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1.
Anal Chem ; 96(19): 7558-7565, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38696396

RESUMO

With a view to potentiometric sensing with minimal calibration requirements and high long-term stability, colloid-imprinted mesoporous (CIM) carbon was functionalized by the covalent attachment of a cobalt redox buffer and used as a new solid contact for ion-selective electrodes (ISEs). The CIM carbon surface was first modified by electroless grafting of a terpyridine ligand (Tpy-ph) using diazonium chemistry, followed by stepwise binding of Co(II) and an additional Tpy ligand to the grafted ligand, forming a bis(terpyridine) Co(II) complex, CIM-ph-Tpy-Co(II)-Tpy. Half a molar equivalent of ferrocenium tetrakis(3-chlorophenyl)borate was then used to partially oxidize the Co(II) complex. Electrodes prepared with this surface-attached CIM-ph-Tpy-Co(III/II)-Tpy redox buffer as a solid contact were tested as K+ sensors in combination with valinomycin as the ionophore and Dow 3140 silicone or plasticized poly(vinyl chloride) (PVC) as the matrixes for the ion-selective membrane (ISM). This solid contact is characterized by a redox capacitance of 3.26 F/g, ensuring a well-defined interfacial potential that underpins the transduction mechanism. By use of a redox couple as an internal reference element to control the phase boundary potential at the interface of the ISM and the CIM carbon solid contact, solid-contact ion-selective electrodes (SC-ISEs) with a standard deviation of E° as low as 0.3 mV for plasticized PVC ISMs and 3.5 mV for Dow 3140 silicone ISMs were obtained. Over 100 h, these SC-ISEs exhibit an emf drift of 20 µV/h for plasticized PVC ISMs and 62 µV/h for silicone ISMs. The differences in long-term stability and reproducibility between electrodes with ISMs comprising either a plasticized PVC or silicone matrix offer valuable insights into the effect of the polymeric matrix on sensor performance.

2.
Langmuir ; 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39149971

RESUMO

For ion-selective electrodes (ISEs) to be employed in wearable and implantable applications, the ion-selective membrane components should be biocompatible, and leaching of components, such as plasticizer or ionophore, out of the sensing membrane should be inhibited. To achieve this, we employed a plasticizer-free silicone as the membrane matrix and synthesized as the ionophore a derivative of the bis-crown ether based potassium ionophore BME-44, incorporating a triethoxysilyl functional group that covalently attaches to condensation-cured silicones during the curing process. Soxhlet extraction of these membranes with dichloromethane shows that up to 96% of the ionophore is attached to the silicone membrane during curing. We found that the covalently attachable BME-44 derivative can inadvertently adsorb onto high surface area carbon solid contacts before attaching to the silicone matrix if the curing of the silicone is performed in the presence of the high surface area carbon, resulting in depletion of ionophore from the membrane and yielding solid-contact ISEs with poor selectivity. In contrast, we observed Nernstian responses to K+ in plasticizer-free silicone-based K+ ISMs with either mobile BME-44 or the covalently attachable BME-44 derivative when the membranes were prepared on octane-thiol coated gold electrodes, where ionophore adsorption does not occur to a noticeable extent. As compared with ISMs doped with the mobile BME-44, ISMs prepared with the covalently attachable BME-44 derivative have better selectivity for K+ vs Na+ (log⁡KK+,Na+ values of -3.54 and <- 4.05 for mobile and covalently attachable BME-44, respectively) and lower resistance. This can be explained by a more homogeneous incorporation of the covalently attachable BME-44 derivative into the silicone matrix than is the case for the mobile BME-44.

