Design and simulation of high frequency colpitts oscillator based on BJT amplifier

Frequency oscillator is one of the basic devices that can be used in most electrical, electronics and communications circuits and systems. There are many types of oscillators depending on frequency range used in an application such as audio, radio and microwave. The needed was appeared to use high and very high frequencies to make the rapid development of advanced technology Colpitts oscillator is one of the most common types of oscillator, it can be used for radio frequency (RF), that its output signal is often utilized at the basic of a wireless communication system in most application. In this research, a Colpitts oscillator is comprised from a bipolar junction transistor (BJT) amplifier with LC tank. This design is carrying out with a known Barkhausen criterion for oscillation. Firstly, is carried out using theoretical calculation. The secondary is carried out using simulation (Multisim 13). All the obtained result from the above two approaches are 10 MHz and 9.745 MHz respectively. This result is seen to be very encouraging

The Accuracy of FNAC for Diagnosis of Breast Carcinoma in Gezira State, Central Sudan

Background: Breast cancer is a leading cause of death in many countries worldwide and breast lesions remain a common diagnostic dilemma. Fine-needle aspiration cytology (FNAC) has been suggested as the most important, first line, minimally invasive procedure in the management of patients with breast lesions. Objective: The aim of this study is to assess the diagnostic efficacy of breast FNAC in patients with breast lesions compared with that of the definitive histological diagnasis. Materials and Methods: This is a hospital-based retrospective study of 112 breast FNAC samples were carried out at Cancer Institute in Medani Gezira state.  FNAC findings were correlated with data from histopathology records to determine the sensitivity and specificity of FNAC. Results: Age group of the patients ranged from 26 to 80 years with mean of 42 years. Among the study subjects (112 case), ductal carcinoma is the common hitological finding 83/88 (94%). According to the cytology, 79% were malignant, 4% were benign and 2% were suspicious. Histological correlation was done in 68 cases. The overall diagnostic accuracy of FNAC was 92.3%, with sensitivity and specificity of 89.2% and 66.5% respectively.  Conclusion: FNAC of breast is asimple, cost effective and less traumatic method for diagnosing breast cancer. It is highly sensitive and accurate, and can reduce the needs for open biopsies. It is recommended that FNAC should be used as a first line method for determining the nature of breast lumps. &nbsp

Perceptions and Expectations of Medical Students towards the Quality of Educational Services offered at A Sudanese University: How Far is the Gap?

Background: Students are the primary customers of high education service, and are becoming more aware of their consumer rights and of gaps between their expectations of service delivery and the reality of services.Objective: of this study was to investigate medical students’ perceptions and expectations of educational services quality at X University in Sudan.Methods: One hundred ninety six registered medical students in the academic year 2013- 2014, were enrolled; sample was collected through convenience sample technique. The study was conducted by the use of Modified SERVQUAL questionnaire. SPSS version 20 was used for data analysis.Results: There was a negative mean score for quality gap in all dimensions of service quality. Students perceived tangibles as quality indicators of the service quality at university, and expect universities to have modern-looking equipment, so that staff can provide efficient service to them. There was a strong student concern about teaching staff promises regarding timetables and exam schedules to be fulfilled on time, which indicated the area of most concern amongst the respondents (gap score – 1.94). A clear communication problem regarding service delivery was inferred, as students perception towards solving their problems was very low (gap score -1.91).Conclusion: students’ perceptions of services delivered by X University falls below their expectations; that indicates student’s dissatisfaction. This large gap constitutes a great challenge to the administrators and educational policy makers, who are recommended to consider students feedback as a quality indicator in the quality assurance process.Keywords: medical student, quality education, Sudan

A Conceptual Model for Blockchain-Based Agriculture Food Supply Chain System

In agriculture supply chain management, traceability is a crucial aspect to ensure food safety for increasing customer loyalty and satisfaction. Lack of quality assurance in centralized data storage makes us move towards a new approach based on a decentralized system in which transparency and quality assurance is guaranteed throughout the supply chain from producer to consumer. The current supply chain model has some disadvantages like a communication gap between the entities of the supply chain and no information about the travel history and origin of the product. The use of technology improves the communication and relation between various farmers and stakeholders. Blockchain technology acquires transparency and traceability in the supply chain, provides transaction records traceability, and enhances security for the whole supply chain. In this paper, we present a blockchain-based, fully decentralized traceability model that ensures the integrity and transparency of the system. This new model eliminated most of the disadvantages of the traditional supply chain. For the coordination of all transactions in the supply chain, we proposed a decentralized supply chain model along with a smart contract.publishedVersio

Theileria lestoquardi in Sudan is highly diverse and genetically distinct from that in Oman

