A5073231395- Advanced Chemical Physics Studies
- Astrophysics and Star Formation Studies
- Photochromic and Fluorescence Chemistry
- Astro and Planetary Science
- Atomic and Molecular Physics
- Click Chemistry and Applications
- Molecular Spectroscopy and Structure
- Photoreceptor and optogenetics research
- Carbohydrate Chemistry and Synthesis
- Atmospheric Ozone and Climate
- Chemical Synthesis and Analysis
- Mass Spectrometry Techniques and Applications
- Advanced Combustion Engine Technologies
- Inorganic Fluorides and Related Compounds
- Glycosylation and Glycoproteins Research
- Spectroscopy and Quantum Chemical Studies
- Biochemical and Structural Characterization
- Ion-surface interactions and analysis
- Fullerene Chemistry and Applications
- Origins and Evolution of Life
- Bone health and treatments
- Synthetic Organic Chemistry Methods
- Bacteriophages and microbial interactions
- Combustion and flame dynamics
- Laser-Matter Interactions and Applications
Vellore Institute of Technology University
2019-2025
Centre National de la Recherche Scientifique
2009-2020
Institut des Sciences Moléculaires
2011-2020
Institut de Physique de Rennes
2008-2020
Université de Rennes
2009-2020
Weizmann Institute of Science
2013-2018
Kiel University
2011-2016
Hebrew University of Jerusalem
2015-2016
Clinical Research Center Kiel
2015
Université de Bordeaux
2011-2012
We present a novel chemical database for gas-phase astrochemistry. Named the KInetic Database Astrochemistry (KIDA), this consists of reactions with rate coefficients and uncertainties that will be vetted to greatest extent possible. Submissions measured calculated are welcome, studied by experts before inclusion into database. Besides providing kinetic information interstellar medium, KIDA is planned contain such data planetary atmospheres circumstellar envelopes. Each year, subset in...
Abstract The surface recognition in many biological systems is guided by the interaction of carbohydrate‐specific proteins (lectins) with carbohydrate epitopes (ligands) located within unordered glycoconjugate layer (glycocalyx) cells. Thus, for recognition, respective ligand has to reorient a successful matching event. Herein, we present first time model system, which only orientation altered controlled manner without changing quality itself. key this orientational control embedding into an...
We determined absolute rate coefficients for the recurrent fluorescence (RF) process in C6– anions at excitation energies above adiabatic electron attachment energy of 4.18 eV. The experiment was performed by extracting ions from a sputter ion source and storing them bent electrostatic beam trap. After 1 s storage, during which cooled down to temperatures close room temperature, they were excited short laser pulse neutralization due vibrational autodetachment (VAD) measured as function time...
Bacterial adhesion to glycosylated surfaces is a key issue in human health and disease. Inhibition of bacterial by suitable carbohydrates could lead an anti‐adhesion therapy as novel approach against infections. A selection five α‐mannosides has been evaluated inhibitors the polysaccharide mannan, well surface live HT‐29 cells. Cell toxicity studies were performed identify therapeutic window for potential vivo‐application tested carbohydrates. previously published mannosidic squaric acid...
Azobenzene glycoconjugates can be switched between two isomeric states, E and Z, to change the spatial orientation of conjugated carbohydrate ligands. Mono-, di- trivalent azobenzene were synthesized using click chemistry their photochromic properties determined. Multivalency effects observed in photoisomerisation.
Abstract Unique black coatings were observed in the inner wall of pottery shreds excavated from Keeladi, Tamilnadu, India. Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy used to understand nature coating. The analysis revealed presence single, multi-walled carbon nanotubes layered sheets average diameter single-walled nanotube found be about 0.6 ± 0.05 nm. This is lowest among reported artefacts so far close theoretically predicted value (0.4 nm)....
<title>Abstract</title> Organic Residue Analysis (ORA) has emerged as a pivotal technique in archaeology, offering direct molecular insights into past societies' dietary practices and culinary traditions. By analyzing the lipids, proteins, other organic compounds preserved within porous matrix of ancient pottery, researchers can reconstruct types foods consumed, processing methods employed, even gain glimpses early agricultural animal husbandry practices. Here, we present groundbreaking...
The direct infrared (IR) absorption spectrum of benzene dimer formed in a free-jet expansion was recorded the 3.3 μm region for first time. This has led to observation C–H stretching fundamental mode ν13 (B1u), which is both IR and Raman forbidden monomer. Moreover, allowed ν7 (E2g) been observed as well. These two modes were found be red-shifted along with ν20 (E1u) mode, previously reported by Erlekam et al. [Erlekam; Frankowski; Meijer; Gert von Helden J. Chem. Phys.2006, 124, 171101],...
Abstract The study of bacterial adhesion is crucial to our understanding infection processes as well for the development antiadhesives. Here we have investigated new nanodiamond glycoconjugates intended inhibit type 1 fimbriated E. coli bacteria. For conjugation saccharides and nanodiamond, thiourea‐bridging was employed, a method that has not been used before in derivatization. Amino‐prefunctionalized diamond nanoparticles were prepared employing aromatic diazonium salts reacted with...
Abstract Azobenzene linker molecules can be utilized to control peptide/protein function when they are ligated appropriately spaced amino acid side chains of the peptide. This is because photochemical E / Z isomerization azobenzene NN double bond allows switch peptide conformation between folded and unfolded. In this context, we have introduced carbohydrate‐functionalized derivatives in order advance biocompatible properties linkers. Chloroacetamide‐functionalized O ‐allylated carbohydrate...
The building blocks of life, amino acids, are believed to have been synthesized in the extreme conditions that prevail space, starting from simple molecules containing hydrogen, carbon, oxygen and nitrogen. However, fate role acids when they subjected similar processes largely remain unexplored. Here we report, for first time, shock processed tend form complex agglomerate structures. Such structures formed on timescales about 2 ms due impact induced heating subsequent cooling. This discovery...
In order to allow spatial and temporal control of carbohydrate-specific bacterial adhesion, it has become our goal synthesise azobenzene mannosides as photoswitchable inhibitors type 1 fimbriae-mediated adhesion E. coli. An mannobioside 2 was prepared its photochromic properties were investigated. The E→Z isomerisation found be highly effective, yielding a long-lived (Z)-isomer. Both isomers, E Z, show excellent water solubility tested mannoside-specific in solution. Their inhibitory potency...
Abstract Photoisomerizable glyco‐SAMs (self‐assembled monolayers), utilizing synthetic azobenzene glycoside derivatives were fabricated. The ultimate goal of this project is to assay the influence 3D arrangement sugar ligands on cell adhesion, and eventually make adhesion photoswitchable. However, it a prerequisite for any biological study spatial conditions carbohydrate recognition, that photoisomerization surface molecules can be verified. Here, we employed IRRAS XPS spectroscopically...
Isomers of CAl4Mg and CAl4Mg− have been theoretically characterized for the first time. The most stable isomer both neutral anion contain a planar tetracoordinate carbon (ptC) atom. Unlike isovalent CAl4Be case, which contains pentacoordinate atom as global minimum geometry, replacing beryllium with magnesium makes ptC due to increased ionic radii magnesium. However, it is relatively easier conduct experimental studies CAl4Mg0/− toxic. While molecule containing follows 18 valence electron...
Abstract Spatial orientation of carbohydrates is a meaningful parameter in carbohydrate recognition processes. To vary sugars with temporal and spatial resolution, photosensitive glycoconjugates favorable photochromic properties appear to be opportune. Here, series azobenzene glycosides were synthesized, employing glycoside synthesis Mills reaction, allow “switching” by reversible E / Z isomerization the N=N double bond. Their tested effects substitution as well effect anomeric configuration...
Dissociation pathways of the global minimum geometry Si2C5H2 with a planar tetracoordinate carbon (ptC) atom, 2,7-disilatricyclo[4.1.0.01,3]hept-2,4,6-trien-2,7-diyl (1), have been theoretically investigated using density functional theory and coupled-cluster (CC) methods. Si-C bond connected to ptC atom leads formation 4,7-disilabicyclo[4.1.0]hept-1(6),4(5)-dien-2-yn-7-ylidene (4) through single transition state. C-C an intermediate two identical states back 1 itself. Simultaneous breaking...
Fullerene C 60 is one of the most iconic forms carbon found in interstellar medium (ISM). The chemistry carbon-rich components, including fullerenes, driven by a variety energetic processes UV and X-ray irradiation, cosmic-ray (CR) bombardment, electron impact, shock waves. These violent events strongly alter particle phase lead to release new molecular species gas phase. Only few experimental studies on processing cosmic analogs have been conducted so far. We explored laboratory destruction...
Abstract In vielen biologischen Systemen wird die Erkennung von Oberflächen durch Wechselwirkung Kohlenhydrat‐spezifischen Proteinen (Lektinen) mit den Kohlenhydratepitopen (Liganden) der ungeordneten Glycokonjugatschicht (Glycokalyx) Zellen gesteuert. Damit es zu einer erfolgreichen Anbindung kommt, müssen sich diese Liganden geeignet im Raum orientieren. Wir stellen zum ersten Mal ein Modellsystem vor, in dem Orientierung auf Oberfläche kontrolliert variiert wird, ohne dabei ihre...
Absolute photoabsorption cross sections of negatively charged tetra-atomic aluminum clusters have been measured for photon energies between 1.8 and 2.7 eV. The experiment used the depletion technique in combination with an electrostatic ion-beam trap, which ${{\mathrm{Al}}_{4}}^{\ensuremath{-}}$ ions produced a sputter ion source were stored 90 ms before being subjected to short laser pulse. Moreover, competition one-atom fragmentation electron emission laser-excited has measured. These...
The interaction of intense ultrafast laser pulses with atomic ${\mathrm{F}}^{\ensuremath{-}}$ and molecular $\mathrm{S}{{\mathrm{F}}_{6}}^{\ensuremath{-}}$ anions is directly compared. double-detachment mechanism investigated by a systematic variation peak intensity, polarization ellipticity, pulse shape. For both systems, the observed weak ellipticity dependence not consistent rescattering-based mechanism. A saturation intensity...
Abstract More than 70 molecules of varied nature have been identified in the envelopes carbon‐rich stars through their spectral fingerprints microwave or far infrared regions. Many them are carbon chain and radicals, a significant number unique to circumstellar medium. The determination relevant laboratory kinetics data is critical keep up with development high spatial resolution observations refinement chemical models. Neutral–neutral reactions CN radical unsaturated hydrocarbons could be...
Isomerization and carbon chemistry in the gas phase are key processes many scientific studies. Here we report on isomerization process from linear [Formula: see text] to its monocyclic isomer. ions were trapped an electrostatic ion beam trap then excited with a laser pulse of precise energy. The neutral products formed upon photoexcitation measured as function time after pulse. It was found using statistical model that, although system is above barrier energy, actual conformation takes place...
Abstract The Mitsunobu reaction has been revisited to join hydroxyazobenzene and mannose derivatives supply photoswitchable glycoconjugates. These are suited modulating controlling carbohydrate‐lectin interactions, as well switching bacterial adhesion surfaces. Employing in a protocol, free led mixture of azobenzene pyranosides furanosides. Protected reducing can give good yields β‐ D ‐mannopyranoside, unprotected alkyl α‐ ‐mannosides be converted 6‐ O ‐azobenzene‐modified glycosides single...