376 research outputs found

    The Utilization of Osteoarticular Transfer System in the Treatment of Distal Femur Osteoid Osteoma: A Case Report

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    We describe a technique for excision of subchondral epiphyseal bone lesions in the distal femur in skeletally immature patients that mitigates risk of complications associated with physeal injury, incomplete tumor resection, and iatrogenic injury to the overlying cartilage

    A Framework Combining Delta Event-Related Oscillations (EROs) and Synchronisation Effects (ERD/ERS) to Study Emotional Processing

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    Event-Related Potentials (ERPs) or Event-Related Oscillations (EROs) have been widely used to study emotional processing, mainly on the theta and gamma frequency bands. However, the role of the slow (delta) waves has been largely ignored. The aim of this study is to provide a framework that combines EROs with Event-Related Desynchronization (ERD)/Event-Related Synchronization (ERS), and peak amplitude analysis of delta activity, evoked by the passive viewing of emotionally evocative pictures. Results showed that this kind of approach is sensitive to the effects of gender, valence, and arousal, as well as, the study of interhemispherical disparity, as the two-brain hemispheres interplay roles in the detailed discrimination of gender. Valence effects are recovered in both the central electrodes as well as in the hemisphere interactions. These findings suggest that the temporal patterns of delta activity and the alterations of delta energy may contribute to the study of emotional processing. Finally the results depict the improved sensitivity of the proposed framework in comparison to the traditional ERP techniques, thereby delineating the need for further development of new methodologies to study slow brain frequencies

    Comparison of Estimated Glomerular Filtration Rate Using Five Equations to Predict Acute Kidney Injury Following Hip Fracture Surgery

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    Introduction: Hip fractures are a common injury and a source of disability and mortality in the aging population. Acute kidney injury (AKI) is a common and potentially serious complication following hip fracture surgery. Estimated glomerular filtration rate (eGFR) is used as an indicator of renal function. Several equations are commonly used to calculate eGFR. The purpose of this study was 1) to evaluate the agreement between five equations in calculating eGFR, and 2) to confirm which equation can best predict AKI in patients undergoing hip fracture surgery. Methods: 146,702 cases of surgical stabilization of hip fracture were queried from the National Surgical Quality Improvement Program (NSQIP) from 2012 to 2019. Preoperative eGFR was calculated using the Cockcroft-Gault, Modification of Diet in Renal Disease (MDRD) II, re-expressed MDRD II, Chronic Kidney Disease Epidemiology Collaboration, and Mayo quadratic (Mayo) equations. The primary outcome measure was AKI. Cases were stratified into two cohorts based on the development of postoperative AKI. These cohorts were compared based on demographic and preoperative factors. Multivariate regression analysis was used to evaluate independent associations between preoperative eGFR and postoperative renal outcomes. Results: Six hundred ninety-nine (0.73%) patients acquired AKI after hip fracture surgery. The Mayo equation yielded the highest mean eGFR (83.8 ± 23.6), while the Re-expressed MDRD II equation yielded the lowest mean eGFR (68.3 ± 35.6). Multivariate regression analysis showed that a decrease in preoperative eGFR was independently associated with an increased risk of postoperative AKI in all five equations. The Akaike information criterion (AIC) was the lowest in the Mayo equation (5116). Conclusions: Preoperative decrease in eGFR in all five equations was independently associated with increased risk of postoperative AKI. The Mayo equation had the highest predictive ability of acquiring postoperative AKI following hip fracture surgery

    Alcohol Affects the Brain's Resting-State Network in Social Drinkers

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    Acute alcohol intake is known to enhance inhibition through facilitation of GABAA receptors, which are present in 40% of the synapses all over the brain. Evidence suggests that enhanced GABAergic transmission leads to increased large-scale brain connectivity. Our hypothesis is that acute alcohol intake would increase the functional connectivity of the human brain resting-state network (RSN). To test our hypothesis, electroencephalographic (EEG) measurements were recorded from healthy social drinkers at rest, during eyes-open and eyes-closed sessions, after administering to them an alcoholic beverage or placebo respectively. Salivary alcohol and cortisol served to measure the inebriation and stress levels. By calculating Magnitude Square Coherence (MSC) on standardized Low Resolution Electromagnetic Tomography (sLORETA) solutions, we formed cortical networks over several frequency bands, which were then analyzed in the context of functional connectivity and graph theory. MSC was increased (p<0.05, corrected with False Discovery Rate, FDR corrected) in alpha, beta (eyes-open) and theta bands (eyes-closed) following acute alcohol intake. Graph parameters were accordingly altered in these bands quantifying the effect of alcohol on the structure of brain networks; global efficiency and density were higher and path length was lower during alcohol (vs. placebo, p<0.05). Salivary alcohol concentration was positively correlated with the density of the network in beta band. The degree of specific nodes was elevated following alcohol (vs. placebo). Our findings support the hypothesis that short-term inebriation considerably increases large-scale connectivity in the RSN. The increased baseline functional connectivity can -at least partially- be attributed to the alcohol-induced disruption of the delicate balance between inhibitory and excitatory neurotransmission in favor of inhibitory influences. Thus, it is suggested that short-term inebriation is associated, as expected, to increased GABA transmission and functional connectivity, while long-term alcohol consumption may be linked to exactly the opposite effect

    Mapping the Spatiotemporal Evolution of Emotional Processing: An MEG Study Across Arousal and Valence Dimensions

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    Electrophysiological and functional neuroimaging findings indicate that the neural mechanisms underlying the processing of emotional dimensions (i.e., valence, arousal) constitute a spatially and temporally distributed emotional network, modulated by the arousal and/or valence of the emotional stimuli. We examined the time course and source distribution of gamma time-locked magnetoencephalographic activity in response to a series of emotional stimuli viewed by healthy adults. We used a beamformer and a sliding window analysis to generate a succession of spatial maps of event-related brain responses across distinct levels of valence (pleasant/unpleasant) and arousal (high/low) in 30–100 Hz. Our results show parallel emotion-related responses along specific temporal windows involving mainly dissociable neural pathways for valence and arousal during emotional picture processing. Pleasant valence was localized in the left inferior frontal gyrus, while unpleasant valence in the right occipital gyrus, the precuneus, and the left caudate nucleus. High arousal was processed by the left orbitofrontal cortex, amygdala, and inferior frontal gyrus, as well as the right middle temporal gyrus, inferior parietal lobule, and occipital gyrus. Pleasant by high arousal interaction was localized in the left inferior and superior frontal gyrus, as well as the right caudate nucleus, putamen, and gyrus rectus. Unpleasant by high arousal interaction was processed by the right superior parietal gyrus. Valence was prioritized (onset at ∼60 ms) to all other effects, while pleasant valence was short lived in comparison to unpleasant valence (offsets at ∼110 and ∼320 ms, respectively). Both arousal and valence × arousal interactions emerged relatively early (onset at ∼150 ms, and ∼170 ms, respectively). Our findings support the notion that brain regions differentiate between valence and arousal, and demonstrate, for the first time, that these brain regions may also respond to distinct combinations of these two dimensions within specific time windows

    Predictors of Hospice Discharge Following Surgical Fixation of Hip Fracture

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    Introduction: Each year, over 300,000 people over the age of 65 are hospitalized for hip fractures, and even with co-management of patients perioperatively with a geriatric team, hip fractures in the elderly are associated with significant morbidity and mortality. Given the extreme morbidity and mortality faced by elderly patients in the post-injury period, recommendations have been put forth for the integration of palliative and even hospice care, to help improve patients’ quality of life. Our objectives were to 1) determine the proportion of patients discharged to hospice following hip fracture surgery and their 30-day mortality rates of these patients, and 2) identify the independent predictors of discharge to hospice. Methods: We retrospectively queried the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) for all hip fractures surgeries between the years of 2016 and 2018. Included cases were stratified into two cohorts: cases involving a discharge to hospice and non-hospice discharge. Variables assessed included patient demographics, comorbidities, perioperative characteristics, and postoperative outcomes. Differences between hospice and non-hospice patients were compared using chi-squared analysis or Fisher\u27s exact test for categorical variables and Student’s t-tests for continuous variables. A binary logistic regression model was used to assess independent predictors of hospice discharge with 30-day mortality. Results: Overall, 31,531 operatively treated hip fractures were identified, of which 281 (0.9%) involved a discharge to hospice. Patients discharged to hospice had a 67% 30-day mortality rate in comparison to 5.6% of patients not discharged to hospice (p \u3c 0.001). Disseminated cancer, dependent functional status, \u3e10% weight loss over six months preoperatively, and preoperative cognitive deficit were the strongest predictors of hospice discharge with 30-day mortality following hip fracture surgery. Conclusions: Current hospice utilization in hip fracture patients remains low, but 30-day mortality in these patients is high. An awareness of the associations between patient characteristics and discharge to hospice with 30-day mortality is important for surgeons to consider when discussing postoperative expectations and outcomes with these patients

    Performance of the LHCb Vertex Detector Alignment Algorithm determined with Beam Test Data

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    LHCb is the dedicated heavy flavour experiment at the Large Hadron Collider at CERN. The partially assembled silicon vertex locator (VELO) of the LHCb experiment has been tested in a beam test. The data from this beam test have been used to determine the performance of the VELO alignment algorithm. The relative alignment of the two silicon sensors in a module and the relative alignment of the modules has been extracted. This alignment is shown to be accurate at a level of approximately 2 micron and 0.1 mrad for translations and rotations, respectively in the plane of the sensors. A single hit precision at normal track incidence of about 10 micron is obtained for the sensors. The alignment of the system is shown to be stable at better than the 10 micron level under air to vacuum pressure changes and mechanical movements of the assembled system.Comment: accepted for publication in NIM

    Performance of the LHCb vertex locator

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    The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated in vacuum, uses a bi-phase CO2 cooling system, and the sensors are moved to 7 mm from the LHC beam for physics data taking. The performance and stability of these characteristic features of the detector are described, and details of the material budget are given. The calibration of the timing and the data processing algorithms that are implemented in FPGAs are described. The system performance is fully characterised. The sensors have a signal to noise ratio of approximately 20 and a best hit resolution of 4 μm is achieved at the optimal track angle. The typical detector occupancy for minimum bias events in standard operating conditions in 2011 is around 0.5%, and the detector has less than 1% of faulty strips. The proximity of the detector to the beam means that the inner regions of the n+-on-n sensors have undergone space-charge sign inversion due to radiation damage. The VELO performance parameters that drive the experiment's physics sensitivity are also given. The track finding efficiency of the VELO is typically above 98% and the modules have been aligned to a precision of 1 μm for translations in the plane transverse to the beam. A primary vertex resolution of 13 μm in the transverse plane and 71 μm along the beam axis is achieved for vertices with 25 tracks. An impact parameter resolution of less than 35 μm is achieved for particles with transverse momentum greater than 1 GeV/c

    Precision luminosity measurements at LHCb

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    Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy √s. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for √s = 2.76, 7 and 8 TeV (proton-proton collisions) and for √sNN = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves significantly the consistency of the results. For proton-proton interactions at √s = 8 TeV a relative precision of the luminosity calibration of 1.47% is obtained using van der Meer scans and 1.43% using beam-gas imaging, resulting in a combined precision of 1.12%. Applying the calibration to the full data set determines the luminosity with a precision of 1.16%. This represents the most precise luminosity measurement achieved so far at a bunched-beam hadron collider
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