As a promising energy converter, the requirement for miniaturization and high-accuracy of triboelectric nanogenerators always remains urgent. In this work, a micro triboelectric ultrasonic device was ...developed by integrating a triboelectric nanogenerator and micro-electro-mechanical systems technology. To date, it sets a world record for the smallest triboelectric device, with a 50 µm-sized diaphragm, and enables the working frequency to be brought to megahertz. This dramatically improves the miniaturization and chip integration of the triboelectric nanogenerator. With 63 kPa@1 MHz ultrasound input, the micro triboelectric ultrasonic device can generate the voltage signal of 16.8 mV and 12.7 mV through oil and sound-attenuation medium, respectively. It also achieved the signal-to-ratio of 20.54 dB and exhibited the practical potential for signal communication by modulating the incident ultrasound. Finally, detailed optimization approaches have also been proposed to further improve the output power of the micro triboelectric ultrasonic device.
The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by ...coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.
Dysregulated microRNAs (miRNAs) have an important role in many malignant tumors. However, elucidating the roles of miRNAs in cancer biology, especially in epithelial cancers, remains an ongoing ...process. In this study, we show that both miR-143 and miR-145, which belong to the same miRNA cluster, can negatively modulate expression of their target gene, MDM2. The miR-143 and miR-145 is posttranscriptionally activated by upregulated p53, thereby generating a short miRNAs-MDM2-p53 feedback loop. Re-expression of these miRNAs suppresses cellular growth and triggers the apoptosis of epithelial cancer, in vitro and in vivo, by enhancing p53 activity via MDM2 turnover. Moreover, the miRNA-dependent MDM2 turnover contributes to the equilibrium of repeated p53 pulses in response to DNA damage stress. These findings suggest that MDM2 dysregulation caused by downregulation of miR-143 and miR-145 contributes to epithelial cancer development and has a key role in regulating cellular proliferation and apoptosis. Re-expression of miR-143 and miR-145 may be a reasonable strategy for treatment of epithelial cancers.
Avermectins are major antiparasitic agents used commercially in animal health, agriculture and human infections. To improve the fermentation efficiency of avermectins, for the first time a plasma jet ...generated by a novel atmospheric pressure glow discharge (APGD) was employed to generate mutations in Streptomyces avermitilis. The APGD plasma jet, driven by a radio frequency (RF) power supply with water-cooled and bare-metallic electrodes, was used as a new mutation method to treat the spores of S. avermitilis. The plasma jet yielded high total (over 30%) and positive (about 21%) mutation rates on S. avermitilis, and a mutated strain, designated as G1-1 with high productivity of avermectin B1a and genetic stability, was obtained. Because of the low jet temperature, the high concentrations of the chemically reactive species and the flexibility of its operation, the RF APGD plasma jet has a strong mutagenic effect on S. avermitilis. This is a proof-of-concept study for the use of an RF APGD plasma jet for inducing mutations in microbes. We have shown that the RF APGD plasma jet could be developed as a promising and convenient mutation tool for the fermentation industry and for use in biotechnology research.
Graphene‐based organic nanocomposites have ascended as promising candidates for thermoelectric energy conversion. In order to adopt existing scalable printing methods for developing thermostable ...graphene‐based thermoelectric devices, optimization of both the material ink and the thermoelectric properties of the resulting films are required. Here, inkjet‐printed large‐area flexible graphene thin films with outstanding thermoelectric properties are reported. The thermal and electronic transport properties of the films reveal the so‐called phonon‐glass electron‐crystal character (i.e., electrical transport behavior akin to that of few‐layer graphene flakes with quenched thermal transport arising from the disordered nanoporous structure). As a result, the all‐graphene films show a room‐temperature thermoelectric power factor of 18.7 µW m−1 K−2, representing over a threefold improvement to previous solution‐processed all‐graphene structures. The demonstration of inkjet‐printed thermoelectric devices underscores the potential for future flexible, scalable, and low‐cost thermoelectric applications, such as harvesting energy from body heat in wearable applications.
Inkjet printing of large‐scale thermoelectric graphene devices is demonstrated. Stable ink and printing process is achieved for devices with a threefold thermoelectric power factor increase as compared to previously reported solution‐processed all‐graphene devices. The printed thermoelectric device shows remarkable mechanical and thermoelectric stability making it highly suitable for flexible and wearable electronics applications.
