Compact Morphology Research Articles

Fabrication and characterization of the enhanced tensile strength xanthan/curdlan/gelatin blend films for food-packaging applications

Food packaging films are generally used to protect the food from outside harsh environment. Moreover, their main purpose is to prolong the shelf life and to maintain the freshness of food. Generally, plastic materials are widely used for this purpose. However, these plastic materials are causing a serious threats to our environment due to the problem of non-degradability. In this regard, biodegradable biopolymer materials are contemplated as an important alternative due to the environment friendly characteristics. However, the packaging films prepared from single pure polymers have been reported to possess very poor mechanical properties. Therefore, blending of two or three biopolymers is considered to synergistically improve the mechanical properties of biopolymer based films. In this work, we made a novel blended films of xanthan (X), curdlan (C) and gelatin (G) by mixing different ratios of all three polymers. After successfully preparing and optimization of these blended films, mechanical properties and moisture absorbance properties of all these films were determined. Based on the results, it was concluded that the highest tensile strength of 38.22±0.7 MPa was found in the T2 treatment of 20:20:60 ratio of X/C/G blend films. In addition, highest elongation at break of 18.92±0.5% was also found in the same rational of X/C/G blend films. Moreover, characterization techniques such as FT-IR and SEM analysis were also performed to analyze the structural properties of blend films. Finally, SEM micrographs indicated that all the blend films exhibited a uniform, smooth, homogenous and compact outer surface morphology. In short, this novel xanthan/curdlan/gelatin films resulted in improved mechanical properties of blend films, which confirm its suitability as promising food packaging material.

Enhanced supercapacitive behaviors of poly(3,4-ethylenedioxythiophene)/ graphene oxide hybrids prepared under optimized electropolymerization conditions

Poly(3,4-ethylenedioxythiophene) (PEDOT) is known for compact morphology owing to dense growth, which limits its electrochemical capacitive properties. In this work, we have facilitated the dispersed growth of PEDOT by incorporating graphene oxide (GO) nanosheets, thus forming the PEDOT/GO hybrids via a facile electropolymerization route, in which GO nanosheets act as substrates with large specific area to load PEDOT coatings. The impact of electropolymerization modes and parameters on the supercapacitive properties of PEDOT/GO hybrids is studied in detail. Electrochemical measurements indicate that GO incorporation remarkably enhances the supercapacitive properties of PEDOT electrode. Among numerous preparation conditions, galvanostatically prepared electrode using 1 mA cm−2 presents the optimal supercapacitive properties, delivering an areal capacitance of 109.3 mF cm−2 at 0.5 mA cm−2 and retaining 95.1% of initial capacitance after 10,000 cycles. Such an electrode preserves the curly morphology of GO nanosheets and gives rise to more dispersed distribution for PEDOT coatings.

Electrogalvanization using Zn-graphene oxide composite coatings with enhanced corrosion resistance performance

Zn-based coatings are extensively used for the protection of steel structures. Efforts toward further enhancement in the corrosion resistance performance of Zn coatings are therefore an area of continued interest. In this work, Zn-graphene oxide (Zn-GO) composite coatings containing different volume fractions of GO were electrodeposited on mild steel substrates using an electrolyte bath with different concentrations of dispersed graphene oxide. The electrodeposition parameters used yielded compact and crack-free morphology for all the coatings. Incorporation of GO led to a refinement of the Zn crystallites in the coating matrix. Potentiodynamic polarization measurements clearly showed that all the Zn-GO composite coatings exhibited higher corrosion resistance performance when compared to the pristine Zn coatings, and further, the corrosion rate decreased with the increase in the volume fraction of the GO in the composite coatings.

Microstructural and mechanical characterization of powder-pack boronized Incoloy A286 superalloy

In this study, Incoloy A286 superalloy were boronized successfully by powder-pack boronizing process at 850 °C, 900 °C and 950 °C for 4 h by using a boronizing powder mixture containing H3BO3 as boron source. The thickness and morphology of the boride layer was identified by microstructural examinations. The boride layer with complex, compact and smooth morphology was formed on the surface of the samples. As a result of XRD analyses, it was determined that the compact boride layer was formed many phases such as FeB, Fe2B, Fe3B, CrB and Ni4B3 etc. It was specified that the average hardness value of the boride layer was approximately between 2400 and 3000 HV by microhardness tests. Also the graphs of friction coefficient and values of the specific wear rate were obtained by performing ball on disk wear tests. It was identified that the specific wear rate of boronized samples was approximately 9.5 times lower than that of unboronized samples.

The osteogenic differentiation of human dental pulp stem cells in alginate-gelatin/Nano-hydroxyapatite microcapsules

BackgroundMicrocapsule is considered as a promising 3D microenvironment for Bone Tissue Engineering (BTE) applications. Microencapsulation of cells in an appropriate scaffold not only protected the cells against excess stress but also promoted cell proliferation and differentiation. Through the current study, we aimed to microcapsulate the human Dental Pulp Stem Cells (hDPSCs) and evaluated the proliferation and osteogenic differentiation of those cells by using MTT assay, qRT-PCR, Alkaline phosphatase, and Alizarine Red S.ResultsThe SEM results revealed that Alg/Gel microcapsules containing nHA showed a rough and more compact surface morphology in comparison with the Alg/Gel microcapsules. Moreover, the microencapsulation by Alg/Gel/nHA could improve cell proliferation and induce osteogenic differentiation. The cells cultured in the Alg/Gel and Alg/Gel/nHA microcapsules showed 1.4-fold and 1.7-fold activity of BMP-2 gene expression more in comparison with the control group after 21 days. The mentioned amounts for the BMP-2 gene were 2.5-fold and 4-fold more expression for the Alg/Gel and Alg/Gel/nHA microcapsules after 28 days. The nHA, addition to hDPSCs-laden Alg/Gel microcapsule, could up-regulate the bone-related gene expressions of osteocalcin, osteonectin, and RUNX-2 during the 21 and 28 days through the culturing period, too. Calcium deposition and ALP activities of the cells were observed in accordance with the proliferation results as well as the gene expression analysis.ConclusionThe present study demonstrated that microencapsulation of the hDPSCs inside the Alg/Gel/nHA hydrogel could be a potential approach for regenerative dentistry in the near future.Graphical abstract

Unraveling the effects of blue light in an artificial solar background light on growth of tomato plants

While the use of narrowband irradiance regimes containing different blue light fractions has proven useful to unravel blue light effects on plants at a fundamental level, it does not quantify the responses to blue light under natural daylight conditions. The objective of this study is to understand the blue light growth responses by combining photosynthetic measurements with measurements of whole plant light absorption in a simulated daylight spectrum enriched with different levels of blue light. To achieve this, tomato plants were grown under six different combinations of artificial solar light and blue LED light. Light treatments were defined by the blue light (400–500 nm) fraction of total photosynthetic photon flux density (400–700 nm) and included 27 % (no additional blue LED), 28 %, 31 %, 38 %, 43 % and 61 % blue light with a total photosynthetic photon flux density of 100 μmol m−2 s-1 in all treatments. Whole plant light absorption was estimated by using ray tracing simulation combined with measured 3-dimensional structure of the plant and optical properties of the leaves. The total dry weight of the plants decreased linearly with the increase of blue light fraction; the dry weight of the plants grown under 27 % blue being 1.6 times greater than that of the plants grown under 61 % blue. This large difference was related to lower light absorption by the plants when fraction blue light increased, due to more compact morphology, i.e. lower leaf area, leaf length/width ratio and shorter stem. Light-limited quantum yield and maximum photosynthetic capacity were not affected by blue light fraction. In the case of the latter, which in other studies has often been found to be positively related to blue light fraction, it may be that the blue light fraction already present in the daylight source had saturated this response. Overall, increasing the blue light fraction in a solar light background decreases growth mainly through its effect on plant morphology and light interception. It remains to be elucidated whether the responses observed using the low growth light intensity in the present study are maintained in high light growth environments more characteristic for tomato growth and production.

Effects of γ-C2S on the Properties of Ground Granulated Blast-Furnace Slag Mortar in Natural and Accelerated Carbonation Curing

γ-Dicalcium silicate (γ-C2S) is known for its strong carbonation reactivity by which it can capture atmospheric carbon dioxide (CO2), thus, it can be used in construction industries. This paper aims to study the effects of γ-C2S on the properties of ground granulated blast-furnace slag (GGBFS) containing cement mortar and paste in natural and accelerated carbonation curing. The compressive strength of 5% γ-C2S (G5) added to GGBFS cement mortar is higher compared with the control one in natural carbonation (NC) and accelerated carbonation (AC) up to 14 days of curing, but once the curing duration is increased, there is no significant improvement with the compressive strength observed. The compressive strength of AC-cured mortar samples is higher than that of NC. The scanning electron microscopy (SEM) images show that the AC samples exhibited compact, uniform, and regular morphology with less in porosity than the NC samples. X-ray diffraction (XRD) and Fourier transform infra-red (FT-IR) results confirmed the formation of calcium carbonate (calcite: CC) as carbonated products in paste samples, which make the surface dense and a defect-free matrix result in the highest compressive strength. The decomposition of AC samples around 650–750 °C revealed the well-documented and stable crystalline CC peaks, as observed by thermogravimetry analysis (TGA). This study suggests that γ-C2S added to concrete can capture atmospheric CO2 (mostly generated from cement and metallurgy industries), and make the concrete dense and compact, resulting in improved compressive strength.

Corrosion Behavior of Electrodeposited Nickel Coating Reinforced by Cr<sub>2</sub>O<sub>3</sub> Particles

The objective of this work is the characterisation of the composite deposits Ni-Cr2O3 on copper substrate; these deposits are obtained from bath of electro-deposition of Nickel watts. The different electrodeposited layers are characterized by various analytical techniques such as adhesion quality, corrosion tests, Vickers microhardness, morphology by scanning electron microscopy Followed by EDX microanalysis and X-ray diffraction. The corrosion tests are realized in a solution of 3.5 % NaCl using lost mass method, polarization and impedance spectroscopy techniques. It was found that the composite coatings Ni-Cr2O3 have an homogeneous and compact morphology, well crystallized and exhibit a high degree of codeposition of Cr2O3 particles incorporated in the nickel matrix. The co-deposited films have very good hardness, adhere perfectly to the substrate and are more resistant to corrosion.

Dust Temperature of Compact Star-forming Galaxies at z ∼ 1–3 in 3D-HST/CANDELS

Abstract Recent simulation studies suggest that the compaction of star-forming galaxies (SFGs) at high redshift might be a critical process, during which the central bulge is being rapidly built, followed by quenching of the star formation. To explore dust properties of SFGs with compact morphology, we investigate the dependence of dust temperature, T dust, on their size and star formation activity, using a sample of massive SFGs with at 1 < z < 3, drawn from the 3D-HST/CANDELS database in combination with deep Herschel observations. T dust is derived via fitting the mid-to-far-infrared photometry with a mid-infrared power law and a far-infrared modified blackbody. We find that both extended and compact SFGs generally follow a similar T dust − z evolutionary track as that of the main-sequence galaxies. The compact SFGs seem to share similar dust temperature with extended SFGs. Despite the frequent occurrence of active galactic nuclei (AGNs) in compact SFGs, we do not observe any effect on dust caused by the presence of AGNs in these galaxies during the compaction. Our results disfavor different ISM properties between compact and extended SFGs, suggesting that a rapid and violent compaction process might be not necessary for the formation of compact SFGs.

Interface and bulk controlled perovskite nanocrystal growth for high brightness light-emitting diodes [Invited

Halide perovskites have attracted great attention due to their high color purity, high luminance yield, low non-radiative recombination rate, and solution processability. Although the external quantum efficiency of perovskite light-emitting diodes (PeLEDs) is comparable with that of the organic light-emitting diodes (OLEDs) and quantum-dots light-emitting diodes (QLEDs), the brightness is still low compared with the traditional OLEDs and QLEDs. Herein, we demonstrate high brightness and high-efficiency CsPbBr3-based PeLEDs using interface and bulk controlled nanocrystal growth of the perovskite emission layer. The interface engineering by ethanolamine and bulk engineering by polyethylene glycol led to highly crystallized and cubic-shaped perovskite nanocrystals with smooth and compact morphology. As a result, PeLEDs with a high brightness of 64756 cd/m2 and an external quantum efficiency of 13.4% have been achieved.

Endowing magnesium with the corrosion-resistance property through cross-linking polymerized inorganic sol-gel coating.

The design of a highly adhesive, defect-free and low-temperature sol–gel coating for the protection of magnesium alloys is desirable yet challenging. In this study, a novel SiO2-based sol–gel coating is developed by a ring-opening addition reaction. Notably, the integration of individual sol clusters endows the sol–gel coating with a smooth and compact surface morphology, and eliminates the potential corrosion site of the low-temperature-prepared sol–gel coating. Besides, the as-obtained sol–gel coating exhibits excellent metallic adhesion nature. Most importantly, it increases the overall impedance modulus by 27 times than that of the conventional strategy and decreases the corrosion rate from 3.8 ± 0.5 mg cm−2 per day (commercial chromate conversion coating) to 0.5 ± 0.2 mg cm−2 per day.

Luminescence sensitization of terbium-loaded supramolecular gels by hydroxybenzoic acids and used for salicylates sensing

The luminescent terbium (Tb3+)-loaded supramolecular gels were facilely prepared through the self-assembly of Fmoc-diphenylalanine (FmocPhePhe) at room temperature. Hydroxybenzoic acid (HA, the isomers are denoted as 2-HA, 3-HA, and 4-HA depending upon the positions of hydroxyl groups) was used as a sensitizer to Tb3+. The luminescence sensitization of Tb3+ in the gels was realized by the coordination with hydroxybenzoic acids. The spectra of luminescence, UV–vis, FT-IR, and 1H NMR verified that this sensitization was attributed to the energy transfer from hydroxybenzoic acids to Tb3+. The results of XRD, SEM, and phase transfer temperature further indicated that the initial molecule arrangement of the gels was significantly changed by 2-HA, resulting in more ordered and more compact morphology of the gels. 2-HA exhibited more effective sensitization to Tb3+ in the gels than 3-HA and 4-HA. It was also found that 2-HA did not affect the self-assembly of FmocPhePhe. Due to the effective fluorescence sensitization by 2-HA, the as-prepared gels can be used for salicylic acid sensing with 6.8 μM of the detection limit. This strategy has been successfully used for the detection of salicylates in pharmaceuticals and cosmetics.

Recent advances in cochlear hair cell nanophysiology: subcellular compartmentalization of electrical signaling in compact sensory cells.

In recent years, genetics, physiology, and structural biology have advanced into the molecular details of the sensory physiology of auditory hair cells. Inner hair cells (IHCs) and outer hair cells (OHCs) mediate two key functions: active amplification and non-linear compression of cochlear vibrations by OHCs and sound encoding by IHCs at their afferent synapses with the spiral ganglion neurons. OHCs and IHCs share some molecular physiology, e.g. mechanotransduction at the apical hair bundles, ribbon-type presynaptic active zones, and ionic conductances in the basolateral membrane. Unique features enabling their specific function include prestin-based electromotility of OHCs and indefatigable transmitter release at the highest known rates by ribbon-type IHC active zones. Despite their compact morphology, the molecular machineries that either generate electrical signals or are driven by these signals are essentially all segregated into local subcellular structures. This review provides a brief account on recent insights into the molecular physiology of cochlear hair cells with a specific focus on organization into membrane domains.

Accretion and outflow activity in proto-brown dwarfs

Abstract We present a near-infrared study of accretion and outflow activity in 6 Class 0/I proto-brown dwarfs (proto-BDs) using VLT/SINFONI spectroscopy and spectro-imaging observations. The spectra show emission in several [Fe II] and H2 lines associated with jet/outflow activity, and in the accretion diagnostics of Pa β and Br γ lines. The peak velocities of the [Fe II] lines (>100 km s−1) are higher than the H2 lines. The Class 0 proto-BDs show strong emission in the H2 lines but the [Fe II] lines are undetected, while the Class I objects show emission in both [Fe II] and H2 lines, suggesting an evolutionary trend in the jets from a molecular to an ionic composition. Extended emission with knots is seen in the [Fe II] and H2 spectro-images for 3 proto-BDs, while the rest show compact morphologies with a peak on-source. The accretion rates for the proto-BDs span the range of (2× 10−6 – 2× 10−8) M⊙ yr−1, while the mass loss rates are in the range of (4× 10−8 – 5× 10−9) M⊙ yr−1. These rates are within the range measured for low-mass protostars and higher than Class II brown dwarfs. We find a similar range in the jet efficiency for proto-BDs as measured in protostars. We have performed a study of the Brackett decrement from the Br 7-19 lines detected in the proto-BDs. The upper Brackett lines of Br 13–19 are only detected in the earlier stage systems. The ratios of the different Brackett lines with respect to the Brγ line intensity are consistent with the ratios expected from Case B recombination.

