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1.
Artigo em Inglês | MEDLINE | ID: mdl-32627891

RESUMO

Efficiency in charge-transport is a fundamental but demanding prerequisite to allow better exploitation of molecular functionalities in organic electronics and energy-conversion systems. Here, we report on a mechanism that enables a one-dimensional conductance structure by connecting discrete molecular states at 2.1eV through the pores of a metal-organic network on Cu(110). Two adjacent, periodic and isoenergetic contributions, namely a molecular resonance and the confined surface-state, add-up leading to anisotropic structures, as channels, observable in real-space conductance images. The adsorption configurations of Br atoms, inorganic byproduct of the redox-reacted 4,7-dibromobenzo[c]-1,2,5-thiadiazole (2Br-BTD) molecules on the copper surface, drive the confinement of the Cu surface state within the pores and critically control the channel continuity. Small displacements of the Br atoms change the local surface potential misaligning the energy levels. This work visualizes the effect of order-disorder transitions caused by the movement of single atoms in the electronic properties of two-dimensional organic networks.

2.
J Am Chem Soc ; 140(46): 15631-15634, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30394739

RESUMO

Copper is the paradigmatic catalyzer of the Ullmann cross-coupling reaction. Despite this, its role in the reaction is still under debate. Here, we shed light on the mechanistic steps of debromination, characterizing a prototypical molecule, namely 4,7-dibromobenzo[ c]-1,2,5-thiadiazole (2Br-BTD), deposited on a Cu(110) surface. By means of scanning probe techniques and first principle calculations, we demonstrate the oxidative addition of Cu atoms leading to a -C-Cu-Br metal-organic complex. The scission of the strongly bound bromine atoms requires the cooperative action of neighboring complexes resulting in the formation of Cu-coordinated BTD structures.

3.
Mycoses ; 61(1): 11-21, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28940753

RESUMO

Candida spp. are responsible for 80% of all systemic fungal infections and are associated with high mortality rates. This study characterised 79 bloodstream isolates of C. albicans, C. glabrata, C. orthopsilosis, C. parapsilosis and C. tropicalis from patients in a Brazilian hospital. The susceptibility to amphotericin B, caspofungin, fluconazole and voriconazole was determined; virulence factor production was assessed based on haemolysin, phospholipase and proteinase activities, and the patients' clinical characteristics were analysed. C. albicans was the predominant species (44%), followed by C. glabrata (19%), C. tropicalis (19%), C. parapsilosis (14%) and C. orthopsilosis (4%). The candidemia incidence was 1.52 per 1000 admissions, and the crude mortality rate was 52%. One C. albicans isolate was resistant to fluconazole and voriconazole. Moreover, 20.2%, 2.5% and 3.8% of the isolates exhibited dose-dependent susceptibility to fluconazole, voriconazole and caspofungin, respectively. In conclusion, although the C. glabrata incidence was higher than that usually described in Brazil, its increase was previously observed in studies conducted worldwide. Furthermore, the azole resistance of the C. albicans isolate could be due to previous exposure to these antifungals. These results highlight the importance of epidemiological studies and will facilitate an improved understanding of candidemia in the studied hospital.


Assuntos
Antifúngicos/farmacologia , Candida/classificação , Candidemia/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Candida/efeitos dos fármacos , Candida/isolamento & purificação , Candida/patogenicidade , Candida glabrata/efeitos dos fármacos , Candida glabrata/isolamento & purificação , Candida glabrata/patogenicidade , Candidemia/epidemiologia , Candidemia/mortalidade , Criança , Pré-Escolar , Farmacorresistência Fúngica , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Prevalência , Centros de Atenção Terciária , Fatores de Virulência , Adulto Jovem
4.
Nanoscale ; 9(44): 17342-17348, 2017 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-29094126

RESUMO

Here, we show that the electronic properties of a surface-supported 2-dimensional (2D) layer structure can self-texturize at nanoscale. The local electronic properties are determined by structural relaxation processes through variable adsorption stacking configurations. We demonstrate that the spatially modulated layer-buckling, which arises from the lattice mismatch and the layer/substrate coupling at the GdAu2/Au(111) interface, is sufficient to locally open an energy gap of ∼0.5 eV at the Fermi level in an otherwise metallic layer. Additionally, this out-of-plane displacement of the Gd atoms patterns the character of the hybridized Gd-d states and shifts the center of mass of the Gd 4f multiplet proportionally to the lattice distortion. These findings demonstrate the close correlation between the electronic properties of the 2D-layer and its planarity. We demonstrate that the resulting template shows different chemical reactivities which may find important applications.

5.
Artigo em Inglês | MEDLINE | ID: mdl-28793019

RESUMO

One of the factors causing treatment failure in cryptococcosis is the resistance of Cryptococcus spp. to antifungal drugs, which has motivated the susceptibility assessment of isolates from patients with cryptococcosis, different clinical conditions and infections outcomes. Clinical isolates of Cryptococcus spp. from three different groups of patients were studied in the present investigation: 19 HIV-positive patients with relapsing and/or refractory meningitis (Group 1), 30 HIV-positive patients who experienced a single and limited episode of cryptococcosis (Group 2), and 19 HIV-negative patients with cryptococcosis (Group 3). Eighty C. neoformans var. grubii isolates and 7 C. gattii isolates were studied. The minimum inhibitory concentration (MIC) of amphotericin B, azole drugs and flucytosine was determined for Cryptococcus spp. by broth microdilution test and E-test. The MIC50 and MIC90 were 0.25 and 0.50 µg/mL for amphotericin B, 4.0 and 8.0 µg /mL for fluconazole, 0.06 and 0.25 µg/mL for itraconazole, 0.25 and 0.50 µg/mL for voriconazole, and 8.0 and 16.0 µg/mL for flucytosine, respectively. Amphotericin B and itraconazole showed higher MICs for C. neoformans var. grubii and C. gattii, respectively. The MICs of fluconazole and itraconazole obtained with the E-test were higher than those obtained with broth microdilution. Isolates from non-HIV coinfected were less sensitive to the azoles. There was no difference in the susceptibility of C. neoformans var. grubii isolates from patients with a favorable or unfavorable outcome or along the episodes of relapsing and/or refractory meningitis.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Antifúngicos/farmacologia , Cryptococcus gattii/efeitos dos fármacos , Cryptococcus neoformans/efeitos dos fármacos , Meningite Criptocócica/microbiologia , Cryptococcus gattii/isolamento & purificação , Cryptococcus neoformans/isolamento & purificação , Farmacorresistência Fúngica , Humanos , Testes de Sensibilidade Microbiana
6.
Adv Sci (Weinh) ; 3(9): 1600187, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27711268

RESUMO

A trigon structure formed by submonolayer gadolinium deposition onto Au(111) is revealed as a robust growth template for Co nanodot arrays. Scanning Tunneling Microscopy and X-Ray Magnetic Circular Dichroism measurements evidence that the Co nanoislands behave as independent magnetic entities with an out-of-plane easy axis of anisotropy and enhanced magnetic anisotropy values, as compared to other self-organized Co nanodot superlattices. The large strain induced by the lattice mismatch at the interface between Co and trigons is discussed as the main reason for the increased magnetic anisotropy of the nanoislands.

7.
Am J Trop Med Hyg ; 94(5): 975-81, 2016 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-26928832

RESUMO

Refractory and relapsing crytocococcosis in acquired immune deficiency syndrome (AIDS) patients have a poor prognosis. The risk factors for this complicated infection course were evaluated by comparing refractory and/or relapsing cryptococcosis in human immunodeficiency virus-coinfected patients (cohort 1) with another group of AIDS patients who adequately responded to antifungals (cohort 2). Except for one isolate of Cryptococcus gattii from a cohort 2 case, all other isolates were identified as Cryptococcus neoformans var. grubii, sex type α, genotype VNI, including Cryptococcus reisolated from the relapse or in the refractory state. No differences were observed with respect to Cryptococcus capsule size and in the melanin and phospholipase production. The cohort 1 patients presented higher prevalence of cryptococcemia, cerebral dissemination, chronic liver disease, and leucopenia, and have increased death rate. Apparently, the refractory and/or relapsing cryptococcosis in the AIDS patients were more related to the host and the extent of the infection than to the fungal characteristics.


