bluuebunny/crossref_metadata_2025_split huggingface dataset:
Separation of lithium isotopes by countercurrent‐exchange‐electrolysis
Authors: Arkenbout G. J. , Boerboom A. J. H. , Smit W. M. 
Published: October 2023

AbstractThe separation of the lithium isotopes by countercurrent‐exchange‐electrolysis was investigated. In this process the separation is based on an exchange between a lithium amalgam and a solution of a lithium salt, transported in countercurrent through a column. It appeared possible to obtain a satisfactory countercurrent transport in a packed column. Sand with a particle size between 0.35 and 0.5 mm was found to be a suitable packing material. The reflux at the bottom of a column, where the lithium is transported from the amalgam to the electrolyte solution (anodic reflux) was realized by a continous method based on exchange‐electrolysis. The cathodic reflux is obtained by evaporating the solvent dimethyl formamide, transferring the lithium chloride into water and electrolyzing the lithium chloride solution in water. Experiments carried out during 20 to 40 hours in an exchange‐column with a length of 1 to 2 m resulted in an increase of lithium‐6 content from 7.5 to 13% at the bottom of the column and a decrease of lithium‐6 content from 7.5 to 5.3% at the top of the column.
Die Bestimmung von Gleichgewichtskonstanten aus kinetischen Messungen
Authors: Kohler Gerold , Wendt Hartmut 
Published: October 2023

AbstractGleichgewichtskonstanten wie z. B. die Komplexkonstante für die Bildung des inner‐sphere‐Komplexes von Metallkomplexen \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm K}_{\rm i} {\rm =}\frac{{{\rm [MeX]}}}{{{\rm MeH}_{\rm 2} {\rm OX}}} $\end{document} oder die Hydratationskonstante von Carbonylverbindungen \documentclass{article}\pagestyle{empty}\begin{document}$ K_{\rm H} {\rm = }\frac{{{\rm [R}_{\rm 1} {\rm R}_{\rm 2} {\rm C(OH)}_{\rm 2} {\rm]}}}{{{\rm [R}_{\rm 1} {\rm R}_{\rm 2} {\rm C = O]}}}, $\end{document}
die mit statischen Messungen nur schwierig oder prinzipiell nicht bestimmt werden können, lassen sich mit Hilfe der Drucksprungmethode nicht nur durch Relaxationszeitmessungen bestimmen. Die Auswertung der Amplituden der Relaxationsoszillogramme bietet eine weitere Möglichkeit zur Bestimmung oder Abschätzung derartiger Gleichgewichtskonstanten. Auf diese Weise wurde die Konstante Ki für folgende Komplexe bestimmt: VOSO4, BeSO4 und FeCl2+.Außerdem wurde die Hydratationskonstante des Ninhydrins (die zweite Hydratationskonstante des Triketoindans) bestimmt und das Reaktionsvolumen der Hydratation abgeschatzt. Die entwickelte Methode eignet sich besonders zur Bestimmung der Hydratationskonstanten von α‐Keto‐Carbonsäuren und anderer saurer Carbonylverbindungen, bei denen die Hydratation eine merkliche Änderung der Azidität bewirkt und deren Hydratation so schnell erfolgt, daß eine anderweitige Bestimmung der Hydratationskonstanten ausgeschlossen erscheint.
Über das Wärmeleitvermögen von organischen Reaktorkühlmitteln im flüssigen und dampfförmigen Zustand
Authors: Reiter F. W. 
Published: October 2023

