263 research outputs found
Design of a Film Cooling Experiment for Rocket Engines
The Film Cooling Rig (FCR) is a new test rig at the Air Force Institute of Technology (AFIT) to study film cooling for rocket engine applications. The original researcher designed, built, and then utilized the FCR to study radial curvature effects on film cooling for a non-combustion environment. This effort modified the FCR by adding propane-air combustion. Modular stainless steel test sections were produced to allow study of various curvatures and coolant injection angles. A pre-mixed burner was designed and built to deliver main flow mass flow rates necessary to produce blowing ratios as low as 0.5. A water cooling system was designed for the entire FCR, but only implemented for the curved test sections. Instrumentation in this system allows calculation of the average heat flux to the test section. Once the necessary FCR and lab modifications were accomplished, the operating range of the FCR was developed and tested using infrared thermography. Surface temperature measurements near the cooling hole showed no cooling effect for 13 major test configurations, and many more minor variations. The lack of cooling was caused by inadequate spreading of the burner flow to the test section wall. Without the necessary main flow momentum across the test section wall, the coolant flow did not turn and adhere to the wall. Instead, it jetted into the main flow without cooling the wall as expected. Recommendations included modifications to the existing rig to correct the main flow issue, along with a completely new FCR design incorporating the lessons learned from this research to produce a simpler, more effective rig. The new design allows the laser and infrared diagnostics of the first rig without the manufacturing complications that hindered testing in the first FCR
Letter from R.L. Sincock to R.B. LeCocq, February 9, 1959
Letter from the field editor of The Washington Farmer, a state farm magazine, describing the return of various materials borrowed from Ralph, the printing of a new story about Bang\u27s Disease control, and apologies for not answering sooner.https://nwcommons.nwciowa.edu/lecocqfarm/1004/thumbnail.jp
Calcium and ageing in the Rotifer Mytilina Brevispina Var Redunca
Rotifers of the species Mytilina brevispina var redunca were cultured at 24°C under standard and aseptic culture conditions in artificial saline media of three calcium concentrations. 1. All populations were homologated with respect to maternal age by a process of egg selection carried out over three generations. 2. Observations on survival, growth and egg production were made on populations cultured on the three media containing a-full and reduced diet, while the effects of transfer between culture media, periodic washing in chelating agents, and constant exposure to antioxidants were tested on survival and egg-laying in Control cultures. 3, The calcium content of rotifers was investigated by continual exposure to the radionuclide 45 calcium in the three culture media, while the 45 calcium accumulated and withdrawn from rotifers cultured on Control 45 calcium medium and subjected to treatment with the chelating agent sodium citrate, and the 45 calcium accumulated in rotifers cultured on Control 45 calcium medium containing the antioxidant B.H.T., were also investigated. The 45 calcium intake of algae cultured for one day on Control 4-5 calcium medium at the concentration normally employed for experiments was noted. 4. In the case of rotifers cultured on a full diet in the three calcium media the greatest longevity, egg' total, and reproductive period was recorded in the Low calcium cultured population, while the lowest longevity value and total number of eggs laid was recorded in the High calcium group. Continual exposure to 4-5 calcium in each of the three media, revealed an accumulation of calcium that began in all cases at the end of the period of growth in size. This accumulation occurred at a rate that was inverse.ly related to longevity and directly related to the level of radionuclide in each medium in the manner predicted by the Lansing hypothesis. The total 45 calcium taken up in the daily intake of algae in 4 day old rotifers cultured on Control medium approximately the same order as the maximum rate of 45 calcium accumulation in untreated rotifers cultured on the same medium, suggesting a possible source of calcium accumulation in the event of a breakdown in the mechanism of excretion. 5. Rotifers cultured on a reduced diet in each of the three media showed an increase in longevity, egg total and reproductive period compared with rotifers cultured in the corresponding media on a full diet. However, the relative differences with respect to these characteristics were approximately similar between populations cultured on the same dietary level, with the Low calcium cultured population showing the greatest increase in longevity, total egg production and reproductive period. No execution in the growth period or difference in final size was noted in the case of the dietary restricted groups (cf McCay's starvation studies). 6. The results of the culture transfer experiments in which rotifers were transferred to another of the three media at the end of the growth period, revealed that it was the medium on which rotifers were cultured after growth that exerted the major influence on longevity value, total egg production and length of reproductive period. This result is in agreement with the appearance of an ageing factor at the end of the period of growth size postulated in the Lansing ageing theory
