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Radiocarbon (14C) has become a unique and powerful tracer in source apportionment of atmospheric carbonaceous particles. In this study, the Asia Pacific Economic Cooperation summit (APEC) held in Beijing in 2014 was used as a demonstration to research the source apportionment of atmosphere PM2.5. We used a 200 kV single stage accelerator mass spectrometer recently completed at China Institute of Atomic Energy (CIAE). The PM2.5 samples related to above case were collected, and the characteristics of radiocarbon in organic carbon (OC) and elemental carbon (EC) in samples were analyzed using the AMS. The results show that the Before-APEC pollution emission mode is different from the During-APEC and After-APEC pollution emission modes. For Before-APEC, During-APEC and After-APEC, the average values of fossil carbon fraction of OC are 0.463, 0.431 and 0.615, respectively, and those of EC are 0.644, 0.561 and 0.687. The fossil source contributions of traffic activities using fossil fuels to OC and EC are 15.8 % and 21.9 %, respectively. The fossil source contributions of industrial activities to OC and EC are 38.0 % and 8.2 %, respectively. It is about 7–10 days that is needed to take to regenerate the PM2.5 pollution caused by human activities.
Echinococcus granulosus sensu stricto (s.s.), Echinococcus multilocularis and Echinococcus canadensis are the common causes of human echinococcosis in China. An accurate species identification tool for human echinococcosis is needed as the treatments and prognosis are different among species. The present work demonstrates a method for the simultaneous detection of these three Echinococcus species based on multiplex polymerase chain reaction (mPCR). Specific primers of this mPCR were designed based on the mitochondrial genes and determined by extensive tests. The method can successfully detect either separated or mixed target species, and generate expected amplicons of distinct size for each species. Sensitivity of the method was tested by serially diluted DNA, showing a detection threshold as less as 0.32 pg for both E. granulosus s.s. and E. canadensis, and 1.6 pg for E. multilocularis. Specificity assessed against 18 other parasites was found to be 100% except weakly cross-react with E. shiquicus. The assay was additionally applied to 69 echinococcosis patients and 38 healthy persons, confirming the high reliability of the method. Thus, the mPCR described here has high application potential for clinical identification purposes, and can further provide a useful tool for evaluation of serology and imaging method.
Compulsive behaviors in obsessive-compulsive disorder (OCD) have been related to impairment within the associative cortical-striatal system connecting the caudate and prefrontal cortex that underlies consciously-controlled goal-directed learning and behavior. However, little is known whether this impairment may serve as a biomarker for vulnerability to OCD.
Using resting-state functional magnetic resonance imaging (fMRI), we employed Granger causality analysis (GCA) to measure effective connectivity (EC) in previously validated striatal sub-regions, including the caudate, putamen, and the nucleus accumbens, in 35 OCD patients, 35 unaffected first-degree relatives and 35 matched healthy controls.
Both OCD patients and their first-degree relatives showed greater EC than controls between the left caudate and the orbital frontal cortex (OFC). Both OCD patients and their first-degree relatives showed lower EC than controls between the left caudate and lateral prefrontal cortex. These results are consistent with findings from task-related fMRI studies which found impairment in the goal-directed system in OCD patients.
The same changes in EC were present in both OCD patients and their unaffected first-degree relatives suggest that impairment in the goal-directed learning system may be a biomarker for OCD.
The East Kunlun Orogen (EKO) is the NW part of the Central China Orogenic Belt, which records the evolutionary history of the Proto- and Palaeo-Tethys Oceans from the Cambrian to the Triassic. An Early Palaeozoic eclogite belt has been recognized in recent years, which extends discontinuously for ∼500 km as three eclogite-bearing terranes. In this study, we report an integrated study of zircon grains from mica-schists accompanying the eclogites, in terms of mineral inclusions, U–Pb age systematics and P–T conditions. The presence of coesite is identified, as inclusions within the metamorphic domain of zircons, which provides unambiguous evidence for subducted terrigenous clastic rocks of the Proto-Tethys Ocean exhumed from coesite-forming depths. U–Pb dating of the metamorphic zircons yields a concordia age of 426.5 ± 0.88 Ma, which is likely to be the time of ultrahigh-pressure metamorphism in the Kehete terrane. P–T calculations suggest that metapelite may have experienced a clockwise P–T path with peak P/T conditions of 685 ± 41 °C and >28 kbar, and equilibrated at 482–566 °C and 5.6–8.9 kbar during subsequent exhumation. The high-pressure – ultrahigh-pressure (HP-UHP) metamorphic belt within the EKO may have formed by collision between the Qaidam Block and the South Kunlun Block, as a consequence of the closure of the Proto-Tethys Ocean.
A compact circularly polarized (CP) rectenna with low profile and high efficiency based on the artificial magnetic conductor (AMC) is proposed in this paper. The receiving CP antenna is a coplanar stripline fed dual rhombic loop with an AMC reflector. The proposed AMC reflector not only improves the antenna gain to 9.8 dBi but also decreases the profile to 0.1 λ0. The AMC reflector also makes the antenna have a harmonic suppression function so the low pass filter between the rectifying circuit and the antenna could be omitted and the rectenna has a compact structure. According to the measured results, the rectenna has the highest conversion efficiency of 76% on the load of 240 Ω with the received power of 117.5 mW. When the linearly polarized transmitting antenna is rotated, the conversion efficiency of the CP rectenna maintains a constant high conversion efficiency of 74%. The compact structure and CP operation of the rectenna made it a good candidate of the wireless battery for some electronic devices and far-distance microwave power transmission.
This paper investigates the global well-posedness of a class of reaction–advection–diffusion models with nonlinear diffusion and Lotka–Volterra dynamics. We prove the existence and uniform boundedness of the global-in-time solutions to the fully parabolic systems under certain growth conditions on the diffusion and sensitivity functions. Global existence and uniform boundedness of the corresponding parabolic–elliptic system are also obtained. Our results suggest that attraction (positive taxis) inhibits blowups in Lotka–Volterra competition systems.
Living Caprini are dominant bovids in the pan-Tibetan area that are strongly adapted to dry steppe and high-mountain meadow habitats. Some taxa with Holarctic distributions, e.g., Ovis Linnaeus, 1758, were thought to originate on the Tibetan Plateau and subsequently dispersed elsewhere, which was depicted as an ‘out of Tibet’ story. However, except for some information on a stem caprine assemblage from the Qaidam Basin, the early evolution of Caprini around the Tibetan Plateau is poorly known. Here, we report new material of Olonbulukia tsaidamensis Bohlin, 1937, which was a member of this stem caprine assemblage, from the Wuzhong region, northern China, confirming the similarity of the Wuzhong Fauna and ‘Qaidam Fauna.’ Based on a biometric study of horncores from the ‘Qaidam’ and Wuzhong faunas, we recognize six taxa from this stem caprine assemblage: O. tsaidamensis, O. sp., Qurliqnoria cheni Bohlin, 1937, Tossunnoria pseudibex Bohlin, 1937, ?Protoryx cf. P. enanus Köhler, 1987, and cf. Pachytragus sp. Among these taxa, Q. cheni and T. pseudibex are probably related to some extant Tibetan endemic species, e.g., the Tibetan antelope, Pantholops hodgsonii (Abel, 1826), and the Himalayan tahr, Hemitragus jemlahicus (Smith, 1826). Others might be ancestral to the Turolian caprine assemblages and even possibly gave rise to the extant Caprina. This work reveals an early radiation of stem caprines along the northern side of the rising Tibetan Plateau and indicates a mixed pattern of pan-Tibetan stem caprine evolution prior to their dispersal out of the Tibetan Plateau.
To assess the effect of famine exposure during early life on dietary patterns, chronic diseases, and the interaction effect between famine exposure and dietary patterns on chronic diseases in adulthood.
Cross-sectional study. Dietary patterns were derived by factor analysis. Multivariate quantile regression and log-binomial regression were used to evaluate the impact of famine exposure on dietary patterns, chronic diseases and the interaction effect between famine exposure and dietary patterns on chronic diseases, respectively.
Adults aged 45–60 years (n 939).
