Science and technology of chrome tanning

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Hydrogen bonding and tautomeric equilibria in Schiff bases derived from 2-amino pyridines: electronic spectral evidence for substituent effects

Schiff bases of the type C6H3(R)(OH) CH = NC5H3N(Y)[where R = H, 3-OCH3, 5,6-benzo, 3-CHO-5-CH3,5-CI, 5-Br, 5-CH3, 4-CH3, 3-nitro and 5-nitro and Y=H, 3-CH3 4-CH3, 5-CH3, 6-CH3, 4,6-demethyl and 5-CI) have now been, synthesised and evidence sought for the electronic interaction between the substituents R (in the benzene ring) and Y (in the pyridine ring) in the molecule. The effects of substituents R and Y on the strength of hydrogen bond between OH and CH = N, is coupled to keloenamine ⇌ phenoliminc equilibrium. The groups which increase the acidity of the phenolic hydroxyl and the, basicity of the azomethine nitrogen facilitate quinonoid structures with characteristic visible absorption bands in the region 400-600 nm. In those compounds where R = 5,6-benzo, the intensity and the energy of band ~400 nm show a correlation with the electron releasing tendency of Y. Thus there appears an electronic communication between the substituents R and Y causing deviations from the generally accepted model for schiff base structures

Thermal and photochemical reactions of chromium (IV)-diperoxo complexes with organic substrates- evidence for hydroxylation of proline and phenol

The diperoxo complexes of chromium in an unusual oxidation number viz. 4, react with organic substrates such as proline and phenol to give bydroxyproline and o-benzoquinone as products respectively. The organic products were identified by electronic spectra as well as by their characteristic R1 values in thin layer chromatography using n-propanol-water(1:1v/v) mixure and chloroform as solvents for proline and phenol reaction products respectively. the studies reveal that the hydroperoxide radicals formed during the decomposition of Cr(IV)-diperoxo complexes give rise to the hydroxylation processes observed. The hydroxylation reactions are facilitated by light and yields of hydroxyproline upto 9% (from proline) have been obtained . The study presents one of the first examples of the use of Cr(IV) systems for biologically relevant processes such as hydroxylation

Major integrated environmental system for relocation of 540 tanneries in Kolkata City - a biggest environmental project of its kind in Asia

The tanning industry is one of the oldest and fastest growing industries in South and South East Asia. There are more than 3000 tanneries located in India with a total processing capacity of 700,000 tones of hides and skins per year. The wastewater discharge from these tanneries is about 100,000 cubic meters per day. More than 90% tanneries are in small and medium scale sector with processing capacities of less than 2-3 tons of hides/ skins per day

A life cycle assessment on the dehairing of rawhides : chemical treatment versus enzymatic recovery through solid state fermentation

The leather industry needs to switch from the traditional chemically based dehairing process to an environmentally friendly one so that the overall burdens to the environment are reduced. The primary goal of the work was thus to compare the chemical leather dehairing process to an enzymatically based one using the enzymes that are extracted after the application of solid state fermentation (SSF) on hair wastes generated after dehairing. The environmental burdens of the dehairing stage were determined using a life cycle assessment (LCA) approach by comparing the two aforementioned management scenarios. The first scenario was the commonly used technology in which hair is removed via a chemical process and then composted in open piles. This scenario included two subscenarios where hair waste is either incinerated or landfilled. In the second scenario, the proteolytic enzymes extracted during the SSF of the residual hair are used to dehair the new rawhides instead of chemicals. Industrial and laboratory data were combined with international databases using the SimaPro 8.0 LCA software to make comparisons. The environmental impacts associated with the enzymatic dehairing were significantly lower than the ones associated to the conventional chemical dehairing process. This difference is attributed to the impacts associated with the original production of the chemicals and to the electricity consumed in the conventional method. A sensitivity analysis revealed that the results are affected by the amounts of chemicals used during dehairing

Bioinformatics in crosslinking chemistry of collagen with selective cross linkers

<p>Abstract</p> <p>Background</p> <p>Identifying the molecular interactions using bioinformatics tools before venturing into wet lab studies saves the energy and time considerably. The present study summarizes, molecular interactions and binding energy calculations made for major structural protein, collagen of Type I and Type III with the chosen cross-linkers, namely, coenzyme Q₁₀, dopaquinone, embelin, embelin complex-1 & 2, idebenone, 5-O-methyl embelin, potassium embelate and vilangin.</p> <p>Results</p> <p>Molecular descriptive analyses suggest, dopaquinone, embelin, idebenone, 5-O-methyl embelin, and potassium embelate display nil violations. And results of docking analyses revealed, best affinity for Type I (- 4.74 kcal/mol) and type III (-4.94 kcal/mol) collagen was with dopaquinone.</p> <p>Conclusions</p> <p>Among the selected cross-linkers, dopaquinone, embelin, potassium embelate and 5-O-methyl embelin were the suitable cross-linkers for both Type I and Type III collagen and stabilizes the collagen at the expected level.</p

Enzymatic Depilation of Animal Hide: Identification of Elastase (LasB) from Pseudomonas aeruginosa MCM B-327 as a Depilating Protease

Conventional leather processing involving depilation of animal hide by lime and sulphide treatment generates considerable amounts of chemical waste causing severe environmental pollution. Enzymatic depilation is an environmentally friendly process and has been considered to be a viable alternative to the chemical depilation process. We isolated an extracellular protease from Pseudomonas aeruginosa strain MCM B-327 with high depilation activity using buffalo hide as a substrate. This 33 kDa protease generated a peptide mass fingerprint and de novo sequence that matched perfectly with LasB (elastase), of Pseudomonas aeruginosa. In support of this data a lasB mutant of MCM B-327 strain lacked depilatory activity and failed to produce LasB. LasB heterologously over-produced and purified from Escherichia coli also exhibited high depilating activity. Moreover, reintroduction of the lasB gene to the P. aeruginosa lasB mutant via a knock-in strategy also successfully restored depilation activity thus confirming the role of LasB as the depilating enzyme

Prognostic significance of CD44s expression in resected non-small cell lung cancer

<p>Abstract</p> <p>Background</p> <p>CD44s is a cell adhesion molecule known to mediate cellular adhesion to the extracellular matrix, a prerequisite for tumor cell migration. CD44s plays an important role in invasion and metastasis of various cancers. In the present study, we sought to determine whether CD44s is involved in clinical outcomes of patients with resected non-small cell lung cancer (NSCLC).</p> <p>Methods</p> <p>Using immunohistochemical staining, we investigated CD44s protein expression using tissue array specimens from 159 patients with resected NSCLC (adenocarcinoma (AC; <it>n </it>= 82) and squamous cell carcinoma (SCC; <it>n </it>= 77). Additionally, the immunoreactivity of cyclooxygenase (COX)-2 was also studied. The clinicopathological implications of these molecules were analyzed statistically.</p> <p>Results</p> <p>High CD44s expression was detected more frequently in NSCLC patients with SCC (66/72; 91.7%) than in those with AC histology (<it>P <</it>0.001). Additionally, high CD44s expression was significant correlated with more advanced regional lymph node metastasis (<it>P </it>= 0.021). In multivariate analysis of survival in NSCLC patients with AC histology, significant predictors were lymph node metastasis status (<it>P </it>< 0.001), high-grade tumor differentiation (<it>P = </it>0.046), and high CD44s expression (<it>P = </it>0.014). For NSCLC patients with SCC histology, the significant predictor was a more advanced tumor stage (<it>P = </it>0.015). No significant association was found between CD44s and clinical outcome (<it>P </it>= 0.311).</p> <p>Conclusions</p> <p>High CD44s expression was a negative prognostic marker with significance in patients with resected NSCLC, particularly those with AC histology, and was independent of tumor stage.</p

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead