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1.
Am J Infect Control ; 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39025304

RESUMEN

BACKGROUND: Identifying patients at risk of ventilator-associated pneumonia through prediction models can facilitate medical decision-making. Our objective was to evaluate the current models for ventilator-associated pneumonia in patients with mechanical ventilation. METHODS: Nine databases systematically retrieved from establishment to March 6, 2024. Two independent reviewers performed study selection, data extraction, and quality assessment, respectively. The Prediction Model Risk of Bias Assessment Tool was used to evaluate the risk of model bias and applicability. Stata 17.0 was used to conduct a meta-analysis of discrimination of model validation. RESULTS: The total of 34 studies were included, with reported 52 prediction models. The most frequent predictors in the models were mechanical ventilation duration, length of intensive care unit stay, and age. Each study was essentially considered having a high risk of bias. A meta-analysis of 17 studies containing 33 models with validation was performed with a pooled area under the receiver-operating curve of 0.80 (95% confidence interval: 0.78-0.83). CONCLUSIONS: Despite the relatively excellent performance of the models, there is a high risk of bias of the model development process. Enhancing the methodological quality, especially the external validation, practical application, and optimization of the models need urgent attention.

2.
J Asthma ; 61(11): 1422-1431, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38767583

RESUMEN

OBJECTIVE: To investigate the role of 14-3-3ß in acute asthma exacerbations in children and analyze the risk factors for asthma exacerbations. METHODS: This study recruited 101 children with acute asthma exacerbations, 101 children with stable asthma, and 65 healthy children. Serum 14-3-3ß was compared among the three groups. Factors such as asthma family history, skin prick test, serum-specific IgE test, coinfections, and clinical indicators (FeNO, FEV1, white blood cells, eosinophils, and serum IgE level) were compared between the asthma groups. Risk factors associated with acute asthma exacerbations were identified using multivariate logistic regression models. ROC curve was drawn to determine the diagnostic sensitivity and specificity of 14-3-3ß. RESULTS: Serum 14-3-3ß was significantly greater in the acute asthma group than in the stable asthma and control groups. Serum 14-3-3ß was higher in severe acute asthma group than in mild-moderate asthma group. There were no significant differences in serum 14-3-3ß levels between stable asthma and control groups (p > .05). Multivariate logistic regression analysis revealed that serum 14-3-3ß level, FeNO, coinfection, and FEV1 z-score significantly increased the odds of acute asthma exacerbations in children. The optimal 14-3-3ß cutoff value (39.79 ng/mL), had a sensitivity of 69.3% and specificity of 94.1% for predicting acute asthma exacerbations. CONCLUSIONS: 14-3-3ß is elevated in children with acute exacerbations of asthma, and increases with exacerbation severity. 14-3-3ß, FeNO, FEV1, and coinfection could be independent risk factors for predicting asthma exacerbations. The optimal 14-3-3ß cutoff value for predicting asthma exacerbations was 39.79 ng/mL.


Asunto(s)
Proteínas 14-3-3 , Asma , Humanos , Asma/sangre , Asma/diagnóstico , Proteínas 14-3-3/sangre , Masculino , Niño , Femenino , Factores de Riesgo , Preescolar , Enfermedad Aguda , Curva ROC , Inmunoglobulina E/sangre , Modelos Logísticos , Índice de Severidad de la Enfermedad , Sensibilidad y Especificidad , Biomarcadores/sangre , Adolescente , Estudios de Casos y Controles
3.
Plant Physiol Biochem ; 207: 108426, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38340689

