bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kernresonanz‐Untersuchungen zur Diffusion von Fremdionen in AgBr
Authors: Becker K. D. , Richtering H. 
Published: October 2023

AbstractIn festem AgBr wurde der Einfluß von Zusätzen an Alkali‐, Cu+ ‐, Cd2+ ‐ und Mg2+ ‐lonen auf die Linienbreite der Br‐Kernresonanzen zwischen ‐ 100°C und dem Schmelzpunkt untersucht. In allen Fällen, außer für CsBr‐Zusatz, treten ausgeprägte Breitenmaxima auf. Sie sind auf eine durch den Platzwechsel der Fremdionen verursachte Spin‐Gitter‐Relaxation zurückzuführen. Eine Beschreibung mit der Reifschen Theorie der dynamischen Quadrupolwechselwirkung zwischen den Br‐Kernen und diffundierenden Überschußladungen ist auch für die einwertigen Zusätze möglich. Sie liefert Absolutwert und Temperaturabhängigkeit der mittleren Sprungfrequenzen. Alle Fremdionen außer Cu+ springen über Kationen‐Leerstellen und zeigen untereinander eine überraschende Ähnlichkeit in der Platzwechselfrequenz und in der Stärke der Quadrupol‐Wechselwirkung. Die Aktivierungsenergien für den Platzwechsel von Li+, Na+, K+, Mg2+ und Cd2+ in AgBr betragen 1,0, 1,3, 1,1, 1,35 und 1, 45 eV.
Fluoride‐Fluoride Association in Aqueous Solution from F19 Nuclear Magnetic Relaxation Data
Authors: Hertz H. G. , Rädle C. 
Published: October 2023

AbstractExperimental F19 nuclear magnetic relaxation rates in alkali metal fluoride solutions in D2O are reported as a function of the concentration. In these solutions a remarkable excess relaxation effect appears which can only be due to the strong magnetic dipole‐dipole interaction between two F19 nuclei in relatively close contact. The experimental data may be explained in terms of a F− F− pair distribution function which is characterized by the parameters: Closest F− F− separation a = 3 A; first coordination number of F− with respect to F−: na = 1.
Formation and Reactions of Long Lived Xanthene Dye Radicals. II. Photochemical Reduction of Rhodamine‐B and Fluoresceïn Derivatives
Authors: Krüger U. , Memming R. 
Published: October 2023

AbstractIt is reported about the formation and reactions of the semireduced species of methylated fluoresceïn, rhodamine‐B and pyronine. ESR‐measurements have shown that the semireduced methylated fluoresceïn in acetonitrile formed by a reaction between the dye triplet and the leuco‐dye, is a triphenylmethyl type radical. It disappears via a disproportionation reaction, the trimethylated radicals having lifetimes of several months. Oxidation by oxygen leads to the formation of a dye peroxide. The results obtaines with rhodamine‐B are similar to those obtaines with fluoresceïn in aqueous solution (see part I), however, photochemical reactions were only observed after excitation into a higher energy level of rhodamine‐B. These results are compared with those obtained with pyronine.
Studies of Ultrafast Chemical and Physical Processes with Picosecond Lasers
Authors: Eisenthal K. B. 
Published: October 2023

AbstractPicosecond studies of the dynamics of the cage effect in the recombination of iodine atoms and collision induced predissociation of I2 are reported. Also studies of intermolecular energy transfer on the picosecond time scale and comparison with theory are presented. Lastly, the dynamics of excited state charge transfer complex formation and comparison with theory is presented.
Modulation Spectroscopy
Authors: Giinthard H. H. 
Published: October 2023

AbstractAfter a brief review of modulation methods in chemistry experiments with modulated excitation in the field like infrared (MEIR) and electron spin resonance (MESR) are discussed. These will be discussed in the frame work of a simple Jablonski diagram comprising ground and first excited singlet, first excitet triplet and irreversible photo chemical transformations; for the latter arbitrary first order systems may be assumed. Basing on approximate solutions of the kinetic equations it is shown that the modulated component of the populations of the particles of the system follow basically simple amplitude‐phase relation ships, which are analogs of the well known Bode relations for linear electrical networks. MEIR and MESR studies of the photooxidation of polyhydroxy benzenes show that both ground state, hydrogen bond associated dimers and photo radicals follow simple amplitude‐phase dependence on modulation frequency from which information about mechanism and reaction rate constants may be derived. Finally a brief discussion of the general problem of the reconstruction of linear chemical systems from amplitude‐phase measurements is given.
Hadamard‐NMR‐Spektroskopie
Authors: Ziessow D. , Blümich B. 
Published: October 2023

AbstractImpulssequenzen mit pseudo‐stochastisch schwankender Amplitude oder Phase als breitbandige NMR‐Anregung haben den Vorteil einer gleichmäßig über die Beobachtungszeit verteilten Anregungsleistung von kleiner Spitzenleistung. Von Nachteil war bisher die gegenüber der Impulsmethode umständlichere digitale Verarbeitung der Meßdaten. Es wird gezeigt, daß dieser Nachteil durch Anwendung der Hadamardtransformation vermieden werden kann, die in außerordentlich kurzer Zeit die Korrelation von Anregung und Signal in der Zeitdomäne ermöglicht. Die berechnete Funktion ähnelt dem FID‐Signal und dient als Eingang für die Fouriertransformation nach dem FF‐T‐Kalkül. Methodische Aspekte wie Impulsbreite und ‐stärke, Sättigung und der Einfluß der Relaxationszeiten werden durch numerische Lösung der Blochschen Gleichungen behandelt.
Nuclear Spin Polarization from Triplet States in Solution
Authors: Bargon Joachim , Seifert K. G. 
Published: October 2023

AbstractProton and fluorine spin polarizations in solutions of optically excited p‐benzoquinones are shown to stem from the triplet states of the quinones. The phenomenon is analogous to the Optical Nuclear Polarization (ONP) effect in solids. ONP in solution is detected only if the relaxation processes among the triplet sublevels cannot destroy the polarization during the lifetimes of the triplets totally. The quinones are unique in having extremely short lived triplets. Therefore, ONP can be detected in their ground states by high resolution nmr, which allows to map out the electron distribution of the triplet states.
Ein neuartiges Phasenfluorometer
Authors: Resewitz E.‐P. , Lippert E. 
Published: October 2023

AbstractAm Iwan N. Stranski‐Institut wurde eine Apparatur entwickelt, die nach dem Prinzip des Phasenfluorometers das Messen von Fluores‐zenzabklingzeiten gestattet. Im Bereich der höchsten Modulationsfrequenz hat die Apparatur eine Auflösung von 0,2° und gestattet die Messung von Abklingzeiten von etwa 0,2 bis 200 ns.Die Anregung der Fluoreszenz erfolgt mit der Strahlung einer Hg‐Höchstdrucklampe, die mit einer Pockels‐Zelle moduliert wird. Der Phasenvergleich des Anregungslichts mit dem Fluoreszenzlicht geschieht in einem Photovervielfacher mit Steuergitter. Die Phasenlage der Signale wird automatisch digital kompensiert und angezeigt.Das Gerät ist einfach zu bedienen und erlaubt eine maximale Genauigkeit von 0,1°. Es ist daher besonders geeignet für die Messung der Konzentrations‐, Lösungsmittel‐ und Temperatur‐Abhängigkeit von Fluoreszenzabklingzeiten. Erste Messungen an bekannten Substanzen haben die Funktionstüchtigkeit des Gerätes bereits bestätigt.
Ein Verfahren zur Herstellung von Schichten reproduzierbarer Dicke auf Trägern
Authors: Hofmann K. P. , Zundel G. 
Published: October 2023

