Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 185
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Nature ; 627(8002): 67-72, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38448698

RESUMO

Ordinary metals contain electron liquids within well-defined 'Fermi' surfaces at which the electrons behave as if they were non-interacting. In the absence of transitions to entirely new phases such as insulators or superconductors, interactions between electrons induce scattering that is quadratic in the deviation of the binding energy from the Fermi level. A long-standing puzzle is that certain materials do not fit this 'Fermi liquid' description. A common feature is strong interactions between electrons relative to their kinetic energies. One route to this regime is special lattices to reduce the electron kinetic energies. Twisted bilayer graphene1-4 is an example, and trihexagonal tiling lattices (triangular 'kagome'), with all corner sites removed on a 2 × 2 superlattice, can also host narrow electron bands5 for which interaction effects would be enhanced. Here we describe spectroscopy revealing non-Fermi-liquid behaviour for the ferromagnetic kagome metal Fe3Sn2 (ref. 6). We discover three C3-symmetric electron pockets at the Brillouin zone centre, two of which are expected from density functional theory. The third and most sharply defined band emerges at low temperatures and binding energies by means of fractionalization of one of the other two, most likely on the account of enhanced electron-electron interactions owing to a flat band predicted to lie just above the Fermi level. Our discovery opens the topic of how such many-body physics involving flat bands7,8 could differ depending on whether they arise from lattice geometry or from strongly localized atomic orbitals9,10.

2.
Nature ; 565(7738): 209-212, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30602792

RESUMO

The Einstein-de Haas effect was originally observed in a landmark experiment1 demonstrating that the angular momentum associated with aligned electron spins in a ferromagnet can be converted to mechanical angular momentum by reversing the direction of magnetization using an external magnetic field. A related problem concerns the timescale of this angular momentum transfer. Experiments have established that intense photoexcitation in several metallic ferromagnets leads to a drop in magnetization on a timescale shorter than 100 femtoseconds-a phenomenon called ultrafast demagnetization2-4. Although the microscopic mechanism for this process has been hotly debated, the key question of where the angular momentum goes on these femtosecond timescales remains unanswered. Here we use femtosecond time-resolved X-ray diffraction to show that most of the angular momentum lost from the spin system upon laser-induced demagnetization of ferromagnetic iron is transferred to the lattice on sub-picosecond timescales, launching a transverse strain wave that propagates from the surface into the bulk. By fitting a simple model of the X-ray data to simulations and optical data, we estimate that the angular momentum transfer occurs on a timescale of 200 femtoseconds and corresponds to 80 per cent of the angular momentum that is lost from the spin system. Our results show that interaction with the lattice has an essential role in the process of ultrafast demagnetization in this system.

3.
BMC Microbiol ; 24(1): 187, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38802760

RESUMO

BACKGROUND: Rapid antimicrobial susceptibility testing (AST) is urgently needed to provide safer treatment to counteract antimicrobial resistance. This is critical in septic patients, because resistance increases empiric therapy uncertainty and the risk of a poor outcome. We validate a novel 2h flow cytometry AST assay directly from positive blood cultures (PBC) by using a room temperature stable FASTgramneg and FASTgrampos kits (FASTinov® Porto, Portugal) in three sites: FASTinov (site-1), Hospital Ramon y Cajal, Madrid, Spain (site-2) and Centro Hospitalar S. João, Porto, Portugal (site-3). A total of 670 PBC were included: 333 spiked (site-1) and 337 clinical PBC (151 site-2 and 186 site-3): 367 gram-negative and 303 gram-positive. Manufacturer instructions were followed for sample preparation, panel inoculation, incubation (1h/37ºC) and flow cytometry analysis using CytoFlex (Site-1 and -2) or DxFlex (site-3) both instruments from Beckman-Coulter, USA. RESULTS: A proprietary software (bioFAST) was used to immediately generate a susceptibility report in less than 2 h. In parallel, samples were processed according to reference AST methods (disk diffusion and/or microdilution) and interpreted with EUCAST and CLSI criteria. Additionally, ten samples were spiked in all sites for inter-laboratory reproducibility. Sensitivity and specificity were >95% for all antimicrobials. Reproducibility was 96.8%/95.0% for FASTgramneg and 95.1%/95.1% for FASTgrampos regarding EUCAST/CLSI criteria, respectively. CONCLUSION: FASTinov® kits consistently provide ultra-rapid AST in 2h with high accuracy and reproducibility on both Gram-negative and Gram-positive bacteria. This technology creates a new paradigm in bacterial infection management and holds the potential to significantly impact septic patient outcomes and antimicrobial stewardship.


Assuntos
Antibacterianos , Hemocultura , Citometria de Fluxo , Testes de Sensibilidade Microbiana , Humanos , Citometria de Fluxo/métodos , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana/métodos , Testes de Sensibilidade Microbiana/instrumentação , Hemocultura/métodos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/isolamento & purificação , Fatores de Tempo , Portugal , Espanha , Reprodutibilidade dos Testes
4.
Reumatismo ; 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39315559

RESUMO

This case series aims to characterize the development of systemic lupus erythematosus (SLE) induced by anti-tumor necrosis factor α (anti-TNFα) therapy in patients with inflammatory rheumatic diseases, namely rheumatoid arthritis (RA), spondylarthritis (SpA), and psoriatic arthritis (PsA). Patients with a diagnosis of SLE induced by anti-TNFα therapy and registered on the Rheumatic Diseases Portuguese Register (Reuma.pt) who started their first anti-TNFα between 2001 and 2020 were included. Demographic, clinical, and laboratory data were obtained by consulting Reuma.pt. The diagnosis of SLE induced by anti-TNFα was considered if there was a temporal relationship between the onset of anti-TNFα therapy and manifestations (clinical and immunological) in accordance with the American College of Rheumatology/European League Against Rheumatism criteria (2019). A total of 607 patients with inflammatory rheumatic diseases and six cases of SLE induced by anti-TNF-α therapy were reviewed: two patients were affected by RA, three patients by SpA, and one by PsA. All these patients had articular and constitutional symptoms that improved after discontinuation of the anti-TNFα agent. After switching to a second anti-TNFα agent, there was no recurrence of SLE over time. The development of SLE secondary to anti-TNFα agents in inflammatory rheumatic patients is rare. In this case series, all patients had a mild disease that improved after therapy discontinuation without recurrence of the disease. SLE induced by anti-TNFα should be considered in the follow-up of RA, SpA, and PsA patients.

5.
Reumatismo ; 76(1)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38523579

RESUMO

Spontaneous subcapsular and perirenal hemorrhage, known as Wunderlich syndrome (WS), is a rare clinical manifestation of polyarteritis nodosa (PAN). We report a case of a 48-year-old male with a history of recurrent episodes of leg muscle tenderness and dysesthesia, bilateral flank pain, painful nodular skin lesions in the lower limbs, weight loss, and difficult-to-control arterial hypertension. The abdominopelvic computed tomography angiography showed a large left perirenal hematoma, leading to the patient's admission to the intensive care unit. After the exclusion of infectious or neoplastic foci, the patient was diagnosed with PAN and started intravenous methylprednisolone pulses with a good response. Since WS is a rare initial clinical manifestation of PAN, an early diagnosis and aggressive treatment will significantly improve clinical outcomes.


Assuntos
Nefropatias , Poliarterite Nodosa , Masculino , Humanos , Pessoa de Meia-Idade , Poliarterite Nodosa/complicações , Poliarterite Nodosa/diagnóstico , Poliarterite Nodosa/terapia , Nefropatias/complicações , Nefropatias/terapia , Hemorragia/etiologia , Hematoma/complicações , Hematoma/terapia , Angiografia/efeitos adversos
6.
Public Health ; 216: 33-38, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36791648

