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1.
Opt Express ; 32(7): 11150-11170, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38570970

RESUMEN

The magnetorheological finishing (MRF) of surfaces often results in tool mark errors. A prediction model can effectively guide subsequent processing, necessitating thorough research. To address this issue, this paper introduces an enhanced continuous tool influence function method. This method involves sub dwell time convolution with varying tool influence functions, enabling tool mark prediction. Numerical simulations demonstrate the proposed method's effectiveness, while the data size is estimated to confirm its economic properties. Subsequently, a MRF experiment was conducted, affirming the practicability through power spectral density evaluation. A fast algorithm is given to guide tool mark predictions on large-aperture mirrors fabrication engineering subjected to sub-aperture polishing.

2.
Opt Express ; 32(7): 11241-11258, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38570976

RESUMEN

Scratches on optical components induce laser damage and limit the increase in laser power. Magnetorheological finishing (MRF) is a highly deterministic optical manufacturing technology that can improve the surface roughness of optical components. Although MRF has exhibited significant potential for reducing subsurface damage and removing scratches, the principle and mechanism behind the scratch removal are not sufficiently understood. In this study, the theory of fluid mechanics is used to analyze the pressure, velocity, and particle trajectory distribution near a scratch. A physical model was developed for the differential removal of scratches at the bottom and surface of the optical components. The morphological evolution of the scratch was predicted during removal, and detailed experiments were performed to verify the effectiveness of the proposed model. The results indicate that scratches expand laterally rather than being completely removed. Furthermore, scratch removal efficiency is greater when the removal direction is perpendicular to the scratch rather than being parallel. This study offers an intrinsic perspective for a comprehensive understanding of the MRF technique used for scratch removal, which can be beneficial for removing scratches from aspherical optical systems.

3.
Appl Opt ; 63(15): 4024-4031, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38856494

RESUMEN

More accurate dwell time calculation methods are necessary to achieve superior error convergence in producing optically critical components. Although the discrete convolution matrix method finds widespread application, it still has approximate errors in the non-uniform discrete form of tool paths. To address this issue, this paper introduced a modified matrix elements method and presented the general Voronoi polygon area weight calculation forms under different tool path discretization forms. The mechanism is explained through analysis and the validity is verified by numerical simulation. The modified method significantly improved uniformity distribution and accuracy in computation of surface residuals. This improvement holds promise as a guiding principle for the fabrication of ultra-precision optical components.

4.
J Xray Sci Technol ; 32(4): 1137-1150, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38875073

RESUMEN

BACKGROUND: The polychromatic X-rays generated by a linear accelerator (Linac) often result in noticeable hardening artifacts in images, posing a significant challenge to accurate defect identification. To address this issue, a simple yet effective approach is to introduce filters at the radiation source outlet. However, current methods are often empirical, lacking scientifically sound metrics. OBJECTIVE: This study introduces an innovative filter design method that optimizes filter performance by balancing the impact of ray intensity and energy on image quality. MATERIALS AND METHODS: Firstly, different spectra under various materials and thicknesses of filters were obtained using GEometry ANd Tracking (Geant4) simulation. Subsequently, these spectra and their corresponding incident photon counts were used as input sources to generate different reconstructed images. By comprehensively comparing the intensity differences and noise in images of defective and non-defective regions, along with considering hardening indicators, the optimal filter was determined. RESULTS: The optimized filter was applied to a Linac-based X-ray computed tomography (CT) detection system designed for identifying defects in graphite materials within high-temperature gas-cooled reactor (HTR), with defect dimensions of 2 mm. After adding the filter, the hardening effect reduced by 22%, and the Defect Contrast Index (DCI) reached 3.226. CONCLUSION: The filter designed based on the parameters of Average Difference (AD) and Defect Contrast Index (DCI) can effectively improve the quality of defect images.


Asunto(s)
Diseño de Equipo , Aceleradores de Partículas , Tomografía Computarizada por Rayos X , Tomografía Computarizada por Rayos X/métodos , Tomografía Computarizada por Rayos X/instrumentación , Procesamiento de Imagen Asistido por Computador/métodos , Fantasmas de Imagen , Artefactos
5.
PLoS One ; 19(7): e0307205, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39037979

RESUMEN

BACKGROUND: Diabetic foot ulcers (DFUs), a serious complication of diabetes, are associated with abnormal extracellular protein (EP) metabolism. The identification of key EPs and their regulatory networks is crucial for the understanding of DFU formation and development of effective treatments. In this study, a large-scale bioinformatics analysis was conducted to identify potential therapeutic targets and experimental validation was performed to ensure the reliability and biological relevance of the findings. METHODS: Due to the comprehensive profiling of DFU samples provided by the GSE80178 dataset, we initially selected it to derive differentially expressed genes (DEGs) associated with DFU. Subsequently, utilizing the UniProt database and annotated EP list from the Human Protein Atlas annotation database, we screened for extracellular protein-related differentially expressed genes (EP-DEGs) due to their crucial role in the pathogenesis and healing of DFU. We examined EP-DEG pathway enrichment and protein-protein interaction networks, analyzed paired full-thickness skin tissue samples from 24 patients with DFUs and healthy controls, and performed polymerase chain reaction (PCR) experiments to validate candidate genes. Ultimately, we constructed a transcription factor (TF)-microRNA (miRNA)-hub gene co-regulatory network to explore upstream and downstream regulatory connections based on validated DEGs. RESULTS: Four crucial candidate genes (FMOD, LUM, VCAN, and S100A12) were identified and verified via PCR analysis. The TF-miRNA-hub EP-DEG regulatory network contained the pivotal TFs TRIM28 and STAT3 and the miRNAs hsa-mir-20a-5p, hsa-miR-21, and hsa-miR-203. CONCLUSION: The findings of this study advance our understanding of the pathology of DFU by defining key roles of specific EPs and elucidating a comprehensive regulatory network. These insights pave the way for novel approaches to improve DFU treatment outcomes.


Asunto(s)
Biología Computacional , Pie Diabético , Redes Reguladoras de Genes , MicroARNs , Mapas de Interacción de Proteínas , Humanos , Pie Diabético/genética , Pie Diabético/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Biología Computacional/métodos , Mapas de Interacción de Proteínas/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Perfilación de la Expresión Génica , Masculino , Femenino
6.
Front Pharmacol ; 15: 1337057, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38327989

RESUMEN

Introduction: Hepatic steatosis is a hepatic pathological change closely associated with metabolic disorders, commonly observed in various metabolic diseases such as metabolic syndrome (MetS), with a high global prevalence. Dai-Zong-Fang (DZF), a traditional Chinese herbal formula, is widely used in clinical treatment for MetS, exhibiting multifaceted effects in reducing obesity and regulating blood glucose and lipids. This study aims to explore the mechanism by which DZF modulates the gut microbiota and reduces hepatic steatosis based on the gut-liver axis. Methods: This study utilized db/db mice as a disease model for drug intervention. Body weight and fasting blood glucose were monitored. Serum lipid and transaminase levels were measured. Insulin tolerance test was conducted to assess insulin sensitivity. Hematoxylin and eosin (HE) staining was employed to observe morphological changes in the liver and intestine. The degree of hepatic steatosis was evaluated through Oil Red O staining and hepatic lipid determination. Changes in gut microbiota were assessed using 16S rRNA gene sequencing. Serum lipopolysaccharide (LPS) levels were measured by ELISA. The expression levels of intestinal tight junction proteins, intestinal lipid absorption-related proteins, and key proteins in hepatic lipid metabolism were examined through Western blot and RT-qPCR. Results: After DZF intervention, there was a decrease in body weight, alleviation of glucose and lipid metabolism disorders, reduction in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, and mitigation of insulin resistance in mice. DZF significantly modulated the diversity of the gut microbiota, with a notable increase in the abundance of the Bacteroidetes phylum. PICRUSt indicated that DZF influenced various functions in gut microbiota, including carbohydrate and amino acid metabolism. Following DZF intervention, serum LPS levels decreased, intestinal pathological damage was reduced, and the expression of intestinal tight junction protein occludin was increased, while the expression of intestinal lipid absorption-related proteins cluster of differentiation 36 (CD36) and apolipoprotein B48 (ApoB48) were decreased. In the liver, DZF intervention resulted in a reduction in hepatic steatosis and lipid droplets, accompanied by a decrease fatty acid synthase (FASN) and stearoyl-CoA desaturase 1 (SCD1) and fatty acid transport protein 2 (FATP2). Conversely, there was an increase in the expression of the fatty acid oxidation-related enzyme carnitine palmitoyltransferase-1𝛂 (CPT-1𝛂). Conclusion: DZF can regulate the structure and function of the intestinal microbiota in db/db mice. This ameliorates intestinal barrier damage and the detrimental effects of endotoxemia on hepatic metabolism. DZF not only inhibits intestinal lipid absorption but also improves hepatic lipid metabolism from various aspects, including de novo lipogenesis, fatty acid uptake, and fatty acid oxidation. This suggests that DZF may act on the liver and intestine as target organs, exerting its effects by improving the intestinal microbiota and related barrier and lipid absorption functions, ultimately ameliorating hepatic steatosis and enhancing overall glucose and lipid metabolism.

