1,335 research outputs found
Scheimpflug-based analysis of the reflectivity of the cornea in Marfan Syndrome
Purpose:We sought to investigate corneal reflectivity inMarfan syndrome (MFS) on the basis of Scheimpflug light intensity distribution. Methods: In a retrospective case-control analysis, the left eyes of 40 MFS patients and 40 age- and refraction-matched healthy controls were investigated. Patients with MFS meeting the Ghent II diagnostic criteria and with genetic confirmation of disease were included. Exclusion criteria were the following: Coexisting corneal, conjunctival, or scleral pathology, use of medication known to affect corneal transparency, history of ocular surgery, and insufficient data. Scheimpflug tomography images were exported to analyze corneal transparency in different corneal layers and regions. Each corneal image was automatically segmented, after which the corresponding pixel intensities in the defined regions of interest were statistically modeled using a Weibull probability density function from which parameters a (transparency) and ß (homogeneity) were derived. Results: The cornea in MFS showed significantly higher light reflectivity (overall cornea, a = 71 ± 17 arbitrary units (a.u.)) than in the control group (overall cornea, a = 59 ± 15 a.u.) (t test, P = 0.003). The a parameter was significantly higher in MFS eyes in all examined layers and regions (P 0.05). The difference in a did not correlate with ocular biometric properties (corneal thickness and curvature) or ectopia lentis (P> 0.05). Conclusions: The cornea in MFS shows significantly higher reflectivity than healthy controls with similar levels of homogeneity. Translational Relevance: The proposed methodology detects corneal reflectivity changes in MFS not available from regular slit-lamp examination
Cast Glance Near Infrared Imaging Observations of the Space Shuttle During Hypersonic Re-Entry
High resolution calibrated infrared imagery of the Space Shuttle was obtained during hypervelocity atmospheric entries of the STS-119, STS-125 and STS128 missions and has provided information on the distribution of surface temperature and the state of the airflow over the windward surface of the Orbiter during descent. This data collect was initiated by NASA s Hypersonic Thermodynamic Infrared Measurements (HYTHIRM) team and incorporated the use of air- and land-based optical assets to image the Shuttle during atmospheric re-entry. The HYTHIRM objective is to develop and implement a set of mission planning tools designed to establish confidence in the ability of an existing optical asset to reliably acquire, track and return global quantitative surface temperatures of the Shuttle during entry. On Space Shuttle Discovery s STS-119 mission, NASA flew a specially modified thermal protection system tile and instrumentation package to monitor heating effects from boundary layer transition during re-entry. On STS-119, the windward airflow on the port wing was deliberately disrupted by a four-inch wide and quarter-inch tall protuberance built into the modified tile. In coordination with this flight experiment, a US Navy NP-3D Orion aircraft was flown 28 nautical miles below Discovery and remotely monitored surface temperature of the Orbiter at Mach 8.4 using a long-range infrared optical package referred to as Cast Glance. Approximately two months later, the same Navy Cast Glance aircraft successfully monitored the surface temperatures of the Orbiter Atlantis traveling at approximately Mach 14.3 during its return from the successful Hubble repair mission. In contrast to Discovery, Atlantis was not part of the Boundary Layer Transition (BLT) flight experiment, thus the vehicle was not configured with a protuberance on the port wing. In September 2009, Cast Glance was again successful in capturing infrared imagery and monitoring the surface temperatures on Discovery s next flight, STS-128. Again, NASA flew a specially modified thermal protection system tile and instrumentation package to monitor heating effects from boundary layer transition during re-entry. During this mission, Cast Glance was able to image laminar and turbulent flow phenomenology optimizing data collection for Mach 14.7. The purpose of this paper is to describe key elements associated with STS-119/125/128 mission planning and execution from the perspective of the Cast Glance flight crew that obtained the imagery. The paper will emphasize a human element of experience, expertise and adaptability seamlessly coupled with Cast Glance system and sensor technology required to manually collect the required imagery. Specific topics will include a near infrared (NIR) camera upgrade that was implemented just prior to the missions, how pre-flight radiance modeling was utilized to optimize the IR sensor configuration, communications, the development of aircraft test support positions based upon Shuttle trajectory information, support to contingencies such as Shuttle one orbit wave-offs/west coast diversions and then the Cast Glance perspective during an actual Shuttle imaging mission
Speciation of vanadium in the dissolved, colloidal, and sediment phase under dynamic redox-conditions in a V contaminated soil treated and untreated with biochar
Vanadium is a redox-sensitive toxic element and can exist in a variety of oxidation states: −1, 0, +2, +3, +4, and +5. Vanadium (+5) is considered as a potentially dangerous pollutant. Biochar (BC) can be used to remediate soils contaminated with potential toxic elements (PTEs) including V. However, the efficiency of BC to immobilize V and its on speciation of V in the dissolved and colloidal phase and its mobilization and phytoavailability in the sediment phase under dynamic redox-conditions in highly contaminated soils under dynamic redox conditions has not been studied up to date. Thus, we have i) quantified the impact of pre-definite redox conditions on the speciation and release dynamics of V in the dissolved and colloidal phase as well as on the mobilization and phytoavailability of V in the soil sediments phase in a highly contaminated alkaline soil (CS) (non-treated) (pH = 7.44 and total V = 1,040 mg kg-1) collected from China and in the same soil treated with BC (CS+BC), and ii) assessed the impact of rice husk biochar as soil amendment on the same parameters. The impact of redox potential (EH), pH, dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), iron (Fe), manganese (Mn), and sulfate (SO42-) on speciation and release dynamics of V was also determined under dynamic redox conditions. In addition, the used biochar was characterized using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) and nuclear magnetic resonance spectroscopy (NMR). The experiment was conducted in stepwise from moderate reducing (-30 mV in CS and -12 mV in CS+BC) to oxidizing (+218 mV in CS and +333 mV in CS+BC) soil conditions in different cycles using a highly sophisticated automated biogeochemical microcosm apparatus.
Flooding of the CS and CS+BC caused significant changes of pH values which varied from 6.15 to 8.33 in the CS and from 5.14 to 7.91 in the CS+BC and the EH correlated negatively with pH. The dissolved concentrations of V varied from 15.2-46.4 mg L-1 in the CS to 14.9-50.2 mg L-1 in the CS+BC, while the colloidal concentrations of V varied from 39.5-49.9 mg L-1 in the CS to 31.8-50.2 mg L-1 in the CS+BC.
Different redox cycles affected significantly the speciation and release dynamics of V in the dissolved and colloidal phase and its mobilization and phytoavailability in the sediment phase
Factors affecting metal mobilisation during oxidation of sulphidic, sandy wetland substrates
Most metals accumulate as sulphides under anoxic conditions in wetland substrates, reducing their bioavailability due to the solubility of metal sulphides. However, upon oxidation of these sulphides when the substrate is occasionally oxidised, metals can be released from the solid phase to the pore water or overlaying surface water. This release can be affected by the presence of carbonates, organic matter and clay. We compared changes of Cd, Cu and Zn mobility (CaCl2 extraction) during oxidation of a carbonate-rich and a carbonate-poor sulphidic, sandy wetland substrate. In addition, we studied how clay with low and high cation sorption capacity (bentonite and kaolinite, respectively) and organic matter (peat) can counteract Cd, Cu and Zn release during oxidation of both carbonate-rich and carbonate-poor sulphidic sediments. CaCl2-extractability of Cu, a measure for its availability, is low in both carbonate-poor and carbonate-rich substrates, whereas its variability is high. The availability of Cd and Zn is much higher and increases when peat is supplied to carbonate-poor substrates. A strong reduction of Cd and Zn extractability is observed when clay is added to carbonate-poor substrates. This reduction depends on the clay type. Most observations could be explained taking into account pH differences between treatments, with kaolinite resulting in a lower pH in comparison to bentonite. These pH differences affect the presence and characteristics of dissolved organic carbon and the metal speciation, which in turns affects the interaction of metals with the solid soil phase. In carbonate-rich substrates, Cd and Zn availability is lower and the effects of peat and clay amendment are less clear. The latter can also be attributed to the high pH and lack of pH differences between treatments
The placebo response rate in pharmacological trials in patients with irritable bowel syndrome: a systematic review and meta-analysis
Findings Between June 16, 2014, and July 28, 2017, 122 patients were eligible for screening and a total of 95 patients were randomly assigned to the infliximab-continued group (n=48) or the infliximab-discontinued group (n=47). 92 patients (n=46 for both groups) were included in the full analysis set. 37 (80.4% [95% CI 66.1-90.6]) of 46 patients in the infliximab-continued group and 25 (54.3% [39.0-69.1]) of 46 patients in the infliximab-discontinued group were in remission at week 48. The between-group difference was 26.1% (95% CI 7.7-44.5; p=0.0076) before adjustment and 27.3% (95% CI 8.0-44.1; p=0.0059) after adjustment for stratification factors. Eight (17%) of 48 patients in the infliximab-continued group and six (13%) of 47 in the infliximab-discontinued group developed adverse events (between-group difference 3.9% [95% CI -10.3 to 18.1]; p=0.59). In the infliximab-continued group, one patient had an infusion reaction and two patients had psoriatic skin lesions. Eight (66.7%, 95% CI 34.9-90.1) of the 12 patients in the infliximab-discontinuation group who were re-treated with infliximab after relapsing were in remission within 8 weeks of re-treatment; none had infusion reactions.Background Anti-tumour necrosis factor (TNF) agents are the mainstay of long-term treatment for refractory ulcerative colitis. However, long-term use of anti-TNF therapy might lead to an increased risk of malignancy or infection. To date, no randomised controlled trial has evaluated whether anti-TNF agents can be safely discontinued in patients with ulcerative colitis in remission. We therefore aimed to compare outcomes in these patients who continued infliximab with those who discontinued infliximab.Methods We did a multicentre, open-label randomised controlled trial at 24 specialist centres in Japan. We enrolled patients with ulcerative colitis who were in remission, had been treated with intravenous infliximab (5 mg/kg) every 8 weeks, and had started infliximab at least 14 weeks before study enrolment. No restrictions regarding age and comorbidities were used to exclude participation. Patients who were confirmed to be in remission for more than 6 months, to be corticosteroid-free, and to have a Mayo Endoscopic Subscore (MES) of 0 or 1 were centrally randomised. An independent organisation randomly assigned patients (1:1) into either the infliximab-continued group or infliximab-discontinued group, using a computer-generated stratified randomisation procedure. The stratified factors were the use of immunomodulators (yes or no) and MES (0 or 1). Neither patients nor health-care providers were masked to the randomisation. The primary endpoint was the remission rate at week 48 in the full analysis set, which was based on the intention-to-treat principle and excluded participants with no efficacy data after randomisation. This study was registered with the University Hospital Medical Information Network Center Trials registry, UMIN000012092. Findings Between June 16, 2014, and July 28, 2017, 122 patients were eligible for screening and a total of 95 patients were randomly assigned to the infliximab-continued group (n=48) or the infliximab-discontinued group (n=47). 92 patients (n=46 for both groups) were included in the full analysis set. 37 (80.4% [95% CI 66.1-90.6]) of 46 patients in the infliximab-continued group and 25 (54.3% [39.0-69.1]) of 46 patients in the infliximab-discontinued group were in remission at week 48. The between-group difference was 26.1% (95% CI 7.7-44.5; p=0.0076) before adjustment and 27.3% (95% CI 8.0-44.1; p=0.0059) after adjustment for stratification factors. Eight (17%) of 48 patients in the infliximab-continued group and six (13%) of 47 in the infliximab-discontinued group developed adverse events (between-group difference 3.9% [95% CI & minus;10.3 to 18.1]; p=0.59). In the infliximab-continued group, one patient had an infusion reaction and two patients had psoriatic skin lesions. Eight (66.7%, 95% CI 34.9-90.1) of the 12 patients in the infliximab-discontinuation group who were re-treated with infliximab after relapsing were in remission within 8 weeks of re-treatment; none had infusion reactions.Interpretation Maintenance of remission was significantly more common in patients who continued infliximab than in those who discontinued. Discontinuing infliximab should therefore be discussed with caution, taking both risk of relapse and efficacy of re-treatment into account.Funding Mitsubishi Tanabe Pharma Corporation and the Intractable Disease Project of the Ministry of Health, Labour and Welfare of Japan.Copyright (c) 2021 Elsevier Ltd. All rights reserved
Lack of Relationship Between Chronic Upper Abdominal Symptoms and Gastric Function in Functional Dyspepsia
To determine the relationship between gastric function and upper abdominal sensations we studied sixty FD patients (43 female). All patients underwent three gastric function tests: 13C octanoic gastric emptying test, three-dimensional ultrasonography (proximal and distal gastric volume), and the nutrient drink test. Upper abdominal sensations experienced in daily life were scored using questionnaires. Impaired proximal gastric relaxation (23%) and a delayed gastric emptying (33%) are highly prevalent in FD patients; however, only a small overlap exists between the two pathophysiologic disorders (5%). No relationship was found between chronic upper abdominal symptoms and gastric function (proximal gastric relaxation, gastric emptying rate, or drinking capacity) (all PÂ >Â 0.01). Proximal gastric relaxation or gastric emptying rate had no effect on maximum drinking capacity (PÂ >Â 0.01). The lack of relationship between chronic upper abdominal sensations and gastric function questions the role of these pathophysiologic mechanisms in the generation of symptoms
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