A family of converters for UPS production burn-in energy recovery

This paper introduces a family of power converters for power recycling during the burn-in test of synchronized uninterruptible power supplies (UPSs) with sinusoidal output voltage. The use of the power recycler to replace the resistor load bank in the UPSs burn-in test causes great energy savings, and the optimized use of electrical energy contributes in reducing the final cost of the product. The main feature of the new circuits is their ability to draw from the UPS and to inject into the utility-grid currents with low total harmonic distortion (THD) and high power factor (PF). The new circuits operate at constant frequency and are regulated by conventional pulse width modulation (PWM) using dedicated PWM and PF controller integrated circuits developed for power supplies. Circuit operation, mathematical analysis, design example, and experimental results for discontinuous current mode (DCM) and continuous current mode (CCM) operation are provided in this paper     

Hot carrier-induced degradation of gate overlapped lightly dopeddrain (GOLDD) polysilicon TFTs

Hot-carrier injection is known to produce interface states and oxide trapped charge, which, depending upon their spatial distribution, can strongly influence the local electric fields as well as the current flow. In this work, we analyze the hot carrier-induced degradation of gate overlapped lightly doped drain (GOLDD) polysilicon thin film transistors (TFTs) and a new model, which correlates the interface state generation with the hot carrier injection current, is proposed. The defect generation rate has been assumed to depend upon the product of hot electron and hole currents J_eh, and the resulting interface state distribution has been evaluated self-consistently with the current density and carrier concentration distributions. By successive iterations, a complete spatial and time evolution of the interface state distribution has been determined, and the electrical characteristics, calculated with these interface state distributions are in good agreement with the experimental data     

Genetic Susceptibility to Periodontal Disease in Down Syndrome: A Case-Control Study

Severe periodontitis is prevalent in Down syndrome (DS). This study aimed to identify genetic variations associated with periodontitis in individuals with DS. The study group was distributed into DS patients with periodontitis (n = 50) and DS patients with healthy periodontium (n = 36). All samples were genotyped with the “Axiom Spanish Biobank” array, which contains 757,836 markers. An association analysis at the individual marker level using logistic regression, as well as at the gene level applying the sequence kernel association test (SKAT) was performed. The most significant genes were included in a pathway analysis using the free DAVID software. C12orf74 (rs4315121, p = 9.85 × 10⁻⁵, OR = 8.84), LOC101930064 (rs4814890, p = 9.61 × 10⁻⁵, OR = 0.13), KBTBD12 (rs1549874, p = 8.27 × 10⁻⁵, OR = 0.08), PIWIL1 (rs11060842, p = 7.82 × 10⁻⁵, OR = 9.05) and C16orf82 (rs62030877, p = 8.92 × 10⁻⁵, OR = 0.14) showed a higher probability in the individual analysis. The analysis at the gene level highlighted PIWIL, MIR9-2, LHCGR, TPR and BCR. At the signaling pathway level, PI3K-Akt, long-term depression and FoxO achieved nominal significance (p = 1.3 × 10⁻², p = 5.1 × 10⁻³, p = 1.2 × 10⁻², respectively). In summary, various metabolic pathways are involved in the pathogenesis of periodontitis in DS, including PI3K-Akt, which regulates cell proliferation and inflammatory response.     

Quinacrine noncompetitive inhibitor binding site localized on the Torpedo acetylcholine receptor in the open state

Open-channel blockers of the nicotinic acetylcholine receptor (nAcChR) are widely thought to act sterically by entering and "plugging" the open channel of the nAcChR. However, quinacrine, a fluorescent open-channel blocker, has been recently shown to bind to the nAcChR at a site near the lipid bilayer while the receptor is in a closed, desensitized state, suggesting that at least one open-channel blocker might act allosterically outside the channel [Valenzuela et al. (1992) J. Biol. Chem. 267, 8238]. To determine whether or not quinacrine also binds near the lipid bilayer when the receptor is in an open state, a short-range lipophilic quencher (5-doxylstearate, 5-SA) was used to assess the proximity of the nAcChR-bound quinacrine to the lipid bilayer while the receptor was transiently open by an agonist. Initial experiments using a stopped-flow instrument established the conditions required to monitor a portion of the changes in quinacrine fluorescence associated with its binding to the receptor in the open state. 5-SA (80 microM) reduced the amplitude of the rapid agonist-induced change in quinacrine emission to 44% +/- 12% of the control value, indicating that the quinacrine was binding to a site proximal to the membrane-partitioned 5-SA. Control experiments established that 5-SA had no effect on the ability of the receptor to undergo agonist-induced conformational changes, suggesting that little, if any, 5-SA distributed into the channel lumen and perturbed the functional activity of the receptor. Together, the results indicate that quinacrine binds to a site on the open receptor that is in contact with the lipid bilayer and not in the channel lumen.     

