Hashim Osman - Academia.edu (original) (raw)

Papers by Hashim Osman

The Journal of Nutrition, 2000

Circulation Research, 2006

Inwardly rectifying K ϩ (Kir) channels are responsible for maintaining endothelial membrane poten... more Inwardly rectifying K ϩ (Kir) channels are responsible for maintaining endothelial membrane potential and play a key role in endothelium-dependent vasorelaxation. In this study, we show that endothelial Kir channels are suppressed by hypercholesterolemic levels of lipoproteins in vitro and by serum hypercholesterolemia in vivo. Specifically, exposing human aortic endothelial cells to acetylated low-density lipoprotein or very low density lipoprotein resulted in a time-and concentration-dependent decrease in Kir current that correlated with the degree of cholesterol loading. The suppression was fully reversible by cholesterol depletion. Furthermore, a decrease in Kir current resulted in depolarization of endothelial membrane potential. Most important, the flow sensitivity of Kir currents was also impaired by cholesterol loading. Specifically, flow-induced increase in Kir current was suppressed by 70%, and flow-induced hyperpolarization was almost completely abrogated. Furthermore, we show that hypercholesterolemia in vivo also strongly suppresses endothelial Kir currents and causes a shift in endothelial membrane potential, as determined by comparing the currents in aortic endothelial cells freshly isolated from healthy or hypercholesterolemic pigs. Therefore, we suggest that suppression of Kir current is one of the important factors in hypercholesterolemia-induced endothelial dysfunction. (Circ Res. 2006;98:1064-1071.)

Journal of …

Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10 -30% of the copper present in conn... more Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10 -30% of the copper present in connective tissue. Herein, we assess the extent to which tissue copper concentrations and lysyl oxidase activity are related because the functional activity of lysyl oxidase and the copper content of chick tendon are both related to dietary copper intake. Chicks (1-d old) were fed diets (basal copper concentration, 0.4 g/g diet) to which copper was added from 0 to 16 g/g diet. Liver and plasma copper levels tended to normalize in chickens that consumed from 1 to 4 g copper/g of diet, whereas tendon copper concentrations suggested an unusual accumulation of copper in chickens that consumed 16 g copper/g diet. The molecular weight of lysyl oxidase was also estimated using matrix-assisted laser desorption ionization/time-of-flight/ mass spectrometry (MALDI/TOF/MS). A novel aspect of these measurements was estimation of protein mass directly from the surface of chick tendons and aortae. Whether copper deficiency (0 added copper) or copper supplementation (16 g copper/g of diet) caused changes in the molecular weight of protein(s) in tendon corresponding to lysyl oxidase was addressed. The average molecular weight of the peak corresponding to lysyl oxidase in tendon and aorta from copper-deficient birds was 28,386 Da ؎ 86, whereas the average molecular weight of corresponding protein in tendon from copper-supplemented birds was 28,639 Da ؎ 122. We propose that the shift in molecular weight is due in part to copper binding and the formation of lysyl tyrosyl quinone, the cofactor at the active site of lysyl oxidase.

Aids Patient Care and Stds, 1997

HIV surveillance and screening programs were established at Khartoum Teaching Hospital (KTH) foll... more HIV surveillance and screening programs were established at Khartoum Teaching Hospital (KTH) following the first identified HIV case diagnosed in a hemophiliac boy in November 1987. As of December 1995, 15 cases of symptomatic HIV infection have been observed in Sudanese children (< or = 16 years) at KTH. An HIV seroprevalence rate of 35.7% was documented in a group of 28 patients (adults and children) with various congenital coagulation defects. The postulated mode of transmission was through contaminated factor concentrate. Screening of 52,000 volunteer male blood donors (March, 1987-1989) showed an HIV-seroprevalence rate of 0.05%. Selected groups, including 1118 children admitted to KTH during the period 1985-1995, were screened for HIV infection. These included aseptic meningitis/encephalitis group (n = 52), high-risk group (n = 523), children with various chronic and malignant diseases (n = 181), and chronic blood recipients (n = 330). A group of 32 displaced homeless children who survived on the streets were also included. Overall, an HIV seroprevalence rate of 1.2% was established. Among the 15 children with symptomatic HIV infection, tuberculosis accounted for the majority of admissions (33.3%) followed by admission for recurrent infections (20.0%). Of the 13 children with nonparental mode of HIV transmission, a vertical mode was documented in 61.5%. The pattern of HIV infection in Greater Khartoum is similar to that in North Africa and the Middle East. However, the geographic influence of high endemicity in neighboring sub-Saharan countries might change it in the future.

Acta Obstetricia Et Gynecologica Scandinavica, 2003

Background. To find out whether preterm labor is associated with raised maternal serum concentra... more Background. To find out whether preterm labor is associated with raised maternal serum concentrations of interleukin (IL)-6, IL-8, tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) and whether the measurement of these cytokines can be used to detect early intrauterine infection in preterm labor.Methods. Cross-sectional study: 77 women in preterm labor, 47 controls of healthy preterm women not in labor and 19 women in term labor. The serum cytokines levels were measured by enzyme-linked immunosorbent assay (ELISA). The newborns of women who were in labor were followed up for evidence of infection. Differences between groups were tested using analysis of variance, Student's t-test and χ2-test.Results. There was no significant difference in the concentration of all the cytokines measured between the different groups. No statistical difference was found in the concentration of the cytokines between women in preterm labor with ruptured membranes and those with intact membranes. There was also no difference found in the concentration of cytokines between women whose newborns had positive bacterial culture and those with negative culture. There was a positive correlation between the concentrations of IL-6, IL-8 and TNF-α.Conclusion. Serum levels of interleukin-6, interleukin-8 and tumor necrosis factor-α were not increased in preterm labor compared to normal control women. There is doubt regarding the usefulness of maternal serum measurement of these cytokines for the detection of early fetal infection in preterm labor, but this needs further evaluation.

Aquaculture, 2004

A study to determine the effect of increasing levels of dietary protein on swordtail (Xiphophorus... more A study to determine the effect of increasing levels of dietary protein on swordtail (Xiphophorus helleri), a popular freshwater live bearer, was carried out. Five isocaloric semi-purified diets containing 20%, 30%, 40%, 50% and 60% dietary protein were used. Broodstock performance was evaluated based on growth parameters, proximate content and fry production of female broodstock. Results showed that while the 20% and 30% protein produced the lowest specific growth rate (SGR) values, there was no significant difference between 40% and 60% dietary treatments. The 20% dietary treatment also displayed lowest protein content in both ovaries and muscle of female fish. Fry production was highest from females fed with 50% and 60% protein, followed by the 30% and 40% protein while the diet containing 20% protein produced lowest number of fry. A significant correlation was also obtained between number of fry produced and the weight of female fish, indicating that size is a major factor influencing production. Relative fecundity was lowest for the 20% protein diet followed by the 30–40% and 40–60% protein diets. There were no significant differences in both weight and length of fry produced among the dietary treatments. Proximate analysis of fry also did not show any trend with different dietary protein levels fed to female broodstock. Dietary protein requirement of female swordtail during reproduction is therefore crucial for both the somatic growth and reproduction processes in order for fry production to be optimized. Based on our results, we suggest that a minimum of 30% protein be included in the diet of female swordtail broodstock.

Transactions of The Royal Society of Tropical Medicine and Hygiene, 1997

The performance of the direct agglutination test (DAT) was evaluated under field conditions in an... more The performance of the direct agglutination test (DAT) was evaluated under field conditions in an endemic area of visceral leishmaniasis in eastern Sudan, using aqueous (Aq) antigen which has to be kept refrigerated and a newly developed freeze-dried (FD) antigen which is stable at ambient temperature. Both antigens compared well, with 92–98% of readings being identical or only with one dilution difference in titre. FD antigen gave titres that were identical with Aq antigen in 73% of samples, higher in 19%, and lower in 8%. Owing to high ambient temperatures and low humidity, microtitre plate wells dried out during the standard procedures for elution and incubation. However, shortening the elution time from 12 to 4 h proved possible for both antigens; incubation could be reduced from 24 to 10 h for Aq antigen, after which the plates could still be read. Incubation with FD antigen required 18 h and the plates needed to be kept cool because of evaporation. Despite the longer procedure with the FD antigen, the DAT can be completed in 24 h and the use of this stable antigen, that does not require refrigeration, is a major improvement in performing the DAT under unfavourable field conditions.

Force plate produces distinct M-shaped curves when set to read ground reaction forces on human wa... more Force plate produces distinct M-shaped curves when set to read ground reaction forces on human walking gait. However, force plate cannot read a person’s actual feels on interaction with the ground, that is, the ground reaction forces. In fact, unique structural configuration found in human foot allows easy walking where similar movement is hard to imitate even for an ape. It is obvious that the characteristics of human walking gait relates to the foot’s structure. Foot is modeled where bones are represented by vertices and joints by edges. A graph is then developed to represent the whole foot. By inspection there are twelve points on foot flat that have immediate contact with the ground reaction forces. It is suspected that these points function as the stabilizing nodes. This work proposes a method where profiles of human walking gait can be created through mathematical argument. It is done by exploiting the advantages found in graph theory and general methods in mathematics.

