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Author

Yihua Hu

Bio: Yihua Hu is an academic researcher from National University of Defense Technology. The author has contributed to research in topics: Extinction (optical mineralogy) & Laser. The author has an hindex of 6, co-authored 47 publications receiving 127 citations.

Papers published on a yearly basis

Papers
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Journal ArticleDOI
TL;DR: The method can be used to discriminate the bioactivity of microbes and has potential applications in identification, detection, and optical characteristics of viable and dead microbial materials.
Abstract: We present a method to show that average mass extinction coefficient of microbes evaluated via Lorenz-Mie theory can be used to discriminate between viable and dead microbes. Reflectance of viable and dead self-cultured fungal spores and mycelia were measured by the Fourier transform infrared spectroscopy. Complex refractive indices and mass extinction coefficient of viable and dead fungal spores and mycelia were obtained in terms of Kramers-Kronig (KK) relation and Lorenz-Mie theory respectively. Smoke box experimental system was built to validate the effectiveness of the method. The results show that viable and dead fungal spores and mycelia via average mass extinction coefficients can be distinguished. The method can be used to discriminate the bioactivity of microbes and has potential applications in identification, detection, and optical characteristics of viable and dead microbial materials.

16 citations

Journal ArticleDOI
TL;DR: The simulation results showed that the parameters analyzed were closely connected with the extinction performance of fungi An0429 spores, and the Monte Carlo method could well reflect the attenuation law of IR light in fungi An 0429 spore agglomerates swarms.
Abstract: In this study, the spatial structure of randomly distributed clusters of fungi An0429 spores was simulated using a cluster aggregation (CCA) model, and the single scattering parameters of fungi An0429 spores were calculated using the discrete dipole approximation (DDA) method. The transmittance of 10.6 µm infrared (IR) light in the aggregated fungi An0429 spores swarm is simulated by using the Monte Carlo method. Several parameters that affect the transmittance of 10.6 µm IR light, such as the number and radius of original fungi An0429 spores, porosity of aggregated fungi An0429 spores, and density of aggregated fungi An0429 spores of the formation aerosol area were discussed. Finally, the transmittances of microbial materials with different qualities were measured in the dynamic test platform. The simulation results showed that the parameters analyzed were closely connected with the extinction performance of fungi An0429 spores. By controlling the value of the influencing factors, the transmittance could be lower than a certain threshold to meet the requirement of attenuation in application. In addition, the experimental results showed that the Monte Carlo method could well reflect the attenuation law of IR light in fungi An0429 spore agglomerates swarms.

13 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the reflectance spectra of 12 common biomaterials and calculated their complex refractive indexes at wavelengths of approximately 0.7, 2.1, 6.1 and 9.5μm.
Abstract: Bioaerosol, an important constituent of the atmosphere, can directly affect light radiation characteristics due to absorption and scattering effects. Current research lacks a reasonable explanation for the extinction abilities of bioaerosols in a broadband. Herein, we measured the reflectance spectra of 12 common biomaterials and calculated their complex refractive indexes. The peaks of the imaginary part of the complex refractive indexes are located at wavelengths of approximately 0.7, 2.7, 6.1 and 9.5 μm. Based on photographs of the floating structures of bioaerosols, we constructed a model for calculating the extinction abilities of bioaerosols in the wavelength range of 240 nm to 14 μm . Taking AN02 spores as an example, absorption was found to account for more than 90% of the total extinction. In addition, the theoretical calculations and experimental data of transmittance corresponding to the smoke box show that bioaerosol exhibits significant broadband extinction ability from UV to IR bands, which provides new directions for the development of broadband light attenuation materials.

13 citations

Journal ArticleDOI
TL;DR: Fermentation conditions of Beauveria bassiana and Metarhizium anisopliae s.l. were optimised to increase the conidial yields that reached 11.2 mg/g and 24.5 mg/G, increases of 72% and 52% compared to the unoptimised yields, and response surface methodology combined with a Box–Behnken design was employed to enhance the harvest efficiency.
Abstract: Methods for enhancing conidial yield and for harvesting pure fungal conidia of entomopathogenic fungi were investigated. Fermentation conditions (liquid-to-solid ratio, MgSO4·7H2O, incubation temperature, inoculum sizes, KNO3 and relative humidity) of Beauveria bassiana s.l. and Metarhizium anisopliae s.l. were optimised to increase the conidial yields that reached 11.2 mg/g and 24.5 mg/g, increases of 72% and 52% compared to the unoptimised yields of 6.5 mg/g and 16.1 mg/g, respectively. Three methods were compared for harvesting pure conidia of B. bassiana: dual cyclone equipment (DCE), sieving 200 and elution with 0.02% Tween-80 suspension. DCE performed the best, giving a conidial yield of 12.6 mg/g and 1.8 × 1010 conidia·g–1. To further enhance the harvest efficiency, response surface methodology combined with a Box–Behnken design was employed, and the conidial yield of B. bassiana reached 20.9 mg/g, a total increase of 221% compared to the original conditions. Under these optimised harvest parameter...