RESUMO

OBJECTIVES: This study aimed to estimate five harmonized healthy aging indicators covering functional ability and intrinsic capacity among older women and men from Brazil and England and evaluate their association with loneliness. STUDY DESIGN: This was a cross-sectional study. METHODS: We used two nationally representative samples of men and women aged ≥60 years from the Brazilian Longitudinal Study of Aging (ELSI-Brazil) wave 2 (2019-2021; n = 6929) and the English Longitudinal Study of Aging wave 9 (2018-2019; n = 5902). Healthy aging included five separate indicators (getting dressed, taking medication, managing money, cognitive function, and handgrip strength). Loneliness was measured by the 3-item University of California Loneliness Scale. Logistic regression models stratified by sex and country were performed. RESULTS: Overall, age-adjusted healthy aging indicators were worse in Brazil compared with England for both men and women. Considering functional ability, loneliness was negatively associated with all indicators (ranging from odds ratio [OR] = 0.26, [95% confidence interval (CI) 0.13-0.52] in English men regarding the ability to take medication to OR = 0.49 [95% CI 0.27-0.89] in Brazilian women regarding the ability to manage money). Considering intrinsic capacity, loneliness was negatively associated with a higher cognitive function (OR = 0.72; 95% CI 0.55-0.95 in English women) and a higher handgrip strength (OR = 0.61; 95% CI 0.45-0.83 in Brazilian women). Lonely women demonstrated lower odds of a higher number of healthy aging indicators than men in both countries. CONCLUSIONS: Country-specific social environments should be targeted by public policies to decrease loneliness and promote healthy aging later in life.


Assuntos
Envelhecimento Saudável , Solidão , Humanos , Masculino , Feminino , Idoso , Solidão/psicologia , Estudos Longitudinais , Brasil , Estudos Transversais , Força da Mão , Caracteres Sexuais , Inglaterra
7.
Br Poult Sci ; 64(2): 224-230, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36259551

RESUMO

1. This study determined the antimicrobial resistance profile and the biofilm-forming ability of Salmonella enterica strains isolated from commercial broiler houses over a three-year period in southern Brazil.2. Of the 720 drag swabs analysed, 37 (5%) tested positive for non-typhoidal Salmonella spp. and S. Heidelberg was the most frequent serovar.3. Among the antimicrobial resistant strains (83.8%; 31/37), resistance was most common to tetracycline, ampicillin and nalidixic acid. Multidrug resistance was found in 65% (24/37) of the isolates, with a large proportion of multidrug resistant S. Heidelberg strains (81%; 13/16).4. In total, 65% (24/37) of the isolates showed the ability to produce biofilm and multiple antimicrobial resistance was negatively correlated with biofilm formation.5. Strains susceptible to all tested antimicrobials tended to form stronger biofilms than multidrug resistant ones. This suggested that Salmonella spp. with less antimicrobial resistance depend more on the protection provided by biofilm to survive in the farm environment.


Assuntos
Antibacterianos , Salmonella enterica , Animais , Antibacterianos/farmacologia , Sorogrupo , Fazendas , Brasil , Farmacorresistência Bacteriana , Farmacorresistência Bacteriana Múltipla , Galinhas , Salmonella , Biofilmes , Testes de Sensibilidade Microbiana/veterinária
8.
Int J Biometeorol ; 66(10): 2117-2131, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35994120

RESUMO

Natural mineral waters (NMWs) emerge from the earth as springs and their beneficial therapeutic effect has been empirically recognized in different countries. Portugal has diverse NMW resources that are sought for the relief of different afflictions including dermatological complications. However, there is a lack of scientific validation supporting this empiric knowledge. In this study, we aimed to screen the in vitro bioactivity of Portuguese NMWs with different chemical profiles, namely sulfurous/bicarbonate/sodic (SBS), bicarbonate/magnesium, sulfated/calcic, sulfurous/chlorinated/sodic, sulfurous/bicarbonate/fluoridated/sodic, and chlorinated/sodic, focusing on aging-related skin alterations. Mouse skin fibroblasts and macrophages were exposed to culture medium prepared in different NMWs. Cellular viability was evaluated by MTT assay and etoposide-induced senescence was analyzed through the beta-galactosidase staining kit. Wound healing was investigated by the scratch assay, and phototoxicity/photoprotection after UVA irradiation was evaluated using a neutral red solution. ROS production was quantified using the 2'7'-dichlorofluorescin diacetate dye, and the activity of superoxide dismutase (SOD) was analyzed by a commercial kit after lipopolysaccharide exposure. NMWs within the SBS profile demonstrated anti-senescence activity in skin fibroblasts, along with a variable effect on cellular viability. Among the tested NMWs, two decreased cellular senescence and preserved cell viability and were therefore selected for subsequent studies, together with a SBS NMW with therapeutic indications for dermatologic diseases. Overall, the selected NMW promoted wound healing in skin fibroblasts and activated SOD in macrophages, thus suggesting an anti-oxidant effect. None of the NMWs prevented phototoxicity after UV irradiation. Our results shed a light on the anti-aging potential of Portuguese NMW, supporting their putative application in cosmetic or medical products.


