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1.
Cureus ; 16(6): e61978, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38855498

RESUMO

Background Treatment of metastatic renal cell cancer (mRCC) has revolutionized with the introduction of anti-VEGF tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs). There is limited data in the literature on the outcomes of Indian patients treated with TKI. Here, we report the outcome of mRCC treated with first-line TKI in a resource-poor setting. Material and methods This is a single-center retrospective study of clear cell mRCC treated with first-line TKI from June 2012 to December 2022. Demographic characteristics and treatment details, including outcome data, were captured from electronic medical records. Patients who received at least one week of therapy were eligible for survival analysis. Results A total of 345 patients with metastatic clear cell histology were analyzed, with a median age of 61 years (range: 20-84 years). One hundred and eighty patients (52%) underwent nephrectomy before systemic therapy. The majority received pazopanib (257 patients, 75%), followed by sunitinib (36 patients, 10%) and cabozantinib (21 patients, 6%); 145 (45%) patients required dose interruption, and 143 (43%) required dose modification of TKI for adverse events. After a median follow-up of 44 months, the median progression-free survival (PFS) was 20.3 months (95% CI: 17.8-24.8), and the median overall survival (OS) was 22.7 months (95% CI: 18.8-28.3). In the poor-risk International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) group, no prior nephrectomy emerged as an independent poor-risk factor for both PFS and OS in multivariate analysis. Conclusion This is the largest single-center cohort of clear cell mRCC from Asia. Median PFS was 20.3 months with predominantly TKI monotherapy. In the poor-risk IMDC group, no prior nephrectomy emerged as an independent poor-risk factor for both PFS and OS.

2.
Phys Rev E ; 109(4-1): 044205, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38755835

RESUMO

This article confronts the formidable task of exploring chaos within hidden attractors in nonlinear three-dimensional autonomous systems, highlighting the lack of established analytical and numerical methodologies for such investigations. As the basin of attraction does not touch the unstable manifold, there are no straightforward numerical processes to detect those attractors and one has to implement special numerical and analytical strategies. In this article we present an alternative approach that allows us to predict the basin of attraction associated with hidden attractors, overcoming the existing limitations. The method discussed here is based on the Kosambi-Cartan-Chern theory which enables us to conduct a comprehensive theoretical analysis by means of evaluating geometric invariants and instability exponents, thereby delineating the regions encompassing chaotic and periodic zones. Our analytical predictions are thoroughly validated by numerical results.

3.
Cureus ; 16(4): e58804, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38784306

RESUMO

Objectives Vitiligo is a widespread cutaneous disorder. The present study aims to evaluate the epidemiologic profile of vitiligo and investigate its different clinical forms, disease activity, hereditary associations, triggering factors, and probable association with other diseases. Methods This prospective observational study was conducted over one year, from 2019 to 2020, and included 120 cases demonstrating definite clinical evidence of vitiligo. All selected patients underwent a detailed medical history interview. Specific enquiries were made regarding precipitating factors, clinical features of the disease, histories of other autoimmune diseases, and family histories. Thorough clinical, laboratory, and cutaneous examinations were performed on all patients. Descriptive statistical methods and diagrams were used to summarise the data. Results The age at presentation (31 patients, 25.8%) and the onset of the disease (32 patients, 26.6%) was predominantly in the second decade of life. The condition was usually progressive, with vitiligo vulgaris being the most prevalent type (56 cases, 46.7%). Disease onset (37 individuals, 30.8%) and the prevalence of lesions were higher in the lower leg. Body surface area involvement was ≤1% in 72 (60.0%) patients. Itching and trauma were the typical initiating factors. Leukotrichia in 38 (31.7%) cases, Koebner's phenomena in 23 (19.1%) cases, and a positive family history in 26 (21.7%) cases were observed. Thyroid dysfunction, hypertension, and various skin conditions are associated with the disease. Conclusion Vitiligo is more common in the young population. The condition is often progressive, with vitiligo vulgaris being the most common type. Itching and trauma are frequent initiating factors. Monitoring patients for associated diseases may be crucial for diagnosis and treatment outcomes.

4.
Ecancermedicalscience ; 18: 1667, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38439810

RESUMO

Background: Lorlatinib, an anaplastic lymphoma kinase (ALK)-inhibitor, is approved as frontline as well as subsequent line of therapy in ALK-rearranged advanced non-small cell lung cancer (NSCLC). There is limited literature about safety and efficacy of lorlatinib in Indian patients. Materials and methods: This was a retrospective multicentre study on patients with ALK-rearranged advanced NSCLC received lorlatinib as second line and beyond between May 2017 and December 2021. ALK was tested either by immunohistochemistry or fluorescent in-situ hybridisation. Clinicopathologic features, treatment details, toxicity and outcomes were analysed. Results: A total of 38 patients were enrolled with a median age of 54 years (range: 30-72) and male: female ratio of 20:18. Fifteen (44%) patients had brain metastases at baseline. Lorlatinib use was - second line in 11 (29%), third line in 21 (55%) and fourth line in 4 (11%) of patients, respectively. The best radiologic response to lorlatinib was - complete response in 9 (24%), partial response in 17 (46%), stable disease in 9 (24%) and progressive disease in 2 (5%) of patients, respectively. After a median follow-up of 76.6 months (95% CI: 68.9-100), the median progression-free survival (PFS) of lorlatinib was not reached (95% CI: 24.3-not reached) and median overall survival (OS) of the whole cohort was 93.1 months (95% CI: 62-not reached). Both median PFS (p = 0.48) and median OS (p = 0.74) was similar between second line and later line use of lorlatinib. Thirty-three (87%) patients experienced treatment-related toxicity and six (16%) patients required dose modification. Conclusion: Lorlatinib was highly efficacious in terms of overall response rate, median PFS and median OS in this small real-world cohort of advanced ALK+ve NSCLC with a manageable safety profile.

5.
Rice (N Y) ; 17(1): 20, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38526679

RESUMO

The aus (Oryza sativa L.) varietal group comprises of aus, boro, ashina and rayada seasonal and/or field ecotypes, and exhibits unique stress tolerance traits, making it valuable for rice breeding. Despite its importance, the agro-morphological diversity and genetic control of yield traits in aus rice remain poorly understood. To address this knowledge gap, we investigated the genetic structure of 181 aus accessions using 399,115 SNP markers and evaluated them for 11 morpho-agronomic traits. Through genome-wide association studies (GWAS), we aimed to identify key loci controlling yield and plant architectural traits.Our population genetic analysis unveiled six subpopulations with strong geographical patterns. Subpopulation-specific differences were observed in most phenotypic traits. Principal component analysis (PCA) of agronomic traits showed that principal component 1 (PC1) was primarily associated with panicle traits, plant height, and heading date, while PC2 and PC3 were linked to primary grain yield traits. GWAS using PC1 identified OsSAC1 on Chromosome 7 as a significant gene influencing multiple agronomic traits. PC2-based GWAS highlighted the importance of OsGLT1 and OsPUP4/ Big Grain 3 in determining grain yield. Haplotype analysis of these genes in the 3,000 Rice Genome Panel revealed distinct genetic variations in aus rice.In summary, this study offers valuable insights into the genetic structure and phenotypic diversity of aus rice accessions. We have identified significant loci associated with essential agronomic traits, with GLT1, PUP4, and SAC1 genes emerging as key players in yield determination.

