ALBERT

Description: Motion control of a single molecule through a solid-state nanopore offers a new perspective on detecting and analyzing single biomolecules. Repeat recapture of a single DNA molecule reveals the dynamics in DNA translocation through a nanopore and may significantly increase the signal-to-noise ratio for DNA base distinguishing. However, the transient current at the moment of voltage reversal prevents the observation of instantly recaptured molecules and invalidates the continuous DNA ping-pong control. We performed and analyzed the DNA translocation and recapture experiment in a silicon nitride solid-state nanopore. Numerical calculation of molecular motion clearly shows the recapture dynamics with different delay times. The prohibited time when the data acquisition system is saturated by the transient current is derived by equivalent circuit analysis and finite element simulation. The COMSOL simulation reveals that the membrane capacitance plays an important role in determining the electric field distribution during the charging process. As a result of the transient charging process, a non-constant driving force pulls the DNA back to nanopores faster than theoretically predicted. The observed long time constant in the transient current trace is explained by the dielectric absorption of the membrane capacitor.

Description: Plants have considerable hydrological and mechanical impacts on soil. However, there are lack of documentation and limited understanding on the hydrological and mechanical impacts of tropical legume trees. Therefore, this study was aimed to investigate the hydrological and mechanical properties of three selected legume plants, Leucaena leucocephala , Adenanthera pavonina and Peltophorum pterocarpum . Regarding hydrological aspect, the study results indicated that soil on which the L. leucocephala was grown had the highest transpiration rate, water absorption rate (WAR) and soil matric suction (SMS). In terms of mechanical characteristics, L. leucocephala exhibited the highest root tensile strength and cellulosic components in the root. Interestingly, L. leucocephala also showed a higher root biomass, root length and fine roots than A . pavonina and P. pterocarpum. The leaf area index (LAI) strongly correlated with SMS ( R 2  = 0.74), indicating that high LAI improved SMS. The high root tensile strength and fine roots of L. leucocephala make this species special for growing as a soil reinforcing plant. Overall results suggested that L. leucocephala exhibited outstanding hydrological and mechanical properties and can be a potential plant for the soil reinforcement program.

Description: We presented an integrated software system for analyzing nanopore data. This self-developed software provided rapid processes for accurate location, classification, and evaluation of every individual blockade. Using the proposed software, statistical analysis could be achieved easily and conveniently. The results of β -Amyloid 42 demonstrated that our data process could rapidly extract duration time and current amplitudes. In addition, our data process could accurately carry out statistical fittings.

Description: A novel phenol-linked bis(imidazolium) salt, H 3 LCl 2 (L =  O -4-C(CH 3 ) 3 -C 6 H 2 -2,6-di[CH 2 {C(NCHCHNAr)}] 2 , Ar = 2,6-diisopropylphenyl, 1 ), was designed and used to prepare an ionic iron(III) complex [H 2 L][FeCl 4 ] ( 2 ). Complex 2 was a highly efficient catalyst for aryl Grignard cross-coupling of alkyl chlorides bearing β-hydrogens. Furthermore, complex 2 was reusable and could be reused in at least eight times without significant loss in catalytic activity.

Description: Vertically aligned TiO 2 nanotube arrays (~8 μm long, ~110 nm wide) have been fabricated through anodic oxidation of Ti-metal sheet in fluoride-containing electrolyte. By changing the volume ratio of ethylene glycol and diethylene glycol in the electrolyte, TiO 2 nanotube arrays with different tube-to-tube lateral spacing, i.e., closely packed, just separated, and fully separated, have been synthesized and applied as photoanodes for dye-sensitized solar cells (DSSCs). Photovoltaic efficiency of 2.99 %, 3.34 %, and 3.44 % has been obtained for DSSCs based on the closely packed, just separated, and fully separated TiO 2 nanotube arrays, respectively, illustrating the effect of tube-to-tube lateral spacing of TiO 2 nanotube arrays on the performances of DSSCs. It is suggested that fully separated TiO 2 nanotube arrays are beneficial to the conversion efficiency of DSSCs due to higher dye loading and faster electron transfer.

Description: Vegetation phenology is an important indicator of climate change impacts on the seasonal dynamics of the biosphere. However, little is known about the influence of elevation on spring phenological sensitivity to temperature in an alpine ecosystem. Based on remotely sensed land surface phenology and temperature data from 2001 to 2010, this study investigated the rate of spring phenological change of the Tibetan Plateau (TP) grasslands in response to interannual temperature variations at different elevations. Results suggest that spring phenology in the TP grasslands exhibits a stronger response to changes in temperature at higher elevations than at lower ones. In particular, spring phenology advanced by 1–2 days in response to a 1 °C increase in May average temperature at elevations from 3,000 to 3,500 m, while the rate was up to 8–9 days/°C at 5,000–5,500 m. Analysis using accumulated growing degree days (AGDD) from January 1 through May 31 showed the same general trend with increased elevation associated with increased sensitivity (as measured by phenological change per unit of AGDD change). Such temperature sensitivity gradients in the TP grasslands could be partly explained by the growth efficiency hypothesis which suggests that vegetation adapted to colder climates likely requires less heat energy for the onset of growing season and vice versa in warmer climates. Furthermore, accumulated growing degree days from January 1 to the greenup date were found to decrease with increasing elevations, which provided evidence to support the applicability of the growth efficiency hypothesis in an alpine grassland ecosystem.

Description: A gravity network with 302 observation points has been established in the western Sichuan Foreland Basin (SFB) to explore Bouguer gravity anomalies (BGAs). Our observational results reveal that the BGAs are negative as a whole, with a maximum value of −220 mGal (10 −5 m s −2 ) at the northwest region of the study area. The real Moho depths beneath the SFB revealed by BGA data change smoothly from 39.5 km in the southeast to 43.7 km in the northwest of the monitoring region. However, the isostatic ones deduced from Airy isostatic model and topographical data vary approximately 39.5–42.0 km. The maximum differences of 2.7 km between the real and isostatic Moho depths are found near the seismic gap between the M 8.0 Wenchuan and M 7.0 Lushan earthquakes, where the crust is in the greatest isostatic imbalance of the monitoring region. Analysis of the isostatic state indicates that the deep dynamic environment near the seismic gap between these two earthquakes indicates an M  ≥ 7.0 earthquake in the future. This study indicates that we can use isostasy as a potential approach to study the dynamic process of crustal material movement and to analyze regional potential seismic risks.

Description: Climate change is considered a top threat to biodiversity, but the relative roles of contemporary climate versus the rate of climate change in determining spatial patterns of biodiversity are far from clear. China has a very diverse flora and harbors a high percentage of endemic species, but the mechanisms underlying spatial patterns of plant endemism are poorly understood. This study explores the geographical patterns of a representative sample of 555 endemic seed plant species at the scale of 0.5° latitude × 0.5° longitude. Ordinary least squares and spatial autoregressive models were compared to assess the relationship between richness of endemics and the rate of climate change in the past century, as well as a group of contemporary climate variables. In China, a high level of endemism was associated with high elevation and low rate of climate change. However, contemporary climate had a stronger impact than climate change velocity in the past century on endemic species richness patterns. Specifically, mean annual precipitation and annual range of temperature were important contemporary climatic factors. The rate of change of annual mean temperature, but not that of annual precipitation, also significantly contributed to the spatial pattern of plant endemic species richness. We found no significant relationship between topographic variation and endemic species richness, while temperature variability at multiple time scales was strongly correlated with the species richness pattern. Future work should consider the direction of climate change and incorporate higher-resolution data.

Description: Widespread lakes on the Tibetan Plateau (TP) are valuable archives for investigating climate and environment changes, which could provide essential information on the mechanisms of past climate changes on the TP and their interaction with the global climate systems. However, there is a lack of in-depth investigation of modern limnological processes in the Tibetan lakes, which hampers the understanding of paleolimnological records and lake ecosystem succession. In this study, we performed continuous temperature monitoring at two lakes, Bangong Co, a freshwater lake in the western TP, and Dagze Co, a brackish lake in the central TP, in order to characterize the patterns of seasonal temperature variability, stratification, and mixing. Temperature data for an entire hydrological year demonstrate that Bangong Co is a dimictic lake and that Dagze Co is a meromictic lake. The higher salinity in the deep water at Dagze Co prevents the lake from overturning completely, and this finding is supported by simulations using a physical limnological model Lake Analyzer. Continuous lake water temperature monitoring provides fundamental data for classifying Tibetan lakes, as well as the hydrological basis for understanding their paleolimnological records and ecosystem succession.

Description: An 18-year long (1993–2011) comprehensive dataset of snow and meteorological variables from Col de Porte, France is used to analyze the variation of shortwave broadband albedo with elapsed time after snowfalls (snow aging) during each snow season. The effects of air temperature, snow surface temperature and snow depth on snow albedo are investigated. An index based on the accumulation of air temperature over several consecutive days with daily mean higher than 2.5 °C is proposed to divide each snow-covered period into a dry and the following wet snow season when this index reaches 18 °C. The results indicate that snow surface albedo decreases exponentially with time in both dry and wet snow seasons. Snow albedo reduction with snow aging is small at low surface temperature and the reduction rate increases with the rise of surface temperature. However, the reduction rate is widely scattered within the observed range of temperature, implying a loose relationship between snow albedo and snow surface temperature. Snow albedo in wet snow season is generally smaller and decreases faster than in dry snow season. For Col de Porte site, snow depths to effectively mask the underlying surface are 21 and 33 cm in dry and wet snow season respectively.