Search

[Display omitted] • High-quality Ga 2 O 3 heterostructures grown via LMBE with lattice/energy band matching. • Modulating APDs' voltage and dark current by adjusting MgO layer thickness. • The impact of the barrier layer on the nBn structure APDs performance was systematically studied. • The fabrication of Ga 2 O 3 -based solar-blind APDs with the current optimal performance has been achieved. Ga 2 O 3 -based solar-blind avalanche photodetectors (APDs) offer advantages such as compactness, low power consumption, and high stability. They could improve the integration and reliability of solar-blind photodetectors, and serve as a viable substitute for photomultiplier tubes (PMTs) in deep ultraviolet signal detection. We have previously demonstrated that the n-Barrier-n (nBn) structure, composed of Ga 2 O 3 /MgO/Nb:SrTiO 3 heterostructure, can efficiently reduce the dark current and enhance the reverse breakdown voltage due to the increased conduction band offsets. The barrier layer is a key factor in determining the device performance in the nBn heterostructure. Hence, we further optimize the study by varying the thickness of the barrier layer MgO to examine its effect on the devices. This modulation can affect the avalanche multiplication process, and thus enable the tuning of APDs' performance. In this paper, we present the optimized thin film growth process, and the systematic investigation of the responsivity and gain of the device with different barrier layer thicknesses. The optimal performance was achieved with 25 nm MgO thickness. We also explore the underlying mechanism to elucidate the role of the barrier layer. Our results provide insights into the influence of barrier layer thickness in the nBn structure. [ABSTRACT FROM AUTHOR]

Poly(methyl methacrylate) (PMMA) is a synthetic polymer that has been widely used in various medical implants. Traditionally considered a biologically inert material, it is now understood that PMMA may have proinflammatory properties. Here, we present a proof-of-concept study of the effect of PMMA on CD4 T cells. Using particulate PMMA, a material that resembled wear debris in orthopedic implants, to stimulate whole peripheral blood mononuclear cells, we found that the expression of IFNgamma, IL-4, IL-17, and TGFbeta could all be upregulated in CD4 T cells in a manner that was dependent on the dose of particulate PMMA. Furthermore, compared to direct anti-CD3/CD28 stimulation, PMMA preferentially stimulated the expression of IFNgamma and IL-17 but not the expression of IL-4 or TGFbeta. Interestingly, the presence of autologous monocytes was required, since PMMA had no stimulatory effect on isolated CD4 T cells. We further demonstrated that direct monocyte-CD4 T cell contact was required, and the costimulatory molecules CD80 and CD86 were involved for the optimal stimulation of CD4 T cells. PMMA also directly mediated the death of CD4 T cells in a manner that was dependent on dose but independent of the presence of monocytes. Overall, our study revealed that PMMA could induce CD4 T cell death, and also could result in CD4 T cell activation with a preference toward proinflammatory responses in a monocyte-dependent manner. [ABSTRACT FROM AUTHOR]

With the continuing consumption of resources and increasingly prominent environmental issues, microalgal resource utilization has received extensive attention. In this study, based on the microalgal investigation in desert biological soil crusts (BSCs) using pyrosequencing technology, the cultivated crust microalgae were further isolated in order to obtain high quality microalgae for resource utilization. The results showed that with crust development and succession, microalgal diversity gradually decreased, including the number of operational taxonomic units (OTUs) and genus, although Microcoleus always was the dominant genera. Pyrosequencing obtained 630 OTUs of cyanobacteria, 25 OTUs of green algae and 9 OTUs of diatom; however, part of cultivated microalgae still could not yet be detected due to the DNA extraction preferences and errors caused by PCR amplification. After isolation, four strains were purified and cultivated, including two filamentous cyanobacteria Microcoleus vaginatus BSC-06 and Scytonema javanicum BSC-39, and two unicellular green algae Chlorella sp. BSC-24 and Monoraphidium dybowskii BSC-81. The two green algae grew fast (>250 mg L -1  d -1 ), and achieved high lipid productivity up to 75–85 mg L -1  d -1 , with lipid content of 28.7–39.0%, thus was considered as promising feedstock for biodiesel production. In addition, the two crust cyanobacteria could be used to construct artificial cyanobacterial soil crusts in desertification control, although their biomass accumulation was not as high as that in the green algae. Ultimately, combining biodiesel production with desertification control would not only improve desert environments, but also provide ideal places for the local microalgal resource exploitation, further promoting desert socioeconomic development. [ABSTRACT FROM AUTHOR]

