Fabrication of low surface free energy automotive clear coats: Mechanical and surface chemistry studies

This work aims at improving the surface chemistry and the mechanical properties of a commercial acrylic–melamine clear coat using a functional siliconized additive. The resistance of films against biological degradation was then investigated using pancreatin (simulated bird droppings) and Arabic gum (simulated tree gum). Variations in the surface and bulk chemical structures, as well as the thermomechanical characteristics of the clear coats at different concentrations of the additive, were investigated by a wide range of techniques inclusive of contact angle measurement, gonio‐spectrophotometery, dynamic mechanical thermal analysis (DMTA), energy‐dispersive spectroscopy, atomic force microscope, optical microscope, and attenuated totalreflectance Fourier transform infrared (ATR‐FTIR) spectroscopy. Negligible effect of additive on color change was revealed. It was shown that even at low loadings of additive it could migrate to the surface, producing hydrophobic films with very low surface free energies with water contact angle exceeding 100°. In addition, it was found by DMTA and ATR‐FTIR studies that the functional additive was covalently attached to the acrylic–melamine chains through its hydroxyl groups. However, phase separation was observed at high concentrations of additive, leading to reduced crosslinking density. The clear coat resistance against pancreatin and Arabic gum was improved using optimum concentrations of the additive. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Non-Coding RNAs in Stem Cell Regulation and Cardiac Regeneration: Current Problems and Future Perspectives

Although advances in rapid revascularization strategies following acute myocardial infarction (AMI) have led to improved short and long-term outcomes, the associated loss of cardiomyocytes and the subsequent remodeling result in an impaired ventricular function that can lead to heart failure or death. The poor regenerative capacity of the myocardium and the current lack of effective regenerative therapies have driven stem cell research in search of a possible solution. One approach involves the delivery of stem cells to the site of injury in order to stimulate repair response. Although animal studies initially delivered promising results, the application of similar techniques in humans has been hampered by poor target site retention and oncogenic considerations. In response, several alternative strategies, including the use of non-coding RNAs (ncRNAs), have been introduced with the aim of activating and regulating stem cells or inducing stem cell status in resident cells. Circular RNAs (circRNAs) and microRNAs (miRNAs) are ncRNAs with pivotal functions in cell proliferation and differentiation, whose role in stem cell regulation and potential significance for the field of cardiac regeneration is the primary focus of this review. We also address the general advantages of ncRNAs as promising drivers of cardiac regeneration and potent stem cell regulators.     

Altered DNA Methylation Profiles in SF3B1 Mutated CLL Patients

Mutations in splicing factor genes have a severe impact on the survival of cancer patients. Splicing factor 3b subunit 1 (SF3B1) is one of the most frequently mutated genes in chronic lymphocytic leukemia (CLL); patients carrying these mutations have a poor prognosis. Since the splicing machinery and the epigenome are closely interconnected, we investigated whether these alterations may affect the epigenomes of CLL patients. While an overall hypomethylation during CLL carcinogenesis has been observed, the interplay between the epigenetic stage of the originating B cells and SF3B1 mutations, and the subsequent effect of the mutations on methylation alterations in CLL, have not been investigated. We profiled the genome-wide DNA methylation patterns of 27 CLL patients with and without SF3B1 mutations and identified local decreases in methylation levels in SF3B1^mut CLL patients at 67 genomic regions, mostly in proximity to telomeric regions. These differentially methylated regions (DMRs) were enriched in gene bodies of cancer-related signaling genes, e.g., NOTCH1, HTRA3, and BCL9L. In our study, SF3B1 mutations exclusively emerged in two out of three epigenetic stages of the originating B cells. However, not all the DMRs could be associated with the methylation programming of B cells during development, suggesting that mutations in SF3B1 cause additional epigenetic aberrations during carcinogenesis.     

Fast spin-echo MR imaging of the eye

Magnetic resonance imaging of the eye usually includes T2-weighted images both for screening purposes and for characterization of melanoma. Conventional T2-weighted spin-echo (SE) imaging suffers both from long acquisition times and incomplete recovery of the vitreous' signal. A fast SE sequence was therefore compared prospectively with conventional sequences in 29 consecutive patients with lesions of the eye. Fast SE images delineated melanoma and other lesions of the eye from vitreous better than conventional T2-weighted images. Image quality and lesion conspicuity were improved on the fast sequence. Whereas melanoma appeared hypointense to vitreous on both types of images, subretinal effusion was hypointense on fast images and hyperintense on conventional T2-weighted images. Ghosting of the globe, which, however, did not decrease diagnostic value, was more pronounced on fast images. Conventional T2-weighted images may be replaced by fast SE images in MR studies of the eye with a gain in lesion conspicuity and significant time saving.     

Size effect in randomly loaded specimens

The theory of statistical size effect was used to determine the fatigue life of randomly loaded specimens of 7075 T7351 alloy. On the basis of tests with small specimens it is shown that the crack initiation life of larger components may be predicted using the theory, provided that the fatigue crack initiates from the surface and that the surface conditions of the laboratory specimen and component are technologically the same. For the two types of notched specimens tested, the predictions of fatigue life agree well with the test results.     

Pulsed 2‐Dimensional Raman Spectroscopy on Microdroplets

In this study, we used a technique based on pulsed Raman spectroscopy to determine the average concentration in the liquid phase and concentration distribution in the gas phase surrounding desorbing linear arrays of binary microdroplets. For this study, monodisperse microdroplets consisting of acetylene dissolved in acetone were generated by a modified vibrating orifice aerosol generator (VOAG). The 2‐dimensional concentration fields of acetylene desorbed from the droplets were determined with a spatial resolution of about 40 μm both along the direction of the droplet chain and perpendicular to it. The detection limits for the gas and liquid phase concentrations were about 100 ppm and 1 mmol/l, respectively.     

基于静态松弛的一种广义界面单元方法

根据静态松弛快速拉格朗日分析方法（Ｓ－ＦＬＡＣ）,提出一种求解岩体界面的新方法即广义界面单元方法,该方法可起初模拟界面的各种复杂变形。推导了相应公式,并给出了两个典型算例。     

“Empowering” Cardiac Cells via Stem Cell Derived Mitochondrial Transplantation- Does Age Matter?

With cardiovascular diseases affecting millions of patients, new treatment strategies are urgently needed. The use of stem cell based approaches has been investigated during the last decades and promising effects have been achieved. However, the beneficial effect of stem cells has been found to being partly due to paracrine functions by alterations of their microenvironment and so an interesting field of research, the “stem- less” approaches has emerged over the last years using or altering the microenvironment, for example, via deletion of senescent cells, application of micro RNAs or by modifying the cellular energy metabolism via targeting mitochondria. Using autologous muscle-derived mitochondria for transplantations into the affected tissues has resulted in promising reports of improvements of cardiac functions in vitro and in vivo. However, since the targeted treatment group represents mainly elderly or otherwise sick patients, it is unclear whether and to what extent autologous mitochondria would exert their beneficial effects in these cases. Stem cells might represent better sources for mitochondria and could enhance the effect of mitochondrial transplantations. Therefore in this review we aim to provide an overview on aging effects of stem cells and mitochondria which might be important for mitochondrial transplantation and to give an overview on the current state in this field together with considerations worthwhile for further investigations.