Evaluation of Virus Inactivation by Formaldehyde to Enhance Biosafety of Diagnostic Electron Microscopy

Formaldehyde (FA) fixation of infectious samples is a well-established protocol in diagnostic electron microscopy of viruses. However, published experimental data that demonstrate virus inactivation by these fixation procedures are lacking. Usually, fixation is performed immediately before the sample preparation for microscopy. The fixation procedure should transform viruses in a non–infectious but nonetheless structurally intact form in order to allow a proper diagnosis based on morphology. FA provides an essential advantage in comparison to other disinfectants, because it preserves the ultrastructure of biological material without interfering significantly with the preparation (i.e., the negative staining) and the detection of viruses. To examine the efficiency of FA inactivation, we used Vaccinia virus, Human adenovirus and Murine norovirus as models and treated them with FA under various conditions. Critical parameters for the inactivation efficiency were the temperature, the duration of the FA treatment, and the resistance of the virus in question. Our results show that FA inactivation at low temperature (4 °C) bears a high risk of incomplete inactivation. Higher temperatures (25 °C) are more efficient, although they still require rather long incubation times to fully inactivate a complex and highly robust virus like Vaccinia. A protocol, which applied 2% buffered FA for 60 min and a temperature–shift from 25 to 37 °C after 30 min was efficient for the complete inactivation of all test viruses, and therefore has the potential to improve both biosafety and speed of diagnostic electron microscopy

Improved performance of CSD-grown Y1-xGdxBa2Cu3O7-BaHfO3 nanocomposite films on Ni5W substrates

Y1-xGdxBa2Cu3O7-BaHfO3 (YGBCO-BHO) nanocomposite films containing 12 & x00A0;mol & x0025; BHO nanoparticles and different amounts of Gd, x, were grown by Chemical Solution Deposition (CSD) on Ni5W substrates in order to investigate the impact of the rare-earth stoichiometry on the structure and superconducting properties of these films. For Gd contents x > 0.5, epitaxial YGBCO-BHO films with an approximate thickness of 270 & x00A0;nm self-field critical current density Jc at 77 & x00A0;K & x223C; 1,5 & x00A0;MA & x002F;cm & x00B2; were obtained. The field dependence of the critical current density Jc(B) shows a much larger accommodation field and lower exponents & x03B1; in Jc & x223C; B(& x2212;& x03B1;) values compared to pristine YBCO films. This is both due to the high amount of individual nanoparticles in the matrix as observed in TEM images and the higher critical temperatures Tc. The results show that the CSD is a potential candidate for the preparation of REBCO films in long-length coated conductors

Integration of e-beam direct write in BEOL processes of 28nm SRAM technology node using mix and match

Many efforts were spent in the development of EUV technologies, but from a customer point of view EUV is still behind expectations. In parallel since years maskless lithography is included in the ITRS roadmap wherein multi electron beam direct patterning is considered as an alternative or complementary approach for patterning of advanced technology nodes. The process of multi beam exposures can be emulated by single beam technologies available in the field. While variable shape-beam direct writers are already used for niche applications, the integration capability of e-beam direct write at advanced nodes has not been proven, yet. In this study the e-beam lithography was implemented in the BEoL processes of the 28nm SRAM technology. Integrated 300mm wafers with a 28nm back-end of line (BEoL) stack from GLOBALFOUNDRIES, Dresden, were used for the experiments. For the patterning of the Metal layer a Mix and Match concept based on the sequence litho - etch - litho – etch (LELE) was developed and evaluated wherein several exposure fields were blanked out during the optical exposure. E-beam patterning results of BEoL Metal and Via layers are presented using a 50kV VISTEC SB3050DW variable shaped electron beam direct writer at Fraunhofer IPMS-CNT. Etch results are shown and compared to the POR. In summary we demonstrate the integration capability of EBDW into a productive CMOS process flow at the example of the 28nm SRAM technology node

Polysialic Acid on Neuropilin-2 Is Exclusively Synthesized by the Polysialyltransferase ST8SiaIV and Attached to Mucin-type O-Glycans Located between the b2 and c Domain

Neuropilin-2 (NRP2) is well known as a co-receptor for class 3 semaphorins and vascular endothelial growth factors, involved in axon guidance and angiogenesis. Moreover, NRP2 was shown to promote chemotactic migration of human monocyte-derived dendritic cells (DCs) toward the chemokine CCL21, a function that relies on the presence of polysialic acid (polySia). In vertebrates, this posttranslational modification is predominantly found on the neural cell adhesion molecule (NCAM), where it is synthesized on N-glycans by either of the two polysialyltransferases, ST8SiaII or ST8SiaIV. In contrast to NCAM, little is known on the biosynthesis of polySia on NRP2. Here we identified the polySia attachment sites and demonstrate that NRP2 is recognized only by ST8SiaIV. Although polySia-NRP2 was found on bone marrow-derived DCs from wild-type and St8sia2(−/−) mice, polySia was completely lost in DCs from St8sia4(−/−) mice despite normal NRP2 expression. In COS-7 cells, co-expression of NRP2 with ST8SiaIV but not ST8SiaII resulted in the formation of polySia-NRP2, highlighting distinct acceptor specificities of the two polysialyltransferases. Notably, ST8SiaIV synthesized polySia selectively on a NRP2 glycoform that was characterized by the presence of sialylated core 1 and core 2 O-glycans. Based on a comprehensive site-directed mutagenesis study, we localized the polySia attachment sites to an O-glycan cluster located in the linker region between b2 and c domain. Combined alanine exchange of Thr-607, -613, -614, -615, -619, and -624 efficiently blocked polysialylation. Restoration of single sites only partially rescued polysialylation, suggesting that within this cluster, polySia is attached to more than one site

Large and deep perialpine lakes: a paleolimnological perspective for the advance of ecosystem science

Large perialpine lakes represent important components of the Alpine landscape. Due to their piedmont location in the most densely populated regions of the Alps, they play a crucial socio-economic role as resource for drinking water, irrigation, industry, tourism, hydroelectric production, and biodiversity conservation. These uses expose perialpine lakes to multiple human pressure, while the extension of their catchment to the glacial Alpine range make them particularly exposed to the consequences of global warming. Limnological surveys outlined coherent responses by perialpine lakes to the massive nutrient enrichment during the 1950s-1970s, while recent development is rather heterogeneous. Past and ongoing paleolimnological studies confirmed the coherence of the lakes’ evolution within a secular perspective, but outlined individual trends as resulting from local management policies, lake morphology, and superimposed effects of climate change. A review of the paleolimnological literature published from 1975 to April 2017on perialpine lakes of different lake districts north and south of the Alps, was performed aiming at reviewing current knowledge of large and deep perialpine lakes due to sediment studies, and at summarizing how paleolimnological studies can contribute in defining past ecological status and in outlining lake sensitivity to current and future human impacts. This is particularly important when defining reference conditions, as inappropriate restoration targets might prove to become unachievable within the present context of global change. The review outlined an heterogeneous distribution of amount and topics of sediment studies among perialpine lake districts as well as knowledge gaps on the long term evolution of perialpine lakes