Effect of Tween-80 on the Control of Particle Size and Shrinkage Properties of Nanoscale α-Alumina Synthesized by Sol–Gel Processing

The concept of tailored interfaces has been applied to the synthesis of nanoscale α-Al₂O₃. Tween-80 (poly-oxyethylene(20) sorbitan monooleate, T-80) was used as a surface modifier in the sol–gel process for this purpose. High-resolution transmission electron microscopy study of the powder obtained with T-80 confirmed the particle size of α-Al₂O₃ (∼55 nm) and morphology (spherical). The exothermic peak temperature in the differential thermal analysis was shifted to a lower temperature (∼917°C) when the powder was derived from a T-80 modifier content of 10 wt%. X-ray diffraction showed that the α-Al₂O₃ phase was the major phase that existed in modifier-derived powder that was sintered at 1000°C. The experiments, based on linear shrinkage, indicated that the powder with T-80 (10 wt%) could be densified at a low temperature.     

γ-Tocotrienol as a Promising Countermeasure for Acute Radiation Syndrome: Current Status

The hazard of ionizing radiation exposure due to nuclear accidents or terrorist attacks is ever increasing. Despite decades of research, still, there is a shortage of non-toxic, safe and effective medical countermeasures for radiological and nuclear emergency. To date, the U.S. Food and Drug Administration (U.S. FDA) has approved only two growth factors, Neupogen (granulocyte colony-stimulating factor (G-CSF), filgrastim) and Neulasta (PEGylated G-CSF, pegfilgrastim) for the treatment of hematopoietic acute radiation syndrome (H-ARS) following the Animal Efficacy Rule. Promising radioprotective efficacy results of γ-tocotrienol (GT3; a member of the vitamin E family) in the mouse model encouraged its further evaluation in the nonhuman primate (NHP) model. These studies demonstrated that GT3 significantly aided the recovery of radiation-induced neutropenia and thrombocytopenia compared to the vehicle controls; these results particularly significant after exposure to 5.8 or 6.5 Gray (Gy) whole body γ-irradiation. The stimulatory effect of GT3 on neutrophils and thrombocytes (platelets) was directly and positively correlated with dose; a 75 mg/kg dose was more effective compared to 37.5 mg/kg. GT3 was also effective against 6.5 Gy whole body γ-irradiation for improving neutrophils and thrombocytes. Moreover, a single administration of GT3 without any supportive care was equivalent, in terms of improving hematopoietic recovery, to multiple doses of Neupogen and two doses of Neulasta with full supportive care (including blood products) in the NHP model. GT3 may serve as an ultimate radioprotector for use in humans, particularly for military personnel and first responders. In brief, GT3 is a promising radiation countermeasure that ought to be further developed for U.S. FDA approval for the ARS indication.     

Waste Eggshell-Derived Calcium Oxide and Nanohydroxyapatite Biomaterials for the Preparation of LLDPE Polymer Nanocomposite and Their Thermomechanical Study

Waste eggshells were utilized to make calcium oxide (E-CaO) and hydroxyapatite (E-HAP). E-CaO obtained by heat treatment to eggshells was utilized for the synthesis of E-HAP. Melt compounding of E-CaO/E-HAP was performed with linear low-density polyethylene (LLDPE) on a Brabender Plastograph and ground the obtained formulation for injection molding. Addition of E-CaO/E-HAP in the LLDPE significantly enhanced the flame retardant ability and thermal stability of resultant composites. In the comparative study, E-HAP nanopowder-containing polymer composite showed increment in thermal and mechanical properties than the composite prepared using E-CaO.     

