Gaugino condensation in an improved heterotic M-theory

Gaugino condensation is discussed in the context of a consistent new version of low energy heterotic M-theory. The four dimensional reduction of the theory is described, based on simple boson and fermion backgrounds. This is generalised to include gaugino condenstates and various background fluxes, some with non-trivial topology. It is found that condensate and quantised flux contributions to the four-dimensional superpotential contain no corrections due to the warping of the higher dimensional metric.Comment: 11 pages, 4 figures, LaTe

Novel metered aerosol valve

The design and performance of a new valving mechanism for portable pressurized spraying devices is described, where the propellant in the device is a safe gas (so-called compressed gas) propellant rather than the current liquefied gases all of which are either volatile organic compounds or greenhouse gases. The valve sprays a fixed volume of liquid when the spraying actuator is depressed, as is essential used medical sprays, such as pressurized metered dose inhalers and nasal sprays, and also for automatic (wall-mounted) aerosol delivery systems for air-fresheners, insecticides and disinfectants. For ‘compressed gas’ aerosol formats, there is no flash vaporization of propellant so that pumping liquid from a metering chamber and atomization to form a spray must be achieved entirely by designing some means of using the pumping action of the gas in the container to act upon the liquid in the metering chamber. The new design utilizes a loosely fitting spherical piston element and a simple arrangement of a concentric housing and a moveable valve stem, such that liquid flow paths between the different elements are automatically closed and opened in the correct time sequence when the valve stem is depressed and released. Spraying data show excellent repeatability of liquid sprayed per pulse throughout the lifetime of device and drop sizes that are acceptable for devices such as air-fresheners and nasal sprays. The valve has only one additional component compared with liquefied gas metered valves and can be straightforwardly injection moulded. As will be explained, previous attempts failed due to expense, complexity and unreliability. Keywords Aerosol valve, spray metering, insert, inhaler, air-freshene

Core-scale characterisation of flow in tight Arabian formations

Peer reviewedPublisher PD

Degradation of human kininogens with the release of kinin peptides by extracellular proteinases of Candida spp.

The secretion of proteolytic enzymes by pathogenic microorganisms is one of the most successful strategies used by pathogens to colonize and infect the host organism. The extracellular microbial proteinases can seriously deregulate the homeostatic proteolytic cascades of the host, including the kinin-forming system, repeatedly reported to he activated during bacterial infection. The current study assigns a kinin-releasing activity to secreted proteinases of Candida spp. yeasts, the major fungal pathogens of humans. Of several Candida species studied, C. parapsilosis and C. albicans in their invasive filamentous forms are shown to produce proteinases which most effectively degrade proteinaceous kinin precursors, the kininogens. These enzymes, classified as aspartyl proteinases, have the highest kininogen-degrading activity at low pH (approx. 3.5), but the associated production of bradykinin-related peptides from a small fraction of kininogen molecules is optimal at neutral pH (6.5). The peptides effectively interact with cellular B2-type kinin receptors. Moreover, kinin-related peptides capable of interacting with inflammation-induced B1-type receptors are also formed, but with a reversed pH dependence. The presented variability of the potential extracellular kinin production by secreted aspartyl proteinases of Candida spp. is consistent with the known adaptability of these opportunistic pathogens to different niches in the host organism

Antioxidant activity of extract from gamma irradiated guava (Psidium guajava L.) seeds

