bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blitzlichtphotolyse an Acridin und Acridan im Temperaturbereich von +25 °C bis −180 °C
Authors: Zanker V. , Prell G. 
Published: September 2023

AbstractBlitzspektroskopische Untersuchungen an 5 · 10−5 molaren Lösungen des N‐Heterozyklus Acridin im Temperaturbereich 90–300 °K zeigten, daß die primäre Photoreaktion der Acridinbase aus dem 1(n‐πTrans. Faraday Soc., im Druck.
‐Zustand erfolgt, der mit einer Aktivierungsenergie von 0,035 eV über den angeregten (π‐π)‐Singulett besetzt wird. Sie besteht in der Anlagerung eines Wasserstoffatoms aus dem Lösungsmittel. Die Kinetik der Folgereaktionen ergibt sich aus der nichtstatistischen Verteilung der Radikale nach dem Elementarakt in der Lösung.Acridan wird durch einen zweiquantigen Stufenprozeß in einen hoch angeregten Triplettzustand übergeführt, aus dem nach drei verschiedenen Primärreaktionen drei verschiedene Radikale gebildet werden.
Blitzlichtspektroskopische Untersuchungen zum Mechanismus der Triplett‐Triplett‐Annihilation
Authors: Grellmann K. H. 
Published: September 2023

AbstractDer Mechanismus der verzögerten Fluoreszenz wurde durch die Messung der Lumineszenzspektren in Abhängigkeit von der Anregungsintensität und durch die kinetische Analyse von Blitzlichtspektrogrammen am Tris‐p‐carbomethoxyphenylamin zwischen 0 und −107 °C untersucht. Der von Parker formulierte Mechanismus der Triplett‐Triplett‐Annihilation wurde durch diese Messungen erneut bestätigt.
Zur Thermodynamik der Bildung von EDA‐Komplexen im angeregten Zustand
Authors: Knibbe Henk , Rehm Dieter , Weller Albert 
Published: September 2023

AbstractDie Wechselwirkung typischer Elektrondonoren (D) mit angeregten Akzeptoren () führt in unpolaren Lösungsmitteln zu einer Fluoreszenzumwandlung, die auf der Bildung angeregter EDA‐Komplexe (A− D+) beruht. Durch Fluoreszenzmessungen wurden die Bildungsenthalpien und ‐entropien einiger solcher Reaktionen bestimmt. Während die Entropiewerte alle bei −18 ± 1 cal/grd · mol lagen, ergaben sich für die Bildungsenthalpien Werte zwischen −2,7 und −10,2 kcal/mol. Diese Werte können auch aus spektroskopischen und elektrochemischen (Redoxpotentiale) Daten der Reaktanden berechnet werden. Der Einfluß des Lösungsmittels auf die Bildungsenthalpie wird diskutiert.
Photoinduzierte Stoßprozesse im Wasserstoff
Authors: Comes F. J. , Wenning U. 
Published: September 2023

AbstractEs wird ein Verfahren beschrieben, mit dem man die Kinetik metastabiler Wasserstoffatome untersuchen kann. Grundlage des Verfahrens ist die Photodissoziation von Wasserstoffmolekülen, die durch Prädissoziation aus dem D‐Zustand erfolgt. Dabei werden angeregte Atome mit definierter Bewegungsenergie gebildet. Diese Energie kann von annähernd thermischer Energie bis zu einigen Zehntel Elektronenvolt variiert werden, indem durch primäre Lichtabsorption das Molekül in den verschiedenen Schwingungszuständen erzeugt wird.Drei verschiedene Stoßquerschnitte und ihre Abhängigkeit von der Bewegungsenergie der metastabilen Atome wurden gemessen. Zwei von ihnen beschreiben neutrale Prozesse; der dritte ist einer Chemie‐Ionisations‐Reaktion zuzuordnen, bei der das Ion H gebildet wird. Die neutralen Prozesse wurden durch Messung der Lyα‐Fluoreszenz untersucht. Bei der stoßinduzierten Fluoreszenz wird das gestoßene H2‐Molekül zur Rotation angeregt. Die Löschung der Fluoreszenz durch Stöße führt zur vollständigen Dissoziation des Stoßkomplexes. Die Wirkungsquerschnitte beider Stoßprozesse sind annähernd geometrisch, während derjenige der Chemie‐Ionisations‐Reaktion um zwei Größenordnungen kleiner und abhängig von der Geschwindigkeit der Atome ist.
Untersuchung der Photolyse von NO2 bei hohen Drucken
Authors: Troe J. 
Published: September 2023

