Papers by Kien Luan Nguyen
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2021
We present a framework to quantify the radiation from tropical cyclones (TCs) in shortwave (SW, w... more We present a framework to quantify the radiation from tropical cyclones (TCs) in shortwave (SW, wavelength smaller than 3 micron) and longwave (LW, wavelength larger than 3 micron) portions of the electromagnetic spectrum. The framework includes two stages: segmentation of TC clouds and calculation of the radiation effects attributable to TC clouds. The segmentation task is accomplished by an algorithm which takes a time series of brightness temperature images of TCs and uses image processing techniques to acquire segmentation for each image in a semisupervised manner. The radiation is calculated by combining the segmentation results with the cloud and earth's radiant energy system dataset via a coordinate-matching scheme due to their difference in resolution. The framework was implemented to analyze the net contribution of TCs to the upwelling radiation in 2016 and in summer months between 2015 and 2019 at regional and global scales. Results show that both the magnitude and the variability of radiation contribution by TCs are of an order of magnitude that could have a significant effect on the overall earth's energy balance.
Nutrients, 2020
Child overweight or obesity is increasing in most countries, including Vietnam. We sought to eluc... more Child overweight or obesity is increasing in most countries, including Vietnam. We sought to elucidate the drivers of child overweight or obesity in Vietnam and understand how they vary geographically. We compiled nationally representative cross-sectional data from the Vietnam Nutrition Surveillance Survey collected annually between 2012–2015 and household income data from the General Statistics Office. We used a quasi-Poisson log link function to calculate relative risks (RRs) of under-five child overweight or obesity for 13 variables and stratified analyses by child age (<2 y and 2–5 y) and region. Additional analysis included log-log linear regression to assess the relationship between average provincial monthly per capita income and child overweight or obesity. The strongest associations with child overweight or obesity included birthweight >4000 g (RR: 1.66; 95% confidence interval (CI): 1.48, 1.86), maternal body mass index (BMI) ≥27.5 compared with BMI <23 (RR: 1.62;...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1998
Acute stressor exposure alters immune function. Rats exposed to inescapable tail shock stress (IS... more Acute stressor exposure alters immune function. Rats exposed to inescapable tail shock stress (IS) generate less antibody to a benign, antigenic protein, keyhole limpet hemocyanin (KLH). The following studies examined the effect of IS on peritoneal cavity, spleen, and mesenteric lymph node cell number, interferon-γ (IFN-γ) production, and nitrite production. Rats were injected intraperitoneally with KLH (200 μg) or saline immediately before IS exposure and killed 0, 48, and 96 h after IS termination. KLH immunization resulted in elevated cell numbers and IFN-γ levels 2–4 days later in nonstressed control rats. In contrast, rats exposed to IS failed to increase cell number and IFN-γ levels in response to KLH. The T cell subpopulations affected were CD4 T cells, specifically the Th1-like subset. In addition, in rats exposed to IS + KLH, nitrite production was potentiated 2–4 days after stressor termination. IS had little effect on these measures in saline-injected rats. These data sup...
The Singapore Economic Review, 2019
This paper examines ownership-related wage differentials for four types of workers employed by me... more This paper examines ownership-related wage differentials for four types of workers employed by medium–large (20 or more employees) wholly foreign multinational enterprises (WFs), joint-venture multinationals (JVs), state-owned enterprises (SOEs) and domestic private firms in Vietnamese manufacturing in 2009. When all sample firms were combined, unconditional JV-private and WF-private wage differentials were 106–124% for managers, 78–87% for professionals and technicians, 56–68% for clerical and support workers and 22–48% for production workers. Correspondingly, conditional wage differentials which account for influences of worker education and sex, in addition to firm capital intensity and size, were smaller and usually significant: 72–78% for managers, 32–36% for professionals and technicians, 23–28% for clerical and support workers and 15–16% for production workers. SOE-private differentials were all much smaller. There was substantial variation at the industry level, but conditio...
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2000
The vagus nerve appears to play a role in communicating cytokine signals to the central nervous s... more The vagus nerve appears to play a role in communicating cytokine signals to the central nervous system, but the exact extent of its involvement in cytokine-to-brain communication remains controversial. Recently, subdiaphragmatic vagotomy was shown to increase bacterial translocation across the gut barrier and thus may cause endotoxin tolerance. The current experiment tested whether or not vagotomized animals have similar systemic responses to endotoxin challenge as do sham-operated animals. Subdiaphragmatically vagotomized and sham-operated animals were injected intraperitoneally with one of three doses (10, 50, 100 μg/kg) of lipopolysaccharide (LPS) or vehicle, and blood samples were taken at 15, 30, 60, 90, and 120 min after the injection. The intraperitoneal injection of LPS increased circulating LPS levels at all time points examined. In addition, all three doses of LPS significantly increased serum interleukin (IL)-1β, IL-6, and corticosterone in both control and vagotomized ra...
The Journal of Neuroscience, 1999
Intraperitoneal administration of the cytokine interleukin-1 (IL-1) induces brain-mediated sick... more Intraperitoneal administration of the cytokine interleukin-1 (IL-1) induces brain-mediated sickness symptoms that can be blocked by subdiaphragmatic vagotomy. Intraperitoneal IL-1 also induces expression of the activation marker c-fos in vagal primary afferent neurons, suggesting that IL-1 is a key component of vagally mediated immune-to-brain communication. The cellular sources of IL-1 activating the vagus are unknown, but may reside in either blood or in the vagus nerve itself. We assayed IL-1 protein after intraperitoneal endotoxin [lipopolysaccharide (LPS)] injection in abdominal vagus nerve, using both an ELISA and immunohistochemistry, and in blood plasma using ELISA. IL-1 levels in abdominal vagus nerve increased by 45 min after LPS administration and were robust by 60 min. Plasma IL-1 levels increased by 60 min, whereas little IL-1 was detected in cervical vagus or sciatic nerve. IL-1immunoreactivity (IR) was expressed in dendritic cells and macrophages within connective tissues associated with the abdominal vagus by 45 min after intraperitoneal LPS injection. By 60 min, some immune cells located within the nerve and vagal paraganglia also expressed IL-1-IR. Thus, intraperitoneal LPS induced IL-1 protein within the vagus in a time-frame consistent with signaling of immune activation. These results suggest a novel mechanism by which IL-1 may serve as a molecular link between the immune system and vagus nerve, and thus the CNS.
The Journal of Neuroscience, 2001
Perispinal (intrathecal) injection of the human immunodeficiency virus-1 (HIV-1) envelope glycopr... more Perispinal (intrathecal) injection of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein gp120 creates exaggerated pain states. Decreases in response thresholds to both heat stimuli (thermal hyperalgesia) and light tactile stimuli (mechanical allodynia) are rapidly induced after gp120 administration. gp120 is the portion of HIV-1 that binds to and activates microglia and astrocytes. These glial cells have been proposed to be key mediators of gp120-induced hyperalgesia and allodynia because these pain changes are blocked by drugs thought to affect glial function preferentially. The aim of the present series of studies was to determine whether gp120induced pain changes involve proinflammatory cytokines [interleukin-1 (IL-1) and tumor necrosis factor-␣ (TNF-␣)], substances released from activated glia. IL-1 and TNF antagonists each prevented gp120-induced pain changes. Intrathecal gp120 produced time-dependent, site-specific increases in TNF and IL-1 protein release into lumbosacral CSF; parallel cytokine increases in lumbar dorsal spinal cord were also observed. Intrathecal administration of fluorocitrate (a glial metabolic inhibitor), TNF antagonist, and IL-1 antagonist each blocked gp120-induced increases in spinal IL-1 protein. These results support the concept that activated glia in dorsal spinal cord can create exaggerated pain states via the release of proinflammatory cytokines.
The Journal of Neuroscience, 1998
Peripheral immune stimulation such as that provided by lipopolysaccharide (LPS) has been reported... more Peripheral immune stimulation such as that provided by lipopolysaccharide (LPS) has been reported to increase brain levels of IL-1 mRNA, immunoreactivity, and bioactivity. Stressors produce many of the same neural and endocrine responses as those that follow LPS, but the impact of stressors on brain interleukin-1 (IL-1) has not been systematically explored. An ELISA designed to detect IL-1 was used to measure levels of IL-1 protein in rat brain. Brain IL-1 was explored after exposure to inescapable shock (IS; 100 1.6 mA tail shocks for 5 sec each) and LPS (1 mg/kg) as a positive control. Rats were killed either immediately or 2, 7, 24, or 48 hr after IS. Brains were dissected into hypothalamus, hippocampus, cerebellum, posterior cortex, and nucleus tractus solitarius regions. LPS produced widespread increases in brain IL-1, but IS did not. Adrenal glucocorticoids are known to suppress IL-1 production in both the periphery and brain. Thus, it was possible that the stressor did provide stimulus input to the brain IL-1 system(s), but that the production of IL-1 protein was suppressed by the rapid and prolonged high levels of glucocorticoids produced by IS. To test this possibility rats were adrenalectomized or given sham surgery, with half of the adrenalectomized rats receiving corticosterone replacement to maintain basal corticosterone levels. IS produced large increases in brain IL-1 protein in the adrenalectomized subjects 2 hr after stress, whether basal corticosterone levels had been maintained. Thus elimination of the stress-induced rise in corticosterone unmasked a robust and widespread increase in brain IL-1.
Global Economic Review, 2017
The views expressed in this publication are those of the author(s) and do not necessarily reflect... more The views expressed in this publication are those of the author(s) and do not necessarily reflect those of the Institute. No part of this article may be used reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in articles and reviews. For information, please write to the Institute.
A 65-nm CMOS high-efficiency PWM/PFM Buck Converter with Bypass mode for Transceiver applications
2016 International Conference on IC Design and Technology (ICICDT), 2016
This paper presents the design of high efficiency PWM/PFM Buck Converter with Bypass mode for Tra... more This paper presents the design of high efficiency PWM/PFM Buck Converter with Bypass mode for Transceiver applications. In this design, when the input voltage falls below 1.9V, the converter automatically enters Bypass mode. When input voltage rises upper 2.1V, the converter operates in PWM mode or PFM mode depending on load current. The conversion efficiency is over 85% with load current range from 2mA to 400mA.
Design and Management of Water Circuits of a Closed Integrated Unbleached Kraft Pulp Mill
Modern unbleached integrated kraft pulp mills have low water consumption compared with traditiona... more Modern unbleached integrated kraft pulp mills have low water consumption compared with traditional pulp and paper mills. Modern pulp mills can be equipped with new technologies and well-designed process integration to reduce the fresh water make-up and effluent load down to insignificant levels. In general, the use of evaporation loss is essential for maintaining the water balance. br> If the stripped condensate is adequately polished so that it can be used to replace the fresh water make-up to the paper machine the fresh water make-up can be reduced to less than 1.7 m3/t. A reduction of fresh water make-up will result in a lower evaporation loss, subsequently reducing the total energy consumption of the mill.
Fibre Charge of Unbleached and Bleached Pinus radiata Kraft Pulps Subjected to Different Degrees of Refining
Three different techniques - potentiometric titrations, conductometric titrations (with NaOH and ... more Three different techniques - potentiometric titrations, conductometric titrations (with NaOH and NaHCO3 separately) and polyelectrolyte titrations were used to determine the fibre charge of unbleached and bleached pinus radiata kraft pulps that were subjected to different degrees of refining. The conductometric titrations gave slightly higher values than the potentiometric titrations. The surface charge as determined by titration with poly-DADMAC was highly dependent on the degree of refining but the total fibre charge as given by potentiometric titration and conductometric titration with NaOH remained constant after refining.
BS-3-37 Improving Flow Capacity of Multi-Hop MAC Protocol for Sensor Networks(BS-3. Management and Control Technologies for Innovative Networks)
電子情報通信学会総合大会講演論文集, Mar 6, 2012
Identification of FTIR Characteristic Bands of Softwood Kraft Lignin in Alkali Solutions by FT-IR Spectroscopy
Lignin was precipitated by acidification of black liquor (KBL) obtained from low-solid kraft pulp... more Lignin was precipitated by acidification of black liquor (KBL) obtained from low-solid kraft pulping of pinus radiata. The precipitated lignin was thoroughly washed and then re-dissolved in alkali solutions for infra-red studies. Mid-infrared spectra were obtained for the solutions, using a Fourier Transform Infrared (FT-IR) spectrometer equipped with a Zinc-Selenide crystal Horizontal Attenuated Total Reflectance (HATR) cell. It was found that the absorption of lignin was clearly observed in the 1600-1000 cm-1 region and the absorption intensity of these bands sensitively changes with the lignin concentration. Bands that are associated with the aromatic rings (1495 and 1420 cm-1), asymmetric bending of methyl groups (1470 cm-1) ring breathing with C-O stretching (1287, 1265, 1238 and 1132 cm-1) and aromatic C-H in-plane deformation (1032 cm-1) are clearly shown on the obtained spectra.
BS-7-55 Virtual-AP Extended Multihop Access Networks
電子情報通信学会ソサイエティ大会講演論文集, Sep 3, 2013
Diffusion washing of unbleached kraft pulps of different eucalypt species
Appita Journal, 1997
Diffusion washing for unbleached kraft pulps from eucalypt wood (Eucalyptus globulus, E.grandis a... more Diffusion washing for unbleached kraft pulps from eucalypt wood (Eucalyptus globulus, E.grandis and E.regnans) was studied. Lignin removal during washing was characterized by UV absorbance measurement at wavelength 205 nm. The pulps were washed from an initial Kappa No. in the range 13.0/6.2. The diffusion washing was highly temperature dependent. UV absorption and COD measurements of the wash filtrate were strongly correlated. The linear relationship between these two parameters indicated that washable lignin was the main contribution to the COD of the wash liquor Correlations between UV absorption and conductivity were not linear but depended highly on temperature and fibre type. Washing curves (UV absorbance versus time) are different for each type of pulp but the normalized washing curves showed similar trends in the washing of E.globulus and E.grandis. The rate of washing of E.regnans was slower.
Distribution of Ca2+ in Slurries of a High-yield Kraft Pulp
The distribution coefficient of Ca2+ in slurries of a high-yield kraft pulp was determined and co... more The distribution coefficient of Ca2+ in slurries of a high-yield kraft pulp was determined and compared with predictions obtained from the model based on Donnan theory. The model, which takes into account the presence of both carboxylic and phenolic groups, was established. This model provided a good prediction of the distribution coefficients in the unbleached pulp slurries over the pH range of 2 to 10. When pH exceeded 10 this model underestimated the distribution coefficient due probably to the presence of at least another ionisable group with a high pKa.
Kinetics of Green Liquor Oxidation
In an atmospheric well-mixed reactor the rate of green liquor oxidation is highly dependent on th... more In an atmospheric well-mixed reactor the rate of green liquor oxidation is highly dependent on the agitator speed, temperature and oxygen superficial velocity. Under non-flooding condition the reaction rate constant is strongly correlated to the power/volume ratio and oxygen superficial velocity. The rate of oxidation is significantly reduced when the temperature and superficial oxygen velocity are excessively high.
The Induction of Valine Dehydrocenase Activity from Streptomyces by L-Valine is Not Repressed by Ammonium
Biotechnol Lett, 1995
The classical store-and-forward routing has and will continue to be the most important routing ar... more The classical store-and-forward routing has and will continue to be the most important routing architecture in many modern packet-switched communication networks. In a packet-switched network, data is sent in the form of discrete packets that traverse hop-by-hop from a source to a destination. At each intermediate hop, the router stores and examines the packets it receives then forwards them
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Papers by Kien Luan Nguyen