Search

Nasopharyngeal Carcinoma (NPC) has distinct TNM stages whose properties and influences on prognosis are not fully understood ...

Dispersive liquid-liquid microextraction (DLLME) is a new sample preparation technique emerging recently. The dispersion of organic extraction solvent at micro-liter level in aqueous samples is the key step in DLLME. The published strategies of dispersion for DLLME are roughly classified into three types in terms of the instruments used and dispersion principles, namely physical dispersion method, in-situ chemical reaction-based dispersion method and new dispersion medium-based dispersion method. The physical dispersion method includes mechanical shaking method, ultrasound/microwave-assisted method and solubility-adjustment method. The in-situ chemical reaction method is referred to the two modes, in which either the dispersed extraction solvent is formed by in-situ chemical reaction or the dispersion of extraction solvent is achieved by the gas generated from chemical reactions. The new dispersion medium-based dispersion method uses some non-volatile substances, such as medium-chain saturated fatty acids, ionic liquid, surfactant and kapok fiber fragments, to substitute the dispersive solvent used in conventional DLLME. A total of 96 relevant literatures are cited in this review and the prospects of DLLME are highlighted.

According to the aging characteristics of composite casing, we have established the composite bushing model of different radius with the ANSYS finite element analysis software, and analyzed the defects in different forms and the action under different mechanical stress. At the same time, we have studied the aging trend of composite casing and compared with the similarities and differences between the aging of composite insulators. The result showed that under the mechanical stress the bigger than the smaller aging deformation was more serious, and the defect forms had no obvious influence on the development of aging. Thus, the composite casing artificial accelerated aging test should increase the role of mechanical force factor, while the composite insulator aging research methods and conclusions should also increase the qualification when applied to silicone rubber composite casing.

Grid-connected inverter topologies and control methods are analyzed and compared on the basis of two non-isolated PV grid-connected inverter circuit topology as 3kVA grid connected PV systems. In this paper, the current control method, the DC bus voltage outer grid current inner loop of the dual closed-loop PI control method. Sampled signal through the system circuit for processing, resulting in a SPWM drive signal to control the conduction of the power devices off the grid current control.

In this paper, according to the induction motor in rotating coordinate system mathematical model, established based on rotor flux oriented vector control model and realized flux linkage and torque decoupling. In order to solve the current high coupling, designed the sliding mode variable structure control algorithm of current controller. Based on the sliding mode variable structure control algorithm achievable conditions and Lyapunov stability theorem, proved that the sliding mode of accessibility and stability, determined the sliding model parameters. The simulation results show that the sliding mode variable structure control of induction motor vector control system, can reduce the torque ripple and the speed overshoot and improve the system parameter perturbation and external disturbance signal robustness.

The grid-connected inverter plays an important role in the photovoltaic power generation systems, the output of the grid current harmonics affect the stability of the grid. The reason of grid inverter output current distortion, a detailed analysis of current waveform control strategy and its effectiveness of the grid-connected inverter harmonic current suppression is introduced based on the d-q coordinates in this paper.

This study aimed to determine and quantitate the mammographic and sonographic characteristics in 13 cases of solid neuroendocrine breast carcinoma (NEBC) and to analyze the association of radiological findings with the clinical and histopathologic findings. The clinical data and imaging findings of 13 female patients with histologically confirmed solid NEBC were reviewed. Imaging data were evaluated by two radiologists for a consensual diagnosis. All patients presented with one palpable mass; only 1 experienced occasional breast pain, and 5 complained of fluid discharge. In 7 patients, the masses were firm and mobile. Regional lymph node metastasis was noted in only 1 patient. For the 10 patients who underwent mammography, 6 had a mass, 1 had clustered small nodules with clustered punctuate microcalcifications, 2 had asymmetric focal density, and 1 had solitary punctuate calcification. Most of the masses had irregular shape with indistinct or microlobulated margins. For the 9 patients who underwent ultrasonography (US), 9 masses were depicted, all of which were hypoechoic, mostly with irregular shape and without acoustic phenomena. Different types of acoustic phenomena were also identified. One patient had developed distant metastases during follow-up. NEBC has a variety of presentations, but it is mostly observed on mammograms as a dense, irregular mass with indistinct or microlobulated margins. Sonographically, it typically presents as an irregular, heterogeneously hypoechoic mass with normal sound transmission. Histories of nipple discharge and calcification observed using imaging are not rare.

Purpose: To evaluate the use of signal intensity index (SII) of skull-base invasion in nasopharyngeal carcinoma (NPC) using magnetic resonance imaging (MRI), select a best cut-off SII value to predict the outcome of NPC. Materials and Methods: One hundred and twenty-two NPC patients (92 men, 30 women) with skull-base invasion were included. All patients underwent MRI, signal intensities on T1-weighted imaging (T1WI) were measured for each invaded site and its contralateral normal counterpart. The SIIs were calculated, receiver operating characteristic curves were constructed. The optimal cut-off values were extracted. The overall survival (OS) rates of 5-year follow-up were performed. Results: Sensitivities for differentiating skull-base invasion from normal contralateral anatomy were 98.9%, 88.5% and 70.0%, and specificities were 98.9%, 96.0% and 74.4%, respectively. There were three cut-off values for differentiating invasion from normal anatomy of skull-base, 49%, 98%, and 60%. Significant difference in OS rates (84.2% vs. 57.1%, p=0.007) was seen for SII threshold values > 60% and those ≤ 60%. Conclusions: The SII might be a useful means of differentiating invasion from normal tissue at the skull-base in NPC. The cut-off value of quantitative SII at the skull-base may aid in monitoring the response to treatment of NPC patients.

BackgroundAlveolar soft part sarcoma (ASPS) is a relatively rare malignant tumor and early diagnosis and appropriate treatment for ASPS are essential for a good prognosis.PurposeTo retrospectively review the clinical presentation and computed tomography (CT) and magnetic resonance imaging (MRI) findings of ASPS so as to improve the accuracy of imaging diagnosis.Material and MethodsFourteen patients with pathologically proven ASPS were enrolled. Their clinical and imaging findings were retrospectively reviewed.ResultsThe median age of the patients was 29 years (range, 13–37 years). Most tumors were located in the soft tissues of the trunk and lower limbs. The median maximal diameter of the masses was 91 mm. Thirteen masses presented with ovoid or irregular shapes. Eleven masses had less clear boundaries. Compared with the adjacent muscles, the masses were isodense or hypodense on CT, hypo-, iso-, or hyperintense on T1-weighted images, and heterogeneous hyperintense on T2-weighted images. Intense enhancement was seen after contrast agent administration, with prominent intra- or peri-tumoral feeders on CT or flow voids on MRI. By the end of the last follow-up, 13 patients had distant metastasis and three patients had local recurrence.ConclusionASPS should be included in the differential diagnosis when a bulky, heterogeneous soft tissue mass in the trunk and the lower limbs with intense enhancement after contrast administration and prominent intra- or peri-tumoral feeders on CT or flow voids on MRI is seen, particularly in young patients.

The criteria for the diagnosis of metastatic retropharyngeal lymph nodes (RLNs) have not yet been resolved and are not included in the current edition of the American Joint Committee on Cancer (AJCC) staging system (seventh edition) for the staging of nasopharyngeal carcinoma (NPC). The aim of this study was to use MRI to identify an RLN size criterion that can accurately predict prognosis in patients with NPC.Eight hundred seventeen patients with newly diagnosed localized NPC were identified. All of the patients underwent MRI before treatment with definitive radiation therapy. All the MRI studies and medical records were reviewed retrospectively. Overall survival (OS), distant metastasis-free survival (DMFS), and local relapse-free survival (LRFS) were assessed using SPSS software (version 17.0).RLN size cutoffs of ≥ 5 mm and of ≥ 6 mm were used. There was no significant difference in OS (p = 0.216), DMFS (p = 0.081), or LRFS (p = 0.067) in patients with RLNs ≥ 5 mm and in those with RLNs5 mm. When 6 mm was used as a size cutoff, significant differences in OS (p = 0.000) and DMFS (p = 0.001) were identified; there was no significant difference observed for LRFS (p = 0.380).A minimum axial RLN diameter of 6 mm was a more accurate prognostic predictor in NPC patients with RLN metastases than 5 mm.

OBJECTIVES: To analyse the clinical and computed tomography (CT) findings related to reactive thymic hyperplasia in order to improve the recognition of this phenomenon and avert over-treatment. METHODS: Fifty-two children with pathologically proven lymphoma developed reactive thymic hyperplasia following chemotherapy, which was confirmed with long-term review and follow-up. The clinical and CT findings of these 52 children were retrospectively analysed. RESULTS: The median follow-up period for the whole study group was 32.9 months. Fifty-one children survived free of disease; 23 of these had been with tumour invasion and the remaining 29 without. The median period from complete remission (CR) of the mediastinal lesions to the date of recurrent mediastinal masses was 8.6 months, which was not statistically significantly different from that of 9.5 months from commencement of treatment to the date of newly developed mediastinal masses (P= 0.495). The median maximal diameters of the recurrent and newly developed mediastinal masses were not significantly different (P= 0.091). All of the 52 cases presented with a single mediastinal mass; 42 masses (42/52, 81%) of those showed trapezoidal or triangular shapes and were well-circumscribed; 10 masses (10/52, 19%) manifested diffuse shapes and were ill-circumscribed. Forty-two masses (42/52, 81%) showed homogeneous density. All of the masses revealed mild enhancement after contrast administration. Forty-two masses (42/52, 81%) slightly displaced and 10 masses (10/52, 19%) partly surrounded adjacent vessels. After long-term follow-up, 42 masses (42/52, 81%) shrank naturally, and 10 (10/52, 19%) remained unchanged. CONCLUSIONS: Reactive thymic hyperplasia can, and often does, occur in children receiving regular chemotherapy for lymphoma, regardless of whether the tumour initially invades the mediastinum. Knowing the characteristic CT findings of this benign entity is helpful in differentiating it from residual or recurrent lymphoma and averting unnecessary treatment.

