bluuebunny/crossref_metadata_2025 huggingface dataset:
Deep eutectic solvents aqueous two-phase system based ultrasonically assisted extraction of ursolic acid (UA) from Cynomorium songaricum Rupr.
Authors: Zhang Xifeng , Zhang Ji
Published: December 2017

Deep eutectic solvents (DESs) are new green solvents that have attracted the attention of the scientific community mainly due to their unique properties and special characteristics, which are different from those of traditional solvents.A method based on ultrasonically assisted deep eutectic solvent aqueous two-phase systems( UAE-DES-ATPS) was developed for extracting ursolic acid (UA) from Cynomorium songaricum Rupr. Four different types of choline chloride-based DESs were prepared.Choline chloride-glucose (ChCl-Glu) exhibited good selective extraction ability. An optimum DES-ATPS of 36% (w/w) ChCl-Glu and 25% (w/w) K2HPO4 was considered to be a satisfactory system for extracting UA. Response surface methodology (RSM) method was used to optimize the extraction of UA using UAE-DES-ATPS. The optimum ultrasound-assisted conditions were as follows: solvent to solid ratio of 15:1 (g/g), ultrasound power of 470 W, and extraction time of 54 min. Compared with the conventional UAE method, the yields were basically the same, but the presented method had higher purity. The structure of UA did not change between pure UA and UA in the upper phase by UV–vis and FT-IR. This approach using ChCl-based DES-ATPS as a novel extraction system and ultrasound as a source of energy provided better choice for the separation of active components from other natural products.
Out of Asia: Mitochondrial evolutionary history of the globally introduced supralittoral isopod Ligia exotica
Authors: Hurtado Luis A , Mateos Mariana , Wang Chang , Santamaria Carlos A , Jung Jongwoo , Khalaji-Pirbalouty Valiallah , Kim Won
Published: December 2017

The native ranges and invasion histories of many marine species remain elusive due to a dynamic dispersal process via marine vessels. Molecular markers can aid in identification of native ranges and elucidation of the introduction and establishment process. The supralittoral isopod Ligia exotica has a wide tropical and subtropical distribution, frequently found in harbors and ports around the globe. This isopod is hypothesized to have an Old World origin, from where it was unintentionally introduced to other regions via wooden ships and solid ballast. Its native range, however, remains uncertain. Recent molecular studies uncovered the presence of two highly divergent lineages of L. exotica in East Asia, and suggest this region is a source of nonindigenous populations. In this study, we conducted phylogenetic analyses (Maximum Likelihood and Bayesian) of a fragment of the mitochondrial 16S ribosomal (r)DNA gene using a dataset of this isopod that greatly expanded previous representation from Asia and putative nonindigenous populations around the world. For a subset of samples, sequences of 12S rDNA and NaK were also obtained and analyzed together with 16S rDNA. Our results show that L. exotica is comprised of several highly divergent genetic lineages, which probably represent different species. Most of the 16S rDNA genetic diversity (48 haplotypes) was detected in East and Southeast Asia. Only seven haplotypes were observed outside this region (in the Americas, Hawai’i, Africa and India), which were identical or closely related to haplotypes found in East and Southeast Asia. Phylogenetic patterns indicate the L. exotica clade originated and diversified in East and Southeast Asia, and only members of one of the divergent lineages have spread out of this region, recently, suggesting the potential to become invasive is phylogenetically constrained.
Representation of time interval entrained by periodic stimuli in the visual thalamus of pigeons
Authors: Yang Yan , Wang Qian , Wang Shu-Rong , Wang Yi , Xiao Qian
Published: December 2017

Animals use the temporal information from previously experienced periodic events to instruct their future behaviors. The retina and cortex are involved in such behavior, but it remains largely unknown how the thalamus, transferring visual information from the retina to the cortex, processes the periodic temporal patterns. Here we report that the luminance cells in the nucleus dorsolateralis anterior thalami (DLA) of pigeons exhibited oscillatory activities in a temporal pattern identical to the rhythmic luminance changes of repetitive light/dark (LD) stimuli with durations in the seconds-to-minutes range. Particularly, after LD stimulation, the DLA cells retained the entrained oscillatory activities with an interval closely matching the duration of the LD cycle. Furthermore, the post-stimulus oscillatory activities of the DLA cells were sustained without feedback inputs from the pallium (equivalent to the mammalian cortex). Our study suggests that the experience-dependent representation of time interval in the brain might not be confined to the pallial/cortical level, but may occur as early as at the thalamic level.
Heat stress promotes longevity in budding yeast by relaxing the confinement of age-promoting factors in the mother cell
Authors: Baldi Sandro , Bolognesi Alessio , Meinema Anne Cornelis , Barral Yves
Published: December 2017

Although individuals of many species inexorably age, a number of observations established that the rate of aging is modulated in response to a variety of mild stresses. Here, we investigated how heat stress promotes longevity in yeast. We show that upon growth at higher temperature, yeast cells relax the retention of DNA circles, which act as aging factors in the mother cell. The enhanced frequency at which circles redistribute to daughter cells was not due to changes of anaphase duration or nuclear shape but solely to the downregulation of the diffusion barrier in the nuclear envelope. This effect depended on the PKA and Tor1 pathways, downstream of stress-response kinase Pkc1. Inhibition of these responses restored barrier function and circle retention and abrogated the effect of heat stress on longevity. Our data indicate that redistribution of aging factors from aged cells to their progeny can be a mechanism for modulating longevity.
A Physics‐Based Rock Friction Constitutive Law: Steady State Friction
Authors: Aharonov Einat , Scholz Christopher H.
Published: December 2017

Experiments measuring friction over a wide range of sliding velocities find that the value of the friction coefficient varies widely: friction is high and behaves according to the rate and state constitutive law during slow sliding, yet markedly weakens as the sliding velocity approaches seismic slip speeds. We introduce a physics‐based theory to explain this behavior. Using conventional microphysics of creep, we calculate the velocity and temperature dependence of contact stresses during sliding, including the thermal effects of shear heating. Contacts are assumed to reach a coupled thermal and mechanical steady state, and friction is calculated for steady sliding. Results from theory provide good quantitative agreement with reported experimental results for quartz and granite friction over 11 orders of magnitude in velocity. The new model elucidates the physics of friction and predicts the connection between friction laws to independently determined material parameters. It predicts four frictional regimes as function of slip rate: at slow velocity friction is either velocity strengthening or weakening, depending on material parameters, and follows the rate and state friction law. Differences between surface and volume activation energies are the main control on velocity dependence. At intermediate velocity, for some material parameters, a distinct velocity strengthening regime emerges. At fast sliding, shear heating produces thermal softening of friction. At the fastest sliding, melting causes further weakening. This theory, with its four frictional regimes, fits well previously published experimental results under low temperature and normal stress.
The Quasi‐monochromatic ULF Wave Boundary in the Venusian Foreshock: Venus Express Observations
Authors: Shan Lican , Mazelle Christian , Meziane Karim , Romanelli Norberto , Ge Yasong S. , Du Aimin , Lu Quanming , Zhang Tielong
Published: December 2017

The location of ultralow‐frequency (ULF) quasi‐monochromatic wave onset upstream of Venus bow shock is explored using Venus Express magnetic field data. We report the existence of a spatial foreshock boundary behind which ULF waves are present. We have found that the ULF wave boundary at Venus is sensitive to the interplanetary magnetic field (IMF) direction like the terrestrial one and appears well defined for a cone angle larger than 30°. In the Venusian foreshock, the inclination angle of the wave boundary with respect to the Sun‐Venus direction increases with the IMF cone angle. We also found that for the IMF nominal direction (θBX = 36°) at Venus' orbit, the value of this inclination angle is 70°. Moreover, we have found that the inferred velocity of an ion traveling along the ULF boundary is in a qualitative agreement with a quasi‐adiabatic reflection of a portion of the solar wind at the bow shock. For an IMF nominal direction at Venus, the inferred bulk speed of ions traveling along this boundary is 1.07 VSW, sufficiently enough to overcome the solar wind convection. This strongly suggests that the backstreaming ions upstream of the Venusian bow shock provide the main energy source for the ULF waves.
Assessing the Variability in the Relationship Between the Particulate Backscattering Coefficient and the Chlorophyll a Concentration From a Global Biogeochemical‐Argo Database
Authors: Barbieux Marie , Uitz Julia , Bricaud Annick , Organelli Emanuele , Poteau Antoine , Schmechtig Catherine , Gentili Bernard , Obolensky Grigor , Leymarie Edouard , Penkerc'h Christophe , D'Ortenzio Fabrizio , Claustre Hervé
Published: December 2017

Characterizing phytoplankton distribution and dynamics in the world's open oceans requires in situ observations over a broad range of space and time scales. In addition to temperature/salinity measurements, Biogeochemical‐Argo (BGC‐Argo) profiling floats are capable of autonomously observing at high‐frequency bio‐optical properties such as the chlorophyll fluorescence, a proxy of the chlorophyll a concentration (Chla), the particulate backscattering coefficient (bbp), a proxy of the stock of particulate organic carbon, and the light available for photosynthesis. We analyzed an unprecedented BGC‐Argo database of more than 8,500 multivariable profiles collected in various oceanic conditions, from subpolar waters to subtropical gyres. Our objective is to refine previously established Chla versus bbp relationships and gain insights into the sources of vertical, seasonal, and regional variability in this relationship. Despite some regional, seasonal and vertical variations, a general covariation occurs at a global scale. We distinguish two main contrasted situations: (1) concomitant changes in Chla and bbp that correspond to actual variations in phytoplankton biomass, e.g., in subpolar regimes; (2) a decoupling between the two variables attributed to photoacclimation or changes in the relative abundance of nonalgal particles, e.g., in subtropical regimes. The variability in the bbp:Chla ratio in the surface layer appears to be essentially influenced by the type of particles and by photoacclimation processes. The large BGC‐Argo database helps identifying the spatial and temporal scales at which this ratio is predominantly driven by one or the other of these two factors.
Direct Numerical Simulation of Oscillatory Flow Over a Wavy, Rough, and Permeable Bottom
Authors: Mazzuoli Marco , Blondeaux Paolo , Simeonov Julian , Calantoni Joseph
Published: December 2017

