We consider current-induced domain wall motion and, the reciprocal process, moving domain wall-in... more We consider current-induced domain wall motion and, the reciprocal process, moving domain wall-induced current. The associated Onsager coefficients are expressed in terms of scattering matrices. Uncommonly, in (Ga,Mn)As, the effective Gilbert damping coefficient $\alpha_w$ and the effective out-of-plane spin transfer torque parameter $\beta_w$ are dominated by spin-orbit interaction in combination with scattering off the domain wall, and not scattering off extrinsic impurities. Numerical calculations give $\alpha_w \sim 0.01$ and $\beta_w \sim 1$ in dirty (Ga,Mn)As. The extraordinary large $\beta_w$ parameter allows experimental detection of current or voltage induced by domain wall motion in (Ga,Mn)As.
Water multiples can be very strong and contaminate the primary reflections. This can cause proble... more Water multiples can be very strong and contaminate the primary reflections. This can cause problems in the processing flow and the interpretation of the subsurface image. Hence, multiples suppression is an important part of the preprocessing flow. We present a fast workflow for attenuation of free surface related multiples for 2D and 3D ocean bottom seismic data based on the wave equation approach. Included in the workflow are: 1. Calibration of the pressure and vertical velocity components by using wavefield splitting. 2. Data interpolation by using offset projection. 3. Fast Radon transform by using fast fractional Fourier transform. Advantages of this workflow are that it is fast, efficient and the only requirements are the recording of both pressure and vertical particle components at some point below the source in the water column.
A phase transition within the molten phase of the Abrikosov vortex system without disorder in ext... more A phase transition within the molten phase of the Abrikosov vortex system without disorder in extreme type-II superconductors is found via large-scale Monte-Carlo simulations. It involves breaking a U(1)-symmetry, and has a zero-field counterpart, unlike vortex lattice melting. Its hallmark is the loss of number-conservation of connected vortex paths threading the entire system {\it in any direction}, driving the vortex line tension to zero. This tension plays the role of a generalized ``stiffness'' of the vortex liquid, and serves as a probe of the loss of order at the transition, where a weak specific heat anomaly is found.
We study the effect of critical fluctuations on the $(B,T)$ phase diagram in extreme type-II supe... more We study the effect of critical fluctuations on the $(B,T)$ phase diagram in extreme type-II superconductors in zero and finite magnetic field using large-scale Monte Carlo simulations on the Ginzburg-Landau model in a frozen gauge approximation. We show that a vortex-loop unbinding gives a correct picture of the zero field superconducting-normal transition even in the presence of amplitude fluctuations, which are far from being critical at $T_c$. We extract critical exponents of the dual model by studying the topological excitations of the original model. From the vortex-loop distribution function we extract the anomalous dimension of the dual field $\eta \simeq -0.18$, and conclude that the charged Ginzburg-Landau model and the neutral 3DXY model belong to different universality classes. We find are two distinct scaling regimes for the vortex-line lattice melting line: a high-field scaling regime and a distinct low-field 3DXY critical scaling regime. We also find indications of an abrupt change in the connectivity of the vortex-tangle in the vortex liquid along a line $T_L \geq T_M$. This is the finite field counter-part of the zero-field vortex-loop blowout. Which at low enough fields appears to coincide with $T_M$. Here, a description of the vortex system only in terms of field induced vortex lines is inadequate at and above the VLL melting temperature.
There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is... more There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictive. The theory uses analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. It applies to single-channel topographies and estuaries that demonstrate moderate tidal damping. The Mekong delta is a multi-channel estuary where the tide is damped due to a relatively strong river discharge (in the order of 2000 m 3 /s), even during the dry season. As a result the Mekong is a strongly riverine estuary. This paper aims to test if the theory can be applied to such a riverine multichannel estuary, and to see if possible adjustments or generalisations need to be made. The paper presents salt intrusion measurements that were done by moving boat in 2005, to which the salt intrusion model was calibrated. The theory has been expanded to cater for tidal damping. Subsequently the model has been validated with observations made at fixed locations over the years 1998 and 1999. Finally it has been tested whether the Mekong calibration fits the overall predictive equations derived in other estuaries. The test has been successful and led to a slight adjustment of the predictive equation to cater for estuaries that experience a sloping bottom.