6.
Eur J Cancer ; 200: 113560, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38306841

RESUMO

BACKGROUND: Neoadjuvant chemotherapy (NACT) with TPF (docetaxel, cisplatin, and 5FU) is one of the treatment options in very locally advanced oral cancer with a survival advantage over PF (cisplatin and 5FU). TP (docetaxel and cisplatin) has shown promising results with a lower rate of adverse events but has never been compared to TPF. METHODS: In this phase 3 randomized superiority study, adult patients with borderline resectable locally advanced oral cancers were randomized in a 1:1 fashion to either TP or TPF. After the administration of 2 cycles, patients were evaluated in a multidisciplinary clinic and further treatment was planned. The primary endpoint was overall survival (OS) and secondary endpoints were progression-free survival (PFS) and adverse events. RESULTS: 495 patients were randomized in this study, 248 patients in TP arm and 247 in TPF arm. The 5-year OS was 18.5% (95% CI 13.8-23.7) and 23.9% (95% CI 18.1-30.1) in TP and TPF arms, respectively (Hazard ratio 0.778; 95% CI 0.637-0.952; P = 0.015). Following NACT, 43.8% were deemed resectable, but 34.5% underwent surgery. The 5-year OS was 50.7% (95% CI 41.5-59.1) and 5% (95%CI 2.9-8.1), respectively, in the surgically resected versus unresected cohort post NACT (P < 0.0001). Grade 3 or above adverse events were seen in 97 (39.1%) and 179 (72.5%) patients in the TP and TPF arms, respectively (P < 0.0001). CONCLUSION: NACT with TPF has a survival benefit over TP in borderline resectable oral cancers, with an increase in toxicity which is manageable. Patients who undergo surgery achieve a relatively good, sustained survival.


Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Adulto , Humanos , Docetaxel/uso terapêutico , Platina/uso terapêutico , Cisplatino , Terapia Neoadjuvante , Fluoruracila , Taxoides/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias Bucais/tratamento farmacológico , Neoplasias Bucais/cirurgia , Quimioterapia de Indução/métodos , Neoplasias de Cabeça e Pescoço/tratamento farmacológico
7.
Microorganisms ; 11(11)2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-38004678

RESUMO

The guts of insect pests are typical habitats for microbial colonization and the presence of bacterial species inside the gut confers several potential advantages to the insects. These gut bacteria are located symbiotically inside the digestive tracts of insects and help in food digestion, phytotoxin breakdown, and pesticide detoxification. Different shapes and chemical assets of insect gastrointestinal tracts have a significant impact on the structure and makeup of the microbial population. The number of microbial communities inside the gastrointestinal system differs owing to the varying shape and chemical composition of digestive tracts. Due to their short generation times and rapid evolutionary rates, insect gut bacteria can develop numerous metabolic pathways and can adapt to diverse ecological niches. In addition, despite hindering insecticide management programs, they still have several biotechnological uses, including industrial, clinical, and environmental uses. This review discusses the prevalent bacterial species associated with insect guts, their mode of symbiotic interaction, their role in insecticide resistance, and various other biological significance, along with knowledge gaps and future perspectives. The practical consequences of the gut microbiome and its interaction with the insect host may lead to encountering the mechanisms behind the evolution of pesticide resistance in insects.

8.
Materials (Basel) ; 16(16)2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37629971

RESUMO

We present a scrutiny on the state of the art and applicability of predictive methods for additive manufacturing (AM) of metals, alloys, and compositionally complex metallic materials, to provide insights from the computational models for AM process optimization. Our work emphasizes the importance of manufacturing parameters on the thermal profiles evinced during processing, and the fundamental insights offered by the models used to simulate metal AM mechanisms. We discuss the methods and assumptions necessary for an educated tradeoff between the efficacy and accuracy of the computational approaches that incorporate multi-physics required to mimic the associated fluid flow phenomena as well as the resulting microstructures. Finally, the current challenges in the existing approaches are summarized and future scopes identified.

9.
Ecancermedicalscience ; 16: 1450, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36405937

RESUMO

Purpose: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have shown marked benefit in the treatment of hormone positive metastatic breast cancer (HR+ MBC). There are limited real-world studies with palbociclib and ribociclib. Here we report our experience with CDK4/6 inhibitors in these groups of patients. Material and methods: Patients with HR+ MBC who have received either palbociclib or ribociclib during the course of their treatment from January 2017 to January 2022 were included in the study. The baseline demographic features, treatment details and toxicity were recorded. Patients who received at least 1 month of therapy were included in the survival analysis. Results: A total of 144 patients received CDK4/6 inhibitors during the time period. The median age of the population was 53 (30-80) years. Ninety-eight (71.4%) patients presented with de novo metastatic disease. The most common site of metastasis was to the skeleton (74.2%). Most patients (75%) received palbociclib as their therapy. At a median follow-up of 20.2 months, the median progression free survival (PFS) of the whole population was 16.5 (95% confidence interval (95% CI): 11.6-25.5) months and the median overall survival (OS) was 29.7 (95% CI: 21.7-44.6) months. The presence of liver metastases, low progesterone receptor positivity (Allred score < 6) and prior systemic treatment were poor prognostic factors for both PFS and OS in multivariate analysis. Drug was discontinued for only 2.1% of the patient population. Conclusions: Use of CDK4/6 inhibitors has led to improvement in PFS and OS in patients with HR+ MBC and it is well tolerated. The presence of liver metastases and low progesterone receptor positivity (Allred score < 6) and prior treatment are poor prognostic factors.

