bluuebunny/crossref_metadata_2025 huggingface dataset:
Full-Scale Experiment on Foam Bitumen Pavements in an Accelerated Testing Facility
Authors: Gonzalez Alvaro , Cubrinovski Misko , Pidwerbesky Bryan , Alabaster David
Published: August 2009

Foam bitumen stabilization is a viable alternative for reducing aggregate consumption in New Zealand. An accelerated full-scale experiment on foam bitumen pavements was conducted in the Canterbury Accelerated Pavement Testing Indoor Facility as part of a Transit New Zealand research project to study the effects of foam bitumen on unbound granular materials. Six pavement sections were tested. Three were constructed with foam bitumen contents of 1.2%, 1.4%, and 2.8% and with a common active filler content of 1.0% cement. Two more pavements were constructed with adding cement only (1.0%) and foam bitumen only (2.2%). In addition, one control section with the untreated unbound material was tested. Strains were collected with a three-dimension Emu soil strain system installed in each pavement section. Results showed that surface deflections decreased at sections with higher bitumen contents. After the application of 5,710,000 equivalent standard axles, the control section and all sections that had been stabilized with cement only and bitumen only showed large amounts of rutting. Conversely, little rutting was observed in the three sections stabilized with 2.2% foam bitumen and 1.0% cement. Water was introduced into these three pavements with additional accelerated loading; this caused the section with the lowest foam bitumen content to fail. These results showed that foam bitumen and cement had a significant effect on improving the performance of the materials studied. Material samples taken for indirect tensile strength (ITS) and repeat load triaxial (RLT) for laboratory tests showed that the ITS test was a good predictor of the pavement performance and produced a clear trend, although RLT results were not conclusive.
Bottom–Up Fatigue Cracking of Low-Volume Flexible Pavement Analysis from Instrumented Testing
Authors: Howard Isaac L. , James Robert S.
Published: August 2009

This paper provides general design guidance for bottom–up fatigue cracking of thin flexible pavements. Throughout the paper the need for the data is shown alongside the methods for obtaining the data and potential uses of the findings. The data were gathered as part of a study to evaluate geosynthetics in thin flexible pavements. Data were collected from strain gauges, pressure cells, and thermocouples in instrumented sections on a low-volume road in Arkansas after approximately 2,100 passes of controlled traffic with an FHWA Category 5 vehicle. More than 30,000 asphalt strain measurements were obtained. The distribution of asphalt strain measurements was heavily skewed, while the distribution of pressure measurements in the base layer was normal. Finite element analysis was used to account for temperature effects, which made the asphalt strain distributions fairly normal. Plots of damage were developed using transfer functions, finite element modeling, and the measured strains. The plots are central to the design approach, which improves the state of knowledge in mechanistic–empirical low-volume road design.
Analysis of Load Pulse Durations for Marquette Interchange Instrumentation Project
Authors: Hornyak Nicholas , Crovetti James A.
Published: August 2009

The loading frequency is an important input for determining the stiffness of asphalt materials on the basis of their dynamic modulus data. This stiffness relationship is used in the Mechanistic–Empirical Pavement Design Guide (MEPDG) to calculate a pavement's structural response to loading. This response—typically maximum horizontal strain and vertical pressure—is then used to estimate the number of load repetitions to failure. The Marquette Interchange Perpetual Pavement Instrumentation Project is a research effort carried out by the Transportation Research Center at Marquette University. The project implemented different pavement sensors to provide researchers with a complete set of pavement response data for calibration of local design variables and to provide insight into the structural behavior of a perpetual pavement opened to live urban freeway traffic. An analysis of the strain and pressure data recorded from the project was conducted to measure the length of strain and pressure pulse durations. The load pulse durations for each axle were then analyzed and compared with models contained in the MEPDG software. The analysis showed that the models may broadly fit actual load durations, but the surrounding assumptions may not be adequate for all axle and load configurations.
Effectiveness of Tire-Tread Patterns in Reducing the Risk of Hydroplaning
Authors: Fwa T. F. , Kumar Santosh S. , Anupam Kumar , Ong G. P.
Published: August 2009

Grooving of tire tread is necessary to provide sufficient skid resistance for wet-weather driving and to reduce the risk of hydroplaning. Many different groove patterns of tire tread are found in the market. However, their relative effectiveness in reducing hydroplaning risk is generally not known to motorists and highway engineers. The effects of changes in the groove depth of a tire tread's groove pattern also deserve further investigation. This paper presents an analytical study that aims to characterize quantitatively the influence of different tire-tread patterns and groove depths on the hydroplaning behavior of passenger cars. The analysis is performed by means of a computer simulation model with a three-dimensional finite element approach. The following six forms of tire-tread groove patterns are considered: ( a) longitudinal groove pattern, (b) transverse groove pattern, ( c) V-groove pattern with 20° V-cut, (d) V-groove pattern with 40° V-cut, ( e) combined groove pattern consisting of longitudinal grooves and edge horizontal grooves, and ( f) combined groove pattern consisting of longitudinal grooves and 20° V-cut grooves. The analysis shows that a parameter computed as the groove volume per tread area of the tire is a useful performance indicator to assess the effectiveness of various tire-tread groove patterns in reducing vehicle hydroplaning risk. The significance of V-shape grooves is discussed. For vehicular operations involving both forward and lateral movements, the analysis indicates that a combined pattern would provide a good compromise in lowering hydroplaning risk sufficiently in different modes of vehicle movements.
Practical Approach to Measuring and Reporting Friction and Macrotexture at Variable Test Speeds
Authors: Jackson N. Mike , Choubane Bouzid , Holzschuher Charles
Published: August 2009

