bluuebunny/crossref_metadata_2025 huggingface dataset:
Einfluß der Substitution auf Fluoreszenzquantenausbeuten und Lebensdauern angeregter Singulett‐Zustände monosubstituierter Naphthaline in Lösung
Authors: Lentz P. , Blume H. , Schulte‐Frohlinde D.
Published: October 2023

Fluoreszenzquantenausbeuten und Fluoreszenzspektren von Naphthalin, von 18 monosubstituierten Naphthalinen und von Benzanthren wurden in Cyclohexan und Methanol unter Ausschluß und in Gegenwart von Sauerstoff bei 25°C bestimmt. Aus der Sauerstofflöschung ergeben sich Werte für die Lebensdauer des ersten angeregten Singulett‐Zustandes sowie für die Geschwindigkeitskonstanten der Fluoreszenz und der strahlungslosen Desaktivierung. Die Quantenausbeuten der Fluoreszenz sind von Art und Stellung polarer Substituenten, von wenigen Ausnahmen abgesehen, nur wenig abhängig. Im Gegensatz dazu ändern sich die Lebensdauern um mehr als eine Größenordnung.

Die Ergebnisse zeigen, daß polare Substitution die Geschwindigkeitskonstanten der Fluoreszenz und der strahlungslosen Desaktivierung stark und gleichsinnig beeinflußt. Dieser Effekt kommt in den entsprechenden Quantenausbeuten nicht zum Ausdruck.
Electrochemiluminescence of Energy‐Deficient Systems II. The Role of Excimer Formation in the Pure Perylene System
Authors: Grabner E. W. , Brauer E.
Published: October 2023

The reaction enthalpy Δ H of the chemiluminescent electron‐transfer reaction between perylene radical cations and anions has been estimated from electrochemical measurements. The comparison of H with the energies of the excited states of perylene leads to the conclusion that excited singlet molecules, the emission of which is observed, cannot be formed directly; rather excited triplets are produced in the electron‐transfer reaction which yield excited singulets via triplet‐triplet annihilation. This mechanism is confirmed by the analysis of the ecl intensity‐time curves. The long‐wavelength component occuring in the ecl spectrum of perylene is ascribed to excimer emission in agreement with the experimental results. These suggest the assumption that the intensity ratio of the long‐wavelength component to the fluorescent component is determined by the fact that perylene triplets—dependent on electrolysis time ‐ are quenched by excess radical ions in the reaction zone; the excimers, however, are not.
Das Verhalten von salpetriger Säure und Salpetersäure an der rotierenden Scheibenelektrode III. Berechnung der autokatalytischen Konstante aus der “ verkehrten Rührabhängigkeit” der kathodischen HNO3‐Reduktion
Authors: Schmid Gerhard , Lobeck Martin A. , Keiser Helmuth
Published: October 2023

Die “ verkehrte Rührabhängigkeit” der kathodischen HNO3‐Reduktion zu HNO2 kann in der Nähe ihrer Inversion zur “ normalen Rührabhängigkeit” fast quantitativ aus bekannten kinetischen Konstanten errechnet werden. Sie beruht auf der in der Tiefe der Diffusionsschicht homogen ablaufenden autokatalytischen Reaktion zwischen HNO3 und dem kathodisch gelieferten NO. Es wird eine graphische Auswertungsmethode abgeleitet, die es in einfacher Weise gestattet, von der “ verkehrten Rührabhängigkeit” auf die Gröβe der autokatalytischen Konstante zu schließen. Diese ergibt sich mit einer Gröβe, wie sie nach der Abel‐Schmidschen Kinetik zu erwarten ist.
The thermoelectric power of fluid mercury in the density range of the metal nonmetal transition
Authors: Schmutzler R. W. , Hensel F.
Published: October 2023

The absolute thermoelectric power of liquid and supercritical mercury has been measured between 600°C and 1700°C at pressures up to 3300 bar. For that purpose a cell of forged molybdenum and pure sintered alumina was developed which allows the simultaneous measurement of the thermoelectric power S and the electrical conductivity σ of liquid and gaseous mercury. The measurements were performed in an internally heated high pressure vessel.

A strong density dependence of S and σ is observed. If the mercury density is decreased from 12 g/cm3 to 5 g/cm3, S varies continuously from ‐ 23 μV/deg to ‐ 550μV/deg indicating a gradual transition from a metallic to a nonmetallic state. It is proposed that a pseudogap is formed in expanded mercury and that the states in the pseudogap become localized for densities smaller than 9 g/cm3. For densities smaller than this σ and S are consistent with excitation of electrons from localized states at the fermi energy to extended states at the mobility edge.
Gel‐Permeations‐Chromatographie, Möglichkeiten und Grenzen
Authors: Heitz Walter
Published: October 2023

Die verschiedenen Theorien über den gelchromatographischen Prozeß werden diskutiert. Der Haupttrenneffekt wird durch den molekülgrößenbedingt zugänglichen Anteil α des Porenvolumens VI der stationären Phase verursacht. Der Verteilungskoeffizient K. der durch die unterschiedliche Wechselwirkung des Polymeren mit dem reinen Lösungsmittel bzw. mit der Gelphase bedingt ist. hat demgegenüber einen untergeordneten, aber deutlich meßbaren Einfluß. In Ausnahmefällen kann der Verteilungseffekt dominieren und zu einer Inversion der Abhängigkeit des Molekulargewichtes vom Elutionsvolumen führen.

Eine normierende Eichkurve zwischen molekülspezifischen Größen und dem Elutionsvolumen, bei der diese Wechselwirkung vernachlässigt wird, kann nur für Polymere mit K = 1 gültig sein.

Die Ursachen der Peakverbreiterung werden erläutert und ihr Einfluß auf die Berechnung enger und breiter Molekulargewichtsverteilungen diskutiert.

