Itaconic acid and its applications for textile, pharma and agro-industrial purposes

Itaconic acid (IA) is a well-known bio-based monounsaturated organic acid (C5H6O4), with a white color and crystalline structure. It is widely used in the agro-based, plastics, textile, paint and pharmaceutical sectors, owing to its flexible structure, due to the presence of functional groups with covalent double bonds. IA is an alternative to the petrochemicals acrylic and methacrylic acids. Commercial manufacturing of IA using Aspergillus terreus is more economically effective and feasible, and the Department of Energy (DOE) of the United States added IA under the “top 12” organic chemicals in 2004. This review provides an overview on the synthesis of IA and improvement of its yield by mutagenesis and metabolic engineering of Aspergillus and other fungal strains, along with its wide applications for food, pharmaceutical and textile purposes

Exploration of New Eu(III) Complexes and their Applications in Light Emitting Diodes and Sensors: Combined Experimental and Theoretical Investigations

This thesis work mainly going to describe about the designing and synthesis of the ancillary ligand (antenna) for the Eu(III) based complexes and to investigate their application in red/white LEDs, sensors (temperature and vapoluminescence sensor) Chapter 1, represents a general introduction of lanthanides and its unique spectral properties and it application in various fields. The importance of Eu(III) complexes, antenna effect (DBM and ancillary ligand), the lanthanides (specially Eu(III)) application in Red/white LED, temperature sensor and vapoluminescence were systematically discussed. In addition, the recent progress of Eu(III) complexes for LEDs and sensors were also been discussed. The main objective and significance of the present work of the thesis were documented. Chapter 2, Narrow band red emitting phosphor plays vital role in high performance smart white LEDs. In this context, a series of new Eu(III) complexes have been synthesized with neutral ligand (C1functionalised Phenanthro-imidazole-based ancillary ligands substituted with functionalized phenyl moieties and DBM as an anionic ligand. All the newly synthesized Eu-complexes showed extremely narrow band red emission due to ED transition (5D0-7F2, both in solid and thin film) with high quantum efficiency. Combined experimental and theoretical study indicates that the energy transfer from ligand to metal ion is complete. Temperature dependent PL study in solution reveals that the red emission is retained (only the ED (5D0-7F2) intensity decreases with increasing temperature). Red LED and hybrid white LEDs were fabricated by using near UV LED chip with Eu-complexes and near UV/blue LED conjugated with yellow dye and Eu-complex mixture, respectively. Hybrid white LED (Eu(DBM)3PhenpCN-pCF3 + yellow dye) showed superior CRI (84%), CIE (x = 0.36, y = 0.39) (near UV based) and CRI (82%), CIE (x = 0.34, y = 0.36) (blue LED based). In addition, presently studied Eu-complexes showed excellent reversible on-off-on luminescence behavior with exposure of acid-base vapours. Detailed spectroscopic investigation reveals that the protonation of the Eu-complexes (ligands) plays key role in the on-off-on luminescence. Chapter 3, a series of luminescent ternary Eu(III) complexes were synthesized and studied their photophysical properties. PL emission spectra of ligands showed blue emission, whereas Eu(III) complex showed red emission in solid while in solution phase Eu(DBM)3Phen-pCH3-mCF3 are showing multiple emission (near white emission). Fabrication of LED has been done by conjugating the Eu-complex with near UV LED the obtained results are very close to National Television System Committee (NTSC) standard for pure red emission. LED fabrication of Eu(DBM)3Phen-pCH3-mCF3 with 1:50 ratio show near white emission with CIE, x = 0.35, y = 0.20. In addition, presently studied Eu(III) complex shows excellent sensing behavior in the thermo-sensor (in the range 303K-453K) and vapoluminescent sensor. Chapter 4, Eu(III) complexes coordinated with phenanthroimidazole ligands based on fluorinated moieties (ancillary ligand) and DBM (anionic ligand) were designed and synthesized successfully. Eucomplexes in solid phase shown pure red emission (due to ED transitions) and solution slightly deviated (observed multiple emission) due to ligand emission in the EuIII complex. Solvatochromism study reveals that the Eu-complexes showed red emission along with the ligand emission peak (comparatively intense) in methanol and DMSO solution, which leads to obtain white emission. In addition, the lifetime of the fluorinated mCF3 ligand revealed high. Remarkable linear decrease in luminescence intensity with increasing the temperature, open up the new window to use this material as sensitive temperature sensor in the temperature range of 30−80oC. Fabricated red LEDs (InGaN) showed very close to the NTSC standard values for bright red emission. EuIII complexes exhibits on−off switching of photoluminescence via vapoluminescence process and observed best response to the acid-base (HCl-NH3) vapours. Chapter 5, a series of soft UV excitable new narrow-band red-emitting trivalent europium