Probing hydrogen bond energies by mass spectrometry.

Mass spectrometry with desorption electrospray ionization (DESI) is demonstrated to be useful for probing the strength of hydrogen bonding, exemplified by various complexes of benzothiazoles and carboxylic acids in the solid state. Efficiencies for fragmentation of the complexes, quantified by collision-induced dissociation (CID) technology, correspond well with energies of the hydrogen bonds of O-H···N and N-H···O bridging each pair of benzothiazole and carboxylic acid. Linear correlations (with correlation factors of 0.8953 and 0.9928) have been established for the calibration curves of normalized collision energy at 100% fragmentation rate vs the length between donor and acceptor (in the hydrogen bond of O-H···N) as well as the slope of the fragmentation efficiency curve vs the average length difference between O-H···N and N-H···O in the complex. The mechanism responsible for determination of the hydrogen bonds is proposed on the basis of the experiments starting from the mixtures of the complexes as well as labeling with deuterium. As a complement of previously available methods (e.g., X-ray diffraction analysis), expectably, the proposed mass spectrometric method seems to be versatile for probing hydrogen bond energies.

Various Morphology of WO3 Modified Activated Carbon Supported Pd Catalysts with Enhanced Formic Acid Electrooxidation.

Activated carbon support Pd nanoparticles (NPs) modified by various WO3-shaped catalysts were prepared and applied as an efficient anode catalyst for direct formic acid fuel cells. Three forms of WO3 (nanosheets, nanoparticles, nanobars) modified activated carbon hybrids were first prepared via different syntheses, and then used as supports to synthesize three types of Pd-WO3/C catalysts by a NaBH4 reduction method. The morphology, structure, and electrochemical performances of the as-prepared Pd-WO3/C catalysts were characterized and analyzed. We can see that the noble metal particles loaded with activated carbon modified by WO3 exhibit small particle size and uniform dispersion from the transmission electron microscope image. The synthesized composite catalysts was used for the formic acid electrooxidation and showed excellent catalytic performance. The oxidation peak current density of the Pd/WO3-Nanosheets/C (40.04 mA·cm-2 was the highest, approximately 1.2 times that of Pd/C (33.00 mA·cm-2. Additionally, the long-term stability (i-t) test results show that the Pd/WO3-Nanosheets/C catalyst exhibits superior stability during formic acid electrooxidation. The reason for the increase in performance can be attributed to the following: the large specific surface area of WO3 decreases the adsorption strength of intermediates such as COad on Pd and prevents the accumulation of poisonous intermediates, thereby promoting the oxidation reaction of formic acid in the direct pathway; the catalyst-support interaction between precious metal Pd and WO3, substantially improving the catalytic performance of Pd-WO3/C catalysts.

Efficacy of poly-unsaturated fatty acid therapy on patients with nonalcoholic steatohepatitis.

AIM: To examine whether poly-unsaturated fatty acid (PUFA) therapy is beneficial for improving nonalcoholic steatohepatitis (NASH). METHODS: In total, 78 patients pathologically diagnosed with NASH were enrolled and were randomly assigned into the control group and the PUFA therapy group (added 50 mL PUFA with 1:1 ratio of EHA and DHA into daily diet). At the initial analysis and after 6 mo of PUFA therapy, parameters of interest including liver enzymes, lipid profiles, markers of inflammation and oxidation, and histological changes were evaluated and compared between these two groups. RESULTS: At the initial analysis, in patients with NASH, serum levels of alanine aminotransferase (ALT) and aspartase aminotransferase (AST) were slightly elevated. Triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol levels, markers of systemic inflammation [C-reactive protein (CRP)] and oxidation [malondialdehyde (MDA)], as well as fibrosis parameters of type IV collagen and pro-collagen type III pro-peptide were also increased beyond the normal range. Six months later, ALT and AST levels were significantly reduced in the PUFA group compared with the control group. In addition, serum levels of TG and TC, CRP and MDA, and type IV collagen and pro-collagen type III pro-peptide were also simultaneously and significantly reduced. Of note, histological evaluation showed that steatosis grade, necro-inflammatory grade, fibrosis stage, and ballooning score were all profoundly improved in comparison to the control group, strongly suggesting that increased PUFA consumption was a potential way to offset NASH progression. CONCLUSION: Increased PUFA consumption is a potential promising approach for NASH prevention and reversal.

Drug-loaded nano-microcapsules delivery system mediated by ultrasound-targeted microbubble destruction: A promising therapy method.

The nano-microcapsules drug delivery system is currently a promising method for the treatment of many types of diseases, particularly tumors. However, the drug delivery efficiency does not reach a satisfactory level to meet treatment demands. Therefore, the effectiveness of delivery needs to be improved. Based on the alterations in the structure and modification of nano-microcapsules, ultrasound-targeted microbubble destruction (UTMD), a safe physical targeted method, may increase tissue penetration and cell membrane permeability, aiding the drug-loaded nano-microcapsules ingress the interior of targeted tissues and cells. The effectiveness and exact mechanism of action of the drug-loaded nano-microcapsules delivery system mediated by UTMD have yet to be fully elucidated. In this study, the latest advancement in UTMD-mediated drug loaded nano-microcapsules system technology was reviewed and the hindrances of UTMD-mediated drug delivery were assessed, in combination with a prospective study. The findings suggested that the drug delivery efficiency of nano-microcapsules mediated by UTMD was distinctly improved. Thus, the UTMD-mediated drug-loaded nano-microcapsules delivery system may significantly improve the efficiency of drug delivery, which may be a promising new therapeutic method.

Targeted delivery of biodegradable nanoparticles with ultrasound-targeted microbubble destruction-mediated hVEGF-siRNA transfection in human PC-3 cells in vitro.

A potentially viable approach for treating late-stage prostate cancer is gene therapy. Successful gene therapy requires safe and efficient delivery systems. In this study, we report the efficient delivery of small interfering RNA (siRNA) via the use of biodegradable nanoparticles (NPs) made from monomethoxypoly(ethylene glycol)-poly(lactic-co-glycolic acid)-poly-l-lysine (mPEG-PLGA-PLL) triblock copolymers. On the basis of previous findings, cyclic Arg-Gly-Asp (cRGD) peptides were conjugated to NPs to recognize the target site, integrin αvß3, expressed in high levels in PC-3 prostate cancer cells. The suppression of angiogenesis by the downregulation of vascular endothelial growth factor (VEGF) expression has been widely used to inhibit the growth of malignant tumors. In our study, human VEGF (hVEGF)-siRNA was encapsulated in NPs to inhibit VEGF expression in PC-3 cells. Concurrently, sonoporation induced by ultrasound-targeted microbubble destruction (UTMD) was utilized for the delivery of siRNA-loaded NPs. Our results showed low cytotoxicity and high gene transfection efficiency, demonstrating that the targeted delivery of biodegradable NPs with UTMD may be potentially applied as new vector system for gene delivery.

Enhancing HSP70-ShRNA transfection in 22RV1 prostate cancer cells by combination of sonoporation, liposomes and HTERT/CMV chimeric promoter.

Gene therapy is a potentially viable approach for treating hormone-refractory prostate cancer (HRPC), it requires efficient delivery systems and a target gene. Inducing carcinoma cell apoptosis by inhibition of heat shock protein 70 (HSP70) overexpression has been emerging as an attractive strategy for cancer therapy. In our study, the high tumor-specificity of human telomerase reverse transcriptase (HTERT) expression prompted the use of an HTERT/cytomegalovirus (CMV) chimeric promoter to drive HSP70-ShRNA expression to induce HRPC 22RV1 cell apoptosis. At the same time, sonoporation induced by ultrasound-targeted microbubble destruction (UTMD) was utilized for delivery of plasmid loaded with HTERT/CMV promoter. Our results indicated the combination of sonoporation, low-dose liposomes and HTERT/CMV chimeric promoter as a delivery system has the potential to promote efficient gene transfer with lower cytotoxicity.

Three novel organosilver(I) coordination networks constructed from diallylmelamine and polycarboxylates incorporating silver-vinyl bonding.

Diallylmelamine combines with Ag(2)O and auxiliary polycarboxylates to give three stable crystalline network structures, namely, [Ag(2)(dama)(2)(nipt)·H(2)O·C(2)H(5)OH](n) (1), [Ag(2)(dama)(glu)](n) (2), and [Ag(4)(dama)(2)(pma)·2H(2)O](n) (3), (dama = diallylmelamine, H(2)nipt = 5-nitroisophthalic acid, H(2)glu = glutaric acid, H(4)pma = pyromellitic acid), which have been successfully synthesized and characterized by elemental analysis, FT-IR Spectra, powder X-ray diffraction and thermogravimetric analyses, and single-crystal X-ray diffraction. Complex 1 is a 1D double-chain extended by µ(2)-N,N'-(η(2)-vinyl)-dama and µ(3)-nipt along the b axis. Notably, dama ligands in 1 display two coordination modes (bidentate µ(2)-N,N'-(η(2)-vinyl) and monodentate µ(1)-N) and two different conformations (cis(anti-gauche) and trans(anti-anti)). In 2, a pair of centrosymmetric glu ligands clamp two Ag(I) ions to form a half paddle-wheel [Ag(2)(COO)(2)] secondary building unit (SBU) which is further extended by µ(2)-N,N'-(η(2)-vinyl)-dama to form a 1D tape. Complex 3 is a 2D sheet built from µ(3)-N,N',N''-(η(2)-vinyl)-dama and µ(8)-pma. Interestingly, apparent silver-vinyl interactions with a η(2) mode were commonly observed in the solid-state structures of 1-3 (Ag-C = 2.311(4)-2.467(5) Å). The structural dissimilarity between 1 and 2 is caused by the different auxiliary polycarboxylates and different coordination modes of dama. In addition, the thermal stabilities and emissive behaviors of them were also investigated.

Detection of two fungal biocontrol agents against root-knot nematodes by RAPD markers.

The strain ZK7 of Pochonia chlamydosporia var. chlamydosporia and IPC of Paecilomyces lilacinus are highly effective in the biological control against root-knot nematodes infecting tobacco. When applied, they require a specific monitoring method to evaluate the colonization and dispersal in soil. In this work, the randomly amplified polymorphic DNA (RAPD) technique was used to differentiate between the two individual strains and 95 other isolates, including isolates of the same species and common soil fungi. This approach allowed the selection of specific fragments of 1.2 kb (Vc1200) and 2.0 kb (Vc2000) specific for ZK7, 1.4 kb (P1400) and 0.85 kb (P850) specific for IPC, using the random Primers OPL-02, OPD-05, OPD-05 and OPC-11, respectively. These fragments were cloned, sequenced, and used to design sequence-characterized amplification region (SCAR) primers specific for the two strains. In classical polymerase chain reaction (PCR), with serial dilution of ZK7 and IPC pure culture DNAs template, the detection limits of these oligonucleotide SCAR-PCR primers were found to be 10, 1000, 500, 100 pg, respectively. In the dot blotting, digoxigenin (DIG)-labeled amplicons from these four primers specifically recognized the corresponding fragments in the DNAs template of these two strains. The detection limit of these amplicons were 0.2, 0.2, 0.5, 0.5 mug, respectively.