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Assessing the Economic Value of Improvement in Water Quality and Aquatic Ecosystem Services Resulting from Ecological Stream Restoration in South Korea
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作者 Hyun No Kim Hwanhee Ryu 《Journal of Environmental & Earth Sciences》 2025年第1期471-484,共14页
Urbanization and environmental degradation have led to significant declines in water quality and aquatic ecosystem health,highlighting the urgent need for effective restoration efforts.This study applies an integrated... Urbanization and environmental degradation have led to significant declines in water quality and aquatic ecosystem health,highlighting the urgent need for effective restoration efforts.This study applies an integrated analysis approach to estimate the economic value and benefits of improvements in water quality and aquatic ecosystem services resulting from the Ecological Stream Restoration Project.Using survey data analyzed through the choice experiment(CE)method,we assessed respondents’preferences for various ecosystem services,including water-friendly services,ecological functions,water-level control,and water-quality purification.Three empirical analysis models—the Conditional Logit Model(CLM),Nested Logit Model(NL),and Error Component Logit Model(ECL)—were applied,with the ECL model identified as the most suitable for this study.From the physical impact assessment,we derived compensating variations to estimate the annual economic benefits of the project.The estimated annual economic value of water quality improvement due to the Anyangcheon Ecological Stream Restoration Project ranged from approximately KRW 10.54 billion to KRW 21.44 billion,while the economic value of aquatic ecosystem improvement was estimated to range from KRW 6.05 billion to KRW 12.30 billion annually.This study provides analytic framework that can inform future ecological restoration projects and sustainable water management policies. 展开更多
关键词 Ecological Stream Restoration Non-Market Valuation Choice Experiment Ecosystem Services Integrated Environmental And Economic Analysis
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Integrating Environmental Value into Strategic Environmental Assessment:An Empirical Application to a Multipurpose Rural Water Development Project in South Korea
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作者 Hyun No Kim Hwanhee Ryu 《Journal of Environmental & Earth Sciences》 2025年第7期285-298,共14页
This study examines the empirical feasibility of quantitatively integrating environmental value information into Strategic Environmental Assessment(SEA).An analytical framework was established to incorporate environme... This study examines the empirical feasibility of quantitatively integrating environmental value information into Strategic Environmental Assessment(SEA).An analytical framework was established to incorporate environmental cost estimates into the SEA process by utilizing ecosystem service unit values provided by the Environmental Valuation Information System(EVIS),a national platform developed to support the evaluation of policies and projects.The framework was applied to a case study involving a multipurpose rural water development project in South Korea.Ecosystem service losses resulting from the project were quantified using biophysical indicators,such as vegetation biomass,forest area,and hydrological functions,and subsequently monetized through the application of the market price method,replacement cost method,and contingent valuation method.The total annual environmental cost was estimated to be approximately KRW 56.18 billion,with the majority attributable to losses in forest conservation and climate regulation services.These findings demonstrate that quantified environmental data can serve as a robust basis for alternative comparison and site evaluation within SEA.The study provides empirical evidence supporting the advancement of SEA from a predominantly procedural tool focused on environmental protection to a more comprehensive sustainability assessment framework that integrates environmental,economic,and social considerations.Furthermore,the results suggest that EVIS-based quantitative information holds potential for broader application in other national evaluation systems,such as preliminary feasibility studies and regulatory impact assessments. 展开更多
