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Journal of Earth Science 2024年第1期35卷 16-28页

作者： Landry Soh Tamehe Huan Li Sylvestre Ganno Zuxing Chen Yanick Brice Lemdjou Safiyanu Muhammad Elatikpo School of Geosciences and Info-Physics Central South UniversityChangsha 410083China department of Earth Sciences University of Yaounde IYaounde 3412Cameroon Institute of Oceanology Chinese Academy of SciencesQingdao 266071China department of Geology Ahmadu Bello University ZariaZaria 810107Nigeria

The Bipindi iron ore district is located in the central section of the Nyong Complex at the northwestern margin of the Congo Craton in Southwest Cameroon.This iron district contains numerous iron mineralization hosted by the Mewongo,Bibole,Kouambo,and Zambi banded iron formations(BIFs).These BIFs contain magnetite as the main iron ore mineral associated with pyrite,and gangue minerals are quartz with minor chlorite and amphibole.The origin of iron ore from these BIFs was investigated using a combination of in-situ magnetite and whole-rock chemistry.The studied BIF ore samples have a narrow range of TFe between 30.90 wt.%and 43.20 wt.%,indicating a low-grade ore.The geochemical signatures of magnetite such as low contents of base metals(e.g.,Cu,Co,V,and Zn)and low Co/Zn ratios600 and>75,respectively),we suggest that magnetite was derived from a mixture of seawater and~0.1%low-temperature hydrothermal fluids in an oxidizing environment.Collectively,low-temperature hydrothermal and later metamorphic fluids were necessary for the transformation of the protolith Nyong Complex BIFs to iron ore.

关键词： banded iron formations iron ore geochemistry Congo Craton trace element composition LA-ICP-MS

Phytoremediation Strategies for Heavy Metal Contamination: A Review on Sustainable Approach for Environmental Restoration

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Journal of Environmental Protection 2024年第4期15卷 450-474页

作者： Mariam Salifu Matthew Abu John Murtala Abubakar Ibukunoluwa Abimbola Bankole Nneka Damola Ajayi Olawumi Amusan department of Chemistry and Biochemistry University of Mississippi Olemiss MS USA department of Biochemistry Ahmadu Bello University Zaria Nigeria department of Plant Pathology North Dakota State University Fargo ND USA Directorate of Research and Development Nigerian Institute of Leather and Science Technology (NILEST) Zaria Nigeria department of Chemistry University of Akron Akron OH USA

Current globalization trends and important breakthroughs globally need a complete study of heavy metal contamination, its causes, its impacts on human and environmental health, and different remediation strategies. Heavy metal pollution is mostly produced by urbanization and industry, which threatens ecosystems and human health. Herein, we discuss a sustainable environmental restoration strategy employing phytoremediation for heavy metal pollution, the carcinogenic, mutagenic, and cytotoxic effects of heavy metals such as cadmium, copper, mercury, selenium, zinc, arsenic, chromium, lead, nickel, and silver, which may be fatal. Phytoremediation, which was prioritized, uses plants to remove, accumulate, and depollute pollutants. This eco-friendly method may safely collect, accumulate, and detoxify toxins using plants, making it popular. This study covers phytostabilization, phytodegradation, rhizodegradation, phytoextraction, phytovolatilization, and rhizofiltration. A phytoremediation process’s efficiency in varied environmental circumstances depends on these components’ complex interplay. This paper also introduces developing phytoremediation approaches including microbe-assisted, chemical-assisted, and organic or bio-char use. These advancements attempt to overcome conventional phytoremediation’s limitations, such as limited suitable plant species, location problems, and sluggish remediation. Current research includes machine learning techniques and computer modeling, biostimulation, genetic engineering, bioaugmentation, and hybrid remediation. These front-line solutions show that phytoremediation research is developing towards transdisciplinary efficiency enhancement. We acknowledge phytoremediation’s promise but also its drawbacks, such as site-specific variables, biomass buildup, and sluggish remediation, as well as ongoing research to address them. In conclusion, heavy metal pollution threatens the ecology and public health and must be reduced. Phytoremediation treats heavy metal pollution in different ways.

