Search

Pressure-induced sp 2 -to-sp 3 transitions in graphite have been studied for decades by experiments and simulations. In general, pressures of 15-18 GPa are needed to initiate structural transitions in graphite at room temperature, and the high-pressure phases are usually unquenchable, as evidenced by in situ resistivity and optical transmittance measurements, X-ray diffraction (XRD), and inelastic X-ray scattering (IXS). However, our in situ Raman results show that the onset transition pressure can be as low as 9.7 GPa when using the methanol-ethanol-water (MEW) mixture as the pressure-transmitting medium (PTM), indicated by an additional G D Raman peak caused by the sp 3 bonding between adjacent graphite layers. Moreover, using a combination of XRD, Raman, X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), we show that a small amount of sp 3 bonds associated with a unique feature of cross stacking are present in the recovered samples. Our findings will be useful to understand the intricate structural transitions in graphite-like materials under compression.

To lower the risk of disease and improve health, many nutrients benefit from intestinal-targeted delivery. Here, we present a nutrient-delivery system based on a pH-responsive "wood scroll", in which nutrients are stored, protected, and controllably released through the rolled structure and natural microchannels of a flexible wood substrate, thus ensuring higher bioactivity as well as prolonged steady release of the nutrient load to the intestine. We loaded the wood's natural microchannels with probiotics as a proof-of-concept demonstration. The probiotic-loaded wood scrolls can survive the simulated conditions of the stomach with a high survival rate (95.40%) and exhibit prolonged release (8 h) of the probiotic load at a constant release rate (4.17 × 10 8 CFUs/h) in the simulated conditions of the intestine. Moreover, by modifying the macroscopic geometry and microstructures of the wood scrolls, both the nutrient loading and release behaviors can be tuned over a wide range for customized or personalized nutrient management. The wood scrolls can also deliver other types of nutrients, as we demonstrate for tea polyphenols and rapeseed oil. This wood scroll design illustrates a promising structurally controlled strategy for the delivery of enteric nutrients using readily available, low-cost, and biocompatible biomass materials that have a naturally porous structure for nutrient storage, protection, and controlled release.

Osteosarcoma is a malignant tumor abundant in vascular tissue, and its rich blood supply may have a significant impact on its metabolic characteristics. PDGFRβ is a membrane receptor highly expressed in osteosarcoma cells and vascular wall cells, and its effect on osteosarcoma metabolism needs to be further studied. In this study, we discussed the effect and mechanism of action of PDGFRβ on glucose metabolism in human osteosarcoma ( HOS) cells. GSEA, Pearson's correlation test, and PPI correlation analysis indicated positive regulation of PDGFRβ on aerobic glycolysis in osteosarcoma. The results of qPCR and western blot further confirmed the prediction of bioinformatics. Glucose metabolism experiments proved that PDGF/PDGFRβ could effectively promote aerobic glycolysis in osteosarcoma cells. In addition, the mitochondrial membrane potential (ΔΨm) experiment proved that the metabolic change triggered by PDGFRβ was not caused by mitochondrial damage. The PI3K pathway inhibitor LY294002, MEK pathway inhibitor U0126, or Warburg effect inhibitor DCA was used to perform western blot and glucose metabolism experiments, and the results showed that PDGFBB/PDGFRβ mainly activated the PI3K/AKT/mTOR/c-Myc pathway to promote aerobic glycolysis in osteosarcoma HOS cells. The newly elucidated role of PDGFRβ provides a novel metabolic therapeutic target for osteosarcoma.

The 660-kilometre seismic discontinuity is the boundary between the Earth's lower mantle and transition zone and is commonly interpreted as being due to the dissociation of ringwoodite to bridgmanite plus ferropericlase (post-spinel transition) 1-3 . A distinct feature of the 660-kilometre discontinuity is its depression to 750 kilometres beneath subduction zones 4-10 . However, in situ X-ray diffraction studies using multi-anvil techniques have demonstrated negative but gentle Clapeyron slopes (that is,  the ratio between pressure and temperature changes) of the post-spinel transition that do not allow a significant depression 11-13 . On the other hand, conventional high-pressure experiments face difficulties in accurate phase identification due to inevitable pressure changes during heating and the persistent presence of metastable phases 1,3 . Here we determine the post-spinel and akimotoite-bridgmanite transition boundaries by multi-anvil experiments using in situ X-ray diffraction, with the boundaries strictly based on the definition of phase equilibrium. The post-spinel boundary has almost no temperature dependence, whereas the akimotoite-bridgmanite transition has a very steep negative boundary slope at temperatures lower than ambient mantle geotherms. The large depressions of the 660-kilometre discontinuity in cold subduction zones are thus interpreted as the akimotoite-bridgmanite transition. The steep negative boundary of the akimotoite-bridgmanite transition will cause slab stagnation (a stalling of the slab's descent) due to significant upward buoyancy 14,15 ., (© 2022. The Author(s).)

Objective: To investigate the effect of dichloroacetate (DCA) on Wilms' tumor (WT) G401 cells., Methods: CCK-8 assay was used to detect the influence of DCA on G401 cells viability and 10 mmol/L DCA was selected for subsequent experiments. The expression of glycolysis-related enzymes, such as hexokinase 2 (HK2), pyruvate kinase M2 (PKM2), lactic acid dehydrogenase A (LDHA), pyruvate dehydrogenase kinase 1 (PDK1), and pyruvate dehydrogenase (PDH), were detected by qRT-PCR and western blot. The extracellular lactic acid and glucose concentrations were measured by the lactic acid assay kit and glucose oxidase method kit respectively. Flow cytometry was used to detect the effect of DCA on G401 cells apoptosis. The invasion and migration ability of G401 cells were detected by Transwell assay and wound-healing assay., Results: The results showed that DCA reduced glycolysis-related enzymes expression, inhibited lactic acid production, and glucose consumption. DCA also suppressed cells growth, induced cells apoptosis and inhibited cells invasion and migration., Conclusion: Inhibition of aerobic glycolysis by DCA can reduce the viability of G401 cells, promote cells apoptosis and inhibit cells invasion and migration. Therefore, aerobic glycolysis may be a potential therapeutic target for Wilms' tumor., (Copyright © 2022 by the Association of Clinical Scientists, Inc.)

Solids in nature can be generally classified into crystalline and non-crystalline states 1-7 , depending on whether long-range lattice periodicity is present in the material. The differentiation of the two states, however, could face fundamental challenges if the degree of long-range order in crystals is significantly reduced. Here we report a paracrystalline state of diamond that is distinct from either crystalline or amorphous diamond 8-10 . The paracrystalline diamond reported in this work, consisting of sub-nanometre-sized paracrystallites that possess a well-defined crystalline medium-range order up to a few atomic shells 4,5,11-13 , was synthesized in high-pressure high-temperature conditions (for example, 30 GPa and 1,600 K) employing face-centred cubic C 60 as a precursor. The structural characteristics of the paracrystalline diamond were identified through a combination of X-ray diffraction, high-resolution transmission microscopy and advanced molecular dynamics simulation. The formation of paracrystalline diamond is a result of densely distributed nucleation sites developed in compressed C 60 as well as pronounced second-nearest-neighbour short-range order in amorphous diamond due to strong sp 3 bonding. The discovery of paracrystalline diamond adds an unusual diamond form to the enriched carbon family 14-16 , which exhibits distinguishing physical properties and can be furthered exploited to develop new materials. Furthermore, this work reveals the missing link in the length scale between amorphous and crystalline states across the structural landscape, having profound implications for recognizing complex structures arising from amorphous materials., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

We report a new allotrope of carbon predicted from first principles simulations. This allotrope is formed in a simulated conversion of two-dimensional polymeric C 60 precursor subjected to uniaxial compression at high temperature. The structure is made up of 240 carbon atoms in an orthorhombic unit cell (termed as o-C 240 ) having a mixed sp 2 /sp 3 hybridization with the ratio of about 1:5. o-C 240 is stable at ambient condition and exhibits superior mechanical performance including optimum Vickers hardness (45 GPa) and fracture toughness (4.10 MPa m 1/3 ), outperforming most of widely used hard ceramics. The electronic structure reveals semiconducting ground state with an indirect band gap of 1.72 eV. The simple reaction pathway could accelerate discovery of this allotrope in laboratory, and the simultaneous occurrence of high fracture toughness, superhardness and semiconductivity is expected to find applications for this material., (© 2020 IOP Publishing Ltd.)

