1,206 research outputs found

    Ultrasonic borehole flowmeter

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    Published ArticleAlthough research has been conducted in the field of Acoustic Doppler Borehole Flowmeters (ADBF), it has been focused on point source of flow and three dimensional borehole flow techniques. However as of yet, no studies have been conducted on the possible use of Acoustic Doppler Borehole Profiling (ADBP). This technique of borehole flow measurement is possibly a revolutionary concept in how vertical flow in a borehole is measured. It makes use of a single inexpensive transducer that can float on the surface of the water in a borehole and use Acoustic Doppler techniques to profile the flow in a borehole. No complicated and expensive flow probe winching systems will be required. Another added benefit of the ADBP will be the non-evasive technologies that comprise its design. Current borehole flow probes are required to be present at the point of flow measurement in the borehole. The presence of the probe inadvertently alters the flow in the borehole by adding resistance to the flow in the borehole. Under stressed or pumped flow tests these flow resistance effects cause sufficient pressure gradients at the flow sensors to divert part of the flow away from the sensor. This causes erroneous readings of flow as a part of the flow in the borehole is not accounted for. In ADBP the sensor is not physically present at the point of flow being read. This makes the ADBP technique of borehole flow measurement far more representative of the natural flow conditions in the borehole under ambient and stressed conditions

    The Emerging Role of Telomerase Reverse Transcriptase in Mitochondrial DNA Metabolism

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    Telomerase is a reverse transcriptase specialized in telomere synthesis. The enzyme is primarily nuclear where it elongates telomeres but recent reports have shown that it also localizes to mitochondria. The function of TERT in mitochondria is largely unknown but the available findings point to a role in mitochondrial DNA metabolism. This paper discusses the available data on mitochondrial telomerase with particular emphasis on its effects upon the organellar DNA

    Differences and Similarities in Rural Residents’ Health and Cardiac Risk Factors

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    Purpose: The current U.S. population exceeds three hundred million with approximately 20% living in non-urban rural areas. A higher percentage of rural residents have diagnosed heart disease and report poorer health compared to non-rural residents; however, it is not known whether risk factor modification for heart disease and health status differ based on degree of rurality. The purposes of this study were: 1) to compare differences in health status and cardiac risk factors between cardiac patients living in large and small/isolated rural areas, and 2) to compare the health status of rural cardiac patients with a national sample. Method: A secondary analysis using data from three separate studies was completed using a comparative descriptive design. The Cardiac Rehabilitation participant sample (n-191) included individuals 3 to 12 months post-cardiac event. The Arizona Heart Institute and Foundation Heart Test measured risk factors and the eight subscales of the Short-Form, Medical Outcomes study measured health status. Findings: No significant differences in health status were found; all participants rated their health moderately high. However, individuals in large rural areas reported significantly better general health than those in the normative sample. No differences in smoking, blood pressure, diabetes, or overweight/obese BMI were found between the two rural groups. Differences in exercise, and anger were present between the two groups. Significant differences were identified in waist circumference between the genders placing women at higher risk for heart disease. Conclusions: Identifying health status and cardiovascular risk factors of rural individuals informs interventions to be tested for rural residents

    Enhancing Vibrational Light-Matter Coupling Strength beyond the Molecular Concentration Limit Using Plasmonic Arrays

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    Vibrational strong coupling is emerging as a promising tool to modify molecular properties by making use of hybrid light-matter states known as polaritons. Fabry-Perot cavities filled with organic molecules are typically used, and the molecular concentration limits the maximum reachable coupling strength. Developing methods to increase the coupling strength beyond the molecular concentration limit are highly desirable. In this Letter, we investigate the effect of adding a gold nanorod array into a cavity containing pure organic molecules using FT-IR microscopy and numerical modeling. Incorporation of the plasmonic nanorod array that acts as artificial molecules leads to an order of magnitude increase in the total coupling strength for the cavity with matching resonant frequency filled with organic molecules. Additionally, we observe a significant narrowing of the plasmon line width inside the cavity. We anticipate that these results will be a step forward in exploring vibropolaritonic chemistry and may be used in plasmon based biosensors

    Manifesting Unobtainable Secrets: Threshold Elliptic Curve Key Generation using Nested Shamir Secret Sharing

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    We present a mechanism to manifest unobtainable secrets using a nested Shamir secret sharing scheme to create public/private key pairs for elliptic curves. A threshold secret sharing scheme can be used as a decentralised trust mechanism with applications in identity validation, message decryption, and agreement empowerment. Decentralising trust means that there is no single point vulnerability which could enable compromise of a system. Our primary interest is in twisted Edwards curves as used in EdDSA, and the related Diffie-Hellman key-exchange algorithms. The key generation is also decentralised, so can be used as a decentralised secret RNG suitable for use in other algorithms. The algorithms presented could be used to fill a ``[TBS]'' in the draft IETF specification ``Threshold modes in elliptic curves'' published in 2020 and updated in 2022

    Lessons Learned Conducting Breastfeeding Intervention Research in Two Northern Plains Tribal Communities

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    AIM: The overall purpose of this article was to describe the challenges and benefits of conducting breastfeeding intervention research with two Native American Tribal communities. METHODS: A focus group with an interpretive approach was used to collect data within this qualitative study as a means of incorporating a complex, holistic, subjective interpretation of the case managers\u27 perceptions and experiences. In addition, researchers\u27 field notes were used. Findings are discussed in relation to Rogers\u27 Diffusion of Innovation Framework. RESULTS: Themes that emerged during the focus group discussions were related to innovation, relative advantage, complexity, compatibility, trialability, and observability. CONCLUSIONS: Conducting research in Native American Tribal communities was both enriching and challenging. The research protocol needs to be culturally appropriate, and complex components need to be videotaped for review on an ongoing basis. Time constraints of case managers need to be examined prior to development of the research protocol

