bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bestimmung der kritischen Exponenten für das binäre System Anilin‐Cyclohexan bei drei verschiedenen Konzentrationen in der Nähe der kritischen Konzentration durch Lichtstreumessung
Authors: Jaeckel K. , Majer U. 
Published: October 2023

AbstractAus Messungen des Streulichtes am System Anilin‐Cyclohexan können wir folgern, daß die von Calmettes et al. [22] in einem Temperatur‐intervall 0,2 ≦ Δ T = T ‐ Tc ≦ 2°C oberhalb des kritischen Punktes Tc gefundenen kritischen Exponenten ν und γ mit unseren Exponenten. die in einem Temperaturintervall 0,003 ≤ ΔT ≤ 0,3°C vermessen wurden, innerhalb der Fehlergrenzen übereinstimmen. Darüber hinaus wird durch unsere Messungen bei drei verschiedenen Konzentrationen in der Nähe der kritischen Konzentration die Pseudospinodal‐Theorie von Chu, Schoenes und Fisher bestätigt.
Röntgenstrukturuntersuchung des flüssigen Acetonitrils
Authors: Kratochwill Alwin , Weidner Jörg U. , Zimmermann Herbert 
Published: October 2023

AbstractAus der experimentellen Intensitätsverteilung der Röntgenstreustrahlung wurden die radiale Elektronendichteverteilung und die reduzierte Intensität des flüssigen Acetonitrils bei 20 °C ermittelt. Letztere läßt sich unter Verwendung eines genäherten Molekülmodells in einen intra‐und intermolekularen Anteil zerlegen. Durch Optimierungsrechnungen wurden daraus die Struktur des Moleküls und die Nahordnung in flüssiger Phase ermittelt.Für das Molekül ergaben sich: C ‐ C = 1,465 Å, C ‐ N = 1,153 Å. Die mittleren Schwingungsamplituden waren etwas größer als solche, die aus IR‐Daten mit Normalkoordinaten berechnet wurden.Die Nahordnung der Moleküle in flüssiger Phase haben wir an Hand verschiedener, schrittweise verfeinerter Strukturmodelle untersucht. Beste Übereinstimmung mit dem Experiment ergab sich bei einem Flüssigkeitsmodell mit Korrelationsclustern. Innerhalb der Cluster liegt eine Struktur vor, die durch ein Korrelationsgitter beschrieben wird. Die Einheitszelle ist rhombisch und enthält acht Moleküle, deren Dipolachsen entweder parallel oder antiparallel zur a‐Achse liegen. Die Besetzung der Gitterplätze beträgt 95%. Die Abnahme der Lage‐ und Orientierungskorrelation mit steigendem Molekülabstand wurde berücksichtigt.Der Einfluß der räumlichen Begrenzung der Cluster auf die Radialverteilung läßt sich durch eine Gewichtsfunktion H(r) beschreiben. H(r) charakterisiert die Größe des Clusters und die Korrelation der Moleküle innerhalb desselben. Wie die Optimierungsrechnungen ergaben, besteht vollständige Lage‐ und Orientierungskorrelation für die vier Moleküle der ersten Koordinationssphäre um ein Zentralmolekül. Der mittlere Zentrenabstand zum Zentralmolekül beträgt 3,8 Å. Der Clusterdurchmesser ergibt sich zu ca. 11 Å. Dieser Wert entspricht gut einem Clusterdurchmesser von ca. 13 Å, der sich aus der Dipol‐Dipol‐Wechselwirkung abschätzen läßt.Der R‐Faktor für das Strukturmodell beträgt R = 0,077.
Reactions in the Formation of Interstellar Radicals and Molecules
Authors: Harteck P. , Reeves R. R. 
Published: October 2023

AbstractIn this paper the authors have tried to develop a series of reaction mechanisms which seems to explain the occurrence of the observed interstellar molecules in the dark clouds. Special emphasis is given in this paper to the dominant role of H3+ which acts as a proton donor for the formation of ion molecules like COH+, CH+, NH2+, which are very reactive and lead over a series of intermediates to observed species such as: OH, H2CO, NH3, CH, and HCN. As will be seen, there exists a large variety of possible mechanisms for the formation of certain species and it is premature in many cases to decide which of these mechanisms is dominant. We like to emphasize that the formation of these molecules occurs in the gas phase, a fact which does not exclude the formation of molecules on the surface of grains or in ion‐clusters.
Die Dehydratisierung des t‐Butanols an HY‐Zeolith. Untersuchungen mit Hilfe der Feldionenmassenspektrometrie
Authors: Zei M. S. 
Published: October 2023

AbstractIn den Feldionenspektren des t‐Butanols wurden an Au‐ und Pt‐Emittern hauptsächlich die lonen (M‐15)+, d. h. (m/n = 59) und (M‐16)+ beobachtet. Die Intensität der restlichen lonen, wie z. B. (M‐18)+ und (M‐17)+ war vernachlässigbar klein. Alle diese lonenspektren sind praktisch von Temperaturänderungen des Emitters unbeeinflußt. Die lonenspektren beim HY‐Zeolith/Pt‐Emitter unterscheiden sich deutlich von denen der reinen Metallemitter. Neben (M‐15)+ treten hier auch merklich (M‐18)+‐und (M‐17)+‐Ionen auf. Mit abnehmender Feldstärke nimmt die Intensität der lonen (M‐15)+ stark, die der anderen dagegen nur wenig ab, weil nur erstere typische Feldionen sind. Letztere dagegen sind, wie die Temperaturabhängigkeit beweist, durch katalytische Aktivierung gebildet worden. Denn sie können bei genügend hoher Temperatur ( > 300 °C) und kleiner Einsatzfeldstärke sogar intensiver als (M‐15)+ auftreten.
Fall‐off Curves of Unimolecular Reactions
Authors: Troe J. 
Published: October 2023

AbstractFall‐off curves of thermal unimolecular reactions in the strong collision limit and in the general weak collision case are discussed. The fall‐off curves are represented in (k0, k∞)‐reduced form interpolating between both the limiting low pressure and the limiting high pressure rate constants k0 and k∞. In this reduced form fall‐off curves are very insensitive to details of the theory and simplified models can be used. Reduced fall‐off curves are represented in terms of tabulated Kassel integrals; the two Kassel parameters Sk and Bk are expressed in terms of experimental observables like the apparent activation energies in the low and high pressure limit and the collision efficiency. By this procedure some uncertain parts of the theory of unimolecular reactions can be eliminated from the calculation of fall‐off curves.
Nuclear Magnetic Relaxation of Alkali Metal Ions in Aqueous Solutions
Authors: Hertz H. G. , Holz M. , Keller G. , Versmold H. , Yoon C. 
Published: October 2023

AbstractThe paper is introduced by an analysis of the interrelation between the nuclear magnetic relaxation rates of the cations and anions in the same solution when the nuclear quadrupole interaction is the relaxation mechanism. The treatment is based on an electrostatic model. Higher ion‐ion and ion‐water correlations may cause mutual quenching or reinforcement of the relaxation effect at higher ion concentrations. Experimental results for the relaxation rates of Rb85, Rb87, Cs133, Li7, and Na23 in the ionic state are reported Most of the solutions are alkali halide solutions, partly the results regard mixed electrolyte solutions. An interpretation of the results in terms of higher ion‐ion and ion‐water correlations is discussed. A brief consideration of possible “electronic” contributions to the relaxation is also given.
Nahordnung in Flüssigkeiten I. Ein statistisch‐thermodynamisches Flüssigkeitsmodell auf der Basis von Kontaktwahrscheinlichkeiten
Authors: Schröer Wolffram 
Published: October 2023

AbstractEin statistisches Modell der Nahordnung in flüssigen organischen Mischphasen, das einen systematischen Rahmen zur Beschreibung sowohl von thermodynamischen Funktionen als auch von NMR‐Lösungsmittelverschiebungen darstellt, wird vorgestellt. Das Modell ermöglicht es, auf der Basis von Kontaktstellenzahlen, die verschiedenen Atomen und funktionellen Gruppen in Molekülen zugeordnet werden, sowie von den Wechselwirkungsenergien für die Kontakte zwischen den verschiedenen Gruppen die thermodynamischen Funktionen der reinen Stoffe und der Mischungen zu berechnen.
Nahordnung in Flüssigkeiten II. 1H‐ und 13C‐NMR‐Spektroskopische Untersuchungen der Heteroassoziation von Trichloräthylen mit einer starken Base
Authors: Schröer W. , Lippert E. 
Published: October 2023

