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1.
Phys Rev Lett ; 127(20): 207001, 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34860055

RESUMO

At the interface between a ferromagnetic insulator and a superconductor there is a coupling between the spins of the two materials. We show that when a supercurrent carried by triplet Cooper pairs flows through the superconductor, the coupling induces a magnon spin current in the adjacent ferromagnetic insulator. The effect is dominated by Cooper pairs polarized in the same direction as the ferromagnetic insulator, so that charge and spin supercurrents produce similar results. Our findings demonstrate a way of converting Cooper pair supercurrents to magnon spin currents.

2.
Phys Rev Lett ; 127(26): 267001, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35029472

RESUMO

Unconventional superconductors are of high interest due to their rich physics, a topical example being topological edge states associated with p-wave superconductivity. A practical obstacle in studying such systems is the very low critical temperature T_{c} that is required to realize a p-wave superconducting phase in a material. We predict that the T_{c} of an intrinsic p-wave superconductor can be significantly enhanced by coupling to a conventional s-wave or d-wave superconductor with a higher critical temperature via an atomically thin ferromagnetic (F) layer. We show that this T_{c} boost is tunable via the direction of the magnetization in F. Moreover, we show that the enhancement in T_{c} can also be achieved using the Zeeman effect of an external magnetic field. Our findings provide a way to increase T_{c} in p-wave superconductors in a controllable way and make the exotic physics associated with such materials more easily accessible experimentally.

3.
Eur J Nucl Med Mol Imaging ; 48(6): 1976-1986, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33415433

RESUMO

PURPOSE: To evaluate PET/MR lung nodule detection compared to PET/CT or CT, to determine growth of nodules missed by PET/MR, and to investigate the impact of missed nodules on clinical management in primary abdominal malignancies. METHODS: This retrospective IRB-approved study included [18F]-FDG PET/MR in 126 patients. All had standard of care chest imaging (SCI) with diagnostic chest CT or PET/CT within 6 weeks of PET/MR that served as standard of reference. Two radiologists assessed lung nodules (size, location, consistency, position, and [18F]-FDG avidity) on SCI and PET/MR. A side-by-side analysis of nodules on SCI and PET/MR was performed. The nodules missed on PET/MR were assessed on follow-up SCI to ascertain their growth (≥ 2 mm); their impact on management was also investigated. RESULTS: A total of 505 nodules (mean 4 mm, range 1-23 mm) were detected by SCI in 89/126 patients (66M:60F, mean age 60 years). PET/MR detected 61 nodules for a sensitivity of 28.1% for patient and 12.1% for nodule, with higher sensitivity for > 7 mm nodules (< 30% and > 70% respectively, p < 0.05). 75/337 (22.3%) of the nodules missed on PET/MR (follow-up mean 736 days) demonstrated growth. In patients positive for nodules at SCI and negative at PET/MR, missed nodules did not influence patients' management. CONCLUSIONS: Sensitivity of lung nodule detection on PET/MR is affected by nodule size and is lower than SCI. 22.3% of missed nodules increased on follow-up likely representing metastases. Although this did not impact clinical management in study group with primary abdominal malignancy, largely composed of extra-thoracic advanced stage cancers, with possible different implications in patients without extra-thoracic spread.


Assuntos
Neoplasias Abdominais , Neoplasias Pulmonares , Neoplasias Abdominais/diagnóstico por imagem , Fluordesoxiglucose F18 , Humanos , Pulmão , Neoplasias Pulmonares/diagnóstico por imagem , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Estudos Retrospectivos , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X
4.
Prog Urol ; 31(10): 557-575, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34154957

RESUMO

INTRODUCTION: No recent national guidelines exist regarding the management of urinary tract infections (UTIs) in the presence of ureteral stent. This situation could lead to discrepancies in clinical management and less opportunity for a favorable patient's outcome. METHODS: All available data published on Medline® between 1998 and 2018 were systematically searched and reviewed. All papers assessing adult patients carrying ureteral stent were included for analysis. After studies critical analysis, national guidelines for clinical management were elaborated in order to answer clinical questions. RESULTS: A total of 451 articles were identified, of which 58 have been included. The prevalence of urinary tract infections in the presence of ureteral stent remains unknown. After 3 months, all endo-ureteral devices were colonized on microbiological study. These patients also presented a positive urine culture in 25 to 70% of the cases, often polymicrobial. Staphylococci, E. coli, Klebsiella, Pseudomonas, Enterococcus and Candida were the commonest micro-organisms responsible for urinary colonization or infection. The risk of UTI on endo-ureteral devices seemed higher the longer it stayed implanted. There is no justification in the literature to recommend a systematic change of endo-ureteral devices following a urinary tract infection. DISCUSSION: The existing literature is rich but of poor methodological quality, and therefore does not allow to draw robust conclusions. The greatest difficulty faced in this work was to accurately differentiate urinary colonizations from true infections, including clinical symptoms and not only microbiological results. CONCLUSION: These guidelines propose a standardized management of such common clinical situations. Well-designed studies are needed to upgrade the level of evidence of these guidelines.


Assuntos
Doenças Transmissíveis , Ureter , Infecções Urinárias , Adulto , Escherichia coli , Humanos , Stents , Infecções Urinárias/diagnóstico , Infecções Urinárias/epidemiologia , Infecções Urinárias/etiologia
5.
Phys Rev Lett ; 125(10): 107002, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32955310

RESUMO

We consider a hybrid structure where a material with Rashba-like spin-orbit coupling is proximity coupled to a conventional superconductor. We find that the superconducting critical temperature T_{c} can be tuned by rotating the vector n characterizing the axis of broken inversion symmetry. This is explained by a leakage of s-wave singlet Cooper pairs out of the superconducting region, and by conversion of s-wave singlets into other types of correlations, among these s-wave odd-frequency pairs robust to impurity scattering. These results demonstrate a conceptually different way of tuning T_{c} compared to the previously studied variation of T_{c} in magnetic hybrids.

6.
Eur J Nucl Med Mol Imaging ; 47(8): 1871-1884, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31705172

RESUMO

PURPOSE: Intrahepatic cholangiocarcinoma (ICC) is associated with a poor prognosis with surgical resection offering the best chance for long-term survival and potential cure. However, in up to 36% of patients who undergo surgery, more extensive disease is found at time of operation requiring cancellation of surgery. PET/MR is a novel hybrid technology that might improve local and whole-body staging in ICC patients, potentially influencing clinical management. This study was aimed to investigate the possible management implications of PET/MR, relative to conventional imaging, in patients affected by untreated intrahepatic cholangiocarcinoma. METHODS: Retrospective review of the clinicopathologic features of 37 patients with iCCC, who underwent PET/MR between September 2015 and August 2018, was performed to investigate the management implications that PET/MR had exerted on the affected patients, relative to conventional imaging. RESULTS: Of the 37 patients enrolled, median age 63.5 years, 20 (54%) were female. The same day PET/CT was performed in 26 patients. All patients were iCCC-treatment-naïve. Conventional imaging obtained as part of routine clinical care demonstrated early-stage resectable disease for 15 patients and advanced stage disease beyond the scope of surgical resection for 22. PET/MR modified the clinical management of 11/37 (29.7%) patients: for 5 patients (13.5%), the operation was cancelled due to identification of additional disease, while 4 "inoperable" patients (10.8%) underwent an operation. An additional 2 patients (5.4%) had a significant change in their operative plan based on PET/MR. CONCLUSIONS: When compared with standard imaging, PET/MR significantly influenced the treatment plan in 29.7% of patients with iCCC. TRIAL REGISTRATION: 2018P001334.


Assuntos
Neoplasias dos Ductos Biliares , Colangiocarcinoma , Neoplasias dos Ductos Biliares/diagnóstico por imagem , Neoplasias dos Ductos Biliares/patologia , Neoplasias dos Ductos Biliares/cirurgia , Colangiocarcinoma/diagnóstico por imagem , Colangiocarcinoma/patologia , Feminino , Fluordesoxiglucose F18 , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Estudos Retrospectivos
7.
Gynecol Endocrinol ; 36(9): 829-834, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32063091

RESUMO

Oocyte maturation defect is a challenging situation in the management of infertility, the etiology may be related to endocrine causes, protocols used in ovarian stimulation, oocyte intrinsic defects or procedures in embryology laboratory. We report three Mexican females in treatment for primary infertility with non-mature oocytes after ovary stimulation and oocyte capture in whom a genetic diagnosis of TUBB8-oocyte maturation defect was revealed by exome sequencing. Two couples achieved pregnancies though oocyte donation after establishing the genetic etiology. Our results expand the role of TUBB8-disorders in patients of non-Asian ethnicity. Oocyte maturation defects of monogenic origin are a growing group of disorders that endocrinologists and reproductive medicine specialists should be aware in order to provide referral to genetics for establish a correct and opportune diagnosis.


Assuntos
Doenças Genéticas Inatas/terapia , Infertilidade Feminina/diagnóstico , Infertilidade Feminina/terapia , Oogênese/genética , Tubulina (Proteína)/genética , Adulto , Análise Mutacional de DNA , Feminino , Doenças Genéticas Inatas/diagnóstico , Doenças Genéticas Inatas/epidemiologia , Humanos , Infertilidade Feminina/epidemiologia , Infertilidade Feminina/genética , México , Mutação , Linhagem , Gravidez , Prognóstico , Técnicas de Reprodução Assistida/estatística & dados numéricos , Resultado do Tratamento
8.
Eur J Nucl Med Mol Imaging ; 46(11): 2260-2269, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31359108

RESUMO

PURPOSE: The primary aim of the present study was to evaluate if PET/MR induced management changes versus standard of care imaging (SCI) in treated colorectal cancer patients. The secondary aim was to assess the staging performance of PET/MR and of SCI versus the final oncologic stage. METHODS: Treated CRC patients who underwent PET/MR with 18F-FDG and SCI between January 2016 and October 2018 were enrolled in this retrospective study. Their medical records were evaluated to ascertain if PET/MR had impacted on their clinical management versus SCI. The final oncologic stage, as reported in the electronic medical record, was considered the true stage of disease. RESULTS: A total of 39 patients who underwent 42 PET/MR studies were included, mean age 56.7 years (range 39-75 years), 26 males, and 13 females. PET/MR changed clinical management 15/42 times (35.7%, standard error ± 7.4%); these 15 changes in management were due to upstaging in 9/42 (21.5%) and downstaging in 6/42 (14.2%). The differences in management prompted by SCI versus PET/MR were statistically significant, and PET/MR outperformed SCI (P value < 0.001; odds ratio = 2.8). In relation to the secondary outcome, PET/MR outperformed the SCI in accuracy of oncologic staging (P value = 0.016; odds ratio = 4.6). CONCLUSIONS: PET/MR is a promising imaging tool in the evaluation of treated CRC and might change the management in these patients. However, multicenter prospective studies with larger patient samples are required in order to confirm these preliminary results.


Assuntos
Neoplasias Colorretais/diagnóstico por imagem , Neoplasias Colorretais/terapia , Imageamento por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Adulto , Idoso , Registros Eletrônicos de Saúde , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Estadiamento de Neoplasias , Estudos Retrospectivos , Resultado do Tratamento
9.
Eur J Clin Microbiol Infect Dis ; 38(1): 157-160, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30353485

RESUMO

Respiratory syncytial virus (RSV) has been recognized as responsible for severe respiratory illness in adults, especially in the elderly. While pneumonia is commonly observed during RSV infection, the burden and epidemiology of bacterial superinfection is poorly understood. The aim of this study was to identify microorganisms associated with RSV-positive pneumonia in adults. A retrospective study was conducted during three consecutive winters (October to April 2013-2016) in the University Hospital of Lyon, France. During RSV circulation periods, a systematic RSV screening was performed by reverse-transcription PCR on all respiratory samples collected from adults. Records of RSV-positive patients were subsequently analyzed to identify radiologically confirmed pneumonia cases. Bacteria were identified by standard bacteriology cultures or urinary antigen screening and classified as potentially causative of pneumonia if quantification was above the specific threshold as defined by the European Manual of Clinical Microbiology. Overall, 14,792 adult respiratory samples were screened for RSV detection by PCR. In total, 292 had a positive RSV detection (2.0%) among which 89 presented with pneumonia including 27 bacterial superinfections (9.3%) with Streptococcus pneumonia, Haemophilus influenza, Staphylococcus aureus, Pseudomonas aeruginosa, and Moraxella catarrhalis. Most patients were elderly (55.6%) and patients with comorbidities (77.8%). A more severe outcome was observed for RSV-bacteria-associated pneumonia compared with RSV pneumonia: length of stay was significantly longer (16 days vs 10 days) and ICU hospitalization more frequent (66.7% vs 21.0%) (p < 0.05). In conclusion, we did not observe major differences in the epidemiology of bacterial superinfections in RSV-positive pneumonia compared to reports on post-influenza pneumonia.


