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Bioactive Materials 2020年第1期5卷 26-33页

作者： Afrah Al Hegy Ryan Smith eric R.Gauthier joy e.gray-munro Dept.of Chemistry and Biochemistry Laurentian UniversitySudburyOntarioP3E 2C6Canada

Magnesium and its alloys are promising candidates for a new generation of biodegradable metals in orthopaedic applications due to their excellent biocompatibility,biodegradability,and mechanical properties that are similar to natural ***,direct in vitro assessment of these materials in the presence of cells is complicated by degradation products from the alloy that lead to a false positive for the most commonly used cell adhesion and cell proliferation *** this paper,a cyanine dye was used to quantitatively evaluate the in vitro biocompatibility of a Mg AZ31 alloy by both direct and indirect *** cytotoxicity of the corrosion products was evaluated via an indirect method;a 25%decrease in cell viability compared to control samples was ***,direct assessment of cell adhesion and proliferation showed a statistically significant increase in cell number at the surface after 72 *** addition,the degradation rate and surface characteristics of the Mg AZ31 alloy were evaluated for both direct and indirect *** degradation rate was unaffected by the presence of cells while evidence of an increase in calcium phosphate deposition on the magnesium alloy surface in the presence of cells was *** study demonstrates that a cyanine dye based assay provides a more accurate assessment of the overall in vitro biocompatibility of biodegradable metals than the more commonly used assays reported in the literature to date.

关键词： Magnesium alloys Biocompatibility Direct method Indirect method Cyanine dye Cell adhesion Cell proliferation Cytotoxicity

Influence of mixed organosilane coatings with variable RGD surface densities on the adhesion and proliferation of human osteosarcoma Saos-2 cells to magnesium alloy AZ31

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Bioactive Materials 2017年第1期2卷 35-43页

作者： Xiaoxi Yang Afrah Al Hegy eric R.Gauthier joy gray-munro Dept.of Chemistry and Biochemistry Laurentian UniversitySudburyOntarioP3E 2C6Canada

In the last decade,the use of magnesium and its alloys as biodegradable implant materials has become increasingly ***,surface modification of these materials to control the degradation rate in the early stages of healing and improve their biocompatibility is crucial to the successful implementation of magnesium alloy implants in *** adhesion and proliferation at the implant surface is a vital factor for successful integration of a biomaterial within the *** accomplish this task by binding to ligands such as the arginine-glycine-aspartic acid peptide sequence(RGD)commonly found on adhesive proteins present in the extracellular *** this paper,we report a biomimetic surface modification strategy involving deposition of a mixed organosilane layer on Mg AZ31 followed by covalent immobilization of RGD peptides through a heterobifunctional cross-linker *** results indicate that with optimized deposition conditions uniform organosilane coatings were successfully deposited on the Mg AZ31 ***,we have demonstrated that the surface density of immobilized RGD can be varied by depositing organosilane layers from solutions containing two different organosilanes in specified *** in cell adhesion and cell proliferation were observed on the surface modified substrates.

关键词： Magnesium alloys Biodegradable Biomimetic RGD peptide Surface modification Cell adhesion Organosilane

Analysis of cellulolytic and hemicellulolytic enzyme activity within the Tipula abdominalis （Diptera： Tipulidae） larval gut and characterization of Crocebacterium ilecola gen. nov., sp. nov., isolated from the Tipula abdominalis larval hindgut

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Insect Science 2010年第3期17卷 291-302页

作者： Theresa e. Rogers joy Doran-Peterson Microbiology Department University of Georgia Athens Georgia USA

In forested stream ecosystems of the north and eastern United States, larvae of the aquatic crane fly Tipula abdominalis are important shredders of leaf litter detritus. T. abdominalis larvae harbor a dense and diverse microbial community in their hindgut that may aide in the degradation oflignocellulose. In this study, the activities ofcellulolytic and hemicellulolytic enzymes were demonstrated from hindgut extracts and from bacterial isolates using model sugar substrates. One of the bacterial isolates was further characterized as a member of the family Microbacteriaceae. Taxonomic position of the isolate within this family was determined by a polyphasic approach, as is commonly employed for the separation of genera within the family Microbacteriaceae. The bacterial isolate is Gramtype positive, motile, non-sporulating, and rod-shaped. The G ＋ C content of the DNA is 64.9 mol%. The cell wall contains B2y type peptidoglycan, D- and L-diaminobutyric acid as the diamino acid, and rhamnose as the predominant sugar. The predominant fatty acids are 12-methyltetradecanoic acid （ai-C15：0） and 14-methylhexadecanoic acid （ai-C17：0）. The isolate forms a distinct lineage within the family Microbacteriaceae, as determined by 16S rRNA sequence analysis. We propose the name Crocebacterium ilecola gen. nov., sp. nov., to accommodate this bacterial isolate. The type species is T202T （ATCC BAA-1359; GenBank Accession DQ826511）.

关键词： cellulolytic hemicellulolytic hindgut

Surface Modification of AZ91 Magnesium Alloy

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Surface Modification of AZ91 Magnesium Alloy

Mechanical characterization of rose bengal and green light crosslinked collagen scaffolds for regenerative medicine

Second International Conference on Magnesium(ICM 2006)

作者： joy gray Woo-Jae Cheong David Shoesmith Integrated Manufacturing Technologies Institute National Research Council Canada 800 Collip Circle London Ontario N6G 4X8 Chemistry Department University of Western Ontario London Ontario N6A 5B7 Canada Chemistry Department University of Western Ontario London Ontario N6A 5B7 Canada

Mg is the lightest structural metal with the highest specific strength. It is therefore considered as a solution for vehicular mass reduction so as to reduce the fuel consumption and greenhouse gas emission. Unfortunately, Mg and its alloys are highly susceptible to corrosion, particularly in salt-spray conditions. This has limited its use in the automotive and aerospace industries, where exposure to harsh service conditions is unavoidable. To improve its corrosion resistance it is viable to apply a desirable engineering coating on the Mg *** communication discusses the practical aspects of magnesium surface modification based on our review. A novel immersion coating process is also discussed along with the corrosion behavior of coated and uncoated AZ91 magnesium alloy.

关键词： AZ91 , Surface modification

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Regenerative Biomaterials 2021年第6期8卷 185-198页

作者： joy Braun Stefanie eckes Michelle Fiona Kilb Dirk Fischer Claudia eßbach Pol Maria Rommens Philipp Drees Katja Schmitz Daniela Nickel Ulrike Ritz Department of Orthopedics and Traumatology BiomaTiCSUniversity Medical CenterJohannes Gutenberg UniversityLangenbeckstraße 1Mainz 55131Germany Clemens-Schopf-Institute of Organic Chemistry and Biochemistry Technical University of DarmstadtAlarich-Weiss-Straße 4Darmstadt 64287Germany Berufsakademie Sachsen—Staatliche Studienakademie Glauchau University of Cooperative EducationKopernikusstraße 51Glauchau 08371Germany

Collagen is one of the most important biomaterials for tissue engineering *** its excellent biocompatibility,it shows the non-negligible disadvantage of poor mechanical *** crosslinking with rose bengal and green light(RGX)is an appropriate method to improve this *** development of collagen laminates is helpful for further adjustment of the mechanical properties as well as the controlled release of incorporated *** this study,we investigate the impact of crosslinking and layering of two different collagen scaffolds on the swelling behavior andmechanical behavior inmicro tensile tests to obtain information on its wearing comfort(stiffness,strength and ductility).The mechanical stability of the collagen material after degradation due to cell contact is examined using thickness *** is no linear increase or decrease due to layering homologous ***,a decrease in elongation at break,Young’s modulus and ultimate tensile strength are measured when the untreated monolayer is compared to the crosslinked ***,we can detect a connection between stability and cell *** results show that with variation in number and type of layers,collagen scaffolds with tailored mechanical properties can be *** a multi-layered structure enables the release of biomolecules into inner or outer layers for biomedical applications.

关键词： collagen type I collagen laminates rose bengal and green light crosslinking thickness analysis micro tensile testing cell-collagen interactions

Hospitalized for poverty:orthopaedic discharge delays due to financial hardship in a tertiary hospital in Northern Tanzania

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Global Health Research and Policy 2022年第1期7卷 204-211页

作者： joy e.Obayemi elizabeth B.Card Octavian Shirima Ajay Premkumar Honest Massawe Neil P.Sheth Perelman School of Medicine University of PennsylvaniaPhiladelphiaUSA Kilimanjaro Christian Medical Centre(KCMC) MoshiTanzania Hospital for Special Surgery NewYorkUSA Pennsylvania Hospital Hospital of the University of PennsylvaniaPhiladelphiaUSA

Background:Musculoskeletal injury contributes significantly to the burden of disease in Tanzania and other *** hospitals to cope financially with this burden,they often mandate that patients pay their entire hospital bill before leaving the *** creates a phenomenon of patients who remain hospitalized solely due to financial *** study aims to characterize the impact of this policy on patients and hospital systems in resource-limited ***:A mixed-methods study using retrospective medical record review and semi-structured interviews was conducted at a tertiary hospital in Moshi,*** regarding patient demographics,injury type,days spent in the ward after medical clearance for discharge,and hospital invoices were collected and analyzed for orthopaedic patients treated from November 2016 to June ***:346 of the 867 orthopaedic patients(39.9%)treated during this time period were found to have spent additional days in the hospital due to their inability to pay their hospital *** these patients,72 patient charts were *** 72 patients spent an average of 9 additional days in the hospital due to financial hardship(range:1-64 days;interquartile range:2-10.5 days).They spent an average of 112,958 Tanzanian Shillings(TSH)to pay for services received following medical clearance for discharge,representing 12.3%of the average total bill(916,840 TSH).646 hospital bed-days were spent on these 72 patients when they no longer clinically required hospitalization.7(9.7%)patients eloped from the hospital without paying and 24(33.3%)received financial assistance from the hospital’s social welfare ***:Many patients do not have the financial capacity to pay hospital fees prior to *** reality has added significantly to these patients’overall financial hardship and has taken hundreds of bed-days from other critically ill *** single-institution,cross-sectional study provides a deeper u

关键词： Global surgery Orthopedic injury Road traffic crash Health policy ethics Financial hardship LMIC

Seasonal dynamics,kinetics,and effects of 2-hydroxyestradiol-17βon some steroidogenic enzymes in the ovary of the catfish Heteropneustes fossilis

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Aquaculture and Fisheries 2022年第5期7卷 462-473页

作者： Tapan Kumar Chourasia Radha Chaube Keerikkattil Paily joy Department of Zoology Institute of ScienceBanaras Hindu UniversityVaranasi221005India Hokkaido University Fisheries Sciences.3-1-1 Minato-ChoHakodateHokkaido041-8611Japan. Department of Biotechnology Cochin University of Science and TechnologyKochi682022India

The synthesis of bioactive steroids is catalyzed by an array of enzymes of diverse properties and *** the present study,seasonal dynamics and kinetics of key steroidogenic enzymes,17α-hydroxylase(Cyp17a),3β-hydroxysteroid dehydrogenase(Hsd3b),20α-hydroxysteroid dehydrogenase(Hsd20a)and 20β-hydroxysteroid dehydrogenase(Hsd20b)were investigated in the female catfish Heteropneustes ***,the effects of the estrogen metabolite 2-hydroxyestradiol-17β(2-OHe2)and human chorionic gonadotropin(hCG)on activities of the above enzymes,cytochrome P450 aromatase(Cyp19a1),and steroid products including testosterone and cortisol were *** enzymes under investigation showed significant seasonal variations across the annual ovarian cycle with low activity in the gonad resting *** enzymes Hsd3b and Cyp17a showed high activity during early oogenesis but the activities of Hsd20a and Hsd20b were higher towards late oogenesis in the spawning ***3b and Cyp17a elicited high apparent Km values(low substrate affinity)and high apparent Vmax in the vitellogenic phase compared to the postvitellogenic ***20a did not elicit any significant differences in the kinetic parameters between the two ***20b showed high apparent Km values(low substrate affinity)and high Vmax in the postvitellogenic *** incubation of ovarian slices with 2-OHe2 for 24 h increased dose-dependently Hsd3b,Cyp17a,Hsd20a and Hsd20b activities,similar to *** levels of the corresponding C21 steroid products,progesterone(P4),17α-hydroxyprogesterone(17-OHP4),17,20α-dihydroxy-4-pregnen-3-one(17,20α-DP)and 17,20β-dihydoxy-4-pregnen-3-one(17,20β-DP),and cortisol were ***,2-OHe2 decreased significantly the C19 and C18 steroids,testosterone and e2 levels,and Cyp19a *** co-incubation with hCG and 2-OHe2 produced a synergistic effect on the enzyme activities except that of *** co-incubation reversed the inhibitory effect of *** data show that

关键词： Catfish ovary Steroidogenic enzyme activity and kinetics 2-Hydroxyestradiol-17β Steroidogenic shift Human chorionic gonadotropin

Morphologic Response of a River Channel to Sand Mining in River Tyaa,Kitui County,Kenya

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Journal of environmental & earth Sciences 2020年第2期2卷 12-18页

作者： Philip Gathogo Muiruri joy A.Obando Ishmail O.Mahiri Department of Geography Kenyatta UniversityKenya43844Nairobi