Assuntos
Síndrome de Imunodeficiência Adquirida/complicações , Síndrome de Imunodeficiência Adquirida/patologia , Criptococose/complicações , Criptococose/patologia , Cryptococcus/genética , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Infecções Oportunistas Relacionadas com a AIDS/patologia , Adulto , Anfotericina B/uso terapêutico , Antifúngicos/uso terapêutico , Coinfecção , Cryptococcus/metabolismo , Ácido Desoxicólico/uso terapêutico , Combinação de Medicamentos , Feminino , Genótipo , Humanos , Masculino , Fatores de Virulência
8.
ACS Nano ; 10(2): 2644-51, 2016 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-26841052

RESUMO

The tunable properties of molecular materials place them among the favorites for a variety of future generation devices. In addition, to maintain the current trend of miniaturization of those devices, a departure from the present top-down production methods may soon be required and self-assembly appears among the most promising alternatives. On-surface synthesis unites the promises of molecular materials and of self-assembly, with the sturdiness of covalently bonded structures: an ideal scenario for future applications. Following this idea, we report the synthesis of functional extended nanowires by self-assembly. In particular, the products correspond to one-dimensional organic semiconductors. The uniaxial alignment provided by our substrate templates allows us to access with exquisite detail their electronic properties, including the full valence band dispersion, by combining local probes with spatial averaging techniques. We show how, by selectively doping the molecular precursors, the product's energy level alignment can be tuned without compromising the charge carrier's mobility.

9.
Int J Dent ; 2014: 475859, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25258628

RESUMO

Objectives. Bisphosphonates related osteonecrosis of the jaw (BRONJ) is a pathological condition characterized by bone exposure or latent infection in patients treated with the drug. The aim of the study is to monitor the BRONJ level of risk health in patients with cancer, according to a preventive clinical protocol, which is firstly aimed at reducing risk factors such as the periodontal infections. Materials and Methods. 10 patients participated in the protocol and were evaluated at baseline and after 3 and 18 months of treatment with bisphosphonates, through full mouth plaque and bleeding scores (FMPS and FMBS), clinical attachment level (CAL) measurement, and the occurrence of osteonecrosis. Results. The mean plaque and bleeding were reduced and the CAL has not shown significant changes and in no cases was there manifestation of BRONJ. Conclusion. The protocol proved crucial for the maintenance of good oral health conditions by eliminating the risk of BRONJ during the observation period.

10.
Nano Lett ; 14(6): 2977-81, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24798248

RESUMO

Controlling anisotropy and exchange coupling in patterned magnetic nanostructures is the key for developing advanced magnetic storage and spintronic devices. We report on the antiferromagnetic interaction between a Co nanodot array and its supporting GdAu2 nanotemplate that induces large anisotropy values in individual Co nanodots. In clear contrast with nonmagnetic Au substrates, GdAu2 triggers an earlier switch from out-of-plane anisotropy in monatomic high dots to in-plane when the dot height becomes biatomic.

11.
J Clin Microbiol ; 52(7): 2530-5, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24808234

RESUMO

In this study, we report the early expansion, evolution, and characterization of a multiresistant Klebsiella pneumoniae clone that was isolated with increasing frequency from inpatients in a tertiary-care university hospital in Brazil. Seven carbapenem- and quinolone-resistant and polymyxin B-susceptible or -resistant K. pneumoniae isolates isolated between December 2012 and February 2013 were investigated. Beta-lactamase- and plasmid-mediated quinolone resistance (PMQR)-encoding genes and the genetic environment were investigated using PCR, sequencing, and restriction fragment length polymorphism (RFLP). Clonal relatedness was established using XbaI-pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and phylogenetic group characterization. Plasmid analyses included PCR-based replicon typing (PBRT) and hybridization of the S1-PFGE product, plasmid MLST, and conjugation experiments. Virulence potential was assessed by PCR by searching for 10 virulence factor-encoding genes (ureA, fimH, kfuBC, uge, wabG, magA, mrkD, allS, rmpA, and cf29a) and by phenotypic tests to analyze the hypermucoviscous phenotype. The genetic context of a multidrug-resistant and extensively drug-resistant K. pneumoniae ST11-KpI clone harboring IncFIIk-Tn4401a-blaKPC-2, qnrS1, and blaCTX-M-2 was found. Moreover, three isolates displayed high resistance to polymyxin B (MICs = 32, 32, and 128 mg/liter) as well as mucous and hypermucoviscous phenotypes. These bacteria also harbored ureA, fimH, uge, wabG, and mrkD, which code for virulence factors associated with binding, biofilm formation, and the ability to colonize and escape from phagocytosis. Our study describes the association of important coresistance and virulence factors in the K. pneumoniae ST11 international high-risk clone, which makes this pathogen successful at infections and points to the quick expansion and evolution of this multiresistant and virulent clone, leading to a pandrug-resistant phenotype and persistent bacteria in a Brazilian hospital.


Assuntos
Farmacorresistência Bacteriana Múltipla , Evolução Molecular , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/genética , beta-Lactamases/metabolismo , Adulto , Idoso , Brasil/epidemiologia , Análise por Conglomerados , Feminino , Genes Bacterianos , Genótipo , Hospitais Universitários , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Epidemiologia Molecular , Tipagem Molecular , Filogenia , Plasmídeos , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNA , Adulto Jovem , beta-Lactamases/genética
12.
Rev Soc Bras Med Trop ; 46(3): 299-303, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23856877

RESUMO

INTRODUCTION: Pseudomonas aeruginosa isolates related to nosocomial infections are often resistant to multiple antibacterial agents. In this study, antimicrobial combinations were evaluated to detect in vitro synergy against clinical isolates of P. aeruginosa. METHODS: Four clinical P. aeruginosa isolates were selected at random among other isolates from inpatients treated at the public University hospital in Ribeirão Preto, SP, Brazil. Two isolates were susceptible to imipenem (IPM-S) and several other antimicrobials, while the other two isolates were imipenem and multidrug resistant (IPM-R). The checkerboard method was used to assess the interactions between antimicrobials. RESULTS: Combinations of imipenem or other anti-Pseudomonas drugs with complementary antibiotics, such as aminoglycosides, fosfomycin and rifampin, reached synergy rates of 20.8%, 50%, 62.5% and 50% for the two IPM-S and two IPM-R Pseudomonas isolates, respectively. Imipenem, piperacillin-tazobactam and ceftazidime yielded a greater synergy rate than cefepime or ciprofloxacin. Synergist combinations were more commonly observed when the complementary drug was tobramycin (65%) or fosfomycin (57%). CONCLUSIONS: Some antibacterial combinations led to significant reductions of the minimum inhibitory concentrations of both drugs, suggesting that they could be clinically applied to control infections caused by multidrug-resistant P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Pseudomonas aeruginosa/efeitos dos fármacos , Sinergismo Farmacológico , Quimioterapia Combinada/métodos , Testes de Sensibilidade Microbiana
13.
Rev. Soc. Bras. Med. Trop ; 46(3): 299-303, May-Jun/2013. tab
Artigo em Inglês | LILACS | ID: lil-679527

RESUMO

Introduction Pseudomonas aeruginosa isolates related to nosocomial infections are often resistant to multiple antibacterial agents. In this study, antimicrobial combinations were evaluated to detect in vitro synergy against clinical isolates of P. aeruginosa. Methods Four clinical P. aeruginosa isolates were selected at random among other isolates from inpatients treated at the public University hospital in Ribeirão Preto, SP, Brazil. Two isolates were susceptible to imipenem (IPM-S) and several other antimicrobials, while the other two isolates were imipenem and multidrug resistant (IPM-R). The checkerboard method was used to assess the interactions between antimicrobials. Results Combinations of imipenem or other anti-Pseudomonas drugs with complementary antibiotics, such as aminoglycosides, fosfomycin and rifampin, reached synergy rates of 20.8%, 50%, 62.5% and 50% for the two IPM-S and two IPM-R Pseudomonas isolates, respectively. Imipenem, piperacillin-tazobactam and ceftazidime yielded a greater synergy rate than cefepime or ciprofloxacin. Synergist combinations were more commonly observed when the complementary drug was tobramycin (65%) or fosfomycin (57%). Conclusions Some antibacterial combinations led to significant reductions of the minimum inhibitory concentrations of both drugs, suggesting that they could be clinically applied to control infections caused by multidrug-resistant P. aeruginosa. .


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Pseudomonas aeruginosa/efeitos dos fármacos , Sinergismo Farmacológico , Quimioterapia Combinada/métodos , Testes de Sensibilidade Microbiana
14.
Rev Soc Bras Med Trop ; 46(1): 79-83, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23563830

RESUMO

INTRODUCTION: Amphotericin B, azole or sulfamide drugs are used for treatment of patients with paracoccidioidomycosis. Among the azole drugs, voriconazole was active in vitro against Paracoccidioides brasiliensis and showed efficacy in the treatment of patients infected with this fungus.In the present study the antifungal activity of voriconazole and of other drugs was compared in a rat model of paracoccidioidomycosis. METHODS: Wistar rats were inoculated intravenously with the BOAS strain of P. brasiliensis and antifungal drugs were administered to the animals by gavage at the following doses (mg/kg weight/day): voriconazole (5 to 20), ketoconazole (12 to 15), fluconazole (6), itraconazole (4), and sulfamethoxazole-trimethoprim (120 to 150). The antifungal activity of the drugs was assessed by determining the P. brasiliensis colony forming units in the lungs and spleen of the animals at the end of treatment and by a survival study. RESULTS: Voriconazole reduced the total tissue fungal burden of P. brasiliensis, particularly at doses of ≥ 10 mg/kg weight/day but its antifungal activity was less intense than that of fluconazole, itraconazole and sulfamethoxazole-trimethoprim. The mean survival of animals treated with the last three drugs, 29.1 ± 10.7, 26.1 ± 10.1 and 28.4 ± 9.6 days, respectively, was higher than that achieved with voriconazole 10mg/kg weight/day (18.5 ± 8.3 days) and that observed in untreated animals (15.7 ± 3.6 days). CONCLUSIONS: At doses similar to those used for clinical treatment, voriconazole showed lower antifungal activity in experimental rat paracoccidioidomycosis than that obtained with itraconazole and sulfamethoxazole-trimethoprim.


Assuntos
Antifúngicos/farmacologia , Paracoccidioidomicose/tratamento farmacológico , Animais , Modelos Animais de Doenças , Feminino , Pirimidinas/farmacologia , Ratos , Ratos Wistar , Triazóis/farmacologia , Voriconazol
15.
Rev. Soc. Bras. Med. Trop ; 46(1): 73-78, Jan.-Feb. 2013. ilus, tab
Artigo em Inglês | LILACS | ID: lil-666799

RESUMO

INTRODUCTION: Amphotericin B, azole or sulfamide drugs are used for treatment of patients with paracoccidioidomycosis. Among the azole drugs, voriconazole was active in vitro against Paracoccidioides brasiliensis and showed efficacy in the treatment of patients infected with this fungus.In the present study the antifungal activity of voriconazole and of other drugs was compared in a rat model of paracoccidioidomycosis. METHODS: Wistar rats were inoculated intravenously with the BOAS strain of P. brasiliensis and antifungal drugs were administered to the animals by gavage at the following doses (mg/kg weight/day): voriconazole (5 to 20), ketoconazole (12 to 15), fluconazole (6), itraconazole (4), and sulfamethoxazole-trimethoprim (120 to 150). The antifungal activity of the drugs was assessed by determining the P. brasiliensis colony forming units in the lungs and spleen of the animals at the end of treatment and by a survival study. RESULTS: Voriconazole reduced the total tissue fungal burden of P. brasiliensis, particularly at doses of ≥10mg/kg weight/day but its antifungal activity was less intense than that of fluconazole, itraconazole and sulfamethoxazole-trimethoprim. The mean survival of animals treated with the last three drugs, 29.1±10.7, 26.1± 10.1 and 28.4±9.6 days, respectively, was higher than that achieved with voriconazole 10mg/kg weight/day (18.5±8.3 days) and that observed in untreated animals (15.7±3.6 days). CONCLUSIONS: At doses similar to those used for clinical treatment, voriconazole showed lower antifungal activity in experimental rat paracoccidioidomycosis than that obtained with itraconazole and sulfamethoxazole-trimethoprim.


Assuntos
Animais , Feminino , Ratos , Antifúngicos/farmacologia , Paracoccidioidomicose/tratamento farmacológico , Modelos Animais de Doenças , Pirimidinas/farmacologia , Ratos Wistar , Triazóis/farmacologia
16.
ACS Nano ; 5(2): 1360-5, 2011 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-21244042

RESUMO

The asymmetric molecule 4-[trans-2-(pyrid-4-yl-vinyl)] benzoic acid (PVBA) adsorbed on Cu(111) is characterized by scanning tunneling microscopy (STM) and density functional theory (DFT) to determine the influence of subsurface atomic layers on the adsorption. In contrast to the 6-fold symmetry of the first atomic layer of close-packed surfaces, we find that the arrangement of the isolated molecules follows predominantly a 3-fold symmetry. This reduction in symmetry, where the molecule selects a specific orientation along the ⟨-211⟩ axes, reveals the contribution of lower-lying Cu layers to the molecular arrangement. Our calculations rationalize the interaction of the substrate with the molecule in terms of electrostatic screening and local relaxation phenomena.