RESUMEN

In nature, light intensity usually fluctuates and a sudden shade-sun transition can induce photodamage to photosystem I (PSI) in many angiosperms. Photosynthetic regulation in fluctuating light (FL) has been studied extensively in C3 plants; however, little is known about how C4 plants cope FL to prevent PSI photoinhibition. We here compared photosynthetic responses to FL between maize (Zea mays, C4) and tomato (Solanum lycopersicum, C3) grown under full sunlight. Maize leaves had significantly higher cyclic electron flow (CEF) activity and lower photorespiration activity than tomato. Upon a sudden shade-sun transition, maize showed a significant stronger transient PSI over-reduction than tomato, resulting in a significant greater PSI photoinhibition in maize after FL treatment. During the first seconds upon shade-sun transition, CEF was stimulated in maize at a much higher extent than tomato, favoring the rapid formation of trans-thylakoid proton gradient (ΔpH), which was helped by a transient down-regulation of chloroplast ATP synthase activity. Therefore, modulation of ΔpH by regulation of CEF and chloroplast ATP synthase adjusted PSI redox state at donor side, which partially compensated for the deficiency of photorespiration. We propose that C4 plants use different photosynthetic strategies for coping with FL as compared with C3 plants.


Asunto(s)
Complejo de Proteína del Fotosistema I , Zea mays , Complejo de Proteína del Fotosistema I/metabolismo , Zea mays/metabolismo , ATPasas de Translocación de Protón de Cloroplastos , Fotosíntesis/fisiología , Luz , Transporte de Electrón , Complejo de Proteína del Fotosistema II/metabolismo , Hojas de la Planta/metabolismo
4.
J Pediatr (Rio J) ; 100(1): 81-87, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37741632

RESUMEN

OBJECTIVE: To investigate the diagnostic efficacy of serum IL-33 single indicator and combined indicators for asthma in children. METHODS: 132 children were initially diagnosed with asthma during acute exacerbation and 100 healthy children were included. Serum IL-33 concentration differences were compared between asthmatic and normal children. Correlations between IL-33 with pulmonary function parameters, FeNO, peripheral blood EOS counts and serum total IgE were analyzed in asthmatic children. ROC curves were used to assess IL-33 diagnostic efficacy and its combined indicators. To prevent overfitting of the predictive model, the hold-out cross-validation method was used. RESULTS: (1) Serum IL-33 concentrations were significantly higher in children with asthma than in normal children (p < 0.001). (2) IL-33 concentration was negatively correlated with FVC z-score, FEV1 z-score and FEF75% z-score in asthmatic children (p < 0.05). (3) The area under the ROC curve of IL-33 was 0.821, which was higher than those of FeNO, FVC z-score, and FEV1 z-score. (4) Cross-validation of the combined indicators showed that IL-33 significantly improved asthma diagnostic efficacy. The combination of IL-33, FEF75% z-score, and FeNO showed the highest diagnostic efficacy, with the AUC, sensitivity, and specificity of the combined indicator being 0.954, 90.1%, and 89. 0%, respectively, and good extrapolation of the predictive model. CONCLUSION: Serum IL-33 is higher in children with asthma and increases with the severity of pulmonary ventilation obstruction. A single indicator of serum IL-33 demonstrates moderate diagnostic accuracy, and its combination with FEF75% z-score and FeNO significantly improves the diagnostic accuracy in childhood asthma.


Asunto(s)
Asma , Interleucina-33 , Niño , Humanos , Óxido Nítrico , Asma/diagnóstico , Pulmón , Curva ROC , Pruebas Respiratorias/métodos
6.
J. pediatr. (Rio J.) ; J. pediatr. (Rio J.);100(1): 81-87, 2024. tab, graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1528966

RESUMEN

Abstract Objective To investigate the diagnostic efficacy of serum IL-33 single indicator and combined indicators for asthma in children. Methods 132 children were initially diagnosed with asthma during acute exacerbation and 100 healthy children were included. Serum IL-33 concentration differences were compared between asthmatic and normal children. Correlations between IL-33 with pulmonary function parameters, FeNO, peripheral blood EOS counts and serum total IgE were analyzed in asthmatic children. ROC curves were used to assess IL-33 diagnostic efficacy and its combined indicators. To prevent overfitting of the predictive model, the hold-out cross-validation method was used. Results (1) Serum IL-33 concentrations were significantly higher in children with asthma than in normal children (p < 0.001). (2) IL-33 concentration was negatively correlated with FVC z-score, FEV1 z-score and FEF75% z-score in asthmatic children (p < 0.05). (3) The area under the ROC curve of IL-33 was 0.821, which was higher than those of FeNO, FVC z-score, and FEV1 z-score. (4) Cross-validation of the combined indicators showed that IL-33 significantly improved asthma diagnostic efficacy. The combination of IL-33, FEF75% z-score, and FeNO showed the highest diagnostic efficacy, with the AUC, sensitivity, and specificity of the combined indicator being 0.954, 90.1%, and 89. 0%, respectively, and good extrapolation of the predictive model. Conclusion Serum IL-33 is higher in children with asthma and increases with the severity of pulmonary ventilation obstruction. A single indicator of serum IL-33 demonstrates moderate diagnostic accuracy, and its combination with FEF75% z-score and FeNO significantly improves the diagnostic accuracy in childhood asthma.

7.
Int J Surg Case Rep ; 113: 109091, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38006738

RESUMEN

INTRODUCTION AND IMPORTANCE: Positioning nodule with a steel wire in pulmonary surgery is a common preoperative step. To date, no reports have been published on the retention of steel wires in the body post-surgery, nor have there been studies describing the ultrasound-guided removal of foreign objects from the chest wall. This report describes a case of a foreign matter was removed from the chest wall by ultrasound-guided. CASE PRESENTATION: A 70-year-old woman underwent thoracoscope resection of a pulmonary nodule; however, a fragment of the positioning steel wire remained in the chest wall during the surgery. The anesthetist located the residual steel wire using ultrasound, and subsequently, the surgeon successfully removed it. CLINICAL DISCUSSION: Detection of foreign matter in the body is rare and usually associated with trauma or accidental retention of materials such as absorbable gelatin sponges or sutures during surgery, which are often found using X-rays. This process is often time-consuming, and X-rays being radioactive are potentially harmful to patients and medical workers. Ultrasonic waves are safe and offer a convenient alternative for such procedures. We removed the residual steel wire through a 0.5 cm skin incision, this method neither caused trauma nor increased costs. CONCLUSION: Ultrasonography-assisted positioning is a rapid, convenient, and safe technique, promising to enhance future surgical interventions.

8.
Front Pediatr ; 11: 1189496, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37794961

RESUMEN

Objective: By examining fractional exhaled nitric oxide (FeNO) levels and performing pulmonary function testing, this study explored whether the multicenter study on the normal range of FeNO in children in China can be used to evaluate standardized treatment efficacy in 6- to 12-year-old children with asthma. Methods: A total of 115 children aged 6-12 years old who were first diagnosed with asthma and received standardized asthma treatment from April 2018 to July 2022 were selected. According to the FeNO level at the first visit, the subjects were divided into different high- and low-FeNO groups according to the American Thoracic Society (ATS) guidelines and the Chinese multicenter study recommendations. The consistency of the two grouping methods and the differences between the high- and low-FeNO groups were compared after standardized treatment. The grouping method that was the most suitable for children in the cross group was discussed. Results: (i) There was fair consistency between the Chinese multicenter study recommendations and the ATS guidelines regarding the classification of high- and low-FeNO groups (Kappa = 0.338). (ii) Repeated-measures ANOVA showed that the level of improvement in FVC%, FEV1%, FEF25%, FEF50%, and FeNO in the American high- and low-FeNO groups differed with the duration of therapy (P < 0.05), however, there was no significant difference between the Chinese groups. (iii) FEV1% and FeNO improved more after treatment in the fixed high-FeNO group than in the cross group (P < 0.05). Conclusion: The Chinese multicenter study on the normal range of FeNO in children in China has a limited role in evaluating standardized asthma treatment efficacy in 6- to 12-year-old children. The ATS guidelines are currently recommended for clinical assessment of asthma treatment efficacy.

9.
Drug Discov Today ; 27(5): 1236-1250, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-34971818

RESUMEN

The use of expedited approval pathways for anticancer drug development, which provide the advantages of high efficiency and cost-effectiveness, has expanded significantly in recent years. During the past decade, a total of 410 new molecular entities have been approved by the US Food and Drug Administration (FDA), with a steady growth of 6.5% in the US. In Europe, 9-75% of approved anticancer drugs were granted at least one expedited approval program. Various expedited pathways have also been implemented worldwide to address underrepresented medical needs rapidly. China has adapted several expedited approval programs, including breakthrough therapy designation, priority review, and conditional approval, to keep up with the growth in pharmaceutical development. It is expected that worldwide standards for drug approval will become more standardized in the next decade.


Asunto(s)
Antineoplásicos , Neoplasias , Antineoplásicos/uso terapéutico , Aprobación de Drogas , Desarrollo de Medicamentos , Neoplasias/tratamiento farmacológico , Producción de Medicamentos sin Interés Comercial , Estados Unidos , United States Food and Drug Administration
10.
ACS Nano ; 13(7): 8382-8391, 2019 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-31291085

RESUMEN

Creating long-lived topological textured liquid crystals (LCs) in confined nonspherical space is of significance in both generations of structures and fundamental studies of topological physics. However, it remains a great challenge due to the fluid character of LCs and the unstable tensional state of transient nonspheres. Here, we realize a rich series of topological textures confined in nonspherical geometries by drop impact assembly (DIA) of graphene oxide (GO) aqueous LCs. Various highly curved nonspherical morphologies of LCs were captured by gelator bath, generating distinct out-of-equilibrium yet long-lived macroscopic topological textures in 3D confinement. Our hydrodynamic investigations on DIA processes reveal that the shear-thinning fluid behavior of LCs and the arrested GO alignments mainly contribute to the topological richness in DIA. Utilizing the shaping behavior of GO LCs compared to other conventional linear polymers such as alginate, we further extend the DIA methodology to design more complex yet highly controllable functional composites and hybrids. This work thus reveals the potential to scale production of uniform yet anisotropic materials with rich topologic textures and tailored composition.

11.
Behav Brain Res ; 373: 112107, 2019 11 05.
Artículo en Inglés | MEDLINE | ID: mdl-31340174

RESUMEN

With the acceleration of an aging population, postoperative cognitive dysfunction (POCD) has become a large problem. Preoperative carbohydrate (CHO) loading has been reported to attenuate surgery stress response and insulin resistance. The present study aimed to investigate whether preoperative vitamin-rich CHO loading has an effect on POCD, endoplasmic reticulum (ER) stress, and apoptosis. Eighty male Sprague-Dawley rats (20-month old) were randomly assigned to four groups (20 per group): control group (no anesthesia and surgery), fasting group (fasting 14 h before surgery), water group (oral water 3 h before surgery), and CHO group (oral vitamin-rich CHO 3 h before surgery). The POCD rat model was established by splenectomy under intraperitoneal injection of pentobarbital sodium. Cognitive function was assessed using the Morris water maze (MWM) after surgery. The levels of endoplasmic reticulum (ER) stress markers and apoptosis related proteins in the hippocampus were examined by western blot analysis. The vitamin-rich CHO treated animals performed better in the MWM tests than the animals in the fasting and water groups. Furthermore, preoperative CHO loading reduced ER stress and neuronal apoptosis in the hippocampus of aged rats, as indicated by the protein biomarkers of GRP78, eIF2a, Beclin1, Bax, and Bcl-2. In conclusion, preoperative vitamin-rich CHO loading could improve POCD by attenuating ER stress and neural apoptosis, providing a basis as a potential treatment against POCD.


Asunto(s)
Carbohidratos/farmacología , Complicaciones Cognitivas Postoperatorias/dietoterapia , Factores de Edad , Animales , Apoptosis/efectos de los fármacos , Cognición/efectos de los fármacos , Disfunción Cognitiva/dietoterapia , Disfunción Cognitiva/metabolismo , Dieta de Carga de Carbohidratos/métodos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Ayuno , Hipocampo/metabolismo , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Complicaciones Posoperatorias/fisiopatología , Cuidados Preoperatorios/métodos , Ratas , Ratas Sprague-Dawley , Vitaminas/farmacología
12.
BMC Anesthesiol ; 19(1): 77, 2019 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-31092210

