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1.
Adv Sci (Weinh) ; : e2309062, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38696653

RESUMO

Atherosclerotic cardiovascular disease (ASCVD) has become the leading cause of death worldwide, and early diagnosis and treatment of atherosclerosis (AS) are crucial for reducing the occurrence of acute cardiovascular events. However, early diagnosis of AS is challenging, and oral anti-AS drugs suffer from limitations like imprecise targeting and low bioavailability. To overcome the aforementioned shortcomings, Cur/MOF@DS is developed, a nanoplatform integrating diagnosis and treatment by loading curcumin (Cur) into metal-organic frameworks with nanozymes and magnetic resonance imaging (MRI) properties. In addition, the surface-modification of dextran sulfate (DS) enables PCN-222(Mn) effectively target scavenger receptor class A in macrophages or foam cells within the plaque region. This nanoplatform employs mechanisms that effectively scavenge excessive reactive oxygen species in the plaque microenvironment, promote macrophage autophagy and regulate macrophage polarization to realize lipid regulation. In vivo and in vitro experiments confirm that this nanoplatform has outstanding MRI performance and anti-AS effects, which may provide a new option for early diagnosis and treatment of AS.

2.
J Asthma ; : 1-13, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38647226

RESUMO

Objective: The aim of this study was to identify genetic biomarkers and cellular communications associated with severe asthma in microarray data sets and single cell data sets. The potential gene expression levels were verified in a mouse model of asthma.Methods: We identified differentially expressed genes from the microarray datasets (GSE130499 and GSE63142) of severe asthma, and then constructed models to screen the most relevant biomarkers to severe asthma by machine learning algorithms (LASSO and SVM-RFE), with further validation of the results by GSE43696. Single-cell datasets (GSE193816 and GSE227744) were identified for potential biomarker-specific expression and intercellular communication. Finally, The expression levels of potential biomarkers were verified with a mouse model of asthma.Results: The 73 genes were differentially expressed between severe asthma and normal control. LASSO and SVM-RFE recognized three genes BCL3, DDIT4 and S100A14 as biomarkers of severe asthma and had good diagnostic effect. Among them, BCL3 transcript level was down-regulated in severe asthma, while S100A14 and DDIT4 transcript levels were up-regulated. The transcript levels of the three genes were confirmed in the mouse model. Infiltration of neutrophils and mast cells were found to be increased in severe asthma and may be associated with bronchial epithelial cells through BMP and NRG signalingConclusions: We identified three differentially expressed genes (BCL3, DDIT4 and S100A14) of diagnostic significance that may be involved in the development of severe asthma and these gene expressions could be serviced as biomarker of severe asthma and investigating the function roles could bring new insights into the underlying mechanisms.

3.
Sci Adv ; 10(14): eadk5229, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38569034

RESUMO

The origin of the cosmic magnetic field remains an unsolved mystery, relying not only on specific dynamo processes but also on the seed field to be amplified. Recently, the diffuse radio emission and Faraday rotation observations reveal that there has been a microgauss-level magnetic field in intracluster medium in the early universe, which places strong constraints on the strength of the initial field and implies the underlying kinetic effects; the commonly believed Biermann battery can only provide extremely weak seed of 10-21 G. Here, we present evidence for the spontaneous Weibel-type magnetogenesis in laser-produced weakly collisional plasma with the three-dimensional synchronous proton radiography, where the distribution anisotropy directly arises from the temperature gradient, even without the commonly considered interpenetrating plasmas or shear flows. This field can achieve sufficient strength and is sensitive to Coulomb collision. Our results demonstrate the importance of kinetics in magnetogenesis in weakly collisional astrophysical scenarios.

4.
Opt Express ; 32(6): 9602-9609, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38571190

RESUMO

The thin flyer is a small-scale flying object, which is well known as the core functional element of the initiator. Understanding how flyers perform has been a long-standing issue in detonator science. However, it remains a significant challenge to explore how the flyer is formed and functions in the barrel of the initiator via tabletop devices. In this study, we present dynamic and unprecedented images of flyer in barrel via high intensity short-pulse laser. Advanced radiography, coupled with a high-intensity picosecond laser X-ray source, has enabled the provision of state-of-the-art radiographs in a single-shot experiment for observing micron-scale flyer formation in a hollow cylinder in nanoseconds. The flyer was clearly visible in the barrel and was accelerated and restricted differently from that without the barrel. This first implementation of a tabletop X-ray source provided a new approach for capturing dynamic photographs of small-scale flying objects, which were previously reported to be accessible only via an X-ray phase-contrast imaging system at the advanced photon source. These efforts have led to a significant improvement of radiographic capability and a greater understanding of the mechanisms of "burst" of exploding foil initiators for this application.

5.
Ann Vasc Surg ; 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38599492

RESUMO

OBJECTIVES: The Talos stent-graft has extended length to improve aortic remodeling, and distal porous design to decrease the rate of spinal cord ischemia. This study retrospectively analyzed its mid-term outcomes for uncomplicated type B aortic dissection in a multicenter study. METHODS: The primary safety endpoint was 30-day major adverse events, including all-cause mortality, dissection-related mortality, conversion to open surgery, and device-related adverse events. The primary efficacy endpoint was treatment success at 12 months post-operation, defined as no technical failure or secondary dissection-related reintervention. The survival status of the patients was visualized using the Kaplan-Meier curve. Aortic growth was assessed at four levels, and spinal cord ischemia was evaluated at 12 months. RESULTS: 113 patients participated with a mean age of 54.4 (11.1) years and 71.7% (81/113) were male. The 30-day mortality was 0.9% (1/113), no conversions to open surgery or device-related adverse events were recorded. The 12-month treatment success rate was 99.1% (112/113), with no dissection-related reinterventions. There was no spinal cord or visceral ischemia at 12 months. At a median of 34 months follow-up, 9 further deaths were recorded and the 3-year survival rate was 91.7%. The percentage of aortic growth was 1.8% (2/111) at the tracheal bifurcation, 3.6% (4/111) below the left atrium, 6.0% (5/83) above the celiac artery, and 12.1% (9/74) below the lower renal artery. The total thrombosis rate of the false lumen at the stented segment was 80.5% (91/113). CONCLUSIONS: The results showed satisfactory results of Talos stent-graft in terms of safety and efficacy. More data are needed to confirm the long-term performance.

6.
Ann Vasc Surg ; 104: 307-314, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38599487

RESUMO

BACKGROUND: This study aims to conduct a comparative analysis of the clinical efficacy and safety between pharmacomechanical thrombectomy (PMT) and catheter-directed thrombolysis (CDT) in the context of acute lower-extremity deep venous thrombosis (LEDVT). METHODS: A retrospective review of our institution's patient database spanning from February 2011 to December 2019 was performed to identify cases of acute LEDVT. The patients were categorized into 2 distinct groups based on the thrombolytic interventions administered: the PMT group, specifically denoting PMT with AngioJet in our investigation, and the CDT group. Comprehensive data sets encompassing patient demographics, risk factors, procedural specifics, thrombolysis grading, and complications were collected. Subsequent follow-up evaluations at the 2-year mark posttreatment included assessments of postthrombotic syndrome (PTS) and the quality of life. RESULTS: Among the 348 patients identified (mean age: 50.12 ± 15.87 years; 194 females), 200 underwent CDT during the early stage (2011 to 2017), while 148 received PMT between 2017 and 2019. Baseline data between the 2 groups exhibited no statistically significant differences. Thrombus scores significantly decreased in both cohorts posttherapy (each P < 0.001).Patients subjected to PMT demonstrated higher thrombolysis rates (77.35 ± 9.44% vs. 50.85 ± 6.72%), reduced administration of the thrombolytic agent urokinase [20 (20€20) vs. 350 (263€416), P < 0.001], larger limb circumference differences (above the knee: 6.03 ± 1.76 cm vs. 4.51 ± 1.82 cm, P < 0.001; below the knee: 2.90 ± 1.16 cm vs. 2.51 ± 0.90 cm, P < 0.001), and shorter lengths of stay (7.19 ± 3.11 days vs. 12.33 ± 4.77 days, P < 0.001). However, the PMT group exhibited a higher decline in hemoglobin levels (13.41 ± 10.59 g/L vs. 10.88 ± 11.41 g/L, P = 0.038) and an increase in creatinine levels [9.58 (2.32€15.82) umol/L vs. 4.53 (2.87€6.08) umol/L, P < 0.001] compared to the CDT group. No statistically significant differences were observed in the numbers of balloon angioplasty, stent implantation (each P > 0.050), and minor and major complications between the 2 groups. At the 1-year follow-up, PTS occurred in 13.51% of the PMT group compared to 26% of the CDT group (P = 0.025), with a higher incidence of moderate-severe PTS in the CDT group (8% vs. 2.7%, P = 0.036). At the 2-year follow-up, PTS was observed in 16.2% of the PMT group and 31.5% in the CDT group, P = 0.004. Preoperative and postoperative D-values of 36-Item Short Form Health Survey (SF-36) Physical Component Summary and SF-36 Mental Component Summary showed no statistically significant between-group differences. CONCLUSIONS: In our institutional experience, both PMT and CDT have proven to be effective and safe therapeutic approaches for managing acute LEDVT. PMT, in particular, demonstrated superior efficacy in achieving thrombosis resolution and mitigating the risk of PTS, affirming its role as a favorable intervention in this clinical context.

7.
Rev Sci Instrum ; 95(1)2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38197767

RESUMO

The Thomson parabola ion spectrometer is vulnerable to intense electromagnetic pulses (EMPs) generated by a high-power laser interacting with solid targets. A metal shielding cage with a circular aperture of 1 mm diameter is designed to mitigate EMPs induced by a picosecond laser irradiating a copper target in an experiment where additionally an 8-ns delayed nanosecond laser is incident into an aluminum target at the XG-III laser facility. The implementation of the shielding cage reduces the maximum EMP amplitude inside the cage to 5.2 kV/m, and the simulation results indicate that the cage effectively shields electromagnetic waves. However, the laser-accelerated relativistic electrons which escaped the target potential accumulate charge on the surface of the cage, which is responsible for the detected EMPs within the cage. To further alleviate EMPs, a lead wall and an absorbing material (ECCOSORB AN-94) were added before the cage, significantly blocking the propagation of electrons. These findings provide valuable insights into EMP generation in large-scale laser infrastructures and serve as a foundation for electromagnetic shielding design.

8.
Hamostaseologie ; 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38224959

RESUMO

Venous thromboembolism (VTE) represents a worldwide health challenge, impacting millions of people each year. The genesis of venous thrombosis is influenced in part by genetic components. Hereditary thrombosis is described as a genetically determined susceptibility to VTE. In the present study, a male patient was referred to our department presenting with multiple venous thrombosis events in different locations. Given a lack of identifiable risk factors, we aimed to investigate the possible genetic factor underlying venous thrombosis. Whole-exome sequencing was employed to examine genes linked to inherited thrombophilia in the proband. Putative variants were subsequently confirmed through Sanger sequencing within the family. The proband was identified as carrying two genetic mutations. One is the novel c.400G > C (p.E134Q) mutation affecting the final nucleotide of exon 5 in the PROC gene, potentially impacting splicing. The other is a previously reported heterozygous nonsense variant c.1016G > A (p.W339X) in the SERPINC1 gene. The proband inherited the former from her mother and the latter from her father. The presence of digenic inheritance in the patient reflects the complex phenotype of venous thrombosis and demonstrates the significance of an unbiased approach to detect pathogenic variants, especially in patients with a high risk of hereditary thrombosis.

9.
Sci Rep ; 14(1): 60, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38168909

RESUMO

RNA N6-methyladenosine (m6A) regulators play essential roles in diverse biological processes, including immune responses. Mounting evidence suggests that their dysregulation is intricately linked to numerous diseases. However, the role of m6A-associated genes in carotid atherosclerosis and their relationship with aging and immune cells remain unclear. Analyze the expression profiles of m6A-related genes in carotid atherosclerosis-related datasets. Based on the expression patterns of m6A-related genes, perform consistent clustering analysis of carotid atherosclerosis samples and investigate associated immune cell infiltration patterns and aging characteristics. Develop an m6A prediction model specific to carotid atherosclerosis and analyze the relationships between immune cells infiltration and aging features. The m6A methylation modification level exhibited a substantial decrease in early-stage carotid atherosclerosis samples compared to late-stage carotid atherosclerosis samples. Subsequently, two distinct m6A subtypes were defined through consensus clustering analysis, with the lower m6A modification level group showing associations with heightened immune cell infiltration and increased expression of aging-related genes. A model composed of five m6A-related genes was formulated, and the results indicated that this model possesses effective predictive and therapeutic capabilities for carotid atherosclerosis. Furthermore, the downregulation of YTHDC1 expression resulted in elevated expression of inflammatory factors and a decrease in the expression of the aging-related gene RGN. Single-cell data analysis suggests that the reduced expression of YTHDC1 may decrease the degradation of inflammation-related factors in macrophages, leading to a highly inflammatory state in the carotid artery wall. Furthermore, the sustained release of inflammatory factors may increase the expression of the aging-related gene RGN in vascular smooth muscle cells, further exacerbating the progression of atherosclerosis. A reduced level of m6A methylation modification could enhance inflammation and expedite cellular aging, thereby contributing to the development of carotid atherosclerosis.


Assuntos
Doenças das Artérias Carótidas , Humanos , Doenças das Artérias Carótidas/genética , Artéria Carótida Primitiva , Inflamação
11.
BMC Cancer ; 23(1): 943, 2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37803307

RESUMO

BACKGROUND: Nephrectomy, whether in the era of cytokine therapy or targeted therapy, has an important role in the treatment of metastatic renal cell carcinoma. With the advent of immunotherapy, immunotherapy combined with targeted therapy has become the mainstream of systemic therapy, but the role of nephrectomy in metastatic renal cell carcinoma is unclear. In this study, we retrospectively analyzed the impact of nephrectomy on survival in patients with metastatic renal cell carcinoma who received immune-targeted therapy. METHODS: Patients with metastatic renal cell carcinoma who received immune-targeted therapy at three centers between May 17, 2019 and August 1, 2022 were collected, who were divided into two groups based on whether nephrectomy was performed or not. Survival, response rate and adverse event were compared between the two groups. The primary end point was progression free survival, Subgroup analysis and univariate and multivariable prognostic analyses were also assessed. RESULTS: With a median follow-up time of 29.3 months (95% CI 28.5-30.2), 165 patients were recruited and divided into two groups based on whether they underwent nephrectomy or not. There were 68 patients in the non-nephrectomy group, 97 in the nephrectomy group. Compared to patients treated with immune-targeted therapy, patients treated with immune-targeted therapy plus nephrectomy were able to achieve survival benefits, with a median PFS of 10.8 months (95% CI 8.3-13.3) and 14.4 months (95% CI 12.6-16.2), respectively, as well as an HR of 0.476 (95% CI 0.323-0.701, p = 0.0002). The 12-month and 18-month PFS rates were 30.9% versus 60.8% and 7.4% versus 25.8%, respectively. The objective response rate (ORR) was 52.9% and 60.8%, respectively, in the non-nephrectomy and nephrectomy groups (p = 0.313), and the disease control rate (DCR) was 75% and 83.5%, respectively (p = 0.179). The most common adverse events related to treatment were hypothyroidism, immune-related pneumonitis and rash. Multivariate analysis showed that primary tumor nephrectomy prior to immune-targeted therapy, clear cell renal carcinoma and oligo metastasis were independent prognostic factors. CONCLUSIONS: Nephrectomy may provide PFS benefit with tolerable safety for patients with metastatic renal cell carcinoma who receive immune-targeted therapy. In multivariate analysis, nephrectomy, clear cell carcinoma, and oligo-organ metastasis were found to be favorable independent prognostic factors.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Humanos , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/cirurgia , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/cirurgia , Neoplasias Renais/patologia , Estudos Retrospectivos , Prognóstico , Nefrectomia
12.
Front Pharmacol ; 14: 1280428, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37818187