Transient Receptor Potential Vanilloid 6 (TRPV6) Proteins Control the Extracellular Matrix Structure of the Placental Labyrinth.

Calcium-selective transient receptor potential Vanilloid 6 (TRPV6) channels are expressed in fetal labyrinth trophoblasts as part of the feto–maternal barrier, necessary for sufficient calcium supply, embryo growth, and bone development during pregnancy. Recently, we have shown a less- compact labyrinth morphology of Trpv6-deficient placentae, and reduced Ca2+ uptake of primary trophoblasts upon functional deletion of TRPV6. Trpv6-/- trophoblasts show a distinct calcium-dependent phenotype. Deep proteomic profiling of wt and Trpv6-/- primary trophoblasts using label-free quantitative mass spectrometry leads to the identification of 2778 proteins. Among those, a group of proteases, including high-temperature requirement A serine peptidase 1 (HTRA1) and different granzymes are more abundantly expressed in Trpv6-/- trophoblast lysates, whereas the extracellular matrix protein fibronectin and the fibronectin-domain-containing protein 3A (FND3A) were markedly reduced. Trpv6-/- placenta lysates contain a higher intrinsic proteolytic activity increasing fibronectin degradation. Our results show that the extracellular matrix formation of the placental labyrinth depends on TRPV6; its deletion in trophoblasts correlates with the increased expression of proteases controlling the extracellular matrix in the labyrinth during pregnancy.

Electromagnetic Shielding Performance of Different Metallic Coatings Deposited by Arc Thermal Spray Process.

Advancement in electronic and communication technologies bring us up to date, but it causes electromagnetic interference (EMI) resulting in failure of building and infrastructure, hospital, military base, nuclear plant, and sensitive electronics. Therefore, it is of the utmost importance to prevent the failure of structures and electronic components from EMI using conducting coating. In the present study, Cu, Cu-Zn, and Cu-Ni coating was deposited in different thicknesses and their morphology, composition, conductivity, and EMI shielding effectiveness are assessed. The scanning electron microscopy (SEM) results show that 100 µm coating possesses severe defects and porosity but once the thickness is increased to 500 µm, the porosity and electrical conductivity is gradually decreased and increased, respectively. Cu-Zn coating exhibited lowest in porosity, dense, and compact morphology. As the thickness of coating is increased, the EMI shielding effectiveness is increased. Moreover, 100 µm Cu-Zn coating shows 80 dB EMI shielding effectiveness at 1 GHz but Cu and Cu-Ni are found to be 68 and 12 dB, respectively. EMI shielding effectiveness results reveal that 100 µm Cu-Zn coating satisfy the minimum requirement for EMI shielding while Cu and Cu-Ni required higher thickness.

Developing of thermal energy storing visual textile temperature indicators based on reversible color change

The aim of this study was to fabricate cotton and wool fabrics with both of thermoregulation and thermochromic properties. For this aim, three-component thermochromic systems (TCTS) were microencapsulated and applied to the pure cotton and wool textile fabrics. In the study, TCTSs consisting of crystal violet lactone (CVL), bisphenol A (BPA), and myristyl alcohol were microencapsulated in shell of poly(methyl methacrylate-co-methacrylic acid) (P(MMA-co-MAA)) by emulsion polymerization method. Microcapsule wall structures were designed to exhibit affinity for cotton and wool fibres under appropriate reaction conditions. Microcapsules having spherical shape, compact morphology and average size of 23.24 µm were prepared successfully. These microparticles exhibited latent heat energy storage capacity of 197.7 J/g and considerable thermal stability required for textile application process conditions. P(MMA-co-MAA)/TCTS microcapsules were applied to the cotton and wool textiles by exhaustion method. In the method, a substrate takes the chemicals in the bath and the affinity between the chemicals and substrate molecules is determinant on exhaustion process. The structural, colorimetric and thermal characteristics of the microcapsule applied fabrics were analyzed. The fabrics had reversible color change with a function of temperature. Their colors were blue at room temperature and original color of the fabric at temperatures above activation point of the thermochromic system. Additionally, the cotton fabric stored the latent heat of 23.4 J/g while the wool fabric stored the latent heat of 62.1 J/g. They exhibited thermoregulation property resulting from the absorbed latent heat.

