bluuebunny/crossref_metadata_2025 huggingface dataset:
A Bound on Ekman Pumping
Authors: de Roode Stephan R. , Siebesma A. Pier
Published: February 2020

Momentum transport by boundary layer turbulence causes a weak synoptic‐scale vertical motion. The classical textbook solution for the strength of this Ekman pumping depends on the curl of the surface momentum flux. A new solution for Ekman pumping is derived in terms of the curl of the geostrophic wind and a term that depends in a nontrivial way on the vertical profile of the turbulent momentum flux. The solution is confined to a boundary layer regime that is vertically well mixed and horizontally homogeneous. The momentum flux is computed from a commonly used bulk surface drag formula and a flux jump relation to capture the entrainment flux of momentum at the top of the boundary layer. It is found that the strength of Ekman pumping is bounded. The weakening of Ekman pumping for enhanced turbulent surface friction can be explained from the fact that it will reduce the magnitude of the horizontal wind. It is demonstrated that entrainment of momentum across the top of the boundary layer tends to diminish the large‐scale divergence of the wind. As momentum transport is parameterized in large‐scale models, the analysis is relevant for the understanding and interpretation of the evolution of synoptic‐scale vertical motions as predicted by such models.
A Network Approach for Delineating Homogeneous Regions in Regional Flood Frequency Analysis
Authors: Han Xudong , Ouarda Taha B. M. J. , Rahman Ataur , Haddad Khaled , Mehrotra Rajeshwar , Sharma Ashish
Published: February 2020

Regional flood frequency analysis forms the basis for ascertaining design thresholds for extreme flow events for the purpose of resource management and design of hydraulic structures, especially at ungauged or partially gauged basins. A crucial step in this analysis is transferring available information from gauged sites to ungauged sites, which is achieved through delineation of homogeneous regions encompassing multiple catchment locations, followed by the formulation of a flood estimation model. While this process has been accomplished through a range of statistical homogenization alternatives, the present study offers a new approach rooted in the theory of complex networks, offering considerable advantages over what is traditionally followed. Data from 202 sites in Australia representing catchments of varying geographic, climatic, and vegetation attributes are used to assess the alternative proposed. The results are examined via (1) direct comparison of the location and number of homogeneous neighbors from network theory with results using canonical correlation analysis (CCA) and (2) assessing the accuracy of estimated flood quantiles by applying a common model that estimates flood quantiles using information from the two alternate groups of homogeneous sites (from network theory and CCA). Results show that network theory offers merit in delineating homogenous regions, with resulting design flood estimates showing improvements across different return periods compared to the CCA alternative used.
[11C]PBR28 MR–PET imaging reveals lower regional brain expression of translocator protein (TSPO) in young adult males with autism spectrum disorder
Authors: Zürcher N. R. , Loggia M. L. , Mullett J. E. , Tseng C. , Bhanot A. , Richey L. , Hightower B. G. , Wu C. , Parmar A. J. , Butterfield R. I. , Dubois J. M. , Chonde D. B. , Izquierdo-Garcia D. , Wey H. Y. , Catana C. , Hadjikhani N. , McDougle C. J. , Hooker J. M.
Published: February 2020

Mechanisms of neuroimmune and mitochondrial dysfunction have been repeatedly implicated in autism spectrum disorder (ASD). To examine these mechanisms in ASD individuals, we measured the in vivo expression of the 18 kDa translocator protein (TSPO), an activated glial marker expressed on mitochondrial membranes. Participants underwent scanning on a simultaneous magnetic resonance–positron emission tomography (MR–PET) scanner with the second-generation TSPO radiotracer [11C]PBR28. By comparing TSPO in 15 young adult males with ASD with 18 age- and sex-matched controls, we showed that individuals with ASD exhibited lower regional TSPO expression in several brain regions, including the bilateral insular cortex, bilateral precuneus/posterior cingulate cortex, and bilateral temporal, angular, and supramarginal gyri, which have previously been implicated in autism in functional MR imaging studies. No brain region exhibited higher regional TSPO expression in the ASD group compared with the control group. A subset of participants underwent a second MR–PET scan after a median interscan interval of 3.6 months, and we determined that TSPO expression over this period of time was stable and replicable. Furthermore, voxelwise analysis confirmed lower regional TSPO expression in ASD at this later time point. Lower TSPO expression in ASD could reflect abnormalities in neuroimmune processes or mitochondrial dysfunction.
REEP5 depletion causes sarco-endoplasmic reticulum vacuolization and cardiac functional defects
Authors: Lee Shin-Haw , Hadipour-Lakmehsari Sina , Murthy Harsha R. , Gibb Natalie , Miyake Tetsuaki , Teng Allen C. T. , Cosme Jake , Yu Jessica C. , Moon Mark , Lim SangHyun , Wong Victoria , Liu Peter , Billia Filio , Fernandez-Gonzalez Rodrigo , Stagljar Igor , Sharma Parveen , Kislinger Thomas , Scott Ian C. , Gramolini Anthony O.
Published: February 2020

The sarco-endoplasmic reticulum (SR/ER) plays an important role in the development and progression of many heart diseases. However, many aspects of its structural organization remain largely unknown, particularly in cells with a highly differentiated SR/ER network. Here, we report a cardiac enriched, SR/ER membrane protein, REEP5 that is centrally involved in regulating SR/ER organization and cellular stress responses in cardiac myocytes. In vitro REEP5 depletion in mouse cardiac myocytes results in SR/ER membrane destabilization and luminal vacuolization along with decreased myocyte contractility and disrupted Ca2+ cycling. Further, in vivo CRISPR/Cas9-mediated REEP5 loss-of-function zebrafish mutants show sensitized cardiac dysfunction upon short-term verapamil treatment. Additionally, in vivo adeno-associated viral (AAV9)-induced REEP5 depletion in the mouse demonstrates cardiac dysfunction. These results demonstrate the critical role of REEP5 in SR/ER organization and function as well as normal heart function and development.
Immune checkpoint modulation enhances HIV-1 antibody induction
Authors: Bradley Todd , Kuraoka Masayuki , Yeh Chen-Hao , Tian Ming , Chen Huan , Cain Derek W. , Chen Xuejun , Cheng Cheng , Ellebedy Ali H. , Parks Robert , Barr Maggie , Sutherland Laura L. , Scearce Richard M. , Bowman Cindy M. , Bouton-Verville Hilary , Santra Sampa , Wiehe Kevin , Lewis Mark G. , Ogbe Ane , Borrow Persephone , Montefiori David , Bonsignori Mattia , Anthony Moody M. , Verkoczy Laurent , Saunders Kevin O. , Ahmed Rafi , Mascola John R. , Kelsoe Garnett , Alt Frederick W. , Haynes Barton F.
Published: February 2020

Eliciting protective titers of HIV-1 broadly neutralizing antibodies (bnAbs) is a goal of HIV-1 vaccine development, but current vaccine strategies have yet to induce bnAbs in humans. Many bnAbs isolated from HIV-1-infected individuals are encoded by immunoglobulin gene rearrangments with infrequent naive B cell precursors and with unusual genetic features that may be subject to host regulatory control. Here, we administer antibodies targeting immune cell regulatory receptors CTLA-4, PD-1 or OX40 along with HIV envelope (Env) vaccines to rhesus macaques and bnAb immunoglobulin knock-in (KI) mice expressing diverse precursors of CD4 binding site HIV-1 bnAbs. CTLA-4 blockade augments HIV-1 Env antibody responses in macaques, and in a bnAb-precursor mouse model, CTLA-4 blocking or OX40 agonist antibodies increase germinal center B and T follicular helper cells and plasma neutralizing antibodies. Thus, modulation of CTLA-4 or OX40 immune checkpoints during vaccination can promote germinal center activity and enhance HIV-1 Env antibody responses.
Successive redox-mediated visible-light ferrophotovoltaics
Authors: Noguchi Yuji , Taniguchi Yuki , Inoue Ryotaro , Miyayama Masaru
Published: February 2020

Titanium oxide materials have multiple functions such as photocatalytic and photovoltaic effects. Ferroelectrics provide access to light energy conversion that delivers above-bandgap voltages arising from spatial inversion symmetry breaking, whereas their wide bandgap leads to poor absorption of visible light. Bandgap narrowing offers a potential solution, but this material modification suppresses spontaneous polarization and, hence, sacrifices photovoltages. Here, we report successive-redox mediated ferrophotovoltaics that exhibit a robust visible-light response. Our single-crystal experiments and ab initio calculations, along with photo-luminescence analysis, demonstrate that divalent Fe2+ and trivalent Fe3+ coexisted in a prototypical ferroelectric barium titanate BaTiO3 introduce donor and acceptor levels, respectively, and that two sequential Fe3+/Fe2+ redox reactions enhance the photogenerated power not only under visible light but also at photon energies greater than the bandgap. Our approach opens a promising route to the visible-light activation of photovoltaics and, potentially, of photocatalysts.
Organocatalytic asymmetric N-sulfonyl amide C-N bond activation to access axially chiral biaryl amino acids
Authors: Wang Guanjie , Shi Qianqian , Hu Wanyao , Chen Tao , Guo Yingying , Hu Zhouli , Gong Minghua , Guo Jingcheng , Wei Donghui , Fu Zhenqian , Huang Wei
Published: February 2020

Amides are among the most fundamental functional groups and essential structural units, widely used in chemistry, biochemistry and material science. Amide synthesis and transformations is a topic of continuous interest in organic chemistry. However, direct catalytic asymmetric activation of amide C-N bonds still remains a long-standing challenge due to high stability of amide linkages. Herein, we describe an organocatalytic asymmetric amide C-N bonds cleavage of N-sulfonyl biaryl lactams under mild conditions, developing a general and practical method for atroposelective construction of axially chiral biaryl amino acids. A structurally diverse set of axially chiral biaryl amino acids are obtained in high yields with excellent enantioselectivities. Moreover, a variety of axially chiral unsymmetrical biaryl organocatalysts are efficiently constructed from the resulting axially chiral biaryl amino acids by our present strategy, and show competitive outcomes in asymmetric reactions.
The spatio-temporal features of chicken mitochondrial ND2 gene heteroplasmy and the effects of nutrition factors on this gene
Authors: Yang Suliang , Huo Yangyang , Wang Huanjie , Ji Jiefei , Chen Wen , Huang Yanqun
Published: February 2020

Mitochondrial heterogeneity is the presence of two or more types of mitochondrial (mt)DNA in the same individual/tissue/cell. It is closely related to animal health and disease. ND2 is a protein-coding gene in mtDNA, which participates in mitochondrial respiratory chain and oxidative phosphorylation. In previous studies, we observed that the mt.A5703T and mt.T5727G sites in the ND2 gene were the heteroplasmic variation sites. We used pyrophosphate sequencing technology to examine chicken mt.A5703T and mt.T5727G heteroplasmic sites in the ND2 gene, in different tissues and at different development stages in chickens. We also investigated whether nutritional factors could affect the mt.A5703T and mt.T5727G heteroplasmy. Our results showed that chicken mt.A5703T and mt.T5727G heteroplasmy had clear spatio-temporal specificities, which varied between tissues/development stages. The mtDNA heterogeneity was relatively stable upon nutrition intervention, 30% dietary energy restriction (from 18 to 48 days old) and different types of dietary fats (at 5% concentration, from 1 to 42 days old) did not change the breast muscle heteroplasmy of broilers at the mt.A5703T and mt.T5727G sites. In addition, multiple potential heteroplasmic sites were detected by clone sequencing in the ND2 region, which potentially reflected abundant heteroplasmy in the chicken mitochondrial genome. These results provide an important reference for further research on heteroplasmy in chicken mitochondria.
Immunohistochemical selection of biomarkers for tumor-targeted image-guided surgery of myxofibrosarcoma
Authors: de Gooyer Jan Marie , Versleijen-Jonkers Yvonne M. H. , Hillebrandt-Roeffen Melissa H. S. , Frielink Cathelijne , Desar Ingrid M. E. , de Wilt Johannes H. W. , Flucke Uta , Rijpkema Mark
Published: February 2020

Myxofibrosarcoma(MFS) is the most common soft tissue sarcoma(STS) in elderly patients. Surgical resection remains the main treatment modality but tumor borders can be difficult to delineate with conventional clinical methods. Incomplete resections are a common problem and local recurrence remains a clinical issue. A technique that has shown great potential in improving surgical treatment of solid tumors is tumor targeted imaging and image-guided surgery with near-infrared fluorescence. To facilitate this technique, it is essential to identify a biomarker that is highly and homogenously expressed on tumor cells, while being absent on healthy non-malignant tissue. The purpose of this study was to identify suitable molecular targets for tumor-targeted imaging of myxofibrosarcoma. Ten potential molecular targets for tumor targeted imaging were investigated with immunohistochemical analysis in myxofibrosarcoma tissue (n = 34). Results were quantified according to the immunoreactive score(IRS). Moderate expression rates were found for uPAR, PDGFRa and EMA/MUC1. High expression rates of VEGF and TEM1 were seen. Strong expression was most common for TEM1 (88.2%). These results confirms that TEM1 is a suitable target for tumor-targeted imaging of myxofibrosarcoma. Keywords Image-guided surgery; Immunohistochemistry; Molecular imaging; Myxofibrosarcoma; Soft tissue sarcoma; Tumor endothelial marker 1(TEM1), Vascular endothelial growth factor (VEGF).
Lead palladium titanate: A room temperature nanoscale multiferroic thin film
Authors: Mishra K. K. , Instan Alvaro A. , Kumari Shalini , Scott J. F. , Katiyar Ram S.
Published: February 2020

The discovery of single-phase multiferroic materials and the understanding of coupling mechanisms between their spin and polarization is important from the point of view of next generation logic and memory devices. Herein we report the fabrication, dielectric, ferroelectric, piezo-response force microscopy, and magnetization measurements of Pd-substituted room-temperature magnetoelectric multiferroic PbPd0.3Ti0.7O3 (PbPdT) thin films. Highly oriented PbPdT thin films were deposited on {(LaAlO3)0.3(Sr2AlTaO6)0.7} (LSAT) substrates in oxygen atmosphere using pulsed laser deposition technique. X-ray diffraction studies revealed that the films had tetragonal phase with (001) orientation. Surface morphology studies using atomic force and scanning electron microscopy suggest a smooth and homogeneous distribution of grains on the film surface with roughness ~2 nm. A large dielectric constant of ~1700 and a low-loss tangent value of ~0.3 at 10 kHz were obtained at room temperature. Temperature dependent dielectric measurements carried out on Pt/PbPdT/La0.7Sr0.3MnO3 (LSMO) metal-dielectric-metal capacitors suggest a ferroelectric to paraelectric transition above 670 K. The measured polarization hysteresis loops at room temperature were attributed to its ferroelectric behavior. From a Tauc plot of (αhν)2 versus energy, the direct band gap Eg of PbPdT thin films was calculated as 3 eV. Ferroelectric piezoelectric nature of the films was confirmed from a strong domain switching response revealed from piezo-response force microscopy. A well-saturated magnetization M-H loop with remanent magnetization of 3.5 emu/cm3 was observed at room temperature, and it retains ferromagnetic ordering in the temperature range 5–395 K. Origin of the magnetization could be traced to the mixed oxidation states of Pd2+/Pd4+ dispersed in polar PbTiO3 matrix, as revealed by our x-ray photoelectron spectroscopic results. These results suggest that PbPdT thin films are multiferroic (ferroelectric-ferromagnetic) at room temperature.
Identification, isolation, structural characterisation, synthesis and in silico toxicity prediction of the alkaline hydrolytic degradation product of brivaracetam by using LC-PDA, preparative HPLC, LC/HESI/LTQ, FTIR, and 1H NMR
Authors: Bhamare Pankaj , Umadoss P. , Upmanyu Neeraj , Dubey Rupal
Published: February 2020

