Ultra-high-speed deformation by impact of a projectile flying at speeds on the order of km s

An apparatus was developed to facilitate application of an electro-thermo-chemical accelerator to high-speed deformation experiments. The apparatus is designed on the principle of sequential collision of elastic bodies. Speeds ranging from 600 to 780 m s⁻¹ were achieved, and estimated strain rate of deformation is 10⁷ s⁻¹. The newly developed apparatus can be applied to various types of accelerators for attaining deformation speeds as high as several km s⁻¹. Transmission electron microscopy of aluminum deformed at high speed by use of the apparatus revealed the formation of very small stacking fault tetrahedra (SFTs). This observation is quite new for aluminum; previously, SFTs had not been observed in aluminum, although deformation had been carried out at strain rates lower than 10⁶ s⁻¹. Use of the apparatus promises to provide new insight into high-speed deformation.     

Lantibiotics: insight and foresight for new paradigm

Lantibiotics are a unique type of antimicrobial peptide produced by a large number of gram-positive bacteria that contain unusual amino acids, such as lanthionine and dehydrated amino acids. Ribosomally synthesized lantibiotic prepeptide consists of an N-terminal leader peptide followed by a C-terminal propeptide moiety that undergoes several post-translational modification events to yield a biologically active lantibiotic. Research on lantibiotics has drawn much attention in recent years and has undergone extensive progress as a step forward to the next paradigm. Unusual amino acids in lantibiotics solely contribute to their biological activity and also enhance their structural stability. Thus, enzymes involved in lantibiotic biosynthesis would have a high potential for peptide engineering by introducing unusual amino acids into desired peptides, which may establish a universal approach to advance the structural design of novel peptides, termed lantibiotic engineering. In this review, we focus on recent development with contemporary innovations and perspective of lantibiotic research.     

Query optimization mechanisms in the cloud environments: A systematic study

The goal of a query optimizer is to provide an optimal Query Execution Plan (QEP) by comparing alternative query plans. In a distributed database system over cloud environment, the relations required by a query plan may be stored at multiple sites. This leads to an exponential increase in the number of possible equivalent plan alternatives to find an optimal QEP. Although it is not computationally reasonable to explore exhaustively all possible plans in such large search space. Although query optimization mechanisms are important in the cloud environments, to the best of our knowledge, there exists no complete and systematic review on investigating these issues. Therefore, in this paper, four categories to study these mechanisms are considered which are search‐based, machine learning‐based, schema‐based, and security‐based mechanisms. Also, this paper represents the advantages and disadvantages of the selected query optimization techniques and investigates the metrics of their techniques. Finally, the important challenges of these techniques are reviewed to develop more efficient query optimization techniques in the future.     

Signal-integrity improvement method and its robustness evaluation for VLSI and VLSI-packaging

Nowadays, a GHz frequency signal needs to be propagated on a printed circuit board (PCB) with low distortions. In addition, a higher-frequency signal of 10 GHz or more will also need to be propagated with low distortion in very-large-scale integration (VLSI) in the future. However, signal propagation with low distortion is getting more and more difficult as the frequency increases. In order to solve this problem and to ensure signal integrity, we have proposed a novel transmission line called a “segmental transmission line” (STL). In the STL, a transmission line is divided into multiple segments of individual characteristic impedance. The multiple segments are designed to fix the waveform distortion on the transmission line by solving a combinatorial explosion problem using a genetic algorithm. In a previous article, we have shown the effectiveness of an STL designed for a GHz clock signal in computer simulations. We have also fabricated two scaled-up STL prototypes for a clock signal using real printed circuit boards (PCBs). In this article, we input a random signal by changing its frequency to the scaled-up STL prototype designed for a 150-MHz clock signal. We show that the STL has high robustness to the random signals and the frequency fluctuations, which indicates the generality of the STL technique.     

Biopharmaceutics classification by high throughput solubility assay and PAMPA

The purpose of the present study was to examine the relevancy of the high throughput solubility assay and permeability assay to the biopharmaceutics classification system (BCS). Solubility and permeability were measured by high throughput solubility assay (HTSA) and parallel artificial membrane permeation assay (PAMPA), respectively. High throughput solubility assay was performed using simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid without bile acid (SIF, pH 6.8). We categorize 18 drugs based on the BCS using HTSA and PAMPA. Fourteen out of 18 drugs were correctly classified (78% success rate). The result of the present study showed that HTSA could predict BCS class with a high success rate, and PAMPA could also be useful to predict the permeation of drugs.     

Locating inositol 1,4,5-trisphosphate in the nucleus and neuronal dendrites with genetically encoded fluorescent indicators

Inositol 1,4,5-trisphosphate (InsP3) is a key second messenger in many cell types and also in distinct subcellular regions of single living cells; however, little is examined about the subcellular dynamics of InsP3 in a variety of cell types. We have developed fluorescent indicators to locate InsP3 dynamics in single living cells based on an intramolecular fluorescence resonance energy transfer. Our indicator has visualized InsP3 dynamics in the cytoplasm of cultured cells and even in single thin dendrites of hippocampal neurons, which has been unseen previously. We have further localized the present indicator in the nucleus and pinpointed nuclear InsP3 dynamics. The observation with our nuclear InsP3 indicator has solved a question on nuclear propagation of InsP3 from the cytoplasm and has drawn a conclusion that the nuclear InsP3 dynamics synchronously occurs with cytosolic InsP3 dynamics evoked by agonist stimulations. The present approach contributes to the understanding of when, where, and how InsP3 is generated and removed in a variety of living cells.     

Fiber loop polarizers using a fused taper coupler

All-fiber polarizers using a fused taper coupler are presented. The polarizers are fabricated by constructing a fiber loop joining the output ports of a fused taper coupler. Input light splits into two linearly polarized modes which are reflected and transmitted by the polarizers, respectively. The transmitted and the reflected lights become linearly polarized. The demonstrated polarizer shows an extinction ratio of -20.0 dB     

An evolutionary design methodology of printed circuit boards for high-speed VLSIs

As operation frequencies of the printed circuit boards (PCBs) increase in keeping with VLSI frequencies in the GHz domain, two independent serious problems occur in the PCB design. One is waveform distortion problem, or signal integrity (SI) degradation problem, in PCB traces. And the other is power-supply drop problem, or power integrity (PI) degradation problem, in PCB power planes. Those problems are barely able to be overcome on case-by-case empirical designs conventionally. In this paper we newly propose a design approach for each problem, both of which are based on the genetic algorithm. And we obtained improvement ratios of more than double compared with the both conventional designs for SI and PI degradations, respectively.     

Air‐Stable n‐Type Organic Field‐Effect Transistors Based on Carbonyl‐Bridged Bithiazole Derivatives

An electronegative conjugated compound composed of a newly designed carbonyl‐bridged bithiazole unit and trifluoroacetyl terminal groups is synthesized as a candidate for air‐stable n‐type organic field‐effect transistor (OFET) materials. Cyclic voltammetry measurements reveal that carbonyl‐bridging contributes both to lowering the lowest unoccupied molecular orbital energy level and to stabilizing the anionic species. X‐ray crystallographic analysis of the compound shows a planar molecular geometry and a dense molecular packing, which is advantageous to electron transport. Through these appropriate electrochemical properties and structures for n‐type semiconductor materials, OFET devices based on this compound show electron mobilities as high as 0.06 cm² V^?1 s^?1 with on/off ratios of 10⁶ and threshold voltages of 20 V under vacuum conditions. Furthermore, these devices show the same order of electron mobility under ambient conditions.     

Naphtho[1,2‐c:5,6‐c′]bis[1,2,5]thiadiazole‐Containing π‐Conjugated Compound: Nonfullerene Electron Acceptor for Organic Photovoltaics

The development of nonfullerene acceptor materials applicable to organic photovoltaics (OPVs) has attracted considerable attention for the achievement of a high power conversion efficiency (PCE) in recent years. However, it is still challenging due to the insufficiency of both the variety of effective electron‐deficient units and certain guidelines for the design of such materials. This work focusses on naphtho[1,2‐c:5,6‐c′]bis[1,2,5]thiadiazole (NTz) as a key electron‐deficient unit. Therefore, a new electron‐accepting π‐conjugated compound (NTz‐Np), whose structure is based on the combination of NTz and the fluorene‐containing imide‐annelated terminal units (Np), is designed and synthesized. The NTz‐Np compound exhibits a narrow optical energy gap (1.73 eV), a proper energy level (?3.60 eV) of the lowest unoccupied molecular orbital, and moderate electron mobility (1.6 × 10^?5 cm² V^?1 s^?1), indicating that NTz‐Np has appropriate characteristics as an acceptor against poly(3‐hexylthiophene) (P3HT), a representative donor. OPV devices based on NTz‐Np under the blend with P3HT show high photovoltaic performance with a PCE of 2.81%, which is the highest class among the P3HT/nonfullerene‐based OPVs with the conventional device structure. This result indicates that NTz unit can be categorized as a potential electron‐deficient unit for the nonfullerene acceptors.