Ceramics are strong but brittle. According to the classical theories, ceramics are brittle mainly because dislocations are suppressed by cracks. Here, the authors report the combined elastic and plastic deformation measurements of nanoceramics, in which dislocation-mediated stiff and ductile behaviors were detected at room temperature. In the synchrotron-based deformation experiments, a marked slope change is observed in the stress–strain relationship of MgAl2O4 nanoceramics at high pressures, indicating that a deformation mechanism shift occurs in the compression and that the nanoceramics sample is elastically stiffer than its bulk counterpart. The bulk-sized MgAl2O4 shows no texturing at pressures up to 37 GPa, which is compatible with the brittle behaviors of ceramics. Surprisingly, substantial texturing is seen in nanoceramic MgAl2O4 at pressures above 4 GPa. The observed stiffening and texturing indicate that dislocation-mediated mechanisms, usually suppressed in bulk-sized ceramics at low temperature, become operative in nanoceramics. This makes nanoceramics stiff and ductile.

Sn–Sb alloy is an ideal candidate for lead-free solder; however, its performance has been inferior to that of Sn–Pb alloy. Here, the authors used ab initio molecular dynamics simulation to investigate the interatomic interaction in Sn–Sb-based lead-free solders. By calculating the electron density distribution, bond population, and partial density of states, the authors found that the Sn–Sb bonds are a mixture of nonlocalized metal and localized covalent bonds. The covalent bond between Sn and Sb is easy to break at higher temperatures, so Sn–Sb (6.4 wt%) had better fluidity than other studied Sn–Sb alloys. Furthermore, adding Cu or Ag into Sn–Sb alloys can decrease the strength of covalent bonds and stabilize the metal bonds, which improves the metallicity and wettability of the Sn–Sb–Cu and Sn–Sb–Cu–Ag systems when the temperature increases. These results are all in good agreement with experimental findings and have significant value for the development of new solder alloys.

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.

UUID: http://zoobank.org/44de9472-7e3f-42d1-9554-7b3434df91d9

Chickenpox is a common acute and highly contagious disease in childhood; moreover, there is currently no targeted treatment. Carrying out an early warning on chickenpox plays an important role in taking targeted measures in advance as well as preventing the outbreak of the disease. In recent years, the infectious disease dynamic model has been widely used in the research of various infectious diseases. The logistic differential equation model can well demonstrate the epidemic characteristics of epidemic outbreaks, gives the point at which the early epidemic rate changes from slow to fast. Therefore, our study aims to use the logistic differential equation model to explore the epidemic characteristics and early-warning time of varicella. Meanwhile, the data of varicella cases were collected from first week of 2008 to 52nd week of 2017 in Changsha. Finally, our study found that the logistic model can be well fitted with varicella data, besides the model illustrated that there are two peaks of varicella at each year in Changsha City. One is the peak in summer–autumn corresponding to the 8th–38th week; the other is in winter–spring corresponding to the time from the 38th to the seventh week next year. The ‘epidemic acceleration week’ average value of summer–autumn and winter–spring are about the 16th week (ranging from the 15th to 17th week) and 45th week (ranging from the 44th to 47th week), respectively. What is more, taking warning measures during the acceleration week, the preventive effect will be delayed; thus, we recommend intervene during recommended warning weeks which are the 15th and 44th weeks instead.

The paper presents an experimental investigation on the flow-induced vibrations of two tandem circular cylinders for spacing ratio $L/D=1.2{-}6.0$ and reduced velocity $U_{r}=3.8{-}47.8$ , where $L$ is the cylinder centre-to-centre spacing and $D$ is the cylinder diameter. Both cylinders are allowed to vibrate only laterally. Extensive measurements are conducted to capture the cylinder vibration and frequency responses, surface pressures, shedding frequencies and flow fields using laser vibrometer, hotwire, pressure scanner and PIV techniques. Four vibration regimes are identified based on the characteristics and generation mechanisms of the cylinder galloping vibrations. Several findings are made on the mechanisms of vibration generation and sustainability. First, the initial states (vibrating or fixed) of a cylinder may have a pronounced impact on the vibration of the other. Second, alternating reattachment, detachment, rolling up and shedding of the upper and lower gap shear layers all contribute to the vibrations. Third, the gap vortices around the base surface of the upstream cylinder produce positive work on the cylinder, sustaining the upstream cylinder vibration. Fourth, reattachment, detachment and switching of the gap shear layers result in largely positive work on the downstream cylinder, playing an important role in sustaining its vibration.

