Microstructure and dispersion of Cu-TiC X master alloys into molten Cu and the relation to contact angle data

Cu-TiC _x composites have been made self-propagating high temperature synthesis of Cu-Ti-C mixtures. It was found that as the C/Ti ratio decreases, wetting of the carbide, by what is effectively a molten Cu-Ti alloy, is improved and the distribution of the carbides in the master-alloy becomes ideal for subsequent dispersion, i.e. discrete particles are formed. Increasing quantity of Cu in the reactants from 10 to 50 wt% Cu had a similar effect to decreasing the C/Ti ratio and enabled the size of the TiC _x particles to be varied in the approximate range 20–0.5 μm. Incorporation and dispersion of the master alloy into molten copper was possible when the C/Ti ratio in the products was below approximately 0.73, which agreed well with contact angle data in the literature.     

Adapting H.323 terminals in a service-oriented collaboration system

The Global Multimedia Collaboration System is designed to bridge H.323, Session Initiation Protocol, Access Grid clients, and 2.SG/3G cellular phones in audio-visual collaborations. One of its key components is the H.323 gateway, which lets H.323 terminals interact with other clients, providing complete conferencing control services. This system is designed to help scientists and students who have access only to H.323 and SIP endpoints or cellular phones with scientific collaboration in the high-end Access Grid environment.     

Fountains as urban furniture in historical urban structure and usage culture: Erzurum city case

Urban street furniture are the structural elements that vary depending on cultural features of countries or cities. These elements have a very important role in the view of adding a meaning to “city identify” and faciliting of the “society life”. The historical fountains as a street furniture widespread in Turkey. This historical street fountains do not exist anywhere except from Turkey.     

The Effects of High-Pressure Processing at Low and Subzero Temperatures on Inactivation of Microorganisms in Frozen and Unfrozen Beef Mince Inoculated with Escherichia coli Strain ATCC 25922

Frozen and unfrozen beef mince inoculated with Escherichia coli strain ATCC 25922 were exposed to a pressure of 300 MPa for 5 min at different temperatures (?10, ?5, 0, 10 and 20 °C). A maximum reduction of 1.5 log in total aerobic count (TAC) was obtained in unfrozen samples at ?5 °C, whereas at 20 °C, the reduction was only 0.6 log. Microbial inactivation in beef mince was enhanced by freezing the beef mince prior to pressurization. An average log reduction of 3.0 (SD?=?0.2) in both E. coli and TAC was obtained in frozen beef mince treated at ?5 °C. The highest bacterial reductions were observed in frozen samples. The extent of bacterial injury was substantially less in frozen samples than unfrozen samples, indicating that the damage inflicted on microorganisms in frozen beef mince by high pressure was irreversible. Lightness (L ^*), redness (a ^*) and yellowness (b ^*) values measured in accordance of Commission Internationale de l’Eclairage (CIE) for all the pressure-treated frozen and unfrozen samples differed slightly from unfrozen control samples (average total colour change, ΔE?=?6.1, SD?=?1.1). Water-holding capacity (WHC) measured by “high-pressure expressed moisture”, a new method proposed in this study, showed that freezing the samples prior to pressurization could increase WHC of minced beef. The results suggest that high-pressure processing could be used to make safer traditional raw minced meat products, such as steak tartare and cig kofte, a traditional Turkish dish made with minced beef, bulgur and spices.     

Penetration of oral and topical ciprofloxacin into human aqueous humor

PURPOSE: This study was planned to investigate the penetration of ciprofloxacin into aqueous humor following oral and topical application as a prophylactic antimicrobial agent. METHODS: Forty-six patients undergoing cataract surgery were randomly divided into two groups. In the first group, the patients received 500 mg oral ciprofloxacin eight hours before surgery and in the second, 5 drops of 0.3% ciprofloxacin were applied to the patients every twenty minutes, starting 100 minutes before the surgery. By paracentesis, aqueous samples were taken just before the operation so the interval between the first topical application and paracentesis was 100 minutes. RESULTS: The mean concentration of ciprofloxacin in aqueous humor was 0.63+/-0.29 microg/ml in the first group. The concentration was 0.69+/-0.30 microg/ml in the second group. Both of these mean concentrations were higher than the levels of MIC90 of S.aureus , S. epidermidis, P. aeruginosa and Gram (-) bacteriae. CONCLUSION: As a result, both topically and orally applied ciprofloxacin achieved a significant aqueous concentration. Each route studied might be suitable for surgical prophylaxis or treatment of infections.     

A study of adenosine treatment in experimental acute spinal cord injury. Effect on arachidonic acid metabolites

STUDY DESIGN: A prospective, randomized, blinded experimental trauma study. STUDY OBJECTIVE: The effect of adenosine on arachidonic acid metabolites and lipid peroxidation was investigated in induced spinal cord injury. SUMMARY OF BACKGROUND DATA: Effects of adenosine in ischemia-reperfusion models have been studied, but no studies of adenosine's effect on direct trauma to the spinal cord have been reported. METHODS: Thirty-seven adult Wistar albino rats were randomly divided into four groups and underwent laminectomy. Group 1 underwent a sham operation. Group 2 received an intravenous adenosine infusion of 100 micrograms/kg per minute for 30 minutes. In Group 3, a standard spinal cord trauma of 50 g.cm strength was established at the lower thoracic level with a "weight-drop" technique, and Group 4 received an infusion of adenosine (100 micrograms/kg per minute) for 30 minutes after the trauma. RESULTS: Tissue prostaglandin E2 activity was significantly higher in adenosine-treated trauma groups when compared with that in other groups (P < 0.0001). The difference in tissue leukotriene C4 activity between control and trauma groups was significant (P < 0.05). Adenosine infusion after trauma limited the increases in lipid peroxidation, with the difference approaching significance at P = 0.06. The structure of myelin was well preserved in the adenosine-treated trauma group. However, the changes were irreversible in severely damaged areas. CONCLUSION: After acute spinal cord trauma, intravenous adenosine infusion of 100 micrograms/kg per minute could attenuate progression to secondary injury, but adenosine alone was not effective yet.     

Separation and enrichment of gold(III) from environmental samples prior to its flame atomic absorption spectrometric determination

A simple and accurate method was developed for separation and enrichment of trace levels of gold in environmental samples. The method is based on the adsorption of Au(III)-diethyldithiocarbamate complex on Amberlite XAD-2000 resin prior to the analysis of gold by flame atomic absorption spectrometry after elution with 1 molL(-1) HNO3 in acetone. Some parameters including nitric acid concentration, eluent type, matrix ions, sample volume, sample flow rate and adsorption capacity were investigated on the recovery of gold(III). The recovery values for gold(III) and detection limit of gold were greater than 95% and 16.6 microgL(-1), respectively. The preconcentration factor was 200. The relative standard deviation of the method was <6%. The adsorption capacity of the resin was 12.3 mg g(-1). The validation of the presented procedure was checked by the analysis of CRM-SA-C Sandy Soil certified reference material. The presented procedure was applied to the determination of gold in some environmental samples.     

Homofermentative lactic acid bacteria of a traditional cheese, Comlek peyniri from Cappadocia region

Comlek peyniri is a typical artisanal cheese in Central Anatolia. This type of cheese was made by using the indigenous lactic acid bacteria (LAB) flora of cow or ewes' milk. Majority of the samples were taken from fresh cheese because the aim was to isolate homofermentative LAB. Initially 661 microbial isolates were obtained from 17 cheese samples. Only 107 were found to be homofermentative LAB. These isolates were selected and identified by using both phenotypic and molecular methods. Phenotypic identification included curd formation from skim milk, catalase test, Gram staining and light microscopy, growth at different temperatures and salt concentrations, arginine hydrolysis, gas production from glucose, and carbohydrate fermentation. Molecular identification was based on the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the 16S rRNA gene-ITS (internally transcribed spacer) region. By combining the phenotypic and molecular identification results, isolates belonging to each of the following genera were determined at species or subspecies level: 54 Lactococcus lactis subsp. lactis, 21 Enterococcus faecium, 3 Ec. faecalis, 2 Ec. durans, 10 Ec. sp., 15 Lactobacillus paracasei subsp. paracasei, and 2 Lb. casei strains. Technological characterisation was also performed by culturing each of the strains in UHT skim milk, and by monitoring pH change and lactic acid production at certain time intervals through the 24 h incubation. Results of the technological characterisation indicated that 33% of the isolates (35 strains) were capable of lowering the pH of UHT milk below 5.3 after 6 h incubation at 30 degrees C. Thirty four of these strains were Lc. lactis subsp. lactis, and only one was an Ec. faecium strain.     

Preparation of macroporous poly(acrylamide) hydrogels by radiation induced polymerization technique

Macroporous poly(acrylamide) [poly(AAm)] hydrogels were prepared by using poly(ethylene glycol) (PEG) with three different molecular weight as the pore-forming agent during the radiation induced polymerization reaction. Scanning electron microscope graphs reveal that the macroporous network structure of the hydrogels can be adjusted by applying different molecular weights of PEG during the polymerization reaction. The swelling ratios of the PEG-modified hydrogels were much higher than those for the same type of hydrogel prepared via traditional method. However, the pulsatile swelling behavior of the PEG-modified hydrogels in water and in acetone was affected slightly by the change in the amount of the PEG.