bluuebunny/crossref_metadata_2025_split huggingface dataset:
High mechanical efficiency of the cross-bridge powerstroke in skeletal muscle
Authors: Sugi Haruo , Iwamoto Hiroyuki , Akimoto Tsuyoshi , Kishi Hirohiko 
Published: February 2003

SUMMARY
We were interested to estimate the maximum mechanical efficiency with which chemical energy derived from ATP hydrolysis is converted into mechanical work by individual cross-bridges when they perform their powerstroke synchronously. Glycerinated rabbit psoas muscle fibres, containing ATP molecules almost equal in number to the cross-bridges within the fibre, were activated to shorten under various afterloads by laser-flash photolysis of caged Ca2+. In these conditions, almost all the cross-bridges are in the state where the ATP is hydrolyzed but the products have not yet been released from the cross-bridge (M-ADP-Pi) immediately before activation, and can hydrolyze only one ATP molecule during the flash-induced mechanical response. Power output records of the fibres following activation indicated that the cross-bridges actually started their powerstroke almost synchronously. The amount of ATP utilized at 1 s after activation was estimated from the amount of isometric force developed after interruption of fibre shortening, while the amount of work done was calculated by multiplying the amount of afterload by the distance of fibre shortening. A conservative estimation of the maximum mechanical efficiency at a load of 0.5–0.6 Po was 0.7, suggesting that the actual maximum mechanical efficiency of cross-bridge powerstrokes may be close to unity.
Evolution of water conservation mechanisms inDrosophila
Authors: Gibbs Allen G. , Fukuzato Fernando , Matzkin Luciano M. 
Published: February 2003

SUMMARYFlies of the genus Drosophila inhabit a wide range of habitats,from the tropics to deserts to boreal forests. The primary physiological mechanism allowing Drosophila and other insects to survive in arid habitats is a reduction in rates of water loss. To understand mechanisms of water retention in greater detail, we investigated the three main routes by which Drosophila lose water: excretion, cuticular transpiration and respiratory loss through the spiracles. Excretory losses comprised &lt;6% of total water flux and did not differ between xeric (cactophilic) and mesic species. No consistent relationship was observed between water-loss rates and the composition, physical properties or amounts of cuticular hydrocarbons,suggesting that cuticular transpiration did not differ among species from different habitats. Metabolic rates and water-loss rates were highly correlated. Cactophilic Drosophila were less active, and female cactophiles had lower metabolic rates than female mesic species of the same size. They were also more likely to exhibit a pattern of cyclic CO2release that may help to conserve water. We conclude that lower overall rates of water loss are achieved primarily by reduction of respiratory losses.
Modulation of foregut synaptic activity controls resorption of molting fluid during larval molts of the mothManduca sexta
Authors: Bestman Jennifer E. , Booker Ronald 
Published: February 2003

SUMMARYWe examined the role of the foregut in the resorption of molting fluid (MF)from the exuvial space during the last larval–larval molt of the moth Manduca sexta. In intermolt larvae, the activity of the foregut is characterized by robust peristaltic contractions. With the onset of the molt,MF is secreted into the exuvial space where it digests and weakens the old cuticle. The appearance of MF in the exuvial space is accompanied by a dramatic reduction in the amplitude of the foregut contractions. Foregut peristalsis returned about halfway through the molt, followed shortly by the appearance of MF in the gut. These observations suggested that larvae use their foreguts to remove MF from the exuvial space. Animals whose foreguts were surgically inactivated did not resorb their MF and most failed to successfully shed their old cuticles. The reduction in foregut motility at the onset of the molt was correlated with a sharp decline in the amplitude of the excitatory junctional potentials. With the onset of the molt there was also a decline in the number of presynaptic terminals on the foregut that loaded with the activity-dependent dye FM1-43. In the second half of the molt, the appearance of MF in the foregut and the return of foregut motility was correlated with an increase in FM1-43 loading. These data reveal that during a larval–larval molt, vesicle release and/or recycling of the presynaptic endings on the foregut muscles is modulated to assure the proper timing of MF resorption.
Age and aerobic performance in deer mice
Authors: Chappell Mark A. , Rezende Enrico L. , Hammond Kimberly A. 
Published: February 2003

SUMMARYAge impacts the phenotype of all multicellular animals, but lifetime changes in physiological traits are poorly understood for all but a few species. Here, we describe a cross-sectional study of age effects on body composition, aerobic performance and ventilation in deer mice Peromyscus maniculatus. This species lives considerably longer in captivity (in excess of 5 years) than most laboratory rodents, and the adaptational biology of its aerobic physiology is well studied. Our deer mice grew throughout life,and, as is typical for mammals, their basal metabolic rate (BMR) and maximal oxygen consumption in exercise(V̇O2max) and thermogenesis(V̇O2sum)increased as power functions of mass. Age did not affect BMR, but we found abrupt decreases in growth rate, V̇O2max and V̇O2sum at approximately 485 days of age, and the mass-adjusted maximal aerobic performance of old mice (5 years of age) was 20%(V̇O2max) to 35%(V̇O2sum) less than that of young animals. Breathing frequency (f) and oxygen extraction (EO2) also declined with age but did not change abruptly. However, there were no consistent age-related changes in tidal volume (VT) or minute volume(V̇min) after accounting for the effects of mass and V̇O2sum. Age influenced several aspects of body composition (lean and fat mass). However,these changes were insufficient to explain the age-related declines in aerobic performance, suggesting that mass-specific oxidative capacity of lean tissue decreased with age. The performance changes we found could engender substantial reductions in the mobility and thermal tolerances of old deer mice. However, very few wild mice are likely to survive to ages where substantial performance decreases occur, so these declines are probably not subjected to strong selection in natural populations.
Tolerance analysis and synthesis using the mean shift model
Authors: Stefano P Di 
Published: February 2003

Tolerance design plays an important role in the modern design process by introducing quality improvements and limiting manufacturing costs. In this paper a method for statistical tolerance analysis and synthesis is presented. This method is implemented using the mean shift model of Chase and Greenwood, providing a systematic approach to evaluate the mean shift factor. This method considers all the principal factors that affect the statistical sum of a certain number of assembly dimensions. In particular, the considered factors include the mean shift ratio, the confidence level, the number of dimension of the assembly and the tolerance assortment between the component dimensions. An implementation of the mean shift model for tolerances synthesis is described. The tolerances synthesis is performed in an unusual way, taking into account in the optimization process the typical parameters that affect the product variability. For this purpose the method uses four types of condition for the dimensional tolerances: fixed tolerance value, fixed mean shift ratio, fixed mean shift and fixed natural variability. Furthermore, in the optimization process, the service variability is considered under two conditions: fixed and valuable service variability. A case study is presented and the results of some simulations are discussed.
Shifting Innovation to Users via Toolkits
Authors: von Hippel Eric , Katz Ralph 
Published: February 2003

In the traditional new product development process, manufacturers first explore user needs and then develop responsive products. Developing an accurate understanding of a user need is not simple or fast or cheap, however. As a result, the traditional approach is coming under increasing strain as user needs change more rapidly, and as firms increasingly seek to serve “markets of one.” Toolkits for user innovation is an emerging alternative approach in which manufacturers actually abandon the attempt to understand user needs in detail in favor of transferring need-related aspects of product and service development to users. Experience in fields where the toolkit approach has been pioneered show custom products being developed much more quickly and at a lower cost. In this paper we explore toolkits for user innovation and explain why and how they work.
Current management status and spatial utilization characteristics of day‐service‐centers that can provide Chinese language service in Japan
Authors: Ding Wenlei , Matsubara Shigeki , Kita Michihiro 
Published: January 2024

AbstractThis study seeks to clarify nationwide management status and spatial utilization characteristics of day‐service‐centers that can provide Chinese language service in Japan. A comprehensive survey was conducted through mail questionnaires targeting the 115 day‐service‐centers that can provide Chinese language service in Japan, with the objective of explicating their current operational and utilization situations. Additionally, field behavioral observation surveys were carried out in 2 day‐service‐centers, 1 is for Chinese people in Japan or Japanese people from China and the other is for Japanese people. The purpose was to identify the behavioral difference between Chinese users and Japanese users and identify the spatial utilization characteristics in 2 day‐service‐centers.
Essential Fatty Acids and Osteoarthritis
Authors: Felson David T. , Misra Devyani , LaValley Michael , Clancy Margaret , Rabasa Gabriela , Lichtenstein Alice , Matthan Nirupa , Torner James , Lewis Cora E. , Nevitt Michael C. ,   for the MOST Study Investigators
Published: January 2024

ObjectiveInflammation worsens joint destruction in osteoarthritis (OA) and aggravates pain. Although n‐3 fatty acids reduce inflammation, different n‐3 fatty acids have different effects on inflammation and clinical outcomes, with eicosapentaenoic acid (EPA) having the strongest effect. We examined whether specific essential fatty acid levels affected the development of OA.MethodsWe studied participants from the Multicenter Osteoarthritis Study (MOST) at risk of developing knee OA. As part of MOST, participants were asked repeatedly about knee pain, and knee radiographs and magnetic resonance images (MRIs) were obtained. Using baseline fasting samples, we analyzed serum fatty acids with standard assays. After excluding participants with baseline OA, we defined two sets of cases based on their status through 60 months’ follow‐up: those developing incident radiographic OA and those developing incident symptomatic OA (knee pain and radiographic OA). Controls did not develop these outcomes. Additionally, we examined worsening of MRI cartilage damage and synovitis and worsening knee pain and evaluated the number of hand joints affected by nodules. In regression models, we tested the association of each OA outcome with levels of specific n‐3 and n‐6 fatty acids, adjusting for age, sex, body mass index, education, physical activity, race, baseline pain, smoking, statin use, and depressive symptoms.ResultsWe studied 363 cases with incident symptomatic knee OA and 295 with incident radiographic knee OA. The mean age was 62 years (59% women). We found no associations of specific n‐3 fatty acid levels, including EPA, or of n‐6 fatty acid levels with incident OA (eg, for incident symptomatic knee OA, the odds ratio per SD increase in EPA was 1.0 [95% confidence interval 0.87–1.17]). Results for other OA outcomes also failed to suggest a protective effect of specific n‐3 fatty acids with OA outcomes.ConclusionWe found no association of serum levels of EPA or of other specific n‐3 fatty acids or n‐6 fatty acids with risk of incident knee OA or other OA outcomes.
Engineering Triple‐Phase Boundary in Pt Catalyst Layers for Proton Exchange Membrane Fuel Cells
Authors: Li Yi , Wu Zirui , Wang Cheng , Yu Xiwen , Gao Wanguo , Wang Bing , Wu Congping , Yao Yingfang , Yang Juan , Zou Zhigang 
Published: January 2024

AbstractEngineering triple‐phase boundaries in low Pt‐loaded catalyst layers is highly desired yet challenging due to the poor Pt utilization caused by inhomogeneous Nafion ionomer coverage over catalyst nanoparticles and high mass transport resistance near catalyst surface. Herein, an effective Pt catalyst/support design strategy by using urea to modify the carbon supports is reported, in which the balance between nitrogen doping and Pt nanoparticle deposition can be well achieved without sacrificing catalyst performance. The nitrogen‐modified carbon with the positively charged surface can electrostatically attract with ionomer with negative charges in a catalyst ink. Meanwhile, ionomer can be preserved into a solid catalyst layer, forming a desirable ionomer/catalyst interface with improved dry proton accessibility and lowered oxygen transport resistance. Consequently, this interface leads to striking performance improvement in the kinetic and mass transport regions in the membrane electrode assembly level, with the current density of 1.11 A cm−2 at 0.65 V under 50% RH and 85 °C operating conditions, reaching 2.8 times this value compared with the one without modification.
Impact of Viscosity on Human Hepatoma Spheroids in Soft Core–Shell Microcapsules
Authors: Peng Xuan , Janićijević Željko , Lemm Sandy , Hauser Sandra , Knobel Michael , Pietzsch Jens , Bachmann Michael , Baraban Larysa 
Published: January 2024

