Widely tunable continuous-wave mid-infrared radiation (5.5-11 microm) by difference-frequency generation in LiInS2 crystal

The first demonstration, to the best of our knowledge, of continuous-wave (cw) difference-frequency generation (DFG) in LiInS2 crystal is reported. Wide spectral coverage (5.5-11.3 microm) has been obtained with angle and wavelength tuning for type II (eoe) critically phase-matched parametric interaction. The phase-matching conditions in cw DFG have been investigated, which allowed us to improve the Sellmeier parameters by use of a two-pole dispersion equation. An effective nonlinear coefficient deff = 6.9 +/- 0.8 pm/V has been determined at approximately 7 microm relative to the well-known nonlinear coefficient d36 of AgGaS2, which yields a power-conversion efficiency of approximately 12.4 microW/(W2 cm). We evaluated the high-resolution spectral characteristics of the DFG source by recording C2H2 and SO2 spectra.     

RESPIRATORY DEFICIENT MUTANTS OF BOTTOM BREWER'S YEAST. I. FREQUENCIES AND TYPES OF MUTANT IN VARIOUS STRAINS

Four strains of bottom brewer's yeast used in Czech breweries did not differ substantially from one another in their frequencies of spontaneous respiratory-deficient (RD) mutants as tested by the triphenyl tetrazolium chloride (TTC) overlay technique. These frequencies amounted to 1.1–1.4% of the total viable cell number after cultivation in bottom layers of wort. The strain which had the highest rate of aerobic growth gave a spontaneous mutation frequency of 0.5% in shaken cultures. In comparison with the TTC overlay technique, WL-Difco-agar with brom cresol green gave lower estimations of the frequency of production of spontaneous RD mutants. The RD mutants isolated can be divided into II groups on the basis of their cytochrome content (particularly cytochromes b and c) after aerobic growth. Of the 34 RD isolates tested, only 3 produced considerable numbers of revertants to respiratory sufficiency. These 3 mutants were derived from the same original strain, had the same cytochrome type, and had very slow growth rates. All RD mutants isolated had slower growth rates under aerobic conditions and reduced fermentation rates in static cultures in comparison with the parent types.     

METABOLIC QUOTIENTS OF RESPIRATION-DEFICIENT MUTANTS OF BREWER'S YEAST AND THE APPEARANCE OF A NEGATIVE PASTEUR EFFECT

Four industrial strains of bottom brewer's yeast and a group of their spontaneous respiration deficient (RD) mutants were tested for rates of metabolism of glucose and maltose under aerobic and anaerobic conditions. Q_o2 of all the RD mutants tested (26 isolates) ranged from 1·9 to 6·8 μl/mg yeast dry weight on glucose and was lowered to about one-half on maltose although the original strains had the same Q_o2 values on both sugars. No isolate showed any increase in glucose fermentation in aerobic conditions as compared with the original strains and the decrease of Pasteur effect found in certain isolates was always accompanied by a strong decrease of glycolysis in both aerobic and anaerobic conditions. Two mutants showed a strongly negative Pasteur effect, for their fermentation rates were higher in aerobic conditions than in anaerobic ones. Two other mutants showed a strong negative Pasteur effect only on maltose. The ratio of Q^N_2CO2 on glucose in most mutants was significantly lower than in their parental strains.     

Influence of genetic dissimilarity of mother and fetus on progesterone concentrations in pregnant mice and adaptive features of offspring

Concentrations of progesterone in blood plasma and tissue were studied in pregnant mice of strains BALB/cLac and C57BL/6J. Both intra- and interstrain mating and embryo transplantations were used as models of homo- and heterotopic pregnancy. On day 4 of heterotopic pregnancy, plasma progesterone concentrations of females of both strains were higher than those in females of both strains undergoing homotopic pregnancy. In addition, tissue progesterone content of hybrid embryos was higher than that of purebred embryos. Adrenocortical responses to social conflict as indicators of stress resistance were studied in progeny aged 2-3 months. There was a minimal increase in plasma glucocorticoid concentrations in heterotopic transplantants after 15 min pair-matching tests and 30 min crowding compared with those of other progeny, including purebred male mice of BALB/cLac and C57BL/6J strains, homotransplantants and reciprocal hybrids. Thus, genetic dissimilarity of mother and fetuses plays an important role in progesterone provision during pregnancy and also modifies development of progeny.     

A unified benchmarking and model-based framework for building QoS-aware streaming media services

A number of technology and workload trends motivate us to consider the appropriate resource allocation mechanisms and policies for streaming media services in shared cluster environments. We present MediaGuard – a model-based infrastructure for building streaming media services – that can efficiently determine the fraction of server resources required to support a particular client request over its expected lifetime. The proposed solution is based on a unified cost function that uses a single value to reflect overall resource requirements such as the CPU, disk, memory, and bandwidth necessary to support a particular media stream based on its bit rate and whether it is likely to be served from memory or disk. We design a novel, time-segment-based memory model of a media server to efficiently determine in linear time whether a request will incur memory or disk access when given the history of previous accesses and the behavior of the server's main memory file buffer cache. Using the MediaGuard framework, we design two media services: (1) an efficient and accurate admission control service for streaming media servers that accounts for the impact of the server's main memory file buffer cache, and (2) a shared streaming media hosting service that can efficiently allocate the predefined shares of server resources to the hosted media services, while providing performance isolation and QoS guarantees among the hosted services. Our evaluation shows that, relative to a pessimistic admission control policy that assumes that all content must be served from disk, MediaGuard (as well as services that are built using it) deliver a factor of two improvement in server throughput.     

