Effects of fuel ratio on performance and emission of diesel-compressed natural gas (CNG) dual fuel engine

Recent research breakthrough reveals that diesel-CNG dual fuel (DDF) combustion can potentially reduce exhaust emission of internal combustion engines. However, problem arises when knock phenomenon occurs producing high carbon monoxide (CO) and hydrocarbon (HC) emission due to uncontrolled blending ratio of diesel-CNG fuel on specific engine load. This study will determine the limit of dual fuel ratio before knock occurrence while analysing performance and exhaust emission of an engine operating with diesel and DDF fuel mode. A 2.5 litre 4-cylinder direct injection common-rail diesel engine was utilised as a test platform. The modelstested were 100% Diesel, 90% DDF, 80% DDF and 70% DDF, representing diesel to CNG mass ratio of 100:0, 90:10, 80:20 and 70:30 respectively. It was found that DDF engine performance was lower compared to diesel engine at 1500 rpm engine speed. At higher engine speed, the 70% DDF showed engine performance comparable to diesel engine. However, high HC emission with knock onset and a decrease of Nitrogen Oxide (NOX) emission were recorded. This study suggests the preferred limit of dual fuel ratio should not be lower than 70% DDF which will be able to operate at high engine speed without the occurrence of knock and poor exhaust emission

Protective Role of Commiphora molmol Extract against Liver and Kidney Toxicity Induced by Carbon Tetrachloride in Mice

Purpose: To explore the protective role of Mirazid® (MRZ), a mixture extracted from Commiphora molmol Engler (Burseraceae), against toxicity induced by carbon tetrachloride (CCl4).Method: Forty male Swiss albino mice were divided into 4 groups. Group 1 was control and included mice which were injected with normal saline; group 2 was positive control and included mice that had no treatment for 17 days followed by intraperitoneal (i.p) injection of 200 mg/kg/day MRZ for 7 consecutive days; groups 3 and 4 included mice which were injected intraperitoneally (i.p) with 0.8 mL/kg of 30 % CCl4 on days 1, 4, 7, 10, 13 and 16; animals of group 4 were then post treated with 200 mg/kg/day MRZ for 7 consecutive days. At the end of the experiment, the mice were euthanized and subjected to a complete necropsy. Hematological and biochemical parameters were assessed. To estimate the histological changes, liver and kidney sections were exposed to microscopic examination.Results: The levels of leucocytes, granulocytes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, urea, creatinine, cholesterol and triglycerides showed a significant increase (p ˂ 0.05) while the levels of lymphocytes, platelets counts, total protein and albumin showed a significant decrease (p ˂ 0.05) in CCl4-injected mice when compared with the control groups, respectively. Histological observation of the liver and kidney showed necrotic areas with cellular infiltration and atrophied renal glomerulei with degenerated renal tubule lining, respectively. Mice that were treated with MRZ after CCl4 showed that the levels of lymphocytes, ALT, AST and albumin had insignificant change (p > 0.05) compared with the control groups, respectively.Conclusion: MRZ partially ameliorates the toxicity induced by CCl4 in mice by improving ALT, AST and protein profiles. Therefore, further investigations are required to figure out its antioxidant potential in order to ascertain if it can be used as an antioxidant drug.Keywords: Carbon tetrachloride, Mirazid®, Toxicity, Biochemical, Heamatological, Lipid profile, Liver and kidney function

Prevalence and characterization of plasmid-mediated quinolone resistance genes in Proteus species isolated from different patients

Proteus spp. are widely distributed opportunistic pathogens that can cause various human infections. A total of 361 clinical specimens were obtained from patients who were attending to different hospitals in El-Minia governorate, Egypt. Approximately 23 % of the samples belong to Proteus spp. isolates which were obtained from various clinical sources. After biochemical identification, 42.1 % of isolates were found to belong to Proteus vulgaris and 57.8 % to P. mirabilis. The urine samples collected from catheterized patients represented 32.6 % of all the clinical specimens, and the majority of the recorded isolates were Proteus spp. The antibacterial sensitivity of the Proteus spp. was examined using 16 different antibiotics from various families. The most effective antibiotics were Amikacin; Levofloxacin, and Meropenem, recording 68.6 %, 66.2 %, and 62.2 % of the isolates sensitivity to each of these antibiotics, respectively. Using the ureR-based PCR, 48 % of the isolates were identified as P. mirabilis. Moreover, the Qnr genes (i.e., qnrA, qnrB, qnrS, qnrD, and qnrC) and the aac (6')-Ib-cr gene had been identified in 40 % of P. mirabilis isolates. The aims of the study were to investigate the prevalence of Proteus spp. in El-Minia, Egypt; determine the antibacterial susceptibility pattern of these isolates, and characterize the PMQR genes in Proteus spp. Quinolone resistance in P. mirabilis isolates might have been brought on by mechanisms other than qnr and aac (6')-Ib genes. Finally, since Proteus spp. are widespread in the environment; healthcare facilities must uphold stringent sanitation standards to reduce the incidence of the nosocomial infections

Hyperthyroidism as a reversible cause of right ventricular overload and congestive heart failure

We describe a case of severe congestive heart failure and right ventricular overload associated with overt hyperthyroidism, completely reversed with antithyroid therapy in a few week. It represents a very unusual presentation of overt hyperthyroidism because of the severity of right heart failure. The impressive right ventricular volume overload made mandatory to perform transesophageal echo and angio-TC examination to exclude the coexistence of ASD or anomalous pulmonary venous return. Only a few cases of reversible right heart failure, with or without pulmonary hypertension, have been reported worldwide. In our case the most striking feature has been the normalization of the cardiovascular findings after six weeks of tiamazole therapy

Burden of visceral leishmaniasis in villages of eastern gedaref state, Sudan: an exhaustive cross-sectional survey.