AbstractEs wurde die Abhängigkeit der Quantenausbeute der NO2‐Photolyse bei 3660 Å vom Trägergasdruck untersucht. Für NO2‐N2‐ und NO2‐NO‐N2‐Gemische wurde die Quantenausbeute bis zu N2‐Drucken von 200 atm gemessen. Aus den Experimenten kann direkt auf die Druckabhängigkeit der Rekombinationsreaktionen O + NO2 + N2 → NO3 + N2 und O + NO + N2 → NO2 + N2 geschlossen werden: beide Reaktionen zeigen bei N2‐Drucken oberhalb etwa 10 atm einen Wechsel der Reaktionsordnung von 3 nach 2. Als Hochdruckgrenzwerte der Geschwindigkeitskonstanten ergaben sich für beide Reaktionen etwa 1,3 · 1013 cm3/mol sec. Die Messungen werden mit Experimenten zum Hochdruckbereich der unimolekularen Dissoziation von NO2 verglichen. Es kann weiter geschlossen werden, daß die Reaktionen O + NO2 → NO + O2 und O + NO2 + M → NO3 + M über NO verschiedener Struktur ablaufen müssen. Die primäre Photolyse NO2 + hv → NO + O zeigt bei N2‐Drucken um 200 atm noch keine nennenswerte Druckabhängigkeit, was auf eine sehr kurze Lebensdauer des photodissoziierenden NO hindeutet.
A novel nonsurgical therapy for peri‐implantitis using focused pulsed electromagnetic field: A pilot randomized double‐blind controlled clinical trial
Authors: Mayer Yaniv , Khoury Juan , Horwitz Jacob , Ginesin Ofir , Canullo Luigi , Gabay Eran , Giladi Hadar Z. 
Published: September 2023

AbstractPulsed electromagnetic field (PEMF) therapy modulates the immune response and is successfully used in orthopedics to treat osteoarthritis and improve bone regeneration. This may suggest that this treatment may consequently reduce peri‐implant soft tissue inflammation and marginal bone loss. To compare clinical, radiographic, and immunological results following nonsurgical treatment for peri‐implantitis with or without PEMF therapy. Patients with peri‐implantitis were included: pocket probing depth (PPD) between 6 and 8 mm with bleeding on probing (BOP); crestal bone loss between 3 and 5 mm. A novel healing abutment that contained active (test) or inactive (control) PEMF was connected. PEMF was administered via the abutment at exposure ratio of 1/500–1/5000, intensity: 0.05–0.5 mT, frequency: 10–50 kHz for 30 days. Nonsurgical mechanical implant surface debridement was performed. Patients were examined at baseline, 1 and 3 months. Clinical assessment included: plaque index, BOP, PPD, recession, and bone crest level which was radiography measured. Samples of peri‐implant crevicular fluid were taken to analyze interleukin‐1β (IL‐1β). Twenty‐three patients (34 implants; 19 control, 15 test) were included. At the follow‐up, mean crestal bone loss was lower in the test group at 1 and 3 months (2.48 mm vs. 3.73 mm, p < 0.05 and 2.39 vs. 3.37, p < 0.01). IL‐1β levels were also lower in the test group at 2 weeks (72.86 pg/mL vs. 111.7, p < 0.05). Within all the limitation of this preliminary study, the test group improved clinical parameters after a short‐term period compared to the control group.
Effects of ultra‐strong static magnetic field on the gut microbiota of humans and mice
Authors: Zhao Wen , Han Yijuan , Shao Dongyan , Han Cuicui , Tian Yixiao , Huang Qingsheng 
Published: September 2023

