scholarly journals Intense interactions between ocean waves and currents observed in the Lofoten Maelstrom

2021 ◽  
Author(s):  
Øyvind Saetra ◽  
Trygve Halsne ◽  
Ana Carrasco ◽  
Øyvind Breivik ◽  
Torstein Pedersen ◽  
...  
Keyword(s):  
Wave Breaking ◽  
Ocean Waves ◽  
Energy Balance Equation ◽  
Horizontal Gradients ◽  
Strong Current ◽  
Strongly Connected ◽  
Waves And Currents ◽  
The Impact ◽  
First Time

AbstractThe Lofoten Maelstrom has been known for centuries as one of the strongest open-ocean tidal currents in the world, estimated to reach 3 m s−1, and by some estimates as much as 5 m s−1. The strong current gives rise to choppy seas when waves enter the Moskenes Sound, making the area extremely difficult to navigate. Despite its reputation, few studies of its strength exist and no stationary in situ measurements for longer time periods have been made due to the challenging conditions. By deploying for the first time in situ wave and current instruments, we confirm some previous estimates of the strength of the current. We also show that its strength is strongly connected with wave breaking. From a consideration of specific forcing terms in the dynamical energy balance equation for waves on a variable current, we assess the impact of the underlying current using a convenient metric formulated as a function of the horizontal current gradients. We find that the horizontal gradients are a likely explanation for the observed enhanced wave breaking during strong currents at a rising tide.

scholarly journals Novel Bionanocellulose/κ-Carrageenan Composites for Tissue Engineering

2018 ◽  
Vol 8 (8) ◽  
pp. 1352 ◽  
Author(s):  
Izabela Cielecka ◽  
Marcin Szustak ◽  
Edyta Gendaszewska-Darmach ◽  
Halina Kalinowska ◽  
Małgorzata Ryngajłło ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Chondrogenic Differentiation ◽  
Expression Patterns ◽  
Swelling Properties ◽  
In Situ Method ◽  
Chondrogenic Phenotype ◽  
The Impact ◽  
First Time ◽  
Water Holding

In this work, novel bacterial cellulose/κ-carrageenan (BNC/κ-Car) composites, being potential scaffolds for tissue engineering (TE), and outperforming the two polymers when used as scaffolds separately, were for the first time obtained using an in situ method, based on the stationary culture of bacteria Komagateibacter xylinus E25. The composites were compared with native BNC in terms of the morphology of fibers, chemical composition, crystallinity, tensile and compression strength, water holding capacity, water retention ratio and swelling properties. Murine chondrogenic ATDC5 cells were applied to assess the utility of the BNC/κ-Car composites as potential scaffolds. The impact of the composites on the cells viability, chondrogenic differentiation, and expression patterns of Col1α1, Col2α1, Runx2, and Sox9, which are indicative of ATDC5 chondrogenic differentiation, was determined. None of the composites obtained in this study caused the chondrocyte hypertrophy. All of them supported the differentiation of ATDC5 cells to more chondrogenic phenotype.

Propagation of Regular HCl Acids in Carbonate Rocks: The Impact of an In Situ Gelled Acid Stage

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Ahmed M. Gomaa ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Material Balance ◽  
Chemical Species ◽  
Field Studies ◽  
Injection Rate ◽  
The Core ◽  
The Impact ◽  
First Time ◽  
Recent Laboratory ◽  
Injection Rates

Recent laboratory and field studies indicated that polymer-based in situ gelled acids can cause formation damage. Coreflood experiments using single-stage and multistage acids were conducted at 250 °F. 15 wt. % regular HCl and 5 wt. % in situ gelled acid-based on Fe(III) as a crosslinker were the acids that were used in this study. Propagation of acids and crosslinker inside 20 in. long cores was examined for the first time in detail. Stage volume and injection rate, which were the parameters that affect the propagating of various chemical species, were examined. Samples of the core effluent were collected and the concentrations of calcium, crosslinker, and acid were measured. Material balance was conducted to determine the amount of cross-liker that retained in the core. The results show that in situ gelled acid should be pumped at low injection rates. In situ gelled acid at low injection rate instantaneously plugged the tip of the wormhole and did not create additional wormholes inside the core. Therefore, when the final regular acid stage bypassed the gel, it started to propagate from nearly the last point that the first stage ended. In site gelled acid stage volume should not exceed 0.5 PV. No benefits were gained by increasing the volume of in situ gelled acids. Retention of total iron in the core increased in multistage acid treatments, especially at low acid injection rates.

