Refractive Index Changes in Polymers Induced by Deep UV Irradiation and Subsequent Gas Phase Modification

Poly(4‐vinylbenzyl thiocyanate) (PVBT) and a copolymer of styrene and 4‐vinylbenzyl thiocyanate (PST‐co‐VBT) were investigated with regard to changes of the refractive index under UV irradiation (λ = 254 nm). After irradiation, the refractive index n_D of PVBT films increased from 1.629 to 1.660. In the case of the copolymer PST‐co‐VBT, n_D increased from 1.616 to 1.630. The change of the refractive index mainly resulted from the photoinduced isomerization of thiocyanate groups (SCN) to the corresponding isothiocyanates (NCS). The NCS groups formed in the irradiated zones were selectively modified with gaseous amines (ammonia, propylamine, ethylenediamine, and hydrazine) to give thiourea derivatives via an addition reaction. The gas phase modification induced further changes of the refractive index without any loss of the film quality (e. g. propylamine, Δn up to –0.026, and hydrazine, Δn up to +0.035). In addition, the thickness h of the polymer films increased by up to 21% as a result of the gas phase modification. In contrast, wet chemical treatment with bulky amines (1‐methylnaphthylamine, 1‐pyrenemethylamine) caused a considerable deterioration of the film quality. The variation of the refractive index in polymers such as PVBT and PST‐co‐VBT is of potential interest for holographic recordings and the setup of polymer based DFB lasers.     

Analysis of Soft Tissue Changes after Genioplasty in Skeletal Class III Dentofacial Deformity

Purpose

The purpose of this study was to measure the anteroinferior changes and the degree of vertical changes to facilitate the prediction of treatment outcome in patients undergoing genioplasty only, genioplasty with bilateral sagittal split ramus osteotomy (BSSRO), genioplasty, or BSSRO and Lefort I osteotomy.

Materials and Methods

Serial cephalometry was performed on 25 patients at 1-year follow-up after genioplasty, to assess skeletal changes and relapse. Surgery was performed using conventional techniques.

Results

The mean ratio was 0.9 : 1 of soft tissue to skeletal movement at pogonion, but the average difference between hard and soft tissue was large; thus, the prediction of anteroposterior soft tissue changes was quite inaccurate.

Conclusion

We observed a good correlation between the amount of hard versus soft tissue change with surgery in the horizontal direction, but a poor correlation in the vertical plane.     

Morphological Changes in Paraurethral Area after Introduction of Tissue Engineering Construct on the Basis of Adipose Tissue Stromal Cells

We studied morphological changes in the paraurethral area of Wistar rats after introduction of tissue engineering constructs on the basis of multipotent mesenchymal stem cells and gelatin sponge. The tissue engineering construct containing autologous culture of the stromal fraction of the adipose tissue was most effective. After introduction of this construct we observed more rapid degradation of the construct matrix and more intensive formation of collagen fibers.     

实验高压电烧伤深筋膜微循环动态变化及意义

目的研究肢体高压电烧伤后深筋膜微循环变化规律。方法将28只家兔随机分成实验组与对照组。实验组家兔的右下肢采用1万伏额定电压 ,77mA电流及通电5s的方法制作单侧后肢电烧伤模型 ,对照组采用假电的方法制作单侧后肢假电烧伤模型 ,两组均采用“滴水开窗法”制作左侧下肢远端深筋膜微循环观测窗 ,并采用WX -9B型多部位微循环显微仪及其图像处理系统在通电前、通电后即刻、通电后30min、2、4、6h观测微动脉、毛细血管、后微静脉、微静脉的形态、流态、管周状态。结果肢体高压电烧伤后 ,微血管形态在30min内可观测到显著性变化 (P<0.05) ,表现为血管密度减小 ,微动脉、毛细血管、微静脉收缩 ,后微静脉扩张 ,微动脉、毛细血管均在6min以后变得不清以致模糊(P<0.05)、后微静脉、微静脉分别在2h、30min以后变得不清(P<0.05)。微血管内的流态以白微栓的变化可见规律性 ,即白微栓在电后2h开始出现 ,4h迅速达高峰 ,6h又有快速下降的趋势。微静脉和后微静脉在通电30min后有渗出(P<0.05) ,只有后微静脉在通电后2h有出血(P<0.05)。结论电烧伤后存在全身性反应 ,其在肢端深筋膜微循环的表现是一个阶段性加重的过程 :第一阶段电烧伤后30min内为缺血型微循环障碍 ,第二阶段微循环障碍包含两个方面 :其一是微血管的出血     

Q开关Nd:YAG激光去除豚鼠文身的皮肤色度测量和组织学变化

目的：研究Q开关Nd：YAG激光作用不同颜色的豚鼠文身后不同时期文身色度的变化，对文身去除作用进行定量分析，并观察皮肤组织的变化，探讨文身色度变化与组织学变化的关系和文身去除在细胞水平上的作用机制。材料与方法：分别以1064nm和532nm波长的激光对红、绿和蓝色的豚鼠文身进行照射，照射后的不同时期作色度测量及组织学检查。结果：（1）与对照组比较，1064nm波长的激光照射后，红色文身的色度值没有显著性差异；绿色、蓝色文身的色度值有显著性差异。532nm波长的激光照射后，红色文身的色度值有显著性差异；绿色、蓝色文身的色度值没有显著性差异。（2）光学显微镜观察到特定波长激光照射后不同时期文身色素颗粒密度降低。结论：1064nm波长的激光对绿色、蓝色文身的去除效果较好，对红色文身治疗效果不明显；532nm波长的激光对红色文身去除效果好，但对绿色、蓝色文身未见有作用。     

