bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron‐Scale Measurements of Dipolarization Front
Authors: Liu C. M. , Fu H. S. , Xu Y. , Khotyaintsev Y. V. , Burch J. L. , Ergun R. E. , Gershman D. G. , Torbert R. B. 
Published: May 2018

AbstractDipolarization front (DF)—a sharp boundary with scale of ion inertial length (c/ωpi) in the Earth's magnetotail—can also have fine structures at electron scale (c/ωpe). Such electron‐scale structures, determining the local energy conversion, have not been revealed by multispacecraft observations so far, due to the large separation of spacecraft in previous studies. Here we report the first electron‐scale multispacecraft measurements of DF, using data from the recent Magnetospheric Multiscale mission. We find strong parallel currents only in the high‐density side of the DF but strong perpendicular currents across the whole DF. We find no parallel electric fields during the DF interval. Although DF is primarily an energy‐load region (E·J > 0), the electron‐scale currents could lead to a localized energy generation (E·J < 0). Such features are different from those reported in previous multispacecraft studies, where the currents, electric fields, and energy conversion are uniform across the DF; they also shed lights on the study of substorm current wedge, which is crucial in the magnetosphere‐ionosphere coupling.
Structural basis of actin monomer re-charging by cyclase-associated protein
Authors: Kotila Tommi , Kogan Konstantin , Enkavi Giray , Guo Siyang , Vattulainen Ilpo , Goode Bruce L. , Lappalainen Pekka 
Published: May 2018

AbstractActin polymerization powers key cellular processes, including motility, morphogenesis, and endocytosis. The actin turnover cycle depends critically on “re-charging” of ADP-actin monomers with ATP, but whether this reaction requires dedicated proteins in cells, and the underlying mechanism, have remained elusive. Here we report that nucleotide exchange catalyzed by the ubiquitous cytoskeletal regulator cyclase-associated protein (CAP) is critical for actin-based processes in vivo. We determine the structure of the CAP–actin complex, which reveals that nucleotide exchange occurs in a compact, sandwich-like complex formed between the dimeric actin-binding domain of CAP and two ADP-actin monomers. In the crystal structure, the C-terminal tail of CAP associates with the nucleotide-sensing region of actin, and this interaction is required for rapid re-charging of actin by both yeast and mammalian CAPs. These data uncover the conserved structural basis and biological role of protein-catalyzed re-charging of actin monomers.
Cyclin K regulates prereplicative complex assembly to promote mammalian cell proliferation
Authors: Lei Tingjun , Zhang Peixuan , Zhang Xudong , Xiao Xue , Zhang Jingli , Qiu Tong , Dai Qian , Zhang Yujun , Min Ling , Li Qian , Yin Rutie , Ding Ping , Li Ni , Qu Yi , Mu Dezhi , Qin Jun , Zhu Xiaofeng , Xiao Zhi-Xiong , Li Qintong 
Published: May 2018

AbstractThe assembly of prereplicative complex (pre-RC) during G1 phase must be tightly controlled to sustain cell proliferation and maintain genomic stability. Mechanisms to prevent pre-RC formation in G2/M and S phases are well appreciated, whereas how cells ensure efficient pre-RC assembly during G1 is less clear. Here we report that cyclin K regulates pre-RC formation. We find that cyclin K expression positively correlates with cell proliferation, and knockdown of cyclin K or its cognate kinase CDK12 prevents the assembly of pre-RC in G1 phase. Mechanistically we uncover that cyclin K promotes pre-RC assembly by restricting cyclin E1 activity in G1. We identify a cyclin K-dependent, novel phosphorylation site in cyclin E1 that disrupts its interaction with CDK2. Importantly, this antagonistic relationship is largely recapitulated in cyclin E1-overexpressing tumors. We discuss the implications of our findings in light of recent reports linking cyclin K and CDK12 to human tumorigenesis.
Frequent pauses in Escherichia coli flagella elongation revealed by single cell real-time fluorescence imaging
Authors: Zhao Ziyi , Zhao Yifan , Zhuang Xiang-Yu , Lo Wei-Chang , Baker Matthew A. B. , Lo Chien-Jung , Bai Fan 
Published: May 2018

