bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discharge properties of pigeon single auditory nerve fibers after recovery from severe acoustic trauma
Authors: Müller M. , Smolders J.W.Th , Ding‐Pfennigdorff D. , Klünke R. 
Published: July 2002

AbstractThe time course of recovery of compound action potential (CAP) thresholds was observed in individual adult pigeons after severe acoustic trauma. Each bird had electrodes implanted on the round window of both ears. One ear was exposed to a tone of 0.7 kHz at 136–142 dB SPL for 1 hr under general anesthesia. Recovery of CAP audiograms was monitored twice a week after trauma. Single unit recordings from auditory nerve fibers were made after 3 weeks and after 4 or more months of the exposure. The CAP was abolished immediately after overstimulation in all animals. Based on the temporal patters of functional recovery of the CAP three groups of animals were identified. The first group was characterized by fast functional recovery starting immediately after trauma followed by a return to pre‐exposure values within 3 weeks. In the second group, slow functional recovery of threshold started 1–2 weeks after trauma followed by a return to pre‐exposure values by 4–5 weeks. A mean residual hearing loss of 26.3 dB at 2 kHz remained. The third group consisted of animals that did not recover after trauma. Three weeks after the exposure, tuning curves of single auditory nerve fibers were very broad and sometimes irregular in shape. Their thresholds hovered around 120 dB SPL. Spontaneous firing rate and driven rate were much reduced. Four or more months after exposure, the thresholds and sharpness of tuning of many single units were almost completely recovered. Spontaneous firing rate and driven rate were comparable to those of control animals. In the slow recovery group neuronal tuning properties showed less recovery, especially at frequencies above the exposure frequency. Thresholds and sharpness of tuning were normal at frequencies below the exposure frequency, but were much poorer at frequencies above the exposure. Spontaneous firing rate was much reduced in fibers with high characteristic frequencies. In fast recovering animals, the papilla was repopulated with hair cells after 4 months. In slow recovering animals, short (abneural) hair cells were still missing over large parts of the papilla after 4 months of recovery. Residual short (abneural) hair cell loss was largest at two areas, one more basal and the other more apical to the characteristic place of the traumatizing frequency. The results show that, in adult birds, functional recovery from severe damage to both short (abneural) and tall (neural) hair cells occurs. However, the onset of recovery is delayed and the time course is slower than after destruction of short (abneural) hair cells alone. Also, recovery is incomplete, both functionally and morphologically. There is residual permanent hearing loss, and regeneration of short (abneural) hair cells is incomplete.
The preclinical pharmacologic profile of tiapride
Authors: Scatton B. , Cohen C. , Perrault G. , Oblin A. , Claustre Y. , Schoemaker H. , Sanger D.J. , Rouquier L. , Porsolt R. 
Published: July 2002

SummaryTiapride is a benzamide derivative that has been used successfully in the clinic for a number of years for the treatment of agitation and aggressiveness in elderly patients. Like many substituted benzamides, tiapride specifically blocks dopamine receptors in the brain. It has affinity for dopamine D2 (IC50 = 110–320 nM) and D3 (IC50 = 180 nM) receptors in vitro but lacks affinity for dopamine D1 and D4 receptors and for non-dopaminergic receptors including H1, α1, α2-adrenergic and serotonergic receptors. Tiapride also shows dose-related inhibition of [3H]-raclopride binding in limbic areas and in the striatum of the rat in vivo (ED50 ∼ 20 mg/kg, ip). In microdialysis experiments, tiapride (over the range 10–30 mg/kg, ip) increased extracellular levels of dopamine in the nucleus accumbens and striatum, a reflection of its blockade of postsynaptic dopamine receptors in these brain areas.In behavioral experiments in rats, lower doses of tiapride (ED50 = 10 mg/kg, ip) antagonised dopamine agonist-induced hyperactivity while higher doses (ED50 = 60 mg/kg, ip) were required to block stereotyped movements.In addition, doses of tiapride up to 200 mg/kg, ip failed to induce catalepsy, an effect observed with many other drugs which block dopamine receptors. In tests of conditioned behavior in rats, tiapride was found to give rise to an interoceptive stimulus associated with dopamine receptor blockade at doses (ED50 = 2.2 mg/kg, ip) much lower than those producing motor disturbances or sedation (ED50 = 40 mg/kg, ip), in striking contrast to a range of conventional or atypical neuroleptics that produced interoceptive stimulus and sedation at similar doses. Furthermore, the acquisition by rats of a place-learning task in a water maze was not affected by tiapride (over the range 3–30 mg/kg, ip), whereas haloperidol (MED = 0.25 mg/kg, ip) and risperidone (MED = 0.03 mg/kg, ip) impaired performance.The preclinical pharmacologic and behavioral profile of tiapride suggests that its clinical activity may be due to a selective blockade of dopamine D2 and D3 receptors in limbic brain regions. The results are also consistent with a lack of motor or cognitive side effects.
More ‘malignant’ than cancer? Five‐year survival following a first admission for heart failure
Authors: Stewart Simon , MacIntyre Kate , Hole David J. , Capewell Simon , McMurray John J.V. 
Published: July 2002