‘Healthy’, ‘high-fat and high-salt’, ‘Western’ and ‘traditional Chinese’ dietary patterns were identified. Early-childhood and mid-childhood famine exposure were remarkably correlated with high intake of the traditional Chinese dietary pattern. Compared with the non-exposed group (prevalence ratio (PR); 95 % CI), early-childhood (3·13; 1·43, 6·84) and mid-childhood (2·37; 1·05, 5·36) exposed groups showed an increased PR for diabetes, and the early-childhood (2·07; 1·01, 4·25) exposed group showed an increased PR for hypercholesterolaemia. Additionally, relative to the combination of non-exposed group and low-dichotomous high-fat and high-salt dietary pattern, the combination of famine exposure in early life and high-dichotomous high-fat and high-salt dietary pattern in adulthood had higher PR for diabetes (4·95; 1·66, 9·05) and hypercholesterolaemia (3·71; 1·73, 7·60), and significant additive interactions were observed.
Having suffered the Chinese famine in childhood might affect an individual’s dietary habits and health status, and the joint effect between famine and harmful dietary pattern could have serious consequences on later-life health outcomes.
In 1885, Fedorov discovered that a convex domain can form a lattice tiling of the Euclidean plane if and only if it is a parallelogram or a centrally symmetric hexagon. This paper proves the following results. Except for parallelograms and centrally symmetric hexagons, there are no other convex domains that can form two-, three- or four-fold lattice tilings in the Euclidean plane. However, there are both octagons and decagons that can form five-fold lattice tilings. Whenever
, there are non-parallelohedral polytopes that can form five-fold lattice tilings in the
-dimensional Euclidean space.
Healthcare-associated infections (HAIs) are a major worldwide public-health problem, but less data are available on the long-term trends of HAIs and antimicrobial use in Eastern China. This study describes the prevalence and long-term trends of HAIs and antimicrobial use in a tertiary care teaching hospital in Hefei, Anhui, China from 2010 to 2017 based on annual point-prevalence surveys. A total of 12 505 inpatients were included; 600 HAIs were recorded in 533 patients, with an overall prevalence of 4.26% and a frequency of 4.80%. No evidence was found for an increasing or decreasing trend in prevalence of HAI over 8 years (trend χ2 = 2.15, P = 0.143). However, significant differences in prevalence of HAI were evident between the surveys (χ2 = 21.14, P < 0.001). The intensive care unit had the highest frequency of HAIs (24.36%) and respiratory tract infections accounted for 62.50% of all cases; Escherichia coli was the most common pathogen (16.67%). A 44.13% prevalence of antimicrobial use with a gradually decreasing trend over time was recorded. More attention should be paid to potential high-risk clinical departments and HAI types with further enhancement of rational antimicrobial use.
We present a recent progress of the SG-II 5PW facility, which designed a multi-petawatt ultrashort pulse laser based on optical parametric chirped-pulse amplification (OPCPA). The prior two optical parametric amplifiers have been accomplished and chirped pulses with an energy of 49.7 J and a full-width-at-half-maximum (FWHM) spectrum bandwidth of 85 nm have been achieved. In the PW-scale optical parametric amplification (OPA), with the pump pulse that has an energy of 118 J from the second harmonic generation of the SG-II 7th beam, the pump-to-signal conversion efficiency is up to 41.9%, which to the best of our knowledge is the highest among all of the reported values for OPCPA systems. The compressed pulse is higher than 37 J in 21 fs (1.76 PW), and the focal spot is
after the closed-loop corrections by the adaptive optics. Limited by the repetition of the pump laser, the SG-II 5PW facility operates one shot per hour. It has successfully been employed for high energy physics experiments.
Previous studies have indicated that some food items and nutrients are associated with uric acid metabolism in humans. However, little is known about the role of dietary patterns in hyperuricaemia. We designed this case–control study to evaluate the associations between dietary patterns and newly diagnosed hyperuricaemia in Chinese adults. A total of 1422 cases and 1422 controls were generated from 14 538 participants using the 1:1 ratio propensity score matching methods. Dietary intake was assessed using a validated self-administered FFQ. Dietary patterns were derived by factor analysis. Hyperuricaemia was defined as concentrations of serum uric acid higher than 7 mg/dl (416·5 μmol/l) for men and 6 mg/dl (357 μmol/l) for women. Three dietary patterns were derived by factor analysis: sweet pattern; vegetable pattern; animal foods pattern. The animal foods pattern characterised by higher intake of an animal organ, seafood and processed meat products was associated with higher prevalence of newly diagnosed hyperuricaemia (Pfor trend<0·01) after adjustment. Compared with the participants in the lowest quartile of the animal foods pattern, the OR of newly diagnosed hyperuricaemia in the highest quartile was 1·50 (95 % CI 1·20, 1·87). The other two dietary patterns were not associated with the prevalence of newly diagnosed hyperuricaemia after adjustment. In conclusion, a diet rich in animal organ, seafood and processed meat products is associated with higher prevalence of newly diagnosed hyperuricaemia in a Chinese population. Further cohort studies and randomised controlled trials are required to clarify these findings.