Color and color difference are important information for a lesion in dermatological diagnosis. Th... more Color and color difference are important information for a lesion in dermatological diagnosis. This paper presents various supervised ANN models for plaque classification using RGB indices. Images are taken from selected skin at the dermatological clinic which the images are captured using digital camera with controlled environment. The analysis of dermatological digital images is performed by measurements of the pixels that represent a segmented cropped area of the skin lesion. The segmentation of the skin image could be accomplished automatically by supervised segmentation algorithms. The proposed models are designed by implementing Levenberg Marquardt feedforward, Radial Basis Function algorithm and backpropagation. Each optimized model are evaluated and validated through analysis of the performance indicators regularly applied in classification models. At later stage, the best performance from these models is compared with other researchers' work in this area, but using different color space such as YCbCr and HSV.

The paper presents an upgrading process of rubber tree seed clones identification model using ima... more The paper presents an upgrading process of rubber tree seed clones identification model using image processing techniques. Sample of rubber tree seeds are captured using digital camera where the RGB color image are processed involving segmentation algorithm which includes thresholding and morphological technique. Texture patterns from seed clones images are then analysed through wavelet's Daubechies D4 algorithm which produced discrete frequency coefficients representing the extracted features. Previous work only utilized three statistical parameters representing these coefficients such as mean, variance and standard deviation as the inputs for designing an intelligent identification model for various rubber tree seed clones. However, the accuracy was not that convincing. This work has proposed to use seven input parameter in order to improve the model's accuracy. In this work, 285 sample images representing three types of rubber tree seed clones are used to train Artificial Neural Network (ANN) with Levenberg Marquardt algorithm. Two models are being designed, known as Model 1 and Model 2, to identify seed clones RRIM2005 and RRIM2009 respectively. The outcomes have shown that both models' accuracy has improved but not that substantial.

European Journal of Clinical Pharmacology, 2010

Purpose The aim of this study was to investigate the efficacy of artemether-lumefantrine in treat... more Purpose The aim of this study was to investigate the efficacy of artemether-lumefantrine in treating uncomplicated Plasmodium falciparum malaria in four sentinel areas in Sudan with different malaria transmission (Damazin, Sinnar, and Kosti in the north, and Juba in the south). Methods World Health Organization protocol for assessing antimalarial drug efficacy in treating uncomplicated P. falciparum malaria was employed. A total of 2,139 patients were screened, and 771 had P. falciparum monoinfection. Only 291 met the enrollment criteria and gave written consent to be recruited in the study. Patients were treated with artemether-lumefantrine tablets in a six-dose regimen calculated according to body weight. Tablets were given at 0, 8, 24, 36, 48, and 60 h. Patients were followed up for 28 days. Results A total of 291 patients were recruited to the study, of whom ten [3.4; 95% confidence interval (CI):1.8–6.4%] patients showed early treatment failure (ETF) or late clinical failure (LCF) and were excluded from further follow-up. Of the remaining 281 patients, 276 (98.2%; 95% CI: 95.7–99.3%) completed the 28-day follow-up. Of these, 274 (99.3%; 95% CI: 97.1–99.9%) had adequate clinical and parasitological response (ACPR), and two (0.7%; 95% CI: 0.13–2.9%) showed late parasitological failure (LPF) at days 21 and 28. The overall mean ± standard deviation (SD) of parasitemia and fever clearance times were 36.4 (23.7) h and 34.6 (19.2) h, respectively. Mild and reversible adverse effects were reported by 11 patients (3.8%; CI: 2.0–7.0%) and were relieved without the need for termination of drug therapy or supportive treatment. Conclusions Our findings showed that artemether-lumefantrine was an effective and safe drug for treating uncomplicated P. falciparum malaria in northern and southern Sudan.

Abstract—This paper describes research work in developing an intelligent model for classifying se... more Abstract—This paper describes research work in developing an intelligent model for classifying selected rubber tree series clones based on shape features using image processing techniques. Sample of rubber tree seeds are captured using digital camera where the ...

Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2010

The Schottky diodes enjoined with coplanar waveguides are investigated for applications in on-chi... more The Schottky diodes enjoined with coplanar waveguides are investigated for applications in on-chip rectenna device application without insertion of a matching circuit. The design, fabrication, DC characteristics and RF-to-DC conversion of the AlGaAs/GaAs HEMT Schottky diode is presented. The RF signals are well converted by the fabricated Schottky diodes with cut-off frequency up to 20 GHz estimated in direct injection experiments. The outcomes of these results provide conduit for breakthrough designs for ultra-low power on-chip rectenna device technology to be integrated in nanosystems.

This paper presents the development of an interactive learning environment for dynamic simulation... more This paper presents the development of an interactive learning environment for dynamic simulation and active vibration control of flexible plate structures. The work is aimed to facilitate the learning process of the subject area through the development of an interactive environment that can help users to simulate and visualise behaviour of flexible structures with given physical characteristics, to test and validate controller designs. Simulation algorithms based on finite difference scheme in characterizing the dynamic behaviour of a two-dimensional such as plate structures are incorporated. Controller design strategies are integrated within this framework. The design and implementation of the interactive learning system incorporating the simulation algorithms, modelling and control strategies, are developed using Matlab. The result of the simulation is further utilized in the modelling and control of the specified flexible plate structure.

... S. 2. Mohd Hashim, M. 0. Tokhi and IZ Mat Dams Department of Automatic Control and Systems En... more ... S. 2. Mohd Hashim, M. 0. Tokhi and IZ Mat Dams Department of Automatic Control and Systems Engineering, The Universiry of Shefield ... A comparative performance of the NN model and conventional recursive least square scheme, in characterising the system is carried out in ...

This paper presents an investigation into the utilization of genetic algorithms (GAs) for dynamic... more This paper presents an investigation into the utilization of genetic algorithms (GAs) for dynamic modelling and simulation of flexible beam structures. The global search technique of GA is utilised to identify the parameters of a beam model based on one-step-ahead prediction in fixed-free mode; a simple representation of an aircraft wing or robot arm. A pseudo random binary sequence (PRBS)

Acta Crystallographica Section E-structure Reports Online, 2010

Key indicators: single-crystal X-ray study; T = 100 K; mean (C-C) = 0.002 Å; R factor = 0.037; wR... more Key indicators: single-crystal X-ray study; T = 100 K; mean (C-C) = 0.002 Å; R factor = 0.037; wR factor = 0.155; data-to-parameter ratio = 26.5.

Journal of Low Frequency Noise Vibration and Active Control, 2006

The paper discusses the use of a simple position control system approach to improve the performan... more The paper discusses the use of a simple position control system approach to improve the performance of lightly damped dynamic systems. This approach uses a delayed position feedback signal to actively control the vibrations of flexible structures. A complete analysis of the stability of a single-link flexible manipulator under time delay control is presented and critical values of time delay for a given controller gain have been determined. The paper also presents a short comparison between the delayed feedback signal control and the linear quadratic regulator.

Robotica, 2006

... 2. 2. S. Yurkovich, "Flexibility effects on performance and cont... more ... 2. 2. S. Yurkovich, "Flexibility effects on performance and control" In: Robot Control (Eds.: MW Spong, FL Lewis and CT Abdallah, IEEE Press, 1992), Part 8, pp. 321-323. ... Collaborative Colleagues: Z. Mohamed: colleagues. AK Chee: colleagues. AWIMohd Hashim: colleagues. ...

Coronary artery disease is responsible for much mortality and morbidity around the world. Platele... more Coronary artery disease is responsible for much mortality and morbidity around the world. Platelets are involved in atherosclerotic disease development and the reduction of platelet activity by medications reduces the incidence and severity of disease. Red wine and grapes contain polyphenolic compounds, including flavonoids, which can reduce platelet aggregation and have been associated with lower rates of cardiovascular disease. Citrus fruits contain different classes of polyphenolics that may not share the same properties. This study evaluated whether commercial grape, orange and grapefruit juices, taken daily, reduce ex vivo platelet activity. In a randomized cross-over design, ten healthy human subjects (ages 26 -58 y, five of each gender) drank 5-7.5 mL/(kg ⅐ d) of purple grape juice, orange juice or grapefruit juice for 7-10 d each. Platelet aggregation (whole blood impedance aggregometry, Chronolog Model #590) at baseline was compared to results after consumption of each juice. Drinking purple grape juice for one week reduced the whole blood platelet aggregation response to 1 mg/L of collagen by 77% (from 17.9 ؎ 2.3 to 4.0 ؎ 6.8 ohms, P ‫؍‬ 0.0002). Orange juice and grapefruit juice had no effect on platelet aggregation. The purple grape juice had approximately three times the total polyphenolic concentration of the citrus juices and was a potent platelet inhibitor in healthy subjects while the citrus juices showed no effect. The platelet inhibitory effect of the flavonoids in grape juice may decrease the risk of coronary thrombosis and myocardial infarction. J. Nutr. 130: 53-56, 2000.

The Journal of Nutrition, 2000

Circulation Research, 2006

Inwardly rectifying K ϩ (Kir) channels are responsible for maintaining endothelial membrane poten... more Inwardly rectifying K ϩ (Kir) channels are responsible for maintaining endothelial membrane potential and play a key role in endothelium-dependent vasorelaxation. In this study, we show that endothelial Kir channels are suppressed by hypercholesterolemic levels of lipoproteins in vitro and by serum hypercholesterolemia in vivo. Specifically, exposing human aortic endothelial cells to acetylated low-density lipoprotein or very low density lipoprotein resulted in a time-and concentration-dependent decrease in Kir current that correlated with the degree of cholesterol loading. The suppression was fully reversible by cholesterol depletion. Furthermore, a decrease in Kir current resulted in depolarization of endothelial membrane potential. Most important, the flow sensitivity of Kir currents was also impaired by cholesterol loading. Specifically, flow-induced increase in Kir current was suppressed by 70%, and flow-induced hyperpolarization was almost completely abrogated. Furthermore, we show that hypercholesterolemia in vivo also strongly suppresses endothelial Kir currents and causes a shift in endothelial membrane potential, as determined by comparing the currents in aortic endothelial cells freshly isolated from healthy or hypercholesterolemic pigs. Therefore, we suggest that suppression of Kir current is one of the important factors in hypercholesterolemia-induced endothelial dysfunction. (Circ Res. 2006;98:1064-1071.)

Journal of …

Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10 -30% of the copper present in conn... more Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10 -30% of the copper present in connective tissue. Herein, we assess the extent to which tissue copper concentrations and lysyl oxidase activity are related because the functional activity of lysyl oxidase and the copper content of chick tendon are both related to dietary copper intake. Chicks (1-d old) were fed diets (basal copper concentration, 0.4 g/g diet) to which copper was added from 0 to 16 g/g diet. Liver and plasma copper levels tended to normalize in chickens that consumed from 1 to 4 g copper/g of diet, whereas tendon copper concentrations suggested an unusual accumulation of copper in chickens that consumed 16 g copper/g diet. The molecular weight of lysyl oxidase was also estimated using matrix-assisted laser desorption ionization/time-of-flight/ mass spectrometry (MALDI/TOF/MS). A novel aspect of these measurements was estimation of protein mass directly from the surface of chick tendons and aortae. Whether copper deficiency (0 added copper) or copper supplementation (16 g copper/g of diet) caused changes in the molecular weight of protein(s) in tendon corresponding to lysyl oxidase was addressed. The average molecular weight of the peak corresponding to lysyl oxidase in tendon and aorta from copper-deficient birds was 28,386 Da ؎ 86, whereas the average molecular weight of corresponding protein in tendon from copper-supplemented birds was 28,639 Da ؎ 122. We propose that the shift in molecular weight is due in part to copper binding and the formation of lysyl tyrosyl quinone, the cofactor at the active site of lysyl oxidase.

Aids Patient Care and Stds, 1997

HIV surveillance and screening programs were established at Khartoum Teaching Hospital (KTH) foll... more HIV surveillance and screening programs were established at Khartoum Teaching Hospital (KTH) following the first identified HIV case diagnosed in a hemophiliac boy in November 1987. As of December 1995, 15 cases of symptomatic HIV infection have been observed in Sudanese children (< or = 16 years) at KTH. An HIV seroprevalence rate of 35.7% was documented in a group of 28 patients (adults and children) with various congenital coagulation defects. The postulated mode of transmission was through contaminated factor concentrate. Screening of 52,000 volunteer male blood donors (March, 1987-1989) showed an HIV-seroprevalence rate of 0.05%. Selected groups, including 1118 children admitted to KTH during the period 1985-1995, were screened for HIV infection. These included aseptic meningitis/encephalitis group (n = 52), high-risk group (n = 523), children with various chronic and malignant diseases (n = 181), and chronic blood recipients (n = 330). A group of 32 displaced homeless children who survived on the streets were also included. Overall, an HIV seroprevalence rate of 1.2% was established. Among the 15 children with symptomatic HIV infection, tuberculosis accounted for the majority of admissions (33.3%) followed by admission for recurrent infections (20.0%). Of the 13 children with nonparental mode of HIV transmission, a vertical mode was documented in 61.5%. The pattern of HIV infection in Greater Khartoum is similar to that in North Africa and the Middle East. However, the geographic influence of high endemicity in neighboring sub-Saharan countries might change it in the future.