RESUMO

Background: Bladder cancer is a common urological cancer associated high significant morbidity and mortality rates. Immunotherapy has emerged as a promising treatment option, although response rates vary among patients. Glycosylation has been implicated in tumorigenesis and immune regulation. However, our current comprehensive understanding of the role of glycosylation in bladder cancer and its clinical implications is limited. Methods: We constructed a training cohort based on the downloaded TCGA-BLCA dataset, while additional datasets (Xiangya cohort, GSE32894, GSE48075, GSE31684, GSE69795 and E-MTAB-1803) from Xiangya hospital, GEO and ArrayExpress database were obtained and used as validation cohorts. To identify glycosylation-related genes associated with prognosis, univariate Cox regression and LASSO regression were performed. A Cox proportional hazards regression model was then constructed to develop a risk score model. The performance of the risk score was assessed in the training cohort using Kaplan-Meier survival curves and ROC curves, and further validated in multiple validation cohorts. Results: We classified patients in the training cohort into two groups based on glycosylation-related gene expression patterns: Cluster 1 and Cluster 2. Prognostic analysis revealed that Cluster 2 had poorer survival outcomes. Cluster 2 also showed higher levels of immune cell presence in the tumor microenvironment and increased activation in key steps of the cancer immune response cycle. We developed an independent prognostic risk score (p < 0.001) and used it to construct an accurate prognostic prediction nomogram. The high glycosylation risk score group exhibited higher tumor immune cell infiltration, enrichment scores in immune therapy-related pathways, and a tendency towards a basal subtype. Conversely, the low-risk score group had minimal immune cell infiltration and tended to have a luminal subtype. These findings were consistent in our real-world Xiangya cohort. Conclusion: This multi-omics glycosylation score based on these genes reliably confirmed the heterogeneity of bladder cancer tumors, predicted the efficacy of immunotherapy and molecular subtypes, optimizing individual treatment decisions.

13.
J Med Imaging (Bellingham) ; 10(5): 055501, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37767114

RESUMO

Purpose: The objective assessment of image quality (IQ) has been advocated for the analysis and optimization of medical imaging systems. One method of computing such IQ metrics is through a numerical observer. The Hotelling observer (HO) is the optimal linear observer, but conventional methods for obtaining the HO can become intractable due to large image sizes or insufficient data. Channelized methods are sometimes employed in such circumstances to approximate the HO. The performance of such channelized methods varies, with different methods obtaining superior performance to others depending on the imaging conditions and detection task. A channelized HO method using an AE is presented and implemented across several tasks to characterize its performance. Approach: The process for training an AE is demonstrated to be equivalent to developing a set of channels for approximating the HO. The efficiency of the learned AE-channels is increased by modifying the conventional AE loss function to incorporate task-relevant information. Multiple binary detection tasks involving lumpy and breast phantom backgrounds across varying dataset sizes are considered to evaluate the performance of the proposed method and compare to current state-of-the-art channelized methods. Additionally, the ability of the channelized methods to generalize to images outside of the training dataset is investigated. Results: AE-learned channels are demonstrated to have comparable performance with other state-of-the-art channel methods in the detection studies and superior performance in the generalization studies. Incorporating a cleaner estimate of the signal for the detection task is also demonstrated to significantly improve the performance of the proposed method, particularly in datasets with fewer images. Conclusions: AEs are demonstrated to be capable of learning efficient channels for the HO. The resulting significant increase in detection performance for small dataset sizes when incorporating a signal prior holds promising implications for future assessments of imaging technologies.

14.
Sci Total Environ ; 905: 167027, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-37717779

RESUMO

Microbial communities play a vital role in urban river biogeochemical cycles. However, the seasonal variations in microbial community characteristics, particularly phylogenetic group-based community assembly and species coexistence, have not been extensively investigated. Here, we systematically explored the microbiome characteristics and assembly mechanisms of urban rivers in different seasons using 16S rRNA gene sequencing and multivariate statistical methods. The results indicated that the microbial community presented significant temporal heterogeneity in different seasons, and the diversity decreased from spring to winter. The phylogenetic group-based microbial community assembly was governed by dispersal limitation and drift in spring, summer, and autumn but was structured by homogeneous selection in winter. Moreover, the main functions of nitrification, denitrification, and methanol oxidation were susceptible to dispersal limitation and drift processes, whereas sulfate respiration and aromatic compound degradation were controlled by dispersal limitation and homogeneous selection. Network analyses indicated that network complexity decreased and then increased with seasonal changes, while network stability showed the opposite trend, suggesting that higher complexity and diversity reduced community stability. Temperature was determined to be the primary driver of microbial community structure and assembly processes in different seasons based on canonical correspondence analysis and linear regression analysis. In conclusion, seasonal variation drives the dynamics of microbial community assembly and species coexistence patterns in urban rivers. This study provides new insights into the generation and maintenance of microbial community diversity in urban rivers under seasonal change conditions.


Assuntos
Microbiota , Rios , Estações do Ano , Filogenia , RNA Ribossômico 16S/genética
15.
Opt Express ; 31(19): 30486-30494, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37710589

RESUMO

Traditional spiral zone plates (SZPs) have been widely used to generate optical vortices, but this structure suffers from multiple focuses. To eliminate high-order foci, the current method is to design a binary structure that has a sinusoidal transmittance function along the radial direction. With the rapid development of artificial neural networks, they can provide alternative methods to design novel SZPs with a single focus. In this paper, we first propose the concept of generalized binary spiral zone plates (GBSZPs), and train a feedforward neural network (FNN) to obtain the mapping relationship between the relative intensity of each focus and the structural parameters of GBSZPs. Then the structural parameters of GBSZPs with a single focus were predicted by the trained FNN. It is found by simulations and experiments that the intensities of high-order foci can be as low as 0.2% of the required first order. By analyzing the radial transmittance function, it is found that this structure has a different distribution function from the previous radial sinusoidal function, which reveals that the imperfect radial sinusoidal form also can guide the design of binary zone plates to eliminate high-order foci diffraction. These findings are expected to direct new avenue towards improving the performance of optical image processing and quantum computation.

