68 research outputs found
Curcumin inhibits proliferation and metastasis of human hypopharyngeal carcinoma cells
The present study was designed to investigate the effects of curcumin, a natural product derived from turmeric of the herb Curcuma longa, on proliferation, metastasis of FaDu cells, and the relevant mechanisms. Results showed that curcumin could inhibit the proliferation, induce apoptosis of FaDu cells, and arrest the cell-cycle at S phases in a dose-dependent manner. The ability of FaDu cells in migration and invasion was declined significantly after treated with curcumin. Additionally, caspase-9 and caspase-3 were activated, and the expression of Bax and E-cadherin were up-regulated, whereas, the expressions of Bcl-2, MMP-2 and MMP-9 were down-regulated in response to curcumin. In conclusion, these data suggested that curcumin can effectively suppress proliferation and inhibit the invasion and metastasis of FaDu cells via the induction of apoptosis, the blockage of cell cycle as well as the modulation of certain relevant genes.Colegio de Farmacéuticos de la Provincia de Buenos Aire
Electric field control of deterministic current-induced magnetization switching in a hybrid ferromagnetic/ferroelectric structure
All-electrical and programmable manipulations of ferromagnetic bits are highly pursued for the aim of high integration and low energy consumption in modern information technology1, 2, 3. Methods based on the spin–orbit torque switching4, 5, 6 in heavy metal/ferromagnet structures have been proposed with magnetic field7, 8, 9, 10, 11, 12, 13, 14, 15, and are heading toward deterministic switching without external magnetic field16, 17. Here we demonstrate that an in-plane effective magnetic field can be induced by an electric field without breaking the symmetry of the structure of the thin film, and realize the deterministic magnetization switching in a hybrid ferromagnetic/ferroelectric structure with Pt/Co/Ni/Co/Pt layers on PMN-PT substrate. The effective magnetic field can be reversed by changing the direction of the applied electric field on the PMN-PT substrate, which fully replaces the controllability function of the external magnetic field. The electric field is found to generate an additional spin–orbit torque on the CoNiCo magnets, which is confirmed by macrospin calculations and micromagnetic simulations
Activating Transcription Factor 4 Confers a Multidrug Resistance Phenotype to Gastric Cancer Cells through Transactivation of SIRT1 Expression
BACKGROUND: Multidrug resistance (MDR) in gastric cancer remains a major challenge to clinical treatment. Activating transcription factor 4 (ATF4) is a stress response gene involved in homeostasis and cellular protection. However, the expression and function of ATF4 in gastric cancer MDR remains unknown. In this study, we investigate whether ATF4 play a role in gastric cancer MDR and its potential mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated that ATF4 overexpression confered the MDR phenotype to gastric cancer cells, while knockdown of ATF4 in the MDR variants induced re-sensitization. In this study we also showed that the NAD(+)-dependent histone deacetylase SIRT1 was required for ATF4-induced MDR effect in gastric cancer cells. We demonstrated that ATF4 facilitated MDR in gastric cancer cells through direct binding to the SIRT1 promoter, resulting in SIRT1 up-regulation. Significantly, inhibition of SIRT1 by small interfering RNA (siRNA) or a specific inhibitor (EX-527) reintroduced therapeutic sensitivity. Also, an increased Bcl-2/Bax ratio and MDR1 expression level were found in ATF4-overexpressing cells. CONCLUSIONS/SIGNIFICANCE: We showed that ATF4 had a key role in the regulation of MDR in gastric cancer cells in response to chemotherapy and these findings suggest that targeting ATF4 could relieve therapeutic resistance in gastric cancer
Impact of Seat Inclination and Misalignment on Airborne Pollutant Transport in a Single-Aisle Aircraft Cabin
Airborne pollutant transport in an aircraft cabin is greatly affected by the created airflow. The seat layout can impact the flow and thus the pollutant transport. Most studies have adopted symmetric upright seats for simplicity. The influence of seat inclination and seat misalignment on airflow and pollutant transport is still unclear. This investigation adopted a validated computational fluid dynamics (CFD) method to study the airflow and airborne pollutant distribution in a single-aisle cabin with seven rows of seats. The pollutant was assumed to be released from a passenger seated in the middle of three adjacent seats. A total of five different seat layouts were considered, including all of the upright seats, the inclination of three adjacent seats, the inclination of all of the seats in half a cabin, the inclination of all of the seats in a whole cabin, and the misalignment seat rows across the aisle. The flows in both the cross and longitudinal sections were compared. The pollutant concentrations in the respiratory zone of the passengers in different seats were adopted to evaluate the cross-contamination. The results revealed that the symmetric seat layout aids to circumscribe the released pollutant in a small region and reduces the cross-contamination either by maintaining the upright seats or inclining all of the seats. Contrarily, any inclination of seats or a misalignment of seat rows should be avoided during the pandemic since an asymmetric seat layout would generate asymmetric flow and strengthen the spreading of pollutants
Soil Aggregates Are Governed by Spacing Configurations in Alfalfa-Jujube Tree Intercropping Systems