scholarly journals 2.1.2 Preliminary Results of the Micrometeoroid Experiment on Board Helios A

1976 ◽  
Vol 31 ◽  
pp. 159-163
Author(s):  
E. Grün ◽  
J. Kissel ◽  
H. Fechtig ◽  
P. Gammelin ◽  
H.-J. Hoffmann
Keyword(s):  
Interplanetary Dust ◽  
Strong Increase ◽  
The Sun ◽  
Impact Rate ◽  
M 10 ◽  
Large Particles ◽  
The Impact ◽  
First Time ◽  
Measured Particle

AbstractFor the first time in situ measurements of interplanetary dust have been performed between 0.3 AU and 1 AU from the sun by the micrometeoroid experiment on board Helios A. The measured particle masses are between 10−15 g and 10−8 g and their measured speeds are between 2 km/sec and 20 km/sec. Particle impacts are identified by the time-of-flight spectra of the ions released upon impact. 15 large particles (m ≥ 10−12 g) were detected from Dec. 15, 1974 to Sept. 5, 1975. They show a strong increase of the impact rate (appr. a factor of 10) between 1 AU and 0.3 AU. The directions from which they impacted the sensor are concentrated between the solar direction and the apex direction of the Helios spacecraft.

scholarly journals Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010

2012 ◽  
Vol 12 (17) ◽  
pp. 8257-8270 ◽  
Author(s):  
A. C. Nölscher ◽  
J. Williams ◽  
V. Sinha ◽  
T. Custer ◽  
W. Song ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Canopy ◽  
Marked Change ◽  
Reactive Species ◽  
Organic Precursor ◽  
The Impact ◽  
First Time ◽  
Comparative Reactivity

Abstract. Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyytiälä (Latitude 61°51' N; Longitude 24°17' E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyytiälä United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The comparison between these two total OH reactivity measurements, absolute values and the temporal variation have been analyzed here. Stable boundary layer conditions during night and turbulent mixing in the daytime induced low and high short-term variability, respectively. The impact on total OH reactivity from biogenic emissions and associated photochemical products was measured under "normal" and "stressed" (i.e. prolonged high temperature) conditions. The advection of biomass burning emissions to the site caused a marked change in the total OH reactivity vertical profile. By comparing the OH reactivity contribution from individually measured compounds and the directly measured total OH reactivity, the size of any unaccounted for or "missing" sink can be deduced for various atmospheric influences. For "normal" boreal conditions a missing OH reactivity of 58%, whereas for "stressed" boreal conditions a missing OH reactivity of 89% was determined. Various sources of not quantified OH reactive species are proposed as possible explanation for the high missing OH reactivity.

scholarly journals Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010

2012 ◽  
Vol 12 (3) ◽  
pp. 7419-7452 ◽  
Author(s):  
A. C. Nölscher ◽  
J. Williams ◽  
V. Sinha ◽  
T. Custer ◽  
W. Song ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Canopy ◽  
Marked Change ◽  
Reactive Species ◽  
Organic Precursor ◽  
The Impact ◽  
First Time ◽  
Comparative Reactivity

Abstract. Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyytiälä (Latitude 61°51' N; Longitude 24°17' E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyytiälä United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The comparison between these two total OH reactivity measurements, absolute values and the temporal variation have been analyzed here. Stable boundary layer conditions during night and turbulent mixing in the daytime induced low and high short-term variability, respectively. The impact on total OH reactivity from biogenic emissions and associated photochemical products was measured under "normal" and "stressed" (i.e. prolonged high temperature) conditions. The advection of biomass burning emissions to the site caused a marked change in the total OH reactivity vertical profile. By comparing the OH reactivity contribution from individually measured compounds and the directly measured total OH reactivity, the size of any unaccounted for or "missing" sink can be deduced for various atmospheric influences. For "normal" boreal conditions a missing OH reactivity of 58%, whereas for "stressed" boreal conditions a missing OH reactivity of 89% was determined. Various sources of not quantified OH reactive species are proposed as possible explanation for the high missing OH reactivity.

