Queueing Models Performance Analysis in Optical Switching Network Nodes

In optical switching networks, queueing models are often used for modeling, analyzing, and evaluating the performance of switching nodes. These models determine the number of optical packets in the switch and how quickly the switch can serve the traffic. This paper examines the numerical performance of optical switching nodes under various queuing models and simulates a modeling system using the OPNET modeler simulation tool. The study estimates the expected average number of optical packets, the probability of packet loss, and the waiting delay time in an optical switch under different loads and wavelength channels.The study estimates the expected average number of optical packets, the probability of packet loss, and the waiting delay time in an optical switch under different loads and wavelength channels.The study estimates the expected average number of optical packets, the probability of packet loss, and the waiting delay time in an optical switch under different loads and wavelength channels

Velocity field measurements around Taylor bubbles rising in stagnant and upward moving liquids

Gas-liquid, two-phase flow is encountered in a wide variety of industrial equipment. A few examples are steam generators, condensers, oil and gas pipelines, and various components of nuclear reactors. Slug flow is one of the most common and complex flow patterns and it occurs over a broad range of gas and liquid flow rates. In vertical tubes, most of the gas is located in large, bullet-shaped bubbles (Taylor bubbles) which occupy most of the pipe cross section and move with a relatively constant velocity. The objectives of this work are to increase our understanding of slug flow in vertical tubes, to provide reliable data for validation of numerical models developed to predict the behaviour of slug flow, to interpret the behaviour of Taylor bubbles based on knowledge of the velocity field, and to determine the shape of the Taylor bubbles rising in stagnant and upward flowing liquid under various experimental conditions. To achieve these objectives, an experimental facility was designed and constructed to provide instantaneous two-dimensional (2-D) velocity field measurements using particle image velocimetry (PIV) around Taylor bubbles rising in a vertical 25 mm tube containing stagnant or upward moving liquids at Reynolds number based on the superficial liquid velocity (ReL = 250 to 17,800). The working fluids were filtered tap water and mixtures of glycerol and water (µ = 0.0010, 0.0050 and 0.043 Pa•s) and air. Mean axial and radial velocity profiles, axial turbulence intensity profiles, velocity vectors, and streamlines are presented for Taylor bubbles rising in stagnant and upward flowing liquids. The measurements were validated by a mass balance around the nose of the bubble. In stagnant liquids, the size of the primary recirculation zone in the near wake of the Taylor bubble depends on the inverse viscosity. For low viscosity liquid, the length of the primary recirculation zone is 1.23D (D is the tube diameter), for the intermediate viscosity it is 1.2D, and for the high viscosity it is 0.68D. Based on the velocity measurements, the minimum stable liquid slug length (the minimum distance needed to re-establish a fully-developed velocity distribution in the liquid in front of the trailing Taylor bubble) for stagnant cases was found to be in the range of 2~12D. In the flowing liquid, the flow structure of the wake depends on the relative motion between the two phases and the liquid viscosity. The wake is turbulent in all cases except at high viscosity where the wake is transitional. In general, the length of the primary recirculation zone increases with increasing liquid flow rate. For low viscosity cases, in a frame of reference moving at the bubble velocity, the length of the recirculation zone is 1.73D for ReL =9,200 and become essentially constant at 1.90D for ReL ≥ 13,600. For the intermediate viscosity, the length of the recirculation zone is 1.22D for ReL = 1,500. The length of the recirculation zone is increased to 1.34D for ReL = 3,900. For the high viscosity, the length of the recirculation region is elongated to 1.4D for ReL = 260. As the liquid flow rate increases the oscillations of the bottom surface increase and the number of small bubbles shed from the bubble bottom increases. The liquid slug minimum stable length for turbulent upward flowing liquid is around 12D. For laminar flow, the minimum stable length is 10D for ReL = 260 (high viscosity) and > 28D for ReL=1,500 (intermediate viscosity) and depends on the wake flow pattern and the liquid flow rate

Effect of Enhanced Exercise Program on Pain and Physical Activity for Patients after Total Knee Arthroplasty

