- Mar 2021
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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S. Y. Oh, et al., ACS Appl. Mater. Interfaces 10, 13729–13740
To add on wearable skin electronics, the created sweat glucose and pH sensors. The sensors were created out of carbon nanotubes combined with different polymers.
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G. Schwartz, et al., Nat. Commun. 4, 1859
They have created a flexible pressure sensor which has the capability of non-invasive continuous radial artery pule monitoring. It is stated that this has the capability of being a breakthrough for wearable cardiovascular health monitoring.
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H. C. Ko, et al., Nature 454, 748–753
They created an hemispherical optoelectronic device that can replicate the functions and characteristics of a human eye such as a wide field of view and low aberrations. This electronic device is based off of single-crystalline silicon and is compressible, which enables the hemispherical shape.
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S. Choi, et al., Nat. Nanotechnol. 13, 1048–1056
Here, biocompatable and stretchable materials were tested for implant use. Gold coated silver nanowires within a polymer were tested to see its conductivity. Using this material they were able to fabricate wearable and implantable soft bioelectronic devices that can be conformally integrated with human skin.
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J. A. Rogers, T. Someya, Y. Huang. Science 327, 1603–1607
They reviewed materials that maintain proper electronic properties while having the ability to be stretched, compressed, twisted, bent, and deformed. They discussed different applications for these technologies and possible commercialization.
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T. Sekitani, et al.,Science 326, 1516–1519 (2009)
They used transistors with a floating gate embedded in hybrid dielectrics at a nanoscale of size, and created a flexible array of these floating gate transistors. They coupled this with a pressure sensitive rubber sheet, and the result was a matrix that was able to read mechanical pressure and store it as an image.
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C. Choi, et al., Nat. Commun. 8,
They test a high density, hemispherical image sensor array comprised of an atomically small MoS2 heterostructure that has the capability of releasing strain. They deem this device to be capable of being a soft retinal implant capable of various imaging elements.
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I. R. Minev, et al., Science 347, 159–163 (2015).
Stiff-neural implants have very rare compatibility with soft-neural tissues. Therefore an soft-neural implant was configured that is elastic like dura matter (the protective membrane of the spinal cord).
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Y. M. Song, Yet al., Nature 497
An elastomeric camera was created in the likeness of ant and beetle eyes. These cameras have close to full hemispherical shapes, at around 160 degrees. This hopes to copy arthropods who have wide-angle field of view, low aberrations, high acuity to motion and an infinite depth of field which are all difficult to replicate.
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1. W. Gao, et al., Nature 529, 509–514 (2016).
A self-healing system was created that was capable of automatically repair damage from repeating events. They used a coating-substrate (a substance on which an enzyme acts) to deliver healing agents to cracks within the polymer.
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S. Xu, et al., Science 344, 70–74 (2014).
They created a thin, comfortable device that can be laminated or stuck to the skin of a person to allow for the monitoring of physiological monitoring for the user. Examples of this could be heart rate or blood pressure. This is also a wireless device.
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D. H. Kim, et al., Nat. Mater
A non-invasive ultra-thin electronic interface was created what is capable of being mounted on tissue using a a protein called fibroin which can be obtained from silk. This protein is capable of being absorbed back into the tissue which results in the mounting of the device. These electronics are capable of neural mapping of the brain.
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X. Yu, et al., Nature 575, 473–479 (2019).
They created a wireless, battery free, touch based electronic system that is capable of being placed onto the skin. This technology has the capability of communicating information through vibrations. They also have the capability of being used for VR.
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Y. Chen, A. M. Kushner, G. A. Williams, Z. Guan, Nat. Chem
A multiple phase heat sensitive rubber like material was created. This substance is extremely tough and durable while also having the capability of self-healing.
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D.-H. Kim, et al., Science 320, 507–511 (2008).
An easily foldable and stretchable circuit was created using silicon, a good semi-conductive metal. They combined the silicon with rubber like plastic material to help create the flexibility of the circuit.
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- Feb 2021
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis
A flexible sensor device was created with the ability to analyze different elements/compounds found within sweat such as glucose and sodium while also monitoring skin temperature. All of this is fully integrated within the system so no outside analysis is needed.
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- Feb 2020
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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(http://aa.usno.navy.mil/data/docs/MoonFraction.php)
This link does not seem to work, but the data resources of the United States Naval Observatory Astronomical Applications Department can be found at this website.
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- Dec 2017
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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followed by failure to interbreed when partial connection between the oceans was reestablished
Because of the long separation from one another, when some connection was established between either sides of the Isthmus, the shrimp pairs no longer had preferences to each other. Their extended sexual isolation probably had them adapted into altering their breeding behavior. ~J.D.A.
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Hence, pairs P5-C5 and P6-C6 probably separated during the period of marked shoaling and environmental divergence preceding final closure.
P5-P6 pair were isolated from each other just before the final closing of the Panama seaway. This was due to shoaling of water and the environmental change that came with it. ~S.Z.
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1. E. Mayr, Animal Species and Evolution (Harvard Univ. Press, Cambridge, 1963).
This paper contains discussion of species concepts and their application, morphological species characters and sibling species, biological properties of species, isolating mechanisms, hybridization, the variation and genetics of populations, storage and protection of genetic variation, the unity of the genotype, geographic variation, the polytypic species of the taxonomist, the population structure of species, kinds of species, multiplication of species, geographic speciation, the genetics of speciation, the ecology of speciation, and species and transpecific evolution. All of which can contribute a great deal to the topic of this paper. ~S.Z.
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D. S. Jordan, Am. Nat. 42, 73 (1908)
Supports that a physical barrier will increase the chances of divergence between species creating two or more sub-species decedents . ~S.Z.
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J. A. Coyne and H. A. Orr, Evolution 43, 362 (1989). W. R. Rice, ibid., p. 223.
The authors performed a similarly designed experiment to the one cited here which was done on drosophila (flies). This is to show that there are other species that have undergone staggered isolation through similar or even different events. (DV)
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D. L. Swofford, PAUP: Phylogenetic Analysis Using Parsimony, version 3.1; (Illinois Natural History Survey, Champaign, IL, 1993).
The authors used this source as a bases to analyze the snapping shrimps mitochondrial DNA data and arrange the organisms in a phylogenetic tree as seen in figure 1. (DV)
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J. H. Gillespie, The Causes of Molecular Evolution (Oxford Univ. Press, New York, 1991).
The authors site this book as they are referring to the importance of having and maintaining genetic variation within a population. Also they might have utilized the mathematical theory of selection in a fluctuating environments, since the paper focuses on environmental and geographical changes affects on isolation. (DV)
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Genetic divergence before final closure may have been facilitated by changing oceanographic conditions
Genetic divergence was observed to have occured at different moments when oceanic changes like the haulting of certain currents across the Panama seaway and the shallowing of certain areas. (DV)
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- Nov 2017
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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Long-term nutrient enrichment decouples predator and prey production
This article discusses the effect the addition of nutrients has on an aquatic ecosystem. Originally the author hypothesized an increase of energy transfer from prey to predators because of the increase of nutrients. However, this did not occur because the increase in nutrient led to an increase of predator resistant prey.
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Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter
This article discusses how an increase in nutrients affects the levels of coarse and fine organic litter. It was observed that there were higher levels of fine organic material which led to an increase in bacteria. However, in the stream with no nutrients added to it, there was an increase in both fungal and bacterial communities.
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Nutrient enrichment alters storage and fluxes of detritus in a headwater stream ecosystem
This article demonstrates how the addition of nitrogen and phosphorus led to an increase in the production of fine organic compound by more than 300%. The article also mentions that this increase in fine organic compound will have an effect on the entire ecosystem in that area in the long term.
