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1.
Small ; 20(14): e2306756, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38126960

RESUMEN

For an uninterrupted self-powered network, the requirement of miniaturized energy storage device is of utmost importance. This study explores the potential utilization of phosphorus-doped nickel oxide (P-NiO) to design highly efficient durable micro-supercapacitors. The introduction of P as a dopant serves to enhance the electrical conductivity of bare NiO, leading to 11-fold augmentation in volumetric capacitance to 841.92 Fcm-3 followed by significant enhancement of energy and power density from 6.71 to 42.096 mWhcm-3 and 0.47 to 1.046 Wcm-3, respectively. Theoretical calculations used to determine the adsorption energy of OH- ions, revealing higher in case of bare NiO (1.52 eV) as compared to phosphorus-doped NiO (0.64 eV) leading to high electrochemical energy storage performance. The as-designed micro-supercapacitor (MSC) device demonstrates a facile integration with the photovoltaic system for renewable energy storage and smooth transfer to external loads for enlightening the blue LED for ≈1 min. The choice of P-NiO/Ni not only contributes to cost reduction but also ensures minimal lattice mismatch at the interface facilitating high durability up to 15 K cycles along with capacitive retention of ≈100% and coulombic efficiency of 93%. Thus, the heterostructure unveils the possibilities of exploring miniaturized energy storage devices for portable electronics.

2.
Langmuir ; 39(1): 320-333, 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36525568

RESUMEN

Mechanical and solar to electrical energy conversion using piezo- and ferroelectric and photovoltaic effects may be a practical answer to the rising energy demand. In this quest, piezoelectric polymer poly(vinylidene fluoride-hexafluoroproylene) (P(VDF-HFP)) has gained interest due to its superior piezo- and ferroelectricity. In photovoltaic applications, inorganic halide perovskite (IHP) of CsPbI3 is considered a prime model compound. However, its application is limited because of the photoactive perovskite phase instability at ambient conditions. Here, we report the in situ synthesis of the stable perovskite γ-CsPbI3 through an electrospinning process at room temperature, encapsulated within a ferroelectric copolymer poly(vinylidene fluoride-hexafluoroproylene) (P(VDF-HFP)) as a composite nanofiber. Computational calculation using density functional theory (DFT) reveals that tensile strain plays a critical role in the dynamical stabilization of γ-CsPbI3. This tensile strain is triggered by the electrospinning process, which aids in the formation and growth of γ-CsPbI3. In the CsPbI3-P(VDF-HFP) composite nanofiber, γ-CsPbI3 nucleates the polar ß-crystalline phase in P(VDF-HFP), which results in the intrinsic piezo- and ferroelectric characteristics. The γ-CsPbI3 aids in preferable molecular dipole orientation, resulting in improved nanoscale piezo- and ferroelectric properties. The composite nanofiber features a higher piezoelectric d33 magnitude (∼30 pm/V) and lower decay constant for polarized domains (τcomposite ≈ 17). The composite was utilized as a piezoelectric nanogenerator to demonstrate human physiological motion monitoring in self-power mode. The relevant pressure sensitivities of 81 and 40 mV/kPa for the low-pressure (<0.6 kPa) and high-pressure (>0.6 to 12 kPa) ranges, respectively, promise its suitability in the health care sector.

