Department of Chemistry

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The role of a room temperature ionic liquid (RTIL, [pmim][Br]) on the size and conformational dynamics of a protein, horse heart cytochrome c (Cyt C) in its native, molten globule (MG-I and II), and unfolded states is studied using fluorescence correlation spectroscopy (FCS). For this purpose, the protein was covalently labeled by a fluorescent dye, Alexa Fluor 488. It is observed that the addition of the RTIL leads to an increase in the hydrodynamic radius (rH) of the protein, Cyt C in the native or MG-I state. In contrast, the addition of RTIL causes a decrease in the size (hydrodynamic radius, rH) of Cyt C unfolded by GdnHCl or MG-II state. The decrease in size indicates the formation of a relatively compact structure. We detected two types of conformational relaxation of the protein. The shorter relaxation time component (∼3-5.5 μs) corresponds to the protein folding or intrachain contact formation, while the relatively longer time component (∼63-122 μs) may be assigned to the motion of the protein side chains or concerted chain dynamics. The burst integrated fluorescence lifetime histograms indicate that the increase in size of the protein is accompanied by an increase in the contribution of the shorter component (∼0.3-0.4 ns) with a concomitant decrease of the contribution of the longer component (∼2.8-3.6 ns). An opposite trend is observed during the decrease in size of the protein. © 2012 American Chemical Society.

World University root node

Journal of Physical Chemistry B

Role of ionic liquid on the conformational dynamics in the native, molten globule, and unfolded states of cytochrome C: A fluorescence correlation spectroscopy study

The effect of two room-temperature ionic liquids (RTILs) on the diffusion of three fluorescent dyes in the gel phase of a triblock copolymer, (PEO) 20-(PPO)70-(PEO)20 [Pluronic P123; poly ethylene oxide (PEO), poly propylene oxide (PPO)], was studied by using fluorescence correlation spectroscopy (FCS). We used three dyes, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), coumarin 480 (C480), and coumarin 343 (C343). By field-emission scanning electron microscopy (FESEM), it was observed that the macroscopic structure of the P123 gel remained unaffected upon addition of RTIL. In the absence of RTIL, the diffusion coefficient (Dt) of the hydrophobic dye DCM (1 μm 2s-1 at the core) is smaller than that of the other two hydrophilic dyes (7 μm2s-1 for C480 and C343). On addition of RTIL, the Dt values of all of the dyes increase, indicating a decrease in local viscosity (ηeff). The ηeff of the core of the RTIL-P123 gel estimated from the D t of DCM is lower than that of both the P123 gel (at the core η=90 cP) and RTIL (η=110 cP). It is shown that the RTIL affects the structure of the gel by modifying the size of the micellar aggregates and by penetrating the core. © 2012 Wiley-VCH Verlag GmbH&amp; Co. KGaA, Weinheim.

ChemPhysChem

Effect of ionic liquid on diffusion in P123 Gel: Fluorescence correlation spectroscopy

Picosecond spectroscopy under a confocal microscope is employed to study solvation dynamics of coumarin 153 (C153) inside a single giant lipid vesicle (1,2-dilauroyl-sn-glycero-3-phosphocholine, DLPC) of diameter 20 μm. Fluorescence correlation spectroscopy (FCS) indicates that the diffusion coefficient (D t) of the probe (coumarin153, C153) in the immobilized vesicle displays a wide distribution from ∼3 to 21 μm 2 s -1. The distribution of D t suggests that the microenvironment of the probe (C153) is highly heterogeneous and the local friction is different for probe molecules in different regions. The values of D t is significantly smaller than that for the same dye in bulk water (550 μm 2 s -1). This suggests that the probe is located in the interface or membrane region rather than in the water pool of the vesicle. The solvation time of C153 in different regions of the lipid vesicle varies between 750 to 1200 ps. This result clearly shows that a confocal microscope is able to resolve the spatial heterogeneity in local friction (i.e., D t) and solvation dynamics within a lipid vesicle. © 2012 American Chemical Society.

