Papers by Hasi Rani Barai
Carbon Research, Oct 17, 2023
The surface properties of nanomaterials are an important consideration in most scientific and tec... more The surface properties of nanomaterials are an important consideration in most scientific and technological applications. Several methodologies can maneuver these properties while surface modification is the most common technique. Carbon Dots (CDs) are viable competitive materials for their pacific environment, chemical inertness, tunable photoluminescence, low cost, eco-friendliness, biocompatibility, schematic surface functionalization, and sophisticated utilization in nanomaterial's surface modification. The nanoparticle surface attribute is modified for a specific purpose to use in several applications by dint of the tunable properties of CDs. Multifunctional CDs have a great potential to replace traditionally toxic and costly quantum dots through surface modification. This review presents how multifunctional CDs conjugated with other nanoparticles take an active part in medicine and biomedical fields with chemical and physical collaborations. Moreover, the basics of conjugate formation by different chemical and physical interactions of functional molecules are appraised from multiple perspectives. This article also describes different modification mechanisms followed by properties of the modified nano-conjugates. The surface modification affects fluorescence quantum yields, complexation potential, fluorescent coloring, and quenching capabilities. Resultant-modified nanoconjugates are powerful surfaces for drug delivery, biosensing, bioimaging, analysis, and therapeutic methods. Finally, the most fruitful current challenges and further possibilities are discussed in the conclusion section. Highlights • Classified the modifications of carbon dots (CDs) surface. • Elaborated on the exceptional and recognized features of CDs. • Summarized the implementations of CDs for emerging applications. • Disclosed ongoing research, gaps, challenges, and potential scope of future work.
ACS omega, Aug 27, 2020
Cu-doped Mn 3 O 4 and Mn-doped CuO (CMO@MCO) mixed oxides with isolated phases together with pris... more Cu-doped Mn 3 O 4 and Mn-doped CuO (CMO@MCO) mixed oxides with isolated phases together with pristine Mn 3 O 4 (MO) and CuO (CO) have been synthesized by a simple solution process for applications in electrochemical supercapacitors. The crystallographic, spectroscopic, and morphological analyses revealed the formation of all of the materials with good crystallinity and purity with the creation of rhombohedral-shaped MO and CMO and a mixture of spherical and rod-shaped CO and MCO nanostructures. The ratio of CMO and MCO in the optimized CMO@MCO was 2:1 with the Cu and Mn dopants percentages of 12 and 15%, respectively. The MO-, CO-, and CMO@MCO-modified carbon cloth (CC) electrodes delivered the specific capacitance (C s) values of 541.1, 706.7, and 997.2 F/g at 5 mV/s and 413.4, 480.5, and 561.1 F/g at 1.3 A/g, respectively. This enhanced C s value of CMO@MCO with an energy density and a power density of 78.0 Wh/kg and 650.0 W/kg, respectively, could be attributed to the improvement of electrical conductivity induced by the dopants and the high percentage of oxygen vacancies. This corroborated to a decrease in the optical band gap and charge-transfer resistance (R ct) of CMO@MCO at the electrode/electrolyte interface compared to those of MO and CO. The net enhancement of the Faradaic contribution induced by the redox reaction of the dopant and improved surface area was also responsible for the better electrochemical performance of CMO@MCO. The CMO@MCO/CC electrode showed high electrochemical stability with a C s loss of only ca. 4.7%. This research could open up new possibilities for the development of doped mixed oxides for high-performance supercapacitors.
Materials Today Communications
Research Square (Research Square), Jul 21, 2023
The N-acetyl-phenylalaninylamide (NAPA) and microhydrated NAPA, [NAPA-A(H 2 O) n (n = 1, 2, 3, 4)... more The N-acetyl-phenylalaninylamide (NAPA) and microhydrated NAPA, [NAPA-A(H 2 O) n (n = 1, 2, 3, 4)] have been studied theoretically in the gas phase to explore the conformational landscape and the effect of hydration on the peptide backbone of NAPA. The most stable conformer of NAPA has an extended backbone form with the structural motif of β L (a) and assigned NAPA-A. After the addition of a single water molecule, the β L (a) structure of NAPA folded to γ-turn with a structural motif of γ L (a). The sequential addition of water on the NAPA-A conformer shows moderate intermolecular hydrogen bonding with the structural arrangement of PPII. Calculations for all the most stable conformers of NAPA-A(H 2 O) n (n = 1, 2, 3, 4) clusters have been done using B3LYP, B3PW91, PBE0, M06-2X, wB97XD, CAM-B3LYP density functionals with cc-pVTZ basis set in the gas phase to assess their ability to describe the conformational landscape and hydration effect. In terms of interaction energy and the strength of the hydrogen bond, the performance is obtained in the order of M06-2X > wB97XD > CAM-B3LYP > PBE0 > B3LYP > B3PW91 with cc-pVTZ basis set. We also calculated interaction energy using the MP2 method with 6-31G basis set to see the trends of interaction energy from the bare NAPA-A to [NAPA-A(H 2 O) n (n = 1, 2, 3, 4)] clusters. Moreover, natural bond orbital (NBO) analysis has been carried out to clarify the nature of hydrogen bonding in NAPA-A.
