Synthesis of Tritium Labeled Queuine, PreQ1 and Related Azide Probes Toward Examining the Prevalence of Queuine.

Queuine is a modified nucleotide known to occur in the anticodon of four tRNAs. The queuine modification occurs across all eukaryotes and eubacteria with few exceptions, but its function remains unclear. Prior in vitro work demonstrated that the modification can be incorporated into RNA species other than presently known tRNAs. Queuine is unusual in that, unlike the majority of modified nucleotides that result from changes to genetically encoded bases, it is incorporated into RNA by transglycosylation. Base modification by transglycosylation is unusual and represents an interesting point of entry for study. Due to this method of incorporation the modification can be studied with small molecule probes. Tritium-labeled queuine and preQ1 were prepared to study the differences between the eukaryotic and eubacterial version of the enzyme responsible for the incorporation of queuine, tRNA guanine transglycosylase. A concise, convergent synthesis of queuine was developed that is the shortest route to date. PreQ1, the precursor to queuine incorporated by eubacteria, was used to investigate the prevalence of base modification in E. coli. Three cell lines were utilized to conduct the in vivo experiments of this study: a ΔqueC knockout of E. coli that is unable to synthesize preQ1 so that labeled compound would be incorporated exclusively, a Δtgt knockout strain of E. coli that is unable to incorporate preQ1 and a wild-type E. coli strain. As the modified nucleotide occurs through incorporation of a specially synthesized nucleotide, a study of the sites of modification by prepared probes is possible. The syntheses of two novel azide congeners were undertaken for this purpose. The evaluation of their interaction with tRNA guanine transglycosylase was undertaken to determine if they are substrates of the enzyme. The tritium labeled preQ1 allowed for a general evaluation of the prevalence. That determined the four known tRNAs are the main site of incorporation in vivo, while many other RNAs are substrates in vitro. The azide probes were generated and interact with E. coli TGT, but were not substrates. In summary, we have gained a better understanding of queuine modification of RNAs and have developed tools that will aide in future studies.Ph.D.Medicinal ChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91387/1/afb_1.pd

Automated synthesis of PET radiotracers by copperâ mediated 18Fâ fluorination of organoborons: Importance of the order of addition and competing protodeborylation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142980/1/jlcr3583_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142980/2/jlcr3583.pd

The role of pre-event canopy storage in throughfall and stemflow by using isotopic tracers

Stable isotopes can be a valuable tool for tracing the redistribution, storage, and evaporation of water associated with canopy interception of rainfall. Isotopic differences between throughfall and rainfall have been attributed to three mechanisms: evaporative fractionation, isotopic exchange with ambient vapor, and temporal redistribution. We demonstrate the potential importance of a fourth mechanism: rainfall mixing with water retained within the canopy (in bark, epiphytes, etc.) from prior rain events. Amount and isotopic composition (¹⁸O and ²H) of rainfall and throughfall were measured over a 3-month period in a Douglas-fir forest in the Cascade Range of Oregon, USA. The range of spatial variability of throughfall isotopic composition exceeded the differences between event-mean isotopic compositions of rainfall and throughfall. Inter-event isotopic variation of precipitation was high and correlated with the isotopic deviation of throughfall from rainfall, likely related to a high canopy/bark storage capacity storage bridging events. Both spatial variability of throughfall isotopic composition and throughfall–precipitation isotopic differences appear to have been controlled by the temporally varying influence of residual precipitation from previous events. Therefore, isotopic heterogeneity could indicate local storage characteristics and the partitioning of flow-paths within the canopy.Keywords: stable isotope tracers, temporal stability, canopy storage, rainfall interception, spatial heterogeneit

Influence of Nanoparticle Size and Shape on Oligomer Formation of an Amyloidogenic Peptide

Understanding the influence of macromolecular crowding and nanoparticles on the formation of in-register $\beta$-sheets, the primary structural component of amyloid fibrils, is a first step towards describing \emph{in vivo} protein aggregation and interactions between synthetic materials and proteins. Using all atom molecular simulations in implicit solvent we illustrate the effects of nanoparticle size, shape, and volume fraction on oligomer formation of an amyloidogenic peptide from the transthyretin protein. Surprisingly, we find that inert spherical crowding particles destabilize in-register $\beta$-sheets formed by dimers while stabilizing $\beta$-sheets comprised of trimers and tetramers. As the radius of the nanoparticle increases crowding effects decrease, implying smaller crowding particles have the largest influence on the earliest amyloid species. We explain these results using a theory based on the depletion effect. Finally, we show that spherocylindrical crowders destabilize the ordered $\beta$-sheet dimer to a greater extent than spherical crowders, which underscores the influence of nanoparticle shape on protein aggregation

