- published: 15 Jan 2012
- views: 371
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Human sperm rheotaxis: a passive physical process. Zhuoran Zhang et al (2016), Scientific Reports http://dx.doi.org/10.1038/srep23553
A long-standing question in natural reproduction is how mammalian sperm navigate inside female reproductive tract and finally reach the egg cell, or oocyte. Recently, fluid flow was proposed as a long–range guidance cue for sperm navigation. Coitus induces fluid flow from oviduct to uterus, and sperm align themselves against the flow direction and swim upstream, a phenomenon termed rheotaxis. Whether sperm rheotaxis is a passive process dominated by fluid mechanics, or sperm actively sense and adapt to fluid flow remains controversial. Here we report the first quantitative study of sperm flagellar motion during human sperm rheotaxis and provide direct evidence indicating that sperm rheotaxis is a passive process. Experimental results show that there is no significant difference in flagellar beating amplitude and asymmetry between rheotaxis-turning sperm and those sperm swimming freely in the absence of fluid flow. Additionally, fluorescence image tracking shows no Ca2+ influx during sperm rheotaxis turning, further suggesting there is no active signal transduction during human sperm rheotaxis.
- published: 23 Mar 2016
- views: 51
Artificial rheotaxis. Jérémie Palacci et al (2015), Science Advances http://dx.doi.org/10.1126/sciadv.1400214 0142
Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes.
- published: 10 May 2015
- views: 105
Todd Hays is a coward, I don't even know why i'm training for him, its an easy win if he even shows up to fight.
- published: 23 Jun 2013
- views: 383
Rheotaxis
(Positive) Rheotaxis is a form of taxis seen in many aquatic organisms, e.g., fish, whereby they will (generally) turn to face into an oncoming current. This has been noted in zebrafish and other species.
In a flowing stream, this behavior leads them to hold position in a stream rather than being swept downstream by the current.
In fish that exhibit rheotaxis, it can easily be demonstrated by creating an artificial current within a tank using pumps. No matter which way the pumps force the current to flow, the fish will immediately turn to face the oncoming current.
Some fish will exhibit negative rheotaxis where they will avoid currents.
Some zooplankton also exhibit positive or negative rheotaxis.
Positive rheotaxis is found in most major aquatic invertebrate groups.
References
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This article is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License, which means that you can copy and modify it as long as the entire work (including additions) remains under this license.
This article is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License, which means that you can copy and modify it as long as the entire work (including additions) remains under this license.
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3:31Rheotaxis - Soul Collector
Rheotaxis - Soul Collector -
3:34Rheotaxis-welcome to room 666
Rheotaxis-welcome to room 666Rheotaxis-welcome to room 666
SICK SONG DEVASTATIN TO UR EAR PUSSY! -
0:43Human sperm rheotaxis: a passive physical process
Human sperm rheotaxis: a passive physical processHuman sperm rheotaxis: a passive physical process
Human sperm rheotaxis: a passive physical process. Zhuoran Zhang et al (2016), Scientific Reports http://dx.doi.org/10.1038/srep23553 A long-standing question in natural reproduction is how mammalian sperm navigate inside female reproductive tract and finally reach the egg cell, or oocyte. Recently, fluid flow was proposed as a long–range guidance cue for sperm navigation. Coitus induces fluid flow from oviduct to uterus, and sperm align themselves against the flow direction and swim upstream, a phenomenon termed rheotaxis. Whether sperm rheotaxis is a passive process dominated by fluid mechanics, or sperm actively sense and adapt to fluid flow remains controversial. Here we report the first quantitative study of sperm flagellar motion during human sperm rheotaxis and provide direct evidence indicating that sperm rheotaxis is a passive process. Experimental results show that there is no significant difference in flagellar beating amplitude and asymmetry between rheotaxis-turning sperm and those sperm swimming freely in the absence of fluid flow. Additionally, fluorescence image tracking shows no Ca2+ influx during sperm rheotaxis turning, further suggesting there is no active signal transduction during human sperm rheotaxis. -
2:24Artificial rheotaxis
Artificial rheotaxisArtificial rheotaxis
Artificial rheotaxis. Jérémie Palacci et al (2015), Science Advances http://dx.doi.org/10.1126/sciadv.1400214 0142 Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes. -
1:29Rheotaxis Training For The Fight With Todd Hays
Rheotaxis Training For The Fight With Todd HaysRheotaxis Training For The Fight With Todd Hays
Todd Hays is a coward, I don't even know why i'm training for him, its an easy win if he even shows up to fight.
-
-
Rheotaxis-welcome to room 666
SICK SONG DEVASTATIN TO UR EAR PUSSY! -
Human sperm rheotaxis: a passive physical process
Human sperm rheotaxis: a passive physical process. Zhuoran Zhang et al (2016), Scientific Reports http://dx.doi.org/10.1038/srep23553 A long-standing question in natural reproduction is how mammalian sperm navigate inside female reproductive tract and finally reach the egg cell, or oocyte. Recently, fluid flow was proposed as a long–range guidance cue for sperm navigation. Coitus induces fluid flow from oviduct to uterus, and sperm align themselves against the flow direction and swim upstream, a phenomenon termed rheotaxis. Whether sperm rheotaxis is a passive process dominated by fluid mechanics, or sperm actively sense and adapt to fluid flow remains controversial. Here we report the first quantitative study of sperm flagellar motion during human sperm rheotaxis and provide direct evide... -
Artificial rheotaxis
Artificial rheotaxis. Jérémie Palacci et al (2015), Science Advances http://dx.doi.org/10.1126/sciadv.1400214 0142 Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the exi... -
Rheotaxis Training For The Fight With Todd Hays
Todd Hays is a coward, I don't even know why i'm training for him, its an easy win if he even shows up to fight.
Rheotaxis - Soul Collector
- Order: Reorder
- Duration: 3:31
- Updated: 15 Jan 2012
- views: 371
Rheotaxis-welcome to room 666
- Order: Reorder
- Duration: 3:34
- Updated: 18 Jan 2009
- views: 1826
SICK SONG DEVASTATIN TO UR EAR PUSSY!
SICK SONG DEVASTATIN TO UR EAR PUSSY!
wn.com/Rheotaxis Welcome To Room 666
Human sperm rheotaxis: a passive physical process
- Order: Reorder
- Duration: 0:43
- Updated: 23 Mar 2016
- views: 51
Human sperm rheotaxis: a passive physical process. Zhuoran Zhang et al (2016), Scientific Reports http://dx.doi.org/10.1038/srep23553
A long-standing question ...
Human sperm rheotaxis: a passive physical process. Zhuoran Zhang et al (2016), Scientific Reports http://dx.doi.org/10.1038/srep23553
A long-standing question in natural reproduction is how mammalian sperm navigate inside female reproductive tract and finally reach the egg cell, or oocyte. Recently, fluid flow was proposed as a long–range guidance cue for sperm navigation. Coitus induces fluid flow from oviduct to uterus, and sperm align themselves against the flow direction and swim upstream, a phenomenon termed rheotaxis. Whether sperm rheotaxis is a passive process dominated by fluid mechanics, or sperm actively sense and adapt to fluid flow remains controversial. Here we report the first quantitative study of sperm flagellar motion during human sperm rheotaxis and provide direct evidence indicating that sperm rheotaxis is a passive process. Experimental results show that there is no significant difference in flagellar beating amplitude and asymmetry between rheotaxis-turning sperm and those sperm swimming freely in the absence of fluid flow. Additionally, fluorescence image tracking shows no Ca2+ influx during sperm rheotaxis turning, further suggesting there is no active signal transduction during human sperm rheotaxis.
wn.com/Human Sperm Rheotaxis A Passive Physical Process
Human sperm rheotaxis: a passive physical process. Zhuoran Zhang et al (2016), Scientific Reports http://dx.doi.org/10.1038/srep23553
A long-standing question in natural reproduction is how mammalian sperm navigate inside female reproductive tract and finally reach the egg cell, or oocyte. Recently, fluid flow was proposed as a long–range guidance cue for sperm navigation. Coitus induces fluid flow from oviduct to uterus, and sperm align themselves against the flow direction and swim upstream, a phenomenon termed rheotaxis. Whether sperm rheotaxis is a passive process dominated by fluid mechanics, or sperm actively sense and adapt to fluid flow remains controversial. Here we report the first quantitative study of sperm flagellar motion during human sperm rheotaxis and provide direct evidence indicating that sperm rheotaxis is a passive process. Experimental results show that there is no significant difference in flagellar beating amplitude and asymmetry between rheotaxis-turning sperm and those sperm swimming freely in the absence of fluid flow. Additionally, fluorescence image tracking shows no Ca2+ influx during sperm rheotaxis turning, further suggesting there is no active signal transduction during human sperm rheotaxis.
- published: 23 Mar 2016
- views: 51
Artificial rheotaxis
- Order: Reorder
- Duration: 2:24
- Updated: 10 May 2015
- views: 105
Artificial rheotaxis. Jérémie Palacci et al (2015), Science Advances http://dx.doi.org/10.1126/sciadv.1400214 0142
Motility is a basic feature of living microo...
Artificial rheotaxis. Jérémie Palacci et al (2015), Science Advances http://dx.doi.org/10.1126/sciadv.1400214 0142
Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes.
wn.com/Artificial Rheotaxis
Artificial rheotaxis. Jérémie Palacci et al (2015), Science Advances http://dx.doi.org/10.1126/sciadv.1400214 0142
Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes.
- published: 10 May 2015
- views: 105
Rheotaxis Training For The Fight With Todd Hays
- Order: Reorder
- Duration: 1:29
- Updated: 23 Jun 2013
- views: 383
Todd Hays is a coward, I don't even know why i'm training for him, its an easy win if he even shows up to fight.
Todd Hays is a coward, I don't even know why i'm training for him, its an easy win if he even shows up to fight.
wn.com/Rheotaxis Training For The Fight With Todd Hays
Todd Hays is a coward, I don't even know why i'm training for him, its an easy win if he even shows up to fight.
- published: 23 Jun 2013
- views: 383
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3:31
Rheotaxis - Soul Collector
Track 3 from the Room 666 EP released in 2005.
published: 15 Jan 2012
Rheotaxis - Soul Collector
Rheotaxis - Soul Collector
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- published: 15 Jan 2012
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3:34
Rheotaxis-welcome to room 666
SICK SONG DEVASTATIN TO UR EAR PUSSY!
published: 18 Jan 2009
Rheotaxis-welcome to room 666
Rheotaxis-welcome to room 666
- Report rights infringement
- published: 18 Jan 2009
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0:43
Human sperm rheotaxis: a passive physical process
Human sperm rheotaxis: a passive physical process. Zhuoran Zhang et al (2016), Scientific ...
published: 23 Mar 2016
Human sperm rheotaxis: a passive physical process
Human sperm rheotaxis: a passive physical process
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2:24
Artificial rheotaxis
Artificial rheotaxis. Jérémie Palacci et al (2015), Science Advances http://dx.doi.org/10....
published: 10 May 2015
Artificial rheotaxis
Artificial rheotaxis
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1:29
Rheotaxis Training For The Fight With Todd Hays
Todd Hays is a coward, I don't even know why i'm training for him, its an easy win if he e...
published: 23 Jun 2013
Rheotaxis Training For The Fight With Todd Hays
Rheotaxis Training For The Fight With Todd Hays
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Rheotaxis - Soul Collector...
Rheotaxis-welcome to room 666...
Human sperm rheotaxis: a passive physical process...
Artificial rheotaxis...
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photo: AP / James Allan
Tourist describes death, harrowing month in New Zealand bush
Edit US News 26 Aug 2016
Czech tourist Pavlina Pizova has described the death of her partner and the month she spent in the New Zealand wilderness after the couple set out on an ill-fated hike ... ....
photo: AP / STR, File
Philippines Kills 11 Abu Sayyaf Militants After Beheading
Edit ABC News 26 Aug 2016
Philippine troops have killed 11 Abu Sayyaf militants, including an influential commander, in an assault on the extremists following their beheading of a captive over an unpaid ransom ... ....
photo: AP / Aleppo Media Center via AP
Is Syria And Libya The New Face Of Political Genocide?
Edit WorldNews.com 26 Aug 2016
Article by WN.com Correspondent Dallas DarlingWith news President Barack Obama used a 15-year-old piece of legislation approved by Congress to militarily intervene in, and aggressively bomb, 14 countries, the most recent being Syria and Libya, it appears the new face of genocide is politically motivated ... In other words, everyone cannot exploit everyone else at the same time ... 11 attacks ... by the corporate dominated news media ... 4 ... 5 ... 4.....
photo: Creative Commons / Gage Skidmore
Hillary Clinton is Spreading Islamist Extremism
Edit Dissident Voice 26 Aug 2016
If the West in general, and the United States in particular, left the Arab and Muslim world alone and in peace, we would most likely never see all those terrorist attacks, which are rocking the world from Indonesia to France. There would be no Mujahedeen and its mutation into al-Qaida; in Afghanistan or elsewhere. There would be no traces of the ISIS (or ISIL or I.S ... Part of the Saudi Royal mafia ... We don’t recognize it, anymore ... Correct....
photo: AP / Borg Wong
US Navy ship fires warning shots at Iranian vessel
Edit Eye Witness News 26 Aug 2016« back to news headlines
Bimodal rheotactic behavior reflects flagellar beat asymmetry in human sperm cells
Edit PNAS 10 Dec 2015
Abstract. Rheotaxis, the directed response to fluid velocity gradients, has been shown to facilitate stable upstream swimming of mammalian sperm cells along solid surfaces, suggesting a robust physical mechanism for long-distance navigation during fertilization ... These results challenge current theoretical models of sperm locomotion. ....
Penn Researchers Answer Question about Nematode Behavior: Nature, Nurture, or Physics? (University of Pennsylvania)
Edit Public Technologies 06 Jul 2015
The origins of this upstream swimming behavior, also known as "positive rheotaxis," is an open question, but understanding it is critical to the way high-throughput experiments with the organism are run ... In other words, Yuan found that rheotaxis is a passive behavior, independent of genotype ... "This rheotaxis mechanism," Yuan said, ......
Propensity of undulatory swimmers, such as worms, to go against the flow
Edit PNAS 05 Mar 2015
One such orientation behavior is the alignment of aquatic organisms with (negative rheotaxis) or against (positive rheotaxis) fluid current. The questions of whether low-Reynolds-number, undulatory swimmers, such as worms, rheotax and whether rheotaxis is a deliberate or an involuntary response to mechanical forces have been the subject of conflicting reports....
Sperm spiralling to the egg
Edit Medium 14 Jan 2015
Sperm swim through channels with a spiral motion, which may help them find the egg. A sperm cell must complete a long and taxing journey to stand a chance of fertilising an egg cell. This quest covers a distance that is thousands of times longer than the length of a sperm cell ... The fluids that the sperm cells travel through are not static ... “Rheotaxis facilitates upstream navigation of mammalian sperm cells” (May 27, 2014) ... Published in ... ....
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