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Men with a complete absence of normal sperm morphology exhibit high rates of success without assisted reproduction

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Asian Journal of Andrology 2017年第1期19卷 39-42页

作者： Jason R Kovac ryan p.smith Miguel Cajipe Dolores J Lamb Larry I Lipshultz Center of Reproductive Medicine and the Department of Molecular and Cellular Biology Scott Department of Urology Baylor College of Medicine Houston TX USA Department of Urology University of Virginia Charlottesville VA USA.

In couples with infertility, abnormal strict morphology of 0% normal forms （NF） is a criterion to proceed rapidly to in vitro fertilization （IVF）. Since no data currently exist, we investigated the outcomes for men with 0% NF to determine reproductive success without the use of assisted reproductive technologies （ART）. A cohort of 24 men with 0% NF were identified （2010-2013） with 27 randomly selected men with 〉4% NF as controls. patient charts were reviewed with men contacted and administered an Institutional Review Board （IRB）-approved telephone questionnaire to ascertain outcomes. After a median follow-up time of 2.5 years, 29.2% of men with 0% NF did not require ART for their first pregnancy （controls = 55.6%, p〈 0.05）. When all pregnancies were analyzed together, men with 0% NF achieved twenty pregnancies of which 75% did not require IVF （controls - thirty pregnancies; 76.7% did not require IVF）. The average age of men and female partners was similar between men with 0% NF and 〉4% NF. All men had normal follicle-stimulating hormone （FSH）, testosterone, prolactin, sex hormone-binding globulin （SHBG）, and estradiol. Although, global semen parameters were worse in men with 0% NF, when a first pregnancy was a natural conception （NC）, 100% of men with 0% NF （n = 7/7） and 37.5% of controls in = 3/8） went on to have a subsequent pregnancy via NC. Men with 0% NF conceived without IVF in 29.2% of cases compared to 55.6% of controls. Strict morphology should not be used to predict fertilization, pregnancy, or live birth potential. In men with 0% NF, alternative modalities should be considered before immediate IVF.

关键词： conception infertility intrauterine insemination in vitro fertilization strict morphology success

The effects of advanced paternal age on fertility

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Asian Journal of Andrology 2013年第6期15卷 723-728,I0005页

作者： Jason R Kovac Josephine Addai ryan p.smith Robert M Coward Dolores J Lamb Larry I Lipshultz Scott Department of Urology Department of Molecular and Cellular Biology The Center for Reproductive Medicine Baylor College of Medicine Houston TX 77030 USA

Modern societal pressures and expectations over the past several decades have resulted in the tendency for couples to delay conception. While women experience a notable decrease in oocyte production in their late thirties, the effect of age on spermatogenesis is less well described. While there are no known limits to the age at which men can father children, the effects of advanced paternal age are incompletely understood. This review summarizes the current state of knowledge regarding advanced paternal age and its implications on semen quality, reproductive success and offspring health. This review will serve as a guide to physicians in counseling men about the decision to delay paternity and the risks involved with conception later in life.

关键词： aging male fertility outcomes male infertility paternal age

Direct-to-indirect mapping for optimal low-thrust trajectories

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Astrodynamics 2024年第1期8卷 27-46页

作者： David Ottesen ryan p.Russell Department of Aerospace Engineering and Engineering Mechanics The University of Texas at AustinAustinTexas78712USA

Optimal,many-revolution spacecraft trajectories are challenging to solve.A connection is made for a class of models between optimal direct and indirect *** transfers that minimize thrust-acceleration-squared,primer vector theory maps direct,many-impulsive-maneuver trajectories to the indirect,continuous-thrust-acceleration *** mapping algorithm is independent of how the direct solution is obtained and requires only a solver for a boundary value problem and its partial derivatives.A Lambert solver is used for the two-body problem in this *** mapping is simple because the impulsive maneuvers and co-states share the same linear space around an optimal *** numerical results,the direct coast-impulse solutions are demonstrated to converge to the indirect continuous solutions as the number of impulses and segments *** two-body design space is explored with a set of three many-revolution,many-segment examples changing semimajor axis,eccentricity,and *** first two examples involve a small change to either semimajor axis or eccentricity,and the third example is a transfer to geosynchronous *** a single processor,the optimization runtime is seconds to minutes for revolution counts of 10 to 100,and on the order of one hour for examples with up to 500 *** of these thrust-acceleration-squared solutions are good candidates to start a homotopy to a higher-fidelity minimization problem with practical constraints.

