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The synthesis of alkynyl trifluoromethyl selenoethers from copper‐mediated aerobic decarboxylative trifluoromethylselenolation of alkynyl carboxylic acids with [Me4N][SeCF3] is reported. The reaction proceeded smoothly under mild conditions and enabled the facile conversion of both aryl and alkyl alkynyl carboxylic acids to the corresponding trifluoromethyl selenoethers in good yields, demonstrating that decarboxylative trifluoromethylselenolation of alkynyl carboxylic acids with the nucleophilic [Me4N][SeCF3] reagent is feasible at ambient temperature without irradiation. Advantages of the method include the use of bench‐stable and non‐volatile alkynyl carboxylic acids as starting materials, readily accessible SeCF3 reagent, excellent functional group tolerance, and the avoidance of harsh reaction conditions. This copper‐mediated reaction represents the first decarboxylative trifluoromethylselenolation of alkynyl carboxylic acids with a SeCF3 source. [ABSTRACT FROM AUTHOR]

Rationale: Diaryliodonium salts are useful electrophilic reagents in organic chemistry, finding extensive applications in arylations and photo-induced polymerizations. However, comprehensive mechanistic investigations, particularly concerning the mass spectrometric behaviors of diaryliodonium salts, are relatively scarce in the literature. Methods: Diaryliodonium salts could be readily ionized using electrospray ionization mass spectrometry (ESI-MS) to give [Ar¹ -I+-Ar² ], and high-resolution ESI-tandem mass spectrometry (MS/MS) experiments were conducted to investigate their gasphase chemical reactions. Results: Investigations on ESI-MS/MS of [Ar¹-I+-Ar² ] revealed two major fragmentation patterns: (1) reductive elimination resulting in the diaryl coupling product ion [Ar¹ -Ar² ] +• by the loss of I; (2) generation of aryl cations [Ar¹ ] + or [Ar² ] + through cleavage of the C–I bonds. We revealed that the introduction of NO2 into Ar² of [Ar¹ -I+-Ar² ] could lead to an unexpected fragmentation ion [Ar¹ O]+ in MS/MS, arising from an O-atom transfer process from NO² to Ar¹ . Particularly, when NO2 was ortho-positioned to the iodine in Ar², the [Ar¹ O]+ sometimes exhibited dominant behavior. Conclusions: Comprehensive ESI-MS/MS studies and theoretical calculations provided strong support for the O-atom transfer mechanistic pathway: [Ar¹ -I+- (o-NO2-Ar² )] initially underwent a Smiles rearrangement to the intermediate [Ar¹ -O- (o-NO-Ar² I)]+, which subsequently dissociated to [Ar¹ O]+ or [o-NO-Ar² I]+• . Herein, we proposed an unexpected “ortho effect” in the gas-phase fragmentation reaction of [Ar¹ -I+-(o-NO2-Ar² )], in which the crucial determinant factor for the aryl migration was identified as the Smiles rearrangement reaction. [ABSTRACT FROM AUTHOR]

Carbamoyl fluorides, fluoroformates, and their analogues are a class of important compounds and have been evidenced as versatile building blocks for the preparation of useful molecules in organic chemistry. While major achievements were made in the synthesis of carbamoyl fluorides, fluoroformates, and their analogues in the last half of 20th century, an increasing number of reports have focused on using O/S/Se=CF2 species or their equivalents as the fluorocarbonylation reagents for the direct construction of these compounds from the parent heteroatom‐nucleophiles in recent years. This review mainly summarizes the advances in the synthesis and typical application of carbamoyl fluorides, fluoroformates, and their analogues by the halide exchanges and fluorocarbonylation reactions since 1980. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling (PDRC) is a promising strategy to realize surface cooling of objects without any external energy consumption. While such materials typically exhibit dazzling white appearances, developing pleasingly looking colored radiative cooling materials is greatly significant but remains an arduous challenge. Herein, self-standing, flexible colored films available on both sides are prepared by using a facile and scalable strategy. The films are asymmetrically designed. One side is SiO2-filled porous structure with highly reflective pigment distributed that can selectively reflect solar light to generate specific color, and the other side is hierarchically porous three-phase composite with less SiO2, which maximizes the solar reflection. The breathable film achieves a relatively high near infrared reflectance on the colored side (up to 89%), and a broadband solar reflectance on the reverse side. Moreover, both sides exhibit extremely high mid-infrared emissivity (98%) allowing significant radiative heat loss. With the diverse but efficient reflectance and emittance, different sides of three colored films yield temperature drops ranging from 2.0 to 11.1 °C during daytime. Building energy simulation indicates that 655 MJm-2 energy can be saved over the whole summer if the dual-sided available colored film is deployed in China. [ABSTRACT FROM AUTHOR]

Metal‐free trifluoromethyltellurolation of indoles with [Me4N][TeCF3] in the presence of NIS allowed a convenient synthesis of 3‐TeCF3‐substituted indole derivatives in good yields. The reaction proceeded smoothly under mild conditions and showed good functional group tolerance. It was noteworthy that [Me4N][TeCF3] had a distinct reaction profile for indole systems in comparison with [Me4N][SeCF3]. The trifluoromethyltellurolated products were unprecedented and decomposed rapidly even in the darkness and under a N2 atmosphere. This work represents the first metal‐free trifluoromethyltellurolation of indoles with the sensitive [Me4N][TeCF3] salt as TeCF3 reagent. [ABSTRACT FROM AUTHOR]

