726 research outputs found
First detection of the 448 GHz H2O transition in space
We present the first detection of the ortho-H2O 4_23-3_30 transition at 448
GHz in space. We observed this transition in the local (z = 0.010) luminous
infrared (IR) galaxy ESO 320-G030 (IRAS F11506-3851) using the Atacama Large
Millimeter/submillimeter Array (ALMA). The water 4_23-3_30 emission, which
originates in the highly obscured nucleus of this galaxy, is spatially resolved
over a region of ~65 pc in diameter and shows a regular rotation pattern
compatible with the global molecular and ionized gas kinematics. The line
profile is symmetric and well fitted by a Gaussian with an integrated flux of
37.0 +- 0.7 Jy km s-1 . Models predict this water transition as a potential
collisionally excited maser transition. On the contrary, in this galaxy, we
find that the 4_23-3_30 emission is primarily excited by the intense far-IR
radiation field present in its nucleus. According to our modeling, this
transition is a probe of deeply buried galaxy nuclei thanks to the high dust
optical depths (tau_100{\mu}m > 1, N_H > 1e24 cm-2) required to efficiently
excite it.Comment: Accepted for publication in A&A Letters; 4 pages, 5 figure
Differences in dry eye questionnaire symptoms in two different modalities of contact lens wear: silicone-hydrogel in daily wear basis and overnight orthokeratology
Purpose. To compare the ocular surface symptoms and signs in an adult population of silicone-hydrogel (Si-Hy) contact lens
(CL) wearers with another modality of CL wear, overnight orthokeratology (OK). Materials and Methods. This was a prospective
and comparative study in which 31 myopic subjects were fitted with the same Si-Hy CL and 23 underwent OK treatment for 3
months. Dry eye questionnaire (DEQ) was filled in at the beginning of the study and then after 15 days, 1 month, and 3 months
using each CL modality. The tear quality was evaluated with noninvasive tear break-up time. Tear production was measured with
Schirmer test. Tear samples were collected with Schirmer strips being frozen to analyze the dinucleotide diadenosine tetraphosphate
(Ap4A) concentration with High-Performance Liquid Chromatography (HPLC). Results. After refitting with ortho-k, a reduction
in discomfort and dryness symptoms at the end of the day ( < 0.05, 2
) was observed. No significant changes were observed in
Ap4A concentration in any group. Bulbar redness, limbal redness, and conjunctival staining increased significantly in the Si-Hy
group ( < 0.05, Kruskal–Wallis test). Conclusion. Discomfort and dryness symptoms at the end of the day are lower in the OK CL
group than in the Si-Hy CL group.The authors thank Paragon Vision Science and CooperVision
for donating the lenses. This work was partially supported by
the Xunta de Galicia by a predoctoral grant of the Plan I2C
2011–2015 and the Spanish SAF2013-44416-R and RETICS
RD12/0034/0003. It was also partially supported by Portuguese
Foundation for Science and Technology (FCT) in
the framework of projects PTDC/SAU-BEB/098391/2008 and
PTDC/SAU-BEB/098392/2008
Performance of three multipurpose disinfecting solutions with a silicone hydrogel contact lens
"Article ID 216932"To evaluate the clinical performance of a silicone hydrogel (Si-Hy) soft contact lens (CL) in combination with three
differentmultipurpose disinfecting solutions (MPDSs).Methods.Thiswas a prospective, randomized, single-masked, crossover, and
comparative study in which 31 habitual soft CL wearers were randomly assigned to one of the three MPDSs (Synergi, COMPLETE
RevitaLens, and OPTI-FREE PureMoist) for 1 month with a 1-week wash-out period between each exposure. All subjects were
successfully refitted with a Si-Hy CL (Biofinity). Subjects were then scheduled for follow-up visits after 1 month of lens wear, being
evaluated at 2 and 8 hours after lens insertion. Visual Analogue Scales (VAS) were used to gauge comfort rating. Results. The tarsal
conjunctiva showed a significantly different degree of lid redness between the MPDSs at the 2-hour visit (P < 0.05, Kruskal-
Wallis test), being lower for COMPLETE RevitaLens compared to the other two MPDSs (Mann-Whitney U test). Furthermore, a
significantly different degree of lid roughness at the 8-hour visit was seen (P < 0.05, Kruskal-Wallis test), being higher for Synergi
(Mann-Whitney U test).Thesubjective comfort was similar with the threeMPDSs. Conclusion. Tarsal conjunctival response should
be also considered in the context of the clinical performance of MPDs at the ocular surface.This work has been funded by an unrestricted grant from AMO Germany GmbH and it was also partially supported by Xunta de Galicia, Spain (Predoctoral Grant) and Fundacao para a Ciencia e Tecnologia, Portugal
Training physical education teachers for social justice: Effects of service-learning on Chilean and Spanish students
This article compares the effects of two Service-Learning models in Physical Education for teacher training from a Social Justice perspective. With a quantitative approach, comparative non-experimental design, the sample is made up of 90 university students from two universities: Chilean and Spanish, who have participated in Service-Learning experiences in the field of Physical Education. Statistical analysis and processing was performed using the SPSS v.25 program, set the significance level for all analyzes at P<0.05. The results of the study show significant differences on the effects produced by each Service-Learning model in initial training from a Social Justice perspective, used in each university. Equally, the results are in line with other studies that show how participation in Service-Learning experiences favors the development of critical reflexivity on Social Justification in future Physical Education teachers; in addition to granting them tools for the resolution of problematic events, based on real community situations.Este artĂculo compara los efectos de dos modelos de Aprendizaje-Servicio en EducaciĂłn FĂsica para la formaciĂłn de docentes desde una perspectiva de Justicia Social. Con un enfoque cuantitativo no experimental comparativo, la muestra se compone de 90 estudiantes universitarios de dos universidades: chilena y española que han participado en experiencias de Aprendizaje-Servicio en el ámbito de la EducaciĂłn FĂsica durante los cursos 2018/19 y 2019/20. El tratamiento y análisis estadĂstico se realizĂł mediante el programa SPSS v.25, estableciendo el nivel de significaciĂłn para todos los análisis en P<0,05. Los resultados del estudio muestran diferencias significativas sobre los efectos que produce cada modelo de Aprendizaje-Servicio en la formaciĂłn inicial desde una perspectiva de Justicia Social, utilizado en cada universidad. Asimismo, los resultados se encuentran en lĂnea con otros estudios que muestran cĂłmo la participaciĂłn en experiencias de Aprendizaje-Servicio favorece el desarrollo de la reflexibidad crĂtica sobre la Justifica Social en los futuros docentes de EducaciĂłn FĂsica; además de otorgarles herramientas para la resoluciĂłn de eventos problemáticos, a partir de situaciones comunitarias reale
Detection of cannabinoid receptors CB1 and CB2 within basal ganglia output neurons in macaques: changes following experimental parkinsonism
Abstract Although type 1 cannabinoid receptors (CB1-
Rs) are expressed abundantly throughout the brain, the
presence of type 2 cannabinoid receptors (CB2Rs) in neurons
is still somewhat controversial. Taking advantage of
newly designed CB1R and CB2R mRNA riboprobes, we
demonstrate by PCR and in situ hybridization that transcripts
for both cannabinoid receptors are present within
labeled pallidothalamic-projecting neurons of control and
MPTP-treated macaques, whereas the expression is markedly
reduced in dyskinetic animals. Moreover, an in situ
proximity ligation assay was used to qualitatively assess
the presence of CB1Rs and CB2Rs, as well as CB1R–CB2R
heteromers within basal ganglia output neurons in all
animal groups (control, parkinsonian and dyskinetic
macaques). A marked reduction in the number of CB1Rs,
CB2Rs and CB1R–CB2R heteromers was found in dyskinetic
animals, mimicking the observed reduction in CB1R
and CB2R mRNA expression levels. The fact that chronic
levodopa treatment disrupted CB1R–CB2R heteromeric
complexes should be taken into consideration when
designing new drugs acting on cannabinoid receptor
heteromers
Photovoltaic LiNbO3particles: Applications to Biomedicine/Biophotonics
Recently, a novel method to trap and pattern ensembles of nanoparticles has been proposed and
tested. It relies on the photovoltaic (PV) properties of certain ferroelectric crystals such as LiNbO3 [1,2].
These crystals, when suitably doped, develop very high electric fields in response to illumination with
light of suitable wavelength. The PV effect lies in the asymmetrical excitation of electrons giving rise to
PV currents and associated space-charge fields (photorefractive effect). The field generated in the bulk
of the sample propagates to the surrounding medium as evanescent fields. When dielectric or metal
nanoparticles are deposited on the surface of the sample the evanescent fields give rise to either
electrophoretic or dielectrophoretic forces, depending on the charge state of the particles, that induce
the trapping and patterning effects [3,4].
The purpose of this work has been to explore the effects of such PV fields in the biology and
biomedical areas. A first work was able to show the necrotic effects induced by such fields on He-La
tumour cells grown on the surface of an illuminated iron-doped LiNbO3 crystal [5]. In principle, it is
conceived that LiNbO3 nanoparticles may be advantageously used for such biomedical purposes
considering the possibility of such nanoparticles being incorporated into the cells. Previous experiments
using microparticles have been performed [5] with similar results to those achieved with the substrate.
Therefore, the purpose of this work has been to fabricate and characterize the LiNbO3 nanoparticles and
assess their necrotic effects when they are incorporated on a culture of tumour cells.
Two different preparation methods have been used: 1) mechanical grinding from crystals, and 2)
bottom-up sol-gel chemical synthesis from metal-ethoxide precursors. This later method leads to a more
uniform size distribution of smaller particles (down to around 50 nm). Fig. 1(a) and 1(b) shows SEM
images of the nanoparticles obtained with both method.
An ad hoc software taking into account the physical properties of the crystal, particullarly donor
and aceptor concentrations has been developped in order to estimate the electric field generated in
noparticles. In a first stage simulations of the electric current of nanoparticles, in a conductive media,
due to the PV effect have been carried out by MonteCarlo simulations using the Kutharev 1-centre
transport model equations [6] . Special attention has been paid to the dependence on particle size and
[Fe2+]/[Fe3+]. First results on cubic particles shows large dispersion for small sizes due to the random
number of donors and its effective concentration (Fig 2).
The necrotic (toxicity) effect of nanoparticles incorporated into a tumour cell culture subjected to
30 min. illumination with a blue LED is shown in Fig.3. For each type of nanoparticle the percent of cell
survival in dark and illumination conditions has been plot as a function of the particle dilution factor. Fig.
1a corresponds to mechanical grinding particles whereas 1b and 1c refer to chemically synthesized
particles with two oxidation states. The light effect is larger with mechanical grinding nanoparticles, but
dark toxicity is also higher. For chemically synthesized nanoparticles dark toxicity is low but only in
oxidized samples, where the PV effect is known to be larger, the light effect is appreciable.
These preliminary results demonstrate that Fe:LiNbO· nanoparticles have a biological damaging
effect on cells, although there are many points that should be clarified and much space for PV
nanoparticles optimization. In particular, it appears necessary to determine the fraction of nanoparticles
that become incorporated into the cells and the possible existence of threshold size effects.
This work has been supported by MINECO under grant MAT2011-28379-C03
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