Proton pump inhibitor-associated gastric polyps: a retrospective analysis of their frequency, and endoscopic, histologic, and ultrastructural characteristics

Activation of Kupffer cells by lipopolysaccharide (LPS) plays a pivotal role in the onset of pathophysiological events that occur during endotoxemia and intracellular calcium ([Ca2+]i) is involved in LPS-stimulated cytokine production. Recently, it was shown that Kupffer cells contain a glycine-gated chloride channel. Because taurine, a ubiquitous sulfur-containing beta-amino acid, acts similarly to glycine in neurons by causing hyperpolarization, it was hypothesized that taurine would act via a similar mechanism, blunting the LPS-induced increase in [Ca2+]i in Kupffer cells. To test this hypothesis, Kupffer cells were isolated from female Sprague-Dawley rats and cultured for 24 h. LPS-induced changes in [Ca2+]i were monitored fluorometrically in single cells, whereas levels of tumor necrosis factor alpha (TNF-alpha) released by Kupffer cells after exposure to LPS were measured by enzyme-linked immunosorbent assay. Taurine significantly blunted the LPS-induced increase in [Ca2+]i in a dose-dependent manner (IC50, 0.1 mM). This effect was reversed by strychnine (1 microM) and was prevented when chloride was removed from the extracellular media. Moreover, taurine increased 36Cl- uptake by Kupffer cells in a dose-dependent manner (EC50, 0.2 mM). Furthermore, strychnine (1 microM) reversed the effect of taurine on 36Cl- uptake. These results indicate that taurine activates a glycine-gated chloride channel in Kupffer cells causing chloride influx. In addition, LPS-induced TNF-alpha production was reduced by more than 40% by taurine, an effect that was also reversed by strychnine. In conclusion, taurine blocks the increase in [Ca2+]i due to LPS and significantly reduces TNF-alpha production by mechanisms involving chloride influx into the Kupffer cell.     

Inverse Resolution of the Heat- Transfer Equation: Application to Steel and Aluminum Alloy Quenching

Two applications of the numerical method for the inverse heat conduction problem are presented. This numerical method calculates the surface temperature and heat flux using an internal experimental temperature evolution. In the case of aluminum alloys, the question of stability and sensitivity to error measurements is investigated and applied to actual quench cooling. For steel application (high heating and cooling rates), a new calculation procedure is developed to solve the problem of solution stability due to the nonmonotonous initial temperature profile generated by the superficial heating. This new calculation procedure allows the martensite tempered zones to be explained and localized.     

Changing patterns of gap junctional intercellular communication and connexin distribution in mouse epidermis and hair follicles during embryonic development

This paper is concerned with whether transport accident risk tends to peak at particular times, in relation to both time of day and time on task, and with the underlying causes of such peaks. Macro-analyses confirmed the presence of a clear circadian (ca 24 hour) rhythm in road accident risk with a major peak at ca 03:00 but suggested that this rhythm could not be entirely accounted for in terms of drivers falling asleep at the wheel. Sleep propensity clearly shows a pronounced circadian rhythm and performance efficiency in wakeful subjects shows a similar trend implying that the 03:00 road accident peak may simply reflect lowered performance capabilities. However, there are 'residual' peaks in accidents at certain times of day that are difficult to account for in terms of circadian rhythmicity. It is suggested that these may reflect a time on task effect which shows a pronounced, but transient, 2-4 hour peak in risk. Only when individuals had been on duty for 12 hours or more did the risk exceed that found during the 2-4 hour peak. While an explanation for this transient peak is offered, the underlying reason for it is, as yet, uncertain and clearly warrants investigation in view of its practical implications. It is concluded that there are 'black times' when accidents are far more likely and that there is a strong need to investigate possible countermeasures.     

Frequency Interval Gramians Based Structure Preserving Model Order Reduction for Second Order Systems

A new structure preserving model order reduction technique for second order systems in limited frequency interval is presented. Frequency limited Gramians (FLGs) and corresponding continuous time algebraic lyapunov equations (CALEs) are developed. For solution of CALEs and Cholesky factorization of FLGs, computationally efficient approximation scheme is proposed. Multiple transformations based on balancing of frequency limited position or velocity Gramians are defined in order to compute Hankel singular values (HSVs). Frequency limited second order balanced truncation based on magnitudes of HSVs is performed for order reduction. Moreover, stability conditions for reduced order models (ROMs) are stated and algorithms for achieving stability in ROMs are proposed. Results are compared with existing technique to certify the usefulness of the proposed technique.     

