55 research outputs found

    Low-temperature, high-resolution magnetic force microscopy using a quartz tuning fork

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    We have developed a low temperature, high resolution magnetic force microscope (MFM) using a quartz tuning fork that can operate in a magnetic field. A tuning fork with a spring constant of 1300 N/m mounted with a commercial MFM cantilever tip was used. We have obtained high resolution images of the stray magnetic fields exerted from grains with a spatial resolution of 15 nm and force resolution of 2 pN at 4.2 K. Tuning fork based magnetic force microscopes have the potential to be used at millikelvin temperatures due to their low power dissipation and high force sensitivity.Comment: 3page

    Magnetoresistance measurements of Graphene at the Charge Neutrality Point

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    We report on transport measurements of the insulating state that forms at the charge neutrality point of graphene in a magnetic field. Using both conventional two-terminal measurements, sensitive to bulk and edge conductance, and Corbino measurements, sensitive only to the bulk conductance, we observed a vanishing conductance with increasing magnetic fields. By examining the resistance changes of this insulating state with varying perpendicular and in-plane fields, we probe the spin-active components of the excitations in total fields of up to 45 Tesla. Our results indicate that \nu=0 quantum Hall state in single layer graphene is not spin polarized

    Repeatability of induced sputum measurements in moderate to severe asthma

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    SummaryBackgroundNovel therapies are being developed for patients with moderate to severe asthma. These patients may have neutrophilic airway inflammation. Induced sputum is commonly used as an endpoint in clinical trials of asthma therapies. We have performed repeated induced sputum sampling in moderate to severe asthma patients to understand the variability of cell counts, including neutrophils, and performed power calculations for studies in this group of patients.MethodsNineteen patients with moderate to severe asthma with evidence of airflow obstruction (FEV1 ā‰¤ 80% predicted) and suboptimal control (ACQ ā‰„ 1) performed repeated induced sputum separated by 1 month.ResultsThe Ri of neutrophil percentage and absolute eosinophil count demonstrated good (0.61) and moderate (0.56) repeatability respectively, but there was a poor level of agreement for eosinophil percentage and absolute neutrophil counts. The within subject SD for sputum neutrophil percentage was 15.8. In cross over studies, sample sizes of n = 14 and n = 54 are required to detect changes in neutrophil percentages by 20 and 10 % respectively at 90% power.ConclusionsSputum neutrophil percentage has good reproducibility in patients with moderate to severe asthma

    T lymphocyte insensitivity to corticosteroids in chronic obstructive pulmonary disease

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    <p>Abstract</p> <p>Background</p> <p>There are increased numbers of activated lymphocytes in the lungs of chronic obstructive pulmonary disease (COPD) patients. The clinical benefits of corticosteroids in COPD patients are limited. Our hypothesis is that lymphocytes play a role in this corticosteroid insensitivity.</p> <p>Objectives</p> <p>To investigate the effects of the corticosteroid dexamethasone on lung lymphocyte cytokine production from patients with COPD compared to controls.</p> <p>Methods</p> <p>Cultured airway lymphocytes obtained by bronchoscopy from healthy non-smokers (HNS), smokers (S) and COPD patients were stimulated with phytohaemagglutinin (PHA) & phorbol myristate acetate (PMA), +/- dexamethasone. Supernatants were assayed for interleukin (IL)-2 and interferon (IFN)Ī³. Immunofluoresence was used to analyse changes in CD8 glucocorticoid receptor (GRĪ± and GRĪ²) expression.</p> <p>Results</p> <p>The inhibition of PHA/PMA stimulated IFNĪ³ production by dexamethasone was reduced in COPD patients compared to HNS (<it>p </it>< 0.05 at concentrations from 0.1-1 Ī¼M). There was also a significant reduction (<it>p </it>< 0.05) in the mean inhibitory effect at 1 Ī¼M in COPD patients (54.1%) compared to smokers (72.1%), and in smokers compared to HNS (85.5%). There was a numerically reduced effect of dexamethasone on IL-2 production that did not reach statistical significance. There was no difference in GRĪ± and GRĪ² expression in follicular CD8 cells between COPD patients (50.9% and 30.4% respectively) and smokers (52.9% and 29.7% respectively).</p> <p>Conclusions</p> <p>IFNĪ³ production from COPD airway lymphocytes is corticosteroid insensitive. This phenomenon may be important in the poor clinical response often observed with corticosteroids.</p

    An investigation into E-business service in the UK telecommunication manufacturing industry

