侵袭性牙周炎是好发于青年人群,以进展迅速、破坏严重为特征,伴有家族聚集性的一类牙周炎.唾液中生物标记物能实时反映口腔软组织和硬组织、口腔内微生物的状态,在侵袭性牙周炎的诊断中有运用潜力,并可监测其活动状态.同时,唾液诊断具有廉价、无创、简便、舒适等优点.因此,唾液中的生物标记物有助于侵袭性牙周炎的早期诊断、实时监测.本文对侵袭性牙周炎唾液诊断标记物的研究现状进行综述,以期为侵袭性牙周炎唾液诊断提供思路.

A metabolic syndrome is characterized by symptoms of metabolic disorders,such as proteins,fats,and carbohydrates associated with increased risks of cardiovascular diseases and diabetes mellitus.Recent evidence has proposed the relationship between periodontitis and metabolic syndrome.In this review,progress on the role of inflammation and oxidative stress and the relationship of oral microbes with the main characteristics of metabolic syndrome is presented to provide new insights into the prevention and intervention of metabolic syndrome.

The failure behavior and its mechanism of time-temperature superposition (TTS) poly(vinyl chloride) (PVC)/dioctylphthalate (DOP) (100/70) system were studied from low to high temperatures with a step of 10 degrees C. Arrhenius equation, WLF equation, mathematical nonlinear fitting, and manual shift were applied for TTS fitting. None of these methods could obtain the well-superposed master curves with either single horizontal shift or two-dimensional (horizontal and vertical) shift. The rheological data and differential scanning calorimeter (DSC) results were used to explain the failure mechanism of the TTS fitting. The curves of storage modulus versus frequency were well fitted to an empirical equation G' = G(0)' + K omega(n). The yield behavior was used to analyze the influence of test temperature on the dynamic rheological behavior for the PVC/DOP (100/70) system. A transition of rheological behavior from the solid-like to the linear viscoelastic could be observed at 190 degrees C because of the gradual melting of microcrystallites and the destruction of gel networks, which were confirmed by DSC analysis. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The dynamic rheological behavior, application of time-temperature superposition (TTS) and the failure mechanism of TTS are studied for the poly(vinyl chloride) (PVC)/trioctyl trimellitate (TOTM) (100/70) system. The Arrhenius equation, Williams-Landel-Ferry (WLF) equation, mathematical non-linear fitting and manual shift are applied to TTS fitting. For the PVC/TOTM (100/70) system, none of those methods can give well-superimposed master curves with either single horizontal shift or two-dimensional (horizontal and vertical) shift. The failure reason is attributed to the thermorheological complexity of the PVC/TOTM(100/70) system. Curves of the storage modulus versus the frequency can be well fitted with an empirical equation (G' = G(0)' + K omega(n)) usually used to describe filled polymer systems, indicating the multilevel flowing unit characteristic in this system. With the increase of test temperature, the structure of the PVC/TOTM (100/70) system changes and an apparent transition appears in the rheological behavior. Differential scanning calorimetry (DSC) results reveal that for the PVC/TOTM (100/70) system there are microcrystallites present below 220 degrees C, but above the rheological transition temperature (190 degrees C) the bulk of the microcrystallites melted, which corresponds to the appearance of viscous flow participating in the rheological behavior. It verifies the fact that the gel networks crosslinked by microcrystallites dominate the rheological behavior below the transition temperature in the PVC/TOTM (100/70) system. The quantity of microcrystallites remaining in the melt determines the perfection of the physical gel networks. With the increase of test temperature, the microcrystallites melted gradually and the gel networks are broken up.

The effect of chlorinated polyethylene (CPE) content and test temperature on the notched Izod impact strength and brittle-ductile transition behaviors for polyvinylchloride (PVC)/CPE blends and PVC/CPE/nano-CaCO3 ternary composites is studied. The CPE content and the test temperature regions are from 0-50 phr and 243-363 K, respectively. It is found that the optimum nano-CaCO3 content is 15 phr for PVC/CPE/nano-CaCO3 ternary composites. For both PVC/CPE blends and PVC/CPE/nano-CaCO3 ternary composites, the impact strength is improved remarkably when the CPE content or test temperature is higher than the critical value, that is, brittle-ductile transition content (C-BD) or brittle-ductile transition temperature (T-BD). The T-BD is closely related to the CPE content, the higher the CPE content, the lower the T-BD. The temperature dependence of impact strength for PVC/CPE blends and PVC/CPE/nano-CaCO3 ternary composites can be well simulated with a logistic fitting model, and the simulation results can be illustrated with the percolation model proposed by Wu and Jiang. DMA results reveal that both PVC and CPE can affect the T-BD of PVC/CPE blends and PVC/CPE/nano-CaCO3 composites. When the CPE content is enough (20 phr), the CPE is more important than PVC for determining the T-BD of PVC/CPE blends and PVC/CPE/nano-CaCO3 composites. Scanning electron microscopy (SEM) observations reveal that the impact fractured mechanism can change from brittle to ductile with increasing test temperature for these PVC systems. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1833-1842, 2012

In order to study the influence of particle shape and size of inorganic fillers on the conductive property of poly(vinyl chloride)/chlorinated polyethylene/carbon black(PVC/CPE/CB) composites,SiO2(spherical),talc(flake),glass fiber (fiber),nano-CaCO3 and ordinary CaCO3 were adopted to prepare PVC/CPE/CB/filler composites,and the conductive properties and morphological structure of these composites were studied.The experimental results reveal that compared with the spherical and flake filler,the addition of fiber filler is in favour of maintaining conductive properties of PVC/CPE/CB/filler composites,and nano-CaCO3 have less impact on the PVC/CPE/CB/filler composites.When the CB content is 12phr and the nano-CaCO3 content is 15phr,the volume resistivity of PVC/CPE/CB/nano-CaCO3 composites is 6.04×106 Ω·cm.

A new kind of impact master batch was prepared from PVC,nano-CaCO3 and CPE by mechanochemical vibromilling process,and optimal formulation was investigated.Influences of master batch on mechanical properties,micromorphology and processing properties of PVC were studied.The results show that: ① in the master batch formulation,the optimum mass ratio of nano-CaCO3/PVC is 9∶1;② when the dosage of V-90 is 15 parts,samples with the best performance can be obtained;③ the ruptured surfaces of composites with Master Batch V-90 exhibit obvious ductile fracture pattern;④ Master Batch V-90 can shorten the fusion time of PVC,increase its maximum torque and equiponderance torque,and improve its processing properties.

Scanning electron microscope (SEM) results reveal that at a lower processing temperature and rotor rotation speed,only part of PVC particles is plasticated and cohered with each other at the peak of plasticating curve.All PVC particles are plasticated only when the processing time is longer enough than that of plastication peak.But all PVC particles are plasticated quickly in higher processing temperature.DSC data reveal that processing temperature,time and rotor's rotation speed also affect the crystalline and gelation degree of PVC.At 150 ℃,the gelation degree increases greatly when rotation speed increases.At 30 r/min and 5 min,w the gelation degree increases dramatically when temperature increases.At the same rotation speed,when processing time increase,the gelation degree quickly increases and then reaches balance related temperature and rotation speed.