Summary
Increased neuropeptide Y (NPY) expression occurred in the glucocorticoid-induced osteoporotic skeleton. NPY knockout mice exhibited a minor response to the glucocorticoid-mediated ...exacerbation of bone accretion and fatty marrow pathogenesis. NPY deletion restored SITR1 signaling and enhanced PPARγ ubiquitination of bone tissue, an alternative strategy for ameliorating glucocorticoid-induced skeletal deterioration.
Introduction
Glucocorticoid excess is observed to worsen the pathogenesis of osteoporosis and fatty marrow. This study was undertaken to investigate the contribution of neuropeptide Y (NPY) to glucocorticoid-induced bone loss and marrow adiposity.
Methods
NPY knockout and wild-type mice were administered methylprednisolone for four consecutive weeks. Bone mineral density, microarchitecture, and calcein-labeled mineral acquisition were quantified by μCT, dual energy X-ray absorptiometry, and histomorphometry. Expression of osteogenic and adipogenic markers and acetylation states of PPARγ were detected by RT-quantitative PCR, immunoprecipitation, and immunoblotting.
Results
High NPY levels were associated with glucocorticoid-induced trabecular bone deterioration and marrow fat accumulation. Mice lacking NPY had high bone mass concomitant with spacious trabecular and cortical bone microstructure. NPY deletion shielded skeletal tissues from the glucocorticoid-induced impediment of bone mass, trabecular morphometric characteristics, mineral accretion activity, and fatty marrow development. Ex vivo, NPY deficiency sustained osteogenic differentiation capacity and curtailed the glucocorticoid-mediated escalation of adipocyte formation reactions of primary bone-marrow mesenchymal cells. NPY deletion appeared to modulate Y1 and Y2 receptors, sirtuin 1, ERK, and p38 signaling pathways, an effect that facilitated hypoacetylation and ubiquitination of adipogenic transcription factor PPARγ in the skeletal tissues exposed to glucocorticoid stress.
Conclusions
NPY mediates the glucocorticoid-induced disturbance of mineral accretion and marrow adipogenesis through post-translational modification of PPARγ. This study brings a new molecular insight into the disintegration of adipogenic and osteogenic activities within glucocorticoid-mediated osteoporotic skeletons. Control of NPY is an alternative strategy to ameliorate glucocorticoid-induced bone destruction and fatty marrow.
Gold nanoparticles have been used for centuries, both for decoration and in medical applications. More recently, many of the major advances in cluster chemistry have involved well-defined clusters ...containing tens or hundreds of atoms, either with or without a ligand shell. In this paper we report the synthesis of two gold/lead clusters, Au
Pb
and Au
Pb
, both of which contain nido Au@Pb
icosahedra surrounding a core of Au atoms. Analogues of these large clusters are not found in the corresponding Ag chemistry: instead, the Ag-centered nido icosahedron, Ag@Pb
, is the only isolated product. The structural chemistry, along with the mass spectrometry which shows the existence of Au
Pb
but not Ag
Pb
, leads us to propose that the former species is the key intermediate in the growth of the larger clusters. Density functional theory indicates that secondary π-type interactions between the Au@Pb
ligands and the gold core play a significant part in stabilizing the larger clusters.
To better understand the impact of a microscopically positive margin (R1) on patterns of disease recurrence and survival after pancreaticoduodenectomy (PD) for pancreatic adenocarcinoma.
A positive ...resection margin after PD is considered to be a poor prognostic factor, and some have proposed that an R1 margin may be a biologic predictor of more aggressive disease. The natural history of patients treated with contemporary multimodality therapy who underwent a positive margin PD has not been described.
We analyzed our experience from 1990 to 2004, which included the prospective use of a standardized system for pathologic analysis of all PD specimens. All patients who underwent PD met objective computed tomographic criteria for resection. Standard pathologic evaluation of the PD specimen included permanent section analysis of the final bile duct, pancreatic, and superior mesenteric artery (SMA) margins. First recurrences (all sites) were defined as local, regional, or distant. Survival and follow-up were calculated from the date of initial histologic diagnosis to the dates of first recurrence or death and last contact, respectively.
