Knee adduction moments are not increased in obese knee osteoarthritis patients during stair negotiation

Background: Negotiating stairs is an important activity of daily living that is also associated with large loads on the knee joint. In medial compartment knee osteoarthritis, the knee adduction moment during level walking is considered a marker for disease severity. It could be argued that the discriminative capability of this parameter is even better if tested in a strenuous stair negotiation task. Research question: What is the relation with knee osteoarthritis on the knee adduction moment during the stance phase of both stair ascent and descent in patients with and without obesity? Methods: This case control study included 22 lean controls, 16 lean knee osteoarthritis patients, and 14 obese knee osteoarthritis patients. All subjects ascended and descended a two-step staircase at a self-selected, comfortable speed. Three-dimensional motion analysis was performed to evaluate the knee adduction moment during stair negotiation. Results: Obese knee osteoarthritis patients show a prolonged stance time together with a more flattened knee adduction moment curve during stair ascent. Normalized knee adduction moment impulse, as well as the first and second peaks were not different between groups. During stair descent, a similar increase in stance time was found for both osteoarthritis groups. Significance: The absence of a significant effect of groups on the normalized knee adduction moment during stair negotiation may be explained by a lower ambulatory speed in the obese knee osteoarthritis group, that effectively lowers vertical ground reaction force. Decreasing ambulatory speed may be an effective strategy to lower knee adduction moment during stair negotiation

The merit of high-frequency data in portfolio allocation

This paper addresses the open debate about the usefulness of high-frequency (HF) data in large-scale portfolio allocation. Daily covariances are estimated based on HF data of the S&P 500 universe employing a blocked realized kernel estimator. We propose forecasting covariance matrices using a multi-scale spectral decomposition where volatilities, correlation eigenvalues and eigenvectors evolve on different frequencies. In an extensive out-of-sample forecasting study, we show that the proposed approach yields less risky and more diversified portfolio allocations as prevailing methods employing daily data. These performance gains hold over longer horizons than previous studies have shown

Mapping and modelling the geographical distribution and environmental limits of podoconiosis in Ethiopia

BACKGROUND Ethiopia is assumed to have the highest burden of podoconiosis globally, but the geographical distribution and environmental limits and correlates are yet to be fully investigated. In this paper we use data from a nationwide survey to address these issues. METHODOLOGY Our analyses are based on data arising from the integrated mapping of podoconiosis and lymphatic filariasis (LF) conducted in 2013, supplemented by data from an earlier mapping of LF in western Ethiopia in 2008-2010. The integrated mapping used woreda (district) health offices' reports of podoconiosis and LF to guide selection of survey sites. A suite of environmental and climatic data and boosted regression tree (BRT) modelling was used to investigate environmental limits and predict the probability of podoconiosis occurrence. PRINCIPAL FINDINGS Data were available for 141,238 individuals from 1,442 communities in 775 districts from all nine regional states and two city administrations of Ethiopia. In 41.9% of surveyed districts no cases of podoconiosis were identified, with all districts in Affar, Dire Dawa, Somali and Gambella regional states lacking the disease. The disease was most common, with lymphoedema positivity rate exceeding 5%, in the central highlands of Ethiopia, in Amhara, Oromia and Southern Nations, Nationalities and Peoples regional states. BRT modelling indicated that the probability of podoconiosis occurrence increased with increasing altitude, precipitation and silt fraction of soil and decreased with population density and clay content. Based on the BRT model, we estimate that in 2010, 34.9 (95% confidence interval [CI]: 20.2-51.7) million people (i.e. 43.8%; 95% CI: 25.3-64.8% of Ethiopia's national population) lived in areas environmentally suitable for the occurrence of podoconiosis. CONCLUSIONS Podoconiosis is more widespread in Ethiopia than previously estimated, but occurs in distinct geographical regions that are tied to identifiable environmental factors. The resultant maps can be used to guide programme planning and implementation and estimate disease burden in Ethiopia. This work provides a framework with which the geographical limits of podoconiosis could be delineated at a continental scale

The SAFE-trial:Safe surgery for glioblastoma multiforme: Awake craniotomy versus surgery under general anesthesia. Study. protocol for a multicenter prospective randomized controlled trial