AbstractEs wird berichtet über Wärmeleitfahigkeitsmessungen an flüssigem Diphenyl, o‐, m‐, p‐Terphenyl und Mischungen hiervon bis in die Nähe des normalen Siedepunktes, an gesättigten Dämpfen von Diphenyl, o‐, m‐, und p‐Terphenyl bis zu Dampfdrucken von 2–3 Atmosphären und an flüssigem und gesättigtem dampfförmigem Benzol bis in die Nähe des kritischen Punktes.Die Bestimmungen wurden nach der stationären Hitzdrahtmethode durchgeführt. Der experimentelle Fehler wird auf 2% geschätzt. Eine Darstellung in reduzierten Einheiten zeigt, daß für die Wärmeleitfähigkeit der gesättigten Dämpfe der hier untersuchten Stoffe das Theorem der übereinstimmenden Zustande sehr gut erfüllt ist, während dies für den flüssigen Zustand nicht der Fall ist.
Austauschstromdichten und Reaktionsmechanismen der Sauerstoffelektrode
Authors: Hamann Karl H. 
Published: October 2023

AbstractDie kathodische Reduktion des Sauerstoffes vollzieht sich in zwei Stufen unter Aufnahme von jeweils zwei Elektronen. Die Reduktion des Zwischenproduktes H2O2 ist so stark gehemmt, daß im allgemeinen nur die erste Stufe für den Stromfluß bestimmend ist.Die somit vorliegende Sauerstoff‐Peroxid‐Elektrode stellt eine Zweifachredoxelektrode mit den Austauschstromdichtenjo, OX undjo,red dar. Die Berechnung der Austauschstromdichten aus den Stromdichte‐Spannungs‐Kurven ergab, daß im gesamten pH‐Bereich jo, OX ≪ jo, red ist, d.h., die Aufnahme des ersten Elektrons ist für die Reduktion des Sauerstoffes zu H2O2 geschwindigkeitsbestimmend. Die Abhängigkeit der Austausch‐stromdichtejo, OX vom pH‐Wert zeigt sowohl an blankem als auch an platiniertem Platin im Neutralbereich ein ausgeprägtes Minimum und einen exponentiellen Anstieg zu zwei etwa gleich hohen Maxima im stark sauren und im stark alkalischen Gebiet.Der Versuch einer Bestimmung der Reaktionsmechanismen der Sauerstoff‐Peroxid‐Elektrode aus den gewonnenen experimentellen Daten führte im sauren Bereich zu den beiden ersten Teilschritten:
Die kathodische Reduktion von Cu‐I‐oxid‐Elektroden als Beispiel für den Mechanismus der Reduktion eines Halbleiter‐Kristalls
Authors: Schöppel H. R. , Gerischer H. 
Published: October 2023

AbstractAn Einkristallen des p‐Leiters Cu‐I‐oxid wurde die kathodische Reduktion des Kristallgitters im Kontakt mit einem Elektrolyten untersucht. Es zeigt sich, daß in Einklang mit theoretischen Überlegungen die Reduktion der Halbleiteroberfläche zu metallischem Kupfer nur unter Verbrauch von Leitungselektronen abläuft.
Doppelresonanz‐Methoden
Authors: Möbius K. 
Published: October 2023

AbstractDoppelresonanz‐Methoden in der Molekülspektroskopie, bei denen die Probe resonanzhaft mit zwei Strahlungsfeldern bestrahlt wird, überstreichen den gesamten Spektralbereich vom Radiofrequenzgebiet über das Mikrowellen‐, Infrarot‐, Sichtbare bis ins UV‐Gebiet. Die Mehrzahl dieser Methoden zeichnet sich gegenüber den entsprechenden Einfachresonanzen durch 1. Verbesserung der spektralen Auflösung und/oder durch 2. Verbesserung der Nachweisempfindlichkeit aus. Die Auflösung wird durch Einführung zusätzlicher Auswahlregeln, die Nachweisempfindlichkeit durch “Quantentransformation” gesteigert. Häufig beruht der Doppelresonanzeffekt auf einer beobachtbaren Intensitätsänderung einer Linie, während das zweite Strahlungsfeld die entsprechenden Besetzungszahlen ändert. Voraussetzung dafür ist, daß die Energieniveaus, zwischen denen Beobachtungs‐ und Pumpübergänge induziert werden, genügend gut miteinander kommunizieren, indem sie gemeinsam Energieniveaus haben oder durch Relaxationsübergange oder durch die Strahlungsfelder verkoppelt werden. Diese gemeinsamen Gesichtspunkte der Doppelresonanz‐Methoden werden an Beispielen aus der NMR (INDOR, Torrey‐Oszillationen), EPR (ELDOR, ENDOR, ODMR) und Mikrowellen‐Rotationsspektroskopie (MODOR) diskutiert.
I and Thou? Challenges to dialogical pedagogy in a diverse London secondary school
Authors: Soye Emma 
Published: October 2023

AbstractA growing body of literature suggests that ‘intercultural education’ is an important tool for transformative learning about oneself and the other. Yet little is known about the challenges and opportunities of intercultural education in practice, particularly in light of an increasing focus in Western education policy on testing and standardisation. This article uses ethnographic and focus group research in an ethnically diverse secondary school in East London to empirically explore the opportunities and challenges of intercultural education in practice. It highlights similarities between the concept of intercultural education and Martin Buber's theory of the ‘I−Thou’ encounter, suggesting that this dialogical relation has the potential to transform stereotypes and develop personhood. The research findings show how teachers at the East London secondary school employed dialogical techniques to encourage critical perspectives among their students and to cultivate their trust, a key element of I−Thou encounter. The findings also, however, draw attention to the deleterious impact of the marketised education paradigm on the dialogical relation, demonstrating how a policy focus on attainment and the narrow national curriculum limit opportunities for dialogue in the classroom and erode trust between teacher and student. The article argues that there is a clear and urgent imperative for change within the Western education system if Buber's dialogical pedagogy is to bear fruit and transformative learning is to take place.
Catechol‐Amyloid Interactions
Authors: Le Nghia T. K. , Kang Eun Joo , Park Ji Hun , Kang Kyungtae 
Published: October 2023

AbstractThis review introduces multifaceted mutual interactions between molecules containing a catechol moiety and aggregation‐prone proteins. The complex relationships between these two molecular species have previously been elucidated primarily in a unidirectional manner, as demonstrated in cases involving the development of catechol‐based inhibitors for amyloid aggregation and the elucidation of the role of functional amyloid fibers in melanin biosynthesis. This review aims to consolidate scattered clues pertaining to catechol‐based amyloid inhibitors, functional amyloid scaffold of melanin biosynthesis, and chemically designed peptide fibers for providing chemical insights into the role of the local three‐dimensional orientation of functional groups in manifesting such interactions. These orientations may play crucial, yet undiscovered, roles in various supramolecular structures.
Controllable Structural Transformation of Non‐Porous Propyl‐Malonate Hexakis[60]fullerene by Chloroform Uptake/Release
Authors: Fernández‐Bartolomé Estefanía , Santos José , Rodriguez‐Sánchez Eider , Sañudo E. Carolina , Martín Nazario , Sánchez Costa José 
Published: October 2023

AbstractThe design of dynamic structures with high recognition host‐guest materials capable to host selectively small volatile molecules is an emergent field of research with both fundamental and applied implications. The challenge of exploring novel materials with advanced functionalities has led to the development of dynamic crystalline structures promoted by soft interactions. Here, a new pure organic dynamic framework based on hexakis[60]fullerene that are held together by weak van der Waals interactions is described. This crystalline structure is capable of absorbing and releasing chloroform, through internal structural reorganization. This research provides new insight into the design of organic molecular crystals for selective adsorption applications.
Conservative treatment using laser diode and systemic chemotherapy for early‐stage bilateral retinoblastoma: A 14‐year prospective cohort study
Authors: Phan Thi Anh Thu , Derumigny Alexis , Duong Minh Cuong , Desjardins Laurence , Cung Tuyet Anh , Nguyen Cong Kiet 
Published: October 2023

