Design of a scanning tunneling microscope for electrochemical applications

A design for a scanning tunneling microscope that is well suited for electrochemical investigations is presented. The construction of the microscope ensures that only the tunneling tip and the sample participate in electrochemical reactions. The design also allows rapid replacement of the tip or sample, and enables facile introduction of auxiliary electrodes for use in electrochemical experiments. The microscope utilizes stepper motor driven approach mechanics in order to achieve fully remote operation and to allow reproducible coarse control of tip/sample spacings for electrochemical experiments. Highly ordered pyrolytic graphite images at atomic resolution in air and aqueous solutions can be obtained with this microscope

Produtividade de plantações de eucalipto intercaladas com espécies nativas em áreas de pastagens degradadas no noroeste do Estado do Paraná.

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Effect of density of state on isotope effect exponent of two-band superconductors

The exact formula of Tc's equation and the isotope effect exponent of two-band s-wave superconductors in weak-coupling limit are derived by considering the influence of two kinds of density of state : constant and van Hove singularity. The pairing interaction in each band consisted of 2 parts : the electron-phonon interaction and non-electron-phonon interaction are included in our model. We find that the interband interaction of electron-phonon show more effect on isotope exponent than the intraband interaction and the isotope effect exponent with constant density of state can fit to an experimental data,MgB2, and high-Tc superconductors, better than van Hove singularity density of state.Comment: 11 pages. accepted in Physica

Fermiology and superconductivity studies on the non-tetrachalcogenafulvalene structured organic superconductor beta-(BDA-TTP)_2SbF_6

The quantum oscillatory effect and superconductivity in a non-tetrachalcogenafulvalene (TCF) structure based organic superconductor beta-(BDA-TTP)_2SbF_6 are studied. Here the Shubnikov-de Haas effect (SdH) and angular dependent magnetoresistance oscillations (AMRO) are observed. The oscillation frequency associated with a cylindrical Fermi surface is found to be about 4050 tesla, which is also verified by the tunnel diode oscillator (TDO) measurement. The upper critical field Hc2 measurement in a tilted magnetic field and the TDO measurement in the mixed state reveal a highly anisotropic superconducting nature in this material. We compared physical properties of beta-(BDA-TTP)_2SbF_6 with typical TCF structure based quasi two-dimensional organic conductors. A notable feature of beta-(BDA-TTP)_2SbF_6 superconductor is a large value of effective cyclotron mass m_c^*=12.4+/1.1 m_e, which is the largest yet found in an organic superconductor. A possible origin of the enhanced effective mass and its relation to the superconductivity are briefly discussed.Comment: 8 pages, 10 figure

Non-human TRIM5 variants enhance recognition of HIV-1-infected cells by CD8+ T cells

Tripartite motif-containing protein 5 (TRIM5) restricts human immunodeficiency virus type-1 (HIV-1) in a species-specific manner by uncoating viral particles while activating early innate responses. Although the contribution of TRIM5 proteins to cellular immunity has not yet been studied, their interactions with the incoming viral capsid and the cellular proteasome led us to hypothesize a role for them. Here, we investigate whether the expression of two non-human TRIM5 orthologs, rhesus TRIM5α (RhT5) and TRIM-cyclophilin A (TCyp), both of which are potent restrictors of HIV-1, could enhance immune recognition of infected cells by CD8+ T cells. We illustrate how TRIM5 restriction improves CD8+ T cell-mediated HIV-1 inhibition. Moreover, when TRIM5 activity was blocked by the non-immunosuppressive analog of cyclosporin A, SmBz-CsA, we found a significant reduction in CD107a/MIP1β expression in HIV-1-specific CD8+ T cells. This finding underscores the direct link between TRIM5 restriction and activation of CD8+ T-cell responses. Interestingly, cells expressing RhT5 induced stronger CD8+ T-cell responses through the specific recognition of the HIV-1 capsid by the immune system. The underlying mechanism of this process may involve TRIM5-specific capsid recruitment to cellular proteasomes and increase peptide availability for loading and presentation of HLA class I antigens. In summary, we identified a novel function for non-human TRIM5 variants in cellular immunity. We hypothesise that TRIM5 can couple innate viral sensing and CD8+ T-cell activation to increase species barriers against retrovirus infection. IMPORTANCE: New therapeutics to tackle HIV-1 infection should aim to combine rapid innate viral sensing and cellular immune recognition. Such strategies could prevent seeding of the viral reservoir and the immune damage that occurs during acute infection. The non-human TRIM5 variants, rhesus TRIM5α (RhT5) and TRIM-cyclophilin A (TCyp), are attractive candidates owing to their potency in sensing HIV-1 and blocking its activity. Here, we show that expression of RhT5 and TCyp in HIV-1-infected cells improves CD8+ T cell-mediated inhibition through the direct activation of HIV-1-specific CD8+ T-cell responses. We found that the potency in CD8+ activation was stronger for RhT5 variants and capsid-specific CD8+ T-cells in a mechanism that relies on TRIM5-dependent particle recruitment to cellular proteasomes. This novel mechanism couples innate viral sensing with cellular immunity in a single protein and could be exploited to develop innovative therapeutics for control of HIV-1 infection