Acta Obstetricia Et Gynecologica Scandinavica, 2003

Background. To find out whether preterm labor is associated with raised maternal serum concentra... more Background. To find out whether preterm labor is associated with raised maternal serum concentrations of interleukin (IL)-6, IL-8, tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) and whether the measurement of these cytokines can be used to detect early intrauterine infection in preterm labor.Methods. Cross-sectional study: 77 women in preterm labor, 47 controls of healthy preterm women not in labor and 19 women in term labor. The serum cytokines levels were measured by enzyme-linked immunosorbent assay (ELISA). The newborns of women who were in labor were followed up for evidence of infection. Differences between groups were tested using analysis of variance, Student's t-test and χ2-test.Results. There was no significant difference in the concentration of all the cytokines measured between the different groups. No statistical difference was found in the concentration of the cytokines between women in preterm labor with ruptured membranes and those with intact membranes. There was also no difference found in the concentration of cytokines between women whose newborns had positive bacterial culture and those with negative culture. There was a positive correlation between the concentrations of IL-6, IL-8 and TNF-α.Conclusion. Serum levels of interleukin-6, interleukin-8 and tumor necrosis factor-α were not increased in preterm labor compared to normal control women. There is doubt regarding the usefulness of maternal serum measurement of these cytokines for the detection of early fetal infection in preterm labor, but this needs further evaluation.

Aquaculture, 2004

A study to determine the effect of increasing levels of dietary protein on swordtail (Xiphophorus... more A study to determine the effect of increasing levels of dietary protein on swordtail (Xiphophorus helleri), a popular freshwater live bearer, was carried out. Five isocaloric semi-purified diets containing 20%, 30%, 40%, 50% and 60% dietary protein were used. Broodstock performance was evaluated based on growth parameters, proximate content and fry production of female broodstock. Results showed that while the 20% and 30% protein produced the lowest specific growth rate (SGR) values, there was no significant difference between 40% and 60% dietary treatments. The 20% dietary treatment also displayed lowest protein content in both ovaries and muscle of female fish. Fry production was highest from females fed with 50% and 60% protein, followed by the 30% and 40% protein while the diet containing 20% protein produced lowest number of fry. A significant correlation was also obtained between number of fry produced and the weight of female fish, indicating that size is a major factor influencing production. Relative fecundity was lowest for the 20% protein diet followed by the 30–40% and 40–60% protein diets. There were no significant differences in both weight and length of fry produced among the dietary treatments. Proximate analysis of fry also did not show any trend with different dietary protein levels fed to female broodstock. Dietary protein requirement of female swordtail during reproduction is therefore crucial for both the somatic growth and reproduction processes in order for fry production to be optimized. Based on our results, we suggest that a minimum of 30% protein be included in the diet of female swordtail broodstock.

Transactions of The Royal Society of Tropical Medicine and Hygiene, 1997

The performance of the direct agglutination test (DAT) was evaluated under field conditions in an... more The performance of the direct agglutination test (DAT) was evaluated under field conditions in an endemic area of visceral leishmaniasis in eastern Sudan, using aqueous (Aq) antigen which has to be kept refrigerated and a newly developed freeze-dried (FD) antigen which is stable at ambient temperature. Both antigens compared well, with 92–98% of readings being identical or only with one dilution difference in titre. FD antigen gave titres that were identical with Aq antigen in 73% of samples, higher in 19%, and lower in 8%. Owing to high ambient temperatures and low humidity, microtitre plate wells dried out during the standard procedures for elution and incubation. However, shortening the elution time from 12 to 4 h proved possible for both antigens; incubation could be reduced from 24 to 10 h for Aq antigen, after which the plates could still be read. Incubation with FD antigen required 18 h and the plates needed to be kept cool because of evaporation. Despite the longer procedure with the FD antigen, the DAT can be completed in 24 h and the use of this stable antigen, that does not require refrigeration, is a major improvement in performing the DAT under unfavourable field conditions.

Force plate produces distinct M-shaped curves when set to read ground reaction forces on human wa... more Force plate produces distinct M-shaped curves when set to read ground reaction forces on human walking gait. However, force plate cannot read a person’s actual feels on interaction with the ground, that is, the ground reaction forces. In fact, unique structural configuration found in human foot allows easy walking where similar movement is hard to imitate even for an ape. It is obvious that the characteristics of human walking gait relates to the foot’s structure. Foot is modeled where bones are represented by vertices and joints by edges. A graph is then developed to represent the whole foot. By inspection there are twelve points on foot flat that have immediate contact with the ground reaction forces. It is suspected that these points function as the stabilizing nodes. This work proposes a method where profiles of human walking gait can be created through mathematical argument. It is done by exploiting the advantages found in graph theory and general methods in mathematics.

