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1.
Inorg Chem ; 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39231304

RESUMO

The photophysical properties and luminescent mechanism of a series of tripod-type Cu(I) complexes in solution and solids were comprehensively investigated through theoretical simulations. From a microscopic perspective, the experimental phenomenon is explained: (1) The intrinsic reason for the quenching of complex 1 in solution was attributed to the significant nonradiative transition caused by structural deformation; (2) In the solid, the reduced ΔEST for complex 2 effectively facilitate reverse intersystem crossing (RISC) and improves its luminescence efficiency; (3) The enhanced performance of complex 3 in solution is attributed to that its stronger steric hindrance is advantageous to decrease not only the ΔEST but also the reorganization energy through intramolecular weak interactions. Based on complex 3, the tert-butyl substituted isomeric complex 4 was designed. Complex 4 further amplifies the advantages of 3 to further promote the RISC to make full use of excitons. Meanwhile, it has an emission wavelength of 462.6 nm, which makes it an excellent candidate for high-efficiency deep-blue TADF materials. This study provides valuable information for obtaining efficient blue phosphorescence and TADF dual-channel luminescent materials.

2.
Nat Prod Res ; : 1-10, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39084318

RESUMO

The Paeonia ostii, also known as "Feng Dan" have a crucial role in folk medicine to treat lumbar muscles strain, knee osteoarthritis and cervical spondylosis. In this study, four new phenolic compounds, specifically Paeoniaostiph A-E (1-4) phenolic compounds were characterised through spectroscopic techniques, including 1D and 2D NMR, HRESIMS, UV, IR, and electronic circular dichroism computations to explore their structures. Cytotoxicity and NO production inhibition of the new phenolic compounds were also studied. The results of the cytotoxicity experiment showed that compound 1 is cytotoxic to two human cancer cell lines with IC50 values ranging from 13.3 to 13.5 µM. Compounds 1 and 2 showed certain inhibitory activity on NO production. This is the first report on isolating the components from natural sources.

3.
Fitoterapia ; 175: 105941, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38575089

RESUMO

Four undescribed compounds including three harzianic acids (1, 3 and 4) and one oxazolidinone (2), along with three known ones (5-7) were isolated from the solid fermented product of endophytic fungus Ilyonectria sp., their structures were elucidated as 1-amino-harzianic acid (1), ilyonectria-oxazolidinone (2),10'-nor- isoharzianic acid (3), isohomoharzianic acid (4), harzianic acid (5), isoharzianic acid (6), homoharzianic acid (7) by means of detailed chemical evidences and spectroscopic data analysis. All the compounds were evaluated for cytotoxicity against SMMC-7721 human cancer cell lines by MTS assay. Among the seven tested compounds, 1-amino-harzianic acid (1) demonstrated well cytotoxic activity against SMMC-7721 with IC50 value of 26.84 µM. The results of molecular docking indicated that compound exhibited moderate anti-tumor activity may through binding to apoptosis related proteins.


Assuntos
Antineoplásicos , Simulação de Acoplamento Molecular , Oxazolidinonas , Humanos , Linhagem Celular Tumoral , Estrutura Molecular , Antineoplásicos/farmacologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/química , Oxazolidinonas/farmacologia , Oxazolidinonas/isolamento & purificação , Endófitos/química , China , Hypocreales/química
4.
Phytochemistry ; 221: 114046, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38460780

RESUMO

Eight previously undescribed chromones eleusineketones A-H (1-8), as well as eight known compounds (9-16), were isolated from the endophytic fungus Bipolaris eleusines. These planar structures were created using an in-depth analysis of their spectral data, which included 1D, 2D, and HRESIMS data. Furthermore, the absolute configurations of compounds 1, 2, and 6 were determined by spectroscopic analysis and quantum chemical computational approaches, and compound 5 was determined by single-crystal X-ray diffraction analysis. The cytotoxic activity assay revealed that compounds 1 and 5 both inhibited MDA-MB-231 cells with IC50 values of 14.48 µM and 17.99 µM, respectively.


