Search results for "loss"

Structural and Chemical Characterization of Cerium Oxide Thin Layers Grown on Silicon Substrate

2015

In this study, we report transmission electron microscopy and electron energy loss spectroscopy study of cerium oxide thin layers deposited on silicon substrate. Transmission electron microscopy experiments have revealed the flat morphology of the deposited layers. In addition, studies of high resolution images have indicated the presence of mainly ceria crystallized nanoparticles. Energy electron loss spectroscopy measurements were also performed in scanning mode to study the evolution of the cerium valence. In addition to Ce4+ inside the layer, the presence of amorphous cerium silicate with valence +3 is pointed out at the vicinity of the substrate.

Growth and composition of nanostructured and nanoporous cerium oxide thin films on a graphite foil.

2015

The morphology and composition of CeOx films prepared by r.f. magnetron sputtering on a graphite foil have been investigated mainly by using microscopy methods. This study presents the formation of nanocrystalline layers with porous structure due to the modification of a carbon support and the formation of cerium carbide crystallites as a result of the deposition process. Chemical analyses of the layers with different thicknesses performed by energy dispersive X-ray spectroscopy, electron energy loss spectroscopy and X-ray photoelectron spectroscopy have pointed to the reduction of the cerium oxide layers. In the deposited layers, cerium was present in mixed Ce(3+) and Ce(4+) valence. Ce(3+…

Mechanical performance of experimental acrylic resins modified by nanoparticles after chemical and mechanical degradation.

2020

Background Different materials have been incorporated into the polymethylmethacrylate matrix to improve its performance. The aim of this study was to evaluate the degree of conversion (DC), the flexural strength (FS), the elasticity modulus (EM), and the effect of exposure to food-simulating liquids prior to brushing simulation on the gloss loss (GL) of experimental acrylic resins modified by nanoparticles. Material and methods Three different types of nanoparticles; silicon oxide (SiO2), cerium oxide (CeO2) and titanium oxide (TiO2) were added to a poly (methylmethacrylate) matrix, in proportions of 0.5wt%, 1wt% and 3wt% each, forming nine experimental groups. The acrylic resin was also te…

On groups having a p-constant character

2020

Let G G be a finite group, and p p a prime number; a character of G G is called p p -constant if it takes a constant value on all the elements of G G whose order is divisible by p p . This is a generalization of the very important concept of characters of p p -defect zero. In this paper, we characterize the finite p p -solvable groups having a faithful irreducible character that is p p -constant and not of p p -defect zero, and we will show that a non- p p -solvable group with this property is an almost-simple group.

Structure of doped polyaniline - dielectric spectroscopy measurements

1993

The role of doping reagents (residual water and acid anions) in determining the electric properties of a chemically synthesized polyaniline (PANI) was studied using a dielectric spectroscopy method. Dependencies of dielectric losses and susceptibility of PANI as the functions of temperature (-100÷+100°C) and electric field frequency (0.3÷30000 Hz) were examined at it was shown the role of water acts as a doping impurity similar to acid anions. The model is proposed to explain the role of water in terms of adsorption of H 2 O molecules at nitrogen sites of PANI chain and their dissociation

Key Ingredients for Mastery of Chemical Microwave Processes

2012

Influence of gel composition in the synthesis of MoVTeNb catalysts over their catalytic performance in partial propane and propylene oxidation

2010

[EN] MoVTeNb mixed oxides catalysts have been prepared by a slurry method with different molar compositions (Mo/Te ratio from 2 to 6 and Nb/(V + Nb) ratio from 0 to 0.7) in the synthesis gel leading to different crystalline phases distribution and catalytic behaviour in the partial oxidation of both propane and propylene to acrylic acid. Chemical analysis indicates that the composition of samples before and after the heat-treatment changes, especially the Te-content, since a significant amount of Te is lost during the heat-treatment step when the amount of oxalate (from niobium oxalate) increases in the synthesis gel. Thus, the nature of the crystalline phases and the catalytic performance …

Bone damage after chemotherapy for lymphoma: a real-world experience

2021

AbstractBackgroundDespite recent improvements in survival due to advances in treatment, the quality of life of patients with lymphoma may be compromised by the long-term complications of chemotherapy and steroid therapy. Among these, a potentially relevant problem is bone loss and the development of fragility fractures.AimTo provide further evidence of clinical or subclinical skeletal complications in correlation with biological variables and markers of bone disease in patients with complete response to therapy.MethodA cross-sectional observational study was conducted on subjects diagnosed with lymphoma with subsequent antineoplastic treatment, disease status after therapy defined as comple…

Medikamentöse Therapie progredienter kindlicher Hörstörungen

1991

In 1987 and 1988 Nickisch et al. discussed the effect of infusions of prednisolone, pentoxifylline and, partially, piracetam in Ringer lactate solvent on progressive sensorineural hearing loss in childhood and adolescence. Time of observations was 4 years. Unfortunately long-term investigations could not confirm the initially good therapeutic results of 1987/88. In 35% were found permanently and in 12.5% temporarily better auditory thresholds after infusion. The loss of progressive sensorineural hearing in childhood usually takes a fateful course that can hardly be influenced. As is the case with adults, good therapeutic results can most probably be achieved by infusions starting close to t…

Predictors of mucositis in oropharyngeal and oral cavity cancer in patients treated with volumetric modulated radiation treatment: A dose-volume anal…

2015

Background The purpose of this study was to assess predictors of mucositis in oropharyngeal and oral cavity cancer after definitive or adjuvant volumetric modulated arc radiotherapy (VMAT) +/− chemotherapy. Methods Fifty patients were evaluated. Statistical analysis was performed for the following parameters as potential predictors of mucositis ≥ G2: total oral mucosa and oral mucosa minus target high-low radiation dose regions (planning target volumes [PTVs]), mean dose (Dmean), maximum dose (Dmax), chemotherapy, weight loss, and dysphagia. Results Mucositis ≥ G2 was found to be statistically related to chemotherapy, weight loss, dysphagia ≥ G2, total oral mucosa Dmean ≥50 Gy and Dmax ≥65 …