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1.
Chemistry ; 28(22): e202200254, 2022 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-35254708

RESUMO

Graphene doped with heteroatoms such as nitrogen, boron, and phosphorous by replacing some of the skeletal carbon atoms is emerging as an important class of two-dimensional materials as it offers the much-needed bandgap for optoelectronic applications and provides better access for chemical functionalization at the heteroatom sites. Covalent grafting of photosensitizers onto such doped graphenes makes them extremely useful for light-induced applications. Herein, we report the covalent functionalization of N-doped graphene (NG) with two well-known electron donor photosensitizers, namely, zinc porphyrin (ZnP) and zinc phthalocyanine (ZnPc), using the simple click chemistry approach. Covalent attachment of ZnP and ZnPc at the N-sites of NG in NG-ZnP and NG-ZnPc hybrids was confirmed by using a range of spectroscopic, thermogravimetric and imaging techniques. Ground- and excited-state interactions in NG-ZnP and NG-ZnPc were monitored by using spectral and electrochemical techniques. Efficient quenching of photosensitizer fluorescence in these hybrids was observed, and the relatively easier oxidations of ZnP and ZnPc supported excited-state charge-separation events. Photoinduced charge separation in NG-ZnP and NG-ZnPc hybrids was confirmed by using the ultrafast pump-probe technique. The measured rate constants were of the order of 1010  s,-1 thus indicating ultrafast electron transfer phenomena.

2.
Small ; 17(25): e2101483, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33988903

RESUMO

Nanotechnology can offer a number of options against coronavirus disease 2019 (COVID-19) acting both extracellularly and intracellularly to the host cells. Here, the aim is to explore graphene oxide (GO), the most studied 2D nanomaterial in biomedical applications, as a nanoscale platform for interaction with SARS-CoV-2. Molecular docking analyses of GO sheets on interaction with three different structures: SARS-CoV-2 viral spike (open state - 6VYB or closed state - 6VXX), ACE2 (1R42), and the ACE2-bound spike complex (6M0J) are performed. GO shows high affinity for the surface of all three structures (6M0J, 6VYB and 6VXX). When binding affinities and involved bonding types are compared, GO interacts more strongly with the spike or ACE2, compared to 6M0J. Infection experiments using infectious viral particles from four different clades as classified by Global Initiative on Sharing all Influenza Data (GISAID), are performed for validation purposes. Thin, biological-grade GO nanoscale (few hundred nanometers in lateral dimension) sheets are able to significantly reduce copies for three different viral clades. This data has demonstrated that GO sheets have the capacity to interact with SARS-CoV-2 surface components and disrupt infectivity even in the presence of any mutations on the viral spike. GO nanosheets are proposed to be further explored as a nanoscale platform for development of antiviral strategies against COVID-19.


Assuntos
COVID-19 , Glicoproteína da Espícula de Coronavírus , Grafite , Humanos , Proteínas de Membrana , Simulação de Acoplamento Molecular , Ligação Proteica , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/metabolismo
3.
Adv Healthc Mater ; 12(3): e2201968, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36300643

RESUMO

Graphene-based 2D nanomaterials possess unique physicochemical characteristics which can be utilized in various biomedical applications, including the transport and presentation of chemotherapeutic agents. In glioblastoma multiforme (GBM), intratumorally administered thin graphene oxide (GO) nanosheets demonstrate a widespread distribution throughout the tumor volume without impact on tumor growth, nor spread into normal brain tissue. Such intratumoral localization and distribution can offer multiple opportunities for treatment and modulation of the GBM microenvironment. Here, the kinetics of GO nanosheet distribution in orthotopic GBM mouse models is described and a novel nano-chemotherapeutic approach utilizing thin GO sheets as platforms to non-covalently complex a proteasome inhibitor, bortezomib (BTZ), is rationally designed. Through the characterization of the GO:BTZ complexes, a high loading capacity of the small molecule on the GO surface with sustained BTZ biological activity in vitro is demonstrated. In vivo, a single low-volume intratumoral administration of GO:BTZ complex shows an enhanced cytotoxic effect compared to free drug in two orthotopic GBM mouse models. This study provides evidence of the potential that thin and small GO sheets hold as flat nanoscale platforms for GBM treatment by increasing the bioavailable drug concentration locally, leading to an enhanced therapeutic effect.


