bluuebunny/crossref_metadata_2025 huggingface dataset:
Wirbelsäulennahe Injektionstherapie im Sport
Authors: Veihelmann Andreas
Published: February 2019

Wirbelsäulennahe Injektionen werden bei unterschiedlichen spezifischen Ursachen für akuten oder auch chronischen Rücken- und/oder Beinschmerz beim Sportler durchgeführt. Auch wenn diese Injektionen in zahlreichen Leitlinien als Teil der konservativen Therapie implementiert sind, werden diese nach wie vor kontrovers diskutiert. Gerade im Sport rückt die konservative Therapie inklusive wirbelsäulennahe Injektionen in den Focus von Wissenschaft und Forschung. In diesem Artikel werden die unterschiedlichen Formen der bildgesteuerten Injektionstechniken an der Wirbelsäule als schmerztherapeutische Maßnahmen beschrieben und in ihrer Wirksamkeit beleuchtet. Lokale Injektionen der Facettengelenke beim Facettensyndrom und der Bandscheiben beim diskogenen Schmerz scheinen einen eher kurzfristigen Effekt zu haben, während epidurale Injektionen bei Diskusprolaps und/oder epiduraler Fibrose nach Wirbelsäulenoperationen (Postnukleotomie-Syndrom) eine sinnvolle Unterstützung bei der konservativen Therapie sein können. Beim Facettensyndrom scheint die Denervation mittels Radiofrequenz eine effektive Behandlungsmethode für eine kurz- bis mittelfristige Besserung darzustellen. Daneben haben auch Pars-Injektionen beim Pars-interarticularis-Ödem sowie Injektionen beim Sakroiliakalgelenks-Syndrom ihren Stellenwert. Die Medikamente und das Steroidpräparat für wirbelsäulennahe Injektionen müssen sorgfältig ausgewählt werden und werden in Deutschland teilweise als off-label-use eingesetzt, worüber der Patient aufgeklärt werden muss und nicht zu Lasten der gesetzlichen Krankenkassen abgerechnet werden darf.
Review of Health Problems in Adult Patients with Classic Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency
Authors: Reisch Nicole
Published: February 2019

The introduction of newborn screening programmes in most Western countries for classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH) enables timely introduction of life-saving glucocorticoid replacement in affected babies. Early diagnosis and optimised pediatric care not only successfully led to survival but also allow that almost all patients reach adulthood. Cohort studies in adults, however, provided evidence for significant health problems and co-morbidities of adult patients such as life-threatening adrenal crises, cardiovascular and metabolic health problems, fertility problems, benign endocrine tumours, and osteopenia and osteoporosis. This review summarises the current state of knowledge aiming to emphasize the neccessity of primary and secondary prevention of additional long-term health issues as a major task of health professionals in the care of CAH.
Patientenmotivation zur Mitwirkung in verschiedenen Unterrichts- und Lehrmodalitäten der medizinischen Aus- und Weiterbildung
Authors: Lucas Benjamin , Wiegand Stefan , Jahn Oliver , Greiner Felix , Walcher Felix , Piatek Stefan
Published: February 2019

Hintergrund Der studentische Unterricht fokussiert zunehmend auf eine fallbasierte Lehre. Dabei wird häufig als selbstverständlich vorausgesetzt, dass sich Patienten für die studentische Ausbildung zur Verfügung stellen. Eine anonymisierte Patientenumfrage sollte daher die Bereitschaft der Patienten zur Mitwirkung an der medizinischen Lehre ermitteln und die verschiedenen Einflussfaktoren untersuchen.

Material und Methoden Die Umfrage erfolgte unter stationären Patienten einer unfallchirurgischen Universitätsklinik mittels Fragebogen im Zeitraum vom 01.01.2017 bis 30.04.2017. Sie beinhaltete 10 Auswahlfragen zu soziodemografischen Daten und zur Bereitschaft, in verschiedenen Aus- und Weiterbildungsprogrammen mitzuwirken. Abgefragt wurde mittels 5-stufiger Likert-Skala, die elektronische Auswertung erfolgte mit der Scannerkorrektur-Software KLAUS (Firma Blubbsoft GmbH, Berlin, Deutschland).

Ergebnisse 162 Fragebögen konnten vollständig ausgewertet werden. Insgesamt wurde eine hohe Motivation für die Mitwirkung am Unterricht am Krankenbett (UaK) und an studentischen Prüfungen sowie zur Freigabe von Röntgenbildern, Fotos und Videos als auch für eine spätere Kontaktaufnahme zu Lehrzwecken festgestellt. Ein Motivationsfaktor war die Patientenzufriedenheit, die in einer positiven Korrelation zu UaK, studentischer Prüfung, Freigabe von Röntgenbildern, Fotos und Videos sowie späterer Kontaktaufnahme stand. Für die Mitwirkung an einer Vorlesung bestand eine signifikant geringere Motivation. Männer zeigten dabei eine signifikant höhere Motivation als Frauen. 40- bis 49-jährige Patienten zeigten eine signifikant geringere Motivation als 20- bis 29-jährige und 50- bis 59-jährige Patienten. Die Patientenzufriedenheit hatte keinen relevanten Einfluss auf die Motivation zur Mitwirkung an einer Vorlesung.