Sb2S3 Seed-Mediated Growth of Low-Defect Sb2S3 on a TiO2 Substrate for Efficient Solar Cells

Hydrothermal deposition was recently developed to prepare an antimony selenosulfide thin film with large grain size and flat and compact surface morphology, leading to efficient breakthrough in sol...

In Vitro Induction of Pluripotency from Equine Fibroblasts in 20% or 5% Oxygen.

The cellular reprogramming into pluripotency is influenced by external and internal cellular factors, such as in vitro culture conditions (e.g., environmental oxygen concentration), and the aging process. Herein, we aimed to generate and maintain equine iPSCs (eiPSCs) derived from fibroblasts of a horse older than 20 years and to evaluate the effect of different levels of oxygen tension (atmospheric 20% O2, 5% O2, or 20% to 5% O2) on these cells. Fibroblasts were reprogrammed, and putative eiPSCs were positive for positive alkaline phosphatase detection; they were positive for pluripotency-related genes OCT4, REX1, and NANOG; immunofluorescence-positive staining was presented for OCT4 and NANOG (all groups), SOX2 (groups 5% O2 and 20% to 5% O2), and TRA-1-60, TRA-1-81, and SSEA-1 (only in 20% O2); they formed embryoid bodies; and there is spontaneous differentiation in mesoderm, endoderm, and ectoderm embryonic germ layers. In addition to the differences in immunofluorescence analysis results, the eiPSC colonies generated at 20% O2 presented a more compact morphology with a well-defined border than cells cultured in 5% O2 and 20% to 5% O2. Significant differences were also observed in the expression of genes related to glucose metabolism, mitochondrial fission, and hypoxia (GAPDH, GLUT3, MFN1, HIF1α, and HIF2α), after reprogramming. Our results show that the derivation of eiPSCs was not impaired by aging. Additionally, this study is the first to compare high and low oxygen cultures of eiPSCs, showing the generation of pluripotent cells with different profiles. Under the tested conditions, the lower oxygen tension did not favor the pluripotency of eiPSCs. This study shows that the impact of oxygen atmosphere has to be considered when culturing eiPSCs, as this condition influences the pluripotency characteristics.

Co2+ Substituted Spinel MgCuZn Ferrimagnetic Oxide: A Highly Versatile Electromagnetic Material via a Facile Molten Salt Route

We report on the electromagnetic properties of Co2+ substituted spinel MgCuZn ferrites developed via a facile molten salt synthesis (MSS) route. The choice of synthesis route in combination with cobalt substitution led to strong electromagnetic properties such as high saturation magnetization (i.e., 63 emu/g), high coercivity (17.86 gauss), and high initial permeability (2730), which are beneficial for the multilayer chip inductor (MLCI) application. In a typical process, the planned ferrites were synthesized at 800 °C using sodium chloride as a growth inhibitor, with dense morphology and irregularity in the monolithicity of the grains. The compositional analysis of as-prepared ferrite confirms the presence of desired elements with their proportion. The crystallite size (using X-ray diffraction (XRD) analysis) for different samples varies in the range of 49–51 nm. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showcases the compact morphology of the developed samples, which is typical in the ferrite system. The dielectric properties (dielectric-loss and dielectric-constant) in the frequency range of 100Hz–1MHz suggest normal dielectric distribution according to interfacial polarization from Maxwell–Wagner. From the developed ferrites, upon comparison with a low dielectric loss with high permeability value, Mg-Cu-Zn ferrite with Co = 0.05 substitution proved to be a stronger material for MLCIs with high-performance applications.