MoO2-CoO coupled with a macroporous carbon hybrid electrocatalyst for highly efficient oxygen evolution

Cost-effective electrocatalysts for oxygen evolution reactions are attractive for energy conversion and storage processes. A high-performance oxygen evolution reaction (OER) electrocatalyst composed of 3D ordered microporous carbon and a MoO2 skeleton modified by cobalt oxide nanoparticles (MoO2-CoO-Carbon) is produced through a template method. This unique 3DOM structure finely combines the larger surface area of the 3D carbon skeleton and MoO2 as well as stablizes anchoring sites for CoO nanocrystals on the skeleton. The synergistic effect between the catalytic activity between MoO2 and CoO as well as the enhanced electron transport arising from the carbon skeleton contributed to superior electrocatalytic OER properties of MoO2-CoO-Carbon. The M200-C-Carbon hybrid with an overpotential as low as 0.24 V is among the best reported Mo-based OER catalysts. Moreover, the turnover frequency at an overpotential of 0.35 V is 6 times as high as that of commercial RuO2.

Co-Extrusion Layer Multiplication of Rheologically Mismatched Polymers: A Novel Processing Route

Co-extruded films with up to 65 layers of two rheologically mismatched polymer systems – polystyrene/poly(methylmethacrylate) (PS/PMMA) and hard/soft thermoplastic polyurethanes (TPUs) – were successfully produced using a combination of a 9-layer feedblock, low-pressure drop multiplier dies, and external lubricants. Formation of viscoelastic instabilities was studied using a custom visualization and by finite element method (FEM) simulations of a standard multiplier. The results showed that the flow inside the standard multiplier die is highly non-uniform, with severe gradients in shear and normal stresses and viscous encapsulation occurring mainly in the initial multiplication stages where there is enough material available in the low-viscosity layers to proceed with the encapsulation. To mitigate layer degradation the standard 2- or 3-layer feedblock was replaced with a 9-layer one, thereby decreasing the thickness of each layer at the end of the feedblock. Also, subsequent layering was performed using a low flow resistance die. This new multiplier die yields a more uniform flow profile and imparts a more homogeneous thermo-mechanical history on the melt which results in an improved layer stability. Simulations showed that in the standard die the second normal-stress difference (N2) responsible for elastic instabilities at the edges of the die are very high. These can be reduced by inducing slip at the wall resulting in be much improved layer uniformity and stability. This was accomplished experimentally via the use of external lubricants, and the resulting layered structure was indeed much better than was possible to achieve with the conventional multiplier dies.

Effects of Lipoxin A4 on antimicrobial actions of neutrophils in sepsis

In sepsis, hyperactivation of neutrophils can lead to tissue injury. Later, neutrophil dysregulation with reduced levels of migration, decreased apoptosis and inadequate phagocytosis may impair the host׳s ability to clear infection. Lipoxin A4 (LXA4) is a pro-resolution lipid mediator which reduces neutrophil migration and inflammatory mediator expression. As neutrophil migration and activation are important in bacterial clearance, the role of LXA4 in regulating neutrophil function for bacterial clearance is unclear. Using the cecal ligation and puncture (CLP) rat model of sepsis, LXA4 given after 1h reduced blood bacterial load at 24h. LXA4 treatment decreased neutrophil migration to the peritoneum but augmented blood neutrophil phagocytic ability and promoted apoptosis without affecting free radical production. In contrast, LXA4 increased peritoneal neutrophil phagocytic ability without affecting apoptosis or free radical production suggesting that in vivo effects of LXA4 were compartment specific. To investigate if LXA4 acted directly on neutrophils, blood and peritoneal leukocytes were taken from CLP rats 1h after surgery and incubated ex vivo with and without LXA4. LXA4 (1nM) increased phagocytosis in blood neutrophils without affecting apoptosis or free radical production. Ex vivo LXA4 had no effect on peritoneal neutrophils which suggests that LXA4 enhanced peritoneal neutrophil phagocytic ability in vivo by an indirect mechanism. The results suggest that LXA4 reduced neutrophil migration, but increased neutrophil bacteria clearing function without excessive free radical production. This phenotype was associated with reduced blood bacteria load.

