Surface relief produced by diffusion induced boundary migration in Cu-Zn

Experimental observations are presented that demonstrate that diffusion induced grain boundary migration in copper foils exposed to zinc vapor, from a Cu-15 pct Zn alloy, can be studied directly after treatment without etching. The general characteristics of migration are in accord with previous investigations, but novel changes in the surface topography are described. Pits were formed on the surface of areas swept by boundary migration; also, the surface was often converted into a series of corrugations. The formation of pits suggests that the grain boundary diffusivity of zinc exceeds that of copper. The corrugations are believed to indicate that boundaries sometimes move in an intermittent manner.     

Effect of salts on the rheology of hydrocolloids from mulberry (Morus alba L.) leaves in concentrated domain

Rheological properties of 2–8% mulberry leaf hydrocolloids extracted by hot water (Hw) or sodium bicarbonate (Alk or Alk-v) were evaluated. Steady shear rheological results of mulberry leaf hydrocolloids indicated the structural behavior with a Newtonian viscosity at low shear rate and shear-thinning behavior over intermediate to high shear rate regime. As simulated by Carreau model, the characteristic time constant of mulberry leaf hydrocolloids increased, but the power-law behavior index decreased with increasing concentration. Results from the dynamic rheological experiments revealed that the behavior of 2% mulberry leaf hydrocolloid solutions were characteristic concentrated polymer solution. However, as the concentration was raised up to 4–8%, a gel-like behavior may occur depending on the extraction methods, possibly owing to the formation of aggregates at high polymer concentration. Furthermore, rheological properties of Alk and Alk-v were generally higher than those of Hw. Though mulberry leaf hydrocolloids were ionic polymers, the rheological properties in concentrated domain were not influenced pronouncedly by the addition of 0–200 mM of NaCl, KCl or MgCl₂. In contrast, under sufficiently high CaCl₂ concentration (68 mM or 200 mM for alkaline extracted and water extracted mulberry leaf hydrocolloids, respectively), formation of a three-dimensional gel network was observed, possibly due to the cross-linking of Ca²⁺ with carboxyl groups of mulberry leaf hydrocolloids in addition to charge screening effects.     

Health impacts associated with the implementation of a national petrol-lead phase-out program (PLPOP): evidence from Taiwan between 1981 and 2007

Background and objective

In 1981, a petrol-lead phase-out program (PLPOP) was launched in Taiwan for the abatement of environmental lead emissions. The present study was set out to examine whether the reduction of environmental lead emissions would result in the decrease in mortality rates of various diseases based on national data between 1981 and 2007.

Method

The national mortality data were obtained from the Office of Statistics of the Taiwan Department of Health (Taiwan DOH). Standardized mortality ratios (SMRs) were calculated based on 2000 WHO world standard population. Gasoline consumptions were obtained from the Bureau of Energy.

Results

The mean blood lead levels (BLLs) had decreased dramatically from approximately 20.14 μg/dl in the leaded petrol phase to 3 μg/dl or lower in the unleaded petrol phase. From 1981 to 2007, the mortality (per 100,000 people) was decreased from 146.2 to 43.8 for cerebrovascular disease, from 85.3 to 44.4 for heart disease, from 35.4 to 6.6 for hypertensive disease, from 21.3 to 17.3 for nephrosis, and from 810.2 to 491.6 for all causes. By taking the confounders (including economic growth rate, per capita income, tobacco consumption, and medical resources) into account, the decreases in SMRs for all causes, cerebrovascular disease, and nephrosis were found to be highly correlated with the decrease in petrol lead emissions (p-values = 0.001, < 0.001, 0.020, respectively).

Conclusion

Our results clearly show that the implementation of the PLPOP was associated with a decline in mortality rates in several diseases that have been associated with lead exposure, even after adjustment for a number of relevant confounders.     

Possible association between nickel and chromium and oral cancer: a case-control study in central Taiwan

Oral cancer is one of the most common cancers in Taiwan. Changhua County, in central Taiwan, has an extremely high prevalence of oral cancer, along with a high concentration of metal-related industries and soil metal contamination. The aim of this study was to clarify the possible association between metals and oral cancer within this specific area. This study recruited 101 oral cancer patients and 104 controls from the Changhua Christian Hospital. All subjects completed a questionnaire that asked about demographic information; cigarette, alcohol, and betel quid use; and environmental and occupational exposure history. Blood samples were collected and tested for metal concentrations with inductively coupled plasma mass spectrometry. A multiple logistic regression model illustrated that oral cancer was significantly associated with the blood levels of nickel and chromium (both with P < 0.0001) after controlling for potential confounders. This study suggested a potential role of these two metals in the mechanism of oral cancer development.     

On a novel press system with six links for precision deep drawing

The objective of this paper is to propose a novel press system with six links for precision deep drawing, and verify its feasibility. First, the system is presented and its advantages are discussed. Then, the kinematic analysis of the system is obtained by examining the geometry of the design. Moreover, kinematic dimensions of the variable coupling are found by using optimization method. Furthermore, the proposed approach is illustrated by a design example, its solid model for the proposed design is established, and then kinematic simulation is performed by ADAMS software. Finally, a prototype and an experimental setup are established, and the experiment is conducted. The results show that the proposed new mechanism is feasible and of reasonable accuracy. In addition, it has the advantages of easy manufacture, lower cost, higher precision, and easy adjustability.     

Considerations and preliminary design of patient exposure registry

To aid in protecting patients from unnecessary exposures and to reduce radiation burdens to the public, a system for tracking a patient's medical exposure history and related radiation doses would be a useful tool. A patient-centred exposure registry, the Patient Exposure Registry (PER), is a mechanism that provides this tracking. This article outlines the objectives of the proposed Canadian PER together with considerations and preliminary design of the registry. Implementation strategy is discussed. The strategy will allow many initiatives progressing in parallel such as backward data mining and forward development in order to make this important registry a reality in the near future.     

Identical-length nanowire arrays in anodic alumina templates

Arrays of nanowires with identical length are fabricated by using ultrasound to remove the length fluctuation among nanowires, which are deliberately grown in burette-shaped nanochannels on an anodic anumina film. The process allows the fabrication of 10 micron Ag-nanowire arrays with length fluctuation as small as 0.09%. By integrating the process with a focused-ion-beam-based lithographic method to grow nanowires into selective nanochannels in an array, we fabricate arrays of uniform-length nanowires that are arranged in a custom-designed lateral geometry. The ability to fabricate such artificial nanomaterials paves the way for the exploitation of their unusual optical, electrical, and thermal properties.