242 research outputs found

    Boundary Pressure Fluctuations Due to Macroturbulence in Hydraulic Jumps

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    Data concerning the statistical properties of pressure fluctuations on the containment structure associated with the hydraulic jump have been studied at the St. Anthony Falls Hydraulic Laboratory. The incident Froude numbers were investigated through the practical range from 4 to 9. The mean square of the fluctuating pressure, the mean pressure, and the power spectrum were determined as a function of position under the jump. In addition, mean and rms turbulent velocity profiles and entrained air concentration profiles throughout the jump volume were determined. The principal tests were performed in a channel 20 inches wide and 3 feet deep. Other tests at a larger scale were performed in a flume 9 feet wide and 6 feet deep to assist in an evaluation of the scaling properties of the various statistical parameters. The data indicate that the rapid rate of energy dissipation near the toe of the jump leads to a maximum rms fluctuation pressure on the bed of about 5 per cent of the incoming velocity head. The location of the maximum pressure fluctuation is approximately midway under the roller of the jump

    What Do We Know? Review of U.S. Public Genetic Modification Literacy Reveals Little Empirical Data

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    As genetic modification for food production has expanded, U.S. public discourse about the acceptance and regulation of use of these products has also expanded. Dissent is currently presumed to be widespread. However, assessments of public agricultural literacy around the technology alternatives are limited, especially in the context of food production versus medical genetic testing, about potential environmental risk and other reasons for dissent. Assessments also tend to focus on consumer knowledge in outdated deficit-model frameworks. In preparation for an assessment of U.S. adult public understanding of traditional breeding and genetic engineering technology, we reviewed existing agricultural literacy and science literacy literature to determine current understanding and locate existing instruments on which to build such an assessment. Of 323 peer-reviewed articles, we found only four that empirically examined U.S. adult public audiences in the context of literacy related to genetic modification for food. Results from agricultural economics and four gray literature pieces provided additional context and direction for our own survey development. We suggest ways to build a more representative and meaningful survey relying on more than knowledge deficits to characterize agricultural literacy and plant genetic literacy. This will lay the foundation for understanding why dissent over such agricultural topics exists

    Precedings of Arkansas Lakes Symposium Limnological Studies of Lake Chicot, Arkansas

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    Lake Chicot is an oxbow lake that was created more than 600 years ago by the meandering of the Mississippi River. It is located in Chicot county in southeastern Arkansas adjacent to the present Mississippi River. As the largest natural lake in Arkansas it earned an early reputation for its good fishing and recreational value. Development of a levee system forced the enlargement of the lakes watershed to its present 350 square miles. Initially this alteration affected only the volume flow through the lake, drastically reducing the water residence time. Because the watershed was located in one of the most agriculturally productive regions in the world, the land, predominantly comprised of clay and fine silts, quickly became more intensively farmed. The use of agricultural chemicals increased, large amounts of sediments were produced and the lake began to become severely impacted by this activity

    Non-host volatile blend optimization for forest protection against the European Spruce Bark Beetle, Ips typographus

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    Conifer feeding bark beetles (Coleoptera, Curculionidae, Scolytinae) pose a serious economic threat to forest production. Volatiles released by non-host angiosperm plants (so called non-host volatiles, NHV) have been shown to reduce the risk of attack by many bark beetle species, including the European spruce bark beetle, Ips typographus. However, the most active blend for I. typographus, containing three green leaf volatiles (GLVs) in addition to the key compounds trans-conophthorin (tC) and verbenone, has been considered too expensive for use in large-scale management. To lower the cost and improve the applicability of NHV, we aim to simplify the blend without compromising its anti-attractant potency. Since the key compound tC is expensive in pure form, we also tested a crude version: technical grade trans-conophthorin (T-tC). In another attempt to find a more cost effective substitute for tC, we evaluated a more readily synthesized analog: dehydroconophthorin (DHC). Our results showed that 1-hexanol alone could replace the three-component GLV blend containing 1- hexanol, (3Z)-hexen-1-ol, and (2E)-hexen-1-ol. Furthermore, the release rate of tC could be reduced from 5 mg/day to 0.5 mg/day in a blend with 1-hexanol and (–)-verbenone without compromising the anti-attractant activity. We further show that T-tC was comparable with tC, whereas DHC was a less effective anti-attractant. DHC also elicited weaker physiological responses in the tC-responding olfactory receptor neuron class, providing a likely mechanistic explanation for its weaker anti-attractive effect. Our results suggest a blend consisting of (–)-verbenone, 1-hexanol and technical transconophthorin as a cost-efficient anti-attractant for forest protection against I. typographus

    The phosphatidylserine receptor has essential functions during embryogenesis but not in apoptotic cell removal

