Activation of p38/HSP27 pathway counters melatonin-induced inhibitory effect on proliferation of human gastric cancer cells

Overexpression of heat shock protein 27(HSP27)in gastric cancer is correlated with poor clinical prognosis.Melatonin,an endogenous hormone,shows promise in gastric cancer therapy.However,there is limited study on the biological activity of HSP27 in response to melatonin treatment.In this study,we show an anti-proliferative action of melatonin on human gastric cancer cell lines BGC-823 and MGC-803.Biochemically,the inhibitory effect of melatonin is accompanied by the upregulation of HSP27 phosphorylation level.Transfection of gastric cancer cells with HSP27-specific siRNA effectively reduces HSP27 phosphorylation and potentiated melatonininduced inhibitory effect on cell proliferation.The reduction of cyclin D1 in melatonin-treated cells is also aggravated by HSP27 depletion.Moreover,melatonin stimulation increases p38 phosphorylation.Pretreatment with p38 inhibitor SB203580 not only remarkably suppresses melatonin-induced HSP27 phosphorylation,but also augment the inhibitory effect of melatonin on cyclin D1 expression as well as cell proliferation.Taken together,our study indicates the protective pathway of p38/HSP27 against melatonin-induced inhibitory effect on gastric cancer cell proliferation,suggesting that combined with p38/HSP27 pathway inhibitor,the therapeutic efficacy of melatonin on gastric cancer may be improved.

A Proton Nuclear Magnetic Resonance (¹H NMR) Investigation of NaCl-Induced Phase Separation of Acetonitrile-Water Mixtures

The microscopic properties of NaCl-induced phase separation of acetonitrile (ACN)-water mixtures have been studied by proton nuclear magnetic resonance (1H NMR). Acetonitrile-rich phase increases with increasing NaCl concentration (cNaCl) at xACN ≈ 0.25. 1H chemical shift of water for acetonitrile-rich phase rapidly decreases with decreasing NaCl mole concentration and that for water-rich phase quickly increases with increasing cNaCl. However, 1H chemical shift of acetonitrile has nothing to do with the molar concentration of NaCl, and it keeps relatively stable for all solutions (±0.002). These results reveal that Na+ and Cl- are rapidly hydrated by water, not by acetonitrile. The change of 1H chemical shift of water has shown that the number of hydrogen bond increases or hydrogen bond strengths with increasing NaCl molarity in mixtures. But hydrogen bond is broken or weaken with the temperature rising. 1H chemical shifts of pure water and the water in acetonitrile-rich phase have been investigated at 293 K, 298 K and 303 K. The hydration number of Na+ (6.05) in water-rich phase is determined by an empirical equation involving 1H chemical shift, temperature and NaCl molarity, which is in good agreement with the literatures.

Reconfigurable logic and in-sensor encryption operations in an asymmetrically tunable van der Waals heterostructure

Reconfigurable devices can be used to achieve multiple logic operation and intelligent optical sensing with low power consumption,which is promising candidates for new generation electronic and optoelectronic integrated circuits.However,the versatility is still limited and need to be extended by the device architectures design.Here,we report an asymmetrically gate two-dimensional(2D)van der Waals heterostructure with hybrid dielectric layer SiO_(2)/hexagonal boron nitride(h-BN),which enable rich function including reconfigurable logic operation and in-sensor information encryption enabled by both volatile and non-volatile optoelectrical modulation.When the partial gate is grounded,the non-volatile light assisted electrostatic doping endowed partially reconfigurable doping between n-type and p-type,which allow the switching of logic XOR and not implication(NIMP).When the global gate is grounded,additionally taking the optical signal as another input signal,logic AND and OR is realized by combined regulation of the light and localized gate voltage.Depending on the high on/off current ratio approaching 105 and reliable&switchable logic gate,in-sensor information encryption and decryption is demonstrated by manipulating the logic output.Hence,these results provide strong extension for current reconfigurable electronic and optoelectronic devices.

p-/n-Type modulation of 2D transition metal dichalcogenides for electronic and optoelectronic devices

