Improved Application of Carbon Nanotube Atomic Force Microscopy Probes Using PeakForce Tapping Mode

In this work PeakForce tapping (PFT) imaging was demonstrated with carbon nanotube atomic force microscopy (CNT-AFM) probes; this imaging mode shows great promise for providing simple, stable imaging with CNT-AFM probes, which can be difficult to apply. The PFT mode is used with CNT-AFM probes to demonstrate high resolution imaging on samples with features in the nanometre range, including a Nioprobe calibration sample and gold nanoparticles on silicon, in order to demonstrate the modes imaging effectiveness, and to also aid in determining the diameter of very thin CNT-AFM probes. In addition to stable operation, the PFT mode is shown to eliminate "ringing" artefacts that often affect CNT-AFM probes in tapping mode near steep vertical step edges. This will allow for the characterization of high aspect ratio structures using CNT-AFM probes, an exercise which has previously been challenging with the standard tapping mode

Environmental differences between sites control the diet and nutrition of the carnivorous plant Drosera rotundifolia

Background and aims: Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for Drosera rotundifolia L. Methods: We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.62 g m−2 yr.−1, 353 μg l−1), Whixall Moss (1.37 g m−2 yr.−1, 1505 μg l−1). The total N amount per plant and the contributions of prey/root N to the plants’ N budget were calculated using a single isotope natural abundance method. Results: Plants at Whixall Moss invested less in carnivory, were less likely to capture prey, and were less reliant on prey-derived N (25.5% compared with 49.4%). Actual prey capture did not differ between sites. Diet composition differed – Cors Fochno plants captured 62% greater proportions of Diptera. Conclusions: Our results show site-level differences in plant diet and nutrition consistent with differences in resource availability. Similarity in actual prey capture may be explained by differences in leaf stickiness and prey abundance

Characterisation of the Material and Mechanical Properties of Atomic Force Microscope Cantilevers with a Plan-View Trapezoidal Geometry

Cantilever devices have found applications in numerous scientific fields and instruments, including the atomic force microscope (AFM), and as sensors to detect a wide range of chemical and biological species. The mechanical properties, in particular, the spring constant of these devices is crucial when quantifying adhesive forces, material properties of surfaces, and in determining deposited mass for sensing applications. A key component in the spring constant of a cantilever is the plan-view shape. In recent years, the trapezoidal plan-view shape has become available since it offers certain advantages to fast-scanning AFM and can improve sensor performance in fluid environments. Euler beam equations relating cantilever stiffness to the cantilever dimensions and Young’s modulus have been proven useful and are used extensively to model cantilever mechanical behaviour and calibrate the spring constant. In this work, we derive a simple correction factor to the Euler beam equation for a beam-shaped cantilever that is applicable to any cantilever with a trapezoidal plan-view shape. This correction factor is based upon previous analytical work and simplifies the application of the previous researchers formula. A correction factor to the spring constant of an AFM cantilever is also required to calculate the torque produced by the tip when it contacts the sample surface, which is also dependent on the plan-view shape. In this work, we also derive a simple expression for the torque for triangular plan-view shaped cantilevers and show that for the current generation of trapezoidal plan-view shaped AFM cantilevers, this will be a good approximation. We shall apply both these correction factors to determine Young’s modulus for a range of trapezoidal-shaped AFM cantilevers, which are specially designed for fast-scanning. These types of AFM probes are much smaller in size when compared to standard AFM probes. In the process of analysing the mechanical properties of these cantilevers, important insights are also gained into their spring constant calibration and dimensional factors that contribute to the variability in their spring constant

Photoperiod Regulates Lean Mass Accretion, but Not Adiposity, in Growing F344 Rats Fed a High Fat Diet

yesIn this study the effects of photoperiod and diet, and their interaction, were examined for their effects on growth and body composition in juvenile F344 rats over a 4-week period. On long (16L:8D), relative to short (8L:16D), photoperiod food intake and growth rate were increased, but percentage adiposity remained constant (ca 3-4%). On a high fat diet (HFD), containing 22.8% fat (45% energy as fat), food intake was reduced, but energy intake increased on both photoperiods. This led to a small increase in adiposity (up to 10%) without overt change in body weight. These changes were also reflected in plasma leptin and lipid levels. Importantly while both lean and adipose tissue were strongly regulated by photoperiod on a chow diet, this regulation was lost for adipose, but not lean tissue, on HFD. This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion. Consistent with this both hypothalamic GHRH gene expression and serum IGF-1 levels were photoperiod dependent. As for other animals and humans, there was evidence of central hyposomatotropism in response to obesity, as GHRH gene expression was suppressed by the HFD. Gene expression of hypothalamic AgRP and CRH, but not NPY nor POMC, accorded with the energy balance status on long and short photoperiod. However, there was a general dissociation between plasma leptin levels and expression of these hypothalamic energy balance genes. Similarly there was no interaction between the HFD and photoperiod at the level of the genes involved in thyroid hormone metabolism (Dio2, Dio3, TSHβ or NMU), which are important mediators of the photoperiodic response. These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.Scottish Government (Rural and Environment Science and Analytical Services Division, http://www.scotland.gov.uk/), AWR LR LMT PJM and the BBSRC, (http://www.bbsrc.ac.uk/home/home.aspx, grant BB/K001043/1), AWR GH PJ

Influence of sex, age, pubertal maturation and body mass index on circulating white blood cell counts in healthy European adolescents—the HELENA study

Percentiles 10th, 25th, 50th, 75th and 90th are presented for circulating white blood cells (WBC), neutrophils, lymphocytes, monocytes, eosinophils and basophils in healthy European adolescents (12.5–17.5 years, n = 405, 48.9 % boys), considering age, sex, puberty and body mass index (BMI). CD3+ (mature T cells), CD4+ (T helper), CD8+ (T cytotoxic), CD16+56+ (natural killer), CD19+ (B cells), CD3+CD45RA+, CD4+CD45RA+, CD8+CD45RA+ (naïve), CD3+CD45RO+, CD4+CD45RO+ and CD8+CD45RO+ (memory) lymphocytes were also analysed by immunophenotyping. Girls presented higher WBC, neutrophil, CD3+CD45RO+ and CD4+CD45RO+ cell counts and CD3+/CD19+ ratio, and lower CD3+CD45RA+ and CD4+CD45RA+ counts than boys. Age was associated with higher neutrophil counts and CD3+/CD19+, and lower CD19+ counts; in boys, with lower CD3+CD45RA+, CD4+CD45RA+ and CD8+CD45RA+ counts as well; in girls, with higher WBC, CD3+CD45RO+ and CD4+CD45RO+ counts. Pubertal maturation in boys was associated with lower WBC and lymphocyte counts; in girls, with higher basophil, CD3+CD45RO+ and CD4+CD45RO+ values. BMI was associated with higher WBC counts; in boys, also with higher lymphocyte counts; in girls, with higher neutrophil, CD4+, CD3+CD45RO+ and CD4+CD45RO+ counts. Conclusion: Our study provides normative values for circulating immune cells in adolescents, highlighting the importance of considering sex, age, pubertal maturation and BMI when establishing reference ranges for WBC in paediatric populations

New Pharmacological Agents to Aid Smoking Cessation and Tobacco Harm Reduction: What has been Investigated and What is in the Pipeline?

A wide range of support is available to help smokers to quit and aid attempts at harm reduction, including three first-line smoking cessation medications: nicotine replacement therapy, varenicline and bupropion. Despite the efficacy of these, there is a continual need to diversify the range of medications so that the needs of tobacco users are met. This paper compares the first-line smoking cessation medications to: 1) two variants of these existing products: new galenic formulations of varenicline and novel nicotine delivery devices; and 2) twenty-four alternative products: cytisine (novel outside of central and eastern Europe), nortriptyline, other tricyclic antidepressants, electronic cigarettes, clonidine (an anxiolytic), other anxiolytics (e.g. buspirone), selective 5-hydroxytryptamine (5-HT) reuptake inhibitors, supplements (e.g. St John’s wort), silver acetate, nicobrevin, modafinil, venlafaxine, monoamine oxidase inhibitors (MAOI), opioid antagonist, nicotinic acetylcholine receptors (nAChR) antagonists, glucose tablets, selective cannabinoid type 1 receptor antagonists, nicotine vaccines, drugs that affect gamma-aminobutyric acid (GABA) transmission, drugs that affect N-methyl-D-aspartate receptors (NMDA), dopamine agonists (e.g. levodopa), pioglitazone (Actos; OMS405), noradrenaline reuptake inhibitors, and the weight management drug lorcaserin. Six criteria are used: relative efficacy, relative safety, relative cost, relative use (overall impact of effective medication use), relative scope (ability to serve new groups of patients), and relative ease of use (ESCUSE). Many of these products are in the early stages of clinical trials, however, cytisine looks most promising in having established efficacy and safety and being of low cost. Electronic cigarettes have become very popular, appear to be efficacious and are safer than smoking, but issues of continued dependence and possible harms need to be considered