Gekrümmte Säulen zeigen in Übereinstimmung mit den Aussagen von Giddings bei Oligomerentrennung keine Verminderung der Trennleistung.
Affinitäts‐Chromatographie
Authors: Kovàts E. Sz.
Published: October 2023

Es wurde versucht, anhand eines einfachen Beispieles den Term “Affinitäts‐Chromatographie” zu definieren, als eine chromatographische Trennung bei welcher die Trennung mit Hilfe spezifischer Wechselwirkungskräfte bewerkstelligt wird. Es wird gezeigt, daß die Suche nach solchen Effekten vor allem für die Flüssigkeits‐Chromatographie nötig sind.
Thermofraktographie
Authors: Stahl Egon
Published: October 2023

Die Weiterentwicklung des thermischen Mikro‐Abtrenn‐Transfer‐ und Auftrageverfahrens (TAS) führte zur Thermofraktographie (TFG). Die hierzu notwendigen apparativen Vorrichtungen (TASOMAT und Steuerteil) sind beschrieben. Wenige Milligramme einer Probe werden bei der TFG im linearen Temperaturanstieg z. B. von 20 auf 450°C erhitzt. Die flüchtigen und kondensierbaren Bestandteile. sowie die Thermolyseprodukte von Polymermaterial fängt man dabei kontinuierlich und fraktioniert als Startband auf einer DC‐Platte auf. Nach der Chromatographie erhält man auf diesem Wege auch aus komplexen Proben bislang schwer analysierbarer Gemische. wie z. B. Kaugummi, Lignine, gefärbte Mischgewebe, Fette mit Zusätzen usw., schnelle Informationen über die Zusammensetzung.
Vergleiche der ESR‐Linienbreiten des Mn2+ ‐Ions in Lösungen
Authors: Stockhausen M.
Published: October 2023

Die ESR‐Linienbreiten (B) von Mn‐Salzlösungen nehmen im allgemeinen mit abnehmendem Dissoziationsgrad zu. Um speziell Spektren des freien (solvatisierten) Ions auszusondern, werden Auswerteverfahren und Unsicherheiten der Bestimmung von B im Fall komplexer Spektren diskutiert. B freier Ionen in 12 geeigneten Lösungsmitteln (bei 9 GHz) wird verglichen; es nimmt z. B. mit der Viskosität zu. In Mischungen mit Wasser durchläuft B ein Maximum, das Mischsolvaten zugeschrieben wird. Die Frage der Unterscheidbarkeit verschiedener Relaxationsmechanismen wird diskutiert. Bei kleineren Komplexen ist B im Einklang mit der Annahme, daß rotatorische Modulation der Nullfeldaufspaltung dominiert, obwohl Modulation durch Ligandenfeldfluktuation nicht auszuschließen ist. Bei größeren Komplexen dominiert dieser Prozeß wahrscheinlich.
Berechnung der Molekül‐ und Gitterschwingungsfrequenzen und angenäherten Intensitäten sowie Interpretation des Phasenübergangs bei 116°K des kristallinen Hexamethylbenzols
Authors: Bougeard D. , Bleckmann P. , Schrader B.
Published: October 2023

Alle Molekül‐ und Gitterschwingungsfrequenzen sowie die Schwingungsformen des kristallinen Hexamethylbenzols wurden berechnet und den beobachteten Infrarot‐ und Ramanbanden zugeordnet. Die Werte für die Kraftkonstanten des allgemeinen Valenzkraftfeldes wurden zum Teil von anderen Molekülen übernommen und durch Frequenzabgleich angepaßt. Die hierzu notwendige Zuordnung von beobachteten und berechneten Frequenzen wurde durch Berechnungen der Infrarotintensität der Gerüstschwingungen und der Ramanintensität der Gitterschwingungen erleichtert. Alle Molekülschwingungsfrequenzen konnten mit einer mittleren Abweichung von 1 % abgeglichen werden. Die drastischen Änderungen im Gitterschwingungsspektrum beim Übergang in die Tieftemperaturmodifikation bei 116°K, deren Struktur noch nicht bekannt war, wurden durch Berechnungen und durch Untersuchung der Spektren des Hexadeuteromethylbenzols interpretiert. Offensichtlich befindet sich in der Tieftemperaturphase nur ein Molekül in der Bravais‐Zelle in einer Lagesymmetrie mit Symmetriezentrum und dreizähliger Achse, eine Raumgruppe Di3d, i = 1,3,5 mit z = 1 wäre ideal.
Der Druckeinfluβ auf die Bildung von Hetero‐Excimeren I. Das System 1,2‐Benzanthracen‐Diäthylanilin in unpolaren Lösungsmitteln
Authors: Pollmann P. , Weller A.
Published: October 2023

Mit Hilfe von Fluoreszenzmessungen wurde die Bildung von Hetero‐Excimeren zwischen 1,2‐Benzanthracen und N,N‐Diäthylanilin bei 25°C in einer Reihe unpolarer Lösungsmittel bei Drücken bis 5000 bar untersucht. Es wird gezeigt, daβ die mit der Hetero‐Excimerenbildung verbundene Volumkontraktion, — Δ V, aus der Druckabhängigkeit von Fluoreszenzspektrum und Lösungsmittelviskosität in sehr guter Näherung auch dann bestimmt werden kann, wenn in dem für die Auswertung verwendeten Druckbereich das Assoziationsgleichgewicht im Anregungszustand nicht mehr eingestellt ist.
Interferenzmikroskopische Untersuchung des Wachstums von Einkristallen am Beispiel des Hexamethylentetramins
Authors: Florian W. , Heyer H.
Published: October 2023

Durch interferenzmikroskopische Beobachtung wachsender Einkristallflächen kann gleichzeitig die Wachstumsgeschwindigkeit und das Verhältnis der Höhe zum Abstand der molekularen Wachstumsstufen bestimmt werden. Die Untersuchungen wurden an (110)‐Flächen von Hexamethylentetraminkristallen durchgeführt, die bei 50 °C und Übersättigungen zwischen 5 und 25% aus dem Dampf wuchsen. Bei konstanter Übersättigung treten gleichzeitig mit einem Wechsel oder einer Veränderung des wirksamen Wachstumszentrums sprunghafte Änderungen der Wachstumsgeschwindigkeit und des Verhältnisses der Stufenhöhe zum Stufenabstand auf, während die Fortschreitgeschwin‐height to the step distance changes while the velocity of the step growth remains constant.

