18,517 research outputs found
Intelligent pressure-based typing biometrics system
The design and development of a real-time enhanced password security system, based on the analysis of habitual typing rhythms of individuals, is discussed in this paper. The paper examines the use of force exerted on the keyboard and time latency between keystrokes to create typing patterns for individual users. Pressure signals which are taken from the sensors underneath the keypad are extracted accordingly. These are then used to recognize authentic users and reject imposters. An experimental setup has been developed to capture the pressure signal information of the usersâ typing rhythm. Neuro-fuzzy system is employed as the classifier to measure the userâs typing pattern using the Adaptive Neural Fuzzy Inference System toolbox (ANFIS) in MATLAB
Draft Genome Sequence of a Community-Associated Methicillin- Resistant Panton-Valentine Leukocidin-Positive Staphylococcus aureus Sequence Type 30 Isolate from a Pediatric Patient with a Lung Infection in Brazil
The sequence of methicillin-resistant Staphylococcus aureus strain B6 (sequence type 30 [ST30], spa type t433, staphylococcal chromosomal cassette mec element [SCCmec] type IVc, Panton-Valentine leukocidin [PVL] positive), isolated from a pediatric patient with a lung infection in NiterĂłi, Rio de Janeiro, Brazil, is described here. The draft genome sequence includes a 2.8-Mb chromosome, accompanied by a 20-kb plasmid containing blaZ and two small cryptic plasmids
UBR2 of the N-end rule pathway is required for chromosome stability via histone ubiquitylation in spermatocytes and somatic cells
The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells. © 2012 Kwon et al
Identification and characterization of an inhibitory fibroblast growth factor receptor 2 (FGFR2) molecule, up-regulated in an Apert Syndrome mouse model
AS (Apert syndrome) is a congenital disease composed of skeletal, visceral and neural abnormalities, caused by dominant-acting mutations in FGFR2 [FGF (fibroblast growth factor) receptor 2]. Multiple FGFR2 splice variants are generated through alternative splicing, including PTC (premature termination codon)-containing transcripts that are normally eliminated via the NMD (nonsense-mediated decay) pathway. We have discovered that a soluble truncated FGFR2 molecule encoded by a PTC-containing transcript is up-regulated and persists in tissues of an AS mouse model. We have termed this IIIaâTM as it arises from aberrant splicing of FGFR2 exon 7 (IIIa) into exon 10 [TM (transmembrane domain)]. IIIaâTM is glycosylated and can modulate the binding of FGF1 to FGFR2 molecules in BIAcore-binding assays. We also show that IIIaâTM can negatively regulate FGF signalling in vitro and in vivo. AS phenotypes are thought to result from gain-of-FGFR2 signalling, but our findings suggest that IIIaâTM can contribute to these through a loss-of-FGFR2 function mechanism. Moreover, our findings raise the interesting possibility that FGFR2 signalling may be a regulator of the NMD pathway
Drosophila modifier screens to identify novel neuropsychiatric drugs including aminergic agents for the possible treatment of Parkinson's disease and depression.
