Photocatalytic Application of Bismuth Based Semiconducting Nanoparticles and their Heterostructures towards Selective Organic Transformations and Degradation of Persistent Organic Pollutants

In this thesis, Bi based complex oxides and sulphide semiconductor nanomaterials have been synthesized by combustion synthesis route. The Bi based materials have been coupled with low band gap metal sulphide materials to form heterojunction photocatalytic systems with improved visible light absorption and photon harvesting efficiency. The photocatalytic activity of the heterostructure systems have been studied for degradation of organic pollutants from aqueous sources and selective organic transformation reactions under visible light illumination. Bismuth tungstate (Bi2WO6) nanoparticles were synthesized by combustion synthesis method using different N-containing organic compounds as fuels (urea, glycine, hexamethylenetetramine (HMTA), malonic acid dihydrazide (MDH)). Glycine as fuel was effective for synthesis of phase pure Bi2WO6 nanoparticles. Employing HMTA and MDH as fuel lead to mixed phase complex oxide system with Bi14W2O27 as minor (impurity) phase. The nature of the fuel significantly influences the particle size and morphology. The Bi2WO6 nanoparticles were used as an efficient photocatalyst for the visible light driven chemoselective oxidation of substituted thiophenols to disulfide using air as oxidant. Structurally diverse diphenyl disulfide moieties were obtained in high yield and excellent selectivity within a time span of 6 h of visible light irradiation. The Bi2WO6 nanoparticles were also synthesized by amorphous citrate process and subsequently modified by dispersing CuS to form CuS/Bi2WO6 (CuSBTA) heterojunction materials. XRD study indicated the existence of hexagonal covellite CuS and orthorhombic Russellite Bi2WO6 phase in the heterojunction materials. During hydrothermal treatment, the Cu2+ ions substituted for the W6+ ions in the Bi2WO6 lattice to form a substitutional solid solution (Bi2CuxW1-xO6-2x). The CuS and Bi2WO6 phases existed in distinct nanorod and nanosheet morphologies, respectively. During hydrothermal treatment, significant morphological reorganization of the Bi2WO6 phase took place leading to the formation of flower like hierarchical nanostructures. The CuSBTA materials possess characteristic features of a type-II heterojunction exhibiting narrow band gap, enhanced visible light absorption and efficient charge separation properties. The heterojunction materials were evaluated as visible light active photocatalyst for complete degradation of Congo red dye using H2O2 as oxidant. The CuSBTA materials exhibited higher apparent rate constant (Kapp) and greater efficiency for Congo red degradation compared to pure Bi2WO6 material. A series of type-II heterojunction nanomaterials were synthesized by coupling Bi2W2O9 with CdS and CuS. Initially, phase pure Bi2W2O9 with orthorhombic crystalline structure was prepared by a facile combustion synthesis route using urea as a fuel. The CuS and CdS nanoparticles were dispersed over Bi2W2O9 matrix by using a hydrothermal route. The heterojunction materials were characterized using XRD, XPS, FTIR, UV-Vis-DRS, PL, FESEM and HRTEM study. Pure Bi2W2O9 exhibited micron-size plate-like particles. The occurrence of ultrafine CdS nanoparticles with diameter between 8-15 nm well dispersed over Bi2W2O9 plates is noticed for CdS/Bi2W2O9 materials. For CuS/ Bi2W2O9 materials, Cu2+ ions replaced partially W6+ ions in Bi2W2O9 lattice to form Bi2CuxW2-xO9-2x as a nonstoichiometric solid solution phase. Under hydrothermal treatment, the desegregation of the Bi2W2O9 plates to nanosheets and the concurrent formation of CuS nanorods were noticed leading to their hierarchical reorganisation to microspherical structures. Both the heterojunction materials, exhibited improved visible light absorption, enhanced charge carrier separation and suitable band alignment characteristic of a type-II heterojunction. The CdS/Bi2W2O9 heterojunctions were evaluated as visible light active photocatalyst for aerobic oxidation of amines to imines. Structurally and functionally diverse amine molecules were oxidized to the corresponding imines with excellent selectivity in a short span of time. The CuS/Bi2W2O9 heterojunction materials were studied as an efficient photocatalyst for the degradation of diuron pesticide under visible light irradiation achieving 95% mineralization within 3 h. Mechanistic study indicated that the mineralization of diuron occurred in a cascade manner over the catalyst surface involving dechlorination, alkyl oxidation and oxidative ring-opening steps. A visible light promoted photocatalytic route has been developed for mineralization of alachlor pesticide using type-II CuS/BiFeO3 heterojunction materials. The heterojunctions were synthesized by a two-step process involving synthesis of BiFeO3 by combustion route followed by deposition of CuS material by hydrothermal route. Microscopically, the heterojunction materials contained BiFeO3 nanoplates and CuS nanorods. Optical property study and photocurrent measurement suggested that these materials show excellent absorption in visible region with superior charge carrier mobility and separation compared to the individual components. The CuS/BiFeO3 materials showed high efficiency for mineralization of alachlor pesticide under visible light illumination achieving >95% degradation within 60 min. The mechanism of alachlor degradation over the catalyst surface was elucidated using GCMS and radical scavenger experiments. A series of α-Fe2O3-Bi2S3 heterojunction materials were prepared by a one-step autocombustion method employing thiourea as fuel and characterized using XRD, UV–Vis-DRS, FTIR, PL, XPS, FESEM, TEM and HRTEM analytical techniques. XRD study indicated presence of rhombohedral α-Fe2O3 and orthorhombic Bi2S3 in the heterojunction materials. The heterojunctions displayed better optical absorption in the visible region. Microscopic studies indicated presence of well dispersed α-Fe2O3 nanorods in a continuous Bi2S3 matrix. The α-Fe2O3 nanorods were typically 30–50 nm in diameter and 120–150 nm in length growing isotopically in different direction from a single nucleation point. The calculated band positions of both components indicated a facile electrons transfer from the conduction band of α-Fe2O3 to Bi2S3 whereas migration of holes occurs in the reverse direction yielding a type-II heterojunction. The α-Fe2O3 -Bi2S3 heterojunctions materials were evaluated as selective and efficient photocatalyst for the hydrogen transfer reduction of nitroarenes under visible light illumination. Structurally diverse nitroarenes could be selectively reduced to the corresponding amines in high yield and purity using α-Fe2O3 -Bi2S3 as photocatalyst