Die Versuchsergebnisse entsprechen einem Wachstumsmechanismus unter Mitwirkung von Schraubenversetzungen über einmolekulare Stufen mit sprunghaften Änderungen des Stufenabstandes.
Palladium and Proton Knight Shift in Palladium Hydride
Authors: Brill P. , Voitländer J.
Published: October 2023

The nuclear magnetic resonance of 105Pd has been observed in α‐PdHn for the first time. The resonant field was measured at 75°C as a function of hydrogen pressure p within the entire α phase region. A linear relationship between Knight shift and hydrogen concentration has been established by comparison with the p(n) absorption isotherm at 75°C. Moreover, it has been found that the 105Pd Knight shift K and the susceptibility x of α‐PdHn are linearly related. From the K — X dependence a value of ‐(1.80 ± 014)% for the Knight shift in pure palladium metal at 75 °C and a value of ‐(1.49 ± 015)% for PdH0.025 at 75 °C could be determined. This may be attributed to the decreasing 4d spin susceptibility within the α phase.

The proton Knight shift in α‐PdHn was also studied at 75°C. Similarly to the 105Pd Knight shift the 1H Knight shift in α‐PdHn depends linearly on hydrogen concentration and susceptibility. Knight shifts between ‐(93 ± 8) ppm for PdH0.014 and ‐(50 ± 5) ppm for PdH0.035 relative to the bare proton have been obtained.
On the Kinetics of the Formation of NaDS Micelles
Authors: Herrmann U. , Kahlweit M.
Published: October 2023

The kinetics of the formation of NaDS micelles between 7.5 and 20 °C was investigated using a pressure jump apparatus. The theoretical prediction that 1/τ increases linearly with increasing NaDS concentrations could not be confirmed. Instead, the relaxation process becomes detectible at concentrations well below the cmc. There 1/τ increases rather steeply, to flatten off in a convex curve. The addition of water structure breakers like Urea, Biuret or Pyridol accelerates the relaxation process, while solubilization of Octanol slows down the process.
Zur Temperaturabhängigkeit der Quadrupol‐Kopplungskonstante von 63Cu in Cu2HgJ4
Authors: Becker K. D. , Herzog G. W.
Published: October 2023

Es wurden die kernmagnetischen Resonanzen von 63Cu in der Tieftemperaturphase von Cu2HgI4 beobachtet. Die Messungen wurden zwischen ‐ 130 °C und 70 °C bei Meßfrequenzen von 3,5 bis 14 MHz durchgeführt.

Die Spektren zeigen eine statische Quadrupolaufspaltung 2. Ordnung der Zentrallinie. Die daraus ermittelte Quadrupol‐Kopplungskonstante stimmt gut mit dem Wert überein, den die Näherungsrechnung für ein starres Punktladungsgitter liefert. Die Kopplungskonstante hängt im Bereich von ‐ 130 °C bis 50 °C linear von der Temperatur ab; diese Abhängigkeit wird auf Schwingungen der Cu+‐Ionen zurückgeführt, deren Frequenz im Rahmen eines einfachen Modells bestimmt wird.

Eine Abweichung der Kopplungskonstante vom linearen Verlauf wird im Zusammenhang mit der bei 70 °C stattfindenden Phasenumwandlung in die strukturell fehlgeordnete Hochtemperaturphase diskutiert. Oberhalb dieser Umwandlung konnten keine kernmagnetischen Absorptionen mehr beobachtet werden.
Solvent Isotope Effect of Pyruvic Acid Hydration
Authors: Menzel H. M.
Published: October 2023

The solvent isotope effect on the hydration constant, the dissociation constant and the rate constants for the uncatalysed and specific acid catalysed dehydration of pyruvic acid is investigated. The pK of the dissociation constant of the ketoacid is by 0.29 smaller in H2O than in D2O. The ratio of the hydration constant of undissociated pyruvic acid (K/K) is 0.83, while the ratio of the rate constant of dehydration is 2.65 for the uncatalysed reaction and 1.33 for lyonium ion catalysis. The results are discussed in terms of the possibility of intramolecular hydrogen bonding.
Fluorescence of Free Radicals: A Method for Determining Dissociation Energy Limits
Authors: Zare Richard N.
Published: October 2023

In an elementary gas‐phase atom‐transfer reaction, A + BC → AB + C, a lower bound to the dissociation energy of the AB molecule can be deduced from a knowledge of the dissociation energy of the BC molecule and from the knowledge of the highest internal state of the AB product that is populated by the reactive collision process. This latter information may be obtained spectroscopically either from detection of AB chemiluminescence or from detection of the AB product through laser‐induced fluorescence. These two methods are illustrated for the elementary reactions Al + O3 and Al + O2, from which lower bounds are derived for D00(AlO) of 5.13 ± 0.06 eV and 5.23 ± 0.04eV, respectively.
Spectroelectrochemical Study of Mediators I. Bipyridylium Salts and Their Electron Transfer Rates to Cytochrome c
Authors: Steckhan Eberhard , Kuwana Theodore
Published: October 2023

