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1.
Nanotechnology ; 35(32)2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38710177

RESUMO

This study investigates the fabrication process of copper thin films via thermal evaporation, with precise control over film thickness achieved throughZ-position adjustment. Analysis of the as-fabricated copper films reveals a discernible relationship between grain size (〈D〉) andZ-position, characterized by a phenomenological equation〈D〉XRDn(Z)=〈D〉0n1+32rZ2+158rZ4, which is further supported by a growth exponent (n) of 0.41 obtained from the analysis. This value aligns well with findings in the literature concerning the growth of copper films, thus underlining the validity and reliability of our experimental outcomes. The resulting crystallites, ranging in size from 20 to 26 nm, exhibit a resistivity within the range of 3.3-4.6µΩ · cm. Upon thermal annealing at 200 °C, cuprite Cu2O thin films are produced, demonstrating crystallite sizes ranging from ∼9 to ∼24 nm with increasing film thickness. The observed monotonic reduction in Cu2O crystallites relative to film thickness is attributed to a recrystallization process, indicating amorphization when oxygen atoms are introduced, followed by the nucleation and growth of newly formed copper oxide phase. Changes in the optical bandgap of the Cu2O films, ranging from 2.31 to 2.07 eV, are attributed mainly to the quantum confinement effect, particularly important in Cu2O with size close than the Bohr exciton diameter (5 nm) of the Cu2O. Additionally, correlations between refractive index and extinction coefficient with film thickness are observed, notably a linear relationship between refractive index and charge carrier density. Electrical measurements confirm the presence of a p-type semiconductor with carrier concentrations of ∼1014cm-3, showing a slight decrease with film thickness. This phenomenon is likely attributed to escalating film roughness, which introduces supplementary scattering mechanisms for charge carriers, leading to a resistivity increase, especially as the roughness approaches or surpasses the mean free path of charge carriers (8.61 nm). Moreover,ab-initiocalculations on the Cu2O crystalline phase to investigate the impact of hydrostatic strain on its electronic and optical properties was conducted. We believe that our findings provide crucial insights that support the elucidation of the experimental results. Notably, thinner cuprite films exhibit heightened sensitivity to ethanol gas at room temperature, indicating potential for highly responsive gas sensors, particularly for ethanol breath testing, with significant implications for portable device applications.

2.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-38677470

RESUMO

The main event of osteoporosis is fragility fractures. Vertebral compression fractures are the most commonly fragility fracture related to osteoporosis. Our goal is to review the available literature to confirm or deny concepts learned about spinal cementation and adapt our clinical practice according to scientific evidence. In the complex world of spine surgery, constant innovations seek to improve the quality of life of patients. Among these, vertebral augmentation has emerged as an increasingly popular technique, but often shrouded in myths and misunderstandings. In this systematic review, we will thoroughly explore the truths behind vertebral augmentation, unraveling common myths and providing a clear insight into this technique. As specialists in the field, it is crucial to understand the reality surrounding these interventions to offer our patients the best possible information and make informed decisions.

3.
RSC Adv ; 13(41): 28482-28492, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37771926

RESUMO

Nowadays, the use of self-cleaning surfaces is increasing globally, especially after the COVID-2019 pandemic, and the use of nanoparticles has been shown as a plausible option for this purpose. In the present study, Cu-doped SnO2 nanocrystals were successfully synthesized (in the copper content range of 0-30 mol%) using the polymeric precursor method. The structural, morphological, vibrational, and antibacterial activity were carefully studied to unveil the effect of copper ions on the properties of the hosting matrix, aiming at maximizing the usage of Cu-doped SnO2 nanocrystals. The results show fabrication of nanoparticles near their respective exciton Bohr diameter (5.4 nm for SnO2), however, monophasic SnO2 was observed up to 15 mol%. Above this limit, a secondary CuO phase was observed, as shown by the assessed X-ray diffraction (XRD), Fourier transform infrared, and Raman spectroscopy data. Furthermore, the redshift of the primary A1g vibrational mode of SnO2 is successfully described using the phonon-confinement model, demonstrating a good relationship between the Raman correlation length (L) and the crystallite size (〈D〉), the latter determined from XRD. Regarding the antibacterial activity, assessed via the disc-diffusion testing method (DDTM) while challenging two bacterial species (S. aureus and E. coli), our results suggest a rapid diffusion of the nanoparticles out of the paper disc, with a synergistic effect credited to the Sn1-xCuxO2-CuO phases contributing to the inhibition of the bacteria growth. Moreover, the DDTM data scales with cell viability, the latter analyzed using the Hill equation, from which both lethal dose 50 (LD50) and benchmark dose (BMD) were extracted.

4.
J Environ Health Sci Eng ; 20(2): 849-860, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36406591

RESUMO

Water is an essential compound on earth and necessary for life. The presence of highly toxic contaminants such as arsenic and others, in many cases, represents one of the biggest problems facing the earth´s population. Treatment of contaminated water with magnetite (Fe3O4) nanoparticles (NPs) can play a crucial role in arsenic removal. In this report, we demonstrate arsenic removal from an aqueous solution and natural water taken from the Peruvian river (Tambo River in Arequipa, Peru) using magnetite NPs synthesized by the coprecipitation method. XRD data analysis of Fe3O4 NPs revealed the formation of the cubic-spinel phase of magnetite with an average crystallite size of ~ 13 nm, which is found in good agreement with the physical size assessed from TEM image analysis. Magnetic results evidence that our NPs show a superparamagnetic-like behavior with a thermal relaxation of magnetic moments mediated by strong particle-particle interactions. FTIR absorption band shows the interactions between arsenate anions and Fe-O and Fe-OH groups through a complex mechanism. The experimental results showed that arsenic adsorption is fast during the first 10 min; while the equilibrium is reached within 60 min, providing an arsenic removal efficiency of ~ 97%. Adsorption kinetics is well modeled using the pseudo-second-order kinetic equation, suggesting that the adsorption process is related to the chemisorption model. According to Langmuir's model, the maximum arsenic adsorption capacity of 81.04 mg·g- 1 at pH = 2.5 was estimated, which describes the adsorption process as being monolayer, However, our results suggest that multilayer adsorption can be produced after monolayer saturation in agreement with the Freundlich model. This finding was corroborated by the Sips model, which showed a good correlation to the experimental data. Tests using natural water taken from Tambo River indicate a significant reduction of arsenic concentration from 356 µg L- 1 to 7.38 µg L- 1, the latter is below the limit imposed by World Health Organization (10 µg L- 1), suggesting that magnetite NPs show great potential for the arsenic removal.

5.
Arch Soc Esp Oftalmol (Engl Ed) ; 97(4): 184-190, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35523464

RESUMO

BACKGROUND AND OBJECTIVE: The SARS-CoV-2 pandemic has caused chaos in all health systems on the planet. It has been difficult to cope with COVID 19, but also to maintain the activity in other specialties. In ophthalmology, the scientific societies recommended providing urgent care, including the intravitreal treatment of patients with active neovascular age-related macular degeneration (AMD), since a delay in treatment implies a potential loss of visual acuity (VA). The main objective of this study was to measure the impact of the coronavirus lockdown on the activity and visual results in patients with neovascular AMD in Area 3 of Madrid. MATERIAL AND METHOD: A retrospective observational study was conducted of all patients with neovascular AMD who attended a consultation and/or received intravitreal treatment in the 3 months before the lockdown. RESULTS: In the 3 months before the lockdown, 144 patients with neovascular AMD were treated, of whom only 51 attended a consultation during the lockdown and, at 6 months after it, only 117 patients had resumed their follow-up. Mean VA before the lockdown was 58.0 ±â€¯23.7 letters and was statistically significantly reduced to 53.0 ±â€¯27.1 letters at 6 months after the lockdown. We also observed a significant decrease in the number of visits during the lockdown, despite the security measures implemented. CONCLUSIONS: Our study shows that patients with neovascular AMD have had a statistically significant decrease in VA due to the lockdown. A VA of almost 58 letters was reduced to 53 at 6 months after the lockdown. The percentage of patients who lost 15 or more letters doubled. We observed a 63.3% loss of temporary follow-up during the lockdown and a 14.58% loss of permanent follow-up at 6 months after the lockdown.


Assuntos
COVID-19 , Degeneração Macular Exsudativa , Inibidores da Angiogênese/uso terapêutico , Controle de Doenças Transmissíveis , Humanos , Injeções Intravítreas , Pandemias , SARS-CoV-2 , Fator A de Crescimento do Endotélio Vascular , Acuidade Visual , Degeneração Macular Exsudativa/tratamento farmacológico
6.
Arch Soc Esp Oftalmol ; 97(4): 184-190, 2022 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-34876774

