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Optimised Multi-channel Transcranial Direct Current Stimulation (MtDCS) reveals differential involvement of the right-ventrolateral prefrontal cortex (rVLPFC) and insular complex in those predisposed to aberrant experiences
Get PDFResearch has shown a prominent role for cortical hyperexcitability underlying aberrant perceptions, hallucinations, and distortions in human conscious experience – even in neurotypical groups. The rVLPFC has been identified as an important structure in mediating cognitive affective states / feeling conscious states. The current study examined the involvement of the rVLPFC in mediating cognitive affective states in those predisposed to aberrant experiences in the neurotypical population. Participants completed two trait-based measures: (i) the Cortical Hyperexcitability Index_II (CHi_II, a proxy measure of cortical hyperexcitability) and (ii) two factors from the Cambridge Depersonalisation Scale (CDS). An optimised 7-channel MtDCS montage for stimulation conditions (Anodal, Cathodal and Sham) was created targeting the rVLPFC in a single-blind study. At the end of each stimulation session, participants completed a body-threat task (BTAB) while skin conductance responses (SCRs) and psychological responses were recorded. Participants with signs of increasing cortical hyperexcitability showed significant suppression of SCRs in the Cathodal stimulation relative to the Anodal and sSham conditions. Those high on the trait-based measures of depersonalisation-like experiences failed to show reliable effects. Collectively, the findings suggest that baseline brain states can mediate the effects of neurostimulation which would be missed via sample level averaging and without appropriate measures for stratifying individual differences
The role of electronic bandstructure shape in improving the thermoelectric power factor of complex materials
No full textThe large variety of complex electronic structure materials and their alloys offer highly promising directions for improvements in thermoelectric (TE) power factors (PFs). Their electronic structure contains rich features, referred to as “surface complexity”, such as highly anisotropic, warped energy surface shapes with elongated features and threads in some cases. In this work, we use Boltzmann transport simulations to quantify the influence that the shape of the electronic structure energy surfaces has on the PF. Using analytical ellipsoidal bands, as well as realistic bands from a group of half-Heuslers, we show that band shape complexity alone can offer an advantage to the PF by ∼3× in realistic cases. However, the presence of anisotropic scattering mechanisms, such as ionized impurity or polar optical phonon scattering, can reduce these improvements by up to ∼50%. We show that expressions based on the simple ratio of the density of states effective mass to the conductivity effective mass, mDOS/mC, together with the number of valleys, can capture the anisotropy shape with a moderate to high degree of correlation. For this, we use a convenient way to extract these masses by mapping the complex bandstructures of materials to parabolic electronic structures, which can be done without the need for Boltzmann transport codes. Despite the fact that the PF depends on many parameters, information about the benefits of the band shape alone, may be very useful for identifying and understanding the performance of novel thermoelectric materials
Meditation for the primary and secondary prevention of cardiovascular disease
No full textBackground
Interventions incorporating meditation to address stress, anxiety, and depression, and improve self‐management, are becoming popular for many health conditions. Stress is a risk factor for cardiovascular disease (CVD) and clusters with other modifiable behavioural risk factors, such as smoking. Meditation may therefore be a useful CVD prevention strategy.
Objectives
To determine the effectiveness of meditation, primarily mindfulness‐based interventions (MBIs) and transcendental meditation (TM), for the primary and secondary prevention of CVD.
Search methods
We searched CENTRAL, MEDLINE, Embase, three other databases, and two trials registers on 14 November 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies.
Selection criteria
We included randomised controlled trials (RCTs) of 12 weeks or more in adults at high risk of CVD and those with established CVD. We explored four comparisons: MBIs versus active comparators (alternative interventions); MBIs versus non‐active comparators (no intervention, wait list, usual care); TM versus active comparators; TM versus non‐active comparators.
Data collection and analysis
We used standard Cochrane methods. Our primary outcomes were CVD clinical events (e.g. cardiovascular mortality), blood pressure, measures of psychological distress and well‐being, and adverse events. Secondary outcomes included other CVD risk factors (e.g. blood lipid levels), quality of life, and coping abilities. We used GRADE to assess the certainty of evidence.
Main results
We included 81 RCTs (6971 participants), with most studies at unclear risk of bias.
MBIs versus active comparators (29 RCTs, 2883 participants)
Systolic (SBP) and diastolic (DBP) blood pressure were reported in six trials (388 participants) where heterogeneity was considerable (SBP: MD ‐6.08 mmHg, 95% CI ‐12.79 to 0.63, I2 = 88%; DBP: MD ‐5.18 mmHg, 95% CI ‐10.65 to 0.29, I2 = 91%; both outcomes based on low‐certainty evidence). There was little or no effect of MBIs on anxiety (SMD ‐0.06 units, 95% CI ‐0.25 to 0.13; I2 = 0%; 9 trials, 438 participants; moderate‐certainty evidence), or depression (SMD 0.08 units, 95% CI ‐0.08 to 0.24; I2 = 0%; 11 trials, 595 participants; moderate‐certainty evidence). Perceived stress was reduced with MBIs (SMD ‐0.24 units, 95% CI ‐0.45 to ‐0.03; I2 = 0%; P = 0.03; 6 trials, 357 participants; moderate‐certainty evidence). There was little to no effect on well‐being (SMD ‐0.18 units, 95% CI ‐0.67 to 0.32; 1 trial, 63 participants; low‐certainty evidence). There was little to no effect on smoking cessation (RR 1.45, 95% CI 0.78 to 2.68; I2 = 79%; 6 trials, 1087 participants; low‐certainty evidence). None of the trials reported CVD clinical events or adverse events.
MBIs versus non‐active comparators (38 RCTs, 2905 participants)
Clinical events were reported in one trial (110 participants), providing very low‐certainty evidence (RR 0.94, 95% CI 0.37 to 2.42). SBP and DBP were reduced in nine trials (379 participants) but heterogeneity was substantial (SBP: MD ‐6.62 mmHg, 95% CI ‐13.15 to ‐0.1, I2 = 87%; DBP: MD ‐3.35 mmHg, 95% CI ‐5.86 to ‐0.85, I2 = 61%; both outcomes based on low‐certainty evidence). There was low‐certainty evidence of reductions in anxiety (SMD ‐0.78 units, 95% CI ‐1.09 to ‐0.41; I2 = 61%; 9 trials, 533 participants; low‐certainty evidence), depression (SMD ‐0.66 units, 95% CI ‐0.91 to ‐0.41; I2 = 67%; 15 trials, 912 participants; low‐certainty evidence) and perceived stress (SMD ‐0.59 units, 95% CI ‐0.89 to ‐0.29; I2 = 70%; 11 trials, 708 participants; low‐certainty evidence) but heterogeneity was substantial. Well‐being increased (SMD 0.5 units, 95% CI 0.09 to 0.91; I2 = 47%; 2 trials, 198 participants; moderate‐certainty evidence). There was little to no effect on smoking cessation (RR 1.36, 95% CI 0.86 to 2.13; I2 = 0%; 2 trials, 453 participants; low‐certainty evidence). One small study (18 participants) reported two adverse events in the MBI group, which were not regarded as serious by the study investigators (RR 5.0, 95% CI 0.27 to 91.52; low‐certainty evidence).
No subgroup effects were seen for SBP, DBP, anxiety, depression, or perceived stress by primary and secondary prevention.
TM versus active comparators (8 RCTs, 830 participants)
Clinical events were reported in one trial (201 participants) based on low‐certainty evidence (RR 0.91, 95% CI 0.56 to 1.49). SBP was reduced (MD ‐2.33 mmHg, 95% CI ‐3.99 to ‐0.68; I2 = 2%; 8 trials, 774 participants; moderate‐certainty evidence), with an uncertain effect on DBP (MD ‐1.15 mmHg, 95% CI ‐2.85 to 0.55; I2 = 53%; low‐certainty evidence). There was little or no effect on anxiety (SMD 0.06 units, 95% CI ‐0.22 to 0.33; I2 = 0%; 3 trials, 200 participants; low‐certainty evidence), depression (SMD ‐0.12 units, 95% CI ‐0.31 to 0.07; I2 = 0%; 5 trials, 421 participants; moderate‐certainty evidence), or perceived stress (SMD 0.04 units, 95% CI ‐0.49 to 0.57; I2 = 70%; 3 trials, 194 participants; very low‐certainty evidence). None of the trials reported adverse events or smoking rates.
No subgroup effects were seen for SBP or DBP by primary and secondary prevention.
TM versus non‐active comparators (2 RCTs, 186 participants)
Two trials (139 participants) reported blood pressure, where reductions were seen in SBP (MD ‐6.34 mmHg, 95% CI ‐9.86 to ‐2.81; I2 = 0%; low‐certainty evidence) and DBP (MD ‐5.13 mmHg, 95% CI ‐9.07 to ‐1.19; I2 = 18%; very low‐certainty evidence). One trial (112 participants) reported anxiety and depression and found reductions in both (anxiety SMD ‐0.71 units, 95% CI ‐1.09 to ‐0.32; depression SMD ‐0.48 units, 95% CI ‐0.86 to ‐0.11; low‐certainty evidence). None of the trials reported CVD clinical events, adverse events, or smoking rates.
Authors' conclusions
Despite the large number of studies included in the review, heterogeneity was substantial for many of the outcomes, which reduced the certainty of our findings. We attempted to address this by presenting four main comparisons of MBIs or TM versus active or inactive comparators, and by subgroup analyses according to primary or secondary prevention, where there were sufficient studies. The majority of studies were small and there was unclear risk of bias for most domains. Overall, we found very little information on the effects of meditation on CVD clinical endpoints, and limited information on blood pressure and psychological outcomes, for people at risk of or with established CVD.
This is a very active area of research as shown by the large number of ongoing studies, with some having been completed at the time of writing this review. The status of all ongoing studies will be formally assessed and incorporated in further updates
Comparative assessment of the performance of friction materials based on different agricultural wastes
Get PDFThe composition of friction materials is being revolutionised to exclude contentious components. This work comparatively used palm kernel shells, maize husks, cocoa bean shells and melon shells separately with seven other component materials to achieve novel friction materials. Friction and wear of the friction materials were measured using the test rig designed and constructed in-house for this research. Results showed that the maize husk-based friction material performed greatest in terms of thermal stability, wear, porosity and water absorption. Their thermal stability level indicates suitability for use in low-speed passenger cars and other allied braking applications. Using the selected agricultural residues in place of the contentious components in traditional friction materials would potentially solve health and environmental safety challenges
Atypia detected during breast screening and subsequent development of cancer : observational analysis of the Sloane atypia prospective cohort in England
No full textIntroduction The National Health Service (NHS) Breast Screening Programme aims to detect cancer earlier when treatment is more effective but can harm women by over diagnosing and overtreating cancers which would never have become symptomatic. As well as breast cancer, a spectrum of atypical epithelial proliferations (atypia) can also be detected as part of screening. This spectrum of changes, while not cancer, may mean that a woman is more likely to develop breast cancer in the future. Follow-up of atypia is not evidence based. We currently do not know which atypia should be detected to avoid future cancer. This study will explore how atypia develops into breast cancer in terms of number of women, time of cancer development, cancer type and severity, and whether this varies for different types of atypia.
Methods and analysis The Sloane cohort study began in April 2003 with ongoing data collection including atypia diagnosed through screening at screening units in the UK. The database for England has 3645 cases (24 September 2020) of epithelial atypia, with follow-up from 1 to 15 years. The outcomes include subsequent invasive breast cancer and the nature of subsequent cancer. Descriptive statistics will be produced. The observed rates of breast cancer at 1, 3 and 6 years for types of atypia will be reported with CIs, to enable comparison to women in the general population. Time to event methods will be used to describe the time to breast cancer diagnosis for the types of atypia, including flexible parametric modelling if appropriate. Patient representatives from Independent Cancer Patients’ Voice are included at every stage of the research.
Ethics and dissemination The study has received research ethics approval from the University of Warwick Biomedical and Scientific Research Ethics Committee (BSREC 10/20–21, 8 October 2020), Public Health England office for data release approvals (ODR1718_313) and approval from the English Breast Research Advisory Committee (BSPRAC_031). The findings will be disseminated to breast screening clinicians (via journal publication and conference presentation), to the NHS Breast Screening Programme to update their guidelines on how women with atypia should be followed up, and to the general public
Forum : Authority, sovereignty, interpretation … subtext? Controversies in recent German historiography
No full textLike other historiographical fields, that of German history has been defined through most of its existence by the things historians argued about. We could go back well over a hundred years to the Methodenstreit over Karl Lamprecht's efforts to write multidisciplinary history, follow the line through the work of Eckart Kehr, Fritz Fischer, Hans Ulrich Wehler, and the Sonderweg debate, and continue on through the Historikerstreit and the Historikerinnenstreit of the 1980s, and the Goldhagen and Wehrmacht exhibit fights in the mid-1990s, to recent debates over the relative weight of colonial and Holocaust memory
Exploring the impact of the HOMO–LUMO gap on molecular thermoelectric properties : a comparative study of conjugated aromatic, quinoidal, and donor–acceptor core systems
Get PDFThermoelectric materials have garnered significant interest for their potential to efficiently convert waste heat into electrical energy at room temperature without moving parts or harmful emissions. This study investigated the impact of the HOMO–LUMO (H-L) gap on the thermoelectric properties of three distinct classes of organic compounds: conjugated aromatics (isoindigos (IIGs)), quinoidal molecules (benzodipyrrolidones (BDPs)), and donor–acceptor systems (bis(pyrrol-2-yl)squaraines (BPSs)). These compounds were chosen for their structural simplicity and linear π-conjugated conductance paths, which promote high electrical conductance and minimize complications from quantum interference. Single-molecule thermoelectric measurements revealed that despite their low H-L gaps, the Seebeck coefficients of these compounds remain low. The alignment of the frontier orbitals relative to the Fermi energy was found to play a crucial role in determining the Seebeck coefficients, as exemplified by the BDP compounds. Theoretical calculations support these findings and suggest that anchor group selection could further enhance the thermoelectric behavior of these types of molecules
Behavioural activation for depressive symptoms in adults with severe to profound intellectual disabilities : modelling and initial feasibility study
Get PDFBackground: Almost no research has been published reporting on evaluations of the effectiveness of psychological interventions for people with severe to profound intellectual disabilities and depression. This paper describes the development and initial feasibility testing of an adapted Behavioural Activation therapy (BeatIt2) for this population. Method: Phase 1 of the study examined participant recruitment and willingness to be randomised in the context of a planned Randomised Controlled Trial (RCT). Phase 2 examined the feasibility of delivering the intervention. Results: Twenty adults with a severe or profound intellectual disability and clinically significant depression were recruited to Phase 1 of the study. In Phase 2, there was 100% participant retention for those recruited to the study at 6‐month follow‐up. The BeatIt2 therapy was reported to be acceptable for participants. Conclusion: COVID disruption meant that it was not possible to complete the planned feasibility RCT. The positive findings suggest that additional evaluation of BeatIt2 is warranted
Do digital technologies enable firms that prioritize sustainability goals to innovate? Empirical evidence from established UK micro‐businesses
Get PDFThis paper examines the importance of sustainability within firms’ strategic goals and its links with innovation in the context of micro‐businesses. Micro‐businesses provide an appropriate context for investigating this relationship because, while they tend to prioritize social and environmental goals, they are also more likely to confront resource constraints that can restrict their capability to innovate. Building on goal‐setting theory and the resource‐based view (RBV) of the firm, we explore under what conditions established micro‐businesses that prioritize sustainability goals are more likely to innovate. Using novel survey data on 4649 established micro‐businesses in the UK, we examine the enabling role of digital technologies. Our results suggest that owner‐managers who prioritize sustainability goals are significantly more likely to generate new product and process innovations. Moreover, we find that this effect is stronger when micro‐businesses adopt digital technologies. Digital technologies enhance the capabilities of micro‐businesses, strengthening the connection between sustainability goals and product and process innovation