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1.
Artigo em Inglês | MEDLINE | ID: mdl-38896475

RESUMO

Two Gram-stain-positive, aerobic, oxidase- and catalase-negative, non-motile, and short rod-shaped actinomycetes, named SYSU T00b441T and SYSU T00b490, were isolated from tidal flat sediment located in Guangdong province, PR China. The 16S rRNA gene sequence similarity, average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between SYSU T00b441T and SYSU T00b490 were 99.3, 99.5 and 97.1 %, respectively. Strains SYSU T00b441T and SYSU T00b490 exhibited the highest 16S rRNA gene sequence similarities to Actinotalea ferrariae CF 5-4T (97.1 %/98.2 %), with ANI values of 74.01/73.88 % and dDDH values of 20.5/20.4 %. In the phylogenomic tree, the two isolates were affiliated with the genus Actinotalea. The genomes of strains SYSU T00b441T and SYSU T00b490 were 3.31 and 3.34 Mb, and both had DNA G+C contents of 72.8 mol%, coding 3077 and 3085 CDSs, three and three rRNA genes, and 53 and 51 tRNAs, respectively. Growth occurred at 15-40 °C (optimum, 28-30 °C), pH 4.0-10.0 (optimum, 7.0) and in the presence of 0-7 % (w/v) NaCl (optimum, 3 %). The major fatty acids (>10  %) of strains SYSU T00b441T and SYSU T00b490 were anteiso-C15 : 0 and C16 : 0. The major respiratory quinone was identified as MK-10(H4). The polar lipids of strains SYSU T00b441T and SYSU T00b490 were diphosphatidyl glycerol, phosphatidylglycerol, phosphoglycolipid, phosphatidyl ethanolamine, two phosphatidylinositol mannosides, two glycolipids and two phospholipids. Based on these data, the two strains (SYSU T00b441T and SYSU T00b490) represent a novel species of the genus Actinotalea, for which the name Actinotalea lenta sp. nov is proposed. The type strain is SYSU T00b441T (=GDMCC 1.3827T=KCTC 49943T).


Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Ácidos Graxos , Sedimentos Geológicos , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , RNA Ribossômico 16S/genética , Ácidos Graxos/química , Sedimentos Geológicos/microbiologia , DNA Bacteriano/genética , China , Actinobacteria/isolamento & purificação , Actinobacteria/genética , Actinobacteria/classificação , Vitamina K 2/análogos & derivados , Vitamina K 2/análise , Fosfolipídeos/química
2.
Artigo em Inglês | MEDLINE | ID: mdl-39037442

RESUMO

Two Gram-stain-negative, aerobic, milk-white coloured, non-motile, short rod-shaped bacteria, designated as strains SYSU D60010T and SYSU D60012T, were isolated from sand samples collected from the Taklimakan Desert of Xinjiang Province in China. Both strains were positive for oxidase, catalase and nitrate reduction, but negative for amylase, H2S production, hydrolysis of gelatin and cellulase. Strains SYSU D60010T and SYSU D60012T grew well at 28 °C, at pH 7 and had the same NaCl tolerance range of 0-1 % (w/v). The major fatty acids (>5 %) of strains SYSU D60010T and SYSU D60012T were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), iso-C19 : 0 cyclo ω8c, C16 : 0 and iso-C18 : 1 2-OH. Q-10 was the only respiratory ubiquinone. Strains SYSU D60010T and SYSU D60012T showed high 16S rRNA gene sequence similarities to Aestuariivirga litoralis SYSU M10001T (94.2 and 94.1 %), Rhodoligotrophos jinshengii BUT-3T (92.0 and 91.9 %) and Rhodoligotrophos appendicifer 120-1T (91.8 and 91.7 %), and the genomes were 7.4 and 5.8 Mbp in size with DNA G+C contents of 62.8 and 63.0 mol%, respectively. Phylogenetic, phenotypic and chemotaxonomic characteristics indicated that these two strains represent a novel genus and two novel species within the family Aestuariivirgaceae. We propose the name Taklimakanibacter deserti gen. nov., sp. nov. for strain SYSU D60010T, representing the type strain of this species (=KCTC 52783T =NBRC 113344T) and Taklimakanibacter lacteus gen. nov., sp. nov. for strain SYSU D60012T, representing the type strain of this species (=KCTC 52785T=NBRC 113128T).


Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Clima Desértico , Ácidos Graxos , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , Microbiologia do Solo , RNA Ribossômico 16S/genética , Ácidos Graxos/química , DNA Bacteriano/genética , China , Ubiquinona/análogos & derivados , Areia/microbiologia
3.
Antonie Van Leeuwenhoek ; 117(1): 108, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-39080041

RESUMO

A novel rod-shaped bacterium, designated as strain SYSU D60015T that formed yellowish colonies was isolated from a sandy soil collected from the Kumtag Desert in Xinjiang, China. Cells were Gram-stain-negative, oxidase-positive, catalase-negative and motile with a single polar flagellum. Growth optimum occurred between 28 and 37 °C, pH 7.0 and with 0-0.5% (W/V) NaCl. The predominant cellular fatty acids (> 5%) were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c), C19:0 cyclo ω8c, C18:1 ω7c 11-methyl and C16:0. The polar lipid profile contained one phosphatidylethanolamine, one diphosphatidylglycerol, one phosphatidylglycerol, one unidentified phospholipid, three unidentified aminolipids, two unidentified aminophospholipids and seven unidentified lipids. The only respiratory quinone was ubiquinone-10. Based on 16S rRNA gene sequence phylogenetic analysis, strain SYSU D60015T was found to form a distinct linage within the family Sneathiellaceae, and had 16S rRNA gene sequence similarities of 90.8% to Taonella mepensis H1T, and 90.2% to Ferrovibrio denitrificans S3T. The genome of SYSU D60015T was 5.66 Mb in size with 68.2% of DNA G + C content. The low digital DNA-DNA hybridization (dDDH, 18.0%), average nucleotide identity (ANI, 77.5%) and amino acid identity (AAI, 56.0%) values between SYSU D60015T and Ferrovibrio terrae K5T indicated that SYSU D60015T might represent a distinct genus. Based on the phylogenetic, phenotypic, chemotaxonomic and genomic data, we propose Desertibaculum subflavum gen. nov., sp. nov. as a novel species of a new genus within the family Sneathiellaceae. The type strain is SYSU D60015T (= NBRC 112952T = CGMCC 1.16256T).


Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Clima Desértico , Ácidos Graxos , Filogenia , RNA Ribossômico 16S , Microbiologia do Solo , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , China , Ácidos Graxos/análise , Ácidos Graxos/química , Análise de Sequência de DNA , Fosfolipídeos/análise , Fosfolipídeos/química
4.
Proc Natl Acad Sci U S A ; 118(40)2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34580205

RESUMO

Southern China and Southeast Asia witnessed some of their most significant economic and social changes relevant to human land use during the Late Holocene, including the intensification and spread of rice agriculture. Despite rice growth being associated with a number of earth systems impacts, how these changes transformed tropical vegetation in this region of immense endemic biodiversity remains poorly understood. Here, we compile a pollen dataset incorporating ∼150,000 identifications and 233 pollen taxa to examine past changes in floral biodiversity, together with a compilation of records of forest decline across the region using 14 pollen records spanning lowland to mountain sites. Our results demonstrate that the rise of intensive rice agriculture from approximately 2,000 y ago led not only to extensive deforestation but also to remarkable changes of vegetation composition and a reduction in arboreal diversity. Focusing specifically on the Tertiary relic tree species, the freshwater wetland conifer Glyptostrobus (Glyptostrobus pensilis), we demonstrate how key species that had survived changing environmental conditions across millions of years shrank in the face of paddy rice farming and human disturbance.


