Biodiesel production using solid metal oxide catalysts

Biodiesel production is worthy of continued study and optimization of production procedures due to its environmentally beneficial attributes and its renewable nature. Heterogeneous transesterification is considered to be a green process. The process requires neither catalyst recovery nor aqueous treatment steps and very high yields of methyl esters can be obtained, close to the theoretical value. However, heterogeneously catalyzed transesterification generally requires more severe operating conditions, and the performance of heterogeneous catalysts is generally lower than that of the commonly used homogeneous catalysts. Heterogeneous catalysis for biodiesel production has been extensively investigated in the last few years. Many metal oxides have been studied for the transesterification process of oils; these include alkali earth metal oxides, transition metal oxides, mixed metal oxides and supported metal oxides. The use of solid metal oxides as catalysts in oil transesterification is well established, accordingly, researchers' attempts are now focused on how to attain the highest catalyst activity. Catalyst activity is a function of its specific surface area, base strength and base site concentration. High specific surface area, strong base strength and high concentration of base sites are characteristics of an active transesterification catalyst. This review provides a brief overview of the different metal oxides frequently used in the process of transesterification of oils for the production of biodiesel with special reference to the various methods of catalyst preparation and catalyst characterization. Reaction conditions and catalyst leaching analysis are also highlighted. Finally, concluding remarks regarding catalyst selection and catalyst preparation steps are provided

Different techniques for the production of biodiesel from waste vegetable oil

The production of biodiesel from waste vegetable oil offers a triple-facet solution: economic, environmental and waste management. The new process technologies developed during the last years made it possible to produce biodiesel from recycled frying oils comparable in quality to that of virgin vegetable oil biodiesel with an added attractive advantage of being lower in price. Thus, biodiesel produced from recycled frying oils has the same possibilities to be utilized. While transesterification is well-established and becoming increasingly important, there remains considerable inefficiencies in existing transesterification processes. There is an imperative need to improve the existing biodiesel production methods from both economic and environmental viewpoints and to investigate alternative and innovative production processes. This study highlights the main changes occurring in the oil during frying in order to identify the characteristics of oil after frying and the anticipated effects of the products formed in the frying process on biodiesel quality and attempts to review the different techniques used in the production of biodiesel from recycled oils, stressing the advantages and limitations of each technique and the optimization conditions for each process. The emerging technologies which can be utilized in this field are also investigated. The quality of biodiesel produced from waste vegetable oil in previous studies is also reviewed and the performance of engines fueled with this biodiesel and the characteristics of the exhaust emissions resulting from it are highlighted. The overarching goal is to stimulate further activities in the field

Correlation between the chemical structure of biodiesel and its physical properties

Biodiesel is a renewable, biodegradable, environmentally benign, energy efficient, substitution fuel which can fulfill energy security needs without sacrificing engine's operational performance. Thus it provides a feasible solution to the twin crises of fossil fuel depletion and environmental degradation. The properties of the various individual fatty esters that comprise biodiesel determine the overall properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Better understanding of the structure-physical property relationships in fatty acid esters is of particular importance when choosing vegetable oils that will give the desired biodiesel quality. By having accurate knowledge of the influence of the molecular structure on the properties determined, the composition of the oils and the alcohol used can both be selected to give the optimal performance. In this paper the relationship between the chemical structure and physical properties of vegetable oil esters is reviewed and engineering fatty acid profiles to optimize biodiesel fuel characteristics is highlighted

Medicalization of female genital cutting in Egypt

The medicalization of female genital cutting [FGC] has been increasing. This cross-sectional study estimated the determinants of the practice of FGC among Egyptian physicians. Responses from 193 physicians showed that while 88% of them knew at least one adverse physical or sexual consequence, 18% approved of it, mostly as a religious observation [82%]. Almost one-fifth [19%] of physicians practised FGC, mostly due to conviction [51%] or for profit [30%]. A negative correlation was found between knowledge of the adverse consequences of FGC and both approval and practice. Cultural influences were the highest determinant [81%] followed by lack of knowledge [35%]

