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Stem cell therapy for the treatment of Leydig cell dysfunction in primary hypogonadism

World Journal of Stem cells 2016年第10期8卷 306-315页

作者： taylor c peak Nora M Haney William Wang Kenneth J DeLay Wayne J Hellstrom Department of Urology School of MedicineTulane University

The production of testosterone occurs within the Leydig cells of the testes. When production fails at this level from either congenital, acquired, or systemic disorders,the result is primary hypogonadism. While numerous testosterone formulations have been developed, none are yet fully capable of replicating the physiological patterns of testosterone secretion. Multiple stem cell therapies to restore androgenic function of the testes are under investigation. Leydig cells derived from bone marrow, adipose tissue, umbilical cord, and the testes have shown promise for future therapy for primary hypogonadism. In particular, the discovery and utilization of a group of progenitor stem cells within the testes, known as stem Leydig cells(SLcs), has led not only to a better understanding of testicular development, but of treatment as well. When combining this with an understanding of the mechanisms that lead to Leydig cell dysfunction, researchers and physicians will be able to develop stem cell therapies that target the specific step in the steroidogenic process that is deficient. The current preclinical studies highlight the complex nature of regenerating this steroidogenic process and the problems remain unresolved. In summary, there appears to be two current directions for stem cell therapy in male primary hypogonadism. The first method involves differentiating adult Leydig cells from stem cells of various origins from bone marrow, adipose, or embryonic sources. The second method involves isolating, identifying, and transplanting stem Leydig cells into testicular tissue. Theoretically, in-vivo re-activation of SLcs in men with primary hypogonadism due to age would be another alternative method to treat hypogonadism while eliminating the need for transplantation.

关键词： Stem cell therapy Leydig cells Primary hypogonadism Stem Leydig cells Testosterone Bone marrow-derived stem cells Adipose-derived mesenchymal stem cells

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Impact of carbon-based nutrient enhancement on biofiltration performance for drinking water treatment

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Journal of Environmental Sciences 2019年第8期31卷 124-131页

作者： Yu Zhao Liz taylor-Edmonds Robert c.Andrews Department of civil and Mineral Engineering University of Toronto

Incorporation of a carbon-based nutrient enhancementstrategy for drinking water biofiltration is an attractive option, especially for source waters which contain recalcitrant organics. This study compared biofilters that were operated in parallel and individually enhanced with amino acids(including alanine, phenylalanine, and tryptophan), inulin, and sucrose to increase biomass concentration and promote biodegradation of dissolved organic carbon(DOc) in the source water, including disinfection by-product(DBP) precursors. Biomass activity was characterized by measuring adenosine tri-phosphate(ATP), dissolved oxygen(DO) consumption, and through the use of laccase and esterase enzyme assays. Performance was evaluated in terms of headloss,turbidity, p H, DOc, UV254, and DBP formation potential(DBP FP). The introduction of carbonbased nutrients significantly increased biomass activity, where ATP values peaked at 976 ng/g of filter media, 853 ng/g, and 513 ng/g for amino acids, inulin, and sucrose-spiked biofilters,respectively, while a non-spiked control only reached 104 ng/g. DO utilization by the enhanced biofilters was significantly higher than the control, with a strong correlation between ATP and DO uptake observed for all filters(R^2> 0.74). Laccase and esterase enzyme activities of enhanced biofilters were also elevated(p > 0.05), suggesting greater biodegradation potential. Operational parameters such as headloss development and turbidity control were not impaired by carbon supplementation strategies or an increase in biomass concentration and activity. However, the enhancement strategy did not provide improvement in terms of source water carbon removal(DOc and UV254) or DBP FP when treated filters were compared to a control.

关键词： Biological filtration carbon enhancement Biomass Disinfection by-products Dissolved organic carbon

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Inter-signal interaction and uncertain information in anuran multimodal signals

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current Zoology 2011年第2期57卷 153-161页

作者： Ryan c. taylor Barrett A. KLEIN Michael J. RYAN Department of Biological Sciences Salisbury University Salisbury MD 21801 USA Section of Integrative Biology University of Texas at Austin Austin TX 78712 USA Smithsonian Tropical Research Institute P.O. Box 0843-03092 Balboa Ancon Republic of Panama

Disentangling the influence of multiple signal components on receivers and elucidating general processes influencing complex signal evolution are difficult tasks. In this study we test mate preferences of female squirrel treefrogs Hyla squirella and female tungara frogs Physalaemus pustulosus for similar combinations of acoustic and visual components of their multimodal courtship signals. In a two-choice playback experiment with squirrel treefrogs, the visual stimulus of a male model significantly increased the attractivness of a relatively unattractive slow call rate. A previous study demonstrated that faster call rates are more attractive to female squirrel treefrogs, and all else being equal, models of male frogs with large body stripes are more attractive. In a similar experiment with female tungara frogs, the visual stimulus of a robotic frog failed to increase the attractiveness of a relatively unattractive call. Females also showed no preference for the distinct stripe on the robot that males commonly bear on their throat. Thus, features of conspicuous signal components such as body stripes are not universally important and signal function is likely to differ even among species with similar ecologies and communication systems. Finally, we discuss the putative information content of anuran signals and suggest that the categorization of redundant versus multiple messages may not be sufficient as a general explanation for the evolution of multimodal signaling. Instead of relying on untested assumptions concerning the information content of signals, we discuss the value of initially collecting comparative empirical data sets related to receiver responses.

