Search

Coordination of neurite extension with surrounding glia development is critical for neuronal function, but the underlying molecular mechanisms remain poorly understood. Through a genome-wide mutagenesis screen in C. elegans, we identified dyf-4 and daf-6 as two mutants sharing similar defects in dendrite extension. DAF-6 encodes a glia-specific patched-related membrane protein that plays vital roles in glial morphogenesis. We cloned dyf-4 and found that DYF-4 encodes a glia-secreted protein. Further investigations revealed that DYF-4 interacts with DAF-6 and functions in a same pathway as DAF-6 to regulate sensory compartment formation. Furthermore, we demonstrated that reported glial suppressors of daf-6 could also restore dendrite elongation and ciliogenesis in both dyf-4 and daf-6 mutants. Collectively, our data reveal that DYF-4 is a regulator for DAF-6 which promotes the proper formation of the glial channel and indirectly affects neurite extension and ciliogenesis., Author summary In C. elegans sensory organ, the ciliated neuronal endings are wrapped in a luminal channel formed by glial cells, forming a specialized sensory compartment critical for sensory activity. Coordination of glial channel formation, dendritic tip anchoring and ciliogenesis are critical for the formation of a functional sensory compartment. DAF-6, a patched-related glial membrane protein, was reported to play an important role in glial channel morphogenesis, but the molecular function and regulatory mechanism of DAF-6 remain poorly understood. Here, we found that DYF-4, a glia-secreted protein, interacts and colocalizes with DAF-6, and functions in a same pathway as DAF-6 to regulate sensory compartment formation. We propose that DYF-4 is a novel regulator for DAF-6 to control sensory compartment formation.

This paper demonstrated a novel energy utilization that thermoelectric generation (TEG) device can achieve self-powering by radiative cooling (RC) continuously. An ultrathin TEG with a multilayer thermal emitter was fabricated to convert the heat from the environment into electricity directly by using radiative cooling. The TEG device was consisted of more than 46,000 P-N modules in series, and each two TE modules were connected by air bridge. Thermal emitter had 80.8% emissivity in the atmospheric window (8–13 µm). Besides, maximum temperature drop of 4 K was achieved. The output voltage of the TEG-RC reached up to 0.5 mV, and the TEG-RC exhibited a continuous average 0.18 mV output for 24 h. Extreme temperature gradients were surprisingly formed in cross section of 1.5 µm thick for micro/nano film materials.

Coordination of neurite extension with surrounding glia development is critical for neuronal function, but the underlying molecular mechanisms remain poorly understood. Through a genome-wide mutagenesis screen in C. elegans, we identified dyf-4 and daf-6 as two mutants sharing similar defects in dendrite extension. DAF-6 encodes a glia-specific patched-related membrane protein that plays vital roles in glial morphogenesis. We cloned dyf-4 and found that DYF-4 encodes a glia-secreted extracellular protein. Intriguingly, DYF-4 colocalizes with DAF-6 along the glial channel. Further investigations revealed that DYF-4 directly interacts with DAF-6 and regulates its proper membrane localization. Notably, reported glial suppressors of daf-6 could also restore dendrite elongation and ciliogenesis in both dyf-4 and daf-6 mutants. Collectively, our data suggest that secreted DYF-4 likely acts as a novel ligand/regulator for the patched-related receptor DAF-6 which promotes the proper formation of the glial channel and indirectly affects neurite extension and ciliogenesis.

Thermoelectric multilayer thin films used in nanoscale energy conversion have been receiving increasing attention in both academic research and industrial applications. Thermal transport across multilayer interface plays a key role in improving thermoelectric conversion efficiency. In this study, the cross-plane thermal conductivities of nano-constructed Sb2Te3/(Cu, Ag, Au, Pt) thermoelectric multilayer thin films have been measured using time-domain thermoreflectance method. The interface morphology features of multilayer thin film samples were characterized by using scanning and transmission electron microscopes. The effects of interface microstructure on the cross-plane thermal conductivities of the multilayer thin films have been extensively examined and the thermal transfer mechanism has been explored. The results indicated that electron–phonon coupling occurred at the semiconductor/metal interface that strongly affected the cross-plane thermal conductivity. By appropriately optimizing the period thickness of the metal layer, the cross-plane thermal conductivity can be effectively reduced, thereby improving the thermoelectric conversion efficiency. This work presents both experimental and theoretical understanding of the thermal transport properties of Sb2Te3/metal multilayer thin film junctions with important implications for exploring a novel approach to improving the thermoelectric conversion efficiency.