Assuntos
Pneumonia Bacteriana/microbiologia , Pneumonia Viral/microbiologia , Infecções por Vírus Respiratório Sincicial/microbiologia , Superinfecção/microbiologia , Adolescente , Adulto , Idoso , Bactérias/isolamento & purificação , Coinfecção/complicações , Coinfecção/epidemiologia , Coinfecção/microbiologia , Coinfecção/virologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia Bacteriana/complicações , Pneumonia Bacteriana/epidemiologia , Pneumonia Bacteriana/virologia , Pneumonia Viral/complicações , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Infecções por Vírus Respiratório Sincicial/complicações , Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano , Estudos Retrospectivos , Superinfecção/complicações , Superinfecção/epidemiologia , Superinfecção/virologia , Adulto Jovem
10.
J Clin Microbiol ; 56(5)2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29467193

RESUMO

The isolation of Legionella from respiratory samples is the gold standard for diagnosis of Legionnaires' disease (LD) and enables epidemiological studies and outbreak investigations. The purpose of this work was to adapt and to evaluate the performance of an amoebic coculture procedure (the amoeba plate test [APT]) for the recovery of Legionella strains from respiratory samples, in comparison with axenic culture and liquid-based amoebic coculture (LAC). Axenic culture, LAC, and APT were prospectively performed with 133 respiratory samples from patients with LD. The sensitivities and times to results for the three techniques were compared. Using the three techniques, Legionella strains were isolated in 46.6% (n = 62) of the 133 respiratory samples. The sensitivity of axenic culture was 42.9% (n = 57), that of LAC was 30.1% (n = 40), and that of APT was 36.1% (n = 48). Seven samples were positive by axenic culture only; for those samples, there were <10 colonies in total. Five samples, all sputum samples, were positive by an amoebic procedure only (5/5 samples by APT and 2/5 samples by LAC); all had overgrowth by oropharyngeal flora with axenic culture. The combination of axenic culture with APT yielded a maximal isolation rate (i.e., 46.6%). Overall, the APT significantly reduced the median time for Legionella identification to 4 days, compared with 7 days for LAC (P < 0.0001). The results of this study support the substitution of LAC by APT, which could be implemented as a second-line technique for culture-negative samples and samples with microbial overgrowth, especially sputum samples. The findings provide a logical basis for further studies in both clinical and environmental settings.


Assuntos
Amoeba/crescimento & desenvolvimento , Legionella/crescimento & desenvolvimento , Legionella/isolamento & purificação , Legionelose/diagnóstico , Técnicas Microbiológicas/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sensibilidade e Especificidade , Escarro/microbiologia , Fatores de Tempo
11.
J Sci Food Agric ; 98(9): 3409-3415, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29280145

RESUMO

BACKGROUND: Propolis is a complex mixture that honey bees produce from the exudates of various plants and presents many medicinal properties. Its chemical composition varies according to the phytogeography characteristics of each region, among others. The aim of this study was to identify and characterize the volatile organic compounds (VOCs) present in Venezuelan propolis and compare with reference samples such as Brazilian and Argentinian propolis. RESULTS: A total of 90 VOCs were identified in a series of propolis samples using both solid-phase microextraction and dynamic headspace (DHS), both coupled to a gas chromatograph-electron ionization mass spectrometer. In the case of Venezuelan propolis, sesquiterpenes, esters, aromatic compounds, and aliphatic hydrocarbons were identified. Limonene was found only in Venezuelan samples, this being the first time it has been identified in samples from this country. In the case of green propolis, ß-caryophyllene and nerolidol were the major compounds. As for the Argentinian samples, prenyl acetate, benzyl acetate, and 2-phenylethyl acetate were detected only in these samples. CONCLUSIONS: Possible chemical markers of natural sources such as limonene were detected using DHS extraction. Several compounds have also been identified for the first time in Venezuelan propolis. Cluster analysis allowed the relating of the propolis VOCs profile to their provenance. © 2017 Society of Chemical Industry.


