I hear I forget

I see I remember

I do I understand

 Migaa

Hercules new words

Hercules Cartoon
New Words
Please write down the new words!
 
•Scene1 -      part1
•Finds out-   know
• Mortal-      in danger
•Prove-         show
•Hero- famous good man

•Earth-        world
•Godhood-  god life
•Restore-     restart
•Convince-  ask
•Mixed up-  do

•Stuff - thing
•Never be able - can’t
•Rejoin - go back to
•Hold it - wait
Hercules
1.Hades is going to kill us when he finds out what happened.
2.If you can prove yourself a true hero on earth, your godhood will be restored.
1.If I don’t become a true hero, I’ll never be able to rejoin my father, Zeus.
2.If you don’t help him now Phil, he’ll die.
 
 
 

Grammar lecture word order

Unit 1: Understanding English Sentence Structure
To master correct sentence structure, you need to understand how sentences are organized grammatically. This unit explains the basis of English sentence structure—subjects and verbs. Most sentences in English follow the pattern below.
Subject + verb + words that complete the thought of the sentence
S V Direct Object S V Subject Complement Yvette won the race. The cake looks delicious.
The core of the sentence is the connection between the subject and verb, which gives the sentence its essential meaning. If you can recognize subjects and verbs, you are on your way to creating sentences that express your ideas clearly and correctly.
Recognizing Verbs
1. One way to recognize verbs is to know what they do. A verb can express
• a physical or mental action: run, write, take, give, think, calculate, hope
• a state of being: be (e.g., am, is, are, will be), seem, look
• a state of owning: have, possess, own
• a sensation (feel, smell, taste)
NOTE: Some verbs can express more than one thing, depending on how they are used. Look at the differences in the meaning of look and taste in the following sentences.
I looked at him in total surprise. (Looked expresses an action.)
You look tired today. (Look expresses a state of being.)
Jerome tasted the soup. (Tasted expresses an action.)
The soup tastes salty. (Tastes expresses a state of being.)
2. Another way to recognize a verb is to look for the word(s) in the sentence whose form will change if you change the time of the sentence, e.g., from present to past or future.
Fred eats lunch at noon.
To find the verb, change the time of the sentence.
Yesterday, Fred ate lunch at noon. OR
Tomorrow, Fred will eat lunch at noon.
The word in the first sentence that changes form is eats. Therefore eats is the verb.
Exercise
Directions: Underline the verb in each of the following sentences. NOTE: If you see to in front of a verb, e.g., to include, that word does not function as a verb in the sentence.
1. At the beginning of a university term, students are generally happy about taking new courses and making a new beginning.
2. Unfortunately, over the term, natural motivation fades.
3. Around midterm, students start to have doubts.
4. They feel unsure about being able to learn enough material in the course to pass.
5. However, by setting realistic goals and working hard to achieve them, students will succeed in their studies.
Recognizing Subjects
The easiest way to recognize the subject in a sentence is first to find the verb. Then look for the word(s) in front of the verb that answers the question “Who or what?”
Marian wants a new CD player for Christmas.
(a) Find the verb by changing the time of the sentence: Marian will want a new CD player for Christmas. [The change is in “will want.”]
(b) The verb in the original sentence is wants.
(c) Ask, “Who wants a new CD player for Christmas?”
(d) The answer to the question is Marian. Therefore Marian is the subject.
Skiing in the mountains is dangerous in the spring.
(a) Change the time: Skiing in the mountains was dangerous in the spring.
(b) The verb in the original sentence is is.
(c) Ask, “What is dangerous in the spring?”
(d) The subject is skiing.
Exercise
Directions: Underline the subject in each of the following sentences.
1. Jake does not have the right attitude to succeed at university.
2. Unfortunately, he expects the professors to hand out knowledge to him.
3. However, the professors want students to take responsibility for their own learning.
4. Successful students regard assignments and tests as opportunities to learn.
5. They want to accept the challenges set by their professors.
Recognizing Subjects and Verbs in Special Cases
Below are examples of sentences that do not follow the standard pattern.
1. Sentences that express a request or command. In these sentences, the subject is not stated but is understood to be “you.” The sentence is asking the reader or listener (the “you”) to do something. It is possible in this case to have a one-word sentence, as in the following examples:
Stop. Help! Run! [Each of these words is a verb, and the subject of each is “you understood.” Each of these constructions is therefore a complete sentence.]
Here are other examples of command/request sentences in which “you” is understood to be the subject:
V Turn to page 23 in your textbook.
V Wait for me at the entrance to the cafeteria.
V Go to the store for some milk.
2. sentences that begin with here or there. In these sentences, here and there are not subjects. In fact, in such sentences the subject comes after the verb.
V S
Here are the new office supplies.
V S
There is Trevor at the front door.
3. Questions. In most questions, the subject comes either after the verb (if the verb is one word) or between parts of the verb (if the verb consists of more than one word).
V S
What is your name?
V S V
Where do you live?
V S V Would you like some tea?

