A. Bhattacharya

Polymer Grafting and Crosslinking

Introduction (Amit Bhattacharya and Paramita Ray). 2. Basic Features and Techniques (Amit Bhattacharya and Paramita Ray). 3. Mechanism and Kinetics (Chris Fellows). 4. Analytical Evidences (Amit Bhattacharya and Paramita Ray). 5. Broader Spectrum: Examples (Inderjeet Kaur and Paramita Ray). 6. In Biomedical Arena (Gauri Misra, Eun Gil, and Tao Lowe). 7. Application in Textiles (Mohammed Rahman). 8. In Automobiles (James Rawlin and Jeremy Swanson). 9. In Cable Technology (Achintya Sen). 10. Separation and purification (Mohamed Nasef). 11. Coatings, Adhesives, and Laminates (James Rawlin and Sharath K. Mendon). 12. In Commodity Plastics (James Rawlin and James Whittermore IV) Future Directions (Amit Bhattacharya).

Optical Resolution of α-Amino Acids by Reverse Osmosis using Enantioselective Polymer Membrane Containing Chiral Metal-Schiff Base Complex

The optical resolution of α-amino acids, arginine and alanine was performed by reverse osmosis at 517.10 kPa and 1034.21 kPa pressures using enantioselective composite nanofiltration membrane prepared by interfacial co-polymerizing, a mixture of Zinc metal Schiffs base complex and piperazine with trimesoyl chloride in-situ on the top of polysulfone ultrafiltration membrane. The chemical composition of the enantioselective layer was determined by ATR-FTIR and X-ray Fluorescence Spectroscopy and surface morphology was studied by scanning electron microscopy. The effect of process parameters such as the operating pressure, permeation time, and concentration of the feed on the performance of membrane was studied. The volumetric flux of aqueous solution of α-amino acids through membrane follows Hegen-Poiseuillie equation. The composite membrane permeates d-enantiomers of α-amino acids preferentially; 54% enantiomeric excess in for d-arginine was achieved. The enantioselective permeability of the membrane is found to be time dependent. The enantioselective property of the membrane has arisen due to a homo-Chiral environment created in the membrane by incorporating chiral ligand Schiff complex in thin film of poly (piperazine trimesamide) polymer on the top of the polysulfone membrane. The composite membrane also exhibits the separation of α-amino acids from their aqueous solutions.

Comparative Study of Enantioseparation of Racemic Tryptophan by Ultrafiltration Using BSA-Immobilized and BSA-Interpenetrating Network Polysulfone Membranes

Effectiveness of Bovine Serum Albumin (BSA) as chiral recognizing protein in enantiomers separation by ultrafiltration technique was studied by immobilizing BSA on the membrane and incorporating BSA as semi-interpenetrating network in the membrane matrix. Separation of racemic tryptophan solution was performed in closed loop cross flow ultrafiltration using BSA immobilized polysulfone membrane and polysulfone membrane having BSA semi-IPN network. The volumetric flux (Jv), the solute flux (Js), the separation factor (α), and the enantiomeric excess (%ee) of two types of membranes at different trans-membrane pressures and permeation times were determined. BSA semi-IPN membrane exhibits higher volumetric as well as solute fluxes compared to BSA immobilized membrane. Separation factor (α) to the order of 1.89 was achieved with BSA immobilized membrane after 8 h of ultrafiltration and in the same duration BSA-IPN membrane exhibited separation factor (α) to the order of 1.62. BSA immobilized membrane exhibits higher enantiomeric excess (30.8%) compared to BSA semi-IPN membrane (23.8%) after 8 hrs. BSA molecules available on membrane as immobilized or as semi-IPN under go complexion with tryptophan enantiomers differently. BSA immobilized membrane performed better separation and enantiomeric purity; however, the solute flux of the membrane decreases.

Drinking water contamination and treatment techniques

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.

Nature of sexual dysfunctions in major depressive disorder and its impact on quality of life.

Background: Adequate sexual expression is an essential part of many human relationships, and may enhance quality of life and provide a sense of physical, psychological, and social well-being. Epidemiological and clinical studies show that depression is associated with impairments of sexual function and satisfaction, even in untreated patients. Most antidepressant drugs have adverse effects on sexual function, but accurate identification of the incidence of treatment-emergent dysfunction has proved troublesome. However, few investigators have reported the base rate for disturbances in sexual desire, arousal, and orgasm or ejaculation in patients with major depressive disorder (MDD) prior to antidepressant treatment. The purpose of this study is to define the frequency of sexual dysfunction (SD) in 60 patients with MDD and examine the relationship between SD and quality of life enjoyment and satisfaction variables. Materials and Methods: A consecutive series of 24 male and 36 female MDD patients diagnosed by SCID-DSM IV assessment completed a series of psychometric measures including a Sexual Function Questionnaire—Arizona Sexual Experience Scale (ASEX) which asked about change in sexual interest and function as well as quality of life of life enjoyment using QLESQ-SF. Results: Over 33.33% of men and 42% of women reported decreased sexual interest. Reduced levels of arousal were more common in both men and women (8-22%) than ejaculatory or orgasm difficulties (11–16%). In women, SDs were more than males. Quality of life was more impaired in sample with SDs than those without dysfunction showing significant impact of SD on quality of life. Limitation and Conclusion: Although limited by a relatively small sample of drug-free patients with MDD, and by the absence of a non-depressed comparison sample, these results emphasize the importance of factors beyond specific drug effects in the assessment of SD in drug naive-depressed patients.

Lipase immobilization on Polysulfone globules and their performances in olive oil hydrolysis

We prepared Polysulfone (PS) globules by pouring the PS solution droplets in to the non-solvent water. PS solutions (10, 15, and 20% (w/v), concentrations) of different viscosities resulted different physical appearances in globules. The lipase immobilizing amount (4.32 mg/g) was maximum for PS 20% globules as it possessed maximum BET pore surface area. The olive oil hydrolytic reaction parameters were fitted into the Lineweaver-Burk plot. The K(m) (apparent) values of all the immobilized globules were higher (83.3mM) with respect to free lipases (62.5mM) where as V(max) (apparent) values followed the reverse trend (129.8 U/mg for 20% and 120.5 U/mg for both 15% and 10% PS immobilized globules and 153.8 U/mg for the free lipase respectively). The hydrolytic activity to olive oil was decreased ( approximately 16-20%) after five cycles.

Studies on Permeation of Bovine Serum Albumin (BSA) Through Photo-Modified Functionalized Asymmetric Membrane

UV-initiated photo-modification by hydrophilic functional moieties (viz. acrylic acid, acrylamide) is performed on the photo-responsive Polyether sulfone (PES) membrane. Characterization of the modified membranes has been done by porometry, Fourier Transform-IR (FTIR), contact angle, thermogravimetry, X-ray diffraction and gel permeation chromatography. The grafting of acrylamide is higher compared to acrylic acid, as is evidenced from weight increase, as well as porometry studies. The separation abilities of Bovine Serum Albumin (BSA) have been experimented through all the membranes and results show that modified membranes possess a better separation ability compared to virgin polyether sulfone. The separation order follows the trend: PES-g-(AM) > PES-g-(AA) > PES. pH dependence conformational changes of BSA macromolecule influence the separation. The increase in pH results in the decreasing trend in separation. The water flux recovery ratio (FRR) for the virgin PES membrane is minimum compared to other two grafted membranes.

Studies on the separation performances of chlorophenol compounds from water by thin film composite membranes

The pressure driven membrane process has been a breakthrough in the removal of pollutants from drinking water. These experiments examined the removal of chlorophenol compounds from water using low pressure membranes. The removal performance of the membranes was based primarily on size exclusion. Apart from size exclusion, the polarity and pKa of the compounds also influences the membrane performance. The molecular size and dipole moments of the respective molecules were calculated using a quantum chemical method. The rejection of pollutants also followed the same trend as salt rejection by the membranes.

Separation of atrazine from water through thin-film composite membranes: influence of salts and surfactants

AbstractThe thin-film composite membrane is aptly named as thin polyamide layer on the asymmetric polysulfone membrane. These membranes have salt rejection abilities, and the order is NaCl > CaCl2. Addition of NaCl increases (17.39% for 500 mg/L for Memb-II), whereas CaCl2 decreases (5.94% for 500 mg/L for Memb-II) atrazine separation. Surfactant-mediated filtrations showed mixed results. Sodium lauryl sulfate (SLS) results better atrazine separation. SLS (200 mg/L) increases 29.72% separation for Memb-II. Contrary to SLS, Cetyl trimethyl ammonium bromide shows little negative influence (10.91%) and for Triton-X-100 (19.3%) it shows more deterioration effect for the same membrane, keeping the same concentration.

Studies on the Effects of Salt and Surfactant in Wet Phase Separation of Polysulfone

This study investigates the effect of additives in the nonsolvent water in terms of cloud point during the phase inversion of Polysulfone (PS) in dimethyl formamide (DMF). The exponential pattern is observed with PS concentration (0.2 to 0.6% (w/w)). It needs a low amount of water to get the cloud point at low temperature. The cloud point varied with the nature of water matrix and depended on the amount of salt, as well as the PS amount. The presence of salts (sodium chloride and sodium sulfate) lowers the cloud point of the solution. The network distribution of the particles at the cloud point is disturbed in the presence of salt. The requirement is more for Sodium lauryl sulfate (SLS) added water to reach the cloud point in the low range of PS solution up to 0.3% PS (w/w). The morphological and distribution pattern of PS particles are very different compared to PS particles produced from pure water. XRD study of PS particles produced from the mixed water system reflects relatively more amorphous character with respect to PS particles from pure water. The presence of both surfactant and salts in water systems also influences the cloud point in synergistic manner.