Effectiveness of a structured educational intervention using psychological delivery methods in children and adolescents with poorly controlled type 1 diabetes: a cluster randomised controlled trial of the CASCADE intervention

Introduction: Type 1 diabetes in children and adolescents is increasing worldwide with a particular increase in children < 5 years. Fewer than one in six children and adolescents achieve recommended HbA1c values. Methods: A pragmatic, cluster randomised control trial assessed the efficacy of a clinic-based structured educational group incorporating psychological approaches to improve long-term glycaemic control, quality of life and psychosocial functioning in children and adolescents with T1D. 28 paediatric diabetes services were randomised to deliver the intervention or standard care. 362 children (8-16 years) HbA1c ≥ 8.5% were recruited. Outcomes were HbA1c at 12 and 24 months, hypoglycaemia, admissions, self-management skills, intervention compliance, emotional and behavioural adjustment and quality of life. A process evaluation collected data from key stakeholder groups in order to evaluate the feasibility of delivering the intervention. Results: 298/362 patients (82.3%) provided HbA1c at 12 months and 284/362 (78.5%) at 24 months. The intervention did not improve HbA1c at 12 months (intervention effect 0.11, 95% CI −0.28 to 0.50, P=0.584), or 24 months (intervention effect 0.03, 95% CI -0.36 to 0.41, P=0.891). There were no significant changes in remaining outcomes. 96/180 (53%) families in the intervention arm attended at least one module. The number of modules attended did not affect outcome. Reasons for low uptake included difficulties organising groups and work and school commitments. Those with highest HbA1cs were less likely to attend. Mean cost of the intervention was £683 per child. Conclusions: Significant challenges in the delivery of a structured education intervention using psychological techniques to enhance engagement and behaviour change delivered by diabetes nurses and dietitians in routine clinical practice were found. The intervention did not improve HbA1c in children and adolescents with poor control

An exact expression to calculate the derivatives of position-dependent observables in molecular simulations with flexible constraints

In this work, we introduce an algorithm to compute the derivatives of physical observables along the constrained subspace when flexible constraints are imposed on the system (i.e., constraints in which the hard coordinates are fixed to configuration-dependent values). The presented scheme is exact, it does not contain any tunable parameter, and it only requires the calculation and inversion of a sub-block of the Hessian matrix of second derivatives of the function through which the constraints are defined. We also present a practical application to the case in which the sought observables are the Euclidean coordinates of complex molecular systems, and the function whose minimization defines the constraints is the potential energy. Finally, and in order to validate the method, which, as far as we are aware, is the first of its kind in the literature, we compare it to the natural and straightforward finite-differences approach in three molecules of biological relevance: methanol, N-methyl-acetamide and a tri-glycine peptideComment: 13 pages, 8 figures, published versio

Analysis of the dust evolution in the circumstellar disks of TTauri stars

We present a compositional analysis of 8-13um spectra of 32 young stellar objects (YSOs). Our sample consists of 5 intermediate-mass stars and 27 low-mass stars. While the spectra and first scientific results have already been published by Przygodda et al. (2003) and Kessler-Silacci et al. (2004) we perform a more detailed analysis of the 10um silicate feature. In our analysis we assume that this emission feature can be represented by a linear superposition of the wavelength-dependent opacity $\kappa_{\rm abs}(\lambda)$ describing the optical properties of silicate grains with different chemical composition, structure, and grain size. The determination of an adequate fitting equation is another goal of this study. Using a restricted number of fitting parameters we investigate which silicate species are necessary for the compositional fitting. Particles with radii of 0.1um- and 1.5um consisting of amorphous olivine and pyroxene, forsterite, enstatite, and quartz have been considered. Only compact, homogeneous dust grains have been used in the presented fitting procedures. In this context we show that acceptable fitting results can also be achieved if emission properties of porous silicate grains are considered instead. Although some previous studies give reasons for the similarity between the dust in circumstellar disks of TTauri stars and Herbig Ae/Be stars, a quantitative comparison has been missing, so far. Therefore, we conclude with a discussion of the results of a 10um spectroscopic survey of van Boekel et al. (2005) who focus on Herbig Ae/Be stars, the higher mass counterparts of T Tauri stars and draw comparisons to this and other studies. We find that the results of our study of T Tauri systems partly agree with previous studies of Herbig Ae/Be stars.Comment: 17 pages, 6 figure

Hand and Eye Dominance in Sport: Are Cricket Batters Taught to Bat Back-to-Front?