Schlussfolgerung Die Motivation von Patienten zur Mitwirkung an der Lehre sowie zur Freigabe von Röntgenbildern, Fotos und Videos korreliert mit der Patientenzufriedenheit. Soziodemografische Faktoren spielen eine untergeordnete Rolle. Zur Mitwirkung an einer Vorlesung besteht unabhängig von der Patientenzufriedenheit generell eine geringere Motivation.
Vergleich offener Wundheilungsverfahren beim
Hund
Authors: Albert Rebecca
Published: February 2019

Nolff MC, Albert R, Reese S, Meyer-Lindenberg A. Comparison of negative pressure
wound therapy and silver-coated foam dressings in open wound treatment in dogs:
a prospective controlled clinical trial. Vet Comp Orthop Traumatol 2018; 31 (4):
229–238.

Die vakuumassistierte Wundtherapie (Negative Pressure Wound Therapy, NPWT) hat
in den letzten Jahren in der Kleintiermedizin starken Einzug gehalten. In
einer prospektiven Studie wurde dieses Verfahren mit der Anwendung eines
silberbeschichteten Wundkissens hinsichtlich Wundheilungsrate, bakterieller
Besiedelung der Wunde und möglicher Komplikationen verglichen.
Diabetes und Herzinsuffizienz
Authors: Schütt Katharina , Marx Nikolaus
Published: February 2019

Die Bedeutung des Vorliegens einer Herzinsuffizienz bei Patienten mit Diabetes ist lange Zeit unterschätzt worden. Daten der letzten Jahre konnten zeigen, dass Menschen mit Diabetes ein hohes Risiko haben, eine Herzinsuffizienz zu entwickeln und dass diese Situation einer schlechten Prognose assoziiert ist. Der folgende Artikel gibt eine Übersicht über den Erkenntnisstand zur Inzidenz und der Prognose von Herzinsuffizienz und Diabetes und legt einen Fokus auf die mitunter schwierige Diagnostik einer Herzinsuffizienz in dieser Hochrisikopopulation.
Mikronährstoffe in der Onkologie: Risiko und Nutzen
Authors: Mücke Ralph , Micke Oliver , Büntzel Jens
Published: February 2019

Hintergrund: Das Interesse sowohl von betreuenden Ärzten als auch Tumorpatienten an der zusätzlichen Einnahme von Mikronährstoffen während einer onkologischen Therapie mit unterschiedlichen Intentionen nimmt zu. Dieses Update liefert deshalb eine Standortbestimmung zum zusätzlichen Einsatz von ausgewählten Mikronährstoffen während der Tumortherapie.

Methoden: Es wurde eine Literaturrecherche hinsichtlich des Einsatzes von ausgewählten Mikronährstoffen in der Onkologie, die bis 2017 in zitierfähigen Journalen erschienen sind, durchgeführt.

Ergebnisse: Daten zu Mikronährstoffen, die sowohl hinsichtlich der Lebensqualität als auch der Prognose einen Nutzen für onkologische Patienten bringen, als auch Erkenntnisse zu Mikronährstoffen, die für die Patienten keinen Benefit haben oder sogar schaden, werden präsentiert. Die gute Datenlage hinsichtlich Vitamin D und Selen erlaubt hier die Empfehlung zur Supplementation nach Spiegelbestimmung im Serum.

Schlussfolgerung: Nicht nur vorrangig onkologisch tätige Ärzte, sondern auch alle Ärzte, die Tumorpatienten mitbetreuen, sollten Kenntnisse über die wichtigsten Mikronährstoffe haben, um diese an die Patienten weiterzugeben und sie auch gezielt zum Nutzen der Patienten einzusetzen.
Vorsicht: Interaktionen!
Authors: Ritter Christoph A. , Höckel Michael
Published: February 2019

Über 40–50 % der Krebspatienten wenden komplementäre und alternative Medizin (KAM) an, Frauen mit gynäkologischen Tumoren noch deutlich häufiger. In der Laienpresse werden die sogenanntennatürlichen Therapien beworben und viele Patienten nehmen die Ratschläge dankbar auf. Eine aktuell veröffentlichte Auswertung zeigt, dass eine alleinige alternative Behandlung für das Gesamtüberleben nachteilig ist. Die Herausforderung ist daher, die Patienten mit Wunsch nach KAM-Produkten kompetent aus ärztlicher und pharmazeutischer Sicht zu begleiten, um Vorteile wie z. B. die Reduzierung von Nebenwirkungen zu ermöglichen und aber die Nachteile wie die Beeinträchtigung der leitliniengerechten Therapie durch z. B. Interaktionen zwischen Phytotherapeutika und Arzneimitteln zu verhindern. Die Anzahl der Untersuchungen in Bezug auf mögliche Interaktionen nimmt nur langsam zu. Erste Ansätze zeigen aber, dass es mittels Befragung von Krebspatienten und Ärzten zumindest gelingt, die häufig verwendeten Pflanzen bzw. Pflanzeninhaltsstoffe einzugrenzen. Aufgrund der bestehenden Kenntnisse in Bezug auf die jeweiligen pharmakodynamischen und -kinetischen Eigenschaften kann dann zumindest theoretisch dasInteraktionspotential in Form von Risikoevaluationstools odereinfachen Übersichten aufgezeigt werden.
Naturheilverfahren in der Gynäkologie
Authors: Osorio Birthe , Brandt Andreas , Münstedt Karsten
Published: February 2019

