895 research outputs found
Comparative Outcomes of Autologous Chondrocyte Implantation and Osteochondral Allograft Transplantation with Patellar Realignment for Patellar Instability with Associated Cartilage Defects
Abstract Background: Articular cartilage pathology can stem from a spectrum of etiologies including osteochondritis dissecans, avascular necrosis, degenerative joint disease, and injury resulting from recurrent instability of the patella.
Hypothesis/Purpose: The purpose of this study was to identify differences in clinical and functional outcomes in patients treated with either ACI or OCA transplantation for chondral defects with concomitant MPFL reconstruction and tibia tubercle osteotomy.
Study Design: Retrospective Cohort Study
Methods: A retrospective review identified patients who underwent autologous chondrocyte implantation (ACI) or osteochondral allograft (OCA) transplantation with concomitant medial patellofemoral ligament (MPFL) reconstruction and tibia tubercle osteotomy (TTO). Outcome measures included the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR), International Knee Documentation Committee (IKDC) evaluation, and Short Form Health Survey (SF-12) physical scores, all collected a minimum of 2 years after surgery. Defect location, size, complications, and rate of subsequent surgery were determined.
Results: Eighteen patients (11 ACI and 7 OCA) were included in this study to analyze clinical and functional outcomes following surgical correction of 23 chondral defects (ACI n=12, OCA n=10). Defects had comparable baseline characteristics in each group including size measured during index arthroscopy (3.34 cm2 vs 4.03 cm2, P = .351), Outerbridge classification (54.8% grade 4 vs 60.0% grade 4, P = 1.000), and AMADEUS score (47.1 vs 58.6, P = .298). Postoperative outcomes were comparable including revision rate (15.4% vs 10.0%, P=1.000) and 2-year IKDC scores (74.2 vs 51.2, P = .077). However, ACI did have significantly higher 2-year KOOS JR (85.1 vs 63.7, P = .031) and SF-12 scores (54.1 vs 42.6, P = .007) compared to OCA.
Conclusion: ACI or OCA transplantation for chondral defects with concomitant MPFL reconstruction and TTO can be safely performed in an outpatient setting with functional and clinical outcomes being comparable. Functional scores including KOOS JR and SF-12 were shown to be significantly higher at 2-year follow-up in the ACI cohort, however, postoperative IKDC scores, rates of revisions, and clinical evaluations were comparable between cohorts
The GLOBE climate legislation study: a review of climate change legislation in 66 countries: fourth edition
The GLOBE Climate Legislation Study is the most comprehensive audit of climate legislation across 66 countries, together responsible for around 88% of global manmade greenhouse gas emissions. It is produced by the Grantham Research Institute at the London School of Economics in collaboration with GLOBE International. The 4th edition of the Study was formally launched at the 2nd GLOBE Climate Legislation Summit held at the Senate of the United States of America and at the World Bank in Washington DC on 27th-28th February 2014. The next edition of the Climate Legislation Study will be launched in early 2015, covering legislation in 100 countries. Key messages from the 4th edition: ◾Almost 500 climate laws have been passed in the 66 countries covered by the study; the direction of travel is clear; and encouragingly, it is developing countries and emerging markets, which are advancing climate change laws and regulation at the fastest pace. ◾Even though the legislative progress is impressive, the cumulative ambition of these laws is not yet sufficient to limit global average temperature rise to 2 degrees Celsius above pre-industrial levels, the agreed goal of the international community. ◾In order for a successful outcome in Paris in 2015 there is now extreme urgency to strengthen commitments, and for countries that have not yet passed climate change laws and/or regulations to do so
Comparison of prestellar core elongations and large-scale molecular cloud structures in the Lupus 1 region
Turbulence and magnetic fields are expected to be important for regulating molecular cloud formation and evolution. However, their effects on sub-parsec to 100 parsec scales, leading to the formation of starless cores, are not well understood. We investigate the prestellar core structure morphologies obtained from analysis of the Herschel-SPIRE 350 mum maps of the Lupus I cloud. This distribution is first compared on a statistical basis to the large-scale shape of the main filament. We find the distribution of the elongation position angle of the cores to be consistent with a random distribution, which means no specific orientation of the morphology of the cores is observed with respect to the mean orientation of the large-scale filament in Lupus I, nor relative to a large-scale bent filament model. This distribution is also compared to the mean orientation of the large-scale magnetic fields probed at 350 mum with the Balloon-borne Large Aperture Telescope for Polarimetry during its 2010 campaign. Here again we do not find any correlation between the core morphology distribution and the average orientation of the magnetic fields on parsec scales. Our main conclusion is that the local filament dynamics---including secondary filaments that often run orthogonally to the primary filament---and possibly small-scale variations in the local magnetic field direction, could be the dominant factors for explaining the final orientation of each core
The balloon-borne large-aperture submillimeter telescope for polarimetry: BLAST-Pol
The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry
(BLAST-Pol) is a suborbital mapping experiment designed to study the role
played by magnetic fields in the star formation process. BLAST-Pol is the
reconstructed BLAST telescope, with the addition of linear polarization
capability. Using a 1.8 m Cassegrain telescope, BLAST-Pol images the sky onto a
focal plane that consists of 280 bolometric detectors in three arrays,
observing simultaneously at 250, 350, and 500 um. The diffraction-limited
optical system provides a resolution of 30'' at 250 um. The polarimeter
consists of photolithographic polarizing grids mounted in front of each
bolometer/detector array. A rotating 4 K achromatic half-wave plate provides
additional polarization modulation. With its unprecedented mapping speed and
resolution, BLAST-Pol will produce three-color polarization maps for a large
number of molecular clouds. The instrument provides a much needed bridge in
spatial coverage between larger-scale, coarse resolution surveys and narrow
field of view, and high resolution observations of substructure within
molecular cloud cores. The first science flight will be from McMurdo Station,
Antarctica in December 2010.Comment: 14 pages, 9 figures Submitted to SPIE Astronomical Telescopes and
Instrumentation Conference 201
Introducing best practice for reproducibility in government
There is an appetite to improve the reproducibility of quantitative analysis undertaken across government. Our team supports conversion of regular publications into Reproducible Analytical Pipelines (RAP). To achieve this, we developed a roadmap to work with analysts in our organisation and help them transform their pipelines and build their skills.
An audit of the current RAP status of all regular pipelines assisted in resource allocation and planning. The maturity of a RAP is evaluated on 7 criteria required to reach a minimum viable product (MVP) and 7 additional advanced criteria as outlined by the Analysis Function (AF). We use a combination of hands-on pair-coding with analysis teams, regular and ad hoc code reviews, and training sessions to convert existing pipelines into RAPs, while simultaneously upskilling the analysts. We have also developed guidance and training documentation to share internally and externally.
Currently, out of 73 regular publications, 12 have reached the MVP, with an average score of 4.36 out of 7. This scoring is reassessed monthly, allowing us to track the progress in real-time. Self-assessment of technical skills increased by between 43% and 89% and 97% said their understanding of RAP principals improved because of the training and 77% said they are now able to implement best practice into their work. By working with the pipeline owners instead of just refactoring the code directly, we are ensuring business resilience. The in-depth knowledge of the pipeline and skills required to maintain it are present within the analysis team. Publishing our methods, documentation and tools facilitates adoption of RAP for those without a dedicated RAP team.
We are on track to convert all our regular publications into RAPs and move to “RAP by default”, in line with the AF RAP Strategy. This will improve the reproducibility, quality, efficiency, transparency, and trustworthiness of analysis within government. We hope other organisations can learn from our methods
Tensor Graphical Lasso (TeraLasso)
This paper introduces a multi-way tensor generalization of the Bigraphical
Lasso (BiGLasso), which uses a two-way sparse Kronecker-sum multivariate-normal
model for the precision matrix to parsimoniously model conditional dependence
relationships of matrix-variate data based on the Cartesian product of graphs.
We call this generalization the {\bf Te}nsor g{\bf ra}phical Lasso (TeraLasso).
We demonstrate using theory and examples that the TeraLasso model can be
accurately and scalably estimated from very limited data samples of high
dimensional variables with multiway coordinates such as space, time and
replicates. Statistical consistency and statistical rates of convergence are
established for both the BiGLasso and TeraLasso estimators of the precision
matrix and estimators of its support (non-sparsity) set, respectively. We
propose a scalable composite gradient descent algorithm and analyze the
computational convergence rate, showing that the composite gradient descent
algorithm is guaranteed to converge at a geometric rate to the global minimizer
of the TeraLasso objective function. Finally, we illustrate the TeraLasso using
both simulation and experimental data from a meteorological dataset, showing
that we can accurately estimate precision matrices and recover meaningful
conditional dependency graphs from high dimensional complex datasets.Comment: accepted to JRSS-
Strategies to optimize the impact of nutritional surveys and epidemiological studies
The development of nutrition and health guidelines and policies requires reliable scientific information. Unfortunately, theoretical considerations and empirical evidence indicate that a large percentage of science-based claims rely on studies that fail to replicate. The session "Strategies to Optimize the Impact of Nutrition Surveys and Epidemiological Studies" focused on the elements of design, interpretation, and communication of nutritional surveys and epidemiological studies to enhance and encourage the production of reliable, objective evidence for use in developing dietary guidance for the public. The speakers called for more transparency of research, raw data, consistent data-staging techniques, and improved data analysis. New approaches to collecting data are urgently needed to increase the credibility and utility of findings from nutrition epidemiological studies. Such studies are critical for furthering our knowledge and understanding of the effects of diet on health
1-Aminocyclopropane-1-carboxylic acid (ACC) concentration and ACC synthase expression in soybean roots, root tips, and soybean cyst nematode (Heterodera glycines)-infected roots
Colonization of plant roots by root knot and cyst nematodes requires a functional ethylene response pathway. However, ethylene plays many roles in root development and whether its role in nematode colonization is direct or indirect, for example lateral root initiation or root hair growth, is not known. The temporal requirement for ethylene and localized synthesis of ethylene during the life span of soybean cyst nematode (SCN) on soybean roots was further investigated. Although a significant increase in ethylene evolution was not detected from SCN-colonized roots, the concentration of the immediate precursor to ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC), was higher in SCN-colonized root pieces and root tips than in other parts of the root. Moreover, expression analysis of 17 ACC synthase (ACS) genes indicated that a select set of ACS genes is expressed in SCN-colonized root pieces that is clearly different from the set of genes expressed in non-colonized roots or root tips. Semi-quantitative real-time PCR indicated that ACS transcript accumulation correlates with the high concentration of ACC in root tips. In addition, an ACS-like sequence was found in the public SCN nucleotide database. Acquisition of a full-length sequence for this mRNA (accession GQ389647) and alignment with transcripts for other well-characterized ACS proteins indicated that the nematode sequence is missing a key element required for ACS activity and therefore probably is not a functional ACS. Moreover, no significant amount of ACC was found in any growth stage of SCN that was tested
Differences in Clinical and Functional Outcomes Between Osteochondral Allograft Transplantation and Autologous Chondrocyte Implantation for the Treatment of Focal Articular Cartilage Defects
Background: Articular cartilage pathology can result from a spectrum of origins, including trauma, osteochondritis dissecans, avascular necrosis, or degenerative joint disease.
Purpose: To compare the differences in clinical and patient-reported outcomes after autologous chondrocyte implantation (ACI) versus osteochondral allograft transplantation (OCA) in patients with focal articular cartilage defects without underlying bone loss.
Study design: Cohort study; Level of evidence, 3.
Methods: A retrospective review identified patients who underwent ACI or OCA between 2008 and 2016 for isolated grades 3 and 4 articular cartilage defects without underlying bone loss. Outcome measures included the Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR), International Knee Documentation Committee (IKDC) evaluation, and 12-Item Short Form Health Survey-Physical Component (SF-12-P) scores. Defect location, size, complications, and rate of subsequent surgery were determined.
Results: Overall, 148 patients were included: 82 (55%) underwent ACI and 66 (45%) underwent OCA. The mean age at the time of surgery was 31.2 years within the ACI cohort and 37.7 years within the OCA cohort (P \u3c .001); the mean follow-up for both cohorts was 6.7 years (P = .902). Within the ACI group, 28 (34%) patients had multifocal defects, 21 (26%) had defects confined to the femoral condyles, and 33 (40%) had defects in the patellofemoral region. Within the OCA group, 23 (35%) patients had multifocal defects, 30 (46%) had confined femoral condyle lesions, and 13 (20%) had patellofemoral defects. When comparing by lesion location, there were no significant differences in KOOS JR, and IKDC scores between the ACI and OCA cohorts (P \u3c .05). There was, however, a significant difference for SF-12-P scores for FDD trochlear lesions. In both cohorts, traumatic patellofemoral pathology demonstrated lower patient-reported outcomes and higher failure rates than degenerative lesions. The overall rate of failure, defined as graft failure with revision surgery and/or conversion to arthroplasty, was significantly greater in the OCA group (21% vs 4%; P = .002).
Conclusion: Study results indicated that ACI provides similar outcomes to OCA with or without concomitant procedures for the treatment of symptomatic articular cartilage defects in all lesion locations and may have a lower revision rate for multifocal and condylar lesions
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