Divergent effects of cholesterol on the structure and fluidity of liposome and catanionic vesicle membranes.

Lipid-like ion-pair amphiphile vesicles, or catanionic vesicles, have emerged as potential drug carriers. The effects of cholesterol on the properties of catanionic vesicles have yet been systematically studied. Here, we compared the effects of cholesterol on the structures and fluidities of dipalmitoylphosphatidylcholine liposomes and catanionic vesicles with similar main transition temperatures (Tm ). For liposomes, fluorescence anisotropy (FA) thermograms reveal typical condensing and disordering effects of cholesterol above and below Tm respectively. In contrast, FA and molecular simulation data reveal that catanionic bilayers below Tm are more fluidic due to shorter alkyl chains. This leads to only condensing effects of cholesterol for catanionic vesicles at all temperatures. Our results provide important insights into the fabrication of catanionic vesicles as novel drug carriers.

Stable Ethosome-like Catanionic Vesicles for Transdermal Hydrophilic Drug Delivery with Predictable Encapsulation Efficiency.

Lipid-like pseudo-double-chained catanionic surfactants have emerged as the attractive materials to prepare potential vesicular carriers in drug and gene delivery applications. In particular, the semi-spontaneous process has been developed to fabricate ethosome-like catanionic vesicles for the transdermal drug delivery. In this work, Arbutin (a water-soluble drug) encapsulation efficiency of ethosome-like catanionic vesicles fabricated from decyltrimethylammonium-tetradecylsulfate (DeTMA-TS, CH3(CH2)9 N(CH3)3-CH3(CH2)13SO4) and decyltrimethylammonium-dodecylsulfate (DeTMA-DS, CH3(CH2)9N(CH3)3-CH3(CH2)11SO4) with various amounts of ethanol and cholesterol in tris buffer solution was experimentally determined. A simple unilamellar vesicle (ULV) model, resulting in the theoretical encapsulation efficiency within ±10% error for most vesicle compositions, was also developed. Such agreement indirectly confirmed the formation of unilamellar vesicles by the preparation method. Stable ethosome-like catanionic vesicles by using catanionic surfactants with the aid of suitable amounts of ethanol and cholesterol, which led to polydispersity index (PDI) values of vesicle size distribution less than 0.3, were successfully prepared and their hydrophilic drug encapsulation efficiencies can be accurately predicted. Furthermore, the linear correlations of the trap volume ratio with both vesicle size and concentration of the extra added CHOL also provide important guidelines for controlling the drug loading of ethosome-like catanionic vesicles. The accomplishments reached for the novel vesicles are useful for developing their transdermal drug delivery applications.

Protective effect of S-nitrosoglutathione pretreatment on acute lung injury in septic rats.

OBJECTIVES: To investigate the protective effect of S-nitrosoglutathione (SNG) pretreatment on acute lung injury (ALI) in septic rats. MATERIALS AND METHODS: We constructed a rat model of sepsis by cecal ligation and perforation (CLP), and randomly divided into Sham, CLP, and CLP+SNG (0.25 and 0.5 mg/kg) groups. We used H&E staining and lung wet/dry ratio to assess the severity of lung injury, detected the levels of protein and cells in bronchoalveolar lavage fluid (BALF) and the levels of TNF-α, IL-1ß, TLR4 mRNA, and NF-κB p65 mRNA in the lung tissue, and assessed the levels of glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase in the lung tissue. RESULTS: A rat model of sepsis was successfully constructed by CLP, and pretreatment of SNG significantly increased the survival of septic rats (P<0.001) and decreased the lung tissue injury scores (P<0.001) and lung wet/dry ratio (P<0.01) in a dose-dependent manner. Furtherly, SNG pretreatment significantly reduced the number of total cells, total protein, neutrophils, and lympholytes (all P<0.001) in BALF, and which also decreased the levels of TNF-α, IL-1ß, TLR4 mRNA, and NF-κB p65 mRNA (all P<0.001) in the lungs of CLP-induced rats. Moreover, pretreatment of SNG significantly increased the levels of anti-oxidant enzymes GSH, SOD, GSH-Px, and catalase (all P<0.001) in the lung tissue of septic rats. CONCLUSION: SNG pretreatment has a protective effect on ALI in septic rats, and the specific mechanism may be related to anti-endotoxic, anti-inflammatory, and anti-oxidative properties.

Diagnostic value of miR-155 for acute lung injury/acute respiratory distress syndrome in patients with sepsis.

OBJECTIVE: We aimed to investigate the diagnostic value of microRNA-155 (miR-155) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) in patients with sepsis. METHODS: In this prospective study, we used Spearman correlation analysis to investigate relationships between miR-155 expression and inflammatory factors, oxygenation ratio (PaO2/FiO2), and ALI/ARDS score, and used area under the receiver operating characteristic curve (AU-ROC) to evaluate miR-155's diagnostic accuracy for ALI/ARDS in patients with sepsis. RESULTS: In total, 156 patients with sepsis were enrolled in our study, of which 41 had ALI and 32 had ARDS. miR-155 expression in plasma of patients with sepsis and ALI/ARDS was significantly higher than that of patients with sepsis but no ALI/ARDS. The miR-155 level in patients with sepsis and ALI/ARDS was positively correlated with interleukin (IL)-1ß and tumor necrosis factor (TNF)-α levels and ALI/ARDS score, but negatively correlated with PaO2/FiO2. The AU-ROC of plasma miR-155 for diagnosis of sepsis with ALI/ARDS was 0.87, and plasma miR-155, IL-1ß, and TNF-α had high sensitivity and specificity for the diagnosis of sepsis with ALI/ARDS. CONCLUSION: miR-155 is highly expressed in plasma of patients with septic ALI/ARDS; it is positively correlated with lung function and can be used for early diagnosis.

Proteomic profiling and identification of significant markers from high-grade osteosarcoma after cryotherapy and irradiation.

Biological reconstruction of allografts and recycled autografts have been widely implemented in high-grade osteogenic sarcoma. For treating tumor-bearing autografts, extracorporeal irradiation (ECIR) and liquid nitrogen (LN) freezing techniques are being used worldwide as a gold standard treatment procedure. Both the methods aim to eradicate the tumor cells from the local recurrence and restore the limb function. Therefore, it is essential and crucial to find, and compare the alterations at molecular and physiological levels of the treated and untreated OGS recycled autografts to obtain valuable clinical information for better clinical practice. Thus, we aimed to investigate the significantly expressed altered proteins from ECIR-and cryotherapy/freezing- treated OGS (n = 12) were compared to untreated OGS (n = 12) samples using LC-ESI-MS/MS analysis, and the selected proteins from this protein panel were verified using immunoblot analysis. From our comparative proteomic analysis identified a total of 131 differentially expressed proteins (DEPs) from OGS. Among these, 91 proteins were up-regulated (2.5 to 3.5-folds), and 40 proteins were down-regulated (0.2 to 0.5 folds) (p < 0.01 and 0.05). The functional enrichment analysis revealed that the identified DEPs have belonged to more than 10 different protein categories include cytoskeletal, extracellular matrix, immune, enzyme modulators, and cell signaling molecules. Among these, we have confirmed two potential candidates' expressions levels such as Fibronectin and Protein S100 A4 using western blot analysis. Our proteomic study revealed that LN-freezing and ECIR treatments are effectively eradicating tumor cells, and reducing the higher expressions of DEPs at molecular levels which may help in restoring the limb functions of OGS autografts effectively. To the best of our knowledge, this is the first proteomic study that compared proteomic profiles among freezing, ECIR treated with untreated OGS in recycled autografts. Moreover, the verified proteins could be used as prognostic or diagnostic markers that reveal valuable scientific information which may open various therapeutic avenues in clinical practice to improve patient outcomes.

Novel conductive polypyrrole/silk fibroin scaffold for neural tissue repair.