Assuntos
Própole/química , Compostos Orgânicos Voláteis/análise , Animais , Argentina , Abelhas , Brasil , Cicloexenos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Limoneno , Sesquiterpenos/análise , Microextração em Fase Sólida , Espectrometria de Massas por Ionização por Electrospray/métodos , Terpenos/análise , Venezuela
12.
Br J Dermatol ; 176(2): 439-445, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27761891

RESUMO

BACKGROUND: According to the hygiene hypothesis, insufficient immune activation by microbes increases the risk of allergy development. Staphylococcus aureus, which is part of the skin and gut microbiota of infants in Western countries, produces a variety of T-cell-activating enterotoxins, called superantigens. OBJECTIVES: To investigate whether early (0-2 months of age) gut colonization by S. aureus strains that carry specific superantigens and adhesins was related to subsequent development of atopic eczema in a Swedish birth cohort. METHODS: Staphylococcus aureus was isolated from rectal swabs and cultured quantitatively from faecal samples, with individual strains being tested for carriage of genes for superantigens and adhesins. Atopic eczema was diagnosed at onset of symptoms and at 18 months of age. RESULTS: Although the frequency of early gut colonization by S. aureus was not related to subsequent eczema development, the S. aureus strains that were found to colonize those infants who developed atopic eczema were less likely to carry the gene encoding the superantigen SElM (P = 0·008) and the gene for elastin-binding protein (P = 0·03), compared with strains that were isolated from infants who had not developed atopic eczema by 18 months of age. CONCLUSIONS: Gut colonization by S. aureus strains carrying a certain combination of superantigen and adhesin genes was negatively associated with subsequent development of atopic eczema. Such strains may provide stimulation and promote maturation of the infant immune system.


Assuntos
Adesinas Bacterianas/imunologia , Dermatite Atópica/etiologia , Microbioma Gastrointestinal/imunologia , Staphylococcus aureus/imunologia , Superantígenos/metabolismo , Adesinas Bacterianas/genética , Pré-Escolar , Colo/microbiologia , Dermatite Atópica/imunologia , Enterotoxinas/genética , Fezes/microbiologia , Humanos , Lactente , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação
13.
Folia Med (Plovdiv) ; 59(3): 289-297, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28976893

RESUMO

BACKGROUND: The palmaris longus muscle is one of the most variable muscles in the human body and there have been numerous variations reported. The different palmaris longus variations are interesting not only from an anatomical point of view, but they could also have definite clinical significance. AIM: The aim of this study was to examine the different types of variations of palmaris longus muscle in the Bulgarian population. MATERIALS AND METHODS: Over a period of 15 years, 56 formol-carbol fixed human cadavers were studied to investigate the different variations of palmaris longus muscle (PLM). RESULTS: Various anatomical variations of PLM have been reported: absence (2.68%); reversed palmaris longus coexisting with an additional abductor digiti minimi muscle (0.89%); digastric (0.89%); palmaris longus with intermediate muscle belly (1.79%) and duplication (1.79%). CONCLUSIONS: To reveal the wide variety of the types of palmaris longus muscle and their importance for clinical practice, we make a brief literature review concerning the different types of variations, their role in the median and ulnar neuropathy in the wrist or as structures simulating a soft tissue tumour and the application of palmaris longus tendon in plastic and reconstructive surgery as grafting material. We also present new systematic anatomical and clinical classifications of palmaris longus variations by dividing them into two simple groups.


Assuntos
Antebraço/anatomia & histologia , Músculo Esquelético/anatomia & histologia , Idoso , Idoso de 80 Anos ou mais , Bulgária , Cadáver , Dissecação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tendões/anatomia & histologia , Articulação do Punho/fisiologia
14.
Inorg Chem ; 55(21): 11522-11528, 2016 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-27775334

RESUMO

Noble metal nanoclusters (NCs) play a pivotal role in bridging the gap between molecules and quantum dots. Fundamental understanding of the evolution of the structural, optical, and electronic properties of these materials in various environments is of paramount importance for many applications. Using state-of-the-art spectroscopy, we provide the first decisive experimental evidence that the structural, electronic, and optical properties of Ag44(MNBA)30 NCs can now be tailored by controlling the chemical environment. Infrared and photoelectron spectroscopies clearly indicate that there is a dimerization between two adjacent ligands capping the NCs that takes place upon lowering the pH from 13 to 7.

