bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonic fatigue testing under multiaxial loading conditions on a railway wheel
Authors: da Costa Pedro R. , Soares Henrique , Reis Luís , Freitas Manuel
Published: December 2019

Ultrasonic fatigue testing is a relative recent fatigue methodology that uses resonant principles for the induction of stress cycles in a specific designed material specimen. This experimental method can apply very high cycle frequency, the most common frequency being 20 kHz, and was created with the main purpose of studying material fatigue life in the Very High Cycle Fatigue regime between 107 and 109 cycles with a higher performance of time and energy wise in comparison to conventional servo-hydraulic machines. In this study an improvement of an already built multiaxial ultrasonic fatigue machine in the Instituto Superior Técnico laboratories was carried out to specific designed specimens and afterwards a fatigue study was made for a material of a worn-out railway wheel. The particular design of the specimen was achieved by numerical and experimental analysis based on previous experiments and components. Thermographic imaging and the application of rosette strain gauges to the main throat of the specimens were conducted in order to validate the improved specimen design and to understand the real induced stresses on the specimen. Afterwards fatigue tests were conducted for several specimens for a wide range of stresses with a stress ratio R=-1 and an axial vs shear stress ratio of around 0.58. Results were analysed and fracture analysis was also carried out.
Level of Readiness Index for Conceptual Design Refinement
Authors: Iino Kenji , Nakao Masayuki
Published: December 2019

The authors have been teaching conceptual design courses to graduate schools and adult groups. Despite the instructors’ encouragement to refine a design to a level that clarifies the elemental functional requirement for each part element, the students often lump elemental functional requirements into higher level functions. The resulting Design Record Graph shows a functional requirement with multiple arcs extending to the corresponding nodes in the design parameter space. When such a design maps to a Design Matrix in Axiomatic Design, the matrix turns into a rectangular one with non-diagonal elements. Instead of just speaking to the students that they will face difficulty when it comes to producing prototypes, the authors developed a metric that quantifies the level of detail of a design so the students, often driven to gain higher numerical scores, will naturally spend efforts to refine their designs to levels that are ready for building prototypes. We call this metric Level of Readiness Index, i.e., LOR Index.
Green Product Module Partition Method Based on Improved Multi-objective Artificial Bee Colony Algorithm
Authors: Wei Wei , Zhan Yang
Published: December 2019

Modular design is an important design method in the mass customization for manufacturing industry. The purpose of this paper is to meet diverse market demands while reducing the impact of products on the ecological environment. Firstly, aiming at the product life cycle process, this paper summarizes the problems encountered in each stage of the product, and introduces five green product module partition principles. Then, through the component correlation matrix, the resource greenness objective function based on the whole life cycle and the polymerization degree objective function based on the component correlation matrix are established respectively by the axiomatic design theory which makes the product mapping from functional domain to structural domain. Next, an improved artificial bee colony algorithm is proposed. Based on the artificial bee colony algorithm, the algorithm applies congestion strategy and fast nondominated sorting strategy to solve the module partition problem of product platform with multi-objective optimization, and a uniformly distributed pare to solution set is generated. Through above steps, the optimization results of module partition are obtained. Finally, an application example of aircraft tail horizontal stabilizer parts is given, and the advantages of the algorithm are proved by comparing with other algorithms.
Effect of minimum quantity lubrication strategies on tribological study of simulated machining operation
Authors: Werda Sana , Duchosal Arnaud , Le Quilliec Guénhaël , Morandeau Antoine , Leroy René
Published: December 2019

The main aim of this paper was to reproduce the frictional behaviour that occurred in milling with a pin-on-cylinder system. Three different tribological tests were conducted reproducing friction phenomenon that happened in three machining conditions: (i) dry rubbing, representing the dry machining condition, (ii) MQL applied to front face rubbing which was similar to milling with MQL applied on the insert rake face and (iii) MQL applied to rear end rubbing which was similar to milling with MQL applied on flank face. Tribological tests were carried out with coated tungsten carbide pins rubbing on X100CrMoV5 steel cylinder. Apparent coefficient of friction, adhesion area and heat flux transmitted to the pin were analysed. It has been shown that MQL rear end rubbing provided a lower adhesion area and lower apparent coefficient of friction than with MQL front face rubbing. Furthermore, MQL rear end rubbing resulted in a greater cooling ability. These findings helped to explain why better results were obtained with MQL flank face lubrication in milling compared to MQL rake face lubrication.
From Hertzian contact to spur gears: analyses of stresses and rolling contact fatigue
Authors: Vouaillat Guillaume , Noyel Jean-Philippe , Ville Fabrice , Kleber Xavier , Rathery Sylvain
Published: December 2019

The study of rolling contact fatigue in spur gears requires a good comprehension of all the phenomena occurring at the material scale. On a numerical point of view, a realistic representation of the material and of the load repartition function of the local micro-geometries is needed. However the resulting models are often complex and time-consuming. So, this work aims at developing a model meeting these specificities. Thus, different sections of the spur gear material granular geometry are simulated first. Secondly, the contact pressure fields are computed accurately relatively to the simulated surface microgeometry. Then, the influence of several parameters on their rolling contact fatigue life is highlighted. Among friction, sliding coefficient, load variation and roughness, these individual or combined parameters are taken into account in the model, tested and their impact stressed out. Finally, a fatigue criteria based on rolling contact fatigue micro-cracks nucleation at grain boundaries is proposed in order to compare simulations and influencing parameters to the reference.
Plattenepithelkarzinome der Kopf-Hals-Region (SCCHN)
Authors: Pogorzelski Michael , Grünwald Viktor
Published: December 2019

Was ist neu?

Prävention Die Aufklärung der Bevölkerung über den gesicherten Zusammenhang von Alkohol- und Tabakkonsum mit der Entstehung von Kopf-Hals-Tumoren ist weiterhin dringend erforderlich. Zur Prävention der HPV-assoziierten Tumoren stehen Vakzine zur Verfügung. Gemäß der Empfehlung der STIKO sollten alle Jungen und Mädchen im Alter zwischen 9 und 14 Jahren geimpft werden.

Ausbreitungs- und Rezidivdiagnostik Die FDG-PET/CT ermöglicht die Verringerung operativer Eingriffe. Bei N2/N3-Status nach definitiver Radiochemotherapie (RCT) sollte eine Neck Dissection nur bei positivem/unklarem PET-Befund durchgeführt werden. Bei Verdacht auf ein Rezidiv eines Larynxkarzinoms kann die FDG-PET/CT helfen, eine Larynxbiopsie zu vermeiden. Bei zervikalem CUP-Syndrom (d.h. bei unklarem Primärtumor) ist sie zudem zur Primarius- und Ausbreitungsdiagnostik indiziert.

Stadieneinteilung und Prognostizierung HPV-induzierte Oropharynxkarzinome weisen eine bessere Prognose auf. Die 8. Version der TNM-Klassifikation umfasst daher eine klinische und eine pathologische Klassifikation für diese Tumorentität. Die Therapieplanung erfolgt auch weiterhin nach den etablierten Kriterien der 7. Version.

Lokal fortgeschrittene Stadien Zur Reduktion therapieassoziierter Toxizität wird derzeit eine Therapiedeeskalation bei HPV-assoziierten Oropharynxkarzinomen (HPV-OPC) evaluiert. Bisherige Studien waren jedoch negativ, sodass derzeit keine Anpassung der Therapie anhand des HPV-Status im klinischen Alltag erfolgt.

Palliative Systemtherapie Die Immuncheckpointinhibitoren Nivolumab und Pembrolizumab stellen den neuen Standard nach Versagen einer platinhaltigen Therapie dar. In der Keynote-048-Studie demonstrierte Pembrolizumab als Monotherapie für Patienten mit Expression von PD-L1 (CPS ≥ 1) sowie in der Kombination mit Platin + 5-FU in der unselektierten Patientenpopulation seine Überlegenheit gegenüber dem bisherigen Erstlinienstandard PFC.
Das Schmidt-Syndrom
Authors: Stahn Bonnie , Scheit Lorenz
Published: December 2019

Anamnese und klinischer Befund Wir berichten über einen 22-jährigen Patienten, der sich mit Abgeschlagenheit, Gewichtsverlust und Verfärbung der Haut vorstellte. Eine Hashimoto-Thyreoiditis war bekannt. Die Hormonsubstitution mit L-Thyroxin war bereits erhöht worden. Allerdings persistierten die Beschwerden.

Diagnostik Die körperliche Untersuchung zeigte eine gelblich-graue Verfärbung der Haut. Zudem fielen laborchemisch eine Hyponatriämie und eine Hyperkaliämie auf. Kortisolspiegel, Antikörperbestimmungen sowie ein ACTH-Stimulationstest bestätigten die Diagnose eines Morbus Addison. In Zusammenschau mit der bekannten Hashimoto-Thyreoiditis ergab sich das Bild eines Schmidt-Syndroms.

Therapie und Verlauf Es erfolgte die Substitution mit 20 mg Hydro- und 0,1 mg Fludrokortison täglich, worunter es innerhalb einer Woche zur Beschwerdebesserung und Normalisierung der Laborparameter kam.

Folgerung Die Erkrankungen und Symptome, die im Rahmen einer autoimmunen Polyendokrinopathie vorliegen können, erschweren häufig eine schnelle Diagnose. Daher sollte bei Patienten mit bereits bekannter Autoimmunerkrankung an die Möglichkeit einer autoimmunen Polyendokrinopathie gedacht werden.
Tumorprävention
Authors: Schmale Ine
Published: December 2019

Schlank, fit und vor allem gesund – wer möchte das nicht sein? Dabei sollen „Superfoods“ helfen. So bezeichnet die Werbung Lebensmittel, die aufgrund ihrer Nährstoffzusammensetzung besonders förderlich für Gesundheit und Wohlbefinden sein sollen. Häufig handelt es sich um exotische Pflanzen, wie Chiasamen, Açai- oder Gojibeeren, oft in getrockneter Form, als Püree oder Extrakt. Sie sollen nicht nur leistungsfähiger machen, den Alterungsprozess aufhalten und das Herz stärken – auch vor Krebs sollen diese Alleskönner schützen. Was ist so super am Superfood? Der Krebsinformationsdienst des Deutschen Krebsforschungszentrums gibt Antwort.
Bariatric endoscopy procedure type or follow-up: What predicted success at 1 year in 962 obese patients?
Authors: Lopez-Nava Gontrand , Asokkumar Ravishankar , Rull Angel , Corbelle Fernandez , Beltran Lucia , Bautista Inmaculada
Published: December 2019

Background and study aims It is uncertain if the difference in weight loss outcomes between different endoscopic bariatric therapies (EBTs) is technique-related or multidisciplinary team (MDT) follow-up-related. We hypothesized that at 1 year, the weight loss is determined more by adherence to MDT follow-up than by procedure type. We aimed to compare 1 year weight loss outcomes of four different EBTs at a single center with a standardized MDT follow-up.

Patients and methods We prospectively collected and retrospectively analyzed outcomes in 962 patients (female-691, 71.2 %; mean age, 44.8 ± 10.6 years, mean BMI, 37.8 ± 5.9 Kg/m2) treated with Intragastric balloons (IGBs) or endoscopic gastroplasty (EG) at HM Sanchinarro University Hospital between March 2012 to January 2017. The procedures were performed by the same endoscopist and followed up by the same MDT. We compared the percentage total body weight loss (%TWBL) at 1 year. We performed linear and logistic regression to identify predictive factors for weight loss and follow-up adherence at 1 year.

Results Four hundred and eighty-one IGBs (Orbera-80.9 %; ReShape Duo-19.1 %), and 481 EG (Apollo ESG-51.3 %; Primary obesity surgery endoluminal-POSE-48.6 %) were performed. Only 480 patients (IGB- 45 %; EG- 55 %) completed 1 year follow-up. Among them, Apollo ESG achieved significantly higher TBWL (19.5 ± 13 %, P = 0.035), %TBWL (17.4 ± 10.2 %, P = 0.025), and ≥ 20 % TBWL (36.7 %, P = 0.032). However, in linear regression after adjusting for variables, only higher initial BMI (B = 0.31, P < 0.001) and higher percentage follow-up attendance (B = 0.24, P < 0.001) significantly predicted %TBWL at 1 year in the completion group but not the procedure type (B = 0.02, P = 0.72). In logistic regression, we observed female sex (P = 0.01), high initial BMI (P < 0.001), endoscopic gastroplasty (P = 0.04), and high 1-month %TBWL (P < 0.001) significantly predicted follow-up completion at 1 year.

Conclusions Weight loss at 1 year is dependent on MDT follow-up rather than procedure type. Endoscopic gastroplasty promoted follow-up adherence more than IGBs.
TKI-Resistenzen beim EGFR-positiven NSCLC
Authors: Krome Susanne
Published: December 2019

EGFR-Tyrosinkinase-Inhibitoren (EGFR-TKI) haben zu einem Paradigmenwechsel in der Behandlungsstrategie für nicht-kleinzellige Bronchialkarzinome (NSCLC) geführt und gehören inzwischen zum Standard. Dabei ist es auch wichtig, primäre und erworbene Resistenzen zu überwinden. Eine aktuelle Studie mit 116 Patienten ergab unterschiedliche Resistenz-Mechanismen für TKI der 1./2. und der 3. Generation. Die Liquid Biopsy ist nach Ansicht der Autoren eine Option für ein nicht-invasives Monitoring der molekularen Veränderungen unter der EGFR-Therapie. Ein Review beschäftigte sich mit den Resistenzmechanismen und der Liquid Biopsy als Instrument für die Therapieplanung und -monitoring.
Nutzenvorhersage mit der PD-L1-Expression bleibt schwierig
Authors: Krome Susanne
Published: December 2019

Der immunhistochemische Nachweis der PD-L1-Expression in Primärtumor und Metastasen ist der einzige Biomarker, der die Effektivität einer Immuntherapie des nicht-kleinzelligen Bronchialkarzinoms vorhersagt. Unterschiedliche Assays, Cutoffs sowie der inter- und intratumoral heterogene Nachweis erfordern methodische Verbesserungen.
Kolorektales Karzinom
Authors: Krome Susanne
Published: December 2019

Nach der Resektion kolorektaler Karzinome im Stadium I–III erhalten ausgewählte Patienten eine adjuvante Chemotherapie. 2 Arbeitsgruppen zeigten nun, dass die zirkulierende, zellfreie Tumor-DNA (ctDNA) anzeigt, welche Patienten profitieren. Darüber hinaus bestand ein enger Zusammenhang zwischen der ctDNA, der Rezidivwahrscheinlichkeit und dem Überleben.
Kleinzelliges Lungenkarzinom
Authors: Kretzschmar Alexander
Published: December 2019

In der Vergangenheit sind viele Behandlungsansätze beim kleinzelligen Lungenkarzinom (SCLC) gescheitert. Die Entwicklung der Checkpoint-Inhibitoren zeigt sich jetzt auch bei dieser Tumorentität als effektive Option. Auf dem WCLC zeigten neue Auswertungen der CASPIAN-Studie eine signifikante Verlängerung des Gesamtüberlebens (OS) um 27 % unter der Kombination des Checkpointinhibitors Durvalumab plus einer Etoposid- und platinbasierten Chemotherapie im Vergleich zur Chemotherapie allein.
Untersuchungen zum Verlauf der Lebensqualität vor und bis 2 Jahre nach anatomischer Resektion bei Patienten mit Lungenkarzinom – ein Vergleich zwischen anterolateraler Thorakotomie und videoassistierter Thorakoskopie
Authors: Hoeffkes Daniel , Welcker Katrin , Hendrix Holger , Kamlak Vladimir , Prisadov Georgi , Noack Frank , Meyer Andreas
Published: December 2019

Hintergrund Es existieren zahlreiche Publikationen, aus denen hervorgeht, dass in der operativen Therapie des nicht kleinzelligen Lungenkarzinoms durch einen minimalinvasiven Zugang vergleichbare onkologische Resektionsergebnisse erzielt werden wie nach einer Thorakotomie. Herausgearbeitet wurde außerdem, dass ein minimalinvasiver Zugang mit geringeren postoperativen Komplikationen und einem kürzeren Krankenhausaufenthalt einhergeht. Ungeklärt ist jedoch bisher, ob die Wahl des operativen Zugangs mit einem Unterschied in der gesundheitsbezogenen Lebensqualität assoziiert ist.

Material und Methoden Aus dem Patientenkollektiv unseres von der Deutschen Krebsgesellschaft (DKG) zertifizierten Lungenkrebszentrums wurden 327 Patienten befragt, die zwischen 2010 und 2017 operiert wurden. Ausgehend von insgesamt 456 verwertbaren Short-Form-12-Fragebögen wurden standardisierte Kenngrößen für das subjektiv empfundene physische und psychische Wohlbefinden gebildet. Diese wurden zunächst zu Kenngrößen der deutschen Normbevölkerung in Relation gesetzt, bevor eine Gegenüberstellung der Lebensqualität von Patienten nach anterolateraler Thorakotomie mit denen von Patienten nach einer videoassistierten Thorakoskopie erfolgte.

Ergebnisse Mit einigen Limitationen konnte herausgearbeitet werden, dass die körperliche Dimension der postoperativen Lebensqualität von Patienten mit einem nicht kleinzelligen Lungenkarzinom langfristig eingeschränkt bleibt, während die psychische Dimension nicht relevant eingeschränkt ist. Hierbei ist die Wahl eines minimalinvasiven Zugangs postoperativ nicht mit einer höheren gesundheitsbezogenen Lebensqualität assoziiert.

Schlussfolgerungen Unter dem Aspekt der gesundheitsbezogenen Lebensqualität scheinen beide Zugangswege gleichwertig. Der Trend in der Entwicklung sowohl der körperlichen als auch der psychischen Dimension der Lebensqualität nach videoassistierter Thorakoskopie deutet jedoch einen längerfristigen Vorteil des minimalinvasiven Zugangs an.
Efficacy and Safety of Nonvitamin K Oral Anticoagulants in Patients with Atrial Fibrillation and Cancer: A Study-Level Meta-Analysis
Authors: Cavallari Ilaria , Verolino Giuseppe , Romano Silvio , Patti Giuseppe
Published: December 2019

Objectives In this study-level meta-analysis, we evaluated the clinical outcome with nonvitamin K antagonist oral anticoagulants (NOACs) versus vitamin K antagonists (VKAs) in atrial fibrillation (AF) patients with cancer.

Background Anticoagulation in AF patients with cancer is challenging given the coexistence of elevated thrombotic and bleeding risk. The efficacy and safety of NOACs in this setting remain unclear.

Methods We included three randomized trials in our primary analysis (N = 2,661 patients) and three observational studies in our secondary, confirmatory analysis (N = 21,112 patients). Outcome measures were: the composite of any stroke or systemic embolism, ischemic stroke, venous thromboembolism, major bleeding, intracranial bleeding; and all-cause death. Mean follow-up duration was 2.2 years.

Results In the primary analysis, the use of NOACs was associated with similar incidence of stroke/systemic embolism (odds ratio [OR] 0.70, 95% confidence interval 0.45–1.09; p = 0.11), ischemic stroke (OR 0.71, 0.31–1.64; p = 0.42), venous thromboembolism (OR 0.91, 0.33–2.53; p = 0.86), all-cause death (OR 1.02, 0.72–1.42; p = 0.93), and major bleeding (OR 0.81, 0.61–1.06; p = 0.13) compared with VKAs. The occurrence of intracranial bleeding was significantly lower in the NOACs versus VKAs group (OR 0.11, 0.02–0.63; p = 0.01). These results were overall confirmed in the secondary analysis, where there was additionally a significant reduction of stroke/systemic embolism, ischemic stroke, and venous thromboembolism with NOACs.

Conclusion In AF patients with malignancy, NOACs appear at least as effective as VKAs in preventing thrombotic events and reduce intracranial bleeding. NOACs may represent a valid and more practical alternative to VKAs in this setting of high-risk patients.
Segmental Arterial Mediolysis with Supra-Aortic Vascular Involvement: Report of Two Cases
Authors: Jain Vikash
Published: December 2019

Segmental arterial mediolysis (SAM) is a rare noninflammatory vasculopathy predominantly involving the visceral arteries of the abdomen. The most common presentation described is massive intra-abdominal hemorrhage secondary to aneurysm rupture. In this report, we describe two cases with characteristic findings of aneurysm, dissection, and beading involving the visceral arteries and the supra-aortic vessels. SAM involving the supra-aortic vessels is extremely rare.
Patientenlogistik und Touchpoint-Analyse: Patient als Invisible Hand
Authors: Kriegel Johannes
Published: December 2019

Das Krankenhauswesen steht vor der enormen Herausforderung, die steigende Leistungsnachfrage sowie das arbeitsteilige Leistungsspektrum und die resultierende Behandlungsqualität sicherzustellen. Die verstärkte Betrachtung der Patientenströme sowie die patientenbezogene Leistungserbringung erschließen dabei mögliche Ressourceneffizienzen.
The effect of a worldwide tax system on tax management of foreign subsidiaries
Authors: Kohlhase Saskia , Pierk Jochen
Published: December 2019

Under a worldwide tax system, firms pay taxes on their domestic income and repatriated foreign income, whereas under a territorial tax system repatriated foreign income is exempt from taxation. We examine whether worldwide tax systems reduce the incentives of multinational corporations to engage in tax management in their foreign subsidiaries. Using two quasi-natural experiments, we show that multinationals lower the effective tax rates in their foreign subsidiaries after countries switch from a worldwide to a territorial tax system. Thus, multinationals subject to a worldwide tax system face competitive disadvantages compared to competitors from countries with a territorial tax system.
Classification of the Reynolds stress anisotropy tensor in very large thermally stratified wind farms using colormap image segmentation
Authors: Ali Naseem , Hamilton Nicholas , Calaf Marc , Cal Raúl Bayoán
Published: December 2019