In this study, based on the characteristic of lanthanide in oxygen storage capacity, a series of Pr a Ti b O x composite supports with different mole ratios of Pr to Ti and the corresponding Au catalysts were prepared - to investigate the oxidation of CO under CO 2 -rich atmosphere with lean oxygen content. A significant promotion in CO conversion rate over the catalyst with a molar ratio of Pr:Ti = 1:2 and a very high catalytic stability was also obtained. The addition of optimal Pr will make smaller gold particles, provide higher capacity in surface reactive oxygen releasing at low temperatures and weaken the deposition of carbonates in CO 2 -rich atmosphere. However, more Pr will strongly interact with gold, which leads to the majority of Au+ species in the catalysts and thus lower the catalytic activity. This study may provide a potential application of rare earth elements in sealed CO 2 -laser. [Display omitted] • The Pr a Ti b O x composites supported Au catalysts were studied for CO oxidation with CO 2 -rich feed. • The optimal catalyst was found with a molar ratio of Pr:Ti = 1:2. • Good catalytic performance correlated to the easy surface reactive oxygen releasing and weak deposition of carbonates. • The majority of Au+ species in the catalysts with higher Pr content results in worse performance. [ABSTRACT FROM AUTHOR]

The carbon cycle (C-cycle) is the most important and complex biogeochemical cycle in soil ecosystems, but our understanding of C-cycle at the community level remains limited. Biocrusts are known ecosystem engineers and represent ideal model systems for biogeochemical cycling studies. Here, metagenomic sequencing based on five repeated collections of four types of biocrusts revealed a low abundance of genes related to light-driven inorganic carbon fixation, and high abundance of genes related to the chemical energy-driven degradation of macromolecular organic carbon (OC), fermentation, aerobic respiration, and CO oxidation. For OC decomposition, genes mediating starch/glycogen and cellulose degradation were most abundant during the initial complex OC degradation, as were genes mediating fermentation during terminal steps of OC decomposition. To assess successional changes in carbon cycle, the metagenomic data were combined with absolute quantification via GeoChip, as well as key enzyme activity measurements. Inorganic carbon fixation, fermentation, CH 4 oxidation, and both starch/glycogen and peptidoglycan degradation decreased during succession. However, several high efficiency processes, as well as CO oxidation and most types of OC degradation, increased. Co-occurrence networks revealed that C-cycle in biocrusts consists of an assimilation module, akin to primary production, and a dissimilation module, comparable to secondary production; dynamic changes in the relationships between C-cycle pathways and microbial community composition occurred during succession. The two C-cycle modules were connected by the Calvin-Benson-Bassham cycle, as well as ethanol and propionate fermentation; the modules were balanced by drought and salinity. Collectively, these results improve our understanding of C-cycle pathways and regulatory mechanisms in biocrust succession, and provide a basis for future multi-omics studies of these systems. • Inorganic carbon fixation was low, with trace gases as energy supplement. • The carbon cycle in biocrusts showed significant dynamics during succession. • Two essential modules in the carbon cycle were found with co-occurrence network. • Carbon assimilation and dissimilation were balanced by drought and salinity. [ABSTRACT FROM AUTHOR]

