Prognostic factors for progression of clinical osteoarthritis of the knee: A systematic review of observational studies

Introduction: We performed a systematic review of prognostic factors for the progression of symptomatic knee osteoarthritis (OA), defined as increase in pain, decline in physical function or total joint replacement. Method: We searched for avail

What Are the Prognostic Factors for Radiographic Progression of Knee Osteoarthritis? A Meta-analysis

Background: A previous systematic review on prognostic factors for knee osteoarthritis (OA) progression showed associations for generalized OA and hyaluronic acid levels. Knee pain, radiographic severity, sex, quadriceps streng

An analysis of distributed solar fuel systems

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 85-89).While solar fuel systems offer tremendous potential to address global clean energy needs, most existing analyses have focused on the feasibility of large centralized systems and applications. Not much research exists on the feasibility of distributed solar fuel systems. This thesis is an attempt to understand the larger context of solar fuel systems, to examine the case for going distributed and to critically analyze a distributed solar fuel system available today in the context of a specific application. In doing so, this thesis seeks to a) provide a baseline analysis for the economic feasibility of a distributed solar fuel system based on state-of-the-art technology b) draw some general conclusions about the nature of such systems in order to provide guidance to those engaged in the development of the next generation of solar fuel systems. This study also compares the chosen baseline solar fuel system with a traditional fossil fuel-based alternative and undertakes a cost-to-emissions trade-off analysis. A key finding of this thesis is that for solar fuel systems to be viable, cost and efficiency improvements in individual sub-systems won't be sufficient. Due attention needs to be given to bring down cost of the entire system. Another key finding is that if carbon emissions are considered as a decision-making criterion in addition to cost, even at current cost levels photovoltaic hydrogen systems compare favorably with existing fossil fuel-based alternatives such as diesel generators.by Alex Thomas.S.M.in Engineering and Managemen

Demystifying normalized difference vegetation index (NDVI) for greenness exposure assessments and policy interventions in urban greening

Most nature and health research use the normalized difference vegetation index (NDVI) for measuring greenness exposure. However, little is known about what NDVI measures in terms of vegetation types (e.g., canopy, grass coverage) within certain analysis zones (e.g., 500 m buffer). Additionally, exploration is needed to understand how to interpret changes in average NDVI (e.g., per 0.1 increments) exposure in relation to changes in vegetation amount and types. In this study, we aimed to explore what vegetation types and amounts best explain the average NDVI and how changes in average NDVI values indicate changes in different vegetation coverages. We used spatial modeling to sample mean NDVI and percentages of vegetation for sample locations within the Greater Manchester case study area. We fitted linear, nonlinear, and mixed multivariate and univariate generalized additive models (GAMs) for multiple spatial scales to identify the relationships between NDVI and vegetation amount and types. Our results showed that the relationships between NDVI and individual vegetation types mostly follow nonlinear trends. We found that canopy and shrubs coverage exhibited a greater influence on mean NDVI exposure values than grass coverage at 300 and 500 m indicating that NDVI values are sensitive to certain types and amounts of vegetation within various buffer zones. We also identified increment in mean NDVI exposure values at lower, mid, and high ranges might be associated with varying changes in total greenspace percentage and individual vegetation types. For instance, at 300 m buffer, an increment of mean NDVI in the lower range (e.g., from 0.2 to 0.3) is associated with an about 17% increase in greenspace percentage. Overall, interpreting changes in NDVI values for urban greening interventions would require careful evaluation of the relative changes in types and quantities of vegetation for different buffer zones

A unique bacteriohopanetetrol stereoisomer of marine anammox

Anaerobic ammonium oxidation (anammox) is a major process of bioavailable nitrogen removal from marine systems. Previously, a bacteriohopanetetrol (BHT) isomer, with unknown stereochemistry, eluting later than BHT using high performance liquid chromatography (HPLC), was detected in ‘Ca. Scalindua profunda’ and proposed as a biomarker for anammox in marine paleo-environments. However, the utility of this BHT isomer as an anammox biomarker is hindered by the fact that four other, non-anammox bacteria are also known to produce a late-eluting BHT stereoisomer. The stereochemistry in Acetobacter pasteurianus, Komagataeibacter xylinus and Frankia sp. was known to be 17β, 21β(H), 22R, 32R, 33R, 34R (BHT-34R). The stereochemistry of the late-eluting BHT in Methylocella palustris was unknown. To determine if marine anammox bacteria produce a unique BHT isomer, we studied the BHT distributions and stereochemistry of known BHT isomer producers and of previously unscreened marine (‘Ca. Scalindua brodeae’) and freshwater (‘Ca. Brocadia sp.’) anammox bacteria using HPLC and gas chromatographic (GC) analysis of acetylated BHTs and ultra high performance liquid chromatography (UHPLC)-high resolution mass spectrometry (HRMS) analysis of non-acetylated BHTs. The 34R stereochemistry was confirmed for the BHT isomers in Ca. Brocadia sp. and Methylocella palustris. However, ‘Ca. Scalindua sp.’ synthesise a stereochemically distinct BHT isomer, with still unconfirmed stereochemistry (BHT-x). Only GC analysis of acetylated BHT and UHPLC analysis of non-acetylated BHT distinguished between late-eluting BHT isomers. Acetylated BHT-x and BHT-34R co-elute by HPLC. As BHT-x is currently only known to be produced by ‘Ca. Scalindua spp.’, it may be a biomarker for marine anammox

Defining hip pain trajectories in early symptomatic hip osteoarthritis - 5 year results from a nationwide prospective cohort study (CHECK)

