The use of magnetic nanoparticles as a solid support material for the development of magnetically retrievable catalytic systems has led to a dramatic expansion of their potential applications as they ...enable environmentally-friendly and sustainable catalytic processes. These quasi-homogeneous catalysts possess numerous benefits such as ease of isolation and separation from the desired reaction mixtures using an external magnet and excellent recyclability. Consequently, much effort has been directed towards the synthesis of magnetically isolable nano-sized particles by developing methods such as co-precipitation, thermal decomposition, microemulsion, hydrothermal techniques
etc
. Further, in order to render them suitable for catalytic applications, several protection strategies such as surfactant/polymer, silica and carbon coating of magnetic nanoparticles or embedding them in a matrix/support have been reported in the literature. This review focuses on the substantial progress made in the fabrication of nanostructured catalysts with special emphasis on the protection and functionalization of the magnetite nanoparticles (Fe
3
O
4
). Finally, considering the importance of coupling chemistry in the field of organic synthesis, a broad overview of the applications of these magnetite nanoparticle-based catalysts in several types of coupling reactions has been presented. The future of catalysis lies in the rational design and development of novel, highly active and recyclable nanocomposite catalysts which would eventually pave the pathway for the establishment of green and sustainable technologies.
Fabrication of functionalized magnetite nanocomposites and their applications as catalysts for coupling reactions.
Stem Cell Research and Tissue Engineering, in present time, have emerged as a legalized and regulated stem cell treatment option globally, but scientifically, their success is unestablished. Novel ...stem cell-based therapies have evolved as innovative and routine clinical solutions by commercial companies and hospitals across the world. Such rampant spread of stem cell clinics throughout UK, US, Europe and Asia reflect the public encouragement of benefits to incurable diseases. However, ever growing stem cell therapy developments need constant dogwatch and careful policy making by government regulatory bodies for prompt action in case of any untoward public concern. Therefore, researchers and physicians must keep themselves abreast of current knowledge on stem cells, tissue engineering devices in treatment and its safe legal limits. With this aim, stem cell scienctific developments, treatment options and legal scenario are introduced here to beginner or actively inolved scientists and physicians. Introduction to stem cell therapy will provide basic information to beginner researchers and practice physicians on engineered stem cell research concepts and present stem cell therapy federal regulations in different North American, European and Asian countries. FDA, CDC, EU, ICMR government policies in different countries include information on the current legal position, ethical policies, regulatory oversight and relevant laws.
The surging demand for energy and staggering pollutants in the environment have geared the scientific community to explore sustainable pathways that are economically feasible and environmentally ...compelling. In this context, harnessing solar energy using semiconductor materials to generate charge pairs to drive photoredox reactions has been envisioned as a futuristic approach. Numerous inorganic crystals with promising nanoregime properties investigated in the past decade have yet to demonstrate practical application due to limited photon absorption and sluggish charge separation kinetics. Two-dimensional semiconductors with tunable optical and electronic properties and quasi-resistance-free lateral charge transfer mechanisms have shown great promise in photocatalysis. Polymeric graphitic carbon nitride (g-C3N4) is among the most promising candidates due to fine-tuned band edges and the feasibility of optimizing the optical properties via materials genomics. Constructing a two-dimensional (2D)/2D van der Waals (vdW) heterojunction by allies of 2D carbon nitride sheets and other 2D semiconductors has demonstrated enhanced charge separation with improved visible photon absorption, and the performance is not restricted by the lattice matching of constituting materials. With the advent of new 2D semiconductors over the recent past, the 2D/2D heterojunction assemblies are gaining momentum to design high performance photocatalysts for numerous applications. This review aims to highlight recent advancements and key understanding in carbon nitride based 2D/2D heterojunctions and their applications in photocatalysis, including small molecules activation, conversion, and degradations. We conclude with a forward-looking perspective discussing the key challenges and opportunity areas for future research.
In a healthy body, ROS (reactive oxygen species) and antioxidants remain in balance. When the balance is disrupted towards an overabundance of ROS, oxidative stress (OS) occurs. OS influences the ...entire reproductive lifespan of a woman and even thereafter (i.e. menopause). OS results from an imbalance between prooxidants (free radical species) and the body's scavenging ability (antioxidants). ROS are a double-edged sword - they serve as key signal molecules in physiological processes but also have a role in pathological processes involving the female reproductive tract. ROS affect multiple physiological processes from oocyte maturation to fertilization, embryo development and pregnancy. It has been suggested that OS modulates the age-related decline in fertility. It plays a role during pregnancy and normal parturition and in initiation of preterm labor. Most ovarian cancers appear in the surface epithelium, and repetitive ovulation has been thought to be a causative factor. Ovulation-induced oxidative base damage and damage to DNA of the ovarian epithelium can be prevented by antioxidants. There is growing literature on the effects of OS in female reproduction with involvement in the pathophysiology of preeclampsia, hydatidiform mole, free radical-induced birth defects and other situations such as abortions. Numerous studies have shown that OS plays a role in the pathophysiology of infertility and assisted fertility. There is some evidence of its role in endometriosis, tubal and peritoneal factor infertility and unexplained infertility. This article reviews the role OS plays in normal cycling ovaries, follicular development and cyclical endometrial changes. It also discusses OS-related female infertility and how it influences the outcomes of assisted reproductive techniques. The review comprehensively explores the literature for evidence of the role of oxidative stress in conditions such as abortions, preeclampsia, hydatidiform mole, fetal embryopathies, preterm labour and preeclampsia and gestational diabetes. The review also addresses the growing literature on the role of nitric oxide species in female reproduction. The involvement of nitric oxide species in regulation of endometrial and ovarian function, etiopathogenesis of endometriosis, and maintenance of uterine quiescence, initiation of labour and ripening of cervix at parturition is discussed. Complex interplay between cytokines and oxidative stress in the etiology of female reproductive disorders is discussed. Oxidant status of the cell modulates angiogenesis, which is critical for follicular growth, corpus luteum formation endometrial differentiation and embryonic growth is also highlighted in the review. Strategies to overcome oxidative stress and enhance fertility, both natural and assisted are delineated. Early interventions being investigated for prevention of preeclampsia are enumerated. Trials investigating combination intervention strategy of vitamin E and vitamin C supplementation in preventing preeclampsia are highlighted. Antioxidants are powerful and there are few trials investigating antioxidant supplementation in female reproduction. However, before clinicians recommend antioxidants, randomized controlled trials with sufficient power are necessary to prove the efficacy of antioxidant supplementation in disorders of female reproduction. Serial measurement of oxidative stress biomarkers in longitudinal studies may help delineate the etiology of some of the diosorders in female reproduction such as preeclampsia.
Mitochondria are essential to cell homeostasis, and alterations in mitochondrial distribution, segregation, and turnover have been linked to complex pathologies such as neurodegenerative diseases and ...cancer. Understanding how these functions are coordinated in specific cell types is a major challenge to discover how mitochondria globally shape cell functionality. In this review, we first describe how mitochondrial transport and dynamics are regulated throughout the cell cycle in yeast and in mammals. Second, we explore the functional consequences of mitochondrial transport and partitioning on cell proliferation, fate acquisition, and stemness and on the way cells adapt their metabolism. Finally, we focus on how mitochondrial clearance programs represent a further layer of complexity for cell differentiation or in the maintenance of stemness. Defining how mitochondrial transport, dynamics, and clearance are mutually orchestrated in specific cell types may help our understanding of how cells can transition from a physiological to a pathological state.
Objective To measure oxidative reduction potential (ORP) in semen and seminal plasma and to establish their reference levels. Design ORP levels were measured in semen and seminal plasma. Setting ...Tertiary hospital. Subject(s) Twenty-six controls and 33 infertile men. Intervention(s) None. Main Outcome Measure(s) Static ORP (sORP) and capacitance ORP (cORP) were measured in semen and seminal plasma at time 0 and 120 minutes. Correlation of ORP was assessed between 1 semen and seminal plasma and 2 time 0 and 120 minutes. The association with sperm parameters was studied in (a) controls and (b) infertile patients, and a receiver operating characteristic curve was generated to establish the sORP cutoff. Result(s) Semen sORP and cORP levels were associated with seminal plasma levels at time 0 and time 120 minutes. In controls and infertile patients, an inverse relationship of sORP levels was established with concentration and total sperm count in semen as well as seminal plasma at time 0 and 120 minutes. Classification of subjects based on sperm motility showed that subjects with abnormal motility present with poor concentration, total count, morphology, and elevated levels of semen and seminal plasma sORP at time 120 minutes. The sORP cutoff of 1.48 in semen and 2.09 in seminal plasma based on motility was able to distinguish subjects with normal semen quality from those with abnormal semen quality. Conclusion(s) The MiOXSYS System can reliably measure ORP levels in semen and seminal plasma. ORP levels are not affected by semen age, making this new technology easy to employ in a clinical setting.