In many potentiometric titrations of biological electron transfer components, mediators are often employed to act as electron transfer mediators between the components and the potentiometric electrode. Certain mediators have been employed recently as electrogenerated titrants of components in coulometric titrations, particularly in some spectroelectrochemical studies. In this paper, the optical and electrochemical characteristics of some bipyridylium salts are examined as mediator‐titrants. These salts (dications) undergo a reversible one electron reduction to the radical cation which can be a good reductant. Spectroelectrochemistry has also been applied to the evaluation of the rate of electron transfer from the radical to oxidized cytochrome c. The results reported herein are a part of our interest in evaluating the electron transfer properties of heme proteins found in the mammalian respiratory system.
Derivation of the Transport Equation for Multicomponent Diffusion through Capillaries in the Transition Region between Gas‐Diffusion and Knudsen‐Diffusion
Authors: Hesse D.
Published: October 2023

The transport equation for multicomponent diffusion through a very long capillary in the transition region is derived using Boltzmann's H‐function. In discussing this function for a mixture of ideal gases enclosed in a cylinder having a finite ratio of cylinder surface and volume it is shown that‐the free enthalpy dissipation for isothermal diffusion in the absence of external forces contains two terms: the dissipation in the interior of the cylinder volume and at the surface. Using Onsager's principle of least dissipation of energy one obtains the transport equation mentioned above. It is, however, only valid for very long capillaries. In shorter tubes “end correction” will influence the transport process.
Der Existenzbereich cholesterischer Mesophasen bei hohen Drücken Die Phasenübergänge smektisch/cholesterisch und cholesterisch/isotrop‐flüssig
Authors: Pollmann P.
Published: October 2023

Die Druckabhängigkeit der Phasenübergangstemperaturen smektisch/cholesterisch und cholesterisch/isotrop‐flüssig zweier binärer Mischungen von Cholesteryloleylcarbonat und Cholesterylchlorid wird bis 2000 bar bestimmt. Dabei zeigt sich, daß der Existenzbereich der cholesterischen Phase zwischen der smektischen und isotrop‐flüssigen mit steigendem Druck erweitert wird. Aus der Druckabhängigkeit der Phasenübergangstemperaturen und den durch die Phasenübergänge verursachten Volumensprüngen werden die damit verbundenen Enthalpieänderungen berechnet.

Das angewendete neue Meßverfahren zur Bestimmung der Phasenübergänge nutzt die in einem engen Wellenlängenbereich auftretende Lichtreflektion cholesterischer Mesophasen aus.
Berechnung der Protonenschwingung in Wasserstoffbrüicken
Authors: Zigan F.
Published: October 2023

In einer Wasserstoffbrücke AH —B wirkt auf das Proton das Potential W= UA + UB. Vorausgesetzt wird UA = FA(RA) · GA(ΦA). RA, ΦA sind Polarkoordinaten in einem mit A fest verbundenen System, dessen Pol MA auf einer Symmetrieachse durch A, doch i. allg. nicht in A liegt. FA ist die ‐ an |MAA| ≠ 0 angepaßte – Potentialfunktion von Lippincott und Schroeder. GA hat die Form GA(ΦA) = 1 ‐ aA sin2bAΦA. Analog sind UB, RB, ΦB definiert. Die Symmetrieachsen von UA, UB liegen in der x,y‐Ebene. Berechnet werden für verschiedene geometrische Konfigurationen Gleichgewichtslage und Schwingungseigenschaften des Protons, letztere mit Hilfe des Tensors der zweiten Ableitung von W nach x, y, z.

Die Schwingungseigenschaften sind u. a. abhängig von |MAA|, |MBB|. In der linearen Brücke schwingt das Proton rotationssymmetrisch um AH. Der Übergang zur geknickten Brücke verursacht u. a. folgende Effekte: Die Gleichgewichtslage des Protons verschiebt sich. Die beiden Knickfrequenzen spalten auf, wobei diejenige der x, y‐Schwingung deutlich abnimmt. Die Hauptschwingungsachsen führen gegenüber AH eine Drehung aus, die in den meisten Fällen der von HB entgegengerichtet ist.
The Electronic Structure of Aromatic Amines: Photoelectron Spectroscopy of Diphenylamine, Iminobibenzyl, Acridan and Carbazole
Authors: Haink H. J. , Adams J. E. , Huber J. Robert
Published: October 2023

Photoelectron spectroscopic data of diphenylamine, iminobibenzyl, acridan and carbazole are presented and discussed in the light of the influence of molecular geometry. The PE bands have been assigned on the basis of a CNDO calculation.
Pulse Polarographic Measurements of the Oxidation of Ti(III) by NH3OH+ in Oxalic Acid
Authors: Clauss H.
Published: October 2023

The rate constant, k, of the oxidation of Ti(III) by NH3OH+ ions in oxalic acid is determined by pulse polarography and the results compared to those obtained by dc polarography. In 10−3 M solutions of K2TiO(C2O4)2, k* = 80 ± 5 sec−1 M−1 (k* = kf, where f is the stoichiometric factor of the oxidation reaction) whereas dc polarography gives a value of k* = k = 42 ± 2 sec−1 M−1. Decreasing the concentration of the titanyl salt changes k* from k* = 80 ± 5 to k* = 40 ± 5 sec−1 M−1 (at 10−5 M salt concentration). The increase of the polarization time at constant drop time also decreases the value of k* to 45 ± 5 sec−1 M−1. During the oxidation NH2 radicals are formed. The different results from the pulse and the dc measurements and the dependence of the value of k* on the polarization time are explained by subsequent reactions of the NH2 radicals.
To the Mechanism of the Formation of Micelles in Sodiumdodecylsulfate(SDS)‐solutions
Authors: Folger R. , Hoffmann H. , Ulbricht W.
Published: October 2023

