bluuebunny/crossref_metadata_2025 huggingface dataset:
DNA topology and adaptation of
salmonella typhimurium
to an intracellular environment
Authors: Marshall David G. , Bowe Frances , Hale Christine , Dougan Gordon , Dorman Charles J.
Published: July 2002

The expression of genes coding for determinants of DNA topology in the facultative intracellular pathogen
Salmonella typhimurium
was studied during adaptation by the bacteria to the intracellular environment of J774A.1 macrophage–like cells. A reporter plasmid was used to monitor changes in DNA supercoiling during intracellular growth. Induction of the
dps
and
spv
genes, previously shown to be induced in the macrophage, was detected, as was expression of genes coding for DNA gyrase, integration host factor and the nucleoid–associated protein H–NS. The
top
A gene, coding for the DNA relaxing enzyme topoisomerase I, was not induced. Reporter plasmid data showed that bacterial DNA became relaxed following uptake of
S. typhimurium
cells by the macrophage. These data indicate that DNA topology in
S. typhimurium
undergoes significant changes during adaptation to the intracellular environment. A model describing how this process may operate is discussed.
Xwnt11and the regulation of gastrulation inXenopus
Authors: Smith J.C. , Conlon Frank L. , Saka Yasushi , Tada Masazumi
Published: July 2002

The molecular basis of gastrulation is poorly understood. In this paper we address this problem by taking advantage of the observation that the transcription activator Brachyury is essential for gastrulation movements inXenopusand mouse embryos. We infer from this observation that amongst the target genes of Brachyury are some that are involved in the regulation of gastrulation. In the course of a screen for Brachyury targets we identifiedXwnt11. Use of a dominant-negative Xwnt11 construct confirms that signalling by this class of Wnts is essential for normal gastrulation movements, and further investigation suggests that Xwnt11 signals not through the canonical Wnt signalling pathway involving GSK-3 and β-catenin but through another route, which may require small GTPases such as Rho and Rac. Future work will concentrate on elucidating the Xwnt11 signal transduction pathway and on investigating its influence on cell shape and polarity duringXenopusgastrulation.
The overlapping roles of the inner ear and lateral line: the active space of dipole source detection
Authors: Braun Christopher B. , Coombs Sheryl
Published: July 2002

The problems associated with the detection of sounds and other mechanical disturbances in the aquatic environment differ greatly from those associated with airborne sounds. The differences are primarily due to the incompressibility of water and the corresponding increase in importance of the acoustic near field. The near field, or hydrodynamic field, is characterized by steep spatial gradients in pressure, and detection of the accelerations associated with these gradients is performed by both the inner ear and the lateral line systems of fishes. Acceleration–sensitive otolithic organs are present in all fishes and provide these animals with a form of inertial audition. The detection of pressure gradients, by both the lateral line and inner ear, is the taxonomically most widespread mechanism of sound–source detection amongst vertebrates, and is thus the most likely primitive mode of detecting sound sources. Surprisingly, little is known about the capabilities of either the lateral line or the otolithic endorgan in the detection of vibratory dipole sources. Theoretical considerations for the overlapping roles of the inner ear and lateral line systems in midwater predict that the lateral line will operate over a shorter distance range than the inner ear, although with a much greater spatial resolution. Our empirical results of dipole detection by mottled sculpin, a benthic fish, do not agree with theoretical predictions based on midwater fishes, in that the distance ranges of the two systems appear to be approximately equal. This is almost certainly as a result of physical coupling between the fishes and the substrate. Thus, rather than having a greater active range, the inner ear appears to have a reduced distance range in benthic fishes, and the lateral line distance range may be concomitantly extended.
The ectodermal placodes: a dysfunctional family
Authors: Begbie Jo , Graham Anthony
Published: July 2002

The ectodermal placodes are focal thickenings of the cranial embryonic ectoderm that contribute extensively to the cranial sensory systems of the vertebrates. The ectodermal placodes have long been thought of as representing a coherent group, which share a developmental and evolutionary history. However, it is now becoming clear that there are substantial differences between the placodes with respect to their early development, their induction and their evolution. Indeed, it is now hard to consider the ectodermal placodes as a single entity. Rather, they fall into a number of distinct classes and it is within each of these that the members share a common development and evolution.
Developmental genetic evidence for a monophyletic origin of the bilaterian brain
Authors: Reichert Heinrich , Simeone Antonio
Published: July 2002

The widely held notion of an independent evolutionary origin of invertebrate and vertebrate brains is based on classical phylogenetic, neuroanatomical and embryological data. The interpretation of these data in favour of a polyphyletic origin of animals brains is currently being challenged by three fundamental findings that derive from comparative molecular, genetic and developmental analyses. First, modern molecular systematics indicates that none of the extant animals correspond to evolutionary intermediates between the protostomes and the deuterostomes, thus making it impossible to deduce the morphological organization of the ancestral bilaterian or its brain from living species. Second, recent molecular genetic evidence for the body axis inversion hypothesis now supports the idea that the basic body plan of vertebrates and invertebrates is similar but inverted, suggesting that the ventral nerve chord of protostome invertebrates is homologous to the dorsal nerve cord of deuterostome chordates. Third, a developmental genetic analysis of the molecular control elements involved in early embryonic brain patterning is uncovering the existence of structurally and functionally homologous genes that have comparable and interchangeable functions in key aspects of brain development in invertebrate and vertebrate model systems. All three of these findings are compatible with the hypothesis of a monophyletic origin of the bilaterian brain. Here we review these findings and consider their significance and implications for current thinking on the evolutionary origin of bilaterian brains. We also preview the impact of comparative functional genomic analyses on our understanding of brain evolution.
Dynamical characterization of residual and non‐native structures in a partially folded protein by 15N NMR relaxation using a model based on a distribution of correlation times
Authors: Ochsenbein Françoise , Neumann Jean‐Michel , Guittet Eric , Van Heijenoort Carine
Published: July 2002

