572 research outputs found
Time-Fractional KdV Equation for the plasma in auroral zone using Variational Methods
The reductive perturbation method has been employed to derive the Korteweg-de
Vries (KdV) equation for small but finite amplitude electrostatic waves. The
Lagrangian of the time fractional KdV equation is used in similar form to the
Lagrangian of the regular KdV equation. The variation of the functional of this
Lagrangian leads to the Euler-Lagrange equation that leads to the time
fractional KdV equation. The Riemann-Liouvulle definition of the fractional
derivative is used to describe the time fractional operator in the fractional
KdV equation. The variational-iteration method given by He is used to solve the
derived time fractional KdV equation. The calculations of the solution with
initial condition A0*sech(cx)^2 are carried out. Numerical studies have been
made using plasma parameters close to those values corresponding to the dayside
auroral zone. The effects of the time fractional parameter on the electrostatic
solitary structures are presented.Comment: 1 tex file + 5 eps figure
Enhancement the Thermal Stability and the Mechanical Properties of Acrylonitrile-Butadiene Copolymer by Grafting Antioxidant
Monomeric antioxidants are widely used as effective antioxidants to protect polymers against thermal oxidation. Low molecular weight antioxidants are easily lost from polymer through migration, evaporation, and extraction. Physical loss of antioxidants is considered to be major concern in the environmental issues and safety regulation as well as long life time of polymers. The grafting copolymerization of natural rubber and o-aminophenol was carried out by using two-roll mill machine. The prepared natural rubber-graft-o-Aminophenol, NR-graft-o-AP, was analysed by using Infrared and 1H-NMR Spectroscopy techniques. The thermal stability, mechanical properties, and ultrasonic attenuation coefficient were evaluated for NBR vulcanizates containing the commercial antioxidant, N-phenyl--naphthylamine (PBN), the prepared grafted antioxidant, NR-graft-o-AP, and the control vulcanizate. Results of the thermal stability showed that the prepared NR-graft-o-AP can protect NBR vulcanizate against thermal treatment much better than the commercial antioxidant, PBN, and control mix, respectively. The prepared grafted antioxidant improves the mechanical properties of NBR vulcanizate
Quality Assessment of Borehole Water in-Terms of Selected Physicochemical Parameters in Maiduguri Urban Areas, Borno State, Nigeria
In Nigeria, over 120 million peoples use boreholes as their main source of drinking water and in-view of the increasing volume of solid waste materials in Maiduguri, it has become exigencies to evaluate the quality of borehole waters in the city. The objective of this paper is therefore to evaluate some physicochemical characteristic of borehole water samples in Maiduguri urban areas Borno State, Nigeria using standard methods. Result obtained revealed that the pH of all the water samples was within the range of 6.5 to 8.5 as recommended limit by World Health Organization (WHO). Except for the pH of borehole water at Bulumkutu ward which is acidic (6.2). The pHs of all the water from the three wards were alkaline. The total dissolved solid and the electrical conductivity of water samples from the three wards fall within the limit of WHO, except water samples from Ngarannam (1100 mg/l) and (2220 uS/cm). The concentration of major ions (Na, Mg and K) fall far below the WHO recommended limit and thus the water can said to be excellent in terms of these elements. Except for Cl ion (262 mg/g) at borehole water in Gwange ward fall above the permissible limit by WHO. The study recommends performing regular testing of different water sources within the study area to ensure that commensurate attention given is maintaining a healthy population
Depression amongst healthcare workers in Maiduguri, north-eastern Nigeria
Objective: Very few studies reported the high prevalence of emotional reactions amongst healthcare workers, in sub-Saharan Africa. This study aimed to assess the prevalence of depression among health care workers in two tertiary health institutions in Maiduguri, north-Eastern Nigeria.Methods: In this comparative, cross-sectional study, we used a stratified sampling technique to recruit 370 healthcare workers (clinical and non-clinical staff) from university teaching hospital, and Federal Neuro-psychiatric Hospital, Maiduguri, Borno State, north-east Nigeria. The participants completed a semi-structured socio-demographic questionnaire and Beck Depression Inventory (BDI-II).Results: Twenty (10.7%) and 14 (7.6%) clinical and non-clinical health care workers, respectively had depression (÷2 = 1.096, df = 1, ñ = 0.295). The prevalence of depression in males and females were 7.8% and 26.9%, respectively. Gender had a significant association with depression (÷2 = 3.427, df = 1, ñ =0.043).Conclusion: For an effective healthcare delivery service, the psychological well-being of hospital workers must be improved. Hospital workers require skills on stress management techniques.Keywords: Depression, healthcare workers, Maiduguri, Nigeri
Presence of Human Herpes Virus 6 (HHV6) in pediatric lymphomas: impact on clinical course and association with cytomegalovirus infection
<p>Abstract</p> <p>Background</p> <p>Activation of herpes virus 6 (HHV6) has seen in Hodgkin's and non-Hodgkin's Lymphoma (HL&NHL) as a result of lymphoma associated immunosuppression. Multiple studies have suggested an association between both HHV6 and cytomegalovirus CMV for development of CMV disease affecting the pathogenesis of lymphoma. Therefore, this study investigated the frequency of HHV6, its impact on clinical manifestations of lymphoma and its possible association with risk for development of CMV infection in pediatric lymphoma patients.</p> <p>Methods</p> <p>Presence of HHV6 DNA and CMV DNA was investigated by PCR assay in both WBC's and plasma samples from 50 patients diagnosed with HL or NHL. CMV antibody titer was also determined in sera obtained from each patient. Twenty apparently healthy siblings were used as a control group.</p> <p>Results</p> <p>In a study group of 50 patients diagnosed with HL or NHL, 23/50 (46%) were found to be positive for herpes virus DNA (HHV6 or CMV) in WBC's or plasma by PCR assay and this was significantly higher than its presence in the pediatric control group 2/20 (10%) (p = 0.005). Ten out of these 23 (43%) were found to have active CMV infection. Fifty six percent of patients with CMV infection were found among NHL cases with B- subtype. The presence of both herpes viruses DNA was significantly associated with more frequent episodes of febrile neutropenia (median 3 episodes), absolute neutrophil count (< 0.8), lymphocytes (< 0.5), and low hemoglobin level (< 9.1), (p < 0.05).</p> <p>Conclusion</p> <p>The presence of HHV6 can be considered as a predicting indicator of cellular immunosuppression preceding the onset of CMV infection which may result in a severe outcome among pediatric lymphoma patients.</p
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