AbstractHydratisierte Proben für die IR‐Spektroskopie lassen sich herstellen, indem man eine Lösung der zu untersuchenden Substanz auf einem geeigneten waagrechten Träger bei definiertem Druck eindampfen läßt. Für quantitative Absorptionsmessungen ist die Dicke der so erhaltenen Schichten nicht genügend reproduzierbar, weil die Kohäsion der Lösung und ihre Adhäsion am Rand des Trägers von einem Parameter der Messung, der variiert wird, abhängen kann.Um die erforderliche Reproduzierbarkeit der Schichtdicke von ±1% zu erhalten, gingen wir davon aus, daß eine gegenüber der Schwerkraft wesentlich erhöhte Kraftwirkung auf die eintrocknende Lösung diese störenden Einflüsse zum Verschwinden bringen würde. Dies führte zu einer Anordnung, die anstelle eines Zentrifugenbechers in handelsüblichen Swing‐out‐Rotoren aufgehängt werden kann. Diese Anordnung wird beschrieben. Insbesondere wird gezeigt, wie der Dampfdruck eingestellt wird, und wie die Justierung des Probenträgers mit der erforderlichen hohen Genauigkeit auf einfache Weise möglich ist.
Schweratom‐induzierte Fluoreszenzlöschung und Termschema von mehrkernigen aromatischen Kohlenwasserstoffen und Heterocyclen
Authors: Dreeskamp H. , Koch E. , Zander M. 
Published: October 2023

AbstractAn 20 mehrkernigen aromatischen Kohlenwasserstoffen und Heterocyclen wurden Fluoreszenzlöschversuche unter der Wirkung von 1‐Jodpropan als Löschsubstanz durchgeführt und die bimolekularen Geschwindigkeitskonstanten der Fluoreszenzlöschung in benzolischer Lösung bei Raumtemperatur gemessen. Die bimolekularen Geschwindigkeitskonstanten überdecken einen Bereich von mehr als 4 Zehnerpotenzen. Es wird gezeigt, daß die Geschwindigkeitskonstanten der Löschung exponentiell mit der Energiedifferenz der interkombinierenden Terme abnehmen, wobei diese Energiedifferenz gegeben ist durch den Abstand vom fluoreszierenden S1‐Zustand zum nächst niedrigeren Triplettzustand. Die Beobachtung, daß die Geschwindigkeitskonstante der Löschung beim Pyren‐Excimeren kleiner als die des Pyren‐Monomeren ist, wird durch die stark unterschiedliche Verschiebung von Singlett‐ und Triplett‐Termen bei der Excimeren‐Bildung gedeutet.
Massenspektrometrische Untersuchungen an Silberhalogeniden III: Silberbromid und Silberjodid
Authors: Bernauer O. , Weil K. G. 
Published: October 2023

AbstractBei der Elektronenstoßionisation von Silberbromiddampf werden die folgenden Ionen gebildet (in Klammern die Auftrittspotentiale): Ag+ (11,3 eV), AgBr+ (9,1 eV), Ag2+, Ag3+ Ag2Br+, (11,9 eV), Ag3Br3+, Ag2Br2+, Ag3Br2+ (9,8 eV), Ag3Br3+ (9,6 eV), Ag4Br3+. Aus den Ionisierungskurven, den Auftrittspotentialen, der Abhängigkeit des Massenspektrums von der Elektronenenergie und der Temperaturabhängigkeit des Massenspektrums wird geschlossen, daß der Dampf AgBr‐ und Ag3Br3‐Moleküle enthält. Für die Verdampfungsenthalpien von Monomer‐ und Trimeranteil ergeben sich folgende Werte:
equation image
Daraus ergibt sich für die Trimerisierungsreaktion in der Gasphase
equation image
Mit Hilfe eines thermodynamischen Kreisprozesses ergibt sich eine Dissoziationsenthalpie für AgBr(gas) von 272 kJ/mol. Aus den Auftrittspotentialen erhält man für die Dissoziationsenergie von AgBr+ einen Wert von 212,3 kJ/mol.Silberjodid keine Temperaturabhängigkeit des Massenspektrums gemessen werden.Sowohl für Silberbromid als auch für Silberjodid wird ein Zerfallsschema Für die Ionen abgeleitet und diskutiert.
Das Valenzkraftfeld des Dimethylnitrosamins
Authors: Rademacher P. , Lüttke W. 
Published: October 2023