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 (P for 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.

We designed a resorcinol-formaldehyde (RF) sol–gel ink for direct ink writing of the microlattices. To improve the formability, the fresh microlattices were strengthened by surface catalysis with HCl atmosphere. After supercritical drying and carbonization, the sample’s specific surface area was 631 m2/g and the average pore size was 3.81 nm. Both RF aerogel and carbonized RF aerogel samples had millimeter-scale pore, micron-scale pore, and nanoscale skeleton. The pore and skeleton could provide high surface area and diffusion channels, which were beneficial to the adsorption performances. The carbonized RF aerogel sample fully adsorbed Dulbecco’s modified eagle medium in 250 min, which exhibited a good capacity of quick adsorption and indicated the potential application for cell supports.

To evaluate whether the photocatalysis efficiency of titanium oxide (TiO2) increases under the shading of carbon aerogel (CA), super black CA/TiO2 composite sheets were directly fabricated by physical mixing of CA, TiO2 powder, and binder. It was found that the photocatalysis efficiency of composite sheets were higher than that of pure TiO2 sheet. We attribute this phenomenon to the hot electrons coupling between CA and TiO2. Besides the direct light absorption of TiO2, the hot electrons generating and indirect energy transfer from CA to TiO2 may enhance the photocatalysis efficiency of TiO2.

Previous studies have demonstrated adverse mental health effects of Pb exposure. The purpose of this study is to investigate the relationship between consumption of preserved egg (PE), a high-Pb-containing food and depressive symptoms among adults in China. A sample of 25 213 adults (mean age 41·4 (sd 11·8) years; males, 53·9 %) in Tianjin, China, was studied in a cross-sectional analysis. Dietary intake including PE was assessed using a valid self-administered FFQ. Depressive symptoms were assessed using the Self-Rating Depression Scale (SDS). The association was estimated by OR using logistic regression models adjusted for multiple confounders. The prevalence of elevated depressive symptoms was 6·6 % (SDS≥50). Compared with the least frequent PE consumption (<once/week), multivariable adjusted OR for elevated depressive symptoms were 1·52 (95 % CI 1·28, 1·81), 2·24 (95 % CI 1·76, 2·81) and 3·31 (95 % CI 2·52, 4·30) for consumption of once, 2–3 times and ≥4 times/week, respectively (P for trend<0·0001), indicating a clear dose–response relationship. The results suggested that higher consumption of PE was strongly associated with depressive symptoms among adults in China. These findings underscore the need to consider dietary Pb exposure as a risk factor for psychological distress.

This paper presents a systematic study of the cross-flow-induced vibration on a spring-supported circular cylinder of diameter $D$ placed in the wake of a fixed cylinder of smaller diameter $d$ . The ratios $d/D$ and $L/d$ are varied from 0.2 to 1.0 and from 1.0 to 5.5, respectively, where $L$ is the distance between the centre of the upstream cylinder to the forward stagnation point of the downstream cylinder. Extensive measurements are conducted to capture the cylinder vibration and frequency responses, surface pressure, shedding frequencies and flow fields using laser vibrometer, hot-wire, pressure scanner and particle image velocimetry techniques. Six distinct flow regimes are identified. It has been found that a violent vibration may erupt for the spring-supported cylinder, and its dependence on $d/D$ and $L/d$ is documented. A careful examination and analysis of the flow structure, along with the simultaneously captured pressure distribution around and vibration of the downstream cylinder, cast light upon the mechanisms behind this vibration and its sustainability. The roles of added mass, flow-induced damping and physical aspects in the process of initiating the vibration are discussed in detail.

A low-cost, compact, short-pulse ice-penetrating radar (IPR) system with a center frequency of 50 MHz for sounding glacier topography is presented. The radar was developed to measure ice thickness and to image internal structures and basal conditions of glaciers and ice sheets with a maximum range of ∼16000 ns and a depth resolution better than 2.5 m. The receiver of the IPR system employs asynchronous operation mode, avoiding the need for a cable between the transmitter and receiver. A new sampling technology using a high-speed field programmable gate array, which implements a 256-trace stacking algorithm to realize the analog-to-digital conversion, both simplifies the structure of the receiver and increases the sampling efficiency. The power consumption of the whole receiver is <1.5 W, which can be supplied by a laptop computer. Test measurements were made during the 5th China Expedition to the Grove Mountains in East Antarctica. Field tests show the capability of this system to measure ice thickness up to 650 m and to define internal layers within the ice body.

Super-black carbon aerogel sleeves (CAS) with different reflectivities and a clear aperture had been made, by the sol–gel polycondensation of resorcinol (R) and formaldehyde (F) under the catalysis of sodium carbonate (C), and was used to eliminate stray light. We explained that the subwavelength structure is the main factor that leads to the low reflectivity of CA and constructed a simple optical system to measure the exit power from CAS in different directions. We proved that different CASs have different matting effects, and all of these CASs have better matting effects than that of monolithic graphite that has higher reflectivity. To show the fine angular resolution ability of CAS, we measured the faculae from the reflected light of a compact disc and found that the CAS with a clear aperture of 1.0 mm is the best. The super-black CAS could be used in precision optical instruments and to eliminate stray light in the optical.

This article outlines the evolution of a rescue team in responding to adenovirus prevention with a deployable field hospital. The local governments mobilized a shelter hospital and a rescue team consisting of 59 members to assist with rescue and response efforts after an epidemic outbreak of adenovirus. We describe and evaluate the challenges of preparing for deployment, field hospital maintenance, treatment mode, and primary treatment methods. The field hospital established at the rescue scene consisted of a medical command vehicle, a computed tomography shelter, an X-ray shelter, a special laboratory shelter, an oxygen and electricity supply vehicle, and epidemic prevention and protection equipment. The rescue team comprised paramedics, physicians, X-ray technicians, respiratory therapists, and logistical personnel. In 22 days, more than 3000 patients with suspected adenovirus infection underwent initial examinations. All patients were properly treated, and no deaths occurred. After emergency measures were implemented, the spread of adenovirus was eventually controlled. An emergency involving infectious diseases in less-developed regions demands the rapid development of a field facility with specialized medical personnel when local hospital facilities are either unavailable or unusable. An appropriate and detailed prearranged action plan is important for infectious diseases prevention. (Disaster Med Public Health Preparedness. 2018;12:109–114)

Formation of a nanometer-scale oxide surface layer is common when a material is exposed to oxygen-containing environment. Employing aberration-corrected analytical transmission electron microscopy and using single crystal SnSe as an example, we show that for an alloy, a second thin amorphous layer can appear underneath the outmost oxide layer. This inner amorphous layer is not oxide based, but instead originates from solid-state amorphization of the base alloy when its free energy rises to above that of the metastable amorphous state; which is a result of the composition shift due to the preferential depletion of the oxidizing species, in our case, the outgoing Sn reacting with the oxygen atmosphere.

In this paper, we present a preconditioned positive-definite and skew-Hermitian splitting (PPSS) iteration method for continuous Sylvester equations AX + XB = C with positive definite/semi-definite matrices. The analysis shows that the PPSS iteration method will converge under certain assumptions. An inexact variant of the PPSS iteration method (IPPSS) has been presented and the analysis of its convergence property in detail has been discussed. Numerical results show that this new method is more efficient and robust than the existing ones.

To study the transition from the Paleolithic to the Neolithic period and its duration, samples of charcoal, bone, flowstone and shells excavated from Bailiandong and Miaoyan caves, Guangxi Zhuang autonomous region, South China were dated using the Peking University AMS facility and liquid scintillation counter. The remains excavated from these sites show typical characteristics of the transition from the Paleolithic to the Neolithic. Radiocarbon dating results show a rapid transition from ca. 20 to 10 ka bp.

SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%. We review the laser system and introduce the SG-III laser performance here.

Ice algae have successfully adapted to the extreme environmental conditions in the Antarctic, however the underlying mechanisms involved in the regulation and response of thylakoid membranes and chloroplast to low-temperature stress are still not well understood. In this study, changes in pigment concentrations, lipids, fatty acids and pigment protein complexes in thylakoid membranes and chloroplast after exposure to low temperature conditions were investigated using the Antarctic ice algae Chlamydomonas sp. ICE-L. Results showed that the chloroplasts of Chlamydomonas sp. ICE-L are distributed throughout the cell except in the nuclear region in the form of thylakoid lamellas which exists in the gap between organelles and the starch granules. Also, the structure of mitochondria has no obvious change after cold stress. Concentrations of Chl a, Chl b, monogalactosyl diacylglycerol, digalactosyl diacylglycerol and fatty acids were also observed to exhibit changes with temperature, suggesting possible adaptations to cold environments. The light harvesting complex, lutein and β-carotene played an important role for adaptation of ICE-L, and increasing of monogalactosyl diacylglycerol and digalactosyl diacylglycerol improved the overall degree of unsaturation of thylakoid membranes, thereby maintaining liquidity of thylakoid membranes. The pigments, lipids, fatty acids and pigment-protein complexes maintained the stability of the thylakoid membranes and the normal physiological function of Chlamydomonas sp. ICE-L.

The present study evaluated the effects of dietary microbial phytase on the growth and gut health of hybrid tilapia (Oreochromis niloticus ♀×Oreochromis aureus ♂), focusing on the effect on intestinal histology, adhesive microbiota and expression of immune-related cytokine genes. Tilapia were fed either control diet or diet supplemented with microbial phytase (1000 U/kg). Each diet was randomly assigned to four groups of fish reared in cages (3×3×2 m). After 12 weeks of feeding, weight gain and feed conversion ratio of tilapia were not significantly improved by dietary microbial phytase supplementation. However, significantly higher level of P content in the scales, tighter and more regular intestinal mucosa folds were observed in the microbial phytase group and the microvilli density was significantly increased. The adhesive gut bacterial communities were strikingly altered by microbial phytase supplementation (0·41<similarity coefficient<0·54). Stimulated intestinal inflammation and stress status were observed in the fish fed diet supplemented with microbial phytase, as indicated by the up-regulated intestinal expressions of the cytokine genes (tnf-α and tgf-β) and hsp70. In addition, the gut microvilli height was significantly decreased in the phytase group. These results indicate that dietary microbial phytase may exert mixed effects on hybrid tilapia, and can guide our future selection of phytases as aquafeed additives – that is, eliminating those that can stimulate intestinal inflammation.

Intra-uterine growth restriction (IUGR) impairs postnatal growth and skeletal muscle development in neonatal infants. This study evaluated whether dietary β-hydroxy-β-methylbutyrate Ca (HMB-Ca) supplementation during the early postnatal period could improve muscle growth in IUGR neonates using piglets as a model. A total of twelve pairs of IUGR and normal-birth-weight (NBW) male piglets with average initial weights (1·85 (sem 0·36) and 2·51 (sem 0·39) kg, respectively) were randomly allotted to groups that received milk-based diets (CON) or milk-based diets supplemented with 800 mg/kg HMB-Ca (HMB) during days 7–28 after birth. Blood and longissimus dorsi (LD) samples were collected and analysed for plasma amino acid content, fibre morphology and the expression of genes related to muscle development. The results indicate that, regardless of diet, IUGR piglets had a significantly decreased average daily weight gain (ADG) compared with that of NBW piglets (P<0·05). However, IUGR piglets fed HMB-Ca had a net weight and ADG similar to that of NBW piglets fed the CON diet. Irrespective of body weight (BW), HMB-Ca supplementation markedly increased the type II fibre cross-sectional area and the mRNA expression of mammalian target of rapamycin (mTOR), insulin-like growth factor-1 and myosin heavy-chain isoform IIb in the LD of piglets (P<0·05). Moreover, there was a significant interaction between the effects of BW and HMB on mTOR expression in the LD (P<0·05). In conclusion, HMB-Ca supplementation during the early postnatal period could improve skeletal muscle growth and maturity by accelerating fast-twitch glycolytic fibre development in piglets.