Zu Naturheilverfahren im eigentlichen Sinn zählen Ernährung, Bewegung, Entspannung, die Nutzung von Wasser, Licht, Kälte und Wärme, sowie pflanzliche Mittel. Die klassische Naturheilkunde beinhaltet damit die Phytotherapie, die Hydrotherapie, die Bewegungstherapie, die Ernährungstherapie und die Ordnungstherapie. Mit diesen Naturheilverfahren lassen sich Krankheiten verhindern, heilen oder lindern. Sie können auch zur Unterstützung verschiedener Formen schulmedizinischer Therapien gegeben werden. Allerdings lässt die Datenlage in diesem Bereich aufgrund des Mangels an klinischen Studien mit Naturheilverfahren noch zu wünschen übrig und es gibt verhältnismäßig wenige evidenzbasierte Daten. Bei manchen Krankheitsbildern, wie z. B. Dysmenorrhoe, Uterus myomatosus, Menopausenbeschwerden, Endometriose und Inkontinenz können Naturheilverfahren für niedergelassene Gynäkologen sehr interessant sein.
Therapie der Herzinsuffizienz bei Diabetes
Authors: Kraus Bettina J. , Frantz Stefan
Published: February 2019

Die Herzinsuffizienz mit eingeschränkter systolischer (HFrEF) bzw. diastolischer (HFpEF) Pumpfunktion ist eine häufige und klinisch relevante Begleiterkrankung bei Patienten mit Diabetes. Diabetiker haben ein etwa doppelt so hohes Risiko für das Auftreten einer Herzinsuffizienz und ein 2- bis 4-fach erhöhtes Risiko für die Notwendigkeit von Krankenhausaufenthalten wegen Herzinsuffizienz als Nicht-Diabetiker. Auch die Prognose wird durch das gemeinsame Auftreten beider Erkrankungen deutlich verschlechtert: die Mortalität bei herzinsuffizienten Diabetikern ist etwa 1,5-fach erhöht im Vergleich zu Nicht-Diabetikern mit Herzinsuffizienz.

Eine frühe Diagnosestellung ist essentiell, insbesondere bei HFpEF, da bisher die Vorbeugung die einzige Maßnahme ist, die die Prognose der Patienten verbessern kann. Entscheidend ist die Äußerung des klinischen Verdachts, der dann mittels Echokardiographie und (NT-pro-)BNP-Messung erhärtet werden kann. Therapeutisch stehen vor allem die Einstellung der Risikofaktoren Blutdruck und Blutzucker, sowie eine regelmäßige, individualisierte körperliche Bewegung im Vordergrund. Eine leitliniengerechte Herzinsuffizienztherapie bei HFrEF unterscheidet sich beim Diabetiker nicht wesentlich vom Nicht-Diabetiker. ACE-Hemmer, Betablocker, Mineralokortikoid-Rezeptor-Antagonisten und bei Bedarf auch ARNI (Angiotensin-Rezeptor-Neprilysin-Inhibitor) sowie Ivabradin senken Mortalität und Hospitalisierungsraten. Und auch die medikamentöse Therapie des Diabetes besteht im Wesentlichen aus den Basismaßnahmen, Metformin als Mittel der 1. Wahl, sowie SGLT2-Inhibitoren und GLP-1-Agonisten in der Add-On-Therapie. Lediglich auf den Einsatz von Insulin-Sensitizern sollte bei Patienten mit Herzinsuffizienz unbedingt verzichtet werden.

Neue therapeutische Ansätze zeigen, dass Herzinsuffizienz und Diabetes möglicherweise gemeinsame Pathomechanismen teilen und daher erfolgreich gemeinsam therapiert werden können. Subgruppen-Analysen der vorhandenen Studien lassen auf einen zusätzlichen Nutzen auch bei Patienten mit der jeweils komplementären Erkrankung hoffen, letztlich muss die Wirksamkeit von SGLT2-Inhibitoren bei Patienten ohne Diabetes jedoch in randomisierten Studien erst noch unter Beweis gestellt werden. Die Ergebnisse dieser Outcome-Studien werden in den kommenden 2 Jahren erwartet.
Potenziale des Dritten Sozialmedizinischen Panels für Erwerbspersonen (SPE-III) für die Forschung im Bereich Migration und Rehabilitation: Das Beispiel der Inanspruchnahme rehabilitativer Versorgung
Authors: Brzoska Patrick , Spanier Katja , Bethge Matthias
Published: February 2019

Ziel der Studie Die Mehrzahl bisheriger Studien zeigt, dass Menschen mit Migrationshintergrund die medizinische Rehabilitation seltener als Menschen ohne Migrationshintergrund nutzen. Teilweise werden jedoch auch gegensätzliche Ergebnisse berichtet. Bisherige Untersuchungen haben unterschiedliche Limitationen. Die vorliegende Studie untersucht die Inanspruchnahme von Rehabilitation bei Menschen mit und ohne Migrationshintergrund auf Basis des Dritten Sozialmedizinischen Panels für Erwerbspersonen (SPE-III).

Methodik Die Auswertung basiert auf der ersten Erhebungswelle des SPE-III, erweitert um administrative Daten aus den Versicherungskonten der jeweiligen Studienteilnehmerinnen und -teilnehmer. Die Befragung wurde im Mai 2013 durchgeführt und umfasst eine Risikokohorte von in ihrer Teilhabe gefährdeten Versicherten der Deutschen Rentenversicherung Bund mit Krankengeldbezug im Jahr 2012. Es wird zwischen ausländischen Staatsangehörigen, deutschen Staatsangehörigen mit und deutschen Staatsangehörigen ohne Migrationshintergrund unterschieden. Als Kovariaten wurden in Anlehnung an das Andersen Healthcare Utilization Model die Lebensqualität, die subjektive Gefährdung der Erwerbsfähigkeit sowie demografische und sozioökonomische Faktoren über ein logistisches Regressionsmodell berücksichtigt.

Ergebnisse Von den 2413 eingeschlossenen Befragten waren 2,7% ausländische Staatsangehörige und 4,4% deutsche Staatsangehörige mit Migrationshintergrund. Die Inanspruchnahme von Rehabilitation unterschied sich bei Deutschen mit Migrationshintergrund und ausländischen Staatsangehörigen nicht signifikant von der Inanspruchnahme bei Deutschen ohne Migrationshintergrund (adjustiertes Odds Ratio=0,78; 95%-CI=0,47–1,30 bzw. adjustiertes Odds Ratio=0,99; 95%-CI=0,53–1,88).

Schlussfolgerungen Durch die detaillierte Erfassung des Migrationshintergrundes, die Möglichkeit, Einflussfaktoren auf unterschiedlichen Ebenen zu berücksichtigen sowie die Verknüpfbarkeit von Befragungsdaten mit Routinedaten erlaubt es das SPE-III, einige Limitation früherer Studien zu überwinden. Die Ergebnisse stehen im Widerspruch zur Mehrheit dieser Studien und machen damit deutlich, dass die versorgungsepidemiologische Studienlage zur Inanspruchnahme rehabilitativer Versorgung bei Menschen mit Migrationshintergrund insgesamt inkonsistent ist. Bei der Interpretation der vorliegenden Ergebnisse müssen auch der besondere Zuschnitt des SPE-III sowie die vergleichsweise geringe Fallzahl berücksichtigt werden.
A Free-Radical and Protecting-Group-Free Approach to (–)-Boschnialactone and γ-Lycorane
Authors: Basante-Avendaño Alberto , Guerra-Ayala Víctor , Sánchez-Eleuterio Alma , Cordero-Vargas Alejandro
Published: February 2019

The protecting-group-free (PGF) and free-radical-based synthesis of two structurally different natural products, (–)-boschnialactone and γ-lycorane, is reported. The key step in both syntheses is a radical–ionic sequence for construction of the principal structure (a six-membered lactone and a 1,4-dicarbonyl compound, respectively), allowing short and rapid access to these natural products through a PGF route.
POLAR Diversion: Using General Practice Data to Calculate Risk of Emergency Department Presentation at the Time of Consultation
Authors: Pearce Christopher , McLeod Adam , Rinehart Natalie , Patrick Jon , Fragkoudi Anna , Ferrigi Jason , Deveny Elizabeth , Whyte Robin , Shearer Marianne
Published: February 2019

Objective This project examined and produced a general practice (GP) based decision support tool (DST), namely POLAR Diversion, to predict a patient's risk of emergency department (ED) presentation. The tool was built using both GP/family practice and ED data, but is designed to operate on GP data alone.

Methods GP data from 50 practices during a defined time frame were linked with three local EDs. Linked data and data mapping were used to develop a machine learning DST to determine a range of variables that, in combination, led to predictive patient ED presentation risk scores. Thirteen percent of the GP data was kept as a control group and used to validate the tool.

Results The algorithm performed best in predicting the risk of attending ED within the 30-day time category, and also in the no ED attendance tests, suggesting few false positives. At 0 to 30 days the positive predictive value (PPV) was 74%, with a sensitivity/recall of 68%. Non-ED attendance had a PPV of 82% and sensitivity/recall of 96%.

Conclusion Findings indicate that the POLAR Diversion algorithm performed better than previously developed tools, particularly in the 0 to 30 day time category. Its utility increases because of it being based on the data within the GP system alone, with the ability to create real-time “in consultation” warnings. The tool will be deployed across GPs in Australia, allowing us to assess the clinical utility, and data quality needs in further iterations.
A short characterization of relative entropy
Authors: Leinster Tom
Published: February 2019

We prove characterization theorems for relative entropy (also known as Kullback–Leibler divergence), q-logarithmic entropy (also known as Tsallis entropy), and q-logarithmic relative entropy. All three have been characterized axiomatically before, but we show that earlier proofs can be simplified considerably, at the same time relaxing some of the hypotheses.
On computing spectral densities from classical, semiclassical, and quantum simulations
Authors: Gottwald Fabian , Ivanov Sergei D. , Kühn Oliver
Published: February 2019

The Caldeira-Leggett model provides a compact characterization of a thermal environment in terms of a spectral density function, which has led to a variety of numerically exact quantum methods for reduced density matrix propagation. Since spectral densities are often computed from classical molecular dynamics simulations, we investigate in this paper whether quantum effects should be accounted for in the calculations. Therefore, we reformulate the recently developed Fourier method for spectral density calculations from semiclassical simulations which approximately allow for quantum effects. We propose two possible protocols based on either correlation functions or expectation values. These protocols are tested on a generic Calderra-Leggett model for the linearized semiclassical initial-value representation (LSC-IVR), the thawed Gaussian wave packet dynamics (TGWD), and hybrid schemes combining the two with the more accurate Herman-Kluk formula. Surprisingly, spectral densities from the LSC-IVR method, which treats the dynamics completely classically, are found to be extremely accurate, even in the quantum regime, where this method does not give a correct description of the correlation functions and expectation values. In contrast, the TGWD method turns out as too inaccurate for spectral density calculations, and the hybrid schemes perform well only if the system is close to the classical regime. This implies that, if the bath has a Caldeira-Leggett form, spectral densities are insensitive to quantum effects and any effort to approximately account for them rather leads to errors. Hence, in this case, spectral densities can be computed from classical simulations and used in a reduced quantum simulation as well.
Thermally tunable asymmetric metamolecule
Authors: Li Haohua , Wang Xiaobo , Zhou Ji
Published: February 2019

The Mie resonance of two dielectric meta-atoms causes a destructive coupling effect between them and results in hybridization induced transparency in the metamolecule. By actively adjusting the temperature, permittivities of the dielectric with opposite temperature coefficients vary in contrary trends, appearing as the field redistribution in each meta-atom. At the same time, two collective modes of the metamolecule behave as addition and subtraction of magnetic fields in meta-atoms. Combining both the intrinsic properties of materials and the collective properties of the coupling “dimer” system together, varying degrees of asymmetry of the metamolecule are obtained as the temperature changes. Since the intensity of the excited magnetic field can reflect the resonance amplitudes of the metamolecule onto the incident wave, the ratio of the transmission amplitudes of the two collective modes changes in a manner similar to the average magnetic field intensity of the metamolecule in two hybridized modes. Based on this behavior, we propose a method to estimate the degree of asymmetry of the metamolecule according to the field distribution intensity.
Influence of plasma channel impedance model on electrohydraulic shockwave simulation
Authors: Liu Si-Wei , Liu Yi , Ren Yi-Jia , Lin Fu-Chang , Liu Yang , Shen Yin-Kuo
Published: February 2019

The simulation of electrohydraulic shockwaves is the key technology for their application and device design. The analytical approach of underwater pulsed discharge is described using the dimensionless analysis method, which combines energy based hydrodynamic equations and the electrical differential equation describing the discharge characteristics of the circuit. A constant plasma channel impedance model based on the experimental results and an improved time-varying plasma channel impedance model based on the Braginskii equation are proposed and presented. The plasma channel impedance has a great influence on the deposited energy into the plasma channel and then affects the calculation and analysis of the shockwave propagation. The electrical characteristics and fluid physical properties are taken into consideration, and the results are compared. The application range of different impedance models is summarized, and the time-varying impedance model can provide a more accurate result in the simulation of shockwave propagation. The dimensionless analysis method, together with a time-varying impedance model, could be a useful tool for evaluation of the electrohydraulic shockwave in practical applications and applied physics research of underwater spark discharge.
Anomalous temperature dependence of Al2O3/SiO2 and Y2O3/SiO2 interface dipole layer strengths
Authors: Nittayakasetwat Siri , Kita Koji
Published: February 2019

The temperature dependences of the dipole layer strength at Al2O3/SiO2 and Y2O3/SiO2 interfaces were investigated. The dipole layer strength at each temperature was quantified from the flatband voltage (Vfb) shift of metal-oxide-semiconductor capacitors with Al2O3/SiO2 and Y2O3/SiO2 bilayer gate dielectrics on Si substrates. In order to accurately extract the dipole layer strength, the effects of the difference between the gate metal work function and the Si Fermi level, the fixed charges at the SiO2/Si interface, and the fixed charges at the high-k/SiO2 interface on the Vfb shift were excluded. It was found that both interface dipole layer strengths increased but in the opposite direction at the approximated rates of +2.2 mV K−1 and −0.7 mV K−1 for Al2O3/SiO2 and Y2O3/SiO2 interfaces, respectively, when the temperature was raised from 100 K to 300 K. The temperature dependences are larger than expected if only the thermal expansion of the oxides was considered as the factor which changes the effective dipole length of the dipole layers.
Engineering thermal and electrical interface properties of phase change memory with monolayer MoS2
Authors: Neumann Christopher M. , Okabe Kye L. , Yalon Eilam , Grady Ryan W. , Wong H.-S. Philip , Pop Eric
Published: February 2019

Phase change memory (PCM) is an emerging data storage technology; however, its programming is thermal in nature and typically not energy-efficient. Here, we reduce the switching power of PCM through the combined approaches of filamentary contacts and thermal confinement. The filamentary contact is formed through an oxidized TiN layer on the bottom electrode, and thermal confinement is achieved using a monolayer semiconductor interface, three-atom thick MoS2. The former reduces the switching volume of the phase change material and yields a 70% reduction in reset current versus typical 150 nm diameter mushroom cells. The enhanced thermal confinement achieved with the ultra-thin (∼6 Å) MoS2 yields an additional 30% reduction in switching current and power. We also use detailed simulations to show that further tailoring the electrical and thermal interfaces of such PCM cells toward their fundamental limits could lead up to a sixfold benefit in power efficiency.
Understanding the charge transport mechanisms through ultrathin SiOx layers in passivated contacts for high-efficiency silicon solar cells
Authors: Kale Abhijit S. , Nemeth William , Guthrey Harvey , Kennedy Ellis , Norman Andrew G. , Page Matthew , Al-Jassim Mowafak , Young David L. , Agarwal Sumit , Stradins Paul
Published: February 2019

We report on the microscopic structure of the SiOx layer and the transport mechanism in polycrystalline Si (poly-Si) passivated contacts, which enable high-efficiency crystalline Si (c-Si) solar cells. Using electron beam induced current (EBIC) measurements, we accurately map nanoscale conduction-enabling pinholes in 2.2 nm thick SiOx layers in a poly-Si/SiOx/c-Si stack. These conduction enabling pinholes appear as bright spots in EBIC maps due to carrier transport and collection limitations introduced by the insulating 2.2 nm SiOx layer. Performing high-resolution transmission electron microscopy at a bright spot identified with EBIC reveals that conduction pinholes in SiOx can be regions of thin tunneling SiOx rather than a geometric pinhole. Additionally, selectively etching the underlying poly-Si layer in contacts with 1.5 and 2.2 nm thick SiOx layers using tetramethylammonium hydroxide results in pinhole-like etch features in both contacts. However, EBIC measurements for a contact with a thinner, 1.5 nm SiOx layer do not reveal pinholes, which is consistent with uniform tunneling transport through the 1.5 nm SiOx layer. Finally, we theoretically show that reducing the metal to the c-Si contact size from microns, like in the p-type passivated emitter rear contact, to tens of nanometers, like in poly-Si contacts, allows lowering of the unpassivated contact area by several orders of magnitude, thus resulting in excellent passivation, as has been demonstrated for these contacts.
Vibrational analysis of methyl cation—Rare gas atom complexes: CH3+—Rg (Rg = He, Ne, Ar, Kr)
Authors: Meisner Jan , Hallmen Philipp P. , Kästner Johannes , Rauhut Guntram
Published: February 2019

The vibrational spectra of simple CH3+—Rg (Rg = He, Ne, Ar, Kr) complexes have been studied by vibrational configuration interaction theory relying on multidimensional potential energy surfaces (PESs) obtained from explicitly correlated coupled cluster calculations, CCSD(T)-F12a. In agreement with experimental results, the series of rare gas atoms leads to rather unsystematic results and indicates huge zero point vibrational energy effects for the helium complex. In order to study these sensitive complexes more consistently, we also introduce configuration averaged vibrational self-consistent field theory, which is a generalization of standard vibrational self-consistent field theory to several configurations. The vibrational spectra of the complexes are compared to that of the methyl cation, for which corrections due to scalar-relativistic effects, high-order coupled-cluster terms, e.g., quadruple excitations, and core-valence correlation have explicitly been accounted for. The occurrence of tunneling splittings for the vibrational ground-state of CH3+—He has been investigated on the basis of semiclassical instanton theory. These calculations and a direct comparison of the energy profiles along the intrinsic reaction coordinates with that of the hydronium cation, H3O+, suggest that tunneling effects for vibrationally excited states should be very small.
Path-integral methodology and simulations of quantum thermal transport: Full counting statistics approach
Authors: Kilgour Michael , Agarwalla Bijay Kumar , Segal Dvira
Published: February 2019

We develop and test a computational framework to study heat exchange in interacting, nonequilibrium open quantum systems. Our iterative full counting statistics path integral (iFCSPI) approach extends a previously well-established influence functional path integral method, by going beyond reduced system dynamics to provide the cumulant generating function of heat exchange. The method is straightforward; we implement it for the nonequilibrium spin boson model to calculate transient and long-time observables, focusing on the steady-state heat current flowing through the system under a temperature difference. Results are compared to perturbative treatments and demonstrate good agreement in the appropriate limits. The challenge of converging nonequilibrium quantities, currents and high order cumulants, is discussed in detail. The iFCSPI, a numerically exact technique, naturally captures strong system-bath coupling and non-Markovian effects of the environment. As such, it is a promising tool for probing fundamental questions in quantum transport and quantum thermodynamics.
X-ray reflectivity with a twist: Quantitative time-resolved X-ray reflectivity using monochromatic synchrotron radiation
Authors: Joress Howie , Arlington Shane Q. , Weihs Timothy P. , Brock Joel D. , Woll Arthur R.
Published: February 2019

We have developed an improved method of time-resolved x-ray reflectivity (XRR) using monochromatic synchrotron radiation. Our method utilizes a polycapillary x-ray optic to create a range of incident angles and an area detector to collect specular reflections. By rotating the sample normal out of the plane of the incident fan, we can separate the surface diffuse scatter from the reflectivity signal, greatly improving the quality of the XRR spectra compared to previous implementations. We demonstrate the time-resolved capabilities of this system, with the temporal resolution as low as 10 ms, by measuring XRR during the annealing of Al/Ni nano-scale multilayers, and use this information to extract the activation energy for interdiffusion in this system.
Droplet generation at Hele-Shaw microfluidic T-junction
Authors: Chakraborty I. , Ricouvier J. , Yazhgur P. , Tabeling P. , Leshansky A. M.
Published: February 2019

We proposed the combined numerical and experimental study of the dynamics of droplets generation at shallow microfluidic T-junction, where the flow is strongly confined in the vertical direction. The numerical simulation is performed by employing quasi-2D Hele-Shaw approximation with an interface capturing procedure based on coupled Level-Set and Volume-of-Fluid methods. We investigate the effect of the capillary number, Ca, the channel geometry (cross section aspect ratio, χ), and the flow rate (disperse-to-continuous phases) ratio, Γ, on the dynamics of the droplet breakup. Depending on Ca, three distinct flow regimes are identified: squeezing, tearing and jetting. In the squeezing regime at low Ca, the size of the generated droplets depends on χ and Γ, while it is almost insensitive to Ca in agreement to previous studies. In the tearing regime at moderate Ca, the droplet size decreases as ∼Ca−1/3, while it is only a weak function of χ and Γ. Finally, in the jetting regime, the steady co-flow of both phases takes place at high enough Ca. The numerical predictions based on the Hele-Shaw flow approximation are in excellent agreement with our in-house experimental results, demonstrating that the proposed approach can be effectively used for computationally inexpensive and adequately accurate modeling of biphasic flows in shallow microfluidic devices.
Folded alkane chains and the emergence of the lamellar crystal
Authors: Shakirov T. , Paul W.
Published: February 2019

The competition between chain stiffness and chain collapse gives rise to complex low temperature morphologies of single polymer chains, in our case alkanes. These structures are characterized by specific sequences of dihedral angles along the chain, i.e., dihedral angle correlations extending beyond local steric effects. To describe and classify these morphologies, one can transfer concepts from protein science, where this creation of dihedral angle correlations underlies the formation of α-helices and β-sheets. We show here by means of flat-histogram Monte Carlo simulations that, although lacking in primary structure being simple homopolymers, short alkane chains fold into non-trivial ground states (tertiary structure) consisting of chain segments of defined secondary structures. The folded lamellar crystal typical for polyethylene chains requires a minimum chain length to occur as the ground state folded structure, which we identify to be around 150 repeat units.
Surface van der Waals forces in a nutshell
Authors: MacDowell Luis G.
Published: February 2019