complexes were designed, synthesized and their photophysical properties were studied. The newly synthesized ancillary ligands showed deep blue emission with CIE y < 0.1. In contrast, the corresponding Eu(III) complexes shown extremely narrow-band red emission (in solid, solution [except pCF3 functionalized Eu(III) complex, it shown both ligand and Eu emission leads to nearly white emission] and thin-film) with wide excitation range (200-500 nm, where the near UV and blue LED emission occurs). Solvatochromism study reveals that the Eu-complexes showed multi-color emission. The hybrid white LED was fabricated by conjugating the near UV LED with yellow organic dye and 5-Eu complex, the results showed extremely high CRI (96%), CCT (4447 K) and the CIE color coordinate (x = 0.36, y = 0.35). In addition, the complexes were used for acid-base sensing. All the complexes showed very good reversible on-off-on luminescence behavior (exposure of complexes with HCl and NH3) and these complexes can find potential applications in anti-counterfeiting. Chapter 6, a series of smart luminescent Eu(III) complexes were synthesized by using C1-functionalize phenanthro-imidazole derivatives as a neutral ligand and DBM (anionic ligand). PL emission spectra of ligands showed blue to bluish-green emission, whereas their corresponding Eu-complexes shown multicolor emission in solution and red emission in solid state (solid as well as neat thin film).Energy transfer mechanism between ligand to Eu(III) ion is explained based on both theoretical (DFT and TD-DFT) and experimental study. The red LEDs were fabricated and found all the LEDs shown excellent color purity. Hybrid white LED was fabricated by conjugating the mixed phosphor dye (ligand and complex) with near UV LED shown superior white light emission (CCT (5298), CRI (80%), CIE (x = 0.337, y = 0.343)). In addition, dual emission Eu(III) complexes were explored for thermos-sensor (in the range 303 K – 353 K) applications. Paper based acid-base vapour sensor (exposure leads to switch in the emission color (bluishgreen to red)) of these complexes were explored and can also be used for anti-counterfeiting applications. Chapter 7, Promoting from the structural flexibility and easy solution process capability, single component white light emitting pure organo-lanthanide complexes have considered as a promising candidate for solid state lighting. A series of ancillary ligand by using imidazo-bipyridyl derivatives and DBM, as anionic ligand are employed to synthesized ternary Eu(III) complex.The photophysical and electrochemical properties of the ligand and their Eu(III) complexes were carefully investigated and the energy transfer mechanism were understood by combined experimental and theoretical calculation. Multiple-emission from both ligand and Eu(III)-ion leads to single component white light emission. White light emitting diodes (LED)was fabricated by conjugating the Eu-complex with near UVLED, the results showed superior performance (CIE (x = 0.33, y = 0.33, close to NTSC standard for pure white emission), correlated color temperature CCT (5386 K) and color rendering index CRI (63%)).The selected Eu-complex was further coated on blue LED chip and the corresponding white LED showed CIE (x = 0.36, y = 0.35), CCT (4234K) and CRI (75%). In addition, taking benefit of dual characteristic emission of the Eu-complexes, the ratiometric sensing behavior was explored. The Eu(DBM)3L-mCF3 have the relative sensitivity value of 4.9% K-1 at 323 K. Chapter 8, spectral window of dual visible light emissions of molecular europium complex leads to white light can be modulated by design strategy. A Eu-complex with butterfly structure displays dual emission, leads to single phase white light emitting molecular complex with excellent colour quality. Such behaviour is not observed with an analogous Eu-complex with triangle structure (rather shows usual red emission), suggesting that the partial lighting up of Eu-ion along with ligand emission (controlled energy transfer from ligand to EuIII ion) is more imperative for the creation of white light. The white LED assembled using butterfly Eu phosphor as white emitter yields a bright pure white light with CRI (95%), CCT (5457 K) and CIE (x = 0.33, y = 0.33),whereas the triangle Eu-phosphor displays red light with CIE value of x = 0.58, y = 0.31. The fabricated white/red LED continued to emit a bright white/red light even more than a year. The present design strategy can be widely adapted to synthesis single phase white emitting Eu-phosphor as well as explored for temperature sensing and sensor for vapoluminescence. Chapter 9, deals the summary and conclusion as well as future perspective of the work. The present thesis works deals with rational design and synthesis of new and novel class of ancillary ligand and their corresponding Eu3+ complexes for white LEDs and sensor (temperature and vapoluminescence). In addition, Eu molecular complexes also been explored for single component white light emitter based white LEDs. The observations and the conclusions derived from the present investigations are summarized in this chapter

Spatially dispersed one-dimensional carbon architecture on oxide framework for oxygen electrochemistry

The rational design of bifunctional electrocatalyst is important for sustainable energy storage and conversion devices such as metal-air batteries and fuel cells. Herein, we have designed a unique architecture where carbon nanotubes (CNTs) are supported on an oxide template. NiCo encapsulated N-doped carbon nanotubes were grown vertically outward from the nickel–cobalt oxide flowers for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The hybrid shows enhanced water oxidation performance (321 mV at 10 mA/cm2) and decent ORR activity (E1/2 at 0.75 V vs RHE) due to better conductivity and a large electrochemical surface area. Enhanced OER activity can be ascribed to high Ni and Ni3+ content whereas improved ORR activity results from enhanced active nitrogen species (pyridinic, M−Nx and graphitic) and higher water contact angle (due to unique architecture). Further, reversible oxygen electrochemistry with Δ E = 0.80 V indicates its potential as a bifunctional electrocatalyst. The hybrid electrocatalyst has shown good operational stability and durability for OER and ORR. Finally, the practical feasibility as cathode catalyst for metal-air battery has been demonstrated by powering a light emitting diode.Ministry of Education (MOE)Submitted/Accepted versionThe authors gratefully acknowledge DST-FIST (SR/FST/PSII-009/2010), India and Ministry of Education, Singapore (RG15/16, RG16/18) for the financial support

Clinicodemographic profile and treatment outcome in patients of ocular surface squamous neoplasia

Purpose: The aim is to study the clinicodemographic profile and treatment outcome of ocular surface squamous neoplasia (OSSN). Methods: This was a retrospective observational study of 57 eyes (56 cases) with clinically diagnosed OSSN, presenting in our center over the past year. Results: The median age of presentation was 55 years with male:female ratio being 4.5:1. Systemic predisposing conditions were xeroderma pigmentosa (1) postkidney transplant immunosuppression (1), and human immunodeficiency virus infection (1). Patients with predisposing conditions had a younger median age of onset (33 years). The majority of tumors were nodular (61.4%), gelatinous (61.4%), and had limbal involvement (96%). On ultrasound biomicroscopy (UBM), mean tumor height was 2.93 ± 1.02 mm, and intraocular extension was evident in seven eyes. OSSN with intraocular extension had a mean tumor height of 4.3 ± 1.32 mm. Nodal metastasis was seen in one case at presentation. As per American Joint Committee for Cancer Classification seventh edition staging-two cases were T1, one was T2, 46 were T3 and eight were T4. Treatment advised included conservative therapy for 39; wide local excision (4 mm margin clearance) with cryotherapy for seven; enucleation in four; and exenteration in four eyes. Overall, complete regression was achieved in 88% of cases during a mean follow-up of 13.5 ± 4.6 months. Recurrence was seen in three cases, which were treated with exenteration, radical neck dissection, and palliative chemo-radiotherapy, respectively. Conclusion: Although associated with old age, earlier onset of OSSN is seen in patients with systemic predisposing conditions. Thicker tumors in the setting of a previous surgery or immunocompromised status should be considered high-risk features for intraocular extension and should be evaluated on UBM

Insights into improving photoelectrochemical water-splitting performance using hematite anode

Designing an efficient photoanode is of great importance for photoassisted solar water splitting. Herein, a series of modifications to a nanorod structure hematite, to be used as anode for photoelectrochemical (PEC) water-splitting reactions is designed. Ti doping, oxygen vacancy formation by N2 treatment, TiO2 passivation, and FeOOH cocatalyst decoration are explored for their roles and contributions to the improvement of the PEC water oxidation performance. It is found that Ti doping and N2 treatment can greatly increase the charge carrier density, which has boosted the photocurrent. TiO2 passivation enhances the photovoltage, resulting in a cathodic shift in the onset potential (≈170 mV with respect to prepassivation). Further, the FeOOH cocatalyst decoration improves the reaction kinetics, thereby improving the overall photoassisted water oxidation performance.Ministry of Education (MOE)Submitted/Accepted versionThe authors gratefully acknowledge DST-FIST, India (SR/FST/PSII-009/2010), and Ministry of Education, Singapore (RG15/16, RG16/18), for financial support

Trimetallic oxide-hydroxide porous nanosheets for efficient water oxidation

Multimetallic systems have been the subject of intensive research for their promising electrocatalytic activities. Herein, we describe the synthesis of bimetallic and trimetallic (Ni, Co and Mn) oxide-hydroxide nanosheets and evaluate their catalytic activity toward water oxidation. The catalytic activity of porous trimetallic nanosheets was found to be higher than that of bimetallic hybrids. In addition, the trimetallic systems also possess excellent stability. A current density of 10 mA/cm2 is achieved for an overpotential of 287 mV and ∼0% loss even after 8000 cycles. The enhanced performance by the trimetallic system can be attributed to the large electrochemical surface area and better intrinsic activity. The electronic modulation in this three-element system is evident from the X-Ray Photoelectron Spectroscopy (XPS) study and Mott-Schottky analysis. The position of flat-band potential plays a significant role in determining the charge transfer kinetics, thereby affecting the water oxidation activity in the semiconductor-electrolyte system. Trimetallic system also offers better oxygen evolution reaction kinetics as evident from the least activation energy compared to the bimetallic counterparts. The local structure system is realized with the X-ray absorption spectroscopy (XAS) analysis. The present study highlights the importance of intrinsic activity in designing efficient non-noble metal electrocatalysts.Ministry of Education (MOE)Submitted/Accepted versionThe authors gratefully acknowledge DST-FIST (SR/FST/PSII-009/2010), India and Ministry of Education, Singapore (RG15/16, RG16/18) for the financial support