On Correlation Effect of the Van-der-Waals and Intramolecular Forces for the Nucleotide Chain - Metallic Nanoparticles - Carbon Nanotube Binding.

BACKGROUND: The tertiary system of nucleotide chain (NC) - gold nanoparticles (NPs) - carbon nanotube (CNT) represents a great interest in the modern research and application of the bio-nano-technologies. The application aspects include, for example, the development of electronic mobile diagnostic facilities, nanorobotic design for a drug delivery inside living cell, and so on. The small NC chain represents an important stage in the understanding of the interaction mechanism of a full DNA or RNA molecule with NP and CNT. In this regard, one has to mention the development of the DNA-CNT devices for the purposes of diagnostic applications in the chemical or drug delivery. METHODS: For the NC-NP-CNT system, we have built up a series of the molecular dynamics (MD) models with different NC-NP configurations and performed their MD analysis. The entire system (the NC chain, gold NPs and CNT) was allowed to interact with each other by the only VdW forces. The Lennard-Jones short-ranged interaction was assumed between the NC, NP and CNT. For the CNT a many body Tersoff potential having a quantum-chemistry nature was used. So far, the so-called hybrid MD approach was realized, where the quantum-chemistry potential in combination with a classical trajectory calculation applied . RESULTS: The peculiarities of the NC-NP interaction and bond formation inside of a CNT matrix were investigated along with the structural and dynamical behavior. The correlation effects between the weak Van der Waals (VdW) forces and intramolecular vibrations were enlighten for the molecular system consisting of a small nucleotide chain (NC), gold nanoparticles (NPs) and carbon nanotube (CNT) using molecular dynamics (MD) simulation method. CONCLUSION: The NC intermolecular motions were estimated from MD data thereby building the distance distributions, the angular and dihedral (torsional) bond energy graphs versus simulation time at different temperatures from T=100 K up to 300 K. The MD simulation results have shown that depending on the relative NC-NP position a different scenario of bonding between the NC-NP, within CNT matrix, is possible. We have observed the possibilities of formation of weak, strong and intermediate bonds between the NP-NC, which are overestimated by a presence of CNT matrix as confined environment. The NC chain can form with a particular gold atom a close contact, while with another under the same positional and temperature conditions the weak resultant bonding formation might be possible. We estimated the fluctuations in the NP-NC bonding processes for a single gold atomic case (models 1-3, NC-1NP-CNT), for the two (model 4-6, NC-2NP-CNT) and three (model 7, NC-3NP-CNT) gold particle ones. Thus, a concurrent effect between the NC intramolecular vibrations and a weak VdW interaction between the NC and gold NP were studied in detail.

Field assessment of the mid winter mass kills of trophic fishes at Mariotteya stream, Egypt: chemical and biological pollution synergistic model.

Pathogenic Candida albicans was isolated from water and fish samples collected during an emergent event of mass mortalities among the juvenile Nile tilapia (Oreochromis niloticus), Sharp toothed catfish (Clarias gariepinus) along the stream of Mariotteya drainage. Investigations indicated that fish mortalities were confined to the area of Shubramant and Aboul Noumros (North to Sakara 7 drainage). C. albicans was isolated from the lesions associated with multiple skin ulcers in both Nile tilapia juveniles and Sharp toothed catfish. Assessment of the field and laboratory data has indicated that Mariotteya environmental disaster was a multifactorial problem. The fish mass kills were initially flared up through the dumping of the improperly treated nasty organic and inorganic chemicals from Elhawamdia sugar factory and municipal sewage. The physical stagnation of the stream, high levels of ammonia, phenol and polycyclic aromatic hydrocarbons (PAHs) and low levels of dissolved oxygen (DO) were all incriminated as the initial stimulus behind biological invasion of pathogenic bacteria (Pseudomonas fluorescence) and yeast (C. albicans). Pathologically, fishes were dying from both respiratory and osmoregulatory failure induced by the severe damage of both gills and skin. It has been implied that such environmental pollutants have direct damaging effects on gills, skin and fins with consequent suppression of the skin's natural innate components. The adversely confronted immunological barriers were further exacerbated by the possible synergistic interactions of P. fluorescence dermotropic toxins followed by the secondary invasion of the pathogenic C. albicans.

Resistance to low-dose aspirin therapy among patients with acute coronary syndrome in relation to associated risk factors.