15.
Genet Mol Biol ; 39(1): 24-9, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27007894

RESUMO

Prostate cancer is the second most common cancer among men in western populations, and despite its high mortality, its etiology remains unknown. Inflammatory processes are related to the etiology of various types of tumors, and prostate inflammation, in particular, has been associated with prostate cancer carcinogenesis and progression. Human papillomavirus (HPV) is associated with benign and malignant lesions in the anogenital tract of both females and males. The possible role of HPV in prostate carcinogenesis is a subject of great controversy. In this study, we aimed to examine the prevalence of HPV infections in prostate carcinomas of patients from northeastern Brazil. This study included 104 tissue samples from primary prostate carcinoma cases. HPV DNA was purified and then amplified using MY09/11 and GP5+/GP6+ degenerate primer sets that detect a wide range of HPV types, and with specific PCR primers sets for E6 and E7 HPV regions to detect HPV 16. None of the samples showed amplification products of HPV DNA for primer sets MY09/11 and GP5+/GP6+, or the specific primer set for the E6 and E7 HPV regions. HPV infection, thus, does not seem to be one of the causes of prostate cancer in the population studied.

16.
Angew Chem Int Ed Engl ; 55(19): 5749-53, 2016 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-27060602

RESUMO

A high quantum yield (QY) of photoluminescence (PL) in nanomaterials is necessary for a wide range of applications. Unfortunately, the weak PL and moderate stability of atomically precise silver nanoclusters (NCs) suppress their utility. Herein, we accomplished a ≥26-fold PL QY enhancement of the Ag29 (BDT)12 (TPP)4 cluster (BDT: 1,3-benzenedithiol; TPP: triphenylphosphine) by doping with a discrete number of Au atoms, producing Ag29-x Aux (BDT)12 (TPP)4 , x=1-5. The Au-doped clusters exhibit an enhanced stability and an intense red emission around 660 nm. Single-crystal XRD, mass spectrometry, optical, and NMR spectroscopy shed light on the PL enhancement mechanism and the probable locations of the Au dopants within the cluster.

17.
J Am Chem Soc ; 137(37): 11970-5, 2015 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-26104755

RESUMO

The bottom-up assembly of nanoparticles into diverse ordered solids is a challenge because it requires nanoparticles, which are often quasi-spherical, to have interaction anisotropy akin to atoms and molecules. Typically, anisotropy has been introduced by changing the shape of the inorganic nanoparticle core. Here, we present the design, self-assembly, optical properties, and total structural determination of Ag29(BDT)12(TPP)4, an atomically precise tetravalent nanocluster (NC) (BDT, 1,3-benzenedithiol; TPP, triphenylphosphine). It features four unique tetrahedrally symmetrical binding surface sites facilitated by the supramolecular assembly of 12 BDT (wide footprint bidentate thiols) in the ligand shell. When each of these sites was selectively functionalized by a single phosphine ligand, particle stability, synthetic yield, and the propensity to self-assemble into macroscopic crystals increased. The solid crystallized NCs have a substantially narrowed optical band gap compared to that of the solution state, suggesting strong interparticle electronic coupling occurs in the solid state.

18.
Eur J Clin Microbiol Infect Dis ; 34(7): 1443-9, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25864191

RESUMO

Staphylococcus aureus is both a component of the normal skin flora and an important pathogen. It expresses a range of recognized and putative virulence factors, such as enterotoxins with superantigenic properties. Several superantigen genes, i.e., seg, sei, selm, seln, and selo, are encoded by the enterotoxin gene cluster (egc), which is found in the majority of S. aureus isolates. Carriage of egc is associated with fitness of S. aureus in the gut microbiota, but it is not known if it contributes to pathogenicity. We constructed egc+ (functional for the seg, selm, and selo genes) and isogenic egc- S. aureus mutants, and investigated their virulence profiles in murine infection models. No effect of egc was seen in a local skin and soft tissue infection model, but in an invasive infection model, increased weight loss was observed after infection with the egc+ as compared to the egc- mutant. Mortality and arthritis were not affected by egc status. Our data suggest that egc has limited effects on the virulence of S. aureus. It may primarily function as a colonization factor increasing commensal fitness, although it might have some aggravating effects on the infection when the bacteria reach the blood.


Assuntos
Enterotoxinas/genética , Família Multigênica , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Superantígenos/genética , Animais , Modelos Animais de Doenças , Feminino , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Loci Gênicos , Humanos , Camundongos , Mutação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Infecções Estafilocócicas/mortalidade , Infecções Estafilocócicas/patologia , Staphylococcus aureus/patogenicidade
19.
Eur J Clin Microbiol Infect Dis ; 34(9): 1803-7, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26092030

RESUMO

The Sofia Legionella Fluorescence Immunoassay (FIA; Quidel) is a recently introduced rapid immunochromatographic diagnostic test for Legionnaires' disease using immunofluorescence technology designed to enhance its sensitivity. The aim of this study was to evaluate its performance for the detection of urinary antigens for Legionella pneumophila serogroup 1 in two National Reference Centers for Legionella. The sensitivity and specificity of the Sofia Legionella FIA test were determined in concentrated and nonconcentrated urine samples, before and after boiling, in comparison with the BinaxNOW® Legionella Urinary Antigen Card (UAC; Alere). Compared with BinaxNOW® Legionella UAC, the sensitivity of the Sofia Legionella test was slightly higher in nonconcentrated urine samples and was identical in concentrated urine samples. The specificity of the Sofia Legionella FIA test was highly reduced by the concentration of urine samples. In nonconcentrated samples, a lack of specificity was observed in 2.3 % of samples, all of them resolved by heat treatment. The Sofia Legionella FIA is a sensitive test for detecting Legionella urinary antigens with no previous urine concentration. However, all positive samples have to be re-tested after boiling to reach a high specificity. The reading is automatized on the Sofia analyzer, which can be connected to laboratory information systems, facilitating accurate and rapid reporting of results.


Assuntos
Antígenos de Bactérias/urina , Fluorimunoensaio/métodos , Técnicas Imunoenzimáticas/métodos , Legionella pneumophila/classificação , Doença dos Legionários/diagnóstico , Antígenos de Bactérias/imunologia , Humanos , Legionella pneumophila/imunologia , Doença dos Legionários/microbiologia , Sensibilidade e Especificidade
20.
Eur J Clin Microbiol Infect Dis ; 34(5): 927-33, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25575949

RESUMO

Recent research on Staphylococcus aureus vaccine development has focused on active immunization against Panton-Valentine leukocidin (PVL), a potent leukotoxin associated with both superficial and severe deep-seated infections. PVL prevalence is highly variable worldwide, but it is unknown to what extent immunity to PVL varies between patients from geographic areas with different PVL-positive S. aureus prevalences. We conducted a retrospective multicentric study of anti-PVL and anti-alpha-toxin (Hla) antibody levels in uninfected adult patients from France (low PVL prevalence; n = 200), Algeria (moderate prevalence; n = 143), and Senegal (high prevalence; n = 228). The antibody levels were quantified by an enzyme-linked immunosorbent assay (ELISA) procedure. Because Hla is present in virtually all S. aureus strains, its corresponding antibody levels were considered to reflect population exposure to S. aureus. Compared with French participants, the average anti-PVL antibody levels were 2.5-fold and 8.2-fold higher in Algerian and Senegalese participants, respectively (p < 0.001). Conversely, anti-Hla antibody levels did not differ between participants from the three countries, suggesting that the observed differences in anti-PVL antibody levels were not biased by variations in population exposure to S. aureus. Hence, anti-PVL antibody levels in the general populations of France, Algeria, and Senegal vary widely and match variations in PVL-positive S. aureus strain prevalence, with an increasing north-to-south gradient. To conclude, immunity to PVL in a given population correlates with local PVL prevalence. This finding can help to inform PVL vaccine strategies.


Assuntos
Anticorpos Antibacterianos/sangue , Toxinas Bacterianas/imunologia , Exotoxinas/imunologia , Leucocidinas/imunologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/imunologia , Adulto , Idoso , Argélia/epidemiologia , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , França/epidemiologia , Geografia , Proteínas Hemolisinas/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Senegal/epidemiologia , Estudos Soroepidemiológicos
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