A spectral density model based on a truncated lorentzian distribution of correlation times is used to analyze the nanosecond time‐scale dynamics of the partially unfolded domain 2 of annexin I from its 15N NMR relaxation parameters measured at three magnetic field strengths. The use of a distribution of correlation times enables the characterization of the dynamical features of the NH bonds of the protein in terms of heterogeneity of dynamical states in the nanosecond range. The variation along the sequence of the two dynamical parameters introduced, namely the center and the width of the distribution, points out the different types of residual secondary structures present in the D2 domain. Moreover, it allows a physically sensible interpretation of the dynamical behavior of the different residual helices and of the non‐native structures. Also, a striking correspondence is found between the parameters obtained using an extended Lipari and Szabo model and the parameters obtained using the distribution of correlation times. This result led us to propose a specific interpretation of the model‐free order parameter for internal motions in the nanosecond range in the case of unfolded states.
Automated algorithm for the identification of joint space and phalanx margin locations on digitized hand radiographs
Authors: Duryea J. , Jiang Y. , Countryman P. , Genant H. K.
Published: July 2002

Rheumatoid arthritis (RA) of the hand can be characterized and assessed by the narrowing of the joint spaces which are ordinarily scored semiquantitatively by a radiologist using radiographs of the hand. Software which delineates and measures the joint spaces would be a useful tool for assessment. The first part of such an algorithm has been developed which determines the locations of the distal interphalangeal (DIP), proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joint spaces for fingers 2–5 (index, middle, ring, and little) on digitized hand radiographs. In addition, points on the medial and lateral margins of each phalanx are identified which can be used as starting points for edge detection algorithms to provide segmentation of the phalanges. The algorithm is a C‐language program running on a UNIX computer, uses a multiresolution approach operating, and requires approximately 10 CPU seconds per image. It was tested on a set of 54 radiographs taken from a multicenter rheumatoid arthritis study where a study protocol was followed. In addition, radiographs of individuals wearing rings and where nonanatomical structures contacted the anatomy proximal to the midpoint of the distal phalanx and distal to the MCP joint were eliminated from the data set. In order to make a quantitative assessment, regions of interest drawn by a trained radiologist were used as a gold standard. The algorithm had a success rate of 100% for the identification of each digit and over 99% for the identification of joint space locations and phalanx margins. Quantitative tests indicated excellent algorithm robustness. We have developed fully automated software which accurately identifies anatomical landmarks on digital images of the hand.
General series solution for finite square-well energy levels for use in wave-packet studies
Authors: Aronstein David L. , Stroud C. R.
Published: July 2002

We develop a series solution for the bound-state energy levels of the quantum-mechanical one-dimensional finite square-well potential. We show that this general solution is useful for local approximations of the energy spectrum (which target a particular energy range of the potential well for high accuracy), for global approximations of the energy spectrum (which provide analytic expressions of reasonable accuracy for the entire range of bound states), and for numerical methods. This solution also provides an analytic description of dynamical phenomena; with it, we compute the time scales of classical motion, revivals, and super-revivals for wave-packet states excited in the well.
Listening to the coefficient of restitution - revisited
Authors: Stensgaard I. , Lægsgaard E.
Published: July 2002

We present a new method for measuring the coefficient of restitution between a steel ball and a flat, smooth surface, based on the recording of sound files with a PC. We demonstrate how a simple and straightforward analysis of the sound files yields the coefficient of restitution as a function of velocity. The time resolution of many PC sound cards allows us to measure the collision time and hence to estimate the average impulsive force and the stress exerted on the surface. This in turn provides a basis for a discussion of energy loss mechanisms.
Bessel’s improved Kater pendulum in the teaching lab
Authors: Candela D. , Martini K. M. , Krotkov R. V. , Langley K. H.
Published: July 2002

We describe a Bessel pendulum for use in the teaching laboratory, and measurements of the local acceleration of gravity made with it to an accuracy of better than one part in 104. The Bessel pendulum is a reversible pendulum that eliminates atmospheric corrections that apply to the more familiar Kater pendulum. The physical principles underlying the Kater pendulum as well as Bessel’s refinement are reviewed, and construction details are given for a realization of the pendulum.
Case study of the physics component of an integrated curriculum
Authors: Beichner R. , Bernold L. , Burniston E. , Dail P. , Felder R. , Gastineau J. , Gjertsen M. , Risley J.
Published: July 2002

Over a four-year time span, several departments at North Carolina State University offered experimental sections of courses taken by freshman engineering students. The acronym IMPEC (Integrated Math, Physics, Engineering, and Chemistry curriculum) describes which classes were involved. This paper discusses the physics component of the curriculum and describes the impact of the highly collaborative, technology-rich, activity-based learning environment on a variety of conceptual and problem-solving assessments and attitude measures. Qualitative and quantitative research results indicate that students in the experimental courses outperformed their cohorts in demographically matched traditional classes, often by a wide margin. Student satisfaction and confidence rates were remarkably high. We also noted substantial increases in retention and success rates for groups underrepresented in science, math, and engineering. Placing students in the same teams across multiple courses appears to have been the most beneficial aspect of the learning environment.
Entropy and time
Authors: Ambegaokar Vinay , Clerk Aashish A.
Published: July 2002

The emergence of a direction of time in statistical mechanics from an underlying time-reversal-invariant dynamics is explained by examining a simple model. The manner in which time-reversal symmetry is preserved and the role of initial conditions are emphasized. An extension of the model to finite temperatures also is discussed.
The effect of moisture on compressional and shear wave speeds in unconsolidated granular material
Authors: Shields F. Douglas , Sabatier James M. , Wang Mark
Published: July 2002

The effect of water vapor on the shear and compressional wave speeds in two different kinds of glass beads and in Ottawa sand has been measured. The nominal diameter of the glass beads was 125 μm and of the sand, 500 μm. Measurements were made as the water vapor was introduced slowly into the evacuated material. The vapor pressure isotherm for the beads made of glass with a high concentration of titanium and barium oxides was fit reasonably well by the simple Brunauer–Emmett–Teller (BET) theory. For the Ottawa sand, the BET theory fit the vapor pressure isotherm if the surface area of the grains was assumed to be three times the area calculated, assuming all of the grains were spheres with a diameter of 500 μm. In these two materials, the vapor had little effect on the wave speeds. For beads made of glass containing sodium oxide, however, the wave speeds approximately double with the introduction of water vapor, and the vapor pressure isotherm had the BET shape only if the saturated vapor pressure was assumed to be lowered by 20%. These results have been explained by assuming that a chemical reaction occurred between the lime glass and the water to form a gel.
Field characterization of an air-coupled micromachined ultrasonic capacitance transducer
Authors: Bashford A. G. , Schindel David W. , Hutchins David A. , Wright W. M. D.
Published: July 2002

Investigations into the field characteristics of an air-coupled ultrasonic capacitance transducer have been performed for a range of transducer configurations. The field of a 2-MHz bandwidth silicon backplate capacitance transducer has been scanned in air using a 1-mm-diam miniature detector at frequencies of up to 1.5 MHz. The radiated peak sound-pressure field is compared to theory based on a plane piston approach for various driving signals, namely pulsed and tone burst excitation. Aperture modifications, such as an annulus and a zone plate, have also been investigated and the devices have been shown to behave as predicted by theory.
Bioacoustic behavior of African fishes (Mormyridae): Potential cues for species and individual recognition in Pollimyrus
Authors: Crawford John D. , Cook Aaron P. , Heberlein Andrea S.
Published: July 2002

An analysis of the natural bioacoustic signals made by two closely related African fishes (P. adspersus and P. isidori) revealed that these species separated along several acoustic dimensions that are likely to be important for species isolation. Both species produced grunts that were composed of a trains of pulses, but the pulse repetition rates were distinctly different (56±3 s.d. vs 44±4 s.d. pps). Complex tone bursts (moans) were also used, but the species differed substantially in the location of the fundamental peak (240 Hz±12 s.d. vs 332 Hz±34 s.d.). Some P. adspersus males sustained these tones for over a second (812 ms±495 s.d.), whereas P. isidori produced shorter tones (121 ms±35 s.d.). During interactions with females, the two species produced the grunts and moans in distinct species-typical patterns: P. adspersus males alternated grunts with moans and P. isidori produced a single grunt followed by a succession of moans. A detailed analysis of identified individual P. adspersus showed that acoustic features constituted individual signatures which could be used by conspecifics to identify individuals. Grunt spectral peak frequency was shown to be a good predictor of male mass, with peak frequency decreasing at 72 Hz per gram. Simulated standardized courtship encounters with females revealed that males differ markedly in their apparent ability to produce sustained moans and it is suggested that this may be particularly important to females in mate selection.
A simplified method for determining sediment size and concentration from multiple frequency acoustic backscatter measurements
Authors: Thosteson Eric D. , Hanes Daniel M.
Published: July 2002

Until recently the determination of concentration from acoustic backscatter intensity measurements required an iterative technique due to the implicit form of the acoustic backscatter equation. In this paper, an explicit form of this equation is examined in an effort to simplify the technique of determining size from multifrequency acoustic backscatter data. By retaining the size dependence throughout the derivation for an explicit solution for concentration, a new explicit form results. This new explicit concentration solution improves the technique for determining median sediment size by incorporating sediment attenuation in the calculation. Because this new technique relies on the minimization of the variance in concentration as determined by different frequency transducers, the previous technique of pairing transducers of different frequencies is replaced by a technique making use of any number of different frequency transducers. The new size/concentration inversion technique is tested using both simulated and laboratory data. Numerical precision is shown to be the only source of error with the use of simulated data. Laboratory tests result in less than 20% error in the determination of both concentration and size over a range of nearly one meter.
Shock waves from cavitation bubbles
Authors: Lauterborn Werner , Kurz Thomas , Schenke Cordt , Ohl Claus-Dieter , Geisler Reinhard , Lindau Olgert
Published: July 2002

Cavitation bubbles are produced in water by focused laser light with pulse durations in the 100-fs and 10-ns range. Special attention is paid to the shock waves during breakdown and first collapse of the bubble or bubbles generated. The special focusing properties of femtosecond pulses lead to cylindrical shock waves from elongated breakdown channels and to more complicated shock wave patterns in the pre-breakdown region. Bubble collapse leads to spherical outgoing shock waves in the case of spherical shrinking of the bubble and to a sequence of distinct shock waves in the case of aspherical shrinking. The shock waves are made visible with shadowgraph techniques, including femtosecond pulses for illumination, and are measured with a fiberoptic hydrophone. [Work supported by the Deutsche Forschungsgemeinschaft.]
Festspielhaus Bayreuth—The unique acoustic situation
Authors: Müller Karlheinz
Published: July 2002

The Festspielhaus in Bayreuth is the only opera house of the world which was founded and mostly designed by a composer. Richard Wagner himself founded the festival society and was one of the main designers of the opera house, the stage situation, and the pit. It is a very modern opera house, far away from the typical aristocratic or common theater of the times of 1876. The open house has a special acoustic situation. What are the reasons for this acoustic situation? Especially the sunken-pit design is subject to endless controversial discussions. All the maintenance work of the last years had the priority not to destroy the typical mysterious sound of the original Festspielhaus. Although all part of the whole house are now redecorated, the typical Wagnerian sound has been perfectly conserved.
Comparison of theoretical and experimental ultrasonic velocity in three-component mixtures of methyl ethyl ketone and toluene with n-alkanols and estimation of acoustic nonlinearity parameter (B/A)
Authors: Abraham Roshan , Abdul Khadar M. , Jugan J.
Published: July 2002

A theoretical estimation of ultrasonic velocity using Flory–Patterson theory (FPT), Jacobson’s free length theory, Schaaffs’ collision factor theory, Nomoto’s relation, and Van Dael’s ideal mixture relation (IMR) has been done in the three-component (ternary) mixtures of methyl ethyl ketone and toluene with n-alkanols. The theoretically predicted ultrasonic velocities are compared with the experimentally determined velocities in the ternary mixtures at 30 °C. It is found that the velocities evaluated using all the theories except FPT and IMR are in fairly good agreement with the experimental velocity values. Acoustic nonlinearity parameter (B/A) and a few thermodynamic parameters have been evaluated theoretically for the ternary mixtures using the Tong and Dong equation combined with Flory’s statistical theory and its extended version to ternary mixtures.
Sparse array technology for 3-D sonar imaging systems
Authors: Impagliazzo John M. , Kay Steven M. , Chiang Alice M. , Broadstone Steven R.
Published: July 2002

A three-dimensional sonar imaging system is under development for use by Navy divers for mine-field reconnaissance and mine-hunting systems. Divers require a small, low-power, lightweight acoustic imaging system with high resolution for examining and disposing of underwater ordinance. Sparse array technology is investigated to develop a sonar requiring the minimal number of signal processing channels while maintaining the beamwidth and sidelobe structure required for high-resolution imaging. Beamwidth and sidelobe structure are examined as a function of transducer element count, channel bandwith, and element location when optimized using various cost functions. Locally optimum solutions are computed for uniformly weighted sparse arrays. Cost functions evaluated for the optimization process compute average sidelobe energy, peak sidelobe energy and a weighted average sidelobe energy. Images will be formed using multiple CCD/CMOS time-delay beamforming circuits to compute the large number of beams required to provide a real-time high-resolution image.
Influence of primary frequencies ratio on distortion product otoacoustic emissions amplitude. I. Intersubject variability and consequences on the DPOAE-gram
Authors: Moulin A.
Published: July 2002

Distortion product otoacoustic emissions (DPOAEs) are used widely in humans to assess cochlear function. The standard procedure consists of recording the 2f1-f2 DPOAE amplitude as a function of the f2 frequency, using a fixed f2/f1 ratio (DPOAE-gram), close to 1.20. DPOAE amplitude, as recorded in the DPOAE-gram, shows a wide range of values in normal-hearing subjects, which can impair the predictive value of the DPOAE-gram for hearing thresholds. This study is aimed at comparing intersubject variability in 2f1-f2 DPOAE amplitude according to three paradigms: a fixed f2/f1 ratio, such as the DPOAE-gram, a variable ratio DPOAE-gram (f2/f1 adapted to frequency) and an “optimum” DPOAE-gram, where the f2/f1 is adapted both to subject and frequency. The 2f1-f2 DPOAE amplitude has been investigated on 18 normally hearing subjects at ten different f2 frequencies (from 0.75 to 6 kHz), using an f2 fixed, f1 sweep paradigm, and allowed to define, for each frequency, the f2/f1 ratio giving the greatest 2f1-f2 DPOAE amplitude (or optimum ratio). Results showed a large intersubject variability of the optimum ratio, especially at frequencies below 1.5 kHz, and a significant decrease of the optimum ratio with frequency. The optimum DPOAE-gram was underestimated by up to 5.8 dB on average (up to 14.9 dB for an individual subject) by the fixed ratio DPOAE-gram, and by up to 3 dB on average (up to 10.6 dB for an individual subject) by the variable ratio DPOAE-gram. Intersubject variability was slightly but significantly reduced in the optimum DPOAE-gram versus the fixed-ratio DPOAE-gram. Lastly, correlations between tone-burst evoked otoacoustic emission (TBOAE) amplitudes and maximum DPOAE amplitudes were significantly greater than correlations between TBOAE amplitudes and fixed-ratio DPOAE amplitudes.
Rheological Properties of Molten Polymers. II. Creep Function of Commercial Polystyrene
Authors: Karam Henry J. , Hyun Kun S. , Bellinger John C.
Published: July 2002

This paper describes an experimental technique for determining visocelastic constants for molten polymers by tensile creep experiments. The constants determined were retardation times, shear compliances, zero-shear flow viscosity, and shift factors. Data are given in terms of a generalized Voigt model. Polymers evaluated were several commercial polystyrenes. Experimental data indicate that the creep curves obtained at different temperatures do not exactly shift according to the time-temperature superposition principle. A possible explanation of the discrepancy is proposed in the paper. Shift factors as obtained by creep experiments are compared with calculated values obtained by the WLF equation. Agreement is poor. However, the general expression of WLF type is applicable in correlating shift factors as a function of temperature. New sets of constants are obtained for polystyrene samples. Activation energy of polystyrene due to viscoelastic deformation is compared with the activation energy due to viscous flow deformation. For temperatures greater than 120 °C, the values obtained by the two types of deformation are equal, however, for temperatures lower than 120 °C, the activation energy due to viscoelastic deformation is much greater than viscous deformation. The activation energy obtained for viscoelastic deformation at lower temperatures agrees with values by retraction studies and birefringence measurements.
Full tensor optical rheometry of polymer fluids
Authors: Kalogrianitis Socratis G. , van Egmond Jan W.
Published: July 2002

A novel three-dimensional flow birefringence technique has been developed to measure the real time, three-dimensional, optical anisotropy in flowing polymer solutions. Full tensor optical rheometry utilizes three polarization-modulated beams to probe all independent elements of the refractive index tensor and is, thus, used as a quantitative probe of time-dependent, three-dimensional average molecular orientation. We present results for shear flow of polystyrene in a 6% semidilute solution of tricresyl phosphate over a range of shear rates. Although the time-dependent behavior of N2 has not been widely reported, probably because of experimental difficulties, it can be a powerful means of testing rheological models. Experimental measurements of the transient behavior of N2 and −N2/N1 on inception and cessation of simple shear flow are compared with the predictions of the Doi–Edwards and Giesekus models. The Giesekus model is in qualitative agreement with most of the time-dependent features observed for N2 and −N2/N1. On-flow inception overshoots in N2 and −N2/N1 are observed. Further, on-flow cessation, N2 relaxes more slowly than N1 and −N2/N1 shows a strong nonexponential increase to a constant value of ∼0.9 at long times. The Doi–Edwards model is less successful in predicting transient results but agrees quite well with observed steady-state dependence of N2 with shear rate.
Vehicular Networks and Vehicle‐to‐Infrastructure (V2I) Networking
Authors: Chen Xianhao , Zhu Guangyu , Deng Yiqin , Fang Yuguang
Published: February 2022

Vehicular network is an essential part of the contemporary wireless network, which plays a vital role in intelligent transportation system (ITS). Driven by the ever‐increasing needs for making our lives and cities smart, vehicular network nowadays goes beyond the information exchange among vehicles, transforming to “vehicle‐to‐everything” (V2X). In this article, we present the fundamentals of vehicular networks and vehicle‐to‐infrastructure (V2I) networking, called V2X networking for simplicity. First of all, we start by discussing the emerging use cases for V2X networking, together with their service requirements. Second, we elaborate on several vehicular networking technologies and protocols, with the main focus on dedicated short‐range communications (DSRCs) and cellular V2X. At last, we provide the outlooks for future V2X networks and identify the research challenges.
Electrolyte Optimization and Interphase Regulation for Significantly Enhanced Storage Capability in Ca‐Metal Batteries
Authors: Song Huawei , Li Yan , Tian Fei , Wang Chengxin
Published: February 2022

Electrolyte solvent, salt, and additive directly determine many battery indicators such as voltage limit, safe reliability, and temperature limit. In Ca‐metal batteries, suitable electrolyte and interphase are necessary to achieve reversible calcium plating/stripping, which is challenging for F‐based salts at room temperature. Ion transport and charge transfer in calcium batteries with Ca(BF4)2‐NaPF6 electrolyte are regulated for the first time by altering solvent and salt categories and ratios, achieving adjustable interphase species and microstructure, calcium deposition/dissolution overpotentials, and cycling stability. The optimized electrolyte of 0.1 m Ca(BF4)2‐0.9 m NaPF6 in ethylene carbonate/diethyl carbonate/dimethyl carbonate/ethyl methyl carbonate (7:1:6:6, v/v) contributes to the most stable Ca plating/stripping cycling and the weakest overpotential, as well as Na/Ca‐based hybrid solid electrolyte interphases including proper amount of organic matter. Ca‐metal batteries with the optimized electrolyte achieve an ultrahigh reversible capacity of ≈290 mAh g−1 (at 200 mA g−1 and 1.2–4.5 V), almost four times more than that of counterpart ones (≈65 mAh g−1), equivalent to energy/power performance of ≈616 Wh kg−1 at 429 W kg−1 among the best ones for multivalent ion rechargeable metal batteries.
Intracellular Mechanical Drugs Induce Cell‐Cycle Altering and Cell Death
Authors: Arjona María Isabel , Duch Marta , Hernández‐Pinto Alberto , Vázquez Patricia , Agusil Juan Pablo , Gómez‐Martínez Rodrigo , Redondo‐Horcajo Mariano , Amirthalingam Ezhil , Pérez‐García Lluïsa , Suárez Teresa , Plaza José A.
Published: February 2022

Current advances in materials science have demonstrated that extracellular mechanical cues can define cell function and cell fate. However, a fundamental understanding of the manner in which intracellular mechanical cues affect cell mechanics remains elusive. How intracellular mechanical hindrance, reinforcement, and supports interfere with the cell cycle and promote cell death is described here. Reproducible devices with highly controlled size, shape, and with a broad range of stiffness are internalized in HeLa cells. Once inside, they induce characteristic cell‐cycle deviations and promote cell death. Device shape and stiffness are the dominant determinants of mechanical impairment. Device structural support to the cell membrane and centering during mitosis maximize their effects, preventing spindle centering, and correct chromosome alignment. Nanodevices reveal that the spindle generates forces larger than 114 nN which overcomes intracellular confinement by relocating the device to a less damaging position. By using intracellular mechanical drugs, this work provides a foundation to defining the role of intracellular constraints on cell function and fate, with relevance to fundamental cell mechanics and nanomedicine.
Formation of Linear Oligomers in Solid Electrolyte Interphase via Two‐Electron Reduction of Ethylene Carbonate
Authors: Liu Yue , Wu Yu , Sun Qintao , Ma Bingyun , Yu Peiping , Xu Liang , Xie Miao , Yang Hao , Cheng Tao
Published: February 2022

Solid electrolyte interphase (SEI) plays a significant role in enhancing the stability and durability of lithium metal batteries (LMBs) by separating highly reactive lithium metal anode (LMA) from the electrolyte to avoid continuous degradation. However, the underlying reaction mechanism is still far from clear. Herein, a hybrid ab initio and reactive force field (HAIR) method is employed to extend the ab initio molecular dynamics (AIMD) to 1 ns, which provides crystal information about the reaction mechanism of elementary reactions that can explain the components and morphology evolution of SEI formation. Specifically, HAIR simulation confirms the two‐electron (2e–) reduction of ethylene carbonate (EC) by releasing CO and CO2, agreeing with phenomenal experiment observation. As the unsaturated intermediates accumulate, polymerization reactions occur, producing linear polyethylene oxide (PEO), Li2OCO2CH2CH2, Li2OCO2(CH2)4, etc., which regulate the formation of outer organic layer (OOL) that consists of linear polyethylene oxide (PEO), Li2OCO2CH2CH2, Li2OCO2(CH2)4, etc., and the inner inorganic layer (IIL) mainly consists of LiF and Li2O. Simulations at low concentration (LC, 1M) and high concentration (HC, 5M) reveal significantly different reaction pathways when HC electrolyte can significantly promote the formation of homogenous LiF that has been regarded as an important component to facilitate robust SEI.
Spontaneous Membranization in a Silk‐Based Coacervate Protocell Model
Authors: Yin Zhuping , Tian Liangfei , Patil Avinash J. , Li Mei , Mann Stephen
Published: February 2022

Molecularly crowded coacervate micro‐droplets are useful protocell constructs but the absence of a physical membrane limits their application as cytomimetic models. Auxiliary surface‐active agents have been harnessed to stabilize the coacervate droplets by irreversible shell formation but endogenous processes of reversible membranization have received minimal attention. Herein, we describe a dynamic alginate/silk coacervate‐based protocell model in which membrane‐less droplets are reversibly reconfigured and inflated into semipermeable coacervate vesicles by spontaneous self‐organization of amphiphilic silk polymers at the droplet surface under non‐neutral charge conditions in the absence of auxiliary agents. We show that membranization can be reversibly controlled endogenously by programming the pH within the protocells using an antagonistic enzyme system such that structural reconfigurations in the protocell microstructure are coupled to the trafficking of water‐soluble solutes. Our results open new perspectives in the design of hybrid protocell models with dynamical structural properties.
When influencers are not very influential: The negative effects of social media verification
Authors: Dumas Jazlyn Elizabeth , Stough Rusty Allen
Published: February 2022

As social media usage has grown over the recent past, so too has a new form of celebrity: social media influencers (SMIs). It can be difficult for consumers to know whether the influencers they are following are real. To combat this, social media sites introduced user verification. Verification, denoted by a blue checkmark badge visible in search and on one's profile, is ostensibly a way of confirming one's identity, yet only accounts with large followings are awarded verification status by the platform. In this paper, we investigate the perception of verification in the context of SMIs, a topic relatively absent from the literature despite the billions of dollars spent on partnerships. Specifically, we investigate if consumers perceive verification as more directly associated with credibility or celebrity. Further, we consider whether the fit of the influencer with the advertisement yields discrepancies in consumers' trust of the advertisement and endorser in paid partnerships on social media. Through two studies, we find that consumers associate verification most closely with celebrity, rather than authenticity and that when the influencer is advertising a product that does not fit with their brand, consumers are significantly less likely to trust verified accounts rather than unverified accounts. This study has theoretical implications for marketing researchers as well as practical implications for marketing managers. Verified influencers cost more; therefore, this research provides unique insights for brands to capitalize their ad return if they are made aware of the implications associated with verification.
Management of a radiopaque foreign body associated with a lower first premolar: A case report
Authors: Yagmoor Mohammed , Bakhsh Abdulaziz , Mandourah Olfah , Alsofi Loai
Published: February 2022

Operator mishaps significantly affects root canal treatment outcome. However, several factors affect root canal anatomy of teeth. Therefore, knowledge of teeth anatomy and the use of advanced technologies like cone‐beam computed tomography (CBCT), magnification, and illumination are crucial for better diagnostic purposes and to avoid any procedural errors. In this case report, we present a case of a 32‐year‐old male patient with a radiopaque foreign body associated with a lower first premolar tooth and how do the use of advanced technologies could affect the treatment outcome.
Type S Non‐Ribosomal Peptide Synthetases for the Rapid Generation of Tailormade Peptide Libraries**
Authors: Abbood Nadya , Duy Vo Tien , Watzel Jonas , Bozhueyuek Kenan A. J. , Bode Helge B.
Published: February 2022

Bacterial natural products in general, and non‐ribosomally synthesized peptides in particular, are structurally diverse and provide us with a broad range of pharmaceutically relevant bioactivities. Yet, traditional natural product research suffers from rediscovering the same scaffolds and has been stigmatized as inefficient, time‐, labour‐ and cost‐intensive. Combinatorial chemistry, on the other hand, can produce new molecules in greater numbers, cheaper and in less time than traditional natural product discovery, but also fails to meet current medical needs due to the limited biologically relevant chemical space that can be addressed. Consequently, methods for the high throughput generation of new natural products would offer a new approach to identifying novel bioactive chemical entities for the hit to lead phase of drug discovery programs. As a follow‐up to our previously published proof‐of‐principle study on generating bipartite type S non‐ribosomal peptide synthetases (NRPSs), we now envisaged the de novo generation of non‐ribosomal peptides (NRPs) on an unreached scale. Using synthetic zippers, we split NRPSs in up to three subunits and rapidly generated different bi‐ and tripartite NRPS libraries to produce 49 peptides, peptide derivatives, and de novo peptides at good titres up to 145 mg L−1. A further advantage of type S NRPSs not only is the possibility to easily expand the created libraries by re‐using previously created type S NRPS, but that functions of individual domains as well as domain‐domain interactions can be studied and assigned rapidly.
In Vitro Anticancer Ability of Nano Fluorescent 111In‐MIL‐68/PEG‐FA on Hela Cells
Authors: Liang Ranxi , Liao Zhonghui , Li Feize , Ma Huan , Liu Weihao , Chen Xijian , Lan Tu , Yang Yuanyou , Liao Jiali , Yang Jijun , Liu Ning
Published: February 2022

In past decades, nanoscale metal‐organic frameworks (NMOFs) have drawn more and more attention in multimodal imaging and targeting therapy of various malignant cancers. Here, we proposed to dope 111In into fluorescent In‐based NMOFs (In‐MIL‐68‐NH2), with an attempt to prepare a new nanomedicine with great anticancer potential. As a proof of concept, the obtained NMOF (In‐MIL‐68/PEG‐FA) with targeting motifs is able to act as a fluorescent probe to achieve Hela cell imaging. Moreover, the Auger electron emitter 111In built in corresponding radioactive NMOF (111In‐MIL‐68/PEG‐FA) can bring clear damage to cancer cells, leading to a high cell killing rate of 59.3 % within 48 h. In addition, the cell cycle presented a significant dose‐dependent G2/M inhibiting mode, which indicates that 111In‐MIL‐68/PEG‐FA has the ability to facilitate the cancer cells to enter apoptotic program. This work demonstrated the potential of 111In‐labelled NMOFs in specific killings of cancer cells, providing a new approach to develop nanomedicines with theranostic function.
Privacy information antistealing control method of medical system based on cloud computing
Authors: Yao Yao , Wang Zhanhong
Published: February 2022

With the development of cloud computing, the security of information has gradually become the focus of people. The patient information processed by the medical system has a very high sensitivity and privacy. If there is a leak, it will have a great impact on the patients. The purpose of this study is to explore the privacy information antistealing control method of medical system based on cloud computing. In this paper, through big data analysis, experimental research, variable comparison, and other methods, combined with modern security management means, we carry out the algorithm experiment and research on the privacy information antistealing control means. The result is that the running time of the three algorithms is 18, 16, and 10 s in turn when the algorithm runs 1000 times. It can be seen that the operation time of the enhanced encryption algorithm in this study is less than the initial algorithm by 8 s, the speed is increased by more than 40%. The conclusion is to improve the efficiency of data computing time and make the encryption process more efficient and accurate. The privacy data protection of medical system plays a good role.
Hypotheses and lessons from a native moth outbreak in a low‐diversity, tropical rainforest
Authors: Banko Paul C. , Peck Robert W. , Yelenik Stephanie G. , Paxton Eben H. , Bonaccorso Frank , Montoya‐Aiona Kristina , Hughes R. Flint , Perakis Steven
Published: February 2022

