We compare element and isotopic fractionations measured in bulk solar wind samples collected by NASA's Genesis mission with those predicted from models incorporating both the ponderomotive force in ...the chromosphere and conservation of the first adiabatic invariant in the low corona. Generally good agreement is found, suggesting that these factors are consistent with the process of solar wind fractionation. Based on bulk wind measurements, we also consider in more detail the isotopic and elemental abundances of O. We find mild support for an O abundance in the range 8.75-8.83, with a value as low as 8.69 disfavored. A stronger conclusion must await solar wind regime-specific measurements from the Genesis samples.
NASA's Genesis Mission returned solar wind (SW) to the Earth for analysis to derive the composition of the solar photosphere from solar material. SW analyses control the precision of the derived ...solar compositions, but their ultimate accuracy is limited by the theoretical or empirical models of fractionation due to SW formation. Mg isotopes are “ground truth” for these models since, except for CAIs, planetary materials have a uniform Mg isotopic composition (within ≤1‰) so any significant isotopic fractionation of SW Mg is primarily that of SW formation and subsequent acceleration through the corona. This study analyzed Mg isotopes in a bulk SW diamond‐like carbon (DLC) film on silicon collector returned by the Genesis Mission. A novel data reduction technique was required to account for variable ion yield and instrumental mass fractionation (IMF) in the DLC. The resulting SW Mg fractionation relative to the DSM‐3 laboratory standard was (−14.4‰, −30.2‰) ± (4.1‰, 5.5‰), where the uncertainty is 2ơ SE of the data combined with a 2.5‰ (total) error in the IMF determination. Two of the SW fractionation models considered generally agreed with our data. Their possible ramifications are discussed for O isotopes based on the CAI nebular composition of McKeegan et al. (2011).
We compare element and isotopic fractionations measured in solar wind samples collected by NASA's Genesis mission with those predicted from models incorporating both the ponderomotive force in the ...chromosphere and conservation of the first adiabatic invariant in the low corona. Generally good agreement is found, suggesting that these factors are consistent with the process of solar wind fractionation. Based on bulk wind measurements, we also consider in more detail the isotopic and elemental abundances of O. We find mild support for an O abundance in the range 8.75 - 8.83, with a value as low as 8.69 disfavored. A stronger conclusion must await solar wind regime specific measurements from the Genesis samples.
The microstructures of two-phase binary aggregates of ice-I + salt-hydrate, prepared by eutectic solidification, have been characterized by cryogenic scanning electron microscopy (CSEM). The specific ...binary systems studied were H2O-Na2SO4, H2O-MgSO4, H2O-NaCl, and H2O-H2SO4; these were selected based on their potential application to the study of tectonics on the Jovian moon Europa. Homogeneous liquid solutions of eutectic compositions were undercooled modestly (ΔT approximately 1-5°C); similarly cooled crystalline seeds of the same composition were added to circumvent the thermodynamic barrier to nucleation and to control eutectic growth under (approximately) isothermal conditions. CSEM revealed classic eutectic solidification microstructures with the hydrate phase forming continuous lamellae, discontinuous lamellae, or forming the matrix around rods of ice-I, depending on the volume fractions of the phases and their entropy of dissolving and forming a homogeneous aqueous solution. We quantify aspects of the solidification behavior and microstructures for each system and, with these data, articulate anticipated effects of the microstructure on the mechanical responses of the materials.
Several lines of evidence suggest that pathologic changes underlying Alzheimer disease (AD) begin years prior to the clinical expression of the disease, underscoring the need for studies of ...cognitively healthy adults to capture these early changes. The overall goal of the current study was to map the cortical distribution of β-amyloid (Aβ) in a healthy adult lifespan sample (aged 30-89), and to assess the relationship between elevated amyloid and cognitive performance across multiple domains.
A total of 137 well-screened and cognitively normal adults underwent Aβ PET imaging with radiotracer (18)F-florbetapir. Aβ load was estimated from 8 cortical regions. Participants were genotyped for APOE and tested for processing speed, working memory, fluid reasoning, episodic memory, and verbal ability.
Aβ deposition is distributed differentially across the cortex and progresses at varying rates with age across cortical brain regions. A subset of cognitively normal adults aged 60 and over show markedly elevated deposition, and also had a higher rate of APOE ε4 (38%) than nonelevated adults (19%). Aβ burden was linked to poorer cognitive performance on measures of processing speed, working memory, and reasoning.
Even in a highly selected lifespan sample of adults, Aβ deposition is apparent in some adults and is influenced by APOE status. Greater amyloid burden was related to deleterious effects on cognition, suggesting that subtle cognitive changes accrue as amyloid progresses.
Despite much work studying ex vivo multipotent stromal cells (MSCs), the identity and characteristics of MSCs in vivo are not well defined. Here, we generated a CD73-EGFP reporter mouse to address ...these questions and found EGFP+ MSCs in various organs. In vivo, EGFP+ mesenchymal cells were observed in fetal and adult bones at proliferative ossification sites, while in solid organs EGFP+ cells exhibited a perivascular distribution pattern. EGFP+ cells from the bone compartment could be clonally expanded ex vivo from single cells and displayed trilineage differentiation potential. Moreover, in the central bone marrow CD73-EGFP+ specifically labeled sinusoidal endothelial cells, thought to be a critical component of the hematopoietic stem cell niche. Purification and molecular characterization of this CD73-EGFP+ population revealed an endothelial subtype that also displays a mesenchymal signature, highlighting endothelial cell heterogeneity in the marrow. Thus, the CD73-EGFP mouse is a powerful tool for studying MSCs and sinusoidal endothelium.
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•CD73-EGFP labels multipotent stromal cells (MSCs) in various tissues•CD73-EGFP allows purification of MSCs from the bone compartment•CD73-EGFP also marks bone marrow sinusoidal cells enabling their purification•RNA-seq analysis reveals endothelial heterogeneity within the bone marrow
Breitbach et al. generated a CD73-EGFP reporter mouse that enabled identification and tracking of multipotent stromal cells in vivo. CD73-EGFP also labeled sinusoidal endothelial cells within the bone marrow, enabling the molecular characterization of this important endothelial component of the hematopoietic stem cell niche.
To evaluate the indications, visual outcomes, and complication rate after implantation of a posterior chamber iris-claw aphakic intraocular lens (IOL).
Department of Ophthalmology, University ...Medicine Charité Berlin, Berlin, Germany.
Retrospective case series.
Eyes without adequate capsule support had posterior chamber iris-claw aphakic IOL implantation (Verisyse/Artisan) between 2005 and 2010.
The study comprised 137 eyes (126 patients). The mean follow-up was 5 months (range 1 to 48 months). The IOLs were inserted during primary lens surgery in 10 eyes (7.3%), during an IOL exchange procedure for dislocated posterior chamber IOLs in 95 eyes (69.4%), and as a secondary procedure in 32 aphakic eyes (23.3%). The final mean corrected distance visual acuity (CDVA) (0.38 ± 0.31 SD logMAR) was significantly better than preoperatively (0.65 ± 0.58 logMAR) (P < .05). In 128 eyes (93.4%), postoperative refractive errors were within ±2.00 diopters (D) of emmetropia. Complications included slight temporary pupil ovalization in 34 eyes (24.8%), cystoid macular edema in 12 eyes (8.7%), hyphema in 3 eyes (2.1%), early postoperative hypotony in 7 eyes (5.1%) and elevated intraocular pressure in 6 eyes (4.3%), chronic uveitis in 1 eye (0.7%), toxic anterior segment syndrome in 1 eye (0.7%), and endophthalmitis in 1 eye (0.7%). Iris-claw IOL disenclavation occurred in 12 eyes (8.7%); all IOLs could be easily repositioned.
The retropupillary iris-claw IOL provided good visual outcomes with a favorable complication rate and can be used for a wide range of indications in eyes without adequate capsule support.
No author has a financial or proprietary interest in any material or method mentioned.
Several indirect clinical tests for measuring hamstring muscle length are available, but the influence of their test procedures is not well documented. This study examined four of these tests to ...clarify the results relative to the testing procedures. The right limbs of 30 men were tested for: 1) passive straight leg raise (SLR) with the pelvis and opposite thigh stabilized with straps (SLR-SS); 2) passive SLR with the low back flat and, if needed, the opposite thigh slightly flexed and supported on pillows (SLR-LBF); 3) active knee extension with the hip at 90 degrees (AKE); and 4) passive knee extension with the hip at 90 degrees (PKE). A dependent t-test showed no significant differences between the angles of SLR-SS (61 degrees +/- 6.7 degrees) and SLR-LBF (62 degrees +/- 6.2 degrees). The SLR-SS and SLR-LBF angles for subjects needing pillows under the opposite thigh for the SLR-LBF test (N = 18) also were not significantly different. The knee flexion angles for the AKE (43 degrees +/- 10.2 degrees) and the PKE (31 degrees +/- 7.5 degrees) tests were significantly different (p < 0.001). Significant relationships (Pearson r) were found among the four tests (p < 0.05). The similar angles for SLR-SS and SLR-LBF and their significant relationship (r = 0.70, p < 0.001) indicated that their different testing procedures probably had a minimal influence on test results. The difference between the AKE and PKE tests suggested that the AKE test and the PKE test may represent an "initial length" and a "maximal length," respectively.
Purpose For surface replacement arthroplasty in proximal interphalangeal joint osteoarthritis, titanium-polyethylene (TI) and pyrocarbon (PY) implants are frequently used. However, their superiority ...in comparison to the silicone (SI) spacer has not been established. The purpose of this study was to compare these 3 types of implants with regard to outcome. Methods A prospective, randomized, multicenter trial was performed. A total of 43 patients (62 proximal interphalangeal joints) had surgery in the 3 participating centers, and each patient was randomly allocated to one of the 3 groups (TI, PY, SI). Range of motion (ROM) and strength were measured before surgery; pain and disability self-assessment and radiographic analysis were also completed. The same examination protocol was planned for 3 months, 6 months, and 1, 2, and 3 years after surgery, but some follow-up visits did not take place due to patient death or poor compliance. Results The mean follow-up time at the final follow-up was 35 ± 3 months (range, 30–41 mo). All implant types led to significant pain reduction at rest and at load. Tip pinch strength was slightly improved by all 3 devices at the 3-year follow-up. No significant improvement in ROM for silicone or resurfacing implants was found. However, when comparing the highest ROM values reached after surgery, the resurfacing devices tended to show superior joint motility compared to silicone spacers, albeit only temporarily and not significantly. Sixteen explantations were necessary: 2 of 18 SI (11%), 7 of 26 TI (27%) and 7 of 18 PY (39%) implants had to be removed. An additional 4 secondary surgical procedures were performed in group TI. Conclusions Surface replacement arthroplasty devices showed a tendency for a temporarily superior maximum postoperative ROM, but markedly higher postoperative complication and explantation rates were observed compared to the silicone spacer implantation. Type of study/level of evidence Therapeutic II.
We compare element and isotopic fractionations measured in solar wind samples collected by NASA's Genesis mission with those predicted from models incorporating both the ponderomotive force in the ...chromosphere and conservation of the first adiabatic invariant in the low corona. Generally good agreement is found, suggesting that these factors are consistent with the process of solar wind fractionation. Based on bulk wind measurements, we also consider in more detail the isotopic and elemental abundances of O. We find mild support for an O abundance in the range 8.75 - 8.83, with a value as low as 8.69 disfavored. A stronger conclusion must await solar wind regime specific measurements from the Genesis samples.
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