446 research outputs found
Palliative care of children with brain tumors: A parental perspective
Objective: To explore the end-of-life experience of children with brain tumors and their families. Design: Qualitative analysis of focus group interviews. Setting: Children\u27s Hospital, London Health Sciences Center. Participants: Twenty-five parents of 17 children who had died of brain tumors. Intervention: Parents participated in 3 semistructured focus group interviews. Main Outcome Measures: Themes identified through thematic analysis of interview transcripts. Results: Qualitative analysis identified 3 primary themes. (1) Parents described the dying trajectory of their child as characterized by progressive neurologic deterioration, with the loss of the ability to communicate as a turning point. Parental coping mechanisms included striving to maintain normality and finding spiritual strength through maintaining hope and in the resilience of their child. (2) Parental struggles during this phase included balancing competing responsibilities and speaking with their child about death. (3) Barriers to achieving a home death included suboptimal symptom management, financial and practical hardships, and inadequate community support. A fourth, secondary theme concerned the therapeutic benefits of the interview. Conclusion: The neurologic deterioration that characterizes the dying trajectory of children with brain tumors may create significant challenges for health care professionals and the children\u27s parents, supporting the need for increased awareness of the distinct issues in the palliative care of children with brain tumors and for early anticipatory guidance provided for families. ©2010 American Medical Association. All rights reserved
One-pot synthesis of silica monoliths with hierarchically porous structure
Poly(furfuryl alcohol) (PFA) and block copolymer Pluronic F127 were used as pore templates to create mechanically robust silica monoliths with a hierarchical and interconnected macro?mesoporous network in an easy, reproducible bimodal scale templating process. Control over the morphology was obtained by varying the reactant ratios. Phase separation on the submicrometer scale occurred when furfuryl alcohol was cationically polymerized and therefore became immiscible with the solvent and the silica precursor. Upon a subsequent sol?gel reaction, a silica-F127 matrix formed around the PFA spheres, leading to macropore structures with mesoporous walls. Surface areas of the final structures ranged from 500 to 989 m2/g and a maximum pore volume of 4.5 mL/g was achieved. Under mildly acidic conditions, micelle-templated mesopores resulted. Interconnected macropores could be obtained by increasing the pH or the block copolymer concentration. The formation mechanism and the relationship between PFA, Pluronic F127 and acidity are discussed in detail.Fil: Drisko, Glenna L.. University of Melbourne; AustraliaFil: Zelcer, Andrés. Universidad Nacional de San MartÃn. Escuela de Ciencia y TecnologÃa; Argentina. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Caruso, Rachel A.. University of Melbourne; AustraliaFil: Soler Illia, Galo Juan de Avila Arturo. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentin
One-pot synthesis of hierarchically structured ceramic monoliths with adjustable porosity
Hierarchically porous oxides are used in a variety of applications within the energy sector (e.g., fuel cells, batteries), biology (e.g., scaffolds, biocatalysis), separations, and catalysis. This article describes a reproducible one-step method for the preparation of metal oxides with controllable hierarchical pore architectures. The preparation is demonstrated for a wide range of materials, specifically silica, titania, zirconia, aluminum titanium oxide, titanium zirconium oxide, and yttrium zirconium oxide monoliths. The samples were prepared by exploiting the polymerization and phase separation of furfuryl alcohol to produce a colloidal dispersion of poly(furfuryl alcohol) particles. The gelation in the sol-gel process occurred after the in situ formation of the template. The removal of the polymer template led to the formation of macropores, whereas inclusion of an amphiphilic block copolymer (Pluronic F127) assisted mesopore formation, either by templating or by stabilizing the inorganic building blocks. The macropore and mesopore morphology could be altered by varying the synthesis conditions. This control over the pore structure was demonstrated in the silica, titania, and titanium zirconium oxide materials.Fil: Drisko, Glenna L.. University of Melbourne; AustraliaFil: Zelcer, Andrés. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Luca, Vittorio. Comisión Nacional de EnergÃa Atómica; ArgentinaFil: Caruso, Rachel A.. University of Melbourne; AustraliaFil: Soler Illia, Galo Juan de Avila Arturo. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Synthesis and photocatalytic activity of titania monoliths prepared with controlled macro- and mesopore structure
Herein, we report a one-pot synthesis of crack-free titania monoliths with hierarchical macro-mesoporosity and crystalline anatase walls. Bimodal macroporosity is created through the polymer-induced phase separation of poly(furfuryl alcohol). The cationic polymerization of furfuryl alcohol is performed in situ and subsequently the polymer becomes immiscible with the aqueous phase, which includes titanic acid. Addition of template, Pluronic F127, increases the mesopore volume and diameter of the resulting titania, as the poly(ethylene glycol) block interacts with the titania precursor, leading to assisted assembly of the metal oxide framework. The hydrophobic poly(propylene glycol) micelle core could itself be swollen with monomeric and oligomeric furfuryl alcohol, allowing for mesopores as large as 18 nm. Variations in synthesis parameters affect porosity; for instance furfuryl alcohol content changes the size and texture of the macropores, water content changes the grain size of the titania and Pluronic F127 content changes the size and volume of the mesopore. Morphological manipulation improves the photocatalytic degradation of methylene blue. Light can penetrate several millimeters into the porous monolith, giving these materials possible application in commercial devices.Fil: Drisko, Glenna L.. University of Melbourne; AustraliaFil: Zelcer, Andrés. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad Nacional de San MartÃn. Escuela de Ciencia y TecnologÃa; ArgentinaFil: Wang, Xingdong. Commonwealth Scientific And Industrial Research Organization; AustraliaFil: Caruso, Rachel A.. School Of Chemistry; Australia. Commonwealth Scientific And Industrial Research Organization; AustraliaFil: Soler Illia, Galo Juan de Avila Arturo. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Desarrollo de Reactores Basados en PelÃculas de Materiales Mesoporosos para la Destrucción De Nitratos Disueltos en Agua
Se sintetizaron y estudiaron films mesoporosos de TiO2 para la eliminación fotocatalÃtica de nitratos disueltos en agua. Los filmes se prepararon sobre sustratos de vidrio, combinando reacciones sol - gel y Autoensamblado Inducido por Evaporación y se caracterizaron estructuralmente por diversas técnicas. Se estudió el efecto del grosor, de la introducción de nanopartÃculas de plata y del dopaje con bismuto en la ca pacidad fotocatalÃtica. Los films más efectivos para realizar fotocatálisis y eliminar nitratos fueron aquellos a los cuales se introdujeron nanopartÃculas de plata, los cuales poseen una capacidad de eliminar nitratos de alrededor de 7,2 ppm/cm2 h.Mesoporous TiO2 films for the photocatalytic elimination of nitrates dissolved in water were synthesized and studied. The films were prepared on glass substrates by combining sol-gel reactions and evaporation-induced self-assembly and they were characterized structurally by various techniques. The effect of thickness, the introduction of nanoparticles of silver and bismuth doping on the photocatalytic ability were studied. The most effective films for photocatalysis and remove nitrates were those which were made of silver nanoparticles, which have a capacity to remove nitrates from about 7.2 ppm/cm2h.Fil: Zambrano, S. M.. Comisión Nacional de EnergÃa Atómica; ArgentinaFil: Zelcer, A.. Comisión Nacional de EnergÃa Atómica; ArgentinaFil: Bellino, Martin Gonzalo. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Desarrollo de Reactores Basados en PelÃculas de Materiales Mesoporosos para la Destrucción De Nitratos Disueltos en Agua
Se sintetizaron y estudiaron films mesoporosos de TiO2 para la eliminación fotocatalÃtica de nitratos disueltos en agua. Los filmes se prepararon sobre sustratos de vidrio, combinando reacciones sol - gel y Autoensamblado Inducido por Evaporación y se caracterizaron estructuralmente por diversas técnicas. Se estudió el efecto del grosor, de la introducción de nanopartÃculas de plata y del dopaje con bismuto en la ca pacidad fotocatalÃtica. Los films más efectivos para realizar fotocatálisis y eliminar nitratos fueron aquellos a los cuales se introdujeron nanopartÃculas de plata, los cuales poseen una capacidad de eliminar nitratos de alrededor de 7,2 ppm/cm2 h.Mesoporous TiO2 films for the photocatalytic elimination of nitrates dissolved in water were synthesized and studied. The films were prepared on glass substrates by combining sol-gel reactions and evaporation-induced self-assembly and they were characterized structurally by various techniques. The effect of thickness, the introduction of nanoparticles of silver and bismuth doping on the photocatalytic ability were studied. The most effective films for photocatalysis and remove nitrates were those which were made of silver nanoparticles, which have a capacity to remove nitrates from about 7.2 ppm/cm2h.Fil: Zambrano, S. M.. Comisión Nacional de EnergÃa Atómica; ArgentinaFil: Zelcer, A.. Comisión Nacional de EnergÃa Atómica; ArgentinaFil: Bellino, Martin Gonzalo. Comisión Nacional de EnergÃa Atómica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
CAMKII Activation Is Not Required for Maintenance of Learning-Induced Enhancement of Neuronal Excitability