The objective this study was to study the antioxidant activity efficiency of extracts from irradiated defatted guava (Psidium guajava L.) seeds at dose levels of 0, 2, 4 and 6 kGy. The non-irradiated and irradiated defatted guava seeds samples were extracted with acetone: water: acetic acid (90:9.5:0.5). Immediately after irradiation, the antioxidant activity was studied. Gas chromatographic-Mass spectrum was applied to identify and quantify the constituents (%) of extracts and the amino acids composition was determined in all samples under investigation of defatted guava seeds powder. The measurements of the antioxidant activity, using a ?-carotene-linoleate model system and radical scavenging capacity effect on 2, 2-diphenyl-1- picrylhydrazyl (DPPH) radical, was determined in the extracts of non-irradiated and irradiated defatted guava seeds powder. Meanwhile, noodles (homemade strips macaroni) were prepared from blends of 72% wheat flour containing 0, 2.5, 5 and 7.5% levels of non-irradiated defatted guava seeds powder. The results showed that samples of extracts from non-irradiated and irradiated defatted guava seeds had contained a considerable total polyphenolic compounds and marked scavenging activity on DPHH radical. On the other hand , the gas chromatography (GC) and mass spectroscopy (MS) separation technique led to identification of 26 components the of extract non-irradiated and irradiated samples. Also, the data revealed that guava seeds powder samples under investigation passes the most important essential amino acids and for human health such as trace elements iron, zinc and manganese. Noodles prepared from 2.5% level of guava seeds powder-wheat flour blend had high acceptable quality. Thus, guava seeds, a waste from guava industry can be utilized improved nutritional properties of noodles or used its extracts as natural antioxidant in food industry field. Key words: Guava Seeds/ Antioxidant/ Extract/ Gamma irradiation

Selected 2017 Highlights in Congenital Cardiac Anesthesia

This article is a review of the highlights of pertinent literature published during the 12 months of 2017, which is of interest to the congenital cardiac anesthesiologist. Following a search of the US National Library of Medicine PubMed database, several topics emerged where significant contributions were made in 2017, and that the authors of this manuscript felt were noteworthy to be summarized in this review: Training in pediatric cardiac anesthesia, the costs of congenital heart disease (CHD), catheter versus surgical intervention for CHD, cerebral oxygen saturation in CHD, and mechanical circulatory support in children

Two Chromatographic Methods for the Determination of Some Antimigraine Drugs

Two stability indicating chromatographic methods were proposed for the determination of almotriptan, eletriptan, and rizatriptan, in presence of their acid degradation products. The first method is a quantitative densitometric thin layer chromatography. The developing systems were; acetonitrile: methanol: dichloromethane: ammonia (10:6:3:1 v/v), ethyl acetate: methanol: ammonia (15:4:1 v/v), and methanol: acetonitrile: ammonia (9:4:1 v/v) for almotriptan, eletriptan and rizatriptan respectively. The TLC plates were scanned at 235 nm. Linear relationships were obtained over concentration ranges (5–50 μg/spot) for almotriptan and rizatriptan, and (5–60 μg/spot) for eletriptan. The second method based on the separation and determination of the studied drugs, using RP-HPLC technique. The separation was achieved on C18 Hypersil column, elution was carried out using phosphate buffer pH 3: methanol: acetonitrile (2: 1:1 v/v) at flow rate 2 mL/min and UV detection at 235 nm. Linear relationships were obtained over concentration ranges (10–200 μg/mL) for almotriptan and eletriptan, and (10–180 μg/mL) for rizatriptan. The chromatographic methods were successfully applied for the determination of each of the studied drugs in pure form, tablet form, and in laboratory prepared mixtures with their acid degradation products

A Scanning Electron Microscopic Study of the Chick Chorioallantoic Membrane: Cell Death and the Involvement of Oxygen Free Radicals

Cell death is a normal feature within the chick chorioallantoic membrane, occurring principally between days 10 and 14 of incubation. Samples of chorioallantoic membrane were obtained on days 6, 8, 10, 12 and 14 of incubation, after the creation of artificial air chambers on day 3. These were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) after staining for acid phosphatase activity, and by light microscopy after demonstrating oxygen free radicals with nitro blue tetrazolium. On day 6, small defects in the plasmalemma, approximately 200 nm in diameter, could be seen by SEM. A sequence of events leading to complete destruction of the plasmalemma, with exposure of the nucleus and other cytoplasmic organelles, could be traced, and by day 8 the membrane was a mosaic of healthy cells and others in various stages of degeneration. TEM revealed that acid phosphatase activity was confined to the golgi apparatus and associated vesicles even in advanced stages of degeneration. By comparison, oxygen free radicals were demonstrated in individual cells from day 6 onwards. Application of superoxide dismutase and catalase to the epithelium using a nebuliser spray significantly reduced the amount of cell death seen by scanning microscopy on day 12. It is concluded that oxygen free radicals may mediate cell death in the chorioallantoic membrane