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1.
World J Surg ; 44(1): 163-170, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31583457

RESUMO

BACKGROUND: There is substantial evidence that resecting adrenal metastases can be safely accomplished and extend overall survival in select patients. However, patient access to this operation has not been studied at the population level. The purpose of this study was to determine differences in utilization rates of adrenal metastasectomy (ADMX) across patient populations. METHODS: The Healthcare Utilization Project National Inpatient Sample was used to identify patients who had adrenal metastases (ADM) and who underwent ADMX from 2007 to 2011. Patients were identified by ICD-9-CM diagnosis and procedure codes. Predictor variables included sex, race, median household income, and primary insurance payer. Primary outcomes included receiving an ADMX and same hospitalization mortality. Secondary outcomes included length of stay, infection, cardiac, pulmonary, and renal complications. Univariable and multivariable logistic regression models were used to identify statistical associations. RESULTS: 32,331 ADM and 1070 ADMX patients identified in the database. Despite similar comorbidities, Black patients had 0.30 (95% CI 0.21-0.41) lower odds to receive an ADMX compared to White patients. Medicaid patients had 0.38 (0.28-0.52) less odds and Private Insurance patients 1.18 (1.00-1.39) more odds to receive an ADMX compared to Medicare patients. Women had a 1.39 (1.22-1.58) higher odds ratio of undergoing ADMX compared to men. Of the ADMX cohort, there was no difference in same hospitalization mortality or surgical complications. CONCLUSIONS: Black and Medicaid patients underwent fewer adrenal metastasectomies despite similar comorbidities and postoperative outcomes. This suggests a potential disparity in access to this treatment that disproportionately affects Black and low-income patients, and prompts further study, outreach attempts, as well as, research into improving access.


Assuntos
Neoplasias das Glândulas Suprarrenais/secundário , Neoplasias das Glândulas Suprarrenais/cirurgia , Acessibilidade aos Serviços de Saúde , Disparidades em Assistência à Saúde , Metastasectomia , Aceitação pelo Paciente de Cuidados de Saúde , Neoplasias das Glândulas Suprarrenais/mortalidade , Negro ou Afro-Americano , Idoso , Estudos Transversais , Feminino , Disparidades em Assistência à Saúde/economia , Disparidades em Assistência à Saúde/etnologia , Mortalidade Hospitalar , Humanos , Modelos Logísticos , Masculino , Metastasectomia/mortalidade , Metastasectomia/estatística & dados numéricos , Pessoa de Meia-Idade , População Branca
2.
Chemistry ; 25(9): 2322-2329, 2019 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-30537238

RESUMO

Localized drug delivery represents one of the most challenging uses of systems based on conductive polymer films. Typically, anionic drugs are incorporated within conductive polymers through electrostatic interaction with the positively charged polymer. Following this approach, the synthetic glucocorticoid dexamethasone phosphate is often delivered from neural probes to reduce the inflammation of the surrounding tissue. In light of the recent literature on the neuroprotective and anti-inflammatory properties of tauroursodeoxycholic acid (TUDCA), for the first time, this natural bile acid was incorporated within poly(3,4-ethylenedioxythiophene) (PEDOT). The new material, PEDOT-TUDCA, efficiently promoted an electrochemically controlled delivery of the drug, while preserving optimal electrochemical properties. Moreover, the low cytotoxicity observed with viability assays, makes PEDOT-TUDCA a good candidate for prolonging the time span of chronic neural recording brain implants.


Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes , Sistemas de Liberação de Medicamentos , Polímeros , Ácido Tauroquenodesoxicólico , Materiais Biocompatíveis/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Condutividade Elétrica , Técnicas Eletroquímicas/métodos , Humanos , Polímeros/química , Ácido Tauroquenodesoxicólico/química
3.
Bioprocess Biosyst Eng ; 40(3): 431-438, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27909862

RESUMO

Polyhemoglobin produced from pure bovine hemoglobin by reaction with PEG bis(N-succynimidil succinate) as a cross-linking agent was encapsulated in gelatin and dehydrated by freeze-drying. Free carboxyhemoglobin and polyhemoglobin microcapsules were characterized by UV-Vis spectroscopy in the absorption range 450-650 nm and cyclic voltammetry in the voltage range from -0.8 to 0.6 mV to evaluate the ability to break the bond with carbon monoxide and to study the carrier's affinity for oxygen, respectively. SEM used to observe the shape of cross-linked gelatin-polyhemoglobin microparticles showed a regular distribution of globular shapes, with mean size of ~750 nm, which was ascribed to gelatin. Atomic absorption spectroscopy was also performed to detect iron presence in microparticles. Cyclic voltammetry using an Ag-AgCl electrode highlighted characteristic peaks at around -0.6 mV that were attributed to reversible oxygen bonding with iron in oxy-polyhemoglobin structure. These results suggest this technique as a powerful, direct and alternative method to evaluate the extent of hemoglobin oxygenation.


Assuntos
Cápsulas/química , Hemoglobinas/química , Oxigênio/química , Espectrofotometria Ultravioleta , Animais , Monóxido de Carbono/química , Carboxihemoglobina/química , Bovinos , Reagentes de Ligações Cruzadas/química , Eletroquímica , Eletrodos , Liofilização , Gelatina/química , Concentração de Íons de Hidrogênio , Metemoglobina/química , Microscopia Eletrônica de Varredura , Espectrofotometria Atômica
4.
J Prosthet Dent ; 117(5): 669-676, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27881324

RESUMO

STATEMENT OF PROBLEM: Both direct and indirect techniques are used for dental restorations. Which technique should be preferred or whether they are equivalent with respect to bacterial adhesion is unclear. PURPOSE: The purpose of this in vitro study was to determine the affinity of bacterial biofilm to dental restorative composite resins placed directly and indirectly. MATERIAL AND METHODS: Five direct composite resins for restorations (Venus Diamond, Adonis, Optifil, Enamel Plus HRi, Clearfil Majesty Esthetic) and 3 indirect composite resins (Gradia, Estenia, Signum) were selected. The materials were incubated in unstimulated whole saliva for 1 day. The biofilms grown were collected and their bacterial cells counted. In parallel, the composite resin surface morphology was analyzed with atomic force microscopy. Both bacterial cell count and surface topography parameters were subjected to statistical analysis (α=.05). RESULTS: Indirect composite resins showed significantly lower levels than direct composite resins for bacterial cell adhesion, (P<.001). No significant differences were observed within the direct composite resins (P>.05). However, within the indirect composite resins a significantly lower level was found for Gradia than Estenia or Signum (P<.01). A partial correlation was observed between composite resin roughness and bacterial adhesion when the second and particularly the third-order statistical moments of the composite resin height distributions were considered. CONCLUSIONS: Indirect dental restorative composite resins were found to be less prone to biofilm adhesion than direct composite resins. A correlation of bacterial adhesion to surface morphology exists that is described by kurtosis; thus, advanced data analysis is required to discover possible insights into the biologic effects of morphology.


Assuntos
Aderência Bacteriana , Biofilmes , Resinas Compostas/química , Materiais Dentários/química , Restauração Dentária Permanente/métodos , Adonis , Técnicas In Vitro , Teste de Materiais , Metacrilatos , Poliuretanos , Propriedades de Superfície
5.
Surg Endosc ; 29(12): 3477-84, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25676200

