Insurer green finance under regulatory cap-and-trade mechanism associated with green/polluting production during a war.

The cap-and-trade mechanism affects firms' production and operation decisions and carbon emissions, making them move towards environmental sustainability. This article develops a contingent claims model to examine the impact of the regulatory cap-and-trade mechanism on the green finance strategy of an insurer during a war. Participating in the cap-and-trade scheme of the insurer that funds the borrowing firms also implicitly affects firm production and carbon emissions. The results show that increasing the green loans decreases the interest margin of the insurer but helps policyholder protection. The insurer is reluctant to provide green loans for the green borrowing firm and thus retards sustainable development. A stringent regulatory cap of the cap-and-trade mechanism raises the insurer's interest margin but hurts policyholder protection. From the perspective of the insurer's profit, regulatory cap efficiently derives insurer lending toward sustainability through borrowing-firm cleaner production. An increased war impacting the polluting borrowing firm increases the insurer's interest margin but harms policyholder protection, affecting insurance stability adversely. This research enriches related literature and knowledge concerning insurer green finance practices indirectly associated with cleaner production. The research also highlights the significance of the regulatory cap-and-trade mechanism that reflects cleaner production in affecting insurer performance during a war.

Leucine-rich repeat containing 8A contributes to the expansion of brain ventricles in zebrafish embryos.

The sodium osmotic gradient is necessary for the initiation of brain ventricle inflation, but a previous study predicted that organic and inorganic osmolytes play equivalently important roles in osmotic homeostasis in astrocytes. To test whether organic osmoregulation also plays a role in brain ventricle inflation, the core component for volume-regulated anion and organic osmolyte channel, lrrc8a, was investigated in the zebrafish model. RT-PCR and whole-mount in situ hybridization indicated that both genes were ubiquitously expressed through to 12 hpf, and around the ventricular layer of neural tubes and the cardiogenic region at 24 hpf. Knocking down either one lrrc8a paralog with morpholino oligos resulted in abnormalities in circulation at 32 hpf. Morpholino oligos or CRISPR interference against either paralog led to smaller brain ventricles at 24 hpf. Either lrrc8aa or lrrc8ab mRNA rescued the phenotypic penetrance in both lrrc8aa and lrrc8ab morphants. Supplementation of taurine in the E3 medium and overexpression csad mRNA also rescued lrrc8aa and lrrc8ab morphants. Our results indicate that the two zebrafish lrrc8a paralogs are maternal message genes and are ubiquitously expressed in early embryos. The two genes play redundant roles in the expansion of brain ventricles and the circulatory system and taurine contributes to brain ventricle expansion via the volume-regulated anion and organic osmolyte channels.

Rapid determination of fumonisins B1 and B2 in corn by liquid chromatography-tandem mass spectrometry with ultrasonic extraction.

A simple, sensitive, and reliable analytical method is developed for the rapid determination of fumonisin B(1) and fumonisin B(2) in corn by high-performance liquid chromatography-positive electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS). Fumonisin B(1) and fumonisin B(2) are extracted from corn with methanol-water (3:1, v/v) by means of ultrasonic extraction, and directly injected into an LC-MS-MS system after centrifugation. Fumonisin B(1) and fumonisin B(2) are separated on a Zorbax Eclipse XDB-C(18) column with a solution of methanol-water-formic acid as the mobile phase. The method is validated with respect to linearity, accuracy, precision, specificity, and stability. Moreover, the method was applied to real samples and demonstrated to be suitable for the determination of fumonisin B(1) and fumonisin B(2) in corn. The total time required for the analysis of one sample was ~30 min.

A strategy to improve serum-tolerant transfection activity of polycation vectors by surface hydroxylation.

