Tran Huy Hau - Academia.edu (original) (raw)

Papers by Tran Huy Hau

Sexually Transmitted Infections, 2007

To determine changes in the prevalence of sexually transmitted infection (STI)/HIV in female sex ... more To determine changes in the prevalence of sexually transmitted infection (STI)/HIV in female sex workers (FSWs) after a community HIV prevention intervention project in five border provinces of Vietnam. Methods: The project focused on providing user-friendly STI services for FSWs using mobile teams operating at multiple sites depending on local client preferences. 911 FSWs were enrolled at baseline and 982 in the exit survey. Study participants were interviewed about sociodemographic characteristics, sexual behaviour, history of STIs and selected features of their husbands or cohabiting partners, and were tested for STIs. Results: The overall prevalence rates of HIV, syphilis, herpes simplex virus 2 (HSV-2) antibodies, gonorrhoea (GC), Chlamydia trachomatis (CT), and GC and/or CT among FSWs in the five border provinces in 2004 were 3.6%, 12.9%, 24.9%, 2.9%, 9.1% and 11.3%, respectively. Compared with baseline values, GC and/or CT decreased significantly from 19.9% to 11.3%, GC from 10.7% to 2.9% and CT from 11.9% to 9.1%. HIV decreased from 4.5% to 3.6%, and HSV-2 antibodies from 27.7% to 24.9%. After adjustment for possible confounders, a significant overall decrease in having GC and/or CT (OR = 0.46, 95% CI 0.33 to 0.65; p,0.001) and GC alone (OR = 0.22, 95% CI 0.13 to 0.37; p,0.001) was found, and the overall prevalence of syphilis increased significantly (OR = 1.55, 95% CI 1.11 to 2.17 p = 0.011). A marked increase in syphilis from 1.0% to 14.1% was identified in the Lai Chau province. Conclusions: Implementation of the project was associated with a reduction in GC and/or CT infections in FSWs, more so with GC than with CT. A notable increase in syphilis in Lai Chau was identified. HIV/STI interventions in FSWs can be implemented by government services and should be intensified and expanded to other provinces.

Optical Materials, 2013

We report the first demonstration of superbroadband emission extending from 1.30 to 1.68 μm in pr... more We report the first demonstration of superbroadband emission extending from 1.30 to 1.68 μm in praseodymium(Pr 3+)-erbium(Er 3+) codoped fluorotellurite glasses under 488 nm excitation. This superbroad near-infrared emission is contributed by the Pr 3+ : 1 D 2 → 1 G 4 and Er 3+ : 4 I 13/2 → 4 I 15/2 transitions which lead to emissions located at 1.48 and 1.53 μm, respectively. The quenching of the Pr 3+ emission resulted from the cross relaxation [ 1 D 2 , 3 H 4 ]→[ 1 G 4 , 3 F 3,4 ] was effectively compensated by the codoping of Er 3+. The results suggest that, other than the heavy-metal and transition-metal elements of active bismuth (Bi), nickel (Ni), chromium (Cr), etc., Pr 3+-Er 3+ codoped system is a promising alternative for the broadband near-infrared emission covering the expanded low-loss window.

Journal of Physics and Chemistry of Solids, 2012

Abstract The Bi–Tm–Er co-doped SiO 2 –Al 2 O 3 –La 2 O 3 (SAL) glasses, which exhibited a broadba... more Abstract The Bi–Tm–Er co-doped SiO 2 –Al 2 O 3 –La 2 O 3 (SAL) glasses, which exhibited a broadband near-infrared (NIR) emission, were investigated by the optical absorption and photoluminescence spectra. A super broadband NIR emission extending from 0.95 to 1.6 μm with a full-width at half-maximum (FWHM) of 430 nm which covered the whole O, E, S, C and L bands, was observed in Bi–Tm–Er co-doped samples under 808 nm excitation, as a result of the overlap of the Bi-related emission band (centered at 1270 nm) and the emission from Tm 3+ 3 H 4 → 3 F 4 transition (1450 nm) as well as Er 3+ 4 I 13/2 → 4 I 15/2 transition (1545 nm). In addition, a super broadband emission with amplitude relatively flat from 0.95 to 2.1 μm has been observed. The possible energy transfer between Bi-related centers, Tm 3+ ions and Er 3+ ions was proposed.

Journal of Non-Crystalline Solids, 2013

Transparent glass-ceramics SiO 2-AlF 3-BaF 2-TiO 2-LaF 3 (SABTL) containing Ba 2 LaF 7 nanocrysta... more Transparent glass-ceramics SiO 2-AlF 3-BaF 2-TiO 2-LaF 3 (SABTL) containing Ba 2 LaF 7 nanocrystals were successfully prepared by heat treatment process through conventional melting method. The crystal size in the glass-ceramics increased gradually under the changing of heat treatment temperatures and times, which was confirmed by the results of XRD, TEM measurements. The intensity of the blue, green and red upconversion luminescence around 490 nm, 525 nm, 546 nm, 657 nm which originate from the transitions 5 D 4 ? 7 F J (J = 6 and 5) of Tb 3+ ions and (2 H 11/2 , 4 S 3/2 , 4 F 9/2) ? 4 I 15/2 transitions of Er 3+ ions, respectively, were strongly observed after heat treatment under 980 nm laser diode excitation. The intensity of upconversion luminescence was increased gradually with the increase of Yb 3+ concentrations and reaches its maximum at 2.5 mol%. The upconversion luminescence and energy transfer process between Tb 3+ , Yb 3+ and Er 3+ ions in the glass-ceramics were discussed.

Journal of Luminescence, 2012

The Bi-Tm co-doped SiO 2-Al 2 O 3-La 2 O 3 (SAL) glasses, which exhibited a broadband near-infrar... more The Bi-Tm co-doped SiO 2-Al 2 O 3-La 2 O 3 (SAL) glasses, which exhibited a broadband near-infrared (NIR) emission was investigated by the optical absorption and photoluminescence spectra. The super broadband near-infrared emission from 1000 to 2100 nm, which covered the whole O, E, S, C and L bands, was observed in the Bi-Tm co-doped samples, as a result of the overlap of the Bi-related emission band (centered at 1270 nm) and the emission from Tm 3 þ 3 H 4-3 F 4 transition (1440 nm) as well as Tm 3 þ 3 F 4-3 H 6 transition (1800 nm). Relative luminescence intensity at 1270, 1440 and 1800 nm wavelength varied depending on the mixing ratio of Bi and Tm and the full-width at halfmaximum (FWHM) extending from 1000 to 1600 nm could be 400 nm. These results indicated that Bi-Tm co-doped SiO 2-Al 2 O 3-La 2 O 3 glasses could provide potential applications in tunable lasers as well as the broadband optical amplifiers in WDM system.

Sexually Transmitted Infections, 2007

To determine changes in the prevalence of sexually transmitted infection (STI)/HIV in female sex ... more To determine changes in the prevalence of sexually transmitted infection (STI)/HIV in female sex workers (FSWs) after a community HIV prevention intervention project in five border provinces of Vietnam. Methods: The project focused on providing user-friendly STI services for FSWs using mobile teams operating at multiple sites depending on local client preferences. 911 FSWs were enrolled at baseline and 982 in the exit survey. Study participants were interviewed about sociodemographic characteristics, sexual behaviour, history of STIs and selected features of their husbands or cohabiting partners, and were tested for STIs. Results: The overall prevalence rates of HIV, syphilis, herpes simplex virus 2 (HSV-2) antibodies, gonorrhoea (GC), Chlamydia trachomatis (CT), and GC and/or CT among FSWs in the five border provinces in 2004 were 3.6%, 12.9%, 24.9%, 2.9%, 9.1% and 11.3%, respectively. Compared with baseline values, GC and/or CT decreased significantly from 19.9% to 11.3%, GC from 10.7% to 2.9% and CT from 11.9% to 9.1%. HIV decreased from 4.5% to 3.6%, and HSV-2 antibodies from 27.7% to 24.9%. After adjustment for possible confounders, a significant overall decrease in having GC and/or CT (OR = 0.46, 95% CI 0.33 to 0.65; p,0.001) and GC alone (OR = 0.22, 95% CI 0.13 to 0.37; p,0.001) was found, and the overall prevalence of syphilis increased significantly (OR = 1.55, 95% CI 1.11 to 2.17 p = 0.011). A marked increase in syphilis from 1.0% to 14.1% was identified in the Lai Chau province. Conclusions: Implementation of the project was associated with a reduction in GC and/or CT infections in FSWs, more so with GC than with CT. A notable increase in syphilis in Lai Chau was identified. HIV/STI interventions in FSWs can be implemented by government services and should be intensified and expanded to other provinces.

Optical Materials, 2013

We report the first demonstration of superbroadband emission extending from 1.30 to 1.68 μm in pr... more We report the first demonstration of superbroadband emission extending from 1.30 to 1.68 μm in praseodymium(Pr 3+)-erbium(Er 3+) codoped fluorotellurite glasses under 488 nm excitation. This superbroad near-infrared emission is contributed by the Pr 3+ : 1 D 2 → 1 G 4 and Er 3+ : 4 I 13/2 → 4 I 15/2 transitions which lead to emissions located at 1.48 and 1.53 μm, respectively. The quenching of the Pr 3+ emission resulted from the cross relaxation [ 1 D 2 , 3 H 4 ]→[ 1 G 4 , 3 F 3,4 ] was effectively compensated by the codoping of Er 3+. The results suggest that, other than the heavy-metal and transition-metal elements of active bismuth (Bi), nickel (Ni), chromium (Cr), etc., Pr 3+-Er 3+ codoped system is a promising alternative for the broadband near-infrared emission covering the expanded low-loss window.

Journal of Physics and Chemistry of Solids, 2012

Abstract The Bi–Tm–Er co-doped SiO 2 –Al 2 O 3 –La 2 O 3 (SAL) glasses, which exhibited a broadba... more Abstract The Bi–Tm–Er co-doped SiO 2 –Al 2 O 3 –La 2 O 3 (SAL) glasses, which exhibited a broadband near-infrared (NIR) emission, were investigated by the optical absorption and photoluminescence spectra. A super broadband NIR emission extending from 0.95 to 1.6 μm with a full-width at half-maximum (FWHM) of 430 nm which covered the whole O, E, S, C and L bands, was observed in Bi–Tm–Er co-doped samples under 808 nm excitation, as a result of the overlap of the Bi-related emission band (centered at 1270 nm) and the emission from Tm 3+ 3 H 4 → 3 F 4 transition (1450 nm) as well as Er 3+ 4 I 13/2 → 4 I 15/2 transition (1545 nm). In addition, a super broadband emission with amplitude relatively flat from 0.95 to 2.1 μm has been observed. The possible energy transfer between Bi-related centers, Tm 3+ ions and Er 3+ ions was proposed.

Journal of Non-Crystalline Solids, 2013

Transparent glass-ceramics SiO 2-AlF 3-BaF 2-TiO 2-LaF 3 (SABTL) containing Ba 2 LaF 7 nanocrysta... more Transparent glass-ceramics SiO 2-AlF 3-BaF 2-TiO 2-LaF 3 (SABTL) containing Ba 2 LaF 7 nanocrystals were successfully prepared by heat treatment process through conventional melting method. The crystal size in the glass-ceramics increased gradually under the changing of heat treatment temperatures and times, which was confirmed by the results of XRD, TEM measurements. The intensity of the blue, green and red upconversion luminescence around 490 nm, 525 nm, 546 nm, 657 nm which originate from the transitions 5 D 4 ? 7 F J (J = 6 and 5) of Tb 3+ ions and (2 H 11/2 , 4 S 3/2 , 4 F 9/2) ? 4 I 15/2 transitions of Er 3+ ions, respectively, were strongly observed after heat treatment under 980 nm laser diode excitation. The intensity of upconversion luminescence was increased gradually with the increase of Yb 3+ concentrations and reaches its maximum at 2.5 mol%. The upconversion luminescence and energy transfer process between Tb 3+ , Yb 3+ and Er 3+ ions in the glass-ceramics were discussed.

Journal of Luminescence, 2012

The Bi-Tm co-doped SiO 2-Al 2 O 3-La 2 O 3 (SAL) glasses, which exhibited a broadband near-infrar... more The Bi-Tm co-doped SiO 2-Al 2 O 3-La 2 O 3 (SAL) glasses, which exhibited a broadband near-infrared (NIR) emission was investigated by the optical absorption and photoluminescence spectra. The super broadband near-infrared emission from 1000 to 2100 nm, which covered the whole O, E, S, C and L bands, was observed in the Bi-Tm co-doped samples, as a result of the overlap of the Bi-related emission band (centered at 1270 nm) and the emission from Tm 3 þ 3 H 4-3 F 4 transition (1440 nm) as well as Tm 3 þ 3 F 4-3 H 6 transition (1800 nm). Relative luminescence intensity at 1270, 1440 and 1800 nm wavelength varied depending on the mixing ratio of Bi and Tm and the full-width at halfmaximum (FWHM) extending from 1000 to 1600 nm could be 400 nm. These results indicated that Bi-Tm co-doped SiO 2-Al 2 O 3-La 2 O 3 glasses could provide potential applications in tunable lasers as well as the broadband optical amplifiers in WDM system.