关键词： Phytoremediation Heavy-Metal Contamination Sustainability Restoration

Transient Dean flow in a composite annular duct with porous walls partially filled with porous material

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Propulsion and Power Research 2022年第1期11卷 118-128页

作者： Basant K.Jha Taiwo S.Yusuf department of mathematics Ahmadu Bello UniversityZariaNigeria

This work presents a semi-analytical solution of transient Dean flow in a composite annular duct with porous walls partially filled with porous materials.The flow is set up as a result of the imposed pressure gradient in the azimuthal eqT direction while both the outer and the inner cylinders are fixed.The appropriate governing equations for the flow are rendered dimensionless and transformed using suitable techniques,the Laplace transform technique is further used to transform the partial differential equations into the total differential equation.The solution of the ODE is later transformed to the time domain using the well-known Riemann-sum approximation approach.To validate the accuracy of the numerical scheme deployed in this research,numerical comparison of the steady-state solution,and the values generated using the implicit finite difference on the transient state model is presented.Generally,higher dominance of clear fluid and fluid injection at the inner cylinder is found to enhance the fluid velocity at the fluid interface.It is also good to note that injection of fluid at the inner cylinder pose a decreasing influence on the flow with minimum or no effect near the point R=1.7.

关键词： Circumferential flow Darcy number Composite annulus Taylor Porous walls Azumuthal

On Fractional Differential Inclusion for an EpidemicModel via L-Fuzzy Fixed Point Results

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Computer Modeling in Engineering & Sciences 2023年第11期137卷 1937-1956页

作者： Maha Noorwali Mohammed Shehu Shagari department of mathematics King Abdulaziz UniversityJeddahSaudi Arabia department of mathematics Faculty of Physical SciencesAhmadu Bello UniversityZariaNigeria

The real world is filled with uncertainty,vagueness,and imprecision.The concepts we meet in everyday life are vague rather than precise.In real-world situations,if a model requires that conclusions drawn from it have some bearings on reality,then two major problems immediately arise,viz.real situations are not usually crisp and deterministic;complete descriptions of real systems often require more comprehensive data than human beings could recognize simultaneously,process and understand.Conventional mathematical tools which require all inferences to be exact,are not always efficient to handle imprecisions in a wide variety of practical situations.Following the latter development,a lot of attention has been paid to examining novel L-fuzzy analogues of conventional functional equations and their various applications.In this paper,new coincidence point results for single-valued mappings and an L-fuzzy set-valued map in metric spaces are proposed.Regarding novelty and generality,the obtained invariant point notions are compared with some well-known related concepts via non-trivial examples.It is observed that our principal results subsume and refine some important ones in the corresponding domains.As an application,one of our results is utilized to discussmore general existence conditions for realizing the solutions of a non-integer order inclusion model for COVID-19.

关键词： Hausdorff metric L-fuzzy set L-fuzzy set-valued map Caputo fractional differential inclusion COVID-19

Natural convection flow in a vertical annulus with time-periodic thermal boundary conditions

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Propulsion and Power Research 2019年第1期8卷 47-55页

作者： Basant K.Jha Michael O.Oni department of mathematics.ahmadu bello university Zaria.Nigeria

This paper presents an analytical solution for natural convection flow in a vertical annulus due to time-periodic heating of annulus surfaces.Closed-form expressions for velocity,temperature,skin-friction,mass flow rate and rate of heat transfer which is expressed as Nusselt number are obtained by solving the present mathematical model after separating into steady component and periodic regime.The effects of pertinent parameters such as Strouhal number(St),Prandtl number(Pr)and radius ratio(λ)are shown with the aid of contour and line graphs.Results indicate that the role of Strouhal number and Prandtl number is to decrease fluid velocity,temperature and skin-friction.Furthermore,increase in Strouhal number increases the temperature phase-lag.

关键词： Natural convection Fully developed flow Time-periodic heating Vertical annulus Strouhal number

Physical activity and amyloid beta in middle-aged and older adults:A systematic review and meta-analysis

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Journal of Sport and Health Science 2024年第2期13卷 133-144页

作者： María Rodriguez-Ayllon Patricio Solis-Urra Cristina Arroyo-ávila Miriam álvarez-Ortega Pablo Molina-García Cristina Molina-Hidalgo Manuel Gómez-Río Belinda Brown Kirk I.Erickson Irene Esteban-Cornejo department of Epidemiology Erasmus University Medical Center RotterdamRotterdamGD 3015the Netherlands department of Physical Education and Sports Faculty of Sport SciencesSport and Health University Research Institute(iMUDS)University of GranadaGranada 18071Spain Faculty of Education and Social Sciences Universidad Andres BelloVina del Mar 2531015Chile department of Nuclear Medicine Virgen de las Nieves University HospitalInstitute of Biosanitary Research of Granada(IBS)Granada 18014Spain Physical Medicine and Rehabilitation Service Virgen de las Nieves University HospitalInstitute of Biosanitary Research of Granada(IBS)Granada 18014Spain department of Psychology University of PittsburghPittsburghPA 15260USA Centre for Healthy Ageing Health Futures InstituteMurdoch UniversityMurdochWA 6150Australia School of Medical and Health Sciences Edith Cowan UniversityJoondalupWA 6027Australia Advent Health Research Institute Neuroscience Institute OrlandoOrlandoFL 32803USA Physiopathology of Obesity and Nutrition Research Center(CIBERobn) Institute of Health Carlos Ⅲ(ISCⅢ)Madrid 28029Spain