16.
Nanoscale Adv ; 5(16): 4158-4166, 2023 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-37560419

RESUMO

Although silicon has a high volumetric energy density as an anode material for Li-ion batteries, its volumetric expansion and sluggish Li+ migration kinetics need to be urgently addressed. In this work, cage-like structure materials (HRPOSS) derived from the in situ hydrogen reduction of polyhedral oligomeric silsesquioxane (T8-type POSS) were constructed as an Si@C anode for Li-ion batteries. Benefiting from the intriguing features of the Si/N double gradient and even-distributed silicon, HRPOSS-6 exhibited faint volume changes and fast ion-electron kinetics. Moreover, the uniformly immobilized nano-silicic and concentration gradient were favorable for accelerated ion migration. Therefore, HRPOSS-6 exhibited good electrochemical performances given that its cage structure could relieve the volume expansion. HRPOSS-6 demonstrated a high reversible capacity of 1814.1 mA h g-1 and long cycling performance after 200 cycles with 635 mA h g-1 at a current density of 0.5 A g-1. Accordingly, this Si/C/N composite exhibited great potential for high energy Li-ion batteries, where the corresponding full-cell (HRPOSS-6//LiNi0.6Co0.2Mn0.2O2) showed a cycle life of 200 cycles with over 80% capacity retention at rate of 1C. This work exploits the concentration gradients of dual elements for the capacity improvement of Si anodes and offers insight into the development of high-performance Si@C anode materials for advanced Li-ion batteries.

17.
IEEE Trans Med Imaging ; 42(12): 3715-3724, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37578916

RESUMO

Medical imaging systems are often evaluated and optimized via objective, or task-specific, measures of image quality (IQ) that quantify the performance of an observer on a specific clinically-relevant task. The performance of the Bayesian Ideal Observer (IO) sets an upper limit among all observers, numerical or human, and has been advocated for use as a figure-of-merit (FOM) for evaluating and optimizing medical imaging systems. However, the IO test statistic corresponds to the likelihood ratio that is intractable to compute in the majority of cases. A sampling-based method that employs Markov-chain Monte Carlo (MCMC) techniques was previously proposed to estimate the IO performance. However, current applications of MCMC methods for IO approximation have been limited to a small number of situations where the considered distribution of to-be-imaged objects can be described by a relatively simple stochastic object model (SOM). As such, there remains an important need to extend the domain of applicability of MCMC methods to address a large variety of scenarios where IO-based assessments are needed but the associated SOMs have not been available. In this study, a novel MCMC method that employs a generative adversarial network (GAN)-based SOM, referred to as MCMC-GAN, is described and evaluated. The MCMC-GAN method was quantitatively validated by use of test-cases for which reference solutions were available. The results demonstrate that the MCMC-GAN method can extend the domain of applicability of MCMC methods for conducting IO analyses of medical imaging systems.


Assuntos
Teorema de Bayes , Humanos , Cadeias de Markov , Método de Monte Carlo
18.
Materials (Basel) ; 16(13)2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37445057

RESUMO

X-ray detectors have numerous applications in medical imaging, industrial inspection, and crystal structure analysis. Gallium oxide (Ga2O3) shows potential as a material for high-performance X-ray detectors due to its wide bandgap, relatively high mass attenuation coefficient, and resistance to radiation damage. In this study, we present Sn-doped Ga2O3 microwire detectors for solar-blind and X-ray detection. The developed detectors exhibit a switching ratio of 1.66 × 102 under X-ray irradiation and can operate stably from room temperature to 623 K, which is one of the highest reported operating temperatures for Ga2O3 X-ray detectors to date. These findings offer a promising new direction for the design of Ga2O3-based X-ray detectors.

19.
Opt Express ; 31(12): 19266-19277, 2023 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-37381345

RESUMO

The axiparabola is a novel reflective element proposed in recent years, which can generate a long focal line with high peak intensity, and has important applications in laser plasma accelerators. The off-axis design of an axiparabola has the advantage of separating the focus from incident rays. However, an off-axis axiparabola designed by the current method always produces a curved focal line. In this paper, we propose a new method to design its surface by combining geometric optics design and diffraction optics correction, which can effectively convert a curved focal line into a straight foal line. We reveal that the geometric optics design inevitably introduces an inclined wavefront, which leads to the bending of the focal line. To compensate for the tilt wavefront, we use an annealing algorithm to further correct the surface through diffraction integral operation. We also carry out numerical simulation verification based on scalar diffraction theory, which proves that the surface of this off-axis mirror designed by this method can always obtain a straight focal line. This new method has wide applicability in an axiparabola with any off-axis angle.

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