PD was performed on 360 consecutive patients with pancreatic adenocarcinoma. Minimum follow-up was 12 months (median, 51.9 months). The resection margins were negative (R0) in 300 patients (83.3%) and positive (R1) in 60 (16.7%); no patients had macroscopically positive (R2) margins. By multivariate analysis (MVA), high mean operative blood loss and large tumor size were independent predictors of an R1 resection. Patients who underwent an R1 resection had a median overall survival of 21.5 months compared with 27.8 months in patients who underwent an R0 resection. After controlling for other variables on MVA, resection status did not independently affect survival. By MVA, only lymph node metastases, major perioperative complications, and blood loss adversely affected survival.
There was no statistically significant difference in patient survival or recurrence based on R status. However, this series is unique in the incorporation of a standardized surgical technique for the SMA dissection, the prospective use of a reproducible system for pathologic evaluation of resection margins, the absence of R2 resections, and the frequent use of multimodality therapy.
Construction and demolition (C&D) waste accounts for a large proportion of solid waste, thus effective C&D waste management is essential for promoting sustainable development. In Hong Kong, the ...government has promulgated a series of policies to encourage related stakeholders to implement effective C&D waste management. However, the overall status remains not satisfactory and has a great potential for further improvement. In this circumstance, the aim of this study is proposing solutions for further improvement of effective C&D waste management in Hong Kong. Based on a comprehensive content analysis of seven selected countries and two rounds of focus group meetings with local experienced professionals, prevailing C&D waste management policies and successful practices were identified and their feasibility of implementation in Hong Kong was discussed. Results revealed that non‐inert waste recycling is a key for improving the C&D waste management in Hong Kong to a higher level. A “3R + I” principle was suggested to be implemented in Hong Kong instead of the currently employed “3R” principle. Four solutions, namely promulgation of more specialized regulations, adoption of advanced recycling technologies, development of mature recycling markets, and implementation of high landfilling costs, were identified as the key directions for future improvement of C&D waste management in Hong Kong. The identified C&D waste management policies and the research methods used in this study can be employed in other countries or regions which are at different C&D waste management levels and economic status to form their own applicable policy framework.
Agriculture is very sensitive to climate change, and correct forecasting of climate change is a great help to accurate allocation of irrigation water. The use of irrigation water is influenced by ...crop water demand and precipitation. Potential evapotranspiration (ET0) is a measure of the ability of the atmosphere to remove water from the surface through the processes of evaporation and transpiration, assuming no control on water supply. It plays an important role in assessing crop water requirements, regional dry–wet conditions, and other factors of water resource management. This study analyzed the spatial and temporal evolution processes and characteristics of major meteorological parameters at 10 stations in the Loess Plateau of northern Shaanxi (LPNS). By using the Mann–Kendall trend test with trend–free pre–whitening and the ArcGIS platform, the potential evapotranspiration of each station was quantified by using the Penman–Monteith equation, and the effects of climatic factors on potential evapotranspiration were assessed by analyzing the contribution rate and sensitivity of the climatic factors. The results showed that the climate in LPNS has become warmer and drier. In terms of the sensitivity of ET0 to the variation of each climatic factor in LPNS, relative humidity (0.65) had the highest sensitivity, followed by daily maximum temperature, wind speed, sunshine hours, and daily minimum temperature (−0.05). In terms of the contribution rate of each factor to ET0, daily maximum temperature (5.16%) had the highest value, followed by daily minimum temperature, sunshine hours, relative humidity, and wind speed (1.14%). This study provides a reference for the management of agricultural water resources and for countermeasures to climate change. According to the climate change and the characteristics of the study area, farmers in the region should increase irrigation to guarantee crop water demand.
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•The Loess Plateau of northern Shaanxi (LPNS) experienced a warmer and drier period.•Sensitivity and contribution rate analysis were used to explore the driving factor of ET0.•ET0 showed a significant upward trend in the northern part of LPNS.•ET0 was most sensitive to the variation of relative humidity in LPNS。•Maximum temperature had a higher contribution rate to the variation of ET0 in LPNS
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