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We recently reported Cambrowania ovata Tang and Xiao in Tang et al., 2019, from the early Cambrian Hetang Formation in South China and interpreted it as a problematic animal fossil, possibly related to either sponges or bivalved arthropods (Tang et al., 2019). Slater and Budd (2019) contested our taxonomic identification and phylogenetic interpretation; instead, they claimed that Cambrowania ovata is a large acritarch referable to morphotaxon Leiosphaeridia Eisenack, 1958, and thus is not an animal. Here we refute their criticisms, clarify the differences between Cambrowania and Leiosphaeridia and other acritarchs, and reiterate why an animal affinity for Cambrowania cannot be ruled out.
The lower-middle Hetang Formation (Cambrian Stage 2–3) deposited in slope-basinal facies in South China is well known for its preservation of the earliest articulated sponge fossils, providing an important taphonomic window into the Cambrian Explosion. However, the Hetang Formation also hosts a number of problematic animal fossils that have not been systematically described. This omission results in an incomplete picture of the Hetang biota and limits its contribution to the understanding of the early evolution of animals. Here we describe a new animal taxon, Cambrowania ovata Tang and Xiao, new genus new species, from the middle Hetang Formation in the Lantian area of southern Anhui Province, South China. Specimens are preserved as carbonaceous compressions, although some are secondarily mineralized. A comprehensive analysis using reflected light microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and micro-CT reveals that the new species is characterized by a spheroidal to fusoidal truss-like structure consisting of rafter-like crossbars, some of which are secondarily baritized and may have been internally hollow. Some specimens have aperture-like structures that are broadly similar to oscula of sponges, whereas others show evidence of a medial split reminiscent of gaping carapaces. While the phylogenetic affinity of Cambrowania ovata Tang and Xiao, n. gen. n. sp. remains problematic, we propose that it may represent carapaces of bivalved arthropods or more likely sponges in early life stages. Along with other problematic metazoan fossils such as hyolithids and sphenothallids, Cambrowania ovata Tang and Xiao, n. gen. n. sp. adds to the diversity of the sponge-dominated Hetang biota in an early Cambrian deepwater slope-basinal environment.
The accelerated retreat of glaciers and the reduction of glacier ice reserves caused by climate change can significantly affect regional water resources and hydrological cycles. Changes in glacier thickness are among the key indicators that reflect this process. We analyzed changes observed in the elevation of glacier surfaces in the Gongga Mountains (GGM) using multi-temporal Digital Elevation Models (DEMs) derived from topographic maps, SRTM, ICESat and ZY-3 data. The results showed that the mean rate of change in glacier surface altitude in the GGM was ~−26.7 ± 2.03 m (0.54 ± 0.04 m a−1) between 1966 and 2015. The mean melt rates differed over different time periods, latterly showing an accelerating trend. As a general rule, glaciers appear to be losing more volume at lower than at higher elevations. Further analysis of these results suggests that supraglacial debris coverage in the GGM promotes higher rates of mass loss.
The magnetism and microstructure of Cr25Ni35Nb and Cr35Ni45Nb alloy tubes after 5 years of service were investigated in this paper. The saturation magnetization of the Cr25Ni35Nb alloy tube in the thickness direction is more than 20 emu/g, and the tube becomes ferromagnetic. The inner and outer walls of Cr35Ni45Nb alloy tubes also become ferromagnetic. But the saturation magnetization of the Cr35Ni45Nb alloy tubes approaches to zero in the center zone. The primary carbides M7C3 and NbC are changed into M23C6 and G phase at the outer region of the furnace tube. However, the M23C6-type carbides were replaced by carbon-rich carbides M7C3 at the carburization zone. Cr-depleted zones are formed at the inner and outer walls of the furnace tubes owing to oxidation. Carburization and oxidation reduce the Cr content of the matrix. Accordingly, the saturation magnetization is very high at the carburization zone and Cr-depleted zone. The magnetism of Cr25Ni35Nb and Cr35Ni45Nb alloy tubes has a high correlation with the Cr content of the matrix. Carburization and oxidation are the main reasons that make the paramagnetic ethylene pyrolysis furnace tube change to ferromagnetic.
