1,054 research outputs found
An organic solution to the Kelvin myth?: White light with true color temperature via exciplex formation
Abstract Many white light sources are described as having a "color temperature", a practice that has been termed the "Kelvin myth", since, in general, only incandescent light-emitters have a spectral distribution which closely approximates that of a black-body curve. We show that the white light emitted, via exciplex formation, from blends of two blue-emitting organic materials, has the same spectral form as black-body light, as perceived by the human eye. The color temperature is tunable, depending on the relative concentrations of the two materials. This suggests that organics could provide a white light source with a tunable, true, color temperature
Imbalance between pro-apoptotic and pro-survival factors in human retinal pericytes in diabetic-like conditions
Recurrent Non-Hodgkin’s lymphoma in the uterine cervix: a case report and a review of the literature
Background. Lymphomas are a heterogeneous group of malignant lymphoproliferative diseases. As primary localization, the most common histological subtype of female genital lymphomas is a Non-Hodgkin Lymphoma (NHL), the diffuse large B-cell type. However cervical relapse of NHL is a very rare condition (0.3%). Case presentation. A 42-year-old Peruvian woman experienced relapse of NHL with uterine localization. She complained at first of abnormal vaginal bleeding and stranguria. The cervical biopsy performed showed a diffuse large B-cell lymphoma in the uterine cervix. The lack of clinical studies on this topic and its rarity make this type of recurrence very difficult to treat. Conclusions. In case of a woman with vaginal bleeding and history of NHL, a disease relapse should always be considered, and a biopsy should be performed to confirm the diagnosis. © 2023, EDRA S.p.A. All rights reserved
Rigid ball-polyhedra in Euclidean 3-space
A ball-polyhedron is the intersection with non-empty interior of finitely
many (closed) unit balls in Euclidean 3-space. One can represent the boundary
of a ball-polyhedron as the union of vertices, edges, and faces defined in a
rather natural way. A ball-polyhedron is called a simple ball-polyhedron if at
every vertex exactly three edges meet. Moreover, a ball-polyhedron is called a
standard ball-polyhedron if its vertex-edge-face structure is a lattice (with
respect to containment). To each edge of a ball-polyhedron one can assign an
inner dihedral angle and say that the given ball-polyhedron is locally rigid
with respect to its inner dihedral angles if the vertex-edge-face structure of
the ball-polyhedron and its inner dihedral angles determine the ball-polyhedron
up to congruence locally. The main result of this paper is a Cauchy-type
rigidity theorem for ball-polyhedra stating that any simple and standard
ball-polyhedron is locally rigid with respect to its inner dihedral angles.Comment: 11 pages, 2 figure
Gravitational and axial anomalies for generalized Euclidean Taub-NUT metrics
The gravitational anomalies are investigated for generalized Euclidean
Taub-NUT metrics which admit hidden symmetries analogous to the Runge-Lenz
vector of the Kepler-type problem. In order to evaluate the axial anomalies,
the index of the Dirac operator for these metrics with the APS boundary
condition is computed. The role of the Killing-Yano tensors is discussed for
these two types of quantum anomalies.Comment: 23 page
White light emission from blends of blue-emitting organic molecules: A general route to the white organic light-emitting diode?
We show that all possible binary combinations of molecules from four different families of organics - a diamine derivative, N,N′-bis(3methylphenyl)-N,N′-diphenylbenzidine, an oxidiazole derivative, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, a substituted thiophene dioxide, 2,5-bis(trimethylsilyl thiophene)-1,1-dioxide, and poly(9-vinylcarbazole) - produce white or near-white emission. We suggest that this is due to exciplex formation, and that this is likely to be a general phenomenon for blends of blue-emitting aromatic organics. This implies that films of spin-coated blends of blue-emitting organics represent a general, simple, and cheap route to white-emitting organic light-emitting diodes
Algunos métodos de predicción de la temperatura mÃnima
Las heladas constituyen un fenómeno atmosférico que puede afectar el normal desarrollo de ciertas especies vegetales. Algunos de los daños que ocasionan pueden ser disminuidos mediante técnicas de protección. Estas técnicas requieren, en algunos casos, de la predicción de la temperatura mÃnima del aire.
En este trabajo se presentan algunas expresiones destinadas a predecir la variación temporal y vertical de la temperatura. Esas expresiones fueron obtenidas mediante la ecuación de balance de calor en la interfase suelo-aire, las ecuaciones de difusión de calor en el suelo y en el aire y apropiadas condiciones iniciales y de contorno. Se comparan entre si los resultados encontrados mediante esas expresiones, obteniéndose que la inclusión de un mayor número de flujos de calor y de condiciones más realistas en la distribución inicial de la temperatura permite encontrar ura disminución menos acentuada de la temperatura de superficie.Frost is one of the atmospheric phenomena that affects the growth of vegetation. The damage by frost could be prevented by protection techniques. Most techniques, sometimes request the prediction of the minimum temperature of air. This paper presents some expressions for the prediction of the temporal and vertical variation of the temperature. These expressions are developed from the equation of energy balance at the interface soil-air, the heat diffusion equation, and the initial and boundary conditions. From the comparison between these expressions, it was found that the variation of surface temperature is smaller than when the heat flux is incluided, it is a most realistic boundary condition.Asociación Argentina de GeofÃsicos y Geodesta
Use of nano gold obtained by laser ablation for SEIRA analyses of colorants
The analysis of dyes in cultural heritage samples is a well-known challenging task, due to their inherent high tinting strength and consequent low concentration in the carrying matrix a fact that severely limits the number of analytical techniques that can be efficiently and micro-destructively employed for their detection and unambiguous identification. In the present study, an advanced and alternative SEIRA based analytical protocol for the analysis of small quantities of synthetic colorants has been proposed. The method has been set up for the identification of Acid Orange 7 (AO7) using Au nanoparticles obtained by laser ablation in solution (LASiS). Analyses have been performed applying a drop containing a mixture between the colorant and the Au colloidal solution in its unaggregated state on a gold coated glass slide for RAS (Reflection Absorption Spectroscopy) analysis. The first results showed that, thanks to the enhancement produced by the nanoparticles, it is possible to analyze small amount of diluted solutions containing the colorant. Thus, the method has been successfully applied for the analysis of few pieces of dyed wool, after the development of a suitable micro extraction procedure
New constraints on the origin of the ophiolitic rocks within sinorogenic turbiditic sequences at Cilento region (southern Italy)
Mafic igneous rocks (pillow lavas and gabbros) embedded as olistoliths within Miocene turbiditic sequences crop out in the Cilento area at the Mount Centaurino (Campania region, Southern Italy). The concentration of major oxides, as well as trace element ratios (Nb/Yb, Nb/Ta, Th/Nb) and the chondrite-normalized Rare Earth Elements (REE) patterns suggest a tholeiitic character with Mid Oceanic Ridge Basalts (MORB) affinity. The chemical composition of pillow lavas is consistent with magmas generated by 10% degrees of non-modal fractional partial melting, of a spinel-bearing MORB-type asthenospheric mantle. Regarding gabbros, the calculated composition of parental melts in equilibrium with the clinopyroxenes show a wide compositional range, and there are very different from the pillow basalts of the Mount Centaurino, suggesting that the clinopyroxenes might have derived from more evolved melts compared to those that produced the basalts. The origin of these olistoliths is not yet understood. Here we suggest that these rocks represent fragment of a dismantled accretionary wedge embedded during the deposition of the Cilento group sedimentary successions in a thrust top basin
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