7.
Sci Rep ; 14(1): 687, 2024 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-38182723

RESUMEN

This study aims to investigate the feasibility and efficacy of anterior atlantoaxial motion preservation fixation (AMPF) in treating axis complex fractures involving the odontoid process fracture and Hangman's fractures with C2/3 instability. A retrospective study was conducted on eight patients who underwent AMPF for axis complex fractures at the General Hospital of Central Theater Command from February 2004 to October 2021. The types of axis injuries, reasons for injuries, surgery time, intraoperative blood loss, spinal cord injury classification (American Spinal Injury Association, ASIA), as well as complications and technical notes, were documented. This study included eight cases of type II Hangman's fracture, five cases of type II and three cases of type III odontoid process fracture. Five patients experienced traffic accidents, while three patients experienced falling injuries. All patients underwent AMPF surgery with an average intraoperative blood loss of 288.75 mL and a duration of 174.5 min. Two patients experienced dysphagia 1 month after surgery. The patients were followed up for an average of 15.63 months. One case improved from C to E in terms of neurological condition, three cases improved from D to E, and four cases remained at E. Bony fusion and Atlantoaxial Motion Preservation were successfully achieved for all eight patients. AMPF is a feasible and effective way for simultaneous odontoid process fracture and Hangman's fractures with C2/3 instability, while preserving atlantoaxial movement.


Asunto(s)
Fracturas Óseas , Apófisis Odontoides , Humanos , Pérdida de Sangre Quirúrgica , Apófisis Odontoides/cirugía , Estudios Retrospectivos , Movimiento (Física)
8.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 38(1): 28-34, 2024 Jan 15.
Artículo en Zh | MEDLINE | ID: mdl-38225837

RESUMEN

Objective: To compare the effectiveness of O-arm navigation and C-arm navigation for guiding percutaneous long sacroiliac screws in treatment of Denis type Ⅱ sacral fractures. Methods: A retrospective study was conducted on clinical data of the 46 patients with Denis type Ⅱ sacral fractures between April 2021 and October 2022. Among them, 19 patients underwent O-arm navigation assisted percutaneous long sacroiliac screw fixation (O-arm navigation group), and 27 patients underwent C-arm navigation assisted percutaneous long sacroiliac screw fixation (C-arm navigation group). There was no significant difference in gender, age, causes of injuries, Tile classification of pelvic fractures, combined injury, the interval from injury to operation between the two groups ( P>0.05). The intraoperative preparation time, the placement time of each screw, the fluoroscopy time of each screw during placement, screw position accuracy, the quality of fracture reduction, and fracture healing time were recorded and compared, postoperative complications were observed. Pelvic function was evaluated by Majeed score at last follow-up. Results: All operations were completed successfully, and all incisions healed by first intention. Compared to the C-arm navigation group, the O-arm navigation group had shorter intraoperative preparation time, placement time of each screw, and fluoroscopy time, with significant differences ( P<0.05). There was no significant difference in screw position accuracy and the quality of fracture reduction ( P>0.05). There was no nerve or vascular injury during screw placed in the two groups. All patients in both groups were followed up, with the follow-up time of 6-21 months (mean, 12.0 months). Imaging re-examination showed that both groups achieved bony healing, and there was no significant difference in fracture healing time between the two groups ( P>0.05). During follow-up, there was no postoperative complications, such as screw loosening and breaking or loss of fracture reduction. At last follow-up, there was no significant difference in pelvic function between the two groups ( P>0.05). Conclusion: Compared with the C-arm navigation, the O-arm navigation assisted percutaneous long sacroiliac screws for the treatment of Denis typeⅡsacral fractures can significantly shorten the intraoperative preparation time, screw placement time, and fluoroscopy time, improve the accuracy of screw placement, and obtain clearer navigation images.