Kinetic measurements using relaxation techniques were carried out with solutions of pure Sodiumdodecylsulfate (SDS) and of SDS which had different surfactants added (Dodecylalcohol (DOH), Sodiumtetradecylsulfate (STS), Dodecylpyridiniumchloride (DPCI)). The results have shown, that some of the earlier investigations on SDS were effected, probably by the presence of small amounts of Dodecanole (DOH), or homologs of SDS, for example Sodiumtetradecylsulfate (STS). Two relaxation times could be measured in the pure solutions. The faster relaxation time was dependent on the concentration of the solution, while the slower one was almost independent on the total concentrationco. For both processes it was possible, to measure a relaxation‐time at the critical micelle concentration (cmc), from which rate constants for the dissociation of a monomer out of the micelle and the disappearance of a micelle were determined. The rate constants for the processes An+1→ An+ Aand An→ nA are at 20°C 1.9 · 104s−1and 900s−1respectively. With the addition of small amounts of Dodecylpyridiniumchloride (DPCl) a third relaxation time could be observed, which was associated with the formation of mixed micelles. The rate constant for the decomposition of a mixed micelle with a single molecule of DPCl in the micelle was determined to 13.8s−1(at 20°C).
Infrarot‐ und Ramanspektrum des Ammoniaks bei hohen Drücken und Temperaturen
Authors: Buback M.
Published: October 2023

Die Infrarotabsorption und Ramanstreuung von Ammoniak wurde vor allem im überkritischen Bereich bis 300°C (Tk = 132,5°C) und bis 1250 bar gemessen. Bei überkritischer Temperatur werden flüssigkeitsähnliche Dichten erreicht.

Die kontinuierliche Temperatur‐ und Dichtevariation der Bandengestalt, der Lage der Maximumsfrequenz sowie der Absorptions‐ bzw. Streuintensität wurde zwischen 3000 und 3600 cm−1 untersucht. In diesem Bereich liegen die symmetrische (v1) und asymmetrische (v3) Valenzschwingung sowie der in eine symmetrische (2v04) und asymmetrische Komponente (2v24) aufgespaltene Oberton der Deformationsschwingung v4.

Durch Messung von Infrarot‐ und Ramanspektrum bei kontinuierlicher Dichtevariation gelingt eine sichere Zuordnung der Banden. Das Infrarotspektrum bei hoher Temperatur und hoher Dichte läßt sich fast ausschließlich auf die Absorption der asymmetrischen v3‐ und 2v24‐Schwingungen zurückführen. Daraus wird geschlossen, daß das pyramidale NH3‐Molekül mit zunehmender Dichte abflacht. Die gemessenen Ramanspektren, in denen v1 und 2v24‐Streuung dominieren, bestätigen dieses Ergebnis und zeigen an, daß die Pyramidenhöhe des NH3‐Moleküls im Dichtebereich um 0.44g/cm3 minimal wird und bei noch höheren Dichten wieder ansteigt.
Lithium‐charakteristische Banden in den Infrarot‐Spektren von Lithium‐1,3‐Diketonaten
Authors: Funck E. , Jungermann A.
Published: October 2023

An den IR‐Absorptionsspektren von sechs Lithium‐Diketonaten (LiR1COCHCOR2; R1, R2 = CH3, C2H5, C6H5, OCH3, OC2H5) wurde durch 6Li–7Li‐Isotopensubstitution untersucht, inwieweit und in welchem Bereich Banden auftreten, die für die Lithium‐Sauerstoff‐Konfiguration charakteristisch sind. Bei einigen Verbindungen mit tetraedrischer LiO4‐Koordination sind solche Schwingungen, die in etwa als antisymmetrische Dehnungsschwingung der LiO4‐Gruppe beschrieben werden können, im Bereich um 450 cm−1 nachgewiesen. Li‐empfindliche Banden mit typischen Isotopenverschiebungen von 4–6% wurden in einem sehr weiten Bereich von 240–600 cm−1 gefunden. Einige wenige Banden zeigen mit 7–8% Verschiebungen, die größer sind, als man sie für eine Reihe von denkbaren LiOn‐Konfigurationen maximal erwarten könnte. Obwohl es sich um Verbindungen handelt, bei denen man ähnliche Verhältnisse in bezug auf die Li–O‐Bindung vermuten könnte, sind die Spektren sowohl in der Lage der Banden wie auch in der Verteilung der Isotopeneffekte sehr verschieden. Alles spricht dafür, daß eine Zuordnung mit einem einfachen Modell nicht möglich ist.

Von einer Verbindung, dem Li‐Acetylacetonat, ist die Kristallstruktur bekannt. An Einkristallen mit polarisierter Strahlung gemessene Spektren ermöglichten weitergehende Zuordnungen.
Dielectric Properties of Liquid Surface Zones, II. The Monohalogenobenzenes in Thin Layers Between Platinum‐Iridium Plates
Authors: Peschel G. , Schnorrer R.
Published: October 2023

The dielectric constant of thin layers of fluid monohalogenobenzenes (fluoro‐, chloro‐, and bromobenzene) between two condenser plates made of a platinum‐iridium alloy, was measured at 105 cps. A remarkable decrease of the dielectric constant was found chiefly in small temperature ranges about 30–40° above the melting point which proved to be ranges of structural transition. At these temperatures monohalo‐genobenzene layers exhibit also a disjoining pressure and an altered viscosity, respectively. For fluoro‐ and chlorobenzene the dielectric anomalies in boundary layers seem to prevail down to lower temperatures. This phenomenon is explained by a cooperative long‐range structuring of the liquid near the metal surface.
A phantom for targeted endomyocardial biopsy training
Authors: Contento Jacqueline , Cleveland Vincent , Ehtiati Tina , Olivieri Laura , Kanter Joshua
Published: October 2023

Endomyocardial biopsy (EMB) of the right ventricular (RV) septal surface during cardiac catheterization is the standard method to assess cardiac allograft rejection, heart failure, or inflammatory cardiomyopathies. We developed methodology using a three‐dimensional (3D) printed phantom to provide proof of concept for using biplane overlay technology for targeted EMB. A standard bioptome and steerable sheath were used to discern feasibility of biopsy for seven regions of the RV septum guided by 3D overlay. This novel biopsy phantom can help train operators in biopsy techniques, and biplane overlay technology has the potential to advance targeted EMB in transplant and cardiomyopathy populations.
Modified leopard‐crawl technique using intravascular lithotripsy balloon in calcified coronary lesions
Authors: Kuramitsu Shoichi , Kaneko Umihiko , Matsuna Nobuki , Kashima Yoshifumi , Fujita Tsutomu
Published: October 2023

