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Adjusting the physico-chemical properties of collagen scaffolds to accommodate primary osteoblasts and endothelial cells

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Regenerative Biomaterials 2023年第1期10卷 590-602页

作者： Nima Meyer daniel V.Bax Jochen Beck Ruth e.Cameron Serena M.Best Department of Materials Science and Metallurgy University of CambridgeCambridge CB30FSUK Geistlich Pharma AG Product DevelopmentWolhusenSwitzerland

Collagen-based biomaterials are used widely as tissue engineering scaffolds because of their excellent bioactivity and their similarity to the natural *** regeneration of healthy bone tissue requires simultaneous support for both osteoblasts and,where angiogenesis is intended,endothelial *** it is important to tailor carefully the biochemical and structural characteristics of the scaffold to suit the needs of each cell *** work describes for the first time a systematic study to gain insight into the cell type-specific response of primary human osteoblast(hOBs)and human dermal microvascular endothelial cells(HDMeCs)to insoluble collagen-based *** behaviour was evaluated on both 2D films and 3D scaffolds,produced using *** collagen was cross-linked at various eDC/NHS concentrations and mono-cultured with hOBs and HDMeCs to assess the effect of architectural features and scaffold stabilization on cell *** was observed that 3D scaffolds cross-linked at 30%of the standard conditions in literature offered an optimal combination of mechanical stiffness and cellular response for both cell types,although endothelial cells were more sensitive to the degree of cross-linking than *** features have a time-dependent impact on the cell migration profile,with alignment being the most influential parameter overall.

关键词： angiogenesis collagen scaffolds cell migration eDC/NHS cross-linking

The present and the future in the diagnosis and management of celiac disease

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Gastroenterology Report 2015年第1期3卷 3-11页

作者： Natalia e.Castillo Thimmaiah G.Theethira daniel A.Leffler Division of Gastroenterology Beth Israel Deaconess Medical CenterBostonMAUSA

Celiac disease is an autoimmune enteropathy caused by gluten in genetically predisposed *** celiac disease,adaptive and innate immune activation results in intestinal damage and a wide range of clinical *** the past,celiac disease was thought to result in signs and symptoms solely related to the gastrointestinal ***,more than half of the adult population presents with extra-intestinal manifestations that can also be expected to improve on a gluten-free *** this reason,it is recommended that physicians have a low threshold of suspicion for celiac *** knowledge of the immune pathogenesis of this autoimmune disease has served as a catalyst for the development of novel diagnostic tools and *** the years,highly sensitive and speciﬁc serological assays,in addition to genetic markers,have been found to target speciﬁc steps in the cascade pathway of celiac *** the advent of the gluten challenge has enabled experts to design diagnostic algorithms and monitor clinical responses in clinical *** gluten challenge has provided substantial beneﬁt in the advance of novel therapeutics as an adjuvant treatment to the gluten free ***,a strict gluten-free diet is highly burdensome to patients and can be limited in its efﬁ*** therapies-including gluten modiﬁcation,modulation of intestinal permeability and immune response--could be central to the future treatment of celiac disease.

关键词： celiac disease gluten-free diet autoimmune diseases

empirical studies of escape behavior find mixed support for the race for life model

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Current Zoology 2022年第3期68卷 305-313页

作者： Kwasi WReNSFORD Jahaziel GUTIeRReZ William e.COOPeRJR daniel T.BLUMSTeIN Department of Integrative Biology Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCA 94720USA The Rocky Mountain Biological Laboratory Crested ButteCO 81224USA Department of Biology Indiana University Purdue University Fort WayneFort WayneIN 46805USA Department of ecology and evolutionary Biology University of California6121 Young Drive SouthLos AngelesCA 90095-1606USA

escape theory has been exceptionally successful in conceptualizing and accurately predicting effects of numerous factors that affect predation risk and explaining variation in flight initiation distance(FID;predator–prey distance when escape begins).Less explored is the relative orientation of an approaching predator,prey,and its eventual *** relationship between an approaching threat and its refuge can be expressed as an angle we call the“interpath angle”or“Φ,”which describes the angle between the paths of predator and prey to the prey’s refuge and thus expresses the degree to which prey must run toward an approaching *** general,we might expect that prey would escape at greater distances if they must flee toward a predator to reach its ***“race for life”model makes formal predictions about howΦshould affect *** evaluated the model by studying escape decisions in yellow-bellied marmots Marmota flaviventer,a species which flees to *** found support for some of the model’s predictions,yet the relationship betweenΦand FID was less *** may not assessΦin a continuous fashion;but we found that binning angle into 445°bins explained a similar amount of variation as models that analyzed angle *** studies ofΦ,especially those that focus on how different species perceive relative orientation,will likely enhance our understanding of its importance in flight decisions.

关键词： antipredator behavior escape behavior escape theory escape trajectory race for life model

Fungal contamination of stored automobile-fuels in a tropical environment

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Journal of environmental Sciences 2010年第10期22卷 1595-1601页

作者： Carlos e.Rodríguez-Rodríguez evelyn Rodríguez Rigoberto Blanco Ivannia Cordero daniel Segura Research Center in Tropical Diseases and Laboratory of Research in Anaerobic Bacteriology Faculty of MicrobiologyUniversity of Costa Rica Department of Chemical engineering School of EngineeringAutonomous University of Barcelona Research Center in electrochemistry and Chemical energy University of Costa Rica

Because of the lack of reports, the base levels of microbial contamination on stored fuels are unknown in tropical regions and it is unclear whether these levels have some influence on fuel quality parameters. Therefore, fungal quality in automobile fuels stored across Costa Rican territory was evaluated during two years according to the standard ASTM D6974-04. For a total of 96 samples, counts and identification of molds and yeasts were performed on regular gas, premium gas and diesel taken from the bottom and superior part of the container tanks. The highest contamination was found on the bottom of the tanks, where an aqueous phase was usually identified, showing populations over the ones present in the hydrocarbon itself （up to 108 CFU/L）. Diesel was the most contaminated fuel （up to 107 CFO/L）; however, an alteration on the physicochemical parameters was not observed in any kind of fuel. Seventy-five mold strains were isolated, Penicillium sp. being the most common genus （45.8% of the samples）, and ten yeast strains, from the genera Candida sp. and Rhodotorula sp. Four of the yeasts were able to grow on diesel as the sole carbon source, at concentrations ranging from 0.5% to 25%. Increasing the frequency of tank cleaning, adding antimicrobial agents and monitoring microbial populations are recommended strategies to improve microbial quality of stored fuels.

关键词： fuel microbial contamination biodegradation molds yeasts

Adsorptive removal of resorcinol on a novel ordered mesoporous carbon(OMC) employing COK-19 silica scaffold:Kinetics and equilibrium study

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Journal of environmental Sciences 2019年第1期31卷 307-317页

作者： Zaki Uddin Ahmad Qiyu Lian Mark e.Zappi Prashanth R.Buchireddy daniel Dianchen Gang Department of Civil engineering University of Louisiana at Lafayette Center for environmental Technology The Energy Institute of Louisiana Department of Chemical engineering University of Louisiana at Lafayette

Phenolic compounds and their derivatives have been found in industrial wastewater, which pose threats to the natural environment. Ordered mesoporous carbon(OMC) has been identified as an ideal adsorbent possessing high specific surface area and large pore volume to alleviate these pollutants. A novel ordered mesoporous carbon was prepared using COK-19 template with the cubic Fm3 m structure for the first time. Ordered mesoporous silica COK-19 was synthesized and reported in 2015. Sucrose as the carbon precursor was impregnated into the mesopores of silica and converted to carbon through carbonization process using sulfuric acid as a catalyst. Ordered mesoporous carbon was obtained after the removal of silica framework using hydrofluoric acid. Boric acid was employed for the preparation of OMCs with tunable pore sizes in the range of 6.9–16.6 nm. Several characterization techniques such as nitrogen adsorption–desorption isotherms, transmission electron microscope(TeM), Fourier transform infrared spectroscopy, Boehm titration and elemental analysis were employed to characterize the OMCs. The pore size analysis and TeM images confirmed that OMC has replicated the mesostructure of the COK-19. Results obtained from adsorption kinetics and isotherms suggest that the Pseudo-second-order model and Langmuir isotherm well described the experimental data.

关键词： Ordered mesoporous carbon COK-19 TeM image Resorcinol Adsorption isotherm Adsorption kinetics

An experimental and theoretical investigation of a small,high aspect-ratio,free-piston,two-stroke engine

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Propulsion and Power Research 2020年第4期9卷 326-343页

作者： Chiluwata e.Lungu Mael Disseau daniel C.Stubbs Jechiel Jagoda David e.Scarborough General electric Company GreenvilleSouth Carolina29615USA Georgia Institute of Technology AtlantaGeorgia30332USA Truett McConnel University ClevelandGeorgia30528USA Auburn University AuburnAlabama36849USA

This paper presents a design for a novel,palm sized,high-aspect-ratio *** simplify fabrication and keep the device unobtrusive,a design incorporating a two-cycle engine having a flat,rectangular piston with spring return was *** experimental engine based on this concept producing a significant amount of useful work was *** results were encouraging,this geometry raised many issues to be investigated and resolved,including the effects of piston sealing,scavenging,heat losses,and combustion *** to the complex interplay between these effects,experimental investigation was time consuming and simple models were found to be ***,a more complex theoretical model accounting for these effects was developed and used to evaluate the sensitivity of engine performance to each of these *** predictions of this model were used to develop recommendations for improving the experimentally developed engine.

关键词： Micro-combustion Power generation Free-piston engine Internal combustion engine Palm power

estimating the geographic range of a threatened shark in a data-poor region： Cetorhinus maximus in the South Atlantic Ocean

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Current Zoology 2015年第5期61卷 811-826页

作者： Luis O. LUCIFORA Santiago A. BARBINI edgardo e. DI GIACOMO Juan A. WAeSSLe daniel e. FIGUeROA Instituto de Biologia Subtropical - Iguazu Consejo Nacional de Investigaciones Cientificas y Tecnicas Universidad Nacional de Misiones Puerto Iguazu Misiones Argentina Laboratorio de Ictiologia Instituto de Investigaciones Marinas y Costeras Consejo Nacional de Investigaciones Cientificas y Tecnicas Universidad Nacional de Mar del Plata Mar del Plata Provincia de Buenos Aires Argentina Grupo Condros Instituto de Biologia Marina y Pesquera "Almirante Stomi" Universidad Nacional del Comahue San Antonio Oeste Rio Negro Argentina Instituto Nacional de Investigacion y Desarrollo Pesquero Mar del Plata Provincia de Buenos Aires Argentina

The distribution of the planktivorous basking shark Cetorhinus maximus is influenced by zooplankton abundance at small scales and temperature at medium scales in the North Atlantic. Here, we estimate the distribution of basking sharks on South Atlantic continental shelves, and the relative importance of chlorophyll concentration, as a proxy for zooplankton abun- dance, and temperature in determining habitat suitability for basking sharks at large scales. We used maximum entropy （Maxent） and maximum likelihood （MaxLike） species distribution modelling to test three hypotheses： the distribution of basking sharks is determined by （1） temperature, （2） chlorophyll concentration, or （3） both chlorophyll and temperature, while considering other factors, such as oxygen and salinity. Off South America, basking shark habitat included subtropical, temperate and cool-temperate waters between approximately 20°S and 55°S. Off Africa, basking shark habitat was limited to cool-temperate waters off Namibia and southern South Africa. MaxLike models bad a better fit than Maxent models. The best model included minimum chlorophyll concentration, dissolved oxygen concentration, and sea surface temperature range, supporting hypothesis 3. However, of all variables included in the best model, minimum chlorophyll concentration had the highest influence on basking shark distribution. Unlike the North Atlantic distribution, the South Atlantic distribution of basking sharks includes subtropical and cool-temperate waters. This difference is explained by high minimum chlorophyll concentration off southern Brazil as compared to North Atlantic subtropical areas. Observations in other regions of the world support this conclusion. The highest habitat suitability for basking sharks is located close to nearshore areas that experience high anthropogenic impact [Current Zoology 61 （5）： 811-826, 2015].

关键词： Basking shark Chondrichthyes Geographic range Maxent MaxLike Southern Hemisphere

Recent developments in topoisomerase-targeted cancer chemotherapy

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Acta Pharmaceutica Sinica B 2018年第6期8卷 844-861页

作者： Kirk e.Hevener Tatsiana A.Verstak Katie e.Lutat daniel L.Riggsbee Jeremiah W.Mooney Department of Pharmaceutical Sciences University of Tennessee Health Science Center

The DNA topoisomerase enzymes are essential to cell function and are found ubiquitously in all domains of life. The various topoisomerase enzymes perform a wide range of functions related to the maintenance of DNA topology during DNA replication, and transcription are the targets of a wide range of antimicrobial and cancer chemotherapeutic agents. Natural product-derived agents, such as the camptothecin, anthracycline, and podophyllotoxin drugs, have seen broad use in the treatment of many types of cancer. Selective targeting of the topoisomerase enzymes for cancer treatment continues to be a highly active area of basic and clinical research. The focus of this review will be to summarize the current state of the art with respect to clinically used topoisomerase inhibitors for targeted cancer treatment and to discuss the pharmacology and chemistry of promising new topoisomerase inhibitors in clinical and preclinical development.

关键词： Topoisomerase Inhibition Cancer Oncology Clinical Pre-clinical

extracellular matrix-templating fibrous hydrogels promote ovarian tissue remodeling and oocyte growth

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Bioactive Materials 2024年第2期32卷 292-303页

作者： Claire e.Nason-Tomaszewski emily e.Thomas daniel L.Matera Brendon M.Baker Ariella Shikanov Department of Biomedical engineering University of MichiganAnn ArborMI 48109USA Department of Chemical engineering University of MichiganAnn ArborMI 48109USA Department of Obstetrics and Gynecology University of MichiganAnn ArborMI 48109USA Cellular and Molecular Biology Program University of MichiganAnn ArborMI 48109USA

Synthetic matrices which mimic the extracellular composition of native tissue create a comprehensive model for studying development and ***,we have engineered a composite material which retains cell-secreted eCM for the culture of ovarian follicles by embedding electrospun dextran fibers functionalized with basement membrane binder(BMB)peptide in PeG *** the presence of eCM-sequestering fibers,encapsulated immature primordial follicles and ovarian stromal cells aggregated into large organoid-like structures with dense deposition of laminin,perlecan,and collagen I,leading to steroidogenesis and significantly greater rates of oocyte survival and *** determined that cell aggregation restored key cell-cell interactions critical for oocyte survival,whereas oocyte growth was dependent on cell-matrix interactions achieved in the presence of *** we have shown that sequestration and retention of cell-secreted eCM along synthetic fibers mimics fibrous eCM structure and restores the cell-cell and cell-matrix interactions critical for engineering an artificial ovary.

关键词： Biomimetic matrix Ovarian follicle Fibrous hydrogels