DESIGN, FABRICATION AND EVALUATION OF DIGITAL TILT TEST DEVICE

Due to the high and fluctuating exchange rate, obtaining devices and equipment for practical demonstration of theoretical contents of engineering and applied science courses in developing countries is becoming a herculean task. To sustain the practical aspect of these courses, some of the devices have to be locally manufactured. In this study, a digital tilt test device for determining the basic friction angle and joint roughness coefficient (JRC) of rock samples was designed and fabricated using majorly local materials. Comparing the device's results with those obtained from the Profilometer, there was a satisfactory correlation between the two results. The device is much cheaper to manufacture locally than the imported onesTherefore, it is recommended that the device be used for estimating the friction angle and JRC of rock samples. Similar devices with simple mechanisms should be manufactured locally in higher institutions to reduce dependency on foreign devices, which are expensive

Comparative Study of Maximum Power Point Tracking with a Modified DC DC Converter

Maximum power points are used to find the voltages and currents at which a photovoltaic (PV) panel should operate to obtain maximum power. In order to deliver highest power, an efficient DC DC converter and a reliable tracking algorithm are used. There is also the need to continuously find the maximum power under any environmental conditions at all times. This research is intended to study a comparative performance of maximum power point (MPP) which is presented under uniform irradiance condition. The algorithm employed is an improved cuckoo search algorithm and the DC-DC Converter( switched mode power supply) has been modified by including a synchronous rectifier connected to a load, the performance of the system is validated using MATLAB/Simulink and practical implementation for this work. A comparison of the MATLAB Simulation with the practical implementation of MPP is presented using maximum power and percentage tracking efficiency as performance metric. From the MATLAB results obtained, maximum extracted power is 26.81W and the hardware implementation gives a maximum power of 28.71W. Tracking efficiency improves by 6.62%. The results show the practical MPP gives a better maximum power, which consequently improves the Photovoltaic systems efficiency and conversely mitigates the power consumption and the cost of the system than the simulation result obtained in MATLAB

Hepatitis B and C: An assessment of risk exposure and prevalence among preclinical medical students in northwestern Nigeria

Background: The risk of transmission of hepatitis B and C (HBV and HCV) infection is of particular concern among medical students training in high endemic regions. In this study,we investigated the risk and prevalence of hepatitis B and C viruses among preclinical medical students in a government-owned medical school in northwestern Nigeria.Methods: We employed a cross-sectional studytargeting the whole population of preclinical medical students of Kaduna State University, Kaduna State northwestern Nigeria. Data were collected usinga self-administered, semi-structured questionnaire and blood testing for HBsAg and HCV antibodies using rapid screening kits.Data were analyzed using SPSS version 22.Results: A total of 133 students participated, and 79.7% of them had a previous risk exposure to injuries by sharps. The seroprevalence for HBV and HCV was 0.8% for both infections. Complete HBV vaccination uptake (3 doses)before enrolment in medical school was 18.8%. The knowledge that HBV infection is preventable was a significant determinant for the previous testing for hepatitis B and C.Conclusion: Risk exposure to injuries by sharps was high in preclinical students. But their seroprevalence for both hepatitis B and C were low. Keywords: Hepatitis B and C viruses;prevalence; medical students;sharp injurie

A novel double chamber rotary sleeve air compressor -part II: friction losses model

This paper presents the friction loss model of a novel double chamber rotary sleeve air compressor (DCRSC) concept. The compressor mechanism is similar to that of rotary compressor whereby the novelty transpires in the instalment of two rotating sleeves and a secured vane that has one end fixed to an outer sleeve and the other end to a rotor, respectively. This Part II of the paper series presents the friction losses analysis of the compressor. Thermodynamic and leakage losses models were respectively presented in Part I and Part III of this paper series. The primary aim of this paper is to formulate and analyse the friction loss model at the radial and axial contact regions of DCRSC at different rotational speed. The variations of the mechanical power and efficiency were evaluated based on the adiabatic, polytropic and isothermal thermodynamic principles as illustrated in Part I of this paper series. Considering the design simplicity of cylindrical shaped components, at maximum rotational speed of 1500 rpm, the DCRSC mechanical efficiencies are 72.43%, 66.2% and 59% when air undergoes adiabatic, polytropic and isothermal compression process, respectively. it is believed that the DCRSC is well suited for compressed air systems and air-conditioning applications

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p&lt;0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p&lt;0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe