55 results on '"Correia MR"'
Search Results
2. Drug dosing in neonates
- Author
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Correia, MR, primary
- Published
- 2020
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3. Growth of Sb2Se3 thin films by selenization of RF sputtered binary precursors
- Author
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Shongalova, A, Correia, MR, Teixeira, JP, Leitao, JP, Gonzalez, JC, Ranjbar, S, Garud, S, VERMANG, Bart, Cunha, JMV, Salome, PMP, and Fernandes, PA
- Subjects
Sb2Se3 ,XRD ,Thin film ,Raman - Abstract
In this work we present a method to grow Sb2Se3 thin films with a potential use as absorber layers in solar cell structures. The films were grown on several substrates: soda-lime glass, Mo coated soda-lime glass and Si . The Sb-Se precursor’s films were deposited by RF magnetron sputtering and then selenized under a H2Se gas flow. Different selenization temperatures were tested and analysed. Compositional and morphological analyses were performed by Energy Dispersive Spectroscopy and Scanning Electron Microscopy, respectively. Phase identification and structural characterization were done by X-ray Diffraction and Raman scattering spectroscopy showing that Sb2Se3 is the dominant phase with an orthorhombic crystalline structure. Traces of rhombohedral and amorphous Se secondary phases were also observed supported by their Se-rich compositions. Visible-NIR reflectance measurements allowed to extract a direct bandgap with a value close to 1.06 eV. Photoluminescence spectroscopy shows an emission with a broad band at 0.85 eV for samples selenized at lower temperatures and an intense peak at 0.75 eV for the sample selenized at higher temperatures. Electrical characterization shows low free hole concentrations and mobilities. At low temperatures, the nearest neighbour hopping is the dominant mechanism for the electronic transport for the analysed samples. Both electrical and optical properties are influenced by the type of defects present on samples. A discussion is made on the properties that need to be improved in order that these films can be integrated into thin film solar cells. published
- Published
- 2018
4. Multifunctional Materials: A Case Study of the Effects of Metal Doping on ZnO Tetrapods with Bismuth and Tin Oxides
- Author
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Postica, V, Gröttrup, J, Adelung, R, Lupan, O, Mishra, AK, de Leeuw, NH, Ababii, N, Carreira, JFC, Rodrigues, J, Sedrine, NB, Correia, MR, Monteiro, T, Sontea, V, and Mishra, YK
- Subjects
QD - Abstract
Hybrid metal oxide nano- and microstructures exhibit novel properties, which make them promising candidates for a wide range of applications, including gas sensing. In this work, the characteristics of the hybrid ZnO-Bi2O3 and ZnO-Zn2SnO4 tetrapod (T) networks are investigated in detail. The gas sensing studies reveal improved performance of the hybrid networks compared to pure ZnO-T networks. For the ZnO-T-Bi2O3 networks, an enhancement in H2 gas response is obtained, although the observed p-type sensing behavior is attributed to the formed junctions between the arms of ZnO-T covered with Bi2O3 and the modulation of the regions where holes accumulate under exposure to H2 gas. In ZnO-T-Zn2SnO4 networks, a change in selectivity to CO gas with high response is noted. The devices based on individual ZnO-T-Bi2O3 and ZnO-T-Zn2SnO4 structures showed an enhanced H2 gas response, which is explained on the basis of interactions (electronic sensitization) between the ZnO-T arm and Bi2O3 shell layer and single Schottky contact structure, respectively. Density functional theory-based calculations provide mechanistic insights into the interaction of H2 and CO gas molecules with Bi- and Sn-doped ZnO(0001) surfaces, revealing changes in the Fermi energies, as well as charge transfer between the molecules and surface species, which facilitate gas sensing.
- Published
- 2017
5. Celiac disease in Portuguese children and adults with Down syndrome.
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Cerqueira RM, Rocha CM, Fernandes CD, Correia MR, Cerqueira, Rute M, Rocha, Cristina M, Fernandes, Carolina D, and Correia, Manuel R
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- 2010
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6. Analysis of strain depth variations in an In(0.19)Ga(0.81)N layer by Raman spectroscopy
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Correia, MR, Pereira, S., Pereira, E., Frandon, J., Renucci, Ma, Eduardo Alves, Sequeira, Ad, Franco, N., Hoffmann, A., and Rizzi, A.
7. Degradation of structural and optical properties of InGaN/GaN multiple quantum wells with increasing number of wells
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Pereira, S., Correia, MR, Pereira, E., O Donnell, Kp, Eduardo Alves, Barradas, Np, Sequeira, Ad, Franco, N., Watson, Im, Liu, C., Hoffmann, A., and Rizzi, A.
8. Structural and optical characterization of light emitting InGaN/GaN epitaxial layers
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Pereira, S., Correia, MR, Eduardo Alves, and Vilarinho, Pm
9. Correction: Bismuth-Based Therapy: The New Therapy for Obese Patients Undergoing Gastric Bypass Surgery?
- Author
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Cerqueira RM, Correia MR, Pita I, Vilar H, Sousa M, Veloso R, and Manso MC
- Published
- 2024
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10. Pushing Backwards: Evaluating Effectiveness of Conservative Treatment of Intestinal Intussusception.
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Carvalho C, Correia MR, Barros A, Rocha R, Banquart-Leitão J, Carvalho F, and Marinho AS
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- Child, Male, Humans, Infant, Child, Preschool, Female, Retrospective Studies, Treatment Outcome, Conservative Treatment, Treatment Failure, Enema methods, Intussusception diagnosis
- Abstract
Objective: Intestinal intussusception (II) is a common cause for acute abdomen in children, occurring in 0.33 to 0.71 per 1000 children per year. Early diagnosis and treatment are fundamental for prevention of irreversible intestinal damage. The first line of treatment is conservative, with saline reduction enema or air reduction enema. Our goal is to evaluate results with conservative treatment of II in children., Methods: A retrospective single-center review of all patients with diagnosis of II from January 2014 to December 2019 was performed. Demographics, clinical data, treatment option, and results were assessed., Results: Thirty-eight cases were identified. The mean age was 26 months, and 68% were males. Most presented with abdominal pain (95%) and vomiting (66%), after an average of 30 hours. Rectal bleeding was present in 32% of patients. Abdominal ultrasound was performed in all patients for diagnosis. Conservative treatment was first option in 95% of patients, with a global effectiveness of 83% after 1 attempt. Saline reduction enema was more effective than air reduction enema (88% vs 70%), and patients with successful reduction were younger (24 vs 33 months), but neither reached statistical significance. Two patients had a subsequent II episode within 1 week after hospital discharge. Neither age, sex, symptoms and respective duration, rotavirus inoculation, intussuscepted bowel length, nor technique used was predictive of treatment failure or II relapse., Conclusions: Conservative treatment in II is a safe and effective option, preventing invasive surgical procedures. Effectiveness of such treatments may be as high as 88% after 1 attempt, with rapid diet reintroduction. Same-day discharge after oral feeding toleration is safe., Competing Interests: Disclosure: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)
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- 2024
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11. Drug-Related Adverse Reactions in Pediatric Inflammatory Bowel Disease.
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Losa A, Gomes R, Mourão FR, Cardoso SS, Vieira PM, Correia MR, Silva HM, Silva G, Tavares M, Silva ES, and Lima R
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- Humans, Male, Child, Adolescent, Female, Retrospective Studies, Azathioprine adverse effects, Inflammatory Bowel Diseases drug therapy, Colitis, Ulcerative drug therapy, Crohn Disease drug therapy, Drug-Related Side Effects and Adverse Reactions epidemiology
- Abstract
The therapeutic approach to inflammatory bowel disease (IBD) is complex, often involving multiple pharmacologic classes. We aimed to evaluate the prevalence of drug-related adverse reactions (ARs) associated with therapies used in pediatric IBD. We conducted a retrospective study of pediatric patients with IBD followed in a tertiary hospital from 2010 to 2022. Ninety-nine patients were included (62.6% were male), with a median age at diagnosis of 13 years (interquartile range [IQR] 11-15 years). The majority had Crohn's disease (69.7%), followed by ulcerative colitis (21.2%) and unclassified IBD (9.1%). The most prescribed therapies were: immunomodulators (n = 75, 75.8%), exclusive enteral nutrition (n = 61, 61.6%), and biologics (n = 58, 58.6%). During a median follow-up time of 31 months (IQR 11-51 months), the incidence of ARs was 16.2% (16 ARs occurred in 14 patients). The main drug involved was azathioprine (12/16) and the most frequent AR was hepatitis (5/16). Drug discontinuation was necessary in all but 1 case. Of the ARs recorded, 75% were mild to moderate and 81.3% did not require specific treatment; all patients had clinical and/or analytical normalization. There was a positive association between the cumulative number of prescribed drugs and the occurrence of ARs (P = .044). The incidence of ARs was similar to the rates reported in the few existing previous studies. The majority of ARs were mild, but implied the discontinuation of therapy or dose reduction, with a possible impact on disease control., (© 2023, The American College of Clinical Pharmacology.)
- Published
- 2024
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12. Quality of life after otoplasty for prominent ears in children.
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Carvalho C, Marinho AS, Barbosa-Sequeira J, Correia MR, Banquart-Leitão J, and Carvalho F
- Abstract
Aim: Prominent ears are a common congenital malformation and are associated with low self-esteem, social isolation and diminished school performance. Our goal was to evaluate the influence of otoplasty on children's quality of life (QoL)., Material and Methods: Patients submitted to otoplasty from 2016 to 2018 were summoned for a reevaluation. Seventy patients and respective caregivers agreed to participate. Surgical, demographic and clinical data were reviewed from electronic registries., Two Sets of Inquiries Were Performed: Pediatric Quality of Life Inventory 4.0 (for parent and child) and an adaptation of the Glasgow Children Benefit Inventory (GCBI-b). Fifteen patients were excluded for incomplete inquiries., Results: Fifty-five patients were included, 70.9% were males. Median age at surgery was 7.7 ± 3.3 years. Aesthetic dissatisfaction was the main previous negative experience. Median self-report quality of life was 85.6% and parent-report was 86.9%. Median GCBI-b was +20.5, indicating an improvement in patients' QoL. Bullying and high parental expectations for life change post-surgery were predictive of higher GCBI-b scores (p < 0.05). Ninety-six percent of parents would recommend surgery to other children., Conclusions: Otoplasty is a valid treatment option for prominent ears in children,improving not only aesthetics but also health-related QoL., (Copyright © 2022. Published by Elsevier España, S.L.U.)
