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1.
J Phys Chem B ; 128(14): 3383-3397, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38563384

RESUMO

Dehaloperoxidase (DHP) is a multifunctional hemeprotein with a functional switch generally regulated by the chemical class of the substrate. Its two isoforms, DHP-A and DHP-B, differ by only five amino acids and have an almost identical protein fold. However, the catalytic efficiency of DHP-B for oxidation by a peroxidase mechanism ranges from 2- to 6-fold greater than that of DHP-A depending on the conditions. X-ray crystallography has shown that many substrates and ligands have nearly identical binding in the two isoenzymes, suggesting that the difference in catalytic efficiency could be due to differences in the conformational dynamics. We compared the backbone dynamics of the DHP isoenzymes at pH 7 through heteronuclear relaxation dynamics at 11.75, 16.45, and 19.97 T in combination with four 300 ns MD simulations. While the overall dynamics of the isoenzymes are similar, there are specific local differences in functional regions of each protein. In DHP-A, Phe35 undergoes a slow chemical exchange between two conformational states likely coupled to a swinging motion of Tyr34. Moreover, Asn37 undergoes fast chemical exchange in DHP-A. Given that Phe35 and Asn37 are adjacent to Tyr34 and Tyr38, it is possible that their dynamics modulate the formation and migration of the active tyrosyl radicals in DHP-A at pH 7. Another significant difference is that both distal and proximal histidines have a 15-18% smaller S2 value in DHP-B, thus their greater flexibility could account for the higher catalytic activity. The distal histidine grants substrate access to the distal pocket. The greater flexibility of the proximal histidine could also accelerate H2O2 activation at the heme Fe by increased coupling of an amino acid charge relay to stabilize the ferryl Fe(IV) oxidation state in a Poulos-Kraut "push-pull"-type peroxidase mechanism.


Assuntos
Histidina , Poliquetos , Animais , Histidina/química , Isoenzimas/metabolismo , Peróxido de Hidrogênio/metabolismo , Hemoglobinas/química , Peroxidases/química , Peroxidase/química , Poliquetos/química , Poliquetos/metabolismo , Cristalografia por Raios X
2.
J Natl Med Assoc ; 115(6): 566-576, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37903694

RESUMO

PURPOSE: To identify whether there was a disparity in the utilization of immunotherapy in the treatment of black patients with metastatic castration resistant prostate cancer (mCRPC). METHODS: Using the National Cancer Database, we identified patients between 2010- 2015 with likely minimally/asymptomatic mCRPC. We analyzed annual trends for chemotherapy and immunotherapy use and compared utilization by demographic and clinical features. Multivariable analysis was performed to determine predictors of receiving immunotherapy vs chemotherapy. RESULTS: We identified 1301 patients with likely mCRPC. The majority were non Hispanic White (NHW - 63 %) and 23 % were non-Hispanic Black (NHB). Overall, there was increased utilization of immunotherapy in mCRPC from 2010 onwards, with the peak occurring in 2014 (4.6 %). Chemotherapy use increased significantly, peaking in 2014 to 26.1 %. However, the increased utilization of immunotherapy in the mCRPC was mainly seen in White patients: from 50 % to 74.2 % of the cohort. Conversely, there was a decrease in utilization of immunotherapy among Black mCPRC patients: from 50 % to 25.8 %. On multivariable analysis, there was no statistically significant difference between treatment types by race. CONCLUSION: FDA approval of Sipuleucel-T for mCRPC led to increased utilization of immunotherapy shortly thereafter, but this was mainly noted in white patients. Black patients comparatively did not exhibit increased utilization of this novel agent after 2010. Further studies are necessary to help understand barriers to access to new treatment in mCRPC and eliminate the burden of disease in minority populations."


Assuntos
Disparidades em Assistência à Saúde , Neoplasias de Próstata Resistentes à Castração , Humanos , Masculino , População Negra , Imunoterapia , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/patologia , Brancos , Hispânico ou Latino , Disparidades em Assistência à Saúde/etnologia
3.
Clin Chim Acta ; 548: 117517, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37591418

RESUMO

BACKGROUND: A potential contributor to fatigue in kidney transplant recipients (KTR) may be impaired creatine homeostasis. We developed and validated a high-throughput NMR assay allowing for simultaneous measurement of circulating creatine and creatinine, and determined plasma creatine and estimated intramuscular creatine concentrations in KTRs, delineated their determinants and explored their associations with self-reported fatigue. METHODS: An NMR assay was developed and validated for measurement of circulating creatinine and creatine concentrations. Plasma creatine and creatinine concentrations were measured in 618 KTR. Fatigue was assessed using the checklist individual strength. Associations of creatine parameters with fatigue was assessed using linear mixed effect models. RESULTS: The NMR-based assay had good sensitivity, precision and demonstrated linearity across a large range of values. Among KTR, the mean age was 56 ± 13 years, 62% were men and eGFR was 54 ± 18 ml/min/1.73 m2. Plasma creatine concentration was 27 [19-39] µmol/L. Estimated intramuscular creatine concentration was 27 ± 7 mmol/kg. Higher plasma creatine concentration and higher estimated intramuscular creatine concentration were independently associated with a lower total fatigue score and less motivation problems. CONCLUSION: An NMR method for measurement of circulating creatine and creatinine which offers the potential for accurate and efficient quantification was developed. The found associations suggest that improving creatine status may play a beneficial role in mitigating fatigue.


Assuntos
Creatina , Transplante de Rim , Masculino , Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Feminino , Creatinina , Fadiga , Espectroscopia de Ressonância Magnética
4.
Environ Res ; 231(Pt 3): 116094, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37201700

RESUMO

Mesostructured PbO2/TiO2 materials were synthesized to perform electrocatalysis (as electrooxidation, EO) and photoelectrocatalysis for removing diclofenac (DCF), 15 ppm concentration in 0.1 M NaSO4 solutions, at different pH conditions (3.0, 6.0 and 9.0) by applying 30 mA cm-2. Titania nanotubes (TiO2NTs)-based materials were prepared to synthetize with a massive PbO2 deposit on this support to obtain TiO2NTs/PbO2 and a TiO2NTs:PbO2 material consisting in a dispersed PbO2 deposit on TiO2-NTs that allowed the formation of a heterostructured surface of combined composition (TiO2 and PbO2). Organics removal (DCF and byproducts) was monitored through UV-vis spectrophotometry and high-performance liquid chromatography (HPLC) during degradation tests. TiO2NTs/PbO2 electrode was tested in both processes, removing DCF at neutral and alkaline solution conditions in EO while an unimportant photoactivity was registered at this material. Conversely, TiO2NTs:PbO2 was used as electrocatalytic material in EO experiments, achieving more than 50% of DCF removal at pH 6.0 by applying 30 mA cm-2. Also, for first time, the synergic effect was investigated when it was exposed to UV irradiation in photoelectrocatalytic experiments, enhancing its efficacy (⁓more than 20%) to remove DCF from a solution with 15 ppm over performance removals achieved (56%) when EO was applied under similar conditions. Chemical Oxygen Demand (COD) analyses showed that significantly higher DCF degradation is reached under photoelectrocatalysis, since COD values decrease a 76% against a 42% decrease achieved with electrocatalysis. Scavenging experiments showed a significant participation on the pharmaceutical oxidation process through the generation of photoholes (h+), hydroxyl radicals and sulfate-based oxidants.


Assuntos
Nanotubos , Poluentes Químicos da Água , Água , Diclofenaco , Chumbo , Óxidos/química , Titânio/química , Oxirredução , Nanotubos/química , Poluentes Químicos da Água/análise
5.
Sci Rep ; 13(1): 4799, 2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-36959323

RESUMO

Thermal neutron detection is a key subject for nuclear physics research and also in a wide variety of applications from homeland security to nuclear medicine. In this work, it is proposed a novel flexible and conformable composite thermal neutron scintillator based on a fully enriched Lithium Tetraborate preparation ([Formula: see text]Li[Formula: see text]B[Formula: see text]O[Formula: see text]) combined with a phosphorescent inorganic scintillator powder (ZnS:Ag), and is then distributed into a polydimethylsiloxane matrix. The proposed scintillator shows a good neutron detection efficiency (max. [Formula: see text] 57% with respect to the commercial EJ-420), an average light output of [Formula: see text] 9000 ph/neutron-capture, a remarkable insensitivity to [Formula: see text]-rays (Gamma Rejection Ratio <10[Formula: see text]), and an extraordinary flexibility, so as to reach extremely small curvature radii, down to 1.5 mm, with no signs of cracking or tearing. Its characteristics make it suitable to be employed in scenarios where non-standard geometries are needed, for example, to optimize the detector performance and/or maximize the detection efficiency. Finally, the response of a hybrid detector made of a plastic scintillator, wrapped with the proposed scintillator, coupled to a silicon photomultiplier array is described, and the excellent discrimination between [Formula: see text]-rays, fast and thermal neutrons resulting from data processing is demonstrated.

6.
Materials (Basel) ; 17(1)2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38203988

RESUMO

Advanced oxidation processes stand as green alternatives for the decontamination of waste waters. Photocatalysis is an advanced oxidation process in which a semiconductor material absorbs photon energy and triggers redox reactions capable of degrading organic pollutants. Titanium dioxide (TiO2, titania) represents one of the most popular choices of photocatalytic materials, however the UV-activation of its anatase phase and its high charge recombination rate decrease its photocatalytic activity and weaken its potential. Graphene oxide is a 2D carbon nanomaterial consisting of exfoliated sheets of hexagonally arranged carbons decorated with oxygen- and hydrogen- functional groups. Composite nanomaterials consisting of titania nanoparticles and graphene oxide have proven to enhance the photocatalytic activity of pure TiO2. In this review, we present a thorough literature review of ternary nanocomposites based on synthesized or commercial titania nanoparticles and GO (or reduced GO) particularly used for the photodegradation of dyes. GO/TiO2 has been enriched primarily with metals, semiconductors and magnetic nanomaterials, proving a superior dye degradation performance and reusability compared to bare TiO2. Ongoing challenges and perspectives are outlined.

7.
Cureus ; 14(2): e22502, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35371808

RESUMO

Introduction Although women remain vastly underrepresented in urology, the proportion of female urology residents and practicing urologists has steadily increased over the last four decades. However, it remains critical to evaluate the representation of females in the pipeline when examining trainees and practicing urologists. As it pertains to leadership positions, the gender distribution among the board of directors (BOD) and committee chairs in the American Urological Association (AUA) subspecialties has not been studied to date. Therefore, we plan to analyze the proportion of females among the BOD and committee chairs in different subspecialty societies recognized by the AUA over time. Methods We conducted a cross-sectional observational study, quantitatively comparing the composition of gender in BOD and Committee Chair members belonging to different AUA-recognized subspecialty societies from 2014 to 2020. The websites for each subspecialty society were searched and contacted. Results We evaluated BODs from 10 AUA subspecialty societies and committee chair members from 6 AUA subspecialty societies. From 2014 to 2020, the total proportion of female BOD amongst all AUA sub-specialty societies did not change significantly, with a small increase from 10.6% (n = 29) to 13.5% (n = 36). However, female representation among committee chair members significantly increased from 9.8% (n = 20) to 19.2% (n = 44; p = 0.006), along with the total number of women in urology, from 897 (8.9%) to 1,375 (10.3%). Increases in female representation were seen in the Society for the Study of Male Reproduction (SSMR) from 0% to 9% and in the Indian American Urological Association (IAUA) from 4% to 13%. Of note, there were no elected female board members in the Society of Urologic Oncology (SUO) or the Urologic Society for Transplantation and Renal Surgery (USTRS) from 2014 to 2020. Conclusion Females remain a minority in leadership positions at AUA sub-specialty societies despite increased female representation in recent years. Future efforts should promote the advancement of women to positions of leadership to reflect the changing landscape of the urology workforce and surgical specialties.