BACKGROUND: A substantial proportion of patients have recurrence of vascular events despite daily intake of low-dose aspirin therapy. Therefore, different patients may require different aspirin dosages to achieve complete inhibition of platelet function. OBJECTIVE: The aim of this work was to measure the response to low-dose aspirin therapy (150 mg/day) among patients with unstable angina or non-ST-segment elevation myocardial infarction and to find out whether titrating aspirin dosage to 300 mg/day, would provide a better therapeutic response in the resistant cases. Moreover, we also aimed to study any association between aspirin non-responsiveness and atherothrombotic risk factors. METHODS: The antiplatelet effect of 150 mg/day aspirin was studied prospectively in 50 consecutive patients with unstable angina or non-ST-segment elevation myocardial infarction. Platelet aggregation was measured using optical platelet aggregometry and serum thromboxane B(2) level. Aspirin resistance was defined as collagen (1 µg/mL) and adenosine diphosphate (ADP) (5 µmol/L)-induced platelet aggregation of ≥ 40% when compared with control values. Twenty healthy age- and sex-matched individuals were taken as a control group. All patients were subjected to complete medical history (risk factors, medications), thorough clinical examination, ECG, coronary angiography and laboratory investigations including: complete haemogram, coagulation, kidney, liver and lipid profiles, fasting blood glucose and glycated haemoglobin (HbA(1C) ). RESULTS: Eleven of 50 patients (22%) were found to be aspirin resistant. A highly significant difference was found between the mean values of ADP, collagen-induced platelet aggregation percentage and thromboxane B(2) level after aspirin 150 mg/day when compared with the corresponding mean values after aspirin 300 mg/day among the resistant patients (66 ± 7.01%, 62 ± 4.34% and 620 ± 64.58 pg/mL, respectively, vs. 26.87 ± 2.85%, 16.5 ± 3.8% and 77 ± 11.3 pg/mL) indicating enhanced response to aspirin after escalating the dose. The presence of atherothrombotic risk factors (hypertension, smoking, family history of ischaemic heart disease and previous MI) were not statistically different between aspirin-resistant and aspirin-sensitive patients. However, there was a highly significant difference between the aspirin sensitive and the resistant patients regarding the other risk factors (diabetes mellitus and dyslipidaemia) (P < 0.01). CONCLUSION: There is inter-individual variability in response to the antiplatelet effect of standard doses of aspirin (150, 300 mg/day). The response to aspirin 300 mg/day is enhanced in resistant patients when compared to 150 mg/day. There was a significant association between aspirin resistance and atherothrombotic risk factors (diabetes, hyperlipidaemia and obesity).

Safety of Mycoplasma gallisepticum vaccine strain 6/85 after backpassage in turkeys.

The objective of this research was to evaluate the safety of the 6/85 strain vaccine strain of Mycoplasma gallisepticum in turkeys by backpassing the vaccine strain up to 10 times by contact infection in turkeys and challenging turkeys with the resulting backpassaged strain. The vaccine strain, however, did not spread to in-contact turkeys, and it was necessary to reisolate the organism before challenging turkeys for the next passage. The challenge strain, therefore, was one that had been backpassaged four times in turkeys, with a total in vivo time in turkeys of 66 days. The backpassaged 6/85 vaccine strain was no different in pathogenicity than the original vaccine strain, except that at 10 days postchallenge, it was isolated in higher numbers from air sacs. Both the original 6/85 vaccine strain and the backpassaged strain were apathogenic in turkeys, except for a slightly increased diameter of the tracheal mucosa at 10 days postchallenge; at 20 days postchallenge the tracheal mucosal thickness was no different from that of controls.

Contraception in diabetic women: comparative metabolic study of Norplant, depot medroxyprogesterone acetate, low dose oral contraceptive pill and CuT380A.

OBJECTIVE: To evaluate the long-term intake of Norplant, depot medroxyprogesterone acetate (DMPA) and low dose oral contraceptive pill (OCs) on glycemic control, lipoprotein metabolism and coagulation profile in diabetic women. METHODS: Prospective comparative study including 80 uncomplicated controlled diabetic women. Twenty women allocated to each group. Clinical, metabolic and coagulation status were followed up at 3, 6 and 9 months' visits. RESULTS: Fasting blood sugar increased in OCs and DMPA users. Total cholesterol (TC) and LDL-cholesterol (LDL-C) decreased in all groups except DMPA where it increased. Triglyceride (TG) only increased in OCs group. HDL-cholesterol (HDL-C) increased with OCs and decreased with Norplant and DMPA. Compared to IUD users, significantly higher percentage TG and HDL-C and lower LDL-C were observed in OCs users, while DMPA users had significantly higher TC and LDL-C and lower HDL-C. Partial thromboplastin time was prolonged in Norplant users. CONCLUSION: In diabetics, Norplant results in minimal metabolic alterations followed by OCs while DMPA has unfavorable outcome.

The isolation of pathogenic fungi and actinomycetes from soil in Egypt.

140 soil samples from the Assiut governorate were examined for pathogenic fungi and actinomycetes. The paraffin-bait technique and a modified sodium citrate-utilizing procedure were used for recovery of Nocardia strains. Five isolations of N. brasiliensis were made by the sodium citrate method while 3 isolates were obtained by the other method. N. gypsoides was isolated for the first time, only the the modified method. It appears that the latter method suppresses to a great extent the growth of saprophytic fungi, hence increasing the possibility of the isolation of Nocardia spp. The effect of keratin enrichment on the isolation of dermatophytes from soil by the hair-bait technique was also investigated. Pretreatment of samples with dog hair or feathers increased the yield of isolates of Microsporum gypseum, Trichophyton terrestre and to a lesser extent, T. mentagrophytes, M. canis was recovered from soil only after its enrichment with dog hair. It is suggested that enrichment with other forms of keratinous material, either separately or in combination, might increase the recovery of keratinophilic fungi from soil.

The effect of the herbicide atrazine on rhizosphere microflora of broad bean plants, infested with Fusarium oxysporum f. fabae and Rhizoctonia solani.

The effect of the herbicide atrazine on Fusarium oxysporum f. fabae and Rhizoctonia solani, the causative agents of wilt and rot, respectively, as well as rhizosphere microflora of broad bean plants was studied. The herbicide was applied at intervals of 30, 20, 10, and 0 days before sowing. Atrazine application reduced both densities and per cent of infection of these two pathogenic fungi, R. solani, however, was sensitive to atrazine itself, while F. oxysporum was affected by atrazine by-products. Rhizosphere flora, i.e., total microbial flora, actinomycetes, phosphate-dissolving bacteria, and fungal flora, were not affected by atrazine, but were deleteriously reduced by its by-products at early stages of plant growth. However, rhizosphere flora attained the normal levels after atrazine by-products had completely disappeared from soil (1 month after application), except for actinomycetes. Therefore, it is recommended to apply atrazine within 20 days before sowing for weed control as well as for controlling wilt and root rot infestations.

Factors affecting the microbial and chemical composition of silage. IV. Effect of wilting on maize silage.

The effect of wilting on the microbial and chemical composition of ensiled maize plants was studied. Wilting stimulated high densities of lactic acid bacteria, with the decrease in counts of undesirable flora, i.e., yeasts, moulds, proteolytic and saccharolytic anaerobes, causing spoilage of silage. Moreover, wilting decreased the losses of dry matter, total acidity, and butyric acid content of silage. Accordingly, wilting proved to be a favourable treatment for the production of good quality silage from maize plants.

Changes in metabolic activities of Fusarium oxysporum f. fabae and Rhizoctonia solani in response to Dithan A-40 fungicide.

The effect of different concentrations of Dithan A-40 fungicide on the metabolic activities of the wilt fungus Fusarium oxysporum f. fabae and the root rot agent Rhizoctonia solani was studied. All toxicant concentrations reduced energy generation, total phosphorus and nitrogen content of both fungi. In addition, the toxicant caused a shift in free amino acids pool. As a result of these changes, the mycelium dry weight of both fungi was greatly reduced. R. solani was more sensitive to the toxic effect of Dithan A-40 than F. oxysporum.

Factors affecting the microbial and chemical composition of silage. III. Effect of urea additions on maize silage.

The effect of urea additions on the microbiological and chemical properties of silage, produced from young maize plants (Darawa stage), was studied. Urea treatments, i.e., 0.25%, 0.50%, 0.75%, and 1.00%, stimulated higher densities of the desired microorganisms than the control, while undesired organisms showed lower counts (proteolytic and saccharolytic anaerobes). Addition of 0.25 to 0.50% or urea resulted in the production of high quality silage with pleasant small and high nutritive value, as confirmed by the various microbiological and chemical analyses conducted. Higher levels (0.75 and 1.00%) of urea decreased the quality of the product.

Relation between the toxogenicity and pyogenicity of Corynebacterium ovis in experimentally infected mice.

Suspensions of Corynebacterium ovis subjected to physical and chemical treatment failed to kill inoculated mice but were able to produce sterile pyogenic lesions. It appears that the exotoxin is different from the pyogenic factor and that the latter is attached to a heat-stable substance in the bacterial cell. Mice immunised with antitoxin showed local non-spreading lesions when subsequenly inoculated with washed C ovis cells while unprotected control mice showed a spreading type of infection when similarly injected. Antitoxin did not prevent the formation of pus but hindered the spread of infection from the site of inoculation to the internal organs.