Assuntos
Antineoplásicos , Glioblastoma , Grafite , Animais , Camundongos , Bortezomib/uso terapêutico , Glioblastoma/patologia , Grafite/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Microambiente Tumoral
4.
F1000Res ; 12: 1367, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38882713

RESUMO

Background: Salmonella enterica are bacteria that include more than 2,500 serovars. Most of these serovars have been linked to human foodborne illnesses, mainly related to poultry and pigs. Thus, these animals are considered the reservoirs of many Salmonella serovars and strains related to antibiotic resistance. This study aimed to determine the prevalence, serovars, ß-lactam resistance genes, and the risk factors associated with Salmonella enterica in pork commercialized in open markets of Quito city. Methods: For this, 165 pork meat samples were taken from municipal markets in three areas in the city. These samples were microbiologically processed following the ISO 6579-2014 standardized method. The polymerase chain reaction (PCR) test was used to identify Salmonella serotyping and resistance genes. Strains not identified by PCR were typed by the Kauffman White Le Minor scheme. A multivariate analysis was performed to identify risk factors associated with the presence of the microorganism. Results: Salmonella prevalence in pork was 9.1%. Identified serovars were 4, [5], 12: i:- (53.3%), Infantis (33.3%), and Derby (13.4%). Furthermore, the ß-lactam resistance genes bla CTX-M-65 could be identified in three S. infantis isolates. Multivariate analysis showed that temperature (above 8°C) and cutting surfaces (wood) presented significant association values. Conclusions: In conclusion, pork in traditional markets of Quito is contaminated with Salmonella enterica, whose main serovars pose a public health concern, and shows beta-lactam resistance.

5.
Int Urol Nephrol ; 55(7): 1799-1809, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36753015

RESUMO

PURPOSE: We evaluated the renal arterial resistive index (RRI), urine monocyte chemotactic protein 1 (uMCP-1), and urine neutrophil gelatinase-associated lipocalin (uNGAL) to predict acute kidney injury (AKI) in critically ill cancer patients. METHODS: In this prospective study, we included patients without AKI. We compared the area under the curve (AUC) of RRI, uMCP-1, and uNGAL to predict any stage of AKI and stage-3 AKI with the DeLong method, and we established cutoff points with the Youden index. RESULTS: We included 64 patients, and 43 (67.2%) developed AKI. The AUC to predict AKI were: 0.714 (95% CI 0.587-0.820) for the RRI, 0.656 (95% CI 0.526-0.770) for uMCP-1, and 0.677 (95% CI 0.549-0.789) for uNGAL. The AUC to predict stage-3 AKI were: 0.740 (95% CI 0.615-0.842) for the RRI, 0.757 (95% CI 0.633-0.855) for uMCP-1, and 0.817 (95% CI 0.701-0.903) for uNGAL, without statistical differences among them. For stage 3 AKI prediction, the sensitivity and specificity were: 56.3% and 87.5% for a RRI > 0.705; 70% and 79.2% for an uMCP-1 > 2169 ng/mL; and 87.5% and 70.8% for a uNGAL > 200 ng/mL. The RRI was significantly correlated to age (r = 0.280), estimated glomerular filtration rate (r = - 0.259), mean arterial pressure (r = - 0.357), and serum lactate (r = 0.276). CONCLUSION: The RRI, uMCP-1, and uNGAL have a similar ability to predict AKI. The RRI is more specific, while urine biomarkers are more sensitive to predict stage 3 AKI. The RRI correlates with hemodynamic variables. The novel uMCP-1 could be a useful biomarker that needs to be extensively studied.


