Heterobimetallic Cluster-Based Coordination Polymers: Assembly,Structures and Third-Order Nonlinear Optical Properties

Reactions of (NH₄)₂WS₄ with CuCN, CuCN/1,2-bis(4-pyridyl)propane (bppa) or [Cu(MeCN)₄]PF₆/bppa under different reaction conditions afforded a set of two- or three-dimensional W/Cu/S cluster-based coordination polymers including {[Et₄N]₂[WS₄Cu₄(μ-CN)₂(μ-I)₂]}_n ( 1 ), [WS₄Cu₄(μ-CN)₂(bppa)₂]_n ( 2 ) and {[WS₄Cu₄(bppa)₄](PF₆)₂}_n ( 3 ), respectively. Compound 2 can be readily formed from reaction of 1 with bppa under solvothermal conditions. Compounds 1 and 2 feature two-dimensional networks with a “sql” topology, while 3 possesses a two-fold interpenetrated three-dimensional net with a rare “reo” topology. Compounds 1 – 3 in DMF exhibited different third-order nonlinear optical responses, and they all showed a reverse saturable absorption while 2 held a strong self-focusing effect.     

Potential Role of Melatonin as an Adjuvant for Atherosclerotic Carotid Arterial Stenosis

Carotid artery stenosis (CAS) is an atherosclerotic disease characterized by a narrowing of the artery lumen and a high risk of ischemic stroke. Risk factors of atherosclerosis, including smoking, hypertension, hyperglycemia, hyperlipidemia, aging, and disrupted circadian rhythm, may potentiate atherosclerosis in the carotid artery and further reduce the arterial lumen. Ischemic stroke due to severe CAS and cerebral ischemic/reperfusion (I/R) injury after the revascularization of CAS also adversely affect clinical outcomes. Melatonin is a pluripotent agent with potent anti-inflammatory, anti-oxidative, and neuroprotective properties. Although there is a shortage of direct clinical evidence demonstrating the benefits of melatonin in CAS patients, previous studies have shown that melatonin may be beneficial for patients with CAS in terms of reducing endothelial damage, stabilizing arterial plaque, mitigating the harm from CAS-related ischemic stroke and cerebral I/R injury, and alleviating the adverse effects of the related risk factors. Additional pre-clinical and clinical are required to confirm this speculation.     

Apportionment of wind from water erosion on the hillslopes of China Northern Loess Hilly Area,by the fallout 137Cs technique

Journal of Radioanalytical and Nuclear Chemistry - Differences in the net soil loss and apportionment of wind from water erosion on hillslopes were analyzed and evaluated quantitatively through...     

Dynamic analysis and regulation of the flexible pipe conveying fluid with a hard-magnetic soft segment

Applied Mathematics and Mechanics - The recently developed hard-magnetic soft (HMS) materials can play a significant role in the actuation and control of medical devices, soft robots, flexible...     

Vitamin K1 distribution following intravenous vitamin K1–fat emulsion administration in rats

This study investigated vitamin K₁ (VK₁) distribution following intravenous vitamin K₁–fat emulsion (VK₁–FE) administration and compared it with that after VK₁ injection. Rats were intravenously injected with VK₁–FE or VK₁. The organ and tissue VK₁ concentrations were determined using high‐performance liquid chromatography method at 0.5, 2 and 4 h to determine distribution, equilibrium and elimination phases, respectively. In the VK₁–FE group, the plasma, heart and spleen VK₁ concentrations decreased over time. However, other organs like liver, lung, kidney, muscle and testis, reached peak VK₁ concentrations at 2 h. In the VK₁ injection group, the liver VK₁ concentrations were significantly higher than those in other organs at the three time points. However, VK₁ concentrations in the other organs peaked at 2 h. In addition, in VK₁–FE group, the heart, spleen and lung VK₁ concentrations were significantly higher than those in the VK₁ injection group at the three time points, and the liver VK₁ concentration was significantly higher than that in the VK₁ injection group at 4 h. The VK₁ amount was greatest in the liver compared with the other organs. Thus, the liver is the primary organ for VK₁ distribution. The distribution of VK₁ is more rapid when injected as VK₁–FE than as VK₁. Copyright © 2015 John Wiley & Sons, Ltd.     

Screening of drugs of abuse and toxic compounds in human whole blood using online solid‐phase extraction and high‐performance liquid chromatography with time‐of‐flight mass spectrometry

A novel method for the screening of 151 drugs of abuse and toxic compounds in human whole blood has been developed and validated by online solid‐phase extraction with liquid chromatography coupled to time‐of‐flight mass spectrometry. Analytes were extracted and separated by using a fully automated online solid‐phase extraction liquid chromatography system with total chromatographic run time of 26 min. Time‐of‐flight mass spectrometry screening of 151 drugs of abuse and toxic compounds was performed in a full‐scan (m/z 50–800) mode using an MS^E acquisition of molecular ions and fragment ions data at two collision energies (one was 6 eV and another one was in the range of 5–45 eV). The compounds were identified based on retention times and exact mass of molecular ions and fragment ions. The limit of detection ranged from 1 to 100 ng/mL and the recovery of the method ranged from 6.3 to 163.5%. This method is proved to be a valuable screening method allowing fast and specific identification of drugs in human whole blood.     

Automated headspace solid‐phase microextraction and on‐fiber derivatization for the determination of clenbuterol in meat products by gas chromatography coupled to mass spectrometry

A method was developed for the determination of clenbuterol in meat using stable‐isotope‐dilution gas chromatography with mass spectrometry coupled with solid‐phase microextraction and on‐fiber derivatization. The samples were first homogenized with hydrochloric acid followed by protein deposition. After headspace solid‐phase microextraction and on‐fiber derivatization, the content of clenbuterol was measured with the aid of stable‐isotope dilution. The condition of solid‐phase microextraction was optimized by central composite design. The relative standard deviations, limit of detection, and recoveries for clenbuterol were 4.2–9.2%, 0.48 μg/kg, and 96–104%, respectively. The proposed method was satisfactory for analysis of real samples as compared with the Chinese standard method.     

High-performance supercapacitor electrode based on a nanocomposite of polyaniline and chemically exfoliated MoS<Subscript>2</Subscript> nanosheets

In this study, MoS₂ nanosheets were first prepared by exfoliating its bulk material in HCl/LiNO₃ solution with a yield of 45%, and then a facile strategy was developed to synthesize polyaniline/MoS₂ (PANI/MoS₂) nanocomposite via in situ polymerization. Structural and morphological characterizations of MoS₂ nanosheets and the nanocomposite were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray powder diffraction. The results of SEM illustrated that orderly sawtooth polyaniline (PANI) nanoarrays were formed on the surface of MoS₂ nanosheets. The nanocomposite displayed good electrochemical performance as a supercapacitor electrode material. The specific capacitance reached 560 F/g at a current density of 1.0 A g^?1 in 1.0 M H₂SO₄ solution. Such good performance is because that the MoS₂ nanosheets provided a highly electrolytic accessible surface area for redox-active PANI and a direct path for electrons.