PETA-3/CD151, a member of the transmembrane 4 superfamily, is localised to the plasma membrane and endocytic system of endothelial cells, associates with multiple integrins and modulates cell function
The Transmembrane 4 Superfamily member, PETA-3/CD151, is ubiquitously expressed by endothelial cells in vivo. In cultured human umbilical vein endothelial cells PETA-3 is present on the plasma membrane and predominantly localises to regions of cell-cell contact. Additionally, this protein is abundant within an intracellular compartment which accounts for up to 66% of the total PETA-3 expressed. Intracellular PETA-3 showed colocalisation with transferrin receptor and CD63 suggesting an endosomal/lysosomal localisation which was supported by immuno-electronmicroscopy studies. Co-immunoprecipitation experiments investigating possible interactions of PETA-3 with other molecules demonstrated associations with several integrin chains including beta1, beta3, beta4, (alpha)2, (alpha)3, (alpha)5, (alpha)6 and provide the first report of Transmembrane 4 Superfamily association with the (alpha)6beta4 integrin. Using 2-colour confocal microscopy, we demonstrated similar localisation of PETA-3 and integrin chains within cytoplasmic vesicles and endothelial cell junctions. In order to assess the functional implications of PETA-3/integrin associations, the effect of anti-PETA-3 antibodies on endothelial function was examined. Anti-PETA-3 mAb inhibited endothelial cell migration and modulated in vitro angiogenesis, but had no detectable effect on neutrophil transendothelial migration. The broad range of integrin associations and the presence of PETA-3 with integrins both on the plasma membrane and within intracellular vesicles, suggests a primary role for PETA-3 in regulating integrin trafficking and/or function.Paul M. Sincock, Stephen Fitter, Robert G. Parton, Michael C. Berndt, Jennifer R. Gamble and Leonie K. Ashma
The role of porcine reproductive and respiratory syndrome (PRRS) virus structural and non-structural proteins in virus pathogenesis
Porcine reproductive and respiratory syndrome (PRRS) is an economically devastating viral
disease affecting the swine industry worldwide. The etiological agent, PRRS virus (PRRSV),
possesses a RNA viral genome with nine open reading frames (ORFs). The ORF1a and ORF1b
replicase-associated genes encode the polyproteins pp1a and pp1ab, respectively. The pp1a is
processed in nine non-structural proteins (nsps): nsp1a, nsp1b, and nsp2 to nsp8. Proteolytic
cleavage of pp1ab generates products nsp9 to nsp12. The proteolytic pp1a cleavage products
process and cleave pp1a and pp1ab into nsp products. The nsp9 to nsp12 are involved in virus
genome transcription and replication. The 30 end of the viral genome encodes four minor
and three major structural proteins. The GP2a, GP3 and GP4 (encoded by ORF2a, 3 and 4), are
glycosylated membrane associated minor structural proteins. The fourth minor structural
protein, the E protein (encoded by ORF2b), is an unglycosylated membrane associated protein.
The viral envelope contains two major structural proteins: a glycosylated major envelope
protein GP5 (encoded by ORF5) and an unglycosylated membrane M protein (encoded by
ORF6). The third major structural protein is the nucleocapsid N protein (encoded by ORF7). All
PRRSV non-structural and structural proteins are essential for virus replication, and PRRSV
infectivity is relatively intolerant to subtle changes within the structural proteins. PRRSV
virulence is multigenic and resides in both the non-structural and structural viral proteins. This
review discusses the molecular characteristics, biological and immunological functions of the
PRRSV structural and nsps and their involvement in the virus pathogenesis
Different states of integrin LFA-1 aggregation are controlled through its association with tetraspanin CD9
This is the author’s version of a work that was accepted for publication in Biochimica et Biophysica Acta - Mollecular Cell Research. A definitive version was subsequently published in Biochimica et Biophysica Acta - Mollecular Cell Research, 1853.10 (2015): 2464-2480 DOI: 10.1016/j.bbamcr.2015.05.018The tetraspanin CD9 has been shown to interact with different members of the β1 and
β3 subfamilies of integrins, regulating through these interactions cell adhesion,
migration and signaling. Based on confocal microscopy co-localization and on coimmunoprecipitation
results, we report here that CD9 associates with the β2 integrin
LFA-1 in different types of leukocytes including T, B and monocytic cells. This
association is resistant to stringent solubilisation conditions which, together with data
from chemical crosslinking, in situ Proximity Ligation Assays and pull-down
experiments, suggests a primary/direct type of interaction mediated by the Large
Extracellular Loop of the tetraspanin. CD9 exerts inhibitory effects on the adhesive
function of LFA-1 and on LFA-1-dependent leukocyte cytotoxic activity. The
mechanism responsible for this negative regulation exerted by CD9 on LFA-1 adhesion
does not involve changes in the affinity state of this integrin but seems to be related to
