138 research outputs found

    Systematics of Unionicola Laurentiana, N.Sp., and U. Nearctica, N. Sp., Sponge-Associated Hydracarina (Parasitengona: Unionicolidae) from North America

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    Author Institution: Department of Biology, Saint Lawrence University; Zoologisch Laboratorium, Universiteit van Amsterdam, The NetherlandsThe sponge-associated Hydracarina of North America historically have been considered conspecific with the European species Unionicola crassipes (Miiller 1776). Ratio diagrams based on numerous morphological characteristics distinguish the North American crassipes-like mites from U. crassipes and two North American species are described. Unionicola laurentiana, n.sp., occurs in the Laurentian Great Lakes and St. Lawrence River basins. U. nearctica, n.sp., occurs in that region and its range extends across Canada from Ontario to British Columbia

    Undergoing varicocele repair before assisted reproduction improves pregnancy rate and live birth rate in azoospermic and oligospermic men with a varicocele: a systematic review and meta-analysis

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    OBJECTIVE: To evaluate how varicocele repair (VR) impacts pregnancy (PRs) and live birth rates in infertile couples undergoing assisted reproduction wherein the male partner has oligospermia or azoospermia and a history of varicocele. DESIGN: Systematic review and meta-analysis. SETTING: Not applicable. PATIENT(S): Azoospermic and oligospermic males with varicoceles and in couples undergoing assisted reproductive technology (ART) with IUI, IVF, or testicular sperm extraction (TESE) with IVF and intracytoplasmic sperm injection (ICSI). INTERVENTION(S): Measurement of PRs, live birth, and sperm extraction rates. MAIN OUTCOME MEASURE(S): Odds ratios for the impact of VR on PRs, live birth, and sperm extraction rates for couples undergoing ART. RESULT(S): Seven articles involving a total of 1,241 patients were included. Meta-analysis showed that VR improved live birth rates for the oligospermic (odds ratio [OR] = 1.699) and combined oligospermic/azoospermic groups (OR = 1.761). Pregnancy rates were higher in the azoospermic group (OR = 2.336) and combined oligospermic/azoospermic groups (OR = 1.760). Live birth rates were higher for patients undergoing IUI after VR (OR = 8.360). Sperm retrieval rates were higher in persistently azoospermic men after VR (OR = 2.509). CONCLUSION(S): Oligospermic and azoospermic patients with clinical varicocele who undergo VR experience improved live birth rates and PRs with IVF or IVF/ICSI. For persistently azoospermic men after VR requiring TESE for IVF/ICSI, VR improves sperm retrieval rates. Therefore, VR should be considered to have substantial benefits for couples with a clinical varicocele even if oligospermia or azoospermia persists after repair and ART is required

    Ultrafast Dynamics for Electron Photodetachment from Aqueous Hydroxide

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    Charge-transfer-to-solvent (CTTS) reactions of hydroxide induced by 200 nm monophotonic or 337 nm and 389 nm biphotonic excitation of this anion in aqueous solution have been studied by means of pump-probe ultrafast laser spectroscopy. Transient absorption kinetics of the hydrated electron, eaq-, have been observed, from a few hundred femtoseconds out to 600 ps, and studied as function of hydroxide concentration and temperature. The geminate decay kinetics are bimodal, with a fast exponential component (ca. 13 ps) and a slower power "tail" due to the diffusional escape of the electrons. For the biphotonic excitation, the extrapolated fraction of escaped electrons is 1.8 times higher than for the monophotonic 200 nm excitation (31% vs. 17.5% at 25 oC, respectively), due to the broadening of the electron distribution. The biphotonic electron detachment is very inefficient; the corresponding absorption coefficient at 400 nm is < 4 cm TW-1 M-1 (assuming unity quantum efficiency for the photodetachment). For [OH-] between 10 mM and 10 M, almost no concentration dependence of the time profiles of solvated electron kinetics was observed. At higher temperature, the escape fraction of the electrons increases with a slope of 3x10-3 K-1 and the recombination and diffusion-controlled dissociation of the close pairs become faster. Activation energies of 8.3 and 22.3 kJ/mol for these two processes were obtained. The semianalytical theory of Shushin for diffusion controlled reactions in the central force field was used to model the geminate dynamics. The implications of these results for photoionization of water are discussed.Comment: 44 pages, 9 figures; supplement: 4 pages, 7 figures; to be submitted to J. Chem. Phy