Brivaracetam is a racetam derivative of levetiracetam with very limited data available on its degradation behaviour.
Novel inorganic aromatic mixed-valent superalkali electride CaN3Ca: an alkaline-earth-based high-sensitivity multi-state nonlinear optical molecular switch
Authors: Wang Yin-Feng , Qin Tian , Tang Jia-Min , Liu Yan-Jiao , Xie Miao , Li Jia , Huang Jiangen , Li Zhi-Ru
Published: February 2020

Focusing on innovative high-performance single-pole double-throw nonlinear optical (NLO) molecular switches, two C3v configurations (1 and 3) and one D3h configuration (2) of bipyramidal CaN3Ca have been obtained by using quantum mechanical methods.
Supramolecular design in 2D covalent organic frameworks
Authors: Alahakoon Sampath B. , Diwakara Shashini D. , Thompson Christina M. , Smaldone Ronald A.
Published: February 2020

2D covalent organic frameworks (COFs) are a class of porous polymers with crystalline structures. This tutorial review discusses how the concepts of supramolecular chemistry are used to add form and function to COFs through their non-covalent bonds.
Photoprotection of maqui berry against ultraviolet B-induced photodamage in vitro and in vivo
Authors: Chen Ling , Zhou Gao , Meng Xiao-Shan , Fu Hui-Ying , Mo Qi-Gui , Wang You-Wei
Published: February 2020

Maqui berry extracts could ameliorate oxidative stress, cellular DNA damage, and inflammation induced by UVB-irradiation in vitro and in vivo.
Acid-catalyzed pyrolytic synthesis of levoglucosan through salt-mediated ring locking
Authors: Chen Li , Elias Welman C. , Ben Yin Y. , Conrad Zhang Z. , Wong Michael S.
Published: February 2020

The combination of Na2SO4/H2SO4increases levoglucosan (LGA) yield from glucose pyrolysis from 6% to as high as 40%, as a result of sodium suppressing the opening of the glucose ring.
The preparation of hollow Fe3O4/Pd@C NCs to stabilize subminiature Pd nanoparticles for the reduction of 4-nitrophenol
Authors: Wang Congcong , Chen Yixin , Feng Siyang , Zhang Nan , Shen Lin , Zhang Kai , Yang Bai
Published: February 2020

Hollow Fe3O4/Pd@C NCs to stabilize subminiature Pd nanoparticles and exhibit excellent performance in the reduction of 4-NP.
Function of well-established mesoporous layers of recrystallized ZSM-22 zeolites in the catalytic performance ofn-alkane isomerization
Authors: Liu Suyao , Zhang Ling , Zhang Liwei , Zhang Huaike , Ren Jie
Published: February 2020

The effect of mesoporous layers of recrystallized ZSM-22/MCM-41 material on isomerization performance was systemically investigated using several probe molecules.
Direct analysis of Na, K, Mg and Ca in human saliva and correlations with physiological conditions
Authors: dos Reis Felipe Dias , Pereira Júnior Olavo dos Santos , de Sousa Rafael Arromba
Published: February 2020

An environmentally friendly method was developed for direct analysis of human saliva, allowing correlation of metal levels with physiological conditions.
Structural, thermodynamic, electronic and elastic properties of Th1−xUxO2 and Th1−xPuxO2 mixed oxides
Authors: Ghosh P. S. , Arya A.
Published: February 2020

The structural, thermodynamic, electronic, and elastic properties of Th1−xUxO2 and Th1−xPuxO2 mixed oxides (MOX) have been calculated with Hubbard corrected density functional theory (DFT+U) to account for the strong 5f electron correlations.
Field-induced slow magnetic relaxation in low-spin S = 1/2 mononuclear osmium(v) complexes
Authors: Su Qian-Qian , Fan Kun , Huang Xin-Da , Xiang Jing , Cheng Shun-Cheung , Ko Chi-Chiu , Zheng Li-Min , Kurmoo Mohamedally , Lau Tai-Chu
Published: February 2020

Stable low-spin Os(v) complexes obtained from the photochemical reactions of NO2-OsN showing slow magnetic relaxation behavior.
Dual attention module and multi‐label based fully convolutional network for crowd counting
Authors: Wang Suyu , Yang Bin , Liu Bo , Zheng Guanghui
Published: February 2020

High‐density crowd counting in natural scenes is an extremely difficult and challenging research subject in computer vision. Although the algorithm based on the convolutional neural network has achieved significantly better results than the traditional algorithm, most of them tend to focus on the local features of images, and difficult to obtain the rich global contextual dependencies. To solve this problem, a dual attention module and a multi‐label based fully convolutional network are proposed in this study. Moreover, the authors improve the algorithm by the following multiple perspectives. Firstly, introducing the dual attention module, the global‐context and long‐range dependency are adaptively integrated into both spatial and channel dimensions, which improve the network expression ability. Then, the prediction error is effectively reduced by designing a multi‐label mechanism, so the crowd‐counting task is transformed into foreground and background segmentation tasks to assist in the regression task of the density map. Furthermore, on the basis of the traditional Euclidean distance loss and cross‐entropy loss, the structural similarity index is introduced to further improve the training effect of the model. The test results of the UCF_CC_50, ShanghaiTech, and UCF‐QNRF datasets indicate that the proposed method is superior to the current mainstream algorithm.
First report on fatty acids composition, total phenolics and antioxidant activity in seeds oil of four fig cultivars (Ficus carica L.) grown in Morocco
Authors: Hssaini Lahcen , Hanine Hafida , Charafi Jamal , Razouk Rachid , Elantari Abderraouf , Ennahli Said , Hernández Francisca , Ouaabou Rachida
Published: February 2020

