Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Heliyon ; 10(12): e32493, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38975209

RESUMO

This in vitro study was to evaluate the effect of different non-thermal atmospheric pressure plasma (NTP) on shear bond strength (SBS) between yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and self-adhesive resin cement. In this study, The Y-TZP specimens were divided into 4 groups according to the surface treatment methods as follows: Control (no surface treatment), Sb (Sandblasting), AP(argon NTP), and CP(20 % oxygen and 80 % argon combination NTP). Y-TZP specimens were randomly selected from each group to observe and test the following indexes: scanning electron microscope to observe the surface morphology; atomic force microscope to detect the surface roughness; contact angle detector to detect the surface contact angle; energy spectrometer to analyze the surface elements. Then, resin cement (Rely X-U200) was bonded to human isolated teeth with Y-TZP specimens to measure SBS. The results showed that for the SE test, the NTP group was significantly higher than the control group (p < 0.05). The results of the SBS test showed that the SBS values of the NTP group were significantly higher than those of the other groups, regardless of the plasma treatment (p < 0.05). However, there was no significant difference between groups AP and CP in a test of SBS (p > 0.05). This study shows that non-thermal atmospheric pressure plasma can improve the shear bond strength of Y-TZP by increasing the surface energy. The addition of oxygen ratio to argon is more favorable to increase the shear bond strength and is worth further investigation.

2.
Beijing Da Xue Xue Bao Yi Xue Ban ; 56(1): 99-105, 2024 Feb 18.
Artigo em Chinês | MEDLINE | ID: mdl-38318903

RESUMO

OBJECTIVE: To evaluate the sealing ability of GuttaFlow2 single cone obturation in curved root canals. METHODS: (1) Slight, moderate and severe curved 3D printed root canals were made. After instrumentation, these samples were randomly divided into 2 groups (n = 10) according to different root canal filling techniques: GuttaFlow2 single cone group (GF2) and AH-Plus warm vertical compation group (WVC). All the samples were sectioned at 2 mm to apex (the apical of the root), 4 mm, 6 mm to apex (the middle of the root) and 8 mm to apex (the coronal of the root). The filling void areas were observed by stereomicroscope, and the percentages of void areas in each section were calculated by ImageJ 1.52a. (2) Forty-eight roots of extracted adult molars were selected. After instrumentation, they were randomly divided into 2 groups (n = 8): GF2 group and WVC group. Before root canal filling, the sea-lers were mixed with Rhodamine B dye for visualization under confocal laser scanning microscope. All samples were sectioned at 2 mm to apex (the apical of the root), 5 mm to apex (the middle of the root) and 8 mm to apex(the coronal of the root). Then, the percentages of sealer penetration into dentinal tubules in each section were calculated. RESULTS: At the apical of the root, there were no obvious voids in slight, moderate and severe curved canals in the GF2 group and the WVC group. There was no significant difference between the two groups (P > 0.05). At the middle of the root, there was no significant difference in the percentages of void areas between the two filling methods, but at the coronal of the root, there were more voids in the slight curved root canal in the GF2 group than in the WVC group, and the difference was significant (P = 0.009). The percentages of sealer penetration into dentinal tubules of slight, moderate and severe curved root canals in the GF2 group were 36.10%, 55.80%, 65.08%, respectively. And they were all higher than those in the WVC group (15.78%, 20.70%, 15.61%), respectively, the difference between the two groups was significant (P = 0.001). At the middle of the root, the percentages of sealer penetration into dentinal tubules of slight and moderate curved root canals in GF2 group were also significantly higher than those in the WVC group (P = 0.001). At the coronal of the root, there was no significant difference between the two groups (P > 0.05). CONCLUSION: GuttaFlow2 filling technique has the same sealing effect on the root canal at the apical and middle of the root as the warm vertical technique, but has a better sealing effect on the dentin tubules, especially for severe curved root canal.