Because of safety concerns associated with friction testing on both high-and low-speed facilities, testing at variable speeds has been investigated by the Florida Department of Transportation (DOT) and others. Previous research has demonstrated that reasonable correlations may be developed between friction test data obtained at the standard test speed of 40 mph (64.4 km/h) and other speeds. As part of an effort to harmonize its fleet of full-scale, locked-wheel friction testing equipment with portable reference test equipment (ASTM E 1960), the Florida DOT also evaluated the skid number speed gradient ( Gv) for use in transforming friction and macrotexture measurements obtained at variable highway speeds. This paper documents the results of this evaluation. On the basis of the results of this study, a practical method of measuring pavement friction and macrotexture at variable highway speeds with the Florida DOT locked-wheel test unit and the ribbed tire is presented. Since the results of the ribbed tire test are known to be significantly influenced by pavement microtexture and since the mean profile depth (MPD), as measured with the high-speed laser, is a direct measure of macrotexture, the friction number (FN)40 R and the complementary MPD data together may be readily employed to characterize the frictional properties of the pavement. This approach builds on Florida's historical database of locked-wheel, ribbed-tire test data, while adding a direct measure of macrotexture and the flexibility of testing at variable speeds. Practical implementation recommendations and examples are provided.
Early-Life, Long-Term, and Seasonal Variations in Skid Resistance in Flexible and Rigid Pavements
Authors: Ahammed M. Alauddin , Tighe Susan L.
Published: August 2009

Skidding contributes to up to 35% of wet weather accidents. Increased temperature and surface wear and polishing may affect the available friction and further increase skid-related accidents. Several studies have attempted to examine and quantify these variations mostly with inadequate or inappropriate conclusions. The surface friction of both port-land cement concrete (PCC) and asphalt concrete (AC) pavements was measured monthly to determine the influencing factors and quantify the seasonal fluctuation. Skid number (SN) and pertinent data of the Long-Term Pavement Performance program were obtained for both PCC and AC pavements, incorporating all geographic and climatic regions of the United States and Canada, to determine the contributing factors and quantify the long-term and early-life variations of surface friction. Surface friction was shown to fluctuate as a result of ambient or pavement temperature fluctuation at 0.35 British pendulum number per 1°C change in temperature. The effect of prior weather was shown to be insignificant. Following the construction, AC and PCC surface friction was shown to increase by 5 SN in about 18 months and 4 SN in about 2½ years. Skid resistance was shown to decrease thereafter at 0.27 SN for AC and at 0.24 SN for PCC pavements per million vehicle passes. Cumulative traffic passes, pavement age, speed, and temperature during the testing and PCC pavement surface texture types were found to be statistically significant for the prediction of long-term surface friction. AC pavement long-term surface friction was shown to be more sensitive, as compared with PCC, to predominant climatic condition.
Determining the Causes of Seasonal Variation in Pavement Friction
Authors: McDonald Mark P. , Crowley Larry G. , Turochy Rod E.
Published: August 2009

Large amounts of money are spent by departments of transportation to provide adequate pavement skid resistance, yet the mechanics of pavement friction are poorly characterized and not fully understood. Seasonal variations in skid resistance are often observed, and in some cases these variations may be large enough to significantly affect highway safety. This paper assesses two common theories for the cause of seasonal variations in skid resistance from the perspective of the conservation of energy to understand their influence on highway skid resistance. One theory states that the seasonal variations in skid resistance occur because snowfall removal operations increase microtexture, which is then worn away throughout the summer. The other theory states that seasonal variations are caused by seasonal differences in pavement temperature. This paper analyzes the Datapave 3.0 friction data to examine the extent to which snowfall removal operations and pavement temperatures influence highway skid resistance. The results show that although there is a significant relationship between temperature and skid number, there is no significant relationship between snowfall and skid number. This suggests that seasonal variations in pavement friction are dependent upon factors not related to surface texture and gives validity to an energy-based interpretation of the physics of the tire–pavement interface. Monthly adjustments for skid numbers were calculated and compared with those currently used by the Virginia Department of Transportation. This comparison showed significant agreement between the developed model and in-place practices.
Driving Performance and Obstructive Sleep Apnea
Authors: Brown Timothy L. , Dow Ben , Trask Doug , Dyken Mark E. , Salisbury Sue Ellen
Published: August 2009

