312 research outputs found
Human knee joint finite element model using a two bundle anterior cruciate ligament: Validation and gait analysis
Anterior cruciate ligament (ACL) deficient individuals are at a much higher risk of developing osteoarthritis (OA) compared to those with intact ACLs, likely due to altered biomechanical loading [1]. Research indicates the ACL is comprised of two “bundles”, the anteromedial (AM) and posterolateral (PL) bundles [2]. Although the function of both bundles is to restrain anterior tibial translation (ATT), each bundle has their own distinct range of knee flexion where they are most effective [3].
Articular cartilage contact stress measurements are difficult to measure in vivo. An alternative approach is to use knee joint finite element models (FEMs) to predict soft tissue stresses and strains throughout the knee. Initial and boundary conditions for these FEMs may be determined from knee joint kinematics estimated from motion analysis experiments. However, there is a lack of knee joint FEMs which include both AM and PL bundles to predict changes to articular cartilage contact pressures resulting from ACL injuries. The purpose of this study is to develop and validate a knee joint FEM using both AM and PL bundles and subsequently perform a gait analysis of varying ACL injuries
Using OpenSim to predict knee joint moments during cycling
Cycling is a relatively low impact activity conventionally recommended as a rehabilitative or fitness sustaining exercise for patients at a high risk for knee osteoarthritis (OA) [1,2]. Expanding our understanding of knee joint loads is necessary to develop and improve evidence-based prescriptions for cycling as a rehabilitative and fitness therapy that limits the risk for knee OA.
OpenSim (www.simtk.org) is an open source biomechanical analysis software that can partition predictions of external joint loads (or net muscle moments) into muscle and joint contact loads [3]. Joint contact loads more accurately represent cartilage tissue loading and hence risk for cartilage damage and/or OA [4]. As a first step towards predicting knee joint contact loads during cycling, we hypothesized that OpenSim can predict external knee joint moments that are consistent with published data [5,6]. To address this hypothesis, we conducted cycling experiments and used OpenSim’s scale tool, inverse kinematics (IK) solver, and inverse dynamics (ID) solver to model the recorded activity
Identifying molecular mediators of the relationship between body mass index and endometrial cancer risk:a Mendelian randomization analysis
Endometrial cancer is the most common gynaecological cancer in high-income countries. Elevated body mass index (BMI) is an established modifiable risk factor for this condition and is estimated to confer a larger effect on endometrial cancer risk than any other cancer site. However, the molecular mechanisms underpinning this association remain unclear. We used Mendelian randomization (MR) to evaluate the causal role of 14 molecular risk factors (hormonal, metabolic and inflammatory markers) in endometrial cancer risk. We then evaluated and quantified the potential mediating role of these molecular traits in the relationship between BMI and endometrial cancer using multivariable MR.
Methods
Genetic instruments to proxy 14 molecular risk factors and BMI were constructed by identifying single-nucleotide polymorphisms (SNPs) reliably associated (P < 5.0 × 10−8) with each respective risk factor in previous genome-wide association studies (GWAS). Summary statistics for the association of these SNPs with overall and subtype-specific endometrial cancer risk (12,906 cases and 108,979 controls) were obtained from a GWAS meta-analysis of the Endometrial Cancer Association Consortium (ECAC), Epidemiology of Endometrial Cancer Consortium (E2C2) and UK Biobank. SNPs were combined into multi-allelic models and odds ratios (ORs) and 95% confidence intervals (95% CIs) were generated using inverse-variance weighted random-effects models. The mediating roles of the molecular risk factors in the relationship between BMI and endometrial cancer were then estimated using multivariable MR
ML-based Real-Time Control at the Edge: An Approach Using hls4ml
This study focuses on implementing a real-time control system for a particle
accelerator facility that performs high energy physics experiments. A critical
operating parameter in this facility is beam loss, which is the fraction of
particles deviating from the accelerated proton beam into a cascade of
secondary particles. Accelerators employ a large number of sensors to monitor
beam loss. The data from these sensors is monitored by human operators who
predict the relative contribution of different sub-systems to the beam loss.
Using this information, they engage control interventions. In this paper, we
present a controller to track this phenomenon in real-time using edge-Machine
Learning (ML) and support control with low latency and high accuracy. We
implemented this system on an Intel Arria 10 SoC. Optimizations at the
algorithm, high-level synthesis, and interface levels to improve latency and
resource usage are presented. Our design implements a neural network, which can
predict the main source of beam loss (between two possible causes) at speeds up
to 575 frames per second (fps) (average latency of 1.74 ms). The practical
deployed system is required to operate at 320 fps, with a 3ms latency
requirement, which has been met by our design successfully
The structural properties of sexual fantasies for sexual offenders : a preliminary model
While the phenomenon of sexual fantasy has been researched extensively, little contemporary inquiry has investigated the structural properties of sexual fantasy within the context of sexual offending. In this study, a qualitative analysis was used to develop a descriptive model of the phenomena of sexual fantasy during the offence process. Twenty-four adult males convicted of sexual offences provided detailed retrospective descriptions of their thoughts, emotions and behaviours—before, during and after their offences. A data-driven approach to model development, known as Grounded Theory, was undertaken to analyse the interview transcripts. A model was developed to elucidate the structural properties of sexual fantasy in the process of sexual offending, as well as the physiological and psychological variables associated with it. The Sexual Fantasy Structural Properties Model (SFSPM) comprises eight categories that describe various properties of sexual fantasy across the offence process. These categories are: origin, context, trigger, perceptual modality, clarity, motion, intensity and emotion. The strengths of the SFSPM are discussed and its clinical implications are reviewed. Finally, the limitations of the study are presented and future research directions discussed
Hypermethioninaemia due to methionine adenosyltransferase I/III (MAT I/III) deficiency: diagnosis in an expanded neonatal screening programme
The Expanded Newborn Screening Program (MS/MS) in the region of Galicia (NW Spain) was initiated in 2000 and includes the measurement of methionine levels in dried blood spots. Between June 2000 and June 2007, 140 818 newborns were analysed, and six cases of persistent hypermethioninaemia were detected: one homocystinuria due to cystathionine β-synthase (CβS) deficiency, and five methionine adenosyltransferase I/III (MAT I/III) deficiencies. The five cases of MAT I/III deficiency represent an incidence of 1/28 163 newborns. In these five patients, methionine levels in dried blood spots ranged from 50 to 147 μmol/L. At confirmation of the persistence of the hypermethioninaemia in a subsequent plasma sample, plasma methionine concentrations were moderately elevated in 4 of the 5 patients (mean 256 μmol/L), while total homocysteine (tHcy) was normal; the remaining patient showed plasma methionine of 573 μmol/L and tHcy of 22.8 μmol/L. All five patients were heterozygous for the same dominant mutation, R264H in the MAT1A gene. With a diet not exceeding recommended protein requirements for their age, all patients maintained methionine levels below 300 μmol/L. Currently, with a mean of 2.5 years since diagnosis, the patients are asymptomatic and show developmental quotients within the normal range. Our results show a rather high frequency of hypermethioninaemia due to MAT I/III deficiency in the Galician neonatal population, indicating a need for further studies to evaluate the impact of persistent isolated hypermethioninaemia in neonatal screening programmes
Studies on the production of branched-chain alcohols in engineered Ralstonia eutropha
Wild-type Ralstonia eutropha H16 produces polyhydroxybutyrate (PHB) as an intracellular carbon storage material during nutrient stress in the presence of excess carbon. In this study, the excess carbon was redirected in engineered strains from PHB storage to the production of isobutanol and 3-methyl-1-butanol (branched-chain higher alcohols). These branched-chain higher alcohols can directly substitute for fossil-based fuels and be employed within the current infrastructure. Various mutant strains of R. eutropha with isobutyraldehyde dehydrogenase activity, in combination with the overexpression of plasmid-borne, native branched-chain amino acid biosynthesis pathway genes and the overexpression of heterologous ketoisovalerate decarboxylase gene, were employed for the biosynthesis of isobutanol and 3-methyl-1-butanol. Production of these branched-chain alcohols was initiated during nitrogen or phosphorus limitation in the engineered R. eutropha. One mutant strain not only produced over 180 mg/L branched-chain alcohols in flask culture, but also was significantly more tolerant of isobutanol toxicity than wild-type R. eutropha. After the elimination of genes encoding three potential carbon sinks (ilvE, bkdAB, and aceE), the production titer improved to 270 mg/L isobutanol and 40 mg/L 3-methyl-1-butanol. Semicontinuous flask cultivation was utilized to minimize the toxicity caused by isobutanol while supplying cells with sufficient nutrients. Under this semicontinuous flask cultivation, the R. eutropha mutant grew and produced more than 14 g/L branched-chain alcohols over the duration of 50 days. These results demonstrate that R. eutropha carbon flux can be redirected from PHB to branched-chain alcohols and that engineered R. eutropha can be cultivated over prolonged periods of time for product biosynthesis.United States. Dept. of EnergyUnited States. Advanced Research Projects Agency-Energ
An ultra-deep sequencing strategy to detect sub-clonal TP53 mutations in presentation chronic lymphocytic leukemia cases using multiple polymerases
Chronic lymphocytic leukaemia (CLL) is the most common clonal B-cell disorder characterized by clonal diversity, a relapsing and remitting course, and in its aggressive forms remains largely incurable. Current front-line regimes include agents such as fludarabine, which act primarily via the DNA damage response pathway. Key to this is the transcription factor p53. Mutations in the TP53 gene, altering p53 functionality, are associated with genetic instability, and are present in aggressive CLL. Furthermore, the emergence of clonal TP53 mutations in relapsed CLL, refractory to DNA-damaging therapy, suggests that accurate detection of sub-clonal TP53 mutations prior to and during treatment may be indicative of early relapse. In this study, we describe a novel deep sequencing workflow using multiple polymerases to generate sequencing libraries (MuPol-Seq), facilitating accurate detection of TP53 mutations at a frequency as low as 0.3%, in presentation CLL cases tested. As these mutations were mostly clustered within the regions of TP53 encoding DNA-binding domains, essential for DNA contact and structural architecture, they are likely to be of prognostic relevance in disease progression. The workflow described here has the potential to be implemented routinely to identify rare mutations across a range of diseases
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