Thermal degradation of hexachlorobenzene in the presence of calcium oxide at 340-400 °C

Hexachlorobenzene (HCB) in the milligram range was co-heated with calcium oxide (CaO) powder in sealed glass ampoules at 340-400 °C. The heated samples were characterized and analyzed by Raman spectroscopy, elemental analysis, gas chromatography/mass spectrometry, ion chromatography, and thermal/optical carbon analysis. The degradation products of HCB were studied at different temperatures and heated times. The amorphous carbon was firstly quantitatively evaluated and was thought to be important fate of the C element of HCB. The yield of amorphous carbon in products increased with heating time, for samples treated for 8h at 340, 380 °C and 400 °C, the value were 17.5%, 34.8% and 50.2%, respectively. After identification of the dechlorination products, the HCB degradation on CaO at 340-400 °C was supposed to through dechlorination/polymerization pathway, which is induced by electron transfer, generate chloride ions and form high-molecular weight intermediates with significant levels of both hydrogen and chlorine, and finally form amorphous carbon. Higher temperature was beneficial for the dechlorination/polymerization efficiency. The results are helpful for clarifying the reaction mechanism for thermal degradation of chlorinated aromatics in alkaline matrices.

Lipoxin A(4) promotes more complete inflammation resolution in sepsis compared to stable lipoxin A(4) analog

In sepsis, excessive inflammation may lead to organ injury or a paradoxical immunosuppressed state where the host is unable to clear preexisting infection. Resolution of inflammation is the process which restores tissue homeostasis and ensures that a chronic cycle of infection/inflammation does not occur. Lipoxin A4 (LXA4) is one of a family of lipid mediators with novel inflammation resolution activity. We compared the actions of LXA4 to the stable 15-epi-16-(para-fluorophenoxy)-lipoxin A4 methyl ester (LXA4 analog) in the cecal ligation and puncture (CLP) model of sepsis. Both LXA4 compounds (at 7 μg/kg; i.v.) reduced plasma TNFα and IL-6 concentrations compared to rats given vehicle saline. Neither treatment altered plasma IL-10 compared to CLP given saline, but LXA4 analog, increased plasma IL-10 concentrations compared to rats given LXA4. LXA4 reduced blood bacterial load but the LXA4 analog did not. LXA4 increased 8 day survival and the LXA4 analog did not have a significant effect. To examine possible mechanisms for the differences, we investigated peritoneal leukocyte gene expression of iNOS and macrophage phagocytic ability. Only LXA4 increased the percentage of phagocytic peritoneal macrophages. LXA4 reduced neutrophil gene expression of iNOS compared to CLP rats given vehicle, while the LXA4 analog did not. Our results suggest that at doses which reduced systemic inflammation, only LXA4 inhibited bacterial spread and increased survival. This difference may be due to the shorter-lived compound being able to increase macrophage phagocytosis and reduce neutrophil iNOS expression.

Association between polymorphisms in IL17F and male asthma in a Chinese population

BACKGROUND AND OBJECTIVES

Interleukin (IL) 17F is a marker of type 17 helper T cells and has a proinflammatory role in asthma.The aim of the present study was to assess the possible association between asthma and polymorphisms in the IL17F gene in a Chinese population.

METHODS

A total of 318 asthmatic patients and 352 nonasthmatic controls were recruited. Two single-nucleotide polymorphisms in IL17F (rs763780 and rs13209590) were detected using GenomeLab SNPstream. Logistic regression methods were used to analyze data.

RESULTS

A significantly lower frequency of the C allele in rs763780 was observed in the control group (P = .0148). The rs763780 TC heterozygote was associated with an increased risk of asthma, and a similar trend was observed assuming a codominant genotype effect (adjusted OR, 1.58; 95% CI, 1.06-2.36; P = .0148; adjusted OR, 1.64; 95% CI, 1.10-2.45; P = .0217). Furthermore, a novel finding of the present study was that this association was exclusive to males (adjusted OR, 1.79; 95% CI, 1.06-3.05; P = .0308) and patients with higher immunoglobulin E levels (> or = 1.85 IU/mL) (adjusted OR, 1.88; 95% CI, 1.10-3.22; P = .0213). We also found that the haplotype with minor alleles for rs763780 was associated with an increased risk of asthma (adjusted OR, 1.62; 95% CI, 1.11-2.35; P = .0115).

CONCLUSION

Our findings indicated that polymorphisms might play a role in susceptibility to asthma.

The ratios of individual chemicals in a mixture determine the degree of joint effect: the climax hypothesis

A new hypothesis, the Climax Hypothesis, is proposed to describe how the ratios of individual chemicals influence the joint effects of chemical mixtures. This hypothesis is derived from a generalized approach using "isobolograms". With this hypothesis, one can predict that for a given mixture, a curvilinear correlation exists between the joint effects and the ratios of individual chemicals and that this curve has a climax at the equitoxic ratio. This prediction is supported by the observed toxicity to Vibrio fischeri of 18 mixtures (12 binary mixtures, 4 ternary mixtures, and 2 quaternary mixtures). With this prediction, the Climax Hypothesis has some promising applications such as controlling the discharge of effluents in environmental science, maximizing detoxifying effects in medicine, and optimizing combined pesticides in agriculture.

Heterogenous and compartment-specific activation of nonlymphocytic, mononuclear cells in intraabdominal sepsis

Although sepsis is associated with increased production of cellular pro- and anti-inflammatory mediators by monocyte/macrophages, the compartmentalization and nature of such activation has not been clearly defined. The authors examined the activation of nonlymphocytic mononuclear cells in different compartments in the cecal ligation and puncture (CLP) model of septic peritonitis. Control and CLP rat mononuclear cells from the peritoneal cavity, bronchoalveolar, as well as the lung vascular compartment were isolated 24 and 48 hours post surgery and release of nitric oxide (NO), interleukin (IL)-12, and monocyte chemoattractant protein-1 (MCP-1) was measured from culture media. Peritoneal macrophages (PMs) from CLP rats increased release of all three mediators compared to controls. Cells from the lung vascular compartment after CLP increased release of NO, but MCP-1 release was unchanged. Levels of IL-12 were not detectable. Similarly, bronchoalveolar macrophages (BMs) of CLP rats had increased release of NO, whereas IL-12 was not detectable. Release of MCP-1 increased 48 hours after CLP. Almost all PMs and BMs possessed innate phagocytic ability that was not altered during sepsis. The percentage of cells in the lung vascular compartment that had phagocytic ability, increased 48 hours post CLP, versus controls. The authors also evaluated lung injury at 24 hours after surgery by measurement of bronchoalveolar lavage protein and LDH activity. There was an increase in both these parameters 24 hours after CLP as compared to controls. Thus, there was heterogenous and compartment-specific activation of mononuclear cells in sepsis. There was nonspecific inflammatory activation in the primary site of injury. In a remote organ (lung), the authors show for the first time that there was selective activation of NO without increased release of the proinflammatory cytokine, IL-12. Phagocytic activity was maintained in the bronchoalveolar compartment whereas in the lung vascular compartment, the percentage of phagocytic cells increased.

Chemical-chemical interaction between cyanogenic toxicants and aldehydes: a mechanism-based QSAR approach to assess toxicological joint effects

A QSAR approach was proposed to assess toxicological joint effects based on the mechanism of chemical-chemical interactions between cyanogenic toxicants and aldehydes. It has been observed that the chemical-chemical interaction between cyanogenic toxicants and aldehydes resulted in the formation of carbanion intermediates, and therefore this interaction led to different toxicological joint effects between cyanogenic toxicants and aldehydes. Analysis of this chemical-chemical interaction showed that the formation of carbanion intermediate highly depended on the charge of the carbon atom in the -CHO of aldehydes and this of the carbon atom (C*) in the carbochain of cyanogenic toxicant. By using the Hammett Constant (sigma(p)) to measure the charge of carbon atom in the -CHO of aldehydes, a mechanism-based QSAR approach (M = 0.316 - 4.386sigma(p) with r2 = 0.933, SE = 0.082, F = 55.389, p = 0.002, M = sum of toxic units) was proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aliphatic aldehydes. Another one (M = 0.978 - 0.720sigma(p) with r2 = 0.852, SE = 0.152, F = 40.148, p = 0.0001) was also proposed to assess the toxicological joint effects between alpha-hydroxy-isobutyronitrile and individual aromatic aldehydes. Lastly, by using the charge of carbon atom (C*) in the carbochain of cyanogenic toxicant, a mechanism-based QSAR model (M = -0.161 - 7.721C* with r2 = 0.847, SE = 0.227, F = 27.657, p = 0.003) was derived to assess toxicological joint effects between p-nitrobenzaldehyde and cyanogenic toxicants.

Development of a fragment constant method for estimating the mixture toxicity

Based on Group Contribution Theory, a fragment constant model to estimate mixture toxicity is proposed in this paper. The toxicity (EC50M) of 58 mixtures is determined using Photobacterium phosphoreum. Analysis of these EC50M and the mole fraction of the individual chemical fragments (Br, Cl, NO2, OH, NH2) helps work out the fragment toxicity contribution (deltaTi) to EC50M. Thus, a linear regression equation is established between the toxicity contribution deltaTi and the fragment constants of Hansch f(i), and this equation is so significant that it helps provide an approach for calculating EC50M.

Role of IFN-gamma in bacterial containment in a model of intra-abdominal sepsis

Interferon-gamma (IFN-gamma) is a specific activator of macrophage function and plays a critical role in the host immune defense to bacterial infection. In this study we examined the role of IFN-gamma in the regulation of bacterial load in the cecal ligation and puncture (CLP) model of intra-abdominal sepsis in the rat. In initial studies, levels of IL-12, MCP-1, and IFN-gamma were measured in the peritoneal lavage fluid 24 and 48 h after CLP. IL-12 and MCP-1 levels were both significantly increased at 24 h after CLP compared to sham controls and this difference was maintained at 48 h after CLP. Interestingly, IFN-gamma levels were not significantly increased 24 h after CLP, but were increased at 48 h after CLP. These results clearly suggest that although an inflammatory response had occurred 24 h post-surgery, with increases in the proinflammatory cytokine IL-12 and the potent chemotactic agent MCP-1, levels of IFN-gamma in CLP rats were similar to sham controls. To further investigate the role of IFN-gamma on the development of sepsis we examined the effect(s) of administering anti-IFN-gamma antibody on bacterial load after CLP. We show that use of anti-IFN-gamma antibody can significantly decrease bacterial load in the peritoneum. The mechanism of the effect(s) of anti-IFN-gamma is probably by increasing intestinal adhesions to seal the cecum and reduce bacterial movement into the peritoneum.

[Aneurysmal model induced by elastase]

OBJECTIVE

To induce the aneurysms by corrosion of aneurysmal wall with elastase, imitating clinical intracranial aneurysms patho-morhologically.

METHODS

The elastase-corroded arterial segments were transplanted onto lateral walls of carotid arteries. Follow-up and pathological examination of the aneurysms were made at two weeks and one month after construction.

RESULTS

The aneurysms formed by the transplantation of elastase-corroded arterial segments were found persistent or enlarge a little within one month. The aneurysms were purplish red and easy to rupture when exposed. The walls were deprived of elastic layer, and constructed by thin connective tissue.

CONCLUSIONS

The aneurysms made by transplanting elastase-corroded arterial segments are simple to built, while morphological and pathological characteristics are demonstrated good clinical mimicry, we believe our aneurysm model may well substitute the most popularly used aneurysms made of venous pouches.

