Recent Advances in Microalgal Bioactives for Food,Feed, and Healthcare Products: Commercial Potential,Market Space,and Sustainability

To combat food scarcity as well as to ensure nutritional food supply for sustainable living of increasing population, microalgae are considered as innovative sources for adequate nutrition. Currently, the dried biomass, various carotenoids, phycocyanin, phycoerythrin, omega fatty acids, and enzymes are being used as food additives, food coloring agents, and food supplements. Apart from nutritional importance, microalgae are finding the place in the market as “functional foods.” When compared to the total market size of food and feed products derived from all the possible sources, the market portfolio of microalgae‐based products is still smaller, but increasing steadily. On the other hand, the genetic modification of microalgae for enhanced production of commercially important metabolites holds a great potential. However, the success of commercial application of genetically modified (GM) algae will be defined by their safety to human health and environment. In view of this, the present study attempts to highlight the industrially important microalgal metabolites, their production, and application in food, feed, nutraceuticals, pharmaceuticals, and cosmeceuticals. The current and future market trends for microalgal products have been thoroughly discussed. Importantly, the safety pertaining to microalgae cultivation and consumption, and regulatory issues for GM microalgae have also been covered.     

Erratum to: Fe Oxides on Ag Surfaces: Structure and Reactivity

Topics in Catalysis -     

Dual gas sensing properties of graphene-Pd/SnO2 composites for H2 and ethanol: Role of nanoparticles-graphene interface

In the present work, role of palladium (Pd) and tin oxide (SnO₂) nanoparticles (NPs) deposited on graphene has been investigated in terms of dual gas sensing characteristics of ethanol and H₂ between two temperatures. The incorporation of nanoparticles into graphene has been observed which results a large change in the sensing response towards these gases. It is investigated that, incorporation of isolated Pd NPs on the graphene facilitates the room temperature sensing of H₂ gas with fast response and recovery time whereas, isolated SnO₂ NPs on graphene enables the detection of ethanol at 200 °C. However, combination of isolated Pd and SnO₂ NPs on graphene shows improved sensitivity and good selectivity towards H₂ and ethanol, usually not observed in chemiresistive gas sensors. Catalytic PdH interaction and corresponding change in work function of nanoparticles on hydrogenation resulting in modifications in electronic exchange between Pd, SnO₂ and graphene are responsible for the observed behavior. These results are important for developing a new class of chemiresistive type gas sensor based on change in the electronic properties of the graphene and NPs interfaces.     

Nonlinear thermoelastic frequency analysis of functionally graded CNT-reinforced single/doubly curved shallow shell panels by FEM

In this article, the nonlinear vibration frequencies of functionally graded carbon nanotube-reinforced composite doubly curved shell panels under elevated thermal environment are numerically investigated using finite element method. The doubly curved carbon nanotube-reinforced shell panel has been modeled mathematically using higher-order kinematics theory and Green–Lagrange geometrical nonlinear strains. The properties of the individual constituents of the graded composite are assumed to be temperature dependent. In addition, the properties of the media are obtained based on the modified rule of mixture. The carbon nanotubes are dispersed nonuniformly through the thickness direction. The large deformation kinematic effects on the structural responses are counted by including all the nonlinear higher-order terms in the formulation. The desired nonlinear responses are computed numerically using our in-house computer code in conjunction with the direct iterative scheme. The convergence and the accuracy of the present numerical model have been checked by solving various numerical examples. Nonlinear mechanical responses were affected by several other design parameters and explored numerically for the thickness ratios, volume fractions, temperature loading, type of geometries, and type of grading under the uniform thermal environment.     

Thiophene-based molecular and polymeric semiconductors for organic field effect transistors and organic thin film transistors

Organic electronics has been a popular field for the last two decades, due to its potential to commercialize cheap-price and large-area flexible electronics. The devices based on organic compounds heavily rely on organic semiconductors (OSs). Primary challenge for materials chemist is the new OSs construction that has ameliorated attainment in organic thin film transistors (OTFTs) and organic field effect transistors (OFETs). The construction of air-stable (stable in air) n-channel OSs (electron-conducting materials) is particularly needed with capability comparable to that of p-channel materials (hole-conducting materials). In the last 10 years, there have been significant advancements in thiophene-based OSs. Thiophene-mediated molecules have a prominent role in the advancement of OSs. The main significance in thiophene-based molecules is their cheap-price (in comparison to silicon), processability at low temperature, structural flexibility, ability to be applied on flexible substrates, and high charge transport characteristics. In this paper, we review the progress in the performance of thiophene-based OSs that has been reported in the last 18 years, with a major emphasis on the last 10 years. This approach provides a crisp introduction to organic devices and catalogs progress toward the fabrication of thiophene containing p, n and ambipolar channel OSs, and discusses their characteristics. Finally, review discusses current challenges and future research directions for thiophene based OSs. This review would be beneficial for further developments in the technological performance. Moreover, this review will serve to accelerate knowledge and lays the foundation for improved applications. Hopefully, this struggle pushes the reader’s mind to consider new perspectives, think differently and forge new connections.     

