Optically transparent membrane based on bacterial cellulose/ polycaprolactone

Optically transparent membranes from bacterial cellulose (BC)/polycaprolactone (PCL) have been prepared by impregnation of PCL acetone solution into dried BC membranes. UV-Vis measurements showed an increase on transparency in BC/PCL membrane when compared with pristine BC. The good transparency of the BC/PCL can be related to the presence of BC nanofibers associated with deposit of PCL nano-sized spherulites which are smaller than the wavelength of visible light and practically free of light scattering. XRD results show that cellulose type I structure is preserved inside the BC/PCL membrane, while the mechanical properties suggested indicated that PCL acts as a plasticizer for the BC membrane. The novel BC/PCL membrane could be used for preparation of fully biocompatible flexible display and biodegradable food packaging.

Simple green approach to reinforce natural rubber with bacterial cellulose nanofibers

Natural rubber (NR) is a renewable polymer with a wide range of applications, which is constantly tailored, further increasing its utilizations. The tensile strength is one of its most important properties susceptible of being enhanced by the simple incorporation of nanofibers. The preparation and characterization of natural-rubber based nanocomposites reinforced with bacterial cellulose (BC) and bacterial cellulose coated with polystyrene (BCPS), yielded high performance materials. The nanocomposites were prepared by a simple and green process, and characterized by tensile tests, dynamical mechanical analysis (DMA), scanning electron microscopy (SEM), and swelling experiments. The effect of the nanofiber content on morphology, static, and dynamic mechanical properties was also investigated. The results showed an increase in the mechanical properties, such as Young's modulus and tensile strength, even with modest nanofiber loadings. © 2013 American Chemical Society.

ZnO nanostructures directly grown on paper and bacterial cellulose substrates without any surface modification layer

In this report, hierarchical ZnO nano- and microstructures were directly grown for the first time on a bacterial cellulose substrate and on two additional different papers by hydrothermal synthesis without any surface modification layer. Compactness and smoothness of the substrates are two important parameters that allow the growth of oriented structures. © 2013 The Royal Society of Chemistry.

Flexible magnetic membranes based on bacterial cellulose and its evaluation as electromagnetic interference shielding material

Flexible magnetic membranes with high proportion of magnetite were successfully prepared by previous impregnation of the never dried bacterial cellulose pellicles with ferric chloride followed by reduction with sodium bisulfite and alkaline treatment for magnetite precipitation. Membranes were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating magnetometer, field emission scanning electron microscopy (FEG-SEM) and impedance spectroscopy. Microwave properties of these membranes were investigated in the X-band (8.2 to 12.4 GHz). FEG-SEM micrographs show an effective coverage of the BC nanofibers by Fe 3O4 nanoparticles. Membranes with up to 75% in weight of particles have been prepared after 60 min of reaction. Magnetite nanoparticles in the form of aggregates well adhered to the BC fibers were observed by SEM. The average crystal sizes of the magnetic particles were in the range of 10 ± 1 to 13 ± 1 nm (estimated by XRD). The magnetic particles in the BC pellicles presented superparamagnetic behavior with a saturation magnetization in the range of 60 emu g- 1 and coercive force around 15 Oe. These magnetic pellicles also displayed high electrical permittivity and a potential application as microwave absorber materials. © 2013 Elsevier B.V.

Influence of experimental canine ehrlichiosis on the E-ADA activity and purine levels in serum and possible functional correlations with pathogenesis

The aim of this study was to evaluate adenosine deaminase activity and purines levels in serum of dogs experimentally infected by Ehrlichia canis. Banked serum samples of dogs divided into two groups with five animals each: healthy animals and animals infected by E. canis. The concentration of purines (adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), adenosine, inosine, hypoxanthine, xanthine and uric acid), and adenosine deaminase (E-ADA) activity in sera were evaluated. Samples were collected on days 12 and 30 post-infection (PI). The E-ADA activity showed a significant reduction on day 12 PI, and increased on day 30 PI in dogs infected with E. canis. On day 12, an increase in seric concentration of ATP, ADP and adenosine was verified, and different levels of hypoxanthine, xanthine and uric acid had a drastic reduction in infected compared healthy dogs (P< 0.05). However, on day 30 PI, the levels of seric ADP and AMP decreased, unlike the concentration of xanthine and uric acid that increased significantly in infected dogs (P< 0.05). Therefore, the activity of E-ADA and purine levels are altered in experimental canine ehrlichiosis, probably with the purpose of modulating the pathogenesis of the disease related to immune response, oxidative stress and coagulation disorders in acute phase. © 2013 Elsevier B.V.

Perfil genético e fenotípico de Staphylococcus sp isolados de leite de vacas saudáveis e com mastite

Pós-graduação em Biologia Geral e Aplicada - IBB

Efeito da quercetina sobre alguns fatores relacionados com a virulência de Staphylococcus aureus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Papel das proteínas intracelulares Nod e da proteína adaptadora MyD88 na regulação de espressão de RANKL e modulação da resposta inflamatória induzidos por antígenos bacterianos in vitro: estudo em células relevantes de periodonto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação dos efeitos de Streptococcus mutans sobre formação de biofilme e morfogênese de Candida albicans in vitro e estudo experimental em Galleria mellonella

Pós-graduação em Biopatologia Bucal - ICT

Caracterização das alterações teciduais em dois modelos de indução de doença periodontal experimental em camundongos

Pós-graduação em Odontologia - FOAR

Bacterial cellulose/triethanolamine based ion-conducting membranes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modular Hyperthermostable Bacterial Endo-beta-1, 4-Mannanase: Molecular Shape, Flexibility and Temperature-Dependent Conformational Changes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bacterial Pathogens Related to Chronic Suppurative Otitis Media in Individuals With Cleft Palate: Bacteriological Culture and Polymerase Chain Reaction

Objective: To characterize the microbial etiology of chronic suppurative otitis media comparing the methods of classical bacteriological culture and polymerase chain reaction.Design/Setting/Patients: Bacteriological analysis by classical culture and by molecular polymerase chain reaction of 35 effusion otitis samples from patients with cleft lip and palate attending the Hospital for Rehabilitation of Craniofacial Anomalies of the University of Sao Paulo, Bauru, Brazil.Interventions: Collection of clinical samples of otitis by effusion through the external auditory tube.Main Outcome Measure: Otolaryngologic diagnosis of chronic suppurative otitis media.Results: Positive cultures were obtained from 83% of patients. Among the 31 bacterial lineages the following were isolated. In order of decreasing frequency: Pseudomonas aeruginosa (54.9%), Staphylococcus aureus (25.9%), and Enterococcus faecalis (19.2%). No anaerobes were isolated by culture. The polymerase chain reaction was positive for one or more bacteria investigated in 97.1% of samples. Anaerobe lineages were detected by the polymerase chain reaction method, such as Fusobacterium nucleatum, Bacteroides fragilis, and Peptostreptococcus anaerobius.Conclusions: Patients with cleft lip and palate with chronic suppurative otitis media presented high frequency of bacterial infection in the middle ear. The classical bacteriological culture did not detect strict anaerobes, whose presence was identified by the polymerase chain reaction method.

New biphasic mono-component composite material obtained by partial oxypropylation of bacterial cellulose

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The enigmatic role of cholinergic reflex in the pathogenesis of Chagas disease

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)