Efficient and Fast Synthesis of Few-Layer Black Phosphorus via Microwave-Assisted Liquid-Phase Exfoliation

High‐quality, few‐layer black‐phosphorus (BP) flakes are prepared in a common organic solvent with very short processing times using microwave‐assisted liquid‐phase exfoliation. A comprehensive range of analysis, combined with density‐functional theory calculations, confirms that the product prepared using the microwave technique is few‐layer BP with small‐ and large‐area flakes. The suspended exfoliated BP sheets show excellent stability, while samples dispersed onto silicon from the suspensions exhibit low oxidation levels after several days in ambient conditions. This straightforward synthesis method is facile, efficient, and extremely fast, and does not involve use of any surfactant or ultrasonication steps and will facilitate future development of phosphorene research

The Effectiveness and Cost-Effectiveness of a Universal Digital Parenting Intervention Designed and Implemented During the COVID-19 Pandemic: Evidence From a Rapid-Implementation Randomized Controlled Trial Within a Cohort

Background: Children’s conduct and emotional problems increased during the COVID-19 pandemic. Objective: We tested whether a smartphone parenting support app, Parent Positive, developed specifically for this purpose, reversed these effects in a cost-effective way. Parent Positive includes 3 zones. Parenting Boosters (zone 1) provided content adapted from standard face-to-face parent training programs to tackle 8 specific challenges identified by parents and parenting experts as particularly relevant for parents during the pandemic. The Parenting Exchange (zone 2) was a parent-to-parent and parent-to-expert communication forum. Parenting Resources (zone 3) provided access to existing high-quality web-based resources on a range of additional topics of value to parents (eg, neurodevelopmental problems, diet, and sleep). Methods: Supporting Parents And Kids Through Lockdown Experiences (SPARKLE), a randomized controlled trial, was embedded in the UK-wide COVID-19: Supporting Parents, Adolescents and Children during Epidemics (Co-SPACE) longitudinal study on families’ mental health during the pandemic. Parents of children aged 4 to 10 years were randomized 1:1 to Parent Positive or follow-up as usual (FAU) between May 19, 2021, and July 26, 2021. Parent Positive provided advice on common parenting challenges and evidence-based web-based resources and facilitated parent-to-parent and expert-to-parent support. Child conduct and emotional problems and family well-being were measured before randomization (T1) and at 1 (T2) and 2 (T3) months after randomization. Service use, costs, and adverse events were measured, along with app use and satisfaction. The primary outcome was T2 parent-reported child conduct problems, which were analyzed using linear mixed regression models. Results: A total of 320 participants were randomized to Parent Positive, and 326 were randomized to FAU. The primary outcome analysis included 79.3% (512/646) of the participants (dropout: 84/320, 26% on Parent Positive and 50/326, 15% on FAU). There were no statistically significant intervention effects on conduct problems at either T2 (standardized effect=−0.01) or T3 (secondary outcome; standardized effect=−0.09) and no moderation by baseline conduct problems. Significant intervention-related reductions in emotional problems were observed at T2 and T3 (secondary outcomes; standardized effect=−0.13 in both cases). Parent Positive, relative to FAU, was associated with more parental worries at T3 (standardized effect=0.14). Few intervention-attributable adverse events were reported. Parent Positive was cost-effective once 4 outliers with extremely high health care costs were excluded. Conclusions: Parent Positive reduced child emotional problems and was cost-effective compared with FAU once outliers were removed. Although small when considered against targeted therapeutic interventions, the size of these effects was in line with trials of nontargeted universal mental health interventions. This highlights the public health potential of Parent Positive if implemented at the community level. Nevertheless, caution is required before making such an interpretation, and the findings need to be replicated in large-scale, whole-community studies

Supporting Parents & Kids Through Lockdown Experiences (SPARKLE): a digital parenting support app implemented in an ongoing general population cohort study during the COVID-19 pandemic: a structured summary of a study protocol for a randomised controlled trial

Objectives The COVID-19 related lockdowns and distancing measures have presented families with unprecedented challenges. A UK-wide cohort study tracking changes in families’ mental health since early lockdown (Co-SPACE) found a significant rise in primary school-aged children’s behaviour problems and associated family-related stress. Three-quarters of parents in Co-SPACE also reported wanting extra support. In SPARKLE, we will examine whether providing Co-SPACE families with a smartphone application delivering information and parenting support, Parent Positive, can reverse the negative effects of the pandemic on children and parents. The efficacy on child and parent outcomes and cost-effectiveness of Parent Positive will be examined. We will also test whether the effects are moderated by pre-existing levels of child conduct problems and usage of Parent Positive. Exploratory analyses will examine whether other baseline characteristics or lockdown circumstances moderate the effects of Parent Positive. Trial design SPARKLE is a two-arm superiority parallel group randomised controlled trial embedded in an existing large UK-wide self-selected community cohort – Co-SPACE. Those who consent to SPARKLE will be randomised 1:1 to either Parent Positive or Follow-up As Usual (FAU). Participants Co-SPACE (a UK-wide longitudinal cohort study) parents aged ≥18 who have children aged 4-10 years will be eligible for SPARKLE. Intervention and comparator Parent Positive: is a digital public health intervention that can be delivered rapidly at scale to support parents in managing their children’s behaviour to reduce conduct problems and levels of family conflict, which were exacerbated during the first lockdown, and which may increase further in future months as families need to cope with continuous uncertainty and further disruption to their daily lives. Co-designed with parents and based on decades of parenting research, Parent Positive consists of three elements: (i) Parenting Boosters: where advice, delivered in the form of narrated animations, videos, graphics and text is provided to help parents with eight common parenting challenges; (ii) Parenting Exchange: a facilitated parent-to-parent communication and peer support platform and; (iii) Parent Resources: giving access to carefully selected high-quality, evidence-based online parenting resources. Follow-up as Usual: FAU was selected as a comparator because the public health nature meant that an active comparator was not appropriate due to the pragmatic, rapid implementation of the trial. Individuals randomised to FAU will receive no intervention for the first two months while the data for baseline (T1), T2 and T3 are collected. They will then be given full access to the app until 30th November 2021. Main outcomes Outcome measures will be collected remotely through Qualtrics according to the Co-SPACE schedule at baseline (T1), which will be the Co-SPACE survey data obtained immediately prior to randomisation, and then at one month (T2) and two months (T3) post-randomisation. Measures will be collected to assess group differences in child and parent outcomes, costs and service utilisation, and adverse events. Usage of Parent Positive will also be tracked. The primary outcome is parent-reported child conduct problems at one-month post-randomisation measured using the Strengths and Difficulties Questionnaire conduct problems subscale. Randomisation Enrolled participants will be allocated to Parent Positive or FAU at the ratio of 1:1 by simple randomisation using the Randomizer function within the Qualtrics programme. Neither blocking nor stratification will be used. Blinding (masking) It is not possible to blind parents enrolled in the study and Qualtrics will automatically inform parents of their group allocation. Blinded members of the research team and the senior statistician will not be given access to the Qualtrics system or the data in order to remain blinded until after the analysis is complete. We do not anticipate any serious harms associated with taking part in the intervention, therefore there will be no need to unblind any blinded staff during the study. The junior statistician will be unblinded throughout. Numbers to be randomised (sample size) A total of 616 will be recruited into the trial with 308 consenting parents randomised to each treatment arm. Trial status V1.0; 15.03.2021. Not yet recruiting. Anticipated start date: 1st April 2021. Anticipated end date for recruitment: 31st July 2021. Trial registration Clinicaltrial.gov: NCT04786080. The trial was prospectively registered on 8 March 2021. Full protocol The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2)