Human immunodeficiency virus (HIV) infection is fast becoming widespread in the world with 37.7 million people living with HIV in 2020. Antiretroviral therapy involving chemical drugs has declined ...acquired immunodeficiency syndrome (AIDS)‐related mortality and improved the life quality of AIDS/HIV sufferers. However, the emergence of drug resistance and side effects are the main obstacles for the long‐term use of these chemicals as antiretroviral therapy. Recently, a lot of emphasis is being put on finding naturally occurring drug candidates that show activity against HIV and can be potentially used as antiretroviral therapy. In this study, different medicinal plants, Pistacia khinjuk, Teucrium stocksianum, Uncaria tomentosa, Pistacia integerrima, Trigonella gharuensis, and Artocarpus lakoocha, were explored for their anti‐HIV potential. Syncytium and p24 assays were performed to determine antiviral activity, while the MTT assay was used to determine cytotoxicity. Results showed that extracts from all six plants inhibited HIV replication in vitro. Also, extracts from Pistacia khinjuk, Teucrium stocksianum, Uncaria tomentosa, and Pistacia integerrima showed low cytotoxicity with a 50% cytotoxicity concentration value of >200 μM. Results of this study indicate that there is potential in these natural extracts to become candidate drugs to be used as complementary and alternative medicine for HIV infection.
Highlights
Important findings with reference to anti‐human immunodeficiency virus (HIV) activities and cytotoxicities of extracts from six different plants.
Extracts from all six plants inhibited HIV replication in vitro.
Pistacia khinjuk (concentration required for the effectiveness of 50% EC50 = 0.34 µM) and Teucrium stocksianum (EC50 = 0.57 µM) showed the highest anti‐HIV activities.
These natural extracts have the potential to become candidate drugs to be used as a complementary and alternative medicine for HIV.
Discovering useful hidden patterns from learner data for online learning systems is valuable in education technology. Studies on personalized learning full-path recommendation are particularly ...important for the development of advanced E-learning systems. In this paper, we present a novel model of full-path learning recommendation. This model relies on clustering and machine learning techniques. Based on a feature similarity metric on learners, we first cluster a collection of learners and train a long short-term memory (LSTM) model in order to predict their learning paths and performance. Personalized learning full-paths are then selected from the results of path prediction. Finally, a suitable learning full-path is recommended specifically to a test learner. In this study, a series of experiments have been carried out against learning resource datasets. By comparisons, experimental results indicate that our proposed methods are able to make sound recommendations on appropriate learning paths with significantly improved learning results in terms of accuracy and efficiency.
Restricted by China’s “hukou” system, the population in any given area of the country is relatively constant, and its employability and workability are mutually determined, as in a closed ecosystem. ...Social capital (or “guanxi” in Chinese society) in China has the effects of reducing set-up costs for entrepreneurship or securing the job-seeking for employment. This paper uses equilibrium analysis and makes some modifications to Kihlstrom and Laffont’s model to explore career choice mechanisms in China’s context. It was found that when social capital only reduces the set-up costs for entrepreneurship, there exists one equilibrium point; individuals with more social capital will choose entrepreneurship, and those with less social capital will be workers or unemployed. When social capital simultaneously reduces the set-up costs for entrepreneurship and secures employment, four equilibrium points appear along with the strength of social capital, and the career options occur in the order of entrepreneurship, employment, entrepreneurship, and unemployment. The findings fill the gap that career choice is mainly determined by an individual’s risk-aversion and contribute specifically to China’s entrepreneurship and employment selection.
High water permeability and good separation property are greatly desired in water production due to energy concerns. To explore nanofiltration (NF) membrane with high permeability for cations ...separation, a positively charged NF membrane was fabricated via interfacial polymerization using polyethersulfone (PES) three-channel capillary ultrafiltration (UF) membrane as substrate, polyethyleneimine (PEI) as the aqueous precursor. The NF membrane preparation conditions were optimized. To enhance the permeability of the prepared NF membrane, modified hydroxyl contained multi-walled carbon nanotubes (MWCNTs-OH), grafting with piperazine (PIP), were utilized. The resultant NF membrane showed increased water flux from 20.8L·m−2·h−1 to 56.1L·m−2·h−1 at 4bar after adding 0.01wt% modified MWCNTs-OH in aqueous solution. Interestingly, MgCl2 rejection of the membrane also increased from 94.2% to 96.9%. The positively charged NF membrane exhibited above 97% rejection for divalent cations (Mg2+ and Ca2+) and low rejection (<70%) for monovalent cations (Na+ and Li+), and it also showed long durability and good separation for Mg2+ and Li+ when the membrane was used to separate mixed salts solution simulated the composition of salt lake brine. The fabricated membrane would have potential for effective water softening and for reclamation of lithium from brine or seawater with high Mg2+/Li+ ratio.
