Experimental investigation on shock mechanical properties of red sandstone under preloaded 3D static stresses

Triaxial impact mechanical performance experiment was performed to study the mechanical properties of red sandstone subjected to three-dimensional (3D) coupled static and dynamic loads, i.e., three confining pressures (0, 5, and 10 MPa) and three axial pressures (11, 27, and 43 MPa). A modified 3D split Hopkinson pressure bar testing system was used. The change trend in the deformation of red sandstone and the strength and failure modes under axial pressures and confining pressures were analyzed. Results show that, when the confining pressure is constant, the compressive strength, secant modulus, and energy absorbed per unit volume of red sandstone initially increases and subsequently decreases, whereas the average strain rate exhibits an opposite trend. When the axial pressure is constant, both the compressive strength and secant modulus of red sandstone are enhanced, but the average strain rate is decreased with increasing confining pressure. The energy absorbed per unit volume is initially increased and subsequently decreased as the confining pressure increases. Red sandstone exhibits a cone-shaped compression–shear failure mode under the 3D coupled static and dynamic loads. The conclusions serve as theoretical basis on the mechanical properties of deep medium-strength rock under a high ground stress and external load disturbance condition

Mineralogical characterization of manganese oxide minerals of the Devonian Xialei manganese deposit

The Guangxi Zhuang Autonomous Region is an important manganese ore district in Southwest China, with manganese ore resource reserves accounting for 23% of the total manganese ore resource reserves in China. The Xialei manganese deposit (Daxin County, Guangxi) is the first super-large manganese deposit discovered in China. The Mn oxide in the supergene oxidation zone of the Xialei deposit was characterized using scanning electron microscopy (SEM), energy spectrometer (EDS), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction analysis (XRD). The Mn oxides have a gray-black/steel-gray color, a semi-metallic-earthy luster, and appear as oolitic, pisolitic, banded, massive, and cellular textures. Scanning electron microscopy images show that the manganese oxide minerals are present as fine-spherical particles with an earthy surface. TEM and HRTEM indicate the presence of oriented bundled and staggered nanorods, and nanopores between the crystals. The Mn oxide ore can be classified into two textural types: (1) oolitic and pisolitic (often with annuli) Mn oxide, and (2) massive Mn oxide. Pyrolusite, cryptomelane, and hollandite are the main Mn oxide minerals. The potassium contents of cryptomelane and pyrolusite are discussed. The unit cell parameters of pyrolusite are refined

Morphology and elemental behavior of borosilicate glass after γ-irradiation and corrosion

Borosilicate glass is currently the best comprehensive solidified material for deep disposal of high-level radioactive waste. The stability of borosilicate glass under irradiation is an important factor affecting the leakage of radioactive isotopes into the biosphere. In this study, three-component borosilicate glass (NBS) was irradiated by γ-rays at doses of 8 kGy and 800 kGy, respectively. The leaching behaviors of the irradiated samples at different absorbed doses were studied. The surface morphologies of the samples were analyzed using optical microscopy and scanning electron microscopy (SEM). The distributions of elements were analyzed using energy dispersive X-ray spectroscopy (EDS), and the elements in solution were characterized using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The results indicate that the irradiation effects on the leaching behavior of borosilicate glass occurs at certain thresholds. When the corrosion time is prolonged, the corrosion effect gradually covers the irradiation effect of the glass. Compared with 8 kGy irradiation, NBS glass samples exhibit more significant changes in elemental behavior under 800 kGy irradiation. After high-dose irradiation, the effect of corrosion on surface morphology is more significant than at low doses, and the element leaching rate of NBS glass is higher after 7 days of corrosion

Preparation of berberine magnetic nanoparticles and their inhibition of human gastric cancer BGC-823 cells

A new drug delivery system loaded with the drug berberine on carboxymethyl chitosan-coated magnetic nanoparticles (Fe3O4@CMCS-BBR) was prepared and characterized through x-ray diffraction, Fourier transform-infrared spectroscopy, a vibrating sample magnetometer, and transmission electron microscopy. By comparing the size of the uncoated nanoparticles (39.26 nm) and the size of the coated magnetite nanoparticles (73.75 nm), it was found that with the CMCS coating on the magnetite nanoparticles, the dispersion of the nanoparticle improved. The optimum pH testing showed a higher drug encapsulation of 51.23% and drug loading of 17.10% at a pH of 5.5 because of the better interaction of the NH3+ group with the negative functional groups of the CMCS. Furthermore, 85.89% of the drug was released within 72 h. The CCK-8 test results showed that Fe3O4@CMCS-BBR magnetic nanocomposites had good biocompatibility with gastric cancer BGC-823 cells and that Fe3O4@CMCS-BBR effectively inhibited the proliferation of cancer cells. The magnetic experimental results showed that Fe3O4@CMCS-BBR had good responsiveness to external magnetic fields and aggregated in the presence of a magnetic field. The results of targeting experiments showed that fluorescein isothiocyanate emitted a strong yellowish fluorescence in cells, which became stronger over time, and the killing effect on cancer cells became greater. The apoptosis results showed that the apoptosis rate induced by the magnetic nanodrug was 54.90%, indicating that the drug had a promoting effect on the apoptosis of BGC-823 cells

Development of a Quantitative Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of Novel Goose Parvovirus

An infectious disease characterized with short bills and protruding tongues has attacked to meat ducks in China since March 2015, which has caused ducks poor growth and enormous economic losses to duck industry of China. It was eventually proved to be caused by parvovirus after pathogen isolation and identification. As the genomic sequence analysis showed, this pathogen shared 90.8–94.6% of nucleotide identity with goose parvovirus (GPV), and it was called duck-origin novel goose parvovirus (N-GPV). In this study, a quantitative loop-mediated isothermal amplification (qLAMP) assay was developed for the rapid diagnosis of N-GPV. A set of four specific primers, two inner and two outer, were designed targeting at VP3 gene, which could be completed within 60 min at 65°C in water bath or on a real-time PCR instrument for quantitative analysis. Specificity test of LAMP assay showed that there was no cross-reactivity between N-GPV and other duck pathogens, and the detection limit of qLAMP assay was 1.0 × 102 copies/μL. The repeatability of this method was confirmed by inter-assay and intra-assay tests with variability ranging from 0.74 to 2.25%. The results have indicated that the qLAMP assay was a simple, rapid, accurate, sensitive, and specific method for detecting N-GPV, especially on field detection

Supergene Hydrous Sulfates in the Tuolugou Co-Au Deposit, Northern Qinghai–Tibet Plateau: Implications for Genetic Mechanism and Exploration

Supergene hydrous sulfate minerals form through the oxygenation and weathering of primary sulfides. In the Qinghai–Tibet Plateau region, with an alpine and dry environment, hydrous sulfate minerals oxidized from pyrite-bearing ore bodies provide important clues regarding the mineralization and environment. The Tuolugou sedimentary-exhalative (SEDEX) Co-Au deposit is located in the East Kunlun metallogenic belt of the northern Qinghai–Tibet Plateau in China. In the mining district, pyrite is the prevalent Co-hosting sulfide mineral, and is partially exposed on the surface to weathering and oxidation. Herein, we document the mineral assemblages in the supergene oxidation zone in the Tuolugou deposit, probe the genesis of supergene assemblage, and explore the implications for exploration. Three zones can be recognized in the oxidation zone of the Tuolugou deposit, including the outer zone (natrojarosite), intermediate zone (rozenite and aplowite), and inner zone (roemerite and melanterite). The mechanism of oxidation under aerobic and anaerobic conditions, as well as zoning with different oxidation degrees, are described in detail. Hydrous sulfates such as natrojarosite can be used as possible indicators of the exploration of albitite-related SEDEX deposit in this region

Serological and Pathogenic Analyses of Fowl Adenovirus Serotype 4 (FAdV-4) Strain in Muscovy Ducks

Hydropericardium hepatitis syndrome (HHS) is a lethal disease caused by Fowl adenovirus serotype 4(FAdV-4) that mainly infects 3- to 6-week-old broiler chicks. In 2015, an infectious disease characterized similar symptom to HHS in broilers outbroke in commercial duck flocks in Shandong province. FAdV-4 was isolated from naturally infected ducks and determined by polymerase chain reaction (PCR) amplification and DNA sequence analysis. In order to investigate the effect of FAdV-4 infection on muscovy ducks, we determined and characterized the FAdV-4 Isolate, and assessed its pathogenicity. In this study, HHS was respectively reproduced in 5-week-old muscovy duck by intramuscular injection and intranasal inoculation of allantoic fluid containing FAdV-4, ducks in the negative control group were inoculated with allantoic fluids of healthy duck embryos in the same manner. Clinical symptoms, gross and microscopic lesions, cytokines and antibodies, blood biochemical indices were detected and recorded for 12 days after infection. Typical hydropericardium and hepatitis was observed in experimental muscovy duck in the 3rd day post-inoculation (dpi). FAdV-4 can be replicated in tissues and cause pathological damage, especially in the liver and immune organs. Most of the immune-related cytokines and antibodies levels are up-regulated and then decreased, which may be caused by the initial infection and the normal immune response, later the virus caused the immunosuppression and led to the decrease of levels. To the best of our knowledge, this is the first systematic trial of the pathogenicity of FAdV-4 in muscovy ducks mainly based on the serological test, which will provide new insights into the study of the disease

The Application of EPMA in the Textural Characterization of Cryptomelane in the Xialei Manganese Deposit, Southwest Guangxi

BACKGROUND: OMS-2 has shown great significance in ion exchange, catalyst, energy and environment, but the research of natural OMS-2 mineral material cryptomelane is still lacking in the detailed characterization of the composition, structure and genetic research. Annulus and core-rim structures are representative in the structure of manganese oxide minerals. It is of great significance to clarify the mineral species and explore its composition characteristics, its origin and develop the application of manganese oxides. The Mn ore resource of Guangxi account for 23% of the manganese ore resource reserves in China. The Xialei Mn deposit located in Southwest Guangxi is the earliest super-large Mn deposit discovered in China, with an average grade of about 30% for the manganese oxide ore. OBJECTIVES: To explore the annulus and core-rim texture and its composition of cryptomelane in the Xialei Mn deposit.METHODS: Quantitative analysis and element mapping of EPMA and microscopy were carried out.RESULTS: The element intensity of the cryptomelane with annulus texture was Mn, K, Mg, Al, Zn, Ba, P, Fe in order of average from strong to weak. The average element intensity of the cryptomelane with core-rim texture was Mn, K, Ca, Mg, Zn, Ba, P, Fe from strong to weak. The K content gradually increased (2.31%-4.17%, 0.38-0.62 atoms per formula unit) from the middle to the rim of the cryptomelane, indicating K enrichment during oxidization and the stable status of Mn oxides.CONCLUSIONS: The change in the trend of K and Mn ions is the direct cause of the formation of the annulus and core-rim texture, reflecting the changes of oxidation environment. Potassium content gradually increases from the inner to outer zone, which may indicate the enrichment of potassium during the oxidation process, and also reflects manganese oxide gradually tending to the most stable state

Synthesis, Crystal Structure and Anti-Fatigue Effects of Some Benzamide Derivatives

A series of benzamide derivatives such as 1-(1,3-benzodioxol-5-ylcarbonyl) piperidine (1-BCP) were synthesized by the reaction of substituted benzoic acids with piperidine, morpholine or pyrrolidine using a novel method. The crystals of these benzamide derivatives were obtained by recrystallization. Structures of target and intermediate compounds were determined via FT-IR, 1H-NMR and elemental analysis and X-ray crystallography of select examples. The crystal structures of these compounds have potential applications to identify the binding site for allosteric modulators of the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor. The anti-fatigue effects of the benzamide derivatives in weight-loaded forced swimming mice were investigated in a swimming endurance capacity test used as an indicator of fatigue. The swimming times to exhaustion were longer in the b3, d3, and e3 groups than in the caffeine group (p < 0.05). In conclusion, b3, d3 and e3 enhanced the forced swimming capacity of mice. The mechanism of the anti-fatigue effects will be studied in the future