Search

Polyimide (PI) films with extremely high breakdown strength (451 kV/mm), energy density (5.2 J/cm³), and discharge efficiency (86.7%) at the room temperature are fabricated by simple solution casting method. Barium titanate (BaTiO3) nanoparticles are introduced into PI matrix, giving rise to enhanced dielectric permittivity (6.8) and low dielectric loss (0.012). Dielectric and energy storage performances of the BTO/PI nanocomposites are thoroughly investigated up to 200 °C. The breakdown strengths of both pure PI and BTO/PI nanocomposites decrease dramatically with the increase in the temperature, owing to the low thermal conductivity of PI and the consequent thermal runaway caused by the accumulation of Joule heat under high electric field. Despite of the enhanced electric displacement, BTO/PI nanocomposites exhibit low discharge energy density due to the substantially compromised breakdown strength induced by the BTO nanoparticles. [ABSTRACT FROM AUTHOR]

Presents evidence for rhenium enrichment in the mantle wedge from submarine arc-like volcanic glasses in Papua New Guinea. Concentrations of rhenium in subaerial arc-type volcanic rocks; Loss of rhenium during magma degassing.

Presents a study which observed the neodymium and strontium isotopic disequilibriums between garnet and retrograded omphacite as well as secondary phengite in eclogite from the Yangkou area, near Qingdao, eastern China. Geological setting and samples; Analytical procedures; Results and discussion.

Presents a study which determined the rhenium-osmium concentrations and the osmium isotopic compositions of the Dongling iron meteorite using the negative thermal ionization mass-spectrometry technique. Analytical methods and results; Discussion; Conclusion.

• Upper and lower limits on the accuracy of soil moisture estimation are evaluated using advanced regression models with multi-source data. • The three proposed strategies can improve the temporal transfer performance of soil moisture. • Soil parameters are crucial for the temporal robustness and transferability of soil moisture estimation. • Factors affecting the accuracy of soil moisture in heterogeneous regions are analyzed. The accurate monitoring of the spatio-temporal distribution of surface soil moisture (SSM) is crucial to understanding Earth's water cycle. The machine learning regression (MLR) algorithm has brought a new breakthrough to SSM remote sensing estimation due to its powerful nonlinear fitting ability. However, the high-precision estimation of temporal SSM still faces challenges. In this study, we evaluated the temporal robustness and transfer performance of six MLR algorithms for SSM estimation and conducted a universality experiment in agricultural areas with abundant land cover types. First, the factors affecting the estimation accuracy of SSM were analyzed from the perspectives of dynamic variables (backscattering, multi-spectrum, and brightness temperature [TB]) and steady variables (soil texture [ST] and soil roughness [SR]). Results showed that radar incidence angle (RIA) is the key factor for estimating SSM accurately from dual polarization backscattering (dual-pol σ) data. The introduction of multi-spectrum data can considerably improve the estimation accuracy of SSM and is better than that of TB data. The physical measures (ST) or geometric measures (SR) can be used as auxiliary features for multi-spectrum or TB data, which improve the accuracy of SSM estimated from dual-pol σ data, with similar improvement effects. Multi-source data can effectively reduce the adverse effects of surface heterogeneity on SSM estimation. Ensemble learning and kernel learning algorithms have similar performance in the case of low-dimensional features and small samples. However, the neural network algorithms can correctly reflect the temporal variation of SSM only in the case of multi-dimensional features and large samples. The optimal accuracy of multi-temporal SSM is estimated by the Gaussian process regression algorithm (RMSE = 0.028 cm3/cm3). Moreover, to address poor transfer performance of temporal SSM in MLR models (RMSE > 0.060 cm3/cm3), this study proposed three strategies including the constraint of target domain samples, scattering model, and clustering model. The optimal error (RMSE) of multi-temporal SSM estimated by the three strategies is 0.032, 0.045, and 0.045 cm3/cm3. Overall, the strategies proposed can mitigate the issue of overestimation or underestimation resulting from the inconsistent distribution of SSM and RIAs at various phases. The soil parameters, acting as the medium across different phases, can notably enhance the temporal transfer performance of SSM regression models. This study introduces a novel framework for achieving high estimation accuracy and transfer performance of temporal SSM at a regional scale. [ABSTRACT FROM AUTHOR]

The article discusses cretaceous gold deposits of North China Craton (NCC), China and Carlin-type gold deposits of Nevada collectively referred to as decratonic gold deposits, describes their formation and exploration opportunities, and presents a geological map of NCC indicating gold deposits.

