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Papers by le quoc son

Materiae Vegetabiles, 1957

Boletim da Sociedade Paranaense de Matemática, 2013

In this paper we consider a mixed boundary value problem for biharmonic equation of the Airy stre... more In this paper we consider a mixed boundary value problem for biharmonic equation of the Airy stress function which models a crack problem of a solid elastic plate. An iterative method for reducing the problem to a sequence of mixed problems for Poisson equations is proposed and investigated. The convergence of the method is established theoretically and illustrated on many numerical experiments.

The use of conventional maximum likelihood estimates hinders the performance of existing phrase-b... more The use of conventional maximum likelihood estimates hinders the performance of existing phrase-based translation models. For lack of sufficient training data, most models only consider a small amount of context. As a partial remedy, we explore here several continuous space translation models, where translation probabilities are estimated using a continuous representation of translation units in lieu of standard discrete representations. In order to handle a large set of translation units, these representations and the associated estimates are jointly computed using a multi-layer neural network with a SOUL architecture. In small scale and large scale English to French experiments, we show that the resulting models can effectively be trained and used on top of a n-gram translation system, delivering significant improvements in performance.

Abstracts of the Annual Meetings, Japanese Society of Soil Science and Plant Nutrition, 1998

In spite of their well known limitations, most notably their use of very local contexts, n-gram l... more In spite of their well known limitations, most notably their use of very local contexts, n-gram language models remain an essential component of many Natural Language Processing applications, such as Automatic Speech Recognition or Statistical Machine Translation. This paper investigates the potential of language models using larger context windows comprising up to the 9 previous words. This study is made possible by the development of several novel Neural Network Language Model architectures, which can easily fare with such large context windows. We experimentally observed that extending the context size yields clear gains in terms of perplexity and that the n-gram assumption is statistically reasonable as long as n is sufficiently high, and that efforts should be focused on improving the estimation procedures for such large models.

VTC Spring 2008 - IEEE Vehicular Technology Conference, 2008

ABSTRACT Multi-carrier OFDM-CDMA has a range of advantages that make it ideal for high data rate ... more ABSTRACT Multi-carrier OFDM-CDMA has a range of advantages that make it ideal for high data rate wireless access system. In this paper, a cross-layer multi-service random access and channel assignment approach is proposed for the uplink communication of the mm wavelength multi-carrier OFDM-CDMA BWA system. The OFDM-CDMA solution and the iterative interference cancellation and detection are applied at the system's physical layer to support multi-user multi-service capabilities and to improve the robustness against the flat and frequency selective fading. The proposed scheme grants the uplink random access connections and allocates the radio resources to the active multiservice subscriber stations by using the cooperation between base station and subscriber stations, as well as the diversities in spreading codes, subcarriers, time in OFDM symbols, and time division multiplex. A MAC protocol and its connection and channel assignment procedures are described. Numeric simulations of the uplink BWA system with the proposed random access and channel assignment scheme are carried out to evaluate the system's performance.

The 8th International Conference on Communication Systems, 2002. ICCS 2002.

With the current development of mobile devices, short range wireless communications have become m... more With the current development of mobile devices, short range wireless communications have become more and more popular, and many researches on short range wireless communications, such as Bluetooth, have gained special interests, in industry as well as in academy. This paper analyzes capacity allocation issues in Bluetooth network as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. The hybrid distributed capacity allocation scheme is proposed as an approximated solution of the formulated problem that satisfies quality of service requirements and constraints in Bluetooth network, such as limited capacity, decentralized, frequent changes of topology and of capacities assigned to nodes in the network. The simulation shows that the performance of Bluetooth could be improved by applying the hybrid distributed iterative capacity allocation scheme.

Herbicides and Environment, 2011

Communications in Physics, 2007

We have investigated the effects of temperature on the magnetic easy axis reorientation (EARs) in... more We have investigated the effects of temperature on the magnetic easy axis reorientation (EARs) in polycrystalline ferromagnetic (FM) nano-scale thin films, i.e. (001)-oriented cubic films such as Fe, Ni, CFO and (0001)oriented hexagonal films such as Co, grown on ferroelectric (FE) substrates, for example PZT, BTO substrates. The model of FM/FE bilayered heterostructures has been applied to study the total free energy of the FM films. By minimizing this energy, we have shown that temperature has a significant effect on a critical electric field induced magnetic reorientation.

Journal of Oleo Science, 2014

kine modulatory 5 , antioxidant and antibacterial 6 , toxicity and insecticidal 7, 8 , anti-infla... more kine modulatory 5 , antioxidant and antibacterial 6 , toxicity and insecticidal 7, 8 , anti-inflammatory 9 , xanthine oxidase inhibitor 10 and cytotoxicity 11. The volatile compounds are usually mono-and sesquiterpene compounds, though E-cinnamaldehyde featured prominently as the major compound of some species which included C. osmophloeum 5 , C. paciflorum 12 , C. pubescens 6 , C. aromaticum 8 and C. zeylanicum 13. On the other hand, compounds such as linalool in C. camphora var. linaloolifera 14 ; safrole and benzyl benzoate in C. parthenoxylon 15 ; 2-methylene-3-buten-1-yl-benzoate in Cinnamomum sp 16 ; eugenol and 1, 8-cineole in C. albiflorum 17 ; spathulenol, caryophyllene oxide and β-caryophyllene in C. sericans; ρ-cymene, limonene and α-phellandrene in C. durifolium; bicyclogermacrene, β-caryophyllene in C. magnificum; as well as β-caryophyllene, caryophyllene oxide and spathulenol in C. iners 2 were identified in higher proportions in these previously studied species.

Pediatric Surgery International, 2015

Purpose Severe chordee with hypospadias may require repair by ventral corporoplasty with a free g... more Purpose Severe chordee with hypospadias may require repair by ventral corporoplasty with a free graft before urethroplasty. We report an 11 year experience with onestage and two-stage hypospadias repair using dermal grafts. Materials and methods From 12/1997 to 12/2008, 47 hypospadias with severe chordee were repaired using a ventral dermal graft to correct the chordee. Forty cases were repaired in two stages; the remaining seven patients had adequate preputial skin and were repaired in one stage. In 28 cases the neourethra was covered with both tunica vaginalis and penile dartos flap while 12 were covered only with penile dartos flap. Patients ranged from 12 to 152 months of age. Follow-up ranged from 6 months to 4 years. Results 28 patients with both tunica vaginalis and dartos flap had 7 urethral fistulas and 2 developed meatal stenosis. 12 patients with only penile dartos flap had 3 fistulas and 2 had meatal regression. The seven patients who underwent a one-stage repair had good results with a straight penis and no evidence of urethral fistula or urethral stenosis. Conclusions Dermal graft can be performed in one or two stage hypospadias repair. Complication rates are similar to other standard repairs for proximal hypospadias.

Journal of Atherosclerosis and Thrombosis, 2011

The Vietnamese develop type 2 diabetes (T2D) and metabolic syndrome (MS) at a lower BMI than othe... more The Vietnamese develop type 2 diabetes (T2D) and metabolic syndrome (MS) at a lower BMI than other ethnicities. Thus, biomarkers that identify subjects at an increased risk of T2D independently of obesity are being sought. Recent studies show that circulating NO metabolites (NOx) are increased in T2D. We investigated whether plasma NOx levels predict insulin resistance and glucose intolerance before the development of T2D, independently of obesity. Methods: The current study was derived from a population-based study in HCMC, Vietnam, which was designed to investigate the prevalence of MS and T2D in a population aged 30-69 years. Four hundred and twenty-two subjects were recruited from the study and were stratified into 4 age-and gender-matched groups according to a glucose tolerance test {normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and T2D}. Results: Plasma NOx concentrations were significantly increased in T2D but not in IFG or IGT compared with NGT. Multiregression analysis showed that plasma NOx levels were inversely correlated with BMI in T2D whereas no association was found between plasma NOx levels and BMI in non-diabetic subjects. Moreover, there was no correlation between plasma NOx levels and homeostasis model assessment-insulin resistance (HOMA-IR) in both diabetic and non-diabetic subjects. Conclusion: Plasma NOx levels did not predict glucose intolerance or insulin resistance before the development of T2D and the increase in plasma NOx levels in T2D was not caused by adiposity. Thus, plasma NOx is not a useful marker for the prediction of high-risk subjects for T2D among Vietnamese.

Environmental science and pollution research international, Jan 17, 2014

The Bien Hoa airbase (south of Vietnam) is known as one of the Agent Orange hotspots which have b... more The Bien Hoa airbase (south of Vietnam) is known as one of the Agent Orange hotspots which have been seriously contaminated by Agent Orange/dioxin during the Vietnam War. Hundreds of samples including soil, sediment and fish were collected at the Bien Hoa Agent Orange hotspot for assessment of the environmental contamination caused by dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The toxicity equivalency quotient (TEQ) concentration of PCDD/Fs in soil and sediment varied from 7.6 to 962,000 and 17 to 4860 pg/g dry wt, respectively, implying very high contamination of PCDD/Fs in several areas. PCDD/F levels in fish ranged between 1.8 and 288 pg/g TEQ wet wt and was generally higher than advisory guidelines for food consumption. 2,3,7,8-Tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) contributed 66-99 % of TEQ for most of the samples, suggesting 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) from Agent Orange as the major source of the contamination. The vertical trans...

Urology, 2009

To present the diagnostic results of contrast vaginography to detect a vaginal ectopic ureter, in... more To present the diagnostic results of contrast vaginography to detect a vaginal ectopic ureter, in addition to investigation with ultrasonography, intravenous urography, and technetium-99m-dimercaptosuccinic acid renal scan. A single ectopic ureter is a rare anomaly. Eighteen girls with a single ectopic ureter were treated at the Children's Hospital No. 1 from 1995 to August 2008. The diagnostic studies included ultrasonography, intravenous urography, renal scans, and, finally, vaginography with contrast if the renal scans could not detect the poorly functioning kidneys. Intravenous urography showed a poorly functioning kidney in 1 patient. Another 10 poorly functioning kidneys were revealed by technetium-99m-dimercaptosuccinic acid renal scan, but 7 kidneys were not identifiable using contrast, ultrasonography, or radionuclide. Of these 7 patients, 6 vaginal ectopic ureters were detected using contrast vaginography. All 18 dysplastic kidneys were surgically removed. The results of the study have demonstrated the satisfactory diagnostic value of vaginography as an imaging technique to detect the dysplastic kidney draining by a single ectopic ureter.

Toxicological & Environmental Chemistry, 2011

Human exposure to polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF), especially 2,3,... more Human exposure to polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF), especially 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD), was investigated in Vietnam since initial severe adverse health effects were reported in the late 1970s. The purpose of this study was to determine the effects of dioxin exposure on steroid hormones of primiparae in an Agent Orange/dioxin hot-spot and a non-exposed area in Vietnam. Sixteen primiparae (8 at each site), all of whom were aged between 20 and 30 years with infants aged between 4 and 16 weeks, agreed to participate in this study. The mean dioxin levels in breast milk of primiparae from the hot-spot area, in terms of PCDD, PCDF, and PCDD þ PCDF toxic equivalents (TEQ), were significantly higher than those for the non-exposed area. PCDD TEQ, PCDF TEQ, and PCDD þ PCDF TEQ levels showed a significant correlation with dehydroepiandrosterone (DHEA), androstenedione (A-dione), and estradiol (E2) in the saliva of primiparae in a combination of hot-spot and non-exposed areas in Vietnam. The dose-response curve between salivary E2 or A-dione levels and dioxin levels was U-shaped in humans. This study provides an overview of studies regarding dioxin hot-spots and effects on human health and steroid hormone levels in particular, with a focus on the toxicity attributed to dioxins and furans. Furthermore, causal evidence regarding the effects of dioxins on endocrine disruption in humans is provided.

The International Journal of Biochemistry & Cell Biology, 2013

Dicarbonyl/l-xylulose reductase (DCXR) is a highly conserved and phylogenetically widespread enzy... more Dicarbonyl/l-xylulose reductase (DCXR) is a highly conserved and phylogenetically widespread enzyme converting l-xylulose into xylitol. It also reduces highly reactive ␣-dicarbonyl compounds, thus performing a dual role in carbohydrate metabolism and detoxification. Enzymatic properties of DCXR from yeast, fungi and mammalian tissue extracts are extensively studied. Deficiency of the DCXR gene causes a human clinical condition called pentosuria and low DCXR activity is implicated in age-related diseases including cancers, diabetes, and human male infertility. While mice provide a model to study clinical condition of these diseases, it is necessary to adopt a physiologically tractable model in which genetic manipulations can be readily achieved to allow the fast genetic analysis of an enzyme with multiple biological roles. Caenorhabditis elegans has been successfully utilized as a model to study DCXR. Here, we discuss the biochemical properties and significance of DCXR activity in various human diseases, and the utility of C. elegans as a research platform to investigate the molecular and cellular mechanism of the DCXR biology.

Materiae Vegetabiles, 1957

Boletim da Sociedade Paranaense de Matemática, 2013

In this paper we consider a mixed boundary value problem for biharmonic equation of the Airy stre... more In this paper we consider a mixed boundary value problem for biharmonic equation of the Airy stress function which models a crack problem of a solid elastic plate. An iterative method for reducing the problem to a sequence of mixed problems for Poisson equations is proposed and investigated. The convergence of the method is established theoretically and illustrated on many numerical experiments.

The use of conventional maximum likelihood estimates hinders the performance of existing phrase-b... more The use of conventional maximum likelihood estimates hinders the performance of existing phrase-based translation models. For lack of sufficient training data, most models only consider a small amount of context. As a partial remedy, we explore here several continuous space translation models, where translation probabilities are estimated using a continuous representation of translation units in lieu of standard discrete representations. In order to handle a large set of translation units, these representations and the associated estimates are jointly computed using a multi-layer neural network with a SOUL architecture. In small scale and large scale English to French experiments, we show that the resulting models can effectively be trained and used on top of a n-gram translation system, delivering significant improvements in performance.

Abstracts of the Annual Meetings, Japanese Society of Soil Science and Plant Nutrition, 1998

In spite of their well known limitations, most notably their use of very local contexts, n-gram l... more In spite of their well known limitations, most notably their use of very local contexts, n-gram language models remain an essential component of many Natural Language Processing applications, such as Automatic Speech Recognition or Statistical Machine Translation. This paper investigates the potential of language models using larger context windows comprising up to the 9 previous words. This study is made possible by the development of several novel Neural Network Language Model architectures, which can easily fare with such large context windows. We experimentally observed that extending the context size yields clear gains in terms of perplexity and that the n-gram assumption is statistically reasonable as long as n is sufficiently high, and that efforts should be focused on improving the estimation procedures for such large models.

VTC Spring 2008 - IEEE Vehicular Technology Conference, 2008

ABSTRACT Multi-carrier OFDM-CDMA has a range of advantages that make it ideal for high data rate ... more ABSTRACT Multi-carrier OFDM-CDMA has a range of advantages that make it ideal for high data rate wireless access system. In this paper, a cross-layer multi-service random access and channel assignment approach is proposed for the uplink communication of the mm wavelength multi-carrier OFDM-CDMA BWA system. The OFDM-CDMA solution and the iterative interference cancellation and detection are applied at the system's physical layer to support multi-user multi-service capabilities and to improve the robustness against the flat and frequency selective fading. The proposed scheme grants the uplink random access connections and allocates the radio resources to the active multiservice subscriber stations by using the cooperation between base station and subscriber stations, as well as the diversities in spreading codes, subcarriers, time in OFDM symbols, and time division multiplex. A MAC protocol and its connection and channel assignment procedures are described. Numeric simulations of the uplink BWA system with the proposed random access and channel assignment scheme are carried out to evaluate the system's performance.

The 8th International Conference on Communication Systems, 2002. ICCS 2002.

With the current development of mobile devices, short range wireless communications have become m... more With the current development of mobile devices, short range wireless communications have become more and more popular, and many researches on short range wireless communications, such as Bluetooth, have gained special interests, in industry as well as in academy. This paper analyzes capacity allocation issues in Bluetooth network as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. The hybrid distributed capacity allocation scheme is proposed as an approximated solution of the formulated problem that satisfies quality of service requirements and constraints in Bluetooth network, such as limited capacity, decentralized, frequent changes of topology and of capacities assigned to nodes in the network. The simulation shows that the performance of Bluetooth could be improved by applying the hybrid distributed iterative capacity allocation scheme.

Herbicides and Environment, 2011

Communications in Physics, 2007

We have investigated the effects of temperature on the magnetic easy axis reorientation (EARs) in... more We have investigated the effects of temperature on the magnetic easy axis reorientation (EARs) in polycrystalline ferromagnetic (FM) nano-scale thin films, i.e. (001)-oriented cubic films such as Fe, Ni, CFO and (0001)oriented hexagonal films such as Co, grown on ferroelectric (FE) substrates, for example PZT, BTO substrates. The model of FM/FE bilayered heterostructures has been applied to study the total free energy of the FM films. By minimizing this energy, we have shown that temperature has a significant effect on a critical electric field induced magnetic reorientation.

Journal of Oleo Science, 2014

kine modulatory 5 , antioxidant and antibacterial 6 , toxicity and insecticidal 7, 8 , anti-infla... more kine modulatory 5 , antioxidant and antibacterial 6 , toxicity and insecticidal 7, 8 , anti-inflammatory 9 , xanthine oxidase inhibitor 10 and cytotoxicity 11. The volatile compounds are usually mono-and sesquiterpene compounds, though E-cinnamaldehyde featured prominently as the major compound of some species which included C. osmophloeum 5 , C. paciflorum 12 , C. pubescens 6 , C. aromaticum 8 and C. zeylanicum 13. On the other hand, compounds such as linalool in C. camphora var. linaloolifera 14 ; safrole and benzyl benzoate in C. parthenoxylon 15 ; 2-methylene-3-buten-1-yl-benzoate in Cinnamomum sp 16 ; eugenol and 1, 8-cineole in C. albiflorum 17 ; spathulenol, caryophyllene oxide and β-caryophyllene in C. sericans; ρ-cymene, limonene and α-phellandrene in C. durifolium; bicyclogermacrene, β-caryophyllene in C. magnificum; as well as β-caryophyllene, caryophyllene oxide and spathulenol in C. iners 2 were identified in higher proportions in these previously studied species.

Pediatric Surgery International, 2015

Purpose Severe chordee with hypospadias may require repair by ventral corporoplasty with a free g... more Purpose Severe chordee with hypospadias may require repair by ventral corporoplasty with a free graft before urethroplasty. We report an 11 year experience with onestage and two-stage hypospadias repair using dermal grafts. Materials and methods From 12/1997 to 12/2008, 47 hypospadias with severe chordee were repaired using a ventral dermal graft to correct the chordee. Forty cases were repaired in two stages; the remaining seven patients had adequate preputial skin and were repaired in one stage. In 28 cases the neourethra was covered with both tunica vaginalis and penile dartos flap while 12 were covered only with penile dartos flap. Patients ranged from 12 to 152 months of age. Follow-up ranged from 6 months to 4 years. Results 28 patients with both tunica vaginalis and dartos flap had 7 urethral fistulas and 2 developed meatal stenosis. 12 patients with only penile dartos flap had 3 fistulas and 2 had meatal regression. The seven patients who underwent a one-stage repair had good results with a straight penis and no evidence of urethral fistula or urethral stenosis. Conclusions Dermal graft can be performed in one or two stage hypospadias repair. Complication rates are similar to other standard repairs for proximal hypospadias.

Journal of Atherosclerosis and Thrombosis, 2011

The Vietnamese develop type 2 diabetes (T2D) and metabolic syndrome (MS) at a lower BMI than othe... more The Vietnamese develop type 2 diabetes (T2D) and metabolic syndrome (MS) at a lower BMI than other ethnicities. Thus, biomarkers that identify subjects at an increased risk of T2D independently of obesity are being sought. Recent studies show that circulating NO metabolites (NOx) are increased in T2D. We investigated whether plasma NOx levels predict insulin resistance and glucose intolerance before the development of T2D, independently of obesity. Methods: The current study was derived from a population-based study in HCMC, Vietnam, which was designed to investigate the prevalence of MS and T2D in a population aged 30-69 years. Four hundred and twenty-two subjects were recruited from the study and were stratified into 4 age-and gender-matched groups according to a glucose tolerance test {normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and T2D}. Results: Plasma NOx concentrations were significantly increased in T2D but not in IFG or IGT compared with NGT. Multiregression analysis showed that plasma NOx levels were inversely correlated with BMI in T2D whereas no association was found between plasma NOx levels and BMI in non-diabetic subjects. Moreover, there was no correlation between plasma NOx levels and homeostasis model assessment-insulin resistance (HOMA-IR) in both diabetic and non-diabetic subjects. Conclusion: Plasma NOx levels did not predict glucose intolerance or insulin resistance before the development of T2D and the increase in plasma NOx levels in T2D was not caused by adiposity. Thus, plasma NOx is not a useful marker for the prediction of high-risk subjects for T2D among Vietnamese.

Environmental science and pollution research international, Jan 17, 2014

The Bien Hoa airbase (south of Vietnam) is known as one of the Agent Orange hotspots which have b... more The Bien Hoa airbase (south of Vietnam) is known as one of the Agent Orange hotspots which have been seriously contaminated by Agent Orange/dioxin during the Vietnam War. Hundreds of samples including soil, sediment and fish were collected at the Bien Hoa Agent Orange hotspot for assessment of the environmental contamination caused by dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The toxicity equivalency quotient (TEQ) concentration of PCDD/Fs in soil and sediment varied from 7.6 to 962,000 and 17 to 4860 pg/g dry wt, respectively, implying very high contamination of PCDD/Fs in several areas. PCDD/F levels in fish ranged between 1.8 and 288 pg/g TEQ wet wt and was generally higher than advisory guidelines for food consumption. 2,3,7,8-Tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) contributed 66-99 % of TEQ for most of the samples, suggesting 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) from Agent Orange as the major source of the contamination. The vertical trans...

Urology, 2009

To present the diagnostic results of contrast vaginography to detect a vaginal ectopic ureter, in... more To present the diagnostic results of contrast vaginography to detect a vaginal ectopic ureter, in addition to investigation with ultrasonography, intravenous urography, and technetium-99m-dimercaptosuccinic acid renal scan. A single ectopic ureter is a rare anomaly. Eighteen girls with a single ectopic ureter were treated at the Children's Hospital No. 1 from 1995 to August 2008. The diagnostic studies included ultrasonography, intravenous urography, renal scans, and, finally, vaginography with contrast if the renal scans could not detect the poorly functioning kidneys. Intravenous urography showed a poorly functioning kidney in 1 patient. Another 10 poorly functioning kidneys were revealed by technetium-99m-dimercaptosuccinic acid renal scan, but 7 kidneys were not identifiable using contrast, ultrasonography, or radionuclide. Of these 7 patients, 6 vaginal ectopic ureters were detected using contrast vaginography. All 18 dysplastic kidneys were surgically removed. The results of the study have demonstrated the satisfactory diagnostic value of vaginography as an imaging technique to detect the dysplastic kidney draining by a single ectopic ureter.

Toxicological & Environmental Chemistry, 2011

Human exposure to polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF), especially 2,3,... more Human exposure to polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF), especially 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD), was investigated in Vietnam since initial severe adverse health effects were reported in the late 1970s. The purpose of this study was to determine the effects of dioxin exposure on steroid hormones of primiparae in an Agent Orange/dioxin hot-spot and a non-exposed area in Vietnam. Sixteen primiparae (8 at each site), all of whom were aged between 20 and 30 years with infants aged between 4 and 16 weeks, agreed to participate in this study. The mean dioxin levels in breast milk of primiparae from the hot-spot area, in terms of PCDD, PCDF, and PCDD þ PCDF toxic equivalents (TEQ), were significantly higher than those for the non-exposed area. PCDD TEQ, PCDF TEQ, and PCDD þ PCDF TEQ levels showed a significant correlation with dehydroepiandrosterone (DHEA), androstenedione (A-dione), and estradiol (E2) in the saliva of primiparae in a combination of hot-spot and non-exposed areas in Vietnam. The dose-response curve between salivary E2 or A-dione levels and dioxin levels was U-shaped in humans. This study provides an overview of studies regarding dioxin hot-spots and effects on human health and steroid hormone levels in particular, with a focus on the toxicity attributed to dioxins and furans. Furthermore, causal evidence regarding the effects of dioxins on endocrine disruption in humans is provided.

The International Journal of Biochemistry & Cell Biology, 2013

Dicarbonyl/l-xylulose reductase (DCXR) is a highly conserved and phylogenetically widespread enzy... more Dicarbonyl/l-xylulose reductase (DCXR) is a highly conserved and phylogenetically widespread enzyme converting l-xylulose into xylitol. It also reduces highly reactive ␣-dicarbonyl compounds, thus performing a dual role in carbohydrate metabolism and detoxification. Enzymatic properties of DCXR from yeast, fungi and mammalian tissue extracts are extensively studied. Deficiency of the DCXR gene causes a human clinical condition called pentosuria and low DCXR activity is implicated in age-related diseases including cancers, diabetes, and human male infertility. While mice provide a model to study clinical condition of these diseases, it is necessary to adopt a physiologically tractable model in which genetic manipulations can be readily achieved to allow the fast genetic analysis of an enzyme with multiple biological roles. Caenorhabditis elegans has been successfully utilized as a model to study DCXR. Here, we discuss the biochemical properties and significance of DCXR activity in various human diseases, and the utility of C. elegans as a research platform to investigate the molecular and cellular mechanism of the DCXR biology.