Two-dimensional layered transition metal dichalcogenides(TMDCs)have demonstrated a huge potential in the broad fields of optoelectronic devices,logic electronics,electronic integration,as well as neural networks.To take full advantage of TMDC characteristics and efficiently design the device structures,one of the most key processes is to control their p-/n-type modulation.In this review,we summarize the p-/n-type modulation of TMDCs based on diverse strategies consisting of intrinsic defect tailoring,substitutional doping,surface charge transfer,chemical intercalation,electrostatic modulation,and dielectric interface engineering.The modulation mechanisms and comparisons of these strategies are analyzed together with a discussion of their corresponding device applications in electronics and optoelectronics.Finally,challenges and outlooks for p-/n-type modulation of TMDCs are presented to provide references for future studies.

Growth of centimeter scale Nb_(1−x)W_(x)Se_(2) monolayer film by promoter assisted liquid phase chemical vapor deposition

Two-dimensional(2D)transition-metal dichalcogenide materials(TMDs)alloys have a wide range of applications in the field of optoelectronics due to their capacity to achieve wide modulation of the band gap with fully tunable compositions.However,it is still a challenge for growing alloys with uniform components and large lateral size due to the random distribution of the crystal nucleus locations.Here,we applied a simple but effective promoter assisted liquid phase chemical vapor deposition(CVD)method,in which the quantity ratio of promoter to metal precursor can be controlled precisely,leading to tiny amounts of transition metal oxide precursors deposition onto the substrates in a highly uniform and reproducible manner,which can effectively control the uniform distribution of element components and nucleation sites.By this method,a series of monolayer Nb_(1−x)W_(x)Se_(2)alloy films with fully tunable compositions and centimeter scale have been successfully synthesized on sapphire substrates.This controllable approach opens a new way to produce large area and uniform 2D alloy film,which has the potential for the construction of optoelectronic devices with tailored spectral responses.

A review on transesterification of propylene carbonate and methanol for dimethyl carbonate synthesis

Dimethyl carbonate(DMC)is widely applied in various fields according to its outstanding physico-chemical properties,especially as a solvent in electrolyte of lithium-ion batteries.More than 90%DMC in China is industrially produced from the propylene carbonate(PC)and methanol(MeOH)route because it is an environmentally friendly and highly efficient process.This review summarizes different DMC production technologies,homogeneous and heterogeneous catalysts,catalytic mechanisms,reaction kinetics and engineering,with particular focus on the relationship between catalyst preparation and catalytic performances.The advantages and disadvantages of various catalysts are categorically compared.Homogeneous catalysts are highly efficient but prone to deactivate and are difficult to separate.Heterogeneous catalysts are easy to separate and have the promising future in industrial application,but their low catalytic efficiency is still the critical bottleneck.From process aspect,the catalytic distillation technology would be promising to overcome the efficiency problem of solid catalysts.

Carrier mobility tuning of MoS_(2) by strain engineering in CVD growth process

Strain engineering is proposed to be an effective technology to tune the properties of two-dimensional(2D)transition metal dichalcogenides(TMDCs).Conventional strain engineering techniques(e.g.,mechanical bending,heating)cannot conserve strain due to their dependence on external action,which thereby limits the application in electronics.In addition,the theoretically predicted strain-induced tuning of electrical performance of TMDCs has not been experimentally proved yet.Here,a facile but effective approach is proposed to retain and tune the biaxial tensile strain in monolayer MoS_(2) by adjusting the process of the chemical vapor deposition(CVD).To prove the feasibility of this method,the strain formation model of CVD grown MoS_(2) is proposed which is supported by the calculated strain dependence of band gap via the density functional theory(DFT).Next,the electrical properties tuning of strained monolayer MoS_(2) is demonstrated in experiment,where the carrier mobility of MoS_(2) was increased by two orders(~0.15 to~23 cm^(2)·V^(−1)·s^(−1)).The proposed pathway of strain preservation and regulation will open up the optics application of strain engineering and the fabrication of high performance electronic devices in 2D materials.