Dynamics in the ordered and disordered phases of barocaloric adamantane.

High-entropy order-disorder phase transitions can be used for efficient and eco-friendly barocaloric solid-state cooling. Here the barocaloric effect is reported in an archetypal plastic crystal, adamantane. Adamantane has a colossal isothermally reversible entropy change of 106 J K-1 kg-1. Extremely low hysteresis means that this can be accessed at pressure differences less than 200 bar. Configurational entropy can only account for about 40% of the total entropy change; the remainder is due to vibrational effects. Using neutron spectroscopy and supercell lattice dynamics calculations, it is found that this vibrational entropy change is mainly caused by softening in the high-entropy phase of acoustic modes that correspond to molecular rotations. We attribute this difference in the dynamics to the contrast between an 'interlocked' state in the low-entropy phase and sphere-like behaviour in the high-entropy phase. Although adamantane is a simple van der Waals solid with near-spherical molecules, this approach can be leveraged for the design of more complex barocaloric molecular crystals. Moreover, this study shows that supercell lattice dynamics calculations can accurately map the effect of orientational disorder on the phonon spectrum, paving the way for studying the vibrational entropy, thermal conductivity, and other thermodynamic effects in more complex materials.

Naturally occurring cell death in the cerebral cortex of the rat and removal of dead cells by transitory phagocytes.

Regressive phenomena are common during the development of the nervous tissue. Among them, naturally occurring cell death has been observed in several regions of the nervous system. Cell death in the somatosensory cortex and medial cortical regions (hind limb, frontal cortex 1, frontal cortex 2, retrosplenial agranular, retrosplenial granular [Zilles K. et al. (1980) Anat. Embryol. 159, 335-360]) as well as in the cortical subplate (future subcortical white matter) in the rat mainly occurs during the first 10 days of postnatal life with peak values of 3.1 dead cells per 1000 live neurons at the end of the first week. Cell death progresses from birth to day 7 with a predominance of dead cells in the subplate and in layers II-III. Later, dead cells are more dispersed in the cerebral cortex, but a significant amount is still present in the subcortical white matter. This pattern correlates with the arrival and settlement of cortical afferents at the different cortical levels, as described in other studies, and points to the likelihood that transitory cellular populations are important clues in the modelling of the cerebral cortex during normal development. Transitory populations of macrophages (amoeboid or nascent microglial cells) that appear in great numbers during the same period and in the same regions are involved in the removal of dead cells.

Formation and growth of the cerebral convolutions. II. Cell death in the gyrus suprasylvius and adjoining sulci in the cat.

Cell death, calculated by counting pyknotic nuclei to assess the number of dying cells, in the gyrus suprasylvius (GS-Syl) and adjoining sulci sulcus lateralis (SL) and sulcus suprasylvius (SS-Syl) was studied in cats aged 5, 15, 25 days and 6 months. Three patterns of cell death were characterized: (1) an ascending gradient from the inner to the upper cortical layers; (2) a lateromedial gradient from the SS-Syl towards the SL; and (3) a predominance of cell death in the sulcal zones. These patterns are in accordance with the sequence of cortical neurogenesis, the lateromedial pattern of the whole formation and growth of the GS-Syl and adjoining sulci, and the differences in the cortical thickness between the sulci and the gyral crown.

[Immunohistochemistry: another criterion for typing oncocytomas of the salivary gland. A case report]. / La inmunohistoquímica: un criterio más para la tipificación de los oncocitomas de glándula salivar. A propósito de un caso.

Oncocytoma of the salivary gland is uncommon and its histogenesis and pattern of evolution are debated. The criteria for malignancy are not well established. We report a morphologically benign oncocytoma of the parotid gland that was studied using various cell proliferation and tumor markers. These markers may have prognostic value and correlate with the aggressiveness of the tumor.

Formation and growth of the cerebral convolutions. I. Postnatal development of the median-suprasylvian gyrus and adjoining sulci in the cat.

The postnatal development of these median-suprasylvian gyrus and adjoining sulci was studied in cats 1, 5, 15, 25 days and six months old. The median-suprasylvian gyrus (G.S.-Syl.) grows according to a lateral to medial intracortical gradient in which the adjoining sulci, sulcus lateralis (S.L.) and median-suprasylvian sulcus (S.S-Syl.), are considered to be fixed zones because of their relatively constant distance from the ventricular wall throughout the development. Thus the formation of the S.L. is a consequence of the increase in volume of the gyral region adjacent to this developing sulcus, whereas there is a smaller increase in volume of the gyral region adjacent to the almost fully formed, at birth, S.S-Syl. This increase in volume is associated with a regional increase in the number of nerve cells and with an increase in the density of neurons in the region adjacent to the S.L. as it fades in the region adjacent to the S.S-Syl. This process takes place from Day 1 until about Day 25 of postnatal life. An intralaminar displacement of nerve cells also occurs during the process of cortical folding:nerve cell columns converge towards the hilum in the gyral region, but the columns progressively curve following the concavity of the infolding in the sulcal zones; as a result, although the length of nerve cell columns tends to be preserved to some extent along the gyrus, the cerebral cortex is progressively thinner in the sulci than in the gyri and the molecular layer is progressively thicker in the former than in the latter. This process also occurs following a lateral to medial gradient in the G.S.-Syl. The present observations may suggest that cortical folding is largely dependent on intracortical mechanical forces but the regular distribution of the sulci, together with the orderly spatio-temporal pattern of gyral growth, points to the conclusion that this process may be controlled by extracortical signals.

Expresión de la catepsina D en epitelio escamoso cervical y neoplasia cervical intraepitelial / Cathepsin D expression in cervical squamous epithelia and cervical intraepithelial neoplasia

Objetivo: Determinar las positividades mediante técnicas inmunohistoquímicas de la catepsina D (CD) en nuestras muestras así como la intensidad y localización en el espesor del epitelio de los casos positivos para este marcador. Material y métodos: Nuestro estudio está formado por 113 muestras de tejido cervical divididas en 4 grupos: 30 casos de epitelio escamoso cervical normal (CC), 31 de neoplasia cervical intraepitelial grado 1 (CIN1), 27 de neoplasia cervical intraepitelial grado 2 (CIN2) y 25 de neoplasia cervical intraepitelial grado 3 (CIN3). Se obtienen cortes de tejido, tras su fijación e inclusión en parafina, en los que se aplica una técnica inmunohistoquímica específica para la detección de la CD. Resultados: La distribución de las positividades de este marcador fueron 0 por ciento para el CC, 48 por ciento para el CIN1, 33 por ciento para el CIN2 y 44 por ciento para el CIN3, con p= 0,00001 en la relación CC-CIN1, p = 0,0005 en la relación CC-CIN2 y p = 0,00005 en la relación CCCIN3 (el nivel de significación estadística aplicado ha sido del 5 por ciento). La diferencia en la distribución de las intensidades fue significativa en el grupo de tinción intensa: 6,6 por ciento para CIN1, 0 por ciento para CIN2 y 45 por ciento para CIN3 (p = 0,0476). Conclusión: La expresión de la CD en un alto porcentaje de CIN1 puede atribuirse a su función estimuladora de la mitosis, así como el aumento de intensidad en los CIN3 podría indicar la adquisición temprana de alteraciones propias del fenotipo metastásico. Son necesarios estudios posteriores para sentar como base de la oncogénesis cervical nuestras conclusiones (AU)