Origin of Water-Stable CsPbX3 Quantum Dots Assisted by Zwitterionic Ligands and Sequential Strategies for Enhanced Luminescence Based on Crystal Evolution.

Water stability is a crucial issue always addressed for commercial practical application of perovskite quantum dots (QDs). Recent advances in ligand engineering for in situ synthesis of water-stable perovskite QDs have attracted growing interest. However, the exact mechanism remains unclear. Here, the function of 4-bromobutyric acid (BBA) and oleylamine (OLA) is systematically studied in water-stable CsPbX3 (X = Br and I) QDs and confirms that the zwitterionic ligands generated in situ by BBA and OLA are anchored on the QDs surface, thus preventing water from penetrating into the QDs. Cs4PbBr6 intermediate crystal found in the crystal structure evolution process of CsPbX3 QD further reveals a complete crystallization process: PbX2 + CsX + Br- → Cs4PbBr6 crystals + X-→ CsPbX3 QDs + Br-. Furthermore, it is found that the solvent coordination of the precursor solution has a significant effect on the crystallinity of Cs4PbBr6 intermediate crystal, while the Rb+ doping can effectively passivate the surface defects of CsPbX3 QDs, thereby jointly achieving photoluminescence quantum yields (PLQY) of 94.6% for CsPbBr3 QDs (88.2% for CsPbI3 QDs). This work provides new insights and guiding ideas for the green synthesis of high-quality and water-stable perovskite QDs.

Low-threshold AlGaN-based deep ultraviolet laser enabled by a nanoporous cladding layer.

We demonstrated an AlGaN-based multiple-quantum-well (MQW) deep ultraviolet (DUV) laser at 278 nm using a nanoporous (NP) n-AlGaN as the bottom cladding layer grown on the sapphire substrate. The laser has a very-low-threshold optically pumped power density of 79 kW/cm2 at room temperature and a transverse electric (TE)-polarization-dominant emission. The high optical confinement factor of 9.12% benefiting from the low refractive index of the nanoporous n-AlGaN is the key to enable a low-threshold lasing. The I-V electrical measurement demonstrates that an ohmic contact can be still achieved in the NP n-AlGaN with a larger but acceptable resistance, which indicates it is compatible with electrically driven laser devices. Our work provides insights into the design and fabrication of low-threshold lasers emitting in the DUV regime.

Exosomal circBBS2 inhibits ferroptosis by targeting miR-494 to activate SLC7A11 signaling in ischemic stroke.

Umbilical cord-mesenchymal stem cells (UC-MSCs)-derived exosomes have been considered as an effective treatment for ischemic stroke. CircRNA BBS2 (circBBS2) was demonstrated to be down-regulated in patients with ischemic stroke. However, the role of UC-MSCs-derived exosomal circBBS2 in ischemic stroke and potential mechanisms remain unclear. Hypoxia/reperfusion (H/R)-exposed SH-SY5Y cells and middle cerebral artery occlusion (MCAO)-treated rats were served as in vitro and in vivo models of ischemic stroke. Target gene expression was detected by qRT-PCR. Cell viability was assessed by MTT assay. Ferroptosis was determined by iron, MDA, GSH, and lipid ROS levels. Protein levels were measured by Western blotting. The target relationships among circBBS2, miR-494, and SLC7A11 were validated by RNA-pull down, RIP, and dual-luciferase reporter assays. TTC and HE staining were performed to evaluate cerebral infarction volume and neuropathological changes. circBBS2 was lowly expressed and ferroptosis was triggered in MCAO rats and H/R-stimulated SH-SY5Y cells. UC-MSCs-derived exosomes enhanced cell viability and restrained ferroptosis via increasing circBBS2 expression in SH-SY5Y cells. Mechanistically, circBBS2 sponged miR-494 to enhance the SLC7A11 level. Knockdown of miR-494 or SLC7A11 reversed the effects of silencing circBBS2 or miR-494 on ferroptosis of SH-SY5Y cells, respectively. Furthermore, UC-MSCs-derived exosomes attenuated ischemic stroke in rats via delivering circBBS2 to inhibit ferroptosis. UC-MSCs-derived exosomal circBBS2 enhanced SLC7A11 expression via sponging miR-494, therefore repressing ferroptosis and relieving ischemic stroke. Our findings shed light on a novel mechanism for UC-MSCs-derived exosomes in the treatment of ischemic stroke.