AbstractDas Valenzkraftfeld des Dimethylnitrosamins wurde mit den Schwingungsfrequenzen der sieben isotopen Moleküle (CH3)2NNO, (CD3)2NNO, (CH3)2NN18O, (CH3)2N15NO, (CH3)215NNO, CD3(CH3)NNO und CH3)NNO bestimmt. Die Normalschwingungen und die Verteilung der potentiellen Energie wurden berechnet. Die Kraftkonstanten zeigen eine starke Konjugation zwischen NN‐ und NO‐Bindung an. Die für die wichtigeren Abstände berechneten mittleren Schwingungsamplituden stimmen gut mit den Ergebnissen einer Elektronenbeugungs‐Untersuchung überein.
Sensor‐integrated brain‐on‐a‐chip platforms: Improving the predictive validity in neurodegenerative research
Authors: Spitz Sarah , Schobesberger Silvia , Brandauer Konstanze , Ertl Peter 
Published: October 2023

AbstractAffecting millions of individuals worldwide, neurodegenerative diseases (NDDs) pose a significant and growing health concern in people over the age of 60 years. Contributing to this trend are the steady increase in the aging population coupled with a persistent lack of disease‐altering treatment strategies targeting NDDs. The absence of efficient therapeutics can be attributed to high failure rates in clinical trials and the ineptness of animal models in preceding preclinical studies. To that end, in recent years, significant research effort has been dedicated to the development of human cell‐based preclinical disease models characterized by a higher degree of predictive validity. However, a key requirement of any in vitro model constitutes the precise knowledge and replication of the target tissues' (patho‐)physiological microenvironment. Herein, microphysiological systems have demonstrated superiority over conventional static 2D/3D in vitro cell culture systems, as they allow for the emulation and continuous monitoring of the onset, progression, and remission of disease‐associated phenotypes. This review provides an overview of recent advances in the field of NDD research using organ‐on‐a‐chip platforms. Specific focus is directed toward non‐invasive sensing strategies encompassing electrical, electrochemical, and optical sensors. Additionally, promising on‐ and integrable off‐chip sensing strategies targeting key analytes in NDDs will be presented and discussed in detail.
Evaluation of the safety and efficiency of cytotoxic T cell therapy sensitized by tumor antigens original from T‐ALL‐iPSC in vivo
Authors: Li Weiran , Zhou Meiling , Wang Lu , Huang Liying , Chen Xuemei , Sun Xizhuo , Liu Tao 
Published: October 2023

AbstractBackgroundSince RNA sequencing has shown that induced pluripotent stem cells (iPSCs) share a common antigen profile with tumor cells, cancer vaccines that focus on iPSCs have made promising progress in recent years. Previously, we showed that iPSCs derived from leukemic cells of patients with primary T cell acute lymphoblastic leukemia (T‐ALL) have a gene expression profile similar to that of T‐ALL cell lines.MethodsMice with T‐ALL were treated with dendritic and T (DC‐T) cells loaded with intact and complete antigens from T‐ALL‐derived iPSCs (T‐ALL‐iPSCs). We evaluated the safety and antitumor efficiency of autologous tumor‐derived iPSC antigens by flow cytometry, cytokine release assay, acute toxicity experiments, long‐term toxicity experiments, and other methods.ResultsOur results indicate that complete tumor antigens from T‐ALL‐iPSCs could inhibit the growth of inoculated tumors in immunocompromised mice without causing acute and long‐term toxicity.ConclusionT‐ALL‐iPSC‐based treatment is safe and can be used as a potential strategy for leukemia immunotherapy.
Randomized clinical trial of abluminus DES+ sirolimus‐eluting stent versus everolimus‐eluting DES for percutaneous coronary intervention in patients with diabetes mellitus: An optical coherence tomography study
Authors: Maurina Matteo , Chiarito Mauro , Leone Pier Pasquale , Testa Luca , Montorfano Matteo , Reimers Bernhard , Esposito Giovanni , Monti Francesco , Ferrario Maurizio , Latib Azeem , Colombo Antonio 
Published: October 2023

AbstractBackgroundDiabetic patients are at higher risk of recurrent adverse events following percutaneous coronary intervention (PCI) than the nondiabetics. Despite the introduction of new generation drug‐eluting stents, their efficacy in the diabetics is still limited.AimsTo evaluate the efficacy of the Abluminus DES+ biodegradable polymer sirolimus‐eluting stent in reducing neointimal hyperplasia in diabetic patients, compared to a durable polymer everolimus‐eluting stent (DP‐EES).MethodsA total of 131 patients with diabetes and coronary artery disease were enrolled in six Italian centers and randomized in a 2:1 fashion to PCI with Abluminus DES+ or DP‐EES: 85 were assigned to Abluminus DES+ and 46 to DP‐EES. The primary endpoint was optimal coherence tomography (OCT)‐derived neointimal volume at 9–12 months. Secondary endpoints included OCT‐derived neointimal area, neointimal volume obstruction and adverse clinical events.ResultsThe primary endpoint, neointimal volume, did not differ between Abluminus DES+ and DP‐EES (29.11 ± 18.90 mm3 vs. 25.48 ± 17.04 mm3, p = 0.40) at 9–12‐month follow‐up. This finding remained consistent after weighing for the sum of stents lengths (1.14 ± 0.68 mm3 vs. 0.99 ± 0.74 mm3 for Abluminus DES+ and DP‐EES, respectively, p = 0.38). Similarly, other OCT‐derived and clinical secondary endpoints did not significantly differ between the two groups. Rate of target lesion failure was high in both groups (21.2% for Abluminus DES+ and 19.6% for DP‐EES).ConclusionsThis preliminary study failed to demonstrate the superiority of the Abluminus DES+ over the DP‐EES in diabetic patients in terms of neointimal proliferation.
Transseptal puncture in left atrial appendage closure guided by 3D printing and multiplanar CT reconstruction
Authors: Hozman Marek , Herman Dalibor , Zemanek David , Fiser Ondrej , Vrba David , Poloczek Martin , Varvarovsky Ivo , Obona Peter , Pokorny Tomas , Osmancik Pavel 
Published: October 2023

AbstractBackgroundThe presented study investigates the application of bi‐arterial 3D printed models to guide transseptal puncture (TSP) in left atrial appendage closure (LAAC).AimsThe objectives are to (1) test the feasibility of 3D printing (3DP) for TSP guidance, (2) analyse the distribution of the optimal TSP locations, and (3) define a CT‐derived 2D parameter suitable for predicting the optimal TSP locations.MethodsPreprocedural planning included multiplanar CT reconstruction, 3D segmentation, and 3DP. TSP was preprocedurally simulated in vitro at six defined sites. Based on the position of the sheath, TSP sites were classified as optimal, suboptimal, or nonoptimal. The aim was to target the TSP in the recommended position during the procedure. Procedure progress was assessed post hoc by the operator.ResultsOf 68 screened patients, 60 patients in five centers (mean age of 74.68 ± 7.64 years, 71.66% males) were prospectively analyzed (3DP failed in one case, and seven patients did not finally undergo the procedure). In 55 patients (91.66%), TSP was performed in the optimal location as recommended by the 3DP. The optimal locations for TSP were postero‐inferior in 45.3%, mid‐inferior in 45.3%, and antero‐inferior in 37.7%, with a mean number of optimal segments of 1.34 ± 0.51 per patient. When the optimal TSP location was achieved, the procedure was considered difficult in only two (3.6%) patients (but in both due to complicated LAA anatomy). Comparing anterior versus posterior TSP in 2D CCT, two parameters differed significantly: (1) the angle supplementary to the LAA ostium and the interatrial septum angle (160.83° ± 9.42° vs. 146.49° ± 8.67°;p = 0.001), and (2) the angle between the LAA ostium and the mitral annulus (95.02° ± 3.73° vs. 107.38° ± 6.76°;p < 0.001), both in the sagittal plane.ConclusionsIn vitro TSP simulation accurately determined the optimal TSP locations for LAAC and facilitated the procedure. More than one‐third of the optimal TSP sites were anterior.
A novel method of prosthetic leaflet modification to enable transcatheter mitral valve‐in‐valve replacement
Authors: Spilias Nikolaos , Miyasaka Rhonda , Kapadia Samir R. , Krishnaswamy Amar 
Published: October 2023

AbstractLeft ventricular outflow tract (LVOT) obstruction from the displaced prosthetic anterior mitral leaflet is a life‐threatening complication that can occur during valve‐in‐valve (ViV) transcatheter mitral valve replacement (TMVR). Laceration of the anterior mitral leaflet to prevent outflow obstruction is a well‐established transcatheter technique to mitigate the risk of LVOT obstruction in high‐risk anatomies. In this report, we present a novel transseptal technique of prosthetic leaflet modification to prevent LVOT obstruction during ViV TMVR.
Transapical concomitant transseptal transcatheter closure of a giant mitral paravalvular leak under three‐dimensional printing guidance
Authors: Jin Ping , Wang Yiwei , Liu Yang , Yang Jian 
Published: October 2023

AbstractA mitral paravalvular leak (PVL) is a significant complication of surgical valve replacement that has a profound impact on the health and survival of patients. Transcatheter closure of PVL has emerged as a promising treatment option. We present the case of a 65‐year‐old patient who experienced exertional dyspnea, chest tightness, and peripheral edema (New York Heart Association functional class Ⅵ) following surgical aortic and mitral valve replacement. Echocardiography and computed tomography performed on admission revealed a giant mitral PVL (1 bundle, volume 25.0 mL, area 13.0 cm²). Due to the patient's high surgical risk and complex anatomical characteristics, a patient‐specific three‐dimensional printed model was utilized to visualize anatomical structures and simulate the main procedures. After careful consideration, the surgical team opted to perform transcatheter closure of the giant mitral PVL via a transapical concomitant transseptal approach using two carefully selected devices of different sizes (14‐mm and 16‐mm Amplatzer Vascular Plug II). The procedure was carried out successfully. During the 1‐month follow‐up, the patient remained asymptomatic (New York Heart Association functional class Ⅰ). Transcatheter closure of a giant and complex mitral PVL utilizing three‐dimensional printing guidance has proven to be a feasible approach.
The relation of polymer structure of stent used in patients with acute coronary syndrome revascularized by stent implantation with long‐term cardiovascular events
Authors: Yaylak Barış , Polat Fuat , Onuk Tolga , Akyüz Şükrü , Çalık Ali Nazmi , Çetin Mustafa , Eren Semih , Mollaalioğlu Feyza , Kolak Zeynep , Durak Furkan , Dayı Şennur Ünal 
Published: October 2023

AbstractIntroductionDrug‐eluting stents (DES) have revolutionized percutaneous coronary intervention (PCI) by improving event‐free survival compared to older stent designs. However, early‐generation DES with polymer matrixes have raised concerns regarding late stent thrombosis due to delayed vascular healing. To address these issues, biologically bioabsorbable polymer drug‐eluting stents (BP‐DES) and polymer‐free drug‐eluting stents (PF‐DES) have been developed.AimThe aim of the present study is to evaluate and compare the long‐term effects of different stent platforms in patients with acute coronary syndrome (ACS) undergoing PCI.Material and MethodsWe conducted a retrospective, observational study involving 1192 ACS patients who underwent urgent PCI. Patients were treated with thin‐ strut DP‐DES, ultra‐thin strut BP‐DES, or thin‐strut PF‐DES. The primary endpoint was a composite of cardiac death, target vessel myocardial infarction (TVMI), and clinically driven target lesion revascularization (CITLR) at 12 months and 4 years.ResultsThe baseline demographics and clinical characteristics of patients in the three stent subgroups were similar. No significant differences were observed in target lesion failure (TLF), cardiac mortality, TVMI, and stent thrombosis (ST) rates among the three subgroups at both 12 months and 4 years. However, beyond the first year, the rate of CITLR was significantly lower in the ultra‐thin strut BP‐DES subgroup compared to thin‐strut DP‐DES, suggesting potential long‐term advantages of ultra‐thin strut BP‐DES. Additionally, both ultra‐thin strut BP‐DES and thin‐strut PF‐DES demonstrated lower ST rates after the first year compared to thin‐strut DP‐DES.ConclusionOur study highlights the potential advantages of ultra‐thin strut BP‐DES in reducing CITLR rates in the long term, and both ultra‐thin strut BP‐DES and thin‐strut PF‐DES demonstrate lower rates of ST beyond the first year compared to thin‐strut DP‐DES. However, no significant differences were observed in overall TLF, cardiac mortality and TVMI rates among the three stent subgroups at both 12 months and 4 years.