Sporadic E layers form in the daytime midlatitude ionosphere as a
result of wind shears in the mesosphere–lower-thermosphere compressing
metallic ions of meteoric origin into dense, narrow sheets ...extending over
hundreds or thousands of kilometers spatially. These layers are poorly
observed, being too narrow to be properly resolved by incoherent scatter
radar or path-integrated total electron content measurements. Sporadic E
layer peak densities can be resolved by ionosondes and by rocket-borne
Langmuir probes, but these techniques have major limitations in terms of
spatial and temporal coverage, and (for many ionosondes) maximum density
resolution. As a result, the density, occurrence, and spatial extent of
sporadic E layers are not well constrained by observations. The maximum
density of sporadic E is widely believed to be around 5–10×1011 electrons m−3 NmEs (equivalent to 6–9 MHz foEs), though
there are a few isolated reports of layers extending beyond 20 MHz (Chandra
and Rastogi, 1975; Maeda and Heki, 2014). Here, we identify sporadic E
layers using a huge database of 29 million 162 MHz automatic identification system (AIS) shipping transmissions collected over 3 d by a United
States Coast Guard (USCG) terrestrial monitoring network in the eastern
United States and Puerto Rico. Within this dataset, most (>99 %) links are explained by line-of-sight, surface-wave, and tropospheric
propagation, but a small population cannot be explained by these mechanisms.
In total, 6677 signals were identified from ships located over 1000 km from
the ground stations between 13 and 14 July 2021, and almost no long-distance
links were received at night or at any time on 15 July. This coincides with
intense (saturated) sporadic E in collocated ionosondes and in satellite
radio occultation data. The density of these layers might exceed 27 MHz
foEs or 9×1012 electrons m−3 NmEs. AIS transmissions
potentially provide an excellent means of identifying dense sporadic E
layers globally.
•A rotating perfusion reactor with spiroid improves oxygen mass transfer.•The mechanism was based on increasing the interfacial surface between gas and liquid.•Oxygen saturation was two times faster ...with the spiroid.
This research investigates a novel continuous bioreactor with significant improvement in gas-liquid transport phenomena. This bioreactor is an automated, horizontally-rotating bioreactor consisting of an outer cylindrical shell and a core with adjustable rotating velocities operated in continuous mode. The under-filled bioreactor provides a multiphase environment for the cell line beneficial for improving the gas-liquid transport phenomena. A spiroid tube is embedded in the inner surface of the outer wall of the bioreactor to increase gas-liquid contact area and thus improve oxygen transfer. Computational fluid dynamics simulations were performed to determine the optimum operating conditions for oxygen transfer. The oxygen transfer rates were determined experimentally, and the related volumetric mass transfer coefficients (kLa) were predicted by mathematical models at a variety of operating conditions. The results indicate that the reactor with the spiroid reached saturation approximately two times faster than without the spiroid.
The widespread use of nanomaterials in vaccines, therapeutics, and industrial applications creates an increasing demand for understanding their ingestion by living cells. Researchers in the field ...have called for a more robust understanding of physical/chemical particle–cell interactions and a means to determine the particles ingested per cell. Using superparamagnetic nanobeads, we measured the beads per cell and quantified the kinetics of the receptor-independent endocytosis of particles having seven surface chemistries. Poly(ethylene glycol) (PEG)-coated nanoparticles were ingested less effectively by cultured Chinese hamster ovary (CHO-K1) cells and more effectively by aminated nanoparticles than starch-coated particles. The cells ingested 2 to 4 × 105 of the most attractive particles. The interplay between Van der Waals and coulombic potentials was quantified on the basis of Derjaguin–Landau–Verwey–Overbeek (DLVO) theory modified to include hydration repulsion using physical parameters of the seven surface chemistries. Using dose–response curves for inhibitors of clathrin- or caveolae-dependent ingestion, we quantified how particle surface chemistry determines which endocytic pathway is used by the cell. Such characterization can be useful in predicting nanomaterial uptake in medical and toxicological applications and in the selection of particle surface chemistries for receptor-dependent endocytosis.
Intelectin-1 (ITLN1) is a lectin secreted by intestinal epithelial cells (IECs) and upregulated in human ulcerative colitis (UC). We investigated how ITLN1 production is regulated in IECs and the ...biological effects of ITLN1 at the host-microbiota interface using mouse models. Our data show that ITLN1 upregulation in IECs from UC patients is a consequence of activating the unfolded protein response. Analysis of microbes coated by ITLN1 in vivo revealed a restricted subset of microorganisms, including the mucolytic bacterium Akkermansia muciniphila. Mice overexpressing intestinal ITLN1 exhibited decreased inner colonic mucus layer thickness and closer apposition of A. muciniphila to the epithelial cell surface, similar to alterations reported in UC. The changes in the inner mucus layer were microbiota and A. muciniphila dependent and associated with enhanced sensitivity to chemically induced and T cell-mediated colitis. We conclude that by determining the localization of a select group of bacteria to the mucus layer, ITLN1 modifies this critical barrier. Together, these findings may explain the impact of ITLN1 dysregulation on UC pathogenesis.
