19 research outputs found
MicroSPE-nanoLC-ESI-MS/MS Using 10-μm-i.d. Silica-Based Monolithic Columns for Proteomics
Ultratrace LC/MS Proteomic Analysis Using 10-μm-i.d. Porous Layer Open Tubular Poly(styrene−divinylbenzene) Capillary Columns
Synthesis and characteristics of the human serum albumin-triazine chiral stationary phase
The Potential Utility of Satellite Soil Moisture Retrievals for Detecting Irrigation Patterns in China
Climate change and anthropogenic activities, including agricultural irrigation have significantly altered the global and regional hydrological cycle. However, human-induced modification to the natural environment is not well represented in land surface models (LSMs). In this study, we utilize microwave-based soil moisture products to aid the detection of under-represented irrigation processes throughout China. The satellite retrievals used in this study include passive microwave observations from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and its successor AMSR2, active microwave observations from the Advanced Scatterometer (ASCAT), and the blended multi-sensor soil moisture product from the European Space Agency (i.e., ESA CCI product). We first conducted validations of the three soil moisture retrievals against in-situ observations (collected from the nationwide agro-meteorological network) in irrigated areas in China. It is found that compared to the conventional Spearman’s rank correlation and Pearson correlation coefficients, entropy-based mutual information is more suitable for evaluating soil moisture anomalies induced by irrigation. In general, around 60% of uncertainties in the anomaly of “ground truth„ time series can be resolved by soil moisture retrievals, with ASCAT outperforming the others. Following this, the potential utility of soil moisture retrievals in mapping irrigation patterns in China is investigated by examining the difference in probability distribution functions (detected by two-sample Kolmogorov-Smirnov test) between soil moisture retrievals and benchmarks of the numerical model ERA-Interim without considering the irrigation process. Results show that microwave remote sensing provides a promising alternative to detect the under-represented irrigation process against the reference LSM ERA-Interim. Specifically, the highest performance in detecting irrigation intensity is found when using ASCAT in Huang-Huai-Hai Plain, followed by advanced microwave scanning radiometer (AMSR) and ESA CCI. Compared to ASCAT, the irrigation detection capabilities of AMSR exhibit higher discrepancies between descending and ascending orbits, since the soil moisture retrieval algorithm of AMSR is based on surface temperature and, thus, more affected by irrigation practices. This study provides insights into detecting the irrigation extent using microwave-based soil moisture with aid of LSM simulations, which has great implications for numerical model development and agricultural managements across the country
Chemically Etched Open Tubular and Monolithic Emitters for Nanoelectrospray Ionization Mass Spectrometry
Structural Characterization of a Monoclonal Antibody–Maytansinoid Immunoconjugate
Structural characterization was performed
on an antibody–drug
conjugate (ADC), composed of an IgG1 monoclonal antibody (mAb), mertansine
drug (DM1), and a noncleavable linker. The DM1 molecules were conjugated
through nonspecific modification of the mAb at solvent-exposed lysine
residues. Due to the nature of the lysine conjugation process, the
ADC molecules are heterogeneous, containing a range of species that
differ with respect to the number of DM1 per antibody molecule. The
DM1 distribution profile of the ADC was characterized by electrospray
ionization mass spectrometry (ESI-MS) and capillary isoelectric focusing
(cIEF), which showed that 0–8 DM1s were conjugated to an antibody
molecule. By taking advantage of the high-quality MS/MS spectra and
the accurate mass detection of diagnostic DM1 fragment ions generated
from the higher-energy collisional dissociation (HCD) approach, we
were able to identify 76 conjugation sites in the ADC, which covered
approximately 83% of all the putative conjugation sites. The diagnostic
DM1 fragment ions discovered in this study can be readily used for
the characterization of other ADCs with maytansinoid derivatives as
payload. Differential scanning calorimetric (DSC) analysis of the
ADC indicated that the conjugation of DM1 destabilized the C<sub>H</sub>2 domain of the molecule, which is likely due to conjugation of DM1
on lysine residues in the C<sub>H</sub>2 domain. As a result, methionine
at position 258 of the heavy chain, which is located in the C<sub>H</sub>2 domain of the antibody, is more susceptible to oxidation
in thermally stressed ADC samples when compared to that of the naked
antibody