Assuntos
Materiais Restauradores do Canal Radicular , Cavidade Pulpar , Preparo de Canal Radicular , Tratamento do Canal Radicular , Obturação do Canal Radicular/métodos , Guta-Percha
3.
Phys Med Biol ; 68(17)2023 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-37541223

RESUMO

Objective. Metal artifact reduction (MAR) remains a challenging task due to the difficulty of removing artifacts while preserving anatomical details of the tissue. Although current dual-domain networks have shown promising performance in MAR, they heavily rely on the image domain, which can be too smooth and lose important information in the metal-affected area. To address this problem, we propose an improved dual domain network framework.Approach. We enhance sinogram completion performance by utilizing an aggregated contextual transformations network in the sinogram domain. Furthermore, we utilizea prior-projection-based linearized correction method to obtain images with beam-hardening artifacts removed, which are incorporated into the input of the image post-processing network to assist in training the image domain network. Finally, we train the sinogram domain network and the image domain network separately to their respective convergences.Main results. In experiments conducted on a simulated dataset, our method achieves the best average RMSE of 25.1, SSIM of 0.973, and PSNR of 42.1, respectively.Significance. The proposed method is capable of preserving tissue structures near metallic objects while eliminating metal artifacts from the reconstructed images. Related codes will be released athttps://github.com/Corinna-China/AOTDudoNet.


Assuntos
Processamento de Imagem Assistida por Computador , Tomografia Computadorizada por Raios X , Processamento de Imagem Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Artefatos , Metais , Algoritmos , Imagens de Fantasmas
4.
BMC Endocr Disord ; 22(1): 152, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35668434

RESUMO

BACKGROUND: Cushing's disease (CD) is rare in pediatric patients. It is characterized by elevated plasma adrenocorticotropic hormone (ACTH) from pituitary adenomas, with damage to multiple systems and development. In recent years, genetic studies have shed light on the etiology and several mutations have been identified in patients with CD. CASE PRESENTATION: A girl presented at the age of 10 years and 9 months with facial plethora, hirsutism and acne. Her vision and eye movements were impaired. A quick weight gain and slow growth were also observed. Physical examination revealed central obesity, moon face, buffalo hump, supra-clavicular fat pads and bruising. Her plasma ACTH level ranged between 118 and 151 pg/ml, and sella enhanced MRI showed a giant pituitary tumor of 51.8 × 29.3 × 14.0 mm. Transsphenoidal pituitary debulk adenomectomy was performed and immunohistochemical staining confirmed an ACTH-secreting adenoma. Genetic analysis identified a novel germline GPR101 (p.G169R) and a somatic USP8 (p. S719del) mutation. They were hypothesized to impact tumor growth and function, respectively. CONCLUSIONS: We reported a rare case of pediatric giant pituitary ACTH adenoma and pointed out that unusual concurrent mutations might contribute to its early onset and large volume.


Assuntos
Adenoma Hipofisário Secretor de ACT , Adenoma , Hipersecreção Hipofisária de ACTH , Neoplasias Hipofisárias , Adenoma Hipofisário Secretor de ACT/diagnóstico , Adenoma Hipofisário Secretor de ACT/genética , Adenoma Hipofisário Secretor de ACT/cirurgia , Adenoma/diagnóstico , Adenoma/genética , Adenoma/cirurgia , Hormônio Adrenocorticotrópico , Endopeptidases/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Feminino , Células Germinativas/patologia , Humanos , Mutação , Hipersecreção Hipofisária de ACTH/diagnóstico , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/cirurgia , Receptores Acoplados a Proteínas G , Ubiquitina Tiolesterase/genética
5.
Mol Biotechnol ; 64(11): 1234-1243, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35532870