A spatial discrepancy measure between voxel sets in brain imaging

Functional Magnetic Resonance Imaging serves to identify networks and regions in the brain engaged in various mental activities, represented as a set of voxels in the 3D image. It is important to be able to measure how similar two selected voxel sets are. The major flaw of the currently used correlation-based and overlap-based measures is that they disregard the spatial proximity of the selected voxel sets. Here, we propose a measure for comparing two voxel sets, called Spatial Discrepancy, based upon the average Hausdorff distance. We demonstrate that Spatial Discrepancy can detect genuine similarities and differences where other commonly used measures fail to do so. A simulation experiment was carried out where distorted copies of the same voxel sets were compared, varying the level of distortion. The experiment revealed that the proposed measure correlates better with the level of distortion than any of the other measures. Data from a 10-subject experiment were used to demonstrate the advantages of the Spatial Discrepancy measure in multi-subject studies.     

Geochemistry and mineralogy of platinum-group elements (PGE) in chromites from Centralnoye I, Polar Urals, Russia

The Polar Urals region of northern Russia is well known for large chromium(Cr)-bearing massifs with major chromite orebodies,including the Centralnoye I deposit in the Ray-lz ultramafic massif of the Ural ophiolite belt.New data on platinum(Pt)-group elements(PGE),geochemistry and mineralogy of the host dunite shows that the deposit has anomalous iridium(It)values.These values indicate the predom-inance of ruthenium-osmium-iridium(Ru-Os-lr)-bearing phases among the platinum-group mineral(PGM)assemblage that is typical of mantle-hosted chromite ores.Low Pt values in chromites and increased Pt values in host dunites might reflect the presence of cumulus PGM grains.The most abundant PGM tbund in the chromite is erlichmanite(up to 15 μm).Less common are cuproiridsite(up to 5 μm),irarsite(up to4-5 μm),and laurite(up to 4 μm).The predominant sulfide is heazlewoodite,in intergrowth with Ni--Fe alloys,sporadically with pentlandite,and rarely with pure nickel.Based on the average PGE values and esti-mated Cr-ore resources,the Centralnoye I deposit can be considered as an important resource of PGE.     

EPDM recycling assisted by γ-processing

The integration of waste ethylene–propylene–diene terpolymer (EPDM), containing carbon black into pristine EPDM can be achieved by γ-irradiation as a versatile procedure to process ethylene–propylene elastomers. The presence of acrylic acid in the material formulation allows the formation of intermolecular bridges by threefold increase in gel content. The possibility of achieving greater stability by the addition of acrylic acid in EPDM systems was analyzed. The start materials were EPDM containing 30 and 50 phr of EPDM powder loaded with 40 phr of carbon black aged by pre-exposure to electron beam irradiation. The advanced γ-irradiation exceeding 100 kGy represented the optimal radiation processing condition. Two procedures of chemiluminescence under isothermal and non-isothermal regimes for the evaluation of radiation stability were applied on γ-irradiated samples. The thermal strength of irradiated samples was characterized based on the radiolysis mechanism of EPDM. The variation in the activation energy required for the thermal oxidation of these samples and the modification in gel contents due to the gelation action of acrylic acid were presented for the validation of proposed recycling radiochemical technique. Charlesby–Pinner representation provided different values for the ratios between radiochemical yields of cross-linking and scission, proving that the presence of acrylic acid promoted the conversion of EPDM wastes into valuable materials.     

Mitochondrial Dysfunction and Chronic Inflammation in Polycystic Ovary Syndrome

Polycystic ovarian syndrome (PCOS) is the most common endocrine–metabolic disorder affecting a vast population worldwide; it is linked with anovulation, mitochondrial dysfunctions and hormonal disbalance. Mutations in mtDNA have been identified in PCOS patients and likely play an important role in PCOS aetiology and pathogenesis; however, their causative role in PCOS development requires further investigation. As a low-grade chronic inflammation disease, PCOS patients have permanently elevated levels of inflammatory markers (TNF-α, CRP, IL-6, IL-8, IL-18). In this review, we summarise recent data regarding the role of mtDNA mutations and mitochondrial malfunctions in PCOS pathogenesis. Furthermore, we discuss recent papers dedicated to the identification of novel biomarkers for early PCOS diagnosis. Finally, traditional and new mitochondria-targeted treatments are discussed. This review intends to emphasise the key role of oxidative stress and chronic inflammation in PCOS pathogenesis; however, the exact molecular mechanism is mostly unknown and requires further investigation.     

A Volatile Relationship: Profiling an Inter-Kingdom Dialogue Between two Plant Pathogens,Ralstonia Solanacearum and Aspergillus Flavus

Microbes in the rhizosphere have a suite of extracellular compounds, both primary and secondary, that communicate with other organisms in their immediate environment. Here, we describe a two-way volatile interaction between two widespread and economically important soil-borne pathogens of peanut, Aspergillus flavus and Ralstonia solanacearum, a fungus and bacterium, respectively. In response to A. flavus volatiles, R. solanacearum reduced production of the major virulence factor extracellular polysaccharide (EPS). In parallel, A. flavus responded to R. solanacearum volatiles by reducing conidia production, both on plates and on peanut seeds and by increasing aflatoxin production on peanut. Volatile profiling of these organisms using solid-phase micro-extraction gas chromatography mass spectroscopy (SPME-GCMS) provided a first glimpse at the compounds that may drive these interactions.