bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of solvent composition on molecular ion response in electrospray mass spectrometry: Investigation of the ionization processes
Authors: Zhou Shaolian , Hamburger Matthias 
Published: May 2005

AbstractElectrospray ionization of four structurally diverse natural products, actinomycin D, digitoxin, reserpine and quercetin was investigated. Specific attention was paid to the molecular ions formed under typical reversed‐phase high‐performance liquid chromatography (RP‐HPLC) conditions. The response characteristics of [M + H]+, [M + NH4]+ and [M + Na]+ Ions, observed upon addition of formic acid, ammonium formate and sodium acetate were studied. It was found that the highest response for these molecular ions was obtained with proton, ammonium and sodium ion concentrations of approximately 10−3 ∼ 10−4 M. This critical concentration appears to be correlated with the equilibrium between the thermodynamically controlled molecular ions in solution and electrospray produced gas‐phase ions. Gas‐phase ion reactions in the ion transfer region were investigated for digitoxin, and the mechanism of gas‐phase ion formation is briefly discussed.
Direct database searching with MALDI‐PSD spectra of peptides
Authors: Griffin Patrick R. , Maccoss Michael J. , Blevins Richard A. , Aaronson Jeffrey S. , Eng Jimmy K. , Yates Iii John R. , 
Published: May 2005

AbstractThe analysis of matrix‐assisted laser desorption ionization post‐source decay (MALDI‐PSD) mass spectra of peptides by using the cross‐correlation method for database searching is illustrated. MALDI‐PSD mass spectra are shown to contain sufficient fragmentation information to uniquely identify the correct amino acid sequence from large protein databases (∼160000 entries). A search employing the MALDI‐PSD mass spectrum of a phosphorylated peptide that correctly identifies the amino acid sequence and the site of phosphorylation is also illustrated.
Comparison of fragmentation modes for the structural determination of complex oligosaccharides ionized by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Harvey David J. , Naven T. J. P. , Küster B. , Bateman Robert H. , Green Martin R. , Critchley Glen 
Published: May 2005

AbstractFragment ions from underivatized N‐linked oligosaccharides ionized by matrix‐assisted laser desorption/ionization mass spectrometry were obtained by spontaneous fragmentation on a magnetic sector mass spectrometer, by post‐source decay (PSD) on a reflectron time‐of‐flight (TOF) instrument and by collision‐induced dissociation on a magnetic sector instrument fitted with an orthogonal‐TOF analyser. Spontaneous fragmentation on the magnetic sector instrument produced ions mainly by glycosidic cleavage together with two abundant ions formed by cross‐ring cleavage of the reducing‐terminal residue. The PSD spectra were similar, the majority of ions being formed by glycosidic cleavage. Internal fragment ions were abundant. High‐energy collision‐induced dissociation spectra, recorded with the orthogonal‐TOF analyser, differed considerably from the other types of spectra, particularly in the appearance of major fragment ions produced by cross‐ring cleavages of most of the constituent monosaccharide residues. These ions allowed much sequence and branching information to be obtained from the oligosaccharide.
Cooling time and pressure effects on competitive thermalization/activation processes by resonance excitation on ITMS
Authors: Liere P. , Bouchonnet S. , March R. E. , Tabet J. C. 
Published: May 2005

AbstractThe classical n‐butylbenzene model is used to estimate the qualitative variation of the precursor ion internal energy by the resonant excitation method in an ion‐trap mass spectrometer. The kinetic energy thermalization process is confirmed by insertion of a cooling time (⩽10ms under our conditions). An initial internal energy relaxation process due to collisions between the molecular ion and neutral species of n‐butylbenzene is proposed. The larger amount of internal energy deposited in ions as the helium pressure is increased can be explained in terms of the number of collisions between the molecular ion and helium atoms, the competition between ion dissociation and ion ejection, the rate constant of dissociation and the secular axial frequency resolution of the isolated ions. Increased analyte pressure does not accelerate the ion relaxation process, probably due to the space charge effects. In summary, variation of helium pressure and cooling time permit optimization of ion internal energy deposition leading to enhanced sensitivity in MS/MS experiments.
Functional properties of models for direction selectivity in the retina
Authors: Grzywacz Norberto M. , Koch Christof 
Published: May 2005

AbstractPoggio and Reichardt (Kybernetik, 13:223–227, 1973) showed that if the average response of a visual system to a moving stimulus is directionally selective, then this sensitivity must be mediated by a nonlinear operation. In particular, it has been proposed that at the behavioral level, motion‐sensitive biological systems are implemented by quadratic nonlinearities (Hassenstein and Reichardt: Z. Naturforsch., 11b:513–524, 1956; van Santen and Sperling: J. Opt. Soc. Am. [A] 1:451–473, 1984; Adelson and Bergen: J. Opt. Soc. Am. [A], 2:284–299, 1985). This paper analyzes theoretically two nonlinear neural mechanisms that possibly underlie retinal direction selectivity and explores the conditions under which they behave as a quadratic nonlinearity. The first mechanism is shunting inhibition (Torre and Poggio: Proc. R. Soc. Lond. [Biol.], 202:409–416, 1978), and the second consists of the linear combination of the outputs of a depolarizing and a hyperpolarizing synapse, followed by a threshold operation. It was found that although sometimes possible, it is in practice hard to approximate the Shunting Inhibition and the Threshold models for direction selectivity by quadratic systems. For instance, the level of the threshold on the Threshold model must be close to the steady‐state level of the cell's combined synaptic input. Furthermore, for both the Shunting and the Threshold models, the approximation by a quadratic system is only possible for a small range of low contrast stimuli and for situations where the rectifications due to the ON–OFF mechanisms, and to the ganglion cells' action potentials, can be linearized. The main question that this paper leaves open is, how do we account for the apparent quadratic properties of motion perception given that the same properties seem so fragile at the single cell level? Finally, as a result of this study, some system analysis experiments were proposed that can distinguish between different instances of the models.
Co‐localization of N‐acetyl‐aspartyl‐glutamate in central cholinergic, noradrenergic, and serotonergic neurons
Authors: Forloni Gianluigi , Grzanna Reinhard , Blakely Randy D. , Coyle Joseph T. 
Published: May 2005

AbstractAn immunohistochemical technique for simultaneously visualizing two different antigens has been used to investigate the presence of the acidic dipeptide, N‐acetyl‐aspartyl‐glutamate (NAAG), in cholinergic, noradrenergic‐adrenergic, and serotonergic neurons within CNS. The brain slices were processed sequentially with purified antisera against NAAG and then monoclonal antibody against choline acetyltransferase (ChAT), a marker for cholinergic neurons, or antiserum against dopamine‐β‐hydroxylase (DBH), a marker of noradrenergic‐adrenergic neurons, or antiserum against serotonin (5HT). Both antigens were revealed by the peroxidase reaction but with different chromogens, which are easily distinguishable.An intense double staining of NAAG‐like immunoreactivity (NAAG‐LI) and ChAT was observed in the motoneurons of the spinal cord as well as in the several motor components of cranial nerve nuclei including facial, ambiguus, and trigeminal nuclei. A partial colocalization of NAAG‐LI and ChAT was evident in the perikarya of the basal forebrain cholinergic system, whereas cholinergic neurons of the medial septum exhibited only sporadic staining for NAAG‐LI. A complete coexistence of NAAG‐LI and DBH was observed in the locus coeruleus. Most of the other noradrenergic and adrenergic cell groups of the medulla region exhibited substantial co‐localization with the exception of the A2 cell group, which was virtually devoid of NAAG‐LI.In the dorsal raphe, only a low percentage of serotonergic neurons stained for NAAG‐LI. The co‐existence of NAAG‐LI and serotonin was more evident in the neurons of the median raphe, although the majority of cells failed to show double staining. In the raphe pallidus and raphe magnus, the co‐existence with NAAG‐LI remained partial but involved a large percentage of serotonergic neurons. These results suggest a more widespread neuronal function of NAAG in addition to its proposed role as putative neurotransmitter in a subgroup of glutamatergic neurons.
Modification of 5‐HT neuron properties by sustained administration of the 5‐HT1A agonist gepirone: Electrophysiological studies in the rat brain
Authors: Blier Pierre , De Montigny Claude 
Published: May 2005