RESUMEN

BACKGROUND: Preoperative oral carbohydrates has been suggested to attenuate insulin resistance and decrease postoperative complications. In this study, a vitamin-rich carbohydrate beverage was administered before surgery in an animal model to investigate its effects on the surgical stress response and S-100ß levels. METHODS: Thirty aged male Sprague-Dawley rats were randomly assigned to three groups: control group (n = 6), fasting group (n = 12), and carbohydrate-treated group (CHO group, n = 12). Rats in the control group were not given any treatment. Rats in the fasting group received splenectomy after 12 h of fasting. In the CHO group, rats were given 5 ml of vitamin-rich carbohydrate by gavage 2 h before surgery. Fasting plasma glucose, insulin, insulin resistance (HOMA-IR index, IRI), the S-100ß protein level, and the inflammatory mediators IL-1ß, IL-6 and TNF-α were assessed after surgery (postoperative day (POD) 1 and 3). RESULTS: Postoperative insulin resistance was significantly greater in the fasting group than in the control and CHO group. The median plasma S-100ß level was significantly higher in the fasting group than in the control and CHO groups on POD 1. The median plasma IL-1ß level was significantly lower in the CHO group than in the fasting group on POD 1; however, no other differences in the concentrations of immunological biomarkers of stress were found between the fasting group and the CHO group. CONCLUSIONS: Vitamin-rich carbohydrate pretreatment attenuated the metabolic aspect of the surgical stress response and decreased the level of plasma S-100ß, which may decrease the risk of postoperative complications in elderly rats.


Asunto(s)
Envejecimiento/sangre , Carbohidratos de la Dieta/administración & dosificación , Dolor Postoperatorio/sangre , Subunidad beta de la Proteína de Unión al Calcio S100/sangre , Esplenectomía/efectos adversos , Vitaminas/administración & dosificación , Animales , Bebidas , Biomarcadores/sangre , Mediadores de Inflamación/antagonistas & inhibidores , Mediadores de Inflamación/sangre , Masculino , Dolor Postoperatorio/dietoterapia , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Subunidad beta de la Proteína de Unión al Calcio S100/antagonistas & inhibidores , Esplenectomía/tendencias , Resultado del Tratamiento
13.
Cyberpsychol Behav Soc Netw ; 21(6): 367-373, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29883207

RESUMEN

This study investigated the relationship between adolescents' problematic Internet use (PIU) and demographic characteristics such as age, gender, and information and communication technology (ICT) literacy and the moderating effect of geographic area on this relationship using a cross-sectional research design. The study sample comprised 2160 adolescents from the Chongqing area of China and consisted of 47.3 percent boys (N = 1022) and 52.7 percent girls (N = 1138). Participants anonymously completed a 38-item questionnaire that examined their Internet use, behaviors, and attitudes, ICT literacy, parents' education level, and other demographic information. The results showed that the geographic area in which respondents lived (urban vs. rural), gender, age, father's education, mother's education, and ICT literacy had significant relationships with PIU. Moreover, hierarchical multiple regression analyses indicated that geographic area was found to be a significant moderator for both age and gender in their relationship with PIU. These findings suggest that it is essential to address differences between urban and rural areas when seeking to mitigate PIU among adolescents.


Asunto(s)
Conducta del Adolescente , Conducta Adictiva/epidemiología , Alfabetización Digital/estadística & datos numéricos , Internet/estadística & datos numéricos , Adolescente , Factores de Edad , China/epidemiología , Estudios Transversales , Femenino , Geografía , Humanos , Masculino , Factores Sexuales
14.
Polymers (Basel) ; 9(10)2017 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-30965824

RESUMEN

Solvent vapor annealing of block copolymer (BCP) thin films can produce a range of interesting morphologies, especially when the perpendicular orientation of micro-domains with respect to the substrate plays a role. This, for instance, allows BCP thin films to serve as useful templates for nanolithography and hybrid materials preparation. However, precise control of the arising morphologies is essential, but in most cases difficult to achieve. In this work, we investigated the solvent and thickness effects on the morphology of poly(styrene-b-2 vinyl pyridine) (PS-b-P2VP) thin films with a film thickness range from 0.4 L0 up to 0.8 L0. Ordered perpendicular structures were achieved. One of the main merits of our work is that the phase behavior of the ultra-high molecular weight BCP thin films, which hold a 100-nm sized domain distance, can be easily monitored via current available techniques, such as scanning electron microscope (SEM), atomic force microscope (AFM), and transmission electron microscope (TEM). Systematic monitoring of the self-assembly behavior during solvent vapor annealing can thus provide an experimental guideline for the optimization of processing conditions of related BCP films systems.

15.
Medicine (Baltimore) ; 96(48): e8854, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29310366

RESUMEN

BACKGROUND: A solitary fibrous tumor (SFT) is a rare clinical tumor, often manifesting as solitary nodules. It is a rare condition that occurs in the scrotum. Currently, no study has reported this condition. CASE SUMMARY: We reported a case of an SFT in a 77-year-old man, and discuss its diagnosis, differential diagnosis, and treatment. Clinical and histopathological features, as well as the EnVision 2-step method, were used to diagnosis the SFT. The results of imaging tests and surgery indicated that the SFT was located in the right scrotum with 2 connected tumor nodules and a clear perimeter. The larger one was 11.0 cm × 9.3 cm × 8.1 cm, and the smaller one was 3.1 cm × 2.0 cm × 2.0 cm. Pathological results indicated that in both tumor nodules, tumor cells were spindle-shaped with unclear cell boundaries. The nucleus was vacuolated with mild to moderate atypia. In the larger tumor nodule, there were many thin-walled blood vessels with vasodilation or branching. In the smaller tumor nodule, rich blood vessels were found, mostly with fibrous degeneration of the thick walls of blood vessels, and more collagen-like tissue in the interstitial layers. Immunohistochemical results demonstrated diffuse, strongly positive expression of CD34, CD99, Vim, and Bcl-2 markers. The expression of the new fusion gene, NAB2-STAT6, as an alternative tool specifically confirmed the diagnosis of SFT. This patient underwent lump resection without further treatment. The patient is alive after 18-month follow-up. CONCLUSION: This case was diagnosed as a SFT according to its histopathological features, immunophenotype. The patient is still alive at 18 months follow-up after the lump resection.


Asunto(s)
Escroto/patología , Escroto/cirugía , Tumores Fibrosos Solitarios/patología , Anciano , Diagnóstico Diferencial , Humanos , Masculino , Tumores Fibrosos Solitarios/cirugía
16.
Biochem Biophys Res Commun ; 471(1): 198-204, 2016 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-26826388

RESUMEN

Abscisic acid (ABA) is an important phytohormone controlling seed dormancy. AFPs (ABA INSENSITIVE FIVE BINDING PROTEINS) are reported to be negative regulators of the ABA signaling pathway. The involvement of AFPs in dormant vegetative organs remains poorly understood. Here, we isolated and characterized a novel AFP family member from Gladiolus dormant cormels, GhAFP-like, containing three conserved domains of the AFP family. Quantitative PCR analysis revealed that GhAFP-like was expressed in dormant organs and its expression was down-regulated along with corm storage. GhAFP-like was verified to be a nuclear-localized protein. Overexpressing GhAFP-like in Arabidopsis thaliana not only showed weaker seed dormancy with insensitivity to ABA, but also changed the expression of some ABA related genes. In addition, a primary root elongation assay showed GhAFP-like may involve in auxin signaling response. The results in this study indicate that GhAFP-like acts as a negative regulator in ABA signaling and is related to dormancy.


