The structure of tris(chloromethyl)amine in the gas phase using quantum chemical calculations and gas electron diffraction and as a solid and melt using Raman spectroscopy

The equilibrium structure of tris(chloromethyl)amine, N(CH2Cl)3, has been determined in the gas phase using electron diffraction. Single-step distance corrections (representing the differences between the interatomic distances from the equilibrium structure and those from the vibrationally averaged structure) and amplitudes of vibration have been computed using semi-empirical molecular dynamics (SE-MD) simulations in order to treat accurately the description of the low-frequency, large-amplitude vibrational modes associated particularly with one CH2Cl group. A series of complementary theoretical calculations using the SOGGA11-X DFT functional with correlation-consistent basis sets of double-, triple-, and quadruple-ζ quality is also presented. The agreement between the experimental and theoretical equilibrium structural parameters attests to the accuracy of the applied theoretical calculations and of our gas-phase structural solution. Raman spectra have been recorded over a range of temperatures, allowing the solid and the melt to be studied, and the Raman-active intramolecular modes to be identified. Free from the influence of intermolecular interaction, the structure of tris(chloromethyl)amine in the gas phase is markedly different to that reported in the literature for the single crystal. This is discussed, and evidence for the anomeric effect in tris(chloromethyl)amine is evaluated

Season of conception in rural gambia affects DNA methylation at putative human metastable epialleles.

Throughout most of the mammalian genome, genetically regulated developmental programming establishes diverse yet predictable epigenetic states across differentiated cells and tissues. At metastable epialleles (MEs), conversely, epigenotype is established stochastically in the early embryo then maintained in differentiated lineages, resulting in dramatic and systemic interindividual variation in epigenetic regulation. In the mouse, maternal nutrition affects this process, with permanent phenotypic consequences for the offspring. MEs have not previously been identified in humans. Here, using an innovative 2-tissue parallel epigenomic screen, we identified putative MEs in the human genome. In autopsy samples, we showed that DNA methylation at these loci is highly correlated across tissues representing all 3 embryonic germ layer lineages. Monozygotic twin pairs exhibited substantial discordance in DNA methylation at these loci, suggesting that their epigenetic state is established stochastically. We then tested for persistent epigenetic effects of periconceptional nutrition in rural Gambians, who experience dramatic seasonal fluctuations in nutritional status. DNA methylation at MEs was elevated in individuals conceived during the nutritionally challenged rainy season, providing the first evidence of a permanent, systemic effect of periconceptional environment on human epigenotype. At MEs, epigenetic regulation in internal organs and tissues varies among individuals and can be deduced from peripheral blood DNA. MEs should therefore facilitate an improved understanding of the role of interindividual epigenetic variation in human disease

Using in vivo nickel to direct the pyrolysis of hyperaccumulator plant biomass : In vivo nickel to direct the pyrolysis of hyperaccumulator plant biomass

The effects of naturally occurring nickel in hyperaccumulator plants used for phytoremediation of contaminated soils on the microwave (MW) biomass pyrolysis are described for the first time. The presence of natural nickel appears to protect the hemicellulose component of the plant leading to 3 times lower yields of bio-gas and increased quantities of bio-char. The composition of the bio-oil is also affected

A Sustained Dietary Change Increases Epigenetic Variation in Isogenic Mice

Epigenetic changes can be induced by adverse environmental exposures, such as nutritional imbalance, but little is known about the nature or extent of these changes. Here we have explored the epigenomic effects of a sustained nutritional change, excess dietary methyl donors, by assessing genomic CpG methylation patterns in isogenic mice exposed for one or six generations. We find stochastic variation in methylation levels at many loci; exposure to methyl donors increases the magnitude of this variation and the number of variable loci. Several gene ontology categories are significantly overrepresented in genes proximal to these methylation-variable loci, suggesting that certain pathways are susceptible to environmental influence on their epigenetic states. Long-term exposure to the diet (six generations) results in a larger number of loci exhibiting epigenetic variability, suggesting that some of the induced changes are heritable. This finding presents the possibility that epigenetic variation within populations can be induced by environmental change, providing a vehicle for disease predisposition and possibly a substrate for natural selection

Insight into two-dimensional MoS2 by Raman and DFT study

Two-dimensional nanostructures have attracted attention for their unique physical properties and electronic structure and their enhanced catalytic activity. For MoS2 nanoribbons the most active catalytic sites are located at the edges of the two-dimensional nanosheets, while in graphene, functionalisation at the edges allows functionalisation with minimal perturbation of the sp2 graphene lattice. Vibrational spectroscopy, and Raman spectroscopy in particular is recognised as a valuable technique for characterising two-dimensional nanostructures. In this work we use IR and Raman spectroscopy to characterise the edges of these nanostructures. The low proportion of edge atoms requires increased sensitivity and selectivity and we demonstrate how plasmon resonance provides the necessary enhancement for graphene nanoribbons.Published versio

DeltaPCA: A Statistically Robust Method for Detecting Protein Analyte Binding to Aptamer-Functionalised Nanoparticles using Surface-Enhanced Raman Spectroscopy

In this work, we introduce a novel joint experimental design and computational analysis procedure to reliably and reproducibly quantify protein analyte binding to DNA aptamer-functionalised silver nanoparticles using slippery surface-enhanced Raman spectroscopy. We employ an indirect detection approach, based upon monitoring spectral changes in the covalent bond-stretching region as intermolecular bonds are formed between the surface-immobilized probe biomolecule and its target analyte. Sample variability is minimized by preparing aptamer-only and aptamer-plus-analyte samples under the same conditions, and then analysing difference spectra. To account for technical variability, multiple spectra are recorded from the same sample. Our new DeltaPCA analysis procedure takes into account technical variability within each spectral data set while also extracting statistically robust difference spectra between data sets. Proof of principle experiments using thiolated aptamers to detect CoV-SARS-2 spike protein reveal that analyte binding is mediated through the formation of N-H...X and C-H...X hydrogen bonds between the aptamer (H-bond donor) and protein (H-bond acceptor). Our computational analysis code can be freely downloaded from https://github.com/dlc62/DeltaPCA

Validating the use of a carbon dioxide laser for assessing nociceptive thresholds in adult domestic cats (Felis catus).

Thermal sensitivity in cats has historically been assessed using complex devices which require direct application to the patient and can therefore, in themselves, affect the measurement. This study aimed to validate the use of a remote low power (165 mW) carbon dioxide laser device for the assessment of thermal nociceptive thresholds in cats. Repeatabilites were established based on individual responses to three thermal tests on the same day and across 4 consecutive days. A total of 12 thermal tests were conducted on each of eight male and eight female de-sexed adult cats. As a control a non-thermal helium aiming laser was used to ensure the animals were responding to the thermal component of the device. All thermal tests elicited a behavioural response with the large majority being a skin twitch known as the panniculus reflex (97%). None of the non-thermal tests resulted in this reflex behaviour. There was no evidence that cats became sensitised or habituated to the low power thermal stimulus on any given day (P = 0.426) or across days (P = 0.115), or that there was any interaction between the two time factors (P = 0.084). There was also no difference in latency to respond between males and females (P = 0.094), although there was a significant interaction between the day of testing and the sex of the subject (P = 0.042). Significant intra-class correlations demonstrated that individual responses were repeatable over days 1–3 (all P < 0.05) but not over day 4 (P = 0.096). A significant intra-class correlation was also evident across all days when data were combined (P < 0.0001). This technique shows some promise in assessing individual nociceptive thresholds and as a tool to establish associated individual differences. It could, with more exploration, also provide an alternative thermal mechanism for testing the efficacy of analgesics in cats. The significant repeatabilities were low ranging from 0.241 to 0.414, this suggests that a number of extraneous factors may have influenced responses to CO2 laser stimulation at low power levels (165 mW). Further exploration of this technique on a larger sample than used here may allow elucidation of any other factors, including age or sex effects, that impact upon thermal sensitivity in the domestic cat