10.
Int J Mol Sci ; 23(15)2022 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-35897719

RESUMO

TiO2 has aroused considerable attentions as a promising photocatalytic material for decades due to its superior material properties in several fields such as energy and environment. However, the main dilemmas are its wide bandgap (3-3.2 eV), that restricts the light absorption in limited light wavelength region, and the comparatively high charge carrier recombination rate of TiO2, is a hurdle for efficient photocatalytic CO2 conversion. To tackle these problems, lots of researches have been implemented relating to structural and material modification to improve their material, optical, and electrical properties for more efficient photocatalytic CO2 conversion. Recent studies illustrate that crystal facet engineering could broaden the performance of the photocatalysts. As same as for nanostructures which have advantages such as improved light absorption, high surface area, directional charge transport, and efficient charge separation. Moreover, strategies such as doping, junction formation, and hydrogenation have resulted in a promoted photocatalytic performance. Such strategies can markedly change the electronic structure that lies behind the enhancement of the solar spectrum harnessing. In this review, we summarize the works that have been carried out for the enhancement of photocatalytic CO2 conversion by material and structural modification of TiO2 and TiO2-based photocatalytic system. Moreover, we discuss several strategies for synthesis and design of TiO2 photocatalysts for efficient CO2 conversion by nanostructure, structure design of photocatalysts, and material modification.


Assuntos
Dióxido de Carbono , Nanoestruturas , Catálise , Nanoestruturas/química , Titânio/química
11.
Ecancermedicalscience ; 16: 1460, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36819802

RESUMO

Background: The data regarding the use of neoadjuvant chemotherapy in technically unresectable head and neck cancer (HNC) is limited and real-world studies are needed to look for the efficacy and toxicities of this approach. Patients and methods: This is a retrospective study conducted in the Medical Oncology department of our hospital. All technically unresectable HNC patients who underwent neoadjuvant chemotherapy between May 2018 and May 2020 were included in this analysis. Patients received three-drug regimen docetaxel, cisplatin and 5-fluorouracil (DCF) regimen, two-drug regimens included docetaxel + cisplatin, paclitaxel + carboplatin both weekly and 3-weekly. The resectability assessment was done clinically and radiologically after completing three neoadjuvant cycles. Overall survival was calculated from the first day of chemotherapy to the date of last follow-up or date of death. Results: A total of 119 patients received neoadjuvant chemotherapy during the specified time. Response assessment showed partial response in 41.9% of patients with three-drug regimens and 37.5% of patients with other regimens. Out of 119 patients, 56 (47%) patients were offered radical intent therapy. Resectability was achieved in 32.3% of three-drug regimen patients and 26.1% of other patients. Surgery was feasible in 33 (27.7%) patients, and postoperative radiotherapy and concurrent chemotherapy were done in 30 patients (25.2%), and surgery with only postoperative radiotherapy was done in 3 patients (2.5%). Radical chemoradiotherapy was done in 23 patients (19.3%). The estimated median survival for patients who could undergo surgery was 18 months [95% confidence interval (CI), 14.9-21.0], and nonsurgical patients were 9 months (95% CI, 7.3-10.6) (p = 0.0001). Conclusion: Our study shows that neoadjuvant chemotherapy in technically unresectable HNC patients can make the disease resectable in around one-third of the patients. The patients who could undergo surgery after neoadjuvant chemotherapy had significantly improved survival as compared to those who could not.

