Remarkable Melting Behavior of PLA Stereocomplex in Linear PLLA/PDLA Blends

The linear PLLA/PDLA blends were prepared by solution mixing method, and the melting behavior and structure evolution of neat PLLA and PLLA/PDLA specimens were investigated in this study. Results indicated that PLA stereocomplex crystallites (sc) preferentially formed in all blends, and the crystal structure of PLA sc and homochiral crystallites (hc) did not vary as molecular weights. The melting temperature of PLA neat specimens (<i>T</i>_hm) increased monotonously with molecular weights. However, significantly different from the neat samples, the melting temperature of PLA sc (<i>T</i>_sc) increased at first, then decreased as the molecular weight of polymers increased from 4 to 100 kg/mol. When the molecular weights of PLLA and PDLA ranged from 23 to 50 kg/mol, multimelting behaviors observed at 230 °C in the blends. After annealing at a fix temperature (<i>T</i>_sc – 10 °C), the highest <i>T</i>_sc was observed at 249.9 °C in L32/D31 specimen, which was the highest report value until now. The WAXD and SAXS results attested that not crystal structure, but the variation of the thickness of lamellar crystal was the exterior reason, and the higher optical purity of PLLA and PDLA would be the inherent cause which resulted in the superior thermal properties. This investigation provides more potential for the application of PLA sc materials at higher temperature environments

Unique Fractional Crystallization of Poly(l‑lactide)/Poly(l‑2-hydroxyl-3-methylbutanoic acid) Blend

The crystallization behaviors and microstructures of poly­(l-2-hydroxyl-3-methyl­butanoic acid)/poly­(l-lactide) blends [P­(L-2H3MB)/PLLA] were investigated by OM, DSC, SAXS, in situ temperature-dependent WAXD, and in situ synchrotron WAXS. The blends exhibited a homogeneous state at 250 °C. In the cooling process, P­(L-2H3MB), with higher melting temperature, crystallized first at 166.7 °C and drove the formation of the phase separation and microstructure. And the amorphous P­(L-2H3MB) and PLLA were excluded into the interlamellar and interfibrillar regions of the former P­(L-2H3MB) crystallites. For P­(L-2H3MB)/PLLA (5/5), the amorphous P­(L-2H3MB) in the interfibrillar regions continued to form crystallites sequentially at 134.6 °C, which clearly confirmed the fractional crystallization of P­(L-2H3MB). In our knowledge, this unique fractional crystallization has not been reported yet, of the component in miscible blend, which crystallized first under little confinement. This work provided a new viewpoint and understanding of the relationship between fractional crystallization and microstructures in crystalline/crystalline blends

Medium-Entropy Co–Fe–Cr–Mo Spinel Nanoflowers as Electrocatalysts for Oxygen Evolution

Oxygen evolution reaction (OER) plays an important role in many electrocatalysis-related fields. However, the slow kinetics of the OER seriously hinders energy efficiency. Here, we synthesize flower-like Co–Fe–Cr–Mo medium-entropy spinel (MES) nanosheets on nickel foam (NF) using one-step solvothermal method for the OER. Due to high stability and compositional diversity, the CoFeCrMoOx/NF catalyst exhibits excellent electrocatalytic OER performance with an overpotential of only 196 mV at 10 mA cm–2 in 1.0 M KOH solution, much lower than CoFeCrMnOx/NF, CoFeCrCeOx/NF, CoFeCrSnOx/NF, CoFeCrAlOx/NF, and commercial IrO2 catalysts, reflecting that the formation of flower-like MES has a positive effect on the improvement of OER performance. The introduction of Mo increases active sites, promotes electron transfer, accelerates the adsorption and desorption of the OER intermediates, reduces the energy barrier, and thus improves the performance of the OER. In situ Raman spectra indicate that the surface CoOOH and FeOOH species are important active components for the OER

PCA score plots of leaves and roots.

<p>A, PCA score plot of all leaves obtained from binned ¹H NMR data scaled to intensityof TMSP; B, PCA score plot of all leaves obtained from binned ¹H NMR data scaled to total area of the corresponding spectra; C, PCA score plot of roots from control seedlings, infested seedlings and HIPVs induced seedlings at 6 h obtained from binned ¹H NMR data scaled to intensity of TMSP; D, PCA score plot of roots from control seedlings, infested seedlings and HIPVs induced seedlings at 12 h obtained from binned ¹H NMR data scaled to intensity of TMSP; E, PCA score plot of roots from control seedlings, infested seedlings and HIPVs induced seedlings at 24 h obtained from binned ¹H NMR data scaled to intensity of TMSP; leaf samples were symbolized as follows: ▴, control for 6 h; ▪, control for 12 h; ♦, control for 24 h; △, leaves infested for 6 h; □, leaves infested for 12 h; ◊, leaves infested for 24 h; ▾, leaves exposed to HIPVs for 6 h; •, leaves exposed to HIPVs for 12 h; *, leaves exposed to HIPVs for 24 h. Symbolizations of root samples were corresponded with the symbols of leaves. Percents of the total variances for the evaluated samples explained by the first two principal components were labeled following t <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095474#pone.0095474-Uno1" target="_blank">[1]</a> and t <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095474#pone.0095474-FurstenbergHagg1" target="_blank">[2]</a> respectively.</p

Typical ¹H NMR spectra of leaves.

<p>a, ¹H NMR spectra of leaves from control plants for 12 h; b, ¹H NMR spectra of leaves from seedlings infested for 12 h; c, ¹H NMR spectra of leaves from seedlings exposed to HIPVs for 12 h. 1: α-Linoleic acid analogues, 2: ethanol, 3: threonine, 4: acetic acid, 5: oxalacetic acid, 6: glycolate, 7: α-hydroxyisobutyric acid, 8: glutaric acid, 9: succinic acid, 10: citric acid, 11: acetone, 12: choline, 13: alanine, 14: valine, 15: aspartic acid, 16: asparagin, 17: serine, 18: glycine, 19: phenylalanine, 20: sucrose, 21: α-Glucose, 22: pinitol, 23: inositol, 24: hydroxybenzene derivative 1, 25: 4-hydroxyphenylacetic acid, 26: trigonelline, 27: adenine.</p

OPLS-DA score plots (left) and corresponding loading plots (right) of roots.

<p>A, B: OPLS-DA score and loading plots of roots from seedlings infested for 12 h versus control; C, D: OPLS-DA score and loading plots of roots from seedlings exposed to HIPVs for 12 h versus control; E, F: OPLS-DA score and loading plots of roots from seedlings infested for 24 h versus control; G, H: OPLS-DA score and loading plots of roots from seedlings exposed to HIPVs for 24 h versus control. Symbolization of samples in score plots were the same with <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095474#pone-0095474-g002" target="_blank">figure 2</a>. For coefficient-coded loading plots, horizontal axis corresponds to the integrated regions of 0.4–10.0 ppm in ¹H NMR spectra; vertical axis are the back transformed loading value and colors for variables (compounds) are coded by square of coefficients (r²).</p

Correlation coefficients of significantly changed metabolites induced by herbivore or HIPVs exposure.

<p>Positive value, increase; negative value, decrease; cut value for significance: 0.811.</p

¹H chemical shifts and coupling constants (J, Hz) of metabolites in <i>A. mongolicus</i> roots identified (CD₃OD-KH₂PO₄ in D₂O, pH 6.0)

a<p>Notes: signals can just be identified as hydroxybenzene derivatives;</p>b<p>Notes: signals can just be identified as Aromatic compound.</p

Diverse associations observed between pregnancy complications and RBC or plasma folates determined by an in-house developed LC-MS/MS method

As folates are essential for embryonic development and growth, it is necessary to accurately determine the levels of folates in plasma and red blood cells (RBCs) for clinical intervention. The aims of this study were to develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantitation of folates in plasma and RBCs and to examine the association between plasma and RBC folate concentrations and gestational diabetes mellitus (GDM), gestational hypertension (GH) and preeclampsia (PE). With the in-house developed LC-MS/MS, a retrospective cross-sectional study was conducted. The healthy pregnant women of first- (n = 147), second- (n = 84) and third-trimester (n = 141) or the women diagnosed with GDM (n = 84), GH (n = 58) or PE (n = 23), that were aged between 22 and 46 years old and registered at our institute, were subjected for measurement of folic acid (FA) and 5-methyltetrahydrofolate (5-MTHF), followed by appropriate statistical association analysis. The assay for simultaneous quantitation of FA and 5-MTHF in plasma and RBCs was linear, stable, with imprecision less than 15% and recoveries within ±10%. The lower limits of quantification for FA and 5-MTHF measurement in whole blood were 0.57 and 1.09 nmol/L, and in plasma were 0.5 and 1 nmol/L, respectively. In the association analysis, the patients with lower RBC folate level ( The in-house developed LC-MS/MS method for folates and metabolites in plasma or RBC showed satisfactory analytical performance for clinical application. Further, the levels of folates and metabolites were diversely associated with GDM, GH and PE development.</p