Excel

   Linear regression is an approach to modeling the relationship between a scalar variable y and one or more variables denoted X. In linear regression, models of the unknown parameters are estimated from the data using linear functions. Such models are called linear models. Most commonly, linear regression refers to a model in which the conditional mean of y given the value of X is an affine function of X. Less commonly, linear regression could refer to a model in which the median, or some other quantile of the conditional distribution of y given X is expressed as a linear function of X. Like all forms of regression analysis, linear regression focuses on the conditional probability distribution of y given X, rather than on the joint probability distribution of y and X, which is the domain of multivariate analysis.

   Quadratic regression models are often used in economics areas such as utility function , forecasting, cost-befit analysis, etc. This JavaScript provides parabola regression model. This site also presents useful information about the characteristics of the fitted quadratic function.

In order to solve problems involving quadratic regression, it is necessary to

• know how to enter data into your graphing calculator for completing modeling problems
• know how to solve quadratic equations
• know how to calculate a quadratic equation that best fits a set of given data
• write and solve an equation for the problem

 The examples are as follows :

         

 -Beer's Law Scatter Plot and Linear Regression-

 -Titration of 50 ml of 0.1 M HCl with 0.1 M Na0H-

 -Line Best Fit-

Quadratic Regression-

Smiles

  SMILES (Simplified Molecular Input Line Entry System) is a line notation (a typographical method using printable characters) for entering and representing molecules and reactions. 
  SMILES contains the same information as might be found in an extended connection table. The primary reason SMILES is more useful than a connection table is that it is a linguistic construct, rather than a computer data structure. SMILES is a true language, albeit with a simple vocabulary (atom and bond symbols) and only a few grammar rules. SMILES representations of structure can in turn be used as "words" in the vocabulary of other languages designed for storage of chemical information (information about chemicals) and chemical intelligence (information about chemistry).

Part of the power of SMILES is that unique SMILES exist. With standard SMILES, the name of a molecule is synonymous with its structure; with unique SMILES, the name is universal. Anyone in the world who uses unique SMILES to name a molecule will choose the exact same name.

One other important property of SMILES is that it is quite compact compared to most other methods of representing structure. A typical SMILES will take 50% to 70% less space than an equivalent connection table, even binary connection tables. For example, a database of 23,137 structures, with an average of 20 atoms per structure, uses only 1.6 bytes per atom when represented with SMILES. In addition, ordinary compression of SMILES is extremely effective. The same database cited above was reduced to 27% of its original size by Ziv-Lempel compression (i.e. 0.42 bytes per atom).

These properties open many doors to the chemical information programmer. Examples of uses for SMILES are:

• Keys for database access
• Mechanism for researchers to exchange chemical information
• Entry system for chemical data
• Part of languages for artificial intelligence or expert systems in chemistry

Structural images of SMILES

Structural image	SMILES notation
	C=CC\C=C\O
	CCN(CC)CC
	CC(C)C(=O)O
	CC(C)C(CCC)C(CCC)C=C
	C1CCCCC1
	CC1=CC(Br)CCC1
	C1CN(CCC1)C2CCCCO2
	c1ccco1
	Oc1ccncn1
	c1ccccn1
	ON1CCCCC1
	O[n+]1ccccc1
	Oc1ccccc1
	Cn1cccc1
	C[C@H]=C\C=C\F
	c1cccn1
	Oc1ccccn1
	C\C=C\C=C\F

Protein Data Bank

  The Protein Data Bank (PDB) is a repository for the 3-D structural data of large biological molecules, such as proteins and nucleic acids. The data, typically obtained by X-ray crystallography or NMR spectroscopy and submitted by biologists and biochemists from around the world, are freely accessible on the Internet via the websites of its member organisations (PDBe, PDBj, and RCSB). The PDB is overseen by an organization called the Worldwide Protein Data Bank, wwPDB.

