterizing bacterial variation and facilitating epidemiological investigations remains a matter of debate. Here, we propose that different typing schemes should be compared on the basis of their power to infer clonal relationships and investigate the utility of sequence data for genealogical reconstruction by exploiting new statistical tools and data from 20 housekeeping loci for 93 isolates of the bacterial pathogen Neisseria meningitidis. Our analysis demonstrated that all but one of the hyperinvasive isolates established by multilocus enzyme electrophoresis and MLST were grouped into one of six genealogical lineages, each of which contained substantial variation. Due to the confounding effect of recombination, evolutionary relationships among these lineages remained unclear, even using 20 loci. Analyses of the seven loci in the standard MLST scheme using the same methods reproduced this classification, but were unable to support finer inferences concerning the relationships between the members within each complex
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