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1.
Nature ; 615(7952): 418-424, 2023 03.
Article in English | MEDLINE | ID: mdl-36922612

ABSTRACT

Chirality is a geometrical property described by continuous mathematical functions1-5. However, in chemical disciplines, chirality is often treated as a binary left or right characteristic of molecules rather than a continuity of chiral shapes. Although they are theoretically possible, a family of stable chemical structures with similar shapes and progressively tuneable chirality is yet unknown. Here we show that nanostructured microparticles with an anisotropic bowtie shape display chirality continuum and can be made with widely tuneable twist angle, pitch, width, thickness and length. The self-limited assembly of the bowties enables high synthetic reproducibility, size monodispersity and computational predictability of their geometries for different assembly conditions6. The bowtie nanoassemblies show several strong circular dichroism peaks originating from absorptive and scattering phenomena. Unlike classical chiral molecules, these particles show a continuum of chirality measures2 that correlate exponentially with the spectral positions of the circular dichroism peaks. Bowtie particles with variable polarization rotation were used to print photonically active metasurfaces with spectrally tuneable positive or negative polarization signatures for light detection and ranging (LIDAR) devices.

2.
Proc Natl Acad Sci U S A ; 121(13): e2310469121, 2024 Mar 26.
Article in English | MEDLINE | ID: mdl-38502692

ABSTRACT

The incessant mutations of viruses, variable immune responses, and likely emergence of new viral threats necessitate multiple approaches to novel antiviral therapeutics. Furthermore, the new antiviral agents should have broad-spectrum activity and be environmentally stable. Here, we show that biocompatible tapered CuS nanoparticles (NPs) efficiently agglutinate coronaviruses with binding affinity dependent on the chirality of surface ligands and particle shape. L-penicillamine-stabilized NPs with left-handed curved apexes display half-maximal inhibitory concentrations (IC50) as low as 0.66 pM (1.4 ng/mL) and 0.57 pM (1.2 ng/mL) for pseudo-type SARS-CoV-2 viruses and wild-type Wuhan-1 SARS-CoV-2 viruses, respectively, which are about 1,100 times lower than those for antibodies (0.73 nM). Benefiting from strong NPs-protein interactions, the same particles are also effective against other strains of coronaviruses, such as HCoV-HKU1, HCoV-OC43, HCoV-NL63, and SARS-CoV-2 Omicron variants with IC50 values below 10 pM (21.8 ng/mL). Considering rapid response to outbreaks, exposure to elevated temperatures causes no change in the antiviral activity of NPs while antibodies are completely deactivated. Testing in mice indicates that the chirality-optimized NPs can serve as thermally stable analogs of antiviral biologics complementing the current spectrum of treatments.


Subject(s)
COVID-19 , Coronavirus OC43, Human , Humans , Animals , Mice , SARS-CoV-2/genetics , Antibodies/pharmacology , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use
3.
Genes Chromosomes Cancer ; 63(6): e23250, 2024 06.
Article in English | MEDLINE | ID: mdl-38884183

ABSTRACT

INTRODUCTION: Urachal cancer (UC) is a rare genitourinary malignancy arising from the urachus, an embryonic remnant of the placental allantois. Its diagnosis remains ambiguous with late-stage cancer detection and represents a highly aggressive disease. Due to its rarity, there is no clear consensus on molecular signatures and appropriate clinical management of UC. CASE REPORT: We report a 45-year-old man with recurrent urachal adenocarcinoma (UA) treated with cystectomies, chemotherapy, and radiotherapy. The patient initially presented with hematuria and abdominal pain. Imaging revealed a nodular mass arising from the superior wall of the urinary bladder and extending to the urachus. Biopsy results suggested moderately differentiated UA with muscle layer involvement. The tumor recurred after 20 months, following which, another partial cystectomy was performed. Repeat progression was noted indicating highly aggressive disease. Targeted next-generation sequencing revealed the presence of EIF3E::RSPO2 fusion, along with BRAF and TP53 mutations, and EGFR gene amplification. This is the first case reporting the presence of this fusion in UA. Palliative medication and radiotherapy were administered to manage the disease. CONCLUSION: Current treatment modality of surgery may be effective in the early stages of recurrent UA; however, a standard chemotherapy and radiotherapy regimen is yet to be determined for advanced stages. The detection of the rare EIF3E::RSPO2 fusion warrants further studies on the significance of this variant as a possible therapeutic target for improved clinical management.


Subject(s)
Adenocarcinoma , Urinary Bladder Neoplasms , Humans , Male , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/pathology , Middle Aged , Adenocarcinoma/genetics , Adenocarcinoma/pathology , Neoplasm Recurrence, Local/genetics , Neoplasm Recurrence, Local/pathology , Eukaryotic Initiation Factor-3/genetics , Oncogene Proteins, Fusion/genetics
4.
Small ; : e2307610, 2024 Feb 11.
Article in English | MEDLINE | ID: mdl-38342695

ABSTRACT

Borophene, a 2D material exhibiting unique crystallographic phases like the anisotropic atomic lattices of ß12 and X3 phases, has attracted considerable attention due to its intriguing Dirac nature and metallic attributes. Despite surpassing graphene in electronic mobility, borophene's potential in energy storage and catalysis remains untapped due to its inherent electrochemical and catalytic limitations. Elemental doping emerges as a promising strategy to introduce charge carriers, enabling localized electrochemical and catalytic functionalities. However, effective doping of borophene has been a complex and underexplored challenge. Here, an innovative, one-pot microwave-assisted doping method, tailored for the ß12 phase of borophene is introduced. By subjecting dispersed ß12 borophene in dimethylformamide to controlled microwave exposure with sulfur powder and FeCl3 as doping precursors, S- and Fe doping in borophene can be controlled. Employing advanced techniques including high-resolution transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, confirm successful sulfur and iron dopant incorporation onto ß12 borophene is confirmed, achieving doping levels of up to 11 % and 13 %, respectively. Remarkably, S- and Fe-doped borophene exhibit exceptional supercapacitive behavior, with specific capacitances of 202 and 120 F g-1 , respectively, at a moderate current density of 0.25 A g-1 .

5.
Small ; : e2404337, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38958089

ABSTRACT

Monoelemental atomic sheets (Xenes) and other 2D materials offer record electronic mobility, high thermal conductivity, excellent Young's moduli, optical transparency, and flexural capability, revolutionizing ultrasensitive devices and enhancing performance. The ideal synthesis of these quantum materials should be facile, fast, scalable, reproducible, and green. Microwave expansion followed by cryoquenching (MECQ) leverages thermal stress in graphite to produce high-purity graphene within minutes. MECQ synthesis of graphene is reported at 640 and 800 W for 10 min, followed by liquid nitrogen quenching for 5 and 90 min of sonication. Microscopic and spectroscopic analyses confirmed the chemical identity and phase purity of monolayers and few-layered graphene sheets (200-12 µm). Higher microwave power yields thinner layers with enhanced purity. Molecular dynamics simulations and DFT calculations support the exfoliation under these conditions. Electrostatic droplet switching is demonstrated using MECQ-synthesized graphene, observing electrorolling of a mercury droplet on a BN/graphene interface at voltages above 20 V. This technique can inspire the synthesis of other 2D materials with high purity and enable new applications.

6.
Arch Microbiol ; 206(2): 77, 2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38270599

ABSTRACT

Hands are the primary mode of transmission of microbe-based infections, as they harbor normal microbiota and pathogenic microbes. SARS-CoV-2 has endangered lives worldwide, and WHO has recommended good hygiene practices, especially hand hygiene. In addition, other infectious diseases like diphtheria, measles, tuberculosis, HIV, malaria, etc. are spreading in the shadow of the COVID-19 pandemic. The anti-microbial efficiency of two in-house developed herbal-alcohol based hand sanitizers containing Azadirachta indica, Citrus limon, Zingiber officinale, and Aloe vera (HS1) and Zingiber officinale replaced with Ocimum sanctum (HS2) was evaluated. HS1, with Zingiber officinale, and HS2, with Ocimum sanctum, herbal sanitizers showcased in-vitro anti-viral activity on MDCK cells using the reference strain of influenza A virus, A/PR/8/34 (H1N1), and reduced 99.99% of microbial load within 30 s of contact time, estimated by the Antimicrobial Susceptibility Testing Method. On volunteers, HS1 and HS2 were more effective than alcohol-based WHO sanitizers. Moreover, HS2 sanitizer is more effective against viruses and has better efficiency and hedonic qualities in volunteers than HS1. These sanitizers don't irritate or dry up the skin and have a longer shelf life. Overall, findings reveal that herbal-alcohol-based sanitizers are promising hand hygiene products with the capability of reducing microbial load.


