554 research outputs found
Fish Distribution in the Skunk River below Ames, Iowa
The Skunk River has been straightened most of the way from Ames to Colfax. In the summer of 1968, 24 species of fish were collected. There were few species other than minnows, and red shiner (Notropis lutrensis), bigmouth shiner (N. dorsalis) and sand shiner (N. straminous) were most abundant. Water levels were above normal during the study and effects of pollution upon fish distribution were not pronounced. The diversity index, d, at the station where treated-sewage wastes entered, was lower than at stations up and down stream but was higher than at the four stations farthest downstream. Uniformity of habitat resulting from stream-straightening probably limits species diversity
Transport coefficients for electrolytes in arbitrarily shaped nano and micro-fluidic channels
We consider laminar flow of incompressible electrolytes in long, straight
channels driven by pressure and electro-osmosis. We use a Hilbert space
eigenfunction expansion to address the general problem of an arbitrary cross
section and obtain general results in linear-response theory for the hydraulic
and electrical transport coefficients which satisfy Onsager relations. In the
limit of non-overlapping Debye layers the transport coefficients are simply
expressed in terms of parameters of the electrolyte as well as the geometrical
correction factor for the Hagen-Poiseuille part of the problem. In particular,
we consider the limits of thin non-overlapping as well as strongly overlapping
Debye layers, respectively, and calculate the corrections to the hydraulic
resistance due to electro-hydrodynamic interactions.Comment: 13 pages including 4 figures and 1 table. Typos corrected. Accepted
for NJ
Ericsson INC., AND Telefonaktiebolaget LM Ericsson v. Samsung Elecs. CO, LTD., Samsung Elecs. America
Unopposed Motion for Leave to File Brief of International Intellectual Property Law Professors as Amici Curiae in Support of Neither Part
Evaluating of HPV-DNA ISH as an adjunct to p16 testing in oropharyngeal cancer
© 2020 Jeffrey Chi. Aim: Current guidelines recommend p16 immunohistochemistry (IHC) for testing human papillomavirus (HPV) in oropharyngeal carcinoma (OPSCC). We evaluated the value of adding DNA in situ hybridization (ISH) to p16 IHC. Methods: Fifty patients with OPSCC were analyzed. Concordance between HPV-DNA ISH and p16 IHC was measured by Gwet\u27s agreement coefficient. Results: p16 IHC was positive in 35/48 (72.9%), negative in 8/48 (16.7%) patients. Wide spectrum DNA-ISH was positive in 9/23 (39%) and negative in 14/23 (60.9%) patients. High-risk 16/18 (HR) HPV DNA-ISH was positive in 11/23 (47.8%) and negative in 12 (52.2%) patients. The agreement between HPV DNA-ISH and p16 IHC is fair (Gwet\u27s AC1 = 0.318). Conclusion: The agreement between p16 IHC and HPV-DNA ISH was fair. However, ISH sensitivity was low. Our findings add to the current data that p16 IHC testing is reliable and may be enough as a stand-alone test for HPV detection in OPSCC. Current testing guidelines recommend p16 immunochemistry (IHC) for detecting human papillomavirus (HPV) in oropharyngeal cancer (OPSCC). We evaluated the value of adding HPV DNA in situ hybridization (ISH) to p16 IHC. Fifty patients with OPSCC were analyzed. p16 IHC was positive in 72.9% of patients and DNA-ISH was positive in 39% of patients when wide spectrum probe was used and positive in 47.8% of patients when high-risk probe was used. The agreement between the two tests was fair. However, DNA-ISH sensitivity was low. p16 IHC may be enough as a stand-alone test for detection of HPV in OPSCC
Targeted microbubbles: a novel application for the treatment of kidney stones
Kidney stone disease is endemic. Extracorporeal shockwave lithotripsy was the first major technological breakthrough where focused shockwaves were used to fragment stones in the kidney or ureter. The shockwaves induced the formation of cavitation bubbles, whose collapse released energy at the stone, and the energy fragmented the kidney stones into pieces small enough to be passed spontaneously. Can the concept of microbubbles be used without the bulky machine? The logical progression was to manufacture these powerful microbubbles ex vivo and inject these bubbles directly into the collecting system. An external source can be used to induce cavitation once the microbubbles are at their target; the key is targeting these