bluuebunny/crossref_metadata_2025 huggingface dataset:
Zum Protonentransport in schwefelsauren Lösungen
Authors: Miyoshi Y. , Lorenz W. J.
Published: November 2023

Die Diffusionskoeffizienten der wandernden Ionen für den Protonentransport in schwefelsauren Alkalisulfatlösungen wurden durch zwei voneinander unabhängige Meßmethoden bei der kathodischen Wasserstoffabscheidung an der rotierenden Gold‐Scheibenelektrode bestimmt. Beide Methoden, stationäre Stromdichtepotentialmessungen unter potentiostatischen Bedingungen und nichtstationäre Transitionszeitmessungen unter galvanostatischen Bedingungen, ergaben einen mittleren Wert von Di = 2, 10 · 10−5 cm2 · s−1. Es wird gezeigt, daß sich dieser Diffusionskoeffizient aus zwei Anteilen zusammensetzt: überwiegend Diffusion von HSO4− ‐Ionen sowie von H+ ‐Ionen. Darüber hinaus werden kinetische Daten für die durchtrittsgehemmte kathodische Wasserstoffabscheidung am Gold mitgeteilt.
Torrey‐Oszillationen in heteronuklearer Doppelresonanz. II. Untersuchung 13C‐disubstituierter Moleküle natürlicher Häufigkeit
Authors: Ziessow D. , Lippert E.
Published: November 2023

Die in der Arbeit I [1] für die heteronukleare Doppelresonanz beschriebene Methode der Torrey‐Oszillationen wird zur Bestimmung von 13C‐Resonanzfrequenzen verwendet. Es wird das experimentelle Verfahren detailliert erläutert und seine Empfindlichkeit anhand der Untersuchung 13C‐disubstituierter Moleküle natürlicher Häufigkeit demonstriert. Die gemessenen Spinsysteme sind AnMX, AXY und A2XY; weitere werden diskutiert (A = H; M,X,Y = 13C). Das Vorzeichen der CC‐Kopplung für C = C und C = C ist positiv.
PVT‐Daten und Mischungsvolumina in binären Methan‐Kohlenwasserstoff‐Systemen zwischen —150 und 0°C und bis 1000 bar
Authors: Oeder D. , Schneider G. M.
Published: November 2023

In einer früher beschriebenen Hochdruckmeßzelle aus Kupfer‐Beryllium wurden die PVT‐Daten von Methan, n‐Hexan und Methylcyclopentan sowie binärer Mischungen von Methan mit n‐Hexan und Methylcyclopentan im Temperaturbereich von – 150 bis 0°C und bis zu Drucken von 1000 bar experimentell ermittelt. Die Ergebnisse bestätigen die aus dem Phasenverhalten und den kritischen p(T)‐Kurven der Systeme Methan‐n‐Hexan und Methan‐Methylcyclopentan abgeleiteten Vorzeichenvoraussagen für die Mischungsvolumina ΔV. ΔV‐Werte im System Methan‐n‐Hexan bei 200 bar, die nach einem Theorem der übereinstimmenden Zustände sowie mit einer empirischen Gleichung berechnet wurden, ergeben zwar qualitativ gute Übereinstimmung mit den Meßdaten, zeigen aber in quantitativer Hinsicht besonders in methanreichen Mischungen beträchtliche Abweichungen von den experimentellen Ergebnissen.
Molekülrechnungen zur ‐Elektronenstruktur von 9,9′‐Dianthryl
Authors: Schneider F. , Lippert E.
Published: November 2023

9,9′‐Dianthryl zeigt in Lösungen bei Änderung der Polarität und Viskosität des Lösungsmittels ein anomales Verhalten seiner Fluoreszenz [1]. Ein zur Klärung dieses Effekts entwickeltes Modell wird quantitativ untersucht, und die Ergebnisse der Molekülrechnungen werden mit den experimentellen Daten verglichen.
The Chemisorption of Carbon Monoxide and Nitrogen on Thin Nickel Films
Authors: Bradshaw A. M. , Vierle O.
Published: November 2023

The chemisorption of carbon monoxide and nitrogen on thin nickel films at low temperatures has been studied using the infrared transmission technique combined with the measurement of conductivity changes. The growth of absorption bands during carbon monoxide adsorption is complete before full coverage is reached. The appearance of the spectra and the growth of bands are compared with earlier results. The possible nature of the adsorption sites is briefly discussed.
The Effect of Various Inner Coordination Sphere Ligands on the Dissociation Rate of Nickel Malonate Complexes
Authors: Hoffmann Heinz , Yeager Ernest
Published: November 2023

The effects of a number of strongly bonding ligands on the dissociation rates of malonate bidentate nickel complexes have been examined in aqueous nickel malonate solutions using the pressure‐step and shock wave relaxation technique with conductivity readout. The opening of the malonate chelate appears to be the rate controlling step in the dissociation of the malonate. The dissociation rate constant has been compared with the observed shift in the optical absorption peaks for the d – d orbital transitions in the various mixed nickel complexes. On the basis of the comparison the various ligands other than malonate and water in the inner coordination sphere of nickel have been divided into three classes:

1. ligands that labilize the malonate chelate with the logarithm of the rate constant increasing as a linear function of the spectral shift to shorter wavelengths (e.g., pyridine, 2‐aminoethyl pyridine, ethylenediamine, 3,3′‐iminopropylamine).

2. ligands which produce only a small effect on the dissociation rate of the malonate complex although producing a substantial spectral shift to shorter wavelengths (e.g., α,α′‐bipyridine, phenanthroline, pyridine 2‐aldoxime).

3. ligands which labilize the malonate complex but do not produce any appreciable spectral shift (e.g., acetylacetone).