Small molecules that increase the presynaptic function of aminergic cells may provide neuroprotection in Parkinson's disease (PD) as well as treatments for attention deficit hyperactivity disorder (ADHD) and depression. Model genetic organisms such as Drosophila melanogaster may enhance the detection of new drugs via modifier or 'enhancer/suppressor' screens, but this technique has not been applied to processes relevant to psychiatry. To identify new aminergic drugs in vivo, we used a mutation in the Drosophila vesicular monoamine transporter (dVMAT) as a sensitized genetic background and performed a suppressor screen. We fed dVMAT mutant larvae ⌠1000 known drugs and quantitated rescue (suppression) of an amine-dependent locomotor deficit in the larva. To determine which drugs might specifically potentiate neurotransmitter release, we performed an additional secondary screen for drugs that require presynaptic amine storage to rescue larval locomotion. Using additional larval locomotion and adult fertility assays, we validated that at least one compound previously used clinically as an antineoplastic agent potentiates the presynaptic function of aminergic circuits. We suggest that structurally similar agents might be used to development treatments for PD, depression and ADHD, and that modifier screens in Drosophila provide a new strategy to screen for neuropsychiatric drugs. More generally, our findings demonstrate the power of physiologically based screens for identifying bioactive agents for select neurotransmitter systems
Quasi-Simultaneous Two Band Optical Micro-Variability of Luminous Radio-Quiet QSOs
We report the first results of quasi-simultaneous two passband optical
monitoring of six quasi-stellar objects to search for micro-variability. We
carried out photometric monitoring of these sources in an alternating sequence
of R and V passbands, for five radio-quiet quasi-stellar objects (RQQSOs),
0748+291, 0824+098, 0832+251, 1101+319, 1225+317 and one radio-loud
quasi-stellar object (RLQSO), 1410+429. No micro-variability was detected in
any of the RQQSOs, but convincing micro-variability was detected in the RLQSO
on two successive nights it was observed. Using the compiled data of optical
micro-variability of RQQSOs till date, we got the duty cycle for
micro-variability in RQQSOs is 10%. The present investigation indicates
that micro-variability is not a persistent property of RQQSOs but an occasional
incident.Comment: 22 pages, 3 tables, 6 figures; Accepted for publication to New
Astronom
A confluence of cultures: advance care planning in long-term care settings
Context: While policies may promote Advance Care Planning (ACP) discussions in long-term care (LTC) settings, practices often result in outcomes different from residentsâ wishes. We attribute this to a confluence of cultures: healthcare; LTC settings; mainstream societal; and individualsâ ethno-cultures. This research explores these cultures as reflected in focus group discussions conducted with residents and family-of-residents in two LTC homes: one exclusively Chinese (EC); one multicultural (MC). Method: Fourteen residents and 13 family members participated in the four focus groups. Discussions were audio-recorded, transcribed, and themes were extracted and compared. Results: Four themes characterized residentsâ discussions: 1-Variations in Range/Type of ACP Discussions/Actions; 2-Care of Family; 3-Reliance on Staff; and 4-Quality-of-Life at End-of-Life. Exclusively Chinese residents expressed reluctance to speak about ACP, were more likely to state âfamily would handle it,â less likely to call upon staff, and more acquiescent concerning death. Multicultural residents were more likely to pejoratively mention pull or absence of family and reliance upon staff; also, wanting personal awareness and control at end-of-life. Family themes were 1-Timing/Focus of ACP Discussions, 2-Communication with Family, 3-Care Home and Staff Influences, and 4-Cultural and Religious Issues. Exclusively Chinese families spoke of need to involve family in ACP discussions inclusive of residents and of Chinese cultural influences on ACP. Multicultural families reported being âtaken by surpriseâ and feeling âoverwhelmedâ by requests to engage in ACP and document completion on behalf of residents. Conclusion: Findings provide evidence of multiple cultural influences on ACP in LTC but existing institutional policies and practices offer little direction and support on how to balance/prioritize them. Our analyses may provide a starting point
Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements
The thermal conductivity k of the iron-arsenide superconductor LiFeAs (Tc ~
18K) was measured in single crystals at temperatures down to T~50mK and in
magnetic fields up to H=17T, very close to the upper critical field Hc2~18T.
For both directions of the heat current, parallel and perpendicular to the
tetragonal c-axis, a negligible residual linear term k/T is found as T ->0,
revealing that there are no zero-energy quasiparticles in the superconducting
state. The increase in k with magnetic field is the same for both current
directions and it follows closely the dependence expected for an isotropic
superconducting gap. There is no evidence of multi-band character, whereby the
gap would be different on different Fermi-surface sheets. These findings show
that the superconducting gap in LiFeAs is isotropic in 3D, without nodes or
deep minima anywhere on the Fermi surface. Comparison with other iron-pnictide
superconductors suggests that a nodeless isotropic gap is a common feature at
optimal doping (maximal Tc).Comment: 4 pages, 3 figure
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