Bulletin of The Korean Chemical Society, Dec 20, 2011
The nucleophilic substitution reactions of ethylene phosphorochloridate (2) with X-pyridines are ... more The nucleophilic substitution reactions of ethylene phosphorochloridate (2) with X-pyridines are investigated kinetically in acetonitrile at-20.0 o C. The free energy correlations for substituent X variations in the nucleophiles exhibit biphasic concave upwards with a break point at X = 3-Ph. Unusual positive ρ X (= +2.49) and negative β X (=-0.41) values are obtained with the weakly basic pyridines, and rationalized by the isokinetic relationship with isokinetic temperature at t ISOKINETIC = 6.6 o C. The pyridinolysis rate of 2 with a cyclic five-membered ring is forty thousand times faster than its acyclic counterpart (3: diethyl chlorophosphate) because of great positive value of the entropy of activation of 2 (ΔS ≠ = +49.2 eu) compared to negative value of 3 (ΔS ≠ =-44.1 eu) over considerably unfavorable enthalpy of activation of 2 (ΔH ≠ = 28.4 kcal mol-1) compared to 3 (ΔH ≠ = 6.3 kcal mol-1). Great enthalpy and positive entropy of activation are ascribed to sterically congested transition state (TS) and solvent structure breaking in the TS. A concerted mechanism involving a change of nucleophilic attacking direction from a frontside attack with the strongly basic pyridines to a backside attack with the weakly basic pyridines is proposed.
Bulletin of The Korean Chemical Society, Feb 20, 2014
Nucleophilic substitution reactions of Y-aryl methyl (8) and Y-aryl propyl (10) chlorothiophospha... more Nucleophilic substitution reactions of Y-aryl methyl (8) and Y-aryl propyl (10) chlorothiophosphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at 55.0 o C. A concerted mechanism is proposed for 8 based on the negative ρ XY (=-0.23) value, while a stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed for 10 based on the positive ρ XY (= +0.68) value. The deuterium kinetic isotope effects (DKIEs; k H /k D) are 0.89-1.28 and 0.62-1.20 with 8 and 10, respectively. Primary normal and secondary inverse DKIEs are rationalized by a frontside attack involving hydrogen bonded, four-center-type transition state and backside attack involving in-line-type transition state, respectively.
Bulletin of The Korean Chemical Society, Mar 20, 2014
The nucleophilic substitution reactions of Y-aryl N,N-dimethyl phosphoroamidochloridates with sub... more The nucleophilic substitution reactions of Y-aryl N,N-dimethyl phosphoroamidochloridates with substituted anilines and deuterated anilines are kinetically investigated in acetonitrile at 65.0 o C. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed based on the positive ρ XY value. The deuterium kinetic isotope effects involving deuterated anilines show secondary inverse with all the nucleophiles, rationalized by a dominant backside nucleophilic attack.
Bulletin of The Korean Chemical Society, Sep 20, 2011
The nucleophilic substitution reactions of 1,2-phenylene phosphorochloridate (1) with substituted... more The nucleophilic substitution reactions of 1,2-phenylene phosphorochloridate (1) with substituted anilines (XC 6 H 4 NH 2) and deuterated anilines (XC 6 H 4 ND 2) are investigated kinetically in acetonitrile at-15.0 o C. The studied substrate of 1,2-phenylene phosphorochloridate is cyclic five-membered ring of phosphorus ester, and the anilinolysis rate of 1 is much faster than its acyclic analogue (4: ethyl phenyl chlorophosphate) because of extremely small magnitude of the entropy of activation of 1 compared to 4. The Hammett and Brönsted plots exhibit biphasic concave upwards for substituent X variations in the nucleophiles with a break point at X = 3-Me. The values of deuterium kinetic isotope effects (DKIEs; k H /k D) change from secondary inverse (k H /k D < 1) with the strongly basic anilines to primary normal (k H /k D > 1) with the weakly basic anilines. The secondary inverse with the strongly basic anilines and primary normal DKIEs with the weakly basic anilines are rationalized by the transition state (TS) variation from a predominant backside attack to a predominant frontside attack, in which the reaction mechanism is a concerted S N 2 pathway. The primary normal DKIEs are substantiated by a hydrogen bonded, four-center-type TS.
Bulletin of The Korean Chemical Society, Sep 20, 2014
Nucleophilic substitution reactions of Y-aryl methyl (8) and Y-aryl propyl (10) chlorothiophospha... more Nucleophilic substitution reactions of Y-aryl methyl (8) and Y-aryl propyl (10) chlorothiophosphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at 55.0 o C. A concerted mechanism is proposed for 8 based on the negative ρ XY (=-0.23) value, while a stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed for 10 based on the positive ρ XY (= +0.68) value. The deuterium kinetic isotope effects (DKIEs; k H /k D) are 0.89-1.28 and 0.62-1.20 with 8 and 10, respectively. Primary normal and secondary inverse DKIEs are rationalized by a frontside attack involving hydrogen bonded, four-center-type transition state and backside attack involving in-line-type transition state, respectively.
Bulletin of The Korean Chemical Society, Jul 20, 2011
Kinetic studies for the reactions of O,O-dimethyl Z-S-aryl phosphorothioates with X-pyridines hav... more Kinetic studies for the reactions of O,O-dimethyl Z-S-aryl phosphorothioates with X-pyridines have been carried out in dimethyl sulfoxide at 85.0 ºC. The Hammett and Brönsted plots for substituent X variations in the nucleophiles are biphasic concave upwards with a break point at X = H, while those for substituent Z variations in the leaving groups are linear. The negative sign of the cross-interaction constant (ρ XZ) implies that the reaction proceeds through a concerted mechanism for both the strongly and weakly basic pyridines. The magnitude of ρ XZ (=-0.35) for the strongly basic pyridines is greater than that (ρ XZ =-0.15) for the weakly basic pyridines, indicating a change of the nucleophilic attacking direction from frontside for the strongly basic pyridines to backside for the weakly basic pyridines. The early transition state is proposed on the basis of the absence of positive deviations from both the Hammett and Brönsted plots for the strong π-acceptor, X = 4-Ac, and small values of ρ XZ and β X .
Chemical Engineering Science
This paper reports the influence of the solvent&#39;s properties on the growth mechanism of z... more This paper reports the influence of the solvent&#39;s properties on the growth mechanism of zinc cobaltite (ZnCo 2 O 4) microstructures and their surface morphologies. We observed that the ZnCo 2 O 4 microstructures (ZCO) offer a large number of interacting sites due to the solvent variation, influencing the phase purity and high crystallinity of the ZnCo 2 O 4, which strongly affects its electrochemical conductivity. ZCO crystals were synthesized separately in water, ethanol, and isopropyl alcohol solvent at 180 • C for 12 h, governing the formation of 2D sheet-like morphology in water (ZCO-DIW), 3D flower-like and peanut-like morphologies in ethanol (ZCO-ETH), and isopropyl alcohol (ZCO-IPA), respectively. The successful formation of ZCO morphologies was confirmed through high-resolution scanning electron microscopy. Concerning the solvent variation, the specific surface area of the three ZCO electrodes varies in ascending order as ZCO-DIW (23.78 m 2 g − 1) &lt; ZCO-IPA (27.19 m 2 g − 1) &lt; ZCO-ETH (37.19 m 2 g − 1). We also proposed a model for this solvent-dependent formation mechanism of three ZCO electrodes via the self-assembly process. The electrochemical performance of the ZCO electrodes exhibits excellent battery-type behavior with a specific capacity of 98.89 mAh g − 1 (for ZCO-ETH) owing to the highly porous flower-like morphology. These results revealed a simple and cost-effective synthesis strategy to fabricate micro/nano-structure with diverse morphology for a wide range of interfacial applications.
ACS Omega
For several years, ceramic biomaterials have been extensively utilized to rebuild and substitute ... more For several years, ceramic biomaterials have been extensively utilized to rebuild and substitute for body tissues. Calcium silicates have been proven to exhibit excellent bioactivity due to apatite formation and cell proliferation stimulation, in addition to degradability at levels adequate for hard tissue formation. These ceramics' excellent biological characteristics have attracted researchers. Baghdadite is a calcium silicate incorporating zirconium ions that enhances human osteoblast multiplication and development, increasing mineralization, and ossification. It has currently received much interest in academic institutions and has been extensively explored in the form of permeable frameworks, varnishes, bone adhesive and gap fillings, microparticles, and nanospheres, particularly in a wide range of biomedical applications. This review article aims to summarize and analyze the most recent research on baghdadite's mechanical characteristics, apatite-forming capability, dissolution pattern, and physiochemical qualities as a scaffold for dentofacial tissuèregeneration purposes.
Pharmaceuticals
Regenerative medicine, and dentistry offers enormous potential for enhancing treatment results an... more Regenerative medicine, and dentistry offers enormous potential for enhancing treatment results and has been fueled by bioengineering breakthroughs over the previous few decades. Bioengineered tissues and constructing functional structures capable of healing, maintaining, and regenerating damaged tissues and organs have had a broad influence on medicine and dentistry. Approaches for combining bioinspired materials, cells, and therapeutic chemicals are critical in stimulating tissue regeneration or as medicinal systems. Because of its capacity to maintain an unique 3D form, offer physical stability for the cells in produced tissues, and replicate the native tissues, hydrogels have been utilized as one of the most frequent tissue engineering scaffolds during the last twenty years. Hydrogels’ high water content can provide an excellent conditions for cell viability as well as an architecture that mimics real tissues, bone, and cartilage. Hydrogels have been used to enable cell immobiliz...
Pharmaceutics
In recent years, polymer-supported magnetic iron oxide nanoparticles (MIO-NPs) have gained a lot ... more In recent years, polymer-supported magnetic iron oxide nanoparticles (MIO-NPs) have gained a lot of attention in biomedical and healthcare applications due to their unique magnetic properties, low toxicity, cost-effectiveness, biocompatibility, and biodegradability. In this study, waste tissue papers (WTP) and sugarcane bagasse (SCB) were utilized to prepare magnetic iron oxide (MIO)-incorporated WTP/MIO and SCB/MIO nanocomposite particles (NCPs) based on in situ co-precipitation methods, and they were characterized using advanced spectroscopic techniques. In addition, their anti-oxidant and drug-delivery properties were investigated. Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analyses revealed that the shapes of the MIO-NPs, SCB/MIO-NCPs, and WTP/MIO-NCPs were agglomerated and irregularly spherical with a crystallite size of 12.38 nm, 10.85 nm, and 11.47 nm, respectively. Vibrational sample magnetometry (VSM) analysis showed that both the NPs an...
Micromachines
In this study, magnetite nanoparticles (Fe3O4 NPs) were synthesized using Baccaurea ramiflora lea... more In this study, magnetite nanoparticles (Fe3O4 NPs) were synthesized using Baccaurea ramiflora leaf extracts and characterized by visual observation, UV–Vis, FTIR, XRD, FESEM, and EDS. The UV−Vis spectrum showed continuous absorption at 300–500 nm, confirming the formation of Fe3O4 NPs. FTIR revealed that compounds containing the O-H group act as reducing agents during Fe3O4 NPs formation. Agglomerated spherical NPs were observed in the FESEM image. The prominent peak at ~6.4 keV in the EDS spectrum ascertained the existence of Fe, while the sharp peak at ~0.53 keV confirmed the presence of elemental oxygen. XRD patterns affirmed the crystalline nature. The size of as-synthesized NPs was observed to be 8.83 nm. The catalytic activity of Fe3O4 NPs for the reduction of methylene blue (MB) dye was monitored by UV–Vis. The maximum absorption peak of MB dye at 664 nm was almost diminished within 20 min, which revealed Fe3O4 NPs could be an excellent catalyst for wastewater treatment.
Polymers
Temperature-induced, rapid changes in the viscosity and reproducible 3-D structure formation make... more Temperature-induced, rapid changes in the viscosity and reproducible 3-D structure formation makes thermos-sensitive hydrogels an ideal delivery system to act as a cell scaffold or a drug reservoir. Moreover, the hydrogels’ minimum invasiveness, high biocompatibility, and facile elimination from the body have gathered a lot of attention from researchers. This review article attempts to present a complete picture of the exhaustive arena, including the synthesis, mechanism, and biomedical applications of thermosensitive hydrogels. A special section on intellectual property and marketed products tries to shed some light on the commercial potential of thermosensitive hydrogels.
Polymers
Bone and periodontium are tissues that have a unique capacity to repair from harm. However, repla... more Bone and periodontium are tissues that have a unique capacity to repair from harm. However, replacing or regrowing missing tissues is not always effective, and it becomes more difficult as the defect grows larger. Because of aging and the increased prevalence of debilitating disorders such as diabetes, there is a considerable increase in demand for orthopedic and periodontal surgical operations, and successful techniques for tissue regeneration are still required. Even with significant limitations, such as quantity and the need for a donor area, autogenous bone grafts remain the best solution. Topical administration methods integrate osteoconductive biomaterial and osteoinductive chemicals as hormones as alternative options. This is a promising method for removing the need for autogenous bone transplantation. Furthermore, despite enormous investigation, there is currently no single approach that can reproduce all the physiologic activities of autogenous bone transplants. The localiz...
Uploads
Papers by Hasi Rani Barai