Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Inorg Chem ; 58(19): 13440-13445, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31556288

RESUMO

Thin films have attracted much interest because they often have novel properties different from those of their bulk counterparts. In this work, we tune two metastable states in three kinds of lanthanum cobalt oxide thin films by electron beam irradiation and record their dynamic transition process in situ in a transmission electron microscope. The lanthanum cobalt oxide thin films exhibit a homogeneous microstructure in the initial state and then transfer to a stripelike superstructure with 3a0 periodicity (a0 is the perovskite lattice parameter), further developing into a superstructure with 2a0 periodicity in dark stripes (brownmillerite structure). To explore the inherent energy discrepancy within the two metastable states, we perform first-principles calculations on a LaCoO3-δ (0 ≤ δ ≤ 0.5) thin film system by geometry optimization. The calculation results suggest that the forming energy of the 3a0 periodicity stripelike structure is a little lower than that of the 2a0 periodicity in the LaCoO3-δ thin film. Our work explains why the two stripelike structures coexist in lanthanum cobalt oxide thin films and extends prospective applications related to oxygen vacancies in thin films.

2.
ACS Appl Mater Interfaces ; 11(40): 36800-36806, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31539219

RESUMO

The oxygen vacancy profile in LaCoO3 exhibits rich phases with distinct structures, symmetries, and magnetic properties. Exploration of the lattice degree of freedom of LaCoO3 in the transition between these different structural phases may provide a route to enable new functionality in oxide materials with potential applications. To date, the oxygen vacancy profile transition in LaCoO3 has mainly been induced by transition-metal doping or thermal treatment. Epitaxial strain was proposed to compete with the lattice degree of freedom but has not yet been rationalized. Here, the experimental findings of strain-inhibited structural transition from perovskite to brownmillerite during the electromigration of oxygen vacancies in epitaxial LaCoO3 thin films are demonstrated. The results indicate that the oxygen vacancy ordering phase induced by the electric field is suppressed locally by both epitaxial strain field and external loads shown by in situ aberration-corrected (scanning)/ transmission electron microscopy. The demonstrated complex interplay between the electric and strain fields in the structural transitions of LaCoO3 opens up prospects for manipulating new physical properties by external excitations and/or strain engineering of a substrate.

3.
Oncol Lett ; 18(2): 2082-2090, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31423281

RESUMO

Primary pulmonary non-Hodgkin's lymphoma (PP-NHL) is a rare entity with non-specific symptoms and radiographic findings, as well as a difficult preoperative diagnosis. A limited number of studies have described PP-NHL in Chinese patients. The goal of the present study was to improve early diagnosis by examining prognostic factors in patients with PP-NHL. Therefore, a total of 29 patients with PP-NHL were included in the study between January 2001 and June 2017, including 14 with aggressive-type and 15 with indolent-type lymphomas (10 male, 19 female; median age, 50.3 years; range, 19-87 years). Pulmonary nodules and masses (55.2%) were the most common radiographic features. The diagnostic yield was 80% (12/15) by endobronchial biopsy or transbronchial lung biopsy and 100% by computed tomography (CT)-guided percutaneous needle lung biopsy (11/11) or surgery (8/8). Elevated lactate dehydrogenase levels and systemic symptoms were observed considerably more often in patients with aggressive disease than in those with indolent disease. The 1-, 3- and 5-year overall survival (OS) rates were 42, 32, and 21%, respectively, for all patients, 72, 57 and 43%, respectively, for patients with indolent lymphomas, and 13, 6 and 0%, respectively, for patients with aggressive lymphomas. The median OS rate for all patients was 12.0 months; however, the OS rate for patients with aggressive lymphomas was significantly shorter compared with those with indolent lymphomas (7.1 months vs. 16.6 months; P=0.002). Aggressive vs. indolent lymphoma status was indicated to be an independent prognostic factor for poor 5-year OS rate (hazard ratio, 5.98; P=0.014). In conclusion, bronchoscopic and CT-guided percutaneous needle lung biopsies were the most useful and least invasive procedures for diagnosing PP-NHL. Furthermore, aggressive PP-NHL was highly associated with poor 5-year OS rate and a poor prognosis.