Assuntos
Ascomicetos , Cromonas , Estrutura Molecular , Cromonas/farmacologia , Cromonas/química , Bipolaris , Ascomicetos/química
5.
Nat Prod Bioprospect ; 13(1): 43, 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37870633

RESUMO

A series of terpenoids (1-17), comprising six new compounds designated bipolariterpenes A-F (1-6) and eleven recognized compounds (7-17), were isolated from the wheat culture of the potato endophytic fungus Bipolaris eleusines. Their structures and stereochemistry were clarified by HRESIMS, NMR, DP4 + probability analyses, and computations for electronic circular dichroism (ECD). All compounds are made up of six meroterpenoids, four sesterterpenes and seven sesquiterpenes. Among them, four sesterterpenes (4, 5, 10, 11) were investigated for their antifungal, antibacterial and cytotoxic properties, and six meroterpenoids (1-3, 7-9) were evaluated for their antifungal properties. The compounds 7, 9, and 10 had substantial antifungal activity against Epidermophyton floccosum at a concentration of 100 µM. No antibacterial and cytotoxic activities were observed.

6.
Molecules ; 28(6)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36985677

RESUMO

The ethnobotanical plant Marsdenia tenacissima has been used for hundreds of years for Dai people in Yunnan Province, China. Previously, chemical investigations on this plant have revealed that pregnane glycosides were the main biological constituents. Nine new pregnane glycosides, marsdeosides A-I (1-9), were isolated from cultivated dried stems of the medicinal plant Marsdenia tenacissima in this study. The structures were analyzed by extensive spectroscopic analysis, including 1D, 2D NMR, HRESIMS, and IR spectroscopic analysis. The absolute configurations of the sugar moieties were identified by comparing the Rf values and specific optical rotations with those of the commercially available standard samples and the data reported in the literature. Marsdeosides A (1) featured an unusual 8,14-seco-pregnane skeleton. Compounds 1, 8, and 9 showed activity against nitric oxide production in lipopolysaccharide-activated macrophage RAW264.7, with IC50 values of 37.5, 38.8, and 42.8 µM (L-NMMA was used as a positive control, IC50 39.3 µM), respectively. This study puts the knowledge of the chemical profile of the botanical plant M. tenacissima one step forward and, thereby, promotes the sustainable utilization of the resources of traditional folk medicinal plants.


Assuntos
Marsdenia , Plantas Medicinais , Humanos , Plantas Medicinais/química , Marsdenia/química , China , Pregnanos/química , Glicosídeos/química
7.
J Magn Reson Imaging ; 57(2): 578-586, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35852438

RESUMO

BACKGROUND: MRI-targeted biopsy (MRTB) improves the clinically significant prostate cancer (csPCa) detection rate with fewer biopsy cores in men with suspected PCa. However, whether concurrent systematic biopsy (SB) can be avoided in patients undergoing MRTB remains unclear. PURPOSE: To evaluate the potential value of MRI-based radiomics models in avoiding unnecessary SB in biopsy-naïve patients. STUDY TYPE: Retrospective. POPULATION: A total of 226 patients (mean age 66.6 ± 9.02 years) with suspicion of PCa (PI-RADS score ≥ 3) and received combined cognitive MRTB with SB were retrospectively recruited and randomly divided into training (N = 180) and test (N = 46) cohorts at an 8:2 ratio. FIELD STRENGTH/SEQUENCE: A 3.0 T, biparametric MRI (bpMRI) including T2-weighted imaging (T2WI) and apparent diffusion coefficient (ADC) map. ASSESSMENT: The whole prostate gland (PG) and the index lesion (IL) were delineated. Three radiomics models of bpMRIPG , bpMRIIL , and bpMRIPG+IL were constructed, respectively, and the performance of each radiomics model was compared with that of PI-RADS assessment. STATISTICAL TESTS: The least absolute shrinkage and selection operator (LASSO) regression method was used to select texture features. The area under the curve (AUC) and decision curve analysis were used to estimate the models. RESULTS: The bpMRIPG+IL radiomics model exhibited good discrimination, calibration, and net benefits, which would reduce the SB biopsy in 71.2% and 71.4% of men with PI-RADS ≥ 5 lesions in the training and test cohorts, respectively. DATA CONCLUSION: A bpMRIPG+IL radiomics model may outperform PI-RADS category in help reducing unnecessary SB in biopsy-naïve patients. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 6.


Assuntos
Neoplasias da Próstata , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Biópsia , Biópsia Guiada por Imagem/métodos , Imageamento por Ressonância Magnética/métodos , Próstata/diagnóstico por imagem , Próstata/patologia , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Estudos Retrospectivos
8.
Orthop Surg ; 13(7): 2163-2169, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34516043

RESUMO

OBJECTIVE: To investigate the curative effect of closed reduction and external fixation in the treatment of grade IV supination-external rotation fractures of the ankle joint. METHODS: Fifty-six patients treated with closed reduction and external fixation from February 2016 to March 2020 were included in this retrospective study, all with sprains. After receiving nerve block anesthesia, the patient underwent closed reduction under C-arm fluoroscopy, and the ankle joint was fixed in a dorsiflexion-inversion position with casting and splints after the end of the fracture met the reduction standard by fluoroscopy. One week and four weeks after the reduction treatment, oblique axial and coronal MR scans of the ankle joint were performed to determine the degree of injury and healing of the inferior tibiofibular syndesmosis; anteroposterior and lateral X-rays of the ankle joint (including the ankle acupoints) were regularly reviewed to observe the fracture alignment and healing. Combined with the images and physical examination, the patients were instructed to undergo ankle weight-bearing rehabilitation training when they met the clinical healing standard, and at the last follow-up, the Mazur ankle evaluation and grading system were used for evaluation. After the reduction, the images were evaluated according to the Leeds standard. The image healing of fracture was evaluated by callus growth criteria. RESULTS: The follow-up period of patients ranged from 11 to 58 months, with an average of 26.8 months. The clinical healing time was (8.51 ± 2.12) weeks. The excellent and good rating after reduction was 82.1%, and the excellent and good rating during clinical fracture healing was 73.2%, according to the Leeds imaging evaluation. According to the Mazur ankle evaluation and grading system, the excellent and good rating was 75.0%. Pairwise comparison of callus images at 4, 6 and 12 weeks showed statistically significant differences (P < 0.05), suggesting callus growth at different time periods. A total of 56 patients had anterior inferior tibial fibular ligament (AITFL) injuries (grade II-III), among which 11 patients had AITFL injuries combined with grade II injuries of the interosseous ligament (IOL) and 4 patients had AITFL injuries combined with grade III injuries of the IOL. CONCLUSIONS: Most of the patients with grade IV supination-external rotation fracture of the ankle joint had good prognosis after closed reduction and plaster combined with splint fixation. For patients with IOL injury who had poor prognosis, open reduction and internal fixation therapy is appropriate.


Assuntos
Fraturas do Tornozelo/cirurgia , Moldes Cirúrgicos , Redução Fechada/métodos , Adulto , Idoso , Fraturas do Tornozelo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Radiografia , Estudos Retrospectivos
9.
EClinicalMedicine ; 32: 100751, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33681744

RESUMO

BACKGROUND: The safety and effectiveness of intramuscular olanzapine or haloperidol compared to midazolam as the initial pharmacological treatment for acute agitation in emergency departments (EDs) has not been evaluated. METHODS: A pragmatic, randomised, double-blind, active-controlled trial was conducted from December 2014 to September 2019, in six Hong Kong EDs. Patients (aged 18-75 years) with undifferentiated acute agitation requiring parenteral sedation were randomised to 5 mg intramuscular midazolam (n = 56), olanzapine (n = 54), or haloperidol (n = 57). Primary outcomes were time to adequate sedation and proportion of patients who achieved adequate sedation at each follow-up interval. Sedation levels were measured on a 6-level validated scale (ClinicalTrials.gov Identifier: NCT02380118). FINDINGS: Of 206 patients randomised, 167 (mean age, 42 years; 98 [58·7%] male) were analysed. Median time to sedation for IM midazolam, olanzapine, and haloperidol was 8·5 (IQR 8·0), 11·5 (IQR 30·0), and 23·0 (IQR 21·0) min, respectively. At 60 min, similar proportions of patients were adequately sedated (98%, 87%, and 97%). There were statistically significant differences for time to sedation with midazolam compared to olanzapine (p = 0·03) and haloperidol (p = 0·002). Adverse event rates were similar across the three arms. Dystonia (n = 1) and cardiac arrest (n = 1) were reported in the haloperidol group. INTERPRETATION: Midazolam resulted in faster sedation in patients with undifferentiated agitation in the emergency setting compared to olanzapine and haloperidol. Midazolam and olanzapine are preferred over haloperidol's slower time to sedation and potential for cardiovascular and extrapyramidal side effects. FUNDING: Research Grants Council, Hong Kong.

10.
Inorg Chem ; 59(17): 12039-12053, 2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32786269

RESUMO

Investigation of the clear structure-property relationship and microscopic mechanism of thermally activated delayed fluorescence (TADF) emitters with high emission quantum yield is a direction worthy of continuous efforts. The instructive theoretical principle of TADF material design is critical and challenging. Here, we carried out theoretical calculation on two experimental Cu(I) complexes with the same 7,8-bis(diphenylphosphino)-7,8-dicarba-nido-undecaborate (dppnc) but different N^N ligands [dmbpy = 6,6'-dimethyl-2,2'-bipyridine (1) or dmp = 2,9-dimethyl-1,10-phenanthroline (2)] to briefly elaborate the structure-TADF performance relationship and luminescence mechanism. It was found that enhanced rigidity by the fused benzene ring between two pyridyl units in complex 2 leads to (i) higher allowedness of S1 → S0, (ii) more effective reverse intersystem crossing (RISC), and (iii) better relative stability of the T1 state, which could be responsible for its excellent TADF behavior. Thus, a strategy of extending π conjugation in the N^N ligand could be deduced to further enhance the quantum yield. We validated it and have succeeded in designing analogue complex 4 by extending π conjugation with an electron-withdrawing pyrazinyl. Benefiting from the smaller energy gap (ΔEST) and plunged reorganization energy between the S1 and T1 states, the rate of RISC in complex 4 (1.05 × 108 s-1) increased 2 orders of magnitude relative to that of 2 (5.80 × 106 s-1), showing more superiority of the TADF behavior through a better balance of RISC, fluorescence, and phosphorescence decay. Meanwhile, the thermally activated temperature of 4 is only 165 K, implying that there is a low-energy barrier. All of these indicate that the designed complex 4 may be a potential TADF candidate.

11.
Undersea Hyperb Med ; 45(4): 403-409, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30241119

RESUMO

Hyperbaric oxygen (HBO2) is widely used in clinical settings for many disease treatments. To investigate the potential effects of hyperbaric oxygen on patients with slow coronary flow (SCF) we retrospectively analyzed 98 patients who were diagnosed with SCF by coronary artery angiography. Of these, 50 patients received conventional treatment only (control group; the other 48 patients received hyperbaric oxygen treatment for four weeks in addition to the routine therapy (HBO2 group). By using gated myocardial perfusion tomography examination before and after treatment, we observed that 71 out of 148 (47.9%) subsegments of injured myocardium improved in the control group, while 108 out of 151 (71.5%) subsegments of injured myocardium improved in the HBO2 group (P ⟨ 0.05). Furthermore, the peak filling rate (PFR), time of peak filling rate (TPFR) and mean filling rate during the first one-third of the filling time (MFR/3) were all significantly improved in HBO2-treated patients compared to those who received conventional treatment only. However, we did not detect any significant effects of only treatment on left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), nor on left ventricular ejection fraction (LVEF). Our results indicate that hyperbaric oxygen therapy can be a beneficial and effective medication to improve myocardial perfusion and left ventricular diastolic function in SCF patients.


Assuntos
Doença da Artéria Coronariana/terapia , Circulação Coronária/fisiologia , Oxigenoterapia Hiperbárica , Imagem de Perfusão do Miocárdio/métodos , Disfunção Ventricular Esquerda/terapia , Adulto , Idoso , Velocidade do Fluxo Sanguíneo , Volume Sanguíneo , Tomografia Computadorizada por Emissão de Fóton Único de Sincronização Cardíaca , Estudos de Casos e Controles , Doença da Artéria Coronariana/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Volume Sistólico/fisiologia
12.
Ying Yong Sheng Tai Xue Bao ; 25(5): 1327-34, 2014 May.
Artigo em Chinês | MEDLINE | ID: mdl-25129932

RESUMO

It is very important for studying surface energy and water balance to improve the accuracy of evapotranspiration (ET) estimation. Based on eddy covariance measurements and microclimate observational data available, comparisons were done in accuracy of simulating ET with the FAO Penman-Monteith model from the marshland, rice paddy and soybean field in the Sanjiang Plain. The results showed that the values of ET simulated with the model over marshland was significantly higher than the measured one (averagely 81.8% higher) when the crop coefficients recommend by FAO were adopted, and its modeling efficiency was negative, which indicated that the ET from the marshland couldn' t be simulated by the model. While the seasonal variation of ET over rice paddy and soybean field could be simulated by the model and the accuracy in simulating ET from rice paddy was better than that from soybean field. Crop coefficients (Kc) of marshland, rice paddy and soybean field were all significantly positively related to leaf area index, and crop coefficient of soybean field was also significantly negatively related to vapor pressure deficit. With Kc modified through linear regression, the FAO Penman-Monteith model markedly improved the estimation accuracy for marshland, rice paddy and soybean field, with the mean bias error ranging from -0.1 to 0.3 mm x d(-1), root mean square error ranging from 0.50 to 0.67 mm x d(-1) and modeling efficiency ranging from 0.69 to 0.85. Still, the accuracy in simulating ET from rice paddy was superior to that from the other two underlying surfaces. The FAO Penman-Monteith model was suitable to simulate the ET from rice paddy whether the crop coefficient was modified or not. However, the crop coefficient must be modified if the model was used to simulate the ET from marshland and soybean field.


Assuntos
Agricultura , Modelos Teóricos , Transpiração Vegetal , China , Clima , Produtos Agrícolas , Oryza , Folhas de Planta , Estações do Ano , Glycine max
13.
J Appl Clin Med Phys ; 14(5): 68-78, 2013 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-24036860

RESUMO

This study evaluated the extent of improvement in dose predication accuracy achieved by the Fast Monte Carlo algorithm (MC) compared to the Ray Tracing algorithm (RAT) in stereotactic body radiotherapy (SBRT) of non-small cell lung cancer (NSCLC), and how their differences were influenced by the tumor site and size. Thirty-three NSCLC patients treated with SBRT by CyberKnife in 2011 were recruited. They were divided into the central target group (n = 17) and peripheral target group (n = 16) according to the RTOG 0236 guidelines. Each group was further divided into the large and small target subgroups. After the computation of treatment plans using RAT, a MC plan was generated using the same patient data and treatment parameters. Apart from the target reference point dose measurements, various dose parameters for the planning target volume (PTV) and organs at risk (OARs) were assessed. In addition, the "Fractional Deviation" (FDev) was also calculated for comparison, which was defined as the ratio of the RAT and MC values. For peripheral lung cases, RAT produced significantly higher dose values in all the reference points than MC. The FDev of all reference point doses and dose parameters was greater in the small target than the large target subgroup. For central lung cases, there was no significant reference point and OAR dose differences between RAT and MC. When comparing between the small target and large target subgroups, the FDev values of all the dose parameters and reference point doses did not show significant difference. Despite the shorter computation time, RAT was inferior to MC, in which the target dose was usually overestimated. RAT would not be recommended for SBRT of peripheral lung tumors regardless of the target size. However, it could be considered for large central lung tumors because its performance was comparable to MC.