An innovative quick-closing probe system was designed, built, and tested for measuring the local ... more An innovative quick-closing probe system was designed, built, and tested for measuring the local particulate phase density of gas-particle suspensions. Experiments with glass beads and powder coals were conducted in a horizontal channel with an aspect ratio of 11 to 1, and also in a 0·25 m I.D. bench-scale vortex chamber. Results of particle density distributions in these two systems indicated
The solubilities of lanthanum carbonate La2(CO3)3·8H2O in solutionsS 0([H+]=H mol kg−1, [Na+]=(I−... more The solubilities of lanthanum carbonate La2(CO3)3·8H2O in solutionsS 0([H+]=H mol kg−1, [Na+]=(I−H) mol kg−1, [ClO 4 − ]=I mol kg−1) at various fixed partial pressures of CO2 have been investigated at 25.0 °C. The hydrogen ion molality and the total molality of La(III) ion in equilibrium with the solid phase were determined by e.m.f. and analytical methods, respectively. The stoichiometric solubility constants $$\log ^ \star K_{ps0}^I = \log \{ [La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} \}$$ according to the overall reaction $$1/2La_2 (CO_3 )_3 \cdot 8H_2 O + 3H^ + \rightleftharpoons La^{3 + } + 3/2CO_2 + 11/2H_2 O$$ have the values 10.23, 10.37, 10.58, 10.77 and 11.06 forI=0.1, 0.25, 1.0, 2.0 and 4.0 mol kg−1 (Na)ClO4, respectively. The extrapolation to infinite dilution using the Pitzer equations resulted in a “thermodynamic” solubility constant: $$\log ^ \star K_{ps0}^0 = \log \{ ([La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} )(\gamma _{La^3 } + \gamma _{H^ + }^{ - 3} )a_{H_2 O}^{11/2} \} = 9.57 \pm 0.05$$ . This in turn led to the Gibbs energy of lanthanite, La2(CO3)3·8H2O, formation: $$\Delta _f G_{298}^{O - } = - 5048.4 kJ mol^{ - 1}$$ . Die Löslichkeit von Lanthancarbonat La2(CO3)3·8H2O in LösungenS 0([H+]=H mol kg−1, [Na+]=(I−H) mol kg−1, [ClO 4 − ]=I mol kg−1) wurde bei 25.0 °C und verschiedenen, konstanten Partialdrücken von CO2 untersucht. Die Molalität der Wasserstoff- und die totale Molalität der La(III)-Ionen im Gleichgewicht mit der festen Phase wurden potentiometrisch bzw. analytisch bestimmt. Für die stöchiometrischen Löslichkeitskonstanten $$\log ^ \star K_{ps0}^I = \log \{ [La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} \}$$ entsprechend der Gesamtreaktion $$1/2La_2 (CO_3 )_3 \cdot 8H_2 O + 3H^ + \rightleftharpoons La^{3 + } + 3/2CO_2 + 11/2H_2 O$$ wurden beiI=0.1, 0.25, 1.0, 2.0 und 4.0 mol kg−1 (Na)ClO4, folgende Werte gefunden: 10.23, 10.37, 10.58, 10.77 und 11.06. Die Extrapolation auf unendliche Verdünnung mit Hilfe der Pitzer-Gleichungen führte zu einer „thermodynamischen“ Löslichkeitskonstante von: $$\log ^ \star K_{ps0}^0 = \log \{ ([La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} )(\gamma _{La^3 } + \gamma _{H^ + }^{ - 3} )a_{H_2 O}^{11/2} \} = 9.57 \pm 0.05$$ . Mit dieser ergab sich die freie Bildungsenthalpie von Lanthanit La2(CO3)3·8H2: zu: $$\Delta _f G_{298}^{O - } = - 5048.4 kJ mol^{ - 1}$$ .
In our efforts to develop novel hydrophilic monolithic porous materials for use as supports in li... more In our efforts to develop novel hydrophilic monolithic porous materials for use as supports in liquid chromatographic separation of proteins, polymers based on epoxy monomers and diamines as curing agents were synthesized. The epoxy dispersed phase was emulsified in an aqueous phase containing the amine with the aid of a nonionic polymeric surfactant, and the resulting emulsions were thermally polymerized. Various factors, namely, the type of epoxy component, levels of reactants, type and concentration of diluents, and curing procedures, were studied to obtain suitable morphology and adequate mechanical properties for their intended use. Characterization of their morphologies and porous properties was done using scanning electron microscopy, nitrogen adsorption/desorption measurement (BET method), mercury intrusion porosimetry, and X-ray photoelectron spectroscopy.
This paper is the first installment of a multi-paper series concerned with simulating the potenti... more This paper is the first installment of a multi-paper series concerned with simulating the potential vulnerability of groundwater in Fresno County (California) to contamination resulting from long-term, agriculture related, applications of the nematocide DBCP. In this paper our focus is on the surface and the unsaturated subsurface. Using PRZM-2, we quantitatively estimate, for a 35 year period, the potential fate and transport of DBCP between the surface and the water table for multiple non-point source applications, related to different and changing land-use, between 1960 and 1977. Our transport simulations include consideration for advection, decay, sorption, and volatilization. The results presented here indicate tremendous spatial and temporal variability in DBCP loading at the water table at the regional scale. Our simulations also suggest that the DBCP loading to the water table, resulting from the legacy of the chemical's use, is currently well below the detectable limit. The characterization of spatially variable DBCP loadings to the saturated subsurface through time, which are presented in this paper, is used as input for the 3-D groundwater models of DBCP fate and transport in Fresno County between 1960 and 1994 that are reported in the companion paper (Loague et al., 1997).