Pain Management in the Emergency Department- Newer Modalities and Current Perspective

Pain is one of the most common complaints and yet one of the most neglected aspects of management in the emergency department. Optimal pain management is a nuanced skill which focusses on reduction of pain to an acceptable level to allow for safe discharge and return to normal activities, in addition to improving patient satisfaction and comfort during their stay in hospital. Adequate analgesia also improves physiological parameters such as heart rate and blood pressure. The aim is improving rather than eradication of pain altogether while maintaining an acceptable level of adverse effects. This chapter will discuss assessment of pain in the emergency department along with various modalities of pain management with specific focus on newer modalities including ultrasound guided regional nerve blocks. Ultrasound guided nerve blocks are associated with better analgesia and have fewer chances of drug related adverse events, especially in older patients and those with comorbidities where large doses of systemic medications are associated with a significant risk of adverse effects

Practice Changing Innovations for Emergency Care during the COVID-19 Pandemic in Resource Limited Settings

COVID-19 has affected millions worldwide. To combat the infectious pandemic in resource limited settings, healthcare workers and techies have come up with multiple innovations. Nations with scarcity of resources have resorted to innovative strategies involving optimal utilization and repurposing of available commodities to overcome the demand–supply mismatch. Emergency rooms overburdened with diseased population are resorting to local innovative ideas to overcome obstacles in COVID-19 patient care. Point of care testing strategies in emergency rooms, sampling booths to reduce Personal Protective Equipment (PPE) use, disinfection strategies such as tunnel disinfection and local production of sanitizers, face masks/shields, aerosol containment chambers, novel triage protocols, telehealth care strategies reaching out to remote population and utilizing point for care ultrasound for resuscitation are few of the novel innovations which have benefitted medical fraternity and patient care in testing times. Medical innovations have emerged as the positive outcome of otherwise devastating COVID-19 pandemic. These practice changing innovations could also prove beneficial in future infectious pandemics

Survival of malarial acute kidney injury in children: A prospective analytical study