Assuntos
Águas Minerais , Envelhecimento da Pele , Animais , Antioxidantes/farmacologia , Bicarbonatos , Células Cultivadas , Etoposídeo/farmacologia , Lipopolissacarídeos/farmacologia , Magnésio , Camundongos , Vermelho Neutro/farmacologia , Portugal , Espécies Reativas de Oxigênio , Pele , Superóxido Dismutase , Raios Ultravioleta , beta-Galactosidase/farmacologia
9.
Phys Rev Lett ; 125(11): 117208, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32975965

RESUMO

We investigate spin dynamics of microstates in artificial spin ice (ASI) in Ni_{81}Fe_{19} nanomagnets arranged in an interconnected kagome lattice using microfocus Brillouin light scattering, broadband ferromagnetic resonance, magnetic force microscopy, x-ray photoemission electron microscopy, and simulations. We experimentally reconfigure microstates in ASI using a 2D vector field protocol and apply microwave-assisted switching to intentionally trigger reversal. Our work is key for the creation of avalanches inside the kagome ASI and reprogrammable magnonics based on ASIs.

11.
Colorectal Dis ; 21(8): 903-908, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30963654

RESUMO

AIM: Robotic techniques are being increasingly used in colorectal surgery. There is, however, a lack of training opportunities and structured training programmes. Robotic surgery has specific problems and challenges for trainers and trainees. Ergonomics, specific skills and user-machine interfaces are different from those in traditional laparoscopic surgery. The aim of this study was to establish expert consensus on the requirements for a robotic train-the-trainer curriculum amongst robotic surgeons and trainers. METHOD: This is a modified Delphi-type study involving 14 experts in robotic surgery teaching. A reiterating 19-item questionnaire was sent out to the same group and agreement levels analysed. A consensus of 0.8 or higher was considered to be high-level agreement. RESULTS: Response rates were 93-100% and most items reached high levels of agreement within three rounds. Specific requirements for a robotic faculty development curriculum included maximizing dual-console teaching, theatre team training, nontechnical skills training, patient safety, user-machine interface training and telementoring. CONCLUSION: A clear need for the development of a train-the-trainer curriculum has been identified. Further research is needed to assess feasibility, effectiveness and clinical impact of a robotic train-the-trainer curriculum.


Assuntos
Cirurgia Colorretal/educação , Currículo/normas , Procedimentos Cirúrgicos Robóticos/educação , Capacitação de Professores/normas , Adulto , Consenso , Técnica Delphi , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
12.
Ann Chir Plast Esthet ; 64(5-6): 432-439, 2019 Nov.
Artigo em Francês | MEDLINE | ID: mdl-31421925

RESUMO

Residual nasal deformity in patients with cleft palate remains the main demand of these patients. Performing primary nasal surgery has significantly improved the results. However, it is still often necessary to improve the nasal morphology. Respect of tissues during primary surgery is essential and allows easier secondary corrections. Anatomical reconstruction greatly facilitates the treatment of secondary deformities. Do not hesitate in case of major labionasales sequelae, to make revision, according to the rules of primary surgery, of the entire lip and nose.


Assuntos
Fissura Palatina/cirurgia , Reoperação , Rinoplastia , Adolescente , Criança , Feminino , Humanos , Lactente , Masculino , Rinoplastia/métodos
13.
Opt Express ; 26(9): 12242-12256, 2018 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-29716137

RESUMO

While the industrial implementation of extreme ultraviolet lithography for upcoming technology nodes is becoming ever more realistic, a number of challenges have yet to be overcome. Among them is the need for actinic mask inspection. We report on reflective-mode lensless imaging of a patterned multi-layer mask sample at extreme ultraviolet wavelength that provides a finely structured defect map of the sample under test. Here, we present the imaging results obtained using ptychography in reflection mode at 6° angle of incidence from the surface normal and 13.5 nm wavelength. Moreover, an extended version of the difference map algorithm is employed that substantially enhances the reconstruction quality by taking into account both long and short-term variations of the incident illumination.

14.
Ann Chir Plast Esthet ; 63(3): 197-204, 2018 Jun.
Artigo em Francês | MEDLINE | ID: mdl-29402544

RESUMO

BACKGROUND: Cross-linked hyaluronic acid-based fillers have gained rapid acceptance for treating facial wrinkles, deep tissue folds and sunken areas due to aging. This study evaluates, in addition to space-filling properties, their effects on softness and elasticity as a secondary effect, following injection of 3 commercially available cross-linked hyaluronic acid-based fillers (15mg/mL, 17,5mg/mL and 20mg/mL) in patients presenting with congenital or acquired facial malformations. PATIENTS ET METHODS: We started injecting gels of cross-linked hyaluronic acid-based fillers in those cases in 2013; we performed 46 sessions of injections in 32 patients, aged from 13-32. Clinical assessment was performed by the patient himself and by a plastic surgeon, 15 days after injections and 6-18 months later. RESULTS: Cross-linked hyaluronic acid-based fillers offered very subtle cosmetic results and supplemented surgery with a very high level of satisfaction of the patients. When injected in fibrosis, the first session enhanced softness and elasticity; the second session enhanced the volume. Cross-linked hyaluronic acid-based fillers fill sunken areas and better softness and elasticity of scar tissues. CONCLUSION: In addition to their well-understood space-filling function, as a secondary effect, the authors demonstrate that cross-linked hyaluronic acid-based fillers improve softness and elasticity of scarring tissues. Many experimental studies support our observations, showing that cross-linked hyaluronic acid stimulates the production of several extra-cellular matrix components, including dermal collagen and elastin.


Assuntos
Cicatriz/terapia , Técnicas Cosméticas , Preenchedores Dérmicos/administração & dosagem , Face/anormalidades , Ácido Hialurônico/administração & dosagem , Adolescente , Adulto , Anormalidades Congênitas/terapia , Feminino , Humanos , Injeções , Masculino , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
15.
J Synchrotron Radiat ; 24(Pt 5): 963-974, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28862618

RESUMO

EIGER is a single-photon-counting hybrid pixel detector developed at the Paul Scherrer Institut, Switzerland. It is designed for applications at synchrotron light sources with photon energies above 5 keV. Features of EIGER include a small pixel size (75 µm × 75 µm), a high frame rate (up to 23 kHz), a small dead-time between frames (down to 3 µs) and a dynamic range up to 32-bit. In this article, the use of EIGER as a detector for electrons in low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) is reported. It is demonstrated that, with only a minimal modification to the sensitive part of the detector, EIGER is able to detect electrons emitted or reflected by the sample and accelerated to 8-20 keV. The imaging capabilities are shown to be superior to the standard microchannel plate detector for these types of applications. This is due to the much higher signal-to-noise ratio, better homogeneity and improved dynamic range. In addition, the operation of the EIGER detector is not affected by radiation damage from electrons in the present energy range and guarantees more stable performance over time. To benchmark the detector capabilities, LEEM experiments are performed on selected surfaces and the magnetic and electronic properties of individual iron nanoparticles with sizes ranging from 8 to 22 nm are detected using the PEEM endstation at the Surface/Interface Microscopy (SIM) beamline of the Swiss Light Source.

