Au/GaAs interface annealing study by positron-lifetime spectroscopy

Structural changes of annealed Au contacts on semi-insulating GaAs have been observed by conventional positron lifetime-spectroscopy in which a significant fraction of positrons are drifted from a Na22 source to the contact by an electric field. For annealing temperatures below 200 °C it is found that the interface traps positrons into microvoids with a characteristic positron lifetime of 380±10 ps. For annealing in the range of 300-400 °C a 150±20 ps additional component appears in the lifetime spectra that is attributed to positrons annihilating from AuGa phases at the interface. The most likely explanation for this sudden onset of the positron component in the AuGa phases is that the changes in the GaAs near surface electron chemical potential, brought about by annealing, affect the interfacial dipole in such a way as to allow a favorable potential barrier for positron penetration into the metallic phase. © 1995 The American Physical Society.published_or_final_versio

Transport and Loss of Ring Current Electrons Inside Geosynchronous Orbit During the 17 March 2013 Storm.

Ring current electrons (1-100 keV) have received significant attention in recent decades, but many questions regarding their major transport and loss mechanisms remain open. In this study, we use the four-dimensional Versatile Electron Radiation Belt code to model the enhancement of phase space density that occurred during the 17 March 2013 storm. Our model includes global convection, radial diffusion, and scattering into the Earth's atmosphere driven by whistler-mode hiss and chorus waves. We study the sensitivity of the model to the boundary conditions, global electric field, the electric field associated with subauroral polarization streams, electron loss rates, and radial diffusion coefficients. The results of the code are almost insensitive to the model parameters above 4.5 R E R E, which indicates that the general dynamics of the electrons between 4.5 R E and the geostationary orbit can be explained by global convection. We found that the major discrepancies between the model and data can stem from the inaccurate electric field model and uncertainties in lifetimes. We show that additional mechanisms that are responsible for radial transport are required to explain the dynamics of ≥40-keV electrons, and the inclusion of the radial diffusion rates that are typically assumed in radiation belt studies leads to a better agreement with the data. The overall effect of subauroral polarization streams on the electron phase space density profiles seems to be smaller than the uncertainties in other input parameters. This study is an initial step toward understanding the dynamics of these particles inside the geostationary orbit

Sub-6GHz 4G/5G Conformal Glasses Antennas

© 2013 IEEE. The difficulty of antenna design applied to glasses is that the structure of glasses is too single, and the space available for antenna design is greatly limited. In this background, the integrated design of 4G antennas and 5G antennas applied to glasses is proposed in this paper. The most important highlight of this design is that it makes full use of the limited three-dimensional space structure provided by glasses and achieves the perfect combination of the antenna and glasses in the physical structure. Specifically, two antennas for 4G communication are arranged on two glasses frames, and four antennas for 5G communication are arranged on two glasses legs. In this way, we can make full use of the space provided by the glasses to design antennas and ensure that there is a certain distance between the 4G antennas and 5G antennas so that the performance of both 4G antennas and 5G antennas can be guaranteed. The 4G antenna consists of a loop structure printed on the frame and leg of the glasses and a parasitic branch strip printed on the front of the leg of the glasses. The resonance modes of the 4G antenna are mainly loop, monopole, and dipole modes, which can cover two 4G bands of 0.824-0.96 GHz and 1.71-2.69 GHz. Each 5G antenna mainly comes from the open slot mode etched on the metal ground surface of an FR4 substrate of the glasses leg. In addition, the slot antennas operate in two 5G bands of 3.3-3.6 GHz and 4.8-5.0 GHz. Finally, the glasses and the antennas are fabricated based on FR4 substrates and measured. The measured results show that the proposed antennas perform well and have the potential to be used in 4G/5G communications through glasses

Molecular characterization of HbEREBP2, a jasmonateresponsive transcription factor from Hevea brasiliensis Muell. Arg.

Transcription factors of AP2/ERF superfamily are generally involved in defense responses of plants to biotic and abiotic stresses. Although, defense proteins are present in abundance in laticifers of rubber tree, little is known about their transcriptional regulation. In this study, a full length cDNA, referred to as HbEREBP2 was characterized by means of bioinformatic analysis and quantitative real-time RT-PCR. The HbEREBP2 was 786-bp in length and contained a 480-bp open reading frame (ORF) encoding a protein of 159 amino acid residues. Bioinformatic analysis showed that the deduced amino acid sequence of HbEREBP2 had a specific domain of AP2 superfamily and shared relative high identity with members of CBF/DREB subfamily from different plant species. Quantitative real-time RT-PCR revealed that methyl jasmonate was more effective than ethylene and rapidly than mechanical wounding on upregulating HbEREBP2 expression. The results suggest that HbEREBP2 may be involved in the regulation of jasmonate-mediated defense responses in laticifers of rubber tree.Key words: Hevea brasiliensis, Laticifer, defense proteins, AP2/ERF transcription factor, Methyl jasmonates, Ethephon, mechanical wounding

Effect of sunlight shielding on leaf structure and amino acids concentration of light sensitive albino tea plant

Light sensitive albino tea cultivar ‘Jinguang’ (Camellia sinensis) which grows albinism leaf in yellow colour, results to high level of amino acids but low levels of photosynthetic pigments including chlorophylls, neoxanthin, violaxanthin, phytoxanthin and β-carotene when it is exposed to high sunlight illumination in the summer season. In this case, the chloroplasts showed partially lysed, with few thylakoids. The leaf albinism was reverted when the leaf was shielded from direct illumination of strong sunlight. It is considered that the blocked development of chloroplast and photosynthetic pigments in the albinism leaf inhibited the biosynthesis of leaf proteins, resulting in an accumulation of free amino acids.Keywords: Camellia sinensis, leaf albinism, light intensity, photosynthetic pigments, amino acids, chloroplastAfrican Journal of Biotechnology Vol. 12(36), pp. 5535-553

Biomimetic synthesis of struvite with biogenic morphology and implication for pathological biomineralization

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Selective interaction of Hpn-like protein with nickel, zinc and bismuth in vitro and in cells by FRET

Hpn-like (Hpnl) is a unique histidine- and glutamine-rich protein found only in Helicobacter pylori and plays a role on nickel homeostasis.Weconstructed the fluorescent sensor proteins CYHpnl and CYHpnl_1-48 (C-terminal glutamine-rich region truncated) using enhanced cyan and yellow fluorescent proteins (eCFP and eYFP) as the donor–acceptor pair to monitor the interactions of Hpnl with metal ions and to elucidate the role of conserved Glu-rich sequence in Hpnl by fluorescence resonance energy transfer (FRET). CYHpnl and CYHpnl_1-48 exhibited largest responses towards Ni(II) and Zn(II) over other metals studied and the binding of Bi(III) to CYHpnl was observed in the presence of an excess amount of Bi(III) ions (Kd =115±4.8 μM). Moreover, both CYHpnl and CYHpnl_1-48 showed positive FRET responses towards the binding to Ni(II) and Zn(II) in Escherichia coli cells overexpressing CYHpnl and CYHpnl_1-48, whereas a decrease in FRET upon Bi(III)-binding in E. coli cells overexpressing the latter. Our study provides clear evidence on Hpnl binding to nickel in cells, and intracellular interaction of Hpnl with Bi(III) could disrupt the protein function, thus probably contributing to the efficacy of Bi(III) drugs against H. pylori.postprin

Ab Initio Investigation of Charge Trapping Across the Crystalline- Si -Amorphous- Si O2 Interface

Accurate microscopic description of the charge-trapping process from semiconductor to defects in the dielectric-oxide layer is of paramount importance for understanding many microelectronic devices such as complementary metal-oxide-semiconductor (CMOS) transistors, as well as electrochemical reactions. Unfortunately, most current microscopic descriptions of such processes are based on empirical models with parameters fitted to experimental device performance results or simplified approximations like the Wentzel-Kramers-Brillouin (WKB) method. Some critical questions are still unanswered, including: What controls the charge-hopping rate, the coupling strength between the defect level to semiconductor level, or the energy difference? How does the hopping rate decay with defect-semiconductor distance? What is the fluctuation of the defect level, especially in amorphous dielectrics? Many of these questions can be answered by ab initio calculations. However, to date, there are few ab initio studies for this problem mainly due to technical challenges from atomic-structure construction to large-system calculations. Here, using the latest advances in calculation methods and codes, we study the carrier-trapping problem using density-functional theory (DFT) based on the Heyd-Scuseria-Ernzerhof (HSE) exchange correlation functional. The valence bond random-switching method is used to construct the crystalline-Si-amorphous-SiO2 (c-Si/a-SiO2) interfacial atomic structure, and the HSE yields a band offset that agrees well with experiments. The hopping rate is calculated with the Marcus theory, and the hopping-rate dependences on the gate potential and defect distances are revealed, as well as the range of fluctuation results from amorphous structural variation. We also analyze the result with the simple WKB model and find a major difference in the description of the coupling constant decay with the defect-semiconductor distance. Our results provide the ab initio simulation insights for this important carrier-trapping process for device operation

Intubation without muscle relaxation for suspension laryngoscopy: A randomized, controlled study

Objective and Aim: The objective of the following study is to examine the effectiveness and safety of suspension laryngoscopy under intubation with propofol and remifentanil alone for vocal fold nodule (VFN) excision.Materials and Methods: A total of 40 patients were equally and randomly assigned to elective VFN excision using suspension laryngoscopy under intubation with propofol and remifentanil alone (Group A) or with  supplementary cisatracurium (Group B).Results: Intubation time was significantly longer in Group A than in Group B (300.0 } 30.0 s vs. 265.2 } 38.7 s, P = 0.003). The two groups showed similar Cormack.Lehane classifications, intubation conditions and ease ofsuspension laryngoscopy. Both groups showed favorable cardiopulmonary safety profiles. Post.anesthesia recovery was significantly more rapid in Group A than in Group B, in terms of times to spontaneous breathing return (7.2 } 1.4 min vs. 10.9 } 1.6 min, P < 0.001), consciousness return (7.4 } 1.5 min vs. 12.3 } 1.8 min, P < 0.001), removal of tracheal intubation (8.1 } 1.5 min vs. 13.2 } 1.7 min, P < 0.001) and operating room discharge (12.7 } 1.4 min vs. 22.1 } 1.3 min, P < 0.001).Conclusion: Use of propofol and remifentanil alone provides favorable intubation and anesthesia conditions for suspension laryngoscopic VFN excision and accelerates post.anesthesia recovery.Key words: Endotracheal intubation, muscle relaxant, propofol,  randomized controlled study, remifentanil, suspension laryngoscopy, vocal fold nodul