Cross-Linked Polyamides Synthesized through a Michael Addition Reaction Coupled with Bulk Polycondensation

A simple route is described to synthesize cross-linked polyamides (cPAs) with excellent mechanical properties at mild conditions through a Michael addition reaction coupled with bulk polycondensation. A Michael addition of methyl acrylate with 1,6-hexanediamine was conducted in a bulk state at a N–H/CC molar ratio of 1:1 under normal pressure at 50 °C, and a hexanediamine-tetraester was prepared. Bulk polycondensation of the hexanediamine-tetraester with 1,6-hexanediamine and isophoronediamine was conducted at 170 °C for 1 h and then in tetrafluoroethylene mold under reduced pressure for another 8 h. A series of cPA films were prepared. The Michael addition and the polycondensation were monitored by Fourier transform infrared, ¹H NMR, and electrospray ionization mass spectrometry spectra. The cPA films were characterized with differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and a tensile test. These cPAs exhibited <i>T</i>_g ranging from 37 to 61 °C, tensile strength up to 71 MPa, and strain at break of about 11%

Table_1_Differential influences of serum vitamin C on blood pressure based on age and sex in normotensive individuals.docx

AimHypertension is among the most prevalent chronic diseases with diverse etiology, affecting over 1 billion people globally. In numerous studies, vitamin C inversely correlated with blood pressure and was suspected to have antihypertensive properties. Currently, there is conflicting evidence regarding the relationship between vitamin C and blood pressure, with most studies being conducted on hypertensive subjects. The principal objective of this project was to investigate the relationship between vitamin C and blood pressure in normotensive adult subjects.MethodsA total of 2,533 individuals aged 20 years and above were enrolled in the present study from the National Health and Nutrition Examination Survey (NHANES) 2017-2018. Outcome variables were systolic blood pressure (SBP) and diastolic blood pressure (DBP). Serum vitamin C was regarded as an independent variable. EmpowerStats software and R (version 3.4.3) were used to examine the association between vitamin C and SBP or DBP.ResultsVitamin C was reversely correlated with both SBP (β = −0.02, 95% CI: −0.03 to −0.00, p = 0.0306) and DBP (β = −0.02, 95% CI: −0.04 to −0.01, p = ConclusionVitamin C was negatively correlated with both SBP and DBP in this cross-sectional analysis. However, a U-shaped relationship and an inverted one were also observed in certain people, which implied that, though vitamin C is considered a vital antioxidant, maintaining vitamin C at appropriate levels may be beneficial according to different populations.</p

Crystallizable and Tough Aliphatic Thermoplastic Polyureas Synthesized through a Nonisocyanate Route

A simple nonisocyanate route for synthesizing crystallizable and tough aliphatic thermoplastic polyureas (TPUreas) is described. Melt transurethane polycondensation of diethylene glycol bis­(3-aminopropyl) ether with bis­(hydroxyethyl) hexanediurethane and bis­(hydroxyethyl) isophoronediurethane was conducted at 170 °C under a reduced pressure of 3 mmHg, and a series of TPUreas were prepared. The TPUreas were characterized by GPC, FT-IR, ¹H NMR, ¹³C NMR, 2D ¹³C–¹H HSQC NMR, DEPT-135 ¹³C NMR, DSC, TGA, wide-angle X-ray scattering, atomic force microscopy, and tensile tests. The TPUreas exhibited an <i>M</i>_n up to 12 000 g/mol, an <i>M</i>_w up to 17 600 g/mol, <i>T</i>_g between 2.8 and 18.1 °C, <i>T</i>_m from 140.5 to 149.8 °C, initial decomposition temperature of over 278.4 °C, and tensile strength up to 37.81 MPa with elongation at break of 691.25%. TPUreas with high <i>T</i>_m, good tensile strength, and good toughness were prepared through a nonisocyanate route

Cell Membrane and V₂C MXene-Based Electrochemical Immunosensor with Enhanced Antifouling Capability for Detection of CD44

The inactive adsorption and interference of biomolecules in electrochemical biosensors is a topic of intense interest. Directly utilizing native cell membranes to endow electrochemical surfaces with antifouling and biocompatible features is a promising strategy, rather than attempting to synthetically replicate complex biological interface properties. In this study, we present a facial and sensitive sandwich-type antifouling immunoassay through platelet membrane/Au nanoparticle/delaminated V2C nanosheet (PM/AuNPs/d-V2C)-modified electrode as the substrate of sensing interface and methylene blue/aminated metal organic framework (MB@NH2-Fe-MOF-Zn) as an electrochemical signal probe. The biosensor perfectly integrates the high conductivity of AuNPs-loaded V2C MXene with the excellent loading property of NH2-Fe-MOF-Zn to improve the electrochemical sensing performance. In addition, the excellent antifouling properties of the homogeneous cell membrane can effectively prevent the non-specific adsorption of model proteins. The obtained antifouling biosensor possesses the capability of ultrasensitive detection of CD44 and CD44-positive cancer cell in complex liquids and exhibits good analytical performance for the analysis of CD44 with a linear range from 0.5 ng/mL to 500 ng/mL. This strategy of developing cell membrane-based biosensing systems with enhanced antifouling capability can be easily expanded to the construction of other complex biosensors, and the advanced biological probes and analytical methods provide a favorable means to accurately quantify biomarkers associated with tumor progression

Pleiotropic organ phenotypes in loss-of-function <i>idd</i> mutants.

<p>(A) Schematic illustration of the <i>idd14-1</i>, <i>idd15-5</i>, and the <i>IDD16-RNAi</i> construct. A 248-bp specific <i>IDD16</i> cDNA fragment was used for construction of <i>p35S::IDD16-RNAi</i>. (B) Semi-quantitative RT-PCR analysis of <i>IDD</i> genes in WT and <i>idd</i> mutants. The transcripts of <i>IDD14</i>, <i>IDD15</i>, and <i>IDD16</i> in the <i>idd</i> triple mutant are shown as representatives. (C) 36-day-old plants of <i>idd</i> single, double, and triple mutants. Arrows indicate the infertile siliques. The arrowheads show the increased angles between the inflorescence stems and branches. The scale bar represents 2 cm. (D) Morphology of sixth leaves in 25-day-old <i>idd</i> mutants. The longitudinal curvature (LC) index and leaf index were determined from at least 10 leaves in each genotype. The data are shown as mean values ± one SD (Student's <i>t</i>-test, *P<0.05 and ***P<0.001). (E) Enlarged floral organs and infertile siliques in the <i>idd</i> triple mutant. The arrow indicates the stigma lacking pollen. The arrowheads show the unfertilized ovules.</p

Differential and overlapping expression of <i>IDD14</i>, <i>IDD15</i>, and <i>IDD16</i>.

<p>(A) Expression of <i>IDD14</i>, <i>IDD15</i>, and <i>IDD16</i> in seedlings assayed by GUS staining. The 12-day-old transgenic seedlings carrying <i>pIDD14::GUS</i>, <i>pIDD15::GUS</i>, or <i>pIDD16::GUS</i> constructs were subjected to GUS staining assays. Insets show the primary roots. The scale bar represents 1 mm. (B) GUS staining of the florescence stems of <i>pIDD14::GUS</i>, <i>pIDD15::GUS</i>, and <i>pIDD16::GUS</i> transgenic plants. Insets show the transverse sections of inflorescence stems. The scale bar represents 2 mm. (C) GUS staining of the floral organs of <i>pIDD14::GUS</i>, <i>pIDD15::GUS</i>, and <i>pIDD16::GUS</i> transgenic plants. The scale bar represents 1 mm. (D) Expression of <i>IDD14</i>, <i>IDD15</i>, and <i>IDD16</i> in inflorescence stems assayed by RNA <i>in situ</i> hybridization. A section hybridized with an <i>IDD16</i> sense probe is shown as a control. The scale bar represents 50 µm.</p

Altered auxin accumulation and transport in gain- and loss-of-function <i>idd</i> mutants.

<p>(A) Auxin accumulation assayed with the <i>DR5∶GUS</i> reporter in WT, <i>idd14-1D</i>, and <i>idd</i> triple mutant leaves. The leaves at 3, 5, and 15 days after initiation (from top to bottom panels) were subjected to GUS staining. The scale bars represent 50 µm in the top and middle panels and 5 mm in the bottom panel. (B) Expression of the <i>DR5∶GUS</i> reporter in inflorescence stems of WT, <i>idd14-1D</i>, and <i>idd</i> triple mutant plants. The scale bars represent 2 mm in the top panel and 100 µm in the bottom panel. (C) GFP fluorescence signals in the primary roots of WT, <i>idd14-1D</i>, and <i>idd</i> triple mutant carrying a <i>DR5∶GFP</i> reporter. The scale bar represents 50 µm. (D) Quantification of the GUS activity in the organs of the WT, <i>idd14-1D</i>, and <i>idd</i> triple mutant carrying a <i>DR5∶GUS</i> reporter. Data are from three biological replicates and shown as mean values ± one SD (Student's <i>t</i>-test, *P<0.05 and **P<0.01). (E) Endogenous free IAA levels in WT, <i>idd14-1D</i>, and <i>idd</i> triple mutant plants. Aerial organs of 15-day-old plants were used for measurement of free IAA levels. Data are from four biological replicates and are shown as mean values ± one SD (Student's <i>t</i>-test, *P<0.05 and **P<0.01). (F) Polar auxin transport capability of WT, <i>idd14-1D</i>, and <i>idd</i> triple mutant stems. The inflorescence stem segments of 5-week-old plants were used to determine the basipetal IAA transport efficiency and the background acropetal movement. Data are from four biological replicates and shown as mean values ± one SD (Student's <i>t</i>-test, *P<0.05 and **P<0.01).</p

Molecular characterization of <i>CUF1</i>/<i>IDD14</i>.

<p>(A) Scheme of the genomic region flanking T-DNA insertion in <i>cuf1-D</i>. Genes are shown as thick arrows and intergenic regions are shown as lines. The orientation of T-DNA left border (LB), right border (RB), and the four CaMV 35S enhancers (4×35S) are indicated. (B) Linkage analysis of the T-DNA and <i>cuf1-D</i> phenotype. The 954-bp genomic fragments in WT and <i>cuf1-D/+</i> plants were amplified with primers in the genomic region flanking the T-DNA insertion site, and the 894-bp fragments in <i>cuf1-D/+</i> and <i>cuf1-D</i> were amplified with an LB primer and a downstream genomic primer. (C) Expression analysis of the genes flanking the T-DNA in WT and <i>cuf1-D</i> plants. <i>ACTIN2</i> (<i>ACT2</i>) was used as an internal control. Note that transcripts of At1g68130 (<i>IDD14</i>) are highly elevated in <i>cuf1-D</i>. (D) Morphology of 25-days-old WT, <i>cuf1-D</i> carrying <i>p35S::anti-IDD14</i>, and <i>p35S::IDD14</i> plants. The scale bar represents 2 cm. (E) Alignment of the ID domains in IDD14, IDD15, and IDD16. ZF1-ZF4 represents the four C2H2-type zinc finger motifs. The arrowheads indicate the conserved cysteine and histidine residues. (F) Morphology of 4-week-old transgenic plants overexpressing <i>IDD15</i> or <i>IDD16</i>. The scale bar represents 1 cm.</p

Phenotype of <i>cuf1-D</i> plants.

<p>(A) Morphology of 4-week-old wild-type (WT), <i>cuf1-D/+</i>, and <i>cuf1-D</i> plants. The scale bar represents 1 cm. (B) Blade areas of WT, <i>cuf1-D/+</i>, and <i>cuf1-D</i> leaves. (C) Transverse curvature (TC) index of WT, <i>cuf1-D/+</i>, and <i>cuf1-D</i> leaves. (D) Leaf index (ratio of length to width) in WT, <i>cuf1-D/+</i>, and <i>cuf1-D</i> plants. At least 10 sixth leaves from each genotype were used for determination of the leaf area, TC index, and leaf index as described in the methods section, respectively. Data are shown as mean values ± one SD, and the letters (a to c) indicate the significance (P<0.05) among the genotypes according to one-way ANOVA test (SPSS 13.0, Chicago, IL, USA).</p

Genetic interaction of auxin biosynthesis and IDD-mediated organ morphogenesis and gravitropism.

<p>(A) Aerial organ morphology of 25-day-old <i>idd14-1D</i>, <i>yuc2 yuc6</i>, and <i>idd14-1D yuc2 yuc6</i> plants. The scale bar represents 2 cm. (B) Gravitropic responses of WT, <i>idd14-1D</i>, <i>yuc2 yuc6</i>, and <i>idd14-1D yuc2 yuc6</i> inflorescence stems. (C) 45-day-old plants of the <i>idd</i> triple mutant, <i>35S</i>-<i>YUC2</i>, and <i>idd</i> triple mutant carrying a <i>p35S::YUC2</i> construct. The scale bar represents 2 cm. (D) The silique orientation of WT, <i>idd</i> triple mutant, <i>35S</i>-<i>YUC2</i>, and <i>idd</i> triple mutant carrying a <i>p35S::YUC2</i> construct (one-way ANOVA test, P<0.05).</p