Petrography and mineral chemistry of 4 carbonaceous chondrites from the Grove Mountains, Antarctica

Petrography and mineral chemistry of four carbonaceous chondrites (GRV 020017, GRV 020025, GRV 021579, GRV 022459) collected from the Grove Mountains (GRV), Antarctica, were reported here. All four chondrites are unequilibrated, as indicated by well shaped chondrules and the chemical variations of olivine and low-C a pyroxene. The modal abundance ratio of matrix / chondrule are 2 (GRV 020017), 2.8 (GRV 020025), 1.2 (GRV 021579), 1 (GRV 022459). GRV 022459 has the largest chondrules(0.6-2.0mm). A total of 30 Ca-A l-rich inclusions were found in the four meteorites. Most inclusions were highly altered, with abundant phyllosilicates in the inclusions of GRV 020017 and GRV 020025. On the base of petrography and mineral chemistry, these chondrites are classified as CM2 (GRV 020017 and 020025), CO3(GRV 021579) and CV3(GRV 022459)

Weathering, shock metamorphism and type distribution patterns of 98 ordinary chondrites from the Grove Mountains, Antarctica

Petrography and mineral chemistry of ninety-eight ordinary chondrites from Grove Mountains (GRV), Antarctica, were presented and their. Weathering effect, shock metamorphism and type distribution patterns were discussed in this study. Among them, six are unequilibrated ordinary chondrites, including 3H3 and 3 L3; and 92 meteorites are equilibrated ordinary chondrites, including 24H-group (13H4, 10 H5, 1H6), 64 L-group (2 L4, 44 L5, 18 L6) and 4 LL-group (3 LL4, 1 LL5). Most GRV chondrites ( > 90% ) displayed minor weathering effect (W1 and W2). About half of the meteorites experienced severe shock metamorphism. They commonly contain shock-induced melt veins and pockets. These heavily shocked meteorites provide us with natural samples for study of high-pressure polymorphs of minerals. In addition, the Grove Mountains collection seems to have more abundant unequilibrated and L group ordinary chondrites compared to the US Antarctic meteorite collection which were mainly found a long the Transantarctic Mountains

Characterization of Periplasmic Protein BP26 Epitopes of Brucella melitensis Reacting with Murine Monoclonal and Sheep Antibodies

More than 35,000 new cases of human brucellosis were reported in 2010 by the Chinese Center for Disease Control and Prevention. An attenuated B. melitensis vaccine M5-90 is currently used for vaccination of sheep and goats in China. In the study, a periplasmic protein BP26 from M5-90 was characterized for its epitope reactivity with mouse monoclonal and sheep antibodies. A total of 29 monoclonal antibodies (mAbs) against recombinant BP26 (rBP26) were produced, which were tested for reactivity with a panel of BP26 peptides, three truncated rBP26 and native BP26 containing membrane protein extracts (NMP) of B. melitensis M5-90 in ELISA and Western-Blot. The linear, semi-conformational and conformational epitopes from native BP26 were identified. Two linear epitopes recognized by mAbs were revealed by 28 of 16mer overlapping peptides, which were accurately mapped as the core motif of amino acid residues 93DRDLQTGGI101 (position 93 to 101) or residues 104QPIYVYPD111, respectively. The reactivity of linear epitope peptides, rBP26 and NMP was tested with 137 sheep sera by ELISAs, of which the two linear epitopes had 65–70% reactivity and NMP 90% consistent with the results of a combination of two standard serological tests. The results were helpful for evaluating the reactivity of BP26 antigen in M5-90

Trends in Notifiable Infectious Diseases in China: Implications for Surveillance and Population Health Policy

This study aimed to analyse trends in notifiable infectious diseases in China, in their historical context. Both English and Chinese literature was searched and diseases were categorised according to the type of disease or transmission route. Temporal trends of morbidity and mortality rates were calculated for eight major infectious diseases types. Strong government commitment to public health responses and improvements in quality of life has led to the eradication or containment of a wide range of infectious diseases in China. The overall infectious diseases burden experienced a dramatic drop during 1975–1995, but since then, it reverted and maintained a gradual upward trend to date. Most notifiable diseases are contained at a low endemic level; however, local small-scale outbreaks remain common. Tuberculosis, as a bacterial infection, has re-emerged since the 1990s and has become prevalent in the country. Sexually transmitted infections are in a rapid, exponential growth phase, spreading from core groups to the general population. Together human immunodeficiency virus (HIV), they account for 39% of all death cases due to infectious diseases in China in 2008. Zoonotic infections, such as severe acute respiratory syndrome (SARS), rabies and influenza, pose constant threats to Chinese residents and remain the most deadly disease type among the infected individuals. Therefore, second-generation surveillance of behavioural risks or vectors associated with pathogen transmission should be scaled up. It is necessary to implement public health interventions that target HIV and relevant coinfections, address transmission associated with highly mobile populations, and reduce the risk of cross-species transmission of zoonotic pathogens

Doctor of Philosophy

dissertationA novel flash ironmaking technology is being developed at the University of Utah aimed at producing iron directly from magnetite concentrate (< 100 μm) using natural gas in a flash ironmaking reactor in the temperature range of 1150-1600 °C. In this process, natural gas is partially oxidized by oxygen to generate a reducing gas mixture of H2 and CO as well as providing the heat required for the reduction of iron oxide concentrate. Computational Fluid Dynamics (CFD) models, coupled with experimental results, were first used to accurately evaluate the kinetic parameters of iron oxide particle reduction by H2, CO, and H2+CO mixtures. The nucleation and growth rate expressions were found to best describe the reaction kinetics of the concentrate particles in the interested temperature range. The reduction rate was also found to be inversely proportional to the particle size for the higher temperature range, while no particle size effect for the lower temperature range was found. The rate equations for reduction by the H2+CO mixtures were also developed using the rate expressions by individual component gases. An enhancement factor which is a function of temperature and partial pressures of component gases was introduced to account for the synergistic effects due to the presence of CO. A three-dimensional CFD model was developed to simulate the gas particle flow pattern, heat transfer, and chemical reactions inside a laboratory scale flash. The obtained rate expressions from the first stage of this work were used and verified in the CFD iv simulation. The temperature profiles and the reduction degrees obtained from the simulation results satisfactorily agreed with the experimental measurements. As an intermediate step to the full industrial-scale flash ironmaking reactor, the design of a pilot-scale flash reactor was investigated in this work. The verified rate expressions and CFD models were used for the design of a reactor with a capacity of 100,000 tons/yr of metallic iron. The CFD simulation provided information such as temperature and species distribution, gas and particle flow patterns that are essential for the proper design of reactor desig

A Study of Shock-Metamorphic Features of Feldspars from the Xiuyan Impact Crater

Feldspar is the most abundant mineral in the Earth&rsquo;s crust and is widely distributed in rocks. It is also one of the most common minerals in meteorites. Shock-metamorphic features in feldspar are widely used to calibrate the temperature and pressure of shock events and can also provide clues for searching for impact craters on Earth. In this study, shocked alkali feldspars in the lithic breccia and suevite from Xiuyan Impact Crater were investigated using polarizing optical microscopes, Raman spectroscopy and electron microprobes to better constrain the shock history of this crater. For this study, feldspar grains occurring in gneiss clasts in the impact breccia and four shock stages were identified, e.g., weakly shocked feldspar, moderately shocked feldspar, strongly shocked feldspar, and whole rock melting. According to the shock classification system for alkali feldspar and felsic rocks, we estimated the shock pressure (SP) and post-shock temperature (PST) histories of these gneiss clasts. Weakly shocked feldspars display irregular fractures and undulatory extinction, and their shock stage is F-S2, which indicates that SP and PST are from ~5 to ~14 GPa and ~100 &deg;C, respectively. Moderately shocked feldspars show planar deformation features and are partially transformed into diaplectic glass, which indicates that the F-S5 shock stage of SP and PST is from ~32 to ~45 GPa and 300&ndash;900 &deg;C. Strongly shocked feldspars that occur as vesicular glass indicate a shock stage of F-S6, and the SP and PST are 45&ndash;60 GPa and 900&ndash;1500 &deg;C, respectively. The whole felsic rock melting occurs as mixed melt glass clast and belongs to the F-S7 stage, and SP and PST are &gt;60 GPa and &gt;1500 &deg;C, respectively

Corporate Governance Research in the Digital Economy: New Paradigms and Frontiers of Practice

 Digital technologies are increasingly changing the nature of competition and generating externalities that impact society. While the growth of a digital and sustainable economy may increase firm performance, these new trends also raise potential challenges for companies pertaining to corporate governance structures. In this paper, the impact of digitalization on corporate governance practices is discussed from the perspective of developing technologies and institutionalization, revealing potential effects, transformations, and steps to take. Our findings indicate that the development of the digital economy can facilitate enterprise digital transformation, enhance agency efficiency, and increase online media attention, thereby significantly promoting CSR performance for local firms. Digital transformation has an effect on the information quality and corporate governance, reducing agency costs, improving internal control, and attracting more analysts’ tracking, so as to build an effective trust mechanism between firms and the external market. The research conclusion of this article is helpful in analyzing the policy effectiveness of current corporate information disclosure regulations, and also provides a basis for the subsequent formulation of relevant disclosure policies. In addition to its theoretical significance, this paper also has important policy implications