RESUMO
The rapid development of drug-resistant characteristics in pathogenic viral, bacterial, and fungal species and the consequent spread of infectious diseases are currently receiving serious attention. Indeed, there is a pressing demand to explore novel materials and develop new strategies that can address these issues of serious concern. Nanomaterials are currently proving to be the most capable therapeutic agents to cope with such hazards. The exceptional physiochemical properties and impressive antimicrobial capabilities of nanoparticles have provoked their utilization in biomedical fields. Nanomaterials of both organic and inorganic nature have shown the capabilities of disrupting microbial cells through different mechanisms. Along with the direct influence on the microbial cell membrane, DNA and proteins, these nanomaterials produce reactive oxygen species (ROS) that damage cell components and viruses. Currently, a serious hazard associated with these antimicrobial nanomaterials is their toxicity to human and animal cells. Extensive studies have reported the dose, time, and cell-dependent toxicology of various nanomaterials, and some have shown excellent biocompatible properties. Nevertheless, there is still debate regarding the use of nanomaterials for medical applications. Therefore, in this review, the antimicrobial activities of various nanomaterials with details of their acting mechanisms were compiled. The relative toxic and biocompatible behavior of nanomaterials emphasized in this study provides information pertaining to their practical applicability in medical fields.
Assuntos
Anti-Infecciosos/administração & dosagem , Anti-Infecciosos/efeitos adversos , Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Fungos/efeitos dos fármacos , Nanoestruturas/administração & dosagem , Nanoestruturas/efeitos adversos , Animais , Anti-Infecciosos/química , Materiais Biocompatíveis/administração & dosagem , Materiais Biocompatíveis/efeitos adversos , Materiais Biocompatíveis/química , Humanos , Nanoestruturas/químicaRESUMO
OBJECTIVE: To develop a dental hygiene care programme based on the specific needs of patients with mental disorders and to suggest practical guidelines to improve the oral health care of these patients. METHODS: A total of 73 patients with mental illness participated in the study. The patients were randomly classified into three groups and followed over 12 weeks at 4-week intervals. A newly designed dental hygiene care programme using flash-based video, brochures and a toothpick method was implemented by five dental hygienists. Plaque index, stimulated saliva, subjective oral dryness and dental caries activity were analysed as outcome variables. RESULTS: Results showed that the dental plaque index significantly decreased after each session (P < 0.0001) in all three groups, and significant differences were found between groups (P = 0.036). Patients' oral dryness decreased significantly, but stimulated saliva and dental caries activity did not improve. CONCLUSION: The results of this study suggest that the dental hygiene care programme, which made use of a short, 10-min flash-based video and brochures every 4 weeks, was effective in reducing the dental plaque index of patients with mental disorders.
Assuntos
Placa Dentária/prevenção & controle , Profilaxia Dentária/métodos , Transtornos Mentais , Adulto , Idoso , Recursos Audiovisuais , Assistência Odontológica para a Pessoa com Deficiência , Testes de Atividade de Cárie Dentária , Dispositivos para o Cuidado Bucal Domiciliar , Índice de Placa Dentária , Feminino , Seguimentos , Humanos , Masculino , Transtornos Mentais/tratamento farmacológico , Pessoa de Meia-Idade , Avaliação das Necessidades , Higiene Bucal/educação , Folhetos , Educação de Pacientes como Assunto/métodos , Saliva/metabolismo , Escovação Dentária/instrumentação , Escovação Dentária/métodos , Resultado do Tratamento , Gravação em Vídeo , Xerostomia/classificação , Adulto JovemRESUMO
AIM: To investigate the effect of nonthermal atmospheric pressure plasma on intracoronal tooth bleaching in blood stained human teeth. METHODOLOGY: Forty extracted single-root and blood stained human teeth were used. The teeth were randomly divided into two groups (n=20): group 1 received 30% HP activated by nonthermal atmospheric pressure plasma in the pulp chamber for 30 min, whilst group 2 received 30% HP alone in the pulp chamber for 30 min. The overall colour changes (ΔE) were assessed using the Commission Internationale de L'Eclairage (CIE) Lab Colour System. The data were analysed using Student's t-test to determine the significant differences. RESULTS: The temperature of all teeth was maintained at approximately 37 °C during plasma bleaching. The plasma treatment with 30% HP resulted in significantly higher bleaching efficacy compared to 30% HP alone in discoloured teeth (P<0.05). The average ΔE values of group 1 and group 2 were 9.24 (0.37) and 4.47 (1.62), respectively, at 30 min. CONCLUSIONS: The application of nonthermal atmospheric pressure plasma to intracoronal bleaching could be a novel and efficient therapy in the bleaching of haemorrhagically stained teeth.
Assuntos
Cavidade Pulpar/efeitos dos fármacos , Terapia por Estimulação Elétrica/métodos , Peróxido de Hidrogênio/administração & dosagem , Clareadores Dentários/administração & dosagem , Clareamento Dental/métodos , Descoloração de Dente/terapia , Pressão Atmosférica , Manchas de Sangue , Temperatura Corporal , Humanos , Descoloração de Dente/etiologiaRESUMO
The aetiology of non-carious cervical lesions (NCCLs) is not well understood and still controversial. The aim of this ex-vivo study was to examine the morphological characteristics of NCCLs for clinical evidence of enamel loss above the cemento-enamel junction (CEJ) as suggested by the abfraction theory. Fifty extracted human teeth with various types of NCCLs were collected and scanned by micro computed tomography. The reconstructed three-dimensional models were evaluated from multiple aspects, including longitudinal cross-section series. The location of internal line angle and proximal exits of the lesions were evaluated in relation to the level of CEJ. The coronal margins of the lesions were inspected for evidence of enamel loss above the CEJ using the bucco-lingual longitudinal sectional images. Coronal margins of the lesions were located along and/or under the CEJ for all of the 50 samples. In most of the lesions, regardless of lesion type, the proximal exits and internal line angles were located below the CEJ. This study did not detect clinical evidence of enamel loss above the occlusal margin of NCCLs as would have been expected according to the general abfraction mechanism.
Assuntos
Esmalte Dentário/patologia , Colo do Dente/patologia , Desgaste dos Dentes/patologia , Humanos , Colo do Dente/diagnóstico por imagem , Desgaste dos Dentes/diagnóstico por imagem , Microtomografia por Raio-XRESUMO
BACKGROUND: Recent studies in mice experimental models with acute ischaemic injury revealed that erythropoietin (EPO) has numerous tissue-protective effects in the heart, brain and kidneys. We therefore explored the tissue-protective properties of chronic EPO treatment in an experimental model of the db/db mouse with diabetic heart injury. MATERIAL AND METHODS: We randomly treated 11 db/db mice with placebo (saline), 0.4 microg of the continuous erythropoietin receptor activator (CERA) per week (n = 11) or 1.2 microg CERA per week (n = 11) for 14 weeks, and analysed cardiac tissue. The lower CERA dose was a non-haematologically effective dose, whereas the second increased the haematocrit. RESULTS: Compared with mice in the placebo group, CERA-treated mice had a reduction in TGF-beta(1) and collagen I expression in cardiac tissue (P < 0.01 vs. higher dose CERA). In addition, an increased expression of the pro-survival intracellular pathway p-AKT was observed (P < 0.05 vs. higher dose CERA). The values for the lower C.E.R.A had an intermediate nonsignificant effect. Furthermore, we were able to show that atrial natriuretic peptide (ANP) expression was increased in both CERA groups. CONCLUSIONS: Chronic treatment with CERA protects cardiac tissue in diabetic animals, i.e. it inhibits molecular pathways of cardiac fibrosis, and the effects are dose-dependent.
Assuntos
Angiopatias Diabéticas/metabolismo , Eritropoetina/administração & dosagem , Miocárdio/metabolismo , Polietilenoglicóis/administração & dosagem , Animais , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Angiopatias Diabéticas/tratamento farmacológico , Angiopatias Diabéticas/genética , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Imuno-Histoquímica , Masculino , Camundongos , Proteínas RecombinantesRESUMO
The aim of this study was to compare the cell compatibility of silk and polyglycolic acid (PGA) scaffolds cultured in vitro with mesenchymal stem cells (MSCs) and peripheral blood mononuclear cells (PBMCs) to their biocompatibility in vivo following implantation. Scaffolds were knitted with silk or PGA thread and the average efficiency of cell attachment was 35 +/- 4% and 17 +/- 2% in the PGA and silk scaffold groups. Thus, the initial attachment of the MSC cells to the PGA scaffold was superior to the initial attachment of the cells on the silk scaffold. After 21 days in culture, the average cell density on the silk scaffold was 5.8 +/- 0.5 x 10(5) cells, and the average cell density of the PGA scaffolds was 6.34 +/- 0.5 x 10(5) cells. In addition, there was no cell cytoxicity observed with either scaffold. However, the immune response of in vitro cultured PBMCs was significantly higher with the PGA scaffold than with the silk scaffold. The proliferation of the PBMCs cultured on the PGA scaffold was two times greater than that of those cultured on the silk scaffold after 3 days of culture. In addition, the secretion of IL-1 by the PBMCs cultured on the PGA scaffold was superior to that of the PBMCs cultured on the silk scaffold. The secretion of IL-1beta and IFN-gamma was increased by about 50% when the PBMCs were cultured with the PGA scaffold. Silk and PGA scaffolds were also implanted subcutaneous in rats. Histological evaluation of the scaffold explants revealed the presence of monocytes and macrophages in PGA scaffold. The inflammatory tissue reaction was more conspicuous on the PGA scaffold than on the silk scaffold. These results suggest that the results of in vitro PBMC cultures were more closely related to the in vivo results of implantation than the results of in vitro MSC cultures.
Assuntos
Materiais Biocompatíveis , Mesoderma/citologia , Monócitos/citologia , Animais , Células Cultivadas , Microscopia Eletrônica de Varredura , Ratos , Ratos Sprague-DawleyRESUMO
AIM: To evaluate how different cross-sectional designs affect stress distribution in nickel-titanium (NiTi) instruments during bending, torsion and simulated shaping of a curved canal. METHODOLOGY: Four NiTi rotary instruments with different cross-sectional geometries were selected: ProFile and HeroShaper systems with a common triangle-based cross section, Mtwo with an S-shaped rectangle-based design and NRT with a modified rectangle-based design. The geometries of the selected files were scanned in a micro-CT and three-dimensional finite-element models were created for each system. Stiffness characteristics for each file system were determined in a series of bending and torsional conditions. Canal shaping was simulated by inserting models of the rotating file into a 45 degrees curved canal model. Stress distribution in the instruments was recorded during simulated shaping. After the instruments were retracted from the canal, residual stresses and permanent bending of their tips due to plastic deformation were determined. RESULTS: The greatest bending and torsional stiffness occurred in the NRT file. During simulated shaping, the instruments with triangle-based cross-sectional geometry had more even stress distributions along their length and had lower stress concentrations than the instruments with rectangle-based cross sections. Higher residual stresses and plastic deformations were found in the Mtwo and NRT with rectangle-based cross-sectional geometries. CONCLUSIONS: Nickel-titanium instruments with rectangle-based cross-sectional designs created higher stress differentials during simulated canal shaping and may encounter higher residual stress and plastic deformation than instruments with triangle-based cross sections.
Assuntos
Ligas Dentárias/química , Níquel/química , Preparo de Canal Radicular/instrumentação , Titânio/química , Cavidade Pulpar/anatomia & histologia , Módulo de Elasticidade , Desenho de Equipamento , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional , Teste de Materiais , Maleabilidade , Estresse Mecânico , Propriedades de Superfície , Torção Mecânica , Microtomografia por Raio-XRESUMO
The aqueous fraction of Triton X-100-soluble proteins (TSP-Aq) of Mycobacterium tuberculosis cell wall was reported to stimulate T-cell responses in peripheral blood monocytes from tuberculosis (TB) patients and to induce Th1 cytokines, suggesting presence of protective antigens. In this study, therefore, we examined the protective efficacy of TSP-Aq against M. tuberculosis infection in a mouse model. C57BL/6 mice were immunized with TSP-Aq or culture filtrate proteins (CFP) mixed with incomplete Freund's adjuvant or with BCG followed by i.v. challenge with M. tuberculosis H37Rv. TSP-Aq induced strong interferon-gamma production by spleen cells, and mice immunized with TSP-Aq antigens gave a significant reduction in M. tuberculosis CFU counts by 1.17-1.32 log10 CFU in the lungs and 1.31-2.08 log10 CFU in the spleen from 6 to 28 weeks. The degree of protection offered by TSP-Aq was comparable to that of CFP and of the BCG vaccine. The results demonstrated that the TSP-Aq antigens confer a significant level of protection against the growth of the organism in the lungs and spleen in a mouse model of TB and indicate that TSP contains major protective antigens of M. tuberculosis.
Assuntos
Proteínas de Bactérias/imunologia , Parede Celular/imunologia , Mycobacterium tuberculosis/imunologia , Octoxinol , Vacinas contra a Tuberculose/imunologia , Tuberculose Pulmonar/prevenção & controle , Animais , Proteínas de Bactérias/administração & dosagem , Bovinos , Parede Celular/química , Células Cultivadas , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Mycobacterium bovis/imunologia , Solubilidade , Vacinas contra a Tuberculose/administração & dosagem , Tuberculose Pulmonar/imunologiaRESUMO
We report a case of an incidental nodular calcification of the alar ligament simulating a fracture in the craniovertebral junction of a previously healthy 24-year-old man. Three-dimensional CT and MR imaging revealed a 7.2 x 7.6 x 4.0 mm nodular calcification in the right alar ligament with normal adjacent bony structures. Serial cervical dynamic radiographs and open-mouth views showed that the cervical spine was stable without any change in the calcification.
Assuntos
Calcinose/diagnóstico , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Ligamentos Articulares/patologia , Imageamento por Ressonância Magnética , Osso Occipital/lesões , Processo Odontoide/lesões , Fraturas da Coluna Vertebral/diagnóstico , Tomografia Computadorizada por Raios X , Adulto , Concussão Encefálica/diagnóstico , Diagnóstico Diferencial , Humanos , Masculino , Osso Occipital/patologia , Processo Odontoide/patologia , Fraturas Orbitárias/diagnóstico , Fraturas Cranianas/diagnósticoRESUMO
Primary confluent cultures of retinal pigment epithelium (RPE) cells harvested from porcine eyes were challenged with latex spheres. The extracellular release of tissue plasminogen activator (t-PA) that was associated with phagocytosis of the beads by the RPE was measured by using enzyme-linked immunosorbent and chromogenic substrate assays. In the presence of serum and as compared to the controls, the phagocytosis of latex spheres produced a 5.5-fold increase in the amount of t-PA released into the ambient medium. Cell lysis was not a significant feature in either treated or control groups. Because the RPE in vivo is exposed to serum through the fenestrated choriocapillaris, and because phagocytosis by the RPE outer segments shed by the photoreceptors contributes to the maintenance of the functional integrity of the neural retina, we suggest that the release of t-PA associated with the phagocytic activity of RPE cells is an important physiologic event.
Assuntos
Fagocitose/fisiologia , Epitélio Pigmentado Ocular/fisiologia , Ativador de Plasminogênio Tecidual/metabolismo , Animais , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Látex , Epitélio Pigmentado Ocular/metabolismo , SuínosRESUMO
Nitric oxide (NO) is emerging as a very important and ubiquitous gaseous messenger in the body. The response characteristics of NO sensors made of non-conducting polymer modified carbon fiber electrodes are investigated to determine their selectivity, sensitivity, and stability for in vivo use. A composite polymer, comprising Nafion, m-phenylenediamine, and resorcinol, showed the best selectivity and stability to amperometric NO detection. The non-conducting, self-limiting polymer film protects the electrode from interference and fouling by other biochemicals. Although the relative sensitivity to NO of the modified sensor is lower than that of the unmodified carbon fiber electrodes (less than 6%), the composite polymer electrode showed high selectivity against ascorbic acid (> 2000:1), nitrite (> 600:1), and dopamine (> 200:1). The stability of the NO sensor was maintained for at least 1 week. The NO sensitivity after in vivo experiments (n = 8) is 88.1 +/- 5.6% of initial sensitivity data obtained before in vivo experiments. Preliminary in vivo experiments done with this electrode are shown to capture elevated NO levels in brain following an ischemic injury.
Assuntos
Técnicas Biossensoriais , Óxido Nítrico/análise , Animais , Carbono , Eletroquímica , Eletrodos , Polímeros de Fluorcarboneto/farmacologia , Masculino , Penicilamina/análogos & derivados , Penicilamina/farmacologia , Fenilenodiaminas/farmacologia , Ratos , Ratos Wistar , Resorcinóis/farmacologia , S-Nitroso-N-Acetilpenicilamina , Sensibilidade e EspecificidadeRESUMO
Bovine serum albumin (BSA), a model protein drug, was encapsulated with a microparticle based on the blend of poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactide)-g-oligo(ethylene glycol) (PLLA-g-oligoEG). Effects of PLLA-g-oligoEG in the blend on degradation, characteristic properties, and release behavior of the microparticle were studied. Drug loading efficiency increased with increase in the graft frequency of oligoEG in the graft copolymer in the blend. The release of BSA was found to be more efficient for microparticles based on the blend than on the PLGA, which is due to the faster protein diffusion through the swollen phase of the hydrogel-like structure. The microparticles based on the blend showed a slower degradation and a lower pH shift compared to that of PLGA.
Assuntos
Ácido Láctico/química , Ácido Poliglicólico/química , Polímeros/química , Proteínas/química , Varredura Diferencial de Calorimetria , Portadores de Fármacos , Microscopia de Força Atômica , Microesferas , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Desnaturação Proteica , Proteínas/administração & dosagem , Soroalbumina Bovina/química , Água/químicaRESUMO
BACKGROUND: To achieve a more reliable way of transplanting cardiomyocytes, we conducted an autologous cardiomyocyte transplantation using a biodegradable scaffold, instead of a syringe injection, as a vehicle for transporting cells in an ovine myocardial infarction model. MATERIALS AND METHODS: A myocardial infarction was created in sheep using sequential ligation of the homonymous artery and its diagonal branch. Autologous cardiomyocytes from the right ventricular infundibulum were cultured and seeded onto a biodegradable polymer scaffold. Three months after creating myocardial infarction, the two animals were re-anesthetized and cardiomyocyte-seeded scaffolds were implanted in the infarcted area. The animals were kept alive for a further month, and then sacrificed for postmortem heart examinations. Light microscopic analysis and an immunohistochemical study for myoglobin were performed. RESULTS: On postmortem gross examinations, the polymer scaffolds were visible in the background of well-demarcated thin-walled anteroseptal myocardial infarcts. Microscopic analysis showed abundant myoglobin-stained cells between the fiber strands of the polymer scaffolds. However, there is a possibility that some of these cells might have been giant cells reacting to foreign material. CONCLUSION: The transplantation of cultured autologous cardiomyocytes into an infarct region using a biodegradable scaffold instead of syringe injection provides another promising option for cardiomyocyte transplantation, which warrants further study.
Assuntos
Infarto do Miocárdio/cirurgia , Miócitos Cardíacos/transplante , Ácido Poliglicólico , Animais , Biodegradação Ambiental , Transplante de Células/instrumentação , Transplante de Células/métodos , Células Cultivadas/transplante , Modelos Animais de Doenças , Infarto do Miocárdio/complicações , Infarto do Miocárdio/patologia , Ovinos , Transplante AutólogoRESUMO
BACKGROUND: Tissue-engineered heart valve leaflets are a promising way to overcome the inherent limitations of current prosthetic valves. The aim of this study was to compare the biological responses of an autologous cell seeded scaffold and an acellular scaffold implanted in the pulmonary valve leaflet in the same animal. METHODS: Myofibroblasts and endothelial cells were isolated and cultured from an ovine artery. A synthetic biodegradable scaffold consisting of polyglycolic acid and polylactic acid was initially seeded with the myofibroblasts, then coated with endothelial cells. Cells were seeded using a medium containing collagen and cultured. A tissue-engineered construct and a plain scaffold were implanted as double pulmonary valve leaflet replacement in the same animal in an ovine model (n=3). Additionally, the tissue-engineered construct (n=2) and the plain scaffold (n=2) were implanted as single valve leaflet replacements for long-term analysis. After sacrifice, the implanted valve leaflet tissues were retrieved, analyzed visually and using light microscopy. RESULTS: Three animals that underwent replacement of two valve leaflets with a tissue-engineered construct and a plain scaffold, survived only a short-time (12, 24, 36 hours). The death was attributed to heart failure caused by severe pulmonary insufficiency. Animals that underwent single valve leaflet replacement survived longer and were electively sacrificed at 6 and 9 weeks after operation. The analysis of the leaflets from the short-term survivors showed that the tissue-engineered constructs contained less fibrins and protein exudates than the plain scaffold. In contrast, leaflets obtained from animals surviving 6 and 9 weeks showed similar well organized granulation tissues in the tissue-engineered constructs and the plain scaffolds. CONCLUSION: This animal experiment demonstrates that in the early phase of implantation, the tissue-engineered construct shows a better biological response in terms of antithrombogenicity than the plain scaffold, although both of them have similar results in the later reparative phase.
Assuntos
Valvas Cardíacas , Engenharia Tecidual , Animais , Células Cultivadas , Ecocardiografia Doppler em Cores , Valvas Cardíacas/diagnóstico por imagem , Masculino , Membranas Artificiais , Polímeros , OvinosRESUMO
BACKGROUND: A precondition for the successful formation of tissue-engineered heart valves is the generation of a proper matrix on biodegradable scaffolds over a limited period of time. The aim of this study was to find an effective method of seeding autologous cells on these scaffolds to create a new matrix for heart valves. METHODS: Myofibroblasts and endothelial cells were isolated and cultured from an ovine artery. A synthetic biodegradable scaffold consisting of polyglycolic and polylactic acids was seeded first with the myofibroblasts, then coated with endothelial cells. Three different methods of myofibroblast seeding were compared: I) daily seeding of myofibroblasts (1x10(6)) for ten days and culture for four days; II) seeding of myofibroblasts (1x10(7)) and culture for 14 days with the use of a simple medium; III) seeding of myofibroblasts (1x10(7)) with the use of a medium containing collagen and culture for 14 days. Light and electron microscopic analyses were performed. RESULTS: The group that used the medium containing collagen showed the best results in terms of seeding efficiency. CONCLUSION: Seeding autologous cells with a medium containing collagen onto the scaffold showed the largest cell population and might generate the best matrix on the scaffold.
Assuntos
Órgãos Bioartificiais , Endotélio Vascular/citologia , Próteses Valvulares Cardíacas , Músculo Liso Vascular/citologia , Implantes Absorvíveis , Animais , Células Cultivadas , Artéria Femoral , Fibroblastos , Ácido Láctico , Teste de Materiais , Poliésteres , Ácido Poliglicólico , Polímeros , Desenho de Prótese , OvinosRESUMO
It was demonstrated that glycogen-accumulating organisms (GAOs) were able to compete with phosphorus-accumulating organisms (PAOs) for acetate in a biological phosphorus removal (BPR) process, leading to a loss of BPR capability. Cellular fatty acid composition, which serves as a fingerprint for microbial identification, was used to determine microbial population change and to investigate the competition mechanisms of PAOs and GAOs. Analysis of cellular fatty acid composition indicated that PAOs grown with acetate and glucose were different species and that GAOs and PAOs grown with the same substrate were also different species. Glycogen-accumulating organisms seemed to coexist with PAOs even in a well-developed BPR process. The GAOs were able to accumulate more poly-beta-hydroxybutyrate (PHB) and glycogen than PAOs during the anaerobic stage of the BPR process. The GAOs synthesized more in-cell glycogen than PAOs. The growth rate for PAOs was always greater than that for GAOs at various acetate or glucose concentrations, while GAOs had higher acetate uptake and PHB synthesis rates than PAOs. Therefore, GAOs are thought to compete with PAOs only at long solids retention times (> or = 20 days).
Assuntos
Ácidos Graxos/análise , Ácidos Graxos/química , Glicogênio/farmacocinética , Fósforo/farmacocinética , Bactérias , Biodegradação Ambiental , Glucose/metabolismo , Glicogênio/metabolismo , Hidroxibutiratos/metabolismo , Hidroxibutiratos/farmacocinética , Cinética , Fósforo/metabolismo , Poliésteres/metabolismo , Poliésteres/farmacocinética , Dinâmica Populacional , Microbiologia da ÁguaRESUMO
Markets for scrap tires have expanded since the early 1990s with the development of value-added applications such as tire-derived fuel and crumb-rubber-amended asphalt. Granulated tires have also displayed the ability to adsorb volatile organic compounds, indicating that the rubber material can be a useful filter media. Sand-based root zones, typically used for golf course putting green and athletic field construction, lack sufficient cation exchange capacity to restrict nitrogen and phosphorus migration through the root zone and into sub-surface drainage systems. Therefore, the adsorptive properties of tire rubber for retaining nitrogen and phosphorus were studied when applied as a distinct sub-surface drainage or intermediate layer in golf course putting greens. A statistically significant reduction in the concentration of nitrate in leachate was achieved by replacing traditional pea gravel with equally sized granulated tires for the drainage layer media, although the mechanism of nitrate mitigation remains unclear. The results indicate that using granulated tires as a drainage layer or fill material beneath sand-based root zones does not compromise the function of the profile or quality of the vegetation while creating an environmentally beneficial and value-added option for scrap tire reuse.
Assuntos
Conservação dos Recursos Naturais , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Eliminação de Resíduos , Borracha , Biodegradação Ambiental , Filtração , Nitrogênio/análise , Fósforo/análise , Raízes de Plantas , Dióxido de Silício , Poluição da Água/prevenção & controleAssuntos
Histiocitoma Fibroso Benigno , Neoplasias Bucais , Idoso , Feminino , Histiocitoma Fibroso Benigno/diagnóstico , Histiocitoma Fibroso Benigno/patologia , Histiocitoma Fibroso Benigno/cirurgia , Humanos , Soalho Bucal , Neoplasias Bucais/diagnóstico , Neoplasias Bucais/patologia , Neoplasias Bucais/cirurgiaRESUMO
The in vitro response of the mouse fibroblast cell line 3T3 on the surface of ultrafine grained titanium [produced by a severe plastic deformation (SPD) process] has been studied in this work. SPD Ti showed much higher strength than the coarse grained Ti and equivalent to that of Ti-6Al-4V alloy. Better cell proliferation was observed on SPD Ti compared to conventional Ti and Ti-6Al-4V alloy. This could be attributed to the increased surface free energy by reduction in the grain size and possibly the presence of a large number of nano size grooves at the triple point junctions in SPD Ti sample. There was no significant difference in the results of cytotoxicity tests of fine and coarse grained materials.
Assuntos
Fibroblastos/efeitos dos fármacos , Titânio/química , Células 3T3 , Animais , Materiais Biocompatíveis , Proliferação de Células , Teste de Materiais , Camundongos , Tamanho da Partícula , Próteses e Implantes , Estresse MecânicoRESUMO
This work attempts to understand the in vitro biocompatibility of ultrafine grained titanium prepared by the ECAP route. The results obtained from the mouse fibroblast cell line 3T3 showed a better cell adherence and cell proliferation on ECAP titanium specimen compared to the coarse grain Grade-2 Ti and Ti6Al4V alloy. This could be attributed to the increased surface energy and grain boundary energy and possibly the presence of a large number of nano-size conical groove-like structures (at triple point junctions of grain boundaries on the surface) in the ECAP Ti specimen compared to the coarse grain Grade-2 Ti and Ti6Al4V alloy.