Interference Aware Cognitive Femtocell Networks

Femtocells Access Points (FAP) are low power, plug and play home base stations which are designed to extend the cellular radio range in indoor environments where macrocell coverage is generally poor. They offer significant increases in data rates over a short range, enabling high speed wireless and mobile broadband services, with the femtocell network overlaid onto the macrocell in a dual-tier arrangement. In contrast to conventional cellular systems which are well planned, FAP are arbitrarily installed by the end users and this can create harmful interference to both collocated femtocell and macrocell users. The interference becomes particularly serious in high FAP density scenarios and compromises the ensuing data rate. Consequently, effective management of both cross and co-tier interference is a major design challenge in dual-tier networks. Since traditional radio resource management techniques and architectures for single-tier systems are either not applicable or operate inefficiently, innovative dual-tier approaches to intelligently manage interference are required. This thesis presents a number of original contributions to fulfill this objective including, a new hybrid cross-tier spectrum sharing model which builds upon an existing fractional frequency reuse technique to ensure minimal impact on the macro-tier resource allocation. A new flexible and adaptive virtual clustering framework is then formulated to alleviate co-tier interference in high FAP densities situations and finally, an intelligent coverage extension algorithm is developed to mitigate excessive femto-macrocell handovers, while upholding the required quality of service provision. This thesis contends that to exploit the undoubted potential of dual-tier, macro-femtocell architectures an interference awareness solution is necessary. Rigorous evidence confirms that noteworthy performance improvements can be achieved in the quality of the received signal and throughput by applying cognitive methods to manage interference

Retracted: Histopathological Correlation Between Prostatic Adenocarcinoma in Transrectal Ultrasound Guided Biopsies and Radical Prostatectomy Specimens

Introduction: Differences in Gleason grade in transrectal ultrasonography (TRUS) biopsies and radical prostatectomy (RP) specimens are well documented in literature. Keeping in view the limitations of Gleason grading system, Epstein JI grade group system was introduced. Various other parameters also have a significant role in predicting the pathological stage, extraprostatic extension, status of surgical margins and metastatic disease in regional lymph nodes. RP is performed at limited centres in Pakistan. Till date, no comparison of the histopathological findings in 12-core TRUS and RP specimens had been performed at the national level. Our study is aimed at generating local data in this context. Materials and Methods: This was a crosssectional study and non-probability consecutive sampling was performed. It was conducted at Histopathology Department, Shifa International Hospital, Islamabad, from January 2008 to December 2014. Gleason scores of 20 RP specimens were compared to Gleason scores of TRUS biopsies of same patients. Concordance in Gleason score and grade groups with laterality, perineural invasion was also studied. Results: Out of 20 RP cases, 40% (n = 8) had a Gleason score of 6, 30% (n = 6) had score 7, 20% (n = 4) had score 8 and 15% (n = 3) had score 9. Compared to the TRUS biopsy, RP Gleason score was concordant in 11 cases (55%), higher in 7 cases (35%) and lower in 2 cases (10%). TRUS involvement was unilateral in 10 cases (50%) and bilateral in 10 cases (50%). However, bilateral involvement of RP specimen was seen in 14 cases (70%) and unilateral in 6 cases (30%). Thus, better tumour yield was observed in RP specimens i.e., bilateral involvement in RP specimens was found in additional 5 cases (25%). Perineural involvement was higher in RP specimen i.e., 12 cases (60%), compared to 5 cases (25%) in TRUS biopsies. Its concordance was significantly higher in those with Gleason score of equal to or more than 7 (83%) and low in score less than score 7 (17%). Conclusion: When comparing RP to initial TRUS biopsies, Gleason score was upgraded in 35% and downgraded in 10% of cases. Bilateral involvement in 25% of cases of RP specimens was underestimated as unilateral involvement in TRUS biopsies. Perineural involvement with high Gleason score was also seen.&nbsp

An interference-aware virtual clustering paradigm for resource management in cognitive femtocell networks

Femtocells represent a promising alternative solution for high quality wireless access in indoor scenarios where conventional cellular system coverage can be poor. They are randomly deployed by the end user, so only post deployment network planning is possible. Furthermore, this uncoordinated deployment creates severe interference to co-located femtocells, especially in dense deployments. This paper presents a new architecture using a generalised virtual cluster femtocell (GVCF) paradigm, which groups together FAP into logical clusters. It guarantees severely interfering and overlapping femtocells are assigned to different clusters. Since each cluster operates on different band of frequencies, the corresponding virtual cluster controller only has to manage its own FAPs, so the overall system complexity is low. The performance of the GVCF algorithm is analysed from both a resource availability and cluster number perspective. Simulation results conclusively corroborate the superior performance of the GVCF model in interference mitigation, particularly in high density FAP scenarios

Spinal muscular atrophy:clinical spectrum and genetic mutations in Pakistani children

Background: In Pakistan the rate of consanguineous marriages is high, thus, the chance of incidence of autosomal recessive disorders is likely to be high. The aim of this study is to investigate the clinical characteristics and genetics of spinal muscular atrophy (SMA) in children who presented to Aga Khan University, Karachi.Materials and Methods: This study was a retrospective review of the medical charts of children (neonate: 15 years) with discharge diagnosis of SMA during last 10 years. Demographic features, consanguinity, and diagnostic analysis (including genetic analysis) were noted.Results: During the study period 67 children had a discharge diagnosis of SMA. Werdnig Hoffman disease (SMA type I) was the commonest variant seen in 37 (56%) children. Overall 68% were infants. High parental consanguinity was observed in 68% of the study cohort. The history of delayed development and undiagnosed early death was observed in the families of 19 children. Genetic testing was performed in 22 (33%) children. Survival motor neuron (SMN) 1 gene deletion was found in 19 (86%) of the 22 patients in whom the gene analysis was done and 13 (68%) were also positive for neuronal apoptosis inhibitory proteins (NAIP) deletion.Conclusion: SMA is not an uncommon neurodegenerative disorder in Pakistan and SMA type I was the most common type. SMN1 gene deletion was the most common genetic deletion found in this study. In addition, family history of developmental delay and frequent early deaths highlights the need for implementation of prenatal diagnosis for early detection, effective control, and management of this disorder in Pakistan

Fulminant invasive aspergillosis of the mediastinum in an immunocompetent host: a case report

Introduction: Invasive aspergillosis is a serious complication in immunocompromised patients. It is an opportunistic disease, which predominantly occurs in the lungs, although dissemination to virtually any organ is possible. Invasive aspergillosis in an immunocompetent patient with extension to the mediastinum has rarely been reported. Here, we present the case of a patient with no apparent immunodeficiency state, who presented with Aspergillus endocarditis and fulminant invasive aspergillosis with extensive involvement of the mediastinal structures, which ultimately was responsible for her death. To the best of our knowledge, this is the first reported case in the literature on fulminant invasive mediastinal aspergillosis with extension to the pulmonary vasculature and concomitant Aspergillus endocarditis in an apparently immunocompetent patient without pre-existing lung disease. Case presentation: Our patient was a previously healthy 47-year-old Asian woman, who presented to our emergency room with severe progressive shortness of breath of one month’s duration, associated with orthopnea and unstable vital signs. Conclusion: Invasive aspergillosis has been described in the presence of pulmonary disease, such as chronic obstructive pulmonary disorder, and one case has been reported in a patient without preexistent disease, but none of these have been fatal. Our case is therefore the first reported case of its kind. Our case shows that fulminant aspergillosis can occur in an immunocompetent host and can be fatal. We conclude that invasive aspergillosis should not be excluded from the differential diagnosis on the basis of immunocompetency

Fulminant invasive aspergillosis of the mediastinum in an immunocompetent host: a case report.

Introduction: Invasive aspergillosis is a serious complication in immunocompromised patients. It is an opportunistic disease, which predominantly occurs in the lungs, although dissemination to virtually any organ is possible. Invasive aspergillosis in an immunocompetent patient with extension to the mediastinum has rarely been reported. Here, we present the case of a patient with no apparent immunodeficiency state, who presented with Aspergillus endocarditis and fulminant invasive aspergillosis with extensive involvement of the mediastinal structures, which ultimately was responsible for her death. To the best of our knowledge, this is the first reported case in the literature on fulminant invasive mediastinal aspergillosis with extension to the pulmonary vasculature and concomitant Aspergillus endocarditis in an apparently immunocompetent patient without pre-existing lung disease. Case presentation: Our patient was a previously healthy 47-year-old Asian woman, who presented to our emergency room with severe progressive shortness of breath of one month’s duration, associated with orthopnea and unstable vital signs. Conclusion: Invasive aspergillosis has been described in the presence of pulmonary disease, such as chronic obstructive pulmonary disorder, and one case has been reported in a patient without preexistent disease, but none of these have been fatal. Our case is therefore the first reported case of its kind. Our case shows that fulminant aspergillosis can occur in an immunocompetent host and can be fatal. We conclude that invasive aspergillosis should not be excluded from the differential diagnosis on the basis of immunocompetency