Early Identification of Rotten Potatoes Using an Electronic Nose Based on Feature Discretization and Ensemble Convolutional Neural Network.

The early identification of rotten potatoes is one of the most important challenges in a storage facility because of the inconspicuous symptoms of rot, the high density of storage, and environmental factors (such as temperature, humidity, and ambient gases). An electronic nose system based on an ensemble convolutional neural network (ECNN, a powerful feature extraction method) was developed to detect potatoes with different degrees of rot. Three types of potatoes were detected: normal samples, slightly rotten samples, and totally rotten samples. A feature discretization method was proposed to optimize the impact of ambient gases on electronic nose signals by eliminating redundant information from the features. The ECNN based on original features presented good results for the prediction of rotten potatoes in both laboratory and storage environments, and the accuracy of the prediction results was 94.70% and 90.76%, respectively. Moreover, the application of the feature discretization method significantly improved the prediction results, and the accuracy of prediction results improved by 1.59% and 3.73%, respectively. Above all, the electronic nose system performed well in the identification of three types of potatoes by using the ECNN, and the proposed feature discretization method was helpful in reducing the interference of ambient gases.

Effects of long-term different-scale rice-duck farming on the growth and yield of paddy rice.

BACKGROUND: To maintain rice production and increase revenue, rice-duck (RD) farming is a contemporary ecological cycle technology that has been widely used in Asia. However, due to the clustering activity of duck flocks, the consequences of long-term RD farming on rice growth at different scales are still unknown. Here, we studied RD farming using several different treatments (CK: conventional rice farming; RD1: 667 m2 ; RD2: 2000 m2 ; and RD3: 3333 m2 ). RESULTS: The results demonstrated that the maximum tillers, effective spikes, dry matter accumulation, and lodging index of rice under RD farming were significantly decreased by 17.9%, 9.8%, 14.8%, and 17.8%, respectively, which ultimately caused a significant decrease in yield of 10.6%. However, RD farming significantly increased root oxidation activity and the ear-bearing tiller rate of rice by 25.5% and 11.1%, respectively, and improved yield stability. For different scales of RD farming, the lodging resistance index of RD1 was significantly lower than that of RD2 and RD3 by 10.0% and 15.2%, respectively, whereas the root oxidation activity and dry matter accumulation of RD2 were significantly higher than those of RD1 and RD3 by 11.1%, 4.7%, 8.6%, and 5.1%, respectively. For rice yield, there was no significant difference among the different scales. CONCLUSION: This long-term experiment helped elucidate the complicated effects of RD farming at different scales on the growth and yield of rice. It is also critical to consider the economic advantages of different scales of RD farming to assess the impact of this system more thoroughly. © 2023 Society of Chemical Industry.

Development of a Novel Real-Time Quantitative PCR Method for Detection of Ilyonectria robusta, the Predominant Species Causing Ginseng Rusty Root Rot.