4.
Photodiagnosis Photodyn Ther ; 26: 97-100, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30836209

RESUMO

BACKGROUND: Photodynamic therapy (PDT) is one of the treatment options for generalized facial flat warts, which results in elimination of virus and inhibition of proliferation of warts due to photochemical and phototoxic reactions. In this research, we attempted to evaluate the efficacy and safety profiles of a combination of 2940-nm laser and PDT for the treatment of generalized recalcitrant facial flat warts. METHODS: Retrospective analysis of the patients with recalcitrant facial warts was performed. Patients in the combined group (n = 40) were treated with a 2940-nm single spot abrasion followed by a PDT; while the PDT group (n = 40) received a PDT treatment only. The efficacy was assessed by the lesion numbers and lesion clearance rate. The effective rate was calculated with the cured and excellent response rates. RESULTS: The combined group showed significant improvements in the total effective rate (77.5%vs. 57.5%, p = 0.0416) and average clearance rate (81.68±2.83% vs. 68.13 ± 3.97%, p = 0.0068) as compared with the PDT-only group. The degree of lesion clearance was positively correlated with the treatment times in both groups. After three months of follow-up, no relapse occurred in patients from either group. Furthermore, an accumulation of photosensitizer in the lesional areas was observed in the combined treatment group. CONCLUSIONS: A combination of 2940-nm laser and PDT was safe and showed significantly more effect than PDT alone in treatment for recalcitrant facial flat warts, partially due to the improved uptake of photosensitizer after 2940-nm laser induced skin abrasion.


Assuntos
Ácido Aminolevulínico/administração & dosagem , Dermatoses Faciais/terapia , Terapia a Laser/métodos , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Adulto , Feminino , Humanos , Lasers de Estado Sólido , Masculino , Estudos Retrospectivos , Verrugas
5.
ACS Nano ; 13(1): 609-615, 2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30604953

RESUMO

Controlling electronic processes in low-dimension electron systems is centrally important for both fundamental and applied researches. While most of the previous works focused on SrTiO3-based two-dimensional electron gases (2DEGs), here we report on a comprehensive investigation in this regard for amorphous-LaAlO3/KTaO3 2DEGs with the Fermi energy ranging from ∼13 meV to ∼488 meV. The most important observation is the dramatic variation of the Rashba spin-orbit coupling (SOC) as Fermi energy sweeps through 313 meV: The SOC effective field first jumps and then drops, leading to a cusp of ∼2.6 T. Above 313 meV, an additional species of mobile electrons emerges, with a 50-fold enhanced Hall mobility. A relationship between spin relaxation distance and the degree of band filling has been established in a wide range. It indicates that the maximal spin precession length is ∼70.1 nm and the maximal Rashba spin splitting energy is ∼30 meV. Both values are much larger than the previously reported ones. As evidenced by density functional theory calculation, these unusual phenomena are closely related to the distinct band structure of the 2DEGs composed of 5d electrons. The present work further deepens our understanding of perovskite conducting interfaces, particularly those composed of 5d transition-metal oxides.

6.
ACS Appl Mater Interfaces ; 10(47): 40951-40957, 2018 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-30338983

RESUMO

Interface engineering is an important approach leading to multifunctional artificial materials. Although most of the previous works focused on the effects of the rotation/tilting of interfacial oxygen octahedron on perovskite multilayers, here, we report on a new kind of lattice distortion characterized by an off-center shift of the Mn ions within the MnO6 oxygen octahedra at the interfaces of La1- xSr xCoO3/La2/3Sr1/3MnO3/La1- xSr xCoO3/LaAlO3 trilayers ( x = 0-1/3), which drives the initially perpendicularly aligned magnetic axis of the La2/3Sr1/3MnO3 (LSMO) film toward the in-plane direction, though the film is in a strongly compressive state. It is further found that the magnetic anisotropy considerably depends on the content of Sr in La1- xSr xCoO3, enhancing as x decreases. The maximal anisotropy constant at 10 K is +2.5 × 106 erg/cm3 for the trilayers with x = 0, whereas it is -1.5 × 105 erg/cm3 for a bare LSMO film on LaAlO3. On the basis of the analysis of X-ray absorption spectroscopy and the results of density functional theory calculations, we found that the off-center displacement of the Mn ions has caused a strong orbital reconstruction at interfaces, resulting in the anomalous spin orientation against magnetoelastic coupling.

