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1.
Morphologie ; 106(352): 52-55, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33483185

RESUMO

OBJECTIVE: We aim to describe the supraclavicular nerve's vascular entrapment by the external jugular vein as an unreported anatomical finding. CASE DESCRIPTION: In a routine cadaveric dissection, the superficial emergence of the first division of the left supraclavicular nerve emerged along a duct formed through the external jugular vein. No other vascular or neural anatomical abnormalities were found in the surrounding structures. CONCLUSION: This unreported vascular entrapment of the supraclavicular nerve by the external jugular may harbour clinical implications for surgical and endovascular procedures on the external jugular vein and in refractory thoracic and scapular waist pain.


Assuntos
Veias Jugulares , Síndromes de Compressão Nervosa , Dissecação , Humanos , Veias Jugulares/diagnóstico por imagem , Veia Subclávia/diagnóstico por imagem
2.
Mol Cell Neurosci ; 103: 103467, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32004684

RESUMO

During neural development, complex organisms rely on progressive and regressive events whereby axons, synapses, and neurons are overproduced followed by selective elimination of a portion of these components. Tumor necrosis factor α (TNFα) together with its cognate receptor (Tumor necrosis factor receptor 1; TNFR1) have been shown to play both regressive (i.e. forward signaling from the receptor) and progressive (i.e. reverse signaling from the ligand) roles in sympathetic neuron development. In contrast, a paralog of TNFR1, p75 neurotrophic factor receptor (p75NTR) promotes mainly regressive developmental events in sympathetic neurons. Here we examine the interplay between these paralogous receptors in the regulation of axon branch elimination and arborization. We confirm previous reports that these TNFR1 family members are individually capable of promoting ligand-dependent suppression of axon growth and branching. Remarkably, p75NTR and TNFR1 physically interact and p75NTR requires TNFR1 for ligand-dependent axon suppression of axon branching but not vice versa. We also find that p75NTR forward signaling and TNFα reverse signaling are functionally antagonistic. Finally, we find that TNFα reverse signaling is necessary for nerve growth factor (NGF) dependent axon growth. Taken together these findings demonstrate several levels of synergistic and antagonistic interactions using very few signaling pathways and that the balance of these synergizing and opposing signals act to ensure proper axon growth and patterning.


Assuntos
Axônios/metabolismo , Receptores de Fator de Crescimento Neural/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Células Cultivadas , Camundongos Knockout , Neurogênese/fisiologia , Transdução de Sinais/fisiologia
3.
J Assist Reprod Genet ; 37(7): 1567-1577, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32594284

RESUMO

PURPOSE: The state of limited resource settings that Coronavirus (COVID-19) pandemic has created globally should be taken seriously into account especially in healthcare sector. In oncofertility, patients should receive their fertility preservation treatments urgently even in limited resource settings before initiation of anticancer therapy. Therefore, it is very crucial to learn more about oncofertility practice in limited resource settings such as in developing countries that suffer often from shortage of healthcare services provided to young patients with cancer. METHODS: As an extrapolation during the global crisis of COVID-19 pandemic, we surveyed oncofertility centers from 14 developing countries (Egypt, Tunisia, Brazil, Peru, Panama, Mexico, Colombia, Guatemala, Argentina, Chile, Nigeria, South Africa, Saudi Arabia, and India). Survey questionnaire included questions on the availability and degree of utilization of fertility preservation options in case of childhood cancer, breast cancer, and blood cancer. RESULTS: All surveyed centers responded to all questions. Responses and their calculated oncofertility scores showed different domestic standards for oncofertility practice in case of childhood cancer, breast cancer, and blood cancer in the developing countries under limited resource settings. CONCLUSIONS: Medical practice in limited resource settings has become a critical topic especially after the global crisis of COVID-19 pandemic. Understanding the resources necessary to provide oncofertility treatments is important until the current COVID-19 pandemic resolves. Lessons learned will be valuable to future potential worldwide disruptions due to infectious diseases or other global crises.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/prevenção & controle , Atenção à Saúde/normas , Preservação da Fertilidade/métodos , Neoplasias/terapia , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Betacoronavirus/isolamento & purificação , COVID-19 , Infecções por Coronavirus/transmissão , Infecções por Coronavirus/virologia , Atenção à Saúde/economia , Países em Desenvolvimento , Feminino , Preservação da Fertilidade/economia , Preservação da Fertilidade/estatística & dados numéricos , Humanos , Neoplasias/virologia , Pneumonia Viral/transmissão , Pneumonia Viral/virologia , SARS-CoV-2 , Inquéritos e Questionários
4.
Mediators Inflamm ; 2013: 967067, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23533314