关键词： direct optimization indirect optimization impulsive maneuvers Lambert's problem two-body dynamics primer vectortheory

Survey of unmanned subterranean exploration,navigation,and localisation

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IET Cyber-Systems and Robotics 2020年第1期2卷 1-13页

作者： Jeffrey Martz Wesam Al-Sabban ryan N.smith physics and Engineering Fort Lewis CollegeDurangoCOUSA Computer and Information Systems umm Al Qura UniversityMakkahSaudi Arabia

Subsurface networks include mining tunnels,caves,and the urban *** of these environments presents a complex setting with significant challenges in exploration,exploitation,*** hazards exist,including environmental and structural,and conditions degrade and change *** present a survey of research in autonomy,networking and mobility focused on exploring and/or mapping subsurface networks in unpredictable and unexplored *** focus is on mining tunnels as a proxy subterranean environment;motivated by the proximity of the authors to the Bonita peak Mining District;a Superfund site consisting of 48 historic mines which have contaminated soil,groundwater and surface water with heavy metals as a result of historic *** exploration and assessment of the mining tunnels for remediation efforts presents an extremely challenging problem in subterranean ***,the environment in question is the most extreme and challenging subterranean *** assets must enter to explore and re-map the tunnels to assess safety for subsequent entrance by robots and/or humans for proper *** survey is split into three categories--Locomotion,GpS-denied navigation and localization,and *** is concluded with a proposed design for a platform that addresses the difficulties of exploring an abandoned mine.

关键词： groundwater underground exploration

Nexus between polymer support and metal oxide nanoparticles in hybrid nanosorbent materials （HNMs） for sorption/desorption of target ligands

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Frontiers of Environmental Science & Engineering 2015年第5期9卷 929-938页

作者： ryan C. smith Jinze LI Surapol pADUNGTHON Arup K. SENGUpTA Environmental Engineering program Department of Civil and Environmental Engineering Lehigh University Bethlehem PA 18015 USA

Metal oxide nanoparticles like hydrated ferric oxide （HFO） or hydrated zirconium oxide （HZrO） are excellent sorbents for environmentally significant ligands like phosphate, arsenic, or fluoride, present at trace concentrations. Since the sorption capacity is surface dependent for HFO and HZrO, nanoscale sizes offer significant enhancement in performance. However, due to their miniscule sizes, low attrition resistance, and poor durability they are unable to be used in typical plug-flow column setups. Meanwhile ion exchange resins, which have no specific affinity toward anionic ligands, are durable and chemically stable. By impregnating metal oxide nanoparticles inside a polymer support, with or without functional groups, a hybrid nanosorbent material （HNM） can be prepared. A HNM is durable, mechanically strong, and chemically stable. The functional groups of the polymeric support will affect the overall removal effi- ciency of the ligands exerted by the Donnan Membrane Effect. For example, the removal of arsenic by HFO or the removal of fluoride by HZrO is enhanced by using anion exchange resins. The HNM can be precisely tuned to remove one type of contaminant over another type. Also, the physical morphology of the support material, spherical bead versus ion exchange fiber, has a significant effect on kinetics of sorption and desorption. HNMs also possess dual sorption sites and are capable of removing multiple contaminants, namely, arsenate and perchlorate, concurrently.

关键词： ion exchange sorpfion arsenic perchlorat~,fluoride

Are we leveling the playing field？ Trends and disparities in sports participation among sexual minority youth in Canada

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Journal of Sport and Health Science 2018年第2期7卷 218-226页

作者： Marion Doull ryan J.Watson Annie smith Yuko Homma Elizabeth Saewyc Stigma and Resilience Among Vulnerable Youth Centre School of Nursing University of British Columbia Vancouver British Columbia V6T2B5 Canada Department of Human Development and Family Studies University of Connecticut Storrs CT 06269 USA McCreary Centre Society Vancouver British Columbia V5K2A 7 Canada School of Nursing Mukogawa Women's University Nishinomiya Hyogo 663-8558 Japan