3.
Langmuir ; 40(3): 1785-1792, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38198594

RESUMO

The use of large surface area carbon materials as transducers in solid-contact ion-selective electrodes (ISEs) has become widespread. Desirable qualities of ISEs, such as a small long-term drift, have been associated with a high capacitance that arises from the formation of an electrical double layer at the interface of the large surface area carbon material and the ion-selective membrane. The capacitive properties of these ISEs have been observed using a variety of techniques, but the effects of the ions present in the ion-selective membrane on the measured value of the capacitance have not been studied in detail. Here, it is shown that changes in the size and concentration of the ions in the ion-selective membrane as well as the polarity of the polymeric matrix result in capacitances that can vary by up to several hundred percent. These data illustrate that the interpretation of comparatively small differences in capacitance for different types of solid contacts is not meaningful unless the composition of the ion-selective membrane is taken into account.

4.
Clin Chem Lab Med ; 62(3): 551-561, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-37870269

RESUMO

OBJECTIVES: Children with congenital heart disease (CHD) undergoing cardiac surgery on cardiopulmonary bypass (CPB) are at risk for systemic inflammation leading to endothelial dysfunction associated with increased morbidity. Bioactive adrenomedullin (bio-ADM) is a peptide regulating vascular tone and endothelial permeability. The aim of this study was to evaluate the dynamics of plasma bio-ADM in this patient cohort and its role in capillary leak. METHODS: Plasma samples from 73 pediatric CHD patients were collected for bio-ADM measurement at five different timepoints (TP) in the pre-, intra-, and post-operative period. The primary endpoint was a net increase in bio-ADM levels after surgery on CPB. Secondary endpoints included association of bio-ADM levels with clinical signs for endothelial dysfunction. RESULTS: Bio-ADM levels increased after surgery on CPB from pre-operative median of 12 pg/mL (IQR [interquartile range] 12.0-14.8 pg/mL) to a maximum post-operative median of 48.8 pg/mL (IQR 34.5-69.6 pg/mL, p<0.001). Bio-ADM concentrations correlated positively with post-operative volume balance, (r=0.341; p=0.005), increased demand for vasoactive medication (duration: r=0.415; p<0.001; quantity: TP3: r=0.415, p<0.001; TP4: r=0.414, p<0.001), and hydrocortisone treatment for vasoplegia (bio-ADM median [IQR]:129.1 [55.4-139.2] pg/mL vs. 37.9 [25.2-64.6] pg/mL; p=0.034). Patients who required pleural effusion drainage revealed higher bio-ADM levels compared to those who did not (median [IQR]: 66.4 [55.4-90.9] pg/mL vs. 40.2 [28.2-57.0] pg/mL; p<0.001). CONCLUSIONS: Bio-ADM is elevated in children after cardiac surgery and higher levels correlate with clinical signs of capillary leakage. The peptide should be considered as biomarker for endothelial dysfunction and as potential therapeutic target in this indication.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Cardiopatias Congênitas , Lactente , Humanos , Criança , Adrenomedulina , Ponte Cardiopulmonar , Biomarcadores , Cardiopatias Congênitas/cirurgia
5.
Anal Chem ; 95(33): 12419-12426, 2023 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-37552138

RESUMO

Solid-contact ion-selective electrodes (SC-ISEs) in direct long-term contact with physiological samples must be biocompatible and resistant to biofouling, but most wearable SC-ISEs proposed to date contain plasticized poly(vinyl chloride) (PVC) membranes, which have poor biocompatibility. Silicones are a promising alternative to plasticized PVC because of their excellent biocompatibility, but little work has been done to study the relationship between silicone composition and ISE performance. To address this, we prepared and tested K+ SC-ISEs with colloid-imprinted mesoporous (CIM) carbon as the solid contact and three different condensation-cured silicones: a custom silicone prepared in-house (Silicone 1), a commercial silicone (Dow 3140, Silicone 2), and a commercial fluorosilicone (Dow 730, Fluorosilicone 1). SC-ISEs prepared with each of these polymers and the ionophore valinomycin and added ionic sites exhibited Nernstian responses, excellent selectivities, and signal drifts as low as 3 µV/h in 1 mM KCl solution. All ISEs maintained Nernstian response slopes and had only very slightly worsened selectivities after 41 h exposure to porcine plasma (log KK,Na values of -4.56, -4.58, and -4.49, to -4.04, -4.00, and -3.90 for Silicone 1, Silicone 2, and Fluorosilicone 1, respectively), confirming that these sensors retain the high selectivity that makes them suitable for use in physiological samples. When immersed in porcine plasma, the SC-ISEs exhibited emf drifts that were still fairly low but notably larger than when measurements were performed in pure water. Interestingly, despite the very similar structures of these matrix polymers, SC-ISEs prepared with Silicone 2 showed lower drift in porcine blood plasma (-55 µV/h, over 41 h) compared to Silicone 1 (-495 µV/h) or Fluorosilicone 1 (-297 µV/h).