Three dimensional (3D) bioprinting, which involves depositing bioinks (mixed biomaterials) layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However, it remains challenging to prepare biomaterials with micro-nanostructures that accurately mimic the nanostructural features of natural tissues. A novel nanotechnological tool, electrospinning, permits the processing and modification of proper nanoscale biomaterials to enhance neural cell adhesion, migration, proliferation, differentiation, and subsequent nerve regeneration. The composite scaffold was prepared by combining 3D bioprinting with subsequent electrochemical deposition of polypyrrole and electrospinning of silk fibroin to form a composite polypyrrole/silk fibroin scaffold. Fourier transform infrared spectroscopy was used to analyze scaffold composition. The surface morphology of the scaffold was observed by light microscopy and scanning electron microscopy. A digital multimeter was used to measure the resistivity of prepared scaffolds. Light microscopy was applied to observe the surface morphology of scaffolds immersed in water or Dulbecco's Modified Eagle's Medium at 37°C for 30 days to assess stability. Results showed characteristic peaks of polypyrrole and silk fibroin in the synthesized conductive polypyrrole/silk fibroin scaffold, as well as the structure of the electrospun nanofiber layer on the surface. The electrical conductivity was 1 × 10-5-1 × 10-3 S/cm, while stability was 66.67%. A 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay was employed to measure scaffold cytotoxicity in vitro. Fluorescence microscopy was used to observe EdU-labeled Schwann cells to quantify cell proliferation. Immunohistochemistry was utilized to detect S100ß immunoreactivity, while scanning electron microscopy was applied to observe the morphology of adherent Schwann cells. Results demonstrated that the polypyrrole/silk fibroin scaffold was not cytotoxic and did not affect Schwann cell proliferation. Moreover, filopodia formed on the scaffold and Schwann cells were regularly arranged. Our findings verified that the composite polypyrrole/silk fibroin scaffold has good biocompatibility and may be a suitable material for neural tissue engineering.

A partition-type tubular scaffold loaded with PDGF-releasing microspheres for spinal cord repair facilitates the directional migration and growth of cells.

The best tissue-engineered spinal cord grafts not only match the structural characteristics of the spinal cord but also allow the seed cells to grow and function in situ. Platelet-derived growth factor (PDGF) has been shown to promote the migration of bone marrow stromal cells; however, cytokines need to be released at a steady rate to maintain a stable concentration in vivo. Therefore, new methods are needed to maintain an optimal concentration of cytokines over an extended period of time to effectively promote seed cell localization, proliferation and differentiation. In the present study, a partition-type tubular scaffold matching the anatomical features of the thoracic 8-10 spinal cord of the rat was fabricated using chitosan and then subsequently loaded with chitosan-encapsulated PDGF-BB microspheres (PDGF-MSs). The PDGF-MS-containing scaffold was then examined in vitro for sustained-release capacity, biocompatibility, and its effect on neural progenitor cells differentiated in vitro from multilineage-differentiating stress-enduring cells (MUSE-NPCs). We found that pre-freezing for 2 hours at -20°C significantly increased the yield of partition-type tubular scaffolds, and 30 µL of 25% glutaraldehyde ensured optimal crosslinking of PDGF-MSs. The resulting PDGF-MSs cumulatively released 52% of the PDGF-BB at 4 weeks in vitro without burst release. The PDGF-MS-containing tubular scaffold showed suitable biocompatibility towards MUSE-NPCs and could promote the directional migration and growth of these cells. These findings indicate that the combination of a partition-type tubular scaffold, PDGF-MSs and MUSE-NPCs may be a promising model for the fabrication of tissue-engineered spinal cord grafts.

Enhanced Physical Stability of Mixed Ion Pair Amphiphile/Double-chained Cationic Surfactant Vesicles in the Presence of Cholesterol.

In this study, a pseudodouble-chained ion pair amphiphile (IPA), hexadecyltrimethylammoniumdodecylsulfate (HTMA-DS), and dialkyldimethylammonium bromide (DXDAB) with different chain lengths were used as the main materials to fabricate positively charged catanionic vesicles with various mole fractions of cholesterol. The effects of cholesterol and DXDAB alkyl chain length on physical stability of the catanionic vesicles were then investigated by size, zeta potential, and Fourier transform infrared analyses. With the presence of cholesterol in the mixed HTMA-DS/DXDAB vesicles or with increasing the DXDAB content in the presence of a proper amount of cholesterol, the physical stability of the catanionic vesicles could be enhanced. The spacing effect of cholesterol would reduce the counterion binding tendency at the charged vesicle surfaces, resulting in a more pronounced charge character of the catanionic vesicles. Furthermore, cholesterol-induced disordered structure contributed to the flexibility of the vesicular bilayers. Thus the physical stability of the vesicles was improved by adding cholesterol. With increasing the hydrocarbon chain length of DXDAB, cholesterol located toward the middle of the bilayers, enhancing the effects of cholesterol on charge and molecular packing characteristics of the vesicles. This led to a more pronounced stability enhancement effect on the vesicles with a longer alkyl chain length of DXDAB. The results suggested that the presence of cholesterol in the HTMA-DS/DXDAB catanionic vesicles could enhance vesicle stability through adjusting intra-vesicle and/or inter-vesicle interactions. In addition, the stability enhancement effect was more pronounced in the systems with a long DXDAB alkyl chain. The findings will be useful for developing new formulas of catanionic vesicles as drug delivery carriers.

Effects of Ethanol and Cholesterol on Thermotropic Phase Behavior of Ion-Pair Amphiphile Bilayers.

Ion-pair amphiphiles (IPAs, also known as catanionic surfactants) are lipid-like double-chained molecules potentially used for fabricating liposome-like vesicular drug and gene carriers. Frequently ethanol and cholesterol are added to modulate the properties of their bilayer membranes. Effects of ethanol and cholesterol on the fundamental properties of IPA bilayers such as thermotropic phase behavior, however, is not known. In this work, the bilayer phase transition behavior of two IPAs (decyltrimethylammonium-tetradecyl sulfate, DeTMA-TS, and dodecyltrimethylammonium-dodecyl sulfate, DTMA-DS) in tris buffer with various amounts of ethanol was studied by using differential scanning calorimetry (DSC). Effect of cholesterol (CHOL) addition on bilayer phase transition of IPAs with 20 vol% ethanol was thereafter systematically investigated. The experimental results showed that the main phase transition temperature (Tm) was monotonously decreased with the increase of ethanol concentration up to 30 vol%. The degree of Tm depression by ethanol is essentially the same for the two IPAs regardless of different symmetry in the hydrocarbon chains. Further addition of CHOL, however, caused a slight decrease in Tm on the one hand and a significant decrease in the enthalpy of phase transition on the other hand. When the added CHOL exceeded a specific amount, the phase transition disappeared. More hasty disappearance of phase transition was found for IPA with asymmetric structure than the symmetric one. Possible mechanisms of ethanol effect based on binding in the headgroup region of the bilayers and CHOL effect based on opposite (condensing and disordering) interactions with IPA molecules in bilayers, respectively, were proposed.

Effects of Sterol-Like Additives on Phase Transition Behavior of Ion-Pair Amphiphile Bilayers.

The incorporation of additive in lipid bilayers is one of the ordinary approaches for modulating their properties. Additive effect on phase transition of ion-pair amphiphile (IPA) bilayers, however, is not known. In this work, four double-chained IPAs with different hydrocarbon chain lengths and symmetry were designed and synthesized from single-chained cationic and anionic surfactants by the precipitation method. By using differential scanning calorimetry (DSC), the thermotropic transition behavior from gel phase (Lß) through rippled phase (Pß') if any to liquid-crystalline phase (Lα) was studied for bilayers of these lipid-like IPAs in excess water. The effects of three sterol-like additives (cholesterol, α-tocopherol, and α-tocopheryl acetate) in IPA bilayers on thermal phase behavior were then systematically investigated. The experimental results revealed that with increasing concentration of additive, the phase transition temperatures were unaffected on the one hand and the enthalpies of phase transition were decreased on the other hand. When the addition of additive exceeded a specific amount, the phase transition disappeared. More hasty disappearance of phase transition was found for IPAs with lower total number of carbon atoms in the hydrocarbon chains. For IPAs with the same total number of carbon atoms in the hydrocarbon chains, the disappearance of phase transition is more hasty for the asymmetric one than for the symmetric one. Similar effects on thermal phase behavior of four IPA bilayers were exhibited by the three additives with similar chemical structures. Possible mechanism of additive effects on phase transition of IPA bilayers was then proposed in line with that of lipid bilayers.

Angiogenesis in tissue-engineered nerves evaluated objectively using MICROFIL perfusion and micro-CT scanning.