Assuntos
Injúria Renal Aguda , Neoplasias , Humanos , Injúria Renal Aguda/diagnóstico , Biomarcadores , Quimiocina CCL2 , Estado Terminal , Lipocalina-2 , Estudos Prospectivos
6.
Chest ; 162(2): 375-384, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35305969

RESUMO

BACKGROUND: Interstitial lung disease (ILD) results in profound symptom burden and carries high mortality. Palliative care (PC) is dedicated to improving quality of life in patients with serious illness. Early PC provision improves rates of advance care planning and symptom management in patients with ILD. RESEARCH QUESTION: What are the current perspectives on PC among ILD providers, and what are the barriers to PC in ILD specialty centers? STUDY DESIGN AND METHODS: A 24-question electronic survey was disseminated to providers at the 68 Pulmonary Fibrosis Foundation Care Centers across the United States from October 2020 to December 2020. RESULTS: The survey was completed by 128 participants representing all 68 Pulmonary Fibrosis Foundation Care Center Network sites. Most respondents were physicians. Most providers exhibit good knowledge of, feel comfortable assessing a patient's readiness for, and agree with the need for PC for patients with ILD. Providers are most likely to refer to PC at objective disease and/or symptomatic progression rather than at initial diagnosis. In comparison with providers who report referring their patients to PC, providers who report rare referral are more likely to cite lack local PC availability (P < .01) and less likely to feel comfortable discussing prognosis/disease trajectory (P = .03) or feel it is important to address advance directives in ILD clinic (P = .02). There is a lack of standardized measures used to assess specific symptoms, overall symptom burden, or health-related quality of life across institutions. Discordance exists between self-reported and actual access to local inpatient and outpatient PC services. INTERPRETATION: Most ILD providers use PC and are comfortable discussing PC. Barriers to PC identified in this survey include the following: perceived lack of local access to PC, lack of systematic tools to assess symptom burden, lack of established optimal timing of PC referral, and unclear need for specialized PC delivery.


Assuntos
Enfermagem de Cuidados Paliativos na Terminalidade da Vida , Doenças Pulmonares Intersticiais , Fibrose Pulmonar , Humanos , Doenças Pulmonares Intersticiais/terapia , Cuidados Paliativos/métodos , Qualidade de Vida , Estados Unidos
7.
Antibiotics (Basel) ; 11(2)2022 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-35203800

RESUMO

The inappropriate use of antibiotics leads to antibiotic resistance, which reduces their efficacy. The education of undergraduates is likely to influence their practices. Assessing awareness is critical in the general effort to confront the spread of antibiotic resistance. This cross-sectional investigation was carried out using the questionnaire "Antibiotic resistance: Multi-country public awareness" developed by the World Health Organization. Students from different backgrounds at the Central University participated in the study (n = 733). The survey comprised five sections: demographics, knowledge, usage, sources of information, and attitudes. The rate of correct answers was 64.88%; differences were detected between programs of study (p < 0.001); effect size analysis showed that these differences cannot be considered large. Individuals from applied sciences scored higher than their counterparts from social studies. Mostly, interviewees were knowledgeable about usage, but mistakenly associated antibiotics with conditions such as cold/flu or viral illnesses; also, they associated antibiotic resistance with the patient and not with bacteria. Despite these misconceptions, positive attitudes were registered overall, and students generally adhered to common practices. They cited doctors/nurses and teachers as sources of information. As a consequence, it is recommended to develop courses that address deficient knowledge regarding antibiotic resistance, especially for individuals affiliated to social disciplines.

8.
Int J Technol Assess Health Care ; 27(1): 50-4, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21262067

RESUMO

OBJECTIVES: The objective of this exploratory study was to survey international health technology assessment (HTA) professionals to determine attitudes toward ethics in HTA. METHODS: An exploratory, quantitative, cross-sectional study design was developed. The sample population (n = 636) was selected from authors of the 206 articles published in the International Journal of Technology Assessment in Health Care between 2005 and 2007. A survey instrument was piloted and e-mailed. RESULTS: The response rate was low (n = 104; 16.4 percent). Respondents were primarily middle-aged (46 ± 11 years) male (62 percent) health professionals from Western countries (n = 92; 88.5 percent), with a mean of 10 (± 6 years) years of HTA experience. Although at least 90 percent of respondents agreed that healthcare decisions involved value judgments and that ethical analysis was important to HTA, respondents were divided as to whether normative (n = 45; 44.6 percent) or descriptive (n = 38; 37.6 percent) ethical recommendations were necessary. Most respondents (n = 83; 81.4 percent) believed that HTA should include citizen participation, but two thirds (n = 67; 67.0 percent) agreed that the final decision should be restricted to decision makers. A majority of respondents thought that ethical analysis could be discussed anywhere within the HTA process, either by an expert trained in ethics (n = 62; 60.8 percent) or by an external consultant (n = 80; 78.4 percent). CONCLUSIONS: This study showed that ethical discourse in HTA is constrained by practical considerations, which serves to limit moral inquiry. To increase ethical analysis, a positive attitude toward ethics needs to be fostered within the HTA community.


