One-dimensional growth of zinc oxide nanostructures from large micro-particles in a highly rapid synthesis

Large and irregularly-shaped zinc oxide (ZnO) micro-particles commonly found in a high-temperature vapor-phase process known as the catalyst-free combust-oxidized mesh (CFCOM) process, play a crucial role as nucleation hosts for ZnO one-dimensional (1D) nanostructures, especially nanometric wires and rods. Nanowires and nanorods tend to grow from the hillocks of the large micro-particles whereby these hillocks serve as nucleation sites for the acicular structures. Nanowires with aspect ratios exceeding 5 are the most common 1D structures that grow from pillar-like hillocks, while triangular hillocks are probable nucleation hosts for nanorods. The ZnO nanostructures possess a polycrystalline nature with photoluminescent emission in the UV band-edge and visible regimes. A novel and non-destructive electrical resistance measurement method is introduced in that the 1D ZnO nanostructures exhibited very high GΩ resistance that is over five times higher than that of commercial ZnO. A growth model is proposed to offer a probable explanation for the fascinating rapid growth of 1D nanostructures originating from large ZnO micro-particles. The ZnO particles in this work were synthesized using 5-ton industrial furnaces via a university-industry joint effort.     

中国油菜单产增长要素贡献率分析

运用因子分析技术将影响中国油菜单产的众多因素综合为物质费用、劳动力、政策制度和结构与灾害四大因素,并利用Cobb-Douglas型生产函数模型分别测算了四大因素在中国油菜单产增长中的贡献率。根据1990～2004年间的数据计算,物质费用对中国油菜单产增长的贡献率最大,其次是劳动力和政策制度,而同期结构与灾害因子对单产有负向影响。     

The Complexity of Public Attitudes Toward Compact Development

Problem: The future of compact development depends in part on understanding and shaping the public's attitudes toward it. Previous studies have suggested life cycle, socioeconomic, attitudinal, and ideological dimensions to preferences regarding development patterns, but rarely have all of these factors been examined systematically across a broad, generalizable sample of respondents.

Purpose: To examine public attitudes toward compact development, we asked survey respondents to weigh four important tradeoffs between compact and sprawling growth. We assess the relative influence of a variety of individual characteristics on these attitudes.

Methods: We use results from two large-scale, randomized telephone surveys, one conducted in California in 2002 and the other in four other southwestern states in 2007. Using logistic regression, we assess which personal characteristics are associated with stated preferences regarding compact development, and illustrate their degree of influence.

Results and conclusions: Support for the compact development alternatives is significant, in some cases exceeding support for traditional, decentralized suburban patterns. However, question wording appears to matter considerably, and individuals’ beliefs about different facets of compact development are often inconsistent. Although race, income, age, and the presence of children in the household are strongly associated with some views on the four tradeoffs, only political ideology is consistently associated with opposition to compact development.

Takeaway for practice: The significant support evident for compact development may not translate into actual housing choices unless local governments and lenders do more to support the production of such housing and neighborhood environments. If, as our results suggest, a major constituency for transit-oriented and mixed-use projects is low income residents, renters, and minorities, then well crafted urban infill projects that take into account the needs of these groups will help fulfill the potential of smart growth. Advocates might also frame compact development to appeal more to political conservatives.

Research support: The 2002 survey was conducted by the Public Policy Institute of California, with financial support from the William and Flora Hewlett Foundation, James Irvine Foundation, and David and Lucille Packard Foundation. The 2007 survey was conducted and supported by the Institute for Social Science Research at Arizona State University. All views expressed are solely those of the authors, not these organizations.     

Optimal Growth Conditions for Selective Ge Islands Positioning on Pit-Patterned Si(001)

We investigate ordered nucleation of Ge islands on pit-patterned Si(001) using an original hybrid Kinetic Monte Carlo model. The method allows us to explore long time-scale evolution while using large simulation cells. We analyze the possibility to achieve selective nucleation and island homogeneity as a function of the various parameters (flux, temperature, pit period) able to influence the growth process. The presence of an optimal condition where the atomic diffusivity is sufficient to guarantee nucleation only within pits, but not so large to induce significant Ostwald ripening, is clearly demonstrated.     

Detection of EGFR on living human gastric cancer BGC823 cells using surface plasmon resonance phase sensing

Label-free and real-time information acquisition of molecular phenotype and its function on living cells plays a significant role in disease diagnosis and drug development. In this paper, SPR phase sensing was applied to monitor the interactions between EGFR antibody, EGFR1, and membrane proteins EGFR on living human gastric cancer BGC823 cells. When 50 μg/mL EGFR1 was added onto the fixed cells chip and the living cells chip, a significant difference in the binding amount could be observed from the immunofluorescence images. Quantitative results were obtained by following SPR detection, which were 722 RU and 438 RU, respectively. On the same living cells chip, SPR detection also showed markedly different results of cellular responses when it was stimulated by EGFR1 at different concentrations, such as adhesion and/or morphology variation, revealing the EGFR1's cytotoxic effect on the BGC823 cells. The results demonstrate SPR phase sensing is capable of real-time detection of molecular interactions and cellular responses on living cells, and suggest that further studies on the mechanism and the technique may allow SPR sensing become a powerful tool not only for the basic research of cell biology, but also for medical diagnosis and drug development.     

Energy consumption-economic growth relationship and carbon dioxide emissions in China

This paper applies the panel unit root, heterogeneous panel cointegration and panel-based dynamic OLS to re-investigate the co-movement and relationship between energy consumption and economic growth for 30 provinces in mainland China from 1985 to 2007. The empirical results show that there is a positive long-run cointegrated relationship between real GDP per capita and energy consumption variables. Furthermore, we investigate two cross-regional groups, namely the east China and west China groups, and get more important results and implications. In the long-term, a 1% increase in real GDP per capita increases the consumption of energy by approximately 0.48–0.50% and accordingly increases the carbon dioxide emissions by about 0.41–0.43% in China. The economic growth in east China is energy-dependent to a great extent, and the income elasticity of energy consumption in east China is over 2 times that of the west China. At present, China is subject to tremendous pressures for mitigating climate change issues. It is possible that the GDP per capita elasticity of carbon dioxide emissions would be controlled in a range from 0.2 to 0.3 by the great effort.     

Vapor growth of CdSe:Cr and CdS:Cr single crystals for mid-infrared lasers

Single crystals of CdSe:Cr and CdS:Cr with the doping level up to 10¹⁹ cm⁻³ were grown by a vapor phase contact-free technique. An efficient room-temperature pulsed and continuous wave (CW) lasing with the CdSe:Cr crystal was achieved. First a pulsed lasing with the CdS:Cr crystal was also demonstrated. The slope efficiency on the absorbed energy was as high as 46.5% for Cr²⁺:CdSe and 39% for Cr²⁺:CdS lasers. Using an intra-cavity prism, the Cr²⁺:CdSe laser wavelength was continuously tuned from 2.26 to 3.61 μm while the Cr²⁺:CdS laser from 2.2 to 3.3 μm. For the laser wavelength, the crystal passive loss coefficient was estimated to be smaller than 0.045 cm⁻¹ for CdSe:Cr crystals and 0.039 cm⁻¹ for CdS:Cr crystals. For the Cr²⁺:CdSe laser, the CW output power up to 1.07 W was achieved.     

Effect of silica doping on the densification and grain growth in zinc oxide

The ability of silica (SiO₂) in controlling the densification and grain growth behavior of nano crystalline zinc oxide (ZnO) has been systematically studied. It has been observed that SiO₂ acts as a sintering inhibitor in the ZnO–SiO₂ system up to 4 wt.% limiting value beyond which densification behavior of the system remains almost unchanged, especially above 1100 °C. The addition of SiO₂ to ZnO retards grain growth which in turn results a finer ultimate grain size as compared to the undoped ZnO. However, stabilization in grain size occurs at ≥4 wt.% SiO₂ addition. It has been observed that SiO₂ incorporation changes the grain growth mechanism up to 4 wt.% addition, beyond which no remarkable changes was noticed. The grain growth (n) shows distinctly different slopes as a function of sintering time for the SiO₂ doped ZnO systems than undoped ZnO. The different slopes tend to indicate that different diffusion mechanisms and probably the formation of a secondary phase (Zn–Si–O) at the grain boundary control the densification and grain growth. The thermal expansion coefficient of the system has been found to decrease substantially beyond 4 wt.% SiO₂ addition to ZnO.     

Identification of ubiquitin in bovine milk and its growth inhibitory effects on human cancer cell lines

Bovine milk is associated with improved health and reduced risk of several diseases, among them cancer. Milk is a complex mixture of known and unknown components. The components and the mechanisms that contribute to the cancer-preventive effects are largely unknown. We set out to find new peptides in milk and identified ubiquitin (Ub) using matrix-assisted laser desorption ionization-time of flight mass spectrometry and Western blot. Using quantitative Western blot, we estimated the Ub concentration to be about 0.003 μmol/L in milk. We then decided to investigate the effect of treating human colon cancer CaCo-2 cells with Ub, using higher concentrations than in milk. CaCo-2 cells treated with 0.02 to 2.0 μmol/L Ub showed significantly decreased proliferation compared with untreated control cells. A higher growth inhibitory effect than in CaCo-2 cells was found in the neuroblastoma cell line SH-SY5Y treated with 0.02 to 0.2 μmol/L Ub. A bromodeoxyuridine DNA flow cytometric method was used to study cell cycle kinetics in Ub-treated CaCo-2 cells. The data point toward a prolongation of the G₁ phase. The levels of several cell cycle regulatory proteins were affected. Our data point to Ub possibly being one of the components in milk reducing the risk of cancer.     

A new approach for multiple attribute group decision making with interval-valued intuitionistic fuzzy information

This paper proposes a novel method for multiple attribute group decision making (MAGDM) with interval-valued intuitionistic fuzzy information. The interval-valued intuitionistic fuzzy numbers of each expert preference matrix are first mapped into two dimensions. Thus, the values of each membership degree and non-membership degree are considered as points in the two-dimensional representation. Moreover, the distance between the points represents the variance among the different experts preferences. The preference points of the same character are considered as a point set. We employ the plant growth simulation algorithm (PGSA) to calculate the optimal rally points of every point set, the sum of whose Euclidean distances to other given points is minimal, and these optimal rally points reflect the preferences of the entire expert group. These points are used to establish an expert preference aggregation matrix. Suitable points from the matrix are chosen to constitute an ideal point matrix, a projection method is employed to calculate the sum of its Euclidean distance to the expert preference aggregation matrix, and the score of each alternative is evaluated. Finally, the overall ranking of alternatives is obtained. In addition, this study develops a process to evaluate the pros and cons of different aggregation methods. Two typical examples are presented to illustrate the feasibility and effectiveness of the proposed approach.