Md Tanim-Al Hassan | New Jersey Institute of Technology (original) (raw)

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Papers by Md Tanim-Al Hassan

This study presents the kinetic and thermodynamic investigations of the adsorption of crystal vio... more This study presents the kinetic and thermodynamic investigations of the adsorption of crystal violet (CV) on used black tea leaves (UBTL) from aqueous solution to evaluate the feasibility of the process. The effects of concentration, solution pH and temperature on adsorption kinetics were carried out in batch process. Kinetic studies have shown that the adsorption data partially follow simple first order, second order and pseudo second order kinetic equations for different initial concentrations at pH 2.0. The equilibrium amount adsorbed, equilibrium concentration and rate constant were calculated from better fitted pseudo second order kinetic plots for different initial concentrations. The equilibrium amount adsorbed (200 mg/g at 30 o C) increased with the increase of temperature, indicated endothermic nature of the adsorption. The apparent activation energy of adsorption was determined from Arrhenius plot using pseudo second order rate constant and the value, E a = 83.1 kJ/mol, revealed the process is chemisorption. Thermodynamic parameters: H o , G o and S o , were determined from the equilibrium adsorption constant and the results obtained confirmed that the adsorption process was feasible, less spontaneous and endothermic. The equilibrium amount adsorbed was found to be increased with increase of solution pH from 2.0 to 6.0 indicating electrostatic interaction between cationic CV with anionic surface of UBTL dominated at higher pH due to the low zero point charge pH of UBTL.

The present study investigates the potential use of used black tea leaves (UBTL) for the removal ... more The present study investigates the potential use of used black tea leaves (UBTL) for the removal of Crystal Violet (CV) from acidic solution in batch process. The influences of different adsorption parameters such as contact time, concentration, processing temperatures and ionic strength were investigated. UV-visible spectrophotometer was used to analysis CV at a specific pH (6.0) of solution. Several model isotherms were depicted at different processing temperatures using acidic solution of pH 2.0. Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich (D-R) and Florry-Huggins model equation were subjected to analyze the equilibrium adsorption data. The experimental data reveals Langmuir and D-R models comparatively better fitted than Freundlich, Tempkin and Florry-Huggins models. The equilibrium adsorption capacity (qm) computed from Langmuir equation is 184.1 mg/g at 30 o C which is increased with increase of processing temperature. The adsorption energy (E) calculated from D-R model indicates physical adsorption which plays cardinal role in this adsorption process. The value of separation factor informs that the adsorption process is favorable in nature. The effect of electrolytes (NaCl and NaNO3) suggests a possible adsorption mechanism of CV onto UBTL. The values of thermodynamic variables such as Gibbs free energy (∆Gads), enthalpy (∆Hads) and entropy (∆Sads) suggests the adsorption process is non-spontaneous, physisorption with negligible amount of fragmentation of dye molecules.

Please note that technical editing may introduce minor changes to the text and/or graphics, which... more Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal's standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.

Reviewed by members of the JBC Editorial Board. Edited by Chris Whitfield Numerous putative glyco... more Reviewed by members of the JBC Editorial Board. Edited by Chris Whitfield Numerous putative glycosyltransferases (GTs) have been identified using bioinformatic approaches. However, demonstrating the activity of these GTs remains a challenge. Here, we describe the development of a rapid in vitro GT-array screening platform for activity of GTs. GT-arrays are generated by cell-free in vitro protein synthesis and binding using microplates precoated with a N-terminal Halo-or a C-terminal GST-tagged GT-encoding plasmid DNA and a capture antibody. These arrays are then used for screening of transferase activities and the reactions are monitored by a luminescence GLO assay. The products formed by these reactions can be analyzed directly from the microplates by mass spectrometry. Using this platform, a total of 280 assays were performed to screen 22 putative fucosyltransferases (FUTs) from family GT37 (seven from Arabidopsis and 15 from rice) for activity toward five acceptors: non-fucosylated tamarind xyloglucan (TXyG), arabinotriose (Ara 3), non-fucosylated rhamnogalacturonan I (RG-I), and RG-II from the mur1-1 Arabidopsis mutant, and the celery RG-II monomer lacking Arap and MeFuc of chain B and L-Gal of chain A. Our screen showed that AtFUT2, AtFUT5, and AtFUT10 have activity toward RG-I, while AtFUT8 was active on RG-II. Five rice OsFUTs have XyG-FUT activity and four rice OsFUTs have activity toward Ara 3. None of the putative OsFUTs were active on the RG-I and RG-II. However, promiscuity toward acceptors was observed for several FUTs. These findings extend our knowledge of cell wall polysaccharide fucosylation in plants. We believe that in vitro GT-array platform provides a valuable tool for cell wall biochemistry and other research fields.

Cellulose and hemicellulose are the major structural β-glycan polysaccharides in cell walls of la... more Cellulose and hemicellulose are the major structural β-glycan polysaccharides in cell walls of land plants. They are characterized by a backbone of β-(1,3)-and/or β-(1,4)-linked sugars such as glucose, mannose, or xylose. The backbones of these polymers are produced by processive glycosyltransferases (GTs) called synthases having multiple transmembrane domains anchoring them to the membrane. Thus, they are among the most difficult membrane proteins to test in vitro and to purify. Recently, we developed an in vitro GT-array (i-GTray) platform and showed that non-processive type II membrane GTs could be produced via cell-free system in a soluble and active form and tested in this platform. To determine whether i-GT-ray platform is adequate for the production and testing of β-glycan synthases, we tested five synthases involved in cellulose, xyloglucan, (gluco)mannan, and β-(1,3)(1,4)-mixed-linkage glucan synthesis. Our results revealed unsuspected features of these enzymes. For example, all these synthases could be produced in a soluble and active form and are active in the absence of detergent or membrane lipids, and none of them required a primer for initiation of synthesis. All synthases produced ethanol-insoluble products that were susceptible to the appropriate hydrolases (i.e., cellulase, lichenase, mannanase). Using this platform, we showed that AtCslC4 and AtXXT1 interact directly to form an active xyloglucan synthase that produced xylosylated cello-oligosaccharides (up to three xylosyl residues) when supplied with UDP-Glc and UDP-Xyl. i-GTray platform represents a simple and powerful functional genomics tool for discovery of new insights of synthase activities and can be adapted to other enzymes.

including those for text and data mining, AI training, and similar technologies. mg L − 1), were ... more including those for text and data mining, AI training, and similar technologies. mg L − 1), were verified and confirmed using electrochemical simulations. Control experiments did not show degradation of PFOA in the absence of Pd-Ru nano-catalyst. The degradation in wastewater was obtained within 3 h with an efficiency of 98.5%. The electrochemical degradation products of PFOA were identified using Highresolution desalting paper spray mass spectrometry (DPS-MS) and collision-induced dissociation (CID) analysis. The results yielded C 2 F 5 COOH, C 3 F 7 COOH, and C 6 F 13 OH with dissociation losses of CF 2 O or CO 2. IMPACT introduces a novel nano-catalyst with high efficiency and a reliable capability that defluorinates strong C-F bonds that are components of recalcitrant organics in myriad environmental matrices.

Currently, glycopeptide quantitation is mainly based on relative quantitation due to absolute qua... more Currently, glycopeptide quantitation is mainly based on relative quantitation due to absolute quantitation requiring isotope-labeled or standard glycopeptides which may not be commercially available or are very costly and time consuming to synthesize. To address this grand challenge, coulometric mass spectrometry (CMS), based on the combination of electrochemistry (EC) and mass spectrometry (MS), was utilized to quantify electrochemically active glycopeptides without the need of using standard materials. In this study, we studied tyrosinecontaining glycopeptides, NYIVGQPSS(β-GlcNAc)TGNL-OH and NYSVPSS(β-GlcNAc)TGNL-OH, and successfully quantified them directly with CMS with a discrepancy of less than 5% between the CMS measured amount and the theoretical amount. Taking one step further, we applied this approach to quantify glycopeptides generated from the digestion of NIST mAb, a monoclonal antibody reference material. Through HILIC column separation, five N297 glycopeptides resulting from NIST mAb tryptic digestion were successfully separated and quantified by CMS for an absolute amount without the use of any standard materials. This study indicates the potential utility of CMS for quantitative proteomics research.

Peptide/protein quantitation using mass spectrometry (MS) is advantageous due to its high sensiti... more Peptide/protein quantitation using mass spectrometry (MS) is advantageous due to its high sensitivity. Traditional absolute peptide quantitation methods rely on making calibration curves using peptide standards or isotope-labelled peptide standards, which are expensive and take time to synthesize. A method which can eliminate the need for using standards would be beneficial. Recently, we developed coulometric mass spectrometry (CMS) which can be used to quantify peptides that are oxidizable (e.g., those containing tyrosine or tryptophan), without using peptide standard. The method is based on electrochemical oxidation of peptides followed by MS measurement of the oxidation yield. However, it cannot be directly used to quantify peptides without oxidizable residues. To extend this method for quantifying peptides/proteins in general, in this study, we adopted a derivatization strategy, in which a target peptide is first tagged with an electroactive reagent such as monocarboxymethylene blue NHS ester (MCMB-NHS ester), followed with quantitation by CMS. To illustrate the power of this method, we have analyzed peptides MG and RPPGFSPFR. The quantification error was less than 5%. Using RPPGFSPFR as an example, the quantitation sensitivity of the technique was found to be 0.25 pmol. Furthermore, we also used the strategy to quantify proteins cytochrome C and β-casein with an error of 2-26 %.