Assuntos
Plastificantes , Silicones , Animais , Suínos , Eletrodos Seletivos de Íons , Água , Polímeros , Íons/química
6.
Langmuir ; 39(8): 2890-2910, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36757136

RESUMO

Over the past 25 years, the field of colloidal crystal templating of inverse opal or three-dimensionally ordered macroporous (3DOM) structures has made tremendous progress. The degree of structural control over multiple length scales, understanding of mechanical properties, and complexity of systems in which 3DOM materials are a component have increased substantially. In addition, we are now seeing applications of 3DOM materials that make use of multiple features of their architecture at the same time. This Feature Article focuses on the different properties of 3DOM materials that provide functionality, including a relatively large surface area, the interconnectedness of the pores and the resulting good accessibility of the internal surface, the nanostructured features of the walls, the structural hierarchy and periodicity, well-defined surface roughness, and relative mechanical robustness at low density. It provides representative examples that illustrate the properties of interest related to applications including energy storage and conversion systems, sensors, catalysts, sorbents, photonics, actuators, and biomedical materials or devices.

7.
Anal Chem ; 92(11): 7621-7629, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32351106

RESUMO

Numerous ion-selective and reference electrodes have been developed over the years. Following the need for point-of-care and wearable sensors, designs have transitioned recently from bulky devices with an aqueous inner filling solution to planarizable solid-contact electrodes. However, unless the polymeric sensing and reference membranes are held in place mechanically, delamination of these membranes from the underlying solid to which they adhere physically limits sensor lifetime. Even minor external mechanical stress or thermal expansion can result in membrane delamination and, thereby, device failure. To address this problem, we designed a sensing platform based on poly(ethylene terephthalate) substrates to which polyacrylate-based sensing and polymethacrylate-based reference membranes are attached covalently. Ion-selective membranes with covalently attached or freely dissolved ionophore- and ionic-liquid-doped reference membranes can be directly photopolymerized onto surface-functionalized poly(ethylene terephthalate), resulting in the formation of covalent bonds between the underlying substrate and the attached membranes. H+- and K+-selective electrodes thus prepared exhibit highly selective responses with the theoretically expected (Nernstian) response slope, and reference electrodes provide sample-independent reference potentials over a wide range of electrolyte concentrations. Even repeated mechanical stress does not result in the delamination of the sensing and reference membranes, leading to electrodes with much improved long-term performance. As demonstrated for poly(ethylene-co-cyclohexane-1,4-dimethanol terephthalate) (PETG), this approach may be expanded to a wide range of other polyester, polyamide, and polyurethane platform materials. Covalent attachment of sensing and reference membranes to an inert plastic platform material is a very promising approach to a problem that has plagued the field of ion-selective electrodes and field effect transistors for over 30 years.