The increasing prevalence of obstructive sleep apnea (OSA), especially among commercial vehicle operators, is a growing concern in terms of accident causation. To examine more thoroughly the relationship between severity of OSA and driving performance, a preliminary study was conducted to compare performance between drivers with untreated OSA and normal drivers. Twenty-eight adult participants, aged 27 to 66 years, completed a 45-min rural simulator drive. Several categories of driving performance, including lane keeping and velocity keeping, were evaluated. During the lane-keeping evaluation, participants with moderate to severe OSA had excursions outside the lane to the shoulder that were significantly greater in terms of time and exposure area compared with the mild and no-OSA participants. During the velocity-keeping evaluation, participants with moderate to severe OSA had significantly more variable velocity control during the later segments of the drive than did mild and no-OSA participants. On the basis of these findings, there is evidence that it will be feasible to identify differences in driving performance between various levels of OSA severity. Two potential extensions of this research could significantly impact traffic safety. The first is to further define and refine critical thresholds on the Apnea/Hypopnea Index scale at which driver performance begins to degrade. The second extension of this research is to develop a protocol and metrics for determining the effectiveness of various treatments (e.g., surgery, continuous positive airway pressure) at restoring normal driving performance.
Speed Photo–Radar Enforcement and Its Effects on Speed in Work Zones
Authors: Benekohal Rahim F. , Wang Ming-Heng , Chitturi Madhav V. , Hajbabaie Ali , Medina Juan C.
Published: August 2009

Automated speed photo–radar enforcement (SPE) in work zones was implemented for the first time in the United States in Illinois. This paper presents the results of the effectiveness of SPE on the basis of three data sets collected in two work zones. SPE was effective in reducing the average speed and increasing compliance with the work zone speed limit in all three data sets. In almost all cases in which SPE was implemented, the average speeds were significantly lower than the work zone speed limit. The average free-flowing speed of cars was reduced by 4.2 to 7.9 mph, and that of trucks by 3.4 to 6.9 mph. SPE reduced the percentage of cars and heavy vehicles exceeding the speed limit significantly. The percentages of free-flowing cars exceeding the speed limit were reduced from 39.8% to 8.3% in Data Set 1, from 30.4% to 4.2% in Data Set 2, and from 93.2% to 45.5% in Data Set 3. The percentages of free-flowing heavy vehicles exceeding the speed limit were reduced from 17.3% to 4.2% in Data Set 1; from 6.1% to 1.2% in Data Set 2; and from 69.2% to 13.9% in Data Set 3. Trucks did not exceed the speed limit by more than 10 mph in any of the data sets when SPE was implemented. In two data sets no cars exceeded the speed limit by more than 10 mph, while in the third data set only 2.5% did. Field data were also collected after the SPE van left the work zone to examine the halo (temporal) effects of SPE. SPE had a halo effect of 1.8∼2.7 mph on free-flowing trucks in one work zone but none in the other work zone. The halo effect of SPE on free-flowing cars was a limited 1.2 mph on the shoulder lane in only one data set.
The Influence of Socioeconomic and Environmental Determinants on Health and Obesity: A West Virginia Case Study
Authors: Amarasinghe Anura , D’Souza Gerard , Brown Cheryl , Oh Hyungna , Borisova Tatiana
Published: August 2009

A recursive system of ordered self assessed health together with BRFSS data were used to investigate health and obesity in the Appalachian state of West Virginia. Implications of unobserved heterogeneity and endogeneity of lifestyle outcomes on health were investigated. Obesity was found to be an endogenous lifestyle outcome associated with impaired health status. Risk of obesity is found to increase at a decreasing rate with per capita income and age. Intervention measures which stimulate human capital development, diet-disease knowledge and careful land use planning may improve health and obesity outcomes in Appalachia in particular and rural America in general.
Molecular System Bioenergetics—New Aspects of Metabolic Research
Authors: Saks Valdur
Published: August 2009

This Special Issue is a significant step in developing a new direction of metabolic research— Molecular System Bioenergetics, which itself is a part of Systems Biology. As a new paradigm of biological sciences, Systems Biology aims at understanding of biological functions by studies and description of new, system level properties, resulting from interactions between components of biological systems at any level of organization, from molecular to population. Metabolism is the way of life of cells by exchanging mass and energy with the surrounding medium, and understanding its mechanisms requires knowledge of the complex interactions between cellular systems and components. While studies of metabolism have a long history, new concepts of Systems Biology provide useful tools for metabolic research. According to Schrödinger, living cells need to be open systems with energy and mass exchange with the surrounding medium, with the aim of maintaining their high structural and functional organization and thus their internal entropy low, achieving this by means of increasing the entropy of the medium by catabolic reactions. Thus, Schrödinger wrote: “The essential thing in metabolism is that the organism succeeds in freeing itself from all entropy it cannot help producing while alive”. Thus, free energy conversion in the cells is an important, central part of metabolism, and understanding the complex mechanisms of its regulation is the aim of Molecular System Bioenergetics. In this Special Issue, several important problems in this field were analyzed.
Iodoarylation of Arylalkynes with Molecular Iodine in the Presence of Hypervalent Iodine Reagents
Authors: Rahman Md.  Ataur , Kitamura Tsugio
Published: August 2009

Iodoarylation of arylacetylenes was performed using a simple reagent system composed of molecular iodine and [bis(benzoyloxy)iodo]benzene. Most arylacetylenes efficiently underwent the iodoarylation reaction with electron-rich arenes to give trans 1,1-diaryl-2-iodoethene adducts regio- and stereoselectively. As an exception, the iodoarylation of p-methoxyphenylacetylene resulted in a mixture of E- and Z-isomers of the corresponding product.
High-Resolution Images with Minimum Energy Dissipation and Maximum Field-of-View in Camera-Based Wireless Multimedia Sensor Networks
Authors: Aghdasi Hadi S. , Bisadi Pouya , Moghaddam Mohsen Ebrahimi , Abbaspour Maghsoud
Published: August 2009

High-resolution images with wide field of view are important in realizing many applications of wireless multimedia sensor networks. Previous works that generally use multi-tier topology and provide such images by increasing the capabilities of camera sensor nodes lead to an increase in network cost. On the other hand, the resulting energy consumption is a considerable issue that has not been seriously considered in previous works. In this paper, high-resolution images with wide field of view are generated without increasing the total cost of network and with minimum energy dissipation. This is achieved by using image stitching in WMSNs, designing a two-tier network topology with new structure, and proposing a camera selection algorithm. In the proposed two-tier structure, low cost camera sensor nodes are used only in the lower-tier and sensor nodes without camera are considered in the upper-tier which decreases total network cost as much as possible. Also, since a simplified image stitching method is implemented and a new algorithm for selecting active nodes is utilized, energy dissipation in the network is decreased by applying the proposed methods. The results of simulations supported the preceding statements.
Assessment of Global Emissions, Local Emissions and Immissions of Different Heating Systems
Authors: Henkel Johannes , Kunde Robert , Gaderer Matthias , Erdmann Georg
Published: August 2009

This paper assesses and compares existing and new technologies for space heating in Germany (e.g., heat pumps, and solar thermal and wood pellet systems) in terms of their environmental impacts. The various technologies were analyzed within the context of the new German legislation. The assessment was carried out on three levels: 1. Global emissions: a life cycle assessment was carried out in order to find the global environmental footprint of the various technologies; 2. Local emissions: the effects of local emissions on human health were analyzed; and 3. Immissions: the immissions were evaluated for the various technologies using a dispersion calculation. A special feature of this study is the substitution of frequently used database emission values by values obtained from field studies and our own measurements. The results show large differences between the different technologies: while electric heat pumps performed quite well in most categories, wood pellet systems performed the best with respect to climate change. The latter, however, are associated with high impacts in other environmental impact categories and on a local scale. The promotion of some technologies (especially systems based on fuel oil, a mixture of fuel oil and rapeseed oil, or a mixture of natural gas and biomethane) by the newly introduced German legislation is doubtful. In terms of the immissions of wood pellet systems, it can be concluded that, even for extremely unfavorable meteorological conditions, the regulatory limits are not exceeded and the heating systems have a negligible influence on the total PM load in the ambient air.
Farmers’ Willingness to Pay for Irrigation Water: A Case of Tank Irrigation Systems in South India
Authors: Chandrasekaran Karthikeyan , Devarajulu Sureshkumar , Kuppannan Palanisami
Published: August 2009

The economic value of tank irrigation water was determined through Contingency Valuation Method by analyzing farmers’ willingness to pay for irrigation water under improved water supply conditions during wet and dry seasons of paddy cultivation. Quadratic production function was also used to determine the value of irrigation water. The comparison of the economic value of water estimated using different methods strongly suggests that the present water use pattern will not lead to sustainable use of the resource in the tank command areas. Policy options for sustainable use of irrigation water and management of tanks in India were suggested.
Influences and Diffusion Effects of Lithium Contamination during the Thermal Oxidation Process of Silicon
Authors: Wandesleben Annika F. , Truffier‐Boutry Delphine , Glowacki Frédérique , Royer Agnès , Lederer Maximilian , Lilienthal‐Uhlig Benjamin , Vogt Carla
Published: April 2024

Due to the increasing number of application fields using lithium compounds in the microelectronics sector, it is necessary to investigate the contamination influence and the effects of lithium on silicon and silicon oxide. To be able to use lithium in a controlled manner in complementary metal–oxide–semiconductor clean room environments, the various diffusion effects during an important process in semiconductor manufacturing, the thermal oxidation of silicon to form silicon oxide, are investigated herein. This includes the diffusion within the wafer, between wafers, and into the furnace environment. For this purpose, wafers are intentionally contaminated, oxidized, and then analyzed with vapor phase decomposition inductively coupled plasma mass spectrometry. The results of this study are correlated with typical contamination levels in state‐of‐the‐art cleanroom facilities to enable classifications of the results for the semiconductor sector. Furthermore, the effect on the growth rate and uniformity of silicon oxide is evaluated by ellipsometry and topography measurements. Finally, electrical measurements of the oxide layer have shown that there is a significant influence on the silicon oxide quality, meaning that lithium can have a detrimental effect on devices.
Vertically Staggered Porous Ni2P/Fe2P Nanosheets with Trace Ru Doping as Bifunctional Electrocatalyst for Alkaline Seawater Splitting
Authors: Li Xiaojing , Wu Tingting , Li Na , Zhang Shuting , Chang Wenjiao , Chi Jingqi , Liu Xiaobin , Wang Lei
Published: April 2024