Assuntos
Algoritmos , Carcinoma Pulmonar de Células não Pequenas/cirurgia , Neoplasias Pulmonares/cirurgia , Método de Monte Carlo , Radiocirurgia , Planejamento da Radioterapia Assistida por Computador , Humanos , Órgãos em Risco , Dosagem Radioterapêutica , Estudos Retrospectivos , Carga Tumoral
14.
Brain Inj ; 26(9): 1136-42, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22630115

RESUMO

BACKGROUND: Since progressive intracranial haemorrhage (PIH) was introduced in neurosurgical literatures, several studies have been performed. PIH has been shown to be associated with a high increase in the risk of clinical worsening and related to morbidity and mortality as well. So, early detection and prediction of PIH is practically important in a clinical situation. OBJECTIVES: To investigate the risk factors related to PIH in patients with acute traumatic brain injury (TBI) and analyse their clinical significances. METHODS: PIH was confirmed by comparing the first and repeated CT scans. Data compared included gender, age, mechanism of injury, Glasgow Coma Score (GCS) at admission, timing from injury to the first CT, the signs of the initial CT scan, prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fg), thrombin time (TT), platelet (PLT) and D-dimer (D-D) values. Logistic regression analysis was used to show the risk factors related to PIH. RESULTS: A cohort of 498 patients with TBI was evaluated, and there were 139 (27.91%) patients who suffered from PIH. The differences between PIHs and non-PIHs were significant in age, GCS at admission, the signs of the initial CT scan (fracture, subarachnoid haemorrhage, brain contusion and primary haematoma), PT, Fg and D-D values (p < 0.001). Logistic regression analysis was used to identify that CT scans (subarachnoid haemorrhage, brain contusion and primary haematoma) and plasma D-D values as the most important predictors of PIH (p < 0.001). CONCLUSIONS: For patients with the initial CT scan showing subarachnoid haemorrhage, brain contusion and primary haematoma with abnormal D-D levels, an earlier and dynamic CT scan should be performed, for the detection of PIH as early as possible and the medical intervention would be enforced in time.


Assuntos
Antifibrinolíticos/farmacologia , Lesões Encefálicas/fisiopatologia , Produtos de Degradação da Fibrina e do Fibrinogênio/farmacologia , Fibrinogênio/farmacologia , Hemorragias Intracranianas/fisiopatologia , Adulto , Idoso , Lesões Encefálicas/sangue , Lesões Encefálicas/diagnóstico , Estudos de Coortes , Progressão da Doença , Feminino , Escala de Coma de Glasgow , Humanos , Hemorragias Intracranianas/sangue , Hemorragias Intracranianas/diagnóstico , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Tempo de Tromboplastina Parcial/métodos , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Tempo de Trombina/métodos , Tomografia Computadorizada por Raios X
15.
Emerg Radiol ; 18(1): 47-51, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20848151

RESUMO

Acute posterior shoulder dislocation is rare, and its early diagnosis remains a challenge to the emergency physician. This report describes two cases of acute posterior shoulder dislocation confirmed by bedside ultrasound scan performed by the emergency physician. Bedside ultrasound for diagnosis of posterior shoulder dislocation is accurate, noninvasive, repeatable, convenient, and without ionizing radiation. Dynamic ultrasound sign of posterior shoulder dislocation and using bedside ultrasound for verification of successful reduction of posterior shoulder dislocation are described.


