Cooperative Access in Cognitive Radio Networks: Stable Throughput and Delay Tradeoffs

In this paper, we study and analyze fundamental throughput-delay tradeoffs in cooperative multiple access for cognitive radio systems. We focus on the class of randomized cooperative policies, whereby the secondary user (SU) serves either the queue of its own data or the queue of the primary user (PU) relayed data with certain service probabilities. The proposed policy opens room for trading the PU delay for enhanced SU delay. Towards this objective, stability conditions for the queues involved in the system are derived. Furthermore, a moment generating function approach is employed to derive closed-form expressions for the average delay encountered by the packets of both users. Results reveal that cooperation expands the stable throughput region of the system and significantly reduces the delay at both users. Moreover, we quantify the gain obtained in terms of the SU delay under the proposed policy, over conventional relaying that gives strict priority to the relay queue.Comment: accepted for publication in IEEE 12th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), 201

Volumetric Soft Tissue Changes After Using Injectable Platelet-Rich Fibrin (I-PRF) Versus Subepithelial Connective Tissue Graft in Interdental Papillae Defects: A Randomized Controlled Clinical Study

Background: Lost interdental papillae in the esthetic region are of great concern from the esthetic and functional point of view. We elicit a clinical study of papillary reconstruction in this article using injectable platelet-rich fibrin (I-PRF) as a nonsurgical procedure and compare its results to those of the subepithelial connective tissue graft (SECTG), being considered the gold standard method used to reconstruct interdental papillae. Methods: Twenty-four patients seeking treatment for black triangles were randomized into two groups: group A patients were treated with the SECTG technique, and group B patients were treated with I-PRF. Four injections were given at each papilla site at baseline, two-, four-, and six-week intervals to ensure optimal esthetics. Pain, clinical, and volumetric assessments were done. Volumetric assessment was completed through intraoral scanning of the papilla site at baseline and after six months, after which the results were obtained by superimposition of both scans. Results: Group A (5.08 ±2.15) had a significantly higher mean pain score value than group B (1.17 ±0.94) (p < 0.001). Group B (0.31 ±0.21) had a higher mean value of volumetric changes at the interdental papillae than group A (0.25 ±0.17), yet the difference was not significant (p = 0.517). Conclusion: Injectable platelet-rich fibrin gave comparable results to SECTG in Nordland Class I defects only, provided that the injection protocol was once every 15 days for a two-month period. Patients treated with I-PRF were more satisfied with the procedure and the results than patients who were treated with SECTG

Relation of serum visfatin level and uterine artery Doppler to preeclampsia

Background: Preeclampsia (PE) is a significant cause of remarkable fetomaternal morbidity and mortality worldwide. Visfatin is 52 KDa novel adipokine, pre B cell colony enhancing factor (PBEF) which could be used as a biochemical marker predictor or a diagnostic tool for preeclampsia. Trans abdominal pulsed Doppler ultrasound (US) monitor the impedance to blood flow in the uterine arteries in pregnant females and those with preeclampsia. Visfatin has been implicated in the pathogenesis of preeclampsia with a limited contradictory. The aim of our study is to monitor the risky pregnant females through Visfatin level and transabdominal pulsed Doppler of the uterine artery.Methods: Assessment of the serum Visfatin levels in the maternal circulation of preeclamptic pregnant females wether mild or severe, and compared to those in the normal pregnant subjects as control through recruitment of cases of mild PE (n=40), severe PE (n=40), normal pregnant subjects (n=60) in a cross sectional study where the cases were of the patients hospitalized at El Shatby Hospital of Obstetrics and Gynecology, and the control subjects were of referrals to the outpatient departments. Fasting blood samples were drawn, kept at -20 degree centigrades , enzyme linked immune sorbant assay (ELISA) Test was performed on them to determine the Visfatin level and recorded the uterine arteries pulsatility index through transabdominal doppler ultrasound. Lastly, the data were analysed using (F test) ANOVA statistical method.Results: Amongst the groups, Serum visfatin level was significantly higher in the severe preeclamptic group rather than the normal pregnant group and those with mild preeclampsia (p<0.001). Uterine artery pulsatility index was significantly higher in the severe preeclamptic group rather than the normal pregnant group and those with mild preeclampsia (p<0.001).Conclusions: Severe preeclamptic pregnant females were shown to represent higher circulating visfatin levels as one of the most recent biochemical markers of preeclampsia, higher uterine artery pulsatility index compared to normal pregnant and those with mild preeclamptic groups of women

Factors affecting the bid/no bid decision in the Palestinian construction industry

Purpose – The purpose of this paper is to identify and rank the factors that affect the bid/no bid decision according to their relative importance from the perspective of the contracting parties operating in the Gaza Strip, Palestine. Design/methodology/approach – The objectives of this research were investigated through a postal questionnaire, which covered a randomly selected sample of 63 contractors, 29 clients and 13 consultants operating in the construction industry in the Gaza strip. The questionnaire was structured based on related literature, the pilot study and actual factors affecting bidders' decisions to bid or not that arise from special conditions in the Gaza Strip. A total of 78 factors that affect the bid/no bid decision were identified. These factors were then ranked according to their relative importance to contracting parties operating in the Gaza Strip, Palestine. Findings – The results illustrate that the financial

Factors affecting bid/no bid decision in the Gaza Strip–contractorsperspectives

To bid or not to bid for a certain project is considered to be a crucial decision for contractors' survival. The objective of this paper is to identify and rank the factors that affect the bid/no bid decision according to their relative importance from the perspective of the local contractors operating in the Gaza Strip, Palestine. A total of seventy-eight factors were identified through a comprehensive literature review to evaluate the most important factors that affect the contractors' decisions to bid or not in the Gaza strip. A survey was conducted on a sample of seventy three contractors classified under the building category, and sixty five of them responded with response rate 89%. The results illustrate that, the financial capability of the contractors, the reputation of the clients, the financial capability of the clients, the financial values of the project, the availability of construction raw materials in the local markets, and the stability of the construction industry were the most critical factors affecting the contractors bid-no bid decisions. This study suggests that contractors and clients should improve their financial systems and capabilities in order to stay in business

Predictors of Angio access failure in end stage renal disease patients in Southern Egypt

Background: Hemodialysis (HD) seems to be the most often used Renal Replacement Therapy (RRT) modality worldwide, and it is the primary modality in the majority of instances with extended RRT. The ability to provide our patients with high-quality HD treatment while also increasing their chances of survival is heavily reliant on the functionality of the vascular access (VA). Despite the fact that it is a very necessary component of all clinical practise standards, it is the most expensive individual component of RRT.Objectives: This study was aimed at comparing between the group with Angio access failure and group without Angio access failure and predicting Angio access failure among end stage renal failure patients in Southern Egypt.Subjects and Methods: a prospective cohort study among 125 patients with end stage renal failure at Aswan University. The research comprised patients who had NCVA placement [intra-atrial catheter (IAC) and trans-lumbar catheter (TLC)] between January 1, 2020, and December 31, 2020.Results: The duration of previous RRT was significantly higher among the Angio access failure than the group without Angio access failure. In multivariate analysis using logistic regression, the age, duration of previous RRT, diabetes, IHD (ischemic heart disease), PVD (peripheral vascular disease) and CVD (cardiac vascular disease) were significantly direct predictors of the Angio access failure in the first one year.Conclusion: In conclusion the failure of Angio access was positively associated with age, previous RRT and other comorbidities

Prognostic and Therapeutic Implications of Lymphocytes in Hematological Disorders and Solid Malignancies

An efficient and specific cytotoxic immune response against a tumor requires a complex, rapidly evolving interaction between various immune cell types in the adaptive and innate immune system. This pliable interplay is a relentless process that has been concisely organized in three different phases: elimination, equilibrium, and escape. The identification of key immune players and molecules involved in this interplay has been crucial for the introduction of reliable prognostic factors and effective therapeutic protocols against cancers. In this chapter, we aim to depict the roles of these distinct immune cell subsets, summarize the prognostic value of immune cells in different cancer types, and discuss briefly the principles of different immunotherapeutic approaches against hematologic malignancies and solid tumors