Background The use of antenatal care (ANC) varies between countries and in different settings wit... more Background The use of antenatal care (ANC) varies between countries and in different settings within each country. Most previous studies of ANC in Vietnam have been cross-sectional, and conducted in rural areas before the year 2000. This study aims to compare the pattern and the adequacy of ANC used in rural and urban Vietnam following two cohorts of pregnant women. Methods A comparative study with two cohorts comprising totally 2132 pregnant women were followed in two health and demographic surveillance sites, one rural and one urban in Hanoi province, Vietnam. The women were quarterly interviewed using a structured questionnaire until delivery. The primary information obtained was the number and the content of ANC visits. Results Almost all women reported some use of ANC. The average number of visits was much lower in the rural setting (4.4) than in the urban (7.7). In the rural area, 77.2% of women had at least three visits and 69.1% attended ANC during the first trimester. The corresponding percentages for the urban women were 97.2% and 97.2%. Only 20.3% of the rural women compared to 81.1% of the urban women received all core ANC services. As a result, the adequate use of ANC was 5.2 times in the urban than in the rural setting (78.3% compared to 15.2%). Nearly all women received ultrasound examination during pregnancy with a mean value of 6.0 scans per woman in the urban area and 3.5 in the rural. Most rural women used ANC at commune health centres and private clinics while urban women mainly visited public hospitals. Expenditure related to ANC utilization for the urban women was 7.1 times that for the urban women. Conclusion The women in the rural area attended ANC later, had fewer visits and received much fewer services than urban women. The large disparity in ANC adequacy between the two settings suggests special attention for the ANC programme in rural areas focusing on its content. Revision and enforcement of the national guidelines to improve the behaviour and practice of both users and providers are necessary.
This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil e... more This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil erosion in steep-slope ecosystems in Northern Vietnam. We investigated the effects of Amynthas khami, an anecic species producing above-ground casts of prominent size, on water infiltration and soil detachment along a land-use intensification gradient: a cultivation of cassava (Mahinot esculenta; CAS), a plantation of Bracharia (Bracharia ruzziziensis; BRA), a fallow (FAL), a fallow after a forest of Eucalyptus sp. (EUC) and a plantation of trees (Acacia mangium and Venicia Montana; FOR). Two scales of studies were considered: (i) at the structure scale (cm2), a water runoff simulation was used to differentiate the effects of casts, free biogenic aggregates that previously belong to casts, and free physicogenic aggregates; (ii) at the station levels, 1-m2 plots were used to determine runoff and soil detachment rates during the rainy season in 2005.A. khami was sensitive to land-use management. Earthworm density was low in all the fields (0–1 ind m− 2). The highest densities were found in EUC and FOR and no individual was found in CAS. As a consequence, soil surface in EUC and FOR was covered with casts and free biogenic aggregates (approximately 22 and 8 kg m− 2, respectively). In FAL and BRA, casts covered the soil only sparsely with < 3 kg m− 2. In CAS, soil surface was characterized by free physicogenic aggregates that might be produced by human activity or endogeic earthworms through tillage (approximately 1 kg m− 2). Water runoff simulation clearly showed an enhancement of water infiltration with earthworm casting activity. Water runoff was more decreased with casts (R2 = 0.26) than free biogenic aggregates (R2 = 0.49). Conversely, physicogenic aggregates were not associated with higher water infiltration. Analyses of runoff and soil detachment rates during the rainy season underlined that the more land-use type have aggregates on soil surface and the less important is surface runoff (R2 = 0.922). Conversely, no relation occurred between aggregates and soil detachment rate. While above-ground casting activity decreased surface runoff, they were not involved in soil detachment, and therefore soil erosion.
Advances in Materials Science and Engineering, 2015
ABSTRACT Electrospun microfibers (MFs) composed of pH and temperature responsive polymers can be ... more ABSTRACT Electrospun microfibers (MFs) composed of pH and temperature responsive polymers can be used for controllable and variable delivery of ibuprofen. First, electrospinning technique was employed to prepare poly(ε-caprolactone) (PCL) and poly(N-isopropylacrylamide-co-methacrylic acid) (pNIPAM-co-MAA) MFs containing ibuprofen. It was found that drug release rates from PCL MFs cannot be significantly varied by either temperature (22-40°C) or pH values (1.7-7.4). In contrast, the ibuprofen (IP) diffusion rates from pNIPAM-co-MAA MFs were very sensitive to changes in both temperature and pH. The IP release from pNIPAM-co-MAA MFs was highly linear and controllable when the temperature was above the lower critical solution temperature (LCST) of pNIPAM-co-MAA (33°C) and the pH was lower than the of carboxylic acids (pH 2). At room temperature, however, the release rate was dramatically increased by nearly ten times compared to that at higher temperature and lower pH. Such a unique and controllable drug delivery system could be naturally envisioned to find many practical applications in biomedical and pharmaceutical sciences such as programmable transdermal drug delivery.