For the site-specific prescription of fertilizer topdressing in rice cultivation, a non-destructi... more For the site-specific prescription of fertilizer topdressing in rice cultivation, a non-destructive diagnosis of the rice growth and nutrition status is necessary. Three experiments were done to develop and test a model using canopy reflectance for the non-destructive diagnosis of plant growth and N status in rice. Two experiments for model development were conducted, one in 2000 and another in 2003 in Suwon, Korea, including two rice varieties and four nitrogen (N) rates in 2000 and four rice varieties and 10 N treatments in 2003. Hyperspectral canopy reflectance (300–1,100 nm) data recorded at various growth stages before heading were used to develop a partial least squares regression (PLS) model to calculate plant biomass and N nutrition status. The 342 observations were split for model calibration (75%) and validation (25%). The PLS model was then tested to calculate within-field statistical variation of four crop variables: shoot dry weight (SDW), shoot N concentration (SN), shoot N density (SND) and N nutrition index (NNI) using measured canopy reflectance data from a field of 6,500 m2 in 2004. Results showed that PLS regression using logarithm reflectance had better performance than both the PLS and multiple stepwise linear regression (MSLR) models using original reflectance data to calculate the four plant variables in year 2000 and 2003. It produced values with an acceptable model coefficient of determination (R 2) and relative error of calculation (REC). The model R 2 and REC ranged from .83 to .89 and 13.4% to 22.8% for calibration, and .76 to .87 and 14.0% to 24.4% for validation, respectively. The PLS regression model R 2 was reduced in the test data of year 2004 but the root mean square error of calculation (RMSEC) was smaller, suggesting that the PLS regression model using canopy reflectance data could be a promising method to calculate within-field spatial variation of rice crop growth and N status.
Histone methylation plays an important role in regulating gene expression. One such methylation o... more Histone methylation plays an important role in regulating gene expression. One such methylation occurs at Lys 79 of histone H3 (H3K79) and is catalyzed by the yeast DOT1 (disruptor of telomeric silencing) and its mammalian homolog, DOT1L. Previous studies have demonstrated that germline disruption of Dot1L in mice resulted in embryonic lethality. Here we report that cardiac-specific knockout of Dot1L results in increased mortality rate with chamber dilation, increased cardiomyocyte cell death, systolic dysfunction, and conduction abnormalities. These phenotypes mimic those exhibited in patients with dilated cardiomyopathy (DCM). Mechanistic studies reveal that DOT1L performs its function in cardiomyocytes through regulating Dystrophin (Dmd) transcription and, consequently, stability of the Dystrophin-glycoprotein complex important for cardiomyocyte viability. Importantly, expression of a miniDmd can largely rescue the DCM phenotypes, indicating that Dmd is a major target mediating DOT1L function in cardiomyocytes. Interestingly, analysis of available gene expression data sets indicates that DOT1L is down-regulated in idiopathic DCM patient samples compared with normal controls. Therefore, our study not only establishes a critical role for DOT1L-mediated H3K79 methylation in cardiomyocyte function, but also reveals the mechanism underlying the role of DOT1L in DCM. In addition, our study may open new avenues for the diagnosis and treatment of human heart disease.
Chromosomal translocations of the mixed lineage leukemia (MLL) gene are a common cause of acute l... more Chromosomal translocations of the mixed lineage leukemia (MLL) gene are a common cause of acute leukemias. The oncogenic function of MLL fusion proteins is, in part, mediated through aberrant activation of Hoxa genes and Meis1, among others. Here we demonstrate using a tamoxifen-inducible Cre-mediated loss of function mouse model that DOT1L, an H3K79 methyltransferase, is required for both initiation and maintenance of MLL-AF9-induced leukemogenesis in vitro and in vivo. Through gene expression and chromatin immunoprecipitation analysis we demonstrate that mistargeting of DOT1L, subsequent H3K79 methylation, and up-regulation of Hoxa and Meis1 genes underlie the molecular mechanism of how DOT1L contributes to MLL-AF9-mediated leukemogenesis. Our study not only provides the first in vivo evidence for the function of DOT1L in leukemia, but also reveals the molecular mechanism for DOT1L in MLL-AF9 mediated leukemia. Thus, DOT1L may serve as a potential therapeutic target for the treatment of leukemia caused by MLL translocations.
DOT1 (disruptor of telomeric silencing; also called Kmt4) was initially discovered in budding yea... more DOT1 (disruptor of telomeric silencing; also called Kmt4) was initially discovered in budding yeast in a genetic screen for genes whose deletion confers defects in telomeric silencing. Since the discovery ∼10 years ago that Dot1 and its mammalian homolog, DOT1L (DOT1-Like), possess histone methyltransferase activity toward histone H3 Lys 79, great progress has been made in characterizing their enzymatic activities and the role of Dot1/DOT1L-mediated H3K79 methylation in transcriptional regulation, cell cycle regulation, and the DNA damage response. In addition, gene disruption in mice has revealed that mouse DOT1L plays an essential role in embryonic development, hematopoiesis, cardiac function, and the development of leukemia. The involvement of DOT1L enzymatic activity in leukemogenesis driven by a subset of MLL (mixed-lineage leukemia) fusion proteins raises the possibility of targeting DOT1L for therapeutic intervention.
