Loss of memory for auditory-spatial associations following unilateral medial temporal-lobe damage

The goal of the present experiment was to determine the role of medial temporal-lobe structures in episodic memory of auditory-spatial associations. By using a two-alternative forced choice paradigm in which an association between eight different sounds and their spatial location must be recognized, learning abilities over 10 learning sessions were tested in 19 patients who had undergone a right or a left medial temporal-lobe resection for the relief of intractable seizures as well as in nine normal control participants. The data demonstrated that significant learning took place over the successive sessions for all the participants. In addition, the results showed that patients with left but not right medial temporal-lobe lesion were impaired in this learning task as compared to normal participants, suggesting the predominant implication of left medial temporal-lobe structures in auditory-spatial associative learning. The predominant role of left hemisphere structures in this memory task could be explained by a spatial categorical coding, which was enhanced by the use of eight loud-speakers. This result also suggests that the ability to store an episodic event associated with a rich spatial (or temporal) context depends on the left medial temporal-lobe structures. Thus, this finding provides an interesting parallel with data obtained in the visual modality by documenting for the first time the role of the left medial temporal-lobe in episodic learning of auditory-spatial associations

Polycarbonate polymer surface modication by extreme ultraviolet (EUV) radiation

The degree of the biocompatibility of polycarbonate (PC) polymer used as biomaterial can be controlled by surface modification for various biomedical engineering applications. In the past, PC samples were treated by excimer laser for surface reorganization however associated process alteration of bulk properties is reported. Extreme ultraviolet radiation can be employed in order to avoid bulk material alteration due to its limited penetration. In this study, a 10 Hz laser-plasma EUV source based on a double-stream gas-pu_ target irradiated with a 3 ns and 0.8 J Nd:YAG laser pulse was used to irradiate PC samples. The PC samples were irradiated with different number of EUV shots. Pristine and EUV treated samples were investigated by scanning electron microscopy and atomic force microscopy for detailed morphological characterization of micropatterns introduced by the EUV irradiation. Associated chemical modifications were investigated by X-ray photoelectron spectroscopy. Pronounced wall-type micro- and nanostructures appeared on the EUV modified surface resulting in a change of surface roughness and wettability

Effect of powder metallurgy synthesis parameters for pure aluminium on resultant mechanical properties

In this work, pure aluminium powders of different average particle size were compacted, sintered into discs and tested for mechanical strength at different strain rates. The effects of average particle size (15, 19, and 35 μm), sintering rate (5 and 20 °C/min) and sample indentation test speed (0.5, 0.7, and 1.0 mm/min) were examined. A compaction pressure of 332 MPa with a holding time of six minutes was used to produce the green compacted discs. The consolidated green specimens were sintered with a holding time of 4 h, a temperature of 600 °C in an argon atmosphere. The resulting sintered samples contained higher than 85% density. The mechanical properties and microstructure were characterized using indentation strength measurement tests and SEM analysis respectively. After sintering, the aluminium grain structure was observed to be of uniform size within the fractured samples. The indentation test measurements showed that for the same sintering rate, the 35 μm powder particle size provided the highest radial and tangential strength while the 15 μm powder provided the lowest strengths. Another important finding from this work was the increase in sintered sample strength which was achieved using the lower sinter heating rate, 5 °C/min. This resulted in a tangential stress value of 365 MPa which was significantly higher than achieved, 244 MPa, using the faster sintering heating rate, 20 °C/min

Electroadhesive Auxetics as Programmable Layer Jamming Skins for Formable Crust Shape Displays

Shape displays are a class of haptic devices that enable whole-hand haptic exploration of 3D surfaces. However, their scalability is limited by the mechanical complexity and high cost of traditional actuator arrays. In this paper, we propose using electroadhesive auxetic skins as a strain-limiting layer to create programmable shape change in a continuous ("formable crust") shape display. Auxetic skins are manufactured as flexible printed circuit boards with dielectric-laminated electrodes on each auxetic unit cell (AUC), using monolithic fabrication to lower cost and assembly time. By layering multiple sheets and applying a voltage between electrodes on subsequent layers, electroadhesion locks individual AUCs, achieving a maximum in-plane stiffness variation of 7.6x with a power consumption of 50 uW/AUC. We first characterize an individual AUC and compare results to a kinematic model. We then validate the ability of a 5x5 AUC array to actively modify its own axial and transverse stiffness. Finally, we demonstrate this array in a continuous shape display as a strain-limiting skin to programmatically modulate the shape output of an inflatable LDPE pouch. Integrating electroadhesion with auxetics enables new capabilities for scalable, low-profile, and low-power control of flexible robotic systems.Comment: Accepted to IEEE International Conference on Robotics and Automation (ICRA 2023

Genetic variability and correlation studies for growth and yield characters in chilli (Capsicum annuum L.)

Twenty three genotypes were used to study the genetic variability, heritability, genetic advance and correlation for growth and yield contributing characters in chilli under Kashmir conditions. Significant variations were observed for all the characters studied except for days to flowering and crop duration [mature (green) as well as dry (red)]. High Phenotypic Coefficient Variation (PCV) and Genotypic Coefficient Variation (GCV) were recorded for number of fruits plant-1, fruit weight and dry (red) yield. All the characters showed high heritability estimates. However, number of the fruits plant-1, green fruit yield plant-1, dry (red) yield plant-1, number of seeds plant-1 and plant height exhibited high genetic advance as percentage of mean indicating additive gene effect. Fruit yield (green and red) plant-1 was positively and significantly correlated with number of fruits plant-1 and fruit length. It revealed that the characters viz., plant height, fruit length, number of fruits plant-1, fruit weight and fruit yield (green & red) are the most important traits for genetic improvement of chilli. &nbsp