bluuebunny/crossref_metadata_2025_split huggingface dataset:
pH-dependent stability of honey bee (Apis mellifera) major royal jelly proteins
Authors: Mureşan Carmen I. , Buttstedt Anja 
Published: June 2019

AbstractHoney bee larval food jelly is a secretion of the hypopharyngeal and mandibular glands of young worker bees that take care of the growing brood in the hive. Food jelly is fed to all larvae (workers, drones and queens) and as royal jelly to the queen bee for her entire life. Up to 18% of the food jelly account for proteins the majority of which belongs to the major royal jelly protein (MRJP) family. These proteins are produced in the hypopharyngeal glands at a pH value of 7.0. Before being fed to the larvae, they are mixed with the fatty acids secreted by the mandibular glands of the worker bees resulting at a pH of 4.0 in the food jelly. Thus, MRJPs are exposed to a broad pH range from their site of synthesis to the actual secreted larval food. We therefore determined the pH-dependent stability of MRJP1, MRJP2 and MRJP3 purified from royal jelly using differential scanning fluorimetry. All MRJPs were much more stable at acidic pH values compared to neutral ones with all proteins showing highest stability at pH 4.0 or 4.5, the native pH of royal jelly.
Deriving and validating biomarkers associated with autism spectrum disorders from a large-scale resting-state database
Authors: Chen Chia-Min , Yang Pinchen , Wu Ming-Ting , Chuang Tzu-Chao , Huang Teng-Yi 
Published: June 2019

AbstractResting-state functional magnetic resonance imaging (MRI) has been used to investigate the brain activity related to autism spectrum disorder (ASD). In this study, we applied information from a large-scale dataset, the Autism Brain Imaging Data Exchange (ABIDE), to clinical applications. We recruited 21 patients with ASD and 23 individuals with neurotypical development (TD). We applied ASD biomarkers derived from ABIDE datasets and subsequently investigated the relationship between the MRI biomarkers and indicators from clinical screening questionnaires, the social responsiveness scale (SRS), and the Swanson, Nolan, and Pelham Questionnaire IV. The results indicated that the biomarkers generated from the default mode and executive control networks significantly differed between the participants with ASD and TD. In particular, the biomarkers derived from the default mode network were negatively correlated with the raw scores and model factors of the SRS. In summary, this study transferred the efforts of the global autism research community to clinical applications and identified connectivity-based biomarkers in ASD.
YB-1 recruitment to stress granules in zebrafish cells reveals a differential adaptive response to stress
Authors: Guarino Andrea Maria , Mauro Giuseppe Di , Ruggiero Gennaro , Geyer Nathalie , Delicato Antonella , Foulkes Nicholas S. , Vallone Daniela , Calabrò Viola 
Published: June 2019

AbstractThe survival of cells exposed to adverse environmental conditions entails various alterations in cellular function including major changes in the transcriptome as well as a radical reprogramming of protein translation. While in mammals this process has been extensively studied, stress responses in non-mammalian vertebrates remain poorly understood. One of the key cellular responses to many different types of stressors is the transient generation of structures called stress granules (SGs). These represent cytoplasmic foci where untranslated mRNAs are sorted or processed for re-initiation, degradation, or packaging into mRNPs. Here, using the evolutionarily conserved Y-box binding protein 1 (YB-1) and G3BP1 as markers, we have studied the formation of stress granules in zebrafish (D. rerio) in response to different environmental stressors. We show that following heat shock, zebrafish cells, like mammalian cells, form stress granules which contain both YB-1 and G3BP1 proteins. Moreover, zfYB-1 knockdown compromises cell viability, as well as recruitment of G3BP1 into SGs, under heat shock conditions highlighting the essential role played by YB-1 in SG assembly and cell survival. However, zebrafish PAC2 cells do not assemble YB-1-positive stress granules upon oxidative stress induced by arsenite, copper or hydrogen peroxide treatment. This contrasts with the situation in human cells where SG formation is robustly induced by exposure to oxidative stressors. Thus, our findings point to fundamental differences in the mechanisms whereby mammalian and zebrafish cells respond to oxidative stress.
Topology Effects on Sparse Control of Complex Networks with Laplacian Dynamics
Authors: Constantino Pedro H. , Tang Wentao , Daoutidis Prodromos 
Published: June 2019