Context: Total knee arthroplasty (TKA) is considered the most effective orthopedic procedure for treating knee osteoarthritis. The need for knee replacement is predicted to increase six-fold between 2005 and 2030 to reflect an increasingly yet functionally demanding population.Aim: This study aimed to evaluate the effect of an enhanced exercise program on pain and physical activity after total knee arthroplasty. Methods: Quasi-experimental (pre/post-test) design was utilized in this study. The study was carried out in the orthopedic department, at Benha University Hospital, and followed the patients through the orthopedic outpatient clinic from the beginning of May 2020 till the beginning of May 2021. A purposive sample of 64 patients was recruited to achieve the aim of this study. Four tools were used to collect the study data. These are the structured interview questionnaire to assess patients' knowledge regarding total knee arthroplasty, Barthel ADL index scale, Lysholm knee scoring scale, and Numeric Pain Rating Scale to assess the effect of the enhanced exercise program. Results: Showed that nearly two-thirds of the study sample was ≤60 years old, females, and married. The study also showed a statistically significant difference between pre-and post- enhanced exercise program in terms of total knowledge mean score among the study sample, as well as an increase in the total mean score in Barthel ADL index, decrease in Lysholm knee scoring, and pain score after one month and after three months of enhanced program exercise implementation. Conclusion: Implementing an enhanced exercise program for patients with total knee arthroplasty effectively improved knowledge, increased physical activity (Barthel ADL index), and decreased Lysholm knee scoring, and pain score. The present study recommended including an enhanced exercise program in the treatment plan for patients with total knee arthroplasty to improve patients' knowledge and practices. Also, repeating the study on a larger probability sample to achieve generalization of the findings

Effect of Designed Ureteral Stent Instructions on Patient Recovery

Context: Ureteral stent placement is performed in up to eighty percent of patients following ureteroscopy. It is associated with significant morbidity, resulting in a reduction in general health function in another eighty percent of patients.Aim: This study aimed to evaluate the effect of designed ureteral stent instructions on patient recovery.Methods: Quasi-experimental (pre/post-test) design was utilized in this study. The study was carried out at the urology department to be followed up through the urology outpatient clinic at Benha University Hospital from the beginning of February 2019 to February 2020 on a purposive sample of 134 patients. Four tools were used to collect the study data. These tools included a structured interview questionnaire to assess patients' knowledge regarding ureteral stents, a ureteral stent symptoms questionnaire, a ureteral stent discomfort test, and a patient's satisfaction assessment form. Results: Showed a mean study sample age of 43.42±6.47, 83.6% were males. The study also showed a statistically significant improvement of the study group’s knowledge in the post-operative and follow-up phases (p<0.017, <0.003), as well as a decrease in total mean score in ureteral stent symptoms and ureteral stent discomfort test (p<0.001), immediately and after designed instructions.Conclusion: Implementing designed instructions for patients with ureteral stents was effective in improving knowledge, a decrease of ureteral stent symptoms, and a decrease in patient discomfort. The study recommended manuals, information booklets, and self-instruction modules developed in areas of ureteral stent management

Oral cancer in the UAE: a multicenter, retrospective study

Aim: To determine the prevalence of various malignant oral lesions in the UAE and correlate cases of squamous cell carcinomas with age, gender, site, grade, clinical presentations at the time of diagnosis, and the prevalence of neck metastasis.Materials and methods: A multicenter, retrospective study was conducted at four major hospitals in the UAE. The study was based on histopathology reports of biopsies of oral tissues.Results: Of the 992 oral biopsy reports retrieved, 147 cases of malignant tumors were found which accounted for 14.9% of the total biopsies. Fifteen different types of malignant lesions were diagnosed, of which oral squamous cell carcinoma (OSCC) was the most prevalent and made up 11.4% of the overall oral biopsies retrieved. The commonest presentation of cancer was ulceration (31.17%), followed by lumps and white lesions. The most common site where the lesions were diagnosed was the tongue (51.9%), followed by the cheeks and lips. OSCC accounted for 77% of all malignancies reported. Neck dissections were conducted in only 20.8% of all OSCC cases diagnosed at Mafraq and Tawam hospitals, of which 43.75% showed evidence of neck metastasis.Conclusion: Oral cancer is not an uncommon disease in the UAE. This may mandate more awareness campaigning, including screening procedures for early detection of cancerous lesions and other potentially malignant oral diseases. Elective neck dissections to detect lymph node metastasis should be more routinely performed, in particular for tongue carcinomas because of the early neck involvement potential.Keywords: UAE; oral cancer; biopsy; prevalence; early detection; neck dissectio

Microbiological profiles of Neonatal sepsis in northern Egypt

Background:This study aimed at analyzing the microbiological profile of neonatal sepsis in Egypt and to determine the antibiotic susceptibility patterns of the isolated microorganisms. Methods: Two thousand and four hundred blood samples were collected from neonates showing symptoms suggestive of septicemia, inoculated into BACT/ALERT culture bottles. Positive blood culture samples were identified and tested for antimicrobial susceptibility. Results: Among the neonates included in our study, 457 (19%) neonates were positively diagnosed with sepsis. early onset neonatal sepsis (EOS) was detected in 181 (39.6%), while late-onset neonatal sepsis (LOS) in 276 (60.4%) cases. Klebsiella pneumoniae was the most commonly isolated microorganism. Staphylococcus aureus and Enterococcus spp. were the most common isolated Gram-positive bacteria. Candida spp. was more encountered in LOS.An alarming feature of the present study is the high incidence of multidrug resistant microorganisms (65%). Among Gram negative isolates (56%) of were extended spectrum beta-lactamase (ESBL) producers and (70.5%) were carbapenem resistant. In Gram positive bacteria, resistance to methicillin in S. aureus and coagulase negative staphylococci were detected in (50%) and (41%) of isolates respectively. Additionally, 17% of Enterococcus isolates were vancomycin resistant. Coclusion: Our bacteriological profile of neonatal sepsis showed that Gram negative bacteria represented the majority of isolates. Klebsiella pneumoniae was the predominant isolate. In our study, both EOS & LOS share a nosocomial infection profile, as high antimicrobial resistance was observed among our isolates. The susceptibility profiles of the isolates may urge for the change of the current used empirical therapies

