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Studies on Heavy Metals Levels in Hepatic Tissues of Cat Fishes(Clarias gariepinus)from River Ibi,Donga and Gindin-Dorowa in Taraba State Nigeria,in Relation to key Enzyme of heme Biosynthetic Pathway

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Toxicology Advances 2023年第4期5卷 8-14页

作者： Ebenezer Morayo Ale steve osagie asuelimen Department of Biochemistry Faculty of Pure and Applied SciencesFederal University PMB 1020 WukariWukari 670101Nigeria

Fishes are excellent markers of the extent of pollution from heavy metals in aquatic environments given that they are found at various levels of the food *** study aimed to investigate the bioaccumulation of heavy metals(Zn,Pb,Cd,As,and Hg)as well as the activity of delta-aminolevulinic acid dehydratase(δ-ALA-D)in the livers of cat fishes(Clarias gariepinus)collected from three rivers(Donga,Ibi and Gindin-Dorowa)in Taraba State,*** concentrations of heavy metals in the liver tissues were determined using an atomic absorption spectrophotometer in accordance with the method of AOAC(2019),while theδ-ALA-D activity was assayed using the method of Sassa(1982).Results revealed that only Zn and As were present in the liver samples from the three *** was found only in the liver from Gindin-Dorowa at the concentration of 0.0012mg/kg which is not significant(P<0.05)when compared with other locations,while Hg and Cd were absent in all the liver *** liver sample from Gindin-Dorowa had the highest concentration of Zn(4.2500 mg/kg),followed by Ibi(3.2067 mg/kg),and Donga having the least(2.5500 mg/kg),which were all substantially(P<0.05)different from one ***,there was no significant(P<0.05)difference in the As composition of liver from Donga(0.0013 mg/kg),Ibi(0.0012 mg/kg)and Gindin-Dorowa(0.0010 mg/kg).The result ofδ-ALA-D activity showed that the highest enzymatic activity was found in the liver sample from Donga which has the least Zn and no Pb content,followed by Ibi *** validates the report that heavy metals impairδ-ALA-D ***,the concentrations of all metals in fish livers from all regions do not exceed the acceptable limits set by international law,making them safe for human consumption and possibly not having a negative impact on public *** there is little or no industrial activity in the studied locations,these levels may be consequent to low anthropogenic *** current situation should be sa

关键词： heavy metals bioaccumulation delta-aminolevulinic acid dehydratase Atomic Absorption Spectrophotometer Clarias gariepinus bioaccumulation

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Glutathione peroxidase mimicry of diphenyl diselenide: Plausible contribution of proteins’ thiols

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Toxicology Advances 2023年第2期5卷 14-20页

作者： Ebenezer Morayo Ale steve osagie asuelimen Olawale Otitoju Department of Biochemistry Faculty of Pure and Applied SciencesFederal University WukariTaraba State 670101Nigeria

Organoseleniums are a class of compounds attracting attention across the globe owing to their Glutathione peroxidase(GPx)mimicry,which confers on them a strong antioxidant *** diselenide(DPDS)is an Organoselenium whose GPx mimetic property has been suggested to rely on the oxidation of non-protein or protein thiols critical to the activities of some sulfhydryl *** study,therefore investigated the GPx mimic/antioxidant property of DPDS as well as the role of thiols of two key sulfhydryl enzymes,cerebral Na^(+)/K^(+)-ATPase(sodium pump)and hepatic delta-aminolevulinic acid dehydratase(δ-ALAD)in the GPx mimicry of *** Wistar rats were euthanized,and the liver and brain were removed and used to assay for the effect of DPDS on lipid peroxidation induced by two prooxidants[Fe2^(+)(10μM)and H2O2,(1 mM)]as well as the activities of the sulfhydryl *** results revealed that DPDS profoundly(P<0.05)counteracted Fe2^(+)and H2O2-induced lipid peroxidation in the rats’hepatic and cerebral ***,the results of assay systems for lipid peroxidation and sodium pump revealed that DPDS inhibited Na^(+)/K^(+)-ATPase and lipid peroxidation in the brain tissue homogenates in the same reaction system.A similar result was obtained in the assay system for lipid peroxidation and hepaticδ-ALAD as DPDS simultaneously inhibited the enzyme’s activity and lipid *** suggests that the GPx mimetic property of DPDS may be linked to the enzymes’loss of activity,which further validates the suggestions that the enzymes’inhibition,as well as the antioxidant action of DPDS,rely on the oxidation of critical thiols of the ***,the GPx mimicry of DPDS should be investigated in the presence of thiol-blocking or oxidizing agents in biological systems in order to further ascertain the role of protein thiols.