RESUMO

Background and objective: The SARS-CoV-2 pandemic has caused chaos in all health systems on the planet. It has been difficult to cope with COVID 19, but also to maintain the activity in other specialties. In ophthalmology, the scientific societies recommended providing urgent care, including the intravitreal treatment of patients with active neovascular age-related macular degeneration (AMD), since a delay in treatment implies a potential loss of visual acuity (VA).The main objective of this study was to measure the impact of the coronavirus lockdown on the activity and visual results in patients with neovascular AMD in Area 3 of Madrid. Material and method: A retrospective observational study was conducted of all patients with neovascular AMD who attended a consultation and/or received intravitreal treatment in the 3 months before the lockdown. Results: In the 3 months before the lockdown, 144 patients with neovascular AMD were treated, of whom only 51 attended a consultation during the lockdown and, at 6 months after it, only 117 patients had resumed their follow-up. Mean VA before the lockdown was 58.0 ± 23.7 letters and was statistically significantly reduced to 53.0 ± 27.1 letters at 6 months after the lockdown. We also observed a significant decrease in the number of visits during the lockdown, despite the security measures implemented. Conclusions: Our study shows that patients with neovascular AMD have had a statistically significant decrease in VA due to the lockdown. A VA of almost 58 letters was reduced to 53 at 6 months after the lockdown. The percentage of patients who lost 15 or more letters doubled. We observed a 63.3% loss of temporary follow-up during the lockdown and a 14.58% loss of permanent follow-up at 6 months after the lockdown.

7.
Nanoscale Adv ; 3(5): 1484-1495, 2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-36132869

RESUMO

During the last decade, there was a substantial increase in the research on metal-doped oxide semiconductor nanoparticles due to advances in the engineering of nanomaterials and their potential application in spintronics, biomedicine and photocatalysis fields. In this regard, doping a nanomaterial is a powerful tool to tune its physicochemical properties. The aim of this work is to shine a new light on the role of the neighbouring elements on the oxidation state of the Ce-impurity, from both experimental and theoretical points of view. Herein, we present an accurate study of the mechanisms involved in the oxidation states of the Ce-ions during the doping process of SnO2 nanoparticles (NPs) prepared by the polymeric precursor method. X-ray diffraction measurements have displayed the tetragonal rutile-type SnO2 phase in all samples. However, the Bragg's peak (111) and (220) located at 2θ ∼29° and ∼47° evidence the formation of a secondary CeO2 phase for samples with Ce content up to 10%. X-ray absorption near-edge structure (XANES) measurements, at Ce L3 edge, were performed on the NPs as a function of Ce content. The results show, on one side, the coexistence of Ce3+ and Ce4+ states in all samples; and on the other side, a clear reduction in the Ce3+ population driven by the increase of Ce content. It is shown that this is induced by the neighboring cation, and confirmed by magnetic measurements. The monotonic damping of the Ce3+/Ce4+ ratio experimentally, was connected with theoretical calculations via density functional theory by simulating a variety of point defects composed of Ce impurities and surrounding oxygen vacancies. We found that the number of oxygen vacancies around the Ce-ions is the main ingredient to change the Ce oxidation state, and hence the magnetic properties of Ce-doped SnO2 NPs. The presented results pave the way for handling the magnetic properties of oxides through the control of the oxidation state of impurities.

9.
Phys Chem Chem Phys ; 22(6): 3702-3714, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32003381

RESUMO

In this work, we present a coupled experimental and theoretical first-principles investigation on one of the more promising oxide-diluted magnetic semiconductors, the Sn1-xCoxO2 nanoparticle system, in order to see the effect of cobalt doping on the physical and chemical properties. Our findings suggest that progressive surface enrichment with dopant ions plays an essential role in the monotonous quenching of the surface disorder modes. That weakening is associated with the passivation of the oxygen vacancies as the Co excess at the surface becomes larger. Room-temperature 119Sn Mössbauer spectroscopy data analysis revealed the occurrence of a distribution of isomer shifts, related to the different non-equivalent surroundings of Sn4+ ions and the coexistence of Sn2+/Sn4+ at the particle surfaces provoked by the inhomogeneous distribution of Co ions, in agreement with the X-ray photoelectron spectroscopy measurements. Magnetic measurements revealed a paramagnetic behavior of the Co ions dispersed in the rutile-type matrix with antiferromagnetic correlations, which become stronger as the Co content is increased. Theoretical calculations show that a defect with two Co mediated by a nearby oxygen vacancy is the most likely defect. The predicted effects of this defect complex are in accordance with the experimental results.

10.
Rev Gastroenterol Mex (Engl Ed) ; 85(4): 390-398, 2020.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-31740166

RESUMO

INTRODUCTION AND AIMS: Insulin-like growth factor 1 is modulated by the insulin-like growth factor-binding proteins (IGFBPs) that are synthesized in the liver. The aim of the present study was to evaluate the concentrations of IGFBPs 1-7 in patients with chronic hepatitis C and study their association with fibrosis stage. PATIENTS AND METHODS: A prospective, cross-sectional study was conducted that included patients with chronic hepatitis C. The stages of fibrosis were determined through FibroTest and FibroScan and the patients were compared with a control group. Serum levels of IGFBPs 1-7 were quantified through multiple suspension arrays. The Kruskal-Wallis test, Mann-Whitney U test, Spearman's correlation, and ROC curves were used for the statistical analysis. RESULTS: Upon comparing the patients and controls, the highest concentrations were found in IGFBPs 1, 2, 4, and 7 (p=0.02, p=0.002, p=0.008, and p<0.001, respectively). IGFBP-3 levels had a tendency to be lower in the patients (p=0.066), whereas values were similar between patients and controls for IGFBP-5 and 6 (p=0.786 and p=0.244, respectively). Of the seven IGFBPs, IGFBP-3 concentrations were the highest. There were significant differences between fibrosis stages for IGFBP-5 and IGFBP-7. CONCLUSION: IGFBPs play a relevant role in the fibrotic process in liver damage. IGFBP-7, in particular, differentiates fibrosis stages, making it a potential serum biomarker.


Assuntos
Hepatite C Crônica/complicações , Hepatite C Crônica/metabolismo , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/biossíntese , Cirrose Hepática/etiologia , Cirrose Hepática/metabolismo , Adulto , Estudos Transversais , Progressão da Doença , Feminino , Humanos , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade
11.
Clin Oral Investig ; 22(9): 3061-3070, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29476334

RESUMO

OBJECTIVES: The aim of this case-control study was to carry out an oral health assessment on a group of Alzheimer's patients and to establish a hypothesis regarding the implication of the characteristics of the disease and the treatment of oral health. MATERIALS AND METHODS: A total of 70 Alzheimer's patients, residents at the Alzheimer Center Reina Sofia Foundation (Madrid, Spain) and at the Alzheimer State Reference Center (Salamanca, Spain), and 36 controls (companions/acquaintances), were studied by oral examination and saliva sampling. The oral health indices DMFT/DMFS, CPI, the prosthetic condition, oral hygiene, saliva volume, and pH, as well as the specific microbiological parameters governing the risk of developing caries were assessed. RESULTS: Alzheimer's patients exhibited, as compared to the control group, (1) fewer teeth (10.9 ± 10.5 vs 23.7 ± 6.5), (2) fewer obturations (2.2 ± 3.4 vs 6.6 ± 5.6), (3) fewer periodontally healthy sextants (0.1 ± 0.4 vs 1.4 ± 2.2), (4) worse oral hygiene (43.1 vs 72.2% brushed), (5) greater use of removable prostheses (47.8 vs 8.4%), (6) higher incidence of candida infection (11.8 vs 0.0%) and cheilitis (15.9 vs 0.0%), (7) lower salivary flow (0.6 ± 0.6 vs 1.1 ± 0.6), and (8) lower buffering capacity (46 vs 80%). CONCLUSIONS: After taking into account the influence of age, Alzheimer's patients had worse oral health (caries and periodontal disease), more mucosal lesions (cheilitis and candidiasis), and worse saliva quantity and quality. CLINICAL RELEVANCE: Clinicians should be aware of the implications of Alzheimer's disease in oral health, in order to stablish the effective preventive measures and the optimal treatment plan.


Assuntos
Doença de Alzheimer/complicações , Avaliação Geriátrica , Saúde Bucal , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Espanha
12.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-29107751

RESUMO

AIM: To assess the diagnostic accuracy of 18F-FDG PET/contrast enhanced computed tomography (ceCT) in the detection of asymptomatic recurrences in patients with lymphoma. MATERIAL AND METHODS: Patients with lymphoma and clinical complete remission underwent 18F-FDG PET/ceCT for standard follow-up.18F-FDG PET and ceCT were evaluated blindly by two independent observers, and classified as positive or negative for recurrence. Additionally a combined evaluation of both techniques was performed. The final diagnosis was established by histopathological analysis or a clinical follow-up longer than 6 months. Statistical diagnostic parameters and concordance levels between both diagnostic techniques were calculated. RESULTS: A total of 114 explorations on 90 patients were analyzed. Only 4 patients were diagnosed as asymptomatic recurrence during the follow-up. 18F-FDG PET/ceCT, 18F-FDG PET and ceCT showed an association with the final diagnosis (p=0.002 and χ2=11.96; p<0.001 and χ2=15.60; p=0.001 and χ2=11.96, respectively). The concordance between 18F-FDG PET and ceCT was moderate/high and significant (kappa=0.672; p<0.001). A sensitivity and specificity of 50% and 88% was obtained for the 18F-FDG PET/ceCT civ, 50% and 93% for the 18F-FDG PET, and 50% and 91% for the ceCT. CONCLUSION: The combined use of 18F-FDG PET/ceCT did not offer any advantage compared to any isolated diagnostic technique in the detection of asymptomatic lymphoma recurrence.


Assuntos
Linfoma/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Doenças Assintomáticas , Feminino , Radioisótopos de Flúor , Fluordesoxiglucose F18 , Seguimentos , Humanos , Masculino , Compostos Radiofarmacêuticos , Recidiva , Indução de Remissão , Estudos Retrospectivos , Sensibilidade e Especificidade , Método Simples-Cego
13.
Trials ; 18(1): 346, 2017 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-28732521

RESUMO

BACKGROUND: The coracoid approach is recognized as the simplest approach to perform brachial plexus anaesthesia, but needle visualization needs to be improved. With a different needle entry point, the retroclavicular approach confers a perpendicular angle between the ultrasound and the needle, which theoretically enhances needle visualization. This trial compares these two techniques. The leading hypothesis is that the retroclavicular approach is comparable to the infraclavicular coracoid approach in general aspects, but needle visualization is better with this novel approach. METHODS: We designed a multicentre, randomized, non-inferiority trial. Patients eligible for the study are older than 18 years, able to consent, will undergo urgent or elective upper limb surgery distal to the elbow and are classified with American Society of Anaesthesiologists risk score (ASA) I-III. They will be excluded if they meet contraindicated criteria to regional anaesthesia, have affected anatomy of the clavicle or are pregnant. Randomization will be done by a computer-generated randomization schedule stratified for each site and in 1:1 ratio, and concealment will be maintained with opaque, sealed envelopes in a locked office. The primary outcome, the performance time, will be analyzed using non-inferiority analysis while secondary outcomes will be analyzed with superiority analysis. Needle visualization will be ranked on a Likert scale of 1-5 that is subjective and represents a pitfall. Two separate persons will rank needle visualization to compensate this pitfall. According to previous studies, 49 patients per group are required for statistical power of 0.90 and one-sided type I error of 0.05. DISCUSSION: The conduct of this study will bring clear answers to our questions and, if our hypothesis is confirmed, will confer an anatomic alternative to difficult coracoid infraclavicular brachial blocks or could even become a standard for brachial plexus anaesthesia. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02913625 . Registered on 12 September 2016.


Assuntos
Anestésicos Locais/administração & dosagem , Bloqueio do Plexo Braquial/métodos , Plexo Braquial , Extremidade Superior/inervação , Anestésicos Locais/efeitos adversos , Bloqueio do Plexo Braquial/efeitos adversos , Protocolos Clínicos , Feminino , Humanos , Injeções , Masculino , Agulhas , Quebeque , Projetos de Pesquisa , Fatores de Tempo , Resultado do Tratamento , Ultrassonografia de Intervenção , Extremidade Superior/cirurgia
14.
BMC Med Res Methodol ; 17(1): 106, 2017 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-28716047

RESUMO

BACKGROUND: The standard definition for protocol adherence is the proportion of all scheduled doses that are delivered. In clinical research, this definition has several limitations when evaluating protocol adherence in trials that study interventions requiring continuous titration. DISCUSSION: Building upon a specific case study, we analyzed a recent trial of a continuously titrated intervention to assess the impact of different definitions of protocol deviations on the interpretation of protocol adherence. The OVATION pilot trial was an open-label randomized controlled trial of higher (75-80 mmHg) versus lower (60-65 mmHg) mean arterial pressure (MAP) targets for vasopressor therapy in shock. In this trial, potential protocol deviations were defined as MAP values outside the targeted range for >4 consecutive hours during vasopressor therapy without synchronous and consistent adjustments of vasopressor doses. An adjudication committee reviewed each potential deviation to determine if it was clinically-justified or not. There are four reasons for this contextual measurement and reporting of protocol adherence. First, between-arm separation is a robust measure of adherence to complex protocols. Second, adherence assessed by protocol deviations varies in function of the definition of deviations and the frequency of measurements. Third, distinguishing clinically-justified vs. not clinically-justified protocol deviations acknowledges clinically sensible bedside decision-making and offers a clear terminology before the trial begins. Finally, multiple metrics exist to report protocol deviations, which provides different information but complementary information on protocol adherence. CONCLUSIONS: In trials of interventions requiring continuous titration, metrics used for defining protocol deviations have a considerable impact on the interpretation of protocol adherence. Definitions for protocol deviations should be prespecified and correlated with between-arm separation, if it can be measured.


