catena-Poly[[bis­[3-(1H-imidazol-1-yl)-1-phenyl­propan-1-one-κN 3]nickel(II)]-μ-oxalato-κ4 O 1,O 2:O 1′,O 2′]

In the title compound, [Ni(C2O4)(C12H12N2O)2]n, the NiII atom, lying on a twofold rotation axis, is coordinated by two N atoms from two monodentate 3-(1H-imidazol-1-yl)-1-phenyl­propan-1-one (L) ligands and four O atoms from two oxalate anions in a distorted octa­hedral geometry. The oxalate anion has a twofold rotation axis through the mid-point of the C—C bond and acts as a bridging ligand, linking the NiII atoms into a polymeric chain along [010]. Weak inter­molecular C—H⋯O hydrogen bonds connect the chains, resulting in a three-dimensional supra­molecular structure.

Di-μ-chlorido-bis­{[2-(2-pyridylmethyl­amino)ethanesulfonato-κ3 N,N′,O]copper(II)}

In the title compound, [Cu2(C8H11N2O3S)2Cl2], the Cu atoms are five-coordinated in a distorted square-pyramidal geometry by three donor atoms of the deprotonated anionic 2-(2-pyridylmethyl­amino)ethanesulfonate (pmt) ligand and two Cl atoms. The Cl atoms bridge two Cu atoms, giving a binuclear structure; the centroid of the Cu2Cl2 ring lies on a crystallographic center of inversion. The complex is stabilized by hydrogen bonds and π–π stacking inter­actions [average inter­planar distance = 3.4969 (1) Å and ring-centroid separation distance = 4.1068 (4) Å]

Supporting Undergraduate Research: Recommending Personalized Research Projects to Undergraduates

Undergraduates’ participation in faculty-mentored research is becoming an important issue in tertiary education in recent years, and it benefits both undergraduates and faculty members. In reality, many faculty members have research projects that need help from undergraduates, but undergraduates can hardly find the information, which creates information asymmetry problem. Besides, undergraduates lack the experience of doing academic research, the research interest information is incomplete, so they have difficulties in choosing suitable research projects. Thus recommender systems are necessary to facilitate undergraduates’ participation in research projects. Traditional recommendation approaches require relative complete information for decision making, and they can hardly meet the requirements as undergraduates’ research information is incomplete. In this study, we propose a two-stage model that integrates content-based method with collaborative method by leveraging research social networks, where undergraduates are encouraged to connect with faculty members and participate in social network activities, through which research information is collected. The proposed two-stage model alleviates the problems of information asymmetry and incomplete information. The recommender system has been developed in ScholarMate (www.scholarmate.com), and it allows undergraduates to choose suggested research projects

2-Phenyl­imidazolium hemi(benzene-1,3-dicarboxyl­ate) monohydrate

The asymmetric unit of the title compound, C9H9N2 +·0.5C8H4O4 −·H2O, contains one 2-phenyl­imidazolium cation, half a benzene-1,3-dicarboxyl­ate anion and one water mol­ecule. In the crystal, components are connected by N—H⋯O and O—H⋯O hydrogen-bonding inter­actions into a three-dimensional network

2,5-Bis(5-methyl­pyrazin-2-yl)-1,3,4-oxadiazole

In the title mol­ecule, C12H10N6O, the dihedral angle between the two pyrazine rings [planar to within 0.009 (3) and 0.018 (3) Å] is 5.62 (15)°. They deviate from the central oxadiazole ring [planar to within 0.005 (3) Å] by 1.52 (16) and 5.55 (17)°, respectively. In the crystal, C—H⋯N inter­actions involving the pyrazine rings connect mol­ecules to form zigzag supramolecular chains propagating in [010]

Relations between near-field enhancements and Purcell factors in hybrid nanostructures of plasmonic antennas and dielectric cavities

Strong near-field enhancements (NFEs) of nanophotonic structures are believed to be closely related to high Purcell factors (FP). Here, we theoretically show that the correlation is partially correct; the extinction cross section ({\sigma}) response is also critical in determining FP. The divergence between NFE and FP is especially pronounced in plasmonic-dielectric hybrid systems, where the plasmonic antenna supports dipolar plasmon modes and the dielectric cavity hosts Mie-like resonances. The cavity's enhanced-field environment can boost the antenna's NFEs, but the FP is not increased concurrently due to the larger effective {\sigma} that is intrinsic to the FP calculations. Interestingly, the peak FP for the coupled system can be predicted by using the NFE and {\sigma} responses. Furthermore, the limits for FP of coupled systems are considered; they are determined by the sum of the FP of a redshifted (or modified, if applicable) antenna and an individual cavity. This contrasts starkly with the behavior of NFE which is closely associated with the multiplicative effects of the NFEs provided by the antenna and the dielectric cavity. The differing behaviors of NFE and FP in hybrid cavities have varied impacts on relevant nanophotonic applications such as fluorescence, Raman scattering and enhanced light-matter interactions

A wear-resistant metastable CoCrNiCu high-entropy alloy with modulated surface and subsurface structures

Sliding friction-induced subsurface structures and severe surface oxidation can be the major causes influencing the wear resistance of ductile metallic materials. Here, we demonstrated the role of subsurface and surface structures in enhancing the wear resistance of an equiatomic metastable CoCrNiCu high-entropy alloy (HEA). The CoCrNiCu HEA is composed of a CoCrNi-rich face-centered cubic (FCC) dendrite phase and a Cu-rich FCC inter-dendrite phase. Copious Cu-rich nano-precipitates are formed and distributed uniformly inside the dendrites after tuning the distribution and composition of the two phases by thermal annealing. Although the formation of nano-precipitates decreases the hardness of the alloy due to the loss of solid solution strengthening, these nano-precipitates can be deformed to form continuous Cu-rich nanolayers during dry sliding, leading to a self-organized nano-laminated microstructure and extensive hardening in the subsurface. In addition, the nano-precipitates can facilitate the formation of continuous and compacted glaze layers on the worn surface, which are also beneficial for the reduction of the wear rate of CoCrNiCu. The current work can be extended to other alloy systems and might provide guidelines for designing and fabricating wear-resistant alloys in general

Effect of Tumor Necrosis Factor-α on Neutralization of Ventricular Fibrillation in Rats with Acute Myocardial Infarction

The purpose of this study was to explore the effects of tumor necrosis factor-α (TNF-α) on ventricular fibrillation (VF) in rats with acute myocardial infarction (AMI). Rats were randomly classified into AMI group, sham operation group and recombinant human tumor necrosis factor receptor:Fc fusion protein (rhTNFR:Fc) group. Spontaneous and induced VFs were recorded. Monophasic action potentials (MAPs) among different zones of myocardium were recorded at eight time points before and after ligation and MAP duration dispersions (MAPDds) were calculated. Then expression of TNF-α among different myocardial zones was detected. After ligation of the left anterior descending coronary artery, total TNF-α expression in AMI group began to markedly increase at 10 min, reached a climax at 20–30min, and then gradually decreased. The time-windows of VFs and MAPDds in the border zone performed in a similar way. At the same time-point, the expression of TNF-α in the ischemia zone was greater than that in the border zone, and little in the non-ischemia zone. Although the time windows of TNF-α expression, the MAPDds in the border zone and the occurrence of VFs in the rhTNFR:Fc group were similar to those in the AMI group, they all decreased in the rhTNFR:Fc group. Our findings demonstrate that TNF-α could enlarge the MAPDds in the border zone, and promote the onset of VFs