Solid-liquid Two-phase Flow Numerical Simulation around Guide Vanes of Mixed-flow Water Turbine

AbstractBased on the N-S control equation and κ-ɛ-Ap turbulent model, the solid-liquid two-phase flow field around the guide vanes of a mixed-flow water turbine was simulated. The solid-liquid two-phase flow characters around the guide vanes were analyzed on the design work condition with different volume fraction and particles diameter of solid phase. The effects of the solid particles diameter and volume fraction on the flow around the guide vane are discussed, based on which the prediction and analysis of abrasion and cavitation properties on the guiding device were given. The prediction results were identical with the test date, which can provide reference on the abrasion prediction and optimal design of guide vane

Projected Spatiotemporal Dynamics of Drought under Global Warming in Central Asia

Drought, one of the most common natural disasters that have the greatest impact on human social life, has been extremely challenging to accurately assess and predict. With global warming, it has become more important to make accurate drought predictions and assessments. In this study, based on climate model data provided by the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), we used the Palmer Drought Severity Index (PDSI) to analyze and project drought characteristics and their trends under two global warming scenarios—1.5 °C and 2.0 °C—in Central Asia. The results showed a marked decline in the PDSI in Central Asia under the influence of global warming, indicating that the drought situation in Central Asia would further worsen under both warming scenarios. Under the 1.5 °C warming scenario, the PDSI in Central Asia decreased first and then increased, and the change time was around 2080, while the PDSI values showed a continuous decline after 2025 in the 2.0 °C warming scenario. Under the two warming scenarios, the spatial characteristics of dry and wet areas in Central Asia are projected to change significantly in the future. In the 1.5 °C warming scenario, the frequency of drought and the proportion of arid areas in Central Asia were significantly higher than those under the 2.0 °C warming scenario. Using the Thornthwaite (TH) formula to calculate the PDSI produced an overestimation of drought, and the Penman–Monteith (PM) formula is therefore recommended to calculate the index

Microfluidic Chip for Non-Invasive Analysis of Tumor Cells Interaction with Anti-Cancer Drug Doxorubicin by AFM and Raman Spectroscopy

Raman spectroscopy has been playing an increasingly significant role for cell classification. Here, we introduce a novel microfluidic chip for non-invasive Raman cell natural fingerprint collection. Traditional Raman spectroscopy measurement of the cells grown in a Polydimethylsiloxane (PDMS) based microfluidic device suffers from the background noise from the substrate materials of PDMS when intended to apply as an in vitro cell assay. To overcome this disadvantage, the current device is designed with a middle layer of PDMS layer sandwiched by two MgF2slides which minimize the PDMS background signal in Raman measurement. Three cancer cell lines, including a human lung cancer cell A549, and human breast cancer cell lines MDA-MB-231 and MDA-MB-231/BRMS1, were cultured in this microdevice separately for a period of three days to evaluate the biocompatibility of the microfluidic system. In addition, atomic force microscopy (AFM) was used to measure the Young\u27s modulus and adhesion force of cancer cells at single cell level. The AFM results indicated that our microchannel environment did not seem to alter the cell biomechanical properties. The biochemical responses of cancer cells exposed to anti-cancer drug doxorubicin (DOX) up to 24 h were assessed by Raman spectroscopy. Principal component analysis over the Raman spectra indicated that cancer cells untreated and treated with DOX can be distinguished. This PDMS microfluidic device offers a non-invasive and reusable tool for in vitro Raman measurement of living cells, and can be potentially applied for anti-cancer drug screening

A Multi-Scale Approach to Study Biochemical and Biophysical Aspects of Resveratrol on Diesel Exhaust Particle-Human Primary Lung Cell Interaction

Diesel exhaust particles (DEPs) are major air pollutants that lead to numerous human disorders, especially pulmonary diseases, partly through the induction of oxidative stress. Resveratrol is a polyphenol that ameliorates the production of reactive oxygen species (ROS) and delays aging-related processes. Herein we studied the cytoprotective effect of resveratrol on DEP-exposed human lung cells in a factorial experimental design. This work investigates biophysical features including cellular compositions and biomechanical properties, which were measured at the single-cell level using confocal Raman microspectroscopy (RM) and atomic force microscopy (AFM), respectively. Principal component analysis (PCA), hierarchical cluster analysis (HCA) and partial least square regression (PLS) analysis were applied to analyze Raman spectra with and without resveratrol protection. The health status of individual cells could be effectively predicted using an index derived from characteristic Raman spectral peak (e.g., 1006 cm−1) based on PLS model. AFM measurements indicated that cellular adhesion force was greatly reduced, while Young’s modulus was highly elevated in resveratrol treated DEP-exposed cells. Anti-oxidant resveratrol reduced DEP-induced ROS production and suppressed releases of several cytokines and chemokines. These findings suggest resveratrol may enhance resistance of human lung cells (e.g., SAEC) to air pollutants (e.g. DEPs)

Utjecaj sastava podloge na povećanje biomase micelija i proizvodnje egzopolimera s pomoću gljive Hericium erinaceus CZ-2

In this work, the effects of medium composition and fermentation parameters on the simultaneous production of mycelial biomass and exopolymer by medicinal mushroom Hericium erinaceus CZ-2 were investigated in shake flask cultures using one-factor-at-a-time method and orthogonal array design. Results showed that the most suitable carbon, nitrogen, mineral sources, and cofactors for the mycelial biomass and exopolymer production were: corn flour combined with 1 % glucose, yeast extract, KH2PO4 and corn steep liquor. The intuitive analysis of orthogonal array design results indicated that the effects of nutritional requirement on the mycelial growth of Hericium erinaceus CZ-2 were in regular sequence of corn flour combined with 1 % glucose > yeast extract > corn steep liquor > KH2PO4, and those on exopolymer production were in the order of corn flour combined with glucose > KH2PO4 > yeast extract > corn steep liquor. The maximal yield of mycelial biomass (16.07 g/L) was obtained when the composition of the culture medium was (in g/L): corn flour 30, glucose 10, yeast extract 3, KH2PO4 1, CaCO3 0.5, and 15 mL/L of corn steep liquor; while the maximal exopolymer yield (1.314 g/L) was achieved when the composition of medium was (in g/L): corn flour 30, glucose 10, yeast extract 5, KH2PO4 3, CaCO3 0.5, and 15 mL/L of corn steep liquor. In the 15-litre scale-up fermentation, the maximum mycelial biomass yield of 20.50 g/L was achieved using the optimized medium.U ovom je radu ispitan utjecaj sastava podloge i uvjeta fermentacije na istodobnu proizvodnju biomase micelija i egzopolimera s pomoću ljekovite gljive Hericium erinaceus CZ-2. Pokusi su provedeni na kulturama uzgojenim na tresilici, primjenom jednofaktorske metode i ortogonalnog modela. Rezultati su pokazali da su najbolji izvori dušika, minerala i kofaktora za proizvodnju biomase micelija i egzopolimera kukuruzno brašno s 1 % glukoze, ekstrakt kvasca, KH2PO4 i kukuruzni ekstrakt. Analizom ortogonalnog modela utvrđeno je da na povećanje micelija redom utječu: kukuruzno brašno s 1 % glukoze, zatim ekstrakt kvasca, kukuruzni ekstrakt i KH2PO4, a na proizvodnju egzopolimera kukuruzno brašno s glukozom, zatim KH2PO4, ekstrakt kvasca te kukuruzni ekstrakt. Najveći je prinos biomase micelija (16,07 g/L) postignut s ovim sastavom podloge (u g/L): kukuruzno brašno 30, glukoza 10, ekstrakt kvasca 3, KH2PO4 1, CaCO3 0,5 i 15 mL/L kukuruznog ekstrakta, a najveći je prinos egzopolimera (1,314 g/L) dobiven korištenjem podloge (u g/L) od: kukuruznog brašna 30, glukoze 10, ekstrakta kvasca 5, KH2PO4 3, CaCO3 0,5 i 15 mL/L kukuruznog ekstrakta. Povećanjem obujma fermentacije na 15 L dobiven je najveći prinos biomase micelija od 20,50 g/L pri optimalnim uvjetima

Photon upconversion through triplet exciton-mediated energy relay.

Exploration of upconversion luminescence from lanthanide emitters through energy migration has profound implications for fundamental research and technology development. However, energy migration-mediated upconversion requires stringent experimental conditions, such as high power excitation and special migratory ions in the host lattice, imposing selection constraints on lanthanide emitters. Here we demonstrate photon upconversion of diverse lanthanide emitters by harnessing triplet exciton-mediated energy relay. Compared with gadolinium-based systems, this energy relay is less dependent on excitation power and enhances the emission intensity of Tb3+ by 158-fold. Mechanistic investigations reveal that emission enhancement is attributable to strong coupling between lanthanides and surface molecules, which enables fast triplet generation (<100 ps) and subsequent near-unity triplet transfer efficiency from surface ligands to lanthanides. Moreover, the energy relay approach supports long-distance energy transfer and allows upconversion modulation in microstructures. These findings enhance fundamental understanding of energy transfer at molecule-nanoparticle interfaces and open exciting avenues for developing hybrid, high-performance optical materials

Tunable hysteresis effect for perovskite solar cells

Perovskite solar cells (PSCs) usually suffer from a hysteresis effect in current–voltage measurements, which leads to an inaccurate estimation of the device e fficiency. Although ion migration, charge trapping/ detrapping, and accumulation have been proposed as a b asis for the hysteresis, the origin of the hysteresis has not been apparently unraveled. Herein we reporte d a tunable hysteresis effect based uniquely on open- circuit voltage variations in printable mesos copic PSCs with a simplified triple-layer TiO 2 /ZrO 2 /carbon architecture. The electrons are collected by the compact TiO 2 /mesoporous TiO 2 (c-TiO 2 /mp-TiO 2 )bilayer, and the holes are collected by the carbon layer. By adj usting the spray deposition cycles for the c-TiO 2 layer andUV-ozonetreatment,weachievedhysteresis-norm al, hysteresis-free, and hysteresis-inverted PSCs. Such unique trends of tunable hysteresis are anal yzed by considering the polarization of the TiO 2 /perovskite interface, which can accumulate positive charges reversibly. Successfully tuning of the hysteresis effect clarifies the critical importance of the c-TiO 2 /perovskite interface in controlling the hysteretic trends observed, providing important insights towards the understanding of this rapidly developing photovoltaic technology

Poverty alleviation in developing and underdeveloped countries. Do foreign capital and economic freedom matter?

Our study focuses on the role of foreign capital which includes foreign direct investment, foreign aid, and economic freedom in poverty alleviation in developing and underdeveloped countries by using panel data from 1995 to 2018 for 71 countries. In the pursuit of achieving our objective, we employed several econometric techniques such as dynamic ordinary least square, fully modified ordinary least square, dynamic fixed effect, and pooled mean group regression methods. Furthermore, we performed the Granger causality test, impulse response function, and variance decomposition analysis. In our long-run estimations, we found that foreign direct investment could significantly alleviate poverty but increases poverty in the short run. Instead, foreign aid plays no significant role in poverty alleviation. Moreover, economic growth and economic freedom are essential as our findings consistently exhibited that they play a crucial role in poverty alleviation. We also found bidirectional causality between poverty alleviation and population growth, while a unidirectional causal linkage was found from poverty alleviation to foreign aid. We conclude that policymakers should look at a new paradigm of developmental assistance, and governments should also create an aiding environment for foreign investment to support their growth plan. First published online 13 December 202