scholarly journals Visualization of intestinal infections with astro- and sapovirus in mink (Neovison vison) kits by in situ hybridization

FEMS Microbes ◽  
2021 ◽  
Author(s):  
Julie Melsted Birch ◽  
Mikael Leijon ◽  
Søren Saxmose Nielsen ◽  
Tina Struve ◽  
Henrik Elvang Jensen
Keyword(s):  
In Situ Hybridization ◽  
Goblet Cells ◽  
Neovison Vison ◽  
Localization Pattern ◽  
Intestinal Infections ◽  
Specific Localization ◽  
The Impact ◽  
First Time ◽  
Mink Kits

Abstract Clarification of the infection microbiology remains a challenge in the pre-weaning diarrhea (PWD) syndrome in farmed mink (Neovison vison). Duodenal, jejunal and colon sections from 36 mink kits with PWD were systematically examined by chromogen in situ hybridization (CISH) targeting two incriminated viruses: Mink astrovirus and mink sapovirus. Using the RNAscope® 2.5 HD Duplex Assay astrovirus and sapovirus were visualized and simultaneously demonstrated in the gut tissue. Both viruses infect enterocytes in the small intestine with a specific localization pattern; astrovirus affects the two apical thirds of the villi, whereas sapovirus generally affects the basal parts of the villi. Furthermore, we demonstrated that astrovirus in mink does not target the goblet cells. This is the first time astro- and calicivirus have been visualized in mink kit gut tissue, and these findings might be important in clarification of the impact of these viruses in the PWD syndrome.

scholarly journals Light filter tailoring – the impact of light emitting diode irradiation on the morphology and optical properties of silver nanoparticles within polyethylenimine thin films

RSC Advances ◽  
2017 ◽  
Vol 7 (66) ◽  
pp. 41603-41609 ◽  
Author(s):  
F. Kemper ◽  
E. Beckert ◽  
R. Eberhardt ◽  
A. Tünnermann
Keyword(s):  
Thin Films ◽  
Silver Nanoparticles ◽  
Optical Properties ◽  
Light Emitting Diode ◽  
Light Filter ◽  
Light Emitting ◽  
Fluorescence Light ◽  
The Impact ◽  
First Time

In this contributionin situemission filter generation for,e.g.fluorescence light detection by morphology tailoring of silver nanoparticles within a polymer layer, is presented for the first time.

scholarly journals Dimension of aircraft exhaust plumes at cruise conditions: effect of wake vortices

2013 ◽  
Vol 13 (11) ◽  
pp. 30039-30096
Author(s):  
S. Unterstrasser ◽  
R. Paoli ◽  
I. Sölch ◽  
C. Kühnlein ◽  
T. Gerz
Keyword(s):  
Vertical Wind Shear ◽  
Vortex Pair ◽  
Aircraft Emissions ◽  
Cross Sectional ◽  
Tracer Distribution ◽  
Tracer Dilution ◽  
Les Model ◽  
The Impact ◽  
First Time

Abstract. The dispersion of aircraft emissions during the vortex phase is studied, for the first time using a 3-D LES model with Lagrangian particle tracking. The simulations start with a fully rolled-up vortex pair of a type B747/A340 airplane and the tracer centred around the vortex cores. The tracer dilution and plume extent is studied for a variety of ambient and aircraft parameters until aircraft-induced effects have deceased. For typical upper tropospheric conditions, the impact of stratification is more dominant compared to turbulence intensity or vertical wind shear. Moreover, the sensitivity to the initial tracer distribution was found to be weak. Along the transversal direction the tracer concentrations can be well approximated by a Gaussian distribution, along the vertical a superposition of three Gaussian distributions is adequate. For the studied parameter range the vertical plume expansion ranges from 400 m to 550 m and cross-sectional area from 4.0×104 m2 to 6.0×104 m2 after six minutes. For validation, selected simulations were compared to an alternative LES model and to in-situ NO-measurements.