Because most tested drugs are active against only one of the damaging processes
associated with stroke, other mechanisms may cause cellular death. Thus, a combination of
protective agents targeting different pathophysiological mechanisms may obtain better
effects than a single agent. The major objective of this study was to investigate the
effect of combination therapy with vascular endothelial growth factor (VEGF) and nerve
growth factor (NGF) after controlled ischemic brain injury in rabbits.
Methods: Animals were randomly assigned to one of the
following groups: sham group, saline-treated control group or NGF+VEGF-treated group.
Animals received an intracerebral microinjection of VEGF and NGF or saline at 5 or 8 hours
after ischemia. The two specified time points of administration were greater than or equal
to the existing therapeutic time window for monoterapy with VEGF or NGF alone (3 or 5
hours of ischemia). Infarct volume, water content, neurological deficits, neural cell
apoptosis and the expression of caspase-3 and Bcl-2 were measured.
Results: Compared with saline-treated controls, the
combination therapy of VEGF and NGF significantly reduced infarct volume, water content,
neural cell apoptosis and the expression of caspase-3, up-regulated the expression of
Bcl-2 and improved functional recovery (both p<0.01) when administered
5 or 8 hours after ischemia. The earlier the administration the better the
neuroprotection. Conclusions: These results showed that the
combination therapy with VEGF and NGF provided neuroprotective effects. In addition, the
time window of combination treatment should be at least 8 hours after ischemia, which was
wider than monotherapy. RÉSUMÉ:Les effets d’une polythérapie combinant agents neuro-protecteurs et agents
vasoprotecteurs dans les cas d’ischémie cérébrale.Contexte:Étant donné que la plupart des médicaments préalablement
testés tendent à n’agir contre seulement un des processus de dommage associés aux AVC, il
est possible que d’autres processus entraînent une mort cellulaire. À cet effet, il se
pourrait qu’une combinaison d’agents protecteurs ciblant divers mécanismes
physiopathologiques permette d’obtenir de meilleurs résultats qu’un simple agent. Après
avoir suscité de façon contrôlée des lésions cérébrales ischémiques chez des lapins,
l’objectif principal de la présente étude a donc été de se pencher sur l’impact d’une
polythérapie combinant la protéine dite « facteur de croissance de l’endothélium
vasculaire » (ou « VEGF » en anglais) avec le « facteur de croissance des nerfs » (ou «
NGF » en anglais). Méthodes: Les animaux ont été attribués au hasard à l’un des
groupes suivants : ceux ayant reçu un traitement fictif ; ceux, du groupe témoin, ayant
bénéficié d’un traitement à base de solution saline ; et finalement ceux ayant été traités
au moyen des VEGF et NGF. À noter que les lapins ont reçu une micro-injection
intracérébrale de VEGF et de NGF ou de solution saline 5 heures ou 8 heures à la suite de
leur AVC. Ces deux délais d’administration des VEGF et NGF sont équivalents ou supérieurs
aux délais actuels d’administration des VEGF ou NGF à titre de monothérapie (3 heures ou 5
heures à la suite d’un AVC). Tant le volume des infarctus, le contenu en eau, les déficits
neurologiques ainsi causés, l’apoptose des neurones que l’expression des protéases caspase
3 et des protéines Bcl-2 ont été mesurés. Résultats: Si on la compare au traitement à base de solution saline administré au groupe
témoin, la polythérapie à base de VEGF et de NGF, lorsqu’administrée 5 heures ou 8 heures
à la suite de l’AVC, a su réduire de façon notable le volume des infarctus, le contenu en
eau, l’apoptose des neurones et l’expression des protéases caspase 3. Elle a également
permis de réguler à la hausse l’expression des protéines Bcl-2 en plus d’entraîner une
amélioration de la récupération fonctionnelle (p < 0,01 pour ces deux
aspects). Ainsi donc, plus tôt l’on opte pour cette polythérapie, meilleure sera la
neuroprotection encourue. Conclusions: Ces résultats démontrent que la polythérapie à base de VEGF et de NGF procure
des effets neuroprotecteurs. Quant au délai d’administration de ce traitement
combinatoire, il devrait être d’au moins 8 heures à la suite d’un AVC, ce qui est plus
élevé que la monothérapie.