7.
Nat Commun ; 9(1): 1923, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29765023

RESUMO

Grouping different transition metal oxides together by interface engineering is an important route toward emergent phenomenon. While most of the previous works focused on the interface effects in perovskite/perovskite heterostructures, here we reported on a symmetry mismatch-driven spin reorientation toward perpendicular magnetic anisotropy in perovskite/brownmillerite heterostructures, which is scarcely seen in tensile perovskite/perovskite heterostructures. We show that alternately stacking perovskite La2/3Sr1/3MnO3 and brownmillerite LaCoO2.5 causes a strong interface reconstruction due to symmetry discontinuity at interface: neighboring MnO6 octahedra and CoO4 tetrahedra at the perovskite/brownmillerite interface cooperatively relax in a manner that is unavailable for perovskite/perovskite interface, leading to distinct orbital reconstructions and thus the perpendicular magnetic anisotropy. Moreover, the perpendicular magnetic anisotropy is robust, with an anisotropy constant two orders of magnitude greater than the in-plane anisotropy of the perovskite/perovskite interface. The present work demonstrates the great potential of symmetry engineering in designing artificial materials on demand.

8.
J Magn Reson Imaging ; 47(6): 1701-1710, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29165847

RESUMO

BACKGROUND: Diffusion-weighted imaging (DWI) has been studied in breast imaging and can provide more information about diffusion, perfusion and other physiological interests than standard pulse sequences. The stretched-exponential model has previously been shown to be more reliable than conventional DWI techniques, but different diagnostic sensitivities were found from study to study. PURPOSE: This work investigated the characteristics of whole-lesion histogram parameters derived from the stretched-exponential diffusion model for benign and malignant breast lesions, compared them with conventional apparent diffusion coefficient (ADC), and further determined which histogram metrics can be best used to differentiate malignant from benign lesions. STUDY TYPE: This was a prospective study. POPULATION: Seventy females were included in the study. FIELD STRENGTH/SEQUENCE: Multi-b value DWI was performed on a 1.5T scanner. ASSESSMENT: Histogram parameters of whole lesions for distributed diffusion coefficient (DDC), heterogeneity index (α), and ADC were calculated by two radiologists and compared among benign lesions, ductal carcinoma in situ (DCIS), and invasive carcinoma confirmed by pathology. STATISTICAL TESTS: Nonparametric tests were performed for comparisons among invasive carcinoma, DCIS, and benign lesions. Comparisons of receiver operating characteristic (ROC) curves were performed to show the ability to discriminate malignant from benign lesions. RESULTS: The majority of histogram parameters (mean/min/max, skewness/kurtosis, 10-90th percentile values) from DDC, α, and ADC were significantly different among invasive carcinoma, DCIS, and benign lesions. DDC10% (area under curve [AUC] = 0.931), ADC10% (AUC = 0.893), and αmean (AUC = 0.787) were found to be the best metrics in differentiating benign from malignant tumors among all histogram parameters derived from ADC and α, respectively. The combination of DDC10% and αmean , using logistic regression, yielded the highest sensitivity (90.2%) and specificity (95.5%). DATA CONCLUSION: DDC10% and αmean derived from the stretched-exponential model provides more information and better diagnostic performance in differentiating malignancy from benign lesions than ADC parameters derived from a monoexponential model. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1701-1710.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Carcinoma Intraductal não Infiltrante/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Adulto , Área Sob a Curva , Mama/diagnóstico por imagem , Carcinoma/diagnóstico por imagem , Feminino , Fibroadenoma/diagnóstico por imagem , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/métodos , Invasividade Neoplásica , Variações Dependentes do Observador , Estudos Prospectivos , Curva ROC , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estatísticas não Paramétricas
10.
Eur Radiol ; 26(11): 3888-3898, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26863896

RESUMO

OBJECTIVES: To compare diagnostic performance for breast lesions by quantitative parameters derived from intravoxel incoherent motion (IVIM) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and to explore whether correlations exist between these parameters. METHODS: IVIM and DCE MRI were performed on a 1.5-T MRI scanner in patients with suspicious breast lesions. Thirty-six breast cancers and 23 benign lesions were included in the study. Quantitative parameters from IVIM (D, f and D*) and DCE MRI (Ktrans, Kep, Ve and Vp) were calculated and compared between malignant and benign lesions. Spearman correlation test was used to evaluate correlations between them. RESULTS: D, f, D* from IVIM and Ktrans, Kep, Vp from DCE MRI were statistically different between breast cancers and benign lesions (p < 0.05, respectively) and D demonstrated the largest area under the receiver-operating characteristic curve (AUC = 0.917) and had the highest specificity (83 %). The f value was moderately statistically correlated with Vp (r = 0.692) and had a poor correlation with Ktrans (r = 0.456). CONCLUSIONS: IVIM MRI is useful in the differentiation of breast lesions. Significant correlations were found between perfusion-related parameters from IVIM and DCE MRI. IVIM may be a useful adjunctive tool to standard MRI in diagnosing breast cancer. KEY POINTS: • IVIM provided diffusion as well as perfusion information • IVIM could help differential diagnosis of breast lesions • Correlations were found between perfusion-related parameters from IVIM and DCE MRI.


Assuntos
Carcinoma de Mama in situ/patologia , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Adulto , Idoso , Meios de Contraste/farmacocinética , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Gadolínio DTPA/farmacocinética , Humanos , Pessoa de Meia-Idade , Movimento (Física) , Variações Dependentes do Observador , Perfusão , Curva ROC , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
11.
Chem Commun (Camb) ; 51(27): 5955-8, 2015 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-25735867

RESUMO

We describe for the first time a convenient technique to prepare helical CdS nanotubes, with a MOF as the template. The prepared helical CdS nanotubes were remarkably sensitive to D/L-aspartic acid (Asp) and can be used as a potential sensor for enantioselective recognition of D/L-Asp.


Assuntos
Ácido Aspártico/análise , Compostos de Cádmio/química , Nanotubos/química , Compostos de Selênio/química , Ácido Aspártico/química , Microscopia Eletrônica de Varredura , Nanotubos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo
12.
Anal Chem ; 86(2): 1277-81, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24380495

RESUMO

Homochiral metal-organic frameworks with fine-tuned pore sizes/walls and large surface areas are promising porous materials for enantioseparation considering the traditional zeolite molecular sieves have no chirality. Using enantiopure pyridyl-functionalized salen [(N-(4-Pyridylmethyl)-L-leucine·HBr)] as a starting material, we have prepared a noninterpenetrated three-dimensional homochiral metal organic framework {[ZnLBr]·H2O}n, which was further used as a chiral stationary phase for high-performance liquid chromatography to enantioseparate racemic drugs, showing excellent performances in enantioseparation of drugs. The metal-organic framework can be regarded as a novel molecular sieve-like material with a chiral separation function based on the relative sizes of the chiral channels and the resolved molecules.


Assuntos
Benzoína/isolamento & purificação , Álcoois Benzílicos/isolamento & purificação , Cromatografia Líquida de Alta Pressão/instrumentação , Complexos de Coordenação/química , Ibuprofeno/isolamento & purificação , Cetoprofeno/isolamento & purificação , Naproxeno/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Complexos de Coordenação/síntese química , Etilenodiaminas/química , Porosidade , Piridinas/química , Estereoisomerismo , Zinco/química
13.
Exp Anim ; 62(3): 205-10, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23903055

RESUMO

Qualitative measurement of the infective level is relatively difficult in experimental vaginal candidiasis. Female BALB/c mice aged 8 to 10 weeks were randomly divided into E1, E2 and E0 groups, which received subcutaneous injection of 0.05 mg, 0.1 mg of estradiol benzoate or 0.1 ml soybean oil 3 days before vaginal inoculation, respectively, and hormone treatment continued every other day thereafter. Each group was further divided into infected and noninfected subgroups. The infected mice were inoculated intravaginally with 10 µl (5 × 10(4) conidia) of Candida albicans suspension, while the noninfected mice were inoculated with 10 µl phosphate-buffered saline. Direct microscopic examination, colony count and vaginal histopathology including infection degree and inflammation extent were performed at 3, 7 and 14 days post inoculation. Estrogen treatment increased the vaginal fungal burden and extent of infection and inflammation compared with the control group, and 0.3 mg/week estrogen generally induced more severe infection and inflammation than 0.15 mg/week estrogen did. Colony count peaked on day 3 and decreased remarkably after 7 days. Infection score increased gradually during the first 7 days and decreased on day 14, while inflammation extent exacerbated progressively over the course of 14 days. This study demonstrates that the modified histological scoring system might be more feasible than colony count for evaluation of infectivity and dynamic change in experimental vaginal candidiasis.


Assuntos
Candidíase Vulvovaginal/microbiologia , Candidíase Vulvovaginal/patologia , Contagem de Colônia Microbiana/métodos , Técnicas Histológicas/métodos , Animais , Candidíase Vulvovaginal/diagnóstico , Progressão da Doença , Estradiol/administração & dosagem , Estradiol/efeitos adversos , Estradiol/análogos & derivados , Estudos de Viabilidade , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Índice de Gravidade de Doença
14.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 30(5): 544-8, 2012 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-23173325

RESUMO

OBJECTIVE: To investigate the effect of novel porous calcium phosphate cement (CPC) scaffoldings on attachment, proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs). METHODS: BMSCs of Beagle dogs were implanted and cultured with CPC scaffoldings in vitro, tricalcium phosphate (TCP) and poly (lactide-coglycolide) (PLGA) scaffoldings as controls. The attachment, proliferation and differentiation of BMSCs were detected through morphological characters, growth curve and the semi-quantitative detection of alkaline phosphatase (ALP) and osteocalcin (OC) activity. RESULTS: Cell morphology and growth curve illustrated that BMSCs attached to and grown better on the surface of novel porous CPC scaffoldings than that of PLGA group (P < 0.05). Semi-quantitative analysis of ALP showed that ALP expression level in BMSCs on the CPC and TCP group were significantly higher than that of the PLGA group (P < 0.05), the CPC group was slightly higher than the TCP group, but no significant difference was found between the two groups (P > 0.05). The staining and semi-quantitative analysis results of OC demonstrated that calcium deposition of the PLGA group was significantly less than the CPC and TCP group on both observation point (P < 0.05), but no significant difference between the CPC and TCP group (P > 0.05). CONCLUSION: The novel porous CPC material used in this study has good biocompatibility similar to TCP but much better than PLGA which is favorable of BMSCs adhesion, proliferation and osteogenic differentiation. The novel porous CPC material is a suitable scaffolding for BMSCs to fabricate tissue-engineered bone in vitro.


Assuntos
Células da Medula Óssea , Osteogênese , Animais , Osso e Ossos , Fosfatos de Cálcio , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Cemento Dentário , Cães , Osteocalcina , Engenharia Tecidual
15.
Eur J Radiol ; 81(11): 3146-53, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22677617

RESUMO

PURPOSE: To reduce radiation dose for retrospective ECG-triggered helical 256-slice CTCA by determining an optimal body size index to prospectively adjust tube current. METHODS: 102 consecutive patients with suspected CAD underwent retrospective ECG-triggered CTCA using 256-slice CT scanner. Six body size indexes including BMI, nipple level (NL) bust, thoracic anteroposterior diameter at NL, chest circumference (CC) at NL, left main and right coronary artery (RCA) origin level were measured and their correlation with noise was evaluated using linear regression. An equation was developed to use this index to adjust tube current. Additional 102 consecutive patients were scanned with the index-based mAs adjustment. A t-test for independent samples was used to compare radiation dose levels with and without the index-based mAs selection method. RESULTS: Linear regression indicated that CC RCA had the best correlation with noise (R2=0.603). Effective radiation dose was reduced from 16.6±0.9 to 9.8±2.7 mSv (p<0.01), i.e. 40.9% lower dose with the CC RCA-adapted tube current method. The image quality scores indicated no significant difference with and without the size-based mAs selection method. CONCLUSION: An accessible measure of body size, such as CC RCA, can be used to adapt tube current for individualized radiation dose control.


Assuntos
Tamanho Corporal , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Doses de Radiação , Proteção Radiológica/métodos , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada Espiral/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Técnicas de Imagem de Sincronização Cardíaca , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto Jovem
16.
Huan Jing Ke Xue ; 33(3): 720-6, 2012 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-22624360

RESUMO

The concentrations of total dissolved inorganic arsenic (TDIAs) were measured by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS). Two cruises were carried out in the river, estuary, coastal area and groundwater of eastern Hainan in December 2006 and August 2007. The concentrations of TDIAs in the Wanquan and Wenchang/Wenjiao rivers and their estuaries, coastal area in December 2006 were 4.0-9.4, 1.3-13.3, 13.3-17.3 nmol x L(-1), respectively. The concentrations of TDIAs in the Wanquan and Wenchang/Wenjiao rivers and their estuaries, coastal area in August 2007 were 1.6-15.5, 2.4-15.9, 10.8-17.6 nmol x L(-1), respectively. There was no significantly seasonal variation of TDIAs in the rivers and estuaries during the dry and wet seasons. Compared with other areas in the world, the concentration of TDIAs in the Eastern Hainan remained at pristine levels. TDIAs showed conservatively mixing in the both estuaries. The concentration of TDIAs of groundwater was below detection limit (BDL)-41.7 nmol x L(-1). The submarine groundwater discharge (SGD) to the coastal area was estimated in the drainage basin of Wenchang/Wenjiao river based on the average concentration of TDIAs in the groundwater and SGD water discharge, with the value of 1 153 mol x a(-1). Budget estimation indicated that the SGD discharge is one of the important sources of arsenic in the coastal area.