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Multiple trophic levels of a forest stream linked to terrestrial litter inputs
This article discusses the importance of terrestrial litter on an aquatic ecosystem. It was observed that organisms that lived in the stream that was being tested were affected the most by the absence of litter and the same effects could be observed throughout the entire ecosystem. However, terrestrial fauna was not affected meaning that it got its carbon from another source.
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Lakes and reservoirs as regulators of carbon cycling and climate.
This article mentions the that the rate at which inland water sources release carbon dioxide is equivalent to the rate at which carbon is absorbed by the ocean. Methane is also being release in higher levels from lakes which are beginning to thaw because of increasing temperatures from global warming.
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Continental-scale effects of nutrient pollution on stream ecosystem functioning
This experiment was a pan-European research of more than 100 streams in multiple European countries. It helped determine the importance of litter breakdown and states that countries should begin to consider the importance of regulating nutrient levels in aquatic ecosystems.
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Ecosystem metabolism and turnover of organic carbon along a blackwater river continuum
This article discusses the respiration rate of an aquatic ecosystem and uses it to determine patterns of activity found within a river during different seasons. It was observed that there were higher levels of respiration when there were was more organic carbon in the river.
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Nutrient co-limitation of primary producer communities
This article focuses on how nutrients affect the growth of primary producers. The factors that were observed to have the highest effects on the ecosystems were nitrogen and phosphorus levels.
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Whole-system nutrient enrichment increases secondary production in a detritus-based ecosystem
This article discusses how the addition of nutrients in an aquatic ecosystem affects secondary production. It was noted that there was an increase in secondary consumers most likely caused because of an increase in prey. There was also an increase of secondary consumer predators. It is mentioned that the increase of nutrients in the two years the survey was done resulted in positive effects for the secondary consumers, however, this might eventually change as the carbon levels in the ecosystem begin to decline because of the higher nutrient levels.
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Human influences on nitrogen removal in lakes
This article discusses how human practices have led to a increase of nitrogen levels in lakes. The article also mentions that an increase of phosphorus in lakes resulted in the extraction of higher levels of nitrogen. However, the author also states that laws pertaining to the concentration of phosphorus in aquatic habitats should not be removed or relaxed because phosphorus can also have a negative effect on an ecosystem if found in high concentrations.
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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Min, K.-T. and Benzer, S. (1997). Wolbachia, normally a symbiont of Drosophila, can be virulent, causing degeneration and early death. Proc. Natl. Acad. Sci. USA 94, 10792-10796.
Camacho, Oliva, and Serbus explain the relevance of parasitic Wolbachia being detrimental to the growth and oocyte growth of the Drosophila.
GG
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Teixeira, L., Ferreira, A. and Ashburner, M. (2008). The bacterial symbiont Wolbachia induces resistance to RNA viral infections in Drosophila melanogaster. PLoS Biol. 6, e2.
The information presented in this paper explores how the information presented by Camacho, Oliva, and Serbus is relevant. It states that according to the endosymbitic behavior of Wolbachia, the susceptibility of the host organism to viral RNA infections may be diminished due to the resistance of Wolbachia to those viral RNA infections.
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Ponton, F., Wilson, K., Holmes, A., Raubenheimer, D., Robinson, K. L. and Simpson, S. J. (2015). Macronutrients mediate the functional relationship between Drosophila and Wolbachia. Proc. Biol. Sci. 282, 20142029.
Camacho, Oliva, and Serbus demonstrate how macronutrients mediate the functional relationship between Drosophila and Wolbachia, by using sucrose and its dietary variants to create an environment allowing the Drosophila to thrive and the Wolbachia to proliferate within the Drosophila.
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Serbus, L. R., White, P. M., Silva, J. P., Rabe, A., Teixeira, L., Albertson, R. and Sullivan, W. (2015). The impact of host diet on Wolbachia titer in Drosophila. PLoS Pathog. 11, e1004777.
Camacho, Oliva, and Serbus used a previously published article from Serbus to delve into the specifics of how the host diet impacts Wolbachia titer.
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Mouton, L., Henri, H., Charif, D., Bouletreau, M. and Vavre, F. (2007). Interaction between host genotype and environmental conditions affects bacterial density in Wolbachia symbiosis. Biol. Lett. 3, 210-213. Musselman, L. P., Fink, J. L., Narzinski, K., Ramachandran, P. V., Hathiramani, S. S., Cagan, R. L. and Baranski, T. J. (2011). A high-sugar diet produces obesity and insulin resistance in wild-type Drosophila. Dis. Model. Mech. 4, 842-849.
Camacho, Oliva, and Serbus further explored how the Wolbachia titer increased depending on the type of sugar product fed to the Drosophila.
GG
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Wang, M. and Wang, C. (1993). Characterization of glucose transport system in Drosophila Kc cells. FEBS Lett. 317,241-244.
Camacho, Oliva, and Serbus used the knowledge presented in this article to maximize the efficacy of the consumption of the varied glucose by Drosophila.
GG
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Dale, C. and Moran, N. A. (2006). Molecular interactions between bacterial symbionts and their hosts. Cell 126, 453-465
While Camacho, Oliva, and Serbus specified which interactions between bacterial symbionts and their hosts. The mechanism by which this interaction occurs is still unclear.
GG
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Christensen, S., Pérez Dulzaides, R., Hedrick, V. E., Momtaz, A. J. M. Z., Nakayasu, E. S., Paul, L. N. and Serbus, L. R. (2016). Wolbachia endosymbionts modify Drosophila ovary protein levels in a context-dependent manner. Appl. Environ. Microbiol. 82, 5354-5363
Camacho, Oliva, and Serbus further explore a topic primarily researched by Serbus on how Drosophilaovaries are modified by Wolbachia.
GG
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Bordenstein, S. R. and Bordenstein, S. R. (2011). Temperature affects the tripartite interactions between bacteriophage WO, Wolbachia, and cytoplasmic incompatibility. PLoS ONE 6, e29106. Boyle, L., O'Neill, S. L., Robertson, H. M. and Karr, T. L. (1993). Interspecific and intraspecific horizontal transfer of Wolbachia in Drosophila. Science 260, 1796-1799.
Camacho, Oliva, and Serbus review the contributions made by authors regarding the transfer and survival/ compatibility of Wolbachia in various environments.
Camacho, Oliva, and Serbus further investigate the effects of Wolbachia on Drosophila in a high or low sucrose concentrated environment.
GG
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Caragata, E. P., Rancès, E., Hedges, L. M., Gofton, A. W., Johnson, K. N., O'Neill, S. L. and McGraw, E. A. (2013).Dietary cholesterol modulates pathogen blocking by Wolbachia. PLoS Pathog. 9, e1003459.
Camacho, Oliva, and Serbus reviewed articles that explored how cholesterol affects Wolbachia, while further questioning how this may improve the overall pathogenic blocking capabilities of their host.
GG
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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D. S. Jordan, Am. Nat. 42, 73 (1908)
Supports that a physical barrier will increase the chances of divergence between species creating two or more sub-species decedents . ~S.Z.
-
E. Mayr, Animal Species and Evolution (Harvard Univ. Press, Cambridge, 1963).
This paper contains discussion of species concepts and their application, morphological species characters and sibling species, biological properties of species, isolating mechanisms, hybridization, the variation and genetics of populations, storage and protection of genetic variation, the unity of the genotype, geographic variation, the polytypic species of the taxonomist, the population structure of species, kinds of species, multiplication of species, geographic speciation, the genetics of speciation, the ecology of speciation, and species and transpecific evolution. All of which can contribute a great deal to the topic of this paper. ~S.Z.
-
Hence, pairs P5-C5 and P6-C6 probably separated during the period of marked shoaling and environmental divergence preceding final closure.
P5-P6 pair were isolated from each other just before the final closing of the Panama seaway. This was due to shoaling of water and the environmental change that came with it. ~S.Z.
-
followed by failure to interbreed when partial connection between the oceans was reestablished
Because of the long separation from one another, when some connection was established between either sides of the Isthmus, the shrimp pairs no longer had preferences to each other. Their extended sexual isolation probably had them adapted into altering their breeding behavior. ~J.D.A.