These effects are discussed in terms of charge on the ligand, crystal field stabilization energies and σ and π orbital character of the bonding.
Schwefelkohlenstoff‐Oxidation III. Die isotherme Oxidation von Schwefelkohlenstoff
Authors: Homann K. H. , Krome G. , Gg. Wagner H.
Published: November 2023

Die Oxidation von CS2 mit O2 läßt sich durch die in Teil I dieser Arbeit untersuchten Elementarreaktionen und die in Teil II mitgeteilten Ergebnisse zur Oxidation von OCS quantitativ beschreiben. Experimentell bestimmte Konzentrationsprofile der Ausgangsstoffe sowie der Zwischen‐ und Endprodukte werden angegeben und mit den über die Elementarreaktionen berechneten Profilen verglichen.
Some Structural Aspects of the Rotational and Translational Diffusion in Liquids
Authors: Hertz H. G.
Published: November 2023

An interconnection between the rotational correlation time of a molecule and the structure of the liquid is demonstrated. For this purpose the angular velocity correlation function is constructed by taking account of fluctuating effective moments of inertia of aggregates due to molecular association. From this correlation function the rotational diffusion coefficient or rotational correlation time is obtained. The probabilities for the occurence of various aggregates which appear in this treatment are expressed in terms of integrals, containing the orientation dependent pair distribution function and a function describing the chance that the aggregate is sufficiently long‐lived. The reorientation time increases with increasing degree of structure. A numerical example for water is presented. The situation in mixtures and the occurence of intramolecular motions is discussed. The analogous treatment for the translational self‐diffusion coefficient is sketched.
Über die intramolekulare Excimerfluoreszenz von 1,3‐bisarylpropan‐Derivaten
Authors: Klöpffer Walter
Published: November 2023

Das Fluoreszenzspektrum von Biscarbazolylpropan (BCP) weist eine konzentrationsunabhängige Excimerbande auf. Die Quantenausbeute der Monomerfluoreszenz ist nur etwa halb so groß wie bei Carbazolderivaten, die keine intramolekularen Excimere bilden können. Monomer‐ und Excimerfluoreszenz von BCP werden durch Sauerstoff unterschiedlich gelöscht.

Die quantitative Auswertung der Löschexperimente zeigt, daß eine Dissoziation von Excimeren in angeregte Monomere auftritt. Die Geschwindigkeitskonstante der Excimerbildung ist bei BCP wegen der Größe der Substituenten kleiner (108 s−1) als bei Diphenylpropan (109s−1).
Zur Messung von Elektroneneinfangquerschnitten mit Hilfe der Elektronenzyklotronresonanz
Authors: Mothes K. G. , Mihelcic D. , Schindler R. N.
Published: November 2023

Es wird ein Meßverfahren beschrieben, das es gestattet, absolute Wirkungsquerschnitte für den Einfang thermischer Elektronen in der Gasphase zu ermitteln. Das Verfahren beruht auf der Messung des Elektronenzyklotronresonanz (ECR)‐Signals photochemisch erzeugter Elektronen in einem Strömungssystem. Das ECR‐Signal und die Thermalisierung der Elektronen werden diskutiert.
Differentialkalorimeter zur Bestimmung von Verbrennungsenthalpien an Substanzmengen im Mikrogrammbereich
Authors: Müller W. , Schuller D.
Published: November 2023

Zur Bestimmung von Verbrennungsenthalpien im Mikrosubstanzbereich von einigen Vielfachen von 10 μg wurde ein auf dem Wärmeflußprinzip beruhendes Differentialmikrokalorimeter entwickelt. Die auftretenden Verbrennungsenergien können direkt mit der Verbrennungsenergie von Standardsubstanzen oder mit elektrischen Energien verglichen werden. Die erzielten Meßgenauigkeiten entsprechen denen üblicher Makromethoden. Darüber hinaus ist für sehr kleine Verbrennungswärmen (ca. 200 mJ pro Experiment) eine Absolutbestimmung bei vorheriger elektrischer Einmessung des Kalorimeters mit einer Genauigkeit bisheriger Mikromethoden möglich. Die Funktionstüchtigkeit des Kalorimeters wurde durch die Bestimmung der Standardbildungsenthalpie von Wolframtrioxid getestet.
Wechselwirkung von Überschall‐Molekularstrahlen mit Einkristall‐Oberflächen
Authors: Forth B. , Schügerl K.
Published: November 2023

Zur Untersuchung der absoluten Reaktionswahrscheinlichkeit von O2 an Si(111)‐Einkristalloberflächen wurde der Gewichtsverlust gemessen, der während der Reaktion der O2‐Molekularstrahlteilchen mit der Oberfläche durch Verdampfen des gebildeten SiO auftritt. Aus der Temperaturabhängigkeit der Reaktionswahrscheinlichkeit ließ sich eine Aktivierungsenergie von 70 bis 75 kcal/mol ermitteln, die dem Desorptionsprozeß des gebildeten SiO zuzuordnen ist. Bei hohen Temperaturen nimmt die Aktivierungsenergie ab, da die Reaktionswahrscheinlichkeit nur von der Anzahl der chemisorbierten O2‐Molekeln abhängt.
Über den Einfluß adsorbierter Gase auf die Oberflächenrekombination von Stickstoffatomen an Edelstahl
Authors: Comsa Gerda H. , Groth W.
Published: November 2023

Im Zusammenhang mit den Arbeiten an der “Großen Bonner Kugel“ sollte der Einfluß von Fremdschichten auf die Wandrekombination von Stickstoffatomen an einer Edelstahloberfläche untersucht werden. Hierzu erwies es sich als notwendig, die Methode zur Bestimmung des Rekombinationskoeffizienten aus dem Abklingen des Stickstoffnachleuchtens für den Fall sehr kurzer Abklingzeiten und sehr geringer Intensitäten weiter zu entwickeln. Auf diese Weise konnte erstmalig der Rekombinationskoeffizient für die Stickstoffatomrekombination an einer mittels Ausheizen und Ionengetterpumpen gesäuberten Edelstahloberfläche bestimmt und dessen Beeinflussung durch verschiedenartige Vorbehandlung der Oberfläche systematisch untersucht werden.
Singulett‐ und Triplettmessungen an den Phäophytinen in Abhängigkeit vom Lösungsmittel und dessen Wassergehalt
Authors: Prell G. , Zanker V.
Published: November 2023

Es werden die quantitativen Triplettabsorptionsspektren der Phäophytine in Abhängigkeit von der Acidität in Äthanol, sowie in den Lösungsmitteln (LM) Pyridin, Chloroform, Tetraehlorkohlenstoff und Benzol gemessen. Es wird keine Abhängigkeit in den Eigenschaften des Triplettzustandes hinsichtlich spektraler Bandelage und Bandenhöhe der Triplettabsorptionsspektren, sowie der Quantenausbeute der Triplettbildung (ΦPha = 0,9; ΦPhb = 0,75) und der Triplettlebensdauer (ΦPha = 0,6 ms; ΦPhb = 1,0 ms) festgestellt. Ebenso bleibt die Fluoreszenzausbeute in allen LM unverändert gegenüber Äthanol.

In Benzol wird das quantitative Singulettabsorptionsspektrum des wasserfreien Phäophytin a angegeben. Wasserfreies Phäophytin a fluoresziert nicht. Weiter wird gezeigt, daβ die Quantenausbeute der Triplettbildung in wasserhaltigem und wasserfreiem Benzol unverändert ist. Das quantitative Triplettspektrum und die Triplettlebensdauer (τPha = 0,45 ms) von wasserfreiem Phäophytin a werden angegeben.
Thermischer Zerfall gasförmiger Alkalihalogenide II: Druckabhängigkeiten und Ionenausbeuten
Authors: Luther K. , Troe J. , Gg. Wagner H.
Published: November 2023

Die thermischen Zerfallsreaktionen von NaJ, KJ, CsJ, NaCl, KCl, CsBr und LiF in der Gasphase wurden in Stoßwellen im Trägergas Argon in weiten Temperatur‐ und Druckbereichen untersucht. Dabei wurden Konzentrationsprofile zerfallender Moleküle und gebildeter Ionen aufgenommen. Ionenausbeuten und Temperatur‐ und Druckabhängigkeiten von Zerfallsgeschwindigkeiten wurden gemessen. In einigen Fällen konnte zusätzlich auf die Geschwindigkeit der Elektronenablösung an Halogenionen geschlossen werden. Zur Interpretation des Zerfalls der Alkalihalogenide wird ein Modell mit Konkurrenz zwischen Stoßanregungsprozessen und Übergang zwischen hetero‐ und homöopolaren Elektronenzuständen entwickelt.
Zum Mechanismus der Oxydation von Propen und 1‐Buten an Kupferoxidul‐Katalysatoren
Authors: Herzog W.
Published: November 2023

Als Fobgereaktion des N2O‐Zerfalls, bei dem an Kupferoxidul atomarer Sauerstoff entsteht, wird die Oxydation von Propen und 1‐Buten untersucht. Bei der Propen‐Oxydation mit N2O unterbleibt im Gegensatz zur Oxydation von Propen mit Sauerstoff die Acrolein‐Bildung. für die demnach Sauerstoffmoleküle benötigt werden. Bei der 1‐Buten‐Oxydation mit N2O wird Butadien gebildet, wobei die Selektivität bei geringerer Geschwindigkeit der Gesamtreaktion etwa gleich groβ wie mit Sauerstoff ausfällt; die Butadien‐Bildung geht demnach mit atomarem Sauerstoff vonstatten. Für die Bildung von Methylvinylketon, dem Hauptprodukt der 1‐Buten‐Oxydation, wird demgegenüber wieder molekularer Sauerstoff benötigt, da mit N2O kein Methylvinylketon entsteht.
A Modification of the Avakian‐Merrifield Method for the Determination of the Diffusion Constants of Triplet States
Authors: Nickel B.
Published: November 2023

The diffusion constants of triplet states can be determined from the time‐dependence of the delayed fluorescence if the excitation of the sample is spatially periodic (Avakian, Merrifield, Ern). As a modification of this method, excitation by two interfering coherent light beams is proposed. The time‐dependence of the delayed fluorescence is derived for this case. Possible applications are discussed.
Über den Einfluß elektrischer Felder auf das Absorptionsspektrum von Farbstoffmolekülen in Lipidschichten. II. Messungen an Rhodamin B
Authors: Schmidt S. , Reich R.
Published: November 2023

Mit Hilfe der „lock‐in”︁‐Technik werden Elektrochromiespektren von Rhodamin‐B‐Molekülen in Cadmiumarachidatschichten in dünnen Kondensatoren gemessen. Die Spektren lassen sich auf Grund theoretischer Überlegungen der vorhergehenden Arbeit deuten.

Eine Vorzugsorientierung der Rhodamin‐B‐Moleküle in den Schichten wird nicht gefunden. Ein permanentes inneres Feld von ∼1,5 · 105 V/cm erzeugt aus dem quadratischen Elektrochromie‐Effekt einen linearen Elektrochromie‐Effekt. Beide Effekte sind proportional der zweiten Ableitung der Absorptionsbande (Bandenverbreiterung). Die Dipolmomentdifferenz zwischen Grundzustand und angeregtem Zustand beträgt ∼1,7 D; die Polarisierbarkeitsdifferenz ist klein.
Phase transitions of hydrogen in metals due to elastic interaction
Authors: Alefeld G.
Published: November 2023

Hydrogen in metals can be considered as an example for a lattice gas with phase transitions.

In the first part a phenomenological discussion of the phase diagrams of hydrogen in Pd, Nb, Ta and V will be given. It will be shown that these phase diagrams show topologically great similarity to those which hold for the phase transitions gas‐liquid‐solid of a one component system.