Rusty root rot is the most destructive soilborne disease of ginseng caused by pathogenic Ilyonectria spp., predominantly Ilyonectria robusta, in China. However, there remains no effective strategy to control the disease. Current control of the disease requires that soil and ginseng seeds and seedlings infected with I. robusta are avoided during planting. Therefore, rapid and accurate detection of I. robusta would be indispensable in disease control programs. A one-step polymerase chain reaction (PCR) and quantitative real-time PCR (qPCR) assay was developed to detect I. robusta in ginseng seeds, roots, and soil. The species-specific primers HIS H3-F and HIS H3-R, designed based on a partial histone gene sequence of I. robusta, yielded a 268-bp product using the optimized PCR and qPCR protocol. DNA of I. robusta was detected by qPCR in all diseased soil and ginseng roots and seeds resulting from artificial inoculation and sampled from natural fields. I. robusta was detected at an abundance of 1.42 fg/µl at 12 h postinoculation and 191.31 fg/µl at 7 days postinoculation in ginseng roots that showed disease symptoms. In naturally infected soil sampled from ginseng fields, pathogen abundances ranging from 13.23 to 503.39 fg/µl were detected, which were 2.04 to 11.01 times higher than those in ginseng roots. The pathogen was first detected and was more abundant on the surface of the ginseng seed coat compared with that in the seed kernel. This study provides a high-efficiency detection technique for early diagnosis of I. robusta and real-time disease prevention and control strategies.

Amino Acid Substitutions at P1 Position Change the Inhibitory Activity and Specificity of Protease Inhibitors BmSPI38 and BmSPI39 from Bombyx mori.

It was found that silkworm serine protease inhibitors BmSPI38 and BmSPI39 were very different from typical TIL-type protease inhibitors in sequence, structure, and activity. BmSPI38 and BmSPI39 with unique structure and activity may be good models for studying the relationship between the structure and function of small-molecule TIL-type protease inhibitors. In this study, site-directed saturation mutagenesis at the P1 position was conducted to investigate the effect of P1 sites on the inhibitory activity and specificity of BmSPI38 and BmSPI39. In-gel activity staining and protease inhibition experiments confirmed that BmSPI38 and BmSPI39 could strongly inhibit elastase activity. Almost all mutant proteins of BmSPI38 and BmSPI39 retained the inhibitory activities against subtilisin and elastase, but the replacement of P1 residues greatly affected their intrinsic inhibitory activities. Overall, the substitution of Gly54 in BmSPI38 and Ala56 in BmSPI39 with Gln, Ser, or Thr was able to significantly enhance their inhibitory activities against subtilisin and elastase. However, replacing P1 residues in BmSPI38 and BmSPI39 with Ile, Trp, Pro, or Val could seriously weaken their inhibitory activity against subtilisin and elastase. The replacement of P1 residues with Arg or Lys not only reduced the intrinsic activities of BmSPI38 and BmSPI39, but also resulted in the acquisition of stronger trypsin inhibitory activities and weaker chymotrypsin inhibitory activities. The activity staining results showed that BmSPI38(G54K), BmSPI39(A56R), and BmSPI39(A56K) had extremely high acid-base and thermal stability. In conclusion, this study not only confirmed that BmSPI38 and BmSPI39 had strong elastase inhibitory activity, but also confirmed that P1 residue replacement could change their activity and inhibitory specificity. This not only provides a new perspective and idea for the exploitation and utilization of BmSPI38 and BmSPI39 in biomedicine and pest control, but also provides a basis or reference for the activity and specificity modification of TIL-type protease inhibitors.

Flexible assembly of the PEDOT: PSS/ exfoliated ß-Ga2O3 microwire hybrid heterojunction for high-performance self-powered solar-blind photodetector.

