1,603 research outputs found

    Facile synthesis of metal-organic framework films via in situ seeding of nanoparticles

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    A facile in situ nanoparticle seeding method is reported to prepare MIL-101(Cr) films on alumina supports. The in situ seeding of MIL-101(Cr) nanoparticles was promoted by use of dimethylacetamide (DMA). The generality of this approach is further demonstrated for Cu 3(btc) 2 films by using a (poly)acrylate promoter

    Salmonella immunization confers cross protection without confounding pre-harvest serologic monitoring

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    Food borne Salmonella Typhimurium is a valid concern for the global pork industry. An attenuated oral swine Salmonella Choleraesuis vaccine has proven to be an effective tool for the pre-harvest reduction of carrier rates for multiple Salmonella spp. Serum antibody assays are available to monitor exposure to wild-type Salmonella infection. This clinical study assessed protection induced by an attenuated oral Salmonella Choleraesuis vaccine against challenge infection with S. Typhimurium in swine. A serologic antibody assay was concurrently evaluated for its ability to differentiate vaccinated pigs from those challenged with Salmonella Typhimurium. Vaccination significantly improved clinical scores, pyrexia, and enteric lesion prevalence, while numerically improving average daily weight gain, and group body weight variation in comparison to unvaccinated/challenged pigs. Vaccination, while protecting pigs against disease, did not generate detectable serum antibodies prior to challenge. No vaccinated animals became seropositive prior to challenge, indicating that conventional ELISA tests could be used in vaccinated pigs to monitor wild-type exposure. Following challenge, there was no detectable difference between vaccinated/challenged and non-vaccinated/challenged animals. All strict control pigs remained serum antibody negative. These findings support the use of this vaccine to protect swine against S. Typhimurium, without confounding pre-harvest Salmonella serologic monitoring programs

    Enrichment or maceration influence post harvest isolation of Salmonella from mesenteric lymph nodes

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    Two enhanced microbiological methods were evaluated for recovery of Salmonella species from samples collected at slaughter, with a focus on ileocecal lymph nodes. Samples from one hundred and sixty two animals (vaccinated = 79, non-vaccinated = 83) were collected along with 25 pooled environmental samples (pen, truck, lairage). Animal sample types included ileocecal lymph nodes, peritoneal sponges and shoulder sponges. Initially, swabs from all samples were used to directly inoculate hektoen enteric (HE) plates

    Post harvest reduction of Salmonella by use of vaccination in growing pigs

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    This study was a randomized, blinded trial to evaluate effect of vaccine on post harvest Salmonella contamination rate of pig carcasses. Pig was the experimental unit. Litters were assigned to treatment by farrowing date and parity. Piglets were double tagged, sex recorded and entire litters were either vaccinated (oral drench) or left as non-vaccinated controls. No movement of piglets between treatments was allowed. At weaning, control litters were placed on the top level of a truck, vaccinated pigs on the bottom level, transported to a wean-finish barn, and mixed within pen at the wean-finish barn

    Two new approaches to improve the analysis of BALB/c 3T3 cell transformation assay data

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    Validation activities of the BALB/c 3T3 cell transformation assay (CTA) – a test method used for the assessment of the carcinogenic potential of compounds – have revealed the need for statistical analysis tailored to specific features of BALB/c 3T3 CTA data. Whereas a standard statistical approach for the Syrian hamster embryo (SHE) CTA was considered sufficient, an international expert group was gathered by the European Centre for the Validation of Alternative Methods (ECVAM) to review commonly applied statistical approaches for BALB/c 3T3 CTA. As it was concluded that none of the commonly applied approaches is entirely appropriate, two novel statistical approaches were found to be recommended for the evaluation of BALB/c 3T3 CTA data accounting for possible non-monotone concentration–response relationship and variance heterogeneity: a negative binomial generalised linear model with William's-type downturn-protected trend tests and a normalisation of the data by a specific transformation allowing for application of a general linear model that estimates effects assuming a normal distribution with William's-type protected tests. Both approaches are described in this article and their performance and the quality of the results they generate is demonstrated using exemplary data. Our work confirmed that both approaches are suitable for the statistical analysis of BALB/c 3T3 CTA data and that each of them is superior to commonly used methods. Furthermore, a procedure dichotomising data into negatives and positives is proposed which allows re-testing in cases where inconclusive data are encountered. The scripts of the statistical evaluation programs written in R – a freely available statistical software – are appended including exemplary outputs