RESUMO

MiR-99a-5p participates in processes and pathogenesis of varying diseases. However, the molecular mechanism of miR-99a-5p in human cervical squamous cell carcinoma (CSCC) remains unclear. Here, we found that miR-99a-5p was lowly expressed in CSCC cells and negatively associated with overall survival. In addition, cellular experiments including CCK8, wound healing, Transwell and flow cytometry assays disclosed that transfection of miR-99a-5p mimic could suppress the cell activity, cell migratory, and invasive abilities, and promote cell apoptosis, thus inhibiting the tumor progression of CSCC cells. Luciferase reporter gene assay indicated that miR-99a-5p targeted 3'-UTR of CDC25A. Also, enforced CDC25A level rescued the impact of miR-99a-5p on CSCC progression. Silencing CDC25A could restrain the mRNA and protein levels of IL-6 in CSCC. CDC25A overexpression or IL-6 treatment could attenuate inhibiting impact of miR-99a-5p overexpression on epithelial-mesenchymal transition (EMT). These findings suggested that miR-99a-5p may play an anti-tumor role in tumor metastasis by targeting CDC25A/IL6 to hamper EMT process, which revealed a novel molecular mechanism in CSCC.


Assuntos
Carcinoma de Células Escamosas , Transição Epitelial-Mesenquimal , MicroRNAs , Neoplasias do Colo do Útero , Feminino , Humanos , Regiões 3' não Traduzidas , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Fosfatases cdc25/genética , Fosfatases cdc25/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , Interleucina-6/genética , Interleucina-6/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/metabolismo
6.
Am J Med Genet A ; 182(9): 2184-2186, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32706452

RESUMO

Farber disease (FD) is a rare lysosomal storage disorder caused by mutation of the ASAH1 gene. Classic symptoms of FD include subcutaneous nodules, joint pain and hoarseness. Most patients die during childhood. Here we report a 25-year-old female FD patient with rare osteolytic changes of bilateral hands and toes. Genetic analysis revealed novel compound heterozygous mutations in the ASAH1 gene (c.427T>G and c.358G>C). Further research is needed to elucidate the pathophysiological course.


Assuntos
Ceramidase Ácida/genética , Lipogranulomatose de Farber/genética , Predisposição Genética para Doença , Doenças por Armazenamento dos Lisossomos/genética , Adulto , Criança , China , Feminino , Humanos , Doenças por Armazenamento dos Lisossomos/patologia , Mutação
7.
Caries Res ; 51(5): 507-514, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28965113

RESUMO

Previous studies have shown that Streptococcus oligofermentans inhibits the growth of cariogenic Streptococcus mutans in biofilms in vitro and is considered a probiotic candidate for caries prevention. This study aimed to examine the effects of various environmental factors on the competition between S. oligofermentans and S. mutans in a dual-species biofilm model. Single or dual S. oligofermentans and S. mutans biofilms were grown in a 96-well active attachment model for 48 h. Several growth conditions were examined in the model, namely: S. oligofermentans was inoculated 24 h before S. mutans or vice versa; the growth medium was supplemented with 0.2% sucrose or 0.4% glucose; biofilms were grown under a constantly neutral pH or pH-cycling condition, which included 8 h of neutral pH and 16 h of pH 5.5. The 48-h biofilms were examined for viable cell counts and lactic acid and hydrogen peroxide production ability. When S. oligofermentans was inoculated first, it clearly inhibited the growth of S. mutans and reduced the biofilm lactic acid production by up to 8-fold through hydrogen peroxide production, independently of sugar supply and pH conditions. When S. mutans was inoculated first, the level of inhibition by S. oligofermentans varied depending on the sugar supply and pH conditions. Thus, the inhibition efficacy of S. oligofermentans against S. mutans in dual-species biofilms is influenced by environmental factors. This study provides practical information on how to maximize the efficacy of S. oligofermentans.


