bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on the Puncture Resistance of Rubber Materials Used in Protective Clothing
Authors: Thang Nguyen C , Vu-Khanh T , Lara J
Published: March 2005

The aim of this work is to investigate the intrinsic parameters that control the puncture resistance of materials used in protective clothing. The effect of various probe geometries and sample holder sizes on puncture tests results were investigated. Medical needles of different diameters and tip angles were also used as puncture probes. Various available commercial rubbers used in protective gloves were characterized. The findings of this study will be useful for recommendations for standard test method protocols to characterize the puncture resistance of protective clothing materials. When cylindrical probes with flat and rounded tip geometries are used, material puncture occurs when the strain reaches one material failure value independent of tip geometry. The failure strain is also independent of sample thickness, probe tip diameter, and the sample holder size. The results demonstrated that the tip angle of conical probes has a dramatic effect on puncture test results. The material puncture resistance obtained with conical probes with different tip angles having a tip diameter d1 and a rod diameter d2 can be interpolated from the corresponding values obtained with cylindrical probes having the same d1 and d2 diameters. On the other hand, cylindrical probes provide a more straightforward characterization of puncture and also eliminate the complex effect of conical probe-tip geometry. Test results with medical needles showed that the puncturing mechanism is different from that of conical and cylindrical probes. Puncture by medical needles involves cutting and fracture energy, whereas puncture by conical and cylindrical probes relates to failure strain.
Effect of Adjuvant on the Efficacy of Glyphosate Applied at Different Times of Day
Authors: Young BG , Young JM
Published: March 2005

Glyphosate was applied alone and with either ammonium sulfate (AMS) or RUSA 703 (a premix of hydroxypropyl guar and AMS). Herbicide treatments were applied at 3-h intervals starting at 6:00 am and ending at 9:00 pm. The efficacy of glyphosate was dependent on the application time of day for all weed species tested, except for common waterhemp in the greenhouse. In general, applications at 6:00 am and 9:00 pm resulted in the least control of all weed species. The efficacy of glyphosate was often improved with the addition of AMS when glyphosate was applied at a suboptimal time of day. RUSA 703 did not result in any benefit in glyphosate efficacy beyond AMS. The addition of RUSA 703 to glyphosate improved the efficacy of glyphosate as often as AMS in greenhouse studies, but not in field studies.
Infrared Analysis of Respirable Coal Mine Dust for Quartz: Thirty-Five Years
Authors: Ainsworth SM
Published: March 2005

The Mine Safety and Health Administration (MSHA) analyzes respirable coal mine dust samples for quartz content using infrared spectrometry. Samples are low-temperature ashed in an oxygen plasma, suspended in isopropanol, and redeposited onto a vinyl/acrylic copolymer filter for analysis using a Fourier transform infrared spectrometer. The on-filter infrared method was developed by the United States Bureau of Mines and collaboratively tested by Stanford Research Institute (SRI) under contract to the National Institute for Occupational Safety and Health and the Bureau of Mines. The results of the collaborative study were published in 1983. Although much work has been performed since then to improve the precision of the method, details of those improvements have not always been published. Standard methods often do not discuss analytical theory and the preliminary steps necessary to achieve precise results. This paper gives a brief background of the changes that have been made in the procedures used for the analysis of respirable coal mine dust samples for quartz and discusses the current procedures used by MSHA to analyze such samples. Factors affecting the analysis such as optimization of the deposit size of the ashed sample, the importance of centering the sample in the infrared beam, baseline selection points, and peak measurement techniques, as well as the quality assurance procedure and the precision of the analysis, are discussed.
Utilization of an Asphalt Pavement Analyzer for Hot Mix Asphalt Laboratory Mix Design
Authors: Williams RC , Hill DW , Rottermond MP
Published: March 2005

The Superpave volumetric mix design system, developed by SHRP in the 1990s, has continued to gain widespread acceptance across the United States. Although it is widely believed to be an improvement over past mix design systems, it does have an inherent flaw. It does not include a performance test to assess HMA's resistance to rutting, fatigue, or low temperature cracking. With the development and implementation of newer performance test specifications, it is an appropriate time to work on integrating a performance based test for construction specifications. Rather than being based on material properties or construction practices, the payment for an HMA pavement could then be based primarily on the performance based specification. The results of this study indicate that although the APA works well as the pass/fail criterion used by state agencies, the variability of APA cycles to failure make it impractical to base a rut prediction model on data obtained from it.
In-Situ Studies of the Oxide Film Properties on BWR Fuel Cladding Materials
Authors: Bojinov M , Hansson-Lyyra L , Kinnunen P , Saario T , Sirkiä P
Published: March 2005