In the second part the elastic dipole dipole interaction will be discussed. This interaction is considered to be the predominant part of the attractive interaction responsible for the “gas‐liquid” transition. Three experimental methods to measure the mean interaction energy of the lattice gas will be discussed. Experimental results for the mean interaction energy will be compared with theoretical predictions. Arguments are presented that the critical temperature for the gas liquid transition should be strongly decreased by embedding the sample into material with elastic coefficients stiffer than those of the sample.
A mechanistic theory of hydrogen embrittlement of steels
Authors: Oriani R. A.
Published: November 2023

Consideration of the relation between the cohesive energy and the surface free energy leads to the inference that dissolved hydrogen reduces the maximum cohesive resistive force of which the iron lattice is capable. This forms the basis of a mechanistic model for the velocity of hydrogen‐induced crack propagation in steels. The crack grows when the local tensile elastic stress normal to the plane of the crack equals the local maximum cohesive force per unit area as reduced by the large concentration of hydrogen drawn there by the effect of elastic stress on the chemical potential of hydrogen. The velocity of the growth is given by the solution of the relevant transport equation for the accumulation of hydrogen. Although quantifiable in principle the theory remains implicit because of current ignorance of the needed functional relationships, but some qualitative predictions and insights are possible, as well as the specification of important experiments.
Some technological problems in fusion reactor design
Authors: Forsen Harold K.
Published: November 2023

A review of possible fusion reaction cycles with the associated neutron production rates and energies is presented. Some of the problems in having to thermalize and capture these neutrons for D‐T cycles are outlined in terms of likely neutron wall currents and resulting neutron fluxes. Due to the energy of these neutrons other problems arise because of elastic and inelastic collisions. Such collision rates and displacements per atom for a “standard blanket” are presented. Problems in thermal and transient magnetic stress loading are also outlined.
Die Spektren von TiX3‐ROH‐Komplexen (X = Halogen; R = H, Methyl, Äthyl, iso‐Propyl) und ihre Deutung im McClureschen Modell
Authors: Pittel B. , Schwarz W. H. E.
Published: November 2023

Bei den Komplexen trans‐[TiX2(ROH)4]+ mit X = Cl, Br, und R = H, iso‐Propyl liegt der A1g‐ unter dem B1g‐Term, bei den Komplexen [Ti(ROH)6]3+ mit R = H, Methyl, äthyl sowie bei [TiCl6]3− und [TiCl5H2O]2− ist es umgekehrt. Die Spektren bestätigen. daβ Ti3+ mit Methanol und Äthanol einen Hexaalkohol‐, mit Isopropanol aber einen Tetraalkohol‐dichloro‐Komplex bildet.
Ligandenreaktivität und Katalyse
Authors: Kelm H.
Published: November 2023

Ein Vergleich der theoretischen Anforderungen an einen Katalysator mit den Eigenschaften von Komplexverbindungen führt zu dem Schluß, daß diese Verbindungen sich als Reaktionszentren bei katalysierten Prozessen eignen. Die gezielte Beeinflussung der physikalischen und chemischen Eigenschaften der als Liganden vorübergehend aufgenommenen Reaktantenmoleküle oder Zwischenprodukte durch das Zentralatom und die übrigen Liganden der Komplexverbindung ermöglichen im Prinzip eine Modellierung des Katalysators. Anhand ausgewählter Beispiele werden die Anwendungsmöglichkeiten und derzeitigen Grenzen der homogenen Katalyse durch Koordinationsverbindungen erläutert und diskutiert.
Teilweise diffusionskontrollierte irreversible Redoxreaktionen zwischen verschiedenen Eisenkomplexen
Authors: Holzwarth J. , Strohmaier L. , Gerischer H.
Published: November 2023

Die Kinetik der Reduktion einer Reihe von substituierten 1,10‐Phenanthrolinkomplexen des dreiwertigen Eisens durch Kaliumhexa‐cyanoferrat(II) wird mit der Strömungsmethode mit integrierender Beobachtung untersucht.

Es zeigt sich, daβ die Geschwindigkeitskonstanten dieser Redoxreaktionen teilweise durch die Diffusion der Komplexe zueinander bestimmt werden. Durch Ermittlung der Grenzgeschwindigkeit für vollständig diffusionskontrollierte Reaktionen dieses Typs zu 3,2 × 109 l/mol können die Geschwindigkeitskonstanten der reinen Elektronenübertragung erhalten werden. Diese Ergebnisse werden im Rahmen der Marcus‐Theorie diskutiert, die gefundene Übereinstimmung ermöglicht die Berechnung der homonuklearen Austauschgeschwindigkeit des Elektrons zwischen den Phenanthrolinkomplexen des zwei‐ und dreiwertigen Eisens zu 5 ± 2 × 109 l/mol sec.
Der Methanolaustausch an Metall‐Ionen
Authors: Fischer P. , Hoffmann H. , Platz G.
Published: November 2023

Die Kinetik der Bildung und Dissoziation von Metall(II)chloridkomplexen (Mn, Fe, Co) und Magnesiumtrifluoroacetat in Methanol wurde mit Hilfe einer Stoßwellen‐ und einer Drucksprungapparatur untersucht. Es wird gezeigt, daβ die Abspaltung eines Methanolmoleküls aus der inneren Koordinationssphäre des Metallions den geschwindigkeitsbestimmenden Schritt der Komplexbildung bildet und daβ ein linearer Zusammenhang zwischen der Aktivierungsenthalpie und der Aktivierungsentropie sowohl für den Solvataustausch als auch für die Anionabspaltung besteht.
Phosphoreszenzlebensdauern und ‐quantenausbeuten von Mangan(II)‐Komplexen mit Liganden der 6. und 7. Gruppe
Authors: Oelkrug D. , Wölp A.
Published: November 2023

Bei 300° und 77° wurden Phosphoreszenzabklingzeiten τ und ‐quantenausbeuten η von Mangan(II)‐Komplexen mit den Koordinationen MnHal4, MnHal6, MnChalk4, Mn(OR2)4Hal2 und Mn(OR2)2Cl4 im kristallinen Zustand bestimmt. In voneinander isolierten Komplexen ohne Dipolliganden ist η groß und kaum temperaturabhängig, nimmt mit steigender Kernladungszahl der Liganden stark ab und wird außerdem durch die Komplexsymmetrie bestimmt. In Komplexen mit Dipolliganden wird η unabhängig von der Temperatur klein. Das Ausmaß der Löschung hängt von der Schwingungsenergie der Liganden und von der Komplexkonfiguration ab. Sind die Komplexe über gemeinsame Liganden miteinander verknüpft, dann wird Phosphoreszenz bei Raumtemperatur auch ohne Anwesenheit von Dipol‐Liganden meist stark gelöscht. Bei 77° ist \eta dagegen groß. Die mittlere natürliche Lebensdauer ist etwa eine Größenordnung kleiner als im isolierten Komplex und wird nicht mehr in erster Linie durch die Kernladungszahl der Liganden, sondern durch die Mn‐Mn‐Wechselwirkung bestimmt.
Spezifische Wärmen und thermische Fehlordnung von Kupferchalkogeniden Teil II: Die Systeme Cu2S ‐ CuS und Cu2Se ‐ CuSe
Authors: Kubaschewski P.
Published: November 2023

