Cochin University of Science and Technology

About: Cochin University of Science and Technology is a education organization based out in Kochi, Kerala, India. It is known for research contribution in the topics: Thin film & Natural rubber. The organization has 5382 authors who have published 7690 publications receiving 103827 citations. The organization is also known as: CUSAT & Cochin University.

Odd–even oscillations in structural and optical properties of gold clusters

Abstract: Density Functional Theory (DFT) calculations suggests odd–even oscillations in structural, geometrical and optical properties of neutral Au-clusters ( n = 2–20). Such odd–even oscillations are understood on the basis of the presence of SOMO in the case of the odd-membered clusters. An analysis of the Mulliken spin-density shows that the negative charges are localized on the edge-atoms on the clusters while the core-atoms are electron deficient. Interestingly, the color of the clusters also shows an odd–even oscillation. A rule similar to the Woodward–Fieser rules is proposed for predicting the average red-shift in visible spectra in these nanoclusters.

Mechanistic Study for the Facile Oxidation of Trimethoprim on a Manganese Porphyrin Incorporated Glassy Carbon Electrode

Abstract: The electrocatalysis of [5,10,15,20-tetrakis(4-methoxyphenyl)porphyrinato]Mn(III)chloride (TMOPPMn(III)Cl) toward the oxidation of trimethoprim was investigated by electrochemical and computational methods. Voltammetric analysis demonstrates the ability of TMOPPMn(III)Cl to act as an electrocatalyst for the oxidation of trimethoprim. DFT calculations were performed at the B3LYP level to detect the site of oxidation as well as to survey the role of manganese porphyrin in the facile oxidation of trimethoprim. Quantum chemical calculations affirm that the deprotonation of NH2 attached to C4 is more energetically favorable as compared to deprotonation of the C2 amino group. Also, the deprotonation of trimethoprim in the TMOPPMn(III)Cl-catalyzed reaction results in the formation of a more stable anion as compared to the uncatalyzed reaction. Atoms in molecule (AIM) analysis and natural bond orbital (NBO) analysis also substantiate the utility of TMOPPMn(III)Cl in trimethoprim oxidation by confirming the coordi...

Metastatic melanoma: pretreatment contrast-enhanced CT texture parameters as predictive biomarkers of survival in patients treated with pembrolizumab

Abstract: To determine whether texture analysis features on pretreatment contrast-enhanced computed tomography (CT) images can predict overall survival (OS) and progression-free survival (PFS) in patients with metastatic malignant melanoma (MM) treated with an anti-PD-1 monoclonal antibody, pembrolizumab. This institutional-approved retrospective study included 31 patients with metastatic MM treated with pembrolizumab. Texture analysis of 74 metastatic lesions was performed on CT scanners obtained within 1 month before treatment. Mean gray-level, entropy, kurtosis, skewness, and standard deviation values were derived from the pixel distribution histogram before and after spatial filtration at different anatomic scales, ranging from fine to coarse. Lasso penalized Cox regression analyses were performed to identify independent predictors of OS and PFS. Median OS and PFS were 357 days (range 42–1355) and 99 days (range 35–1185), respectively. Skewness at coarse texture scale (SSF = 6; HR (CI 95%) = 6.017 (1.39, 26.056), p = 0.016), Response evaluation criteria in solid tumors (RECIST) conclusion (HR (CI 95%) = 3.41 (1.17, 9.89), p = 0.024), and body weight (HR (CI 95%) = 0.96 (0.92, 0.995), p = 0.026) were independent predictors of OS. Skewness at coarse texture scale (SSF = 6; HR (CI 95%) = 4.55 (1.46, 14.13), p = 0.0089) and RECIST conclusion (HR (CI 95%) = 10.63 (3.11, 36.29), p = 0.00016) were independent predictors of PFS. Skewness values above − 0.55 at coarse texture scale were significantly associated with both lower OS and lower PFS after administration of pembrolizumab. Pretreatment CT texture analysis–derived tumor skewness may act as predictive biomarker of OS and PFS in patients with metastatic MM treated with pembrolizumab. • Pretreatment skewness at coarse texture scale in metastases from malignant melanoma was an independent predictor of overall survival and progression-free survival. • Skewness values above −0.55 at coarse texture scale were significantly associated with both lower OS and lower PFS after administration of pembrolizumab. • In patients with metastatic MM, texture analysis performed on pretreatment CT may act as a useful tool to select the best candidates for pembrolizumab therapy.

Nearshore sediment characteristics and formation of mudbanks along the Kerala coast, southwest India

Abstract: In order to gain insight into the formation dynamics of mudbanks off the Kerala coast of India, extensive surveying of the nearshore bathymetry along with sediment characterization was undertaken. The textural and geotechnical properties of the surficial sediments of a mudbank were determined during pre-monsoon, monsoon, and post-monsoon periods. The mudbank sediments were clayey silts with high water and organic carbon contents, high Atterberg limits, and low bulk density, and therefore very susceptible to entrainment. During the monsoon, the mudbank regime was characterised by enhanced turbidity and a benthic fluff layer, triggered by the increasing swell of the early monsoon period. Re-suspension exposed a more consolidated, previously sub-bottom, layer which exhibited lower water content and greater shear strength than the pre-monsoon seabed. Texturally, the monsoon seabed was similar to the pre-monsoon seabed, with the same modal grain size, but the proportions of sand and coarse silt increased nearshore, while the proportions of fine and very fine silt increased offshore. There was a seaward-fining textural gradient at all times, but this became pronounced during the monsoon period. Paradoxically, the monsoonal seabed displayed greatly reduced wet bulk density. It is hypothesized that this was due to the presence of gas, probably methane, in the sediments (while the pre-monsoon sediments were fully saturated, the monsoon sediments were only 83% saturated). We speculate that the gas was forced into the surficial sediments either by wave pumping (at the onset of the monsoon) or by seaward-flowing subbottom freshwater (derived from monsoonal rains). With the waning of the monsoon, the benthic fluid mud layer rapidly disappeared and the seabed returned to its pre-monsoon state as suspended sediments were redeposited. The mudbank regime is therefore essentially an in situ phenomenon. It is suggested that the mudbanks are palimpsest, marshy, lagoonal deposits, rich in organic matter and derived gas, that were submerged after a marine transgression. The surficial sediment is annually entrained during the monsoon, but erosion is limited by the formation of the benthic fluid mud layer, which attenuates wave generated turbulence. Although some fine sediment disperses alongshore and offshore, most is returned to the seabed as the monsoon declines.