Since December 2009, Médecins Sans Frontières has diagnosed and treated patients with visceral leishmaniasis (VL) in Tabarak Allah Hospital, eastern Gedaref State, one of the main endemic foci of VL in Sudan. A survey was conducted to estimate the VL incidence in villages around Tabarak Allah

Comparison of fiber Bragg grating based on SMF and MMF over temperature sensitivity

We have successfully fabricated and demonstrated a simple, cost-effective and easy to use of fiber Bragg grating (FBG) based on single mode, and multimode fiber which have been employed for temperature monitoring. The study purposely compared the performance of two types of FBGs; single mode FBG (SM-FBG) and multimode FBG (MM-FBG). The FBGs sensor is fabricated by phase mask technique which being exposed to ArF excimer laser with 20 mm uniform grating length and 99% reflectivity. The proposed FBG is studied for temperature monitoring starting at room temperature until 120 °C, and the configurations with SM-FBG and MM-FBG achieved a sensitivity of 10.9 pm/°C and 13.23 pm/°C, respectively whereas linear response correlation coefficient of 0.98229 and 0.99929. These show the MM-FBG has better sensitivity to be used in sensor applications

The effect of FBG grating lengths for temperature sensing

In this work, we have successfully fabricated the fiber Bragg grating (FBG) with 1 cm and 3 cm grating length, respectively. The different grating length fabricated by adjusting the slit aperture in order to control UV light transmission while inscribing on the single mode fiber. Then the FBG was demonstrated through different grating length over temperature sensor to determine the differences for temperature sensing. The range for temperature The measured sensitivity of 1 cm and 3 cm grating length is 0.0103 nm/°C and 0.0132 nm/°C respectively at the same value of applied temperature. As a results, the shorter grating length, 1 cm has higher sensitivity response compared to 3 cm grating length over temperature sensing

Search for Doubly-Charged Higgs Boson Production at HERA

A search for the single production of doubly-charged Higgs bosons H^{\pm \pm} in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one of them being an electron. The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3, masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl

Prevalence of Post COVID-19 Condition among Healthcare Workers: Self-Reported Online Survey in Four African Countries, December 2021–January 2022

The impact of Post COVID-19 Condition (PCC) is ongoing despite the declaration that the 2019 COVID-19 pandemic has ended. In this study, we explore the prevalence of PCC among healthcare workers (HCWs) in four African Countries and its influence on their professional performance. This study was conducted as an online cross-sectional survey of healthcare workers from four African countries (Cameroon, Egypt, Nigeria, and Somalia) between the 20th of December 2021 to 12th of January 2022. We determined the prevalence of PCC based on the WHO case definition and assessed variables associated with a higher prevalence of PCC in these countries using univariable and multivariable logistic regression analyses. A total of 706 HCWs from four African countries were included in this survey. Most of the HCWs were aged between 18–34 years (75.8%, n = 535). Our findings showed that 19.5% (n = 138) of the HCWs had tested positive for SARS-CoV-2. However, 8.4% (n = 59) were symptomatic for COVID-19 but tested negative or were never tested. Two-thirds of the HCWs (66.4%, n = 469) have received a COVID-19 vaccine and 80.6% (n = 378) of those vaccinated had been fully vaccinated. The self-reported awareness rate of PCC among the HCWs was 16.1% (n = 114/706) whereas the awareness rate of PCC among COVID-19-positive HCWs was 55.3% (n = 109/197). The prevalence of PCC among HCWs was 58.8% (n = 116). These changes include the self-reported symptoms of PCC which included headache (58.4%, n = 115), fatigue (58.8%, n = 116), and muscle pain (39.6%, n = 78). Similarly, 30% (n = 59) and 20.8% (n = 41) of the HCWs reported the loss of smell and loss of taste long after their COVID-19 infection, respectively. Some HCWs (42%, n = 83) believed that their work performance has been affected by their ongoing symptoms of PCC. There was no significant difference in the prevalence of PCC among the vaccinated and unvaccinated HCWs (p > 0.05). Of the socio-demographic variables, age (older HCWs between 45–54 years; OR:1.7; 95% CI: 1.06, 10.59; p = 0.001) and location (Egypt; OR:14.57; 95% CI: 2.62, 26.76; p = 0.001) were more likely to have experienced PCC than other age groups and countries respectively. The study revealed a low prevalence of PCC among the surveyed HCWs. In addition, it observed the need for adequate medical and psychological support to HCWs with PCC and improved mass advocacy campaigns on PCC