Over 40 billion tons of sand is mined worldwide every year which isestimated to be higher than the natural replacement rates. In Kenya, therate of sand mining is raising concerns over its environmental effects sinceit is not regulated. This paper presents findings on the geomorphic effectsof sand mining in the ephemeral River Tyaa channel in Kitui County. Thestudy adopts the concept of feedback response mechanism of a naturalgeomorphic system. Through purposive sampling River Tyaa was selectedfor the study, where rampant sand mining was reportedly taking *** sampling on the five sand mining sites identified came up with arepresentative site namely Kanginga on which systematic sampling wasapplied while collecting data at both the active and control sites. Dataon channel width, depth and slope angles was obtained through physicalmeasurements while data on quantity of sand mined was obtained fromMwingi Sand Mining Cooperative. Multiple logistic regression analysiswas used to analyse data whereby the model compared active and controlsites. Test results indicated that sand mining had significantly increasedriver channel’s width (O.R. =1.531), depth (O.R. =1.527) and slope angles(O.R. =1.634) at active mining sites compared to control sites as deducedfrom the respective Odds Ratios. It concluded that sand mining had alteredchannel’s morphology resulting to adverse environmental effects such asloss of riparian vegetation and channel incision. It recommended curbingof illegal sand mining through licencing operators and reducing quantity ofsand mined by closing some mines. Furthers, it recommended monitoringthrough regular environmental Impact Assessment (e.I.A) and Audit (e.A)to inform protection of the river system from degrading.

关键词： Channel incision ephemeral stream Morphologic response Sand mining Sustainable development

Insights into the role of major bioactive dietary nutrients in lamb meat quality:a review

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Journal of Animal Science and Biotechnology 2022年第4期13卷 951-966页

作者： JavierÁlvarez-Rodríguez Olaia Urrutia Sandra Lobón Guillermo Ripoll Juan Ramón Bertolín Margalida joy Departament de Ciència Animal Universitat de Lleida25198 LleidaSpain Departamento de Agronomía Biotecnología y AlimentaciónIS-FOOD InstituteEscuela Técnica Superior de Ingeniería Agronómica y BiocienciasUniversidad Pública de NavarraPamplonaSpain Centro de Investigación y Tecnología Agroalimentaria de Aragón(CITA) Avda.Montañana 93050059 ZaragozaSpain Instituto Agroalimentario de Aragón–IA2(CITA-Universidad de Zaragoza) Avda.Miguel Servet17750013 ZaragozaSpain.

Feed supplementation withα-linolenic acid(ALA)and linoleic acid(LA)increases their content in muscle,ALA increases n-3 polyunsaturated fatty acids and decrease n-6/n-3 ratio in muscle,and LA increases rumenic ***,high LA supplementation may have negative effects on lambs’lipid oxidative stability of *** the sources of ALA and LA are fed as fresh forage,the negative effects are counterbalanced by the presence of other bioactive compounds,as vitamin e(mainlyα-tocopherol)and polyphenols,which delay the lipid oxidation in *** is a wide consensus on the capability of vitamin e delaying lipid oxidation on lamb meat,and its feed content should be adjusted to the length of supplementation.A high dietary inclusion of proanthocyanidins,phenolic compounds and terpenes reduce the lipid oxidation in muscle and may improve the shelf life of meat,probably as a result of a combined effect with dietary vitamin ***,the recommended dietary inclusion levels depend on the polyphenol type and concentration and antioxidant capacity of the feedstuffs,which cannot be compared easily because no routine analytical grading methods are yet *** phenolic compounds content in dietary ingredients/supplements for lambs are reported,no specific association with animal physiology responses may be established.

关键词： Fatty acid Forage Oilseed Polyphenol Vitamin e

Short-Term Biochemical Impacts in Cyphoderus javanus Borner (Collembola) as Potential Biomarkers of Fly Ash and Heavy Metal Pollution in Tropical Lateritic Soil

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Journal of environmental Protection 2016年第1期7卷 1-13页

作者： Atreyee Sahana Vadakepuram Chacko joy Soil ecology Laboratory Department of Zoology (Centre for Advanced Studies) Visva-Bharati University West Bengal India

The detritivorous soil microarthropods are ideal models for environmental health assessment, but only scant information is available on their biomarker potentials against xenobiotics in the tropical edaphic conditions. This microcosm study has estimated short-term biochemical changes with respect to tissue nutrient levels and digestive enzyme activities in a near cosmopolitan Collembola Cyphoderus javanus Borner exposed to coal fly ash amended lateritic cropland soil (5% and 20% w/w i.e. 50 or 200 t ·ha-1), and cadmium sulphate (200 mg/kg soil)/lead acetate (200 mg/kg soil) treated sterile river sand. The levels of total tissue carbohydrates, proteins, free amino acids, and lipids decrease within 7 days in the specimens of fly ash (P α-amylase, cellulase and protease activities are also down regulated by fly ash and heavy metals (P erved the enzyme: protein ratios increase in fly ash treated sets and decrease in lead and cadmium treated specimens. Specimens in treated sets accumulate high levels of lead and cadmium within 15 days, which decrease subsequently probably due to elimination through frequent moulting. These short-term biochemical effects in Collembola have applied importance in C. javanus, as biomarkers for quick ecotoxicological assessments in the tropical agricultural soils.

关键词： Soil Collembola Tissue Nutrients Digestive enzyme Activity Biomarkers ecotoxicology