微波辐射法氧化制备低分子量壳聚糖的实验研究

应用微波辐射技术氧化制备低分子量的壳聚糖，对影响壳聚糖分子量的工艺因素，如过氧化氢溶液浓度、反应时间、壳聚糖与过氧化氢溶液的固液比、微波功率等分别进行了实验研究。结果表明：在温度为70℃～80℃的条件下，用5％的H2O2，壳聚糖质量为8克时，可将高分子量的壳聚糖氧化成产率较高的低分子量壳聚糖。     

Experimental Study of Detection of Brain Tissue with Electrical Impedance Tomography after Cerebral Ischemic

Intracerebral haemorrhage(ICH), which has rapid attack and high death rate, usually leads to bad outcomes. Poor prognosis of this disease is primarily due to the difficulty of early discovery. Early detection or diagnosis would significantly reduce the rate of disability and mortality, and improve the prognosis of the patients. The purpose of this paper is to testify electrical impedance change and detection of brain tissue after cerebral ischemic with electrical impedance tomography. In this study, electrical impedance tomography(EIT) was applied to detect the onset of modeled on rabbits in real time, ICH model group were injected collagenase in the Corpus Striatum while rabbits in control group were injected the same volume of saline with collagenase. The subsequent process was monitored continuously by system of electrical impedance tomography;the rabbits were sacrificed by intravenous injection of over dose of hydration chlorine aldehyde, and then taken into being scanned by computed tomography(CT) with a resolution of l mm within 10 min after death. After that, the brains of the rabbits were taken out,fixed and cut into slices to detect the changes of brain tissue. We found that onedimensional impedance and two-dimensional(2D) images of electric resistance of brain of the rabbits pretreated with collagenase obviously changed after injection and the hemorrhage could be found in the slices of brain and there were changes in the model rabbits group not only the electric resistance but also the brain tissues.Although quantitative index can't be provided by detection of intracerebral hemorrhage in rabbits with electrical impedance tomography's at this stage, cerebral hemorrhage can cause brain electrical impedance characters of the change, the completed experiments suggest that electrical impedance tomography(EIT) may become an effective technique to detect ICH.     

The Use of Low-Power Laser Irradiation for Faster Vascularization of Tissue Transplants

We studied the effect of low-power laser irradiation on vascularization and take of transplanted rabbit renal and pancreatic tissue in athymic nude mice. The mean size of the transplant and the number of blood vessels in it were higher in irradiated mice compared to nonirradiated controls. Moreover, the organ-specific structure of the transplants was preserved in irradiated mice, but not in the control group. These findings suggest that low-power laser irradiation can be used for promotion of vascularization and take of tissue transplants.     

Effects of Relaxin on Relapse and Periodontal Tissue Remodeling after Experimental Tooth Movement in Rats

The relapse of teeth that have moved during orthodontic treatment is a major clinical issue with respect to the goals of successful treatment. Relaxin has an influence on many physiologic processes, such as collagen turnover. In this study, we determined the effects of relaxin on the relapse and remodeling of periodontal tissue after experimental tooth movement in rats, and we explored the molecular mechanism underlying these processes. To induce experimental tooth movement in rats, 10 g of orthodontic force was applied to the molars. After 14 days, the spring was removed, and then animals began receiving relaxin at a dose of 500 ng/ml for 1 week. The results were evaluated by micro-computed tomography and immunofluorescence staining. In addition, the effects of matrix metalloproteinase (MMP)-1 and MMP-8 production were investigated in human periodontal ligament (hPDL) cells in vitro. The expression of MMP-1 and MMP-8 was analyzed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Furthermore, we demonstrated the signaling pathways involved in relaxin-regulated MMPs expression. The relapse distances and percentages were significantly decreased in the experimental group compared with the controls in vivo. A double-immunofluorescence analysis for Col-I/MMP-1 and Col-I/MMP-8 detected the expression of relaxin in the PDL. Relaxin significantly increased the MMP-1 and MMP-8 expression in a time-dependent manner in hPDL cells in vitro. Furthermore, a p38 inhibitor (SB203580) significantly inhibited the MMP-1 and MMP-8 expression. Our results indicated that relaxin modulates the collagen metabolism, and this hormone may therefore be useful to prevent orthodontic relapse following orthodontic treatment.     

Changes in Pulmonary Circulation in Experimental Model of Pulmonary Thromboembolism after Carvedilol Treatment

Bulletin of Experimental Biology and Medicine - Changes in the blood cytokine profile in rats with various parameters of behavior were studied under conditions of 5-day starvation not followed by...     

Changes of Pulmonary Microhemodynamics in Experimental Pulmonary Thromboembolism after Pretreatment with K-Channel Activators

Bulletin of Experimental Biology and Medicine - Changes in pulmonary microhemodynamics in response to pulmonary embolism under conditions of activation of KATP channels with nicorandil, Kv channels...     

深部组织热物理参数的测量及其结果分析

本文阐述了用热干扰法测量机体组织热物性参数和灌注率的实现过程：把热敏电阻探头插入所需测量的组织，给热敏电阻供应电能使其温度升高达到预定值，所需电功率的大小与组织的热物性和血液灌注有关，通过建立热敏电阻珠和测量介质的耦合数学模型，得到计算导热率、扩散率和血液灌的表达式。本文首先用这种方法测量液体介质和离体介质的导热率来验证测量系统的准确性，然后用流动的液体模拟活体组织来测量流动介质的导热率和灌注率。实验结果表明：液体实验结果和离体实验结果与文献基本一致，流动液体的实验结果和我们的分析也完全吻合。