ABSTRACT
Recent studies have revealed that the interlayer interaction in two-dimensional (2D) layered materials is not simply of van der Waals character but could coexist with quasi-bonding character. Herein, we classify the interlayer quasi-bonding interactions into two main categories (I: homo-occupancy interaction; II: hetero-occupancy interaction) according to the occupancy of the involved energy bands near the Fermi level. We then investigate the quasi-bonding-interaction-induced band structure evolution of several representative 2D materials based on density functional theory calculations. Further calculations confirm that this classification is applicable to generic 2D layered materials and provide a unified understanding of the total strength of interlayer interaction, which is a synergetic effect of the van der Waals attraction and the quasi-bonding interaction. The latter is stabilizing in main category II and destabilizing in main category I. Thus, the total interlayer interaction strength is relatively stronger in category II and weaker in category I.
ABSTRACT
BACKGROUND: The association studies of killer cell immunoglobulin-like receptors (KIRs) with the occurrence of myelodysplastic syndromes (MDS) are limited worldwide; this study investigated the genetic risk/protective factors of MDS in KIR and human leucocyte antigen (HLA) systems to gain a better understanding of the role played by KIR and their cognate HLA ligands in MDS pathogenesis. METHODS: We genotyped a total number of 77 patients with MDS from Chinese Southern Han and 745 healthy controls for the KIR loci and HLA class I. The carrier frequencies of KIR genes, KIR genotypes, class I HLA ligands, and KIR-HLA combinations were calculated by direct counting. The effect of individual KIR genes and HLA ligands on MDS risk was evaluated by logistic regression analyses using SAS 9.2 software. RESULTS: We found that neither the KIR genes nor the KIR genotypes were associated with the occurrence of MDS. However, we observed that the frequencies for the strong inhibitory ligand HLA-Bw4 as well as KIR3DL1-HLA-Bw4 combination were significantly higher in healthy controls than those in the MDS patient group, respectively (73.42% vs. 62.34%, P = 0.038; 70.87% vs. 59.74%, P = 0.043). CONCLUSION: Our results showed that HLA-Bw4 ligand and KIR3DL1-HLA-Bw4 combination could confer a protective effect against MDS in Chinese Southern Han.
Subject(s)
Genotype , HLA-B Antigens/genetics , Myelodysplastic Syndromes/genetics , Receptors, KIR3DL1/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Asian People/ethnology , China/ethnology , Female , Humans , Male , Middle Aged , Myelodysplastic Syndromes/ethnologyABSTRACT
The traditional Back Propagation (BP) has some significant disadvantages, such as training too slowly, easiness to fall into local minima, and sensitivity of the initial weights and bias. In order to overcome these shortcomings, an improved BP network that is optimized by Cuckoo Search (CS), called CSBP, is proposed in this paper. In CSBP, CS is used to simultaneously optimize the initial weights and bias of BP network. Wine data is adopted to study the prediction performance of CSBP, and the proposed method is compared with the basic BP and the General Regression Neural Network (GRNN). Moreover, the parameter study of CSBP is conducted in order to make the CSBP implement in the best way.
Subject(s)
Algorithms , Models, Theoretical , Neural Networks, ComputerABSTRACT
In the crystal of the title compound, C(18)H(22)N(2)O(4)S·2H(2)O, mol-ecules are linked into a one-dimensional chain structure by C-Hâ¯O, N-Hâ¯O, O-Hâ¯O and O-Hâ¯N hydrogen bonds.
ABSTRACT
In the title mol-ecular salt, [Co(H(2)O)(6)](C(7)H(8)NO(3)S)(2), the Co(2+) cation lies on an inversion centre. In the crystal, the components are linked by N-Hâ¯O and O-Hâ¯O hydrogen bonds, thereby generating sheets parallel to (001).
ABSTRACT
In the title mol-ecular salt, [Mg(H(2)O)(6)](C(7)H(8)NO(3)S)(2), the Mg(2+) cation lies on an inversion centre. In the crystal, the components are linked by N-Hâ¯O and O-Hâ¯O hydrogen bonds, thereby generating sheets parallel to (001).
ABSTRACT
In the title compound, [Ni(CH(5)N(3)S)(2)](C(8)H(8)N(3)O(3)S(2))(2)·2H(2)O, the Ni(II) atom lies on a inversion centre and is four-coordinated by two N and two S atoms of two thio-semicarbazide ligands in an almost square-planar coordination. In the crystal structure, the molecules are linked into a three-dimensional network via C-Hâ¯O, C-Hâ¯N, N-Hâ¯O, N-Hâ¯S and O-Hâ¯O hydrogen bonds.