Instructional animations can be superior to statics when learning human motor skills

Based on the assumption of a working memory processor devoted to human movement, cognitive load theory is used to explore some conditions under which animated instructions are hypothesised to be more effective for learning than equivalent static graphics. Using paper-folding tasks dealing with human movement, results from three experiments confirmed our hypothesis, indicating a superiority of animation over static graphics. These results are discussed in terms of a working memory processor that may be facilitated by our mirror-neuron system and may explain why animated instructional animations are superior to static graphics for cognitively based tasks that involve human movement.     

Effect of silicon content in steel and oxidation temperature on scale growth and morphology

The effect of high silicon content in steel, 1.6 wt.%Si and 3.2 wt.%Si, and high oxidation temperatures (850–1200 °C) on scale growth rate and morphology were investigated. The steels were oxidized in a 15% humid air with short isothermal oxidation times (15 min). The scale growth rate of the non-alloyed steel follows a parabolic law with time; it is an iron diffusion controlled oxidation. The presence of silicon delays scale growth by forming a silica SiO₂ barrier layer at the scale/metal interface, this effect is more important for the steel containing 3.2 wt.%Si and induces a discontinuous scale. Silicon oxides are concentrated at the scale/metal interface; their morphology depends on the oxidation temperature. For temperatures lower than 950 °C, silica is formed. Between 950 °C and 1150 °C, fayalite (Fe₂SiO₄) grains appear in the wüstite matrix close to the scale/metal interface. For temperatures higher than 1177 °C, a fayalite–wüstite eutectic is formed; this molten phase favours iron diffusion leading to high scale growth. After cooling, a continuous fayalite layer with small wüstite grains is obtained at the scale/steel interface.     

Impact of the initial moisture level and pre-wetting history of recycled concrete aggregates on their water absorption

Initial moisture and pre-wetting method influence on the water absorption of recycled concrete aggregates (RCA) have been studied experimentally. For this purpose, RCA were pre-wetted by three methods: soaking under partial vacuum (simulating long term wetting), soaking under atmospheric pressure, and spraying (simulating short term wetting). The results show that the same initial amount of water in two samples of RCA do not lead to the same total amount of water absorbed by RCA during 5–120 min. The latter depends on the way they have been pre-wetted (either long term or short term). It is suggested that this phenomenon is related to the accessibility filled pores in the different pre-wetting methods. So, the pre-wetting history of RCA could change the amount of total water absorbed by the RCA up to 1%. When mixing and casting concrete are produced with RCA, the corresponding error in the determination of the effective water should have adverse effects on the fresh and hardened concrete characteristics. In this study real applications on mixtures of recycled concrete have been carried out, where the influence of initial moisture content and pre-wetting history of RCA on fresh recycled concrete properties (slump) have been investigated.     

Comparison of vacuum impregnation and soaking techniques for addition of the probiotic Lactobacillus acidophilus to minimally processed melon

This study aimed to evaluate the vacuum impregnation (VI) and soaking methods in the addition of Lactobacillus acidophilusLA‐3 to minimally processed melon (MPM). The melons were washed, sanitised in chlorine solution (200 mg L^?1), peeled and cutted into cubes. Lactobacillus acidophilusLA‐3 (1.4 × 10¹⁰ CFU g^?1) were added to the MPM through both techniques. The L. acidophilusLA‐3 count in MPM was similar to those commonly found in dairy products having probiotic claim, but VI was more efficient than soaking in maintaining the viability (8.61 and 7.98 Log CFU g^?1, respectively). The pH, acidity and soluble solids were not affected by probiotic culture and the incorporation technique; however, the VI affected the firmness of fruit. The MPM was within Brazilian standards for their microbiological characteristics. MPM may be used as a carrier of probiotic bacteria, being one more alternative for individuals who consume probiotic products.