360 research outputs found

    Dual stimulation protocol for poor responders, promising approach to increase the success rate of in vitro fertilization cycles

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    Background: It is well known that increasing the number of recruited oocytes affect positively the in vitro fertilization (IVF) cycle outcome. Dual stimulation protocol was invented to increase the number of recruited oocytes in the same cycle through double stimulation and oocyte collection.Methods: This prospective randomized controlled study was done to compare the outcome of one conventional aspiration-embryo transfer cycle with double stimulation- aspiration then frozen transfer cycle. The results were divided into primary outcomes which included the number of oocytes collected, the maturation rate in both times of oocyte collection and in both groups and while the secondary outcome included the oocytes survival rate, fertilization rate, cleavage rate, available blastocyst, and finally pregnancy rate in both arms of the study.Results: A total of 180 patients included. In the first group: 203 oocytes were collected with 151 mature oocytes (maturation rate 74%, fertilization rate of 81.5%), 61 good quality embryos and transferred in 27 cycles (49.6% transfer rate) and 4 got pregnant (14.8% pregnancy rate). In the second group: we got 381 oocytes in total through twice oocyte collection, with 289 mature oocytes (75.8% maturation rate). The second group underwent frozen oocytes transfer cycles. All oocytes were thawed: out of 289 frozen oocytes, 156 survived (53.9% survival rate), we obtained 6 pregnancies (26.1%).Conclusions: Double stimulation protocol followed by double oocytes collection in the same cycle could result in more mature oocytes for patients with poor ovarian reserve who are willing for pregnancy or fertility preservation

    The effect of the static compaction on the mechanical and physical properties of asphalt concrete hot-mixes

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    The objective of this investigation was to study the effect of the static compaction effort upon the physical and mechanical properties of asphalt concrete hot mixes. To study the effect of the static compaction upon the physical properties of the asphalt mixes, six mixes were prepared using hard, well graded crushed limestone as an aggregate, blended with an 85-100 penetration grade asphalt cement. The control mix was prepared and tested in accordance with the Marshall method for mix design. The other five mixes were prepared and tested using the same procedures of Marshall except for compaction, where five different static pressures were applied. The effect of the static compaction upon the mechanical properties of the mixes was also studied. Test specimens 2.1 inches in diameter and 4.00 inches in height were compacted using different static compaction efforts. These specimens were tested in unconfined compression. Both of these studies indicated that a relationship exists between the static compaction effort and the physical and mechanical properties of the asphalt concrete mixes --Abstract, page ii

    An extremely low-noise heralded single-photon source: a breakthrough for quantum technologies

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    Low noise single-photon sources are a critical element for quantum technologies. We present a heralded single-photon source with an extremely low level of residual background photons, by implementing low-jitter detectors and electronics and a fast custom-made pulse generator controlling an optical shutter (a LiNbO3 waveguide optical switch) on the output of the source. This source has a second-order autocorrelation g^{(2)}(0)=0.005(7), and an "Output Noise Factor" (defined as the ratio of the number of noise photons to total photons at the source output channel) of 0.25(1)%. These are the best performance characteristics reported to date

    Establishment of the Regeneration System for Vicia faba L.

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    A reliable regeneration system for faba bean has been difficult to establish and therefore, the genetic improvement of Vicia faba L. was delayed. The paper describes a method of somatic embryo induction in callus of V. faba . Two Egyptian faba bean cultivars \u27Giza 2\u27 and \u2724 Hyto\u27 were used. Callus was induced from epicotyls and shoot tips cultured on MS or Gamborg medium supplemented with 3% sucrose and 0.025% (w/v) for each of ascorbic and citric acid, 0.8% agar and different concentrations of 10 mg/l BAP, 0.5 mg/l of each NAA and 2,4-dichlorophenoxyacetic acid (M1) and 1 mg/l BAP and 0.5 mg/l NAA (M2) . The media with BAP, NAA and 2,4-D were optimal for embryogenic callus induction. Somatic embryos developed after transfer of the callus to 1/2 B5 medium with no plant growth regulators. There were various stages of somatic embryo development present including globular, heart-shaped, torpedo, and cotyledonary stages. Embryos developed into plantlets and plants were regenerated. RAPD analyses were performed to investigate the genetic stability of the regenerated plants obtained from different treatments and different explants. The cultivar Giza 2 exhibited more genetic stability than cultivar 24 Hyto. In conclusion, a regeneration system was established suitable for both gene transformation and the isolation of somaclonal mutants. The regeneration system will be used in order to improve the nutritional value of faba bean