关键词： Organoseleniums diphenyl diselenide Glutathione peroxidase antioxidant thiols delta-aminolevulinic acid dehydratase Na^(+)/K^(+)-ATPase

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Ethanolic extract of Abrus precatorius leaves protected against mercury chloride-induced hepatocellular damage and cerebral Na+/K+-ATPase dysfunction in wistar rats

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Toxicology Advances 2023年第2期5卷 8-13页

作者： Ebenezer Morayo Ale steve osagie asuelimen Isaac John Umaru Bunmi Olaoluwa Olorundare Victoria Ifeoluwa Ayo Mgbede Joy Timothy Philip Shadrach Department of Biochemistry Faculty of Pure and Applied SciencesFederal University WukariTaraba State 670101Nigeria Department of Cocoa Research Institute of Nigeria IbadanOyo State 200261Nigeria

Plants are sources of medicinal compounds,and they play a crucial role in human health *** precatorius is one of the important medicinal plants that have been alleged for their medicinal *** research unraveled the pharmacological effect of ethanolic extract of Abrus precatorius on lipid peroxidation,liver parameters,and Na^(+)/K^(+)-ATPase activity in HgCl_(2) treated wistar ***-four(24)albino wistar rats weighing between 150-200 g were distributed into four groups of 6 animals *** A(control)received normal saline(0.9% NaCl),group B received 400 mg/kg of the extract only,group C received 4 mg/kg HgCl_(2) only,and group D received 400 mg/kg of extract+4 mg/kg of HgCl_(2).The treatment lasted for two weeks,and the animals were sacrificed on the 15th *** blood,brains and livers were collected and used for assay of lipid peroxidation,liver function,and sodium pump *** results of liver function test revealed an elevated(P<0.05)level of serum aspartate transaminase,alanine transaminase,alkaline phosphatase,and total bilirubin in the group that received HgCl_(2) only(group C)when compared with the normal control(group A)that received normal saline ***,the administration of extract in group D led to a marked(P<0.05)reduction in the activities of these enzymes and the level of total bilirubin when compared to the negative control(group C).On the contrary,HgCl_(2) caused a significant(P<0.05)reduction in serum total protein and albumin levels,but the extract reversed the effect of HgCl_(2) by elevating their ***,the effect elicited by this extract is comparable to group A which received normal ***,the result of lipid peroxidation revealed that HgCl_(2) treatment caused a marked(P<0.05)increase in the formation of lipid peroxidation adducts in both liver and brain homogenates in group *** the contrary,administration of Abrus precatorius extract profoundly(P<0.05)inhibited HgCl_(2)-

关键词： ethanolic extract Abrus precatorius hepatic parameters lipid peroxidation Na^(+)/K^(+)-ATPase activity mercury chloride in vivo

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Investigation of heavy metals and lipid peroxidation level in the muscles of Clarias gariepinus from IBI,Gindin-Dorowa and D onga community rivers in Taraba State,Nigeria

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Toxicology Advances 2023年第3期5卷 33-37页

作者： asuelimen steve osagie Ale Ebenezer Morayo Department of Biochemistry Faculty of Pure and Applied SciencesFederal University PMB 1020 Wukari200 Katsina-Ala RoadWukari 670101Nigeria