Background: The specific role of the corticospinal tract with respect to inattention and impulsive symptoms in children with attention-deficit/hyperactivity disorder (ADHD) has been explored in the past. However, to our knowledge, no study has identified the exact regions of the corticospinal tract that are affected in ADHD. We aimed to determine comprehensive alterations in the white matter microstructure of the corticospinal tract and underlying neuropsychological substrates in ADHD., Methods: We recruited 38 drug-naïve children with ADHD and 34 typically developing controls. We employed a tract-based quantitative approach to measure diffusion parameters along the trajectory of the corticospinal tract, and we further correlated alterations with attention and response inhibition measures., Results: Compared with controls, children with ADHD demonstrated significantly lower fractional anisotropy and higher radial diffusivity at the level of cerebral peduncle, and higher fractional anisotropy at the level of the posterior limb of the internal capsule in the right corticospinal tract only. As well, increased fractional anisotropy in the posterior limb of the internal capsule was negatively correlated with continuous performance test attention quotients and positively correlated with reaction time on the Stroop Colour–Word Test; increased radial diffusivity in the right peduncle region was positively correlated with omissions in the Stroop test., Limitations: The sample size was relatively small. Moreover, we did not consider the different subtypes of ADHD and lacked sufficient power to analyze subgroup differences. Higher-order diffusion modelling is needed in future white matter studies., Conclusion: We demonstrated specific changes in the right corticospinal tract in children with ADHD. Correlations with measures of attention and response inhibition underscored the functional importance of corticospinal tract disturbance in ADHD., Competing Interests: None declared., (© 2020 Joule Inc. or its licensors)

Background: Little is known about the knowledge and attitudes towards human papillomavirus (HPV) and its vaccines among adolescents in mainland China. Also, limited information has been available on how to improve their knowledge and willingness towards HPV and its vaccines to ensure a successful vaccination program in the future., Methods: This was a school-based interventional follow-up study. One urban and one rural junior middle school in Chengdu were selected by convenience sampling. At baseline, half of the grade one students were randomly selected as controls and the rest were interventions. A set of self-administered questionnaires on HPV and its vaccines were completed by both groups at baseline. After that, only the intervention group received a PowerPoint-oriented health education and finished the post-education questionnaires. One year later, both groups completed the same questionnaires as the follow-up survey., Results: In total, 1675 students finished the pre-intervention questionnaires; 751 were from the control group and 924 were from the intervention group. Among them, only 34.3% had heard of cervical cancer/genital warts, while only 15.1% of them had ever heard of HPV. However, 55.2% of students showed their willingness to be vaccinated even before any intervention. Seven variables were found to be associated with the willingness to be vaccinated at baseline. Immediately after the intervention, 88.4% of students were willing to vaccinate themselves. After 1 year, the effectiveness of intervention remained but decreased. Compared with the control group, the intervention group was more aware about cervical cancer, HPV and its vaccines with statistical significance. However, the level of HPV knowledge and willingness to be vaccinated among the intervention group had significantly decreased compared with that immediately after the intervention (P < 0.001)., Conclusions: The baseline level of knowledge on HPV, its vaccines, and cervical cancer was very low among junior middle school students in Chengdu, China. However, the willingness to be vaccinated seemed positive. School-based health education is effective and appropriate in increasing the awareness of HPV and willingness towards its vaccines. Regular health education on HPV and cervical cancer prevention at a shorter interval should be guaranteed to ensure continuous effectiveness.

The discovery of electrides, in particular, inorganic electrides where electrons substitute anions, has inspired striking interests in the systems that exhibit unusual electronic and catalytic properties. So far, however, the experimental studies of such systems are largely restricted to ambient conditions, unable to understand their interactions between electron localizations and geometrical modifications under external stimuli, e.g., pressure. Here, pressure-induced structural and electronic evolutions of Ca 2 N by in situ synchrotron X-ray diffraction and electrical resistance measurements, and density functional theory calculations with particle swarm optimization algorithms are reported. Experiments and computation are combined to reveal that under compression, Ca 2 N undergoes structural transforms from R 3 ¯ m symmetry to I 4 ¯ 2 d phase via an intermediate Fd 3 ¯ m phase, and then to Cc phase, accompanied by the reductions of electronic dimensionality from 2D, 1D to 0D. Electrical resistance measurements support a metal-to-semiconductor transition in Ca 2 N because of the reorganizations of confined electrons under pressure, also validated by the calculation. The results demonstrate unexplored experimental evidence for a pressure-induced metal-to-semiconductor switching in Ca 2 N and offer a possible strategy for producing new electrides under moderate pressure.

Cellulose-based composite macrogels made by cellulose fiber/cellulose nanofiber (CCNM) were used as an intestine delivery vehicle for probiotics. Cellulose nanofiber (CNF) was prepared by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation system, and the carboxyl groups in CNF acted as pore size and pH responsibility regulators in CCNMs to regulate the probiotics loading and controlled release property. The macrogel presented a porosity of 92.68% with a CNF content of 90%, and the corresponding released viable Lactobacillus plantarum (L. plantarum) was up to 2.68 × 10 8 cfu/mL. The porous structure and high porosity benefited L. plantarum cells to infiltrate into the core of macrogels. In addition, the macrogels made with high contents of CNF showed sustainable release of L. plantarum cells and delivered enough viable cells to the desired region of intestine tracts. The porous cellulose macrogels prepared by a green and environmental friendly method show potential in the application of fabricating targeted delivery vehicles of bioactive agents.

Developing an acoustic radiation force excitation module including 64 channels based in FPGA for ultrasound elastography. The circuit of the module was derived in bipolar, and the parameters such as excitation frequency, pulse repetition frequency, pulse number, element number and focus depth were adjustable. The acoustic field for special parameter was experimented with OptiSon laser acoustic field system with a result which reflects the width of focal spot is about 3 mm. The acoustic power was experimented with RFB2000 radiation force balance with a result which reflects acoustic power is increasing linearly with the number of pulses and the number of elements, and is increasing squarely with the peak-to-peak value of excitation voltage. The module is promising in factual application which can be triggered externally in synchronously, and can be combined with B-mode ultrasound system for ultrasound elastography.

Objective: To extract and analyze fatty acids in leaves of L. chinense Oliver and L. chinense var. rubrum Yieh., Methods: The fatty acids were extracted with Soxhlet extractor and identified by the GC-MS method., Results: 31, 26 and 30 components were identified from the leaves of L. chinense, the green leaves and red leaves of L. chinense var. rubrum. There were 19, 14 and 16 kinds of fatty acid in the respective leaves, which accounted for 99.09%, 95.31% and 98.83% of the total extraction, respectively. The main components in the extraction were oleic acid (30.77%, 47.01%, 75.28%), linoleic acid (48.49%, 29.26%, 0%), hexadecanoic acid (9.83%, 8.87%, 11.71%), octadecanoic acid (3.86%, 3.18%, 4.88%) and docosanoic acid (2.37%, 2.17%, 2.58%)., Conclusion: Many kinds of unsaturated fatty acids exist in leaves of L. chinense Oliver and L. chinense var. rubrum Yieh. The leaves of these two plants can be used as the traditional Chinese medicine.

Objective: To investigate the effect of total fiavonoids from Chrysanthemun morifolium (TFCM) on learning and memory, and cholinergic system function in aging mice., Methods: The aging mice model was established by subcutaneous injection of D-galactose. ICR mice were divided into five groups (n=10): contrA group, model group, and TFCM groups. Mice in TFCM groups were given TFCM (50,100 or 150 mg/kg) by gastric irrigation once a day. Learning and memory ability were evaluated by Morris water maze test. The MDA content, SOD and Ach E activity were also measured., Results: Compared with control group, learning and memory ability declined in the D-galactose-induced aging mice; meanwhile MDA content and AchE activity increased, SOD activity decreased. Treatment with TFCM (100, 150 mg/kg) ameliorated the decrease in learning and memory ability of aging mice. Compared with model group, TFCM (100, 150 mg/kg) could also decrease MDA content and Ach E activity, and increase SOD activity in aging mice., Conclusion: TFCM may improve the learning and memory ability of aging mice. The mechanism is involved in its antioxidative characteristic and improvement of central cholinergic system function.