Fourier transform infrared analysis of gas composition in low-volume light bulbs

Fourier transform infrared spectroscopy has been used for in situ analysis of HBr, CH3Br, and CO within light bulbs at different stages of burning time. The interference fringes originated in the quartz walls of the bulbs have been eliminated by different methods. The NIPALS procedure yielded higher S/N ratio than the fringe-elimination method applied. The CO and HBr showed time-dependent concentration changes during the burning period. The maximum CO concentration (approximately 6 ppm) was detected after 30-50 s of burning time, and then it practically burned out after 5 h. The HBr concentration increased in the first 3 min of burning, and then its concentration stabilized at a 10-15 ppm level. After 5 s of illumination, the CH3Br concentration became undetectable.     

Effect of galactose and sugar substitutes on blood insulin levels in normal and obese individuals

Eighteen male patients between the ages of 25 and 50 were given on a double blind randomized basis (A) 40 gms. galactose (B) 50 gms. arabinogalactan and 0.11 gm. sodium saccharin (C) 2 gm. methyl cellulose and 0.083 gm. sodium saccharin and (D) 4 gm. galactose, all in 200 ml water. Blood glucose, galactose and insulin levels were determined during a six hour period before and after ingestion. The three first mentioned solutions tasted equally sweet, the fourth was essentially tasteless. None of these feedings altered plasma insulin or glucose levels. It appears that in contrast to other conclusions reached by earlier investigators sweet taste is unable to induce insulin secretion through neurogenic pathways.     

Temperature-Dependent Re-alignment of the Short Multifunctional Peptide BP100 in Membranes Revealed by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations

BP100 is a cationic undecamer peptide with antimicrobial and cell-penetrating activities. The orientation of this amphiphilic α-helix in lipid bilayers was examined under numerous conditions using solid-state ¹⁹F, ¹⁵N and ²H NMR. At high temperatures in saturated phosphatidylcholine lipids, BP100 lies flat on the membrane surface, as expected. Upon lowering the temperature towards the lipid phase transition, the helix is found to flip into an upright transmembrane orientation. In thin bilayers, this inserted state was stable at low peptide concentration, but thicker membranes required higher peptide concentrations. In the presence of lysolipids, the inserted state prevailed even at high temperature. Molecular dynamics simulations suggest that BP100 monomer insertion can be stabilized by snorkeling lysine side chains. These results demonstrate that even a very short helix like BP100 can span (and thereby penetrate through) a cellular membrane under suitable conditions.     

Structure‐Based Mechanism of Oleate Hydratase from Elizabethkingia meningoseptica

Hydratases provide access to secondary and tertiary alcohols by regio‐ and/or stereospecifically adding water to carbon‐carbon double bonds. Thereby, hydroxy groups are introduced without the need for costly cofactor recycling, and that makes this approach highly interesting on an industrial scale. Here we present the first crystal structure of a recombinant oleate hydratase originating from Elizabethkingia meningoseptica in the presence of flavin adenine dinucleotide (FAD). A structure‐based mutagenesis study targeting active site residues identified E122 and Y241 as crucial for the activation of a water molecule and for protonation of the double bond, respectively. Moreover, we also observed that two‐electron reduction of FAD results in a sevenfold increase in the substrate hydration rate. We propose the first reaction mechanism for this enzyme class that explains the requirement for the flavin cofactor and the involvement of conserved amino acid residues in this regio‐ and stereoselective hydration.     

Near-field and far-field prediction of quasi-optical grid arrays

Field profiles, equivalent isotropic radiated power (EIRP), beamwidth, and sidelobe levels of a quasi-optical power-combining grid amplifier structure are obtained using a whole-field electromagnetic analysis of a finite structure. This is efficiently obtained using a mixed spectral- and spatial-domain method-of-moments technique. It is seen that edge effects can have a significant effect on system performance     

Formation and characterization of 1, 5-diphosphono-pentane films on polycrystalline zinc substrates

Investigation on time-dependent layer formation was performed on high purity polycrystalline zinc surface in reaction with aqueous solution of 1, 5-diphosphono-pentane (DPP) at room temperature. Film evolution was characterized by X-ray photoelectron spectroscopy, contact angle, atomic force microscopy, glow discharge optical emission spectroscopy and detailed infrared reflection absorption spectroscopy measurements. Development of a partly crystalline zinc-diphosphono-pentane conversion layer of increasing thickness with time was determined by consistent evaluation of the results. The formed layers turned the hydrophobic zinc surface to hydrophilic. The conversion-type interaction of diphosphonic acid compounds with the oxidized zinc surface resulting in zinc-diphosphonate salt was unambiguously justified by XPS and GD-OES analysis.The corrosion behaviour of the coated zinc substrate was studied using electrochemical impedance spectroscopy (EIS). The formed layers show significant protective effect in sodium-sulphate solutions. It was shown, that under the applied conditions, a 4 h treatment is necessary to obtain 75% protection efficiency after 4 h of immersion into the Na₂SO₄.     

A parametric study of the hydro-support

A mathematical model for a new type of navigation lock-gate support, the hydro-support, is presented. The hydro-support is a hydrostatic bearing, elastically connected to the lock-gate by a rubber hinge and sliding on an elastic polymer track. The model incorporates the pertinent physical aspects of the hydro-support, including the elastic deformation of the track, the bearing and the rubber hinge and the mixed lubrication between the bearing and the track. A calculation using this model on a typical hydro-support shows the contribution of the load carried by contact on the total load and the resulting increase of the friction forces.     

High Speed Quantum Key Distribution Over Optical Fiber Network System

The National Institute of Standards and Technology (NIST) has developed a number of complete fiber-based high-speed quantum key distribution (QKD) systems that includes an 850 nm QKD system for a local area network (LAN), a 1310 nm QKD system for a metropolitan area network (MAN), and a 3-node quantum network controlled by a network manager. This paper discusses the key techniques used to implement these systems, which include polarization recovery, noise reduction, frequency up-conversion detection based on a periodically polled lithium nitrate (PPLN) waveguide, custom high-speed data handling boards and quantum network management. Using our quantum network, a QKD secured video surveillance application has been demonstrated. Our intention is to show the feasibility and sophistication of QKD systems based on current technology.     

Immunohistochemical analysis of 1,25-dihydroxyvitamin D3 receptor in cervical carcinoma

The immunohistochemical localization and expression of 1,25-dihydroxyvitamin D3 receptors (VDR) has been investigated in normal human cervical tissue (n = 15) and in cervical carcinomas (n = 23). VDR immunoreactivity (monoclonal antibody 9A7gamma) was compared with the staining patterns of transglutaminase K, cytokeratin 10 and Ki-67 in these tumours. Moderate to strong nuclear immunoreactivity for VDR was detected in almost all cervical carcinomas analysed. VDR staining was homogeneous, with no visual differences between individual tumour cells. Some 60% of normal cervical tissues revealed weak immunoreactivity for VDR. In normal cervical tissue, nuclear VDR staining was confined to the lower cervical layers, predominantly to the basal cell layer. Both the intensity of VDR immunostaining and the number of VDR-positive cells were up-regulated in cervical carcinomas compared with normal cervical tissue. No visual correlation was found for the coexpression of VDR with markers of proliferation and differentiation. Our findings indicate that: (1) cervical tissue may be a new target organ for therapeutically applied vitamin D analogues; (2) VDR is up-regulated at the protein level in cervical carcinomas compared with normal cervical tissue; (3) up-regulation of VDR in cervical carcinoma is induced not exclusively by alterations in epithelial differentiation or proliferation, but by different, unknown mechanisms; and (4) calcitriol and new vitamin D analogues exerting fewer calcaemic side-effects may be promising new drugs for the treatment or chemoprevention of metastasizing cervical carcinomas as well as of cervical precancerous lesions.