755 research outputs found
Novel effects of strains in graphene and other two dimensional materials
The analysis of the electronic properties of strained or lattice deformed
graphene combines ideas from classical condensed matter physics, soft matter,
and geometrical aspects of quantum field theory (QFT) in curved spaces. Recent
theoretical and experimental work shows the influence of strains in many
properties of graphene not considered before, such as electronic transport,
spin-orbit coupling, the formation of Moir\'e patterns, optics, ... There is
also significant evidence of anharmonic effects, which can modify the
structural properties of graphene. These phenomena are not restricted to
graphene, and they are being intensively studied in other two dimensional
materials, such as the metallic dichalcogenides. We review here recent
developments related to the role of strains in the structural and electronic
properties of graphene and other two dimensional compounds.Comment: 75 pages, 15 figures, review articl
Design of Science Orbits About Planetary Satellites: Application to Europa
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76381/1/AIAA-19464-587.pd
Effects of caffeine supplementation on physical performance and mood dimensions in elite and trained-recreational athletes.
Background: Caffeine supplementation (CAFF) has an established ergogenic effect on physical performance and
the psychological response to exercise. However, few studies have compared the response to CAFF intake among
athletes of different competition level. This study compares the acute effects of CAFF on anaerobic performance,
mood and perceived effort in elite and moderately-trained recreational athletes.
Methods: Participants for this randomized, controlled, crossover study were 8 elite athletes (in the senior boxing
national team) and 10 trained-recreational athletes. Under two experimental conditions, CAFF supplementation
(6 mg/kg) or placebo (PLAC), the athletes completed a Wingate test. Subjective exertion during the test was
recorded as the rating of perceived exertion (RPE) both at the general level (RPEgeneral) and at the levels
muscular (RPEmuscular) and cardiorespiratory (RPEcardio). Before the Wingate test, participants completed the
questionnaires Profiles of Moods States (POMS) and Subjective Vitality Scale (SVS).
Results: In response to CAFF intake, improvements were noted in Wpeak (11.22 ± 0.65 vs 10.70 ± 0.84; p =
0.003; η2
p =0.44), Wavg (8.75 ± 0.55 vs 8.41 0.46; p = 0.001; η2
p =0.53) and time taken to reach Wpeak (7.56 ± 1.58
vs 9.11 ± 1.53; p < 0.001; η2
p =0.57) both in the elite and trained-recreational athletes. However, only the elite
athletes showed significant increases in tension (+ 325%), vigor (+ 31%) and SVS (+ 28%) scores after the
intake of CAFF compared to levels recorded under the condition PLAC (p < 0.05). Similarly, levels of vigor
after consuming CAFF were significantly higher in the elite than the trained-recreational athletes (+ 5.8%).
Conclusions: CAFF supplementation improved anaerobic performance in both the elite and recreational
athletes. However, the ergogenic effect of CAFF on several mood dimensions and subjective vitality was
greater in the elite athletes.post-print700 K
The search for gametic maturity markers in the gametogenic cycle of Crassostrea gigas (Thunberg, 1873)
One of the aims of bivalve culture is obtaining high quality broodstocks in hatcheries. Spawning feasibility depends on a suitable breeder's feeding, and can be artificially induced. Some external factors (environmental) and internal (neuroendocrinal) seem to contribute to gamete maturation. Crassostrea gigas (Thunberg, 1873) gametogenic cycle is characterised by long resting periods during which a high rate of degradation and cellular atresia has been observed. There are also remarkable differences between male and female protein profiles during gametogenic development. Our group has been searching for molecular indicators of the state of maturation, and the most suitable moment for spawning induction. One of our most promising results was the appearance of a membrane protein in females thought to be a signal receptor in oocyte maturation and spawning.El cultivo de bivalvos se ve limitado por la obtención de semilla de calidad en los criaderos. El éxito de las puestas depende de la alimentación adecuada de los reproductores, y pueden ser inducidas artificialmente mediante choque osmótico, térmico u otras técnicas. Algunos factores externos, como los ambientales, e internos, de carácter neuroendocrino, parecen contribuir a la maduración de los gametos. El ciclo gametogénico de Crassostrea gigas (Thunberg, 1873) se caracteriza por largos periodos de reposo gonadal, en los que se ha encontrado una tasa elevada de degradación y atresia celular. También se aprecian diferencias considerables entre hembras y machos en los perfiles proteínicos durante el desarrollo gametogénico. El presente trabajo está orientado a la búsqueda de marcadores del estado de madurez de los gametos como indicadores del momento más adecuado para inducir la puesta. Uno de los resultados obtenidos ha sido la visualización de una proteína de membrana en hembras, que se muestra en la fase de madurez de los ovocitos y en las puestas, que podría constituir uno de los macadores buscados.Instituto Español de Oceanografí
Strain-induced Evolution of Electronic Band Structures in a Twisted Graphene Bilayer
Here we study the evolution of local electronic properties of a twisted
graphene bilayer induced by a strain and a high curvature. The strain and
curvature strongly affect the local band structures of the twisted graphene
bilayer; the energy difference of the two low-energy van Hove singularities
decreases with increasing the lattice deformations and the states condensed
into well-defined pseudo-Landau levels, which mimic the quantization of massive
Dirac fermions in a magnetic field of about 100 T, along a graphene wrinkle.
