A simulation study of irradiation effect on InAs/GaAsSb type II quantum dot structures.

Particles in space cause irradiation damage to the solar cells (SCs), resulting in the degradation of their performance. Quantum dot solar cells (QDSCs) have higher theoretical efficiency and better irradiation resistance than the conventional GaAs SCs, which makes them highly promising for application in space. In this paper, we study the proton irradiation effect on InAs/GaAs0.8Sb0.2 QDSCs by SRIM program. The simulation result shows that the InAs/GaAs0.8Sb0.2 QDSCs have fewer vacancies than GaAs SCs when irradiated with low-energy proton, which indicates that the InAs/GaAs0.8Sb0.2 QDSCs have better anti-irradiation characteristics. The study about displacements per atom and proton concentration in two SCs shows that protons with low energy and high irradiation fluences will cause more serious damage in InAs/GaAs0.8Sb0.2 QDSCs. In addition, the proton incident angle affects the vacancy distribution, while the number of QD layers has little effect on it.

Absorption enhancement in GaAs based quantum dot solar cells using double-sided nanopyramid arrays.

Quantum dot solar cells (QDSCs) are regarded as one of the most efficient devices due to their intermediate band structures. A suitable light-trapping (LT) strategy matching the absorption spectrum is important to improve the photocurrent conversion efficiency of QDSCs. In this paper, we have proposed a design of the periodically patterned top and bottom dielectric nanopyramid arrays for highly efficient light trapping in GaAs-based QDSCs. The dielectric nanopyramid arrays significantly improve the light absorption of QDSCs in the longer wavelength between 0.8 µm and 1.2 µm. In addition, this LT structure ensures a completely flat window layer and back surface field layer while passivating these semiconductor surfaces. For the optimized double-sided structure, the short-circuit current generated by QDSC is 34.32m A/c m 2, where the photocurrent from the quantum dots (QDs) is 5.17m A/c m 2. Compared to the photocurrent of the QDSC without an LT structure, the photocurrent of the double-sided structure is increased by 84%. The QD photocurrent of the double-sided structure is increased by 570% compared to that of the QDSC without the LT structure.

OsmiR159 Modulate BPH Resistance Through Regulating G-Protein γ Subunit GS3 Gene in Rice.

Brown planthopper (BPH) is the most destructive insect pest to rice that causes tremendous yield loss each year in rice planting Asia and South-East Asia areas. Compared with traditional chemical-based treatment, utilization of plant endogenous resistance is a more effective and environmental-friendly way for BPH control. Accordingly, quite a few quantitative trait loci (QTLs) for BPH resistance were cloned using forward genetics. However, BPH is apt to change quickly into new biotypes to overcome plant resistance, therefore, new resistance resources and genes are continuously needed. miRNAs are important regulators in both plant development and physiological regulation including immunity, and might be used as effective supplements for BPH resistance QTLs. miR159 is an ancient and conserved miRNA. In this study, we found that each OsMIR159 gene in rice responded to BPH feeding very obviously, and genetic function assay proved them to negatively regulate BPH resistance, with STTM159 showing resistance to BPH, and over expression of OsmiR159d susceptible to BPH. One target genes of OsmiR159, OsGAMYBL2, positively regulated BPH resistance. Further biochemical studies revealed that OsGAMYBL2 could directly bind to the promoter of G-protein γ subunit encoding GS3 gene and repress its expression. And genetically, GS3 responded to BPH feeding promptly and negatively regulated BPH resistance, GS3 over expression plants were susceptible to BPH, while GS3 knock-out plants were resistant to BPH. Thus, we identified new function of OsmiR159-OsGAMYBL2 in mediating BPH response, and revealed a new OsmiR159-G protein pathway that mediates BPH resistance in rice.

Performance optimization of In(Ga)As quantum dot intermediate band solar cells.

Quantum dot intermediate band solar cell (QD-IBSC) has high efficiency theoretically. It can absorb photons with energy lower than the bandgap of the semiconductor through the half-filled intermediate band, extending the absorption spectrum of the cell. However, issues in the IBSC, such as the strain around multi-stacking QDs, low thermal excitation energy, and short carrier lifetime, lead to its low conversion efficiency. In recent years, many efforts have been made from different aspects. In this paper, we focus on In(Ga)As QD-IBSC, list the experimental technologies used to improve the performance of the cell and review the recent research progress. By analyzing the effects of different technologies on conversion efficiency, the development direction of the In(Ga)As QD-IBSC in the future is proposed.