Bei den strukturell fehlgeordneten α‐Phasen des Kupfer(I)‐Sulfids und ‐Selenids steigen in weitem Temperaturbereich die auf die Formel Cu2‐δX (X = S, Se) bezogenen spezifischen Wärmen mit wachsendem Kupferdefizit δ an. Die partiellen spezifischen Wärmen des Kupfers sind also negativ. Beim Kupferselenid ergab sich unmittelbar oberhalb der Phasenumwandlung β → α eine partielle spezifische Wärme des Kupfers, die nahe dem Dulong‐Petitschen Wert liegt. Sie nimmt jedoch mit steigender Temperatur ab und strebt in der Nähe von 450°C einem negativen Extremwert zu. Mögliche Deutungen dieses Befundes werden diskutiert.

Ferner konnten aufgrund der Messungen die Zustandsdiagramme Cu2X ‐CuX ergänzt werden.
Thermodynamic Investigations of the Helix‐Association of Biocolloids, especially of 5′‐GMP
Authors: Becker Ch. , Ackermann Th.
Published: November 2023

Guanosine‐5′‐monophosphate has the remarkable property of forming helical aggregates in aqueous solutions. This helix aggregation can be described in a model system by means of statistical thermodynamics. Furthermore the aggregation can be followed by measuring the change of the enthalpy of an aqueous solution of 5′‐GMP as a function of temperature using an adiabatic calorimeter.

In this article we give a new derivation of the theory of Peticolas. The formalism is now expanded to an application for temperature induced transitions and the temperature dependence of the degree of transition is taken into account.

The transition enthalpy of 5′‐GMP has been determined by means of an adiabatic calorimeter for various solutions having different concentrations. Furthermore the model‐parameters σ2 and δ were determined and the behaviour of the system is discussed for some special cases.
Elastic Scattering of Ions
Authors: Weise Hans‐Peter
Published: November 2023

The value of elastic scattering experiments for the determination of interaction potentials between ions and neutral particles is discussed. After a description of typical experimental setups a short introduction to the theory of rainbow scattering is given. Several methods for the evaluation of experimental results are presented. The measured differential cross‐sections and the resulting potential curves are discussed for the proton‐rare gas systems which have been extensively studied. In some cases the experimental data can be compared with quantum chemical calculations. The system He+ ‐ He is chosen to outline the symmetry effects observed in the differential elastic scattering cross‐section in the case of the symmetric rare gas ion‐rare gas atom systems. The potential depths obtained from the experimental rainbow structures are compared with the results of quantum chemical calculations and of semiempirical estimates. Some data derived from elastic scattering of He+ by rare‐gas atoms are presented. Finally experimental results are reviewed for the elastic scattering of protons by simple molecules and of H+2 by Ar‐ and Kr‐atoms.
Punktfehlstellen in Oxidmischphasen II. Beweglichkeit der Defektelektronen in (CoxMg1‐x) O und (CoxMg1‐x)2 SiO4
Authors: Schwier G. , Schmalzried H.
Published: November 2023

Beweglichkeiten von Defektelektronen in den Mischkristallen (CoxMg1‐x)O und (CoxMg1‐x)2 SiO4 als Funktion von Temperatur und Zusammensetzung x wurden aus elektrischen Leitfähigkeitsmessungen unter Benutzung der im Teil I dieser Arbeit gemessenen Defektelektronenkonzentrationen ermittelt. Mit zunehmendem Magnesiumgehalt nimmt die Defektelektronenbeweglichkeit über Größenordnungen ab. Eindeutig kann festgestellt werden, daß in den Mischkristallen ein aktivierter Sprungprozeß der Defektelektronenbeweglichkeit vorliegt. Die Aktivierungsenergie wird stark von den Nachbarschaftskonfigurationen der Kationen beeinflußt und nimmt mit zunehmendem Magnesiumgehalt zu.
Biosynthesis of Al2O3 and europium‐doped Al2O3 nanoparticle using Cymbopogon citratus (lemongrass) extract and its antibacterial property
Authors: Tanwar Shruti Nandkishor , Parauha Yatish Ratn , There Yogesh , Dhoble Sanjay Janraoji
Published: November 2023

Cymbopogon citratus‐mediated pure aluminium oxide (Al2O3) and europium (Eu)‐doped Al2O3 with different amounts of metal ion were prepared using a green synthesis method. Synthesised nanoparticles were characterised by ultraviolet (UV)‐visible spectroscopy, photoluminescence (PL), Fourier‐transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Synthesis of nanoparticles is confirmed by using UV‐visible spectroscopy showing maximum absorption at 411 and 345 nm for Al2O3 and Eu‐doped Al2O3, respectively. The antibacterial activity of prepared nanoparticles was evaluated against Pseudomonas aeruginosa, Streptococcus aureus, Escherichia coli and Klebsiella pneumoniae using a well‐diffusion technique. The effect of pure Al2O3 and Eu‐doped nanoparticles shows excellent results against P. aeruginosa, S. aureus, E. coli and K. pneumoniae.
Know the ins and outs of notifying parents about student suspensions, disciplinary actions
Authors: Rainsberger Richard
Published: November 2023

Although some student–parent relationships aren’t all we would like them to be, we do have an obligation to ensure we comply with the Family Educational Rights and Privacy Act during any disclosure of education records to parents.
Understand implications of “Dear Colleague” letter regarding webpage accessibility
Authors: Masinter Michael R.
Published: November 2023

A joint “Dear Colleague” letter issued in May by the U.S. Department of Justice and the Education Department outlines the Section 504 and Americans With Disabilities Act accessibility obligations that govern educational institutions’ public‐facing webpages. Although the “Dear Colleague” letter reiterates that all public‐facing web pages should be accessible to low‐vision, hearing‐impaired, and limited motor control users, it offers little new guidance on compliance timelines, suggesting instead that the Departments will afford some flexibility to institutions that haven’t yet come into compliance. Thus, while institutions should already have ensured as a matter of self‐interest that critical public‐facing web pages — including those related to applications, marketing, and news announcements — are accessible, institutions need not scour all public‐facing web pages to immediately root out inaccessible archival material.
Near‐fatal bleeding due to ruptured peripheral varicose vein that developed after previous orthopedic surgery: A case report
Authors: Takamatsu Jumpei , Nakajima Hajime , Nakata Masatoshi , Fukuhara Aya , Kang Jinkoo , Yasue Yuichi
Published: November 2023

Key Clinical Message

This case highlights the necessity to inform patients with vein ligation about the possibility of varicose vein formation in the periphery and brings awareness to emergency staff that bleeding could be caused by a ruptured peripheral varicose vein.
Reversible Reactions of Nitric Oxide with a Binuclear Iron(III) Nitrophorin Mimic
Authors: Sharma Vinay K. , Saini Azad , Fridman Natalia , Gray Harry B. , Gross Zeev
Published: November 2023

Construction of functional synthetic systems that can reversibly bind and transport the most biologically important gaseous molecules, oxygen and nitric oxide (NO), remains a contemporary challenge. Myoglobin and nitrophorin perform these respective tasks employing a protein‐embedded heme center where one axial iron site is occupied by a histidine residue and the other is available for small molecule ligation, structural features that are extremely difficult to mimic in protein‐free environments. Indeed, the hitherto reported designs rely on sophisticated multistep syntheses for limiting access to one of the two axial coordination sites in small molecules. We have shown previously that binuclear Ga(III) and Al(III) corroles have available axial sites, and now report a redox‐active binuclear Fe(III) corrole, (1‐Fe)2, in which each (corrolato)Fe(III) center is 5‐coordinate, with one axial site occupied by an imidazole from the other corrole. The binuclear structure is further stabilized by attractive forces between the corrole π systems. Reaction of NO with (1‐Fe)2 affords mononuclear iron nitrosyls, and of functional relevance, the reaction is reversible: nitric oxide is released upon purging the nitrosyls with inert gases, thereby restoring (1‐Fe)2 in solutions or films.
Synthesis of Anti‐Pancreatic Cancer Natural Product Majusculamide D and Analogues Reveals a Preliminary Structure‐Activity Relationships
Authors: Zhao Xiuhe , Lv Mengxue , Xi Xiaonan , Lu Yaxin , Wang Liang , Chen Yue
Published: November 2023

Comprehensive Summary

The total synthesis of majusculamide D (1) was achieved from commercially available materials. In addition, we synthesized eight analogues including three stereoisomers of majusculamide D that differ in the fatty acid chain. Six analogues including a simplified analogue 29 exhibited significant nanomolar‐level IC50 values against Panc‐1 cells in MTT assays. A preliminary SAR analysis indicated that the hydroxyl group at C10 and C2−C3 unsaturated double bond of majusculamide D were essential in maintaining the high activity against Panc‐1 cells and the orientation of C40‐Me and C42‐Me groups was tolerable.
State‐of‐the‐Art Two‐Dimensional Metal Phosphides for High Performance Lithium‐ion Batteries: Progress and Prospects
Authors: Jia Zhuoming , Kong Xianglong , Liu Zhiliang , Zhao Xiaohan , Zhao Xudong , He Fei , Zhao Ying , Zhang Milin , Yang Piaoping
Published: November 2023

Lithium‐ion batteries (LIBs) with high energy density, long cycle life and safety have earned recognition as outstanding energy storage devices, and have been used in extensive applications, such as portable electronics and new energy vehicles. However, traditional graphite anodes deliver low specific capacity and inferior rate performance, which is difficult to satisfy ever‐increasing demands in LIBs. Very recently, two‐dimensional metal phosphides (2D MPs) emerge as the cutting‐edge materials in LIBs due to their overwhelming advantages including high theoretical capacity, excellent conductivity and short lithium diffusion pathway. This review summarizes the up‐to‐date advances of 2D MPs from typical structures, main synthesis methods and LIBs applications. The corresponding lithium storage mechanism, and relationship between 2D structure and lithium storage performance is deeply discussed to provide new enlightening insights in application of 2D materials for LIBs. Several potential challenges and inspiring outlooks are highlighted to provide guidance for future research and applications of 2D MPs.
A novel algorithm for robust estimation of ants' speed on convoluted trajectories derived from their gait pattern
Authors: Choi Jibeom , Song Woncheol , Kim Woojoo , Lee Sang‐im , Jablonski Piotr Grzegorz
Published: November 2023

Accurate measurements of travel distance and the corresponding speed are crucial for the analysis of animal movements. Particularly, the trajectories of ants were used in numerous behavioral studies. However, measurements of travel distance involve the dilemma of setting the proper time window: Estimates from a short time window are vulnerable to spatial errors in observation, while estimates from a long time window lead to an underestimation of the travel distance. To overcome these difficulties, we propose a novel algorithm that successively interpolates two consecutive points of an ant's trajectory for a given time window by embracing the alternating tripod gait and other gait patterns of ants. We demonstrate that this algorithm is more reliable compared with the conventional method of travel distance estimation based on the sum of the consecutive straight‐line displacement (SLD). After obtaining speed estimates for a range of sampling time windows, we applied a fitting method that can estimate the actual speed without prior knowledge of spatial error distribution. We compared results from several methods of speed estimation extracted from the empirical and simulated data of ant trajectories. The accuracy of our algorithm was comparable with or much higher than the accuracy of the sum over the consecutive SLD with optimal window length. Hence, subjective selection of the sampling time window can be avoided by using the proposed algorithm. We provide software that enables empirical scientists to utilize the proposed methods rather than the conventional SLD method of distance and speed estimation.
Forest structural diversity is linked to soil microbial diversity
Authors: Lang Ashley K. , LaRue Elizabeth A. , Kivlin Stephanie N. , Edwards Joseph D. , Phillips Richard P. , Gallion Joey , Kong Nicole , Parker John D. , McCormick Melissa K. , Domke Grant , Fei Songlin
Published: November 2023

Efforts to catalog global biodiversity have often focused on aboveground taxonomic diversity, with limited consideration of belowground communities. However, diversity aboveground may influence the diversity of belowground communities and vice versa. In addition to taxonomic diversity, the structural diversity of plant communities may be related to the diversity of soil bacterial and fungal communities, which drive important ecosystem processes but are difficult to characterize across broad spatial scales. In forests, canopy structural diversity may influence soil microorganisms through its effects on ecosystem productivity and root architecture, and via associations between canopy structure, stand age, and species richness. Given that structural diversity is one of the few types of diversity that can be readily measured remotely (e.g., using light detection and ranging—LiDAR), establishing links between structural and microbial diversity could facilitate the detection of belowground biodiversity hotspots. We investigated the potential for using remotely sensed information about forest structural diversity as a predictor of soil microbial community richness and composition. We calculated LiDAR‐derived metrics of structural diversity as well as a suite of stand and soil properties from 38 forested plots across the central hardwoods region of Indiana, USA, to test whether forest canopy structure is linked with the community richness and diversity of four key soil microbial groups: bacteria, fungi, arbuscular mycorrhizal (AM) fungi, and ectomycorrhizal (EM) fungi. We found that the density of canopy vegetation is positively associated with the taxonomic richness (alpha diversity) of EM fungi, independent of changes in plant taxonomic richness. Further, structural diversity metrics were significantly correlated with the overall community composition of bacteria, EM, and total fungal communities. However, soil properties were the strongest predictors of variation in the taxonomic richness and community composition of microbial communities in comparison with structural diversity and tree species diversity. As remote sensing tools and algorithms are rapidly advancing, these results may have important implications for the use of remote sensing of vegetation structural diversity for management and restoration practices aimed at preserving belowground biodiversity.
Deep phenotyping of p.(V142I)‐associated variant transthyretin amyloid cardiomyopathy: Distinct from wild‐type transthyretin amyloidosis?
Authors: Razvi Yousuf , Ioannou Adam , Patel Rishi K. , Chacko Liza , Karia Nina , Riefolo Mattia , Porcari Aldostefano , Rauf Muhammad Umaid , Starr Neasa , Ganesananthan Sashiananthan , Blakeney Iona , Kaza Nandita , Filisetti Stefano , Bolhuis Roos Eline , Rowczenio Dorota , Gilbertson Janet , Hutt David , Mahmood Shameem , Lachmann Helen J. , Wechalekar Ashutosh D. , Kotecha Tushar , Knight Daniel S. , Coghlan John G. , Petrie Aviva , Whelan Carol J. , Venneri Lucia , Martinez‐Naharro Ana , Hawkins Phillip , Fontana Marianna , Gillmore Julian D.
Published: November 2023

Aims

Transthyretin amyloid cardiomyopathy (ATTR‐CM) is an increasingly recognized cause of heart failure. A total of 3–4% of individuals of African descent carry a TTR gene mutation encoding the p.(V142I) variant, a powerful risk factor for development of variant ATTR‐CM (ATTRv‐CM); this equates to 1.6 million carriers in the United States. We undertook deep phenotyping of p.(V142I)‐ATTRv‐CM and comparison with wild‐type ATTR‐CM (ATTRwt‐CM).

Methods and results

A retrospective study of 413 patients with p.(V142I) ATTRv‐CM who attended the UK National Amyloidosis Centre (NAC) was conducted. Patients underwent evaluation at time of diagnosis, including clinical, echocardiography, and biomarker analysis; a subgroup had cardiac magnetic resonance (CMR) imaging. A total of 413 patients with ATTRwt‐CM, matched for independent predictors of prognosis (age, NAC Stage, decade of first presentation), were used as a comparator group. At time of diagnosis, patients with ATTRv‐CM had significant functional impairment by New York Heart Association classification (NHYA class ≥ III; 38%) and 6‐min walk test distance (median 276 m). Median 5‐year survival in ATTRv‐CM patients was 31 versus 59 months in matched patients with ATTRwt‐CM (p < 0.001). Patients with ATTRv‐CM had significant impairment of functional parameters by echocardiography including biventricular impairment, high burden of regurgitant valvular disease and low cardiac output. Multivariable analysis revealed the prognostic importance of right ventricular dysfunction. CMR and histological analysis revealed myocyte atrophy and widespread myocardial infiltration in ATTRv‐CM.

Conclusion

p.(V142I)‐ATTRv‐CM has an aggressive phenotype characterized by myocyte loss and widespread myocardial infiltration which may account for frequent biventricular failure and poor prognosis in this ATTR‐CM genotypic subgroup.
Activation of Molecular Oxygen and Peroxodisulfate for Removal of Water‐Soluble Antibiotics Using Metal‐Organic Framework‐Derived CoNx@NC Catalyst
Authors: Vyas Ved , Indra Arindam
Published: November 2023

Advanced oxidation process using reactive oxygen species (ROS) can be efficiently utilized to remove soluble contaminants from water. Herein, we have reported a facile method for the activation of molecular oxygen to produce ROS using Prussian blue analog (PBA)‐derived catalyst CoNx@NC. The two‐electron reduction of O2 by CoNx@NC produces H2O2, which is further dissociated into ⋅OH radicals and decomposes water‐soluble organic dye (methylene blue) and antibiotics (ciprofloxacin and amoxicillin). CoNx@NC is capable of removing 98 % of ciprofloxacin in a short period of time (65 minutes) in the presence of oxygen. Further, CoNx@NC can activate peroxodisulfate in the aqueous medium to produce ROS (SO4⋅−, and ⋅OH) and catalyzes the decomposition of the antibiotics and organic dye. The efficiency of the degradation of antibiotics and dye is improved when peroxodisulfate is used for the formation ROS. The higher oxidation potential and longer life‐time of SO4⋅− than ⋅OH improves the rate oxidation with peroxodisulfate. The Co−N coordination in CoNx@NC stabilizes the system against leaching and shows excellent stability for recycling (for five cycles) during the removal of contaminants.
Lacustrine and palustrine carbonates in a Brigantian (late Dinantian) intrashelf basin in the Derbyshire carbonate platform
Authors: Gutteridge Peter
Published: November 2023