This study was aimed at determining the molecular epidemiology of rabies virus (RABV) circulating... more This study was aimed at determining the molecular epidemiology of rabies virus (RABV) circulating in Vietnam. Intra vitam samples (saliva and cerebrospinal fluid) were collected from 31 patients who were believed to have rabies and were admitted to hospitals in northern provinces of Vietnam. Brain samples were collected from 176 sick or furious rabid dogs from all over the country. The human and canine samples were subjected to reverse transcription-polymerase chain reaction analysis. The findings showed that 23 patients tested positive for RABV. Interestingly, 5 rabies patients did not have any history of dog or cat bites, but they had an experience of butchering dogs or cats, or consuming their meat. RABV was also detected in 2 of the 100 sick dogs from slaughterhouses. Molecular epidemiological analysis of 27 RABV strains showed that these viruses could be classified into two groups. The RABVs classified into Group 1 were distributed throughout Vietnam and had sequence similarity with the strains from China, Thailand, Malaysia, and the Philippines. However, the RABVs classified into Group 2 were only found in the northern provinces of Vietnam and showed high sequence similarity with the strain from southern China. This finding suggested the recent influx of Group 2 RABVs between Vietnam and China across the border. Although the incidence of rabies due to circulating RABVs in slaughterhouses is less common than that due to dog bite, the national program for rabies control and prevention in Vietnam should include monitoring of the health of dogs meant for human consumption and vaccination for workers at dog slaughterhouses. Further, monitoring of and research on the circulating RABVs in dog markets may help to determine the cause of rabies and control the spread of rabies in slaughterhouses in Vietnam.
Bacterial degradation of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) has been previously r... more Bacterial degradation of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) has been previously reported, however, its degradation enzyme system has not been characterized. In this study, a DDEdegrading bacterium, Janibacter sp. TYM3221, was isolated and characterized. Transformation of DDE was demonstrated by TYM3211 resting cells grown in LB in the presence and absence of biphenyl. Gas chromatography-mass spectrometry analysis revealed five metabolites of DDE containing a meta-ring cleavage product and 4-chlorobenzoic acid, suggesting that TYM3221 degrades DDE to 4-chlorobenzoic acid via a meta-ring cleavage product. A gene cluster, bphAaAbAcAd, which codes for biphenyl dioxygenase subunits, was cloned from TYM3221. A mutant strain with a bphAa-gene inactivation did not grow on biphenyl, and showed no DDE degradation activity. These results indicate that in strain TYM3221, the bphAa-coded biphenyl dioxygenase is involved not only in the metabolism of biphenyl but also in the degradation of DDE.
Previously three oncogene transgenic zebrafish lines with inducible expression of xmrk, kras or M... more Previously three oncogene transgenic zebrafish lines with inducible expression of xmrk, kras or Myc in the liver have been generated and these transgenic lines develop oncogene-addicted liver tumors upon chemical induction. In the current study, comparative transcriptomic approaches were used to examine the correlation of the three induced transgenic liver cancers with human liver cancers. RNA profiles from the three zebrafish tumors indicated relatively small overlaps of significantly deregulated genes and biological pathways. Nevertheless, the three transgenic tumor signatures all showed significant correlation with advanced or very advanced human hepatocellular carcinoma (HCC). Interestingly, molecular signature from each oncogene-induced zebrafish liver tumor correlated with only a small subset of human HCC samples (24-29%) and there were conserved up-regulated pathways between the zebrafish and correlated human HCC subgroup. The three zebrafish liver cancer models together represented nearly half (47.2%) of human HCCs while some human HCCs showed significant correlation with more than one signature defined from the three oncogene-addicted zebrafish tumors. In contrast, commonly deregulated genes (21 up and 16 down) in the three zebrafish tumor models generally showed accordant deregulation in the majority of human HCCs, suggesting that these genes might be more consistently deregulated in a broad range of human HCCs with different molecular mechanisms and thus serve as common diagnosis markers and therapeutic targets. Thus, these transgenic zebrafish models with well-defined oncogene-induced tumors are valuable tools for molecular classification of human HCCs and for understanding of molecular drivers in hepatocarcinogenesis in each human HCC subgroup.
Hepatocellular carcinoma (HCC) is currently one of the top lethal cancers with an increasing tren... more Hepatocellular carcinoma (HCC) is currently one of the top lethal cancers with an increasing trend. Deregulation of MYC in HCC is frequently detected and always correlated with poor prognosis. As the zebrafish genome contains two differentially expressed zebrafish myc orthologs, myca and mycb, it remains unclear about the oncogenicity of the two zebrafish myc genes. In the present study, we developed two transgenic zebrafish lines to overexpress myca and mycb respectively in the liver using a mifepristone-inducible system and found that both myc genes were oncogenic. Moreover, the transgenic expression of myca in hepatocytes caused robust liver tumors with several distinct phenotypes of variable severity.~5% of myca transgenic fish developing multinodular HCC with cirrhosis after 8 months of induced myca expression. Apoptosis was also observed with myca expression; introduction of homozygous tp53 -/mutation into the myca transgenic fish reduced apoptosis and accelerated tumor progression. The malignant status of hepatocytes was dependent on continued expression of myca; withdrawal of the mifepristone inducer resulted in a rapid regression of liver tumors, and the tumor regression occurred even in the tp53 -/mutation background. Thus, our data demonstrated the robust oncogenicity of zebrafish myca and the requirement of sustained Myc overexpression for maintenance of the liver tumor phenotype in this transgenic model. Furthermore, tumor regression is independent of the function of Tp53.
