• Journal of the Optical Society of Korea
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• 제20권2호
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• pp.269-275
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• 2016

This study has investigated the feasibility of 980-nm low-energy pulsed near-infrared laser stimulation to evoke auditory responses, as well as the effects of radiant exposure and pulse duration on auditory responses. In the experiments, a hole was drilled in the basal turn of the cochlea in guinea pigs. An optical fiber with a 980-nm pulsed infrared laser was inserted into the hole, orientating the spiral ganglion cells in the cochlea. To model deafness, the tympanic membrane was mechanically damaged. Acoustically evoked compound action potentials (ACAPs) were recorded before and after deafness, and optically evoked compound action potentials (OCAPs) were recorded after deafness. Similar spatial selectivity between optical and acoustical stimulation was found. In addition, OCAP amplitudes increased with radiant exposure, indicating a photothermal mechanism induced by optical stimulation. Furthermore, at a fixed radiant exposure, OCAP amplitudes decreased as pulse duration increased, suggesting that optical stimulation might be governed by the time duration over which the energy is delivered. Thus, the current experiments have demonstrated that a 980-nm pulsed near-infrared laser with low energy can evoke auditory neural responses similar to those evoked by acoustical stimulation. This approach could be used to develop optical cochlear implants.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제1권1호
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• pp.58-67
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• 2020

Terrestrial ecosystems influence climate change via their climate regulation function, which is manifested within the carbon, water, and energy circulation between the atmosphere and surface. However, it has been challenging to quantify the climate regulation of terrestrial ecosystems and identify its regional distribution, which provides useful information for establishing regional climate-mitigation plans as well as facilitates better understanding of the interactions between the climate and land processes. In this study, a land surface model (LSM) that represents the land-atmosphere interactions and plant phenological variations was introduced to assess the contributions of terrestrial ecosystems to atmospheric warming or cooling effects over East Asia over the last half century. Three main climate-regulating components were simulated: net radiation flux, carbon exchange, and moisture flux at the surface. Then, the contribution of each component to the atmospheric warming or cooling (negative or positive feedback to the atmosphere, respectively) was investigated. The results showed that the terrestrial ecosystem over the Siberian region has shown a relatively large increase in positive feedback due to the enhancement of biogeochemical processes, indicating an offset effect to delay global warming. Meanwhile, the Gobi Desert shows different regional variations: increase in positive feedback in its southern part but increase in negative one in its eastern part, which implies the eastward movements of desert areas. As such, even though the LSM has limitations, this model approach to quantify the climate regulation is useful to extract the relevant characteristics in its spatio-temporal variations.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제1권1호
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• pp.22-30
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• 2020

Many areas of vegetation in the British uplands have reduced species diversity as a result of sheep overgrazing. It has been suggested that abandonment or re-wilding strategies might be used to reverse this. A likely first step would be the removal or reduction of grazing livestock from upland areas, with a presumption that this would lead to a recovery in species richness. However, we do not know if this would work, or the timescales involved. One of the important areas where more knowledge is needed is information on the size and composition of soil seedbanks as regeneration from zseed is a likely pathway of recovery. Here, we compared seedbanks in both grazed and ungrazed plots in five experiments at Moor House NNR in the northern Pennines; these sheep grazing exclusion experiments were started 52 and 63/64 years ago. Soil samples (n=10) were collected from both grazed and ungrazed plots in each experiment, and seed emergence counted in glasshouse trials. We detected only seeds of common species and very few dicotyledonous species. This suggests that the soil seedbank is unlikely to be a reliable source of the less common species for ecological restoration in these upland communities, suggesting an extinction debt. Therefore, seed addition and the creation of suitable safe-sites for germination may be needed in conjunction with grazing controls to allow the establishment of plants that will increase the species richness of the vegetation. However, this interventionist restoration approach remains to be tested.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2556-2566
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• 2023

