Search Results - (Author, Cooperation:M. M. Ahmed)

2018-06-13

National Academy of Sciences

0027-8424

1091-6490

Biology

Medicine

Natural Sciences in General

2015-12-19

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Camels/*virology ; Coinfection/epidemiology/veterinary/*virology ; Coronavirus Infections/epidemiology/veterinary/*virology ; Disease Reservoirs/veterinary/*virology ; Epidemiological Monitoring ; Humans ; Middle East Respiratory Syndrome Coronavirus/classification/*genetics/*physiology ; Molecular Sequence Data ; Phylogeny ; *Recombination, Genetic ; Saudi Arabia/epidemiology

2018-11-28

Institute of Physics (IOP)

1757-8981

1757-899X

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

2018-08-06

MDPI Publishing

1424-8220

Chemistry and Pharmacology

Electrical Engineering, Measurement and Control Technology

2018-11-28

Institute of Physics (IOP)

1757-8981

1757-899X

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

1434-4475

Antimicrobial ; Potential benzimidazole derivatives ; synthesis and biological evaluation

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Zusammenfassung Die Synthese und antimikrobielle Prüfung einiger Benzimidazole mit verschiedenen heterozyklischen Substituenten in 2-Stellung wird beschrieben.

Summary The synthesis andin vitro antimicrobial evaluation of several benzimidazole derivatives with different heterocyclic nuclei at position-2 are described.

Electronic Resource

1420-9071

Springer Online Journal Archives 1860-2000

Biology

Medicine

Zusammenfassung In Papillomen, welche von nigerianischen Kindern stammten, wurden elektronenmikroskopisch Bildungen, welche als Viruspartikel anzusprechen waren; gefunden. Diese sind denjenigen Viruseinlagerungen vergleichbar, die man im Papillom des Larynx nachweisen kann.

Electronic Resource

1434-4475

2-Amino-oxadiazoles ; Active malonates ; 1,3,4-Oxadiazolo[3,2-a]pyrimidin-5-ones

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Zusammenfassung Die Synthese einiger substituierter 7-Hydroxy-5H-1,3,4-oxadiazolo[3,2-a]-pyrimidin-5-one (3) und ihrer 7-methoxy (4), 7-chloro (5) und 7-azido (6) Derivate wird beschrieben. Anstelle des erwarteten Triazolo-pyrimidinons7 entsteht bei der Reaktion von3b mitm-Toluidin 2-Phenyl-N,N′-bis(3-tolyl)-propandiamid (8). Drei Verbindungen wurden auf antimikrobakterielle und fungizide Wirkung geprüft.

Summary Syntheses of some substituted 7-hydroxy-5H-1,3,4-oxadiazolo[3,2-a]pyrimidin-5-ones (3) and their 7-methoxy (4), 7-chloro (5) and 7-azido (6) derivatives are described. 2-Phenyl-N,N′-bis(3-tolyl)propanediamide (8) was obtained, instead of the expected triazolopyrimidinone7 upon reacting3b withm-toluidine. Three compounds were screened forin vitro antibacterial and antifungal activities.

Electronic Resource

1434-4475

2-Amino-1,3,4-oxadiazoles ; Ethoxycarbonyl isocyanate ; 1,3,4-Oxadiazolol[3,2]-a]-s-triazine-5,7(6H)-diones

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Zusammenfassung Die Synthese von 1,3,4-Oxadiazolo[3,2-a]-s-triazin-5,7(6H)-dionen4 durch Kondensation von 2-Amino-5-aryl-1,3,4-oxadiazolen1 mit Ethoxycarbonylisocyanat2 wird beschrieben. Die Methylierung von4b mit Trimethylphosphat gibt das N-Methyl-Derivat5.

Summary The syntheses of 1,3,4-oxadiazolo[3,2-a]-s-triazine-5,7(6H)-diones4 through the condensation of 2-amino-5-aryl-1,3,4-oxadiazoles1 with ethoxycarbonyl isocyanate2 is described. Methylation of4b with trimethyl phosphate yielded the N-methyl derivative5.

Electronic Resource

1573-0794

Springer Online Journal Archives 1860-2000

Geosciences

Physics

Abstract Employing the Haselgrove ray tracing equations and a diffusive equilibrium model of the ionosphere, the propagation characteristics of hook whistlers recorded at low-latitude ground station Varanasi (geomag. lat., 16°6′.N) are discussed. It is shown that the two traces of the hook whistlers are caused by the VLF waves radiated from the return stroke of a lightning discharge which after penetrating the ionosphere at two different entry points, propagated to the opposite hemisphere in the whistler mode and were received at 16 geomagnetic latitude. Further the crossing of ray paths for the same frequency leads to the explanation of the hook whistler. The lower and higher cut-off frequencies are explained in terms of their deviating away from the bunch of the recorded whistler waves and crossing of ray paths for the same frequency.