Angiogenesis is a key process in regenerative medicine generally, as well as in the specific field of nerve regeneration. However, no convenient and objective method for evaluating the angiogenesis of tissue-engineered nerves has been reported. In this study, tissue-engineered nerves were constructed in vitro using Schwann cells differentiated from rat skin-derived precursors as supporting cells and chitosan nerve conduits combined with silk fibroin fibers as scaffolds to bridge 10-mm sciatic nerve defects in rats. Four weeks after surgery, three-dimensional blood vessel reconstructions were made through MICROFIL perfusion and micro-CT scanning, and parameter analysis of the tissue-engineered nerves was performed. New blood vessels grew into the tissue-engineered nerves from three main directions: the proximal end, the distal end, and the middle. The parameter analysis of the three-dimensional blood vessel images yielded several parameters, including the number, diameter, connection, and spatial distribution of blood vessels. The new blood vessels were mainly capillaries and microvessels, with diameters ranging from 9 to 301 µm. The blood vessels with diameters from 27 to 155 µm accounted for 82.84% of the new vessels. The microvessels in the tissue-engineered nerves implanted in vivo were relatively well-identified using the MICROFIL perfusion and micro-CT scanning method, which allows the evaluation and comparison of differences and changes of angiogenesis in tissue-engineered nerves implanted in vivo.

Asialoglycoprotein receptor-magnetic dual targeting nanoparticles for delivery of RASSF1A to hepatocellular carcinoma.

We developed a nanovector with double targeting properties for efficiently delivering the tumor suppressor gene RASSF1A specifically into hepatocellular carcinoma (HCC) cells by preparing galactosylated-carboxymethyl chitosan-magnetic iron oxide nanoparticles (Gal-CMCS-Fe3O4-NPs). After conjugating galactose and CMCS to the surface of Fe3O4-NPs, we observed that Gal-CMCS-Fe3O4-NPs were round with a relatively stable zeta potential of +6.5 mV and an mean hydrodynamic size of 40.1 ± 5.3 nm. Gal-CMCS-Fe3O4-NPs had strong DNA condensing power in pH 7 solution and were largely nontoxic. In vitro experiments demonstrated that Gal-CMCS-Fe3O4-NPs were highly selective for HCC cells and liver cells. In vivo experiments showed the specific accumulation of Gal-CMCS-Fe3O4-NPs in HCC tissue, especially with the aid of an external magnetic field. Nude mice with orthotopically transplanted HCC received an intravenous injection of the Gal-CMCS-Fe3O4-NPs/pcDNA3.1(+)RASSF1A compound and intraperitoneal injection of mitomycin and had an external magnetic field applied to the tumor area. These mice had the smallest tumors, largest percentage of TUNEL-positive cells, and highest caspase-3 expression levels in tumor tissue compared to other groups of treated mice. These results suggest the potential application of Gal-CMCS-Fe3O4-NPs for RASSF1A gene delivery for the treatment of HCC.

Electrospun and woven silk fibroin/poly(lactic-co-glycolic acid) nerve guidance conduits for repairing peripheral nerve injury.

We have designed a novel nerve guidance conduit (NGC) made from silk fibroin and poly(lactic-co-glycolic acid) through electrospinning and weaving (ESP-NGCs). Several physical and biological properties of the ESP-NGCs were assessed in order to evaluate their biocompatibility. The physical properties, including thickness, tensile stiffness, infrared spectroscopy, porosity, and water absorption were determined in vitro. To assess the biological properties, Schwann cells were cultured in ESP-NGC extracts and were assessed by morphological observation, the MTT assay, and immunohistochemistry. In addition, ESP-NGCs were subcutaneously implanted in the backs of rabbits to evaluate their biocompatibility in vivo. The results showed that ESP-NGCs have high porosity, strong hydrophilicity, and strong tensile stiffness. Schwann cells cultured in the ESP-NGC extract fluids showed no significant differences compared to control cells in their morphology or viability. Histological evaluation of the ESP-NGCs implanted in vivo indicated a mild inflammatory reaction and high biocompatibility. Together, these data suggest that these novel ESP-NGCs are biocompatible, and may thus provide a reliable scaffold for peripheral nerve repair in clinical application.

Controlling the release of bFGF from silk fibroin membrane.

Since neurotrophic factor is easy to degrade and aggregate, it usually has a short half-life in vitro. To overcome this shortage, neurotrophic factor has been combined with the silk fibroin (SF) membrane to realize less degradation, optimal loading efficiency, sustained release, and good adsorption. By optimizing its binding conditions, main parameters were investigated and its optimal loading efficiency was obtained. bFGF was combined to SF membrane by layer by layer (LbL) static adsorption technique. The natural and nontoxic chondroitin sulfate (CS) was used as a crosslinking agent. Optimization was carried out in three aspects: the concentration of bFGF, the concentration of CS, and the reaction time. This experiment provides a better environment for the growth of cells and offers a new kind material of absorbing neurotrophic factor to meet increasing demand for biological materials.

[In vitro effect of total flavones of Fructus Chorspondiatis on expression of collagen type I and type III mRNA and protein of cultured rat cardiac fibroblasts].

This study aims to investigate the effect of total flavones of Fructus Chorspondiatis (TFFC) on the mRNA and protein expression of collagen type I and III of rat cardiac fibroblasts (CFs) induced by angiotensin II (Ang II), and explore its anti-myocardial fibrosis molecular mechanism. Neonatal rat CFs were prepared from Sprague-Dawley rats (1-3 d after birth). The expression of collagen type I and III mRNA and protein were measured by RT-PCR and Western blotting, respectively. The study showed that stimulation of neonatal rat CFs with 100 nmol.L-1 of Ang II for 72 h resulted in a significant increase of the expression of collagen type I and III mRNA and protein. The changes on the expression level were blocked by TFFC. The results demonstrated that TFFC can inhibit myocardial fibrosis induced by Ang II in rats, which is probably associated with the collagen type I and III mRNA and protein levels up-regulated by Ang II, and TFFC was shown to decrease the expression levels of collagen type I and III mRNA and protein.

High expressions of histone methylation- and phosphorylation-related proteins are associated with prognosis of oral squamous cell carcinoma in male population of Taiwan.

Since 2008, oral squamous cell carcinoma (OSCC) has climbed to the fourth place in cancer mortality in the male population of Taiwan. Epigenetic regulations including DNA methylation and histone modification control gene expression and play important roles during cancer progression. Since the relationship between histone modification and prognosis of OSCC is inconclusive, we collected 215 formalin-fixed and paraffin-embedded tissues from male patients having OSCC and surveyed them by tissue microarray-based immunohistochemical staining. The association between five histone modification-related genes, clinicopathological parameters, and prognosis of OSCC was examined. From tissue microarray immunohistochemistry staining results, we found that the nuclear staining intensity of ARK2 (Aurora kinase B-a serine/threonine-protein kinase of H3S10) was associated with poor clinical outcomes (≤3-year survival, p = 0.005). The cytosolic staining intensity of the ARK2 protein was associated with tumor stage (p = 0.006) and tumor size (T) of TNM staging system (p = 0.026). Cytoplasmic staining intensity of G9a (H3K9 methyltransferase) was associated with histological grade of differentiation (p = 0.026). EZH2 (H3K27 methyltransferase) and SUV39H1 (H3K9 methyltransferase) overexpressions in nuclei were, respectively, associated with lymph node metastasis (N, p = 0.016) and stage (p = 0.009). Our result suggests that overexpressions of histone modification-related proteins-ARK2, G9a, EZH2, and SUV39H1 but not SUV39H2 are associated with prognosis of OSCC in the male population of Taiwan. These proteins, especially ARK2, may serve as effective prognostic factors and can also be used as biomarkers for predicting various clinical outcomes of OSCCs in the Taiwanese population.

Highly efficient gel-state dye-sensitized solar cells prepared using poly(acrylonitrile-co-vinyl acetate) based polymer electrolytes.

Poly(acrylonitrile-co-vinyl acetate) (PAN-VA) is utilized as a gelation agent to prepare gel-state electrolytes for dye-sensitized solar cell (DSSC) applications. Based on the synergistic effect of PAN-VA and TiO(2) fillers in the electrolyte, the gel-state DSSC can achieve a conversion efficiency higher than that of a liquid counterpart. The high performance of the gel-electrolyte is attributed to the in situ gelation property of the gel-electrolyte, the contribution of the PAN-VA to the charge transfer, as well as the enhancement effect of TiO(2) fillers on the charge transfer at the Pt-electrolyte interface. The experimental results show that the efficiencies of the gel-state cells have little dependence on the conductivity of the electrolytes with various contents of PAN-VA, but are closely related to the penetration situation of the electrolyte in the TiO(2) film. For PAN-VA concentrations ≤15 wt%, the electrolyte can be easily injected at room temperature based on its in situ gelation property. For higher PAN-VA concentrations, good penetration of the high viscous electrolyte can be achieved by elevating the operation temperature. By utilizing a heteroleptic ruthenium dye (coded CYC-B11), gel-state DSSCs with an efficiency of above 10% are obtained. Acceleration tests show that the cell is stable under one-sun illumination at 60 °C.

[The application of circular stapler in extraperitoneal colostomy].

OBJECTIVE: To evaluate the clinical and application value of circular stapler in extraperitoneal colostomy. METHODS: Retrospective analysis was made to 22 cases that experienced extraperitoneal colostomy with circular stapler from Match 2008 to March 2009 in the department of colon and anal surgery of the first hospital of Jilin University. RESULTS: The length of surgery was (15 +/- 5) min when circular stapler- assisted extraperitoneal colostomy was used, and all of the colostomies were successfully completed during the first procedure. No complications occurred after surgery, such as stoma bleeding, necrosis, infection, retraction, stenosis, intestinal obstruction and hernia beside the stoma etc. Colostomy size of the uniform, beautiful shape formation. Although there were three cases requiring hemostasis due to anastomotic bleeding that occurred during the operation. About 3 months later, staples of the stoma fell off by themselves. All patients were followed up for 6 to 24 months after operation, form and function of colostomy are well. CONCLUSION: The popularization of the application of circular stapler in extraperitoneal colostomy is important and worthwhile for its obvious advantages such as simple operation, good stoma appearance and reduced complications.

Gelation of charged catanionic vesicles prepared by a semispontaneous process.

Various stable charged catanionic vesicles with mean zeta-potential values from +59 mV to -96 mV were successfully prepared from an ion-pair amphiphile (dodecyltrimethylammonium-dodecylsulfate, DTMA-DS) and different amounts of the component ionic surfactants (dodecyltrimethylammonium bromide and sodium dodecyl sulfate) by using a simple semispontaneous process with the aid of cosolvent (1-propanol) addition in water. With the ensuring positively and negatively charged catanionic vesicles, gelation of them by four water-soluble polymers with various charge and hydrophobic characteristics was systematically studied by the tube inversion and rheological characteristic analyses. Four phase maps, which show regions of phase separation, viscous solution, and gel by varying the vesicle composition and polymer content, were thereby constructed. Furthermore, the experimental results of the relaxation time and the storage modulus at 1 Hz for the viscous solutions and gel samples revealed that the interactions at play between charged catanionic vesicles and the water-soluble polymers are of electrostatic and hydrophobic origin. The phase maps and the rheological properties obtained for mixtures of charged catanionic vesicles and polymers may provide useful information for the potential application of catanionic vesicles in mucosal or transdermal delivery of drugs.

Stability enhancement effect of normal long-chain alcohols on ion pair amphiphile monolayers at the air/water interface.

Monolayer behavior of an ion pair amphiphile (IPA), hexadecyltrimethylammonium-dodecylsulfate (HTMA-DS), with normal long-chain alcohols at the air/water interface was analyzed by the Langmuir trough technique with the Brewster angle microscope (BAM) observations, and the pronounced stability enhancement of a HTMA-DS monolayer with the presence of the alcohol additives was demonstrated. Two normal long-chain alcohols with alkyl chain lengths of C16 and C18, 1-hexadecanol (HD) and 1-octadecanol (OD), were chosen as the additives. The surface pressure-area and surface potential-area isotherms of the monolayers with BAM images of monolayer morphology implied that the addition of either HD or OD with a comparatively small head group in a double-chained HTMA-DS monolayer at the interface led to better molecular packing and attractive interaction between the molecules, showing a similar condensing effect as that observed in mixed phospholipid/cholesterol systems. Moreover, the monolayer hysteresis and relaxation curves indicated that the incorporation of the alcohols into a HTMA-DS monolayer was able to lessen the monolayer hysteresis and to enhance the monolayer stability. In comparison with OD, HD seemed more effective as an additive in stabilizing a HTMA-DS monolayer, most likely due to the relatively better molecular packing of HTMA-DS and HD molecules at the interface. It is inferred that the stability of a monolayer or vesicular bilayer structure composed of IPAs can be improved by adjusting the molecular packing/interaction with a suitable long-chain alcohol as the additive.