Analysis of the Quaternary Structure of Hemoglobin Beckman Variant and Molecular Interpretation of Its Functional Abnormality: A Mass‐Spectrometry‐Based Approach

Electrostatic attraction between α and β globin chains holds the subunits together in a tetrameric human hemoglobin molecule (α₂β₂). Compared to normal globin chains, the affinity of a mutant chain to its partner globin might be different in genetic variants of hemoglobin. This leads to an unequal abundance of normal and variant hemoglobin in heterozygous samples, even though the rates of synthesis of both the normal and variant chains are the same. The aforementioned affinities across various globin chains might be assessed by quantification of the different forms of the tetramers present in a variant hemoglobin sample. In the present study, by exploiting mass differences between globin chains, differently populated hemoglobin tetramers present in hemoglobin (Hb) Beckman, a β variant (βA135D), were structurally characterized. The relative populations of dissymmetric tetramers (α₂β₂, α₂ββ^V, and α₂β^V₂) indicated that both β and β^V have different affinities towards the α globin chain. Conformational dynamics analyzed from hydrogen/deuterium exchange kinetics of the three peptide fragments of Hb Beckman in its oxy state displayed molecular insight into its functional abnormality. However, in comparison to normal hemoglobin (α₂β₂), the point mutation did not show any change in the collision cross‐sections of the functionally active conformers of the variant hemoglobin molecules (α₂ββ^V and α₂β^V₂).     

Carbon Doping in Boron Suboxide: Structure,Energetics, and Elastic Properties

The structural, electronic, and elastic properties of pristine and carbon‐doped boron suboxide (B₆O) are calculated using density functional theory. The results indicate that it is energetically preferable for a single carbon atom to substitute into an oxygen site rather than a boron site. The lattice parameters and cell volume increase to relieve the residual stress created by the carbon substitution. The interstitial position is not favorable for a single atom substitution. However, if two carbon atoms substitute for two neighboring oxygen atoms, then it becomes energetically favorable to dope an interstitial oxygen, boron, or carbon atom along the C–C chain. If the interstitial dopant is either boron or carbon, a local B₄C‐like structure with either a C–B–C or C–C–C chain is created within the boron suboxide unit cell. The resulting structure shows improvements in the bulk modulus at the expense of the shear and Young's moduli. The moduli further improve if an additional carbon is substituted within a polar or equatorial site of the neighboring B₁₂ icosahedron. Based on these calculations, we conclude that carbon doping can either harden or soften B₆O depending on the manner in which the substitutions are populated. Furthermore, as B₆O samples are often oxygen deficient, C doping can occupy such sites and improve the elastic properties.     

A Novel Highly Sensitive Humidity Sensor Based on ZnO/SBA‐15 Hybrid Nanocomposite

This work deals with the study of hydrothermally synthesized zinc oxide (ZnO) loaded mesoporous SBA‐15 hybrid nanocomposite for relative humidity sensing (RH) at room temperature. The sensor exhibits an excellent ~5 orders impedance change along with excellent linearity, quick response time (17 s), rapid recovery time (18 s), negligible hysteresis (1.2%), good repeatability, and stability (1.8%) in 11%–98% RH range. In addition, complex impedance spectra of the sensor at different RHs were analyzed to understand the humidity sensing mechanism. Our study can open a new way for realizing ZnO/SBA‐15 hybrid nanocomposite for fabrication of high‐performance RH sensors.     

Cross-thickness vibration welding of polycarbonate,polyetherimide, poly(butylene terephthalate), and modified polyphenylene oxide

In vibration welding of thermoplastics, frictional heat generated by vibrating two parts under pressure, along their common interface, is used to effect welds. In the normal, well-understood mode, the vibratory motion is along the weld seam, which is at right angles to the thickness direction for straight boundaries. But in many applications, such as in the welding of closed seams of box-like parts, this vibratory motion occurs in the part-thickness direction, so that a portion of the molten layer along the seam is exposed to the ambient air during each vibratory cycle. The resulting reduction in temperature can affect weld quality. The process phenomenology and the weld strengths of such cross-thickness vibration-welded butt joints are investigated for four neat resins. Weld amplitudes and weld pressures are shown to affect the strengths of 120-Hz welds differently. It is shown that strengths on the order of the strengths of the neat resins can be achieved in 250-Hz butt welds.     

