BHU Institutional Repository :: Browsing by Author "Singh, Sachin Kumar"

Browsing by Author "Singh, Sachin Kumar"

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Advances in Lung Cancer Treatment Using Nanomedicines
(American Chemical Society, 2023) Sharma, Akshansh; Shambhwani, Devanshi; Pandey, Sadanand; Singh, Jay; Lalhlenmawia, Hauzel; Kumarasamy, Murali; Singh, Sachin Kumar; Chellappan, Dinesh Kumar; Gupta, Gaurav; Prasher, Parteek; Dua, Kamal; Kumar, Deepak
Carcinoma of the lungs is among the most menacing forms of malignancy and has a poor prognosis, with a low overall survival rate due to delayed detection and ineffectiveness of conventional therapy. Therefore, drug delivery strategies that may overcome undesired damage to healthy cells, boost therapeutic efficacy, and act as imaging tools are currently gaining much attention. Advances in material science have resulted in unique nanoscale-based theranostic agents, which provide renewed hope for patients suffering from lung cancer. Nanotechnology has vastly modified and upgraded the existing techniques, focusing primarily on increasing bioavailability and stability of anti-cancer drugs. Nanocarrier-based imaging systems as theranostic tools in the treatment of lung carcinoma have proven to possess considerable benefits, such as early detection and targeted therapeutic delivery for effectively treating lung cancer. (Figure presented) Several variants of nano-drug delivery agents have been successfully studied for therapeutic applications, such as liposomes, dendrimers, polymeric nanoparticles, nanoemulsions, carbon nanotubes, gold nanoparticles, magnetic nanoparticles, solid lipid nanoparticles, hydrogels, and micelles. In this Review, we present a comprehensive outline on the various types of overexpressed receptors in lung cancer, as well as the various targeting approaches of nanoparticles. © 2022 The Authors.
Concept and role of immunomodulatory medicinal plants used in Ayurvedic health care system
(EnPress Publisher, LLC, 2024) Sachin; Kumar, Vineet; Sharma, Mohit; Vaishnavi; Chaudhary, Priyanka; Singh, Saurabh; Sudhakar, Kalvatala; Kumar, Bimlesh; Pandey, Narendra Kumar; Singh, Sachin Kumar; Choudhary, Anand Kumar; Baghel, Dileep Singh
The statement "prevention is better than cure" and its applications is not a new for Ayurvedic health care system. The statement defines the aim and objectives of Ayurvedic health care system in a nutshell "swasthasya swasthya rakshanam aaturasya vikara prashamanam". The immune system is certainly considered one of our most discreet biological systems withinside the body. Immunizations may be obtained by us actively or passively. Active immunization includes stimulating with an antigen to generate immunological defenses against a destiny exposure, rather than passive vaccination, which includes administering antibodies to someone who has already been exposed to an antigen. Both plant and animal sources produce immunomodulatory effects to boost the body’s immunological reactivity against infections by engaging the non-specific immune system. Herbal immunomodulators are substances that either activate or suppress innate and adaptive immune responses in the body. Different ailments including allergies, asthma, rheumatoid arthritis, cancer, and other infectious disorders are caused by immune system failure. Therefore, regulating the many infectious illnesses requires significant immune response modification. Global scientific study is currently focused on how various medicinal plant components might alter the immune system. Numerous Indian and "Rasayana" and medicinal plants may have immunomodulatory characteristics. Some of these plants are Tinospora cordifolia, Morus alba, Acacia catechu, Allium sativum, and Mangifera indica. There are many more that are still undiscovered and offer space for greater study. © 2024 by author(s).
Effect of alkoxy chain density on the mesogenic properties of aroylhydrazone based liquid crystals: synthesis, characterisation, photophysical and gelation behaviour
(Taylor and Francis Ltd., 2020) Kanth, Priyanka; Singh, Hemant Kumar; Kumar, Vijay; Singh, Sachin Kumar; Rao, D. S. Shankar; Prasad, S. Krishna; Singh, Bachcha
Three series of ester linkage containing aroylhydrazone based compounds have been synthesised where density and length of alkoxy chains are varied sequentially at ester end, keeping amide end of the molecule the same to investigate the effect of alkoxy chain density. The series of the compounds with single alkoxy chain at 4- position at ester terminal show nematic mesophase. The series with two alkoxy chains at 3- and 5- positions exhibit columnar rectangular mesophase and the series with three alkoxy chains at 3-, 4- and 5- positions show columnar oblique mesophase. It was observed that increasing the number of alkoxy chains at ester terminal, self-assembly of molecules changes and leads to a change from nematic to columnar mesophase and also significant enhancement in the mesomorphic range. Temperature dependent Raman studies confirm the presence of intermolecular hydrogen bonding which assist the self-assembly and gelation properties of molecules. All the series show similar photophysical properties despite the fact that the series vary in their molecular structures. Representative compounds of each series exhibited gelation in hydrocarbon solvents. FESEM images of the gels showed interwoven network of nanofibers of several micrometres length. These supergelators may be good candidates for applications in electronic devices. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Effect of regioisomerism on the self-assembly, photophysical and gelation behavior of aroylhydrazone based polycatenars: Synthesis and characterization
(Elsevier B.V., 2019) Kanth, Priyanka; Singh, Hemant Kumar; Kumar, Vijay; Singh, Sachin Kumar; Rao, D.S. Shankar; Prasad, S. Krishna; Singh, Bachcha
In this paper we report five series of aroylhydrazone based polycatenars differing from each other in number and position of alkoxy chains on one end of the core; keeping other end the same. A systematic variation in the structures was carried out to understand the effect of position and chain length on the mesophase behavior. In the case of single alkoxy chain at 4-position, there is a transition from Smectic C to Smectic A mesophase during cooling and Smectic A to Smectic C transition in heating cycle in all the homologues except n = 6 & n = 8. In the case of two alkoxy chains at 3-, 5-positions, the compounds are non-mesogenic in nature. On changing the position of alkoxy chains from 3-, 5-positions to 3-, 4-positions, intermolecular forces weaken and these compounds become liquid crystalline and show columnar rectangular mesophase resulting from the effect of regioisomerism. Moving on to the series with three alkoxy chains, it was observed that 2-, 3-, 4-trialkoxy substituted compounds exhibit columnar rectangular mesophase except lower chain length (n = 6 & 8) while 3-, 4-, 5-trialkoxy substituted aroylhydrazones show columnar rectangular mesophase; except n = 10 which shows columnar oblique mesophase. Thus it was established that on increasing density of alkoxy chains around one terminal, mesophase changes from smectic to columnar mesophase. Temperature dependent Raman studies confirm the presence of intermolecular hydrogen bonding. Further, effect of substitution pattern did not show much influence on the photophysical properties of the mesogenic series in solid and solution state. However, the non-mesogenic series showed a different absorption and emission transition from the mesogenic series in solid and solution state. Solid state fluorescence studies show almost similar emission maxima in all the series. However, it was also noticed that non-mesogenic series show maximum red shifted emission maxima in solid state as compared to that of solution. All the series showed good gelation properties with less than 1% CGC (wt%) suggesting the strong ability of molecules to form gel. These H-bonded liquid-crystalline gels have immense potential for applications in emissive displays. © 2019 Elsevier B.V.
Fabrication of liquid crystal based sensor for detection of hydrazine vapours
(Elsevier B.V., 2014) Nandi, Rajib; Singh, Sachin Kumar; Singh, Hemant Kumar; Singh, Bachcha; Singh, Ranjan K.
A novel liquid crystal (LC) based sensor to detect trace level amount of hydrazine vapour has been developed. The LC 4′-pentyl-4-biphenylcarbonitrile (5CB) doped with 0.5 wt% 4-decyloxy benzaldehyde (DBA) shows dark to bright optical texture upon exposure of hydrazine vapours as revealed by polarizing optical microscopy under crossed polarizers. The hydrazine interacts with the doped DBA and form diimine compound which disrupt the orientation of aligned 5CB. The interaction between DBA and hydrazine has been also studied by Raman spectroscopy. © 2014 Elsevier B.V. All rights reserved.