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•MWCNTs-OH was modified by grafting with PIP.•Tri-pores positively charged NF membrane was fabricated with modified MWCNTs in aqueous solution.•The prepared NF membrane showed highly improved permeability and good separation for Mg2+ and Li+.
Battery pack performance is the main concern for electric vehicles and energy storage systems. However, charge imbalance is inevitable due to inconsistent manufacturing techniques and environmental ...conditions. Charge imbalance reduces the power performance and available energy of battery packs. Hence, it is necessary to perform battery equalization. This article proposes an active equalization circuit and a novel equalization strategy to achieve energy redistribution. A bidirectional equalization topology consisting of a forward transformer and switch matrix is proposed first. Then, an innovative equalization strategy based on clustering analysis and genetic algorithm (GA) is developed. Clustering analysis is introduced to identify the target cells to be balanced. To further increase the speed of the equalization process, GA is employed to optimize the classification results. Finally, a series of experiments were conducted to confirm the effectiveness of the proposed topology and the strategy. Both the simulation and experimental results validate that the proposed equalization strategy not only improves the inconsistency but also increases the equalization speed. In practical battery pack experiments, the pack capacity is improved by 16.84% after equalization, and the equalization time is decreased by 23.8% using the proposed method.
The recently observed IceCube PeV events could be due to heavy dark matter (DM) decay. In this paper, we propose a simple DM model with extra U(1)X gauge symmetry and bridge it with standard model ...particles through heavy right-handed neutrino. The Dirac fermion DM χ with mass ∼5 PeV can dominantly decay into a dark Higgs (ϕ), the SM Higgs (h) and a neutrino (ν). If the lifetime of χ is ∼O(1028) s, the resulting neutrino flux can fit data consistently. The neutrino flux from χ→ϕhν in our model is softer than the one predicted from χ→νh, for example. We also discuss a possible mechanism to produce DM with the right relic abundance.
A
bstract
With the latest LHC available results, we consider the generic constraints on massive graviton. Both dijet and dilepton resonance searches are used. The limits on parameter space can be ...applied to many models. As an illustration, we show the constraints for Randall-Sundrum (RS) model. Implications on massive graviton and the coupling strength are discussed. For
k/M
pl
= 0
.
1,
M
G
<
2
.
2 TeV region is excluded at 95% confidence level. We also present some interesting implications on the RS radion with respect to the 125 GeV excess at the LHC. For
k/M
pl
= 0
.
1,
TeV is excluded where
is the scale to charactarize the interaction strengh of radion.
From the facts that numerous regions with initially similar economic conditions end up with different levels of entrepreneurial agglomeration, this paper constructs a model assuming that the ...sequential entrants make their career choices based on existing entrepreneurial ratio and describing the dynamics of entrepreneurial agglomeration formation. After mathematical analysis and numerical simulation using NetLogo, it is found that under social selection, a nonlinear Polya process with self-reinforcing and path-dependency characters will emerge, and the repeated entrants’ career choices will lead to the agglomeration of entrepreneurship; the agent’s risk compensation value, the initial population of agents, the number of role models in the early stage and the initial entrepreneurial ratio are determinants to the formation of entrepreneurial agglomeration. The findings confirm that entrepreneurship has “memory” and the entrepreneurial history could have influence on the future. In order to forge the entrepreneurial agglomeration, our suggestions include exerting influence on the determinants from an early age, and improving the individual’s risk-taking abilities.
The ca. 300 Ma Fengcheng Formation in the Junggar Basin of NW China is reported to develop a rare alkaline lake (soda lake) in this study, based on an expanded literature survey and new insights from ...geological and geochemical data. The development of this ancient alkaline lake resulted from a convergence of favorable paleotectonic, paleogeographic, and paleoclimatic conditions. A detailed characterization of the alkaline lake includes evidence for a pH of >9.0 indicated by δ15N data (average 18.4‰); the presence of alkali minerals such as trona and shortite; globular bacteria-like fossils; low contents of clay minerals; organic and inorganic geochemistry indicating high salinity, strongly reducing conditions, and hydrothermal activity; and a complete sedimentary evolution sequence of an archetypal alkaline lake.
The studied lake deposit is presented as the first such deposit worldwide to generate a large oil reserve, thus allowing scientific insights to be gained into the controls on hydrocarbon generation in alkaline lakes. The alkaline lacustrine source rocks have high contents of organic matter, favorable organic matter type, abundant oil and poor natural gas, multiple phases of hydrocarbon generation, and high hydrocarbon volumes.
The genesis and development of this alkaline lake were controlled jointly by evaporation and volcanic–hydrothermal activity. However, some aspects of this type of lake remain unclear, and future work should explore the integrated evolution of biological–climatic–petroleum-geology systems with respect to alkaline lakes and their associated deposits, and their coupling research with worldwide event then, namely, Glacial episode III of the Late Paleozoic Gondwanan glaciation. Our data suggest that the Fengcheng Formation is a well-preserved archive of Late Paleozoic Ice Age (LPIA) geology and geochemistry around 300 Ma.
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