The purpose of this study is to investigate the incidence, distribution and spread pattern of retropharyngeal lymph node (RLN) metastasis in the patient with nasopharyngeal carcinoma (NPC) using magnetic resonance imaging (MRI).MRI data of 294 patients with newly diagnosed NPC were reviewed retrospectively. Criteria for RLN metastasis were the minimal axial dimension ofor = 6 mm, or the presence of nodal necrosis.RLN involvement was detected in 165 (56.1%) patients. The incidence of metastatic lateral RLN decreased gradually from C1 to C3 level. A significantly higher incidence of metastatic RLN was observed in the patients with cancerous involvement of oropharynx, nasal cavity, pre-styloid parapharyngeal space, post-styloid parapharyngeal space or with cervical lymph node metastasis. Thirty-one patients (10.5%) had metastatic RLN only, and 54 (18.4%) showed metastatic cervical lymph nodes only, but 134 (45.6%) exhibited an involvement of both the RLN and cervical lymph node. A significantly lower incidence of metastatic RLN was found in T1, N0, and stage I disease.The incidence of metastatic lateral retropharyngeal lymph node decreases gradually from C1 to C3 level. Metastatic retropharyngeal lymph node is associated with cancerous involvement of surrounding tissue by primary tumor or with cervical lymph node metastasis. Retropharyngeal lymph node or cervical level II node can be considered equally as the first station of nodal metastasis in nasopharyngeal carcinoma.

Preoperative staging is important for optimal therapy planning and prognosis prediction of rectal carcinoma. The role of conventional computed tomography (CT) in preoperative staging of rectal carcinoma is controversial. This study was to evaluate the value of multislice spiral computed tomography (MSCT) in preoperative staging of rectal carcinoma.From Mar. 2006 to Feb. 2007, 87 patients with pathologically proved rectal cancer underwent preoperative plain and enhanced MSCT. Two radiologists evaluated independently tumor location, size, the depth of tumor invasion into the rectal wall (T), the involvement of regional lymph nodes (N) and the presence of distant metastases (M) on CT images. TNM staging was made according to CT findings and compared with the pathologic results. The accuracy, sensitivity, and specificity were assessed.All the 87 cases of rectal carcinoma were detected clearly by MSCT. The accuracy was 81.6% for TNM staging, 94.3% for T staging, 82.8% for N staging, and 98.9% for M staging. The sensitivity was 90.5% for T1-2 staging, 91.3% for T3 staging, and 97.7% for T4 staging. The specificity was 98.5% for T1-2 staging, 94.2% for T3 staging, and 97.7% for T4 staging. The sensitivity was 92.9% for N0 staging, 72.0% for N1 staging, and 82.4% for N2 staging. The specificity was 88.9% for N0 staging, 88.5% for N1 staging, and 91.7% for N2 staging. Only 1 case of distant metastasis was missed due to the liver lesion of less than 5 mm.MSCT is an accurate technique for preoperative staging of rectal carcinoma, which can assess the extension to adjacent tissues and the presence of lymph node and distant metastases exactly.

To synthesize a novel gadolinium-loaded nanoparticle as a molecular imaging contrast agent for magnetic resonance imaging.Gadolinium ion was incorporated within a silica nanoparticle. The size of this nanosized particle was determined by using transmission electron microscope. The spin-echo (SE) images of nine nanoparticle dilutions in vitro were obtained from a 1.5 T clinical scanner, compared with gadolinium diethylene triaminepenta acetate (Gd-DTPA). In vivo distribution of nanoparticle in Balb/c nude mice and Balb/c nude mice with nasopharyngeal carcinoma (NPC) xenografted CNE-2 tumors was studied at MR imaging, 30 sec, 5 min, 30 min, 1 h, 2 h, 4 h, and 24 h after intravenous administration.The gadolinium-loaded nanoparticle was short rod-shaped, and approximately 30 to 40 nm in diameter. The value of longitudinal relaxativity (r(1)) of gadolinium nanoparticle was much higher than that of Gd-DTPA. Thirty minutes after injection the gadolinium nanoparticle, the signal intensities of liver, kidney and xenografted tumor increased from 226 +/- 10, 283 +/- 7 and 195 +/- 5 to 352 +/- 12, 328 +/- 10 and 245 +/- 7, respectively. The dynamic MRI scanning showed that gadolinium nanoparticles were mainly distributed in liver after intravenous administration. Strong enhancement was also detected in CNE-2 xenografted tumors.A new gadolinium-loaded nanoparticle with high relaxativity was synthesized successfully, and might serve as a carrier for magnetic resonance molecular imaging.