Most often in chemical physics, long range van der Waals surface interactions are approximated by the exact asymptotic result at vanishing distance, the well known additive approximation of London dispersion forces due to Hamaker. However, the description of retardation effects that is known since the time of Casimir is completely neglected for the lack of a tractable expression. Here we show that it is possible to describe surface van der Waals forces at arbitrary distances in one single simple equation. The result captures the long sought crossover from non-retarded (London) to retarded (Casimir) interactions, the effect of polarization in condensed media, and the full suppression of retarded interactions at large distance. This is achieved with similar accuracy and the same material properties that are used to approximate the Hamaker constant in conventional applications. The results show that at ambient temperature, retardation effects significantly change the power law exponent of the conventional Hamaker result for distances of just a few nanometers.
Using isothermal-isobaric Monte Carlo simulation to study the wetting behavior of model systems
Authors: Jain Karnesh , Rane Kaustubh S. , Errington Jeffrey R.
Published: February 2019

We introduce a molecular simulation method to compute the interfacial properties of model systems within the isothermal-isobaric ensemble. We use a free-energy-based approach in which Monte Carlo simulations are employed to obtain an interface potential associated with the growth of a fluid film from a solid substrate. The general method is implemented within “spreading” and “drying” frameworks. The interface potentials that emerge from these calculations provide direct access to spreading and drying coefficients. These macroscopic properties are then used to compute the liquid-vapor surface tension and the contact angle of a liquid droplet in contact with the substrate. The isothermal-isobaric ensemble provides a means to change the thickness of the fluid film adjacent to the substrate by modifying the volume of the simulation box. Molecular insertions and removals are not necessary. We introduce a framework for performing local volume change moves wherein one attempts to modify the density of a narrow region of the simulation box. We show that such moves improve the sampling efficiency of inhomogeneous systems. The approach is applied to a model system consisting of a monatomic Lennard-Jones fluid in the vicinity of a structureless substrate. Results are provided for direct spreading and drying interface potential calculations at several temperatures and substrate strengths. Expanded ensemble techniques are used to evaluate interfacial properties over a wide range of temperatures and substrate strengths. The results obtained using the isothermal-isobaric approach are compared with those previously obtained via a grand canonical approach.
Making sense of paying for performance in health care: short-term targets versus patient-relevant outcomes
Authors: Jan Stephen
Published: February 2019

Although there has been growing interest in pay-for-performance programs in health, the evidence of their success is weak. Reasons that have been posited for this are that they are misdirected (i.e. individual providers are not directly linked to incentives targeted at a practice level) or that they are too weak, either because of cost considerations or that they have been dominated by strong social or professional norms. In practice, a problem of pay-for-performance programs is that they are based on a transactional view of health care focused on short-term targets (such as vaccination rates, blood pressure control and screening rates). In designing pay-for-performance programs, health care needs to be seen as relational, which means rewarding on the basis of longer-term goals that may be more meaningful to patients, such as control of overall cardiovascular risk, quality of life, continuity of care and prevention of unplanned hospitalisations.
Age estimation of striped marlin (Kajikia audax) in the eastern North Pacific using otolith microincrements and fin spine sections
Authors: Shimose Tamaki , Yokawa Kotaro
Published: February 2019

The age of striped marlin (Kajikia audax) in days and years (daily and yearly ages) were estimated by counts of otolith microincrements (n=25) and dorsal fin spine annuli (n=175) using specimens caught in the tropical eastern North Pacific between September and November 2004. Daily ages of small striped marlin (87.0–145.5cm lower jaw–fork length) were estimated to range from 81 to 239 days, which indicates that the species in the area grow, on average, to over 100cm within 4 months. Back-calculated hatch dates were estimated to be from March to July; this period is earlier than the known spawning season in a slightly more northern area. Approximately 20% of these year-0 striped marlin had one or more growth bands in the sectioned spine. They were thought to be false annual growth bands and excluded from yearly age estimation. The estimated yearly age of 175 individuals (87.0–228.4cm) ranged from 0 to 5 and was dominated by ages-0 to 3 (>90%). Age composition was different among three subregions in the eastern North Pacific.
A Qualitative Analysis of Interprofessional Students’ Perceptions toward Patients with Opioid use Disorder after a Patient Panel Experience
Authors: Dumenco Luba , Monteiro Kristina , Collins Sally , Stewart Cynthia , Berkowitz Laureen , Flanigan Timothy , Rich Josiah , George Paul
Published: February 2019

Background: Students from health professional schools participated in a half-day interprofessional education workshop centered on substance use disorder training. One component was a patient panel featuring individuals with a history of opioid use disorder who described the impact of addiction on their lives and their road to recovery using varied treatment options. We hypothesized that interacting with individuals with opioid use disorder early in training would elicit more humanistic perspectives and decrease bias and stigma in future health care professionals. Methods: After participating in the panel experience, health professional students ( N = 580) from medicine, nursing, pharmacy, physical therapy, and social work were asked to complete short, 5-minute, rapid reflections. Prompts asked students whether the panel changed their perception of individuals with substance use disorder, to reflect on their attitudinal changes or lack thereof, and how working in interprofessional teams could impact the management and treatment of these patients. Conventional content analysis was performed. Results: Eighty-nine percent of students who attended the session completed the rapid reflections ( n = 514). Overall, approximately 70% ( n = 369) of students indicated that their perceptions of individuals with substance use disorder had changed as a result of the patient panel, with students from pharmacy more likely to indicate a change in attitudes. Themes across all professions included a change toward a more humanistic perspective, value of hearing real patient stories, and learning about treatment and recovery options. Student responses described how interprofessional health care teams can provide more holistic care with a broader range of therapeutic options that may improve long-term outcomes. Conclusions: A patient panel experience is influential on interprofessional students’ attitudes toward patients who suffer from opioid use disorder. Students identified an interprofessional approach as being a valuable component of management and treatment of these patients.
Predictors of Mental Health and Substance use Disorder Treatment use over 3 Years among Rural Adults using Stimulants
Authors: Cucciare Michael A. , Ounpraseuth Songthip T. , Curran Geoffrey M. , Booth Brenda M.
Published: February 2019

Background

Persons using substances, living in rural communities, tend to underutilize mental health (MH) and substance use disorder (SUD) treatment compared with their urban peers. However, no studies have examined longitudinal predictors of MH and SUD treatment use among rural persons using stimulants.

Methods

Data were collected through interviews conducted between 2002 and 2008 from a natural history study of 710 adults using stimulants and living in rural counties of Arkansas, Kentucky, and Ohio. Each study site recruited participants using respondent-driven sampling (RDS). Participants were adults, not in drug treatment, and reporting past-30-day use of methamphetamine, crack cocaine, or powder cocaine. Study participants completed face-to-face baseline assessments and follow-up interviews using computer-assisted personal interviews. Follow-up interviews were conducted at 6-month intervals for 3 years.

Results

Our results show that being male, nonwhite, and having a prior lifetime history of MH or SUD treatment use were associated with lower odds of using MH and SUD treatment over time; having medical insurance and living in a state with potentially greater availability of MH and SUD treatment were associated with higher odds of using MH and SUD treatment over the 3-year period. Further, reporting greater legal problems and alcohol severity were associated with greater odds of using MH and SUD care, whereas greater employment problems was associated with higher odds of SUD but not MH treatment use.

Conclusions

Findings from this study could be used to inform clinical and public health strategies for improving linkage to MH and SUD care in this population. Our findings also highlight the importance of having medical insurance as a potential facilitator to utilizing SUD care in this population and support the need for health care policies that increase the ability of rural adults who use stimulants to pay for such services.
Goal Commitment Predicts Cannabis use for Adolescents in Treatment
Authors: Kaminer Yifrah , Ohannessian Christine M. , Burke Rebecca H.
Published: February 2019

Background

Commitment to change is an innovative potential mediator and mechanism of behavior change (MOBC) that has not been examined in adolescents with cannabis use. The Adolescent Substance Abuse Goal Commitment (ASAGC) questionnaire is a reliable and valid 2-scale measure developed to assess the adolescent's commitment to either abstinence or harm reduction model for adolescents, which in addition to decrease in negative consequences includes consumption reduction as a stated treatment goal. The objective of this paper is to examine the ASAGC's ability to predict adolescent substance use treatment outcome.

Methods

During Sessions 3 and 9 of a 10-week treatment program, therapists completed the ASAGC for 170 adolescents 13–18 years of age with alcohol use disorders, the majority of whom (82%) were diagnosed with co-occurring cannabis use disorder (CUD).

Results

Logistic regression analyses assessing goal commitment regarding cannabis use at Session 3 indicated that commitment to both abstinence and harm reduction predicted cannabis use at Session 3. However, only commitment to abstinence predicted later cannabis use (assessed at Session 9 and during aftercare). When goal commitment at Session 9 was examined, only commitment to abstinence predicted cannabis use, concurrently and longitudinally. These results indicated that adolescents who had higher scores for commitment to abstinence were less likely to be positive for cannabis use. In contrast, harm reduction was not a significant predictor of cannabis use.

Conclusions

Findings demonstrate that goal commitment consistently predicts cannabis use treatment outcome. Commitment to abstinence specifically is a salient predictor for concurrent and future cannabis use. Further prospective study is necessary to determine whether harm reduction may be an attainable goal for some youth given normative delayed neurodevelopmental processes of inhibitive behaviors.
CRACR2a is a calcium-activated dynein adaptor protein that regulates endocytic traffic
Authors: Wang Yuxiao , Huynh Walter , Skokan Taylor D. , Lu Wen , Weiss Arthur , Vale Ronald D.
Published: February 2019

Cytoplasmic dynein is a minus end–directed microtubule motor that transports intracellular cargoes. Transport is initiated by coiled-coil adaptors that (a) join dynein and its cofactor dynactin into a motile complex and (b) interact with a cargo-bound receptor, which is frequently a Rab GTPase on an organelle. Here, we report two novel dynein adaptors, CRACR2a and Rab45, that have a coiled-coil adaptor domain, a pair of EF-hands, and a Rab GTPase fused into a single polypeptide. CRACR2a-mediated, but not Rab45-mediated, dynein motility is activated by calcium in vitro. In Jurkat T cells, elevation of intracellular calcium activates CRACR2a-mediated dynein transport. We further found that T cell receptor activation induces the formation of CRACR2a puncta at the plasma membrane, which initially associate with the actin cortex and subsequently detach and travel along microtubules, suggestive of an endocytic process. These results provide the first examples of Rab GTPases that directly act as dynein adaptors and implicate CRACR2a–dynein in calcium-regulated endocytic trafficking.