Temperature Is Sufficient to Condition a Flavor Preference for a Cold-Paired Solution in Rats

Increasing evidence suggests that stimulus temperature modifies taste signaling. However, understanding how temperature modifies taste-driven behavior is difficult to separate as we must first understand how temperature alone modifies behavior. Previous work has suggested that cold water is more rewarding and “satiating” than warm water, and water above orolingual temperature is avoided in brief-access testing. We explored the strength of cold water preference and warm water avoidance by asking: (1) if cold temperature alone was sufficient to condition a flavor preference and (2) if avoidance of warm stimuli is driven by novelty. We addressed these questions using custom-designed equipment that allows us to monitor and maintain solution temperatures. We conducted two-bottle preference tests, after pairing Kool-Aid flavors with 10 or 40 °C. Rats preferred the flavor paired with cold temperature, both while it was cold and for 1 day while solutions were presented at 22 °C. We then examined the role of novelty in avoidance of 40 °C. Rats were maintained on 10, 22, or 40 °C water in their home cage to increase familiarity with the temperatures. Rats were then subject to a series of brief-access taste tests to water or sucrose at 10 to 40 °C. Rats that had 40 °C experience licked more to 40 °C water, but not sucrose, during brief-access testing. In a series of two-bottle preference tests, rats maintained on 40 °C water had a decreased preference for 10 °C water when paired opposite 40 °C water. Together, these data contribute to our understanding of orosensory-driven behavior with water at different temperatures.

Molecular memory of periodic thermal stimulation in an immune complex

Proteins search their vast conformational space in order to attain the native fold and bind productively to relevant biological partners. In particular, most proteins must be able to alternate between at least one active conformational state and back to an inactive conformer, especially for the macromolecules that perform work and need to optimize energy usage. This property may be invoked by a physical stimulus (temperature, radiation) or by a chemical ligand, and may occur through mapping of the protein external environment onto a subset of protein conformers. We have stimulated with temperature cycles two partners of an immune complex before and after assembly, and revealed that properties of the external stimulus (period, phase) are also found in the characteristics of the immune complex (i.e. periodic variations in the binding affinity). These results are important for delineating the bases of molecular memory ex vivo and could serve in the optimization of protein based sensors.

Modulation of taste processing by temperature

Taste stimuli have a temperature that can stimulate thermosensitive neural machinery in the mouth during gustatory experience. Although taste and oral temperature are sometimes discussed as different oral sensory modalities, there is a body of literature that demonstrates temperature is an important component and modulator of the intensity of gustatory neural and perceptual responses. Available data indicate that the influence of temperature on taste, herein referred to as “thermogustation,” can vary across taste qualities, can also vary among stimuli presumed to share a common taste quality, and is conditioned on taste stimulus concentration, with neuronal and psychophysical data revealing larger modulatory effects of temperature on gustatory responding to weakened taste solutions compared with concentrated. What is more, thermogustation is evidenced to involve interplay between mouth and stimulus temperature. Given these and other dependencies, identifying principles by which thermal input affects gustatory information flow in the nervous system may be important for ultimately unravelling the organization of neural circuits for taste and defining their involvement with multisensory processing related to flavor. Yet thermal effects are relatively understudied in gustatory neuroscience. Major gaps in our understanding of the mechanisms and consequences of thermogustation include delineating supporting receptors, the potential involvement of oral thermal and somatosensory trigeminal neurons in thermogustatory interactions, and the broader operational roles of temperature in gustatory processing. This review will discuss these and other issues in the context of the literature relevant to understanding thermogustation.

Análisis de rugosidad y determinación de los desplazamientos en aleaciones de Níquel-Titanio mediante microscopia de fuerza atómica

Introducción: En este trabajo de investigación se analiza una aleación de Níquel (Ni) y Titanio (Ti). Este tipo de materiales poseen la propiedad Física de memoria de forma; la cual consiste en aplicarle una deformación inicial al material, este puede volver a su estado original aplicándole un estímulo externo (temperatura o fuerza). Materiales y métodos: Mediante la utilización de un Microscopio de Fuerza Atómica (AFM). Basados en la información suministrada por el AFM se obtuvieron datos de los desplazamientos que sufre el material utilizando regiones de muestreo de 1 x 1 micras. También, se realizó un análisis de la rugosidad del material, teniendo en cuenta la variación de la topografía a medida que se comprime la muestra. Resultados y Discusión: La transición en los materiales ocurre al pasar de una fase austenita a una fase martensitica cuando el material es sometido a una compresión siendo un estado final de la transformación más estable. Conclusiones: Cuando el AFM se emplea en modo de contacto permite observar como varía la topografía de la muestra lo cual determina el comportamiento de la rugosidad, evidenciada en una disminución del material a medida que se comprime y en el modo de contacto con fuerza lateral. Con el primero se logró observar la forma como rotan las partículas agrupadas en la superficie, cuando se le aplica una fuerza externa.Introduction: In this research an alloy of nickel (Ni) and Titanium (Ti) is analyzed. Such materials possess the physical property of shape memory; which consists of applying an initial deformation to the material, it can return to its original state by applying an external stimulus (temperature or power). Methods: Using an Atomic Force Microscope (AFM) and based on the information provided by the AFM data of displacement experienced by the material using sampling regions of 1 x 1 micron were obtained. Roughness analysis of the material, considering the topography variation as the sample is compressed was also carried out. Results and Discussion: The transition occurs in the material passing an austenite phase to a martensitic phase when the material is subjected to compression to be a final state of stable transformation. Conclusions: When the AFM is used in contact mode allows observing the change the topography of the sample which determine the behavior of the roughness, as evident in a decrease of material as it is compressed and in contact mode lateral force. With the former were able to observe how the grouped rotate on the surface, when an external force is applied particles.

A Comparative Analysis of Orientation on the Shape Memory Effect of Fabric Reinforced Shape Memory Polymer Composites

Shape memory polymer composites (SMPC) are a new kind of smart materials where many researches have been carried out. In SMPC, shape memory polymers serves as a matrix material and particles or fibers act as reinforcements. As structural applications demand structures to withstand load and stiffness, particles reinforced SMPC does not serve for it. Therefore fiber/fabric reinforced SMPC used widely for such applications. SMPC’S changes its shape during a typical thermo-mechanical cycle and retracts to its original shape upon external stimulus (temperature). Molecular mechanism is the driving force of these SMP’s. SMP consists of 1.molecular switches and 2. netpoints. This project deals with Epoxy shape memory resin (Matrix material) and fabrics such as Glass, Kevlar and Carbon (Reinforcements).A Comparative analysis was carried out to find which combination gives the best results by bend test. Different orientations were tried for bidirectional fabrics such as (0/90)3, (0/45)3, ((0/90)/(±45)/(0/90)) specimens. Finally it was concluded that Carbon fabric which has the orientation of (0/90/±45/0/90) gives better shape memory performance.