An association between Candida and oral cancer has long been discussed in the literature and in particular Candida albicans has been proposed to play a significant role in the development of oral cancer. Although this...An association between Candida and oral cancer has long been discussed in the literature and in particular Candida albicans has been proposed to play a significant role in the development of oral cancer. Although this organism is a common member of the oral mucosa and can cause a variety of oral mucosal lesions, the exact mechanisms by which C. albicans potentially causes the development of malignant disease still require much research. We have undertaken an extensive literature search to understand pathogenicity of C. albicans, including its virulence factors, its interactions with the host immune, how a dysregulation of the immune response can result in malignancy, and how a potential C. albicans specific cytokine response may be involved in oral carcinogenesis. We present here a candid assessment of the role of Candida in oral carcinogenesis and a hypothetical model about how this may occur. Finally, we present potential future research which is necessary to elucidate this role.展开更多
Thermally grown surface oxide layers dominate the single-asperity tribological behavior of a Zr60Cu30Al10 glass.Increase in oxidation time leads to an increased contribution of shearing and a corresponding decreased c...Thermally grown surface oxide layers dominate the single-asperity tribological behavior of a Zr60Cu30Al10 glass.Increase in oxidation time leads to an increased contribution of shearing and a corresponding decreased contribution of ploughing to friction.This change in the dominating friction and wear mechanism results in an overall minor decrease of the friction coefficient of oxidized surfaces compared to the metallic glass sample with native surface oxide.Our results demonstrate the importance of creating a stable oxide layer for practical applications of metallic glasses in micro-devices involving sliding contact.展开更多
A 3D lattice Boltzmann(LB)model with twenty-seven discrete velocities is presented and used for the simulation of three-dimensional porous media flows.Its accuracy in combination with the half-way bounce back boundary...A 3D lattice Boltzmann(LB)model with twenty-seven discrete velocities is presented and used for the simulation of three-dimensional porous media flows.Its accuracy in combination with the half-way bounce back boundary condition is assessed.Characteristic properties of the gas diffusion layers that are used in polymer electrolyte fuel cells can be determined with this model.Simulation in samples that have been obtained via X-ray tomographic microscopy,allows to estimate the values of permeability and relative effective diffusivity.Furthermore,the computational LB results are compared with the results of other numerical tools,as well as with experimental values.展开更多
The demand for spectacle independence at all ages continues to grow,as our population ages and life expectancy continues to rise.Younger and older individuals alike expect greater freedom to pursue their active lifest...The demand for spectacle independence at all ages continues to grow,as our population ages and life expectancy continues to rise.Younger and older individuals alike expect greater freedom to pursue their active lifestyles.However,as demands for higher levels of visual function increase,ophthalmologists have more technological options for refractive corrections than ever before,making it more important for surgeons to employ the most up to date methods and technology to fulfill patients’ever rising expectations of precise visual outcomes.展开更多
We examined the genetic diversity on a microgeographic scale of <em>Rhinichthys atratulus</em> (Eastern Blacknose Dace) in Allyn Brook, a small tributary in the upper Coginchaug River drainage in Connectic...We examined the genetic diversity on a microgeographic scale of <em>Rhinichthys atratulus</em> (Eastern Blacknose Dace) in Allyn Brook, a small tributary in the upper Coginchaug River drainage in Connecticut. By looking at gene flow on a microgeographic scale among populations that had no physical barriers to migration, we tested the null hypothesis that the populations should be homogeneous. We resolved seven polymorphic microsatellite loci and one mitochondrial gene, <em>nd</em>2, in three adjacent populations (<0.5 km) in Allyn Brook and compared these populations to the two closest populations (>5 km) in the Coginchaug River. A dam from the 1920’s in lower Allyn Brook has isolated Allyn-Brook populations from Coginchaug-River populations. Allyn Brook was selected because there are only three riffle habitats in the brook and, therefore, there can be no immigration from upstream populations. Each population has private (<em>i.e</em>., unique) alleles and haplotypes, and there are significant genetic differences between all sites. The Allyn Brook populations are almost as different from one another as they are from the distant populations in the Coginchaug River from which they have been isolated for more than 80 years. These results point to <em>in situ</em> evolution and little migration or gene flow among populations on a microgeographic scale. This raises interesting questions for conservation of genetic diversity of stream fishes.展开更多
Large-scale virtual scene exploration is still a challenging task. The novice users caneasily get distracted and disorientated, which results in being lost in space. Assistedcamera control technology is the most effec...Large-scale virtual scene exploration is still a challenging task. The novice users caneasily get distracted and disorientated, which results in being lost in space. Assistedcamera control technology is the most effective solution for virtual environment exploration problems which requires viewpoint computation and path planning. In this paper,a novel approach for large-scale virtual scene based on viewpoint scoring is proposed.First, the scene was adaptively divided into several meaningful and easily analyzedsubregions according to the optimal view distance criterion. Second, a novel viewpointscoring method based on visual perception and information entropy fusion was developed for optimal viewpoint determination and greedy N-Best viewpoint selection algorithm was utilized for visual perceptibility calculation. Then evolutionary programmingapproach for the Traveling Salesman problem was applied for intra-subregion and intersubregion exploring path optimization. Finally, the Cubic Hermite Curve was introduced to smoothen the inflection point on the exploration path. The experimental resultsdemonstrate that the proposed method can effectively generate an automatic smooth,informative, aesthetic and non-intersecting path, with the characteristics of good exploring comfort, strong immersion and high scene information perception.展开更多
目的探讨源于钆塞酸增强MRI的肝细胞摄取率是否与肝功能的定量测量有关,并帮助识别大范围肝切除术的禁忌证。材料与方法在2016年8月—2016年10月期间,纳入50例患有慢性肝病或肝硬化的受试者进行3.0 T MRI肝脏检查,包括T1 mapping和弹性...目的探讨源于钆塞酸增强MRI的肝细胞摄取率是否与肝功能的定量测量有关,并帮助识别大范围肝切除术的禁忌证。材料与方法在2016年8月—2016年10月期间,纳入50例患有慢性肝病或肝硬化的受试者进行3.0 T MRI肝脏检查,包括T1 mapping和弹性成像。展开更多
We report on an ultrafast nonequilibrium phase transition with a strikingly long-lived martensitic anomaly driven by above-threshold single-cycle terahertz pulses with a peak field of more than 1 MV/cm.A nonthermal,te...We report on an ultrafast nonequilibrium phase transition with a strikingly long-lived martensitic anomaly driven by above-threshold single-cycle terahertz pulses with a peak field of more than 1 MV/cm.A nonthermal,terahertz-induced depletion of low-frequency conductivity in Nb_(3)Sn indicates increased gap splitting of high-energy Г_(12) bands by removal of their degeneracies,which induces the martensitic phase above their equilibrium transition temperature.In contrast,optical pumping leads to a Г_(12) gap thermal melting.Such light-induced nonequilibrium martensitic phase exhibits a substantially enhanced critical temperature up to~100 K,i.e.,more than twice the equilibrium temperature,and can be stabilized beyond technologically relevant,nanosecond time scales.Together with first-principle simulations,we identify a compelling terahertz tuning mechanism of structural order via Г_(12) phonons to achieve the ultrafast phase transition to a metastable electronic state out of equilibrium at high temperatures far exceeding those for equilibrium states.展开更多
A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidified at different degrees of undercooling. It is found that the metastable Co23B6 phase solidifies as a substitut...A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidified at different degrees of undercooling. It is found that the metastable Co23B6 phase solidifies as a substitute for the stable Co3 B phase in the alloy melts undercooled above a critical undercooling value of -60 K.The Co23B6 and α-Co phases make up a metastable eutectic. The corresponding eutectic composition and temperature are Co80.4B19.6 and 1343 K, respectively. On exposure of the metastable Co23B6 phase at a given temperature above 1208 K, it does not decompose even after several hours. But it transforms by a eutectoid reaction to α-Co ＋ Co3 B at lower temperature.展开更多