  The PDB is a key resource in areas of structural biology, such as structural genomics. Most major scientific journals, and some funding agencies, such as the NIH in the USA, now require scientists to submit their structure data to the PDB. If the contents of the PDB are thought of as primary data, then there are hundreds of derived (i.e., secondary) databases that categorize the data differently. For example, both SCOP and CATH categorize structures according to type of structure and assumed evolutionary relations; GO categorize structures based on genes.<sup>[1]

Pictures shown below are the examples of protein structure.</sup>

                                         Subtilisin

  Subtilisin (serine endopeptidase) is a non-specific protease (a protein-digesting enzyme) initially obtained from Bacillus subtilis.

Subtilisins belong to subtilases, a group of serine proteases that initiate the nucleophilic attack on the peptide (amide) bond through a serine residue at the active site. They are physically and chemically well-characterized enzymes. Subtilisins typically have molecular weights of about 20,000 to 45,000 dalton. They can be obtained from soil bacteria, for example, Bacillus amyloliquefaciens. Subtilisins are secreted in large amounts from many Bacillus species.

                                         Prolyl Aminopeptidase

  Xaa-Pro aminopeptidase 1 is an enzyme that in humans is encoded by the XPNPEP1 gene.^[1]
X-prolyl aminopeptidase (EC 3.4.11.9) is a proline-specific metalloaminopeptidase that specifically catalyzes the removal of any unsubstituted N-terminal amino acid that is adjacent to a penultimate proline residue. Because of its specificity toward proline, it has been suggested that X-prolyl aminopeptidase is important in the maturation and degradation of peptide hormones, neuropeptides, and tachykinins, as well as in the digestion of otherwise resistant dietary protein fragments, thereby complementing the pancreatic peptidases. Deficiency of X-prolyl aminopeptidase results in excretion of large amounts of imino-oligopeptides in urine (Blau et al., 1988).[supplied by OMIM]^[1]

                                         Lex A Repressor

  Repressor LexA or LexA is a repressor enzyme (EC 3.4.21.88) that represses SOS response genes coding for DNA polymerases required for repairing DNA damage. LexA is intimately linked to RecA in the biochemical cycle of DNA damage and repair. RecA binds to DNA-bound LexA causing LexA to cleave itself in a process called autoproteolysis.
DNA damage can be inflicted by the action of antibiotics. Bacteria require topoisomerases such as DNA gyrase or topoisomerase IV for DNA replication. Antibiotics such as ciprofloxacin are able to prevent the action of these molecules by attaching themselves to the gyrase - DNA complex. This is counteracted by the polymerase repair molecules from the SOS response. Unfortunately the action is partly counterproductive because ciprofloxacin is also involved in the synthetic pathway to RecA type molecules which means that the bacteria responds to an antibiotic by starting to produce more repair proteins. These repair proteins can lead to eventual benevolent mutations which can render the bacteria resistant to ciprofloxacin.

Chemsketch

Type	Graphical Object
Energy Diagram
Orbitals
Distillation
DNA Strand
Lipids

   ACD/ChemSketch Freeware is a popular and comprehensive chemical drawing package, intended for home and educational use only. Since 1998, ACD/Labs has provided ChemSketch freeware to >330 academic institutions worldwide. Every day another 500 downloads from the ACD/Labs Web site further distributes the power of this chemical structure drawing package to desktops around the world. Among many other features, this product offers IUPAC chemical naming (up to 50 functional atoms); prediction of logP; comprehensive report creation; tautomer recognition; 2D structure cleaning; 3D optimization and viewing; drawing of polymers, organometallics, and Markush structures; and as well as access to the chemistry Web search engines PubChem, eMolecules, and ChemSpider.
Version 11.01 build 22419 includes several changes such as interface changes, improvements in structure representation, augmented handling of images and files, and other improvements.

The Amazing HTML

What Is HTML?
Ah, the eternal question... Well, actually, no. But still, it obviously puzzles enough people.

Okay, here goes some infos about HTML.

HTML, which stands for HyperText Markup Language, is the predominant markup language for web pages. A markup language is a set of markup tags, and HTML uses markup tags to describe web pages.
HTML is written in the form of HTML elements consisting of "tags" surrounded by angle brackets (like <html>) within the web page content. HTML tags normally come in pairs like <b> and </b>. The first tag in a pair is the start tag, the second tag is the end tag (they are also called opening tags and closing tags).
The purpose of a web browser is to read HTML documents and display them as web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page.
HTML elements form the building blocks of all websites. HTML allows images and objects to be embedded and can be used to create interactive forms. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It can embed scripts in languages such as JavaScript which affect the behavior of HTML webpages.
HTML can also be used to include Cascading Style Sheets (CSS) to define the appearance and layout of text and other material. The W3C, maintainer of both HTML and CSS standards, encourages the use of CSS over explicit presentational markup.

Besides that,

HTML is a computer language devised to allow website creation. These websites can then be viewed by anyone else connected to the Internet. It is relatively easy to learn, with the basics being accessible to most people in one sitting; and quite powerful in what it allows you to create. It is constantly undergoing revision and evolution to meet the demands and requirements of the growing Internet audience under the direction of the » W3C, the organisation charged with designing and maintaining the language.
The definition of HTML is HyperText Markup Language.

• HyperText is the method by which you move around on the web — by clicking on special text called hyperlinks which bring you to the next page. The fact that it is hyper just means it is not linear — i.e. you can go to any place on the Internet whenever you want by clicking on links — there is no set order to do things in.
• Markup is what HTML tags do to the text inside them. They mark it as a certain type of text (italicised text, for example).
• HTML is a Language, as it has code-words and syntax like any other language.

How does it work?

HTML consists of a series of short codes typed into a text-file by the site author — these are the tags. The text is then saved as a html file, and viewed through a browser, like Internet Explorer or Netscape Navigator. This browser reads the file and translates the text into a visible form, hopefully rendering the page as the author had intended. Writing your own HTML entails using tags correctly to create your vision. You can use anything from a rudimentary text-editor to a powerful graphical editor to create HTML pages.

What are the tags up to?

The tags are what separate normal text from HTML code. You might know them as the words between the <angle-brackets>. They allow all the cool stuff like images and tables and stuff, just by telling your browser what to render on the page. Different tags will perform different functions. The tags themselves don’t appear when you view your page through a browser, but their effects do. The simplest tags do nothing more than apply formatting to some text, like this:

<b>These words will be bold</b>, and these will not.

In the example above, the <b> tags were wrapped around some text, and their effect will be that the contained text will be bolded when viewed through an ordinary web browser.
If you want to see a list of a load of tags to see what’s ahead of you, look at this tag reference. Learning the tags themselves is dealt with in the next section of this website, My First Site.

Is this going to take long?

Well, it depends on what you want from it. Knowing HTML will take only a few days of reading and learning the codes for what you want. You can have the basics down in an hour. Once you know the tags you can create HTML pages.
However, using HTML and designing good websites is a different story, which is why I try to do more than just teach you code here at HTML Source — I like to add in as much advice as possible too. Good website design is half skill and half talent, I reckon. Learning techniques and correct use of your tag knowledge will improve your work immensely, and a good understanding of general design and the audience you’re trying to reach will improve your website’s chances of success. Luckily, these things can be researched and understood, as long as you’re willing to work at it so you can output better websites.
The range of skills you will learn as a result of running your own website is impressive. You’ll learn about aspects of graphic design, typography and computer programming. Your efficiency with computers in general increases.You’ll also learn about promotion and your writing will probably improve too, as you adapt to write for certain audiences.

Do I have to be online all the time?

Not at all. You can code your entire website offline, storing it all on your own computer, and then just transfer all the files onto the web. Then whenever you have new content, you just add that to the existing online version of your site. It’s really quite simple.

Is there anything HTML can’t do?

Of course, but since making websites became more popular and needs increased many other supporting languages have been created to allow new stuff to happen, plus HTML is modified every few years to make way for improvements.
Cascading Stylesheets are used to control how your pages are presented, and make pages more accessible. Basic special effects and interaction is provided by JavaScript, which adds a lot of power to basic HTML. Most of this advanced stuff is for later down the road, but when using all of these technologies together, you have a lot of power at your disposal.

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Topic	Example
HTML Colour Table
HTML Fonts