    Surfactant behavior of sodium dodecylsulfate in deep eutectic solvent choline chloride/urea

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    Deep eutectic solvents (DES) resemble ionic liquids but are formed from an ionic mixture instead of being a single ionic compound. Here we present some results that demonstrate that surfactant sodium dodecyl sulfate (SDS) remains surface-active and shows self-assembly phenomena in the most commonly studied DES, choline chloride/urea. X-ray reflectivity (XRR) and small angle neutron scattering (SANS) suggest that the behavior is significantly different from that in water. Our SANS data supports our determination of the critical micelle concentration using surface-tension measurements and suggests that the micelles formed in DES do not have the same shape and size as those seen in water. Reflectivity measurements have also demonstrated that the surfactants remain surface-active below this concentration

    Clinical implications of thymidylate synthetase, dihydropyrimidine dehydrogenase and orotate phosphoribosyl transferase activity levels in colorectal carcinoma following radical resection and administration of adjuvant 5-FU chemotherapy

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    <p>Abstract</p> <p>Bckground</p> <p>A number of studies have investigated whether the activity levels of enzymes involved in 5-fluorouracil (5-FU) metabolism are prognostic factors for survival in patients with colorectal carcinoma. Most reports have examined thymidylate synthetase (TS) and dihydropyrimidine dehydrogenase (DPD) in unresectable or metastatic cases, therefore it is unclear whether the activity of these enzymes is of prognostic value in colorectal cancer patients treated with radical resection and adjuvant chemotherapy with 5-FU.</p> <p>Methods</p> <p>This study examined fresh frozen specimens of colorectal carcinoma from 40 patients who had undergone curative operation and were orally administered adjuvant tegafur/uracil (UFT) chemotherapy. TS, DPD and orotate phosphoribosyl transferase (OPRT) activities were assayed in cancer tissue and adjacent normal tissue and their association with clinicopathological variables was investigated. In addition, the relationships between TS, DPD and OPRT activities and patient survival were examined to determine whether any of these enzymes could be useful prognostic factors.</p> <p>Results</p> <p>While there was no clear relationship between pathological findings and TS or DPD activity, OPRT activity was significantly lower in tumors with lymph node metastasis than in tumors lacking lymph node metastasis. Postoperative survival was significantly better in the groups with low TS activity and/or high OPRT activity.</p> <p>Conclusion</p> <p>TS and OPRT activity levels in tumor tissue may be important prognostic factors for survival in Dukes' B and C colorectal carcinoma with radical resection and adjuvant chemotherapy with UFT.</p

    Two-vibron bound states in alpha-helix proteins : the interplay between the intramolecular anharmonicity and the strong vibron-phonon coupling

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    The influence of the intramolecular anharmonicity and the strong vibron-phonon coupling on the two-vibron dynamics in an α\alpha-helix protein is studied within a modified Davydov model. The intramolecular anharmonicity of each amide-I vibration is considered and the vibron dynamics is described according to the small polaron approach. A unitary transformation is performed to remove the intramolecular anharmonicity and a modified Lang-Firsov transformation is applied to renormalize the vibron-phonon interaction. Then, a mean field procedure is realized to obtain the dressed anharmonic vibron Hamiltonian. It is shown that the anharmonicity modifies the vibron-phonon interaction which results in an enhancement of the dressing effect. In addition, both the anharmonicity and the dressing favor the occurrence of two different bound states which the properties strongly depend on the interplay between the anharmonicity and the dressing. Such a dependence was summarized in a phase diagram which characterizes the number and the nature of the bound states as a function of the relevant parameters of the problem. For a significant anharmonicity, the low frequency bound states describe two vibrons trapped onto the same amide-I vibration whereas the high frequency bound states refer to the trapping of the two vibrons onto nearest neighbor amide-I vibrations.Comment: may 2003 submitted to Phys. Rev.
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