Control of spatially homogeneous distribution of heteroatoms to produce red TiO2 photocatalyst for visible-light photocatalytic water splitting

The authors thank National Natural Science Fundation of China (Nos. 51825204, 51572266, 21633009, 51629201), the Major Basic Research Program, Ministry of Science and Technology of China (2014CB239401), the Key Research Program of Frontier Sciences CAS (QYZDB-SSW-JSC039) for the financial support. G. L. is grateful for the award of the Newton Advanced Fellowship.The strong band-to-band absorption of photocatalysts spanning the whole visible light region (400-700 nm) is critically important for solar-driven photocatalysis. Although it is actively and widely used as photocatalyst for various reactions in the past four decades, TiO2 has a very poor ability to capture the whole-spectrum visible light. Here, by controlling the spatially homogeneous distribution of boron and nitrogen heteroatoms in anatase TiO2 microspheres with a predominance of high-energy {001} facets, a strong visible light absorption spectrum with a sharp edge beyond 680 nm is achieved. The red TiO2 with the homogeneous doping of boron and nitrogen obtained shows no increase in defects like Ti3+ that are commonly observed in doped TiO2. More importantly, it has the ability to induce photocatalytic water oxidation to produce oxygen under the irradiation of visible light beyond 550 nm and also photocatalytic reducing water to produce hydrogen under visible light. These results demonstrate the great promise of using the red TiO2 for visible light photocatalytic water splitting and also provide an attractive strategy for realizing the wide-spectrum visible light absorption of wide-bandgap oxide photocatalysts.PostprintPeer reviewe

Functional Specialization of Cellulose Synthase Isoforms in a Moss Shows Parallels with Seed Plants

The secondary cell walls of tracheary elements and fibers are rich in cellulose microfibrils that are helically oriented and laterally aggregated. Support cells within the leaf midribs of mosses deposit cellulose-rich secondary cell walls, but their biosynthesis and microfibril organization have not been examined. Although the Cellulose Synthase (CESA) gene families of mosses and seed plants diversified independently, CESA knockout analysis in the moss Physcomitrella patens revealed parallels with Arabidopsis (Arabidopsis thaliana) in CESA functional specialization, with roles for both subfunctionalization and neofunctionalization. The similarities include regulatory uncoupling of the CESAs that synthesize primary and secondary cell walls, a requirement for two or more functionally distinct CESA isoforms for secondary cell wall synthesis, interchangeability of some primary and secondary CESAs, and some CESA redundancy. The cellulose-deficient midribs of ppcesa3/8 knockouts provided negative controls for the structural characterization of stereid secondary cell walls in wild type P. patens. Sum frequency generation spectra collected from midribs were consistent with cellulose microfibril aggregation, and polarization microscopy revealed helical microfibril orientation only in wild type leaves. Thus, stereid secondary walls are structurally distinct from primary cell walls, and they share structural characteristics with the secondary walls of tracheary elements and fibers. We propose a mechanism for the convergent evolution of secondary walls in which the deposition of aggregated and helically oriented microfibrils is coupled to rapid and highly localized cellulose synthesis enabled by regulatory uncoupling from primary wall synthesis

The Sihailongwan Maar Lake, northeastern China as a candidate Global Boundary Stratotype Section and Point for the Anthropocene Series

Sihailongwan Maar Lake, located in Northeast China, is a candidate Global boundary Stratotype Section and Point (GSSP) for demarcation of the Anthropocene. The lake’s varved sediments are formed by alternating allogenic atmospheric inputs and authigenic lake processes and store a record of environmental and human impacts at a continental-global scale. Varve counting and radiometric dating provided a precise annual-resolution sediment chronology for the site. Time series records of radioactive (239,240Pu, 129I and soot 14C), chemical (spheroidal carbonaceous particles, polycyclic aromatic hydrocarbons, soot, heavy metals, δ13C, etc), physical (magnetic susceptibility and grayscale) and biological (environmental DNA) indicators all show rapid changes in the mid-20th century, coincident with clear lithological changes of the sediments. Statistical analyses of these proxies show a tipping point in 1954 CE. 239,240Pu activities follow a typical unimodal globally-distributed profile, and are proposed as the primary marker for the Anthropocene. A rapid increase in 239,240Pu activities at 88 mm depth in core SHLW21-Fr-13 (1953 CE) is synchronous with rapid changes of other anthropogenic proxies and the Great Acceleration, marking the onset of the Anthropocene. The results indicate that Sihailongwan Maar Lake is an ideal site for the Anthropocene GSSP

Classification Method of Plug Seedlings Based on Transfer Learning

The classification of plug seedlings is important work in the replanting process. This paper proposed a classification method for plug seedlings based on transfer learning. Firstly, by extracting and graying the interest region of the original image acquired, a regional grayscale cumulative distribution curve is obtained. Calculating the number of peak points of the curve to identify the plug tray specification is then done. Secondly, the transfer learning method based on convolutional neural network is used to construct the classification model of plug seedlings. According to the growth characteristics of the seedlings, 2286 seedlings samples were collected to train the model at the two-leaf and one-heart stages. Finally, the image of the interest region is divided into cell images according to the specification of the plug tray, and the cell images are put into the classification model, thereby classifying the qualified seedling, the unqualified seedling and the lack of seedling. After testing, the identification method of the tray specification has an average accuracy of 100% for the three specifications (50 cells, 72 cells, 105 cells) of the 20-day and 25-day pepper seedlings. Seedling classification models based on the transfer learning method of four different convolutional neural networks (Alexnet, Inception-v3, Resnet-18, VGG16) are constructed and tested. The classification accuracy of the VGG16-based classification model is the best, which is 95.50%, the Alexnet-based classification model has the shortest training time, which is 6 min and 8 s. This research has certain theoretical reference significance for intelligent replanting classification work

Ferromagnetism of concrete

Studying the intrinsic properties of concrete is essential for addressing various aspects of concrete structure design, material selection, and sustainability. In this study, a suspended strong magnetic torsion balance device was designed and constructed to investigate the ferromagnetic properties of concrete specimens and their constituent materials. It was found that sand and cement generally exhibit ferromagnetic properties, while aggregates do not possess ferromagnetic properties. Analysis using powder X-ray diffraction (XRD) and chemical experiments confirmed that the ferromagnetic material in sand and cement is elemental iron. A simplified calculation formula for the magnetic force between concrete specimens and an external magnetic field was derived. Three sets of specimens were designed and fabricated for experimental exploration of ferromagnetic properties and magnetic force measurements. The experimental results demonstrate that plain concrete possesses measurable ferromagnetic properties. The magnetic force of concrete initially experiences a rapid decay followed by a gradual leveling off as the distance (from the magnetic field source to the concrete surface) increases. The decay rate approximately follows a fourth-power relationship with distance. Under a loading condition with an applied magnetic field intensity of 0.2 T, the optimal measurement range for ferromagnetic force in concrete is between 0.02 m and 0.05 m

Experimental Study of Moisture Content Effect on Geotechnical Properties of Solidified Municipal Sludge

Moisture content is an important factor affecting the geotechnical properties of solidified municipal sludge (MMS). Typical municipal sludge in China was chosen to investigate the effects of initial moisture content (defined as w0) on geotechnical properties of MMS solidified by self-developed CERSM solidifying agent. In addition, the microstructure changes of solidified sludge samples in this study were explored with scanning electron microscopy and mercury intrusion porosimetry. Mechanical experiment results showed that the unconfined compressive strength, cohesion, and internal friction angle of the MMS increased with the decrease in initial moisture content, but the permeability coefficient changed oppositely. The permeability coefficient of solidified sludge samples was between 10−8 and 10−10 cm/s. But after the drying-saturated process, the permeability coefficient of MMS can be increased up to 4 times, mainly due to the formation of a considerable number of microconnected pores and microcracks in the process of drying. The research results are of great significance to the safe disposal and utilization of municipal sewage sludge in China

Genistein improves systemic metabolism and enhances cold resistance by promoting adipose tissue beiging

Genistein, a naturally occurring phytoestrogen and a member of the large class of compounds known as isoflavones, exerts protective effects in several diseases. Recent studies indicate that genistein plays a critical role in controlling body weight, obesity-associated insulin resistance, and metabolic disorders, but its target organs in reversing obesity and related pathological conditions remain unclear. In this study, we showed that mice supplemented with 0.2% genistein in a high-fat diet for 12 weeks showed enhanced metabolic homeostasis, including reduced obesity, improved glucose uptake and insulin sensitivity, and alleviated hepatic steatosis. We also observed a beiging phenomenon in the white adipose tissue and reversal of brown adipose tissue whitening in these mice. These changes led to enhanced resistance to cold stress. Altogether, our data suggest that the improved metabolic profile in mice treated with genistein is likely a result of enhanced adipose tissue function. •Genistein supplementation suppresses food intake and reduces body weight, leading to improved systemic metabolism.•Genistein supplementation inhibits adipocyte hypertrophy and promotes WAT beiging in diet-induced obese mice.•A diet supplemented with genistein restores BAT morphology and thermogenic gene expression in diet-induced obese mice.•Genistein supplementation contributes to higher subcutaneous temperature and better adaptation to acute cold challenges

Expression of PHB2 in Rat Brain Cortex Following Traumatic Brain Injury

Prohibitin2 (PHB2) is a ubiquitous, evolutionarily strongly conserved protein. It is one of the components of the prohibitin complex, which comprises two highly homologous subunits, PHB1 and PHB2. PHB2 is present in various cellular compartments including the nucleus and mitochondria. Recent studies have identified PHB2 as a multifunctional protein that controls cell proliferation, apoptosis, cristae morphogenesis and the functional integrity of mitochondria. However its distribution and function in the central nervous system (CNS) are not well understood. In this study, we examined PHB2 expression and cellular localization in rats after acute traumatic brain injury (TBI). Western Blot analysis showed PHB2 level was significantly enhanced at five days after injury compared to control, and then declined during the following days. The protein expression of PHB2 was further analyzed by immunohistochemistry. In comparison to contralateral cerebral cortex, we observed a highly significant accumulation of PHB2 at the ipsilateral brain. Immunofluorescence double-labeling showed that PHB2 was co-expressed with NeuN, GFAP. Besides, PHB2 also colocalized with activated caspase-3 and PCNA. To further investigate the function of PHB2, primary cultured astrocytes and the neuronal cell line PC12 were employed to establish a proliferation model and an apoptosis model, respectively, to simulate the cell activity after TBI to a certain degree. Knocking down PHB2 by siRNA partly increased the apoptosis level of PC12 stimulated by H2O2. While the PHB2 was interrupted by siRNA, the proliferation level of primary cultured astrocytes was inhibited notably than that in the control group. Together with our data, we hypothesized that PHB2 might play an important role in CNS pathophysiology after TBI