Intravascular lithotripsy (IVL) has emerged as a novel therapy for the treatment of coronary calcification. Numerous studies have reported the safety and efficacy of IVL in calcified coronary lesions, while IVL balloon‐uncrossable calcified coronary lesions are sometimes encountered in clinical practice. This case report represents a novel technique called “modified leopard‐crawl” to advance the IVL balloon antegradely by creating significant calcium cracking forward when the enhanced stent visualization system reveals that the distal emitter seems adjacent to calcification. This technique might be a valuable alternative when conventional procedures fail and has the potential to enhance the clinical applicability of IVL in daily practice.
Diversification of Simple Arenes into Complex (Amino)cyclitols
Authors: Angelini Elisa , Martinelli Matteo , Roà Eugenio , Ungarean Chad N. , Salome Christophe , Lefebvre Quentin , Bournez Colin , Fessard Thomas C. , Sarlah David
Published: October 2023

Highly oxygenated cyclohexanes, including (amino)cyclitols, are featured in natural products possessing a notable range of biological activities. As such, these building blocks are valuable tools for medicinal chemistry. While de novo synthetic strategies have provided access to select compounds, challenges including stereochemical density and complexity have hindered the development of a general approach to (amino)cyclitol structures. This work reports the use of arenophile chemistry to access dearomatized intermediates which are amenable to diverse downstream transformations. Practical guidelines were developed for the synthesis of natural and non‐natural (amino)cyclitols from simple arenes through a series of strategic functionalization events.
Investigation of Low‐Temperature Synthesis Strategy for a Cubic Phase Li7La3Zr2O12
Authors: Alam Tausif , Das Avirup
Published: October 2023

In the present work, a solid‐state reaction (SSR) method is used to prepare a cubic phase Li7La3Zr2O12 (C‐LLZO) via a two‐step process from tetragonal phase Li7La3Zr2O12 (T‐LLZO). To identify the tetragonal to cubic phase change region a thermogravimetric analysis (TGA) of the precursor material is carried out. Subsequently, another TGA analysis is carried out for tetragonal sample to identify tetragonal to cubic phase transition regions. TGA of tetragonal sample shows multiple phase transition regions at ≈250°, 400°, and 610 °C. A series of T‐LLZO samples are reheated to obtain C‐LLZO. The T‐LLZO samples reheated at 150 °C, and 650 °C show cubic symmetry, whereas the sample heated at 450 °C and 950 °C show mixed phase. The obtained C‐LLZO samples have lattice constant a = b = c = 12.9389 Å for 150 °C heated sample and a = b = c = 12.9375 Å for 650 °C heated samples with space group Ia‐3d. Considering the TGA of the T‐LLZO sample and XRD analysis of the T‐LLZO samples reheated at different temperatures, the transition at ≈150 °C is attributed to the hydration process of T‐LLZO and 650 °C is due to structural deformation of LLZO.
Advances in wildlife abundance estimation using pedigree reconstruction
Authors: Rosenblatt Elias , Creel Scott , Gieder Katherina , Murdoch James , Donovan Therese
Published: October 2023

The conservation and management of wildlife populations, particularly for threatened and endangered species are greatly aided with abundance, growth rate, and density measures. Traditional methods of estimating abundance and related metrics represent trade‐offs in effort and precision of estimates. Pedigree reconstruction is an emerging, attractive alternate approach because its use of one‐time, noninvasive sampling of individuals to infer the existence of unsampled individuals. However, advances in pedigree reconstruction could improve its utility, including forming a measure of precision for the method, establishing required spatial sampling effort for accurate estimates, ascertaining the spatial extent of abundance estimates derived from pedigree reconstruction, and assessing how population density affects the estimator's performance. Using established relationships for a stochastic, spatially explicit simulated moose (Alces americanus) population, pedigree reconstruction provided accurate estimates of the adult moose population size and trend. Novel bootstrapped confidence intervals performed as expected with intensive sampling but underperformed with moderate sampling efforts that could produce abundance estimates with low bias. Adult population estimates more closely reflected the total number of adults in the extant population, rather than number of adults inhabiting the area where sampling occurred. Increasing sampling effort, measured as the proportion of individuals sampled and as the proportion of a hypothetical study area, yielded similar asymptotic patterns over time. Simulations indicated a positive relationship between animal density and sampling effort required for unbiased estimates. These results indicate that pedigree reconstruction can produce accurate abundance estimates and may be particularly valuable for surveying smaller areas and low‐density populations.
A simple method for the assessment of electrophoretic mobility in porous media
Authors: Franck Nicolás , Vera Candioti Luciana , Gerlero Gabriel S. , Urteaga Raúl , Kler Pablo A.
Published: October 2023

Developing paper‐based electrophoretic methods involve dealing with significant uncertainty levels when compared to their capillary counterparts. Critical information for developing these kinds of methods are the electrophoretic mobility of background electrolytes and samples. This work presents the design and characterization of a device for measuring the electrophoretic mobilities of dyes in porous media. The device was developed with the aim of validating a previously presented model and also proposing a protocol for the straightforward determination of electrophoretic mobilities in porous media when open‐channel values are already known. Whatman #1 paper was used as a model substrate as far as it is the most common porous medium substrate for paper‐based electrophoresis. The device was designed using a numerical simulation–assisted approach, utilizing OpenFOAM® and specific solvers for capillary transport and electromigration, namely porousMicroTransport and electroMicroTransport, respectively. The electrophoretic mobilities of five dyes were analyzed experimentally with the proposed device. To establish appropriate comparative values at different pHs, experiments in fused silica capillaries were also performed. An effective parameter model for describing the electrophoretic behavior of dyes in porous media, that is, the constriction factor, was found consistent with previous reports for the Whatman #1 paper. This consistency was found after considering (via direct measurements) the chromatographic effect of the medium over each dye. Consequently, the recorded values hold significant worth due to their potential for direct application in designing new experiments or devices in Whatman #1 paper. With the validation of the model through the experiments with the proposed device, those researchers interested on developing electrophoretic methods in porous substrates can make use of the open‐channel electrophoretic mobilities reported in the literature, or in the well‐known software databases, and correct them for the media of interest just by performing two simple characterization steps.
Measurement of tensile strength of well cement sheath in underground gas storage based on tensile failure method
Authors: Song Wei , Ji Yueying , Zhu Kuanliang , Yang Yan , Zhou Yan
Published: October 2023