alterations in its state of aggregationThis work was supported by grant SAF2012-34561 from the Spanish «Ministerio de
EconomÃa y Competitividad-MINECO», (to C.C.). R.R.M. salary is supported by a
«Profesor Ayudante» position from Departamento de BiologÃa, Facutad de Ciencias,
Universidad Autónoma de Madri
Tetraspanin CD151 is a novel prognostic marker in poor outcome endometrial cancer
BACKGROUND: Type II cancers account for 10% of endometrial cancers but 50% of recurrence. Response rates to chemotherapy at recurrence are poor and better prognostic markers are needed to guide therapy. CD151 is a small transmembrane protein that regulates cell migration and facilitates cancer metastasis. High CD151 expression confers poor prognosis in breast, pancreatic and colorectal cancer. The prognostic significance of tetraspanin CD151 expression in poor outcome endometrial cancers was evaluated, along with oestrogen receptor (ER), progesterone receptor (PR), p53, human epidermal growth factor receptor -2 (HER-2), and CD 151 staining compared with α6β1, α3β1 integrins, and E-cadherin. METHODS: Tissue microarray constructed from 156 poor outcome endometrial cancers, tested with immunohistochemistry and staining correlated with clinicopathological data were used. A total of 131 data sets were complete for analysis. RESULTS: Expression of CD151 was significantly higher in uterine papillary serous and clear cell carcinoma than in grade 3 endometrioid carcinoma, sarcoma or carcinosarcoma (P<0.001). In univariate analysis, age, stage, histology type and CD151 were significant for both recurrence free (RFS) and disease specific survival (DSS). In multivariate analyses, CD151 was significant for RFS and DSS (P=0.036 and 0.033, respectively) in triple negative (ER, PR and HER-2 negative) tumours (88/131). The HER-2, p53, ER and PR were not prognostic for survival. There was strong concordance of CD151 with E-cadherin (98%), but not with α6β1 (35%), α3β1 staining (60%). CONCLUSION: The CD151 is a novel marker in type 2 cancers that can guide therapeutic decisions. CD151 may have an important role in tumourigenesis in some histology types
Biological effects of naturally occurring and man-made fibres: in vitro cytotoxicity and mutagenesis in mammalian cells
Cytotoxicity and mutagenicity of tremolite, erionite and the man-made ceramic (RCF-1) fibre were studied using the human– hamster hybrid A L cells. Results from these fibres were compared with those of UICC Rhodesian chrysotile fibres. The A L cell mutation assay, based on the S1 gene marker located on human chromosome 11, the only human chromosome contained in the hybrid cell, has been shown to be more sensitive than conventional assays in detecting deletion mutations. Tremolite, erionite and RCF-1 fibres were significantly less cytotoxic to A L cells than chrysotile. Mutagenesis studies at the HPRT locus revealed no significant mutant yield with any of these fibres. In contrast, both erionite and tremolite induced dose-dependent S1− mutations in fibre-exposed cells, with the former inducing a significantly higher mutant yield than the latter fibre type. On the other hand, RCF-1 fibres were largely non-mutagenic. At equitoxic doses (cell survival at ∼ 0.7), erionite was found to be the most potent mutagen among the three fibres tested and at a level comparable to that of chrysotile fibres. These results indicate that RCF-1 fibres are non-genotoxic under the conditions used in the studies and suggest that the high mesothelioma incidence previously observed in hamster may either be a result of selective sensitivity of hamster pleura to fibre-induced chronic irritation or as a result of prolonged fibre treatment. Furthermore, the relatively high mutagenic potential for erionite is consistent with its documented carcinogenicity. © 1999 Cancer Research Campaig
Prioritizing progressive MS rehabilitation research: A call from the International Progressive MS Alliance
Background: People with multiple sclerosis (MS) experience myriad symptoms that negatively affect their quality of life. Despite significant progress in rehabilitation strategies for people living with relapsing-remitting MS (RRMS), the development of similar strategies for people with progressive MS has received little attention. Objective: To highlight key symptoms of importance to people with progressive MS and stimulate the design and implementation of high-quality studies focused on symptom management and rehabilitation. Methods: A group of international research experts, representatives from industry, and people affected by progressive MS was convened by the International Progressive MS Alliance to devise research priorities for addressing symptoms in progressive MS. Results: Based on information from the MS community, we outline a rationale for highlighting four symptoms of particular interest: fatigue, mobility and upper extremity impairment, pain, and cognitive impairment. Factors such as depression, resilience, comorbidities, and psychosocial support are described, as they affect treatment efficacy. Conclusions: This coordinated call to action—to the research community to prioritize investigation of effective symptom management strategies, and to funders to support them—is an important step in addressing gaps in rehabilitation research for people affected by progressive MS. </jats:sec
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