1,836 research outputs found
Treatment of femoral neck fractures in elderly patients over 60 years of age - which is the ideal modality of primary joint replacement?
BACKGROUND: Femoral neck fractures in the elderly are frequent, represent a great health care problem, and have a significant impact on health insurance costs. Reconstruction options using hip arthroplasty include unipolar or bipolar hemiarthroplasty (HA), and total hip arthroplasty (THA). The purpose of this review is to discuss the indications, limitations, and pitfalls of each of these techniques.
METHODS: The Pubmed database was searched for all articles on femoral neck fracture and for the reconstruction options presented in this review using the search terms "femoral neck fracture", "unipolar hemiarthroplasty", "bipolar hemiarthroplasty", and "total hip arthroplasty". In addition, cross-referencing was used to cover articles eventually undetected by the respective search strategies. The resulting articles were then reviewed with regard to the different techniques, outcome and complications of the distinct reconstruction options.
RESULTS: THA yields the best functional results in patients with displaced femoral neck fractures with complication rates comparable to HA. THA is beneficially implanted using an anterior approach exploiting the internervous plane between the tensor fasciae latae and the sartorius muscles allowing for immediate full weight-bearing. Based on our findings, bipolar hemiarthroplasty, similar to unipolar hemiarthroplasty, cannot restorate neither anatomical nor biomechanical features of the hip joint. Therefore, it can only be recommended as a second line of defense-procedure for patients with low functional demands and limited live expectancy.
CONCLUSIONS: THA is the treatment of choice for femoral neck fractures in patients older than 60 years. HA should only be implanted in patients with limited life expectanc
Measuring diet in primary school children aged 8-11 years: validation of the Child and Diet Evaluation Tool (CADET) with an emphasis on fruit and vegetable intake.
Background/Objectives:The Child And Diet Evaluation Tool (CADET) is a 24-h food diary that measures the nutrition intake of children aged 3-7 years, with a focus on fruit and vegetable consumption. Until now CADET has not been used to measure nutrient intake of children aged 8-11 years. To ensure that newly assigned portion sizes for this older age group were valid, participants were asked to complete the CADET diary (the school and home food diary) concurrently with a 1-day weighed record. Subjects/Methods:A total of 67 children with a mean age of 9.3 years (s.d.: Âą 1.4, 51% girls) participated in the study. Total fruit and vegetable intake in grams and other nutrients were extracted to compare the mean intakes from the CADET diary and Weighed record using t-tests and Pearson's r correlations. Bland-Altman analysis was also conducted to assess the agreement between the two methods. Results: Correlations comparing the CADET diary to the weighed record were high for fruit, vegetables and combined fruit and vegetables (r=0.7). The results from the Bland-Altman plots revealed a mean difference of 54âg (95% confidence interval: -88, 152) for combined fruit and vegetables intake. CADET is the only tool recommended by the National Obesity Observatory that has been validated in a UK population and provides nutrient level data on children's diets. Conclusions:The results from this study conclude that CADET can provide high-quality nutrient data suitable for evaluating intervention studies now for children aged 3-11 years with a focus on fruit and vegetable intake
Is the Internal Rotation Lag Sign a Sensitive Test for Detecting Hip Abductor Tendon Ruptures after Total Hip Arthroplasty?
INTRODUCTION: Total hip arthroplasty (THA) is one of the most frequently performed procedures in orthopaedics and weakness of external rotators is often recognized thereafter. However, the etiology of lateral hip pain is multifaceted. For the diagnosis of abductor tendon rupture, magnetic resonance imaging (MRI) is the gold standard. As not every patient can be subjected to MRI, a clinical diagnostic test for easy detection of lesions of the abductor tendon is missing. Here, we present the internal rotation lack sign indicating abductor tendon pathology.
METHODS: The patient is placed in lateral position on a stretcher with hips and knees in neutral position. The knee is flexed to 45° and the hip passively abducted and elevated by the investigator. With the foot passively abducted, the patient is then asked to bring his knee in direction to the examination table. This motion is also tested passively. The test is regarded positive, if no internal rotation is possible and/or if this is painful. If groin pain is elicited during either of the exercises, the test is also rated positive.
RESULTS: We evaluated this test in 20 patients clinically and by magnetic resonance imaging (MRI). All patients demonstrated a positive internal rotation lag sign. Twelve of them lag of internal rotation and evidence of anterior abductor tendon rupture on MRI, 8 with lag of internal rotation and no evidence of abductor tendon rupture.