Pyramidal neurons in the piriform cortex from olfactory-discrimination trained rats show enhanced intrinsic neuronal excitability that lasts for several days after learning. Such enhanced intrinsic excitability is mediated by long-term reduction in the post-burst after-hyperpolarization (AHP) which is generated by repetitive spike firing. AHP reduction is due to decreased conductance of a calcium-dependent potassium current, the sIAHP. We have previously shown that learning-induced AHP reduction is maintained by persistent protein kinase C (PKC) and extracellular regulated kinase (ERK) activation. However, the molecular machinery underlying this long-lasting modulation of intrinsic excitability is yet to be fully described. Here we examine whether the CaMKII, which is known to be crucial in learning, memory and synaptic plasticity processes, is instrumental for the maintenance of learning-induced AHP reduction. KN93, that selectively blocks CaMKII autophosphorylation at Thr286, reduced the AHP in neurons from trained and control rat to the same extent. Consequently, the differences in AHP amplitude and neuronal adaptation between neurons from trained rats and controls remained. Accordingly, the level of activated CaMKII was similar in pirifrom cortex samples taken form trained and control rats. Our data show that although CaMKII modulates the amplitude of AHP of pyramidal neurons in the piriform cortex, its activation is not required for maintaining learning-induced enhancement of neuronal excitability
Defective Lipid Droplet-Lysosome Interaction Causes Fatty Liver Disease as Evidenced by Human Mutations in TMEM199 and CCDC115
BACKGROUND & AIMS: Recently, novel inborn errors of metabolism were identified because of mutations in V-ATPase assembly factors TMEM199 and CCDC115. Patients are characterized by generalized protein glycosylation defects, hypercholesterolemia, and fatty liver disease. Here, we set out to characterize the lipid and fatty liver phenotype in human plasma, cell models, and a mouse model.METHODS AND RESULTS: Patients with TMEM199 and CCDC115 mutations displayed hyperlipidemia, characterized by increased levels of lipoproteins in the very low density lipoprotein range. HepG2 hepatoma cells, in which the expression of TMEM199 and CCDC115 was silenced, and induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells from patients with TMEM199 mutations showed markedly increased secretion of apolipoprotein B (apoB) compared with controls. A mouse model for TMEM199 deficiency with a CRISPR/Cas9-mediated knock-in of the human A7E mutation had marked hepatic steatosis on chow diet. Plasma N-glycans were hypogalactosylated, consistent with the patient phenotype, but no clear plasma lipid abnormalities were observed in the mouse model. In the siTMEM199 and siCCDC115 HepG2 hepatocyte models, increased numbers and size of lipid droplets were observed, including abnormally large lipid droplets, which colocalized with lysosomes. Excessive de novo lipogenesis, failing oxidative capacity, and elevated lipid uptake were not observed. Further investigation of lysosomal function revealed impaired acidification combined with impaired autophagic capacity.CONCLUSIONS: Our data suggest that the hyperchole-sterolemia in TMEM199 and CCDC115 deficiency is due to increased secretion of apoB-containing particles. This may in turn be secondary to the hepatic steatosis observed in these patients as well as in the mouse model. Mechanistically, we observed impaired lysosomal function characterized by reduced acidification, autophagy, and increased lysosomal lipid accumulation. These findings could explain the hepatic steatosis seen in patients and highlight the importance of lipophagy in fatty liver disease. Because this pathway remains understudied and its regulation is largely untargeted, further exploration of this pathway may offer novel strategies for therapeutic interventions to reduce lipotoxicity in fatty liver disease.</p
Machine Learning Identifies Clinical and Genetic Factors Associated With Anthracycline Cardiotoxicity in Pediatric Cancer Survivors
BACKGROUND Despite known clinical risk factors, predicting anthracycline cardiotoxicity remains challenging. OBJECTIVES This study sought to develop a clinical and genetic risk prediction model for anthracycline cardiotoxicity in childhood cancer survivors. METHODS We performed exome sequencing in 289 childhood cancer survivors at least 3 years from anthracycline exposure. In a nested case-control design, 183 case patients with reduced left ventricular ejection fraction despite low-dose doxorubicin (\u3c= 250 mg/m(2)), and 106 control patients with preserved left ventricular ejection fraction despite doxorubicin \u3e250 mg/m(2) were selected as extreme phenotypes. Rare/low-frequency variants were collapsed to identify genes differentially enriched for variants between case patients and control patients. The expression levels of 5 top-ranked genes were evaluated in human induced pluripotent stem cell-derived cardiomyocytes, and variant enrichment was confirmed in a replication cohort. Using random forest, a risk prediction model that included genetic and clinical predictors was developed. RESULTS Thirty-one genes were differentially enriched for variants between case patients and control patients (p \u3c 0.001). Only 42.6% case patients harbored a variant in these genes compared to 89.6% control patients (odds ratio: 0.09; 95% confidence interval: 0.04 to 0.17; p = 3.98 x 10(-15)). A risk prediction model for cardiotoxicity that included clinical and genetic factors had a higher prediction accuracy and lower misclassification rate compared to the clinical-only model. In vitro inhibition of gene-associated pathways (PI3KR2, ZNF827) provided protection from cardiotoxicity in cardiomyocytes. CONCLUSIONS Our study identified variants in cardiac injury pathway genes that protect against cardiotoxicity and informed the development of a prediction model for delayed anthracycline cardiotoxicity, and it also provided new targets in autophagy genes for the development of cardio-protective drugs
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