The results of a direct numerical simulation of oscillatory flow over a wavy bottom composed of different layers of spherical particles are described. The amplitude of wavy bottom is much smaller in scale than typical bed forms such as sand ripples. The spherical particles are packed in such a way to reproduce a bottom profile observed during an experiment conducted in a laboratory flow tunnel with well‐sorted coarse sand. The amplitude and period of the external forcing flow as well as the size of the particles are set equal to the experimental values and the computed velocity field is compared with the measured velocity profiles. The direct numerical simulation allows for the evaluation of quantities, which are difficult to measure in a laboratory experiment (e.g., vorticity, seepage flow velocity, and hydrodynamic force acting on sediment particles). In particular, attention is focused on the coherent vortex structures generated by the vorticity shed by both the spherical particles and the bottom waviness. Results show that the wavy bottom triggers transition to turbulence. Moreover, the forces acting on the spherical particles are computed to investigate the mechanisms through which they are possibly mobilized by the oscillatory flow. It was found that forces capable of mobilizing surface particles are strongly correlated with the particle position above the mean bed elevation and the passage of coherent vortices above them.
Malvinas Current Volume Transport at 41°S: A 24 Yearlong Time Series Consistent With Mooring Data From 3 Decades and Satellite Altimetry
Authors: Artana Camila , Ferrari Ramiro , Koenig Zoé , Sennéchael Nathalie , Saraceno Martin , Piola Alberto R. , Provost Christine
Published: December 2017

We combined altimetric data and the in situ data sets from three 10 years apart mooring deployments to compute a coherent and accurate volume transport time series of the Malvinas Current (MC) at 41°S. We used a method developed in Koenig et al. (2014) and explored three types of geostrophic shear to estimate the uncertainty derived from the lack of velocity data in the upper 300 m. The mean MC transport over 24 years in the upper 1,500 m is 37.1 ± 2.6 Sv and the standard deviation 6.6 ± 1 Sv. Since 1993, annual mean transports have varied from 32 to 41 Sv and the three in situ records corresponded to low annual mean transports. The MC transport time series is not stationary, its spectral content evolves with time showing significant energy at the 30–110 days, semiannual and annual period. The distribution of the MC volume transport anomalies is asymmetric, negatively skewed with larger negative anomalies than positive anomalies. Several transport maxima appear to result from cyclonic eddies that propagate northwestward following the 4,000–5,000 m isobaths and locally reinforce the circulation on the slope when they reach 41°S. During transport maxima, the northernmost extension of the Subantarctic Front (SAF) remains at its mean location (39.5°S). During minima, the SAF migrates southward of 41°S as positive anomalies shed by the Brazil Current overshoot moves westward onto the slope. Apart from continental trapped waves, changes in the MC volume transport at 41°S show no correlation with upstream conditions on the continental slope.
Identification of Tropical‐Extratropical Interactions and Extreme Precipitation Events in the Middle East Based On Potential Vorticity and Moisture Transport
Authors: de Vries A. J. , Ouwersloot H. G. , Feldstein S. B. , Riemer M. , El Kenawy A. M. , McCabe M. F. , Lelieveld J.
Published: December 2017

Extreme precipitation events in the otherwise arid Middle East can cause flooding with dramatic socioeconomic impacts. Most of these events are associated with tropical‐extratropical interactions, whereby a stratospheric potential vorticity (PV) intrusion reaches deep into the subtropics and forces an incursion of high poleward vertically integrated water vapor transport (IVT) into the Middle East. This study presents an object‐based identification method for extreme precipitation events based on the combination of these two larger‐scale meteorological features. The general motivation for this approach is that precipitation is often poorly simulated in relatively coarse weather and climate models, whereas the synoptic‐scale circulation is much better represented. The algorithm is applied to ERA‐Interim reanalysis data (1979–2015) and detects 90% (83%) of the 99th (97.5th) percentile of extreme precipitation days in the region of interest. Our results show that stratospheric PV intrusions and IVT structures are intimately connected to extreme precipitation intensity and seasonality. The farther south a stratospheric PV intrusion reaches, the larger the IVT magnitude, and the longer the duration of their combined occurrence, the more extreme the precipitation. Our algorithm detects a large fraction of the climatological rainfall amounts (40–70%), heavy precipitation days (50–80%), and the top 10 extreme precipitation days (60–90%) at many sites in southern Israel and the northern and western parts of Saudi Arabia. This identification method provides a new tool for future work to disentangle teleconnections, assess medium‐range predictability, and improve understanding of climatic changes of extreme precipitation in the Middle East and elsewhere.
Role of the Nucleus as a Sensor of Cell Environment Topography
Authors: Anselme Karine , Wakhloo Nayana Tusamda , Rougerie Pablo , Pieuchot Laurent
Published: December 2017

The proper integration of biophysical cues from the cell vicinity is crucial for cells to maintain homeostasis, cooperate with other cells within the tissues, and properly fulfill their biological function. It is therefore crucial to fully understand how cells integrate these extracellular signals for tissue engineering and regenerative medicine. Topography has emerged as a prominent component of the cellular microenvironment that has pleiotropic effects on cell behavior. This progress report focuses on the recent advances in the understanding of the topography sensing mechanism with a special emphasis on the role of the nucleus. Here, recent techniques developed for monitoring the nuclear mechanics are reviewed and the impact of various topographies and their consequences on nuclear organization, gene regulation, and stem cell fate is summarized. The role of the cell nucleus as a sensor of cell‐scale topography is further discussed.
Lasing Characteristics of CH3NH3PbCl3 Single‐Crystal Microcavities under Multiphoton Excitation
Authors: Yang Decheng , Xie Chao , Xu Xuhui , You Peng , Yan Feng , Yu Siu Fung
Published: December 2017