Malignant ovine theileriosis is a severe tick-borne protozoan disease of sheep and other small ruminants which is widespread in sub-Saharan Africa and the Middle East. The disease is of considerable economic importance in Sudan as the export of livestock provides a major contribution to the gross domestic product of this country. Molecular surveys have demonstrated a high prevalence of sub-clinical infections of Theileria lestoquardi, the causative agent, among small ruminants. No information is currently available on the extent of genetic diversity and genetic exchange among parasites in different areas of the country. The present study used a panel of T. lestoquardi specific micro- and mini-satellite genetic markers to assess diversity of parasites in Sudan (Africa) and compared it to that of the parasite population in Oman (Asia). A moderate level of genetic diversity was observed among parasites in Sudan, similar to that previously documented among parasites in Oman. However, a higher level of mixed-genotype infection was identified in Sudanese animals compared to Omani animals, consistent with a higher rate of tick transmission. In addition, the T. lestoquardi genotypes detected in these two countries form genetically distinct groups. The results of this work highlight the need for analysis of T. lestoquardi populations in other endemic areas in the region to inform on novel approaches for controlling malignant theileriosis

Erectogenic Effects of Clerodendron capitatum

Clerodendron capitatum (Willd) (family: verbenaceae) is locally named as Gung and used traditionally to treat erectile dysfunction. Therefore, the current study was designed to investigate the erectogenic properties of C. capitatum. The relaxation effect of this plant was tested on phenylephrine precontracted rabbit corpus cavernosum smooth muscle (CCSM). The effects of C. capitatum were also examined on isolated Guinea pig atria alone, in the presence of calcium chloride (Ca2+ channel blocker), atropine (cholinergic blocker), and glibenclamide (ATP-sensitive K+ channel blocker). These effects were confirmed on isolated rabbit aortic strips. The extract, when tested colorimetrically for its inhibitory activities on phosphordiesterase-5 (PDE-5) in vitro towards p-nitrophenyl phenyl phosphate (PNPPP), was observed to induce significant dose-dependent inhibition of PDE-5, with an ID50 of 0.161 mg/ml (<.05). In conclusion, our results suggest that C. capitatum possesses a relaxant effect on CCSM, which is attributable to the inhibition of PDE-5, but not mediated by the release calcium, activation of adrenergic or cholinergic receptors, or the activation of potassium channels

Molecular identification of different Theileria and Babesia species infecting sheep in Sudan

The epidemiological aspects of sheep piroplasmosis in Sudan are poorly studied, and further investigations using sensitive and precise techniques are required. In this study, the Reverse Line Blot (RLB) hybridization assay was used to detect and simultaneously differentiate between Theileria and Babesia species. DNA was extracted from blood collected on filter paper (n=219) from apparently healthy sheep from six different geographical localities in Sudan. Results indicated that Theileria ovis (88.6%), T. separata (20.1%), T. lestoquardi (16.4%) and T. annulata (16.4%) DNA could be detected in the blood samples. Single and mixed Theileria infections were detected in 74 (33.8%) and 124 (56.6%) respectively and T. ovis being the most prevalent species in the country. T. ovis and T. separata were reported for the first time in sheep in Sudan.University of Elimam Elmahadi, Ministry of High Education and Scientific Research, Sudanhttp://www.bioone.org/loi/copaam2016Veterinary Tropical Disease

Novel deep eutectic solvent-functionalized carbon nanotubes adsorbent for mercury removal from water

Due to the interestingly tolerated physicochemical properties of deep eutectic solvents (DESs), they are currently in the process of becoming widely used in many fields of science. Herein, we present a novel Hg2+ adsorbent that is based on carbon nanotubes (CNTs) functionalized by DESs. A DES formed from tetra-n-butyl ammonium bromide (TBAB) and glycerol (Gly) was used as a functionalization agent for CNTs. This novel adsorbent was characterized using Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, XRD, FESEM, EDX, BET surface area, and Zeta potential. Later, Hg2+ adsorption conditions were optimized using response surface methodology (RSM). A pseudo-second order model accurately described the adsorption of Hg2+. The Langmuir and Freundlich isotherms models described the absorption of Hg2+ on the novel adsorbent with acceptable accuracy. The maximum adsorption capacity was found to be 177.76 mg/g

Hepatitis C virus infects and perturbs liver stem cells

Hepatitis C virus (HCV) is the leading cause of death from liver disease. How HCV infection causes lasting liver damage and increases cancer risk remains unclear. Here, we identify bipotent liver stem cells as novel targets for HCV infection, and their erroneous differentiation as the potential cause of impaired liver regeneration and cancer development. We show 3D organoids generated from liver stem cells from actively HCV-infected individuals carry replicating virus and maintain low-grade infection over months. Organoids can be infected with a primary HCV isolate. Virus-inclusive single-cell RNA sequencing uncovered transcriptional reprogramming in HCV+ cells supporting hepatocytic differentiation, cancer stem cell development, and viral replication while stem cell proliferation and interferon signaling are disrupted. Our data add a new pathogenesis mechanism—infection of liver stem cells—to the biology of HCV infection that may explain progressive liver damage and enhanced cancer risk through an altered stem cell state