AbstractBackground:The prognostic impact of heart failure relative to that of ‘high‐profile’ disease states such as cancer, within the whole population, is unknown.Methods:All patients with a first admission to any Scottish hospital in 1991 for heart failure, myocardial infarction or the four most common types of cancer specific to men and women were identified. Five‐year survival rates and associated loss of expected life‐years were then compared.Results:In 1991, 16224 men had an initial hospitalisation for heart failure (n ‐ 3241), myocardial infarction (n ‐ 6932) or cancer of the lung, large bowel, prostate or bladder (n ‐ 6051). Similarly, 14842 women were admitted for heart failure (n ‐ 3606), myocardial infarction (n ‐ 4916), or cancer of the breast, lung, large bowel or ovary (n ‐ 6320). With the exception of lung cancer, heart failure was associated with the poorest 5‐year survival rate (approximately 25% for both sexes). On an adjusted basis, heart failure was associated with worse long‐term survival than bowel cancer in men (adjusted odds ratio, 0.89; 95% CI, 0.82–0.97; P < 0.01) and breast cancer in women (odds ratio, 0.59; 95% CI, 0.55–0.64; P < 0.001). The overall population rate of expected life‐years lost due to heart failure in men was 6.7 years/1000 and for women 5.1 years/1000.Conclusion:With the notable exception of lung cancer, heart failure is as ‘malignant’ as many common types of cancer and is associated with a comparable number of expected life‐years lost.
Enhanced endothelin‐1‐induced contractions in mesenteric arteries from rats with congestive heart failure: role of ETB receptors
Authors: Bergdahl Anders , Valdemarsson Stig , Adner Mikael , Sun Xiang‐Ying , Hedner Tomas , Edvinsson Lars 
Published: July 2002

AbstractStudies of congestive heart failure (CHF) in man and in experimental CHF have demonstrated elevated circulating levels of endothelin (ET). In order to examine whether there are concomitant ET receptor alterations, the vasomotor effects of endothelin‐1 (ET‐1) and sarafotoxin 6c (S6c) were examined in endothelium‐intact and ‐denuded isolated mesenteric arteries from rats with CHF. CHF was induced by ligation of the left anterior descending coronary artery. Vasomotor responses were studied using small mesenteric arteries (approx. 250 μm in diameter, determined after normalisation). The antagonists IRL2500 and FR139317 were used in order to characterise the ET‐1‐induced response. In mesenteric arteries with intact endothelium, ET‐1‐induced contractions were more potent in CHF as compared to sham (pEC50 9.6 ± 0.2 and 9.1 ± 0.1, respectively, P < 0.01). In endothelium‐denuded arteries, there was no difference in potency of ET‐1 between CHF and sham arteries, or in maximum contraction. In the presence of IRL2500, a selective ETB‐receptor antagonist, ET‐1 was more potent in endothelium‐denuded arteries of CHF rats, while this difference was not seen in sham arteries. S6c had no consistent contractile or dilatory effect in CHF and sham rats. The results indicate that the enhanced contractile effects of ET‐1 noted in CHF might be due to an attenuated endothelial function and that inhibition of smooth muscle cell ETB receptors increase the effects of contractile ETA receptors in CHF rats.
Evaluation of impaired left ventricular ejection fraction and increased dimensions by multiple neurohumoral plasma concentrations
Authors: Groenning Bjoern A. , Nilsson Jens C. , Sondergaard Lars , Kjaer Andreas , Larsson Henrik B.W. , Hildebrandt Per R. 
Published: July 2002

AbstractBackgroundA range of neurohumoral substances have been suggested as diagnostic markers in heart failure. It is, however, undetermined which marker has the greatest diagnostic potential, and whether additional information is gained by a comprehensive neurohumoral evaluation.AimsThe purpose of the study was to compare the value of epinephrine, norepinephrine, renin activity, aldosterone (ALDO), atrial (ANP) and brain (BNP) natriuretic peptides, arginine‐vasopressin and endothelin (ENDO) as markers for left ventricular (LV) dimensions and ejection fraction (LVEF) in patients with systolic heart failure.MethodsForty‐eight patients with symptomatic heart failure were examined with blood samples and magnetic resonance imaging along with 20 age and gender‐matched normal controls.ResultsIn multiple regression analyses, BNP was the strongest independent marker for LV end‐diastolic (r‐0.71, P<0.0001), and end‐systolic (r‐0.75, P<0.0001) volumes, myocardial mass (r‐0.69, P<0.0001), and LVEF (r‐−0.78, P<0.0001). ANP was a supplementary independent marker for LV end‐diastolic (r‐0.76, P<0.0001) and end‐systolic (r‐0.78, P<0.0001) (ANP and BNP combined) volumes, ENDO for myocardial mass [r‐0.71, P<0.0001 (ENDO/BNP)], and ALDO for LVEF [r‐−0.81, P<0.0001 (ALDO/BNP)].ConclusionBNP is the strongest marker for LV dimensions and LVEF in patients with systolic heart failure. However, a comprehensive neurohumoral evaluation may add some information to the diagnosis.
Preventing Perinatal Transmission of HIV: An Evidence‐Based Update For Midwives
Authors: Patchen Loral , Beal Margaret W. 
Published: July 2002

ABSTRACTThis article presents an update on human immunodeficiency virus care in the United States, with an emphasis on care during pregnancy and strategies to prevent perinatal transmission. Common drug regimens are reviewed. Obstetric factors related to transmission, such as mode of delivery, also are discussed. Guidelines for collaboration between midwives and human immunodeficiency virus specialists are outlined.
A Red Light‐Triggered Drug Release System Based on One‐Photon Upconversion‐Like Photolysis
Authors: Lv Wen , Long Kaiqi , Yang Yang , Chen Sijie , Zhan Changyou , Wang Weiping 
Published: September 2020

AbstractPhotoresponsive drug release systems can enhance drug accumulation at the sites where light is applied. Nowadays, the photocleavable groups used in the systems usually require ultraviolet or blue light irradiation, which limits tissue penetration depth and is harmful to normal cells and living bodies. A one‐photon upconversion‐like photolysis strategy, which can cleave green light‐activatable prodrugs with red light at the presence of a red light‐excitable photosensitizer in organic solvents, is developed. However, both the prodrug and photosensitizer are hydrophobic and their energy transfer process is sensitive to oxygen molecules. Here, a simple strategy to address these problems by loading the two components in biocompatible and biodegradable polymeric micelles, is presented. The developed low‐irradiance red light‐triggered drug release system has a size around 40 nm and exhibits good stability in aqueous solutions. The micellar encapsulation protects the photolysis reaction from oxygen quenching in normoxia aqueous solutions. The therapeutic effect of the system enhanced by the redlight irradiation is demonstrated through in vitro and in vivo studies, indicating promising potential in cancer therapy. The study provides the first example and also an important reference for applying one‐photon upconversion‐like photolysis in biomedical applications.
Memristors Based on 2D Materials as an Artificial Synapse for Neuromorphic Electronics
Authors: Huh Woong , Lee Donghun , Lee Chul‐Ho 
Published: September 2020

AbstractThe memristor, a composite word of memory and resistor, has become one of the most important electronic components for brain‐inspired neuromorphic computing in recent years. This device has the ability to control resistance with multiple states by memorizing the history of previous electrical inputs, enabling it to mimic a biological synapse in the neural network of the human brain. Among many candidates for memristive materials, including metal oxides, organic materials, and low‐dimensional nanomaterials, 2D layered materials have been widely investigated owing to their outstanding physical properties and electrical tunability, low‐power‐switching capability, and hetero‐integration compatibility. Hence, a large number of experimental demonstrations on 2D material‐based memristors have been reported showing their unique memristive characteristics and novel synaptic functionalities, distinct from traditional bulk‐material‐based systems. Herein, an overview of the latest advances in the structures, mechanisms, and memristive characteristics of 2D material‐based memristors is presented. Additionally, novel strategies to modulate and enhance the synaptic functionalities of 2D‐memristor‐based artificial synapses are summarized. Finally, as a foreseeing perspective, the potentials and challenges of these emerging materials for future neuromorphic electronics are also discussed.
Surpassing Cu–Ta Miscibility Barriers Using a High‐Current Pulsed Arc
Authors: Mendoza‐Pérez Rafael , Bahrami Amin , Calderón‐Olvera Roxana M. , Romero‐Ibarra Josué E. , Álvarez‐Zauco Edgar , Huerta Lázaro , Muhl Stephen 
Published: September 2020

AbstractThe improvement of many applications in the fields of catalysis, surface and coatings technology, biomedicine, and fuel cells depends on the advances in nanoalloy research. Here, a structural and thermal study of nanostructures of Cu–Ta particles produced using a high‐current pulsed arc (HCPA) is presented. Structural analysis performed utilizing electron microscopy and X‐ray spectroscopy shows the formation of distinctive single crystals with grain sizes larger than 100 nm. Notably, these grains exhibit evidence of a variation of the characteristic immiscibility of Cu and Ta, as found in the bulk scale. The nonequilibrium HCPA method appears to offer a way to surpass miscibility barriers in bimetallic alloys. This technique also allows the synthesis of oxygen‐free powders in sufficient quantities to perform a variety of characterization measurements. The detailed Cu–Ta alloy crystals and oxidation temperature in a high purity oxygen atmosphere and the stability at high temperatures in argon are analyzed.
Determination of Fermi Level Position at the Graphene/GaN Interface Using Electromodulation Spectroscopy
Authors: Herman Artur P. , Janicki Lukasz , Stokowski Hubert S. , Rudzinski Mariusz , Rozbiegala Ewelina , Sobanska Marta , Zytkiewicz Zbigniew R. , Kudrawiec Robert 
Published: September 2020

AbstractGraphene together with other 2D nanomaterials, due to their exceptional physiochemical properties, are often considered as excellent building blocks for fabrication of more complex heterostructures. Despite the processing‐related issues the question of high importance for engineering of such systems is to fully understand the electronic phenomena at the interfaces. Electromodulation spectroscopy is extensively used in optical studies of semiconductors. Here, it is demonstrated that this nondestructive method may also be used to study the built‐in electric fields in a complex graphene–semiconductor heterostructures, making it possible to precisely determine the potential barrier height at the interface and therefore to assess the electrical character of the junction. The study is focused on an especially interesting graphene–semiconductor pair, i.e., graphene/GaN nevertheless it can be applied to a broad diversity of heterostructures, particularly those consisting of van der Waals crystals. The results reveal that after deposition of a graphene the Fermi level is unpinned from native GaN surface states and, instead, located at a graphene/GaN interface characteristic energy.
Zero‐Dimensional MXene‐Based Optical Devices for Ultrafast and Ultranarrow Photonics Applications
Authors: Xu Ning , Li Hongbo , Gan Yiyu , Chen Hualong , Li Wenjia , Zhang Feng , Jiang Xiantao , Shi Yihuan , Liu Jiefeng , Wen Qiao , Zhang Han 
Published: September 2020

AbstractIn recent years, MXene has become a hotspot because of its good conductivity, strong broadband absorption, and tunable band gap. In this contribution, 0D MXene Ti3C2Tx quantum dots are synthesized by a liquid exfoliation method and a wideband nonlinear optical response from 800 to 1550 nm is studied, which have a larger nonlinear absorption coefficient β of –(11.24 ± 0.14) × 10–2 cm GW–1. The carrier dynamic processes of 0D MXene are explored with ultrahigh time resolution nondegenerate transient absorption (TA) spectroscopy, which indicates that the TA signal reaches its maximum in 1.28 ps. Furthermore, 0D MXene is used to generate ultrashort pulses in erbium or ytterbium‐doped fiber laser cavity. High signal‐to‐noise (72 dB) femtosecond lasers with pulse durations as short as 170 fs with spectrum bandwidth of 14.8 nm are obtained. Finally, an ultranarrow fiber laser based on 0D MXene is also investigated and has a full width at half maximum of only 5 kHz, and the power fluctuation is less than 0.75% of the average power. The experimental works prove that 0D MXene is an excellent SA and has a promising application in ultrafast and ultranarrow photonics.
Microclusters of Kinked Silicon Nanowires Synthesized by a Recyclable Iodide Process for High‐Performance Lithium‐Ion Battery Anodes
Authors: Jeong You Kyeong , Huang William , Vilá Rafael A. , Huang Wenxiao , Wang Jiangyan , Kim Sang Cheol , Kim Yong Seok , Zhao Jie , Cui Yi 
Published: September 2020

AbstractSilicon shows great promise as a high‐capacity anode material for lithium‐ion batteries. Nanostructuring silicon minimizes the impact of fracturing during charging and discharging. However, synthesizing nanostructured silicon typically requires complicated procedures with high manufacturing costs. Additionally, these complicated procedures typically have poor secondary particle formation, a requirement to achieve a high tap density. Here, a cost‐effective synthesis procedure which generates nearly ideal secondary particle clusters of nanostructured silicon is developed. The cost‐effectiveness is a result of the in operando generation of silicon iodide from iodine gas and low‐grade silicon microparticle. Decomposition of silicon iodide into crystalline silicon and iodine gas enables recycling of the iodine gas, allowing for near full reutilization of iodine in the following cycles. The optimal nanostructures and microstructures of silicon synthesized by the recyclable iodide decomposition reaction enables 83.6% capacity retention over 1000 cycles. The good performance is a result of well‐maintained morphology during cycling, enabling reutilization of the solid electrolyte interphase.
Ultrahigh‐Rate Supercapacitor Based on Carbon Nano‐Onion/Graphene Hybrid Structure toward Compact Alternating Current Filter
Authors: Zhang Chenguang , Du Haozhe , Ma Ke , Yuan Zhihao 
Published: September 2020

AbstractTraditional filtering capacitors suffer from low volumetric energy density (Ev), which hinders their integration in miniaturized electronics and their high‐frequency response ability to alternating current (AC). Here, a supercapacitor based on a carbon nano‐onion (CNO)‐graphene hybrid structure concurrently possessing high Ev and ultrahigh rate capability is reported for AC filtering. The hybrid structure is synthesized on etched nickel foil using preformed monodispersed nanocrystals through a chemical vapor deposition method. The supercapacitor device shows capacitive behavior independent of voltage scan rate up to 5000 V s−1 in both aqueous and organic electrolytes, which represents a record high among the reported filtering capacitors to date. It also exhibits a high Ev of 14.9 F V2 cm−3 at 120 Hz and 28.8 mWh cm−3 at a current density of 0.25 mA cm−2. Moreover, the supercapacitor is capable of filtering AC with different waveforms at high frequencies into direct current. The hybrid structure holds promise for applications in compact filtering units. The ultrafast ion transportation performance is enabled by the highly positive surface curvature of CNOs, hierarchical interconnection of CNO particles, and the covalent interfacial bonding between CNOs and graphene.
Conversion of Methane into Liquid Fuels—Bridging Thermal Catalysis with Electrocatalysis
Authors: Yuan Shuai , Li Yanding , Peng Jiayu , Questell‐Santiago Ydna M. , Akkiraju Karthik , Giordano Livia , Zheng Daniel J. , Bagi Sujay , Román‐Leshkov Yuriy , Shao‐Horn Yang 
Published: September 2020

AbstractThe direct partial oxidation of methane to methanol promises an energy‐efficient and environmental‐friendly utilization of natural gas. Unfortunately, current technologies confront a grand challenge in catalysis, particularly in the context of distributed sources. Research has been focused on the design of homogenous and heterogenous catalysts to improve the activation of methane under thermal and electrochemical conditions. However, the intrinsic relationship between thermal and electrochemical systems has not been exploited yet. This review intends to bridge the studies of thermal and electrochemical catalysts, in both homogenous and heterogenous systems, for methane activation from a mechanistic point of view. It is expected to provide a framework to rationalize the design of electrocatalysts beyond the state of art. First, methane activation systems reported previously are reviewed and classified into two basic mechanisms: dehydrogenation and deprotonation. Based on the mechanism types, activity and selectivity descriptors are defined to understand the performance of current catalysts and guide the design of future catalysts. Moreover, methods to enhance the activity and selectivity are discussed to emphasize the unique advantage of electrocatalysis in overcoming the limitations of traditional thermal catalysis. Finally, immense opportunities and challenges for catalyst design are discussed by unifying thermal and electrochemical catalysis.