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    BACKGROUND: Phagocytosis of apoptotic cells is fundamental to animal development, immune function and cellular homeostasis. The phosphatidylserine receptor (Ptdsr) on phagocytes has been implicated in the recognition and engulfment of apoptotic cells and in anti-inflammatory signaling. To determine the biological function of the phosphatidylserine receptor in vivo, we inactivated the Ptdsr gene in the mouse. RESULTS: Ablation of Ptdsr function in mice causes perinatal lethality, growth retardation and a delay in terminal differentiation of the kidney, intestine, liver and lungs during embryogenesis. Moreover, eye development can be severely disturbed, ranging from defects in retinal differentiation to complete unilateral or bilateral absence of eyes. Ptdsr (-/-) mice with anophthalmia develop novel lesions, with induction of ectopic retinal-pigmented epithelium in nasal cavities. A comprehensive investigation of apoptotic cell clearance in vivo and in vitro demonstrated that engulfment of apoptotic cells was normal in Ptdsr knockout mice, but Ptdsr-deficient macrophages were impaired in pro- and anti-inflammatory cytokine signaling after stimulation with apoptotic cells or with lipopolysaccharide. CONCLUSION: Ptdsr is essential for the development and differentiation of multiple organs during embryogenesis but not for apoptotic cell removal. Ptdsr may thus have a novel, unexpected developmental function as an important differentiation-promoting gene. Moreover, Ptdsr is not required for apoptotic cell clearance by macrophages but seems to be necessary for the regulation of macrophage cytokine responses. These results clearly contradict the current view that the phosphatidylserine receptor primarily functions in apoptotic cell clearance

    Decreased expression of haemoglobin beta (HBB) gene in anaplastic thyroid cancer and recovory of its expression inhibits cell growth

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    Anaplastic thyroid cancer (ATC) is one of the most fulminant and foetal diseases in human malignancies. However, the genetic alterations and carcinogenic mechanisms of ATC are still unclear. Recently, we investigated the gene expression profile of 11 anaplastic thyroid cancer cell lines (ACL) and significant decreased expression of haemoglobin beta (HBB) gene in ACL. Haemoglobin beta is located at 11p15.5, where loss of heterozygosity (LOH) was reported in various kinds of cancers, including ATC, and it has been suggested that novel tumour suppressor genes might exist in this region. In order to clarify the meaning of decreased expression of HBB in ATC, the expression status of HBB was investigated with ACL, ATC, papillary thyroid cancer (PTC) and normal human tissues. Haemoglobin beta showed significant decreased expression in ACLs and ATCs; however, in PTC, HBB expressed equal to the normal thyroid gland. In addition, HBB expressed in normal human tissues ubiquitously. To validate the tumour-suppressor function of HBB, cell growth assay was performed. Forced expression of HBB in KTA2 cell, which is a kind of ACL, significantly suppressed KTA2 growth. The mechanism of downregulation of HBB in ATC is still unclear; however, our results suggested the possibility of HBB as a novel tumour-suppressor gene

    Loss of heterozygosity of TRIM3 in malignant gliomas

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    <p>Abstract</p> <p>Background</p> <p>Malignant gliomas are frequent primary brain tumors associated with poor prognosis and very limited response to conventional chemo- and radio-therapies. Besides sharing common growth features with other types of solid tumors, gliomas are highly invasive into adjacent brain tissue, which renders them particularly aggressive and their surgical resection inefficient. Therefore, insights into glioma formation are of fundamental interest in order to provide novel molecular targets for diagnostic purposes and potential anti-cancer drugs. Human <it>Tripartite motif protein 3 </it>(<it>TRIM3</it>) encodes a structural homolog of <it>Drosophila brain tumor </it>(<it>brat</it>) implicated in progenitor cell proliferation control and cancer stem cell suppression. <it>TRIM3 </it>is located within the loss of allelic heterozygosity (LOH) hotspot of chromosome segment 11p15.5, indicating a potential role in tumor suppression. ...</p> <p>Methods</p> <p>Here we analyze 70 primary human gliomas of all types and grades and report somatic deletion mapping as well as single nucleotide polymorphism analysis together with quantitative real-time PCR of chromosome segment 11p15.5.</p> <p>Results</p> <p>Our analysis identifies LOH in 17 cases (24%) of primary human glioma which defines a common 130 kb-wide interval within the <it>TRIM3 </it>locus as a minimal area of loss. We further detect altered genomic dosage of <it>TRIM3 </it>in two glioma cases with LOH at 11p15.5, indicating homozygous deletions of <it>TRIM3</it>.</p> <p>Conclusion</p> <p>Loss of heterozygosity of chromosome segment 11p15.5 in malignant gliomas suggests <it>TRIM3 </it>as a candidate brain tumor suppressor gene.</p
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