bluuebunny/crossref_metadata_2025 huggingface dataset:
A combined experimental–numerical approach for permeability characterization of engineering textiles
Authors: Schmidt Tim , May David , Duhovic Miro , Widera Aaron , Hümbert Martina , Mitschang Peter
Published: May 2021

Extensive experimental test programs are required for the characterization of textile permeability, which is essential for the design of liquid composite molding processes. In this study, an experimental–numerical approach is presented, aiming to partially substitute experiments by numerical simulations. This approach uses 3D microscale simulations to evaluate the permeability within rovings and attribute these values to statistical volume elements of the textile at the mesoscale. To further improve accuracy, a calibration method has been defined. In order to validate the functionality of this approach the permeability of a glass fiber woven and a non‐crimp fabric at fiber volume contents (FVCs) between 50 and 60% were predicted. For the non‐calibrated but virtually compacted models with FVCs of 55 and 60%, the deviation ranges from −27% to +42%. This seems acceptable considering the typical scatter in experimental tests, for example, a CV of 20–50% was measured in recent permeability benchmarks. The numerically determined permeability was then used as input for numerical filling simulations at part level (macroscale). The resulting filling times were then compared to results of simulations based on experimental input values.
Syrian trajectories of exile in Lebanon and Turkey: Context of reception and social class
Authors: Bélanger Danièle , Ouellet Myriam , Saraçoğlu Cenk
Published: May 2021

Research on refugee trajectories rarely takes into account social class. Yet migration options for those fleeing conflicts and insecurity are more or less dangerous, desirable and doable and differences in trajectories have to do with people's ability to mobilise resources at a given time and in a given space. Based on 42 semistructured interviews conducted with Syrians who fled to Lebanon and Turkey between 2012 and 2017, this article focuses on how trajectories of exile are shaped by the interactions between social class and the specificities of the context of reception. These countries are similar to the extent that they both border Syria and host the largest numbers of Syrian refugees worldwide. Yet their respective policies, as well as their unique historical, legal and socio‐economic contexts, create different impacts on refugee trajectories and refugees' experience of inequality. We argue that as a result of the different contexts of reception for Syrians in Lebanon and Turkey, refugees' strategies to reduce precarity also differ significantly. As such, the relevance and usefulness of any given form of capital vary. Results indicate that survival strategies and mobilisation of capital in Lebanon revolve around obtaining legal status, whereas in Turkey, where all Syrian refugees benefit from legal status under the temporary protection regime, capital is mainly used to negotiate an exploitative labour market. Our study challenges conventional class analyses that imply direct links between the possession of economic and social capital and favourable trajectories of exile.
Thermally Robust High‐Resistance Layers on Low‐Resistance Silicon Synthesized by Molecular CO+ Ion Implantation
Authors: Popov Vladimir P. , Tarkov Sergey M. , Tikhonenko Fedor V. , Antonov Valentin A. , Tyschenko Ida E. , Simakin Sergey G. , Rudenko Konstantin V.
Published: May 2021

Using nanoscale inclusions of a wide‐band SiC semiconductor and SiO2 dielectric formed in CO+ molecular ion‐implanted (COII) layers allows creating highly resistive regions inside a moderate‐doped silicon substrate. Contrary to the well‐known implanted proton or argon‐ion insulation, where the high resistance is provided by the unstable radiation defect Fermi‐level pinning, such two‐type antidots form a bend of the silicon bandgap on the heteroboundaries around them, similar to the insulating layer in the p−n junction, and guarantee the absence of mobile charge carrier transport at a certain concentration of antidots and working temperatures below 400 K. These insulating regions save their properties even after hard thermal treatment (1400 K). Moreover, a gas blistering suppression is observed for the silicon‐on‐insulator (SOI) wafers with an ultrathin (10–40 nm) buried oxide (BOX). SIMS measurements demonstrate the strong mobile impurity accumulation at the COII region during subsequent thermal treatments.
Efficient p‐Doping with F6TCNNQ for Improving Performance of Polymer Photodetectors with Photomultiplication
Authors: Wang Jian , Chen Jun , Hu Haixia , Yin Hang , Xiao Jing , Zhang Lian
Published: May 2021

Polymer photodetectors with photomultiplication (PM‐PPDs) are prepared with PC71BM:P3HT (1:100, wt/wt) active layers containing efficient hole‐transport channels and large amount of isolated electron traps. The solid additive F6TCNNQ is incorporated into PC71BM:P3HT blend films with rather low content of 0.02 wt%. The external quantum efficiency (EQE) and response speed of PM‐PPDs with F6TCNNQ additive in the active layer are much larger than those of PM‐PPDs without F6TCNNQ additive under the same bias. The EQE values at 400 and 625 nm can reach 5240% and 3050% for the PM‐PPDs with F6TCNNQ in active layers under −9 V bias, which is among the highest values for PM‐PPDs under the same bias. The performance improvement of PM‐PPDs with F6TCNNQ is primarily ascribed to the enhanced hole mobility in the active layer, leading to the increased response speed with rise time of 27.7 ms and fall time of 85 ms. This work indicates that performance of PM‐PPDs can be markedly enhanced by using p‐doping with strong oxidizing agents, beneficial for an enhancement in hole mobility in F6TCNNQ:PC71BM:P3HT active layers.
Giant Anomalous Hall Conductivity in the Itinerant Ferromagnet LaCrSb3 and the Effect of f‐Electrons
Authors: Kumar Nitesh , Lamba Neetu , Gayles Jacob , Le Congcong , Vir Praveen , Guin Satya N. , Sun Yan , Felser Claudia , Shekhar Chandra
Published: May 2021