-
J. A. Coyne and H. A. Orr, Evolution 43, 362 (1989). W. R. Rice, ibid., p. 223.
The authors performed a similarly designed experiment to the one cited here which was done on drosophila (flies). This is to show that there are other species that have undergone staggered isolation through similar or even different events. (DV)
-
D. L. Swofford, PAUP: Phylogenetic Analysis Using Parsimony, version 3.1; (Illinois Natural History Survey, Champaign, IL, 1993).
The authors used this source as a bases to analyze the snapping shrimps mitochondrial DNA data and arrange the organisms in a phylogenetic tree as seen in figure 1. (DV)
-
J. H. Gillespie, The Causes of Molecular Evolution (Oxford Univ. Press, New York, 1991).
The authors site this book as they are referring to the importance of having and maintaining genetic variation within a population. Also they might have utilized the mathematical theory of selection in a fluctuating environments, since the paper focuses on environmental and geographical changes affects on isolation. (DV)
-
Genetic divergence before final closure may have been facilitated by changing oceanographic conditions
Genetic divergence was observed to have occured at different moments when oceanic changes like the haulting of certain currents across the Panama seaway and the shallowing of certain areas. (DV)
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- Oct 2017
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www.scienceintheclassroom.org www.scienceintheclassroom.org
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M. Nei, Genetics 89, 583 (1978)
Nei found the average heterozygosity and genetic distance from a small number of individuals.This paper explains how biases arise in calculations when small samples are used. However, this paper establishes an average that reduces bias. (JP)
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R. W. Rubinoff and 1. Rubinoff, Evolution 25, 88 (1971)
This paper, through studying 3 different species of Bathygobius, found that morphological divergence is not correlated with reproductive isolation. Their experiment was testing the extent in which these 3 species had evolved reproductive isolation in the Isthmus of Panama. (JP)
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4. E. Bermingham and H. A. Lessios, Proc. Nati. Acad. Sci. U.S.A. 90, 2734 (1993).
This source demonstrates that mitochondrial DNA is able to provide fairly accurate estimates of times since separation of a species in a 3 million year range. Here they also used organisms from the Isthmus of Panama and gel electrophoresis to deduce the time of speciation. (JP)
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A. T. Vawter, R. Rosenblatt, G. C. Gorman, Evolution 34, 705 (1980)
The authors of this paper found that, through parsimony analysis of the sequence divergence estimates and of sequence polymorphisms of the Holarctic fish's mtDNA, different Holarctic fish species arose from a geographical event that occurred during the beginning of the mid-Pliocene period.
The authors of this paper cited this source because this source conducts a similar study in deducing a time frame in which speciation of the Holarctic fish occurred. (JP)
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H. A. Lessios, Nature 280, 599 (1979)
This source published in 1979 to Nature tests the reliability of the molecular clock hypothesis by using Panamanian sea urchins. The author argues that the molecular clock hypothesis is not tenable or supportable. (JP)
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- Aug 2015
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scienceintheclassroom.org scienceintheclassroom.org
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H. Wang, M. A. Winnik, I. Manners, Synthesis and self-assembly of poly(ferrocenyldimethylsilane- b -2-vinylpyridine) diblock copolymers. Macromolecules 40, 3784 (2007).
In this paper, the authors developed a new class of diblock copolymers that have a metal-containing hydrophobic block (PFS) and an organic hydrophilic block (P2VP): PFS = poly(ferrocenyldimethylsilane) and P2VP = poly(2-vinylpyridine). The authors of this publication discovered the ability to obtain spherical and cylindrical morphologies simply by using different alcohols. Having established the ability to obtain cylindrical micelles using the PFS-b-P2VP block copolymer system in isopropyl alcohol, the authors modified their approach in the current study to obtain supermicelles.
