Studies on the foliar epidermal tissues of three species of Digitaria Haller in Jos, Plateau state Nigeria

Foliar epidermal studies were carried out on Digitaria iburua Stapf, Digitaria exilis Stapf and Digitaria barbinodis Henr. with the aim of determining the patterns of variation in their epidermal characteristics and assessing the value of leaf epidermal characters in the identification of these culturally important species. Micro hairs, silica bodies, short cells, anticlinal wall pattern, epidermal cell shape and stomata index were diagonistic characters. While micro hairs were distributed on the surfaces of Digitaria exilis and Digitaria barbinodi, they were absent in Digitaria iburua. Short cells were present on the surfaces of Digitaria iburua and Digitaria barbinodis but absent on Digitaria exilis. Stomata index was smallest in Digitaria barbinodis distinguishing it from the other two species. The epidermal cell shape varied from rectangular to polygonal while the anticlinal wall pattern varied from straight to wavy in the three species. Other useful characters for distinguishing the species are epidermal cell size, stomata size and stomata number.Keywords: Digitaria iburua, microhairs, foliar, silica bodies, Digitaria exili

High-density information storage in an absolutely defined aperiodic sequence of monodisperse copolyester

Synthesis of a polymer composed of a large discrete number of chemically distinct monomers in an absolutely defined aperiodic sequence remains a challenge in polymer chemistry. The synthesis has largely been limited to oligomers having a limited number of repeating units due to the difficulties associated with the step-by-step addition of individual monomers to achieve high molecular weights. Here we report the copolymers of ??-hydroxy acids, poly(phenyllactic-co-lactic acid) (PcL) built via the cross-convergent method from four dyads of monomers as constituent units. Our proposed method allows scalable synthesis of sequence-defined PcL in a minimal number of coupling steps from reagents in stoichiometric amounts. Digital information can be stored in an aperiodic sequence of PcL, which can be fully retrieved as binary code by mass spectrometry sequencing. The information storage density (bit/Da) of PcL is 50% higher than DNA, and the storage capacity of PcL can also be increased by adjusting the molecular weight (~38???kDa)

Eosinophils Are Important for Protection, Immunoregulation and Pathology during Infection with Nematode Microfilariae

Eosinophil responses typify both allergic and parasitic helminth disease. In helminthic disease, the role of eosinophils can be both protective in immune responses and destructive in pathological responses. To investigate whether eosinophils are involved in both protection and pathology during filarial nematode infection, we explored the role of eosinophils and their granule proteins, eosinophil peroxidase (EPO) and major basic protein-1 (MBP-1), during infection with Brugia malayi microfilariae. Using eosinophil-deficient mice (PHIL), we further clarify the role of eosinophils in clearance of microfilariae during primary, but not challenge infection in vivo. Deletion of EPO or MBP-1 alone was insufficient to abrogate parasite clearance suggesting that either these molecules are redundant or eosinophils act indirectly in parasite clearance via augmentation of other protective responses. Absence of eosinophils increased mast cell recruitment, but not other cell types, into the broncho-alveolar lavage fluid during challenge infection. In addition absence of eosinophils or EPO alone, augmented parasite-induced IgE responses, as measured by ELISA, demonstrating that eosinophils are involved in regulation of IgE. Whole body plethysmography indicated that nematode-induced changes in airway physiology were reduced in challenge infection in the absence of eosinophils and also during primary infection in the absence of EPO alone. However lack of eosinophils or MBP-1 actually increased goblet cell mucus production. We did not find any major differences in cytokine responses in the absence of eosinophils, EPO or MBP-1. These results reveal that eosinophils actively participate in regulation of IgE and goblet cell mucus production via granule secretion during nematode-induced pathology and highlight their importance both as effector cells, as damage-inducing cells and as supervisory cells that shape both innate and adaptive immunity

The extent of metalloproteinase-mediated LAG3 cleavage limits the efficacy of PD1 blockade

Inhibitory receptors control immune responses preventing exacerbated T cell activation and the onset of autoimmunity; however, they also limit antitumor immunity. Enhanced co-expression of PD1 and LAG3 phenotypically mark functionally exhausted tumor-specific T cells, with dual PD1/LAG3 blockade synergistically limiting tumor growth in murine models. Like PD1, LAG3 expression is induced on activated T cells to negatively regulate T cell activation and proliferation and LAG3 is also required for maximal regulatory T (Treg) cell function. However, LAG3 expression and function is itself regulated by cell surface cleavage of the transmembrane domain connecting peptide by ADAM10 and ADAM17 metalloproteinase-disintegrins. This releases soluble LAG3, of which no biological function has been found to date. To investigate the impact of LAG3 cleavage on T cells within tumors, a non-cleavable LAG3 mouse (LAG3.NC) was generated in which exons 7 and 8 of Lag3, including the connecting peptide, is deleted in Cre-expressing cells. These exons are replaced and modified so that the connecting peptide is absent preventing LAG3 cleavage. LAG3.NC CD4Cre mice (with non-cleavable LAG3 expressed on all CD8+ and CD4+ T cells, including Tregs) and LAG3.NC E8ICre mice (restricted to CD8+ T cells only) exhibit enhanced expression of LAG3 on the respective T cell subsets in B16-F10 or MC38 tumors, co-expressing with PD1. Despite increased LAG3 expression, no difference in B16-F10 or MC38 tumor growth was observed in either LAG3.NC CD4Cre or LAG3.NC E8ICre mice compared with wild-type littermates. Upon therapeutic administration of anti-PD1 antibody (clone G4), MC38 tumor-bearing wild-type mice show significant tumor regression and 40% become tumor-free resulting in long-term survival. LAG3.NC CD4Cre mice were resistant to anti-PD1 therapy and succumb to tumor growth. However, anti-PD1 mediated tumor regression and long-term survival in LAG3.NC E8ICre mice. Analysis of re-stimulated CD8+ TILs isolated from LAG3.NC CD4Cre mice did not show enhanced IFN-gamma and TNF-alpha production following anti-PD1 therapy, which was observed with LAG3.NC E8ICre mice or wild-type littermates. Moreover, reduced proliferation was observed for all T cell subsets in LAG3.NC CD4Cre mice compared with LAG3.NC E8ICre and wild-type littermates following anti-PD1 treatment. As LAG3.NC CD4Cre, but not LAG3.NC E8ICre mice, are resistant to the favorable antitumor immune effects induced by anti-PD1, this suggests that enhanced LAG3 expression on CD4+ T cells or Tregs may act as a barrier to effective anti-PD1 immunotherapy. LAG3.NC mice crossed with Cre that restricts non-cleavable LAG3 to Tregs (Foxp3yfpiCre) or CD4+ T cells (ThPOKCre) are currently under analysis

Supersymmetric QCD: Exact Results and Strong Coupling

We revisit two longstanding puzzles in supersymmetric gauge theories. The first concerns the question of the holomorphy of the coupling, and related to this the possible definition of an exact (NSVZ) beta function. The second concerns instantons in pure gluodynamics, which appear to give sensible, exact results for certain correlation functions, which nonetheless differ from those obtained using systematic weak coupling expansions. For the first question, we extend an earlier proposal of Arkani-Hamed and Murayama, showing that if their regulated action is written suitably, the holomorphy of the couplings is manifest, and it is easy to determine the renormalization scheme for which the NSVZ formula holds. This scheme, however, is seen to be one of an infinite class of schemes, each leading to an exact beta function; the NSVZ scheme, while simple, is not selected by any compelling physical consideration. For the second question, we explain why the instanton computation in the pure supersymmetric gauge theory is not reliable, even at short distances. The semiclassical expansion about the instanton is purely formal; if infrared divergences appear, they spoil arguments based on holomorphy. We demonstrate that infrared divergences do not occur in the perturbation expansion about the instanton, but explain that there is no reason to think this captures all contributions from the sector with unit topological charge. That one expects additional contributions is illustrated by dilute gas corrections. These are infrared divergent, and so difficult to define, but if non-zero give order one, holomorphic, corrections to the leading result. Exploiting an earlier analysis of Davies et al, we demonstrate that in the theory compactified on a circle of radius beta, due to infrared effects, finite contributions indeed arise which are not visible in the formal limit that beta goes to infinity.Comment: 28 pages, two references added, one typo correcte

Neural correlates of enhanced visual short-term memory for angry faces: An fMRI study

Copyright: © 2008 Jackson et al.Background: Fluid and effective social communication requires that both face identity and emotional expression information are encoded and maintained in visual short-term memory (VSTM) to enable a coherent, ongoing picture of the world and its players. This appears to be of particular evolutionary importance when confronted with potentially threatening displays of emotion - previous research has shown better VSTM for angry versus happy or neutral face identities.Methodology/Principal Findings: Using functional magnetic resonance imaging, here we investigated the neural correlates of this angry face benefit in VSTM. Participants were shown between one and four to-be-remembered angry, happy, or neutral faces, and after a short retention delay they stated whether a single probe face had been present or not in the previous display. All faces in any one display expressed the same emotion, and the task required memory for face identity. We find enhanced VSTM for angry face identities and describe the right hemisphere brain network underpinning this effect, which involves the globus pallidus, superior temporal sulcus, and frontal lobe. Increased activity in the globus pallidus was significantly correlated with the angry benefit in VSTM. Areas modulated by emotion were distinct from those modulated by memory load.Conclusions/Significance: Our results provide evidence for a key role of the basal ganglia as an interface between emotion and cognition, supported by a frontal, temporal, and occipital network.The authors were supported by a Wellcome Trust grant (grant number 077185/Z/05/Z) and by BBSRC (UK) grant BBS/B/16178

The Lived Experience of People with Mental Health and Substance Misuse Problems: Dimensions of Belonging

Introduction: People with co-occurring mental health and substance misuse problems are among the most excluded in society. A need to feel connected to others has been articulated in the occupational science literature although the concept of belonging itself has not been extensively explored within this paradigm. This paper reports findings from research that explored the meaning and experience of belonging for four people living with dual diagnosis in the United Kingdom. Method: Researchers employed an interpretative phenomenological approach to the study. Four semi-structured interviews were carried out. The interviews were guided by questions around the meaning of belonging, barriers to belonging and how belonging and not belonging impacted on participants’ lives. Data analysis facilitated the identification of themes across individual accounts and enabled comparisons. Findings: Data analysis identified four themes – belonging in family, belonging in place, embodied understandings of belonging and barriers to belonging. Conclusion: The findings add further insights into the mutable nature of belonging. A link between sense of belonging and attachment theory has been proposed, along with a way to understand the changeable and dependent nature of belonging through ‘dimensions of belonging’

Freeze-In Production of FIMP Dark Matter

We propose an alternate, calculable mechanism of dark matter genesis, "thermal freeze-in," involving a Feebly Interacting Massive Particle (FIMP) interacting so feebly with the thermal bath that it never attains thermal equilibrium. As with the conventional "thermal freeze-out" production mechanism, the relic abundance reflects a combination of initial thermal distributions together with particle masses and couplings that can be measured in the laboratory or astrophysically. The freeze-in yield is IR dominated by low temperatures near the FIMP mass and is independent of unknown UV physics, such as the reheat temperature after inflation. Moduli and modulinos of string theory compactifications that receive mass from weak-scale supersymmetry breaking provide implementations of the freeze-in mechanism, as do models that employ Dirac neutrino masses or GUT-scale-suppressed interactions. Experimental signals of freeze-in and FIMPs can be spectacular, including the production of new metastable coloured or charged particles at the LHC as well as the alteration of big bang nucleosynthesis.Comment: 30 pages, 7 figures, PDFLaTex. References adde

The Phyre2 web portal for protein modeling, prediction and analysis

Phyre2 is a suite of tools available on the web to predict and analyze protein structure, function and mutations. The focus of Phyre2 is to provide biologists with a simple and intuitive interface to state-of-the-art protein bioinformatics tools. Phyre2 replaces Phyre, the original version of the server for which we previously published a paper in Nature Protocols. In this updated protocol, we describe Phyre2, which uses advanced remote homology detection methods to build 3D models, predict ligand binding sites and analyze the effect of amino acid variants (e.g., nonsynonymous SNPs (nsSNPs)) for a user's protein sequence. Users are guided through results by a simple interface at a level of detail they determine. This protocol will guide users from submitting a protein sequence to interpreting the secondary and tertiary structure of their models, their domain composition and model quality. A range of additional available tools is described to find a protein structure in a genome, to submit large number of sequences at once and to automatically run weekly searches for proteins that are difficult to model. The server is available at http://www.sbg.bio.ic.ac.uk/phyre2. A typical structure prediction will be returned between 30 min and 2 h after submission