26 August 2015

Chemistry report on atoms

use this article :
This article presents an activity that focuses on helping students investigate the formation of rocks, minerals, and gemstones. Students describe visual, textual, and physical properties of various specimens of minerals. Using compare and contrast skills, students can classify the primary types of rock, ask questions about the Earth's inner processes that result in the formation of our natural resources, and discuss cross-cultural traditions' perspectives on many of our Earth's natural resources. In this multicultural science activity, children actively engage in a hands-on lesson that allows them to visualize and appreciate the beauty of the Earth's natural resources through the art of jewelry making. This lesson provides an artistic approach to science as students explore various properties of the Earth's materials and physical properties of matter. [PUBLICATION ABSTRACT]
and this article:
Nature builds flawless diamonds, sapphires and other gems. Now a Northwestern University research team is the first to build near-perfect single crystals out of nanoparticles and DNA, using the same structure favored by nature.

“Single crystals are the backbone of many things we rely on — diamonds for beauty as well as industrial applications, sapphires for lasers and silicon for electronics,” said nanoscientist Chad A. Mirkin. “The precise placement of atoms within a well-defined lattice defines these high-quality crystals.

“Now we can do the same with nanomaterials and DNA, the blueprint of life,” Mirkin said. “Our method could lead to novel technologies and even enable new industries, much as the ability to grow silicon in perfect crystalline arrangements made possible the multibillion-dollar semiconductor industry.”

His research group developed the “recipe” for using nanomaterials as atoms, DNA as bonds and a little heat to form tiny crystals. This single-crystal recipe builds on superlattice techniques Mirkin's lab has been developing for nearly two decades.
In this recent work, Mirkin, an experimentalist, teamed up with Monica Olvera de la Cruz, a theoretician, to evaluate the new technique and develop an understanding of it. Given a set of nanoparticles and a specific type of DNA, Olvera de la Cruz showed they can accurately predict the 3-D structure, or crystal shape, into which the disordered components will self-assemble.

Mirkin is the George B. Rathmann Professor of Chemistry in the Weinberg College of Arts and Sciences. Olvera de la Cruz is a Lawyer Taylor Professor and professor of materials science and engineering in the McCormick School of Engineering and Applied Science. The two are senior co-authors of the study.

The results will be published Nov. 27 in the journal Nature.

The general set of instructions gives researchers unprecedented control over the type and shape of crystals they can build. The Northwestern team worked with gold nanoparticles, but the recipe can be applied to a variety of materials, with potential applications in the fields of materials science, photonics, electronics and catalysis.

A single crystal has order: its crystal lattice is continuous and unbroken throughout. The absence of defects in the material can give these crystals unique mechanical, optical and electrical properties, making them very desirable.

In the Northwestern study, strands of complementary DNA act as bonds between disordered gold nanoparticles, transforming them into an orderly crystal. The researchers determined that the ratio of the DNA linker's length to the size of the nanoparticle is critical.

“If you get the right ratio it makes a perfect crystal — isn't that fun?” said Olvera de la Cruz, who also is a professor of chemistry in the Weinberg College of Arts and Sciences. “That's the fascinating thing, that you have to have the right ratio. We are learning so many rules for calculating things that other people cannot compute in atoms, in atomic crystals.” 

The ratio affects the energy of the faces of the crystals, which determines the final crystal shape. Ratios that don't follow the recipe lead to large fluctuations in energy and result in a sphere, not a faceted crystal, she explained. With the correct ratio, the energies fluctuate less and result in a crystal every time.

“Imagine having a million balls of two colors, some red, some blue, in a container, and you try shaking them until you get alternating red and blue balls,” Mirkin explained. “It will never happen.

“But if you attach DNA that is complementary to nanoparticles — the red has one kind of DNA, say, the blue its complement — and now you shake, or in our case, just stir in water, all the particles will find one another and link together,” he said. “They beautifully assemble into a three-dimensional crystal that we predicted computationally and realized experimentally.”

To achieve a self-assembling single crystal in the lab, the research team reports taking two sets of gold nanoparticles outfitted with complementary DNA linker strands. Working with approximately 1 million nanoparticles in water, they heated the solution to a temperature just above the DNA linkers' melting point and then slowly cooled the solution to room temperature, which took two or three days.

The very slow cooling process encouraged the single-stranded DNA to find its complement, resulting in a high-quality single crystal approximately three microns wide. “The process gives the system enough time and energy for all the particles to arrange themselves and find the spots they should be in,” Mirkin said.

The researchers determined that the length of DNA connected to each gold nanoparticle can't be much longer than the size of the nanoparticle. In the study, the gold nanoparticles varied from five to 20 nanometers in diameter; for each, the DNA length that led to crystal formation was about 18 base pairs and six single-base “sticky ends.”

“There's no reason we can't grow extraordinarily large single crystals in the future using modifications of our technique,” said Mirkin, who also is a professor of medicine, chemical and biological engineering, biomedical engineering and materials science and engineering and director of Northwestern's International Institute for Nanotechnology.

The title of the paper is “DNA-mediated nanoparticle crystallization into Wulff polyhedra.”

In addition to Mirkin and Olvera de la Cruz, authors of the paper are Evelyn Auyeung (first author), Ting I. N. G. Li, Andrew J. Senesi, Abrin L. Schmucker and Bridget C. Pals, all from Northwestern.

26 August 2015,
 0

Chemistry report on atoms use this article :This article presents an activity that focuses on helping students investigate the formation of rocks, minerals, and […]


26 August 2015

Compare and contrast: An essay that expands upon and contextualizes the historical, political and cultural events, as well as the films and/or filmmakers, which have influenced and shaped cinemaCompare and contrast: An essay that expands upon and contextualizes the historical, political and cultural events, as well as the films and/or filmmakers, which have influenced and shaped cinema

26 August 2015,
 0

Compare and contrast: An essay that expands upon and contextualizes the historical, political and cultural events, as well as the films and/or filmmakers, which […]


26 August 2015

To encourage healthy eating, higher taxes should be imposed on soft drinks and junk food.

To encourage healthy eating, higher taxes should be imposed on soft drinks and junk food.


26 August 2015,
 0

To encourage healthy eating, higher taxes should be imposed on soft drinks and junk food. To encourage healthy eating, higher taxes should be imposed […]


26 August 2015

Parenting efforts have nothing to do with predation since genetic propensities of the child may interfere with or not respond to parenting efforts.
Reaction Paper
 Parenting efforts have nothing to do with predation since genetic propensities of the child may interfere with or not respond to parenting efforts.
The paper must be at least 250-300 words, excluding the title page and reference page, and must adhere to the APA sixth edition writing format. Please reference the APA example given in the Resources section. If your paper does not comply with this format you will lose points. Please see the grading rubric that follows the list of Controversial Statements. Please cite at least one reference from a website provided in the Webliography and one from your text book. Please make sure to submit your paper to Turnitin.com

26 August 2015,
 0

Parenting efforts have nothing to do with predation since genetic propensities of the child may interfere with or not respond to parenting efforts. Reaction […]


26 August 2015

What is your business justification for the big data project

Big Data
Many organizations today are experiencing challenges with making data-driven decisions when it comes to data management solutions such as Big Data. As the rapid growth of the current state and the future state of data evolves within an organization, it would be foolhardy to make a data-driven decision without attempting to gain insight on meaningful inferences from the data. Additionally, database silos, petabytes of unstructured data and a dearth of data scientists and data administers are the main obstacles to putting Big Data to work effectively in helping to make business decisions.
For your final project, describe the following using the readings and some of the concepts that have been covered in the previous weeks.
Please respond to the following questions in your final project report:
◦What is your business justification for the big data project?
◦How did you implement big data with (in-house personnel, or did you engage professional services partners)?
◦Did you implement big data as enhancement to existing data analytics platform, or through an entirely new infrastructure?
◦Did your personnel need to enhance their technical skillsets and certifications to get started with the implementation of big data?
◦How do you plan to evolve your big data investment?
◦What were some of the challenges you experienced in locating big data within the database silos?

Supplementary Resource: Article – http://tdwi.org/webcasts/2013/03/how-big-data-is-adding-to-data-management-challenges.aspx?tc=page0
Books – Loshin, D. (2003). Business intelligence: The savvy manager’s guide (1st ed.). Burlington, MA: Morgan Kaufmann

Williams S., & Williams, N. (2006). The profit impact of business intelligence (1st ed.). Burlington, MA: Morgan Kaufmann

Deliverables

Your final report should not be less than eight to ten pages in length. Be sure the report is in Arial 12-pt font, with double spacing and APA formatting.

26 August 2015,
 0

What is your business justification for the big data project Big DataMany organizations today are experiencing challenges with making data-driven decisions when it comes […]


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