This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil e... more This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil erosion in steep-slope ecosystems in Northern Vietnam. We investigated the effects of Amynthas khami, an anecic species producing above-ground casts of prominent size, on water infiltration and soil detachment along a land-use intensification gradient: a cultivation of cassava (Mahinot esculenta; CAS), a plantation of Bracharia (Bracharia ruzziziensis; BRA), a fallow (FAL), a fallow after a forest of Eucalyptus sp. (EUC) and a plantation of trees (Acacia mangium and Venicia Montana; FOR). Two scales of studies were considered: (i) at the structure scale (cm 2 ), a water runoff simulation was used to differentiate the effects of casts, free biogenic aggregates that previously belong to casts, and free physicogenic aggregates; (ii) at the station levels, 1-m 2 plots were used to determine runoff and soil detachment rates during the rainy season in 2005.
ABSTRACT We present a study of thermoelectric energy harvesting with nano-sized thermopiles (nTE)... more ABSTRACT We present a study of thermoelectric energy harvesting with nano-sized thermopiles (nTE) in a planar 65 nm silicon CMOS process. These devices generated power from a 5C temperature difference at a density comparable to commercially available thermoelectric generators, following a metric used in the research literature [1]. By analyzing a thermoelectric harvesting system, we explore the impact of additional performance metrics such as heat source/sink thermal impedance, available heat flow density, and voltage stacking, providing a more comprehensive set of criteria for evaluating the suitability of harvesting technology.
Background: Differences between urban and rural settings can be seen as a very important example ... more Background: Differences between urban and rural settings can be seen as a very important example of gaps between groups in a population. The aim of this paper is to compare an urban and a rural area regarding child growth during the first two years of life as related to mother's use of antenatal care (ANC), breastfeeding and reported symptoms of illness.
Electrospin Lithium ion battery a b s t r a c t Three types of SnO 2 /TiO 2 composite nanofibers ... more Electrospin Lithium ion battery a b s t r a c t Three types of SnO 2 /TiO 2 composite nanofibers (homogeneous SnO 2 /TiO 2 , heterogeneous SnO 2 /TiO 2 and SnO 2 NPs/TiO 2 ) have been prepared via a facile electrospinning method combined with a sol-gel chemistry, whose electrochemical performance as anode materials in lithium-ion battery was evaluated and compared to that of pure TiO 2 and SnO 2 electrospunnanofibers (NFs). Rutile phase TiO 2 nanofibers demonstrated an extremely stable but relatively low gravimetric specific capacity of ∼80 mAh g −1 when discharged at 100 mA g −1 . In contrast, rutile phase SnO 2 nanofibers showed a much more unstable but higher specific capacity, which dropped from initial 800 to ∼35 mAh g −1 after 50 cycles. The incorporation of structurally unstable SnO 2 into stable TiO 2 matrix can significantly improve both the cycling performance and specific capacity. These composite nanofibers possess a much higher initial gravimetric specific capacity (>500 mAh g −1 ) than rutile phase TiO 2 nanofibers and maintain superior capacity retention to pure SnO 2 NFs. The enhanced cycling stability is attributed to the space confinement provided by the structurally stable TiO 2 , which finding can provide a beneficial guidance for future lithium ion battery electrode development.
Introduction: Community acquired K. pneumoniae pneumonia is still common in Asia and is reportedl... more Introduction: Community acquired K. pneumoniae pneumonia is still common in Asia and is reportedly associated with alcohol use. Oropharyngeal carriage of K. pneumoniae could potentially play a role in the pathogenesis of K. pneumoniae pneumonia. However, little is known regarding K. pneumoniae oropharyngeal carriage rates and risk factors. This population-based cross-sectional study explores the association of a variety of demographic and socioeconomic factors, as well as alcohol consumption with oropharyngeal carriage of K. pneumoniae in Vietnam.
Background The use of antenatal care (ANC) varies between countries and in different settings wit... more Background The use of antenatal care (ANC) varies between countries and in different settings within each country. Most previous studies of ANC in Vietnam have been cross-sectional, and conducted in rural areas before the year 2000. This study aims to compare the pattern and the adequacy of ANC used in rural and urban Vietnam following two cohorts of pregnant women. Methods A comparative study with two cohorts comprising totally 2132 pregnant women were followed in two health and demographic surveillance sites, one rural and one urban in Hanoi province, Vietnam. The women were quarterly interviewed using a structured questionnaire until delivery. The primary information obtained was the number and the content of ANC visits. Results Almost all women reported some use of ANC. The average number of visits was much lower in the rural setting (4.4) than in the urban (7.7). In the rural area, 77.2% of women had at least three visits and 69.1% attended ANC during the first trimester. The corresponding percentages for the urban women were 97.2% and 97.2%. Only 20.3% of the rural women compared to 81.1% of the urban women received all core ANC services. As a result, the adequate use of ANC was 5.2 times in the urban than in the rural setting (78.3% compared to 15.2%). Nearly all women received ultrasound examination during pregnancy with a mean value of 6.0 scans per woman in the urban area and 3.5 in the rural. Most rural women used ANC at commune health centres and private clinics while urban women mainly visited public hospitals. Expenditure related to ANC utilization for the urban women was 7.1 times that for the urban women. Conclusion The women in the rural area attended ANC later, had fewer visits and received much fewer services than urban women. The large disparity in ANC adequacy between the two settings suggests special attention for the ANC programme in rural areas focusing on its content. Revision and enforcement of the national guidelines to improve the behaviour and practice of both users and providers are necessary.
This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil e... more This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil erosion in steep-slope ecosystems in Northern Vietnam. We investigated the effects of Amynthas khami, an anecic species producing above-ground casts of prominent size, on water infiltration and soil detachment along a land-use intensification gradient: a cultivation of cassava (Mahinot esculenta; CAS), a plantation of Bracharia (Bracharia ruzziziensis; BRA), a fallow (FAL), a fallow after a forest of Eucalyptus sp. (EUC) and a plantation of trees (Acacia mangium and Venicia Montana; FOR). Two scales of studies were considered: (i) at the structure scale (cm2), a water runoff simulation was used to differentiate the effects of casts, free biogenic aggregates that previously belong to casts, and free physicogenic aggregates; (ii) at the station levels, 1-m2 plots were used to determine runoff and soil detachment rates during the rainy season in 2005.A. khami was sensitive to land-use management. Earthworm density was low in all the fields (0–1 ind m− 2). The highest densities were found in EUC and FOR and no individual was found in CAS. As a consequence, soil surface in EUC and FOR was covered with casts and free biogenic aggregates (approximately 22 and 8 kg m− 2, respectively). In FAL and BRA, casts covered the soil only sparsely with < 3 kg m− 2. In CAS, soil surface was characterized by free physicogenic aggregates that might be produced by human activity or endogeic earthworms through tillage (approximately 1 kg m− 2). Water runoff simulation clearly showed an enhancement of water infiltration with earthworm casting activity. Water runoff was more decreased with casts (R2 = 0.26) than free biogenic aggregates (R2 = 0.49). Conversely, physicogenic aggregates were not associated with higher water infiltration. Analyses of runoff and soil detachment rates during the rainy season underlined that the more land-use type have aggregates on soil surface and the less important is surface runoff (R2 = 0.922). Conversely, no relation occurred between aggregates and soil detachment rate. While above-ground casting activity decreased surface runoff, they were not involved in soil detachment, and therefore soil erosion.
Advances in Materials Science and Engineering, 2015
ABSTRACT Electrospun microfibers (MFs) composed of pH and temperature responsive polymers can be ... more ABSTRACT Electrospun microfibers (MFs) composed of pH and temperature responsive polymers can be used for controllable and variable delivery of ibuprofen. First, electrospinning technique was employed to prepare poly(ε-caprolactone) (PCL) and poly(N-isopropylacrylamide-co-methacrylic acid) (pNIPAM-co-MAA) MFs containing ibuprofen. It was found that drug release rates from PCL MFs cannot be significantly varied by either temperature (22-40°C) or pH values (1.7-7.4). In contrast, the ibuprofen (IP) diffusion rates from pNIPAM-co-MAA MFs were very sensitive to changes in both temperature and pH. The IP release from pNIPAM-co-MAA MFs was highly linear and controllable when the temperature was above the lower critical solution temperature (LCST) of pNIPAM-co-MAA (33°C) and the pH was lower than the of carboxylic acids (pH 2). At room temperature, however, the release rate was dramatically increased by nearly ten times compared to that at higher temperature and lower pH. Such a unique and controllable drug delivery system could be naturally envisioned to find many practical applications in biomedical and pharmaceutical sciences such as programmable transdermal drug delivery.
This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil e... more This manuscript focuses on the effects of above-ground earthworm casts on water runoff and soil erosion in steep-slope ecosystems in Northern Vietnam. We investigated the effects of Amynthas khami, an anecic species producing above-ground casts of prominent size, on water infiltration and soil detachment along a land-use intensification gradient: a cultivation of cassava (Mahinot esculenta; CAS), a plantation of Bracharia (Bracharia ruzziziensis; BRA), a fallow (FAL), a fallow after a forest of Eucalyptus sp. (EUC) and a plantation of trees (Acacia mangium and Venicia Montana; FOR). Two scales of studies were considered: (i) at the structure scale (cm 2 ), a water runoff simulation was used to differentiate the effects of casts, free biogenic aggregates that previously belong to casts, and free physicogenic aggregates; (ii) at the station levels, 1-m 2 plots were used to determine runoff and soil detachment rates during the rainy season in 2005.
ABSTRACT We present a study of thermoelectric energy harvesting with nano-sized thermopiles (nTE)... more ABSTRACT We present a study of thermoelectric energy harvesting with nano-sized thermopiles (nTE) in a planar 65 nm silicon CMOS process. These devices generated power from a 5C temperature difference at a density comparable to commercially available thermoelectric generators, following a metric used in the research literature [1]. By analyzing a thermoelectric harvesting system, we explore the impact of additional performance metrics such as heat source/sink thermal impedance, available heat flow density, and voltage stacking, providing a more comprehensive set of criteria for evaluating the suitability of harvesting technology.
Background: Differences between urban and rural settings can be seen as a very important example ... more Background: Differences between urban and rural settings can be seen as a very important example of gaps between groups in a population. The aim of this paper is to compare an urban and a rural area regarding child growth during the first two years of life as related to mother's use of antenatal care (ANC), breastfeeding and reported symptoms of illness.
Electrospin Lithium ion battery a b s t r a c t Three types of SnO 2 /TiO 2 composite nanofibers ... more Electrospin Lithium ion battery a b s t r a c t Three types of SnO 2 /TiO 2 composite nanofibers (homogeneous SnO 2 /TiO 2 , heterogeneous SnO 2 /TiO 2 and SnO 2 NPs/TiO 2 ) have been prepared via a facile electrospinning method combined with a sol-gel chemistry, whose electrochemical performance as anode materials in lithium-ion battery was evaluated and compared to that of pure TiO 2 and SnO 2 electrospunnanofibers (NFs). Rutile phase TiO 2 nanofibers demonstrated an extremely stable but relatively low gravimetric specific capacity of ∼80 mAh g −1 when discharged at 100 mA g −1 . In contrast, rutile phase SnO 2 nanofibers showed a much more unstable but higher specific capacity, which dropped from initial 800 to ∼35 mAh g −1 after 50 cycles. The incorporation of structurally unstable SnO 2 into stable TiO 2 matrix can significantly improve both the cycling performance and specific capacity. These composite nanofibers possess a much higher initial gravimetric specific capacity (>500 mAh g −1 ) than rutile phase TiO 2 nanofibers and maintain superior capacity retention to pure SnO 2 NFs. The enhanced cycling stability is attributed to the space confinement provided by the structurally stable TiO 2 , which finding can provide a beneficial guidance for future lithium ion battery electrode development.
Introduction: Community acquired K. pneumoniae pneumonia is still common in Asia and is reportedl... more Introduction: Community acquired K. pneumoniae pneumonia is still common in Asia and is reportedly associated with alcohol use. Oropharyngeal carriage of K. pneumoniae could potentially play a role in the pathogenesis of K. pneumoniae pneumonia. However, little is known regarding K. pneumoniae oropharyngeal carriage rates and risk factors. This population-based cross-sectional study explores the association of a variety of demographic and socioeconomic factors, as well as alcohol consumption with oropharyngeal carriage of K. pneumoniae in Vietnam.
Uploads
Papers by Toan Tran