Assuntos
Efeitos Antropogênicos , Biodiversidade , Ecologia , Plantas/classificação , Sudeste Asiático , Fósseis , Paleontologia
5.
Int J Syst Evol Microbiol ; 73(10)2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37791661

RESUMO

A Gram-stain-negative, aerobic, short rod-shaped, yellow bacterium, designated SYSU DXS3180T, was isolated from forest soil of Danxia Mountain in PR China. Growth occurred at 15-37 °C (optimum, 28-30 °C), pH 6.0-10.0 (optimum, pH 7.0-8.0) and with 0-2.0 % NaCl (optimum, 0-0.5 %, w/v). Strain SYSU DXS3180T was positive for hydrolysis of Tween 20, Tween 60, Tween 80 and starch, but negative for urease, H2S production, nitrate reduction, Tween 40 and gelatin. Phylogenetic analysis based on 16S rRNA gene and genome sequences showed that SYSU DXS3180T belonged to the family Chitinophagaceae. The closely related members were Foetidibacter luteolus YG09T (94.2 %), Limnovirga soli KCS-6T (93.9 %) and Filimonas endophytica SR 2-06T (93.7 %). The genome of strain SYSU DXS3180T was 7287640 bp with 5782 protein-coding genes, and the genomic DNA G+C content was 41.4 mol%. The main respiratory quinone was MK-7 and the major fatty acids (>10 %) were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G. The major polar lipids consisted of phosphatidylethanolamine, two unidentified aminolipids and two unidentified polar lipids. Based on the phylogenetic, phenotypic and chemotaxonomic characteristics, strain SYSU DXS3180T is proposed to represent a novel species of a novel genus named Danxiaibacter flavus gen. nov., sp. nov., within the family Chitinophagaceae. The type strain is SYSU DXS3180T (=KCTC 92895T=GDMCC 1.3825 T).


Assuntos
Ácidos Graxos , Microbiologia do Solo , Ácidos Graxos/química , Filogenia , RNA Ribossômico 16S/genética , Solo , DNA Bacteriano/genética , Composição de Bases , Técnicas de Tipagem Bacteriana , Análise de Sequência de DNA , Florestas
6.
Br J Clin Pharmacol ; 89(1): 209-221, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35939394

RESUMO

AIM: Propofol and opioids are commonly used in anaesthesia, but are highly susceptible to haemodynamic instability, thereby threatening the patient's surgical safety and prognosis. The purpose of this study was to investigate the predictors of haemodynamic instability and establish its predictive model. METHODS: A total of 150 Chinese patients undergoing thyroid or breast surgery participated in the study, with target-controlled infusion concentrations of propofol, opioids dosage, heart rate (HR), mean arterial pressure (MAP) and Narcotrend Index recorded at key points throughout the procedure. The Agena MassARRAY system was used to genotype candidate single nucleotide polymorphisms related to pharmacodynamics and pharmacokinetics of propofol and opioids. RESULTS: Among nongenetic factors, baseline HR (R = -.579, P < .001) and baseline MAP (R = -.725, P < .001) had a significant effect on the haemodynamic instability. Among genetic factors, the CT/CC genotype of GABRB1 rs4694846 (95% confidence interval [CI]: -11.309 to -3.155), AA/AG of OPRM1 rs1799971 (95%CI: 0.773 to 10.290), AA of CES2 rs8192925 (95%CI: 1.842 to 9.090) were associated with higher HR instability; the AA/GG genotype of NR1I2 rs6438550 (95%CI: 0.351 to 7.761), AA of BDNF rs2049046 (95%CI: -9.039 to -0.640) and GG of GABBR2 rs1167768 (95%CI: -10.146 to -1.740) were associated with higher MAP instability. The predictive models of HR and MAP fluctuations were developed, accounting for 45.0 and 59.2% of variations, respectively. CONCLUSION: We found that cardiovascular fundamentals and genetic variants of GABRB1, GABBR2, OPRM1, BDNF, CES2 and NR1I2 are associated with cardiovascular susceptibility, which can provide a reference for haemodynamic management in clinical anaesthesia.


Assuntos
Propofol , Humanos , Propofol/farmacocinética , Anestésicos Intravenosos/farmacocinética , Analgésicos Opioides/farmacologia , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Receptor de Pregnano X , Estudos Retrospectivos , Pressão Sanguínea , Hemodinâmica
7.
BMC Gastroenterol ; 23(1): 359, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37853349

RESUMO

BACKGROUND: Helicobacter pylori (HP) infection is associated with various diseases. Early detection can prevent the onset of illness. We constructed a nomogram to predict groups at high risk of HP infection. METHODS: Patients who underwent regular medical check-ups at hospital in Chaoshan, China from March to September 2022 were randomly allocated to the training and validation cohorts. Risk factors including basic characteristics and lifestyle habits associated with HP infection were analyzed by logistic regression analyses. The independent varieties were calculated and plotted into a nomogram. The nomogram was internally validated by receiver operating characteristic curve, calibration, and decision curve analyses (DCAs). RESULTS: Of the 945 patients, 680 were included in the training cohort and 265 in the validation cohort. 356 patients in training cohort with positive 13 C-UBT results served as the infected group, and 324 without infection were the control group. The multivariate regression analyses showed that the risk factors for HP infection included alcohol consumption (OR = 1.29, 95%CI = 0.78-2.13, P = 0.03), family history of gastric disease (OR = 4.35, 95%CI = 1.47-12.84, P = 0.01), living with an HP-positive individual (OR = 18.09, 95%CI = 10.29-31.82, P < 0.0001), drinking hot tea (OR = 1.58, 95%CI = 1.05-2.48, P = 0.04), and infection status of co-drinkers unknown (OR = 2.29, 95%CI = 1.04-5.06, P = 0.04). However, drinking tea > 3 times per day (OR = 0.56, 95%CI = 0.33-0.95, P = 0.03), using serving chopsticks (OR = 0.30, 95%CI = 0.12-0.49, P < 0.0001) were protective factors for HP infection. The nomogram had an area under the curve (AUC) of 0.85 in the training cohort. The DCA was above the reference line within a large threshold range, indicating that the model was better. The calibration analyses showed the actual occurrence rate was basically consistent with the predicted occurrence rate. The model was validated in the validation cohort, and had a good AUC (0.80), DCA and calibration curve results. CONCLUSIONS: This nomogram, which incorporates basic characteristics and lifestyle habits, is an efficient model for predicting those at high risk of HP infection in the Chaoshan region.


Assuntos
Infecções por Helicobacter , Helicobacter pylori , Humanos , China/epidemiologia , Infecções por Helicobacter/epidemiologia , Estilo de Vida , Nomogramas , Chá
8.
Curr Microbiol ; 80(5): 142, 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36930356

RESUMO

An actinobacterium, designated as SYSU T00001T, was isolated from a tidal flat sediment sample from Guangdong province, China. Cells were Gram-stain-positive, aerobic, motile and short rod-shaped. Colonies on marine agar 2216 were smooth, yellow-pigmented, and circular with low convexity. The isolate was able to grow at the temperature range 4-37 °C (optimum 30 °C), at pH 4.0-10.0 (optimum 7.0) and in the presence of 0-10% (w/v) NaCl. The major menaquinones were MK-11 and MK-10. The cell wall contained alanine, glutamic acid, lysine and ornithine. The major fatty acids were C19:0 cyclo ω8c (35.7%) and anteiso C15:0 (26.0%). The polar lipids consisted of one diphosphatidyl glycerol, one unidentified glycolipid and one unknown lipid. Whole genome sequencing of strain SYSU T00001T revealed 2,837,702 bp with a DNA G + C content of 67.8%. Phylogenetic analyses clearly demonstrated that strain SYSU T00001T belonged to the genus Salinibacterium, and the highest 16S rRNA gene similarity to Salinibacterium hongtaonis 194T (97.8%). The ANI and dDDH values of strain SYSU T00001T relative to Salinibacterium hongtaonis 194T were 74.5% and 19.5%, respectively. According to our data, strain SYSU T00001T represents a novel species of the genus Salinibacterium, for which the name Salinibacterium sedimenticola sp. nov. is proposed, the type strain is SYSU T00001T (= GDMCC 1.3283T = KCTC 49758T).


Assuntos
Actinomycetales , Gammaproteobacteria , Fosfolipídeos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Actinomycetales/genética , Ácidos Graxos/química , Gammaproteobacteria/genética , Vitamina K 2/química
9.
Proc Natl Acad Sci U S A ; 117(39): 24138-24143, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32929013

RESUMO

Rice agriculture is the foundation of Asian civilizations south of the Yangtze River. Although rice history is well documented for its lower Yangtze homeland area, the early southward expansion of paddy rice farming is poorly known. Our study investigates this process using a compilation of paleoenvironmental proxies from coastal sediment cores from southeast China to Thailand and Island Southeast Asia. We propose that a shortage of land suitable for paddy fields, caused by marine transgression, constrained rice agriculture during the mid-Holocene. Rapid expansion of coastal plains, particularly in deltaic basins, over the past three millennia has coincided with increases in land suitable for rice cultivation. Our study also helps explain the past population movements of rice farmers.


Assuntos
Agricultura/história , Meio Ambiente , Fósseis , Oryza , Ásia Oriental , Geografia , História Antiga , Pólen
10.
Hum Mol Genet ; 29(15): 2471-2480, 2020 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-32592472

RESUMO

Charcot-Marie-Tooth (CMT) disease is the most common inherited peripheral neuropathy and shows clinical and genetic heterogeneity. Mutations in C1orf194 encoding a Ca2+ regulator in neurons and Schwann cells have been reported previously by us to cause CMT disease. In here, we further investigated the function and pathogenic mechanism of C1or194 by generating C1orf194 knockout (KO) mice. Homozygous mutants of C1orf194 mice exhibited incomplete embryonic lethality, characterized by differentiation abnormalities and stillbirth on embryonic days 7.5-15.5. Heterozygous and surviving homozygous C1orf194 KO mice developed motor and sensory defects at the age of 4 months. Electrophysiologic recordings showed decreased compound muscle action potential and motor nerve conduction velocity in the sciatic nerve of C1orf194-deficient mice as a pathologic feature of dominant intermediate-type CMT. Transmission electron microscopy analysis revealed demyelination and axonal atrophy in the sciatic nerve as well as swelling and loss of mitochondrial matrix and other abnormalities in axons and Schwann cells. A histopathologic examination showed a loss of motor neurons in the anterior horn of the spinal cord and muscle atrophy. Shorter internodal length between nodes of Ranvier and Schmidt-Lanterman incisures was detected in the sciatic nerve of affected animals. These results indicate that C1orf194 KO mice can serve as an animal model of CMT with a severe dominant intermediate CMT phenotype that can be used to investigate the molecular mechanisms of the disease and evaluate the efficacy of therapeutic strategies.


Assuntos
Doença de Charcot-Marie-Tooth/genética , Deficiências do Desenvolvimento/genética , Fases de Leitura Aberta/genética , Natimorto/genética , Animais , Axônios/metabolismo , Doença de Charcot-Marie-Tooth/mortalidade , Doença de Charcot-Marie-Tooth/patologia , Deficiências do Desenvolvimento/patologia , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Knockout , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Mutação/genética , Bainha de Mielina/genética , Fenótipo , Células de Schwann/metabolismo , Células de Schwann/patologia , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia
11.
Small ; 17(51): e2102641, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34553484

RESUMO

Silicon monoxide (SiO) has been explored and confirmed as a promising anode material of lithium-ion batteries. Compared with pure silicon, SiO possesses a more stable microstructure which makes better comprehensive electrochemical properties. However, the lithiation mechanism remains in dispute, and problems such as poor cyclability, unsatisfactory electrical conductivity, and low initial Coulombic efficiency (ICE) need to be addressed. Additionally, more attention needs to be paid on the internal relationship between electrochemical performances and structures. In this review, the different preparation processes, the derived microstructure of the SiOx , the corresponding lithiation mechanism, and electrochemical properties are summarized. Researches about disproportionation reaction which is regarded as a key point and other modifications are systematically introduced. Closely linked with structure, the advantages and disadvantages of various SiOx anode materials are summarized and analyzed, and the possible directions toward the practical applications of SiOx anode material are presented. In a word, from the preparation and reaction mechanism of the material to the modifications and future development, a complete and systematical review on SiOx anode is presented.

12.
Langmuir ; 35(10): 3694-3700, 2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30776313

RESUMO

Platinum-decorated graphene aerogel microspheres were fabricated through a combined electrospraying, freeze-casting, and solvothermal process. Platinum nanoparticles with a narrow size distribution are evenly anchored on the graphene aerogel microspheres without agglomeration benefitting from the distinct center-diverging microchannel structure of the graphene aerogel microspheres, which results in the as-prepared catalysts presenting excellent electrocatalytic performance including high electrocatalytic activity and high poison tolerance toward methanol electro-oxidation, showing great potential for direct methanol fuel cell anode catalysts. In particular, the platinum-decorated graphene aerogel microspheres exhibit an extremely high mass activity of 1098.9 mA mg-1 toward methanol oxidation as well as excellent antipoisoning ability, which are dramatically enhanced compared with Pt particles dispersed on graphene oxide and commercial carbon black supports.

13.
AAPS PharmSciTech ; 18(5): 1564-1571, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27604884

RESUMO

The aim of this study was to prepare aptamer-modified liposomes loaded with gadolinium (Gd) to enhance the effective diagnosis for tumor by MRI. A modified GBI-10 (GBI-10m) was used to prepare targeted liposomes (GmLs). Liposomes with GBI-10 aptamer (GLs) and without aptamer (non-targeted liposomes (NLs)) were also prepared as controls. The particle size and zeta potential of GmLs, GLs, and NLs were all assayed. A clinical 3.0 T MR scanner was employed to assess the imaging efficiency and measure the longitudinal relaxivity (r 1) of the above liposomes. Confocal laser scanning microscopy and flow cytometry were used to analyze and compare the targeting effects of GmLs, GLs, and NLs to MDA-MB-435s cells at 37°C. The particle size of the prepared liposomes was scattered at 100-200 nm, and their values of r 1 were ∼4 mM-1 s-1. The images of confocal laser scanning microscopy showed that GmLs in the cytoplasm were significantly more than GLs and both GmLs and GLs were more than NLs. The fluorescence intensity of GmLs was increased by about two times than that of GLs and three times than that of NLs by flow cytometry. Therefore, the GmLs in this initial study were suggested to be a potential MRI contrast agent at 37°C for diagnosing tumors with the protein of tenascin-C over-expressed.


Assuntos
Gadolínio/farmacologia , Imageamento por Ressonância Magnética/métodos , Neoplasias/diagnóstico , Animais , Aptâmeros de Nucleotídeos/farmacologia , Meios de Contraste/farmacologia , Citometria de Fluxo/métodos , Humanos , Lipossomos , Microscopia Confocal/métodos , Tamanho da Partícula
14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(9): 2971-7, 2016 Sep.
Artigo em Zh | MEDLINE | ID: mdl-30085489

RESUMO

This paper focuses on the study on continuous XRF (X-Ray Fluorescence) scanning elements of a 39 m core from Fuzhou Basin. The XRF scanning result is used to recognize the different sedimentary environment before the discussion of the element variation of different deposit in transitional zone between land and ocean. There are five sedimentary facies in the study area from the late Pleistocene: lacustrine-fluvial-estuary (mud tidal flat)-mixed tidal flat-fluvial. The XRF result from the 5 sedimentary stages shows that the high concentration of Co, Fe, Ti, Si are controlled largely by grain size. The average element intensity of layers with similar grain size indicates that Ca, Ti, Mn, Fe and Co from the marine (tidal flat) deposit is 3~10 times bigger than those from terrestrial (fluvial) deposit, with higher content of Si coinciding with terrestrial deposit. It is indicated that except grain size, the deposit environment is an important factor for element concentration. In this study, Ca, Ti, Mn, Fe and Co are relatively better indicator elements for marine sediments while Si is good and K, Rb and Sr have some indication for terrestrial sediments. The study result shows XRF continuous scanning can help to identify the subtle variation of elements, as to the determination of the sediment facies. Thus, XRF scanning is an important supplement to sediment facies identification. This study also provides an application example of XRF in a typical transitional zone between land and ocean.

