Central Salt and Marine Chemicals Research Institute

Water is of fundamental importance for life on earth. The synthesis and structure of cell constituents and transport of nutrients into the cells as well as body metabolism depend on water. The contaminations present in water disturb the spontaneity of the mechanism and result in long/short-term diseases. The probable contaminations and their possible routes are discussed in the present review. Continued research efforts result in some processes/technologies to remove the contaminations from water. The review includes concepts and potentialities of the technologies in a comprehensible form. It also includes some meaningful hybrid technologies and promising awaited technologies in coming years.

The low water solubility of pharmacoactive molecules limits their pharmacological potential, but the solubility parameter cannot compromise, and so different approaches are employed to enhance their bioavailability. Pharmaceutically active molecules with low solubility convey a higher risk of failure for drug innovation and development. Pharmacokinetics, pharmacodynamics, and several other parameters, such as drug distribution, protein binding and absorption, are majorly affected by their solubility. Among all pharmaceutical dosage forms, oral dosage forms cover more than 50%, and the drug molecule should be water-soluble. For good therapeutic activity by the drug molecule on the target site, solubility and bioavailability are crucial factors. The pharmaceutical industry's screening programs identified that around 40% of new chemical entities (NCEs) face various difficulties at the formulation and development stages. These pharmaceuticals demonstrate less solubility and bioavailability. Enhancement of the bioavailability and solubility of drugs is a significant challenge in the area of pharmaceutical formulations. According to the Classification of Biopharmaceutics, Class II and IV drugs (APIs) exhibit poor solubility, lower bioavailability, and less dissolution. Various technologies are discussed in this article to improve the solubility of poorly water-soluble drugs, for example, the complexation of active molecules, the utilization of emulsion formation, micelles, microemulsions, cosolvents, polymeric micelle preparation, particle size reduction technologies, pharmaceutical salts, prodrugs, the solid-state alternation technique, soft gel technology, drug nanocrystals, solid dispersion methods, crystal engineering techniques and nanomorph technology. This review mainly describes several other advanced methodologies for solubility and bioavailability enhancement, such as crystal engineering, micronization, solid dispersions, nano sizing, the use of cyclodextrins, solid lipid nanoparticles, colloidal drug delivery systems and drug conjugates, referring to a number of appropriate research reports.

Microbial polysaccharides are multifunctional and can be divided into intracellular polysaccharides, structural polysaccharides and extracellular polysaccharides or exopolysaccharides (EPS). Extracellular polymeric substances (EPS), produced by both prokaryotes (eubacteria and archaebacteria) and eukaryotes (phytoplankton, fungi, and algae), have been of topical research interest. Newer approaches are carried out today to replace the traditionally used plant gums by their bacterial counterparts. The bacterial exopolysaccharides represent a wide range of chemical structures, but have not yet acquired appreciable significance. Chemically, EPS are rich in high molecular weight polysaccharides (10 to 30 kDa) and have heteropolymeric composition. They have new-fangled applications due to the unique properties they possess. Owing to this, exopolysaccharides have found multifarious applications in the food, pharmaceutical and other industries. Hence, the present article converges on bacterial exopolysaccharides.

The synthesis and characterization of a novel nanocomposite is reported that was developed as an efficient adsorbent for the removal of toxic methylene blue (MB) and methyl violet (MV) from aqueous solution. The nanocomposite comprises hydrolyzed polyacrylamide grafted onto xanthan gum as well as incorporated nanosilica. The synthesis exploits the saponification of the grafted polyacrylamide and the in situ formation of nanoscale SiO2 by a sol-gel reaction, in which the biopolymer matrix promotes the silica polymerization and therefore acts as a novel template for nanosilica formation. The detailed investigation of the kinetics and the adsorption isotherms of MB and MV from aqueous solution showed that the dyes adsorb rapidly, in accordance with a pseudo-second-order kinetics and a Langmuir adsorption isotherm. The entropy driven process was furthermore found to strongly depend on the point of zero charge (pzc) of the adsorbent. The remarkably high adsorption capacity of dyes on the nanocomposites (efficiency of MB removal, 99.4%; maximum specific removal Qmax, 497.5 mg g(-1); and efficiency of MV removal, 99.1%; Qmax, 378.8 mg g(-1)) is rationalized on the basis of H-bonding interactions as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules. Because of the excellent regeneration capacity the nanocomposites are considered interesting materials for the uptake of, for instance, toxic dyes from wastewater.

