Substrate-Specific Inhibition Constants for Phospholipase A2 Acting on Unique Phospholipid Substrates in Mixed Micelles and Membranes Using Lipidomics.

Assaying lipolytic enzymes is extremely challenging because they act on water-insoluble lipid substrates, which are normally components of micelles, vesicles, and cellular membranes. We extended a new lipidomics-based liquid chromatographic-mass spectrometric assay for phospholipases A2 to perform inhibition analysis using a variety of commercially available synthetic and natural phospholipids as substrates. Potent and selective inhibitors of three recombinant human enzymes, including cytosolic, calcium-independent, and secreted phospholipases A2 were used to establish and validate this assay. This is a novel use of dose-response curves with a mixture of phospholipid substrates, not previously feasible using traditional radioactive assays. The new application of lipidomics to developing assays for lipolytic enzymes revolutionizes in vitro testing for the discovery of potent and selective inhibitors using mixtures of membranelike substrates

Substrate-Dependent Allosteric Regulation in Cytochrome P450cam (CYP101A1)

Various biophysical methods have provided evidence of a second substrate binding site in the well-studied cytochrome P450cam, although the location and biological relevance of this site has remained elusive. A related question is how substrate and product binding and egress occurs. While many active site access channels have been hypothesized, only one, channel 1, has been experimentally validated. In this study, molecular dynamics simulations reveal an allosteric site related to substrate binding and product egress. The remote allosteric site opens channel 1 and primes the formation of a new channel that is roughly perpendicular to channel 1. Substrate entry to the active site via channel 1 as well as substrate/product egress via channel 2 is observed after binding of a second molecule of substrate to the allosteric site, indicating cooperativity between these two sites. These results are consistent with and bring together many early and recent experimental results to reveal a dynamic interplay between a weak allosteric site and substrate binding to the active site that controls P450cam activity

Controlled substrate cooling improves reproducibility of vapor deposited semiconductor composites

Improved substrate holder preferentially provides more uniform substrate cooling and increases the proportion of vapor flowing over the substrate during growth. Nitrogen gas is constricted in the substrate holder to cool the substrate

Half-mode substrate-integrated-waveguide cavity-backed slot antenna on cork substrate

A wideband half-mode substrate-integrated-waveguide cavity-backed slot antenna covering all Unlicensed National Information Infrastructure (U-NII) radio bands (5.15-5.85 GHz) is designed, fabricated, and validated. By a half-mode implementation of a multimoded cavity with nonresonant slot, a compact ultrawideband antenna is obtained with very stable radiation characteristics, owing to the excellent antenna/platform isolation. Cork material is applied as antenna substrate, making the proposed antenna suitable for integration into floors or walls. In free-space conditions, an impedance bandwidth of 1.30 GHz (23.7%), a radiation efficiency of 85%, a front-to-back ratio of 15.0 dB, and a maximum gain of 4.3 dBi at 5.50 GHz are measured. Performance is also validated when the antenna is deployed on various dielectric or conducting platforms and underneath different dielectric superstrates. Only the latter slightly detunes the antenna's impedance bandwidth. Yet, the complete frequency band of interest remains covered, owing to additional design margins incorporated in the requirements. Its compactness, unobtrusive integration potential, and stable high performance in different environments make this antenna topology an ideal candidate for Internet of Things applications

Method and apparatus for coating substrates using a laser

Metal substrates, preferably of titanium and titanium alloys, are coated by alloying or forming TiN on a substrate surface. A laser beam strikes the surface of a moving substrate in the presence of purified nitrogen gas. A small area of the substrate surface is quickly heated without melting. This heated area reacts with the nitrogen to form a solid solution. The alloying or formation of TiN occurs by diffusion of nitrogen into the titanium. Only the surface layer of the substrate is heated because of the high power density of the laser beam and short exposure time. The bulk of the substrate is not affected, and melting of the substrate is avoided because it would be detrimental

Pattern-induced anchoring transitions in nematic liquid crystals

In this paper we revisit the problem of a nematic liquid crystal in contact with patterned substrates. The substrate is modelled as a periodic array of parallel infinite grooves of well-defined cross section sculpted on a chemically homogeneous substrate which favors local homeotropic anchoring of the nematic. We consider three cases: a sawtooth, a crenellated and a sinusoidal substrate. We analyse this problem within the modified Frank-Oseen formalism. We argue that, for substrate periodicities much larger than the extrapolation length, the existence of different nematic textures with distinct far-field orientations, as well as the anchoring transitions between them, are associated with the presence of topological defects either on or close to the substrate. For the sawtooth and sinusoidal case, we observe a homeotropic to planar anchoring transition as the substrate roughness is increased. On the other hand, a homeotropic to oblique anchoring transition is observed for crenellated substrates. In this case, the anchoring phase diagram shows a complex dependence on the substrate roughness and substrate anchoring strength.Comment: 36 pages, 15 figures, revised version submitted to Journal of Physics: Condensed Matte

A 77GHz on-chip microstrip patch antenna with suppressed surface wave using EBG substrate

This paper presents the design of a patch antenna with suppressed surface waves by means of applying an electromagnetic band-gap structure. Establishing th e antenna on high dielectric substrate such as Silicon makes it possible to integrate the antenna with RFIC active component and circuitry. However, the performance (gain and radiation pattern) of antenna will be degraded due to the presence of surface waves on a thick dielectric substrate. It is possible to des ign an engineered substrate that filters out the surface wave around the frequency of interest. Moreover, having high dielectric substrate will localize EM wave to substrate and hence reduce antenna gain. For this problem, available silicon etching technology is used to remove the substrate right under the patch and have a locally low dielectric constant substrate underneath the antenn a. Proposed microstrip antenna resonates at 77GHz with 7dB realized gain which can be used in array for Automotive Radar purposes. Simulation results show great improvement in radiation pattern and 3dB increase in antenna's broadside gain in comparison with antenna on normal substrate

Devices Having Compliant Wafer-level Input/output Interconnections And Packages Using Pillars And Methods Of Fabrication Thereof

Devices having one or more of the following: an input/output (I/O) interconnect system, an optical I/O interconnect, an electrical I/O interconnect, a radio frequency I/O interconnect, are disclosed. A representative I/O interconnect system includes a first substrate and a second substrate. The first substrate includes a compliant pillar vertically extending from the first substrate. The compliant pillar is constructed of a first material. The second substrate includes a compliant socket adapted to receive the compliant pillar. The compliant socket is constructed of a second material.Georgia Tech Research Corporatio

Method and apparatus for preparing multiconductor cable with flat conductors

A method and apparatus for preparing flat conductor cable having a plurality of ribbon-like conductors disposed upon and adhesively bonded to the surface of a substrate is described. The conductors are brought into contact with the substrate surface, and while maintained in axial tension on said substrate, the combination is seated on a yieldably compressible layer to permit the conductor to become embedded into the surface of the substrate film