Fabrication of Liquid Crystal Optical Sensors Using Cyclodextrin Polymer for Real Time, Selective and Visible Detection of Industrial Dyes in Contaminated Natural Water Samples
(Wiley-VCH Verlag, 2025) Rashid, Madeeha; Pandey, Satyabratt; Singh, Vishal; Patel, Chandan Bhai; Singh, Ranjan Kumar; Singh, Sachin Kumar
Industrial wastewater release of dyes poses serious environmental and health risks when introduced into natural water systems. Herein, a cyclodextrin-based polymer sensor (Ech-CDP) is developed for real-time, visible detection of harmful methylene blue (MB) and methyl orange (MO) dyes in distilled and contaminated natural water samples. The sensor works through a competitive host-guest mechanism between sodium dodecyl sulphate (SDS) and Ech-CDP, altering liquid crystal alignment. Initially, SDS induces homeotropic ordering, which shifts to a tilted state upon binding with Ech-CDP. The presence of MB or MO displaces SDS, reverting the alignment and causing a visible bright-to-dark transition under polarizers. The sensor exhibits high selectivity, with detection limits of 0.03 mM for MB and 0.05 mM for MO in aqueous solutions, and 0.08 mM for MB and 0.26 mM for MO in real water samples, remains effective for 3 days, and is unaffected by pH variations between 4.8 and 9.1. Additionally, the sensor demonstrates an on–off switching capability, suggesting potential applications for molecular logic gates and advancing environmental monitoring techniques in dye-polluted waters. © 2025 Wiley-VCH GmbH.
In vitro anti-inflammatory and antioxidant activities of Hinguleswara rasa-based herbomineral formulations
(Innovare Academics Sciences Pvt. Ltd, 2018) Chatterjee, Abhishek; Baghel, Dileep Singh; Mittal, Amit; Singh, Saurabh; Kumar, Bimlesh; Pandey, Narendra Kumar; Singh, Sachin Kumar; Tamilvanan, S.; Chopra, Shruti; Bhatia, Amit; Chaudhary, Anand Kumar
Objective: The aims of the present investigation were to develop the herbal and/or herbomineral formulations of Hinguleswara rasa and to compare their anti-inflammatory and antioxidant activities, in vitro, with that of standard drug samples. Methods: This study was an interventional investigation in three samples: In the first sample, Hinguleswara rasa (HR1) was prepared as per methodology described in Rasatarangini using Shuddha Hingula (10 g), Shuddha Vatsanabha (10 g), and Pippali (10 g). In the second and third sample, respectively, Hinguleswara rasa was prepared by replacing Shuddha Hingula with Kajjali where Kajjali made from Hingulotha parada and Sodhita parada constitutes two varieties of Hinguleswara rasa, i.e. HR2 and HR3. In vitro antioxidant activity was studied using 2,2-diphenyl-1-picrylhydrazyl, and the absorbance was recorded at 517 nm. For evaluating the in vitro anti-inflammatory studies, the inhibition of albumin denaturation technique was performed. Results: The results showed that the formulation of Hinguleswara rasa has shown dose-dependent activity which was observed in 100 µg concentration. HR1, HR2, and HR3 showed 36.11, 17.22, and 16.11% radical scavenging activity. Conclusion: It could be concluded that the changes made in the formulations did not affect the in vitro anti-inflammatory and antioxidant effects of the herbomineral formulations. © 2018, Innovare Academics Sciences Pvt. Ltd. All rights reserved.
Investigation of coordination properties of isolated adenine to copper metal: A systematic spectroscopic and DFT study
(Elsevier B.V., 2013) Prakash, Om; Singh, Sachin Kumar; Singh, Bachcha; Singh, Ranjan K.
The coordination properties of copper with adenine have been studied by the analyzing the changes in Fourier Transform Infra-red (FTIR) and Raman spectra of adenine and adenine-copper complex. The geometry of adenine and adenine copper complex were optimized and theoretical Infra-red and Raman spectra of the optimized structures were calculated using Density Functional Theory (DFT). During synthesis of adenine-copper complex specific procedure was adopted to attach the Cu atom with particular N-atom of adenine (N9). The results of Raman and DFT confirmed the attachment. The Raman bands at 625, 330 and 230 cm-1 of adenine-copper complex contain significant contribution of the vibrational motions of Cu metal coordinated to N9 and Cl atoms. The DFT calculations give additional vibrational modes containing the Cu, N9 and N9/ atoms, which are not observed in FTIR and Raman spectra. The Raman, IR and DFT study confirm that Cu metal has good binding affinity to the isolated adenine base. © 2013 Elsevier B.V. All rights reserved.
Investigation of liquid crystalline property of a new calamitic liquid crystalline system methyl 4-(4ʹ-(4ʹʹ-(decyloxy)benzyloxy) benzylideneamino)benzoate
(Taylor and Francis Ltd., 2017) Nandi, Rajib; Singh, Hemant Kumar; Singh, Sachin Kumar; Rao, D. S. Shankar; Prasad, S. Krishna; Singh, Bachcha; Singh, Ranjan K.
A new polar calamitic liquid crystal, methyl 4-(4ʹ-(4ʺ-(decyloxy)benzyloxy) benzylideneamino)benzoate (M3BA) containing ether and Schiff base groups as linker with terminal polar ester group, has been synthesised and mesomorphic properties are studied by differential scanning calorimetry, polarising optical microscopy, density functional theory, temperature-dependent X-ray diffraction and temperature-dependent micro- Raman study. The smectic A (SmA) mesophase with focal conic texture has been observed with wide mesomorphic range. Layer thickness in SmA phase is greater than the optimised length of the molecule, indicating partially bilayer SmA phase. Analysis of Raman marker bands of C–H in-plane bending of phenyl rings, C=C stretching of rings, C=N stretching and C=O stretching shows structural changes at molecular level at Cr → SmA phase transition and provides proper intermolecular interactions responsible for dimeric unit in partially bilayer SmA phase. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
Liquid crystal based sensor system for the real time detection of mercuric ions in water using amphiphilic dithiocarbamate
(Elsevier B.V., 2016) Singh, Sachin Kumar; Nandi, Rajib; Mishra, Kirtika; Singh, Hemant Kumar; Singh, Ranjan Kumar; Singh, Bachcha
We developed a simple, sensitive, label-free and real time detection method for mercuric ions (Hg2+) in water using liquid crystals (LCs). In this system, newly synthesized amphiphilic potassium N-methyl-N-dodecyldithiocarbamate (MeDTC) was doped in 4-cyano-4′-pentyl biphenyl (5CB) LC, which align LC molecules at aqueous interface and polar head group of the amphiphile acts as mecuric ion specific chelating ligand. When this sensor system was incubated in the aqueous solution containing Hg2+ ions, a dark to bright transition of the image of LCs was observed. This was caused due to rapid and stable complex formation between dithiocarbamate chelating group of MeDTC with Hg2+ ions at aqueous interface, which disrupted the orientation of LCs giving bright texture. The limit of detection of the system for aqueous Hg2+ ion is 0.5 μM. This sensor did not respond to other metal ions like Pb2+, Cd2+, Cu2+, Zn2+, Na+, Mg2+ and Ca2+, which are common environmental interference in water. We also demonstrated that this sensor is capable of detecting Hg2+ ions in real water samples (tap water). The very simple and effective procedure reported here should facilitate the development of real time, portable and reliable LC based sensor for mercury pollution control. © 2015 Elsevier B.V. All rights reserved.
Liquid crystalline properties of 3-[4-(4′- alkoxybenzoyloxybenzylidene) amino]-1,2,4-triazines: Synthesis and characterization
(2010) Singh, Bachcha; Pandey, Ashwini; Singh, Sachin Kumar
A new series of 3-[4-(4′-alkoxybenzoyloxybenzylidene)amino]-1,2,4- triazines, C3H2N3N=CHC6H 4OCOC6H4OCmH2m+1 where m=6, 7, 8, 9, 10, 11, 12, 14, and 16 have been synthesized. These compounds have been characterized by elemental analyses, FT-IR, UV-visible, 1H, and 13C NMR spectroscopy. Mesomorphic properties of these compounds were studied by differential scanning calorimetry and polarizing microscopy. The mesomorphic nature of these compounds is dependent on the alkoxy chain length. The compounds (m=6, 7) do not exhibit mesomorphism while the compounds (m=8, 9, 11, 12, 14) show a monotropic nematic mesophase in cooling cycle. The 3-[4-(4′-decyloxybenzoyloxybenzylidene)amino]-1,2,4-triazine displays an enantiotropic nematic mesophase and the hexadecyloxy compound exhibits the smectic A mesophase. Copyright © Taylor & Francis Group, LLC.
Mesomorphic and DFT studies of terminal ester containing salicylaldimines and their copper (II) complexes
(Taylor and Francis Inc., 2017) Singh, Hemant Kumar; Singh, Sachin Kumar; Kumar, Vijay; Kanth, Priyanka; Mishra, Kirtika; Singh, Bachcha
In this article, we report synthesis and characterization of a novel homologous series of butyl 4-(4′-(alkoxy)-2-hydroxybenzylideneamino)benzoates, CnLH (n = 6, 8, 10, 12, 14, 16) and their copper(II) complexes. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and powder X-ray diffraction (XRD) studies. The ligands and their copper(II) complexes exhibit wide range of enantiotropic smectic A mesophase as confirmed by their typical optical texture under polarizing microscope. Thermal stability of the compounds is determined by thermo gravimetric analyses. DFT calculations have been performed using GAUSSIAN-09 program at B3LYP level to obtain the stable electronic structure of the ligand and its copper(II) complex. © 2017 Taylor & Francis Group, LLC.
Mesomorphic, micro-Raman and DFT studies of new calamitic liquid crystals; Methyl 4-[4-(4-alkoxy benzoyloxy)benzylideneamino]benzoates
(Elsevier, 2014) Nandi, Rajib; Singh, Hemant Kumar; Singh, Sachin Kumar; Singh, Bachcha; Singh, Ranjan K.
The mesomorphic properties of newly synthesized homologous series of calamitic liquid crystals; methyl 4-[4-(4-alkoxy benzoyloxy)benzylideneamino] benzoates, H2n+1CnOC 6H4COOC6H4C(H)N C6H 4COOCH3; n = 6, 8, 10, 12, 14, 16 (MABBAB-n) containing ester and Schiff base groups as linker have been studied by temperature dependent micro-Raman study, differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). All members of this series exhibit enantiotropic smectic A (SmA) mesophase with oily streak and focal conic textures. Analyses of Raman marker bands of phenyl rings, Schiff base and ester groups of MABBAB-10 confirm the phase transitions. The Raman study also gives an evidence of breaking of weak intermolecular hydrogen bonds associated with ester groups and formation of new hydrogen bonds through CN bond at Cr → SmA phase transition. The monomer and dimer were optimized and vibrational assignment of MABBAB-10 was also done with density functional theoretical (DFT) technique to understand the experimental results. © 2014 Elsevier Ltd. All rights reserved.
Metal Containing Liquid Crystalline Polymers
(Springer International Publishing, 2015) Singh, Bachcha; Singh, Sachin Kumar
Design and synthesis of multifunctional single molecules stabilizing liquid-crystalline phases are significant from both fundamental research and application point of views. This task seems to be fulfilled, in part, by metallomesogenic polymers or metal containing liquid crystal polymers (MLCPs) due to two promising elements- liquid crystallinity and metal centre in a single molecular unit with the processability of polymers. The variety of readily available metals incorporated into these mesogenic polymers introduces new physical properties and, consequently, new applications in the field of polymeric materials traditionally based on a few elements (C, H, N, O, halogens, S, P). In recent years enormous growth has occurred in the field of science and technology of metallomesogenic polymers as evident from a large number of publications on these materials. The present chapter will firstly describe general concept of metal containing liquid crystal polymers followed by classification of MLCPs in terms of their mesogenic behaviour (thermotropic and lyotropic) and chemical structures. A brief introduction of synthetic strategies i.e. molecular engineering of MLCPs will be presented in next section to draw a clear concept behind the designing of these functional materials. A special section will be devoted to recent advances including borderline cases in the field of metal containing liquid crystal polymers followed by concluding remarks and future perspective. © Springer International Publishing Switzerland 2016.
Microwave-assisted synthesis and mesomorphic investigations of p-substituted aroylhydrazones and their nickel(II) and copper(II) complexes
(Taylor and Francis Ltd., 2015) Singh, Sachin Kumar; Kumar, Vijay; Nandi, Rajib; Singh, Hemant Kumar; Singh, Ranjan K.; Singh, Bachcha
The present study is focused on the development of green microwave process for the synthesis of mesogenic substituted aroylhydrazones and their nickel(II) and copper(II) complexes. The compounds have been synthesised by microwave-assisted as well as thermal methods for comparison purpose. The compounds were structurally characterised by using suitable spectroscopic techniques. The mesomorphic properties were studied by differential scanning calorimetric analysis and polarising optical microscopy. The stable molecular structures of the mesogenic methylidenehydrazinato-nickel(II) complex have been obtained by density functional theoretical method to understand the structural origin responsible for the mesomorphic property. © 2015, Taylor & Francis.
Microwave-assisted synthesis, characterisation and mesomorphic investigations of novel disubstituted aroylhydrazones
(Taylor and Francis Ltd., 2015) Singh, Sachin Kumar; Kumar, Vijay; Singh, Hemant Kumar; Kanth, Priyanka; Singh, Bachcha
The present study is focused on the development of green microwave process for the synthesis of mesogenic substituted aroylhydrazones and their structure–mesophase relationship study. Two new liquid crystalline series of disubstituted aroylhydrazones with (ABB(OH)H-n) and without lateral hydroxyl group (ABBH-n) (n = 6–16) have been synthesised by microwave-assisted methods. The compounds were structurally characterised by using suitable spectroscopic techniques. The mesomorphic properties of the series of aroylhydrazones were examined using differential scanning calorimetric analysis and polarising optical microscopy. The relationship between structure and mesogenic properties was analysed by comparison of the present series and earlier reports on homostructural series of aroylhydrazones. Thus, the effects of substitution of phenyl rings with ester and ether linking group at both terminals and introduction of hydroxyl group at lateral position on stability of mesophase and their width were investigated. In general, all substituted aroylhydrazone derivatives exhibit SmC mesophase, and substitution of terminal and lateral group has considerably increased the stability and broadened the width of mesophase of the compounds. © 2015 Taylor & Francis.
Molecular approach to phase transitions in a calamitic ester substituted aroylhydrazone liquid crystal
(John Wiley and Sons Ltd, 2016) Nandi, Rajib; Singh, Sachin Kumar; Singh, Hemant Kumar; Shankar Rao, D.S.; Krishna Prasad, S.; Singh, Bachcha; Singh, Ranjan K.
Temperature dependent Raman and X-ray diffraction studies of a calamitic ester substituted aryolhydrazone liquid crystal (LC) system; N-[4-(4ʹ-decyloxy)benzoyloxy benzylidene]-Nʹ-[4ʹ-decyloxybenzoyl]hydrazine (DB2H) have been performed to investigate the molecular arrangement and intermolecular interaction environment in LC phase. X-ray diffraction study with the help of density functional theoretical study gives the information of molecular tilt angle in SmC layer. Prominent Raman signatures of crystal I → crystal II, crystal II → SmC and SmC → Isotropic phase transitions were identified in terms of changes in peak position and linewidth as well as Raman intensity. Analysis of Raman marker bands gives evidence of residual intermolecular hydrogen bonds between amide groups responsible for tilting arrangement in SmC phase. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Nuclear Magnetic Resonance Spectroscopy: Theory and Applications
(Springer, 2021) Rashid, Madeeha; Singh, Sachin Kumar; Singh, Chandan
Nuclear Magnetic Resonance (NMR) spectroscopy is considered as most powerful technique for structure elucidation of compounds. It is known as unambiguous technique for identification and structural-determination of organic compounds through its diverse variants. This chapter describes introduction to the basics of NMR technique-theory and technical interpretations, instrumentation, detailed descriptions of proton (1H) and carbon (13C)-NMR with suitable examples, brief introduction of other variants—DEPT, fluorine (19F), phosphorus (31P) of NMR techniques and recent applications of NMR-techniques in various fields. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Observation of exceptional 'de Vries-like' properties in a conventional aroylhydrazone based liquid crystal
(Royal Society of Chemistry, 2016) Singh, Hemant Kumar; Singh, Sachin Kumar; Nandi, Rajib; Rao, D. S. Shankar; Prasad, S. Krishna; Singh, Ranjan K.; Singh, Bachcha
Smectic liquid crystals with 'de Vries-like' properties are characterized by a maximum layer contraction of ≤1% upon transition from the non-tilted SmA phase to the tilted SmC phase. A straight alkoxy chain-terminated conventional aroylhydrazone based liquid crystal N-(4-(tetradecyloxy)-2-hydroxybenzylidene)-4′((4′′(hexadecyloxy)benzyl)oxy)benzohydrazide (BSac-1416) undergoes the SmA-SmC phase transition with a maximum layer contraction of 0.65%. The merits of the de Vries reduction factor, i.e. R and f values for this mesogen, are comparable to, or even lower than, those reported for established perfluorinated and polysiloxane-terminated bona fide de Vries-like materials. © 2016 The Royal Society of Chemistry.
Raman spectroscopic approach to monitor the in vitro cyclization of creatine → creatinine
(Elsevier, 2015) Gangopadhyay, Debraj; Sharma, Poornima; Singh, Sachin Kumar; Singh, Pushkar; Tarcea, Nicolae; Deckert, Volker; Popp, Jürgen; Singh, Ranjan K.
The creatine → creatinine cyclization, an important metabolic phenomenon has been initiated in vitro at acidic pH and studied through Raman spectroscopic and DFT approach. The equilibrium composition of neutral, zwitterionic and protonated microspecies of creatine has been monitored with time as the reaction proceeds. Time series Raman spectra show clear signature of creatinine formation at pH 3 after ∼240 min at room temperature and reaction is faster at higher temperature. The spectra at pH 1 and pH 5 do not show such signature up to 270 min implying faster reaction rate at pH 3. © 2014, Elsevier B.V. All rights reserved.

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