103 research outputs found
A Diffusion-Based Approach to Geminate Recombination of Heme Proteins with Small Ligands
A model of postphotodissociative monomolecular (geminate) recombination of
heme proteins with small ligands (NO, O2 or CO) is represented. The
non-exponential decay with time for the probability to find a heme in unbound
state is interpreted in terms of diffusion-like migration of ligabs
physics/0212040 and between protein cavities. The temporal behavior for the
probability is obtained from numerical simulation and specified by two
parameters: the time \tau_{reb} of heme-ligand rebinding for the ligand
localized inside the heme pocket and the time \tau_{esc} of ligand escape from
the pocket. The model is applied in the analysis of available experimental data
for geminate reoxygenation of human hemoglobin HbA. Our simulation is in good
agreement with the measurements. The analysis shows that the variation in pH of
the solution (6.0<pH<9.4) results in considerable changes for \tau_{reb} from
0.36 ns (at pH=8.5) up to 0.5 ns (pH=6.0) but effects slightly on the time
\tau_{esc} (\tau_{esc} ~ 0.88 ns).Comment: 8 pages with 4 figures, submitted to Chem. Phy
The Maunakea Spectroscopic Explorer Book 2018
(Abridged) This is the Maunakea Spectroscopic Explorer 2018 book. It is
intended as a concise reference guide to all aspects of the scientific and
technical design of MSE, for the international astronomy and engineering
communities, and related agencies. The current version is a status report of
MSE's science goals and their practical implementation, following the System
Conceptual Design Review, held in January 2018. MSE is a planned 10-m class,
wide-field, optical and near-infrared facility, designed to enable
transformative science, while filling a critical missing gap in the emerging
international network of large-scale astronomical facilities. MSE is completely
dedicated to multi-object spectroscopy of samples of between thousands and
millions of astrophysical objects. It will lead the world in this arena, due to
its unique design capabilities: it will boast a large (11.25 m) aperture and
wide (1.52 sq. degree) field of view; it will have the capabilities to observe
at a wide range of spectral resolutions, from R2500 to R40,000, with massive
multiplexing (4332 spectra per exposure, with all spectral resolutions
available at all times), and an on-target observing efficiency of more than
80%. MSE will unveil the composition and dynamics of the faint Universe and is
designed to excel at precision studies of faint astrophysical phenomena. It
will also provide critical follow-up for multi-wavelength imaging surveys, such
as those of the Large Synoptic Survey Telescope, Gaia, Euclid, the Wide Field
Infrared Survey Telescope, the Square Kilometre Array, and the Next Generation
Very Large Array.Comment: 5 chapters, 160 pages, 107 figure
Repeated exposure to socioeconomic disadvantage and health selection as life course pathways to mid-life depressive and anxiety disorders
The biomedical examination was funded by
Medical Research Council [G0000934], awarded under the Health of
the Public initiative. Charlotte Clark is supported by an Engineering
and Physical Sciences Research Fellowship. Bryan Rodgers is supported
by Research Fellowships Nos 148948 and 366758 and by
Program Grant No. 179805 from the National Health and Medical
Research Council of Australia. Research at the Institute of Child
Health and Great Ormond Street Hospital for Children NHS Trust
benefits from R&D funding received from the NHS Executive
Evidence for a Common Mechanism of SIRT1 Regulation by Allosteric Activators
A molecule that treats multiple age-related diseases would have a major impact on global health and economics. The SIRT1 deacetylase has drawn attention in this regard as a target for drug design. Yet controversy exists around the mechanism of sirtuin-activating compounds (STACs). We found that specific hydrophobic motifs found in SIRT1 substrates such as PGC-1α and FOXO3a facilitate SIRT1 activation by STACs. A single amino acid in SIRT1, Glu[superscript 230], located in a structured N-terminal domain, was critical for activation by all previously reported STAC scaffolds and a new class of chemically distinct activators. In primary cells reconstituted with activation-defective SIRT1, the metabolic effects of STACs were blocked. Thus, SIRT1 can be directly activated through an allosteric mechanism common to chemically diverse STACs.Glenn Foundation for Medical ResearchEllison Medical FoundationJuvenile Diabetes Research Foundation InternationalUnited Mitochondrial Disease FoundationNational Institutes of Health (U.S.)National Institute of Allergy and Infectious Diseases (U.S.
The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Final Report
The Habitable Exoplanet Observatory, or HabEx, has been designed to be the Great Observatory of the 2030s. For the first time in human history, technologies have matured sufficiently to enable an affordable space-based telescope mission capable of discovering and characterizing Earthlike planets orbiting nearby bright sunlike stars in order to search for signs of habitability and biosignatures. Such a mission can also be equipped with instrumentation that will enable broad and exciting general astrophysics and planetary science not possible from current or planned facilities. HabEx is a space telescope with unique imaging and multi-object spectroscopic capabilities at wavelengths ranging from ultraviolet (UV) to near-IR. These capabilities allow for a broad suite of compelling science that cuts across the entire NASA astrophysics portfolio. HabEx has three primary science goals: (1) Seek out nearby worlds and explore their habitability; (2) Map out nearby planetary systems and understand the diversity of the worlds they contain; (3) Enable new explorations of astrophysical systems from our own solar system to external galaxies by extending our reach in the UV through near-IR. This Great Observatory science will be selected through a competed GO program, and will account for about 50% of the HabEx primary mission. The preferred HabEx architecture is a 4m, monolithic, off-axis telescope that is diffraction-limited at 0.4 microns and is in an L2 orbit. HabEx employs two starlight suppression systems: a coronagraph and a starshade, each with their own dedicated instrument
The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Final Report
The Habitable Exoplanet Observatory, or HabEx, has been designed to be the
Great Observatory of the 2030s. For the first time in human history,
technologies have matured sufficiently to enable an affordable space-based
telescope mission capable of discovering and characterizing Earthlike planets
orbiting nearby bright sunlike stars in order to search for signs of
habitability and biosignatures. Such a mission can also be equipped with
instrumentation that will enable broad and exciting general astrophysics and
planetary science not possible from current or planned facilities. HabEx is a
space telescope with unique imaging and multi-object spectroscopic capabilities
at wavelengths ranging from ultraviolet (UV) to near-IR. These capabilities
allow for a broad suite of compelling science that cuts across the entire NASA
astrophysics portfolio. HabEx has three primary science goals: (1) Seek out
nearby worlds and explore their habitability; (2) Map out nearby planetary
systems and understand the diversity of the worlds they contain; (3) Enable new
explorations of astrophysical systems from our own solar system to external
galaxies by extending our reach in the UV through near-IR. This Great
Observatory science will be selected through a competed GO program, and will
account for about 50% of the HabEx primary mission. The preferred HabEx
architecture is a 4m, monolithic, off-axis telescope that is
diffraction-limited at 0.4 microns and is in an L2 orbit. HabEx employs two
starlight suppression systems: a coronagraph and a starshade, each with their
own dedicated instrument.Comment: Full report: 498 pages. Executive Summary: 14 pages. More information
about HabEx can be found here: https://www.jpl.nasa.gov/habex
A framework to integrate design knowledge reuse and requirements management in engineering design
This paper presents a framework to integrate requirements management and design
knowledge reuse. The research approach begins with a literature review in design
reuse and requirements management to identify appropriate methods within each
domain. A framework is proposed based on the identified requirements. The
framework is then demonstrated using a case study example: vacuum pump design.
Requirements are presented as a component of the integrated design knowledge
framework. The proposed framework enables the application of requirements
management as a dynamic process, including capture, analysis and recording of
requirements. It takes account of the evolving requirements and the dynamic
nature of the interaction between requirements and product structure through the
various stages of product development. (C) 2007 Elsevier Ltd. All rights
reserved
An engineering design knowledge reuse methodology using process modelling.
This paper describes an approach for reusing engineering design knowledge. Many previous design knowledge reuse systems focus exclusively on geometrical data, which is often not applicable in early design stages. The proposed methodology provides an integrated design knowledge reuse framework, bringing together elements of best practice reuse, design rationale capture and knowledge-based support in a single coherent framework. Best practices are reused through the process model. Rationale is supported by product information, which is retrieved through links to design process tasks. Knowledge-based methods are supported by a common design data model, which serves as a single source of design data to support the design process. By using the design process as the basis for knowledge structuring and retrieval, it serves the dual purpose of design process capture and knowledge reuse: capturing and formalising the rationale that underpins the design process, and providing a framework through which design knowledge can be stored, retrieved and applied. The methodology has been tested with an industrial sponsor producing high vacuum pumps for the semiconductor industry
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