Global climate change is causing widespread glacier retreat, with many small glaciers disappearing from the world's mountain ranges. We obtained the annual mass balance of a small glacier (the Ningchan No.1 Glacier) located on the northeastern Tibetan Plateau, from the years 2010 to 2015 using glaciological and geodetic methods. We also measured the glacier's thickness in 2014 using ground-penetrating radar. Employing topographical maps and ZY-3 images, we obtained Digital Elevation Models for 1972 and 2014. Our results showed that the mean annual mass balance from 2010 to 2015 was ~−0.9 ± 0.5 m w.e. The mean equilibrium line altitude was ~4680 m in the period 2010–15, which exceeds the maximum elevation of the glacier. The glacier has lost area and mass across its elevation range. The mean ice thickness was 24.0 ± 2.5 m in 2014. From 1972 to 2014, the glacier's area shrank from 0.77 ± 0.05 to 0.39 ± 0.04 km2, and the ice volume decreased by (14.96 ± 0.97) × 106 m3, equivalent to (12.72 ± 0.82) × 106 t w.e. over the same period.
Global warming is causing widespread glacier retreat, with small glaciers disappearing. We investigate changes in glaciers over the western Lenglongling mountains, located in the northeastern margin of the Tibetan Plateau. Glacier extent over the western Lenglongling mountains is estimated by comparing digitized glacier outlines obtained from aerial photographs and satellite imagery. These results suggest that all 179 glaciers in the western Lenglongling mountains shrunk between 1972 and 2007. The total area loss was ~24.4 km2, accounting for ~28.3% (0.81% a-1) of the glacierized area in 1972. The average area retreat rates differ over different time intervals: they are approximately 0.68, 0.90, 0.77 and 0.56 km2 a-1 over the periods 1972-95,1995-99,1999-2002 and 2002-07, respectively. Based on analysis of meteorological data, glacier shrinkage in the study area can probably be attributed to the increase in air temperature. Furthermore, the smaller glaciers display a higher shrinkage rate than larger glaciers, and glaciers on southwest-facing slopes appear to retreat faster than those on northeast- facing slopes.
We test the hypothesis that investment constraints in delegated portfolio management may distort demand for stocks, leading to price underreaction to news and stock return predictability. We find that institutions tend not to buy more of a stock with good news that they already overweight; they are reluctant to sell a stock with bad news that they already underweight. Stocks with good news overweighted by institutions subsequently significantly outperform stocks with bad news underweighted by institutions. The impact of institutional investment constraints sheds new light on asset pricing anomalies such as stock price momentum and post–earnings announcement drift.
Building on the growing literature on interfirm links and limited attention, we find evidence of return predictability across alliance partners. A long–short portfolio sorted on lagged returns of strategic alliance partners provides a return of 89 basis points per month that is robust to a number of specifications. Investor inattention and limits to arbitrage may be the source of the underreaction of a firm’s returns to that of its partners.
Hydroxytyrosol (HT) is a major polyphenolic compound found in olive oil with reported anti-cancer and anti-inflammatory activities. However, the neuroprotective effect of HT on type 2 diabetes remains unknown. In the present study, db/db mice and SH-SY-5Y neuroblastoma cells were used to evaluate the neuroprotective effects of HT. After 8 weeks of HT administration at doses of 10 and 50 mg/kg, expression levels of the mitochondrial respiratory chain complexes I/II/IV and the activity of complex I were significantly elevated in the brain of db/db mice. Likewise, targets of the antioxidative transcription factor nuclear factor erythroid 2 related factor 2 including p62 (sequestosome-1), haeme oxygenase 1 (HO-1), and superoxide dismutases 1 and 2 increased, and protein oxidation significantly decreased. HT treatment was also found to activate AMP-activated protein kinase (AMPK), sirtuin 1 and PPARγ coactivator-1α, which constitute an energy-sensing protein network known to regulate mitochondrial function and oxidative stress responses. Meanwhile, neuronal survival indicated by neuron marker expression levels including activity-regulated cytoskeleton-associated protein, N-methyl-d-aspartate receptor and nerve growth factor was significantly improved by HT administration. Additionally, in a high glucose-induced neuronal cell damage model, HT effectively increased mitochondrial complex IV and HO-1 expression through activating AMPK pathway, followed by the prevention of high glucose-induced production of reactive oxygen species and declines of cell viability and VO2 capacity. Our observations suggest that HT improves mitochondrial function and reduces oxidative stress potentially through activation of the AMPK pathway in the brain of db/db mice.
We investigate the changes at nine glaciers in the Ningchan and Shuiguan river source, eastern Qilian Mountains, between 1972 and 2010. According to analysis of topographic maps and multispectral satellite data, all nine glaciers in the study area have retreated, by a maximum of 250 ± 57.4 m and a minimum of 91 ± 57.4 m. The total glacier area decreased by 1.20 km2, corresponding to 9.9% of the glacierized area in 1972. Comparing the two DEMs generated from the topographic maps and Real-Time Kinematic GPS data, the mean glacier thinning rate was 0.64 m yr− 1 between 1972 and 2010. The most significant thinning generally occurred on the termini. The ice-volume loss was about 106.8 ± 46.7 × 10− 3 km3 (equal to 90.8 ± 39.7 × 10− 3 km3 w.e.), which suggested a mean water discharge of 0.1 ± 0.05 m3/s during 1972–2010. Based on analysis of meteorological data, the summer temperature (June–August) tends to increase over a similar time period. The consistency of temperature increase and glacier shrinkage allows us to suggest that air temperature plays an important role in glacier changes in this region.
Circulating microRNAs (miRNAs) have received considerable attention as a novel class of biomarkers for the diagnosis of cancer and as signalling molecules in mediating intercellular communication. Schistosomes, the causative agents of schistosomiasis, live in the blood vessels of a mammalian host in the adult stage. In the present study, we characterized schistosome-specific small RNA populations in the plasma of rabbits infected with Schistosoma japonicum (S. japonicum) using a deep sequencing method and then identified five schistosome-specific miRNAs, including four known miRNAs (Bantam, miR-3479, miR-10 and miR-3096), and one novel miRNA (miR-0001, miRBase ID: sja-miR-8185). Four of the five schistosome-specific miRNAs were also detected by real-time RT–PCR in the plasma of S. japonicum-infected mice. In addition, our study indicated that schistosome Argonaute 2/3 may be an excretory-secretory (ES) protein. In summary, our findings are expected to provide useful information for further development of novel biomarkers for the diagnosis of schistosomiasis and also for deeper understanding of the mechanism of host–parasite interaction.
Ecological evidence suggests that niacin (nicotinamide and nicotinic acid) fortification may be involved in the increased prevalence of obesity and type 2 diabetes, both of which are associated with insulin resistance and epigenetic changes. The purpose of the present study was to investigate nicotinamide-induced metabolic changes and their relationship with possible epigenetic changes. Male rats (5 weeks old) were fed with a basal diet (control group) or diets supplemented with 1 or 4 g/kg of nicotinamide for 8 weeks. Low-dose nicotinamide exposure increased weight gain, but high-dose one did not. The nicotinamide-treated rats had higher hepatic and renal levels of 8-hydroxy-2′-deoxyguanosine, a marker of DNA damage, and impaired glucose tolerance and insulin sensitivity when compared with the control rats. Nicotinamide supplementation increased the plasma levels of nicotinamide, N1-methylnicotinamide and choline and decreased the levels of betaine, which is associated with a decrease in global hepatic DNA methylation and uracil content in DNA. Nicotinamide had gene-specific effects on the methylation of CpG sites within the promoters and the expression of hepatic genes tested that are responsible for methyl transfer reactions (nicotinamide N-methyltransferase and DNA methyltransferase 1), for homocysteine metabolism (betaine–homocysteine S-methyltransferase, methionine synthase and cystathionine β-synthase) and for oxidative defence (catalase and tumour protein p53). It is concluded that nicotinamide-induced oxidative tissue injury, insulin resistance and disturbed methyl metabolism can lead to epigenetic changes. The present study suggests that long-term high nicotinamide intake (e.g. induced by niacin fortification) may be a risk factor for methylation- and insulin resistance-related metabolic abnormalities.
FOXJ1 is a member of the Forkhead/winged-helix (Fox) family of transcription factors, which is required for the differentiation of the cells acting as adult neural stem cells which participate in neurogenesis and give rise to neurons, astrocytes, oligodendrocytes. The expression pattern of FOXJ1 in the brain after cerebral ischemia has so far not been described. In the current study, we investigated the expression pattern of FOXJ1 in the rat brain after cerebral ischemia by animal model.
We performed a middle cerebral artery occlusion (MCAO) model in adult rats and investigated the expression of FOXJ1 in the brain by Western blotting and immunochemistry; double immunofluorescence staining was used to analyze FOXJ1's co-expression with Ki67.
Western blot analysis showed that the expression of FOXJ1 was lower than normal and sham-operated brain after cerebral ischemia, but the level of FOXJ1 gradually increased from Day 1 to Day 14. Immuohistochemical staining suggested that the immunostaining of FOXJ1 deposited strongly in the ipsilateral and contralateral hemisphere in the cortical penumbra (CP). There was no FOXJ1 expression in the ischemic core (IC). The positive cells in the cortical penumbra might migrat to the ischemic core. In addition, double immunofluorescence staining revealed that FOXJ1 was co-expressed with mAP-2 and gFAP, and Ki67 had the colocalization with NeuN, GFAP, and FOXJ1.