16.
Ann Chir Plast Esthet ; 61(5): 543-559, 2016 Oct.
Artigo em Francês | MEDLINE | ID: mdl-27614719

RESUMO

Facial traumas are common in children but often unconsidered. Facial injury is responsible of impressive bleeding because of the rich vascularization of the face; this bleeding is often underestimated because of the immediate arterial vasoconstriction that is very strong for children. The blood volume is 80ml/kg for a newborn, with a total of 250ml, reaching 70ml/kg at one year of age. The evaluation must be rigorously performed due to the risk of a sudden decompensation. Regarding the wounds, the primary repair must be performed directly neat or optimal in case of damaged tissues. The rule is to keep maximum of the integrity and to limit debridement. Careful repair often requires general anesthesia, especially in young children, to facilitate a perfect joining of the edges and of the mucocutaneous lines. Losses of substance should be treated by directed cicatrization. Flaps are never performed in children as a first intention for reasons developed below. Given the elasticity of the facial skeleton, fractures require a brutal shock to occur, but the clinical signs can be misleading. For instance, too specific and sometimes ignored, fractures can show weakly symptomatic signs : the fractures of the condylar and the orbital floor, with their respective complication that are temporomandibular bone ankylosis and definitive diplopia. Possible children abuse should be suspected in case of different age lesions and discrepancies between the told story and types of injuries. Once the vital urgency is eliminated, the orbital emergency should be first considered in facial traumas within the ophthalmology specialty because wounds and contusions of the globe are often under-evaluated and threaten the vision. The second emergency is the orbital floor fracture in its 'trapdoor' type, specific to the child. Combined with a motionless eye and uncontrollable vomiting, this is the second true urgency because it involves the prognosis of the oculomotricity and requires emergency surgery. Finally, dental trauma should not be overlooked because of their functional and aesthetic consequences. Primary cicatrization is usually rapid but scars remain inflammatory during a long time. The risk of hypertrophy exists in case of contusions and lacerations associated with wounds but also during puberty and in some locations. Age interfere with the result because growth will either improve or worsen the initial result, depending on the location and mechanism. The secondary specialized and prolonged managing and monitoring is capital on the functional, aesthetic and psychological points of view.


Assuntos
Traumatismos Faciais/cirurgia , Criança , Maus-Tratos Infantis/diagnóstico , Diagnóstico por Imagem , Ossos Faciais/lesões , Ossos Faciais/cirurgia , Traumatismos Faciais/diagnóstico por imagem , Fraturas Ósseas/cirurgia , Humanos , Boca/lesões , Boca/cirurgia , Exame Físico , Traumatismos Dentários/terapia
17.
Med Microbiol Immunol ; 203(1): 25-33, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24013184

RESUMO

Candida invasive infections have increased in frequency during the last decades. Such infections are often associated to medical indwelling devices like central venous catheter. The recurrent nature and difficulties in the treatment of these infections are often related to biofilm formation. The objective of this study was to investigate the anti-biofilm activity of low-molecular weight chitosan hydrogel (LMWCH), a natural biopolymer obtained from the N-deacylation of crustacean chitin, upon clinical relevant Candida species. The in vitro ability of LMWCH to impair biofilm formation and to disorganize a preformed biofilm was tested in polystyrene microplates and quantified by the semi quantitative XTT assay and by the crystal violet assay. LMWCH in vivo efficacy as a coating for medical indwelling devices was evaluated for the first time for Candida parapsilosis, using a mouse subcutaneous foreign body model using polyurethane catheter segments. Scanning electron microscopy was used to access biofilm architecture after LMWCH treatment. We found that LMWCH efficiently impaired biofilm formation of all Candida species, also promoting biofilm disaggregation. Most importantly, LMWCH was able to significantly inhibit biofilm formation by C. parapsilosis in an in vivo catheter mouse model. SEM images showed biofilm collapsed cells compatible with membrane damage, suggesting that this could be one of the possible mechanisms underlying biofilm impairment. LMWCH revealed to be a promising compound for treatment of candidiasis or its prevention through medical device coating.


Assuntos
Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Candida/fisiologia , Quitosana/farmacologia , Hidrogel de Polietilenoglicol-Dimetacrilato , Animais , Candida/ultraestrutura , Candidíase/tratamento farmacológico , Candidíase/microbiologia , Quitosana/administração & dosagem , Quitosana/química , Feminino , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Camundongos , Testes de Sensibilidade Microbiana , Peso Molecular , Plâncton/efeitos dos fármacos
18.
Eur J Clin Microbiol Infect Dis ; 33(12): 2241-7, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25012821

RESUMO

This is the first Portuguese multicenter observational and descriptive study that provides insights on the species distribution and susceptibility profiles of yeast isolates from fungemia episodes. Ten district hospitals across Portugal contributed by collecting yeast isolates from blood cultures and answering questionnaires concerning patients' data during a 12-month period. Molecular identification of cryptic species of Candida parapsilosis and C. glabrata complex was performed. The susceptibility profile of each isolate, considering eight of the most often used antifungals, was determined. Both Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) protocols were applied. The incidence of 240 episodes of fungemia was 0.88/1,000 admissions. Fifteen different species were found, with C. albicans (40 %) being the most prevalent, followed by C. parapsilosis (23 %) and C. glabrata (13 %). Most isolates were recovered from patients admitted to surgical wards or intensive care units, with 57 % being males and 32 % aged between 41 and 60 years. For both the CLSI and EUCAST protocols, the overall susceptibility rates ranged from 74 to 97 % for echinocandins and from 84 to 98 % for azoles. Important resistance rate discrepancies between protocols were observed in C. albicans and C. glabrata for echinocandins and in C. parapsilosis and C. tropicalis for azoles. Death associated with fungemia occurred in 25 % of the cases, with more than half of C. glabrata infections being fatal. The great number of Candida non-albicans is noteworthy despite a relatively low antifungal resistance rate. Studies like this are essential in order to improve empirical treatment guidelines.


Assuntos
Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candida/isolamento & purificação , Candidemia/microbiologia , Adolescente , Adulto , Idoso , Candidemia/epidemiologia , Criança , Pré-Escolar , Farmacorresistência Fúngica , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Portugal/epidemiologia , Adulto Jovem
19.
Phys Chem Chem Phys ; 16(48): 26624-30, 2014 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-25255452

RESUMO

We present an in situ experimental investigation of the magnetic and electronic properties of individual iron nanoparticles with sizes ranging from 8 to 22 nm as a function of oxygen exposure (0-80 L), using X-ray photoemission electron microscopy. The X-ray absorption spectroscopy results show that, irrespective of size and magnetic state, the early stages of the Fe nanoparticle oxidation occur through the initial formation of a non-magnetic FeO-like layer, followed by a progressive transformation of the latter to Fe3O4. At 80 L, the metallic iron core and the outer Fe3O4 shell are separated by a thin FeO layer. Our data suggest that the outer Fe3O4 layer has either a magnetic order that significantly differs from the respective bulk or that the FeO-like layer is responsible for a magnetic decoupling between the Fe3O4 shell and the iron core. Moreover, we find that the recently observed blocked magnetic state in the pure metallic iron nanoparticles persists upon oxygen exposure, demonstrating that the enhanced magnetic energy barriers do not originate from the free surface of the nanoparticles.

20.
Poult Sci ; 93(11): 2887-92, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25172927

RESUMO

Conventional culturing methods enable the detection of Campylobacter in broiler flocks. However, laboratory culture of Campylobacter is laborious because of its fastidious behavior and the presence of competing nontarget bacteria. This study evaluated different protocols to isolate Campylobacter from broiler litter, feces, and cloacal and drag swabs. Samples taken from commercial Brazilian broiler flocks were directly streaked onto Preston agar (PA), Campy-Line agar (CLA), and modified charcoal cefoperazone deoxycholate agar (mCCDA) and also enriched in blood-free Bolton broth (bfBB) for 24 and 48 h followed by plating onto the different selective media. Higher numbers of Campylobacter-positive cloacal and drag swab samples were observed using either direct plating or enrichment for 24 h before plating onto PA, compared with enrichment for 48 h (P < 0.05). Furthermore, direct plating was a more sensitive method to detect Campylobacter in broiler litter and feces samples. Analysis of directly plated samples revealed that higher Campylobacter levels were detected in feces streaked onto PA (88.8%), cloacal swabs plated onto mCCDA (72.2%), drag swabs streaked onto CLA or mCCDA (69.4%), and litter samples inoculated onto PA (63.8%). Preston agar was the best agar to isolate Campylobacter from directly plated litter samples (P < 0.05), but there was no difference in the efficacies of PA, mCCDA, and CLA in detecting Campylobacter in other samples. The isolated Campylobacter strains were phenotypically identified as Campylobacter jejuni or Campylobacter coli. The predominant contaminant observed in the Campylobacter cultures was Proteus mirabilis, which was resistant to the majority of antimicrobial agents in selective media. Together, these data showed that direct plating onto PA and onto either CLA or mCCDA as the second selective agar enabled the reliable isolation of thermophilic Campylobacter species from broiler samples. Finally, Campylobacter was detected in all broiler flocks sampled.


Assuntos
Técnicas Bacteriológicas/veterinária , Infecções por Campylobacter/veterinária , Campylobacter/isolamento & purificação , Galinhas , Doenças das Aves Domésticas/microbiologia , Ágar/análise , Animais , Infecções por Campylobacter/microbiologia , Cloaca/microbiologia , Fezes/microbiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA