Experimental system for studying temperature gradient-driven fracture of oxide nuclear fuel out of reactor.

Temperature gradients in ceramic light water reactor (LWR) uranium dioxide (UO2) nuclear fuel pellets generate thermal stresses that cause fractures in the fuel, which begins early in the life of fresh fuel. The combination of heating due to fission and forced convective cooling on the exterior of LWR fuel rods generates a temperature profile that is difficult to replicate outside the reactor environment. In this study, a state-of-the-art experimental setup using electrical heating to study certain aspects of temperature driven fracture was built, and surrogate fuel materials such as ceria (CeO2) were used to validate the system. Cracking experiments were conducted on these surrogates by inducing reactivity-initiated-accident like temperature gradients in the pellets via induction and direct resistance heating. Induction heating was done using copper coils and molybdenum susceptors, which heated the surrogates to a threshold temperature that is sufficiently high for the fuel material to conduct current. Thereafter, direct resistance heating was achieved by passing current through the specimen using a DC power supply to introduce volumetric heating to replicate LWR operating conditions. The pellets were held against nickel electrodes and mounted on a boron nitride test-stand. All the tests were carried out in a stainless-steel vacuum chamber. Simultaneous real-time dual imaging of the surrogate pellet surface was implemented using an optical and infrared camera system that was mounted along axial and perpendicular directions to the pellet surface, respectively. A beam-splitter was used to split the incoming radiation from the sample into two halves. While one of the beams was transmitted from the splitter through a bandpass filter to obtain optical images, the other beam was reflected from the splitter to the thermal camera to capture full-field temperature gradients of the as-fabricated pellet surface during cracking. Some initial tests were conducted with a 2-color pyrometer that was later substituted with a forward-looking infrared thermal camera to capture the temperature profiles. A LabVIEW data acquisition system was set up for collecting useful data during experiments.

Presença de Campylobacter spp. em macacos-de-cheiro (Saimiri spp.) assintomáticos cativos e sua correlação com as condições de manejo / Campylobacter spp. in asymptomatic captive squirrel monkeys (Saimiri spp.) and its correlation with the handling conditions

Avaliou-se a circulação de Campylobacter spp. em uma criação de primatas neotropicais macacos-de-cheiro (Saimiri spp.), clinicamente saudáveis, utilizados em investigações biomédicas. A análise foi feita no decorrer de sete anos não consecutivos, de 1995 a 1999, 2002 e 2003. Os resultados revelaram um maior índice de positividade no ano de 1996, em contraste com a ausência do agente em 2003. Os dados sugerem que as alterações realizadas no manejo animal, ao longo deste estudo, foram eficazes para a eliminação do Campylobacter spp. na criação de macacos-de-cheiro, levando os animais a uma melhor qualidade de vida e, consequentemente, obtendo-se um melhor produto para fins de pesquisas.

The circulation of Campylobacter spp. in a breeding colony of clinically healthy neotropical primates squirrel monkeys (Saimiri spp.) used in biomedical investigation was evaluated. Analyses were undertaken during seven non-consecutive years: 1995 to 1999, 2002 and 2003. Results revealed a higher rate of positivity in 1996, in contrast to the absence of the agent in 2003. The data suggest that the changes made in the animal management during this study were effective for the Campylobacter spp. elimination of the squirrel monkeys breeding colony, leading to a better quality of life and, hence, resulting in a better animal for research.

Effects of sample re-sequencing and trimming on the quality and size of assembled consensus sequences.

The production of nucleic acid sequences by automatic DNA sequencer machines is always associated with some base-calling errors. In order to produce a high-quality DNA sequence from a molecule of interest, researchers normally sequence the same sample many times. Considering base-calling errors as rare events, re-sequencing the same molecule and assembling the reads produced are frequently thought to be a good way to generate reliable sequences. However, a relevant question on this issue is: how many times the sample needs to be re-sequenced to minimize costs and achieve a high-fidelity sequence? We examined how both the number of re-sequenced reads and PHRED trimming parameters affect the accuracy and size of final consensus sequences. Hundreds of single-pool reaction pUC18 reads were generated and assembled into consensus sequences with CAP3 software. Using local alignment against the published pUC18 cloning vector sequence, the position and number of errors in the consensus were identified and stored in MySQL databases. Stringent PHRED trimming parameters proved to be efficient for the reduction of errors; however, this procedure also decreased consensus size. Moreover, re-sequencing did not have a clear effect on the removal of consensus errors, although it was able to slightly increase consensus.

Low-level-laser therapy as an alternative treatment for primary herpes simplex infection: a case report.

Gingivostomatitis is the most common primary and symptomatic clinical manifestation of HSV-1 infection. Painful oral lesions appear as ulcerative erosions on the gingiva, palate, buccal mucosa, and tongue, leading to eating and drinking difficulties with an evolution between 10-14 days. This paper describes a case of a 19-month-old boy with severe painful Gingivostomatitis lesions. Low level laser therapy (LLLT) was used with an immediate outcome.

Effects of sample re-sequencing and trimming on the quality and size of assembled consensus sequences

The production of nucleic acid sequences by automatic DNA sequencer machines is always associated with some base-calling errors. In order to produce a high-quality DNA sequence from a molecule of interest, researchers normally sequence the same sample many times. Considering base-calling errors as rare events, re-sequencing the same molecule and assembling the reads produced are frequently thought to be a good way to generate reliable sequences. However, a relevant question on this issue is: how many times the sample needs to be re-sequenced to minimize costs and achieve a high-fidelity sequence? We examined how both the number of re-sequenced reads and PHRED trimming parameters affect the accuracy and size of final consensus sequences. Hundreds of single-pool reaction pUC18 reads were generated and assembled into consensus sequences with CAP3 software. Using local alignment against the published pUC18 cloning vector sequence, the position and number of errors in the consensus were identified and stored in MySQL databases. Stringent PHRED trimming parameters proved to be efficient for the reduction of errors; however, this procedure also decreased consensus size. Moreover, re-sequencing did not have a clear effect on the removal of consensus errors, although it was able to slightly increase consensus.