Assuntos
Atitude , Internacionalidade , Avaliação da Tecnologia Biomédica/ética , Adulto , Estudos Transversais , Coleta de Dados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Nanoscale ; 12(17): 9890-9898, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32347282

RESUMO

The ability of a triplet photosensitizer to generate long-lived charge separated states, in contrast to traditionally used singlet photosensitizers, in covalently functionalized single-walled carbon nanotube hybrids has been investigated. Enriched single-walled carbon nanotubes with two diameters, namely (6,5) and (7,6), were covalently modified to carry a charge-stabilizing triplet photosensitizer derived from a palladium porphyrin. The nanohybrids were fully characterized and the presence of intramolecular interactions between the porphyrin and nanotubes was established from various spectroscopic, imaging, electrochemical and thermochemical studies. Photoluminescence of palladium porphyrin was found to be quantitatively quenched in the presence of covalently appended SWCNTs and this quenching is due to excited state charge separation and has been established by femtosecond transient absorption studies. Owing to the presence of the triplet photosensitizer, the charge separated states lasted over 3 ns, i.e., much longer than those reported earlier for singlet photosensitizer-derived nanotube hybrids. The nanohybrids also exhibited efficient photocatalytic behavior in experiments involving electron pooling of one-electron reduced methyl viologen in the presence of a sacrificial electron donor. Higher yields of photoproducts were achieved from the present donor-acceptor nanohybrids when compared with those of singlet photosensitizer-derived nanohybrids, more so for (6,5) nanotube derived hybrids compared to (7,6) nanotube derived hybrids. The present findings highlight the importance of triplet photosensitizer derived nanohybrids in artificial photosynthesis of charge separation and photocatalytic applicatons.

10.
Int J Technol Assess Health Care ; 25(4): 570-6, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19845988

RESUMO

OBJECTIVES: Health Technology Assessment (HTA) is a relatively new concept in Latin America (LA). The objectives of this exploratory study were to identify HTA programs in LA, review HTA documents produced by those programs, and assess the extent to which HTA aims are being achieved. METHODS: An electronic search through two databases was performed to identify HTA programs in LA. A content analysis was performed on HTA documents (n = 236) produced by six programs between January 2000 and March 2007. Results were analyzed by comparing document content with the main goals of HTA. RESULTS: The number of HTA documents increased incrementally during the study period. The documents produced were mostly short HTA documents (82 percent) that assessed technologies such as drugs (31 percent), diagnostic and/or screening technologies (18 percent), or medical procedures (18 percent). Two-thirds (66 percent) of all HTA documents addressed issues related to clinical effectiveness and economic evaluations. Ethical, social, and/or legal issues were rarely addressed (<1 percent). The two groups most often targeted for dissemination of HTA information were third-party payers (55 percent) or government policy makers (41 percent). CONCLUSIONS: This study showed that while HTA programs in LA have attempted to address the main goals of HTA, they have done so through the production of short documents that focus on practical high-technology areas of importance to two specific target groups. Clinical and economic considerations still take precedence over ethical, social, and/or legal issues. Thus, an integrated conceptual framework in LA is wanting.


Assuntos
Avaliação da Tecnologia Biomédica/organização & administração , Pesquisa Comparativa da Efetividade , Análise Custo-Benefício , Humanos , América Latina , Avaliação de Resultados em Cuidados de Saúde/organização & administração , Avaliação da Tecnologia Biomédica/normas
11.
Nanoscale ; 11(32): 14978-14992, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31372604

RESUMO

In recent years there has been a growing interest in finding materials revealing bidirectional charge-transfer characteristics, that is, materials behaving as an electron donor or an acceptor in the presence of redox and photoactive addends, for optoelectronic applications. In this respect, carbon-based nanostructures, such as graphene and carbon nanotubes, have emerged as promising nanomaterials for the development of hybrid systems for bidirectional charge transfer, whose behaviour can be switched from donor-type to acceptor-type by simply changing the electroactive counterpart to which they are anchored. In this review we provide an overview of the main advances that have been made over the past few years in carbon-based hybrid architectures involving different types of carbon nanostructures and photosensitizers. In particular, carbon nanotube and graphene-based hybrid systems will be highlighted.

