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There are about 15 species of Gracilaria reported in Vietnam. Of these, Gracilaria asiatica Zhang et Xia is being cultivated on a large scale in Northern Vietnam, which has a subtropical climate. During the rainy season, from May to October, the growth of G. asiatica is drastically reduced or even ceases due to very low salinity and high temperature. Therefore, it is important to improve the tolerance of G. asiatica to a wide range of salinity and temperatures. This paper presents the results of research on strain improvement of G. asiatica using irradiation and selection media. Three irradiation doses of 20, 60, and 100 krad were tested against the control (with no irradiation). Afterward, the seaweed biomass was cultivated on a selected medium, ESS-1, containing NaCl in concentrations of 23‰ (C1) and 0‰ (C2). The results showed that a higher survival rate of G. asiatica was observed with the 20- and 60-krad doses. The protein content and composition of selected seaweeds were analyzed and compared with the control. SDS-PAGE showed no remarkable difference in the protein composition between the control and irradiated samples. However, the 67-kDa protein band of seaweed treated with 20 and 60 krad, then grown on ESS-1 medium with 23% NaCl, had a higher density than other samples. This protein was reported to play an important role in G. asiatica, by enhancing its tolerance to variable salinity and temperature. Although the organic and inorganic content of all samples remained almost the same, the content and quality of agar extracted from irradiated seaweeds were higher than those of the controls. Due to the high amount of 3.6 anhydro-α-L-galactose combined with low amounts of sulfate found in irradiated seaweeds, the freezing and melting points of extracted agar were lower. Eventually, this resulted in higher condensation and better quality of agar, such as in its gel-forming ability. The quality of fluid agar extracted from selected seaweeds improved as shown in the remarkable decrease in Ca2+, Mg2+, and total Fe ion content, thus lowering its melting point compared with the control.

Several Vietnamese seaweed species have economic importance as food for humans, as industrial materials, as ingredients in traditional medicine, and as biofertilizers. The nutritional values of nine representative Vietnamese seaweed species were analyzed. In this report, all of the species studied are rich in proteins, lipids (especially polyunsaturated fatty acids), vitamins, pigments, and macro- and micro-elements. The effect of the physiological activities of the green alga, Ulva reticulata, on hepatic fatty acid metabolism were examined in mice. The results indicate that Vietnamese seaweeds are abundant and have high quality materials for industrial and agricultural purposes.

In order to investigate the relationship between occupational exposure to dust/chemicals (toxic gases/fumes) and chronic respiratory symptoms in Vietnam, the questionnaire standardized by the American Thoracic Society was applied to 368 subjects living in Ha Thai district of Vietnam. According to the results of multiple logistic regression analyses, the odds ratios of chronic respiratory symptoms by occupational exposure are over unity, except for the relationship between chronic cough and occupational exposure to chemicals. Especially for chronic breathlessness, significantly higher odds ratios are observed among people with a history of occupational exposure to dust or chemicals: 2.925 (95% CI: 1.130-7.574) for dust, and 3.721 (95% CI: 1.412-9.803) for chemicals. As for the interaction between occupational exposure to dust and cigarette smoking, it is considered that occupational exposure leads to an increase in chronic respiratory symptoms independent of the effects of cigarette smoking.

A cross-sectional study concerning working conditions and the fatigue complaints of assembly line workers employed in two different electronic factories (A and B) in Vietnam was conducted from August to September 1994. While general working conditions, such as noise, dust, heat and lighting, were worse in Factory B, the prevalence rate of the subjective fatigue after working time was significantly higher among workers in Factory A. Fatigue symptoms in category I (Drowsiness and dullness) were particularly apparent among workers in Factory A. More interestingly, one-third of workers in Factory A complained of stiff shoulders and low back pain. Our field observation results suggest that the ergonomic inappropriateness of the assembly line in Factory A, may be causing a high rate of subjective fatigue among workers.

Southeast Asia is a culturally, environmentally, and geographically rich, diverse, and dynamic region. Comprised of eleven countries, it spans the Indochina and Malay peninsulas and the Malay Archipelago. Five nations, Cambodia, Laos, Myanmar, Thailand, and Vietnam, are entirely on the mainland. The remaining six, Brunei, East Timor, Indonesia, Malaysia, Philippines, and Singapore, are spread across thousands of islands. Coastal zones and river deltas, piedmont zones and mountain chains, with peaks reaching heights greater than 19,000 feet, characterize the region. The land cover and land use change patterns evident in Southeast Asia are as diverse and dynamic as the political, economic, and demographic spheres in these eleven nations.

Acknowledging the disastrous implications of Climate Change for socioeconomic development, the public-private institute of the Geomatics Busines Park has since 2002 worked on a new concept coined Extreme Events Engineering and Monitoring (EEEM). In EEEM, the word ‘Engineering’ stands for all types of logic reasoning and activities as long as these help people to firmly reduce their vulnerability to extreme events.

The aim was to study the actual situation of subjective fatigue among the Vietnamese workers in factories with newly imported technology. A cross-sectional study concerning working conditions and the fatigue complaints of 389 workers who are employed in 10 Vietnamese factories with newly imported technology, was conducted from August to September 1994. About 60% of the workers were satisfied with their current working conditions. Regarding occupational risks at the workplace, heat, dust and noise were identified as the three most dangerous risks. About 46% of the workers complained about the incompatibility of the machines and equipment they were using, which are too large for Vietnamese workers. One third of all workers felt that the work pace is too rapid. Seventeen percent of the workers considered their working conditions monotonous. Finally, among 150 female workers under 40 years old, 45 workers (30.0%) complained of irregularity of menstruation. Generally these problems were more common among workers in textile factories. The prevalence rate of subjective fatigue complaints was significantly increased after work in all 30 items. The fatigue level were substantially high among workers in textile factories. Female workers in this sector had a high prevalence rate of irregularity of menstruation. There were many problems observed in the Vietnamese factories with newly imported technology. Special consideration is required to improve the working conditions of female workers in the textile industry. Both the Vietnamese government and donor countries have to give special attention to the transfer of worker-friendly technology to Vietnam, in order to achieve sound economic development.

To investigate physiological and psychological effects of industrial noise, a survey was performed on 50 female workers exposed to machinery noise [93-100 dB(A)] (noise group) and 25 female workers in less-noisy environments [71-75 dB(A)] (control group) in a textile factory in Vietnam. Urine was collected for analysis of catecholamines and cortisol. The subjects were also asked to fill out a questionnaire. Each subject was examined over 2 working days. The workers in the noise group were asked to put earplugs in their ears during the working hours of the 2nd day. On the 1st day without earplugs, urinary excretion of catecholamines in the noise group were greater than those in the control group. Cortisol in urine showed a similar tendency. Differences in catecholamine excretion between the noise group and the control group decreased on the 2nd day when the earplugs were used for attenuation of noise level in the noise group. Frequency of subjective fatigue symptoms was lower on the 2nd day than that on the 1st day in noise group, while the control group showed almost no day-difference. The results indicate that the catecholamine response to noise in workers was reduced through the use of earplugs.