Exogenous Asymmetric Dimethylarginine (ADMA) in Pathogenesis of Ischemia-Reperfusion-Induced Gastric Lesions: Interaction with Protective Nitric Oxide (NO) and Calcitonin Gene-Related Peptide (CGRP)

Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide (NO) synthesis inhibitor and pro-inflammatory factor. We investigated the role of ADMA in rat gastric mucosa compromised through 30 min of gastric ischemia (I) and 3 h of reperfusion (R). These I/R animals were pretreated with ADMA with or without the combination of l-arginine, calcitonin gene-related peptide (CGRP) or a small dose of capsaicin, all of which are known to afford protection against gastric lesions, or with a farnesoid X receptor (FXR) agonist, GW 4064, to increase the metabolism of ADMA. In the second series, ADMA was administered to capsaicin-denervated rats. The area of gastric damage was measured with planimetry, gastric blood flow (GBF) was determined by H₂-gas clearance, and plasma ADMA and CGRP levels were determined using ELISA and RIA. ADMA significantly increased I/R-induced gastric injury while significantly decreasing GBF, the luminal NO content, and the plasma level of CGRP. This effect of ADMA was significantly attenuated by pretreatment with CGRP, l-arginine, capsaicin, or a PGE₂ analogue. In GW4064 pretreated animals, the I/R injury was significantly reduced and this effect was abolished by co-treatment with ADMA. I/R damage potentiated by ADMA was exacerbated in capsaicin-denervated animals with a further reduction of CGRP. Plasma levels of IL-10 were significantly decreased while malonylodialdehyde (MDA) and plasma TNF-α contents were significantly increased by ADMA. In conclusion, ADMA aggravates I/R-induced gastric lesions due to a decrease of GBF, which is mediated by a fall in NO and CGRP release, and the enhancement of lipid peroxidation and its pro-inflammatory properties.     

Tunneling/shear force microscopy using piezoelectric tuning forks for characterization of topography and local electric surface properties

Characterization of novel nanoelectronic structures and materials requires advanced and high-resolution diagnostic methods. In this article new approach for high sensitivity measurements of electric surface properties using scanning probe microscopy is presented. In this procedure topography and tunneling current flowing between the metallic tip and the surface are observed simultaneously. In our design piezoelectric tuning fork equipped with metallic tip in shear force microscope is used.     

Reforming of Model Gasification Tar Compounds

Gasification tar, causing various process equipment problems, is an undesirable product during biomass gasification therefore catalysts for its decomposition are needed. Toluene as a model tar compound was tested on steam reforming reaction using ceria-zirconia based Ni and Co catalysts.     

Properties of scaffolds based on chitosan and collagen with bioglass 45S5

Scaffolds based on chitosan (CTS), collagen (Coll) and glycosaminoglycans (GAG) mixtures cross‐linked by tannic acid (TA) with bioglass 45S5 addition were obtained with the use of the freeze‐drying method. The prepared scaffolds were characterised for morphology, mechanical strength and degradation rate. Moreover, cell viability on the obtained scaffolds was measured with and without the presence of ascorbic acid and dexamethasone. The main purpose of the research was to compare the effectiveness of bioglass 45S5 influence on the physicochemical and biological properties of scaffolds. The results demonstrated that the scaffolds based on the blends of biopolymers cross‐linked by TA are stable in an aqueous environment. Scanning electron microscope images allowed the observation of a porous scaffold structure with interconnected pores. The addition of bioglass nanoparticles improved the mechanical properties and decreased the degradation rate of composite materials. The biological properties were improved for 20% tannic acid addition compared to 5%. However, the addition of bioglass 45S5 did not change to cells response significantly.Inspec keywords: biomedical materials, drying, porous materials, freezing, tissue engineering, proteins, nanofabrication, bone, scanning electron microscopy, polymers, molecular biophysics, cellular biophysics, nanoparticles, porosityOther keywords: chitosan, collagen, glycosaminoglycans, bioglass 45S5 addition, freeze‐drying method, degradation rate, ascorbic acid, dexamethasone, physicochemical properties, biological properties, porous scaffold structure, bioglass nanoparticles, mechanical properties, tannic acid addition, scanning electron microscopy     

Rapid Growth Cone Uptake and Dynein‐Mediated Axonal Retrograde Transport of Negatively Charged Nanoparticles in Neurons Is Dependent on Size and Cell Type

