282 research outputs found
Temperature dependent asymmetry of the nonlocal spin-injection resistance: evidence for spin non-conserving interface scattering
We report nonlocal spin injection and detection experiments on mesoscopic
Co-Al2O3-Cu spin valves. We have observed a temperature dependent asymmetry in
the nonlocal resistance between parallel and antiparallel configurations of the
magnetic injector and detector. This strongly supports the existence of a
nonequilibrium resistance that depends on the relative orientation of the
detector magnetization and the nonequilibrium magnetization in the normal metal
providing evidence for increasing interface spin scattering with temperature.Comment: 5 pages, 4 figures, accepted for publication in PRL, minor
corrections (affiliation, acknowledgements, typo
Udar mĂłzgu u mĆodej kobiety ze Ćluzakiem serca â opis przypadku
Choroby naczyĆ mĂłzgowych, w tym udar mĂłzgu, stanowiÄ
trzeciÄ
pod wzglÄdem czÄstoĆci przyczynÄ zgonĂłw w Polsce. OkoĆo80% udarĂłw ma charakter niedokrwienny. JednÄ
z przyczyn udarumoĆŒe byÄ materiaĆ zatorowy pochodzÄ
cy z lewego przedsionkaserca. W leczeniu udaru rekomenduje siÄ zastosowanie doĆŒylnejtrombolizy z uĆŒyciem rekombinowanego tkankowego aktywatoraplazminogenu. W pracy przedstawiono przypadek 38-letniej kobietyz niedokrwiennym udarem mĂłzgu spowodowanym zatorowoĆciÄ
w przebiegu rzadkiego nowotworu serca â Ćluzaka.W takim przypadku szybko podjÄte leczenie moĆŒe uchroniÄ pacjentĂłwprzed niepeĆnosprawnoĆciÄ
i zgonem
Comparison of Clonidine and Midazolam Premedication Before Endoscopic Sinus Surgery: Results of Clinical Trial
ObjectivesPremedication with clonidine has been found to reduce the bleeding during endoscopic sinus surgery (ESS), therefore lowering the risk of surgical complications. Premedication is an essential part of pre-surgical care and can potentially affect magnitude of systemic stress response to a surgical procedure. The aim of this study was to compare the efficacy of premedication with clonidine and midazolam in patients undergoing sinus surgery.MethodsForty-four patients undergoing ESS for chronic sinusitis and polyp removal were enrolled and randomly assigned to receive either oral clonidine or midazolam as a premedication before receiving propofol/remifentanil total intravenous anesthesia. The effect of this premedication choice on anesthetic requirements, intraoperative hemodynamic profile, preoperative anxiety and sedation as well as postoperative pain and shivering were examined in each premedication group.ResultsTotal intraoperative remifentanil requirement was lower in the clonidine group as compared to the midazolam group 503.2±147.0 ”g vs. 784.5±283.8 ”g, respectively (P<0.001). There was no difference between groups in required induction dose of propofol, level of preoperative anxiety, level of sedation and postoperative shivering. Intraoperative systemic blood pressure and heart rate response had a more favorable profile in patients premedicated with clonidine. Postoperative pain assessed by visual analogue scale for pain was lower in the clonidine group compared with to the midazolam premedication group.ConclusionPremedication with clonidine provides better attenuation of hemodynamic response and reduction of intraoperative remifentanil requirements in patients undergoing ESS. Postoperative pain seems to be better controlled after clonidine premedication as well
The effects of aging on neuropil structure in mouse somatosensory cortex-A 3D electron microscopy analysis of layer 1
This study has used dense reconstructions from serial EM images to compare the neuropil ultrastructure and connectivity of aged and adult mice. The analysis used models of axons, dendrites, and their synaptic connections, reconstructed from volumes of neuropil imaged in layer 1 of the somatosensory cortex. This shows the changes to neuropil structure that accompany a general loss of synapses in a well-defined brain region. The loss of excitatory synapses was balanced by an increase in their size such that the total amount of synaptic surface, per unit length of axon, and per unit volume of neuropil, stayed the same. There was also a greater reduction of inhibitory synapses than excitatory, particularly those found on dendritic spines, resulting in an increase in the excitatory/inhibitory balance. The close correlations, that exist in young and adult neurons, between spine volume, bouton volume, synaptic size, and docked vesicle numbers are all preserved during aging. These comparisons display features that indicate a reduced plasticity of cortical circuits, with fewer, more transient, connections, but nevertheless an enhancement of the remaining connectivity that compensates for a generalized synapse loss
Przyczyny dyskwalifikacji pacjentĂłw z chorobÄ Parkinsona z leczenia za pomocÄ gĆÄbokiej stymulacji mĂłzgu
Choroba Parkinsona jest schorzeniem zwyrodnieniowym oĆrodkowego ukĆadu nerwowego, w ktĂłrym dochodzi do zmniejszenia aktywnoĆci ukĆadu dopaminergicznego, z towarzyszÄ
cymi zaburzeniami czynnoĆci wielu innych ukĆadĂłw neuroprzekaĆșnikowych w jÄ
drach podstawy i ich poĆÄ
czeniach. Choroba ma charakter postÄpujÄ
cy i mimo stosowanego leczenia po pewnym czasie prowadzi do znacznego inwalidztwa. Po wyczerpaniu moĆŒliwoĆci modyfikacji leczenia farmakologicznego u niektĂłrych chorych moĆŒna rozwaĆŒyÄ leczenie neurochirurgiczne, ktĂłrego celem jest poprawa jakoĆci ich ĆŒycia.
Celem pracy byĆa analiza najczÄstszych przyczyn dyskwalifikacji z leczenia neurochirurgicznego za pomocÄ
gĆÄbokiej stymulacji mĂłzgu pacjentĂłw z chorobÄ
Parkinsona w Klinice Neurologicznej 10. Wojskowego Szpitala Klinicznego w Bydgoszczy. AnalizÄ
objÄto 54 osoby z chorobÄ
Parkinsona, w tym 38 mÄĆŒczyzn i 16 kobiet, w wieku 48â82 lat, badanych w latach 2012â2014. Kryteriami dyskwalifikacji z leczenia neurochirurgicznego byĆy: wiek powyĆŒej 70 lat, czas trwania choroby krĂłtszy niĆŒ 5 lat oraz ponad 15 lat, niewystarczajÄ
ca odpowiedĆș na lewodopÄ (poprawa stanu ruchowego w fazie on w porĂłwnaniu z fazÄ
off w III cz. UPDRS < 33%), poprawa stanu klinicznego po modyfikacji leczenia farmakologicznego, stwierdzenie otÄpienia lub innych zaburzeĆ psychicznych, w tym depresyjnych, a takĆŒe istotnych zmian naczyniopochodnych w strukturach podkorowych mĂłzgu oraz zanik korowy mĂłzgowia w badaniu rezonansu magnetycznego. NajczÄstszÄ
przyczynÄ
braku kwalifikacji do zabiegu gĆÄbokiej stymulacji mĂłzgu byĆy istotne zmiany naczyniopochodne w mĂłzgowiu, co stwierdzono u 9 kobiet (56,2%) i 15 mÄĆŒczyzn (39,4%). DrugÄ
najczÄstszÄ
przyczynÄ
w obu populacjach byĆy nasilone zaburzenia depresyjne â u 6 kobiet (37,5%) i 14 mÄĆŒczyzn (36,8%). Do leczenia operacyjnego chorych kwalifikowaĆ lekarz prowadzÄ
cy; decyzja ta nie wynikaĆa z sugestii chorego ani jego rodziny
The Schistosoma mansoni tegumental-allergen-like (TAL) protein family: influence of developmental expression on human IgE responses
BACKGROUND: A human IgE response to Sm22.6 (a dominant IgE target in Schistosoma mansoni) is associated with the development of partial immunity. Located inside the tegument, the molecule belongs to a family of proteins from parasitic platyhelminths, the Tegument-Allergen-Like proteins (TALs). In addition to containing dynein-light-chain domains, these TALs also contain EF-hand domains similar to those found in numerous EF-hand allergens. METHODOLOGY/PRINCIPAL FINDINGS: S. mansoni genome searches revealed 13 members (SmTAL1-13) within the species. Recent microarray data demonstrated they have a wide range of life-cycle transcriptional profiles. We expressed SmTAL1 (Sm22.6), SmTAL2, 3, 4, 5 and 13 as recombinant proteins and measured IgE and IgG4 in 200 infected males (7â60 years) from a schistosomiasis endemic region in Uganda. For SmTAL1 and 3 (transcribed in schistosomula through adult-worms and adult-worms, respectively) and SmTAL5 (transcribed in cercariae through adult-worms), detectable IgE responses were rare in 7â9 year olds, but increased with age. At all ages, IgE to SmTAL2 (expressed constitutively), was rare while anti-SmTAL2 IgG4 was common. Levels of IgE and IgG4 to SmTAL4 and 13 (transcribed predominantly in the cercariae/skin stage) were all low. CONCLUSIONS: We have not measured SmTAL protein abundance or exposure in live parasites, but the antibody data suggests to us that, in endemic areas, there is priming and boosting of IgE to adult-worm SmTALs by occasional death of long-lived worms, desensitization to egg SmTALs through continuous exposure to dying eggs and low immunogenicity of larval SmTALs due to immunosuppression in the skin by the parasite. Of these, it is the gradual increase in IgE to the worm antigens that parallels age-dependent immunity seen in endemic areas
Induction of human regulatory innate lymphoid cells from group 2 innate lymphoid cells by retinoic acid
BACKGROUND: Group 2 innate lymphoid cells (ILC2s) play critical roles in induction and exacerbation of allergic airway inflammation. Thus, clarification of the mechanisms that underlie the regulation of ILC2 activation has received significant attention. Although ILCs are divided into three major subsets that mirror helper effector T-cell subsets, counterpart subsets of regulatory T (Treg) cells have not been well characterized.
OBJECTIVE: We sought to determine the factors that induce regulatory ILCs (ILCregs).
METHODS: IL-10+ ILCregs induced from ILC2s by retinoic acid (RA) were analyzed using RNA-sequencing and flow cytometry. ILCregs were evaluated in human nasal tissues from healthy individuals and patients with chronic rhinosinusitis with nasal polyp (CRSwNP), and in lung tissues from house dust mite (HDM)- or saline-treated mice.
RESULTS: RA induced IL-10 secretion by human ILC2s, but not type-2 cytokines. IL-10+ ILCregs, converted from ILC2s by RA stimulation, expressed a Treg-like signature with the expression of IL-10, CTLA-4 and CD25, with down regulated effector type 2-related markers such as CRTH-2 and ST2, and suppressed activation of CD4+ T cells and ILC2s. ILCregs were rarely detected in human nasal tissue from healthy individuals or lung tissues from saline-treated mice, but were increased in nasal tissues from patients with CRSwNP and in lung tissues from HDM-treated mice. Enzymes for RA synthesis were up-regulated in airway epithelial cells during type-2 inflammation in vivo and by IL-13 in vitro.
CONCLUSION: We have identified a unique immune regulatory and anti-inflammatory pathway by which RA converts ILC2s to ILCregs. Interactions between airway epithelial cells and ILC2s play an important roles in the generation of ILCregs
Survey of highly non-Keplerian orbits with low-thrust propulsion
Celestial mechanics has traditionally been concerned with orbital motion under the action of a conservative gravitational potential. In particular, the inverse square gravitational force due to the potential of a uniform, spherical mass leads to a family of conic section orbits, as determined by Isaac Newton, who showed that Keplerâs laws were derivable from his theory of gravitation. While orbital motion under the action of a conservative gravitational potential leads to an array of problems with often complex and interesting solutions, the addition of non-conservative forces offers new avenues of investigation. In particular, non-conservative forces lead to a rich diversity of problems associated with the existence, stability and control of families of highly non-Keplerian orbits generated by a gravitational potential and a non-conservative force. Highly non-Keplerian orbits can potentially have a broad range of practical applications across a number of different disciplines. This review aims to summarize the combined wealth of literature concerned with the dynamics, stability and control of highly non-Keplerian orbits for various low thrust propulsion devices, and to demonstrate some of these potential applications
Extension of Earth-Moon libration point orbits with solar sail propulsion
This paper presents families of libration point orbits in the Earth-Moon system that originate from complementing the classical circular restricted three-body problem with a solar sail. Through the use of a differential correction scheme in combination with a continuation on the solar sail induced acceleration, families of Lyapunov, halo, vertical Lyapunov, Earth-centred, and distant retrograde orbits are created. As the solar sail circular restricted three-body problem is non-autonomous, a constraint defined within the differential correction scheme ensures that all orbits are periodic with the Sunâs motion around the Earth-Moon system. The continuation method then starts from a classical libration point orbit with a suitable period and increases the solar sail acceleration magnitude to obtain families of orbits that are parametrised by this acceleration. Furthermore, different solar sail steering laws are considered (both in-plane and out-of-plane, and either fixed in the synodic frame or fixed with respect to the direction of sunlight), adding to the wealth of families of solar sail enabled libration point orbits presented. Finally, the linear stability properties of the generated orbits are investigated to assess the need for active orbital control. It is shown that the solar sail induced acceleration can have a positive effect on the stability of some orbit families, especially those at the L2 point, but that it most often (further) destabilises the orbit. Active control will therefore be needed to ensure long-term survivability of these orbits
Solar Sail Propulsion: Enabling New Capabilities for Heliophysics
Solar sails can play a critical role in enabling solar and heliophysics missions. Solar sail technology within NASA is currently at 80% of TRL-6, suitable for an in-flight technology demonstration. It is conceivable that an initial demonstration could carry scientific payloads that, depending on the type of mission, are commensurate with the goals of the three study panels of the 2010 Heliophysics Survey. Follow-on solar sail missions, leveraging advances in solar sail technology to support Heliophysics Survey goals, would then be feasible. This white paper reports on a sampling of missions enabled by solar sails, the current state of the technology, and what funding is required to advance the current state of technology such that solar sails can enable these mission
- âŠ