Color and color difference are important information for a lesion in dermatological diagnosis. Th... more Color and color difference are important information for a lesion in dermatological diagnosis. This paper presents various supervised ANN models for plaque classification using RGB indices. Images are taken from selected skin at the dermatological clinic which the images are captured using digital camera with controlled environment. The analysis of dermatological digital images is performed by measurements of the pixels that represent a segmented cropped area of the skin lesion. The segmentation of the skin image could be accomplished automatically by supervised segmentation algorithms. The proposed models are designed by implementing Levenberg Marquardt feedforward, Radial Basis Function algorithm and backpropagation. Each optimized model are evaluated and validated through analysis of the performance indicators regularly applied in classification models. At later stage, the best performance from these models is compared with other researchers' work in this area, but using different color space such as YCbCr and HSV.

The paper presents an upgrading process of rubber tree seed clones identification model using ima... more The paper presents an upgrading process of rubber tree seed clones identification model using image processing techniques. Sample of rubber tree seeds are captured using digital camera where the RGB color image are processed involving segmentation algorithm which includes thresholding and morphological technique. Texture patterns from seed clones images are then analysed through wavelet's Daubechies D4 algorithm which produced discrete frequency coefficients representing the extracted features. Previous work only utilized three statistical parameters representing these coefficients such as mean, variance and standard deviation as the inputs for designing an intelligent identification model for various rubber tree seed clones. However, the accuracy was not that convincing. This work has proposed to use seven input parameter in order to improve the model's accuracy. In this work, 285 sample images representing three types of rubber tree seed clones are used to train Artificial Neural Network (ANN) with Levenberg Marquardt algorithm. Two models are being designed, known as Model 1 and Model 2, to identify seed clones RRIM2005 and RRIM2009 respectively. The outcomes have shown that both models' accuracy has improved but not that substantial.

European Journal of Clinical Pharmacology, 2010

Purpose The aim of this study was to investigate the efficacy of artemether-lumefantrine in treat... more Purpose The aim of this study was to investigate the efficacy of artemether-lumefantrine in treating uncomplicated Plasmodium falciparum malaria in four sentinel areas in Sudan with different malaria transmission (Damazin, Sinnar, and Kosti in the north, and Juba in the south). Methods World Health Organization protocol for assessing antimalarial drug efficacy in treating uncomplicated P. falciparum malaria was employed. A total of 2,139 patients were screened, and 771 had P. falciparum monoinfection. Only 291 met the enrollment criteria and gave written consent to be recruited in the study. Patients were treated with artemether-lumefantrine tablets in a six-dose regimen calculated according to body weight. Tablets were given at 0, 8, 24, 36, 48, and 60 h. Patients were followed up for 28 days. Results A total of 291 patients were recruited to the study, of whom ten [3.4; 95% confidence interval (CI):1.8–6.4%] patients showed early treatment failure (ETF) or late clinical failure (LCF) and were excluded from further follow-up. Of the remaining 281 patients, 276 (98.2%; 95% CI: 95.7–99.3%) completed the 28-day follow-up. Of these, 274 (99.3%; 95% CI: 97.1–99.9%) had adequate clinical and parasitological response (ACPR), and two (0.7%; 95% CI: 0.13–2.9%) showed late parasitological failure (LPF) at days 21 and 28. The overall mean ± standard deviation (SD) of parasitemia and fever clearance times were 36.4 (23.7) h and 34.6 (19.2) h, respectively. Mild and reversible adverse effects were reported by 11 patients (3.8%; CI: 2.0–7.0%) and were relieved without the need for termination of drug therapy or supportive treatment. Conclusions Our findings showed that artemether-lumefantrine was an effective and safe drug for treating uncomplicated P. falciparum malaria in northern and southern Sudan.

Abstract—This paper describes research work in developing an intelligent model for classifying se... more Abstract—This paper describes research work in developing an intelligent model for classifying selected rubber tree series clones based on shape features using image processing techniques. Sample of rubber tree seeds are captured using digital camera where the ...

Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2010

The Schottky diodes enjoined with coplanar waveguides are investigated for applications in on-chi... more The Schottky diodes enjoined with coplanar waveguides are investigated for applications in on-chip rectenna device application without insertion of a matching circuit. The design, fabrication, DC characteristics and RF-to-DC conversion of the AlGaAs/GaAs HEMT Schottky diode is presented. The RF signals are well converted by the fabricated Schottky diodes with cut-off frequency up to 20 GHz estimated in direct injection experiments. The outcomes of these results provide conduit for breakthrough designs for ultra-low power on-chip rectenna device technology to be integrated in nanosystems.