关键词： Inter-signal interaction Multimodal signaling Signal detection Signal weighting Squirrel treefrog Hyla squirella Tfingara frog Physalaemus pustulosus Vocal sac

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Immunogenetic phenotypes in inflammatory bowel disease

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World Journal of Gastroenterology 2006年第23期12卷 3645-3650页

作者： Maria c Dubinsky Kent taylor Stephan R Targan Jerome I Rotter Departments of Pediatrics Medicine and Medical Genetics InstituteCedars-Sinai Medical CenterLos Angeles CAUnited States

The currently accepted etiopathogenic hypothesis suggests that the chronic intestinal inflammation and related systemic manifestations characteristic of inflammatory bowel disease （IBD） are due to an overly aggressive or pathologic immune response to resident luminal bacterial constituents. Predisposing factors are genetic dysregulation of mucosal immune responses and/ or barrier function, with onset triggered by environmental stimuli. These factors and their interactions may also be important determinants of disease phenotype and disease progression. The emergence of immunogenetic phenotypes lends support to the proposed hypothesis that susceptibility genes regulate distinct immune processes, driven by luminal antigens, expressed as specific immune phenotypes which in turn influence clinical phenotypes in IBD patient.

关键词： Inflammatory bowel disease Immunereactivity Disease phenotype

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Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

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Journal of Environmental Sciences 2009年第10期21卷 1336-1341页

作者： taylor Shauna M School of Environmental Science and Engineering Shanghai Jiao Tong University

Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium （NH4^＋-N）. In order to further understand its removal ability, several experiments were conducted to identify the growth and ammonium removal response at different carbon to nitrogen （c/N） mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions （c/N 10, 30℃, 120 r/min）, YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth, respectively. The nitrification products hydroxylamine （NHzOH）, nitrite （NO2^-） and nitrate （NO3^-） as well as the denitrification product, nitrogen gas （N2）, were detected under completely aerobic conditions.

关键词： Providencia rettgeri YL heterotrophic ammonium removal aerobic denitrification

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Experimental study of friction dissipators for seismic protection of building structures

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Earthquake Engineering and Engineering Vibration 2011年第4期10卷 475-486页

作者： F. López-Almansa S.T. de la cruz c. taylor Technical University of catalonia Architecture Structures Department Universidad Autónoma de ciudad Juárez Civil and Environmental Engineering Department civil Engineering Department University of Bristol

This paper presents the results from unidirectional shaking table tests of two reduced scale steel models of a building frame, with one and two floors, respectively. These frames incorporate friction dissipators at every floor. The inputs are sine-dwells and artificial and registered earthquakes. This study is part of a larger research project aiming to assess the seismic efficiency of friction dissipators by means of an integrated numerical and experimental approach. Inside this framework, the main objectives of these experiments are to：（i） collect a wide range of results to calibrate a numerical model derived within the project, （ii） clarify some of the most controversial issues about friction dissipators （including behavior for inputs containing pulses, capacity to reduce resonance peaks, introduction of high frequencies in the response, and self- generated eccentricities）, （iii） better understand their dynamic behavior, （iv） provide insight on the feasibility and reliability of using simple friction dissipators for seismic protection of building structures and （v） characterize the hysteretic behavior of these devices. Most of these objectives are satisfactorily reached and relevant conclusions are stated.

关键词： building structures earthquake engineering passive control friction energy dissipators experimentalverification shaking table tests

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Molecular genetics of ependymoma

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chinese Journal of cancer 2011年第10期30卷 669-681页

作者： Yuan Yao Stephen c. Mack Michael D. taylor Division of Neurosurgery Arthur and Sonia LabattBrain Tumour Research Centre Hospital for Sick Children TorontoOntario Canada Department of Laboratory Medicine and Pathobiology University of Toronto Toronto Ontario Canada.

Brain tumors are the leading cause of cancer death in children,with ependymoma being the third most common and posing a significant clinical *** mechanism of pathogenesis,reliable prognostic indicators,and effective treatments other than surgical resection have all remained *** recently,ependymoma research was hindered by the small number of tumors available for study,low resolution of cytogenetic techniques,and lack of cell lines and animal *** heterogeneity,which manifests as variations in tumor location,patient age,histological grade,and clinical behavior,together with the observation of a balanced genomic profile in up to 50% of cases,presents additional challenges in understanding the development and progression of this *** these difficulties,we have made significant headway in the past decade in identifying the genetic alterations and pathways involved in ependymoma tumorigenesis through collaborative efforts and the application of microarray-based genetic(copy number) and transcriptome profiling *** characterization of ependymoma unraveled distinct mRNA-defined subclasses and led to the identification of radial glial cells as its cell type of *** review summarizes our current knowledge in the molecular genetics of ependymoma and proposes future research directions necessary to further advance this field.