In order to utilize the miniaturization exothermic oxidation of methanol in the microelectronic device as an energy source rather than industrial waste, nano-heterojunctions between Si and 20 nm ultra-thin catalyst Pt3Cu or Pt film were fabricated to investigate the energy conversion of methanol in this study. Methanol was catalyzed by Pt3Cu or Pt to release energy, then electrons were excited and passed through the Schottky barrier of Pt3Cu/Si or Pt/Si, which were calculated to be 0.43 and 0.80 eV, respectively. Thereupon, hot electron current was formed in a ballistic transport mode. Pt3Cu, Pt and Si have good high temperature stability. Pt3Cu has a higher crystallinity and better electronic structure than Pt and is dominated by (111) crystal orientation. Thus, Pt3Cu has higher catalytic activity and stronger ability to overcome the toxicity of CO, making it easier to obtain stable hot electron current. The factors that affect the hot electron current are varied from chemical reaction rate to Au electrode structure with the increase of temperature. This work is likely to provide a new reference to enhance the methanol’s direct conversion effectively with a stable current in the solid-state way at different temperature. Herein we report for the first time achieving methanol as hot electron energy source. Therefore, the maximum utilization of energy could be realized by turning waste methanol into treasure.

A 20 nm flat fire pattern was prepared by magnetron sputtering (MTS) deposition using Pt/Al2O3 nanocatalytic structure. Atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM) were used to characterize the microstructure of nanocatalystic film. Uniform temperature distributions across the nanocatalytic surface as well as rapid temperature response were observed using infrared thermal microscope under various methanol/air mixed flows. We observed as high as 15 °C over 20 nm Pt/ Al2O3 layer (vertical thermal gradient > 750 °C/μm or 750,000 °C/mm); when the vertical temperature difference is about 5 °C the horizontal thermal gradient is larger than 1.33 °C/μm (or 1330 °C/mm). In addition, the nanoscale heat transfer mechanisms were explored based on the experimental data and theoretical model. The results indicate that this kind of patterned nanoscale fire has the advantages of rapid temperature response and uniform temperature distribution, as well as larger temperature gradient. The nanoscale thin catalytic fire exhibits excellent properties of ultra-low catalyst loading and high conversion efficiency which are suitable for energy conversion at nanoscale. To develop a controllable and localized ultrathin two-dimensional fire may provide a possibility of making chip-scale power MEMS in the near future.

Combustion is a chemical reaction that emits heat and light. Nanofire is a kind of flameless combustion that occurs on the micro–nano scale. Pt/Al2O3 film with a thickness of 20 nm can be prepared as a catalyst by micro–nano processing. When the methanol-air mixture gas passes through the surface of the catalyst, a chemical reaction begins and a significant temperature rise occurs in the catalyst region. Compared to macroscopic combustion, Nanofire has many special properties, such as large temperature gradients, uniform temperature distribution, and fast temperature response. The large temperature gradient is the most important property of Nanofire, which can reach 1330 K/mm. Combined with thermoelectric materials, it can realize the efficient conversion of chemical energy to electric energy. Nanoscale thickness offers the possibility of establishing thermal gradient. On the other hand, large thermal gradient has an effect on the transport properties of phonons and electrons in film materials. From these we can get the scale effects of heat. This article will provide an overview of the preparation, properties and applications of Nanofire, and then a comprehensive introduction to the thermal scale and thermal scale effects. Electronic supplementary material The online version of this article (10.1186/s40580-019-0175-4) contains supplementary material, which is available to authorized users.

Additional file 1. The simulation calculation of contact thermal resistance.

To develop a cost-effective biopesticide, spent mushroom substrate (SMS) extract was studied as a potential carbon source for cultivating Bacillus thuringiensis (Bt). Several pretreatments were compared to determine the optimal method for degrading cellulose to produce reducing sugars, including dilute sulfuric acid (0.5-2.0% v/v, 50-121°C, 1h), sodium hydroxide (0.5-2% w/v, 50-121°C, 1h), calcium hydroxide (0.2-4% w/v, 50-121°C, 1h), and hot water (50-121°C, 1h). Pretreatment was followed by standard enzymatic hydrolysis and fermentation. Results showed that the highest cellulose degradation was obtained using 2% dilute sulfuric acid pretreatment at 121°C for 1h, resulting in a high yield of reducing sugar (284.24 g/kg SMS). Sporulation was also highest using the same pretreatment. Use of SMS is not only an alternative way to commercialize Bt-based biopesticide, but also a potential solution for the environmental pollution associated with accumulation of the spent substrate of the mushroom industry.