AbstractThe bacterial flagellum is a large extracellular protein organelle that extrudes from the cell surface. The flagellar filament is assembled from tens of thousands of flagellin subunits that are exported through the flagellar type III secretion system. Here, we measure the growth of Escherichia coli flagella in real time and find that, although the growth rate displays large variations at similar lengths, it decays on average as flagella lengthen. By tracking single flagella, we show that the large variations in growth rate occur as a result of frequent pauses. Furthermore, different flagella on the same cell show variable growth rates with correlation. Our observations are consistent with an injection-diffusion model, and we propose that an insufficient cytoplasmic flagellin supply is responsible for the pauses in flagellar growth in E. coli.
Structural basis for the recognition of complex-type N-glycans by Endoglycosidase S
Authors: Trastoy Beatriz , Klontz Erik , Orwenyo Jared , Marina Alberto , Wang Lai-Xi , Sundberg Eric J. , Guerin Marcelo E. 
Published: May 2018

AbstractEndoglycosidase S (EndoS) is a bacterial endo-β-N-acetylglucosaminidase that specifically catalyzes the hydrolysis of the β-1,4 linkage between the first two N-acetylglucosamine residues of the biantennary complex-type N-linked glycans of IgG Fc regions. It is used for the chemoenzymatic synthesis of homogeneously glycosylated antibodies with improved therapeutic properties, but the molecular basis for its substrate specificity is unknown. Here, we report the crystal structure of the full-length EndoS in complex with its oligosaccharide G2 product. The glycoside hydrolase domain contains two well-defined asymmetric grooves that accommodate the complex-type N-linked glycan antennae near the active site. Several loops shape the glycan binding site, thereby governing the strict substrate specificity of EndoS. Comparing the arrangement of these loops within EndoS and related endoglycosidases, reveals distinct-binding site architectures that correlate with the respective glycan specificities, providing a basis for the bioengineering of endoglycosidases to tailor the chemoenzymatic synthesis of monoclonal antibodies.
Belief state representation in the dopamine system
Authors: Babayan Benedicte M. , Uchida Naoshige , Gershman Samuel. J. 
Published: May 2018

AbstractLearning to predict future outcomes is critical for driving appropriate behaviors. Reinforcement learning (RL) models have successfully accounted for such learning, relying on reward prediction errors (RPEs) signaled by midbrain dopamine neurons. It has been proposed that when sensory data provide only ambiguous information about which state an animal is in, it can predict reward based on a set of probabilities assigned to hypothetical states (called the belief state). Here we examine how dopamine RPEs and subsequent learning are regulated under state uncertainty. Mice are first trained in a task with two potential states defined by different reward amounts. During testing, intermediate-sized rewards are given in rare trials. Dopamine activity is a non-monotonic function of reward size, consistent with RL models operating on belief states. Furthermore, the magnitude of dopamine responses quantitatively predicts changes in behavior. These results establish the critical role of state inference in RL.
Simulated microgravity attenuates myogenic differentiation via epigenetic regulations
Authors: Furukawa Takuma , Tanimoto Keiji , Fukazawa Takahiro , Imura Takeshi , Kawahara Yumi , Yuge Louis 
Published: May 2018

AbstractThe molecular mechanisms involved in myogenic differentiation are relatively well-known. Myogenic differentiation is regulated by the sequential activation of the basic helix-loop-helix myogenic regulatory transcription factors (MRFs), and biomechanical signals play an important role in the regulation of myogenesis. In this study, we sought to determine whether simulated microgravity culture using Gravite® may affect myoblast differentiation and expression of MRF genes. Although rat myoblasts, L6 cells were differentiated to myotubes in an incubation period-dependent manner, myogenesis of L6 cells was significantly attenuated under simulated microgravity (10-3G) conditions. Real-time Reverse transcription polymerase chain reaction (RT-PCR) showed that expressions of Myog, Myf6, Mef2c, Des, and Ckm under 1 G conditions increase in an incubation period-dependent manner, and that Myod1 expression was specifically observed to increase transiently in the early phase. However, expressions of Myod1 and Myog were significantly inhibited under simulated microgravity conditions. To clarify the molecular mechanisms, L6 cells were treated with 5-AzaC, and further incubated with differentiation medium under 1 G or 10−3 G conditions. The results showed differences in expression levels of Myod1, Myog, and, as well as those of myotube thickness between 1 G and 10−3 G conditions, completely disappeared in this experimental condition. Modified HpaII tiny fragment enrichment by ligation-mediated PCR (HELP)-assay showed that kinetic changes of DNA methylation status were attenuated in simulated microgravity conditions. These results indicate that microgravity regulates myogenesis and Myod1 expression by controlling DNA methylation.
Robust quantum sensing with strongly interacting probe systems
Authors: Dooley Shane , Hanks Michael , Nakayama Shojun , Munro William J. , Nemoto Kae 
Published: May 2018

