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1.
Small ; : e2401891, 2024 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-39004881

RESUMEN

Various polytypes of van der Waals (vdW) materials can be formed by sulfur and tin, which exhibit distinctive and complementary electronic properties. Hence, these materials are attractive candidates for the design of multifunctional devices. This work demonstrates direct selective growth of tin sulfides by laser irradiation. A 532 nm continuous wave laser is used to synthesize centimeter-scale tin sulfide tracks from single source precursor tin(II) o-ethylxanthate under ambient conditions. Modulation of laser irradiation conditions enables tuning of the dominant phase of tin sulfide as well as SnS2/SnS heterostructures formation. An in-depth investigation of the morphological, structural, and compositional characteristics of the laser-synthesized tin sulfide microstructures is reported. Furthermore, laser-synthesized tin sulfides photodetectors show broad spectral response with relatively high photoresponsivity up to 4 AW-1 and fast switching time (τ rise = 1.8 ms and τ fall = 16 ms). This approach is versatile and can be exploited in various fields such as energy conversion and storage, catalysis, chemical sensors, and optoelectronics.

2.
Acad Radiol ; 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38693026

RESUMEN

RATIONALE AND OBJECTIVES: To develop and validate a predictive model for osteoporosis and osteopenia prediction by fusing deep transfer learning (DTL) features and classical radiomics features based on single-source dual-energy computed tomography (CT) virtual monochromatic imaging. METHODS: A total of 606 lumbar vertebrae with dual-energy CT imaging and quantitative CT (QCT) evaluation were included in the retrospective study and randomly divided into the training (n = 424) and validation (n = 182) cohorts. Radiomics features and DTL features were extracted from 70-keV monochromatic CT images, followed by feature selection and model construction, radiomics and DTL features models were established. Then, we integrated the selected two types of features into a features fusion model. We developed a two-level classifier for the hierarchical pairwise classification of each vertebra. All the vertebrae were first classified into osteoporosis and non-osteoporosis groups, then non-osteoporosis group was classified into osteopenia and normal groups. QCT was used as reference. The predictive performance and clinical usefulness of three models were evaluated and compared. RESULTS: The area under the curve (AUC) of the features fusion, radiomics and DTL models for the classification between osteoporosis and non-osteoporosis were 0.981, 0.999, 0.997 in the training cohort and 0.979, 0.943, 0.848 in the validation cohort. Furthermore, the AUCs of the previously mentioned models for the differentiation between osteopenia and normal were 0.994, 0.971, 0.996 in the training cohort and 0.990, 0.968, 0.908 in the validation cohort. The overall accuracy of the previously mentioned models for two-level classifications was 0.979, 0.955, 0.908 in the training cohort and 0.918, 0.885, 0.841 in the validation cohort. Decision curve analysis showed that all models had high clinical value. CONCLUSION: The feature fusion model can be used for osteoporosis and osteopenia prediction with improved predictive ability over a radiomics model or a DTL model alone.

3.
J Imaging Inform Med ; 37(4): 1548-1556, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38438697

RESUMEN

Coronary computed tomography angiography (CCTA) is an essential part of the diagnosis of chronic coronary syndrome (CCS) in patients with low-to-intermediate pre-test probability. The minimum technical requirement is 64-row multidetector CT (64-MDCT), which is still frequently used, although it is prone to motion artifacts because of its limited temporal resolution and z-coverage. In this study, we evaluate the potential of a deep-learning-based motion correction algorithm (MCA) to eliminate these motion artifacts. 124 64-MDCT-acquired CCTA examinations with at least minor motion artifacts were included. Images were reconstructed using a conventional reconstruction algorithm (CA) and a MCA. Image quality (IQ), according to a 5-point Likert score, was evaluated per-segment, per-artery, and per-patient and was correlated with potentially disturbing factors (heart rate (HR), intra-cycle HR changes, BMI, age, and sex). Comparison was done by Wilcoxon-Signed-Rank test, and correlation by Spearman's Rho. Per-patient, insufficient IQ decreased by 5.26%, and sufficient IQ increased by 9.66% with MCA. Per-artery, insufficient IQ of the right coronary artery (RCA) decreased by 18.18%, and sufficient IQ increased by 27.27%. Per-segment, insufficient IQ in segments 1 and 2 decreased by 11.51% and 24.78%, respectively, and sufficient IQ increased by 10.62% and 18.58%, respectively. Total artifacts per-artery decreased in the RCA from 3.11 ± 1.65 to 2.26 ± 1.52. HR dependence of RCA IQ decreased to intermediate correlation in images with MCA reconstruction. The applied MCA improves the IQ of 64-MDCT-acquired images and reduces the influence of HR on IQ, increasing 64-MDCT validity in the diagnosis of CCS.


