1,261 research outputs found
Crystallographic structure of ultrathin Fe films on Cu(100)
We report bcc-like crystal structures in 2-4 ML Fe films grown on fcc Cu(100)
using scanning tunneling microscopy. The local bcc structure provides a
straightforward explanation for their frequently reported outstanding magnetic
properties, i.e., ferromagnetic ordering in all layers with a Curie temperature
above 300 K. The non-pseudomorphic structure, which becomes pseudomorphic above
4 ML film thickness is unexpected in terms of conventional rules of thin film
growth and stresses the importance of finite thickness effects in ferromagnetic
ultrathin films.Comment: 4 pages, 3 figures, RevTeX/LaTeX2.0
hnRNP A2, a Potential ssDNA/RNA Molecular Adapter at the Telomere
The heterogeneous nuclear ribonucleoprotein (hnRNP) A2 is a multi-tasking protein that acts in the cytoplasm and nucleus. We have explored the possibility that this protein is associated with telomeres and participates in their maintenance. Rat brain hnRNP A2 was shown to have two nucleic acid binding sites. In the presence of heparin one site binds single-stranded oligodeoxyribonucleotides irrespective of sequence but not the corresponding oligoribonucleotides. Both the hnRNP A2-binding cis-acting element for the cytoplasmic RNA trafficking element, A2RE, and the ssDNA telomere repeat match a consensus sequence for binding to a second sequence-specific site identified by mutational analysis. hnRNP A2 protected the telomeric repeat sequence, but not the complementary sequence, against DNase digestion: the glycine-rich domain was found to be necessary, but not sufficient, for protection. The N-terminal RRM (RNA recognition motif) and tandem RRMs of hnRNP A2 also bind the single-stranded, template-containing segment of telomerase RNA. hnRNP A2 colocalizes with telomeric chromatin in the subset of PML bodies that are a hallmark of ALT cells, reinforcing the evidence for hnRNPs having a role in telomere maintenance. Our results support a model in which hnRNP A2 acts as a molecular adapter between singlestranded telomeric repeats, or telomerase RNA, and another segment of ssDNA.Full Tex
miR-132/212 knockout mice reveal roles for these miRNAs in regulating cortical synaptic transmission and plasticity
miR-132 and miR-212 are two closely related miRNAs encoded in the same intron of a small non-coding gene, which have been suggested to play roles in both immune and neuronal function. We describe here the generation and initial characterisation of a miR-132/212 double knockout mouse. These mice were viable and fertile with no overt adverse phenotype. Analysis of innate immune responses, including TLR-induced cytokine production and IFNβ induction in response to viral infection of primary fibroblasts did not reveal any phenotype in the knockouts. In contrast, the loss of miR-132 and miR-212, while not overtly affecting neuronal morphology, did affect synaptic function. In both hippocampal and neocortical slices miR-132/212 knockout reduced basal synaptic transmission, without affecting paired-pulse facilitation. Hippocampal long-term potentiation (LTP) induced by tetanic stimulation was not affected by miR-132/212 deletion, whilst theta burst LTP was enhanced. In contrast, neocortical theta burst-induced LTP was inhibited by loss of miR-132/212. Together these results indicate that miR-132 and/or miR-212 play a significant role in synaptic function, possibly by regulating the number of postsynaptic AMPA receptors under basal conditions and during activity-dependent synaptic plasticity
"Cold Melting" of Invar Alloys
An anomalously strong volume magnetostriction in Invars may lead to a
situation when at low temperatures the dislocation free energy becomes negative
and a multiple generation of dislocations becomes possible. This generation
induces a first order phase transition from the FCC crystalline to an amorphous
state, and may be called "cold melting". The possibility of the cold melting in
Invars is connected with the fact that the exchange energy contribution into
the dislocation self energy in Invars is strongly enhanced, as compared to
conventional ferromagnetics, due to anomalously strong volume magnetostriction.
