The Optimal Condition of Poly(I: C)-Induced Knockout of Cre Recombinase for Mx1-Cre/ Cre-loxP Mice

BackgroundThe Cre-loxP system is widely applied for conditional knockout mice, commonly used to study the function of specific genes. Although some different promoters drive Cre expression, the poly(I: C)-inducible Mx1-Cre is the most commonly used to delete the target gene in experimental hematology. However, the optimal induction knockout condition for Mx1-Cre/ Cre-loxP mice using the Poly(I:C)-inducible Cre-loxP conditional system remains unclear. Here, we present two different components and three injection protocols of poly(I: C) to find the optimized condition. ResultsThe results showed that the better knockout efficiency of Cre-loxP in mice injected with pure poly(I: C) has than those injected with poly(I: C) with some components. From the perspective of lethal genes (Brg1), data showed that mice injected with a single high dose (500 µg) of pure Poly (I:C) had a lower knockout rate. For mice injected media-dose (10µg/g) poly(I: C) triple, which induced a high knockout rate, but the mortality rate was still high. Importantly, the mice injected low-dose (6µg/g) poly(I: C) triple, both the knockout rate and survival rate of mice was high. Similarly, the knockout rate of non-lethal mice injected with media-dose (10µg/g) or low-dose (6μg/g) poly(I: C) triple was very high, but injected with a single high dose (500 µg) of pure poly(I: C) had a low knockout rate. ConclusionOur studies provided the optimized condition for using poly(I: C)-inducible effective knockout and maintaining the survival rate for the Cre-loxP mice, which might be applied in other knockout mice for this system to ensure both the gene knockout and the mice survival.

A Simple Synthesis of Higher Refractive Index Polymeric Nanocomposite Containing the Pendant ZnS Nanocrystals Capping Different Amount of Mercaptoethanol

In this paper, three kinds of ZnS NPs capping different amount of mercaptoethanol (ME) were synthesized, and the effect of capping amount on ZnS NPs was studied, indicating that the capping amount of ME on ZnS surface decreases, while ZnS size increases as the decrease of added capping agent in synthesis process, and ZnS NP capping middle amount of ME (~27.7 wt%) shows a highest apparent refractive index (RI) value. ZnS NPs were composited into polymeric matrices by a simple “one-step” thermocuring method characterized by adding a small amount of functional monomer of glycidyl methacrylate (GMA) and solvent of N,N-dimethylformamide (DMF) The reaction mechanism, studied by 1H NMR spectra, indicates that the epoxy of GMA monomer can be easily opened and chemically grafted on ME-capped ZnS surface under the catalysis of DMF, and then copolymerized with other monomer. By the route, ZnS NPs can be composited into pure poly(N,N-dimethylacrylamide)-type (DMA-type), DMA-type copolymer, and DMA-free matrices to fabricate transparent films, and its RI value can be improved by either optimizing capping amount on ZnS surface or increasing ZnS content in the nanocomposites. The RI value of resulting dried nanocomposites can be improved to 1.764 by compositing 80 wt% ZnS capping middle amount of ME.

SUN-137 Clonal Status of Multigland Disease Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a common endocrine disorder that arises due to single or multiple parathyroid gland disease (MGD). The molecular mechanism(s) of parathyroid neoplasia are incompletely understood and both monoclonal (mono-X) and polyclonal (poly-X) parathyroid tumors have been described using methylation-sensitive PCR of X-linked Human Androgen Receptor (HUMARA) alleles. Our previous investigations of parathyroid tumor clonal status has shown that poly-X tumors are common and are associated with MGD in patients with non-familial PHPT (Shi et al. 2014 & 2018). This work examined the clonal status of the dominant gland and the clonal relationship of multiple tumors from the same patient has not been examined. The goal of the current study was to determine the clonal relationship of parathyroid tumors from PHPT patients with MGD. Banked parathyroid tissues from twenty-nine PHPT patients with MGD were examined in this study. Clonal status (mono-X vs poly-X) of multiple abnormal parathyroid glands from each patient was determined using a modification of the HUMARA assay used in our prior work. Briefly, methylation-sensitive PCR of HUMARA alleles was performed followed by fragment analysis using Capillary-Electrophoresis performed. Raw fragment sizing data analyzed using Peak Scanner software. Classification of samples as either mon-X or poly-X was made as described in (Shattuck et al.) Of 29 PHPT patients with MGD, 13 (45%) had pure mono-X, 5 (17%) had pure poly-X, and 11 (38%) had a mixture of mono-X and poly-X tumors. Five of 29 patients had three or more abnormal glands evaluated: 3 had mixture of poly-X and mono-X, 2 had pure mono-X tumors, and none were pure polyclonal-X. Eighteen (62%) out of 29 patients had paired upper or lower double adenomas. Of these, 9 (50%) were pure mono-X, 4 were pure poly-X, and 5 were mixed mono-X/poly-X. In 2 patients with multiple mono-X tumors, allele distribution was not the same in different abnormal glands. Our previous work has demonstrated that among patients with non-familial PHPT, poly-X parathyroid tumors are common and are associated with MGD. Our new data extend these findings to show that the clonal relationship between multiple parathyroid tumors from the same patient is complex and may reflect the emergence of single or multiple tumors from a background of parathyroid hyperplasia, or other mechanism(s). Future studies to explore the mechanisms behind these apparent clonal relationships are warranted and ongoing. Reference: (1) Shi et al., PNAS 2014, 201319742. (2) Shi et al., Surgery 2018, 9-14. (3) Shattuck. N Engl J Med 2005, 2406-12.

Electrical properties, characterization, and preparation of composite materials containing a polymethacrylate with α-naphthyl side group and nanographene fillers

2-(Naphthalene-1-yl oxy)-2-oxoethyl methacrylate (NOEMA) was synthesized from reaction of naphthalene-1-yl 2-chloroacetate and sodium methacrylate and its homopolymer was prepared by free-radical polymerization method at 60°C. The glass transition temperature of pure poly(NOEMA) was estimated as 102°C by differential scanning calorimetry technique, whereas that of poly(NOEMA) containing 10 wt% nanographene was 83°C. While pure poly(NOEMA) from thermogravimetric analysis measurements was indicating a decomposition at 290°C, poly(NOEMA) composite containing 10 wt% nanographene showed thermal decomposition temperature at 261°C. Semiconducting composites of poly(NOEMA) have been prepared by adding nanographene particles to poly(NOEMA) for preparing nanocomposites with different weight percentages (2, 3, 4, 5, and 10 wt%). The dielectric constant, ∊′, and dielectric loss factor, ∊″, of pure poly(NOEMA) were 3.66 and 0.052, respectively, whereas those of poly(NOEMA) containing 10 wt% nanographene were 186 and 210,152, respectively. Alternating current (AC) conductivity of pure poly(NOEMA) was 2.03 × 10−9 S cm−1, whereas that of poly(NOEMA) containing 10 wt% nanographene was 0.00134 S cm−1. AC conductivity mechanism of poly(NOEMA)/10 wt% nanographene composite indicated the correlated barrier hopping model. Activation energy values of poly(NOEMA)/ x wt% nanographene composites was estimated to be between 4.783 eV and 0.209 eV. The polymer composite/p-Si thin-film heterojunction diode properties have been investigated from current–voltage at room temperature. The electrical parameters of the prepared diodes such as ideality factor ( n), the barrier height (BH; Φ b), rectification ratio, and reverse saturation current ( I o) were investigated at dark and room temperature. The ideality factor ( n) value of the Al/poly(NOEMA)/ x wt% nanographene/p-Si/Al diode for dark was found to be between 5.147 and 7.504, respectively. The BH ( Φ b) value of the Al/poly(NOEMA)/ x wt% nanographene/p-Si/Al diode at dark was found to be between 0.228 and 0.64.

Tuning the Swelling Properties of Smart Multiresponsive Core-Shell Microgels by Copolymerization

The present study focuses on the development of multiresponsive core-shell microgels and the manipulation of their swelling properties by copolymerization of different acrylamides—especially N-isopropylacrylamide (NIPAM), N-isopropylmethacrylamide (NIPMAM), and NNPAM—and acrylic acid. We use atomic force microscopy for the dry-state characterization of the microgel particles and photon correlation spectroscopy to investigate the swelling behavior at neutral (pH 7) and acidic (pH 4) conditions. A transition between an interpenetrating network structure for microgels with a pure poly-N,-n-propylacrylamide (PNNPAM) shell and a distinct core-shell morphology for microgels with a pure poly-N-isopropylmethacrylamide (PNIPMAM) shell is observable. The PNIPMAM molfraction of the shell also has an important influence on the particle rigidity because of the decreasing degree of interpenetration. Furthermore, the swelling behavior of the microgels is tunable by adjustment of the pH-value between a single-step volume phase transition and a linear swelling region at temperatures corresponding to the copolymer ratios of the shell. This flexibility makes the multiresponsive copolymer microgels interesting candidates for many applications, e.g., as membrane material with tunable permeability.

Thermally stimulated depolarization current characteristic of EVA–conductive PPy composites

Thermally stimulated depolarization current in pure poly(ethylene-co-vinyl acetate) and poly(ethylene-co-vinyl acetate) composites with different amounts of polypyrrole/carbon nanoparticles (of various weight ratios, 100:0, 95:5, 90:10, 85:15, 80:20, and 70:30) have been investigated at poling temperature 363 K using different polarizing voltage. Thermograms of pure and composite samples have two or three peaks over all temperature ranges depending on the polarizing voltage. The decrease in peak height with increased polarized voltage is observed in pure poly(ethylene-co-vinyl acetate) samples loaded with 5%, 10%, 15%, and 30% polypyrrole due to the detrapping of the large amounts of charge results in electrode blocking and decrease in thermally stimulated depolarization current in those samples. The molecular parameters, such as activation energy E, charge released Q, and relaxation times τ0 and τ m for thermally stimulated depolarization current peaks have been estimated.

(Bio)degradable Polymeric Materials for Sustainable Future—Part 2: Degradation Studies of P(3HB-co-4HB)/Cork Composites in Different Environments

The degree of degradation of pure poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] and its composites with cork incubated under industrial and laboratory composting conditions was investigated. The materials were parallelly incubated in distilled water at 70 °C as a reference experiment (abiotic condition). It was demonstrated that addition of the cork into polyester strongly affects the matrix crystallinity. It influences the composite degradation independently on the degradation environment. Moreover, the addition of the cork increases the thermal stability of the obtained composites; this was related to a smaller reduction in molar mass during processing. This phenomenon also had an influence on the composite degradation process. The obtained results suggest that the addition of cork as a natural filler in various mass ratios to the composites enables products with different life expectancies to be obtained.

Using Carbon-fibre Reinforcement with a 5-axis Material Extrusion System

One of the main limitations of material extrusion (ME) components is their anisotropic mechanical behaviour, mainly due to the poor bonding between layers. 5-axis ME has the capability to orientate theprint layers in line with loading conditions, in order to limit the effect of poor inter-laminar bonding. Previous work has demonstrated how aligning deposited material in the same direction as the dominant stresses can improve a part’s mechanical performance. When fibre-reinforcement is added to theseoriented layers, the stiffness and strength of parts should increase further. This paper presents a comparison between 5-axis parts that were printed in pure poly-lactic acid (PLA) and in carbon-fibrereinforced (CFR) PLA. Sets of dome-shaped components were built using several different build strategies and tested for compressive stiffness and strength. The results were rather mixed but did show a marked improvement in compressive strength under certain conditions. Further work is required to understand one of the failure mechanisms that was seen and to overcome some of the limitations of the 5-axis machine currently being used. The work was undertaken to support the Directional Composites through Innovative Manufacturing (DiCoMI) project, funded by the European Commission.