Chemistry lecture 36

NATURAL PRODUCT

A natural product is a chemical compound or substance produced by a living organism - found in nature that usually has a pharmacological or biological activity for use in pharmaceutical drug discovery and drug design. A natural product can be considered as such even if it can be prepared by total synthesis.

These small molecules provide the source or inspiration for the majority of FDA-approved agents and continue to be one of the major sources of inspiration for drug discovery. In particular, these compounds are important in the treatment of life-threatening conditions.

NATURAL SOURCES

Natural products may be extracted from tissues of terrestrial plants, marine organisms or microorganism fermentation broths. A crude (untreated) extract from any one of these sources typically contains novel, structurally diverse chemical compounds, which the natural environment is a rich source of.

Chemical diversity in nature is based on biological and geographical diversity, so researchers travel around the world obtaining samples to analyze and evaluate in drug discovery screens or bioassays. This effort to search for natural products is known as bioprospecting.

 

SCREENING OF NATURAL PRODUCTS

Pharmacognosy provides the tools to identify, select and process natural products destined for medicinal use. Usually, the natural product compound has some form of biological activity and that compound is known as the active principle - such a structure can act as a lead compound (not to be confused with compounds containing the element lead). Many of today's medicines are obtained directly from a natural source.

On the other hand, some medicines are developed from a lead compound originally obtained from a natural source. This means the lead compound:

• can be produced by total synthesis, or
• can be a starting point (precursor) for a semisynthetic compound, or
• can act as a template for a structurally different total synthetic compound.

This is because most biologically active natural product compounds are secondary metabolites with very complex structures. This has an advantage in that they are extremely novel compounds but this complexity also makes many lead compounds' synthesis difficult and the compound usually has to be extracted from its natural source - a slow, expensive and inefficient process. As a result, there is usually an advantage in designing simpler analogues.

TRADITIONAL MEDICINE

In the past, traditional peoples or ancient civilizations depended greatly on local flora and fauna for their survival. They would experiment with various berries, leaves, roots, animal parts or minerals to find out what effects they had. As a result, many crude drugs were observed by the local healer or shaman to have some medical use. Although some preparations may have been dangerous, or worked by a ceremonial or placebo effect, traditional healing systems usually had a substantial active pharmacopoeia, and in fact most western medicines up until the 1920s were developed this way. Some systems, like traditional Chinese medicine or Ayurveda were fully as sophisticated and as documented systems as western medicine, although they might use different paradigms. Many of these aqueous, ethanolic, distilled, condensed or dried extracts do indeed have a real and beneficial effect, and a study of ethnobotany can give clues as to which plants might be worth studying in more detail. Rhubarb root has been used as a purgative for many centuries. In China, it was called "The General" because of its "galloping charge" and was only used for one or two doses unless processed to reduce its purgative qualities. (Bulk laxatives would follow or be used on weaker patients according to the complex laxative protocols of the medical system.^[3]) The most significant chemicals in rhubarb root are anthraquinones, which were used as the lead compounds in the design of the laxative dantron.

