Uniform Insertion Research Articles

Analytical Analysis of Power-Constrained Repeaters’ Insertion in Large-Scale CMOS Chips

As the die area of CMOS integrated circuits continues to increase, interconnects will become dominant in determining the performance of the circuits from the standpoint of speed and power consumption. Uniform repeater insertion is an effective method used to reduce the propagation delay of a signal in long resistive-capacitive lines. However, non-optimal repeaters’ insertion yields non-optimal circuit performance. In this work, we provide a mathematical treatment for optimal repeater insertion with power consumption constraints. In particular, a closed-form expression for the optimum number and size of repeaters is given for a two-stage buffer used as a repeater. The validation of the analytical solution is assessed by means of circuit simulations, by comparing the theoretical optimal number and size of the repeaters to be placed in the long resistive-capacitive line with the simulated values.

Reducing contact resistance of MoS2-based field effect transistors through uniform interlayer insertion via atomic layer deposition.

Molybdenum disulfide (MoS2), a semiconducting two-dimensional layered transition metal dichalcogenide (2D TMDC), with attractive properties enables the opening of a new electronics era beyond Si. However, the notoriously high contact resistance (RC) regardless of the electrode metal has been a major challenge in the practical applications of MoS2-based electronics. Moreover, it is difficult to lower RC because the conventional doping technique is unsuitable for MoS2 due to its ultrathin nature. Therefore, the metal-insulator-semiconductor (MIS) architecture has been proposed as a method to fabricate a reliable and stable contact with low RC. Herein, we introduce a strategy to fabricate MIS contact based on atomic layer deposition (ALD) to dramatically reduce the RC of single-layer MoS2 field effect transistors (FETs). We utilize ALD Al2O3 as an interlayer for the MIS contact of bottom-gated MoS2 FETs. Based on the Langmuir isotherm, the uniformity of ALD Al2O3 films on MoS2 can be increased by modulating the precursor injection pressures even at low temperatures of 150 °C. We discovered, for the first time, that film uniformity critically affects RC without altering the film thickness. Additionally, we can add functionality to the uniform interlayer by adopting isopropyl alcohol (IPA) as an oxidant. Tunneling resistance across the MIS contact is lowered by n-type doping of MoS2 induced by IPA as the oxidant in the ALD process. Through a highly uniform interlayer combined with strong doping, the contact resistance is improved by more than two orders of magnitude compared to that of other MoS2 FETs fabricated in this study.

Performance evaluation of a parabolic trough collector with a uniform helical wire coil flow insert

Solar energy is an extremely useful and dependable renewable energy source for meeting our society's diverse energy demands. Solar concentrator-based energy systems are currently the most efficient methods of using solar energy. Among these technologies, the parabolic trough collector is a mature and effective concentrating solar power technology with a wide range of real-world applications using solar alone or in combination with other energy sources. Flow insert is a potential approach for improving parabolic trough solar collector performance through enhanced heat transfer and heat absorption. The purpose of this study is to determine the feasibility of using a uniform helical wire coil flow insert in the LS-2 parabolic trough solar collector module. A computational fluid dynamic model developed in Ansys 18.1 is used in the current investigation. A uniform helical wire coil flow insert is modeled and compared with the plain tube without any insert inside it. Flow analysis, overall efficiency, exergy efficiency, and thermal efficiency are compared in the evaluation process. The overall efficiency and exergy efficiency of the parabolic trough collector are the most critical criteria in determining its performance. The parabolic trough collector is examined using a range of inlet fluid temperatures ranging from 303 K to 603 K and a volumetric flow rate of 50 L per minute to 250 L per minute. The pumping work is found to be the lowest, indicating that the increase in pressure drop has a negligible effect on the overall system performance. For the flow rate of 50 L per minute and inlet heat transfer fluid temperature of 303 K, the overall, exergy and thermal efficiency using a uniform helical wire coil flow insert are found to be 2.07 %, 2.1 %, and 2.2 %, respectively.

A convergence time of Grover walk on regular graph to stationary state with constant inflow to every vertex

We consider a quantum walk model on a finite graph which has an interaction with the outside. Here a quantum walker from the outside penetrates the graph and also a quantum walker in the graph goes out to the outside at every time step. This dynamics of the quantum walk converges to a stationary state. In this paper, we estimate the speed of the convergence to the stationary state on the κ-regular graph with the uniform insertion of the inflow to the graph. We show that larger degree of the regular graph makes the convergence time of this quantum walk model slower under this set-up.