AbstractEase of control of complex networks has been assessed extensively in terms of structural controllability and observability, and minimum control energy criteria. Here we adopt a sparsity-promoting feedback control framework for undirected networks with Laplacian dynamics and distinct topological features. The control objective considered is to minimize the effect of disturbance signals, magnitude of control signals and cost of feedback channels. We show that depending on the cost of feedback channels, different complex network structures become the least expensive option to control. Specifically, increased cost of feedback channels favors organized topological complexity such as modularity and centralization. Thus, although sparse and heterogeneous undirected networks may require larger numbers of actuators and sensors for structural controllability, networks with Laplacian dynamics are shown to be easier to control when accounting for the cost of feedback channels.
Endothelial cells promote 3D invasion of GBM by IL-8-dependent induction of cancer stem cell properties
Authors: McCoy Michael G. , Nyanyo Dennis , Hung Carol K. , Goerger Julian Palacios , R. Zipfel Warren , Williams Rebecca M. , Nishimura Nozomi , Fischbach Claudia 
Published: June 2019

AbstractRapid growth and perivascular invasion are hallmarks of glioblastoma (GBM) that have been attributed to the presence of cancer stem-like cells (CSCs) and their association with the perivascular niche. However, the mechanisms by which the perivascular niche regulates GBM invasion and CSCs remain poorly understood due in part to a lack of relevant model systems. To simulate perivascular niche conditions and analyze consequential changes of GBM growth and invasion, patient-derived GBM spheroids were co-cultured with brain endothelial cells (ECs) in microfabricated collagen gels. Integrating these systems with 3D imaging and biochemical assays revealed that ECs increase GBM invasiveness and growth through interleukin-8 (IL-8)-mediated enrichment of CSCs. Blockade of IL-8 inhibited these effects in GBM-EC co-cultures, while IL-8 supplementation increased CSC-mediated growth and invasion in GBM-monocultures. Experiments in mice confirmed that ECs and IL-8 stimulate intracranial tumor growth and invasion in vivo. Collectively, perivascular niche conditions promote GBM growth and invasion by increasing CSC frequency, and IL-8 may be explored clinically to inhibit these interactions.
1 billion-year-old cell contents preserved in monazite and xenotime
Authors: Wacey David , Sirantoine Eva , Saunders Martin , Strother Paul 
Published: June 2019

AbstractExceptional microfossil preservation, whereby sub-cellular details of an organism are conserved, remains extremely rare in the Precambrian rock record. We here report the first occurrence of exceptional cellular preservation by the rare earth element (REE) phosphates monazite and xenotime. This occurs in ~1 billion-year-old lake sediments where REEs were likely concentrated by local erosion and drainage into a closed lacustrine basin. Monazite and xenotime preferentially occur inside planktonic cells where they preserve spheroidal masses of plasmolyzed cell contents, and occasionally also membranous fragments. They have not been observed associated with cell walls or sheaths, which are instead preserved by clay minerals or francolite. REE phosphates are interpreted to be the earliest minerals precipitated in these cells after death, with their loci controlled by the micro-scale availability of inorganic phosphate (Pi) and REEs, probably sourced from polyphosphate granules within the cells. The strong affinity of REEs for phosphate and the insolubility of these minerals once formed means that REE phosphates have the potential for rapid preservation of cellular morphology after death and durability in the rock record. Hence, authigenic REE phosphates provide a promising new target in the search for the preservation of intra-cellular components of fossilised microorganisms.
Relationship between serum uric acid and hypertension: a cross-sectional study in Bangladeshi adults
Authors: Ali Nurshad , Mahmood Shakil , Islam Farjana , Rahman Shahnaz , Haque Tangigul , Islam Shiful , Rahman Sadaqur , Haque Nazmul , Mosaib Golam , Perveen Rasheda , Khanum Farida Adib 
Published: June 2019