Background: When first learning to bimanually use a tool to hit a target (e.g., when chopping wood or hitting a golf ball), most people assume a stance that is dictated by their dominant hand. By convention, this means that a ‘right-handed’ or ‘left-handed’ stance that places the dominant hand closer to the striking end of the tool is adopted in many sports. Objective: The aim of this study was to investigate whether the conventional stance used for bimanual hitting provides the best chance of developing expertise in that task. Methods: Our study included 43 professional (international/first-class) and 93 inexperienced (<5 years’ experience) cricket batsmen. We determined their batting stance (plus hand and eye dominance) to compare the proportion of batters who adopted a reversed stance when batting (that is, the opposite stance to that expected based on their handedness). Results: We found that cricket batsmen who adopted a reversed stance had a stunning advantage, with professional batsmen 7.1 times more likely to adopt a reversed stance than inexperienced batsmen, independent of whether they batted right or left handed or the position of their dominant eye. Conclusion: Findings imply that batsmen who adopt a conventional stance may inadvertently be batting ‘back-to-front’ and have a significant disadvantage in the game. Moreover, the results may generalize more widely, bringing into question the way in which other bimanual sporting actions are taught and performed

Development and implementation of ISAR, a new synthesis platform for radiopharmaceutical production

Abstract Background PET radiopharmaceutical development and the implementation of a production method on a synthesis module is a complex and time-intensive task since new synthesis methods must be adapted to the confines of the synthesis platform in use. Commonly utilized single fluid bus architectures put multiple constraints on synthesis planning and execution, while conventional microfluidic solutions are limited by compatibility at the macro-to-micro interface. In this work we introduce the ISAR synthesis platform and custom-tailored fluid paths leveraging up to 70 individually addressable valves on a chip-based consumable. The ISAR synthesis platform replaces traditional stopcock valve manifolds with a fluidic chip that integrates all fluid paths (tubing) and valves into one consumable and enables channel routing without the single fluid bus constraint. ISAR can scale between the macro- (10 mL), meso- (0.5 mL) and micro- (≤0.05 mL) domain seamlessly, addressing the macro-to-micro interface challenge and enabling custom tailored fluid circuits for a given application. In this paper we demonstrate proof-of-concept by validating a single chip design to address the challenge of synthesizing multiple batches of [13N]NH3 for clinical use throughout the workday. Results ISAR was installed at an academic PET Center and used to manufacture [13N]NH3 in > 96% radiochemical yield. Up to 9 batches were manufactured with a single consumable chip having parallel paths without the need to open the hot-cell. Quality control testing confirmed the ISAR-based [13N]NH3 met existing clinical release specifications, and utility was demonstrated by imaging a rodent with [13N]NH3 produced on ISAR. Conclusions ISAR represents a new paradigm in radiopharmaceutical production. Through a new system architecture, ISAR integrates the principles of microfluidics with the standard volumes and consumables established in PET Centers all over the world. Proof-of-concept has been demonstrated through validation of a chip design for the synthesis of [13N]NH3 suitable for clinical use.https://deepblue.lib.umich.edu/bitstream/2027.42/152186/1/41181_2019_Article_77.pd

Phenotypic redshifts with self-organizing maps: A novel method to characterize redshift distributions of source galaxies for weak lensing

Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on coarse measurements of spectral energy distributions in a few filters to estimate the redshift distribution of source galaxies. In this regime, sample variance, shot noise, and selection effects limit the attainable accuracy of redshift calibration and thus of cosmological constraints. We present a new method to combine wide-field, few-filter measurements with catalogs from deep fields with additional filters and sufficiently low photometric noise to break degeneracies in photometric redshifts. The multi-band deep field is used as an intermediary between wide-field observations and accurate redshifts, greatly reducing sample variance, shot noise, and selection effects. Our implementation of the method uses self-organizing maps to group galaxies into phenotypes based on their observed fluxes, and is tested using a mock DES catalog created from N-body simulations. It yields a typical uncertainty on the mean redshift in each of five tomographic bins for an idealized simulation of the DES Year 3 weak-lensing tomographic analysis of $\sigma_{\Delta z} = 0.007$, which is a 60% improvement compared to the Year 1 analysis. Although the implementation of the method is tailored to DES, its formalism can be applied to other large photometric surveys with a similar observing strategy.Comment: 24 pages, 11 figures; matches version accepted to MNRA