Ionic‐liquid‐assisted three‐dimensional caged silica ablative nanocomposites

In this study, we demonstrated a novel three‐dimensional network of thermally stable fumed silica (FS)–resorcinol formaldehyde (RF) nanocomposites via an ionic‐liquid (IL)‐assisted in situ polycondensation process. The study involved subjecting the tailored nanocomposites to thermogravimetric analysis and oxyacetylene flame environment as per ASTM test standards for thermal ablative performance. X‐ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high‐resolution transmission electron microscopy, Raman spectroscopy, and wettability studies were undertaken to underline the improvement correlation in the microstructure and material properties. Significant reductions in the linear ablation rate (66%) and mass ablation rate (26.6%), along with lower back‐face temperature profiles, marked enhanced ablative properties. The increased char yield (33.3%) and higher temperatures for weight losses evinced the improved thermal stability of the modified RF resin. The uniformly dispersed fused nanosilica with a glassy coating morphology on the ablative surface acted as barrier to oxidation. The results signify that the IL‐assisted modification of the RF resin with FS significantly enhanced ablative performance. A viable replacement to the conventional phenolic nanocomposites for thermal ablative applications to buy critical time for the containment and suppression of thermal‐heat‐flux threats is of paramount importance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45328.     

Lipoxygenase and Tocopherol Profiling of Soybean Genotypes Exposed to Electron Beam Irradiation

Electron beam (EB)-irradiation is increasingly being preferred to radioactive-based gamma irradiation in overcoming the constraints that affect the quality of food material. Soybean seeds of 3 soybean genotypes were exposed to 4 doses viz. 4.8, 9.2, 15.3 and 21.2 kGy of EB-irradiation and assessed for the changes in the contents of lipoxygenase isozymes and tocopherol isomers. Densitometry of protein profile revealed decreasing intensity of lipoxygenase with increasing EB dose. All the 3 lipoxygenase isozymes viz. lipoxygenase-1, -2 and -3 registered significant (P < 0.05) increasing reduction with increasing dose; though genotypic variation was noted for the magnitude of reduction at the same dose. Concomitantly, all the 3 genotypes exhibited significant (P < 0.05) decline in α-, γ- and δ-isomers of tocopherol. δ-Tocopherol was the most sensitive to EB-irradiation. EB dose, which caused minimum and maximum decline in total tocopherol content, was genotype-dependent. Decline in vitamin E activity corresponding to the dose, which induced maximum reduction for total lipoxygenase also varied in 3 genotypes. The study showed the usefulness of EB for significant inactivation of off-flavor generating lipoxygenases in soybean, with a non-significant effect on oil content and varied retention of tocopherol isomers and vitamin E activity depending upon genotype.     

Sono-Fenton regeneration of granular activated carbon saturated with Rhodamine B: Optimization using response surface methodology

This study investigated the combination of chemical and ultrasonic regeneration (Sono-Fenton), used for regenerating granular activated carbon (GAC) saturated with Rhodamine B (RB). This process was modeled and optimized using response surface methodology (RSM) based on central composite design (CCD). Effective parameters on regeneration efficiency such as pH, concentration of hydrogen peroxide (H₂O₂), and time of ultrasonic irradiation were optimized and modeled using the reduced quadratic method. The fitness of the model was checked by the determination coefficient (R²?=?0.9978). At optimum condition, the effective parameters of pH?=?3.84, concentration of H₂O₂?=?38.28 (mM), and time of ultrasonic irradiation?=?23.11(min), maximum regeneration efficiency (87.88%) was achieved, the results of which were obtained after four-time sequential adsorption–regeneration cycles were acceptable. Desorption and degradation of RB were conducted through the generation of active species, including hydroxyl radicals and high-energy ultrasound. The regeneration efficiency was increased using this combination method. In conclusion, the Sono-Fenton method is suggested to be used more widely in regeneration processes.