In November 2013 an International Key Comparison, CCM.G-K2, was organized in the Underground Laboratory for Geodynamics in Walferdange. The comparison has assembled 25 participants coming from 19 countries and four different continents. The comparison was divided into two parts: the key comparison that included 10 NMIs or DIs, and the pilot study including all participants. The global result given by the pilot study confirms that all instruments are absolutely coherent to each other. The results obtained for the key comparison confirm a good agreement between the NMI instruments. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A mobile atomic absolute gravimeter NIM-AGRb-1 based on light-pulse atom interferometer has been built, evaluated by the National Institute of Metrology (NIM) China, and participated in the pilot study of the International Comparison of Absolute Gravimeters (CCM.G-K2.2017) held at NIM Changping Beijing in October 2017. The sensitivity of the gravimeter is 44 µGal Hz −1/2 (1 µGal = 10 −8 m s −2 ≈ 10 −9 g) and its instability reaches as small as 0.2 µGal when averaged over 30 000 s. The instrumental and environmental effects were evaluated and corrected with a total uncertainty of 5.2 µGal. The absolute g measured by NIM-AGRb-1 was compared to that of a commercial FG5X-249 optical gravimeter with the two devices operating side by side in the same laboratory and their results agree within −0.2(6.3) µGal. NIM-AGRb-1 also demonstrated continuous operation over a period of more than 500 h.

A major hindrance in gene therapy trials with adeno-associated virus (AAV) vectors is the presence of neutralizing antibodies (NAbs) that inhibit AAV transduction. In this study, we used directed evolution techniques in vitro and in mouse muscle to select novel NAb escape AAV chimeric capsid mutants in the presence of individual patient serum. AAV mutants isolated in vitro escaped broad patient-specific NAb activity but had poor transduction ability in vivo. AAV mutants isolated in vivo had enhanced NAb evasion from cognate serum and had high muscle transduction ability. More importantly, structural modeling identified a 100 amino acid motif from AAV6 in variable region (VR) III that confers this enhanced muscle tropism. In addition, a predominantly AAV8 capsid beta barrel template with a specific preference for AAV1/AAV9 in VR VII located at threefold symmetry axis facilitates NAb escape. Our data strongly support that chimeric AAV capsids composed of modular and nonoverlapping domains from various serotypes are capable of evading patient-specific NAbs and have enhanced muscle transduction.

The CCM.G-K2.2017 comparison was organised for the purpose of determination of the degree of equivalence of the national standards for free-fall acceleration measurement. The comparison was held in the Changping Campus of National Institute of Metrology China (NIM), from October to November in 2017. This is the first time that such a comparison is organized outside of the Europe continent and establishes a new global comparison sites in China [1, 2]. This comparison is also the largest ever organized with the participation of 13 instruments. Dr. Shuqing Wu, Dr. Jinyang Feng and Mrs. Chunjian Li from the NIM were in charge of the local organization of the comparison and of the elaboration of the results. NIM was the Pilot Laboratory under the leadership of Dr. Shuqing Wu. The comparison steering committee (SC) is composed of Prof. Olivier Francis (LU), Dr. Vojtech Pálinkáš (VÚGTK/RIGTC), Dr. Derek van Westrum (NOAA-NGS), Dr. Reinhard Falk (BKG) and Dr. Shuqing Wu (NIM). The SC is supported and consulted by the CCM-WGG Chair, Prof. Alessandro Germak (INRIM). The comparison was organized in accordance with the CIPM MRA-D-05 of the Consultative Committee on Mass and Related Quantities (CCM).

The International Comparison of Absolute Gravimeters 2009 (ICAG2009) was carried out in September 2009 at the International Bureau of Weights and Measures (BIPM). The ICAG2009 and its data processing were performed in accordance with the agreed Technical Protocol which was approved by the Steering Committee. The pilot laboratory (BIPM) evaluated the final results of the key comparison from the measurements made at the BIPM in the framework of ICAG2009. A pilot study run in parallel allowed evaluation of the offsets for absolute gravimeters from institutes not fulfilling the requirements for participating in the key comparison. The gravity values at the five stations, and the offsets for each absolute gravimeter, were obtained by a weighted least squares fit. The results indicate that all participating gravimeters are consistent within their expanded uncertainties.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

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A novel staining method and the associated fluorescent dye were developed for protein analysis by capillary SDS-PAGE. The method strategy is to synthesize a pseudo-SDS dye and use it to replace some of the SDS in SDS-protein complexes so that the protein can be fluorescently detected. The pseudo-SDS dye consists of a long, straight alkyl chain connected to a negative charged fluorescent head and binds to proteins just as SDS. The number of dye molecules incorporated with a protein depends on the dye concentration relative to SDS in the sample solution, since SDS and dye bind to proteins competitively. In this work, we synthesized a series of pseudo-SDS dyes, and tested their performances for capillary SDS-PAGE. FT-16 (a fluorescein molecule linked with a hexadodecyl group) seemed to be the best among all the dyes tested. Although the numbers of dye molecules bound to proteins (and the fluorescence signals from these protein complexes) were maximized in the absence of SDS, high-quality separations were obtained when co-complexes of SDS-proteindye were formed. The migration time correlates well with protein size even after some of the SDS in the SDS-protein complexes was replaced by the pseudo-SDS dye. Under optimized experimental conditions and using a laser-induced fluorescence detector, limits of detection of as low as 0.13 ng/ mL (bovine serum albumin) and dynamic ranges over 5 orders of magnitude in which fluorescence response is proportional to the square root of analyte concentration were obtained. The method and dye were also tested for separations of real-world samples from E. coli.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is one of the most commonly used methods for protein analysis. Usually, a staining and destaining process is involved in order to properly detect the separated protein bands. Capillary electrophoresis (CE), and more recently microchip-based electrophoresis, is a miniaturized electrophoresis technique that has many advantages (e.g., high separation efficiency, short separation time, low mass detection limit, on-line detection, and automated operation) over traditional slab gel techniques. SDS-PAGE has been performed in capillaries 1-5 and on microchips. 6-9 Unfortunately, the staining and destaining process used in conventional slab gels cannot be simply adopted in CE. Typically, the separated proteins are detected in-column by either an ultraviolet (UV) absorbance or a laser-induced fluorescence (LIF) detection system. UV absorption is arguably the most frequently used detection mode in CE. It is also commonly employed in capillary SDS-PAGE, 1,2 since protein-SDS complexes absorbs light around 280 nm due to the aromatic side groups of amino acids and around 200−220 nm due to the peptide bonds between amino acids. LIF detection is preferred when low limit of detection (LOD) and wide linear dynamic range are desired. Native fluorescence of proteins has been explored for direct protein detection, 10 but it is not widely accepted because of the use of expe...