CONCLUSION: The new clinical diagnostic sign presented here may improve the diagnosis of abductor tendon rupture in the future.Level of Evidence: Diagnostic study, level I
Cryo-EM structure of a helicase loading intermediate containing ORC-Cdc6-Cdt1-MCM2-7 bound to DNA
In eukaryotes, the Cdt1-bound replicative helicase core MCM2-7 is loaded onto DNA by the ORC-Cdc6 ATPase to form a prereplicative complex (pre-RC) with an MCM2-7 double hexamer encircling DNA. Using purified components in the presence of ATP-ÎłS, we have captured in vitro an intermediate in pre-RC assembly that contains a complex between the ORC-Cdc6 and Cdt1-MCM2-7 heteroheptamers called the OCCM. Cryo-EM studies of this 14-subunit complex reveal that the two separate heptameric complexes are engaged extensively, with the ORC-Cdc6 N-terminal AAA+ domains latching onto the C-terminal AAA+ motor domains of the MCM2-7 hexamer. The conformation of ORC-Cdc6 undergoes a concerted change into a right-handed spiral with helical symmetry that is identical to that of the DNA double helix. The resulting ORC-Cdc6 helicase loader shows a notable structural similarity to the replication factor C clamp loader, suggesting a conserved mechanism of action
Election turnout statistics in many countries: similarities, differences, and a diffusive field model for decision-making
We study in details the turnout rate statistics for 77 elections in 11
different countries. We show that the empirical results established in a
previous paper for French elections appear to hold much more generally. We find
in particular that the spatial correlation of turnout rates decay
logarithmically with distance in all cases. This result is quantitatively
reproduced by a decision model that assumes that each voter makes his mind as a
result of three influence terms: one totally idiosyncratic component, one
city-specific term with short-ranged fluctuations in space, and one long-ranged
correlated field which propagates diffusively in space. A detailed analysis
reveals several interesting features: for example, different countries have
different degrees of local heterogeneities and seem to be characterized by a
different propensity for individuals to conform to the cultural norm. We
furthermore find clear signs of herding (i.e. strongly correlated decisions at
the individual level) in some countries, but not in others.Comment: 15 pages, 9 figures, 7 table
Cement-augmented dorsal instrumentation of the spine as a safe adjunct to the multimodal management of metastatic pheochromocytoma: a case report
Malignant pheochromocytoma is a neuroendocrine tumor that originates from chromaffin tissue. Although osseous metastases are common, metastatic dissemination to the spine rarely occurs
Direct Observation of the Superfluid Phase Transition in Ultracold Fermi Gases
Water freezes into ice, atomic spins spontaneously align in a magnet, liquid
helium becomes superfluid: Phase transitions are dramatic phenomena. However,
despite the drastic change in the system's behaviour, observing the transition
can sometimes be subtle. The hallmark of Bose-Einstein condensation (BEC) and
superfluidity in trapped, weakly interacting Bose gases is the sudden
appearance of a dense central core inside a thermal cloud. In strongly
interacting gases, such as the recently observed fermionic superfluids, this
clear separation between the superfluid and the normal parts of the cloud is no
longer given. Condensates of fermion pairs could be detected only using
magnetic field sweeps into the weakly interacting regime. The quantitative
description of these sweeps presents a major theoretical challenge. Here we
demonstrate that the superfluid phase transition can be directly observed by
sudden changes in the shape of the clouds, in complete analogy to the case of
weakly interacting Bose gases. By preparing unequal mixtures of the two spin
components involved in the pairing, we greatly enhance the contrast between the
superfluid core and the normal component. Furthermore, the non-interacting
wings of excess atoms serve as a direct and reliable thermometer. Even in the
normal state, strong interactions significantly deform the density profile of
the majority spin component. We show that it is these interactions which drive
the normal-to-superfluid transition at the critical population imbalance of
70(5)%.Comment: 16 pages (incl. Supplemental Material), 5 figure
Evidence for Anthropogenic Surface Loading as Trigger Mechanism of the 2008 Wenchuan Earthquake
Two and a half years prior to China's M7.9 Wenchuan earthquake of May 2008,
at least 300 million metric tons of water accumulated with additional seasonal
water level changes in the Minjiang River Valley at the eastern margin of the
Longmen Shan. This article shows that static surface loading in the Zipingpu
water reservoir induced Coulomb failure stresses on the nearby Beichuan thrust
fault system at <17km depth. Triggering stresses exceeded levels of daily lunar
and solar tides and perturbed a fault area measuring 416+/-96km^2. These stress
perturbations, in turn, likely advanced the clock of the mainshock and directed
the initial rupture propagation upward towards the reservoir on the
"Coulomb-like" Beichuan fault with rate-and-state dependent frictional
behavior. Static triggering perturbations produced up to 60 years (0.6%) of
equivalent tectonic loading, and show strong correlations to the coseismic
slip. Moreover, correlations between clock advancement and coseismic slip,
observed during the mainshock beneath the reservoir, are strongest for a longer
seismic cycle (10kyr) of M>7 earthquakes. Finally, the daily event rate of the
micro-seismicity (M>0.5) correlates well with the static stress perturbations,
indicating destabilization.Comment: 22 pages, 4 figures, 3 table
Probabilistic inference for determining options in reinforcement learning
Tasks that require many sequential decisions or complex solutions are hard to solve using conventional reinforcement learning algorithms. Based on the semi Markov decision process setting (SMDP) and the option framework, we propose a model which aims to alleviate these concerns. Instead of learning a single monolithic policy, the agent learns a set of simpler sub-policies as well as the initiation and termination probabilities for each of those sub-policies. While existing option learning algorithms frequently require manual specification of components such as the sub-policies, we present an algorithm which infers all relevant components of the option framework from data. Furthermore, the proposed approach is based on parametric option representations and works well in combination with current policy search methods, which are particularly well suited for continuous real-world tasks. We present results on SMDPs with discrete as well as continuous state-action spaces. The results show that the presented algorithm can combine simple sub-policies to solve complex tasks and can improve learning performance on simpler tasks
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