关键词 Environmental Valuation Information System(EVIS) Strategic Environmental Assessment(SEA) Sustainability Assessment Ecosystem Services Environmental Decision-Making
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Efficient electrocatalytic oxidation of glycerol toward formic acid over well-defined nickel nanoclusters capped by ligands
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作者 Dan Yang Xiang Cui +8 位作者 Zhou Xu Qian Yan Yating Wu Chunmei Zhou Yihu Dai Xiaoyue Wan Yuguang Jin Leonid M.Kustov Yanhui Yang 《Chinese Journal of Catalysis》 2025年第9期185-197,共13页
The electrocatalytic oxidation of glycerol toward formic acid is one of the most promising pathways for transformation and utilization of glycerol.Herein,a series of well-defined Ni_(n)(SR)_(2n) nanoclusters(n=4,5,6;d... The electrocatalytic oxidation of glycerol toward formic acid is one of the most promising pathways for transformation and utilization of glycerol.Herein,a series of well-defined Ni_(n)(SR)_(2n) nanoclusters(n=4,5,6;denoted as Ni NCs)were prepared for the electrocatalytic glycerol oxidation toward formic acid,in which Ni_(6)-PET-50CV afforded the most excellent electrocatalytic performance with a high formic acid selectivity of 93% and a high glycerol conversion of 86%.This was attributed to the lowest charge transfer impedance and the most rapid reaction kinetics.Combined electrochemical measurements and X-ray absorption fine structure measurements revealed that the structures of Ni NCs remained intact after CV scanning pretreatment and electrocatalysis via forming the Ni–O bond.Additionally,the kinetic studies and in-situ Fourier transformed infrared suggested a sequential oxidation mechanism,in which the main reaction steps of glycerol→glyceraldehyde→glyceric acid were very rapid to produce a high selectivity of formic acid even though the low glycerol conversion.This work presents an opportunity to study Ni NCs for the efficient electrocatalytic oxidation of biomass-derived polyhydroxyl platform molecules to produce value-added carboxylic acids. 展开更多
关键词 Nickel nanocluster Well-defined structure Electrocatalysis Glycerol oxidation Formic acid
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Green perovskite CsPbBr_(3)light-emitting electrochemical cells with distributed Si nanowires-based electrodes for flexible applications
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作者 Viktoriia Mastalieva Anastasiya Yakubova +17 位作者 Maria Baeva Vladimir Neplokh Dmitry M.Mitin Vladimir Fedorov Alexander Goltaev Alexey Mozharov Fedor Kochetkov Andrei S.Toikka Ramazan Kenesbay Ekaterina Vyacheslavova Alexander Vorobyev Kristina Novikova Dmitry Krasnikov Jianjun Tian Albert G.Nasibulin Alexander Gudovskikh Sergey Makarov Ivan Mukhin 《Journal of Semiconductors》 2025年第7期117-126,共10页
The emergence of cesium lead halide perovskite materials stable at air opened new prospects for the optoelectronic industry.In this work we present an approach to fabricating a flexible green perovskite light-emitting... The emergence of cesium lead halide perovskite materials stable at air opened new prospects for the optoelectronic industry.In this work we present an approach to fabricating a flexible green perovskite light-emitting electrochemical cell(PeLEC)with a CsPbBr_(3)perovskite active layer using a highly-ordered silicon nanowire(Si NW)array as a distributed electrode integrated within a thin polydimethylsiloxane film(PDMS).Numerical simulations reveal that Si NWs-based distributed electrode aids the improvement of carrier injection into the perovskite layer with an increased thickness and,therefore,the enhancement of light-emitting performance.The X-ray diffraction study shows that the perovskite layer synthesized on the PDMS membrane with Si NWs has a similar crystal structure to the ones synthesized on planar Si wafers.We perform a comparative analysis of the light-emitting devices’properties fabricated on rigid silicon substrates and flexible Si NW-based membranes released from substrates.Due to possible potential barriers in a flexible PeLEC between the bottom electrode(made of a network of single-walled carbon nanotube film)and Si NWs,the electroluminescence performance and Ⅰ-V properties of flexible devices deteriorated compared to rigid devices.The developed PeLECs pave the way for further development of inorganic flexible uniformly light-emitting devices with improved properties. 展开更多
关键词 silicon nanowires PEROVSKITE CsPbBr_(3)thin film SILICON PeLEC
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Dynamic evolution of olfactory receptor genes in the Turkey Vulture and Black Vulture
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作者 Joni E.Wright Edward L.Braun +1 位作者 J.Gordon Burleigh Rebecca T.Kimball 《Avian Research》 2025年第4期754-763,共10页
Olfactory receptors(ORs),the largest vertebrate multigene family,exhibit wide copy number variation among taxa,ranging from~100 to 4000.The ecological importance of smell has been suggested to positively correlate wit... Olfactory receptors(ORs),the largest vertebrate multigene family,exhibit wide copy number variation among taxa,ranging from~100 to 4000.The ecological importance of smell has been suggested to positively correlate with OR gene number,though debate exists on whether the number of total ORs,functional ORs,or the percentage of pseudogenes matters most.While olfaction has been poorly studied in most birds,Turkey Vultures(Cathartes aura)demonstrate keen olfactory ability,capable of foraging using smell alone.In contrast,Black Vultures(Coragyps atratus)have been thought to primarily use vision to locate food.Comparison of the OR genes in these two New World vultures presents an opportunity to examine the dynamics of OR evolution in related avian species that may differ in olfactory abilities.Using a PCR and cloning approach with degenerate primers,we sampled the OR subgenome in Turkey and Black Vultures,as well as Red-tailed Hawks(Buteo jamaicensis)and the distantly related Chicken(Gallus gallus),neither of which are thought to use olfaction extensively.Our results indicate that Turkey Vultures have many more OR genes than Red-tailed Hawks or chickens.Surprisingly,Black Vultures had an intermediate number of OR genes.The number of OR genes we estimated in the Turkey Vulture was much greater than previously reported in studies that used short-read sequencing.Additionally,we found that OR genes from New World vultures and Red-tailed Hawks form clades that were distinct from the clade that included most chicken OR genes,indicating that chickens share few OR orthologs with New World vultures or hawks.As previously observed in other animal groups,pseudogenes appeared throughout all clades and their percentage varied among taxa.These findings suggest the OR gene family is highly dynamic,changing rapidly over evolutionary time,and that taxa may have distinct suites of ORs in their genomes. 展开更多
关键词 Avian olfaction Black Vulture Olfactory subgenome PSEUDOGENES Turkey Vulture
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Synergistic Anti-Lung Cancer and Immunomodulatory Effects of Combined Extracts from Acanthopanax sessiliflorus,Phragmites communis,and Pinus densiflora
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作者 Anjali Kariyarath Valappil Reshmi Akter +7 位作者 Muhammad Awais Dong Uk Yang Daehyo Jung Li Ling Eun Kim Kyu Hyeong Yoon Yoon Ok Lee Deok Chun Yang 《BIOCELL》 2025年第9期1771-1795,共25页
Objectives:The phytochemical investigation of traditional herbal medicines holds significant promise for modern drug discovery,particularly in cancer therapy.This study aimed to evaluate the cytotoxicity,apoptosis ind... Objectives:The phytochemical investigation of traditional herbal medicines holds significant promise for modern drug discovery,particularly in cancer therapy.This study aimed to evaluate the cytotoxicity,apoptosis induction,and immune-modulatory activities of extracts from three herbal medicines with historical use in traditional medicine—Acanthopanax sessiliflorus,Phragmites communis,and Pinus densiflora,as well as their combined extract(GMAS 01/COM),on human lung cancer cells(A549)and normal cell lines,including murine macrophages(RAW 264.7)and human keratinocytes(HaCaT).Methods:Plant extracts were prepared using aqueous extraction,sonication,and rotary evaporation.The total phenolic and flavonoid contents were quantified using the Folin-Ciocalteu and AlCl3 colorimetric methods,respectively.Antioxidant potential was evaluated via 2,2-Diphenyl-1-picrylhydrazyl(DPPH)scavenging and reducing power assays.Cytotoxicity was assessed using an MTT assay,while reactive oxygen species(ROS)generation was quantified using a 2′,7′-Dichlorodihydrofluorescein diacetate(DCFH-DA)assay.Anticancer properties,including colony formation inhibition and migration suppression,were examined using colony formation and wound healing assays.The expression of apoptotic and inflammatory mediators was analysed through qPCR.Results:GMAS 01 selectively induced apoptosis in A549 cells without cytotoxic effects on RAW264.7 and HaCaT cells.Mechanistically,it elevated intracellular ROS and activated the intrinsic mitochondrial apoptotic pathway,evidenced by p53 upregulation,increased Bax,and decreased Bcl-2 expression.GMAS 01 also significantly inhibited colony formation and migration in A549 cells.In RAW264.7 cells,it reduced nitric oxide(NO)production and downregulated iNOS,COX-2,IL-6,and IL-8,indicating strong immunomodulatory activity.Conclusion:GMAS 01 exhibits potent antioxidant,anti-inflammatory,and anticancer effects,likely mediated through ROS-induced mitochondrial apoptosis.However,mechanistic interpretations are limited by the absence of protein-level validation and pathway inhibition studies.Upcoming studies should aim to verify the underlying mechanisms and evaluate their potential for real-world application. 展开更多
关键词 ANTIOXIDANTS ROS lung cancer immune modulation Acanthopanax sessiliflorus Phragmites communis Pinus densiflora apoptosis
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Characterization of bright betatron radiation generated by direct laser acceleration of electrons in plasma of near critical density 被引量:1
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作者 J.Cikhardt M.Gyrdymov +9 位作者 S.Zähter P.Tavana M.M.Günther N.Bukharskii N.Borisenko J.Jacoby X.F.Shen A.Pukhov N.E.Andreev O.N.Rosmej 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第2期26-35,共10页
Directed x-rays produced in the interaction of sub-picosecond laser pulses of moderate relativistic intensity with plasma of near-critical density are investigated. Synchrotron-like (betatron) radiation occurs in the ... Directed x-rays produced in the interaction of sub-picosecond laser pulses of moderate relativistic intensity with plasma of near-critical density are investigated. Synchrotron-like (betatron) radiation occurs in the process of direct laser acceleration (DLA) of electrons in a relativisticlaser channel when the electrons undergo transverse betatron oscillations in self-generated quasi-static electric and magnetic fields. In anexperiment at the PHELIX laser system, high-current directed beams of DLA electrons with a mean energy ten times higher than the ponderomotive potential and maximum energy up to 100 MeV were measured at 10^(19) W/cm^(2)laser intensity. The spectrum of directed x-raysin the range of 5–60 keV was evaluated using two sets of Ross filters placed at 0°and 10°to the laser pulse propagation axis. The differential x-ray absorption method allowed for absolute measurements of the angular-dependent photon fluence. We report 10^(13) photons/sr withenergies >5 keV measured at 0°to the laser axis and a brilliance of 10^(21) photons s^(−1) mm^(−2) mrad−2(0.1%BW)−1. The angular distributionof the emission has an FWHM of 14°–16°. Thanks to the ultra-high photon fluence, point-like radiation source, and ultra-short emissiontime, DLA-based keV backlighters are promising for various applications in high-energy-density research with kilojoule petawatt-class laserfacilities. 展开更多
关键词 laser ACCELERATION CRITICAL
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Model-based interpretation of bottomhole pressure records during matrix treatments in layered formations
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作者 Igor Reznikov Dmitry Abdrazakov Dimitry Chuprakov 《Petroleum Science》 SCIE EI CAS CSCD 2024年第5期3587-3611,共25页
During injection treatments, bottomhole pressure measurements may significantly mismatch modeling results. We devise a computationally effective technique for interpretation of fluid injection in a wellbore interval w... During injection treatments, bottomhole pressure measurements may significantly mismatch modeling results. We devise a computationally effective technique for interpretation of fluid injection in a wellbore interval with multiple geological layers based on the bottomhole pressure measurements. The permeability, porosity and compressibility in each layer are initially setup, while the skin factor and partitioning of injected fluids among the zones during the injection are found as a solution of the problem. The problem takes into account Darcy flow and chemical interactions between the injected acids, diverter fluids and reservoir rock typical in modern matrix acidizing treatments. Using the synchronously recorded injection rate and bottomhole pressure, we evaluate skin factor changes in each layer and actual fluid placement into the reservoir during different pumping jobs: matrix acidizing, water control, sand control, scale squeezes and water flooding. The model is validated by comparison with a simulator used in industry. It gives opportunity to estimate efficiency of a matrix treatment job, role of every injection stage, and control fluid delivery to each layer in real time. The presented interpretation technique significantly improves accuracy of matrix treatments analysis by coupling the hydrodynamic model with records of pressure and injection rate during the treatment. 展开更多
关键词 Matrix treatment Inverse problem Forward problem Skin factor INTERPRETATION
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Graphene-calcium carbonate coating to improve the degradation resistance and mechanical integrity of a biodegradable implant 被引量:1
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作者 Lokesh Choudhary Parama Chakraborty Banerjee +5 位作者 R.K.Singh Raman Derrek E.Lobo Christopher D.Easton Mainak Majumder Frank Witte Jörg F.Löffler 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第1期394-404,共11页
Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body environment.This necessitates the synthesis of a suitable coating that may improve ... Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body environment.This necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical integrity.In this study,an AZ91 magnesium alloy,as a representative for a biodegradable Mg implant material,was modified with a thin reduced graphene oxide(RGO)-calcium carbonate(CaCO_(3))composite coating.Detailed analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity,and thus has the potential to greatly extend the related application field. 展开更多
关键词 Graphene coating Biodegradable implant HYDROXYAPATITE Corrosion Magnesium alloy
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Coal ash resources and potential for rare earth element production in the United States
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作者 Robert C.Reedy Bridget R.Scanlon +4 位作者 Davin A.Bagdonas James C.Hower Dennis James J.Richard Kyle Kristine Uhlman 《International Journal of Coal Science & Technology》 CSCD 2024年第5期151-161,共11页
The renewable energy industry is heavily reliant on rare earth elements,underscoring the need to develop resources and production.The objective of this work was to estimate coal ash resources and potential for extract... The renewable energy industry is heavily reliant on rare earth elements,underscoring the need to develop resources and production.The objective of this work was to estimate coal ash resources and potential for extraction of rare earth elements using data for the US.Data on spatiotemporal variability in coal ash resources and disposition were compiled from various federal databases and rare earth elements levels in ash were compiled from the literature.Results show that~52 gigatons(Gt)of coal were produced in the US(1950-2021).Power plants account for most of the coal use,particularly since 1980.Coal ash(5.3 Gt)represents a mean of 10%of coal by weight,ranging from 6%for subbituminous to 14%for lignite.About 70% of coal ash is potentially accessible for rare earth element extraction(1985-2021)and was disposed in landfills and ponds with the remaining coal ash used onsite or sold.Median values of total rare earth elements are much higher in ashes derived from the Appalachian Basin(median 431 mg/kg)than in the Illinois(282 mg/kg)or Powder River basins(264 mg/kg).Considering the market value of rare earth oxides,potentially accessible ash volumes,and percent rare earth element extraction(30%Appalachian and Illinois Basins;70% Powder River Basin)results in an estimated$8.4 billion value.This study provides fundamental information on accessible coal ash resources in the US,linkages to coal sources,and preliminary estimates of rare earth element levels for future development within the US. 展开更多
关键词 Coal combustion byproducts Coal ash Fly ash:Bottom ash Rare earth elements Resource evaluation
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Fragipan Soil Changes with Growth of Annual Ryegrass and Festulolium with Surface Applied Amendments
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作者 Lloyd Murdock Anastasios Karathanasis +2 位作者 Dottie Call Dana Lee Dinnes Amitava Chatterjee 《Open Journal of Soil Science》 2024年第12期765-777,共13页
A greenhouse experiment was conducted involving complete/intact 100 cm cores of a fragipan soil. The cores were maintained in moist conditions throughout the experiment as annual ryegrass (Lolium multiflorum) or festu... A greenhouse experiment was conducted involving complete/intact 100 cm cores of a fragipan soil. The cores were maintained in moist conditions throughout the experiment as annual ryegrass (Lolium multiflorum) or festulolium (Lolium spp and Fescue spp hybrid) were grown with and without additional surface applied amendments, including NaF, NaNO3, NaCl, and KCl. The results suggest a significant effect of annual ryegrass and festulolium on fragipan horizon degradation after 24 months. Annual ryegrass and festulolium were found to effectively change the structure of the fragipan horizon when planted on the soil surface and roots grew through the upper soil profile and penetrated into the fragipan. The fragipan structural change (degradation) appeared to increase with each planting sequence, particularly with soybean crop rotations. Sodium nitrate added to the soil surface with the growth of annual ryegrass resulted in a significant synergistic effect for degrading the fragipan horizon. The other amendments were not as effective in causing additional fragipan degradation. 展开更多
关键词 Fragipan Soil Horizons Plant Root Restriction Degradation of Compacted Sections Effect of Ryegrass and Festulolium Root Penetration Effect of NaF NaNO3 NaCl KCl Surface Applied Amendments Soybean-Ryegrass and Soybean-Festulolium Rotations
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Fragipan Horizon Changes Using Annual Ryegrass and Other Admendments
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作者 Lloyd Murdock Anastasios Karathanasis +2 位作者 Dottie Call Dana L. Dinnes Amitava Chatterjee 《Open Journal of Soil Science》 2024年第6期388-397,共10页
A greenhouse experiment was conducted involving intact fragipan soil cores of 50 cm thickness after removing the topsoil horizons. The cores were maintained in moist condition throughout the experiment and received se... A greenhouse experiment was conducted involving intact fragipan soil cores of 50 cm thickness after removing the topsoil horizons. The cores were maintained in moist condition throughout the experiment and received several treatments with various amendments for different periods ranging from 9 to 17 months. The amendments included annual ryegrass or Festulolium residues, powder limestone and various humate compounds alone or in combination with the grass residues. The results suggested a significant effect of ryegrass and Festulolium in reducing penetration resistance into the top 10 cm of the fragipan within 9 - 17 months, particularly when used in combination with certain humate materials such as Leonardite. Apparently, this is the result of the release of certain soluble organic compounds from the plant residues or the humate amendments that increase the solubility of Si and Al associated with the fragipan brittleness, thus decreasing the density of the compacted fragipan material. 展开更多
关键词 Fragipan Fragipan Horizon Fragipan Soils Changing the Fragipan Annual Ryegrass Changes Fragipan Festulolium Changes Fragipan Amendments That Change the Fragipan
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Molecular profiles and long-term outcomes of Thai children with hepatic glycogen storage disease in Thailand
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作者 Jaravee Vanduangden Rungnapa Ittiwut +4 位作者 Chupong Ittiwut Teerasak Phewplung Anapat Sanpavat Palittiya Sintusek Kanya Suphapeetiporn 《World Journal of Clinical Pediatrics》 2024年第4期25-36,共12页
BACKGROUND Thus far,genetic analysis of patients clinically diagnosed with glycogen storage diseases(GSDs)in Thailand has not been reported.AIM To evaluate the clinical and biochemical profiles,molecular analysis and ... BACKGROUND Thus far,genetic analysis of patients clinically diagnosed with glycogen storage diseases(GSDs)in Thailand has not been reported.AIM To evaluate the clinical and biochemical profiles,molecular analysis and long-term outcomes of Thai children diagnosed with hepatic GSD.METHODS Children aged<18 years diagnosed with hepatic GSD and followed up at King Chulalongkorn Memorial Hospital were recruited.Whole-exome sequencing(WES)was performed to identify the causative gene variants.Medical records were assessed.RESULTS All eight children with histopathologically confirmed diagnosis were classified by WES into subtypes Ia(n=1),III(n=3),VI(n=3),and IX(n=1).A total number of 10 variants were identified including G6PC(n=1),AGL(n=4),PYGL(n=5),and PHKA2(n=1).AGL had two novel variants.The clinical manifestations were hepatomegaly(n=8),doll-like facies(n=3),wasting(n=2),and stunting(n=5).All patients showed hypoglycemia,transaminitis,and dyslipidemia.The mainstay of treatment was cornstarch supplementation and high-protein and low-lactosefructose diet.After a median follow-up time of 9.59 years,height turned to normal for age in 3/5 patients and none had malnutrition.Liver enzymes,blood sugar,and lipid profiles improved in all.CONCLUSION Hepatomegaly,transaminitis,and hypoglycemia are the hallmarks of GSD confirmed by liver histopathology.Molecular analysis can confirm the diagnosis or classify the subtype that might benefit from personalized treatment,prognosis,and long-term care. 展开更多
关键词 Storage disease HYPOGLYCEMIA PEDIATRIC Whole exome sequencing Novel variants Thailand
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塔里木盆地寒武纪—奥陶纪优质烃源岩沉积与古环境变化的关系:碳氧同位素新证据 被引量:72
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作者 张水昌 R L WANG +3 位作者 金之钧 张宝民 王大锐 边立曾 《地质学报》 EI CAS CSCD 北大核心 2006年第3期459-466,共8页
对塔里木盆地东部塔东2井上震旦统和寒武系—奥陶系样品进行TOC和碳、氧同位素及微量元素分析,发现该井稳定碳、氧同位素值在寒武系—中奥陶统发生明显变化,该层还赋存高有机质丰度烃源岩,其TOC值的高低可反映当时的生物产率和埋藏率。... 对塔里木盆地东部塔东2井上震旦统和寒武系—奥陶系样品进行TOC和碳、氧同位素及微量元素分析,发现该井稳定碳、氧同位素值在寒武系—中奥陶统发生明显变化,该层还赋存高有机质丰度烃源岩,其TOC值的高低可反映当时的生物产率和埋藏率。碳和氧同位素值在寒武系/上震旦统分界处正向漂移,说明正好在进入寒武纪前气候明显变冷,海平面下降。接着,下寒武统底部以碳和氧同位素值的快速负向漂移为标志,表明古气候迅速变暖和海平面大幅度上升,烃源岩TOC值也达到全井柱最高值。古气候显著波动、海平面最高及其频繁变化和沉积物高TOC是早寒武世的显著特征;而晚寒武世—早奥陶世,同位素正向漂移,暗示海平面下降,沉积物TOC也随之下降并降至最低;到了早奥陶世末,即早、中奥陶世的过渡时期,同位素又开始负向漂移,TOC又开始升高;中奥陶世,同位素强烈负向漂移,TOC又升至新高。稳定碳、氧同位素值的变化及其所指示的古气候与海平面变化,以及与TOC的响应关系,指示冰期、冰后期之交,古气候迅速变暖和海平面大幅度上升有利于烃源岩发育;同时暗示,δ13C、δ18O与生烃母质生物的有机生产率、有机埋藏率之间存在某种内在联系。即高TOC含量反映高的有机生产率和高的有机埋藏率;而与其同步反方向变化的δ13C、δ18O则暗示海平面较高,沉积环境属远陆海域,表层水中生烃母质生物的光合作用很强。而有机质的高产率和高埋藏率,导致海水中δ12C和δ16O被大量地固定在沉积物中。这样,就使海水中相对富集13C和18O重同位素而使海水变“重”;而这种“重”海水,又导致了同时期浅水区碳酸盐沉积物的δ13C和δ18O值明显增高。 展开更多
关键词 寒武纪 奥陶纪 氧同位素 古气候 烃源岩 TOC
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蒙其古尔铀矿床砂岩型铀矿生物成矿作用探讨 被引量:6
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作者 刘俊平 邱余波 +3 位作者 周剑 文战久 Fayek M 张虎军 《科学技术与工程》 北大核心 2015年第26期115-119,共5页
蒙其古尔铀矿床是伊犁盆地南缘铀资源量最大的砂岩型铀矿床,关于该矿床的成因机理,也一直是铀矿地质学界关注的焦点。通过对该矿床含矿地层的地球化学特征、黏土矿物特征进行分析研究,以及对黄铁矿硫同位素的分析测试,认为在铀成矿过程... 蒙其古尔铀矿床是伊犁盆地南缘铀资源量最大的砂岩型铀矿床,关于该矿床的成因机理,也一直是铀矿地质学界关注的焦点。通过对该矿床含矿地层的地球化学特征、黏土矿物特征进行分析研究,以及对黄铁矿硫同位素的分析测试,认为在铀成矿过程中有还原物质的参与,而且该还原物质与生物作用有一定关系。生物作用参与成矿可能是蒙其古尔铀矿床矿体品位较高的重要原因。 展开更多
关键词 伊犁盆地 蒙其古尔铀矿床 砂岩型铀矿 生物成矿作用
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家族性肌萎缩侧索硬化症转基因鼠的繁殖和鉴定 被引量:2
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作者 黄慧 张成 +3 位作者 席静 姚晓黎 邱国光 熊符 《南方医科大学学报》 CAS CSCD 北大核心 2006年第3期258-260,265,共4页
目的建立家族性肌萎缩侧索硬化症(FALS)转基因模型鼠的繁育方法,并对其子代鼠进行基因鉴定。方法(1)以6只B6SJL SOD1G93A/+半合子雄鼠与6只B6SJLF1/J+/+雌鼠(1∶1)交配;(2)由鼠尾血提取基因组DNA,PCR扩增hmSOD1基因的片段,电泳后观察结... 目的建立家族性肌萎缩侧索硬化症(FALS)转基因模型鼠的繁育方法,并对其子代鼠进行基因鉴定。方法(1)以6只B6SJL SOD1G93A/+半合子雄鼠与6只B6SJLF1/J+/+雌鼠(1∶1)交配;(2)由鼠尾血提取基因组DNA,PCR扩增hmSOD1基因的片段,电泳后观察结果;(3)对PCR产物进行纯化测序,并通过BLAST验证。结果6对种鼠交配产鼠仔53只,存活率为98%(52/53);G93A hmSOD1阳性鼠约占44.2%(23/52);PCR扩增产物分别为内对照(IL-2):324 bp;Tg(hmSOD1):236 bp;测序证实PCR产物的基因序列和hmSOD1基因片段中的序列一致,并存在G93A突变。结论B6SJL-Tg(SOD1-G93A)1Gur/J雄鼠与B6SJLF1/J雌鼠配种能成功繁育出Tg(hmSOD1)阳性的ALS半合子子代鼠;本实验的PCR法能准确鉴定hmSOD1基因阳性鼠,并证实该转入的基因按近似孟德尔方式遗传,为ALS实验研究奠定了基础。 展开更多
关键词 肌萎缩侧索硬化症 繁殖 小鼠 转基因 基因鉴定
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人类鼻咽癌细胞株CNE2的转化基因Tx的一个Eco RI片段的核苷酸序列分析 被引量:5
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作者 胡维新 曹亚 +1 位作者 黎民敬 姚开泰 《生物化学杂志》 CSCD 1993年第3期331-336,共6页
本文运用定点克隆法并结合鸟枪法,对人类鼻咽癌细胞抹CNE2转化基因Tx中一个与转化作用有关的Eco RI片段,进行了核苷酸序列分析。此种克隆方法的运用,大大减少了DNA模板的数量,并加快了测序的进展。将序列分析结果输入美国NCI的CRAY-2型... 本文运用定点克隆法并结合鸟枪法,对人类鼻咽癌细胞抹CNE2转化基因Tx中一个与转化作用有关的Eco RI片段,进行了核苷酸序列分析。此种克隆方法的运用,大大减少了DNA模板的数量,并加快了测序的进展。将序列分析结果输入美国NCI的CRAY-2型超级电子计算机作进一步分析,以寻找基因库中的同源序列,酶切位点,开放阅读框架(ORF)。在人类DNA基因数据库中没有找到同源序列,从而证实Tx基因是一种新的人类转化基因。计算机的分析还得出了一系列有价值的结论,为进一步深入探讨这个基因在人类鼻咽癌发病学中的作用,提供了重要的资料。这是首次报道的Tx基因核苷酸序列分析结果。 展开更多
关键词 鼻咽肿瘤 转化基因 核甘酸 分析
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水井反冲洗地层三维弹塑性固结分析 被引量:1
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作者 王素玲 李杨 +1 位作者 沈新普 刘勤志 《岩土力学》 EI CAS CSCD 北大核心 2012年第10期3156-3161,共6页
注水井反冲洗工艺是抽油机井维持正常生产的重要措施之一,反冲洗压力是决定反冲洗效率的主要因素。反冲洗过程涉及到地层与套管在水压作用下的相互耦合作用,鉴于目前对洗井压力的制定以套管抗挤压强度为依据,运用ABAQUS-6.5软件,对油藏... 注水井反冲洗工艺是抽油机井维持正常生产的重要措施之一,反冲洗压力是决定反冲洗效率的主要因素。反冲洗过程涉及到地层与套管在水压作用下的相互耦合作用,鉴于目前对洗井压力的制定以套管抗挤压强度为依据,运用ABAQUS-6.5软件,对油藏岩石-套管进行了三维弹塑性固结有限元分析,建立了流-固耦合数学模型,研究了注水井反冲洗过程中套管、地层和流体的瞬态响应,实现了套管、地层和流体间的耦合作用,得到了套管应力随洗井时间的变化规律。计算结果表明,洗井地层的地应力分布状态和地层性质对洗井压力影响较大,主要受到地层弹性模量、渗透性能和地层水平地应力的影响。洗井压力的制定应综合考虑套管和地层状况,与单纯考虑套管的承载能力相比,其研究结果可为洗井工艺的制定提供更为准确的理论基础。 展开更多
关键词 地层 反冲洗 流固耦合 弹塑性 有限元
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碳化钽粉末的爆炸成形方法 被引量:1
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作者 徐磊 B.S.Majumdar +1 位作者 Darrell Marchant Lawrence Matson 《材料工程》 EI CAS CSCD 北大核心 2007年第z1期127-130,共4页
碳化钽熔点为3880℃,是地球上第二高熔点的物质.其抗腐蚀性能优越,在航空领域有广阔的应用空间.但是传统的材料加工方法,比如热压或者热等静压,会导致晶粒快速长大而得到低的断裂韧性.本文利用爆破方法来克服晶粒长大问题,得到强度和断... 碳化钽熔点为3880℃,是地球上第二高熔点的物质.其抗腐蚀性能优越,在航空领域有广阔的应用空间.但是传统的材料加工方法,比如热压或者热等静压,会导致晶粒快速长大而得到低的断裂韧性.本文利用爆破方法来克服晶粒长大问题,得到强度和断裂韧性高的碳化钽.碳化钽颗粒直径小于3μm,组成晶粒为0.5~1μm,填充到双层钢管进行爆炸处理.在钢管的底部发现碳化钽试样几乎达到理论密度,但是该区域裂纹较多,硬度测得为15 GPa,和文献报道的碳化钽理论硬度相同.在钢管的中部的试样密度为理论密度的85%,这个区域没有发现裂纹.之后的旨在提高试样密度热处理中,发现了其烧结特征发生改善.经分析是因为爆炸使碳化钽粉末的颗粒内部产生内应力,而使其扩散激活能降低的结果. 展开更多
关键词 碳化钽 爆炸成形
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大豆体细胞胚系培养及其微卫星DNA稳定性研究(简报) 被引量:2
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作者 史京花 吕慧能 +2 位作者 Daina Simmonds 盖钧镒 喻德跃 《分子细胞生物学报》 CSCD 北大核心 2006年第1期71-76,共6页
植物离体培养是植物基因操作中的重要一环.也是植物个体发育研究中基因表达研究的有益参考体系。在继代培养过程中发生的遗传变异有时会使再生植株丧失优良的性状而需加以控制和避免。为此,首先需要了解培养过程中的遗传变异情况。
关键词 体细胞胚系 微卫星DNA 大豆 再生植株 遗传变异
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