bluuebunny/crossref_metadata_2025 huggingface dataset:
CD28-independent Induction of T Helper Cells and Immunoglobulin Class Switches Requires Costimulation by the Heat-stable Antigen
Authors: Wu Yan , Zhou Qunmin , Zheng Pan , Liu Yang
Published: July 2002

It is well established that B7-CD28/CTLA4 interactions play an important role in the induction of T helper cells for T-dependent antibody responses. However, targeted mutation of CD28 does not significantly affect production of IgG and activation of CD4 T helper cells in response to infections by some viruses and nematode parasites. To test whether the CD28-independent induction of Ig class switches requires costimulation by the heat-stable antigen (HSA), we compared T helper cell induction and antibody response in mice deficient for either HSA, CD28, or both genes. We found that after immunization with KLH-DNP, mice deficient for both CD28 and HSA lack DNP-specific IgA and all subtypes of IgG. This deficiency corresponds to a reduced number of effector helper T cells that rapidly produce IL-2, IL-4, and IFN-γ after in vitro stimulation with carrier antigen KLH. In contrast, priming of T helper cells and Ig class switch are normal in mice deficient with either HSA or CD28 alone. IgM responses are not affected by any of these targeted mutations. These results demonstrate that CD28-independent induction of T helper cells and Ig class-switches requires costimulation by the HSA.
Inhibition of Interleukin 7 Receptor Signaling by Antigen Receptor Assembly
Authors: Smart Fiona M. , Venkitaraman Ashok R.
Published: July 2002

After the productive rearrangement of immunoglobulin (Ig) heavy chain genes, precursor (pre-)B lymphocytes undergo a limited number of cell divisions in response to interleukin (IL)-7. Here, we present evidence that this phase of IL-7–dependent expansion is constrained by an inhibitory signal initiated by antigen receptor assembly. A line of pre-B cells from normal murine bone marrow that expresses a μ heavy chain with a D-proximal VH7183.2 region divides continuously in IL-7. IL-7 responsiveness ceases upon differentiation to the μ1, κ1 stage, despite continuing expression of the IL-7 receptor (IL-7R), suggesting that antigen receptor assembly inhibits IL-7 responsiveness. This is confirmed by introduction of a rearranged λ light chain gene, which inhibits proliferative signaling through the IL-7R. Inhibition is specific to the IL-7R, because it is overcome by replacement of the IL-7R cytoplasmic domain with corresponding sequences from the closely related IL-2Rβ chain. Alteration of a single tyrosine residue, Tyr410, in the IL-7R cytoplasmic domain to phenylalanine also prevents the inhibition of proliferation after antigen receptor assembly. Thus, the loss of IL-7 responsiveness after antigen receptor assembly may be mediated through the recruitment of an inhibitory molecule to this residue. Our findings identify a novel mechanism that limits cytokine-dependent proliferation during B lymphopoiesis. This mechanism may be essential for the proper regulation of peripheral B lymphocyte numbers.
Role of 2c T Cell Receptor Residues in the Binding of Self–And Allo–Major Histocompatibility Complexes
Authors: Lee Peter U.Y. , Churchill Hywyn R.O. , Daniels Mark , Jameson Stephen C. , Kranz David M.
Published: July 2002

T cell clone 2C recognizes the alloantigen Ld and the positive selecting major histocompatibility complex (MHC), Kb. To explore the molecular basis of T cell antigen receptor (TCR) binding to different peptide/MHC (pMHC) complexes, we performed alanine scanning mutagenesis of the 2C TCR. The TCR energy maps for QL9/Ld and SIYR/Kb were remarkably similar, in that 16 of 41 Vα and Vβ alanine mutants showed reduced binding to both ligands. Several TCR residues varied in the magnitude of energy contributed to binding the two ligands, indicating that there are also unique interactions. Residues in complementarity determining region 3α showed the most notable differences in binding energetics among the ligands QL9/Ld, SIYR/Kb, and the clonotypic antibody 1B2. Various lines of evidence suggest that these differences relate to the mobility of this loop and point to the key role of conformational dynamics in pMHC recognition.
Permeant Ion-Dependent Changes in Gating of Kir2.1 Inward Rectifier Potassium Channels
Authors: Lu Tao , Wu Li , Xiao Jun , Yang Jian
Published: July 2002

We studied the effect of monovalent thallium ion (Tl+) on the gating of single Kir2.1 channels, which open and close spontaneously at a constant membrane potential. In cell-attached recordings of single-channel inward current, changing the external permeant ion from K+ to Tl+ decreases the mean open-time by ∼20-fold. Furthermore, the channel resides predominantly at a subconductance level, which results from a slow decay (τ = 2.7 ms at −100 mV) from the fully open level immediately following channel opening. Mutation of a pore-lining cysteine (C169) to valine abolishes the slow decay and subconductance level, and single-channel recordings from channels formed by tandem tetramers containing one to three C169V mutant subunits indicate that Tl+ must interact with at least three C169 residues to induce these effects. However, the C169V mutation does not alter the single-channel closing kinetics of Tl+ current. These results suggest that Tl+ ions change the conformation of the ion conduction pathway during permeation and alter gating by two distinct mechanisms. First, they interact with the thiolate groups of C169 lining the cavity to induce conformational changes of the ion passageway, and thereby produce a slow decay of single-channel current and a dominant subconductance state. Second, they interact more strongly than K+ with the main chain carbonyl oxygens lining the selectivity filter to destabilize the open state of the channel and, thus, alter the open/close kinetics of gating. In addition to altering gating, Tl+ greatly diminishes Ba2+ block. The unblocking rate of Ba2+ is increased by >22-fold when the external permeant ion is switched from K+ to Tl+ regardless of the direction of Ba2+ exit. This effect cannot be explained solely by ion–ion interactions, but is consistent with the notion that Tl+ induces conformational changes in the selectivity filter.
PLAC-24 Is a Cytoplasmic Dynein-Binding Protein That Is Recruited to Sites of Cell-Cell Contact
Authors: Karki Sher , Ligon Lee A. , DeSantis Jamison , Tokito Mariko , Holzbaur Erika L. F.
Published: July 2002

We screened for polypeptides that interact specifically with dynein and identified a novel 24-kDa protein (PLAC-24) that binds directly to dynein intermediate chain (DIC). PLAC-24 is not a dynactin subunit, and the binding of PLAC-24 to the dynein intermediate chain is independent of the association between dynein and dynactin. Immunocytochemistry using PLAC-24–specific polyclonal antibodies revealed a punctate perinuclear distribution of the polypeptide in fibroblasts and isolated epithelial cells. However, as epithelial cells in culture make contact with adjacent cells, PLAC-24 is specifically recruited to the cortex at sites of contact, where the protein colocalizes with components of the adherens junction. Disruption of the cellular cytoskeleton with latrunculin or nocodazole indicates that the localization of PLAC-24 to the cortex is dependent on intact actin filaments but not on microtubules. Overexpression of β-catenin also leads to a loss of PLAC-24 from sites of cell-cell contact. On the basis of these data and the recent observation that cytoplasmic dynein is also localized to sites of cell-cell contact in epithelial cells, we propose that PLAC-24 is part of a multiprotein complex localized to sites of intercellular contact that may function to tether microtubule plus ends to the actin-rich cellular cortex.
Brightening Country Lives: Selling Electrical Goods in the Japanese Countryside, 1950–1970
Authors: Partner Simon
Published: July 2002

In the aftermath of World War II, Japanese companies looked to the United States as a model of middle-class, consumer-driven prosperity. Although living conditions in Japan were very different from those in the United States, Japanese companies imported product technologies and management techniques that helped them realize their vision of a mass consumer society. For electrical goods companies, the countryside represented a special challenge, as conservative values and traditional family structures hindered sales. In time, however, electrical goods companies were able to overcome these obstacles, and in the process they became major players in the transformation of peasants into consumers.
The Coulomb Green’s function in two dimensions
Authors: Dittrich Walter
Published: July 2002

We consider the two-dimensional nonrelativistic Coulomb problem with the aid of the momentum space construction of the associated Green’s function. Our presentation has precursors in three dimensions. It is mainly Schwinger’s approach which we advocate and project onto two dimensions.
Small-slope scattering from rough elastic ocean floors: General theory and computational algorithm
Authors: Gragg Robert F. , Wurmser Daniel , Gauss Roger C.
Published: July 2002

In this article acoustic scattering by a random rough interface that separates a fluid incident medium from an underlying uniform scattering medium, either fluid or elastic solid, in cases for which the Bragg scale lies within the power-law tail of the roughness spectrum is dealt with. The physical foundation is an inherently reciprocity-preserving, local small-slope theory. A fully bistatic formulation is developed for the scattering strength, together with a robust numerical implementation that allows a wide range of spectral exponent values. The practical result for ocean acoustics is a significantly improved description of the interface component of sea floor scattering. Calculations are presented to demonstrate the advantage of this approach over perturbation theory, and to illustrate its dependence on frequency and environmental parameters as well as its operation in bistatic geometries.
Efficient estimation of the probability that a source track is examined in a matched-field processing tracking algorithm
Authors: Zala Cedric A. , Ozard John M. , Wilmut Michael J.
Published: July 2002

Tracking techniques may be used to reduce the ambiguity of an acoustic source’s position in matched-field processing, particularly for low signal-to-noise ratios. An efficient tracking algorithm was recently described, in which the performance would be comparable to that of an exhaustive tracker; that is, the probability that the source track is examined is close to unity for cases of interest. The current paper describes an efficient technique to estimate the probability that the source track is examined. The procedure involves the use of noise-only data to define statistical thresholds for the strongest peaks in the ambiguity surface. Once these thresholds are defined, the required probabilities may be estimated by evaluating the ambiguity function for signal-plus-noise data within a small region surrounding the known source location, and identifying any peaks exceeding the thresholds. Results of simulations obtained for a slanted array indicate that this approach provides an effective way to estimate the probability that the source track is examined.
An adaptive noise canceller for hearing aids using two nearby microphones
Authors: Vanden Berghe Jeff , Wouters Jan
Published: July 2002

An adaptive noise cancellation scheme based on two-stage adaptive filtering as proposed by Van Compernolle [Proceedings of the IEEE International Conference on Acoustics, Speech and Signal Processing (IEEE, New York, 1990)] was tested for two identical directional microphones mounted in an endfire configuration within a single behind-the-ear (BTE) hearing aid. Speech intelligibility tests were carried out with two normal hearing subjects and three hearing aid users with moderate hearing losses, in a realistic test environment using open set words and sentences. A significant improvement, on average more than 5 dB, of speech reception threshold (SRT) in background noise was obtained.
Anderson (1950) revisited
Authors: Feuillade C. , Clay C. S.
Published: July 2002

The Anderson fluid sphere scattering model [J. Acoust. Soc. Am. 22, 426–431 (1950)] is reexamined to clarify three issues which have been the source of misunderstanding among underwater acousticians. First, the accuracy of the Morse large range approximation for the spherical Hankel functions is investigated. It is shown that the minimum range for use of the approximation is strongly mode number dependent, and should be carefully evaluated in short range and/or high frequency applications. Second, the precise characterization of the forward scatter region is studied. When the scattered field and the incident plane wave are combined, it is shown that little advantage is obtained in detection and localization applications by using forward scattering, rather than backscattering. Third, the translational response, or “rebound,” of the sphere under the action of the incident field is examined. By demonstrating that Anderson’s theory is a limiting case of Faran’s scattering model [J. Acoust. Soc. Am. 23, 405–418 (1951)] for an elastic sphere, which contains the rebound response, it is shown that the response is completely explainable within Anderson’s theory, and is consistent with a description which uses a normal mode expansion around a fixed origin.
Proportional frequency compression of speech for listeners with sensorineural hearing loss
Authors: Turner Christopher W. , Hurtig Richard R.
Published: July 2002

This study examined proportional frequency compression as a strategy for improving speech recognition in listeners with high-frequency sensorineural hearing loss. This method of frequency compression preserved the ratios between the frequencies of the components of natural speech, as well as the temporal envelope of the unprocessed speech stimuli. Nonsense syllables spoken by a female and a male talker were used as the speech materials. Both frequency-compressed speech and the control condition of unprocessed speech were presented with high-pass amplification. For the materials spoken by the female talker, significant increases in speech recognition were observed in slightly less than one-half of the listeners with hearing impairment. For the male-talker materials, one-fifth of the hearing-impaired listeners showed significant recognition improvements. The increases in speech recognition due solely to frequency compression were generally smaller than those solely due to high-pass amplification. The results indicate that while high-pass amplification is still the most effective approach for improving speech recognition of listeners with high-frequency hearing loss, proportional frequency compression can offer significant improvements in addition to those provided by amplification for some patients.
Comparison between the dispersion curves calculated in complex frequency and the minima of the reflection coefficients for an embedded layer
Authors: Bernard A. , Deschamps M. , Lowe M. J. S.
Published: July 2002

Analytical solutions of Lamb functions for symmetric and antisymmetric elastodynamic modes propagating within a solid layer embedded in an infinite medium are presented. Alternative theoretical analyses of such modes are performed, first in terms of the usual approach of harmonic heterogeneous plane waves (real frequency and complex slowness) and then in terms of transient homogeneous plane waves (complex frequency and real slowness). An example structure of a 0.1-mm-thick “alpha case” (an oxygen-rich phase of titanium that is relatively stiff) plate embedded in titanium is used for the study. A large difference between the usual dispersion curves calculated in real frequency and complex slowness and those calculated in complex frequency and real slowness is shown. Thus the choice between a spatial and a temporal parameter to describe the imaginary part of the guided waves is shown to be significant. The minima and the zeros of the longitudinal and shear plane-wave reflection coefficients are calculated and are compared with the dispersion curves. It is found that they do not match with the dispersion curves for complex slowness, but they do agree quite well with the dispersion curves for complex frequency. This implies that the complex frequency approach is better suited for the comparison of the modal properties with near-field reflection measurements.
Anisotropy of ultrasonic propagation and scattering properties in fresh rat skeletal muscle in vitro
Authors: Topp Karen A. , O’Brien William D.
Published: July 2002

The anisotropy of frequency-dependent backscatter coefficient, attenuation, and speed of sound is assessed in fresh rat skeletal muscle within 5 h post-mortem. Excised rat semimembranosus and soleus muscles are measured in 37 °C Tyrode solution, with the muscle fibers at 90° and 45° orientations to the incident sound beam. Reflected and through transmission signals from either a 6- or 10-MHz focused transducer give frequency dependent information in the 4–14 MHz range. The attenuation coefficient in each muscle is consistently a factor of 2.0±0.4 lower for propagation perpendicular to the fibers than at 45°, whereas speed of sound shows a much milder anisotropy, and is slightly faster for the 90° orientation. The largest anisotropy is seen in the backscatter coefficient, most notably in the semimembranosus where the magnitude at 90° is over an order of magnitude greater than at 45°, with the frequency dependence in both cases giving a power law between 1.5 and 2.0.
Hypothesis on a Certain Flow Instability in Polymer Melts
Authors: Huseby T. W.
Published: July 2002

Application is made of Pao's theory for viscoelastic flow together with measurements of the relaxation spectrum to analyze the flow behavior of polymer melts. One result for linear polyethylene is that over a limited range of shear rate, the shear stress becomes a many-valued function of shear rate. This behavior arises as a natural consequence of the viscoelastic nature of polymers and appears to unify many previous experimental observations of the behavior of polymer melts at high shear rates. The theory predicts an instability in the flow curve of linear polyethylene. It predicts that this discontinuity occurs at different values depending on whether the shear stress is increasing or decreasing. The recoverable strain is predicted to pass through a maximum and the velocity of a material particle in the unstable region can have a number of values at different instants in time. One interpretation of this would be that the flow can occur as a “stick-slip” process. The effect of hydrostatic pressure on the flow curve is also discussed. All of the results of this analysis have been observed experimentally by others.
Dynamic Mechanical Properties of Cross-Linked Rubbers. IV. Dicumyl Peroxide Vulcanizates of Styrene-Butadiene Rubber
Authors: Mancke Ralph G. , Ferry John D.
Published: July 2002

The viscoelastic properties of three samples of a random styrene-butadiene co-polymer with 23.5 wt-% styrene, cross-linked by dicumyl peroxide to different extents, have been studied by dynamic shear and shear creep measurements, and the unvulcanized precursor has been studied in creep. The frequency and temperature ranges were 0.2 to 3600 cps and −30 to 55°C. The creep data were converted to the corresponding dynamic viscoelastic functions at very low frequencies. All data were reduced to T0=298°K by shift factors calculated from the equation log aT=−4.57(T−T0)/(113.6+T−T0). By fitting the creep to a modification of the empirical equation of Thirion and Chasset, values of the equilibrium compliance and relaxation parameters were obtained in good agreement with results of those authors from stress relaxation in extension. All the viscoelastic functions displayed two principal regions of frequency dependence as found for other rubberlike polymers. The high-frequency dispersion, near 105 on the radian frequency scale, is affected very little by increasing cross-linking and corresponds to a compliance increment of about 1.1×10−7 cm2/dyne for all samples. It is attributed to the entanglement network originally present before vulcanization. The low-frequency dispersion, at 1 radian/sec and below, corresponds to a compliance increment which increases rapidly with decreasing chemical cross-linking, while the dispersion broadens and shifts to lower frequencies.
Transient Response of an Elastomer to Large Shearing and Stretching Deformations
Authors: Middleman Stanley
Published: July 2002

Data are presented, using undiluted polyisobutylene, for the transient response to the sudden imposition of simple shearing and constant speed elongation. A constitutive equation due to Bogue describes the basic features of the observed responses.
Shear Rate Dependent Relaxation Spectrum: Conversion from Dynamic Viscosity to Steady Flow Viscosity for Polyethylene Melts
Authors: Shida Mitsuzo , Shroff Ramesh N.
Published: July 2002

The steady flow viscosity η and the dynamic viscosity η′ of several linear polyethylene melts (190°C) were measured using the Weissenberg rheogoniometer and the Instron rheometer. In correlating the two viscosities, the use of Graessley's theory of viscosity in steady shearing flow in combination with the box distribution of relaxation times as suggested by Maruyama et al. has been critically examined. The new approach discussed in this paper uses Graessley's functions h(θ) and g(θ) in conjunction with the relaxation spectrum H(τ) derived from linear viscoelastic data using an iterative method. The required relation is η(γ̇)=∫H(τ)h(θ)g(θ)3/2τd ln τ, θ=γ̇τ/2; where γ̇ is the shear rate and τ is the relaxation time. Here g(θ)=(2/π) [cot−1 θ+θ/(1+θ2)] and k(θ)=(2/π) [cot−1 θ+θ (1−θ2)/(1+θ2)2]. A good agreement was obtained in all cases without involving any coordinate shift. The approach illustrated in this article enabled us to estimate quantitatively the effect of shear rate on the relaxation spectrum and also to estimate fractional contribution to the viscosity at a given relaxation time and shear rate.
Isothermal Spinning of Molten Polyethylenes
Authors: Spearot J. A. , Metzner A. B.
Published: July 2002

The behavior of a series of molten polyethylenes has been studied in the extensional flow field of a fiber spinning apparatus. Separate rheogoniometric measurements have been made of the physical properties in shearing flows and the experimental results of the fiber spinning experiment are compared with the predictions obtainable using constitutive relationships in which all of the parameters are determinable from appropriate shearing experiments. Stress levels more than one order of magnitude greater than those predicted on the assumption of isothermal Newtonian behavior were observed.
Instability of Jets of Non-Newtonian Fluids
Authors: Gordon Marvin , Yerushalmi Joseph , Shinnar Reuel
Published: July 2002

The instability of jets of some non-Newtonian fluids under the influence of externally controlled disturbances was studied. Dispersion curves were generated over a range of frequencies. Jets of a 0.1% solution of Carbopol in water, a viscoinelastic fluid, showed a breakup pattern similar to that of jets of water. The dispersion curve matched a viscosity intermediate to the zero shear viscosity of the solution and the viscosity that corresponds to the average shear rate in the tube. Subject to external disturbances, jets of Separan solutions showed a remarkably ordered and regular pattern. On jets of 0.1% Separan, sinusoidal wave formation was absent and a ligament-droplet configuration formed from the outset. On the less elastic 0.05% Separan jets, there is an initial region in which sinusoidal waves grow exponentially; the growth is later arrested and a ligament-droplet configuration results. In the initial region the growth rates are about equal to the growth rates that a jet of a Newtonian fluid of the same zero shear viscosity would develop. The ligaments that form on jets of Separan are shown to undergo a stretching motion accounting in part for their unusual stability.
Elongational and Shear Viscosities of a Bead-Filled Thermoplastic
Authors: Nazem Faramarz , Hill Christopher T.
Published: July 2002

Elongational and shear viscosities of bead-filled styrene acrylonitrile composites were measured in the rubbery flow region at very low strain rates. Composites contained 9–37% spherical glass beads by volume. Within experimental error, elongational viscosity was found to be constant and equal to three times shear viscosity at very low strain rates for the composites containing less than 20 vol % glass beads. The experimental data were used to evaluate a number of the classical theories for the viscosity of suspensions. In general, the theories were more appropriate for the elongational than for the shear data. Both elongational and shear viscosities were discovered to have the same dependence on the filler concentration up to 20 vol % glass beads. Dewetting is very noticeable in high strain tensile testing for all nonzero filler concentrations. In the data presented here, simultaneous measurements of longitudinal extension and lateral contraction established that the samples did not dewet during the viscosity measurements.
Dynamic Response of Viscoelastic Solids in Liquid Media
Authors: Maclean Donald L. , Murayama Takayuki
Published: July 2002