Objective: To define distinct hip pain trajectories in individuals with early symptomatic hip osteoarthritis (OA) and to determine risk factors for these pain trajectories. Method: Data were obtained from the nationwide prospective Cohort Hip and Cohort Knee (CHECK) study. Participants with hip pain or stiffness and a completed 5-year follow-up were included. Baseline demographic, anamnestic, physical examination characteristics were assessed. Outcome was annually assessed by the Numeric Rating Scale (NRS) for pain. Pain trajectories were retrieved by latent class growth analysis (LCGA). Multinomial logistic regression was used to calculate risk ratios. Results: 545 participants were included. Four distinct pain trajectories were uncovered by LCGA. We found significant differences in baseline characteristics, including body mass index (BMI); symptom severity; pain coping strategies and in criteria for clinical hip OA (American College of Rheumatology (ACR)). Lower education, higher activity limitation scores, frequent use of pain transformation as coping strategy and painful internal hip rotation were more often associated with trajectories characterized by more severe pain. No association was found for baseline radiographic features. Conclusion: We defined four distinct pain trajectories over 5 years follow-up in individuals with early symptomatic hip OA, suggesting there are differences in symptomatic progression of hip OA. Baseline radiographic severity was not associated with the pain trajectories. Future research should be aimed at measuring symptomatic progression of hip OA with even more frequent symptom assessment

A Novel Self-aligned and Maskless Process for Formation of Highly Uniform Arrays of Nanoholes and Nanopillars

Fabrication of a large area of periodic structures with deep sub-wavelength features is required in many applications such as solar cells, photonic crystals, and artificial kidneys. We present a low-cost and high-throughput process for realization of 2D arrays of deep sub-wavelength features using a self-assembled monolayer of hexagonally close packed (HCP) silica and polystyrene microspheres. This method utilizes the microspheres as super-lenses to fabricate nanohole and pillar arrays over large areas on conventional positive and negative photoresist, and with a high aspect ratio. The period and diameter of the holes and pillars formed with this technique can be controlled precisely and independently. We demonstrate that the method can produce HCP arrays of hole of sub-250 nm size using a conventional photolithography system with a broadband UV source centered at 400 nm. We also present our 3D FDTD modeling, which shows a good agreement with the experimental results

The shufflon of IncI1 plasmids is rearranged constantly during different growth conditions

One of the factors that can affect conjugation of IncI1 plasmids, amongst others, is the genetic region known as the shufflon. This multiple inversion system modifies the pilus tip proteins used during conjugation, thus affecting the affinity for different recipient cells. Although recombination is known to occur in in vitro conditions, little is known about the regulation and the extent of recombination that occurs. To measure the recombination of the shufflon, we have amplified the entire shufflon region and sequenced the amplicons using nanopore long-read sequencing. This method was effective to determine the order of the segments of the shufflon and allow for the analysis of the shufflon variants that are present in a heterogeneous pool of templates. Analysis was performed over different growth phases and after addition of cefotaxime. Furthermore, analysis was performed in different E. coli host cells to determine if recombination is likely to be influenced. Recombination of the shufflon was constantly ongoing in all conditions that were measured, although no differences in the amount of different shufflon variants or the rate at which novel variants were formed could be found. As previously reported, some variants were abundant in the population while others were scarce. This leads to the conclusion that the shufflon is continuously recombining at a constant rate, or that the method used here was not sensitive enough to detect differences in this rate. For one of the plasmids, the host cell appeared to have an effect on the specific shufflon variants that were formed which were not predominant in another host, indicating that host factors may be involved. As previously reported, the pilV-A and pilV-A' ORFs are formed at higher frequencies than other pilV ORFs. These results demonstrate that the recombination that occurs within the shufflon is not random. While any regulation of the shufflon affected by these in vitro conditions could not be revealed, the method of amplifying large regions for long-read sequencing for the analysis of multiple inversion systems proved effective.</p

Sustained ventricular arrhythmias among patients with acute coronary syndromes with no ST-segment elevation: incidence, predictors, and outcomes

BACKGROUND: The prognosis of ventricular arrhythmias among patients with non-ST-elevation acute coronary syndromes is unknown. We studied the incidence, predictors, and outcomes of sustained ventricular arrhythmias in 4 large randomized trials of such patients. METHODS AND RESULTS: We pooled the datasets of the Global Use of Streptokinase and tPA for Occluded Arteries (GUSTO)-IIb, Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT), Platelet IIb/IIIa Antagonism for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network (PARAGON)-A, and PARAGON-B trials (n=26 416). We identified independent predictors of ventricular fibrillation (VF) and ventricular tachycardia (VT) and compared the 30-day and 6-month mortality rates of patients who did (n=552) and did not (n=25 864) develop these arrhythmias during the index hospitalization. Independent predictors of in-hospital VF included prior hypertension, chronic obstructive pulmonary disease, prior myocardial infarction, and ST-segment changes at presentation. Except for hypertension, these variables also independently predicted in-hospital VT. In Cox proportional-hazards modeling, in-hospital VF and VT were independently associated with 30-day mortality (hazard ratio [HR], 23.2 [95% CI, 18.1 to 29.8] for VF and HR, 7.6 [95% CI, 5.5 to 10.4] for VT) and 6-month mortality (HR, 14.8 [95% CI, 12.1 to 18.3] for VF and HR, 5.0 [95% CI, 3.8 to 6.5] for VT). These differences remained significant after excluding patients with heart failure or cardiogenic shock and those who died <24 hours after enrollment. CONCLUSIONS: Despite the use of effective therapies for non-ST-elevation acute coronary syndromes, ventricular arrhythmias in this setting are associated with increased 30-day and 6-month mortality. More effective therapies are needed to improve the survival of patients with these arrhythmias