Seasonal variability of multiple leaf traits captured by leaf spectroscopy at two temperate deciduous forests

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Remote Sensing of Environment 179 (2016): 1-12, doi:10.1016/j.rse.2016.03.026.Understanding the temporal patterns of leaf traits is critical in determining the seasonality and magnitude of terrestrial carbon and water fluxes. However, robust and efficient ways to monitor the temporal dynamics of leaf traits are lacking. Here we assessed the potential of using leaf spectroscopy to predict leaf traits across their entire life cycle, forest sites, and light environments (sunlit vs. shaded) using a weekly sampled dataset across the entire growing season at two temperate deciduous forests. The dataset includes field measured leaf-level directional-hemispherical reflectance/transmittance together with seven important leaf traits [total chlorophyll (chlorophyll a and b), carotenoids, mass-based nitrogen concentration (Nmass), mass-based carbon concentration (Cmass), and leaf mass per area (LMA)]. All leaf properties, including leaf traits and spectra, varied significantly throughout the growing season, and displayed trait-specific temporal patterns. We used a Partial Least Square Regression (PLSR) analysis to estimate leaf traits from spectra, and found a significant capability of PLSR to capture the variability across time, sites, and light environment of all leaf traits investigated (R2=0.6~0.8 for temporal variability; R2=0.3~0.7 for cross-site variability; R2=0.4~0.8 for variability from light environments). We also tested alternative field sampling designs and found that for most leaf traits, biweekly leaf sampling throughout the growing season enabled accurate characterization of the leaf trait seasonal patterns. Increasing the sampling frequency improved in the estimation of Nmass, Cmass and LMA comparing with foliar pigments. Our results, based on the comprehensive analysis of spectra-trait relationships across time, sites and light environments, highlight the capacity and potential limitations to use leaf spectra to estimate leaf traits with strong seasonal variability, as an alternative to time-consuming traditional wet lab approaches.This research was supported by the Brown University–Marine Biological Laboratory graduate program in Biological and Environmental Sciences, and Marine Biological Laboratory start-up funding for JT. JT was also partially supported by the U.S. Department of Energy (U.S. DOE) Office of Biological and Environmental Research grant DE-SC0006951 and the National Science Foundation grants DBI-959333 and AGS-1005663. SPS was supported in part by the U.S. DOE contract No. DE-SC00112704 to Brookhaven National Laboratory. JW was supported by the NASA Earth and Space Science Fellowship (NESSF2014)

One-Pot Synthesis of Hydrophilic Molecularly Imprinted Nanoparticles

Molecularly imprinted nanoparticles were prepared using a simple distillation precipitation polymerization method. In this work, propranolol-imprinted nanoparticles were synthesized using different cross-linkers combined with methacrylic acid (MAA) as a functional monomer in refluxing acetonitrile. Using the new synthetic method, uniform prorpanolol-imprinted nanoparticles were obtained in less than 3 h, which is in contrast to the long reaction time (24 h) required in previous precipitation polymerization, The new synthetic method also provides a convenient means to prepare core-shell structured nanoparticles, where the core contains imprinted binding sites and the shell has more hydrophilic characteristics. Molecular recognition properties of the imprinted nanoparticles were studied through equilibrium binding experiments. For nanoparticles containing N,N'-methylenebis(acrylamide) cross-linker, the residual C=C bonds remaining in the nanoparticles were utilized to immobilize a fluorescent compound, 1-pyrenemethylamine, through nondestructive Michael addition reaction. The fluorescent modification did not deteriorate the molecular recognition property of the nanoparticles, suggesting that the Michael addition reaction took place only in nonselective sites. Using a similar Michael addition reaction, we anticipate that the residual C=C bonds in the acrylamide moiety can be utilized to introduce other reporter molecules into molecularly imprinted nanoparticles or to immobilize such nanoparticles on amine- or thiol-functionalized surfaces to develop different chemical sensors. The hydrophilic shell of the imprinted core-shell nanoparticles shall provide effective screening to prevent nonspecific adsorption of, e.g., proteins while allowing small target molecules to enter the imprinted sites in the more hydrophobic core, thereby potentially useful for extraction of small organic molecules from complex biological samples

Poly(ether sulfone) nanoparticles and controllably modified nanoparticles obtained through temperature-dependent cryogelation

Poly(ether sulfone) (PES) nanoparticles (NPs) have broad application prospects in the field of nanomedicine. However, the current techniques could not be used to create PES-based NPs because of a lack of sophisticated equipment. In this study, a temperature-dependent cryogelation process was developed to fabricate PES NPs through PES self-assembly under unusually low polymer concentrations in the absence of any nanomanufacturing equipment or synthesis steps. The morphologies of the prepared NPs varied with the concentration difference of the initial PES solutions, and the diameter of the polymer particles reached about 50 nm with a high monodispersity. Furthermore, cocryogelation was explored in a novel manner to introduce two representative reversible addition-fragmentation chain-transfer (RAFT) agents onto the PES NPs separately for the following modification. Then, surface-initiated RAFT polymerization was also conducted to enable the controllable variation of the polymer brushes outside the NPs to verify their scalability for further application. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47485

Proteomics investigation of the changes in serum proteins after high- and low-flux hemodialysis

Purpose: This study aimed to use proteomics methods to investigate the changes in serum protein levels after high- and low-flux hemodialysis (HD). Methods: Before and after HD, serum samples were obtained from two selected patients who were treated with a Polyflux 140 H high-flux dialyzer and a Polyflux 14 L low-flux dialyzer during two continuous therapy sessions. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to identify the proteins. Results: A total of 212 and 203 serum proteins were identified after high-flux and low-flux HD, respectively. After high-flux HD, 21 proteins increased, and 132 proteins decreased. After low-flux HD, 87 proteins increased, and 45 proteins decreased. High-flux HD led to a significantly greater reduction in protein levels than low-flux HD (0.73 ± 0.13 vs. 0.84 ± 0.18, p = .00). Among the increased and decreased proteins, the isoelectric point (pI) values mainly ranged from 5 to 7, and the molecular weights (Mws) were mostly smaller than 30 kDa. The serum proteins showed no difference in pI or Mw for high- and low-flux HD. Gene ontology (GO) analysis showed that the detected proteins were related to immune system processes and complement activation. Conclusions: Serum protein levels differentially changed after high- and low-flux HD. Long-term effects should be observed in future studies

Surface-Imprinted Nanoparticles Prepared with a His-Tag-Anchored Epitope as the Template

The specific recognition of biomolecules by artificial antibodies has inspired fascination among chemists and biologists. Herein, we propose a new method to prepare epitope-oriented surface-imprinted nanoparticles with high template utilization efficiency. Using a His-tag as the anchor to facilitate the epitope immobilization/removal and the self-polymerization of dopamine to control the imprinted shell thickness, the prepared epitope-imprinted nanoparticles show specific recognition of the target protein. Moreover, with improved hydrophilicity of the His-tag-anchored epitope, this method opens up a universal route for imprinting epitopes with various polarities

arapidproteinsamplepreparationmethodbasedonorganicaqueousmicrowaveirradiationtechnique

Fast and efficient sample preparation methods are a prerequisite for protein identification in bottom-up proteomics. Here, an innovative microwave irradiation sample preparation method was developed based on an optimized organic-aqueous solvent system for protein identification. Specifically, protein solutions containing high-concentration acetonitrile were subjected to 5 min microwave irradiation. After cooling down, trypsin was added and the digestion was performed with 30 s microwave irradiation, and the resulting peptides were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A shortened processing time of only 5.5 min is needed with this method (more than 12 h is necessary in the traditional overnight protein sample preparation). Moreover, due to the absence of urea and other chaotropic reagents, the digests can be readily identified by MALDI-TOF MS. When an assessment of this method was performed by digesting a model protein BSA, 69% ± 3% sequence coverage corresponding to 47 ± 3 peptides was obtained, which shows better protein identification than that from the standard overnight protein sample preparation method (51% ± 2% sequence coverage and 23 ± 1 peptides). Another model protein α-casein was used for the analysis of protein phosphorylation with the newly developed method that yielded 4 phosphopeptides with 8 phosphorylation sites, whereas 3 phosphopeptides with 2 phosphorylation sites were obtained from the traditional overnight approach. Moreover, the organic-aqueous microwave irradiation method provides effective digestion for proteins down to fmol

arapidproteinsamplepreparationmethodbasedonorganicaqueousmicrowaveirradiationtechnique

Fast and efficient sample preparation methods are a prerequisite for protein identification in bottom-up proteomics. Here, an innovative microwave irradiation sample preparation method was developed based on an optimized organic-aqueous solvent system for protein identification. Specifically, protein solutions containing high-concentration acetonitrile were subjected to 5 min microwave irradiation. After cooling down, trypsin was added and the digestion was performed with 30 s microwave irradiation, and the resulting peptides were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A shortened processing time of only 5.5 min is needed with this method (more than 12 h is necessary in the traditional overnight protein sample preparation). Moreover, due to the absence of urea and other chaotropic reagents, the digests can be readily identified by MALDI-TOF MS. When an assessment of this method was performed by digesting a model protein BSA, 69% ± 3% sequence coverage corresponding to 47 ± 3 peptides was obtained, which shows better protein identification than that from the standard overnight protein sample preparation method (51% ± 2% sequence coverage and 23 ± 1 peptides). Another model protein α-casein was used for the analysis of protein phosphorylation with the newly developed method that yielded 4 phosphopeptides with 8 phosphorylation sites, whereas 3 phosphopeptides with 2 phosphorylation sites were obtained from the traditional overnight approach. Moreover, the organic-aqueous microwave irradiation method provides effective digestion for proteins down to fmol

cellimprintedpolydimethylsiloxanefortheselectivecelladhesion

Cell adhesion is the basis for some cell isolation methods, and is influenced by both of the biochemical and topographic characteristics of the substrates. herein, based on cell imprinting and click chemistry, we have developed a cell-imprinted polydimethylsiloxane (pdms) with aptamer functionalization (apt-cis). the atom force microscopic analysis results showed that the hierarchical structure matching well with the target cells is successfully introduced on the surface of the apt-cis. by using the synergistic effects of hierarchical structure and aptamer affinity, the apt-cis was successfully used for the selective cell adhesion, and 93.9% +/- 0.8% of the captured cells could then be released. thus, the apt-cis holds promise in selective cell isolation and sorting fields. (c) 2018 chinese chemical society and institute of materia medica, chinese academy of medical sciences. published by elsevier b.v. all rights reserved