A theoretical and experimental investigation of the dynamic mechanical properties of polymeric films in liquid media has been conducted. In an analytical development the effect of a viscous medium surrounding the specimen on the dynamic mechanical measurement is determined by calculating the viscous drag on the specimen which is subjected to a sinusoidal oscillation; this result is incorporated with the dynamic modulus analysis. The resulting expressions are demonstrated to predict the effective dynamic mechanical properties of films in liquid media by knowing the dimensions, viscosity, and density of the liquid and the frequency of oscillation. In order to separate the viscous drag from any polymer-solvent interactions, a series of experimental studies using the Vibron instrument was conducted to measure the effective dynamic mechanical properties of films in a variety of noninteracting liquid media and dry conditions. The resultant dry measurements were used along with the theory to show the effect of viscous drag on the dynamic mechanical properties of a film in a liquid medium.
Rotational viscometry under presence of apparent wall slip
Authors: Wein O. , Tovchigrechko V. V.
Published: July 2002

A new way is suggested for treatment of the viscometric data, obtained in a rotational viscometer using several configurations of coaxial cylinders with different gap widths. Liquids are assumed to display both a general shear-thinning behavior and an apparent slip at solid boundaries. The body of primary data is at first smoothed using a conventional least-squares fitting. The subsequent procedure, called local filtering, gives a nonparametric representation of the both material functions γ̇=γ̇(τ) and u=u(τ). Several data sets for aqueous polymeric solutions with high content of electrolytes are treated to demonstrate the typical problems encountered in analyzing apparent wall-slip effects. When compared with the data found in literature, the slip velocities obtained are slightly higher, probably due to an enhanced coagulation caused by the presence of electrolytes.
Association of State-Level Firearm-Related Deaths With Firearm Laws in Neighboring States
Authors: Liu Ye , Siegel Michael , Sen Bisakha
Published: November 2022

Importance

Firearms are easily transported over state borders; hence permissive firearm laws in one state may have an interstate association with firearm-related deaths in nearby states.

Objectives

To examine whether certain firearm laws have an interstate association with firearm-related deaths in nearby states.

Design, Setting, and Participants

This cross-sectional observational study used data on state firearm-related deaths in the 48 contiguous states of the US between January 1, 2000, and December 31, 2019. A spatial autoregressive model with fixed effects for state and year was used to evaluate within-state, interstate, and overall associations between firearm laws and firearm-related deaths. Analyses were performed during January 2022.

Exposures

The following 9 types of laws were evaluated: universal background checks for all firearms purchase, background checks for handgun sales at gun shows, license requirement to purchase all firearms, state dealer license requirement for handgun sales, requirement of retaining records of handgun sales, ban on purchasing a handgun on behalf of another, prohibition of firearm possession by persons who committed violent misdemeanors, required relinquishment of firearms for persons becoming prohibited from possessing them, and discretion in granting a concealed carry permit.

Main Outcomes and Measures

State-level total firearm-related death rates, suicide rates, and homicide rates.

Results

In sum, the study period included 662 883 firearm-related deaths of all intents. License requirement for firearm purchase had a within-state association (effect size, −1.79 [95% CI, −2.73 to −0.84]), interstate association (effect size, −10.60 [95% CI, −17.63 to −3.56]), and overall association (effect size, −12.38 [95% CI, −19.93 to −4.83]) per 100 000 population decrease in total firearm-related deaths. This law also had within-state association (effect size, −1.26 [95% CI, −1.72 to −0.80]), interstate association (effect size, −9.01 [95% CI, −15.00 to −3.02]), and overall association (effect size, −10.27 [95% CI, −16.53 to −4.01]) per 100 000 population decrease in firearm-related homicide.

Conclusions and Relevance

The findings of this pooled cross-sectional analysis suggest that certain firearm laws in one state were associated with other states’ firearm-related deaths. Synergic legislative action in adjacent states, federal firearm legislation, and measures that reduce migration of firearms across state borders should be part of the overarching strategy to prevent firearm-related deaths.
Crumpling Carbon‐Pillared Atomic‐Thin Dichalcogenides and CNTs into Elastic Balls as Superior Anodes for Sodium/Potassium‐Ion Batteries
Authors: Zhu Xinxin , Xia Fanjie , Liu Dan , Xiang Xinyuan , Wu Jinsong , Lei Jiaheng , Li Junsheng , Qu Deyu , Liu Jinping
Published: November 2022

With abundant electroactive sites and rapid ion diffusion paths, ultrathin dichalcogenides such as MoS2 demonstrate enormous potential as anodes for sodium/potassium‐ion batteries (SIBs/PIBs). However, ultrahigh‐aspect‐ratio nanosheets are very easy to aggregate and re‐stack, drastically weakening their intrinsic merits. Here a sustainable dichalcogenide anode is designed via crumpling carbon‐pillared atomic‐thin MoS2 nanosheets with CNTs into an elastic ball structure (C‐p‐MoS2/CNTs). In this architecture, the glucose‐derived carbon pillars atomic‐thin MoS2 nanosheets and broadens interlayer spacing, ensuring fast Na+/K+ diffusion; CNTs act as 3D scaffolds to impede re‐stacking of MoS2 while providing high‐speed pathways for electrons; the integration of flexible atomic‐thin sheets and high‐toughness CNTs further endows the balls with great elasticity to release the cycling stress. Consequently, the C‐p‐MoS2/CNTs material delivers high reversible capacities, outstanding cycling stability, and superior rate performance as anodes for both SIBs and PIBs. Pairing with Na3V2(PO4)2F3 cathode, the sodium‐ion coin‐cell could operate at a rate up to 50 C at high mass loading of 9.4 mg cm−2 and manifest ultrastable cycling stability at 40 C over 600 cycles. Impressively, the assembled pouch cell can be cycled stably with a high energy density of 188 Wh kg−1. This study is anticipated to provide inspiration for designing innovative metal dichalcogenides as battery anodes.
Surface Chemistry Determined Electrochemical Sensing Performance of Red Phosphorus and Single Walled Carbon Nanotube Composites
Authors: Liu Lingbo , Lei Ling , Zeng Keni , Wu Kangbing , Yang Nianjun
Published: November 2022

Red phosphorus (RP) is a promising electrochemical sensing material owing to its abundant surface groups and reactive sites. In this study, a sodium dodecyl sulfate‐assisted phosphorus‐amine approach is employed to tune surface chemistry of RP nanoparticles. During the transition of the polyphosphorus‐amine anion to RP, the cleavage of POP bond and the formation of POC bond are monitored by in situ attenuated total reflection surface‐enhanced infrared absorption spectroscopy. The formed POC bonds that are originated from the PO reactive sites are theoretically revealed with the density functional theory calculations, charge density difference, and X‐ray photoelectron spectroscopy. The energies of optimized aromatic and aliphatic POC bonds are −2.51 and −2.65 eV, respectively. To explore electrochemical sensing applications, RP nanoparticles are in situ grown on single‐walled carbon nanotube (SWCNT). Such a stable RP/SWCNT suspension is applied to fabricate the RP/SWCNT integrated arrays via a template‐filtration method. Such an array is efficient for sensitive and selective monitoring of p‐phenylenediamine on hair dyes. This study provides insights into surface chemistry of RP, its roles in electrochemical sensing applications, and an approach to produce high‐performance RP sensors at large scales.
Avalanche Coalescence of Liquid Metal Particles for Uniform Flexible and Stretchable Electrodes
Authors: Park Kwangseok , Pyeon Jeongsu , Jeong Seung Hee , Yoon Yong‐Jin , Kim Hyoungsoo
Published: November 2022

Self‐sinterable gallium‐based liquid metal (LM) ink for a handy drop‐casting coating method is developed. The fabricated LM electrode is coffee‐ring‐free and bilayer‐free, which guarantees high electrical conductivity, wettability, flexibility, and stretchability. The ink consists of Galinstan, ethanol‐water mixture, hydrochloric acid, and polyvinylpyrrolidone. The binary mixture provides excellent wetting conditions and suppresses a coffee‐ring stain from Marangoni mixing. The acid removes an oxide layer on the LM interface. The colloidal interaction forces by self‐assembled polyvinylpyrrolidone induce avalanche coalescences of the particles at the end of evaporation, which produces a thin and uniform dried conductive layer. The acid and polymer provide a bilayer‐free structure and electrification without any post sintering. The drop‐casted self‐transformed LM electrode showed excellent electrical resistance of O (0.1–1 Ω) on folding and stretching conditions. It is believed that this method can serve as flexible and stretchable electrodes, on various substances for soft robots and wearable devices, without any complicated post‐process.
Triphenylcarbenium Tetrafluoroborate‐Catalyzed 1,6‐Addition of 1‐Aminobenzotriazole to p‐Quinone Methides: Synthesis of Diarylmethylamines
Authors: Song Ran , Zhuo Caiqi , Si Wen , Wu Xiaoying , Guan Tianyi , Yang Daoshan , Lv Jian
Published: November 2022

A metal‐free synthesis of diarylmethylamines via triphenylcarbenium tetrafluoroborate‐catalyzed 1,6‐addition of 1‐aminobenzotriazole to p‐quinone methides (p‐QMs) was developped. Under mild condition, diarylmethylamines could be obtained in moderate to good yields (up to 84%) by simple filtration, showing essentially unchanged activity after 6 reuses.

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Birth defects associated with paternal firefighting in the National Birth Defects Prevention Study
Authors: Siegel Miriam R. , Rocheleau Carissa M. , Hollerbach Brittany S. , Omari Amel , Jahnke Sara A. , Almli Lynn M. , Olshan Andrew F. ,   National Birth Defects Prevention Study
Published: November 2022

Background

Few studies have evaluated birth defects among children of firefighters. We investigated associations between birth defects and paternal work as a firefighter compared to work in non‐firefighting and police officer occupations.

Methods

We analyzed 1997–2011 data from the multi‐site case‐control National Birth Defects Prevention Study. Cases included fetuses or infants with major structural birth defects and controls included a random sample of live‐born infants without major birth defects. Mothers of infants self‐reported information about parents' occupations held during pregnancy. We investigated associations between paternal firefighting and birth defect groups using logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Referent groups included families reporting fathers working non‐firefighting and police officer jobs.

Results

Occupational groups included 227 firefighters, 36,285 non‐firefighters, and 433 police officers. Twenty‐nine birth defects were analyzed. In adjusted analyses, fathers of children with total anomalous pulmonary venous return (TAPVR; OR = 3.1; 95% CI = 1.1–8.7), cleft palate (OR = 1.8; 95% CI = 1.0–3.3), cleft lip (OR = 2.2; 95% CI = 1.2–4.2), and transverse limb deficiency (OR = 2.2; 95% CI = 1.1–4.7) were more likely than fathers of controls to be firefighters, versus non‐firefighters. In police‐referent analyses, fathers of children with cleft palate were 2.4 times more likely to be firefighters than fathers of controls (95% CI = 1.1–5.4).

Conclusions

Paternal firefighting may be associated with an elevated risk of birth defects in offspring. Additional studies are warranted to replicate these findings. Further research may contribute to a greater understanding of the reproductive health of firefighters and their families for guiding workplace practices.
Bioinspired Gradient Stretchable Aerogels for Ultrabroad‐Range‐Response Pressure‐Sensitive Wearable Electronics and High‐Efficient Separators
Authors: Zhang Xiaoyu , Hu Zhenyu , Sun Qi , Liang Xing , Gu Puzhong , Huang Jia , Zu Guoqing
Published: November 2022

Broad‐range‐response pressure‐sensitive wearable electronics are urgently needed but their preparation remains a challenge. Herein, we report unprecedented bioinspired wearable electronics based on stretchable and superelastic reduced graphene oxide/polyurethane nanocomposite aerogels with gradient porous structures by a sol‐gel/hot pressing/freeze casting/ambient pressure drying strategy. The gradient structure with a hot‐pressed layer promotes strain transfer and resistance variation under high pressures, leading to an ultrabroad detection range of 1 Pa–12.6 MPa, one of the broadest ranges ever reported. They can withstand 10 000 compression cycles under 1 MPa, which can't be achieved by traditional flexible pressure sensors. They can be applied for broad‐range‐response electronic skins and monitoring various physical signals/motions and ultrahigh pressures of automobile tires. Moreover, the gradient aerogels can be used as high‐efficient gradient separators for water purification.
Bayesian Self‐Optimization for Telescoped Continuous Flow Synthesis
Authors: Clayton Adam D. , Pyzer‐Knapp Edward O. , Purdie Mark , Jones Martin F. , Barthelme Alexandre , Pavey John , Kapur Nikil , Chamberlain Thomas W. , Blacker A. John , Bourne Richard A.
Published: November 2022

The optimization of multistep chemical syntheses is critical for the rapid development of new pharmaceuticals. However, concatenating individually optimized reactions can lead to inefficient multistep syntheses, owing to chemical interdependencies between the steps. Herein, we develop an automated continuous flow platform for the simultaneous optimization of telescoped reactions. Our approach is applied to a Heck cyclization‐deprotection reaction sequence, used in the synthesis of a precursor for 1‐methyltetrahydroisoquinoline C5 functionalization. A simple method for multipoint sampling with a single online HPLC instrument was designed, enabling accurate quantification of each reaction, and an in‐depth understanding of the reaction pathways. Notably, integration of Bayesian optimization techniques identified an 81 % overall yield in just 14 h, and revealed a favorable competing pathway for formation of the desired product.
Superchaotropic Nano‐ion Binding as a Gelation Motif in Cellulose Ether Solutions
Authors: Hohenschutz Max , Bauduin Pierre , Lopez Carlos G. , Förster Beate , Richtering Walter
Published: November 2022

Nanometer‐sized anions (nano‐ions) like polyoxometalates and boron clusters exhibit so‐called superchaotropic behavior, which describes their strong binding to hydrated non‐ionic matter in water. We show here that nano‐ions, at millimolar concentrations, dramatically enhance the viscosity and induce gelation of aqueous solutions of non‐ionic cellulose ethers (CEs), a class of widely utilized polymers known for their thickening and gel‐forming ability. These phenomena arise from an interplay of attractive forces and repulsive electrostatic forces between CE‐chains upon nano‐ion binding. The attractive forces manifest themselves as aggregation of CE‐chains into a physically crosslinked polymer network (gel). In turn, the electrostatic repulsions hamper the viscosity increase and gelation. Superchaotropic nano‐ion binding emerges as a novel and general physical crosslinking motif for CE‐solutions and exceeds by far the conventional thickening effects of classical salts and ionic surfactants.
Circularly Polarized Light Probes Excited‐State Delocalization in Rectangular Ladder‐type Pentaphenyl Helices
Authors: Ammenhäuser Robin , Klein Patrick , Schmid Eva , Streicher Sabrina , Vogelsang Jan , Lehmann Christian W. , Lupton John M. , Meskers Stefan C. J. , Scherf Ullrich
Published: November 2022

Ladder‐type pentaphenyl chromophores have a rigid, planar π‐system and show bright fluorescence featuring pronounced vibrational structure. Such moieties are ideal for studying interchromophoric interactions and delocalization of electronic excitations. We report the synthesis of helical polymers with a rigid square structure based on spiro‐linked ladder‐type pentaphenyl units. The variation of circular dichroism with increasing chain length provides direct evidence for delocalization of electronic excitations over at least 10 monomeric units. The change in the degree of circular polarization of the fluorescence across the vibronic side bands shows that vibrational motion can localize the excitation dynamically to almost one single unit through breakdown of the Born‐Oppenheimer approximation. The dynamic conversion between delocalized and localized excited states provides a new paradigm for interpreting circular dichroism in helical polymers such as proteins and polynucleic acids.
An Amorphous n‐Type Conjugated Polymer with an Ultra‐Rigid Planar Backbone
Authors: Cao Xu , Li Hongxiang , Hu Junli , Tian Hongkun , Han Yanchun , Meng Bin , Liu Jun , Wang Lixiang
Published: November 2022