Asunto(s)
Algoritmos , Angiografía por Tomografía Computarizada , Angiografía Coronaria , Aprendizaje Profundo , Humanos , Angiografía por Tomografía Computarizada/métodos , Femenino , Masculino , Persona de Mediana Edad , Angiografía Coronaria/métodos , Anciano , Artefactos , Procesamiento de Imagen Asistido por Computador/métodos , Tomografía Computarizada Multidetector/métodos , Vasos Coronarios/diagnóstico por imagen
4.
Math Biosci Eng ; 21(2): 2626-2645, 2024 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-38454699

RESUMEN

Calculating single-source shortest paths (SSSPs) rapidly and precisely from weighted digraphs is a crucial problem in graph theory. As a mathematical model of processing uncertain tasks, rough sets theory (RST) has been proven to possess the ability of investigating graph theory problems. Recently, some efficient RST approaches for discovering different subgraphs (e.g. strongly connected components) have been presented. This work was devoted to discovering SSSPs of weighted digraphs by aid of RST. First, SSSPs problem was probed by RST, which aimed at supporting the fundamental theory for taking RST approach to calculate SSSPs from weighted digraphs. Second, a heuristic search strategy was designed. The weights of edges can be served as heuristic information to optimize the search way of $ k $-step $ R $-related set, which is an RST operator. By using heuristic search strategy, some invalid searches can be avoided, thereby the efficiency of discovering SSSPs was promoted. Finally, the W3SP@R algorithm based on RST was presented to calculate SSSPs of weighted digraphs. Related experiments were implemented to verify the W3SP@R algorithm. The result exhibited that W3SP@R can precisely calculate SSSPs with competitive efficiency.

5.
Neoplasia ; 50: 100977, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38354688

RESUMEN

BACKGROUND: The inconformity (IC) between pathological and imaging remissions after neoadjuvant immunotherapy in patients with NSCLC can affect the evaluation of curative effect of neoadjuvant therapy and the decision regarding the chance of surgery. MATERIALS AND METHODS: Patients who achieved disease control(CR/PR/SD) after neoadjuvant chemoimmunotherapy from a clinical trial (NCT04326153) and after neoadjuvant chemotherapy during the same period were enrolled in this study. All patients underwent radical resection and systematic mediastinal lymphadenectomy after neoadjuvant treatments. The pathological remission, immunohistochemistry (CD4, CD8, CD20, CD56, FoxP3, CD68, CD163, CD11b tumor-infiltrating lymphocytes, or macrophages), and single-source dual-energy computed tomography (ssDECT) scans were assessed. The IC between imaging remission by CT and pathological remission was investigated. The underlying cause of IC, the correlation between IC and DFS, and prognostic biomarkers were explored. RESULTS: After neoadjuvant immunotherapy, enhanced immune killing and reduced immunosuppressive performance were observed. 70 % of neoadjuvant chemoimmunotherapy patients were in high/medium IC level. Massive necrosis and repair around and inside the cancer nest were the main pathological changes observed 30-45 days post-treatment with PD1/PD-L1 antibody and were the main causes of IC between the pathology and imaging responses after neoadjuvant immunotherapy. High IC and preoperative CD8 expression (H score ≥ 3) indicate a high pathological response rate and prolonged DFS. Iodine material density ssDECT images showed that the iodine content in the lesion causes hyperattenuation in post-neoadjuvant lesion in PCR patient. CONCLUSIONS: Compared to chemotherapy and targeted therapy, the efficacy of neoadjuvant immunotherapy was underestimated based on the RECIST criteria due to the unique antitumor therapeutic mechanism. Preoperative CD8+ expression and ssDECT predict this IC and evaluate the residual tumor cells. This is of great significance for screening immune beneficiaries and making more accurate judgments about the timing of surgery.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Yodo , Neoplasias Pulmonares , Humanos , Terapia Neoadyuvante , Microambiente Tumoral , Carcinoma de Pulmón de Células no Pequeñas/patología , Tomografía Computarizada por Rayos X , Inmunoterapia , Neoplasias Pulmonares/patología , Yodo/farmacología , Yodo/uso terapéutico
6.
Adv Mater ; 36(2): e2309531, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37985162

