183 research outputs found

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    Risk of Complications After Hydrocele Surgery : A Retrospective Multicenter Study in Helsinki Metropolitan Area

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    Publisher Copyright: © 2022 The AuthorsBackground: Despite being one of the most frequent urological procedures, the risk estimates for complications after hydrocele surgery (hydrocelectomy) are uncertain. Decision-making about hydrocelectomy involves balancing the risk of complications with efficacy of surgery—a tradeoff that critically depends on the complication risks of hydrocele surgery. Objective: To examine the 90-d risks of complications of hydrocele surgery in a large, contemporary sample. Design, setting, and participants: We retrospectively reviewed all surgeries performed for nonrecurrent hydroceles conducted in all five Helsinki metropolitan area public hospitals from the beginning of 2010 till the end of 2018, and evaluated the complication outcomes. Outcome measurements and statistical analysis: The following outcomes were evaluated: (1) risk of moderate or severe (Clavien-Dindo II–V) hydrocele surgery complications, (2) risk of reoperation due to a surgical complication, and (3) risk of an unplanned postoperative visit to the emergency room or outpatient clinic, all within 90 d after surgery. Results and limitations: We identified 866 hydrocele operations (38 [4.3%] bilateral operations). A total of 139 (16.1%) patients had moderate or severe hydrocele surgery complications within 90 d after surgery. Of the 139 complications, 94 were (10.9% of all or 67.6% of patients with moderate or severe complications) Clavien-Dindo grade II, 43 (5.0% and 30.9%, respectively) grade III, two (0.2% and 1.4%, respectively) grade IV, and none grade V. A total of 45 patients (5.2% of all and 32.4% of those who had moderate or severe complications) required immediate reoperation due to complications. All together 219 operated patients (25.3% of all operated patients) had an unplanned visit to the emergency room. The retrospective study design limits the reliability of the results. Conclusions: Complications after hydrocele surgery are common and warrant further research. These estimates can be useful in shared decision-making between clinicians and patients. Patient summary: We investigated the complication rates after hydrocele surgery and found that complications are common after a procedure often considered minor: every ninth patient had a moderate and every 20th a severe complication. Every fourth patient had an unplanned postoperative visit to the emergency room.Peer reviewe

    Operation of TUT Solar PV Power Station Research Plant under Partial Shading Caused by Snow and Buildings

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    A grid connected solar photovoltaic (PV) research facility equipped with comprehensive climatic and electric measuring systems has been designed and built in the Department of Electrical Engineering of the Tampere University of Technology (TUT). The climatic measuring system is composed of an accurate weather station, solar radiation measurements, and a mesh of irradiance and PV module temperature measurements located throughout the solar PV facility. Furthermore, electrical measurements can be taken from single PV modules and strings of modules synchronized with the climatic data. All measured parameters are sampled continuously at 10 Hz with a data-acquisition system based on swappable I/O card technology and stored in a database for later analysis. The used sampling frequency was defined by thorough analyses of the PV system time dependence. Climatic and electrical measurements of the first operation year of the research facility are analyzed in this paper. Moreover, operation of PV systems under partial shading conditions caused by snow and building structures is studied by means of the measured current and power characteristics of PV modules and strings

    Cascade transformations of (±)-citronellal to menthol over extruded Ru-MCM-41 catalysts in a continuous reactor

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    Cascade transformations of (±)-citronellal in a continuous mode were investigated over a bifunctional shaped ruthenium catalyst bearing metal clusters of the size 7–13 nm. Four types of Ru/H-MCM-41 extrudates (1.5 × 10 mm) containing 30% of Bindzil-50/80 colloidal silica binder were prepared varying in metal location and metal-to-acid ratio, while the concentration of BrĂžnsted and Lewis acid sites and textural properties of the final extrudates were comparable. Catalytic tests were performed in the trickle-bed reactor under 70 °C, 10 bar of H2, and the initial reactant concentration in cyclohexane 0.086 mol L−1 for the liquid residence time of 12.5 min. As a reactant, isopulegol, citronellol or (±)-citronellal was used. Metal location in extrudates has a significant effect on the catalytic activity and selectivity especially in terms of isopulegol isomers which content correlated with the metal-to-acid site ratio. Stereoselectivity to the desired (±)-menthol was 68–70%. The highest amount of the desired menthol, 32% yield, was obtained over extrudates where Ru was deposited on the catalytic support, i.e. with the shortest distance between the acid and metal sites, the lowest BrĂžnsted acidity, the lowest BrĂžnsted–Lewis acid sites ratio, the highest specific surface area and the narrowest range of the Ru particle size distribution.</p

    Transformations of citral over bifunctional Ru-H-Y-80 extrudates in a continuous reactor

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    One-pot transformations of citral were investigated over Ru-catalysts in a batch and a continuous mode over a powder catalyst and extrudates, respectively. Ru/H-Y-80 catalysts were prepared by different impregnation methods to obtain different particle sizes of Ru.The highest yield of isopulegols was 15% and yield of menthols was 3% with stereoselectivity to the desired (±)-menthol isomer of 42% after 5 h over the Ru/H-Y-80 powder catalyst with the smallest metal particles prepared by the incipient wetness impregnation method with six impregnation steps using Ru(NO)(NO3)3 as a precursor. This catalyst was synthesized with the Bindzil binder and shaped by extrusion.For comparison, also a catalyst with Ru deposited on the binder was prepared. Addition of 30 wt% Bindzil binder to Ru/H-Y-80 catalyst caused significant catalyst deactivation. Z/E-citral ratio decreased with increasing Ru particle size. Citral conversion and the yield of acyclic hydrogenation products were higher over the powder catalysts containing a mixture of zeolite and binder with a larger distance between the metal and the acid sites, i.e. with Ru deposited on the Bindzil binder. Long-term experiments in the continuous mode revealed comparable catalytic behaviour of both Ru-extrudates with the controlled metal location due to the presence of diffusion regime. The maximum yield of menthols, 6%, with stereoselectivity to the desired (±)-menthol of 73% was obtained during the transient state, below 2 h of time-on-stream. The reuse of Ru/H-Y-80 extrudates was successfully demonstrated.</p
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