Background • Chemotherapy-induced peripheral neuropathy (CIPN), one of the most common adverse events associated with chemotherapy, may affect efficacy because of the interruption of chemotherapy or change of regimen in severe cases, and may even increase cancer mortality. Relevant data supports the evidence that acupuncture can treat pain and sensory abnormalities. However, choosing the most effective acupuncture therapy is difficult because of the lack of evidence-based medicine and comparisons between different acupuncture therapies for treating CIPN. The aim of this study was to use a network meta-analysis (NMA) to evaluate the efficacy of different acupuncture therapies for CIPN. Methods • We searched Embase, PubMed, Web of Science, The Cochrane Library, The Chinese Journal Full Text Database, Chinese Biomedical Literature Database, and WanFang Database for randomized controlled trials (RCTs) of acupuncture for CIPN. The search period was from the creation of the relevant library to August 10, 2023. A total of 2 investigators independently performed literature screening, data extraction, and risk for bias evaluation. Stata 14.0 software (StataCorp LLC, College Station, Texas USA), was used for the NMA. Results • A total of 13 eligible RCTs involving 746 patients and 6 acupuncture therapies were included in the study. The NMA results showed that electroacupuncture was superior to moxibustion, manual acupuncture, acupoint injection and Western medicine in improving the total effective rate of treatment of CIPN; electroacupuncture + moxibustion was better than manual acupuncture, acupoint injection, and Western medicine. Manual acupuncture’s total effective rate was better than Western medicine. However, electroacupuncture was the most effective treatment for CIPN according to the surface under the cumulative ranking curve (SUCRA) ranking. Conclusion • After a comprehensive evaluation of 6 acupuncture therapies for treating CIPN based on NMA, electroacupuncture may be the best option for treating CIPN. However, would be more convincing to get evidence from more RCTs. [ABSTRACT FROM AUTHOR]

Porphyry Mo deposits are important suppliers of molybdenum for industrial applications, but the origin and source of metals in these deposits remain debated. Here, we present Mo isotope data for Miocene mineralized porphyritic monzogranites (MPMs) and Paleocene barren biotite monzogranites and tuffs (BMTs) from the Bangpu porphyry Mo (Cu) deposit in the Gangdese metallogenic belt. The results show that the MPMs display radiogenic Sr and Pb isotopes and elevated δ98/95Mo (relative to NIST SRM 3134; +0.07%c-1.2%c) and Mo contents, which exceed the range of the depleted mantle. These characteristics cannot be attributed to surface weathering, hydrothermal alteration, magmatic differentiation, or partial melting but rather reflect the incorporation of Mo from black shales into their magma sources, as evidenced by the significant correlations between δ98/95Mo and εNd(i) and aluminum saturation index (ASI) values. In contrast, the BMTs display lower Mo and δ98/95Mo values than the mineralized samples, and their δ98/95Mo values display no correlations with radiogenic isotopes or ASI values. The contrasting characteristics of mineralized and barren samples provide strong evidence that the addition of black shales played an important role in the formation of the Bangpu porphyry Mo deposit. Our study thus establishes a possible link between porphyry Mo deposits and organic-rich sediments and highlights the great potential of Mo isotopes in studying porphyry Mo deposits. [ABSTRACT FROM AUTHOR]