RESUMO

BACKGROUND: Natural orifice transluminal endoscopic surgery (NOTES) involves accessing the abdominal cavity via one of the body natural orifices for enabling minimally invasive surgical procedures. However, the constraints imposed by the access modality and the limited available technology make NOTES very challenging for surgeons. Tools redesign and introduction of novel surgical instruments are imperative in order to make NOTES operative in a real surgical scenario, reproducible and reliable. Robotic technology has major potential to overcome current limitations. METHODS: The robotic platform described here consists of a magnetic anchoring frame equipped with dedicated docking/undocking mechanisms to house up to three modular robots for surgical interventions. The magnetic anchoring frame guarantees the required stability for surgical tasks execution, whilst dedicated modular robots provide the platform with adequate vision, stability and manipulation capabilities. RESULTS: Platform potentialities were demonstrated in a porcine model. Assessment was organized into two consecutive experimental steps, with a hybrid testing modality. First, platform deployment, anchoring and assembly through transoral-transgastric access were demonstrated in order to assess protocol feasibility and guarantee the safe achievement of the following experimental session. Second, transabdominal deployment, anchoring, assembly and robotic module actuation were carried out. CONCLUSIONS: This study has demonstrated the feasibility of inserting an endoluminal robotic platform composed of an anchoring frame and modular robotic units into a porcine model through a natural orifice. Once inserted into the peritoneal cavity, the platform provides proper visualization from multiple orientations. For the first time, a platform with interchangeable modules has been deployed and its components have been connected, demonstrating in vivo the feasibility of intra-abdominal assembly. Furthermore, increased dexterity employing different robotic units will enhance future system capabilities.


Assuntos
Cirurgia Endoscópica por Orifício Natural/métodos , Robótica/instrumentação , Cirurgia Assistida por Computador/instrumentação , Animais , Modelos Animais , Robótica/métodos , Suínos
6.
Implant Dent ; 24(3): 248-55, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25853585

RESUMO

INTRODUCTION: The surface microstructure of dental implants affects osseointegration, which makes their accurate topographic characterization important. We defined a procedure for evaluation of implant topography before (pre-) and after (post-) in vitro implantation test in bovine bone. MATERIALS AND METHODS: The apical morphology of ten implants was analyzed in pre- and post-conditions using atomic force microscopy or 3D profilometry. We extracted four topographical parameters (two amplitude, 1 spatial, and 1 hybrid) and assessed the differences by analysis of variance. RESULTS AND DISCUSSION: The implant with coating (Spline Twist MP-1 HA) was damaged. The two implants with highest pre-amplitude parameters (Pitt Easy VTPS, TLR3815) maintained their character on testing. Pitt Easy PURETEX and OT-F1 were the only nondamaged implants whose amplitude parameters increased. The surface area underwent minor changes even when the texture changed (Tri-Vent, Pitt Easy PURETEX, Exp #1). The implants that ranked the lowest in all parameters before implantation were DT4013TI, Tri-Vent, OT-F1, and Exp #2. On testing, DT4013TI showed the highest decrease in values, whereas Tri-Vent showed the highest increase in surface area. All the experimental implants showed similar topographic properties both pre- and post-test. CONCLUSION: For most implants, no major changes occurred in surface topography on implantation. The procedure applied seems promising to evaluate the degradation of implant surface on insertion.


Assuntos
Implantes Dentários , Animais , Bovinos , Implantação Dentária Endóssea , Técnicas In Vitro , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Propriedades de Superfície
7.
J Mater Sci Mater Med ; 25(10): 2411-20, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24573456

RESUMO

We have fabricated anodic porous alumina from thin films (100/500 nm) of aluminium deposited on technological substrates of silicon/glass, and investigated the feasibility of this material as a surface for the development of analytical biosensors aiming to assess the status of living cells. To this goal, porous alumina surfaces with fixed pitch and variable pore size were analyzed for various functionalities. Gold coated (about 25 nm) alumina revealed surface enhanced Raman scattering increasing with the decrease in wall thickness, with factor up to values of approximately 10(4) with respect to the flat gold surface. Bare porous alumina was employed for micro-patterning and observation via fluorescence images of dye molecules, which demonstrated the surface capability for a drug-loading device. NIH-3T3 fibroblast cells were cultured in vitro and examined after 2 days since seeding, and no significant (P > 0.05) differences in their proliferation were observed on porous and non-porous materials. The effect on cell cultures of pore size in the range of 50-130 nm--with pore pitch of about 250 nm--showed no significant differences in cell viability and similar levels in all cases as on a control substrate. Future work will address combination of all above capabilities into a single device.


