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Motifs of planar metalloborophenes, cage-like metalloborospherenes, and metal-centered double-ring tubular boron species have been reported. Based on extensive first-principles theory calculations, we present herein the possibility of doping the quasi-planar C2v B56 (A-1) with an alkaline-earth metal to produce the penta-ring tubular Ca©B56 (B-1) which is the most stable isomer of the system obtained and can be viewed as the embryo of metal-doped (4,0) boron α-nanotube Ca©BNT(4,0) (C-1). Ca©BNT(4,0) (C-1) can be constructed by rolling up the most stable boron α-sheet and is predicted to be metallic in nature. Detailed bonding analyses show that the highly stable planar C2v B56 (A-1) is the boron analog of circumbiphenyl (C38H16) in π-bonding, while the 3D aromatic C4v Ca©B56 (B-1) possesses a perfect delocalized π system over the σ-skeleton on the tube surface. The IR and Raman spectra of C4v Ca©B56 (B-1) and photoelectron spectrum of its monoanion C4v Ca©B56− are computationally simulated to facilitate their spectroscopic characterizations. [ABSTRACT FROM AUTHOR]

Because of its novel physical properties, two-dimensional materials have attracted great attention. From first-principle calculations and vibration frequencies analysis, we predict a new family of two-dimensional materials based on the idea of octet stability: honeycomb lattices of pnictogens (N, P, As, Sb, Bi). The buckled structures of materials come from the sp3 hybridization. These materials have indirect band gap ranging from 0.43 eV to 3.7 eV. From the analysis of projected density of states, we argue that the s and p orbitals together are sufficient to describe the electronic structure under tight-binding model, and the tight-binding parameters are obtained by fitting the band structures to first-principle results. Surprisingly large on-site spin-orbit coupling is found for all the pnictogen lattices except nitrogen. Investigation on the electronic structures of both zigzag and armchair nanoribbons reveals the possible existence of spin-polarized ferromagnetic edge states in some cases, which are rare in one-dimensional systems. These edge states and magnetism may exist under the condition of high vacuum and low temperature. This new family of materials would have promising applications in electronics, optics, sensors, and solar cells. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the gender-related differences of disease onset, age distribution, blood type, clinical characteristics, and malignant behaviors of differentiated thyroid carcinoma (DTC) in Chinese patients. A total of 7385 consecutive thyroid cancer patients who underwent thyroidectomy were retrospectively reviewed. 4087 (55.3%) were diagnosed as benign and the other (3298, 44.7%) were as malignant. DTC accounted for 97.6% in the malignant tumor. More single nodules turned out to be DTC in male compared to multiple nodules (46.9% vs. 40.4%, P = 0.004). The proportion increased along with the increase of year during 2000-2013, which was from 7.5% to 68.1% in males and from 16.2% to 66.7% in females. The level of preoperative TSH was significantly higher in patients with DTC compared to the patients with benign (1.97 vs. 1.57 mIU/L, P < 0.001). The proportion of thyroid cancer was dominated in blood type B and the lowest incidence in blood type A in male, the difference was not statistically significant. The results showed that age, nodule number, BMI and serum TSH were the related factors for DTC. More aggressive behaviors of DTC were observed in male patients, and more attention should be focused on the timely diagnosis and treatment of these patients.

Paddy soils have been widely recognized as important carbon sinks. However, paddy field abandonment is increasing in the hilly area in subtropical China. Soil waterlogging and weed burning are common practices in abandoned paddy fields, which could affect vegetation cover and carbon sequestration. An rice cultivation experiment was ceased in 2006, and four new treatments were applied as waterlogging (W), drainage (D), waterlogging combined with burning (WB), and drainage combined with burning (DB). Waterlogging altered the vegetation cover and caused an associated change in biomass. Paspalum paspaloides, Murdannia triquetra, and Bidens frondosa dominated W and WB plots, and Microstegium vimineum and Bidens frondosa dominated D and DB plots. Abandonment of paddy fields led to a rapid decrease in soil organic carbon (SOC), and waterlogging accelerates SOC loss which should be attributed mainly to alteration of the vegetation cover. Six years' rice cultivation increased SOC content by 13.5% (2.4 g kg -1 ) on average. In contrast, six years' abandonment reduced SOC content by 14.5% (3.0 g kg -1 ) on average. Decline rate of SOC was 0.38, 0.64, 0.30, and 0.65 g kg -1 a -1 for D, W, DB, and WB, respectively. Such results indicate a significant risk of SOC loss from abandoned paddy fields.

Motifs of planar metalloborophenes, cage-like metalloborospherenes, and metal-centered double-ring tubular boron species have been reported. Based on extensive first-principles theory calculations, we present herein the possibility of doping the quasi-planar C 2v B 56 (A-1) with an alkaline-earth metal to produce the penta-ring tubular Ca©B 56 (B-1) which is the most stable isomer of the system obtained and can be viewed as the embryo of metal-doped (4,0) boron α-nanotube Ca©BNT (4,0) (C-1). Ca©BNT (4,0) (C-1) can be constructed by rolling up the most stable boron α-sheet and is predicted to be metallic in nature. Detailed bonding analyses show that the highly stable planar C 2v B 56 (A-1) is the boron analog of circumbiphenyl (C 38 H 16 ) in π-bonding, while the 3D aromatic C 4v Ca©B 56 (B-1) possesses a perfect delocalized π system over the σ-skeleton on the tube surface. The IR and Raman spectra of C 4v Ca©B 56 (B-1) and photoelectron spectrum of its monoanion C 4v Ca, (©B are computationally simulated to facilitate their spectroscopic characterizations.)