581 research outputs found
Poly[diaqua-μ2-oxalato-di-μ4-succinato-diyttrium(III)]
In the title compound, [Y2(C4H4O4)2(C2O4)(H2O)2]n, the flexible succinate anion assumes a gauche conformation and bridges the eight-coordinated Y atoms, generating two-dimensional layers parallel to (010). The coordination polymer layers are linked into a three-dimensional framework by the rigid oxalate ligands. The oxalate ions are located on a center of inversion. Intermolecular O—H⋯O hydrogen bonds help to stabilize the crystal structure
Energy Efficient Multiresource Allocation of Virtual Machine Based on PSO in Cloud Data Center
Presently, massive energy consumption in cloud data center tends to be an escalating threat to the environment. To reduce energy consumption in cloud data center, an energy efficient virtual machine allocation algorithm is proposed in this paper based on a proposed energy efficient multiresource allocation model and the particle swarm optimization (PSO) method. In this algorithm, the fitness function of PSO is defined as the total Euclidean distance to determine the optimal point between resource utilization and energy consumption. This algorithm can avoid falling into local optima which is common in traditional heuristic algorithms. Compared to traditional heuristic algorithms MBFD and MBFH, our algorithm shows significantly energy savings in cloud data center and also makes the utilization of system resources reasonable at the same time
A convenient tandem one-pot synthesis of donor-acceptor-type triphenylene 2,3-dicarboxylic esters from diarylacetylene
A tandem one-pot method for the direct synthesis of polysubstituted triphenylene 2,3-dicarboxylic esters with different substitution patterns was developed by enyne metathesis of diarylacetylene, followed by Diels–Alder, aromatization and a cyclization cascade
Bis(N-phenylethane-1,2-diamine)dithiocyanatonickel(II)
The asymmetric unit of the title mononuclear NiII compound, [Ni(NCS)2(C8H12N2)2], contains two independent half-molecules, the Ni atoms of which lie on crystallographic inversion centres. Each NiII ion is chelated by two N atoms from two N-phenylethane-1,2-diamine ligands and is also coordinated by two N atoms from two thiocyanate ligands, giving a distorted octahedral geometry. In the crystal, molecules are linked into a two-dimensional network parallel to (100) by N—H⋯S interactions
3-(2-Bromoethoxy)-4-(4-bromophenyl)furan-5(2H)-one
In the title compound, C12H10Br2O3, the dihedral angle between the furan-5(2H)-one ring and the benzene ring is 1.2 (3)°. Two intramolecular C—H⋯O interactions occur in the molecule, both of which generate S(6) rings. The bromoethyl fragment is disordered over two sets of sites in a 0.773 (8):0.227 (8) ratio. In the crystal, inversion dimers linked by pairs of C—H⋯π interactions occur
Phylogeography of the Sino-Himalayan Fern Lepisorus clathratus on “The Roof of the World”
The Qinghai-Tibetan Plateau (QTP) and its southern and southeastern mountain ranges, Himalaya-Hengduan Mountains (HHM), are one of the most extensive habitats for alpine plants in the world. How ferns occurring in QTP and HHM changed their distribution ranges in response to Quaternary climatic oscillations remains almost unknown.We employed sequences of two chloroplast DNA regions, rps4-trnS and trnL-trnF, to reconstruct phylogeography of the Sino-Himalayan fern Lepisorus clathratus, occurring mainly in the QTP and HHM. Individuals of this species have either dehiscent or indehiscent sporangia with the latter evolved from the plesiomorphic dehiscent forms. Based on a range-wide sampling, we detected 27 cpDNA haplotypes that were divided into five groups by network analyses. Populations in the Hengduan Mountains possess the highest genetic diversity, while a single haplogroup is detected across the north-central region. A distinct phylogeographical subdivision was detected between the Hengduan Mountains and north-central region by AMOVA analysis. The haplogroup distribution pattern, coalescence and AMOVA analysis suggest that a long term survival area (refugia) of the species was located in the Hengduan Mountains during glaciations, with probable range expansions into north-central regions during interglacial periods. Populations with indehiscent sporangium can carry private haplotypes and are inclined to maintain genetic homogeneity. One group with indehiscent sporangia most likely survived in situ on the QTP during glaciations.This study for the first time sheds light on the response of alpine ferns in the QTP and HHM to the Quaternary climatic oscillations
Management of male erectile dysfunction: From the past to the future
Erectile dysfunction is a common disease of the male reproductive system, which seriously affects the life quality of patients and their partners. At present, erectile dysfunction is considered as a social-psychological-physiological disease with complex etiology and various treatment methods. Oral PDE5I is the first-line treatment for erectile dysfunction with the advantages of high safety, good effect and non-invasiveness. But intracavernosal injection, hormonal replacement therapy, vacuum erection device, penile prosthesis implantation can also be alternative treatments for patients have organic erectile dysfunction or tolerance to PDE5I. With the rapid development of technologies, some new methods, such as low-intensity extracorporeal shock wave and stem cell injection therapy can even repair the organic damage of the corpora cavernosa. These are important directions for the treatment of male erectile dysfunction in the future. In this mini-review, we will introduce these therapies in detail
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