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    Nowadays, suppliersā€™ product and service quality has risen in importance with a manufacturerā€™s push to develop core competencies and capitalise on global operations and markets. However, due to the complex features of business service, suppliers are facing significant challenges in providing service effectively and developing business collaboration. This is further complicated by the development of information and communication technologies (ICTs). This paper thus attempts to investigate the factors influencing buyersā€™ e-service (EBS) requirements and the impact of these requirements on business collaboration. Based on a questionnaire survey with 500 UK telecommunication manufacturers, this research identifies buyersā€™ different EBS requirements for different types of suppliers and the impact of ICTs on EBS requirements. While for suppliers our findings provide insights into buyersā€™ EBS requirements, they can help buyers to develop appropriate supplier selection criteria. The findings also contribute to a better understanding of the development of buyer and supplier business collaboration

    Tunable fractional quantum Hall phases in bilayer graphene

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    Symmetry-breaking in a quantum system often leads to complex emergent behavior. In bilayer graphene (BLG), an electric field applied perpendicular to the basal plane breaks the inversion symmetry of the lattice, opening a band gap at the charge neutrality point. In a quantizing magnetic field, electron interactions can cause spontaneous symmetry-breaking within the spin and valley degrees of freedom, resulting in quantum Hall effect (QHE) states with complex order. Here, we report fractional QHE states in BLG that show phase transitions that can be tuned by a transverse electric field. This result provides a model platform with which to study the role of symmetry-breaking in emergent states with topological order

    Internet-delivered cognitive behavioural therapy programme to reduce depressive symptoms in patients with multiple sclerosis: a multicentre, randomised, controlled, phase 3 trial

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    BACKGROUND: Depression is three to four times more prevalent in patients with neurological and inflammatory disorders than in the general population. For example, in patients with multiple sclerosis, the 12-month prevalence of major depressive disorder is around 25% and it is associated with a lower quality of life, faster disease progression, and higher morbidity and mortality. Despite its clinical relevance, there are few treatment options for depression associated with multiple sclerosis and confirmatory trials are scarce. We aimed to evaluate the safety and efficacy of a multiple sclerosis-specific, internet-based cognitive behavioural therapy (iCBT) programme for the treatment of depressive symptoms associated with the disease. METHODS: This parallel-group, randomised, controlled, phase 3 trial of an iCBT programme to reduce depressive symptoms in patients with multiple sclerosis was carried out at five academic centres with large outpatient care units in Germany and the USA. Patients with a neurologist-confirmed diagnosis of multiple sclerosis and depressive symptoms were randomly assigned (1:1:1; automated assignment, concealed allocation, no stratification, no blocking) to receive treatment as usual plus one of two versions of the iCBT programme Amiria (stand-alone or therapist-guided) or to a control condition, in which participants received treatment as usual and were offered access to the iCBT programme after 6 months. Masking of participants to group assignment between active treatment and control was not possible, although raters were masked to group assignment. The predefined primary endpoint, which was analysed in the intention-to-treat population, was severity of depressive symptoms as measured by the Beck Depression Inventory-II (BDI-II) at week 12 after randomisation. This trial is registered at ClinicalTrials.gov, NCT02740361, and is complete. FINDINGS: Between May 3, 2017, and Nov 4, 2020, we screened 485 patients for eligibility. 279 participants were enrolled, of whom 101 were allocated to receive stand-alone iCBT, 85 to receive guided iCBT, and 93 to the control condition. The dropout rate at week 12 was 18% (50 participants). Both versions of the iCBT programme significantly reduced depressive symptoms compared with the control group (BDI-II between-group mean differences: control vs stand-alone iCBT 6Ā·32 points [95% CI 3Ā·37-9Ā·27], p<0Ā·0001, effect size d=0Ā·97 [95% CI 0Ā·64-1Ā·30]; control vs guided iCBT 5Ā·80 points [2Ā·71-8Ā·88], p<0Ā·0001, effect size d=0Ā·96 [0Ā·62-1Ā·30]). Clinically relevant worsening of depressive symptoms was observed in three participants in the control group, one in the stand-alone iCBT group, and none in the guided iCBT group. No occurrences of suicidality were observed during the trial and there were no deaths. INTERPRETATION: This trial provides evidence for the safety and efficacy of a multiple sclerosis-specific iCBT tool to reduce depressive symptoms in patients with the disease. This remote-access, scalable intervention increases the therapeutic options in this patient group and could help to overcome treatment barriers
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