bluuebunny/crossref_metadata_2025 huggingface dataset:
Advantages, limitations, and future suggestions in studying graphene-based desalination membranes
Authors: Castelletto Stefania , Boretti Alberto
Published: February 2021

The potential advantages of novel 2D carbon materials are high water permeability, high selectivity capable of rejecting monovalent ions, with high salt rejection, reduced fouling, and high chemical and physical stability.
Atomic layer deposition of superparamagnetic ruthenium-doped iron oxide thin film
Authors: Tamm Aile , Tarre Aivar , Kozlova Jekaterina , Rähn Mihkel , Jõgiaas Taivo , Kahro Tauno , Link Joosep , Stern Raivo
Published: February 2021

In atomic layer deposited Ru-doped α-Fe2O3 thin films superparamagnetic behaviour of nanocrystallites is observed with the magnetic coercive force up to 3 kOe.
A transparent glycerol-hydrogel with stimuli-responsive actuation induced unexpectedly at subzero temperatures
Authors: Guo Meiling , Yan Jiao , Yang Xi , Lai Jingjuan , An Peng , Wu Yuanpeng , Li Zhenyu , Lei Weiwei , Smith Andrew T. , Sun Luyi
Published: February 2021

A novel strategy to synthesize a glycerol-hydrogel with outstanding anti-freezing and shape memory properties was developed. A glycerol-hydrogel actuator was fabricated to achieve a programmable actuating process at subzero temperatures.
Periodic event‐triggered consensus control for multi‐agent systems with switching jointly connected topologies
Authors: Sun Jian , Wang Zhanshan , Fan Xiaofei
Published: February 2021

The consensus problem for a class of multi‐agent systems with switching jointly connected topologies via periodic event‐triggered control is studied. The distinguishing feature of such system is that the eigenvalues of system matrix can contain positive real parts. Due to the coexistence of unstable system matrix and disconnected topologies, the agents can diverge from each other across some periods even if the control input is imposed on them. To overcome this difficulty, a periodic‐sampling time unit (PSTU) approach is introduced to analyse the local convergence or divergence property within each sampling time unit based on the periodic event‐triggering control. Then the stabilisation property of switching behaviours is utilised to compensate the divergence within each switching interval via the dwell time technique. It is interesting to see that each switching period is considered to consist of finite number of PSTUs. Then by confining a pair of lower and upper bounds on the dwell time, the overall consensus can be reached. Further, a novel class of event‐dependent discretised Lyapunov functions are utilised to describe the error characteristics and computable conditions for the overall consensus can be derived. Finally, the effectiveness of the proposed result is illustrated by a numerical example.
New results on stability for non‐linear Markov switched stochastic functional differential systems
Authors: Feng Lichao , Liu Lei , Cao Jinde , Xue Changfeng
Published: February 2021

For Markov switched stochastic functional differential systems (SFDSs), asymptotic property is one of the most desired issues. Recently, a new class of delay‐dependent asymptotic stability for non‐linear Markov switched SFDSs was investigated. However, the existing references do not take the convergent speed and non‐autonomous factor into consideration. Therefore, by means of multiple Lyapunov–Krasovskii functionals, this study is devoted to examine the exponential stability for highly non‐linear autonomous Markov switched SFDSs and the exponential stability, polynomial stability and polynomial growth at most for highly non‐linear non‐autonomous systems, where all the criteria rely on the intervals lengths of continuous delays. In addition, the properties of boundedness and asymptotic stability are as well explored.
Binary pathfinder algorithm for bus splitting optimisation problem
Authors: Doğan Erdi , Yörükeren Nuran
Published: February 2021

This study proposes a binary version of the pathfinder algorithm (BPFA) inspired by both the collective movement of animals and the leadership hierarchy of swarms in order to solve the existing bus splitting optimisation (BSO) problem encountered by transmission system operators. Some existing efficient algorithms, such as particle swarm optimisation, binary grey wolf optimiser, and salp swarm algorithms, are also utilised to obtain a suitable solution in the BSO problem and to compare it with the BPFA. The objective function of the BSO problem is built to restrict the short‐circuit current and to provide the N − 1 security criteria. A new mathematical approach is proposed so as to assess the security performance of the transmission system during the solving of the BSO problem. The efficacy of the proposed algorithm is tested on well‐known benchmark functions as well as IEEE 57 and IEEE 118 bus systems. Various transfer functions and position updating rules are implemented to each of the algorithms to acquire a better transition from continuous context to the binary format. The results obtained of the statistical indicators and the pairwise comparisons validate the efficiency and reliability of the BPFA algorithm in solving the compelling real‐world problem.
Optimal dispatching method based on actual ramp rates of power generation units for minimising load demand response time
Authors: Wei Mengyao , Yang Zijiang , Wang Jiandong , Gao Song , You Daning
Published: February 2021

This study proposes a method to determine optimal load demand changes of power generation units, in order to complete a total load demand change for power grids in the minimum response time. The main feature is to exploit the information of actual ramp rates, which are the maximum changing speeds of generated powers in practice from power generation units. The proposed method is composed of two steps. First, actual ramp rates are estimated from historical data based on the piece‐wise linear representations of generated powers. Second, optimal values of load demand changes are determined based on the solutions to an optimisation problem minimising the response time. A main challenge is on the uncertainties of estimated actual ramp rates and their effects on the response time. This challenge is resolved by exploiting Bayesian estimators to yield posterior probability distributions of the estimated actual ramp rates, from which the optimal response time and its confidence interval are obtained. Numerical examples are provided to support the proposed method and compare with existing methods.
ADMM‐based distributed response quantity estimation: a probabilistic perspective
Authors: Zhang Yufan , Ai Qian , Li Zhaoyu
Published: February 2021

