Spectral Labs (United States)

BackgroundCRISPR-Cas9 genome editing often induces unintended, large genomic rearrangements, posing potential safety risks. However, there are no methods for mitigating these risks.ResultsUsing long-read individual-molecule sequencing (IDMseq), we found the microhomology-mediated end joining (MMEJ) DNA repair pathway plays a predominant role in Cas9-induced large deletions (LDs). We targeted MMEJ-associated genes genetically and/or pharmacologically and analyzed Cas9-induced LDs at multiple gene loci using flow cytometry and long-read sequencing. Reducing POLQ levels or activity significantly decreases LDs, while depleting or overexpressing RPA increases or reduces LD frequency, respectively. Interestingly, small-molecule inhibition of POLQ and delivery of recombinant RPA proteins also dramatically promote homology-directed repair (HDR) at multiple disease-relevant gene loci in human pluripotent stem cells and hematopoietic progenitor cells.ConclusionsOur findings reveal the contrasting roles of RPA and POLQ in Cas9-induced LD and HDR, suggesting new strategies for safer and more precise genome editing.

The age of an individual is an essential demographic parameter but is difficult to estimate without long‐term monitoring or invasive sampling. Epigenetic approaches are increasingly used to age organisms, including nonmodel organisms such as cetaceans. Māui dolphins (Cephalorhynchus hectori maui) are a critically endangered subspecies endemic to Aotearoa New Zealand, and the age structure of this population is important for informing conservation. Here we present an epigenetic clock for aging Māui and Hector's dolphins (C. h. hectori) developed from methylation data using DNA from tooth aged individuals (n = 48). Based on this training data set, the optimal model required only eight methylation sites, provided an age correlation of .95, and had a median absolute age error of 1.54 years. A leave‐one‐out cross‐validation analysis with the same parameters resulted in an age correlation of .87 and median absolute age error of 2.09 years. To improve age estimation, we included previously published beluga whale (Delphinapterus leucas) data to develop a joint beluga/dolphin clock, resulting in a clock with comparable performance and improved estimation of older individuals. Application of the models to DNA from skin biopsy samples of living Māui dolphins revealed a shift from a median age of 8–9 years to a younger population aged 7–8 years 10 years later. These models could be applied to other dolphin species and demonstrate the ability to construct a clock even when the number of known age samples is limited, removing this impediment to estimating demographic parameters vital to the conservation of critically endangered species.

In order to create models of extended surfaces in the long and short wavelength parts of the wave spectrum, it is necessary to know the dispersion characteristics of tape-like obstacles perfectly located both in free space and on an extended surface. Methods of remote studying of extended surfaces, based on an analysis of signals that are generated by reflection or radiation of electromagnetic waves passing neoplasms allows us to view the topography, characteristics, and type of the different locations, sizes of various objects. One of the effective methods of study is to solve the problem of diffraction of electromagnetic waves on an infinitely extended object in free space. The purpose of this study is characteristics of electromagnetic waves during diffraction of electromagnetic waves at objects that can be used as radar systems. The method of statistical processing of experimental data from field tests and mathematical description of electromagnetic radar situation, as well as its computer simulation were used. The result of this study can be formulated as the development of analytical and software methods for analyzing diffraction pattern of electromagnetic waves in multi-wave mode of reception on infinitely extended object in free space, as well as a software method for calculating diffraction characteristics at frequencies exceeding the basic frequency, taking into account the inhomogeneity of electromagnetic fields in these conditions. The practical significance is the research results used in the development of a universal technique for design and development of radar systems capable of working adequately in conditions of electromagnetic environment in question. The results of this research will allow a complete description of the electrodynamic picture of wave propagation and its diffraction, namely, taking into account the diffraction properties of radar systems will allow us to develop a direction for their wider production and distribution.

The Static X-Ray Imager (SXI) is a National Ignition Facility (NIF) diagnostic that uses a CCDcamera to record timeintegrated X-ray images of target features such as the laser entrance hole of hohlraums. SXI has two dedicated positioners on the NIF target chamber for viewing thetarget from above and below, and the X-ray energies of interest are 870 eV for the “soft” channel and 3 – 5 keV for the “hard” channels. The original cameras utilize a large formatbackilluminated 2048 x 2048 CCD sensor with 24 micron pixels. Since the original sensor isno longer available, an effort was recently undertaken to build replacement cameras withsuitable new sensors. Three of the new cameras use a commercially available front-illuminatedCCD of similar size to the original, which has adequate sensitivity for the hard X-ray channelsbut not for the soft. For sensitivity below 1 keV, Lawrence Livermore National Laboratory (LLNL) had additional CCDs back-thinned andconverted to back-illumination for use in the other two new cameras. In this paper we describethe characteristics of the new cameras and present performance data (quantum efficiency, flat field, and dynamic range) for the front- and back-illuminated cameras, with comparisons to the originalcameras.

Ludwig-Maximilians-Universit¨at M¨unchen operates an astrophysical observatory on the summit of Mt. Wendelstein 1 which will be equipped with a modern 2m-class, robotic telescope. 2 One Nasmyth port of the new Fraunhofer telescope is designed to sustain the excellent (< 0.8 median) seeing of the site [1, Fig. 1] over a FOV of 0.2 deg 2 utilizing three-element transmissive field corrector optics for optical wavebands. It will be equipped with a camera built around a customized 64 MPixel Mosaic (Spectral Instruments, 4 × (4k) 2 15μm e2v CCDs). TheWendelsteinWide Field Imager has two filter wheels with eight slots each (SDSS3 [ugriz] + eight still free) as well as two off-axis guiding units (two FLI Microline with 2k Fairchild CCDs on differential focus stages). A Bonn Shutter4 ensures high precision photometric exposures. An option to either insert a low dispersion grating (for field spectroscopy) or support a wave front sensor probe allows for further expansion of the camera. EMI-safe housing has to overcome the emission of a close by 0.5MW radio station. Special care has been taken to design a very low ghost budget of the overall system to allow for low-surface brightness applications (e.g. weak lensing surveys).

Single stripe GaAs/AlGaAs, 4 μm wide real refractive index guided lasers are operated at powers up to 500 mW CW with total conversion efficiencies of 60%. Reliability studies of these lasers indicate an average lifetime of greater than 20000 h at 5°C at an operating power of 100 mW CW. The laser operates in a single transverse and longitudinal mode with a spectral linewidth of less than 6 MHz and a side mode suppression ratio of better than −30dB.