In this work, high efficiency and multifunctional poly(vinyl alcohol‐co‐ethylene) nanofiber, Ag particle, and polypropylene (PP) meltblown nonwoven substrate composite (NF@Ag) air filters by a simple spray coating method and subsequent UV irradiation treatment are demonstrated. The water vapor transmission rate of the NF@Ag‐4 air filter is 4753.36 ± 316.75 g/(m2 d), which is higher than that of commercial PP nonwoven (4240.71 ± 354.36 g/(m2 d)). It is can be explained that the NF@Ag‐4 air filter is a Janus structure with asymmetric wettability, which enhances moisture permeability, thereby improving comfort while wearing. The NF@Ag‐2 air filter exhibits high filtration efficiency (95.80 ± 0.89%) and relatively low pressure drop (122.00 ± 1.73 Pa) without relying on the electrostatic adsorption effect. The resulting NF@Ag air filters display excellent antibacterial properties against Escherichia coli and Staphylococcus aureus, photothermal disinfection, and thermal insulation performance. Furthermore, the as‐prepared NF@Ag air filters can be simply patterned and designed as respiration monitoring sensors to precisely detect the respiratory activity and health of the human being. Therefore, it is believed that these multifunctional air filters will have good potential for applications in the removal of particular matters and breathable wearable electronic devices. [ABSTRACT FROM AUTHOR]

The pursuit of highly permeable thin‐film nanocomposite (TFNC) nanofiltration (NF) membranes with desirable selectivity is an eternal topic for desalination and wastewater treatment. Herein, a facile route to engineer polyamide (PA) NF membranes is reported with a coral‐reef‐like thin PA active layer atop a polydopamine pre‐decorated ethylene vinyl alcohol copolymer (EVOH) nanofiber scaffold (EVOH‐PDA) via interfacial polymerization (IP). EVOH‐PDA possesses a submicron pore size and super‐hydrophilic surface, which provides abundant thin water layers covering nanofibers in the IP process resulting in the PA layer with a morphology of coral‐reef‐like highland surrounded by flat low‐lying regions. The resultant NF membrane presents high permeance of 32.19 L m−2h−1bar−1 and high rejection of 96.52% to 1000 ppm Na2SO4 feed solution with a stable performance against operation time and high salt concentration. This work provides a new approach to fabricating PA TFNC membranes with outstanding NF performance in liquid separation applications. [ABSTRACT FROM AUTHOR]

Due to the fast degradation time and low storage temperature of nucleic acid, a simple, fast, and highly efficient adsorption process is imperious for the extraction of nucleic acid molecules. In this article, a poly(vinyl alcohol‐co‐ethylene) (EVOH) nanofiber‐based and polyethyleneimine (PEI)‐modified chitosan (ENPC) aerogel with high static adsorption capacity of RNA and DNA molecules (812 and 867 mg g−1, respectively) is proved for enormous potential in adsorption capacity for nucleic acid extraction. A relation between adsorption capacity and the physical morphology of ENPC aerogel membrane is demonstrated with the controllable factors such as chemical components, freeze‐drying temperature, pH value of the nucleic acid solution, and membrane density. The mechanism of the anion‐exchange adsorption process of nucleic acid is analyzed and fitted well with the pseudo‐second‐order kinetic model and Langmuir isotherm (monolayer adsorption). The as‐obtained ENPC aerogel in the form of a membrane with self‐cleaning and flexible properties can be easily tailored and widely utilized in a convenient and efficient extraction process of nucleic acids in both industrial and experimental levels. [ABSTRACT FROM AUTHOR]

Engineering 3D nanofibrous monolithic materials with a controllable porous channel structure and chemical activity is promising for the rapid and efficient separation of environmentally sensitive biomacromolecules such as RNA. Herein, freeze‐drying method via regulating the viscosity of nanofiber dispersions is developed to fabricate nanofibrous sponges (NFSs) with 3D structures of microsphere, lamella, and honeycomb by combining poly(vinyl alcohol‐co‐ethylene) (PVA‐co‐PE) nanofibers with chitosan (CS) and polyethyleneimine (PEI) in dispersions. Among sponges, a honeycomb nanofibrous sponge (HNFS) possesses highly oriented open‐cells and optimal performance, including water permeability of 7.431 × 103 L h m−2 at 1 psi, static saturated capacity of 887.6 mg g−1, dynamic capacity of 763.2 mg g−1 at a flow rate of 1 mm min−1, and mechanical robustness, superior to reported state‐of‐the‐art ion‐exchange chromatography materials. Furthermore, HNFS‐packed chromatographic, funnel, and centrifugal columns present exceptional performance and broad applicability in rapid‐separation of RNA from model solution and diverse organisms without degradation. They are attributed to the highly oriented open‐cell structure and high‐density adsorption ligands on the surface of nanofibrous cell walls. This work provides a facile approach to design advanced NFSs with versatile physicochemical structure and outstanding performance. [ABSTRACT FROM AUTHOR]

To explain the observed phenomenon that most SARS‐CoV‐2 transmission occurs indoors whereas its outdoor transmission is rare, a simple macroscopic aerosol balance model is developed to link short‐ and long‐range airborne transmission. The model considers the involvement of exhaled droplets with initial diameter ≤50 µm in the short‐range airborne route, whereas only a fraction of these droplets with an initial diameter within 15 µm or equivalently a final diameter within 5 µm considered in the long‐range airborne route. One surprising finding is that the room ventilation rate significantly affects the short‐range airborne route, in contrast to traditional belief. When the ventilation rate in a room is insufficient, the airborne infection risks due to both short‐ and long‐range transmission are high. A ventilation rate of 10 L/s per person provides a similar concentration vs distance decay profile to that in outdoor settings, which provides additional justification for the widely adopted ventilation standard of 10 L/s per person. The newly obtained data do not support the basic assumption in the existing ventilation standard ASHRAE 62.1 (2019) that the required people outdoor air rate is constant if the standard is used directly for respiratory infection control. Instead, it is necessary to increase the ventilation rate when the physical distance between people is less than approximately 2 m. [ABSTRACT FROM AUTHOR]

A visible‐light‐irradiated reductive hydrodediazoniation of arenediazonium tetrafluoroborates in THF is described. The reaction proceeded at ambient temperature under catalyst‐ and additive‐free conditions to afford hydrodediazoniated products in good yields. This protocol was also suitable for deuterodediazoniation of arenediazonium tetrafluoroborates in THF‐d8, supplying the corresponding deuterated arenes in excellent yields. Advantages of this dediazoniation strategy include mildness, simplicity, visible‐light irradiation, a wide range of substrates, good functional group tolerance, with no use of catalysts and additives, and feasibility of a one‐pot diazotization/hydrodediazoniation process, which allows for a safe and convenient way to (deuterated)arenes from anilines. [ABSTRACT FROM AUTHOR]

A convenient method for deoxyfluorination of aromatic and aliphatic carboxylic acids with CF3SO2OCF3 in the presence of a suitable base at room temperature has been developed. The reaction allows a straightforward access to a variety of acyl fluorides and proves that CF3SO2OCF3 is an effective deoxyfluorination reagent for carboxylic acids. The method features simplicity, expeditiousness, high efficiency, ease of handling, good functional group tolerance, a wide range of substrates, excellent yields of products, compatibility of many amine initiators, use of environmentally friendly reagents, and effortless removal of byproducts. This reaction represents the first utilization of trifluoromethyl trifluoromethanesulfonate as a fluorination reagent. [ABSTRACT FROM AUTHOR]

This review summarizes the progress in the fluorination and fluoroalkylation of electron‐rich systems with diverse fluorine (F) and fluoroalkyl (Rfn) reagents employing hypervalent iodine compounds as initiators in the last few decades. Because of the strong electrophilicity, high oxidizing properties, low toxicity, air and moisture stability, ready availability, ease of handling, and mild reaction conditions, the hypervalent iodine reagents have been widely utilized in modern organic chemistry. In particular, the use of hypervalent iodine reagents to initiate the C−F and C−Rfn (Rfn=CF2H, CF3, perfluoroalkyl, OCH2CF3, SCF3, SeCF3 and etc) bond formation has been increasingly developed. In these reactions, hypervalent iodine compounds behave as powerful oxidants or electrophiles and activate the fluorination/fluoroalkylation reagents, the transition‐metal catalysts, or the substrates to in situ form electrophilic or radical intermediates, which subsequently participate in fluorination, difluoromethylation, trifluoromethylation, perfluoroalkylation, trifluoroethoxylation, fluoroalkylthiolation, trifluoromethylselenolation and others under mild conditions. Although great achievements have been made in this area, they are just the initial phase and still require a wide scope for improvement. It is anticipated that this review will draw much attention from the organic chemistry community and inspire more contributions in the development of new hypervalent‐iodine‐mediated fluorination and fluoroalkylation reactions. [ABSTRACT FROM AUTHOR]

Progress in the transition‐metal‐catalyzed or ‐free fluoroalkylation of diazo compounds with different types of fluoroalkyl (Rfn) transfer reagents is summarized in this review. Special attention is focused on the straightforward trifluoromethylation, gem‐difluoroolefination, trifluoromethoxylation, fluoroalkylthiolation, and trifluoromethylselenolation of diazo substrates. The mechanistic insights and the application of some of the products are also discussed in this article. We believe that this review will inspire both young and experienced chemists to further study the direct fluoroalkylation of diazo compounds as an efficient and convenient way to build complex fluorine‐containing molecules. [ABSTRACT FROM AUTHOR]

Partial discharge (PD) characteristics of the transformer oil contaminated by metallic particles are relevant to particle movement. The motion characteristics of the particles will change when the oil flows, and hence, the PD characteristics differ from that in stationary oil. In this study, the PD characteristics were investigated at direct current voltages, and the particle trajectories were observed simultaneously. It was found that the number of discharges obviously decreased, but the discharge magnitude slightly increased as the oil flow speed increased. To explain the changes in the PD characteristics, a solid-liquid two-phase flow model was established to simulate the trajectories and the electric field distribution around particles. The experimental observations partially verified the simulated trajectories, which includes two stages, namely sedimentation and the subsequent oscillation-collision stage. With the increase of the flow speed, the sedimentation particles decreased, and the horizontal spacing between two adjacent particle-electrode collisions elongated. Therefore, the total collisions became infrequent, which reduced the number of discharges. Moreover, the higher the flow speed was, the slower the particle approached an electrode. Considering the discharge time lag, the distance between the particle and the electrode at the instant of the PD would increase, which increased the discharge magnitude. [ABSTRACT FROM AUTHOR]

A mild and efficient protocol for O‐arylation of alcohols and phenols (ROH) by triarylsulfonium triflates was developed under transition‐metal‐free conditions. Various alcohols, including primary, secondary and tertiary, and phenols bearing either electron‐donating or electron‐withdrawing groups on the aryl rings were smoothly converted to form the corresponding aromatic ethers in moderate to excellent yields. The reactions were conducted at 50 or 80 °C for 24 h in the presence of a certain base and showed good functional group tolerance. The base‐mediated arylation with asymmetric triarylsulfonium salts could selectively transfer the aryl groups of sulfoniums to ROH, depending on their inherent electronic nature. The mechanistic studies revealed that the reaction might proceed through the nucleophilic attack of the in situ formed alkoxy or phenoxy anions at the aromatic carbon atoms of the C−S bonds of triarylsulfonium cations to furnish the target products. [ABSTRACT FROM AUTHOR]