The Discovery of Neptune Revisited

The study of the differences detected between the observed and the predicted positions of Uranus taking only the ancient planets into account led to the discovery of planet Neptune in 1846. This event remains one of the best accomplishments ever achieved in the history of Astronomy and Classical Mechanics. In this paper, we study the perturbations in the orbit of Uranus due to Neptune and its effects from a modern numerical point of view of the $N$-body problem. The effects induced by Pluto in the orbit of Neptune, as the historical search for a ninth planet in the Solar System (recently boostered again with the hypothesis of the so-called Planet Nine) back in the days was propelled by some supposed small inconsistencies in the orbit of the ice giants, are also analyzed.Comment: Article is being prepared for submission to Astronomy & Astrophysic

How to summarise and report written qualitative data from patients: a method for use in cancer support care

Goals of work: Determination of key themes to aid the analysis of qualitative data collected at three cancer support centres in England, using the Measure Yourself Concerns and Wellbeing (MYCaW) questionnaire. Patients and methods: People with cancer who use complementary therapies experience and value a wide range of treatment effects, yet tools are urgently required to quantitatively measure these outcomes. MYCAW is an individualised questionnaire used in cancer support centres providing complementary therapies, scoring 'concerns or problems' and 'wellbeing' and collects qualitative data about other major events in a patient's life and what has been most important to the patient. Content analysis on 782 MYCaW questionnaires from people at these cancer support centres was carried out. The "concerns", "other things going on in their life" and "important aspects of centre" were thematically categorised, externally validated by a focus group and the inter-rater reliability calculated. Main results: Clinical information from a cancer patient's perspective was collected that is not measured on standard quality of life questionnaires; furthermore some themes acknowledge the multifaceted aspects of CAM provision, rather than information only relating to the therapeutic intervention. Categories for qualitative MYCaW analysis have been established providing a tool for future research and/or service delivery improvement within cancer support centres such as these. Conclusions: The established themes provide a framework to aid analysis of qualitative aspects of complementary therapy care for people with cancer, improving our understanding of how the patient’s cancer experience can be aided by complementary therapies in specialized cancer centres

Acute Bout of Exercise May Preserve Peripheral Blood Mononuclear Cell Viability Under Oxidative Stress

Nasal breathing (NB) during exercise induces hypercapnic conditions, which may improve exercise performance. However, the impact of NB on cell viability (CV) remains unexplored. PURPOSE: This study investigated the effects of a single bout of exercise with NB on CV following lipopolysaccharide (LPS)-induced oxidative stress in peripheral blood mononuclear cells (PBMCs). METHODS: Twelve men (age=22.5±3.03 years) were randomly assigned to either the NB group (N=6) or the combined breathing (oral + nasal breathing, CB, N=6) group. Each group performed a graded maximal exercise test (GXT) on a recumbent bike. Plasma samples were collected before and immediately after the GXT to isolate PBMCs, followed by culturing for 12 hours, either with LPS (1µg/mL) or without LPS stimulation. RESULTS: There were no significant differences in CV between the NB and CB groups. CV did not differ between pre-exercise (92.78±1.52%) and immediately post-exercise (93.33±1.76%). However, after 12 hours of culture without LPS, CV was significantly lower in the immediately post-exercise condition (90.60±1.87%) than in the pre-exercise condition (93.45±1.49%, p=0.01). When stimulated with LPS and cultured for 12 hours, CV between the pre-exercise (90.16±2.04%) and immediately post-exercise conditions (91.70±1.50%) was not significantly different. However, both pre-exercise and immediately post-exercise CVs with LPS stimulation were significantly lower (p=0.029) than the pre-exercise CVs without LPS stimulation. CONCLUSION: Decreased CV following maximal exercise may be associated with exercise-induced physiological and biochemical stressors, such as reactive oxygen species, pro-inflammatory cytokines, and metabolic byproducts. Although CV decreased under oxidative stress conditions, a single bout of exercise showed a tendency to preserve viability, which may be attributed to exercise-induced reduction in susceptibility to LPS-induced viability loss by enhancing anti-inflammatory pathways and antioxidant defenses