8.
Langmuir ; 36(23): 6540-6549, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32434334

RESUMO

Mesoporous silica is often employed as a coating material in core-shell nanoparticles to decrease the possibility of sintering or aggregation of the core particles. In this work, we discovered a surprising morphological transformation during the sulfidation and regeneration (oxidation) of core-shell CuO@mSiO2 materials designed for H2S capture. Although CuS cores were still encapsulated within the silica shells after in situ sulfidation, hollow silica shells formed during the regeneration step as CuO leached out of the shell and aggregated into larger particles. The successful sulfidation of pristine CuO@mSiO2 was facilitated by the restraining effect of silica shells on lattice growth from CuO into CuS, and the mesopores allowed for volume expansion. The phase and morphology changes during the regeneration (oxidation) process leading to the hollow shells were investigated by X-ray diffraction and transmission electron microscopy. It was observed that the cores remained encaged during the disproportionation of CuS to Cu2S, which is the first step in the oxidation of CuS. However, voids were generated when Cu2S was oxidized and reacted with water generated from the condensation of silica. A possible mechanism for this transformation involves the outward diffusion of copper ions through the mesoporous silica, leading to the migration of core particles. This migration was further accelerated by the elevated temperature in the regeneration process and promoted by the formation of the copper sulfate hydroxide through the reaction with water. This work provides key insights into the chemical stability of such core-shell structures under the influence of diffusion-driven structural transformations.

9.
Carbon N Y ; 1432019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-39439534

RESUMO

Visualization of dispersion is a challenging and unresolved issue for high aspect ratio nanofillers, such as surface-modified graphene oxide (mGO) and carbon nanotubes, in fiber reinforced polymer (FRP) composites. Conventional metrologies to study dispersion (location, spacing, size, etc.) have proven difficult and impractical when the fibers are present, particularly at the industrially-relevant, low mass fractions of nanofillers. Here, Raman spectroscopy and imaging are exploited to investigate the dispersion of mGO in unsaturated polyester (UP) resin composites both with and without glass microfiber reinforcement. Through comparative TEM and Raman maps on the same sample area, we validate a detailed Raman methodology to detect mGO agglomerate positions, even at low loadings of < 0.1 % by mass, where the sensitivity of the mGO Raman signal is dependent on incident laser wavelength. More importantly, we expand this to FRP composites, where by a proper choice of incident wavelength to avoid glass fiber fluorescence, Raman imaging is able to identify surface (2D) and sub-surface (3D) mGO microstructures near microfibers in the inter- and intralaminar regions. This measurement technique will find significant use in the FRP composite community as a readily available method to qualitatively correlate dispersion properties to processing techniques and/or mechanical performance.

10.
J Am Chem Soc ; 140(45): 15309-15318, 2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30352506

RESUMO

Promoters are ubiquitous in industrial heterogeneous catalysts. The wider roles of promoters in accelerating catalysis and/or controlling selectivity are, however, not well understood. A model system has been developed where a heterobimetallic active site comprising an active metal (Rh) and a promoter ion (Ga) is preassembled and delivered onto a metal-organic framework (MOF) support, NU-1000. The Rh-Ga sites in NU-1000 selectively catalyze the hydrogenation of acyclic alkynes to E-alkenes. The overall stereoselectivity is complementary to the well-known Lindlar's catalyst, which generates Z-alkenes. The role of the Ga in promoting this unusual selectivity is evidenced by the lack of semihydrogenation selectivity when Ga is absent and only Rh is present in the active site.

11.
J Med Virol ; 90(10): 1559-1567, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29797570

RESUMO

Primary HIV-1 infections (PHI) with non-B subtypes are increasing in developed countries while transmission of HIV-1 harboring antiretroviral resistance-associated mutations (RAMs) remains a concern. This study assessed non-B HIV-1 subtypes and RAMs prevalence among patients with PHI in university hospitals of Marseille, Southeastern France, in 2005-2015 (11 years). HIV-1 sequences were obtained by in-house protocols from 115 patients with PHI, including 38 for the 2013-2015 period. On the basis of the phylogenetic analysis of the reverse transcriptase region, non-B subtypes were identified in 31% of these patients. They included 3 different subtypes (3A, 1C, 4F), 23 circulating recombinant forms (CRFs) (CRF02_AG, best BLAST hits being CRF 36_cpx and CRF30 in 7 and 1 cases, respectively), and 5 unclassified sequences (U). Non-B subtypes proportion increased significantly, particularly in 2011-2013 vs in 2005-2010 (P = .03). CRF02_AG viruses largely predominated in 2005-2013 whereas atypical strains more difficult to classify and undetermined recombinants emerged recently (2014-2015). The prevalence of protease, nucleos(t)ide reverse transcriptase, and first-generation nonnucleoside reverse transcriptase inhibitors-associated RAMs were 1.7% (World Health Organization [WHO] list, 2009/2.6% International AIDS Society [IAS] list, 2017), 5.2%/4.3%, and 5.2%/5.2%, respectively. Etravirine/rilpivirine-associated RAM (IAS) prevalence was 4.3%. Men who have sex with men (MSM) were more frequently infected with drug-resistant viruses than other patients (26% vs 7%; P = .011). The recent increase of these rare HIV-1 strains and the spread of drug-resistant HIV-1 among MSM in Southeastern France might be considered when implementing prevention strategies and starting therapies.


