A Critical Comparison of Beef Semitendinosus Muscle Heated in an Oven and in a Water Bath

A comparison between characteristics of oven-roasted beef semitendinosus muscle and muscle heated as cylindrical cores in glass tubes in a water bath was conducted. Samples were heated to endpoint temperatures of 60 and 70°C at rates equivalent to heating at oven temperatures of 93 and 149°C. Oven-roasted samples had higher evaporative losses and lower drip losses than water bath samples. The effects of heating system and endpoint temperature on cooking losses and on nonfat dry weight were strongly influenced by heating rate. Expressible moisture index and fiber diameter measurements were not affected by endpoint temperature, heating system, or heating rate. Tenderness, as measured by both penetration and shear tests, was not affected by heating system; however, endpoint temperature resulted in differences in penetration chewiness with fast heating and in penetration hardness and shear firmness when samples were heated at the slow rate. With slow heating dominant wavelength and L-values of the samples were affected by both heating system and endpoint temperature. A sensory panel detected endpoint temperature and heating system differences in samples heated at both rates, but the panel was not able to detect any differences in the tenderness parameters. It was concluded that some characteristics of meat are affected by the heating system, and these effects must be considered when applying results from research involving water bath heating to oven roasting

Examining inter-sentential influences on predicted verb subcategorization

This study investigated the influences of prior discourse context and cumulative syntactic priming on readers' predictions for verb subcategorizations. An additional aim was to determine whether cumulative syntactic priming has the same degree of influence following coherent discourse contexts as when following series of unrelated sentences. Participants (N = 40) read sentences using a self-paced, sentence-by-sentence procedure. Half of these sentences comprised a coherent discourse context intended to increase the expectation for a sentential complement (S) completion. The other half consisted of scrambled sentences. The trials in both conditions varied according to the proportion of verbs that resolved to an S (either 6S or 2S). Following each condition, participants read temporarily ambiguous sentences that resolved to an S. Reading times across the disambiguating and postdisambiguating regions were measured. No significant main effects or interactions were found for either region. However, the lack of significant findings for these analyses may have been due to low power. In a follow-up analysis, data from each gender were analyzed separately. For the data contributed by males, there were no significant findings. For the data contributed by females, the effect of coherence was significant (by participants but not by items) across the postdisambiguating region, and there was a marginally significant interaction (p =.05) between coherence and frequency across this region suggesting that discourse-level information may differentially influence the local sentence processing of female and male participant

Development and characterisation of microelectrodes for extreme environments

Microelectrodes have been found to be a valuable tool in a variety of analytical studies. Their advantages over macro-sized electrodes are well known, including their enhanced mass transport properties (due to their ubiquitous hemispherical diffusion) which lead to steady state responses without external convection. They also exhibit high signal-to-noise ratios (greater sensitivities), furthering their analytical application. Microelectrode arrays are analytical devices with multiple electrodes. There are suitable for practical sensing with all the benefits of microelectrodes but with greater currents, leading to greater ease of measurement. To produce a reliable electroanalytical device the microelectrode response must be reproducible, a fundamental property based on the quality control of their production. Square microelectrode and array fabrication techniques have been developed for this purpose. This research discusses the fabrication and development of closely spaced arrays of square microelectrodes. Simulated and measured responses are compared and used to characterize electrode and array responses by cyclic voltammetry, electrical impedance spectroscopy and current-time transients. Measurements on variably spaced arrays allow insight into overlap of hemispherical diffusion from individual electrodes and the subsequent effect including peak current output on the array device. By studying these devices key insights into the mass transport properties of single square microelectrodes and microelectrode arrays were gained. This study also prepares and develops microelectrodes from materials appropriate for use in the extreme environments of molten salts and concentrated nitric acid solutions. These robust electrodes were developed for use in hydro- and pyro-chemical techniques for nuclear fuel reprocessing. These results demonstrate the practical uses for microelectrode systems across a wide range of chemical systems and in extreme conditions

