Exploring public perceptions of creating and using 3D printed human remains

3D printed human remains offer an alternative presentation format to traditional photographs, that could be more effective and less emotive. However, the perception of the public regarding key questions, such as the use, ownership, and disposal of 3D printed remains in courts of law has not yet been established. This study explored whether the creation of 3D printed human remains could be considered as an ethical practice by members of the public. A survey comprised of 36 questions was designed to gather responses from members of the public (n = 400) about their attitudes to the creation and use of 3D printed human remains. A majority of respondents believed it was ethical to use 3D prints in courtroom demonstrations (more than 90%) and that this may help jurors to better understand expert testimony over photographs. Respondents also indicated that the context of the case and whether consent had been received from next of kin were important considerations. The results of this study indicate that there is a recognition that there is a direct connection between 3D printed remains and the individual from whom a print derives, and that there is a clear public interest in ensuring that prints are used ethically and responsibly. Yet there are currently no guidelines for what constitutes best ethical practice for the creation and utilisation of 3D prints. As we look forward, there is a need to identify how best to treat 3D printed remains with dignity and respect in casework in a manner that is also contextually appropriate

Effects of larval density on gene regulation in C. elegans during routine L1 synchronization [preprint]

Bleaching gravid C. elegans followed by a short period of starvation of the L1 larvae is a routine method performed by worm researchers for generating synchronous populations for experiments. During the process of investigating dietary effects on gene regulation in L1 stage worms by single-worm RNA-Seq, we found that the density of resuspended L1 larvae affects expression of many mRNAs. Specifically, a number of genes related to metabolism and signalling are highly expressed in worms arrested at low density, but are repressed at higher arrest densities. We generated a GFP reporter strain based on one of the most density-dependent genes in our dataset – lips-15 – and confirmed that this reporter was expressed specifically in worms arrested at relatively low density. Finally, we show that conditioned media from high density L1 cultures was able to downregulate lips-15 even in L1 animals arrested at low density, and experiments using the daf-22 mutant demonstrated that this effect is not mediated by the ascaroside family of signalling pheromones. Together, our data implicate a soluble signalling molecule in density sensing by L1 stage C. elegans, and provide guidance for design of experiments focused on early developmental gene regulation

Flexibility and constraint in preimplantation gene regulation in mouse [preprint]

Although many features of embryonic development exhibit remarkable stability in the face of environmental perturbations, it is also clear that some aspects of early embryogenesis can be modulated by non-genetic influences during and after fertilization. Among potential perturbations experienced during reproduction, understanding the consequences of differing ex vivo fertilization methods at a molecular level is imperative for comprehending both the basic biology of early development and the potential consequences of assisted reproduction. Here, we set out to explore stable and flexible aspects of preimplantation gene expression using single-embryo RNA-sequencing of mouse embryos fertilized by natural mating, in vitro fertilization, or intracytoplasmic sperm injection, as well as oocytes parthenogenetically activated to develop (parthenotes). This dataset comprises a resource of over eight hundred individual embryos, which we use for three primary analyses. First, we characterize the effects of each fertilization method on early embryonic gene regulation, most notably finding decreased expression of trophectoderm markers at later stages of preimplantation development in ICSI embryos. Second, we find massive gene misregulation in parthenotes beyond the expected defects in imprinted gene expression, and show that many of these changes can be suppressed by sperm total RNA. Finally, we make use of the single-embryo resolution of our dataset to identify both stably-expressed genes and highly-variable genes in the early mouse embryo. Together, our data provide a detailed survey of the molecular consequences of different fertilization methods, establish parthenotes as a “tabula rasa” for understanding the role for sperm RNAs in preimplantation gene regulation, and identify subtypes of preimplantation embryos based on their expression of epivariable gene modules

Cytosine methylation dynamics during post-testicular sperm maturation in mammals [preprint]

Beyond the haploid genome, mammalian sperm contribute a payload of epigenetic information which can modulate offspring phenotypes. Recent studies have shown that the small RNA payload of sperm undergoes extensive remodeling during post-testicular maturation in the epididymis. Intriguingly, epididymal maturation has also been linked to changes in the sperm methylome, suggesting that the epididymis might play a broader role in remodeling the sperm epigenome. Here, we build on prior studies of the maturing sperm methylation landscape, further characterizing the genome-wide methylation landscape in seven germ cell populations collected from throughout the male reproductive tract. Overall, we find very few changes in the cytosine methylation landscape between testicular germ cell populations and cauda epididymal sperm, demonstrating that the sperm methylome is largely stable throughout post-testicular maturation. Intriguingly, although our sequencing data suggested that caput epididymal sperm exhibit a highly unusual methylome, follow-up studies revealed that this resulted from contamination of caput sperm by extracellular DNA. Extracellular DNA formed web-like structures that ensnared sperm, was present only in the caput epididymis of virgin males, where it was associated with citrullinated histone H3 and presumably resulted from a PAD-driven genome decondensation process. Taken together, our data emphasize the stability of the cytosine methylation landscape in mammalian sperm, and identify a surprising but transient period during which immature sperm are associated with extracellular DNA

Suppression of pervasive noncoding transcription in embryonic stem cells by esBAF

Approximately 75% of the human genome is transcribed, the majority of which does not encode protein. However, many noncoding RNAs (ncRNAs) are rapidly degraded after transcription, and relatively few have established functions, questioning the significance of this observation. Here we show that esBAF, a SWI/SNF family nucleosome remodeling factor, suppresses transcription of ncRNAs from approximately 57,000 nucleosome-depleted regions (NDRs) throughout the genome of mouse embryonic stem cells (ESCs). We show that esBAF functions to both keep NDRs nucleosome-free and promote elevated nucleosome occupancy adjacent to NDRs. Reduction of adjacent nucleosome occupancy upon esBAF depletion is strongly correlated with ncRNA expression, suggesting that flanking nucleosomes form a barrier to pervasive transcription. Upon forcing nucleosome occupancy near two NDRs using a nucleosome-positioning sequence, we found that esBAF is no longer required to silence transcription. Therefore, esBAF\u27s function to enforce nucleosome occupancy adjacent to NDRs, and not its function to maintain NDRs in a nucleosome-free state, is necessary for silencing transcription over ncDNA. Finally, we show that the ability of a strongly positioned nucleosome to repress ncRNA depends on its translational positioning. These data reveal a novel role for esBAF in suppressing pervasive transcription from open chromatin regions in ESCs

Dynamics of nonequilibrium quasiparticles in a double superconducting tunnel junction detector

We study a class of superconductive radiation detectors in which the absorption of energy occurs in a long superconductive strip while the redout stage is provided by superconductive tunnel junctions positioned at the two ends of the strip. Such a device is capable both of imaging and energy resolution. In the established current scheme, well studied from the theoretical and experimental point of view, a fundamental ingredient is considered the presence of traps, or regions adjacent to the junctions made of a superconducting material of lower gap. We reconsider the problem by investigating the dynamics of the radiation induced excess quasiparticles in a simpler device, i.e. one without traps. The nonequilibrium excess quasiparticles can be seen to obey a diffusion equation whose coefficients are discontinuous functions of the position. Based on the analytical solution to this equation, we follow the dynamics of the quasiparticles in the device, predict the signal formation of the detector and discuss the potentiality offered by this configuration.Comment: 16 pages, 5 figures Submitted to Superconducting Science and Technolog

STJ Observations of the Eclipsing Polar HU Aqr

We apply an eclipse mapping technique to observations of the eclipsing magnetic cataclysmic variable HU Aqr. The observations were made with the S-Cam2 Superconducting Tunnel Junction detector at the WHT in October 2000, providing high signal-to-noise observations with simultaneous spectral and temporal resolution. HU Aqr was in a bright (high accretion) state (V=14.7) and the stream contributes as much to the overall system brightness as the accretion region on the white dwarf. The stream is modelled assuming accretion is occuring onto only one pole of the white dwarf. We find enhanced brightness towards the accretion region from irradiation and interpret enhanced brightness in the threading region, where the ballistic stream is redirected to follow the magnetic field lines of the white dwarf, as magnetic heating from the stream-field interaction, which is consistent with recent theoretical results. Changes in the stream eclipse profile over one orbital period indicate that the magnetic heating process is unstable.Comment: Accepted for publication in MNRAS (11 pages

Direct determination of quasar redshifts

We present observations of 11 quasars, selected in the range z = 2.2-4.1, obtained with ESA's Superconducting Tunnel Junction (STJ) camera on the WHT. Using a single template quasar spectrum, we show that we can determine the redshifts of these objects to about 1%. A follow-up spectroscopic observation of one QSO for which our best-fit redshift (z = 2.976) differs significantly from the tentative literature value (z ~ 2.30) confirms that the latter was incorrect.Comment: 4 pages, 3 figures; uses aa.cls, psfig.sty, natbib.sty; accepted for publication in A&A Letter

Critical Review of Methods for Sampling, Analysis, and Monitoring of Vapor-Phase Toluene Diisocyanate

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91959/1/TLVpaper2002.pd

Fermi-LAT Observations and A Broadband Study of Supernova Remnant CTB 109

CTB 109 (G109.1-1.0) is a Galactic supernova remnant (SNR) with a hemispherical shell morphology in X-rays and in the radio band. In this work we report the detection of {\gamma}-ray emission coincident with CTB 109, using 37 months of data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. We study the broadband characteristics of the remnant using a model that includes hydrodynamics, efficient cosmic ray acceleration, nonthermal emission and a self-consistent calculation of the X-ray thermal emission. We find that the observations can be successfully fit with two distinct parameter sets, one where the {\gamma}-ray emission is produced primarily by leptons accelerated at the SNR forward shock and the other where {\gamma}-rays produced by forward shock accelerated cosmic-ray ions dominate the high-energy emission. Consideration of thermal X-ray emission introduces a novel element to the broadband fitting process, and while it does not rule out either the leptonic or the hadronic scenarios, it constrains the parameter sets required by the model to fit the observations. Moreover, the model which best fits the thermal and nonthermal emission observations is an intermediate case, where both radiation from accelerated electrons and hadrons contribute almost equally to the {\gamma}-ray flux observed.Comment: 10 pages, 6 figures. Accepted for publication in Ap