Liquid-induced damping of mechanical feedback effects in single electron tunneling through a suspended carbon nanotube

In single electron tunneling through clean, suspended carbon nanotube devices at low temperature, distinct switching phenomena have regularly been observed. These can be explained via strong interaction of single electron tunneling and vibrational motion of the nanotube. We present measurements on a highly stable nanotube device, subsequently recorded in the vacuum chamber of a dilution refrigerator and immersed in the 3He/4He mixture of a second dilution refrigerator. The switching phenomena are absent when the sample is kept in the viscous liquid, additionally supporting the interpretation of dc-driven vibration. Transport measurements in liquid helium can thus be used for finite bias spectroscopy where otherwise the mechanical effects would dominate the current.Comment: 4 pages, 3 figure

Negative frequency tuning of a carbon nanotube nano-electromechanical resonator

A suspended, doubly clamped single wall carbon nanotube is characterized as driven nano-electromechanical resonator at cryogenic temperatures. Electronically, the carbon nanotube displays small bandgap behaviour with Coulomb blockade oscillations in electron conduction and transparent contacts in hole conduction. We observe the driven mechanical resonance in dc-transport, including multiple higher harmonic responses. The data shows a distinct negative frequency tuning at finite applied gate voltage, enabling us to electrostatically decrease the resonance frequency to 75% of its maximum value. This is consistently explained via electrostatic softening of the mechanical mode.Comment: 4 pages, 4 figures; submitted for the IWEPNM 2013 conference proceeding

Results of special mechanical analyses of Luna 16 material

The studies carried out on the Luna 16 regolith have confirmed the data that were already published internationally. By means of activation analysis under irradiation in the reactor, activation analysis with a 14 MeV U-generator, and mass spectroscopy on samples of 10 or 20 mg, six main and 63 trace elements were quantitatively determined and compared with known data

What can we learn from geographical comparisons of childhood cancer survival?

With improvements in treatment for childhood cancer, comparisons of survival rates between countries have become important to inform future health policies and treatment strategies. Population-based cancer registry data are viewed as the gold standard for such comparisons, but even these have potential confounding factors. Here, we review the interpretation of recent geographical comparisons of childhood cancer survival from the viewpoint of the British Isles, a region with a 45-year record of national population-based cancer registration and a national childhood cancer clinical trials organisation in place for nearly 30 years. Using national data on referral patterns to tertiary paediatric oncology centres, we explore some of the reasons for lower survival rates in the past for some tumour groups and anticipate continued improvement in the next decade. Participation in international clinical trials coincided with rapid gains in survival for hepatoblastoma. This exemplifies the potential benefits of international collaborative clinical research, particularly for rare subgroups

Large-Eddy Simulation of inhomogeneous canopy flows using high resolution terrestrial laser scanning data

The effect of sub-tree forest heterogeneity in the flow past a clearing is investigated by means of large-eddy simulation (LES). For this purpose, a detailed representation of the canopy has been acquired by terrestrial laser scanning for a patch of approximately 190m length in the field site “Tharandter Wald”, near the city of Dresden, Germany. The scanning data are used to produce a high resolution plant area distribution (PAD) that is averaged over approximately one tree height (30m) along the transverse direction, in order to simplify the LES study. Despite the smoothing involved with this procedure, the resulting two-dimensional PAD maintains a rich vertical and horizontal structure. For the LES study, the PAD is embedded in a larger domain covered with an idealized, horizontally homogeneous canopy. Simulations are performed for neutral conditions and compared to a LES with homogeneous PAD and recent field measurements. The results reveal a considerable influence of small-scale plant distribution on the mean velocity field as well as on turbulence data. Particularly near the edges of the clearing, where canopy structure is highly variable, usage of a realistic PAD appears to be crucial for capturing the local flow structure. Inside the forest, local variations in plant density induce a complex pattern of upward and downward motions, which remain visible in the mean flow and make it difficult to identify the “adjustment zone” behind the windward edge of the clearing

Large-Eddy Simulation Study of the Effects on Flow of a Heterogeneous Forest at Sub-tree Resolution

Abstract The effect of three-dimensional plant heterogeneity on flow past a clearing is investigated by means of large-eddy simulation. A detailed representation of the canopy has been acquired by terrestrial laser scanning for a patch of approximately 328m length and 172m width at the field site “TharandterWald”, near the city of Dresden, Germany. The scanning data are used to produce a highly resolved, three-dimensional plant area distribution representing the actual canopy. Hence, the vegetation maintains a rich horizontal and vertical structure including the three-dimensional clearing. The scanned plant area density is embedded in a larger domain, which is filled with a heterogeneous forest generated by the virtual canopy generator of Bohrer et al. (Tellus B 59:566–576, 2007). Based on forest inventory maps and airborne laser scanning, the characteristics of the actual canopy are preserved. Furthermore, the topography is extracted from a digital terrain model with some modifications to accommodate for periodic boundary conditions. A large-eddy simulation is performed for neutral atmospheric conditions and compared to simulations of a two-dimensional plant area density and an one-year-long field experiment conducted at the corresponding field site. The results reveal a considerable influence of the plant heterogeneity on the mean velocity field as well as on the turbulent quantities. The three-dimensional environment, e.g., the oblique edges combined with horizontal and vertical variations in plant area density and the topography create a sustained vertical and cross-flow velocity. Downstream of the windward forest edge an enhanced gust zone develops, whose intensity and relative position are influenced by the local canopy density and, therefore, is not constant along the edge. These results lead us to the conclusion that the usage of a three-dimensional plant area distribution is essential for capturing the flow features inside the canopy and within the mixing layer above

Are survival and mortality rates associated with recruitment to clinical trials in teenage and young adult patients with acute lymphoblastic leukaemia? A retrospective observational analysis in England

Objective: Participation rates in clinical trials are low in teenagers and young adults (TYA) with cancer. Whilst the importance of clinical trials in informing best practice is well established, data regarding individual patient benefit are scarce. We have investigated the association between overall survival and trial recruitment in TYA patients with acute lymphoblastic leukaemia (ALL). Design: Retrospective. Setting: National (England) TYA patients treated for ALL. Participants: 511 patients aged 15–24 years diagnosed with ALL between 2004 and 2010 inclusive, of whom 239 (46.7%) participated in the UKALL2003 trial. Outcome measures: Patients were identified using National Clinical Trial (UKALL2003) and Cancer Registry (National Cancer Data Repository, English National Cancer Online Registration Environment) Databases. Relative survival rates were calculated for trial and non-trial patients and observed differences were modelled using a multiple regression approach. The numbers and percentages of deaths in those patients included in the survival analysis were determined for each 3-month period, p values were calculated using the two-tailed z-test for difference between proportions and 95% CIs for percentage deaths were derived using the binomial distribution based on the Wilson Score method. Results: Patients treated on the trial had a 17.9% better 2-year survival (85.4% vs 67.5%, p<0.001) and 8.9% better 1-year survival (90.8% vs 81.9%, p=0.004) than those not on the trial. 35 (14.6%) patients recruited to the trial died in the 2 years following diagnosis compared with 86 (32.6%) of those not recruited (p<0.001). Conclusions: TYA patients recruited to the clinical trial UKALL 2003 in England had a lower risk of mortality and a higher overall survival than contemporaneous non-trial patients. These data underline the potential for individual patient benefit in participating in a clinical trial and the importance of international efforts to increase trial participation in the TYA age group. Trial registration number: ISRCTN07355119

Effect of rapidly resorbable bone substitute materials on the temporal expression of the osteoblastic phenotype \u3cem\u3ein vitro\u3c/em\u3e

Ideally, bioactive ceramics for use in alveolar ridge augmentation should possess the ability to activate bone formation and, thus, cause the differentiation of osteoprogenitor cells into osteoblasts at their surfaces. Therefore, in order to evaluate the osteogenic potential of novel bone substitute materials, it is important to examine their effect on osteoblastic differentiation. This study examines the effect of rapidly resorbable calcium–alkali– orthophosphates on osteoblastic phenotype expression and compares this behavior to that of ß-tricalcium phosphate (TCP) and bioactive glass 45S5. Test materials were three materials (denominated GB14, GB9, GB9/25) with a crystalline phase Ca2KNa(PO4)2 and with a small amorphous portion containing either magnesium potassium phosphate (GB14) or silica phosphate (GB9 and GB9/25, which also contains Ca2P2O7); and a material with a novel crystalline phase Ca10[K/Na](PO4)7 (material denominated 352i). SaOS-2 human bone cells were grown on the substrata for 3, 7, 14, and 21 days, counted, and probed for an array of osteogenic markers. GB9 had the greatest stimulatory effect on osteoblastic proliferation and differentiation, suggesting that this material possesses the highest potency to enhance osteogenesis. GB14 and 352i supported osteoblast differentiation to the same or a higher degree than TCP, whereas, similar to bioactive glass 45S5, GB9/25 displayed a greater stimulatory effect on osteoblastic phenotype expression, indicating that GB9/25 is also an excellent material for promoting osteogenesis