AbstractExperimental evidence suggests a causal role of serum uric acid (SUA) in hypertension development. Currently, there are few data available on the association between SUA and hypertension; data from Bangladeshi adults are not available yet. This study evaluated the association of SUA with hypertension among Bangladeshi adults. Blood samples were obtained from 140 males and 115 females and analyzed for SUA and lipid levels. Hypertension was defined as SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg. All participants were divided into four quartiles based on SUA concentrations. Association of SUA with hypertension was evaluated by logistic regression models. The prevalence of hypertension and prehypertension was significantly higher in male (15.4 and 47.6%, respectively) than in the female (5.6 and 33.4%, respectively) subjects (p < 0.01). Males had a higher mean level of SUA (310.7 ± 67.9 µmol/L) than in the females (255.3 ± 69.3 µmol/L) (p < 0.001). Hyperuricemia was prevalent 9.1% in males and 10.3% in females. An increasing trend for hypertension and prehypertension was found in both genders with increasing SUA levels in the quartiles (p < 0.01). SUA levels in the quartiles were positively correlated with blood pressure (p < 0.01). After adjusting for baseline covariates, SUA levels were significantly associated with hypertension (p < 0.01). Findings of this study indicate the significance of maintaining normal SUA level to prevent hypertension.
Quantum reflection above the classical radiation-reaction barrier in the quantum electro-dynamics regime
Authors: Geng X. S. , Ji L. L. , Shen B. F. , Feng B. , Guo Z. , Yu Q. , Zhang L. G. , Xu Z. Z. 
Published: June 2019

AbstractHigh brightness gamma rays can be generated by colliding an ultra-intense laser pulse with a high energy electron beam. This collision phenomenon also represents a powerful approach to explore new physics in the exotic strong field Quantum Electro-Dynamics (QED) regime. Here we show that in the cross-collision geometry, there exists a barrier induced by the classical radiation-reaction force that prohibits electrons of arbitrarily high energies to pass. However, such classical barrier vanishes in the QED picture, where electrons can be well reflected (transmitted) in the regimes forbidden by classical theory. This effect can be measured in the up-coming 10–100 PW laser facilities for laser intensities at 2 × 1023 W cm−2 and electron energies of ~102 MeV. The results are capable of identifying the boundaries between classical and QED approaches in the strong field regime and confirming the various models describing this fundamental process.
Ovarian cancer-derived exosomes promote tumour metastasisin vivo: an effect modulated by the invasiveness capacity of their originating cells
Authors: Alharbi Mona , Lai Andrew , Guanzon Dominic , Palma Carlos , Zuñiga Felipe , Perrin Lewis , He Yaowu , Hooper John D. , Salomon Carlos 
Published: June 2019

AbstractExosomes are small nanovesicles that carry bioactive molecules which can be delivered to neighbouring cells to modify their biological functions. Studies have showed that exosomes from ovarian cancer (OVCA) cells can alter the cell migration and proliferation of cells within the tumour microenvironment, an effect modulated by the invasiveness capacity of their originating cells. Using an OVCA cell line xenograph mouse model, we showed that exosomes derived from a high invasiveness capacity cell line (exo-SKOV-3) promoted metastasis in vivo compared with exosomes from a low invasiveness capacity cell line (exo-OVCAR-3). Analysis from anin vivo imaging system (IVIS) revealed that exo-SKOV-3 formed metastatic niches, whereas exo-OVCAR-3 formed colonies of clustered cells close to the site of injection. Interestingly, kinetic parameters showed that the half-maximal stimulatory time (ST50) of tumour growth with exo-OVCAR-3 (4.0 ± 0.31 weeks) was significantly lower compared with the ST50 in mice injected with exo-SKOV-3 (4.5 ± 0.32 weeks). However, the number of metastic nodes in mice injected with exo-SKOV-3 was higher compared with exo-OVCAR-3. Using a quantitative mass spectrometry approach (SWATH MS/MS) followed by bioinformatics analysis using the Ingenuity Pathway Analysis (IPA), we identified a total of 771 proteins. Furthermore, 40 of these proteins were differentially expressed in tumour tissues from mice injected with exo-SKOV-3 compared with exo-OVCAR-3, and associated with Wnt canonical pathway (β-catenin). Finally, we identified a set of proteins which had elevated expression in the circulating exosomes in association with tumour metastasis. These observations suggest that exosomal signalling plays an important role in OVCA metastasis.
Titanium‐based nanoscale cross‐linker for guar gum fracturing fluid: effects on rheological behaviour and proppant‐carrying ability
Authors: Wang Chunnan , Zhang Zifeng , Du Jing , Li Xiaohong , Zhao Mengyun , Zhang Zhijun 
Published: June 2019