Production optimization and quality assessment of biodiesel from waste vegetable oil

Biodiesel production is worthy of continued study and optimization of production procedures because of its environmentally beneficial attributes and its renewable nature. In Egypt, millions L of oil used for frying foods are discarded each year into sewage systems. Thus, it adds to the cost of treating effluent or pollutes waterways. This study is intended to consider aspects related to the feasibility of the production of biodiesel from waste/recycled oils in an attempt to help reduce the cost of biodiesel and reduce waste and pollution coming from waste oils. The variables affecting the yield and characteristics of the biodiesel produced from used frying oil were studied, the achieved results were analyzed and a set of recommendations was proposed. From the obtained results, the best yield percentage was obtained using a methanol/oil molar ratio of 6:1, potassium hydroxide as catalyst [1%] and 65 °C temperature for one hour. The yield percentage obtained from waste vegetable oil was comparable to that obtained from neat vegetable oil which reached 96.15% under optimum conditions. From the results it was clear that the produced biodiesel fuel, whether from neat vegetable oil or waste vegetable oil, was within the recommended standards of biodiesel fuel

Studies on the effects of chromium supplementation on the metabolic response to exercise

Chromium is one of the essential dietary trace elements that an important role in regulating whole body metabolism and energy utilization. However, there is a strong argument about chromium supplementation during exercise training programs, as some authors recommend it and others consider it illegal. Therefore, this work was planned to assess the metabolic responses to exercise training program in conjunction with chromium supplementation. Four rat groups were studied; rats subjected to swim exercise 2 hours/day for 2 weeks, rats supplemented with chromium picolinate in a dose of 90 micro g/kg body weight/day by gavage for 2 weeks and rats exposed to both regimens as well as their control non-exercised non-supplemented rats. Results of the present study revealed improvement in glucose tolerance with insignificant changes in serum insulin concentrations and a remarkable hypolipidemic responses in the three studied rat groups compared to the control. Unexpectedly the metabolic responses of the combination of chromium and exercise training did not exceed those obtained either chromium supplementation alone or exercise alone. Such non-additive effect could be ascribed to the common pathway shared by both chromium and exercise to exert their actions; and either chromium or exercise could, on its own, achieve the maximal response that cannot be further increased by their combination. The beneficial effects of chromium supplementation on increasing insulin sensitivity and improving blood lipid profile makes it an effective agent in treating non-insulin dependent diabetes and arteriosclerosis. Also, chromium has favorable effects in sparing protein use during exercise, decreasing lactate production with conservation of high glycogen content that enables prolongation of strenuous muscular exercise and much delaying the exhaustion point. In conclusion, it is evident from this study that chromium is instrumental in mediating metabolic effects of exercise and its role, in this respect, is physiological not pharmacological. Therefore, it is wrong to deal with chromium as one of the ergogenic substances that considered illegal to use with exercise

Chromium, the natural lipid-modulating therapy, protects the rat myocardium against ischemic-reperfusion hazards

This study was carried out on 20 male albino rats weighing 200-250 grams each. They were divided into 2 groups: Group I [n = 10], used as control; Group II [n = 10], chromium supplemented rats at a dose of 20 micro g/ rat/day for 12 weeks. After that, blood samples were collected for estimation of serum triglycerides [TG], total cholesterol [TC], high density lipoprotein-cholesterol [HDL-C] as well as fasting glucose and insulin levels. This was followed by ischemia-reperfusion of isolated hearts. After 30 minutes of reperfusion, the hearts were sent for histopathological examination, LDL-cholesterol [LDL-C] and HDL/total cholesterol ratio were also calculated. The results of this study showed that chromium supplementation induced significant reduction in the levels of serum glucose, insulin, TG, LDL-C and TC accompanied by a significant increase in HDL-C and HDL-C/TC ratio. Chromium supplemented hearts, also showed better recovery of myocardial activity at different periods of reperfusion compared to control hearts in the form of a significant increase in heart rate [HR], peak tension [PT] and myocardial flow rate [MFR] as well as an insignificant reduction in time to peak tension [TPT] and half relaxation time [1/2RT]. Histopathological examination of hearts showed a clear picture of ischemia in control hearts compared to chromium supplemented hearts. We can conclude that chromium supplementation can protect the rat myocardium against ischemic-reperfusion hazards and this may be due to promoting the healthy blood lipid level and reducing fasting insulin levels which may reflect enhancement of tissue sensitivity to insulin

Early post-operative fever following tonsillectomy: a possible cause and management

Tonsillectomy/adenotonsillectomy is routinely performed in the practice of otolaryngology, however, the aetiology of the low-grade early post-operative fever [1-3 days] remains todate obscure. Bacteraemia during surgery, anaesthetic agents and the inflammatory response to tissue injury have been speculated but without a conclusive evidence. In the current study, we looked into the inhalation and ingestion of blood during the surgical procedure as an aetiological factor. A prospective study in 350 children undergoing tonsillectomies or adenotonsillectomies was performed during two-year duration from January 2003 to January 2005 at Misr University. In all cases, the amount of blood inhaled was assessed immediately following the operation by passing a small rigid bronchoscope and aspirating all blood inhaled during surgery after gaining the parents consent, while faecal occult blood looked for the ingested blood in all cases. It was found that a few milliliters [1-5 ml] of blood do actually find their way to the trachea especially if non-cuffed endotracheal tube is used. On the other hand, the stool of the patients who head early post-operative fever following tonsillectomy [35 cases out of 350 i.e.10%], showed a significant amount of occult red blood cells in 31 patients out of the 35 i.e.88.5%. Moreover a 3 days course of 660 mg/day of nifuroxazide [Antinal] the intestinal antiseptic drug, in three divided doses was effective in the fever relief. Our results indicate that ingested blood during surgery may activate the intestinal pathogenic organisms with subsequent gastroenteritic reaction resulting into this low to moderate grade post-operative fever, despite the fact that there was no change in bowel motion. This highlights the importance of packing the pharynx to minimize the amount of blood ingested during surgery, and the use of antinal to tackle this post-operative fever if existed

Practice and awareness of health risk behaviour among Egyptian university students

Health risk behaviour contributes markedly to today's major killers. A descriptive cross-sectional study was conducted to assess current awareness and practice of health risk behaviour among Egyptian university students. Only 121 students [18%] were practising risky behaviour. Tobacco use, alcohol and drugs use and risky sexual behaviour were positively correlated. Multiple regression analysis revealed that the main determinants of risky behaviour were being a male, of older age, having a high allowance and having no attention to danger. About 30% of students lacked adequate knowledge on AIDS. Most of those who had sexual relationships did not use contraceptives or any method of protection from sexually transmitted infection. Main sources of knowledge were the media [38%] then peers [30%]

Mechanisms of nuclear DNA damage in mature sperm from infertile men

Mechanisms of nuclear DNA damage in human spermatozoa are poorly understood. High levels of apoptosis were detected in spermatozoa from infertile men. The contribution of apoptosis and reactive oxygen species [ROS] in nuclear DNA damage of spermatozoa is not clear. The aim of this study was to elucidate the correlation between levels of apoptosis and ROS with percentage DNA damage in a group of infertile patients and normal donors. Our study included a randomly selected group of infertile men [n = 28] attending our fertility clinic for a history of infertility of more than one year. Semen samples were obtained after 2 to 3 days of sexual abstinence and were examined according to World health organization [WHO] guidelines to determine sperm concentration, motility and morphology. Samples from 22 normal donors with normal standard semen parameters were included as a control. Histologic features of apoptosis were studied using electron microscopy. Levels of apoptosis were detected using Annexin-V staining assay that detects externalization of phosphatidylserine to the outer surface of the plasma membrane of apoptotic spermatozoa. Propidium iodide stain was used to exclude necrotic spermatozoa. The percent apoptosis and necrosis were determined by epifluorescent microscopy. Two-hundred spermatozoa were randomly assessed and classified as normal [negative annexin- V and PI], apoptotic [positive annexin- V and negative PI] and necrotic [positive annexin- V and PI]. Levels of ROS were determined using a chemiluminescence assay and the results expressed as X 106 counted photons per minute [cpm] / 20 X 10[6] spermatozoa/mL. Sperm nuclear DNA damage was assessed by sperm chromatin structure assay [SCSA] to determine the percentage of cells outside the main population [%DFI] with abnormal chromatin structure. The percent apoptosis in spermatozoa from normal donors [6 +/- 2.2] were significantly lower than in patients [11.9 +/- 5.4] [P <0.001]. No significant difference was observed in percent apoptosis in patients with abnormal sperm parameters versus those with normal sperm parameters [P = 0.67]. The percent necrosis was significantly higher in the patients [54.2 +/- 13.6] versus donors [37,0 +/- 13.6] [P < 0.001]. A significant negative correlation was observed between apoptosis and sperm motility [r = -0.34, P = 0.04]. The correlation of apoptosis with sperm concentration and% normal sperm forms did not reach the standard significance [p = 0.07]. Levels of apoptosis were significantly correlated with levels of ROS [r = 0.3, P = 0.02]. A highly significant positive correlation has been demonstrated between levels of apoptosis and%DFI [r = 0.4, P = 0.02], Mean DFI [r = 0.5, P = 0.004], and SO DPI [r = 0.5, P = 0.002]. The range of% DFI was from 13.2% to 59% while that of percent apoptosis was from 1.5 to 25.5%. Our results indicate a significant correlation between levels of apoptosis, ROS and DNA damage in human spermatozoa. We conclude that apoptosis may play a significant role in DNA damage in human spermatozoa. However, apoptosis alone is not responsible for all DNA damage that could be encountered in spermatozoa. Other implicated factors such as ROS are possibly directly involved

Plasma concentrations of antioxidant vitamins and sellenium in relation to coronary heart disease

The relation between risk of coronary heart disease [CHD] and the plasma concentrations of vitamins C, E, carotene and selenium were examined in a case-control study of 100 cases of CHD chosen from the Outpatient Clinic of Menoufiya University Hospital, identified by chest pain questionnaire for angina and possible myocardial infarction and confirmed clinically and by electrocardiogram [ECG] and exercise test. Another 100 subjects matched with cases for age and socioeconomic standard who gave negative replies on the same questionnaire were selected as a control group, Each individual [case and control] was subjected to thorough clinical examination and laboratory investigations including estimation of total serum cholesterol, high density lipoprotein [HDL] cholesterol, plasma vitamins C, E, beta-carotene and selenium. The results of this study showed that plasma concentrations of vitamins C, E, carotene and selenium were significantly negatively related to the risk of CHD [P<0.05]. The significant negative relation between CHD and low plasma carotene and that with plasma vitamin C disappeared alter adjustment for smoking as it was a confounding factor. Vitamin E remained independently and negatively related to the risk of CHD after adjustment for age, smoking habit, blood pressure, lipids and relative weight. The adjusted odds ratio for CHD between the lowest and highest quartiles of vitamin E concentration was 3,7 [95% confidence interval 1 - 12] [p < 0.05]. The study recommend doing further intervention trials with vitamin supplements, and that high risk group for CHD may benefit from eating proper diet rich in natural antioxidant vitamins and selenium, i.e. vegetable and fruits and to substitute animal fat by vitamin E rich oil. Smoking cessation must be obligatory together with beta-carotene and vitamin C supplementation

Device associated nosocomial infection: a surveillance in an intensive care unit

This study was carried out in The Intensive Care Unit [ICU] at Menoufiya University Hospital from January 1997 to April 1998 to study the device-associated infection rate as an extrinsic risk factor for nosocomial infection in ICU and to compare this rate with infection rate based on patient admission and patient days in the unit. All intensive care patients were surveyed daily and all cases were examined clinically and with laboratory investigations including sputum, blood and urine cultures in the clinical pathology laboratory of the unit. Data were recorded on the National Nosocomial Infection Surveillance [NNIS] component form. The results revealed that the patient admission infection rate was 16.5% [140 cases out of 870 patients]. When the patient days were used as denominator, the infection rate was 46.35/1000 patient days. On the other hand, when device days were used as denominator, the device-associated infection rate was 31.63/1000 device days. These rates vary by type of patient in ICU and type of device utilized, the surgical ICU patients [SICU] had significantly higher pneumonia rate compared to medical ICU [MICU] [91.8 versus 54.7/1000 ventilator days, p <0.05]. Also, central intravenous-associated bacteremia rate was significantly higher in SICU compared to MICU [33.64 versus 12.93/1000 intravenous catheter days, p<0.05]. While urinary tract infection rate was significantly higher among patients in MICU compared to surgical one [32.18 versus 19.5/1000 urinary catheter days, p <0.001], which may be attributed to the prophylactic use of antibiotics among surgical patients. As regard sputum, blood, urine cultures. Gram-negative bacteria were found to be the most common organism recovered from ventilator-associated pneumonia, central intravenous catheter-associated bacteremia and catheter-related urinary tract infection [54.5%, 54.2%, 47.9% respectively]. It was found that perfect and effective hand washing significantly reduced catheter-associated intravenous bacteremia from 26.6 to 8.2/1000 catheter days and urinary tract infection rate from 25.3 to 10/1000 catheter days. So, we recommend urgent establishment of nosocomial infection control committee in Menoufiya University Hospital and more emphasis on the effective technique of hand washing as it is proved to be the simplest measure in controlling device-associated nosocomial infection in ICU. In the meantime, sterilization of equipments should be stressed with every step and each manipulation

Occupational stress and coping among physicians at Menoufiya university hospital

A cross sectional study was carried out among physicians at Menoufiya University Hospital during the period from January 1995 to November 1997 to study the relationship between physicians' mental health and their job stress, satisfaction, and coping. A questionnaire booklet was distributed to all physicians in different disciplines of medicine; psychiatric morbidity was estimated using a 12-item general health questionnaire. The three components of burnout -emotional exhaustion, depersonalization and low personal accomplishment were assessed using Maslach Burnout Inventory and coping assessed with Coping Strategy Scale [CSS]. Job stress and satisfaction were measured using study-specific questions. Two hundred and forty-eight questionnaires were returned with a response rate of 91.9%. Sixty three percent of the participants were males [mean age = 38 +/- 5 years], and 37% were females [mean age = 32 +/- 4.8 years]. The commonest source of stress was night calls [83.8%], followed by feeling overloaded and its effect on home life [73.0%] and the least was worrying about patients complaining against him [25.0%].The estimated psychiatric morbidity was 21.8% with a significantly higher value among group I [junior physicians; 26.7%] compared to group II [seniors; 14.7%] [P<0.05]. Also, group I reported a significantly higher level of burnout in terms of emotional exlaustion 23.3%, depersonalization 24% and low personal accomplishment [21.9%] compared to 12.7%, 13.7% and 11.8% among group II, respectively Global job stress was significantly associated with psychiatric morbidity, emotional exhaustion, high depersonalization [OR 21.6, 23.5, 22.4 respectively], while global job satisfaction was positively related to high personal accomplishment [OR 17.33] and inversely related to high emotional exhaustion [OR 15.3] and high depersonalization [OR 16.9] and estimated psychiatric morbidity [OR 19.5]. Burnout and psychiatric morbidity was more prevalent among physicians who felt insufficiently trained in communication and management skills, it was also associated with low satisfaction in three domains: relationship with patients' relatives and staffs; professional status/esteem and intellectual stimulation. As regard the role of coping strategy in mitigating the negative effect of work stress, if was found that physicians who adapted to work stress with high job satisfaction were more inclined to adapt approach coping methods than those who reported low job satisfaction under high work stress. We can conclude that physicians' mental health is likely to be protected against the high demands of medical practice by maintaining or enhancing job satisfaction, and by providing training in communication and management skills