- Published
- 2023
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13. Management of infantile hemangiomas-experience of a tertiary hospital.
- Author
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Gomes R, Salazar L, Fraga C, Correia MR, Barbosa-Sequeira J, Fernandes A, Álvares S, Banquart Leitão J, and Paiva Coelho M
- Subjects
- Humans, Female, Child, Infant, Male, Propranolol therapeutic use, Retrospective Studies, Tertiary Care Centers, Treatment Outcome, Administration, Oral, Adrenergic beta-Antagonists therapeutic use, Hemangioma diagnosis, Hemangioma drug therapy, Skin Neoplasms diagnosis, Skin Neoplasms drug therapy
- Abstract
The purpose of the study is to describe the experience of a multidisciplinary team in a tertiary hospital regarding the management of Infantile Hemangiomas (IH). The method employed is a retrospective analysis of patients with IH followed in a tertiary pediatric hospital between January 2010 and May 2022. A total of 393 IH were diagnosed (56.7% female), with a median age of 5 months (interquartile range (IQR), 3-10). Imaging investigation was necessary for diagnosis and for exclusion of other IH in 9.2% and 14.3%, respectively. Focal (74.0%) and superficial (59.7%) lesions were more frequent as was facial location (35.9%). Pre-treatment ulceration or hemorrhage occurred in 6.6%. At follow-up, 87.4% regressed partially and 12.6% completely; 2.7% relapsed. Propranolol was started in 30.0% of cases for a median period of 9 months (IQR, 6-12), mainly due to esthetic concerns (41.9%). Side effects occurred in 8.3% (sleep disturbance in 5.1%). Only 1.7% were refractory and 5.9% had a rebound effect. Eleven patients were treated with topical timolol and 41 underwent surgery. Patients that were treated with propranolol had more risk factors (p = 0.016) and presented deeper lesions (p < 0.001) with a larger diameter (p < 0.001); total IH regression was less frequent (p < 0.001). Since 2020, twice-daily dosage was more frequently prescribed than three times daily (p = 0.007) and inpatient initiation of propranolol decreased (p = 0.750), without significant difference in the incidence of adverse reactions, duration of treatment, and lesion evolution. Conclusions: Our protocol proved to be safe and feasible in an outpatient setting and twice daily administration of propranolol was effective. The majority of IH showed at least partial regression. Early detection of high-risk IH is paramount and a multidisciplinary assessment by a specialized team is essential for adequate management. What is Known: • IH are the most common vascular tumors in childhood. Although the majority evolves favorably, treatment may be warranted in selected cases. • Early detection of high-risk IH is paramount, and a multidisciplinary assessment by a specialized team is essential for adequate management. What is New: • One-third of our sample was treated with propranolol. These patients had more risk factors and presented deeper lesions with a larger diameter, and tumor total regression was less frequent. • Our results reinforce safety and feasibility of propranolol initiation in an outpatient setting, including twice daily dosage., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2023
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14. An Objective Structured Laboratory Animal Science Examination (OSLASE) to ensure researchers' professional competence in laboratory animal science.
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Costa A, Lamas S, Correia MR, Gomes MS, Costa MJ, and Olsson IAS
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- Animals, Clinical Competence, Reproducibility of Results, Professional Competence, Animals, Laboratory, Laboratory Animal Science
- Abstract
The evaluation of the competence of personnel working with laboratory animals is currently a challenge. Directive 2010/63/EU establishes that staff must have demonstrated competence before they perform unsupervised work with living animals. Nevertheless, there is a lack of research into education and training in laboratory animal science, and the establishment of assessment strategies to confirm researchers' competence remains largely unaddressed.In this study, we analysed the implementation of a practical assessment strategy over three consecutive years (2018-2021) using the Objective Structured Laboratory Animal Science Exam (OSLASE) developed previously by us to assess professional competence. The interrater reliability (IRR) was determined based on the assessors' rating of candidates' performance at different OSLASE stations using weighted kappa (Kw) and percentage of agreement. Focus group interviews were conducted to access trainees' acceptability regarding the OSLASE.There was a moderate-to-good Kw for the majority of the scales' items (0.79 ± 0.20 ≤ Kw ≥ 0.45 ± 0.13). The percentages of agreement were also acceptable (≥75%) for all scale items but one. Trainees reported that the OSLASE had a positive impact on their engagement during practical training, and that it clarified the standards established for their performance and the skills that required improvement. These preliminary results illustrate how assessment strategies, such as the OSLASE, can be implemented in a manner that is useful for both assessors and trainees.Examen structuré objectif de science animale de laboratoire (OSASSE) pour assurer la compétence professionnelle des chercheurs en SAL.
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- 2023
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15. Biocompatible Parylene-C Laser-Induced Graphene Electrodes for Microsupercapacitor Applications.
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Correia R, Deuermeier J, Correia MR, Vaz Pinto J, Coelho J, Fortunato E, and Martins R
- Abstract
Laser irradiation of polymeric materials has drawn great attention as a fast, simple, and cost-effective method for the formation of porous graphene films that can be subsequently fabricated into low-cost and flexible electronic and energy-storage devices. In this work, we report a systematic study of the formation of laser-induced graphene (LIG) with sheet resistances as low as 9.4 Ω/sq on parylene-C ultrathin membranes under a CO
2 infrared laser. Raman analysis proved the formation of the multilayered graphenic material, with ID / IG and I2D / IG peak ratios of 0.42 and 0.65, respectively. As a proof of concept, parylene-C LIG was used as the electrode material for the fabrication of ultrathin, solid-state microsupercapacitors (MSCs) via a one-step, scalable, and cost-effective approach, aiming at future flexible and wearable applications. The produced LIG-MSC on parylene-C exhibited good electrochemical behavior, with a specific capacitance of 1.66 mF/cm2 and an excellent cycling stability of 96% after 10 000 cycles (0.5 mA/cm2 ). This work allows one to further extend the knowledge in LIG processes, widening the group of precursor materials as well as promoting future applications. Furthermore, it reinforces the potential of parylene-C as a key material for next-generation biocompatible and flexible electronic devices.- Published
- 2022
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16. Mediastinal Teratoma In Children - Case Report.
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Barbosa-Sequeira J, Correia MR, Carvalho C, Paupério G, and Carvalho F
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- Child, Humans, Physical Examination, Postoperative Period, Mediastinal Neoplasms diagnosis, Teratoma diagnosis
- Abstract
Mediastinal teratomas presenting in the pediatric age are extremely rare. We report three cases of mediastinal teratomas in children aged 15 months to 9 years. Patients were submitted to complete tumor resection, with an uneventful postoperative course and follow-up. Our report emphasizes the importance of a detailed patient examination and careful interpretation of routinely performed image studies.
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- 2022
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17. Impact of atomic layer deposited TiO 2 on the photocatalytic efficiency of TiO 2 /w-VA-CNT nanocomposite materials.
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Oliveira IE, Silva RM, Rodrigues J, Correia MR, Monteiro T, Faria JL, Silva RF, and Silva CG
- Abstract
Titanium oxide (TiO
2 ) has been widely investigated as a photocatalytic material, and the fact that its performance depends on its crystalline structure motivates further research on the relationship between preparation methods and material properties. In this work, TiO2 thin films were grown on non-functionalized wave-like patterned vertically aligned carbon nanotubes (w-VA-CNTs) via the atomic layer deposition (ALD) technique. Grazing incidence X-ray diffraction (GIXRD) analysis revealed that the structure of the TiO2 /VA-CNT nanocomposites varied from amorphous to a crystalline phase with increasing deposition temperature, suggesting a "critical deposition temperature" for the anatase crystalline phase formation. On the other hand, scanning transmission electron microscopy (STEM) studies revealed that the non-functionalized carbon nanotubes were conformally and homogeneously coated with TiO2 , forming a nanocomposite while preserving the morphology of the nanotubes. X-ray photoelectron spectroscopy (XPS) provided information about the surface chemistry and stoichiometry of TiO2 . The photodegradation experiments under ultraviolet (UV) light on a model pollutant (Rhodamine B, RhB) revealed that the nanocomposite comprised of anatase crystalline TiO2 grown at 200 °C (11.2 nm thickness) presented the highest degradation efficiency viz 55% with an illumination time of 240 min. Furthermore, its recyclability was also demonstrated for multiple cycles, showing good recovery and potential for practical applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2022
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18. Compensatory sweating after thoracoscopic sympathectomy for primary focal hyperhidrosis in children: Are there patient-related risk factors?
- Author
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Carvalho C, Marinho AS, Barbosa-Sequeira J, Correia MR, Banquart-Leitão J, and Carvalho F
- Subjects
- Child, Female, Humans, Patient Satisfaction, Retrospective Studies, Risk Factors, Sympathectomy, Thoracoscopy adverse effects, Treatment Outcome, Hyperhidrosis etiology, Hyperhidrosis surgery, Sweating
- Abstract
Introduction: Compensatory sweating (CS) is a common complication after thoracoscopic sympathectomy (TS) and is mainly associated with surgical technique. Our aim was to identify potential risk-factors for CS following TS for primary focal hyperhidrosis in children., Methods: A retrospective, single-center review of all bilateral TS was performed between 2017 and 2019. Hyperhidrosis disease severity scale was used for pre-operative severity assessment. Post-operative evaluations were performed after three and six months., Results: More than the 36-month period, 41 patients were submitted to T2-T4 TS, and 25 were females (60.9%). Median age at surgery was 15.5 years. CS was identified at the 3rd month in 17 (41%) children with most in the dorsolumbar region (56%). By the 6th month, there was a significant reduction in CS (41 to 32%, p = 0.02). The probability of resolution of CS by 6 months is about 50% in both the dorsolumbar and abdominal regions. Neither age, gender, body mass index, family history, or concomitant illnesses seemed to influence CS (p > 0.05). Axillary hyperhidrosis appears to be associated with the development of dorsolumbar CS (p = 0.037)., Conclusion: Thoracoscopic sympathectomy for PFH is a safe and effective procedure, but compensatory sweating can be a common and debilitating side effect. Age, gender, and body mass index do not appear to influence CS. Axillary hyperhidrosis may be related to the development of dorsolumbar CS., Level of Evidence: III., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest relevant to this article to disclose., (Copyright © 2021. Published by Elsevier Inc.)
- Published
- 2022
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19. Pediatric Burns With Cyanoacrylate Glue: An Inconspicuous Danger.
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Carvalho C, Marinho AS, Barbosa-Sequeira J, Correia MR, Carvalho F, Banquart-Leitão J, and Morgado H
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- Burns, Chemical therapy, Child, Child, Preschool, Female, Follow-Up Studies, Humans, Lower Extremity, Male, Skin Care methods, Adhesives adverse effects, Burns, Chemical etiology, Cyanoacrylates adverse effects, Household Products adverse effects
- Abstract
Burns are a common cause of pediatric injury and represent significant morbidity and mortality in this age group. In children, most burns are thermal, resulting from exposure to a hot surface, liquid, or fire. Cyanoacrylate is a liquid compound commonly found in households, mainly in "superglue" and nail glue. This compound solidifies through an exothermic reaction that is magnified when in contact with certain fibers that act as catalysts, such as cotton. In these circumstances, intense heat is produced in the contact area, potentially causing severe thermal burns. Despite its widespread availability, there is a paucity of safety information about cyanoacrylate and its role as a cause for burns. In the literature, only 18 cases of cyanoacrylate burns are reported in children. We present two cases of pediatric burns with cyanoacrylate and a review of the literature., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Burn Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2021
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20. ZnAl 2 O 4 decorated Al-doped ZnO tetrapodal 3D networks: microstructure, Raman and detailed temperature dependent photoluminescence analysis.
- Author
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Rodrigues J, Hoppe M, Ben Sedrine N, Wolff N, Duppel V, Kienle L, Adelung R, Mishra YK, Correia MR, and Monteiro T
- Abstract
3D networks of Al-doped ZnO tetrapods decorated with ZnAl
2 O4 particles synthesised by the flame transport method were investigated in detail using optical techniques combined with morphological/structural characterisation. Low temperature photoluminescence (PL) measurements revealed spectra dominated by near band edge (NBE) recombination in the UV region, together with broad visible bands whose peak positions shift depending on the ZnO : Al mixing ratios. A close inspection of the NBE region evidences the effective doping of the ZnO structures with Al, as corroborated by the broadening and shift of its peak position towards the expected energy associated with the exciton bound to Al. Both temperature and excitation density-dependent PL results pointed to an overlap of multiple optical centres contributing to the broad visible band, with the peak position dependent on the Al content. While in the reference sample the wavelength of the green band remained unchanged with temperature, in the case of the composites, the deep level emission showed a blue shift with increasing temperature, likely due to distinct thermal quenching of the overlapping emitting centres. This assumption was further validated by the time-resolved PL data, which clearly exposed the presence of more than one optical centre in this spectral region. PL excitation analysis demonstrated that the luminescence features of the Al-doped ZnO/ZnAl2 O4 composites revealed noticeable changes not only in deep level recombination, but also in the material's bandgap when compared with the ZnO reference sample. At room temperature, the ZnO reference sample exhibited free exciton resonance at ∼3.29 eV, whereas the peak position for the Al-doped ZnO/ZnAl2 O4 samples occurred at ∼3.38 eV due to the Burstein-Moss shift, commonly observed in heavily doped semiconductors. Considering the energy shift observed and assuming a parabolic conduction band, a carrier concentration of ∼1.82 ×1019 cm-3 was estimated for the Al-doped ZnO/ZnAl2 O4 samples., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2020
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21. Probing surface states in C 60 decorated ZnO microwires: detailed photoluminescence and cathodoluminescence investigations.
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Rodrigues J, Smazna D, Ben Sedrine N, Nogales E, Adelung R, Mishra YK, Mendez B, Correia MR, and Monteiro T
- Abstract
ZnO microwires synthesised by the flame transport method and decorated with C
60 clusters were studied in detail by photoluminescence (PL) and cathodoluminescence (CL) techniques. The optical investigations suggest that the enhanced near band edge recombination observed in the ZnO/C60 composites is attributed to the reduction of the ZnO band tail states in the presence of C60 . Well-resolved free and bound excitons recombination, as well as 3.31 eV emission, are observed with increasing amount of C60 flooding when compared with the ZnO reference sample. Moreover, a shift of the broad visible emission to lower energies occurs with increasing C60 content. In fact, this band was found to be composed by two optical centres peaked in the green and orange/red spectral regions, presenting different lifetimes. The orange/red band exhibits faster lifetime decay, in addition to a more pronounced shift to lower energies, while the peak position of the green emission only shows a slight change. The overall redshift of the broad visible band is further enhanced by the change in the relative intensity of the mentioned optical centres, depending on the excitation intensity and on the C60 flooding. These results suggest the possibility of controlling/tuning the visible emission outcome by increasing the C60 amount on the ZnO surface due to the surface states present in the semiconductor. An adequate control of such phenomena may have quite beneficial implications when sensing applications are envisaged., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2019
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22. Hierarchical Aerographite 3D flexible networks hybridized by InP micro/nanostructures for strain sensor applications.
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Plesco I, Strobel J, Schütt F, Himcinschi C, Ben Sedrine N, Monteiro T, Correia MR, Gorceac L, Cinic B, Ursaki V, Marx J, Fiedler B, Mishra YK, Kienle L, Adelung R, and Tiginyanu I
- Abstract
In the present work, we report on development of three-dimensional flexible architectures consisting of an extremely porous three-dimensional Aerographite (AG) backbone decorated by InP micro/nanocrystallites grown by a single step hydride vapor phase epitaxy process. The systematic investigation of the hybrid materials by scanning electron microscopy demonstrates a rather uniform spatial distribution of InP crystallites without agglomeration on the surface of Aerographite microtubular structures. X-ray diffraction, transmission electron microscopy and Raman scattering analysis demonstrate that InP crystallites grown on bare Aerographite are of zincblende structure, while a preliminary functionalization of the Aerographite backbone with Au nanodots promotes the formation of crystalline In
2 O3 nanowires as well as gold-indium oxide core-shell nanostructures. The electromechanical properties of the hybrid AG-InP composite material are shown to be better than those of previously reported bare AG and AG-GaN networks. Robustness, elastic behavior and excellent translation of the mechanical deformation to variations in electrical conductivity highlight the prospects of AG-InP applications in tactile/strain sensors and other device structures related to flexible electronics.- Published
- 2018
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23. Effect of the Chloride Anions on the Formation of Self-Assembled Diphenylalanine Peptide Nanotubes.
- Author
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Dayarian S, Kopyl S, Bystrov V, Correia MR, Ivanov MS, Pelegova E, and Kholkin A
- Subjects
- Dipeptides, Hydrogen-Ion Concentration, Models, Molecular, Phenylalanine chemistry, Anions chemistry, Chlorides chemistry, Nanotubes, Peptide chemistry, Phenylalanine analogs & derivatives
- Abstract
Self-assembled peptide nanostructures are being intensively investigated due to their potential applications such as biosensors, piezotransducers, and microactuators. It was predicted that their formation and hence piezoelectric property strongly depend on the water content and acidity of the stock solution. In this paper, simple diphenylalanine (FF) tubular structures were fabricated from the solutions with added hydrochloric acid in order to understand the influence of chloride ions on the self-assembly process and resulting piezoelectricity. Low-frequency Raman scattering, atomic, and piezoresponse force microscopies were used to characterize both the morphology and piezoelectric properties of the grown samples. The mechanism of chloride anions' effect on the formation of self-assembled peptide nanostructures is discussed based on the acquired Raman data and quantum-chemical modeling. It is shown that the addition of chloride anions causes a significant reduction of the dipole moments of FF tubes accompanied with the concomitant decrease of tube dimensions and apparent shear piezoelectric coefficients.
- Published
- 2018
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24. Buckminsterfullerene hybridized zinc oxide tetrapods: defects and charge transfer induced optical and electrical response.
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Smazna D, Rodrigues J, Shree S, Postica V, Neubüser G, Martins AF, Ben Sedrine N, Jena NK, Siebert L, Schütt F, Lupan O, Ahuja R, Correia MR, Monteiro T, Kienle L, Yang Y, Adelung R, and Mishra YK
- Abstract
Buckminster fullerene (C60) based hybrid metal oxide materials are receiving considerable attention because of their excellent fundamental and applied aspects, like semiconducting, electron transfer, luminescent behaviors, etc. and this work briefly discusses the successful fabrication of C60 decorated ZnO tetrapod materials and their detailed structure-property relationships including device sensing applications. The electron microscopy investigations indicate that a quite dense surface coverage of ZnO tetrapods with C60 clusters is achieved. The spectroscopy studies confirmed the identification of the C60 vibrational modes and the C60 induced changes in the absorption and luminescence properties of the ZnO tetrapods. An increased C60 concentration on ZnO results in steeper ZnO bandgap absorption followed by well-defined free exciton and 3.31 eV line emissions. As expected, higher amounts of C60 increase the intensity of C60-related visible absorption bands. Pumping the samples with photons with an energy corresponding to these absorption band maxima leads to additional emission from ZnO showing an effective charge transfer phenomenon from C60 to the ZnO host. The density of states model obtained from DFT studies for pure and C60 coated ZnO surfaces confirms the experimental observations. The fabricated C60-ZnO hybrid tetrapod based micro- and nanodevices showed interesting ethanol gas sensing characteristics.
