31 research outputs found
Antegrade anterior column acetabulum fracture fixation with cannulated compression headless screws-A biomechanical study on standardized osteoporotic artificial bone
PURPOSE
Due to the increase in life expectancy and high-energy traumas, anterior column acetabular fractures (ACFs) are also increasing. While open reduction and internal fixation (ORIF) is still the standard surgical procedure, minimally invasive, percutaneous fixation of osteoporotic acetabulum fractures (AF) are growing in popularity. The aim of this biomechanical study was to evaluate the biomechanical competence following antegrade fixation with a standard screw versus a cannulated compression headless screw.
METHODS
Eight anatomical osteoporotic composite pelvises were given an anterior column fracture. Two groups of eight specimens each (n = 8) for fixation with either a 6.5 mm cannulated compression headless screw in group Anterior Acetabulum Canulated Compression Headless Screw (AACCH), or with a 6.5 mm partially threaded cannulated screw in group Anterior Acetabulum Standard Screw (AASS) where compared. Each specimen was biomechanically loaded cyclically at a rate of 2 Hz with monotonically increasing compressive load until failure. Motions were assessed by means of optical motion tracking.
RESULTS
Initial construct stiffness trended higher in group AACCH at 152.4 ± 23.1 N/mm compared to group AASS at 118.5 ± 34.3 N/mm, p = 0.051. Numbers of cycles and corresponding peak load at failure, were significantly higher in group AACCH at 6734 ± 1669 cycles and 873.4 ± 166.9 N versus group AASS at 4440 ± 2063 cycles and 644.0 ± 206.3 N, p = 0.041. Failure modes were breakout of the screws around the proximal entry point.
CONCLUSION
From a biomechanical perspective, group AACCH was associated with superior biomechanical competence compared to standard partially threaded cannulated screws and could therefore be considered as valid alternative for fixation of anterior acetabulum fractures
The TESS Triple-9 Catalog II: a new set of 999 uniformly-vetted exoplanet candidates
The Transiting Exoplanet Survey Satellite (TESS) mission is providing the
scientific community with millions of light curves of stars spread across the
whole sky. Since 2018 the telescope has detected thousands of planet candidates
that need to be meticulously scrutinized before being considered amenable
targets for follow-up programs. We present the second catalog of the Plant
Patrol citizen science project containing 999 uniformly-vetted exoplanet
candidates within the TESS ExoFOP archive. The catalog was produced by fully
exploiting the power of the Citizen Science Planet Patrol project. We vetted
TESS Objects of Interest (TOIs) based on the results of Discovery And Vetting
of Exoplanets DAVE pipeline. We also implemented the Automatic Disposition
Generator, a custom procedure aimed at generating the final classification for
each TOI that was vetted by at least three vetters. The majority of the
candidates in our catalog, TOIs, passed the vetting process and were
labelled as planet candidates. We ruled out candidates as false positives
and flagged as potential false positives. Our final dispositions and
comments for all the planet candidates are provided as a publicly available
supplementary table.Comment: 17 pages, 11 figures, 5 tables. Accepted for publication on MNRA
A systematic validation of hot Neptunes in TESS data
We statistically validated a sample of hot Neptune candidates applying a
two-step vetting technique using DAVE and TRICERATOPS. We performed a
systematic validation of 250 transit-like events in the Transiting Exoplanet
Survey Satellite (TESS) archive in the parameter region defined by d
and . Through our analysis, we identified 18 hot
Neptune-sized candidates, with a false positive probability . Nine of
these planet candidates still need to be confirmed. For each of the nine
targets we retrieved the stellar parameters using ARIADNE and derived
constraints on the planetary parameters by fitting the lightcurves with the
juliet package. Within this sample of nine candidates, we statistically
validated (i.e, with false positive probability < ) two systems (TOI-277
b and TOI-1288 b) by re-processing the candidates with TRICERATOPS along with
follow-up observations. These new validated exoplanets expand the known hot
Neptunes population and are high-priority targets for future radial velocities
follow-up.Comment: 24 pages, 20 figures. Accepted for publication on MNRA
TESS discovery of a super-Earth and two sub-Neptunes orbiting the bright, nearby, Sun-like star HD 22946
We report the Transiting Exoplanet Survey Satellite (TESS) discovery of a
three-planet system around the bright Sun-like star HD~22946(V=8.3 mag),also
known as TIC~100990000, located 63 parsecs away.The system was observed by TESS
in Sectors 3, 4, 30 and 31 and two planet candidates, labelled TESS Objects of
Interest (TOIs) 411.01 (planet ) and 411.02 (planet ), were identified on
orbits of 9.57 and 4.04 days, respectively. In this work, we validate the two
planets and recover an additional single transit-like signal in the light
curve, which suggests the presence of a third transiting planet with a longer
period of about 46 days.We assess the veracity of the TESS transit signals and
use follow-up imaging and time series photometry to rule out false positive
scenarios, including unresolved binary systems, nearby eclipsing binaries or
background/foreground stars contaminating the light curves. Parallax
measurements from Gaia EDR3, together with broad-band photometry and
spectroscopic follow-up by TFOP allowed us to constrain the stellar parameters
of TOI-411, including its radius of. Adopting this value,
we determined the radii for the three exoplanet candidates and found that
planet is a super-Earth, with a radius of , while
planet and are sub-Neptunian planets, with radii
of and respectively. By using
dynamical simulations, we assessed the stability of the system and evaluated
the possibility of the presence of other undetected, non-transiting planets by
investigating its dynamical packing. We find that the system is dynamically
stable and potentially unpacked, with enough space to host at least one more
planet between and .(Abridged)Comment: 21 pages, 12 figures. Accepted for publication on A&
Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19
Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe
Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies
There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity
European Society of Cardiology: Cardiovascular Disease Statistics 2019
Aims The 2019 report from the European Society of Cardiology (ESC) Atlas provides a contemporary analysis of cardiovascular disease (CVD) statistics across 56 member countries, with particular emphasis on international inequalities in disease burden and healthcare delivery together with estimates of progress towards meeting 2025 World Health Organization (WHO) non-communicable disease targets. Methods and results In this report, contemporary CVD statistics are presented for member countries of the ESC. The statistics are drawn from the ESC Atlas which is a repository of CVD data from a variety of sources including the WHO, the Institute for Health Metrics and Evaluation, and the World Bank. The Atlas also includes novel ESC sponsored data on human and capital infrastructure and cardiovascular healthcare delivery obtained by annual survey of the national societies of ESC member countries. Across ESC member countries, the prevalence of obesity (body mass index ≥30 kg/m2) and diabetes has increased two- to three-fold during the last 30 years making the WHO 2025 target to halt rises in these risk factors unlikely to be achieved. More encouraging have been variable declines in hypertension, smoking, and alcohol consumption but on current trends only the reduction in smoking from 28% to 21% during the last 20 years appears sufficient for the WHO target to be achieved. The median age-standardized prevalence of major risk factors was higher in middle-income compared with high-income ESC member countries for hypertension {23.8% [interquartile range (IQR) 22.5–23.1%] vs. 15.7% (IQR 14.5–21.1%)}, diabetes [7.7% (IQR 7.1–10.1%) vs. 5.6% (IQR 4.8–7.0%)], and among males smoking [43.8% (IQR 37.4–48.0%) vs. 26.0% (IQR 20.9–31.7%)] although among females smoking was less common in middle-income countries [8.7% (IQR 3.0–10.8) vs. 16.7% (IQR 13.9–19.7%)]. There were associated inequalities in disease burden with disability-adjusted life years per 100 000 people due to CVD over three times as high in middle-income [7160 (IQR 5655–8115)] compared with high-income [2235 (IQR 1896–3602)] countries. Cardiovascular disease mortality was also higher in middle-income countries where it accounted for a greater proportion of potential years of life lost compared with high-income countries in both females (43% vs. 28%) and males (39% vs. 28%). Despite the inequalities in disease burden across ESC member countries, survey data from the National Cardiac Societies of the ESC showed that middle-income member countries remain severely under-resourced compared with high-income countries in terms of cardiological person-power and technological infrastructure. Under-resourcing in middle-income countries is associated with a severe procedural deficit compared with high-income countries in terms of coronary intervention, device implantation and cardiac surgical procedures. Conclusion A seemingly inexorable rise in the prevalence of obesity and diabetes currently provides the greatest challenge to achieving further reductions in CVD burden across ESC member countries. Additional challenges are provided by inequalities in disease burden that now require intensification of policy initiatives in order to reduce population risk and prioritize cardiovascular healthcare delivery, particularly in the middle-income countries of the ESC where need is greatest
Norwegian population-based study of long-term effects, safety, and predictors of response of vagus nerve stimulation treatment in drug-resistant epilepsy: The NORPulse study
Objective
This study was undertaken to evaluate the efficacy of vagus nerve stimulation (VNS) over time, and to determine which patient groups derive the most benefit.
Methods
Long-term outcomes are reported in 436 epilepsy patients from a VNS quality registry (52.8% adults, 47.2% children), with a median follow-up of 75 months. Patients were stratified according to evolution of response into constant responders, fluctuating responders, and nonresponders. The effect was evaluated at 6, 12, 24, 36, and 60 months. Multivariate regression analysis was used to identify predictors of response.
Results
The cumulative probability of ≥50% seizure reduction was 60%; however, 15% of patients showed a fluctuating course. Of those becoming responders, 89.5% (230/257) did so within 2 years. A steady increase in effect was observed among constant responders, with 48.7% (19/39) of those becoming seizure-free and 29.3% (39/133) with ≥75% seizure reduction achieving these effects within 2–5 years. Some effect (25%–<50%) at 6 months was a positive predictor of becoming a responder (odds ratio [OR] = 10.18, p < .0001) and having ≥75% reduction at 2 years (OR = 3.34, p = .03). Patients without intellectual disability had ORs of 3.34 and 3.11 of having ≥75% reduction at 2 and 5 years, respectively, and an OR of 6.22 of being seizure-free at last observation. Patients with unchanged antiseizure medication over the observation period showed better responder rates at 2 (63.0% vs. 43.1%, p = .002) and 5 years (63.4% vs. 46.3%, p = .031) than patients whose antiseizure medication was modified. Responder rates were higher for posttraumatic (70.6%, p = .048) and poststroke epilepsies (75.0%, p = .05) than other etiologies (46.5%).
Significance
Our data indicate that the effect of VNS increases over time and that there are important clinical decision points at 6 and 24 months for evaluating and adjusting the treatment. There should be better selection of candidates, as certain patient groups and epilepsy etiologies respond more favorably
SYSTEMATIC REVIEW PROTOCOL Open Access
Are population abundances and biomasses of soil invertebrates changed by Bt crops compared with conventional crops? A systematic review protoco
Is augmented femoral lateral plating with helically shaped medial plates biomechanically advantageous over straight medial plates?
BACKGROUND
Dual plating of comminuted distal femoral fractures allows for early patient mobilization. An additional helically shaped medial plate avoids the medial vital structures of the thigh.
AIM
to investigate the biomechanical competence of augmented lateral locking compression plate distal femur (LCP-DF) using an additional straight versus a helically shaped medial LCP of the same length.
METHODS
Ten pairs of human cadaveric femora were instrumented with a lateral anatomical 15-hole LCP-DF. Following, they were pairwise instrumented with either an additional medial straight 14-hole LCP (group1) or a 90°-helical shape LCP (group2). All specimens were biomechanically tested under quasi-static and progressively increasing combined cyclic axial and torsional loading until failure.
RESULTS
Initial interfragmentary axial displacement and flexion under static compression were significantly smaller in group1 (0.11±0.12mm and 0.21±0.10°) versus group2 (0.31±0.14mm and 0.68±0.16°), p≤0.007. Initial varus deformation under static compression remained not significantly different between group1 (0.57±0.23°) and group2 (0.75±0.34°), p=0.085. Flexion movements during dynamic loading were significantly higher for group2 (2.51±0.54°) versus group1 (1.63±1.28°), p=0.015, however, no significant differences were observed in terms of varus, internal rotation, axial and shear displacements between the groups, p≥0.204. Cycles to failure and load at failure were higher in group2 (25172±6376 and 3017N±638N) compared to group1 (22277±4576 and 2728N±458N) with no significant differences between them, p=0.195.
CONCLUSION
From a biomechanical perspective, helical double plating may be considered as useful alternative to straight double plating, demonstrating ameliorated damping capacities during flexion deformation and safer application as the medial neurovascular structures of the thigh are avoided. This article is protected by copyright. All rights reserved