Emerging applications of force-sensitive manipulation with the requirements on grasping safety and efficiency pose significant challenges on the design of compliant constant-force mechanisms with large operating ranges. In this paper, we propose a novel curved-beam based quasi-constant force mechanism fully compatible with the additive manufacturing technology, which is configurable with appropriate arc-elements to achieve quasi-constant force output with a large motion stroke. We develop an analytical model to describe the static deformation behavior of the proposed mechanism and analyze the performance sensitivity of its structural parameters, with which we also propose the optimization formulation and general guidelines for the design of curved-beam based compliant quasi-constant force mechanisms to meet force and displacement requirements. Finite element analysis and experiments are also conducted to comprehensively evaluate the proposed design, demonstrating significant performance improvement over existing results. • A novel quasi-constant force mechanism based on curved-beam is proposed. • An analytical model of multi-sectional curved-beam is derived. • Parameter optimization and design guidelines for quasi-constant force mechanism are provided. • Experimental validations of the proposed method with demonstrated performance improvement. [ABSTRACT FROM AUTHOR]

• Child care institutions(CCI) in Japan are saving children who come from poor and problem families. • To get out from their original families, these children must behave as 'decent children'. • Entering college is a huge success, but disciplines in the CCI makes them have troubles in college. • CCI children can enter and graduate from low-rank colleges. • After graduation, their jobs with a low salary will head them to the path of poverty again. The purpose of this paper is to clarify the process of going to college and subsequent college life of those who have experiences of entering Child Care Institutions (CCI) in Japan and to discuss higher education policies concerning 'child poverty' based on the results. This paper focuses on children who escaped from unstable families and could attain higher education in Japan. Particularly, this paper explored the experiences of several children who entered Child Care Institutions (CCI) and then continued their studies in college and examined the limitation of the support system for poor children in Japan. In this research, mixed method will be used. A questionnaire survey of students at University X and interviews towards 16 college students who had experiences of staying in CCI were conducted. The results are as follows: 1) Those who have entered CCI have chosen to go to university while internalizing the expectations of the surrounding staff. 2) However, happiness shared between the institution staff and the students are ended up entering university. 3) Those who have entered CCI have changed their thinking about employment and have financial difficulties after entering university. From there, it can be seen that the students are concerned about the gap between institutional life and university life in terms of building social relationship capital and rebounding to a disciplined life. [ABSTRACT FROM AUTHOR]

• The SSEResNet feature fusion backbone network based on ResNet101 is designed by using SENet attention module and CSPNet enhancement module. • A visual monitoring method of laser cleaning quality based on improved Cascade R-CNN is proposed by using SSEResNet, BiFPN and Soft-NMS. • A visual monitoring method of surface quality after laser cleaning based on SSEResNet101 regression model is proposed by reforming SSEResnet backbone network. • The effects of four different learning rate decay strategies on the two proposed deep learning models are studied. In order to protect the substrate during the cleaning process as well as evaluate the cleaning effect and surface quality after laser cleaning of aircraft coatings, a visual monitoring method based on deep learning is proposed. In this paper, the data sets of "flame recognition-cleaning quality evaluation" and "optical image-surface roughness" are constructed and data enhancement is performed. The SSEResNet backbone network which can effectively extract the details of the input image is designed by using the feature fusion method. The Cascade R-CNN object detection model is improved by using SSEResNet, BiFPN and Soft-NMS, and the SSEResNet101 regression model which can directly predict surface roughness from optical images is proposed based on ResNet101. Model comparison and ablation experiments show that the above two deep learning models proposed by us have excellent detection ability and regression prediction performance, and can realize flame recognition, cleaning effect judgment during laser cleaning as well as post-cleaning surface quality evaluation. In this paper, the effects of four different learning rate decay strategies on the models are further studied. The results show that the training effect of CosineAnnealing with warm restart method is the best. In SSEResNet101 model, the training mean square error (MSE) loss is 0.0249, the mean absolute error (MAE) is 0.278μm, and the test MAE is 0.245μm; In improved Cascade R-CNN model, the mean average precision (mAP) value of intersection over union (IoU=0.6) reaches 93.6%. [ABSTRACT FROM AUTHOR]