Two Arabidopsis thaliana extragenic mutations that suppress NaCl hypersensitivity of the sos3-1 mutant were identified in a screen of a T-DNA insertion population in the genetic background of Col-0 gl1 sos3-1. Analysis of the genome sequence in the region flanking the T-DNA left border indicated that sos3-1 hkt1-1 and sos3-1 hkt1-2 plants have allelic mutations in AtHKT1. AtHKT1 mRNA is more abundant in roots than shoots of wild-type plants but is not detected in plants of either mutant, indicating that this gene is inactivated by the mutations. hkt1-1 and hkt1-2 mutations can suppress to an equivalent extent the Na(+) sensitivity of sos3-1 seedlings and reduce the intracellular accumulation of this cytotoxic ion. Moreover, sos3-1 hkt1-1 and sos3-1 hkt1-2 seedlings are able to maintain [K(+)](int) in medium supplemented with NaCl and exhibit a substantially higher intracellular ratio of K(+)/Na(+) than the sos3-1 mutant. Furthermore, the hkt1 mutations abrogate the growth inhibition of the sos3-1 mutant that is caused by K(+) deficiency on culture medium with low Ca(2+) (0.15 mM) and <200 microM K(+). Interestingly, the capacity of hkt1 mutations to suppress the Na(+) hypersensitivity of the sos3-1 mutant is reduced substantially when seedlings are grown in medium with low Ca(2+) (0.15 mM). These results indicate that AtHKT1 is a salt tolerance determinant that controls Na(+) entry and high affinity K(+) uptake. The hkt1 mutations have revealed the existence of another Na(+) influx system(s) whose activity is reduced by high [Ca(2+)](ext).

Abstract Thin‐film composite membranes comprising a polyamide nanofilm separating layer on a support material are state of the art for desalination by reverse osmosis. Nanofilm thickness is thought to determine the rate of water transport through the membranes; although due to the fast and relatively uncontrolled interfacial polymerization reaction employed to form these nanofilms, they are typically crumpled and the separating layer is reported to be ≈50–200 nm thick. This crumpled structure has confounded exploration of the independent effects of thickness, permeation mechanism, and the support material. Herein, smooth sub‐8 nm polyamide nanofilms are fabricated at a free aqueous–organic interface, exhibiting chemical homogeneity at both aqueous and organic facing surfaces. Transfer of these ultrathin nanofilms onto porous supports provides fast water transport through the resulting nanofilm composite membranes. Manipulating the intrinsic nanofilm thickness from ≈15 down to 8 nm reveals that water permeance increases proportionally with the thickness decrease, after which it increases nonlinearly to 2.7 L m −2 h −1 bar −1 as the thickness is further reduced to ≈6 nm.

[structure: see text] Novel colorimetric receptors for selective fluoride ion sensing containing anthraquinone as chromogenic signaling subunit and urea (N,N' '-(9,10-dihydro-9,10-dioxo-1,2-anthracenediyl)bis[N'-phenyl])/thiourea (N,N' '-(9,10-dihydro-9,10-dihydro-9,10-dioxo-1,2-antrhacenediyl)bis[N-phenyl]) binding sites have been reported. These receptors have shown no affinity for other halide ions (Cl-, Br-, and I- ions). Well-defined color change in the visible region of the spectrum was observed upon addition of fluoride ion in DMSO/CH3CN solution of the receptors 1 and 2.

Self aggregation of the ionic liquids, 1-butyl-3-methylimidazolium chloride [C4mim][Cl], 3-methyl-1-octylimidazolium chloride [C8mim][Cl], 1-butyl-3-methylimidazolium tetrafluoroborate [C4mim][BF4], N-butyl-3-methylpyridinium chloride [C4mpy][Cl], in aqueous solution has been investigated through 1H nuclear magnetic resonance (NMR) and steady-state fluorescence spectroscopy. Aggregation properties were determined by application of mass action theory to the concentration dependence of 1H NMR chemical shifts. Aggregation properties showed fairly good agreement with the previously reported results obtained from small angle neutron scattering, conductivity, and surface tension measurements. A detailed analysis of chemical shifts of water and various protons in ILs has been employed to probe the aggregate structure. Fluorescence spectroscopy provided important information about the critical aggregation concentration (cac) and the microenvironment of the aggregates. We could also observe a break point quite consistent with that of 1H NMR and fluorescence spectroscopy at cac from the concentration dependence of refractive index measurements. Standard free energies of aggregation DeltaGom of various ILs derived using the refractive index/concentration profiles were found comparable to those of classical ionic surfactants.

A field experiment was conducted during the rainy (kharif) season in Indian in 2006 to study the effects of foliar applications of different concentrations of seaweed extract (prepared from Kappaphycus alvarezii) on nutrient uptake, growth and yield of soybean [Glycine max (L.) Merr.] grown under rainfed conditions without the application of chemical fertilizers. The foliar spray was applied twice at seven concentrations (0; 2.5; 5; 7.5; 10; 12.5 and 15% v/v) of seaweed extract. Foliar applications of seaweed extract significantly enhanced yield parameters. The highest grain yield was recorded with applications of 15% seaweed extract, followed by 12.5% seaweed extract that resulted in 57% and 46% increases respectively compared to the control. The maximum straw yield was also achieved with 15% seaweed extract application. Improved nutrient uptake (N, P, K and S) was also observed with seaweed extract applications. Thus, under rainfed soybean production, foliar applications of seaweed extracts could be a promising option for yield enhancement.

Abstract Membranes with ultrahigh ion selectivity and high liquid permeance are needed to produce high‐quality product water with increased recovery and process efficiency in water desalination. The narrow pore size distribution and controlled surface charge in the separation layer of nanofiltration membranes significantly improve the ion selectivity through molecular sieving and Donnan exclusion of co‐ions. Here, the ultraselective and yet highly water permeable polyamide nanofilm composite nanofiltration membranes developed by precisely controlling the kinetics of the interfacial polymerization reaction by maintaining the stoichiometric equilibrium at the interface is reported. The kinetically favorable stoichiometric equilibrium condition prohibits the formation of aggregate pores in the nanofilm and leads to the formation of narrow network pores with a high surface negative charge. Nanofilms are designed with a controlled degree of crosslinking and made as thin as ≈7 nm to achieve increased water permeance. The ultraselective membranes exhibit up to 99.99% rejection of divalent salt (Na 2 SO 4 ) and demonstrate monovalent to divalent ion selectivity of &gt;4000. The selectivity of these nanofilm composite membranes is beyond the permeance–selectivity upper‐bound line of the state‐of‐the‐art nanofiltration membranes and one to two orders of magnitude higher than the commercially available membranes with pure water permeances of up to 23 L m −2 h −1 bar −1 . The fabrication process is scalable for membrane manufacturing.

Nucleophilic heterocyclic carbene-catalyzed cyclopentannulation of enals and chalcones via homoenolate has been observed for the first time. Serendipitously, the reaction lead to a very efficient synthesis of 3,4-trans-disubstituted-1-aryl cyclopentenes instead of the expected cyclopentanones. The strategy works well with thienylidene tetralone also, leading to the tricyclic cyclopentene derivative.

Isostructural Zn(II)/Cd(II) mixed ligand coordination polymers (CPs) {[M(IPA)(L)]}n (CP1 and CP2) built from isophthalic acid (H2IPA) and 3-pyridylcarboxaldehyde nicotinoylhydrazone (L) were prepared using versatile synthetic routes: viz., diffusion of precursor solutions, conventional reflux methods, and green mechanochemical (grinding) reactions. Both robust CPs synthesized by different routes were characterized by various analytical methods, and their thermal and chemical stability as well as the phase purity was established. Crystallographic studies revealed that CP1 and CP2 are isostructural frameworks and feature a double-lined two-dimensional network composed of Zn2+/Cd2+ nodes connected through IPA and pillared by the Schiff base ligand L with a double-walled edge. The photoluminescent (PL) properties of CP1 and CP2 have been exploited as dual detection fluorosensors for hexavalent chromate anions (CrO42–/Cr2O72–) and 2,4,6-trinitrophenol (TNP) because it was observed that the emission intensity of aqueous suspensions of CPs selectively quenches by chromate anions or TNP among large pools of different anions or nitro compounds, respectively. Competitive experiments in the presence of interfering anions/other nitro compounds also revealed no major effect in the quenching efficiency, suggesting the selective detection of hexavalent chromate anions as well as TNP by the LCPs. The limits of detection by CP1 for CrO42–/Cr2O72– and TNP are 4 ppm/4 ppm and 28 ppb, respectively, whereas the limits of detection by CP2 for the same analytes are 1 ppm/1 ppm and 14 ppb, respectively. A probable mechanism for the quenching phenomena is also discussed.