The HealtheSteps™ lifestyle prescription program to improve physical activity and modifiable risk factors for chronic disease: a pragmatic randomized controlled trial.

BACKGROUND: Our objective was to determine the influence of the HealtheSteps™ lifestyle prescription program on physical activity and modifiable risk factors for chronic disease in individuals at risk. METHODS: One hundred eighteen participants were recruited from 5 sites in Southwestern Ontario, Canada and randomized to either the intervention (HealtheSteps™ program, n = 59) or a wait-list control group (n = 59). The study comprised three phases: an Active Phase (0 to 6 months) consisted of bi-monthly in-person lifestyle coaching with access to a suite of eHealth technology supports (Heathesteps app, telephone coaching and a private HealtheSteps™ social network) followed by a Minimally-Supported Phase I (6 to 12 months), in which in-person coaching was removed, but participants still had access to the full suite of eHealth technology supports. In the final stage, Minimally-Supported Phase II (12 to 18 months), access to the eHealth technology supports was restricted to the HealtheSteps™ app. Assessments were conducted at baseline, 6, 12 and 18 months. The study primary outcome was the 6-month change in average number of steps per day. Secondary outcomes included: self-reported physical activity and sedentary time; self-reported eating habits; weight and body composition measures; blood pressure and health-related quality of life. Data from all participants were analyzed using an intent-to-treat approach. We applied mixed effects models for repeated measurements and adjusted for age, sex, and site in the statistical analyses. RESULTS: Participants in HealtheSteps™ increased step counts (between-group [95% confidence interval]: 3132 [1969 to 4294], p \u3c 0.001), decreased their sitting time (- 0.08 [- 0.16 to - 0.006], p = 0.03), and improved their overall healthful eating (- 1.5 [- 2.42 to - 0.58], p = 0.002) to a greater extent compared to control at 6 months. Furthermore, exploratory results showed that these individuals maintained these outcomes 12 months later, after a minimally-supported phase; and retained improvements in sedentary time and improved healthful eating after 18 months. No differences in self-reported physical activity, health-related quality of life, weight, waist circumference or blood pressure were observed between groups at 6 months. CONCLUSIONS: Our findings suggest that HealtheSteps™ is effective at increasing physical activity (i.e., step counts per day), decreasing weekday sitting time, and improving healthful eating in adults at increased risk for chronic disease after 6 months; however, we did not see change in other risk factors. Nonetheless, the maintenance of these behaviours with minimal support after 12 and even 18 months indicates the promise of HealtheSteps™ for long-term sustainability. TRIAL REGISTRATION: The trial was registered on April 6, 2015 with ClinicalTrials.gov (identifier: NCT02413385 )

Logical design of yield pillar base in longwall mining

Longwall is one of the most widely used methods in mining horizontal and gently dipping coal seams. It is a high production method that requires high initial capital investment. Such characteristics enhance the importance of initial design and hence design process. The entries on both sides of the face are integral parts of the method whose accurate design adds to increased profitability and safety of the mining operation. In this paper, two strain-softening models based on analytical fundamentals have been adopted. These models have been applied to a series of yield chain pillars in a coal seam with the depth of 700 meters. Results obtained from this analysis show that such models can be used in deep coal mining and they produce optimum design dimensions and hence they could be adopted as a valid base for logical design of chain pillars. Finally, sensitivity analysis of the results shows that the final design is highly sensitive to the pillar behavior after the coal peak strength. This further demonstrates the validity of the method as a useful tool in designing pillars in longwall deep coal mining