关键词：分子遗传学室管膜肿瘤发生发病机制手术切除动物模型遗传变异遗传特性

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Synthesis of a-SnWO_4 thin-film electrodes by hydrothermal conversion from crystalline WO_3

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chinese chemical Letters 2015年第4期26卷 474-478页

作者： Kayla J.Pyper taylor c.Evans Bart M.Bartlett Department of chemistry University of Michigan

Thin film electrodes of the orthorhombic form of tin tungstate （α-SnWO4） were prepared using a hydrothermal method to convert thin films of WO3 in aqueous SncI2. The pH dependence of the growth mechanism was identified by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The XRD patterns show complete conversion of WO3（s） to SnWO4（s） at pH 1, 4, and 7. SEM images reveal a morphology change from sponge-like platelets to sharp nanowires as the pH increases from 1 to 7. The α-SnWO4 thin films were reddish brown in color, and display an indirect band gap of 1.9 eV by diffuse reflectance UV-vis spectroscopy. α-SnWO4 is therefore solar-responsive, and a chopped light linear sweep voltammogram recorded under 100 mW/cm2 AM1.5 simulated solar illumination in a pH 5 0.1 mol/L KPi buffer show a visible light response for photoelectrochemical water oxidation, producing 32 μA/cm2 at 1.23 V vs. RHE.

关键词： Alpha tin tungstateHydrothermal conversionMicrostructureHydrothermal method

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In situ selective laser gas nitriding for composite TiN/Ti-6Al-4V fabrication via laser powder bed fusion

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Journal of Materials Science & Technology 2020年第10期42卷 98-107页

作者： P.A.Morton H.c.taylor L.E.Murr O.G.Delgado c.A.Terrazas R.B.Wicker W.M.Keck center for 3D Innovation The University of Texas at El PasoEl PasoTX79968USA Department of Mechanical Engineering The University of Texas at El PasoTX 79968USA Department of Metallurgical Materials and Biomedical EngineeringThe University of Texas at El PasoTX 79968USA

Laser-assisted gas nitriding of selective Ti-6Al-4V surfaces has been achieved during laser powder bed fusion fabrication by exchanging the argon build gas environment with *** variation of processing parameters allowed microdendritic Ti N surface coatings to be formed having thicknesses ranging from a few tens of microns to several hundred microns,with TiN dendrite microstructure volume fractions ranging from 0.6 to 0.75;and corresponding Vickers microindentation hardness values ranging from^7.5 GPa–9.5 *** TiN hard layers ranging from 50μm to 150μm thick were also fabricated in the laser-beam additively manufactured Ti-6Al-4V alloy producing prototype,hybrid,planar composites having alternating,ductile Ti-6Al-4V layers with a hardness of^4.5 GPa and a stiff,TiN layer with a hardness of^8.5 *** results demonstrate prospects for fabricating novel,additively manufactured components having selective,hard,wear and corrosion resistant coatings along with periodic,planar or complex metal matrix composite regimes exhibiting superior toughness and related mechanical properties.

关键词： Ti-6Al-4V TiN ceramic coatings and embedded layers Dendritic microstructures Selective laser melting Additive manufacturing Metal matrix composites Selective nitriding

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Behavioral and neural auditory thresholds in a frog

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current Zoology 2019年第3期65卷 333-341页

作者： Ryan c.taylor Karin AKRE Walter WILcZYNSKI Michael J.RYAN Department of Integrative Biology University of Texas at Austin Austin TX USA Department of Biological Sciences Salisbury University Salisbury MD USA Smithsonian Tropical Research Institute Balboa Republic of Panama Neuroscience Institute and center for Behavioral Neuroscience Georgia State University Atlanta GA USA

Vocalizations play a critical role in mate recognition and mate choice in a number of taxa, especially, but not limited to, orthopterans, frogs, and birds. But receivers can only recognize and prefer sounds that they can hear. Thus a fundamental question linking neurobiology and sexual selection asks-what is the threshold for detecting acoustic sexual displays? In this study, we use 3 methods to assess such thresholds in tdngara frogs: behavioral responses, auditory brainstem responsesz and multi unit electrophysiological recordi ngs from the *** show that thresholds are lowest for multiunit recordings (ca. 45 dB SPL), and then for behavioral responses (ca. 61 dB SPL), with auditory brainstem responses exhibiting the highest thresholds (ca. 71 dB SPL). We discuss why these estimates differ and why, as with other studies, it is unlikely that they should be the same. Although all of these studies estimate thresholds they are not measuring the same thresholds;behavioral thresholds are based on signal salienee whereas the 2 neural assays estimate physiological thresholds. All 3 estimates, however, make it clear that to have an appreciation for detection and salienee of acoustic signals we must listen to those signals through the ears of the receivers.

关键词： anurans auditory brainstem responses auditory thresholds mate choice Physalaemus pustulosus signal recog nition thresholds sexual selection tungara frogs vocalizations

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