The possible candidate, where this effect can be observed, is a FePt disordered
Invar alloy in which the volume magnetostriction is especially large
Experimental Sonic Boom Measurements on a Mach 1.6 Cruise Low-Boom Configuration
A wind tunnel test has been conducted by Gulfstream Aerospace Corporation (GAC) to measure the sonic boom pressure signature of a low boom Mach 1.6 cruise business jet in the Langley Unitary Plan Wind Tunnel at Mach numbers 1.60 and 1.80. Through a cooperative agreement between GAC and the National Aeronautics and Space Administration (NASA), GAC provided NASA access to some of the experimental data and NASA is publishing these data for the sonic boom research community. On-track and off-track near field sonic boom pressure signatures were acquired at three separation distances (0.5, 1.2, and 1.7 reference body lengths) and three angles of attack (-0.26deg, 0.26deg, and 0.68deg). The model was blade mounted to minimize the sting effects on the sonic boom signatures. Although no extensive data analysis is provided, selected data are plotted to illustrate salient features of the data. All of the experimental sonic boom pressure data are tabulated. Schlieren images of the configuration are also included
An integrated leadership model for leading Education for Sustainability in Higher Education and the vital role of students as change agents
Процесс анализа угроз, влияющих на экономическую устойчивость предприятия
На основании проведенного исследования были выявлены факторы возникновения угроз, их группировка по степени воздействию на экономическую устойчивость предприятий и рассмотрена формализация процесса анализа угроз экономической устойчивости предприятий. В условиях рыночной экономики невозможно управлять предприятием без учета влияния угроз, а для эффективного управления важно не только знать об их присутствии, а и правильно идентифицировать конкретную угрозу.На підставі проведеного дослідження були виявлені чинники виникнення загроз, їх угруповання по степені впливу на економічну стійкість підприємств і розглянута формалізація процесу аналізу загроз економічної стійкості підприємств. В умовах ринкової економіки неможливо керувати підприємством без вивчення впливу загроз, а для ефективного керування важливо не тільки знати про їх присутність, а і правильно ідентифікувати конкретну загрозу.On the basis of the conducted research the factors of origin of threats were exposed, their gourmet on a degree to influence on economic stability of enterprises and formalization of process of analysis of threats of economic stability of enterprises is considered. In the conditions of market economy it is impossible to manage an enterprise without taking into account influencing of threats, and for the effective management it is important not only to know about their presence, and to identify the concrete threat correctly
Metal alloys, matrix inclusions and manufacturing techniques of Moinhos de Golas collection (North Portugal): a study by micro-EDXRF, SEM–EDS, optical microscopy and X-ray radiography
"Article:820"A collection of 35 metallic artefacts comprising
various typologies, some of which can be attributed to the
Bronze Age and others to later periods, were studied to
provide detailed information on elemental composition,
manufacturing techniques and preservation state. Elemental
analysis by micro-EDXRF and SEM–EDS was performed
to investigate the use of different alloys and to
study the presence of microstructural heterogeneities, as
inclusions. X-ray radiography, optical microscopy and
SEM–EDS were used to investigate manufacturing techniques
and degradation features. Results showed that most
of the artefacts were produced in a binary bronze alloy
(Cu–Sn) with 10–15 wt% Sn and a low concentration of
impurities. Other artefacts were produced in copper or in
brass, the latest with varying contents of Zn, Sn and Pb. A
variety of inclusions in the metal matrices were also found,
some related to specific types of alloys, as (Cu–Ni)S2 in
coppers, or ZnS in brasses. Microstructural observations
revealed that the majority of the artefacts were subjected to
cycles of thermomechanical processing after casting, being
evident that among some artefacts different parts were
subjected to distinct treatments. The radiographic images
revealed structural heterogeneities related to local corrosion
processes and fissures that seem to have developed in
wear-tension zones, as in the handle of some daggers.
Radiographic images were also useful to detect the use of
different materials in one particular brass artefact, revealing
the presence of a possible Cu–Sn solder.This work was funded by FEDER funds through
the COMPETE 2020 Programme and National Funds through FCT—
Fundação para a Ciência e a Tecnologia under the project UID/CTM/
50025/2013 to CENIMAT/I3N. C2
TN/IST authors gratefully
acknowledge the FCT support through the UID/Multi/04349/2013
project. EF acknowledges FCT for the grant SFRH/BPD/97360/2013.
JF acknowledge FCT for the grant SFRH/BD/65143/2009. Part of this
project has been done in the framework of the FCT project ENARDAS
(PTDC/HISARQ/112983/2009).info:eu-repo/semantics/publishedVersio
Loureirin B, an essential component of Sanguis Draxonis, inhibits Kv1.3 channel and suppresses cytokine release from Jurkat T cells
Sanguis draxonis (SD), also known as “Dragon’s Blood”, is a traditional herb medicine that has been used to treat a variety of complications with unknown mechanisms. Recent studies show that SD displays immunosuppressive activities and improves symptoms of type I diabetes in animal models. However, the mechanisms underlying SD’s immunosuppressive actions are not completely understood. The voltage-gated Kv1.3 channel plays a critical role in the pathogenesis of autoimmune diseases by regulating the functions of both T cells and B cells. Here we investigated the effect of SD and one of its active components loureirin B (LrB) on Kv1.3. Both SD and LrB inhibited Kv1.3-mediated currents, produced a membrane depolarization, and reduced Ca(2+) influx in Jurkat T cells. In addition, application of LrB inhibited phytohemagglutinin (PHA)-induced IL-2 release from activated Jurkat T cells. Furthermore, point mutations in the selective filter region significantly reduced the inhibitory effect of LrB on Kv1.3. The results of these experiments provide evidence that LrB is a channel blocker of Kv1.3 by interacting with amino acid residues in its selective filter region. Direct inhibition of Kv1.3 in T cells by SD and LrB might be the cellular and molecular basis of SD-mediated immunosuppression
Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications
BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients.
OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs.
DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification.
PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries.
MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes.
RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure.
CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome
- …