Whether or not oceanic crust basalts are affected by plate subduction is a hot topic of debate. The South China Sea is one of the largest marginal basins in the western Pacific Ocean and has been surrounded by subduction of the Pacific plate and Indian plate, yet, to date, no study has clearly shown evidence of subduction in the geochemistry of volcanism in the basin due to a lack of sampling of igneous crust basalts on the seafloor. The International Ocean Discovery Program Expedition 349 cored seafloor basalts near the fossil spreading ridges of the eastern (Site U1431) and southwestern (Site U1433 and U1434) subbasins in the South China Sea. The recovered basalt samples indicated a pyroxenite-bearing peridotite mantle source. Here, we report Mg isotopic data from 14 of these oceanic crust basalt samples. The δ26Mg values of most basalts from the three drill holes were higher (up to -0.10‰) than that of the average mantle (-0.25‰). The lack of correlations of δ26Mg with geochemical indices of magmatic processes (e.g., MgO, CaO/Al2O3, La/Sm, Nb/Zr) suggests that crystal fractionation and partial melting had insignificant effects on the Mg isotopic compositions of the South China Sea basalts. Thus, the variations in Mg isotopes were inherited from their mantle sources. Considering the highly varied Ce/Pb ratios and elevated 87Sr/86Sr values but mantle-like 143Nd/144Nd values, we propose that the varied δ26Mg values were likely caused by metasomatism of subduction-released fluids. The coupling of Mg and Sr-Fe isotopes provides robust evidence that the high-δ26Mg values of the South China Sea basalts resulted from mixing among pyroxenite-bearing peridotite mantle, the nearby Hainan plume materials, and subducting serpentinite-released fluids. Therefore, these Mg isotopes suggest that the mantle source of the South China Sea basalts was influenced by subducted materials, providing further evidence of the initial expansion, formation, and evolution of the South China Sea during plate subduction. [ABSTRACT FROM AUTHOR]

Plants using the C4 photosynthetic pathway, commonly tropical and subtropical grasses, increased in abundance in East Asia during the late Cenozoic. Determining the exact timing and likely factors leading to this major vegetation change requires region-specific studies. Here variations in pyrogenic carbon mass accumulation rate (PyC-MAR) and isotope composition (δ13CPyC) from an ~7-m.y.-long depositional sequence from the central Loess Plateau, China, suggest increased biomass burning and an increased contribution to combusted material from C4 taxa from 2.6 Ma. Changes in the composition of PyC after 0.6 Ma likely reflect the effects of lower temperatures, particularly during glacial periods, and changes in seasonality of precipitation. Increased PyC-MAR without concomitant changes in δ13CPyC at ca. 0.15 Ma appears to indicate a decoupling of feedbacks between changes in climate, fire regime, and vegetation, and may mark the onset of anthropogenic burning in the region. These new data suggest that C4 taxa were present on the Loess Plateau from at least the late Miocene, rising to prominence at ca. 2.6 Ma following changes in climate and, critically, an increase in biomass fires. [ABSTRACT FROM AUTHOR]