The Brigantian (late Dinantian) Headstone Laminite provides a record of freshwater carbonate deposition in an intrashelf basin when the surrounding Derbyshire carbonate platform was emergent. The laminated grainstone/carbonate mudstone facies contains calcified plant material, peloids, ostracods and lenses of calcite tufa deposited in a lake margin and sublittoral part of a freshwater lake in a humid palaeoclimate. Precipitation of tufa may have taken place along water courses or resurgences fed by meteoric run‐off and seepage from the karsted carbonate platform. The fenestral carbonate mudstone with calcrete and fenestrae represent deposition in well‐drained parts of the lake margin. A shift to more arid conditions is represented by the laminated dolomudstone facies with an allochem assemblage of calcified plants and micropeloidal dolomicrospar grains and occasional alginite in restricted a lake basin setting. Gypsum crystals and desiccation curls are also present in evaporitic lake margin settings. A return to more humid conditions is indicated by deposition of the laminated grainstone/carbonate mudstone facies with organic‐rich mudstone with thin coal seams and carbonized roots deposited in a poorly drained lake margin setting. This may be a reflection of a gradual transgression after emergence. The eastern margin of the intrashelf basin may have been formed by the Edensor Anticline; however, it is not known if a further complex of lacustrine, palustrine and lagoonal facies was present to the east. Deposition of graded beds containing lithoclasts derived from lacustrine facies were associated with slumping generated by reactivation of structures controlling the intrashelf basin margins.
Neuroplastic changes in functional wiring in sensory cortices of the congenitally deaf: A network analysis
Authors: Ruttorf Michaela , Tal Zohar , Amaral Lénia , Fang Fang , Bi Yanchao , Almeida Jorge
Published: November 2023

Congenital sensory deprivation induces significant changes in the structural and functional organisation of the brain. These are well‐characterised by cross‐modal plasticity, in which deprived cortical areas are recruited to process information from non‐affected sensory modalities, as well as by other neuroplastic alterations within regions dedicated to the remaining senses. Here, we analysed visual and auditory networks of congenitally deaf and hearing individuals during different visual tasks to assess changes in network community structure and connectivity patterns due to congenital deafness. In the hearing group, the nodes are clearly divided into three communities (visual, auditory and subcortical), whereas in the deaf group a fourth community consisting mainly of bilateral superior temporal sulcus and temporo‐insular regions is present. Perhaps more importantly, the right lateral geniculate body, as well as bilateral thalamus and pulvinar joined the auditory community of the deaf. Moreover, there is stronger connectivity between bilateral thalamic and pulvinar and auditory areas in the deaf group, when compared to the hearing group. No differences were found in the number of connections of these nodes to visual areas. Our findings reveal substantial neuroplastic changes occurring within the auditory and visual networks caused by deafness, emphasising the dynamic nature of the sensory systems in response to congenital deafness. Specifically, these results indicate that in the deaf but not the hearing group, subcortical thalamic nuclei are highly connected to auditory areas during processing of visual information, suggesting that these relay areas may be responsible for rerouting visual information to the auditory cortex under congenital deafness.
Spatiotemporal distribution of precipitation and its characteristics under tropical atmospheric systems of Brazil: Insights from a large sub‐hourly database
Authors: Lemos Filipe C. , Coelho Victor Hugo R. , Freitas Emerson da S. , Tomasella Javier , Bertrand Guillaume F. , Meira Marcela A. , Filho Geraldo M. Ramos , Fullhart Andrew , Almeida Cristiano das N.
Published: November 2023

The study of rainfall properties at various spatiotemporal scales is deeply important for understanding a large range of socio‐environmental processes and variables (e.g., water resources, agriculture, socio‐ecosystemic services, natural risk assessment). However, such studies on rainfall characteristics, especially at sub‐hourly resolutions, are scarce in large areas of South America due to the lack of a high‐resolution temporal database. The Brazilian National Centre for Monitoring and Early Warning of Natural Disasters (CEMADEN) has gradually implemented, starting in 2013, a sub‐hourly monitoring network composed of approximately 3500 automated rain gauges distributed across Brazil, enabling access to new hydrological studies in this vast tropical country featuring a range of biomes. This study analysed the characteristics of rainfall events for the whole of Brazil on sub‐daily and sub‐hourly timescales, using 7 years of data (from 2014 to 2021) provided by CEMADEN. Rainfall events were defined by the minimum inter‐event time (MIT) and the minimum depth (1 mm). Seven MITs (30, 60, 120, 180, 360, 720, and 1440 min) were considered to evaluate the behaviour of rainfall event characteristics and their relationships. The Gaussian mixture model method was applied to identify regions with similar rainfall patterns according to the MIT. Six groups with homogeneous characteristics were identified, evidencing the climatic diversity of Brazil. The results show that the MIT strongly influences precipitation properties (especially the dry time and the number of events). The highest number of events occurred in the North‐east Coast region, which exceeded 200 events per year (MIT < 60 min), while the lowest number of events was observed in the Semiarid region, which reached only 38 events per year with an MIT of 1440 min. Moreover, the events with the highest rainfall intensities were found in the Central region. The results found in this study provide a better understanding of precipitation and its characteristics in Brazil, highlighting the climatological diversity of this country.
A case of unilateral sclerosing stromal tumor of the ovary in a postmenopausal female
Authors: Gao Chao , Han Yanyan , Fan Xiangqin , Dong Haiwei , Xue Fengxia , Wang Yingmei
Published: November 2023

Synopsis

Although SSTs predominantly affect young women, postmenopausal women with pelvic masses should not be overlooked. A comprehensive approach is necessary for diagnosis of this tumor.