The use of magnetophoretic mobility as a surrogate for fluorescence intensity in quantitative cell analysis was investigated. The objectives of quantitative fluorescence flow cytometry include ...establishing a level of labeling for the setting of parameters in fluorescence activated cell sorters (FACS) and the determination of levels of uptake of fluorescently labeled substrates by living cells. Likewise, the objectives of quantitative magnetic cytometry include establishing a level of labeling for the setting of parameters in flowing magnetic cell sorters and the determination of levels of uptake of magnetically labeled substrates by living cells. The magnetic counterpart to fluorescence intensity is magnetophoretic mobility, defined as the velocity imparted to a suspended cell per unit of magnetic ponderomotive force. A commercial velocimeter available for making this measurement was used to demonstrate both applications. Cultured Gallus lymphoma cells were immunolabeled with commercial magnetic beads and shown to have adequate magnetophoretic mobility to be separated by a novel flowing magnetic separator. Phagocytosis of starch nanoparticles having magnetic cores by cultured Chinese hamster ovary cells, a CHO line, was quantified on the basis of magnetophoretic mobility.
•Commercial particle tracking velocimetry measures magnetophoretic mobility of labeled cells.•Magnetically labeled tumor cells were shown to have adequate mobility for capture in a specific sorter.•The kinetics of nonspecific endocytosis of magnetic nanomaterials by CHO cells was characterized.•Magnetic labeling of cells can be used like fluorescence flow cytometry for quantitative cell analysis.
Recent results from the Multimodal Treatment Study of Attention-Deficit/Hyperactivity Disorder (ADHD; MTA) have demonstrated impairments in several functioning domains in adults with childhood ADHD. ...The childhood predictors of these adult functional outcomes are not adequately understood. The objective of the present study was to determine the effects of childhood demographic, clinical, and family factors on adult functional outcomes in individuals with and without childhood ADHD from the MTA cohort.
Regressions were used to determine associations of childhood factors (age range 7-10 years) of family income, IQ, comorbidity (internalizing, externalizing, and total number of non-ADHD diagnoses), parenting styles, parental education, number of household members, parental marital problems, parent-child relationships, and ADHD symptom severity with adult outcomes (mean age 25 years) of occupational functioning, educational attainment, emotional functioning, sexual behavior, and justice involvement in participants with (n = 579) and without (n = 258) ADHD.
Predictors of adult functional outcomes in ADHD included clinical factors such as baseline ADHD severity, IQ, and comorbidity; demographic factors such as family income, number of household members and parental education; and family factors such as parental monitoring and parental marital problems. Predictors of adult outcomes were generally comparable for children with and without ADHD.
Childhood ADHD symptoms, IQ, and household income levels are important predictors of adult functional outcomes. Management of these areas early on, through timely treatments for ADHD symptoms, and providing additional support to children with lower IQ and from households with low incomes, could assist in improving adult functioning.
There is an identified need for point-of-care diagnostic systems for detecting and counting specific rare types of circulating cells in blood. By adequately labeling such cells with immunomagnetic ...beads and quantum dots, they can be efficiently collected magnetically for quantification using fluorescence methods. Automation of this process requires adequate mixing of the labeling materials with blood samples. A static mixing device can be employed to improve cell labeling efficiency and eliminate error-prone laboratory operations. Computational fluid dynamics (CFD) were utilized to simulate the flow of a labeling-materials/blood mixture through a 20-stage in-line static mixer of the interfacial-surface-generator type. Optimal fluid mixing conditions were identified and tested in a magnetic bead/tumor cell model, and it was found that labeled cells could be produced at 1.0 mL/min flow rate and fed directly into an in-line magnetic trap. The trap design consists of a dual flow channel with three bends and a permanent magnet positioned at the outer curve of each bend. The capture of labeled cells in the device was simulated using CFD, finite-element analysis and magnetophoretic mobility distributions of labeled cells. Testing with cultured CRL14777 human melanoma cells labeled with anti-CD146 1.5 μm diameter beads indicated that 90 ± 10% are captured at the first stage, and these cells can be captured when present in whole blood. Both in-line devices were demonstrated to function separately and together as predicted.
The effects of precommercial thinning on the understory vegetative cover of 16- to 18-year-old spruce-hemlock (
Picea sitchensis
(Bong.) Carrière -
Tsuga heterophylla
(Raf.) Sarg.) stands were ...studied in seven replicate areas over seven growing seasons postthinning. Vegetative cover was analyzed at the class level, but species-specific effects were examined in relation to their value as food for Sitka black-tailed deer (
Odocoileus hemionus sitkensis
Cowan). When compared with unthinned controls, thinned stands (3.6-6.3 m spacing) had significantly greater understory cover. However, all thinned spacings led to similar understory cover. Conifer cover recovered to about two-thirds of its prethinning level within seven growing seasons posttreatment. Understory nonconiferous cover increased during the first 2-4 years postthinning but began to decline with increasing conifer cover during the next 3 years, nearly reaching pretreatment levels by year 7. In unthinned understories, vegetative cover had declined and was significantly lower than that beneath thinned stands. Summer food resource values for deer were increased by thinning. Winter food resource values were increased by thinning for snow-free conditions but were unaffected for conditions when herb-layer forbs were buried by snow.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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