Abstract 215: A novel enzymatic library preparation workflow that dramatically reduces artifacts associated with damaged FFPE samples

Abstract Clinical oncology heavily relies on formalin-fixed, paraffin-embedded (FFPE) tissue samples for histology and molecular characterization. The chemical and physical modifications of nucleic acids introduced during fixation, storage and purification negatively impact molecular profiling and vary from sample-to-sample. Conventional sonication and ligation-based library preparation is considered the gold-standard approach for FFPE samples, but it is time-consuming and expensive. Importantly, these processes introduce artifacts that impact downstream analysis and interpretation (Haile et al., 2019). We have developed a novel fragmentation chemistry that virtually eliminates hairpin artifacts, achieving levels on par with non-FFPE control samples. Our fragmentation method is highly scalable, exhibits minimal sequence bias, and reduces cost and workflow inefficiencies associated with mechanical shearing. In this study, we developed a unified method for library preparation from FFPE samples which produces similar insert sizes across variable input mass and quality of FFPE samples. We carefully evaluated the performance of this method relative to a sonication-based approach employing the KAPA HyperPrep kit. Libraries were constructed from 50 to 200 ng of FFPE DNA, inputs typically used for NGS, ranging from low-to high-quality as assessed using a qPCR-based method and DNA integrity (DIN). Targeted sequencing was performed using a 37 kb custom oncology hybridization capture panel to investigate molecular complexity. Our workflow virtually eliminated hairpin artifacts that were present in up to 4.5% of reads in sonication-based libraries. Soft-clipping was also 3- to 7-fold lower in libraries prepared with the Watchmaker kit relative to sonicated DNA libraries, improving overall sequencing economy. Furthermore, the mean target coverage achieved with the Watchmaker kit was comparable to or higher than sonication libraries using the same input mass. Because input masses were normalized post-shearing, which typically results in 20-40% sample loss, coverage with our approach is significantly higher relative to sonication, if normalizing to pre-sheared DNA input. Watchmaker DNA Library Preparation with Fragmentation enables high-quality DNA library preparation from damaged FFPE samples, producing high target coverage, uniform insert size, and minimizing sequencing artifacts to improve sensitivity and specificity. This approach is highly scalable and automatable, enabling various oncology applications. Citation Format: Giulia Corbet, Philip Benson, Kailee Reed, Skyler Mishkin, Thomas Harrison, Kristin Scott, Zane Jaafar, Kristina Giorda, Josh Haimes, Martin Ranik, Brian Kudlow. A novel enzymatic library preparation workflow that dramatically reduces artifacts associated with damaged FFPE samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 215.

다기능 투과배열 안테나 단위셀 소형화 설계를 위한 360° 반사형 축소형 아날로그 위상 천이기 설계

This study compares the designs of one-stage and two-stage reflection-type phase shifters for miniaturized S-band multi-functional transmit-array antennas. Both phase shifters have areas smaller than 0.2 λ0×0.4 λ0, which is less than half of the conventional unit cell size of 0.5λ λ0×0.5 λ0, and both phase shifters have a phase shifting range of more than 360°. The one-stage phase shifter requires a miniaturized hybrid coupler, 1/4 wavelength transmission line, and additional elements to implement a wide phase shifting range; hence, the phase shifter has a non-uniform insertion loss distribution and a peak insertion loss of 4.3 dB. The two-stage phase shifter outperformed the one-stage phase shifter; it had a relatively uniform insertion loss distribution of 2.5 dB because of its simple circuit structure.

Anomalous displacement reaction for synthesizing above-room-temperature and air-stable vdW ferromagnet PtTe2Ge1/3.

Emerging van der Waals (vdW) magnets provide a paradise for the exploration of magnetism in the ultimate two-dimensional (2D) limit, and the construction of integrated spintronic devices, and have become a research frontier in the field of low-dimensional materials. To date, prototypical vdW magnets based on metals of the first transition series (e.g. V, Cr, Mn and Fe) and chalcogen elements suffer from rapid oxidation restricted by the Hard-Soft-Acid-Base principle, as well as low Curie temperatures (T C), which has become a generally admitted challenge in 2D spintronics. Here, starting from air-unstable Cr2Ge2Te6 vdW thin flakes, we synthesize Ge-embedded PtTe2 (namely PtTe2Ge1/3) with superior air stability, through the displacement reaction in the Cr2Ge2Te6/Pt bilayer. In this process, the anomalous substitution of Cr with Pt in the thermal diffusion is inverse to the metal activity order, which can be attributed to the compatibility between soft-acid (Pt) and soft-base (Te) elements. Meanwhile, the layered uniform insertion of Ge unbalances Pt-Te bonds and introduces long-range ordered ferromagnetism with perpendicular magnetic anisotropy and a Curie temperature above room temperature. Our work demonstrates the anti-metal-activity-order reaction tendency unique in 2D transition-metal magnets and boosts progress towards practical 2D spintronics.

LI-Detector: a Method for Curating Ordered Gene-Replacement Libraries.

ABSTRACTIn recent years the availability of genome sequence information has grown logarithmically resulting in the identification of a plethora of uncharacterized genes. To address this gap in functional annotation, many high-throughput screens have been devised to uncover novel gene functions. Gene-replacement libraries are one such tool that can be screened in a high-throughput way to link genotype and phenotype and are key community resources. However, for a phenotype to be attributed to a specific gene, there needs to be confidence in the genotype. Construction of large libraries can be laborious and occasionally errors will arise. Here, we present a rapid and accurate method for the validation of any ordered library where a gene has been replaced or disrupted by a uniform linear insertion (LI). We applied our method (LI-detector) to the well-known Keio library of Escherichia coli gene-deletion mutants. Our method identified 3,718 constructed mutants out of a total of 3,728 confirmed isolates, with a success rate of 99.7% for identifying the correct kanamycin cassette position. This data set provides a benchmark for the purity of the Keio mutants and a screening method for mapping the position of any linear insertion, such as an antibiotic resistance cassette in any ordered library.IMPORTANCE The construction of ordered gene replacement libraries requires significant investment of time and resources to create a valuable community resource. During construction, technical errors may result in a limited number of incorrect mutants being made. Such mutants may confound the output of subsequent experiments. Here, using the remarkable E. coli Keio knockout library, we describe a method to rapidly validate the construction of every mutant.

Olefin polymerization cocatalysts: Development, applications, and prospects

<p indent="0mm">The annual global production of polyolefin products exceeds 100 million tons, and they are widely used in various fields. In contrast to heterogeneous polymerization that produces polyolefins with broad dispersity, single-site transition-metal-catalyzed homogeneous olefin polymerization enables the synthesis of polyolefins with narrow molecular weight distribution, controllable chain segment length, and uniform insertion ratio. It can flexibly tune the molecular structure of polyolefins to provide polyolefin materials with the required properties, which can be applied to high-end applications such as medical packaging and medical equipment. It is important to choose a suitable combination of a catalyst and cocatalyst to obtain tailor-made polyolefins through high-efficiency homogeneous polymerization. The main function of the cocatalyst is to react with the catalyst precursor to generate and stabilize active metal cations, the latter being the center of catalyzing olefin polymerizations. This review summarizes the most important work regarding cocatalysts in the past two decades, including novel structures: Mono/dinuclear boron-, aluminum-, and polymer-based promoters. This review illustrates the importance of the weakly coordinative nature of the counter anion, providing the design principle for the development of a highly efficient cocatalyst. Activation mechanism: The use of an industrial catalysis-related pyridylamido hafnium complex is an example that showcases the complicated reactions of this catalyst with different cocatalysts, shedding light on the importance of choosing the pair of catalyst and cocatalyst. Applications in polymerization: Binuclear cocatalysts and the cocatalysts combined with coordination chain transfer polymerizations are used to synthesize novel structural polyolefins, indicating that the cocatalyst plays a crucial role in alternating polyolefin structures. Cocatalyst-involved catalyst deactivation reactions: This part emphasizes the reaction pathways of cocatalysts that lead to catalyst deactivation, including the replacement of metal and ligand. Further, this review proposes the possible future development of cocatalysts by investigating the reported compounds with high Lewis acidity and the development of novel functionalized cocatalysts. For instance, the development of external stimuli-responsive cocatalyst structures may be one of the future development directions. Combining cocatalysts with existing catalytic methods, such as the coordinative chain transfer polymerization for synthesizing polyolefins with a novel structure, may be the second development direction in the future. With the advancement of computer hardware and algorithms together with experimental data, computational chemistry helps understand the effect of cocatalysts on polymerization. Predicting the structure of new and efficient cocatalysts through big data and artificial intelligence is the third possible future development direction.

3D integrated wavelength demultiplexer based on a square-core fiber and dual-layer arrayed waveguide gratings.

We present a 3D integrated wavelength demultiplexer using a square-core fiber (SCF) and matched dual-layer arrayed waveguide gratings (AWGs). The SCF works as a 3D fiber multimode interference device, which splits the input light into symmetric four spots. The spots are then coupled to a pitch-matched 4-waveguide network, each connecting an AWG. Interface waveguides are designed to improve the coupling efficiency between the SCF and the dual-layer chip. The four AWGs are designed with different central wavelengths and a large free spectral range (FSR) of 120 nm. To reach a small and uniform insertion loss among different channels, only the central channels of each AWG are used for demultiplexing. The device is fabricated on a polymer platform. The upper and lower layers of the chip are fabricated using the same photolithography mask but rotated 180° so that 4 different AWG designs can be mapped to a single chip. The measured transmission spectra of the four AWGs cover a bandwidth of 112 nm. The insertion loss variation is smaller than 1.4 dB. The designed device can find applications in fiber optic sensing, communication, and astronomy.

Ultrahigh “Relative Energy Density” and Mass Loading of Carbon Cloth Anodes for K-Ion Batteries

Mass loading and potential plateau are the two most important issues of potassium (K)-ion batteries (KIBs), but they have long been ignored in previous studies. Herein, we report a simple and scala...

Degradable Poly(alkyl acrylates) with Uniform Insertion of Ester Bonds, Comparing Batch and Semibatch Copolymerizations

Poly(alkyl)acrylates are a major class of nonbiodegradable polymers which are difficult to recycle due to an all-carbon backbone. Introducing a certain number of ester bonds in the backbone via rad...

Construction of functional composite films originating from hemicellulose reinforced with poly(vinyl alcohol) and nano-ZnO

The aim of this study is to prepare functional hemicellulose (HC) films with flexibility, thermoplasticity and UV-shielding ability. HC was firstly esterified with vinyl benzoate and then reinforced with poly(vinyl alcohol) (PVA) and nano-zinc oxide (ZnO). After esterification, the solubility of benzoated HC (BH) increased, while the thermal stability decreased. Moreover, esterification could transform HC into crystalline nature and endow HC with tunable transition temperature (Tg). Adding equivalent mass of PVA and 1% ZnO increased the thermal stability of BH/PVA/ZnO films. XRD and DSC analyses showed the new crystalline structure and the decreased Tg of films, probably due to the interactions among BH, PVA and ZnO. From SEM, the cross sections of films were dense, rough, and were connected to form the network structure, promoting the uniform insertion of ZnO into the matrix. The films showed moderate tensile strength and good flexibility with the maximum elongation at break of 87.18%. In addition, the water vapor permeability (WVP) and oxygen permeability (OP) values of BH/PVA/ZnO film were 2.08 × 10−10 g/m s Pa and 0.95 cm3 μm/m2 d kPa, respectively. Moreover, the film with 1% ZnO exhibited excellent UV-shielding properties with the percentage blocking of UV-A and UV-B of 99.34% and 99.99%, respectively.

Experimental investigations on natural fiber embedded additive manufacturing-based biodegradable structures for biomedical applications

PurposeThe purpose of this paper is to explore and investigate the mechanical as well as bacterial characteristics of chemically treated waste natural fiber inserted three-dimensional structures (NFi3DS) produced with fused filament deposition (FFD) for biomedical applications.Design/methodology/approachIn this work, a novel approach has been used for developing the customized porous structures particularly for scaffold applications. Initially, raw animal fibers were collected, and thereafter, the chemical treatment has been performed for making their wise utility in biomedical structures. For this purpose, silk fiber and sheep wool fibers were used as laminations, whereas polylactic acid was used as matrix material. A low-cost desktop time additive manufacturing setup was used for making the customized and porous parts by considering type of fiber, number of laminates, infill density and raster angle as input parameters.FindingsThe results obtained after using design of experimental technique highlighted that output characteristics (such as dimensional accuracy, hardness, three-point bending strength and bacterial test) are influenced by input parameters, as reported in the obtained signal/noise plots and analysis of variance. Optimum level of input parameters has also been found through Taguchi L9 orthogonal array, for single parametric optimization, and teaching learning-based algorithm and particle swarm optimization, for multiple parametric optimization. Overall, the results of the studies supported the use of embedded structures for scaffold-based biomedical applications.Research limitations/implicationsPresently, NFi3DS were produced by using the hand-lay-based manual approach that affected the uniform insert’s distribution and thickness. It is advised to use the automatic fiber placement system, synced with a three-dimensional printer, to achieve greater geometrical precision.Practical implicationsAs both natural fibers and polymer matrix used in this work are well established for their biological properties, hence the methodology explored in this work will help the practitioners/academicians in developing highly compatible scaffold structures.Social implicationsThe present work defines a new practice where the researchers can use natural fibers to reduce the cost associated with fabrication of customized scaffold prints.Originality/valueThe development of natural fiber embedded FFD-based structures is not yet explored for their feasibility in biomedical applications.

Development of a Functionally Equivalent Model of the Mitral Valve Chordae Tendineae Through Topology Optimization.

Ischemic mitral regurgitation (IMR) is a currently prevalent disease in the US that is projected to become increasingly common as the aging population grows. In recent years, image-based simulations of mitral valve (MV) function have improved significantly, providing new tools to refine IMR treatment. However, clinical implementation of MV simulations has long been hindered as the in vivo MV chordae tendineae (MVCT) geometry cannot be captured with sufficient fidelity for computational modeling. In the current study, we addressed this challenge by developing a method to produce functionally equivalent MVCT models that can be built from the image-based MV leaflet geometry alone. We began our analysis using extant micron-resolution 3D imaging datasets to first build anatomically accurate MV models. We then systematically simplified the native MVCT structure to generate a series of synthetic models by consecutively removing key anatomic features, such as the thickness variations, branching patterns, and chordal origin distributions. In addition, through topology optimization, we identified the minimal structural complexity required to capture the native MVCT behavior. To assess the performance and predictive power of each synthetic model, we analyzed their performance by comparing the mismatch in simulated MV closed shape, as well as the strain and stress tensors, to ground-truth MV models. Interestingly, our results revealed a substantial redundancy in the anatomic structure of native chordal anatomy. We showed that the closing behavior of complete MV apparatus under normal, diseased, and surgically repaired scenarios can be faithfully replicated by a functionally equivalent MVCT model comprised of two representative papillary muscle heads, single strand chords, and a uniform insertion distribution with a density of 15 insertions/cm2. Hence, even though the complete sub-valvular structure is mostly missing in in vivo MV images, we believe our approach will allow for the development of patient-specific complete MV models for surgical repair planning.

Experimental and numerical investigation on heat transfer augmentation in a circular tube under forced convection with annular differential blockages/inserts

Investigation on heat transfer by generating turbulence in the fluid stream inside the circular tube is an innovative area of research for researchers. Hence, many techniques are been investigated and adopted for enhancement of heat transfer rate to reduce the size and the cost of the heat exchanger/circular tube. In the present study the effect of differential solid ring inserts /turbulators on heat transfer, friction factor of heat exchanger/circular tube was evaluated through experimentally and numerically. The experiments were conducted in range of 3000 ≤Re≤ 6500 and annular blockages 0 ≤ɸ≤50 %. The heat transfer rate was higher for differential combination of inserts as compared to tube fitted with uniform inserts. The maximum heat transfer was obtained by the use of differential metal circular ring inserts/blockages. From this study, Nusselt number, friction factor and enhancement factor are found as 2.5-3.5 times, 12% - 50.5% and 155% - 195%, respectively with water. Finally new possible correlations for predicting heat transfer and friction factor in the flow of water through the circular tube with differential blockages/inserts are proposed.

Selective debenzylation of 1-benzyloxy-4-methoxy benzene over 5-sulfosalicylic acid-functionalized ordered mesoporous silica (SBA-15/SFSA) catalyst

5-Sulfosalicylic acid (SFSA) functionalized mesoporous silica nanocomposites (SBA/APTS/SFSA) were synthesized by post grafting technique for selective debenzylation of 1-benzyloxy-4-methoxy benzene. The uniform incorporation of SFSA inside the mesoporous SBA-15 framework was confirmed by standard characterization techniques (PXRD, adsorption studies, FT-IR, etc.). Total surface area, pore size and pore volume of the SBA/APTS/SFSA catalysts decreased with increase in the concentration of SFSA confirming the uniform insertion of SFSA into mesoporous SBA-15 matrix. Catalytic activity studies showed highest conversion and selectivity of the desired product on SBA/APTS/SFSA catalyst compared to homogeneous SFSA and other solid support (Al2O3 and SiO2). All the reaction parameters such as reaction time, reaction temperature and catalyst weight were optimized under environmental friendly conditions. Finally, the possible mechanism of the reaction was explained.

Dynamic analysis of the mesenchymal-epithelial transition of blood-brain barrier forming glia in Drosophila.

ABSTRACTDuring development, many epithelia are formed by a mesenchymal-epithelial transition (MET). Here, we examine the major stages and underlying mechanisms of MET during blood-brain barrier formation in Drosophila. We show that contact with the basal lamina is essential for the growth of the barrier-forming subperineurial glia (SPG). Septate junctions (SJs), which provide insulation of the paracellular space, are not required for MET, but are necessary for the establishment of polarized SPG membrane compartments. In vivo time-lapse imaging reveals that the Moody GPCR signaling pathway regulates SPG cell growth and shape, with different levels of signaling causing distinct phenotypes. Timely, well-coordinated SPG growth is essential for the uniform insertion of SJs and thus the insulating function of the barrier. To our knowledge, this is the first dynamic in vivo analysis of all stages in the formation of a secondary epithelium, and of the key role trimeric G protein signaling plays in this important morphogenetic process.

Influence of Anion Structure of Ionic Liquid on the Electrochemical Performance of Si-Based Negative Electrode for Li-Ion Battery

To use Li-ion battery as a power source in electric vehicles and stationary power supply systems, an additional increase in its energy density is required. While silicon (Si) is a promising active material for use as a negative electrode due to its high theoretical capacity, higher energy density leads to an increase in a risk of ignition of the battery. Electrolyte is one of the most important component determining the battery performance. Ionic liquids have received much attention as an alternative to a conventional organic electrolytes because of their excellent physicochemical properties, such as high thermal stability, negligible vapor pressure, and wide electrochemical window. We have previously reported that the electrochemical performance of Si electrode in ionic liquid electrolyte is superior to that in organic electrolyte,1 and that an initial charge-discharge capacity of Si electrode increases when ether groups is introduced to side chain of cation in ionic liquid; cation structure of ionic liquid influences the electrochemical performance of Si negative electrode.2 Anion of ionic liquid is also key factor because it should affect the solvation structure of Li+. However, the anion structure of ionic liquid has not yet been optimized. In this study, we investigated the effect of anion structure of ionic liquid on the electrochemical performance of Si negative electrode for Li-ion battery. Si electrode was prepared by a gas-deposition method, which is without any binder or conductive agent. We assembled 2032-type coin cell consisted of the fabricated Si electrode as working electrode, Li foil as counter electrode, and glass fiber filter as separator. The ionic liquid used in this study consists of 1-((2-methoxyethoxy)methyl)-1-methylpiperidinium (PP1MEM) cation and three types of anion, including bis(fluorosulfonyl)amide (FSA), bis(trifluoromethanesulfonyl)amide (TFSA), and tetrafluoroborate (BF4). The electrolyte solution used was 1 mol dm-3 LiX-dissolved in PP1MEM-X (X: FSA, TFSA, BF4); anion of Li salt was same as that of ionic liquid. 1 mol dm-3 TFSA in propylene carbonate (PC) was also used for comparison. A galvanostatic charge-discharge test was carried out in the voltage range between 0.005 and 2.000 V at 303 K under a current density of 0.42 A g-1 (0.12 C). The conductivity of ionic liquid electrolytes was investigated by an electrochemical impedance spectroscopic analysis in the frequency of 100 kHz to 500 Hz with amplitude of 10 mV. An initial discharge capacity of Si electrode was less than 800 mA h g-1 in BF4-based electrolyte solution. The cycle performance of Si electrode in BF4-based electrolyte was almost the same as that in PC-based electrolyte; the discharge capacity was about 170 mA h g-1 at 80th cycle in both electrolytes. In FSA- and TFSA-based electrolytes, on the other hand, Si negative electrode exhibited high initial discharge capacity of ca. 3000 mA h g-1. It is well-known that surface film is formed on the Si electrode during an initial charging process through the reductive decomposition of the electrolyte, and that the film works as protective film which prevent continuous decomposition of the electrolyte. Better cycle performance of Si electrode in FSA- and TFSA-based electrolytes should be arising from more protective film compared to the film formed in BF4- and PC-based electrolytes. In addition, the disintegration of Si electrode would be suppressed because of the uniform Li insertion into the Si electrode over the entire surface in these electrolytes.3 Si negative electrode showed an excellent high-rate performance in FSA-based electrolyte; a reversible capacity of 800 mA h g-1 was achieved even at the high current density of 6 C, while Si electrode showed the discharge capacity of 100 mA h g-1 in TFSA-based electrolyte. Conductivity of FSA-based electrolyte (2.06 mS cm-1) is more than tripled compared to that of TFSA-based electrolyte (0.66 mS cm-1). Consequently, it is considered that the conductivity significantly affects the rate performance. References 1) H Usui, T. Masuda, and H. Sakaguchi, Chem. Lett., 41(2012) 521. 2) M. Shimizu, H. Usui, K. Matsumoto, T. Nokami, T. Itoh, and H. Sakaguchi, J. Electrochem. Soc., 161(2014) A1765. 3) M. Shimizu, H. Usui, T. Suzumura, and H. Sakaguchi, J. Phys. Chem. C., 119 (2015) 2975. Acknowledgment This work was partially supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI, Grant-in-Aid for Scientific Research B (Grant 24350094).

Loss of PodJ in Agrobacterium tumefaciens Leads to Ectopic Polar Growth, Branching, and Reduced Cell Division.

Agrobacterium tumefaciens is a rod-shaped Gram-negative bacterium that elongates by unipolar addition of new cell envelope material. Approaching cell division, the growth pole transitions to a nongrowing old pole, and the division site creates new growth poles in sibling cells. The A. tumefaciens homolog of the Caulobacter crescentus polar organizing protein PopZ localizes specifically to growth poles. In contrast, the A. tumefaciens homolog of the C. crescentus polar organelle development protein PodJ localizes to the old pole early in the cell cycle and accumulates at the growth pole as the cell cycle proceeds. FtsA and FtsZ also localize to the growth pole for most of the cell cycle prior to Z-ring formation. To further characterize the function of polar localizing proteins, we created a deletion of A. tumefaciens podJ (podJAt). ΔpodJAt cells display ectopic growth poles (branching), growth poles that fail to transition to an old pole, and elongated cells that fail to divide. In ΔpodJAt cells, A. tumefaciens PopZ-green fluorescent protein (PopZAt-GFP) persists at nontransitioning growth poles postdivision and also localizes to ectopic growth poles, as expected for a growth-pole-specific factor. Even though GFP-PodJAt does not localize to the midcell in the wild type, deletion of podJAt impacts localization, stability, and function of Z-rings as assayed by localization of FtsA-GFP and FtsZ-GFP. Z-ring defects are further evidenced by minicell production. Together, these data indicate that PodJAt is a critical factor for polar growth and that ΔpodJAt cells display a cell division phenotype, likely because the growth pole cannot transition to an old pole. How rod-shaped prokaryotes develop and maintain shape is complicated by the fact that at least two distinct species-specific growth modes exist: uniform sidewall insertion of cell envelope material, characterized in model organisms such as Escherichia coli, and unipolar growth, which occurs in several alphaproteobacteria, including Agrobacterium tumefaciens Essential components for unipolar growth are largely uncharacterized, and the mechanism constraining growth to one pole of a wild-type cell is unknown. Here, we report that the deletion of a polar development gene, podJAt, results in cells exhibiting ectopic polar growth, including multiple growth poles and aberrant localization of cell division and polar growth-associated proteins. These data suggest that PodJAt is a critical factor in normal polar growth and impacts cell division in A. tumefaciens.