Subject(s)
COVID-19 , Citrus , Influenza A Virus, H1N1 Subtype , Humans , Pandemics , Ethanol
7.
Org Biomol Chem ; 22(5): 1010-1017, 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38186335

ABSTRACT

Piperidines are one of the most widely used building blocks in the synthesis of pharmaceutical and agrochemical compounds. The hydrogenation of pyridines is a convenient method to synthesise such compounds as it only requires reactant, catalyst, and a hydrogen source. However, this reaction still remains difficult for the reduction of functionalised and multi-substituted pyridines. Here we report the use of a stable, commercially available rhodium compound, Rh2O3, for the reduction of various unprotected pyridines. The reaction only requires mild conditions, and the substrate scope is broad, making it practically useful.

8.
J Fluoresc ; 2024 Mar 16.
Article in English | MEDLINE | ID: mdl-38492176

ABSTRACT

In this paper, a new class of two component white light emitting systems viz, JaB (java plum + beetroot) {I}, and CaB (carrot + beetroot) {II} were developed through resonance energy transfer (RET) phenomenon by using a fruit (java plum) and two vegetable (carrot and beetroot) extracts. In these white light emitting systems, java plum and carrot are the donors while beetroot is the acceptor. The primary fluorescent pigments present in the natural extracts (i.e., anthocyanin in java plum, ß-carotene in carrot, and betanin in beetroot) were responsible for the white light emission. The CIE (Commission Internationale d'Eclairage) coordinates for I and II were {0.32, 0.34} and {0.33, 0.33}, respectively, in solution phase. Interestingly, the white light emission (WLE) was also achieved in agar-agar gel medium. In gel medium, the CIE values were {0.31, 0.34} and {0.33, 0.32} for I and II, respectively. The donor-acceptor distance (r) for I and II were found to be 0.5 and 0.4 nm, respectively. Furthermore, the rate of energy transfer was also quantified with the values of 2.78 × 109 s-1 for JaB (I) and 1.02 × 108 s-1 for CaB (II) systems. The mechanistic investigation of the two white light systems was further supported by DFT studies.

9.
Environ Res ; 249: 118332, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38331146

ABSTRACT

This study evaluates the groundwater potential and quality in the parts of Chhotanagpur Gneissic Complex situated in the East Indian Shield. The region has faced groundwater development challenges for several decades. Therefore, in the study area, it is crucial to address the depletion of both groundwater quality and quantity, as this facilitates the identification of potential uncontaminated groundwater zones. The present study interprets the groundwater potential zones (GWPZ) utilizing an analytical hierarchical process (AHP) integrated with hydrogeochemical analysis. Several thematic maps were prepared to delineate the GPWZ. It has been found that ∼0.6% of the study area has a very good potential zone, 14.4% has good, 52% has moderate, and approximately 32% and 0.9% have low to very low prospective groundwater resources, respectively. The authentication of results was found to be excellent (91.4%) with the Area Under Curve (AUC). Analysis of hydrogeochemical data suggests that Mixed Ca-Na-HCO3, Mixed Ca-Mg-Cl, Ca-HCO3, and Na-Cl are the dominant water types in the study area. The principal component analysis suggests that Na+, Mg2+, Cl-, NO3-, and SO42- significantly contribute to groundwater chemistry. The K-means clustering and hierarchical cluster analysis classified groundwater samples into three clusters based on the hydrogeochemical characteristics. It is inferred that silicate weathering and reverse ion reactions through rock-water interaction control geogenic processes for groundwater chemistry. It is also inferred that regions with poor to unsuitable water quality indexes also have low GWPZ. Further, groundwater for irrigation is also accessed and found unsuitable at some locations. This research contributes to comprehending groundwater characteristics in analogous geological regions globally. Additionally, it assists in implementing preventive actions to mitigate groundwater contamination, consequently lowering health risks and formulating sustainable plans for the future.


Subject(s)
Environmental Monitoring , Groundwater , Water Pollutants, Chemical , Groundwater/chemistry , Groundwater/analysis , India , Water Pollutants, Chemical/analysis
10.
Sci Technol Adv Mater ; 25(1): 2357062, 2024.
Article in English | MEDLINE | ID: mdl-38835629

ABSTRACT

Affordable and environmentally friendly electrochemically active raw energy storage materials are in high demand to switch to mass-scale renewable energy. One particularly promising avenue is the feasibility of utilizing food waste-derived nanoporous carbon. This material holds significance due to its widespread availability, affordability, ease of processing, and, notably, its cost-free nature. Over the years, various strategies have been developed to convert different food wastes into nanoporous carbon materials with enhanced electrochemical properties. The electrochemical performance of these materials is influenced by both intrinsic factors, such as the composition of elements derived from the original food sources and recipes, and extrinsic factors, including the conditions during pyrolysis and activation. While current efforts are dedicated to optimizing process parameters to achieve superior performance in electrochemical energy storage devices, it is timely to take stock of the current state of research in this emerging field. This review provides a comprehensive overview of recent developments in the fabrication and surface characterisation of porous carbons from different food wastes. A special focus is given on the applications of these food waste derived porous carbons for energy storage applications including batteries and supercapacitors.


This review compiles very recent literature on the synthesis of porous carbon from food waste biomass and their efficient utilisation as electrode material for energy storage applications in supercapacitor devices.

11.
Chem Soc Rev ; 52(21): 7602-7664, 2023 Oct 30.
Article in English | MEDLINE | ID: mdl-37830178

ABSTRACT

Catalysis is at the heart of modern-day chemical and pharmaceutical industries, and there is an urgent demand to develop metal-free, high surface area, and efficient catalysts in a scalable, reproducible and economic manner. Amongst the ever-expanding two-dimensional materials family, carbon nitride (CN) has emerged as the most researched material for catalytic applications due to its unique molecular structure with tunable visible range band gap, surface defects, basic sites, and nitrogen functionalities. These properties also endow it with anchoring capability with a large number of catalytically active sites and provide opportunities for doping, hybridization, sensitization, etc. To make considerable progress in the use of CN as a highly effective catalyst for various applications, it is critical to have an in-depth understanding of its synthesis, structure and surface sites. The present review provides an overview of the recent advances in synthetic approaches of CN, its physicochemical properties, and band gap engineering, with a focus on its exclusive usage in a variety of catalytic reactions, including hydrogen evolution reactions, overall water splitting, water oxidation, CO2 reduction, nitrogen reduction reactions, pollutant degradation, and organocatalysis. While the structural design and band gap engineering of catalysts are elaborated, the surface chemistry is dealt with in detail to demonstrate efficient catalytic performances. Burning challenges in catalytic design and future outlook are elucidated.

12.
Int Tinnitus J ; 27(2): 231-237, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-38507639

ABSTRACT

Schizophrenia, a complex neuropsychiatric condition, manifests with severe neurobiological and psychosocial symptoms, including psychosis, cognitive dysfunction, and social withdrawal. Neuroscience links these symptoms to synaptic malfunctions and neurotransmitter dysregulation, leading to a profound disconnection from reality. The disorder significantly affects cognitive, affective, and behavioral functions, causing considerable neuropsychological distress and functional impairments. The interplay of schizophrenia with the criminal justice system is complex, often exacerbating psychiatric stigma and introducing challenging neuroethical dilemmas. From neuroscientific perspective, schizophrenia symptoms are classified into 'positive' (hyperfunctioning or distortion of normal mental processes) and 'negative' (reduction or loss of mental functions). Each category presents distinct medico-legal challenges. Studies, including those from the Clinical Antipsychotic Trials of Intervention Effectiveness, highlight the importance of identifying neurobiological and psychosocial factors that increase the risk of criminal justice involvement, stressing the necessity of addressing concurrent disorders like substance use disorders. This convergence underscores the need for a delicate balance between therapeutic interventions and legal responsibility, advocating for policy reforms and neuroscience-based research initiatives. Such efforts are crucial for improving the management of schizophrenia within the criminal justice system, focusing on both the medical and societal aspects of the disorder.


Subject(s)
Schizophrenia , Substance-Related Disorders , Humans , Schizophrenia/epidemiology , Schizophrenia/therapy , Criminal Law
13.
Int Tinnitus J ; 27(2): 225-230, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-38512870

ABSTRACT

This paper delves into the intricate realm of mental health issues within prisons including other correctional facilities, the intersectionality with legal and medical aspects, and the potential of pharmacology as a viable treatment modality. The prevalence and diverse array of mental disorders among incarcerated individuals are thoroughly examined, underscoring the imperative for all-encompassing interventions. The legal structure, hurdles encountered in delivering mental healthcare, and the indispensability of interdisciplinary cooperation are scrutinized. Furthermore, the effectiveness and moral implications of pharmaceutical interventions in correctional environments are deliberated upon. Conclusive suggestions are put forth to enhance mental healthcare provisions in prisons. The research paper endeavors to penetrate the labyrinthine complexities of mental health predicaments within correctional institutions, with a specific emphasis on the convergence of medico-legal facets and the plausible impact of pharmacological interventions. The study strives to elucidate the intricate nature of mental health challenges among incarcerated populations, considering the intricate interplay of socio-cultural, environmental, and psychological factors that contribute to their pervasiveness. By delving into these interconnected dimensions, the research aims to unlock prospective remedies capable of efficaciously meeting the mental health requisites of incarcerated individuals.


Subject(s)
Mental Disorders , Prisoners , Humans , Prisons , Mental Health , Prospective Studies , Prisoners/psychology , Mental Disorders/drug therapy , Mental Disorders/epidemiology
14.
J Anaesthesiol Clin Pharmacol ; 40(1): 69-74, 2024.
Article in English | MEDLINE | ID: mdl-38666183

ABSTRACT

Background and Aims: The present study was conducted to determine the optimal dose of cisatracurium for intubating conditions and onset and offset of neuromuscular blockade. Data in Indian population are scarce, and hence, the present study was planned to evaluate different doses of cisatracurium. Material and Methods: The prospective randomized double-blind study was conducted on 180 patients of either sex in the age group of 20-60 yrs., having physical status class I to III, scheduled for surgery under general anesthesia. After exclusion 154 patients were randomly divided into three groups comprising 52, 51, and 51, respectively, in Group A, Group B, and group C. They received 0.1 mgkg-1, 0.2 mgkg-1, and 0.3 mgkg-1 of cisatracurium, respectively, to facilitate endotracheal intubation. Time of onset, intubating conditions, hemodynamic parameters, signs of histamine release, and recovery time were noted. Results: Mean time to onset was maximum in group A (4.37 ± 0.48 minutes) and minimum in group C (2.33 ± 0.43 minutes). Intubating conditions were found excellent in 88% patients in group. Change in HR was found to be non-significant at all time periods, but decrease in MAP was found between 2 and 10 minutes in group C. Duration of action was longest in group C. Conclusion: We conclude that cisatracurium in dose of 0.2 mgkg-1 and 0.3 mgkg-1 provides good-to-excellent intubating conditions within less than 3 minutes.

15.
J Anaesthesiol Clin Pharmacol ; 40(1): 43-47, 2024.
Article in English | MEDLINE | ID: mdl-38666157

ABSTRACT

Background and Aims: Primary aim of the study was to evaluate the performance of Intubating LMA (ILMA) and blockbuster LMA in terms of first pass success rate, ease and duration taken for blind tracheal intubation. Material and Methods: The present prospective randomised study was conducted on 70 patients of either sex aged 18-60 years belonging to ASA physical status I or II. Patients were randomly allocated to either, group I and group B of n = 35 each. In group I and B patients were intubated using ILMA and LMA BlockBuster respectively. Insertion time and ease of placement of supraglottic device, total time taken for successful intubation, number of attempts for endotracheal tube (ETT) placement, and ease of placement of ETT, were recorded. Results: In both groups, the supraglottic device was placed on the first attempt in 88.6% patients. The first-attempt success rate for ETT placement was 71.4% in group I versus 94.3% in group B, (P = 0.01) with an overall success rate of 88.5% in group I and 100% in group. More failure rate was observed in group I (11.4%) compared to group B (0%). The total time taken for successful intubation in group I was 11.53 ± 6.410 sec and 9.17 ± 2.749 sec in group B (P = 0.04). Conclusion: We conclude that the modifications in the design of LMA Blockbuster (>95° angle, availability of the parker flex tube 27-30°angle of the emergence of airway tube) make it a more convenient, effective, simpler, and faster intubating device than ILMA.

16.
J Anaesthesiol Clin Pharmacol ; 40(1): 101-107, 2024.
Article in English | MEDLINE | ID: mdl-38666159

ABSTRACT

Background and Aim: Intubation with Macintosh requires flexing the lower cervical spine and extending the atlanto-occipital joint to create a "line of sight." Primary aim of study was to compare the extent of cervical spine movement during laryngoscopy using conventional Macintosh laryngoscope and Airtraq. Material and Methods: A total of 25 patients of either sex between the age group of 18 and 60 years, having American Society of Anesthesiologists (ASA) physical status of Grade-I and Grade-II, scheduled for elective surgery under image control requiring general anesthesia and intubation were enrolled. A baseline image of the lateral cervical spine including the first four cervical vertebrae was taken by an image intensifier. After administration of general anesthesia, laryngoscopy was first performed using a Macintosh laryngoscope and a second X-ray image of the lateral cervical spine was taken. The second laryngoscopy using a Airtraq laryngoscope was done and the third image of the lateral cervical spine was taken. Angles between occiput and C1; C1 and C2; C2 and C3; C3 and C4; and occiput and C4 were calculated. Atlanto-occipital distance (AOD) was calculated as the distance between occiput and C1. Results: Macintosh showed greater cervical movement as compared with Airtraq but a significant difference in the movement was observed at C2-C3 and C0-C4. Baseline mean AOD was 2.21 ± 1.25 mm, after Macintosh and Airtraq laryngoscopy was found to be 1.13 ± 0.60 and 1.6 ± 0.78 mm, respectively, and was found to be significant (P < 0.05). Conclusion: We conclude that Airtraq allows intubation with less movement of the upper cervical spine makes Airtraq preferred equipment for intubation in patients with a potential cervical spine injury.

17.
Small ; 19(17): e2207181, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36693792

ABSTRACT

Carbon-based quantum dots (QDs) have emerged as a fascinating class of advanced materials with a unique combination of optoelectronic, biocompatible, and catalytic characteristics, apt for a plethora of applications ranging from electronic to photoelectrochemical devices. Recent research works have established carbon-based QDs for those frontline applications through improvements in materials design, processing, and device stability. This review broadly presents the recent progress in the synthesis of carbon-based QDs, including carbon QDs, graphene QDs, graphitic carbon nitride QDs and their heterostructures, as well as their salient applications. The synthesis methods of carbon-based QDs are first introduced, followed by an extensive discussion of the dependence of the device performance on the intrinsic properties and nanostructures of carbon-based QDs, aiming to present the general strategies for device designing with optimal performance. Furthermore, diverse applications of carbon-based QDs are presented, with an emphasis on the relationship between band alignment, charge transfer, and performance improvement. Among the applications discussed in this review, much focus is given to photo and electrocatalytic, energy storage and conversion, and bioapplications, which pose a grand challenge for rational materials and device designs. Finally, a summary is presented, and existing challenges and future directions are elaborated.

18.
Chemphyschem ; 24(24): e202300447, 2023 Dec 14.
Article in English | MEDLINE | ID: mdl-37732481

ABSTRACT

Beyond a critical doping level, Ag-2D TiO2 sheets (ATO) are deemed to be a flexible transparent conductor, useful for visible-range functional photonic/optoelectronic devices/sensors, sunlight-sensitive catalysis, and light-activated resistive switching. Due to the lack of control of surface energy which often leads to the formation of structural defects and even dimensionality crossover (2D to 0D) of materials during doping reaction, it is challenging to obtain ATO with a controlled doping level. Gauging the urgency, therefore we report the surface energy-controlled synthesis of ATO employing liquid phase exfoliation of TiO2 and subsequent hydrothermal Ag-doping in the presence of Hexamethylenetetramine (HMTA). Electron microscopy and atomic force microscopy reveal ATO sheets with large lateral dimensions. 6-fold, 4-fold, and strain-mediated crystallographic phases of 2D ATO have been revealed by high-resolution electron imaging. Successful tuning of the band gap down to ~2 eV with Ag doping up to ~10 % is obtained. Synthesized 2D ATO have been investigated for their electrical, optical, optoelectronic, photoluminescence, and ferromagnetic behaviour. Visible light-sensitive thermally/structurally robust semiconductor/conductor via tuneable doping will pave the way for their flexible as well as wearable device applications. Self-healing effect of AFM tip-generated mechanical stress has also been demonstrated.

19.
Environ Sci Technol ; 57(41): 15401-15411, 2023 10 17.
Article in English | MEDLINE | ID: mdl-37789620

ABSTRACT

Low-cost sensors (LCSs) for measuring air pollution are increasingly being deployed in mobile applications, but questions concerning the quality of the measurements remain unanswered. For example, what is the best way to correct LCS data in a mobile setting? Which factors most significantly contribute to differences between mobile LCS data and those of higher-quality instruments? Can data from LCSs be used to identify hotspots and generate generalizable pollutant concentration maps? To help address these questions, we deployed low-cost PM2.5 sensors (Alphasense OPC-N3) and a research-grade instrument (TSI DustTrak) in a mobile laboratory in Boston, MA, USA. We first collocated these instruments with stationary PM2.5 reference monitors (Teledyne T640) at nearby regulatory sites. Next, using the reference measurements, we developed different models to correct the OPC-N3 and DustTrak measurements and then transferred the corrections to the mobile setting. We observed that more complex correction models appeared to perform better than simpler models in the stationary setting; however, when transferred to the mobile setting, corrected OPC-N3 measurements agreed less well with the corrected DustTrak data. In general, corrections developed by using minute-level collocation measurements transferred better to the mobile setting than corrections developed using hourly-averaged data. Mobile laboratory speed, OPC-N3 orientation relative to the direction of travel, date, hour-of-the-day, and road class together explain a small but significant amount of variation between corrected OPC-N3 and DustTrak measurements during the mobile deployment. Persistent hotspots identified by the OPC-N3s agreed with those identified by the DustTrak. Similarly, maps of PM2.5 distribution produced from the mobile corrected OPC-N3 and DustTrak measurements agreed well. These results suggest that identifying hotspots and developing generalizable maps of PM2.5 are appropriate use-cases for mobile LCS data.


Subject(s)
Air Pollutants , Air Pollution , Environmental Pollutants , Air Pollutants/analysis , Environmental Monitoring/methods , Air Pollution/analysis , Particulate Matter/analysis
20.
J Phys Chem A ; 127(34): 7241-7255, 2023 Aug 31.
Article in English | MEDLINE | ID: mdl-37597243

ABSTRACT

In this contribution, we assess the computational machinery to calculate the phosphorescence properties of a large pool of heteroleptic [Ir(C^N)2(N^N)]+ complexes (where N^N is an ancillary ligand and C^N is a cyclometalating ligand) including their phosphorescent rates and their emission spectra. Efficient computational protocols are next proposed. Specifically, different flavors of DFT functionals were benchmarked against DLPNO-CCSD(T) for the phosphorescence energies. The transition density matrix and decomposition analysis of the emitting triplet excited state enable us to categorize the studied complexes into different cases, from predominant triplet ligand-centered (3LC) character to predominant charge-transfer (3CT) character, either of metal-to-ligand charge transfer (3MLCT), ligand-to-ligand charge transfer (3LLCT), or a combination of the two. We have also calculated the vibronically resolved phosphorescent spectra and rates. Ir(III) complexes with predominant 3CT character are characterized by less vibronically resolved bands as compared to those with predominant 3LC character. Furthermore, some of the complexes are characterized by close-lying triplet excited states so that the calculation of their phosphorescence properties poses additional challenges. In these scenarios, it is necessary to perform geometry optimizations of higher-lying triplet excited states (i.e., Tn). We demonstrate that in the latter scenarios all of the close-lying triplet species must be considered to recover the shape of the experimental emission spectra. The global analysis of computed emission energies, shape of the computed emission spectra, computed rates, etc. enable us to unambiguously pinpoint for the first time the triplet states involved in the emission process and to provide a general classification of Ir(III) complexes with regard to their phosphorescence properties.

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