Resonant Inelastic X-Ray Scattering Reveals Hidden Local Transitions of the Aqueous OH Radical.

Resonant inelastic x-ray scattering (RIXS) provides remarkable opportunities to interrogate ultrafast dynamics in liquids. Here we use RIXS to study the fundamentally and practically important hydroxyl radical in liquid water, OH(aq). Impulsive ionization of pure liquid water produced a short-lived population of OH(aq), which was probed using femtosecond x-rays from an x-ray free-electron laser. We find that RIXS reveals localized electronic transitions that are masked in the ultraviolet absorption spectrum by strong charge-transfer transitions-thus providing a means to investigate the evolving electronic structure and reactivity of the hydroxyl radical in aqueous and heterogeneous environments. First-principles calculations provide interpretation of the main spectral features.

Observation of the fastest chemical processes in the radiolysis of water.

Elementary processes associated with ionization of liquid water provide a framework for understanding radiation-matter interactions in chemistry and biology. Although numerous studies have been conducted on the dynamics of the hydrated electron, its partner arising from ionization of liquid water, H2O+, remains elusive. We used tunable femtosecond soft x-ray pulses from an x-ray free electron laser to reveal the dynamics of the valence hole created by strong-field ionization and to track the primary proton transfer reaction giving rise to the formation of OH. The isolated resonance associated with the valence hole (H2O+/OH) enabled straightforward detection. Molecular dynamics simulations revealed that the x-ray spectra are sensitive to structural dynamics at the ionization site. We found signatures of hydrated-electron dynamics in the x-ray spectrum.

A comparison of 2 evaporative cooling systems on a commercial dairy farm in Saudi Arabia.

Efficacy of 2 cooling systems (Korral Kool, KK, Korral Kool Inc., Mesa, AZ; FlipFan dairy system, FF, Schaefer Ventilation Equipment LLC, Sauk Rapids, MN) was estimated utilizing 400 multiparous Holstein dairy cows randomly assigned to 1 of 4 cooled California-style shade pens (2 shade pens per cooling system). Each shaded pen contained 100 cows (days in milk=58±39, milk production=56±18 kg/d, and lactation=3±1). Production data (milk yield and reproductive performance) were collected during 3mo (June-August, 2013) and physiological responses (core body temperature, respiration rates, surface temperatures, and resting time) were measured in June and July to estimate responses of cows to the 2 different cooling systems. Water and electricity consumption were recorded for each system. Cows in the KK system displayed slightly lower respiration rates in the month of June and lower surface temperatures in June and July. However, no differences were observed in the core body temperature of cows, resting time, feed intake, milk yield, services/cow, and conception rate between systems. The FF system used less water and electricity during this study. In conclusion, both cooling systems (KK and FF) were effective in mitigating the negative effects of heat stress on cows housed in arid environments, whereas the FF system consumed less water and electricity and did not require use of curtains on the shade structure.

Set-up for broadband Fourier-transform multidimensional electronic spectroscopy.

We present a compact passively phase-stabilized ultra-broadband 2D Fourier transform setup. A gas (argon)-filled hollow core fiber pumped by an amplified Ti:Al2O3 laser is used as a light source providing spectral range spanning from 420 to 900 nm. Sub-10-fs pulses were obtained using a deformable mirror-based pulse shaper. We probe the nonlinear response of Rhodamine 101 using 90 nm bandwidth and resolve vibrational coherences of 150 fs period in the ground state.

Frequency of intestinal parasitic infection among children in Hadhramout governorate (Yemen).

Six hundred children from urban and rural regions of Hadhramout governorate were examined targeted for the detection of intestinal parasites during the year 2009. The main infective parasites prevailed in children were Gardia lamblia (19.17%), Entamoeba histolytica (16.83%), Ascaris lumbricoides (15.83%), Trichuris trichiura (2.33%), Hymenolepis nana (2.33%), Taenia saginata (1.50%) and Schistosoma mansoni (0.67%). Besides, infections were accompanied by different symptoms as diarrhea (43.5%), abdominal pain (23.3%), abdominal distention (17.3%), constipation (9.1%), nausea and vomiting (8.02%) and fever (5.1%). The parasitosis reflected the hygienic problems and their influence on public health of Hadhramout.

Urinary tract infection among pregnant women in Al-Mukalla district, Yemen.

Urinary tract infection (UTI) is a common problem in pregnant woman. This study examined the frequency of UTI in 137 pregnant women attending Al Mukalla maternity hospital from January to June 2002. Urine samples were examined for UTI microscopically and by culture, and sensitivity tests were done for the organisms isolated using a range of antibiotics. Information on age, trimester, parity and number of pregnancies were also collected for each woman. This study showed that 30% of the women suffered from UTI; Escherichia coli was the most frequently isolated organism (41.5%), and it was highly susceptible to chloramphenicol, ciprofloxacin, ceftizoxime and amikacin. Of the variables examined, 53.7% of the infected women were in the age group 15-24 years, 48.8% were in their 3rd trimester and 75.6% had 1-3 children.

Urinary tract infection among pregnant women in Al-Mukalla district, Yemen

Urinary tract infection [UTI] is a common problem in pregnant woman. This study examined the frequency of UTI in 137 pregnant women attending Al Mukalla maternity hospital from January to June 2002. Urine samples were examined for UTI microscopically and by culture, and sensitivity tests were done for the organisms isolated using a range of antibiotics. Information on age, trimester, parity and number of pregnancies were also collected for each woman. This study showed that 30% of the women suffered from UTI; Escherichia coli was the most frequently isolated organism [41.5%], and it was highly susceptible to chloramphenicol, ciprofloxacin, ceftizoxime and amikacin. Of the variables examined, 53.7% of the infected women were in the age group 15-24 years, 48.8% were in their 3rd trimester and 75.6% had 1-3 children

Myosin Va bound to phagosomes binds to F-actin and delays microtubule-dependent motility.

We established a light microscopy-based assay that reconstitutes the binding of phagosomes purified from mouse macrophages to preassembled F-actin in vitro. Both endogenous myosin Va from mouse macrophages and exogenous myosin Va from chicken brain stimulated the phagosome-F-actin interaction. Myosin Va association with phagosomes correlated with their ability to bind F-actin in an ATP-regulated manner and antibodies to myosin Va specifically blocked the ATP-sensitive phagosome binding to F-actin. The uptake and retrograde transport of phagosomes from the periphery to the center of cells in bone marrow macrophages was observed in both normal mice and mice homozygous for the dilute-lethal spontaneous mutation (myosin Va null). However, in dilute-lethal macrophages the accumulation of phagosomes in the perinuclear region occurred twofold faster than in normal macrophages. Motion analysis revealed saltatory phagosome movement with temporarily reversed direction in normal macrophages, whereas almost no reversals in direction were observed in dilute-lethal macrophages. These observations demonstrate that myosin Va mediates phagosome binding to F-actin, resulting in a delay in microtubule-dependent retrograde phagosome movement toward the cell center. We propose an "antagonistic/cooperative mechanism" to explain the saltatory phagosome movement toward the cell center in normal macrophages.

Persistence of a clone of methicillin-resistant Staphylococcus aureus in a burns unit.

A total of 128 MRSA isolates from a burns unit in 1992 and 1997 was studied by resistotyping, plasmid analysis and pulsed-field gel electrophoresis (PFGE) of SmaI-digested chromosomal DNA to ascertain whether a clone of MRSA had persisted in the unit or whether different clones had been introduced at different times. All the MRSA isolates produced beta-lactamase and had high MICs to methicillin (>256 mg/L). All were resistant to tetracycline, kanamycin, cadmium acetate and mercuric chloride. Most were resistant to gentamicin, neomycin, erythromycin, chloramphenicol, trimethoprim, ciprofloxacin, propamidine isethionate and ethidium bromide, and were susceptible to minocycline, vancomycin and teicoplanin. None of the 1992 isolates was resistant to mupirocin, but 56% and 19% of the 1997 isolates expressed high- and low-level mupirocin resistance, respectively. Many of the 1997 isolates had acquired a 38-kb plasmid encoding high-level mupirocin resistance. The 1992 isolates had two main PFGE patterns; 82% of them belonged to PFGE pattern 1. The 1997 isolates had PFGE pattern 1, the same as the majority of the 1992 isolates. All MRSA isolates from both years carried the mecA gene in the same SmaI fragment. These findings demonstrated that a clone of MRSA that was prevalentin the burns unit in 1992 had persisted and became the predominant clone in 1997.

Rapid detection of methicillin resistance in staphylococci using a slide latex agglutination kit.

The slide latex agglutination test, MRSA-Screen, was compared with the mecA polymerase chain reaction (PCR) and traditional susceptibility test methods for the detection of methicillin resistance in Staphylococcus aureus and coagulase-negative staphylococci. The MRSA-Screen test detected the same number of methicillin-resistant S. aureus as the mecA PCR and the traditional susceptibility tests. It correctly identified all 21 methicillin-susceptible S. aureus as being sensitive. It also produced the same result as the mecA PCR in identifying a methicillin-resistant S. aureus among six isolates classified as borderline resistant by traditional susceptibility tests. The MRSA-Screen test and mecA PCR detected methicillin resistance in 10 and 15 of 17 methicillin-resistant coagulase-negative staphylococci, respectively. From these results, it is concluded that the MRSA-Screen is a very accurate, reliable and rapid method of detecting methicillin resistance in S. aureus and is suitable for use in clinical microbiology laboratories. Further study of its use in detecting methicillin resistance in coagulase-negative staphylococci is required.

Equilibrium Adsorption Studies of Some Aromatic Pollutants from Dilute Aqueous Solutions on Activated Carbon at Different Temperatures

Aqueous solutions of phenol, p-chlorophenol, and p-nitrophenol have been used to determine the adsorption isotherm for single solute systems on activated carbon at different temperatures. The experimental program has been conducted to investigate the influence of concentration and temperature. All the reported equilibrium isotherm equations have been tried on present and published experimental data. A generalized isotherm equation which was proposed by Khan et al. (6, 10) and tested for bi-solute adsorption data has been modified for single-solute system. The temperature dependency has also been incorporated into a generalized equation. It has been noticed that the Radke and Prausnitz (7) and generalized isotherm equations could represent the entire data with a minimum average percentage error. The influence of different adsorbents, sorbate concentrations, and pH of aqueous solutions has also been discussed in detail. The temperature dependency has been investigated using both the Dubinin-Astakov (13) and the modified generalized equation. The generalized equation describes the experimental and published data adequately and provides a single value of differential molar heat of adsorption, DeltaHads, for a single solute adsorption system. The Dubinin-Astakov isotherm equation has shown an increasing trend of DeltaHads as the loading of adsorbent has increased. Copyright 1997 Academic Press. Copyright 1997Academic Press

Mass transfer resistance in ASFF reactors for waste water treatment.

Analysis of mass transfer resistances was performed for an aerated submerged fixed-film reactor (ASFF) for the treatment of waste water containing a mixture of sucrose and ammonia. Both external and internal mass transfer resistances were considered in the analysis, and characterized as a function of feed flow-rate and concentration. Results show that, over a certain operating regime, external mass transfer resistance in the system was greater for sucrose removal than ammonia. This is because the reaction rates for carbon removal were much larger than those of nitrogen. As a result, existence of any form of mass transfer resistance caused by inadequate mixing or diffusion limitations, strongly affects the overall removal rates of carbon more than nitrogen. Effects of the internal måss transfer resistance were virtually non-existent for ammonia removal. This behaviour was found over two orders of magnitude range for the effective diffusivity for ammonia, and one order of magnitude for the film specific surface area. However, over the same parameters' range, it is found that sucrose removal was strongly affected upon lowering its effective diffusivity and increasing the film specific surface area.

Levels of trihalomethanes in the blended water of Bahrain.

The distribution of trihalomethanes in the water of the two main power stations and the 10 blending stations in Bahrain has been studied. Total trihalomethanes in the drinking water averaged 2.95 micrograms/l. Average concentrations (microgram/l) of individual compounds were: CHBr3, 2.17 +/- 0.3; CHBr2Cl, 0.48 +/- 0.14; CHBrCl2, 0.30 +/- 0.13.