Assuntos
Protocolos Clínicos , Cooperação do Paciente , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Projetos de Pesquisa/normas , Pressão Arterial/efeitos dos fármacos , Humanos , Hipotensão/tratamento farmacológico , Hipotensão/etiologia , Projetos Piloto , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Choque/complicações , Vasoconstritores/uso terapêutico
15.
J Phys Condens Matter ; 27(9): 095301, 2015 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-25679305

RESUMO

In this study, we report on the structural and hyperfine properties of Al-doped SnO2 nanoparticles synthesized by a polymer precursor method. The x-ray diffraction data analysis carried out using the Rietveld refinement method shows the formation of only rutile-type structures in all samples, with decreasing of the mean crystallite size as the Al content. A systematic study of the unit cell, as well as the vicinity of the interstitial position show strong evidence of two doping regimes in the rutile-type structure of SnO2. Below 7.5 mol% doping a dominant substitutional solution of Al(+3) and Sn(4+)-ions is determined. However, the occupation of both substitutional and interstitial sites is determined above 7.5 mol% doping. These findings are in good agreement with theoretical ab initio calculations.

16.
Biochim Biophys Acta ; 1850(2): 343-51, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25445712

RESUMO

BACKGROUND: Plasma levels of pancreatic polypeptide (PP) rise upon food intake. Although other pancreatic islet hormones, such as insulin and glucagon, have been extensively investigated, PP secretion and actions are still poorly understood. METHODS: The release of PP upon glucose stimulation and the effects of PP on glucagon and insulin secretion were analyzed in isolated pancreatic islets. Expression of PP receptor (PPYR1) was investigated by immunoblotting, quantitative RT-PCR on sorted pancreatic islet cells, and immunohistochemistry. RESULTS: In isolated mouse pancreatic islets, glucose stimulation increased PP release, while insulin secretion was up and glucagon release was down. Direct exposure of islets to PP inhibited glucagon release. In mouse islets, PPYR1 protein was observed by immunoblotting and quantitative RT-PCR revealed PPYR1 expression in the FACS-enriched glucagon alpha-cell fraction. Immunohistochemistry on pancreatic sections showed the presence of PPYR1 in alpha-cells of both mouse and human islets, while the receptor was absent in other islet cell types and exocrine pancreas. CONCLUSIONS: Glucose stimulates PP secretion and PP inhibits glucagon release in mouse pancreatic islets. PP receptors are present in alpha-cells of mouse and human pancreatic islets. GENERAL SIGNIFICANCE: These data demonstrate glucose-regulated secretion of PP and its effects on glucagon release through PPYR1 receptors expressed by alpha-cells.


Assuntos
Regulação da Expressão Gênica/fisiologia , Células Secretoras de Glucagon/metabolismo , Glucagon/metabolismo , Polipeptídeo Pancreático/metabolismo , Receptores de Neuropeptídeo Y/biossíntese , Animais , Células Cultivadas , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Células Secretoras de Glucagon/citologia , Glucose/farmacologia , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Edulcorantes/farmacologia
17.
Radiologia ; 56(6): 524-32, 2014.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-23294850

RESUMO

OBJECTIVES: To evaluate the radiologic and pathologic responses to neoadjuvant chemotherapy and their correlation in the molecular subtypes of breast cancer and to analyze their impact in disease-free survival. MATERIAL AND METHODS: We included 205 patients with breast cancer treated with neoadjuvant chemotherapy. We evaluated the radiologic response by comparing MRI images acquired before and after chemotherapy. The pathologic response was classified on the Miller and Payne scale. For each subtype (HER2+, TN, luminal A, luminal B HER2-, and luminal B HER2+), we used the χ(2) test, Student's t-test, ANOVA, and Kendall's Tau-b to evaluate the radiologic response and the pathologic response, the radiologic-pathologic correlation, and the disease-free survival. RESULTS: The subtypes HER2+ (62.1%) and TN (45.2%) had higher rates of complete radiologic response. The pathologic response was 65.5% in the HER2+ subtype, 38.1% in the TN subtype, 2.6% in the luminal A subtype, 8.2% in the luminal B HER2- subtype, and 31% in the luminal B HER2+ subtype. The rate of radiologic-pathologic correlation was significant in all subtypes, higher in TN and HER2 (Tau-b coefficients 0.805 and 0.717, respectively). Disease-free survival was higher in HER2+ (91.9±3.3 months) and lower in TN (69.5±6.3 months), with significant differences between the cases with poor and good radiologic responses (P=.040). Survival was greater in cases with good radiologic response, except in cases with luminal A subtype. CONCLUSION: MRI can be a useful tool that provides information about the evolution of breast cancer treated with neoadjuvant chemotherapy, which varies with the immunohistochemical subtype.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/tratamento farmacológico , Imageamento por Ressonância Magnética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Quimioterapia Adjuvante , Intervalo Livre de Doença , Feminino , Humanos , Pessoa de Meia-Idade , Terapia Neoadjuvante , Estudos Retrospectivos
18.
J Dairy Sci ; 96(5): 2837-46, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23498008