Assuntos
Óxido de Alumínio/química , Técnicas Biossensoriais , Técnicas de Cultura de Células/instrumentação , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Adesão Celular , Sobrevivência Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/química , Estudos de Viabilidade , Ouro/química , Teste de Materiais , Camundongos , Células NIH 3T3 , Nanoestruturas/química , Porosidade , Propriedades de Superfície
8.
ACS Appl Mater Interfaces ; 16(3): 3093-3105, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38206310

RESUMO

As is known, carbon nanotubes favor cell growth in vitro, although the underlying mechanisms are not yet fully elucidated. In this study, we explore the hypothesis that electrostatic fields generated at the interface between nonexcitable cells and appropriate scaffold might favor cell growth by tuning their membrane potential. We focused on primary human fibroblasts grown on electrospun polymer fibers (poly(lactic acid)─PLA) with embedded multiwall carbon nanotubes (MWCNTs). The MWCNTs were functionalized with either the p-methoxyphenyl (PhOME) or the p-acetylphenyl (PhCOMe) moiety, both of which allowed uniform dispersion in a solvent, good mixing with PLA and the consequent smooth and homogeneous electrospinning process. The inclusion of the electrically conductive MWCNTs in the insulating PLA matrix resulted in differences in the surface potential of the fibers. Both PLA and PLA/MWCNT fiber samples were found to be biocompatible. The main features of fibroblasts cultured on different substrates were characterized by scanning electron microscopy, immunocytochemistry, Rt-qPCR, and electrophysiology revealing that fibroblasts grown on PLA/MWCNT reached a healthier state as compared to pure PLA. In particular, we observed physiological spreading, attachment, and Vmem of fibroblasts on PLA/MWCNT. Interestingly, the electrical functionalization of the scaffold resulted in a more suitable extracellular environment for the correct biofunctionality of these nonexcitable cells. Finally, numerical simulations were also performed in order to understand the mechanism behind the different cell behavior when grown either on PLA or PLA/MWCNT samples. The results show a clear effect on the cell membrane potential, depending on the underlying substrate.


Assuntos
Nanotubos de Carbono , Humanos , Nanotubos de Carbono/química , Potenciais da Membrana , Poliésteres/química , Polímeros/química , Fibroblastos
9.
Materials (Basel) ; 16(3)2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36770000

RESUMO

Reanodizing metal underlayers through porous anodic alumina has already been used extensively to fabricate ordered columns of different metal oxides. Here, we present similar 3D multilayered nanostructures with unprecedented complexity. Two-level 3D column-like nanofilms have been synthesized by anodizing an Al/Nb metal layer in aqueous oxalic acid for forming the first level, and an Al/Ta layer in aqueous tartaric acid for forming the second level of the structure. Both levels were then reanodized in aqueous boric acid. The Ta layer deposited on partially dissolved porous anodic alumina of the first level, with protruding tops of niobia columns, acquired a unique hexagonally-packed structure. The morphology of the first and second levels was determined using scanning electron microscopy. Prolonged etching for 24 h in a 50%wt aqueous phosphoric acid was used to remove the porous anodic alumina. The formation mechanism of aluminum phosphates on the second-level columns in the process of long-time cold etching is considered. The model for the growth of columns on a Ta hexagonally-packed structure of the second level is proposed and described. The described approach can be applied to create 3D two- or three-level column-like systems from various valve metals (Ta, Nb, W, Hf, V, Ti), their combinations and alloys, with adjustable column sizes and scaling. The results of optical simulation show a high sensitivity of two-level column-like 3D nanofilms to biomedical objects and liquids. Among potential applications of these two-level column-like 3D nanofilms are photonic crystals for full-color displays, chemical sensors and biosensor, solar cells and thermoresponsive shape memory polymers.

10.
PLOS Glob Public Health ; 3(4): e0001758, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37186110

RESUMO

Both tuberculosis (TB) and COVID-19 can affect the respiratory system, and early findings suggest co-occurrence of these infectious diseases can result in elevated mortality. A retrospective cohort of patients who were diagnosed with TB and COVID-19 concurrently (within 120 days) between March 2020 and June 2022 in New York City (NYC) was identified. This cohort was compared with a cohort of patients diagnosed with TB-alone during the same period in terms of demographic information, clinical characteristics, and mortality. Cox proportional hazards regression was used to compare mortality between patient cohorts. One hundred and six patients with concurrent TB/COVID-19 were identified and compared with 902 patients with TB-alone. These two cohorts of patients were largely demographically and clinically similar. However, mortality was higher among patients with concurrent TB/COVID-19 in comparison to patients with TB-alone, even after controlling for age and sex (hazard ratio 2.62, 95% Confidence Interval 1.66-4.13). Nearly one in three (22/70, 31%) patients with concurrent TB/COVID-19 aged 45 and above died during the study period. These results suggest that TB patients with concurrent COVID-19 were at high risk for mortality. It is important that, as a high-risk group, patients with TB are prioritized for resources to quickly diagnose and treat COVID-19, and provided with tools and information to protect themselves from COVID-19.

11.
Adv Sci (Weinh) ; 10(10): e2205223, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36683230

RESUMO

Breast cancer cell colonization of the lungs is associated with a dismal prognosis as the distributed nature of the disease and poor permeability of the metastatic foci challenge the therapeutic efficacy of small molecules, antibodies, and nanomedicines. Taking advantage of the unique physiology of the pulmonary circulation, here, micro-combinatorial hydrogel particles (µCGP) are realized via soft lithographic techniques to enhance the specific delivery of a cocktail of cytotoxic nanoparticles to metastatic foci. By cross-linking short poly(ethylene glycol) (PEG) chains with erodible linkers within a shape-defining template, a deformable and biodegradable polymeric skeleton is realized and loaded with a variety of therapeutic and imaging agents, including docetaxel-nanoparticles. In a model of advanced breast cancer lung metastasis, µCGP amplified the colocalization of docetaxel-nanoparticles with pulmonary metastatic foci, prolonged the retention of chemotoxic molecules at the diseased site, suppressed lesion growth, and boosted survival beyond 20 weeks post nodule engraftment. The flexible design and modular architecture of µCGP would allow the efficient deployment of complex combination therapies in other vascular districts too, possibly addressing metastatic diseases of different origins.


Assuntos
Antineoplásicos , Neoplasias da Mama , Neoplasias Pulmonares , Humanos , Feminino , Docetaxel , Hidrogéis , Neoplasias da Mama/tratamento farmacológico , Antineoplásicos/uso terapêutico , Neoplasias Pulmonares/tratamento farmacológico
12.
Analyst ; 137(8): 1785-92, 2012 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-22354094

RESUMO

We propose a large-area SERS device with efficient fluorescence quenching capability. The substrate is based on anodic porous alumina templates with various pore size and wall thickness as small as 15 and 36 nm, respectively. The nano-patterned SERS substrate, with excellent control and reproducibility of plasmon-polaritons generation, shows very efficient enhanced Raman signal in the presence of intrinsically fluorescent molecules such as cresyl violet, rhodamine, and green fluorescent protein. This work demonstrates that, when the nanostructures are properly designed and fabricated, Raman and fluorescence spectroscopy can be used in combination in order to obtain complementary molecular informations. Theoretical simulation shows excellent agreement with the experimental findings. The enhancement factor is found to be 10(3)-10(4), with respect to flat gold surface when the molecules are supposed to be closely packed, with considerable fluorescence suppression, showing a promising disposable biosensor.