scholarly journals Reactive Oxygen Species in Planarian Regeneration: An Upstream Necessity for Correct Patterning and Brain Formation

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Nicky Pirotte ◽  
An-Sofie Stevens ◽  
Susanna Fraguas ◽  
Michelle Plusquin ◽  
Andromeda Van Roten ◽  
...  
Keyword(s):  
Cell Sorting ◽  
Entire Body ◽  
Oxygen Species ◽  
Wound Site ◽  
Planarian Regeneration ◽  
Ros Burst ◽  
The Impact ◽  
First Time ◽  
Upstream Regulators

Recent research highlighted the impact of ROS as upstream regulators of tissue regeneration. We investigated their role and targeted processes during the regeneration of different body structures using the planarian Schmidtea mediterranea, an organism capable of regenerating its entire body, including its brain. The amputation of head and tail compartments induces a ROS burst at the wound site independently of the orientation. Inhibition of ROS production by diphenyleneiodonium (DPI) or apocynin (APO) causes regeneration defaults at both the anterior and posterior wound sites, resulting in reduced regeneration sites (blastemas) and improper tissue homeostasis. ROS signaling is necessary for early differentiation and inhibition of the ROS burst results in defects on the regeneration of the nervous system and on the patterning process. Stem cell proliferation was not affected, as indicated by histone H3-P immunostaining, fluorescence-activated cell sorting (FACS), in situ hybridization of smedwi-1, and transcript levels of proliferation-related genes. We showed for the first time that ROS modulate both anterior and posterior regeneration in a context where regeneration is not limited to certain body structures. Our results indicate that ROS are key players in neuroregeneration through interference with the differentiation and patterning processes.

Nanoplankton from the Galapagos Islands: michaelsarsia elegans gran and halopappus adriaticus schiller (coccolithophorids) with special reference to coccoliths and their unmineralized components

1984 ◽  
Vol 305 (1123) ◽  
pp. 183-199 ◽  
Keyword(s):  
Galapagos Islands ◽  
The Body ◽  
Galápagos Islands ◽  
Transmission Electron ◽  
Biological Concepts ◽  
The Impact ◽  
First Time ◽  
Whole Mounts ◽  
Made In

Marine plankton flagellates attributable to Michaelsarsia elegans Gran (type species of its genus) and Halopappus adriaticus Schiller (sensu Gaarder) have been investigated by means of scanning and transmission electron microscopy supplementing light microscopy of dry whole mounts prepared in situ in the Galapagos Islands. Some external features, notably coccolith arrangement, have been re-interpreted, and information on others added or amplified. Some of the new details include the body coccoliths, which have been shown to be more complex than previously supposed, the bar-crystallites in particular being compound in both taxa. In addition, unmineralized components are shown to be present in all types of coccolith. They include patternless membranes spread across the proximal faces of body coccoliths and occupying the apparently vacant centres of ring-shaped coccoliths, while a highly characteristic, fragile, reticulum is limited to the central areas of the elongated appendage links in both taxa. The impact of these findings on general biological concepts is discussed in a preliminary way, drawing on cognate data previously published for Ophiaster and Calciopappus . It is concluded that the presence of apical appendages (anterior or posterior) in each of these genera is an independently acquired adaptation to some as yet unknown environmental factor or factors, whereas coccolith substructure is phyletically more meaningful. This indicates that Michael-sarsia , to which H. adriaticus should be transferred, is more remote from the other two genera than has hitherto been supposed. Finally an attempt has been made, in the light of aff the evidence, to assess for the first time the possible functional significance of the unmineralized coccolith components and some constructive suggestions have been tentatively formulated. The paper ends with a factual summary in the form of revised taxonomic diagnoses for M. elegans , M. adriaticus and the genus Michaelsarsia .

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