768 research outputs found
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Offshore CO2 storage resource assessment of the northern Gulf of Mexico (Texas-Louisiana)
The Offshore CO2 Storage Resource Assessment of the Northern Gulf of Mexico (Texas-Louisiana) project (a.k.a., "TXLA" study) supports Goals 3 & 4 of the DOE NETL Carbon Storage Program Plan by aiding industry's ability to predict CO2 storage capacity in geologic formations to within +/- 30%. This is achieved by assessing potential regional storage formations in the State and federally regulated portions of the Gulf of Mexico.
The objective of the project was to conduct an offshore carbon storage resource assessment of the Gulf of Mexico, Texas — Louisiana study area. This was accomplished by:
1. Assessing the carbon dioxide (CO2) storage capacity of depleted oil and natural gas reservoirs utilizing existing data (well logs, records and sample descriptions from existing or plugged/abandoned wells, available seismic surveys, existing core samples, and other available geologic and laboratory data) from historical hydrocarbon industry activities in the heavily explored portions of the inner continental shelf portions of the Texas and Louisiana Gulf of Mexico coastal areas.
2. Assessing the ability and capacity of saline formations in the region to safely and permanently store nationally-significant amounts of anthropogenic CO2 using existing data.
Additionally, the study identified at least one specific site with the potential to store at least 30 million tonnes of CO2, which may be considered in the future for commercial or integrated demonstration projects. The study also engaged the public and other stakeholders in the region through outreach activities to apprise them of the study objectives and results.Bureau of Economic Geolog
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Comparing carbon sequestration in an oil reservoir to sequestration in a brine formation-field study
Geologic sequestration of CO2 in an oil reservoir is generally considered a different class than sequestration in
formations which contain only brine. In this paper, the significance and validity of this conceptualization is
examined by comparing the performance of CO2 injected into a depleted oil reservoir with the performance of
similar injection into non-oil bearing sandstones using a field test at Cranfield Field, Mississippi as a case study. The
differences considered are:
(1)Residual oil in the reservoir slightly reduces the CO2 breakthrough time and rate of pressure build up as
compared to a reservoir containing only brine, because under miscible conditions, more CO2 dissolves into oil
than in to brine.
(2)Dense wells provide improved assessment of the oil reservoir quality leading to improved prediction as well as
verification of CO2 movement in this reservoir as compared to the sparsely characterized brine leg. The value of
this information exceeds the risk of leakage.
Assessment of the difference made by the presence of residual oil requires a good understanding reservoir properties
to predict oil and gas distribution. Stratal slicing, attribute analysis and petrographic analyses are used to define the
reservoir architecture. Real-time pressure response at a dedicated observation well and episodic pressure mapping
has been conducted in the reservoir under flood since mid-2008; comparison measurements are planned for 2009 in
down-dip environments lacking hydrocarbons. Model results using GEM compositional simulator compare well in
general to measured reservoir response under CO2 flood; imperfections in model match of flood history document
uncertainties Time laps RST logging is underway to validate fluid composition and migration models. Monitoring
assessing the performance of the wells during the injection of CO2 suggests that the value of wells to provide field
data for characterization exceeds the risk of leakage.Bureau of Economic Geolog
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High Frequency (4th order) Sequence Stratigraphy of Early Miocene Deltaic Shorelines, Offshore Texas and Louisiana
DOE-NETL Award Numbers DE-FE0026083 and DEFE0029487Bureau of Economic Geolog
PVP-coated silver nanoparticles block the transmission of cell-free and cell-associated HIV-1 in human cervical culture
<p>Abstract</p> <p>Background</p> <p>Previous <it>in vitro </it>studies have demonstrated that polyvinylpyrrolidone coated silver nanoparticles (PVP-coated AgNPs) have antiviral activity against HIV-1 at non-cytotoxic concentrations. These particles also demonstrate broad spectrum virucidal activity by preventing the interaction of HIV-1 gp120 and cellular CD4, thereby inhibiting fusion or entry of the virus into the host cell. In this study, we evaluated the antiviral activity of PVP-coated AgNPs as a potential topical vaginal microbicide to prevent transmission of HIV-1 infection using human cervical culture, an <it>in vitro </it>model that simulates <it>in vivo </it>conditions.</p> <p>Results</p> <p>When formulated into a non-spermicidal gel (Replens) at a concentration of 0.15 mg/mL, PVP-coated AgNPs prevented the transmission of cell-associated HIV-1 and cell-free HIV-1 isolates. Importantly, PVP-coated AgNPs were not toxic to the explant, even when the cervical tissues were exposed continuously to 0.15 mg/mL of PVP-coated AgNPs for 48 h. Only 1 min of PVP-coated AgNPs pretreatment to the explant was required to prevent transmission of HIV-1. Pre-treatment of the cervical explant with 0.15 mg/mL PVP-coated AgNPs for 20 min followed by extensive washing prevented the transmission of HIV-1 in this model for 48 h.</p> <p>Conclusions</p> <p>A formulation of PVP-coated AgNPs homogenized in Replens gel acts rapidly to inhibit HIV-1 transmission after 1 min and offers long-lasting protection of the cervical tissue from infection for 48 h, with no evidence of cytotoxicity observed in the explants.</p> <p>Based on this data, PVP-coated AgNPs are a promising microbicidal candidate for use in topical vaginal/cervical agents to prevent HIV-1 transmission, and further research is warranted.</p
Use of silver nanoparticles increased inhibition of cell-associated HIV-1 infection by neutralizing antibodies developed against HIV-1 envelope proteins
<p>Abstract</p> <p>Background</p> <p>HIV/AIDS pandemic is a worldwide public health issue. There is a need for new approaches to develop new antiviral compounds or other therapeutic strategies to limit viral transmission. The envelope glycoproteins gp120 and gp41 of HIV are the main targets for both silver nanoparticles (AgNPs) and neutralizing antibodies. There is an urgency to optimize the efficiency of the neutralizing antibodies (NABs). In this study, we demonstrated that there is an additive effect between the four NABs and AgNPs when combined against cell-associated HIV-1 infection <it>in vitro</it></p> <p>Results</p> <p>Four NABs (Monoclonal antibody to HIV-1 gp41 126-7, HIV-1 gp120 Antiserum PB1 Sub 2, HIV-1 gp120 Antiserum PB1, HIV-1 gp120 Monoclonal Antibody F425 B4e8) with or without AgNPs of 30-50 nm in size were tested against cell free and cell-associated HIV<sub>IIIB </sub>virus. All NABs inhibited HIV-1 cell free infection at a dose response manner, but with AgNPs an antiviral additive effect was not achieved Although there was no inhibition of infection with cell-associated virus by the NABs itself, AgNPs alone were able to inhibit cell associated virus infection and more importantly, when mixed together with NABs they inhibited the HIV-1 cell associated infection in an additive manner.</p> <p>Discussion</p> <p>The most attractive strategies to deal with the HIV problem are the development of a prophylactic vaccine and the development of effective topical vaginal microbicide. For two decades a potent vaccine that inhibits transmission of infection of HIV has been searched. There are vaccines that elicit NABs but none of them has the efficacy to stop transmission of HIV-1 infection. We propose that with the addition of AgNPs, NABs will have an additive effect and become more potent to inhibit cell-associated HIV-1 transmission/infection.</p> <p>Conclusions</p> <p>The addition of AgNPs to NABs has significantly increased the neutralizing potency of NABs in prevention of cell-associated HIV-1 transmission/infection. Further exploration is required to standardize potentiation of NABs by AgNPs. It is also required to evaluate in vivo toxicity of AgNPs before AgNPs could be incorporated in any antiviral vaginal creams.</p
Square-tiled cyclic covers
A cyclic cover of the complex projective line branched at four appropriate
points has a natural structure of a square-tiled surface. We describe the
combinatorics of such a square-tiled surface, the geometry of the corresponding
Teichm\"uller curve, and compute the Lyapunov exponents of the determinant
bundle over the Teichm\"uller curve with respect to the geodesic flow. This
paper includes a new example (announced by G. Forni and C. Matheus in
\cite{Forni:Matheus}) of a Teichm\"uller curve of a square-tiled cyclic cover
in a stratum of Abelian differentials in genus four with a maximally degenerate
Kontsevich--Zorich spectrum (the only known example found previously by Forni
in genus three also corresponds to a square-tiled cyclic cover
\cite{ForniSurvey}).
We present several new examples of Teichm\"uller curves in strata of
holomorphic and meromorphic quadratic differentials with maximally degenerate
Kontsevich--Zorich spectrum. Presumably, these examples cover all possible
Teichm\"uller curves with maximally degenerate spectrum. We prove that this is
indeed the case within the class of square-tiled cyclic covers.Comment: 34 pages, 6 figures. Final version incorporating referees comments.
In particular, a gap in the previous version was corrected. This file uses
the journal's class file (jmd.cls), so that it is very similar to published
versio
How does ethical leadership trickle down? Test of an integrative dual-process model
Although the trickle-down effect of ethical leadership has been documented in the literature, its underlying mechanism still remains largely unclear. To address this gap, we develop a cross-level dual-process model to explain how the effect occurs. Drawing on social learning theory, we hypothesize that the ethical leadership of high-level managers could cascade to middle-level supervisors via its impact on middle-level supervisors’ two ethical expectations. Using a sample of 69 middle-level supervisors and 381 subordinates across 69 sub-branches from a large banking firm in China, we found that middle-level supervisors’ ethical efficacy expectation and unethical behavior–punishment expectation (as one form of ethical outcome expectations) accounted for the trickle-down effect. The explanatory role of middle-level supervisors’ ethical behavior–reward expectation (as the other form of ethical outcome expectations), however, was not supported. The theoretical and practical implications are discussed
Embedding clinical interventions into observational studies
Novel approaches to observational studies and clinical trials could improve the cost-effectiveness and speed of translation of research. Hybrid designs that combine elements of clinical trials with observational registries or cohort studies should be considered as part of a long-term strategy to transform clinical trials and epidemiology, adapting to the opportunities of big data and the challenges of constrained budgets. Important considerations include study aims, timing, breadth and depth of the existing infrastructure that can be leveraged, participant burden, likely participation rate and available sample size in the cohort, required sample size for the trial, and investigator expertise. Community engagement and stakeholder (including study participants) support are essential for these efforts to succeed
MicroRNAs in colorectal cancer
Colorectal cancer (CRC) is the third most common type of cancer worldwide, currently representing the most common gastrointestinal cancer with 13% of all malignant tumors. MicroRNAs (miRNAs) are small non-coding RNAs that repress the translation of target genes. Since their discovery, they have been shown to play an important role in the development of cancer, since they can act as tumor suppressors or oncogenes. A literature review was performed in different databases such as Medline, PubMed, Cochrane, nature, Wolters Kluwer, ScienceDirect, Scopus, SpringerLink, Wiley Online Library. Studies were included from 2003 to 2018. Colorectal cancer presents genetic heterogeneity, because it can develop in different ways, the pathway through which cancer occurs depends on the gene initially altered. The aberrant expression of microRNAs is implicated in the development of colorectal cancer and its progression. Three existing steps in the maturation of the microRNAs have been identified: 1) transcription of the pri-miRNA, 2) cleavage in the nucleus to form the pre-miRNA and 3) a final excision in the cytoplasm to form the mature microRNA. It has been discovered that miRNAs have an impact on cell proliferation, apoptosis, stress response, maintenance of stem cell potency and metabolism, all important factors in the etiology of cancer. The data analyzed in this article highlights the importance of the study of microRNAs in colorectal cancer, however, for the carcinogenic process, progression, therapeutic management and prognosis, more multicenter randomized clinical trials are needed with a detailed analysis
Clinical and immunological assessment in breast cancer patients receiving anticancer therapy and bovine dialyzable leukocyte extract as an adjuvant
Dialyzable leukocyte extract (DLE) is one of the immunological agents used as an adjuvant in cancer therapy; it has been associated with improved quality of life during cancer chemotherapy. Based on these previous findings and on the observed clinical benefits attributed to DLE in other types of cancer, we investigated its clinical and immunological effects as a therapy adjuvant on breast cancer patients who received only chemotherapy, as compared to patients administered bovine DLE (bDLE) as an adjuvant. This study included 43 breast cancer patients who were about to begin chemotherapy. This group was divided as follows: 25 received chemotherapy and bDLE as an adjuvant therapy, and 18 received only chemotherapy without the adjuvant. All patient clinical and immunological responses were monitored. Among patients in the group that received bDLE as adjuvant, 60% showed a complete response, 32% showed a partial response and 8% did not respond. By contrast, in the group without the adjuvant, 39% showed a complete response, 50% displayed a partial response and 11% were non-responders. In addition, bDLE treatment in combination with chemotherapy resulted in the enhancement of the Karnofsky performance scale during chemotherapy. Even though patients underwent several cycles of chemotherapy without bDLE, the lymphocyte population dropped to below the reference value. On the other hand, in patients with bDLE as adjuvant, the CD4(+) and CD8(+) lymphocytes and the B lymphocytes were maintained within the median range of the reference value. The number of natural killer cells also increased after chemotherapy treatment with bDLE as an adjuvant. In conclusion, bDLE treatment contributes to significant immunological recovery in patients that have undergone heavy chemotherapy, increasing the clinical response and quality of life during chemotherapy
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