During gas injection in gas storage, the inner pressure increase, potentially leading to tensile failure of the cement sheath. At present, the fracture strength of cement stone is measured using the Brazilian splitting method (BSM), which is prone to errors due to stress concentration at the loading point. To overcome this drawback, a novel test device and measurement method were developed to assess the tensile. This device utilizes the tensile failure method (TFM) to evaluate the sealing integrity of the cement sheath. The tensile strength tested by the BSM was found to be 40% higher than that tested by the TFM. Furthermore, based on the optimization of the cement slurry for underground gas storage (UGS) in the Jidong oilfield using both the TFM and the BSM. We found that using the BSM cannot optimize the cement slurry that meets the requirements for gas storage well cementing. The latex cement slurry was selected by the TMF for UGS well.
Cutaneous metastasis of urothelial carcinoma
Authors: Baczynski Alexandra , Medhus Emily , Skopis Penelope , Ahmed Aadil
Published: October 2023

Introduction

Cutaneous metastasis of urothelial carcinoma is a rare occurrence, accounting for a small percentage of skin metastases in cancer patients. This case presentation highlights the importance of considering cutaneous metastasis in patients with a history of urologic malignancy presenting with new dermal nodules.

Case presentation

A 79‐year‐old male with a history of papillary urothelial carcinoma of the bladder and metastasis to the rectum presented with a painful and pruritic rash in the right inguinal region. Physical examination revealed firm papulonodules forming confluent, hyperpigmented to violaceous plaques. A punch biopsy confirmed the diagnosis of cutaneous metastasis of urothelial carcinoma based on histopathological and immunohistochemical findings.

Conclusion

While cutaneous metastasis is uncommon in urothelial carcinoma, early recognition and diagnosis are crucial in guiding patient management and setting realistic expectations regarding prognosis. Timely identification of cutaneous lesions can help facilitate appropriate treatment decisions and discussions of goals of care.
Thermally treated biomass of pine (Pinus kesiya) leaves for effective removal of organic dyes from aqueous solutions
Authors: Huynh Phuong Thao , Nguyen Duy‐Khoi , Duong Bich‐Ngoc , Nguyen Phi‐Ho , Hong Phuong Nguyen Thi , Dinh Van‐Phuc
Published: October 2023

BACKGROUND

Methyl orange (MO) and methylene blue (MB) from aqueous solutions were effectively removed using thermally treated pine (Pinus kesiya) leaves. The influences of solution pH (2–10), contact time (10–240 min) and initial dye concentration (100–500 mg L−1) were found to be significant in the process of dye removal. The experimental data were fitted with four isotherm models (Langmuir, Freundlich, Sips and Temkin) and four kinetic models (Elovich, pseudo‐first‐order, pseudo‐second‐order and intraparticle diffusion). Some mechanisms of the MO and MB adsorption onto the adsorbent material were proposed and discussed.

Results

Among the four isotherm models examined, the experimental data gave the best fit with the Langmuir model. The maximum Langmuir adsorption capacities were 136.99 mg g−1 for MO and 140.85 mg g−1 for MB. Kinetic studies illustrated that the biosorption of both dyes onto pine leaves aligns with Elovich, pseudo‐first‐order, pseudo‐second‐order and intraparticle diffusion models. Thermodynamic studies showed that the uptake of the two dyes was regulated by physisorption, and it was spontaneous and endothermic in nature. Electrostatic interactions, as well as other noncovalent forces such as π–π interactions and hydrogen bonds, were mechanisms of dye adsorption on heat‐treated pine leaf biomass.

Conclusion

The present study suggests that pine leaves could be a potential biosorbent for wastewater treatment due to their high availability and production, resulting in several environmental advantages. © 2023 Society of Chemical Industry (SCI).
The Golgi complex of dopaminergic enteric neurons is fragmented in a hemiparkinsonian rat model
Authors: Cara‐Esteban Mireia , Marín María Pilar , Martínez‐Alonso Emma , Martínez‐Bellver Sergio , Teruel‐Martí Vicent , Martínez‐Menárguez José A. , Tomás Mónica
Published: October 2023

Since gastrointestinal disorders are early consequences of Parkinson's disease (PD), this disease is clearly not restricted to the central nervous system (CNS), but also significantly affects the enteric nervous system (ENS). Large aggregates of the protein α‐synuclein forming Lewy bodies, the prototypical cytopathological marker of this disease, have been observed in enteric nervous plexuses. However, their value in early prognosis is controversial. The Golgi complex (GC) of nigral neurons appears fragmented in Parkinson's disease, a characteristic common in most neurodegenerative diseases. In addition, the distribution and levels of regulatory proteins such as Rabs and SNAREs are altered, suggesting that PD is a membrane traffic‐related pathology. Whether the GC of enteric dopaminergic neurons is affected by the disease has not yet been analyzed. In the present study, dopaminergic neurons in colon nervous plexuses behave as nigral neurons in a hemiparkinsonian rat model based on the injection of the toxin 6‐OHDA. Their GCs are fragmented, and some regulatory proteins' distribution and expression levels are altered. The putative mechanisms of the transmission of the neurotoxin to the ENS are discussed. Our results support the possibility that GC structure and the level of some proteins, especially syntaxin 5, could be helpful as early indicators of the disease.