Motivated by the goals of fabricating highly reliable, high performance, and cost-efficient self-powered photodetector (PD) for numerous scientific research and civil fields, an organic-inorganic hybrid solar-blind ultraviolet (UV) PD based on PEDOT: PSS/exfoliated ß-Ga2O3 microwire heterojunction was fabricated by a flexible and cost-effective assembly method. Benefiting from the heterojunction constructed by the highly crystalline ß-Ga2O3 and the excellent hole transport layer PEDOT: PSS, the device presents a high responsivity of 39.8 mA/W at 250 nm and a sharp cut-off edge at 280 nm without any power supply. Additionally, the ultra-high normalized photo-to-dark current ratio (> 104 mW-1cm2) under reverse bias and the superior detectivity of 2.4×1012 Jones at zero bias demonstrate the excellent detection capabilities. Furthermore, the hybrid PD exhibits a rapid rise time (several milliseconds) and high rejection ratio (R250/R365: 5.8 × 103), which further highlights its good spectral selectivity for solar-blind UV. The prominent performance is mainly ascribed to the efficient separation of the photogenerated carriers by the large built-in electric field of the advanced heterojunction. This flexible assembly strategy for solar-blind UV PD combines the advantages of high efficiency, low cost and high performance, providing more potential for PD investigation and application in the future.

Unexpected Parabolic Temperature Dependency of CH4 Emissions from Rice Paddies.

Global warming is expected to affect methane (CH4) emissions from rice paddies, one of the largest human-induced sources of this potent greenhouse gas. However, the large variability in warming impacts on CH4 emissions makes it difficult to extrapolate the experimental results over large regions. Here, we show, through meta-analysis and multi-site warming experiments using the free air temperature increase facility, that warming stimulates CH4 emissions most strongly at background air temperatures during the flooded stage of ∼26 °C, with smaller responses of CH4 emissions to warming at lower and higher temperatures. This pattern can be explained by divergent warming responses of plant growth, methanogens, and methanotrophs. The effects of warming on rice biomass decreased with the background air temperature. Warming increased the abundance of methanogens more strongly at the medium air temperature site than the low and high air temperature sites. In contrast, the effects of warming on the abundance of methanotrophs were similar across the three temperature sites. We estimate that 1 °C warming will increase CH4 emissions from paddies in China by 12.6%─substantially higher than the estimates obtained from leading ecosystem models. Our findings challenge model assumptions and suggest that the estimates of future paddy CH4 emissions need to consider both plant and microbial responses to warming.

A Novel Fuzzy Controller for Visible-Light Camera Using RBF-ANN: Enhanced Positioning and Autofocusing.

To obtain high-precision for focal length fitting and improve the visible-light camera autofocusing speed, simultaneously, the backlash caused by gear gaps is eliminated. We propose an improved RBF (Radical Basis Function) adaptive neural network (ANN) FUZZY PID (Proportional Integral Derivative) position closed-loop control algorithm to achieve the precise positioning of zoom and focus lens groups. Thus, the Levenberg-Marquardt iterative algorithm is used to fit the focal length, and the improved area search algorithm is applied to achieve autofocusing and eliminate backlash. In this paper, we initially adopt an improved RBF ANN fuzzy PID control algorithm in the position closed-loop in the visible-light camera position and velocity double closed-loop control system. Second, a similar triangle method is used to calibrate the focal length of the visible-light camera system, and the Levenberg-Marquardt iterative algorithm is used to fit the relation of the zoom potentiometer code values and the focal length to achieve the zoom position closed-loop control. Finally, the improved area search algorithm is used to achieve fast autofocusing and acquire clear images. The experimental results show that the ITAE (integrated time and absolute error) performance index of the improved RBF ANN fuzzy PID control algorithm is improved by more than two orders of magnitude as compared with the traditional fuzzy PID control algorithm, and the settling time is 6.4 s faster than that of the traditional fuzzy PID control. Then, the Levenberg-Marquardt iterative algorithm has a fast convergence speed, and the fitting precision is high. The quintic polynomial fitting results are basically consistent with the sixth-degree polynomial. The fitting accuracy is much better than that of the quadratic polynomial and exponential. Autofocusing requires less than 2 s and is improved by more than double that of the traditional method. The improved area search algorithm can quickly obtain clear images and solve the backlash problem.

Full wafer scale electroluminescence properties of AlGaN-based deep ultraviolet LEDs with different well widths.

Deep ultraviolet (DUV) LEDs have great potential in sterilization, water, air purification, and other fields. In this work, DUV LED wafers with different quantum well (QW) widths were grown by metal-organic chemical vapor deposition. It is found that the light output power (LOP) and peak wavelength of all chips are not only related to the QW thickness but also affected by warpage. For the first time, to the best of our knowledge, a positive correlation between the LOP and peak wavelength of DUV LED chips on the same wafer was observed, which is very important for improving the yield of DUV LEDs and reducing costs. Furthermore, the influence of QW thickness on the external quantum efficiency (EQE) of DUV LED has also been investigated. As the thickness of the QW increases, the exciton localization effect decreases and the quantum confinement Stark effect increases. Consequently, DUV LED wafers with a QW thickness of 2 nm have the highest EQE and yield. These findings not only help to improve the efficiency of DUV LEDs but also provide new insights for evaluating the performance of DUV LED wafers.

Electronic excitation in graphene under single-particle irradiation.

Single-particle irradiation is a typical condition in space applications, which could be detrimental for electronic devices through processes such as single-event upset or latch-up. For functional devices made of few-atom-thick monolayers that are entirely exposed to the environment, the irradiation effects could be manifested through localized or delocalized electronic excitation, in addition to lattice defect creation. In this work, we explore the single-H irradiation effects on bare or coated graphene monolayers. Real-time time-dependent density functional theory-based first-principles calculation results elucidate the evolution of charge densities in the composite system, showing notable charge excitation but negligible charge deposition. A hexagonal boron nitride coating layer does not protect graphene from these processes. Principal component analysis demonstrates the dominance of localized excitation accompanied by nuclear motion, bond distortion and vibration, as well as a minor contribution from delocalized plasmonic excitation. The significance of coupled electron-ion dynamics in modulating the irradiation processes is identified from comparative studies on the spatial and temporal patterns of excitation for unconstrained and constrained lattices. The stopping power or energy deposition is also calculated, quantifying the dissipative nature of charge density excitation. This study offers fundamental understandings of the single-particle irradiation effects on optoelectronic devices constructed from low-dimensional materials, and inspires unconventional techniques to excite the electrons and ions in a controllable way.

Redox-responsive glycosylated combretastatin A-4 derivative as novel tubulin polymerization inhibitor for glioma and drug delivery.

Combretastatin A-4 (CA4), a tubulin inhibitor, binds to the colchicine site of tubulin, inhibits tubulin polymerization, and leads to the apoptosis of tumor cells. However, the poor hydrophilicity and blood-brain barrier (BBB) penetration ability of CA4 hampers its application in the treatment of glioma. In this study, a novel combretastatin A-4 derivative (CA4D) was designed and developed, which was further conjugated with glucose via disulfide-bond-bridged (CA4D-SS-Glu) to enhance the BBB penetration capacity. The obtained CA4D-SS-Glu conjugate displayed a suitable water partition coefficient and the superior ability across BBB in vitro and in vivo. In addition, the CA4D-SS-Glu exhibited rapid redox-responsive drug release in the presence of glutathione, enhanced in vitro cytotoxicity, and cell apoptosis. Our data further confirmed that CA4D-SS-Glu inhibited proliferation, and restrained migration via affecting microtubule stabilization. Additionally, the conjugate also showed the highest antiproliferative and antitumor action on glioma in vivo as compared to CA4D and CA4. Taken together, the novel CA4D-SS-Glu conjugate possess improved physicochemical property and BBB penetration ability, reduction triggered release of CA4D, and efficient antiproliferative activity. These results provided a novel and effective entry to the treatment of glioma.

The mental health of neurological doctors and nurses in Hunan Province, China during the initial stages of the COVID-19 outbreak.

BACKGROUND: Neurological symptoms are increasingly being noted among COVID-19 patients. Currently, there is little data on the mental health of neurological healthcare workers. The aim of this study was to identify the prevalence and influencing factors on anxiety and depression in neurological healthcare workers in Hunan Province, China during the early stage of the Coronavirus Disease 2019 (COVID-19) outbreak. METHODS: An online cross-sectional study was conducted among neurological doctors and nurses in early February 2020 in Hunan Province. Symptoms of anxiety and depression were assessed by the Chinese version of the Self-Rating Anxiety Scale (SAS) (defined as a total score ≥ 50) and Self-Rating Depression Scale (SDS) (defined as a total score ≥ 53). The prevalences of probable anxiety and depression were compared between different groups, and multivariate logistic regression analysis was used to understand the independent influencing factors on anxiety and depression. RESULTS: The prevalence of probable anxiety and depression in neurological nurses (20.3 and 30.2%, respectively) was higher than that in doctors (12.6 and 20.2%, respectively). Female healthcare workers (18.4%) had a higher proportion of anxiety than males (10.8%). Probable anxiety and depression were more prevalent among nurses, younger workers (≤ 40 years), and medical staff with junior titles. Logistic regression analysis showed that a shortage of protective equipment was independently associated with probable anxiety (OR = 1.980, 95% CI: 1.241-3.160, P = 0.004), while young age was a risk factor for probable depression (OR = 2.293, 95% CI: 1.137-4.623, P = 0.020) among neurological healthcare workers. CONCLUSIONS: Probable anxiety and depression were more prevalent among neurological nurses than doctors in Hunan Province. The shortage of protective equipment led to probable anxiety, and young age led to probable depression in healthcare workers in neurology departments, which merits attention during the battle against COVID-19.

Advantages of AlGaN-based deep-ultraviolet light-emitting diodes with an Al-composition graded quantum barrier.

AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) still suffer from poor quantum efficiency and low optical power. In this work, we proposed a DUV LED structure that includes five unique AlxGa1-xN quantum barriers (QBs); Each QB has a linear-increment of Al composition by 0.03 along the growth direction, unlike those commonly used flat QBs in conventional LEDs. As a result, the electron and hole concentration in the active region was considerably increased, attributing to the success of the electron blocking effect and enhanced hole injection efficiency. Importantly, the optical power was remarkably improved by 65.83% at the injection current of 60 mA. After in-depth device optimization, we found that a relatively thinner graded QB layer could further boost the LED performance because of the increased carrier concentrations and enhanced electron and hole wave function overlap in the QW, triggering a much higher radiative recombination efficiency. Hence, the proposed graded QBs, which have a continuous increment of Al composition along the growth direction, provide us with an effective solution to boost light output power in the pursuit of high-performance DUV emitters.

Optical polarization characteristics and light extraction behavior of deep-ultraviolet LED flip-chip with full-spatial omnidirectional reflector system.

Optical polarization characteristics and light extraction behavior of deep-ultraviolet (DUV) light-emitting diode (LED) flip-chip with full-spatial omnidirectional reflector (FSODR) have been investigated. FSODR is fabricated to be simultaneously covered on the whole flip-chip, except the sapphire surface. It is found that the FSODR greatly enhance both transverse-electric (TE) and transverse-magnetic (TM) mode light extraction at every space angle, resulting in total enhancement of 73.1% and 79.8%, respectively. Moreover, the four individual ODR structures separated from FSODR, which are covered on the surface of n-AlGaN, the interface of p-GaN/p-AlGaN, the sidewall of mesa and the sidewall of n-AlGaN/AlN, respectively, show considerably different optical polarization characteristics and extraction behaviors between each other. The achievements of FSODR cannot be obtained by any separated ODR, and all of the individual ODRs can contribute to the FSODR. Especially, the synergy effect of TM extraction behavior obviously exists in FSODR. As a result, the light extraction efficiency (LEE) enhancement of FSODR is approximately 60% at a high current density of 140A/cm2. This study is significant for understanding and modulating the extraction behavior of polarized light to realize high efficiency AlGaN-based DUV LEDs.

