Al 2 O 3 was deposited on In 0.15 Ga 0.85 As/ GaAs using atomic-layer deposition ͑ALD͒. Without any surface preparation or postthermal treatment, excellent electrical properties of Al 2 O 3 / InGaAs/ GaAs heterostructures were obtained, in terms of low electrical leakage current density ͑10 −8 to 10 −9 A/cm 2 ͒ and low interfacial density of states ͑D it ͒ in the range of 10 12 cm −2 eV −1. The interfacial reaction and structural properties studied by high-resolution x-ray photoelectron spectroscopy ͑HRXPS͒ and high-resolution transmission electron microscopy ͑HRTEM͒. The depth profile of HRXPS, using synchrotron radiation beam and low-energy Ar + sputtering, exhibited no residual arsenic oxides at interface. The removal of the arsenic oxides from Al 2 O 3 / InGaAs heterostructures during the ALD process ensures the Fermi-level unpinning, which was observed in the capacitance-voltage measurements. The HRTEM shows sharp transition from amorphous oxide to single crystalline semiconductor.

Immunoaffinity columns are prepared from the monoclonal antibody (MAb) GAD-1. These columns are used to enrich glutamic acid decarboxylase (GAD) from the cytosolic fraction of rat brain homogenates and from Triton X-100 extracts of the brain membrane fraction. In each case enzyme activity is enriched over 400-fold. The immunopurified fractions were analyzed by SDS-PAGE. Fractions purified from the cytosol consisted of a quantitatively major band of 59 kDa, and one band of 63 kDa, as well as a group centered around 55 kDa. Fractions purified from membranes consisted primarily of the 59 and 63 kDa components; only traces of the lower-molecular-weight components were present. The entire set of proteins purified on GAD-1 immunoaffinity columns is strongly recognized by 2 widely used antisera to GAD, those described in Saito et al. (1974) and Oertel et al. (1981). The 59 kDa protein from the cytosolic fraction was purified to homogeneity by preparative SDS-PAGE; a partial amino acid sequence of this protein was obtained. The 59 kDa protein has a high degree of sequence homology with the deduced amino acid sequence of the protein that was coded for by a cDNA for feline GAD (Kaufman et al., 1986; Kobayashi et al., 1987). Thus, these proteins are either products of a single gene that diverged during the evolution of rat and cat from a common ancestor, or are members of a closely related set of genes found in both species. The MAb GAD-6 recognizes the 59 kDa band and the group of bands centered around 55 kDa on Western blots. Therefore, these proteins are immunochemically related. GAD-6 does not recognize the 63 kDa band. In Western blots of unfractionated homogenates of the whole brain, the only band recognized by GAD-6 is a 59 kDa band.(ABSTRACT TRUNCATED AT 250 WORDS)

Both bevacizumab and ranibizumab showed similar efficacy in the regression of ROP with minor mean refractive errors at 1 year of corrected age. However, high myopia was more prevalent in the bevacizumab-treated eyes.

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In the present study, we demonstrate the thermal induced amyloid formation in a ␤-barrel protein, such as the acidic fibroblast growth factor from Notopthalmus viridescens (nFGF-1). Fibril formation in nFGF-1 is observed to occur maximally at 65°C. Electron microscope analysis of the thermal induced fibrils of nFGF-1 shows that they are filamentous with an average diameter of about 20 nm. X-ray diffraction analysis reveals that the thermal induced fibrils of nFGF-1 have a typical "cross-␤" structure with the ␤-strands perpendicular to the fibril axis. By using a variety of biophysical techniques including multidimensional NMR, we demonstrate that fibril formation involves the formation of a partially structured intermediate(s) in the thermal unfolding pathway of the protein (nFGF-1). Results of the anilino-8-napthalene sulfonate binding experiments indicate that fibril formation occurs due to the coalescence of the protein (in the intermediate state(s))through the solvent-exposed non-polar surface(s). In this study, we also demonstrate that organic osmolytes, such as proline, can efficiently prevent the thermal induced amyloid formation in nFGF-1. Proline is found to stabilize the native conformation of the protein. The addition, proline is observed to increase the cooperativity of the unfolding (native 7 denatured) reaction and consequently decrease the population of the "sticky" thermal equilibrium intermediate(s) responsible for the fibril formation.

Five monoclonal antibodies that recognize chicken brain glutamic acid decarboxylase (GAD) have been selected and designated GAD-1 to -5. GAD-1 to -5 were selected on the basis of their ability to immunoprecipitate active GAD from crude brain extracts. GAD-1 recognizes an epitope that is conserved in many vertebrates; the epitope recognized by GAD-5 is restricted to the chicken. Radioimmunoassays with GAD-1 indicate that GAD is highly enriched in brain relative to other tissues. GAD was localized immunocytochemically with GAD-1 and GAD-2 in rat cerebellum, spinal cord, and retina. The staining pattern is in agreement with that obtained previously with polyclonal antisera to GAD. GAD from the chicken brain was purified by chromatography on an immunoaffinity column made of GAD-1. NaDodSO4/PAGE analysis of the immunoafflity-purified GAD fractions shows a major band of 59 kDa and minor bands at 63 and 54 kDa.The enzyme glutamic acid decarboxylase (GAD) catalyzes the conversion of glutamic acid to y-aminobutyric acid (GABA) and CO2. The tissue and cellular distribution of GAD is highly restricted. GAD is localized largely to neurons and in particular to those that appear to use GABA as a neurotransmitter. Thus, the expression of GAD plays a key role in determining a neuron's transmitter phenotype.Many of the important kinetic and chemical properties of mammalian GAD were elucidated in the fundamental and pioneering studies of Roberts and his colleagues (reviewed in ref. 1). Subsequent work has raised the possibility that important kinetic variant forms of GAD exist (2-4). Purification of GAD by conventional biochemical methods is beset with a number ofproblems, including a relatively low starting concentration in the brain, a tendency of the enzyme to aggregate, and the necessity of multiple column separations to resolve GAD from other proteins. As a consequence, certain basic questions remain unanswered. Wu et al. (5) have purified mouse brain GAD to apparent homogeneity. However, NaDodSO4/PAGE analysis of the pure preparation reveals multiple bands ranging from 15 to 118 kDa (6). The relationship of these multiple bands to the active form(s) of the enzyme has not been elucidated. Antisera to this preparation have been extensively used to map the distribution of GAD in the brain (1). The exact range of polypeptides recognized by such antisera remains to be defined. No data on the amino acid sequence of GAD have been published.Monoclonal antibodies (mAbs) to GAD could greatly facilitate research on many aspects of the enzyme and the neurons that contain it. In this report, we describe five mAbs (GAD-1 to -5) that recognize GAD. GAD-1 and -2 are useful for immunohistochemical localization of the enzyme. Immunoaffinity purification with GAD-1 has given new data on the molecular nature of GAD. MATERIALS AND METHODSPartial Purification of GAD from Chicken Brains. GAD was partially purified from chicken brains by methods adapted from those of Wu et al. (5) and Oertel et al. (7). Frozen adult chicken brains were obt...

High HfO 2 was deposited on n-type GaN ͑0001͒ using atomic layer deposition with Hf͑NCH 3 C 2 H 5 ͒ 4 and H 2 O as the precursors. Excellent electrical properties of TiN / HfO 2 / GaN metal-oxide-semiconductor diode with the oxide thickness of 8.8 nm were obtained, in terms of low electrical leakage current density ͑ϳ10 −6 A/cm 2 at V FB +1 V͒, well behaved capacitance-voltage ͑C-V͒ curves having a low interfacial density of states of 2 ϫ 10 11 cm −2 eV −1 at the midgap, and a high dielectric constant of 16.5. C-V curves with clear accumulation and depletion behaviors were shown, along with negligible frequency dispersion and hysteresis with sweeping biasing voltages. The structural properties studied by high-resolution transmission electron microscopy and x-ray reflectivity show an atomically smooth oxide/GaN interface, with an interfacial layer of GaON ϳ1.8 nm thick, as probed using x-ray photoelectron spectroscopy.

To effectively passivate the technologically important GaAs ͑001͒ surfaces, in situ deposition of Al 2 O 3 was carried out with molecular beam epitaxy. The impacts of initial GaAs surface reconstruction and post-deposition annealing have been systematically investigated. The corresponding interfacial state density ͑D it ͒ were derived by applying the conductance method at 25 and 150°C on both p-type and n-type GaAs metal-oxide-semiconductor capacitors to establish the D it spectra in proximity of the critical midgap region. We show that significant reduction of D it near the midgap is achieved by applying an optimized thermal annealing on samples grown on a Ga-rich ͑4 ϫ 6͒ reconstructed surface.