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C31H37NO7, monoclinic, P21 (no. 4), a = 8.1269(1) Å, b = 11.0527(1) Å, c = 16.3586(2) Å, β = 97.973(1)°, V = 1455.19(3) Å3, Z = 2, Rgt (F) = 0.0467, wRref (F 2) = 0.1308, T = 293(2) K.

Polarons, quasiparticles from electron-phonon coupling, are crucial for material properties including high-temperature superconductivity and colossal magnetoresistance. However, scarce studies have investigated polaron formation in low-dimensional materials with phonon polarity and electronic structure transitions. In this work, we studied polarons of tellurene, composed of chiral Te chains. The frequency and linewidth of the A1 phonon, which becomes increasingly polar for thinner tellurene, change abruptly for thickness below 10 nanometers, where field-effect mobility drops rapidly. These phonon and transport signatures, combined with phonon polarity and band structure, suggest a crossover from large polarons in bulk tellurium to small polarons in few-layer tellurene. Effective field theory considering phonon renormalization in the small-polaron regime semiquantitatively reproduces the phonon hardening and broadening effects. This polaron crossover stems from the quasi-one-dimensional nature of tellurene, where modulation of interchain distance reduces dielectric screening and promotes electron-phonon coupling. Our work provides valuable insights into the influence of polarons on phononic, electronic, and structural properties in low-dimensional materials.

Porous cordierite ceramics were prepared with starch as pore-forming agent by solid-state method. The green bodies were sintered at 1,100–1,400 °C for 2 h. The characterization was focused on thermal analysis, phase evolution, sintering behavior, porosity and micro-structural changes. The results show that cordierite becomes the main crystallization phase at 1,200 °C. The shrinkage behavior shows the most obvious dependence on the sintering temperature and starch content, and it can be divided into three stages. Moreover, the open porosity increases with the increase of starch content, but the pore-forming effectivity decreases. Nevertheless, compared with the open porosity curves, the bulk density curves are more in line with the linear rule. The microphotographs show the densification process with the sintering temperature and the variation of pore connectivity with the starch content.

The highly porous cordierite ceramics were fabricated combining the merits of direct foaming and gelcasting method. The content of gum arabic had a great influence on the foaming capacity and the stability of the wet slurry foam. And the foaming capacity mainly affected the porosity while the stability mainly affected the pore size. The highest porosity of 90% was obtained at 0.4 wt.% gum arabic content and the smallest pore size and the most homogeneous pore distribution were arrived at 1.2 wt.% gum arabic content. As the sintering temperature increased, the porosity and pore size decreased but the uniformity of the pore distribution increased. Moreover, the thermal conductivity was mainly affected not only by the porosity, but also by the sintering degree of the cordierite substrate.

Abstract Background Antimicrobial resistance is an under-appreciated threat to public health in nations around the globe. With globalization booming, it is important to understand international patterns of resistance. If countries already experience similar patterns of resistance, it may be too late to worry about international spread. If large countries or groups of countries that are likely to leap ahead in their integration with the rest of the world – China being the standout case – have high and distinctive patterns of resistance, then a coordinated response could substantially help to control the spread of resistance. The literature to date provides only limited evidence on these issues. Methods We study the recent patterns of antibiotic resistance in three geographically separated, and culturally and economically distinct countries – China, Kuwait and the United States – to gauge the range and depth of this global health threat, and its potential for growth as globalization expands. Our primary measures are the prevalence of resistance of specific bacteria to specific antibiotics. We also propose and illustrate methods for aggregating specific "bug-drug" data. We use these aggregate measures to summarize the resistance pattern for each country and to study the extent of correlation between countries' patterns of drug resistance. Results We find that China has the highest level of antibiotic resistance, followed by Kuwait and the U.S. In a study of resistance patterns of several most common bacteria in China in 1999 and 2001, the mean prevalence of resistance among hospital-acquired infections was as high as 41% (with a range from 23% to 77%) and that among community- acquired infections was 26% (with a range from 15% to 39%). China also has the most rapid growth rate of resistance (22% average growth in a study spanning 1994 to 2000). Kuwait is second (17% average growth in a period from 1999 to 2003), and the U.S. the lowest (6% from 1999 to 2002). Patterns of resistance across the three countries are not highly correlated; the most correlated were China and Kuwait, followed by Kuwait and the U.S., and the least correlated pair was China and the U.S. Conclusion Antimicrobial resistance is a serious and growing problem in all three countries. To date, there is not strong international convergence in the countries' resistance patterns. This finding may change with the greater international travel that will accompany globalization. Future research on the determinants of drug resistance patterns, and their international convergence or divergence, should be a priority.

Phosphorus (P) is vital for the growth of crops, and its absorption efficiency is closely linked to the traits of the plants. Further research is needed to understand how vegetable crops adjust to changes in P availability and how their root morphology and physiology are affected by high P levels in the shoots. In this study, eight Chinese cabbage (Brassica rapa pekinensis) genotypes were grown in a culture room under 0, 25, 50, 100, 150, 300, 600, 900, and 1200 mg kg−1 concentrations of P to evaluate root responses in order to define various adaptive strategies in relation to P acquisition. We selected high-PE and low-PE Chinese cabbage in order to identify how different P efficiency groups responded to P supply and shoot P concentration. P supply level and shoot P concentration significantly affected growth. With the increase in the P supply level, the growth variable characteristics of Chinese cabbage first increased and then decreased or increased first and then stabilized. But it was found that P300 was the most suitable level for Chinese cabbage growth. At the same P supply level, high-PE cabbages had higher shoot dry weight and P absorption capacity, stronger root traits, and higher plasticity as compared to low-PE cabbages. The optimal shoot P concentration is 2.1 mg g−1 and 1.7 mg g−1 for low- and high-PE cabbages, respectively. The root morphological traits performed greatly when the shoot P concentration was at the optimal concentration. The low-PE cabbages had greater shoot growth traits, and high-PE cabbages had higher root dry weight and P absorption. This study offers valuable insights to improve P management by analyzing the relationships between soil P dynamics and root processes in the cultivation of Chinese cabbage. [ABSTRACT FROM AUTHOR]

This paper proposes a stochastic linear parameter-varying (LPV) model approach to design a state feedback controller for three-phase, two-level inverters. To deal with the parameter changes, stochastic noise, and delays faced by the inverter, it is modeled as a stochastic LPV system with time delay. Stability analysis and control synthesis are conducted for the LPV system. With parameter-dependent Lyapunov functionals, a condition of sufficient stability for asymptotical mean-square stability is obtained. In addition, the slack matrix technique is employed to improve the feasibility and reduce the conservatism of the conditions. The obtained theoretical results are applied to the three-phase, two-level inverter, whose currents are treated as state variables and are controlled to reach the equilibrium point. The simulation results validate the effectiveness of the proposed theories and demonstrate the advantages of using the slack matrix. [ABSTRACT FROM AUTHOR]