Tunable few-electron double quantum dots and Klein tunnelling in ultra-clean carbon nanotubes

Quantum dots defined in carbon nanotubes are a platform for both basic scientific studies and research into new device applications. In particular, they have unique properties that make them attractive for studying the coherent properties of single electron spins. To perform such experiments it is necessary to confine a single electron in a quantum dot with highly tunable barriers, but disorder has until now prevented tunable nanotube-based quantum-dot devices from reaching the single-electron regime. Here, we use local gate voltages applied to an ultra-clean suspended nanotube to confine a single electron in both a single quantum dot and, for the first time, in a tunable double quantum dot. This tunability is limited by a novel type of tunnelling that is analogous to that in the Klein paradox of relativistic quantum mechanics.Comment: 21 pages including supplementary informatio

Future developments in brain-machine interface research

Neuroprosthetic devices based on brain-machine interface technology hold promise for the restoration of body mobility in patients suffering from devastating motor deficits caused by brain injury, neurologic diseases and limb loss. During the last decade, considerable progress has been achieved in this multidisciplinary research, mainly in the brain-machine interface that enacts upper-limb functionality. However, a considerable number of problems need to be resolved before fully functional limb neuroprostheses can be built. To move towards developing neuroprosthetic devices for humans, brain-machine interface research has to address a number of issues related to improving the quality of neuronal recordings, achieving stable, long-term performance, and extending the brain-machine interface approach to a broad range of motor and sensory functions. Here, we review the future steps that are part of the strategic plan of the Duke University Center for Neuroengineering, and its partners, the Brazilian National Institute of Brain-Machine Interfaces and the École Polytechnique Fédérale de Lausanne (EPFL) Center for Neuroprosthetics, to bring this new technology to clinical fruition

The transition of reported pain in different body regions – a one-year follow-up study

BACKGROUND: The course of pain at a specific region such as the lower back has previously been shown as well as for generalized pain. However we have not found any report on the course of pain from various different specific regions. The aim of this investigation was to study the one-year transition of reported pain in different body locations. METHODS: From a general population 14555 men and women, 46–68 years, responded to an extensive health questionnaire including the standardized Nordic questionnaire. The population represented 27% of the total population within the age group in Malmö, Sweden. At the one year follow-up 12607 responded to the questionnaire, yielding a response rate of 87%. The one year prevalence of long-lasting pain and the pattern of pain reporting from different regions were studied for men and women. RESULTS: The one-year prevalence of long-lasting neck pain was 14% (95% CI 13–15) among men and 25% (95% CI 24–26) among women at baseline and 15% (95% CI 14–16) for the men and 23% (95% CI 22–24) for the women at follow-up. Of those reporting neck pain "all the time" at baseline, 48% of the men and 54% of the women also reported neck pain "all the time" at the one-year follow-up. At the follow-up neck pain was reported as present "often" by 43% of the men and 47% of the women who reported neck pain "often" at baseline. Similar transition pattern were found for neck, shoulders, elbow/wrist/hand and lower back symptoms, as well as consistent prevalence rates. CONCLUSION: The one-year transition pattern of reported pain was similar in different body regions and among men and women. Furthermore the prevalence rates of long-lasting pain in the population were consistent at baseline and the follow-up. The findings of similar transition patterns support the interpretation of long-lasting pain as a generalized phenomenon rather than attributed to specific exposure. This may have implications for future pain research

Older People, Sense of Coherence and Community

Population ageing is a global trend and even though years added to life often are lived in good health; it will have an impact on healthcare, housing and facilities, and social security costs. Healthy ageing in place, especially in one’s own home and community, increasingly receives attention from health professionals, researchers, and policymakers. In this chapter, we first discuss the meaning of the concept of healthy ageing, and how Sense of Coherence contributes to this process. Next, we discuss the characteristics of the community in which older people live their lives and how the community can provide resources (GRR and SRR) to strengthen Sense of Coherence and hence perceived well-being and quality of life

Peroxiredoxin 3 Is a Redox-Dependent Target of Thiostrepton in Malignant Mesothelioma Cells