With the wide deployment of smart meters in the end‐user side, demand response (DR) is gaining prominence. Estimating the potential response is a preliminary step to the DR implementation. However, how to select proper features, how to protect privacy, and how to capture the response uncertainty remains three challenges to the customer response potential estimation. This study provides a detailed response quantity estimation for each customer. The authors proposed a probabilistic response quantity estimation framework and solved the problem by alternating direction method of multipliers (ADMM) in a fully‐distributed way. In particular, by utilising a similar consumption pattern matching principle, the feature for each DR day of each customer is selected based on the matched DR participants. Then, the pinball loss‐guided ridge regression is formulated, so the quantiles are obtained to cope with the uncertainty. The training process can be solved by each customer at the local site in a fully‐distributed way, which protects the privacy and reduces the centralised processing burden. Finally, in the case study, the assumption behind a similar consumption pattern matching principle is validated empirically. Also, the proposed method is confirmed to have good convergence performance and can produce reasonable estimation results.
Interleaved non‐isolated DC–DC converter for ultra‐high step‐up applications
Authors: Fani Rezvan , Farshidi Ebrahim , Adib Ehsan , Kosarian Abdolnabi
Published: February 2021

This study presents a novel interleaved non‐isolated converter for ultra‐high step‐up applications. This circuit utilises coupled inductor and voltage‐lift techniques to achieve high voltage gain. In the proposed converter, the configuration of interleaved technique and winding‐cross‐coupled inductors not only reduces the input current ripple and current stress of semiconductor devices but also increases the voltage gain. Further, using voltage‐lift technique helps to reach a very high voltage conversion ratio with low turn ratio and proper duty cycle. Since the voltage stress of semiconductor devices is low enough, low on resistance switches and low voltage ultra‐fast recovery diodes are used. For this converter, high voltage gain, low conduction losses, low reverse recovery losses, high efficiency, low input current ripple, small volume and reduced cost are provided. Therefore, the proposed converter is a good choice for ultra‐high step‐up applications. The implemented 100 W laboratory prototype circuit with 18 V input voltage and unity turn ratio of coupled inductors reaches 360 V output voltage and 94.7% efficiency which validates the accuracy of theoretical analysis.
Leakage current minimisation in transformer‐less wide operating range interleaved minimum phase hybrid converter with improved AC output quality
Authors: Samal Simanta Kumar , Singh Rajeev Kumar , Mahanty Ranjit
Published: February 2021

This study proposes a transformer‐less interleaved minimum phase hybrid converter, which is capable of delivering both AC and DC outputs, with reduced leakage current for photovoltaic applications. As the conventional transformer‐less hybrid converters have the limitation of strong common‐mode leakage current, when they are connected to the grid or their neutral point is grounded, a hybrid unipolar‐based sinusoidal pulse‐width modulation technique is used in the proposed hybrid converter to minimise the total common‐mode voltage during its operation. Moreover, the proposed hybrid converter has a wide operating range of duty ratio (D) and modulation index (), i.e. it can operate at both the conditions and , unlike the conventional hybrid converters. Furthermore, the proposed hybrid converter exhibits minimum phase behaviour; which results in simpler controller design, high loading capability and fast dynamic response. In addition, it has improved output AC voltage quality because of operation at high values. The proposed hybrid converter also exhibits superior cross‐regulation during dynamic load change conditions. The performance of the proposed converter is compared with other similar topologies to bring out its advantages. Detailed mathematical modelling is carried out and a 900 W laboratory prototype is developed to verify its performance.
Influence of the rail electrification system topology on the energy consumption of train trajectories
Authors: Riego‐Martinez Jesus , Perez‐Alonso Marcelo , Duque‐Perez Oscar
Published: February 2021

Electrically powered rail vehicles are considered one of the most energy‐efficient means of transport. Transport activity is responsible for a considerable part of global energy consumption. The transport industry is therefore obliged to develop strategies for more efficient energy use. Railway electrification systems transmit the electrical power supplied by substations to moving trains. However, part of the power supplied is consumed by the electrification systems and does not reach the trains. In this study, transmission losses in the 2 × 25 kV electrification system are evaluated. The 2 × 25 kV system is widely used in high‐speed and high‐capacity railway lines. Assessment of the performance of the 2 × 25 kV system is carried out by computer simulation of the power flows between the elements involved in train movement by means of simplified physical models. The results show that the reduction of transmission losses is a feasible way to achieve energy savings and to improve the energy efficiency in electrified rail transport. For this, it is essential to add the topology of the electrification system to the data considered in the design of the train trajectories.
Stochastic bidding strategy of electric vehicles and energy storage systems in uncertain reserve market
Authors: Lu Shaofeng , Han Bing , Xue Fei , Jiang Lin , Feng Xue
Published: February 2021

This paper proposes an Electric Vehicle (EV) aggregator bidding strategy in the reserve market. The EV aggregator determines the charging/discharging operations of EVs in providing reserve service for profits maximization. In the Day‐Ahead Market (DAM), the EV aggregator submits a bidding plan to the Independent Systems Operator (ISO) including base‐load and reserve up/down capacities plans. In the Real‐Time Market (RTM), the EV aggregator should deploy reserve based on the ISO's requirements, and the EV aggregator could receive income by deploying reserve or penalty for reserve shortage. The stochastic programming method is applied to address the uncertain reserve deployment requirements in RTM. In addition, Energy Storage Systems (ESS) are utilized by the EV aggregator to enhance the ability in providing reserve service. The aggregator–owner contract is designed to guarantee EV owners' economic benefits. Case studies show the expected profits of the EV aggregator are maximized and the risk of the reserve shortage is well managed, i.e., penalty is minimized. With the utilization of ESS, the performance of the EV aggregator in making response to the ISO's requirements is improved. That is, the required reserve percentage increases from 5.68% to 7.85%, and the deployed reserve percentage increases from 69.71% to 88.47%.
SWOT analysis for orchestrated development of a solar railway system in China
Authors: Ji Li , Ning Fuwei , Ma Jing , Jia Limin
Published: February 2021

China has been the main source of global energy consumption growth for 18 years in a row. Railways account for a large proportion of China's energy consumption, and the greening of railway energy supply systems will be an irreversible trend over time. Using a SWOT analysis approach, the authors investigate the internal strengths and weaknesses and the external opportunities and threats for orchestrated development of a solar railway system in China. After discussing countermeasures and suggestions for integrated development of a solar railway system in China, the conclusion is drawn that the railway power system will be green, resilient, self‐contained and sustainable by utilising the existing space in the railway system for photovoltaic power generation, using hybrid energy storage facilities and energy internet technologies to balance power supply and railway energy demands, and grasping the strategic opportunity for domestic and foreign construction projects.
A reverse logistics inventory model with multiple production and remanufacturing batches under fuzzy environment
Authors: Sharma Swati , Singh Shiv Raj , Kumar Mohit
Published: February 2021

In the last few years, inventory modeling with reverse logistics has received more attention from both the academic world and industries. Most of the existing works in the literature believed that newly produced products and remanufactured products have the same quality. However, in many industries, customers do not consider remanufactured products as good as new ones. Therefore, this study develops a reverse logistics inventory model with multiple production and remanufacturing batches (cycles) under the fuzzy environment where the remanufactured products are of subordinate quality as compared to the newly produced products. As the precise estimation of inventory cost parameters such as holding cost, setup cost, etc. becomes often difficult; so these cost parameters are represented as triangular fuzzy numbers. Used products are purchased, screened and then suitable products are remanufactured. The production and remanufacturing rates are demand dependent. The main goal of this study is to obtain the optimal production and remanufacturing policy that minimizes the total cost per unit time of the proposed inventory system. The signed distance method is employed to defuzzify the total cost function. A numerical example is presented to demonstrate the developed model. Finally, sensitivity analysis is executed to study the impact of key parameters on the optimal solution.
Wie entwickeln sich die Kosten und Qualität der Behandlung?
Authors: Haufe Christoph C.
Published: February 2021

Die Autoren nehmen ausführlich und mit zahlreichen Beispielen illustriert die Personalsituation in Kliniken und Praxen ins Visier und entwickeln die nachfolgenden Kerngedanken.
Was sind die Besonderheiten bei Nierentransplantation und Gravidität?
Authors: Clement Deborah , Thorban Stefan , Matevossian Edouard
Published: February 2021

Mit einer Nierentransplantation (NTx) wird die Möglichkeit einer Schwangerschaft und Geburt eines Kindes für Frauen mit terminaler Niereninsuffizienz deutlich verbessert. Bereits 1963 wurde über die erste Patientin mit einer erfolgreichen Schwangerschaft nach NTx berichtet 1. Die Prävalenz, nach einer NTx schwanger zu werden, liegt im Mittel bei 24 %, und 2 % aller gebärfähigen Frauen nach NTx erreichen eine Schwangerschaft 2. Im vorliegenden Beitrag werden Studien und Erfahrungen zu diesem Thema ausgewertet sowie Empfehlungen und Risiken für die Patientin und ihr Kind zusammengefasst, entsprechend den Vorgaben der Studiengruppe „European Renal Best Practice“ 3, 4.
Veränderungen im Vorstand
Authors: Wiegard-Szramek Ina
Published: February 2021

2020 haben 2 wunderbare Gründe, die neugeborenen Zwillingsmädchen von Matthias Eikelmann, für eine Veränderung im Vorstand des fnb e. V. gesorgt. Matthias nimmt sich als 1. Vorsitzender eine Auszeit, um sich mehr um seine Familie kümmern zu können. Wir wünschen Matthias, seiner Frau und dem „großen“ Bruder alles Gute anlässlich des Familienzuwachses. Matthias bleibt als 2. Vorsitzender im Vorstand.
Wissenswertes zum Heilpraktikerberuf
Authors: Bierbach Elvira
Published: February 2021

Eine Zusammenfassung wichtiger und interessanter Informationen zum Heilpraktikerberuf.
Motivation zur Vollblutspende während pandemischer Ereignisse
Authors: Weidmann Christian , Derstroff Marie , Müller-Steinhardt Michael
Published: February 2021

Auch während Pandemien müssen die Blutspendedienste kontinuierlich BlutspenderInnen rekrutieren, um die Versorgung mit Blutprodukten zu gewährleisten. Während im Anschluss an andere Katastrophen wie Erdbeben oder Terroranschlägen die Spendebereitschaft meist sprunghaft ansteigt, zeigte sich in der Vergangenheit bei beginnenden Pandemien zunächst ein Rückgang des Spendenaufkommens. Viele SpenderInnen fürchten eine Infektion oder eine Schwächung ihres Immunsystems und bleiben zu Hause. Auch fällt es den Blutspendediensten zunächst schwer, die gewohnte Anzahl an mobilen Spendeterminen zu organisieren, wodurch das Spendenaufkommen zurückgeht. In der aktuellen SARS-CoV-2-Pandemie betrug dieser Rückgang in vielen Ländern mehr als 10%. SpenderInnen, die auch während einer Pandemie spenden, sind in der Regel erfahrener und besitzen bereits eine ausgebildete Spenderidentiät. Viele dieser SpenderInnen berichten, dass sie gezielt einen Beitrag zur Überwindung der Krise leisten möchten. Auch während einer Pandemie ist demnach eine hohe Solidarität unter BlutspenderInnen zu finden. Potenzielle ErstspenderInnen lassen sich durch die unsicheren Rahmenbedingungen dagegen von einer Spende eher abhalten und es bedarf gezielter Rekrutierungsstrategien unter Einsatz von Social-Media-Kanälen, um neue SpenderInnen zu gewinnen. Erste Befunde unter deutschen BlutspenderInnen lassen hierbei eine hohe Rückkehrintention der ErstspenderInnen erwarten. Um die Blutversorgung auch während einer Pandemie aufrechterhalten zu können, sollten die Blutspendedienste neben der Rekrutierung von ErstspenderInnen versuchen, schnell die Anzahl ihrer Spendetermine zu erhöhen. Die Ansprache bestehender SpenderInnen sollte vor allem die Verunsicherung reduzieren und das Vertrauen in die Blutspendedienste stärken. Je größer das Vertrauen in die Spendeeinrichtung ausfällt, desto geringer ist die Risikowahrnehmung der SpenderInnen. Auch sollten alternative Kontaktwege etwa über Messengerdienste getestet werden, da diese eine schnelle Ansprache erlauben.
Der Perikardersatz bei infizierter Aortenprothese
Authors: Bauer Martin , Biro Gabor , Busch Albert
Published: February 2021

Infizierte Kunststoffprothesen zählen zu den gravierendsten Komplikationen in der Gefäßchirurgie. Das OP-Team des Klinikums rechts der Isar schildert, wie eine infizierte Aortenprothese durch eine handgenähte Perikardprothese ersetzt wird.
Die konservative Therapie der Refluxkrankheit und ihre Grenzen
Authors: Labenz Joachim
Published: February 2021

Die gastroösophageale Refluxkrankheit (GERD) ist häufig. Protonenpumpeninhibitoren (PPI) gelten als Mittel der ersten Wahl für alle klinischen Manifestationen. Sie wirken allerdings bei mindestens 30% der Patienten unzureichend, zudem werden sie gelegentlich auch nicht vertragen. Einige Patienten wünschen sich auch eine therapeutische Alternative. Alginate bewirken eine mechanische Refluxhemmung durch Bildung einer gelartigen Schicht in der sog. Acid Pocket, einem Säurereservoir, das unmittelbar nach der Nahrungsaufnahme auf dem Speisebrei im Magenkorpus entsteht. Sie kommen zur Symptombehandlung einer unkomplizierten GERD als Alternative und bei unzureichendem PPI-Effekt auf die Symptome auch als Ergänzung zu einem PPI (add-on) in Betracht. Bei persistierenden Refluxbeschwerden sowie einer nicht heilenden Refluxösophagitis ist eine differenzierte endoskopische und funktionsanalytische Diagnostik zur Ursachenklärung erforderlich. Extraösophageale Manifestationen der
GERD, wie z. B. Husten, Räusperzwang, Stimmprobleme und Globusgefühl, sprechen häufig nicht auf eine Antirefluxtherapie an. Neue Daten sprechen dafür, dass es sich um komplexe Hypersensitivitätssyndrome handelt, bei denen Reflux nur einer von mehreren möglichen Auslösern ist.
Lumen-apposing metal stent through the meshes of duodenal metal stents for palliation of malignant jaundice
Authors: Mangiavillano Benedetto , Kunda Rastislav , Robles-Medranda Carlos , Oleas Roberto , Anderloni Andrea , Sportes Adrien , Fabbri Carlo , Binda Cecilia , Auriemma Francesco , Eusebi Leonardo H. , Frazzoni Leonardo , Fuccio Lorenzo , Colombo Matteo , Fugazza Alessandro , Bianchetti Mario , Repici Alessandro
Published: February 2021

Background and study aims Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard procedure for malignant jaundice palliation; however, it can be challenging when a duodenal self-expandable metal stent (SEMS) is already in place.

Patients and methods The primary aim of our study was to evaluate the technical feasibility of the placement of a lumen apposing metal stent (LAMS) through the mesh (TTM) of duodenal stents. The secondary aims were to evaluate clinical outcomes and adverse events (AEs) related to the procedures.

Results Data from 23 patients (11 F and 12 M; mean age: 69.5 ± 11 years old) were collected. In 17 patients (73.9 %) TTM LAMS placement was performed as first intention, while in six patients (26.1 %) it was performed after a failed ERCP. Thirteen patients (56.5 %) underwent the procedure due to advanced pancreatic head neoplasia. One technical failure was experienced (4.3 %). The TTM LAMS placement led to a significant decrease in the serum levels of bilirubin, ALP, GGT, WBC and CRP. No cases of duodenal SEMS occlusion occurred and no other AEs were observed during the follow-up.

Conclusions Concomitant malignant duodenal and biliary obstruction is a challenging condition. Palliation of jaundice using TTM LAMS in patients already treated with duodenal stent is associated to promising technical and clinical outcomes.
Nachruf auf Prof. Dr. Lothar Schmidt (*9.06.1936 – †30.10.2020)
Authors: Scheer Jörn
Published: February 2021

Vor 50 Jahren wurde das Medizinstudium tiefgreifend neu geordnet: Die
Approbationsordnung von 1970 löste die Bestallungordnung von 1953 ab und
führte v. a. mehrere sog. psychosoziale Fächer in das Curriculum
ein: Psychosomatik, Psychotherapie, Medizinische Psychologie, Medizinische
Soziologie, Sozialmedizin. Da sich die Psychologischen Institute an den
Universitäten nicht in der Lage sahen, die große Menge an
Studierenden der Medizin in einem Pflichtfach zu unterrichten, wurde dies von den
zahlreich in den universitären medizinischen Einrichtungen arbeitenden
Psychologinnen und Psychologen und psychologisch ausgebildeten Ärztinnen und
Ärzten übernommen. Deren fachliche Orientierung war entsprechend
heterogen. Einige standen in einer psychoanalytischen Tradition, andere waren
empirisch-psychologisch ausgebildet in der damals noch relativ neuen Ausrichtung,
andere kamen aus der medizinischen Praxis. Auch die medizinischen Fakultäten
verfolgten unterschiedliche Konzepte. Einige siedelten das Fach in der vorklinischen
Grundausbildung an, andere sahen die Medizinische Psychologie eher als
„klinisches“ Fach mit entsprechenden Versorgungsaufgaben an.
A pilot study of virtual reality as an alternative to pharmacological sedation during colonoscopy
Authors: Friedman Madeline , Rand Kyle , Patel Tobias , Colizzo Francis , Carolan Peter , Kelsey Peter , Chung Daniel C.
Published: February 2021

Background and study aims Conscious sedation is routinely administered for colonoscopy but is associated with risks and inconveniences. We sought to determine whether virtual reality (VR) may be a feasible alternative.

Patients and methods Twenty-seven individuals scheduled for screening/surveillance colonoscopy participated. The VR device was activated throughout the colonoscopy, but subjects could opt out and request standard medications. Questionnaires were administered, and variables were assessed on a scale of 1 to 10.

Results Cecal intubation was achieved in all cases without adverse events (AEs). Study colonoscopies were completed without pharmacological rescue in 26 of 27 patients (96.3 %) and procedure times were comparable to baseline. Subjects reported minimal pain, high satisfaction, and willingness to use VR for future colonoscopies to avoid narcotics and resume normal activities including driving.

Conclusion Replacing pharmacological sedation with VR did not impact colonoscopy completion rates, procedure time, or AEs. Satisfaction was high and only one subject (3.7 %) chose to suspend VR. VR can be an effective alternative for patients undergoing colonoscopy who prefer to avoid narcotics.
Das Heilpraktikerwesen aus der Perspektive der Rechtswissenschaft
Authors: Sodan Helge , Hadank Bernhard
Published: February 2021

Der Berufsstand der Heilpraktiker deckt mit seinen zahlreichen Ausprägungen ein breites Spektrum verschiedener Versorgungsformen ab. Seine rechtliche Absicherung ist jedoch defizitär. Mit einer Studie haben der Rechtswissenschaftler Professor Dr. Helge Sodan und dessen wissenschaftlicher Mitarbeiter Bernhard Hadank eingehend untersucht, wo der Gesundheitspolitik bei der Reformgesetzgebung rechtliche Grenzen gesetzt sind und welche Möglichkeiten bestehen, in Zukunft das Heilpraktikerwesen rechtlich abzusichern.
Qualität der Versorgung sehr kleiner Frühgeborener in Deutschland – Auswertung öffentlich verfügbarer Daten der Perinatalzentren von 2014 bis 2018
Authors: Trotter Andreas
Published: February 2021

Hintergrund Seit 2014 werden Ergebnisdaten der Versorgung sehr kleiner Frühgeborener (FG) in Deutschland zentral erfasst und sind unter www.perinatalzentren.org abrufbar. Mit den online verfügbaren Daten soll der Zusammenhang zwischen Fallzahl und Ergebnisqualität untersucht werden.

Methoden Bei der Ergebnisveröffentlichung für den 5-Jahreszeitraum 2014–2018 werden die Fallzahl pro Perinatalzentrum und Überleben bzw. Überleben ohne schwere Erkrankungen in Relation zum Bundesdurchschnitt für FG<1500 g Geburtsgewicht ausgewiesen. Neben der Fallzahl wird auch eine nach Risikofaktoren adjustierte Fallzahl ausgewiesen. Mittels Regression wurde der Zusammenhang zwischen Fallzahl, adjustierter Fallzahl und Überlebenswahrscheinlichkeit untersucht.

Ergebnisse Von den 212 Perinatalzentren waren 163 (77%) als Level 1 und 49 (23%) als Level 2 Zentren gelistet und versorgten 9300 (94%; Median 51; Min 13 bis Max 186) bzw. 538 (6%; 9; 4–28) FG<1500 g pro Jahr. Für die Fallzahl ließ sich keine signifikante Korrelation mit der Überlebenswahrscheinlichkeit nachweisen. Die adjustierte Fallzahl zeigte einen schwachen linearen Zusammenhang mit dem Überleben ohne schwere Erkrankungen (p=0,02; R2=0,03). Bei nicht-parametrischer Regression stellten sich signiﬁkante Effekte ab einer adjustierten Fallzahl von mehr als 170 (Überleben) bzw. 100 (Überleben ohne schwere Erkrankungen) FG pro Jahr und Zentrum ein. Im Bereich darunter erklärt die Fallzahl keinen Anteil der Streuung.

Schlussfolgerung Es findet sich nur ein schwacher linearer und nichtlinearer Zusammenhang zwischen adjustierter Fallzahl und relativer Überlebenswahrscheinlichkeit, der maßgeblich durch sehr große Zentren getrieben ist.
Management of Patent Vitellointestinal Duct in Infants
Authors: Ghritlaharey Rajendra K.
Published: February 2021

Objectives

This study was undertaken to investigate and review the clinical presentation, surgical procedures executed, and the final outcome of infants managed for the patent vitellointestinal duct.

Materials and Methods

This is a single-institution, retrospective study and included infants who were operated for the patent vitellointestinal duct. This study was conducted at author's Department of Paediatric Surgery during the last 20 years; from January 1, 2000 to December 31, 2019.

Results

A total of 24 infants were operated for the patent vitellointestinal duct during the study period and comprised 20 (83.3%) boys and 4 (16.6%) girls. The age of infants ranged from 7 days to 10 months, with a mean of 88.41 ± 64.9 days. Twenty-three (95.8%) infants were operated within 6 months of the age, 17 (70.8%) of them were operated within 3 months of the age. Only one (4.1%) infant was operated at the age of 10 months. Among 24 infants, 13 (54.1%) were presented with features suggestive of acute intestinal obstruction and remaining 11 (45.8%) were presented with fecal discharges through the umbilicus without intestinal obstruction. Among 13 infants who presented with acute intestinal obstruction, 12 had prolapsed bowel and 6 of them also had gangrenous bowel. Operative procedures were executed (n = 24) in the following order of frequency: (1) resection of patent vitellointestinal duct, wide wedge resection of ileum, and ileal repair (n = 13, 54.1%); (2) resection of patent vitellointestinal duct, small segment of ileum, and ileoileal anastomosis (n = 9, 37.5%); and (3) resection of patent vitellointestinal duct, segment of ileum, and an ileostomy (n = 2, 8.33%). Postoperatively, two (8.3%) infants developed anastomotic leak and peritonitis one each, later on, both of them died.

Conclusion

Patent vitellointestinal duct not only present with fecal discharges through the umbilicus but half of the infants presented with prolapsed bowel and with features of acute small bowel obstruction. Delay in seeking treatment for such cases was associated with considerable morbidity and mortality and therefore the patent vitellointestinal duct should be excised at the earliest.
Migrating Lateral Ventricle Choroid Plexus Cyst into the Fourth Ventricle Causing Acute Hydrocephalus
Authors: Carter Lacey M. , Cornwell Benjamin , Gross Naina L.
Published: February 2021

Choroid plexus cysts consist of abnormal folds of the choroid plexus that typically resolve prior to birth. Rarely, these cysts persist and may cause outflow obstruction of cerebrospinal fluid. In this article, we presented a 5-month-old male child patient who presented with lethargy, vomiting, and a bulging anterior fontanelle. Magnetic resonance imaging showed one large choroid plexus cyst had migrated from the right lateral ventricle through the third ventricle and cerebral aqueduct into the fourth ventricle causing outflow obstruction. The cyst was attached to the lateral ventricle choroid plexus by a pedicle. The cyst was endoscopically retrieved from the fourth ventricle intact and then fenestrated and coagulated along with several other smaller cysts. Histologic examination confirmed the mass was a choroid plexus cyst. The patient did well after surgery and did not require any cerebrospinal fluid diversion. Nine months after surgery, the patient continued to thrive with no neurological deficits. This case is the first we have found in the literature of a lateral ventricular choroid plexus cyst migrating into the fourth ventricle and the youngest of any migrating choroid plexus cyst. Only three other cases of a migrating choroid plexus cyst have been documented and those only migrated into the third ventricle. New imaging advances are making these cysts easier to identify, but may still be missed on routine sequences. High clinical suspicion for these cysts is necessary for correct treatment of this possible cause of hydrocephalus.
Practice Patterns of Central Venous Catheter Placement and Confirmation in Pediatric Critical Care
Authors: Veten Ahmed , Davis Joshua , Kavanagh Robert , Thomas Neal , Zurca Adrian
Published: February 2021

Optimal practices for the placement of central venous catheters (CVCs) in critically ill children are unclear. This study describes the clinical practice of pediatric critical care medicine (PCCM) providers regarding CVC placement, including site selection, confirmation practices and assessment of complications. Two-hundred fourteen PCCM providers responded to an electronic survey, including 170 (79%) attending physicians, 30 (14%) fellow physicians, and 14 (7%) advanced practice providers. PCCM providers most commonly place internal jugular (IJ) and femoral CVCs, with subclavian CVCs and peripherally inserted central catheters (PICCs) placed less commonly (IJ 99%, femoral 95%, subclavian 40%, PICC 19%). The IJ is the most preferred site (128/214 (60%)); decreased infection risk is the most common reason for preferring this site. The subclavian is the least preferred site (150/214 [70%]) due to concern for increased risk of complications (51%) and personal discomfort with the procedure (49%). One-hundred twenty-six (59%) of respondents reported receiving formal ultrasound (US) or echocardiography training. Respondents reported using dynamic US guidance for placement in 90% of IJ, 86% of PICC, 78% of femoral, and 12% of subclavian CVCs. Plain radiography (X-ray) was the most preferred modality for confirming CVC tip position (85%) compared with US (9%) and no imaging (5%). Most providers reported using X-ray to evaluate for pneumothorax following upper extremity CVC placement, with only 5% reporting use of US and none relying on physical exam alone. This study demonstrates wide variability in PCCM providers' CVC placement practices. Potential training gaps exist for placement of subclavian catheters and use of US.
Carnitine-Acylcarnitine Translocase Deficiency Masked by Extreme Prematurity
Authors: Lund Kelli C. , Scottoline Brian , Jordan Brian K.
Published: February 2021

Carnitine-acylcarnitine translocase (CACT) deficiency is a rare disorder of long chain fatty acid oxidation with a very high mortality rate due to cardiomyopathy or multiorgan failure. We present the course of a very premature infant with early onset CACT deficiency complicated by multiple episodes of necrotizing enterocolitis, sepsis, and liver insufficiency, followed by eventual demise. The complications of prematurity, potentiated by the overlay of CACT deficiency, contributed to the difficulty of reaching the ultimate diagnosis of CACT deficiency.
Knowledge, Awareness, Attitude, and Opinion about Application of Dental Stem Cells: A Dental School-Based Questionnaire Study
Authors: Subba Tarona Azem , Talwar Avaneendra , Anegundi Raghavendra Vamsi , Ashok Karishma , Ramesh Amitha , Thomas Biju
Published: February 2021

Objective The aim of the study is to assess the knowledge, awareness, attitude, and opinion concerning dental stem cells among faculty, postgraduates, and interns in a dental school.

Materials and Methods A questionnaire consisting of 12 questions was circulated among the 150 participants (50 faculty, 50 postgraduate students, and 50 interns). A questionnaire was prepared that could assess the basic knowledge on stem cells (dental) based on similar previous studies. The questionnaire data were entered by the investigator in Microsoft Excel 2010 on a corresponding day. Using Predictive Analytics Tools (Version 18), the analysis was done. Probability ratios by Pearson were used to analyze the application of knowledge, perception regarding stem cells.

Results The survey participants consisted of ~73% of females and 27% of males. Most of the participants have come across the term stem cells and thought that only pulp stem cells signified the only source of dental stem cells. The majority of the participants pointed out the anticipated high cost to be the biggest obstacle to a patient accepting regenerative dental treatment by stem cells.

Conclusion This study reveals a good level of knowledge among dental professionals, and it also showed the need to develop more awareness about the advancements in applications and banking.
Geometric machine learning algorithm helps sieve through structural data of tiny biological objects
Authors: McConnon Aili
Published: February 2021

By fusing manifold embedding with machine learning, the researchers create an algorithm that can pick out X-ray diffraction patterns of single particles from an ocean of data.
Performance and simulated moment uncertainties of an ion spectrometer with asymmetric 2π field of view for ion measurements in space
Authors: Su B. , Kong L. G. , Zhang A. B. , Klecker B. , Escoubet C. P. , Kataria D. O. , Dai L.
Published: February 2021

Space plasma instruments provide 3D particle velocity distribution functions. Because of telemetry limitations, these cannot be transmitted in high time resolution and the plasma needs to be characterized by moments of the velocity distribution function. These moment uncertainties have vital effects on the reliability and accuracy of onboard plasma moments. We assess the measurement accuracy for magnetosheath and solar wind ions using an ion spectrometer with an asymmetric field of view designed for the all-sky measurement of low-energy ions in the magnetosheath and solar wind. We focus on moment uncertainties for the ideal spectrometer, not considering the background counts, which may have considerable effects on the uncertainties in real life. To obtain number density, bulk velocity, and temperature, different orders of moments are integrated assuming a Maxwellian velocity distribution. Based on the design specifications, we use simulations to estimate systematic and random errors for typical plasma conditions. We find that the spectrometer resolution is adequate for determining the density of solar wind (∼7% error) and magnetosheath ions (∼4% error). The resolution is also adequate for determining the temperature of solar wind (∼10% error) and magnetosheath ions (∼2% error). For high speed flows with a bulk velocity of 750 km/s and a temperature of 20 eV, the maximum density and temperature errors become 9% and 7%, respectively. The bulk velocity errors are less than 2% for all cases. The contributions of heavy ions to the systematic errors are less than 5% for magnetosheath ions and less than 8% for solar wind ions.
Detecting handedness of spatially oriented molecules by Coulomb explosion imaging
Authors: Saribal Cem , Owens Alec , Yachmenev Andrey , Küpper Jochen
Published: February 2021

We present a new technique for detecting chirality in the gas phase: Chiral molecules are spatially aligned in three dimensions by a moderately strong elliptically polarized laser field. The momentum distributions of the charged fragments, produced by laser-induced Coulomb explosion, show distinct three-dimensional orientation of the enantiomers when the laser polarization ellipse is rotated by a non-right angle with respect to the norm vector of the detector plane. The resulting velocity-map-image asymmetry is directly connected to the enantiomeric excess and to the absolute handedness of molecules. We demonstrated our scheme computationally for camphor (C10H16O), with its methyl groups as marker fragments, using quantum-mechanical simulations geared toward experimentally feasible conditions. Computed sensitivity to enantiomeric excess is comparable to other modern chiroptical approaches. The present method can be readily optimized for any chiral molecule with an anisotropic polarizability tensor by adjusting the polarization state and intensity profile of the laser field.
Study of loss mechanisms on Sb2(S1−xSex)3 solar cell with n–i–p structure: Toward an efficiency promotion
Authors: Ayala-Mató F. , Vigil-Galán O. , Nicolás-Marín M. M. , Courel Maykel
Published: February 2021

