Reconceiving International Education: Theorizing Limits and Possibilities for Transcultural Learning

This multi-voiced paper explores the micro-level dimensions of human learning and becoming from transcultural encounters, lessons and/or curriculum under heightened transnationalism. It posits that mainstream approaches to conceptualizing the ‘education’ of international education lack sufficient theorization of difference, sociality, history and learning in trans-local spaces and suggests that there are expanding networks of transcultural engagements to be examined under the umbrella of international education. To explore this reconceived pedagogical landscape of international education three specific cases are presented: an auto-ethnographic reflection on coming into and making sense of one’s international experience, a conceptual framing of internationalizing preservice education curriculum and a qualitative analysis of the pedagogical impacts of undergraduates’ international internships. Each case illustrates the complexities, possibilities and challenges of (framing) learning and becoming in sites of transcultural engagement

Minimising microbubble size through oscillation frequency control

Microbubbles are bubbles below 1 mm in size and have been extensively deployed in industrial settings to improve gaseous exchange between gas and liquid phases. The high surface to volume ratio offered by microbubbles enables them to enhance transport phenomena and therefore can be used to reduce energy demands in many applications including, waste water aeration, froth flotation, oil emulsion separations and evaporation dynamics. Microbubbles can be produced by passing a gas stream through a micro-porous diffuser placed at the gas–liquid interface. Previous work has shown that oscillating this gas steam can reduce the bubble size and therefore increase energy savings. In this work we show that it is possible to further reduce microbubble size (and consequently maximise the number of bubbles) by varying the frequency of the oscillating gas supply. Three different microbubble generation systems have been investigated; an acoustic oscillation system and a mesh membrane, a fluidic oscillator coupled to a single orifice membrane and a fluidic oscillator coupled to a commercially available ceramic diffuser. In all three bubble generation methods there is an optimum oscillation frequency at which the bubble size is minimised and the number of microbubbles maximised. In some cases a reduction in bubble size of up to 73% was achieved compared with non-optimal operating frequencies. The frequency at which this optimum occurs is dependent on the bubble generation system; more specifically the geometry of the system, the type micro-porous diffuser and the gas flow rate. This work proves that by tuning industrial microbubble generators to their optimal oscillation frequency will result in a reduction of microbubble size and increase their number density. This will further improve gaseous exchange rates and therefore improve the efficiency of the industrial processes where they are being employed to produce bubbles, leading to a reduction in associated energy costs and an increase in the overall economic and energetic feasibility of these processes

Engineering ligand-responsive RNA controllers in yeast through the assembly of RNase III tuning modules

The programming of cellular networks to achieve new biological functions depends on the development of genetic tools that link the presence of a molecular signal to gene-regulatory activity. Recently, a set of engineered RNA controllers was described that enabled predictable tuning of gene expression in the yeast Saccharomyces cerevisiae through directed cleavage of transcripts by an RNase III enzyme, Rnt1p. Here, we describe a strategy for building a new class of RNA sensing-actuation devices based on direct integration of RNA aptamers into a region of the Rnt1p hairpin that modulates Rnt1p cleavage rates. We demonstrate that ligand binding to the integrated aptamer domain is associated with a structural change sufficient to inhibit Rnt1p processing. Three tuning strategies based on the incorporation of different functional modules into the Rnt1p switch platform were demonstrated to optimize switch dynamics and ligand responsiveness. We further demonstrated that these tuning modules can be implemented combinatorially in a predictable manner to further improve the regulatory response properties of the switch. The modularity and tunability of the Rnt1p switch platform will allow for rapid optimization and tailoring of this gene control device, thus providing a useful tool for the design of complex genetic networks in yeast

Prevalence, predictive factors and clinical course of persistent pain associated with teeth displaying periapical healing following nonsurgical root canal treatment:a prospective study

AIMS: To investigate the prevalence, pain catastrophizing and other predictive factors and clinical course of persistent pain/discomfort associated with teeth displaying periapical healing following nonsurgical root canal treatment (NSRCT). // METHODOLOGY: One hundred and ninety‐eight patients (264 teeth) who had NSRCT were reviewed at 5–14 months, postoperatively. Teeth with persistent post‐treatment pain or discomfort, plus evidence of periapical healing were further monitored 0.5, 4 and 10 years later. Pain Catastrophizing Scale (PCS) and Short Form of the McGill Pain Questionnaire (SF‐MPQ) were completed. Predictive factors were investigated using logistic regression models. // RESULTS: Twenty‐four per cent (60/249) of teeth displaying periapical healing at first review were associated with persistent pain or discomfort. Fifty‐five teeth monitored 6–7 months later were associated with reduction in pain (17/30) or discomfort (7/25). Cone beam computed tomography (CBCT) of eight teeth with persistent symptoms and complete periapical healing (by conventional radiographs) revealed distinct, small apical radiolucencies (n = 3) or root apex fenestration through the buccal plate (n = 2). History of chronic pain (headache, temporo‐mandibular joint, masticatory muscle, neck, shoulder or back pain; P = 0.005), preoperative pain (P = 0.04), responsive pulp (P = 0.009), tooth crack (P = 0.05) and small periapical radiolucency (P = 0.005) were significant predictive factors. The PCS revealed 16 patients (22 teeth) were catastrophizers (PCS ≥ 30), but this had no influence on post‐treatment symptoms (P = 0.5). // CONCLUSIONS: Persistent pain or discomfort associated with teeth showing periapical healing at the first review after NSRCT, decreased in intensity in most cases over the following 6 months. Longer‐term follow‐up revealed spontaneous improvement or symptom resolution in the majority of those with confirmed radiographic the absence of periapical disease. Five predictive factors (history of chronic pain, teeth with responsive pulps, association with pain, diagnosis of tooth crack before treatment and diameter of preoperative radiolucency) were identified

The BAH domain of Rsc2 is a histone H3 binding domain

Bromo-adjacent homology (BAH) domains are commonly found in chromatin-associated proteins and fall into two classes; Remodels the Structure of Chromatin (RSC)-like or Sir3-like. Although Sir3-like BAH domains bind nucleosomes, the binding partners of RSC-like BAH domains are currently unknown. The Rsc2 subunit of the RSC chromatin remodeling complex contains an RSC-like BAH domain and, like the Sir3-like BAH domains, we find Rsc2 BAH also interacts with nucleosomes. However, unlike Sir3-like BAH domains, we find that Rsc2 BAH can bind to recombinant purified H3 in vitro, suggesting that the mechanism of nucleosome binding is not conserved. To gain insight into the Rsc2 BAH domain, we determined its crystal structure at 2.4 Å resolution. We find that it differs substantially from Sir3-like BAH domains and lacks the motifs in these domains known to be critical for making contacts with histones. We then go on to identify a novel motif in Rsc2 BAH that is critical for efficient H3 binding in vitro and show that mutation of this motif results in defective Rsc2 function in vivo. Moreover, we find this interaction is conserved across Rsc2-related proteins. These data uncover a binding target of the Rsc2 family of BAH domains and identify a novel motif that mediates this interaction

Cancellations in Neutrinoless Double Beta Decay and the Neutrino Mass Matrix

In a degenerate scheme with mass m_0 a complete analysis of the allowed range of the effective electron neutrino Majorana mass is performed. Special attention is paid to effects of cancellations caused either by intrinsic CP parities of the eigenstates (CP invariance) or by complex mixing matrix elements (CP violation). We investigate all possibilities and give in each case constraints on the phases, the relative CP parities or the neutrino mass scale. A solar mixing angle \sin^2 2 \theta smaller than 0.7 jeopardizes the degenerate mass scheme. A key value of /m_0 is identified, which is independent on the solar solution and would rule out certain schemes. Also it would answer the question regarding the presence of CP violation. Even if a total neutrino mass scale and an effective mass is measured, the value of the phases or parities is not fixed, unless in some special cases. The resulting uncertainty in the other mass matrix elements is at least of the same order than the one stemming from nuclear matrix elements calculations.Comment: 20 pages, 10 figures. Title, abstract and parts of the text change

Structural plasticity of the living kinetochore

The kinetochore is a large, evolutionarily conserved protein structure that connects chromosomes with microtubules. During chromosome segregation, outer kinetochore components track depolymerizing ends of microtubules to facilitate the separation of chromosomes into two cells. In budding yeast, each chromosome has a point centromere upon which a single kinetochore is built, which attaches to a single microtubule. This defined architecture facilitates quantitative examination of kinetochores during the cell cycle. Using three independent measures-calibrated imaging, FRAP, and photoconversion-we find that the Dam1 submodule is unchanged during anaphase, whereas MIND and Ndc80 submodules add copies to form an "anaphase configuration" kinetochore. Microtubule depolymerization and kinesin-related motors contribute to copy addition. Mathematical simulations indicate that the addition of microtubule attachments could facilitate tracking during rapid microtubule depolymerization. We speculate that the minimal kinetochore configuration, which exists from G1 through metaphase, allows for correction of misattachments. Our study provides insight into dynamics and plasticity of the kinetochore structure during chromosome segregation in living cells

The role of GαO-mediated signaling in the rostral ventrolateral medulla oblongata in cardiovascular reflexes and control of cardiac ventricular excitability.

The heart is controlled by the sympathetic and parasympathetic limbs of the autonomic nervous system with inhibitory signaling mechanisms recruited in both limbs. The aim of this study was to determine the role of inhibitory heterotrimeric G proteins in the central nervous mechanisms underlying autonomic control of the heart and its potential role in arrhythmogenesis. Mice with conditional deletion of the inhibitory heterotrimeric G protein GαO in the presympathetic area of the rostral ventral lateral medulla (RVLM) were generated to determine the role of GαO-mediated signalling in autonomic control and electrophysiological properties of the heart. GαO deletion within the RVLM was not associated with changes in heart rate (HR) or the arterial blood pressure at rest (home cage, normal behavior). However, exposure to stressful conditions (novel environment, hypoxia, or hypercapnia) in these mice was associated with abnormal HR responses and an increased baroreflex gain when assessed under urethane anesthesia. This was associated with shortening of the ventricular effective refractory period. This phenotype was reversed by systemic beta-adrenoceptor blockade, suggesting that GαO depletion in the RVLM increases central sympathetic drive. The data obtained support the hypothesis that GαO-mediated signaling within the presympathetic circuits of the RVLM contributes to the autonomic control of the heart. GαO deficiency in the RVLM has a significant impact on cardiovascular responses to stress, cardiovascular reflexes and electrical properties of the heart.This research was supported by the Medical Research Council (MRC Clinical Research Training Fellowship to RA), British Heart Foundation (Ref: RG/14/4/30736), Wellcome Trust (Wellcome Trust Senior Research Fellowship to AVG; Ref: 095064), and by the Intramural Research Program of the National Institutes of Health, National Institute of Environmental Health Sciences (Project Z01- ES-101643 to LB). This work was facilitated by the National Institute for Health Research Barts Cardiovascular Biomedical Research Unit

The host metabolite D-serine contributes to bacterial niche specificity through gene selection

Escherichia coli comprise a diverse array of both commensals and niche-specific pathotypes. The ability to cause disease results from both carriage of specific virulence factors and regulatory control of these via environmental stimuli. Moreover, host metabolites further refine the response of bacteria to their environment and can dramatically affect the outcome of the host–pathogen interaction. Here, we demonstrate that the host metabolite, D-serine, selectively affects gene expression in E. coli O157:H7. Transcriptomic profiling showed exposure to D-serine results in activation of the SOS response and suppresses expression of the Type 3 Secretion System (T3SS) used to attach to host cells. We also show that concurrent carriage of both the D-serine tolerance locus (dsdCXA) and the locus of enterocyte effacement pathogenicity island encoding a T3SS is extremely rare, a genotype that we attribute to an ‘evolutionary incompatibility’ between the two loci. This study demonstrates the importance of co-operation between both core and pathogenic genetic elements in defining niche specificity