Heavy metals have harmful effects on human health,and exposure to these metals has been increased by industrial and anthropogenic activities and modern *** metals content of the liver tissues was determine d using Atomic Absorption Spectrophotometer method,while lipid peroxidation was carried *** metals analyzed include;lead(Pb),cadmium(Cd),zinc(Zn),Arsenic(As),and Mercury(Hg).The findings revealed that the heavy metal Zinc(Zn)has high concentrations in the muscles of the fish species,the concentration of this heavy metal Zinc is high in River Gindin Dorowa th a n in River Ibi and River Donga shows less concentration of this heavy metal though it’s above WHO permissible *** revealed that only Zn and Cd were present in the muscle from the three *** was found only in the liver from Gindin-Dorowa at the concentration of 0.017 mg/kg,which is not significant(P<0.05)when compared with other locations,while Hg and As were absent in all the muscle *** highest concentration of Zn was found in the muscle sample from Gindin-Dorowa(7.450 mg/kg)followed by Ibi(6.16 mg/kg)and the least being Donga(4.365 mg/kg)which are significantly(P<0.05)different from one ***,there was no significant(P<0.05)difference among the Cd composition of muscle from Gindin-Dorowa(0.025 mg/kg),Donga(0.024 mg/kg)and Ibi(0.015 mg/kg),*** TBA was found in the hepatic tissue sample from Gidin-Dorowa,which has the highest Zn,Cd and no Pb content,followed by Ibi and then the Donga *** suggests that there is a positive relationship between heavy metals and the effect of TBA on the hepatic tissues,justifying the fact that heavy metals affect the hepatic tissues of fish,while on the cerebral *** conclusion,it revealed that there is a negative relation between heavy metals and the effect of TBA on the cerebral tissues to protect or save aquatic habitat s of fish quality and aquatic life.

关键词： heavy metals lipid peroxidation Clarias gariepinus bioaccummulation

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Digital neuromorphic technology: current and future prospects

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National Science Review 2024年第5期11卷 10-11页

作者： steve Furber Department of Computer Science The University of Manchester

Neuromorphic technology has diversified considerably from its origins in the seminal work by Carver Mead and his group at Caltech in the 1980s [1]. That early work focussed on the analogy between the equations describing the flow of ions in biological neurons and the equations describing the flow of carriers in field-effect transistors operating in the subthreshold region.

关键词： technology current future digital neuromorphic prospects

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Modern Black Sea oceanography applied to the end-Permian extinction event

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Journal of Palaeogeography 2015年第1期4卷 52-62页

作者： steve Kershaw Institute for the Environment Health and Societies Brunel UniversityKingston LaneUxbridge Middlesex UB8 3PH UK

The modern Black Sea has a mixed upper layer in the top 150-200 m of the water column, below which the water is anoxic, separated from the mixed layer by a redox boundary. There is limited vertical movement of water. Pyrite framboids form in the water column of the anoxic zone, then have been traditionally interpreted to sink immediately and accumulate in the sediments of the Black Sea. Thus the occurrence of framboids in sediments in the rock record is widely interpreted to indicate poorly oxygenated to anoxic conditions in ancient environments. However, in the Permian-Triassic boundary （PTB） microbialites of South China, which formed in shallow marine conditions in contact with the atmosphere, the published occurrence of framboids is inconsistent with abundant gastropod and ostracod shells in the microbialite. Furthermore, in the modern Black Sea, （a） framboids may be suspended, attached to organic matter in the water column, thus not settle to the sea floor immediately after formation; and （b） the redox zone is an unstable complex area subject to rapid vertical water movement including occasional upwelling. The model presented here supposes that upwelling through the redox zone can lead to upward transport of suspended pyrite framboids into the mixed layer. Advective circulation could then draw suspended framboids onto the shelf to be deposited in oxygenated sediments. In the Permian-Triassic transition, if framboids were upwelled from below the redox boundary and mixed with oxygenated waters, sediment deposited in these conditions could provide a mixed signal for potentially misleading interpretations of low oxygen conditions. However, stratigraphic sampling resolution of post-extinction microbialites is currently insufficient to demonstrate possible separation of framboid-bearing layers from those where framboids are absent. Profound differences between microbialite constructors and sequences between the western and eastern Tethys demonstrate barriers to migra

关键词： mass extinction Permian-Triassic boundary microbialite ostracods gastro-pods anoxia Black Sea

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Improving reflectance estimation by BRDF-consistent region clustering

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Progress in Natural Science:Materials International 2006年第3期16卷 313-320页

作者： LIN steve Beijing 100080 China Visual Computing Group Microsoft Research Asia

Previous studies in reflectance estimation generally require prior segmentation of an image into regions of uniform reflectance. Due to the measurement noise and limited sampling of the BRDF (bi-directional reflectance function) directions, such estimated results of reflectance are not accurate. In this paper, we propose a novel method for reducing uncertainty in reflectance estimates by merging image regions which have consistent reflectance observations. Each image region acts as a reflectance subspace, so merging of the image regions can result in subspace reduction. We propose a Bayesian segmentation framework to decrease the reflectance uncertainty by using novel merging criteria. Finally, a maximum likelihood reflectance estimation is made for each resulting image region. Experimental results verify the feasibility and superiority of this reflectance-oriented region merging method.

