Miniature transparent UWB antenna with tunable notch for green wireless applications

Copyright @ 2011 IEEEA miniature transparent UWB antenna with tunable notch that can be incorporated with a solar panel for harnessing solar energy has been proposed and presented. The antenna demonstrates a good omni-directional radiation pattern throughout the FCC bandwidth of 3.1 – 10.6 GHz and a comparable gain making it a good candidate for future green wireless applications

Simultaneous stabilization via static output feedback and state feedback

In this paper, the simultaneous stabilization problem is considered using the matrix inequality approach. Some necessary and sufficient conditions for simultaneous stabilizability of r strictly proper multi-input/multi-output (MIMO) plants via static output feedback and state feedback are obtained in the form of coupled ARI's. It is shown that any such stabilizing feedback gain is the solution of some coupled linear quadratic control problems where every cost functional has a suitable cross term. A heuristic iterative algorithm based on the linear matrix inequality (LMI) technique is presented to solve the coupled matrix inequalities. The effectiveness of the approach is illustrated by numerical example.published_or_final_versio

Rock-salt SnS and SnSe: Native Topological Crystalline Insulators

Unlike time-reversal topological insulators, surface metallic states with Dirac cone dispersion in the recently discovered topological crystalline insulators (TCIs) are protected by crystal symmetry. To date, TCI behaviors have been observed in SnTe and the related alloys Pb$_{1-x}$Sn$_{x}$Se/Te, which incorporate heavy elements with large spin-orbit coupling (SOC). Here, by combining first-principles and {\it ab initio} tight-binding calculations, we report the formation of a TCI in the relatively lighter rock-salt SnS and SnSe. This TCI is characterized by an even number of Dirac cones at the high-symmetry (001), (110) and (111) surfaces, which are protected by the reflection symmetry with respect to the ($\bar{1}$10) mirror plane. We find that both SnS and SnSe have an intrinsically inverted band structure and the SOC is necessary only to open the bulk band gap. The bulk band gap evolution upon volume expansion reveals a topological transition from an ambient pressure TCI to a topologically trivial insulator. Our results indicate that the SOC alone is not sufficient to drive the topological transition.Comment: 5 pages, 5 figure

Selective binding of Hpnl towards Ni(II) and Bi(III)

Poster-5Histidine-rich protein Hpn and histidine- and glutamine-rich protein Hpn-like (Hpnl) in Helicobacter pylori have been corroborated to be crucial to nickel homeostasis.[1-3] Nickel supply to hydrogenases and ureases might be disrupted owing to the interaction of metallodrugs, such as bismuth antiulcer drugs, with Hpnl, which may subsequently disturb the functions of the essential …postprin

An Intergrated Approach for Matching Metals and Metallodrugs to Proteins

Keynote Lecture (Abstract)The effect of metals in biology effects is double-edged. Metal ions operate, on one hand, as cofactors for around 40% enzymes, on the other hand, they also exhibit toxic effects. Some metal ions, although being not essential, have been widely used in human healthcare as either therapeutic agents or diagnosis agents. To understand the molecular mechanism of a metallodrug, it is crucial to match metals to proteins at a proteome-wide scale [1,2]. We used an integrated approach consisting of gel electrophoresis and inductively coupled plasma mass spectrometry, LA-ICP-MS, IMAC and bioinformatic approach to identify metal-associated proteins using bismuth antiulcer drug as an example [3,4]. Using continuous-flow gel electrophoresis in combination with ICP-MS, we developed a comprehensive and robust strategy to readily identify metal-associated proteins as well as to quantify the metals for fast metallome/proteome-wide profiling of metal-binding proteins. At the same time, we have developed a tunable fluorescent method to visualize metalbinding proteins and histidine-rich proteins directly in cells. To match metals to proteins, we also established a bioinformatic method which allows potential metal-binding proteins both sequentially and spaciously to be searched [5-7]. Surprisingly, histidine-rich proteins and motifs(HRMs) are commonly found in proteins. We systematically analyzed the proteomes of 675 prokaryotes including 50 archaea and 625 bacteria for HRMs, and show that HRMs are extensively distributed in prokaryotic proteomes, with the majority (62%) of histidine-rich proteins (HRPs) being involved in metal homeostasis. Importantly, the occurrence of histidine-rich proteins (motifs) in the proteomes of prokaryotes is related to their habitats.published_or_final_versio