A combinatorial technique merging image segmentation via K-means clustering and colormap of the barycentric triangle is used to investigate the Reynolds stress anisotropy tensor. The clustering aids in extracting the identical features from the spatial distribution of the anisotropy colormap images by minimizing the sum of squared error between the cluster center and all data points. The dataset used to investigate the applicability of the clustering technique consists of the flow in a large wind farm for different thermal stratification representatives of a characteristic diurnal cycle. Based on the attribute values defining the colormap of the Reynolds anisotropy stress tensor, the images are converted into color space and then the K-means algorithm assesses the similarities and dissimilarities via a distance metric. In unsupervised learning problems, the K-means algorithm runs independently for different numbers of clusters. The elbow criterion is used to determine the best trade-off between the cluster number and the total variance to select the optimal number of clusters. The clustering technique improves pattern visualization and allows us to identify characteristic regions of the flow based on the structure of the Reynolds stress anisotropy. The dominant patterns reveal that there are major perturbations that control the operation of the wind farm during the diurnal cycle, including the formation and growth of the convective boundary layer and the strong stratification among the flow layers during the stably-stratified period. These parameters attempt to redistribute energy into the velocity deficit region and contribute to the energy balance in the flow domain through the distributions of the momentum flux. As a result of the weak mixing and negligible buoyancy effect, the neutral wind farm displays gradual changes from a prolate turbulence state near the rotor to an oblate turbulence state at the top of the domain.
Cycle-SfM: Joint self-supervised learning of depth and camera motion from monocular image sequences
Authors: Sun Qiyu , Tang Yang , Zhao Chaoqiang
Published: December 2019

Understanding 3D scene geometry is a fundamental research topic in computer vision, including various subproblems, such as depth prediction, visual odometry, optical flow, etc. With the advent of artificial intelligence methods like deep learning, many approaches have emerged to deal with such problems in an end-to-end manner. These pipelines take the 3D understanding task as a nonlinear optimization problem, with the purpose of minimizing the cost function of the whole framework. Here, we present a self-supervised framework for jointly learning the monocular depth and camera’s ego-motion from unlabeled, unstructured, and monocular video sequences. We propose a forward-backward consistency constraint on view reconstruction to capture temporal relations across adjacent frames, whose purpose is to explore and make full use of the bidirectional projection information. A simple and practicable improvement on the design of cost function is proposed to enhance the estimated accuracy. Due to the fact that our improvement is a lightweight and general module, it can be integrated into any self-supervised architectures seamlessly, and more accurate results can be obtained. The evaluation on the KITTI dataset demonstrates that our approach is highly efficient and performs better than the existing works in pose estimation, while the results in depth estimation perform comparably with the existing ones.
Parameter extension simulation of turbulent flows
Authors: Jin Yan
Published: December 2019

The use of parameter extension simulation (PES) as a mathematical method for simulating turbulent flows is proposed in this study. It is defined as the calculation of a turbulent flow with the help of a reference solution. A typical PES calculation includes three steps, as follows: setting up an asymptotic relationship between the exact solution of the Navier–Stokes equations and the reference solution for the initial parameter values, calculating the reference solution and the necessary asymptotic coefficients, and extending the reference solution to the parameter values to produce the exact solution. The method of controlled eddy simulation (CES) has been developed to calculate the reference solution and the asymptotic coefficients. The CES method is a special case of large eddy simulation (LES), in which a weighting coefficient and an artificial force distribution are used to damp part of the turbulent motions. The distribution of artificial force is modeled with the help of eddy viscosity. The reference-weighting coefficient can be determined empirically or in a convergence study. To demonstrate potential uses, the proposed PES method is used to simulate four types of turbulent flows. The flows are decaying homogeneous and isotropic turbulence, smooth-wall channel flows, rough-wall channel flows, and compressor-blade cascade flows. The numerical results show that the PES solution is more accurate than a Reynolds-average Navier–Stokes simulation solution. Unlike a traditional LES method, which uses the Smagorinsky, k-equation-transport, or WALE subgrid model, the PES requires a lower mesh resolution. These characteristics make it a potential method for simulating the engineering of turbulent flows with complex geometry and a high Reynolds number.
Input data reduction for microgrid sizing and energy cost modeling: Representative days and demand charges
Authors: Fahy Kelsey , Stadler Michael , Pecenak Zachary K. , Kleissl Jan
Published: December 2019

Computational time in optimization models scales with the number of time steps. To save time, solver time resolution can be reduced and input data can be down-sampled into representative periods such as one or a few representative days per month. However, such data reduction can come at the expense of solution accuracy. In this work, the impact of reduction of input data is systematically isolated considering an optimization which solves an energy system using representative days. A new data reduction method aggregates annual hourly demand data into representative days which preserve demand peaks in the original profiles. The proposed data reduction approach is tested on a real energy system and real annual hourly demand data where the system is optimized to minimize total annual costs. Compared to the full-resolution optimization of the energy system, the total annual energy cost error is found to be equal or less than 0.22% when peaks in customer demand are preserved. Errors are significantly larger for reduction methods that do not preserve peak demand. Solar photovoltaic data reduction effects are also analyzed. This paper demonstrates a need for data reduction methods which consider demand peaks explicitly.
Blow-up for trapped dipolar quantum gases with large energy
Authors: Gao Yanfang , Wang Zhiyong
Published: December 2019

We consider a Gross–Pitaevskii equation with harmonic potential arising in dipolar Bose–Einstein condensate. We extend the scope of blow-up solutions in the work of Carles, Markowich, and Sparber [Nonlinearity 21(11), 2569–2590 (2008)] to those with arbitrarily large energy in a partial unstable regime.
AAV-mediated gene therapy targeting TRPV4 mechanotransduction for inhibition
of pulmonary vascular leakage
Authors: Li Juan , Wen Amy M. , Potla Ratnakar , Benshirim Ezekiel , Seebarran Ariel , Benz Maximilian A. , Henry Olivier Y. F. , Matthews Benjamin D. , Prantil-Baun Rachelle , Gilpin Sarah E. , Levy Oren , Ingber Donald E.
Published: December 2019

Enhanced vascular permeability in the lungs can lead to pulmonary edema, impaired gas exchange, and ultimately respiratory failure. While oxygen delivery, mechanical ventilation, and pressure-reducing medications help alleviate these symptoms, they do not treat the underlying disease. Mechanical activation of transient receptor potential vanilloid 4 (TRPV4) ion channels contributes to the development of pulmonary vascular disease, and overexpression of the high homology (HH) domain of the TRPV4-associated transmembrane protein CD98 has been shown to inhibit this pathway. Here, we describe the development of an adeno-associated virus (AAV) vector encoding the CD98 HH domain in which the AAV serotypes and promoters have been optimized for efficient and specific delivery to pulmonary cells. AAV-mediated gene delivery of the CD98 HH domain inhibited TRPV4 mechanotransduction in a specific manner and protected against pulmonary vascular leakage in a human lung Alveolus-on-a-Chip model. As AAV has been used clinically to deliver other gene therapies, these data raise the possibility of using this type of targeted approach to develop mechanotherapeutics that target the TRPV4 pathway for treatment of pulmonary edema in the future.
Carbon pair defects in aluminum nitride
Authors: Gamov I. , Hartmann C. , Wollweber J. , Dittmar A. , Straubinger T. , Bickermann M. , Kogut I. , Fritze H. , Irmscher K.
Published: December 2019

AlN bulk single crystals grown by the physical vapor transport method may be beneficially applied as substrates for deep ultraviolet light emitting devices or as a basic material for piezoelectric resonators operating at high temperatures. Identification of point defects which deteriorate the optical, electrical, and electromechanical properties of AlN crystals for such applications is the subject of the present work. Using Raman spectroscopy, two local vibrational modes (LVMs) were discovered at wave numbers of 1189 cm−1 and 1148 cm−1. By analyzing an AlN crystal intentionally enriched with the carbon isotope 13C, it is unambiguously shown that the two LVMs originate from two different, but in each case carbon-related defects. Furthermore, it is evidenced that the defect underlying the LVM at 1189 cm−1 contains exactly two carbon atoms. The tricarbon defect-related LVM reported earlier in an infrared absorption study is found to be Raman active at 1772 cm−1. The Raman scattering intensity of all three LVMs strongly depends on the photon energy of the exciting light what is interpreted as a resonance Raman effect. This allows linking the identified defects with their contribution to the strong, carbon-related ultraviolet absorption around 4.7 eV and proves that these defects introduce optically and electrically active deep levels in the bandgap of AlN.
Diamond Lamb wave spin-mechanical resonators with optically coherent nitrogen vacancy centers
Authors: Lekavicius Ignas , Oo Thein , Wang Hailin
Published: December 2019

We report the design and fabrication of diamond Lamb wave spin-mechanical resonators embedded in a two-dimensional (2D) phononic crystal square lattice. The rectangular resonator features gigahertz in-plane compression modes protected by the phononic bandgap of the square lattice. A membrane-in-bulk approach is developed for the fabrication of the suspended 2D structure. This approach overcomes the limitations of fabrication approaches, which are either incompatible with the necessary high-temperature thermal annealing or unsuitable for 2D structures with the required feature size. Graded soft oxygen etching, with the etching rate decreased gradually to below 1 nm/min, is used to remove defective surface layers damaged by reactive ion etching. Combining the graded etching with other established surface treatment techniques reduces the optical linewidth of nitrogen vacancy centers in resonators with a thickness below 1 μm to as narrow as 330 MHz.
Enhancement of conductivity and transmittance of graphene oxide/PEDOT:PSS electrodes and the evaluation of charge transfer dynamics
Authors: das Neves Matheus Felipe Fagundes , Damasceno João Paulo Vita , Holakoei Soheila , Rocco Maria Luiza M. , Zarbin Aldo José Gorgatti , De Oliveira Camilla Karla Brites Queiroz Martins , Roman Lucimara Stolz
Published: December 2019

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS, is a polymeric composite that can substitute indium tin oxide (ITO), enabling ITO-free organic devices. However, PEDOT:PSS films have conductivities two orders of magnitude lower than ITO due to the presence of PSS, an insulator polymer added to provide water dispersion to PEDOT. To enhance the electrical performance of the films and overcome the insulator limitations, we prepared thin films of graphene oxide (GO) and PEDOT:PSS composites. The dried films were then treated with ethylene glycol (EG). An increment of two orders of magnitude in conductivity values was observed, as well as an increase in transmittance at the visible region. Also, GO:PEDOT:PSS thin films became more hydrophobic due to the partial removal of PSS. The mass ratio that is equal to 0.058 of GO/PEDOT provides higher electrical conductivity due to higher chain orientation of PEDOT as seen in the near edge X-ray absorption fine structure and resonant Auger spectroscopy measurements. The electrical transport follows the Mott Variable Range Hopping model for low temperature, showing that the conduction occurs in three dimensions. The solvent treatment increases the characteristic conductivity and decreases the activation hopping energy, with the characteristic temperature remaining almost unchanged. It indicates that the EG treatment promotes a decrease in charge transfer time and resistivity.
Non-diffracting light in nature: Anomalously reflected self-healing Bessel beams from jewel scarabs
Authors: Bouchal Petr , Kapitán Josef , Konečný Martin , Zbončák Marek , Bouchal Zdeněk
Published: December 2019

We report a study of spatial light modulation in the photonic structure of jewel scarabs, revealing the interplay of the polarization and phase control of light, which is not possible with the current optical technology. Phase measurements performed on jewel scarabs demonstrate that the polarization anomalous (helicity-preserving) reflection of light occurs together with alteration of the dynamic phase associated with the optical path length. This control of light differs from the operation of artificially prepared polarization-sensitive structures, shaping light through the geometric phase altered by the polarization transformation. Challenging three-dimensional imaging of the cuticle, requiring high-resolution quantitative mapping of steep phase changes, has been achieved owing to the optical performance of recently developed geometric-phase microscopy. We find that the cuticle of jewel scarabs is formed of micrometer-sized axicon cells, generating thousands of Bessel beams with subwavelength spot size. The nondiffracting features and the self-healing ability of the Bessel beams originating from the beetle Chrysina gloriosa are demonstrated experimentally. Considering Bragg reflection and shaping of RGB components of white light Bessel beams, we explain the spatial structuring of colors in microscopic images of jewel scarabs and reveal the conversion of colors when changing the distance from the cuticle. The functionality and performance of the cuticle axicon cells are discussed in comparison with high-aperture dielectric meta-axicons, and potential applications in colorimetric refractive index sensing are outlined.
Ab initio investigation of the atomistic descriptors in the activation of small molecules on 3d transition-metal 13-atom clusters: The example of H2, CO, H2O, and CO2
Authors: Ocampo-Restrepo Vivianne K. , Zibordi-Besse Larissa , Da Silva Juarez L. F.
Published: December 2019

The identification of the most important descriptors that drive the activation CO2 on transition-metal (TM) catalysts is a crucial step toward the conversion of CO2 into value-added chemicals; however, our atomistic understanding is far from satisfactory. Thus, aiming at the potential use of TM clusters in the conversion of CO2, we report density functional theory calculations of CO2, CO, H2O, and H2 adsorption on TM13 clusters (TM = Fe, Co, Ni, and Cu). Among the descriptors to evaluate the activation of the studied molecules, we found that the bond lengths increase, angles decrease, and their energetic variations upon the adsorption are the most important ones. From the structural response in anionic gas-phase molecules, the charge transfer toward CO2 and CO is pointed as relevant in their activation, and our results and analyses suggest that the adsorption on 3d TM13 clusters promote this charge donation process, decreasing in the order Fe13 > Co13 > Ni13 > Cu13. For CO2 and CO on Cu13, the activation was observed for highest energy configurations, indicating that is necessarily an additional driving force to occur the molecular activation on this material. Also, energetic parameters, adsorption energy, and interaction energy indicated that the strength of the adsorption is not necessarily proportional to the activation; it is difficult to point out these parameters as descriptors. Our results also provide interesting insights about steps of the CO2 reduction mechanism within the context of the modified Fischer–Tropsch synthesis.
Extraction of interface trap density by analyzing organohalide perovskite and metal contacts using device simulation
Authors: Shim Hayeon , Kwon Yongwoo
Published: December 2019

We estimated the interface trap density by examining methylamine-lead-iodide (MALI, CH3NH3PbI3) and metal contacts. We analyzed experimental current-voltage curves from two MALI-based resistive memory devices, which are Au/MALI/indium-tin-oxide and Ag/MALI/Pt, using a device simulator. We obtained effective work functions (EWFs) for MALI/metal contacts by considering Fermi level pinning attributed to the interface states comprising metal-induced gap states (MIGSs) and interface traps. Through our theoretical consideration, we concluded that the interface trap density is about 1015 eV−1 cm−2 at MALI/metal contacts because the low MIGS density of about 1013 eV−1 cm−2 obtained from a theoretical equation makes little contribution to the interface state density of 1015 eV−1 cm−2 obtained from the linear fitting between the metal work functions and the EWFs.
Multireference configuration interaction and perturbation theory without
reduced density matrices
Authors: Mahajan Ankit , Blunt Nick S. , Sabzevari Iliya , Sharma Sandeep
Published: December 2019

The computationally expensive evaluation and storage of high-rank reduced density matrices (RDMs) has been the bottleneck in the calculation of dynamic correlation for multireference wave functions in large active spaces. We present a stochastic formulation of multireference configuration interaction and perturbation theory that avoids the need for these expensive RDMs. The algorithm presented here is flexible enough to incorporate a wide variety of active space reference wave functions, including selected configuration interaction, matrix product states, and symmetry-projected Jastrow mean field wave functions. It enjoys the usual attractive features of Monte Carlo methods, such as embarrassing parallelizability and low memory costs. We find that the stochastic algorithm is already competitive with the deterministic algorithm for small active spaces, containing as few as 14 orbitals. We illustrate the utility of our stochastic formulation using benchmark applications.
Trapped-mode resonances in all-metallic metasurfaces comprising rectangular-hole dimers with broken symmetry
Authors: Yan Jing-chun , Li Zhi-kai , Zhang Yong , Wang Yu-lin , Huang Cheng-ping
Published: December 2019

Traditional metamaterial systems usually own a low Q factor due to the strong absorption and radiation loss. Fano resonances in ultrathin metasurfaces provide an efficient method for solving the issue. In this work, we theoretically and experimentally study the trapped-mode resonance in rectangular-hole dimers with broken symmetry. Compared to the asymmetric particle dimers that have been widely investigated, the asymmetric hole dimers in freestanding metal screens present an all-metallic platform for engineering the high-Q resonances. With the experiments, a significantly increased Q factor of ∼200 has been achieved in the microwave region. Numerical simulations show that, in comparison with the incident field, the hole electric field (and intensity) can be increased by ∼127 times (and ∼16 000 times). Moreover, the evolution characteristic of the trapped-mode resonance with the structural parameters has been studied systematically. The inversely quadratic relationship between the Q factor and asymmetric parameter, proposed primarily for the particle dimers [Koshelev et al., Phys. Rev. Lett. 121, 193903 (2018)], is found to work well for the asymmetric hole dimers.
Nonadiabatic quantum transition-state theory in the golden-rule limit. II. Overcoming the pitfalls of the saddle-point and semiclassical approximations
Authors: Fang Wei , Thapa Manish J. , Richardson Jeremy O.
Published: December 2019

We describe a path-integral molecular dynamics implementation of our recently developed golden-rule quantum transition-state theory (GR-QTST). The method is applied to compute the reaction rate in various models of electron transfer and benchmarked against the exact results. We demonstrate that for systems exhibiting two or more transition states, rates computed using Wolynes theory [P. G. Wolynes, J. Chem. Phys. 87, 6559 (1987)] can be overestimated by orders of magnitude, whereas the GR-QTST predictions are numerically accurate. This is the case both at low temperature, where nuclear tunneling makes a considerable contribution, and also in the classical limit, where only GR-QTST rigorously tends to the correct result. Analysis shows that the saddle-point approximation employed by Wolynes theory is not valid in this case, which results in the predictions of unphysical reaction pathways, while the energy constraint employed by GR-QTST resolves this problem. The GR-QTST method is also seen to give accurate results for a strongly anharmonic system by sampling configurations around the instanton pathway without making the semiclassical approximation. These promising results indicate that the GR-QTST method could be an efficient and accurate approach for simulating electron-transfer reactions in complex molecular systems.
Computational study on interactions between CO2 and (TiO2)n clusters at specific sites
Authors: Louis Hitler , Guo Ling-ju , Zhu Shuang , Hussain Sajjad , He Tao
Published: December 2019

The energetic pathways of adsorption and activation of carbon dioxide (CO2) on low-lying compact (TiO2)n clusters are systematically investigated by using electronic structure calculations based on density-functional theory (DFT). Our calculated results show that CO2 is adsorbed preferably on the bridge O atom of the clusters, forming a “chemisorption” carbonate complex, while the CO is adsorbed preferably to the Ti atom of terminal Ti−O. The computed carbonate vibrational frequency values are in good agreement with the results obtained experimentally, which suggests that CO2 in the complex is distorted slightly from its undeviating linear configuration. In addition, the analyses of electronic parameters, electronic density, ionization potential, HOMO−LUMO gap, and density of states (DOS) confirm the charge transfer and interaction between CO2 and the cluster. From the predicted energy profiles, CO2 can be easily adsorbed and activated, while the activation of CO2 on (TiO2)n clusters are structure-dependent and energetically more favorable than that on the bulk TiO2. Overall, this study critically highlights how the small (TiO2)n clusters can influence the CO2 adsorption and activation which are the critical steps for CO2 reduction the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.
Effects of soluble ions on hydration of calcined flue gas desulphurization gypsum
Authors: Lin Fu-xing , Zhong Yan-chi , Yan Shu-feng , Lin Bi-fan , Wang Jian-hua , Su Zhi-zhong
Published: December 2019

The influence of various water soluble cations (K+, Na+, Ca2+, Mg2+) on the hydration of calcined flue gas desulphurization gypsum was investigated. The results show that all cations but Ca2+ can accelerate the hydration of bassanite. The final crystal size is not largely influenced by different salts, except for Na+, where the giant crystal with length of >130 µm is observed. Current study clarifies the influence of different ions on the hydration of bassanite, which could provide sufficient guide for the pre-treatment of original flue gas desulphurization gypsum before actual application.
Tip of the iceberg
Authors: Pollack Henry
Published: December 2019

The conditions required for an object to float in a stable orientation sometimes lead to surprising results.
On-Resin Strategy to Label α-Conotoxins: Cy5-RgIA, a Potent α9α10 Nicotinic Acetylcholine Receptor Imaging Probe
Authors: Muttenthaler Markus , Nevin Simon T. , Inserra Marco , Lewis Richard J. , Adams David J. , Alewood Paul F.
Published: December 2019

In-solution conjugation is the most commonly used strategy to label peptides and proteins with fluorophores. However, lack of site-specific control and high costs of fluorophores are recognised limitations of this approach. Here, we established facile access to grams of Cy5-COOH via a two-step synthetic route, demonstrated that Cy5 is stable to HF treatment and therefore compatible with tert-butyloxycarbonyl solid phase peptide synthesis (Boc-SPPS), and coupled Cy5 to the N-terminus of α-conotoxin RgIA while still attached to the resin. Folding of the two-disulfide containing Cy5-RgIA benefitted from the hydrophobic nature of Cy5, resulting in only the globular disulfide bond isomer. In contrast, wild-type α-RgIA folded into the inactive ribbon and bioactive globular isomer under the same conditions. Labelled α-RgIA retained its ability to inhibit acetylcholine (100µM)-evoked current reversibly with an IC50 of 5.0nM (Hill coefficient=1.7) for Cy5-RgIA and an IC50 of 1.6 (Hill coefficient=1.2) for α-RgIA at the α9α10 nicotinic acetylcholine receptor (nAChR) heterologously expressed in Xenopus oocytes. Cy5-RgIA was then used to successfully visualise nAChRs in the RAW264.7 mouse macrophage cell line. This work introduced not only a new and valuable nAChR probe, but also a new versatile synthetic strategy that facilitates production of milligram to gram quantities of fluorophore-labelled peptides at low cost, which is often required for invivo experiments. The strategy is compatible with Boc- and 9-fluorenylmethoxycarbonyl (Fmoc)-chemistry, allows site-specific labelling of free amines anywhere in the peptide sequence, and can also be used for the introduction of Cy3/Cy5 fluorescence resonance energy transfer (FRET) pairs.