Biomass-derived fatty acids are essential feedstock for producing liquid fuels and value-added chemicals with significantly low CO2 footprints. Herein, Ti3C2Tx and ZnO–Ti3C2Tx catalysts were ...synthesized and demonstrated for the selective hydrodeoxygenation reaction (HDO) of methyl oleate (MO) as a model compound. The synthesized ZnO–Ti3C2Tx catalyst showed 100% conversion of MO with >90% selectivity for the HDO product (n-C18). In addition, the pure Ti3C2Tx demonstrated 100% conversion with a selectivity of 67% for n-C17 hydrocarbon via the decarboxylation route. The highest reduction of CO2 footprint is achieved at 280 °C and 30 bar H2 pressure under solvent-free conditions using ZnO–Ti3C2Tx. The catalyst is recyclable and reusable for five test cycles. The high catalytic selectivity of the ZnO–Ti3C2Tx catalyst towards HDO is attributed to the synergic effect of the Ti and ZnO active sites and the thermally stable structure. This study offers an efficient route for converting edible and non-edible vegetable oils to biofuels by controlling CO2 production.
Two-dimensional (2D) graphene oxide nanosheets serve as an excellent support material for immobilizing metal complexes to deal with the drawbacks of homogeneous catalysis. In this work, we report a ...magnetically retrievable graphene oxide (MGO) based copper nanocatalytic system that has been efficiently exploited for obtaining a series of pharmaceutically and biologically active benzoxazole scaffolds. The nanocatalyst was designed by covalent immobilization of dehydroacetic acid (DHA) onto a magnetic amino-silanized graphene oxide nanosupport which was accompanied by its metallation with copper acetate. The structure of the synthesized MGO hybrid material (Cu@DHA@APTES@MGO) was characterized by numerous physico-chemical techniques such as transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), elemental mapping, atomic absorption spectroscopy (AAS), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) surface area analysis and energy-dispersive X-ray fluorescence spectroscopy (ED-XRF). The fabricated architectures exhibited high efficiency for cyclization of 2-aminophenols and β-diketones with wide substrate scope, excellent functional group tolerance, a higher conversion percentage (>98%) and a high turnover number (TON). The exceptional catalytic activity could be attributed to the 2D architecture of graphene oxide which provides space for trapping of reactants between 2D graphitic overlayers and metal surfaces and the reaction proceeds to afford benzoxazole products with moderate to excellent conversion percentages. Notably, this nanocomposite could be recovered easily through an external magnetic force and reused for multiple runs without any appreciable loss in its catalytic efficacy.
Two-dimensional (2D) graphene oxide nanosheets serve as an excellent support material for immobilizing Cu-DHA complex which demonstrated excellent catalytic efficacy in the synthesis of benzoxazole moieties.
In this letter, we designed a highly selective α‐methylbenzylamine functionalized crown‐ether‐appended calix4arene derived phase transfer catalyst for asymmetric nitroaldol reaction to provide the ...desired nitroaldol adducts in high yields (up to 99 % yield) with good to excellent enantioselectivities (up to 99.8 % ee).
A highly recyclable enantioselctive phase transfer catalyst based of calix4arene‐crown is reported for asymmetric nitroaldol reaction under ambient conditions.
Lignin is amorphous in nature, lacks stereoregularity, and is not susceptible to hydrolytic attack. Despite its resistant nature, it is however degraded by various microorganisms, particularly, ...white-rot fungi. Such fungi are capable of extracellular production of lignin peroxidase, manganese peroxidase, and laccase, the three major enzymes associated with ligninolysis. Though all white-rot fungi do not produce all the three enzymes, laccase occupies an important place in ligninolysis. Laccase belongs to a diverse group of enzymes called oxidoreductases and is also known as benzenediol: oxygen oxidoreductase. They have low substrate specificity. The copper-containing enzyme laccase has been detected in a variety of organisms such as bacteria, fungi, plants, and insects. Mostly, these are extracellular proteins, although intracellular laccases have also been detected in some fungi and insects. Fungal laccases are believed to play a variety of roles, such as, morphogenesis, pathogenesis, and lignin degradation. As an oxidase, laccase is used in many agricultural, industrial, and medicinal applications. Current investigations are focused on laccase-based biooxidation, biotransformation, biosensor, and enzymatic synthesis of organic compounds. By enhancing laccase production using different physiochemical parameters, better understanding of the mechanism for the reactions of interest, and optimizing the catalytic activity of laccase, it can be used in a better way in diverse fields of biotechnology.
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