    Lessons Learned Conducting Breastfeeding Intervention Research in Two Northern Plains Tribal Communities

    Get PDF
    AIM: The overall purpose of this article was to describe the challenges and benefits of conducting breastfeeding intervention research with two Native American Tribal communities. METHODS: A focus group with an interpretive approach was used to collect data within this qualitative study as a means of incorporating a complex, holistic, subjective interpretation of the case managers\u27 perceptions and experiences. In addition, researchers\u27 field notes were used. Findings are discussed in relation to Rogers\u27 Diffusion of Innovation Framework. RESULTS: Themes that emerged during the focus group discussions were related to innovation, relative advantage, complexity, compatibility, trialability, and observability. CONCLUSIONS: Conducting research in Native American Tribal communities was both enriching and challenging. The research protocol needs to be culturally appropriate, and complex components need to be videotaped for review on an ongoing basis. Time constraints of case managers need to be examined prior to development of the research protocol

    Aberrant expression of intestinal mucin antigens associated with colorectal carcinoma defined by a panel of monoclonal antibodies.

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    Small intestine mucin antigen (SIMA) is an oncofoetal antigen for the colon and is distinct from the normal large intestinal mucin antigen (LIMA). In the present study, a panel of anti-SIMA and anti-LIMA monoclonal antibodies (MAb) was used to charaterise altered mucin expression in colorectal adenocarcinomas, by immunohistochemistry and quantitative immunoassays of tissue extracts. These results are compared with CEA expression and correlated with various clinicopathological indices. All mucin MAb reacted with a high proportion of the 100 colon cancers of every stage, histological type (including non-mucinous cancers), differentiation, site, or size. Inappropriate SIMA production was detected by either anti-SIMA MAb 4D3 or 4A1, even in 85% of early stage cancers. MAb 4D3 reacted with a higher proportion of cancers of smaller size and better differentiation. At the subcellular level, both anti-SIMA MAb showed reactivity typical of normal mucin, i.e., goblet cell and extracellular mucin. The normal colonic antigen, LIMA, was also detectable in the majority of cases, but quantitatively overproduced in some cases and reduced in others. However, in contrast to SIMA, LIMA was detected in predominantly undifferentiated cancer cells but not in goblet cells. Heterogeneity of MAb reactivity between cases and complementarity within each cancer was frequently observed. Mucin reactive with at least one of the MAb was detected in all of the CEA-negative cancers. A high rate of inappropriate SIMA expression was also detected in the perineoplastic transitional mucosa (88%, c.f. CEA, 35%) and adjacent, morphologically normal mucosa (80% c.f. CEA, 24%), indicating biochemical changes similar to the cancer. This panel of anti-mucin MAb demonstrated altered mucin glycoprotein metabolism associated with the development and progression of most colorectal cancers, which emphasises their utility as indicators of neoplastic change in the colon, and their superiority to CEA

    A simple model to assess the impact of gravity waves on ice-crystal populations in the tropical tropopause layer

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    The role of gravity waves on microphysics of tropical cirrus clouds and air-parcel dehydration was studied using the combination of Lagrangian observations of temperature fluctuations and a 1.5D model. High-frequency measurements during isopycnal balloon flights were used to resolve the gravity-wave signals with periods ranging from a few days to 10 min. The detailed microphysical simulations with homogeneous freezing, sedimentation, and a crude horizontal mixing represent the slow ascent of air parcels in the tropical tropopause layer (TTL). A reference simulation describes the slow ascent of air parcels in the tropical tropopause layer, with nucleation occurring only below the cold-point tropopause with a small ice-crystal density. The inclusion of the gravity waves drastically modifies the vertical profile of low ice concentration and weak dehydration found during the ascent alone, with the increased ice-crystal number and size distribution agreeing better with observations. Numerous events of nucleation occur below and above the cold-point tropopause, efficiently restoring the relative humidity over ice to equilibrium with respect to the background temperature, as well as increasing the cloud fraction in the vicinity of the cold-point tropopause. The corresponding decrease in water vapor is estimated at 2 ppmv around the cold-point tropopause.</p

    MicroRNA-155 is induced during the macrophage inflammatory response

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    The mammalian inflammatory response to infection involves the induction of several hundred genes, a process that must be carefully regulated to achieve pathogen clearance and prevent the consequences of unregulated expression, such as cancer. Recently, microRNAs (miRNAs) have emerged as a class of gene expression regulators that has also been linked to cancer. However, the relationship between inflammation, innate immunity, and miRNA expression is just beginning to be explored. In the present study, we use microarray technology to identify miRNAs induced in primary murine macrophages after exposure to polyriboinosinic:polyribocytidylic acid or the cytokine IFN-{beta}. miR-155 was the only miRNA of those tested that was substantially up-regulated by both stimuli. It also was induced by several Toll-like receptor ligands through myeloid differentiation factor 88- or TRIF-dependent pathways, whereas up-regulation by IFNs was shown to involve TNF-{alpha} autocrine signaling. Pharmacological inhibition of the kinase JNK blocked induction of miR-155 in response to either polyriboinosinic:polyribocytidylic acid or TNF-{alpha}, suggesting that miR-155-inducing signals use the JNK pathway. Together, these findings characterize miR-155 as a common target of a broad range of inflammatory mediators. Importantly, because miR-155 is known to function as an oncogene, these observations identify a potential link between inflammation and cancer
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