Suppression of inward-rectifying K+ channels KAT1 and AKT2 by dominant negative point mutations in the KAT1 alpha-subunit

Na(+)-glucose transport and transepithelial permeability were investigated during symptomatic acute cryptosporidiosis in newborn rats. The infection resulted in a significant (P < 0.01) decrease in the ileal short-circuit current and a nonsignificant fall in the transepithelial potential difference and conductance. In glucose-stimulated conditions, the rise in ileal short-circuit current and transepithelial permeability were significantly lower in Cryptosporidium parvum-infected rats than in controls (delta Isc = 3.24 +/- 1.21 microA.cm-2 vs delta Isc = 5.09 +/- 2.23 microA.cm-2 in infected and control animals, respectively; P < 0.001; delta PD = -0.35 +/- 0.13 mV vs delta PD = -0.44 +/- 0.14 mV for infected and control animals, respectively; P < 0.01). Electrical parameters were not affected by addition of the cyclooxygenase inhibitor indomethacin in either Cryptosporidium-infected newborn rats or controls. Horseradish peroxidase and mannitol flux studies demonstrated a significant decrease (P < 0.05) in transepithelial molecular permeability in infected enterocyte rats, HRP flux = 380, range 68-5570 ng.cm-2, and mannitol flux = 1.06, range, 0.34-1.44%.cm-2.min-1, compared with controls rats, HRP flux = 4446 range, 1121-124,363 ng.cm-2, and mannitol flux = 1.99, range, 0.57-5.09%.cm-2.min-1; P < 0.05. These effects could originate from C. parvum-induced alteration of intracellular trafficking of pinocytosis vesicles and therefore account for the decrease in permeability to solute and macromolecules, together with impaired transcellular nutrient transport, in suckling rats.     

Comment on the paper “Controlling intermetallic compound formation reaction between Sn and Ni-P by Zn addition” by X.F. Zhang, J.D. Guo, J.K. Shang, J. Alloys Compd. 479 (2009) 505–510

Zhang et al. recently reported about the formation of Ni₄(Sn,Zn) in the interlayer of a Sn–Zn/Ni(P) solder joint. This phase is claimed to be based on the binary Ni₄Sn phase. However, this phase as described in the literature by Mikulas and Thomassen, was ruled out for any existing phase diagram version. It could be proved that the diffraction pattern from Mikulas and Thomassen was composed of Ni and Ni₃Sn low-temperature phase. Thus the interpretation of their X-ray diffraction results is incorrect and the phase “Ni₄Sn” is an artefact. The indexing of Ni₄(Sn,Zn) by Zhang et al. is based on this artefact and therefore is incorrect, too. Furthermore, Tai et al. investigated IMC formation in Sn–3Ag–0.5Cu/Ni–8Zn–8P joints and could not observe any interdiffusion of Zn as stated by Zhang et al.     

Univariate statistical analysis of environmental (compositional) data: Problems and possibilities

For almost 30 years it has been known that compositional (closed) data have special geometrical properties. In environmental sciences, where the concentration of chemical elements in different sample materials is investigated, almost all datasets are compositional. In general, compositional data are parts of a whole which only give relative information. Data that sum up to a constant, e.g. 100 wt.%, 1,000,000 mg/kg are the best known example. It is widely neglected that the “closure” characteristic remains even if only one of all possible elements is measured, it is an inherent property of compositional data. No variable is free to vary independent of all the others.Existing transformations to “open” closed data are seldom applied. They are more complicated than a log transformation and the relationship to the original data unit is lost. Results obtained when using classical statistical techniques for data analysis appeared reasonable and the possible consequences of working with closed data were rarely questioned. Here the simple univariate case of data analysis is investigated. It can be demonstrated that data closure must be overcome prior to calculating even simple statistical measures like mean or standard deviation or plotting graphs of the data distribution, e.g. a histogram. Some measures like the standard deviation (or the variance) make no statistical sense with closed data and all statistical tests building on the standard deviation (or variance) will thus provide erroneous results if used with the original data.     