We consider current-induced domain wall motion and, the reciprocal process, moving domain wall-in... more We consider current-induced domain wall motion and, the reciprocal process, moving domain wall-induced current. The associated Onsager coefficients are expressed in terms of scattering matrices. Uncommonly, in (Ga,Mn)As, the effective Gilbert damping coefficient $\alpha_w$ and the effective out-of-plane spin transfer torque parameter $\beta_w$ are dominated by spin-orbit interaction in combination with scattering off the domain wall, and not scattering off extrinsic impurities. Numerical calculations give $\alpha_w \sim 0.01$ and $\beta_w \sim 1$ in dirty (Ga,Mn)As. The extraordinary large $\beta_w$ parameter allows experimental detection of current or voltage induced by domain wall motion in (Ga,Mn)As.
Water multiples can be very strong and contaminate the primary reflections. This can cause proble... more Water multiples can be very strong and contaminate the primary reflections. This can cause problems in the processing flow and the interpretation of the subsurface image. Hence, multiples suppression is an important part of the preprocessing flow. We present a fast workflow for attenuation of free surface related multiples for 2D and 3D ocean bottom seismic data based on the wave equation approach. Included in the workflow are: 1. Calibration of the pressure and vertical velocity components by using wavefield splitting. 2. Data interpolation by using offset projection. 3. Fast Radon transform by using fast fractional Fourier transform. Advantages of this workflow are that it is fast, efficient and the only requirements are the recording of both pressure and vertical particle components at some point below the source in the water column.
A phase transition within the molten phase of the Abrikosov vortex system without disorder in ext... more A phase transition within the molten phase of the Abrikosov vortex system without disorder in extreme type-II superconductors is found via large-scale Monte-Carlo simulations. It involves breaking a U(1)-symmetry, and has a zero-field counterpart, unlike vortex lattice melting. Its hallmark is the loss of number-conservation of connected vortex paths threading the entire system {\it in any direction}, driving the vortex line tension to zero. This tension plays the role of a generalized ``stiffness'' of the vortex liquid, and serves as a probe of the loss of order at the transition, where a weak specific heat anomaly is found.
We study the effect of critical fluctuations on the $(B,T)$ phase diagram in extreme type-II supe... more We study the effect of critical fluctuations on the $(B,T)$ phase diagram in extreme type-II superconductors in zero and finite magnetic field using large-scale Monte Carlo simulations on the Ginzburg-Landau model in a frozen gauge approximation. We show that a vortex-loop unbinding gives a correct picture of the zero field superconducting-normal transition even in the presence of amplitude fluctuations, which are far from being critical at $T_c$. We extract critical exponents of the dual model by studying the topological excitations of the original model. From the vortex-loop distribution function we extract the anomalous dimension of the dual field $\eta \simeq -0.18$, and conclude that the charged Ginzburg-Landau model and the neutral 3DXY model belong to different universality classes. We find are two distinct scaling regimes for the vortex-line lattice melting line: a high-field scaling regime and a distinct low-field 3DXY critical scaling regime. We also find indications of an abrupt change in the connectivity of the vortex-tangle in the vortex liquid along a line $T_L \geq T_M$. This is the finite field counter-part of the zero-field vortex-loop blowout. Which at low enough fields appears to coincide with $T_M$. Here, a description of the vortex system only in terms of field induced vortex lines is inadequate at and above the VLL melting temperature.
There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is... more There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictive. The theory uses analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. It applies to single-channel topographies and estuaries that demonstrate moderate tidal damping. The Mekong delta is a multi-channel estuary where the tide is damped due to a relatively strong river discharge (in the order of 2000 m 3 /s), even during the dry season. As a result the Mekong is a strongly riverine estuary. This paper aims to test if the theory can be applied to such a riverine multichannel estuary, and to see if possible adjustments or generalisations need to be made. The paper presents salt intrusion measurements that were done by moving boat in 2005, to which the salt intrusion model was calibrated. The theory has been expanded to cater for tidal damping. Subsequently the model has been validated with observations made at fixed locations over the years 1998 and 1999. Finally it has been tested whether the Mekong calibration fits the overall predictive equations derived in other estuaries. The test has been successful and led to a slight adjustment of the predictive equation to cater for estuaries that experience a sloping bottom.
An innovative quick-closing probe system was designed, built, and tested for measuring the local ... more An innovative quick-closing probe system was designed, built, and tested for measuring the local particulate phase density of gas-particle suspensions. Experiments with glass beads and powder coals were conducted in a horizontal channel with an aspect ratio of 11 to 1, and also in a 0·25 m I.D. bench-scale vortex chamber. Results of particle density distributions in these two systems indicated
The solubilities of lanthanum carbonate La2(CO3)3·8H2O in solutionsS 0([H+]=H mol kg−1, [Na+]=(I−... more The solubilities of lanthanum carbonate La2(CO3)3·8H2O in solutionsS 0([H+]=H mol kg−1, [Na+]=(I−H) mol kg−1, [ClO 4 − ]=I mol kg−1) at various fixed partial pressures of CO2 have been investigated at 25.0 °C. The hydrogen ion molality and the total molality of La(III) ion in equilibrium with the solid phase were determined by e.m.f. and analytical methods, respectively. The stoichiometric solubility constants $$\log ^ \star K_{ps0}^I = \log \{ [La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} \}$$ according to the overall reaction $$1/2La_2 (CO_3 )_3 \cdot 8H_2 O + 3H^ + \rightleftharpoons La^{3 + } + 3/2CO_2 + 11/2H_2 O$$ have the values 10.23, 10.37, 10.58, 10.77 and 11.06 forI=0.1, 0.25, 1.0, 2.0 and 4.0 mol kg−1 (Na)ClO4, respectively. The extrapolation to infinite dilution using the Pitzer equations resulted in a “thermodynamic” solubility constant: $$\log ^ \star K_{ps0}^0 = \log \{ ([La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} )(\gamma _{La^3 } + \gamma _{H^ + }^{ - 3} )a_{H_2 O}^{11/2} \} = 9.57 \pm 0.05$$ . This in turn led to the Gibbs energy of lanthanite, La2(CO3)3·8H2O, formation: $$\Delta _f G_{298}^{O - } = - 5048.4 kJ mol^{ - 1}$$ . Die Löslichkeit von Lanthancarbonat La2(CO3)3·8H2O in LösungenS 0([H+]=H mol kg−1, [Na+]=(I−H) mol kg−1, [ClO 4 − ]=I mol kg−1) wurde bei 25.0 °C und verschiedenen, konstanten Partialdrücken von CO2 untersucht. Die Molalität der Wasserstoff- und die totale Molalität der La(III)-Ionen im Gleichgewicht mit der festen Phase wurden potentiometrisch bzw. analytisch bestimmt. Für die stöchiometrischen Löslichkeitskonstanten $$\log ^ \star K_{ps0}^I = \log \{ [La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} \}$$ entsprechend der Gesamtreaktion $$1/2La_2 (CO_3 )_3 \cdot 8H_2 O + 3H^ + \rightleftharpoons La^{3 + } + 3/2CO_2 + 11/2H_2 O$$ wurden beiI=0.1, 0.25, 1.0, 2.0 und 4.0 mol kg−1 (Na)ClO4, folgende Werte gefunden: 10.23, 10.37, 10.58, 10.77 und 11.06. Die Extrapolation auf unendliche Verdünnung mit Hilfe der Pitzer-Gleichungen führte zu einer „thermodynamischen“ Löslichkeitskonstante von: $$\log ^ \star K_{ps0}^0 = \log \{ ([La^{3 + } ]p_{CO_2 }^{3/2} [H^ + ]^{ - 3} )(\gamma _{La^3 } + \gamma _{H^ + }^{ - 3} )a_{H_2 O}^{11/2} \} = 9.57 \pm 0.05$$ . Mit dieser ergab sich die freie Bildungsenthalpie von Lanthanit La2(CO3)3·8H2: zu: $$\Delta _f G_{298}^{O - } = - 5048.4 kJ mol^{ - 1}$$ .
In our efforts to develop novel hydrophilic monolithic porous materials for use as supports in li... more In our efforts to develop novel hydrophilic monolithic porous materials for use as supports in liquid chromatographic separation of proteins, polymers based on epoxy monomers and diamines as curing agents were synthesized. The epoxy dispersed phase was emulsified in an aqueous phase containing the amine with the aid of a nonionic polymeric surfactant, and the resulting emulsions were thermally polymerized. Various factors, namely, the type of epoxy component, levels of reactants, type and concentration of diluents, and curing procedures, were studied to obtain suitable morphology and adequate mechanical properties for their intended use. Characterization of their morphologies and porous properties was done using scanning electron microscopy, nitrogen adsorption/desorption measurement (BET method), mercury intrusion porosimetry, and X-ray photoelectron spectroscopy.
This paper is the first installment of a multi-paper series concerned with simulating the potenti... more This paper is the first installment of a multi-paper series concerned with simulating the potential vulnerability of groundwater in Fresno County (California) to contamination resulting from long-term, agriculture related, applications of the nematocide DBCP. In this paper our focus is on the surface and the unsaturated subsurface. Using PRZM-2, we quantitatively estimate, for a 35 year period, the potential fate and transport of DBCP between the surface and the water table for multiple non-point source applications, related to different and changing land-use, between 1960 and 1977. Our transport simulations include consideration for advection, decay, sorption, and volatilization. The results presented here indicate tremendous spatial and temporal variability in DBCP loading at the water table at the regional scale. Our simulations also suggest that the DBCP loading to the water table, resulting from the legacy of the chemical's use, is currently well below the detectable limit. The characterization of spatially variable DBCP loadings to the saturated subsurface through time, which are presented in this paper, is used as input for the 3-D groundwater models of DBCP fate and transport in Fresno County between 1960 and 1994 that are reported in the companion paper (Loague et al., 1997).