Source Contribution Analysis and Collaborative Assessment of Heavy Metals in Vegetable-Growing Soils.

Source quantification of heavy metals in farmland is essential for developing and implementing restoration strategies. We used various data analyses to identify and quantify sources of arsenic, cadmium, chromium, copper, mercury, nickel, lead, and zinc in vegetable-growing soils. A new method of collaborative assessment, combining soil environmental quality and agricultural product safety, showed that approximately 5.20% of cultivation systems were multi-contaminated by heavy metals. The nonlinear relationship between pollution sources and the comprehensive contamination situation was established, deriving from a fitted bivariate model. The model revealed that anthropogenic sources and natural origins accounted for 65.8-86.0 and 34.2-14.0% of the comprehensive pollution, respectively. These results suggested that both human activities and natural factors contributed to the decline of local soil quality and the influence of the former was more substantial than that of the latter.

Multiple factors impact the contents of heavy metals in vegetables in high natural background area of China.

A field survey was conducted to investigate the concentrations of chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in vegetables, corresponding cultivated soils and irrigation waters from 36 open sites in high natural background area of Wuzhou, South China. Redundancy analysis, Spearman's rho correlation analysis and multiple regression analysis were adopted to evaluate the contributions of impacting factors on metal contents in the edible parts of vegetables. This study concluded that leafy and root vegetables had relatively higher metal concentrations and adjusted transfer factor values compared to fruiting vegetables according to nonparametric tests. Plant species, total soil metal content and soil pH value were affirmed as three critical factors with the highest contribution rate among all the influencing factors. The bivariate curve equation models for heavy metals in the edible vegetable tissues were well fitted to predict the metal concentrations in vegetables. The results from this case study also suggested that it could be one of efficient strategies for clean agricultural production and food safety in high natural background area to breed vegetable varieties with low heavy metal accumulation and to enlarge planting scale of these varieties.

Low-Grade Myofibroblastic Sarcoma in the Mandibular Canal: A Case Report.

Low-grade myofibroblastic sarcoma (LGMS) represents an atypical myofibroblastic tumor characterized by a diffusely infiltrating pattern of spindle-shaped tumor cells. It was classified as a distinct soft tissue tumor by the World Health Organization in 2002. LGMS occurs mostly in adult patients and has a predilection for the head and neck region. So far, only a few cases of LGMS located in the mandible have been reported. Aggressive surgical resection with clear margins is the primary treatment for LGMS. Because of its rarity, reports of radiation therapy are limited, and the therapeutic effect is still controversial. We present the case of an 8-year-old girl with LGMS of the mandibular canal to highlight the clinical features and rarity and to improve the understanding of the therapeutic effect of radiotherapy on LGMS.

[Effects of water temperature and feeding on respiratory metabolism of juvenile Salvelinus fontinalus].

The oxygen consumption and ammonia excretion rates of juvenile brook trout (Salvelinus fontinalus) under satiation and starvation were measured at different levels of water temperature [(5.5 +/- 0.5), (8.5 +/- 0.5), (11.5 +/- 0.5), (14.5 +/- 0.5), (17.5 +/- 0.5) degrees C], aimed to study the effects of water temperature and feeding on the respiratory metabolism of the fish. Under satiation, the oxygen consumption and ammonia excretion rates of juvenile S. fontinalus at the five temperature levels increased rapidly to the maximum, and then decreased gradually to the initial state. The regression equations of oxygen consumption rate (OR) and ammonia excretion rate (NR) to water temperature (t) were OR = -0.0601 t4 + 2.5542 t3 - 39.256 t2 + 276.26 t - 598.75 (R2 = 1, 4.5 degrees C < t < 17.5 degrees C) and NR = - 0.0020 t4 + 0.0826 t3 - 1.2318 t2 + 8.6186 t - 18.838 (R2 = 1, 4.5 degrees C < t < 17.5 degrees C), respectively. Under starvation, the regression equations were OR = 13.723 t(0.9738) (R2 = 0.9974, 4.5 degrees C < t < 17.5 degrees C) and NR = 0.1687 t(1.0896) (R2 = 0.9977, 4.5 degrees C < t < 17.5 degrees C), respectively. The optimal temperature range was 11.5 degrees C-14.5 degrees C. The juvenile S. fontinalus in starvation was heavily depended on fat and carbohydrates.