Assuntos
Farmacorresistência Viral , Genótipo , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , HIV-1/classificação , HIV-1/efeitos dos fármacos , Adulto , Fármacos Anti-HIV/farmacologia , Feminino , França/epidemiologia , HIV-1/genética , HIV-1/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Prevalência , Recombinação Genética , Análise de Sequência de DNA
12.
Inorg Chem ; 57(5): 2782-2790, 2018 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-29461822

RESUMO

Nanocasting can be a useful strategy to transfer the catalytic metal clusters in metal-organic frameworks (MOFs) to an all-inorganic support such as silica. The incorporation of silica in the MOF pores as a secondary support has the potential to extend the application of the highly tunable metal-based active sites in MOFs to high temperature catalysis. Here, we demonstrate the applicability of the nanocasting method to a range of MOFs that incorporate catalytically attractive hexazirconium, hexacerium, or pentanickel oxide-based clusters (UiO-66, (Ce)UiO-66, (Ce)UiO-67, (Ce)MOF-808, DUT-9, and In- and Ni-postmetalated NU-1000). We describe, in tutorial form, the challenges associated with nanocasting of MOFs that are related to their small pore size and to considerations of chemical and mechanical stability, and we provide approaches to overcome some of these challenges. Some of these nanocast materials feature the site-isolated clusters in a porous, thermally stable silica matrix, suitable for catalysis at high temperatures; in others, structural rearrangement of clusters or partial cluster aggregation occurs, but extensive aggregation can be mitigated by the silica skeleton introduced during nanocasting.

13.
Angew Chem Int Ed Engl ; 57(48): 15707-15711, 2018 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-30335209

RESUMO

While bottom-up syntheses of ordered nanostructured materials at colloidal length scales have been successful at producing close-packed materials, it is more challenging to synthesize non-close-packed (ncp) structures. Here, a metal oxide nanostructure with ncp hollow sphere arrays was synthesized by combining a polymeric colloidal crystal template (CCT) with a Pechini precursor. The CCT provided defined confinement through its tetrahedral (Td ) and octahedral (Oh ) voids where the three-dimensionally (3D) ordered, ncp hollow sphere arrays formed as a result of a crystallization-induced rearrangement. This nanostructure, consisting of alternating, interconnected large and small hollow spheres, is distinct from the inverse opal structures typically generated from these CCTs. The morphology of the ncp hollow sphere arrays was retained in pseudomorphic transformations involving sulfidation and reoxidation cycling despite the segregation of zinc during these steps.