Ultraviolet polarized light emitting and detecting dual-functioning device based on nonpolar n-ZnO/i-ZnO/p-AlGaN heterojunction.

We report on the demonstration of a 386 nm light emission and detection dual-functioning device based on nonpolar a-plane n-ZnO/i-ZnO/p-Al0.1Ga0.9N heterojunction under both forward and reverse bias. The electroluminescence intensity under reverse bias is significantly stronger than that under forward bias, facilitated by carrier tunneling when the valence band of p-AlGaN aligns with the conduction band of i-ZnO under reverse bias. Also amid reverse bias, the photodetection was observed and applied in a duplex optical communication device. Optical polarization of the light emission is studied for potential polarization-sensitive device applications. The proposed device provides an important pathway for the multifunctional devices operating in a UV spectrum.

Building a Cocrystal by Using Supramolecular Synthons for Pressure-Accelerated Heteromolecular Azide-Alkyne Cycloaddition.

Facilitated by the supramolecular synthons of carboxylic acids and amides through cooperative hydrogen-bonding and arene-perfluoroarene interactions, the azide-alkyne cycloaddition reaction between two different molecules in a cocrystal was achieved. This reaction could be accelerated by pressure using a common hydraulic press equipment with excellent regioselectivity to yield 1,4-triazole products. The absence of decarboxylation side reactions in the products in the solid state demonstrated that this strategy can provide a green synthetic route for products not directly accessible by traditional syntheses in solution.

Strain modulated nanostructure patterned AlGaN-based deep ultraviolet multiple-quantum-wells for polarization control and light extraction efficiency enhancement.

AlGaN-based deep ultraviolet (DUV) multiple-quantum-wells (MQWs) incorporating strain-modulated nanostructures are proposed, demonstrating enhanced degree of polarization (DOP) and improved light extraction efficiency (LEE). The influence of Al composition and bi-axial strains on the optical behaviors of the DUV-MQWs were carefully examined. Compared with planar DUV-MQWs, strain-modulated nanostructure patterned MQWs show three times higher photoluminescence and increased DOP from -0.43 to -0.16. Moreover, nanostructure patterned DUV-MQWs under compressive strains further illustrate higher DOP and LEE values than those under tensile strains due to more efficient diffraction of the guided modes of the transverse electric (TE) polarized light. Our work demonstrates, for the first time, that a combination of compressive in-plane strain and surface nanostructure show unambiguous advantages in facilitating TE mode emission, thus have great promises in the design and optimization of highly efficient polarized DUV optoelectronic devices.

[Inhibition effect of biocontrol bacteria NJ13 and its mixture with chemical fungicides against ginseng root rot caused by Fusarium solani].

This study was aimed to clarify the toxicity indoor and inhibition effect of biocontrol strain NJ13 and its mixture with chemical fungicides against Fusarium solani causing ginseng root rot. The method of mycelial growth rate and Sun Yunpei method were used to determine the indoor toxicity and co-toxicity coefficient of strain NJ13 and their mixture with chemical pesticides against F. solani. The dual culture assay method,mixed culture method and microscopic observation were used to determine the sporulation and germination of spores and mycelial growth and morphological change of hyphae of F. solani treated by strain NJ13. The results of toxicity indoor showed that strain NJ13 had the best inhibitory effect on pathogen,and its EC_(50) value was 0. 071 mg·L~(-1). It was all synergistic for antifungal effect that strain NJ13 was mixed with propiconazole and difenoconazole respectively with a range from 1 ∶4 to 4 ∶1( volume ratio). Both of optimal ratios were 1 ∶1,and the co-toxicity coefficients were 848. 70 and 859. 73,respectively. The strain NJ13 could inhibit the sporulation,germination and mycelial growth of F. solani. The biocontrol strain NJ13 had an inhibition effect on F. solani,and the optimal antifungal ratio of strain NJ13 mixed with propiconazole and difenoconazole was obtained.