Asunto(s)
Fracturas Óseas , Traumatismos del Cuello , Huesos Pélvicos , Fracturas de la Columna Vertebral , Cirugía Asistida por Computador , Humanos , Fijación Interna de Fracturas/métodos , Estudios Retrospectivos , Imagenología Tridimensional , Tornillos Óseos , Tomografía Computarizada por Rayos X , Fracturas de la Columna Vertebral/cirugía , Fracturas Óseas/cirugía , Huesos Pélvicos/cirugía , Huesos Pélvicos/lesiones , Complicaciones Posoperatorias
9.
Cell Stem Cell ; 2024 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-39096904

RESUMEN

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal fibrotic disease. Recent studies have highlighted the persistence of an intermediate state of alveolar stem cells in IPF lungs. In this study, we discovered a close correlation between the distribution pattern of intermediate alveolar stem cells and the progression of fibrotic changes. We showed that amphiregulin (AREG) expression is significantly elevated in intermediate alveolar stem cells of mouse fibrotic lungs and IPF patients. High levels of serum AREG correlate significantly with profound deteriorations in lung function in IPF patients. We demonstrated that AREG in alveolar stem cells is both required and sufficient for activating EGFR in fibroblasts, thereby driving lung fibrosis. Moreover, pharmacological inhibition of AREG using a neutralizing antibody effectively blocked the initiation and progression of lung fibrosis in mice. Our study underscores the therapeutic potential of anti-AREG antibodies in attenuating IPF progression, offering a promising strategy for treating fibrotic diseases.

11.
Clinics ; 68(7): 1028-1033, jul. 2013. tab
Artículo en Inglés | LILACS | ID: lil-680695

RESUMEN

OBJECTIVE: The acetabular buttress-plate has been widely used in treating difficult cases with satisfying clinical results. However, the biomechanical properties of a postoperative acetabular fracture fixed by the buttress-plate are not clear. The purpose of this study was to evaluate the biomechanical properties of stability after the anterior tube buttress-plate fixation of complex acetabular fractures in the quadrilateral area. METHODS: A construct was proposed based on anterior construct plate - 1/3 tube buttress plate fixation for acetabular both-column fractures. Two groups of six formalin-preserved cadaveric pelvises were analyzed: (1) group A, the normal pelvis and (2) group B, anterior construct plate-1/3 tube buttress plate with quadrilateral area fixation. The displacements were measured, and cyclical loads were applied in both standing and sitting simulations. RESULTS: As the load was added, the displacements were A<B, increasing in line. In the 600 N physiological loading, the differences were significant (standing position: p = 0.013; sitting position: p = 0.009) between groups A and B. CONCLUSION: The anterior construct plate - 1/3 tube buttress plate fixation provided a better stable construct for early sitting. The standing mode yielded more significant differences between the groups. Placing a 1/3 tube buttress-plate via an anterior approach is a novel method of providing quadrilateral area support in this setting. .


Asunto(s)
Humanos , Acetábulo/lesiones , Placas Óseas , Fijación Interna de Fracturas/métodos , Fracturas Óseas/cirugía , Análisis de Varianza , Fenómenos Biomecánicos , Luxaciones Articulares , Valores de Referencia , Reproducibilidad de los Resultados
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