Ti4+ was introduced onto the surface of 3‐aminopropyltriethoxysilane (denoted as APTS; a silane coupling agent; commercial name: KH550) by surface‐modification technology to afford a precursor of nanoscale cross‐linker. The as‐obtained precursor of nanoscale cross‐linker was further transformed to a Ti‐based nanoscale cross‐linker (denoted as Ti‐NC) by hydrolysis and condensation in association with self‐aggregation. The microstructure of the Ti‐NC crosslinking guar gum gel was characterised by field emission scanning electron microscopy. Moreover, the effects of the as‐prepared Ti‐NC on the thermal stability, rheological behaviour, and proppant‐carrying ability of guar gum fracturing fluid were investigated with boric acid and TiCl4 as the controls. Results indicate that the as‐prepared Ti‐NC has a sphere‐like shape and a size of 6–13 nm. In the meantime, the guar gum gel cross‐linked by Ti‐NC exhibits better thermal stability, rheological behaviour, and proppant‐carrying ability than the ones cross‐linked by TiCl4 or boric acid, which indicates that the as‐prepared Ti‐NC could find promising application in enhancing the oil recovery of the low‐permeability reservoir. This is because Ti‐NC contributes to enhancing the inter‐molecular cross‐linking rather than intra‐molecular cross‐linking of guar gum molecular chains and yielding a tight three‐dimensional network structure in the cross‐linked guar gum gel.
Si/SiC heterojunction lateral double‐diffused metal oxide semiconductor field effect transistor with breakdown point transfer (BPT) terminal technology
Authors: Duan Baoxing , Huang Yunjia , Xing Jingyu , Yang Yintang 
Published: June 2019

A novel silicon (Si) on silicon carbide (SiC) lateral double‐diffused metal oxide semiconductor field effect transistor with deep drain region is proposed. Its main idea is transferring the breakdown point and utilising the high critical electric field of SiC material to suppress the curvature effect of the drain, which eventually alleviates the trade‐off relationship between breakdown voltage (BV) and specific on‐resistance (Ron,sp). Through the TCAD simulation, the results show that the BV is significantly improved from 240 V for conventional Si lateral double‐diffused metal oxide semiconductor (LDMOS) to 384 V for the proposed structure with the drift region length of 20 μm, increased by 60%. The figure‐of‐merit of the conventional Si LDMOS and the Si/SiC LDMOS are 2.04 and 4.26 MW/cm2, respectively. It indicates that the proposed structure has better performance than the Si counterpart. The influences of design parameters and interfacial charges on the device performance are also discussed in this work.
Flying far and fast: the distribution of distant hypervelocity star candidates fromGaiaDR2 data
Authors: de la Fuente Marcos R. , de la Fuente Marcos C. 
Published: June 2019

Context. Hypervelocity stars move fast enough to leave the gravitational field of their home galaxies and venture into intergalactic space. The most extreme examples known have estimated speeds in excess of 1000 km s−1. These can be easily induced at the centres of galaxies via close encounters between binary stars and supermassive black holes; however, a number of other mechanisms operating elsewhere can produce them as well.Aims. Recent studies suggest that hypervelocity stars are ubiquitous in the local Universe. In the Milky Way, the known hypervelocity stars are anisotropically distributed, but it is unclear why. Here, we usedGaiaData Release 2 (DR2) data to perform a systematic exploration aimed at confirming or refuting these findings.Methods. Our basic premise is that the farther the candidate hypervelocity stars are, the more likely they are to be unbound from the Galaxy. We used the statistical analysis of both the spatial distribution and kinematics of these objects to achieve our goals. Monte Carlo sampling techniques were applied to deal with large uncertainties. No global parallax zero-point correction was performed.Results. Focussing on nominal Galactocentric distances greater than 30 kpc, which are the most distant candidates, we isolated a sample with speeds in excess of 500 km s−1that exhibits a certain degree of anisotropy but remains compatible with possible systematic effects. We find that the effect of the Eddington-Trumpler-Weaver bias is important in our case: over 80% of our sources are probably located further away than implied by their parallaxes; therefore, most of our velocity estimates are lower limits. If this bias is as strong as suggested here, the contamination by disc stars may not significantly affect our overall conclusions.Conclusions. The subsample with the lowest uncertainties shows stronger, but obviously systematic, anisotropies and includes a number of candidates of possible extragalactic origin and young age with speeds of up to 2000 km s−1.
Hydrogen isotopic anomalies in extraterrestrial organic matter: role of cosmic ray irradiation and implications for UCAMMs
Authors: Augé B. , Dartois E. , Duprat J. , Engrand C. , Slodzian G. , Wu T. D. , Guerquin-Kern J. L. , Vermesse H. , Agnihotri A. N. , Boduch P. , Rothard H. 
Published: June 2019