AbstractIn the field of quantum metrology and sensing, a collection of quantum systems (e.g., spins) are used as a probe to estimate some physical parameter (e.g., magnetic field). It is usually assumed that there are no interactions between the probe systems. We show that strong interactions between them can increase robustness against thermal noise, leading to enhanced sensitivity. In principle, the sensitivity can scale exponentially in the number of probes—even at non-zero temperatures—if there are long-range interactions. This scheme can also be combined with other techniques, such as dynamical decoupling, to give enhanced sensitivity in realistic experiments.
Automatic anatomical classification of esophagogastroduodenoscopy images using deep convolutional neural networks
Authors: Takiyama Hirotoshi , Ozawa Tsuyoshi , Ishihara Soichiro , Fujishiro Mitsuhiro , Shichijo Satoki , Nomura Shuhei , Miura Motoi , Tada Tomohiro 
Published: May 2018

AbstractThe use of convolutional neural networks (CNNs) has dramatically advanced our ability to recognize images with machine learning methods. We aimed to construct a CNN that could recognize the anatomical location of esophagogastroduodenoscopy (EGD) images in an appropriate manner. A CNN-based diagnostic program was constructed based on GoogLeNet architecture, and was trained with 27,335 EGD images that were categorized into four major anatomical locations (larynx, esophagus, stomach and duodenum) and three subsequent sub-classifications for stomach images (upper, middle, and lower regions). The performance of the CNN was evaluated in an independent validation set of 17,081 EGD images by drawing receiver operating characteristics (ROC) curves and calculating the area under the curves (AUCs). ROC curves showed high performance of the trained CNN to classify the anatomical location of EGD images with AUCs of 1.00 for larynx and esophagus images, and 0.99 for stomach and duodenum images. Furthermore, the trained CNN could recognize specific anatomical locations within the stomach, with AUCs of 0.99 for the upper, middle, and lower stomach. In conclusion, the trained CNN showed robust performance in its ability to recognize the anatomical location of EGD images, highlighting its significant potential for future application as a computer-aided EGD diagnostic system.
Silver nanoparticles promote the emergence of heterogeneic human neutrophil sub-populations
Authors: Fraser Jennifer A. , Kemp Sadie , Young Lesley , Ross Mark , Prach Morag , Hutchison Gary R. , Malone Eva 
Published: May 2018

AbstractNeutrophil surveillance is central to nanoparticle clearance. Silver nanoparticles (AgNP) have numerous uses, however conflicting evidence exists as to their impact on neutrophils and whether they trigger damaging inflammation. Neutrophil’s importance in innate defence and regulating immune networks mean it’s essential we understand AgNP’s impact on neutrophil function. Human neutrophil viability following AgNP or Ag Bulk treatment was analysed by flow cytometry and AnV/PI staining. Whilst AgNP exposure did not increase the total number of apoptotic neutrophils, the number of late apoptotic neutrophils was increased, suggesting AgNP increase transit through apoptosis. Mature (CD16bright/CD62Lbright), immature (CD16dim/CD62Lbright) and apoptotic (CD16dim/CD62Ldim) neutrophil populations were evident within isolated neutrophil preparations. AgNP exposure significantly reduced CD62L staining of CD16bright/CD62Lbrightneutrophils, and increased CD16 staining of CD16dim/CD62Lbrightpopulations, suggesting AgNPs trigger neutrophil activation and maturation, respectively. AgNP exposure dramatically increased IL-8, yet not classical pro-inflammatory cytokine release, suggesting AgNP triggers neutrophil activation, without pro-inflammation or damaging, necrotic cell death. For the first time, we show AgNPs differentially affect distinct sub-populations of circulating human neutrophils; activating mature neutrophils with the emergence of CD16bright/CD62Ldimneutrophils. This may stimulate particle clearance without harmful inflammation, challenging previous assumptions that silver nanomaterials induce neutrophil toxicity and damaging inflammatory responses.
Correlation between ultrasound-diagnosed non-alcoholic fatty liver and periodontal condition in a cross-sectional study in Japan
Authors: Iwasaki Takahiro , Hirose Akiko , Azuma Tetsuji , Ohashi Tamie , Watanabe Kazutoshi , Obora Akihiro , Deguchi Fumiko , Kojima Takao , Isozaki Atsunori , Tomofuji Takaaki 
Published: May 2018