Assuntos
Técnicas Biossensoriais , Benzoxazinas , Corantes Fluorescentes/química , Proteínas de Fluorescência Verde/química , Oxazinas/química , Reprodutibilidade dos Testes , Rodaminas/química , Espectrometria de Fluorescência , Análise Espectral Raman
13.
Microsc Res Tech ; 85(2): 721-727, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34558750

RESUMO

Lapping and polishing are industrial processes sometimes used alternatively for surface finishing of hard and brittle materials. This article presents advanced image analysis of surfaces of quartz crystal blanks finished by lapping and polishing. Scanning electron micrographs were obtained from workpiece surfaces parallel to Y-, AT-, and Z-cut crystal planes treated with different normal stress and abrasive grit size, and stereometric and fractal/multifractal approaches were used to analyze the respective surfaces. Fractal dimensions and segmentation parameters were able to decode the effect of normal stress increasing on the surface roughness of lapped and polished samples. Moreover, the texture isotropy and the bifractal-hence agglomerated-nature of the surface patterns, suggest that both treatments dismiss the anisotropic signature of hardness and fracture toughness inherent to each crystal plane. This study provides promising results regarding the applicability of fractal analysis in the assessment of surfaces severely worn by the combined effect of brittle microcracking and plastic deformation mechanisms.

14.
JAMA Netw Open ; 5(1): e2144210, 2022 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-35050357

RESUMO

Importance: Electronic directly observed therapy (DOT) is used increasingly as an alternative to in-person DOT for monitoring tuberculosis treatment. Evidence supporting its efficacy is limited. Objective: To determine whether electronic DOT can attain a level of treatment observation as favorable as in-person DOT. Design, Setting, and Participants: This was a 2-period crossover, noninferiority trial with initial randomization to electronic or in-person DOT at the time outpatient tuberculosis treatment began. The trial enrolled 216 participants with physician-suspected or bacteriologically confirmed tuberculosis from July 2017 to October 2019 in 4 clinics operated by the New York City Health Department. Data analysis was conducted between March 2020 and April 2021. Interventions: Participants were asked to complete 20 medication doses using 1 DOT method, then switched methods for another 20 doses. With in-person therapy, participants chose clinic or community-based DOT; with electronic DOT, participants chose live video-conferencing or recorded videos. Main Outcomes and Measures: Difference between the percentage of medication doses participants were observed to completely ingest with in-person DOT and with electronic DOT. Noninferiority was demonstrated if the upper 95% confidence limit of the difference was 10% or less. We estimated the percentage of completed doses using a logistic mixed effects model, run in 4 modes: modified intention-to-treat, per-protocol, per-protocol with 85% or more of doses conforming to the randomization assignment, and empirical. Confidence intervals were estimated by bootstrapping (with 1000 replicates). Results: There were 173 participants in each crossover period (median age, 40 years [range, 16-86 years]; 140 [66%] men; 80 [37%] Asian and Pacific Islander, 43 [20%] Black, and 71 [33%] Hispanic individuals) evaluated with the model in the modified intention-to-treat analytic mode. The percentage of completed doses with in-person DOT was 87.2% (95% CI, 84.6%-89.9%) vs 89.8% (95% CI, 87.5%-92.1%) with electronic DOT. The percentage difference was -2.6% (95% CI, -4.8% to -0.3%), consistent with a conclusion of noninferiority. The 3 other analytic modes yielded equivalent conclusions, with percentage differences ranging from -4.9% to -1.9%. Conclusions and Relevance: In this trial, the percentage of completed doses under electronic DOT was noninferior to that under in-person DOT. This trial provides evidence supporting the efficacy of this digital adherence technology, and for the inclusion of electronic DOT in the standard of care. Trial Registration: ClinicalTrials.gov Identifier: NCT03266003.


Assuntos
Antituberculosos/uso terapêutico , Terapia Diretamente Observada , Telemedicina/métodos , Cooperação e Adesão ao Tratamento/estatística & dados numéricos , Tuberculose Pulmonar/tratamento farmacológico , Humanos , Cidade de Nova Iorque , Resultado do Tratamento , Tuberculose/tratamento farmacológico , Comunicação por Videoconferência/estatística & dados numéricos
15.
Materials (Basel) ; 15(21)2022 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-36363016

RESUMO

Iron niobates, pure and substituted with copper (Fe1-xCuxNbO4 with x = 0-0.15), were prepared by the solid-state method and characterized by X-ray diffraction, Raman spectroscopy, and magnetic measurements. The results of the structural characterizations revealed the high solubility of Cu ions in the structure and better structural stability compared to the pure sample. The analysis of the magnetic properties showed that the antiferromagnetic-ferromagnetic transition was caused by the insertion of Cu2+ ions into the FeNbO4 structure. The pure FeNbO4 structure presented an antiferromagnetic ordering state, with a Néel temperature of approximately 36.81K. The increase in substitution promoted a change in the magnetic ordering, with the state passing to a weak ferromagnetic order with a transition temperature (Tc) higher than the ambient temperature. The origin of the ferromagnetic ordering could be attributed to the increase in super-exchange interactions between Fe/Cu ions in the Cu2+-O-Fe3+ chains and the formation of bound magnetic polarons in the oxygen vacancies.

16.
Materials (Basel) ; 15(21)2022 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-36363134

RESUMO

Poly(3-hydroxybutyrate) (PHB)-based films containing Poly(ethylene glycol) (PEG), esterified sodium alginate (ALG-e) and polymeric additives loaded with Ag nanoparticles (AgNPs) were obtained by a conventional casting method. AgNPs were produced in aqueous suspension and added to polymeric gels using a phase exchange technique. Composite formation was confirmed by finding the Ag peak in the XRD pattern of PHB. The morphological analysis showed that the inclusion of PEG polymer caused the occurrence of pores over the film surface, which were overshadowed by the addition of ALG-e polymer. The PHB functional groups were dominating the FTIR spectrum, whose bands associated with the crystalline and amorphous regions increased after the addition of PEG and ALG-e polymers. Thermal analysis of the films revealed a decrease in the degradation temperature of PHB containing PEG/AgNPs and PEG/ALG-e/AgNPs, suggesting a catalytic effect. The PHB/PEG/ALG-e/AgNPs film combined the best properties of water vapor permeability and hydrophilicity of the different polymers used. All samples showed good antimicrobial activity in vitro, with the greater inhibitory halo observed for the PEG/PEG/AgNPs against Gram positive S. aureus microorganisms. Thus, the PHB/PEG/ALG-e/AgNPs composite demonstrated here is a promising candidate for skin wound healing treatment.

17.
Materials (Basel) ; 15(20)2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36295339

RESUMO

Molecularly imprinted membrane of ß-caryophyllene (MIM-ßCP) was fabricated incorporating ß-caryophyllene molecularly imprinted polymer nanoparticles (ßCP-NP) into polycaprolactone (PCL) fibers via electrospinning. The ßCP-NP were synthesized by precipitation polymerization using the ßCP as a template molecule and acrylic acid as a functional monomer in the proportion of 1:4 mol, respectively. Atomic force microscopy images and X-ray diffraction confirmed the nanoparticles' incorporation into MIM-ßCP. MIM-ßCP functionalization was evaluated by gas chromatography. The binding capacity was 1.80 ± 0.05 µmol/cm2, and the selectivity test was performed with a mixing solution of ßCP and caryophyllene oxide, as an analog compound, that extracted 77% of the ßCP in 5 min. The electrospun MIM-ßCP can be used to detect and extract the ßCP, applications in the molecular sieve, and biosensor production and may also contribute as an initial methodology to enhance versatile applications in the future, such as in the treatment of skin diseases, filters for extraction, and detection of ßCP to prevent counterfeiting of commercial products, and smart clothing with insect-repellent properties.

18.
Nanoscale Horiz ; 8(1): 95-107, 2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36426604

RESUMO

Over the last few years it has been understood that the interface between living cells and the underlying materials can be a powerful tool to manipulate cell functions. In this study, we explore the hypothesis that the electrical cell/material interface can regulate the differentiation of cancer stem-like cells (CSCs). Electrospun polymer fibres, either polyamide 66 or poly(lactic acid), with embedded graphene nanoplatelets (GnPs), have been fabricated as CSC scaffolds, providing both the 3D microenvironment and a suitable electrical environment favorable for CSCs adhesion, growth and differentiation. We have investigated the impact of these scaffolds on the morphological, immunostaining and electrophysiological properties of CSCs extracted from human glioblastoma multiform (GBM) tumor cell line. Our data provide evidence in favor of the ability of GnP-incorporating scaffolds to promote CSC differentiation to the glial phenotype. Numerical simulations support the hypothesis that the electrical interface promotes the hyperpolarization of the cell membrane potential, thus triggering the CSC differentiation. We propose that the electrical cell/material interface can regulate endogenous bioelectrical cues, through the membrane potential manipulation, resulting in the differentiation of CSCs. Material-induced differentiation of stem cells and particularly of CSCs, can open new horizons in tissue engineering and new approaches to cancer treatment, especially GBM.


Assuntos
Glioblastoma , Humanos , Eletricidade Estática , Engenharia Tecidual/métodos , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Diferenciação Celular , Microambiente Tumoral
19.
Materials (Basel) ; 14(24)2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34947086

RESUMO

Magnetron-sputtered thin films of titanium and zirconium, with a thickness of 150 nm, were hydrogenated at atmospheric pressure and a temperature of 703 K, then anodized in boric, oxalic, and tartaric acid aqueous solutions, in potentiostatic, galvanostatic, potentiodynamic, and combined modes. A study of the thickness distribution of the elements in fully anodized hydrogenated zirconium samples, using Auger electron spectroscopy, indicates the formation of zirconia. The voltage- and current-time responses of hydrogenated titanium anodizing were investigated. In this work, fundamental possibility and some process features of anodizing hydrogenated metals were demonstrated. In the case of potentiodynamic anodizing at 0.6 M tartaric acid, the increase in titanium hydrogenation time, from 30 to 90 min, leads to a decrease in the charge of the oxidizing hydrogenated metal at an anodic voltage sweep rate of 0.2 V·s-1. An anodic voltage sweep rate in the range of 0.05-0.5 V·s-1, with a hydrogenation time of 60 min, increases the anodizing efficiency (charge reduction for the complete oxidation of the hydrogenated metal). The detected radical differences in the time responses and decreased efficiency of the anodic process during the anodizing of the hydrogenated thin films, compared to pure metals, are explained by the presence of hydrogen in the composition of the samples and the increased contribution of side processes, due to the possible features of the formed oxide morphologies.

20.
Materials (Basel) ; 14(4)2021 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33562047

RESUMO

The volumetric growth, composition, and morphology of porous alumina films fabricated by reduced temperature 280 K galvanostatic anodizing of aluminum foil in 0.4, 1.0, and 2.0 M aqueous sulfuric acid with 0.5-10 mA·cm-2 current densities were investigated. It appeared that an increase in the solution concentration from 0.4 to 2 M has no significant effect on the anodizing rate, but leads to an increase in the porous alumina film growth. The volumetric growth coefficient increases from 1.26 to 1.67 with increasing current density from 0.5 to 10 mA·cm-2 and decreases with increasing solution concentration from 0.4 to 2.0 M. In addition, in the anodized samples, metallic aluminum phases are identified, and a tendency towards a decrease in the aluminum content with an increase in solution concentration is observed. Anodizing at 0.5 mA·cm-2 in 2.0 M sulfuric acid leads to formation of a non-typical nanostructured porous alumina film, consisting of ordered hemispheres containing radially diverging pores.

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