Axiom-based Potential Functional Failure Analysis for Risk-free Design

Abstract. Quality and reliability of product is not established completely in detail design process, but is brought out essentially in the course of conceptual design. A potential functional failure analysis method to improve reliability of product based on design axiom in the stage of conceptual design was introduced in this paper. This method provided designers with an analytical and non-probabilistic tool to evaluate the result of conceptual design from the opinion of design axioms. Functional failure modes can be identified by function analysis based on the ideality axiom, the independence axiom and the information axiom. These potential functional failures point out working direction for the latter improving design. A speedy cutting off valve in the TRT (Top Gas Pressure Recovery Turbine) system is studied as an example to illustrate this method's potential

The growing world of expansins.

; Expansins are cell wall proteins that induce pHdependent wall extension and stress relaxation in a characteristic and unique manner. Two families of expansins are known, named a-and b-expansins, and they comprise large multigene families whose members show diverse organ-, tissue-and cell-specific expression patterns. Other genes that bear distant sequence similarity to expansins are also represented in the sequence databases, but their biological and biochemical functions have not yet been uncovered. Expansin appears to weaken glucan-glucan binding, but its detailed mechanism of action is not well established. The biological roles of expansins are diverse, but can be related to the action of expansins to loosen cell walls, for example during cell enlargement, fruit softening, pollen tube and root hair growth, and abscission. Expansin-like proteins have also been identified in bacteria and fungi, where they may aid microbial invasion of the plant body. Keywords: Cell growth -Cell walls -Expansins -Wall loosening proteins. Abbreviations: EXP, a-expansin; EXPB, b-expansin; EXPL, expansin-like; EXPR, expansin-related; Zea m 1, b-expansin and group 1 allergen of maize pollen

Overexpression of Ferredoxin, PETF, Enhances Tolerance to Heat Stress in Chlamydomonas reinhardtii

Reactive oxygen species (ROS) produced by plants in adverse environments can cause damage to organelles and trigger cell death. Removal of excess ROS can be achieved through the ascorbate scavenger pathway to prevent plant cell death. The amount of this scavenger can be regulated by ferredoxin (FDX). Chloroplastic FDXs are electron transfer proteins that perform in distributing photosynthetic reducing power. In this study, we demonstrate that overexpression of the endogenous photosynthetic FDX gene, PETF, in Chlamydomonas reinhardtii could raise the level of reduced ascorbate and diminish H2O2 levels under normal growth conditions. Furthermore, the overexpressing PETF transgenic Chlamydomonas lines produced low levels of H2O2 and exhibited protective effects that were observed through decreased chlorophyll degradation and increased cell survival under heat-stress conditions. The findings of this study suggest that overexpression of PETF can increase the efficiency of ROS scavenging in chloroplasts to confer heat tolerance. The roles of PETF in the downregulation of the ROS level offer a method for potentially improving the tolerance of crops against heat stress