AbstractTo explore the effect of ultra‐strong static magnetic field on gut microbiota, 16 T static magnetic field was used to study the changes in the structure and composition of human and mouse gut microbiota in this environment. In the mouse gut microbiota, at the genus level, the magnetic field significantly decreased the relative abundances of Escherichia‐Shigella, Lactobacillus, Enterococcus, Burkholderia‐Caballeronia‐Paraburkholderia, Parasutterella, and Ralstonia and significantly increased those of Parabacteroides, Alloprevotella, Alistipes, Odoribacter, Bacteroides, Mucispirillum, Sutterella, and Prevotellaceae_UCG‐001. Similarly, at the genus level, the relative abundances of Bacteroides, Parabacteroides, Romboutsia, and Streptococcus significantly decreased in the human gut microbiota. Contrary to the changing trend of the abundance in the mouse gut, the abundances of Bacteroides and Parabacteroides in the human gut were significantly reduced under magnetic field. The BugBase phenotypic prediction analysis showed that the relative abundances of five phenotypes, including anaerobism, mobile elements, potential pathogenicity, stress‐tolerant, and biofilm formation, changed significantly in the mouse gut microbiota, while the relative abundances of two phenotypes, including Gram‐positive and Gram‐negative phenotypes, changed significantly in the human gut microbiota. The 16 T magnetic field could differently affect the composition, structure, and phenotypes of gut microbiota in human and mice, suggesting the importance of model selection in studying the biological effects of magnetic field.
MEX3C induces cognitive impairment in mice through autophagy inhibition
Authors: Wang Kai , Zhang Hao‐Nan , Du Yong 
Published: September 2023

AbstractBackgroundThe muscle excess 3 (MEX3C) protein comprises one of two conserved KH hnRNP K homology domains of the Caenorhabditis elegans protein family, a gene involved in the metabolism of key RNAs at posttranscriptional levels during the development of C. elegans, but its function in mammals is unclear.Methods and resultsIn this study, we found that MEX3C plays a key role in learning and cognitive function. The learning and cognitive abilities of MEX3C‐knockout (KO) mice were significantly decreased relative to those of wild‐type (WT) mice in behavioral experiments, including the shuttle box, Morris water maze, and new object recognition. Nissl staining showed a decrease in the number of Nissl bodies and in the maturation of hippocampal and cortical neurons. A Western blot analysis of the neuron‐specific nuclear (NeuN) protein NEUN protein showed that the expression of that protein was decreased, which was consistent with the results of Nissl staining. Of note, the expression of sequestosome I p62 and Parkin BCL‐2‐associated X (Bax) Bax and B‐cell lymphoma‐2 (Bcl‐2) Bcl‐2 proteins also showed a downward trend, suggesting that the MEX3C gene may cause a decrease in the number and maturity of neuronal cells by increasing apoptosis through the inhibition of autophagy. In addition, Golgi staining showed that the complexity of neurons in the hippocampus and cerebral cortex was reduced, and the postsynaptic density protein 95 and growth‐associated protein (GAP‐43) also showed different degrees of reduction.ConclusionThe KO of the MEX3C gene reduces the plasticity of synapses in various regions of the hippocampus, thereby affecting the function of the hippocampus and eventually causing the decline of cognitive function. On the other hand, compared with WT mice, MEX3C‐KO mice showed increased anxiety‐like behaviors in minefield and elevated plus maze tests.
Human‐specific CHRFAM7A primes macrophages for a heightened pro‐inflammatory response at the earlier stage of inflammation
Authors: Zhou Rui , Niu Keran , Wang Chaoying , He Jianghui , Huang Wenjun , Li Tao , Lan Huan , Zhang Yanmin , Dang Xitong , Mao Liang 
Published: September 2023

Abstractα7‐Nicotinic acetylcholine receptor (α7‐nAChR) is the key effector molecule of the cholinergic anti‐inflammatory pathway. Evolution has evolved a uniquely human α7‐nAChR encoded by CHRFAM7A. It has been demonstrated that CHRFAM7A dominant negatively regulates the functions of α7‐nAChR. However, its role in inflammation remains to be fully characterized. CHRFAM7A transgenic (Tg) mice were phenotypically normal and their peritoneal macrophages exhibited decreased ligand‐binding capability and, importantly, an activated gene expression profile of pro‐inflammatory cytokines. Surprisingly, when challenged with sepsis, the Tg mice showed no survival disadvantage relative to their wild‐type (Wt) counterparts. Further analysis showed that the complete blood count and serum levels of pro‐inflammatory cytokines were comparable at resting state, but the degrees of leukocyte mobilization and the increase of pro‐inflammatory cytokines were significantly higher in Tg than Wt mice at the early stage of sepsis. In vitro, peritoneal macrophages of the Tg mice exhibited an exaggerated response to lipopolysaccharides (LPSs), especially at the earlier time points and at lower dosages of LPS. Remarkably, monocytes from CHRFAM7A‐carrier showed similar dynamic changes of the pro‐inflammatory cytokines to that observed in the Tg mice upon LPS challenge. Our results suggest that CHRFAM7A increases the mobilization of leukocytes and primes macrophages that confer an enhanced immune response at the early stage of inflammation, which may lead to prompt pathogen clearance, an evolutionary advantage in less severe inflammatory conditions.
Selective Anthracene Photooxidation over Titania‐supported Single Atom Catalysts
Authors: Mekkering Martijn J. , Rothenberg Gadi , Zhang Hong , Yan Ning 
Published: September 2023

AbstractSingle‐atom catalysts (SACs) often show exceptionally high performance per metal loading. Besides benefiting from a better atom utilisation, the metal‐support interaction is more pronounced in SACs compared to traditional nanoparticle catalysts. Thus, using SACs in photochemical conversions is of great advantage where the rapid reactions often depend on the synergistic interaction of the active site with the photoactive support. Here we show the importance of this interaction by maximizing the active site/support interface using SACs. As an example, we examine the oxidation reaction of anthracene to anthracene‐9,10‐endoperoxide (EPO) in the presence of 0.1 wt% Pt/TiO2. Our SACs give a six‐fold improvement compared to dense packed nanoparticle catalysts (TOF=113 mMol Anthracene gPt−1 min‐−1 for the SAC). We attribute this to the synergy between the active site and the support. Moreover, we show that photocatalytic conversion is possible with photons of lower energy (2.7 eV) than the bandgap of pristine TiO2 (Eg=3.0–3.2 eV) thanks to organic doping of the metal oxide.
Defect‐induced Synthesis of Highly Dispersed Hydroxyapatite‐Supported Vanadium Oxide for the Oxidative Dehydrogenation of Cyclohexane
Authors: Song Xuefeng , Zhou Feng , Ma Huixia , Liu Yifu , Wu Guang 
Published: September 2023

AbstractHydroxyapatite (HAP) contains abundant defect sites and easily releases hydroxyl groups to produce new vacancies under calcination at high temperature. The highly dispersed VOx/HAP catalyst was prepared by an impregnation method using these defects as inducement. VOx species with different structures were analysed by XRD, XPS, H2‐TPR, Raman and UV–vis spectroscopy. At low calcination temperatures (500 °C and 600 °C), the V species are mainly V2O5 crystals. At high calcination temperatures (above 700 °C), VOx on the HAP surface fills these defect sites and strongly interacts with HAP to form Ca−O−V or P−O−V bands. These scattered defects improved the dispersion of V species. These highly dispersed VOx/HAP catalysts were used for oxidative dehydrogenation (ODH) of cyclohexane to cyclohexene. The highly dispersed VOx/HAP catalyst showed a high selectivity for cyclohexene, and the selectivity reached 48.2 % when the conversion of cyclohexane was 13.1 % at 410 °C.
Soluble Ruthenium Phthalocyanines as Semiconductors for Organic Thin‐Film Transistors
Authors: García‐Calvo José , Cranston Rosemary R. , López‐Duarte Ismael , Torres Tomás , Lessard Benoît H. 
Published: September 2023

AbstractRuthenium phthalocyanine (RuPcs) are multipurpose compounds characterized by their remarkable reactivity and photoelectronic properties, which yield a broad synthetic scope and easy derivatization at the axial position. However, RuPcs have been underexplored for use in organic thin‐film transistors (OTFTs), and therefore new studies are necessary to provide basic insight and a first approach in this new application. Herein, two novel RuPc derivatives, containing axial pyridine substituents with aliphatic chains (RuPc(CO)(PyrSiC6) (1) and RuPc(PyrSiC6)2 (2), were synthesized, characterized, and tested as the organic semiconductor in OTFTs. RuPc thin‐films were characterized by X‐ray diffraction (XRD), and atomic force microscopy (AFM) to assess film morphology and microstructure. 1 displayed comparable p‐type device performance to other phthalocyanine‐based OTFTs of similar design, with an average field effect mobility of 2.08×10−3 cm2 V−1 s−1 in air and 1.36×10−3 cm2 V−1 s−1 in nitrogen, and threshold voltages from −11 V to −20 V. 2 was found to be non‐functional as the semiconductor in the device architecture used, likely as a result of significant differences in thin‐film formation. The results of this work illustrate a promising starting point for future development of RuPc electronic devices, particularly in this new family of OTFTs.
Bioengineered Lactate Oxidase Mutants for Enhanced Electrochemical Performance at Acidic pH
Authors: Garcia‐Morales Raul , Zárate‐Romero Andrés , Wang Joseph , Vazquez‐Duhalt Rafael 
Published: September 2023

AbstractElectrochemical lactate biosensors based on lactate oxidase (LOx) are used for diagnostics, sports medicine, and the food industry. However, samples from these sectors may have acidic levels at which the biocatalytic activity of LOx may be diminished. In this work, the enhancement of the bio‐electrocatalytic activity of LOx at low pH by pKa modulation of its catalytic His265 was studied by rational engineering of lactate oxidase from Aerococcus viridans (AvLOx). Several candidates based on interactions with His265 were selected by in silico structural analysis. The designed variants were heterologously produced, and the S175A mutant showed considerable improvement over its wild‐type counterpart, showing 157 % of the enzymatic activity found in the wild‐type at pH 5. Bioelectrodes were assembled based on Prussian‐blue‐modified carbon paper mediator system. The electrocatalytic performance of the amperometric biosensors of S175A variant at pH 5 exhibited a linear range of 0.2–2 mM measured at 0 V vs SCE, a sensitivity of −17.52 μA/mM ⋅ cm2, representing 240 % of the sensitivity found in the wild‐type biosensor, and a limit of detection of 38 μM, lower than observed with the wild‐type enzyme. These results show that the mutant obtained offers a significant improvement in lactate biosensing at low pH.
The onset of selective laser flash sintering in undoped and doped lanthanum chromite
Authors: Matto Lezli , Hagen Deborah , Beaman Joseph J. , Kovar Desiderio 
Published: September 2023

AbstractPrevious studies have shown that selective laser flash sintering (SLFS) can be initiated in dielectrics that exhibit ionic or electronic conduction at high temperature. These materials required high laser powers to reach the temperatures where electrical conduction is sufficient to initiate SLFS. In this study, SLFS in lanthanum chromite (LC), an intrinsic electronic conductor with high conductivity, and lanthanum strontium chromite (LSC), which is doped to further increase electronic conductivity, were investigated with a focus on understanding the initiation mechanisms. Results show that the initiation of SLFS in LC and LSC occurs when electronic charge carriers are activated and flow to the electrode where the current is measured. A combination of carriers produced at the electrode, temperature‐activated intrinsic charge carriers, and extrinsic charge carriers present in LSC due to doping are responsible for the facile initiation of SLFS.
Gold(I)‐Catalyzed Ring‐Closing Alkyne‐Carbonyl Metathesis for the Synthesis of Butenolides
Authors: Su Zhenjie , Amin Pathan Mosim , Wang Shaozhong 
Published: September 2023