All our findings suggest that FOXJ1 plays an important role on neuronal production and neurogenesis in the adult brain after cerebral ischemia.
Cu–In–Ga precursor thin films were deposited onto soda lime glass by magnetron cosputtering CuIn and CuGa alloy targets. After that, Cu(In,Ga)Se2(CIGSe) absorbers were formed by selenizing those alloy precursors with Se vapor at 550 °C. The influence of the precursor temperature on the properties of CIGSe thin film was investigated. The results show that a lot of pinholes existed in the CIGSe thin film produced by selenizing the Cu–In–Ga alloy precursor, which was sputtering deposited at ambient temperature. After sputtering substrate temperature of 250 °C was applied, pinholes were avoided. The surface roughness of Cu–In–Ga precursor increased with the increase of sputtering substrate temperature. Due to the volume expansion of selenization process, even the precursor with high surface roughness could be converted to smooth and compact CIGSe thin film.
Processing graphene and graphene polymer nanocomposites in an aqueous medium has always been a big challenge due to the hydrophobic nature of graphene (or reduced graphene oxide) nanosheets. In this work, a waterborne latex of polyurethane has been used both as the matrix material for embedding the graphene nanosheets and as a unique stabilizer to help produce an up to 5 wt% graphene/PU nanocomposites. The graphene oxide/polyurethane latex aqueous suspension is reduced in-situ using hydrazine, without any trace of aggregation/agglomeration upon completion of the reduction process, which would otherwise have occurred severely were PU not present. A highly aligned nanostructure is produced when graphene content is increased beyond 2 wt%, resulting in a remarkable improvement in electrical and mechanical properties of the nanocomposite. The exceptionally low electrical percolation threshold of 0.078%, as well as 21-fold and 14 fold increases in tensile modulus and strength, respectively, have been attained thanks to the alignment of graphene nanosheets in the polymeric matrix.
We made photonic crystals composed of artificial opals infiltrated with ZnS semiconductor nanocrystals by using self-assembly and solvothermal methods. Scanning electron microscopy images show that the silica spheres exhibit a well-ordered arrangement and the ZnS nanocrystals grow homogenously inside the opal matrix and the as-synthesized ZnS nanocrystals reveal a cubic phase from X-ray diffraction pattern. Furthermore, the optical properties of the infiltrated opals with different ZnS filling ratio are also studied by transmission spectroscopy respectively. It is proposed that the position of the stop band can be easily designed by controlling the infiltration ratio of ZnS. These results demonstrate an effective and practical route to obtain high-performance photonic crystal structures.
We studied the microstructures of hydroxyapatite (HA) ceramics which were sintered under three different conditions. It was found that all the ceramics were of sub-micrometer structure. The synthetic HA ceramics were also compared with human enamel. It is concluded that human enamel has higher strength because of its unique microstructure.
The HA coatings were heated separately in vacuum, air and water vapor. The dissolution of the HA coatings was investigated by immersion in Tris buffer and SBF The dissolubility of HA coatings in the solutions decreased in this order: as-received, heated in vacuum, in air and in water vapor. The nucleation of bone-like apatite on the surfaces of HA coatings after immersing a period of 11 days in SBF was observed by SEM. The microenvironment with a sufficient supersaturation of Ca and P ions was crucial for the nucleation and growth of apatite in SBF. The dissolution of amorphous phase in coatings played an important part in establishing the supersaturation of Ca and P ions.
Bramble-like mesostructured nickel oxide/surfactant fibers were synthesized by using anionic surfactants (sodium dodecylsulfonate or sodium dodecylsulfate: SDS) as templates, and nickel salts as inorganic precursors, via the “S-I+” route in alkaline condition. The as-prepared samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetry-differential thermal analysis (TG/DTA) techniques. Such form of mesostructure nickel oxide is found for the first time and is believed to have potential applications in catalysis, host-guest chemistry, and electrochemical devices.
A useful procedure is described to rapidly obtain Bragg-reflection intensities from the FULLPROF suite, and the Bragg intensities can then be input into the GEST and the PECKCRYST programs for crystal-structure determination of small molecules. An example on using the new procedure for the structure determination from powder diffraction determination of hydrochlorothiazide (C7H8ClN3O4S2) is presented, and the powder-structure results obtained by the PECKCRYST program are in good agreement with previously reported single-crystal results.