12.
Nanoscale Adv ; 1(10): 4009-4015, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-36132123

RESUMO

Hetero-atom doped graphene is a two-dimensional material with a band gap, needed to build optoelectronic devices. However, research progress in this area has been sluggish due to synthetic challenges to build energy harvesting materials, especially donor-acceptor type hybrids. In the present study, using click chemistry, we have successfully synthesized a donor-acceptor hybrid comprised of N-doped graphene and perylenediimide (PDI), a well-known electron-accepting photosensitizer. The TGA and XPS results revealed the attachment of the PDI moiety in the hybrid. Ground and excited state interactions were monitored by a variety of spectral and electrochemical techniques. Finally, the ability of the present donor-acceptor hybrid to undergo photoinduced charge separation from singlet excited PDI was systematically probed using femtosecond transient spectral techniques. Evidence of charge separation was possible to achieve from comparison of transient and spectroelectrochemical results. These results suggest the potential use of covalently functionalized, substitutional N-doped graphene as a functional material for building optoelectronic devices.

13.
Chem Commun (Camb) ; 55(67): 9999-10002, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31372622

RESUMO

Covalent B-functionalization of B-doped graphene has been performed for the first time. The electronic properties and Hall effect of functionalized N- and B-doped graphene can be tuned by tailoring the electron-donating/-withdrawing properties of the organic addend.

14.
Nanoscale ; 10(31): 15078-15089, 2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-30059118

RESUMO

Chemical functionalization of nanotubes, in which their properties can be combined with those of other classes of materials, is fundamental to improve the physicochemical properties of nanotubes for potential technological applications. In this work, we theoretically and experimentally examine the Pauson-Khand reaction (PKR) on zig-zag, armchair, and chiral single-walled carbon nanotubes (SWCNTs). Our benchmarked density functional theory (DFT) calculations show that an alternative pathway to the widely accepted Magnus reaction pathway has significantly lower energy barriers, thus suggesting the use of this alternative pathway to predict whether a PKR on SWCNTs is favored or hampered. Accessible energy barriers of up to 16 kcal mol-1 are estimated and our results suggest that semiconducting SWCNTs react faster than metallic ones, although both types can be functionalized. Guided by our theoretical predictions, cyclopentenones are successfully attached to SWCNTs by heating and are, subsequently, characterized in the laboratory.

15.
Nanoscale ; 10(11): 5205-5213, 2018 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-29493701

RESUMO

Enriched semiconducting single-walled carbon nanotubes (SWCNT (6,5) and SWCNT (7,6)) and HiPco nanotubes were covalently functionalized with either zinc phthalocyanine or silicon phthalocyanine as electron donors. The synthetic strategy resulted in edge-on and face-on geometries with respect to the phthalocyanine geometry, with both phthalocyanines held by an electronically conducting diphenylacetylene linker. The extent of functionalization in the MPc-SWCNT (M = Zn or Si) donor-acceptor nanohybrids was determined by systematic studies involving AFM, TGA, XPS, optical and Raman techniques. Intramolecular interactions in MPc-SWCNT nanohybrids were probed by studies involving optical absorbance, Raman, luminescence and electrochemical studies. Different degrees of interactions were observed depending on the type of MPc and mode of attachment. Substantial quenching of MPc fluorescence in these hybrids was observed from steady-state and three-dimensional fluorescence mapping, which suggests the occurrence of excited state events. Evidence for the occurrence of excited state charge transfer type interactions was subsequently secured from femtosecond transient absorption studies covering both the visible and near-infrared regions. Furthermore, electron-pooling experiments performed in the presence of a sacrificial electron donor and a second electron acceptor revealed accumulation of one-electron reduced product upon continuous irradiation of the nanohybrids. In such experiments, the ZnPc-SWCNT (6,5) nanohybrid outperformed other nanohybrids and this suggests that this is a superior donor-acceptor system for photocatalytic applications.