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P. A. Rupar, G. Cambridge, M. A. Winnik, I. Manners, Reversible cross-linking of polyisoprene coronas in micelles, block comicelles, and hierarchical micelle architectures using Pt(0)–olefin coordination. J. Am. Chem. Soc. 133, 16947 (2011).
This paper established that Karstedt's catalysts ability to cross-link the double bonds in polyisoprene in the absences of silicon-containing molecules. Besides acquiring a variety of morphologies, the authors also investigated their ability to use Karstedt's catalyst to synthesize reversible polymer gel networks.
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X. S. Wanget al., Shell-cross-linked cylindrical polyisoprene- b -polyferrocenylsilane (PI- b -PFS) block copolymer micelles: One-dimensional (1D) organometallic nanocylinders. J. Am. Chem. Soc. 129, 5630 (2007).
This reference investigates the development of 1D nano-structures through the use of cross-linked cylindrical micelles. This paper highlights possible applications for these 1D nanomaterials such as microfluidics.
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R. K. O’Reilly, C. J. Hawker, K. L. Wooley, Cross-linked block copolymer micelles: functional nanostructures of great potential and versatility. Chem. Soc. Rev. 35, 1068 (2006).
This review paper describes the uses and progress made in the field of cross-linked micelles. Concepts covered include stabilization as well chemical modification and functionalization.
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W. Zhanget al., Supramolecular linear heterojunction composed of graphite-like semiconducting nanotubular segments. Science 334, 340 (2011).
References: This paper describes the synthesis of semiconducting nanotubes through a process similar to CDSA by connecting dissimilar junctions, referred to as heterojuntions, to study the behaviors of photocarriers.
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Z.-X. Du, J.-T. Xu, Z.-Q. Fan, Micellar morphologies of poly(ε-caprolactone)- b -poly(ethylene oxide) block copolymers in water with a crystalline core. Macromolecules 40, 7633 (2007).
This paper describes the use of a biodegradable polymer in order to obtain a variety of micelle morphologies. A concept referred to as tethering density is used in this paper to explain unexpected morphologies.
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Schmelz, M. Karg, T. Hellweg, H. Schmalz, General pathway toward crystalline-core micelles with tunable morphology and corona segregation. ACS Nano 5, 9523 (2011).
This paper uses triblock copolymers to synthesize cylindrical and spherical micelles. By carefully controlling crystallization, the authors were able to control the micellar morphology in a highly selective fashion.
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T. Gädt, N. S. Ieong, G. Cambridge, M. A. Winnik, I. Manners, Complex and hierarchical micelle architectures from diblock copolymers using living, crystallization-driven polymerizations. Nat. Mater. 8, 144 (2009).
This paper utilizes CDSA to synthesize noncylindrical block co-micelles. The authors utilized plateletlike micelle and cylindrical micelles in order to form scarflike architectures using platelet-cylindrical and cylindrical-cylindrical connections.
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X. S. Wanget al., Cylindrical block copolymer micelles and co-micelles of controlled length and architecture. Science 317, 644 (2007)
This paper describes the discovery of CDSA. The authors draw a comparison to living polymerization and explain the phenomenon of epitaxial crystallization-induced co-micellization
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Y. Xia, B. D. Olsen, J. A. Kornfield, R. H. Grubbs, Efficient synthesis of narrowly dispersed brush copolymers and study of their assemblies: The importance of side chain arrangement. J. Am. Chem. Soc. 131, 18525 (2009).
This reference describes the synthesis of brush block and random copolymers. The polymers are referred to as a "brush" because pendant groups are dangling off the main chain. The brush polymers synthesized were amphiphilic and demonstrated self-assembly.
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Walther, M. Drechsler, A. H. E. Müller, Structures of amphiphilic Janus discs in aqueous media. Soft Matter 5, 385 (2009).
This paper describes the synthesis of amphiphilic Janus discs using a block terpolymer (three distinct blocks comprised of three distinct monomers). Two different size discs were made where, depending on size, the manner in which the hydrophobic side is "protected" from water can vary. The smaller discs are stabilized by the long hydrophilic polymer chains, protruding out of one side and shielding the hydrophobic side against water. The larger discs undergo aggregation as well as bending to again shield the hydrophobic side from the water by flipping over one part of the structure.
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J. Dupont, G. Liu, ABC triblock copolymer hamburger-like micelles, segmented cylinders, and Janus particles. Soft Matter 6, 3654 (2010).
This reference is an example where triblock copolymers were photo-crosslinked to create Janus particles which were classified as "hamburger-like" micelles.
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Walther, A. H. E. Müller, Janus particles. Soft Matter 4, 663 (2008)
This review paper discusses a class of noncentrosymmetric nanoparticles referred to as the Janus particle. These particles are rather challenging to synthesize because two different chemistries are present on the surface of the particle.
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H. Cui, Z. Chen, S. Zhong, K. L. Wooley, D. J. Pochan, Block copolymer assembly via kinetic control. Science 317, 647 (2007).
This paper utilized charged polymers as well as metal cations and a variety of solvents to kinetically trap unique micelle morphologies. The self-assembly systems were forced down a specific pathway in order to form morphologies that would not have typically occurred without assistance.
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L. Zhang, A. Eisenberg, Multiple morphologies of “crew-cut” aggregates of polystyrene-b-poly(acrylic acid) block copolymers. Science 268, 1728 (1995).
This paper was one of the first papers to establish the ability to form micelles of different morphologies (beyond just spherical) for systems using amphiphilic block copolymers
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- Jul 2015
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www.sciencemag.org www.sciencemag.org
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J. F. Soderholm, S. L. Bird, P. Kalab, Y. Sampathkumar, K. Hasegawa, M. Uehara-Bingen, K. Weis, R. Heald, Importazole, a small molecule inhibitor of the transport receptor importin-β. ACS Chem. Biol. 6, 700–708 (2011).
Importazole is a small molecule inhibitor of the transport receptor importin-β. This inhibitor was identified by a screening assay developed by the authors of this paper.
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A. J. Firestone, J. S. Weinger, M. Maldonado, K. Barlan, L. D. Langston, M. O’Donnell, V. I. Gelfand, T. M. Kapoor, J. K. Chen, Small-molecule inhibitors of the AAA+ ATPase motor cytoplasmic dynein. Nature 484, 125–129 (2012). doi:10.1038/nature10936 pmid:22425997
This work reported the discovery of ciliobrevins, the first specific small-molecule antagonists of cytoplasmic dynein.
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K. V. Butler, J. Kalin, C. Brochier, G. Vistoli, B. Langley, A. P. Kozikowski, Rational design and simple chemistry yield a superior, neuroprotective HDAC6 inhibitor, tubastatin A. J. Am. Chem. Soc. 132, 10842–10846 (2010). doi:10.1021/ja102758v pmid:20614936
This paper reported the development of Tubastatin A, a potent and selective HDAC6 inhibitor.
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H. Ouyang, Y. O. Ali, M. Ravichandran, A. Dong, W. Qiu, F. MacKenzie, S. Dhe-Paganon, C. H. Arrowsmith, R. G. Zhai, Protein aggregates are recruited to aggresome by histone deacetylase 6 via unanchored ubiquitin C termini. J. Biol. Chem. 287, 2317–2327 (2012).
This work suggested a novel ubiquitin-mediated signaling pathway, where the exposure of ubiquitin C termini within protein aggregates enables HDAC6 recognition and transport to the aggresome. The authors found that the ubiquitin-binding domain (ZnF-UBP) of HDAC6, instead of recognizing protein aggregates by binding directly to polyubiquitinated proteins, binds exclusively to the unanchored C-terminal diglycine motif of ubiquitin.
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Y. Zhang, B. Gilquin, S. Khochbin, P. Matthias, Two catalytic domains are required for protein deacetylation. J. Biol. Chem. 281, 2401–2404 (2006).
In this report, the authors showed that both HDAC domains are required for the intact deacetylase activity of HDAC-6.
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Y. Zhang, S. Kwon, T. Yamaguchi, F. Cubizolles, S. Rousseaux, M. Kneissel, C. Cao, N. Li, H. L. Cheng, K. Chua, D. Lombard, A. Mizeracki, G. Matthias, F. W. Alt, S. Khochbin, P. Matthias, Mice lacking histone deacetylase 6 have hyperacetylated tubulin but are viable and develop normally. Mol. Cell. Biol. 28, 1688–1701 (2008). doi:10.1128/MCB.01154-06 pmid:18180281
In this study, the author generated HDAC6 knock out mice and investigated the in vivo functions of HDAC6 and the relevance of tubulin acetylation/deacetylation. they observed that HDAC6-deficient mice are viable and fertile and show hyperacetylated tubulin in most tissues.They concluded that mice survive well without HDAC6 and that tubulin hyperacetylation is not detrimental to normal mammalian development.
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I. Kemler, G. Whittaker, A. Helenius, Nuclear import of microinjected influenza virus ribonucleoproteins. Virology 202, 1028–1033 (1994).
This work showed that when influenza virus ribonucleoproteins (vRNPs), devoid of M1, were introduced into the cytoplasm of cells by microinjection, they were found to be imported into the nucleus, and the RNA was transcribed. Their uptake into the nucleus was ATP-dependent, inhibited by antibodies to the nuclear pore complex, unaffected by the prior acidification of the vRNPs, and not inhibited by an anti-virurs, called amantadine. These experiments demonstrated that for productive infection, all the early stages of the viral entry pathway can be bypassed.
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anerjee, Y. Yamauchi, A. Helenius, P. Horvath, High-content analysis of sequential events during the early phase of influenza A virus infection. PLOS ONE 8, e68450 (2013).
This study provides a powerful high-throughput platform to understand the host cell processes. The authors developed quantitative, imaging-based assays to dissect seven consecutive steps in the early phases of IAV infection in tissue culture cells.
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K. S. Matlin, H. Reggio, A. Helenius, K. Simons, Infectious entry pathway of influenza virus in a canine kidney cell line. J. Cell Biol. 91, 601–613 (1981).
This work investigated the cell fusion process of representatives of 3 families of enveloped viruses. it was discovered that hemagglutinin plays a role for the influenza in the low-pH-dependent membrane fusion activity. Low-pH-induced fusion is a widespread property of enveloped animal viruses and that it may play a role in the infective process.
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L. H. Pinto, L. J. Holsinger, R. A. Lamb, Influenza virus M2 protein has ion channel activity. Cell 69, 517–528 (1992).
The authors of this paper identified the ion channel activity of M2.
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J. White, K. Matlin, A. Helenius, Cell fusion by Semliki Forest, influenza, and vesicular stomatitis viruses. J. Cell Biol. 89, 674–679 (1981).
This work investigated the cell fusion process of representatives of 3 families of enveloped viruses. it was discovered that hemagglutinin plays a role for the influenza in the low-pH-dependent membrane fusion activity. Low-pH-induced fusion is a widespread property of enveloped animal viruses and that it may play a role in the infective process.
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K. Martin, A. Helenius, Nuclear transport of influenza virus ribonucleoproteins: The viral matrix protein (M1) promotes export and inhibits import. Cell 67, 117–130 (1991). doi:10.1016/0092-8674(91)90576-K pmid:1913813
This work described the nuclear transport of influenza virus ribonucleoproteins (vRNPs). Viral matrix protein (M1) associates with newly assembled vRNPs in the nucleus and escorts them to the cytoplasm through the nuclear pores. In contrast, during entry of the virus into a new host cell, M1 protein dissociates from the RNPs, allowing them to enter the nucleus.
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www.sciencemag.org www.sciencemag.org
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G. Larson, J. Burger,Trends Genet.29, 197–205 (2013).
This study is about animal domestication. It explains that the dog is the only animal domesticated before the advent of agriculture. It also discuss the limits of mtDNA analysis.
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