The extensive records of Chinese medicine about response to Artemisia preparations for malaria also provided the clue to the novel antimalarial drug artemisinin. The therapeutic properties of the opium poppy (active principle morphine) were known in Ancient Egypt, were those of the Solanaceae plants in ancient Greece (active principles atropine and hyoscine). The snakeroot plant was well regarded in India (active principle reserpine), and herbalists in medieval England used extracts from the willow tree(salicin) and foxglove (active principle digitalis - a mixture of compounds such as digitoxin, digitonin, digitalin). It can be challenging to obtain information from practitioners of traditional medicine unless a genuine long term relationship is made. Ethnobotanist Richard Schultes approached the Amazonian shamans with respect, dealing with them on their terms. He became a "depswa" - medicine man - sharing their rituals while gaining knowledge. They responded to his inquiries in kind, leading to new medicines.^[4] On the other hand Cherokee herbalist David Winston recounts how his uncle, a medicine priest, would habitually give misinformation to the visiting ethnobotanists. The acupuncturists who investigated Mayan medicine recounted in Wind in the Blood had something to share with the native healers and thus were able to find information not available to anthropologists.^[5] The issue of rights to medicine derived from native plants used and frequently cultivated by native healers complicates this issue.

 

ISOLATION AND PURIFICATION

If the lead compound (or active principle) is present in a mixture of other compounds from a natural source, it has to be isolated and purified. The ease with which the active principle can be isolated and purified depends much on the structure, stability, and quantity of the compound. For example, Alexander Fleming recognized the antibiotic qualities of penicillin and its remarkable non-toxic nature to humans, but he disregarded it as a clinically useful drug because he was unable to purify it. He could isolate it in aqueous solution, but whenever he tried to remove the water, the drug was destroyed. It was not until the development of new experimental procedures such as freeze drying and chromatography that the successful isolation and purification of penicillin and other natural products became feasible.

 

SYNTHESIS

Not all natural products can be fully synthesized and many natural products have very complex structures that are too difficult and expensive to synthesize on an industrial scale. These include drugs such as penicillin, morphine, and paclitaxel (Taxol). Such compounds can only be harvested from their natural source - a process which can be tedious, time consuming, and expensive, as well as being wasteful on the natural resource. For example, one yew tree would have to be cut down to extract enough paclitaxel from its bark for a single dose.^[6] Furthermore, the number of structural analogues that can be obtained from harvesting is severely limited.

A further problem is that isolates often work differently than the original natural products which have synergies and may combine, say, antimicrobial compounds with compounds that stimulate various pathways of the immune system:

Many higher plants contain novel metabolites with antimicrobial and antiviral properties. However, in the developed world almost all clinically used chemotherapeutics have been produced by in vitro chemical synthesis. Exceptions, like taxol and vincristine, were structurally complex metabolites that were difficult to synthesize in vitro. Many non-natural, synthetic drugs cause severe side effects that were not acceptable except as treatments of last resort for terminal diseases such as cancer. The metabolites discovered in medicinal plants may avoid the side effect of synthetic drugs, because they must accumulate within living cells.^[7]

Semisynthetic procedures can sometimes get around these problems. This often involves harvesting a biosynthetic intermediate from the natural source, rather than the final (lead) compound itself. The intermediate could then be converted to the final product by conventional synthesis. This approach can have two advantages. First, the intermediate may be more easily extracted in higher yield than the final product itself. Second, it may allow the possibility of synthesizing analogues of the final product. The semisynthetic penicillins are an illustration of this approach. Another recent example is that of paclitaxel. It is manufactured by extracting 10-deacetylbaccatin III from the needles of the yew tree, then carrying out a four-stage synthesis.

Chemistry lecture 35

INSTRUMENTAL CHEMICAL ANALYSIS

1. INTRODUCTION: BASIC PRINCIPLES AND TECHNIQUES

The need of the sophisticated analytical instruments and determinations using them is almost a routine process for the modern chemical laboratories. It has been a vast expanding area of knowledge as the instrument and computer manufacturers are producing analytical machines, which are in ever-increase of power and scope.