For the site-specific prescription of fertilizer topdressing in rice cultivation, a non-destructi... more For the site-specific prescription of fertilizer topdressing in rice cultivation, a non-destructive diagnosis of the rice growth and nutrition status is necessary. Three experiments were done to develop and test a model using canopy reflectance for the non-destructive diagnosis of plant growth and N status in rice. Two experiments for model development were conducted, one in 2000 and another in 2003 in Suwon, Korea, including two rice varieties and four nitrogen (N) rates in 2000 and four rice varieties and 10 N treatments in 2003. Hyperspectral canopy reflectance (300–1,100 nm) data recorded at various growth stages before heading were used to develop a partial least squares regression (PLS) model to calculate plant biomass and N nutrition status. The 342 observations were split for model calibration (75%) and validation (25%). The PLS model was then tested to calculate within-field statistical variation of four crop variables: shoot dry weight (SDW), shoot N concentration (SN), shoot N density (SND) and N nutrition index (NNI) using measured canopy reflectance data from a field of 6,500 m2 in 2004. Results showed that PLS regression using logarithm reflectance had better performance than both the PLS and multiple stepwise linear regression (MSLR) models using original reflectance data to calculate the four plant variables in year 2000 and 2003. It produced values with an acceptable model coefficient of determination (R 2) and relative error of calculation (REC). The model R 2 and REC ranged from .83 to .89 and 13.4% to 22.8% for calibration, and .76 to .87 and 14.0% to 24.4% for validation, respectively. The PLS regression model R 2 was reduced in the test data of year 2004 but the root mean square error of calculation (RMSEC) was smaller, suggesting that the PLS regression model using canopy reflectance data could be a promising method to calculate within-field spatial variation of rice crop growth and N status.
Histone methylation plays an important role in regulating gene expression. One such methylation o... more Histone methylation plays an important role in regulating gene expression. One such methylation occurs at Lys 79 of histone H3 (H3K79) and is catalyzed by the yeast DOT1 (disruptor of telomeric silencing) and its mammalian homolog, DOT1L. Previous studies have demonstrated that germline disruption of Dot1L in mice resulted in embryonic lethality. Here we report that cardiac-specific knockout of Dot1L results in increased mortality rate with chamber dilation, increased cardiomyocyte cell death, systolic dysfunction, and conduction abnormalities. These phenotypes mimic those exhibited in patients with dilated cardiomyopathy (DCM). Mechanistic studies reveal that DOT1L performs its function in cardiomyocytes through regulating Dystrophin (Dmd) transcription and, consequently, stability of the Dystrophin-glycoprotein complex important for cardiomyocyte viability. Importantly, expression of a miniDmd can largely rescue the DCM phenotypes, indicating that Dmd is a major target mediating DOT1L function in cardiomyocytes. Interestingly, analysis of available gene expression data sets indicates that DOT1L is down-regulated in idiopathic DCM patient samples compared with normal controls. Therefore, our study not only establishes a critical role for DOT1L-mediated H3K79 methylation in cardiomyocyte function, but also reveals the mechanism underlying the role of DOT1L in DCM. In addition, our study may open new avenues for the diagnosis and treatment of human heart disease.
Chromosomal translocations of the mixed lineage leukemia (MLL) gene are a common cause of acute l... more Chromosomal translocations of the mixed lineage leukemia (MLL) gene are a common cause of acute leukemias. The oncogenic function of MLL fusion proteins is, in part, mediated through aberrant activation of Hoxa genes and Meis1, among others. Here we demonstrate using a tamoxifen-inducible Cre-mediated loss of function mouse model that DOT1L, an H3K79 methyltransferase, is required for both initiation and maintenance of MLL-AF9-induced leukemogenesis in vitro and in vivo. Through gene expression and chromatin immunoprecipitation analysis we demonstrate that mistargeting of DOT1L, subsequent H3K79 methylation, and up-regulation of Hoxa and Meis1 genes underlie the molecular mechanism of how DOT1L contributes to MLL-AF9-mediated leukemogenesis. Our study not only provides the first in vivo evidence for the function of DOT1L in leukemia, but also reveals the molecular mechanism for DOT1L in MLL-AF9 mediated leukemia. Thus, DOT1L may serve as a potential therapeutic target for the treatment of leukemia caused by MLL translocations.
DOT1 (disruptor of telomeric silencing; also called Kmt4) was initially discovered in budding yea... more DOT1 (disruptor of telomeric silencing; also called Kmt4) was initially discovered in budding yeast in a genetic screen for genes whose deletion confers defects in telomeric silencing. Since the discovery ∼10 years ago that Dot1 and its mammalian homolog, DOT1L (DOT1-Like), possess histone methyltransferase activity toward histone H3 Lys 79, great progress has been made in characterizing their enzymatic activities and the role of Dot1/DOT1L-mediated H3K79 methylation in transcriptional regulation, cell cycle regulation, and the DNA damage response. In addition, gene disruption in mice has revealed that mouse DOT1L plays an essential role in embryonic development, hematopoiesis, cardiac function, and the development of leukemia. The involvement of DOT1L enzymatic activity in leukemogenesis driven by a subset of MLL (mixed-lineage leukemia) fusion proteins raises the possibility of targeting DOT1L for therapeutic intervention.
