Piezoresistive response of ITO films deposited at room temperature by magnetron sputtering

Indium tin oxide (ITO) thin films have been deposited on (100) Si substrates by RF magnetron sputtering from a compact target (90% In(2)O(3)-10% SnO(2) in weight) with 6 in. in diameter. In order to perform electromechanical characterizations of these films, strain gauges were fabricated. An experimental set-up based on bending beam theory was developed to determine the longitudinal piezoresistive coefficient (pi(1)) of the strain gauges fabricated. It has been confirmed that electrical resistance of the strain gauges decreases with load increases which results a negative gauge factor. A model based on the activation energy was used to explain the origin of this negative signal. The influence of the temperature on piezoresistive properties of ITO films was also evaluated.

Absorption and emission properties of LBL PPV films deposited on ITO electrodes

In this work we studied the properties of absorption and emission line shape of layer-by-layer (LBL) poly(p-phenylene vinylene) (PPV) on indium-tin oxide (ITO) electrode. To minimize the PPV thermal conversion effects during the polymer processing, we used a less aggressive leaving group in the precursor polymer; minimizing electrode degradation. LBL ITO/PPV films showed the same absorption and emission line shape compared with LBL PPV films deposited on non-metallic substrates (glass). With this analysis we indirectly observe the decrease in the ITO degradation. Atomic force microscopy (AFM) technique was used to analyze quantitatively the microscopic morphology of the film surface. Results indicated that the substrate topology is not affected, to a large extent, by the use of dodecylbenzensulfonate (DBS) ion. (C) 2008 Elsevier B.V. All rights reserved.

Antibacterial activity of root canal filling materials for primary teeth: zinc oxide and eugenol cement, Calen paste thickened with zinc oxide, Sealapex and EndoREZ

This study evaluated in vitro the antibacterial activity of 4 root canal filling materials for primary teeth - zinc oxide and eugenol cement (ZOE), Calen paste thickened with zinc oxide (Calen/ZO), Sealapex sealer and EndoREZ sealer - against 5 bacterial strains commonly found in endodontic infections (Kocuria rhizophila, Enterococcus faecalis, Streptococcus mutans, Escherichia coli and Staphylococcus aureus) using the agar diffusion test (agar-well technique). Calen paste, 1% chlorhexidine digluconate (CHX) and distilled water served as controls. Seven wells per dish were made at equidistant points and immediately filled with the test and control materials. After incubation of the plates at 37oC for 24 h, the diameter of the zones of bacterial growth inhibition produced around the wells was measured (in mm) with a digital caliper under reflected light. Data were analyzed statistically by analysis of variance and Tukey's post-hoc test (?=0.05). There were statistically significant differences (p<0.0001) among the zones of bacterial growth inhibition produced by the different materials against all target microorganisms. K. rhizophila was inhibited more effectively (p<0.05) by ZOE, while Calen/ZO had its highest antibacterial activity against E. faecalis (p<0.05). S. mutans was inhibited by Calen/ZO, Sealapex and ZOE in the same intensity (p>0.05). E. coli was inhibited more effectively (p<0.05) by ZOE, followed by Calen/ZO and Sealapex. Calen/ZO and ZOE were equally effective (p>0.05) against S. aureus, while Sealapex had the lowest antibacterial efficacy (p<0.05) against this microorganism. EndoREZ presented antibacterial activity only against K. rhizophila and S. aureus. The Calen paste and Calen/ZO produced larger zones of inhibition than 1% CHX when the marker microorganism was E faecalis. In conclusion, the in vitro antibacterial activity of the 4 root canal filling materials for primary teeth against bacterial strains commonly found in endodontic infections can be presented in a decreasing order of efficacy as follows: ZOE>Calen/ZO>Sealapex>EndoREZ.