Designing a bifunctional electrocatalyst with high performance and low‐cost is of great significance to promote the large‐scale application of water splitting. Herein, porous Ru‐Ni2P/Fe2P heterojunction nanosheets with a vertically staggered structure are rationally fabricated to boost alkaline seawater splitting under large current densities. The Ru‐Ni2P/Fe2P catalyst exhibits remarkable activity in alkaline media, requiring only 274 and 331 mV at a large current density of 1000 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Additionally, the NiFeOOH layer formed on the surface of Ru‐Ni2P/Fe2P is proposed as the active phase to promote the OER performance. Furthermore, an anion exchange membrane (AEM) electrolyzer assembled by Ru‐Ni2P/Fe2P electrocatalyst exhibits excellent long‐term durability over 100 h, achieving a current density of 500 mA−2 at 2.0 V in alkaline seawater at 60 °C. Theoretical calculations reveal that the Ni2P/Fe2P heterojunction integration with trace Ru leads to balanced adsorption and desorption properties. Moreover, the active sites of Ru‐Ni2P/Fe2P are confirmed, in which Ni site is favorable for HER and Fe site is conducive to OER. This work provides an insight into designing a highly efficient and cost‐effective bifunctional electrocatalyst for overall seawater splitting.
Quantitative Analysis of Active Lithium Loss and Degradation Mechanism in Temperature Accelerated Aging Process of Lithium‐Ion Batteries
Authors: Peng Yufan , Zhong Cong , Ding Meifang , Zhang Huiyan , Jin Yanting , Hu Yonggang , Liao Yiqing , Yang Lufeng , Wang Shengxiang , Yin Xiaoting , Liang Jinding , Wei Yimin , Chen Jie , Yan Jiawei , Wang Xuefeng , Gong Zhengliang , Yang Yong
Published: April 2024

Quantifying the aging mechanisms and their evolution patterns during battery aging is crucial for enabling renewable energy. Here, key factors are monitored and quantified affecting the aging processes of LiFePO4//graphite battery by a combination of mass spectrometry titration (MST), nuclear magnetic resonance (NMR), cryogenic transmission electron microscopy (cryo‐TEM), and neutron imaging techniques. Electrochemical analysis reveals the loss of active lithium inventory drives battery aging as temperature increases. It is shown that temperature‐induced accelerated decaying rate is 2.01 and 3.45 times at 45 and 65 °C compared with that of rate at 25 °C. Quantitative analysis indicates that irreversible formation of LixC6 (x ≤ 1), LiF, ROCO2Li, LiH, Li2C2, and RLi (R = CH3, C2H3, C2H5, C3H5) are the primary components of inactive lithium. The solid eletrolyte interpahse (SEI), excluding LixC6, constitutes over 70% of the total inactive lithium. With increasing cycles, SEI shows a decreasing proportion of LiF and an increasing proportion of ROCO2Li. The coupled effects of substantial SEI growth, increased irreversible formation of LixC6, and worsened conductivity result in the rapid aging of batteries tested at high temperatures. In this work, a research toolbox for the quantitative study of aging mechanisms in practical batterysystems has been provided.
Multifunctional Composite Scaffold with Nanosilver, Graphene Oxide, and Macrophage Membrane Vesicles for Sequential Treatment of Infected Bone Defects
Authors: Sun Mingjie , Lu Yang , Zhang Hongrui , Jiang Weiqian , Wang Wenzhao , Huang Xiao , Zhang Shichun , Xiang Dulei , Tang Boyu , Chen Yu , Chen Tingmei , Lian Chengjie , Zhang Jian
Published: April 2024

The management of infected bone defects poses a significant clinical challenge, and current treatment modalities exhibit various limitations. This study focuses on the development of a multifunctional composite scaffold comprising nanohydroxyapatite/polyethyleneglycol diacrylate matrix, silver nanoparticles, graphene oxide (GO), sodium alginate, and M2‐type macrophage membrane vesicles (MVs) to enhance the healing of infected bone defects. The composite scaffold demonstrates several key features: first, it releases sufficient quantities of silver ions to effectively eliminate bacteria; second, the controlled release of MVs leads to a notable increase in M2‐type macrophages, thereby significantly mitigating the inflammatory response. Additionally, GO acts synergistically with nanohydroxyapatite to enhance osteoinductive activity, thereby fostering bone regeneration. Through meticulous in vitro and in vivo investigations, the composite scaffold exhibits broad‐spectrum antimicrobial effects, robust immunomodulatory capabilities, and enhanced osteoinductive activity. This multifaceted composite scaffold presents a promising approach for the sequential treatment of infected bone defects, addressing the antimicrobial, immunomodulatory, and osteogenic aspects. This study introduces innovative perspectives and offers new and effective treatment alternatives for managing infected bone defects.
Ultrabright Dibenzofluoran‐Based Polymer Dots with NIR‐IIa Emission Maxima and Unusual Large Stokes Shifts for 3D Rotational Stereo Imaging
Authors: Chowdhury Partha , Lu Zhao‐Yu , Su Shih‐Po , Liu Meng‐Huan , Lin Chun‐Yi , Wang Man‐Wen , Luo Yi‐Chi , Lee Yi‐Jang , Chiang Huihua Kenny , Chan Yang‐Hsiang
Published: April 2024

Emerging organic molecules with emissions in the second near‐infrared (NIR‐II) region are garnering significant attention. Unfortunately, achieving accountable organic emission intensity over the NIR‐IIa (1300 nm) region faces challenges due to the intrinsic energy gap law. Up to the current stage, all reported organic NIR‐IIa emitters belong to polymethine‐based dyes with small Stokes shifts (<50 nm) and low quantum yield (QY; ≤0.015%). However, such polymethines have proved to cause self‐absorption with constrained emission brightness, limiting advanced development in deep‐tissue imaging. Here a new NIR‐IIa scaffold based on rigid and highly conjugated dibenzofluoran core terminated by amino‐containing moieties that reveal emission peaks of 1230–1305 nm is designed. The QY is at least 10 times higher than all synthesized or reported NIR‐IIa polymethines with extraordinarily large Stokes shifts of 370–446 nm. DBF‐BJ is further prepared as a polymer dot to demonstrate its in vivo 3D stereo imaging of mouse vasculature with a 1400 nm long‐pass filter.
Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics
Authors: Manoharan Divinah , Wang Liu‐Chun , Chen Ying‐Chi , Li Wei‐Peng , Yeh Chen‐Sheng
Published: April 2024

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio‐chemical features, such as high surface‐to‐volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio‐chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti‐inflammation, and anti‐aging. In addition, the catalytic activity of nanozymes can specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, a systematic and comprehensive review of the challenges and recent development of CNPs for biomedical applications is presented from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, the biosafety issue of applying biodegradable and non‐biodegradable nanozymes and future perspectives are critically discussed to guide a promising direction in developing span‐new nanozymes and more intelligent strategies for overcoming the current clinical limitations.
Extraordinary Thermoelectric Properties of Topological Surface States in Quantum‐Confined Cd3As2 Thin Films
Authors: Ouyang Wenkai , Lygo Alexander C. , Chen Yubi , Zheng Huiyuan , Vu Dung , Wooten Brandi L. , Liang Xichen , Heremans Joseph P. , Stemmer Susanne , Liao Bolin
Published: April 2024

Topological insulators and semimetals have been shown to possess intriguing thermoelectric properties promising for energy harvesting and cooling applications. However, thermoelectric transport associated with the Fermi arc topological surface states on topological Dirac semimetals remains less explored. This work systematically examines thermoelectric transport in a series of topological Dirac semimetal Cd3As2 thin films grown by molecular beam epitaxy. Surprisingly, significantly enhanced Seebeck effect and anomalous Nernst effect are found at cryogenic temperatures when the Cd3As2 layer is thin. In particular, a peak Seebeck coefficient of nearly 500 µV K−1 and a corresponding thermoelectric power factor over 30 mW K−2 m−1 are observed at 5 K in a 25‐nm‐thick sample. Combining angle‐dependent quantum oscillation analysis, magnetothermoelectric measurement, transport modeling, and first‐principles simulation, the contributions from bulk and surface conducting channels are isolated and the unusual thermoelectric properties are attributed to the topological surface states. The analysis showcases the rich thermoelectric transport physics in quantum‐confined topological Dirac semimetal thin films and suggests new routes to achieving high thermoelectric performance at cryogenic temperatures.
A Highly Deficient Medium‐Entropy Perovskite Ceramic for Electromagnetic Interference Shielding under Harsh Environment
Authors: Liu Yongping , Tuo Ping , Dai Fu‐Zhi , Yu Zhiyang , Lai Wei , Ding Qi , Yan Peng , Gao Jie , Hu Yunfeng , Hu Yixuan , Fan Yuchi , Jiang Wan
Published: April 2024

Materials that can provide reliable electromagnetic interference (EMI) shielding in highly oxidative atmosphere at elevated temperature are indispensable in the fast‐developing aerospace field. However, most of conductor‐type EMI shielding materials such as metals can hardly withstand the high‐temperature oxidation, while the conventional dielectric‐type materials cannot offer sufficient shielding efficiency in gigahertz (GHz) frequencies. Here, a highly deficient medium‐entropy (ME) perovskite ceramic as an efficient EMI shielding material in harsh environment, is demonstrated. The synergistic effect of entropy stabilization and aliovalent substitution on A‐site generate abnormally high concentration of Ti and O vacancies that are stable under high‐temperature oxidation. Due to the clustering of vacancies, the highly deficient perovskite ceramic exhibits giant complex permittivity and polarization loss in GHz, leading to the specific EMI shielding effectiveness above 30 dB/mm in X‐band even after 100 h of annealing at 1000 °C in air. Along with the low thermal conductivity, the aliovalent ME perovskite can serve as a bifunctional shielding material for applications in aircraft engines and reusable rockets.
Work Function‐Guided Electrocatalyst Design
Authors: Chen Zhijie , Ma Tianyi , Wei Wei , Wong Wai‐Yeung , Zhao Chuan , Ni Bing‐Jie
Published: April 2024

The development of high‐performance electrocatalysts for energy conversion reactions is crucial for advancing global energy sustainability. The design of catalysts based on their electronic properties (e.g., work function) has gained significant attention recently. Although numerous reviews on electrocatalysis have been provided, no such reports on work function‐guided electrocatalyst design are available. Herein, a comprehensive summary of the latest advancements in work function‐guided electrocatalyst design for diverse electrochemical energy applications is provided. This includes the development of work function‐based catalytic activity descriptors, and the design of both monolithic and heterostructural catalysts. The measurement of work function is first discussed and the applications of work function‐based catalytic activity descriptors for various reactions are fully analyzed. Subsequently, the work function‐regulated material‐electrolyte interfacial electron transfer (IET) is employed for monolithic catalyst design, and methods for regulating the work function and optimizing the catalytic performance of catalysts are discussed. In addition, key strategies for tuning the work function‐governed material‐material IET in heterostructural catalyst design are examined. Finally, perspectives on work function determination, work function‐based activity descriptors, and catalyst design are put forward to guide future research. This work paves the way to the work function‐guided rational design of efficient electrocatalysts for sustainable energy applications.
Distinguishing Elements at the Sub‐Nanometer Scale on the Surface of a High Entropy Alloy
Authors: Kim Lauren , Scougale William R. , Sharma Prince , Shirato Nozomi , Wieghold Sarah , Rose Volker , Chen Wei , Balasubramanian Ganesh , Chien TeYu
Published: April 2024

Materials in crystalline form possess translational symmetry (TS) when the unit cell is repeated in real space with long‐ and short‐range orders. The periodic potential in the crystal regulates the electron wave function and results in unique band structures, which further define the physical properties of the materials. Amorphous materials lack TS due to the randomization of distances and arrangements between atoms, causing the electron wave function to lack a well‐defined momentum. High entropy materials provide another way to break the TS by randomizing the potential strength at periodic atomic sites. The local elemental distribution has a great impact on physical properties in high entropy materials. It is critical to distinguish elements at the sub‐nanometer scale to uncover the correlations between the elemental distribution and the material properties. Here, the use of synchrotron X‐ray scanning tunneling microscopy (SX‐STM) with sub‐nm scale resolution in identifying elements on a high entropy alloy (HEA) surface is demonstrated. By examining the elementally sensitive X‐ray absorption spectra with an STM tip to enhance the spatial resolution, the elemental distribution on an HEA's surface at a sub‐nm scale is extracted. These results open a pathway towards quantitatively understanding high entropy materials and their material properties.
Conjugated Polymer Heteroatom Engineering Enables High Detectivity Symmetric Ambipolar Phototransistors
Authors: Nodari Davide , Sharma Sandeep , Jia Weitao , Marsh Adam V. , Lin Yen‐Hung , Fu Yuang , Lu Xinhui , Russkikh Artem , Harrison George T. , Fatayer Shadi , Gasparini Nicola , Heeney Martin , Panidi Julianna
Published: April 2024

Solution‐processed high‐performing ambipolar organic phototransistors (OPTs) can enable low‐cost integrated circuits. Here, a heteroatom engineering approach to modify the electron affinity of a low band gap diketopyrrolopyrole (DPP) co‐polymer, resulting in well‐balanced charge transport, a more preferential edge‐on orientation and higher crystallinity, is demonstrated. Changing the comonomer heteroatom from sulfur (benzothiadiazole (BT)) to oxygen (benzooxadiazole (BO)) leads to an increased electron affinity and introduces higher ambipolarity. Organic thin film transistors fabricated from the novel PDPP‐BO exhibit charge carrier mobility of 0.6 and 0.3 cm2 Vs⁻1 for electrons and holes, respectively. Due to the high sensitivity of the PDPP‐based material and the balanced transport in PDPP‐BO, its application as an NIR detector in an OPT architecture is presented. By maintaining a high on/off ratio (9 × 104), ambipolar OPTs are shown with photoresponsivity of 69 and 99 A W⁻1 and specific detectivity of 8 × 107 for the p‐type operation and 4 × 109 Jones for the n‐type regime. The high symmetric NIR‐ambipolar OPTs are also evaluated as ambipolar photo‐inverters, and show a 46% gain enhancement under illumination.
Elucidating the Crystallization‐Caused Phosphorescence Quenching Mechanism to Achieve Efficient Photoactivated Persistent Luminescence for High‐Quality Light Printing
Authors: Zhang Qingqing , Hu Pengtao , Han Chenyang , Mao Zhu , Chen Ruitai , Liang Zhiling , Cai Wei , Wang Leyu , Yang Zhan , Zheng Chunxiong , Liu Cong , Shi Guang , Xu Bingjia
Published: April 2024

The development of polymer‐based luminescent materials with efficient photoactivated ultralong organic phosphorescence (UOP) is of great importance but very challenging. Herein, a new class of organic phosphorescent luminogens is constructed by attaching phenyl rings and/or ethyl benzoates to the nitrogen atoms of a planar aromatic heterocycle pyrrolodiindole (PDI). The compounds show a significant elevation in phosphorescence emission capability after incorporating the ester group(s). However, they cannot produce room‐temperature phosphorescence in the crystalline state. These observations are identified to be associated with the formation of dimers and excimers and the motions of substituents within the molecules. In this context, the PDI derivatives are doped into epoxy polymers with compact and permanent 3D covalent networks. The resulting polymer films show reversible photoactivated UOP under ambient conditions, with quantum yields and lifetimes of up to 24.4% and 2.03 s, respectively, thereby enabling high‐quality and erasable light printing and multi‐level anti‐counterfeiting applications. In addition, they also exhibit excellent water and chemical resistance. This work is conducive to understanding the generation and decay mechanisms of the triplet excitons of organic luminophores with planar aromatic heterocycles in the crystalline state and provides a direction for the development of high‐performance photoactivated UOP materials.
Quantitative and qualitative analysis of stability for 16 serum immunoregulators over 50 freeze–thaw cycles
Authors: Chowdhury R. N. , Armato A. , Culver E. , Shteynman L. , Kurien C. , Cradin B. , Margolin F. , Nguyen T. , Cardona C. , Kabir N. , Garruto R. M. , Lum J. K. , Wander K.
Published: April 2024