AbstractThis cross-sectional study investigated the relationship between periodontal condition and ultrasound-diagnosed non-alcoholic fatty liver disease (NAFLD) in a Japanese oral health check population. A total of 1226 consecutive participant were enrolled in the study. Abdominal ultrasonography was applied to diagnose NAFLD. Of the study participants, 339 (27.7%) had ultrasonography-diagnosed NAFLD. The participants with NAFLD had a significantly higher prevalence of probing pocket depth (PPD) ≥ 4 mm (86.7%) than those without NAFLD (72.9%) (p < 0.05). After adjusting for gender, age, Brinkman index, regular exercise habits, body mass index, number of teeth present, presence of periodontitis, blood pressure, and serum parameters, there was a statistically significant difference in the adjusted odds ratios of having PPD ≥ 4 mm for NAFLD (Odds ratio = 1.881, 95% confidence interval 1.184–2.987, p < 0.01). Having PPD ≥ 4 mm may be a risk factor for ultrasound-diagnosed NAFLD in this cross-sectional study of a Japanese oral health check population.
Segregation mediated heterogeneous structure in a metastable β titanium alloy with a superior combination of strength and ductility
Authors: Gao Junheng , Nutter John , Liu Xingguang , Guan Dikai , Huang Yuhe , Dye David , Rainforth W. Mark 
Published: May 2018

AbstractIn β titanium alloys, the β stabilizers segregate easily and considerable effort has been devoted to alleviate/eliminate the segregation. In this work, instead of addressing the segregation problems, the segregation was utilized to develop a novel microstructure consisting of a nanometre-grained duplex (α+β) structure and micrometre scale β phase with superior mechanical properties. An as-cast Ti-9Mo-6W alloy exhibited segregation of Mo and W at the tens of micrometre scale. This was subjected to cold rolling and flash annealing at 820 oC for 2 and 5 mins. The solidification segregation of Mo and W leads to a locally different microstructure after cold rolling (i.e., nanostructured β phase in the regions rich in Mo and W and plate-like martensite and β phase in regions relatively poor in Mo and W), which play a decisive role in the formation of the heterogeneous microstructure. Tensile tests showed that this alloy exhibited a superior combination of high yield strength (692 MPa), high tensile strength (1115 MPa), high work hardening rate and large uniform elongation (33.5%). More importantly, the new technique proposed in this work could be potentially applicable to other alloy systems with segregation problems.
Diagnostic value of ultrasound features and sex of fetuses in female patients with papillary thyroid microcarcinoma
Authors: Hou Chun-jie , Wei Ran , Tang Jing-lan , Hu Qiao-hong , He Hong-feng , Fan Xiao-ming 
Published: May 2018

AbstractLittle work has been done on the prediction of papillary thyroid microcarcinoma in female patients who have given birth to children, which may be different from other people. We performed a retrospective review of female patients who underwent thyroidectomy, aiming at identifying special predictors of papillary thyroid microcarcinoma in female patients who have given birth to children. Univariate analysis was used to identify potential covariates for the prediction of papillary thyroid microcarcinoma. Multivariable logistic regression analysis was used to identify independent predictors and construct a regression model based on a training cohort (246 patients) and then the regression model was validated using an independent cohort (80 patients). We found that having not more than one boy, taller-than-wide shape, poorly defined margin, marked hypoechogenicity, and microcalcification were independent risk factors for the papillary thyroid microcarcinoma in multivariate analyses. The combined predictive formula had a high predictive effect for papillary thyroid microcarcinoma (AUC = 0.938 for training cohort and 0.929 for validation cohort, respectively). The combined predictive formula has clinical value in the prognosis of papillary thyroid microcarcinoma and it may be simple and effective to ask fertility condition of patients to increase the US diagnosis accuracy of papillary thyroid microcarcinoma.
Non-resonant Alfvénic instability activated by high temperature of ion beams in compensated-current astrophysical plasmas
Authors: Malovichko P. , Voitenko Y. , De Keyser J. 
Published: May 2018

Context. Compensated-current systems are established in response to hot ion beams in terrestrial foreshock regions, around supernova remnants, and in other space and astrophysical plasmas.
Aims. We study a non-resonant reactive instability of Alfvén waves propagating quasi-parallel to the background magnetic field B0 in such systems.
Methods. The instability is investigated analytically in the framework of kinetic theory applied to the hydrogen plasmas penetrated by hot proton beams.
Results. The instability arises at parallel wavenumbers kz that are sufficiently large to demagnetize the beam ions, kzVTb/ωBi ≳ 1 (here VTb is the beam thermal speed along B0 and ωBi is the ion-cyclotron frequency). The Alfvén mode is then made unstable by the imbalance of perturbed currents carried by the magnetized background electrons and partially demagnetized beam ions. The destabilizing effects of the beam temperature and the temperature dependence of the instability threshold and growth rate are demonstrated for the first time. The beam temperature, density, and bulk speed are all destabilizing and can be combined in a single destabilizing factor αb triggering the instability at αb > αbthr, where the threshold value varies in a narrow range 2.43 ≤ αbthr ≤ 4.87. New analytical expressions for the instability growth rate and its boundary in the parameter space are obtained and can be directly compared with observations. Two applications to terrestrial foreshocks and foreshocks around supernova remnants are briefly discussed. In particular, our results suggest that the ions reflected by the shocks around supernova remnants can drive stronger instability than the cosmic rays.
The root of a comet tail: Rosetta ion observations at comet 67P/Churyumov–Gerasimenko
Authors: Behar E. , Nilsson H. , Henri P. , Berčič L. , Nicolaou G. , Stenberg Wieser G. , Wieser M. , Tabone B. , Saillenfest M. , Goetz C. 
Published: May 2018

Context. The first 1000 km of the ion tail of comet 67P/Churyumov–Gerasimenko were explored by the European Rosetta spacecraft, 2.7 au away from the Sun.Aims. We characterised the dynamics of both the solar wind and the cometary ions on the night-side of the comet’s atmosphere.Methods. We analysed in situ ion and magnetic field measurements and compared the data to a semi-analytical model.Results. The cometary ions are observed flowing close to radially away from the nucleus during the entire excursion. The solar wind is deflected by its interaction with the new-born cometary ions. Two concentric regions appear, an inner region dominated by the expanding cometary ions and an outer region dominated by the solar wind particles.Conclusions. The single night-side excursion operated by Rosetta revealed that the near radial flow of the cometary ions can be explained by the combined action of three different electric field components, resulting from the ion motion, the electron pressure gradients, and the magnetic field draping. The observed solar wind deflection is governed mostly by the motional electric field −uion×B.
Difference in real-time magnetic image analysis of colonic looping patterns between males and females undergoing diagnostic colonoscopy
Authors: Lam Jacob , Wilkinson James , Brassett Cecilia , Brown Jonathan 
Published: May 2018

Abstract
Background and study aim Magnetic imaging technology is of proven benefit to trainees in colonoscopy, but few studies have examined its benefits in experienced hands. There is evidence that colonoscopy is more difficult in women. We set out to investigate (i) associations between the looping configurations in the proximal and distal colon and (ii) differences in the looping prevalence between the sexes. We have examined their significance in terms of segmental intubation times and position changes required for the completion of colonoscopy.
Patients and methods We analyzed 103 consecutive synchronized luminal and magnetic image videos of diagnostic colonoscopies with normal anatomy undertaken by a single experienced operator.
Results Deep transverse loops and sigmoid N-loops were more common in females. A deep transverse loop was more likely to be present if a sigmoid alpha-loop or N-loop had formed previously. Patients with sigmoid N-loops were turned more frequently from left lateral to supine before the sigmoid-descending junction was reached, but there was no statistical correlation between completion time and looping pattern.
Conclusions This study has reexamined the prevalence of the common looping patterns encountered during colonoscopy and has identified differences between the sexes. This finding may offer an explanation as to why colonoscopy has been shown to be more difficult in females. Although a deep transverse loop following a resolved sigmoid alpha-loop was the most commonly encountered pattern, no statistical correlation between completion time and looping pattern could be shown. It is the first study to examine segmental completion times using a magnetic imager in expert hands.