95 research outputs found
Recommended from our members
Targeting reserve growth opportunities in the northern Gulf of Mexico Basin: transferring secondary gas recovery technology to the offshore environment - book 2
The Bureau of Economic Geology's (BEG) Offshore Secondary Gas Recovery is a multi-fiscal-year project funded by the U.S. Department of Energy, whose goal is to research new techniques for defining the structure, stratigraphy, and hydrocarbons in a mature area in the northern Gulf of Mexico and to utilize those multidisciplinary methods to identify additional gas resources, as well as predict regional trends in hydrocarbon accumulation. Phases 1 and 2 of the project work plan (Project Preparation and Data Gathering and Loading, respectively) are completed. Phase 3 of the plan (Data Analysis) is 65 percent completed, with all third- and fourth-order key surfaces mapped in the log data. Sixty fourth-order and twelve third-order sequences have been defined using well data, and key flooding surfaces have been mapped in the seismic volume. Structural mapping of 13 key horizons is completed and provides a structural framework within which to look at production and reservoir development. The sequence framework is complete within and immediately between the two fields and provides a basis for examining hydrocarbon occurrence and distribution. Structural slices of the seismic amplitude data volume have been completed at 4-ms intervals through the data, providing detailed maps of amplitude anomalies associated with quality reservoirs. The process of transforming the seismic attribute volume into a three-dimensional petrophysical volume is progressing, and the addition of an engineer in FY 2001 will initiate development of a fourth-order-level reservoir-flow model within a carefully chosen subset of the data volume.Bureau of Economic Geolog
The structure of epitaxial V2O3 films and their surfaces : a medium energy ion scattering study
Medium energy ion scattering, using 100 keV H+ incident ions, has been used to investigate the growth of epitaxial films, up to thicknesses of ~200 Å, of V2O3 on both Pd(111) and Au(111). Scattered-ion energy spectra provide a measure of the average film thickness and the variations in this thickness, and show that, with suitable annealing, the crystalline quality is good. Plots of the scattering yield as a function of scattering angle, so-called blocking curves, have been measured for two different incidence directions and have been used to determine the surface structure. Specifically, scattering simulations for a range of different model structures show poor agreement with experiment for half-metal (….V’O3V) and vanadyl (….V’O3V=O) terminations, with and without surface interlayer relaxations. However, good agreement with experiment is found for the modified oxygen-termination structure, first proposed by Kresse et al., in which a subsurface V half-metal layer is moved up into the outermost V buckled metal layer to produce a VO2 overlayer on the underlying V2O3, with an associated layer structure of ….O3VV’’V’O3
Recommended from our members
Targeting reserve growth opportunities in the northern Gulf of Mexico Basin: transferring secondary gas recovery technology to the offshore environment Book 1
The Bureau of Economic Geology's Offshore Secondary Gas Recovery project is a multi-fiscal-year project funded by the U.S. Department of Energy, whose goal is to identify additional natural gas resources in a major field in the northern Gulf of Mexico Basin through multidisciplinary field and reservoir characterization study. Phases 1 and 2 of the project work plan (Project Preparation and Data Gathering and Loading, respectively) are nearly complete and scheduled to be completed by the end of October 1999. Phase 3 of the plan (Data Analysis) is well underway, and a list of preliminary leads is currently being compiled to convey to our industry partner. Reservoir tops have been spotted to facilitate production evaluation and recompletion opportunity. Key regional sequence surfaces have been identified in well logs and seismic, and mapping is being completed in the seismic dataset. Some of these surfaces have provided horizons to initiate a continuity processing of the seismic data volume for mapping depositional architecture. Well log interpretation of stacking patterns and systems tracts is well underway. Correlation surfaces have been compiled, and cross sections have been generated and interpreted for depositional elements. These data are being integrated with seismic data via Landmark® software. The project is on track within its projected timeframe, and additional personnel are being added as per the technical analysis plan. The key objective in the next fiscal year is to do the bulk of the technical analysis, focusing on generating a prioritized portfolio of infill and exploration prospects. Direct hydrocarbon indicator (DHI) modeling and analysis, continuity and impedance analysis, a general attribute interpretation of the seismic data, continued log-facies and parasequence interpretation, fault-seal analysis, and rigorous petrophysical analysis of well data are critical components of this objective.Bureau of Economic Geolog
A Systematic Review and Meta-analysis of the Impact of Radiation-Related Lymphopenia on Outcomes in High-Grade Gliomas
Introduction Malignant gliomas are the most common primary malignant brain tumors and are typically treated with maximal safe surgical resection followed by chemoradiation. One of the unintended effects of radiation is depletion of circulating lymphocyte pool, which has been correlated with inferior overall survival outcomes.
Methods A comprehensive and systematic searches of the PubMed, Cochrane Central, and Embase databases were done to assess the studies that have reported radiation-related lymphopenia in high-grade gliomas. Hazard ratios (HRs), odds ratios (OR), and mean differences were represented with Forest plots comparing patients with severe lymphopenia and no severe lymphopenia. Review Manager Version 5.3 (The Nordic Cochrane Centre, Copenhagen, Denmark) was used for the analysis.
Results Nineteen studies were included in the final systematic review and 12 studies were included in the meta-analysis. The odds of developing severe lymphopenia were 0.39 (95% CI:0.19, 0.81, I 2 = 94%, p = 0.01). Patients with severe lymphopenia were at increased risk of death with a pooled HR = 2.19 (95% CI: 1.70, 2.83, I 2 = 0%, p \u3c0.00001) compared to patients with no severe lymphopenia. The mean difference in survival between patients with severe lymphopenia and no severe lymphopenia was −6.72 months (95% CI: −8.95, −4.49, I 2 = 99%, p \u3c0.00001), with a better mean survival in the no severe lymphopenia group.
Conclusion Radiation-induced severe lymphopenia was associated with poor overall survival and increased risk of death. Photon therapy, larger planning target volume, higher brain dose, higher hypothalamus dose, and female gender were associated with increased risk of severe lymphopenia
Developmental Regulation of Genes Encoding Universal Stress Proteins in Schistosoma mansoni
The draft nuclear genome sequence of the snail-transmitted, dimorphic, parasitic, platyhelminth Schistosoma mansoni revealed eight genes encoding proteins that contain the Universal Stress Protein (USP) domain. Schistosoma mansoni is a causative agent of human schistosomiasis, a severe and debilitating Neglected Tropical Disease (NTD) of poverty, which is endemic in at least 76 countries. The availability of the genome sequences of Schistosoma species presents opportunities for bioinformatics and genomics analyses of associated gene families that could be targets for understanding schistosomiasis ecology, intervention, prevention and control. Proteins with the USP domain are known to provide bacteria, archaea, fungi, protists and plants with the ability to respond to diverse environmental stresses. In this research investigation, the functional annotations of the USP genes and predicted nucleotide and protein sequences were initially verified. Subsequently, sequence clusters and distinctive features of the sequences were determined. A total of twelve ligand binding sites were predicted based on alignment to the ATP-binding universal stress protein from Methanocaldococcus jannaschii. In addition, six USP sequences showed the presence of ATP-binding motif residues indicating that they may be regulated by ATP. Public domain gene expression data and RT-PCR assays confirmed that all the S. mansoni USP genes were transcribed in at least one of the developmental life cycle stages of the helminth. Six of these genes were up-regulated in the miracidium, a free-swimming stage that is critical for transmission to the snail intermediate host. It is possible that during the intra-snail stages, S. mansoni gene transcripts for universal stress proteins are low abundant and are induced to perform specialized functions triggered by environmental stressors such as oxidative stress due to hydrogen peroxide that is present in the snail hemocytes. This report serves to catalyze the formation of a network of researchers to understand the function and regulation of the universal stress proteins encoded in genomes of schistosomes and their snail intermediate hosts
Recurrence of Dupuytren’s contracture: A consensus-based definition
Purpose: One of the major determinants of Dupyutren disease (DD) treatment efficacy is recurrence of the contracture. Unfortunately, lack of agreement in the literature on what constitutes recurrence makes it nearly impossible to compare the multiple treatments alternatives available today. The aim of this study is to bring an unbiased pool of experts to agree upon what would be considered a recurrence of DD after treatment; and from that consensus establish a much-needed definition for DD recurrence. Methods: To reach an expert consensus on the definition of recurrence we used the Delphi method and invited 43 Dupuytren’s research and treatment experts from 10 countries to participate by answering a series of questionnaire rounds. After each round the answers were analyzed and the experts received a feedback report with another questionnaire round to further hone in of the definition. We defined consensus when at least 70% of the experts agreed on a topic. Results: Twenty-one experts agreed to participate in this study. After four consensus rounds, we agreed that DD recurrence should be defined as “more than 20 degrees of contracture recurrence in any treated joint at one year post-treatment compared to six weeks post-treatment”. In addition, “recurrence should be reported individually for every treated joint” and afterwards measurements should be repeated and reported yearly. Conclusion: This study provides the most comprehensive to date definition of what should be considered recurrence of DD. These standardized criteria should allow us to better evaluate the many treatment alternatives
The emerging landscape of single-molecule protein sequencing technologies
Single-cell profiling methods have had a profound impact on the understanding of cellular heterogeneity. While genomes and transcriptomes can be explored at the single-cell level, single-cell profiling of proteomes is not yet established. Here we describe new single-molecule protein sequencing and identification technologies alongside innovations in mass spectrometry that will eventually enable broad sequence coverage in single-cell profiling. These technologies will in turn facilitate biological discovery and open new avenues for ultrasensitive disease diagnostics.This Perspective describes new single-molecule protein sequencing and identification technologies alongside innovations in mass spectrometry that will eventually enable broad sequence coverage in single-cell proteomics.</p
Frequency fluctuations in silicon nanoresonators
Frequency stability is key to performance of nanoresonators. This stability
is thought to reach a limit with the resonator's ability to resolve
thermally-induced vibrations. Although measurements and predictions of
resonator stability usually disregard fluctuations in the mechanical frequency
response, these fluctuations have recently attracted considerable theoretical
interest. However, their existence is very difficult to demonstrate
experimentally. Here, through a literature review, we show that all studies of
frequency stability report values several orders of magnitude larger than the
limit imposed by thermomechanical noise. We studied a monocrystalline silicon
nanoresonator at room temperature, and found a similar discrepancy. We propose
a new method to show this was due to the presence of frequency fluctuations, of
unexpected level. The fluctuations were not due to the instrumentation system,
or to any other of the known sources investigated. These results challenge our
current understanding of frequency fluctuations and call for a change in
practices
- …