This paper presents the development of an interactive learning environment for dynamic simulation... more This paper presents the development of an interactive learning environment for dynamic simulation and active vibration control of flexible plate structures. The work is aimed to facilitate the learning process of the subject area through the development of an interactive environment that can help users to simulate and visualise behaviour of flexible structures with given physical characteristics, to test and validate controller designs. Simulation algorithms based on finite difference scheme in characterizing the dynamic behaviour of a two-dimensional such as plate structures are incorporated. Controller design strategies are integrated within this framework. The design and implementation of the interactive learning system incorporating the simulation algorithms, modelling and control strategies, are developed using Matlab. The result of the simulation is further utilized in the modelling and control of the specified flexible plate structure.

... S. 2. Mohd Hashim, M. 0. Tokhi and IZ Mat Dams Department of Automatic Control and Systems En... more ... S. 2. Mohd Hashim, M. 0. Tokhi and IZ Mat Dams Department of Automatic Control and Systems Engineering, The Universiry of Shefield ... A comparative performance of the NN model and conventional recursive least square scheme, in characterising the system is carried out in ...

This paper presents an investigation into the utilization of genetic algorithms (GAs) for dynamic... more This paper presents an investigation into the utilization of genetic algorithms (GAs) for dynamic modelling and simulation of flexible beam structures. The global search technique of GA is utilised to identify the parameters of a beam model based on one-step-ahead prediction in fixed-free mode; a simple representation of an aircraft wing or robot arm. A pseudo random binary sequence (PRBS)

Acta Crystallographica Section E-structure Reports Online, 2010

Key indicators: single-crystal X-ray study; T = 100 K; mean (C-C) = 0.002 Å; R factor = 0.037; wR... more Key indicators: single-crystal X-ray study; T = 100 K; mean (C-C) = 0.002 Å; R factor = 0.037; wR factor = 0.155; data-to-parameter ratio = 26.5.

Journal of Low Frequency Noise Vibration and Active Control, 2006

The paper discusses the use of a simple position control system approach to improve the performan... more The paper discusses the use of a simple position control system approach to improve the performance of lightly damped dynamic systems. This approach uses a delayed position feedback signal to actively control the vibrations of flexible structures. A complete analysis of the stability of a single-link flexible manipulator under time delay control is presented and critical values of time delay for a given controller gain have been determined. The paper also presents a short comparison between the delayed feedback signal control and the linear quadratic regulator.

Robotica, 2006

... 2. 2. S. Yurkovich, "Flexibility effects on performance and cont... more ... 2. 2. S. Yurkovich, "Flexibility effects on performance and control" In: Robot Control (Eds.: MW Spong, FL Lewis and CT Abdallah, IEEE Press, 1992), Part 8, pp. 321-323. ... Collaborative Colleagues: Z. Mohamed: colleagues. AK Chee: colleagues. AWIMohd Hashim: colleagues. ...

Coronary artery disease is responsible for much mortality and morbidity around the world. Platele... more Coronary artery disease is responsible for much mortality and morbidity around the world. Platelets are involved in atherosclerotic disease development and the reduction of platelet activity by medications reduces the incidence and severity of disease. Red wine and grapes contain polyphenolic compounds, including flavonoids, which can reduce platelet aggregation and have been associated with lower rates of cardiovascular disease. Citrus fruits contain different classes of polyphenolics that may not share the same properties. This study evaluated whether commercial grape, orange and grapefruit juices, taken daily, reduce ex vivo platelet activity. In a randomized cross-over design, ten healthy human subjects (ages 26 -58 y, five of each gender) drank 5-7.5 mL/(kg ⅐ d) of purple grape juice, orange juice or grapefruit juice for 7-10 d each. Platelet aggregation (whole blood impedance aggregometry, Chronolog Model #590) at baseline was compared to results after consumption of each juice. Drinking purple grape juice for one week reduced the whole blood platelet aggregation response to 1 mg/L of collagen by 77% (from 17.9 ؎ 2.3 to 4.0 ؎ 6.8 ohms, P ‫؍‬ 0.0002). Orange juice and grapefruit juice had no effect on platelet aggregation. The purple grape juice had approximately three times the total polyphenolic concentration of the citrus juices and was a potent platelet inhibitor in healthy subjects while the citrus juices showed no effect. The platelet inhibitory effect of the flavonoids in grape juice may decrease the risk of coronary thrombosis and myocardial infarction. J. Nutr. 130: 53-56, 2000.