17.
Mem Inst Oswaldo Cruz ; 105(7): 904-7, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21120361

RESUMO

Paracoccidioidomycosis should be differentiated from other opportunistic diseases in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients who live in Latin America. Laboratory investigation can begin with serological tests, which are rapid and efficient. In the present study, double immunodiffusion (DID), counterimmunoelectrophoresis (CIEP) and an enzyme linked immunosorbent assay (ELISA) tests were assessed for the detection of anti-Paracoccidioides brasiliensis antibodies in 40 patients coinfected with HIV. The results were compared to those obtained for 75 non-HIV-infected patients with endemic paracoccidioidomycosis. Anti-P. brasiliensis antibodies were detected in 65% (DID), 79% (CIEP) and 95% (ELISA) of the patients with HIV/AIDS, significantly lower rates than those detected in cases of endemic paracoccidioidomycosis, which were 89%, 99% and 100%, respectively. The reactive sera of HIV-infected patients also showed lower anti-P. brasiliensis antibody titres than those of non-HIV-infected patients. Despite the lower intensity of the specific humoral response, serological tests are useful for the diagnosis of opportunistic paracoccidioidomycosis in the HIV/AIDS population. We suggest optimization of the laboratory diagnosis by combining the ELISA test with CIEP or DID.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Anticorpos Antifúngicos/sangue , Paracoccidioides/imunologia , Paracoccidioidomicose/diagnóstico , Adolescente , Adulto , Contraimunoeletroforese , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunodifusão , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Adulto Jovem
18.
Mem. Inst. Oswaldo Cruz ; 105(7): 904-907, Nov. 2010. graf, tab
Artigo em Inglês | LILACS | ID: lil-566181

RESUMO

Paracoccidioidomycosis should be differentiated from other opportunistic diseases in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients who live in Latin America. Laboratory investigation can begin with serological tests, which are rapid and efficient. In the present study, double immunodiffusion (DID), counterimmunoelectrophoresis (CIEP) and an enzyme linked immunosorbent assay (ELISA) tests were assessed for the detection of anti-Paracoccidioides brasiliensis antibodies in 40 patients coinfected with HIV. The results were compared to those obtained for 75 non-HIV-infected patients with endemic paracoccidioidomycosis. Anti-P. brasiliensis antibodies were detected in 65 percent (DID), 79 percent (CIEP) and 95 percent (ELISA) of the patients with HIV/AIDS, significantly lower rates than those detected in cases of endemic paracoccidioidomycosis, which were 89 percent, 99 percent and 100 percent, respectively. The reactive sera of HIV-infected patients also showed lower anti-P. brasiliensis antibody titres than those of non-HIV-infected patients. Despite the lower intensity of the specific humoral response, serological tests are useful for the diagnosis of opportunistic paracoccidioidomycosis in the HIV/AIDS population. We suggest optimization of the laboratory diagnosis by combining the ELISA test with CIEP or DID.


Assuntos
Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Infecções Oportunistas Relacionadas com a AIDS , Anticorpos Antifúngicos/sangue , Paracoccidioides/imunologia , Paracoccidioidomicose , Contraimunoeletroforese , Ensaio de Imunoadsorção Enzimática , Imunodifusão , Sensibilidade e Especificidade
19.
J Am Chem Soc ; 132(34): 11900-1, 2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20698538

RESUMO

The magnetic properties of isolated TbPc(2) molecules supported on a Cu(100) surface are investigated by X-ray magnetic circular dichroism at 8 K in magnetic fields up to 5 T. The crystal field and magnetic properties of single molecules are found to be robust upon adsorption on a metal substrate. The Tb magnetic moment has Ising-like magnetization; XMCD spectra combined with multiplet calculations show that the saturation orbital and spin magnetic moment values reach 3 and 6 mu(B), respectively.


Assuntos
Complexos de Coordenação/química , Cobre/química , Magnetismo , Adsorção , Anisotropia , Dicroísmo Circular , Tamanho da Partícula , Propriedades de Superfície
20.
Nano Lett ; 10(8): 2995-3000, 2010 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-20597466

RESUMO

Electrically tunable molecules are highly attractive for the construction of molecular devices, such as switches, transistors, or machines. Here, we present a novel nanomechanical element triggered by an electrical bias as external stimulus. We demonstrate that a transitory chemical bond between a copper atom and coordinating organic molecules adsorbed on a metal surface acts as variable frequency switch, which can be actuated and probed by means of low-temperature scanning tunneling microscopy. Whereas below a threshold bias voltage the bond is permanently either formed or broken the bonding state continuously oscillates at higher voltages. The switching rate of the bistable molecular system can be widely tuned from below 1 Hz up to the kilohertz regime. The quantum yield per tunneling electron to trigger a transition between the two states varies spatially and is related to the local density of states of the bonded and nonbonded configuration.

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