High charge carrier mobility polymer semiconductors are always semi‐crystalline. Amorphous conjugated polymers represent another kind of polymer semiconductors with different charge transporting mechanism. Here we report the first near‐amorphous n‐type conjugated polymer with decent electron mobility, which features a remarkably rigid, straight and planar polymer backbone. The molecular design strategy is to copolymerize two fused‐ring building blocks which are both electron‐accepting, centrosymmetrical and planar. The polymer is the alternating copolymer of double B←N bridged bipyridine (BNBP) unit and benzobisthiazole (BBTz) unit. It shows a decent electron mobility of 0.34 cm2 V−1 s−1 in organic field‐effect transistors. The excellent electron transporting property of the polymer is possibly due to the ultrahigh backbone stiffness, small π‐π stacking distance, and high molecular weight.
Diboron(4)‐Catalyzed Remote [3+2] Cycloaddition of Cyclopropanes via Dearomative/Rearomative Radical Transmission through Pyridine
Authors: Xu Ming , Wang Zhijun , Sun Zhaohui , Ouyang Yizhao , Ding Zhengwei , Yu Tao , Xu Liang , Li Pengfei
Published: November 2022

Ring structures such as pyridine, cyclopentane or their combinations are important motifs in bioactive molecules. In contrast to previous cycloaddition reactions that necessitated a directly bonded initiating functional group, this work demonstrated a novel through‐(hetero)arene radical transmission concept for selective activation of a remote bond. An efficient, metal‐free and atom‐economical [3+2] cycloaddition between 4‐pyridinyl cyclopropanes and alkenes or alkynes has been developed for modular synthesis of pyridine‐substituted cyclopentanes, cyclopentenes and bicyclo[2.1.1]hexanes that are difficult to access using known methods. This complexity‐building reaction was catalyzed by a very simple and inexpensive diboron(4) compound and took place via dearomative/rearomative processes. The substrate scope was broad and more than 100 new compounds were prepared in generally high yields. Mechanistic experiments and density function theory (DFT) investigation supported a radical relay catalytic cycle involving alkylidene dihydropyridine radical intermediates and boronyl radical transfer.
Enantioselective Hydrosilylation of β,β‐Disubstituted Enamides to Construct α‐Aminosilanes with Vicinal Stereocenters
Authors: Zhang Wen‐Wen , Li Bi‐Jie
Published: November 2022

Despite the advances in the area of catalytic alkene hydrosilylation, the enantioselective hydrosilylation of alkenes bearing a heteroatom substituent is scarce. Here we report a rhodium‐catalyzed hydrosilylation of β,β‐disubstituted enamides to directly afford valuable α‐aminosilanes in a highly regio‐, diastereo‐, and enantioselective manner. Stereodivergent synthesis could be achieved by regulating substrate geometry and ligand configuration to generate all the possible stereoisomers in high enantio‐purity.
Conformational Control of Organocatalyst in Strongly Brønsted‐Acidic Metal‐Organic Frameworks for Enantioselective Catalysis
Authors: Jiang Hong , Zhao Xiangxiang , Zhang Wenqiang , Liu Yan , Li Haiyang , Cui Yong
Published: November 2022

Chiral imidodiphosphates (IDPs) have emerged as strong Brønsted acid catalysts for many enantioselective processes. However, the dynamic transformation between O,O‐syn and O,O‐anti conformers typically results in low enantioselectivity. Here we demonstrate that topologies of metal‐organic frameworks (MOFs) can be exploited to control IDP conformations and local chiral microenvironments for enantioselective catalysis. Two porous Dy‐MOFs with different topologies are obtained from an enantiopure 1,1′‐biphenol IDP‐based tetracarboxylate ligand. While the ligand adopts a 4‐ or 3‐connected (c) binding mode, all IDPs are rigidified to get only a single O,O‐syn conformation and display greatly enhanced Brønsted acidity relative to the free IDP. The MOF with the 4‐c IDP that has a relatively less compact shape than the 3‐c IDP can be an efficient and recyclable heterogeneous Brønsted acid catalysing the challenging asymmetric O,O‐acetalization reaction with up to 96 % enantiomeric excess.
Catalytic, Regioselective 1,4‐Fluorodifunctionalization of Dienes
Authors: Yu You‐Jie , Schäfer Michael , Daniliuc Constantin G. , Gilmour Ryan
Published: November 2022

A catalysis‐based regioselective 1,4‐fluorofunctionalization of trifluoromethyl substituted 1,3‐dienes has been developed to access compact, highly functionalized products. The process allows E,Z‐mixed dienes to be processed to a single E‐alkene isomer, and leverages an inexpensive and operationally convenient I(I)/I(III) catalysis platform. The first example of catalytic 1,4‐difluorination is disclosed and subsequently evolved to enable 1,4‐hetero‐difunctionalization, which allows δ‐fluoro‐alcohol and amine derivatives to be forged in a single operation. The protocol is compatible with a variety of nucleophiles including fluoride, nitriles, carboxylic acids, alcohols and even water thereby allowing highly functionalized products, with a stereocenter bearing both C(sp3)−F and C(sp3)−CF3 groups, to be generated rapidly. Scalability (up to 3 mmol), and facile post‐reaction modifications are demonstrated to underscore the utility of the method in expanding organofluorine chemical space.