Assuntos
Luxação do Ombro/diagnóstico por imagem , Serviços Médicos de Emergência , Humanos , Masculino , Pessoa de Meia-Idade , Sistemas Automatizados de Assistência Junto ao Leito , Ultrassonografia
16.
ACS Appl Mater Interfaces ; 2(2): 544-50, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20356203

RESUMO

Montmorillonite (MMT)-supported Ag/TiO(2) composite (Ag/TiO(2)/MMT) has been prepared through a one-step, low-temperature solvothermal technique. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) reveal that the Ag particles coated with TiO(2) nanoparticles are well-dispersed on the surface of MMT in the composite. As a support for the Ag/TiO(2) composite, the MMT prevents the loss of the catalyst during recycling test. This Ag/TiO(2)/MMT composite exhibits high photocatalytic activity and good recycling performance in the degradation of E. coli under visible light. The high visible-light photocatalytic activity of the Ag/TiO(2)/MMT composite is ascribed to the increase in surface active centers and the localized surface plasmon effect of the Ag nanoparticles. The Ag/TiO(2)/MMT materials with excellent stability, recyclability, and bactericidal activities are promising photocatalysts for application in decontamination.


Assuntos
Bentonita/química , Escherichia coli/fisiologia , Nanopartículas/administração & dosagem , Nanopartículas/química , Prata/administração & dosagem , Prata/química , Titânio/química , Sobrevivência Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Luz , Teste de Materiais , Nanopartículas/efeitos da radiação , Nanotecnologia/métodos , Prata/efeitos da radiação , Titânio/efeitos da radiação
18.
Chemistry ; 15(17): 4366-72, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19274691

RESUMO

Monodisperse gold-doped titania microspheres have been synthesized under high concentration of a titanium precursor (9.34 mM) by introducing a trace amount of chloroauric acid (CA) into the reaction system; the size of the microspheres can be easily tuned (from approximately 587 to approximately 392 nm) by varying the amount of the CA added. The plausible formation mechanism has been discussed in detail. Chloroauric acid was found to act as the stabilizing agent to induce the formation of monodisperse colloidal spheres. Gold-doped anatase titania spheres with approximately 7 nm gold nanodots on the surface were synthesized by calcination. Interestingly, results from surface photocurrent, surface photovoltage, and transient photovoltage measurements indicate that the gold nanodots exhibit different electronic properties when the gold-doped anatase titania spheres were illuminated by different wavelengths of light: one is an electron acceptor in the UV region, while the other is an electron donor in the visible region. Furthermore, the decay time of the injected plasmon-induced electrons was found to be on the millisecond timescale and increased with increasing amounts of gold doped.

19.
Inorg Chem ; 46(12): 4766-8, 2007 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-17508741

RESUMO

Novel porphyrin dimer ligand and cobalt complexes by directly bridging with l-glutamic acid have been prepared and characterized. The intensities of circular dichroism and UV-vis spectra that change the aggregate morphologies of the porphyrin dimer under different temperatures have been investigated.


Assuntos
Cobalto , Porfirinas/química , Temperatura , Dicroísmo Circular , Dimerização , Ácido Glutâmico/química , Espectrofotometria Ultravioleta
20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 26(6): 1134-7, 2006 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-16961250

RESUMO

Using sol-gel method to make tetra-meso (hydroxylphenyl) zinc porphyrin (ZnTHPP) trapped in inorganic networks of TiO2, a new organic/inorganic hybrid material was prepared. The structures and morphology of this material were characterized by thermogravimetric analyses (TGA), infrared spectrum (FTIR), UV-Vis spectrum (UV), diffuse reflectance spectroscopy (DRS), and scanning electron microscopy (SEM), indicating that ZnTHPP/TiO2 hybrid material possessed excellent thermostability, and ZnTHPP was trapped in TiO2 network with chemical bonds. In addition, ZnTHPP embedding can enlarge the absorption range of light for TiO2 effectivelly.

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