Trifluoromethyl trifluoromethanesulfonate has proved to be an excellent reservoir of difluorophosgene and a promising click ligation for amines in the preparation of urea derivatives, heterocycles, and carbamoyl fluorides under metal‐ and additive‐free conditions. The reactions are rapid, efficient, selective, and versatile, and can be performed in benign solvents, giving products in excellent yields with minimal efforts for purification. The characteristics of the reactions meet the requirements of a click reaction. The use of trifluoromethyl trifluoromethanesulfonate as a click reagent is advantageous over other "CO" sources (e.g. TsOCF3, PhCO2CF3, CsOCF3, AgOCF3, and triphosgene) because this reagent is readily accessible; easy to scale up; and highly reactive, even under metal‐ and additive‐free conditions. It is anticipated that CF3SO3CF3 will be increasingly as important as SO2F2 as a click agent in future drug design and development. [ABSTRACT FROM AUTHOR]

The present study was designed to elucidate the beneficial effects of XJEK on myocardial infarction (MI) in rats, especially through the amelioration of endothelial dysfunction (ED). 136 Sprague-Dawley rats were randomized into 13 groups: control group for 0wk (n = 8); sham groups for 2, 4, and 6 weeks (wk); MI groups for 2, 4, and 6 wk; MI+XJEK groups for 2, 4, and 6w k; MI+Fosinopril groups for 2, 4, and 6 wk (n = 8~10). In addition, 8 rats were treated for Evans blue staining and Tetrazolium chloride (TTC) staining to determine the infarct size. Cardiac function, ECG, and cardiac morphological changes were examined. Colorimetric analysis was employed to detect nitric oxide (NO), and enzyme-linked immunosorbent assay (ELISA) was applied to determine N-terminal probrain natriuretic peptide (NT-ProBNP), endothelin-1 (ET-1), angiotensin II (Ang II), asymmetric dimethylarginine (ADMA), tetrahydrobiopterin (BH4), and endothelial NO synthase (eNOS) content. The total eNOS and eNOS dimer/(dimer+monomer) ratios in cardiac tissues were detected by Western blot. We found that administration of XJEK markedly ameliorated cardiovascular remodeling (CR), which was manifested by decreased HW/BW ratio, CSA, and less collagen deposition after MI. XJEK administration also improved cardiac function by significant inhibition of the increased hemodynamic parameters in the early stage and by suppression of the decreased hemodynamic parameters later on. XJEK also continuously suppressed the increased NT-ProBNP content in the serum of MI rats. XJEK improved ED with stimulated eNOS activities, as well as upregulated NO levels, BH4 content, and eNOS dimer/(dimer+monomer) ratio in the cardiac tissues. XJEK downregulated ET-1, Ang II, and ADMA content obviously compared to sham group. In conclusion, XJEK may exert the protective effects on MI rats and could continuously ameliorate ED and reverse CR with the progression of MI over time. [ABSTRACT FROM AUTHOR]

Circulating tumor cells (CTCs) play a key role in cancer metastasis but are very difficult to detect. in vivo monitoring CTCs has been recognized as an important technique for cancer research and clinical diagnosis. Recently, a noninvasive method, in vivo flow cytometry (IVFC) has been developed to enable continuous, real‐time, and long‐duration detection of CTCs in animal models by detecting CTC fluorescence in blood vessels excited by lasers. In this study, we present a simple optical scheme for direct noninvasive CTC detection using confocal microscopes. We demonstrate that line scanning of confocal microscopy can provide effective and quantitative CTC detection in live mice during cancer development. Rare CTC signals can be acquired at the early stage of the tumor development after implantation of subcutaneous tumor and monitored continuously to the end. Signals from CTC clusters can also be acquired and distinguished from single CTCs. Our results suggest confocal microscopy is a simple and reliable method for biologists and doctors to use for cancer research. © 2018 International Society for Advancement of Cytometry [ABSTRACT FROM AUTHOR]

Reactions of a dimeric [(bzq)Pd(OAc)]2 complex (1 a′) and mesityl(2,2,2‐trifluoroethyl)iodonium triflate (2 a) with or without additives at room temperature gave 10‐(2,2,2‐trifluoroethyl)benzo[h]quinoline rapidly in moderate to high yields. The reaction might proceed through a unstable binuclear "PdIII−CH2CF3" intermediate (I), which was likely formed in situ from the oxidative addition of 2 a to [(bzq)Pd(OAc)]2 and favorably transformed to mononuclear "(bzq)PdIV−CH2CF3" complexes (III) in the presence of another equiv.alent of 2 a and a suitable additive. Based on these, a Pd‐catalyzed C−H trifluoroethylation of benzo[h]quinolines with 2 a was developed. Numerous benzo[h]quinoline derivatives reacted with [MesICH2CF3][OTf] at room temperature in the presence of 10 mol% Pd(OAc)2 and 2 equiv.. NaHCO3 to provide the corresponding 10‐trifluoroethylated products in excellent yields. [ABSTRACT FROM AUTHOR]

We consider a posteriori error estimation for a multipoint flux mixed finite element method for two‐dimensional elliptic interface problems. Within the class of modified quasi‐monotonically distributed coefficients, we derive a residual‐type a posteriori error estimator of the weighted sum of the scalar and flux errors which is robust with respect to the jumps of the coefficients. Moreover, we develop robust implicit and explicit recovery‐type estimators through gradient recovery in an H(curl)‐conforming finite element space. In particular, we apply a modified L2 projection in the implicit recovery procedure so as to reduce the computational cost of the recovered gradient. Numerical experiments confirm the theoretical results. [ABSTRACT FROM AUTHOR]