Langmuir

Solvation dynamics under a microscope: Single giant lipid vesicle

Aim and Objective: To evaluate the effect of penile block vs caudal epidural on the quality of analgesia and surgical outcome following hypospadias repair. Background: Intraoperative penile engorgement because of caudal epidural may result in tension on surgical sutures and alter surgical outcome. Methods: Fifty-four ASA I and II children were randomly allocated to group P (penile block, 0.25\% bupivacaine, 0.5 mg center dot kg-1; n = 27) and group C (caudal epidural, 0.25\% bupivacaine, 0.5 ml center dot kg-1; n = 27), respectively. Quality of analgesia was assessed by visual analog scale (VAS) score recorded at 0, 0.5, 3, 6, 12, 24 h, and once a day for the next 4 days. Duration of analgesia was calculated from the institution of block to the first analgesic demand by child or VAS > 5. Total morphine consumption in the first 48 h and oral paracetamol consumption till 5th day were recorded. Children were regularly followed up in their respective outpatient clinic for early or late complications. Results: In group P, lower mean VAS scores were seen from 0.5 h after surgery till day 3 and analgesia lasted for significantly longer duration (82 min) when compared with caudal epidural, P < 0.001. Incidence of urethral fistula formation after primary hypospadias repair was 19.2\%, and all had received caudal epidural. An increase of 27\% in penile volume from baseline value was observed 10 min after caudal epidural placement, P < 0.05. Conclusion: Penile block provided better analgesia when compared with caudal epidural in children undergoing primary hypospadias repair. Postoperative urethral fistula formation was more likely in children who received caudal epidural.

PEDIATRIC ANESTHESIA

Surgical outcome in children undergoing hypospadias repair under caudal epidural vs penile block

Positioning the parturient from supine to the left lateral tilt position (supine-to-tilt) may not effectively displace the gravid uterus, but turning from the left lateral position to the left lateral tilt position (left lateral-to-tilt) may keep the gravid uterus displaced and prevent aortocaval compression. Fifty-one full-term parturients were randomly placed in the left lateral position, supine-to-tilt and left lateral-to-tilt positions using a Crawford wedge. Femoral vein area, femoral vein velocity, femoral artery area, pulsatility index, resistance index and right arm mean arterial blood pressure and heart rate were recorded. Our results showed a lower mean (SD) femoral vein area (82.2 (14.9) vs 96.2 (16.4) mm2), a lower pulsatility index (3.83 (1.3) vs 5.8 (2.2)), a lower resistance index (0.93 (0.06) vs 0.98 (0.57)), a higher femoral artery area (33.3 (3.8) vs 30.9 (4.4) mm2) and a higher femoral vein velocity (7.9 (1.2) vs 6.1 (1.6) cm.s-1) with left lateral-to-tilt when compared with supine-to-tilt (all p < 0.001). Our results suggest that moving a full-term parturient from the full left lateral to the lateral tilt position may prevent aortocaval compression in full-term parturients more efficiently than when positioning the parturient from a supine to left lateral tilt position.

ANAESTHESIA

Effect of positioning from supine and left lateral positions to left lateral tilt on maternal blood flow velocities and waveforms in full-term parturients

Cancer prognosis prediction improves the quality of treatment and increases the survivability of the patients. Conventional methods of cancer prediction deal with single class by limiting the prognosis prediction to one response variable. The SEER Public Use cancer database has more prominent variables that support better prediction approach. The objective of this paper is to find the prominent labels from cancer databases and use them in a multi-class environment. The implementation consist of three phases namely, pre-processing, prominent label identification and multi-label classification. Breast, Colorectal and Respiratory Cancer Data sets have been used for the experimentation. Also random samples from all three data sets are generated to form a mixed cancer data. Patient survival, number of primaries and age at diagnosis are the prominent labels identified from others using the Decision tree, Naive Bayes and KNN algorithms. The three prominent labels have been tested using multi-label RAkEL algorithm to find the relations between them. The results of the empirical study are comparatively better than the traditional way of cancer prediction.

Prominent Label Identification and Multi-label Classification for Cancer Prognosis Prediction

Coumarins C-153, C-480, and C-1 formed 1:2 (guest:host) complexes ith a watersoluble cavitand having eight carboxylic acid groups (OA) in aqueous borate buffer solution. The complexes were photoexcited in the presence of electron acceptors (methyl viologen, MV 2+, or TiO 2) to probe the possibility of electron transfer between a donor and an acceptor physically separated by a molecular wall. In solution at basic pH, the dication MV 2+ was associated to the exterior of the complex C-153@OA 2, as suggested by diffusion constants (?1.2 × 10- 6 cm2/s) determined by DOSY NMR. The fluorescence of C-153@OA 2 was quenched in the presence of increasing amounts of MV 2+ and Stern-Volmer plots of Io/I and ?o/? vs [MV 2+] indicated that the quenching was static. As per FT-IR-ATR spectra, the capsule C-153@OA 2 was bound to TiO 2 nanoparticle films. Selective excitation (?exc = 420) of the above bound complex resulted in fluorescence quenching. When adsorbed on insulating ZrO 2 nanoparticle films, excitation of the complex resulted in a broad fluorescence spectrum centered at 500 nm and consistent with C-153 being within the lipophilic capsule interior. Consistent with the above results, colloidal TiO 2 quenched the emission while colloidal ZrO 2 did not. © 2012 American Chemical Society.

Photoinduced electron transfer across a molecular wall: Coumarin dyes as donors and methyl viologen and TiO 2 as acceptors

A new carbazole-based 90° dipyridyl donor 3,6-di(4-pyridylethynyl) carbazole (L) containing carbazole-ethynyl functionality is synthesized in reasonable yield using the Sonagashira coupling reaction. Multinuclear NMR, electrospray ionization-mass spectrometry (ESI-MS), including single crystal X-ray diffraction analysis characterized this 90° building unit. The stoichiometry combination of L with several Pd(II)/Pt(II)-based 90° acceptors (1a-1d) yielded [2 + 2] self-assembled metallacycles (2a-2d) under mild conditions in quantitative yields [1a = cis-(dppf)Pd(OTf) 2; 1b = cis-(dppf)Pt(OTf) 2; 1c = cis-(tmen)Pd(NO 3) 2; 1d = 3,6-bis{trans-Pt(C=C)(PEt 3) 2(NO 3)} carbazole]. All these macrocycles were characterized by various spectroscopic techniques, and the molecular structure of 2a was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of ethynyl functionality to the carbazole backbone causes the resulted macrocycles (2a-2d) to be π-electron rich and thereby exhibit strong emission characteristics. The macrocycle 2a has a large internal concave aromatic surface. The fluorescence quenching study suggests that 2a forms a ∼1:1 complex with C 60 with a high association constant of K sv = 1.0 × 10 5 M -1. © 2012 American Chemical Society.

Inorganic Chemistry

Coordination-driven self-assembly of 2D-metallamacrocycles using a new carbazole-based dipyridyl donor: Synthesis, characterization, and C 60 binding study

Coordination-driven self-assembly of binuclear half-sandwich p-cymene ruthenium(II) complexes [Ru 2(μ-η 4-C 2O 4)(MeOH) 2(η 6-pcymene) 2](O 3SCF 3) 2 (1a) or [Ru 2(μ-η 4-N,N'-diphenyloxamidato)(MeOH) 2(η 6-p-cymene) 2](O 3SCF 3) 2 (1b) separately with an imidazole-based tetratopic donor L in methanol affords two tetranuclear metallamacrocycles 2a and 2b, respectively. Conversely, the similar combination of L with 2,5-dihydroxy-1,4- benzoquinonato (dhbq) bridged binuclear complex [Ru 2(μ- η 4-C 6H 2O 4)(MeOH) 2(η 6-p-cymene) 2](O 3SCF 3) 2 (1c) in 1:2 molar ratio resulted in an octanuclear macrocyclic cage 2c. All the selfassembled macrocycles 2a-2c were isolated as their triflate salts in high yields and were characterized fully by multinuclear ( 1H, 13C and 19F) NMR, infrared (IR) and electrospray ionization mass spectrometry (ESIMS). In addition, the molecular structure of macrocycle 2a was established unequivocally by single-crystal X-ray diffraction analysis and adopts a tetranuclear rectangular geometry with the dimensions of 5.53 Å × 12.39 Å. Furthermore, the photo-and electrochemical properties of these newly synthesized assemblies have been studied by using UV-vis absorption and cyclic voltammetry analysis. © 2012 Shanmugaraju et al.

Fulltext

Beilstein Journal of Organic Chemistry

Self-assembly of Ru 4 and Ru 8 assemblies by coordination using organometallic Ru(II) 2 precursors: Synthesis, characterization and properties

We present a new concept for studies of the kinetics of fast gas-liquid reactions. The strategy relies on the microfluidic generation of highly monodisperse gas bubbles in the liquid reaction medium and subsequent analysis of time-dependent changes in bubble dimensions. Using reactions of CO 2 with secondary amines as an exemplary system, we demonstrate that the method enables rapid determination of reaction rate constant and conversion, and comparison of various binding agents. The proposed approach addresses two challenges in studies of gas-liquid reactions: a mass-transfer limitation and a poorly defined gas-liquid interface. The proposed strategy offers new possibilities in studies of the fundamental aspects of rapid multiphase reactions, and can be combined with throughput optimization of reaction conditions. © 2011 American Chemical Society.