RESUMO

Objectives were to investigate progesterone concentrations and fertility comparing 2 different intervals from PGF(2α) treatment and induced ovulation in an estrogen-based ovulation synchronization protocol for timed artificial insemination (TAI) or timed embryo transfer (TET) in lactating dairy cows. A total of 1,058 lactating Holstein cows [primiparous (n=371) and multiparous (n=687)], yielding 34.1 ± 0.33 kg of milk/d at various days in milk were randomly assigned to receive treatment with PGF(2α) on either d 7 or 8 of the following protocol: d 0: 2mg of estradiol benzoate + controlled internal drug release device; d 8: controlled internal drug release device removal + 1.0mg of estradiol cypionate; d 10: TAI or d 17: TET. Only cows with a corpus luteum at d 17 received an embryo and all cows received GnRH at TET. Pregnancy diagnoses were performed by detection (transrectal ultrasonography) of an embryo on d 28 or a fetus on d 60. Fertility [pregnancy per artificial insemination (P/AI) or pregnancy per embryo transfer (P/ET)] was affected by breeding technique (AI vs. ET) and time of PGF(2α) treatment (d 7 vs. 8) at the 28-d pregnancy diagnosis for TAI [32.9% (238) vs. 20.6% (168)] and TET cows [47% (243) vs. 40.7% (244)] and at the 60-d pregnancy diagnosis for TAI [30% (238) vs. 19.2% (168)] and TET cows [37.9% (243) vs. 33.5% (244)]. The progesterone (P4) concentration at d 10 altered fertility in TAI cows, with higher P/AI in cows with P4 concentration <0.1 ng/mL compared with cows with P4 concentration ≥ 0.1 ng/mL, and in ET cows, with higher P/ET in cows with P4 concentration <0.22 ng/mL compared with cows with P4 concentration ≥ 0.22 ng/mL. Prostaglandin F(2α) treatment at d 7 increased the percentage of cows with P4 <0.1 ng/mL on d 10 [39.4 (85) vs. 23.2 (54)]. Reducing the period between PGF(2α) and TAI from 72 to 48 h in dairy cows resulted in a clear reduction in fertility in cows bred by TAI and a subtle negative effect in cows that received TET. The earlier PGF(2α) treatment benefits are most likely mediated through gamete transport, fertilization, or early embryo development and a more subtle effect of earlier PGF(2α) treatment that may be mediated through changes in the uterine or hormonal environment that manifests itself after ET on d 7.


Assuntos
Dinoprosta/farmacologia , Transferência Embrionária/veterinária , Estrogênios/farmacologia , Inseminação Artificial/veterinária , Animais , Bovinos , Preparações de Ação Retardada , Dinoprosta/administração & dosagem , Esquema de Medicação/veterinária , Transferência Embrionária/métodos , Estrogênios/administração & dosagem , Detecção do Estro , Sincronização do Estro/efeitos dos fármacos , Feminino , Inseminação Artificial/métodos , Lactação , Ovulação/efeitos dos fármacos , Gravidez/efeitos dos fármacos
19.
Anim Reprod Sci ; 127(3-4): 140-7, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21899963