Objectives

To evaluate the reliability of data from the assay of bio‐archived specimens, a 50‐freeze–thaw‐cycle (FTC) degradation study of fresh sera was conducted to test the stability of 16 immunoregulators.

Methods

Twenty de‐identified serum specimens were obtained from volunteers at United Health Services‐Wilson Memorial Hospital. Specimens were stored at −20°C and underwent daily 1 h thawing and subsequent freezing for each FTC over 50 consecutive days. Immunoregulator concentrations were assessed via enzyme‐linked immunosorbent assay (ELISA) in participant samples at 2 FTC (baseline), 25 FTC, and 50 FTC. Specific immunoregulators observed in the study were C‐reactive protein (CRP), interleukin (IL)‐1α, 4, 6, 8, 10, monocyte chemoattractant protein‐1 (MCP‐1, CCL2), monocyte chemoattractant protein‐2 (MCP‐2, CCL8), eotaxin‐1, thymus‐and‐activation‐regulated chemokine (TARC, CCL17), regulated on activation normal T‐cell expressed and secreted (RANTES, CCL5), growth‐regulated oncogene‐alpha (GRO‐α, CXCL1), small inducible cytokine A1 (I‐309, CCL1), interferon‐gamma (IFN‐γ), interferon‐gamma inducible protein‐10 (IP‐10, CXCL10), and tumor necrosis factor‐alpha (TNF‐α).

Results

Quantitative stability of serum immunoregulators: Serum CRP, IL‐8, IL‐10, IFN‐γ, IP‐10, and eotaxin‐1 levels appear to be statistically equivalent from baseline to 50 FTC (p ≤ .05). Retention of patterns in serum immunoregulators: patterns across FTC were retained for TARC (age) and CRP, IFN‐γ, and MCP‐2 (sex).

Conclusions

While the effect of multiple FTC on serum immunoregulator levels may not replicate prolonged freezer storage, the results of this study provide valuable information on the robustness of immunoregulators for research using bio‐archived sera.
An Efficient Synthesis of α‐Sulfonamide Phosphonates through Metal‐Free Three‐Component Reaction
Authors: Ramani Arti , Bhavyesh Desai , Kanta Koppolu Mani , Chinna Ashalu Kashamalla , Begari Eeshwaraiah , Naveen Togati
Published: April 2024

A metal‐free three‐component reaction for the direct synthesis of α‐sulfonamide phosphonates involving sulfonamide derivatives, benzaldehyde derivatives, and diethyl phosphite, has been achieved with high yields using ethanol as a green solvent. This efficient method reduces reaction time and minimizes the use of excess reagents. Hitherto, no reports have been found in the literature for the direct synthesis of α‐sulfonamide phosphonates from the readily available aldehydes, diethyl phosphite, and sulfonamides, emphasizing the novelty and significance of this work.
Comparing short‐axis versus long‐axis ultrasound‐guided techniques for internal jugular vein cannulation: A meta‐analysis of clinical outcomes and safety
Authors: AlGhamdi Faisal , AlJoaib Nasser , Aldawood Ali , AlGhamdi Mohammed , AlMulhim Abdullah
Published: April 2024

Introduction

Central venous access plays a crucial role in various clinical settings, and ultrasound guidance has become increasingly popular for improving its safety and success rates. The aim of this meta‐analysis was to compare the short‐axis (SAX) and long‐axis (LAX) ultrasound‐guided techniques for internal jugular vein (IJV) cannulation in terms of first needle pass success rate, number of cannulation attempts, access time, guidewire insertion time, posterior IJV wall puncture, arterial puncture, haematoma and catheter‐related bloodstream infection.

Methods

A comprehensive literature search was conducted, and randomised controlled trials (RCTs) comparing SAX and LAX techniques for IJV cannulation on adults were included.

Results

A total of 11 RCTs involving 1183 patients were included in the meta‐analysis. The SAX technique demonstrated a significantly greater first needle pass success rate and faster IJV access time compared to the LAX technique. However, more posterior IJV wall puncture was significantly associated with the SAX technique. There was no significant difference between the two techniques in terms of number of cannulation attempts, guidewire insertion time, arterial puncture, haematoma and catheter‐related bloodstream infection.

Conclusion

This meta‐analysis suggests that the SAX technique may have advantages over the LAX technique in terms of first needle pass success rate and potentially reducing cannulation attempts and access time. However, the occurrence of posterior IJV wall puncture raises concerns. The decision on the choice of technique should be based on individual patient factors and operator proficiency.