Soil aggregates play an important role in affecting the structural stability of the soil, and it is important to understand the relationship between soil aggregate stability and crop yield in herbage-fruit tree intercropping systems. In this study, we determined the optimal spacing configurations for improving aggregate stability while increasing crop yields in alfalfa-jujube intercropping systems. The treatments included three intercropping patterns, i.e., the distances between alfalfa and jujube at 0.5 m (IP0.5m), 1 m (IP1m), and 1.45 m (IP1.45m), along with monoculture alfalfa (CKAL) and jujube (CKJU). The results showed that IP0.5m, IP1m, IP1.45m, and CKJU effectively improved soil aggregate structure compared to CKAL. The IP1m spacing significantly increased the amounts of macro-aggregates (8.2%), and improved soil mechanical properties and aggregate stability among the other treatments, which was partly attributable to increased mean weight diameter (13.6%) and decreased soil aggregate destruction rate of water-stable aggregates (2.9%). The results of the principal component analysis showed that IP1m treatments had a positive effect on PC1. The one-meter spacing of jujube-to-alfalfa intercropping optimized the soil structure while improving the yield (8.3%); thus, it can be considered the most suitable intercropping spacing configuration for growing alfalfa in jujube plantations
Rhenium(I) complex as an electron acceptor in a photovoltaic device
An organic photovoltaic (PV) device with a structure of indium-tin-oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (20 nm)/4,4′,4′′-tris[3-methylphenyl (phenyl)amino]triphenylamine (m-MTDATA) (30 nm)/Re(CO)3Cl-monophenanthroline (Re-Phen) (60 nm)/LiF (1 nm)/Al (100 nm) has been fabricated. When the device was irradiated by 365 nm ultraviolet (UV) light, open circuit voltage (Voc) of 1.15 V, the short circuit current (Isc) of 100 μA/cm2, fill factor (FF) of 0.45 and power conversion efficiency of 4% were obtained, respectively. Spectroscopic investigation evidenced that the increase in the PV efficiency is related to the existence of a charge transfer absorption process. The generation mechanism of the PV effect was discussed. © 2006 Elsevier B.V. All rights reserved
Metal-organic framework DUT-67 (Zr) for adsorptive removal of trace Hg2+ and CH3Hg+ in water
A Zr-based stable metal-organic frameworks DUT-67 (Zr) was successfully synthesized as an adsorbent to remove trace mercury and methylmercury ions in aqueous solution. The removal efficiency of 90% and 55% of Hg2+ and CH3Hg+ was respectively achieved at pH 6 and 55°C. The S in thiophene has a relatively weak adsorption capacity for mercury and there could be the slight π-complexation between thiophere ring of DUT-67 (Zr) and Hg2+ besides physical absorption, while there only was physical adsorption between DUT-67 (Zr) and CH3Hg+. The developed methods were applied to remove trace Hg2+ and CH3Hg+ in the real water samples, and the removal efficiency was from 69% to 90% and from 30% to 77% respectively; when the concentrations of Hg2+ was lower than 20 μg L−1 in the samples, the remaining mercury concentration was lower than 1 μg L−1,which can meet the standard of the World Health Organization
The α Adrenoceptor Agonist and Sedative/Anaesthetic Dexmedetomidine Excites Diverse Neuronal Types in the Ventrolateral Preoptic Area of Male Mice
The unique sedative activities with rapid arousal of dexmedetomidine (Dex) are not fully understood. Growing evidence suggests the involvement of the ventrolateral preoptic area (VLPO) in sleep–wake cycle. The major type in the VLPO is sleep-active neurons, inhibited by noradrenaline (NA(−) neurons). The other type of neurons is activated by NA (NA(+) neurons), which are wake-active. Previous research showed that Dex-induced sedation and sleep homeostasis likely share common mechanisms. To explore the underlying mechanisms of Dex in the VLPO, in vivo polysomnography recording and in vitro electrophysiological recording were used in our study. Bath application of Dex (2 μM) increased the firing rate of both VLPO NA(−) and NA(+) neurons. Compared to the control group, there was no difference in the firing rate of both VLPO NA(−) and NA(+) neurons after Dex (2 μM) and RS79948 (1 mM) administration, an α 2 receptor antagonist. No difference was detected regarding resting membrane potential (RMP) amplitude of both VLPO NA (−) and NA(+) neurons after application of Dex (2 μM). Moreover, Dex (2 μM) significantly reduced the frequency of miniature inhibitory postsynaptic currents (mIPSCs) in both VLPO NA(−) and NA(+) neurons. These electrophysiology results were consistent with behavioral sedation, with increased nonrapid eye movement sleep (NREM sleep) and increased expression of c-Fos in the VLPO during the dark phase after intraperitoneal injection with Dex (80 μg/kg). In conclusion, Dex activates NA(−) and NA(+) neurons in the VLPO via presynaptic α 2 receptors. This mechanism may explain the unique sedative properties with rapid arousal. Summary Statement Dexmedetomidine is an important ICU sedative. The mechanism of dexmedetomidine is not fully understood. Activating NA(−) and NA(+) neurons in the VLPO by dexmedetomidine using polysomnography and electrophysiological recording, this may explain the unique sedative properties with rapid arousal
Possible Role of Mitochondrial Transfer RNA Gene 5816 A > G Genetic Polymorphism (m.5816A > G) in a 3-Year-Old Child with Dystonia: Report of a Case
Background Mutations in the mitochondrial transfer RNA (mt-tRNA) gene are a hotspot for mitochondrial DNA (mtDNA) mutations and are most common in mitochondrial diseases
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