Itinerant ferromagnets constitute an important class of materials wherein spin polarization can affect the electric transport properties in nontrivial ways. One such phenomenon is anomalous Hall effect which depends on the details of the band structure such as the amount of band crossings in the valence band of the ferromagnet. Here, extraordinary anomalous Hall effect is found in an itinerant ferromagnetic metal LaCrSb3. The rather 2D nature of the magnetic subunit imparts large anisotropic anomalous Hall conductivity of 1250 Ω−1 cm−1 at 2 K. The investigations suggest that a strong Berry curvature by abundant momentum‐space crossings and narrow energy‐gap openings are the primary sources of the anomalous Hall conductivity. An important observation is the existence of quasi‐dispersionless bands in LaCrSb3 which is now known to increase the anomalous Hall conductivity. After introducing f‐electrons, anomalous Hall conductivity experiences more than twofold increase and reaches 2900 Ω−1 cm−1 in NdCrSb3.
Super‐Assembled Hierarchical CoO Nanosheets‐Cu Foam Composites as Multi‐Level Hosts for High‐Performance Lithium Metal Anodes
Authors: Zhang Runhao , Li Yong , Wang Meng , Li Dongwei , Zhou Junjie , Xie Lei , Wang Tao , Tian Wei , Zhai Yanjie , Gong Hongyu , Gao Meng , Liang Kang , Chen Pu , Kong Biao
Published: May 2021

Achieving uniform lithium (Li) deposition is the key to tackle uncontrollable dendrite growth, which hinders the application of Li metal anodes. In this study, molten Li is thermally injected into a 3D framework by growing lithiophilic CoO nanosheets on Cu foam (CF). The CoO layer grown on the CF surface physically adsorbs molten Li, which makes it possible to spontaneously wet the framework. The morphology of CoO nanosheets does not change during the Li injection process and formed a multi‐level structure with the CF, which is difficult to be achieved previously, as most lithiophilic oxides undergo serious chemical changes due to chemical reaction with Li and cannot provide a stable submicron structure for the subsequent Li stripping/plating process. The super‐assembled multi‐level structure provides abundant Li nucleation sites and electrolyte/electrode contact areas for rapid charge transfer in the composite anode. Therefore, the prolonged lifespan of symmetrical cells for 300 cycles at 10 and 10 mAh cm−2 with lower polarization is achieved, which further renders the LiFePO4 and Li4Ti5O12 based full cells with improved capacity retention up to 87.3% and 80.1% after 500 cycles at 1 C. These results suggest that the composite anode has a great application prospect.
Ultrasensitive and stable all graphene field‐effect transistor‐based Hg2+ sensor constructed by using different covalently bonded RGO films assembled by different conjugate linking molecules
Authors: Sun Mingyuan , Zhang Congcong , Chen Duo , Wang Jian , Ji Yanchen , Liang Na , Gao Haoyang , Cheng Shanshan , Liu Hong
Published: May 2021

As "molecular bridge," coupling agents can not only realize the covalent connection of composites, but also affect their properties, thus affecting the properties of devices based on them. Herein, leveraging differences in charge conduction properties of the (3‐aminopropyl)trimethoxysilane and 5,10,15,20‐tetrakis(4‐aminophenyl)‐21H,23H‐porphine caused by conjugacy structural differences, two kinds of layer‐by‐layer assembled smart carbon materials with different electrical properties are obtained at the same reduction temperature. The two graphene ultrathin films are then “planted” on Si/SiO2 substrates, respectively, as semiconductor layer and source/drain electrodes to fabricate an ultra‐stable all‐graphene field effect transistor (AG‐FET). Enabled by the covalent functionalized configuration and the functionally diverse of coupling agents, the AG‐FET obtained by this simple method won the high electrical characteristics, the hole, electron mobility, and the shelflife could reach 3.79 cm2/(V·s), 3.78 cm2/(V·s), and 18 months, respectively. In addition, good material stability and excellent device structure endow the device exceptional stability, electrical stability, and solvent resistance, improving its application prospect in solution phase sensing/detection. Such characteristics could be used to sense, transduce, and respond to external stimuli, especially in solution phase to monitor the important analytes, such as Hg2+ in a flowing sewage environment. We believe that such easy‐to‐manufacture AG‐FETs with ultrahigh performance and ultrahigh stability could also show great application prospects in other significant fields.
Investigation of the Selectivity of Carrier Transport Layers in Wide‐Bandgap Perovskite Solar Cells
Authors: Kavadiya Shalinee , Onno Arthur , Boyd Caleb C. , Wang Xingyi , Cetta Alexa , McGehee Michael D. , Holman Zachary C.
Published: May 2021

Excellent contact passivation and selectivity are prerequisites to realize the full potential of high‐material‐quality perovskite solar cells, first to maximize the internal voltage (or quasi‐Fermi‐level separation) iV within the absorber, then to translate this high internal voltage into a high external voltage V. Experimental quantification of contact passivation and selectivity is, thus, key to improving device performance. Here, open‐circuit measurements of iVoc and Voc, combined with surface photovoltage measurements, are used to systematically quantify the passivation—using iVoc as a metric—and the selectivity—defined as Soc = Voc/iVoc—of a range of common carrier transport layers to wide‐bandgap (1.67 eV) perovskite absorbers. The resulting solar cells suffer from large voltage deficits, particularly when NiOx is used as the hole transport layer, even though it provides better passivation than its polymer‐based counterparts (PTAA and PTAA/PFN). This indicates a poor selectivity of NiOx (Soc < 0.81 for NiOx‐based devices), whereas devices using polymer‐based hole transport layers exhibit high selectivity (Soc = 0.94–0.95). In agreement with recent reports, this low selectivity is attributed to the formation of an interlayer of non‐perovskite material with high resistance to holes at the perovskite/NiOx interface. These measurements also imply that the selectivity of the C60‐based electron transport layers is relatively good.
α‐Amylase Immobilization on P(HEMA‐co‐PEGMA) Hydrogels: Preparation, Characterization, and Catalytic Investigation
Authors: Doğan Demet , Ulu Ahmet , Sel Evren , Köytepe Süleyman , Ateş Burhan
Published: May 2021

The aims of this study are to synthesize and characterize poly (2‐hydroxyethyl methacrylate‐co‐poly (ethylene glycol) methacrylate) (P(HEMA‐co‐PEG500MA)) structures containing polyethylene glycol (PEG) side groups and to investigate their possible use in α‐amylase immobilization. For this purpose, P(HEMA‐co‐PEG500MA) copolymer structures are synthesized by using different monomer ratios. P(HEMA‐co‐PEG500MA) copolymer structures are confirmed by Fourier transform infrared spectroscopy (FTIR), and elemental analysis techniques. In addition, thermal, and morphological properties of the copolymers are investigated by thermal gravimetric analysis/differential scanning calorimetry, and scanning electron microscopy (SEM). Afterward, α‐amylase from Aspergillus oryzae is immobilized on synthesized copolymer support by using physical interactions. The success of immobilization is elucidated via FTIR, SEM, and energy dispersive X‐ray spectroscopy (EDX) methods. In addition, the influences of temperature, pH, storage time, and repeated uses on the activity of free and immobilized α‐amylase are investigated. According to the outcomes, the immobilized α‐amylase possesses a better pH and thermal resistance than the free one. Additionally, the immobilized α‐amylase maintains about 53% of its original activity after eight reuses and it exhibits about 50% relative activity after 28 days of storage. In conclusion, the immobilized α‐amylase can be utilized as a potential efficient catalyst to produce maltose from the hydrolysis of starch.
Characterization and Antibacterial Activity of Encapsulated Rosemary Essential Oil within Amylose Nanostructures as a Natural Antimicrobial in Food Applications
Authors: Amani Fateme , Sami Masoud , Rezaei Atefe
Published: May 2021

Rosemary essential oil (REO) is a natural phenolic compound with high antimicrobial activity. However, its application is limited due to the poor solubility in water, instability, and high volatility. In this study, REO is incorporated into the high amylose corn starch (HACS) nanostructures by inclusion complexation. The characterization of the obtained nanostructures is done by SEM, TGA, FTIR, and XRD. Encapsulation efficiency, loading capacity, stability, release, and antibacterial activity of encapsulated REO are analyzed. The nanostructures show spherical nanoparticles with an average size lower than 200 nm. The results of XRD and FTIR confirm the incorporation of REO into the amylose nanostructures. Thermogravimetric analysis indicates that the inclusion complex of REO and HACS increases the thermal stability of REO significantly. The solubility and antibacterial activity of REO are enhanced after complexation with amylose nanostructures. Minimum inhibitory concentration (MIC) of free REO is 3.52 mg mL−1 or 0.39% v/v and for encapsulated REO is decreased to 2.5 mg mL−1. The results suggest that HACS can be used as a potential carrier for sensitive and hydrophobic compounds to enhance their application in the pharmaceutical and food industries.
Systems Chemistry in Self‐Healing Materials
Authors: Li Panpan , Hao Jingcheng , Wang Xu
Published: May 2021

Self‐healing materials are a kind of intelligent materials that have the ability to repair themselves after damage. By using chemical reaction networks to temporarily control the dynamics of covalent or coordination bonds, systems chemistry has recently shown great promise to reconcile the contradiction between the kinetic stability/inertness and intrinsic healing ability of synthetic materials. When compared to the traditional self‐healing strategies for synthetic materials, the regulation of the healing ability of materials by systems chemistry looks clumsy, but it represents a way similar to the self‐healing in biological systems, which is essentially regulated by complex biochemical reaction networks. Therefore, this field is worthy of further studies. In this Minireview, the significance, achievements and expectations of systems chemistry in regulating the healing ability of synthetic materials are discussed. We hope that it would be an inspiration for creating smart self‐healing materials with life‐like properties.
Recent Development in the Synthesis and Catalytic Application of Iridacycles
Authors: Chen Zhenyu , Kacmaz Aysecik , Xiao Jianliang
Published: May 2021

Cyclometallated complexes are well‐known and have found many applications. This article provides a short review on the progress made in the synthesis and application to catalysis of cyclometallated half‐sandwich Cp*Ir(III) complexes (Cp*: pentamethylcyclopentadienyl) since 2017. Covered in the review are iridacycles featuring conventional C,N chelates and less common metallocene and carbene‐derived C,N and C,C ligands. This is followed by an overview of the studies of their applications in catalysis ranging from asymmetric hydrogenation, transfer hydrogenation, hydrosilylation to dehydrogenation.
Choosing the right exit: How functional plasticity of the nuclear pore drives selective and efficient mRNA export
Authors: Bensidoun Pierre , Zenklusen Daniel , Oeffinger Marlene
Published: May 2021

The nuclear pore complex (NPC) serves as a central gate for mRNAs to transit from the nucleus to the cytoplasm. The ability for mRNAs to get exported is linked to various upstream nuclear processes including co‐transcriptional RNP assembly and processing, and only export competent mRNPs are thought to get access to the NPC. While the nuclear pore is generally viewed as a monolithic structure that serves as a mediator of transport driven by transport receptors, more recent evidence suggests that the NPC might be more heterogenous than previously believed, both in its composition or in the selective treatment of cargo that seek access to the pore, providing functional plasticity to mRNA export. In this review, we consider the interconnected processes of nuclear mRNA metabolism that contribute and mediate export competence. Furthermore, we examine different aspects of NPC heterogeneity, including the role of the nuclear basket and its associated complexes in regulating selective and/or efficient binding to and transport through the pore.

This article is categorized under:

RNA Export and Localization > Nuclear Export/Import

RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms

RNA Interactions with Proteins and Other Molecules > Protein‐RNA Interactions: Functional Implications
Dyson’s classification and real division superalgebras
Authors: Geiko Roman , Moore Gregory W.
Published: May 2021

Abstract

It is well-known that unitary irreducible representations of groups can be usefully classified in a 3-fold classification scheme: Real, Complex, Quaternionic. In 1962 Freeman Dyson pointed out that there is an analogous 10-fold classification of irreducible representations of groups involving both unitary and antiunitary operators. More recently, it was realized that there is also a 10-fold classification scheme involving superdivision algebras. Here we give a careful proof of the equivalence of these two 10-fold ways.
Analysis of some heterogeneous catalysis models with fast sorption and fast surface chemistry
Authors: Augner Björn , Bothe Dieter
Published: May 2021

We investigate limit models resulting from a dimensional analysis of quite general heterogeneous catalysis models with fast sorption (i.e. exchange of mass between the bulk phase and the catalytic surface of a reactor) and fast surface chemistry for a prototypical chemical reactor. For the resulting reaction–diffusion systems with linear boundary conditions on the normal mass fluxes, but at the same time nonlinear boundary conditions on the concentrations itself, we provide analytic properties such as local-in-time well-posedness, positivity, a priori bounds and comment on steps towards global existence of strong solutions in the class$$\mathrm {W}^{(1,2)}_p(J \times \Omega ; {{\,\mathrm{{\mathbb {R}}}\,}}^N)$$Wp(1,2)(J×Ω;RN), and of classical solutions in the Hölder class$$\mathrm {C}^{(1+\alpha , 2 + 2\alpha )}({\overline{J}} \times {\overline{\Omega }}; {{\,\mathrm{{\mathbb {R}}}\,}}^N)$$C(1+α,2+2α)(J¯×Ω¯;RN). Exploiting that the model is based on thermodynamic principles, we further show a priori bounds related to mass conservation and the entropy principle.
Fetale Alkoholspektrumstörungen – Diagnose, Prognose und Prävention
Authors: Moder Judith E. , Ordenewitz Lisa K. , Schlüter Julia A. , Weinmann Tobias , Altebäumer Philine , Jung Jessica , Heinen Florian , Landgraf Mirjam N.
Published: May 2021

Die Fetale Alkoholspektrumstörung ist eine der häufigsten bei Geburt bestehenden chronischen Erkrankungen, die zum Großteil nicht oder fehldiagnostiziert wird. Dies führt zu inadäquater, ineffektiver Förderung und Therapie der erkrankten Kinder sowie mangelnder Unterstützung der betroffenen Familien. Daraus resultiert nicht nur ein hohes Maß an Sekundärerkrankungen, sondern auch eine Einbuße in der Möglichkeit der Sekundär- und Tertiärprävention bei erkrankten Kindern und betroffenen Familien. Sekundär und Tertiärprävention sind jedoch bei richtiger und rechtzeitiger Diagnose möglich. Die Primärprävention im Bereich Alkoholkonsum in der Schwangerschaft und Fetale Alkoholspektrumstörung muss auch in Zukunft sowohl von medizinischer als auch politischer Seite strukturiert, interdisziplinär und wissenschaftlich basiert geplant und durchgeführt werden. Neben der Aufklärung der Allgemeinbevölkerung ist hierbei die Wissensvermittlung an ÄrztInnen und andere medizinisch-psychologisch-pädagogische Fachkräfte besonders relevant.
Increasing longevity and life satisfaction: is there a catch to living longer?
Authors: Nemitz Janina
Published: May 2021

Human longevity is rising rapidly all over the world, but are longer lives more satisfied lives? This study suggests that the answer might be no. Despite a substantial increase in months of satisfying life, people’s overall life satisfaction declined between 1985 and 2011 in West Germany due to substantial losses of life satisfaction in old age. When compared to 1985, in 2011, elderly West Germans were, on average, much less satisfied throughout their last five years of life. Moreover, they spent a larger proportion of their remaining lifetime in states of dissatisfaction, on average. Two important mechanisms that contributed to this satisfaction decline were health and social isolation. Using a broad variety of sensitivity tests, I show that these results are robust to a large set of alternative explanations.
Mental health among clinicians: what do we know and what can we do?
Authors: Patel Mittal , Swift Steven , Digesu Alex
Published: May 2021

Mental health and mental health disorders among clinicians remain a taboo, despite increasing evidence showing the direct impact on medical teams and patient care. This editorial is aimed at increasing awareness of mental issues amongst healthcare professionals, identifying perceived barriers to seeking help, and suggesting ways in which to seek help. Mental health disorders, including anxiety and depression, are prevalent from medical school, leading to increased burnout and suicide risks at later stages of a clinician’s career. There is often a reluctance to seek help, particularly amongst the surgical specialties, caused by self-criticism, lack of convenient access and the potential negative impact on medical licensure. This editorial has been written in loving memory of our colleague, friend and board member Dr. Nikolaus Veit-Rubin, who sadly passed away at the beginning of the year. It is written in the hope of highlighting the importance of maintaining mental wellbeing amongst the medical team, supporting help-seeking behaviour and changing attitudes toward mental health disorders amongst clinicians.
Shapes of hyperbolic triangles and once-punctured torus groups
Authors: Kim Sang-hyun , Koberda Thomas , Lee Jaejeong , Ohshika Ken’ichi , Tan Ser Peow , Gao Xinghua
Published: May 2021

Let$$\Delta $$Δbe a hyperbolic triangle with a fixed area$$\varphi $$φ. We prove that for all but countably many$$\varphi $$φ, generic choices of$$\Delta $$Δhave the property that the group generated by the$$\pi $$π-rotations about the midpoints of the sides of the triangle admits no nontrivial relations. By contrast, we show for all$$\varphi \in (0,\pi ){\setminus }\mathbb {Q}\pi $$φ∈(0,π)\Qπ, a dense set of triangles does afford nontrivial relations, which in the generic case map to hyperbolic translations. To establish this fact, we study the deformation space$$\mathfrak {C}_\theta $$Cθof singular hyperbolic metrics on a torus with a single cone point of angle$$\theta =2(\pi -\varphi )$$θ=2(π-φ), and answer an analogous question for the holonomy map$$\rho _\xi $$ρξof such a hyperbolic structure$$\xi $$ξ. In an appendix by Gao, concrete examples of$$\theta $$θand$$\xi \in \mathfrak {C}_\theta $$ξ∈Cθare given where the image of each$$\rho _\xi $$ρξis finitely presented, non-free and torsion-free; in fact, those images will be isomorphic to the fundamental groups of closed hyperbolic 3-manifolds.
A comprehensive review of imaging findings in COVID-19 - status in early 2021
Authors: Afshar-Oromieh Ali , Prosch Helmut , Schaefer-Prokop Cornelia , Bohn Karl Peter , Alberts Ian , Mingels Clemens , Thurnher Majda , Cumming Paul , Shi Kuangyu , Peters Alan , Geleff Silvana , Lan Xiaoli , Wang Feng , Huber Adrian , Gräni Christoph , Heverhagen Johannes T. , Rominger Axel , Fontanellaz Matthias , Schöder Heiko , Christe Andreas , Mougiakakou Stavroula , Ebner Lukas
Published: May 2021

Medical imaging methods are assuming a greater role in the workup of patients with COVID-19, mainly in relation to the primary manifestation of pulmonary disease and the tissue distribution of the angiotensin-converting-enzyme 2 (ACE 2) receptor. However, the field is so new that no consensus view has emerged guiding clinical decisions to employ imaging procedures such as radiography, computer tomography (CT), positron emission tomography (PET), and magnetic resonance imaging, and in what measure the risk of exposure of staff to possible infection could be justified by the knowledge gained. The insensitivity of current RT-PCR methods for positive diagnosis is part of the rationale for resorting to imaging procedures. While CT is more sensitive than genetic testing in hospitalized patients, positive findings of ground glass opacities depend on the disease stage. There is sparse reporting on PET/CT with [18F]-FDG in COVID-19, but available results are congruent with the earlier literature on viral pneumonias. There is a high incidence of cerebral findings in COVID-19, and likewise evidence of gastrointestinal involvement. Artificial intelligence, notably machine learning is emerging as an effective method for diagnostic image analysis, with performance in the discriminative diagnosis of diagnosis of COVID-19 pneumonia comparable to that of human practitioners.
Airflow Limitation Predicts Postoperative Pneumonia after Esophagectomy
Authors: Maruyama Suguru , Okamura Akihiko , Ishizuka Naoki , Kanie Yasukazu , Sakamoto Kei , Fujiwara Daisuke , Kanamori Jun , Imamura Yu , Watanabe Masayuki
Published: May 2021

Background

Chronic obstructive pulmonary disease (COPD) is known to be a risk factor of pneumonia after esophagectomy. In this study, we investigated the relationship of airflow limitation with the occurrence and the severity of pneumonia in esophageal cancer patients who underwent esophagectomy.

Methods

We enrolled 844 patients who underwent curative esophagectomy between 2009 and 2018. The airflow limitation was evaluated using the percent‐predicted forced expiratory volume at 1 s (%FEV1) with spirometry.

Results

There were 597 (70.7%), 141 (16.7%), 68 (8.1%), and 38 patients (4.5%) with %FEV1 of ≥ 90%, 80–90%, 70–80%, and < 70% categories, respectively. One hundred and ninety‐one patients (22.6%) occurred pneumonia, and the incidences of pneumonia in each category of patients were 18.8%, 28.4%, 29.4%, and 50.0%, respectively. In multivariate analysis, the categories of 80%–90%, 70–80%, and < 70% were significantly associated with a higher incidence of postoperative pneumonia (OR 1.57; 95% CI 1.02–2.43, OR 1.87; 95% CI 1.04–3.36, OR 3.34; 95% CI 1.66–6.71, respectively), with the %FEV1 category of ≥ 90% as reference. The incidence of severe pneumonia of Clavien–Dindo grade III or higher was also significantly associated with the %FEV1. In patients without COPD, the incidence of pneumonia was significantly higher in those with %FEV1 < 90% than in those with %FEV1 ≥ 90% (32.2% versus 17.5%, p < 0.001).

Conclusions

The airflow limitation can help predict the occurrence of pneumonia after esophagectomy in patients with and without COPD. Exclusive preventive measures should be considered in patients with reduced %FEV1 undergoing esophagectomy.
Profiling of bacterial bloodstream infections in hematological and oncological patients based on a comparative survival analysis
Authors: Weber Sarah , Magh Aaron , Hogardt Michael , Kempf Volkhard A. J. , Vehreschild Maria J. G. T. , Serve Hubert , Scheich Sebastian , Steffen Björn
Published: May 2021

Bloodstream infections (BSI) are a frequent complication in patients with hematological and oncological diseases. However, the impact of different bacterial species causing BSI and of multiple BSI remains incompletely understood. We performed a retrospective study profiling 637 bacterial BSI episodes in hematological and oncological patients. Based on the 30-day (30d) overall survival (OS), we analyzed different types of multiple BSI and grouped BSI-associated bacteria into clusters followed by further assessment of clinical and infection-related characteristics. We discovered that polymicrobial BSI (different organisms on the first day of a BSI episode) and sequential BSI (another BSI before the respective BSI episode) were associated with a worse 30d OS. Different bacterial groups could be classified into three BSI outcome clusters based on 30d OS: favorable (FAV) including mainly common skin contaminants, Escherichia spp. and Streptococcus spp.; intermediate (INT) including mainly Enterococcus spp., vancomycin-resistant Enterococcus spp., and multidrug-resistant gram-negative bacteria (MDRGN); and adverse (ADV) including MDRGN with an additional carbapenem-resistance (MDRGN+CR). A polymicrobial or sequential BSI especially influenced the outcome in the combination of two INT cluster BSI. The presence of a polymicrobial BSI and the assignment into the BSI outcome clusters were identified as independent risk factors for 30d mortality in a Cox multivariate regression analysis. The assignment to a BSI outcome cluster and the differentiated perspective of multiple BSI open new insights into the prognosis of patients with BSI and should be further validated in other patient cohorts.
Correction to: Radiation dose and fluoroscopy time of modern endovascular treatment techniques in patients with saccular unruptured intracranial aneurysms
Authors: Forbrig Robert , Ozpeynirci Yigit , Grasser Matthias , Dorn Franziska , Liebig Thomas , Trumm Christoph G.
Published: May 2021

A Correction to this paper has been published: 10.1007/s00330-021-07874-1
Numerical and experimental study on turbulence statistics in a large fan-stirred combustion vessel
Authors: Morsy M. E. , Yang J.
Published: May 2021

Particle image velocimetry (PIV) has become a popular non-intrusive tool for measuring various types of flows. However, when measuring three-dimensional flows with two-dimensional (2D) PIV, there are some uncertainties in the measured velocity field due to out-of-plane motion, which might alter turbulence statistics and distort the overall flow characteristics. In the present study, three different turbulence models are employed and compared. Mean and fluctuating fields obtained by three-dimensional computational fluid dynamics modeling are compared to experimental data. Turbulence statistics such as integral length scale, Taylor microscale, Kolmogorov scale, turbulence kinetic energy, dissipation rate, and velocity correlations are calculated at different experimental conditions (i.e., pressure, temperature, fan speed, etc.). A reasonably isotropic and homogeneous turbulence with large turbulence intensities is achieved in the central region extending to almost 45 mm radius. This radius decreases with increasing the initial pressure. The influence of the third dimension velocity component on the measured characteristics is negligible. This is a result of the axisymmetric features of the flow pattern in the current vessel. The results prove that the present vessel can be conveniently adopted for several turbulent combustion studies including mainly the determination of turbulent burning velocity for gaseous premixed flames in nearly homogeneous isotropic turbulence.

Graphic abstract
Glucagon-like peptide-1 (GLP-1) receptor activation dilates cerebral arterioles, increases cerebral blood flow, and mediates remote (pre)conditioning neuroprotection against ischaemic stroke
Authors: Nizari Shereen , Basalay Marina , Chapman Philippa , Korte Nils , Korsak Alla , Christie Isabel N. , Theparambil Shefeeq M. , Davidson Sean M. , Reimann Frank , Trapp Stefan , Yellon Derek M. , Gourine Alexander V.
Published: May 2021

Stroke remains one of the most common causes of death and disability worldwide. Several preclinical studies demonstrated that the brain can be effectively protected against ischaemic stroke by two seemingly distinct treatments: remote ischaemic conditioning (RIC), involving cycles of ischaemia/reperfusion applied to a peripheral organ or tissue, or by systemic administration of glucagon-like-peptide-1 (GLP-1) receptor (GLP-1R) agonists. The mechanisms underlying RIC- and GLP-1-induced neuroprotection are not completely understood. In this study, we tested the hypothesis that GLP-1 mediates neuroprotection induced by RIC and investigated the effect of GLP-1R activation on cerebral blood vessels, as a potential mechanism of GLP-1-induced protection against ischaemic stroke. A rat model of ischaemic stroke (90 min of middle cerebral artery occlusion followed by 24-h reperfusion) was used. RIC was induced by 4 cycles of 5 min left hind limb ischaemia interleaved with 5-min reperfusion periods. RIC markedly (by ~ 80%) reduced the cerebral infarct size and improved the neurological score. The neuroprotection established by RIC was abolished by systemic blockade of GLP-1R with a specific antagonist Exendin(9–39). In the cerebral cortex of GLP-1R reporter mice, ~ 70% of cortical arterioles displayed GLP-1R expression. In acute brain slices of the rat cerebral cortex, activation of GLP-1R with an agonist Exendin-4 had a strong dilatory effect on cortical arterioles and effectively reversed arteriolar constrictions induced by metabolite lactate or oxygen and glucose deprivation, as an ex vivo model of ischaemic stroke. In anaesthetised rats, Exendin-4 induced lasting increases in brain tissue PO2, indicative of increased cerebral blood flow. These results demonstrate that neuroprotection against ischaemic stroke established by remote ischaemic conditioning is mediated by a mechanism involving GLP-1R signalling. Potent dilatory effect of GLP-1R activation on cortical arterioles suggests that the neuroprotection in this model is mediated via modulation of cerebral blood flow and improved brain perfusion.
A new non-aggregative splicing isoform of human Tau is decreased in Alzheimer’s disease
Authors: García-Escudero Vega , Ruiz-Gabarre Daniel , Gargini Ricardo , Pérez Mar , García Esther , Cuadros Raquel , Hernández Ivó H. , Cabrera Jorge R. , García-Escudero Ramón , Lucas José J. , Hernández Félix , Ávila Jesús
Published: May 2021

Tauopathies, including Alzheimer’s disease (AD) and frontotemporal lobar degeneration with Tau pathology (FTLD-tau), are a group of neurodegenerative disorders characterized by Tau hyperphosphorylation. Post-translational modifications of Tau such as phosphorylation and truncation have been demonstrated to be an essential step in the molecular pathogenesis of these tauopathies. In this work, we demonstrate the existence of a new, human-specific truncated form of Tau generated by intron 12 retention in human neuroblastoma cells and, to a higher extent, in human RNA brain samples, using qPCR and further confirming the results on a larger database of human RNA-seq samples. Diminished protein levels of this new Tau isoform are found by Westernblotting in Alzheimer’s patients’ brains (Braak I n = 3; Braak II n = 6, Braak III n = 3, Braak IV n = 1, and Braak V n = 10, Braak VI n = 8) with respect to non-demented control subjects (n = 9), suggesting that the lack of this truncated isoform may play an important role in the pathology. This new Tau isoform exhibits similar post-transcriptional modifications by phosphorylation and affinity for microtubule binding, but more interestingly, is less prone to aggregate than other Tau isoforms. Finally, we present evidence suggesting this new Tau isoform could be linked to the inhibition of GSK3β, which would mediate intron 12 retention by modulating the serine/arginine rich splicing factor 2 (SRSF2). Our results show the existence of an important new isoform of Tau and suggest that further research on this less aggregation-prone Tau may help to develop future therapies for Alzheimer’s disease and other tauopathies.
Incidence of and risk factors for vaginal cuff dehiscence following total laparoscopic hysterectomy: a monocentric hospital analysis
Authors: Radosa Julia Caroline , Radosa Marc Philipp , Zimmermann Julia Sarah Maria , Braun Eva-Marie , Findeklee Sebastian , Wieczorek Annette , Stotz Lisa , Hamza Amr , Takacs Ferenc Zoltan , Risius Uda Mareke , Gerlinger Christoph , Radosa Christoph Georg , Wagenpfeil Stefan , Solomayer Erich-Franz
Published: May 2021

Purpose

Vaginal cuff dehiscence (VCD) is one of the major surgical complications following hysterectomy with data on incidence rates varying largely and studies assessing risk factors being sparse with contradictive results. The aim of this study was to assess the incidence rate of and risk factors for VCD in a homogenous cohort of women treated for benign uterine pathologies via total laparoscopic hysterectomy (TLH) with standardized follow-up.

Methods

All patients undergoing TLH at the Department of Gynecology and Obstetrics, Saarland University Hospital between November 2010 and February 2019 were retrospectively identified from a prospectively maintained service database.

Results

VCD occurred in 18 (2.9%) of 617 patients included. In univariate and multivariate analyses, a lower level of surgeon laparoscopic expertise (odds ratio 3.19, 95% confidence interval (CI) 1.0–9.38; p = 0.03) and lower weight of removed uterus (odds ratio 0.99, 95% CI 0.98–0.99; p = 0.02) were associated positively with the risk of VCD.

Conclusion

In this homogenous cohort undergoing TLH, laparoscopic expertise and uterine weight influenced the risk of postoperative VCD. These findings might help to further reduce the rate of this complication.
The Role of Galectins in Chronic Lung Allograft Dysfunction
Authors: d’Alessandro Miriana , Bergantini Laura , Fossi Antonella , De Vita Elda , Perillo Felice , Luzzi Luca , Paladini Piero , Sestini Piersante , Rottoli Paola , Bargagli Elena , Bennett David
Published: May 2021

Background

Galectins are proteins that bind β-galactosides such as N-acetyllactosamine present in N-linked and O-linked glycoproteins and that seem to be implicated in inflammatory and immune responses as well as fibrotic mechanisms. This preliminary study investigated serum galectins as clinical biomarkers in lung transplant patients with chronic lung allograft dysfunction (CLAD), phenotype bronchiolitis obliterans syndrome (BOS).

Materials and Methods

Nineteen lung transplant patients [median age (IQR), 55 (45–62) years; 53% males] were enrolled in the study. Peripheral blood concentrations of galectins-1, 3 and 9 were determined with commercial ELISA kits.

Results

Galectin-1 concentrations were higher in BOS than in stable LTX patients (p = 0.0394). In logistic regression analysis, testing BOS group as dependent variable with Gal-1 and 3 as independent variables, area under the receiver operating characteristics (AUROC) curve was 98.9% (NPV 90% and PPV 88.9%, p = 0.0003). With the stable LTX group as dependent variable and Gal-1, 3 and 9 as independent variables, AUROC was 92.6% (NPV 100% and PPV 90%, p = 0.0023). In stable patients were observed an inverse correlation of Gal-3 with DLCO% and KCO%, and between Gal-9 and KCO%.

Conclusion

Galectins-1, 3 and 9 are possible clinical biomarkers in lung transplant patients with diagnostic and prognostic meaning. These molecules may be directly implicated in the pathological mechanisms of BOS. The hypothesis that they could be new therapeutic targets in BOS patients is intriguing and also worth exploring.
Targeted residual stress generation in single and two point incremental sheet forming (ISF)
Authors: Maqbool Fawad , Maaß Fabian , Buhl Johannes , Hahn Marlon , Hajavifard Ramin , Walther Frank , Tekkaya A. Erman , Bambach Markus
Published: May 2021

The mechanical properties and the operating life of a formed component are highly dependent on the residual stress state. There is always a high magnitude of residual stresses in the components formed by incremental sheet forming (ISF) due to the localized deformation mechanism. Hence, a thorough understanding of the generation of the residual stresses by ISF is necessary. This study investigates the residual stress generation mechanism for two process variants of ISF, i.e., Single Point Incremental Forming (SPIF) and Two Point Incremental Forming (TPIF). This understanding is used to control and targetedly generate the residual stresses to improve the part performance. In this regard, the residual stress state in a truncated cone geometry manufactured using SPIF and disc springs manufactured using TPIF was experimentally analyzed. Validated numerical models for both process variants were developed to study the residual stresses in detail. The residual stress state in SPIF is such that the tool contact side develops tensile residual stresses and the non-contact side undergoes compressive residual stresses. The tool step-down variation was used to control residual stresses and improve the fatigue strength of truncated cones manufactured using SPIF. For TPIF, two different forming strategies were used to analyze the residual stress generation mechanism and the role of major process parameters. The residual stresses for TPIF are pre-dominantly compressive in both directions of forming tool motion. For both process variants of the ISF process, it is shown that the residual stresses can be beneficially utilized to improve mechanical properties of the components.
A detailed characterization of the hyperpolarization-activated “funny” current (If) in human-induced pluripotent stem cell (iPSC)–derived cardiomyocytes with pacemaker activity
Authors: Giannetti Federica , Benzoni Patrizia , Campostrini Giulia , Milanesi Raffaella , Bucchi Annalisa , Baruscotti Mirko , Dell’Era Patrizia , Rossini Alessandra , Barbuti Andrea
Published: May 2021

Properties of the funny current (If) have been studied in several animal and cellular models, but so far little is known concerning its properties in human pacemaker cells. This work provides a detailed characterization of If in human-induced pluripotent stem cell (iPSC)–derived pacemaker cardiomyocytes (pCMs), at different time points. Patch-clamp analysis showed that If density did not change during differentiation; however, after day 30, it activates at more negative potential and with slower time constants. These changes are accompanied by a slowing in beating rate. If displayed the voltage-dependent block by caesium and reversed (Erev) at − 22 mV, compatibly with the 3:1 K+/Na+ permeability ratio. Lowering [Na+]o (30 mM) shifted the Erev to − 39 mV without affecting conductance. Increasing [K+]o (30 mM) shifted the Erev to − 15 mV with a fourfold increase in conductance. pCMs express mainly HCN4 and HCN1 together with the accessory subunits CAV3, KCR1, MiRP1, and SAP97 that contribute to the context-dependence of If. Autonomic agonists modulated the diastolic depolarization, and thus rate, of pCMs. The adrenergic agonist isoproterenol induced rate acceleration and a positive shift of If voltage-dependence (EC50 73.4 nM). The muscarinic agonists had opposite effects (Carbachol EC50, 11,6 nM). Carbachol effect was however small but it could be increased by pre-stimulation with isoproterenol, indicating low cAMP levels in pCMs. In conclusion, we demonstrated that pCMs display an If with the physiological properties expected by pacemaker cells and may thus represent a suitable model for studying human If-related sinus arrhythmias.
Quantitative fluorescence angiography aids novice and experienced surgeons in performing intestinal resection in well-perfused tissue
Authors: Nerup Nikolaj , Svendsen Morten Bo Søndergaard , Rønn Jonas Hedelund , Konge Lars , Svendsen Lars Bo , Achiam Michael Patrick
Published: May 2021

Background

Anastomotic leakage (AL) after gastrointestinal resection is a devastating complication with huge consequences for the patient. As AL is associated with poor blood supply, tools for objective assessment of perfusion are in high demand. Indocyanine green angiography (ICG-FA) and quantitative analysis of ICG-FA (q-ICG) seem promising. This study aimed to investigate whether ICG-FA and q-ICG could improve perfusion assessment performed by surgeons of different experience levels.

Methods

Thirteen small bowel segments with a varying degree of devascularization, including two healthy sham segments, were constructed in a porcine model. We recruited students, residents, and surgeons to perform perfusion assessment of the segments in white light (WL), with ICG-FA, and after q-ICG, all blinded to the degree of devascularization.

Results

Forty-five participants fulfilled the study (18 novices, 12 intermediates, and 15 experienced). ICG and q-ICG helped the novices correctly detect the healthy bowel segments to experienced surgeons’ level. ICG and q-ICG also helped novice surgeons to perform safer resections in healthy tissue compared with normal WL. The relative risk (RR) of leaving ischemic tissue in WL and ICG compared with q-ICG, even for experienced surgeons was substantial, intermediates (RR = 8.9, CI95% [4.0;20] and RR = 6.2, CI95% [2.7;14.1]), and experienced (RR = 4.7, CI95% [2.6;8.7] and RR = 4.0, CI95% [2.1;7.5]).

Conclusion

Q-ICG seems to guide surgeons, regardless of experience level, to safely perform resection in healthy tissue, compared with standard WL. Future research should focus on this novel tool’s clinical impact.