Thiostrepton (TS) is a thiazole antibiotic that inhibits expression of FOXM1, an oncogenic transcription factor required for cell cycle progression and resistance to oncogene-induced oxidative stress. The mechanism of action of TS is unclear and strategies that enhance TS activity will improve its therapeutic potential. Analysis of human tumor specimens showed FOXM1 is broadly expressed in malignant mesothelioma (MM), an intractable tumor associated with asbestos exposure. The mechanism of action of TS was investigated in a cell culture model of human MM. As for other tumor cell types, TS inhibited expression of FOXM1 in MM cells in a dose-dependent manner. Suppression of FOXM1 expression and coincidental activation of ERK1/2 by TS were abrogated by pre-incubation of cells with the antioxidant N-acetyl-L-cysteine (NAC), indicating its mechanism of action in MM cells is redox-dependent. Examination of the mitochondrial thioredoxin reductase 2 (TR2)-thioredoxin 2 (TRX2)-peroxiredoxin 3 (PRX3) antioxidant network revealed that TS modifies the electrophoretic mobility of PRX3. Incubation of recombinant human PRX3 with TS in vitro also resulted in PRX3 with altered electrophoretic mobility. The cellular and recombinant species of modified PRX3 were resistant to dithiothreitol and SDS and suppressed by NAC, indicating that TS covalently adducts cysteine residues in PRX3. Reduction of endogenous mitochondrial TRX2 levels by the cationic triphenylmethane gentian violet (GV) promoted modification of PRX3 by TS and significantly enhanced its cytotoxic activity. Our results indicate TS covalently adducts PRX3, thereby disabling a major mitochondrial antioxidant network that counters chronic mitochondrial oxidative stress. Redox-active compounds like GV that modify the TR2/TRX2 network may significantly enhance the efficacy of TS, thereby providing a combinatorial approach for exploiting redox-dependent perturbations in mitochondrial function as a therapeutic approach in mesothelioma

The Integrin Receptor in Biologically Relevant Bilayers: Insights from Molecular Dynamics Simulations

Integrins are heterodimeric (αβ) cell surface receptors that are potential therapeutic targets for a number of diseases. Despite the existence of structural data for all parts of integrins, the structure of the complete integrin receptor is still not available. We have used available structural data to construct a model of the complete integrin receptor in complex with talin F2–F3 domain. It has been shown that the interactions of integrins with their lipid environment are crucial for their function but details of the integrin/lipid interactions remain elusive. In this study an integrin/talin complex was inserted in biologically relevant bilayers that resemble the cell plasma membrane containing zwitterionic and charged phospholipids, cholesterol and sphingolipids to study the dynamics of the integrin receptor and its effect on bilayer structure and dynamics. The results of this study demonstrate the dynamic nature of the integrin receptor and suggest that the presence of the integrin receptor alters the lipid organization between the two leaflets of the bilayer. In particular, our results suggest elevated density of cholesterol and of phosphatidylserine lipids around the integrin/talin complex and a slowing down of lipids in an annulus of ~30 Å around the protein due to interactions between the lipids and the integrin/talin F2–F3 complex. This may in part regulate the interactions of integrins with other related proteins or integrin clustering thus facilitating signal transduction across cell membranes

Epidermólisis ampollosa, reporte de un caso

Introduction: epidermolysis bullosa refers to a heterogeneous group of chronic hereditary pimple-like diseases affecting the skin and mucosae with blisters and vesicles after minimal injury, with variable involvement of other organs.Case report: 3-year-old female patient with exulcerated skin lesions and some erythema crust-plaques, with scaling at exposure sites such as hands, knees, feet, back of the neck and genitals. She was admitted to “Hermanos Cordové” Pediatric Teaching Hospital in Manzanillo. The medical care was based on maintaining the integrity of the skin avoiding trauma, temperature control, nutrition and prevention of secondary infections. A simple epidermolysis bullosa is diagnosed by skin biopsy.Conclusions: the disease is scarcely known with low incidence and prevalence. It is a major problem in the family and social environment, as parents are dealing with a rare disease of genetic origin and poor prognosis. Medical-social support helps to minimize the problems by means of information and coordination. Treatment requires the care of a multidisciplinary and specialized team.Introducción: la epidermólisis bulosa se refiere a un grupo heterogéneo de enfermedades hereditarias ampulosas crónicas, que afectan a la piel y las mucosas con formación de ampollas y vesículas tras mínimos traumatismos, con afectación variable de otros órganos.Presentación de caso: paciente femenina de 3 años de edad con lesiones de piel exulceradas y algunas eritematocostrosas en placas, con descamación en sitios de exposición como manos, rodillas, pies, parte posterior del cuello y genitales. Se encontraba ingresada en el Hospital Pediátrico Docente “Hermanos Cordové", de Manzanillo. Los cuidados médicos se basaron en mantener la entereza de la piel evitando traumatismo, control de la temperatura, nutrición y prevención de infecciones secundarias. Se diagnostica por biopsia de piel una epidermólisis bulosa simple. Conclusiones: la enfermedad es poco conocida con baja incidencia y prevalencia. Supone un problema de gran magnitud en el entorno familiar y social, al enfrentarse los padres a una enfermedad rara con origen genético y de mal pronóstico. El apoyo médico-social ayuda a minimizar los problemas, a través de la información y coordinación. Para su tratamiento es necesaria la atención de un equipo multidisciplinario y especializado.