The aim of this contribution is to develop a universal method to promote the serum-tolerant capability of polycation-based gene delivery system. A "hydroxylation camouflage" strategy was put forward by coating the polycation vectors with hydroxyl-enriched "skin". Branched polyethyleneimine (PEI) was herein used as the polycation model and modified via the catalyst-free aminolysis reaction with 5-ethyl-5-(hydroxymethyl)-1,3-dioxan-2-oxo (EHDO). PEI-g-EHDO, PEI and alkylated PEI derivative termed as PEI-g-DPA were comparatively explored with respect to the transfection efficiency in the serum-free and serum-conditioned medium. The resultant data indicate that the serum-tolerant capability largely depended on the surface composition and substitution degree. In addition to the reduced surface charge, the introduced function caused by hydroxyl coating is believed to play a crucial role for the improved properties of PEI-g-EHDOs. The EHDO modification can effectively inhibit the adsorption of BSA proteins onto polyplexes surface. And the polyplexes stability was remarkably enhanced in the presence of DNase and heparin after EHDO modification. Note that the transfection activity of PEI-g-EHDO(34.5%) in the serum-conditioned medium was even higher than that without serum addition. In contrast, serum addition led to appreciable reduction in the transfection efficiency mediated by PEI and PEI-g-DPAs. Specifically, as far as the transfection activity in the presence of serum is concerned, PEI-g-EHDO could be up to 30-fold higher than unmodified PEI25k. PEI-g-EHDO(34.5%) displayed little to no hemolytic effect and high cell-biocompatibility with nearly no cytotoxicity detected in 293T cells and HeLa cells. Taking into account the high biocompatibility and serum-tolerant transfection activity, PEI-g-EHDO(34.5%) holds great potential for the use as efficient gene vector. More importantly, it is expected that such "hydroxylation camouflage" strategy may be universally applicable for a majority of existing polycation vectors.

Poly(ß-amino amine) cross-linked PEIs as highly efficient gene vectors.

To increase the release of DNA into the cytoplasm and further improve transgene expression of nucleic acid novel polymeric gene carriers were prepared which would be biodegradable under the reducing conditions in the cytoplasm. Disulfide-containing poly(ß-amino amine)s were first synthesized and then used to cross-link low molecular weight polyethyleneimine (1800 Da) through Michael addition to obtain SS-PBAA-PEIs as the final gene carriers. The physicochemical characteristics of SS-PBAA-PEI/DNA complexes were characterized. In vitro transfection mediated by the SS-PBAA-PEIs under serum conditions was carried out. Cell uptake of the gene delivery systems was observed by confocal laser scanning microscopy. The results of the physicochemical characterisation demonstrated that the SS-PBAA-PEIs could efficiently condense DNA. In vitro transfection under serum conditions showed that SS-PBAA-PEIs had comparable or even higher transfection efficiencies than 25 kDa PEI. And SS-PBAA-PEIs showed much lower cytotoxicity compared with 25 kDa PEI. In summary, the SS-PBAA-PEIs possess great potential as non-viral gene vectors and exhibit high transfection efficiency under serum conditions.

Fabrication of lactobionic-loaded chitosan microcapsules as potential drug carriers targeting the liver.

This paper demonstrates a general approach for fabrication of lactobionic chitosan microcapsules using layer-by-layer assembly via click chemistry. Chitosan was selectively modified with either azide (CHI-Az) or alkyne (CHI-Alk) groups. The growth of the CHI-Az/CHI-Alk click multilayer was studied experimentally by multilayer assembly on planar supports. Linear buildup of the film was observed. The chitosan click capsules were also analyzed with confocal laser scanning microscopy and transmission electron microscopy. Capsules were found to have regular spherical shapes. In addition, (CHI-Az/CHI-Alk)-coated particles were modified with fluorescein isothiocyanate to ensure that the particles can be easily post-functionalized. Finally, lactobionic acid was conjugated onto the (CHI-Az/CHI-Alk)-coated particles and the lactobionic particles exhibited hepatoma cell (HepG2) targeting behavior.

Simultaneous determination of clenbuterol, salbutamol and ractopamine in milk by reversed-phase liquid chromatography tandem mass spectrometry with isotope dilution.

A simple, sensitive and reliable analytical method was developed for the simultaneous determination of clenbuterol (CLB), salbutamol (SAL) and ractopamine (RAC) in milk by ultra high performance liquid chromatography-positive electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) with isotope dilution. Samples were directly purified through HLB cartridge. Then the eluate was dried under nitrogen and residues were redissolved in mobile phase. Samples were analyzed by LC-MS/MS on an Acquity UPLC(®) BEH C(18) column with gradient elution. The samples were quantified using clenbuterol-D(9), salbutamol-D(3) and ractopamine-D(6) as internal standards. The proposed method was validated according to the European Commission Decision 2002/657/EC determining specificity, decision limit (CCα), detection capability (CCß), recovery, precision, linearity, robustness and stability. CCα values were 0.054, 0.006 and 0.008µg/kg for CLB, SAL and RAC, respectively. CCß values were 0.058, 0.007 and 0.009µg/kg for CLB, SAL and RAC, respectively. The mean recoveries, repeatability (expressed as coefficient of variation, CV(r)), and reproducibility (CV(R)) varied from 95.8 to 106.2%, from 3.60 to 6.44% (CVr), and from 4.77 to 7.53% (CV(R)), respectively. The method is demonstrated to be suitable for the determination of clenbuterol, salbutamol and ractopamine in milk. The total time required for the analysis of one sample, including sample preparation, was about 45min.

PEGylated PEI-based biodegradable polymers as non-viral gene vectors.

Novel functional biodegradable gene vectors, poly(L-succinimide)-g-polyethylenimines-g-poly(ethylene glycol) (PSI-g-PEI-g-PEGs) were synthesized by conjugating methoxy poly(ethylene glycol) (mPEG, M(w)=750 Da) to PEI segments (M(w)=800 Da) of PSI-g-PEI. The physicochemical properties of PSI-g-PEI-g-PEGs, including buffering capability, pDNA binding ability, cytotoxicity, zeta potential and the particle size of polymer/pDNA complexes, were explored. The influence of PEGylation was discussed based on a comparative study of PSI-g-PEI-g-PEGs, PSI-g-PEI and PEI25k (M(w)=25 kDa). SEM images revealed that PSI-g-PEI-g-PEG/pDNA particles have a regular shape with the diameter ranging from 70 to 170 nm. PEGylation could suppress the aggregation occurrence between complexes, resulting in a reduction of the polymer/pDNA complex size. PSI-g-PEI-g-PEGs exhibited remarkably lower cytotoxicity compared to PSI-g-PEI and PEI25k. In 293T and HeLa cells, the obtained PSI-g-PEI-g-PEGs showed very high transfection efficiency compared to PEI25k. Fluorescent confocal microscopy demonstrated that PSI-g-PEI-g-PEGs could effectively transport pGL-3 plasmids into the nuclei of HeLa cells. Taking into account the continued high transfection efficacy and decreased toxicity after PEG modification, PSI-g-PEI-g-PEGs show great potential as the non-viral vectors for gene transfection.

Self-Assembled Micelles Based on PEG-Polypeptide Hybrid Copolymers for Drug Delivery.

A series of amphiphilic poly(L-leucine)-block-poly(ethylene glycol)-block-poly(L-leucine) (PLL-PEG-PLL) hybrid triblock copolymers have been synthesized. All the blocks in this system have good biocompatibility and low toxicity. The PLL-PEG-PLL copolymers could self-assemble into micelles with PLL blocks as the hydrophobic core and PEG blocks as the hydrophilic shell, which were characterized by FT-IR, (1) H NMR, and transmission electron microscopy analysis. The critical micellar concentration of the copolymer was 95.0 mg · L(-1) . The circular dichroism spectrum shows that the PLL segments adopt a unique α-helical conformation, which is found to play an important role in controlling the drug release rate. The drug release could be effectively sustained by encapsulation in the micelles. The copolymers may have potential applications in drug delivery.

Peptide-functionalized thermo-sensitive hydrogels for sustained drug delivery.

In this study, a KRGDKK (Lys-Arg-Gly-Asp-Lys-Lys) peptide with a RGD sequence is utilized as a functional group to synthesize a novel thermo-sensitive hydrogel. The KRGDKK peptide prepared by a solid phase synthesis approach is coupled to the ends of a poly[(epsilon-caprolactone)-co-lactide]-poly(ethylene glycol)-poly[(epsilon-caprolactone)-co-lactide] (PCLA-PEG-PCLA) triblock copolymer to obtain peptide-PCLA-PEG-PCLA-peptide. The self-assembly behavior of both PCLA-PEG-PCLA and peptide-PCLA-PEG-PCLA-peptide copolymers in aqueous solution is investigated, and hydrogels prepared from PCLA-PEG-PCLA and peptide-PCLA-PEG-PCLA-peptide are also prepared. An in vitro cell viability study demonstrated that the peptide-PCLA-PEG-PCLA-peptide hydrogels do not exhibit an apparent cytotoxicity, which suggests that the hydrogels have promising potential as injectable drug-delivery systems. Furthermore, compared with the PCLA-PEG-PCLA hydrogels, the peptide-PCLA-PEG-PCLA-peptide hydrogels display improved mechanical properties because of hydrogen bonding between the amino groups of KRGDKK. An in vitro drug release study showed that the peptide-PCLA-PEG-PCLA-peptide hydrogels exhibit outstanding controlled release properties and the release of the drug could be sustained for more than a month without initial burst.

Convenient preparation of biodegradable PEI-containing polymers as non-viral vectors for gene transfection.

Poly(L-succinimide)-graft-polyethylenimines (PSPs) were prepared as non-viral vectors for gene transfection. Branched polyethylenimine (Mw= 800, PEI800) was grafted to poly(L-succinimide) (PSI) in a one-step reaction with no catalyst. Gel retardation assay showed that the mobility of PSP/pDNA complexes was completely retarded at the low N/P ratio of 0.42. In vitro transfection experiments showed that, at N/P ratio of 0.84, PSPs can reach the highest transfection level with ten-fold enhancement in 293T cells and five-fold enhancement in HeLa cells as compared with PEI25k (Mw= 25,000). Fluorescent confocal microscopy showed that pGL-3 plasmids condensed by PSPs could be effectively transported into the nuclei of HeLa cells. Significantly reduced cytotoxicity of polymers was observed towards 293T and HeLa cells, with the 50% inhibition concentration of PSPs being almost four times higher than that of PEI25k.

Facile fabrication of diblock methoxy poly(ethylene glycol)-poly(tetramethylene carbonate) and its self-assembled micelles as drug carriers.

AB type diblock methoxy poly(ethylene glycol)-b-poly(tetramethylene carbonate) (mPEG-PTeMC) copolymers were designed for the first time and used as carriers for the sustained release of the hydrophobic drug ibuprofen. In this paper, we developed a facile ring-opening polymerization (ROP) method to prepare mPEG-PTeMC copolymers under the catalysis of Novozym-435 lipase. Attractively, the polymerization has been successfully performed at 30 degrees C, close to room temperature. The data show that the copolymer compositions agree well with the feed ratio of TeMC to mPEG, indicating the controllable feature of the polymerization. The copolymer structures were characterized by (1)H NMR, IR, SEC, and DSC measurements. mPEG-PTeMC exhibits no apparent in vitro cytotoxicity toward human embryonic kidney transformed 293T cells. Those amphiphilic copolymers can readily self-assemble into nanosized micelles (about 150 nm) in aqueous solution. Their critical micelle concentrations are in the range of (1.6-9.3) x 10(-7) mol/L, determined by fluorescence spectroscopy. The micelles present high stability in PBS solution, with no obvious change in micelle diameters over 5 days. Ibuprofen can be loaded effectively in mPEG-PTeMC micelles, and its sustained release behavior is observed. Transmission electron microscopy shows that the well-dispersed spherical micelles are around 25 nm in diameter, while the diameter is 30 nm after loading ibuprofen. The release rate increases when the chain length of the PTeMC block decreases. These properties show that the micelles self-assembled from mPEG-PTeMC copolymers would have great potential as carriers for the effective encapsulation as well as sustained release of hydrophobic drugs.

Mechanistic aspects of CoII(HAPP)(TFA)2 in DNA bulge-specific recognition.

A novel octahedral complex CoII(HAPP)(TFA)2 [hexaazaphenantholine-cyclophane (HAPP), trifluoroacetate (TFA)] is a DNA bulge-specific probe with single-strand DNA cleavage activity in the presence of H2O2. This complex exhibits low affinity towards double-stranded DNA and low reactivity toward single-stranded DNA. Metal-HAPP complexes with different coordination number and ring size were synthesized and their selectivity and reactivity for DNA bulges were compared. The DNA sequence at the bulge site influences the intensity of cleavage at the bulge and the flanking sites after piperidine treatment. Cleavage specificity of CoII(HAPP)(TFA)2 was characterized extensively using scavenger reagents to quench the cleavage reaction and high-resolution polyacrylamide gel electrophoresis. In addition, 3'-phosphoglycolate cleavage products were trapped and analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. These data were used to deduce that the DNA cleavage pathway for CoIIHAPP2+ in the presence of H2O2 involves 4'-H abstraction of the deoxyribose moiety.