Nanoparticles (NPs) are now used in numerous technologies and serve as carriers for several new classes of therapeutics. Studies of the distribution of NPs in vivo demonstrate that they can be transported through biological barriers and are concentrated in specific tissues. Here, transport behavior, and final destination of polystyrene NPs are reported in primary mouse cortical neurons and SH‐SY5Y cells, cultured in two‐compartmental microfluidic devices. In both cell types, negative polystyrene NPs (PS(?)) smaller than 100 nm are taken up by the axons, undergo axonal retrograde transport, and accumulate in the somata. Examination of NP transport reveals different transport mechanisms depending on the cell type, particle charge, and particle internalization by the lysosomes. In cortical neurons, PS(?) inside lysosomes and 40 nm positive polystyrene NPs undergo slow axonal transport, whereas PS(?) outside lysosomes undergo fast axonal transport. Inhibition of dynein in cortical neurons decreases the transport velocity and cause a dose‐dependent reduction in the number of accumulated PS(?), suggesting that the fast axonal transport is dynein mediated. These results show that the axonal retrograde transport of NPs depends on the endosomal pathway taken and establishes a means for screening nanoparticle‐based therapeutics for diseases that involve neurons.     

Polymer Nanosheet Containing Star‐Like Copolymers: A Novel Scalable Controlled Release System

Poly(ε‐caprolactone) (PCL)‐based nanomaterials, such as nanoparticles and liposomes, have exhibited great potential as controlled release systems, but the difficulties in large‐scale fabrication limit their practical applications. Among the various methods being developed to fabricate polymer nanosheets (PNSs) for different applications, such as Langmuir–Blodgett technique and layer‐by‐layer assembly, are very effort consuming, and only a few PNSs can be obtained. In this paper, poly(ε‐caprolactone)‐based PNSs with adjustable thickness are obtained in large quantity by simple water exposure of multilayer polymer films, which are fabricated via a layer multiplying coextrusion method. The PNS is also demonstrated as a novel controlled guest release system, in which release kinetics are adjustable by the nanosheet thickness, pH values of the media, and the presence of protecting layers. Theoretical simulations, including Korsmeyer–Peppas model and Finite‐element analysis, are also employed to discern the observed guest‐release mechanisms.     

Ultra-long-haul 40-Gbit/s-based DWDM transmission using optically prefiltered CS-RZ signals

Ultra-long-haul 42.7-Gbit/s-based dense wavelength-division multiplexing (DWDM) transmission using optically prefiltered carrier-suppressed return-to-zero (CS-RZ) signal has been experimentally investigated. First, we have numerically and experimentally evaluated the impact of 3-dB bandwidth and filter detuning of bandlimiting filters on the 42.7-Gbit/s CS-RZ signal in back-to-back condition. We found that the asymmetrically filtered CS-RZ signal had a great potential for ultra-DWDM applications. Next, we have numerically and experimentally investigated the basic transmission characteristics of a 45-GHz-wide prefiltered CS-RZ signal, such as the robustness against residual dispersion, nonlinear effects, and PMD, and have confirmed that the prefiltered CS-RZ signal had less tolerance against fiber nonlinearity than an unfiltered CS-RZ signal. Finally, we have experimentally investigated the optimum filtering condition for 65- or 45-GHz-wide prefiltered CS-RZ signals in the ultra-long-haul DWDM transmission and have conducted the 70- and 50-GHz spaced 32 /spl times/ 42.7Gbit/s transmission using prefiltered CS-RZ signals. Through these experiments, we have confirmed the effectiveness of prefiltered CS-RZ signal ultra-long-haul DWDM transmission.     

A GIS approach to ingest Meteosat Second Generation data into the Local Analysis and Prediction System

The Local Analysis and Prediction System (LAPS) is modified to ingest Meteosat Second Generation (MSG) data for cloud analysis. A first study is conducted to test the actual performance of the weather analysis software after new satellite bands are introduced. Results show that the system provides high quality cloud products such as cloud mask, cloud top height and cloudiness. A comparison with products from EUMETSAT’s Nowcasting SAF shows a general underestimation of the LAPS product although the results are not conclusive. The study shows the potential of MSG data in refining the mesoscale analyses produced by LAPS. Moreover the software tools, based on open source codes for geolocation and geographical information systems, written for the transformation of MSG data into input files for LAPS have demonstrated a great flexibility and ease of use. The study opens up an avenue for successive validation and refinement of the analyses together with their improved implementation for operational nowcasting and very short range forecasting applications.