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1.
J Prosthet Dent ; 125(4): 693.e1-693.e7, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33431178

RESUMO

STATEMENT OF PROBLEM: Nonthermal argon plasma (NTAP) has been reported to improve the bond strength of resin cements to yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics. However, the effect of the inevitable delay before cementation and after treating Y-TZP ceramics with NTAP is unclear. PURPOSE: The purpose of this in vitro study was to investigate whether delays of 8, 12, and 24 hours between the Y-TZP ceramic treatment with NTAP and the cementation would affect the surface energy and the bond strength of a self-adhesive resin cement to Y-TZP ceramic. MATERIAL AND METHODS: Sixty plates and 50 blocks of 3Y-TZP ceramic were divided into 2 groups (n=30 and n=25): as-sintered (AS) and airborne-particle abraded with 50-µm Al2O3 (APA). These groups were further divided into 5 subgroups (n=6 and n=5) according to the delay between the NTAP treatment and the measurement of surface energy and microtensile bond strength (µTBS) evaluation: (0, 8, 12, and 24 hours). For both 3Y-TZP surface conditions (AS and APA), a control group without NTAP treatment was used (ASC and APAC). The surface energy (SE) was evaluated with a goniometer and the 3Y-TZP elemental composition with X-ray photoelectron spectroscopy (XPS). For the µTBS test, the 3Y-TZP ceramic blocks were cemented to composite resin blocks with a self-adhesive resin cement. After storage in distilled water at 37 °C for 24 hours, the 3Y-TZP-composite resin blocks were sectioned into beams and submitted to a µTBS test. Data were submitted to 2-way ANOVA and the Tukey HSD test (α=.05). RESULTS: For the AS group, NTAP increased the SE irrespective of the delay before measurement: ASC<0 hour=8 hours=12 hours=24 hours (P<.05). For the APA group, except after 12 hours, NTAP also increased the surface energy (P<.05). XPS analysis showed an increase in the oxygen/carbon ratio after NTAP treatment for both groups. For the AS group, NTAP increased the µTBS after 0, 8, and 12 hours (P<.05), whereas for the APA group this occurred only after 8 hours (P<.05). For the AS and APA groups, the highest µTBS was reached after 8 hours (P<.05). CONCLUSIONS: Treatment of 3Y-TZP ceramic with NTAP improved the SE and increased the µTBS of self-adhesive resin cement to 3Y-TZP ceramic. These effects were time dependent, with better results at 8 hours after NTAP treatment.


Assuntos
Colagem Dentária , Gases em Plasma , Argônio , Cimentação , Cerâmica , Cimentos Dentários , Análise do Estresse Dentário , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Ítrio , Zircônio
2.
Food Chem ; 346: 128974, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33465571

RESUMO

The effects of argon and nitrogen cold plasma treatments on the lipolytic enzymes activity in wheat germ were investigated. Using argon as plasma gas, the residual activity of lipase and lipoxygenase decreased to 42.50% and 87.72%, respectively after 30 min. Switching plasma input gas to nitrogen, the residual activities of lipase and lipoxygenase after the same time of atmospheric cold plasma (ACP) treatment were 77.50% and 92.52%, respectively. The antioxidant potential and phenolic compounds show no significant difference during ACP duration. However, the remaining activities of lipase and lipoxygenase after 30 min steam autoclaving were 6.25% and 18.60%, respectively. Also, the antioxidant activity and total phenolic content reduced by 14.70% and 30.80%, respectively. In brief, the ACP treatment efficiency was function of the input gas and the treatment time. The presented results about the input gas impacts would be useful in industrial development of ACP application for wheat germ stabilization.


Assuntos
Lipase/metabolismo , Lipoxigenase/metabolismo , Gases em Plasma/química , Triticum/enzimologia , Antioxidantes/química , Argônio/química , Nitrogênio/química , Fenóis/química , Temperatura , Triticum/química
3.
Molecules ; 26(3)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499107

RESUMO

This paper presents the results of an investigation into the photooxidation of tocopherols (Tocs) dissolved in argonated and non-argonated n-hexane. During irradiation, steady-state absorption and fluorescence spectra as well as lifetimes were measured. In all experiments, the photoreactions were of the first order type. The reaction rate was higher for all Tocs in argonated solvent. A new emission band with a maximum at 298 nm as well as new absorption and fluorescence bands beyond the 300 nm connected with charge-transfer (C-T) complexes for all Tocs appeared during the irradiation of γ- and δ-Toc. The above results indicate that the photooxidation process is very complex and that the observed phenomena strongly depend on the number and position of methyl groups in the chromanol ring.


Assuntos
Hexanos/química , Tocoferóis/química , Tocoferóis/efeitos da radiação , Argônio/química , Dimerização , Depuradores de Radicais Livres/química , Oxirredução , Processos Fotoquímicos , Solventes , Espectrometria de Fluorescência , Espectrofotometria , Estereoisomerismo , Raios Ultravioleta
4.
Arch Biochem Biophys ; 698: 108726, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33326801

RESUMO

The study investigates the effect of LPDBD (Low Pressure Dielectric Barrier Discharge) (Ar + Air) plasma on seed germination, seedling growth and antioxidant enzyme activity of rice. Rice seeds were treated with LPDBD (Ar + Air) plasma for 2min, 4min, 6min, 8min and 10min. Seed germination rate, seedling growth, total chlorophyll content, enzymatic activity, total soluble sugar and protein concentration were increased in plants grown from the LPDBD (Ar + Air) plasma treated seeds. It was observed that the sprouting of seeds and the growth of seedlings of rice depends on the feed gases used to generate plasma and plasma processing time. In the case of plantlets germinated from the plasma-treated seeds of rice, the H2O2 level was increased significantly both in leaves and roots for 6min, 8min and 10min treatment respectively. No significant change was observed in Nitric Oxide (NO) concentration in seed, leaf, or root of plants grown from LPDBD (Ar + Air) plasma-treated seeds. The amount of total soluble sugar and protein increased significantly in the case of 2min, 4min, 6min, 8min and 10min seed treatment. Although plants exhibited no significant increase in APX activities, but a significant increase of CAT and SOD activity in the leaf and root was found. This study reveals that LPDBD (Ar + Air) plasma is involved in the elevation of ROS species in leaf and root of rice plants which is tightly regulated by the upregulation of CAT activity that ultimately enhances the seed germination and growth of rice plantlets.


Assuntos
Catalase/metabolismo , Oryza/metabolismo , Gases em Plasma/farmacologia , Plântula/metabolismo , Sementes/metabolismo , Superóxido Dismutase/metabolismo , Ar , Argônio/química , Germinação/efeitos dos fármacos , Germinação/fisiologia , Oryza/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento
5.
J Environ Radioact ; 228: 106513, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33360017

RESUMO

While radioisotopes of noble gases are known to be indicators of underground nuclear explosions (UNE), McIntyre et al. (2017) was the first to report the presence of 39Ar in shallow soil gas in association with a decades old UNE. While this finding hinted at the potential application of 39Ar to be used as an indicator of a UNE, doing so would also require an understanding of the natural concentrations of 39Ar present in soil gas. Without knowing the expected range and variability of naturally occurring concentrations of 39Ar, it is difficult to determine what measured concentrations would be indicative of an elevated concentration. This paper presents results from 16 soil gas samples and three atmospheric air samples collected from various locations across the western United States. Shallow soil gas samples were collected into self-contained underwater breathing apparatus (SCUBA) tanks using a custom-built soil gas sampling system and then processed and analyzed for 39Ar. The measured concentrations of 39Ar varied from atmospheric air concentrations to about 3.5 times atmospheric air concentrations (58 mBq/m3). The results presented here represent the first measurements of natural background 39Ar concentrations in shallow soil gas. This data will be necessary if 39Ar is to be used as an indicator of UNE.


Assuntos
Argônio , Radiação de Fundo , Monitoramento de Radiação , Radioisótopos , Poluentes Radioativos do Solo/análise , Argônio/análise , Radioisótopos/análise , Solo
6.
Anticancer Res ; 40(11): 6205-6212, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33109557

RESUMO

BACKGROUND/AIM: Mammary carcinoma (MC) remains one of the leading causes of morbidity and mortality in the female population worldwide. Cold physical plasma at atmospheric pressure (CAP) has an antioncogenic effect on tumor cells, and its anticancer properties may complement or even extend existing treatment options. In the present study, the efficacy of CAP was characterized on an MC in vitro cell culture system. MATERIALS AND METHODS: MC cells (MCF-7, MDA-MB-231) were directly treated with CAP or incubated with CAP-treated cell culture medium. Cell growth, cell mobility and apoptosis were subsequently analyzed. RESULTS: A single treatment of MC cells with CAP and CAP treated medium led to a treatment-time dependent reduction of cell growth. Furthermore, CAP exposure led to a loss of cellular motility and induced apoptosis. CONCLUSION: Due to its anticancer properties, CAP treatment is an innovative and promising physical approach to expand and complement the treatment options for MC. In particular, a combination of CAP application with surgical and/or chemotherapeutic interventions might significantly improve the therapeutic outcomes.


Assuntos
Argônio/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Gases em Plasma/uso terapêutico , Argônio/farmacologia , Pressão Atmosférica , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Cinética , Gases em Plasma/farmacologia
7.
Int J Food Microbiol ; 335: 108892, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-32979616

RESUMO

Cold plasma is a novel technology for surface decontamination. Almond slices can be contaminated with different microorganisms during their production. In the current research, the atmospheric argon plasma treatment (5, 10, 15, and 20 min) was used to decontamination of almond slices surface. Microbial load, Color, peroxide value, hardness, and sensory properties of slices was comprised with untreated samples (control). Descriptive sensory evaluation about color, flavor, crispiness, crunchiness, and hardness of almond slices were performed. According to the results of the microbial tests, Total count, molds and yeasts, and Staphylococcus aureus of almond surface decreased about 2.95 log cfu/g, 1.81 log cfu/g, and 2.72 log cfu/g after 20 min of plasma treatment, respectively, provided that microbial reduction increased more by increasing the treatment time. Coupled with the color evaluation, peroxide value and sensory attributes didn't change during plasma treatment. Having said that, the hardness of slices was changed by increasing treatment time. Furthermore, Principal Component Analysis and cluster analysis were performed for sensory evaluation. In light of the consumer's point of view, firstly 10 min and secondly 15 min plasma treatment can be more desirable.


Assuntos
Argônio/farmacologia , Descontaminação/métodos , Qualidade dos Alimentos , Gases em Plasma/farmacologia , Prunus dulcis/microbiologia , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Humanos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
8.
Niger J Clin Pract ; 23(9): 1266-1273, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32913167

RESUMO

Aims: This study evaluated the effect of oxygen plasma and argon plasma treatments with different application times on tensile bonding of a silicone-based denture liner to polymethylmetacrylate (PMMA). Methods: Seven groups (n = 5) were prepared and six of them treated by argon plasma or oxygen plasma with 30s, 60s, and 120s, respectively; one group was left untreated served as control. After processing of denture liner, the specimens were deflasked and stored dry for 24 h, and they were then subjected to tensile bond strength testing. Differences in tensile bond strength values were determined using one-way ANOVA (α = 0.05). Results: Highest tensile bond strengths were observed in the oxygen plasma groups, followed by untreated group and argon plasma groups in turn in order. Tensile bond strenght were increased with time for both type of plasma applications tested. Conclusion: This study suggests that the adhesion between PMMA and denture liner is improved under conditions of oxygen plasma treatment with extended exposure time rather than argon plasma treatment.


Assuntos
Coagulação com Plasma de Argônio , Colagem Dentária/métodos , Reembasadores de Dentadura , Polimetil Metacrilato/química , Silicones/química , Resistência à Tração , Argônio , Bases de Dentadura , Humanos , Teste de Materiais , Oxigênio , Propriedades de Superfície
9.
Int J Oral Maxillofac Implants ; 35(4): 731-738, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32724924

RESUMO

PURPOSE: To evaluate the influence of bioactivation with argon plasma of a xenograft used as graft material for sinus floor augmentation. MATERIALS AND METHODS: Sinus floor elevation was performed in 20 rabbits using a deproteinized bovine bone mineral as graft material. The xenograft used in the test sites was bioactivated with argon plasma (plasma group), while that used in the control sites was left untreated (control group). Collagen membranes were used to cover the antrostomy. The rabbits were euthanized after 2 and 10 weeks, in groups of 10 each. A histomorphometric analysis was performed in various regions of the elevated space. RESULTS: After 2 weeks of healing, a similar pattern of healing was observed in both groups. New bone fractions were 5.2% ± 2.9% in the plasma group and 5.0% ± 3.5% in the control group (P = .795). In this period, higher amounts of new bone were found in the region close to the sinus bone walls. After 10 weeks of healing, the amounts of new bone within the elevated space increased to 23.5% ± 7.0% and 21.3% ± 7.3% (P = .176) in the plasma and control groups, respectively. The only statistically significant difference was found in the central region, with 20.4% ± 9.7% in the plasma group and 13.2% ± 10.5% in the control group (P = .037). CONCLUSION: The bioactivation of a xenograft using argon plasma improved bone formation within an augmented sinus, especially in the central regions, far from osteogenic sources.


Assuntos
Substitutos Ósseos , Gases em Plasma , Levantamento do Assoalho do Seio Maxilar , Animais , Argônio , Matriz Óssea , Transplante Ósseo , Bovinos , Seio Maxilar , Minerais , Coelhos
10.
Proc Natl Acad Sci U S A ; 117(29): 17063-17067, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32631997

RESUMO

Little is known about the exchange of gaseous nitrogen (N2) with the atmosphere in freshwater systems. Although the exchange of N2, driven by excess or deficiencies relative to saturation values, has little relevance to the atmospheric N2 pool due to its large size, it does play an important role in freshwater and marine nitrogen (N) cycling. N-fixation converts N2 to ammonia, which can be used by microbes and phytoplankton, while denitrification/anammox effectively removes it by converting oxidized, inorganic N to N2 We examined N2 saturation to infer net biological nitrogen processes in 34 lakes across 5° latitude varying in trophic status, mixing regime, and bathymetry. Here, we report that nearly all lakes examined in the upper Midwest (USA) were supersaturated with N2 (>85% of samples, n = 248), suggesting lakes are continuously releasing nitrogen to the atmosphere. The traditional paradigm is that freshwaters compensate for N-limitation through N-fixation, but these results indicate that lakes were constantly losing N to the atmosphere via denitrification and/or anammox, suggesting that terrestrial N inputs are needed to balance the internal N cycle.


Assuntos
Lagos , Nitrogênio/análise , Argônio/análise , Gases de Efeito Estufa/análise , Lagos/análise , Lagos/química , Minnesota , Fixação de Nitrogênio , Oxigênio/análise
11.
J Chromatogr A ; 1625: 461302, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709345

RESUMO

Additives are added to polymers in small concentration to achieve desired application properties widely used to tailor the properties. The rapid diversification of their molecular structures, with often only minute differences, necessitates the development of adequate chromatographic techniques. While modified silica so far is the workhorse as stationary phase we have probed the potential of porous graphitic carbon (HypercarbTM) for this purpose. The results show that the multitude of physicochemical interactions between analyte molecules and the graphitic surface enables separations of polyolefin stabilizers with unprecedented selectivity. To support the chromatographic results the adsorption capability of HypercarbTM for selected antioxidants and UV absorbers has been determined by Raman spectroscopy and argon physisorption measurements. The shift of the Graphite-band in the Raman spectra of HypercarbTM upon infusion with additives correlates with the changes in the Adsorption Potential Distributions. The results of argon physisorption measurements go hand in hand with the chronology of desorption of the additives in liquid chromatography experiments. The elution sequence can be explained by van der Waals or London forces, π-π-interactions and electron lone pair donor-acceptor interactions between the graphite surface and analyte functional groups.


Assuntos
Grafite/química , Polímeros/química , Análise Espectral Raman , Adsorção , Antioxidantes/isolamento & purificação , Argônio/química , Clorofórmio/química , Éteres Metílicos/química , Polienos/química , Porosidade , Fatores de Tempo
12.
Int J Food Microbiol ; 324: 108612, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32244103

RESUMO

Effect of in-bag dielectric barrier discharge cold plasma (IB-DBD-CP) on the keeping quality of Asian sea bass slices (ASBS) packaged under different gases during refrigerated storage at 4 °C was studied. ASBS without and with IB-DBD-CP treatment packaged under the gas combination of argon and oxygen (10:90) (gas A) or the mixtures of carbon dioxide, argon and oxygen (60:30:10) (gas B) and the control (kept in air) were monitored for quality changes up to 18 days. ASBS treated with IB-DBD-CP, regardless of gas composition, had lower microbial loads than those without treatment and the control (p < 0.05). The shelf-life of ASBS was prolonged to 9 and 12 days after being packaged under gas A and B, respectively without IB-DBD-CP treatment, while 6 days were recorded for the control. However, ASBS treated with IB-DBD-CP, packaged under gas A and B had the shelf-life of 12 and 15 days, respectively. Throughout the storage, trimethylamine content and total volatile nitrogen base content were lower in ASBS treated with IB-DBD-CP, particularly those packaged under gas B than that without treatment and the control (p < 0.05). Nevertheless, lipid oxidation as well as protein oxidation were higher in samples treated with IB-DBD-CP, regardless of gas composition used, in comparison with untreated counterpart. Therefore, IB-DBD-CP of ASBS packaged under high ratio of CO2 (60%) along with argon and oxygen was the potential method for augmenting the shelf-life of ASBS for >15 days at 4 °C.


Assuntos
Bass , Conservação de Alimentos/métodos , Armazenamento de Alimentos/métodos , Gases em Plasma/química , Alimentos Marinhos/análise , Animais , Argônio/análise , Bass/microbiologia , Dióxido de Carbono/análise , Qualidade dos Alimentos , Oxigênio/análise , Alimentos Marinhos/microbiologia
14.
Photosynth Res ; 143(3): 275-286, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31897856

RESUMO

The aim of this work was a comparative study of S-repleted and S-depleted photoautotrophic cultures of Chlamydomonas reinhardtii under aerobic and anoxic conditions with the main focus on PSII activity. For that we used photobioreactor with short light path connected on-line to PAM fluorometer and cultivated microalgae in twice concentrated HS medium to avoid any uncontrolled limitation by mineral elements. Photoautotrophic cultures grown under Ar + CO2 gas mixture did not reach the same Chl (a + b) concentration as control culture (grown under air + CO2). At pO2 40% of air saturation (96 µM O2), the actual quantum yield of PSII started to decrease. Under microaerobic conditions when cultures stopped growing, the most significant changes in PSII function were observed. Maximum quantum yield Fv/Fm decreased significantly along with performance index, PIabs. It was accompanied by increase of fluorescence at J point, Vj. Results indicate that microaerobic conditions are stressful for photoautotrophic cultures. Photoautotrophic cultures of microalgae under S-deprivation in aerobic or anaerobic conditions showed similar behavior as photoheterotrophic ones described earlier. However, photoautotrophic cultures during anaerobiosis establishment did not show sharp "switch off" effect of actual quantum yield. We show also that S-deprivation under air or argon as well as the growth under Ar + CO2 cause significant increase of initial rise of fluorescence, which indicates that PSII and oxygen-evolving complex might be disintegrated.


Assuntos
Processos Autotróficos , Chlamydomonas reinhardtii/metabolismo , Hidrogênio/metabolismo , Processos Fototróficos , Enxofre/deficiência , Anaerobiose/efeitos dos fármacos , Argônio/farmacologia , Atmosfera , Processos Autotróficos/efeitos dos fármacos , Técnicas de Cultura Celular por Lotes , Dióxido de Carbono/farmacologia , Chlamydomonas reinhardtii/efeitos dos fármacos , Chlamydomonas reinhardtii/crescimento & desenvolvimento , Fluorometria , Oxigênio/metabolismo , Fotobiorreatores/microbiologia , Processos Fototróficos/efeitos dos fármacos
16.
J Vasc Interv Radiol ; 31(3): 393-400.e1, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31987705

RESUMO

PURPOSE: To evaluate the efficacy and safety of percutaneous argon-helium cryoablation (CA) for hepatocellular carcinoma (HCC) abutting the diaphragm (<5 mm). MATERIALS AND METHODS: A total of 61 consecutive patients (50 men, 11 women; mean age, 56.3 ± 12.1 years old; range, 32-83 years) with 74 HCC tumors (mean size, 3.3 ± 1.7 cm; range, 0.8-7 cm) who were treated with percutaneous argon-helium CA were enrolled in this retrospective study. Adverse events were evaluated according to Common Terminology Criteria for Adverse Events, version 5.0. Local tumor progression (LTP) and overall survival (OS) were analyzed using the Kaplan-Meier method and the log-rank test. The risk factors associated with OS and LTP were evaluated using univariate and multivariate Cox regression analysis. RESULTS: No periprocedural (30-day) deaths occurred. A total of 29 intrathoracic adverse events occurred in 24 of the 61 patients. Major adverse events were reported in 5 patients (pleural effusion requiring catheter drainage in 4 patients and pneumothorax requiring catheter placement in 1 patient). Median follow-up was 18.7 months (range, 2.3-60.0 months). Median time to LTP after CA was 20.9 months (interquartile range [IQR], 14.1-30.6 months). Median times of OS after CA and diagnosis were 27.3 months (IQR, 15.1-45.1 months) and 40.9 months (interquartile range, 24.8-68.6 months), respectively. Independent prognostic factors for OS included tumor location (left lobe vs right lobe; hazard ratio [HR], 2.031; 95% confidence interval [CI], 1.062-3.885; P = .032) and number of intrahepatic tumors (solitary vs multifocal; HR, 2.684; 95% CI, 1.322-5.447; P = .006). Independent prognostic factors for LTP included age (HR, 0.931; 95% CI, 0.900-0.963; P  < .001), guidance modality (ultrasound vs computed tomography and US; HR, 6.156 95% CI, 1.862-20.348; P  =   .003) and origin of liver disease. CONCLUSIONS: Percutaneous argon-helium CA is safe for the treatment of HCC abutting the diaphragm, with acceptable LTP and OS.


Assuntos
Argônio/uso terapêutico , Carcinoma Hepatocelular/cirurgia , Criocirurgia , Hélio/uso terapêutico , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Argônio/efeitos adversos , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/patologia , Criocirurgia/efeitos adversos , Criocirurgia/mortalidade , Diafragma , Progressão da Doença , Feminino , Hélio/efeitos adversos , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/terapia , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Carga Tumoral
17.
Pak J Biol Sci ; 23(3): 248-256, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31944085

RESUMO

BACKGROUND AND OBJECTIVE: Atmospheric pressure plasma jet (APPJ) gained great interest due to its effectiveness as selective non-lethal technique with low operational costs. In this study, argon APPJ system was designed and the generated cold plasma was applied in disinfection of microbial cells. MATERIALS AND METHODS: Argon APPJ was generated by blowing argon through capillary metallic tube inserted in alumina and powered by 8-25 kHz sinusoidal voltage waveform. The plasma applied in inactivation of microbes by direct exposure of cell suspension, approximately 10 mm below jet nozzle, for different intervals. Interference of organics in exposure medium, on lethal activity of plasma was investigated. RESULTS: APPJ jet induced high levels of reactive oxygen (ROS) and nitrogen species (RNS). Jet length increased with applied voltage and flow rate in laminar mode, but decreased with flow rate in turbulent mode. Percent reduction in living cell count was 98.3 and 94.1%, for E. coli and S. aureus suspended in water after 30s of exposure, respectively, with 2.7- and 2-folds increase in plasma lethal activity, as compared with LB broth medium. D-values (Decimal Reduction Time) were increased from 34-333, 37-476 and 139-385 s for E. coli, S. aureus and C. albicans in water and complex liquid organic media, respectively. CONCLUSION: Designed argon APPJ system can be used in disinfection of different microbes. Plasma antimicrobial activity drastically decreased in presence of organic matter. The generated plasma can be promising approach for treatment of diseases, especially caused by antibiotic-resistant pathogens.


Assuntos
Argônio/química , Desinfecção/métodos , Gases em Plasma , Anti-Infecciosos/química , Pressão Atmosférica , Candida albicans/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Radicais Livres , Viabilidade Microbiana , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacos
18.
Clin Oral Investig ; 24(8): 2611-2623, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31748982

RESUMO

BACKGROUND: The osteoconductive properties of bone grafting materials represent one area of research for the management of bony defects found in the fields of periodontology and oral surgery. From a physico-chemical aspect, the wettability of the graft has been demonstrated to be one of the most important factors for new bone formation. It is also well-known that argon plasma treatment (PAT) and ultraviolet irradiation (UV) may increase the surface wettability and, consequently, improve the regenerative potential of the bone grafts. Therefore, the aim of the present in vitro study was to evaluate the effect of PAT and UV treatment on the osteoconductive potential of various bone grafts. MATERIALS AND METHODS: The following four frequently used bone grafts were selected for this study: synthetic hydroxyapatite (Mg-HA), biphasic calcium phosphate (BCP), cancellous and cortical xenogenic bone matrices (CaBM, CoBM). Sixty-six serially numbered disks 10 mm in diameter were used for each graft material and randomly assigned to the following three groups: test 1 (PAT), test 2 (UV), and control (no treatment). Six samples underwent topographic analysis using SEM pre- and post-treatments to evaluate changes in surface topography/characteristics. Additionally, cell adhesion and cell proliferation were evaluated at 2 and 72 h respectively following incubation in a three-dimensional culture system utilizing a bioreactor. Furthermore, the effects of PAT and UV on immune cells were assessed by measuring the viability of human macrophages at 24 h. RESULTS: The topographic analysis showed different initial morphologies of the commercial biomaterials (e.g., Mg-HA and BCP showed flat morphology; BM samples were extremely porous with high roughness). The surface analysis following experimental treatments did not demonstrate topographical difference when compared with controls. Investigation of cells demonstrated that PAT treatment significantly increased cell adhesion of all 4 evaluated bone substitutes, whereas UV failed to show any statistically significant differences. The viability test revealed no differences in terms of macrophage adhesion on any of the tested surfaces. CONCLUSION: Within their limitations, the present results suggest that treatment of various bone grafting materials with PAT appears to enhance the osteoconductivity of bone substitutes in the early stage by improving osteoblast adhesion without concomitantly affecting macrophage viability. CLINICAL RELEVANCE: Treatment of bone grafts with PAT appears to result in faster osseointegration of the bone grafting materials and may thus favorably influence bone regeneration.


Assuntos
Regeneração Óssea , Substitutos Ósseos , Argônio , Materiais Biocompatíveis , Transplante Ósseo , Durapatita , Humanos , Gases em Plasma
19.
Ecotoxicol Environ Saf ; 189: 110015, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31830602

RESUMO

This paper adopts a novel data-processing method of ECSA® based on TG/DSC-MS system to basically study the characteristics of release and conversion of fluorides and cyanides during heat treatment of the spent cathode carbon block (SCCB). All the experiments were conducted at 10 K⋅min-1 heating rate and under Ar or Ar-O2 atmospheres. The results indicate that the release of fluorides was just a steady but slow phase transition process under both Ar and Ar-O2 atmospheres, which can be comparatively accelerated when the carbon material was burnt. The cyanides were effectively decomposed at high temperature and at Ar-O2 atmosphere, with around three quarters of the cyanides being converted to the N2 and nearly a quarter being to the NO. Finally, analysis on the flue gas composition indicates that it had a more complicated composition of CO2, N2, NO, NO2, HCN under Ar-O2 atmosphere but only had a composition of CO2 and NO under Ar atmosphere.


Assuntos
Poluentes Atmosféricos/química , Carbono/química , Cianetos/química , Eletrodos , Fluoretos/química , Poluentes Atmosféricos/análise , Alumínio , Argônio/química , Atmosfera/química , Cianetos/análise , Fluoretos/análise , Temperatura Alta , Metalurgia , Eliminação de Resíduos
20.
Int J Biol Macromol ; 142: 769-777, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31622703

RESUMO

In this research, the influence of different cold plasma treatments was investigated as a novel method for modification of protein film properties. The films were prepared from whey and gluten proteins using solvent casting method and then treated with vacuum low-pressure glow plasma using air and argon gases at 50 KW for 5, 10, and 15 min and further analyzed mechanically and physicochemically. The images of atomic force microscopy (AFM) revealed a significant increase in roughness of whey protein films after plasma treatment, while the roughness of treated gluten films diminished dramatically. Furthermore, the tensile strength of films improved significantly after 10 min of process, from 6.902 to 10.772 MPa and from 1.854 to 2.571 MPa for whey protein and gluten films, respectively. Introduction of functional groups such as CO and OC bonds plus cross link creation was observed by FTIR which could lead to changes in different film features. Although gas permeability of both edible polymers decreased significantly, other parameters including solubility and water vapor permeability of control and plasma treated (PT) films did not show dramatic differences. Therefore, the optimum condition and time of low-pressure glow plasma has the potential for modifying protein films.


Assuntos
Glutens/química , Gases em Plasma/química , Proteínas do Soro do Leite/química , Ar , Argônio/química , Membranas Artificiais , Permeabilidade , Polimerização , Solubilidade , Vapor , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , Vácuo
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