16.
Chem Sci ; 9(43): 8221-8227, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30542570

RESUMO

N-Doped graphene (N-G) was chemically functionalized by N-alkylation with the well-known electron acceptor C60. The degree of functionalization and the key structural features of the N-G/C60 hybrid were systematically investigated by a number of techniques including thermogravimetric analysis, X-ray photoelectron and Raman spectroscopies and transmission electron and atomic force microscopies. Absorption and electrochemical studies revealed interactions between the N-G and C60 while the fluorescence of C60 within the hybrid was found to be fully quenched. Evidence for the occurrence of excited state charge transfer from the singlet excited C60 to N-G in the hybrid was obtained from femtosecond transient absorption studies covering the visible-near-IR regions. Electron-pooling experiments performed in the presence of a sacrificial electron donor and a second electron acceptor, methyl viologen, revealed the accumulation of the one-electron reduced product of methyl viologen upon continuous irradiation of the N-G/C60 nanohybrid, thus revealing the utility of this material in photocatalytic energy harvesting applications.

17.
Biosens Bioelectron ; 98: 240-247, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28688310

RESUMO

Viologen-SWCNT hybrids are synthesized by aryl-diazonium chemistry in the presence of isoamyl nitrite followed by condensation reaction of the resulting HOOC-Phe-SWCNT with 1-(3-aminoethyl)-4,4'-bipyridinium bromine and N-alkylation with 2-bromoethylamine. The V-Phe-SWCNT hybrids were characterized by using different spectroscopic techniques (FT-IR, Raman, UV-vis), TGA and Kaiser test. Viologen-SWCNTs were used for the preparation of an electrochemical immunosensor for the determination of the transforming growth factor ß1 (TGF-ß1) cytokine considered as a reliable biomarker in several human diseases. The methodology involved preparation of V-Phe-SWCNT(-HRP)-anti-TGF conjugates by covalent linkage of HRP and anti-TGF onto V-Phe-SWCNT hybrids. Biotinylated anti-TGF antibodies were immobilized onto 4-carboxyphenyl-functionalized SPCEs modified with streptavidin and a sandwich type immunoassay was implemented for TGF-ß1 with signal amplification using V-Phe-SWCNT(-HRP)-anti-TGF conjugates as carrier tags. The analytical characteristics exhibited by the as prepared immunosensor (range of linearity between 2.5 and 1000pgmL-1 TGF-ß1; detection limit of 0.95pgmL-1) improve notably those reported with other previous immunosensors or ELISA kits. A great selectivity against other proteins was also found. The prepared immunosensor was validated by determining TGF-ß1 in real saliva samples. Minimal sample treatment was required and the obtained results were in excellent agreement with those obtained by using a commercial ELISA kit.


Assuntos
Técnicas Biossensoriais , Imunoensaio , Fator de Crescimento Transformador beta1/isolamento & purificação , Técnicas Eletroquímicas , Humanos , Nanotubos de Carbono/química , Fator de Crescimento Transformador beta1/química , Fator de Crescimento Transformador beta1/genética
18.
Nanoscale ; 9(22): 7551-7558, 2017 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-28534917

RESUMO

Functionalization of single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs) with a charge stabilizing zinc porphyrin functionalized with triphenylamine entities has been accomplished. The synthetic approach involved the reaction of tris-(triphenylamine)porphyrinato zinc(ii) with iodobenzene functionalized nanotubes through a Sonogashira C-C cross coupling reaction under microwave irradiation conditions. Evidence of covalent functionalization and the extent of functionalization was obtained from systematic studies carried out by AFM, TGA, XPS and Raman spectroscopy techniques. The porphyrin-nanotube interactions in the SWCNT-porphyrin hybrid were probed by studies involving optical absorbance, Raman spectroscopy, steady-state and time resolved emission and electrochemical studies. The fluorescence of porphyrin in this hybrid was found to be quenched due to interactions with the CNTs. Femtosecond transient absorption spectral studies covering both the visible and near-infrared regions were supportive of excited state charge transfer interactions in the zinc porphyrin-SWCNT. The charge separated state was persistent for about 1 ns. Electron pooling experiments suggested that this donor-acceptor nanohybrid could be a useful photocatalyst.