Assuntos
Antibiose/fisiologia , Biofilmes/crescimento & desenvolvimento , Streptococcus mutans/crescimento & desenvolvimento , Streptococcus mutans/fisiologia , Streptococcus/crescimento & desenvolvimento , Técnicas Bacteriológicas , Contagem de Células , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Ácido Láctico/metabolismo
8.
PLoS One ; 10(6): e0130962, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26114758

RESUMO

Homeostasis of oral microbiota can be maintained through microbial interactions. Previous studies showed that Streptococcus oligofermentans, a non-mutans streptococci frequently isolated from caries-free subjects, inhibited the cariogenic Streptococcus mutans by the production of hydrogen peroxide (HP). Since pH is a critical factor in caries formation, we aimed to study the influence of pH on the competition between S. oligofermentans and S. mutans in biofilms. To this end, S. mutans and S. oligofermentans were inoculated alone or mixed at 1:1 ratio in buffered biofilm medium in a 96-well active attachment model. The single- and dual-species biofilms were grown under either constantly neutral pH or pH-cycling conditions. The latter includes two cycles of 8 h neutral pH and 16 h pH 5.5, used to mimic cariogenic condition. The 48 h biofilms were analysed for the viable cell counts, lactate and HP production. The last two measurements were carried out after incubating the 48 h biofilms in buffers supplemented with 1% glucose (pH 7.0) for 4 h. The results showed that S. oligofermentans inhibited the growth of S. mutans in dual-species biofilms under both tested pH conditions. The lactic acid production of dual-species biofilms was significantly lower than that of single-species S. mutans biofilms. Moreover, dual-species and single-species S. oligofermentans biofilms grown under pH-cycling conditions (with a 16 h low pH period) produced a significantly higher amount of HP than those grown under constantly neutral pH. In conclusion, S. oligofermentans inhibited S. mutans in biofilms not only under neutral pH, but also under pH-cycling conditions, likely through HP production. S. oligofermentans may be a compelling probiotic candidate against caries.


Assuntos
Streptococcus mutans/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Streptococcus/metabolismo
9.
J Endod ; 39(10): 1218-25, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24041381

RESUMO

INTRODUCTION: The aim of this study was to compare the outcome of a root canal treatment with and without additional ultrasonic activation of the irrigant. METHODS: Single-rooted teeth with radiographic evidence of periapical bone loss were randomly assigned to 2 treatment groups. In both groups syringe irrigation was performed, and in one group the irrigant was also activated by ultrasound. Ten to 19 months after treatment, the teeth were examined by using periapical radiography (PA) and cone-beam computed tomography (CBCT). Area and volume of the periapical lesions were measured, and the outcome was presented in 4 categories: absence, reduction or enlargement of the radiolucency, or uncertain. Lesions were classified as reduced or enlarged when the change in size of the radiolucency was 20% or more. RESULTS: The recall rate was 82%, and 84 teeth were analyzed. CBCT detected significantly more post-treatment lesions than PA (P = .038), but the percentages of absence and reduction of the radiolucency together revealed by CBCT and PA were similar (P = .383). The CBCT results showed that absence of the radiolucency was observed in 16 of 84 teeth (19%) and reduction of the radiolucency in 61 of 84 teeth (72.6%), but there was no significant difference between the results of the 2 groups (P = .470). Absence and reduction of the radiolucency together were observed in the ultrasonic group in 39 of 41 teeth (95.1%) and in the syringe group in 38 of 43 teeth (88.4%). CONCLUSIONS: Root canal treatments with and without additional ultrasonic activation of the irrigant contributed equally to periapical healing.


Assuntos
Irrigantes do Canal Radicular/administração & dosagem , Preparo de Canal Radicular/métodos , Tratamento do Canal Radicular/métodos , Adolescente , Adulto , Idoso , Tomografia Computadorizada de Feixe Cônico/métodos , Cavidade Pulpar/diagnóstico por imagem , Cavidade Pulpar/patologia , Ácido Edético/administração & dosagem , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Agulhas , Doenças Periapicais/diagnóstico por imagem , Doenças Periapicais/terapia , Radiografia Interproximal/métodos , Radiografia Dentária Digital/métodos , Materiais Restauradores do Canal Radicular/uso terapêutico , Preparo de Canal Radicular/instrumentação , Hipoclorito de Sódio/administração & dosagem , Seringas , Irrigação Terapêutica/instrumentação , Irrigação Terapêutica/métodos , Resultado do Tratamento , Ultrassom , Cicatrização/fisiologia , Adulto Jovem
10.
Beijing Da Xue Xue Bao Yi Xue Ban ; 44(1): 34-8, 2012 Feb 18.
Artigo em Chinês | MEDLINE | ID: mdl-22353896

RESUMO

OBJECTIVE: To evaluate the disinfection efficacy of MTAD on Enterococcus faecalis biofilm and smear layer colonization in apical isthums of the root canal system. METHODS: Fifteen extracted human maxillary first premolars with isthmus anatomic structure which confirmed by stereo-microscope were contaminated with E. faecalis in vitro and randomly divided into 5 groups: the first group was not treated serving as a baseline control, the second group was treated by normal saline (NS) serving as negative control, the third group was treated by MTAD , the forth group by 5.25% NaOCl, and the fifth group by 5.25% NaOCl + EDTA. All roots in the latter four groups were instrumented by Protaper rotary files and irrigated with respective irrigant, then the roots were split longitudinally and a scanning electron microscope was used to evaluate the antibacterial activity and smear layer cleaning ability of irrigants on isthmus. RESULTS: In the first group, E. faecalis colonized on the isthmus surface and aggregated together to form biofilm-like microorganism community, some bacteria also colonized in the dentinal tubules. When treated with NS, both smear layer and bacteria remained (median of smear layer score was 5). MTAD can remove partial smear layer, and have limited antibacterial activity, some bacteria embedded in smear layer (the median was 3) and were destroyed; In 5.25% NaOCl treatmentgroup, the smear layer was not removed (median of smear layer score was also 5), but all bacteria on the surface were extinguished. The combined use of 5.25% NaOCl and EDTA produced a cleaner isthmus surface and had marked antimicrobial effect, with the median of smear layer score being only 1. CONCLUSION: MTAD may permeate into the isthmus area of apical root canal system, but only performed a partial effect of disinfection and limited antibacterial activity. Sodium hypochlorite cooperated with EDTA can remove infection effectively in the isthmus area.


Assuntos
Ácido Cítrico/farmacologia , Doxiciclina/farmacologia , Periodontite Periapical/microbiologia , Tecido Periapical/ultraestrutura , Polissorbatos/farmacologia , Irrigantes do Canal Radicular/farmacologia , Biofilmes/efeitos dos fármacos , Enterococcus faecalis/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Técnicas In Vitro , Tecido Periapical/microbiologia , Hipoclorito de Sódio/farmacologia
11.
Eur J Radiol ; 80(2): e42-9, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20709478

RESUMO

PURPOSE: Though highly desirable in radiologic procedures, low-dose CT (LDCT) images tend to be severely degraded by quantum noise and non-stationary artifacts. The purpose of this paper is to improve the abdominal LDCT images by the approach of Weighted Intensity Averaging over Large-scale Neighborhoods (WIA-LN). MATERIALS AND METHODS: In the implementation of the proposed WIA-LN method, the processed pixel intensities are adaptively calculated as the weighted intensity averaging of the pixels with similar surrounding structures throughout a large-scale neighborhood. Both phantom and clinical abdominal CT images from a 16 detector rows Siemens CT were acquired at standard and 80% reduced tube current time products (150 mAs and 30 mAs corresponding to standard-dose and low-dose protocols, respectively). Visual comparison, statistical qualitative analysis (image quality scores and hepatic cyst diagnosis), and quantitative calculation (noise and contrast-to-noise ratio) are made. RESULTS: Better vision and quantitative performance are realized using the proposed WIA-LN method. Compared to original LDCT and standard-dose CT (SDCT) images, statistically significant improvement of noise/artifacts suppression, contrast preservation and hepatic cyst detection in LDCT images are achieved by using the proposed method (P<0.05). CONCLUSION: With the tube current reduced to approximate one-fifth of the standard tube current setting, clinically acceptable images can still be obtained by using the proposed method.


Assuntos
Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Radiografia Abdominal/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Artefatos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Razão Sinal-Ruído , Estatísticas não Paramétricas
12.
Chin Med J (Engl) ; 124(21): 3499-503, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22340167

RESUMO

BACKGROUND: Streptococcus (S.) oligofermentans is a newly identified bacteria with a yet to be defined mechanism of sucrose metabolism that results in acid production. This study aimed to investigate the biochemical mechanisms of S. oligoferm-entans glucose metaolism. METHODS: The S. oligofermentans LMG21532, Lactobacillus (L.) fermentum 38 and the S. mutans UA140 were used to characterize sucrose metabolism by measuring lactate dehydrogenase (LDH) activity and lactic acid production. Continuous dynamics and high performance capillary electrophoresis were used to determine LDH activity and lactic acid production, respectively, from bacteria collected at 0, 10 and 30 minutes after cultured in 10% sucrose. RESULTS: These analyses demonstrated that LDH activity of the three bacterial strains examined remained stable but significantly different throughout the sucrose fermentation process. The S. oligofermentans LDH activity ((0.61 ± 0.05) U/mg) was significantly lower than that of L. fermentum ((52.91 ± 8.97) U/mg). In addition, the S. oligofermentans total lactate production ((0.048 ± 0.021) mmol/L) was also significantly lower than that of L. fermentum ((0.958 ± 0.201) mmol/L). Although the S. oligofermentans LDH production was almost double of that produced by S. mutans ((0.32 ± 0.07) U/mg), lactic acid production was approximately one sixth that of S. mutans ((0.296 ± 0.058) mmol/L). Additional tests examining pyruvic acid production (the LDH substrate) demonstrated that lactic acid concentrations correlated with pyruvic acid production. That is, pyruvic acid production by S. oligofermentans was undetectable following sucrose incubation, however, (0.074 ± 0.024) and (0.175 ± 0.098) mmol/L pyruvic acid were produced by S. mutans and L. fermentum, respectively. CONCLUSION: S. oligofermentans is incapable of fermenting carbohydrates to produce enough pyruvic acid, which results in reduced lactic acid production.


Assuntos
Ácido Láctico/metabolismo , Ácido Pirúvico/metabolismo , Streptococcus/metabolismo , Sacarose/metabolismo , L-Lactato Desidrogenase/metabolismo
13.
Artigo em Inglês | MEDLINE | ID: mdl-18003523

RESUMO

Volume reconstruction is one of the key problems in 3D image rendering and analysis. Inter slice interpolation methods have been widely discussed in the literature and object-based algorithms have been shown to well behave. In this paper, we present a non-rigid registration based strategy to improve the volume reconstruction. A level set evolution technique is proposed to yield the deformation between adjacent slices. A modified bilinear interpolation method is then designed to generate propagating image. A multi-resolution scheme is applied to decrease the computation time and support large deformation. The resulting images show good results on regions enclosing different anatomic structures.


Assuntos
Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Encéfalo , Humanos
14.
Zhongguo Yi Liao Qi Xie Za Zhi ; 31(1): 10-3, 2007 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-17432117

RESUMO

In this paper, a low-cost PC-based, high-quality and interactive 3D stereoscopic medical visualization system is presented, which can be clinically used for diagnosis and surgical planning. The algorithms of direct volume rendering have been improved for realization with the programmable graphics hardware under PC environment. Local illumination, classification and non-polygonal iso-surface rendering are also incorporated into the system in appropriate consideration of both high-quality rendering and real-time interaction. The medical visualization system has been applied to the neurosurgical and orthopedic planning and the effectiveness has been clinically proved.


Assuntos
Imageamento Tridimensional , Técnicas de Planejamento , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Procedimentos Neurocirúrgicos , Procedimentos Ortopédicos , Interface Usuário-Computador
15.
Comput Biol Med ; 37(6): 793-804, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17010330

RESUMO

The basic mathematical problem behind PET is an inverse problem. Due to the inherent ill-posedness of this inverse problem, the reconstructed images will have noise and edge artifacts. A roughness penalty is often imposed on the solution to control noise and stabilize the solution, but the difficulty is to avoid the smoothing of edges. In this paper, we propose two new types of Bayesian one-step-late reconstruction approaches which utilize two different prior regularizations: the mean curvature (MC) diffusion function and the Gauss curvature (GC) diffusion function. As they have been studied in image processing for removing noise, these two prior regularizations encourage preserving the edge while the reconstructed images are smoothed. Moreover, the GC constraint can preserve smaller structures which cannot be preserved by MC. The simulation results show that the proposed algorithms outperform the quadratic function and total variation approaches in terms of preserving the edges during emission reconstruction.


Assuntos
Algoritmos , Teorema de Bayes , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Tomografia por Emissão de Pósitrons/estatística & dados numéricos , Humanos , Imagens de Fantasmas
16.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 41(5): 263-5, 2006 May.
Artigo em Chinês | MEDLINE | ID: mdl-16784602

RESUMO

OBJECTIVE: To investigate the buffer capacity of insoluble plaque mass including bacteria and glucans matrix. METHODS: Plaque samples (starved or incubated 1 h with 10% sucrose), Streptococcus mutans (S. mutans) mass, and insoluble/soluble glucans were titrated with 1 mmol/L HCl. Meanwhile, the density of bacteria was counted and related to buffer capacity. RESULTS: The bacteria density had significant effects on acid buffer capacity in dental plaque, but the effect reduced with consuming sugar. S. mutans mass with no sucrose incubating contributed to the buffer capacity of (0.609 +/- 0.202) mmol/L, and S. mutans mass with 2% sucrose had only the buffer capacity of (0.099 +/- 0.047) mmol/L. In the mean time, glucans had no effect on acid buffering (0.028 - 0.032 mmol/L). CONCLUSIONS: The bacteria including S. mutans may be the main contributor to acid buffering in plaque solid.


Assuntos
Placa Dentária/fisiopatologia , Glucanos/metabolismo , Streptococcus mutans/metabolismo , Ácidos , Adolescente , Adulto , Contagem de Colônia Microbiana , Suscetibilidade à Cárie Dentária , Placa Dentária/microbiologia , Feminino , Humanos , Masculino , Adulto Jovem
17.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 23(4): 329-31, 2005 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-16178198

RESUMO

OBJECTIVE: To develop a computer assisted CT scanning system for 3D dental cast measurement and to study its reliability. METHODS: 20 dental stone casts were scanned by helical CT and captured a series digital sliced radiographs of them. The program which was developed by Visual C 6.0 language and run under the Windows surroundings rebuilt the 3D graphics and measured the coordinate of the dental cast. These dental casts were scanned and measured to test the reliability of the system, contrasting with manual measurement. RESULTS: There was no significant difference between 3D CT scanning and manual measurement (P > 0.05). CONCLUSION: The system is a valuable computer assisted system for clinical diagnosis and treatment of malocclusion.


Assuntos
Processamento de Imagem Assistida por Computador , Modelos Dentários , Humanos , Imageamento Tridimensional , Má Oclusão , Reprodutibilidade dos Testes
18.
Zhongguo Yi Liao Qi Xie Za Zhi ; 26(2): 84-7, 2002 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-16104167

RESUMO

We put forward an image rendering system based on pipeline framework for processing and displaying medical images. Compared to original computer graphics algorithms divided into volume rendering and surface rendering, this framework can effectively comprehend methods of computer graphics and image processing, import some new concepts such as vertex buffer, pixel buffer and texture buffer. We implement Shaded Surface Display, Maximum Intensity Projection, Digitally Reconstructed Radiography, Multi planar Reformation, Curved Planar Reformation and Interactive Virtual Endoscopy in our new developed PACS image system.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional , Sistemas de Informação em Radiologia , Sistemas Computacionais , Sistemas Computadorizados de Registros Médicos , Software
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...