RESUMO

Interleukin-(IL-) 12 has been recently suggested to participate during development of insulin resistance in obese mice. Nevertheless, serum IL-12 levels have not been accurately determined in overweight and obese humans. We thus studied serum concentrations of IL-12 in Mexican adult individuals, examining their relationship with low-grade inflammation and obesity-related parameters. A total of 147 healthy individuals, 43 normal weight, 61 overweight, and 43 obese subjects participated in the study. Circulating levels of IL-12, tumor necrosis factor-alpha (TNF- α ), leptin, insulin, glucose, total cholesterol, and triglyceride were measured after overnight fasting in all of the study subjects. Waist circumference and body fat percentage were recorded for all the participants. Serum IL-12 was significantly higher in overweight and obese individuals than in normal weight controls. Besides being strongly related with body mass index (r = 0.5154), serum IL-12 exhibited a significant relationship with abdominal obesity (r = 0.4481), body fat percentage (r = 0.5625), serum glucose (r = 0.3158), triglyceride (r = 0.3714), and TNF- α (r = 0.4717). Thus, serum levels of IL-12 are increased in overweight and obese individuals and show a strong relationship with markers of low-grade inflammation and obesity in the Mexican adult population. Further research is needed to understand the role of IL-12 in developing obesity-associated alterations in humans.


Assuntos
Inflamação/sangue , Interleucina-12/sangue , Obesidade/sangue , Adulto , Feminino , Humanos , Insulina/sangue , Leptina/sangue , Masculino , Triglicerídeos/sangue , Fator de Necrose Tumoral alfa/sangue , Adulto Jovem
5.
Braz J Biol ; 83: e272853, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37672435

RESUMO

The aim of this study was to determine the acute toxicity of the essential oils (EOs) of Aloysia triphylla, Lippia gracilis and Piper aduncum in juvenile tambaqui (Colossoma macropomum), and evaluate the possible histopathological alterations in their gills. For the acute toxicity tests, juvenile tambaqui (n=24/treatment) were distributed in six treatments with three replicates, which comprised the control and five EO concentrations of A. triphylla (60, 80, 100, 120 and 140 mg L-1), L. gracilis (35, 40, 45, 50 and 55 mg L-1) and P. aduncum (42.5, 45, 47.5, 50 and 52.5 mg L-1), with an exposure period of 4 h. The mortality rate and severity of damage to the tambaqui gills were proportional to the increase in the concentration of the EO, with LC50-4 h values estimated at 109.57 mg L -1 for A. triphylla, 41.63 mg L -1 for L. gracilis and 48.17 mg L -1 for P. aduncum. The main morphological damages observed in the gills of the tambaqui exposed to the three EOs, were Grade I: hypertrophy and hyperplasia of lamellar epithelial cells, lamellar fusion, epithelial detachment, capillary dilation and constriction, proliferation of chloride cells and mucosal cells and edema; in low frequency Grade II damage as epithelial rupture and lamellar aneurysm. Necrosis (Grade III damage) was observed only in gill lamellae exposed to P. aduncum EO (47.5, 50.0 and 52.5 mg L-1). Concentrations of EOs below LC50-4 h can be used sparingly, for short periods of exposure for the treatment of diseases in tambaqui breeding.


Assuntos
Caraciformes , Lippia , Óleos Voláteis , Verbenaceae , Animais , Óleos Voláteis/toxicidade , Melhoramento Vegetal
6.
Rev Peru Med Exp Salud Publica ; 40(2): 132-140, 2023.
Artigo em Espanhol, Inglês | MEDLINE | ID: mdl-38232259

RESUMO

OBJECTIVES.: Motivation for the study. During the COVID-19 pandemic, the mortality rate from this disease was higher in adults and the elderly. Therefore, it is important to identify the factors that were associated with mortality from COVID-19 in adults, by age group. Main findings. Chronic neurological disease, kidney disease, liver disease, and cancer increased the risk of dying from COVID-19 in the three age groups we analyzed, which were made up of hospitalized patients from Lima and Callao. The risk of mortality associated with comorbidities was higher in patients aged 18 to 29. Implications. This study helps to identify the groups of patients with the highest risk of death from COVID-19, according to age group and type of comorbidity. . To evaluate comorbidities associated with mortality in adult patients hospitalized due to COVID-19 in hospitals in Lima and Callao. MATERIALS AND METHODS.: In this retrospective cohort study, we analyzed data from adult patients hospitalized due to COVID-19 reported to the National Epidemiological Surveillance System of the Peruvian Ministry of Health from March to October 2020. We estimated relative risks with 95% confidence intervals using Poisson regression models with robust variance to assess comorbidities associated with mortality by age group: young adults (18-29 years), adults (30-59 years) and older adults (≥60 years). RESULTS.: We included 2366 young adults, 23,781 adults and 25,356 older adults. Older adults had the highest mortality (63.7%) compared to adults (27.1%) and young adults (8.5%). Regardless of age group, the presence of neurological disease, renal disease, liver disease, and cancer was associated with an increased risk of mortality. Additionally, cardiovascular disease was also a risk factor in young adults; obesity, diabetes, cardiovascular disease, chronic lung disease, and immunodeficiency in adults; and obesity and chronic lung disease in the elderly. CONCLUSIONS.: Regardless of age groups, individuals with chronic neurologic disease, renal disease, liver disease, and cancer were at high risk of death from COVID-19.


OBJETIVOS.: Motivation for the study. During the COVID-19 pandemic, the mortality rate from this disease was higher in adults and the elderly. Therefore, it is important to identify the factors that were associated with mortality from COVID-19 in adults, by age group. Main findings. Chronic neurological disease, kidney disease, liver disease, and cancer increased the risk of dying from COVID-19 in the three age groups we analyzed, which were made up of hospitalized patients from Lima and Callao. The risk of mortality associated with comorbidities was higher in patients aged 18 to 29. Implications. This study helps to identify the groups of patients with the highest risk of death from COVID-19, according to age group and type of comorbidity. . Evaluar las comorbilidades asociadas a la mortalidad en pacientes adultos hospitalizados por COVID-19 de diferentes grupos de edad en hospitales de Lima y Callao. MATERIALES Y MÉTODOS.: En este estudio de cohorte retrospectiva analizamos datos de pacientes adultos hospitalizados por COVID-19, notificados al Sistema Nacional de Vigilancia Epidemiológica del Ministerio de Salud de Perú de marzo a octubre del 2020. Se estimaron riesgos relativos con intervalos de confianza al 95% mediante modelos de regresión de Poisson con varianza robusta para evaluar las comorbilidades asociadas a la mortalidad por grupos de edad: jóvenes (18-29 años), adultos (30-59 años) y mayores (≥60 años). RESULTADOS.: Se incluyeron 2366 jóvenes, 23781 adultos y 25356 adultos mayores en el análisis. Los adultos mayores presentaron la mortalidad más alta (63,7%) en comparación con adultos (27,1%) y jóvenes (8,5%). Independientemente del grupo de edad, la presencia de enfermedad neurológica, enfermedad renal, enfermedad hepática y cáncer se asoció a un mayor riesgo de mortalidad. Adicionalmente, la enfermedad cardiovascular fue también un factor de riesgo en los jóvenes; la obesidad, la diabetes, la enfermedad cardiovascular, la enfermedad pulmonar crónica y la inmunodeficiencia en los adultos; y la obesidad y la enfermedad pulmonar crónica en los mayores. CONCLUSIONES: Independientemente de los grupos de edad, los individuos con enfermedad neurológica crónica, enfermedad renal, enfermedad hepática y cáncer tendrían un alto riesgo de morir por la COVID-19.


