Condensation of a tetrahedra rigid-body libration mode in HoBaCo4O7 : the origin of phase transition at 355 K

Rietveld profiles, Moessbauer spectra and x-ray absorption fine structure (XAFS) were analyzed through the structural phase transition at Ts = 355 K in HoBaCo4O7. Excess of the oxygen content over O7 was avoided via annealing the samples in argon flow at 600 degree C. Space groups (S.G.) Pbn21c and P63mc were used to refine the structure parameters in the low- and high-temperature phases, respectively. Additionally, the Cmc21 symmetry was considered as a concurrent model of structure of the low-temperature phase. In the high-temperature phase, severe anisotropy of thermal motion of the major part of the oxygen atoms was observed. This anisotropic motion turns to be quenched as the sample is cooled below Ts. The variation of quadrupole splitting near Ts is not similar to a steplike anomaly frequently seen at the charge-ordering transition. We observe instead a dip-like anomaly of the average quadrupole splitting near Ts. Narrow distribution of the electric field gradient (EFG) over different cobalt sites is observed and explained on the basis of point-charge model. XAFS spectra show no evidence of significant difference between YBaCo4O7 (T > Ts) and HoBaCo4O7 (T < Ts). The origin of the transition at Ts is ascribed to the condensation of the libration phonon mode associated with the rigid-body rotational movements of the starlike tetrahedral units, the building blocks of kagome network. It is shown that the condensation of the libration mode is not compatible with translation symmetry for the hexagonal S.G., but compatible for the orthorhombic S.G. The orthorhombic lattice parameters and EFG components (Vxx, Vyy, Vzz) vary smoothly with temperature at approaching Ts and closely follow each other.Comment: 13 figure

A prospective multicentre study in Sweden and Norway of mental distress and psychiatric morbidity in head and neck cancer patients

A Swedish/Norwegian head and neck cancer study was designed to assess prospectively the levels of mental distress and psychiatric morbidity in a heterogeneous sample of newly diagnosed head and neck cancer patients. A total of 357 patients were included. The mean age was 63 years, and 72% were males. The patients were asked to answer the HAD scale (the Hospital Anxiety and Depression scale) six times during 1 year. The number of possible or probable cases of anxiety or depression disorder was calculated according to standardized cut-offs. Approximately one-third of the patients scored as a possible or probable case of a major mood disorder at each measurement point during the study year. There were new cases of anxiety or depression at each time point. The anxiety level was highest at diagnosis, while depression was most common during treatment. Females were more anxious than males at diagnosis, and patients under 65 years of age scored higher than those over 65. Patients with lower performance status and more advanced disease reported higher levels of mental distress and more often scored as a probable or possible cases of psychiatric disorder. Our psychometric analyses supported the two-dimensional structure and stability of the HAD scale. The HAD scale seems to be the method of choice for getting valid information about the probability of mood disorder in head and neck cancer populations. The prevalence of psychiatric morbidity found in this study emphasizes the importance of improved diagnosis and treatment

Comparative analysis of discrete exosome fractions obtained by differential centrifugation

Background: Cells release a mixture of extracellular vesicles, amongst these exosomes, that differ in size, density and composition. The standard isolation method for exosomes is centrifugation of fluid samples, typically at 100,000×g or above. Knowledge of the effect of discrete ultracentrifugation speeds on the purification from different cell types, however, is limited. Methods: We examined the effect of applying differential centrifugation g-forces ranging from 33,000×g to 200,000×g on exosome yield and purity, using 2 unrelated human cell lines, embryonic kidney HEK293 cells and bladder carcinoma FL3 cells. The fractions were evaluated by nanoparticle tracking analysis (NTA), total protein quantification and immunoblotting for CD81, TSG101, syntenin, VDAC1 and calreticulin. Results: NTA revealed the lowest background particle count in Dulbecco's Modified Eagle's Medium media devoid of phenol red and cleared by 200,000×g overnight centrifugation. The centrifugation tube fill level impacted the sedimentation efficacy. Comparative analysis by NTA, protein quantification, and detection of exosomal and contamination markers identified differences in vesicle size, concentration and composition of the obtained fractions. In addition, HEK293 and FL3 vesicles displayed marked differences in sedimentation characteristics. Exosomes were pelleted already at 33,000×g, a g-force which also removed most contaminating microsomes. Optimal vesicle-to-protein yield was obtained at 67,000×g for HEK293 cells but 100,000×g for FL3 cells. Relative expression of exosomal markers (TSG101, CD81, syntenin) suggested presence of exosome subpopulations with variable sedimentation characteristics. Conclusions: Specific g-force/k factor usage during differential centrifugation greatly influences the purity and yield of exosomes. The vesicle sedimentation profile differed between the 2 cell lines

Implementation of neck/shoulder exercises for pain relief among industrial workers: A randomized controlled trial

BACKGROUND: Although leisure-time physical activity is important for health, adherence to regular exercise is challenging for many adults. The workplace may provide an optimal setting to reach a large proportion of the adult population needing regular physical exercise. This study evaluates the effect of implementing strength training at the workplace on non-specific neck and shoulder pain among industrial workers. METHODS: Cluster-randomized controlled trial involving 537 adults from occupations with high prevalence of neck and shoulder pain (industrial production units). Participants were randomized to 20 weeks of high-intensity strength training for the neck and shoulders three times a week (n = 282) or a control group receiving advice to stay physically active (n = 255). The strength training program followed principles of progressive overload and periodization. The primary outcome was changes in self-reported neck and shoulder pain intensity (scale 0-9). RESULTS: 85% of the participants followed the strength training program on a weekly basis. In the training group compared with the control group, neck pain intensity decreased significantly (-0.6, 95% CI -1.0 to -0.1) and shoulder pain intensity tended to decrease (-0.2, 95% CI -0.5 to 0.1, P = 0.07). For pain-cases at baseline (pain intensity > = 3) the odds ratio - in the training group compared with the control group - for being a non-case at follow-up (pain intensity < 3) was 2.0 (95% CI 1.0 to 4.2) for the neck and 3.9 (95% CI 1.7 to 9.4) for the shoulders. CONCLUSION: High-intensity strength training relying on principles of progressive overload can be successfully implemented at industrial workplaces, and results in significant reductions of neck and shoulder pain. TRIAL REGISTRATION: NCT01071980

The Effects of Carbon Dioxide Removal on the Carbon Cycle

Increasing atmospheric CO2 is having detrimental effects on the Earth system. Societies have recognized that anthropogenic CO2 release must be rapidly reduced to avoid potentially catastrophic impacts. Achieving this via emissions reductions alone will be very difficult. Carbon dioxide removal (CDR) has been suggested to complement and compensate for insufficient emissions reductions, through increasing natural carbon sinks, engineering new carbon sinks, or combining natural uptake with engineered storage. Here, we review the carbon cycle responses to different CDR approaches and highlight the often-overlooked interaction and feedbacks between carbon reservoirs that ultimately determines CDR efficacy. We also identify future research that will be needed if CDR is to play a role in climate change mitigation, these include coordinated studies to better understand (i) the underlying mechanisms of each method, (ii) how they could be explicitly simulated, (iii) how reversible changes in the climate and carbon cycle are, and (iv) how to evaluate and monitor CDR

Renewable energy resource assessment

© The Author(s) 2019. Literature overview of published global and regional renewable energy potential estimates. This section provides definitions for different types of RE potentials and introduces a new category, the economic renewable energy potential in space constrained environments. The potential for utility scale solar and onshore wind in square kilometre and maximum possible installed capacity (in GW) are provided for 75 different regions. The results set the upper limits for the deployment of solar- and wind technologies for the development of the 2.0 °C and 1.5 °C energy pathways

Efficient precision quantization in AdS/CFT

Understanding finite-size effects is one of the key open questions in solving planar AdS/CFT. In this paper we discuss these effects in the AdS_5xS^5 string theory at one-loop in the world-sheet coupling. First we provide a very general, efficient way to compute the fluctuation frequencies, which allows to determine the energy shift for very general multi-cut solutions. Then we apply this to two-cut solutions, in particular the giant magnon and determine the finite-size corrections at subleading order. The latter are then compared to the finite-size corrections from Luscher-Klassen-Melzer formulas and found to be in perfect agreement.Comment: 32 pages, 5 figures; v2: typos corrected, refs adde