Microbial distribution in the root canal system after periapical lesion induction using different methods

The aim of this study was to evaluate the microbial distribution in the root canal system after periapical lesion induction in dogs' teeth using different methods. Fifty-two root canals were assigned to 4 groups (n=13). Groups I and II: root canals were exposed to the oral cavity for 180 days; groups III and IV: root canals were exposed for 7 days and then the coronal openings were sealed for 53 days. The root apices of groups I and III were perforated, while those of groups II and IV remained intact. After the experimental periods, the animals were euthanized and the anatomic pieces containing the roots were processed and stained with the Brown & Brenn method to assess the presence and distribution of microorganisms. The incidence of microorganisms at different sites of the roots and periapical lesions was analyzed statistically by the chi-square test at 5% significance level. All groups presented microorganisms in the entire root canal system. A larger number of microorganisms was observed on the root canal walls, apical delta and dentinal tubules (p<0.05), followed by cementum and cemental resorption areas. In spite of the different periods of exposure to the oral environment, the methods used for induction of periapical periodontitis yielded similar distribution of microorganisms in the root canal system.

Prevalence of mutans streptococci isolated from complete dentures and their susceptibility to mouthrinses

The aims of this study were to evaluate the incidence of mutans streptococci (MS - sessile form) on complete maxillary dentures after use of a specific denture paste, and to determine the minimum inhibitory concentration (MIC) and maximum inhibitory dilution (MID) of 3 oral mouthrinses: Cepacol, Plax and Periogard. Seventy-seven complete denture wearers were randomly assigned into 2 groups, according to the product used for denture cleaning: Control group - conventional dentifrice (Kolynos-Super White); and Test group: experimental denture cleaning paste. Denture biofilm was collected at baseline and after 90 and 180 days after treatment by brushing the dentures with saline solution. After decimal serial dilution, samples were seeded onto agar sucrose bacitracin to count colonies with morphological characteristics of MS. MS identification was performed by the sugar fermentation tests. After this procedure, brain heart infusion broth (BHI) was added to oral mouthrinses (Plax, Cepacol e Periogard) and seeded on Petri dishes. The colonies were seeded using the Steers multiplier and, after the incubation, the MIC and MID of the mouthrinses were calculated. The results showed an incidence of 74.0% (n=57) of MS in the 77 complete dentures examined in the study, being 76.3% (n=29) of the Control group (conventional dentifrice) and 71.8% (28) of the Test group (experimental denture cleaning paste). In both groups, the number of positive cases for MS decreased from day 0 to day 180. In the Test group there was a slight decrease in the incidence of Streptococcus mutans 90 days after use of the experimental denture cleaning paste, which was not observed in the Control group. As regards to mouthrinses, for both groups, Periogard showed antimicrobial action with the highest dilution, followed by Cepacol and Plax. In conclusion, the incidence of MS in complete dentures was high and Periogard was the mouthrinse with the strongest antimicrobial action against MS. The experimental denture cleaning paste showed a slight action against S. mutans after 90 days of treatment.

Clinical and antimicrobial efficacy of NitrAdineTM-based disinfecting cleaning tablets in complete denture wearers

OBJECTIVE: This study evaluated the efficacy of NitrAdineTM-based disinfecting cleaning tablets for complete denture, in terms of denture biofilm removal and antimicrobial action. MATERIAL AND METHODS: Forty complete denture wearers (14 men and 26 women) with a mean age of 62.3±9.0 years were randomly assigned to two groups and were instructed to clean their dentures according to two methods: brushing (control) - 3 times a day with denture brush and tap water following meals; brushing and immersion (Experimental) - brushing the denture 3 times a day with denture brush and tap water following meals and immersion of the denture in NitrAdineTM-based denture tablets (Medical InterporousTM). Each method was used for 21 days. Denture biofilm was disclosed by a 1% neutral red solution and quantified by means of digital photos taken from the internal surface before and after the use of the product. Microbiological assessment was conducted to quantify Candida sp. RESULTS: An independent t-test revealed a significant lower biofilm percentage for the experimental group (4.7, 95% CI 2.4 to 7.9) in comparison with the control group (mean 37.5, 95% CI 28.2 to 48.1) (t38=7.996, p<0.001). A significant reduction of yeast colony forming units could be found after treatment with Medical InterporousTM denture tablets as compared to the control group (Mann-Whitney test, Z=1.90; p<0.05). CONCLUSION: The present findings suggest that NitrAdineTM-based disinfecting cleaning tablets are efficient in removal of denture biofilm. In addition, a clear antimicrobial action was demonstrated. Therefore, they should be recommended as a routine denture maintenance method for the prevention of the development of microbial biofilm induced denture stomatitis.

Antimicrobial efficacy of chemical disinfectants on contaminated full metal crowns

Prosthetic restorations that have been tried in the patient's mouth are potential sources of infection. In order to avoid cross-infection, protocols for infection control should be established in dental office and laboratory. This study evaluated the antimicrobial efficacy of disinfectants on full metal crowns contaminated with microorganisms. Full crowns cast in a Ni-Cr alloy were assigned to one control group (n=6) and 5 experimental groups (n=18). The crowns were placed in flat-bottom glass balloons and were autoclaved. A microbial suspension of each type of strain - S. aureus, P. aeruginosa, S. mutans, E. faecalis and C. albicans- was aseptically added to each experimental group, the crowns being allowed for contamination during 30 min. The contaminated specimens were placed into recipients with the chemical disinfectants (1% and 2% sodium hypochlorite and 2% glutaraldehyde) for 5, 10 and 15 min. Thereafter, the crowns were placed into tubes containing different broths and incubated at 35ºC. The control specimens were contaminated, immersed in distilled water for 20 min and cultured in Thioglycollate broth at 35ºC. Microbial growth assay was performed by qualitative visual examination after 48 h, 7 and 12 days. Microbial growth was noticed only in the control group. In the experimental groups, turbidity of the broths was not observed, regardless of the strains and immersion intervals, thus indicating absence of microbial growth. In conclusion, all chemical disinfectants were effective in preventing microbial growth onto full metal crowns.

Maximum inhibitory dilution of mouthwashes containing chlorhexidine and polyhexamethylene biguanide against salivary staphylococcus aureus

OBJECTIVE: The aim of the present study was to determine the in vitro maximum inhibitory dilution (MID) of two chlorhexidinebased oral mouthwashes (CHX): Noplak®, Periogard®, and one polyhexamethylene biguanide-based mouthwash (PHMB): Sanifill Premium® against 28 field Staphylococcus aureus strains using the agar dilution method. MATERIALS AND METHODS: For each product, decimal dilutions ranging from 1/10 to 1/655,360 were prepared in distilled water and added to Mueller Hinton Agar culture medium. After homogenization, the culture medium was poured onto Petri dishes. Strains were inoculated using a Steers multipoint inoculator and dishes were incubated at 37ºC for 24hours. For reading, MID was considered as the maximum dilution of the mouthwash still capable of inhibiting microbial growth. RESULTS: Sanifill Premium® inhibited the growth of all strains at 1/40 dilution and of 1 strain at 1/80 dilution. Noplak® inhibited the growth of 23 strains at 1/640 dilution and of all 28 strains at 1/320 dilution. Periogard® showed inhibited growth of 7 strains at 1/640 dilution and of all 28 strains at 1/320 dilution. Data were submitted to Kruskal-Wallis statistical test, showing significant differences between the mouthwashes evaluated (p<0.05). No significant difference was found between Noplak® and Periogard® (p>0.05). Sanifill Premium® was the least effective (p<0.05). CONCLUSION: It was concluded that CHX-based mouthwashes present better antimicrobial activity against S. Aureus than the PHMB-based mouthwash.

Determination of the maximum inhibitory dilution of cetylpyridinium chloride-based mouthwashes against staphylococcus aureus: an in vitro study

The aim of this in vitro study was to determine the maximum inhibitory dilution (MID) of four cetylpyridinium chloride (CPC)-based mouthwashes: CPC+Propolis, CPC+Malva, CPC+Eucaliptol+Juá+Romã+Propolis (Natural Honey®) and CPC (Cepacol®), against 28 Staphylococcus aureus field strains, using the agar dilution method. Decimal dilutions ranging from 1/10 to 1/655,360 were prepared and added to Mueller Hinton Agar. Strains were inoculated using Steers multipoint inoculator. The inocula were seeded onto the surface of the culture medium in Petri dishes containing different dilutions of the mouthwashes. The dishes were incubated at 37ºC for 24 h. For readings, the MID was considered as the maximum dilution of mouthwash still capable of inhibiting microbial growth. The obtained data showed that CPC+Propolis had antimicrobial activity against 27 strains at 1/320 dilution and against all 28 strains at 1/160 dilution, CPC+Malva inhibited the growth of all 28 strains at 1/320 dilution, CPC+Eucaliptol+Juá+Romã+Propolis inhibited the growth of 2 strains at 1/640 dilution and all 28 strains at 1/320 dilution, and Cepacol® showed antimicrobial activity against 3 strains at 1/320 dilution and against all 28 strains at 1/160 dilution. Data were submitted to Kruskal-Wallis test, showing that the MID of Cepacol® was lower than that determined for the other products (p<0.05). In conclusion, CPC-mouthwashes showed antimicrobial activity against S. aureus and the addition of other substances to CPC improved its antimicrobial effect.

Antibacterial activity of four mouthrinses containing triclosan against salivary Staphylococcus aureus

The maximum inhibitory dilution (MID) of triclosan-based mouthwashes against 28 Staphylococcus aureus strains was evaluated. Dilutions ranging from 1/10 to 1/655,360 were prepared. Strains were inoculated using a Steers multipoint inoculator. The MID was considered as the maximum dilution capable of inhibiting microorganism growth. The mouthwashes presented different MIDs.

Vitaminas D e C para poedeiras na fase inicial de produção de ovos

Um experimento foi conduzido com o objetivo de avaliar os efeitos de duas fontes de vitamina D e três níveis de vitamina C sobre as características de desempenho, a qualidade interna e externa dos ovos, os níveis de cálcio total e iônico séricos e a resistência óssea de poedeiras. Foram utilizadas 288 galinhas da linhagem ISA Babcock B300® com 23 semanas de idade, durante um período experimental de 12 semanas. Utilizou-se o delineamento inteiramente ao acaso em arranjo fatorial 2 × 3, com os fatores: fontes de vitamina D (colecalciferol e 25-hidroxicolecalciferol - 25(OH)D3) e de vitamina C (0, 100 e 200 ppm), totalizando seis tratamentos com oito repetições de seis aves. O nível basal de colecalciferol foi de 2.756 UI/kg, correspondendo a 5,51 g do produto comercial Hy.D®/t de ração, como fonte de 25(OH)D3. Os fatores estudados não influenciaram o consumo de ração, a produção, o peso e a massa de ovos. Observou-se efeito da interação de fontes de vitamina sobre a conversão alimentar, que foi melhor quando utilizado metabólito 25(OH)D3 na ausência de vitamina C. Interações foram observadas para porcentagem de albúmen e porcentagem de gema, que aumentaram na presença de 200 ppm de vitamina C. O peso específico dos ovos, as concentrações de cálcio sérico, cinzas ósseas e a resistência à quebra não foram influenciadas pelas fontes de vitamina D e C. Houve interação para porcentagem e espessura de casca, cujos maiores valores foram obtidos com a suplementação de vitamina C na presença de 25(OH)D3. Em poedeiras na fase inicial de produção, a conversão alimentar é melhor com a utilização do 25(OH)D3 e a espessura e porcentagem de casca também melhoram com a utilização de 25(OH)D3 e a suplementação de vitamina C nas dietas (100 ou 200 ppm, respectivamente).

Extensão máxima de retalho pediculado de omento maior através de túnel subcutâneo para ossos longos em cães

Há tempo sabe-se que o omento humano pode promover atividade angiogênica em estruturas adjacentes nas quais ele é aplicado. Na medicina veterinária, são poucas as pesquisas com retalho pediculado de omento maior como indutor angiogênico e imunogênico, porém suas propriedades de adesão e drenagem são bem conhecidas. Os objetivos deste estudo foram criar um retalho pediculado de omento maior, mensurar seu comprimento durante as etapas de criação e avaliar a possibilidade de alcance para ossos longos (fêmur, tíbia, úmero, rádio e ulna) através de túnel subcutâneo, visando a utilizá-lo futuramente como indutor angiogênico em focos de fratura, para aceleração da osteogênese e controle de infecções ósseas. Foram utilizados 30 cadáveres frescos de cães de todas as raças, com exceção dos condrodistróficos. Os resultados foram conclusivos e confirmaram a possibilidade de alcance do retalho de omento para ossos longos de cadáveres de cães em que todos os retalhos alcançaram a metáfise distal dos ossos avaliados. A média de comprimento do omento, em camada dupla, dos 30 animais avaliados foi de 30,87cm; da camada simples foi de 54,37cm e do retalho em L foi de 92,7cm. Com a extensão máxima do omento, foi possível alcançar as metáfises distais de todos os ossos propostos, com comprimento médio excedente de 29,87cm para fêmur, 20,73cm para tíbia/fíbula, 25,13cm para úmero e 16,27cm para rádio/ulna. As variáveis peso e retalho em L avaliadas estatisticamente de cada indivíduo apresentaram correlação positiva moderada. Concluiu-se que, em cadáveres de cães, é possível levar o retalho pediculado de omento maior através de túnel subcutâneo para metáfise distal de ossos longos e que, quanto maior o peso do animal, maior o comprimento do retalho em L.

Pathogenicity of different rabies virus isolates and protection test in vaccinated mice

This study was aimed to evaluate and compare the pathogenicity of rabies virus isolated from bats and dogs, and to verify the efficacy of a commercial rabies vaccine against these isolates. For evaluation of pathogenicity, mice were inoculated by the intramuscular route (IM) with 500MICLD50/0.03mL of the viruses. The cross-protection test was performed by vaccinating groups of mice by the subcutaneous route and challenged through the intracerebral (IC) route. Isolates were fully pathogenic when inoculated by the IC route. When inoculated intramuscularly, the pathogenicity observed showed different death rates: 60.0% for the Desmodus rotundus isolate; 50.0% for dog and Nyctinomops laticaudatus isolates; 40.0% for Artibeus lituratus isolate; 9.5% Molossus molossus isolate; and 5.2% for the Eptesicus furinalis isolate. Mice receiving two doses of the vaccine and challenged by the IC route with the isolates were fully protected. Mice receiving only one dose of vaccine were partially protected against the dog isolate. The isolates from bats were pathogenic by the IC route in mice. However, when inoculated through the intramuscular route, the same isolates were found with different degrees of pathogenicity. The results of this work suggest that a commercial vaccine protects mice from infection with bat rabies virus isolates, in addition to a canine rabies virus isolate.

Paralytic rabies in swine

Rabies transmitted by vampire bats was diagnosed in pigs with paralysis of the pelvic limbs. Diffuse nonsuppurative encephalomyelitis, affecting mainly the spinal cord, was observed histologically. Despite the various diagnosis of rabies in pigs this is the first report of clinical signs and pathology of rabies transmitted by vampire bats.

Isolation of rabies virus from the parotid salivary glands of foxes (Pseudalopex vetulus) from Paraíba State, Northeastern Brazil

To determine the presence of rabies virus in the parotid salivary glands, 12 road-killed rabies-positive hoary foxes (Pseudoalopex vetulus) were tested by using the fluorescent antibody test (FAT) and mouse inoculation test (MIT). All 12 parotid salivary glands were positive for both tests, although in some cases several passages were required. The findings of this study support the importance of the hoary fox as rabies reservoir in the semi-arid region of Paraíba State, Northeastern Brazil.