Two new species of egg parasitoids, Oobius saimaensis Yao and Mottern new species and Oobius fleischeri Yao and Duan new species (Hymenoptera: Encyrtidae), are described from eggs of Agrilus fleischeri Obenberger, 1925 (Coleoptera: Buprestidae). Agrilus fleischeri is a phloem-feeding woodborer of poplar (Populus Linnaeus; Salicaceae) in northeastern China. These two species can be distinguished morphologically as O. fleischeri has five tarsomeres and O. saimaensis has four tarsomeres. Although O. saimaensis is morphologically similar to its sympatric congener O. agrili Zhang and Hang, 2005, an important natural enemy of the invasive emerald ash borer, Agrilus planipennis Fairmaire, 1888, molecular phylogenetics and morphological data indicate that they are distinct species. Phylogenetic relationships among the new species and other closely related species are also inferred by using DNA sequence data from several ribosomal and mitochondrial genes. In addition, we expand the known distribution of Oobius primorskyensis Yao and Duan, 2016 to include South Korea.
Temporal contrast is one of the crucial physical determinants which guarantee the successful performance of laser–matter interaction experiments. We generally reviewed the influences on the temporal contrast in three categories of noises based on the requirement by the physical mechanisms. The spatiotemporal influences on temporal contrast at the focal region of the chromatic aberration and propagation time difference introduced by large-aperture broadband spatial filters, which were spatiotemporally coupled with compression and focusing, were calculated and discussed with a practical case in SG-II 5 PW ultrashort petawatt laser. The system-wide spatiotemporal coupling existing in large-aperture broadband ultrashort petawatt lasers was proved to be one of the possible causes of temporal contrast degradation in the focal region.
Dietary restriction (DR) is widely regarded as a viable intervention to extend lifespan and healthspan in diverse organisms. The precise molecular regulatory mechanisms are largely unknown. Epigenetic modifications are not stable upon DR and also keep changing with age. Here, we employed whole genome bisulfite sequencing to determine the DNA methylation changes upon DR in adult Drosophila. Our results indicate that although a low level of DNA methylation exists in the adult Drosophila genome, there is no significant difference in DNA methylation levels upon DR when compared to unrestricted flies. This suggests that other epigenetic components such as histone modifications might be altered by DR.
Stimulated Brillouin scattering (SBS) effect is currently the major limitation for the power scaling of single-frequency/narrow linewidth fiber laser systems. A single-mode linearly polarized all-fiber amplifier system is set up to investigate SBS effect in triple-frequency high-power amplifiers. With this amplifier, up to 302 W output power with 83% slope efficiency is achieved and the SBS threshold is scaled up to 12 dB. To the best of our knowledge, this is the highest output power of multifrequency laser from a single-mode polarization maintaining fiber. Good spectral properties and high brightness make this laser source available for the application of second harmonic generation, coherent beam combining.
Shot-peened CM400 maraging steel was used to study the mechanism of enhanced notch fatigue properties of ultra-high strength materials. After shot peening, the specimen surface became rougher, but the transversal machining traces were reduced. The yield strength was slightly improved while the ultimate tensile strength and hardness maintained constant; as a result, the fatigue limit was promoted by about 1.5 times. The nucleated sites of the fatigue fracture were partly changed from the surface to subsurface/interior of the specimen. To further analyze the influencing factors of fatigue properties, the fatigue damage process may be resolved to two aspects: (a) fatigue damage rate affected by shear deformation and (b) fatigue damage tolerance controlled by the dilatation fracture process. Considering the stress state near the notch tip, the hydrostatic stress and maximum shear stress are considered for better understanding these two aspects. It is observed that the fatigue damage tolerance increased while the fatigue damage rate decreased after shot peening. Therefore, the notch fatigue properties of CM400 maraging steels can effectively be improved.