14.
Nat Mater ; 20(11): 1456-1458, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34697425
15.
Faraday Discuss ; 201: 287-302, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28631795

RESUMO

NU-1000, a mesoporous metal-organic framework (MOF) featuring hexazirconium oxide nodes and 3 nm wide channels, was infiltrated with a reactive dicobalt complex to install dicobalt active sites onto the MOF nodes. The anchoring of the dicobalt complex onto NU-1000 occurred with a nearly ideal stoichiometry of one bimetallic complex per node and with the cobalt evenly distributed throughout the MOF particle. To access thermally robust multimetallic sites on an all-inorganic support, the modified NU-1000 materials containing either the dicobalt complex, or an analogous cobalt-aluminum species, were nanocast with silica. The resulting materials feature Co2 or Co-Al bimetallated hexazirconium oxide clusters within a silica matrix. The cobalt-containing materials are competent catalysts for the selective oxidation of benzyl alcohol to benzaldehyde. Catalytic activity depends on the number of cobalt ions per node, but does not vary significantly between the NU-1000 and silica supports. Hence, the multimetallic oxide clusters remain site-isolated and substrate-accessible within the nanocast materials.

16.
BMC Musculoskelet Disord ; 18(1): 276, 2017 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-28645272

RESUMO

BACKGROUND: Bone and joint infection involving Granulicatella adiacens is rare, and mainly involved in cases of bacteremia and infectious endocarditis. Here we report three cases of prosthetic joint infection involving G. adiacens that were successfully treated with surgery and prolonged antimicrobial treatment. We also review the two cases of prosthetic joint infection involving G. adiacens that are reported in the literature. CASE PRESENTATION: Not all five cases of prosthetic joint infection caused by G. adiacens were associated with bacteremia or infectious endocarditis. Dental care before the onset of infection was observed in two cases. The median time delay between arthroplasty implantation and the onset of infection was of 4 years (ranging between 2 and 10 years). One of our cases was identified with 16srRNA gene sequencing, one case with MALDI-TOF mass spectrometry, and one case with both techniques. Two literature cases were diagnosed by 16srRNA gene sequencing. All five cases were cured after surgery including a two-stage prosthesis exchange in three cases, a one-stage prosthesis exchange in one case, and debridement, antibiotics, irrigation, and retention of the prosthesis in one case, and prolonged antimicrobial treatment. CONCLUSION: Prosthetic joint infection involving G. adiacens is probably often dismissed due to difficult culture or misdiagnosis, in particular in the cases of polymicrobial infection. Debridement, antibiotics, irrigation, and retention of the prosthesis associated with prolonged antimicrobial treatment (≥ 8 weeks) should be considered as a treatment strategy for prosthetic joint infection involving G. adiacens.


Assuntos
Carnobacteriaceae/isolamento & purificação , Prótese de Quadril/efeitos adversos , Prótese do Joelho/efeitos adversos , Infecções Relacionadas à Prótese/microbiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
17.
Int Orthop ; 41(6): 1085-1091, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28405808

RESUMO

PURPOSE: Cases of fracture-fixation device infection involving Staphylococcus lugdunensis are not frequent. The clinical characteristics and the choice of treatment strategies of these infections are not obviously known to date. METHODS: We performed a review of fracture-fixation device infection involving S. lugdunensis managed by our centres. RESULTS: Among the 38 cases of fracture-fixation device infection involving S. lugdunensis, 53% were located in the tibia. Most of our cases (87%) were chronic infections. Purulent discharge, which occurred in 79% of cases, was the most frequent clinical symptom, followed by pain in 63%, local inflammation in 55%, and fever in 37%. Bacteremia and severe sepsis occurred in 10% and 18% of cases, respectively. Four cases (10%) were treated exclusively with antimicrobial treatment alone. Thirty-four cases (89%) were treated with a combination of surgery with antimicrobial therapy including surgical debridement, antibiotics and osteosynthesis device retention in six cases (16%), and osteosynthesis device removal in 27 cases (71%). The mean length of antibiotic treatment was 119 days. The relapse rate was high that was not related to selection of resistant strains. Polymicrobial infection had no impact on clinical outcome. A combination of surgery with antimicrobial therapy was identified as a significant prognostic factor associated with remission (p = 0.042). CONCLUSIONS: S. lugdunensis is probably involved in more infections than has been reported. Using appropriate microbiological methods laboratories should routinely identify the species of all coagulase-negative Staphylococci isolates involved in fracture-fixation device infection to better achieve the treatment strategies of fracture-fixation device infection involving S. lugdunensis.