AbstractBackgroundSolid evidence of the safety and effectiveness of retinoblastoma (RB) conservative treatment using thermotherapy and systemic chemotherapy with long‐term follow‐up is scarce, especially in low‐resource countries.AimsThis study examined the outcomes of this treatment and associated predictors in Vietnam to strengthen the current RB treatment protocol focusing on preserving eye and vision in low‐resource settings.Methods and resultsA prospective cohort study was conducted at Ho Chi Minh City Eye Hospital in Vietnam from 2005 to 2019. All eligible patients with bilateral RB (one eye already removed and another eye classified as group A or B) and without previous treatment were recruited. All patients received thermotherapy and six cycles of systemic three‐agent chemotherapy repeated every 4 weeks. A standardized questionnaire was used to collect information on study participants' age, symptoms, tumor characteristics, treatment, and outcomes. Among 50 eyes of all 50 patients with a median age of 9 (4–20) months, 34 eyes were in group B (68%). The median follow‐up time was 60 (60–84) months. All 139 preserved tumors regressed mostly to type 4 (70.4%) and type 3 (23.7%) scars. Kaplan–Meier analysis found the overall globe‐salvage rate at 5 years of 91.9% (95% CI: 80.1%–97.7%). Most eyes (41/50, 82%, 95% CI: 69.2%–90.2%) had a final visual acuity ≥0.1. The visual acuity is higher when tumors regressed to a type 4 scar (p = .007, AOR = 8.098, 95% CI: 1.79–36.53) which also shows less enucleation than a type 3 scar (p = .002, AOR = 0.06, 95% CI: 0.01–0.37%). Gender effect on visual acuity after treatment was significant and may be due to discrimination. No major complications were recorded.ConclusionConservative treatment of early‐stage RB is safe and effective. Long‐term, thorough follow‐ups of patients post‐treatment are needed. The regression patterns of scars could be a useful indicator of treatment failure.
Fracture Mechanism of Nanocomposite of Metal and Graphene with Defect Pores
Authors: Hu Xin , Li Lujuan , Cao Qianqian , Piao Zhongyu , Liu Hao , Gu Zhiqing 
Published: October 2023

AbstractMolecular dynamics simulations were performed to investigate the fracture mechanism and mechanical response of Ni/Graphene nanocomposites under nanoindentation. The effects of size and location of defect pores were explored by examining the pore structure transition, microstructure transition, variation of HCP atomic fraction and dislocation density with indentation depth, load‐displacement relationship, and stress distribution. It was found that when the long edges of the pore are located along the longer dimension, the pores are fractured by indentation forces from the short edges. The closer the pore is to the indent, the smaller loading force is required for the pores to reach its fracture limit. For the long edges located along the transverse direction, the maximum indentation depth increases with the distance of the pore away from the indenter. The density of HCP atoms and dislocations in the composite gradually increases with the indentation depth. To understand the physical mechanism of the fracture behavior, we also evaluated the stress distribution in graphene at the fracture point.
Wheel‐based 5G fronthaul/backhaul hybrid MDM‐NGPON/FSO system under Gamma‐Gamma turbulence and weather effects
Authors: Kumari Meet , Arya Vivek 
Published: October 2023

SummaryThis work presents the bidirectional and symmetric 40 Gbps wheel architecture comprising 16 channels‐based bidirectional hybrid next generation passive optical network with free space optics (NGPON/FSO) system using mode division multiplexing (MDM) scheme. The system incorporates a low‐cost high bandwidth and integrated time and wavelength division multiplexing with orthogonal frequency division multiplexing (TWDM‐OFDM) for data transmission over mixed fiber‐FSO links to various end users at donut modes 0 and 1. This system enhances the fifth generation (5G)‐based networks reliability, survivability, and flexibility, especially in rural places where the core fiber link may be damaged/destroyed under diverse turbulent and weather conditions. The obtained results depict the faithful multimode fiber range of 100 km with fixed FSO range of 100 m at −17 dBm receiver sensitivity and low power penalty of 0.2 dB at 10−9 bit error rate. Maximum FSO range of 2800 m under weak‐to‐strong Gamma‐Gamma turbulence and the effect of fog, rain, snow, and snow with rain can be obtained successfully with fixed 50 km fiber length. Also, the proposed wheel architecture provides superior performance over hybrid ring‐mesh architecture with high split ratio of 1:64. Moreover, the system can sustain up to 70 remote nodes at symmetric 10 Gbps throughput providing high gain, high optical signal‐to‐noise ratio, and low noise figure. The comparative literature work also reveals that the proposed architecture offers high bandwidth, security, long‐reach, and cost‐effectiveness in 5G fronthaul/backhaul networks.
Keeping cool with poop: Urohidrosis lowers leg surface temperature by up to 6°C in breeding White storks
Authors: Cabello‐Vergel Julián , Villegas Auxiliadora , Gutiérrez Jorge S. 
Published: October 2023

AbstractStorks (Ciconiidae) are renowned for defecating on their legs when exposed to high temperatures, a phenomenon known as “urohidrosis.” Previous work suggested that this behavior can cool down the blood supply to the legs and thus prevent hyperthermia in captive storks when overheated. However, no study has quantified the magnitude or duration of its evaporative cooling effect in free‐ranging birds. Here, we combine urohidrosis data with thermal imaging and microclimate data to investigate the thermoregulatory significance of urohidrosis in White storks Ciconia ciconia during the breeding season. We show that urohidrosis can reduce leg surface temperature by up to 6.7°C (4.40 ± 1.04°C). Yet its cooling effect was of short duration (lasting no more than 2.5 min) and decreased with time since defecation. Thus, for urohidrosis to significantly contribute to heat dissipation, storks must perform it repeatedly when overheated. Indeed, an individual can perform up to 11 urohidrosis events per hour; our estimates indicate that repeated urohidrosis could represent a significant amount of heat loss during short time span, equivalent to 4% of daily field metabolic rate for an adult stork. Our results point to an absence of differences in the cooling efficiency of urohidrosis between adults and nestlings, probably because all nestlings were recorded during the last phase of the ontogeny of thermoregulation. Besides, during the hottest days, adult storks delivered water to their nestlings, which might allow them to replenish body water reserves to sustain urohidrosis and other heat dissipation behaviors such as panting or gular fluttering. Our results indicate that urohidrosis might buffer the impact of high temperatures in breeding storks, preventing overheating and lethal hyperthermia. Gaining knowledge about behavioral thermoregulation in the heat is therefore crucial to better predict the future persistence and vulnerability of species under different climate warming scenarios.
Reactivity of [Sm(DippForm)2(thf)2] with Substrates Containing Azo Linkages
Authors: Peedika Paramban Ramees , Guo Zhifang , Deacon Glen B. , Junk Peter C. 
Published: October 2023

AbstractThis paper explores the interaction of divalent [Sm(DippForm)2(thf)2] with substrates containing azo linkages. Treatment of [Sm(DippForm)2(thf)2] with trans‐azobenzene results in formation of mononuclear [Smlll(DippForm)2(Ph2N2)(thf)] ⋅ 3THF (1) or dinuclear [Smlll(DippForm)(Ph2N2)(thf)]2 ⋅ 4THF (2) and [Sm(DippForm)3] depending on the reaction stoichiometry, where azobenzene has undergone either a one or two electron reduction. These reactions parallel the corresponding reactions of [Sm(C5Me5)2(thf)2], but the coordination of [N2Ph2]− in 1 differs significantly from that of {Sm(C5Me5)2(Ph2N2)(thf)}. On the other hand, the structure of 2 is similar to that of the pentamethylcyclopentadienyl analogue. The reaction of [Sm(DippForm)2(thf)2] with 1H‐1,2,3‐benzotriazole also yielded a trivalent samarium complex containing benzotriazolate (btz), [Smlll(DippForm)2(btz)(thf)] ⋅ THF (3), and suggests more utilization of 1H‐1,2,3‐benzotriazole in divalent lanthanoid reduction chemistry is possible.
Joint species distribution modeling with competition for space
Authors: Kettunen Juho , Mehtätalo Lauri , Tuittila Eeva‐Stiina , Korrensalo Aino , Vanhatalo Jarno 
Published: October 2023

AbstractJoint species distribution models (JSDM) are among the most important statistical tools in community ecology. However, existing JSDMs cannot model mutual exclusion between species. We tackle this deficiency in the context of modeling plant percentage cover data, where mutual exclusion arises from limited growing space and competition for light. We propose a hierarchical JSDM where latent Gaussian variable models describe species' niche preferences and Dirichlet‐Multinomial distribution models the observation process and competition between species. We also propose a decision theoretic model comparison and validation approach to assess the goodness of JSDMs in four different types of predictive tasks. We apply our models and methods to a case study on modeling vegetation cover in a boreal peatland. Our results show that ignoring the interspecific interactions and competition reduces models' predictive performance and leads to biased estimates for total percentage cover. Models' relative predictive performance also depends on the predictive task highlighting that model comparison and assessment should resemble the true predictive task. Our results also demonstrate that the proposed JSDM can be used to simultaneously infer interspecific correlations in niche preference as well as mutual competition for space and through that provide novel insight into ecological research.
Research progress on the calculation model of critical liquid carrying flow of gas well
Authors: Zheng Jie , Li Jiahui , Dou Yihua , Zhang Yichen , Yang Xu , Zhang Yarong 
Published: October 2023

AbstractThe accumulation of liquid in gas wells has become a prevalent problem in the middle and later stages of gas well development with different wellbore structures, which seriously affects the production efficiency of gas wells. To precisely forecast the generation time of liquid accumulation in gas wells and timely adopt drainage gas production technology, the literatures on gas critical liquid‐carrying flow calculation models for vertical wells, inclined wells and horizontal wells were analyzed and summarized. The results show that the research on the calculation models for gas critical liquid‐carrying flow rate in vertical and inclined wells is relatively mature. However, because of the unique wellbore structure of horizontal wells, the gas‐liquid two‐phase flow pattern and distribution of droplets and liquid‐film are complex, leading to a lack of understanding of gas liquid carrying mechanism throughout the whole wellbore of existing horizontal wells, and we established a calculation model of gas critical liquid‐carrying flow rate in horizontal wells considers single factors. Based on the above summary and analysis, the research direction of the calculation model for gas critical liquid‐carrying flow rate in the entire wellbore of horizontal wells is pointed out. Combining the gas liquid‐carrying test of entire wellbore of the horizontal well, considering the distribution form of droplets and liquid‐film, the aggregation and fission between droplets, and the energy exchange between gas and liquid, the gas liquid‐carrying mechanism of the entire wellbore of horizontal well is revealed, clarifying the most easy to liquid‐accumulating well sections in the whole horizontal well, and a calculation model of gas critical liquid‐carrying flow rate of horizontal well considering multiple factors is established, providing crucial theoretical foundation and technical support for the drainage and gas recovery of a horizontal well.
Multifunctional elastomeric composites based on 3D graphene porous materials
Authors: Ding Meichun , Zhao Demin , Wei Rui , Duan Zhenying , Zhao Yuxi , Li Zeyang , Lin Tianhao , Li Chenwei 
Published: October 2023

Abstract3D graphene porous materials (3GPM), which have low density, large porosity, excellent compressibility, high conductivity, hold huge promise for a wide range of applications. Nevertheless, most 3GPM have brittle and weak network structures, which limits their widespread use. Therefore, the preparation of a robust and elastic graphene porous network is critical for the functionalization of 3GPM. Herein, the recent research of 3GPM with excellent mechanical properties are summarized and the focus is on the effect factors that affect the mechanical properties of 3GPM. Moreover, the applications of elastic 3GPM in various fields, such as adsorption, energy storage, solar steam generation, sensors, flexible electronics, and electromagnetic wave shielding are comprehensively reviewed. At last, the new challenges and perspective for fabrication and functionalization of robust and elastic 3GPM are outlined. It is expected that the perspective will inspire more new ideas in preparation and functionalization of 3GPM.