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Engineering（科研） 2015年第7期7卷 434-445页

作者： Joseph Babalola Agboola Oladiran Abubakre Kamardeen Edeki Mudiare michael bolaji adeyemi Department of Mechanical Engineering Federal University of Technology Minna Nigeria

Theoretical analysis of the effects of velocity of impact using suitable heat transfer equations expressed in forms of finite difference method was developed and used to determine their effects on the characteristic cooling parameters during quenching process. Various velocities of impact obtained by varying the heights of specimen drops were also used to experimentally determine their effects on characteristic cooling parameters and mechanical properties of medium carbon steel using water as the quenching medium. At height of drop of 0.5 m, 1.0 m, 1.5 m, and 2.0 m, the tensile strength of the material is 410.4, 496.12, 530.56, and 560.40 N/mm2 respectively. The corresponding hardness values are 42.4, 45.2, 46.2, 50.5 HRC respectively. It is found that as the velocity of impact increases, maximum cooling rate increases. Hardness and ultimate tensile strength also increase. There are good agreements between theoretical and experimentally determined values of critical cooling parameters of water during quenching operations.

关键词： Quenching Modeling Velocity Impact Mechanical Properties Steel

Determining the Effect of Cutting Fluids on Surface Roughness in Turning AISI 1330 Alloy Steel Using Taguchi Method

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Modern Mechanical Engineering 2016年第2期6卷 51-59页

作者： Onyemachi Joachim Onuoha James Oseni Abu Sunday Albert Lawal Edeki Mudiare michael bolaji adeyemi Department of Mechanical Engineering School of Engineering and Engineering Technology Federal University of Technology Minna Nigeria

Taguchi method has been employed to investigate the effects of cutting fluids on surface roughness in turning AISI 1330 alloy steel, using manually operated lathe machine. Experiments have been conducted using L27 (34) orthogonal array and each experiment was repeated three times and each test used a new cutting tool, High Speed Steel (HSS), to ensure accurate readings of the surface roughness. The statistical methods of Signal-to-Noise (S/N) ratio and the Analysis of Variance (ANOVA) were applied to investigate effects of cutting speed, feed rate and depth of cut on surface roughness under different cutting fluids. Minitab 14 software was used to analyze the effect of variables on the surface roughness. Results obtained indicated that optimal variables for the minimum surface roughness were cutting speed of 35 m/min (level 2), feed of 0.124 mm/rev (level 1), depth of cut of 0.3 mm (level 1) and a cutting fluid with a viscosity of 2.898 mm2/s (level 3). Hence, the optimal parameters to obtain better surface roughness of the workpiece material were obtained when groundnut oil based cutting fluid was used. Analysis of variance shows that feed rate has the most significant effect on surface roughness.

关键词： Taguchi Method Surface Roughness Turning Process Cutting Fluid

Performance Assessment of Selected Nigerian Vegetable Oils as Quenching Media in Hardening Process for Medium Carbon Steel

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Journal of Minerals and Materials Characterization and Engineering 2015年第2期3卷 85-93页

作者： Joseph Babalola Agboola Oladiran Abubakre Kamardeen Edeki Mudiare michael bolaji adeyemi Samuel Ayo Afolabi Department of Mechanical Engineering Federal University of Technology Minna Nigeria Department of Civil and Chemical Engineering University of South Africa (Unisa) Johannesburg South Africa

A comparative study was carried out to investigate the suitability of some selected Nigerian vegetable oils as alternative quenchant to SAE40 engine oil for industrial heat treatment of Medium Carbon steels. The study involved the characterization of physicochemical properties and fatty acid profile of cotton seed oil, palm kernel oil, neem seed oil and palm oil. The quenching performance of these vegetable oils was conducted at quenchant bath temperatures of 34oC, 50oC, 70oC, and 100oC. SAE40 engine oil (Standard quenchant) and tap water served as control. The effect of cooling rates of the quenching media on mechanical properties and microstructure of the quenched steel samples were investigated. The results obtained show that the different vegetable oils have different viscosity and viscosity-temperature behavior just as their molecular structures were different. The mechanical properties of the as-quenched specimens in these oils show that the hardness of steel quenched in palm kernel oil was highest 40.85HRC. As received sample absorbed the highest amount of energy (183 J) before fracture while sample quenched in water absorbs least energy (28 J). Hence vegetable oil is suitable as alternative quenchant to petroleum based SAE40 engine oil for quenching medium carbon steels, without cracking or distortion, the most suitable among them being palm kernel oil.

关键词： Quenching Vegetable Oil Fatty Acid Mechanical Properties Microstructure

Like a G6-nal:transcriptional control of G-protein coupled receptors during oligodendroglial development

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Neural Regeneration Research 2025年第7期20卷 2001-2002页

作者： Tim Aberle michael Wegner Institut für Biochemie Friedrich-Alexander-Universität Erlangen-NürnbergErlangenGermany

Multilayered control of myelination:Quick,saltatory conduction of action potentials along nerve fibers requires the electrical insulation of axons by myelinating *** the central nervous system,this role is taken up by *** are marked by the expression of the lineage determinants Sox10 and Olig2 and arise from oligodendrocyte precursor cells(OPCs)during embryonal *** the majority of OPCs differentiate into mature oligodendrocytes when nearby axonal segments require myelination,a small subpopulation of OPCs persist as a progenitor ***,the timing of myelination and maintenance of the OPC pool both need to be precisely *** transcription factors either positively or negatively affect oligodendrocyte differentiation and maintenance of the OPC pool as components of a complex gene regulatory network(reviewed in Sock and Wegner,2021).Network activity is additionally influenced by extracellular signaling molecules that bind to receptors on the oligodendroglial cell surface and activate intracellular signaling *** the receptors are linked to the network is poorly understood so far,but pivotal to understanding the overall regulation of central nervous system(CNS)myelination in response to environmental *** insights were recently gained for Gpr37(Schmidt et al.,2024),a G-protein coupled receptor(GPCR)with known relevance in differentiating oligodendrocytes(Yang et al,2016).

关键词： gained insulation conduction

Evaluation of empirical estimation of uniaxial compressive strength of rock using measurements from index and physical tests

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 256-268页

作者： adeyemi Emman Aladejare Oulu Mining School University of OuluPentti Kaiteran Katu 1Oulu90014Finland

The uniaxial compressive strength(UCS) of rock is an important parameter required for design and analysis of rock structures,and rock mass *** compression test is the direct method to obtain the UCS ***,these tests are generally tedious,time-consuming,expensive,and sometimes impossible to perform due to difficult rock ***,several empirical equations have been developed to estimate the UCS from results of index and physical tests of ***,numerous empirical models available in the literature often make it difficult for mining engineers to decide which empirical equation provides the most reliable estimate of *** study evaluates estimation of UCS of rocks from several empirical *** study uses data of point load strength(Is(50)),Schmidt rebound hardness(SRH),block punch index(BPI),effective porosity(n) and density(ρ)as inputs to empirically estimate the *** estimated UCS values from empirical equations are compared with experimentally obtained or measured UCS values,using statistical *** shows that the reliability of UCS estimated from empirical equations depends on the quality of data used to develop the equations,type of input data used in the equations,and the quality of input data from index or physical *** results show that the point load strength(Is(50)) is the most reliable index for estimating UCS among the five types of tests *** of type-specific nature of rock,restricting the use of empirical equations to the similar rock types for which they are developed is one of the measures to ensure satisfactory prediction performance of empirical equations.

关键词： Uniaxial compressive strength(UCS) Empirical equation Index test Physical test Uniaxial compression test Statistical analysis

Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease

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Neural Regeneration Research 2025年第1期20卷 174-180页

作者： Yinglong Miao michael S.Wolfe Computational Medicine Program and Department of Pharmacology University of North Carolina–Chapel HillChapel HillNCUSA Department of Medicinal Chemistry University of KansasLawrenceKSUSA

γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface *** inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as ***,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-*** this review,we focus on recent studies of structural dynamic mechanisms ofγ-*** mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics *** an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental *** approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-*** addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is ***,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations

关键词： Alzheimer’s disease amyloid precursor protein cryo-EM structures drug design intramembrane proteolysis molecular dynamics Notch

Type 1 diabetes in a Nigerian family-occurrence in three out of four siblings: A case report

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World Journal of Diabetes 2019年第10期10卷 511-516页

作者： michael adeyemi Olamoyegun Oluwabukola Ayodele Ala Department of Internal Medicine EndocrinologyDiabetes&Metabolism UnitCollege of Health SciencesLadoke Akintola University of Technology(LAUTECH)/LAUTECH Teaching HospitalOgbomoso 240222Oyo StateNigeria Department of Internal Medicine EndocrinologyDiabetes&Metabolism UnitBOWEN University Teaching Hospitaland College of Health SciencesBOWEN UniversityIwo 232101Osun StateNigeria

BACKGROUND Most occurrences of type 1 diabetes cases in any population are sporadic rather than ***,type 1 diabetes among siblings is a rare *** more rare is for three or more siblings to develop type 1 *** this report,we describe a case of a Nigerian family in which type 1 diabetes occurred in three siblings among four children with neither parent having *** three siblings are positive for glutamic acid decarboxylase and anti-islet cell *** SUMMARY There were four siblings(three males and one female)born to a couple without a diagnosis of *** eldest child(male)was diagnosed with diabetes at the age of 15,the second child(female)was diagnosed at the age of 11 and the fourth child(male)was diagnosed at the age of *** the siblings presented with similar osmotic symptoms and were diagnosed of diabetic *** of them had markedly reduced serum C-peptide levels with high levels of glutamic acid decarboxylase and insulinoma-associated protein-2 *** could not perform genetic analysis of HLA-DR,DQ and CTLA4 in the siblings as well as the parents;hence haplotypes could not be *** parents of the probands have no prior history of diabetes,and their blood glucose and glycated hemoglobin levels were within normal *** third child(male)has no history suggestive of diabetes,and his blood glucose and glycated hemoglobin have remained within normal *** Although the occurrence of type 1 diabetes in proband siblings is uncommon,screening for diabetes among siblings especially with islet autoantibodies should be encouraged.

关键词： Type 1 diabetes Siblings Case report Nigerian Family

NECAB family of neuronal calcium-binding proteins in health and disease

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Neural Regeneration Research 2025年第5期20卷 1236-1243页

作者： Diones Bueno michael K.E.Schafer Sudena Wang michael J.Schmeisser Axel Methner Institute for Molecular Medicine University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Department of Anesthesiology University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Institute of Anatomy University Medical Center of the Johannes Gutenberg-UniversityMainzGermany

The N-terminal EF-hand calcium-binding proteins 1–3(NECAB1–3) constitute a family of predominantly neuronal proteins characterized by the presence of at least one EF-hand calcium-binding domain and a functionally less well characterized C-terminal antibiotic biosynthesis monooxygenase domain. All three family members were initially discovered due to their interactions with other proteins. NECAB1 associates with synaptotagmin-1, a critical neuronal protein involved in membrane trafficking and synaptic vesicle exocytosis. NECAB2 interacts with predominantly striatal G-protein-coupled receptors, while NECAB3 partners with amyloid-β A4 precursor protein-binding family A members 2 and 3, key regulators of amyloid-β production. This demonstrates the capacity of the family for interactions with various classes of proteins. NECAB proteins exhibit distinct subcellular localizations: NECAB1 is found in the nucleus and cytosol, NECAB2 resides in endosomes and the plasma membrane, and NECAB3 is present in the endoplasmic reticulum and Golgi apparatus. The antibiotic biosynthesis monooxygenase domain, an evolutionarily ancient component, is akin to atypical heme oxygenases in prokaryotes but is not wellcharacterized in vertebrates. Prokaryotic antibiotic biosynthesis monooxygenase domains typically form dimers, suggesting that calcium-mediated conformational changes in NECAB proteins may induce antibiotic biosynthesis monooxygenase domain dimerization, potentially activating some enzymatic properties. However, the substrate for this enzymatic activity remains uncertain. Alternatively, calcium-mediated conformational changes might influence protein interactions or the subcellular localization of NECAB proteins by controlling the availability of protein–protein interaction domains situated between the EF hands and the antibiotic biosynthesis monooxygenase domain. This review summarizes what is known about genomic organization, tissue expression, intracellular localization, interac