13 citations

Journal ArticleDOI
01 Mar 2019-Optik
TL;DR: In this article, the complex refractive indices of traditional smoke materials and bio-aerosols in the 2.5-15 μm wavebands were calculated and the IR transmittances of different smoke materials in the smoke box experiment were measured to calculate their mass extinction coefficients.

12 citations


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Journal Article
TL;DR: In this paper, the adsorption and subsequent conformational changes of sonicated unilamellar vesicles on silica supports were investigated by quartz crystal microbalance with dissipation monitoring and atomic force microscopy, using mixtures of zwitterionic, negatively charged, and positively charged lipids, both in the presence and in the absence of Ca 2 + ions.
Abstract: Supported lipid bilayers (SLBs) are popular models of cell membranes with potential biotechnological applications, yet the mechanism of SLB formation is only partially understood. In this study, the adsorption and subsequent conformational changes of sonicated unilamellar vesicles on silica supports were investigated by quartz crystal microbalance with dissipation monitoring and atomic force microscopy, using mixtures of zwitterionic, negatively charged, and positively charged lipids, both in the presence and in the absence of Ca 2 + ions. Four different pathways of vesicle deposition could be distinguished. Depending on their charge, vesicles i), did not adsorb; ii), formed a stable vesicular layer; or iii), decomposed into an SLB after adsorption at high critical coverage or iv), at low coverage. Calcium was shown to enhance the tendency of SLB formation for negatively charged and zwitterionic vesicles. The role of vesicle-support, interbilayer, and intrabilayer interactions in the formation of SLBs is discussed.

507 citations

01 Apr 2009
TL;DR: By DNA analysis, pronounced differences in the relative abundance and seasonal cycles of various groups of fungi in coarse and fine particulate matter are found, with more plant pathogens in the coarse fraction and more human pathogens and allergens in the respirable fine particle fraction.
Abstract: Fungal spores can account for large proportions of air particulate matter, and they may potentially influence the hydrological cycle and climate as nuclei for water droplets and ice crystals in clouds, fog, and precipitation. Moreover, some fungi are major pathogens and allergens. The diversity of airborne fungi is, however, not well-known. By DNA analysis we found pronounced differences in the relative abundance and seasonal cycles of various groups of fungi in coarse and fine particulate matter, with more plant pathogens in the coarse fraction and more human pathogens and allergens in the respirable fine particle fraction (<3 μm). Moreover, the ratio of Basidiomycota to Ascomycota was found to be much higher than previously assumed, which might also apply to the biosphere.

364 citations

Journal ArticleDOI
TL;DR: Conidia from entomopathogenic fungi play a major role as infective units in the current market of biopesticides and the use of proper long-term conservation microbial methods aimed at preserving the phenotypic traits of the strains is analysed.
Abstract: Demand for biopesticides is growing due to the increase of areas under integrated pest management worldwide. Conidia from entomopathogenic fungi play a major role as infective units in the current market of biopesticides. Success in a massive production of fungal conidia include the use of proper long-term conservation microbial methods, aimed at preserving the phenotypic traits of the strains. The development of suitable inoculants should also be considered since that favours a rapid germination and invasiveness of the substrate in solid state cultures (SSC). After the selection of a suitable fungal strain, proven optimization approaches for SSC mainly include the combination of substrates, moisture, texturizers, aeration and moderate stress to induce conidiation. Nonetheless, during storage and upon application in open fields, conidia either as free propagules or imbibed in formulations are subjected to stress due to abiotic factors, then quality should be preserved to resist such harsh conditions. All of these topics are analysed in this report.

103 citations

Journal ArticleDOI
14 Jun 2019
TL;DR: Synthesis, functionalization, and a toxicity profile of these carbon dots are presented and the underlying mechanisms of carbon dot-based sensing and killing of microorganisms are discussed.
Abstract: Carbon dots (or carbon quantum dots) are small (less than 10 nm) and luminescent carbon nanoparticles with some form of surface passivation. As an emerging class of nanomaterials, carbon dots have found wide applications in medicine, bioimaging, sensing, electronic devices, and catalysis. In this review, we focus on the recent advancements of carbon dots for sensing and killing microorganisms, including bacteria, fungi, and viruses. Synthesis, functionalization, and a toxicity profile of these carbon dots are presented. We also discuss the underlying mechanisms of carbon dot-based sensing and killing of microorganisms.

89 citations

Journal ArticleDOI
TL;DR: A 3D path planning method for using a UAV equipped with a Light Detection and Ranging scanner for bridge inspection that integrates a Genetic Algorithm (GA) and A* algorithm to solve the Traveling Salesman Problem (TSP).

73 citations