    Excitation-energy dependence of the mechanism for two-photon ionization of liquid H2O and D2O from 8.3to12.4eV

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    This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/125/4/10.1063/1.2217738.Transient absorption measurements monitor the geminate recombination kinetics of solvated electrons following two-photonionization of liquid water at several excitation energies in the range from 8.3to12.4eV. Modeling the kinetics of the electron reveals its average ejection length from the hydronium ion and hydroxyl radical counterparts and thus provides insight into the ionization mechanism. The electron ejection length increases monotonically from roughly 0.9nm at 8.3eV to nearly 4nm at 12.4eV, with the increase taking place most rapidly above 9.5eV. We connect our results with recent advances in the understanding of the electronic structure of liquid water and discuss the nature of the ionization mechanism as a function of excitation energy. The isotope dependence of the electron ejection length provides additional information about the ionization mechanism. The electron ejection length has a similar energy dependence for two-photonionization of liquid D(2)O, but is consistently shorter than in H(2)O by about 0.3nm across the wide range of excitation energies studied

    On the Air and Online! Librarians and Doctors Using a Blog and Radio Show to Communicate with Listeners About Health

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    Objective: Health Sciences librarians partner with producers of a weekly health-oriented radio show hosted by clinicians. Librarians helped develop the show?s interactive website/blog, provide weekly content links, and continue to help improve website functionality as the show expands in scope. They help the show?s staff find and use images appropriately and analyze statistics to understand user behavior on the blog/website. Methods: The show is hosted by Family Medicine clinicians in the School of Medicine at a major southeastern state university and airs on local AM radio. The university?s health sciences librarians provide assistance with the website/blog and supplement radio content with website links to reputable consumer health websites. The show?s website was developed as a WordPress.com blog, which interoperates with the show?s other social media. Audio podcasts are available via iTunes. Librarians selected MedlinePlus terms for indexing of medical topics and are exploring supplemental indexing for non-medical topics. Librarians use WordPress?s Site Statistics to analyze blog/website use. Challenges include communicating with everyone involved, improving blog/website functionality as it and the show expand in scope, helping the show?s staff understand and implement appropriate use of images on the website, and scheduling librarian coverage of shows. Results/Outcome: The library is listed as a sponsor on the show?s website and is acknowledged on-air weekly. Hosts mention librarian assistance when directing listeners to the website for more information. Website statistics reveal that the blog has been visited more than 10,000 times in just over a year. The library link on the website/blog sidebar is among the most frequently visited links. This partnership increases the public?s access to quality health information via the radio and blog. Feedback from the show?s producer and hosts has been favorable and the partnership continues. The show anticipates syndicating and expanding across the state. Discussion/Conclusion: Both the library and the radio show have gained from this unique partnership. Through this project, librarians have obtained valuable practical experience that helps them in their work with other users. They have augmented online resources for finding and appropriately using images and have received library support to explore the more flexible WordPress.org platform for this and other projects. In collaboration with clinicians they are bringing better health information to the public. The librarians have made valuable contributions in areas including social media, design, knowledge and provision of consumer health resources, and health information literacy. Subject (LCSH): Academic libraries -- Relations with faculty and curriculu

    Determining Risk Factors That affect Progression in Patients With Nonproliferative Diabetic Retinopathy

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    PURPOSE: to determine risk factors that affect nonproliferative diabetic retinopathy (NPDR) progression and establish a predictive model to estimate the probability of and time to progression in NPDR. RESULTS: Two hundred thirty patients were included. Initially, 65 eyes (28.3%) had no retinopathy; 73 (31.7%) mild NPDR; 60 (26.1%) moderate NPDR; and 32 (13.9%) severe NPDR. Patients were followed for a mean of 5.8 years (±2.0 years; range 2.1-9.4 years). 164 (71.3%) eyes progressed during the follow-up. Time-independent risk factors affecting progression rate were age (hazard ratio (HR) = 0.99, CONCLUSION: HbA1c level is a significant modifiable risk factor in controlling the progression of DR. The proposed model could be used to predict the time and rate of progression based on an individual\u27s risk factors. A prospective multicenter study should be conducted to further validate our model

    Electron Photodetachment from Aqueous Anions. II. Ionic Strength Effect on Geminate Recombination Dynamics and Quantum Yield for Hydrated Electron

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    In concentrated solutions of NaClO4 and Na2SO4, the quantum yield for free electron generated by detachment from photoexcited anions (such as I-, OH-, ClO^4-, and [SO3]^2-) linearly decreases by 6-12% per 1 M ionic strength. In 9 M sodium perchlorate solution, this quantum yield decreases by roughly an order of magnitude. Ultrafast kinetic studies of 200 nm photon induced electron detachment from Br-, HO- and [SO3]^2- suggest that the prompt yield of thermalized electron does not change in these solutions; rather, the ionic strength effect originates in more efficient recombination of geminate pairs. Within the framework of the recently proposed mean force potential (MFP) model of charge separation dynamics in such photosystems, the observed changes are interpreted as an increase in the short-range attractive potential between the geminate partners. Association of sodium cation(s) with the electron and the parent anion is suggested as the most likely cause for the observed modification of the MFP. Electron thermalization kinetics suggest that the cation associated with the parent anion (by ion pairing and/or ionic atmosphere interaction) is passed to the detached electron in the course of the photoreaction. The precise atomic-level mechanism for the ionic strength effect is presently unclear; any further advance is likely to require the development of an adequate quantum molecular dynamics model.Comment: 40 pages, 10 figures + supplement 2 pages, 9 figures; will be submitted, in a modified form, to J. Phys. Chem

    Recombination of Geminate (OH,eaq-) Pairs in Concentrated Alkaline Solutions: Lack of Evidence For Hydroxyl Radical Deprotonation

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    Picosecond dynamics of hydrated electrons and hydroxyl radicals generated in 200 nm photodissociation of aqueous hydroxide and 400 nm (3-photon) ionization of water in concentrated alkaline solutions were obtained. No deprotonation of hydroxyl radicals was observed on sub-nanosecond time scale, even in 1-10 M KOH solutions. This result is completely at odds with the kinetic data for deprotonation of OH radical in dilute alkaline solutions. We suggest that the deprotonation of hydroxyl radical is slowed down dramatically in concentrated alkaline solutions.Comment: 12 pages; 2 figures; submitted to Chem. Phys. Let

    Postoperative Complications of True Dropless Cataract Surgery versus Standard Topical Drops

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    Purpose  Compare postoperative outcomes in cataract surgery between eyes with standard drop regimen versus dropless protocol by residents. Design  Retrospective cohort study between April 1, 2018 and March 31, 2020. Methods  The study was performed at Lyndon B. Johnson General Hospital in Houston, Harris County, Texas. A total of 547 eyes (234 dropless vs. 313 standard) with phacoemulsification cataract surgery and minimum of 1-month follow-up with best-corrected visual acuity (BCVA) were included. Dropless received 40 mg sub-Tenon\u27s triamcinolone and intracameral moxifloxacin. Patients were followed at postoperative day 1 (POD1), week 1 (POW1), and month 1 (POM1). Postoperative rate of BCVA better than 20/40 (Good vision) and rate of complications were compared between groups. Results  Good vision on POM1 in dropless (77.8%) was noninferior to standard (75.1%, p  = 0.80). Complication rate in dropless (28.6%) was noninferior to standard (24.0%, p  = 0.13). Intraocular pressure (IOP) elevation on POD1 ( p  = 0.041) and anterior chamber (AC) cells on POW1 and POM1 ( p  \u3c 0.001) were more frequent in dropless. Mean spherical equivalent at POM1 was better in dropless (−0.37 D [±0.81 D]) compared with standard (−0.61D [±0.77 D], p  = 0.001). Early posterior capsular opacification (early PCO) was more frequent in dropless ( p  = 0.042). Conclusions  Postoperative rate of BCVA better than 20/40 and rate of postoperative complications were noninferior, although dropless had higher rates of AC inflammation, IOP elevation, and early PCO

    Microneurosurgical Anastomoses for Cerebral Ischemia [Contents]

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    From jacket: The purpose of this volume is to present a series of important papers on the rapidly growing surgical field of microneurosurgical anastomoses for cerebral ischemia. It includes papers on the indications and results of microneurosurgical bypass anastomoses; on the techniques used to study patients before and after surgery, including cerebral blood flow psychometic testing, etc.; and on the basic mechanisms of cerebral ischemia studies in animals. New ideas are suggested for techniques involving increased use of the occipital arteries and the development of vein, arterial, or prosthetic grafts in place of the STA (superficial temporal artery). Also discussed are the importance of measuring blood flow in the STA where possible, and the measurement of cerebral blood flow pre- and postoperatively to monitor the results. Psychometric studies are shown to be of importance pre- and postoperatively in addition to careful neurologic evaluation
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