Electronic Resource

1573-0794

Springer Online Journal Archives 1860-2000

Geosciences

Physics

Abstract The observed periodicity in the whistler occurrence rate recorded at our low latitude ground station at Varanasi (geomagnetic latitude, 14°55'N) is interpreted in terms of duct life time at lowL values. Power spectrum analysis of the whistler data yields a period of about 50 min for the growth and decay of ducts. Further dispersion analysis of the whistlers has qualitatively confirmed the existence of separate ducts during the period of observations.

Electronic Resource

1432-0843

Springer Online Journal Archives 1860-2000

Medicine

Abstract The genotoxic, cytotoxic and antitumor properties ofCommiphora molmol (oleo gum resin) were studied in normal and Ehrlich ascites carcinoma cell-bearing mice. In normal mice, the genotoxic and cytotoxic activity was evaluated on the bases of the frequency of micronuclei and the ratio of polychromatic to normochromatic cells in bone marrow, which was substantiated by the biochemical changes in hepatic cells. The antitumor activity ofC. molmol was evaluated from the total count and viability of Ehrlich ascites carcinoma cells and their nucleic acid, protein, malondialdehyde, and elemental concentrations in addition to observations on survival and the trend of changes in body weight. The tumors at the site of injection were evaluated for histopathological changes. Treatment withC. molmol (125–500 mg/kg) showed no clastogenicity but was found to be highly cytotoxic in normal mice. The results obtained in the Ehrlich ascites carcinoma cell-bearing mice revealed the cytotoxic and antitumor activity ofC. molmol which was found to be equivalent to those of the standard cytotoxic drug cyclophosphamide. On the basis of the nonmutagenic, antioxidative, and cytotoxic potential ofC. molmol as observed in the present study, its use in cancer therapy seems to be appropriate and further investigations are suggested.

Electronic Resource

1573-4811

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Electronic Resource

1573-4811

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Electronic Resource

1573-4803

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract Mild steel was coated by different materials using plasma spray technique. Materials used as coatings are Ni-5% Al and WC-17% Co. The thickness of the coatings varied between 0.05 to 1.5 mm. The porosity of different coatings decreased with increase in thickness of the coat. The roughness of coating material decreased after wear testing. Microstrueture study has been conducted for coatings of different materials before and after wear testing. Wear tests have been conducted under different aqueous environments at room temperature. The wear resistance of Ni-5% Al coating was improved by heat treatment. X-ray diffractometry showed the presence of NiO in the outer layer of the Ni-5% Al coating. The thickness of the coating, type of coating, heat treatment conditions, and the environment of testing proved to affect the rate of wear resistance.

Electronic Resource

1573-4803

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract Results of measurements of the d.c. electrical conductivity, optical absorption edge and infrared optical absorption of GeO2-TeO2 glasses are reported. Conduction in these glasses is found to be electronic and the hopping of polarons seems to be the dominant process in the transport mechanism. The electrical activation energy decreases with the increase of tellurium content and this decrease corresponds to a decrease in the optical energy gap. The optical gap is of the order of 2.74 eV, somewhat lower than for many other oxide based glasses. Most of the sharp absorption bands characteristic of the basic materials GeO2 and TeO2 are modified with the formation of broad and strong absorption bands in the process of going from the crystalline to the amorphous state. Density measurements show the glasses to have a compact structure.

Electronic Resource

1573-7438

Springer Online Journal Archives 1860-2000

Medicine

Résumé Pendant la saison sèche de février à mai 1985 les taux d'infestation par les trypanosomes de Glossines du genreG. morsitans submorsitans ont été étudiés dans quatre zones en utilisant des écrans attractifs, des animaux-appâts et des pièges. Le taux global d'infestation des mouches tsé-tsé capturées dans ces zones était de 5,1%. Le taux relatif aux trypanosomes du groupevivax représentait 64,7% du nombre total des mouches infestées pour 31,2% pour les trypanosomes du groupecongolense et 3,9% pour ceux du groupebrucei. Les infestations par trypanosomes immatures représentaient 27,3% du total pour lesvivax et 31,3% pour lescongolense. Des infestations mixtes ont été trouvées chez quelques mouches. Les taux d'infestation des mouches variaient en fonction de la technique d'échantillonnage utilisée. Une corrélation linéaire positive existait entre l'âge physiologique des mâles et leur taux d'infestation par les trypanosomes.

Resumen Se investigó la tasa de infección con tripanosoma deG.m. submorsitans, en Bahr El Arab, Sudan. La metodología consistió en atrapar moscas en cuatro áreas, utilizando mallas y animales vivos como carnada, y trampas. El estudio comenzó durante el período seco en febrero y continuó hasta mayo 1985. La tasa de infección encontrada en las moscas tsetse capturadas en las cuatro áreas fue de 5.1%. La tasa de infección del grupo de tripanosomasvivax fue 64.7%, del total de la infección; la tasa de infección del grupocongolense fue de 31.2% y del grupo brucei 3.9%. El 27.3% de infecciones convivax y el 31.3% decongolense, fueron inmaduras. Se encontraron infecciones mixtas en algunas moscas. La tasa de infección de las moscas varió con la técnica de muestreo empleada. Se encontró una correlación linear positiva, entre la edad fisiológica de los machos y la tasa de infección de los mismos.

Summary Trypanosome infection rate ofGlossina morsitans submorsitans in Bahr El Arab fly belt, Sudan was investigated in four areas using fly rounds with screen and bait animals together with traps during the dry season February to May 1985. The overall infection rate of tsetse flies captured in the four areas was 5.1%. The infection rate ofvivax group trypanosomes comprised 64.7% of total infections,congolense group 31.2% andbrucei group typanosomes 3.9%: 27.3% of thevivax and 31.3% of thecongolense were immature trypanosome infections. Mixed trypanosome infections were encountered in a few flies. Trypanosome infection rate of flies differed with the sampling technique employed. A linear positive correlation existed between the physiological age of males and their trypanosome infection rates.

Electronic Resource

1573-7438

Springer Online Journal Archives 1860-2000

Medicine

Résumé On a étudié avec des pièges biconiques la distribution, la composition des populations, le taux d'insémination, l'état de fécondation, la pyramide des âges et le taux d'infection trypanosomienne deGlossina pallidipes pendant la saison des pluies 1982 et la saison sèche 1983 à Mareerrey, en Somalie. Les mouches rassemblées dans la forêt galerie ensaison sèche, sont dispersées dans un rayon d'environ 1 km des fourrés àAcacia en saison des pluies. Il n'y a pas de variations significatives des paramètres des populations deG. pallidipes entre les deux saisons. Le rapport mâle/femelle reste 0.5:1 dans les deux saisons. Le taux d'insémination des femelles est significativement plus élevé en saison des pluies. Les états des fécondations ne sont pas statistiquement différents entre les deux périodes d'étude. On a trouvé une proportion significativement plus élevée de femelles en dessous de la catégorie 4 en saison des pluies. Le taux d'infection trypanosomienne est de 2.6% et 1.5% respectivement en saison des pluies et en saison sèche. On n'a trouvé de mouches infectées que par des trypanosomes des groupesvivax etcongolense. Une corrélation linéaire positive existe entre le taux d'infection et d'âge physiologique des femelles.

Resumen Se estudió la distribución, composición de la población, tasa de inseminación, preñes, edad y tasa de infección conTrypanosoma deGlossina pallidipes, durante la estación lluviosa de 1982 y seca de 1983, en Mareerrey Somália. Para el efecto, se utilizaron trampas bicónicas. Se encontró, que las moscas restringidas a los bosques de galería durante la estación seca, se dispersan aproximadamente 1 km afuera del monte deAcacia en la estación lluviosa. No hubo variación poblacional significativa de la mosca entre estaciones. El rango macho: hembra se mantuvo 0.5:1 en ambas estaciones. La tasa de inseminación de las hembras fue significativamente alta en la estación lluviosa. No se notó diferencia estadística en estados de preñez entre los períodos de estudio. Durante la estación lluviosa, se encontró un mayor número de hembras por debajo de la categoría de edad 4. La tasa de infección conTrypanosoma fue de 2.6% y 1.5% en la estación lluviosa y seca respectivamente. Las moscas se encontraron infectadas, solamente con los tripanosomas del grupo vivax y congolense. Se encontró tambien, una correlación linear positiva, entre la infección con tripanosomas y la edad fisiológica de las moscas.

Summary Using biconical traps the distribution, population composition, insemination rate, pregnancy, age structure and trypanosome infection rate ofG. pallidipes were studied during the wet season 1982 and the dry season 1983 at Mareerry Somalia. Flies restricted to the riverine gallery forest in the dry season become dispersed into approximately 1 km of theAcacia thickets in the wet season. There was no significant variation in population components ofG. pallidipes between wet and dry seasons. The male: female ratio remained at 0.5:1 in both seasons. The insemination rate of females was significantly high during the wet season. Pregnancy stages were not statistically different between the two study periods. A significantly greater proportion of females that were below age category 4 were found in the wet season. The trypanosome infection rate was 2.6% and 1.5% in the wet and dry seasons respectively. Flies were found infected with only the vivax and congolense group trypanosomes. A linear positive correlation existed between the trypanosome infection rate and the physiological age of females.

Electronic Resource

1573-7438

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1572-9575

Springer Online Journal Archives 1860-2000

Physics

Abstract The nonlinear and multiphoton interaction between a single two-level atom and two modes of radiation is studied in a generalized Jaynes-Cummings model. An intensity-dependent level shift is considered. The time evolution operator is obtained. The detuning has a photon number dependence. Different statistical aspects pertaining to either the atom or the fields are calculated. The dipole moment, the dipole-dipole correlation function, as well as the transient spectrum are obtained.

Electronic Resource