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1.
Nature ; 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38862026

RESUMO

Human spaceflight has historically been managed by government agencies, such as the NASA Twins Study1, but new commercial spaceflight opportunities have opened spaceflight to a broader population. In 2021, the SpaceX Inspiration4 mission launched the first-ever all civilian crew to low Earth orbit, which included the youngest American astronaut (age 29), novel in-flight experimental technologies (handheld ultrasound imaging, smartwatch wearables, and immune profiling), ocular alignment measurements, and new protocols for in-depth, multi-omic molecular and cellular profiling. Here we report the primary findings from the 3-day spaceflight mission, which induced a broad range of physiological and stress responses, neurovestibular changes indexed by ocular misalignment, and altered neurocognitive functioning, some of which match long-term spaceflight2, but almost all of which did not differ from baseline (pre-flight) after return to Earth. Overall, these preliminary civilian spaceflight data suggest that short-duration missions do not pose a significant health risk, and moreover present a rich opportunity to measure the earliest phases of adaptation to spaceflight in the human body at anatomical, cellular, physiologic, and cognitive levels. Finally, these methods and results lay the foundation for an open, rapidly expanding biomedical database for astronauts3, which can inform countermeasure development for both private and government-sponsored space missions.

2.
Nature ; 576(7787): 423-428, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31853081

RESUMO

Magnetically doped topological insulators enable the quantum anomalous Hall effect (QAHE), which provides quantized edge states for lossless charge-transport applications1-8. The edge states are hosted by a magnetic energy gap at the Dirac point2, but hitherto all attempts to observe this gap directly have been unsuccessful. Observing the gap is considered to be essential to overcoming the limitations of the QAHE, which so far occurs only at temperatures that are one to two orders of magnitude below the ferromagnetic Curie temperature, TC (ref. 8). Here we use low-temperature photoelectron spectroscopy to unambiguously reveal the magnetic gap of Mn-doped Bi2Te3, which displays ferromagnetic out-of-plane spin texture and opens up only below TC. Surprisingly, our analysis reveals large gap sizes at 1 kelvin of up to 90 millielectronvolts, which is five times larger than theoretically predicted9. Using multiscale analysis we show that this enhancement is due to a remarkable structure modification induced by Mn doping: instead of a disordered impurity system, a self-organized alternating sequence of MnBi2Te4 septuple and Bi2Te3 quintuple layers is formed. This enhances the wavefunction overlap and size of the magnetic gap10. Mn-doped Bi2Se3 (ref. 11) and Mn-doped Sb2Te3 form similar heterostructures, but for Bi2Se3 only a nonmagnetic gap is formed and the magnetization is in the surface plane. This is explained by the smaller spin-orbit interaction by comparison with Mn-doped Bi2Te3. Our findings provide insights that will be crucial in pushing lossless transport in topological insulators towards room-temperature applications.

3.
Phys Chem Chem Phys ; 26(14): 11056-11063, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38529535

RESUMO

In this work, employing first-principles calculations, we systematically investigate the atomic structure and electronic and optical properties of the AgTe monolayer, as well as the impact of alkali metal (Li, Na, K) and alkaline earth metal (Be, Mg, Ca) atoms decoration. The AgTe monolayer exhibits metallic characteristics. When Li, Na, K, and Mg atoms are decorated on the AgTe monolayer, the decorated AgTe monolayers are dynamically stable. In contrast, with Be and Ca atoms, the decorated structures are found to be dynamically unstable. Interestingly, the decoration of Li, Na, and K atoms into the AgTe monolayer can open the band gaps in the decorated Li-, Na- and K-AgTe monolayers around the Fermi level, leading to the actualization of metal-to-semiconductor transitions. In contrast, the decorated Mg-AgTe monolayer maintains its metallic characteristic. The highest electron and hole mobilities are achieved in the Na-AgTe monolayer among the decorated structures, suggesting the applicability of this structure in photovoltaic applications. The optical study shows that Li-, Na- and K-decorated AgTe monolayers have improved light absorption in the visible light region. Consequently, our findings shed light on the decoration of these 2D material monolayers and can potentially enhance and motivate studies in producing these monolayers for current nanodevices and future applications.

4.
Indian J Med Res ; 159(1): 91-101, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38344919

RESUMO

BACKGROUND OBJECTIVES: The clinical course of COVID-19 and its prognosis are influenced by both viral and host factors. The objectives of this study were to develop a nationwide platform to investigate the molecular epidemiology of SARS-CoV-2 (Severe acute respiratory syndrome Corona virus 2) and correlate the severity and clinical outcomes of COVID-19 with virus variants. METHODS: A nationwide, longitudinal, prospective cohort study was conducted from September 2021 to December 2022 at 14 hospitals across the country that were linked to a viral sequencing laboratory under the Indian SARS-CoV-2 Genomics Consortium. All participants (18 yr and above) who attended the hospital with a suspicion of SARS-CoV-2 infection and tested positive by the reverse transcription-PCR method were included. The participant population consisted of both hospitalized as well as outpatients. Their clinical course and outcomes were studied prospectively. Nasopharyngeal samples collected were subjected to whole genome sequencing to detect SARS-CoV-2 variants. RESULTS: Of the 4972 participants enrolled, 3397 provided samples for viral sequencing and 2723 samples were successfully sequenced. From this, the evolution of virus variants of concern including Omicron subvariants which emerged over time was observed and the same reported here. The mean age of the study participants was 41 yr and overall 49.3 per cent were female. The common symptoms were fever and cough and 32.5 per cent had comorbidities. Infection with the Delta variant evidently increased the risk of severe COVID-19 (adjusted odds ratio: 2.53, 95% confidence interval: 1.52, 4.2), while Omicron was milder independent of vaccination status. The independent risk factors for mortality were age >65 yr, presence of comorbidities and no vaccination. INTERPRETATION CONCLUSIONS: The authors believe that this is a first-of-its-kind study in the country that provides real-time data of virus evolution from a pan-India network of hospitals closely linked to the genome sequencing laboratories. The severity of COVID-19 could be correlated with virus variants with Omicron being the milder variant.


Assuntos
COVID-19 , Feminino , Humanos , Masculino , Progressão da Doença , Hospitais , Estudos Prospectivos , SARS-CoV-2/genética , Adulto , Adolescente , Idoso , Pessoa de Meia-Idade
5.
J Environ Manage ; 354: 120451, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38422573

RESUMO

A morphological oriented highly active Cu2O-Ag-CaWO4 (CAC) nano-heterojunction was fabricated for the visible light driven degradation of rifampicin (RFP). Octahedron shaped Cu2O being a base material, where the Tagetes shaped CaWO4 and Ag were embedded on it. The shape-controlled morphology of Cu2O and CaWO4 as well as Ag decoration influence high degree of adsorption of RFP and interfacial charge transfer between the nano-heterojunction. Further, the larger specific surface area (129.531 m2/g) and narrow band gap energy (2.57 eV) of CAC nano-heterojunction than the controls support the statement. Positively, CAC nano-heterojunction following Z-scheme-type charge transport mechanism attained 96% of RFP degradation within 100 min. O2•- and •OH are the primarily involved reactive oxidation species (ROS) during the photocatalytic reactions, determined by scavenger study and ESR analysis. The stability and reusability of the CAC nano-heterojunction was assessed through performing cyclic experiment of RFP degradation and it holds 96.8% of degradation even after 6th cycle. The stability of CAC nano-heterojunction after photodegradation was further confirmed based on crystalline pattern (XRD analysis) and compositional states (XPS analysis). Intermediates formed during RFP degradation and its toxicity was discovered by using GC-MS/MS and ECOSAR analysis respectively. The end-product toxicity against bacterial system and genotoxicity of CAC nano-heterojunction against Allium cepa were evaluated and the results were seemed to have no negative causes for the aquatic lives.


Assuntos
Rifampina , Espectrometria de Massas em Tandem , Adsorção , Luz , Software
6.
Phys Rev Lett ; 131(6): 065101, 2023 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-37625041

RESUMO

The change in the power balance, temporal dynamics, emission weighted size, temperature, mass, and areal density of inertially confined fusion plasmas have been quantified for experiments that reach target gains up to 0.72. It is observed that as the target gain rises, increased rates of self-heating initially overcome expansion power losses. This leads to reacting plasmas that reach peak fusion production at later times with increased size, temperature, mass and with lower emission weighted areal densities. Analytic models are consistent with the observations and inferences for how these quantities evolve as the rate of fusion self-heating, fusion yield, and target gain increase. At peak fusion production, it is found that as temperatures and target gains rise, the expansion power loss increases to a near constant ratio of the fusion self-heating power. This is consistent with models that indicate that the expansion losses dominate the dynamics in this regime.