The pre-transition oxides formed on five different types of Zircaloy-2 alloys have been characterized in-situ using electrochemical impedance spectroscopy (EIS) in high-temperature water simulating BWR conditions at 300°C. The contribution of the oxide film properties to the impedance spectra has been distinguished from the contribution of the corrosion reaction by performing additional EIS measurements in a gas atmosphere. To obtain a correlation between the oxide film thickness, the oxide growth rate, and the impedance parameters, the EIS data have been fitted to the transfer functions derived from the Mixed Conduction Model for oxide films. As a result, the oxide growth rate of each alloy has been calculated assuming that the growth rate is proportional to the flux of oxygen vacancies through the film. The values of the oxide film thickness based on the model calculations have proved to be in good agreement with the values measured from the cross-section micrographs of the specimens using scanning electron microscopy (SEM). The measured corrosion properties have been qualitatively correlated to the secondary phase particle distributions of the five fuel cladding materials. However, to establish a quantitative correlation between the corrosion rates and the second phase particle distributions of these alloys, more data on the microstructure of the metal-oxide interface are needed.
The Effect of Aluminum Content Variation on Burning Rate, Pressure-Propellant Area Ratio Relationship, and Other Properties of Hydroxyl Terminated Polybutadiene Based Composite Propellants
Authors: Nihal Tüzün F
Published: March 2005

In this study, three different HTPB (hydroxyl terminated polybutadiene) based composite propellants were developed by varying the aluminium (Al) content 16, 18, and 20 %; and the effect of aluminium content variation on burning rate, P-K relationship, viscosity, heat of explosion, density, and hardness of the propellants developed were investigated. Propellants were cured at 65°C for 7 days, and then applied to the small test motors and kept at three different temperatures (−42, −15, and 50°C) for a night (8 h) before testing. Tests on the small motors were performed with three different K values (200, 250, and 300) statically. As a result of this, two relationships were determined, and the coefficients of those relationships are also given in Table 1.

First relationship: P = d Ky (1), where P = pressure; y = K index; d = P-K relationship constant; and K = Propellant-area ratio. This relationship shows that pressure is highly affected by K values at 50°C in each of three compositions.

Second relationship: r = a Pn (2), where P = pressure; r = burning rate; a = burning rate constant; and n = combustion index.

This relationship also shows that burning rate has the lowest value in the propellant containing 20 % Al. Therefore; it was observed that the burning rate exponent (n) was below the safety limit value of 0.4 in three compositions, which shows that Al content should not exceed 18 %. These results also indicate that viscosity and hardness remain constant, density increases, and heat of explosion decreases with increasing Al content in the three compositions.
Developmental Switch in Synaptic Mechanisms of Hippocampal Metabotropic Glutamate Receptor-Dependent Long-Term Depression
Authors: Nosyreva Elena D. , Huber Kimberly M.
Published: March 2005

The presynaptic and postsynaptic properties of synapses change over the course of postnatal development. Therefore, synaptic plasticity mechanisms would be expected to adapt to these changes to facilitate alterations of synaptic strength throughout ontogeny. Here, we identified developmental changes in long-term depression (LTD) mediated by group 1 metabotropic glutamate receptors (mGluRs) and dendritic protein synthesis in hippocampal CA1 slices (mGluR-LTD). In slices prepared from adolescent rats [postnatal day 21 (P21) to P35], mGluR activation induces LTD and a long-term decrease in AMPA receptor (AMPAR) surface expression, both of which require protein synthesis. In neonatal animals (P8-P15), mGluR-LTD is independent of protein synthesis and is not associated with changes in the surface expression of AMPARs. Instead, mGluR-LTD at neonatal synapses results in large decreases in presynaptic function, measured by changes in paired-pulse facilitation and the rate of blockade by the use-dependent NMDA receptor blocker (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate. Conversely, mGluR-LTD at mature synapses results in little or no change in presynaptic function, suggesting a postsynaptic mechanism of expression. The developmental switch in the synaptic mechanisms of LTD would differentially affect synapse dynamics and perhaps information processing over the course of postnatal development.
Involvement of Cannabinoid Receptors in the Regulation of Neurotransmitter Release in the Rodent Striatum: A Combined Immunochemical and Pharmacological Analysis
Authors: Köfalvi Attila , Rodrigues Ricardo J. , Ledent Catherine , Mackie Ken , Vizi E. Sylvester , Cunha Rodrigo A. , Sperlágh Beáta
Published: March 2005

Despite the profound effect of cannabinoids on motor function, and their therapeutic potential in Parkinson's and Huntington's diseases, the cellular and subcellular distributions of striatal CB1receptors are not well defined. Here, we show that CB1receptors are primarily located on GABAergic (vesicular GABA transporter-positive) and glutamatergic [vesicular glutamate transporter-1 (VGLUT-1)- and VGLUT-2-positive] striatal nerve terminals and are present in the presynaptic active zone, in the postsynaptic density, as well as in the extrasynaptic membrane. Both the nonselective agonistWIN55212-2 [(R)-(+)-[2,3-dihydro-5-methyl-3[(4-morpholinyl)methyl] pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl)methanone mesylate salt] (EC50, 32 nm) and the CB1-selective agonist ACEA [N-(2-chloroethyl)-5Z,8Z,11Z,14Z-eicosatetraenamide] inhibited [3H]GABA release from rat striatal slices. The effect of these agonists was prevented by the CB1-selective antagonists SR141716A [N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide] (1 μm) and AM251 [1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide trifluoroacetate salt] (1 μm), indicating that cannabinoids inhibit the release of GABA via activation of presynaptic CB1receptors. Cannabinoids modulated glutamate release via both CB1and non-CB1mechanisms. Cannabinoid agonists and antagonists inhibited 25 mmK+-evoked [3H]glutamate release and sodium-dependent [3H]glutamate uptake. Partial involvement of CB1receptors is suggested because low concentrations of SR141716A partly and AM251 fully prevented the effect ofWIN55212-2 and CP55940 [5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]phenol]. However, the effect of CB1agonists and antagonists persisted in CB1knock-out mice, indicating the involvement of non-CB1,CB1-like receptors. In contrast, cannabinoids did not modulate [3H]dopamine release or [3H]dopamine and [3H]GABA uptake. Our results indicate distinct modulation of striatal GABAergic and glutamatergic transmission by cannabinoids and will facilitate the understanding of the role and importance of the cannabinoid system in normal and pathological motor function.
The Role of Extracellular Adenosine in Regulating Mossy Fiber Synaptic Plasticity
Authors: Kukley Maria , Schwan Maximilian , Fredholm Bertil B. , Dietrich Dirk
Published: March 2005

Hippocampal mossy fiber synapses show unique molecular features and dynamic range of plasticity. A recent paper proposed that the defining features of mossy fiber synaptic plasticity are caused by a local buildup of extracellular adenosine (Moore et al., 2003). In this study, we reassessed the role of ambient adenosine in regulating mossy fiber synaptic plasticity in mouse and rat hippocampal slices. Synaptic transmission was highly sensitive to activation of presynaptic adenosine A1receptors (A1Rs), which reduced transmitter release by >75%. However, most of A1Rs were not activated by ambient adenosine. Field potentials increased only by 20-30% when A1Rs were fully blocked with the A1R antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) (1 μm). Moreover, blocking A1Rs hardly altered paired-pulse facilitation, frequency facilitation, or posttetanic potentiation. Frequency facilitation was similar inA1R-/-mice and when measured with NMDA receptor-mediated EPSCs in CA3 pyramidal cells in the presence of DPCPX. Additional experiments suggested that the results obtained by Moore et al. (2003) can partially be explained by their usage of a submerged recording chamber and elevated divalent cation concentrations. In conclusion, a reduction of the basal release probability by ambient adenosine does not underlie presynaptic forms of plasticity at mossy fiber synapses.
Signaling Microdomains Regulate Inositol 1,4,5-Trisphosphate-Mediated Intracellular Calcium Transients in Cultured Neurons
Authors: Jacob Simon N. , Choe Chi-Un , Uhlen Per , DeGray Brenda , Yeckel Mark F. , Ehrlich Barbara E.
Published: March 2005

Ca2+signals in neurons use specific temporal and spatial patterns to encode unambiguous information about crucial cellular functions. To understand the molecular basis for initiation and propagation of inositol 1,4,5-trisphosphate (InsP3)-mediated intracellular Ca2+signals, we correlated the subcellular distribution of components of the InsP3pathway with measurements of agonist-induced intracellular Ca2+transients in cultured rat hippocampal neurons and pheochromocytoma cells. We found specialized domains with high levels of phosphatidylinositol-4-phosphate kinase (PIPKIγ) and chromogranin B (CGB), proteins acting synergistically to increase InsP3receptor (InsP3R) activity and sensitivity. In contrast, Ca2+pumps in the plasma membrane (PMCA) and sarco-endoplasmic reticulum as well as buffers that antagonize the rise in intracellular Ca2+were distributed uniformly. By pharmacologically blocking phosphatidylinositol-4-kinase and PIPKIγ or disrupting the CGB-InsP3R interaction by transfecting an interfering polypeptide fragment, we produced major changes in the initiation site and kinetics of the Ca2+signal. This study shows that a limited number of proteins can reassemble to form unique, spatially restricted signaling domains to generate distinctive signals in different regions of the same neuron. The finding that the subcellular location of initiation sites and protein microdomains was cell type specific will help to establish differences in spatiotemporal Ca2+signaling in different types of neurons.
Stimulus-Dependent Changes in Spike Threshold Enhance Feature Selectivity in Rat Barrel Cortex Neurons
Authors: Wilent W. Bryan , Contreras Diego
Published: March 2005

Feature selectivity is a fundamental property of sensory cortex neurons, yet the mechanisms underlying its genesis are not fully understood. Using intracellular recordingsin vivofrom layers 2-6 of rat barrel cortex, we studied the selectivity of neurons to the angular direction of whisker deflection. The spike output and the underlying synaptic response decreased exponentially in magnitude as the direction of deflection diverged from the preferred. However, the spike output was more sharply tuned for direction than the underlying synaptic response amplitude. This difference in selectivity was attributable to the rectification imposed by the spike threshold on the input-output function of cells. As in the visual system, spike threshold was not constant and showed trial-to-trial variability. However, here we show that the mean spike threshold was direction dependent and increased as the direction diverged from the preferred. Spike threshold was also related to the rate of rise of the synaptic response, which was direction dependent and steepest for the preferred direction. To assess the impact of the direction-dependent changes in spike threshold on direction selectivity, we applied a fixed threshold to the synaptic responses and calculated a predicted spike output. The predicted output was more broadly tuned than the obtained spike response, demonstrating for the first time that the regulation of the spike threshold by the properties of the synaptic response effectively enhances the selectivity of the spike output.
Deriving the Glutamate Clearance Time Course from Transporter Currents in CA1 Hippocampal Astrocytes: Transmitter Uptake Gets Faster during Development
Authors: Diamond Jeffrey S.
Published: March 2005

At many excitatory synapses, the neurotransmitter glutamate diffuses beyond the synaptic cleft to activate extrasynaptic targets. The extent and impact of such transmitter “spillover” on the processing capacity of neuronal networks are unclear, in part because it remains unknown how far transmitter diffuses from its point of release before being removed from the extracellular space by high-affinity glutamate transporters. Synaptically activated, transporter-mediated currents (STCs) recorded in hippocampal astrocytes provide an experimental measure of glutamate uptake, but the time course of the STC may be shaped, or “filtered,” by other factors and therefore not represent a direct indication of clearance rate. Here, STCs were recorded from astrocytes in rat hippocampal slices under conditions in which uptake capacity was reduced and the STC decay reflected a slowed rate of glutamate clearance. The temporal characteristics of the filtering mechanisms were extracted from these responses, and the glutamate clearance time course in control conditions was derived. The results indicate that glutamate can be cleared from the extrasynaptic space within 1 ms. Clearance is fastest in adult neuropil, corresponding to a developmental increase in glial transporter expression. Synaptically released glutamate is taken up at the same rate as glutamate released via flash photolysis, indicating that the spatial location of transporters relative to the site of glutamate release does not affect the time course of clearance. Slower clearance in young animals would permit glutamate to diffuse greater distances, indicating a particularly important role for extrasynaptic receptors early in development.
Human Apolipoprotein E4 Alters the Amyloid-β 40:42 Ratio and Promotes the Formation of Cerebral Amyloid Angiopathy in an Amyloid Precursor Protein Transgenic Model
Authors: Fryer John D. , Simmons Kelly , Parsadanian Maia , Bales Kelly R. , Paul Steven M. , Sullivan Patrick M. , Holtzman David M.
Published: March 2005

Alzheimer's disease (AD) is characterized by the aggregation and deposition of the normally soluble amyloid-β (Aβ) peptide in the extracellular spaces of the brain as parenchymal plaques and in the walls of cerebral vessels as cerebral amyloid angiopathy (CAA). CAA is a common cause of brain hemorrhage and is found in most patients with AD. As in AD, the ϵ4 allele of the apolipoprotein E (apoE) gene (APOE) is a risk factor for CAA. To determine the effect of human apoE on CAAin vivo, we bred humanAPOE3andAPOE4“knock-in” mice to a transgenic mouse model (Tg2576) that develops amyloid plaques as well as CAA. The expression of both human apoE isoforms resulted in a delay in Aβ deposition of several months relative to murine apoE. Tg2576 mice expressing the more fibrillogenic murine apoE develop parenchymal amyloid plaques and CAA by 9 months of age. At 15 months of age, the expression of human apoE4 led to substantial CAA with very few parenchymal plaques, whereas the expression of human apoE3 resulted in almost no CAA or parenchymal plaques. Additionally, young apoE4-expressing mice had an elevated ratio of Aβ 40:42 in brain extracellular pools and a lower 40:42 ratio in CSF, suggesting that apoE4 results in altered clearance and transport of Aβ species within different brain compartments. These findings demonstrate that, once Aβ fibrillogenesis occurs, apoE4 favors the formation of CAA over parenchymal plaques and suggest that molecules or treatments that increase the ratio of Aβ 40:42 may favor the formation of CAA versus parenchymal plaques.
Postsynaptic Expression of Homeostatic Plasticity at Neocortical Synapses
Authors: Wierenga Corette J. , Ibata Keiji , Turrigiano Gina G.
Published: March 2005

Synaptic scaling is a form of homeostatic plasticity that scales synaptic strengths up or down to compensate for prolonged changes in activity. It has been controversial whether this plasticity is expressed presynaptically, postsynaptically, or both. Here we describe in detail the homeostatic changes that take place at excitatory synapses in visual cortical cultures after 1 or 2 d of activity blockade. After 7-10 din vitro, activity blockade significantly increased postsynaptic accumulation of synaptic AMPA receptors via proportional increases in glutamate receptor 1 (GluR1) and GluR2. Time-lapse imaging of enhanced green fluorescent protein-tagged AMPA receptors revealed that receptor accumulation increased progressively over 2 d of activity blockade and affected the entire population of imaged synapses. The strength of synaptic connections between pyramidal neurons was more than doubled after activity blockade without affecting short-term depression or the coefficient of variation of the postsynaptic responses. Furthermore, uptake of the fluorescent styryl dye FM1-43 (N-(3-triethylammoniumpropyl)-4-[4-(dibutylamino)styryl] pyridinium dibromide) by presynaptic terminals was not different at control and activity-blocked synapses. In addition to the increased accumulation of postsynaptic AMPA receptors, boosting of dendritic AMPA currents by sodium channels was increased by activity blockade. These data indicate that, at young neocortical synapses, synaptic scaling has a predominantly postsynaptic locus and functions as a gain control mechanism to regulate neuronal activity without affecting the dynamics of synaptic transmission.
Rhythmic Activity in a Forebrain Vocal Control NucleusIn Vitro
Authors: Solis Michele M. , Perkel David J.
Published: March 2005

The learned vocalizations of songbirds constitute a rhythmic behavior that is thought to be governed by a central pattern generator and that is accompanied by highly patterned neural activity. Phasic premotor activity is observed during singing in HVC [used as a proper name following the nomenclature of Reiner et al. (2004)], a telencephalic song system nucleus that is essential for song production. Moreover, HVC neurons display phasic patterns of auditory activity in response to song stimulation. To address the cellular basis of pattern generation in HVC, we investigated its rhythm-generating abilities.

We report here the induction of sustained, rhythmic activity patterns in HVC when isolatedin vitro. Brief, high-frequency stimulation evoked repetitive postsynaptic potentials (PSPs) and local field potentials (LFPs) from HVC neurons recorded in a brain slice preparation made from adult male zebra finches. These rhythmic events were sustained for seconds in the absence of ongoing, phasic stimulation, and they had temporal properties similar to those of syllable occurrence within zebra finch song. Paired recordings revealed synchrony between repetitive PSP and LFP occurrence, indicating that a population of cells participates in this patterned activity. The PSPs resulted from multiple, coordinated, fast-glutamatergic, synaptic inputs. Moreover, their occurrence and timing relied on inhibitory synaptic transmission. Thus, HVC itself has rhythmic abilities that could influence the timing of neural activity over relatively long time windows. These rhythmic properties may contribute to song production or perceptionin vivo.
Traumatic Brain Injury and Subsequent Risk of Brain Cancer in US Veterans of the Iraq and Afghanistan Wars
Authors: Stewart Ian J. , Howard Jeffrey T. , Poltavskiy Eduard , Dore Michael , Amuan Megan E. , Ocier Krista , Walker Lauren E. , Alcover Karl C. , Pugh Mary Jo
Published: February 2024

Importance

While brain cancer is rare, it has a very poor prognosis and few established risk factors. To date, epidemiologic work examining the potential association of traumatic brain injury (TBI) with the subsequent risk of brain cancer is conflicting. Further data may be useful.

Objective

To examine whether a history of TBI exposure is associated with the subsequent development of brain cancer.

Design, Setting, and Participants

A retrospective cohort study was conducted from October 1, 2004, to September 20, 2019, and data analysis was performed between January 1 and June 26, 2023. The median follow-up for the cohort was 7.2 (IQR, 4.1-10.1) years. Veterans Affairs (VA) and Department of Defense (DoD) administrative data on 1 919 740 veterans from the Long-Term Impact of Military-Relevant Brain Injury Consortium–Chronic Effects of Neurotrauma Consortium were included.

Exposure

The main exposure of interest was TBI severity (categorized as mild, moderate or severe [moderate/severe], and penetrating).

Main Outcomes and Measures

The outcome of interest was the development of brain cancer based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) or International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnostic codes in either the DoD/VA medical records or from the National Death Index.

Results

After 611 107 exclusions (predominately for no encounter during the study period), a cohort including 1 919 740 veterans was included, most of whom were male (80.25%) and non-Hispanic White (63.11%). Median age at index date was 31 (IQR, 25-42) years. The cohort included 449 880 individuals with TBI (mild, 385 848; moderate/severe, 46 859; and penetrating, 17 173). Brain cancer occurred in 318 individuals without TBI (0.02%), 80 with mild TBI (0.02%), 17 with moderate/severe TBI (0.04%), and 10 or fewer with penetrating TBI (≤0.06%). After adjustment, moderate/severe TBI (adjusted hazard ratio [AHR], 1.90; 95% CI, 1.16-3.12) and penetrating TBI (AHR, 3.33; 95% CI, 1.71-6.49), but not mild TBI (AHR, 1.14; 95% CI, 0.88-1.47), were associated with the subsequent development of brain cancer.

Conclusions and Relevance

In this cohort study of veterans of the Iraq and Afghanistan wars, moderate/severe TBI and penetrating TBI, but not mild TBI, were associated with the subsequent development of brain cancer.
Ultrastrong Nanocrystalline Inconel 718 Fabricated by Powder High‐Pressure Torsion and Annealing
Authors: Gu Gang Hee , Asghari‐Rad Peyman , Xiong Renlong , Kim Hyoung Seop
Published: February 2024

In this study, bulk nanocrystalline material is fabricated from Inconel 718 powder through a process of powder high‐pressure torsion (HPT) and subsequent annealing heat treatment. Numerous dislocations generated during the powder HPT process successfully produced bulk Inconel 718 with nanocrystalline grains during the post‐annealing treatment. In addition, the Inconel 718 exhibited additional strengthening contributions such as dislocation strengthening by high pre‐existing dislocation density and precipitation strengthening from randomly distributed precipitates. As a result of these strengthening effects, the Inconel 718 showed ultrastrong yield strength of 1.40 GPa and ultimate tensile strength of 1.53 GPa. Although the elongation of 12.0% did not indicate good ductility, the proposed Inconel 718 boasted improved mechanical properties compared to previous studies of Inconel 718 fabricated by various processing methods. The prepared Inconel 718 and its fabrication technique suggest the potential for manufacturing ultrahigh‐strength bulk nanocrystalline materials not only for Inconel 718 but also for various metallic materials using powder metallurgy.
Feasibility of Powder‐Based High‐Throughput Synthesis for Ceramics Development: Case Study on the Influence of Calcination Temperature in BiFeO3‐BaTiO3
Authors: Eckstein Udo , Kuhfuß Michel , Fey Tobias , Webber Kyle G.
Published: February 2024

Recent advances in machine learning capabilities have increased interest in materials research to improve the efficiency of materials discovery and optimization as well as to better understand the underlying phenomena responsible for the observed physical properties. While combinatorial chemistry and compositional engineering is well established in the development of pharmaceutical and chemical products, its use in the field of bulk functional polycrystalline ceramics is far from mature. In this work, a critical review of a high‐throughput powder‐based dispensing system is provided and the challenges involved with the transition from a conventional, human resources intensive workflow to a fully automated process are highlighted. Based on the lead‐free piezoelectric BiFeO3–BaTiO3binary system, the applicability and robustness of high‐throughput engineering is investigated to increase data point density in phase diagrams, including the composition variations of the resulting materials. This work presents 16 different BiFeO3–BaTiO3compositions at four different calcination temperatures, both demonstrating the potential of the system. This is coupled to automated crystal structure analysis, which will be used to investigate the role of calcination temperature on the resulting compositions at room temperature.
Non‐Destructive Tomographic Nanoscale Imaging of Ferroelectric Domain Walls
Authors: He Jiali , Zahn Manuel , Ushakov Ivan N. , Richarz Leonie , Ludacka Ursula , Roede Erik D. , Yan Zewu , Bourret Edith , Kézsmárki István , Catalan Gustau , Meier Dennis
Published: February 2024

Extraordinary physical properties arise at polar interfaces in oxide materials, including the emergence of 2D electron gases, sheet‐superconductivity, and multiferroicity. A special type of polar interface is ferroelectric domain walls, where electronic reconstruction phenomena can be driven by bound charges. Great progress has been achieved in the characterization of such domain walls and, over the last decade, their potential for next‐generation nanotechnology has become clear. Established tomography techniques, however, are either destructive or offer insufficient spatial resolution, creating a pressing demand for 3D imaging compatible with future fabrication processes. Here, non‐destructive tomographic imaging of ferroelectric domain walls is demonstrated using secondary electrons. Utilizing conventional scanning electron microscopy (SEM), the position, orientation, and charge state of hidden domain walls are reconstructed at distances up to several hundreds of nanometers away from the surface. A mathematical model is derived that links the SEM intensity variations at the surface to the local domain wall properties, enabling non‐destructive tomography with good noise tolerance on the timescale of seconds. The SEM‐based approach facilitates high‐throughput screening of materials with functional domain walls and domain‐wall‐based devices, which is essential for monitoring during the production of device architectures and quality control in real‐time.
Boosting Theranostic Performance of AIEgens Using Nanocatalyzer for Robust Cancer Immunotherapy
Authors: Li Yue , Du Zekun , Zhang Yuan , Kang Xiaoying , Song Jianwen , Chen Xiaodong , Hu Yuanbo , Yang Zhimou , Qi Ji , Shen Xian
Published: February 2024

High‐performance theranostic systems are of paramount importance for achieving precise image‐guided cancer immunotherapy. Here, a novel nanoplatform is presented that integrates aggregation‐induced emission luminogen (AIEgen) with prussian blue (PB) nanocatalyzer for robust cancer immunotherapy. The AIEgen with dimethylamine substitution demonstrates compelling near‐infrared (NIR) light‐induced photothermal conversion and photodynamic therapy (PDT) capabilities. By incorporating AIEgen into porous PBNPs, and further enveloped within M1 macrophage membrane, a tumor‐specific theranostic nanoagent is constructed. This strategic integration effectively constrains the molecular motion of AIEgen, leading to amplified NIR‐II fluorescence brightness and PDT attributes. Moreover, PBNPs can catalyze tumor‐overexpressed H2O2 to generate oxygen to boost PDT efficacy, and PB's NIR absorption also intensifies photoacoustic imaging and photothermal effect. The integration of NIR‐II fluorescence and photoacoustic imaging provides comprehensive information for photoimmunotherapy in orthotopic breast cancer‐bearing mice. Leveraging its potent immunogenic cell death effect, the nanoagent not only significantly inhibits cancer growth, but also generates a whole‐cell therapeutic cancer vaccine to protect mice from tumor rechallenge. In highly malignant post‐surgery breast cancer models, the nanoagent enables both accurate identification of residual tumors and efficient inhibition of postoperative tumor recurrence and pulmonary metastasis. This study will offer valuable insights for creating highly efficacious and multifaceted photoimmunotherapy protocols.
Design of High‐Performance Cubic N‐Type AgBiSe2 Guided by Metavalent Bonding Mechanism
Authors: Guo Zhentao , Zhu Yu‐Ke , Zhu Jianbo , Liu Ming , Dong Xingyan , Guo Fengkai , Cai Wei , Sui Jiehe , Liu Zihang
Published: February 2024

AgBiSe2 undergoes two structural transitions in its service temperature range. Increasing entropy by alloying is considered an effective solution for modulating phase transition, but the efficacy of increasing entropy is limited by solubility and the selection of alloying components depends on trial and error. This study first confirmes that trigonal AgBiSe2 is metavalently bonded and searches metavalent PbTe as the alloying material based on the 2D map spanned by quantitative chemical bonding descriptors of electrons transferred (ET) and electrons shared (ES). The large solubility can be explained by the same bonding mechanism. PbTe alloying successfully stabilizes cubic AgBiSe2 to room temperature. Further, by optimizing the carrier concentration, the average ZT value from 300 to 773 K of (AgBiSe2)0.7(PbTe)0.3Cu0.02 reaches 0.42, which is 40% higher than that of pristine AgBiSe2. Simultaneously, heavy alloying leads to solid solution strengthening with enhanced hardness. This study not only paves the way for practical applications of AgBiSe2‐based materials but also provides an effective strategy for screening potential alloying candidates to solve the structure‐transition issue from the viewpoint of chemical bonding.
Magnetic Field‐Assisted Water Splitting: Mechanism, Optimization Strategies, and Future Perspectives
Authors: Ma Shengyu , Fu Qiang , Han Jiecai , Yao Tai , Wang Xianjie , Zhang Zhihua , Xu Ping , Song Bo
Published: February 2024

Rationally designing of highly efficient electrocatalysts is critical to improving hydrogen production by water electrolysis. However, bottlenecks still require consideration when optimizing the intrinsic performance of electrocatalysts. Applying appropriate external fields to catalytic systems may effectively overcome such bottlenecks and enhance the performance of catalysts. Among various external fields, the magnetic field has received extensive attention owing to its multifunctionality, non‐contact nature, and non‐invasiveness, thereby requiring more research and development. In this review, recent advances in magnetic field‐assisted water electrolysis are systematically outlined. Firstly, the diverse methods used for pre‐regulating catalysts under magnetic fields, including optimized nucleation, induction heating, and directed growth, are discussed. It then explores the effects of magnetic fields on electrochemical processes, including magnetothermal, magnetohydrodynamic, and induced electric impact. Then, the influences of magnetic fields on the intrinsic properties of catalysts, such as spin polarization and spin reconstruction effects, are addressed. Finally, a discussion of the potential perspectives of magnetic field‐enhanced water splitting, including catalyst design, experimental precision, and in situ characterization, are then provided to guide further research.
Self‐Floating Photocatalytic System for Highly Efficient Hydrogen Peroxide Production and Organic Synthesis on Carbon Dots Decorated Conjugated Microporous Polymer
Authors: Li Xueqing , Zhang Guping , Li Najun , Xu Qingfeng , Li Hua , Lu Jianmei , Chen Dongyun
Published: February 2024

Photocatalytic oxygen (O2) reduction to hydrogen peroxide (H2O2) is considered to be a promising method for energy storage. However, it suffers from the rapid recombination of carriers, the limited solubility and slow diffusion of O2, and the self‐decomposition of H2O2 in traditional diphase systems. Here, a self‐floating carbon dots/conjugated microporous polymer (CDs/CMP) photocatalytic system is established for H2O2 production and organic synthesis. Due to the D–π–A structure, porous structure, and hydrophobicity, CMP induced the intramolecular charge transfer, exposed abundant reaction sites, and enhanced O2 adsorption. CDs act as “bridges” for electron transmission and regulate the surface hydrophobicity of CMP, further improving charge transfer and optimizing the reaction interface. CDs/CMP system exhibits a high H2O2 production of 8542.6 µmol g−1 h−1 and concurrent furoic acid production at 2.22 mm h−1. This H2O2 production rate is ≈90% higher than that in the diphase system, exceeding all previously reported photocatalysts in triphase systems. Notably, the CDs/CMP system achieves the relative separation of the photocatalysts and H2O2, suppressing the generated H2O2 self‐decomposition. Theoretical calculations and in situ characterizations reveal the mechanism of H2O2 and furoic acid evolution. This self‐floating system provides insights into exploring the application of metal‐free photocatalysts in heterogeneous reactions.
Narrow‐Band Green‐Emitting Hybrid Organic–Inorganic Eu (II)‐Iodides for Next‐Generation Micro‐LED Displays
Authors: Han Kai , Jin Jiance , Zhou Xinquan , Duan Yan , Kovalenko Maksym V. , Xia Zhiguo
Published: February 2024

Low‐dimensional metal halide perovskites are an emerging class of light‐emitting materials for LED‐based displays; however, their B‐site cations are confined to ns2, d5, and d10 metals. Here, the design of divalent rare earth ions at B‐site is presented and a novel Eu(II)‐based iodide hybrid is reported with efficient (PLQY ≈98%) narrow‐band (FWHM ≈43 nm) green emission and high thermal stability (97%@150 °C). Owing to reduced lattice vibrations and shrunken average distance of Eu(II)‐iodide bonds in the face‐sharing 1D‐structure, photoluminescence from Eu(II) 4f‐5d transition appears along with elevated crystal‐field splitting of 5d energy level. The Eu(II)‐based iodide hybrid is further demonstrated for color‐pure green phosphor‐converted LEDs with a maximum brightness of ≈396 000 cd m−2 and photoelectric efficiency of 29.2%. High‐resolution micrometer‐scale light‐emitting diode (micro‐LED) displays (2540 PPI) via the solution‐processed screen is also presented. This work thus showcases a compelling narrow‐band green emitter for commercial micro‐LED displays.
Conformation Changes Associated with the Formation and Activation of Lysine Tyrosylquinone of LOXL2 Studied by Metadynamics Simulation
Authors: Wang Yiwen , Lin Lirui , Xu Li‐Yan , Li En‐Min , Dong Geng
Published: February 2024

