Compact Morphology Research Articles

Poly(vinylidene fluoride-co-hexafluoropropylene) based tri-composites with zeolite and ionic liquid for electromechanical actuator and lithium-ion battery applications

In order to improve the multifunctionality of polymer composites for advanced applications a novel tri-composite material is presented based on the inclusion of MFI zeolite and the ionic liquid (IL) 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) in an electroactive poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer matrix. Tri-composites were produced by solvent casting with a relative overall filler content up to 40 wt.%. A compact film morphology is obtained, and the polymer degradation temperature and degree of crystallinity are independent on the filler content and type. On the other hand, the polymer crystalline phase depends on the presence of the IL but is independent of its content. Regarding the mechanical properties, it is observed that the IL has a plasticizing effect with a significant contribution to the reduction of the Young's modulus from 151 MPa for the pristine polymer to 92 MPa for the 30 wt.%/10 wt.% IL/MFI content sample. A high ionic conductivity value at room temperature of 3.9 × 10−5 S.cm−1 was obtained for the tri-composite with the highest IL content (30 wt.%/10 wt.% IL/MFI). The tri-composite system was studied as solid polymer electrolyte (SPE) for battery and bending actuator applications, demonstrating the multifunctionality of the material. The sample with the best cycling performance was observed for the highest MFI content (10 wt.%/30 wt.% IL/MFI) with a discharge capacity value of 110 mAh.g−1 and maintaining almost 80% of its initial capacity after 30 cycles at the C/10 rate. Regarding to the bending performance, the best bending actuation was detected for highest IL content (30 wt.%/10 wt.% IL/MFI), related to the ionic conductivity of the sample. Thus, it is demonstrated that the new tri-composite system, due to its tunable characteristics as a function of the relative IL and zeolite contents, is suitable for a next generation of multifunctional polymer composite materials for advanced applications.

The interplay of precipitation of ordered compounds and interfacial segregation in Al‐Cu‐Hf‐Si alloys for high-temperature strength

Achieving high yield strength (250-270 MPa) at elevated temperatures (250 °C and above) for precipitation strengthened aluminium-copper (Al-Cu) alloys still remains a challenge for the alloy designers. This paper presents a systematic progression of the microstructure evolution in a binary Al-0.3Hf, ternary Al-0.3Hf-0.3Si and quaternary Al-2Cu-0.3Hf-0.3Si (in at%) alloys. A quantitative understanding of the role that Hf and Si plays in promoting ordered precipitates and the metastable Al-Cu intermetallic compounds θ"/θ' has been attempted. The initial microstructure is guided by the initial precipitation of primary phases, triggering the formation of Hf-rich dendrites and finally, the Si/Cu segregation at boundaries. Ageing of binary Al-Hf alloy results in precipitation of L12 ordered phase via discontinuous (cellular) process. Si, however, promotes a continuous precipitation process, resulting in the formation of coherent and spherical L12 ordered phase in the matrix. The role of these ordered precipitates in influencing the precipitation of θ"/θ' compounds in quaternary copper containing alloy was explored in detail, including their coarsening and mechanical properties at elevated temperatures. The compact morphology developed in the alloy results in yield strength of 445 ± 8 MPa at room temperature (25 °C). The yield strength evolves through the interaction of L12and θ"/θ' ordered phases with the α-Al matrix. The coarsening of θ' phase was slowed down due to Hf segregation at a semi-coherent interface and led to a thermally stable microstructure that resulted in yield strength of 256 ± 8 MPa at 250 °C.

Preparation of nanocrystalline Ni–Mo and Ni–Mo–ZrO2 coating and investigation of its corrosion resistance and wear behaviors

Nanocrystalline Ni–Mo and Ni–Mo–ZrO2 coatings were designed and successfully fabricated via electrodeposition process in direct current mode. Impacts of molybdate and ZrO2 nanoparticles, cathodic current density (ic) on surface, structure and performance of Ni–Mo alloy were analyzed. Electrochemical behaviors were evaluated by electrochemical impedance method in sodium chloride solution. A more compact and consistent surface morphology was prepared by introducing molybdate in nickel. Grain sizes of Ni–Mo alloy decreased as molybdate increased from 2 to 6 g L−1, and enlarged as ic increased. After incorporation of ZrO2, the grains initially decreased to 12 nm and later increased to 18 nm. The structure of the deposit is a face-centered cubic phase. With the increase of molybdate content, the preferential Ni (220) crystal plane was changed to oriented (111) plane. The Ni–Mo alloy comprises 91 wt% Ni and 5.4 wt% Mo. Ra of Ni–Mo–ZrO2 was 73 ± 4 nm. Ni–Mo alloys obtained at 20 mA cm−2 and 2 g L−1 molybdate possess the best corrosion-resistant behavior. Incorporation of ZrO2 can strengthen electrochemical stability and anti-wear behavior of Ni–Mo alloy. The inclusion of ZrO2 refined the grain size from 18 to 12 nm. The Ni–Mo/ZrO2 coatings electrodeposited under 2–4 g L−1 Na2MoO4·2H2O, 20–40 mA cm−2, 10–15 g L−1 ZrO2 have excellent wear and corrosion resistance.

Fluorosubstitution Boosting 2D Ruddlesden–Popper CsPbI3 with High Stability and Efficiency

Bulky organic cations exhibit significant roles in improving the phase stability of CsPbI3 by reducing its dimension with higher steric hindrance. However, the insulative properties of organic cations impede the carrier transition and damage the device performance. Herein, a new aromatic cation of 4‐fluorobenzenaminium (FPA+) in the 2D CsPbI3 to act as a spacer cation, is reported. Based on the theoretical simulation and experimental characterization for materials properties, film quality, and device performance, the large dipole moment and electronic inductive effect of FPA+ cations improve the hydrogen bond between H and I atoms, which is beneficial to realizing controllable crystallization quality. Therefore, the whole quality of 2D CsPbI3 film is improved with a larger grain size, compact morphology, and low trap density. As a result, the (FPA)2Cs4Pb5I16 perovskite solar cell delivers a power conversion efficiency of 15.18%, significantly higher than that of PA‐based (14.32%) perovskite solar cells. Herein, an in‐depth understanding of fluoro‐substituted organic cations is provided and is beneficial to the design and synthesis of new organic molecules in 2D perovskite.

A Ti3C2Tx-carbon black-acrylic epoxy coating for 304SS bipolar plates with enhanced corrosion resistant and conductivity

A conducting and anticorrosive coating is crucial for the application of metal bipolar plates (BP) in proton exchange membrane fuel cell (PEMFC). In this work, a Ti3C2Tx (T)-carbon black (C)-acrylic epoxy (AE) coating is prepared on 304 stainless steel (SS) with enhanced corrosion resistance and conductivity. The corrosion resistance of the T-C-AE coating is investigated in a 0.5 M H2SO4 solution as compared to the AE, T, and T-AE coatings. The T-C-AE coated 304SS exhibits the strongest corrosion resistance with the most positive corrosion potential and the lowest corrosion current density of 0.00673 μA cm−2 in all the samples, while retaining intact and compact surface morphology with the lowest metal ion dissolution even after immersed for 720 h. The addition of Ti3C2Tx and carbon black into the AE matrix greatly decreases interfacial contact resistance (ICR), and the T-C-AE coating achieves a low ICR of 15.5 mΩ cm−2 under 140 N cm−2 compaction force. The excellent anticorrosion performance is mainly attributed to the physical barrier and the cathodic protection provided by the stacked Ti3C2Tx (MXene) nanosheets in the T-C-AE coating. This eco-friendly, conducting, and anticorrosive T-C-AE coating has a good application prospect on SS BP of PEMFC.

Pulse electrodeposition of aluminium coatings from molten salt bath; effect of processing parameters on the coatings’ corrosion and wear behaviour

ABSTRACT In this study, Al coatings were pulse electrodeposited from a molten salt electrolyte onto copper substrates. The effects of applied peak current density, pulse current frequency and duty cycle on the morphology, microstructure, corrosion behaviour and tribological properties of the coatings were investigated by scanning electron microscopy, X-ray diffraction, potentiodynamic polarisation, electrochemical impedance spectroscopy and pin-on-disc wear test methods. The results showed that the changes in processing parameters changed the morphological and microstructural features of the resulting coatings, which in turn affected their corrosion and wear behaviours. Coatings with smoother surfaces, finer crystallite size and more compact morphologies that were electrodeposited at higher applied peak current density (up to 80 mA cm−2), higher pulse current frequency (up to 50 Hz) and higher duty cycle (up to 50%) exhibited more corrosion and wear resistance than the others.

In Situ Construction of Sodiophilic Alloy Interface Enabled Homogenous Na Nucleation and Deposition for Sodium Metal Anode

The sodium (Na) metal anode is a desirable anode for the next-generation batteries because of its abundant resources and the high specific capacity. However, the poor cyclic stability hinders its practical application. In this study, we report a facile strategy of in situ constructing sodiophilic alloying sites for Na metal anodes by using zinc (Zn) foil as the current collector, which enables smooth and compact deposition morphology and excellent cyclic stability. The Zn current collector and the initial deposited Na generate a NaZn13 alloy interface, which can guide the subsequent plating/stripping behavior of Na. As a result, the Na metal anode with Zn current collector exhibits ultrahigh stability with Coulombic efficiency of 99.87% (over 450 cycles at 1 mA cm−2 for 1 mAh cm−2). Furthermore, the impressive capacity retention (98.5% after 40 cycles at 0.5 C) in Zn∣∣NVP (Na3V2(PO4)3) batteries suggests the anticipated application prospect of Zn current collector in anode-free Na metal batteries, which opens up a new way for the evolution of the next generation of safe and efficient Na metal anodes.

Dissecting Nearby Galaxies with piXedfit. II. Spatially Resolved Scaling Relations among Stars, Dust, and Gas

We study spatially resolved scaling relations among stars, dust, and gas in ten nearby spiral galaxies. In a preceding paper, we have derived spatially resolved properties of the stellar population and dust by a panchromatic spectral energy distribution fitting using piXedfit. Now, we investigate resolved star formation (–ΣSFR–Σ*) and dust scaling relations. While the relations with all subgalactic regions of the galaxies are reasonably tight (σ ≲ 0.3 dex), we find that most of the scaling relations exhibit galaxy-to-galaxy variations in normalization and shape. Only two relations of Σdust–Σgas and Σdust– do not show noticeable galaxy-to-galaxy variations among our sample galaxies. We further investigate the correlations among the scaling relations. We find significant correlations among the normalization of the –ΣSFR–Σ* relations, which suggest that the galaxies with higher levels of resolved H2 fraction () tend to have higher levels of resolved star formation efficiency (SFE) and specific star formation rate (sSFR). We also observe that the galaxies with higher levels of resolved dust-to-stellar mass ratios tend to have higher levels of resolved sSFR, SFE, and . Moreover, we find that the galaxies with higher global sSFR and less compact morphology tend to have higher levels of the resolved sSFR, SFE, and , which can explain the variations in the normalization of the –ΣSFR–Σ* relationships. Overall, we observe indications of the contributions of both global and local factors in governing the star formation process in galaxies.

Polyanilines from spent battery powder and activated carbon: Electrodes for asymmetric supercapacitor cell

AbstractThis work aims to use the electro‐active materials for energy storage application from the waste raw material source, readily and indigenously available materials. Nowadays, the use of waste sources to prepare electro‐active materials for energy storage applications is trending due to their low‐cost, high availability, reduced environmental problems, and so forth. In this direction, Polyaniline (PANI) is prepared using a MnO2 oxidant collected from waste Zn‐C cells. PANI displayed a compact and interconnected granular morphology with a surface area (39 m2 g−1), pore volume (0.19 cm3 g−1), and pore diameter (2.2 nm). Activated carbon (AC) has a surface area (860 m2 g−1), pore volume (199 cm3 g−1), and pore diameter (1.2 nm) is purchased locally. FT‐IR, XRD, and EDAX spectra support the formation of polyaniline salt with a small amount of Mn and Zn. The asymmetric cell is constructed using a PANI as a positive electrode and carbon as negative electrode material. The cell (PANI//AC) shows a high specific capacitance of 157 F g−1 at a current density of 5 mA cm−2. The cell offers a cycle life stability of 5000 cycles with a coulombic efficiency of 93% at a current density of 10 mA cm−2.

The WISE-2MASS Survey: Red Quasars Into the Radio Quiet Regime

We present a highly complete sample of broad-line (Type 1) QSOs out to z ∼ 3 selected by their mid-infrared colors, a method that is minimally affected by dust reddening. We remove host-galaxy emission from the spectra and fit for excess reddening in the residual QSOs, resulting in a Gaussian distribution of colors for unreddened (blue) QSOs, with a tail extending toward heavily reddened (red) QSOs, defined as having E(B − V) > 0.25. This radio-independent selection method enables us to compare red and blue QSO radio properties in both the FIRST (1.4 GHz) and VLASS (2–4 GHz) surveys. Consistent with recent results from optically selected QSOs from SDSS, we find that red QSOs have a significantly higher detection fraction and a higher fraction of compact radio morphologies at both frequencies. We employ radio stacking to investigate the median radio properties of the QSOs including those that are undetected in FIRST and VLASS, finding that red QSOs have significantly brighter radio emission and steeper radio spectral slopes compared with blue QSOs. Finally, we find that the incidence of red QSOs is strongly luminosity dependent, where red QSOs make up >40% of all QSOs at the highest luminosities. Overall, red QSOs comprise ∼40% of higher luminosity QSOs, dropping to only a few percent at lower luminosities. Furthermore, red QSOs make up a larger percentage of the radio-detected QSO population. We argue that dusty AGN-driven winds are responsible for both the obscuration as well as excess radio emission seen in red QSOs.

Intracanopy lighting strategies to improve green bush bean (Phaseolus vulgaris) compatibility with vertical farming

Now that multi-tiered plant factories with artificial lighting (PFALs) have demonstrated sufficient proof of concept for leafy green and microgreen production; the next challenge is to determine the optimal environment conditions and horticultural management practices required to produce nutrient-dense plant-based protein (PBP) crops within these advanced controlled environment systems (CES). Sole-source lighting within PFALs is energetically and economically expensive, as such, optimizing light distribution through intracanopy lighting could be a key factor in expanding the number of crops compatible with PFAL production. An ideal PBP PFAL crop will have a compact morphology (height, area, volume), be compatible with low-light environments, be self-pollinating, and have a relatively short life cycle. The objectives of this study were to 1) evaluate a selection of green bush bean cultivars (Phaseolus spp.) within a CES to determine which currently available cultivar is most compatible with PFAL production and 2) determine if the addition of intracanopy LED lighting could further improve cultivar compatibility with PFAL systems. The bush bean cultivar “Bronco” was selected after a 40-day flowering and 60-day fruiting trial for its compact morphology and yield (count, fresh weight). Intracanopy LED lighting trials on “Bronco” demonstrated a reduced shoot height (16%), increased bean count (22%), and increased fresh bean weight (17%) relative to plants produced with overhead lighting alone. While intracanopy lighting improved green bush bean compatibility with PFAL production, the additional light applied within the canopy increased the cost of production.

Effect of annealing on mechanical properties and thermal stability of ZrCu/O nanocomposite amorphous films synthetized by pulsed laser deposition

Binary ZrCu nanocomposite amorphous films are synthetized by pulsed laser deposition (PLD) under vacuum (2 × 10−3 Pa) and 10 Pa He pressure, leading to fully amorphous compact and nanogranular morphologies, respectively. Then, post-thermal annealing treatments are carried out to explore thermal stability and crystallization phenomena together with the evolution of mechanical properties. Compact films exhibit larger thermal stability with partial crystallization phenomena starting at 420 °C, still to be completed at 550 °C, while nanogranular films exhibit early-stage crystallization at 300 °C and completed at 485 °C. The microstructural differences are related to a distinct evolution of mechanical properties and residual stress, with compact TFMGs showing the highest values of Young’s modulus (157 GPa), hardness (12 GPa), strain rate sensitivity (0.096), and local residual stress (+691 MPa) upon annealing at 550 °C, while nanogranular films reach the maximum values of mechanical properties at 485 °C followed by relaxation at higher temperatures due to complete crystallization. We show that PLD in combination with post-thermal annealing can generate different families of amorphous films with varying nanoscale morphologies, resulting in tunable mechanical properties and thermal stability, which can thus be used for designing novel film configurations for different fields of application.

Pleiotropic Effect of the compactum Gene and Its Combined Effects with Other Loci for Spike and Grain-Related Traits in Wheat.

