205 research outputs found

    An Efficient Measure for Nonlinear Distortion Severity due to HPA in Downlink DS-CDMA Signals

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    This paper deals with the nonlinear distortion (NLD) effects of high power amplifiers (HPAs) on direct sequence-code division multiple access systems. Such a distortion drastically degrades the system performance in terms of bit error rate (BER) degradation and spectral regrowth. Much effort has been conducted to minimize NLD. A key requirement to do so is to define a certain measure for the HPA nonlinearity, which when reduced often allows NLD to also be reduced. Several measures were proposed such as peak-to-average power ratio, instantaneous power variance, and cubic metric. In this paper, we show that such measures are not closely related to NLD and their reduction does not always lead to optimum performance. Hence, we introduce an efficient measure, namely, nonlinearity severity (NLS), to characterize NLD effects, as an alternative to the existing measures. The NLS is characterized by having direct link to the system performance as it is formulated based on the signal characteristics contributing to BER performance and spectral regrowth. Additionally, a major advantage of the NLS measure is that it is linked to the IBO level allowing

    Ventilatory functions response to breathing training versus aerobic training in asthmatic children

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    Background: There is worldwide public interest in physical therapies for asthma. Objective: To compare the effects of a program of breathing training and aerobic training on ventilatory functions in children with bronchial asthma. Methods: Forty asthmatic children from both genders (22 boys and 18 girls) were recruited to participate with age range 6-13 years. The children were divided into two groups of equal number, group A received a program of breathing training and group B received a program of aerobic training on cycle ergometer three times per week for three months. Ventilatory functions were measured before beginning and after finishing the training. Results: The results showed high statistical significant differences in the FVC, FEV1, PEF, FEF25-75% and MVV within each group while on comparing the two groups, the ventilatory functions were comparable. Conclusion: Breathing training and aerobic training can be used as a safe complement to medical treatment in asthma.Keywords: Asthmatic children; ventilatory functions, breathing training; aerobic trainingEgypt J Pediatr Allergy Immunol 2012;10(1):33-3

    Integrated audio-video synchronization system for use in multimedia applications

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    The use of multimedia system have moved beyond the studio barriers and into the homes. As computers become more powerful, multimedia systems become more realizable on the PC. As these multimedia systems become more complicated, the need to provide complex integration systems and synchronization arises. To develop a multimedia system, one must ensure that a synchronization approach is in place to solve the timing issues related to the media types involved. Temporal information in multimedia systems must be maintained such that no loss of coherency is endured. The system must ensure that no matter how much processing is performed on the signals, the output has to maintain the temporal integrity of the signals as they were when they were inputted. This thesis develops a multimedia system that processes two media streams. Audio and video streams are fed to the system. The system produces an object segmented output, (silhouettes of the object) along with the recognized speech from the audio. The speech that is to be recognized by the system is spoken by the objects/speakers. The challenge lies in maintaining the synchronization and integrating the video and the recognized speech at the output. Note that the system is a stream based system by that the video and audio are continuously captured and processed. This thesis presents a solution to the problem of synchronization in the temporal domain and the overall integration of the multimedia system. The thesis presents a time-stamp approach to solve the synchronization problem between audio and video signals. This approach is adaptive to the cases where the video processing delay is larger or smaller than the audio processing delay. The contributions include the verification of using time-stamps in the synchronization process and that it is possible to synchronize heavily delayed signals. The system requires an integration process such that the audio and video signals are integrated with one another at the outpu

    Effect of oxytocin infusion versus tranexamic acid on reducing blood loss during hysteroscopic myomectomy: a randomized controlled trial

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    Background: Women undergoing hysteroscopic myomectomy are prone to significant blood loss and hematological disturbances. Oxytocin is a uterotonic drug, used mainly in obstetric practice. Tranexamic acid is a haemostatic drug that has been used to reduce blood loss after trauma and in many surgeries. The aim of our study was to compare the safety and efficacy of oxytocin versus tranexamic acid in reducing perioperative blood loss during hysteroscopic myomectomy.Methods: This study included 60 patients scheduled for hysteroscopic myomectomy allocated into 2 groups: group A: received 10 mg/kg of tranexamic acid slowly intravenous after induction of anesthesia, while group B: received infusion of 10 IU of oxytocin at a rate of 400 mIU/min throughout the procedure. Preoperative and postoperative hemoglobin and hematocrit levels, need for blood transfusion, duration of operation, complications and medications adverse effects were recorded.Results: The 2 groups were comparable in terms of the mean difference between preoperative and postoperative hemoglobin a hematocrit levels, operative time, operative complication and medications’ adverse effects. No patients needed blood component transfusion in either group.Conclusions: It can be concluded that tranexamic acid and oxytocin are equally effective in reducing blood loss and transfusion requirements during hysteroscopic myomectomy with comparable good safety profiles. Both of them can be used according to availability and surgeon preferences