RESUMEN

The uniform deposition of perovskite light-emitting diodes (PeLEDs) and their integration with backplane thin-film transistors (TFTs) remain challenging for large-area display applications. Herein, an active-matrix PeLED display fabricated via the heterogeneous integration of cesium lead bromide LEDs and molybdenum disulfide (MoS2 )-based TFTs is presented. The single-source evaporation method enables the deposition of highly uniform perovskite thin films over large areas. PeLEDs are integrated with MoS2 TFTs to fabricate an active-matrix PeLED display with an 8 × 8 array, which exhibits excellent brightness control capability and high switching speed. This study demonstrates the potential of PeLEDs as candidates for next-generation displays and presents a novel approach for fabricating optoelectronic devices via the heterogeneous integration of 2D materials and perovskites, thereby paving the way toward the fabrication of practical future optoelectronic systems.

7.
Molecules ; 28(23)2023 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-38067524

RESUMEN

The paper describes a heterobimetallic mixed-ligand hexanuclear precursor [NaMn2(thd)4(OAc)]2 (1) (thd = 2,2,6,6-tetramethyl-3,5-heptadionate; OAc = acetate) that was designed based on its lithium homoleptic analogue, [LiMn2(thd)5], by replacing one of the thd ligands with an acetate group in order to accommodate 5-coordinated sodium instead of tetrahedral lithium ion. The complex, which is highly volatile and soluble in a variety of common solvents, has been synthesized by both the solid-state and solution methods. The unique "dimer-of-trimers" heterometallic structure consists of two trinuclear [NaMnII2(thd)4]+ units firmly bridged by two acetate ligands. X-ray diffraction techniques, DART mass spectrometry, ICP-OES analysis, and IR spectroscopy have been employed to confirm the structure and composition of the hexanuclear complex. Similar to the Li counterpart forming LiMn2O4 spinel material upon thermal decomposition, the title Na:Mn = 1:2 compound was utilized as the first single-source precursor for the low-temperature preparation of Na4Mn9O18 tunnel oxide. Importantly, four Mn sites in the hexanuclear molecule can be potentially partially substituted by other transition metals, leading to heterotri- and tetrametallic precursors for the advanced quaternary and quinary Na-ion oxide cathode materials.

8.
J Med Life ; 16(6): 862-867, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37675166

RESUMEN

High-quality and detailed CT scan images are crucial for accurate diagnosis. Factors such as image noise and slice thickness affect image quality. This study aimed to determine the optimal slice thickness that minimized image noise while maintaining sufficient diagnostic information using the single-source computed tomography head protocol. Single-source CT images were examined using the Linux Operating system Ge Revolution 64-slice CT scanner, and a combination of statical analysis and DICOM CT image analysis was employed. The single-source energy head CT protocol was used to investigate the effect of slice thickness on noise and visibility in images. Different values of slice thickness 0.625, 1.25, 2.5, 3.75, 5, 7.5, and 10 were prepared, and then quantitative analysis was performed. Thinner slice thickness decreased image noise, increased visibility, and improved detection. Therefore, the balance between changing the thickness of the slice with the diagnostic content and image noise must be considered. Maximum slice thickness enhances CT image detail and structure despite more noise. Based on the results, a slice thickness of 1.25mm was identified as the optimal choice for reducing image noise and achieving better and more accurate detection using the single-source computed tomography head protocol. The study revealed that image noise tends to increase with greater slice thickness according to the Linux operating system. These findings can serve as a valuable guide for quality control methods in CT centers, emphasizing the need to determine the appropriate slice thickness to ensure an accurate diagnosis.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Tomografía Computarizada por Rayos X , Humanos , Control de Calidad , Programas Informáticos
9.
ACS Appl Mater Interfaces ; 15(25): 30815-30825, 2023 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-37335626