Taxonomic of Pantoea associated with bacterial blight of Eucalyptus

The genus Pantoea has seven species and two sub-species, isolated from diverse geographical and ecological sources. The majority of Pantoea species are plant-associated and cause a wide variety of diseases on a range of hosts. P. ananatis causes disease on many agricultural crops including onion, maize, sudangrass, honeydew melon and pineapple. P. ananatis has been identified as the causal agent of a serious bacterial blight and dieback of Eucalyptus in South Africa. Bacterial isolates have also been recovered from Eucalypts in South America and Uganda exhibiting Pantoea ananatis-like symptoms. These isolates have not been identified. Identification of P. ananatis, based on phenotypic analysis, is difficult due to similarities in phenotypic characteristics between Pantoea species and related Enterobacteriaceae. Regular isolations of P. ananatis have highlighted the need for a rapid, molecular-based identification technique for the pathogen. A PCR assay, based on amplification of a partial region of the 16S-23S ITS gene with species-specific primers, was evaluated for the rapid identification of P. ananatis. Authentic strains of P. ananatis were included in the study, along with the unidentified isolates from South America and Uganda, and authentic strains of all species of the genus Pantoea. All authentic strains of P. ananatis produced a single PCR product of 398 bp following amplification. Only one unidentified isolate from South America produced the 398 bp PCR product. The only other species to be detected by the primers was P. stewartii subsp. indologenes. For the 16S-23S ITS-PCR assay to successfully detect only P. ananatis, the species-specific primers will have to be modified to increase their specificity. Little is known concerning the genetic relatedness between species and strains of Pantoea, and no standardised molecular typing system exists for the genus. The entire 16S-23S ITS gene was evaluated for a genetic relatedness study for the genus Pantoea. Universal primers were used to amplify the entire spacer region. Multiple amplification products were visible for all Pantoea strains and the unidentified isolates. This indicated that the Pantoea genome contains multiple copies of the rRNA operon and a high degree of similarity exists among the rRNA operons of species of the genus Pantoea. Therefore it is not possible to determine the genetic relatedness of Pantoea species based on a typing technique targeting the 16S-23S ITS region. The entire genome was then screened by AFLP analysis to examine the genetic relatedness of the genus Pantoea. The AFLP technique was found to be successful and distinct clusters were visible for each Pantoea species in the dendrogram. The majority of the South American and Ugandan isolates formed three separate clusters from P. ananatis. Representative strains were chosen from among the unidentified isolates for 16S rRNA sequencing. Based on the resulting phylogram, it is clear that at least two new Pantoea species or subspecies exist among the South American and Ugandan isolates, and more than one Pantoea species may be associated with bacterial blight and dieback of Eucalyptus. DNA-DNA hybridisations will be performed on these isolates to determine their correct taxonomic position within the genus Pantoea.Dissertation (MSc (Microbiology))--University of Pretoria, 2007.Microbiology and Plant Pathologyunrestricte

Conversion Therapy: An evidence assessment and qualitative study

A rapid evidence assessment and qualitative study that aims to improve understanding of the practice, experience and effect of conversion therapy

Article Navigation Wild-type Measles Virus Infection Upregulates Poliovirus Receptor-Related 4 and Causes Apoptosis in Brain Endothelial Cells by Induction of Tumor Necrosis Factor-Related Apoptosis-lnducing Ligand

Small numbers of brain endothelial cells (BECs) are infected in children with neurologic complications of measles virus (MV) infection. This may provide a mechanism for virus entry into the central nervous system, but the mechanisms are unclear. Both in vitro culture systems and animal models are required to elucidate events in the endothelium. We compared the ability of wild-type (WT), vaccine, and rodent-adapted MV strains to infect, replicate, and induce apoptosis in human and murine brain endothelial cells (HBECs and MBECs, respectively). Mice also were infected intracerebrally. All MV stains productively infected HBECs and induced the MV receptor PVRL4. Efficient WT MV production also occurred in MBECs. Extensive monolayer destruction associated with activated caspase 3 staining was observed in HBECs and MBECs, most markedly with WT MV. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), but not Fas ligand, was induced by MV infection. Treatment of MBECs with supernatants from MV-infected MBEC cultures with an anti-TRAIL antibody blocked caspase 3 expression and monolayer destruction. TRAIL was also expressed in the endothelium and other cell types in infected murine brains. This is the first demonstration that infection of low numbers of BECs with WT MV allows efficient virus production, induction of TRAIL, and subsequent widespread apoptosis