Numerical Study of Frequency and Deflection Responses of Natural Fiber (Luffa) Reinforced Polymer Composite and Experimental Validation

ABSTRACT

The natural fiber (Luffa cylindrica fiber) reinforced epoxy composite has been fabricated and their structural responses (frequency and deflection) have been computed experimentally and numerically first time using the corresponding experimental elastic properties. The numerical responses are obtained with the help of an in-house MATLAB code developed based on the higher order finite element (FE) model. The completeness of the model has been examined by comparing the current FE solutions (frequency and the central deflection) with the reference as well as in-house experimental data. The effect of fiber volume fractions on the elastic properties is verified for four different weight percentage of treated Luffa fiber (0%, 3.2%, 6.4%, and 9.6%). Finally, the inclusive behavior of the current higher order FE model and the corresponding influence of the significant design parameter of Luffa fiber-reinforced composite structure have been debated by solving different numerical examples.     

The modification of titanium in mesoporous silica for Co-based Fischer–Tropsch catalysts

Ordered SBA-15 mesoporous silica with incorporated titanium was successfully synthesized via a one-pot hydrothermal crystallization method. The characterization including powder X-ray diffraction, Brunauer–Emmett–Teller, transmission electron microscope, temperature-programmed reduction, temperature-programmed desorption, Fourier transform infrared and ultraviolet-visible-near infrared spectrometer was performed to explore the physical and chemical structures of both the supports and the catalysts. The results showed that titanium was successfully incorporated into the mesoporous silica framework with a limited amount of titanium (Si/Ti > 20), and the mesoporous structure was retained. However, the increased titanium content inevitably resulted in the formation of anatase TiO ₂ particles on the support surface. The increased incorporated titanium strengthened the interactions between cobalt species and supports, which was favorable for the cobalt species dispersion, despite the limited cobalt oxide reducibility. The enhanced metal-support interactions were beneficial for the CO/H₂ ratio at the active cobalt sites, which facilitated the formation of more C₅₊ hydrocarbons. This study provides a promising method for support modification with incorporated-heteroatoms for the rational development of Fischer–Tropsch catalysts.     

Exogenously-Sourced Ethylene Positively Modulates Photosynthesis,Carbohydrate Metabolism,and Antioxidant Defense to Enhance Heat Tolerance in Rice

The effect of exogenously-applied ethylene sourced from ethephon (2-chloroethyl phosphonic acid)was studied on photosynthesis, carbohydrate metabolism, and high-temperature stress tolerance in Taipei-309 and Rasi cultivars of rice (Oryza sativa L.). Heat stress increased the content of H₂O₂ and thiobarbituric acid reactive substances (TBARS)more in Rasi than Taipei-309. Further, a significant decline in sucrose, starch, and carbohydrate metabolism enzyme activity and photosynthesis was also observed in response to heat stress. The application of ethephon reduced H₂O₂ and TBARS content by enhancing the enzymatic antioxidant defense system and improved carbohydrate metabolism, photosynthesis, and growth more conspicuously in Taipei-309 under heat stress. The ethephon application enhanced photosynthesis by up-regulating the psbA and psbB genes of photosystem II in heat-stressed plants. Interestingly, foliar application of ethephoneffectively down-regulated high-temperature-stress-induced elevated ethylene biosynthesis gene expression. Overall, ethephon application optimized ethylene levels under high-temperature stress to regulate the antioxidant enzymatic system and carbohydrate metabolism, reducing the adverse effects on photosynthesis. These findings suggest that ethylene regulates photosynthesis via carbohydrate metabolism and the antioxidant system, thereby influencing high-temperature stress tolerance in rice.     

How do polyunsaturated fatty acids lower plasma cholesterol levels?

For 30 years it has been known that linoleic acid can lower elevated cholesterol levels. Large increases in linoleic acid have been widely recommended as a way of reducing the risk of cardiovascular disease. Such recommendations have resulted in major dietary shifts in some countries, including the USA. Yet the precise characteristics of the linoleic acid molecule which confer on it cholesterol-lowering properties are unknown. gamma-Linolenic acid, the first essential fatty acid metabolite of linoleic acid, has been found to have cholesterol-lowering actions ca. 170 times greater than the parent molecule, suggesting that linoleic acid must be converted to gamma-linolenic acid to exert its desirable effects on cholesterol metabolism. Aging, sex, diabetes mellitus, alcohol, catecholamines and trans fatty acids and saturated fats can all modulate the delta-6-desaturase enzyme which converts linoleic acid to gamma-linolenic acid. This provides a possible unifying explanation for the actions of these known risk factors for cardiovascular disease.