AbstractThe sustained administration of the 5‐HT1A agonist gepirone (15 mg/kg/day, s.c.) in the rat produced an initial decrease of the firing activity of dorsal raphe 5‐HT neurons which was followed by a progressive recovery to normal after 14 days of treatment. At this point in time, the effect of intravenous lysergic acid diethylamide (LSD) on the firing activity of 5‐HT neurons was markedly reduced, whereas those of 8‐hydroxy‐2‐N, N‐propylamino‐tetralin (8‐OH‐DPAT) and of gepirone were unchanged; however, the responsiveness of 5‐HT neurons to direct microintophoretic application of 5‐HT, LSD, 8‐OH‐DPAT, and gepirone, but not of GABA, was reduced. The responsiveness of postsynaptic dorsal hippocampus pyramidal neurons to 5‐HT, 8‐OH‐DPAT, and gepirone was not altered by the 14‐day gepirone treatment. The effectiveness of the electrical stimulation of the ascending 5‐HT pathway in reducing pyramidal neuron firing activity was not significantly modified in rats treated with gepirone for 14 days. Furthermore, this treatment did not alter the function of the terminal 5‐HT autoreceptor. It is concluded that the progressive restoration of the firing activity of 5‐HT neurons, due to a desensitization of the somatodendritic 5‐HT autoreceptor, combined with the direct activation of normosensitive postsynaptic 5‐HT1A receptor by gepirone, should result in an augmented tonic activation of postsynaptic 5‐HT1A receptors. The progressive appearance of this phenomenon would be consistent with the time course of the clinical anxiolytic, and possibly antidepressant, effects of gepirone.
PCP‐induced alterations in cerebral glucose utilization in rat brain: Blockade by metaphit, a PCP‐receptor‐acylating agent
Authors: Tamminga C. A. , Tanimoto K. , Kuo S. , Chase T. N. , Contreras P. C. , Rice K. C. , Jackson A. E. , O'Donohue T. L. 
Published: May 2005

AbstractThe effects of phencyclidine (PCP) on regional cerebral glucose utilization was determined by using quantitative autoradiography with [14C]‐2‐deoxyglucose. PCP increased brain metabolism in selected areas of cortex, particularly limbic, and in the basal ganglia and thalamus, whereas the drug decreased metabolism in areas related to audition. These results are consistent with the known physiology of central PCP neurons and may help to suggest brain areas involved in PCP‐mediated actions. Moreover, based on the behavioral similarities between PCP psychosis and an acute schizophrenic episode, these data may be relevant to the understanding of schizophrenia. The PCP‐receptoracylating agent, metaphit, blocked most of these PCP actions. In addition, metaphit by itself was found to diminish glucose utilization rather uniformly throughout brain. These results indicate an antagonist effect of metaphit on the PCP system and suggest a widespread action of metaphit, putatively at a PCP‐related site, possibly in connection with the N‐methyl‐D‐aspartate (NMDA) receptor.
Sorption of trivalent plutonium onto UO2and the effect of the solid phase on the Pu oxidation state
Authors: Olsson Mattias , Glänneskog Henrik , Jakobsson Anna-Maria , Nilsson Hans , Albinsson Yngve 
Published: May 2005

SummaryA problem with plutonium in sorption studies is its tendency to occur in a mix of oxidation states. This work was a study of the sorption of plutonium on the solid phase UO2— in a perchlorate medium as a function of pH — where plutonium is kept in its trivalent oxidation state. Experiments also showed that uranium(IV) oxide can reduce Pu(IV) to Pu(III) in an acidic solution and maintain it in that state. It was observed at the same time that the chemically inert solid phases TiO2and ThO2possibly increase the rate of disproportionation of Pu(IV) at a pH of about 0.5. In accordance with previous studies MnO2was found to have an oxidizing effect, converting Pu(IV) into Pu(VI).A comparison is made between the sorption of Th(IV), Pu(III) and Co(II) on UO2and TiO2, and Pu(VI) on TiO2.
Recovery of minor actinides from HLLW using the DIAMEX process
Authors: Serrano-Purroy Daniel , Baron P. , Christiansen Birgit , Malmbeck R. , Sorel C. , Glatz J.-P. 
Published: May 2005

Summary
In this work a hot demonstration of the DIAMEX process using the new reference molecule DMDOHEMA (N,N′-DiMethyl-N,N′-DiOctylHexylEthoxyMalonAmide) and genuine high-level PUREX raffinate as feed is reported. The continuous counter-current experiment was carried out in a 16-stage centrifugal extractor battery, installed in a hot cell. In order to produce a representative High Level Liquid Waste (HLLW) a PUREX process was applied on dissolved fuel using the same equipment. It was demonstrated that 5 extraction stages were sufficient to achieve feed decontamination factors above 2200 and 320 for Am and Cm, respectively. Co-extraction of molybdenum and zirconium, as well as of palladium, were efficiently prevented using oxalic acid and HEDTA scrubbing, respectively. However, technetium, yttrium, and to some extent ruthenium, were co-extracted. The back-extraction proved to be very efficient, yielding in 4 stages more than 99.9% recovery of Am and Cm. The extraction profiles were modeled with computer code simulations and the results compared with data obtained from an experiment using the former reference molecule DMDBTDMA (DiMethylDiButylTetraDecylMalonAmide).
Health Equity in the Veterans Health Administration From Veterans’ Perspectives by Race and Sex
Authors: Lee Natalie S. , Keddem Shimrit , Sorrentino Anneliese E. , Jenkins Kevin Ahmaad , Long Judith A. 
Published: February 2024

ImportanceAdvancing equitable patient-centered care in the Veterans Health Administration (VHA) requires understanding the differential experiences of unique patient groups.ObjectiveTo inform a comprehensive strategy for improving VHA health equity through the comparative qualitative analysis of care experiences at the VHA among veterans of Black and White race and male and female sex.Design, Setting, and ParticipantsThis qualitative study used a technique termed freelisting, an anthropologic technique eliciting responses in list form, at an urban academic VHA medical center from August 2, 2021, to February 9, 2022. Participants included veterans with chronic hypertension. The length of individual lists, item order in those lists, and item frequency across lists were used to calculate a salience score for each item, allowing comparison of salient words and topics within and across different groups. Participants were asked about current perceptions of VHA care, challenges in the past year, virtual care, suggestions for change, and experiences of racism. Data were analyzed from February 10 through September 30, 2022.Main Outcomes and MeasuresThe Smith salience index, which measures the frequency and rank of each word or phrase, was calculated for each group.ResultsResponses from 49 veterans (12 Black men, 12 Black women, 12 White men, and 13 White women) were compared by race (24 Black and 25 White) and sex (24 men and 25 women). The mean (SD) age was 64.5 (9.2) years. Some positive items were salient across race and sex, including “good medical care” and telehealth as a “comfortable/great option,” as were some negative items, including “long waits/delays in getting care,” “transportation/traffic challenges,” and “anxiety/stress/fear.” Reporting “no impact” of racism on experiences of VHA health care was salient across race and sex; however, reports of race-related unprofessional treatment and active avoidance of race-related conflict differed by race (present among Black and not White participants). Experiences of interpersonal interactions also diverged. “Impersonal/cursory” telehealth experiences and the need for “more personal/attentive” care were salient among women and Black participants, but not men or White participants, who associated VHA care with courtesy and respect.Conclusions and RelevanceIn this qualitative freelist study of veteran experiences, divergent experiences of interpersonal care by race and sex provided insights for improving equitable, patient-centered VHA care. Future research and interventions could focus on identifying differences across broader categories both within and beyond race and sex and bolstering efforts to improve respect and personalized care to diverse veteran populations.
Sublingual Edaravone Dexborneol for the Treatment of Acute Ischemic Stroke
Authors: Fu Yu , Wang Anxin , Tang Renhong , Li Shuya , Tian Xue , Xia Xue , Ren Jinsheng , Yang Shibao , Chen Rong , Zhu Shunwei , Feng Xiaofei , Yao Jinliang , Wei Yan , Dong Xueshuang , Ling Yun , Yi Fei , Deng Qian , Guo Cunju , Sui Yi , Han Shugen , Wen Guoqiang , Li Chuanling , Dong Aiqin , Sun Xin , Wang Zhimin , Shi Xueying , Liu Bo , Fan Dongsheng 
Published: February 2024

ImportanceSublingual edaravone dexborneol, which can rapidly diffuse and be absorbed through the oral mucosa after sublingual exposure, is a multitarget brain cytoprotection composed of antioxidant and anti-inflammatory ingredients edaravone and dexborneol.ObjectiveTo investigate the efficacy and safety of sublingual edaravone dexborneol on 90-day functional outcome in patients with acute ischemic stroke (AIS).Design, Setting, and ParticipantsThis was a double-blind, placebo-controlled, multicenter, parallel-group, phase 3 randomized clinical trial conducted from June 28, 2021, to August 10, 2022, with 90-day follow-up. Participants were recruited from 33 centers in China. Patients randomly assigned to treatment groups were aged 18 to 80 years and had a National Institutes of Health Stroke Scale score between 6 and 20, a total motor deficit score of the upper and lower limbs of 2 or greater, a clinically diagnosed AIS symptom within 48 hours, and a modified Rankin Scale (mRS) score of 1 or less before stroke. Patients who did not meet the eligibility criteria or declined to participate were excluded.InterventionPatients were assigned, in a 1:1 ratio, to receive sublingual edaravone dexborneol (edaravone, 30 mg; dexborneol, 6 mg) or placebo (edaravone, 0 mg; dexborneol, 60 μg) twice daily for 14 days and were followed up until 90 days.Main Outcomes and MeasuresThe primary efficacy outcome was the proportion of patients with mRS score of 1 or less on day 90 after randomization.ResultsOf 956 patients, 42 were excluded. A total of 914 patients (median [IQR] age, 64.0 [56.0-70.0] years; 608 male [66.5%]) were randomly allocated to the edaravone dexborneol group (450 [49.2%]) or placebo group (464 [50.8%]). The edaravone dexborneol group showed a significantly higher proportion of patients experiencing good functional outcomes on day 90 after randomization compared with the placebo group (290 [64.4%] vs 254 [54.7%]; risk difference, 9.70%; 95% CI, 3.37%-16.03%; odds ratio, 1.50; 95% CI, 1.15-1.95, P = .003). The rate of adverse events was similar between the 2 groups (89.8% [405 of 450] vs 90.1% [418 of 464]).Conclusion and RelevanceAmong patients with AIS within 48 hours, sublingual edaravone dexborneol could improve the proportion of those achieving a favorable functional outcome at 90 days compared with placebo.Trial RegistrationClinicalTrials.gov Identifier: NCT04950920
High‐Throughput Ammonia Production from Nitrate Using Liquid Metal Synthesized Bismuth Nano‐Catalyst
Authors: Nazari Sahar , Sun Jing , Baharfar Mahroo , Poulin Philippe , Kalantar‐Zadeh Kourosh , Jalili Ali (Rouhollah) , Esrafilzadeh Dorna 
Published: February 2024

AbstractThe implementation of renewable energy sources to electrify ammonia (NH3) production is identified as a critical approach for achieving successful decarburization in the pursuit of a more sustainable future. A liquid metal‐based method is presented for synthesizing bismuth (Bi) nano‐electrocatalysts, enabling efficient and sustainable ammonia production via nitrate electroreduction. Bi‐metal precipitated from a gallium liquid metal alloy yields solution‐processable Bi and oxide with controllable nanostructures such as nanosheets, nanotubes, and nanoparticles. Combining Bi nano‐electrocatalysts and graphene liquid crystals creates self‐assembling layered electrocatalytic systems. Integrating 3D printing technology allows for precise control over the geometry, microporosity, and number of deposited layers of the electrocatalytic scaffold electrode, resulting in improved mass transport properties, durability, and the prevention of catalyst detachment. Consequently, the ammonia production rate reaches 400 nmol s−1 cm−2, with a Faradaic efficiency of over 90% and current densities exceeding 350 mA cm−2. These numbers indicate the excellent scalability potential of the proposed electrocatalytic system.
Uncovering Synergistic Effects of Electrode/Electrolyte Toward Concerted Cathodic Structure Stabilization for Superior‐Performance Aqueous Zn‐δ‐MnO2 Battery
Authors: Qiao Haohui , Zhu Xiaodong , Li Xuanyang , Wang Yuan , Ye Chuming , Ma Longli , Shen Jianfeng , Ye Mingxin 
Published: February 2024

AbstractRechargeable aqueous Zn‐δ‐MnO2 batteries, featuring high safety, high theoretical capacity, and low cost, have emerged as promising candidates for grid‐scale energy storage systems. Nevertheless, the severe cathodic structural degradation greatly hinders its further commercial application. Herein, a facile coupling engineering strategy, employing the Ti3C2Tx MXene skeleton coupled with electrolyte additive K2SO4 to reinforce the structural stability of the δ‐MnO2 cathode is proposed. Notably, the designed K‐birnessite δ‐MnO2/Ti3C2Tx composite cathode (KMO/Ti3C2) coupled with K2SO4 electrolyte additive exhibits unique electrode/electrolyte synergistic effects on inhibiting the cathodic structural collapse and promoting the Mn2+ electrodeposition. Meanwhile, the plating/stripping reversibility of the Zn anode is considerably improved by manipulating the formation of zinc dendrites. Consequently, the Zn//KMO/Ti3C2 battery achieves the remarkable specific capacity of 502.2 mAh g−1 at 0.3 A g−1 and 371.1 mAh g−1 at 2.0 A g−1. Furthermore, after 9500 cycles at a high current density of 10 A g−1, the capacity retention reaches 93.3%. Besides, the dendrite‐free Zn anode delivers excellent cycling stability (over 4800 h at 0.2 mA cm−2) and high coulombic efficiency (99.9% after 2300 cycles). The synergistic effect of electrode/electrolyte provides distinctive insights into the structural stabilization of the manganese‐based cathode to improve the overall performance of batteries.