Lysyl oxidase‐like 2 (LOXL2) is a Cu2+‐dependent amine oxidase that catalyzes the oxidative deamination of lysine residues of elastin and collagen to generate aldehyde groups. In the active state of LOXL2, its conserved catalytic domain has a lysine tyrosylquinone (LTQ) cofactor and a copper ion. LTQ is post‐translationally derived from Lys653 and Tyr689 of LOXL2. In this study, well‐tempered metadynamics simulations are used to investigate the conformation modulation from the inactive state to active state and obtain the free energy landscape. Interestingly, the simulations show that LTQ precursor residues cannot get close in Zn2+−bound LOXL2, whereas the copper ion binding triggers a conformation change to form an optional structure for LTQ biosynthesis. It is found that a prominent loop, consisting of residues 654–658, hinders the formation of LTQ in Zn2+−LOXL2 by preventing Lys653 from moving into active site of LOXL2, whereas this loop is relatively flexible in Cu2+−LOXL2. After the formation of LTQ, it needs to be activated by adjusting its position to be exposed to the solvent, thus allowing it to react with its substrate proteins. The results indicate that this process involves an intermediate state and that the activation of LTQ overcomes an energy barrier of 5.9 kcal mol−1.
Evoked Weibel‐Palade Body Exocytosis Modifies the Endothelial Cell Surface by Releasing a Substrate‐Selective Phosphodiesterase
Authors: Naß Johannes , Terglane Julian , Zeuschner Dagmar , Gerke Volker
Published: February 2024

Weibel Palade bodies (WPB) are lysosome‐related secretory organelles of endothelial cells. Commonly known for their main cargo, the platelet and leukocyte receptors von‐Willebrand factor (VWF) and P‐selectin, WPB play a crucial role in hemostasis and inflammation. Here, the authors identify the glycerophosphodiester phosphodiesterase domain‐containing protein 5 (GDPD5) as a WPB cargo protein and show that GDPD5 is transported to WPB following uptake from the plasma membrane via an unique endocytic transport route. GDPD5 cleaves GPI‐anchored, plasma membrane‐resident proteins within their GPI‐motif, thereby regulating their local activity. The authors identify a novel target of GDPD5 , the complement regulator CD59, and show that it is released from the endothelial surface by GDPD5 following WPB exocytosis. This results in increased deposition of complement components and can enhance local inflammatory and thrombogenic responses. Thus, stimulus‐induced WPB exocytosis can modify the endothelial cell surface by GDPD5‐mediated selective release of a subset of GPI‐anchored proteins.
Convergence of Nanotechnology and Bacteriotherapy for Biomedical Applications
Authors: Liu Jun , Yuan Sichen , Bremmer Alexa , Hu Quanyin
Published: February 2024

Bacteria have distinctive properties that make them ideal for biomedical applications. They can self‐propel, sense their surroundings, and be externally detected. Using bacteria as medical therapeutic agents or delivery platforms opens new possibilities for advanced diagnosis and therapies. Nano‐drug delivery platforms have numerous advantages over traditional ones, such as high loading capacity, controlled drug release, and adaptable functionalities. Combining bacteria and nanotechnologies to create therapeutic agents or delivery platforms has gained increasing attention in recent years and shows promise for improved diagnosis and treatment of diseases. In this review, design principles of integrating nanoparticles with bacteria, bacteria‐derived nano‐sized vesicles, and their applications and future in advanced diagnosis and therapeutics are summarized.
Polyphenolic Platform Ameliorated Sanshool for Skin Photoprotection
Authors: Wang Tianyou , Guo Linghong , Wu Shuwei , Xu Yuanyuan , Song Junmei , Yang Yi , Zhang Hengjie , Li Dongcui , Li Yiwen , Jiang Xian , Gu Zhipeng
Published: February 2024

Natural evolution has nurtured a series of active molecules that play vital roles in physiological systems, but their further applications have been severely limited by rapid deactivation, short cycle time, and potential toxicity after isolation. For instance, the instability of structures and properties has greatly descended when sanshool is derived from Zanthoxylum xanthoxylum. Herein, natural polyphenols are employed to boost the key properties of sanshool by fabricating a series of nanoparticles (NPs). The intracellular evaluation and in vivo animal model are conducted to demonstrate the decreased photodamage score and skin‐fold thickness of prepared NPs, which can be attributed to the better biocompatibility, improved free radical scavenging, down‐regulated apoptosis ratios, and reduced DNA double‐strand breaks compared to naked sanshool. This work proposes a novel strategy to boost the key properties of naturally occurring active molecules with the assistance of natural polyphenol‐based platforms.
Land consolidation, cropland use, and vegetation productivity
Authors: Demirdogen Alper
Published: February 2024

Land consolidation represents a valuable tool for enhancing agricultural productivity. However, there is a notable gap in the literature, with few studies effectively estimating the impact of land consolidation on microlevel crop changes. In our study, we estimated how land consolidation affects cropland use and vegetation productivity in Turkey, specifically examining wheat and corn. To analyze microlevel datasets from various villages, we applied multiple difference‐in‐differences approaches. Our results show that land consolidation affects farmers' cropland usage, particularly transitioning from wheat to corn. Land consolidation also leads to increased yields for both wheat and corn, although these benefits are not long‐lasting and diminish within a few years. Thus, our findings provide valuable insights for land‐use policy and planning, highlighting the critical role of land consolidation in determining farmers' cropland uses and its effect on overall productivity [EconLit Citations: Q12, Q15, Q18].