Feed-Forward Propagation of Temporal and Rate Information between Cortical Populations during Coherent Activation in Engineered In Vitro Networks.

Transient propagation of information across neuronal assembles is thought to underlie many cognitive processes. However, the nature of the neural code that is embedded within these transmissions remains uncertain. Much of our understanding of how information is transmitted among these assemblies has been derived from computational models. While these models have been instrumental in understanding these processes they often make simplifying assumptions about the biophysical properties of neurons that may influence the nature and properties expressed. To address this issue we created an in vitro analog of a feed-forward network composed of two small populations (also referred to as assemblies or layers) of living dissociated rat cortical neurons. The populations were separated by, and communicated through, a microelectromechanical systems (MEMS) device containing a strip of microscale tunnels. Delayed culturing of one population in the first layer followed by the second a few days later induced the unidirectional growth of axons through the microtunnels resulting in a primarily feed-forward communication between these two small neural populations. In this study we systematically manipulated the number of tunnels that connected each layer and hence, the number of axons providing communication between those populations. We then assess the effect of reducing the number of tunnels has upon the properties of between-layer communication capacity and fidelity of neural transmission among spike trains transmitted across and within layers. We show evidence based on Victor-Purpura's and van Rossum's spike train similarity metrics supporting the presence of both rate and temporal information embedded within these transmissions whose fidelity increased during communication both between and within layers when the number of tunnels are increased. We also provide evidence reinforcing the role of synchronized activity upon transmission fidelity during the spontaneous synchronized network burst events that propagated between layers and highlight the potential applications of these MEMs devices as a tool for further investigation of structure and functional dynamics among neural populations

In situ synchrotron X-ray diffraction analysis of deformation behaviour in Ti–Ni-based thin films

Deformation mechanisms of as-deposited and post-annealed Ti50.2Ni49.6, Ti50.3Ni46.2Cu3.5 and Ti48.5Ni40.8Cu7.5 thin films were investigated using the in situ synchrotron X-ray diffraction technique. Results showed that initial crystalline phases determined the deformation mechanisms of all the films during tensile loading. For the films dominated by monoclinic martensites (B19'), tensile stress induced the detwinning of type-II twins and resulted in the preferred orientations of (002)B19' parallel to the loading direction (|| LD) and (020)B19' perpendicular to the LD ([perpendicular] LD). For the films dominated by austenite (B2), the austenite directly transformed into martensitic variants (B19') with preferred orientations of (002)B19' || LD and (020)B19' [perpendicular] LD. For the Ti50.3Ni46.2Cu3.5 and Ti48.1Ni40.8Cu7.5 films, martensitic transformation temperatures decreased apparently after post-annealing because of the large thermal stress generated in the films due to the large differences in thermal expansion coefficients between the film and substrate

Diagnostic Utility of Electromagnetic Navigation Bronchoscopy Combined with Radial Probe Endobronchial Ultrasound in Peripheral Pulmonary Lesions

Background and objective With the application of high resolution computed tomography (CT), a large number of peripheral lung lesions were found. It put forward new challenge on clinical diagnosis and treatment for these peripheral lung lesions. Electromagnetic navigation bronchoscopy (ENB) and radial endobronchial ultrasound probe (R-EBUS) are new technologies used for the diagnosis of peripheral lung lesions. The aim of this study is to explore the application value of ENB combined with R-EBUS in the diagnosis of peripheral pulmonary lesions. Methods From September 2016 to November 2017, eighteen patients with thirty peripheral pulmonary lesions in the First Affiliated Hospital of Soochow University were enrolled. The ENB was performed on these patients who were detected peripheral lung lesions by chest HR-CT. After successful navigation, the lesion’s location was confirmed by R-EBUS, and specimens were acquired by needle aspiration, endoscopic cell brush and biopsy forceps. Results A total of eighteen patients with thirty lesions were enrolled in this study, the navigation success rate was 100%, the positive rate was 90%. The mean operation time was (95.61±28.74) min, and navigation time for each lesion was (25.90±11.29) min, and pneumothorax was observed in 1 case. Conclusion ENB combined with R-EBUS for the diagnosis of peripheral pulmonary lesions is safe and effective. This technique is worth promoting

Nanocapsular Dispersion of Cinnamaldehyde for Enhanced Inhibitory Activity against Aflatoxin Production by Aspergillus flavus

Cinnamaldehyde (CA) is marginally soluble in water, making it challenging to evenly disperse it in foods, and resulting in lowered anti-A. flavus efficacy. In the present study, nano-dispersed CA (nano-CA) was prepared to increase its aqueous solubility. Free and nano-dispersed CA were compared in terms of their inhibitory activity against fungal growth and aflatoxin production of A. flavus both in Sabouraud Dextrose (SD) culture and in peanut butter. Our results indicated that free CA inhibited the mycelia growth and aflatoxin production of A. flavus with a minimal inhibitory concentration (MIC) value of 1.0 mM, but promoted the aflatoxin production at some concentrations lower than the MIC. Nano-CA had a lower MIC value of 0.8 mM against A. flavus, and also showed improved activity against aflatoxin production without the promotion at lower dose. The solidity of peanut butter had an adverse impact on the antifungal activity of free CA, whereas nano-dispersed CA showed more than 2-fold improved activity against the growth of A. flavus. Free CA still promoted AFB1 production at the concentration of 0.25 mM, whereas nano-CA showed more efficient inhibition of AFB1 production in the butter