Impact of partnership for health promotion on rural women development

El-Tal El-Kibeer is one of the 4 districts of Ismailia Governorate, Egypt. Its community is a rural one with a long history of self development. At 1987, that community started a partnership project with Suez Canal University aiming to health promotion through community participation. Women at El-Tal El-Kibeer shared actively from the start of project. Young ladies were so enthusiastic in training and in performing many of the duties of community health workers as following up growth and development of babies of their village, sharing in surveys,etc. A class for training young ladies and girls on sewing, knitting, needle work, cooking, etc. was opened in collaboration with a NGO at one of the hamlets. That center is serving the whole district and would prepare young ladies and girls to be skillful wives who can earn money, from their work. A comparative study was done to evaluate the impact of different training programs on the knowledge and attitude of women community health workers. Young ladies who were trained as community health workers at different hamlets were interviewed, with another matching group of young ladies from the same hamlets. The study revealed that more community health workers identified of the concept health and all processes leading to health promotion. The most important indicator was that 81.5% of them expressed their active sharing in solving any health problem at their community compared to 45% of the other non community health workers of whom 35% mentioned that solving problems is the job of men

pattern of feeding among infants [6 months-2 years] attending MCH center

This study was conducted on a systematic random sample of 400 mothers having infants below 2 years of age attending MCH center of El-Mahkama for vaccination. The mean age of the mothers was 24 +/- 5 years and for infants it was 16.5 +/- 2.5 months. The majority of women [97.2%] started breast feeding, however, only 74.5% of them successfully continued. The mean duration of breast feeding among illiterate mothers was 17.3 +/- 5.8 months, whereas it was 11.5 +/- 5.1 months among highly educated mothers. The main reasons for trend away from breast feeding before 24 months in this study was the wrongly thinking of the mothers that the period of infant's lactation is enough [32.8%] followed by workload of the mothers [21.1%], while scanty milk represented 9.4% only. The study showed that the lower social class tends to postpone weaning process beyond 6 months compared with middle and high social classes which usually start weaning practices earlier. Stepwise regression analysis was done for analyzing the factors that were assumed to affect weaning practice and revealed that social class, maternal education, sex of the baby, birth order and lastly the living in nuclear or extended families were the most important factors arranged, respectively, according to their relative importance

Study of B2-microglobulin in patients with ascites

Beta [2] microglobulin was measured in sera and ascitic fluid of 24 patients with malignant ascites, 24 patients with ascites secondary to bilharzial liver fibrosis, 18 patients with Tuberculous ascites and in sera of 24 healthy volunteer controls by enryme linked immuroassay. Serum beta [2]-microglobulin level were significantly higher in all patients with ascites than controls [1.545 +/- 0.245 mg/L]. Among the ascitic groups, the bilharzial group had the highest serum beta [2] - microglobulin [8.058 +/- 1.135mg/L] followed by the malignant group [6.461 +/- 1.007mg/L] and lastly the Tuberculous group [3.881 +/- 0.223mg/L]. In the ascitic fluid beta [2]-microglobulin was significantly higher in the tuberculous group [7.817 +/- 1.947mg/L] than the bilharzial group [5.145 +/- 0.374 mg/L] and the latter was in turn significantly higher than the malignant group [2.564 +/- 0.398mg/L]. A significant positive correlation between serum and ascitic fluid beta [2]-microglobulin levels was found only in the bilharzial group. Ascitic/serum ratio of beta [2]-microglobulin levels was >1 in Tuberculous group [2.04 +/- 0.56] and < 1 in the bilharzial and malignant groups [0.67 +/- 0.83 and 0.42 +/- 0.10 respectively]. It is concluded that estimation of either serum or ascetic fluid beta [2]-microglobulin alone is not conclusive in diagnosis of the cause of ascites. However the finding of striking rise of ascitic beta [2]-microglobulin level in conjunction with an ascetic serum ratio > 1 is highly suggestive of tuberculosis as a cause of ascites