Club wheat (Triticum aestivum ssp. compactum) with a distinctly compact spike morphology was conditioned by the dominant compactum (C) locus on chromosome 2D and resulted in a redistribution of spike yield components. The disclosure of the genetic basis of club wheat was a prerequisite for the development of widely adapted, agronomically competitive club wheat cultivars. In this study, we used a recombinant inbred line population derived from a cross between club wheat Hiller and modern cultivar Yangmai 158 to construct a genetic linkage map and identify quantitative trait loci associated with 15 morphological traits. The club allele acted in a semi-dominant manner and the C gene was mapped to 370.12–406.29 Mb physical region on the long arm of 2D. Apart from compact spikes, C exhibited a pleiotropic effect on ten other agronomic traits, including plant height, three spike-related traits and six grain-related traits. The compact spike phenotype was correlated with decreased grain size and weight, but with an increase in floret fertility and grain number. These pleiotropic effects make club wheat have compatible spike weight with a normal spike from common wheat. The genetic effects of various gene combinations of C with four yield-related genes, including Ppd-D1, Vrn-D3, Rht-B1b and Rht8, were evaluated. C had no epistatic interaction with any of these genes, indicating that their combinations would have an additive effect on other agronomically important traits. Our research provided a theoretical foundation for the potentially effective deployment of C gene into modern breeding varieties in combination with other favorable alleles.

Lithium-Ion Battery Solid Electrolytes Based on Poly(vinylidene Fluoride)-Metal Thiocyanate Ionic Liquid Blends.

Solid polymer electrolytes (SPEs) are required to improve battery safety through the elimination of the liquid electrolyte solution in current batteries. This work is focused on the development of a hybrid SPE based on poly(vinylidene fluoride), PVDF, and 1-butyl-3-methylimidazolium cobalt(II) isothiocyanate, [BMIM]2[(SCN)4Co] magnetic ionic liquid (MIL), and its battery cycling behavior at room temperature. The addition of MIL in filler contents up to 40 wt % to the PVDF matrix does not influence the compact morphology of the samples obtained by solvent casting. The polar β-phase of PVDF increases with increasing MIL content, whereas the degree of crystallinity, thermal degradation temperature, and mechanical properties of the MIL/PVDF blends decrease with increasing MIL content. The ionic conductivity of the MIL/PVDF blends increases both with temperature and MIL content, showing the highest ionic conductivity of 7 × 10-4 mS cm-1 at room temperature for the MIL/PVDF blend with 40 wt % of MIL. The cathodic half-cells prepared with this blend as SPE show good reversibility and excellent cycling behavior at different C-rates, with a discharge capacity of 80 mAh g-1 at a C/10-rate with a Coulombic efficiency of 99%. The developed magnetic SPE, with excellent performance at room temperature, shows potential for the implementation of sustainable lithium-ion batteries, which can be further tuned by the application of an external magnetic field.

Fabrication and Characterization of Buccal Film Loaded Self-emulsifying Drug Delivery SystemcontainingLysiphyllum strychnifolium Stem Extracts.

Lysiphyllum strychnifolium has long been used as a popular herbal medicinal plant for treating fever and alcohol intoxication. This study aimed to prepare buccal film for L. strychnifolium stem extracts. These extracts were less soluble in water and were therefore loaded in self-emulsifying systems before being mixed into the film. Astilbin was selected as a chemical marker in L. strychnifolium stem extracts. Firstly, the L. strychnifolium stem extracts were entrapped in the self-emulsifying systems which were designed and optimized based on 32 factorial design. The optimal formulation was 0.60 g of surfactant-co-surfactant mixture (Tween® 80 and polyethylene glycol 400 in the ratio of 7.5:1) and 0.40 g of caprylic/capric triglyceride. Secondly, the optimal self-emulsifying system was loaded in the polymeric film which consisted of polyvinyl alcohol blended with poloxamer 407 using glycerin as a plasticizer. The properties of the prepared buccal film were unchanged, and the film showed an amorphous state, indicating all ingredients might be completely dissolved in the film. The buccal film could be placed in direct contact with the mouth without oral mucosal irritation, and showed a smooth and homogeneous surface with a rough and compact cross-sectional morphology. Astilbin content in the buccal film was 61.39 ± 11.45 µg/cm2. Astilbin was released from the buccal film while the permeation rate was low. The release mechanism was both swelling and diffusion, and followed anomalous or non-Fickian transfer. The permeability coefficient of the cumulative amount of astilbin permeated from buccal film was 1.0192 ± 0.1395 ×10-3 cm/h. Thus, the buccal film can be prepared by using a self-emulsifying system for herbal applications and shows potential as a safe and convenient form of oral drug administration.

Dual constraints with ALMA: new [O iii] 88-μm and dust-continuum observations reveal the ISM conditions of luminous LBGs at z ∼ 7

ABSTRACT We present new [${\rm O\, {\small III}}$] 88-$\mu \mathrm{{m}}$ observations of five bright z ∼ 7 Lyman-break galaxies spectroscopically confirmed by ALMA through [${\rm C\, {\small II}}$] 158 $\mu \mathrm{{m}}$, unlike recent [${\rm O\, {\small III}}$] detections where Lyman α was used. This nearly doubles the sample of Epoch of Reionization galaxies with robust (5σ) [${\rm C\, {\small II}}$] and [${\rm O\, {\small III}}$] detections. We perform a multiwavelength comparison with new deep HST images of the rest-frame UV, whose compact morphology aligns well with [${\rm O\, {\small III}}$] tracing ionized gas. In contrast, we find more spatially extended [${\rm C\, {\small II}}$] emission likely produced in neutral gas, as indicated by an [${\rm N\, {\small II}}$] 205-$\mu \mathrm{{m}}$ non-detection in one source. We find a correlation between the optical ${[{\rm O\, {\small III}}]}+ {\mathrm{H\,\beta }}$ equivalent width and [${\rm O\, {\small III}}$]/[${\rm C\, {\small II}}$], as seen in local metal-poor dwarf galaxies. cloudy models of a nebula of typical density harbouring a young stellar population with a high-ionization parameter adequately reproduce the observed lines. Surprisingly, however, our models fail to reproduce the strength of [${\rm O\, {\small III}}$] 88-$\mu \mathrm{{m}}$, unless we assume an α/Fe enhancement and near-solar nebular oxygen abundance. On spatially resolved scales, we find [${\rm O\, {\small III}}$]/[${\rm C\, {\small II}}$] shows a tentative anticorrelation with infrared excess, LIR/LUV, also seen on global scales in the local Universe. Finally, we introduce the far-infrared spectral energy distribution fitting code mercurius to show that dust-continuum measurements of one source appear to favour a low dust temperature and correspondingly high dust mass. This implies a high stellar metallicity yield and may point towards the need of dust production or grain-growth mechanisms beyond supernovae.

Influence of crystallite morphology on the ablative behaviors of CVD-TaC coatings prepared on C/C composites beyond 2100 °C

Three types of TaC coatings with different crystallite morphologies were successfully fabricated on carbon/carbon composites by chemical vapor deposition, and their ablation performance was investigated. The TaC coating with acicular crystal exhibited a more favorable ablation resistance as certified by the compact surface morphology and lower ablation rates due to the formation of a stable oxide layer. As for others, the powdering of TaC coating with nano crystal induced by gas evaporation of acute oxidation, and the exfoliation of TaC coating with columnar crystal caused by grain overgrowth all resulted in their weak protection for C/C substrates during ablation.

Tracking the urban expansion and its driving mechanisms behind Xinjiang Production and Construction Corps (XPCC): Evidence from morphology and landscapes

Cities are diverse, with their formation and expansion having various driving forces. Xinjiang Production and Construction Corps (XPCC) cities represent an emerging category in China's urban system. They have evolved into a special organisation integrating ‘party, government, military, and enterprises’ and are located in Xinjiang, the frontier region of north-western China. Investigation of such urban characteristics is helpful to enrich our diverse cognitions on cities. The purpose of this paper is to trace the growth history of XPCC cities and explore their evolution-related characteristics, modes, and driving mechanisms in terms of spatial morphology and landscapes in the process of urban expansion by utilising remote sensing interpretation data. This study led to four main conclusions. (1) The role of the XPCC in maintaining the long-term stability and prosperity of the frontier is increasingly valued across the nation, thus leading to a major increase in the quantity and quality of XPCC cities. (2) These cities have a unique spatial layout around two deserts and the border characterised by ‘two rings and one line’; however, their distribution is relatively scattered. (3) The expansion of XPCC cities has become prominent along with the restructuring of land use, with wasteland reclaiming being a salient attribute of their built-up land expansion, while also protecting cultivated land. Most cities reveal a more complex and less compact morphology. (4) The external government's promotion and regulation, the basic shaping of the natural geographical environment, the internal boosting of economic increase and industrial restructuring, and the special reshaping of the XPCC-local relationship are key driving factors behind the urban temporal-spatial evolution. Overall, this study supplements current knowledge on frontier cities within the Chinese context and thus helps to improve understanding of the urban theoretical research of government behaviours and the multi-dynamics of urban development.

Development and evaluation of a novel xeno-free culture medium for human-induced pluripotent stem cells

BackgroundHuman-induced pluripotent stem cells (hiPSCs) are considered an ideal resource for regenerative medicine because of their ease of access and infinite expansion ability. To satisfy the sizable requirement for clinical applications of hiPSCs, large-scale, expansion-oriented, xeno-free, and cost-effective media are critical. Although several xeno-free media for hiPSCs have been generated over the past decades, few of them are suitable for scalable expansion of cultured hiPSCs because of their modest potential for proliferation and high cost.MethodsIn this study, we developed a xeno-free ON2/AscleStem PSC medium (ON2) and cultured 253G1 hiPSCs on different matrices, including iMatrix-511 and gelatin nanofiber (GNF) in ON2. Over 20 passages, we evaluated cell proliferation by doubling times; pluripotency by flow cytometry, immunofluorescence staining and qRT-PCR; and differentiation ability by three germ layer differentiation in vitro and teratoma formation in severe combined immunodeficiency mice, followed by histological analysis. In addition, we compared the maintenance effect of ON2 on hiPSCs with StemFit® AK02 (AK02N) and Essential 8™ (E8). Besides 253G1 hiPSCs, we cultivated different hiPSC lines, including Ff-l01 hiPSCs, ATCC® ACS-1020™ hiPSCs, and Down’s syndrome patient-specific ATCC® ACS-1003™ hiPSCs in ON2.ResultsWe found that 253G1 hiPSCs in ON2 demonstrated normal morphology and karyotype and high self-renewal and differentiation abilities on the tested matrices for over 20 passages. Moreover, 253G1 hiPSCs kept on GNF showed higher growth and stemness, as verified by the shorter doubling time and higher expression levels of pluripotent markers. Compared to AK02N and E8 media, 253G1 hiPSCs grown in ON2 showed higher pluripotency, as demonstrated by the increased expression level of pluripotent factors. In addition, all hiPSC lines cultivated in ON2 were able to grow for at least 10 passages with compact clonal morphology and were positive for all detected pluripotent markers.ConclusionsOur xeno-free ON2 was compatible with various matrices and ideal for long-term expansion and maintenance of not only healthy-derived hiPSCs but also patient-specific hiPSCs. This highly efficient medium enabled the rapid expansion of hiPSCs in a reliable and cost-effective manner and could act as a promising tool for disease modeling and large-scale production for regenerative medicine in the future.

Unraveling the Innermost Jet Structure of OJ 287 with the First GMVA + ALMA Observations

We present the first very long baseline interferometric (VLBI) observations of the blazar OJ 287 carried out jointly with the Global Millimeter VLBI Array (GMVA) and the phased Atacama Large Millimeter/submillimeter Array (ALMA) at 3.5 mm on 2017 April 2. The participation of phased ALMA has not only improved the GMVA north–south resolution by a factor of ∼3, but has also enabled fringe detections with signal-to-noise ratios up to 300 at baselines longer than 2 Gλ. The high sensitivity has motivated us to image the data with newly developed regularized maximum likelihood imaging methods, revealing the innermost jet structure with unprecedentedly high angular resolution. Our images reveal a compact and twisted jet extending along the northwest direction, with two bends within the inner 200 μas, resembling a precessing jet in projection. The component at the southeastern end shows a compact morphology and high brightness temperature, and is identified as the VLBI core. An extended jet feature that lies at ∼200 μas northwest of the core shows a conical shape, in both total and linearly polarized intensity, and a bimodal distribution of the linear polarization electric vector position angle. We discuss the nature of this feature by comparing our observations with models and simulations of oblique and recollimation shocks with various magnetic field configurations. Our high-fidelity images also enabled us to search for possible jet features from the secondary supermassive black hole (SMBH) and test the SMBH binary hypothesis proposed for this source.