关键词： calcium EF hand mitochondria nervous system signal transduction

Performance and sustainability overview of alkali-activated self-compacting concrete

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Waste Disposal and Sustainable Energy 2020年第3期2卷 165-175页

作者： adeyemi Adesina Department of Civil and Environmental Engineering University of WindsorWindsorCanada

Self-compacting concrete(SCC)has gained huge attention recently due to its high workability which eliminates the need for vibration and makes its placement easier compared to conventional ***,the production of Portland cement(PC)which is the main binder in SCC is energy-intensive and one of the major contributors to the world’s carbon dioxide *** the other hand,the use of alkali-activated binders(AABs)in concrete has been reported to reduce the energy consumption and carbon emission of concrete by more than 50%.Therefore,the use of AAB as a binder in SCC can help to achieve an eco-friendlier *** paper gives a short overview of the performance of SCC made with *** effect of various factors on the performance of alkali-activated self-compacting concrete(AASCC)was discussed and a simplified sustainability assessment of AASCC was carried *** from this paper showed that AASCC with acceptable fresh and hardened properties can be achieved with the proper selection of *** addition,the evaluation of the embodied energy and carbon of different types of concrete showed that AASCC is more ***,more research in this field is required to encourage its universal acceptance and large-scale application.

关键词： Concrete Self-compacting concrete Alkali-activated concrete Sustainability Clean technology

Small extracellular vesicles derived from cerebral endothelial cells with elevated microRNA 27a promote ischemic stroke recovery

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Neural Regeneration Research 2025年第1期20卷 224-233页

作者： Yi Zhang Zhongwu Liu michael Chopp michael Millman Yanfeng Li Pasquale Cepparulo Amy Kemper Chao Li Li Zhang Zheng Gang Zhang Department of Neurology Henry Ford HospitalDetroitMIUSA Department of Physics Oakland UniversityRochesterMIUSA Department of Pathology Henry Ford HospitalDetroitMIUSA Division of Pharmacology Department of NeuroscienceReproductive and Dentistry SciencesSchool of MedicineUniversity of Naples“Federico Ⅱ”NaplesItaly

Axonal remodeling is a critical aspect of ischemic brain repair processes and contributes to spontaneous functional *** previous in vitro study demonstrated that exosomes/small extracellular vesicles(sEVs)isolated from cerebral endothelial cells(CEC-sEVs)of ischemic brain promote axonal growth of embryonic cortical neurons and that microRNA 27a(miR-27a)is an elevated miRNA in ischemic *** the present study,we investigated whether normal CEC-sEVs engineered to enrich their levels of miR-27a(27a-sEVs)further enhance axonal growth and improve neurological outcomes after ischemic stroke when compared with treatment with non-engineered CEC-sEVs.27a-sEVs were isolated from the conditioned medium of healthy mouse CECs transfected with a lentiviral miR-27a expression *** EVs isolated from CECs transfected with a scramble vector(Scra-sEVs)were used as a *** male mice were subjected to permanent middle cerebral artery occlusion and then were randomly treated with 27a-sEVs or *** array of behavior assays was used to measure neurological *** with treatment of ischemic stroke with Scra-sEVs,treatment with 27a-sEVs significantly augmented axons and spines in the peri-infarct zone and in the corticospinal tract of the spinal grey matter of the denervated side,and significantly improved neurological *** vitro studies demonstrated that CEC-sEVs carrying reduced miR-27a abolished 27a-sEV-augmented axonal *** analysis revealed that 27a-sEVs systemically administered preferentially localized to the pre-synaptic active zone,while quantitative reverse transcription-polymerase chain reaction and Western Blot analysis showed elevated miR-27a,and reduced axonal inhibitory proteins Semaphorin 6A and Ras Homolog Family Member A in the peri-infarct *** of the Clathrin-dependent endocytosis pathway substantially reduced neuronal internalization of *** data provide evidence that 27a-sEVs have

关键词： axonal remodeling cerebral endothelial cells exosomes miR-27a mitochondria Semaphorin 6A small extracellular vesicles stroke