[Application of cold flowable gutta-percha in root canal obturation after apexification].

OBJECTIVE: To evaluate the clinical effect of root canal obturation therapy using cold flowable gutta-percha on young permanent teeth after apexification. METHODS: Ninety cases of young permanent teeth with pulp necrosis or periapical periodontitis treated by apexification were randomly divided into two groups. The cases in each group were divided into single root canal and multiple root canal according to the number of the root canal, and divided into classifications Ⅰ, and Ⅱ/Ⅲ/Ⅳ according to Frank's classification of root development after apexification. Cold flowable gutta-percha and warm gutta-percha obturation techniques were used for root canal obturation of the two groups. The operation time was recorded, and the patients' therapy pain degree was evaluated by visual analog scale (VAS) immediately after operation. Periapical X-ray was performed after operation to evaluate the effect of the root canal filling. The total length of the root was divided into equal three parts on the X-ray film, and three-dimensional tightness of the apical, middle, and coronal region of the root canals were statistically analyzed respectively. Clinical examinations and X-ray examination were performed 6 and 12 months after the operation to evaluate the treatment success rate. RESULTS: The operation time of cold flowable gutta-percha group was significantly lower than that of the control group, which were 51 s and 74 s (P < 0.05); The percentages of pain and discomfort in the two groups were 26.67% and 40.00%, respectively. There were two cases of underfilling and no overfilling in both groups. The percentages of proper filling and tight three-dimensional obturation in the experimental and control groups were 71.11% and 60.00% respectively; and the percentages of tight three-dimensional obturation in the apical third areas were 86.67% and 66.67%, the difference was significant (P < 0.05). There was no significant difference in the three-dimensional tightness between the two groups in the middle and coronal third areas. The percentages of tight three-dimensional obturation in classification Ⅰ groups were 86.67%, 83.33%, 93.33% and 76.67%, 90.00%, 96.67% in experimental and control group, respectively; The percentages of classification Ⅱ/Ⅲ/Ⅳ groups were 86.67%, 86.67%, 100.00% and 46.67%, 86.67%, 100.00%, respectively, and the difference was significant (P < 0.05). There were no apical lesions that occurred in either group during the one-year review period. CONCLUSION: The application of cold flowable gutta-percha on young permanent teeth root canal obturation after apexification can achieve good obturation effect. The root obturation effect in the apical third area is significantly better than that of warm gutta-percha obturation techniques. Cold flowable gutta-percha can shorten the clinical treatment time and ameliorate the patients' therapy comfort.

Interactions between Golli-MBP and Th1/Th2 cytokines in patients with oral lichen planus.

OBJECTIVE: Oral lichen planus (OLP) is a prevalent cell-mediated autoimmune disease of unknown etiology. Disruption in the Th1/Th2 equilibrium has been suspected to contribute to the pathogenesis of OLP. In this study, we aimed at exploring, in OLP, the interactions between Th1/Th2 cytokines and Golli-MBP, a regulator of autogenic T cells. SUBJECTS AND METHODS: Thirty-six OLP patients aged 18-79 and nineteen control subjects aged 20-69 were enrolled in the dental clinics of Nanjing Medical University. OLP was diagnosed clinically and verified by histopathological examination. All subjects were free of other autoimmune diseases. Peripheral blood mononuclear cells (PBMC) and serum were collected from all subjects. Gene expression and protein levels of Golli-MBP, IFN-γ and IL-4 were measured, respectively, by semiquantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. RESULT: When compared with control, PBMC and serum from OLP patients exhibited a significantly higher expression and concentration of Golli-MBP and IL-4 and lower levels of IFN-γ. A strong negative correlation (r = -0.838, P < 0.000) was detected between the ratio of IFN-γ/IL-4 and Golli-MBP gene expression in PBMCs of OLP patients. CONCLUSION: These data support a potential link between Golli-MBP and the dysregulation of the Th1/Th2 equilibrium in OLP.

Quality of root fillings performed with two root filling techniques. An in vitro study using micro-CT.

OBJECTIVE: The aim of this study was to compare the presence of voids in root fillings performed in oval and ribbon-shaped canals with two root filling techniques, lateral compaction technique (LCT) or hybrid technique (HT), a combination of a gutta-percha masterpoint and thermoplastic gutta-percha. Furthermore, the obturation time for the two techniques was evaluated. MATERIALS AND METHODS: Sixty-seven roots with oval and ribbon-shaped canals were prepared using Profile Ni-Ti rotary files. After preparation, the roots were randomly allocated to two groups according to root filling technique. All roots were filled with AH plus and gutta-percha. Group 1 was filled using LCT (n = 34) and group 2 was filled using HT (n = 33). The obturation time was measured in 30 cases evenly distributed between the two techniques. Voids in relation to the root canal fillings were assessed using cross-section images from Micro-computed Tomography scans. RESULTS: All root canal fillings had voids. Permutation test showed no statistically significant difference between the two root filling techniques in relation to presence of voids (p = 0.092). A statistically significant difference in obturation time between the two techniques was found (p < 0.001). CONCLUSION: The present study found no statistically significant difference in percentage of voids between two root filling techniques. A 40% reduction in obturation time was found for the HT compared to the LCT.

Accurate occlusion-driven maxillary reconstruction with deep circumflex iliac artery flap using computer-assisted techniques and intraoral anastomosis: a case series.

The aim of this study was to evaluate the feasibility and accuracy of occlusion-driven maxillary reconstruction with the deep circumflex iliac artery (DCIA) flap, using computer-assisted design and manufacturing (CAD/CAM) technology and intraoral anastomosis. The data of 11 patients who underwent occlusion-driven maxillary reconstruction with this method between December 2018 and December 2020 in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology were reviewed retrospectively. Postoperative complications and functional and aesthetic outcomes were recorded. The accuracy of the postoperative restoration was assessed using Geomagic Control 2014. Reconstruction was successful in nine patients; all were satisfied with their aesthetic and functional outcomes. One patient underwent extraoral anastomosis after failure of intraoral anastomosis. In another patient, the DCIA flap had to be removed after the operation because of flap failure. Among the 10 patients with DCIA flap success, colour map analysis showed a mean deviation of 0.40 ± 0.08 mm between the preoperative and postoperative craniomaxillary models. Thus, occlusion-driven maxillary reconstruction with the DCIA flap, using CAD/CAM technology and intraoral anastomosis, appears to be a feasible and accurate method for the repair of maxillary defects.

An umbrella review exploring the effect of radiotherapy for head and neck cancer patients on the frequency of jaws osteoradionecrosis.

OBJECTIVE: Efforts have been made to reduce epidemiological indicators of osteoradionecrosis in patients with head and neck cancer over recent years. This umbrella review aims to synthesize the information of the systematic reviews/meta-analyses investigating the effect of radiotherapy in patients with head and neck cancer on the frequency of osteoradionecrosis and to identify and analyze the gaps in current scientific literature. MATERIAL AND METHODS: A systematic review of systematic reviews with and without meta-analysis of intervention studies was conducted. Qualitative analysis of the reviews and their quality evaluation were performed. RESULTS: A total of 152 articles were obtained, and ten of them were selected for the final analysis, where six were systematic reviews and four were meta-analysis. According to the guide Assessing the Methodological Quality of Systematic Reviews (Amstar), eight articles included were of high quality and two of medium quality. These descriptive systematic reviews/meta-analyses included a total of 25 randomized clinical trials, showing that radiotherapy has positive effects on the frequency of osteoradionecrosis. Even though a reduction in the incidence of osteoradionecrosis was observed back in the history, in systematic reviews with meta-analysis, overall effect estimators were not significant. CONCLUSIONS: Differential findings are not enough to demonstrate that there is a significant reduction in the frequency of osteoradionecrosis in patients with head and neck cancer treated by radiation. Possible explanations are related to factors such as the type of studies analyzed, indicator of irradiated complication considered, and specific variables included in the analysis. Many systematic reviews did not address publication bias and did identify gaps in knowledge that require further clarification.

Portable fluid circuit device containing printed silicone microvessels as a training aid for arterial microanastomosis.

Anastomosis of the microvessels requires high-level skills and extensive basic training. This study was performed to introduce and evaluate an inexpensive laboratory device as a training aid. Micro-tubes of 0.8 mm inner diameter and 0.5/0.8 mm wall thickness mimicking human vein/artery were printed from a silicon-containing hydrogel using three-dimensional printing technology. The hydrogel components are optimized to render the printed tubes biomechanical features resembling the blood vessels of a living organism. These artificial vessels were connected to a pump for fluid flow, simulating the blood circulation. Forty medical interns were assigned to two equal groups. The 20 interns in group A practiced anastomosis using the training aid for a total of 10 hours over 5 days. The 20 interns in group B practiced anastomosis using the traditional gum pieces and silicone tubes. Then, all interns performed anastomosis on rat carotid arteries, and their performance was scored by a team of five experienced maxillofacial surgeons. The average success score and time required for anastomosis were compared between the two groups. The mean success score of group A was significantly higher than that of group B (0.83 ± 0.12 vs 0.64 ± 0.10, P < 0.001). The mean anastomosis time of group A was significantly shorter than that of group B (10.2 ± 1.1 vs 17.2 ± 1.4 minutes, P < 0.001). This training device for vessel microanastomosis is an inexpensive, practical, and effective tool for use in laboratories and also reduces the use of animals.

Fabrication and characterization of elastomeric polyester/carbon nanotubes nanocomposites for biomedical application.

A novel biodegradable polymer elastomer nanocomposite composing of poly(1,8-octanediol-citrate) (POC) polymer matrix and carbon nanotubes (CNTs) additive was successfully fabricated and systematically investigated using Fourier transform infrared (FT-IR), X-ray diffractometer (XRD), differential scanning calorimetry (DSC), tensile test, incubation and cytotoxicity tests. It was found that the addition of CNTs in POC elastomer did not result in any noticeable change in its chemical structure and the amorphous state. However, the tensile strength and elongation at break were greatly improved by the addition of CNTs in POC polymer matrix. It revealed that the swelling ratio and percentage of weight loss of POC/CNTs nanocomposite were lower, compared with the pure POC material. Moreover, the adsorption amount of bovine serum albumin (BSA) increased with an increase of the CNTs mass content in POC matrix revealing the enhanced hydrophilicity of POC/CNTs nanocomposites contributed by the carboxyl of the CNTs. Additionally, the cytotoxicity tests with L929 cell line revealed that the experimental POC/CNTs nanocomposites possessed good in vitro biocompatibility.

Mechanical strength of ceramic scaffolds reinforced with biopolymers is comparable to that of human bone.

Eight groups of calcium-phosphate scaffolds for bone implantation were prepared of which seven were reinforced with biopolymers, poly lactic acid (PLA) or hyaluronic acid in different concentrations in order to increase the mechanical strength, without significantly impairing the microarchitecture. Controls were un-reinforced calcium-phosphate scaffolds. Microarchitectural properties were quantified using micro-CT scanning. Mechanical properties were evaluated by destructive compression testing. Results showed that adding 10 or 15% PLA to the scaffold significantly increased the mechanical strength. The increase in mechanical strength was seen as a result of increased scaffold thickness and changes to plate-like structure. However, the porosity was significantly lowered as a consequence of adding 15% PLA, whereas adding 10% PLA had no significant effect on porosity. Hyaluronic acid had no significant effect on mechanical strength. The novel composite scaffold is comparable to that of human bone which may be suitable for transplantation in specific weight-bearing situations, such as long bone repair.

Sequential treatment by polidocanol and radiofrequency ablation of large benign partially cystic thyroid nodules with solid components: Efficacy and safety.

PURPOSE: The purpose of this study was to retrospectively evaluate the efficacy and safety of a sequential treatment including percutaneous polidocanol sclerotherapy and radiofrequency ablation (RFA) in terms of volume reduction and complication rate in large, benign, partially cystic thyroid nodules with solid components. MATERIALS AND METHOD: From April 2017 to April 2019, 46 patients with 47 large benign partially cystic thyroid nodules underwent sequential treatment. There were 14 men and 32 women with a mean age of 49.9±11.5 (SD) years (range: 18-75 years). The volume of initial nodules was 12.7±12.3 (SD) mL (range: 2.16-75.62mL). Volume reduction after percutaneous polidocanol sclerotherapy and further RFA was evaluated respectively. Patients had clinical and ultrasound evaluations at a follow-up time of 12.1±5.3 (SD) months (range: 1.5-23.9 months). Technical success and complications were accessed retrospectively. RESULTS: After unsatisfying results with polidocanol sclerotherapy alone the 46 patients with 47 large benign partially cystic thyroid nodules had further RFA. Mean volume reduction of 47 nodules was 90.5±11.3 (SD) % (range: 43.9-99.3%) one month after RFA, 94.9±6.2 (SD) % (range: 66.9-99.5%) three months after RFA, and 95.8±5.5 (SD) % (range: 71.0-99.8%) six months after RFA. No recurrence or nodule enlargement after RFA was observed at the last follow-up. The complication rate of RFA was 12.5% (8/46 patients), with minor complications only. CONCLUSIONS: The sequential treatment regimen, including percutaneous polidocanol sclerotherapy and RFA, is an appropriate and safe treatment strategy for large benign partially cystic thyroid nodules with solid components.

Discovery and identification of fatigue-related biomarkers in human saliva.

OBJECTIVE: To identify stable and specific biomarkers/biomarker combinations for fatigue assessment and establish a discriminant model. PATIENTS AND METHODS: Saliva was collected and electroencephalogram analysis was performed for 47 emergency physicians while awake and after continuoutas duty for 18-24 h. Physicians were divided into the fatigue and non-fatigue groups. Protein spectra of completely quantified saliva specimens were identified before and after long working hours using mass spectrometry. Data were analyzed through Proteome Discoverer software combined with SEQUEST to search protein databases. Proteins were characterized by collision-induced dissociation spectra. A global internal standard (GIS) was added to each group of samples and labeled by tandem mass tags m/z 131.1. All data were compared with GIS, and data between groups were further compared. Qualitative and quantitative data on proteins were exported for fatigue-related proteomic analysis, and a fatigue assessment model was established. RESULTS: We identified 767 salivary proteins in the fatigue group. The correct rates of the discriminant function of the non-fatigue and fatigue groups were 97.1% and 91.7%, respectively (the total correct rate was 95.7%). CONCLUSIONS: We identified 30 fatigue-related protein markers from saliva. We also established a fatigue assessment model for emergency physicians using salivary biomarkers.

Flexibility and nucleation in sickle hemoglobin.

We have studied the self-assembly of Hemoglobin C-Harlem (HbC-Harlem), a double mutant of hemoglobin that possesses the beta6 Glu-->Val mutation of sickle hemoglobin (HbS) plus beta73 Asp-->Asn. By electron microscopy we find it forms crystals, rather than the wrapped multistranded fibers seen in HbS. Fourier transforms of the crystals yield unit cell parameters indistinguishable from crystals of HbS. Differential interference contrast (DIC) microscopy and birefringence also show crystal formation rather than the polymers or domains seen for HbS, while the growth patterns showed radiating crystal structures rather than simple linear crystalline forms. The solubility of the assembly was measured using a photolytic micromethod over a temperature range of 17-31 degrees C in 0.15 M phosphate buffer and found to be essentially the same as that of fibers of HbS. The assembly kinetics were observed by photolysis of the carbon monoxide derivative, and the mass of assembled hemoglobin was found to grow exponentially, with onset times that were stochastically distributed for small volumes. The stochastic onset of assembly showed strong concentration dependence, similar to but slightly greater than that seen in sickle hemoglobin nucleation. These observations suggest that like HbS, HbC-Harlem assembly proceeds by a homogeneous nucleation process, followed by heterogeneous nucleation. However, relative to HbS, both homogeneous and heterogeneous nucleation are suppressed by almost 11 orders of magnitude. The slowness of nucleation can be reconciled with the similarity of the solubility to HbS by an increase in contact energy coupled with a decrease in vibrational entropy recovered on assembly. This also explains the linearity of the double-strands, and agrees with the chemical nature of the structural replacement.

Polyethylene glycol-conjugated superoxide dismutase attenuates reperfusion injury when administered twenty-four hours before ischemia.

Covalent linkage of polyethylene glycol to superoxide dismutase prolongs the serum half-life of the enzyme and may facilitate intracellular access. We tested the myocardial protective effect of polyethylene glycol superoxide dismutase administered once, 24 hours before ischemia. Because hearts were studied ex vivo in a crystalloid perfused system, cardioprotection could be ascribed to intramyocardial or membrane-bound polyethylene glycol superoxide dismutase accumulation. Thirty isolated rabbit hearts from the four following groups were studied: (1) control: untreated rabbits (n = 7); (2) PEG-control: 24-hour intravenous preinfusion of methoxypolyethylene glycol 5000 (5 mg/kg) to examine the effect of polyethylene glycol alone, without conjugation to superoxide dismutase (n = 8); (3) PEG-SOD 10,000: 24-hour preinfusion of polyethylene glycol superoxide dismutase (10,000 U/kg) (n = 8); (4) PEG-SOD 30,000: 24-hour preinfusion of polyethylene glycol superoxide dismutase (30,000 U/kg) (n = 7). After measurement of baseline function with use of an intraventricular balloon, hearts were subjected to normothermic ischemia until a 4 mm Hg rise in intracavitary pressure was observed. Function was assessed at 15-minute intervals throughout reperfusion and expressed as percent return of developed pressure. After 60 minutes of reperfusion, recovery of function was greater for the PEG-SOD 30,000 group (85.6% +/- 2.6%) when compared with either the untreated or PEG-control group (68.9% +/- 2.3% and 71.4% +/- 2.0%, respectively). A similar difference was seen throughout reperfusion. Although an improved return of function was shown in the lower dose PEG-SOD 10,000 group, the margin of difference when compared with any of the control groups was determined to be insignificant at all times of reperfusion and at 60 minutes (75.9% +/- 3.2%). These data demonstrate that high, but not low, doses of polyethylene glycol superoxide dismutase significantly reduce reperfusion injury when administered 24 hours before initiation of global ischemia. Moreover, since the perfusate was superoxide dismutase free, this effect was most likely intramyocardial or membrane bound and therefore might be added to protection afforded by circulating superoxide dismutase.

Localization of adenovirus DNA by in situ hybridization electron microscopy.

Biotinylated deoxyadenosine triphosphate (dATP) (Bio-7-dATP) and 3H deoxythymidine triphosphate (dTTP) labeled adenovirus DNA were hybridized in situ to thin sections of Lowicryl K4M-embedded and whole-mount extracted HeLa cells infected with adenovirus. The biotinylated probe was detected by exposing the extracted cells or sections to antibodies against biotin followed by colloidal gold-conjugated secondary antibodies and then critical-point dried while 3H-dTTP labeled probe by electron microscopic autoradiography. On Lowicryl K4M sections, gold particles and silver grains were mainly restricted in the nucleus. Furthermore, whole-mount results suggested that replicating adenovirus DNA is localized on the nuclear matrix of its host cell. In this paper, the described non-radioactive procedures for hybrid detection offered several advantages: a) rapid signal detection; b) superior morphological preservation and spatial resolution; c) precise localization; and d) on Lowicryl K4M sections, signal to noise equivalent to radiolabeling.

Changed morphology and mechanical properties of cancellous bone in the mandibular condyles of edentate people.

Since edentate subjects have a reduced masticatory function, it can be expected that the morphology of the cancellous bone of their mandibular condyles has changed according to the altered mechanical environment. In the present study, the morphology of cylindrical cancellous bone specimens of the mandibular condyles of edentate subjects (n = 25) was compared with that of dentate subjects (n = 24) by means of micro-computed tomography and by the application of Archimedes' principle. Stiffness and strength were determined by destructive mechanical testing. Compared with dentate subjects, it appeared that, in edentate subjects, the bone was less dense and the trabecular structure was less plate-like. The regression models of stiffness and strength built from bone volume fraction and the trabecular orientation relative to the axis of the specimen were similar for both dentate and edentate subjects. This indicates that, under reduced mechanical load, the fundamental relationship between bone morphology and mechanical properties does not change.

Intraocular lens material evaluation by iris abrasion in vitro: a scanning electron microscope study.

Prosthetic posterior chamber intraocular lenses can abrade the iris pigmented epithelium, resulting in pigment dispersion, callus formation, and iris adhesions. To evaluate iris abrasion from intraocular lens materials, we developed an in vitro test and studied three materials: polymethylmethacrylate (PMMA), silicone, and PMMA surface-modified by covalent binding of a hydrophilic polymer (surface-modified PMMA). Each lens was rubbed 1,000 times on the posterior iris of pigmented rabbits using a total force of 0.5 gram. Scanning electron micrographs of the abraded irides were scored using a subjective, nonparametric numerical scale. Polymethyl-methacrylate lenses removed iris epithelium completely, exposing underlying connective tissue. Silicone lenses damaged an area longer and narrower than the PMMA lens and also exposed connective tissue. Surface-modified PMMA lenses caused only slight surface damage, including flattening or breaking of protruding suspensory ligaments. The test conditions used cannot precisely mimic prolonged lens implantation in living subjects. Nevertheless, the results indicate that iris-lens interaction may be reduced in vivo by using a surface-modified PMMA lens. This hypothesis should be further verified by animal implantation studies.

Rapid, direct determination of polyphenols in tea by reversed-phase column liquid chromatography.

Column liquid chromatography on a C18-bonded silica column with water-methanol-acetic acid as eluent was used to determine polyphenols and caffeine in tea. Without any pretreatment, catechin, epicatechin gallate, epigallocatechin gallate, epigallocatechin, epicatechin and caffeine were separated successfully within 15 min. The detection limits (S/N = 3) of polyphenols studied were 1.8-24 mg/l at a detection wavelength 270 nm. The linear range of the peak area calibration curves for the analytes were over two orders of magnitude with a correlation coefficient of 0.996-0.999. Using this method, some Chinese tea samples were analyzed with a good reproducibility (RSD are below 5%).

Mechanical properties of cancellous bone in the human mandibular condyle are anisotropic.

The objective of the present study was (1) to test the hypothesis that the elastic and failure properties of the cancellous bone of the mandibular condyle depend on the loading direction, and (2) to relate these properties to bone density parameters. Uniaxial compression tests were performed on cylindrical specimens (n=47) obtained from the condyles of 24 embalmed cadavers. Two loading directions were examined, i.e., a direction coinciding with the predominant orientation of the plate-like trabeculae (axial loading) and a direction perpendicular to the plate-like trabeculae (transverse loading). Archimedes' principle was applied to determine bone density parameters. The cancellous bone was in axial loading 3.4 times stiffer and 2.8 times stronger upon failure than in transverse loading. High coefficients of correlation were found among the various mechanical properties and between them and the apparent density and volume fraction. The anisotropic mechanical properties can possibly be considered as a mechanical adaptation to the loading of the condyle in vivo.

Reduced mechanical load decreases the density, stiffness, and strength of cancellous bone of the mandibular condyle.

OBJECTIVE: To investigate the influence of decreased mechanical loading on the density and mechanical properties of the cancellous bone of the human mandibular condyle. DESIGN: Destructive compressive mechanical tests were performed on cancellous bone specimens.Background. Reduced masticatory function in edentate people leads to a reduction of forces acting on the mandible. As bone reacts to its mechanical environment a change in its material properties can be expected. METHODS: Cylindrical bone specimens were obtained from dentate and edentate embalmed cadavers. Mechanical parameters were determined in the axial and in the transverse directions. Subsequently, density parameters were determined according to a method based on Archimedes' principle. RESULTS: The apparent density and volume fraction of the bone were about 18% lower in the edentate group; no age-related effect on density was found. The decrease of bone in the edentate group was associated with a lower stiffness and strength (about 22% and 28%, respectively). The ultimate strain, however, did not differ between the two groups. Both groups had similar mechanical anisotropy; in axial loading the bone was stiffer and stronger than in transverse loading. CONCLUSIONS: Reduced mechanical load had affected the density and herewith the mechanical properties of condylar cancellous bone, but not its anisotropy. RELEVANCE: The change in material properties of the cancellous bone after loss of teeth indicate that the mandibular condyle is sensitive for changes in its mechanical environment. Therefore, changes in mechanical loading of the condyle have to be accounted for in surgical procedures of the mandible.

A novel copper/polydimethiylsiloxane nanocomposite for copper-containing intrauterine contraceptive devices.

In this article, a novel composite of copper (Cu) nanoparticles and polydimethiylsiloxane (PDMS) has been prepared and investigated for the potential application in Cu-containing intrauterine device. The Cu/PDMS composite with various mass fraction of Cu nanoparticles was fabricated via the hot vulcanizing process. The chemical structures and surface morphologies of the Cu/PDMS composites were characterized confirming the physical interaction between Cu nanoparticles and PDMS. The surface morphology observation using scanning electron microscope and atomic force microscope showed the agglomeration of Cu nanoparticles in PDMS matrix and the distribution of the agglomerations was more uniform with increased amount of Cu nanoparticles. The cupric ion release behaviors of the Cu/PDMS composites with different amounts of Cu nanoparticles were investigated in simulated uterine fluid at 37°C for 150 days. The corrosion morphologies of the Cu/PDMS composites were also characterized. Both the burst release rate of the cupric ion in the first few days and the steady release rate after 30-day immersion were improved. The cytotoxicity test has been done for the Cu/PDMS composites.

[Chromatographic analysis of tea polyphenols].

A review is presented about the chromatographic analysis of the polyphenols. Some of the chromatographic methods such as plate chromatography, gas chromatography, reversed-phase high performance liquid chromatography and some new chromatographic methods are introduced.