Molecular Analysis of the Chlamydial Anomaly : Role of the cytoskeleton protein MreB, the serine hydroxymethyl transferase GlyA and the penicillin binding proteins from Chlamydophila pneumoniae

Chlamydiae are Gram-negative, obligate intracellular pathogens. Because of the isotonic intracellular niche of the host, a functional cell wall is dispensable in these endobacteria. Surprisingly, a nearly complete pathway for the biosynthesis of cell wall precursor lipid II is conserved in chlamydiae. Moreover, the organism is susceptible to penicillin and other antibiotics that inhibit cell wall biosynthesis. This paradox, which is known as chlamydial anomaly, raises the question about the essential role of cell wall building block lipid II in maintaining bacterial growth and replication. Cell wall biosynthesis and cell division in prokaryotes are driven by tightly coordinated, partially overlapped machineries. Therefore, it was hypothesized that lipid II, which is an essential part of both processes, is required to maintain a functional divisome in chlamydiae. The bacterial actin homolog MreB, which is found exclusively in non-spherically shaped bacteria, is considered to organize the incorporation of cell wall precursors into the side-wall, whereas the tubulin homolog FtsZ, which is ubiquitously distributed in almost all bacteria, is known to tether incorporation of cell wall building blocks at the developing septum. Unexpectedly, chlamydial genomes lack the essential central organizer of cell division ftsZ, but harbor despite of its spherical shape the rod-shape determining mreB. In this project, it was investigated how chlamydiae can divide in absence of FtsZ. It was demonstrated that cytoskeletal protein MreB might compensate for FtsZ for maintaining a functional divisome machinery in chlamydiae. It was shown that chlamydial MreB polymerizes in vitro and that polymerization is not inhibited by the blocking agent A22. As observed for MreB from B. subtilis, chlamydial MreB does not require ATP for polymerization but is capable of ATP hydrolysis in phosphate release assays. Co-pelleting and bacterial two-hybrid experiments indicate that MreB from C. pneumoniae interacts with MurF, MraY and MurG, three key components in lipid II biosynthesis. In addition, MreB polymerization is improved in the presence of MurF. These findings suggest that MreB is involved in tethering biosynthesis of lipid II and as such may be necessary for maintaining functional divisome machinery in Chlamydiaceae. While chlamydial genomes lack the alr gene encoding for alanine racemase that is responsible for D-alanine synthesis in other bacteria, several findings suggest that D-alanine should be part of chlamydial lipid II. Preliminary results on the racemization activity of the chlamydial GlyA show that the protein may provide D-alanine in chlamydiae. The sensitivity of chlamydiae to penicillin and other β-lactam antibiotics is attributed to the presence of three PBPs encoded in the chlamydial genome. Chlamydiae have three PBPs homologous to PBP2, 3 and 6a from E. coli. PBP2 and PBP3 are essential mono-functional transpeptidases in E. coli. On the other hand, the E. coli PBP6a shows a weak in vitro carboxypeptidase activity. To get insights into the functionality of the chlamydial PBPs, the three proteins were cloned, over-produced and purified successfully. Further optimizations for the established assays are still required to get clear insights into the functionality of these proteins in Chlamydiaceae

Atypical pulmonary presentation of strongyloides stercoralis hyperinfection in a patient with Philadelphia chromosome-positive acute lympoblastic leukemia

Strongyloides stercoralis is a soil-transmitted helminth endemic to tropical and subtropical regions. Rhabditiform larvae in moist soil can develop into filariform larvae that can penetrate human skin and migrate through the circulation to the lungs.1,2 These larvae escape to the alveolar space and migrate to the pharynx. Larvae can settle in the small intestine and mature into adults afterbeing swallowed in pharyngeal secretion. In immunocompromised patients, the parasite can cause autoinfection with progression to hyperinfection syndrome. We present a case of Strongyloides stercoralis hyperinfection in a patient who is immunosuppressed secondary to hyper-CVAD chemotherapy regimen for Ph+ ALL