8.
Parasit Vectors ; 15(1): 57, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35177110

RESUMO

BACKGROUND: Emerging and re-emerging vector-borne diseases (VBDs) pose a recurring threat to tropical countries, mainly due to the abundance and distribution of the Aedes aegypti mosquito, which is a vector of the Zika, dengue, chikungunya, and yellow fever arboviruses. METHODS: Female 3-5 day-old Ae. aegypti were distributed into two experimental groups: group I-survey of cultivable bacteria; sucrose group: fed only on sucrose, i.e., non-blood-fed (UF); blood-fed group: (i) fed with non-infected blood (BF); (ii) fed with blood infected with the Zika virus (BZIKV); (iii) pretreated with penicillin/streptomycin (pen/strep), and fed with non-infected blood (TBF); (iv) pretreated with pen/strep and fed blood infected with ZIKV, i.e., gravid with developed ovaries, (TGZIKV); group II-experimental co-infections: bacteria genera isolated from the group fed on sucrose, i.e., non-blood-fed (UF). RESULTS: Using the cultivable method and the same mosquito colony and ZIKV strain described by in a previous work, our results reveled 11 isolates (Acinetobacter, Aeromonas, Cedecea, Cellulosimicrobium, Elizabethkingia, Enterobacter, Lysinibacillus, Pantoea, Pseudomonas, Serratia, and Staphylococcus). Enterobacter was present in all evaluated groups (i.e., UF, BF, BZIKV, TBF, and TGZIKV), whereas Elizabethkingia was present in the UF, BZIKV, and TBF groups. Pseudomonas was present in the BZIKV and TBF groups, whereas Staphylococcus was present in the TBF and TGZIKV groups. The only genera of bacteria that were found to be present in only one group were Aeromonas, Lysinibacillus, and Serratia (UF); Cedacea, Pantoea and Acinetobacter (BF); and Cellulosimicrobium (BZIKV). The mosquitoes co-infected with ZIKV plus the isolates group fed on sucrose (UF) showed interference in the outcome of infection. CONCLUSIONS: We demonstrate that the distinct feeding aspects assessed herein influence the composition of bacterial diversity. In the co-infection, among ZIKV, Ae. aegypti and the bacterial isolates, the ZIKV/Lysinibacillus-Ae. aegypti had the lowest number of viral copies in the head-SG, which means that it negatively affects vector competence. However, when the saliva was analyzed after forced feeding, no virus was detected in the mosquito groups ZIKV/Lysinibacillus-Lu. longipalpis and Ae. aegypti; the combination of ZIKV/Serratia may interfere in salivation. This indicates that the combinations do not produce viable viruses and may have great potential as a method of biological control.


Assuntos
Aedes , Microbiota , Infecção por Zika virus , Zika virus , Animais , Feminino , Mosquitos Vetores
9.
Cureus ; 14(12): e32699, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36686106

RESUMO

Introduction Many men receiving temporary androgen deprivation therapy (ADT) for localized prostate cancer fail to achieve baseline testosterone levels after cessation. Testosterone recovery in men with localized prostate cancer receiving temporary ADT was assessed. Methods A global federated health research network (TriNetX) was used to identify men diagnosed with prostate cancer undergoing temporary ADT. Two cohorts were identified: men receiving luteinizing hormone-releasing hormone (LHRH) antagonists or LHRH agonists, and men receiving combined ADT (LHRH agonist and antiandrogens). Further stratification was based on a treatment duration of six months (short-term) or 18 months (long-term) to compare testosterone (T) recovery profiles five years after ADT cessation. Results A total of 28,583 men received LHRH agonist or antagonist therapy alone, and 20,188 men received combination ADT. A total of 46.7% of men who received short-term LHRH agonists or antagonists and 40.6% of men who received short-term combined ADT, recovered to mean baseline T levels at five years. Only men who received short-term LHRH agonists/antagonists recovered to eugonadal levels at the five-year follow-up. Around 50% of men who received long-term LHRH agonist/antagonist therapy and 10.7% of men who received combined ADT, recovered to mean baseline T levels at five years. However, neither group recovered to eugonadal T levels. Conclusions At the five-year follow-up after ADT cessation, most patients failed to recover to their mean baseline and eugonadal T levels. Given that testosterone deficiency is associated with metabolically adverse changes in body composition, increased insulin resistance, impaired bone health, and hypogonadal symptoms, serum T levels must be closely monitored in men receiving ADT following treatment cessation.

11.
Molecules ; 26(24)2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34946522

RESUMO

As surface-enhanced Raman spectroscopy (SERS) continues developing to be a powerful analytical tool for several probes, four important aspects to make it more accessible have to be addressed: low-cost, reproducibility, high sensibility, and recyclability. Titanium dioxide nanotubes (TiO2 NTs) prepared by anodization have attracted interest in this field because they can be used as safe solid supports to deposit metal nanoparticles to build SERS substrate nanoplatforms that meet these four desired aspects. TiO2 NTs can be easily prepared and, by varying different synthesis parameters, their dimensions and specific features of their morphology can be tuned allowing them to support metal nanoparticles of different sizes that can achieve a regular dispersion on their surface promoting high enhancement factors (EF) and reproducibility. Besides, the TiO2 photocatalytic properties enable the substrate's self-cleaning property for recyclability. In this review, we discuss the different methodological strategies that have been tested to achieve a high performance of the SERS substrates based on TiO2 NTs as solid support for the three main noble metal nanoparticles mainly studied for this purpose: Ag, Au, and Pt.

12.
Water Environ Res ; 93(12): 3037-3048, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34676632

RESUMO

Contaminant substances consist of chemical elements that present the potential to adversely impact the ecology of the environment, thus representing a threat to local fauna and flora. In this context, heavy metals are critical agents that, depending on the nature and level, are potentially toxic to living organisms. In order to evaluate the bioaccumulation of heavy metals in the Santos estuary and to determine the potential influence of salinity gradient on the heavy metal bioconcentration, the present study measured the concentrations of As, Cd, Pb, Cu, Cr, Fe, Ni, and Zn in two bivalve species (Crassostrea rhizophorae and Perna Perna) sampled at different sites of Santos Bay, in the southeastern region of Brazil. Throughout the study, the "sentinel species" used were effective in bioaccumulating contaminants. In oysters, based on the Brazilian legislation, critical limits were exceeded for As, Zn, Cu, and Cr. In the case of mussels, on the other hand, only for As, Zn, and Cr, the critical limits were overcome. In the present study, obtained data suggested salinity as a determinant parameter in As incorporation processes of bivalve mollusks. PRACTITIONER POINTS: The present study presents important results for the development of environmental management policies in estuarine environments. The present study points out differences between different organisms as biomonitors, providing subsidies for the decision of an effective biomonitoring program. The present study discusses values of contaminants as a danger to public health in Santos Bay, which can be extrapolated to other similar environments around the world.


Assuntos
Bivalves , Metais Pesados , Poluentes Químicos da Água , Animais , Baías , Brasil , Monitoramento Ambiental , Metais Pesados/análise , Poluentes Químicos da Água/análise
13.
RSC Adv ; 11(12): 6509-6516, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-35423200

RESUMO

Graphene oxide (GO) has lately become an interesting biomaterial due to its stunning properties and versatility, its claimed antimicrobial activity holds promise for potential health applications. Nonetheless, multiple reports investigating GO antibacterial activity lack rigor and uniformity on several aspects which are crucial when evaluating this effect. In this work, we highlight and address these parameters: morphology of the materials, exposure time, exposure methodology and concentration. We investigate the effect of GO and GO-based metallic composites observing these parameters on two pathogenic bacteria. Our nanomaterials have been characterized by means of SEM, EDX, DLS, FTIR and Raman spectroscopies. Escherichia coli and Salmonella Typhimurium suspended in saline solutions (no growth medium) have been exposed to GO (lateral size = 100 nm), silver nanoparticles, ceria nanoparticles, GO/silver and GO/ceria aqueous solutions for 0, 5, 15, 30, 60 and 90 minutes, before plating. Our experiments indicate that no prior exposure of the materials to bacteria (0 min) results in poor inactivation rates independently of concentration, while increasing times of interaction enhance inactivation. Moreover, our experiments show concentration-dependent results showing higher activity for concentrations of 100 µg mL-1; and prove that 30 minutes of exposure are sufficient to deploy the antimicrobial effects of these materials. GO possesses the lowest inactivation rate, and the presence of silver and ceria nanoparticles in the GO surface boosts its antimicrobial effect. Thus, the enhancement of the antibacterial activity of graphene oxide relies on 30 minutes of interaction in water, concentration of 100 µg mL-1, and its decoration by silver/ceria nanoparticles.

14.
Nanotechnology ; 32(8): 085602, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33166942

RESUMO

Functionalized carbon nanospheres have been synthesized in situ via a facile chemical vapor deposition strategy, fabricated by the pyrolysis of toluene/ethanol mixtures at different percentages (0, 1, 2, 3, 4, and 5 wt% of ethanol). The as-grown nanospheres have been characterized using transmission electron microscopy, scanning electron microscopy, Raman and Fourier transform infrared spectroscopy, x-ray diffraction, nitrogen adsorption, zeta potential measurements and x-ray photoelectron spectroscopy. Results indicate that the incorporation of ethanol in the precursor solution reflected in the presence of oxygen and hydrogen functional groups, the highest functionalized nanospheres without compromising the morphology of the sample were yielded at 3 wt% concentration. These in situ added functional groups rendered the carbon nanostructures enhancedly dispersible and stable in water, avoiding post-synthesis and harsh chemicals processing; envisaging thus applications of the nanospheres in the biomedical field where hydrophilicity of the nanomaterials is mandatory.

15.
J Dent Educ ; 81(1): 44-53, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28049677

RESUMO

In 2006, the Scholars Program in Dental Leadership (SPDL) was created at the University of Michigan School of Dentistry with the aim of preparing dental students to take on leadership roles in their profession and communities. The aims of this quantitative study were to investigate how SPDL alumni and current participants evaluated this program; to assess whether SPDL alumni evaluated their leadership-related educational experiences, leadership perceptions, and attitudes towards leadership activities in dentistry more positively than did non-SPDL dental students and general dentists; and to explore if leadership-related educational/clinical experiences were correlated with these constructs. Participants were 218 of 431 dental students across all four years (response rate 51%), 32 of whom were participants in the SPDL; 32 of 53 SPDL alumni (response rate 60%); and 595 of 3,000 general dentists invited to participate (response rate 20%). Both current and past SPDL participants evaluated the program on average positively (3.75 and 3.92, respectively, on a five-point scale). Non-SPDL students and alumni evaluated leadership-related educational experiences more positively than did the dentists (3.65/3.61 vs. 2.49; p<0.001). Their evaluations of different indicators of dental leadership differed as well. Students and alumni evaluated being recognized (4.40/4.60 vs. 4.20; p<0.001), making a contribution to the community (4.04/4.40 vs. 3.81; p<0.001), and views on practice efficiency (4.61/4.53 vs. 4.36; p<0.001) more positively than did the general dentists. The SPDL alumni had more positive evaluations of organized dentistry (4.17 vs. 3.77/3.71; p=0.045) and academia (3.97 vs. 3.48/3.45; p=0.01) than did the students and general dentists. Educational/clinical experiences were positively correlated with most leadership-related constructs. These results showed that the SPDL positively affected alumni perceptions of leadership indicators and attitudes.


Assuntos
Odontólogos , Educação em Odontologia , Liderança , Estudantes de Odontologia , Adulto , Idoso , Atitude Frente a Saúde , Odontólogos/psicologia , Educação em Odontologia/organização & administração , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Programas e Projetos de Saúde , Estudantes de Odontologia/psicologia , Adulto Jovem
16.
J Appl Biomater Funct Mater ; 14(4): e423-e430, 2016 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-27647388

RESUMO

BACKGROUND: Driven by the potential biological applications of graphene, many groups have studied the response of cells exposed to graphene oxide (GO). In particular, investigations of bacteria indicate that there are 2 crucial parameters, which so far have only been investigated separately: GO size and exposure methodology. Our study took into account both parameters. We carefully characterized the samples to catalog sizes and structural properties, and tested different exposure methodologies: exposure in saline solution and in the presence of growth media. Furthermore, we performed experiments with peripheral blood mononuclear cells exposed to our GO materials. METHODS: Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the morphology and composition of different samples of GO: GO-H2O, GO-PBS and GO-MG. Our samples had 2D sizes of ~100 nm (GO-H2O and GO-PBS) and >2 µm (GO-MG). We tested antibacterial activity and cytotoxicity toward peripheral blood mononuclear cells of 3 different GO samples. RESULTS: A size-dependent growth inhibition of Escherichia coli (DH5 α) in suspension was found, which proved that this effect depends strongly on the protocol followed for exposure. Hemocompatibility was confirmed by exposing peripheral blood mononuclear cells to materials for 24 hours; viability and apoptosis tests were also carried out. CONCLUSIONS: Our experiments provide vital information for future applications of GO in suspension. If its antibacterial properties are to be potentiated, care should be taken to select 2D sizes in the micrometer range, and exposure should not be carried out in the presence of grow media.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Escherichia coli/ultraestrutura , Grafite/farmacologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/ultraestrutura , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Viabilidade Microbiana/efeitos dos fármacos
17.
Sci Rep ; 6: 24301, 2016 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-27102827

RESUMO

Graphene has emerged as a promising material for infrared (IR) photodetectors and plasmonics. In this context, wafer scale epitaxial graphene on SiC is of great interest in a variety of applications in optics and nanoelectronics. Here we present IR reflectance spectroscopy of graphene grown epitaxially on the C-face of 6H-SiC over a broad optical range, from terahertz (THz) to mid-infrared (MIR). Contrary to the transmittance, reflectance measurements are not hampered by the transmission window of the substrate, and in particular by the SiC Reststrahlen band in the MIR. This allows us to present IR reflectance data exhibiting a continuous evolution from the regime of intraband to interband charge carrier transitions. A consistent and simultaneous analysis of the contributions from both transitions to the optical response yields precise information on the carrier dynamics and the number of layers. The properties of the graphene layers derived from IR reflection spectroscopy are corroborated by other techniques (micro-Raman and X-ray photoelectron spectroscopies, transport measurements). Moreover, we also present MIR microscopy mapping, showing that spatially-resolved information can be gathered, giving indications on the sample homogeneity. Our work paves the way for a still scarcely explored field of epitaxial graphene-based THz and MIR optical devices.

18.
Oral Maxillofac Surg ; 20(2): 123-33, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26572899

RESUMO

This double-blind, split-mouth, and randomized study was aimed to compare the efficacy of dexamethasone and ketorolac tromethamine, through the evaluation of pain, edema, and limitation of mouth opening. Thirty-four individuals aged 18-26 years, having bilateral mandibular third molars, in a similar position, were selected. Two different surgical procedures were performed on the same individual by the single surgeon. For an extraction, the individual received 1 capsule of 10 mg ketorolac tromethamine 1 h before surgery and every 8 h for 2 days. For the extraction of the contralateral side, the individual received 1 capsule of 8 mg dexamethasone 1 h before surgery and 1 placebo capsule every 8 h for 2 days. Sodium metamizol, 500 mg, was given as rescue medication in postoperative. Pain was assessed by the Visual Box Scale-11 points (BS-11) at 24 h postoperative. Edema (metric measurement) and the maximum mouth opening (interincisal) were recorded in the pre-operative, 24 h, 48 h, 72 h and 7 days postoperatively. The results showed that both therapeutic treatments used were effective in the postoperative, and there were no statistically significant differences between the groups for the pain and edema variables. However, for the limitation of mouth opening, 24 h and 7 days postoperatively, the dexamethasone group had a lower limitation of mouth opening, behaving better than the ketorolac for this variable in these periods. Due also to the higher margin of safety, the use of dexamethasone as a single dose becomes a more suitable alternative for use in routine surgical extractions of third molars.


Assuntos
Anti-Inflamatórios/uso terapêutico , Dexametasona/uso terapêutico , Cetorolaco de Trometamina/uso terapêutico , Dente Serotino/cirurgia , Extração Dentária , Adolescente , Adulto , Dipirona/uso terapêutico , Método Duplo-Cego , Esquema de Medicação , Edema/etiologia , Feminino , Humanos , Masculino , Pré-Medicação , Resultado do Tratamento , Trismo/etiologia , Escala Visual Analógica , Adulto Jovem
19.
J Phys Chem A ; 118(42): 9901-13, 2014 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-25237715

RESUMO

Pigment-based molecular arrays, especially those based on porphyrins, have been extensively studied as viable components of artificial light harvesting devices. Unlike porphyrins, bacteriochlorins absorb strongly in the NIR, yet little is known of the applicability of covalently linked bacteriochlorin-based arrays in this arena. To lay the foundation for future studies of excited state properties of such arrays, we present a systematic study of the ground state electronic structure of zinc bacteriochlorin (ZnBC) molecular arrays with various linkers and linker attachment sites (meso vs ß) employing density functional theory in combination with the energy-based fragmentation (EBF) method, and the EBF with molecular orbitals (EBF-MO) method. We find that the level of steric hindrance between the ZnBC and the linker is directly correlated with the amount of ground sate electronic interactions between the ZnBCs. Low steric hindrance between the ZnBC and the linker found in alkyne-linked arrays results in strongly interacting arrays that are characterized by a decrease in the HOMO-LUMO energy gaps, large orbital energy dispersion in the frontier region, and low ZnBC-linker rotational barriers. In contrast, sterically hindered linkers, such as aryl-based linkers, result in weakly interacting arrays characterized by increased orbital energy degeneracy in the frontier region and high ZnBC-linker rotational barriers. For all linkers studied, the level of steric hindrance decreases when the ZnBCs are linked at the ß position. Hence, ZnBC arrays that exhibit strong, weak, or intermediate ground-state electronic interactions can be realized by adjusting the level of steric hindrance with a judicious choice of the linker type and linker attachment site. Such tuning may be essential for design of light harvesting arrays with desired spectral properties.


Assuntos
Compostos Organometálicos/química , Porfirinas/química , Zinco/química , Simulação de Dinâmica Molecular , Teoria Quântica , Espectroscopia de Luz Próxima ao Infravermelho
20.
Rev. estomat. salud ; 22(1): 9-14, 20140000.
Artigo em Espanhol | LILACS, COLNAL | ID: biblio-877879

RESUMO

Introducción: La contaminación del cepi - llo dental es importante para la salud oral y general, puesto que facilita la higiene oral. Como se contamina después del uso, pue- de ser fuente de infecciones. Los cepillos antibacteriales controlan la contaminación. Obtetivo: Se determinó la efectividad de los cepillos dentales antibacteriales en la inhibición del crecimiento de microorga- nismos patogénicos como A. actinomyce - temcomitans y E. cloacae . En este estudio se incluyeron, tres marcas de cepillos dentales que fueron Oral-B® antibacterial y Colgate® antibacterial incluido un cepillo convencional no antibacterial de la marca Colgate. Materiales y métodos: Un total de 48 cepillos fueron inoculados, 24 con A. ac- tinomycetemcomitans y 24 con E.cloacae y la viabilidad microbiana fue establecida después de diversos tiempos así: 24 horas, 4 días, 12 días y 24 días, en un experimento por duplicado al evaluar el crecimiento bacteriano. Resultados: A las 24 horas los cepillos cumplen con su poder antibacterial incluido el cepillo convencional, el cepillo Oral-B® antibacterial y el Colgate®antibacterial inhibieron completamente el crecimiento de las colonias de el A. actinomycete - mcomitans , mientras que el cepillo Oral B antibacterial permitió el crecimiento de E. cloacae . Finalmente se encontró que con el paso de tiempo 24 días, los cepillos dentales perdieron el efecto antibacterial contra ambos organismos. Conclusión: Los cepillos antibacteriales logran inhibir el crecimiento de A. acti - nomycetemcomitans entre las 24 horas y los 4 días, pero su efecto antibacterial se pierde con el tiempo. Un microorganismo súper-infectante como el E. cloacae es más resistente contra antibacteriales presentes en los cepillos dentales...(Au)


Objective: Toothbrush contamination is important to the oral health and the general health. Toothbrush is recommended to the regular elimination of the bacterial plaque; however it is also a potential source infec - tion since it gets contaminated. Antibacte - rial toothbrushes were introduced to control the microbial contamination. Materials and methods: The effectiveness of antibacterial toothbrushes on the growth inhibition of A. actinomycetemcomitans , and E. cloacae were determined. This study included, three brands of dental brushes which were Oral-B® antibacterial Colgate® antibacterial I and as control one conventional dental brush non-antibacterial of Colgate. Materials and methods: A total of 48 dental brushes were inoculated, 24 with A. actinomycetemcomitans and 24 with E. cloacae and the microbial viability was established after diverse times as follows: 24 hours, 4 days, 12 days and 24 days, in an experiment for duplicate, evaluating the bacterial growth. Results: At 24 hours the dental brushes fulfill their antibacterial efficacy including the conventional dental brush, The Oral-B® antibacterial toothbrush and the Colgate® antibacterial controlled completely the growth of the colonies of the A. actinomy- cetemcomitans , while the Oral-B anti - bacterial toothbrush allowed E. cloacae's growth. Finally after 24 days it was found that the inoculation the dental brushes does not inhibited either the A. actinomycete - mcomitans or neither the E. cloacae . Conclusions: The antibacterial brushes are able to inhibit the growth of A. actinomyce - temcomitans between 24 hours to 4 days, but this antibacterial effect is lost over the time. A super-infectious microorganism such as E. cloacae is more resistant to antibacterials present on dental brushes...(Au)


Assuntos
Humanos , Aggregatibacter actinomycetemcomitans , Poluição Ambiental , Odontologia , Diagnóstico Bucal , Enterobacteriaceae , Microbiologia , Medicina Bucal , Enterobacter cloacae , Higiene Bucal
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