A first-principle approach within the framework of density functional theory was employed to study the effect of vacancy defects and fission products (FPs) doping on the mechanical, electronic, and thermodynamic properties of uranium monocarbide (UC). Firstly, the calculated vacancy formation energies confirm that the C vacancy is more stable than the U vacancy. The solution energies indicate that FPs prefer to occupying in U site rather than in C site. Zr, Mo, Th, and Pu atoms tend to directly replace U atom and dissolve into the UC lattice. Besides, the results of the mechanical properties show that U vacancy reduces the compressive and deformation resistance of UC while C vacancy has little effect. The doping of all FPs except He has a repairing effect on the mechanical properties of U_1-xC. In addition, significant modifications are observed in the phonon dispersion curves and partial phonon density of states (PhDOS) of UC_1-x, Zr_xU_1-xC, Mo_xU_1-xC, and Rh_xU_1-xC, including narrow frequency gaps and overlapping phonon modes, which increase the phonon scattering and lead to deterioration of thermal expansion coefficient (α_V) and heat capacity (C_p) of UC predicted by the quasi harmonic approximation (QHA) method.

• 항공우주정책ㆍ법학회지
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• 제32권1호
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• pp.385-417
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• 2017

Insurances of space activities are divided into satellite insurance, astronaut insurance and third party liability insurance. Against the background of the rapid development of space commercialization, especially the increasing participation of private entities in space affairs, the present international and domestic mechanisms of space insurance are challenged. As a space-faring state which is in the process of developing space businesses, the regulations of space insurance in China are deserved to be discussed. Satellites insurance is at present well-developed, the "pre-launch", "launch" and "in-orbit" phases of satellites are all possible to be insured by related companies. China created the CAIA in 1997 to provide insurance for Chinese satellites. However, with more private entities start to involve in space as well as satellite industry, the regime established under the framework of CAIA is necessary to be modified, and the mechanism relating to space insurance brokers should be promoted. The astronauts are recognized as the envoy of humankind, and relevant international regulations are made to provide assistance to them in emergency circumstances. From the domestic perspective, astronauts will be fully insured. China creates a particular type of insurance for astronauts. However, once space tourism becomes a business, the insurance of the tourist will be demanded to be created. In order to promote China's space tourism, it is recommended to take the "Astronaut Group Insurance" as an optional model to space tourists, if the tourists are customers of a governmental-owned space company. Once private involvement of providing orbital/suborbital tourism service becomes a reality, new rules are required. Getting a third party liability insurance is deemed as an indispensable precondition for an applicant to get a launch permission. Domestic space laws will include provisions for the third party liability insurance. China's "Interim Measures" of 2002 realizes the importance of third party liability insurance and requires the permit holder to get it before entering the launching site. This regulation is different from the practices of other states. Concerning that China is the sponsor of APSCO, for the purpose of promoting commercial space cooperation, a harmonized approach to domestic law is recommended to be found.

• Molecular & Cellular Toxicology
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• 제2권4호
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• pp.236-243
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• 2006

Microarray analysis of gene expression has become a powerful approach for exploring the biological effects of drugs, particularly at the stage of toxicology and safety assessment. Acetaminophen (APAP) has been known to induce necrosis in liver, but the molecular mechanism involved has not been fully understood. In this study, we investigated gene expression changes of APAP using microarray technology. APAP was orally administered with a single dose of 50 mg/kg or 500 mg/kg into ICR mice and the animals were sacrificed at 6, 24 and 72 h of APAP administration. Serum biochemical markers for liver toxicity were measured to estimate the maximal toxic time and hepatic gene expression was assessed using high-density oligonucleotide microarrays capable of determining the expression profile of >30,000 well-substantiated mouse genes. Significant alterations in gene expression were noted in the liver of APAP-administered mice. The most notable changes in APAP-administered mice were the expression of genes involved in apoptosis, cell cycle, and calcium signaling pathway, cystein metabolism, glutatione metabolism, and MAPK pathway. The majority of the genes upregulated included insulin-like growth factor binding protein 1, heme oxygenase 1, metallothionein 1, S100 calcium binding protein, caspase 4, and P21. The upregulation of apoptosis and cell cycle-related genes were paralleled to response to APAP. Most of the affected gene expressions were returned to control levels after 72 hr. In conclusion, we identified potential hepatotoxicity makers, and these expressions profiling lead to a better understanding of the molecular basis of APAP-induced hapatotoxicity.