Getreide, Getreideerzeugnisse u. dgl.

Ohne Zusammenfassung     

Mirror fixation

A mirror is the ideal fixation device for an ophthalmoscopic examination: it is the essense of simplicity, and there is nothing the patient would rather watch than himself.     

机器人三维可视化离线编程和仿真系统

提出了一种基于PC的交互式三维可视化离线编程和动态仿真系统。利用目前流行的PC机和Windows操作系统所支持的OpenGL三维图形功能,在系统中实现了焊接机器人及其工件的三维几何建模和机器人运动学建模,并研究了机器人运动轨迹的自动规划和编程以及它的图形化三维动态仿真。采用交互式三维“虚拟示教”方式实现了机器人单道焊焊接路径的规划和编程,对多层多道焊,则通过采用“宏”技术实现机器人焊接运动轨迹的自动规划和编程,通过图形化三维动态仿真实现了对机器人程序及运动轨迹的可靠性和安全性验证。离线编制的程序在向机器人控制系统传送的过程中实现了向机器人语言的自动转换,从而使机器人离线编程的实用性得到大大提高。     

Terpolymers from lactide and bisphenol a derivatives: Scale‐up,properties, and blends

Terpolymerization of L‐lactide (LA) and bisphenol A derivatives was performed on few hundred gram scale, and the resultant terpolymer (TP) was characterized by gel permeation chromatography, infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis. Moderate molecular weight (M_n ～ 12 kg/mol) TP was achieved with glass transition temperatures about 100°C (DSC and DMA). The TP exhibited improved thermal stability compared with polylactide (PLA), with a thermal degradation temperature of about 80°C higher than PLA. Although the TP exhibited distinctly different surface morphology compared with that of PLA, both showed similar contact angle and surface energy (ca. 40 mN/m) properties. Blends of PLA and TP showed enhanced glass transition (～ 5°C change in T_g) temperatures compared with PLA homopolymer. This is due to the compatibility of PLA and TP. Thus, TP could be used as an additive for PLA‐based blends to enhance compatibility with phenolic‐based resins. TP electrospun fiber morphology is also reported. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

In vivo biocompatibility and biostability of modified polyurethanes

Modified segmented polyurethanes were examined for biostability and biocompatibility using an in vivo cage implant system for time intervals of 1, 2, 3, 5, and 10 weeks. Two types of materials were used: polyether polyurethanes and polycarbonate polyurethanes. Two unmodified polyether polyurethanes (PEUU A' and SPU-PRM), one PDMS endcapped polyether polyurethane (SPU-S), and two polycarbonate polyurethanes (SPU-PCU and SPU-C) were investigated in this study. Techniques used to characterize untreated materials were dynamic water contact angle, stress-strain analysis, and gel permeation chromatography. Cellular response was measured by exudate analysis and by macrophage and foreign body giant cell (FBGC) densities. Material characterization, postimplantation, was done by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) in order to quantify biodegradation and scanning electron microscopy (SEM) to qualitatively describe the cellular response and biodegradation. The exudate analysis showed that the acute and chronic inflammatory responses for all materials were similar. Lower FBGC densities and cell coverage on SPU-S were attributed to the hydrophobic surface provided by the PDMS endgroups. The polycarbonate polyurethanes did not show any significant differences in cell coverage or FBGC densities even though the macrophage densities were slightly lower compared to polyether polyurethanes. By 10 weeks, biodegradation in the case of PEUU A' and SPU-PRM was extensive as compared to SPU-S because the PDMS endcaps of SPU-S provided a shield against the oxygen radicals secreted by macrophages and FBGCs and lowered the rate of biodegradation. In the case of polycarbonate polyurethanes, the oxidative stability of the carbonate linkage lowered the rate of biodegradation tremendously as compared to the polyether polyurethanes (including SPU-S). The minor amount of biodegradation seen in polycarbonate polyurethanes at 10 weeks was attributed to hydrolysis of the carbonate linkage.     

Isolation and characterization of rat liver amphisomes. Evidence for fusion of autophagosomes with both early and late endosomes

Amphisomes, the autophagic vacuoles (AVs) formed upon fusion between autophagosomes and endosomes, have so far only been characterized in indirect, functional terms. To enable a physical distinction between autophagosomes and amphisomes, the latter were selectively density-shifted in sucrose gradients following fusion with AOM-gold-loaded endosomes (endosomes made dense by asialoorosomucoid-conjugated gold particles, endocytosed by isolated rat hepatocytes prior to subcellular fractionation). Whereas amphisomes, by this criterion, accounted for only a minor fraction of the AVs in control hepatocytes, treatment of the cells with leupeptin (an inhibitor of lysosomal protein degradation) caused an accumulation of amphisomes to about one-half of the AV population. A quantitative electron microscopic study confirmed that leupeptin induced a severalfold increase in the number of hepatocytic amphisomes (recognized by their gold particle contents; otherwise, their ultrastructure was quite similar to autophagosomes). Leupeptin caused, furthermore, a selective retention of endocytosed AOM-gold in the amphisomes at the expense of the lysosomes, consistent with an inhibition of amphisome-lysosome fusion. The electron micrographs suggested that autophagosomes could undergo multiple independent fusions, with multivesicular (late) endosomes to form amphisomes and with small lysosomes to form large autolysosomes. A biochemical comparison between autophagosomes and amphisomes, purified by a novel procedure, showed that the amphisomes were enriched in early endosome markers (the asialoglycoprotein receptor and the early endosome-associated protein 1) as well as in a late endosome marker (the cation-independent mannose 6-phosphate receptor). Amphisomes would thus seem to be capable of receiving inputs both from early and late endosomes.     

Non-autonomy of AGAMOUS function in flower development: use of a Cre/loxP method for mosaic analysis in Arabidopsis

Angiosperms use a multi-layered meristem (typically L1, L2 and L3) to produce primordia that then develop into plant organs. A number of experiments show that communication between the cell layers is important for normal development. We examined whether the function of the flower developmental control gene AGAMOUS involves communication across these layers. We developed a mosaic strategy using the Cre/loxP site-specific recombinase system, and identified the sector structure for mosaics that produced mutant flowers. The major conclusions were that (1) AGAMOUS must be active in the L2 for staminoid and carpelloid tissues, (2) that AGAMOUS must be active in the L2 and the L3 for floral meristem determinacy, and (3) that epidermal cell identity can be communicated by the L2 to the L1 layer.     

Preservation of the stapedius tendon in laser stapes surgery

OBJECTIVES/HYPOTHESIS: The stapedius tendon is routinely transected during stapes surgery. The objective of this study was to evaluate the technique of stapedial tendon preservation during stapes surgery and to compare results of these cases with cases where the stapedial tendon was not preserved. STUDY DESIGN: Retrospective study. METHODS: Four groups of patients were evaluated. Two groups had undergone stapes surgery with preservation of the stapedial tendon. One of these groups underwent a laser stapedotomy minus prosthesis (laser STAMP) procedure, while the other group had a prosthesis inserted. The other two groups had undergone laser stapedotomy with one of two different prostheses being used. Audiometric data were obtained and reviewed both preoperatively and at approximately 6 weeks postoperatively. RESULTS: All groups had overall successful results demonstrating that stapedial tendon preservation is technically possible and does not compromise outcomes. CONCLUSIONS: Based on the results, it is recommended that the stapedius tendon be preserved whenever possible during laser stapes surgery. Reasons justifying its preservation are discussed.