Assuntos
Arsenicais/análise , Monitoramento Ambiental , Compostos Inorgânicos/análise , Poluentes Químicos da Água/análise , China , Oceanos e Mares , Rios , Estações do Ano , Solubilidade
17.
Pediatr Radiol ; 41(7): 858-66, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21534003

RESUMO

BACKGROUND: There are a limited number of reports on the technical and clinical feasibility of prospective electrocardiogram (ECG)-gated multi-detector computed tomography (MDCT) in infants with congenital heart disease (CHD). OBJECTIVE: To evaluate image quality and radiation dose at weight-based low-dose prospectively gated 256-slice MDCT angiography in infants with CHD. MATERIALS AND METHODS: From November 2009 to February 2010, 64 consecutive infants with CHD referred for pre-operative or post-operative CT were included. All were scanned on a 256-slice MDCT system utilizing a low-dose protocol (80 kVp and 60-120 mAs depending on weight: 60 mAs for ≤ 3 kg, 80 mAs for 3.1-6 kg, 100 mAs for 6.1-10 kg, 120 mAs for 10.1-15 kg). RESULTS: No serious adverse events were recorded. A total of 174 cardiac deformities, confirmed by surgery or heart catheterization, were studied. The sensitivity of MDCT for cardiac deformities was 97.1%; specificity, 99.4%; accuracy, 95.9%. The mean heart rate during scan was 136.7 ± 14.9/min (range, 91-160) with a corresponding heart rate variability of 2.8 ± 2.2/min (range, 0-8). Mean scan length was 115.3 ± 11.7 mm (range, 93.6-143.3). Mean volume CT dose index, mean dose-length product and effective dose were 2.1 ± 0.4 mGy (range, 1.5-2.8), 24.7 ± 5.9 mGy·cm (range, 14.7-35.8) and 1.6 ± 0.3 mSv (range, 1.1-2.5), respectively. Diagnostic-quality images were achieved in all cases. Satisfactory diagnostic quality for visualization of all/proximal/distal coronary artery segments was achieved in 88.4/98.8/80.0% of the scans. CONCLUSION: Low-dose prospectively gated axial 256-slice CT angiography is a valuable tool in the routine clinical evaluation of infants with CHD, providing a comprehensive three-dimensional evaluation of the cardiac anatomy, including the coronary arteries.


Assuntos
Técnicas de Imagem de Sincronização Cardíaca/métodos , Angiografia Coronária/métodos , Cardiopatias Congênitas/diagnóstico por imagem , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Meios de Contraste , Feminino , Cardiopatias Congênitas/fisiopatologia , Frequência Cardíaca , Humanos , Lactente , Recém-Nascido , Iohexol/análogos & derivados , Masculino , Estudos Prospectivos , Sensibilidade e Especificidade
18.
Zhongguo Fei Ai Za Zhi ; 11(5): 649-51, 2008 Oct 20.
Artigo em Chinês | MEDLINE | ID: mdl-20738905
19.
Acta Crystallogr Sect E Struct Rep Online ; 64(Pt 1): m105, 2007 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-21200464

RESUMO

In the title compound, [Cu(C(8)H(4)F(3)O(2)S)Cl(C(12)H(8)N(2))], the Cu(II) ion exhibits a distorted square-pyramidal geometry. The coordination environment of the cation comprises two N atoms from 1,10-phenanthroline and two O atoms from thenoyltrifluoro-acetone in the basal plane and one Cl(-) anion at the apical site. There are weak inter-molecular C-H⋯Cl bonds.

20.
Acta Crystallogr Sect E Struct Rep Online ; 64(Pt 1): m182, 2007 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-21200530

RESUMO

In the title compound, [Zn(C(9)H(11)N(3))(2)](ClO(4))(2), the Zn(II) atom resides on a crystallographic twofold axis and is coordinated by two benzimidazole N [Zn⋯N = 1.993 (4) Å] and two amine N atoms [Zn⋯N = 2.036 (4) Å] in a distorted tetra-hedral geometry. The crystal packing is dominated by N-H⋯O inter-actions involving the perchlorate anions and π-π stacking inter-actions with an inter-planar separation of 3.42 Å. A weak C-H⋯O inter-action is also present.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA