Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 14 de 14
Filter
Add more filters










Publication year range
1.
Chem Commun (Camb) ; 59(79): 11871-11874, 2023 Oct 04.
Article in English | MEDLINE | ID: mdl-37723944

ABSTRACT

The high-density amorphous phases (HDAs) of bimetallic zeolitic imidazolate frameworks (Zn/Co-ZIF-4) were prepared. The temperature dependence of the isobaric heat capacity (Cp) of ZIF-4 HDAs was measured to determine the glass transition temperature (Tg) of HDAs. The Tg non-linearly decreases with the molar ratio R, where R is Co/(Co + Zn), indicating the presence of a mixed-metal node effect. This effect arises from the non-linear increase of the degree of configurational freedom in the HDA as R increases. The degree of configurational freedom is inversely correlated with the network connectivity, which is, in turn, affected by variations in the MN4 (M: Zn or Co; N: nitrogen) tetrahedral symmetry in the ZIF-4 HDA. Overall, this work offers valuable insights into the glass transition of metal-organic frameworks.

2.
Nanoscale ; 10(7): 3429-3437, 2018 Feb 15.
Article in English | MEDLINE | ID: mdl-29393324

ABSTRACT

All-inorganic metal halide perovskites of the formulation ABX3 (where A is Cs+, B is commonly Pb2+, and X is a halide, X = Cl, Br, I) have been studied intensively for their unique properties. Most of the current studies focus on halogen exchange to modify the luminescence band gap. Herein we demonstrate a new avenue for changing the band gap of halide perovskites by designing mixed-monovalent cation perovskite-based colloidal quantum dot materials. We have synthesized monodisperse colloidal quantum dots of all-inorganic rubidium-cesium lead halide perovskites (APbBr3, A = mixed monovalent cation systems Rb/Cs) using inexpensive commercial precursors. Through the compositional modulation, the band gap and emission spectra are readily tunable over the visible spectral range of 474-532 nm. The photoluminescence (PL) of RbxCs1-xPbBr3 nanocrystals is characterized with excellent (NTCS color standard) wide color gamut coverage, which is similar to the cesium lead halide perovskites (CsPbX3, X = mixed halide systems Cl/Br), and narrow emission line-widths of 27-34 nm. Furthermore, simulated lattice models and band structures are used to explain the band gap variations.

3.
Sci Rep ; 7(1): 6518, 2017 07 26.
Article in English | MEDLINE | ID: mdl-28747698

ABSTRACT

Transparent oxyfluoride glasses with highly efficient up-energy conversion (UEC) luminescence were developed in the 45SiO2-15Al2O3-12Na2CO3-21BaF2-7LaF3-xTbF3-yTmF3-zYbF3 composition (in mol%), and structural investigation by X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of face-centered cubic Ba2LaF7 nanocrystals. The colors of UEC luminescences could be tuned easily by adjusting the concentration of doped rare earth ions and the excitation power of laser simultaneously. The relationship between the emission intensity of Tb3+/Tm3+/Yb3+ co-doped oxyfluoride glass-ceramics and the excitation pump power revealed that three-photon and two-photon absorptions predominated in the conversion process from the infrared into blue and red luminescences, respectively. A novel UEC mechanism of red emission from Tm3+ was proposed, energy transfers from Yb3+ to Tm3+ and Tb3+ and from Tm3+ to Tb3+ were evidenced. The possible mechanism responsible for the color variation of UEC in Tb3+/Tm3+/Yb3+ co-doped was discussed.

4.
PLoS One ; 11(7): e0158492, 2016.
Article in English | MEDLINE | ID: mdl-27467703

ABSTRACT

The purpose of this work is to investigate the accurate trajectory tracking control of a wheeled mobile robot (WMR) based on the slip model prediction. Generally, a nonholonomic WMR may increase the slippage risk, when traveling on outdoor unstructured terrain (such as longitudinal and lateral slippage of wheels). In order to control a WMR stably and accurately under the effect of slippage, an unscented Kalman filter and neural networks (NNs) are applied to estimate the slip model in real time. This method exploits the model approximating capabilities of nonlinear state-space NN, and the unscented Kalman filter is used to train NN's weights online. The slip parameters can be estimated and used to predict the time series of deviation velocity, which can be used to compensate control inputs of a WMR. The results of numerical simulation show that the desired trajectory tracking control can be performed by predicting the nonlinear slip model.


Subject(s)
Models, Theoretical , Neural Networks, Computer , Robotics
5.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 37(6): 715-9, 2015 Dec.
Article in Chinese | MEDLINE | ID: mdl-26725396

ABSTRACT

OBJECTIVE: To evaluate the high-resolution and color Doppler ultrasonographic (US) characteristics of cervical lymphadenopathy in patients with infectious mononucleosis. METHODS: High-resolution and color Doppler US were performed in 30 patients aged 2 to 30 years with a total of 59 palpable enlarged cervical lymph nodes due to infectious mononucleosis. The US characteristics of the nodes including shape,echotexture,hilum,border,matting,cystic necrosis,calcification and vascular pattern were assessed. Three patients received cervical lymph nodes biopsies. RESULTS: The common US findings of cervical lymphadenopathy due to infectious mononucleosis were round shape (69.5%),bilateral distribution (96.7%),matting (83.3%) [even bilateral matting (66.6%)],indistinct margin (79.7%),absence of hilum (66.1%),heterogeneous echotecture (61.0%),and central hilar vascular pattern(89.8%). In 2 patients with absence of the echoic hilum,lymph nodes biopsies showed histological features including marked effacement of the normal architecture in the medullary region accompanied by a mixed proliferation of lymphocytes and histiocytes. In all infectious mononucleosis nodes with a hilum,85.0% had heterogeneously hypo/iso-echoic hila and indistinct demarcation to the cortex. One of them underwent lymph node biopsy and histological findings showed obvious dilation of the sinus oidal lumen and proliferation of histiocytes. CONCLUSION: Although several ultrasonographic characteristics frequently present in the nodes of infectious mononucleosis are not specific,the combination of ultrasound findings may be valuable in differential diagnosis.


Subject(s)
Infectious Mononucleosis , Lymphatic Diseases/diagnostic imaging , Neck , Adolescent , Adult , Calcinosis , Child , Child, Preschool , Diagnosis, Differential , Humans , Ultrasonography , Young Adult
6.
Zhonghua Nan Ke Xue ; 20(1): 10-3, 2014 Jan.
Article in Chinese | MEDLINE | ID: mdl-24527530

ABSTRACT

OBJECTIVE: To investigate the effect of transrectal ultrasound-guided microwave ablation of canine prostate tissue. METHODS: Guided by transrectal ultrasound, we conducted microwave ablation on each side of the prostate in 12 male dogs, 6 at 40 W/ 120 s (group A) and the other 6 at 40 W/160 s (group B), and observed the changes in the thermal lesions using grayscale ultrasound. After thermal ablation, we measured the volume of the thermal lesions by contrast-enhanced ultrasound (CEUS). Then we harvested the whole prostate from the animals and determined the lesion volumes in the fresh tissue specimens. RESULTS: Grayscale ultrasound revealed an echogenic area at the initiation of the microwave ablation procedure, which was enlarged with the increase of ablation time. At the end of the procedure, the lesions appeared as an irregular heterogeneous echogenic area. CEUS showed oval non-perfused areas, which appeared as well-defined non-echoic areas in sharp contrast with the surrounding normal prostate parenchyma with bolus injection of contrast material (Sonovue, 2.4 ml), and that the thermal lesion volumes of groups A and B were (1.18 +/- 0.23) cm3 and (1.52 +/- 0.23) cm3, respectively. The thermal lesions of the gross specimen exhibited an elliptical shape, pale color and clear margin, and their volumes were (1.13 +/- 0.20) cm3 and (1.48 +/- 0.20) cm3, respectively, in groups A and B. CONCLUSION: Different combinations of time and power can produce coagulative necrotic lesions of different volumes in the local prostatic tissue. CEUS can accurately manifest the lesion area and thus avoid excessive or inadequate ablation treatment.


Subject(s)
Catheter Ablation/methods , Microwaves/therapeutic use , Prostate/diagnostic imaging , Animals , Dogs , Male , Ultrasonography
7.
Ultrasound Med Biol ; 40(2): 287-92, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24315390

ABSTRACT

The aim of this study was to evaluate the use of gray-level quantification (GLQ) in virtual touch tissue imaging (VTI) in the differential diagnosis of breast lesions. GLQ values of 153 lesions (101 benign, 52 malignant) were analyzed with matrix laboratory software (MATLAB, The MathWorks, Natick, MA, USA), with gray levels ranging from 0 (pure black) to 255 (pure white). The diagnostic performance of GLQ was also evaluated using receiver operating characteristic curve analysis. The mean GLQ value for benign lesions (103.27 ± 39.44) differed significantly from that for malignant lesions (44.57 ± 13.61) (p < 0.001). At a cutoff value of 52.31, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 86.5%, 93.1%, 90.8%, 86.5% and 93.1%, respectively. In conclusion, we have proposed a method for quantification of gray levels in VTI for the differential diagnosis of breast lesions. Our results indicate that this method has the potential to aid in the classification of benign and malignant breast masses.


Subject(s)
Algorithms , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/physiopathology , Elasticity Imaging Techniques/methods , Image Interpretation, Computer-Assisted/methods , Mammography/methods , Adult , Aged , Diagnosis, Differential , Elastic Modulus , Female , Hardness , Humans , Image Enhancement/methods , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Young Adult
8.
Tumour Biol ; 35(1): 111-6, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23888319

ABSTRACT

Recent population studies provide clues that the use of curcumin may be associated with reduced incidence and improved prognosis of certain cancers. In the present study, we demonstrated that curcumin acted as a growth inhibitor for lung cancer cells. Our results found that curcumin inhibited cell proliferation, which was associated with upregulation of the cyclin-dependent kinase inhibitors, p27 and p21, and downregulation of cyclin D1. In addition, we showed that curcumin induced the expression of forkhead box protein O1 (FOXO1) through activation of extracellular signal-regulated kinase 1/2 signaling. These findings provide evidence for a mechanism that may contribute to the antineoplastic effects of curcumin and justify further work to explore potential roles for activators of FOXO1 in the prevention and treatment of lung cancer.


Subject(s)
Antineoplastic Agents/pharmacology , Curcumin/pharmacology , Forkhead Transcription Factors/genetics , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Cell Line, Tumor , Cell Proliferation/drug effects , Cyclin D1/genetics , Cyclin D1/metabolism , Cyclin-Dependent Kinase Inhibitor p21/genetics , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Cyclin-Dependent Kinase Inhibitor p27/genetics , Cyclin-Dependent Kinase Inhibitor p27/metabolism , Disease Progression , Dose-Response Relationship, Drug , Forkhead Box Protein O1 , Forkhead Transcription Factors/metabolism , Humans , MAP Kinase Signaling System/drug effects , Neoplasm Metastasis
9.
Zhonghua Nan Ke Xue ; 17(9): 813-6, 2011 Sep.
Article in Chinese | MEDLINE | ID: mdl-21961243

ABSTRACT

OBJECTIVE: To investigate the feasibility and safety of ultrasound-guided transrectal microwave ablation in reducing the prostate volume. METHODS: Ultrasound-guided transrectal microwave ablation of both sides of the prostate was conducted on experimental dogs with the output volume of 30W for 120 seconds. The dogs were sacrificed on the very day of the ablation, and the prostate and its surrounding tissues were excised for observation of the thermal lesions and pathological examination. RESULTS: A total of 12 thermal lesions were achieved on the two sides of the prostate. The ultrasonogram manifested dense echo and increasing extent in the ablated area, and then an irregular heterogeneous echogenic area and clearly differentiated margin. Pathological examination of the gross specimen showed a little stagnant blood under the rectal mucous, the urethra and bladder not injured, and the thermal lesions elliptical, clearly margined and with the mean size of (0.94 +/- 0.30) cm3. CONCLUSION: Ultrasound-guided transrectal microwave ablation of the prostate can effectively cause coagulative necrosis of the local tissue without inflicting thermal injury upon the surrounding tissues. Conventional grayscale ultrasound can give a real-time'display of the extent of thermal lesion and the whole process of the ablation.


Subject(s)
Catheter Ablation/methods , Prostate/diagnostic imaging , Rectum/diagnostic imaging , Animals , Catheter Ablation/instrumentation , Dogs , Feasibility Studies , Male , Microwaves , Ultrasonography
10.
Int J Hyperthermia ; 27(5): 510-6, 2011.
Article in English | MEDLINE | ID: mdl-21756048

ABSTRACT

OBJECTIVE: The aim of this study was to assess the feasibility, safety and therapeutic effects of ultrasound (US)-guided percutaneous microwave thermal ablation (PMTA) in situ for the treatment of symptomatic uterine fibroid. MATERIALS AND METHODS: The microwave (MW) antenna was percutaneously inserted into the fibroid under US guidance to perform the ablation. The ultrasound images, any complications and side effects were assessed during and after ablation. The shrinkage rate of the fibroid was calculated after the treatment. RESULTS: Forty patients underwent the treatment. The baseline fibroid volume was 14.6 to 341.1 cm(3) (mean 140.1 ± 87.4 cm(3)). When the MW therapy started, a heightened echo around the MW emission aperture of the antenna was observed and gradually propagated throughout the fibroid while the ablation continued. The mean ablation time was 490 s. Contrast enhanced MRI showed no enhancement in the fibroid post-ablation. The shrinkage rate of the fibroid was 61.8%, 78.7%, 73.2% and 93.1% at 3, 6, 9, and 12 months after ablation, respectively. Six patients felt pain in their lower abdomens or waists within 12 hours post-ablation, and the discomfort rapidly disappeared. Seven patients had a small amount of vaginal bloody secretions within one to two weeks after treatment, and six of these patients recovered from the bleeding without any therapy after one week. No patient developed complications and fever during or after the ablation. CONCLUSIONS: PMTA for fibroid is feasible and safe, and it is an easy and fast procedure that is minimally invasive.


Subject(s)
Catheter Ablation/methods , Leiomyoma/surgery , Microwaves/therapeutic use , Uterine Neoplasms/surgery , Adult , Female , Humans , Leiomyoma/diagnostic imaging , Middle Aged , Treatment Outcome , Ultrasonography, Interventional , Uterine Neoplasms/diagnostic imaging
11.
Zhonghua Gan Zang Bing Za Zhi ; 19(5): 352-5, 2011 May.
Article in Chinese | MEDLINE | ID: mdl-21645443

ABSTRACT

OBJECTIVE: To explore the effects of percutaneous transhepatic radiofrequency ablation (PRFA) combined with tumor edge of percutaneous absolute ethanol injection (PEI) on liver cancer adjacent to major blood vessels. METHODS: Seventy five patients with liver cancer adjacent to major blood vessels were randomly divided into two groups: PRFA+PEI therapy group (38 cases) and PRFA control group (37 cases). Tumor necrosis rate, AFP levels, local recurrence rate, median for survival time and cum survival were used as the evaluation index to evaluate the efficacies of the two methods. RESULTS: Tumor necrosis rates of the therapy group and the control group were 84.2% and 54.1% (P < 0.01), respectively; AFP levels of therapy group and control group at 1, 3, 6 and 12 months after treatment were (105.0 ± 35.5) µg/L, (28.4 ± 4.3) µg/L, (58.6 ± 6.7) µg/L, (89.5 ± 12.5) µg/L and (137.2 ± 34.6) µg/L, (84.2 ± 18.4) µg/L, (106.6 ± 20.3) µg/L, (173.7 ± 32.0) µg/L, respectively. The rates of therapy group was significantly lower than of control group. Local recurrence rates of the therapy group and control group were 2.6%, 7.9%, 13.2% and 31.6% vs 10.8%, 21.6% , 40.5% and 62.1% (P < 0.05) at 3, 6, 12 and 24 months after treatment, respectively. Median for survival time of the therapy group and control group were 28.0 ± 2.8 months and 19.0 ± 3.6 months, respectively. Cum survival of the therapy group and control group were 84.2%, 78.9%, 60.5% and 31.6% vs 78.4%, 67.6%, 37.8% and 8.1% (P < 0.05) at 6, 12, 24 and 36 months after treatment, respectively. CONCLUSION: PEI as a supplementary treatment of PRFA can effectively improve the treatment of liver cancer adjacent to major blood vessels and significantly reduce the local recurrence rate and improve long-term survival rates.


Subject(s)
Carcinoma, Hepatocellular/therapy , Catheter Ablation , Ethanol/administration & dosage , Liver Neoplasms/therapy , Adult , Aged , Bile Duct Neoplasms , Carcinoma, Hepatocellular/pathology , Combined Modality Therapy , Female , Humans , Liver Neoplasms/pathology , Male , Middle Aged , Retrospective Studies , Survival Rate , Treatment Outcome
12.
Zhonghua Yi Xue Za Zhi ; 91(1): 48-50, 2011 Jan 04.
Article in Chinese | MEDLINE | ID: mdl-21418963

ABSTRACT

OBJECTIVE: To study the prognosis of fibroid after ultrasound-guidance percutaneous microwave ablation (PMAUF). METHODS: From Mar. 2007 to Jul.2010 forty uterine fibroids in forty patients with symptoms which were diagnosed in our hospital accepted PMAUF. One day after treatment blood supply within the fibroid was evaluated, by enhanced MRI. The size of fibroid was measured by ultrasonography in one year with 3 months interval, the monthly menstrual of patient was followed and the mass discharge through vagina were collected for pathological examination. RESULTS: Among the 40 fibroid nodules, 22 are intramural fibroids, 15 subserosal fibroids and 3 submucosal fibroids. The baseline mean diameter of the fibroids ranged from (3.7 to 9.0) cm, with an average of (6.4 ± 1.5) cm. The mean volume ranged from (14.6 - 341.1) cm(3), with an average of (140.1 ± 87.4) cm(3). Three months after treatment, the anechoic zone was observed within the ablated nodules and disappeared in six to seven months. the echo of ablated zone keep higher than the surrounding tissue, whereas the size of fibroid shrank significantly. Meat tissue was discharged from vagina in 8 patients (2 cases of submucosal fibroids, 6 cases intramural fibroids) in the period of menstrual in 1 - 8 months after ablation. The largest dimension of the discharge was 2.1 cm. Pathological examination confirmed the discharges as necrotic fibroid. The patients with subserosal fibroid had no discharge of necrotic tissue. The fibroid shrink rate was higher in the patients with vaginal discharges than that without vaginal discharges (P < 0.01). CONCLUSIONS: After PMAUF necrotic tissue of submucosal and intramural fibroids can be discharged through vagina, liquefaction in the center of subserosal and intramural fibroids may occur and be absorbed gradually, that may be the main reasons for fibroids reduced significantly or disappearance.


Subject(s)
Catheter Ablation/methods , Leiomyoma/therapy , Microwaves/therapeutic use , Uterine Neoplasms/therapy , Adult , Female , Follow-Up Studies , Humans , Middle Aged , Treatment Outcome , Ultrasonic Therapy
13.
Zhonghua Yi Xue Za Zhi ; 91(39): 2749-52, 2011 Oct 25.
Article in Chinese | MEDLINE | ID: mdl-22322052

ABSTRACT

OBJECTIVE: To assess the feasibility of percutaneous microwave ablation in the treatment of diffuse adenomyosis. METHODS: With a mean age of 39.2 years old, 16 patients with symptomatic adenomyosis underwent percutaneous microwave ablation (PMA). The symptoms included severe dysmenorrheal and anemia. The definite diagnosis was made by magnetic resonance (MR) imaging. Two microwave therapeutic antennas were inserted into the myometrium with adenomyosis. The microwave emission was seized when the ablated zone was over half of the total lesion. The complications, side effects and early therapeutic effects were observed during the period of treatment and at 3 and 6 months post-treatment. RESULTS: The average ablation duration was 700 s. The average ablated area was 72% (range: 60% - 80%). None of the patients developed complications during and after ablation. Fifteen patients had normal menstrual onset during the month of receiving ablation and one case at Day 30. The amount of menstrual bleeding was less than that before treatment. Dysmenorrhea disappeared after treatment in 13 cases, relieved markedly in 2 and no improvement in 1. The endometrial ectopic growth was not observed after treatment. CONCLUSION: The early clinical efficacy of PMA under ultrasound guidance is definite in the treatment of adenomyosis. The symptoms may be eliminated or effectively relieved after treatment. Easy to perform, minimal invasive and safe, the procedure of PMA is an effective therapeutic modality for adenomyosis with the preservation of uterus.


Subject(s)
Catheter Ablation/methods , Microwaves/therapeutic use , Myometrium , Uterine Diseases/surgery , Adult , Feasibility Studies , Female , Humans , Middle Aged , Ultrasonography, Interventional
14.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 10(5): 466-7, 2002 Oct.
Article in Chinese | MEDLINE | ID: mdl-12513751

ABSTRACT

The significance of detecting the recipient's Rh D blood type before transfusion and the feasibility of in-time transfusion to Rh D-negative person with the same ABO type blood or autologous blood were explored. For 2,168 inpatients who applied for transfusion for the first time in the latest five years, Rh D-antigen was detected a day before transfusion by test tube method with IgM anti-D serum provided by BASO company. The results showed that seven Rh D-negative cases were found among 2,168 cases and the Rh D-negative rate was 0.32%. Of these seven cases, two were received autologous blood, two were received Rh D-negative blood of the same type and the other three were not treated with transfusion. It is concluded that hemolytic reaction of transfusion was prevented by detecting Rh D blood type before transfusion, autologous transfusion may be taken if the patient's health-condition permits.


Subject(s)
Blood Transfusion , Rh-Hr Blood-Group System/analysis , ABO Blood-Group System , Adult , Aged , Female , Humans , Male , Middle Aged
SELECTION OF CITATIONS
SEARCH DETAIL
...