Luminescence dosimetry with ceramic materials for application to radiological emergencies and other incidents.

The likelihood of the occurrence of radiological accidents which can induce significant health consequences to the members of the public has raised the importance of developing a personal radiation dosimetry system applicable to populations not monitored by dedicated dosemeters. Mobile phones are personal devices with high ubiquity and great potential for accident dosimetry applications. Alumina surface mount resistors (SMRs) are abundant in the printed circuit board of mobile phones and their potential as fortuitous dosemeters has been investigated using thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques. The physical mechanism of the generation of luminescence of the alumina SMRs is, however, less known. The basic luminescence defects in SMRs were identified to be F-type centres and their emission process was shown to be temperature dependent and highly quenched at room temperature (RT). The trap environment of beta irradiated SMRs includes a series of closely spaced traps covering thermal depths between 0.9-1.4 eV; predicting an average lifetime for thermal fading at RT of ca 23 years. Trapped charges evicted by thermal or optical stimulation are likely to recombine at F-type centres and contribute to the luminescence response that is likely to be thermally assisted via the vibrational modes of the lattice. A phonon-assisted de-excitation of the trapped charge population could additionally be involved in the mechanism of athermal or anomalous fading. Based on the temperature dependence of the rate of fading, a model is presented for the anomalous fading observed where phonon-assisted and tunnelling effects alternate or operate simultaneously depending on the temperature of the material. A number of aspects related to the use of SMRs in dosimetry seem to benefit from the investigation of the physical processes, although for accurate dose reconstruction it is imperative to know the energy of the ionising radiation source and the position of the mobile phone relative to the direction of the source. For example, at low-energy exposures the dose may be over-estimated, not only due to the non-flat energy response of the alumina, but also due to the presence of several parts of the mobile phone which can increase the amount of energy deposited in alumina substrates due to backscatter effects. In addition, MCNP simulations indicated that for low-energy exposures, such as for 192Ir, differences of up to an order-of-magnitude between resistor and whole body dose are expected. Finally, to specify the most appropriate dose conversion coefficients that can be applied to estimate whole body dose from OSL / TL determinations, the knowledge of the exposure geometry is crucial

An electrophoretic study of fetal mouse brain proteins after in vivo exposure to phenytoin and disulfiram

Although there have been two-dimensional electrophoretic studies on fetal brain tissue (for instance, Yoshida and Takahashi, 1980), the emphasis in most of this work has been on developmental changes in protein expression, and not on the effects that drugs have on fetal brain protein complement. Klose and co-workers (1977) did an early study using two-dimensional gel electrophoresis to determine the effects of various teratogens on whole embryos. No protein changes were found and that line of research was not continued. In this study two-dimensional gel electrophoresis is extensively used, in the belief that the usefulness of this technique to experimental teratology has not been fully evaluated. It is reasonable to suppose that a central nervous system teratogen administered during critical periods of susceptibility will led to perturbations of orderly brain development, and that these perturbations will be reflected as changes to the protein complement. The total brain protein complement of mice that have been exposed to drugs in utero will therefore be analysed, in the hope that any inductions or deletions of proteins as a result of drug exposure may provide a clue to the molecular events underlying drug injury to the fetus

UVR8 mediated spatial differences as a prerequisite for UV-B induced inflorescence phototropism

In Arabidopsis hypocotyls, phototropins are the dominant photoreceptors for the positive phototropism response towards unilateral ultraviolet-B (UV-B) radiation. We report a stark contrast of response mechanism with inflorescence stems with a central role for UV RESISTANCE LOCUS 8 (UVR8). The perception of UV-B occurs mainly in the epidermis and cortex with a lesser contribution of the endodermis. Unilateral UV-B exposure does not lead to a spatial difference in UVR8 protein levels but does cause differential UVR8 signal throughout the stem with at the irradiated side 1) increase of the transcription factor ELONGATED HYPOCOTYL 5 (HY5), 2) an associated strong activation of flavonoid biosynthesis genes and flavonoid accumulation, 3) increased GA2oxidase expression, diminished gibberellin1 levels and accumulation of DELLA protein REPRESSOR OF GA1 (RGA) and, 4) increased expression of the auxin transport regulator, PINOID, contributing to local diminished auxin signalling. Our molecular findings are in support of the Blaauw theory (1919), suggesting that differential growth occurs trough unilateral photomorphogenic growth inhibition. Together the data indicate phototropin independent inflorescence phototropism through multiple locally UVR8-regulated hormone pathways

Cells in Space

Discussions and presentations addressed three aspects of cell research in space: the suitability of the cell as a subject in microgravity experiments, the requirements for generic flight hardware to support cell research, and the potential for collaboration between academia, industry, and government to develop these studies in space. Synopses are given for the presentations and follow-on discussions at the conference and papers are presented from which the presentations were based. An Executive Summary outlines the recommendations and conclusions generated at the conference

Facial attractiveness among rhesus macaques (Macaca mulatta) : manipulating and measuring preferences for conspecifics' facial characteristics

The face holds a central role in both human and nonhuman primate social interactions, through the communication of feelings and intentions via facial expressions and by acting as a means of recognising individuals. Humans, however, also employ their faces in mate attraction and assessment, an area that has received little attention in nonhuman primates. Many researchers have proposed that human aesthetic judgments of facial attractiveness have a biological basis, and these preferences have evolved via sexual selection processes during human evolution. The use of the face in attractiveness assessments need not be limited to humans. Rather, there is good reason to suggest that this may also apply to other nonhuman primates, based on homologies in the way in which primates use their faces, and on evidence that the face is a site of sexual selection for many primate species. It was the aim of this thesis to explore whether facial traits may also play a role in judgements of attractiveness in a nonhuman primate, the rhesus macaque( Macaca mulatta), in an effort to understand whether humans are unique in utilising the face as a mechanism of mate assessment. Three factors that are reported to influence facial attractiveness in humans are facial symmetry, sexual dimorphism, and averageness. To assess whether they also play a role in nonhuman primates, a series of experiments were conducted where digital images of adult male and female rhesus macaque faces were altered for these features. Opposite-sexed images were then displayed to adult males and females in a captive setting. Eye gaze measures were utilised to assess visual preference for, and the relative importance of, these traits. These experiments yielded mixed results. Increasing facial symmetry of opposite-sexed conspecifics positively influenced the dependent gaze measures employed here. Manipulating degree of facial sexual dimorphism had little influence on the visual gaze of either sex. Facial averageness positively influenced visual preferences for opposite-sexed conspecifics among both sexes, although increasing degree of averageness did not. The last topic to be explored was facial colouration. Rhesus macaques like, various other species of anthropoid primates, possess facial displays of red secondary sexual colouration. As above, animals viewed digitally altered pale and red versions of opposite-sexed conspecifics. Although females displayed preferences for red male faces, males displayed no clear preferences based on female facial colour. This raises the possibility that male and female facial colour may serve different roles in intraspecific signaling. While it cannot be concluded that visual preferences are indeed indicative of real-life preferences, the results do indicate that animals are not indifferent to variations in conspecific facial features. The present findings have important implications regarding the evolution of facial attractiveness, as they provide the first experimental evidence suggesting that facial features may serve as a mechanism for mate selection across primate taxa and that both human and nonhuman primates may employ similar criteria to appraise facial attractiveness

Establishing the developmental function of the rhamnogalacturonan II component of pectin

The primary plant cell wall consists of a complex set of polysaccharides including pectin, cellulose and hemicelluloses that are critical for normal plant development. There are three major forms of pectin, rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HGA). Of these, the pectic polysaccharide RG-II, is the least abundant but the most complex. Despite this, RG-II is highly conserved among vascular plants, suggesting animportant function which is dependent upon structure. RG-II consists of four structurally welldefined side chains attached to a backbone of 1,4-linked galacturonic acid (GalA) residues and exists predominately as a dimer in plant cell walls. RG-II function has yet to be identified; however, mutations affecting RG-II structure have severe growth and development defects. 3-deoxy-D-manno-2-octulosonic acid (Kdo) is a rarely found sugar and is a component of the RGII side chain C. Kdo biosynthesis has been well characterised and a number of Kdo synthesis genes identified in Arabidopsis. Traditional gene knockout approaches to study the effect of disrupting Kdo biosynthesis have been limited by the apparent lethality of these mutants. Alternative approaches using partial knockout, inducible gene silencing and chemical approaches have being employed with the primary aim of specifically altering the structure of RG-II to determine the developmental function of RG-II. By combination of a GAL4/VP16 expression system and ALCR/alcA ethanol-switch to achieve temporal and spatial control of transgene expression, it has been possible to generate a genetic tool kit consisting of a series of Arabidopsis lines in which it should be possible to disrupt Kdo biosynthesis in specific tissues at strictly defined developmental stages. As a proof of concept the J0951/iKdsB line, in which expression of an AtKdsB antisense sequence is restricted to the epidermis and root cap in the presence of ethanol, is shown to be almost completely devoid of root hairs when grown under induced conditions. This result is suggestive of a role for RG-II in tip growth processes and is consistent with the phenotypes of null mutants in which a failure in pollen tube elongation results in gametophyte lethality. In silico and in vitro approaches are used to investigate the potential application of an inhibitor of AtKdsB, 2?-deoxy Kdo, as a tool for the disruption of CMP-Kdo synthesis in plants. Using homology modelling the Arabidopsis and E. coli enzymes are shown to have a near identical active site conformation. Using recombinantly expressed AtKdsB in enzyme kinetic and inhibition studies the substrate analogue 2?-deoxy-Kdo was shown to be a potent in vitro inhibitor of AtKdsB with a Ki of 1.26 ± 0.15 ??, consistent with measures of the Kd made by isothermal titration calorimetry (ITC) analysis. The 2?-deoxy-Kdo was subsequently applied in vivo and results in a severe inhibition of cell elongation of Arabidopsis root cells that can be partially rescued by either Kdo or boron. It is likely that 2?-deoxy-Kdo application disrupts CMP-Kdo biosynthesis with consequences for RG-II structure and dimer formation

A systematic review

This study was conducted at the Psychology Research Centre ( PSI/01662 ), School of Psychology , the University of Minho , supported by the Foundation for Science and Technology (FCT) through the Portuguese State Budget ( UID/PSI/01662/2020 ). This research was also supported by FCT projects PTDC/MHC/PCN/1530/2014. We thank the anonymous reviewers for their insightful comments and recommendations, which has assisted us in improving the quality and presentation of this article. Publisher Copyright: © 2023 The AuthorsThe caregiver's touch behavior during early infancy is linked to multiple developmental outcomes. However, social touch remains a challenging construct to operationalize, and although observational tools have been a gold standard for measuring touch in caregiver-infant interactions, no systematic review has been conducted before. We followed the PRISMA guidelines and reviewed the literature to describe and classify the main characteristics of the available observational instruments. Of the 3042 publications found, we selected 45 that included an observational measure, and from those we identified 12 instruments. Most of the studies were of infants younger than six months of age and assessed touch in two laboratory tasks: face-to-face interaction and still-face procedure. We identified three approaches for evaluating the caregiver's touch behavior: strictly behavioral (the observable touch behavior), functional (the functional role of the touch behavior), or mixed (a combination of the previous two). Half of the instruments were classified as functional, 25% as strictly observational, and 25% as mixed. The lack of conceptual and operational uniformity and consistency between instruments is discussed.publishersversionpublishe

Women in Science 2017

Ever since its 1967 start, SURF has been a cornerstone of Smith’s science education. Women in Science 2017 summarizes research done by Smith College’s SURF Program participants during the summer of 2017. 151 students participated in SURF (144 hosted on campus and nearby eld sites), supervised by 58 faculty mentor-advisors drawn from the Clark Science Center and connected to its eighteen science, mathematics, and engineering departments and programs and associated centers and units. At summer’s end, SURF participants summarized their research experiences for this publication.https://scholarworks.smith.edu/clark_womeninscience/1006/thumbnail.jp

Characterisation of a gain-of-function mutant of CYSTEINE-RICH RECEPTOR-LIKE KINASE 10 (CRK10) in Arabidopsis thaliana

Receptor-like kinases (RLKs) comprise a large superfamily of proteins in plant genomes, and play essential roles in plant growth, development and response to biotic and abiotic stresses. The CYSTEINE-RICH RECEPTOR-LIKE KINASES (CRKs) comprise one of the largest subfamilies of RLKs with over 40 members in Arabidopsis thaliana, and although a few members of the family have been initially characterised, their precise biological functions remain largely unknown. This thesis reports the characterisation of a novel gain-of-function allele of CYSTEINE-RICH RECEPTOR-LIKE KINASE 10 (CRK10) in A. thaliana which was isolated from a chemical mutagenesis screen. This mutation causes the substitution of alanine 397 with a threonine residue in subdomain III / αC-helix of the kinase domain of CRK10, and this novel allele has been accordingly registered as crk10-A397T with the Arabidopsis community database. The crk10- A397T mutant is a dwarf, and anatomical characterisation unveiled severely collapsed xylem vessels in the root and hypocotyl of the plant. Reporter lines suggested CRK10 is expressed in close association to vascular tissues, and a translational fusion with the fluorescent protein mCherry indicates that CRK10 is a plasma membrane-bound protein. Analysis of the recombinant WT and crk10- A397T versions of the cytoplasmic kinase domain of CRK10 demonstrated their auto-phosphorylation activity, and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis concluded that Thr397 acts as an additional auto-phosphorylation site in situ. Furthermore, an RNA-seq experiment revealed the constitutive induction of defence-related genes in the transcriptome of crk10- A397T mutant hypocotyls, including genes involved in the signalling pathways of the stress hormones salicylic acid (SA) and abscisic acid (ABA). Analysis of the composition of cell walls in the crk10-A397T mutant hypocotyls revealed extensive differences compared to the WT, an indication of cell wall remodelling mechanisms that are likely associated with the collapse of xylem vessels in this organ. Bioassays with the soil-borne vascular pathogen Fusarium oxysporum revealed that crk10-A397T mutant has a greater probability of survival to infection compared to WT plants. Analysis of genetic crosses demonstrated that key components of SA signalling pathways are required for the disease resistance phenotype of the crk10-A397T mutant