关键词： texture shading grouping and segmentation reflectance estimation BRDF uncertainty.

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Quantitative Absolute Continuity of Harmonic Measure and the Dirichlet Problem: A Survey of Recent Progress

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Acta Mathematica Sinica,English Series 2019年第6期35卷 1011-1026页

作者： steve HOFMANN Department of Mathematics University of Missouri

It is a well-known folklore result that quantitative, scale invariant absolute continuity(more precisely, the weak-A∞ property) of harmonic measure with respect to surface measure, on the boundary of an open set Ω ? R^(n+1) with Ahlfors–David regular boundary, is equivalent to the solvability of the Dirichlet problem in Ω, with data in L^p (?Ω) for some p < ∞. Drawing an analogy to the famous Wiener criterion, which characterizes the domains in which the classical Dirichlet problem, with continuous boundary data, can be solved, one may seek to characterize the open sets for which L^psolvability holds, thus allowing for singular boundary *** has been known for some time that absolute continuity of harmonic measure is closely tied to rectifiability properties of ?Ω, but also that rectifiability alone is not sufficient to guarantee absolute continuity. In this note, we survey recent progress in this area, culminating in a geometric characterization of the weak-A∞ property, and hence of solvability of the L^p Dirichlet problem for some finite p. This characterization, obtained under rather optimal background hypotheses, follows from a combination of the present author's joint work with Martell, and the work of Azzam, Mourgoglou and Tolsa.

关键词： Harmonic measure Poisson kernel uniform rectifiability weak local John condition big pieces of chord-arc domains Carleson measures

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Underground mine stream crossing assessment:A multi-disciplinary approach

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International Journal of Mining Science and Technology 2021年第1期31卷 59-65页

作者： Kevin Andrews steve Keim Marshall Miller&Associates BluefieldVA 24605USA

Underground mine designs typically try to avoid extraction beneath streams and rivers of any significant size,especially when the overburden rock thickness between the stream bed and the mine is *** issues with mining beneath streams include excessive groundwater inflow to the mine,weak ground(roof,floor,and pillar)conditions,horizontal stress effects,as well as stream loss and other potential adverse environmental ***,there are times when crossing beneath a stream or river is necessary to move into a new area of mineral reserve without creating additional mine access points from the ground ***,stream crossings are completed without thorough assessment,potentially resulting in increased costs,decreased safety,and,in some cases,failure to advance the *** of the most favorable location(s)to cross the stream must account for numerous factors and the associated assessment often requires a multi-disciplinary *** crossing investigations often require geological,hydrogeological,geotechnical,and geophysical *** of stream crossing investigations include desktop evaluation of maps and aerial photography,stream bed observations,drilling,detailed rock core logging,downhole geophysical surveying,hydraulic conductivity testing(packer testing),geotechnical laboratory testing,assessment,and *** deliverables from a stream crossing assessment typically include geological,geotechnical,and hydrogeological characterization of potential stream crossing locations,classification of favorable and unfavorable crossing locations,recommendations for entry design and pillar sizing,and recommendations for if,and how,to conduct pre-grouting *** of technical aspects of data collection and assessment are provided based on decades of industry experience conducting stream crossing assessments in various underground mining scenarios.

关键词： Underground mining Geotechnical Stream-crossing Hydrogeology Characterization

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Green spermatozoa illuminate a 30-year-old model： sperm-egg adhesion involves intra-acrosomal proteins

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Asian Journal of Andrology 2011年第5期13卷 665-666页

作者： steve Tardif Reproductive and Developmental Biology Group Centrefor Oncology and Molecular Medicine Division ofMedical Sciences Ninewells Hospital University ofDundee Dundee Scotland DD1 9SY UK

Fertilisation in mammals involves many synchronized steps including spermegg adhesion. Prior to sperm-oolemma fusion, spermatozoa need to undergo the acrosome reaction （AR） or exocytosis. The universal belief, for many years, has been that the AR was initiated upon binding to the zona pellucida （ZP）. As such acrosomal proteins were not thought to be involved in the primary contact with the ZP. These proteins were only suggested to be biologically relevant once the sperm were attached to the ZP and during subsequent events. However,

关键词： Cardiovascular diseases Clinical trials Drug discovery and development

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