Photoluminescence of CH3NH3PbCl3 single crystals under multiphoton excitation is studied. The emission intensity and wavelength, which are related to the phase of the single crystals, are found to be dependent on the operating temperature and pressure. High optical gain (>110 cm−1 @ ≈395 nm) and high absorption coefficient (≈9 × 10−10 cm9 GW−5 @ 2400 nm) can also be obtained from the single crystals. With suitable design of the resonant optical amplification, lasing emission at ≈395 nm is demonstrated from the single‐crystal microcavities under 2400 nm excitation. Hence, it is verified that CH3NH3PbCl3 single crystals can offer new opportunities for novel nonlinear photonics applications.
Functionalized Flexible Soft Polymer Optical Fibers for Laser Photomedicine
Authors: Jiang Nan , Ahmed Rajib , Rifat Ahmmed A. , Guo Jingjing , Yin Yixia , Montelongo Yunuen , Butt Haider , Yetisen Ali K.
Published: December 2017

Optical waveguides allow propagating light through biological tissue in optogenetics and photomedicine applications. However, achieving efficient light delivery to deep tissues for long‐term implantation has been limited with solid‐state optical fibers. Here, a method is created to rapidly fabricate flexible, functionalized soft polymer optical fibers (SPOFs) coupled with silica fibers. A step‐index core/cladded poly(acrylamide‐co‐poly(ethylene glycol) diacrylate)/Ca alginate SPOF is fabricated through free‐radical polymerization in a mold. The SPOF is integrated with a solid‐state silica fiber coupler for efficient light delivery. The cladded SPOF shows ≈1.5‐fold increase in light propagation compared to the noncladded fiber. The optical loss of the SPOF is measured as 0.6 dB cm−1 at the bending angle of 70° and 0.28 dB cm−1 through a phantom tissue. The SPOF (inner Ø = 200 µm) integrated with a 21 gauge needle (inner Ø = 514 µm) is inserted within a porcine tissue. The intensity of light decreases ≈60%, as the SPOF is implanted as deep as 2 cm. Doped with fluorescent dye and gold nanoparticles, the SPOF fiber exhibits yellow‐red and red illumination. Living cells can also be incorporated within the SPOF with viability. The flexible SPOFs may have applications in photodynamic light therapy, optical biosensors, and photomedicine.
Construction of Vicinal Tetrasubstituted Stereogenic Centers via a Mannich‐Type Organocatalyzed Addition of Δ2‐Pyrrolin‐4‐ones to Isatin Imines
Authors: Ričko Sebastijan , Meden Anže , Ciber Luka , Štefane Bogdan , Požgan Franc , Svete Jurij , Grošelj Uroš
Published: December 2017

Racemic Δ2‐pyrrolin‐4‐ones (i. e. 4‐pyrrolones), easily available in two steps from N‐protected α‐amino acids, undergo organocatalysed asymmetric Mannich‐type addition to isatin‐derived ketimines to furnish the non‐racemic oxindole‐Δ2‐pyrrolin‐4‐one adducts, stereoselectively (up to 96% ee, dr≥15:1). The oxindole–pyrrolone products feature vicinal tetrasubstituted carbon stereocenters. The developed protocol has a broad substrate scope and tolerates diverse substituents at position C‐5 in 4‐pyrrolones and at positions N‐1 and C‐5/7 in isatin imines.

magnified image
Diastereoselective Electrophilic Trifluoromethylthiolation of Chiral Oxazolidinones: Access to Enantiopure α‐SCF3 Alcohols
Authors: Chachignon Hélène , Kondrashov Evgeniy V. , Cahard Dominique
Published: December 2017

Lithium imide enolates featuring Evans’ chiral oxazolidinone auxiliary were involved in diastereoselective α‐trifluoromethylthiolation with electrophilic SCF3 donors. Diastereopure products were isolated and converted to enantiopure α‐SCF3 alcohols without racemisation.

magnified image
Effects of composition and temperature of initial mixture on the formation and properties of polyurethane foam
Authors: Özdemir İ. Bedii , Akar Fırat
Published: December 2017

The purpose of the study is to optimize the initial conditions of the molding process of a multicomponent mixture into a refrigerator cabinet. Polyurethane foaming has been studied with different starting compositions and temperatures of the initial mixture. The kinetic mechanism has involved four reactions and species species. Using a standard recipe, the chemical kinetics and the numerical implementation have been first validated against the experimental values of the filling time and the density of the final foam. Thereafter, 11,763 different initial conditions are calculated. The results put in evidence that the filling time can be reduced without any significant change in the precursors of the rigidity of the foam. The final temperature of the foam has always remained lower than the limiting temperature so that thermal material deformations in the walls of the cabinet can be avoided. Increasing the physical blowing agent mass fraction beyond the standard recipe does not appear to be a useful option.
Thermal, mechanical properties and morphology of epoxy resins modified with light pyrolysis natural rubber
Authors: Zhao Xinyu , Wang Shifeng
Published: December 2017

Instead of using traditional functional liquid rubbers in toughening epoxy, light pyrolysis natural rubber (LPNR) obtained from scrap rubber was introduced to improve the toughness of cured epoxy resins. Epoxy blends were prepared by physically mixing the epoxy resins with various concentrations of LPNR. The structure, thermal, mechanical properties and morphology of the epoxy blends were investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, impact behavior, and scanning electron microscopy. It was found that the inclusion of 5 phr LPNR reached the maximum value in impact strength of the modified epoxies and the presence of LPNR enables the epoxy resins to fracture in a pattern more akin to ductile materials than in case of the neat epoxy which shows features of brittle rupture. The agglomeration of rubber particles decreased the toughness of epoxy resins modified with more LPNR. Meanwhile, the nearly unchanged glass transition temperature of LPNR epoxy samples illustrated weak interfacial adhesion existed between the rubber phase and epoxy matrix due to low compatibility and feeble combination between them. The thermal stability of modified epoxy resins went down because of the existence of LPNR domains inside the matrix. Overall, the LPNR should be further investigated to improve its compatibility and reinforce its combination with the epoxy resins to become a particularly efficient toughening agent because of its cheaper resource and contribution to environmental protection.
Preparation of hierarchical carbon nanotube–carbon fiber composites with coordination enhancement
Authors: Xue Han , A Nuona , Xiao Yinghong , Che Jianfei
Published: December 2017

Single‐walled carbon nanotubes–carbon fiber (SWNTs@CF) hierarchical fibers were prepared by electrophoretic deposition. To improve the interfacial strength between SWNTs and CF, a hexahapto‐metal complex, Cr(CO)6, was added to the electrophoretic system to prepare hierarchical fibers (SWNTs‐Cr(CO)6@CF). Results revealed that SWNTs covered CF surface entirely and formed a hierarchical structure. The morphology could be tailored from scattered nanotubes over forest to network by varying the deposition voltage. The hierarchical fibers were highly compatible with epoxy matrix, which could significantly increase the interfacial adhesion through interlocking epoxy matrix. Tensile properties were studied to investigate the effect of interfacial adhesion on mechanical properties of the reinforced composites. The polymeric composite, reinforced by SWNTs‐Cr(CO)6@CF, exhibited a remarkably high tensile strength of 519 MPa with the content ratio of 1.5:1 (Cr(CO)6:SWNTs). The improvement was up to 193% compared to the desized CF composite and 19% compared to SWNTs@CF composite. Additionally, thermogravimetric analyses demonstrated that the SWNTs‐Cr(CO)6@CF composite exhibited superior heat stability.
Nanosized Metal Phosphides Embedded in Nitrogen‐Doped Porous Carbon Nanofibers for Enhanced Hydrogen Evolution at All pH Values
Authors: Wang Min‐Qiang , Ye Cui , Liu Heng , Xu Maowen , Bao Shu‐Juan
Published: December 2017

Transition‐metal phosphides (TMPs) have emerged as promising catalyst candidates for the hydrogen evolution reaction (HER). Although numerous methods have been investigated to obtain TMPs, most rely on traditional synthetic methods that produce materials that are inherently deficient with respect to electrical conductivity. An electrospinning‐based reduction approach is presented, which generates nickel phosphide nanoparticles in N‐doped porous carbon nanofibers (Ni2P@NPCNFs) in situ. Ni2P nanoparticles are protected from irreversible fusion and aggregation in subsequent high‐temperature pyrolysis. The resistivity of Ni2P@NPCNFs (5.34 Ω cm) is greatly decreased by 104 times compared to Ni2P (>104 Ω cm) because N‐doped carbon NFs are incorporated. As an electrocatalyst for HER, Ni2P@NPCNFs reveal remarkable performance compared to other previously reported catalysts in acidic media. Additionally, it offers excellent catalytic ability and durability in both neutral and basic media. Encouraged by the excellent electrocatalytic performance of Ni2P@NPCNFs, a series of pea‐like MxP@NPCNFs, including Fe2P@NPCNFs, Co2P@NPCNFs, and Cu3P@NPCNFs, were synthesized by the same method. Detailed characterization suggests that the newly developed method could render combinations of ultrafine metal phosphides with porous carbon accessible; thereby, extending opportunities in electrocatalytic applications.
Design and Assembly of a Chiral Metallosalen‐Based Octahedral Coordination Cage for Supramolecular Asymmetric Catalysis
Authors: Tan Chunxia , Jiao Jingjing , Li Zijian , Liu Yan , Han Xing , Cui Yong
Published: December 2017

Supramolecular containers featuring both high catalytic activity and high enantioselectivity represent a design challenge of practical importance. Herein, it is demonstrated that a chiral octahedral coordination cage can be constructed by using twelve enantiopure Mn(salen)‐derived dicarboxylic acids as linear linkers and six Zn4‐p‐tert‐butylsulfonylcalix[4]arene clusters as tetravalent four‐connected vertices. The porous cage features a large hydrophobic cavity (≈3944 Å3) decorated with catalytically active metallosalen species and is shown to be an efficient and recyclable asymmetric catalyst for the oxidative kinetic resolution of racemic secondary alcohols and the epoxidation of olefins with up to >99 % enantiomeric excess. The cage architecture not only prevents intermolecular deactivation and stabilizes the Mn(salen) catalysts but also encapsulates substrates and concentrates reactants in the cavity, resulting in enhanced reactivity and enantioselectivity relative to the free metallosalen catalyst.
Could the low‐braking‐index pulsar PSR J1734–3333 evolve into a magnetar?
Authors: Gao Z.‐F. , Wang N. , Shan H.
Published: December 2017

The low braking index pulsar PSR J1734−3333 could be born with a superhigh internal magnetic field of 1014–1016 G, and undergo a supercritical accretion soon after its formation in a supernova explosion. The buried multipole magnetic fields will merger into a dipole magnetic field. Since the magnetic flow transfers from the core to the crust of the pulsar, its surface dipole field grows quickly at a power‐law form assumed until it saturates at the level of internal dipole field. The increase in surface dipole magnetic field results in the small braking index of n = 0.9. Keeping the current field‐growth index ϵ = 1.34, this pulsar will become a magnetar with surface dipole magnetic field at the equator Bd ∼ 2.6(1) × 1014 G and ∼5.3(2) × 1014 G after next 50 kyrs and 100 kys, respectively.
Utility of an abbreviated version of the stanford‐binet intelligence scales (5th ed.) in estimating ‘full scale’ IQ for young children with autism spectrum disorder
Authors: Twomey Conal , O'Connell Helen , Lillis Mary , Tarpey Sarah Louise , O'Reilly Gary
Published: December 2017

The fifth edition of the Stanford‐Binet Intelligence scales allows ‘full scale’ IQ (FSIQ) to be estimated using an abridged version of the test—the abbreviated battery IQ (ABIQ). Set within a public early intervention team service, the current cross‐sectional study investigated the utility of the ABIQ in estimating FSIQ for 40 children with autism spectrum disorder (ASD) aged 3–5 years. A strong ABIQ‐FSIQ association was yielded (r = 0.89; r2 = 0.808) and the ABIQ did not over‐estimate mean FSIQ above a clinically‐relevant threshold; however, clinically significant over‐estimation occurred in 17.5% of individual cases. While the findings provide support for the utility of the ABIQ in estimating FSIQ for young children with ASD, caution relating to the over‐estimation of FSIQ is warranted. Careful clinical judgment–ideally based on examination of previous cognitive assessment results (if available), thorough interactional observations, and close multi‐disciplinary consultation—is necessary to determine the applicability of the ABIQ to individual cases. Autism Res 2018, 11: 503–508. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

We investigated the utility of a shortened version of the Stanford‐Binet Intelligence Scales in estimating IQ for 40 young children with autism spectrum disorder (ASD). The findings provide qualified support for the instrument: acceptably accurate IQ estimation was achieved for most cases; but not so for a sizeable minority (17.5%). Careful clinical judgment is necessary to determine the applicability of the ABIQ to individual cases.
Emission analysis of Tb3+‐and Sm3+‐ion‐doped (Li2O/Na2O/K2O) and (Li2O + Na2O/Li2O + K2O/K2O + Na2O)‐modified borosilicate glasses
Authors: Naveen Kumar Reddy B. , Sailaja S. , Thyagarajan K. , Jho Young Dahl , Sudhakar Reddy B.
Published: December 2017

Four series of borosilicate glasses modified by alkali oxides and doped with Tb3+ and Sm3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B2O3 + 10SiO2 + 5MgO + R + 0.5(Tb2O3/Sm2O3) [where R = 10(Li2O /Na2O/K2O) for series A and C, and R = 5(Li2O + Na2O/Li2O + K2O/K2O + Na2O) for series B and D]. The X‐ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5D4 → 7F5 (543 nm) transition of the Tb3+ ions was registered under excitation at 379 nm for series A and B glasses. The emission spectra of the Sm3+ ions with the series C and D glasses showed strong reddish‐orange emission at 600 nm (4G5/2 →6H7/2) with an excitation wavelength λexci = 404 nm (6H5/2→4F7/2). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb3+ and Sm3+ ions was studied to optimize the potential alkali‐oxide‐modified borosilicate glass.
Sequential Multivariate Cell Culture Modeling at Multiple Scales Supports Systematic Shaping of a Monoclonal Antibody Toward a Quality Target
Authors: Sokolov Michael , Morbidelli Massimo , Butté Alessandro , Souquet Jonathan , Broly Hervé
Published: December 2017

The development of cell culture processes is highly complex and requires a large number of experiments on various scales to define the design space of the final process and fulfil the regulatory requirements. This work follows an almost complete process development cycle for a biosimilar monoclonal antibody, from high throughput screening and optimization to scale‐up and process validation. The key goal of this analysis is to apply tailored multivariate tools to support decision‐making at every stage of process development. A toolset mainly based on Principal Component Analysis, Decision Trees, and Partial Least Square Regression combined with a Genetic Algorithm is presented. It enables to visualize the sequential improvement of the high‐dimensional quality profile towards the target, provides a solid basis for the selection of effective process variables and allows to dynamically predict the complete set of product quality attributes. Additionally, this work shows the deep level of process knowledge which can be deduced from small scale experiments through such multivariate tools. The presented methodologies are generally applicable across various processes and substantially reduce the complexity, experimental effort as well as the costs and time of process development.
Perfusion applied to a 3D model of bone metastasis results in uniformly dispersed mechanical stimuli
Authors: Liu Boyuan , Han Suyue , Hedrick Brandon P. , Modarres‐Sadeghi Yahya , Lynch Maureen E.
Published: December 2017

Breast cancer most frequently metastasizes to the skeleton. Bone metastatic cancer is incurable and induces wide‐spread bone osteolysis, resulting in significant patient morbidity and mortality. Mechanical cues in the skeleton are an important microenvironmental parameter that modulate tumor formation, osteolysis, and tumor cell‐bone cell signaling, but which mechanical signals are the most beneficial and the corresponding molecular mechanisms are unknown. We focused on interstitial fluid flow based on its well‐known role in bone remodeling and in primary breast cancer. We created a full‐scale, microCT‐based computational model of a 3D model of bone metastasis undergoing applied perfusion to predict the internal mechanical environment during in vitro experimentation. Applied perfusion resulted in uniformly dispersed, heterogeneous fluid velocities, and wall shear stresses throughout the scaffold's interior. The distributions of fluid velocity and wall shear stress did not change within model sub‐domains of varying diameter and location. Additionally, the magnitude of these stimuli is within the range of anabolic mechanical signals in the skeleton, verifying that our 3D model reflects previous in vivo studies using anabolic mechanical loading in the context of bone metastasis. Our results indicate that local populations of cells throughout the scaffold would experience similar mechanical microenvironments.
Induction of autophagy and autophagy‐dependent apoptosis in diffuse large B‐cell lymphoma by a new antimalarial artemisinin derivative, SM1044
Authors: Cheng Chunyan , Wang Tao , Song Zhiqun , Peng Lijun , Gao Mengqing , Hermine Olivier , Rousseaux Sophie , Khochbin Saadi , Mi Jian‐Qing , Wang Jin
Published: December 2017

Diffuse large B‐cell lymphoma (DLBCL) is the most common form of non‐Hodgkin's lymphoma. R‐CHOP is currently the standard therapy for DLBCL, but the prognosis of refractory or recurrent patients remains poor. In this study, we synthesized a new water‐soluble antimalarial drug artemisinin derivative, SM1044. The treatment of DLBCL cell lines with SM1044 induces autophagy‐dependent apoptosis, which is directed by an accelerated degradation of the antiapoptosis protein Survivin, via its acetylation‐dependent interaction with the autophagy‐related protein LC3‐II. Additionally, SM1044 also stimulates the de novo synthesis of ceramide, which in turn activates the CaMKK2–AMPK–ULK1 axis, leading to the initiation of autophagy. Our findings not only elucidate the mechanism of autophagy‐dependent apoptosis in DLBCL cells, but also suggest that SM1044 is a promising therapeutic molecule for the treatment of DLBCL, along with R‐CHOP regimen.
Identification of a novel gene pairs signature in the prognosis of gastric cancer
Authors: Peng Pai‐Lan , Zhou Xiang‐Yu , Yi Guo‐Dong , Chen Peng‐Fei , Wang Fan , Dong Wei‐Guo
Published: December 2017

Current prognostic signatures need to be improved in identifying high‐risk patients of gastric cancer (GC). Thus, we aimed to develop a reliable prognostic signature that could assess the prognosis risk in GC patients. Two microarray datasets of GSE662254 (n = 300, training set) and GSE15459 (n = 192, test set) were included into analysis. Prognostic genes were screened to construct prognosis‐related gene pairs (PRGPs). Then, a penalized Cox proportional hazards regression model identified seven PRGPs, which constructed a prognostic signature and divided patients into high‐ and low‐risk groups according to the signature score. High‐risk patients showed a poorer prognosis than low‐risk patients in both the training set (hazard ratios [HR]: 6.086, 95% confidence interval [CI]: 4.341–8.533) and test set (1.773 [1.107–2.840]). The PRGPs signature also achieved a higher predictive accuracy (concordance index [C‐index]: 0.872, 95% CI: 0.846–0.897) than two existing molecular signatures (0.706 [0.667–0.744] for a 11‐gene signature and 0.684 [0.642–0.726] for a 24‐lncRNA signature) and TNM stage (0.764 [0.715–0.814]). In conclusion, our study identified a novel gene pairs signature in the prognosis of GC.
Diethylstilbestrol regulates mouse gubernaculum testis cell proliferation via PLC‐Ca2+‐CREB pathway
Authors: Zhang Xuan , Ping Hong‐yan , Li Jian‐hong , Duan Shou‐xin , Jiang Xue‐wu
Published: December 2017

Recent evidence suggested a positive correlation between environmental estrogens (EEs) and high incidence of abnormalities in male urogenital system, but the mechanism remains unclear. Diethylstilbestrol (DES) is a nonsteroidal synthetic estrogen that disrupts the morphology and proliferation of gubernaculum testis cells, but the underlying mechanism is unclear. In this study, mouse gubernaculum testis cells were pretreated with phospholipase C (PLC) inhibitor U‐73122 and then treated with DES. The results demonstrated that U‐73122 impaired DES‐evoked intracellular Ca2+ mobilization in gubernaculum testis cells and inhibited DES‐induced proliferation of gubernaculum testis cells. Mechanistically, we found that U‐73122 inhibited DES‐induced activation of cAMP‐response element binding protein (CREB) in gubernaculum testis cells. In conclusion, these data suggest that the effects of DES on mouse gubernaculum testis cells are mediated by PLC‐Ca2+‐CREB pathway.

Significance of the study

Environmental estrogens remain a serious threat to male reproductive health, and it is important to understand the mechanism by which EEs affect the male productive system. Here we explore potential mechanisms how the proliferation and contractility of gubernaculum testis cells are regulated by diethylstilbestrol. Our findings provide the first evidence that PLC‐Ca2+‐CREB signalling pathway mediates the nongenomic effects of diethylstilbestrol on gubernaculum testis cells. These findings provide new insight into the role of diethylstilbestrol in the aetiology of male reproductive dysfunction and will help develop better approaches for the prevention and therapy of male reproductive malformation.
Synergistic Chemical Synthesis and Self‐Assembly Lead to Three‐Dimensional b‐Oriented MFI Superstructures with Selective Adsorption and Luminescence Properties
Authors: Ma Xiaoting , Li Guannan , Tao Jiawei , Li Ping , Zheng Hongzhi , Li Shougui , Xu Yan
Published: December 2017

Higher‐order organization of inorganic nanoparticles with hierarchical architectures and tailored functionality is crucial in the nanofabrication of advanced materials. Here we demonstrate that three‐dimensional b‐oriented MFI superstructures can be organized by synergistic chemical synthesis and self‐assembly. The organization is accomplished by vapor treatment of tetrapropylammonium hydroxide (TPAOH)‐coated inorganic/bacterial cellulose scaffolds. TPA+ acts to direct nucleation and to mediate crystal morphology leading to oriented assembly of MFI crystals along crystallographic b‐axis, whereas bacterial cellulose holds the oriented assembly together forming three‐dimensional superstructures with macroporosity. Self‐supporting monoliths of the macroporous MFI show outstanding selective adsorption for para‐xylene and high adsorption capacity for volatile organic compounds. Incorporating luminescent molecules imparts the macroporous monoliths the new property of adsorption tunable luminescence that may act as an optical sensor indicating the level of adsorption. The current work opens a novel space for rational organization of hierarchical materials with tailored architectures and multifunctionality.
Photo‐responsive Bioactive Surfaces Based on Cucurbit[8]uril‐Mediated Host–Guest Interactions of Arylazopyrazoles
Authors: Wiemann Maike , Niebuhr Rebecca , Juan Alberto , Cavatorta Emanuela , Ravoo Bart Jan , Jonkheijm Pascal
Published: December 2017

A photoswitchable arylazopyrazole (AAP) derivative binds with cucurbit[8]uril (CB[8]) and methylviologen (MV2+) to form a 1:1:1 heteroternary host–guest complex with a binding constant of Ka=2×103 m−1. The excellent photoswitching properties of AAP are preserved in the inclusion complex. Irradiation with light of a wavelength of 365 and 520 nm leads to quantitative E‐ to Z‐ isomerization and vice versa, respectively. Formation of the Z‐isomer leads to dissociation of the complex as evidenced using 1H NMR spectroscopy. AAP derivatives are then used to immobilize bioactive molecules and photorelease them on demand. When Arg‐Gly‐Asp‐AAP (AAP–RGD) peptides are attached to surface bound CB[8]/MV2+ complexes, cells adhere and can be released upon irradiation. The heteroternary host–guest system offers highly reversible binding properties due to efficient photoswitching and these properties are attractive for designing smart surfaces.
Target Costing for Electricity Storage
Authors: Machhammer Otto , Zehner Peter
Published: December 2017

Die Amplitude der Strompreisschwankungen am Markt ist der Anreiz mit Strom zu handeln. In Deutschland sind die Netzgebühren und Abgaben für das Durchleiten von Strom höher als der Strompreis an der Börse. Stromspeicherung ist so kein lohnendes Geschäft. Dies kann sich nur ändern, wenn entsprechend hohe Vergütungen für die Abgabe von gespeichertem Strom gewährt werden. Das entwickelte Rechenmodell zeigt, dass ohne Förderung der Stromspeichertechnologie eine flächendeckende Versorgungssicherheit mit Strom, nur durch Erhalt bzw. Ausbau der konventionellen Kraftwerke als Backup möglich sein wird.
Developmental signature, synaptic connectivity and neurotransmission are conserved between vertebrate hair cells and tunicate coronal cells
Authors: Rigon Francesca , Gasparini Fabio , Shimeld Sebastian M , Candiani Simona , Manni Lucia
Published: December 2017

In tunicates, the coronal organ represents a sentinel checking particle entrance into the pharynx. The organ differentiates from an anterior embryonic area considered a proto‐placode. For their embryonic origin, morphological features and function, coronal sensory cells have been hypothesized to be homologues to vertebrate hair cells. However, vertebrate hair cells derive from a posterior placode. This contradicts one of the principle historical criteria for homology, similarity of position, which could be taken as evidence against coronal cells/hair cells homology. In the tunicates Ciona intestinalis and C. robusta, we found that the coronal organ expresses genes (Atoh, Notch, Delta‐like, Hairy‐b, and Musashi) characterizing vertebrate neural and hair cell development. Moreover, coronal cells exhibit a complex synaptic connectivity pattern, and express neurotransmitters (Glu, ACh, GABA, 5‐HT, and catecholamines), or enzymes for their synthetic machinery, involved in hair cell activity. Lastly, coronal cells express the Trpa gene, which encodes an ion channel expressed in hair cells. These data lead us to hypothesize a model in which competence to make secondary mechanoreceptors was initially broadly distributed through placode territories, but has become confined to different placodes during the evolution of the vertebrate and tunicate lineages.
Perineuronal nets in subcortical auditory nuclei of four rodent species with differing hearing ranges
Authors: Beebe Nichole L. , Schofield Brett R.
Published: December 2017

Perineuronal nets (PNs) are aggregates of extracellular matrix molecules that surround some neurons in the brain. While PNs occur widely across many cortical areas, subcortical PNs are especially associated with motor and auditory systems. The auditory system has recently been suggested as an ideal model system for studying PNs and their functions. However, descriptions of PNs in subcortical auditory areas vary, and it is unclear whether the variation reflects species differences or differences in staining techniques. Here, we used two staining techniques (one lectin stain and one antibody stain) to examine PN distribution in the subcortical auditory system of four different species: guinea pigs (Cavia porcellus), mice (Mus musculus, CBA/CaJ strain), Long‐Evans rats (Rattus norvegicus), and naked mole‐rats (Heterocephalus glaber). We found that some auditory nuclei exhibit dramatic differences in PN distribution among species while other nuclei have consistent PN distributions. We also found that PNs exhibit molecular heterogeneity, and can stain with either marker individually or with both. PNs within a given nucleus can be heterogeneous or homogenous in their staining patterns. We compared PN staining across the frequency axes of tonotopically organized nuclei and among species with different hearing ranges. PNs were distributed non‐uniformly across some nuclei, but only rarely did this appear related to the tonotopic axis. PNs were prominent in all four species; we found no systematic relationship between the hearing range and the number, staining patterns or distribution of PNs in the auditory nuclei.