Studies on the Removal of Malachite Green from Its Aqueous Solution Using Water-Insoluble ß-Cyclodextrin Polymers.

The rising global pollution of natural waters by dyes has brought to light the need for adaptable and efficient removal techniques. To create water-insoluble ß-cyclodextrin (ß-CD) polymers like CA/-CD, TA/-CD, and MA/-CD, several organic acids including citric acid (CA), tartaric acid (TA), and malic acid (MA) were cross-linked with ß-cyclodextrin in this study. The obtained polymers were characterized by different advanced analytical techniques such as FTIR, SEM, and UV-vis spectrophotometry. Malachite green dye was removed from aqueous solutions using the synthesized polymers by adsorption. The adsorption investigation was conducted under several conditions, including pH, adsorbent mass, dye concentration, temperature, contact time, adsorption isotherm, and kinetics. The adsorbent CA/ß-CD shows the highest adsorption of MG dye in all of the conditions because it contains a high number of carboxyl groups. The negatively charged carboxyl ions of CA/ß-CD attract the positively charged MG dye electrostatically and remove MG from aqueous media with an efficiency of 91%. As a result, the findings indicated that water-insoluble polymers based on ß-cyclodextrin are well-suited as inexpensive adsorbents to remove colors from aqueous media.

Ultrafast Intermolecular Interaction Dynamics between NIR-Absorbing Unsymmetrical Squaraines and PCBM: Effects of Halogen Substitution.

Among near-infrared (NIR) dyes, squaraine derivatives are applied as efficient sensitizers in optoelectronic and biomedical devices due to their simple synthesis, intense absorption, and emission and exceptional photochemical stability. The fundamental understanding of the structure-property relationships of sensitizers provides the insight to increase the efficiency of such devices. Here, unsymmetrical squaraine derivatives (ABSQs) with donor-acceptor-donor (D-A-D') architectures having N,N-dimethyl amino anthracene and benzothiazole (ABSQ-H) halogenated with fluoride (ABSQ-F), chloride (ABSQ-Cl), and bromide (ABSQ-Br) were synthesized to understand the effect of halogen on the photophysical properties and intermolecular interaction dynamics with phenyl-C61-butyric acid methyl ester (PCBM), which is used widely as an electron acceptor in bulk heterojunction-based devices. Interestingly, ABSQ-H exhibited intense absorption (ε ∼ 6.72 × 104 M-1 cm-1) spectra centered at ∼660 nm. Upon halogen substitution, a bathochromic shift in the absorption spectra with an increase of molar absorptivity was observed (ε ∼ 8.59 × 104 M-1 cm-1), which is beneficial for NIR light harvesting. The femtosecond transient absorption spectra of ABSQs revealed that the polarity of the solvent controlled the excited-state relaxation dynamics. Upon addition of PCBM, the fluorescence intensity and dynamics of halogenated ABSQs were quenched, and the formation of a squaraine radical cation was observed, reflecting the occurrence of intermolecular charge-transfer dynamics between ABSQs and PCBM. Thus, the observation of a bathochromic shift with intense absorption and an efficient intermolecular interaction with PCBM upon halogenation of ABSQs provide a design strategy for the development of unsymmetrical squaraine derivatives for bulk heterojunction-based optoelectronic devices.

Direct evidence of solvent polarity governing the intramolecular charge and energy transfer: ultrafast relaxation dynamics of push-pull fluorene derivatives.

Photoinduced charge and energy transfer are significant photophysical processes controlling the efficiency of photosynthesis and molecular electronics. Here, the influence of solvent polarity and excitation wavelength on the dynamics of excited state relaxation pathways of a push-pull chromophore (PXFCN), where phenoxazine and cyano fluorene acted as a donor and an acceptor, respectively, is investigated in detail by using steady state spectroscopy, nanosecond and femtosecond transient absorption spectroscopy and picosecond emission spectroscopy. In acetonitrile (ACN), the steady state emission spectra of PXFCN exhibited three maxima at around 330, 405 and 620 nm covering the complete continuum range (CIE coordinates of 0.32, 0.40) with an absolute quantum yield of ≈0.12. The aggregation induced emission with an increased quantum yield of ≈0.32 was observed in a tetrahydrofuran and water mixture due to the formation of nano-aggregates. Interestingly the steady state and time resolved emission spectra of PXFCN in ACN obtained upon excitation at different wavelengths revealed the presence of both intramolecular charge and energy transfer processes, whereas in cyclohexane (CHX) the emission originated mainly from the local excited state revealing efficient intramolecular energy transfer. The femtosecond transient absorption spectrum in the polar solvent, ACN, shows that the excited state relaxation pathway is controlled by solvent stabilized twisted intramolecular charge transfer dynamics limiting the formation of the triplet state. However in the case of CHX, the charge transfer state formed upon photoexcitation decayed to the triplet state by geminate charge recombination. The nanosecond transient absorption spectra manifest the dominant feature of the triplet state and the charge transfer state in CHX and ACN, respectively, and their complete dynamics were obtained. Thus based on the transient absorption and emission spectra, it is inferred that the intramolecular charge transfer occurring along with the energy transfer is controlled by the polarity of the solvent through conformational changes leading to a favourable position yielding the charge and energy transfer between the donor and acceptor moieties.

Integrating modern dermatology and Ayurveda in the treatment of vitiligo and lymphedema in India.

BACKGROUND: Globally, governments have recognized the growing popularity of Complementary and Alternative Medicines and the possibility of their combined use with biomedicine. Decisions within the Government of India have led to a conducive environment for conducting clinical studies, to achieve integration of more than one system of medicine, so that their combined benefits can be brought to bear on chronic, difficult-to-treat conditions. AIM: To develop integrative dermatology treatment protocols for patients with long-standing skin diseases who have received treatment from many centers. MATERIALS AND METHODS: A team of doctors from modern dermatology, Ayurveda, yoga therapy, and homeopathy studied recruited patients to develop mutual orientation on each therapeutic system and a working knowledge of approach to their clinical diagnosis. Six-hundred thirty-eight patients affected by lower limb lymphedema requiring skin care as a major part of treatment were treated integrating modern dermatology and Ayurveda. Three-hundred eighty-one vitiligo patients were examined and treated to understand the clinical presentations and treatment options in Ayurveda. RESULTS: A two-step cluster analysis performed by SPSS Version 16 showed average volume reductions of 13.3% and 23% on day 14, 19.7% and 31.1% on day 45, and 23.4% and 39.7% on day 90 of treatment in small and large lymphedematous limbs. Inflammatory episodes before the onset on this treatment was reported by 79.5% of our lymphedema patients, and 9.4% reported this at the end of three months after our treatment. Among vitiligo patients, we found that 39.6% of patients had kapha, 39.8% pitta, 10.8% had vatha and 0.52% has tridoshaja presentation. There are over 100 treatment options available in Ayurveda to treat vitiligo. DISCUSSION: Each system of medicine recognizes the same disease albeit with minor difference in description. Skin care procedures like washing and emollients restore the barrier function and skin health. We have converged Ayurvedic skin care with that of dermatology with an aim of achieving patient management that is better than that achievable by a single system alone. Overload of the lymphatic system due to loss of epidermal barrier function and consequent inflammation from bacteria and soil irritants is responsive to selected Ayurvedic herbal preparations. CONCLUSION: It is evident that integration at the therapeutic level is possible, although the pathological basis is interpreted differently. Irrespective of background understanding of the given disease, a mutually oriented multisystem therapeutic team was able to effectively use medicines from more than one system of medicine and to develop guidelines for their prescription and a patient care algorithm.

Micro-treatment options for components of organic fraction of MSW in residential areas.

There is a growing interest in management of MSW through micro-treatment of organic fraction of municipal solid wastes (OFMSW) in many cities of India. The OFMSW fraction is high (>80%) in many pockets within South Indian cities like Bangalore, Chikkamagalur, etc. and is largely represented by vegetable, fruit, packing and garden wastes. Among these, the last three have shown problems for easy decomposition. Fruit wastes are characterized by a large pectin supported fraction that decomposes quickly to organic acids (becomes pulpy) that eventually slow down anaerobic and aerobic decomposition processes. Paper fraction (newsprint and photocopying paper) as well as paddy straw (packing), bagasse (from cane juice stalls) and tree leaf litter (typical garden waste and street sweepings) are found in reasonably large proportions in MSW. These decompose slowly due to poor nutrients or physical state. We have examined the suitability of these substrates for micro-composting in plastic bins by tracking decomposition pattern and physical changes. It was found that fruit wastes decompose rapidly to produce organic acids and large leachate fraction such that it may need to be mixed with leachate absorbing materials (dry wastes) for good composting. Leaf litter, paddy straw and bagasse decompose to the tune of 90, 68 and 60% VS and are suitable for composting micro-treatment. Paper fractions even when augmented with 10% leaf compost failed to show appreciable decomposition in 50 days. All these feedstocks were found to have good biological methane potential (BMP) and showed promise for conversion to biogas under a mixed feed operation. Suitability of this approach was verified by operating a plug-flow type anaerobic digester where only leaf litter gathered nearby (as street sweepings) was used as feedstock. Here only a third of the BMP was realized at this scale (0.18 m(3 )biogas/kg VS 0.55 m(3)/kg in BMP). We conclude that anaerobic digestion in plug-flow like digesters appear a more suitable micro-treatment option (2-10 kg VS/day) because in addition to compost it also produces biogas for domestic use nearby.

Protein kinase C regulates transcription of the human guanylate cyclase C gene.

Guanylate cyclase C is the receptor for the bacterial heat-stable enterotoxins and guanylin family of peptides, and mediates its action by elevating intracellular cGMP levels. Potentiation of ligand-stimulated activity of guanylate cyclase C in human colonic T84 cells is observed following activation of protein kinase C as a result of direct phosphorylation of guanylate cyclase C. Here, we show that prolonged exposure of cells to phorbol esters results in a decrease in guanylate cyclase C content in 4beta-phorbol 12-myristate 13-acetate-treated cells, as a consequence of a decrease in guanylate cyclase C mRNA levels. The reduction in guanylate cyclase C mRNA was inhibited when cells were treated with 4beta-phorbol 12-myristate 13-acetate (PMA) in the presence of staurosporine, indicating that a primary phosphorylation event by protein kinase C triggered the reduction in RNA levels. The reduction in guanylate cyclase C mRNA levels was not due to alterations in the half-life of guanylate cyclase C mRNA, but regulation occurred at the level of transcription of guanylate cyclase C mRNA. Expression in T84 cells of a guanylate cyclase C promoter-luciferase reporter plasmid, containing 1973 bp of promoter sequence of the guanylate cyclase C gene, indicated that luciferase activity was reduced markedly on PMA treatment of cells, and the protein kinase C-responsive element was present in a 129-bp region of the promoter, containing a HNF4 binding element. Electrophoretic mobility shift assays using an oligonucleotide corresponding to the HNF4 binding site, indicated a decrease in binding of the factor to its cognate sequence in nuclear extracts prepared from PMA-treated cells. We therefore show for the first time that regulation of guanylate cyclase C activity can be controlled at the transcriptional level by cross-talk with signaling pathways that modulate protein kinase C activity. We also suggest a novel regulation of the HNF4 transcription factor by protein kinase C.

Mu 1A deficiency induces a profound increase in MPR300/IGF-II receptor internalization rate.

The mannose-6-phosphate/IGF-II receptor MPR300 mediates sorting of lysosomal enzymes from the trans-Golgi network to endosomes and endocytosis of hormones, for example, of IGF-II. We analyzed transport of MPR300 in mu1A-adaptin-deficient fibroblasts, which lack a functional AP-1 clathrin adaptor complex. In mu1A-adaptin-deficient fibroblasts, the homologous MPR46 accumulates in endosomes due to a block in retrograde transport to the trans-Golgi network. The MPR300-mediated endocytosis is markedly enhanced. We demonstrate that the seven-fold increase in endocytosis is not associated with an increased steady-state concentration of receptors at the plasma membrane, but with an increased internalization rate of MPR300. Internalization of other receptors that are also endocytosed by AP-2 is not affected. More MPR300 receptors are found in clathrin-coated pits of the plasma membrane, whereas outside coated-areas, more MPR300 are concentrated in clusters and all intracellular receptors reside in endosomes, which are in equilibrium with the plasma membrane. Thus AP-1-mediated transport of MPR300 from endosomes to the TGN controls indirectly the recycling rate of the receptor between the plasma membrane and endosomes.

Biochemical characterization of the intracellular domain of the human guanylyl cyclase C receptor provides evidence for a catalytically active homotrimer.

Guanylyl cyclase C (GCC) is the receptor for the family of guanylin peptides and bacterial heat-stable enterotoxins (ST). The receptor is composed of an extracellular, ligand-binding domain and an intracellular domain with a region of homology to protein kinases and a guanylyl cyclase catalytic domain. We have expressed the entire intracellular domain of GCC in insect cells and purified the recombinant protein, GCC-IDbac, to study its catalytic activity and regulation. Kinetic properties of the purified protein were similar to that of full-length GCC, and high activity was observed when MnGTP was used as the substrate. Nonionic detergents, which stimulate the guanylyl cyclase activity of membrane-associated GCC, did not appreciably increase the activity of GCC-IDbac, indicating that activation of the receptor by Lubrol involved conformational changes that required the transmembrane and/or the extracellular domain. The guanylyl cyclase activity of GCC-IDbac was inhibited by Zn(2+), at concentrations shown to inhibit adenylyl cyclase, suggesting a structural homology between the two enzymes. Covalent cross-linking of GCC-IDbac indicated that the protein could associate as a dimer, but a large fraction was present as a trimer. Gel filtration analysis also showed that the major fraction of the protein eluted at a molecular size of a trimer, suggesting that the dimer detected by cross-linking represented subtle differences in the juxtaposition of the individual polypeptide chains. We therefore provide evidence that the trimeric state of GCC is catalytically active, and sequences required to generate the trimer are present in the intracellular domain of GCC.