19.
Biosens Bioelectron ; 74: 24-9, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26093125

RESUMO

An electrochemical immunosensor for adiponectin (APN) using screen printed carbon electrodes (SPCEs) modified with functionalized double-walled carbon nanotubes (DWCNTs) as platforms for immobilization of the specific antibodies is reported. DWCNTs were functionalized by treatment with 4-aminobenzoic acid (HOOC-Phe) in the presence of isoamylnitrite resulting in the formation of 4-carboxyphenyl-DWCNTs. The oriented binding of specific antibodies toward adiponectin was accomplished by using the metallic-complex chelating polymer Mix&Go™. The HOOC-Phe-DWCNTs-modified SPCEs were characterized by cyclic voltammetry and compared with HOOC-Phe-SWCNTs/SPCE. The different variables affecting the performance of the developed immunosensor were optimized. Under the selected conditions, a calibration plot for APN was constructed showing a range of linearity extending between 0.05 and 10.0 µg/mL which is adequate for the determination of the cytokine in real samples. A detection limit of 14.5 ng/mL was achieved. The so prepared immunosensor exhibited a good reproducibility for the APN measurements, excellent storage stability and selectivity, and a much shorter assay time than the available ELISA kits. The usefulness of the immunosensor for the analysis of real samples was demonstrated by analyzing human serum from female or male healthy patients.


Assuntos
Adiponectina/sangue , Anticorpos Imobilizados/química , Técnicas Biossensoriais/instrumentação , Quelantes/química , Técnicas Eletroquímicas/instrumentação , Nanotubos de Carbono/química , Ácido 4-Aminobenzoico/química , Adiponectina/análise , Ensaio de Imunoadsorção Enzimática , Desenho de Equipamento , Feminino , Humanos , Imunoensaio/instrumentação , Limite de Detecção , Masculino , Nanotubos de Carbono/ultraestrutura , Polímeros/química , Reprodutibilidade dos Testes
20.
Med. interna Méx ; 35(2): 298-301, mar.-abr. 2019. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1135177

RESUMO

Resumen: El término asma/EPOC, denominado SOAE (sobreposición asma/EPOC), incluye a un subconjunto de pacientes con persistencia y limitación del flujo aéreo con características clínicas de asma y de EPOC. La falta de consenso de una definición de sobreposición asma/EPOC ha llevado a la amplia gama en prevalencia que varía entre 11 y 56% en la EPOC, 13 y 61% en el asma y 2% entre la población general. Los estudios iniciales han demostrado que omalizumab puede ser útil en pacientes con sobreposición asma/EPOC porque ha demostrado aliviar los síntomas, reducir las exacerbaciones y la hospitalización, así como mejorar los parámetros de función pulmonar y disminuir el requerimiento de esteroides en estos pacientes. Este artículo describe el efecto de omalizumab en cinco pacientes con diagnóstico de síndrome de sobreposición asma/EPOC y administración de omalizumab. Se describe la experiencia de nuestro centro y los beneficios que el tratamiento ha dado a nuestros pacientes, que han permitido mejor calidad de vida y disminuir de manera radical su morbilidad.


Abstract The term asthma/COPD, called SOAE (overlap asthma/EPOC acronym in English ACOS [asthma COPD overlap syndrome]), includes a subset of patients with persistence and airflow limitation that presents clinical features of both asthma and COPD. Lack of consensus on a definition of ACOS has led to the wide range in prevalence ranging between 11 and 56% in COPD, 13 and 61% in asthma, and 2% in the general population. The initial studies have shown that omalizumab may be useful in patients with ACOS, it has been shown to improve symptoms, reduce exacerbations and hospitalization, as well as improve lung function parameters and reduce steroid requirement in these patients. This paper describes the effect of omalizumab in 5 patients with a diagnosis of overlying asthma/COPD syndrome (SOAE) and administration of omalizumab. We describe the experience of our center and the benefits that the treatment has given to our patients. These benefits have allowed the patient a better quality of life and radically reduce their morbidity.

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