3.
Ann Hepatol ; 28(3): 101088, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36933885

RESUMEN

INTRODUCTION AND OBJECTIVES: Psychosocial stressors related to the coronavirus-19 (COVID-19) pandemic increased alcohol consumption. The effect on patients with alcohol-related liver diseases remains unclear. MATERIALS AND METHODS: Hospitalizations at a tertiary care center due to alcohol-related liver disease from March 1 through August 31 in 2019 (pre-pandemic cohort) and 2020 (pandemic cohort) were reviewed retrospectively. Differences in patient demographics, disease features, and outcomes were estimated in patients with alcoholic hepatitis utilizing T-tests, Mann-Whitney tests, Chi-square and Fisher Exact Tests and Anova models and logistic regression models in patients with alcoholic cirrhosis. RESULTS: 146 patients with alcoholic hepatitis and 305 patients with alcoholic cirrhosis were admitted during the pandemic compared to 75 and 396 in the pre-pandemic cohort. Despite similar median Maddrey Scores (41.20 vs. 37.45, p=0.57), patients were 25% less likely to receive steroids during the pandemic. Patients with alcoholic hepatitis admitted during the pandemic were more likely to have hepatic encephalopathy (0.13; 95% CI:0.01, 0.25), variceal hemorrhage (0.14; 95% CI:0.04, 0.25), require oxygen (0.11; 95% CI:0.01, 0.21), vasopressors (OR:3.49; 95% CI:1.27, 12.01) and hemodialysis (OR:3.70; 95% CI:1.22, 15.13). On average, patients with alcoholic cirrhosis had MELD-Na scores 3.77 points higher (95% CI:1.05, 13.46) as compared to the pre-pandemic and had higher odds of experiencing hepatic encephalopathy (OR:1.34; 95% CI:1.04, 1.73), spontaneous bacterial peritonitis (OR:1.88; 95% CI:1.03, 3.43), ascites (OR:1.40, 95% CI:1.10, 1.79), vasopressors (OR:1.68, 95% CI:1.14, 2.46) or inpatient mortality (OR:2.00, 95% CI:1.33, 2.99) than the pre-pandemic. CONCLUSIONS: Patients with alcohol-related liver disease experienced worse outcomes during the pandemic.


Asunto(s)
COVID-19 , Várices Esofágicas y Gástricas , Encefalopatía Hepática , Hepatitis Alcohólica , Humanos , Cirrosis Hepática Alcohólica/epidemiología , Cirrosis Hepática Alcohólica/terapia , Encefalopatía Hepática/epidemiología , Pandemias , Hepatitis Alcohólica/diagnóstico , Hepatitis Alcohólica/epidemiología , Estudios Retrospectivos , Hemorragia Gastrointestinal , Pronóstico , COVID-19/epidemiología , Cirrosis Hepática/diagnóstico , Cirrosis Hepática/epidemiología
4.
Biochem J ; 478(16): 3079-3098, 2021 08 27.
Artículo en Inglés | MEDLINE | ID: mdl-34350952

RESUMEN

DevR/DosR response regulator is believed to participate in virulence, dormancy adaptation and antibiotic tolerance mechanisms of Mycobacterium tuberculosis by regulating the expression of the dormancy regulon. We have previously shown that the interaction of DevR with RNA polymerase is essential for the expression of DevR-regulated genes. Here, we developed a M. tuberculosis-specific in vivo transcription system to enrich our understanding of DevR-RNA polymerase interaction. This in vivo assay involves co-transforming E. coli with two plasmids that express α, ß, ß' and σA subunits of M. tuberculosis RNA polymerase and a third plasmid that harbors a DevR expression cassette and a GFP reporter gene under the DevR-regulated fdxA promoter. We show that DevR-dependent transcription is sponsored exclusively by M. tuberculosis RNA polymerase and regulated by α and σA subunits of M. tuberculosis RNA polymerase. Using this E. coli triple plasmid system to express mutant variants of M. tuberculosis RNA polymerase, we identified E280 residue in C-terminal domain of α and K513 and R515 residues of σA to participate in DevR-dependent transcription. In silico modeling of a ternary complex of DevR, σA domain 4 and fdxA promoter suggest an interaction of Q505, R515 and K513 residues of σA with E178 and D172 residues of DevR and E471 of σA, respectively. These findings provide us with new insights into the interactions between DevR and RNA polymerase of M. tuberculosis which can be targeted for intercepting DevR function. Finally, we demonstrate the utility of this system for screening of anti-DevR compounds.


Asunto(s)
Proteínas Bacterianas/genética , Proteínas de Unión al ADN/genética , Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica , Mycobacterium tuberculosis/genética , Regiones Promotoras Genéticas/genética , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Secuencia de Bases , ADN/química , ADN/genética , ADN/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/metabolismo , Modelos Moleculares , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/patogenicidad , Conformación de Ácido Nucleico , Plásmidos/genética , Unión Proteica , Dominios Proteicos , Homología de Secuencia de Aminoácido , Tuberculosis/microbiología , Virulencia/genética
5.
Int J Equity Health ; 19(1): 176, 2020 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-33028321

RESUMEN

An amendment to this paper has been published and can be accessed via the original article.

6.
Int J Equity Health ; 19(1): 138, 2020 08 13.
Artículo en Inglés | MEDLINE | ID: mdl-32792002

RESUMEN

BACKGROUND: India is strongly committed to reducing the burden of child malnutrition, which has remained a persistent concern. Findings from recent surveys indicate co-existence of child undernutrition, micronutrient deficiency and overweight/obesity, i.e. the triple burden of malnutrition among children below 5 years. While considerable efforts are being made to address this challenge, and several composite indices are being explored to inform policy actions, the methodology used for creating such indices, i.e., linear averaging, has its limitations. Briefly put, it could mask the uneven improvement across different indicators by discounting the 'lagging' indicators, and hence not incentivising a balanced improvement. Signifying negative implications on policy discourse for improved nutrition. To address this gap, we attempt to develop a composite index for estimating the triple burden of malnutrition in India, using a more sensitive measure, MANUSH. METHODOLOGY: Data from publicly available nation-wide surveys - National Family Health Survey (NFHS) and Comprehensive National Nutrition Survey (CNNS), was used for this study. First, we addressed the robustness of MANUSH method of composite indexing over conventional aggregation methods. Second, using MANUSH scores, we assessed the triple burden of malnutrition at the subnational level over different periods NHFS- 3(2005-06), NFHS-4 (2015-16) and CNNS (2106-18). Using mapping and spatial analysis tools, we assessed neighbourhood dependency and formation of clusters, within and across states. RESULT: MANUSH method scores over other aggregation measures that use linear aggregation or geometric mean. It does so by fulfilling additional conditions of Shortfall and Hiatus Sensitivity, implicitly penalising cases where the improvement in worst-off dimension is lesser than the improvement in best-off dimension, or where, even with an overall improvement in the composite index, the gap between different dimensions does not reduce. MANUSH scores helped in revealing the gaps in the improvement of nutrition outcomes among different indicators and, the rising inequalities within and across states and districts in India. Significant clusters (p < 0.05) of high burden and low burden districts were found, revealing geographical heterogeneities and sharp regional disparities. A MANUSH based index is useful in context-specific planning and prioritising different interventions, an approach advocated by the newly launched National Nutrition Mission in India. CONCLUSION: MANUSH based index emphasises balanced development in nutritional outcomes and is hence relevant for diverse and unevenly developing economy like India.


Asunto(s)
Trastornos de la Nutrición del Niño/epidemiología , Disparidades en el Estado de Salud , Indicadores de Salud , Desnutrición/epidemiología , Estado Nutricional , Obesidad/epidemiología , Características de la Residencia , Trastornos de la Nutrición del Niño/prevención & control , Preescolar , Comorbilidad , Femenino , Humanos , India/epidemiología , Lactante , Masculino , Desnutrición/prevención & control , Micronutrientes/deficiencia , Encuestas Nutricionales , Obesidad/prevención & control , Sobrepeso/epidemiología , Sobrepeso/prevención & control , Políticas , Factores de Riesgo , Factores Socioeconómicos , Análisis Espacial
7.
Altern Lab Anim ; 48(2): 85-91, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32429688

RESUMEN

The quality of animal experiments in terms of appropriate reporting is a concern, particularly with regard to their validity and the recording of the measures taken to reduce various types of bias. A systematic survey of 1371 and 236 publications from India and Sri Lanka, respectively, which were published between 1905 and 2017 and indexed in NCBI-PubMed, Cinhal, MEDLINE and Scopus, was carried out. The level of detail in the descriptions of animals used and the measures taken to reduce bias were analysed in each article. Selected parameters from the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines, such as age, weight, sex, sample size calculation, blinding and randomisation were considered. The findings revealed poor reporting standards in animal experiments carried out in India and Sri Lanka, confirming the limited impact of the ARRIVE guidelines. These findings emphasise the urgent need for improvements in the peer review process, both prior to a study being set up and in the post-study reporting phase, and for more stringent adherence to the ARRIVE guidelines in the reporting of animal experiments.


Asunto(s)
Experimentación Animal , Animales , India , Sri Lanka , Encuestas y Cuestionarios
8.
J Cell Biochem ; 120(8): 13867-13880, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-30938873

RESUMEN

Mutations in the human SBDS gene is the most common cause of Shwachman-Diamond syndrome (SDS). The SBDS protein participates in ribosome biogenesis; however, effects beyond reduced translation efficiency are thought to be involved in SDS progression. Impaired mitochondrial function has been reported for cells lacking either SBDS or Sdo1p, the Saccharomyces cerevisiae SBDS ortholog. To better understand how the loss of SBDS/Sdo1p leads to mitochondria damage, we utilized the S. cerevisiae model of SDS. Yeast deleted for SDO1 show increased oxidative damage to mitochondrial proteins and a marked decrease in protein levels and activity of mitochondrial superoxide dismutase 2 (Sod2p), a key enzyme involved in defense against oxidants. Immature forms of Sod2p are observed in sdo1∆ cells suggesting a defect in proteolysis of the presequence. Yeast deleted for CYM1, encoding a presequence protease, display a similar reduction in Sod2p activity as sdo1∆ cells, as well as elevated oxidative damage, to mitochondrial proteins. Sod2p protein levels and activity are largely restored in a por1∆ sdo1∆ strain, lacking the major mitochondrial voltage-dependent anion channel. Together these results indicate that mitochondrial insufficiency in sdo1∆ cells may be linked to the accumulation of immature presequence containing proteins and this effect is a consequence, at least in part, from loss of counter-regulation of Por1p by Sdo1p.


Asunto(s)
Mitocondrias/metabolismo , Modelos Biológicos , Saccharomyces cerevisiae/enzimología , Síndrome de Shwachman-Diamond/enzimología , Superóxido Dismutasa/metabolismo , Estrés Oxidativo , Biosíntesis de Proteínas
9.
Pediatr Blood Cancer ; 65(3)2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29134740

RESUMEN

BACKGROUND: Studies on mitochondrial DNA copy number reveal an increase or decrease in copy number that appears to be cancer specific, but data on acute lymphoblastic leukemia have been inconsistent regarding the significance of changes in mitochondrial DNA copies. The purpose of this pilot study was to analyze mitochondrial DNA copy number and mitochondrial DNA integrity. PROCEDURE: Copy number and mitochondrial deletion ratios were estimated in the bone marrow of 51 patients and peripheral blood of 30 healthy controls using quantitative real-time PCR. The copy number values were correlated with prognostic markers in patients. RESULTS: Significantly increased mitochondrial DNA copy number (P-value < 0.0001) and increased mitochondrial deletion ratios (P-value = 0.0018) were observed in patients compared with controls. The copy numbers were significantly decreased in patients after chemotherapy (P-value = 0.0232). Patients with higher copy numbers exhibited significantly inferior survival than patients with lower copy numbers (for event-free survival, P-value = 0.04 and overall survival, P-value = 0.1175). CONCLUSIONS: Significant decreases in mitochondrial DNA copy number with therapy indicates that copy number could be evaluated as a potential marker for therapeutic efficacy and a higher mitochondrial DNA copy number could be a poor prognostic marker.


Asunto(s)
Biomarcadores de Tumor/genética , Variaciones en el Número de Copia de ADN , ADN Mitocondrial/análisis , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Adolescente , Antineoplásicos/uso terapéutico , Niño , Preescolar , Variaciones en el Número de Copia de ADN/efectos de los fármacos , ADN Mitocondrial/genética , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Proyectos Piloto , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Pronóstico
10.
Cell Immunol ; 313: 25-31, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28063598

RESUMEN

Following burn injury, a key factor for patients susceptible to opportunistic infections is immune suppression. Butyrate levels are important in maintaining a functional immune system and these levels can be altered after injury. The acid sphingomyelinase (Asm) lipid signaling system has been implicated in a T cell actions with some evidence of being influenced by butyrate. Here, we hypothesized that burn-injury changes in butyrate levels would mediate Asm activity and, consequently, T cell homeostasis. We demonstrate that burn injury temporally decreases butyrate levels. We further determined that T cell Asm activity is increased by butyrate and decreased after burn injury. We additionally observed decreased T cell numbers in Asm-deficient, burn-injured, and microbiota-depleted mice. Finally, we demonstrate that butyrate reduced T cell death in an Asm-dependent manner. These data suggest that restoration of butyrate after burn injury may ameliorate the T cell lost observed in burn-injured patients by Asm regulation.


Asunto(s)
Quemaduras/inmunología , Esfingomielina Fosfodiesterasa/metabolismo , Linfocitos T/inmunología , Animales , Apoptosis , Butiratos/metabolismo , Células Cultivadas , Modelos Animales de Enfermedad , Técnicas de Inactivación de Genes , Homeostasis , Humanos , Masculino , Ratones , Ratones Endogámicos , Transducción de Señal , Esfingomielina Fosfodiesterasa/genética
13.
J Assoc Physicians India ; 62(6): 538-41, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25856926

RESUMEN

Hereditary amyloid polyneuropathies are rare, heterogeneous group of autosomal dominant disorders and deserve special attention because of its rare presentation, multisystem involvement and significant therapeutic implications if diagnosed early. We report a male patient of hereditary amyloid polyneuropathy from North West India with peripheral nerve, autonomic nervous system, vitreous and cardiac involvement.


Asunto(s)
Neuropatías Amiloides/genética , Neuropatías Amiloides/patología , Imagen por Resonancia Magnética , Adulto , Humanos , India , Masculino , Linaje , Fenotipo
14.
Head Neck Pathol ; 18(1): 18, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38489075

RESUMEN

Only limited cases have been reported about the clear cell variant of squamous cell carcinoma occurring in the oral cavity. The present study regards the case showing the histopathological features of both the clear cell and acantholytic variants of oral squamous cell carcinoma. A review of the literature has been done to understand the pathogenesis of those changes. Also, a hypothesis has been given that the clear cell changes could be the consequences of the cascades of the acantholytic process and not a separate entity. Therefore, more research is required to confirm this hypothesis and understand the prognosis of the lesion.


Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Humanos , Carcinoma de Células Escamosas/patología , Neoplasias de la Boca/patología , Carcinoma de Células Escamosas de Cabeza y Cuello , Acantólisis/patología
15.
Indian J Otolaryngol Head Neck Surg ; 76(3): 2257-2272, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38883453

RESUMEN

Owing to high global prevalence, incidence and associated mortality, cancer of head and neck particularly oral cancer remains a cardinal domain for research and trials. Immune-modulatory therapies that employ patients own immune system for therapeutic benefits in oral cancer seems promising. The aim of this review is to gauge the potential of immunotherapy as fourth domain of Oral cancer therapeutics. Articles were searched using suitable search terms in MEDLINE and Google Scholar database to include clinical trials, meta-analyses, and research in humans/animals/cell lines published in peer reviewed journals. A total of 97 articles were included in this review. Literature has several studies and trials where different types of immunotherapies has been attempted but it is crucial to identify precise biomarkers of genome based targeted agents and to find parameters to select patients who might benefit from immunotherapy. Also further research is required to estimate predictive value of tumor mutational burden and mutational signatures so as to aid in personalized prediction of oral cancer therapeutic response.

16.
Indian J Otolaryngol Head Neck Surg ; 76(1): 1178-1182, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38440495

RESUMEN

Brown tumor represents a terminal stage of bone remodeling process due to an imbalance between osteoclastic and osteoblastic activity. It represents a reparative cellular process, rather than a neoplastic process mostly associated with primary or secondary hyperparathyroidism. Although parathyroidectomy is the first treatment of choice for brown tumors, several cases don't resolve even after normalization of parathyroid hormone levels which leads to surgical intervention. Therefore, to avoid multiple bone surgeries in the same patient, it is crucial to have a conservative approach like targeted therapy which could block certain molecules involved in bone resorption. In this string, we have recognized and quantified three molecules namely sclerostin, MCP-1 and CD73 in brown tumors and correlated their expression with bone resorption pathogenesis and potential therapeutic approach.

17.
Indian J Otolaryngol Head Neck Surg ; 76(1): 1402-1409, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38440613

RESUMEN

The objective of this study was to review the clinical, radiologic, and histologic aspects of cases of dentigerous cysts metamorphosing into different entities along with comments on the molecular factors involved in the process. A series comprising 8 cases of dentigerous cysts was performed retrospectively along with a comprehensive literature review. Two cases of dentigerous cyst converting into mucous metaplasia were included, out of which one case was transformed into ameloblastoma after a year. The other two cases were reported as acanthomatous and unicystic ameloblastoma, whereas four transitioned to AOT. The complete review of cases and literature with molecular profiling concluded that the lining of dentigerous cysts has the potential for transforming into benign odontogenic tumors. Therefore, a careful clinical and histopathological examination is crucial for the correct diagnosis. Also, a thorough molecular understanding of the cystic lining is required.

18.
Head Neck Pathol ; 18(1): 21, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38502412

RESUMEN

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a commonly occurring malignancy with complex genetic alterations contributing to its development. The H-Ras, a proto-oncogene, becomes an oncogene when mutated and has been implicated in various cancers. This systematic review aims to research to what extent H-Ras expression and mutation contribute to the development and progression of OSCC, and how does this molecular alteration impacts the clinical characteristics and prognosis in patients with OSCC. METHODS: A thorough electronic scientific literature search was carried out in PUBMED, SCOPUS, and GOOGLE SCHOLAR databases from 2007 to 2021. The search strategy yielded 120 articles. Following aggregation and filtering all results through our inclusion and exclusion criteria total 9 articles were included in our literature review. It has also been registered with PROSPERO (CRD42023485202). RESULTS: It was found that mutations in the Ras gene commonly reported in hotspots at codons 12, 13, and 61 resulting in the activation of downstream signaling pathways causing abnormal and uncontrolled cell growth. This systematic review has shown an increased prevalence of H-Ras mutation in well-differentiated OSCC and also the prevalence of H-Ras mutation in individuals engaging in multiple risk behaviors, particularly chewing tobacco, demonstrated a significant association with a higher prevalence of H-Ras positivity. CONCLUSION: This review sheds light on the prevalence of H-Ras mutations, their association with clinical characteristics, and their potential implications for OSCC prognosis. It also enhances our comprehension of the molecular mechanisms that underlie OSCC and paves the way for further research into targeted treatments based on H-Ras alterations.


Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Humanos , Carcinoma de Células Escamosas/patología , Neoplasias de la Boca/patología , Mutación , Carcinoma de Células Escamosas de Cabeza y Cuello/genética
19.
ACS Appl Mater Interfaces ; 16(20): 26899-26914, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38741334

RESUMEN

The extreme sensitivity of 2D-layered materials to environmental adsorbates, which is typically seen as a challenge, is harnessed in this study to fine-tune the material properties. This work investigates the impact of environmental adsorbates on electrical properties by studying metal-semiconductor-metal (MSM) devices fabricated on CVD-synthesized SnSe flakes. The freshly prepared devices exhibit positive photoconductivity (PPC), whereas they gradually develop negative photoconductivity (NPC) after being exposed to an ambient environment for ∼1 day. While the photodetectors based on positive photoconductivity exhibit a responsivity and detectivity of 6.1 A/W and 5.06 × 108 Jones, the same for the negative photoconductivity-based photodetector reaches up to 36.3 A/W and 1.49 × 109 Jones, respectively. In addition, the noise-equivalent power of the NPC photodetector decreases by 300 times as compared to the PPC device, which implies a prominent detection capability of the NPC device against weak photo signals. To substantiate the hypothesis that negative photoconductivity stems from the photodesorption of water and oxygen molecules on the dangling bonds of SnSe flakes, the flakes are etched along the most active planes (010) with a focused laser beam in an inert environment, which enhances responsivity by 43%, supporting negative photoconductivity linked to photodesorption. Furthermore, the humidity-dependent dark current variation of the NPC photodetectors is used to design a humidity sensor for human respiration monitoring with faster response and recovery times of 0.72 and 0.68 s, respectively. These findings open up the possibility of tuning the photoelectrical response of layered materials in a facile manner to develop future sensors and optoelectronic multifunctional devices.

20.
Med Image Anal ; 92: 103047, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38157647

RESUMEN

Nuclear detection, segmentation and morphometric profiling are essential in helping us further understand the relationship between histology and patient outcome. To drive innovation in this area, we setup a community-wide challenge using the largest available dataset of its kind to assess nuclear segmentation and cellular composition. Our challenge, named CoNIC, stimulated the development of reproducible algorithms for cellular recognition with real-time result inspection on public leaderboards. We conducted an extensive post-challenge analysis based on the top-performing models using 1,658 whole-slide images of colon tissue. With around 700 million detected nuclei per model, associated features were used for dysplasia grading and survival analysis, where we demonstrated that the challenge's improvement over the previous state-of-the-art led to significant boosts in downstream performance. Our findings also suggest that eosinophils and neutrophils play an important role in the tumour microevironment. We release challenge models and WSI-level results to foster the development of further methods for biomarker discovery.


Asunto(s)
Algoritmos , Procesamiento de Imagen Asistido por Computador , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Núcleo Celular/patología , Técnicas Histológicas/métodos
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