AbstractAlkyne‐carbonyl metathesis is a type of carbon‐carbon forming reaction involving the construction a carbon‐carbon double bond and a carbonyl group in one transformation. Herein, a Au(I)‐catalyzed ring‐closing alkyne‐carbonyl metathesis protocol has been developed to make densely substituted γ‐butenolides from propargyl α‐ketoesters. It features 100 % atom economy, excellent substrate flexibility and benign functional group tolerance. Mechanistic studies demonstrate that the coordinative interaction between the gold catalyst and the alkyne might initiate the transfer of an oxygen atom and the formation of the carbon‐carbon double bond. By using this gold‐catalyzed ring‐closing alkyne‐carbonyl metathesis as a key step reaction, four naturally occurring butenolide‐type compounds including decumbic acid (45 % yield for 3 steps), deoxyisosporothric acid (32 % yield for 5 steps), lichesterinic acid (34 % yield for 5 steps) and isomuronic acid (6 % yield for 8 steps) have been synthesized starting from commercially available starting materials.
Using machine learning to predict adverse events in acute coronary syndrome: A retrospective study
Authors: Song Long , Li Yuan , Nie Shanshan , Feng Zeying , Liu Yaxin , Ding Fangfang , Gong Liying , Liu Liming , Yang Guoping 
Published: September 2023

AbstractBackgroundUp to 30% of patients with acute coronary syndrome (ACS) die from adverse events, mainly renal failure and myocardial infarction (MI). Accurate prediction of adverse events is therefore essential to improve patient prognosis.HypothesisMachine learning (ML) methods can accurately identify risk factors and predict adverse events.MethodsA total of 5240 patients diagnosed with ACS who underwent PCI were enrolled and followed for 1 year. Support vector machine, extreme gradient boosting, adaptive boosting, K‐nearest neighbors, random forest, decision tree, categorical boosting, and linear discriminant analysis (LDA) were developed with 10‐fold cross‐validation to predict acute kidney injury (AKI), MI during hospitalization, and all‐cause mortality within 1 year. Features with mean Shapley Additive exPlanations score >0.1 were screened by XGBoost method as input for model construction. Accuracy, F1 score, area under curve (AUC), and precision/recall curve were used to evaluate the performance of the models.ResultsOverall, 2.6% of patients died within 1 year, 4.2% had AKI, and 4.7% had MI during hospitalization. The LDA model was superior to the other seven ML models, with an AUC of 0.83, F1 score of 0.90, accuracy of 0.85, recall of 0.85, specificity of 0.68, and precision of 0.99 in predicting all‐cause mortality. For AKI and MI, the LDA model also showed good discriminating capacity with an AUC of 0.74.ConclusionThe LDA model, using easily accessible variables from in‐hospital patients, showed the potential to effectively predict the risk of adverse events and mortality within 1 year in ACS patients after PCI.
Fluorescence and Phosphorescence Energy Transfer in Cucurbituril‐Based Supramolecular Systems
Authors: Berdnikova Daria V. , Chernikova Ekaterina Y. 
Published: September 2023

AbstractSupramolecular systems demonstrating resonance energy transfer have recently became a topical area on the borderline of supramolecular chemistry, photochemistry, photophysics and biology. The modularity of supramolecular interactions is a prerequisite for fine tuning of optical properties, which is difficult to achieve by other means. As a component of such systems, cucurbit[n]uril (CB[n]) macrocycles can play a wide spectrum of roles from anchoring of FRET pairs and modulation of the optical output to providing biocompatibility of FRET stains for cell imaging. The aim of this Review is to outline the development of the CB[n]‐based systems with fluorescence (FRET) and phosphorescence (TS‐FRET) energy transfer and to highlight achievements, challenges and perspectives of this fascinating combination of a classical photophysical process and a classical supramolecular host. Particular attention in this Review is given to the current and potential applications of the reviewed systems.