RESUMEN

SiCxOy beaded carbon fibers were successfully fabricated for the first time using a facile and stable electrospinning and temperature process. The resulting fibers showcase a unique micro-nanocomposite structure, in which ß-SiC beads with a silica-enriched surface are strung together with defect carbon fibers, as confirmed by XRD, XPS, and HRTEM investigation. The SiCxOy beaded carbon fibers display efficient microwave absorption performance, with a minimum reflection loss of -58.53 dB and an effective absorption bandwidth of 5.92 GHz. A modified Drude-Lorentz model was developed for SiCxOy beaded carbon fibers to reveal the double-peaked feature of the permittivity of these fibers, which is in good agreement with experimental measurements. Moreover, simulations were performed to extract polarized electric fields and microwave energy volume losses within a typical distribution of SiCxOy beaded carbon fibers. It is concluded that the dipole relaxation and hopping migration of localized electrons give a superior contribution to the overall decay of the microwave energy. This study indicates that SiCxOy beaded carbon fibers with a unique micro-nanocomposite structure hold great promise for microwave absorption applications. Additionally, this fabrication strategy offers a unique approach to producing micro-nanocomposite structures and highlights their potential applications.

10.
Adv Sci (Weinh) ; 10(14): e2204488, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36951493

RESUMEN

High-entropy (HE) metal chalcogenides are a class of materials that have great potential in applications such as thermoelectrics and electrocatalysis. Layered 2D transition-metal dichalcogenides (TMDCs) are a sub-class of high entropy metal chalcogenides that have received little attention to date as their preparation currently involves complicated, energy-intensive, or hazardous synthetic steps. To address this, a low-temperature (500 °C) and rapid (1 h) single source precursor approach is successfully adopted to synthesize the hexernary high-entropy metal disulfide (MoWReMnCr)S2 . (MoWReMnCr)S2 powders are characterized by powder X-ray diffraction (pXRD) and Raman spectroscopy, which confirmed that the material is comprised predominantly of a hexagonal phase. The surface oxidation states and elemental compositions are studied by X-ray photoelectron spectroscopy (XPS) whilst the bulk morphology and elemental stoichiometry with spatial distribution is determined by scanning electron microscopy (SEM) with elemental mapping information acquired from energy-dispersive X-ray (EDX) spectroscopy. The bulk, layered material is subsequently exfoliated to ultra-thin, several-layer 2D nanosheets by liquid-phase exfoliation (LPE). The resulting few-layer HE (MoWReMnCr)S2 nanosheets are found to contain a homogeneous elemental distribution of metals at the nanoscale by high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) with EDX mapping. Finally, (MoWReMnCr)S2 is demonstrated as a hydrogen evolution electrocatalyst and compared to 2H-MoS2 synthesized using the molecular precursor approach. (MoWReMnCr)S2 with 20% w/w of high-conductivity carbon black displays a low overpotential of 229 mV in 0.5 M  H2 SO4 to reach a current density of 10 mA cm-2 , which is much lower than the overpotential of 362 mV for MoS2 . From density functional theory calculations, it is hypothesised that the enhanced catalytic activity is due to activation of the basal plane upon incorporation of other elements into the 2H-MoS2 structure, in particular, the first row TMs Cr and Mn.

