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Effects of heavy metals (Pb^(2+) and Cd^(2+)) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium synechocystis sp. PCC 6803

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Chinese Journal of Oceanology and limnology 2009年第2期27卷 383-388页

作者： k. k. I. U. Arunakumara 张学成 College of Marine life sciences Ocean University of China Department of Crop science Faculty of AgricultureUniversity of Ruhuna

The unicellular cyanobacterium synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb^2＋ and Cd〉（0, 0.5, 1, 2, 4, 6 and 8 mg/l）. The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the synechocystis sp. PCC 6803 cells became evident with the increased （〉4 mg/l Pb^2＋） metal concentration. The photosynthetic apparatus （thylakoid membranes） were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration （8 mg/l pb^2＋）, the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations （0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/l pb^2＋）, both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents （chlorophyll a, 13 carotene and phycocyanin） were also decreased with increasing metal concentration. Cells exposed to 6 mg/l Pb^2＋, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, 13 carotene and phycocyanin respectively over the control. Corresponding reductions for the same CdZ＋concentrations were 57.83, 48.94 and 56.90%. lethal concentration （96 h lC50） values （3.47 mg/l Cd^2＋ and 12.11 mg/l Pb^2＋） indicated that synechocystis sp. PCC 6803 is more vulnerable to Cd^2＋ than Pb^2＋.

关键词： growth pigment contents synechocystis sp. PCC 6803 ultrastructure

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looking ahead to significant improvements in mining safety and health through innovative research and effective diffusion into the industry

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International Journal of Mining science and Technology 2015年第3期25卷 325-332页

作者： Jeffery l.kohler The Pennsylvania state University

Mining safety and health improvements over the past decades are remarkable by many metrics, and yet the expectation of society, and the goal of the mining industry, is zero harm. If we examine the underlying enablers for the significant gains that have been achieved, the key role that research to help understand the causes of problems and to develop lasting solutions is clear. Many of the remaining challenges have been resistant to solutions by various approaches. some, such as fatalities and injuries from ground control or powered haulage are prominent year after year. Different approaches are indicated and new solutions will be required if we are to achieve a goal of zero harm. These will originate with research, but into which topics, and what are some of these different approaches? This paper examines the current state of mine safety in the United states and highlights areas of significant opportunity for research that will lead to solutions. The likely direction of research that will enable realization of the ‘‘zero harm'' goal is described in terms of evolutionary and revolutionary approaches. Both are important, but the author's view is that some of the largest gains will be made with trans-disciplinary approaches that break from the past. Topical areas of research are suggested and several research questions are given to illustrate the direction of future research in mining safety and health.

关键词： Mining safety Mining health Mining research Health and safety management systems

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Betti Numbers of locally standard 2-Torus Manifolds

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Chinese Annals of Mathematics,series B 2014年第4期35卷 599-606页

作者： Junda CHEN Zhi lü school of Mathematical sciences Fudan University school of Mathematical sciences and the key laboratory of Mathematics for Nonlinear sciences of Ministry of Education Fudan University

let Mn be a smooth closed n-manifold with a locally standard （Z2）n-action. This paper deals with the relationship among the rood 2 Betti numbers of Mn, the mod 2 Betti numbers and the h-vector of the orbit space of ... 详细信息

关键词： locally standard 2-torus action Manifold with corners Betti number

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Recent progress in superhydrophobic and superamphiphobic coatings for magnesium and its alloys

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Journal of Magnesium and Alloys 2021年第3期9卷 748-778页

作者： Viswanathan s.saji Center of Research Excellence in Corrosion King Fahd University of Petroleum&Minerals(KFUPM)Dhahran 31261Saudi Arabia

superhydrophobic coatings are projected as a practical approach to tackle the weak aqueous corrosion resistance of Mg/Mg *** present review provides the most recent updates in this *** various low surface energy treatments reported are presented first,followed by the methods employed for developing hierarchical surface micro/*** works in different application areas,including anti-corrosion,biomedical and anti-icing are systematically *** descriptions of self-healing characteristics and long-term durability of the superhydrophobic surfaces *** on superamphiphobic surfaces also deliberated.

关键词： Magnesium Mg alloys superhydrophobic superamphiphobic Coatings self-healing Corrosion

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smoothness of the Gradient of Weak solutions of Degenerate linear Equations

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Acta Mathematica sinica,English series 2018年第1期34卷 42-62页

作者： Richard l.WHEEDEN Department of Mathematics Rutgers University

let Q（x） be a nonnegative definite, symmetric matrix such that √Q（X） is lipschitz con- tinuous. Given a real-valued function b（x） and a weak solution u（x） of div（QVu） = b, we find sufficient conditions in order that √Qu has some first order smoothness. specifically, if is a bounded open set in Rn, we study when the components of vVu belong to the first order sobolev space W1＇2（Ω） defined by sawyer and Wheeden. Alternately we study when each of n first order lipschitz vector field derivatives Xiu has some first order smoothness if u is a weak solution in Ω of ^-^-1 X^Xiu ＋ b = O. We do not assume that {Xi}is a Hsrmander collection of vector fields in ~. The results signal ones for more general equations.

关键词： Degenerate elliptic differential equations degenerate quadratic forms weak solutions,second order regularity

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Crystal structure of acetylcholinesterase catalytic subunits of the malaria vector Anopheles gambiae

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Insect science 2018年第4期25卷 721-724页

作者： Qian Han Dawn M. Wong Howard Robinson Haizhen Ding Polo C. H. lam Maxim M. Totrov Paul R. Carlier Jianyong li laboratory of Tropical Veterinary Medicine and Vector Biology and Hainan Key Laboratory of Sustainable Utilization of Tropical Bioresources College of Agriculture Hainan University Haikou China Department of Biochemistry Virginia Tech Blacksburg Virginia USA Department of Chemistry Virginia Tech Blacksburg Virginia USA Biology Department Brookhaven National Laboratory Upton New York USA Molsoft llC San Diego California USA

Dear Editor, Acetylcholinesterase （ACHE） hydrolyzes the neurotransmitter acetylcholine at cholinergic synapses in the central nervous system （Toutant, 1989）. Inhibition of the enzyme in insects could lead to the d... 详细信息

关键词： ACETYlCHOlINEsTERAsE ANOPHElEs gambiae CRYsTAl structure

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The non-uniformity study under geo-magnetic field of 20-inch MCP-PMT for lHAAsO

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Radiation Detection Technology and Methods 2024年第3期8卷 1377-1389页

作者： C.C.liu B.Gao s.X.lu M.J.Chen X.H.You k.li lin liu W.k.Gao Zhengzhou University Zhengzhou450001China Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China TIANFU Cosmic Ray Research Centre 1500 Ke Zhi RoadChengduChina University of Chinese Academy of sciences Beijing100043China

Purpose The large diameter photon sensors are widely applied in astroparticle physics and neutrino physics *** to its large size,the geo-magnetic effect cannot be *** this work,one 20-inch MCP-PMT are scanned under geo-magnetic field and magnetic shielding environment,and finally,the multi-parameter scanning results are *** In order to evaluate the response of MCP-PMTs,an automatic spherical scanning system based on stepper motor and quartz fiber was established.A comprehensive multi-point scanning was performed on the entire 20-inch MCP-PMT,and a multi parameter data scanning model was *** self-developed magnetic shielding was used to demonstrate the improvement of magnetic shielding on the ratio of signals,charge uniformity,and time characteristics of the 20-inch *** By comparing the results with and without magnetic shielding,it can be concluded that with magnetic shielding,the variation in charge spectrum and the ratio of signals are relatively *** the same time,the composition of photon time spectrum has become *** relative transit time and time spread of photons are reduced to a certain extent,and the uniformity of both is also *** The use of magnetic shielding has improved the various performance of MCP-PMT,preparing for future lHAAsO and other experiments.

关键词： Photon-sensor Geo-magnetic effect Non-uniformity

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A movable beast: glaciation in the Ediacaran

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National science Review 2023年第8期10卷 119-120页

作者： Joseph l. kirschvink The Marine Core Research Institute Kochi University Division of Geological&Planetary sciences California Institute of Technology

Ediacaran time(635–543 million years ago [Ma]) represents the dawn of macroscopic life following two Neoproterozoic snowball Earth episodes [1], where a runaway ice-albedo effect caused the entire planet to become en...

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Hippo signaling and epithelial cell plasticity in mammalian liver development, homeostasis, injury and disease

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science China(life sciences) 2019年第12期62卷 1609-1616页

作者： Randy l.Johnson Department of Cancer Biology University of Texas MD Anderson Cancer Center

A traditional view of cellular differentiation is unidirectional: progenitor cells adopt specific fates in response to environmental cues resulting in deployment of cell-specific gene expression programs and acquisition of unique differentiated cellular properties such as production of structural and functional proteins that define individual cell types. In both development and in tissue repair stem and progenitor cells are thought to both self-renew to maintain the pool of precursors and to expand to give rise to transient amplifying and differentiated cell types. Recently, however, it has become appreciated that differentiated cell types can be reprogrammed to adopt progenitor and stem cell properties. In the case of epithelial cells in the mammalian liver, hepatocytes and biliary epithelial cells there is a significant degree of plasticity between these lineages that has been implicated in mechanisms of tissue repair and in liver pathologies such as cancer. Recent studies have highlighted the role of Hippo signaling, an emerging growth control and tumor suppressor pathway, in regulating epithelial cell plasticity in the mammalian liver and in this review, the role of cellular plasticity and Hippo signaling in regulating normal and abnormal tissue responses in the mammalian liver will be discussed.

关键词： liver homeostasis plasticity regeneration cancer Hippo pathway

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From common gardens to candidate genes:an elegant case of homoploid hybrid speciation

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Molecular Plant 2021年第2期14卷 200-201页

作者： Gregory l.Owens Department of Biology University of VictoriaVictoriaBCCanada

Homoploid hybrid speciation(HHs),where genetic contributions from two species combine to produce a third species without a change in pioidy,remains an intriguing and enigmatic evolutionary *** studies in the past decade have shown that introgression and admixture between species is common,and yet well documented cases of HHs remain rare(schumer et al.,2014;Marques et al.,2019).This strikes at a key feature of HHs;it is a far higher bar to prove that hybridization was critical for speciation than it is to show that introgression *** former requires us to know how reproductive isolation(RI)is achieved,identify hybrid ancestry,and definitively link hybrid ancestry with reproductive *** this in mind,the work by Wang et al.(2020)fully documenting a case of HHs is particularly impressive in terms of both the scope and clarity of the results.

关键词： al. combine intro

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