purpose: Sports participation and physical fitness are widely beneficial for young people, yet activity levels among young people are *** growing popular media attention on the participation of sexual minority(e.g., lesbian, gay, and bisexual) youth in sports and various campaigns to improve the often homophobic climate of sports, there is limited evidence that sexual minority youth participate in sports. Our aim was to provide a current portrait of sports participation among 3 groups of sexual minority youth(e.g., lesbian, gay, and bisexual) in British Columbia, Canada, as well as to document population ***: pooled population-level data from British Columbia, Canada(n = 99,373) were used to examine trends and disparities in sports participation among sexual minority and heterosexual youth. Age-adjusted logistic regression models were used to examine changes in participation over time and disparities in participation over time(1998—2013).Results: We found an overall decline in sports participation and physical activity(pA) for all youth. Sexual minority students were less likely to participate in formal sports(with a coach) and informal sports(without a coach) compared with their heterosexual peers. The disparity in participating in informal sports between heterosexual and sexual minority youth has narrowed over time for some sexual orientation groups, whereas the disparity in participating in formal sports has widened over time in some ***: This study provides a comprehensive examination of sports participation among sexual minority youth over the past 15 *** changing societal attitudes and laudable efforts to reduce homophobia in sports, results suggest that there are continued barriers to participation for sexual minority youth. Further research is needed to understand the factors that limit sports participation for these youth and to inform program development. pA is critical to lifelong health and well-being, and

关键词： Canada Disparities physical activity Sexual minority youth Sexual orientation Sports participation

Demonstration of tantalum as a structural material for MEMS thermal actuators

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Microsystems & Nanoengineering 2021年第1期7卷 85-97页

作者： Longchang Ni ryan M.pocratsky Maarten p.de Boer CMU Mechanical Engineering Dept. 5000 Forbes Ave.PittsburghPA 15213USA present address:Fischione Instruments 9003 Corporate CirExportPA 15632USA

This work demonstrates the processing,modeling,and characterization of nanocrystalline refractory metal tantalum(Ta)as a new structural material for microelectromechanical system(MEMS)thermal actuators(TAs).Nanocrystalline Ta films have a coefficient of thermal expansion(CTE)and Young’s modulus comparable to bulk Ta but an approximately ten times greater yield *** mechanical properties and grain size remain stable after annealing at temperatures as high as 1000°*** has a high melting temperature(Tm=3017℃)and a low resistivity(ρ=20µΩcm).Compared to TAs made from the dominant MEMS material,polycrystalline silicon(polysilicon,Tm=1414℃,ρ=2000µΩcm),Ta TAs theoretically require less than half the power input for the same force and displacement,and their temperature change is half that of *** TAs operate at a voltage 16 times lower than that of other TAs,making them compatible with complementary metal oxide semiconductors(CMOS).We selectα-phase Ta and etch 2.5-μm-thick sputterdeposited films with a 1μm width while maintaining a vertical sidewall profile to ensure in-plane movement of TA *** is 25 times thicker than the thickest reactive-ion-etchedα-Ta reported in the technical *** stress sensitivities to sputter parameters and to hydrogen incorporation are investigated and ***,a V-shaped TA is fabricated and tested in *** conventional actuation by Joule heating and passive self-actuation are as predicted by models.

关键词： thermal structural thick

Future directions for screening and treatment in congenital hearing loss

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precision Clinical Medicine 2020年第3期3卷 175-186页

作者： ryan K.Thorpe Richard J.H.smith Molecular Otolaryngology and Renal Research Laboratories Carver College of MedicineUniversity of Iowa375 Newton RdIowa CityIA 52242USA Department of Otolaryngology–Head and Neck Surgery University of Iowa200 Hawkins DrIowa CityIA 52242USA The Interdisciplinary Graduate program in Genetics University of Iowa375 Newton RdIowa CityIA 52242USA Iowa Institute of Human Genetics University of Iowa375 Newton RdIowa CityIA 52242USA

Hearing loss is the most common neurosensory *** results froma variety of heritable and acquired causes and is linked to multiple deleterious effects on a child’s development that can be ameliorated by prompt identification and individualized *** hearing loss in newborns is challenging,especially in mild or progressive cases,and its management requires a multidisciplinary team of healthcare providers comprising audiologists,pediatricians,otolaryngologists,and genetic *** physiologic newborn hearing screening has resulted in earlier diagnosis of hearing loss than ever before,a growing body of knowledge supports the concurrent implementation of genetic and cytomegalovirus testing to offset the limitations inherent to a singular screening *** this review,we discuss the contemporary role of screening for hearing loss in newborns as well as future directions in its diagnosis and treatment.

关键词： genetic hearing loss deafness cytomegalovirus newborn screening precision medicine

Investigation of a cyanine dye assay for the evaluation of the biocompatibility of magnesium alloys by direct and indirect methods

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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