AbstractThe extracellular environment regulates the structures and functions of cells, from the molecular to the tissue level. However, the underlying mechanisms influencing the organization and adaptation of cancer in three‐dimensional (3D) environments are not yet fully understood. In this study, the influence of the viscosity of the environment is investigated on the mechanical adaptability of human hepatoma cell (HepG2) spheroids in vitro, using 3D microcapsule reactors formed with droplet‐based microfluidics. To mimic the environment with different mechanical properties, HepG2 cells are encapsulated in alginate core–shell reservoirs (i.e., microcapsules) with different core viscosities tuned by incorporating carboxymethylcellulose. The significant changes in cell and spheroid distribution, proliferation, and cytoskeleton are observed and quantified. Importantly, changes in the expression and distribution of F‐actin and keratin 8 indicate the relation between spheroid stiffness and viscosity of the surrounding medium. The increase of F‐actin levels in the viscous medium can indicate an enhanced ability of tumor cells to traverse dense tissue. These results demonstrate the ability of cancer cells to dynamically adapt to the changes in extracellular viscosity, which is an important physical cue regulating tumor development, and thus of relevance in cancer biology.
A Novel N‐Type Molecular Dopant With a Closed‐Shell Electronic Structure Applicable to the Vacuum‐Deposition Process
Authors: Matsuo Takaya , Kawabata Kohsuke , Takimiya Kazuo 
Published: January 2024

AbstractRational design, synthesis, and characterization of a new efficient versatile n‐type dopant with a closed‐shell electronic structure are described. By employing the tetraphenyl–dipyranylidene (DP0) framework with two 7π‐electron systems modified with N,N‐dimethylamino groups as the strong electron‐donating substituent, 2,2′,6,6′‐tetrakis[4‐(dimethylamino)phenyl]‐4,4′‐dipyranylidene (DP7), a closed‐shell molecule with an extremely high‐lying energy level of the highest occupied molecular orbital, close to 4.0 eV below the vacuum level, is successfully developed. Thanks to its thermal stability, DP7 is applicable to vacuum deposition, which allows utilization of DP7 in bulk doping for the development of n‐type organic thermoelectric materials and contact doping for reducing contact resistance in n‐type organic field‐effect transistors. As vacuum‐deposition processable n‐type dopants are very limited, DP7 stands out as a useful n‐type dopant, particularly for the latter purpose.
Rational Modified Organic Functional Charge‐Transfer Complexes toward Optical/Photothermal Behavior Tuning through Decay Pathway Regulation
Authors: Xiang Wenxin , Sun Hua , Zhang Jiacheng , Wang Shuai , Pan Chen , Yao Lei , Ma Shuang , Li Wenju , Dan Wenyan , Zhang Jing 
Published: January 2024

AbstractDoping has been proven to be a good way to regulate the optical and electrical properties of the active elements including both inorganic and organic materials. In this paper, the study demonstrates a bipolar doping strategy for an intrinsic charge‐transfer binary‐complex through the use of p‐ and n‐type dopants, which incorporate toward highly‐ordered ternary complexes. Benefitting from the good lattice matching and energy level tuning, the supramolecular system with a large doping concentration range (0 ≤ x ≤ 50% or 40%) assembles into the original crystal lattice and exhibits tunable luminescence or quenching phenomena even at very low ratio. The 7h‐benzo[c]carbazole (BCZ) dopped cocrystals show yellow–green to red emission due to the Förster resonance energy transfer (FRET); while only 5% 7,7,8,8‐tetracyanoquinodimethane (TCNQ) dopant can bring superior photothermal (PT) behavior with a high PT conversion efficiency up to 75.3%, owing to the efficient non‐radiative decay way contribution. It is believed that the strong π–π interactions and free rotation of −C(C≡N)2 promote this decay way transition. This work on the charge‐transfer complex doping system suggests the great potential in optical, photothermal imaging, and therapy applications as well as information memory and photo sensing.
Defect Engineering of Nanocrystal‐In‐Glass Composites for Ultrashort Optical Pulse Monitoring
Authors: Lin Quanhua , Lin Xianqiu , Feng Xu , Yang Wangming , Tan Jiajia , Qiu Wenjie , Yao Shunchun , Chen Zhifeng , Qiu Jianrong , Zhou Shifeng 
Published: January 2024