Increasing evidence shows that the mantle contributes (directly or indirectly) to Sn-bearing granites worldwide. However, the specific role of mantle in the formation of tin granites and related mineralization remains poorly understood. In the worldclass Dachang district, South China, tin mineralization is related to the Longxianggai equigranular/porphyritic biotite granites and tin orebodies are cut by granite porphyry dykes hosting mafic microgranular enclaves (MMEs). A combination of zircon U-Pb dating and Hf-O isotopes, mineral chemistry, and whole-rock elemental and Sr-Nd isotopic compositions--for granitic rocks and MMEs, is employed to constrain the petrogenesis and to unravel the link between tin fertility and mantle upwelling. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U-Pb dating indicates that the biotite granites were emplaced at ca. 93 Ma, and the granite porphyry dykes and MMEs were formed at ca. 86 Ma. The biotite granites are silica- and alkali-enriched with A/CNK ratios of 1.04-1.36, and exhibit elevated concentrations of Li, F, P, Rb, Cs, Ta, Sn, W, and U, showing affinities with highly fractionated S-type granites. Whole-rock geochemical and Nd isotopic (eNd(t) = -10.0 to -7.8) data, and in situ zircon Hf-O (eHf(t) = -9.9 to -3.9, d18O = 6.2-8.9?) isotopes indicate that the biotite granites were formed by partial melting of metasedimentary rocks at relatively high temperatures (=782 °C), possibly with minor input of mantle material. Likewise, the post-ore granite porphyry dykes have similar chemical and mineralogical characteristics as fractionated S-type granites. Zircon Hf-O isotopes (eHf(t) = -9.0 to -4.9, d18O = 6.5-8.2?) and whole-rock geochemical data suggest they were derived from a similar source as the biotite granites, whereas elevated eNd(t) values of -5.0 to -3.3 for granite porphyry dykes relative to biotite granites reveal an increasing mantle input. Distinct eNd(t) (-0.4 and -0.3) and zircon Hf-O (eHf(t) = 1.5-5.0, d18O = 6.5-7.2?) isotopes of the MMEs, suggest that the mafic melt could be sourced from the asthenospheric mantle, contaminated by subcontinental lithospheric mantle/continental crust during magma ascent, and hybridized by felsic melt at emplacement-level. The magmatic sequence in the Dachang district is indicative of an extensional tectonic setting where mantle-derived magmas are predicted to migrate to shallower crustal levels as the crust progressively becomes thinner and hotter. High-temperature partial melting of mature metasedimentary crust triggered by heat input from the upwelled mantle, may contribute to biotite breakdown, which is important for concentrating tin in melts. Fractional crystallization of initially Sn-rich felsic melts under reduced conditions makes further tin enrichment and produces Sn-bearing granites (the Longxianggai pluton). Prolonged mantle upwelling results in distinct magma mixing and the formation of granite porphyry dykes and MMEs. These dykes are highly fractionated with elevated Sn and W contents, which show great potential to form hydrothermal Sn-W mineralization. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is an important component in nitrogen biogeochemical cycling produced through biological processes of nitrification and denitrification in soils, but the production and the consumption processes of NO in temperate mountain soil are less understood. Through laboratory experiments focusing on NO biogenic emissions from six kinds of mountain soils sampled from different vertical landscape zones, that is, coniferous and broadleaf mixed forest (CBF), fir forest (FF), spruce forest (SF), Erman's birch forest (EBF), alpine tundra (AT), and volcanic ash (VA), in the Changbai Mountains, northeastern China, we found that the optimum water-filled pore space (WFPS) for NO production varies between 22.5% and 35% for a range of mountain soils. The optimum soil moisture for the maximum NO emission for a certain soil type, however, was constant and independent of soil temperature. The NO emission potential for forest soils was about 7-50-fold higher than tundra soil and volcanic ash, indicating that it is strongly influenced by nutrient contents in soils. On the basis of laboratory results and field monitoring data, the average NO fluxes from these mountain soils were estimated to be 0.14-29.56 ng N m-2 s-1 for an entire plant growth period. NO emissions mainly occur in wet season for CBF and FF, but in dry season for other soil types. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of miR-486 on rats with acute myocardial infarction (AMI), and its mechanism of action. Methods: A rat model of AMI was established. They were randomly divided into 4 groups, namely, sham, model, agomiR-486 and antagomiR-486 groups, respectively. Rats in these different groups were treated with agomiR-21 (5 μL, 40 nmol/mL), antagomiR-21 (5 μL, 40 nmol/mL) or agomiR-NC (5 μL, 40 nmol/mL), respectively. Then, key miRNAs were sorted out using gene-chip assay and verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. Luciferase reporter gene assay was conducted to determine the interaction between miR-486 and gene of PTEN. After intraperitoneal injection of agomiR-486 and antagomiR-486, hemodynamics was measured to determine the effect of miR-486 on myocardial function of the rats. The effect of miR-486 expression level on the expression of myocardial enzymes in serum, the morphology of myocardial tissues, and the apoptosis of myocardial tissues in rats, were investigated. Additionally, the effect of miR-486 expression level on PTEN/AKT signaling pathway in the rats was determined by Western blotting. Results: The results of gene-chip and qRT-PCR assays revealed that there were 8 differentially expressed genes in rat myocardial tissues in the model group when compared with the sham group. MiR-486 improved the cardiac function of rats and the morphology of myocardial tissues, but reduced AMI-induced apoptosis of myocardial cells and the expression of myocardial enzymes (markers of myocardial injury) in a dose-dependent manner (p < 0.05). The results of luciferase reporter gene assay showed that PTEN was a direct target of miR-486. In rat models of AMI, a raised expression of miR-486 remarkably suppressed the protein expression level of PTEN and up-regulated that of p-AKT/AKT (p < 0.05). Conclusion: MiR-486 protects against AMI in rats probably by targeting PTEN and activating the AKT signaling pathway. The results of the current study may provide new insights for the treatment of AMI. [ABSTRACT FROM AUTHOR]