In this work, a theoretical study on the impact of loss mechanisms on Sb2(S1−xSex)3 solar cells with a 10% certified world record efficiency is presented. In particular, it is found that CdS/Sb2(S1−xSex)3 interface recombination is the main loss mechanism, giving rise to a Voc deficit of almost 50% and a reduction in the efficiency of 45% compared to results obtained under the ideal radiative regimen. Under this mechanism, experimental observations, such as the J–V curve, efficiency, short-circuit current density, open-circuit voltage, fill factor, and external quantum efficiency, are reproduced. Finally, a discussion on the path to further promote device efficiency is presented and discussed.
Split Ga vacancies in n-type and semi-insulating β-Ga2O3 single crystals
Authors: Karjalainen A. , Makkonen I. , Etula J. , Goto K. , Murakami H. , Kumagai Y. , Tuomisto F.
Published: February 2021

We report a positron annihilation study using state-of-the-art experimental and theoretical methods in n-type and semi-insulating β-Ga2O3. We utilize the recently discovered unusually strong Doppler broadening signal anisotropy of β-Ga2O3 in orientation-dependent Doppler broadening measurements, complemented by temperature-dependent positron lifetime experiments and first principles calculations of positron–electron annihilation signals. We find that split Ga vacancies dominate the positron trapping in β-Ga2O3 single crystals irrespective of the type of dopant or conductivity, implying concentrations of at least 1×1018 cm−3.
Achieved limit thermal conductivity and enhancements of mechanical properties in fluorite RE3NbO7 via entropy engineering
Authors: Chen Lin , Wang Yitao , Hu Mingyu , Zhang Luyang , Wang Jiankun , Zhang Zhibin , Liang Xiubing , Guo Jun , Feng Jing
Published: February 2021

Effective governance of thermal conductivity and other properties is of significant interest for science, including the fields of thermal barrier coatings, thermoelectric materials, and limit alloys. In this study, we investigated the impact of entropy engineering on properties of fluorite RE3NbO7, and limit thermal conductivity and strengthened mechanical properties are achieved. The solution strengthening mechanism leads to an 80% increase in toughness when the intrinsic stiffness and Young's modulus of the fabricated samples are identified via nanoindentation. Thermal conductivity is as low as 1.03–1.17 W m−1 K−1 at 25–900 °C, drastically reducing the gap between experimental results and theoretical limit values of fluorite RE3NbO7. The limit thermal conductivity as well as enhanced thermal expansion coefficients (11.2 × 10−6 K−1) and mechanical properties imply that the working performance of RE3NbO7 is evidently promoted by entropy engineering.
Aluminum textile-based binder-free nanostructured battery cathodes using a layer-by-layer assembly of metal/metal oxide nanoparticles
Authors: Nam Donghyeon , Kwon Minseong , Ko Yongmin , Huh June , Lee Seung Woo , Cho Jinhan
Published: February 2021

Despite considerable interest in textile-based battery electrodes with large surface areas and mechanical flexibility, issues have restricted further advances in the energy performance of textile electrodes. These issues include the ineffective incorporation of conductive and/or active components into textile frameworks, the poor charge transfer between energy materials, and the formation of numerous unstable interfaces within textile electrodes. Herein, we introduce an aluminum textile-based lithium-ion battery cathode with remarkable areal capacity, high rate performance, and good cycling stability. Ligand exchange reaction-induced layer-by-layer (LbL) assembly of metal nanoparticles and small molecule linkers, with subsequent metal electroplating, perfectly converted polyester textiles to 3D-porous aluminum textiles that can be used as current collectors and high-energy reservoirs. The consecutive LbL assembly of high-energy LiFePO4 and conductive indium tin oxide nanoparticles onto the aluminum textiles using small organic linkers significantly increased the areal capacity and cycling stability (at least 580 cycles) of the resultant cathode, allowing facile charge transfer within the textile electrodes. Furthermore, the areal capacity of these textile electrodes increased from 1.07 to 3.28 mA h cm−2, with an increase in the folding number from 0 to 2.
RPA-mediated recruitment of Bre1 couples histone H2B ubiquitination to DNA replication and repair
Authors: Liu Guangxue , Yan Jiaqi , Wang Xuejie , Chen Junliang , Wang Xin , Dong Yang , Zhang Simin , Gan Xiaoli , Huang Jun , Chen Xuefeng
Published: February 2021

Significance

In eukaryotes, the monoubiquitination of histone H2B (H2Bub) plays a critical role in shaping chromatin structure, dynamics, and function. This modification is essential for proper DNA replication, repair, and transcription, but how H2Bub is evoked during these processes is unknown. Here, we found that the single-stranded DNA sensor RPA recruits Bre1, the ubiquitin E3 ligase for H2Bub, to replication forks or DNA breaks to stimulate local H2Bub. We show that RPA-mediated Bre1 recruitment is essential to promote DNA replication and repair by homologous recombination while suppressing mutations and genome instability. Thus, we reveal that RPA couples H2Bub to DNA replication and repair and controls the spatial–temporal distribution of H2Bub on chromatin.
Cylindrical spikes
Authors: Moughal M Z A , Lim W C
Published: February 2021

The Geroch/Stephani transformation is a solution-generating transformation, and may generate spiky solutions. The spikes in solutions generated so far are either early-time permanent spikes or transient spikes. We want to generate a solution with a late-time permanent spike. We achieve this by applying Stephani’s transformation with the rotational Killing vector field (KVF) of the locally rotationally symmetric Jacobs solution. The late-time permanent spike occurs along the cylindrical axis. Using a mixed KVF, the generated solution also features a rich variety of transient structures. We introduce a new technique to analyse these structures. Our findings lead us to discover a transient behaviour, which we call the overshoot transition. These discoveries compel us to revise the description of transient spikes.