    L-Carnitine Improves the Asthma Control in Children with Moderate Persistent Asthma

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    The objective. was to investigate L-Carnitine level and the effects of its supplementation in children with moderate persistent Asthma. Methods. Free and total serum carnitine levels were measured in 50 children having moderate persistent asthma and 50 healthy control children. The patients group was randomly divided into two subgroups. Subgroup A was supplemented with L-carnitine for 6 months while subgroup B was used as a placebo controls. Both subgroups were assessed by pulmonary function tests (PFT) and childhood-asthma control test (C-ACT) before and 6 months after carnitine supplementation. Results. Total and free carnitine levels were significantly lower in patient group than in control group. PFT and C-ACT showed significant improvements in asthmatic children supplemented with L-carnitine than in those who were not supplemented. Conclusion. L-carnitine levels were initially lower in moderate persistent asthmatic children as compared to healthy control children. Asthmatic children who received L-carnitine supplementation showed statistically significant improvement of C-ACT and PFT

    Core-in-cup/liquisol dual tackling effect on azelnidipine buccoadhesive tablet micromeritics, in-vitro release, and mucoadhesive strength

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    Reduced bioavailability of azelnidipine is related to its poor aqueous solubility and extensive first-pass metabolism, which hinder its efficacy. These problems were addressed by implementing (1) a liquisol technique for promoting the dissolution rate in a controlled-release manner and (2) a core-in-cup buccoadhesive drug delivery system as an alternative to the oral route. A 33 factorial design was used to study the effects of polymer type (sodium carboxymethyl cellulose (CMC Na), chitosan, or Carbomer P940) concentration (5, 10 or 15 %) and preparation technique (simple mix, liquisol or wet granulation) on the dissolution and mucoadhesion of core-in-cup azelnidipine buccoadhesive tablets. Tablet micromeritics, swelling index, mucoadhesive strength and in vitro release were characterized. Statistical analyses of these factors showed significant effects on the studied responses, where F#16 prepared by the liquisol technique and containing 15 % CMC Na was chosen with an overall desirability of 0.953

    Effect of nanoparticles on biological contamination of in vitro cultures and organogenic regeneration of banana

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    Abstract This study aimed to identify biological contaminants of banana in vitro cultures. We also tested the effect of Zn or ZnO nanoparticles on elimination of some bacterial and fungal contaminants and their influence regeneration. Nine strains of bacterial contaminants (Cellulomonas uda, Cellulomonas flarigena, Corynebacterium panrometabolum, Bacillus megaterium, Staphylococcus spp., Klebsiella spp., Erwinia cypripedii, Pseudomonas spp. and Proteus spp.) and four fungal (Fusarium spp., Aspergillus spp., Penicillium spp. and Candida spp.) contaminants were identified in nanoparticles-free media of banana in vitro cultures. They eventually led the explants death. The contamination-free cultures of banana in vitro cultures were obtained as a result of application of nano Zn and ZnO particles to the culture MS media, with no negative effect on regeneration. The callus growth decreased while total proline as well as SOD, CAT and POX activities were increased significantly, when the nanoparticles doses increased. The highest percent of somatic embryogenesis was observed in MS media supplemented with 100 mg/L nano Zn followed by nano ZnO. Excellent shooting, rooting and regenerated plantlets were observed also in MS+100 mg/L nano Zn and ZnO. Regenerated plantlets were successfully acclimatized with about 98% efficiency for the experimental period (one month). Nanoparticles treated somaclones accumulated more proline, chlorophyll, antioxidant enzymes activity and developed more dry weight accumulation than the control. In conclusion, the microbial contaminants in banana in vitro culture can effectively be eliminated by incorporation of nano Zn and nano ZnO particles on growth media at different concentrations. However, 100 mg/L dose was preferable because it showed the best effects on increasing the regeneration of plantlets with well-formed root systems. Further studies are needed to investigate the mechanisms and the side effects of nanoparticles on genetic stability of banana in vitro cultures
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