Objective: This study aims to analyze the effect of lyophilized recombinant human brain natriuretic peptide on the endothelial function of patients with acute myocardial infarction. Methods: One hundred and thirty-six patients with acute myocardial infarction in our hospital were randomly divided into a control group and an experimental group (68 cases each). The patients in the control group were treated by conventional treatment. The patients in the experimental group were treated with lyophilized recombinant human brain natriuretic peptide besides the conventional treatment. The levels of flow-mediated dilatation (FMD), serum nitric oxide (NO), and endothelin-1 were compared between the two groups before and after treatment. Results: Before treatment, there was no significant difference between the two groups in the level of FMD (P>0.05); after treatment, the level of FMD in the experimental group was higher than that in the control group, and the difference was statistically significant (P<0.05); before treatment, there was no significant difference between the two groups in the levels of serum NO and endothelin-1 (P>0.05); after treatment, the levels of serum NO and endothelin-1 in the experimental group significantly improved, which were better than those in the control group (P<0.05). Conclusion: Lyophilized recombinant human brain natriuretic peptide can improve the FMD, increase the content of NO in the blood, and effectively reduce the level of endothelin-1, which is of great significance to improve the endothelial function of patients with acute myocardial infarction and is worth clinical application. [ABSTRACT FROM AUTHOR]

Laser ablation-inductively coupled plasma-quadrupole mass spectrometry analysis on hydrothermal cassiterite was applied to solve the long-standing debate on the age of the central European Erzgebirge-Krušné hory tin province of eastern Germany and the western Czech Republic. Cassiterite samples from the Sadisdorf, Ehrenfriedersdorf, Altenberg, Cinovec-Zinnwald, and Krupka tin deposits have U-Pb ages that overlap within the 2σ uncertainty range, and define a relatively narrow time window of 326 ± 3 to 320 ± 3 Ma. These dates also define the minimum age of the associated highly evolved alkali feldspar granite intrusions, which so far could not be reliably dated by conventional U-Pb, Sm-Nd, Rb-Sr, or 40Ar-39Ar techniques due to high-U metamict zircons and resetting by later thermal events. The time span of ca. 326-320 Ma characterizes the age range of regional rare-metal granite magmatism and associated hydrothermal tin mineralization in the Erzgebirge as a result of exten-sional collapse of the Variscan orogen. [ABSTRACT FROM AUTHOR]