    Nanocrystalline Na0.1V2O5.nH2Oxerogel Thin Film for Gas Sensing

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    Nanocrystalline thin film of Na0.1V2O5.nH2O xerogel obtained by sol-gel synthesis was used as a gas sensor. Gas sensing properties of different gases such as hydrogen, petroleum and humidity were investigated. Applying XRD and TEM the size of the nanocrystals is found to be 7.5 nm. SEM shows a highly porous structure with submicron meter-sized voids present throughout the sample. FTIR measurement shows different chemical groups identifying the obtained series of gels. The sample was n-type semiconductor according to the thermoelectric power and electrical conductivity. It can be seen that the sensor response curves from 130°C to 150°C show a rapid increase in sensitivity for all types of gas injection, low response values for heating period and the rapid high response values for cooling period. This result may suggest that this material is able to act as gas sensor during the heating and cooling process

    Nanocrystalline Na0.1V2O5.nH2Oxerogel Thin Film for Gas Sensing

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    Nanocrystalline thin film of Na0.1V2O5.nH2O xerogel obtained by sol-gel synthesis was used as a gas sensor. Gas sensing properties of different gases such as hydrogen, petroleum and humidity were investigated. Applying XRD and TEM the size of the nanocrystals is found to be 7.5 nm. SEM shows a highly porous structure with submicron meter-sized voids present throughout the sample. FTIR measurement shows different chemical groups identifying the obtained series of gels. The sample was n-type semiconductor according to the thermoelectric power and electrical conductivity. It can be seen that the sensor response curves from 130°C to 150°C show a rapid increase in sensitivity for all types of gas injection, low response values for heating period and the rapid high response values for cooling period. This result may suggest that this material is able to act as gas sensor during the heating and cooling process

    Microwave Assisted Synthesis Of Binary Metallic Oxides For Catalysis Applications

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    Herein, versatile, and reproducible method to prepare binary metal oxides via microwave assisted synthesis. Catalysts are substances that basically speeds up chemical reactions. Ideally, bonds are formed between the catalysts and the reactants. Also, catalysts permit formation of products from the reactants. These formed products, splits off the catalyst without affecting or changing it. Catalytic kinetics studies the correlate chemical reaction rate with some properties of reactants and/or products for instance, temperature, concentration and pressure. The aim of the project is to prepare pure and bi-metal iron-based catalyst by co-precipitation method and to characterize the prepared sample using X-ray diffraction. Metal oxides nanoparticles is a field of interest in catalysis, such that these oxides are used to oxidize carbon monoxide. The samples were prepared through co-precipitation method in laboratory scale. The metals used was copper, iron and cobalt. After preparing pure sample of each metal a mix of two metals were introduced in different ratios. The samples were characterized via X-ray diffraction (XRD) and then the results were compared to exist data introduced from others research, the prepared samples XRD was having a great matching with the data retrieved from internet and we found that the metal could exist in two form of oxides and even could exist as pure metal. Each peak in the XRD figure could indicate one or more phase of the metal

    Highly efficient eco-friendly corrosion inhibitor for mild steel in 5 M HCl at elevated temperatures: experimental & molecular dynamics study

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    Laurhydrazide N?-propan-3-one was used as an eco-friendly inhibitor for the corrosion of mild steel in 5 M HCl at elevated temperatures. Various electrochemical techniques and surface characterization methods were utilized in this study. In addition, the kinetics and thermodynamic parameters were calculated and discussed. Furthermore, a geometry optimization of LHP was performed and the time-dependent density functional theory was utilized to calculate the electronic absorption spectra. Finally, frequency calculations were, also, performed on the optimized geometry. - 2019, The Author(s).This publication was supported by Qatar University Internal Grant No. GCC-2017-012. The findings achieved herein are solely the responsibility of the authors. Additionally, the authors thank the Center for Advanced Materials at Qatar University for their support.Scopu

    Relative Rate Observer Self-Tuning of Fuzzy PID Virtual Inertia Control for An Islanded microgrid

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    Expanding the usage of renewable energy in islanded microgrids leads to a reduction in its total inertia. Low inertia microgrids have difficulties in voltage and frequency control. That affected saving its stability and preventing a blackout. To improve low inertia islanded microgrids\u27 dynamic response and save their stability, this paper presented relative rate observer self-tuning fuzzy PID (RROSTF-PID) based on virtual inertia control (VIC) for an islanded microgrid with a high renewable energy sources (RESs) contribution. RROSTF-PID based on VIC\u27s success in showing remarkable improvement in the microgrid\u27s dynamic response and enhancement of its stability. Moreover, it handles different contingency conditions successfully by giving the desired frequency support. Ant colony optimization (ACO) technique is used to find the optimal values of the RROSTF-PID based on VIC parameters. Furthermore, using MATLAB TM/Simulink, RROSTF-PID based on VIC response is compared to Optimal Fuzzy PID (OF-PID) based VIC, Fuzzy PID (F-PID) based VIC, PID-based VIC, conventional VIC responses, and the microgrid without VIC response under different operation conditions
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