38,754 research outputs found
Characterization of the Influences of Human Cytomegalovirus Glycoprotein O (gO) Expression on gH/gL Complexes Assembly and Its Polymorphisms on Cell-free and Cell-to-cell Spread, and Antibody Neutralization.
Human cytomegalovirus (HCMV) is widely spread throughout the world and immunocompromised individuals can suffer severe diseases from HCMV infection. Once the infection is established, HCMV can spread through the body and infect many major somatic cell types. The glycoproteins H and L (gH/gL) on HCMV envelope can be bound by either gO or the UL128-131 proteins to form complexes gH/gL/gO and gH/gL/UL128-131 that are critical for viral entry and spread, and these two complexes are important targets of neutralizing antibodies. Strains of HCMV vary considerably in the levels of gH/gL/gO and gH/gL/UL128-131. gO is one of the most diverse loci among strains with 10-30% of amino acid sequence differences. In this thesis I explored the mechanisms behind the complex assembly differences between strains and the impacts of interstrain gO diversity on the biology of HCMV. My results uncovered that the strain variations in the assembly of gH/gL complexes is due to the differences in the expression level of gO and UL128-131, while gO amino acid sequence differences have no influence on the complexes assembly. Interestingly, the diversity of gO has dramatic impacts on HCMV cell-free and cell-to-cell spread as well as on antibody neutralization and these effects of gO polymorphisms are epistatically dependent on other variable loci in the virus genome. My study could help to understand the complexity of genotypes observed in clinical samples and decode the challenge for intervention approaches against HCMV
Sub-100 attoseconds optics-to-microwave synchronization
We use two fiber-based femtosecond frequency combs and a low-noise carrier
suppression phase detection system to characterize the optical to microwave
synchronization achievable with such frequency divider systems. By applying
specific noise reduction strategies, a residual phase noise as low as -120
dBc/Hz at 1 Hz offset frequency from a 11.55 GHz carrier is measured. The
fractional frequency instability from a single optical-to-frequency divider is
1.1E-16 at 1 s averaging down to below 2E-19 after only 1000 s. The
corresponding rms time deviation is lower than 100 attoseconds up to 1000 s
averaging duration.Comment: 4 pages, 3 figure
An ultrafast 1 x M all-optical WDM packet-switched router based on the PPM header address
This paper presents an all-optical 1 x M WDM router architecture for packet routing at multiple wavelengths simultaneously, with no wavelength conversion modules. The packet header address adopted is based on the pulse position modulation (PPM) format, thus enabling the use of only a singlebitwise optical AND gate for fast header address correlation. It offers multicast as well as broadcast capabilities. It is shown that a high speed packet routing at 160 Gb/s can be achieved with a low channel crosstalk (CXT) of ~ -27 dB at a channel spacing of greater than 0.4 THz and a demultiplexer bandwidth of 500 GHz
Australopithecus afarensis endocasts suggest ape-like brain organization and prolonged brain growth
Human brains are three times larger, are organized differently, and mature for a longer period of time than those of our closest living relatives, the chimpanzees. Together, these characteristics are important for human cognition and social behavior, but their evolutionary origins remain unclear. To study brain growth and organization in the hominin species Australopithecus afarensis more than 3 million years ago, we scanned eight fossil crania using conventional and synchrotron computed tomography. We inferred key features of brain organization from endocranial imprints and explored the pattern of brain growth by combining new endocranial volume estimates with narrow age at death estimates for two infants. Contrary to previous claims, sulcal imprints reveal an ape-like brain organization and no features derived toward humans. A comparison of infant to adult endocranial volumes indicates protracted brain growth in A. afarensis, likely critical for the evolution of a long period of childhood learning in hominins
From Design to Production Control Through the Integration of Engineering Data Management and Workflow Management Systems
At a time when many companies are under pressure to reduce "times-to-market"
the management of product information from the early stages of design through
assembly to manufacture and production has become increasingly important.
Similarly in the construction of high energy physics devices the collection of
(often evolving) engineering data is central to the subsequent physics
analysis. Traditionally in industry design engineers have employed Engineering
Data Management Systems (also called Product Data Management Systems) to
coordinate and control access to documented versions of product designs.
However, these systems provide control only at the collaborative design level
and are seldom used beyond design. Workflow management systems, on the other
hand, are employed in industry to coordinate and support the more complex and
repeatable work processes of the production environment. Commercial workflow
products cannot support the highly dynamic activities found both in the design
stages of product development and in rapidly evolving workflow definitions. The
integration of Product Data Management with Workflow Management can provide
support for product development from initial CAD/CAM collaborative design
through to the support and optimisation of production workflow activities. This
paper investigates this integration and proposes a philosophy for the support
of product data throughout the full development and production lifecycle and
demonstrates its usefulness in the construction of CMS detectors.Comment: 18 pages, 13 figure
Stability of 3D Cubic Fixed Point in Two-Coupling-Constant \phi^4-Theory
For an anisotropic euclidean -theory with two interactions [u
(\sum_{i=1^M {\phi}_i^2)^2+v \sum_{i=1}^M \phi_i^4] the -functions are
calculated from five-loop perturbation expansions in
dimensions, using the knowledge of the large-order behavior and Borel
transformations. For , an infrared stable cubic fixed point for
is found, implying that the critical exponents in the magnetic phase
transition of real crystals are of the cubic universality class. There were
previous indications of the stability based either on lower-loop expansions or
on less reliable Pad\'{e approximations, but only the evidence presented in
this work seems to be sufficently convincing to draw this conclusion.Comment: Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Paper also at
http://www.physik.fu-berlin.de/~kleinert/kleiner_re250/preprint.htm
Tanning bed use and melanoma: Establishing risk and improving prevention interventions
AbstractPurposeExposure to ultraviolet radiation (UVR) from indoor tanning devices is thought to cause melanoma and other negative health consequences. Despite these findings, the practice of indoor tanning in the United States remains prevalent. In this paper we aim to present a clear discussion of the relationship between indoor tanning and melanoma risk, and to identify potential strategies for effective melanoma prevention by addressing indoor tanning device use.Basic proceduresWe reviewed relevant literature on the risks of indoor tanning, current indoor tanning legislation, and trends in indoor tanning and melanoma incidence. Study was conducted at the University of Southern California, Los Angeles, CA between the years of 2014 and 2015.Main findingsOur findings reaffirm the relationship between indoor tanning and melanoma risk, and suggest a widespread public misunderstanding of the negative effects of indoor tanning.Principal conclusionsThis review argues for an aggressive initiative to reduce indoor tanning in the United States, to design prevention efforts tailored towards specific high risk groups, and the need to better inform the public of the risks of indoor tanning
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