Combined Treatment on an Al Surface to Improve the Metal-Polymer Adhesion Strength

The development of mobile industries and urban transportation today requires nanotechnology for research and processing of metallic surfaces. Here, aluminum alloys (Al) are the most common material with the best physical properties that need to be treated. The advantages of Al in manufacturing are obvious; however, the Al surface is sensitive to the presence of acid or base, and thus protecting the Al surface is mandatory. In this study, Al surfaces have been subjected to a new surface treatment process that includes sandblasting, anodizing, and subsequent post-etching steps. The treated surfaces are evaluated by surface morphology including contact angle measurement and polymer adhesion strength. The adhesion strength of blasted Al-polymer assemblies with and without an anodizing step have been performed with a single lap shear test. This clearly shows the profound effect of the combined treatment process. The results reveal that a combination of high surface roughness and area as well as a thick Al₂O₃ layer with micro-cavities created by a post-etch step can significantly improve the adhesion strength of the Al-polymer. This, in turn, enhances the quality of and longevity of Al surface in production and application.

Assessment of nurses' nutritional knowledge regarding therapeutic diet regimens

Metabolic diseases and cardiovascular disease (CVD), the incidence of which is currently increasing in Korea, can be managed well with dietary education and modification. However, it has yet to be established whether nurses have sufficient knowledge to impart appropriate nutritional counseling to patients with these diseases. Our study involved 506 nurses working at Asan Medical Center, Samsung Medical Center, and Seoul National University Hospital between March and May, 2006. The questionnaire was comprised of 42 diet-related questions pertaining to diabetes, obesity, and CVD. Nurses' correct-response rate for overall nutritional knowledge was worse than reported in Western countries (58.4%), and particularly so with regard to obesity and CVD. Although many nurses were aware of the therapeutic aspects of nutrients in relation to CVD, most of them had limited knowledge about low-cholesterol diets and sources of water-soluble fiber, fatty acids and the specific food items that prevent CVD. Our results suggest that there is an urgent need to update the contents of nutrition education for nurses to reflect the current changes in the Korean diet and the increasing incidence of metabolic diseases and CVD.

Effect of pregnancy on food consumption and consciousness factors associated with food satisfaction

To examine the effect of pregnancy on food consumption, we surveyed the recall of past experience of two groups of women, those who had been pregnant (PY, n=188) and those who never had (PN, n=111), regarding their food consumption and related dietary behaviors. The questionnaire, answered with regard to potato chips, contained 135 objective components expressing sensorial stimuli and 103 subjective consciousness components, including knowledge, education, faith, memory, experience, lifestyle, family values, imagination, and mental state. In the PY group, 86% of the women change in food consumption and preference during pregnancy, and 60% experienced decreased food consumption during emesis gravidarum (EG). The change in food consumption during and after periods of EG was influenced by the number of previous births for the women in the PY group; in women pregnant for a second or third time, the change in food intake was less than during the previous pregnancy. The difference in food satisfaction with regard to potato chips between the PY and PN groups showed that overall food satisfaction could not be explained by a combination of objective sensorial components; the only objective components that were directly related to overall satisfaction were taste and texture. Multidimensional analysis with strength of sensorial stimulus, preference, and overall satisfaction revealed differences in patterns between the PN and PY groups. The effect of the consciousness components on food preference and satisfaction was comparable to that of the sensorial components.

Glucosylceramide: a marker for multiple-drug resistant cancers

BACKGROUND

Multiple-drug resistance (MDR) is a major reason for chemotherapy failure. Herein we describe glucosylceramide, a new marker for MDR.

METHODS

Cellular lipids were analyzed in three human MDR cancer cell lines and their drug-sensitive counterparts. Analysis of glucosylceramide was also performed in six melanoma specimens and one breast tumor specimen obtained from patients who had undergone chemotherapy. Glucosylceramide, analyzed by mass and by cellular utilization of radiolabeled precursor ([3Hpalmitic acid), was isolated by lipid extraction techniques and resolved from other components by thin-layer chromatography.

RESULTS

Glucosylceramide was present consistently in all MDR cell lines and was absent, or present only at very low levels, in the corresponding drug-sensitive cells. Examination of human tumor specimens documented presence of the marker in all patients who had failed chemotherapy, and absence of the marker in each of the patients with known clinical response to chemotherapy. The response to chemotherapy was followed for a median of 8 months in melanoma patients and for 22 months in the breast cancer patient.

CONCLUSION

These findings suggest that glucosylceramide may hold clinical significance for the early identification of drug-resistant tumors.