Background:One of the pathological hallmarks distinguishing Alzheimer’s disease from other dementias is the accumulation of amyloid beta(Aβ).Higher physical activity is associated with decreased dementia risk,and one potential path could be through Aβlevels modulation.We aimed to explore the relationship between physical activity and Aβin middle-aged and older adults.Methods:A systematic search of PubMed,Web of Science,PsycINFO,Cochrane Central Register of Controlled Trials,and SPORTDiscus was performed from inception to April 28,2022.Studies were eligible if they included physical activity and Aβdata in adults aged 45 years or older.Multi-level metaanalyses of intervention and observational studies were performed to examine the role of physical activity in modulating Aβlevels.Results:In total,37 articles were included(8 randomized controlled trials,3 non-randomized controlled trials,4 prospective longitudinal studies,and 22 cross-sectional studies).The overall effect size of physical activity interventions on changes in blood Aβwas medium(pooled standardized mean difference=-0.69,95%confidence interval(95%CI):-1.41 to 0.03;I^(2)=74.6%).However,these results were not statistically significant,and there were not enough studies to explore the effects of physical activity on cerebrospinal fluid(CSF)and brain Aβ.Data from observational studies were examined based on measurements of Aβin the brain using positron emission tomography scans,CSF,and blood.Higher physical activity was positively associated with Aβonly in the CSF(Estimate r=0.12;95%CI:0.05-0.18;I^(2)=38.00%).Conclusion:Physical activity might moderately reduce blood Aβin middle-aged and older adults.However,results were only near statistical significance and might be interpreted with caution given the methodological limitations observed in some of the included studies.In observational studies,higher levels of physical activity were positively associated with Aβonly in CSF.Therefore,further research is needed to understand the modulating role of physical act

关键词： Aging Cognitive impairment Dementia Exercise PET

Allogenic Stem Cell Transplantation and COVID-19 Antibodies: Mechanistic Insights and Recipient Concerns

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Open Journal of Immunology 2024年第2期14卷 16-32页

作者： Amna Umer Asma Umer Khayam Nasar Khan David Lawrence Greene Umm E. Habiba Sabiha Shamim Pak-American Hospital Pvt. Ltd. Islamabad Pakistan R3 Medical Research LLC Scottsdale USA bello Bio Labs and Therapeutics (SMC) Pvt. Ltd. Islamabad Pakistan department of Biochemistry Rawalpindi Medical University Rawalpindi Pakistan bello Bio LLC Scottsdale USA

Collecting umbilical cord stem cells is widely practiced due to its numerous benefits. Over the past decade, umbilical cord stem cells (UCSCs) have shown effectiveness in treating various conditions, such as bone pathologies, neuropsychiatry disorders, hereditary diseases, and metabolic disorders. However, factors like immunization affect the quantity and quality of cord harvesting. Studies suggest that antibodies from the mother pass through the umbilical cord to protect the infant against infections. Cleaning the umbilical cord before stem cell extraction is crucial to maintain sterility and cell integrity. Vaccinating a female donor, including for COVID-19, typically does not directly affect the stem cells. Although vaccines aim to trigger an immunological response, they generally do not affect the donor’s stem cells.

关键词： Vaccination Stem Cell Allogeneic COVID Antibodies

Time-dependent MHD Couette flow of rotating fluid with Hall and ion-slip currents

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Applied mathematics and Mechanics(English Edition) 2012年第4期33卷 399-410页

作者： B.K.JHA C.A.APERE department of mathematics Ahmadu Bello University

The unsteady magnehydrodynamics （MHD） Couette flow of an electrically conducting fluid in a rotating system is investigated by taking the Hall and ion-slip currents into consideration. The derived fundamental equations on the assumption of a small magnetic Reynolds number are solved analytically with the well-known Laplace transform technique. The unified closed-form expressions axe obtained for the velocity and the skin friction in the two different cases of the magnetic field being fixed to either the fluid or the moving plate. The effects of various parameters on the velocity and the skin friction axe discussed by graphs. The results reveal that the primary and secondary velocities increase with the Hall current. An increase in the ion-slip paxameter also leads to an increase in the primary velocity but a decrease in the secondary velocity. It is also shown that the combined effect of the rotation, Hall, and ion-slip parameters determines the contribution of the secondary motion in the fluid flow.