RESUMO

The objective of this study was to evaluate the associations among milk production, rectal temperature, and pregnancy maintenance in lactating recipient dairy cows. Data were collected during an 11-mo period from 463 Holstein cows (203 primiparous and 260 multiparous) assigned to a fixed-time embryo transfer (ET) protocol. Only cows detected with a visible corpus luteum immediately prior to ET were used. Rectal temperatures were collected from all cows on the same day of ET. Milk production at ET was calculated by averaging individual daily milk production during the 7d preceding ET. Pregnancy diagnosis was performed by transrectal ultrasonography 21d after ET. Cows were ranked and assigned to groups according to median milk production (median=35kg/d; HPROD=above median; LPROD=below median) and rectal temperature (≤39.0°C=LTEMP; >39.0°C=HTEMP). A milk production×temperature group interaction was detected (P=0.04) for pregnancy analysis because HTEMP cows ranked as LPROD were 3.1 time more likely to maintain pregnancy compared with HTEMP cows ranked as HPROD (P=0.03). Milk production did not affect (P=0.55) odds of pregnancy maintenance within LTEMP cows, however, and no differences in odds of pregnancy maintenance were detected between HTEMP and LTEMP within milk production groups (P>0.11). Within HTEMP cows, increased milk production decreased the probability of pregnancy maintenance linearly, whereas within LTEMP cows, increased milk production increased the probability of pregnancy maintenance linearly. Within HPROD, increased rectal temperature decreased the probability of pregnancy maintenance linearly, whereas within LPROD cows, no associations between rectal temperatures and probability of cows to maintain pregnancy were detected. In summary, high-producing dairy cows with rectal temperatures below 39.0°C did not experience reduced pregnancy maintenance to ET compared to cohorts with reduced milk production.


Assuntos
Temperatura Corporal/fisiologia , Bovinos , Transferência Embrionária , Lactação/fisiologia , Leite/metabolismo , Manutenção da Gravidez/fisiologia , Animais , Bovinos/metabolismo , Bovinos/fisiologia , Eficiência , Transferência Embrionária/métodos , Transferência Embrionária/veterinária , Feminino , Gravidez , Reto , Fatores de Tempo , Transplante
20.
Theriogenology ; 75(6): 1153-60, 2011 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-21247621

RESUMO

The objective was to compare two protocols for synchronizing ovulation in lactating Holstein cows submitted to timed AI (TAI) or timed ET (TET). Within each farm (n = 8), cows (n = 883; mean ± SEM 166.24 ± 3.27 d postpartum, yielding 36.8 ± 0.34 kg of milk/d) were randomly assigned to receive either: 1) an intravaginal progesterone insert (CIDR®) with 1.9 g of progesterone + GnRH on Day -10, CIDR® withdrawal + PGF2α on Day -3, and 1 mg estradiol cypionate on Day -2 (treatment GP-P-E; n(TAI) = 180; n(TET) = 260); or 2) a CIDR® insert + 2 mg estradiol benzoate on Day -10, PGF2α on Day -3, CIDR® withdrawal + 1 mg estradiol cypionate on Day -2 (treatment EP-P-E; n(TAI) = 174; n(TET) = 269). Cows were subsequently randomly assigned to receive either TAI on Day 0 or TET on Day 7. Serum progesterone concentration on Day -3 was greater in GP-P-E than in EP-P-E (2.89 ± 0.15 vs 2.29 ± 0.15 ng/mL; P < 0.01), with no significant effect of group on serum progesterone on Day 7. Compared to cows submitted to TAI, those submitted to TET had greater pregnancy rates on Day 28 (44.0% [233/529] vs 29.7% [105/354]; P < 0.001) and on Day 60 (37.6% [199/529] vs 26.5 [94/354]; P < 0.001). However, there were no effects of treatments (GP-P-E vs EP-P-E; P > 0.10) on synchronization (87.0% [383/440] vs 85.3% [378/443]), conception (TAI: 35.3% [55/156] vs 33.8% [50/148]; TET: 50.7% [115/227] vs 51.3% [118/230]) and pregnancy rates on Days 28 (TAI: 30.5% [55/180] vs 28.7% [50/174]; TET: 44.2% [115/260] vs 43.9% [118/269]) and 60 (TAI: 27.2% [49/80] vs 25.9% [45/174]; TET: 38.8% [101/260] vs 36.4% [98/269]). In conclusion, GP-P-E increased serum progesterone concentrations on Day -3, but rates of synchronization, conception, and pregnancy were not significantly different between cows submitted to GP-P-E and EP-P-E protocols, regardless of whether they were inseminated or received an embryo.


Assuntos
Bovinos , Transferência Embrionária/veterinária , Estradiol/análogos & derivados , Hormônio Liberador de Gonadotropina/farmacologia , Inseminação Artificial/veterinária , Progesterona/farmacologia , Animais , Transferência Embrionária/métodos , Estradiol/administração & dosagem , Estradiol/farmacologia , Sincronização do Estro , Feminino , Hormônio Liberador de Gonadotropina/administração & dosagem , Inseminação Artificial/métodos , Lactação , Leite/metabolismo , Gravidez , Taxa de Gravidez , Progesterona/administração & dosagem , Progesterona/sangue
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