Stress memory materials and their fundamental platform

Smart materials for stress applications are both sought after in the industry and are also of academic interest. Motivated by the unexpected drastic differences in the cyclic thermomechanical responses between Tg and Tm shape memory polyurethanes (SMPU), we discovered a new class of polymers known as stress-memory materials. We revealed that stress memory is not guaranteed by the shape-memory effect (SME), but instead manifests itself as a unique behaviour of shape memory polymers (SMPs) possessing the extra characteristic of an enthalpy switch. Stemming from our findings on a rubbery switch, memory stress is realized from the entropic elasticity within rubbery chains of the SMP soft segments. Enthalpy in a Tm-switch, crystal switch, can modulate this entropic energy leading to stress-memory, whereas the Tg-switch is a second-order thermodynamic transition. Thus, a model needs two basic elements: entropy domination for spring elasticity and enthalpy modulation of entropy as a switch for the stress-memory polymer networks. This forms a fundamental platform for materials development in energy, smart devices, artificial muscles, biological and physical massage systems with polymers, and high entropy ceramics and metals.Institute of Textiles and Clothin

Toward a self-wired active reconstruction of the hippocampal trisynaptic loop: DG-CA3.

The mammalian hippocampus functions to encode and retrieve memories by transiently changing synaptic strengths, yet encoding in individual subregions for transmission between regions remains poorly understood. Toward the goal of better understanding the coding in the trisynaptic pathway from the dentate gyrus (DG) to the CA3 and CA1, we report a novel microfabricated device that divides a micro-electrode array into two compartments of separate hippocampal network subregions connected by axons that grow through 3 × 10 × 400 μm tunnels. Gene expression by qPCR demonstrated selective enrichment of separate DG, CA3, and CA1 subregions. Reconnection of DG to CA3 altered burst dynamics associated with marked enrichment of GAD67 in DG and GFAP in CA3. Surprisingly, DG axon spike propagation was preferentially unidirectional to the CA3 region at 0.5 m/s with little reverse transmission. Therefore, select hippocampal subregions intrinsically self-wire in anatomically appropriate patterns and maintain their distinct subregion phenotype without external inputs

An in vitro method to manipulate the direction and functional strength between neural populations.

We report the design and application of a Micro Electro Mechanical Systems (MEMs) device that permits investigators to create arbitrary network topologies. With this device investigators can manipulate the degree of functional connectivity among distinct neural populations by systematically altering their geometric connectivity in vitro. Each polydimethylsilxane (PDMS) device was cast from molds and consisted of two wells each containing a small neural population of dissociated rat cortical neurons. Wells were separated by a series of parallel micrometer scale tunnels that permitted passage of axonal processes but not somata; with the device placed over an 8 × 8 microelectrode array, action potentials from somata in wells and axons in microtunnels can be recorded and stimulated. In our earlier report we showed that a one week delay in plating of neurons from one well to the other led to a filling and blocking of the microtunnels by axons from the older well resulting in strong directionality (older to younger) of both axon action potentials in tunnels and longer duration and more slowly propagating bursts of action potentials between wells. Here we show that changing the number of tunnels, and hence the number of axons, connecting the two wells leads to changes in connectivity and propagation of bursting activity. More specifically, the greater the number of tunnels the stronger the connectivity, the greater the probability of bursting propagating between wells, and shorter peak-to-peak delays between bursts and time to first spike measured in the opposing well. We estimate that a minimum of 100 axons are needed to reliably initiate a burst in the opposing well. This device provides a tool for researchers interested in understanding network dynamics who will profit from having the ability to design both the degree and directionality connectivity among multiple small neural populations

Nano-Thymol Emulsion Inhibits <i>Botrytis cinerea</i> to Control Postharvest Gray Mold on Tomato Fruit

Thymol is a plant-derived natural compound with antimicrobial activity. However, we have little knowledge about the application of thymol in agriculture. One of the limitations is the high volatility and low aqueous solubility of thymol. Tomato gray mold caused by Botrytis cinerea is one of the most devastating postharvest diseases. In this study, we prepared a nano-emulsion of thymol (named as Nano-Thy) to form a stable O/W (oil in water) microemulsion. In vitro experiments showed that Nano-Thy had antifungal activity against B. cinerea by inhibiting mycelial growth and spore germination. Nano-Thy induced ROS accumulation in mycelia, further leading to lipid peroxidation, cell membrane damage, and subsequent cell death. Nano-Thy significantly prevented the infection of B. cinerea on fresh tomato fruits. Finally, we discussed the mechanisms and their significance in controlling postharvest disease of fruit crops