关键词： magnehydrodynamics （MHD） Couette flow rotating system Hall andion-slip currents accelerated motion

A Comparative study on generalized Manev potential and Newtonian potential in perturbed restricted four-body problem

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Applied mathematics(A Journal of Chinese Universities) 2023年第1期38卷 44-57页

作者： Jagadish Singh Omale Solomon Okpanachi department of mathematics Faculty of Physical SciencesAhmadu Bello UniversityZariaNigeria department of Engineering and Space Systems National Space Research and Development Agency(NASRDA)Obasanjo Space CentreAbujaNigeria

The motion of a test particle within the context of the restricted four-body problem(R4BP)driven by a new kind of potential,called the generalized Manev potential,with perturbations in the Coriolis and centrifugal forces is considered in this study.The system possesses eight libration points which were distributed on its plane of motion in different manner from those of the usual Newtonian potential.Unlike the case of the perturbed R4BP under Newtonian potential,where two of these librations are stable,all of them are unstable in linear sense under Manev potential.We found that a gradual perturbation in the centrifugal force causes the trajectories of motion to drift inward but the Coriolis force was proven to have no effect on the location of the libration points of the system.Using first order Lyapunov characteristic exponents,the dynamical behavior of the system is found irregular.We experimented with a high velocity stellar system(82 G.Eridani)to establish the applicability of the model in astrophysics.

关键词： generalized Manev potential Coriolis force centrifugal force stability chaotic 82 G.Eridani

Driving factors behind multiple populations

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 172-181页

作者： Ruoyun Huang Baitian Tang Chengyuan Li Doug Geisler Mario Mateo Ying-Yi Song Holger Baumgardt Julio A.Carballo-bello Yue Wang Jundan Nie Bruno Dias JoséG.Fernández-Trincado School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area Zhuhai 519082China Departamento de Astronomía Universidad de ConcepcionConcepcionChile Instituto de Investigación Multidisciplinario en Ciencia y Tecnología Universidad de La SerenaLa SerenaChile Departamento de Astronomía Facultad de CienciasUniversidad de La SerenaChile department of Astronomy University of MichiganAnn Arbor 48109USA David A.Dunlap department of Astronomy&Astrophysics University of TorontoToronto ON M5S 3H4Canada Dunlap Institute for Astronomy&Astrophysics University of TorontoToronto ON M5S 3H4Canada School of mathematics and Physics The University of QueenslandSt.Lucia QLD 4072Australia Instituto de Alta Investigación Universidad de TarapacáAricaChile CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Instituto de Astrofísica Departamento de Ciencias FísicasFacultad de Ciencias ExactasUniversidad Andres BelloSantiagoChile Instituto de Astronomía Universidad Católica del NorteAntofagastaChile

Star clusters were historically considered simple stellar populations,with all stars sharing the same age and initial chemical composition.However,the presence of chemical anomalies in globular clusters(GCs),called multiple stellar populations(MPs),has challenged star formation theories in dense environments.Literature studies show that mass,metallicity,and age are likely controlling parameters for the manifestation of MPs.Identifying the limit between clusters with/without MPs in physical parameter space is crucial to reveal the driving mechanism behind their presence.In this study,we look for MP signals in Whiting 1,which is traditionally considered a young GC.Using the Magellan telescope,we obtained low-resolution spectra withinλλ=3850-5500?for eight giants of Whiting 1.We measured the C and N abundances from the CN and CH spectral indices.C and N abundances have variations comparable with their measurement errors(~0.1 dex),suggesting that MPs are absent from Whiting 1.Combining these findings with literature studies,we propose a limit in the metallicity vs.cluster compactness index parameter space,which relatively clearly separates star clusters with/without MPs(GCs/open clusters).This limit is physically motivated.On a larger scale,the galactic environment determines cluster compactness and metallicity,leading to metal-rich,diffuse,old clusters formed ex situ.Our proposed limit also impacts our understanding of the formation of the Sagittarius dwarf galaxy:star clusters formed after the first starburst(age≤8-10 Gyr).These clusters are simple stellar populations because the enriched galactic environment is no longer suitable for MP formation.

关键词： stellar galactic galaxy