Outbreaks of defoliating insects in low‐diversity tropical forests occur infrequently but provide valuable insights about outbreak ecology in temperate environments and in general. We investigated an extensive outbreak of the endemic koa moth (Scotorythra paludicola), which defoliated endemic koa trees (Acacia koa) over a third of their range on Hawai‘i Island during 2013 and 2014. At Hakalau Forest National Wildlife Refuge, we observed the dynamics of the outbreak and its effects on host trees, nutrient cycling, and insectivorous consumers in reforestation stands of densely planted koa and in natural forest stands of mixed koa and ‘ōhi‘a (Metrosideros polymorpha). Contrary to predictions of the resource concentration hypothesis, caterpillar biomass and defoliation severity were greater in the natural forest sites, where koa density was relatively low. Caterpillars preferentially consumed the most palatable koa foliage type (phyllodes), and koa initially refoliated with the least palatable foliage type (true leaves). Lightly defoliated small trees refoliated more quickly than did heavily defoliated ones but the opposite was true for large trees, which also produced a greater proportion of phyllodes. Mortality was greatest for heavily defoliated small koa. Caterpillar frass caused larger increases in soil nitrogen (N) than phosphorus (P) availability, with the greatest N increases in fine‐textured soils. Foliar N increased in alien grasses under koa canopies compared to grasses away from koa and to native woody understory species. Bird activity was influenced by ‘ōhi‘a flower abundance and the severity of koa defoliation; birds switched to outbreaking caterpillar prey, and they gained weight during the outbreak. Bat foraging times decreased during the outbreak, apparently because they became satiated quickly each night. Parasitoid wasps increased with caterpillar abundance but had little influence on outbreak dynamics. Reducing alien grass cover and increasing tree diversity would likely reduce the impacts of insect outbreaks and similar perturbations to native forests.
Adsorption of Copper Ions onto Poly(1,8‐diaminonaphthalene)/Graphene Film for Voltammetric Determination of Pyridoxine
Authors: Vu Trong V. , Nguyen Mai T. T. , Do Thuy T. , Nguyen Huy L. , Nguyen Vân‐Anh , Nguyen Dzung T.
Published: February 2022

In this work, pyridoxine (vitamin B6) was determined by the square wave voltammetry at copper‐poly(1,8‐diaminonaphthalene)/graphene modified glassy carbon electrode. The composite electrodes were fabricated with two steps. First, poly(1,8‐diaminonaphthalene) is electrodeposited onto graphene/glassy carbon electrodes with a potential cycling technique. Then, copper ions are adsorbed onto the poly(1,8‐diaminonaphthalene)/graphene modified glassy carbon electrode due to the immersion of the polymeric modified electrode in an aqueous copper (II) solution. The characterizations of synthesized materials have shown the role of graphene in facilitating the electron transfer and the remarkably electrocatalytic ability of copper for pyridoxine oxidation on the electrode surface. In 0.1 M phosphate buffer solution (pH 7.4), the peak current of square wave voltammograms of pyridoxine increased linearly with their concentration in the ranges between 0.58 and 24.51 μM with the limit of detection of 0.3 μM. The proposed electrodes showed excellent reproducibility and stability.
The NLRP3 inflammasome modulates tau pathology and neurodegeneration in a tauopathy model
Authors: Stancu Ilie Cosmin , Lodder Chritica , Botella Lucena Pablo , Vanherle Sarah , Gutiérrez de Ravé Manuel , Terwel Dick , Bottelbergs Astrid , Dewachter Ilse
Published: February 2022

An active role of neuroinflammation and the NLRP3 inflammasome in Alzheimer's disease and related tauopathies is increasingly identified, supporting NLRP3 as an interesting therapeutic target. However, its effect on tau‐associated neurodegeneration, a key‐process in tauopathies, remains unknown. While tau pathology and neurodegeneration are closely correlated, different tau forms may act as culprits in both characteristics and NLRP3‐dependent microglial processes may differently affect both processes, indicating the need to study the role of NLRP3 in both processes concomitantly. To study the role of NLRP3 on tau pathology, prion‐like propagation and tau‐associated neurodegeneration we generated crosses of NLRP3 deficient mice with tauP301S (PS19) transgenic mice. In this model we studied non‐seeded tau pathology and hippocampal atrophy, reminiscent characteristics of tauopathies. Tau pathology in hippocampus and cortex was significantly decreased in tau.NLRP3−/− versus tau.NLRP3+/+ mice. Importantly, tau.NLRP3−/− mice also displayed significantly decreased hippocampal atrophy, indicating a role of NLRP3 in neurodegeneration. We furthermore assessed the effect of NLRP3 deficiency on tau propagation and associated hippocampal atrophy. NLRP3 deficiency significantly decreased prion‐like seeding and propagation of tau pathology, reflected in decreased tau pathology in ipsi‐ and contralateral hippocampus and cortex in tau.NLRP3−/− following tau seeding. Most importantly, hippocampal atrophy was significantly less in tau‐seeded tau.NLRP3−/− mice at 8 months. We here demonstrate for the first time that NLRP3 activation affects tau‐associated neurodegeneration and seeded and non‐seeded tau pathology, hence affecting key molecular processes in tauopathies. Our data thereby provide key‐information in the validation of NLRP3 inflammasome as therapeutic target for AD and related tauopathies.