AbstractEin statistisches Modell [1], das die Nahordnung in Flüssigkeiten mit Hilfe von Kontaktwahrscheinlichkeiten beschreibt, wird zur Analyse von NMR‐Lösungsmittelverschiebungen weiter entwickelt, für die Auswertung von 1H‐ und 13C‐Messungen am ternären System Trichloräthylen/Hexamethyl‐Phosphorsäure‐triamid (HMPT)/Cyclohexan verwendet und mit dem Modell der Assoziationsgleichgewichte in idealen Lösungen verglichen. Für die spezifische Wechselwirkung zwischen dem C2Cl3H‐Wasserstoff und dem PO‐Sauerstoff wird ein Enthalpieinkrement von ΔH = ‐(2,58 ± 0,25) kcal/mol erhalten. Die Assoziatverschiebungen der Kerne der CH‐Bindung betragen δH = 2,07 ppm und δ = 5,11 ppm, und zwar beide nach kleinem Feld.
Estimated Distributions of Electronic Redox Levels in aq/eaq−, Haq+/Haq and Some Other Systems
Authors: Henglein A. 
Published: October 2023

AbstractA crude estimate of the distributions of occupied and unoccupied electronic levels of the redox systems aq/eaq− (aq: water traps) and Haq−/Haq is made using known optical and thermodynamic data of the species involved. The distribution of unoccupied levels in Haq−/Haq is thought to be rather narrow, while that of the occupied levels is wide. Under these circumstances, the hydrated electron may be expected to react with Haq− via tunneling with a nearly diffusion controlled rate. The reaction of the mobile electron with Haq− is expected to be rather slow because of the low density of unoccupied states of the system Haq−/Haq at the energy level of emobile−. Similar considerations were applied to the redox systems Haq/Haq− and OHaq/OHaq−. In both cases, the distribution of unoccupied levels is very broad. The polarograms of H and OH which have recently been measured in the 10−5 s range may be understood in terms of these estimated distribution functions. Ions of high negative redox potentials such as Mgaq2+ are expected to be more reactive towards mobile than towards hydrated electrons.
Research award: Interactive information retrieval
Authors: Kelly Diane 
Published: October 2023

EDITOR'S SUMMARYDiane Kelly progressed from having no idea of information science as a field of inquiry to receiving the 2014 ASIS&T Research Award for her outstanding contributions to the field. Through an early library science course, Kelly met information science scholars and soon started her journey researching interactive information retrieval, search behavior, search interfaces and research methods. She became one of the “user study people” when few in the information retrieval community thought about the search process. Kelly appreciates starting her studies before Google's search box and blinking cursor became pervasive and realizing the wealth of ideas predating Google that are worthy of renewed investigation. She expressed concern that information seeking may become passive receipt of preformed information. In her further research, Kelly hopes to shed more light on the process of search and success metrics.
Passive Drag Reduction Technologies
Authors: Kouser Taiba , Zulfiqar Hina , Misbah Misbah , Alhems Luai Muhammad 
Published: October 2023

AbstractThe developments and involved factors of mature passive drag reduction technologies, i.e., compliant coating, superhydrophobic surfaces, and epoxy coating, are reviewed. Alterations in critical Reynolds number are observed in the presence of passive drag reduction technologies. With the advancement in technology, numerical approaches are introduced to lower the cost and achieve better understanding of physical phenomena such as lowering energy, flow control, designing the surfaces of materials, and so on. Experimental results as well as numerical results are stated. The effects of factors like wetting, contact angle, contact angle hysteresis, roughness, pot life, and coating aging responsible for drag reduction are also briefly presented with numerical and experimental perspective analyses.
Regioselectivity for the Rh(I)‐catalyzed Annulation of 1,2,3‐Thiadiazoles with Alkynes: Experimental and Computational Analysis Reveal the Surprising Role of the Alkyne Substituent
Authors: Reza Tasiana , Tokareva Marina A. , Dobson Natalie K. , Shanahan Alexandra L. , Sheather Kyle , Richardson Christopher , Keaveney Sinead T. 
Published: October 2023

AbstractThe Rh(I)‐catalyzed denitrogenative annulation reactions of 1,2,3‐thiadiazoles are a new direct approach to synthesizing densely functionalized heterocycles. The synthesis of multisubstituted thiophenes is possible using this methodology, however the difficulty to predict which regioisomer will form is a current limitation. In this current work, systematic computational and experimental studies were performed addressing how the terminal alkyne substituent effects regioselectivity. The data revealed that the electronic and steric properties of the alkyne substituent effects regioselectivity, including whether the group is aryl or alkyl. The insight gained from this study has allowed the development of a framework for predicting regioselectivity for the Rh(I)‐catalyzed denitrogenative transannulation of 1,2,3‐thiadiazoles with terminal alkynes.
Differential diagnosis between urticarial vasculitis and chronic spontaneous urticaria: An international Delphi survey
Authors: Krause Karoline , Bonnekoh Hanna , Jelden‐Thurm Jannis , Asero Riccardo , Gimenez‐Arnau Ana Maria , Cardoso José C. , Grattan Clive , Kocatürk Emek , Lippert Undine , Maurer Marcus , Metz Martin , Staubach Petra , Goncalo Margarida , Kolkhir Pavel 
Published: October 2023