This study was aimed at determining the molecular epidemiology of rabies virus (RABV) circulating... more This study was aimed at determining the molecular epidemiology of rabies virus (RABV) circulating in Vietnam. Intra vitam samples (saliva and cerebrospinal fluid) were collected from 31 patients who were believed to have rabies and were admitted to hospitals in northern provinces of Vietnam. Brain samples were collected from 176 sick or furious rabid dogs from all over the country. The human and canine samples were subjected to reverse transcription-polymerase chain reaction analysis. The findings showed that 23 patients tested positive for RABV. Interestingly, 5 rabies patients did not have any history of dog or cat bites, but they had an experience of butchering dogs or cats, or consuming their meat. RABV was also detected in 2 of the 100 sick dogs from slaughterhouses. Molecular epidemiological analysis of 27 RABV strains showed that these viruses could be classified into two groups. The RABVs classified into Group 1 were distributed throughout Vietnam and had sequence similarity with the strains from China, Thailand, Malaysia, and the Philippines. However, the RABVs classified into Group 2 were only found in the northern provinces of Vietnam and showed high sequence similarity with the strain from southern China. This finding suggested the recent influx of Group 2 RABVs between Vietnam and China across the border. Although the incidence of rabies due to circulating RABVs in slaughterhouses is less common than that due to dog bite, the national program for rabies control and prevention in Vietnam should include monitoring of the health of dogs meant for human consumption and vaccination for workers at dog slaughterhouses. Further, monitoring of and research on the circulating RABVs in dog markets may help to determine the cause of rabies and control the spread of rabies in slaughterhouses in Vietnam.
Bacterial degradation of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) has been previously r... more Bacterial degradation of 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) has been previously reported, however, its degradation enzyme system has not been characterized. In this study, a DDEdegrading bacterium, Janibacter sp. TYM3221, was isolated and characterized. Transformation of DDE was demonstrated by TYM3211 resting cells grown in LB in the presence and absence of biphenyl. Gas chromatography-mass spectrometry analysis revealed five metabolites of DDE containing a meta-ring cleavage product and 4-chlorobenzoic acid, suggesting that TYM3221 degrades DDE to 4-chlorobenzoic acid via a meta-ring cleavage product. A gene cluster, bphAaAbAcAd, which codes for biphenyl dioxygenase subunits, was cloned from TYM3221. A mutant strain with a bphAa-gene inactivation did not grow on biphenyl, and showed no DDE degradation activity. These results indicate that in strain TYM3221, the bphAa-coded biphenyl dioxygenase is involved not only in the metabolism of biphenyl but also in the degradation of DDE.
Previously three oncogene transgenic zebrafish lines with inducible expression of xmrk, kras or M... more Previously three oncogene transgenic zebrafish lines with inducible expression of xmrk, kras or Myc in the liver have been generated and these transgenic lines develop oncogene-addicted liver tumors upon chemical induction. In the current study, comparative transcriptomic approaches were used to examine the correlation of the three induced transgenic liver cancers with human liver cancers. RNA profiles from the three zebrafish tumors indicated relatively small overlaps of significantly deregulated genes and biological pathways. Nevertheless, the three transgenic tumor signatures all showed significant correlation with advanced or very advanced human hepatocellular carcinoma (HCC). Interestingly, molecular signature from each oncogene-induced zebrafish liver tumor correlated with only a small subset of human HCC samples (24-29%) and there were conserved up-regulated pathways between the zebrafish and correlated human HCC subgroup. The three zebrafish liver cancer models together represented nearly half (47.2%) of human HCCs while some human HCCs showed significant correlation with more than one signature defined from the three oncogene-addicted zebrafish tumors. In contrast, commonly deregulated genes (21 up and 16 down) in the three zebrafish tumor models generally showed accordant deregulation in the majority of human HCCs, suggesting that these genes might be more consistently deregulated in a broad range of human HCCs with different molecular mechanisms and thus serve as common diagnosis markers and therapeutic targets. Thus, these transgenic zebrafish models with well-defined oncogene-induced tumors are valuable tools for molecular classification of human HCCs and for understanding of molecular drivers in hepatocarcinogenesis in each human HCC subgroup.
Hepatocellular carcinoma (HCC) is currently one of the top lethal cancers with an increasing tren... more Hepatocellular carcinoma (HCC) is currently one of the top lethal cancers with an increasing trend. Deregulation of MYC in HCC is frequently detected and always correlated with poor prognosis. As the zebrafish genome contains two differentially expressed zebrafish myc orthologs, myca and mycb, it remains unclear about the oncogenicity of the two zebrafish myc genes. In the present study, we developed two transgenic zebrafish lines to overexpress myca and mycb respectively in the liver using a mifepristone-inducible system and found that both myc genes were oncogenic. Moreover, the transgenic expression of myca in hepatocytes caused robust liver tumors with several distinct phenotypes of variable severity.~5% of myca transgenic fish developing multinodular HCC with cirrhosis after 8 months of induced myca expression. Apoptosis was also observed with myca expression; introduction of homozygous tp53 -/mutation into the myca transgenic fish reduced apoptosis and accelerated tumor progression. The malignant status of hepatocytes was dependent on continued expression of myca; withdrawal of the mifepristone inducer resulted in a rapid regression of liver tumors, and the tumor regression occurred even in the tp53 -/mutation background. Thus, our data demonstrated the robust oncogenicity of zebrafish myca and the requirement of sustained Myc overexpression for maintenance of the liver tumor phenotype in this transgenic model. Furthermore, tumor regression is independent of the function of Tp53.
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