Processing outcomes of the AFM probe-based machining approach with different feed directions

We present experimental and theoretical results to describe and explain processing outcomes when producing nanochannels that are a few times wider than the atomic force microscope (AFM) probe using an AFM. This is achieved when AFM tip-based machining is performed with reciprocating motion of the tip of the AFM probe. In this case, different feed directions with respect to the orientation of the AFM probe can be used. The machining outputs of interest are the chip formation process, obtained machined quality, and variation in the achieved channel depth. A three-sided pyramidal diamond probe was used under load-controlled conditions. Three feed directions were first investigated in detail. The direction parallel to and towards the probe cantilever, which is defined as “edge forward”, was then chosen for further investigation because it resulted in the best chip formation, machining quality, and material removal efficiency. To accurately reveal the machining mechanisms, several feed directions with different included angles for the pure edge-forward direction were investigated. Upon analysis of the chips and the machined nanochannels, it was found that processing with included angles in the range 0–30° led to high-quality channels and high material-removal efficiency. In this case, the cutting angles, such as the rake angle, clearance angle, and shear angle, have an important influence on the obtained results. In addition, a machining model was developed to explain the observed machined depth variation when scratching in different feed directions

Possible Impact of Climate Change on the Quality of Apples from the Major Producing Areas of China

Meteorological conditions are important environmental factors affecting apple quality. To understand the possible impact of climate change on the apple quality of the major producing areas in China and assess the quality of major apple species (e.g., Fuji, Ralls, and Golden Delicious), we studied the variation trends and abrupt change characteristics of six major climate factors affecting seven physicochemical indices of apple quality across five apple regions, including the Loess Plateau, Bohai Bay, the Old Course of the Yellow River, Southwest Highlands, and Xinjiang, using statistical methods, meteorological indices, and the ArcGIS analysis tool based on the meteorological observational data from 1961 to 2013. The results show that the spatial and temporal distributions of annual average temperature, annual sunshine duration, average summer temperature, summer diurnal temperature range, and average summer relative humidity all significantly changed (except annual precipitation) and that abrupt changes occurred. The annual temperatures and average summer temperatures in the Loess Plateau apple region and the Liaoning producing region of Bohai Bay increased within optimal ranges. In addition, for high-value regions, the hours of sunshine decreased, helping to improve the fruit shape index, sugar-acid ratio, and vitamin C (VC) content. Relatively high temperatures continued to increase to high values which remained lower than the optimal upper limit; the diurnal temperature range continued to decrease; and the sunshine hours significantly decreased within the optimal range, which might have worsened fruit hardness, soluble sugar, and peel anthocyanin in the producing regions of Southwest Shandong of Bohai Bay, Southeast Hebei of the Old Course of the Yellow River, Northern Anhui, and Jiangsu. In the production regions of the Yun-Gui plateau in the Southwest highlands, increased summer temperature and the diurnal temperature range were both within the optimal ranges, which might have helped to reduce fruit hardness and increase soluble sugar content. However, continuously increased temperature and reduced sunshine might have worsened the apple shape index and fruit coloring. In the Xinjiang apple-producing region, the climate became warmer and more humid with reduced daily sunshine hours, which might have improved the exterior quality of apples and reduced fruit hardness. Thus, the climate changes over the last 50 years have positively affected the seven apple quality physicochemical properties in the Loess Plateau and Xinjiang, whereas the impacts on the different indices of apple quality in the other apple-producing regions are less coherent. In general, climate change has significantly affected the apple quality of the major production regions in China. Corresponding scientific measures are needed to assure high apple quality to increase the income of farmers in the future

Possible Impact of Climate Change on the Quality of Apples from the Major Producing Areas of China

Meteorological conditions are important environmental factors affecting apple quality. To understand the possible impact of climate change on the apple quality of the major producing areas in China and assess the quality of major apple species (e.g., Fuji, Ralls, and Golden Delicious), we studied the variation trends and abrupt change characteristics of six major climate factors affecting seven physicochemical indices of apple quality across five apple regions, including the Loess Plateau, Bohai Bay, the Old Course of the Yellow River, Southwest Highlands, and Xinjiang, using statistical methods, meteorological indices, and the ArcGIS analysis tool based on the meteorological observational data from 1961 to 2013. The results show that the spatial and temporal distributions of annual average temperature, annual sunshine duration, average summer temperature, summer diurnal temperature range, and average summer relative humidity all significantly changed (except annual precipitation) and that abrupt changes occurred. The annual temperatures and average summer temperatures in the Loess Plateau apple region and the Liaoning producing region of Bohai Bay increased within optimal ranges. In addition, for high-value regions, the hours of sunshine decreased, helping to improve the fruit shape index, sugar-acid ratio, and vitamin C (VC) content. Relatively high temperatures continued to increase to high values which remained lower than the optimal upper limit; the diurnal temperature range continued to decrease; and the sunshine hours significantly decreased within the optimal range, which might have worsened fruit hardness, soluble sugar, and peel anthocyanin in the producing regions of Southwest Shandong of Bohai Bay, Southeast Hebei of the Old Course of the Yellow River, Northern Anhui, and Jiangsu. In the production regions of the Yun-Gui plateau in the Southwest highlands, increased summer temperature and the diurnal temperature range were both within the optimal ranges, which might have helped to reduce fruit hardness and increase soluble sugar content. However, continuously increased temperature and reduced sunshine might have worsened the apple shape index and fruit coloring. In the Xinjiang apple-producing region, the climate became warmer and more humid with reduced daily sunshine hours, which might have improved the exterior quality of apples and reduced fruit hardness. Thus, the climate changes over the last 50 years have positively affected the seven apple quality physicochemical properties in the Loess Plateau and Xinjiang, whereas the impacts on the different indices of apple quality in the other apple-producing regions are less coherent. In general, climate change has significantly affected the apple quality of the major production regions in China. Corresponding scientific measures are needed to assure high apple quality to increase the income of farmers in the future

Understanding Alkali Cation-Assisted Ring-Opening Polymerization of Macrocyclic Carbonate: Kinetics and Thermodynamics

Control over polymerization thermodynamics and kinetics enables the generation of polymers with on-demand properties. This is exemplified by the ring-opening polymerization of tetraethylene glycol carbonate (4EGMC) using an alkali cation (M+)-based binary catalytic system at ambient temperature. By introducing a guanidine catalyst [(1,5,7-triazabicyclo[4.4.0]dec-5-ene), TBD], the alkali cation-assisted ring-opening polymerization of macrocyclic carbonate was ca. 120–270 times faster than the reaction without an alkali cation, M+ (0.16–0.36 min–1 with M+ vs 0.001 min–1 without M+). Moreover, the interaction between 4EGMC and M+ led to an increase in the ring strain, supported by both bench experiments and computational simulations. This interaction altered the driving force of polymerization from the change of entropy to enthalpy, which revealed the pivotal role of alkali cations in regulating the ring-opening polymerization of macrocyclic carbonate

Understanding Alkali Cation-Assisted Ring-Opening Polymerization of Macrocyclic Carbonate: Kinetics and Thermodynamics

Control over polymerization thermodynamics and kinetics enables the generation of polymers with on-demand properties. This is exemplified by the ring-opening polymerization of tetraethylene glycol carbonate (4EGMC) using an alkali cation (M+)-based binary catalytic system at ambient temperature. By introducing a guanidine catalyst [(1,5,7-triazabicyclo[4.4.0]dec-5-ene), TBD], the alkali cation-assisted ring-opening polymerization of macrocyclic carbonate was ca. 120–270 times faster than the reaction without an alkali cation, M+ (0.16–0.36 min–1 with M+ vs 0.001 min–1 without M+). Moreover, the interaction between 4EGMC and M+ led to an increase in the ring strain, supported by both bench experiments and computational simulations. This interaction altered the driving force of polymerization from the change of entropy to enthalpy, which revealed the pivotal role of alkali cations in regulating the ring-opening polymerization of macrocyclic carbonate

Modulation of Kir4.1 and Kir5.1 by hypercapnia and intracellular acidosis

CO2 chemoreception may be mediated by the modulation of certain ion channels in neurons. Kir4.1 and Kir5.1, two members of the inward rectifier K+ channel family, are expressed in several brain regions including the brainstem. To test the hypothesis that Kir4.1 and Kir5.1 are modulated by CO2 and pH, we carried out experiments by expressing Kir4.1 and coexpressing Kir4.1 with Kir5.1 (Kir4.1-Kir5.1) in Xenopus oocytes. K+ currents were then studied using two-electrode voltage clamp and excised patches.Exposure of the oocytes to CO2 (5, 10 and 15 %) produced a concentration-dependent inhibition of the whole-cell K+ currents. This inhibition was fast and reversible. Exposure to 15 % CO2 suppressed Kir4.1 currents by ∼20 % and Kir4.1-Kir5.1 currents by ∼60 %.The effect of CO2 was likely to be mediated by intracellular acidification, because selective intracellular, but not extracellular, acidification to the measured hypercapnic pH levels lowered the currents as effectively as hypercapnia.In excised inside-out patches, exposure of the cytosolic side of membranes to solutions with various pH levels brought about a dose-dependent inhibition of the macroscopic K+ currents. The pK value (-log of dissociation constant) for the inhibition was 6.03 in the Kir4.1 channels, while it was 7.45 in Kir4.1-Kir5.1 channels, an increase in pH sensitivity of 1.4 pH units.Hypercapnia without changing pH did not inhibit the Kir4.1 and Kir4.1-Kir5.1 currents, suggesting that these channels are inhibited by protons rather than molecular CO2.A lysine residue in the N terminus of Kir4.1 is critical. Mutation of this lysine at position 67 to methionine (K67M) completely eliminated the CO2 sensitivity of both the homomeric Kir4.1 and heteromeric Kir4.1-Kir5.1.These results therefore indicate that the Kir4.1 channel is inhibited during hypercapnia by a decrease in intracellular pH, and the coexpression of Kir4.1 with Kir5.1 greatly enhances channel sensitivity to CO2/pH and may enable cells to detect both increases and decreases in PCO2 and intracellular pH at physiological levels

Legislative Documents

Also, variously referred to as: Senate bills; Senate documents; Senate legislative documents; legislative documents; and General Court documents