microbubbles to specifically bind to kidney stones. Two important observations have been established: (i) bisphosphonates attach to hydroxyapatite crystals with high affinity; and (ii) there is substantial hydroxyapatite in most kidney stones. The microbubbles can be equipped with bisphosphonate tags to specifically target kidney stones. These bubbles will preferentially bind to the stone and not surrounding tissue, reducing collateral damage. Ultrasound or another suitable form of energy is then applied causing the microbubbles to induce cavitation and fragment the stones. This can be used as an adjunct to ureteroscopy or percutaneous lithotripsy to aid in fragmentation. Randall's plaques, which also contain hydroxyapatite crystals, can also be targeted to pre-emptively destroy these stone precursors. Additionally, targeted microbubbles can aid in kidney stone diagnostics by virtue of being used as an adjunct to traditional imaging methods, especially useful in high-risk patient populations. This novel application of targeted microbubble technology not only represents the next frontier in minimally invasive stone surgery, but a platform technology for other areas of medicine
Ectopic expression of the beta-cell specific transcription factor Pdx1 inhibits glucagon gene transcription
Aims/hypothesis: The transcription factor Pdx1 is required for the development and differentiation of all pancreatic cells. Beta-cell specific inactivation of Pdx1 in developing or adult mice leads to an increase in glucagon-expressing cells, suggesting that absence of Pdx1could favour glucagon gene expression by a default mechanism. Method: We investigated the inhibitory role of Pdx1 on glucagon gene expression in vitro. The glucagonoma cell line InR1G9 was transduced with a Pdx1-encoding lentiviral vector and insulin and glucagon mRNA levels were analysed by northern blot and real-time PCR. To understand the mechanism by which Pdx1 inhibits glucagon gene expression, we studied its effect on glucagon promoter activity in non-islet cells using transient transfections and gel-shift analysis. Results: In glucagonoma cells transduced with a Pdx1-encoding lentiviral vector, insulin gene expression was induced while glucagon mRNA levels were reduced by 50 to 60%. In the heterologous cell line BHK-21, Pdx1 inhibited by 60 to 80% the activation of the α-cell specific element G1 conferred by Pax-6 and/or Cdx-2/3. Although Pdx1 could bind three AT-rich motifs within G1, two of which are binding sites for Pax-6 and Cdx-2/3, the affinity of Pdx1 for G1 was much lower as compared to Pax-6. In addition, Pdx1 inhibited Pax-6 mediated activation through G3, to which Pdx1 was unable to bind. Moreover, a mutation impairing DNA binding of Pdx1 had no effect on its inhibition on Cdx-2/3. Since Pdx1 interacts directly with Pax-6 and Cdx-2/3 forming heterodimers, we suggest that Pdx1 inhibits glucagon gene transcription through protein to protein interactions with Pax-6 and Cdx-2/3. Conclusion/interpretation: Cell-specific expression of the glucagon gene can only occur when Pdx1 expression extinguishes from the early α cell precurso
Laser enhanced high-intensity focused ultrasound thrombolysis: An in vitro study
This is the Published Version made available with the permission of the publisher. Copyright, Ecological Society of America.Laser-enhanced thrombolysis by high intensity focused ultrasound (HIFU) treatment was studied in vitro with bovine blood
clots. To achieve laser-enhanced thrombolysis, laser light was employed to illuminate the sample concurrently with HIFU radiation, and ultrasound and laser parameters were optimized to achieve better thrombolysis efficiency. The results indicated that the thrombolysis efficiency increased when pulse length of HIFU wave, HIFU pressure, or laser fluence increases. Also, with the presence of laser, an enhanced effect of thrombolysis was observed.This study was supported in part byNIH Grant No. 1R03EB015077-01A1
Development of control mechanisms for a laser wakefield accelerator-driven bremsstrahlung x-ray source for advanced radiographic imaging
A high power laser was used to accelerate electrons in a laser-driven wakefield accelerator. The high energy electrons were then used to generate an x-ray beam by passing them through a converter target. This bremsstrahlung source was characterised and used to perform penetrative imaging of industrially relevant samples. The photon spectrum had a critical energy in excess of 100 MeV and a source size smaller than the resolution of the diagnostic (≲150 µm). Simulations indicate a significantly smaller source is achievable. Variations in the x-ray source characteristics were realised through changes to the plasma and converter parameters while simulations confirm the adaptability of the source. Imaging of high areal density objects with 150 µm resolution was performed, demonstrating the unique advantages of this novel source
Bioenergy and African transformation
FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOAmong the world's continents, Africa has the highest incidence of food insecurity and poverty and the highest rates of population growth. Yet Africa also has the most arable land, the lowest crop yields, and by far the most plentiful land resources relative to energy demand. It is thus of interest to examine the potential of expanded modern bioenergy production in Africa. Here we consider bioenergy as an enabler for development, and provide an overview of modern bioenergy technologies with a comment on application in an Africa context. Experience with bioenergy in Africa offers evidence of social benefits and also some important lessons. In Brazil, social development, agricultural development and food security, and bioenergy development have been synergistic rather than antagonistic. Realizing similar success in African countries will require clear vision, good governance, and adaptation of technologies, knowledge, and business models to myriad local circumstances. Strategies for integrated production of food crops, livestock, and bioenergy are potentially attractive and offer an alternative to an agricultural model featuring specialized land use. If done thoughtfully, there is considerable evidence that food security and economic development in Africa can be addressed more effectively with modern bioenergy than without it. Modern bioenergy can be an agent of African transformation, with potential social benefits accruing to multiple sectors and extending well beyond energy supply per se. Potential negative impacts also cut across sectors. Thus, institutionally inclusive multi-sector legislative structures will be more effective at maximizing the social benefits of bioenergy compared to institutionally exclusive, single-sector structures.Among the world's continents, Africa has the highest incidence of food insecurity and poverty and the highest rates of population growth. Yet Africa also has the most arable land, the lowest crop yields, and by far the most plentiful land resources relative to energy demand. It is thus of interest to examine the potential of expanded modern bioenergy production in Africa. Here we consider bioenergy as an enabler for development, and provide an overview of modern bioenergy technologies with a comment on application in an Africa context. Experience with bioenergy in Africa offers evidence of social benefits and also some important lessons. In Brazil, social development, agricultural development and food security, and bioenergy development have been synergistic rather than antagonistic. Realizing similar success in African countries will require clear vision, good governance, and adaptation of technologies, knowledge, and business models to myriad local circumstances. Strategies for integrated production of food crops, livestock, and bioenergy are potentially attractive and offer an alternative to an agricultural model featuring specialized land use. If done thoughtfully, there is considerable evidence that food security and economic development in Africa can be addressed more effectively with modern bioenergy than without it. Modern bioenergy can be an agent of African transformation, with potential social benefits accruing to multiple sectors and extending well beyond energy supply per se. Potential negative impacts also cut across sectors. Thus, institutionally inclusive multi-sector legislative structures will be more effective at maximizing the social benefits of bioenergy compared to institutionally exclusive, single-sector structures.8118FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP [2012/00282-3]2012/00282-3Partial support was provided by grant 2012/00282-3 from the Sao Paulo Research Foundation, the NEPAD-FAO project under the EU-FAO Global Governance for Hunger Reduction Programme, and the Link Foundation (support for LRL)
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