Background: Surgery of GBM nowadays is usually performed under general anesthesia (GA) and resections are often not as aggressive as possible, due to the chance of seriously damaging the patient with a rather low life expectancy. A surgical technique optimizing resection of the tumor in eloquent areas but preventing neurological deficits is necessary to improve survival and quality of life in these patients. Awake craniotomy (AC) with the use of cortical and subcortical stimulation has been widely implemented for low-grade glioma resections (LGG), but not yet for GBM. AC has shown to increase resection percentage and preserve quality of life in LGG and could thus be of important value in GBM surgery. Methods/design: This study is a prospective, multicenter, randomized controlled trial (RCT). Consecutive patients with a glioblastoma in or near eloquent areas (Sawaya grading II/III) will be 1:1 randomized to awake craniotomy or craniotomy under general anesthesia. 246 patients will be included in neurosurgical centers in the Netherlands and Belgium. Primary end-points are: 1) Postoperative neurological morbidity and 2) Proportion of patients with gross-total resections. Secondary end-points are: 1) Health-related quality of life; 2) Progression-free survival (PFS); 3) Overall survival (OS) and 4) Frequency and severity of Serious Adverse Effects in each group. Also, a cost-benefit analysis will be performed. All patients will receive standard adjuvant treatment with concomitant chemoradiotherapy. Discussion: This RCT should demonstrate whether AC is superior to craniotomy under GA on neurological morbidity, extent of resection and survival for glioblastoma resections in or near eloquent areas. Trial registration: Clinicaltrials.gov: NCT03861299 Netherlands Trial Register (NTR): NL758

Concern-driven integrated approaches to nanomaterial testing and assessment - report of the NanoSafety Cluster Working Group

Abstract Bringing together topic-related European Union (EU)-funded projects, the so-called "NanoSafety Cluster" aims at identifying key areas for further research on risk assessment procedures for nanomaterials (NM). The outcome of NanoSafety Cluster Working Group 10, this commentary presents a vision for concern-driven integrated approaches for the (eco-)toxicological testing and assessment (IATA) of NM. Such approaches should start out by determining concerns, i.e., specific information needs for a given NM based on realistic exposure scenarios. Recognised concerns can be addressed in a set of tiers using standardised protocols for NM preparation and testing. Tier 1 includes determining physico-chemical properties, non-testing (e.g., structure-activity relationships) and evaluating existing data. In tier 2, a limited set of in vitro and in vivo tests are performed that can either indicate that the risk of the specific concern is sufficiently known or indicate the need for further testing, including details for such testing. Ecotoxicological testing begins with representative test organisms followed by complex test systems. After each tier, it is evaluated whether the information gained permits assessing the safety of the NM so that further testing can be waived. By effectively exploiting all available information, IATA allow accelerating the risk assessment process and reducing testing costs and animal use (in line with the 3Rs principle implemented in EU Directive 2010/63/EU). Combining material properties, exposure, biokinetics and hazard data, information gained with IATA can be used to recognise groups of NM based upon similar modes of action. Grouping of substances in return should form integral part of the IATA themselves

Study of coupling loss on bi-columnar BSCCO/Ag tapes by a.c. susceptibility measurements

Coupling losses were studied in composite tapes containing superconducting material in the form of two separate stacks of densely packed filaments embedded in a metallic matrix of Ag or Ag alloy. This kind of sample geometry is quite favorable for studying the coupling currents and in particular the role of superconducting bridges between filaments. By using a.c. susceptibility technique, the electromagnetic losses as function of a.c. magnetic field amplitude and frequency were measured at the temperature T = 77 K for two tapes with different matrix composition. The length of samples was varied by subsequent cutting in order to investigate its influence on the dynamics of magnetic flux penetration. The geometrical factor $\chi_0$ which takes into account the demagnetizing effects was established from a.c. susceptibility data at low amplitudes. Losses vs frequency dependencies have been found to agree nicely with the theoretical model developed for round multifilamentary wires. Applying this model, the effective resistivity of the matrix was determined for each tape, by using only measured quantities. For the tape with pure silver matrix its value was found to be larger than what predicted by the theory for given metal resistivity and filamentary architecture. On the contrary, in the sample with a Ag/Mg alloy matrix, an effective resistivity much lower than expected was determined. We explain these discrepancies by taking into account the properties of the electrical contact of the interface between the superconducting filaments and the normal matrix. In the case of soft matrix of pure Ag, this is of poor quality, while the properties of alloy matrix seem to provoke an extensive creation of intergrowths which can be actually observed in this kind of samples.Comment: 20 pages 11 figure, submitted to Superconductor Science and Technolog

Estimating the number of cases of podoconiosis in Ethiopia using geostatistical methods