Introduction: The renal involvement has been reported in Plasmodium falciparum, Plasmodium malariae, and recently in Plasmodium vivax infection. Although malaria is highly endemic in the rural locality of Odisha and a significant proportion of severe malaria causes acute renal complication, there is no definite study on the survival of malarial acute kidney injury (AKI) in children of the setup of the current study. Objective: The objective of the study was to find out the survival of malarial AKI in children. Methods: A prospective analytical study was conducted from October 2016 to September 2018 in the postgraduate department of pediatrics, of a tertiary care hospital in Odisha, after approval from the Institutional Ethics Committee. Children with smear-positive and/or quantitative buffy coat (QBC) positive malaria were included in the study. All the relevant data (age, gender, duration of hospital stays, stages of AKI, signs, and symptoms of AKI, serum urea and creatinine, electrolytes, and routine hemogram) were collected, validated and results were analyzed in terms of one-way ANOVA and Kaplan–Meier survival analysis. Results: Out of 202 malarial cases, 50.4% (102) cases were found to be suffering from malarial AKI. Out of 102 malarial AKI children, 68% were affected due to falciparum infection, 12% due to vivax, and rest 20% due to mixed infection. The median duration of survival in days between three stages of AKI was significant as evidenced by Tarone-Ware Chi-square=48.365 (df=2), p=0.000. Conclusion: Mortality was 6% and all of these deaths belong to Stage 3 AKI; furthermore, the morbidities are more in Stage 3 as compared to other stages

Removing barriers to emergency medicine point-of-care ultrasound: Illustrated by a roadmap for emergency medicine point-of-care ultrasound expansion in India

Point-of-care ultrasound (PoCUS) has a potentially vital role to play in emergency medicine (EM), whether it be in high-, medium-, or low-resourced settings. However, numerous barriers are present which impede EM PoCUS implementation nationally and globally: (i) lack of a national practice guideline or scope of practice for EM PoCUS, (ii) resistance from non-PoCUS users of ultrasound imaging (USI) and lack of awareness from those who undertake parallel or post-EM patient care, and (iii) heterogeneous pattern of resources available in different institutes and settings. When combined with the Indian Preconception and Prenatal Diagnostic Techniques (PCPNDT) Act, this has led to the majority of India’s 1.4 billion citizens being unable to access EM PoCUS. In order to address these barriers (globally as well as with specific application to India), this article outlines the three core principles of EM PoCUS: (i) the remit of the EM PoCUS USI must be well defined a priori, (ii) the standard of EM PoCUS USI must be the same as that of non-PoCUS users of USI, and (iii) the imaging performed should align with subsequent clinical decision-making and resource availability. These principles are contextualized using an integrated PoCUS framework approach which is designed to provide a robust foundation for consolidation and expansion across different PoCUS specialisms and health-care settings. Thus, a range of mechanisms (from optimization of clinical practice through to PoCUS educational reform) are presented to address such barriers. For India, these are combined with specific mechanisms to address the PCPNDT Act, to provide the basis for influencing national legislation and instigating an addendum to the Act. By mapping to the recent Lancet Commission publication on transforming access to diagnostics, this provides a global and cross-discipline perspective for the recommendations

Integration of point-of-care ultrasound during rapid sequence intubation in trauma resuscitation

Introduction: Airway and breathing management play critical role in trauma resuscitation. Early identification of esophageal intubation and detection of fatal events is critical. Authors studied the utility of integration of point-of-care ultrasound (POCUS) during different phases of rapid sequence intubation (RSI) in trauma resuscitation. Methods: It was prospective, randomized single-centered study conducted at the Emergency Department of a level one trauma center. Patients were divided into ultrasonography (USG) and clinical examination (CE) arm. The objectives were to study the utility of POCUS in endotracheal tube placement and confirmations and identification of potentially fatal conditions as tracheal injury, midline vessels, paratracheal hematoma, vocal cord pathology, pneumothorax, and others during RSI. Patient >1 year of age were included. Time taken for procedure, number of incorrect intubations, and pathologies detected were noted. The data were collected in Microsoft Excel spread sheets and analyzed using Stata (version 11.2, Stata Corp, Texas, U. S. A) software. Results: One hundred and six patients were recruited. The mean time for primary survey USG versus CE arm was (20 ± 10.01 vs. 18 ± 11.03) seconds. USG detected four pneumothorax, one tracheal injury, and one paratracheal hematoma. The mean procedure time USG versus CE arm was (37.3 ± 21.92 vs. 58 ± 32.04) seconds. Eight esophageal intubations were identified in USG arm by POCUS and two in CE arm by EtCO2 values. Conclusion: Integration of POCUS was useful in all three phases of RSI. It identified paratracheal hematoma, tracheal injury, and pneumothorax. It also identified esophageal intubation and confirmed main stem tracheal intubation in less time compared to five-point auscultation and capnography