11.
BMC Musculoskelet Disord ; 24(1): 100, 2023 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-36750927

RESUMEN

BACKGROUND: With the aging population of society, the incidence rate of osteoporosis is increasing year by year. Early diagnosis of osteoporosis plays a significant role in the progress of disease prevention. As newly developed technology, computed tomography (CT) radiomics could discover radiomic features difficult to recognize visually, providing convenient, comprehensive and accurate osteoporosis diagnosis. This study aimed to develop and validate a clinical-radiomics model based on the monochromatic imaging of single source dual-energy CT for osteoporosis prediction. METHODS: One hundred sixty-four participants who underwent both single source dual-energy CT and quantitative computed tomography (QCT) lumbar-spine examination were enrolled in a study cohort including training datasets (n = 114 [30 osteoporosis and 84 non-osteoporosis]) and validation datasets (n = 50 [12 osteoporosis and 38 non-osteoporosis]). One hundred seven radiomics features were extracted from 70-keV monochromatic CT images. With QCT as the reference standard, a radiomics signature was built by using least absolute shrinkage and selection operator (LASSO) regression on the basis of reproducible features. A clinical-radiomics model was constructed by incorporating the radiomics signature and a significant clinical predictor (age) using multivariate logistic regression analysis. Model performance was assessed by its calibration, discrimination and clinical usefulness. RESULTS: The radiomics signature comprised 14 selected features and showed good calibration and discrimination in both training and validation cohorts. The clinical-radiomics model, which incorporated the radiomics signature and a significant clinical predictor (age), also showed good discrimination, with an area under the receiver operating characteristic curve (AUC) of 0.938 (95% confidence interval, 0.903-0.952) in the training cohort and an AUC of 0.988 (95% confidence interval, 0.967-0.998) in the validation cohort, and good calibration. The clinical-radiomics model stratified participants into groups with osteoporosis and non-osteoporosis with an accuracy of 94.0% in the validation cohort. Decision curve analysis (DCA) demonstrated that the radiomics signature and the clinical-radiomics model were clinically useful. CONCLUSIONS: The clinical-radiomics model incorporating the radiomics signature and a clinical parameter had a good ability to predict osteoporosis based on dual-energy CT monoenergetic imaging.


Asunto(s)
Nomogramas , Tomografía Computarizada por Rayos X , Humanos , Anciano , Tomografía Computarizada por Rayos X/métodos , Envejecimiento , Curva ROC , Estudios Retrospectivos
12.
Small ; 19(16): e2206679, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36651137

RESUMEN

The development of a competent (pre)catalyst for the oxygen evolution reaction (OER) to produce green hydrogen is critical for a carbon-neutral economy. In this aspect, the low-temperature, single-source precursor (SSP) method allows the formation of highly efficient OER electrocatalysts, with better control over their structural and electronic properties. Herein, a transition metal (TM) based chalcogenide material, nickel sulfide (NiS), is prepared from a novel molecular complex [NiII (PyHS)4 ][OTf]2 (1) and utilized as a (pre)catalyst for OER. The NiS (pre)catalyst requires an overpotential of only 255 mV to reach the benchmark current density of 10 mA cm-2 and shows 63 h of chronopotentiometry (CP) stability along with over 95% Faradaic efficiency in 1 m KOH. Several ex situ measurements and quasi in situ Raman spectroscopy uncover that NiS irreversibly transformed to a carbonate-intercalated γ-NiOOH phase under the alkaline OER conditions, which serves as the actual active structure for the OER. Additionally, this in situ formed active phase successfully catalyzes the selective oxidation of alcohol, aldehyde, and amine-based organic substrates to value-added chemicals, with high efficiencies.

13.
ACS Nano ; 2023 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-36625593

RESUMEN

A synthetic platform for industrially applicable two-dimensional (2D) semiconductors that addresses the paramount issues associated with large-scale production, wide-range photosensitive materials, and oxidative stability has not yet been developed. In this study, we attained the 6 in. scale production of 2D SnSe semiconductors with spatial homogeneity using a rational synthetic platform based on the thermal decomposition of solution-processed single-source precursors. The long-range structural and chemical homogeneities of the 2D SnSe layers are manifested using comprehensive spectroscopic analyses. Furthermore, the capability of the SnSe-based photodetectors for broadband photodetection is distinctly verified. The photoresponsivity and detectivity of the SnSe-based photodetectors are 5.89 A W-1 and 1.8 × 1011 Jones at 532 nm, 1.2 A W-1 and 3.7 × 1010 Jones at 1064 nm, and 0.14 A W-1 and 4.3 × 109 Jones at 1550 nm, respectively. The minimum rise times for the 532 and 1064 nm lasers are 62 and 374 µs, respectively. The photoelectrical analysis of the 5 × 5 SnSe-based photodetector array reveals 100% active devices with 95.06% photocurrent uniformity. We unequivocally validated that the air and thermal stabilities of the photocurrent yielded from the SnSe-based photodetector are determined to be >30 d in air and 160 °C, respectively, which are suitable for optoelectronic applications.

14.
Materials (Basel) ; 15(23)2022 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-36499872

RESUMEN

At present, conjugated thermolysis of metal-containing monomers is widely used as single-source precursors to obtain new metal- and metal oxide-containing nanocomposites. In this study, a detailed analysis of the main stages of conjugated thermolysis of silver itaconate was carried out. The obtained nanocomposites containing silver nanoparticles are evenly distributed in a stabilizing carbon matrix. The structural characteristics and properties of the resulting nanomaterials were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). We have developed a method of test analysis of chlorides using paper modified with the obtained silver-containing nanocomposites. The analysis technique is based on the in situ conversion of chlorides to molecular chlorine, its dynamic release, and colorimetric detection using NP-modified paper test strips. A simple installation device is described that allows this combination to be realized. The proposed approach seems promising for nanoparticle-based determinations of other analytes that can be converted into volatile derivatives.

15.
Small ; 18(40): e2203653, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36048144

RESUMEN

High-quality lead sulfide (PbS) films are deposited on selected substrate chemistries by an H2 S-free metal-organic chemical vapor deposition (MOCVD) process using a single-source metal-organic complex (Pb(dmampS)2 ). The complex is synthesized via a salt metathesis reaction between PbCl2  and lithium 1-(dimethylamino)-2-methylpropane-2-thiolate (Li(dmampS)) in diethyl ether. Subsequent film deposition is conducted by a simple thermolysis process in the absence of H2 S, yet chemical and structural analysis confirm chemically stoichiometric and homogenous films. Mechanistic studies with electron impact mass spectroscopy (EIMS) and gas chromatography mass spectroscopy (GCMS) suggest the selective cleavage of C-S bonds in the complex as the reason for the facile PbS formation with negligible impurity incorporation. The high crystallinity, low hole concentrations, and charge transport properties comparable and in many cases superior to films produced by atomic layer deposition (ALD) testify to the quality of the films. Lastly, rigid and flexible photodetectors fabricated with the PbS films exhibit considerably high photocurrents, reliable switching characteristics, and high sensitivity over a broad spectral bandwidth, highlighting the potential for realizing practical broadband photodetectors.

16.
Nano Lett ; 22(18): 7432-7440, 2022 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-36069429

RESUMEN

It has been long known that low molecular weight resists can achieve a very high resolution, theoretically close to the probe diameter of the electron beam lithography (EBL) system. Despite technological improvements in EBL systems, the advances in resists have lagged behind. Here we demonstrate that a low-molecular-mass single-source precursor resist (based on cadmium(II) ethylxanthate complexed with pyridine) is capable of a achieving resolution (4 nm) that closely matches the measured probe diameter (∼3.8 nm). Energetic electrons enable the top-down radiolysis of the resist, while they provide the energy to construct the functional material from the bottom-up─unit cell by unit cell. Since this occurs only within the volume of resist exposed to primary electrons, the minimum size of the patterned features is close to the beam diameter. We speculate that angstrom-scale patterning of functional materials is possible with single-source precursor resists using an aberration-corrected electron beam writer with a spot size of ∼1 Å.

17.
Materials (Basel) ; 15(8)2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35454590

RESUMEN

The submerged arc furnace (SAF) has become the equipment of choice to produce manganese ferro-alloy. Furnace operators aim to reduce the cost of production by better understanding the role played by the various raw materials involved in the process. Coke is one of the key raw materials fed into the SAF; it plays three key roles in electric furnaces: as a reducing agent, as a source of carbon found in the alloy, and as a resistive element facilitating heat generation in the furnace. The heat generated plays two key functions in the furnace: ensuring both the metal and the slag have a sufficient low viscosity, and providing the heat required to support endothermic reactions. This study investigated the ambient-temperature and high-temperature resistivity characteristics of coke made from single-source coals. The measurement of coke resistivity was performed using the Kelvin (four-point) technique. The results showed a statistically significant difference in mean resistivity between cokes made from different coals. It was observed that coke resistivity generally decreased with increasing temperatures. Raman spectroscopy showed that the structural order of coke changes with increasing temperature.