Enhancement of Critical Current Density of MgB<Subscript>2</Subscript> by Glutaric Acid Doping: a Simultaneous Improvement on the Intrinsic and Extrinsic Properties

In this study, we report an enhancement of critical current density of bulk MgB₂ superconductors by glutaric acid (C₅H₈O₄) doping. The effects of glutaric acid doping on MgB₂ lattice resulted in a record self-field J _c of the order of 10⁶ A/cm². A simultaneous improvement in the connectivity, pinning force, and H _c2 is the major factor that determined excellent J _c performance. X-ray diffraction analysis showed that samples were single-phase MgB₂ with a minor trace of impurities. A dramatic change in grain morphology and homogeneity in grain distribution was found in the SEM images of doped samples. We observed that homogeneity in grain distribution played a crucial role in the connectivity and the upper critical field (H _c2) of the doped samples. We were able to introduce a new dopant through a two-step mixing approach which is suitable to overcome the degradation of low field and self-field J _c reported for carbon-doped MgB₂ superconductor samples.     

Novel Design of UWB Jeans Based Textile Antenna for Body-Centric Communications

This research presents an ultra-wideband (UWB) textile antenna design for body-centric applications. The antenna is printed on a 1 mm thick denim substrate with a 1.7 relative permittivity. The jeans substrate is sandwiched between a partial ground plane and a radiating patch with a Q-shaped slot. The slotted radiating patch is placed above the substrate and measures 27.8 mm × 23.8 mm. In free space, the antenna covers the ultra-wideband spectrum designated by the Federal Communication Commission (FCC). Various parameters of the antenna design were changed for further performance evaluation. Depending on the operating frequency, the antenna's realized gain varied from 2.7 to 5 dB. The antenna achieved high radiation efficiency with an omnidirectional radiation pattern. A parametric study was performed in research on varying antenna substrates and other components of the antenna. The three outermost layers of the human body are used to model a human phantom for on-body simulation. After that, the antenna was placed at five different distances from the phantom. The findings demonstrate that at close distances to the phantom, the antenna's gain and efficiency at lower frequencies are reduced. The antenna's radiation efficiency and gain were much higher at higher frequencies for distances greater than 6 mm. Compared to free space, the antenna's radiation pattern was more omnidirectional, especially at higher frequencies. This antenna is novel, compact and has an ultra wide bandwidth, a maximum of 94.60% radiation efficiency and a 5 dBi gain that will make it a good candidate for body-centric communications.     

An economic model predictive control approach to integrated production management and process operation

Managing production schedules and tracking time‐varying demand of certain products while optimizing process economics are subjects of central importance in industrial applications. We investigate the use of economic model predictive control (EMPC) in tracking a production schedule. Specifically, given that only a small subset of the total process state vector is typically required to track certain scheduled values, we design a novel EMPC scheme, through proper construction of the objective function and constraints, that forces specific process states to meet the production schedule and varies the rest of the process states in a way that optimizes process economic performance. Conditions under which feasibility and closed‐loop stability of a nonlinear process under such an EMPC for schedule management can be guaranteed are developed. The proposed EMPC scheme is demonstrated through a chemical process example in which the product concentration is requested to follow a certain production schedule. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1892–1906, 2017     

Synthesis and characterization of polyethylene glycols conjugated to polybutylcyanoacrylate nanoparticles

This study aimed to evaluate the cytotoxicity effects of various polyethylene glycols (PEGs), and construction and characterization of polybutylcyanoacrylate (PBCA) nanoparticles. Cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on rat glioma C6 cell line, and PBCA nanoparticles were prepared by emulsion polymerization method. Also, the nanoparticles were characterized by dynamic light scattering and scanning electron microscopy. The findings showed that PEGs were approximately safe and cytotoxicity was inversely proportional with their molecular weights. In addition, the size of nanoparticles were increased with reducing molecular weights of PEGs. PEGs with negligible cytotoxicity and stabilizing functionality were demonstrated in this study.