In this study, two types of samples, i.e. a disc-shaped cavity embedded within solid dielectrics and the other on an electrode surface, were used to investigate partial discharge (PD) behaviours at DC voltage. It has been found that the discharge frequency of the sample with one metallic surface was much larger under a positive voltage than under a negative one, whereas it was not sensitive to voltage polarities for the sample with two insulating surfaces. In order to explain experimental results, a simulation model based on continuity equations was established to obtain PD sequences at DC voltage, in which surface charge decay and discharge time lag were taken into account. Simulation results showed that positive surface charges dissipated faster than the negative, and the discharge time lag kept almost unchanged at the same voltage amplitude. The discharge time interval consisted of field recovery time and discharge time lag, and the former was determined by surface charge decay rate. In terms of these, the effect of surface charge decay on discharge frequency was discussed. The research is helpful to clarify PD mechanism at DC voltage. [ABSTRACT FROM AUTHOR]

A transition‐metal‐free strategy using organic thiocyanate as a source of ArS or RS moiety allowed a facile and efficient synthesis of bis(tris)‐vinyl sulfides and alkynyl thioethers under mild conditions. The types of thiocyanates and the choice of bases and solvents had significant effects on the outcomes of the reactions. Aryl thiocyanates reacted with terminal arylalkynes in DMF in the presence of t‐BuOK or MOH (M=Cs, K, Na) at room temperature to form (Z)‐1,2‐diarylthio‐1‐arylalkenes in 24–93% yields, while the same reactions with alkyl thiocyanates provided alkyl alkynyl sulfides in 40–96% yields. Using NaH instead of t‐BuOK or MOH as a base in the similar reactions of aryl thiocyanates and terminal arylalkynes led to the formation of (2‐arylethene‐1,1,2‐triyl)tris(arylsulfane)s in 33–85% yields. Varying the solvent from DMF to THF, the reactions of aryl thiocyanates with terminal arylalkynes at −78 °C to room temperature in the presence of t‐BuOK supplied aryl alkynyl sulfides in 34–96% yields. Aryl and alkyl selenocyanates were also suitable substrates in these reactions. This work is the first time transition‐metal‐free selective construction of (Z)‐1,2‐diarylthio‐1‐arylalkenes, (2‐arylethene‐1,1,2‐triyl)tris(arylsulfane), and alkynyl sulfides from organic thiocyanates and terminal arylalkynes in the presence of a certain base. A mild and base‐mediated selective synthesis of (Z)‐1,2‐diarylthio‐1‐arylalkenes, (2‐arylethene‐1,1,2‐triyl)tris(arylsulfane)s and alkynyl sulfides from organic thiocyanates and terminal arylalkynes under transition‐metal‐free conditions is described. [ABSTRACT FROM AUTHOR]

Statistical characteristics of discharge magnitude are significant for insulation diagnosis by monitoring partial discharge (PD) in power apparatuses. However, hitherto, investigations on the PD magnitude distribution in SF6 gas under direct current voltage are insufficient. A current pulse measuring circuit and a ultra-high-frequency (UHF) antenna were simultaneously employed to investigate characteristics of positive corona in 0.3 MPa SF6 gas. It is found that compared to the UHF antenna, the common measurement impedance used in laboratories caused several current pulses overlapped, resulting in pulse burst phenomenon. The pulse burst was easily mistaken as a single PD, which actually contained several PDs, thereby negatively affecting obtaining a real discharge magnitude distribution. Moreover, the discharge magnitude distributions were compared when a pulse burst was treated as a single PD and several PDs, respectively. It is found the former and latter one had forms of non-skewed two-parameter Weibull distribution with large-scale parameters and positively skewed two-parameter Weibull distribution with small-scale parameters, respectively. Based on this understanding, the change of the distributions with time was investigated, and the results showed that the distribution would have a permanent form of two-parameter Weibull distribution after a 24-h transition time. [ABSTRACT FROM AUTHOR]

Abstract: A simple and efficient method for transition‐metal‐free N‐arylation of various amines by triarylsulfonium triflates is described. Both aliphatic and aromatic amines were smoothly converted at 80 °C in the presence of tBuOK or KOH to give the corresponding mono N‐arylated products in good to high yields. The molar ratios of the reactants and the choice of bases had a big effect on the reaction. When a large excess of [Ph3S][OTf] and tBuOK were employed for primary amines under the standard conditions, the bis(N‐phenyl) products were predominantly formed. This method was also applicable to the synthesis of bioactive N‐phenyl amino acid derivatives. The control experiments, the deuterium labelling study, and the presence of regioisomers of N‐arylated products when using 4‐substituted triarylsulfonium triflates suggested that the reaction might proceed through an aryne intermediate. The present protocol demonstrated that triarylsulfonium salts are versatile arylation reagents in the construction of CAr−N bonds. [ABSTRACT FROM AUTHOR]

Abstract: Aplastic anaemia (AA) is a life‐threatening hematopoietic disorder characterized by hypoplasia and pancytopenia with increasing fat cells in the bone marrow (BM). The BM‐derived mesenchymal stem cells (MSCs) from AA are more susceptible to be induced into adipogenic differentiation compared with that from control, which may be causatively associated with the fatty BM and defective hematopoiesis of AA. Here in this study, we first demonstrated that levamisole displayed a significant suppressive effect on the in vitro adipogenic differentiation of AA BM‐MSCs. Mechanistic investigation revealed that levamisole could increase the expression of ZFP36L1 which was subsequently demonstrated to function as a negative regulator of adipogenic differentiation of AA BM‐MSCs through lentivirus‐mediated ZFP36L1 knock‐down and overexpression assay. Peroxisome proliferator‐activated receptor gamma coactivator 1 beta (PPARGC1B) whose 3′‐untranslated region bears adenine‐uridine‐rich elements was verified as a direct downstream target of ZFP36L1, and knock‐down of PPARGC1B impaired the adipogenesis of AA BM‐MSCs. Collectively, our work demonstrated that ZFP36L1‐mediated post‐transcriptional control of PPARGC1B expression underlies the suppressive effect of levamisole on the adipogenic differentiation of AA BM‐MSCs, which not only provides novel therapeutic targets for alleviating the BM fatty phenomenon of AA patients, but also lays the theoretical and experimental foundation for the clinical application of levamisole in AA therapy. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of Grape Seed Proanthocyanidins (GSP) on Nω-Nitro-L-arginine methyl ester-induced hypertension in pregnant mice. Fifty Kunming mice were randomized into control, control + GSP, model, and model + GSP. Three weeks later, the artery systolic blood pressure was examined and the related pathological changes were detected. Aorta relaxation function was assessed by aorta ring apparatus. Blood urea nitrogen and serum creatinine were measured by an automatic biochemistry analyzer. Colorimetric analysis, enzyme-linked immunosorbent assay, immunofluorescence, and western blot were applied to detect related indicator in serum, cardiac, and kidney tissues. The results showed that GSP treatment for 3 weeks could improve cardiovascular and kidney remodeling indexes and decrease blood urea nitrogen and serum creatinine content in serum, as well as could ameliorate oxidative stress status and endothelial dysfunction. Therefore, it is for the first time found that GSP exerts protective effect against Nω-Nitro-L-arginine methyl ester-induced hypertension in pregnant mice, which provided a theoretical basis for potential application in the clinic. [ABSTRACT FROM AUTHOR]

Visible and near-infrared light responsed Sn1-xBixS2nanosheets was synthesised via a simple hydrothermal method. Rhodamine B was adopted to evaluate the degradation efficiency of the as-prepared samples. Experimental results showed that the doping content of Bi3+ could obviously affect the degradation efficiency of SnS2. It was first increased and then decreased with increasing the Bi3+ content under the visible light irradiation. When the mole fraction of doping Bi3+ was 5%, the as-prepared Sn0.95Bi0.05S2 with a bandgap of 0.38 eV had the highest degradation efficiency of 95.9% in 120 min. Moreover, the as-prepared composites possessed more effective electron-hole pair separation than that of pure SnS2. In addition, a possible degradation mechanism of the as-prepared Sn0.95Bi0.05S2 was proposed. [ABSTRACT FROM AUTHOR]

Reductive trifluoromethylation of aromatic a-diazo esters at room temperature with the Yagupolskii-Umemoto reagent {[Ph2SCF3][OTf ]; (2a)} in DMF in the presence of excess CuCl gave a variety of a-trifluoromethyl arylacetates in up to 93 % yield. The prior reaction of 2a with CuCl before the addition of the α-diazo esters was imperative for the conversion. This initial reaction might pregenerate the key [CuICF3] intermediate, according to the results of our control experiments. When the long-chain perfluoroalkyl diphenylsulfonium triflates 2b-2e were used instead of 2a, the reaction of an aromatic α-diazo ester under the same conditions followed by treatment with NaHCO3 gave a series of fluorinated α,β-unsaturated esters in good yields. This protocol gives a facile, convenient, and practical access to α-trifluoromethyl arylacetates and their analogues, implying that the "+Rfn" reagents are compatible with α-diazo esters in the presence of an appropriate reductant. [ABSTRACT FROM AUTHOR]

An additive- and transition metal-free perfluoroalkanesulfonylation of alkynyl(phenyl)iodonium tosylates with sodium perfluoroalkanesulfinates (RfnSO2Na) is described. The poorly nucleophilic RfnSO2Na reacted with alkynyl(phenyl)iodonium salts in dichloromethane at room temperature under a nitrogen atmosphere for 5-60 minutes to afford a variety of acetylenic triflones and alkynyl perfluoroalkyl sulfones in good to quantitative yields. The position of substituents on the phenyl rings of the arylethynyl moiety in the iodonium salts had a big influence on the reaction. The formation of five-membered cyclic vinyl sulfones suggested that the reaction proceeds via an alkylidene carbene intermediate. Furthermore, successful scaling-up of the reaction demonstrates the practicality of the new method. Advantages of the method include short reaction times, mild conditions, and the easy access to perfluoroalkanesulfonylation reagents (RfnSO2Na). [ABSTRACT FROM AUTHOR]

A Pd-catalyzed Suzuki cross-coupling of arylboronic acids with Yagupolskii-Umemoto reagents was explored. In contrary to trifluoromethylations, the Pd-catalyzed reaction of R−B(OH)2 and [Ar2SCF3]+[OTf]− provided the arylation products (R−Ar) in good to high yields. The reaction confirms that the S−Ar bonds of [Ar2SCF3]+[OTf]− can be readily cleaved in the presence of Pd complexes. The relatively electron-poor aryl groups of asymmetric [Ar1Ar2SCF3]+[OTf]− salts are more favorably transferred compared to the electron-rich ones. This reaction represents the first report of utilization of [Ar2SCF3]+[OTf]− as arylation reagents in organic synthesis. [ABSTRACT FROM AUTHOR]

Aim The goal of the present study was to determine the disparities in prevalence and risk factors of loneliness between rural empty nest and non-empty nest older adults in Chizhou, China. Methods A sample of 730 participants (381 empty nest older adults and 349 non-empty nest older adults) were surveyed using the University of California at Los Angeles- Loneliness Scale, the 30-item Geriatric Depression Scale ( GDS-30), the Pittsburgh Sleep Quality Index, the Social Support Rate Scale, the Perceived Social Support from Family Scale and the World Health Organization Quality of Life questionnaire abbreviated version. Results The present study showed that the mean level of loneliness did significantly differ between empty nest older adults and non-empty nest older adults (41.52 ± 6.98 vs 39.46 ± 7.38). Empty nesters had significantly higher GDS scores; by contrast, they received lower objective, subjective and family support. Family support, objective support and social interaction were associated significantly with loneliness, which was more pronounced in empty nest older adults, excluding subjective support and psychological domain. The GDS scores (β = 0.237, P < 0.001) and age (β = −0.114, P = 0.002) showed stronger significant associations with loneliness in empty nest older adults. Conclusions Loneliness obviously prevails among empty nest older adults than non-empty nest older adults. Depressive symptoms showed a stronger risk of empty nest older adults being lonely. Family support was suggested as a protective factor for loneliness in both groups. These findings should be considered when developing intervention strategies to reduce loneliness. Geriatr Gerontol Int 2015; 15: 356-364. [ABSTRACT FROM AUTHOR]

Based on potential theory, Steklov eigensolutions of elastic problems can be converted into eigenvalue problems of boundary integral equations (BIEs). The kernels of these BIEs are characterized by logarithmic and Hilbert singularities. In this article, the Nyström methods are presented for obtaining eigensolutions (λ( i), u( i)), which have to deal with the two kinds of singularities simultaneously. The solutions possess high accuracy orders O( h3) and an asymptotic error expansion with odd powers. Using h3 -Richardson extrapolation algorithms, we can greatly improve the accuracy orders to O( h5). Furthermore, a generalized Fourier series is constructed by the eigensolutions, and then solving the elasticity displacement and traction problems involves just calculating the coefficients of the series. A class of elasticity problems with boundary Γ is solved with high convergence rate O( h5). The efficiency is illustrated by a numerical example. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2012 [ABSTRACT FROM AUTHOR]

Eur J Clin Invest 2012; 42 (5): 517-525 Abstract Background Hepcidin plays a central role in iron homeostasis, which is regulated by iron stores, the rate of erythropoiesis, inflammation, and hypoxia. Aberrant expression of hepcidin was found in many diseases, however, there is scant information on hepcidin expression in acute leukemia (AL). Materials and methods 32 patients with AL which diagnosis according to FAB criteria were studied. Serum hepcidin levels, erythropoietin (EPO), interleukin-6 (IL-6), hematological parameters, intracellular and extracellular iron store were evaluated. Results Hepcidin was elevated significantly with increased iron storage in patients at onset of AL when erythropoiesis was depressed by blast cells, then decreased significantly with AL remission, while soluble transferrin receptor (sTfR) concentration was elevated. Negative correlations were found between serum hepcidin and erythropoietic markers including RBC, Hb, Ret and sTfR. Positive correlations were shown between hepcidin and ferritin, between hepcidin and ratio of sideroblasts, as well as between hepcidin and IL-6. Conclusions Hepcidin production was regulated by iron stores, inflammation and erythropoietic activity in AL patients. Erythropoietic activity may play the main role among the regulators of hepcidin expresssion. [ABSTRACT FROM AUTHOR]

The synthesis of alkynyl trifluoromethyl selenoethers from copper‐mediated aerobic decarboxylative trifluoromethylselenolation of alkynyl carboxylic acids with [Me4N][SeCF3] is reported. The reaction proceeded smoothly under mild conditions and enabled the facile conversion of both aryl and alkyl alkynyl carboxylic acids to the corresponding trifluoromethyl selenoethers in good yields, demonstrating that decarboxylative trifluoromethylselenolation of alkynyl carboxylic acids with the nucleophilic [Me4N][SeCF3] reagent is feasible at ambient temperature without irradiation. Advantages of the method include the use of bench‐stable and non‐volatile alkynyl carboxylic acids as starting materials, readily accessible SeCF3 reagent, excellent functional group tolerance, and the avoidance of harsh reaction conditions. This copper‐mediated reaction represents the first decarboxylative trifluoromethylselenolation of alkynyl carboxylic acids with a SeCF3 source. [ABSTRACT FROM AUTHOR]

In order to study the tissue-specific expression of rabbit apotipoprotein (apo) A-I, a 923-base-pair clone, pRBA-502, complementary to rabbit apo A-I mRNA was identified from a rabbit intestinal cDNA library by hybrideselect translation and imrnunoprecipitation methods. Northern blot and dot-blot hybridization, utilizing 32P-labeled pRBA-502, revealed that the rabbit apo A-I gene is expressed in the intestine, not in the liver and that rabbit apo A4 mRNA is about 950 nucleotides in length. The entire nucleotide sequence of pRBA-502 has been determined and the complete amino acid sequence of the corresponding apo A-I has been deduced. The mRNA codes for a protein comprising 265 amino acids. Amino acids 1-18 and 19-24 of the primary translation product represent the presegment and prosegment, respectively, of apo A-I. Matured rabbit apo A-i contains 241 amino acids and has a molecular mass of 27612 Da. Using pRBA-502 as a probe, a 15.5-kb genomic fragment, which contains the entire apo A-1 gene, was isolated from a rabbit liver genomic library. Sequence analysis of the gene shows that the 200 base pairs of the 5' upstream flanking region of the rabbit and human apo A-I genes showed 78% sequence homology. Like the human ape A-I gene, the rabbit apo A-I gene is interrupted by three intervening sequences. Except for two nucleotides in the fourth exon, the coding sequence of the rabbit liver apo A-I gene is identical to that of pRBA-502. Our data showed that the Lack of expression of ape A-I gene in rabbit liver is not due to the alternation of rabbit liver ape A-I gene sequence and suggest that the expression of ape A-I gene in rabbit liver is regulated by a trans-acting regulating element(s). [ABSTRACT FROM AUTHOR]

Partial sequence comparisons have recently indicated that two extracellular components, fibulin from human placenta and BM-90 from a basement-membrane-producing mouse tumor, are either identical or closely related proteins. In this study, a completer sequence analysis of mouse BM-90 cDNA showed a 539-residue N-terminal core structure (domains I and II), which was 85% identical with the same core structure of human fibulin. A t37-redisue C-terminal sequence (domain III) was unique for BM-90 and could also be identified for the mouse tumor. A second 117-residue C-terminal sequence (domain III) was identified in additional mouse cDNA clones and showed 91% identity with the region specific for variant C of fibulin. Northern blots using mouse cells demonstrated two mRNA species. 2.7 kb and 2.3 kb, which encoded the variants D and C, respectively. The sequence of BM-90/fibulin indicates the presence of nine epidermal-growth-factor-like repeats in the core domain-II structure, eight of which contain consensus motifs for calcium binding. This binding is apparently important for the interaction of BM-90 was demonstrated to fibronectin and BM-90 itself, but did not depend on calcium. Major binding sites for Bm-90 were identified at a C-terminal segment of laminin A chain and at the N-terminus of nidogen. The broad interaction repertoire of BM-90 is comparable to that of nidogen and both proteins may have similar roles as connecting elements in the extracellular matrix. [ABSTRACT FROM AUTHOR]

The article discusses the metal-organic frameworks of a three-dimensional pillared-layer structure that encapsulates a water chain of (H20)12 clusters. The crystal structure using the single-crystal X-ray diffraction reveals that compound (I) is monoclinic and crystallizes in the centro-symmetric space group. The geometry of hydrogen bond is presented in a table. A figure showing the local coordination of a silver atom, showing the atomic numbering scheme is also presented.

A novel design of a slotted triangular microstrip antenna for dual-frequency operation is proposed and experimentally studied. By embedding an inverted V-shaped slot close to the vertex of a triangular microstrip patch, dual-frequency operation of the microstrip antenna can be achieved using an inset microstrip-line feed. The two operating frequencies have parallel polarization planes and broadside radiation characteristics. Also, the frequency ratio, in the range 1.37–1.59, of the two frequencies can be controlled by the length of the embedded slot. Details of the obtained dual-frequency performances are presented and discussed. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 318–320, 2000. [ABSTRACT FROM AUTHOR]

Constructing macroscopic materials with optimal surface structure to immobilize silver nanoparticles polluted in water environment and further maximize their practical functionality still remains a great challenge. An infrequent strategy is developed to build a flexible material system combining PVA‐co‐PE nanofiber membrane (NFM) scaffold and mussel‐inspired polydopamine (PDA), which provides a formidable surface interacting with polyethyleneimine (PEI). The resultant PEI/PDA/NFM presents an ultrahigh adsorption capacity (727.8 mg g−1) to citrate‐capped silver nanoparticles much higher than the values reported in the literatures. The broad applicability of the multifunctional composite membranes in water treatment is further demonstrated. Interestingly, a promising concurrent performance of antibacterial, antifouling, and catalysis is acquired in bacterial filtrations. Benefiting from the structure, a plasma process further enhances the catalytic performance of AgNPs‐PEI/PDA/NFM with an ultrahigh turnover frequency value: 6.65 × 10−1 mol mol−1 min−1, which facilitates the fast degradation treatment of p‐nitrophenol (p‐NP) in continuous‐flow filtration. The excellent properties can be rationally assigned to the optimized surface structure synergistically determined by the high specific area of porous nanofiber scaffold and high substrate adaptability of reactive polydopamine. This implies the superiority of membranes obtained by present strategy in recycling Ag NPs contaminant and further applies it in fast‐efficient wastewater treatment applications. A superhigh‐capability immobilized Ag nanoparticle is achieved by synergistical optimization of surface structure in PVA‐co‐PE nanofiber scaffold and polydopamine materials system. The resultant flexible porous composite membrane presents fast and recycled catalysis performance after oxygen plasma treatment, implying superiority in the related environmental treatment. [ABSTRACT FROM AUTHOR]

Trifluoromethyl trifluoromethanesulfonate has proved to be an excellent reservoir of difluorophosgene and a promising click ligation for amines in the preparation of urea derivatives, heterocycles, and carbamoyl fluorides under metal‐ and additive‐free conditions. The reactions are rapid, efficient, selective, and versatile, and can be performed in benign solvents, giving products in excellent yields with minimal efforts for purification. The characteristics of the reactions meet the requirements of a click reaction. The use of trifluoromethyl trifluoromethanesulfonate as a click reagent is advantageous over other "CO" sources (e.g. TsOCF3, PhCO2CF3, CsOCF3, AgOCF3, and triphosgene) because this reagent is readily accessible; easy to scale up; and highly reactive, even under metal‐ and additive‐free conditions. It is anticipated that CF3SO3CF3 will be increasingly as important as SO2F2 as a click agent in future drug design and development. [ABSTRACT FROM AUTHOR]