AbstractBackgroundUrticarial vasculitis (UV) should be differentiated from chronic spontaneous urticaria (CSU) in patients initially presenting with recurrent wheals, although criteria for differential diagnosis remain ill‐defined.ObjectivesTo set the goals, define criteria and unmet needs in UV diagnosis and differential diagnosis with CSU, and explore the possibility of coexistence of both diseases.MethodsThirteen experts experienced in UV research participated in a Delphi survey of European Academy of Allergy and Clinical Immunology taskforce. This Delphi survey involved three rounds of anonymous responses ton = 32 questions with the aim to aggregate the experts' opinions and to achieve consensus. Urticaria specialists (n = 130, most from Urticaria Centers of Reference and Excellence) evaluated the consensus statements and recommendations in the fourth and final round.ResultsThe panel agreed that essential criteria to guide a skin biopsy in patients with recurrent wheals should include at least one of the following features: wheal duration >24 h, bruising/postinflammatory hyperpigmentation, and systemic symptoms. Leukocytoclasia and fibrin deposits were identified as a minimum set of UV histological criteria. As agreed by the panel members, CSU and normocomplementemic UV (NUV) may coexist in some patients.ConclusionsThe use of established criteria for the diagnosis and differential diagnosis of UV in patients with recurrent wheals can help guide the diagnostic approach and prompt earlier treatment. Further studies should investigate whether CSU and NUV are different entities or part of a disease spectrum.
Variation in biomass of cassava genotypes grown under different irrigation levels during the early growth phase
Authors: Ruangyos Chanissara , Banterng Poramate , Vorasoot Nimitr , Jogloy Sanun , Theerakulpisut Piyada , Vongcharoen Kochaphan , Hoogenboom Gerrit 
Published: October 2023

AbstractUnderstanding the performance of cassava under different irrigation levels during the early growth phase could support better decision‐making to improve yield. This study aimed to determine the performance of cassava genotypes grown under three different water regimes during the early growth phase. A strip‐plot design with four replications was used for two experimental years (2019/2020 and 2020/2021). Three irrigation levels were applied from 30 to 180 days after planting (DAP) and were assigned as factor A (W1, W2, and W3 denote 100%, 60%, and 20% crop water requirement [ETcrop], respectively), 30 cassava genotypes were assigned as factor B. Crop data were obtained at 180 and 330 DAP. The irrigation at W1 gave the highest biomass at 180 DAP as compared to W2 and W3. Well irrigation for all plots after 180 DAP did not show a difference in storage root dry weight at 330 DAP among the irrigation treatments. The genotype CMR38‐125‐77 had the highest biomass at 180 DAP for all three irrigation levels. For biomass at 330 DAP, CMR36‐31‐381 tended to produce high biomass under different irrigation levels. The genotype CMR34‐40‐43 was also identified as an ideal genotype in terms of biomass for water shortage conditions during the early growth phase of cassava. These genotypes can serve as parental sources for breeders as they have the potential to grow under different water regimes.
Cooperative Chiral Lewis Base/Palladium‐Catalyzed Asymmetric Syntheses of Methylene‐Containing δ‐Lactams
Authors: Zebrowski Paul , Monkowius Uwe , Waser Mario 
Published: October 2023

AbstractWe herein report a two‐step approach for the enantioselective synthesis of novel chiral δ‐lactams. By using a cooperative chiral ITU/achiral Pd‐catalyst system, this protocol proceeds via an asymmetric α‐allylation of activated aryl esters first, followed by an acid‐mediated lactam formation. A variety of differently substituted products could be obtained with usually high levels of enantioselectivities and in reasonable yields (16 examples, up to 98 : 2 er and 73 % yield over two steps). In addition, further utilizations of the products via transformations of the exocyclic double bond were successfully carried out as well.
Assessment of biogas and syngas production from sugarcane vinasse: A sustainable alternative for the production of renewable fuels
Authors: Tonial Gabrielly Mylena Benedetti , Paraiso Paulo Roberto , de Matos Jorge Luiz Mario 
Published: October 2023

AbstractThe increasing demand for renewable energy sources as a substitute for fossil fuels has driven researchers to develop sustainable processes for biomass energy reuse in biofuel production. Based on this premise, the present study aimed to simulate the production process of synthesis gas (syngas) from vinasse, a by‐product of the sugar and alcohol industry, highlighting the applicability of this gas in transitioning toward a more renewable and sustainable energy future. The simulation was conducted in four distinct stages using the Aspen HYSYS® software. The first stage involved obtaining hydrated ethanol from sugarcane juice, followed by anaerobic digestion of vinasse to produce biogas. The third stage involved purifying the biogas to obtain biomethane. Finally, the simulation of steam methane reforming was performed to generate syngas. The modeling and simulation results demonstrated the feasibility of the process, as it generated 20.68 Nm3 of biogas (~55% vol CH4 and 45% vol CO2) per 1 Nm3 of vinasse, corresponding to 11.66 Nm3 of biomethane (~96.5% mol CH4), which aligns with national regulatory standards and the literature presented. Regarding syngas, both evaluated configurations yielded satisfactory results. The first configuration resulted in syngas with an H2/CO molar ratio of three, making it a viable source of pure hydrogen and a raw material for biofuel production, such as dimethyl ether and methanol. The second configuration, with an H2/CO molar ratio of two, holds great potential for its application in the synthesis of liquid fuels (Fischer‐Tropsch), serving as a direct substitute for gasoline, diesel, and jet fuel.
Natural resistance to cancer: A window of hope
Authors: Masoudi Mohammad , Torabi Parisa , Judson‐Torres Robert L. , Khodarahmi Reza , Moradi Sharif 
Published: October 2023

AbstractAs healthcare systems are improving and thereby the life expectancy of human populations is increasing, cancer is representing itself as the second leading cause of death. Although cancer biologists have put enormous effort on cancer research so far, we still have a long way to go before being able to treat cancers efficiently. One interesting approach in cancer biology is to learn from natural resistance and/or predisposition to cancer. Cancer‐resistant species and tissues are thought‐provoking models whose study shed light on the inherent cancer resistance mechanisms that arose during the course of evolution. On the other hand, there are some syndromes and factors that increase the risk of cancer development, and revealing their underlying mechanisms will increase our knowledge about the process of cancer formation. Here, we review natural resistance and predisposition to cancer and the known mechanisms at play. Further insights from these natural phenomena will help design future cancer research and could ultimately lead to the development of novel cancer therapeutic strategies.
Elucidating the role of blood metabolites on pancreatic cancer risk using two‐sample Mendelian randomization analysis
Authors: Zhong Hua , Liu Shuai , Zhu Jingjing , Xu Teddy H. , Yu Herbert , Wu Lang 
Published: October 2023

AbstractPancreatic ductal adenocarcinoma (PDAC) is an uncommon but highly fatal malignancy. Identifying causal metabolite biomarkers offers an opportunity to facilitate effective risk assessment strategies for PDAC. In this study, we performed a two‐sample Mendelian randomization (MR) study to characterize the potential causal effects of metabolites in plasma on PDAC risk. Genetic instruments were determined for a total of 506 metabolites from one set of comprehensive genome‐wide association studies (GWAS) involving 913 individuals of European ancestry from the INTERVAL/EPIC‐Norfolk cohorts. Another set of genetic instruments was developed for 483 metabolites from an independent GWAS conducted with 8299 individuals of European ancestry from the Canadian Longitudinal Study on Aging (CLSA) cohort. We analyzed GWAS data of the Pancreatic Cancer Cohort Consortium (PanScan) and the Pancreatic Cancer Case‐Control Consortium (PanC4), comprising 8275 PDAC cases and 6723 controls of European ancestry. The association of metabolites with PDAC risk was assessed using the inverse‐variance weighted (IVW) method, and complemented with sensitivity analyses of MR‐Egger and MR‐PRESSO tests. Potential side effects of targeting the identified metabolites for PDAC intervention were further evaluated by a phenome‐wide MR (Phe‐MR) analysis. Forty‐four unique metabolites were identified to be significantly associated with PDAC risk, of which four top‐ranking metabolites (X: 12798, X: 11787, X: 11308 and X: 19141) showed replication evidence when using instruments developed from both two cohorts. Our results highlight novel blood metabolites related to PDAC risk, which may help prioritize metabolic features for PDAC mechanistic research and further evaluation of their potential role in PDAC risk assessment.