The Late Jurassic-Cretaceous Yanshanian Orogeny (or “Yenshan Movement”), one of the most important tectonothermal events, is first recognized in China, especially eastern China. This Late Mesozoic orogeny, which was initiated most likely by a Mesozoic tectonic switch, strongly reworked or destructed the older continental lithospheres or cratonic keels that are manifested by alternating compressive and extensional deformation, voluminous igneous rocks, and a variety of characteristic magmatic-hydrothermal mineral systems. Despite its first discovery and definition in Yenshan-Yinshan area of North China craton, the Yanshanian Orogeny probably is of global tectonic, magmatic and metallogenic significance. However, there have been hot debates on the precise starting time, accurate duration or time-interval, detailed processes and evolution linked to deep lithospheres, tectonic nature, and geodynamic mechanism(s) of the Yanshanian Orogeny, which inevitably have hindered the understanding of the genesis, mineralizing processes and geodynamic mechanism of the Late Mesozoic magmatic-hydrothermal mineral systems. This Special Issue captures some of the latest research results on the Yanshanian ore deposits that are involved into a few main Mesozoic metallogenic belts or provinces, from northeast to southwest China, including: (1) the Jiaodong Peninsula metallogenic province in the North China Craton, (2) the Middle-Lower Yangtze River Valley metallogenic belt in the central eastern China, (3) the Jiangnan and (4) the Nanling metallogenic belts in the South China Block, (5) the southeastern China Coast metallogenic belt, and (6) the Sanjiang metallogenic belt in southwest China. Through a multidisciplinary study, this Special Issue re-investigated and re-evaluated the relationship between the Late Mesozoic magmatic-hydrothermal mineral systems and the Yanshanian tectonothermal events in the studied metallogenic belts or provinces. A few important contributions to the topic in this Special Issue (Yanshanian metallogeny) are summarized as followings: (1) A new ore-deposit type, i.e. the “intracontinental reactivation” type, has been suggested to interpret the genesis of those Au-(polymetallic) deposits that are hosted within older metamorphic rocks and related to the Late Mesozoic basin-and-range extensional settings; (2) Late Mesozoic re-activation of the preexisting structures by the Yanshanian tectono-thermal event(s) might be an important mechanism controlling the Yanshanian large-scale mineralization; (3) A-type granites formed by partial melting of the Mesoproterozoic crust, but with inputs from mantle-derived melt are also favorable for Sn mineralization, in addition to S-type and I-type granites as previously recognized; (4) Calculated oxygen fugacities (ƒO 2 ) of granitic magmas based on chemical compositions of primary biotite have been confirmed to be effective proxy for distinguishing Cu-Au-Mo-W-Sn-Pb-Zn mineralized granites from barren granites; (5) A significant epoch of W–Sn magmatic-hydrothermal ore system at ca. 145–135 Ma has been identified in the southeastern China Coast metallogenic belt; and (6) In addition to traditional structural geology, mineralogy, petrology, geochemistry and geochronology, new analytical techniques (e.g. Cu isotopes) and data treatment method (e.g., Bi-dimensional empirical mode decomposition) can be used to provide more constraints for deep exploration. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects and safety of recombinant human brain natriuretic peptide (rhBNP) in the treatment of elderly acute myocardial infarction induced cardiac failure. Methods: One hundred and forty-six patients who were diagnosed as elderly acute myocardial infarction induced cardiac failure in the hospital from July 2014 to July 2015 were selected. They were divided into a test group and a control group, 73 each. Patients in both groups were given conventional treatment such as stabilization of atherosclerotic plaques, anti-platelet and remodeling and reversion of myocardium. The curative effects and the incidence of adverse reactions of the two groups were observed. Results: The overall efficacy of the test group and the control group was 87.7% and 65.8% respectively and the difference had statistical significance (P<0.05). The heart rate, urine volume, n-terminal probrain natriuretic peptide level and left ventricular ejection fraction (LVEF) of both groups significantly improved after treatment, and the improvement of the test group was superior to that of the control group (P<0.05). The serum creatinine of the test group remarkably reduced after treatment (P<0.05). The incidence of hypotension and arrhythmia of the test group was lower than that of the control group during hospitalization period (P<0.05). Conclusion: rhBNP can effectively relieve the clinical symptoms, cardiac function indexes and hemodynamic indexes of patients with elderly acute myocardial infarction induced cardiac failure, with a high safety. It can be extensively applied in the treatment of acute myocardial infarction in combination with cardiac failure. [ABSTRACT FROM AUTHOR]

Although deep carbon recycling plays an important role in the atmospheric CO2 budget and climate changes through geological time, the precise mechanisms remain poorly understood. Since recycled sedimentary carbonate through plate subduction is the main light-δ26Mg reservoir within deep-Earth,Mg isotope variation in mantle-derived melts provides a novel perspective when investigating deep carbon cycling. Here, we show that the Late Cretaceous and Cenozoic continental basalts from 13 regions covering the whole of eastern China have low δ26Mg isotopic compositions, while the Early Cretaceous basalts from the same area and the island arc basalts from circum-Pacific subduction zones have mantle-like or heavy Mg isotopic characteristics. Thus, a large-scalemantle low δ26Mg anomaly in eastern China has been delineated, suggesting the contribution of sedimentary carbonates recycled into the upper mantle, but limited into the lower mantle. This large-scale spatial and temporal variation of Mg isotopes in the mantle places severe constraints on deep carbon recycling via oceanic subduction. [ABSTRACT FROM AUTHOR]

Background: Our previous research showed that icariin (1) and its phosphorylated structural modification (2) improved the survival and attenuated oxidative stress and liver dysfunction induced by duck virus hepatitis. In this paper, we were one step closer to determine the structure of phosphorylation icariin (2) by the FT-IR, HRESIMS and 13C NMR. Anti-DHAV activities of 1 and 2 were compared in duck embryonic hepatocytes (DEHs) cultured in vitro and by artificial infection method in vivo. Additionally, the antiviral mechanisms of replication/release in vitro and the DHAV gene expression in vivo of 1 and 2 were analyzed. Results: Compound 2's molecular formula was C33H42O18P. The results indicated that 1 and 2 effectively resisted DHAV invading DEHs, that they decreased the mortality of ducklings challenged with DHAV, and that 2 performed more effectively. 1 and 2 performed evenly on DHAV release; however, 2 restrained virus replication far more effectively. Since the anti-DHAV mechanisms of 1 and 2 in vitro probably involve suppression of replication and release, 2's better performance in anti-DHAV may result from its far more effectively inhibiting virus replication. Conclusions: The compound 2's chemical structure was defined as 8-prenylkaempferol-4'-methylether-3-rhamnosyl-7-(6"-phosphate)-glycoside. 1 and 2 exhibited anti-virus activity on DHAV. Our results suggest that 1 and 2 might become an anti-virus plant material candidate. [ABSTRACT FROM AUTHOR]

The Huoqiu iron ore field in northwest Anhui Province is located in the North China Craton (NCC). As a large banded iron formation (BIF) iron ore field, ore bodies occur in a middle-high grade of Neoarchean metamorphic formation, forming a banded silicon-iron series from north to south. The main ore bodies can be divided into two sub-belts from bottom to upper layers, i.e. the A + B ore belt consisting of leptynite-schist-magnetite-quartz formation, and the D ore belt consisting of schist-marble-hematite-quartz formation. Based on a dataset from geological settings, geophysical and geochemical exploration, ore-forming conditions and structural analysis of the iron deposit, we discuss structural types, sedimentary environments, deep tectonic and ore-controlling factors as well as characteristics and distribution of this colossal BIF ore field in the Huoqiu region. Using LA-ICP-MS techniques, we obtained the oldest U-Pb age of ca. 2.7 Ga for plagioclase amphibolite as its original rock, and 1.8 Ga for magmatic granite in the Huoqiu Group. The Hf isotopes of zircon were also determined, resulting in the oldest Hf model age of 3.5 Ga. Geochemical data indicate that the protolithes of amphibolites belong to a series of subalkaline rocks with enrichments of large ion lithophile elements and depletions of high field strength elements, which are typical volcanic arc rocks. The amphibolites have low K2O concentrations with low ratios of Ti/V (22.7 to 25.9 averaging 24.5), similar to island arc tholeiite. This suggests that the iron deposit and BIF are of the Superior type in the Huoqiu region. [ABSTRACT FROM AUTHOR]

A large and sudden increase in radiocarbon (14C) aroundAD773 are documented in coral skeletons from the South China Sea. The 14C increased by ~15%during winter, and remain elevated for more than 4 months, then increased and dropped down within two months, forming a spike of 45%high in late spring, followed by two smaller spikes. The 14C anomalies coincide with an historic comet collision with the Earth's atmosphere on 17 January AD 773. Comas are known to have percent-levels of nitrogen by weight, and are exposed to cosmic radiation in space. Hence they may be expected to contain highly elevated 14C/12C ratios, as compared to the Earth's atmosphere. The significant input of 14C by comets may have contributed to the fluctuation of 14C in the atmosphere throughout the Earth's history, which should be considered carefully to better constrain the cosmic ray fluctuation. [ABSTRACT FROM AUTHOR]

A method has been developed to determine high-precision Sr/Ca and Mg/Ca ratios in corals by laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES) using aqueous solution standard calibration. Simultaneous determination of the signals of the entire analytical wavelengths by ICP-OES and the high performance of the new type of LA system (Resonetics 193 nm ArF excimer laser-ablation system, RESOlution M-50) improve the precision for elemental ratios. Repeated measurements on a coral base synthesized working standard, BH-7, provide precisions of about 0.4% and 0.8% for the Sr/Ca and Mg/Ca ratios, respectively, which are better than the formerly reported precision by the LA-ICP-MS method, about 1%. Such precision is comparable to those obtained by the solution nebulization-ICP-OES (SN-ICP-OES) method, and is adequate for paleoclimate reconstruction. In addition, the LA-ICP-OES can provide results with much higher spatial/time resolution. Comparisons between the LA and SN methods were handled by measuring along the same track of a coral. The Sr/Ca results by these two methods agree quite well with each other. The LA-ICP-OES method is very promising for the analysis of element/Ca ratios in coral and other carbonates used in paleoclimate studies such as stalagmite. Systematic discrepancy, however, was observed in the Mg/Ca ratios, likely due to the existing state of magnesium in the coral skeleton. [ABSTRACT FROM AUTHOR]

Sensitive high resolution secondary ion mass spectrometry (SHRIMP II), laser ablation inductively coupled plasma mass spectrometry (ICP-MS) and laser Raman spectroscopy have been used to determine the ages in zircons from carbonatite dikes associated with the Bayan Obo giant REE-Nb-Fe deposit, Inner Mongolia, China. Analyses of small amounts of zircon extracted from large samples of three carbonatite dikes yield late Palaeoproterozoic 207Pb/206Pb ages of 1894 ± 27, 1944 ± 20 and 1956 ± 9 Ma. One sample also contained inherited grains with ages up to ~2.55 Ga. Zircon grains, even from a single rock, have a wide range of REE patterns, suggesting that they are probably inherited zircons trapped during magma genesis, not zircons crystallized from a single magma. None of the zircon grains has the extremely high Th/U characteristic of the Bayan Obo ore deposit or of the associated carbonatites. Further, mineral inclusions in the zircon identified by Raman spectroscopy are all silicate minerals (quartz and feldspars), consistent with crystallization of the zircon from silicate, not from carbonate, magmas. The Palaeoproterozoic zircons in the Bayan Obo carbonatite dikes did not crystallize from carbonatite magma at the time of dike emplacement, but were derived from wall rock contamination. The ages obtained from the zircons are consistent with ages measured on basement igneous rocks elsewhere in the Bayan Obo region. [ABSTRACT FROM AUTHOR]

The article discusses trends in HIV prevalence among men who have sex with men (MSM) in Beijing, China. It uses data from three consecutive cross-sectional surveys measuring the prevalence of HIV, syphilis, hepatitis B virus, and hepatitis C virus among MSM from 2004 to 2006. The study showed that there is a possible increase in the incidences of HIV and risky sexual behavior in MSM. It recommends measures to prevent HIV, including MSM-friendly HIV testing and health provider education.

Presents information on a study which established the U-series dating procedure using the isotropic diluting and thermal ionization mass spectrometric (TIMS) technique. Comparison between TIMS and alpha-spectrometry; Results and discussion; Conclusion.