- Published
- 2018
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25. Fluctuating potentials in GaAs:Si nanowires: critical reduction of the influence of polytypism on the electronic structure.
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Ben Sedrine N, Ribeiro-Andrade R, Gustafsson A, Soares MR, Bourgard J, Teixeira JP, Salomé PMP, Correia MR, Moreira MVB, De Oliveira AG, González JC, and Leitão JP
- Abstract
In this work, the effects of Si doping in GaAs nanowires (NWs) grown on GaAs (111)B by molecular beam epitaxy with different Si doping levels (nominal free carrier concentrations of 1 × 10
16 , 8 × 1016 , 1 × 1018 and 5 × 1018 cm-3 ) are deeply investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), grazing incidence X-ray diffraction (GID), photoluminescence (PL) and cathadoluminescence (CL). TEM results reveal a mixture of wurtzite (WZ) and zinc-blende (ZB) segments along the NW axis independently of the Si doping levels. GID measurements suggest a slight increase of the ZB fraction with the Si doping. Low temperature PL and CL spectra exhibit sharp lines in the energy range 1.41-1.48 eV, for the samples with lower Si doping levels. However, the emission intensity increases and is accompanied by a clear broadening of the observed lines for the samples with higher Si doping levels. The staggered type-II band alignment only determines the optical properties of the lower doping levels in GaAs:Si NWs. For the higher Si doping levels, the electronic energy level structure of the NWs is determined by electrostatic fluctuating potentials intimately related to the amphoteric behavior of the Si dopant in GaAs. For the heavily doped NWs, the estimated depth of the potential wells is ∼96-117 meV. Our results reveal that the occurrence of the fluctuating potentials is not dependent on the crystalline phase and shows that the limitation imposed by the polytypism can be overcome.- Published
- 2018
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26. Substrate and Mg doping effects in GaAs nanowires.
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Kannappan P, Sedrine NB, Teixeira JP, Soares MR, Falcão BP, Correia MR, Cifuentes N, Viana ER, Moreira MVB, Ribeiro GM, de Oliveira AG, González JC, and Leitão JP
- Abstract
Mg doping of GaAs nanowires has been established as a viable alternative to Be doping in order to achieve p-type electrical conductivity. Although reports on the optical properties are available, few reports exist about the physical properties of intermediate-to-high Mg doping in GaAs nanowires grown by molecular beam epitaxy (MBE) on GaAs(111)B and Si(111) substrates. In this work, we address this topic and present further understanding on the fundamental aspects. As the Mg doping was increased, structural and optical investigations revealed: i) a lower influence of the polytypic nature of the GaAs nanowires on their electronic structure; ii) a considerable reduction of the density of vertical nanowires, which is almost null for growth on Si(111); iii) the occurrence of a higher WZ phase fraction, in particular for growth on Si(111); iv) an increase of the activation energy to release the less bound carrier in the radiative state from nanowires grown on GaAs(111)B; and v) a higher influence of defects on the activation of nonradiative de-excitation channels in the case of nanowires only grown on Si(111). Back-gate field effect transistors were fabricated with individual nanowires and the p-type electrical conductivity was measured with free hole concentration ranging from 2.7 × 10
16 cm-3 to 1.4 × 1017 cm-3 . The estimated electrical mobility was in the range ≈0.3-39 cm2 / Vs and the dominant scattering mechanism is ascribed to the WZ/ZB interfaces. Electrical and optical measurements showed a lower influence of the polytypic structure of the nanowires on their electronic structure. The involvement of Mg in one of the radiative transitions observed for growth on the Si(111) substrate is suggested.- Published
- 2017
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27. "That Should Be Left to Doctors, That's What They are There For!"-Exploring the Reflexivity and Trust of Young Adults When Seeking Health Information.
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Mendes Á, Abreu L, Vilar-Correia MR, and Borlido-Santos J
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- Female, Humans, Internet standards, Internet statistics & numerical data, Male, Qualitative Research, Reproducibility of Results, Consumer Health Information statistics & numerical data, Information Seeking Behavior, Physicians standards, Trust
- Abstract
This paper explores the health information-seeking practices of healthy young adults and how they assess and rank sources of information through a qualitative study. The findings show that participants (a) are strongly committed to searching for information about health and lifestyle, especially via the Internet; (b) healthcare professionals were perceived as the most reliable source of health information and advice; (c) online health information, although frequently accessed and experienced as empowering, is seen as a potentially unreliable source. Findings evidence how becoming better informed about health-related topics plays a pivotal role in individuals' lives, most notably by using the Internet. Participants were able to reflect about what it means to know about health. The construction of trust regarding health information involved a heuristic process vis-à-vis source reliability and perceived credibility that places doctors as the most trustworthy medium of medical advice and health information. We conclude that participants' trust toward professionals suggests the preference and need for more personalized care; and it is a response to the ambiguity and uncertainty that permeates the health information landscape, particularly that which is web-based.
- Published
- 2017
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28. SiGe layer thickness effect on the structural and optical properties of well-organized SiGe/SiO 2 multilayers.
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Vieira EMF, Toudert J, Rolo AG, Parisini A, Leitão JP, Correia MR, Franco N, Alves E, Chahboun A, Martín-Sánchez J, Serna R, and Gomes MJM
- Abstract
In this work, we report on the production of regular (SiGe/SiO
2 )20 multilayer structures by conventional RF-magnetron sputtering, at 350 °C. Transmission electron microscopy, scanning transmission electron microscopy, raman spectroscopy, and x-ray reflectometry measurements revealed that annealing at a temperature of 1000 °C leads to the formation of SiGe nanocrystals between SiO2 thin layers with good multilayer stability. Reducing the nominal SiGe layer thickness (tSiGe ) from 3.5-2 nm results in a transition from continuous SiGe crystalline layer (tSiGe ∼ 3.5 nm) to layers consisting of isolated nanocrystals (tSiGe ∼ 2 nm). Namely, in the latter case, the presence of SiGe nanocrystals ∼3-8 nm in size, is observed. Spectroscopic ellipsometry was applied to determine the evolution of the onset in the effective optical absorption, as well as the dielectric function, in SiGe multilayers as a function of the SiGe thickness. A clear blue-shift in the optical absorption is observed for tSiGe ∼ 2 nm multilayer, as a consequence of the presence of isolated nanocrystals. Furthermore, the observed near infrared values of n = 2.8 and k = 1.5 are lower than those of bulk SiGe compounds, suggesting the presence of electronic confinement effects in the nanocrystals. The low temperature (70 K) photoluminescence measurements performed on annealed SiGe/SiO2 nanostructures show an emission band located between 0.7-0.9 eV associated with the development of interface states between the formed nanocrystals and surrounding amorphous matrix.- Published
- 2017
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29. Structure and Electrical-Transport Relations in Ba(Zr,Pr)O 3-δ Perovskites.
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Antunes I, Amador U, Alves A, Correia MR, Ritter C, Frade JR, Pérez-Coll D, Mather GC, and Fagg DP
- Abstract
Members of the perovskite solid solution BaZr
1-x Prx O3-δ (0.2 ≤ x ≤ 0.8) with potential high-temperature electrochemical applications were synthesized via mechanical activation and high-temperature annealing at 1250 °C. Structural properties were examined by Rietveld analysis of neutron powder diffraction and Raman spectroscopy at room temperature, indicating rhombohedral symmetry (space group R3̅c) for members x = 0.2 and 0.4 and orthorhombic symmetry (Imma) for x = 0.6 and 0.8. The sequence of phase transitions for the complete solid solution from BaZrO3 to BaPrO3 is Pm3̅m → R3̅c → Imma → Pnma. The structural data indicate that Pr principally exists as Pr4+ on the B site and that oxygen content increases with higher Pr content. Electrical-conductivity measurements in the temperature range of 250-900 °C in dry and humidified (pH2 O ≈ 0.03 atm) N2 and O2 atmospheres revealed an increase of total conductivity by over 2 orders of magnitude in dry conditions from x = 0.2 to x = 0.8 (σ ≈ 0.08 S cm-1 at 920 °C in dry O2 for x = 0.8). The conductivity for Pr contents x > 0.2 is attributable to positively charged electronic carriers, whereas for x = 0.2 transport in dry conditions is n-type. The change in conduction mechanism with composition is proposed to arise from the compensation regime for minor amounts of BaO loss changing from predominantly partitioning of Pr on the A site to vacancy formation with increasing Pr content. Conductivity is lower in wet conditions for x > 0.2 indicating that the positive defects are, to a large extent, charge compensated by less mobile protonic species. In contrast, the transport mechanism of the Zr-rich composition (x = 0.2), with much lower electronic conductivity, is essentially independent of moisture content.- Published
- 2017
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30. Importance of Zinc Transporter 8 Autoantibody in the Diagnosis of Type 1 Diabetes in Latin Americans.
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Gomes KF, Semzezem C, Batista R, Fukui RT, Santos AS, Correia MR, Passos-Bueno MR, and Silva ME
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- Adolescent, Adult, Brazil ethnology, Cohort Studies, Diabetes Mellitus, Type 1 ethnology, Diabetes Mellitus, Type 1 genetics, Diabetes Mellitus, Type 1 immunology, Female, Genetic Association Studies, Genetic Predisposition to Disease, Genotype, Glutamate Decarboxylase immunology, Humans, Male, Receptor-Like Protein Tyrosine Phosphatases, Class 8 immunology, White People genetics, Young Adult, Autoantibodies metabolism, Diabetes Mellitus, Type 1 diagnosis, Polymorphism, Single Nucleotide, Zinc Transporter 8 genetics, Zinc Transporter 8 immunology
- Abstract
There is a scarcity of data of zinc transporter-8 autoantibody (ZnT8A) on mixed populations such as Brazilian. Therefore, we evaluated the relevance of ZnT8A for type 1 diabetes (T1D) diagnosis and the role of ZnT8 coding gene (SLC30A8) in T1D predisposition. Patients with T1D (n = 629; diabetes duration = 11 (6-16) years) and 651 controls were genotyped for SLC30A8 rs16889462 and rs2466295 variants (BeadXpress platform). ZnT8 triple antibody was measured by ELISA; glutamic acid decarboxylase (GAD65A) and protein tyrosine phosphatase (IA-2A) autoantibodies by radioimmunoassay., Results: Znt8A was detected in 68.7% of recent-onset T1D patients and 48.9% of the entire patient cohort, similar to GAD65A (68.3% and 47.2%) and IA-2A (64.8% and 42.4%) positivities respectively. ZnT8A was the only antibody in 8.4% of patients. Znt8A and IA2A frequencies and titers were independent of gender and ethnicity, whereas GAD65A titers were greater in females. The diabetes duration-dependent decline in ZnT8A frequency was similar to GAD65A and IA-2A. The SLC30A8 rs2466293 AG + GG genotypes were associated with T1D risk in non-European descents (56.2% × 42.9%; p = 0.018), and the GG genotype with higher ZnT8A titers in recent-onset T1D: 834.5 IU/mL (711.3-2190.0) × 281 IU/mL (10.7-726.8); p = 0.027. Conclusion ZnT8A detection increases T1D diagnosis rate even in mixed populations. SLC30A8 rs2466293 was associated with T1D predisposition in non-European descents.
- Published
- 2017
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31. The influence of population stratification on genetic markers associated with type 1 diabetes.
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Gomes KF, Santos AS, Semzezem C, Correia MR, Brito LA, Ruiz MO, Fukui RT, Matioli SR, Passos-Bueno MR, and Silva ME
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- Adolescent, Adult, Alleles, Case-Control Studies, Child, Diabetes Mellitus, Type 1 diagnosis, Female, Gene Frequency, Genotype, HLA Antigens genetics, Humans, Male, Odds Ratio, Population Surveillance, Young Adult, Diabetes Mellitus, Type 1 epidemiology, Diabetes Mellitus, Type 1 genetics, Genetic Association Studies, Genetic Markers, Genetic Predisposition to Disease
- Abstract
Ethnic admixtures may interfere with the definition of type 1 diabetes (T1D) risk determinants. The role of HLA, PTPN22, INS-VNTR, and CTLA4 in T1D predisposition was analyzed in Brazilian T1D patients (n = 915), with 81.7% self-reporting as white and 789 controls (65.6% white). The results were corrected for population stratification by genotyping 93 ancestry informative markers (AIMs) (BeadXpress platform). Ancestry composition and structural association were characterized using Structure 2.3 and STRAT. Ethnic diversity resulted in T1D determinants that were partially discordant from those reported in Caucasians and Africans. The greatest contributor to T1D was the HLA-DR3/DR4 genotype (OR = 16.5) in 23.9% of the patients, followed by -DR3/DR3 (OR = 8.9) in 8.7%, -DR4/DR4 (OR = 4.7) in 6.0% and -DR3/DR9 (OR = 4.9) in 2.6%. Correction by ancestry also confirmed that the DRB1*09-DQB1*0202 haplotype conferred susceptibility, whereas the DRB1*07-DQB1*0202 and DRB1*11-DQB1*0602 haplotypes were protective, which is similar to reports in African-American patients. By contrast, the DRB1*07-DQB1*0201 haplotype was protective in our population and in Europeans, despite conferring susceptibility to Africans. The DRB1*10-DQB1*0501 haplotype was only protective in the Brazilian population. Predisposition to T1D conferred by PTPN22 and INS-VNTR and protection against T1D conferred by the DRB1*16 allele were confirmed. Correcting for population structure is important to clarify the particular genetic variants that confer susceptibility/protection for T1D in populations with ethnic admixtures.
- Published
- 2017
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32. Hybridization of Zinc Oxide Tetrapods for Selective Gas Sensing Applications.
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Lupan O, Postica V, Gröttrup J, Mishra AK, de Leeuw NH, Carreira JF, Rodrigues J, Ben Sedrine N, Correia MR, Monteiro T, Cretu V, Tiginyanu I, Smazna D, Mishra YK, and Adelung R
- Abstract
In this work, the exceptionally improved sensing capability of highly porous three-dimensional (3-D) hybrid ceramic networks toward reducing gases is demonstrated for the first time. The 3-D hybrid ceramic networks are based on doped metal oxides (Me
x Oy and Znx Me1-x Oy , Me = Fe, Cu, Al) and alloyed zinc oxide tetrapods (ZnO-T) forming numerous junctions and heterojunctions. A change in morphology of the samples and formation of different complex microstructures is achieved by mixing the metallic (Fe, Cu, Al) microparticles with ZnO-T grown by the flame transport synthesis (FTS) in different weight ratios (ZnO-T:Me, e.g., 20:1) followed by subsequent thermal annealing in air. The gas sensing studies reveal the possibility to control and change/tune the selectivity of the materials, depending on the elemental content ratio and the type of added metal oxide in the 3-D ZnO-T hybrid networks. While pristine ZnO-T networks showed a good response to H2 gas, a change/tune in selectivity to ethanol vapor with a decrease in optimal operating temperature was observed in the networks hybridized with Fe-oxide and Cu-oxide. In the case of hybridization with ZnAl2 O4 , an improvement of H2 gas response (to ∼7.5) was reached at lower doping concentrations (20:1), whereas the increase in concentration of ZnAl2 O4 (ZnO-T:Al, 10:1), the selectivity changes to methane CH4 gas (response is about 28). Selectivity tuning to different gases is attributed to the catalytic properties of the metal oxides after hybridization, while the gas sensitivity improvement is mainly associated with additional modulation of the electrical resistance by the built-in potential barriers between n-n and n-p heterojunctions, during adsorption and desorption of gaseous species. Density functional theory based calculations provided the mechanistic insights into the interactions between different hybrid networks and gas molecules to support the experimentally observed results. The studied networked materials and sensor structures performances would provide particular advantages in the field of fundamental research, applied physics studies, and industrial and ecological applications.- Published
- 2017
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33. Site Redistribution, Partial Frozen-in Defect Chemistry, and Electrical Properties of Ba1-x(Zr,Pr)O3-δ.
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Antunes I, Mikhalev S, Mather GC, Kharton VV, Figueiras FG, Alves A, Rodrigues J, Correia MR, Frade JR, and Fagg DP
- Abstract
Changes in nominal composition of the perovskite (ABO3) solid solution Ba1-x(Zr,Pr)O3-δ and adjusted firing conditions at very high temperatures were used to induce structural changes involving site redistribution and frozen-in point defects, as revealed by Raman and photoluminescence spectroscopies. Complementary magnetic measurements allowed quantification of the reduced content of Pr. Weak dependence of oxygen stoichiometry with temperature was obtained by coulometric titration at temperatures below 1000 °C, consistent with a somewhat complex partial frozen-in defect chemistry. Electrical conductivity measurements combined with transport number and Seebeck coefficient measurements showed prevailing electronic transport and also indicated trends expected for partial frozen-in conditions. Nominal Ba deficiency and controlled firing at very high temperatures allows adjustment of structure and partial frozen-in defect chemistry, opening the way to engineer relevant properties for high-temperature electrochemical applications.
- Published
- 2016
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34. How Effective Is the Quadruple Concomitant Helicobacter Pylori Eradication Therapy for Obese Patients Undergoing Gastric Bypass Surgery?
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Cerqueira RM, Correia MR, Vilar H, and Manso MC
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- Adolescent, Adult, Amoxicillin administration & dosage, Amoxicillin therapeutic use, Anti-Bacterial Agents administration & dosage, Clarithromycin administration & dosage, Clarithromycin therapeutic use, Cohort Studies, Drug Therapy, Combination, Female, Gastric Bypass, Helicobacter Infections complications, Helicobacter Infections microbiology, Helicobacter pylori drug effects, Humans, Male, Metronidazole administration & dosage, Metronidazole therapeutic use, Middle Aged, Obesity, Morbid complications, Portugal, Prospective Studies, Proton Pump Inhibitors administration & dosage, Proton Pump Inhibitors therapeutic use, Treatment Outcome, Young Adult, Anti-Bacterial Agents therapeutic use, Helicobacter Infections drug therapy, Obesity, Morbid surgery
- Abstract
Aims and Methods: Our aim was to assess, in obese patients undergoing Roux-en Y gastric bypass surgery, the quadruple concomitant HP eradication rates at first line treatment as proposed by the Maastricht IV consensus in areas of high clarithromycin resistance rates-proton pump inhibitor bid, clarithromycin 500 mg bid, amoxicillin 1000 mg bid, and metronidazole 500 mg bid. This is a single center prospective study over a 3-year period. Endoscopy and HP assessment (by histology or C13 urea breath) were performed at baseline, and post treatment HP status was assessed by C13 urea breath test 4-6 weeks after the end of therapy., Results: The study cohort consisted of 600 adult obese HP positive patients [19 % male/81 % female, age 40.7 (±10.4) years] consecutively scheduled for HP concomitant therapy. HP was eradicated in 416 patients [69.3 % (95% CI 65.5-72.9 %)] and the eradication was independent of gender, age, endoscopic diagnosis, and smoking status (p > 0.05)., Conclusions: Two weeks quadruple concomitant therapy did not achieve Maastricht recommended first line acceptable HP eradication rates (at least 80 %) in obese Portuguese patients undergoing GB.
- Published
- 2016
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35. Effects of nateglinide and rosiglitazone on pancreatic alpha- and beta-cells, GLP-1 secretion and inflammatory markers in patients with type 2 diabetes: randomized crossover clinical study.
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Tostes GC, Cunha MR, Fukui RT, Correia MR, Rocha DM, Dos Santos RF, and da Silva ME
- Abstract
Background: To compare the effects of nateglinide and rosiglitazone on inflammatory markers, GLP-1 levels and metabolic profile in patients with type 2 diabetes (DM2)., Methods: A prospective study was performed in 20 patients with DM2, mean age 51.82 ± 8.05 years, previously treated with dietary intervention. Participants were randomized into rosiglitazone (4-8 mg/day) or nateglinide (120 mg 3 times a day) therapy. After 4 months, the patients were crossed-over with 8 weeks washout period to the alternative treatment for an additional 4-month period on similar dosage schedule. The following variables were assessed before and after 4 months of each treatment period: (1) a test with a standardized 500 calories meal for 5 h including frequent measurements of glucose, insulin, glucagon, proinsulin, GLP-1, free fat acids (FFA), and triglycerides levels was obtained. The lipid profile and HbA1 levels were measured at fasting. (2) Haemostatic and inflammatory markers: platelet aggregation, fibrinogen, PAI-1 activity, C reactive protein (CRP), IL-6, TNF-α, leptin, sICAM and TGFβ levels., Results: Both therapy decreased blood glucose levels under the postprandial curve but neither affected glucagon and GLP-1 levels. Nateglinide was associated with higher insulin and pro-insulin secretion, but similar pro-insulin/insulin ratio when compared with rosiglitazone. Only rosiglitazone decreased Homa β, PAI-1 activity, CRP, fibrinogen, TGFβ, FFA and triglyceride levels., Conclusions: Nateglinide and rosiglitazone were effective in improving glucose and lipid profile and β cell function, but rosiglitazone afforded a better anti-inflammatory effect. No drug restored alpha cell sensitivity or changed GLP-1 levels. Maintenance of haemostatic factors, inflammatory factors and glucagon levels can be related to the continuously worsening of cardiovascular function and glucose control observed in DM2.
- Published
- 2016
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36. Short and Long Term Effects of a DPP-4 Inhibitor Versus Bedtime NPH Insulin as ADD-ON Therapy in Patients with Type 2 Diabetes.
- Author
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da Silva GM, Nogueira KC, Fukui RT, Correia MR, Dos Santos RF, and da Silva ME
- Subjects
- Blood Glucose metabolism, C-Peptide blood, Dipeptidyl-Peptidase IV Inhibitors administration & dosage, Female, Glucose administration & dosage, Humans, Insulin administration & dosage, Male, Middle Aged, Prospective Studies, Sitagliptin Phosphate administration & dosage, Triglycerides blood, Diabetes Mellitus, Type 2 drug therapy, Dipeptidyl-Peptidase IV Inhibitors therapeutic use, Insulin therapeutic use, Sitagliptin Phosphate therapeutic use
- Abstract
Background: We conducted a comparison between the dipeptidyl-peptidase-4(DPP-4) inhibitor sitagliptin versus NPH insulin as an add-on therapies in patients with type 2 diabetes mellitus (T2D) failing oral medications. The objective was to ascertain the better indication in long-duration diabetes., Methods: thirty-five T2D patients inadequately controlled with metformin plus glyburide were randomized to receive sitagliptin (n=18) or bedtime NPH insulin (n=17) for 12 months. HbA1c levels and a metabolic and hormonal profile at fasting and post-meal (every 30 minutes for 4 hours) were evaluated before and after 6 months (short-term) and 12 months (long-term) after adding sitagliptin or bedtime NPH insulin to their drug regime., Results: Sitagliptin and NPH insulin decreased HbA1c levels equally after 6 months (p<0.001) with no further improvement after 12 months: sitagliptin (8.1±0.7% vs. 7.3±0.8% vs. 7.4±1.9%) and insulin (8.1±0.6% vs. 7.3±0.7% vs. 7.2±1.0%). Fasting glucose, fasting and postprandial triglyceride and C-peptide levels were also reduced by NPH insulin whereas postprandial insulin was decreased by sitagliptin. Body weight and postchallenge free fatty acid levels increased with insulin treatment. The transitory suppression (at 6 months) of postprandial proinsulin levels with both therapies, and of glucagon with sitagliptin, was followed by values similar or worse to those at pre-treatment., Conclusion: The use of either NPH insulin or a DPP-4 inhibitor as add-on treatments improves glucose control in patients with T2D failing on metformin plus glyburide therapy. The results were not attributed to a permanent improvement in alpha or beta cell function in patients with long-duration diabetes., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)
- Published
- 2016
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37. Peculiar Magnetoelectric Coupling in BaTiO₃:Fe₁₁₃ ppm Nanoscopic Segregations.
- Author
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Amorim CO, Figueiras F, Amaral JS, Vaghefi PM, Tavares PB, Correia MR, Baghizadeh A, Alves E, Rocha J, and Amaral VS
- Abstract
We report polycrystalline BaTiO3 with cooperative magnetization behavior associated with the scarce presence of about 113 atomic ppm of Fe ions, clearly displaying magnetoelectric coupling with significant changes in magnetization (up to ΔM/M ≈ 32%) at the ferroelectric transitions. We find that Fe ions are segregated mostly at the interfaces between grain boundaries and an Fe-rich phase, forming a self-composite with high magnetoelectric coupling above room temperature. We compare our results with ab initio calculations and other experimental results found in the literature, proposing mechanisms that could be behind the magnetoelectric coupling within the ferroelectric matrix. These findings open the way for further strategies to optimize interfacial magnetoelectric couplings.
- Published
- 2015
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38. Photoluminescence studies of a perceived white light emission from a monolithic InGaN/GaN quantum well structure.
- Author
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Ben-Sedrine N, Esteves TC, Rodrigues J, Rino L, Correia MR, Sequeira MC, Neves AJ, Alves E, Bockowski M, Edwards PR, O'Donnell KP, Lorenz K, and Monteiro T
- Abstract
In this work we demonstrate by photoluminescence studies white light emission from a monolithic InGaN/GaN single quantum well structure grown by metal organic chemical vapour deposition. As-grown and thermally annealed samples at high temperature (1000 °C, 1100 °C and 1200 °C) and high pressure (1.1 GPa) were analysed by spectroscopic techniques, and the annealing effect on the photoluminescence is deeply explored. Under laser excitation of 3.8 eV at room temperature, the as-grown structure exhibits two main emission bands: a yellow band peaked at 2.14 eV and a blue band peaked at 2.8 eV resulting in white light perception. Interestingly, the stability of the white light is preserved after annealing at the lowest temperature (1000 °C), but suppressed for higher temperatures due to a deterioration of the blue quantum well emission. Moreover, the control of the yellow/blue bands intensity ratio, responsible for the white colour coordinate temperatures, could be achieved after annealing at 1000 °C. The room temperature white emission is studied as a function of incident power density, and the correlated colour temperature values are found to be in the warm white range: 3260-4000 K.
- Published
- 2015
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39. Effect of N2 and H2 plasma treatments on band edge emission of ZnO microrods.
- Author
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Rodrigues J, Holz T, Allah RF, Gonzalez D, Ben T, Correia MR, Monteiro T, and Costa FM
- Abstract
ZnO microrods were grown by laser assisted flow deposition technique in order to study their luminescence behaviour in the near band edge spectral region. Transmission electron microscopy analysis put in evidence the high crystallinity degree and microrod's compositional homogeneity. Photoluminescence revealed a dominant 3.31 eV emission. The correlation between this emission and the presence of surface states was investigated by performing plasma treatments with hydrogen and nitrogen. The significant modifications in photoluminescence spectra after the plasma treatments suggest a connexion between the 3.31 eV luminescence and the surface related electronic levels.
- Published
- 2015
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40. Luminescence studies on green emitting InGaN/GaN MQWs implanted with nitrogen.
- Author
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Sousa MA, Esteves TC, Sedrine NB, Rodrigues J, Lourenço MB, Redondo-Cubero A, Alves E, O'Donnell KP, Bockowski M, Wetzel C, Correia MR, Lorenz K, and Monteiro T
- Abstract
We studied the optical properties of metalorganic chemical vapour deposited (MOCVD) InGaN/GaN multiple quantum wells (MQW) subjected to nitrogen (N) implantation and post-growth annealing treatments. The optical characterization was carried out by means of temperature and excitation density-dependent steady state photoluminescence (PL) spectroscopy, supplemented by room temperature PL excitation (PLE) and PL lifetime (PLL) measurements. The as-grown and as-implanted samples were found to exhibit a single green emission band attributed to localized excitons in the QW, although the N implantation leads to a strong reduction of the PL intensity. The green band was found to be surprisingly stable on annealing up to 1400°C. A broad blue band dominates the low temperature PL after thermal annealing in both samples. This band is more intense for the implanted sample, suggesting that defects generated by N implantation, likely related to the diffusion/segregation of indium (In), have been optically activated by the thermal treatment.
- Published
- 2015
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41. Left ventricular diastolic function in patients with type 2 diabetes treated with a dipeptidyl peptidase-4 inhibitor- a pilot study.
- Author
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Nogueira KC, Furtado M, Fukui RT, Correia MR, Dos Santos RF, Andrade JL, and Rossi da Silva ME
- Abstract
Background: Blood glucose control is fundamental albeit not enough to prevent diabetic macrovascular complications. Dipeptidyl peptidase-4 (DPP-4) inhibitors are effective in improving metabolic parameters in patients with type 2 diabetes mellitus (T2DM) but little is known about its cardiovascular effects. We compared the DPP-4 inhibitor sitagliptin with bedtime NPH insulin (NPH) as add-on therapy in patients with T2DM, aiming to ascertain which drug would have additional cardioprotective effects., Methods: Thirty-five T2DM patients inadequately controlled with metformin plus glyburide were randomized to receive sitagliptin (n = 18) or NPH (n = 17) for 24 weeks. Fasting plasma glucose, HbA1c, lipid profile, C-reactive protein, active glucagon-like peptide (aGLP-1) levels, 24-hour ambulatory blood pressure measurement and comprehensive 2-dimensional echocardiogram were determined before and after treatments., Results: Both sitagliptin and NPH therapies decreased HbA1c levels after 24 weeks. Fasting plasma glucose and triglyceride levels decreased in the NPH group whereas only sitagliptin increased aGLP-1 levels. Left ventricular diastolic dysfunction (LVDD) was detected in 58.6% of twenty-nine patients evaluated. Beneficial effects in LVDD were observed in 75% and 11% of patients treated with sitagliptin and NPH, respectively (p = 0.015). Neither therapy changed C-reactive protein or blood pressure., Conclusions: Sitagliptin and bedtime NPH were similarly effective on glucose control. Improvement in LVDD in T2DM patients treated with sitagliptin was suggested, probably related to the increase of aGLP-1 levels. Therefore, DPP-4 inhibitor seems to have cardioprotective effects independent of glucose control and may have a role in the prevention of diabetic cardiomyopathy.
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- 2014
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42. The PTPN22 1858T allele but not variants in the proximal promoter region of IL-21 gene is associated with the susceptibility to type 1 diabetes and the presence of autoantibodies in a Brazilian cohort.
- Author
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Mainardi-Novo DT, Santos AS, Fukui RT, Gamberini M, Correia MR, Ruiz MO, Mangueira CL, Matioli SR, Vasconcelos DM, and Silva ME
- Subjects
- Alleles, Autoantibodies genetics, Autoantibodies metabolism, Biomarkers metabolism, Brazil, Case-Control Studies, Diabetes Mellitus, Type 1 immunology, Diabetes Mellitus, Type 1 pathology, Female, Gene Expression, Gene Frequency, Genetic Predisposition to Disease, Glutamate Decarboxylase genetics, Glutamate Decarboxylase immunology, HLA-DR3 Antigen genetics, HLA-DR3 Antigen immunology, HLA-DR4 Antigen genetics, HLA-DR4 Antigen immunology, Humans, Interleukins immunology, Male, Promoter Regions, Genetic, Protein Tyrosine Phosphatase, Non-Receptor Type 22 immunology, Risk, Sequence Analysis, DNA, White People, Autoantibodies immunology, Diabetes Mellitus, Type 1 genetics, Interleukins genetics, Protein Tyrosine Phosphatase, Non-Receptor Type 22 genetics
- Abstract
Interleukin (IL)-21 and protein tyrosine phosphatase non-receptor 22 (PTPN22) regulate lymphocyte function and have been implicated in the pathogenesis of autoimmune diabetes. We sequenced the proximal promoter of the IL-21 gene for the first time and analysed the PTPN22 1858T polymorphism in type 1A diabetes (T1AD) patients and healthy controls (HC). We correlated the frequencies of islet and extra-pancreatic autoantibodies with genotypes from both loci. The case series comprised 612 T1AD patients and 792 HC. Genotyping of PTPN22 C1858T was performed on 434 T1AD patients and 689 HC. The -448 to +83 base pairs (bp) region of the IL-21 gene was sequenced in 309 Brazilian T1AD and 189 HC subjects. We also evaluated human leucocyte antigen (HLA) DR3/DR4 alleles. The frequencies of glutamic acid decarboxylase (GAD65), tyrosine phosphatase-like protein (IA)-2, anti-nuclear antibody (ANA), thyroid peroxidase (TPO), thyroglobulin (TG), thyrotrophin receptor autoantibody (TRAb), anti-smooth muscle (ASM) and 21-hydroxylase (21-OH) autoantibodies were higher in T1AD patients than in HC. The PTPN22 1858T allele was associated with an increased risk for developing T1AD [odds ratio (OR) = 1·94; P < 0·001], particularly in patients of European ancestry, and with a higher frequency of GAD65 and TG autoantibodies. HLA-DR3/DR4 alleles predominated in T1AD patients. A heterozygous allelic IL-21 gene variant (g.-241 T > A) was found in only one patient. In conclusion, only PTPN22 C1858T polymorphism and HLA-DR3 and/or DR4 alleles, but not allelic variants in the 5'-proximal region of the IL-21 gene were associated with T1AD risk. Patients with T1AD had increased frequencies of anti-islet-cell, anti-thyroid, anti-nuclear, anti-smooth muscle and anti-21-OH autoantibodies. The C1858T PTPN22 polymorphism was also associated with a higher frequency of GAD65 and TG autoantibodies., (© 2012 British Society for Immunology.)
- Published
- 2013
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43. Cumulative Helicobacter pylori eradication therapy in obese patients undergoing gastric bypass surgery.
- Author
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Cerqueira RM, Correia MR, Fernandes CD, Vilar H, and Manso MC
- Subjects
- Adult, Aged, Amoxicillin administration & dosage, Anti-Bacterial Agents administration & dosage, Clarithromycin administration & dosage, Drug Resistance, Bacterial, Drug Therapy, Combination, Female, Gastric Bypass statistics & numerical data, Helicobacter Infections complications, Helicobacter Infections epidemiology, Helicobacter pylori drug effects, Humans, Levofloxacin, Male, Middle Aged, Obesity, Morbid complications, Obesity, Morbid epidemiology, Obesity, Morbid surgery, Ofloxacin administration & dosage, Portugal epidemiology, Practice Guidelines as Topic, Proton Pump Inhibitors administration & dosage, Risk Factors, Stomach Neoplasms epidemiology, Stomach Neoplasms etiology, Surgical Wound Infection epidemiology, Surgical Wound Infection etiology, Treatment Failure, Young Adult, Gastric Bypass adverse effects, Helicobacter Infections drug therapy, Helicobacter pylori pathogenicity, Obesity, Morbid drug therapy, Stomach Neoplasms prevention & control, Surgical Wound Infection drug therapy
- Abstract
Background: Our aim was to assess, in obese patients undergoing Roux-en Y gastric bypass surgery, the cumulative Helicobacter pylori (HP) eradication rates in two consecutive time spans (2006-2008 and 2009-2010)., Methods: The study adopted a 14-day clarithromycin-based triple therapy in first-line treatment as proposed by the Maastricht III consensus-proton pump inhibitor bid, clarithromycin 500 mg bid and amoxicillin 1,000 mg bid-and a 14-day second-line levofloxacin-based empirical regimen-proton pump inhibitor bid, amoxicillin 1,000 mg bid and levofloxacin 500 mg od., Results: In 2006-2008, 253 patients received first-line therapy. HP was eradicated in 200 patients and 14 patients withdrew (intention to treat (ITT) = 79.1 %; per protocol (PP) = 83.7 %). In the remaining 39 patients, HP was eradicated in 22 patients and 8 patients withdrew (ITT = 56.4 % and PP = 71.0 %). Thus, out of 253 patients, HP was eradicated in 222 patients, 22 patients withdrew and 9 remained positive. In 2009-2010, 437 patients received first-line therapy. HP was eradicated in 256 patients and 30 patients withdrew (ITT = 58.6 %; PP = 62.9 %). In the remaining 151 patients, HP was eradicated in 80 and 6 patients withdrew (ITT = 53.0 % and PP = 55.1 %). These results give cumulative eradication rates of 87.7 % ITT and 96.1 % PP (2006-2008) and of 76.9 % ITT and 83.8 % PP (2009-2010)., Conclusions: Cumulative HP eradication rates have fallen during 2006-2010 due to the fall of first-line eradication therapy rate, which was around 20 %. Therefore, the first-line clarithromycin-based Maastricht III consensus eradication is no longer effective in bariatric patients indicating the need to test new regimens.
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- 2013
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44. Potentiometric chemical sensors from lignin-poly(propylene oxide) copolymers doped by carbon nanotubes.
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Rudnitskaya A, Evtuguin DV, Costa LC, Graça MP, Fernandes AJ, Correia MR, Gomes MT, and Oliveira JA
- Abstract
Hardwood and softwood lignins obtained from industrial sulphite and kraft and laboratory oxygen-organosolv pulping processes were employed in co-polymerization with tolylene 2,4-diisocyanate terminated poly(propylene glycol). The obtained lignin-based polyurethanes were doped with 0.72 w/w% of multiwall carbon nanotubes (MWCNTs) with the aim of increasing their electrical conductivity to the levels suitable for sensor applications. Effects of the polymer doping with MWCNTs were assessed using electrical impedance (EIS) and UV-Resonance Raman (UV-RR) spectroscopy. Potentiometric sensors were prepared by drop casting of liquid polymer on the surface of carbon glass or platinum electrodes. Lignin-based sensors displayed a very low or no sensitivity to all alkali, alkali-earth and transition metal cations ions except Cr(VI) at pH 2. Response to Cr(VI) values of 39, 50 and 53 mV pX(-1) for the sensors based on kraft, organosolv and lignosulphonate lignins, respectively, were observed. Redox sensitivity values close to the theoretical values of 20 and 21 mV pX(-1) for organosolv and lignosulphonate based sensors respectively were detected in the Cr(III)/Cr(VI) solutions while a very low response was observed in the solutions containing Fe(CN)(6)(3-/4-). Conducting composite lignin-based polyurethanes doped with MWCNTs were suggested as being promising materials for Cr(VI)-sensitive potentiometric sensors.
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- 2013
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45. Autoantibodies and high-risk HLA susceptibility markers in first-degree relatives of Brazilian patients with type 1 diabetes mellitus: a progression to disease based study.
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Alves LI, Davini E, Correia MR, Fukui RT, Santos RF, Cunha MR, Rocha DM, Volpini WM, and Silva ME
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- Adolescent, Adult, Age Factors, Aged, Autoantibodies immunology, Biomarkers blood, Brazil, Child, Child, Preschool, Disease Progression, Family, Female, Genetic Predisposition to Disease, Genotype, Glutamate Decarboxylase immunology, HLA-DQ Antigens immunology, HLA-DR Antigens immunology, Humans, Infant, Insulin immunology, Male, Middle Aged, Receptor-Like Protein Tyrosine Phosphatases, Class 8 immunology, Sex Factors, Young Adult, Autoantibodies blood, Diabetes Mellitus, Type 1 genetics, Diabetes Mellitus, Type 1 immunology
- Abstract
Purpose: The objective of this study was to determine the frequencies of autoantibodies to heterogeneous islet-cell cytoplasmic antigens (ICA), glutamic acid decarboxylase(65) (GAD(65)A), insulinoma-associated antigen-2 (IA-2A) and insulin (IAA)-and human leukocyte antigen (HLA) class II markers (HLA-DR and -DQ) in first degree relatives of heterogeneous Brazilian patients with type I diabetes (T1DM). A major focus of this study was to determine the influence of age, gender, proband characteristics and ancestry on the prevalence of autoantibodies and HLA-DR and -DQ alleles on disease progression and genetic predisposition to T1DM among the first-degree relatives., Methods: IAA, ICA, GAD(65)A, IA-2A and HLA- class II alleles were determined in 546 first-degree-relatives, 244 siblings, 55 offspring and 233 parents of 178 Brazilian patients with T1DM., Results: Overall, 8.9% of the relatives were positive for one or more autoantibodies. IAA was the only antibody detected in parents. GAD(65) was the most prevalent antibody in offspring and siblings as compared to parents and it was the sole antibody detected in offspring. Five siblings were positive for the IA-2 antibody. A significant number (62.1%) of siblings had 1 or 2 high risk HLA haplotypes. During a 4-year follow-up study, 5 siblings (expressing HLA-DR3 or -DR4 alleles) and 1 offspring positive for GAD(65)A progressed to diabetes., Conclusions: The data indicated that the GAD(65) and IA-2 antibodies were the strongest predictors of T1DM in our study population. The high risk HLA haplotypes alone were not predictive of progression to overt diabetes.
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- 2012
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46. Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus.
- Author
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Machado HA, Vieira M, Cunha MR, Correia MR, Fukui RT, Santos RF, Rocha DM, Wajchenberg BL, Lage SG, and Silva ME
- Subjects
- Blood Glucose metabolism, Carotid Arteries pathology, Diabetes Mellitus, Type 2 blood, Fasting blood, Female, Humans, Hypoglycemic Agents therapeutic use, Lipids blood, Male, Middle Aged, Organ Size drug effects, Prospective Studies, Carotid Arteries drug effects, Diabetes Mellitus, Type 2 drug therapy, Hypoglycemic Agents pharmacology, Metformin pharmacology, Sulfonylurea Compounds pharmacology
- Abstract
Objective: To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes., Methods: A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA1 levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter., Results: Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery., Conclusions: Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.
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- 2012
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47. Risk factors for in-hospital mortality in cirrhotic patients with oesophageal variceal bleeding.
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Cerqueira RM, Andrade L, Correia MR, Fernandes CD, and Manso MC
- Subjects
- Adult, Aged, Aged, 80 and over, Erythrocyte Transfusion, Esophageal and Gastric Varices drug therapy, Female, Gastrointestinal Agents therapeutic use, Gastrointestinal Hemorrhage drug therapy, Hospital Mortality, Hospitalization, Humans, Lypressin analogs & derivatives, Lypressin therapeutic use, Male, Middle Aged, Octreotide therapeutic use, Platelet Count, Portugal epidemiology, Risk Factors, Severity of Illness Index, Terlipressin, Vasoconstrictor Agents therapeutic use, Esophageal and Gastric Varices mortality, Gastrointestinal Hemorrhage mortality, Liver Cirrhosis mortality
- Abstract
Introduction: Oesophageal variceal bleeding (OVB) is a high mortality rate complication in patients with cirrhosis. The aim of this study was to assess the risk factors for in-hospital mortality (IHM) in cirrhotic patients with OVB., Patients and Methods: The study cohort included 102 patients (average age, 55.4 ± 12.6 years, 71.6% men) consecutively admitted to our hospital with OVB. All the patients underwent upper endoscopy within 12 h and octeotride or terlipressin therapy was started at admission and continued for 5 days. To calculate Model for End-Stage Liver Disease (MELD) and Child-Turcotte-Pugh scores, laboratory test data from blood samples taken within 6 h of admission were used., Results: The IHM was 18.6% [19 patients; confidence interval (95% CI): 11.1-26.2%]. In the univariate analysis, transfusion with 2 or more units of packed red blood cells [PRBC; P=0.038; odds ratio (OR)=7.8; 95% CI: 1.2-61.3], platelets of 100/ml or less (P=0.014; OR=3.6; 95% CI: 1.2-10.3), Child-Turcotte-Pugh score of 10 or more (P=0.002; OR=4.0; 95% CI: 1.2-13.2) and MELD of 18 or more (P=0.044; OR=2.8; 95% CI: 1.1-8.1) were associated with IHM. In the multivariate analysis, transfusion with 2 or more units of PRBC (P=0.076; OR=6.7; 95% CI: 0.82-54.8), platelets of 100/ml or less (P=0.031; OR=3.4; 95% CI: 1.1-10.6) and MELD of 18 or more (P=0.048; OR=3.2; 95% CI: 1.02-10.1) remained independently associated with IHM. Applying a receiver operating characteristic analysis, the area under the curve derived from the multivariate analysis model was 0.76 (95% CI: 0.64-0.88) for IHM., Conclusion: Cirrhotic patients with OVB and MELD of 18 or more, platelets of 100/ml or less and requiring transfusion of 2 or more units of PRBC were at an increased risk of IHM. Overall, the logistic regression model correctly predicts 82.2% of IHM patients.
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- 2012
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48. Large-area high-throughput synthesis of monolayer graphene sheet by Hot Filament Thermal Chemical Vapor Deposition.
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Hawaldar R, Merino P, Correia MR, Bdikin I, Grácio J, Méndez J, Martín-Gago JA, and Singh MK
- Abstract
We report hot filament thermal CVD (HFTCVD) as a new hybrid of hot filament and thermal CVD and demonstrate its feasibility by producing high quality large area strictly monolayer graphene films on Cu substrates. Gradient in gas composition and flow rate that arises due to smart placement of the substrate inside the Ta filament wound alumina tube accompanied by radical formation on Ta due to precracking coupled with substrate mediated physicochemical processes like diffusion, polymerization etc., led to graphene growth. We further confirmed our mechanistic hypothesis by depositing graphene on Ni and SiO(2)/Si substrates. HFTCVD can be further extended to dope graphene with various heteroatoms (H, N, and B, etc.,), combine with functional materials (diamond, carbon nanotubes etc.,) and can be extended to all other materials (Si, SiO(2), SiC etc.,) and processes (initiator polymerization, TFT processing) possible by HFCVD and thermal CVD.
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- 2012
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49. Helicobacter pylori eradication therapy in obese patients undergoing gastric bypass surgery--fourteen days superior to seven days?
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Cerqueira RM, Manso MC, Correia MR, Fernandes CD, Vilar H, Nora M, and Martins P
- Subjects
- Adult, Amoxicillin administration & dosage, Amoxicillin therapeutic use, Anti-Bacterial Agents therapeutic use, Clarithromycin therapeutic use, Drug Administration Schedule, Drug Therapy, Combination, Female, Helicobacter Infections complications, Humans, Male, Middle Aged, Obesity, Morbid complications, Proton Pump Inhibitors therapeutic use, Retrospective Studies, Anti-Bacterial Agents administration & dosage, Clarithromycin administration & dosage, Gastric Bypass, Helicobacter Infections drug therapy, Helicobacter pylori, Obesity, Morbid surgery, Proton Pump Inhibitors administration & dosage
- Abstract
Background: The high prevalence of Helicobacter pylori (HP) in our obese population undergoing Roux-en-Y bypass gastric surgery (69.4%) and the concern that it may exacerbate postoperative foregut symptoms and increase gastric cancer risk led us to adopt a policy of HP systematic eradication in this group of patients. Our aim, in obese patients undergoing bypass gastric surgery, was to compare effectivity of 7- and 14-days clarithromycin-based triple therapy as the first-line treatment for HP eradication., Methods: Three hundred seventy-three patients [mean age 41.2 ± 10.3 years; 313 women (83.9%)] were HP positive determined by histology or urea breath test. In 2005, 94 patients (Group A) were treated with a 7-days triple therapy-proton pump inhibitor (PPI) b.i.d., clarithromycin (CL) 500 mg b.i.d., and amoxicillin (AMX) 1,000 mg b.i.d. Since 2006, 279 patients (Group B) were treated with a similar 14-days drug regimen-PPI b.i.d., CL 500 mg b.i.d., and AMX 1,000 mg b.i.d. Posttreatment HP status was assessed by C13 urea breath test 4-6 weeks after the end of therapy., Results: The eradication rates were 67.0% (Group A) and 79.9% (Group B). The eradication rate achieved with 14-days triple therapy was significantly higher than with 7-days triple therapy (OR = 1.96; 95% CI: 1.16-3.30; p = 0.016)., Conclusions: A 14-days triple therapy is more effective than 7-days triple therapy suggesting this regimen should be the first-line therapy for HP eradication in Portuguese obese patients undergoing bypass gastric surgery.
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- 2011
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50. Chemisorption of phosphoric acid and surface characterization of As passivated AlN powder against hydrolysis.
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Ganesh I, Olhero SM, Araújo AB, Correia MR, Sundararajan G, and Ferreira JM
- Abstract
By simply refluxing a commercial AlN powder in a mixture solution of ethanol, H(3)PO(4), and Al(H(2)PO(4))(3) for 24 h at 80 degrees C, the powder was successfully passivated against hydrolysis. The phosphate layer formed on the surface of AlN powder was found to be quite stable toward protecting the powder from hydrolysis. The efficacy of the coating was established by suspending the treated and the untreated powders in water for 72 h and subsequently characterizing them by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Raman analysis. The good dispersing behavior of the treated AlN powder in water was confirmed by the low viscosity of an AlN suspension containing 50 vol % solids demonstrating the viability of replacing organic solvents by water in colloidal processing of AlN-based ceramics.
- Published
- 2008
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