Impact of urban expansion on the air pollution landscape: A case study of Hanoi, Vietnam.

The rapid urban expansion of Hanoi over the last few decades has transformed a lot of agricultural land into urban land uses accompanying pollution by traffic, industrial, and residential emission sources. In this work, the impact of urban expansion on the air pollution landscape has been assessed using the NO2 and SO2 ambient concentrations measured by passive diffusion samplers at 176 sites across the nine urban and the five peri-urban districts of Hanoi spanning an area of 921 km2. The NO2 values ranged from 5.5 to 70 µg m-3 with an arithmetic mean of 34.3 µg m-3. The corresponding figures for SO2 are 1, 51, and 14.5 µg m-3. The pollutant concentrations decrease from the city center outward, reflecting the history of urban expansion with the city fringe being urbanized in the 1980s and the peri-urban area having undergone development from the early 1990s. The pollution landscapes show elevated concentration levels in the recently built-up areas at 6, 10, and 21 km from the city center. The NO2 and SO2 digital maps generated from monitoring data by the kriging technique show numerous traffic and industrial emission hot spots in the peri-urban area. As revealed by the land use regression models, the factors driving the spatial variations of pollutant concentrations across the city include the population density, the road density, and the distances of the monitoring site to the urban center and the nearest roadway.

Highly Pathogenic Avian Influenza Virus A/H5N1 Infection in Vaccinated Meat Duck Flocks in the Mekong Delta of Vietnam.

We investigated episodes of suspected highly pathogenic avian influenza (HPAI)-like illness among 12 meat duck flocks in two districts in Tien Giang province (Mekong Delta, Vietnam) in November 2013. In total, duck samples from 8 of 12 farms tested positive for HPAI virus subtype A/haemagglutinin 5 and neuraminidase 1 (H5N1) by real-time RT-PCR. Sequencing results confirmed clade of 2.3.2.1.c as the cause of the outbreaks. Most (7/8) laboratory-confirmed positive flocks had been vaccinated with inactivated HPAI H5N1 clade 2.3.4 vaccines <6 days prior to onset of clinical signs. A review of vaccination data in relation to estimated production in the area suggested that vaccination efforts were biased towards larger flocks and that vaccination coverage was low [21.2% ducks vaccinated with two shots (range by district 7.4-34.9%)]. The low-coverage data, the experimental evidence of lack of cross-protection conferred by the currently used vaccines based on clade 2.3.4 together with the short lifespan of meat duck flocks (60-70 days), suggest that vaccination is not likely to be effective as a tool for control of H5N1 infection in meat duck flocks in the area.

Treatment with protein kinase C activator is effective for improvement of male pronucleus formation and further embryonic development of sperm-injected oocytes in pigs.

To assist the process of oocyte activation, which is essential for promotion of fertilization events, i.e., resumption of meiosis, extrusion of the second polar body and formation of the pronucleus (PN), artificial stimuli such as an electrical pulse have been applied to porcine oocytes after injection of sperm. However, the efficiency of fertilization and embryonic development remains low. It is well known that in vertebrates, inactivation of mitogen-activated protein (MAP) kinase is required for oocyte activation. We have hypothesized that even after electrical stimulation of sperm-injected oocytes, MAP kinase may not be inactivated. As it has been reported that MAP kinase activity is regulated by protein kinase C, we examined the effectiveness of phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator, for improvement of fertilization and embryonic development of sperm-injected porcine oocytes. First, we examined the concentrations (0, 0.01, 0.1, 1, and 10 µM) and durations (0, 1, 3, 5 hours) of PMA treatment that were efficient for the extrusion of two polar bodies and formation of two PNs (2PB+2PN) and embryonic development. When the sperm-injected oocytes were treated with 0.01-µM PMA for 3 hours after electrical stimulation, the rates of 2PB+2PN and embryonic development were higher than those in the other treatment groups. We then examined the effect of PMA treatment (0.01 µM, 3 hours) on MAP kinase activity. Unexpectedly, after electrical stimulation, the activity remained low until PN formation, irrespective of whether or not the oocytes had been treated with PMA. On the other hand, transformation of the injected sperm nucleus into the male PN was accelerated after the PMA treatment. Our present results suggest that the low efficiency of fertilization and embryonic development in sperm-injected oocytes is not due to high activity of MAP kinase but due to poor transformation of the injected sperm nucleus into the male PN. Furthermore, a combination of electrical stimulation and PMA is a fairly effective artificial protocol for promoting 2PB+2PN and embryonic development in sperm-injected porcine oocytes.