Assuntos
COVID-19 , Doenças Cardiovasculares , Hepatopatias , Neoplasias , Idoso , Adulto Jovem , Humanos , Criança , COVID-19/epidemiologia , Peru/epidemiologia , Pandemias , Estudos Retrospectivos , SARS-CoV-2 , Comorbidade , Fatores de Risco , Obesidade/epidemiologia , Doença Crônica , Hepatopatias/epidemiologia , Hospitalização
7.
bioRxiv ; 2023 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-36712026

RESUMO

Alzheimer's disease (AD) is the most common cause of dementia among older adults. APOE3 Christchurch (R136S, APOE3Ch ) variant homozygosity was reported in an individual with extreme resistance to autosomal dominant AD due to the PSEN1 E280A mutation. This subject had a delayed clinical age at onset and resistance to tauopathy and neurodegeneration despite extremely high amyloid plaque burden. We established induced pluripotent stem (iPS) cell-derived cerebral organoids from this resistant case and from a non-protected kindred control (with PSEN1 E280A and APOE3/3 ). We used CRISPR/Cas9 gene editing to successfully remove the APOE3Ch to wild type in iPS cells from the protected case and to introduce the APOE3Ch as homozygote in iPS cells from the non-protected case to examine causality. We found significant reduction of tau phosphorylation (pTau 202/205 and pTau396) in cerebral organoids with the APOE3Ch variant, consistent with the strikingly reduced tau pathology found in the resistant case. We identified Cadherin and Wnt pathways as signaling mechanisms regulated by the APOE3Ch variant through single cell RNA sequencing in cerebral organoids. We also identified elevated ß-catenin protein, a regulator of tau phosphorylation, as a candidate mediator of APOE3Ch resistance to tauopathy. Our findings show that APOE3Ch is necessary and sufficient to confer resistance to tauopathy in an experimental ex-vivo model establishing a foundation for the development of novel, protected case-inspired therapeutics for tauopathies, including Alzheimer's.

8.
Int J Tuberc Lung Dis ; 27(8): 584-598, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37491754

RESUMO

BACKGROUND: These clinical standards aim to provide guidance for diagnosis, treatment, and management of drug-susceptible TB in children and adolescents.METHODS: Fifty-two global experts in paediatric TB participated in a Delphi consensus process. After eight rounds of revisions, 51/52 (98%) participants endorsed the final document.RESULTS: Eight standards were identified: Standard 1, Age and developmental stage are critical considerations in the assessment and management of TB; Standard 2, Children and adolescents with symptoms and signs of TB disease should undergo prompt evaluation, and diagnosis and treatment initiation should not depend on microbiological confirmation; Standard 3, Treatment initiation is particularly urgent in children and adolescents with presumptive TB meningitis and disseminated (miliary) TB; Standard 4, Children and adolescents should be treated with an appropriate weight-based regimen; Standard 5, Treating TB infection (TBI) is important to prevent disease; Standard 6, Children and adolescents should receive home-based/community-based treatment support whenever possible; Standard 7, Children, adolescents, and their families should be provided age-appropriate support to optimise engagement in care and clinical outcomes; and Standard 8, Case reporting and contact tracing should be conducted for each child and adolescent.CONCLUSION: These consensus-based clinical standards, which should be adapted to local contexts, will improve the care of children and adolescents affected by TB.


Assuntos
Tuberculose Meníngea , Adolescente , Criança , Humanos , Tuberculose Meníngea/tratamento farmacológico , Padrão de Cuidado , Técnica Delphi , Guias de Prática Clínica como Assunto
9.
Int J Tuberc Lung Dis ; 27(9): 658-667, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37608484

RESUMO

BACKGROUND: The aim of these clinical standards is to aid the diagnosis and management of asthma in low-resource settings in low- and middle-income countries (LMICs).METHODS: A panel of 52 experts in the field of asthma in LMICs participated in a two-stage Delphi process to establish and reach a consensus on the clinical standards.RESULTS: Eighteen clinical standards were defined: Standard 1, Every individual with symptoms and signs compatible with asthma should undergo a clinical assessment; Standard 2, In individuals (>6 years) with a clinical assessment supportive of a diagnosis of asthma, a hand-held spirometry measurement should be used to confirm variable expiratory airflow limitation by demonstrating an acute response to a bronchodilator; Standard 3, Pre- and post-bronchodilator spirometry should be performed in individuals (>6 years) to support diagnosis before treatment is commenced if there is diagnostic uncertainty; Standard 4, Individuals with an acute exacerbation of asthma and clinical signs of hypoxaemia or increased work of breathing should be given supplementary oxygen to maintain saturation at 94-98%; Standard 5, Inhaled short-acting beta-2 agonists (SABAs) should be used as an emergency reliever in individuals with asthma via an appropriate spacer device for metered-dose inhalers; Standard 6, Short-course oral corticosteroids should be administered in appropriate doses to individuals having moderate to severe acute asthma exacerbations (minimum 3-5 days); Standard 7, Individuals having a severe asthma exacerbation should receive emergency care, including oxygen therapy, systemic corticosteroids, inhaled bronchodilators (e.g., salbutamol with or without ipratropium bromide) and a single dose of intravenous magnesium sulphate should be considered; Standard 8, All individuals with asthma should receive education about asthma and a personalised action plan; Standard 9, Inhaled medications (excluding dry-powder devices) should be administered via an appropriate spacer device in both adults and children. Children aged 0-3 years will require the spacer to be coupled to a face mask; Standard 10, Children aged <5 years with asthma should receive a SABA as-needed at step 1 and an inhaled corticosteroid (ICS) to cover periods of wheezing due to respiratory viral infections, and SABA as-needed and daily ICS from step 2 upwards; Standard 11, Children aged 6-11 years with asthma should receive an ICS taken whenever an inhaled SABA is used; Standard 12, All adolescents aged 12-18 years and adults with asthma should receive a combination inhaler (ICS and rapid onset of action long-acting beta-agonist [LABA] such as budesonide-formoterol), where available, to be used either as-needed (for mild asthma) or as both maintenance and reliever therapy, for moderate to severe asthma; Standard 13, Inhaled SABA alone for the management of patients aged >12 years is not recommended as it is associated with increased risk of morbidity and mortality. It should only be used where there is no access to ICS.The following standards (14-18) are for settings where there is no access to inhaled medicines. Standard 14, Patients without access to corticosteroids should be provided with a single short course of emergency oral prednisolone; Standard 15, Oral SABA for symptomatic relief should be used only if no inhaled SABA is available. Adjust to the individual's lowest beneficial dose to minimise adverse effects; Standard 16, Oral leukotriene receptor antagonists (LTRA) can be used as a preventive medication and is preferable to the use of long-term oral systemic corticosteroids; Standard 17, In exceptional circumstances, when there is a high risk of mortality from exacerbations, low-dose oral prednisolone daily or on alternate days may be considered on a case-by-case basis; Standard 18. Oral theophylline should be restricted for use in situations where it is the only bronchodilator treatment option available.CONCLUSION: These first consensus-based clinical standards for asthma management in LMICs are intended to help clinicians provide the most effective care for people in resource-limited settings.


Assuntos
Asma , Países em Desenvolvimento , Adolescente , Adulto , Criança , Humanos , Broncodilatadores/uso terapêutico , Asma/diagnóstico , Asma/tratamento farmacológico , Albuterol , Prednisolona
13.
Rev Esp Anestesiol Reanim (Engl Ed) ; 69(10): 663-673, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36241514

RESUMO

INTRODUCTION: Rapid sequence intubation is an airway rescue and protection technique in which different sedatives are used to perform orotracheal intubation. Etomidate, due to its pharmacokinetic and pharmacodynamic qualities, particularly hemodynamic stability, is the most widely used sedative in this scenario. However, its superiority over other sedatives is controversial. MATERIALS AND METHODS: We performed a meta-analysis using a pre-designed protocol and PRISMA guidelines to evaluate the mean difference between systolic blood pressure before and after administration of the sedative. We also analyzed the relative risks of hypotension. RESULTS: Ten studies were included. The incidence of hypotension in patients receiving etomidate ranged from 6.4% to 75.2%, and between 24.0% and 65.9% in patients receiving other sedatives. No significant differences were found in the mean difference in systolic blood pressure during pre-intubation 0.01 mm Hg (95% CI: -0.90; 0.92) or in post-intubation 0.98 mmHg (95% CI: -0.24; 2.20). The relative risk analysis showed that the risk of hypotension is equal to an RR of 1.19 (95% CI: 0.92-1.54) between those who received etomidate and those who received the other sedatives. CONCLUSIONS: The risk of hypotension after rapid intubation sequence with etomidate does not differ significantly compared to other sedatives. However, the studies included in this review were heterogeneous.


Assuntos
Etomidato , Hipotensão , Humanos , Etomidato/efeitos adversos , Hipnóticos e Sedativos/efeitos adversos , Indução e Intubação de Sequência Rápida , Intubação Intratraqueal/métodos , Hipotensão/induzido quimicamente
16.
Transpl Infect Dis ; 12(1): 69-72, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19708892

RESUMO

Isospora belli is a protozoan that only affects humans, after ingestion of Isospora's oocysts. Immunocompetent patients usually do not develop the infection. Immunocompromised hosts may have profuse diarrhea with other gastrointestinal symptoms. Treatment is based on trimethoprim-sulfamethoxazole. In 2006 we performed an isolated intestinal transplantation in a patient with ultra-short bowel syndrome. Neither rejection nor clinical problems occurred after transplant, but signs of intestinal inflammation were seen in every protocol biopsy starting at the first month post transplant. Almost 3 months after the procedure, the patient was re-admitted with diarrhea. I. belli infection was diagnosed by detection of the oocysts in stool samples. Antibiotic treatment with trimethoprim-sulfamethoxazole was initiated with excellent outcome and without relapses. To the best of our knowledge, this is the first case of isosporosis in a small bowel recipient.


Assuntos
Intestino Delgado/transplante , Isospora/isolamento & purificação , Isosporíase/parasitologia , Adulto , Animais , Fezes/parasitologia , Humanos , Isospora/classificação , Isosporíase/diagnóstico , Masculino , Adulto Jovem
18.
AJNR Am J Neuroradiol ; 40(3): 510-516, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30733253

RESUMO

BACKGROUND AND PURPOSE: Aneurysm hemodynamics has been associated with wall histology and inflammation. We investigated associations between local hemodynamics and focal wall changes visible intraoperatively. MATERIALS AND METHODS: Computational fluid dynamics models were constructed from 3D images of 65 aneurysms treated surgically. Aneurysm regions with different visual appearances were identified in intraoperative videos: 1) "atherosclerotic" (yellow), 2) "hyperplastic" (white), 3) "thin" (red), 4) rupture site, and 5) "normal" (similar to parent artery), They were marked on 3D reconstructions. Regional hemodynamics was characterized by the following: wall shear stress, oscillatory shear index, relative residence time, wall shear stress gradient and divergence, gradient oscillatory number, and dynamic pressure; these were compared using the Mann-Whitney test. RESULTS: Hyperplastic regions had lower average wall shear stress (P = .005) and pressure (P = .009) than normal regions. Flow conditions in atherosclerotic and hyperplastic regions were similar but had higher average relative residence time (P = .03) and oscillatory shear index (P = .04) than thin regions. Hyperplastic regions also had a higher average gradient oscillatory number (P = .002) than thin regions. Thin regions had lower average relative residence time (P < .001), oscillatory shear index (P = .006), and gradient oscillatory number (P < .001) than normal regions, and higher average wall shear stress (P = .006) and pressure (P = .009) than hyperplastic regions. Thin regions tended to be aligned with the flow stream, while atherosclerotic and hyperplastic regions tended to be aligned with recirculation zones. CONCLUSIONS: Local hemodynamics is associated with visible focal wall changes. Slow swirling flow with low and oscillatory wall shear stress was associated with atherosclerotic and hyperplastic changes. High flow conditions prevalent in regions near the flow impingement site characterized by higher and less oscillatory wall shear stress were associated with local "thinning" of the wall.


Assuntos
Hemodinâmica/fisiologia , Aneurisma Intracraniano/patologia , Modelos Cardiovasculares , Humanos , Hidrodinâmica , Imageamento Tridimensional , Aneurisma Intracraniano/fisiopatologia , Fatores de Risco , Estresse Mecânico
19.
J Phys Chem A ; 112(9): 1907-13, 2008 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-18266347

RESUMO

Au+(CO)n complexes are produced in the gas phase via pulsed laser vaporization, expanded in a supersonic jet, and detected with a reflectron time-of-flight mass spectrometer. Complexes up to n = 12 are observed, with mass channels corresponding to the n = 2 and n = 4 showing enhanced intensity. To investigate coordination and structure, individual complexes are mass-selected and probed with infrared photodissociation spectroscopy. Spectra in the carbonyl stretching region are measured for the n = 3-7 species, but no photodissociation is observed for n = 1, 2 due to the strong metal cation-ligand binding. The carbonyl stretch in these systems is blue-shifted 50-100 cm-1 with respect to the free CO vibration (2143 cm-1), providing evidence that these species are so-called "nonclassical" metal carbonyls. Theory at the MP2 and CCSD(T) levels provides structures for these complexes and predicted spectra to compare to the experiment. Excellent agreement is obtained between experiment and theory, establishing that the n = 3 complex is trigonal planar and the n = 4 complex is tetrahedral.

20.
Appl Radiat Isot ; 141: 193-198, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29555376

RESUMO

International dosimetry protocols are based on determinations of absorbed dose to water. Ideally, the phantom material should be water equivalent; that is, it should have the same absorption and scatter properties as water. This study presents theoretical, experimental and Monte Carlo modeling of water-equivalence of Fricke and polymer (NIPAM, PAGAT and itaconic acid ITABIS) gel dosimeters. Mass and electronic densities along with effective atomic number were calculated by means of theoretical approaches. Samples were scanned by standard computed tomography. Photon mass attenuation coefficients and electron stopping powers were examined. Theoretical, Monte Carlo and experimental results confirmed good water-equivalence for all gel dosimeters. Overall variations with respect to water in the low energy radiology range (up to 130 kVp) were found to be less than 3% in average.


Assuntos
Dosímetros de Radiação/normas , Compostos Ferrosos , Géis , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Polímeros , Garantia da Qualidade dos Cuidados de Saúde , Dosímetros de Radiação/estatística & dados numéricos , Radiometria/normas , Radiometria/estatística & dados numéricos , Soluções , Tomografia Computadorizada por Raios X , Água
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