AbstractThe rational control of intrinsic defects in materials can significantly enhance their scientific and technological potentials, but it remains a long‐standing challenge in nanocrystal‐in‐glass composites (NGCs). Herein, a defect engineering strategy mediated by the mixed alkali effect is proposed and experimentally demonstrated for NGCs. Interestingly, the hybridization of large alkali ions can effectively increase the barrier of Li+ migration and reduce the Li‐related defects in LiNbO3 NGC. As a result, a novel LiNbO3 NGC with greatly reduced Li‐related defects, high crystallinity of over 60%, and excellent optical transmission are successfully fabricated. This unique NGC configuration facilitates efficient transverse second harmonic generation (TSHG) in a broad wavelength region. Based on the above effects, a standard TSHG device is fabricated and implemented to monitor ultrashort optical pulses with duration in the order of ≈10−13 s over a broad wavelength region, down to 780 nm. The proposed strategy not only provides a new idea for defect engineering in materials science but also has great significance for boosting the practical applications of NGCs in ultrashort optical pulse monitoring.
Realizing Efficient Deep Blue Light‐Emitting Diodes and Single Component White Light‐Emitting Diodes with Low Efficiency Roll‐Offs from Anthracene‐Based Organic Emitters
Authors: Feng Zijun , Cheng Zhuang , Su Zihan , Wan Liang , Ge Shuyuan , Liu Hanxuan , Ma Xiaobo , Liu Futong , Lu Ping 
Published: January 2024

AbstractPurely organic emitters that can efficiently utilize triplet excitons are highly desired for organic light‐emitting diodes (OLEDs). Hot exciton channel has emerged as a competitive strategy for the efficient harvest of triplet exciton to improve the OLEDs performance and suppress efficiency roll‐off in devices. Here, two deep blue emitters, OPACN and SPACN are designed and synthesized, employing diphenylanthracene (PAnP) unit as central core, sp3 hybridized O and S atom as conjugation blocker, and electron‐withdrawing cyano group as intramolecular charge transfer (ICT) introducer. Especially, OPACN presents bluer emission with electroluminescence (EL) peak at 436 nm, CIE coordinates of (0.16, 0.10), and a maximum external quantum efficiency (EQE) of 8.7%, while SPACN shows an EL peak at 444 nm, CIE coordinates of (0.17, 0.12) and a maximum EQE of 9.0%. Furthermore, the single‐component white organic light‐emitting diode (WOLED) based on OPACN exhibits dual emission from monomer and excimer with EQE of 5.4%. And even the luminance increases to 1000–10 000 cd m−2, the EQE still remains as high as 5.2% and 4.4%, respectively, showing very low efficiency roll‐offs. These results demonstrate an alternative approach for designing high‐performance deep blue OLEDs and WOLEDs based on single component.
Tensile Stress‐Activated and Exosome‐Transferred YAP/TAZ‐Notch Circuit Specifies Type H Endothelial Cell for Segmental Bone Regeneration
Authors: Wang Feng , Li Shanyu , Kong Lingchi , Feng Kai , Zuo Rongtai , Zhang Hanzhe , Yu Yifan , Zhang Kunqi , Cao Yuting , Chai Yimin , Kang Qinglin , Xu Jia 
Published: January 2024

AbstractThe Ilizarov technique has been continuously innovated to utilize tensile stress (TS) for inducing a bone development‐like regenerative process, aiming to achieve skeletal elongation and reconstruction. However, it remains uncertain whether this distraction osteogenesis (DO) process induced by TS involves the pivotal coupling of angiogenesis and osteogenesis mediated by type H endothelial cells (THECs). In this study, it is demonstrated that the Ilizarov technique induces the formation of a metaphysis‐like architecture composed of THECs, leading to segmental bone regeneration during the DO process. Mechanistically, cell‐matrix interactions‐mediated activation of yes‐associated protein (YAP)/transcriptional co‐activator with PDZ‐binding motif (TAZ) transcriptionally upregulates the expression of Notch1 and Delta‐like ligand 4, which act as direct positive regulators of THECs phenotype, in bone marrow endothelial cells (BMECs) upon TS stimulation. Simultaneously, the Notch intracellular domain enhances YAP/TAZ activity by transcriptionally upregulating YAP expression and stabilizing TAZ protein, thus establishing the YAP/TAZ‐Notch circuit. Additionally, TS‐stimulated BMECs secrete exosomes enriched with vital molecules in this positive feedback pathway, which can be utilized to promote segmental bone defect healing, mimicking the therapeutic effects of Ilizarov technique. The findings advance the understanding of TS‐induced segmental bone regeneration and establish the foundation for innovative biological therapeutic strategies aimed at activating THECs.