[Show abstract][Hide abstract] ABSTRACT: Genetic markers associated with disease are often non-functional and generally tag one or more functional "causative" variants in linkage disequilibrium. Markers may not show tight linkage to the causative variants across multiple ethnicities due to evolutionary divergence, and therefore may not be informative across different population groups. Validated markers of disease suggest causative variants exist in the gene and, if the causative variants can be identified, it is reasonable to hypothesize that such variants will be informative across diverse populations. The aim of this study was to test that hypothesis using functional Interleukin-1 (IL-1) gene variations across multiple ethnic populations to replace the non-functional markers originally associated with chronic adult periodontitis in Caucasians.
Adult chronic periodontitis cases and controls from four ethnic groups (Caucasians, African Americans, Hispanics and Asians) were recruited in the USA, Chile and China. Genotypes of IL1B gene single nucleotide polymorphisms (SNPs), including three functional SNPs (rs16944, rs1143623, rs4848306) in the promoter and one intronic SNP (rs1143633), were determined using a single base extension method or TaqMan 5' nuclease assay. Logistic regression and other statistical analyses were used to examine the association between moderate to severe periodontitis and IL1B gene variations, including SNPs, haplotypes and composite genotypes. Genotype patterns associated with disease in the discovery study were then evaluated in independent validation studies.
Significant associations were identified in the discovery study, consisting of Caucasians and African Americans, between moderate to severe adult chronic periodontitis and functional variations in the IL1B gene, including a pattern of four IL1B SNPs (OR = 1.87, p < 0.0001). The association between the disease and this IL1B composite genotype pattern was validated in two additional studies consisting of Hispanics (OR = 1.95, p = 0.04) or Asians (OR = 3.27, p = 0.01). A meta-analysis of the three populations supported the association between the IL-1 genotype pattern and moderate to severe periodontitis (OR 1.95; p < 0.001). Our analysis also demonstrated that IL1B gene variations had added value to conventional risk factors in predicting chronic periodontitis.
This study validated the influence of IL-1 genetic factors on the severity of chronic periodontitis in four different ethnicities.
Full-text · Article · Apr 2014 · Journal of Periodontal Research
[Show abstract][Hide abstract] ABSTRACT: Low temperature metamorphic indicators were used to investigate the tectonothermal evolution of the Triassic flysch in the Songpan–Garzê orogen, eastern margin of the Tibetan plateau. Iso-thermal zones mapped with illite crystallinity (Kübler index, KI) describe a complex pattern of the diagenetic, anchimetamorphic and epimetamorphic zones. From this pattern, a general increase in grade toward the Longmenshan fault belt is observed, and across the Longmenshan fault belt, greenschist facies and anchizonal rocks on its NW side are juxtaposed to diagenetic rocks in the Sichuan basin on its SE side. This juxtaposition is marked by KI jumps of 0.23°Δ2θ in the SW portion of the Longmenshan fault through 0.39°Δ2θ in the Middle, and reaching 0.71°Δ2θ in the NE of the Longmenshan fault thus describing a clockwise rotation of the upper part of the Longmenshan fault after metamorphism. Across the Xianshuihe fault, the truncated KI zones within the Triassic flysch suggest a total offset of roughly 50–60 km due to post-metamorphic sinistral strike-slip. Peak metamorphic conditions are estimated at 365–431 °C with a pressure facies of low to intermediate type (3 kbar).
Compression at the end of the Triassic was induced by the interaction of the South China, North China and North Tibetan blocks, which caused the closure of the Paleo-Tethys Ocean and led to the folding of the Triassic flysch within the Songpan–Garzê basin. Very low to low grade metamorphism was caused by crustal thickening due to an accretionary wedge setting, which led to an increase in the thickness of the Triassic flysch to > 10 km, and resulted in a temperature increase in those rocks due to burial. Finally, the Indo-Asia collision caused the formation of the Longmenshan and the Xianshuihe strike-slip faults in the early Tertiary and disturbed the distribution of the metamorphic zones.
[Show abstract][Hide abstract] ABSTRACT: This study investigated the effect and mechanism of Astragalus polysaccharides (APS) on chronic atrophic gastritis (CAG) induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in rats. Histomorphological, hormone-level, and immunohistochemistry experiments were used to investigate the gastric mucosal injury. Pathological changes were readily found in CAG rats. Compared to the control rats, the CAG rats showed significantly decreased plasma levels of gastrin and somatostatin while their motilin levels increased. Moreover, PGE2 in gastric tissue increased and serum sIgA decreased significantly, while the GSH/GSSG ratio showed no change. Immunohistochemical detection showed that the expression of EGFR, COX-2, and MMP-2 was higher in the gastric tissue of CAG rats. After APS treatment, the gastric morphology of CAG rats improved. APS increased plasma gastrin and somatostatin levels significantly but had no significant effect on the motilin level. APS also decreased tissue PGE2 and increased serum sIgA in CAG rats without affecting the GSH/GSSH ratio. This study suggested that APS had a beneficial effect on CAG rats by deregulating EGFR at its downstream effectors COX-2 and MMP-2.
[Show abstract][Hide abstract] ABSTRACT: In this work, we present a short review of the recent development of the theoretical models for top-hat cw laser induced spectroscopies of thermal lens and thermal mirror. With the same probe and top-hat excitation lasers, an apparatus is set up to concurrently measure both thermal lens and thermal mirror effects of transparent samples. With the theoretical models and the experimental apparatus, not only optical and thermal properties are measured, but also the fluorescence quantum coefficient and the temperature coefficient of the optical path length of a fluorescent sample are simultaneously determined with no need of any reference sample. Mechanical properties also could be measured. Opaque samples are also studied using top-hat cw laser thermal mirror and top-hat photothermal deflection techniques to determine thermal properties (e.g., thermal conductivity and unit volume specific heat). This work shows that the combined top-hat cw laser photothermal techniques are useful for nondestructive evaluation of both transparent and opaque samples with a less expensive non-TEM00 Gaussian laser.
Full-text · Article · Apr 2010 · Journal of Physics Conference Series
[Show abstract][Hide abstract] ABSTRACT: Considering the time dependence of the absorption coefficient due to the photo-induced chemical reaction (PCR) and species diffusion, we calculate the temperature rise in the thermal lens (TL) effect and the TL signal at the detector plane. This theoretical approach removes the restriction that the PCR time constant is much greater than the characteristic TL time constant, which was assumed in a previously published model. Aqueous Cr(VI)-diphenylcarbazide solution is investigated, and quantitative experimental results for the thermal, optical and PCR properties of the sample are obtained. The relative difference between the parameters extracted from the same experimental data of the Cr(VI) solution using the previous and present models is found to be less than 5%, showing the present model can be used to study the PCR. Moreover the present model is more general than the previous one.
No preview · Article · Apr 2010 · Journal of Physics Conference Series
[Show abstract][Hide abstract] ABSTRACT: In this work, an in-house made Loschmidt diffusion cell is used to measure the effective O(2)-N(2) diffusion coefficients through four porous samples of different simple pore structures. One-dimensional through-plane mass diffusion theory is applied to process the experimental data. It is found that both bulk diffusion coefficient and the effective gas diffusion coefficients of the samples can then be precisely determined, and the measured bulk one is in good agreement with the literature value. Numerical computation of three-dimensional mass diffusion through the samples is performed to calculate the effective gas diffusion coefficients. The comparison between the measured and calculated coefficient values shows that if the gas diffusion through a sample is dominated by one-dimensional diffusion, which is determined by the pore structure of the sample, these two values are consistent, and the sample can be used as a standard sample to test a gas diffusion measurement system.
Full-text · Article · Apr 2010 · The Review of scientific instruments
[Show abstract][Hide abstract] ABSTRACT: Cited By (since 1996): 1, Export Date: 18 July 2012, Source: Scopus, Art. No.: 012014, doi: 10.1088/1742-6596/214/1/012014, Language of Original Document: English, Correspondence Address: Shen, J.; National Research Council of Canada, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5, Canada; email: Jun.Shen@nrc-cnrc.gc.ca, References: Mandelis, A., (1991) Progress in Photoacoustic and Photothermal Science and Technology, , New York: Elsevier;
No preview · Article · Jan 2010 · Journal of Physics Conference Series
[Show abstract][Hide abstract] ABSTRACT: Export Date: 18 July 2012, Source: Scopus, Art. No.: 012125, doi: 10.1088/1742-6596/214/1/012125, Language of Original Document: English, Correspondence Address: Astrath, N. G. C.; National Research Council Canada, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5, Canada; email: AstrathNGC@pq.cnpq.br, References: Bialkowski, S.E., (1996) Photothermal Spectroscopy Methods for Chemical Analysis, , Wiley, New York;
Full-text · Article · Jan 2010 · Journal of Physics Conference Series
[Show abstract][Hide abstract] ABSTRACT: In this work, a composite photothermal technique combining open photoacoustic cell and photothermal deflection methods for thermal characterization of opaque solids was developed. An excitation laser was employed to concurrently generate both photoacoustic and mirage effects. Thermal diffusivity and thermal effusivity of carbon-based samples were measured, and the values of thermal conductivities and specific heat were then deduced. The experimental results were found to be in good agreement with the literature values. The photothermal technique developed in this work permits a convenient and precise measurement of thermal properties of solids.
No preview · Article · Oct 2008 · Journal of Applied Physics
[Show abstract][Hide abstract] ABSTRACT: A complete theoretical model is presented for the thermal mirror technique under top-hat laser excitation. Considering the
attenuation of the top-hat excitation laser intensity along the thickness of a sample due to its optical absorption coefficient,
we calculate the laser-induced temperature and surface deformation profiles. Asimplified theoretical model for a high absorption
sample is also developed. The center intensity of a probe beam reflected from the thermal mirror at a detector plane is derived.
Numerical simulation shows that the thermal mirror under the top-hat laser excitation is as sensitive as that under Gaussian
laser excitation. With top-hat laser excitation, the experimental results of thermo-physical properties of opaque samples
are found to be well consistent with literature values, validating the theory.
Full-text · Article · Mar 2008 · Applied Physics B
[Show abstract][Hide abstract] ABSTRACT: In this work, an effective gas diffusion coefficient of a
porous medium was measured using photothermal deflection (PD) technique. An
in-house made Loschmidt diffusion cell with a photothermal-deflection probe
were employed to measure the effective gas diffusion coefficient of a gas
diffusion layer (GDL) with a porosity ε ≈ 0.7. The concentration
evolutions of CO2 in O2 with and without the GDL were measured,
respectively, using a transverse normal PD technique. The concentration
variations were used to deduce the gas diffusion coefficients in the
presence and absence of the GDL by solving mass diffusion equations. The
effective gas diffusion coefficient of the GDL was calculated from the
diffusion coefficients using a model of an equivalent resistance to
diffusion and found to be 4.39 × 10-6 m2s-1,
demonstrating that PD technique can be employed to determine the effective
gas diffusion coefficient of a porous medium.
Full-text · Article · Dec 2007 · The European Physical Journal Special Topics
[Show abstract][Hide abstract] ABSTRACT: The application of recently developed diffraction theory
for cw transverse photothermal deflection spectroscopy (normal deflection
only) to the measurements of thermophysical and mass-diffusion properties of
gases is presented. Compared with the traditional ray-optics theory, the
diffraction theory has one more term in the phase signal. This term
quantitatively exhibits the probe-beam size effect on the phase signal.
Experimental results demonstrated that even if the ratio of the probe-beam
radius to the thermal diffusion length of a deflecting medium was as low as
about 0.22, the probe-beam size effect could not be ignored when measuring
the distance between the probe beam and a solid sample using the phase
signal. With the measured distance, the thermal diffusivity αg and the
temperature coefficient of the refractive index dn/dT of pure gases (O2,
N2, and CO2) and binary gas mixtures (CO2-O2 and
CO2-O2) were precisely measured, resulting in good agreement with
literature values. Furthermore the measured dn/dT values of the pure gases had
one more significant figure than the literature ones. The concentration
dependences of αg and dn/dT were employed for the determination of
mass-diffusion coefficients of CO2-O2 and CO2-N2, and
the results were consistent with literature values.
No preview · Article · Dec 2007 · The European Physical Journal Special Topics
[Show abstract][Hide abstract] ABSTRACT: A photothermal deflection (PD) technique was applied to measure the binary diffusion coefficients of various gases (CO2–N2, CO2–O2, N2–He, O2–He, and CO2–He). With an in-house-made Loschmidt diffusion cell, a transverse PD system was employed to measure the time-resolved PD
signal associated with the variation of the thermal diffusivity and the temperature coefficient of the refractive index of
the gas mixture during the diffusion. The concentration evolution of the gas mixture was deduced from the PD amplitude and
phase signals based on our diffraction PD model and was processed using two mass-diffusion models explored in this work for
both short- and long-time diffusions to find the diffusion coefficient. An optical fiber oxygen sensor was also used to measure
the concentration changes of the mixtures with oxygen. Experimental results demonstrated that the binary diffusion coefficients
precisely measured with the PD technique were in agreement with the literature values. Moreover, the PD technique can measure
the diffusion coefficients of various gas mixtures with both short- and long-time diffusions. In contrast, the oxygen sensor
is only suitable for the long-time diffusion measurements of the gas mixtures with oxygen.
No preview · Article · Mar 2007 · Applied Physics B
[Show abstract][Hide abstract] ABSTRACT: Thermal properties of solid samples have been measured using recently developed time-resolved photothermal deflection spectrometry with step optical excitation. Thermal diffusivity can be measured directly, and thermal effusivity may be obtained by using a reference sample. Consequently, the thermal conductivity and the unit volume specific heat of a sample can be deduced from the measured thermal diffusivity and effusivity. The experimental results are in good agreement with literature values, indicating the time-resolved photothermal deflection spectrometry with step optical excitation is a very rigorous method in measuring thermophysical properties of solid materials.
No preview · Article · Jun 2005 · Journal de Physique IV (Proceedings)
[Show abstract][Hide abstract] ABSTRACT: Most conventional air heaters adopt indirect heat transfer, which uses combustion gases to indirectly heat fresh air by heating surfaces to generate hot air used for material drying and dehumidification. We call them indirect air heaters. However, they have a higher manufacturing cost and lower thermal efficiency, especially when high temperature air is needed. For this reason, a direct air heater applicable for or feed and industrial raw products is put forward, which has advantages such as less production cost, smaller dimensions and higher thermal efficiency. Their design, working principles, characteristics, structure and applications are presented in this article, and brief comparisons are made between the indirect and direct air heater. Finally, the relation of hot-air temperature, oil or gas consumption and fresh airflow is determined based on energy equilibrium.