15.
Beijing Da Xue Xue Bao Yi Xue Ban ; 46(5): 744-80, 2014 Oct 18.
Artigo em Zh | MEDLINE | ID: mdl-25331398

RESUMO

OBJECTIVE: To develop and investigate the properties of MRI-traceable Eudragit-E liquid embolic agent (MR-E). METHODS: Polyethylene glycol-modified superparamagnetic iron oxides (PEG-SPIO) was synthesized by chemical co-precipitation method. MR-E was prepared by mixing PEG-SPIO and Eudragit-E liquid embolic agent homogeneously. An in vitro MR phantom study was carried out to measure MR traceability of MR-E and to determine the concentration of PEG-SPIO for further studies. The microcatheter deliverability and sol-gel transition process of MR-E were investigated. MR-E was injected into the kidney of a Japanese white big ear rabbit via an angiographic microcatheter, and detected by MRI. RESULTS: A PEG-SPIO concentration of 2 g/L was considered to be suitable for further studies. MR-E was injected through the microcatheter without any difficulty. MR-E instantly solidified on release into saline. Then 0.2 mL of MR-E effectively embolized distal renal arteries, and MR-E could be detected by MRI in the embolized kidney. CONCLUSION: MR-E seems to be a promising MRI-traceable liquid embolic agent.


Assuntos
Dextranos/farmacologia , Embolização Terapêutica , Metilmetacrilatos/farmacologia , Artéria Renal , Animais , Rim/efeitos dos fármacos , Imageamento por Ressonância Magnética , Nanopartículas de Magnetita , Imagens de Fantasmas , Coelhos
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 310: 123890, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38237500

RESUMO

Eu3+ is not only a major red-emitting activator, but also an excellent spectral probe ion. This work reports the Eu3+-sites and luminescence in the cation-deficient perovskite tungstates, A-site deficient SrLa2(Mg2W2)O12 [Sr1/2□1/2La(MgW)O6] and B-site deficient Sr2La2(MgW2)O12 [SrLa(Mg1/2□1/2W)O6]. The 7F0→5D0 excitation spectra of Eu3+ activators in two lattices were measured via pulsed dye laser. In SrLa2(Mg2W2)O12:Eu3+, there is only one 7F0→5D0 transition, which could be related to the Eu3+ center on La3+ sites; while, two 7F0→5D0 transitions in Sr2La2(MgW2)O12 indicate Eu3+ ions occupy Sr2+ in addition to La3+, resulting in the luminescent centers related to heterovalent substitution defects. The different Eu3+ sites make two phosphors exhibit different red luminescence properties. SrLa2(Mg2W2)O12:Eu3+ shows higher luminescent efficiency and thermal quenching due to its regular distribution of the activators resulting in lower dispersion losses of the energy transfer. The experimental results show that rare earth ions occupy different crystallographic positions in A-site and B-site deficient perovskite oxides, and this microstructure can be important for the corresponding luminescent properties.

17.
Artigo em Inglês | MEDLINE | ID: mdl-39388323

RESUMO

Our understanding of the temporal dynamics of the Earth's surface has been significantly advanced by deep vision models, which often require a massive amount of labeled multi-temporal images for training. However, collecting, preprocessing, and annotating multi-temporal remote sensing images at scale is non-trivial since it is expensive and knowledge-intensive. In this paper, we present scalable multi-temporal change data generators based on generative models, which are cheap and automatic, alleviating these data problems. Our main idea is to simulate a stochastic change process over time. We describe the stochastic change process as a probabilistic graphical model, namely the generative probabilistic change model (GPCM), which factorizes the complex simulation problem into two more tractable sub-problems, i.e., condition-level change event simulation and image-level semantic change synthesis. To solve these two problems, we present Changen2, a GPCM implemented with a resolution-scalable diffusion transformer which can generate time series of remote sensing images and corresponding semantic and change labels from labeled and even unlabeled single-temporal images. Changen2 is a "generative change foundation model" that can be trained at scale via self-supervision, and is capable of producing change supervisory signals from unlabeled single-temporal images. Unlike existing "foundation models", our generative change foundation model synthesizes change data to train task-specific foundation models for change detection. The resulting model possesses inherent zero-shot change detection capabilities and excellent transferability. Comprehensive experiments suggest Changen2 has superior spatiotemporal scalability in data generation, e.g., Changen2 model trained on 256 2 pixel single-temporal images can yield time series of any length and resolutions of 1,024 2 pixels. Changen2 pre-trained models exhibit superior zero-shot performance (narrowing the performance gap to 3% on LEVIR-CD and approximately 10% on both S2Looking and SECOND, compared to fully supervised counterpart) and transferability across multiple types of change tasks, including ordinary and off-nadir building change, land-use/land-cover change, and disaster assessment. The model and datasets are available at https://github.com/Z-Zheng/pytorch-change-models.

18.
Adv Mater ; 36(9): e2307701, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38061761

RESUMO

Efficient wide bandgap (WBG) perovskite solar cells (PSCs) are essential for fully maximizing the potential of tandem solar cells. However, these cells currently face challenges such as high photovoltage losses and the presence of phase segregation, which impede the attainment of their expected efficiency and stability. Herein, the root cause of halide segregation is investigated, uncovering a close association with the presence of locally aggregated lead iodide (PbI2 ), particularly at the perovskite/C60 interface. Kelvin-probe atomic force microscopy results indicate that the remaining PbI2 at the interface leads to potential electrical differences between the domain surface and boundaries, which drives the formation of halide segregation. By reacting the surface PbI2 residue with ethanediamine dihydroiodide (EDAI2 ) at proper temperature, it is possible to effectively mitigate the phase segregation. By applying this surface reaction strategy in WBG inverted cells, a notable improvement of ≈100 mV is achieved in photovoltage over a wide range of WBG cells (1.67-1.78 eV), resulting in a champion efficiency of 23.1% (certified 22.95%) for 1.67 eV cells and 19.7% (certified 18.81%) for 1.75 eV cells. Furthermore, efficiency of 26.1% is demonstrated in a monolithic all-perovskite tandem cell.

19.
Microsyst Nanoeng ; 10(1): 132, 2024 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-39327437

RESUMO

Owing to the controllable growth and large-area synthesis for high-density integration, interest in employing atomically thin two-dimensional (2D) transition-metal dichalcogenides (TMDCs) for synaptic transistors is increasing. In particular, substitutional doping of 2D materials allows flexible modulation of material physical properties, facilitating precise control in defect engineering for eventual synaptic plasticity. In this study, to increase the switch ratio of synaptic transistors, we selectively performed experiments on WS2 and introduced niobium (Nb) atoms to serve as the channel material. The Nb atoms were substitutionally doped at the W sites, forming a uniform distribution across the entire flakes. The synaptic transistor devices exhibited an improved switch ratio of 103, 100 times larger than that of devices prepared with undoped WS2. The Nb atoms in WS2 play crucial roles in trapping and detrapping electrons. The modulation of channel conductivity achieved through the gate effectively simulates synaptic potentiation, inhibition, and repetitive learning processes. The Nb-WS2 synaptic transistor achieves 92.30% recognition accuracy on the Modified National Institute of Standards and Technology (MNIST) handwritten digit dataset after 125 training iterations. This study's contribution extends to a pragmatic and accessible atomic doping methodology, elucidating the strategies underlying doping techniques for channel materials in synaptic transistors.

20.
Adv Sci (Weinh) ; 11(17): e2309020, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38368272

RESUMO

The requirement for cryogenic supramolecular self-assembly of amphiphiles in subzero environments is a challenging topic. Here, the self-assembly of lamellar lyotropic liquid crystals (LLCs) are presented to a subzero temperature of -70 °C. These lamellar nanostructures are assembled from specifically tailored ultra-long-chain surfactant stearyl diethanolamine (SDA) in water/glycerol binary solvent. As the temperature falls below zero, LLCs with a liquid-crystalline Lα phase, a tilted Lß phase, and a new folded configuration are obtained consecutively. A comprehensive experimental and computational study is performed to uncover the precise microstructure and formation mechanism. Both the ultra-long alkyl chain and head group of SDA play a crucial role in the formation of lamellar nanostructures. SDA head group is prone to forming hydrogen bonds with water, rather than glycerol. Glycerol cannot penetrate the lipid layer, which mixes with water arranging outside of the lipid bilayer, providing an ideal anti-freezing environment for SDA self-assembly. Based on these nanostructures and the ultra-low freezing point of the system, a series of novel cryogenic materials are created with potential applications in extremely cold environments. These findings would contribute to enriching the theory and research methodology of supramolecular self-assembly in extreme conditions and to developing novel anti-freezing materials.

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