New developments in diagnosis and therapy of primary non-Hodgkin's lymphoma of the central nervous system

Primary central nervous system lymphomas (PCNSLs) are increasing in frequency both in immunocompetent and immunodeficient individuals. The majority of PCNSLs are high grade B cell lymphomas. In AIDS patients most tumors contain EBV genome. PCNSLs usually present as intracerebral, often deep-seated lesions half of which are multilocular. Less frequent are diffuse periventricular, exclusively leptomeningeal, ocular or spinal spread. On imaging PCNSLs show as contrast-enhancing lesions with relatively little perifocal edema. CSF protein is usually elevated. Malignant cells are present in 20-30% of cases. Demonstration of a monoclonal B cell population by immunocytology or FACS analysis may also be diagnostic. Once PCNSL is suspected extensive systemic evaluation is not useful. Instead, (stereotactic) biopsy of brain lesion(s) should be performed. Prior to biopsy, corticosteroids should be withheld as they may obscure diagnosis. Symptomatic edema or increased intracranial pressure should therefore initially be treated with osmotherapeutics. All immunodeficient patients should receive empiric anti-toxoplasmosis therapy for about 14 days prior to biopsy. AIDS patients with PCNSL survive 3 to 5 months (median) after whole brain irradiation and usually do not benefit from chemotherapy. Immunocompetent patients have a median survival of 12 to 18 months after whole brain irradiation alone, but a median survival of 33 to 43 months after combined radiochemotherapy using cytostatic drugs which penetrate the blood-brain barrier. Based on these encouraging results current concepts aim to intensify chemotherapy and to reduce or delay radiotherapy in the treatment of immunocompetent patients.     

Sheet gamma TiAl: Status and opportunities

Gamma TiAl alloys have attractive properties such as low density, high-temperature strength, and high modulus, oxidation, and burn resistance. As a result, these alloys have the potential to replace heavier superalloys in aircraft engine components. Gamma TiAl alloys were investigated in the 1950s but were too brittle for thermo-mechanical processing. However, interest in this class of material rekindled with several U.S. aerospace programs: the National Aerospace Plane, the Integrated High Performance Turbine Engine Technology, and Enabling Propulsion Materials/High Speed Civil Transport, as well as German hypersonic technology programs. Intense metallurgical and metal processing research during the last two decades led to significant progress in this area. As a result, gamma TiAl alloys are now available in all conventional product forms: ingots, forgings, extrusions, and sheets. This article reviews the current status of sheet gamma TiAl technology and its future opportunities. For more information, contact Gopal Das, Pratt & Whitney, 400 Main Street, E. Hartford, CT 06108 USA; (860) 557-1413; e-mail gopal.das@pw.utc.com.     

Screening of phenylalanine ammonia lyase in plant tissues,and retention of activity during dehydration

BACKGROUND: Oral therapy with phenylalanine ammonia lyase (PAL), naturally encapsulated in plant cells, may provide a potential alternative treatment for hyperphenylalaninemic patients, including those with phenylketonuria. Therefore different sources of plant tissue were investigated for PAL activity. RESULTS: Enzyme activity was highest in grain seedlings, with maximal enzyme activity in 7‐day‐old red spring wheat (Triticum aestivum L.) seedlings. The PAL activities of leaves and roots/endosperm of wheat seedlings were 11.90 ± 2.64 and 6.48 ± 1.59 µmol h^?1 g^?1 dry weight respectively. Three PAL‐related polypeptides with molecular weights of 74, 83 and 103 kDa were identified in wheat seedling leaf tissues, while only the 74 kDa polypeptide was detected in root/endosperm tissues. Dehydration was investigated as a method of concentrating PAL in wheat seedlings. Freeze‐drying was found to retain the most PAL activity (>90% recovery on a dry weight basis) compared with air drying and vacuum microwave drying for both leaf and root/endosperm samples. CONCLUSION: This study has led to a better understanding of PAL activity and stability in plant tissues and provides the basis for developing a natural plant preparation as a dietary supplement for the treatment of hyperphenylalaninemia. Copyright © 2007 Society of Chemical Industry     

Computing Fibers: A Novel Fiber for Intelligent Fabrics?

This communication describes a possible path for transition from a wearable computer to a fiber computer in which digital processing power is integrated directly into textiles via circuits on individual fibers. Three different classes of computing fiber substrate (active, passive, and intermediate) are discussed and some technologies for their manufacture are reviewed. It is shown here that with two of these techniques it is possible to develop new substrates for the semiconductor industry. Using an silicon‐on‐insulator (SOI) process, polycrystalline silicon fibers with a length of 42 mm have been successfully produced at NMRC in Ireland. These fibers are 35 μm wide and 1 μm thick. Silicon carbide (SiC) and silicon dioxide (SiO₂) endless fibers (subsequently cut in to 20 cm lengths) have also been produced by extrusion. After sintering, this method yielded polycrystalline SiC fibers and pure amorphous SiO₂ glass fibers. For many future applications, fiber computing appears to be a possible key to success. The computing power offered by such fibers may be combined with additional in‐ and output functions by weaving fiber‐based sensors and piezoelectric materials into textiles.