Colon epithelial cell death in 2,4,6-trinitrobenzenesulfonic acid-induced colitis is associated with increased inducible nitric-oxide synthase expression and peroxynitrite production

Peroxynitrite, derived from the reaction of nitric oxide (NO(.)) with superoxide (O(2)), is a potent nitrating and oxidizing agent that can induce apoptosis in a variety of different cell types. In the present study, we investigated the possible role of peroxynitrite as a mediator of colon epithelial cell death in rat colitis. Rat colon inflammation was induced by intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS) and rats were sacrificed 24 h after TNBS administration. Expression of inducible nitric-oxide synthase (iNOS) was detected by reverse transcription-polymerase chain reaction and immunohistochemistry. The enzymatic activities of Ca(2+)-independent iNOS and Ca(2+)-dependent constitutive nitric-oxide synthase were determined biochemically. Evidence of peroxynitrite-mediated cell injury was detected by immunostaining of nitrotyrosine. Apoptosis was examined by in situ terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and DNA gel electrophoresis. To evaluate the specific contribution of peroxynitrite to the observed cell injury, a selective iNOS inhibitor, L-N(G)-[1-iminoethyl]lysine (L-NIL), was administered after TNBS induction. Morphological examination and analysis of TUNEL/cytokeratin double immunofluorescence revealed significant apoptosis in mucosal epithelial cells. Nitrotyrosine was colocalized with TUNEL, strongly demonstrating the association of peroxynitrite with the apoptotic death of colon epithelial cells. The administration of L-NIL reduced iNOS activity in 24-h lesions by 92% and also significantly attenuated both nitrotyrosine staining and apoptotic cell counts in the colon epithelium. These results strongly suggest that local elevated level of peroxynitrite produced from increased iNOS expression and activity is a major contributor to colon epithelial apoptosis during colon inflammation.

Pattern of cytokine and adhesion molecule mRNA in hapten-induced relapsing colon inflammation in the rat

We examined the mRNA expression of cytokines, chemokines, integrins, and selectins in colon lesions of rat colitis with a semi-quantitative RT-PCR assay. Rat colitis was induced by trinitrobenzene sulfonic acid (TNBS) in 50% ethanol. Within 24 h, an acute inflammation occurred with hyperemia, edema, necrosis and an intense infiltration of granulocytes in the mucosa. The lesion proceeded into a T-lymphocyte/monocyte-driven chronic inflammation for two weeks and healed in 6 weeks. An acute inflammation recurred at the same site when the recovered animals were systemically injected with TNBS. We isolated RNA from colon tissue at 24 h, 1, 2, 4, 6 weeks after TNBS treatment and from the relapsed animals. The mRNA for cytokines IL-1beta, IL-6, IL-10 and the chemokines CINC, MIP-1alpha, MCP-1 were significantly (P < 0.05) elevated and persisted for 2 weeks, decreased in 6 weeks and increased again during relapse. IFN-gamma mRNA stayed at control levels initially, but increased dramatically in the second weeks of chronic inflammation as well as in relapse. The mRNA levels of adhesion molecules, ICAM-1, VCAM-1, the mucosal homing integrin beta7 as well as P- and E-selectin were greatly enhanced between 1 and 3 weeks. The data showed that the chronically inflamed tissue expresses a time-dependent changing pattern of TH1 cytokines and adhesion molecules that maintain the infiltration and activation of inflammatory cells and tissue injury.

Re-evaluation of cellulose acetate polymer: angiographic findings and histological studies

BACKGROUND

Cellulose acetate polymer (CAP) is a new liquid embolic material that has been used experimentally in intravascular treatment of intracranial aneurysms. But this compound is still controversial in some aspects such as safety, efficiency, and histological changes. In this study, we re-evaluated the material with regard to intravascular treatment of aneurysms.

METHODS

The carotid arteries of rats and experimental aneurysms in canines were embolized with CAP. The effects of CAP were evaluated according to angiographic and histological results.

RESULTS

A strong chemo-corrosive effect was observed. This led to severe damage to vessels and rupture of two thrombosed canine aneurysm models. There were significant technical difficulties including out-flow of CAP and a high rate of occlusion of the parent arteries.

CONCLUSIONS

We conclude that currently CAP is not an ideal embolic material for intracranial aneurysms. Further tests and improvements are needed before it can be widely used clinically.