3,136 research outputs found
Characterization, cloning and immunogenicity of antigens released by lung-stage larvae of Schistosoma mansoni
Lung-stage schistosomula are the target of protective immunity in mice vaccinated with attenuated cercariae of Schistosoma mansoni. Therefore, proteins present at this developmental stage, and in particular those which are secreted, are a potential source of novel vaccine candidates. However, little information is available about such molecules. Here we describe the cDNA clones identified by screening expression libraries with serum raised against proteins released by lung-stage schistosomula. In total, 11 different cDNA species were identified, 6 of which have been described previously in S. mansoni; these included fructose 1,6-bisphosphate aldolase and Sm21.7 which together accounted for two-thirds of all positive clones. Of the 5 newly described schistosome genes, 1 cDNA had a high degree of homology to the s5a subunit of 26S proteasomes, most significant being with the human protein. The remaining 4 clones showed no significant homologies to any genes sequenced previously. Fructose 1,6-bisphosphate aldolase, Sm21.7, the proteasome homologue and 1 unknown clone (A26) have been expressed in a bacterial expression system and serum produced against each recombinant protein. Immunolocalization showed fructose 1,6-bisphosphate aldolase, Sm21.7 and the proteasome homologue to be most abundant in muscle cells whilst clone A26 was distributed throughout many tissues, but was most abundant in the tegument. Analysis of the cellular immune responses of vaccinated mice showed 3 of the 4 expressed clones to be highly immunogenic, inducing the secretion of large quantities of the Th1-type cytokine interferon gamma
Avoidance of the real and anxiety about the unreal: attachment style and video-gaming
In this article, the authors discuss the light and dark side of attachments and attachment style in physical and digital worlds. They argue that many games offer opportunities for the generation of new and meaningful attachments to both physical and digital others. They discuss two ‘fundamental attachment errors’ and show how these can lead to both ‘light’ outcomes, in terms of opportunities to learn more secure attachment patterns, and ‘dark’ outcomes, where existing dysfunctional behaviours become more pronounced. The authors argue that the avatars which children adopt online have important consequences for their psychosocial development, and that these are mediated through the degree to which the real self is differentiated from the avatar. It is proposed that attachment is a key force in understanding play, and that studying its manifestations and effects in digital playscapes may contribute to understanding the effects of life online, and how insecure attachments may become secure
Tourism, migration, and the exodus to virtual worlds: place attachment in massively multiplayer online gamers
Place attachment to both physical and virtual places was investigated in an online survey of massively multiplayer online gamers. Participants (N=740) completed a place attachment inventory once for the place in the physical world which they considered home, and once for a place in a virtual world they felt attached to. In addition, measures of personality, gaming motivation, life satisfaction, attachment style, and identification with online avatars were taken. Results suggested that place identity, place uniqueness, and place social bonding were higher for physical places than for virtual places, but that place affect was higher for virtual places. A small number of participants (N=55, 7%) identified virtual ‘homes’, which participants felt were more special and which they identified more strongly with than other virtual places, and that were as unique and associated with an equal sense of belonging to physical homes. Results are interpreted through the lens of migration theory, and recommendations made for future research into digital domiciles and migration
A sensory-guided surgical micro-drill
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 The Authors.This article describes a surgical robotic device that is able to discriminate tissue interfaces and other controlling parameters ahead of the drill tip. The advantage in such a surgery is that the tissues at the interfaces can be preserved. A smart tool detects ahead of the tool point and is able to control the interaction with respect to the flexing tissue, to avoid penetration or to control the extent of protrusion with respect to the position of the tissue. For surgical procedures, where precision is required, the tool offers significant benefit. To interpret the drilling conditions and the conditions leading up to breakthrough at a tissue interface, a sensing scheme is used that discriminates between the variety of conditions posed in the drilling environment. The result is a fully autonomous system, which is able to respond to the tissue type, behaviour, and deflection in real-time. The system is also robust in terms of disturbances encountered in the operating theatre. The device is pragmatic. It is intuitive to use, efficient to set up, and uses standard drill bits. The micro-drill, which has been used to prepare cochleostomies in the theatre, was used to remove the bone tissue leaving the endosteal membrane intact. This has enabled the preservation of sterility and the drilling debris to be removed prior to the insertion of the electrode. It is expected that this technique will promote the preservation of hearing and reduce the possibility of complications. The article describes the device (including simulated drill progress and hardware set-up) and the stages leading up to its use in the theatre.Queen Elizabeth Hospital, Birmingham, U
Energy dependence on fractional charge for strongly interacting subsystems
The energies of a pair of strongly-interacting subsystems with arbitrary
noninteger charges are examined from closed and open system perspectives. An
ensemble representation of the charge dependence is derived, valid at all
interaction strengths. Transforming from resonance-state ionicity to ensemble
charge dependence imposes physical constraints on the occupation numbers in the
strong-interaction limit. For open systems, the chemical potential is evaluated
using microscopic and thermodynamic models, leading to a novel correlation
between ground-state charge and an electronic temperature.Comment: 4 pages, 3 figs.; as accepted (Phys. Rev. Lett.
Attachment, attraction and communication in real and virtual worlds: a study of massively multiplayer online gamers
Potential differences between relationships formed in online versus offline venues were explored using an online survey of massively multiplayer online gamers. Participants (N=1654) provided information about two or more relationships (kin, friends, and romantic relationships), indicating whether these had originated in online or offline venues. Attachment, attraction and communication were assessed for each relationship. Relationship security was predicted by attraction, but the effects of venue were limited to avoidance towards online romantic relationships. Personality, gaming motivation, age and sex all made negligible contributions to relationship security. Limitations, including the correlational nature of the data and the high proportion of male participants, as well as suggestions for how relationship research might proceed in an increasingly online world, are discussed
Sub-millimeter images of a dusty Kuiper belt around eta Corvi
We present sub-millimeter and mid-infrared images of the circumstellar disk
around the nearby F2V star eta Corvi. The disk is resolved at 850um with a size
of ~100AU. At 450um the emission is found to be extended at all position
angles, with significant elongation along a position angle of 130+-10deg; at
the highest resolution (9.3") this emission is resolved into two peaks which
are to within the uncertainties offset symmetrically from the star at 100AU
projected separation. Modeling the appearance of emission from a narrow ring in
the sub-mm images shows the observed structure cannot be caused by an edge-on
or face-on axisymmetric ring; the observations are consistent with a ring of
radius 150+-20AU seen at 45+-25deg inclination. More face-on orientations are
possible if the dust distribution includes two clumps similar to Vega; we show
how such a clumpy structure could arise from the migration over 25Myr of a
Neptune mass planet from 80-105AU. The inner 100AU of the system appears
relatively empty of sub-mm emitting dust, indicating that this region may have
been cleared by the formation of planets, but the disk emission spectrum shows
that IRAS detected an additional hot component with a characteristic
temperature of 370+-60K (implying a distance of 1-2AU). At 11.9um we found the
emission to be unresolved with no background sources which could be
contaminating the fluxes measured by IRAS. The age of this star is estimated to
be ~1Gyr. It is very unusual for such an old main sequence star to exhibit
significant mid-IR emission. The proximity of this source makes it a perfect
candidate for further study from optical to mm wavelengths to determine the
distribution of its dust.Comment: 22 pages, 4 figures. Scheduled for publication in ApJ 10 February
2005 issu
Phonons in graphene with point defects
The phonon density of states (DOS) of graphene with different types of point
defects (carbon isotopes, substitution atoms, vacancies) is considered. Using a
solvable model which is based on the harmonic approximation and the assumption
that the elastic forces act only between nearest neighboring ions we calculate
corrections to graphene DOS dependent on type and concentration of defects. In
particular the correction due to isotopic dimers is determined. It is shown
that a relatively small concentration of defects may lead to significant and
specific changes in the DOS, especially at low frequencies, near the Van Hove
points and in the vicinity of the K-points of the Brillouin zone. In some cases
defects generate one or several narrow gaps near the critical points of the
phonon DOS as well as resonance states in the Brillouin zone regular points.
All types of defects are characterized by the appearance of one or more
additional Van Hove peaks near the (Dirac) K points and their singular
contribution may be comparable with the effect of electron-phonon interaction.
Besides, for low frequencies and near the critical points the relative change
in density of states may be many times higher than the concentration of
defects.Comment: 19 pages, 7 figure
Charged Vacuum Bubble Stability
A type of scenario is considered where electrically charged vacuum bubbles,
formed from degenerate or nearly degenerate vacuua separated by a thin domain
wall, are cosmologically produced due to the breaking of a discrete symmetry,
with the bubble charge arising from fermions residing within the domain wall.
Stability issues associated with wall tension, fermion gas, and Coulombic
effects for such configurations are examined. The stability of a bubble depends
upon parameters such as the symmetry breaking scale and the fermion coupling. A
dominance of either the Fermi gas or the Coulomb contribution may be realized
under certain conditions, depending upon parameter values.Comment: 16 pages,revtex; accepted for publication in Phys.Rev.
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