Understanding vulnerabilities and risk in the development of market based approaches

Progress towards resilient and sustainable development is continuous and constantly shifting as circumstances, contextual experiences and systems change. In many countries there are humanitarian and development activities taking place at the same time, yet our approaches within these areas can still be quite separated in terms of planning, implementation and monitoring. Yet traditionally quite different populations benefit from humanitarian and development interventions. Interest in the role of markets in both humanitarian and development contexts continues to grow based on the understanding that markets need to work for marginalised and vulnerable populations. Vulnerability will have an impact on the way that people can interact with market systems and trying to understand markets in relation to both personal vulnerabilities and vulnerable and fragile contexts requires a new approach, linking humanitarian and development actions more systematically

Adenoviral-mediated gene transfer of ICP47 inhibits major histocompatibility complex class I expression on vascular cells in vitro

AbstractPurpose: Many viruses have evolved mechanisms to evade detection by the host immune system. The herpes simplex gene ICP47 encodes a protein that binds to the host antigen-processing transporter, inhibiting the formation of major histocompatibility complex class I (MHC-I) antigens in infected cells. MHC-I antigen expression is also important in acute allograft rejection. This study was designed to quantitate the effect of adenoviral-mediated gene transfer of ICP47 on MHC-I cell surface expression of human vascular cells. We hypothesized that the transduction of vascular cells with a replication-incompetent adenoviral vector that was expressing ICP47 (AdICP47) would inhibit constitutive and inducible MHC-I expression and thereby reduce the rate of cytolysis of ICP47-transduced vascular cells by sensitized cytotoxic T lymphocytes (CTL). Methods: A replication-incompetent adenoviral vector, AdICP47, was created to express ICP47 driven by the cytomegalovirus immediate early promoter. Cultured human vascular endothelial and smooth muscle cells and human dermal fibroblasts were transduced with either AdICP47 or the control empty vector AddlE1. Cell surface constitutive and γ-interferon–induced MHC-I expression were quantitated by flow cytometry. A standard 4-hour chromium release cytotoxicity assay was used to determine the percent cytolysis of transduced and nontransduced endothelial cells by sensitized CTL. Finally, to quantitate the specificity of the effect of ICP47 on MHC-I expression, adhesion molecule expression was quantitated in both transduced and nontransduced cells. Results: Constitutive MHC-I expression in AdICP47-transduced endothelial cells was inhibited by a mean of 84% ± 5% (SEM) in five experiments. After 48 hours of exposure to γ-interferon, AdICP47-transduced cells exhibited a mean of 66% ± 8% lower MHC-I expression than nontransduced cells. Similar inhibition in MHC-I expression was achieved in AdICP47-transduced vascular smooth muscle cells and dermal fibroblasts. Percent cytolysis of AdICP47-transduced endothelial cells by CTL was reduced by 72%. Finally, the specificity of the effect of transduction of ICP47 on vascular cell MHC-I expression was confirmed by a lack of significant change in either constitutive or tumor necrosis factor–induced vascular cell adhesion molecule/intercellular adhesion molecule expression. Conclusion: Transduction of vascular cells with AdICP47 strongly inhibits both constitutive and inducible MHC-I expression in human vascular cells. AdICP47-transduced cells exhibited a substantial reduction in cytolysis by CTL. Thus AdICP47 transduction holds promise as a technique to characterize the role of MHC-I expression in acute vascular allograft rejection in vivo and as a potential therapeutic intervention. (J Vasc Surg 2000;31:558-66.