Background: In 2011, the World Health Organization recognized podoconiosis as one of the neglected tropical diseases. Nonetheless, the number of people with podoconiosis and the geographical distribution of the disease is poorly understood. Based on a nationwide mapping survey and geostatistical modelling, we predict the prevalence of podoconiosis and estimate the number of cases across Ethiopia. Methods: We used nationwide data collected in Ethiopia between 2008 and 2013. Data were available for 141,238 individuals from 1,442 villages in 775 districts from all nine regional states and two city administrations. We developed a geostatistical model of podoconiosis prevalence among adults (individuals aged 15 years or above), by combining environmental factors. The number of people with podoconiosis was then estimated using a gridded map of adult population density for 2015. Results: Podoconiosis is endemic in 345 districts in Ethiopia: 144 in Oromia, 128 in Southern Nations, Nationalities and People’s [SNNP], 64 in Amhara, 4 in Benishangul Gumuz, 4 in Tigray and 1 in Somali Regional State. Nationally, our estimates suggest that 1,537,963 adults (95% confidence intervals, 290,923-4,577,031 adults) were living with podoconiosis in 2015. Three regions (SNNP, Oromia and Amhara) contributed 99% of the cases. The highest proportion of individuals with podoconiosis resided in the SNNP (39%), while 32% and 29% of people with podoconiosis resided in Oromia and Amhara Regional States, respectively. Tigray and Benishangul Gumuz Regional States bore lower burdens, and in the remaining regions, podoconiosis was almost non-existent. Discussion: The estimates of podoconiosis cases presented here based upon the combination of currently available epidemiological data and a robust modelling approach clearly show that podoconiosis is highly endemic in Ethiopia. Given the presence of low cost prevention, and morbidity management and disability prevention services, it is our collective responsibility to scale-up interventions rapidly

Individual correlates of podoconiosis in areas of varying endemicity: a case-control study

BACKGROUND Podoconiosis is a non-filarial form of elephantiasis resulting in lymphedema of the lower legs. Previous studies have suggested that podoconiosis arises from the interplay of individual and environmental factors. Here, our aim was to understand the individual-level correlates of podoconiosis by comparing 460 podoconiosis-affected individuals and 707 unaffected controls. METHODS/PRINCIPAL FINDINGS This was a case-control study carried out in six kebeles (the lowest governmental administrative unit) in northern Ethiopia. Each kebele was classified into one of three endemicity levels: 'low' (prevalence 5%). A total of 142 (30.7%) households had two or more cases of podoconiosis. Compared to controls, the majority of the cases, especially women, were less educated (OR = 1.7, 95% CI = 1.3 to 2.2), were unmarried (OR = 3.4, 95% CI = 2.6-4.6) and had lower income (t = -4.4, p<0.0001). On average, cases started wearing shoes ten years later than controls. Among cases, age of first wearing shoes was positively correlated with age of onset of podoconiosis (r = 0.6, t = 12.5, p<0.0001). Among all study participants average duration of shoe wearing was less than 30 years. Between both cases and controls, people in 'high' and 'medium' endemicity kebeles were less likely than people in 'low' endemicity areas to 'ever' have owned shoes (OR = 0.5, 95% CI = 0.4-0.7). CONCLUSIONS Late use of shoes, usually after the onset of podoconiosis, and inequalities in education, income and marriage were found among cases, particularly among females. There were clustering of cases within households, thus interventions against podoconiosis will benefit from household-targeted case tracing. Most importantly, we identified a secular increase in shoe-wearing over recent years, which may give opportunities to promote shoe-wearing without increasing stigma among those at high risk of podoconiosis

The era of reference genomes in conservation genomics

Progress in genome sequencing now enables the large-scale generation of reference genomes. Various international initiatives aim to generate reference genomes representing global biodiversity. These genomes provide unique insights into genomic diversity and architecture, thereby enabling comprehensive analyses of population and functional genomics, and are expected to revolutionize conservation genomics

The limited importance of size-asymmetric light competition and growth of pioneer species in early secondary forest succession in Vietnam

It is generally believed that asymmetric competition for light plays a predominant role in determining the course of succession by increasing size inequalities between plants. Size-related growth is the product of size-related light capture and light-use efficiency (LUE). We have used a canopy model to calculate light capture and photosynthetic rates of pioneer species in sequential vegetation stages of a young secondary forest stand. Growth of the same saplings was followed in time as succession proceeded. Photosynthetic rate per unit plant mass (Pmass: mol C g−1 day−1), a proxy for plant growth, was calculated as the product of light capture efficiency [Φmass: mol photosynthetic photon flux density (PPFD) g−1 day−1] and LUE (mol C mol PPFD−1). Species showed different morphologies and photosynthetic characteristics, but their light-capturing and light-use efficiencies, and thus Pmass, did not differ much. This was also observed in the field: plant growth was not size-asymmetric. The size hierarchy that was present from the very early beginning of succession remained for at least the first 5 years. We conclude, therefore, that in slow-growing regenerating vegetation stands, the importance of asymmetric competition for light and growth can be much less than is often assumed