7.
Acta Oncol ; 62(11): 1433-1439, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37707506

RESUMO

BACKGROUND: In peripheral lung tumours, stereotactic body radiotherapy (SBRT) is superior to conventional RT. SBRT has also shown high loco-regional control (LC) in centrally located tumours, but there is a high risk of severe toxicity. The STRICTSTARLung trial (NCT05354596) examines if risk-adapted SBRT for central tumours is feasible. In this study, we examined overall survival (OS), Disease-free survival (DSF), LC, and toxicity in patients with central tumours that could have been candidates for SBRT but received conventional RT. MATERIAL AND METHODS: Retrospectively, we evaluated 49 lung cancer patients that between 2008 and 2021 received RT (60-70Gy in 2 Gy fractions) for a solitary tumour or lymph node with a diameter <5cm located <2cm from the bronchial tree, oesophagus, aorta or heart. All tumours were pathologically verified; 30 were primary lung tumours (T1b-T4) and 19 were solitary lymph nodes (T0N1-N2). Chemotherapy was administered as concomitant (29) or sequential (4). OS and LC were analysed using Kaplan Meier. Cox proportional hazards model for OS and disease-free survival (DFS) was performed including tumour volume, histology, sex, T- vs N-site and chemotherapy. Toxicity was scored. RESULTS: In 42 patients, the tumour was located <1 cm to mediastinum. Median follow-up time was 44 months (range: 7-123). The median OS was 51 months. OS at 1-, 3- and 5-year was 88% (SE:5), 59% (SE:7) and 50% (SE:8). Loco-regional recurrences occurred in 16 patients resulting in 1-, and 3-year LC rates of 77% (SE:6) and 64% (SE:8). The majority occurred within 3 years after RT. Only stage showed significant impact on OS and DFS. No patients experienced grade 4-5 toxicity. Seven patients developed grade 3 toxicity (5 oesophageal stenosis, 2 pneumonitis). CONCLUSION: Conventional RT for patients with small central lung tumours or solitary lymph nodes is feasible. Median OS was 51 months, and toxicity was low with no grade 4-5 events.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Radiocirurgia , Humanos , Estudos Retrospectivos , Neoplasias Pulmonares/patologia , Intervalo Livre de Doença , Radiocirurgia/métodos , Linfonodos/patologia , Resultado do Tratamento
8.
Environ Res ; 239(Pt 2): 117381, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37832769

RESUMO

Freshwater habitats hold a unique role in the survival of all living organisms and supply water for drinking, irrigation, and life support activities. In recent decades, due to anthropogenic activities, deterioration in the water quality has been a long-lasting problem and challenge to the scientific fraternity. Although, these freshwater bodies have a bearable intrinsic capacity for pollution load however alarming increase in pollution limits the intrinsic capacities and requires additional technological interventions. The release of secondary pollutants from conventional interventions further needs revisiting the existing methodologies and asking for green interventions. Green interventions such as phycoremediation are natural, eco-friendly, economic, and energy-efficient alternatives and provide additional benefits such as nutrient recovery, biofuel production, and valuable secondary metabolites from polluted freshwater bodies. This systemic review in a nut-shell comprises the recent research insights on phycoremediation, technological implications, and influencing factors, and further discusses the associated mechanisms of metal ions biosorption by living and non-living algae, its advantages, and limitations. Besides, the article explores the possibility of future research prospects for applicability at a field scale that will help in the efficient utilization of resources, and improved ecological and health risks.


Assuntos
Poluentes Ambientais , Metais Pesados , Poluentes Químicos da Água , Plantas , Poluição Ambiental , Ecossistema , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/metabolismo
9.
Tech Coloproctol ; 27(9): 713-719, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37039927

RESUMO

The transanal approach to ileal pouch-anal anastomosis (Ta-IPAA) for ulcerative colitis was introduced in 2015 and has since been shown to be a safe and feasible technique, although the impact of this approach on patient function remains unclear. A systematic literature review was performed to identify studies exploring functional outcomes and quality of life after Ta-IPAA. Seven papers were identified, which all demonstrated satisfactory functional outcomes after Ta-IPAA as measured by tools such as Cleveland Global Quality of Life (CGQOL), Oresland Score (OS), Pouch Functional Score (PFS), and Inflammatory Bowel Disease Questionnaire (IBDQ). Many gaps in the literature were identified including paucity of follow-up data beyond the 1-year mark, lack of fertility and fecundity assessment as functional outcomes, and limited evaluation of objective physiologic anal sphincter function. The Ta-IPAA therefore shows promise for good functional results in the short-term, although further research will be required to evaluate the stability of function over time as the technique becomes increasingly integrated into modern surgical practice.


Assuntos
Colite Ulcerativa , Bolsas Cólicas , Proctocolectomia Restauradora , Humanos , Colite Ulcerativa/cirurgia , Qualidade de Vida , Resultado do Tratamento , Proctocolectomia Restauradora/efeitos adversos , Proctocolectomia Restauradora/métodos , Anastomose Cirúrgica , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia
10.
Tech Coloproctol ; 27(10): 787-797, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37150800

RESUMO

PURPOSE: Surgical treatment of complete rectal prolapse can be undertaken via an abdominal or a perineal approach. The present network meta-analysis aimed to compare the outcomes of different abdominal and perineal procedures for rectal prolapse in terms of recurrence, complications, and improvement in fecal incontinence (FI). METHODS: A PRISMA-compliant systematic review of PubMed, Scopus, and Web of Science was conducted. Randomized clinical trials comparing two or more procedures for the treatment of complete rectal prolapse were included. The risk of bias was assessed using the ROB-2 tool. The main outcomes were recurrence of full-thickness rectal prolapse, complications, operation time, and improvement in FI. RESULTS: Nine randomized controlled trials with 728 patients were included. The follow-up ranged between 12 and 47 months. Posterior mesh rectopexy had significantly lower odds of recurrence than did the Altemeier procedure (logOR, - 12.75; 95% credible intervals, - 40.91, - 1.75), Delorme procedure (- 13.10; - 41.26, - 2.09), resection rectopexy (- 11.98; - 41.36, - 0.19), sponge rectopexy (- 13.19; - 42.87, - 0.54), and sutured rectopexy (- 13.12; - 42.58, - 1.50), but similar odds to ventral mesh rectopexy (- 12.09; - 41.7, 0.03). Differences among the procedures in complications, operation time, and improvement in FI were not significant. CONCLUSIONS: Posterior mesh rectopexy ranked best with the lowest recurrence while perineal procedures ranked worst with the highest recurrence rates.


Assuntos
Procedimentos Cirúrgicos do Sistema Digestório , Incontinência Fecal , Laparoscopia , Prolapso Retal , Humanos , Prolapso Retal/cirurgia , Prolapso Retal/complicações , Metanálise em Rede , Laparoscopia/métodos , Reto/cirurgia , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Incontinência Fecal/cirurgia , Incontinência Fecal/complicações , Telas Cirúrgicas/efeitos adversos , Recidiva , Resultado do Tratamento , Ensaios Clínicos Controlados Aleatórios como Assunto
11.
J Environ Manage ; 326(Pt A): 116615, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36395641

RESUMO

Novel ZnS-Cu7S4 nanohybrid supported on chitosan matrix, as an ideal photocatalyst, was fabricated by the sonochemical method wherein high-resolution transmission electron microscopy (HRTEM) and X-ray powder diffraction (XRD) analysis confirmed the co-existence of both ZnS and Cu7S4; presence of vacancy sites in ZnS was verified by electron paramagnetic resonance (EPR) analysis and their introduction could promote two-photon excitation facilitated visible light response and charge transport/separation. The type II interface is formed in the ZnS-Cu7S4/Chitosan heterojunction owing to interstitial states that promote charge separation. The ZnS-Cu7S4/Chitosan was used for the photodegradation of a pharmaceutical pollutant, p-chlorophenol (PCP); over 98.8% of PCP photodegradation was achieved under visible-light irradiation where the ensued ·O2- and ·OH serve a key role in the photodegradation of PCP. In vitro cytotoxicity studies substantiated that the ZnS-Cu7S4/Chitosan is nontoxic to the ecosystem and human beings and endowed with promising photodegradation properties and accessibility via an environmentally friendly design, bodes well for its potential remediation applications.


Assuntos
Quitosana , Humanos , Fotólise , Ecossistema
12.
Phys Rev Lett ; 128(18): 185002, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35594117

RESUMO

Evolution of the hot spot plasma conditions was measured using high-resolution x-ray spectroscopy at the National Ignition Facility. The capsules were filled with DD gas with trace levels of Kr and had either a high-density-carbon (HDC) ablator or a tungsten (W)-doped HDC ablator. Time-resolved measurement of the Kr Heß spectra, absolutely calibrated by a simultaneous time-integrated measurement, allows inference of the electron density and temperature through observing Stark broadening and the relative intensities of dielectronic satellites. By matching the calculated hot spot emission using a collisional-radiative code to experimental observations, the hot spot size and areal density are determined. These advanced spectroscopy techniques further reveal the effect of W dopant in the ablator on the hot spot parameters for their improved implosion performance.

13.
Phys Rev Lett ; 129(27): 275001, 2022 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-36638294

RESUMO

We present measurements of ice-ablator mix at stagnation of inertially confined, cryogenically layered capsule implosions. An ice layer thickness scan with layers significantly thinner than used in ignition experiments enables us to investigate mix near the inner ablator interface. Our experiments reveal for the first time that the majority of atomically mixed ablator material is "dark" mix. It is seeded by the ice-ablator interface instability and located in the relatively cooler, denser region of the fuel assembly surrounding the fusion hot spot. The amount of dark mix is an important quantity as it is thought to affect both fusion fuel compression and burn propagation when it turns into hot mix as the burn wave propagates through the initially colder fuel region surrounding an igniting hot spot. We demonstrate a significant reduction in ice-ablator mix in the hot-spot boundary region when we increase the initial ice layer thickness.

14.
Phys Rev Lett ; 129(19): 195002, 2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36399755

RESUMO

The application of an external 26 Tesla axial magnetic field to a D_{2} gas-filled capsule indirectly driven on the National Ignition Facility is observed to increase the ion temperature by 40% and the neutron yield by a factor of 3.2 in a hot spot with areal density and temperature approaching what is required for fusion ignition [1]. The improvements are determined from energy spectral measurements of the 2.45 MeV neutrons from the D(d,n)^{3}He reaction, and the compressed central core B field is estimated to be ∼4.9 kT using the 14.1 MeV secondary neutrons from the D(T,n)^{4}He reactions. The experiments use a 30 kV pulsed-power system to deliver a ∼3 µs current pulse to a solenoidal coil wrapped around a novel high-electrical-resistivity AuTa_{4} hohlraum. Radiation magnetohydrodynamic simulations are consistent with the experiment.

15.
Anaesthesia ; 77(1): 82-95, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34545943

RESUMO

Haematoma after thyroid surgery can lead to airway obstruction and death. We therefore developed guidelines to improve the safety of peri-operative care of patients undergoing thyroid surgery. We conducted a systematic review to inform recommendations, with expert consensus used in the absence of high-quality evidence, and a Delphi study was used to ratify recommendations. We highlight the importance of multidisciplinary team management and make recommendations in key areas including: monitoring; recognition; post-thyroid surgery emergency box; management of suspected haematoma following thyroid surgery; cognitive aids; post-haematoma evacuation care; day-case thyroid surgery; training; consent and pre-operative communication; postoperative communication; and institutional policies. The guidelines support a multidisciplinary approach to the management of suspected haematoma following thyroid surgery through oxygenation and evaluation; haematoma evacuation; and tracheal intubation. They have been produced with materials to support implementation. While these guidelines are specific to thyroid surgery, the principles may apply to other forms of neck surgery. These guidelines and recommendations provided are the first in this area and it is hoped they will support multidisciplinary team working, improving care and outcomes for patients having thyroid surgery.


Assuntos
Hematoma/diagnóstico , Glândula Tireoide/cirurgia , Obstrução das Vias Respiratórias/etiologia , Obstrução das Vias Respiratórias/terapia , Cognição/fisiologia , Procedimentos Cirúrgicos Eletivos/efeitos adversos , Hematoma/etiologia , Hematoma/terapia , Humanos , Oxigenoterapia Hiperbárica , Intubação Intratraqueal
16.
Tech Coloproctol ; 26(9): 691-705, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35357610

RESUMO

BACKGROUND: Ileal pouch-anal anastomosis (IPAA) is commonly used to restore gastrointestinal continuity after surgical treatment of mucosal ulcerative colitis (MUC) and familial adenomatous polyposis (FAP). The aim of the present systematic review was to compare the outcomes of patients with MUC and patients with FAP who underwent IPAA. METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant systematic review was performed. PubMed, Scopus, and Web of Science were searched through December 2021. Cohort and randomized studies were eligible for inclusion if they directly compared patients with MUC and FAP who underwent IPAA. The main outcome measures were pouch failure, complications, and need for pouch excision or revision. ROBINS-I tool was used to assess the risk of bias across the studies. A random-effect meta-analysis was conducted. RESULTS: Twenty-three studies (9200 patients) were included in this meta-analysis. Seven thousand nine hundred fifty (86.4%) had MUC and 1250 (13.6%) had FAP. The median age of patients was 33.1 years. The male to female ratio was 1.4:1. MUC had higher odds of pouchitis (OR 3.9, 95% CI 2.8-5.4, p < 0.001), stricture (OR 1.82, 95% CI 1.25-2.65, p = 0.002), fistula (OR 1.74, 95% CI 1.18-2.54, p = 0.004), and total complications (OR 1.89, 95% CI 1.3-2.77, p < 0.001) as compared to FAP. Both groups had similar odds of pelvic sepsis, leakage, pouch failure, excision, revision, and fecal incontinence. CONCLUSIONS: Although patients with MUC undergoing IPAA may be at a higher risk of developing complications, particularly pouchitis, stricture, and fistula; the ultimate and functional outcome of the pouch is similar to patients with FAP. Pouch failure, excision and revision were similar in the two groups.


Assuntos
Polipose Adenomatosa do Colo , Colite Ulcerativa , Bolsas Cólicas , Pouchite , Proctocolectomia Restauradora , Polipose Adenomatosa do Colo/cirurgia , Adulto , Anastomose Cirúrgica/efeitos adversos , Colite Ulcerativa/cirurgia , Bolsas Cólicas/efeitos adversos , Constrição Patológica/etiologia , Feminino , Humanos , Masculino , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Pouchite/etiologia , Proctocolectomia Restauradora/efeitos adversos , Estudos Retrospectivos , Resultado do Tratamento
17.
J Environ Manage ; 319: 115674, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35868190

RESUMO

In this study, 3D C2S3 (CS) and 2D Bi2S3 (BS) modified NiCr2O4 nanocomposite (NCO-BS-CS NCs) was prepared by sonochemical assisted co-precipitation method for the enhanced photocatalytic activity. Here, NCO-BS-CS NCs showed band gap energy of 2.23 eV and the PL intensity of NCO-BS-CS NCs was lower than NCO, BS, and CS NPs. Thus, the results indicate the fabricated NCO-BS-CS NCs enhance the charge segregation and lower in recombination rate. NCO-BS-CS NCs showed enhanced photodegradation of methyl orange (MO) (95%) and congo red (CR) (99.7%) respectively. The total organic compound (TOC) analysis shows the complete mineralization of about 91 and 98% for MO and CR respectively. Furthermore, the Fukui function was used for the prediction of reactive sites in the photodegradation pathway of MO and CR by NCs. ECOSAR program was done to determine the toxicity of the intermediate and the results conclude that the degraded product shows nontoxic to the environmental organism (fish, daphnia, and algae). Thus, the fabricated NCO-BS-CS NCs can be used for the remediation of toxic organic pollutants from the waste water by photocatalytic degradation.


Assuntos
Poluentes Ambientais , Nanocompostos , Poluentes Químicos da Água , Animais , Catálise , Domínio Catalítico , Vermelho Congo/química , Poluentes Ambientais/análise , Luz , Nanocompostos/química , Nanocompostos/toxicidade , Esqueleto/química , Poluentes Químicos da Água/química
18.
J Environ Manage ; 317: 115321, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35751232

RESUMO

Sustainable wastewater treatment is crucial to remediate the water pollutants through the development of highly efficient, low-cost and separation free photocatalyst. The aim of this study is to construct a novel CoNiO2-BiFeO3-NiS ternary nanocomposite (NCs) for the efficient degradation of organic pollutants by utilising visible light. The NCs was characterized by various physiochemical techniques, including HR-TEM, SEM, XPS, FT-IR, ESR, EIS, PL, UV-visible DRS, and N2 adsorption and desorption analysis. The photocatalyst exhibits extraordinary degradation efficiency towards MO (99.8%) and RhB (97.8%). The intermediates were determined using GC-MS analysis and the degradation pathway was elucidated. The complete mineralization was further confirmed by TOC analysis. The CoNiO2-BiFeO3-NiS ternary NCs have shown excellent photostability, structural stability and reusability even after six cycles and it is confirmed by XRD and XPS analysis. The kinetic study reveals that the photodegradation of the dyes follows first order reaction. The influence of different pH, dye concentrations and NCs dosages were investigated. The intermediate toxicity was predicted by computational stimulation using ECOSAR software. The NCs shows promising potential for ecological safety which demonstrates its practical application in the treatment of waste water pollutants in large scale.


Assuntos
Nanocompostos , Poluentes Químicos da Água , Compostos Azo , Catálise , Corantes/química , Cinética , Luz , Nanocompostos/química , Rodaminas , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química
19.
J Environ Manage ; 308: 114614, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35121463

RESUMO

In this study, 3D BiOI nanoparticle (BOI NPs) modified MgCr2O4 nanoparticle (MCO NPs) was fabricated by simple sonochemical and coprecipitation method for the enhanced photocatalytic activity. The morphological structure of the MgCr2O4-BiOI nanocomposite (MCO-BOI NCs) was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (DRS), electron impedance spectroscopy (EIS) and photo luminescence (PL). The lower in the PL intensity and small arc in EIS for NCs shows the effective charge separation and lower in rate of recombination of charge carriers in NCs than the pure MCO and BOI NPs. The degradation efficiency of Rhodamine B (RhB) and malachite green (MG) by MCO-BOI NCs was found to be 99.5% and 98.2% receptivity. In addition, the photocatalytic degradation of RhB and MG was studied under various environmental parameters (different pH, varying the concentration of NCs and dyes) and response surface (RSM) plot was performed. The complete mineralization of RhB and MG by MCO-BOI NCs was determined by TOC. In addition, the photocatalytic degradation pathway was elucidated based on GC-MS results and Fukui function. In addition, the toxicity of intermediate formed during the degradation of RhB and MG was predicted by ECOSAR. The present work highlights the application of MCO-BOI NCs in environmental remediation for toxic pollutant removal.


Assuntos
Nanosferas , Catálise , Domínio Catalítico , Flores , Rodaminas , Corantes de Rosanilina
20.
J Environ Manage ; 306: 114396, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35026709

RESUMO

Novel photocatalyst CuO loaded ZnS nanoflower supported on carbon frame work PVA/Chitosan was synthesized by co-precipitation and ultrasonic assisted method. The co-existence of ZnS and CuO and its crystallinity in nanohybrid was verified by XRD, SAED and HR-TEM analysis. The availability of defects in ZnS was identified by EPR. FTIR and TGA verified the presence of PVA and Chitosan. Defects mediated ZnS-CuO/PVA/chitosan heterojunction promote synergistic charge separation with type II interface. Zn-vacancy facilitates two-photon excitation that improves visible-light harvesting. The photocatalytic activity of ZnS-CuO/PVA/Chitosan was 94.7% which is higher when compared to ZnS (40%) and CuO (60%). The photocatalytic mechanism was elucidated using scavenger test and both ·O2- and ·OH were found to play key role in tetracycline degradation. In addition, ZnS-CuO/PVA/Chitosan demonstrated efficient anti-microbial effect against the both gram strains on comparing with individual ZnS and CuO. Thus, the multifunctional ZnS-CuO/PVA/Chitosan is promising for the photocatalytic degradation of tetracycline and as an antimicrobial agent.


Assuntos
Quitosana , Antibacterianos/farmacologia , Catálise , Cobre , Luz , Sulfetos , Tetraciclina , Compostos de Zinco
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