The joint effect of strain and out-of-plane distortion in the graphene wrinkle
also results in a valley polarization with a significant gap, i.e., the
eight-fold degenerate Landau level at the charge neutrality point is splitted
into two four-fold degenerate quartets polarized on each layer. These results
suggest that strained graphene bilayer could be an ideal platform to realize
the high-temperature zero-field quantum valley Hall effect.Comment: 4 figure
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A three-dimensional numerical model of predevelopment conditions in the Death Valley regional ground-water flow system, Nevada and California
In the early 1990's, two numerical models of the Death Valley regional ground-water flow system were developed by the U.S. Department of Energy. In general, the two models were based on the same basic hydrogeologic data set. In 1998, the U.S. Department of Energy requested that the U.S. Geological Survey develop and maintain a ground-water flow model of the Death Valley region in support of U.S. Department of Energy programs at the Nevada Test Site. The purpose of developing this ''second-generation'' regional model was to enhance the knowledge and understanding of the ground-water flow system as new information and tools are developed. The U.S. Geological Survey also was encouraged by the U.S. Department of Energy to cooperate to the fullest extent with other Federal, State, and local entities in the region to take advantage of the benefits of their knowledge and expertise. The short-term objective of the Death Valley regional ground-water flow system project was to develop a steady-stat e representation of the predevelopment conditions of the ground-water flow system utilizing the two geologic interpretations used to develop the previous numerical models. The long-term objective of this project was to construct and calibrate a transient model that simulates the ground-water conditions of the study area over the historical record that utilizes a newly interpreted hydrogeologic conceptual model. This report describes the result of the predevelopment steady-state model construction and calibration
Intravenous Busulfan and Melphalan as a Conditioning Regimen for Autologous Stem Cell Transplantation in Patients with Newly Diagnosed Multiple Myeloma: A Matched Comparison to a Melphalan-Only Approach
AbstractMelphalan 200 mg/m2 (MEL200) is the standard conditioning regimen administered to newly diagnosed patients with multiple myeloma (MM) undergoing autologous stem cell transplantation (ASCT). Few alternatives have been explored in order to improve the antimyeloma activity of this conditioning. We compare i.v. busulfan (BU) 9.6 mg/kg and MEL 140 mg/m2 (MEL140) versus MEL200 mg/m2 as a conditioning regimen before ASCT for newly diagnosed patients with MM. For this purpose, 51 patients receiving i.v. BU plus MEL were compared to 102 patients receiving MEL200 mg/m2 in a 1:2 matched control analysis. Matching criteria included age, clinical stage at diagnosis, and response to induction therapy. No differences in the overall and complete response (CR) rates were observed after ASCT between both groups. After a median follow-up of 63 and 50 months in control and BU plus MEL groups, progression-free survival (PFS) was 24 and 33 months, respectively (P = .10). Most frequent toxicities included mucositis and febrile neutropenia in both groups. No case of sinusoidal obstruction syndrome was observed. Transplant-related mortality was 4% and 2% in BU plus MEL and control groups, respectively. ASCT conditioned with i.v. BU plus MEL may be considered an effective and well-tolerated alternative to a MEL-only approach as a conditioning regimen for patients with MM who are candidates for ASCT. (Clinicaltrials.gov identifier: NCT00560053 and NCT00804947.
Multi-band high resolution spectroscopy rules out the hot Jupiter BD+20 1790b - First data from the GIARPS Commissioning
Context. Stellar activity is currently challenging the detection of young
planets via the radial velocity (RV) technique. Aims. We attempt to
definitively discriminate the nature of the RV variations for the young active
K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent
results on the existence of a substellar companion. Methods. We compare VIS
data with high precision RVs in the near infrared (NIR) range by using the
GIANO - B and IGRINS spectrographs. In addition, we present for the first time
simultaneous VIS-NIR observations obtained with GIARPS (GIANO - B and HARPS -
N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV
amplitude does not change at different wavelengths, while stellar activity
induces wavelength-dependent RV variations, which are significantly reduced in
the NIR range with respect to the VIS. Results. The NIR radial velocity
measurements from GIANO - B and IGRINS show an average amplitude of about one
quarter with respect to previously published VIS data, as expected when the RV
jitter is due to stellar activity. Coeval multi-band photometry surprisingly
shows larger amplitudes in the NIR range, explainable with a mixture of cool
and hot spots in the same active region. Conclusions. In this work, the claimed
massive planet around BD+20 1790 is ruled out by our data. We exploited the
crucial role of multi- wavelength spectroscopy when observing young active
stars: thanks to facilities like GIARPS that provide simultaneous observations,
this method can reach its maximum potential.Comment: 12 pages, 7 figure
In vivo murine model of acquired resistance in myeloma reveals differential mechanisms for lenalidomide and pomalidomide in combination with dexamethasone
The development of resistance to therapy is unavoidable in the history of multiple myeloma patients. Therefore, the study of its characteristics and mechanisms is critical in the search for novel therapeutic approaches to overcome it. This effort is hampered by the absence of appropriate preclinical models, especially those mimicking acquired resistance. Here we present an in vivo model of acquired resistance based on the continuous treatment of mice bearing subcutaneous MM1S plasmacytomas. Xenografts acquired resistance to two generations of immunomodulatory drugs (IMiDs; lenalidomide and pomalidomide) in combination with dexamethasone, that was reversible after a wash-out period. Furthermore, lenalidomide-dexamethasone (LD) or pomalidomide-dexamethasone (PD) did not display cross-resistance, which could be due to the differential requirements of the key target Cereblon and its substrates Aiolos and Ikaros observed in cells resistant to each combination. Differential gene expression profiles of LD and PD could also explain the absence of cross-resistance. Onset of resistance to both combinations was accompanied by upregulation of the mitogen-activated protein kinaseextracellular signal-regulated kinase (ERK) kinase (MEK)ERK pathway and addition of selumetinib, a small-molecule MEK inhibitor, could resensitize resistant cells. Our results provide insights into the mechanisms of acquired resistance to LD and PD combinations and offer possible therapeutic approaches to addressing IMiD resistance in the clinic.Peer Reviewe
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