Multielement solid solution alloys are intrinsically disordered on the atomic scale, and many of their advanced properties originate from the local structural characteristics. The local structure of ...a NiCoCr solid solution alloy is measured with x-ray or neutron total scattering and extended x-ray absorption fine structure (EXAFS) techniques. The atomic pair distribution function analysis does not exhibit an observable structural distortion. However, an EXAFS analysis suggests that the Cr atoms are favorably bonded with Ni and Co in the solid solution alloys. This short-range order (SRO) may make an important contribution to the low values of the electrical and thermal conductivities of the Cr-alloyed solid solutions. In addition, an EXAFS analysis of Ni ion irradiated samples reveals that the degree of SRO in NiCoCr alloys is enhanced after irradiation.
Summary Background Paralysis or amputation of an arm results in the loss of the ability to orient the hand and grasp, manipulate, and carry objects, functions that are essential for activities of ...daily living. Brain–machine interfaces could provide a solution to restoring many of these lost functions. We therefore tested whether an individual with tetraplegia could rapidly achieve neurological control of a high-performance prosthetic limb using this type of an interface. Methods We implanted two 96-channel intracortical microelectrodes in the motor cortex of a 52-year-old individual with tetraplegia. Brain–machine-interface training was done for 13 weeks with the goal of controlling an anthropomorphic prosthetic limb with seven degrees of freedom (three-dimensional translation, three-dimensional orientation, one-dimensional grasping). The participant's ability to control the prosthetic limb was assessed with clinical measures of upper limb function. This study is registered with ClinicalTrials.gov , NCT01364480. Findings The participant was able to move the prosthetic limb freely in the three-dimensional workspace on the second day of training. After 13 weeks, robust seven-dimensional movements were performed routinely. Mean success rate on target-based reaching tasks was 91·6% (SD 4·4) versus median chance level 6·2% (95% CI 2·0–15·3). Improvements were seen in completion time (decreased from a mean of 148 s SD 60 to 112 s 6) and path efficiency (increased from 0·30 0·04 to 0·38 0·02). The participant was also able to use the prosthetic limb to do skilful and coordinated reach and grasp movements that resulted in clinically significant gains in tests of upper limb function. No adverse events were reported. Interpretation With continued development of neuroprosthetic limbs, individuals with long-term paralysis could recover the natural and intuitive command signals for hand placement, orientation, and reaching, allowing them to perform activities of daily living. Funding Defense Advanced Research Projects Agency, National Institutes of Health, Department of Veterans Affairs, and UPMC Rehabilitation Institute.
Success Criteria in Implant Dentistry Papaspyridakos, P.; Chen, C.-J.; Singh, M. ...
Journal of dental research,
03/2012, Letnik:
91, Številka:
3
Journal Article
Recenzirano
The purpose of this study was to examine the most frequently used criteria to define treatment success in implant dentistry. An electronic MEDLINE/PubMED search was conducted to identify randomized ...controlled trials and prospective studies reporting on outcomes of implant dentistry. Only studies conducted with roughened surface implants and at least five-year follow-up were included. Data were analyzed for success at the implant level, peri-implant soft tissue, prosthetics, and patient satisfaction. Most frequently reported criteria for success at the implant level were mobility, pain, radiolucency, and peri-implant bone loss (> 1.5 mm), and for success at the peri-implant soft-tissue level, suppuration, and bleeding. The criteria for success at the prosthetic level were the occurrence of technical complications/prosthetic maintenance, adequate function, and esthetics during the five-year period. The criteria at patient satisfaction level were discomfort and paresthesia, satisfaction with appearance, and ability to chew/taste. Success in implant dentistry should ideally evaluate a long-term primary outcome of an implant-prosthetic complex as a whole.
A charge-density wave (CDW) state has a broken symmetry described by a complex order parameter with an amplitude and a phase. The conventional view, based on clean, weak-coupling systems, is that a ...finite amplitude and long-range phase coherence set in simultaneously at the CDW transition temperature T(cdw). Here we investigate, using photoemission, X-ray scattering and scanning tunnelling microscopy, the canonical CDW compound 2H-NbSe2 intercalated with Mn and Co, and show that the conventional view is untenable. We find that, either at high temperature or at large intercalation, CDW order becomes short-ranged with a well-defined amplitude, which has impacts on the electronic dispersion, giving rise to an energy gap. The phase transition at T(cdw) marks the onset of long-range order with global phase coherence, leading to sharp electronic excitations. Our observations emphasize the importance of phase fluctuations in strongly coupled CDW systems and provide insights into the significance of phase incoherence in 'pseudogap' states.
Summary
There is no clear consensus on definition, cut-points or standardised assessments of sarcopenia. We found a lower limb strength assessment was at least as effective in predicting balance, ...mobility and falls in 419 older people as muscle mass-based measures of sarcopenia.
Introduction
There is currently no consensus on the definition, cut-points or standardised assessments of sarcopenia. This study aimed to investigate whether several published definitions of sarcopenia differentiate between older people with respect to important functional and health outcomes.
Methods
Four hundred nineteen community-living older adults (mean age 81.2 ± 4.5, 49 % female) completed assessments of body composition (dual-energy X-ray absorptiometry), strength, balance, mobility and disability. Falls were recorded prospectively for a year using monthly calendars. Sarcopenia was defined according to four skeletal mass-based definitions, two strength-based definitions (handgrip or knee extensor force) and a consensus algorithm (low mass and low strength or slow gait speed). Obesity was defined according to percentage fat mass or waist circumference.
Results
The four skeletal mass-based definitions varied considerably with respect to the percentage of participants classified as sarcopenic and their predictive accuracy for functional and health outcomes. The knee extension strength-based definition was equivalent to or better than the mass-based and consensus algorithm definitions; i.e. weaker participants performed poorly in tests of leaning balance, stepping reaction time, gait speed and mobility. They also had higher physiological fall risk scores and were 43 % more likely to fall at home than their stronger counterparts. Adding obesity to sarcopenia definitions identified participants with greater self-reported disability.
Conclusions
A simple lower limb strength assessment was at least as effective in predicting balance, functional mobility and falls in older people as more expensive and time-consuming muscle mass-based measures. These findings imply that functional terms such as muscle weakness or motor impairment are preferable to sarcopenia.
Background
Genetic susceptibility and environmental influences are important contributors to the development of asthma and atopic diseases. Epigenetic mechanisms may facilitate gene by environment ...interactions in these diseases.
Methods
We studied the rural birth cohort PASTURE (Protection against allergy: study in rural environments) to investigate (a) whether epigenetic patterns in asthma candidate genes are influenced by farm exposure in general, (b) change over the first years of life, and (c) whether these changes may contribute to the development of asthma. DNA was extracted from cord blood and whole blood collected at the age of 4.5 years in 46 samples per time point. DNA methylation in 23 regions in ten candidate genes (ORMDL1, ORMDL2, ORMDL3, CHI3L1, RAD50, IL13, IL4, STAT6, FOXP3, and RUNX3) was assessed by pyrosequencing, and differences between strata were analyzed by nonparametric Wilcoxon–Mann–Whitney tests.
Results
In cord blood, regions in ORMDL1 and STAT6 were hypomethylated in DNA from farmers' as compared to nonfarmers' children, while regions in RAD50 and IL13 were hypermethylated (lowest P‐value (STAT6) = 0.001). Changes in methylation over time occurred in 15 gene regions (lowest P‐value (IL13) = 1.57*10−8). Interestingly, these differences clustered in the genes highly associated with asthma (ORMDL family) and IgE regulation (RAD50, IL13, and IL4), but not in the T‐regulatory genes (FOXP3, RUNX3).
Conclusions
In this first pilot study, DNA methylation patterns change significantly in early childhood in specific asthma‐ and allergy‐related genes in peripheral blood cells, and early exposure to farm environment seems to influence methylation patterns in distinct genes.
Infections with carbapenem-resistant
(CRE) are increasingly being reported from patients in healthcare settings. They are associated with high patient morbidity, attributable mortality and hospital ...costs. Patients who are "at-risk" may be carriers of these multidrug-resistant
(MDR-E).The purpose of this guidance is to raise awareness and identify the "at-risk" patient when admitted to a healthcare setting and to outline effective infection prevention and control measures to halt the entry and spread of CRE.
The guidance was created by a group of experts who were functioning independently of their organisations, during two meetings hosted by the European Centre for Disease Prevention and Control. A list of epidemiological risk factors placing patients "at-risk" for carriage with CRE was created by the experts. The conclusions of a systematic review on the prevention of spread of CRE, with the addition of expert opinion, were used to construct lists of core and supplemental infection prevention and control measures to be implemented for "at-risk" patients upon admission to healthcare settings.
Individuals with the following profile are "at-risk" for carriage of CRE: a) a history of an overnight stay in a healthcare setting in the last 12 months, b) dialysis-dependent or cancer chemotherapy in the last 12 months, c) known previous carriage of CRE in the last 12 months and d) epidemiological linkage to a known carrier of a CRE.Core infection prevention and control measures that should be considered for all patients in healthcare settings were compiled. Preliminary supplemental measures to be implemented for "at-risk" patients on admission are: pre-emptive isolation, active screening for CRE
and contact precautions. Patients who are confirmed positive for CRE will need additional supplemental measures.
Strengthening the microbiological capacity, surveillance and reporting of new cases of CRE in healthcare settings and countries is necessary to monitor the epidemiological situation so that, if necessary, the implemented CRE prevention strategies can be refined in a timely manner. Creating a large communication network to exchange this information would be helpful to understand the extent of the CRE reservoir and to prevent infections in healthcare settings, by applying the principles outlined here.This guidance document offers suggestions for best practices, but is in no way prescriptive for all healthcare settings and all countries. Successful implementation will result if there is local commitment and accountability. The options for intervention can be adopted or adapted to local needs, depending on the availability of financial and structural resources.
Abstract
HD 169142 is an excellent target for investigating signs of planet–disk interaction due to previous evidence of gap structures. We perform
J
-band (∼1.2
μ
m) polarized intensity imaging of ...HD 169142 with VLT/SPHERE. We observe polarized scattered light down to 0.″16 (∼19 au) and find an inner gap with a significantly reduced scattered-light flux. We confirm the previously detected double-ring structure peaking at 0.″18 (∼21 au) and 0.″56 (∼66 au) and marginally detect a faint third gap at 0.″70–0.″73 (∼82–85 au). We explore dust evolution models in a disk perturbed by two giant planets, as well as models with a parameterized dust size distribution. The dust evolution model is able to reproduce the ring locations and gap widths in polarized intensity but fails to reproduce their depths. However, it gives a good match with the ALMA dust continuum image at 1.3 mm. Models with a parameterized dust size distribution better reproduce the gap depth in scattered light, suggesting that dust filtration at the outer edges of the gaps is less effective. The pileup of millimeter grains in a dust trap and the continuous distribution of small grains throughout the gap likely require more efficient dust fragmentation and dust diffusion in the dust trap. Alternatively, turbulence or charging effects might lead to a reservoir of small grains at the surface layer that is not affected by the dust growth and fragmentation cycle dominating the dense disk midplane. The exploration of models shows that extracting planet properties such as mass from observed gap profiles is highly degenerate.
The atomic structures of magnesium silicate melts are key to understanding processes related to the evolution of the Earth’s mantle and represent precursors to the formation of most igneous rocks. ...Magnesium silicate compositions also represent a major component of many glass ceramics, and depending on their composition can span the entire fragility range of glass formation. The silica rich enstatite (MgSiO3) composition is a good glass former, whereas the forsterite (Mg2SiO4) composition is at the limit of glass formation. Here, the structure of MgSiO3 and Mg2SiO4 composition glasses obtained from levitated liquids have been modeled using Reverse Monte Carlo fits to diffraction data and by density functional theory. A ring statistics analysis suggests that the lower glass forming ability of the Mg2SiO4 glass is associated with a topologically ordered and very narrow ring distribution. The MgOx polyhedra have a variety of irregular shapes in MgSiO3 and Mg2SiO4 glasses and a cavity analysis demonstrates that both glasses have almost no free volume due to a large contribution from edge sharing of MgOx-MgOx polyhedra. It is found that while the atomic volume of Mg cations in the glasses increases compared to that of the crystalline phases, the number of Mg-O contacts is reduced, although the effective chemical interaction of Mg2+ remains similar. This unusual structure-property relation of Mg2SiO4 glass demonstrates that by using containerless processing it may be possible to synthesize new families of dense glasses and glass ceramics with zero porosity.
We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave ...observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2 +/- 0.1 fm s(exp -2)/square root of Hz, or (0.54 +/- 0.01) x 10(exp -15) g/square root of Hz, with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8 +/- 0.3) fm square root of Hz, about 2 orders of magnitude better than requirements. At f less than or equal to 0.5 mHz we observe a low-frequency tail that stays below 12 fm s(exp -2)/square root of Hz down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.
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