The alkoxy radicals that are derived from cyclic hemiacetals have been generated through the visible‐light‐promoted reaction of the corresponding N‐alkoxyphthalimides with Hantzsch ester as the ...reductant. The alkoxy radicals subsequently undergo β‐scission of the C−C bond to generate carbon‐centered radicals, which are trapped by alkynyl‐, alkenyl‐, or allylsulfones.
Ring‐opening alkynylation, alkenylation, and allylation of cyclic hemiacetal derivatives under visible‐light irradiation conditions with Hantzsch ester (HE) as the reductant have been developed. Photoinduced generation of alkoxy radicals, β‐scission, and the trapping of the generated carbon‐centered radicals by alkynyl‐, alkenyl‐, or allylsulfones are involved in these transformations (see scheme).
Age‐associated obesity and muscle atrophy (sarcopenia) are intimately connected and are reciprocally regulated by adipose tissue and skeletal muscle dysfunction. During ageing, adipose inflammation ...leads to the redistribution of fat to the intra‐abdominal area (visceral fat) and fatty infiltrations in skeletal muscles, resulting in decreased overall strength and functionality. Lipids and their derivatives accumulate both within and between muscle cells, inducing mitochondrial dysfunction, disturbing β‐oxidation of fatty acids, and enhancing reactive oxygen species (ROS) production, leading to lipotoxicity and insulin resistance, as well as enhanced secretion of some pro‐inflammatory cytokines. In turn, these muscle‐secreted cytokines may exacerbate adipose tissue atrophy, support chronic low‐grade inflammation, and establish a vicious cycle of local hyperlipidaemia, insulin resistance, and inflammation that spreads systemically, thus promoting the development of sarcopenic obesity (SO). We call this the metabaging cycle. Patients with SO show an increased risk of systemic insulin resistance, systemic inflammation, associated chronic diseases, and the subsequent progression to full‐blown sarcopenia and even cachexia. Meanwhile in many cardiometabolic diseases, the ostensibly protective effect of obesity in extremely elderly subjects, also known as the ‘obesity paradox’, could possibly be explained by our theory that many elderly subjects with normal body mass index might actually harbour SO to various degrees, before it progresses to full‐blown severe sarcopenia. Our review outlines current knowledge concerning the possible chain of causation between sarcopenia and obesity, proposes a solution to the obesity paradox, and the role of fat mass in ageing.
Tribulus terrestris L. (Zygophyllaceae) (TT) is usually used as a cardiotonic, diuretic, and aphrodisiac, as well as for herbal post-stroke rehabilitation in traditional Chinese medicine. However, ...little is known about the renoprotective effects of TT on obesity-related glomerulopathy (ORG). In this study, 340 monomeric compounds were identified from TT extracts obtained with ethyl acetate combined with 50% methanol. In vitro, IC50 of TT was 912.01 mg/L, and the appropriate concentration of TT against oxidized-low density lipoprotein (ox-LDL) induced human renal glomerular endothelial cells (HRGECs) was 4 mg/L. TT significantly increased the viability (63.2%) and migration (2.33-fold increase) of HRGECs. ORG model rats were induced by a chronic high-fat diet (45%) for 20 weeks and were then treated with TT extract (2.8 g/kg/d) for 8 weeks. Subsequently, the kidneys were removed and their differentially expressed protein profile was identified using two-dimensional electrophoresis coupled with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF)-TOF MS. Molecular categorization and functional analysis of bioinformatic annotation suggested that excessive energy metabolism, decreased response to stress and low immunity were the potential etiologies of ORG. After TT administration for 8 weeks, body weight, blood pressure, serum cystatin C and cholesterol were decreased. Additionally, TT significantly enhanced the resistance of rats to ORG, decreased energy consumption and the hemorrhagic tendency, and improved the response to acute phase reactants and immunity. In conclusion, TT may play a protective role against ORG in rats.
A single-stage 6.78 MHz transmitter is proposed, which directly converts a utility ac input to a regulated, high-frequency (6.78 MHz) ac output for wireless power transmission. The topology ...integrates a totem-pole rectifier operating in a discontinuous conduction mode and an asymmetrical voltage cancellation controlled full-bridge inverter. Compared with the traditional cascaded multistage transmitters, this single-stage approach achieves high power efficiency over the full load range, utilizes fewer fast-switching devices, and shrinks the size of the converter. Constant current behavior at the output of the transmitter enables a fast response to a sudden load change. The operation and theoretical analysis of the single-stage transmitter is verified using a 100 W, GaN-based prototype. Experimental results demonstrate the capability of the converter to provide high power factor, low total harmonic distortion of the input current, and high conversion efficiency over the whole power range. The resulting prototype is suitable for implementation in wireless power systems where multiple consumer electronics loads are charged from a single transmitter.
Purpose - The purpose of this paper is to identify the key convenience dimensions of online shopping, as convenience has been one of the principal motivations underlying customer inclinations to ...adopt online shopping.Design methodology approach - The authors first employ in-depth focus group interviews with online consumers to identify the attributes of online shopping convenience and then develop and validate an instrument of five key dimensions to measure online shopping convenience by analyzing data collected via a Web-based questionnaire survey.Findings - The five dimensions of online shopping convenience are: access, search, evaluation, transaction, and possession post-purchase convenience.Practical implications - Online retailers can employ the five-factor measurement instrument to assess the degree of customer perceived online shopping convenience. This instrument can assist managers in identifying and overcoming key obstacles to the delivery of a highly convenient online shopping service to customers, and also helps them enlarge their loyal customer base.Originality value - This study focuses on uncovering the key dimensions of convenience and their associated sub-dimensions specific to the context of online shopping. Theoretically, the identified dimensions and their related sub-items comprise a validated scale for measuring Web-based service convenience and can serve as building blocks for further studies in e-commerce customer relationship management.
An optimized nanostructure design for high‐power, high‐energy lithium‐ion batteries and supercapacitors is realized by fabricating a nanocomposite with highly dispersed nanoparticles of active ...materials in a nanoporous carbon matrix. A nano‐LiFePO4/nanoporous carbon matrix nanocomposite forms a bridge between a supercapacitor and a battery electrode and offers a reasonable compromise between rate and capacity.
2,4-Dichlorophenoxyacetic acid (2,4-D) is widely used in agriculture as herbicide/pesticide, plant growth regulator and fruit preservative agent. It progressively accumulates in the environment ...including surface water, air and soil. It could be detected in human food and urine, which poses great risk to the living organisms. In the present study, we investigated the developmental toxicity of 2,4-D on zebrafish (Danio rerio) embryo. 2,4-D exposure significantly decreased both the survival rate (LC50 = 46.71 mg/L) and hatching rate (IC50 = 46.26 mg/L) of zebrafish embryos. The most common developmental defect in 2,4-D treated embryos was pericardial edema. 2,4-D (25 mg/L) upregulated marker genes of cardiac development (vmhc, amhc, hand2, vegf, and gata1) and downregulated marker genes of oxidative stress (cat and gpx1a). Whole mount in situ hybridization confirmed the vmhc and amhc upregulation by 2,4-D treatment. LC/MS/MS showed that the bioaccumulation of 2,4-D in zebrafish embryos were increased in a time-dependent manner after 25 mg/L of 2,4-D treatment. Taken together, our study investigated the toxic effects of 2,4-D on zebrafish embryonic development and its potential molecular mechanisms, gave evidence for the full understanding of 2,4-D toxicity on living organisms and shed light on its environmental impact.
•2,4-D caused cardiotoxicity in zebrafish embryos at 25 and 50 mg/L.•2,4-D at 25 mg/L altered the transcriptional levels of several oxidative stress -related genes.•2,4-D at 25 mg/L altered the transcriptional levels of several cardiac-related genes.•2,4-D at 25 mg/L accumulated in zebrafish embryos in a time-dependent manner.
Organic nitrates are broadly applied as pharmaceuticals (acting as efficient nitric oxide donor), energetic materials, building blocks in organic synthesis, etc. However, practical and direct methods ...to access organic nitrates efficiently are still rare, mainly due to the lack of powerful nitrooxylating reagents. Herein, we report bench‐stable and highly reactive noncyclic hypervalent iodine nitrooxylating reagents, oxybis(aryl‐λ3‐iodanediyl) dinitrates (OAIDNs, 2), which are prepared just by using aryliodine diacetate and HNO3. The reagents are used to achieve a mild and operationally simple protocol to access diverse organic nitrates. By employing of 2, zinc‐catalyzed regioselective nitrooxylation of cyclopropyl silyl ethers is realized efficiently to access the corresponding β‐nitrooxy ketones with high functional‐group tolerance. Moreover, a series of direct and catalyst‐free nitrooxylations of enolizable C−H bonds are carried out smoothly to afford the desired organic nitrates within minutes by just mixing the substrates with 2 in dichloromethane.
A bench‐stable and highly reactive noncyclic hypervalent iodine nitrooxylating reagent is prepared from aryliodine diacetate and HNO3. This reagent facilitates the zinc‐catalyzed regioselective nitrooxylation of cyclopropyl silyl ethers with broad scope, and also can be used in the nitrooxylation of various enolizable C−H bonds.
According to the institution-based view, ownership type is a key variable affecting environment-strategy configurations. This study configures the mechanism in which ownership types (as an ...institutional factor) moderate the effect of innovation strategies on firms' innovation performance. An empirical analysis was conducted on Chinese hi-tech manufacturing firms, using information related to the innovation activities of 303 firms. The empirical results suggest that ownership type affects the positive relationship between three sources of innovation (internal R&D activities, partnering with alliance partners, and partnering with universities) and innovation performance, as well as the negative relationship between external contracting and innovation performance (product or process innovation). The results imply that organizations doing business in China must be aware of the business environment that they intend to enter, especially if the intention is to develop new products or innovate current business processes.
Insulin resistance (IR) is the primary pathological mechanism underlying type 2 diabetes mellitus (T2DM). Here, the study aimed to ascertain whether and how exercise mediates IR in T2DM. An in vivo ...mouse model of high-fat diet-induced IR and an in vitro high-glucose-induced IR model were constructed. High long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) expression was detected in T2MD and was positively correlated with HOMA-IR and resistin levels. Then, short hairpin RNA targeting MALAT1 (sh-MALAT1) or pcDNA-MALAT1 was delivered into human umbilical vein endothelial cells (HUVECs) to knock down or upregulate its expression, respectively. Silencing of MALAT1 resulted in reduced levels of resistin, Ang II, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), endothelin-1 (ET-1), and p-insulin receptor substrate-1 (p-IRS)/ISR-1, and decreased cell migration, as well as enhanced glucose uptake and levels of nitric oxide (NO) and p-Akt/Akt. In the IR mouse model, exercise was observed to downregulate MALAT1 to reduce resistin, whereby exercise reduced homeostatic model assessment-insulin resistance (HOMA-IR). Besides, exercise also elevated microRNA-382-3p (miR-382-3p) expression in the serum of IR mice. Dual-luciferase reporter and RNA binding protein immunoprecipitation (RIP) assays identified that MALAT1 could bind to miR-382-3p to upregulate resistin. Collectively, the key observations of the study provide evidence that inhibition of MALAT1 elevates miR-382-3p to repress resistin, which consequently underlies the mechanism of exercise protecting against IR, highlighting a direction for T2DM therapy development.
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