12.
Cureus ; 14(12): e32493, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36644062

RESUMO

The present case study showed the novel approach of Rucaparib and Bevacizumab as first-line maintenance therapy in germline BRCA 1 mutated advanced high-grade serous carcinoma of the ovary. A 56-year-old female with high-grade serous carcinoma of the ovary (ECOG PS1) was treated with carboplatin and paclitaxel in combination with Bevacizumab (CPB), followed by interval debulking surgery. Since the patient was germline BRCA 1 positive, after completion of adjuvant chemotherapy, she was kept on Rucaparib along with Bevacizumab. The patient achieved a complete response and has been leading a disease-free life for the past one year with maintenance therapy of Rucaparib + Bevacizumab, though the patient did experience a few adverse events, including one episode of grade 3 anaemia, occasional grade 3 asthenia, and grade 2 diarrhoea (CTCAE V-4) which was managed by gradual dose reduction of Rucaparib from 600 mg twice daily dose to 300mg twice daily dose. With dose alteration of rucaparib along with bevacizumab as maintenance, the patient continues to tolerate rucaparib and stay relapse-free from disease.

13.
Front Insect Sci ; 2: 1048299, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-38468791

RESUMO

The scale insects reduce plant photosynthetic ability by sucking sap from leaves and causing significant damage to the tea crop in most tea-producing countries. They suck the sap from stems and tea leaves, which not only prevents further growth but also reduces the nutritional quality of the leaves by promoting the growth of sooty molds. However, due to the widespread use of organosynthetic pesticides in recent decades, most insect pests have developed high levels of pesticide resistance, reducing the effectiveness of insecticide application. Bio-control agents are environmentally safe and produce long-term results while reducing the use of chemicals and other pesticides without disrupting the natural equilibrium. The review includes a list of coccidicides discovered on tea in major tea-growing countries as potential tea pests. The scope of future studies and the plans for better management of this serious sucking pest of the tea plant are also discussed in this review.

14.
JCO Glob Oncol ; 7: 1374-1379, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34506223

RESUMO

PURPOSE: The COVID-19 pandemic has imposed a unique challenge to oncology patients. Outcome data on COVID-19 in patients with cancer from the Indian subcontinent are scarce in the literature. We aimed to evaluate the outcome of patients with COVID-19 on active systemic anticancer therapy. MATERIALS AND METHODS: This is a retrospective study of patients with solid organ malignancies undergoing systemic therapy with a diagnosis of COVID-19 between March 2020 and February 2021. COVID-19 was diagnosed if a reverse transcriptase polymerase chain reaction assay from oropharyngeal or nasopharyngeal swab was positive for severe acute respiratory syndrome coronavirus 2. The objectives were to evaluate the outcome of COVID-19 and factors predicting the outcome. RESULTS: A total of 145 patients were included with a median age of 58 years (range, 20-81 years). Treatment was curative in 60 (42%) patients. Of all symptomatic cases (n = 88, 61%), 50 had mild, 27 had moderate and 19 had severe COVID-19-related symptoms as per WHO criteria. Fifty (34%) patients required hospitalization with a median duration of hospital stay of 12 days (range, 4-25 days); five patients required intensive care unit admission. The rest were treated with home isolation and did not require further hospitalization. Twenty-two (15%) patients died, and the risk of death was significantly associated with severity of symptoms (odds ratio, 91.3; 95% CI, 9.1 to 919.5, P = .0001) but not with any other clinical factors. Drug holiday was given to 63 (44%) patients with a median duration of 25 days (range, 7-88 days). The median duration to reverse transcriptase polymerase chain reaction-negative was 16 days (range, 7-62 days). CONCLUSION: COVD-19-related death rate was 15% among patients with solid organ malignancies. The severity of the symptoms was related to mortality. The majority of patients with mild symptoms were treated at home isolation.


Assuntos
COVID-19 , Neoplasias , Adulto , Idoso , Idoso de 80 Anos ou mais , Humanos , Índia/epidemiologia , Pessoa de Meia-Idade , Pandemias , Estudos Retrospectivos , SARS-CoV-2 , Adulto Jovem
15.
Appl Microbiol Biotechnol ; 105(19): 7187-7199, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34515843

RESUMO

The most consumed and economically important beverage plant, tea (Camellia sinensis), and its pests have coevolved so as to maintain the plant-insect interaction. In this review, findings of different research groups on pest responsive tolerance mechanisms that exist in tea manifested through the production of secondary metabolites and their inducers are presented. The phytochemicals of C. sinensis have been categorized into volatiles, nonvolatiles, enzymes, and phytohormones for convenience. Two types of pests, namely the piercing-sucking pests and chewing pests, are associated with tea. Both the insect groups can trigger the production of those metabolites and inducers through several primary and secondary biosynthetic pathways. These induced biomolecules can act as insect repellents and most of them are associated with lowering the nutrient quality of plant tissue and increasing the indigestibility in the pest's gut. Moreover, some of them also act as predator attractants of particular pests. The herbivore-induced plant volatiles secreted from tea plants during pest infestation were (E)-nerolidol, α-farnesene, (Z)-3-hexenol, (E)-4,8-dimethyl-1,3,7-nonatriene, indole, benzyl nitrile (BN), linalool, and ocimenes. The nonvolatiles like theaflavin and L-theanine were increased in response to the herbivore attack. Simultaneously, S-adenosyl-L-methionine synthase, caffeine synthase activities were affected, whereas flavonoid synthesis and wax formation were elevated. Defense responsive enzymes like peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, ascorbate peroxidase, and catalase are involved in pest prevention mechanisms. Phytohormones like jasmonic acid, salicylic acid, abscisic acid, and ethylene act as the modulator of the defense system. The objective of this review is to discuss the defensive roles of these metabolites and their inducers against pest infestation in tea with an aim to develop environmentally sustainable pesticides in the future.Key points• Herbivore-induced volatile signals and their effects on neighboring tea plant protection• Stereochemical conversion of volatiles, effects of nonvolatiles, expression of defense-responsive enzymes, and phytohormones due to pest attack• Improved understanding of metabolites for bio-sustainable pesticide development.


Assuntos
Camellia sinensis , Animais , Insetos , Chá
16.
Sci Rep ; 11(1): 13671, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34211096

RESUMO

Drought and phosphate availability are two major abiotic factors limiting productivity of rice in rainfed upland areas. There has been a constant need for new improved donor with tolerance to multiple abiotic stress conditions for rainfed rice breeding. In the present study, a set of 32 popular rice varieties and landraces were evaluated for drought and low-phosphorus (P) tolerance, and also characterized using grain yield under reproductive drought QTLs (DTY QTLs) and Pup1 linked/specific molecular markers. Twenty-seven genotypes were identified as tolerant to moderately tolerant to drought. The SSR markers linked to ten DTY QTLs classified the genotypes into two groups corresponding to aus and indica. The tolerant genotypes were distributed under both groups. Based on the core markers of Pup1 locus, complete tolerant haplotype was recorded in nine genotypes other than the tolerant check Dular. Nine more genotypes showed the incomplete tolerant haplotypes. The rice genotypes showed significantly high genetic variability for low-P tolerance in hydroponic study. A few genotypes revealed non-Pup1 type tolerance which needs further confirmation.


Assuntos
Oryza/genética , Aclimatação , Secas , Genes de Plantas , Variação Genética , Oryza/fisiologia , Fósforo/metabolismo , Melhoramento Vegetal , Locos de Características Quantitativas , Estresse Fisiológico
17.
Nanoscale Adv ; 3(2): 432-445, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-36131744

RESUMO

Understanding the electrical conduction properties of a single nanostructure is essential for gaining insight into the fundamental charge transport through 1D materials and also for exploring the collective behavior of an array of such nanostructures. TiO2 nanostructures, such as electrochemically grown nanotubes, have been widely studied in recent times for several applications. The electrolyte plays a vital role in deciding the morphology, which, in turn, governs the charge transport behavior. Here we present a comparative study of the charge transport through a single TiO2 nanotube grown by electrochemical anodization using ethylene glycol and dimethyl sulphoxide electrolytes. The individual nanotubes are assembled into nanodevices using photolithography without relying on complex and sophisticated process like electron beam lithography or focused ion beam deposition. The electric field dependent charge transport properties show Schottky emission at a lower field regime and Poole-Frenkel emission in the higher region. The temperature-dependent electrical conduction (110 K-410 K) is mediated by two thermal activation processes, attributed to shallow impurities in the low-temperature range (T < 230 K) and to the donors at deep intermediate levels at higher temperatures (T > 230 K). The activation energies for EG based nanotubes are found to be higher than those for DMSO nanotubes owing to the double wall morphology of the formed tubes. Also, the study of the electrical breakdown phenomena of these nanotubes reveals three distinct categories of collapse. 'Model A' type breakdown is characterized by a stepwise rise of the current up to the breakdown point and a fall to zero following a non-uniform step by step decrease, which is driven by crack formation near the electrode interface and its propagation. 'Model B' shows a transient rise and fall in current, leading to breakdown due to electromigration, whereas 'Model C' type breakdown observed in a bundle of nanotubes shows a mixed trend of 'Model A' and 'Model B'. The data and analysis provide insight into the current limit through an individual nanotube or bundle of nanotubes and will be useful for designing prototype nanodevices from titania nanostructures.

18.
Nanoscale Adv ; 4(1): 241-249, 2021 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36132944

RESUMO

Irradiation of materials by high energy (∼MeV) ions causes intense electronic excitations through inelastic transfer of energy that significantly modifies physicochemical properties. We report the effect of 100 MeV Ag ion irradiation and resultant localized (∼few nm) thermal spike on vertically oriented TiO2 nanorods (∼100 nm width) towards tailoring their structural and electronic properties. Rapid quenching of the thermal spike induced molten state within ∼0.5 picosecond results in a distortion in the crystalline structure that increases with increasing fluences (ions per cm2). Microstructural investigations reveal ion track formation along with a corrugated surface of the nanorods. The thermal spike simulation validates the experimental observation of the ion track dimension (∼10 nm diameter) and melting of the nanorods. The optical absorption study shows direct bandgap values of 3.11 eV (pristine) and 3.23 eV (5 × 1012 ions per cm2) and an indirect bandgap value of 3.10 eV for the highest fluence (5 × 1013 ions per cm2). First principles electronic structure calculations corroborate the direct-to-indirect transition that is attributed to the structural distortion at the highest fluence. This work presents a unique technique to selectively tune the properties of nanorods for versatile applications.

19.
Ecancermedicalscience ; 15: 1335, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35211204

RESUMO

PURPOSE: Malignant melanoma (MM) is rare in India. Indian data on demography and treatment outcome on advanced MM is very limited in the literature. MATERIALS & METHODS: This is a retrospective study of advanced MM treated between January 2013 and December 2020. We evaluated the clinicopathologic features, mutational profiles, survival outcome and prognostic factors in advanced MM patients. RESULTS: Out of a total 460 patients, 185 (42%) had metastatic disease at presentation and were enrolled in this study with a median age of 63 years (range: 28-93) and male:female ratio of 94:91. The mucosal primary was predominant (n = 110, 59%) than cutaneous primary (38%) and anorectum was the most common site (n = 84, 45%). Tumour mutational analysis was performed in 65 (35%) patients. BRAF mutations were detected in 12 patients and KIT mutations in 7 patients. Thirteen patients didn't have any mutations and 22 patients had mutations other than KIT & BRAF. Only 59 (32%) patients took any systemic treatment - immune checkpoint inhibitors (ICIs) in 17, temozolomide in 18 and paclitaxel/carboplatin in 18, tyrosine kinase inhibitors in 6 patients. After a median follow-up of 26 months (95% confidence interval (CI): 11.6-not reached), median progression-free survival (PFS) was 7.1 months (95% CI: 4.4-9.1) and median overall survival was 14.8 months (95% CI: 7.7-18.2 months). The use of ICI emerged as an only significant good prognostic factor (p ≤ 0.001) for PFS, on multivariate analysis. CONCLUSION: Mucosal origin was more common than cutaneous primary with anorectum being the most common site. BRAF mutation was less as compared to published literature. Very few patients received systemic therapy and the use of ICI showed superior PFS.

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