Positron-annihilation study of compensation defects in InP

Positron-annihilation lifetime and positron-annihilation Doppler-broadening (PADB) spectroscopies have been employed to investigate the formation of vacancy-type compensation defects in n-type undoped liquid encapsulated Czochrolski grown InP, which undergoes conduction-type conversions under high temperature annealing. N-type InP becomes p-type semiconducting by short time annealing at 700°C, and then turns into n-type again after further annealing but with a much higher resistivity. Long time annealing at 950°C makes the material semi-insulating. Positron lifetime measurements show that the positron average lifetime τ av increases from 245 ps to a higher value of 247 ps for the first n-type to p-type conversion and decreases to 240 ps for the ensuing p-type to n-type conversion. The value of τ av increases slightly to 242 ps upon further annealing and attains a value of 250 ps under 90 h annealing at 950°C. These results together with those of PADB measurements are explained by the model proposed in our previous study. The correlation between the characteristics of positron annihilation and the conversions of conduction type indicates that the formation of vacancy-type defects and the progressive variation of their concentrations during annealing are related to the electrical properties of the bulk InP material. © 2002 American Institute of Physics.published_or_final_versio

Positron-lifetime study of compensation defects in undoped semi-insulating InP

Positron-lifetime and infrared-absorption spectroscopies have been used to investigate the compensation defects that render undoped n-type liquid encapsulated Czochralski-grown InP semi-insulating under high-temperature annealing. The positron measurements, carried out over the temperature range of 25-300 K, reveal in the as-grown material a positron lifetime of 282±5 ps which we associate with either the isolated indium vacancy V 3- In or related hydrogen complexes. The shallow donor complex V InH 4, responsible for much of the n-type conductivity and the strong infrared absorption signal at 4320 nm, is ruled out as a significant trapping site on the grounds that its neutral state is present at too low a concentration. After annealing at 950°C, in conjunction with the disappearance of the V InH 4 infrared-absorption signal, trapping into V In-related centers is observed to increase slightly, and an additional positron trapping defect having a lifetime of 330 ps appears at a concentration of ∼10 16 cm -3, indicating divacancy trapping. These results support the recent suggestion that the V InH 4 complex present in as-grown InP dissociates during annealing, forming V InH (3-n)- n (0≤n≤3) complexes and that the recombination of V In with a phosphorus atom results in the formation of EL2-like deep donor P In antisite defect, which compensates the material. It is suggested that the divacancy formed on annealing is V InV P, and that this defect is probably a by-product of the P In antisite formation.published_or_final_versio

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

Offset-fed UWB antenna with multi-slotted ground plane

This paper presents the design and results of an offset feed Ultrawideband(UWB) antenna with a multiple-slotted ground plane. The antenna consists of a square shaped radiator, a feed slightly offset from the middle along the radiator side and a ground plane with multiple rectangular slots. Simulation results show that the antenna can achieve a wide bandwidth from 3.3 to 18 GHz. © 2011 IEEE.published_or_final_versionThe 2011 International Workshop on Antenna Technology (iWAT), Hong Kong, China, 7-9 March 2011. In Proceedings of iWAT, 2011, p. 432-43

Meteorin regulates mesendoderm development by enhancing nodal expression

During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development. It is highly expressed in the inner cell mass of blastocysts and further in the epiblast and extra-embryonic ectoderm during gastrulation. Genetic ablation of the Meteorin gene resulted in early embryonic lethality, presumably due to impaired lineage allocation and subsequent cell accumulation. Embryoid body culture using Meteorin-null embryonic stem (ES) cells showed reduced Nodal expression and concomitant impairment of mesendoderm specification. Meteorin-null embryos displayed reduced levels of Nodal transcripts before the gastrulation stage, and impaired expression of Goosecoid, a definitive endoderm marker, during gastrulation, while the proximo-distal and anterior-posterior axes and primitive streak formation were preserved. Our results show that Meteorin is a novel regulator of Nodal transcription and is required to maintain sufficient Nodal levels for endoderm formation, thereby providing new insights in the regulation of mesendoderm allocation.open1113sciescopu