DESIGN & IMPLEMENTATION OF FRACTIONAL – N FREQUENCY SYNTHESIZER

This research involves design & implementation of fractional – N frequency synthesizer with the following specifications: Frequency range (2350– 2750) MHz,Step size (1 kHz), Switching time 8.9 μs, & phase noise @10 kHz = -115dBc & spurious -69 dBc The third order Fractional –N technique was chosen to satisfy the design requirements. In this system the modulator placed on digital phase-locked loop to control the fractional value of the frequency division ratio thereby eliminating spurious and allowing good phase noise performance. The development in I.C. technology provides the simplicity in the design of fractional –N frequency synthesizer because it implements the phase frequency detector(PFD) , prescalar,modulator & reference divider in single chip. Therefore our system consists of a single chip contains (low phase noise PFD, charge pump, prescalar, modulator & reference divider), voltage controlled oscillator , loop filter & reference oscillator. The application of this synthesizer in frequency hopping systems, wireless transceivers ,GSM & radar because it has high switching speed ,low phase noise & low spurious level

PHYSICO-CHEMICAL ASSESSMENT OF WATER SAMPLES COLLECTED FROM SOME SELECTED STREAMS AND RIVERS IN DISTRICT GILGIT, PAKISTAN

This study aims to provide information about the drinking water quality of two streams in Chakarkote Sai and Demote Sai and two rivers in Gilgit and Hunza. Parameters were tested including physical, and chemical. The physical parameters were temperature, pH, electric conductivity (EC), total dissolved solids (TDS), turbidity, dissolved oxygen (DO), ammonia (NH4),total nitrogen (TN), total phosphorus (TP) and reactive orthophosphate (PO4). The ranges of these parameters set by WHO and NEQs, as most of the Asian countries also follow the WHO standards. All the samples were tested in the EPA certified laboratory of biological sciences department Karakorum international university Gilgit Baltistan. The minimum and maximum values of temperature 15.2-18.4, PH 6.78-6.09, EC 109.3-297 µS, TDS 53.8-149 ppm, Turbidity 0.29-88.4 NTU, DO 7.1-8.9 mg/l, TN 5.63-7.13 mg/l, NH4 0.0106-0.0151 mg/l, TP 0.042-0.143mg/l, and PO4 0.0059-0.016 mg/l. Independent T test was applied separately for both streams and rivers to determine significant difference of water properties with respect to location wise. Water parameters like DO and TP were significantly, while temperature, PH, EC, TDS, turbidity, TN, NH4, PO4 were non-significant in streams and TDS, turbidity, DO and TN were significant, while temperature, PH, EC, NH4, TP, PO4 were non-significant in rivers according to area wise

Early Cerebrovascular Silent Changes in Long-Standing End-Stage Renal Disease Patients on Hemodialysis Value of Adding Advanced Unenhanced MRI Sequences to Imaging Protocols

Background: End-Stage Renal Disease (ESRD) patients on hemodialysis suffered from many central and peripheral neurological insults. Aim of the work:This study aimed to assess the value of using MRA, MRV, and SWAN sequences in early visualization of the silent cerebrovascular complications in those patients. Patients and Methods: Our study was conducted on forty-five patients with well-documented ESRD on regular hemodialysis for more than 5 years with no neurological manifestation, all undergone unenhanced MRI, DWI with ADC and measuring the ADC value, SWAN, MRA, and MRV. Results: we found that 11% of cases have acute infarction at the basal ganglia region. 36.7% of patients are diagnosed with intracerebral hemorrhage, only 26.7% of them are seen by the conventional MRI, and 16.7% of cases showed microbleeds on SWAN with normal conventional MRI. The sensitivity and specificity of SWAN with ADC value to detect brain hemorrhage are 100% and 88.8% respectively. Conclusion: Visualization of cerebrovascular complications such as infarction, hemorrhage, atherosclerosis, and arterial and venous occlusion using DWI with ADC, MRA, MRV, and SWAN and is very useful in early management and better prognosis of ESRD patients even with silent complications that don’t give up symptoms with high sensitivity and specificity of SWAN in early detection of hemorrhage and microbleeds

Parameters Affecting the Extraction Process of Jatropha Curcas Oil Using a Single Screw Extruder

The most commonly used technique to separate oil and cake from J. curcas seeds is mechanical extraction. It uses simple tools such as a piston and a screw extruder to produce high pressure, driven by hand or by engine. A single screw extruder has one screw rotating inside the barrel and materials simultaneously flow from the feed to the die zone. The highest oil yield can be obtained by a well-designed oil press as well as finding the optimum conditions for all parameters involved during the extraction process. The influence of the parameters in a single screw extruder was studied using finite element analysis and computational fluid dynamics simulation with ANSYS POLYFLOW. The research focused on predicting the velocity, pressure and shear rate in the metering section that influenced the screw rotational speed and mass flow rate. The obtained results revealed that increasing the screw rotational speed will increase the pressure, velocity and shear rate. Meanwhile, increasing the mass flow rate results in decreasing the pressure while the velocity and shear rate remain constant

Extranodal Natural Killer/T-cell Lymphoma in a Child with a Prior History of Nasal Trauma: a Case Report

Introduction: Facial lesions usually have a benign self-limited prognosis, but in rare cases they have a poor outcome. Extranodal natural killer/T-cell lymphoma (ENK/TCL) is a rare aggressive lesion presenting with a midline facial lesion that can easily be misdiagnosed. Diagnosis is often difficult and requires a thorough clinical examination and the use of immunohistochemistry for analysis of biopsies. Such malignancies affecting the head and neck area provide an interesting but difficult diagnosis. The purpose of this article is to report a severe case of ENK/TCL-nasal type in a boy with a previous history of nasal trauma. Case presentation: An 11-year-old boy was referred to the maxillofacial unit of Sulaimany Teaching Hospital, Iraq, with midline facial destruction. The patient stated that about 6 months prior he had fallen down and suffered nasal trauma; 3 months after the trauma, an asymptomatic ulcer appeared and gradually increased in size. Two biopsies were performed with no conclusive results. In the third biopsy, histology showed atypical lymphoid tissue surrounded by intense necrosis. The diagnosis was confirmed by immunohistochemistry. The treatment of choice was chemotherapy followed by radiotherapy. The patient had a satisfactory response but 2 months later during chemotherapy the patient unfortunately died from a pulmonary embolism. Conclusion: Suspicious midline ulcerative lesions in the head and neck region must have ENK/TCL considered in the differential diagnosis and repeated biopsies may be necessary to confirm the diagnosis

Extranodal Natural Killer/T-cell Lymphoma in a Child with a Prior History of Nasal Trauma: a Case Report

Introduction: Facial lesions usually have a benign self-limited prognosis, but in rare cases they have a poor outcome. Extranodal natural killer/T-cell lymphoma (ENK/TCL) is a rare aggressive lesion presenting with a midline facial lesion that can easily be misdiagnosed. Diagnosis is often difficult and requires a thorough clinical examination and the use of immunohistochemistry for analysis of biopsies. Such malignancies affecting the head and neck area provide an interesting but difficult diagnosis. The purpose of this article is to report a severe case of ENK/TCL-nasal type in a boy with a previous history of nasal trauma. Case presentation: An 11-year-old boy was referred to the maxillofacial unit of Sulaimany Teaching Hospital, Iraq, with midline facial destruction. The patient stated that about 6 months prior he had fallen down and suffered nasal trauma; 3 months after the trauma, an asymptomatic ulcer appeared and gradually increased in size. Two biopsies were performed with no conclusive results. In the third biopsy, histology showed atypical lymphoid tissue surrounded by intense necrosis. The diagnosis was confirmed by immunohistochemistry. The treatment of choice was chemotherapy followed by radiotherapy. The patient had a satisfactory response but 2 months later during chemotherapy the patient unfortunately died from a pulmonary embolism. Conclusion: Suspicious midline ulcerative lesions in the head and neck region must have ENK/TCL considered in the differential diagnosis and repeated biopsies may be necessary to confirm the diagnosis

Prevalence of Muscle Dysmorphia and Associated Health Activities in Male Medical Students in Karachi, Pakistan

Background: Muscle Dysmorphia (MD) is a subtype of body dysmorphic disorder (BDD) and is currently classified under anxiety disorders (subheading: Obsessive-compulsive disorder) in DSM 5. MD is hypothesized to affect the self-esteem and social outlook of the younger generation. MD shows a higher rate in males and may influence their self-confidence rendering them more prone towards using steroids, supplementary proteins and other drugs to alter their physical outlooks as shown in previous studies. This problem has been on the rise lately due to revolutionary advancement in the media and film industry and the abrupt changes about the standards of physical good looks and body shapes. With the lack of studies done in our population, our study will be helpful to consider the prevalence of the disease in our setting and increase awareness in the general public and clinicians. We hope to help clinicians/ therapists find better options in managing the disease. Materials: We performed a cross-sectional study with a sample size of 246 medical school students in Karachi to collect data through self-administered questionnaires. We used the DSM 5 criteria for the diagnosis of BDD and additional questions on the presence of MD. Nutritional habits, exercise routines, use of supplements and drugs were also obtained for exploratory analysis. Results: Our study predicted the prevalence of MD to be 25%. Other main findings included statistical significant associations between MD and the thoughts and practice of steroid use for muscularity. Conclusion: MD is an underdiagnosed and often unrecognized disease that we believe has significant consequences for the young male population. Further work is needed on this in our part of the world. Our research, we believe, can be a stepping stone for further studies that would incorporate wider populations

Potential Models for Radiative Rare B Decays

We compute the branching ratios for the radiative rare decays of B into K-Meson states and compare them to the experimentally determined branching ratio for inclusive decay b -> s gamma using non relativistic quark model, and form factor definitions consistent with HQET covariant trace formalism. Such calculations necessarily involve a potential model. In order to test the sensitivity of calculations to potential models we have used three different potentials, namely linear potential, screening confining potential and heavy quark potential as it stands in QCD.We find the branching ratios relative to the inclusive b ->s gamma decay to be (16.07\pm 5.2)% for B -> K^* (892)gamma and (7.25\pm 3.2)% for B -> K_2^* (1430)gamma for linear potential. In the case of the screening confining potential these values are (19.75\pm 5.3)% and (4.74\pm 1.2)% while those for the heavy quark potential are (11.18\pm 4.6)% and (5.09\pm 2.7)% respectively. All these values are consistent with the corresponding present CLEO experimental values: (16.25\pm 1.21)% and (5.93\pm 0.46)%.Comment: RevTeX, 6 pages, 1 eps figur

Urban wastewater: A valuable resource for agriculture - A case study from Haroonabad, Pakistan

Waste waters / Irrigation water / Water reuse / Economic analysis / Soil properties / Households / Water availability / Water use / Water quality / Groundwater / Public health / Risks / Case studies