5,139 research outputs found
PAR-3 defines a central subdomain of the cortical actin cap in mouse eggs
AbstractThe evolutionarily conserved partitioning defective (PAR) protein PAR-3 is pivotal for establishing and maintaining cell polarity. During mammalian oocyte maturation, the radially symmetric oocyte is transformed into a highly polarized metaphase II (MII)-arrested egg. We therefore examined several aspects of PAR-3 expression during oocyte maturation. We cloned two novel PAR-3 transcripts from an oocyte library that likely encode proteins of Mr = 73 K and 133 K that are phosphorylated during maturation. PAR-3, which is found throughout the GV-intact oocyte, becomes asymmetrically localized during meiosis. Following germinal vesicle breakdown, PAR-3 surrounds the condensing chromosomes and associates with the meiotic spindles. Prior to emission of the first and second polar bodies, PAR-3 is located within a central subdomain of the polarized actin cap, which overlies the spindle. This cortical PAR-3 localization depends on intact microfilaments. These results suggest a role for PAR-3 in establishing asymmetry in the egg and in defining the future site of polar body emission
Quantum Conductance Oscillations in Metal/Molecule/Metal Switches at Room Temperature
Conductance switching has been reported in many molecular junction devices,
but in most cases has not been convincingly explained. We investigate
conductance switching in Pt/stearic acid monolayer/Ti devices using
pressure-modulated conductance microscopy. For devices with conductance G>>G_Q
or G<<G_Q, where GQ=2e^2/h is the conductance quantum, pressure-induced
conductance peaks <30 nm in diameter are observed, indicating the formation of
nanoscale conducting pathways between the electrodes. For devices with G~ 1- 2
G_Q, in addition to conductance peaks we also observed conductance dips and
oscillations in response to localized pressure. These results can be modeled by
considering interfering electron waves along a quantum conductance channel
between two partially transmitting electrode surfaces. Our findings underscore
the possible use of these devices as atomic-scale switches
Two Large HI Shells in the Outer Galaxy near l=279 degrees
As part of a survey of HI 21-cm emission in the Southern Milky Way, we have
detected two large shells in the interstellar neutral hydrogen near l=279 deg.
The center velocities are +36 and +59 km/s, which puts the shells at kinematic
distances of 7 and 10 kpc. The larger shell is about 610 pc in diameter and
very empty, with density contrast of at least 15 between the middle and the
shell walls. It has expansion velocity of about 20 km/s and swept up mass of
several million solar masses. The energy indicated by the expansion may be as
high as 2.4 X 10^53 ergs. We estimate its age to be 15 to 20 million years. The
smaller shell has diameter of about 400 pc, expansion velocity about 10 km/s
and swept up mass of about 10^6 solar masses.
Morphologically both regions appear to be shells, with high density regions
mostly surrounding the voids, although the first appears to have channels of
low density which connect with the halo above and below the HI layer. They lie
on the edge of the Carina arm, which suggests that they may be expanding
horizontally into the interarm region as well as vertically out of the disk. If
this interpretation is correct, this is the first detection of an HI chimney
which has blown out of both sides of the disk.Comment: 21 pages, 14 jpeg figures, accepted for publication in A
The Neuroscience Information Framework: A Data and Knowledge Environment for Neuroscience
With support from the Institutes and Centers forming the NIH Blueprint for Neuroscience Research, we have designed and implemented a new initiative for integrating access to and use of Web-based neuroscience resources: the Neuroscience Information Framework. The Framework arises from the expressed need of the neuroscience community for neuroinformatic tools and resources to aid scientific inquiry, builds upon prior development of neuroinformatics by the Human Brain Project and others, and directly derives from the Society for Neuroscienceās Neuroscience Database Gateway. Partnered with the Society, its Neuroinformatics Committee, and volunteer consultant-collaborators, our multi-site consortium has developed: (1) a comprehensive, dynamic, inventory of Web-accessible neuroscience resources, (2) an extended and integrated terminology describing resources and contents, and (3) a framework accepting and aiding concept-based queries. Evolving instantiations of the Framework may be viewed at http://nif.nih.gov, http://neurogateway.org, and other sites as they come on line
A simple, low-cost conductive composite material for 3D printing of electronic sensors
3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (ārapid prototypingā) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ācarbomorphā and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes
The impact of brain-derived neurotrophic factor Val66Met polymorphism on cognition and functional brain networks in patients with intractable partial epilepsy
INTRODUCTION: Medial temporal lobe epilepsy (mTLE) is the most common refractory focal epilepsy in adults. Around 30%-40% of patients have prominent memory impairment and experience significant postoperative memory and language decline after surgical treatment. BDNF Val66Met polymorphism has also been associated with cognition and variability in structural and functional hippocampal indices in healthy controls and some patient groups. AIMS: We examined whether BDNF Val66Met variation was associated with cognitive impairment in mTLE. METHODS: In this study, we investigated the association of Val66Met polymorphism with cognitive performance (nĀ =Ā 276), postoperative cognitive change (nĀ =Ā 126) and fMRI activation patterns during memory encoding and language paradigms in 2 groups of patients with mTLE (nĀ =Ā 37 and 34). RESULTS: mTLE patients carrying the Met allele performed more poorly on memory tasks and showed reduced medial temporal lobe activation and reduced task-related deactivations within the default mode networks in both the fMRI memory and language tasks than Val/Val patients. CONCLUSIONS: Although cognitive impairment in epilepsy is the result of a complex interaction of factors, our results suggest a role of genetic factors on cognitive impairment in mTLE
Increased risk of HPV-associated genital cancers in men and women as a consequence of pre-invasive disease
To assess the excess risk of HPVāassociated cancer (HPVaC) in two atārisk groups ā women with a previous diagnosis of high grade cervical intraepithelial neoplasia (CIN3) and both men and women treated for nonācervical preāinvasive anoāgenital disease. All CIN3 cases diagnosed in 1989ā2015 in Scotland were extracted from the Scottish cancer registry (SMR06). All cases of preāinvasive penile, anal, vulval, and vaginal disease diagnosed in 1990ā2015 were identified within the NHS pathology databases in the two largest NHS health boards in Scotland. Both were linked to SMR06 to extract subsequent incidence of HPVaC following the diagnosis of CIN3 or preāinvasive disease. Standardised incidence ratios were calculated for the risk of acquiring HPVaC for the two atārisk groups compared with the general Scottish population. Among 69714 females in Scotland diagnosed with CIN3 (890360.9 personāyears), 179 developed nonācervical HPVaC. CIN3 cases were at 3.2āfold (95% CI: 2.7 to 3.7) increased risk of developing nonācervical HPVaC, compared to the general female population. Among 1235 patients diagnosed with nonācervical preāinvasive disease (9667.4 personāyears), 47 developed HPVaC. Individuals with nonācervical preāinvasive disease had a substantially increased risk of developing HPVaC ā 15.5āfold (95% CI: 11.1 to 21.1) increased risk for females and 28āfold (11.3 to 57.7) increased risk for males. We report a significant additional risk of HPVāassociated cancer in those have been diagnosed with preāinvasive HPVāassociated lesions including but not confined to the cervix. Uncovering the natural history of preāinvasive disease has potential for determining screening, prevention and treatment
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