Seaweed-associated bacteria play a crucial role in morphogenesis and growth of seaweeds (macroalgae) in direct and/or indirect ways. Bacterial communities belonging to the phyla Proteobacteria and Firmicutes are generally the most abundant on seaweed surfaces. Associated bacterial communities produce plant growth-promoting substances, quorum sensing signalling molecules, bioactive compounds and other effective molecules that are responsible for normal morphology, development and growth of seaweeds. Also, bioactive molecules of associated bacteria determine the presence of other bacterial strains on seaweeds and protect the host from harmful entities present in the pelagic realm. The ecological functions of cross-domain signalling between seaweeds and bacteria have been reported as liberation of carpospores in the red seaweeds and settlement of zoospores in the green seaweeds. In the present review, the role of extracellular polymeric substances in growth and settlement of seaweeds spores is also highlighted. To elucidate the functional roles of associated bacteria and the molecular mechanisms underlying reported ecological phenomena in seaweeds requires a combined ecological, microbiological and biochemical approach.

All cellular processes are the results of synchronized actions of several intracellular biochemical pathways. Recent emphasis is to visualize such pathways using appropriate small molecular reagents, dye-labeled proteins, and genetically encoded fluorescent biosensors that produce a luminescence ON response either on selective binding or on reacting with an analyte that is produced through a specific biochemical/enzymatic transformation. Studying such enzymatic processes by probing the fluorescence response as the read-out signal is expected to provide important insights into crucial biochemical transformations induced by an enzyme in its native form. Many of such studies are extended for monitoring enzymatic transformations under in vitro or in vivo condition. A few of the recent reports reveal that such molecular probes are even capable of quantifying abnormal levels of enzymes in real-time and is linked to the key area of clinical diagnostics and chemical biology. A synchronized analysis of all such reports helps in developing a rationale for designing purpose-built molecular probes or chemodosimeters as well as newer reagents for studying crucial enzymatic process or quantification of the respective enzyme. In this review, an attempt will be there to highlight several recent bioimaging reagents and studies that have provided insights into crucial biochemical or enzymatic transformations.

In recent years, marine organisms including seaweeds have been highlighted as potential sources of useful metabolites and bioactive compounds, with vast biological and physiological activities. Seaweeds have long been used as a food source, for medicinal purposes, and as dietary supplements in various Asian countries, and their potential benefits have recently attracted the attention of many Western and European countries. Their commercial value depends on their applications in the food, nutraceutical, and pharmaceutical industries. Seaweeds are considered a potential source of nutraceuticals or functional foods, and analysis of taste-oriented motives has revealed that seaweeds are preferentially selected over other types of marine foods by seafood consumers and people with high levels of health, education, and living status. It is a general perception that health conscious people prefer environmentally friendly food sources, and present an opportunity to focus on seaweed-based foods, which have significant nutritional benefits to humans. Among the various bioactive constituents, seaweed polysaccharides have been proven to possess various beneficial properties including anticoagulant, anti-inflammatory, antioxidant, anticarcinogenic, and antiviral activities. The diversity and composition of seaweed polysaccharides play vital roles in these biological activities. Seaweeds are a rich source of sulfated polysaccharides, which are responsible for much of the bioactivity, as they can interact with various textures and cellular proteins. A number of toxicological assays and clinical trials suggest that the ingestion of seaweeds as functional foods should be considered worldwide to improve immune responses. In this review, different polysaccharides from seaweeds and their compositions and potential nutraceutical applications are discussed.

Newly synthesized rhodamine derivatives, L(1) and L(2), are found to bind specifically to Hg(2+) or Cr(3+) in presence of large excess of other competing ions with associated changes in their optical and fluorescence spectral behavior. These spectral changes are significant enough in the visible region of the spectrum and thus, allow the visual detection. For L(1), the detection limit is even lower than the permissible [Cr(3+)] or [Hg(2+)] in drinking water as per standard U.S. EPA norms; while the receptor, L2 could be used as a ratiometric sensor for detection of Cr(3+) and Hg(2+) based on the resonance energy transfer (RET) process involving the donor naphthalimide and the acceptor Cr(3+)/Hg(2+)-bound xanthene fragment. Studies reveal that these two reagents could be used for recognition and sensing of Hg(2+)/Cr(3+). Further, confocal laser microscopic studies confirmed that the reagent L(2) could also be used as an imaging probe for detection of uptake of these ions in A431 cells.

Halophytes have demonstrated their capability to thrive under extremely saline conditions and thus considered as one of the best germplasm for saline agriculture. Salinity is a worldwide problem, and the salt-affected areas are increasing day-by-day because of scanty rainfall, poor irrigation system, salt ingression, water contamination and other environmental factors. The salinity stress tolerance mechanism is a very complex phenomenon, and some pathways are coordinately linked for imparting salinity tolerance. Though a number of salt responsive genes have been reported from the halophytes, there is always a quest for promising stress-responsive genes that can modulate plant physiology according to the salt stress. Halophytes such as Aeluropus, Mesembryanthemum, Suaeda, Atriplex, Thellungiella, Cakile and Salicornia serve as a potential candidate for the salt-responsive genes and promoters. Several known genes like antiporters (NHX, SOS, HKT, VTPase), ion channels (Cl-, Ca2+, aquaporins), antioxidant encoding genes (APX, CAT, GST, BADH, SOD) and some novel genes such as USP, SDR1, SRP etc. were isolated from halophytes and explored for developing stress tolerance in the crop plants (glycophytes). It is evidenced that stress triggers salt sensors that lead to the activation of stress tolerance mechanisms which involve multiple signaling proteins, up- or down- regulation of several genes, and finally the distinctive or collective effects of stress-responsive genes. In this review, halophytes are discussed as an excellent platform for salt responsive genes which can be utilized for developing salinity tolerance in crop plants through genetic engineering.

Halophytes are plants which naturally survive in saline environment. They account for ∼1% of the total flora of the world. They include both dicots and monocots and are distributed mainly in arid, semi-arid inlands and saline wet lands along the tropical and sub-tropical coasts. Salinity tolerance in halophytes depends on a set of ecological and physiological characteristics that allow them to grow and flourish in high saline conditions. The ability of halophytes to tolerate high salt is determined by the effective coordination between various physiological processes, metabolic pathways and protein or gene networks responsible for delivering salinity tolerance. The salinity responsive proteins belong to diverse functional classes such as photosynthesis, redox homeostasis; stress/defense, carbohydrate and energy metabolism, protein metabolism, signal transduction and membrane transport. The important metabolites which are involved in salt tolerance of halophytes are proline and proline analog (4-hydroxy-N-methyl proline), glycine betaine, pinitol, myo-inositol, mannitol, sorbitol, O-methylmucoinositol, and polyamines. In halophytes, the synthesis of specific proteins and osmotically active metabolites control ion and water flux and support scavenging of oxygen radicals under salt stress condition. The present review summarizes the salt tolerance mechanisms of halophytes by elucidating the recent studies that have focused on proteomic, metabolomic, and ionomic aspects of various halophytes in response to salinity. By integrating the information from halophytes and its comparison with glycophytes could give an overview of salt tolerance mechanisms in halophytes, thus laying down the pavement for development of salt tolerant crop plants through genetic modification and effective breeding strategies.

This study was focused on the application of ultraviolet light emitting diodes (UV-LED) as an alternate source for the photocatalytic degradation of methylene blue (MB), which was used as a model compound. A simple reactor arrangement was made to carry out the photocatalytic degradation of methylene blue dye. The photocatalytic activity of P-25 Degussa TiO2 was evaluated using UV-LED reactor. The decomposition of MB dye in aqueous solution by TiO2 photocatalytic process with the UV-LED was found to be technically feasible. The effects of various parameters such as catalyst loading, initial dye concentration, pH, and addition of H2O2 on decolorization and degradation have been investigated to find the optimum conditions. The complete mineralization of MB dye (3.12 × 10−5 M) was confirmed by chemical oxygen demand analysis. Results demonstrated that the UV-LED/TiO2 process can effectively degrade methylene blue dye with optimum conditions.

Nanocrystalline TiO2 was synthesized by controlled hydrolysis of titanium tetraisopropoxide. The anatase phase was converted to rutile phase by thermal treatment at 1023 K for 11 h. The catalysts were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), Fourier-transform infrared absorption spectrophotometry (FT-IR) and N2 adsorption (BET) at 77 K. This study compare the photocatalytic activity of the anatase and rutile phases of nanocrystalline TiO2 for the degradation of acetophenone, nitrobenzene, methylene blue and malachite green present in aqueous solutions. The initial rate of degradation was calculated to compare the photocatalytic activity of anatase and rutile nanocrystalline TiO2 for the degradation of different substances under ultraviolet light irradiation. The higher photocatalytic activity was obtained in anatase phase TiO2 for the degradation of all substances as compared with rutile phase. It is concluded that the higher photocatalytic activity in anatase TiO2 is due to parameters like band-gap, number of hydroxyl groups, surface area and porosity of the catalyst.