Research Highlights

The Golgi complexes of enteric dopaminergic neurons appear fragmented in a Parkinson's disease rat model.

Our results support the hypothesis that the Golgi complex structure and levels of Rab1 and syntaxin 5 could be helpful as early indicators of the disease.
Heat waves in Florida and their future from high‐resolution regional climate model integrations
Authors: Beasley Parker , Misra Vasubandhu , Jayasankar C. B. , Bhardwaj Amit
Published: October 2023

This study examines the simulation of the heatwave events over Florida from the integration of two regional climate models (RCMs) at comparatively high resolution (at 10 km grid spacing) for two decades of the current climate (1986–2005) followed by their projection in the mid‐21st century (2041–2060). The two RCMs are coupled ocean–atmosphere (CRSM) and atmosphere only (URSM), which are forced at the lateral boundaries by the corresponding simulation of the Community Climate System Model v4 (CCSM4) for both the atmosphere and the ocean. The analysis reveals a reasonable simulation of the frequency, intensity and characteristic kinematic and thermodynamic features of the heatwave events over Florida from both the RCMs with the differences between URSM and CRSM being insignificant. The future projections (2041–2060) are presented only for URSM since the projected differences from CRSM were insignificant. We found the projected change of higher frequency ranging between 20 to over 50% increase relative to the late 20th‐century frequency of heatwave events. Similarly, the projections suggest a broadening of the season of their occurrence by over 2 months. These projected changes are associated with a projected increase in the mean surface temperature, a slight increase of surface humidity but with a mean reduction of surface relative humidity, and a westward dislocation of the North Atlantic Subtropical High.
Association between a novel nutrition‐inflammation prognostic grading system and overall survival in hospitalized adults with cancer: A retrospective cohort study
Authors: Huang Jia‐Xin , Zhang Xi , Tang Meng , Zhang Qi , Deng Li , Song Chun‐Hua , Li Wei , Yang Min , Shi Han‐Ping , Cong Ming‐Hua
Published: October 2023

Background

Malnutrition and increased systemic inflammatory responses are highly prevalent in patients with cancer and they have a negative effect on prognosis. We aimed to develop a nutrition‐inflammation prognostic grading system (NIPGS) for patients with cancer, which incorporates the Nutritional Risk Screening 2002 (NRS 2002) and C‐reactive protein (CRP) levels.

Methods

This multicenter retrospective cohort study totally included 6891 patients diagnosed with cancer. A 4 × 4 matrix incorporating the four NRS 2002 categories within each of the four CRP categories was constructed. Groups with approximate hazard ratios (HRs) were clustered into one grade. The NIPGS consists of four grades, with the survival rate gradually decreasing from Grades 1 to 4. The primary outcome was overall survival (OS) and comprehensive survival analyses were performed.

Results

During a median follow‐up of 18.70 months, 2818 death cases occurred. Kaplan–Meier curve showed the survival rate decreased from Grades 1 to 4 of NIPGS (P < 0.001). The NIPGS was an independent risk factor associated with OS adjusting for confounders, with HRs increasing from 1.22 (95% confidence interval [CI], 1.09–1.36; P < 0.001) in Grade 2, 1.58 (95% CI, 1.39–1.80; P < 0.001) in Grade 3 to 1.92 (95% CI, 1.73–2.13; P < 0.001) in Grade 4. A high NIPGS grade was also associated with an increased risk of short‐term mortality, poor quality of life, and longer hospital stay and expenses. Two internal validation cohorts confirmed the results of our study.

Conclusion

The NIPGS could be an effective prognostic tool for patients with cancer.
Is the Presence of Levator Ani Muscle Avulsion Relevant for the Diagnosis of Uterine Prolapse?
Authors: García‐Mejido José Antonio , Martín‐Martinez Alicia , García‐Jimenez Rocío , González‐Diaz Enrique , Núñez‐Matas María José , Fernández‐Palacín Fernando , Carballo‐Rastrilla Sonia , Fernández‐Fernández Camino , Sainz‐Bueno José Antonio
Published: October 2023

Objective

To determine if the addition of the assessment of levator ani muscle (LAM) avulsion to the measurement of the difference in the pubis‐uterine fundus distance between rest and with the Valsalva maneuver could increase the diagnostic capacity of ultrasound for uterine prolapse (UP).

Methods

This multicenter, observational and prospective study included 145 patients. Ultrasound assessment was performed, establishing the diagnosis of UP as a difference between the pubic‐uterine fundus distance at rest and during the Valsalva maneuver ≥15 mm (standard technique), while LAM avulsion was defined as an abnormal LAM insertion in three central slices using multislice ultrasound. A binary multivariate logistic regression model was made using nonautomated methods to predict surgical UP (general population, premenopausal, and postmenopausal patients), including the difference between the pubis‐uterine fundus distance at rest and with the Valsalva maneuver as well as LAM avulsion.

Results

A total of 143 patients completed the study. The addition of LAM avulsion criteria to the standard dynamic distance‐based protocol for the diagnosis of UP resulted in a higher sensitivity for the general population (79.7 vs 68.1%) as well as for premenopausal (89.3 vs 79.9%) and postmenopausal patients (76 vs 66.1%). In contrast, the standard technique showed a higher specificity than the model based on the standard technique associated with LAM avulsion for the general population (89.2 vs 74.3%) and premenopausal women (91.7 vs 63.2%). For postmenopausal patients, the model based on the standard technique associated with LAM avulsion had a higher sensitivity (76 vs 66.1%) and specificity (91.7 vs 86.8%) than the ultrasound diagnosis of UP.

Conclusion

The implementation of the assessment of LAM avulsion in the ultrasound diagnosis of UP is useful in postmenopausal patients, increasing sensitivity and specificity relative to the ultrasound assessment based only on the difference between the pubis‐uterine fundus distance at rest and with the Valsalva maneuver.