18.
Forensic Sci Int Genet ; 58: 102689, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35316721

RESUMEN

In forensic applications, there is an increasing demand for the analysis of DNA profiles arising from missing person identification (MPI) cases. A specific DNA profile may originate from a single source or more than one contributor (i.e., a DNA mixture). When direct references are not available, indirect relative references can be used to identify missing persons by kinship analysis. As a novel kind of multiallelic marker, microhaplotypes have proven promising for relatedness determination and mixture deconvolution. Herein, we developed a large panel of 185 microhaplotype markers and demonstrated its application in different scenarios of relationship inference through a simulation study and real pedigree analysis, combined with probabilistic genotyping models for data interpretation. Based on single-source profiles, it was shown that the present microhaplotype panel was sufficient for pairwise close relative testing (parent/child, full-sibling and 2nd-degree relative). For more distant relatives (3rd-degree relatives), there was a clear improvement when data from one well-chosen extra relative were available. We further sought to evaluate the theoretical systematic effectiveness and actual performance of microhaplotype markers in identifying the contribution of a missing pedigree member to a two-person mixture (as a minor donor). It was observed that 100% correct assignments were made in the balanced mixtures (with no dropout) when referenced to close relatives. When the mixture profiles suffered from dropout, incorrect assignments of minor donors were markedly associated with relatedness and the dropout level. Meanwhile, the studied scenarios generally exhibited zero or very low false-positive rates, indicating a low probability of incorrectly assigning an unrelated contributor as a close relative of the reference. Our results indicate that microhaplotype data can be reliably interpreted for identifying missing persons through kinship analysis based on DNA profiles of single-source samples or two-person mixtures. Furthermore, this study could be extended to more complex scenarios, such as determining the relatedness of contributors in (or among) mixed DNA profiles, if combined with different statistical frameworks.


Asunto(s)
Dermatoglifia del ADN , ADN , Niño , ADN/análisis , ADN/genética , Dermatoglifia del ADN/métodos , Humanos , Modelos Estadísticos , Linaje , Análisis de Secuencia de ADN/métodos
19.
Chem Asian J ; 17(7): e202200087, 2022 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-35156313

RESUMEN

Herein, we demonstrate a vacuum-based evaporation approach to fabricate organic-inorganic perovskite thin films by using phase-formed halide perovskite nanoparticles (NPs) as a precursor/source. We are able to consistently obtain MAPbX3 (MA=CH3 NH3 and X=Cl, Br or I) thin films at various substrates (e. g., glass, ITO, or plastic). The perovskite phase formation in thin film form is confirmed by x-ray diffraction (XRD) studies. Small micro-strain (tensile) values of 1.64×10-3 , 1.42×10-3 and 6.85×10-4 obtained for MAPbCl3 , MAPbBr3 and MAPbI3 films respectively from Williamson-Hall equation indicate low structural distortions in perovskite thin films. The absorption spectra of thin films show sharp band edge having direct band gap, which is followed by narrow full width at half maxima (FWHM ∼0.1 eV) of the emission peak. Thin films of MAPbCl3 , MAPbBr3 and MAPbI3 show direct band gap of 3.1 eV, 2.4 eV and 1.6 eV, respectively. Small Urbach energy values of 33 meV, 44 meV and 66 meV for MAPbCl3 , MAPbBr3 and MAPbI3 films respectively indicates low defect density in various perovskite films. Scanning electron microscopy (SEM) along with energy-dispersive X-ray spectroscopy (EDS) shows high surface coverage and uniform chemical composition of MAPbX3 (X=Cl, Br and I) thin films deposited by the present method. We have successfully controlled the film thickness from 250 nm to 1 µm by varying the nanoparticle precursor amount. The perovskite thin films deposited by the present method are highly stable against the degradation under ambient conditions. Systematic XRD studies along with absorption data demonstrate that the MAPbCl3 and MAPbBr3 films stored under ambient conditions remained stable for more than 30 days and MAPbI3 films for more than 7 days.

20.
Nanomaterials (Basel) ; 11(12)2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34947621

RESUMEN

The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P-31c, Z = 2) vary in the following intervals: a = 9.2332(3)-9.2566(6); c = 9.9512(12)-9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni-Mo-W phases. The formation of carbon-nitride phases at certain stages of heating up to 1000 °C were shown.

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