With the progresses of oilseed industry, an important interest is currently being focused on exploiting novel and underutilized sources for vegetable oils. Being so far the less studied part in fig fruits, seeds separated from four fig cultivars were assessed for their oil content, fatty acids identification, total phenolics and invitro antioxidant analysis. A one-way Anova yielded statistically significant differences for all parameters, with the exception of pentadecylic, margaric and arachidic acids besides the total saturated fatty acids. Fig seeds presented a yellow colored oil, of which the content ranged from 21.54 ± 1.71 to 28.52 ± 0.62%. Gas liquid chromatography analysis of the seed oil showed high percentages of linolenic acid in the four cultivars ranging from 38.43 ± 0.01 to 43.57 ± 0.04, followed by linoleic acid (28.9 ± 0.06–34.5 ± 0.04%). Palmitic acid and stearic acid were the dominating saturated fatty acids in all samples, where the amounts were in the range from 8.54 ± 0.04 to 9.05 ± 0.06% and from 2.59 ± 0.13 to 3.3% respectively. The efficiency of the desaturation from oleic acid to linoleic acid estimated within desaturation pathway, was higher among all cultivars than the efficiency of the desaturation from linoleic acid to linolenic acid. This explains the large increase of 18:3 concentration in all samples. The local cultivar ‘C11A21’ exhibited the highest total unsaturated fatty acids and the lowest level of saturated fatty acids, while the cultivar ‘White Adriatic’ combined the most relevant phenolics content, antioxidant activity and half maximum inhibitory concentration. All sampled oil possessed an important phenolics content that displayed variable levels of antioxidant activity. The objective of this study is to bring new data on the biochemical attributes of fig seeds as a new source oil that can be used for nutritional, pharmaceutical and cosmetic purposes.
Psychokardiologie bei koronaren Herzerkrankungen
Authors: Peregrinova Ludmila , Hamann Bettina
Published: February 2020

Die Psychokardiologie befasst sich mit den bidirektionalen Zusammenhängen zwischen Herzerkrankungen und psychischen Störungen. Privater und beruflicher Stress, psychische Erkrankungen sowie Persönlichkeitseigenschaften können das gesundheitliche Risikoverhalten begünstigen und folglich den Verlauf von kardiovaskulären Erkrankungen negativ beeinflussen. Hingegen lösen akute kardiale Ereignisse und chronische Herzerkrankungen häufig eine behandlungsbedürftige psychische Symptomatik aus, die die Krankheitsbewältigung beeinträchtigt und die Mortalität erhöht. Die ungünstigen psychosozialen Risikokonstellationen sollten somit identifiziert und behandelt werden, um langfristig positives Gesundheitsverhalten sowie die Lebensqualität der Patienten zu fördern und aufrechtzuerhalten.
Ozontherapie bei der Koronaren Herzerkrankung
Authors: Dorstewitz Hartmut
Published: February 2020

Die Ozon-Sauerstoff-Therapie kann in der Therapie der Koronaren Herzerkrankung im Rahmen eines komplementärmedizinischen Behandlungskonzepts einen wertvollen Beitrag leisten. Studien zur KHK mit Ozontherapie fehlen bislang, kleinere Studien u. a. zur peripheren arteriellen Verschlusskrankheit konnten positive Effekte untermauern. Die Ozontherapie ist deswegen bei KHK indiziert, weil diese Erkrankung, ganz ähnlich wie die periphere arterielle Verschlusskrankheit, ein vaskuläres Problem darstellt. Dabei spielt die Endothelfunktion eine entscheidende Rolle. Der antiinflammatorische Effekt durch Ozon-Sauerstoff-Therapie reduziert deutlich den oxidativen Stress und vermindert so die Endothelschädigung.

Die Ozontherapie erfolgt in der Praxis in Form der Großen Eigenbluttherapie oder seltener als Rektalinsufflation. Ein Fall aus der Praxis zeigt beispielhaft das Vorgehen und die möglichen Behandlungserfolge.
Study of secondary instability of precursor magnetic island in COMPASS density limit disruptions
Authors: Salzedas F. , Shah S. I. W. , Havlicek J. , Stöckel J. , Háček P. , Varju J. , Havránek A. , Pánek R. , Silva C.
Published: February 2020

A systematic study of COMPASS density limit disruptions (DLDs) was carried out to analyze the relation between the precursor magnetic island and its secondary instability (SI). In all of these plasmas, the SI was always found present at the onset of energy confinement erosion. The duration of this erosion was shorter for precursor quasi-locked island than for rotating island, and the larger the island amplitude, the shorter the duration. It was also found, at the onset of the erosion of energy confinement, an inverse relation between the magnetic island amplitude and its rotation frequency, showing that erosion can start at different values of precursor island amplitude, depending on what is its rotation frequency. DLDs occur either with smaller precursor island rotating faster or larger island rotating slower (quasi-locked).
Uncertainty propagation in complex networks: From noisy links to critical properties
Authors: Arola-Fernández Lluís , Mosquera-Doñate Guillem , Steinegger Benjamin , Arenas Alex
Published: February 2020

Many complex networks are built up from empirical data prone to experimental error. Thus, the determination of the specific weights of the links is a noisy measure. Noise propagates to those macroscopic variables researchers are interested in, such as the critical threshold for synchronization of coupled oscillators or for the spreading of a disease. Here, we apply error propagation to estimate the macroscopic uncertainty in the critical threshold for some dynamical processes in networks with noisy links. We obtain closed form expressions for the mean and standard deviation of the critical threshold depending on the properties of the noise and the moments of the degree distribution of the network. The analysis provides confidence intervals for critical predictions when dealing with uncertain measurements or intrinsic fluctuations in empirical networked systems. Furthermore, our results unveil a nonmonotonous behavior of the uncertainty of the critical threshold that depends on the specific network structure.
Candidates for p-type doping of ZnGeN2
Authors: Skachkov Dmitry , Lambrecht Walter R. L.
Published: February 2020

Various candidates for p-type doping in ZnGeN2 are considered and computationally studied using first-principles calculations. First, a brief update is made on our previous work about self-doping by deviations from stoichiometry, in the form of ZnGe, and Ga doping, GaGe. Both of these are hindered by competing donors in the form of GeZn and GaZn. We also consider Al instead of Ga doping. Cu would form an acceptor on both Zn and Ge sites. We determine the site-preference and consider also interstitial Cui. We find that CuZn, which is the preferred site, has a too deep level in the gap above the valence band maximum to be a useful p-type dopant. For C, we consider the CN acceptor as well as competing sites, inert CGe, and the Ci donor. We find that Ci forms a split-interstitial configuration and CGe is energetically close to CN, but the main conclusion is that the latter has a deep acceptor level unsuitable for p-type doping. Finally, we consider alkali metal doping. The LiGa defect is found to have the most favorable acceptor level position among the defects studied here, but it will suffer from possible compensation by Lii. Na and K are found to give deeper levels.
Phonon-induced near-field resonances in multiferroic BiFeO3 thin films at infrared and THz wavelengths
Authors: Wehmeier Lukas , Nörenberg Tobias , de Oliveira Thales V. A. G. , Klopf J. Michael , Yang Seung-Yeul , Martin Lane W. , Ramesh Ramamoorthy , Eng Lukas M. , Kehr Susanne C.
Published: February 2020

Multiferroic BiFeO3 (BFO) shows several phonon modes at infrared (IR) to THz energies, which are expected to carry information on any sample property coupled to crystal lattice vibrations. While macroscopic IR studies of BFO are often limited by single-crystal size, scattering-type scanning near-field optical microscopy (s-SNOM) allows for IR thin film spectroscopy of nanoscopic probing volumes with negligible direct substrate contribution to the optical signal. In fact, polaritons such as phonon polaritons of BFO introduce a resonant tip–sample coupling in s-SNOM, leading to both stronger signals and enhanced sensitivity to local material properties. Here, we explore the near-field response of BFO thin films at three consecutive resonances (centered around 5 THz, 13 THz, and 16 THz), by combining s-SNOM with a free-electron laser. We study the dependence of these near-field resonances on both the wavelength and tip–sample distance. Enabled by the broad spectral range of the measurement, we probe phonon modes connected to the predominant motion of either the bismuth or oxygen ions. Therefore, we propose s-SNOM at multiple near-field resonances as a versatile and very sensitive tool for the simultaneous investigation of various sample properties.
Enhanced multipactor statistical modeling for accurate threshold prediction with numerically tracking electron trajectories
Authors: Lin Shu , Sun Peng , Li Yongdong , Wang Hongguang , Liu Chunliang
Published: February 2020

Multipactor statistical modeling is one vital theoretical treatment for both multipactor mechanism analysis and threshold prediction, but its practical application is still severely constrained due to its obstinate dependence on the electron trajectory formula. Hence, this paper proposes a novel and general implementation method to improve the feasibility and accuracy of one-dimensional (1D) multipactor statistical modeling, where the joint probability density function is constructed through numerically tracking electron trajectories. On that basis, better agreement with the experimental results is obtained for multipactor threshold predictions of coaxial lines than the classical statistical calculations adopting the approximate electron trajectory formula. Besides the accuracy improvement, this approach also makes multipactor statistical modeling regardless of the field complexity and thus applicable to investigating any one-dimensional multipactor problem in microwave devices. This research work can further popularize the application of multipactor statistical modeling and provide one highly sought treatment with both good accuracy and efficiency for the optimal design of multipactor-free microwave devices, thus further promoting the development of space communication capability.
Starting behaviors of the TM-mode gyrotrons
Authors: Yao Hsin-Yu , Chen Chih-Chieh , Chang Tsun-Hsu
Published: February 2020

This work shows the derivations and calculations of the starting behaviors using the Laplace method and the numerical method. Calculated results based on these two methods agree well when dealing with a uniform structure, while the numerical method is advantageous for the non-uniform and practical structure. The applicability of the zero-field and the outgoing-wave boundary conditions at the collector end is discussed. These two boundary conditions agree well when the beam-wave resonant line and the waveguide dispersion curve intercept at the backward-wave region but differ significantly at the forward-wave region. The beam-wave coupling strength of the TM-mode gyrotron is found to be strongly correlated with the starting current, which can be utilized to avoid the potential competition from the transverse electric (TE) modes. The starting current of the TM11 gyrotron exhibits an additional operating condition at the low-beam voltage that may facilitate the development of low-cost and tabletop gyrotron systems. The beam-voltage and magnetic-field tunings are investigated for an open-cavity structure with the numerical method. Interestingly, the TM11 gyrotron as well as the TE01 gyrotron exhibits a similar starting behavior, which warrants the potential applications of the TM-mode gyrotrons.
Reversible oxidation and reduction of gold-supported iron oxide islands at room temperature
Authors: Jiang Yixuan , Zhu Yaguang , Zhou Dechun , Jiang Zhao , Si Nan , Stacchiola Dario , Niu Tianchao
Published: February 2020

Monolayer iron oxides grown on metal substrates have widely been used as model systems in heterogeneous catalysis. By means of ambient-pressure scanning tunneling microscopy (AP-STM), we studied the in situ oxidation and reduction of FeO(111) grown on Au(111) by oxygen (O2) and carbon monoxide (CO), respectively. Oxygen dislocation lines present on FeO islands are highly active for O2 dissociation. X-ray photoelectron spectroscopy measurements distinctly reveal the reversible oxidation and reduction of FeO islands after sequential exposure to O2 and CO. Our AP-STM results show that excess O atoms can be further incorporated on dislocation lines and react with CO, whereas the CO is not strong enough to reduce the FeO supported on Au(111) that is essential to retain the activity of oxygen dislocation lines.
Enhanced energy storage properties in Ba0.85Ca0.15Zr0.1Ti0.9O3 ceramics with glass additives
Authors: Wang X. W. , Zhang B. H. , Shi Y. C. , Li Y. Y. , Manikandan M. , Shang S. Y. , Shang J. , Hu Y. C. , Yin S. Q.
Published: February 2020

The Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics added with Bi2O3–B2O3–SiO2 glass were synthesized by the sol-gel method, and the effect on their microstructural, dielectric, energy storage properties has been discussed. The SEM results demonstrate that the average grain size decreases obviously with reducing glass additive, which is enriched at the grain boundary. Owing to the addition of glass additive, sintering temperature decreases significantly. Moreover, the glass additives broaden the dielectric peak and the Curie temperature shifts toward lower temperature. The ceramic with glass additive shows better impedance properties than that of pure BCZT ceramics. In addition, the coercive field and remnant polarization of hysteresis loop were greatly decreased by introducing glass additives in BCZT ceramics. Notably, the sample with 5% glass additive shows the highest energy storage density (2.12 J/cm3) and the largest storage efficiency (90.5%) at 330 kV/cm electric field. These findings provide a potential pathway to enhance energy storage properties of BCZT ceramics in order to promote its energy storage application in practice.
Detection of single DNA mismatches by force spectroscopy in short DNA hairpins
Authors: Landuzzi F. , Viader-Godoy X. , Cleri F. , Pastor I. , Ritort F.
Published: February 2020

Identification of defective DNA structures is a difficult task, since small differences in base-pair bonding are hidden in the local structural variability of a generally random base-pair sequence. Defects, such as base mismatches, missing bases, crosslinks, and so on, occur in DNA with high frequency and must be efficiently identified and repaired to avoid dire consequences such as genetic mutations. Here, we focus on the detection of base mismatches, which is local deviations from the ideal Watson–Crick pairing rule, which may typically originate from DNA replication process, foreign chemical attack, or ionizing radiation. Experimental detection of a mismatch defect demands the ability to measure slight deviations in the free energy and molecular structure. We introduce different mismatches in short DNA hairpins (10 or 20 base pairs plus a 4-base loop) sandwiched between dsDNA handles to be used in single-molecule force spectroscopy with optical tweezers. We perform both hopping and force-pulling experiments to measure the excess free energies and deduce the characteristic kinetic signatures of the mismatch from the force–distance curves. All-atom molecular dynamics simulations lend support to the detailed interpretation of the experimental data. Such measurements, at the lowest sensitivity limits of this experimental technique, demonstrate the capability of identifying the presence of mismatches in a random complementary dsDNA sequence and provide lower bounds for the ability to distinguish different structural defects.
Model for disordered proteins with strongly sequence-dependent liquid phase behavior
Authors: Statt Antonia , Casademunt Helena , Brangwynne Clifford P. , Panagiotopoulos Athanassios Z.
Published: February 2020

Phase separation of intrinsically disordered proteins is important for the formation of membraneless organelles or biomolecular condensates, which play key roles in the regulation of biochemical processes within cells. In this work, we investigated the phase separation of different sequences of a coarse-grained model for intrinsically disordered proteins and discovered a surprisingly rich phase behavior. We studied both the fraction of total hydrophobic parts and the distribution of hydrophobic parts. Not surprisingly, sequences with larger hydrophobic fractions showed conventional liquid–liquid phase separation. The location of the critical point was systematically influenced by the terminal beads of the sequence due to changes in interfacial composition and tension. For sequences with lower hydrophobicity, we observed not only conventional liquid–liquid phase separation but also re-entrant phase behavior in which the liquid phase density decreases at lower temperatures. For some sequences, we observed the formation of open phases consisting of aggregates, rather than a normal liquid. These aggregates had overall lower densities than the conventional liquid phases and exhibited complex geometries with large interconnected string-like or membrane-like clusters. Our findings suggest that minor alterations in the ordering of residues may lead to large changes in the phase behavior of the protein, a fact of significant potential relevance for biology.
Equation of state of the free electron gas in a magnetic field at arbitrary degeneracy
Authors: Faussurier Gérald
Published: February 2020

We study the equation of state of the non-relativistic free-electron gas in a constant magnetic field at arbitrary degeneracy based on the seminal work of Biswas et al. [Phys. Plasmas 20, 052503 (2013)]. The approach naturally unifies the Pauli paramagnetism, the Landau diamagnetism, and the de Haas–van Alphen effect. We consider the magnetization and the susceptibility as well as various thermodynamic quantities. In particular, the specific heats at constant volume and constant pressure are calculated, from which the adiabatic index is obtained. Weak and strong field limits are examined in detail. It is shown that the various quantities of interest saturate at strong magnetic field. Results are consistent with previous calculations performed at zero magnetic field. The polylogarithms are more adapted than the Fermi–Dirac integrals to describe the present system. The de Haas–van Alphen effect is not restricted to the magnetization and susceptibility but can be seen for other thermodynamic quantities.
MCSCF optimization revisited. II. Combined first- and second-order orbital optimization for large molecules
Authors: Kreplin David A. , Knowles Peter J. , Werner Hans-Joachim
Published: February 2020

A new orbital optimization for the multiconfiguration self-consistent field method is presented. This method combines a second-order (SO) algorithm for the optimization of the active orbitals with the first-order super configuration interaction (SCI) optimization of the remaining closed-virtual rotations and is denoted as the SO–SCI method. The SO–SCI method significantly improves the convergence as compared to the conventional SCI method. In combination with density fitting, the intermediates from the gradient calculation can be reused to evaluate the two-electron integrals required for the active Hessian without introducing a large computational overhead. The orbitals and CI coefficients are optimized alternately, but the CI-orbital coupling is accounted for by the limited memory Broyden–Fletcher–Goldfarb–Shanno quasi-Newton method. This further improves the speed of convergence. The method is applicable to large molecules. The efficiency and robustness of the presented method is demonstrated in benchmark calculations for 21 aromatic molecules as well as for various transition metal complexes with up to 826 electrons and 5154 basis functions.
Radial deformation and disintegration of an electrified liquid jet
Authors: Li Fang , Ke Shiyou , Xu Shumin , Yin Xieyuan , Yin Xiezhen
Published: February 2020

Droplets stretched by electric stresses emit jets from their pointed tips. We observed in the experiment a new tip-streaming phenomenon by applying a radial electric field to a liquid jet. Droplets in the jet are stretched in the radial direction and develop into a disk-like shape. The growth of non-axisymmetric harmonics leads to the formation of tens of Taylor cones evenly distributed at the equator of a droplet. At the tip of each cone, a tiny secondary jet is emitted, which breaks up into progeny droplets orders of magnitude smaller than the parent ones. This tip-streaming pattern may provide a new spraying route to the generation of micro- and nanosized droplets.
Switchable optical and acoustic resolution photoacoustic dermoscope dedicated into in vivo biopsy-like of human skin
Authors: Ma Haigang , Cheng Zhongwen , Wang Zhiyang , Zhang Wuyu , Yang Sihua
Published: February 2020

As a promising branch of optical absorption-based photoacoustic microscopy, photoacoustic dermoscopy (PAD) can provide manifold morphologic and functional information in clinical diagnosis and the assessment of dermatological conditions. However, most PAD setups are insufficient for clinical dermatology, given their single optical resolution (OR) or acoustic resolution (AR) mode, which results in poor spatiotemporal resolution or imaging depth for visualizing the internal texture of skin. Here, a switchable optical and acoustic resolution photoacoustic dermoscope (S-OR-ARPAD) system is developed, which provides a smooth transition from OR mode in microscopic imaging of superficial skin layers to AR mode when imaging at greater depths within intensely scattering deep skin layers. The lateral resolution can be seamlessly switched between 4.4 and 47 μm as the maximum imaging depth is switched between 1.2 and 1.8 mm for skin imaging. Using the S-OR-ARPAD, we identified the two distinct resolution modes responsible for resolving features of different skin layers and demonstrated the fine structures with strong contrast in the stratum corneum, dermal papillae, and microvascular structures in the horizontal plexus by imaging the healthy human skin at different locations.
Interference of electrical double layers: Confinement effects on structure, dynamics, and screening of ionic liquids
Authors: Park Suehyun , McDaniel Jesse G.
Published: February 2020

Ionic liquids are widely used as electrolytes in electronic devices in which they are subject to nanoconfinement within nanopores or nanofilms. Because the intrinsic width of an electrical double layer is on the order of several nanometers, nanoconfinement is expected to fundamentally alter the double layer properties. Furthermore, in confined systems, a large portion of the ions are interfacial, e.g., at the electrode interface, leading to significant deviations of electrostatic screening and ion dynamics as compared to bulk properties. In this work, we systematically investigate the interference between electrical double layers for nanoconfined ionic liquids and the resulting influence on the structure, dynamics, and screening behavior. We perform molecular dynamics simulations for the ionic liquids [BMIm+][BF4−] and [BMIm+][PF6−] confined between two flat electrodes at systematic separation distances between 1.5 nm and 4.5 nm for both conducting and insulating boundary conditions. We find that while ion dynamics is expectedly slower than in the bulk (by ∼2 orders of magnitude), there is an unexpected non-linear trend with the confinement length that leads to a local maximum in dynamic rates at ∼3.5–4.5 nm confinement. We show that this nonlinear trend is due to the ion correlation that arises from the interference between opposite double layers. We further evaluate confinement effects on the ion structure and capacitance and investigate the influence of electronic polarization of the ionic liquid on the resulting properties. This systematic evaluation of the connection between electrostatic screening and structure and dynamics of ionic liquids in confined systems is important for the fundamental understanding of electrochemical supercapacitors.