Asunto(s)
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Iridaceae/fisiología , Fosfoproteínas Fosfatasas/metabolismo , Latencia en las Plantas/fisiología , Clonación Molecular , Germinación/fisiología , Tubérculos de la Planta
17.
Nanoscale ; 5(21): 10420-7, 2013 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-24056955

RESUMEN

In this study, we demonstrate a novel fabrication method to prepare metallic Janus silica particles by embedding nanosized silica particles on a spherical polystyrene (PS) substrate in supercritical carbon dioxide (sc CO2), followed by labelling with gold nanoparticles on the exposed part of the silica colloids. To this end, three main types of Janus particles displaying two distinct surfaces are produced by recovering silica from the polystyrene template. Embedment of particles into the PS template in sc CO2 allows for precise control of the degree of embedding of particles and subsequent modification of the partially exposed particle surface. The embedding degree, as well as the final Janus balance, can be varied over a wide range through control of pressure, temperature, or treatment time of sc CO2. Hierarchical PS-silica composites and embedment are evaluated by scanning electron microscopy (SEM). Partial surface modification with gold nanoparticles is investigated by transmission electron microscopy (TEM). With this method various functionalized Janus particles with tuneable properties can be prepared by adjusting various surface modifiers and polymer substrates in the future.

18.
J Colloid Interface Sci ; 358(2): 437-43, 2011 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-21463865

RESUMEN

In this paper, monodisperse poly(styrene-co-divinylbenzene) (PS-DVB) capsules with a bowl-like morphology were prepared controllably by regulating the content of DVB and dispersant. Using as-prepared PS-DVB capsules as building blocks, two-dimensional (2D) uniform hexagonal close-packed array with same orientation of each bowl was successfully fabricated by solvent evaporation. The size distribution showed that the capsules were still spherical in acetone before assembly and thus certified that the capsules caved in after self-assembly. Many factors including DVB content in capsules, experimental temperature and dispersants play important roles on regularity of orientation. Besides, "local self-assembly" array using multi-caved capsule as building blocks was obtained. More study proceeds with it, further advanced materials with complex functionalities or peculiar behavior could be expected.

19.
World J Microbiol Biotechnol ; 27(6): 1381-9, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25187137

RESUMEN

This study focused on enhancing the bioremediation of soil contaminated with viscous oil by microorganisms and evaluating two strategies. Construction of microbial consortium and ultraviolet mutation were both effective applications in the remediation of soil contaminated with viscous oil. Results demonstrated that an interaction among the microorganisms existed and affected the biodegradation rate. Strains inoculated equally into the test showed the best remediation, and an optimal microbial consortium was achieved with a 7 days' degradation rate of 49.22%. On the other hand, the use of ultraviolet mutation increased one strain's degrading ability from 41.83 to 52.42% in 7 days. Gas chromatography and mass spectrum analysis showed that microbial consortium could treat more organic fractions of viscous oil, while ultraviolet mutation could be more effect on increasing one strain's degrading ability.

20.
Acta Crystallogr C ; 64(Pt 10): m349-52, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18838769

RESUMEN

The asymmetric unit of the title compound, {[Cu(CO(3))(C(14)H(14)N(4))(1.5)] x 0.5 C(14)H(14)N(4) x 5 H(2)O}(n), contains one Cu(II) cation in a slightly distorted square-pyramidal coordination environment, one CO(3)(2-) anion, one full and two half 1,4-bis(imidazol-1-ylmethyl)benzene (bix) ligands, one half-molecule of which is uncoordinated, and five uncoordinated water molecules. One of the coordinated bix ligands and the uncoordinated bix molecule are situated about centers of symmetry, located at the centers of the benzene rings. The coordinated bix ligands link the copper(II) ions into a [Cu(bix)(1.5)](n) molecular ladder. These molecular ladders do not form interpenetrated ladders but are arranged in an ABAB parallel terrace, i.e. with the ladders arranged one above another, with sequence A translated with respect to B by 8 A. To best of our knowledge, this arrangement has not been observed in any of the molecular ladder frameworks synthesized to date. The coordination environment of the Cu(II) atom is completed by two O atoms of the CO(3)(2-) anion. The framework is further strengthened by extensive O-H...O and O-H...N hydrogen bonds involving the water molecules, the O atoms of the CO(3)(2-) anion and the N atoms of the bix ligands. This study describes the first example of a molecular ladder coordination polymer based on bix and therefore demonstrates further the usefulness of bix as a versatile multidentate ligand for constructing coordination polymers with interesting architectures.

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