Context. Micrometeorites represent, at timescales shorter than a few million years, the dominant source of extraterrestrial matter at the surface of the Earth. Analyses of ultracarbonaceous micrometeorites recovered from Antarctica, known as UCAMMs reveal an exceptionally N-rich organic matter associated with spatially extended high D enrichments. Experiments show that this specific organic matter might have been formed in the outer solar system by energetic irradiation of N-rich icy surfaces.
Aims. We experimentally investigate the hydrogen isotopic fractionation resulting from irradiation of normal and D-rich N2-CH4 ices by high energy ions, simulating the exposition to Galactic cosmic rays of icy bodies surfaces orbiting at large heliocentric distances.
Methods. Films of N2-CH4 ices and a N2-CH4/CD4/N2-CH4 “sandwich” ice were exposed to 129Xe13+ ion beams at 92 and 88 MeV. The chemical evolution of the samples was monitored using in situ Fourier transform infrared spectroscopy. After irradiation, targets were annealed to room temperature. The solid residues of the whole process left after ice sublimation were characterized in situ by infrared spectroscopy, and the hydrogen isotopic composition measured ex situ by imaging secondary ion mass spectrometry at the sub-micron scale (NanoSIMS).
Results. Irradiation leads to the formation of new molecules and radicals. After annealing, the resulting poly-HCN-like macro-molecular residue exhibits an infrared spectrum close to that of UCAMMs. The residue resulting from irradiation of N2-CH4 ices does not exhibit a significant deuterium enrichment comparable to that found in extraterrestrial organic matter. The residue formed by irradiation of D-rich ices shows the formation of isotopic heterogeneities with localised hotspots and an extended contribution likely due to the diffusion of the radiolytic products from the D-rich layer.
Conclusions. These results show that high-energy cosmic ray irradiation does not induce the large hydrogen isotopic fractionation observed at small spatial scale in interplanetary organics. By contrast, large D/H ratio heterogeneities at the sub-micron spatial scale in extraterrestrial organic matter can result from isotopically heterogeneous ices mixtures (i.e. condensed with different D/H ratios), which were transformed into refractory organic matter upon irradiation.
Validating the performance of the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) with in situ observations from DMSP and CHAMP
Authors: Themens David R. , Jayachandran P. Thayyil , McCaffrey Anthony M. 
Published: June 2019

The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) is a new empirical model of high latitude ionospheric electron density. While the introductory studies regarding E-CHAIM include validations, E-CHAIM’s topside model was notably excluded from independent validation using datasets not included in the model fitting. In this study, we undertake such a validation using in situ electron density observations from the Defense Meteorological Satellite Program (DMSP) constellation of satellites and the Challenging Mini-satellite Payload (CHAMP) mission. Through this validation, we show that E-CHAIM generally outperforms the International Reference Ionosphere (IRI) at DMSP orbit (~830 km altitude), with RMS errors of 8.3–9.8 × 109 e/m3 versus the IRI’s 1.2–1.3 × 1010 e/m3. E-CHAIM’s improvement over the IRI is consistent at all latitudes but is particularly noted in sub-auroral regions and is mainly limited to summer and equinox periods. At CHAMP orbit, E-CHAIM and the IRI are found to perform largely comparably, with E-CHAIM outperforming the IRI only marginally with RMS errors of 7.11 × 1010 e/m3 versus the IRI’s 7.48 × 1010 e/m3. This improvement is found to be largely constrained to sub-auroral latitudes with both models performing comparably at higher latitudes. An observed tendency for the IRI to overestimate electron density in the near-peak (at CHAMP orbit) and underestimate electron density at higher altitudes (DMSP orbit) appears to be consistent with previous work, which identified this pattern to result from shortcomings in the NeQuick topside function curvature at high latitudes.