Assuntos
Fixadores Internos/efeitos adversos , Infecções Relacionadas à Prótese/epidemiologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus lugdunensis , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Desbridamento , Feminino , Humanos , Fixadores Internos/microbiologia , Masculino , Pessoa de Meia-Idade , Infecções Relacionadas à Prótese/microbiologia , Infecções Relacionadas à Prótese/terapia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/cirurgia
18.
J Am Chem Soc ; 138(8): 2739-48, 2016 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-26848741

RESUMO

Metal-organic frameworks (MOFs) provide convenient systems for organizing high concentrations of single catalytic sites derived from metallic or oxo-metallic nodes. However, high-temperature processes cause agglomeration of these nodes, so that the single-site character and catalytic activity are lost. In this work, we present a simple nanocasting approach to provide a thermally stable secondary scaffold for MOF-based catalytic single sites, preventing their aggregation even after exposure to air at 600 °C. We describe the nanocasting of NU-1000, a MOF with 3 nm channels and Lewis-acidic oxozirconium clusters, with silica. By condensing tetramethylorthosilicate within the NU-1000 pores via a vapor-phase HCl treatment, a silica layer is created on the inner walls of NU-1000. This silica layer provides anchoring sites for the oxozirconium clusters in NU-1000 after the organic linkers are removed at high temperatures. Differential pair distribution functions obtained from synchrotron X-ray scattering confirmed that isolated oxozirconium clusters are maintained in the heated nanocast materials. Pyridine adsorption experiments and a glucose isomerization reaction demonstrate that the clusters remain accessible to reagents and maintain their acidic character and catalytic activity even after the nanocast materials have been heated to 500-600 °C in air. Density functional theory calculations show a correlation between the Lewis acidity of the oxozirconium clusters and their catalytic activity. The ability to produce MOF-derived materials that retain their catalytic properties after exposure to high temperatures makes nanocasting a useful technique for obtaining single-site catalysts suitable for high-temperature reactions.

20.
Intervirology ; 59(2): 118-122, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27923228

RESUMO

OBJECTIVES: Anal cancer incidence is increasing among HIV-positive patients. No consensus currently exists for the screening of anal dysplasia. This study aimed at evaluating the feasibility and acceptability of anal self-sampling and assessing the prevalence of human papillomavirus (HPV) types among HIV-positive patients from Marseille University Hospitals. METHODS: Between October 2013 and March 2014, during their regular visits for the monitoring of their HIV infection in an HIV outpatient clinical unit of Marseille University Hospitals, patients were asked to self-sample anal swabs for HPV detection. A specimen self-collection kit was provided. HPV detection and genotyping were performed using in-house protocols. The quality of self-sampling was assessed by concurrent cellular quantification in collected samples. RESULTS: The acceptability rate of anal self-sampling was 91%, and 91% of the self-sampled specimens were appropriate for HPV screening. In addition, 76% of the samples were positive for HPV, including 54% of HPV types with oncogenic potential. CONCLUSIONS: This study indicates that HPV detection and typing through anal self-sampling is a valuable strategy to screen patients at high risk for anal cancer development. This could allow earlier management of anal lesions and related cancer in patients at high risk for HPV.


Assuntos
Doenças do Ânus/diagnóstico , Neoplasias do Ânus/prevenção & controle , Infecções por HIV/complicações , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/diagnóstico , Manejo de Espécimes/métodos , Adulto , Idoso , Doenças do Ânus/complicações , Doenças do Ânus/virologia , Neoplasias do Ânus/diagnóstico , Neoplasias do Ânus/virologia , DNA Viral/isolamento & purificação , Estudos de Viabilidade , Feminino , França/epidemiologia , Genótipo , Infecções por HIV/virologia , Papillomavirus Humano 16/classificação , Papillomavirus Humano 16/isolamento & purificação , Humanos , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Ambulatório Hospitalar , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Prevalência
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