Single longitudinal mode continuous-wave operation of GaN-based distributed Bragg reflector(DBR) laser diodes with 10 th-order surface gratings is demonstrated. The DBR consists of periodic V-shaped grooves on a 2 μm...Single longitudinal mode continuous-wave operation of GaN-based distributed Bragg reflector(DBR) laser diodes with 10 th-order surface gratings is demonstrated. The DBR consists of periodic V-shaped grooves on a 2 μm wide ridge waveguide fabricated by using electron-beam lithography and plasma etching. The effect of different lengths of the DBR section and the gain section on the device performance has been studied. Periodic mode hops to the adjacent longitudinal Fabry–Perot resonator mode at shorter wavelength have been observed when increasing the operation current. Between the mode hops, single longitudinal mode emission at around 405 nm is achieved with a full width at half-maximum of 0.03 nm. A linear redshift of the emission wavelength with increasing temperature of 0.019 nm/K was derived.展开更多
The material and electrical properties of HfO 2 hi gh-k gate dielectric are reported.In the first part,the band alignment of H fO 2 and (HfO 2) x(Al 2O 3) 1-x to (100)Si substrate and thei r thermal stability are stud...The material and electrical properties of HfO 2 hi gh-k gate dielectric are reported.In the first part,the band alignment of H fO 2 and (HfO 2) x(Al 2O 3) 1-x to (100)Si substrate and thei r thermal stability are studied by X-ray photoelectron spectroscopy and TEM.The energy gap of (HfO 2) x(Al 2O 3) 1-x,the valence band offset, and the conduction band offset between (HfO 2) x(Al 2O 3) 1-x and the Si substrate as functions of x are obtained based on the XPS results .Our XPS results also demonstrate that both the thermal stability and the resist ance to oxygen diffusion of HfO 2 are improved by adding Al to form Hf aluminat es.In the second part,a thermally stable and high quality HfN/HfO 2 gate stack is reported.Negligible changes in equivalent oxide thickness (EOT),gate leakage, and work function (close to Si mid-gap) of HfN/HfO 2 gate stack are demonstrat ed even after 1000℃ post-metal annealing(PMA),which is attributed to the super ior oxygen diffusion barrier of HfN as well as the thermal stability of the HfN/ HfO 2 interface.Therefore,even without surface nitridation prior to HfO 2 depo sition,the EOT of HfN/HfO 2 gate stack has been successfully scaled down to les s than 1nm after 1000℃ PMA with excellent leakage and long-term reliability.T he last part demonstrates a novel replacement gate process employing a HfN dummy gate and sub-1nm EOT HfO 2 gate dielectric.The excellent thermal stability of the HfN/HfO 2 gate stack enables its use in high temperature CMOS processes.Th e replacement of HfN with other metal gate materials with work functions adequat e for n- and p-MOS is facilitated by a high etch selectivity of HfN with respe ct to HfO 2,without any degradation to the EOT,gate leakage,or TDDB characteris tics of HfO 2.展开更多
文摘An association between Candida and oral cancer has long been discussed in the literature and in particular Candida albicans has been proposed to play a significant role in the development of oral cancer. Although this organism is a common member of the oral mucosa and can cause a variety of oral mucosal lesions, the exact mechanisms by which C. albicans potentially causes the development of malignant disease still require much research. We have undertaken an extensive literature search to understand pathogenicity of C. albicans, including its virulence factors, its interactions with the host immune, how a dysregulation of the immune response can result in malignancy, and how a potential C. albicans specific cytokine response may be involved in oral carcinogenesis. We present here a candid assessment of the role of Candida in oral carcinogenesis and a hypothetical model about how this may occur. Finally, we present potential future research which is necessary to elucidate this role.
文摘Thermally grown surface oxide layers dominate the single-asperity tribological behavior of a Zr60Cu30Al10 glass.Increase in oxidation time leads to an increased contribution of shearing and a corresponding decreased contribution of ploughing to friction.This change in the dominating friction and wear mechanism results in an overall minor decrease of the friction coefficient of oxidized surfaces compared to the metallic glass sample with native surface oxide.Our results demonstrate the importance of creating a stable oxide layer for practical applications of metallic glasses in micro-devices involving sliding contact.
基金Financial support from BFE via projects 103078 and 153708 is kindly acknowledgedpartial support from KTH Mechanics.
文摘A 3D lattice Boltzmann(LB)model with twenty-seven discrete velocities is presented and used for the simulation of three-dimensional porous media flows.Its accuracy in combination with the half-way bounce back boundary condition is assessed.Characteristic properties of the gas diffusion layers that are used in polymer electrolyte fuel cells can be determined with this model.Simulation in samples that have been obtained via X-ray tomographic microscopy,allows to estimate the values of permeability and relative effective diffusivity.Furthermore,the computational LB results are compared with the results of other numerical tools,as well as with experimental values.
基金The workis supported in part by DOE EPSCoR Program under contracts DE-FG02-01ER45899the Office of Fossil Energy,Advanced Research Materials ( ARM)Program,DOE,under contract DE-AC05-00OR22725 managed by UT-Battelle, LLC
文摘The demand for spectacle independence at all ages continues to grow,as our population ages and life expectancy continues to rise.Younger and older individuals alike expect greater freedom to pursue their active lifestyles.However,as demands for higher levels of visual function increase,ophthalmologists have more technological options for refractive corrections than ever before,making it more important for surgeons to employ the most up to date methods and technology to fulfill patients’ever rising expectations of precise visual outcomes.
文摘We examined the genetic diversity on a microgeographic scale of <em>Rhinichthys atratulus</em> (Eastern Blacknose Dace) in Allyn Brook, a small tributary in the upper Coginchaug River drainage in Connecticut. By looking at gene flow on a microgeographic scale among populations that had no physical barriers to migration, we tested the null hypothesis that the populations should be homogeneous. We resolved seven polymorphic microsatellite loci and one mitochondrial gene, <em>nd</em>2, in three adjacent populations (<0.5 km) in Allyn Brook and compared these populations to the two closest populations (>5 km) in the Coginchaug River. A dam from the 1920’s in lower Allyn Brook has isolated Allyn-Brook populations from Coginchaug-River populations. Allyn Brook was selected because there are only three riffle habitats in the brook and, therefore, there can be no immigration from upstream populations. Each population has private (<em>i.e</em>., unique) alleles and haplotypes, and there are significant genetic differences between all sites. The Allyn Brook populations are almost as different from one another as they are from the distant populations in the Coginchaug River from which they have been isolated for more than 80 years. These results point to <em>in situ</em> evolution and little migration or gene flow among populations on a microgeographic scale. This raises interesting questions for conservation of genetic diversity of stream fishes.
文摘Large-scale virtual scene exploration is still a challenging task. The novice users caneasily get distracted and disorientated, which results in being lost in space. Assistedcamera control technology is the most effective solution for virtual environment exploration problems which requires viewpoint computation and path planning. In this paper,a novel approach for large-scale virtual scene based on viewpoint scoring is proposed.First, the scene was adaptively divided into several meaningful and easily analyzedsubregions according to the optimal view distance criterion. Second, a novel viewpointscoring method based on visual perception and information entropy fusion was developed for optimal viewpoint determination and greedy N-Best viewpoint selection algorithm was utilized for visual perceptibility calculation. Then evolutionary programmingapproach for the Traveling Salesman problem was applied for intra-subregion and intersubregion exploring path optimization. Finally, the Cubic Hermite Curve was introduced to smoothen the inflection point on the exploration path. The experimental resultsdemonstrate that the proposed method can effectively generate an automatic smooth,informative, aesthetic and non-intersecting path, with the characteristics of good exploring comfort, strong immersion and high scene information perception.
基金supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Science and Engineering Division under contract no.DEAC02-07CH11358(scientific drive,THz spectroscopy characterization of Martensitic phase,and theoretical prediction and analysis).
文摘We report on an ultrafast nonequilibrium phase transition with a strikingly long-lived martensitic anomaly driven by above-threshold single-cycle terahertz pulses with a peak field of more than 1 MV/cm.A nonthermal,terahertz-induced depletion of low-frequency conductivity in Nb_(3)Sn indicates increased gap splitting of high-energy Г_(12) bands by removal of their degeneracies,which induces the martensitic phase above their equilibrium transition temperature.In contrast,optical pumping leads to a Г_(12) gap thermal melting.Such light-induced nonequilibrium martensitic phase exhibits a substantially enhanced critical temperature up to~100 K,i.e.,more than twice the equilibrium temperature,and can be stabilized beyond technologically relevant,nanosecond time scales.Together with first-principle simulations,we identify a compelling terahertz tuning mechanism of structural order via Г_(12) phonons to achieve the ultrafast phase transition to a metastable electronic state out of equilibrium at high temperatures far exceeding those for equilibrium states.
基金supported by the National Natural Science Foundation of China(Grant Nos.51227001 and 51471108)the SJTU-UNSW Cooperative Research Fund(16X120030005)
文摘A series Co-（18.5–20.7） at.% B melts encompassing the eutectic composition（Co81.5B18.5） were solidified at different degrees of undercooling. It is found that the metastable Co23B6 phase solidifies as a substitute for the stable Co3 B phase in the alloy melts undercooled above a critical undercooling value of -60 K.The Co23B6 and α-Co phases make up a metastable eutectic. The corresponding eutectic composition and temperature are Co80.4B19.6 and 1343 K, respectively. On exposure of the metastable Co23B6 phase at a given temperature above 1208 K, it does not decompose even after several hours. But it transforms by a eutectoid reaction to α-Co ＋ Co3 B at lower temperature.
基金European Fund for Regional Development of the European Union in the framework of the Berlin-Brandenburg-Polish joint project“From UV to blue—Reliable laser sources for environmental monitoring(RelyLa)”。
文摘Single longitudinal mode continuous-wave operation of GaN-based distributed Bragg reflector(DBR) laser diodes with 10 th-order surface gratings is demonstrated. The DBR consists of periodic V-shaped grooves on a 2 μm wide ridge waveguide fabricated by using electron-beam lithography and plasma etching. The effect of different lengths of the DBR section and the gain section on the device performance has been studied. Periodic mode hops to the adjacent longitudinal Fabry–Perot resonator mode at shorter wavelength have been observed when increasing the operation current. Between the mode hops, single longitudinal mode emission at around 405 nm is achieved with a full width at half-maximum of 0.03 nm. A linear redshift of the emission wavelength with increasing temperature of 0.019 nm/K was derived.
文摘The material and electrical properties of HfO 2 hi gh-k gate dielectric are reported.In the first part,the band alignment of H fO 2 and (HfO 2) x(Al 2O 3) 1-x to (100)Si substrate and thei r thermal stability are studied by X-ray photoelectron spectroscopy and TEM.The energy gap of (HfO 2) x(Al 2O 3) 1-x,the valence band offset, and the conduction band offset between (HfO 2) x(Al 2O 3) 1-x and the Si substrate as functions of x are obtained based on the XPS results .Our XPS results also demonstrate that both the thermal stability and the resist ance to oxygen diffusion of HfO 2 are improved by adding Al to form Hf aluminat es.In the second part,a thermally stable and high quality HfN/HfO 2 gate stack is reported.Negligible changes in equivalent oxide thickness (EOT),gate leakage, and work function (close to Si mid-gap) of HfN/HfO 2 gate stack are demonstrat ed even after 1000℃ post-metal annealing(PMA),which is attributed to the super ior oxygen diffusion barrier of HfN as well as the thermal stability of the HfN/ HfO 2 interface.Therefore,even without surface nitridation prior to HfO 2 depo sition,the EOT of HfN/HfO 2 gate stack has been successfully scaled down to les s than 1nm after 1000℃ PMA with excellent leakage and long-term reliability.T he last part demonstrates a novel replacement gate process employing a HfN dummy gate and sub-1nm EOT HfO 2 gate dielectric.The excellent thermal stability of the HfN/HfO 2 gate stack enables its use in high temperature CMOS processes.Th e replacement of HfN with other metal gate materials with work functions adequat e for n- and p-MOS is facilitated by a high etch selectivity of HfN with respe ct to HfO 2,without any degradation to the EOT,gate leakage,or TDDB characteris tics of HfO 2.