Basically, chemical analysis can be divided into three broad categories as given below, which are  almost  invariably  applied  to  major  areas  such  as  Fundamental  Research,  Product Development, Product Quality Control, Monitoring & Control of Pollutants, Medical & Clinical Studies, etc:

QUALITATIVE ANALYSIS:

Chemical analysis which just identifies one or more species present in a sample

QUANTITATIVE ANALYSIS:

Chemical analysis which finds out the total amount of the particular species present in a sample

STRUCTURAL ANALYSIS:

Chemical analysis which helps in finding the spatial arrangement of atoms in a molecule and the presence or position of certain organic functional groups in a given compound

Chemical analysis has some basic steps like, choice of method, sampling, preliminary sample treatment, separations, final measurement and assessment of results. It is with the first step viz. choice of method, care should be exercised to select the proper instrument to carry out fruitful analysis. A wrong selection at this point will lead to a meaningless analysis. Selection of the instrument is such important criteria!

2.  CLASSIFICATION OF THE ANALYTICAL TECHNIQUES

In a broad sense the techniques for the chemical analysis can be classified as follows:

Analysis through spectroscopy

Analysis through chromatography

Analysis through thermal energy

Analysis through x-ray techniques

Analysis through microscopy

Analysis through electrochemical techniques

Analysis through miscellaneous techniques

This classification is based on the interactions of molecules with various forms of energy like
electro-magnetic radiation, heat (thermal energy) and with matters like electrons. Each technique has specific principle, mode of operation, advantages and disadvantages.

3. Nuclear Magnetic Resonance Spectroscopy (NMR):

Principle: In NMR substances absorb energy in the radio frequency region of the electromagnetic spectrum under influence of a strong magnetic field.

Applications: The application lies mostly in the identification and structural analysis of organic compounds and thus, it is mostly a tool for qualitative analysis. It gives valuable information regarding the position of the functional groups in a molecule and provides distinguished spectra for the isomer. Much precise information on the structure of the compounds can be obtained using the same technique with other magnetic nuclei like C¹³, O¹⁷, the instrumentation being the same except that the sweep of the magnetic field is varied.

Disadvantages: Very expensive and the instrumentation is complex and needs exceptional skills to operate.  Its  sensitivity  ranges  from  moderate  to  poor,  however,  can  get  clear information using C¹³ or O¹⁷ NMR. The usage of the solvents is limited and in most of the situations deuterated solvents are required.

4. ANALYSIS THROUGH CHROMATOGRAPHY

The technique through which the chemical components present in complex mixtures are separated, identified and determined is termed as chromatography. This technique is widely used like spectroscopy and is a very powerful tool not only for analytical methods but also for preparative methods. Compounds of high grade purity can be obtained by this method. Chromatography can be simply defined as follows:

Based on the mobile phase this technique can be simply classified into two categories as:
Liquid Chromatography and Gas Chromatography. The column which holds the stationary phase (which in the form of small particles of the diameter of the order in microns), plays unique role in these processes. Usually silica is the base material for producing this phase.

4.1 LIQUID CHROMATOGRAPHY (LC/HPLC)

Principle: Early liquid chromatography was carried out in long glass columns with wide diameter. The diameters of the stacked particles inside the column were of the order of 150-200 microns range. Even then, the flow rates (eluent time) of the mobile phase with the analyte were very slow and separation times were long - often several hours!

The HPLC technique can be divided into four main categories depending on the nature of the processes that occur at the columns as follow:

4.1.1 High-Performance Adsorption Chromatography: Here the analyte species (components to be analysed) are adsorbed onto the surface of a polar packing. The stationary phase consists of finely divided solid particles packed inside a steel tube. If the component mixture is eluted through this tube with the mobile phase, different components present in the mixture adsorb to different degrees of strength and they become separated as the mobile phase moves steadily through the column.

4.1.2  High-Performance  Partition  Chromatography: It is the most  widely  used  liquid chromatographic  procedures  to  separate  most  kinds  of  organic  molecules. Here the components present in the analyte mixture distribute (or partition) themselves between the mobile phase and stationary phase as the mobile phase moves through the column. The stationary phase actually consists of a thin liquid film either adsorbed or chemically bonded to the surface of finely divided solid particles.

It finds wide applications in various fields, viz., pharmaceuticals, bio-chemicals, food products, industrial chemicals, pollutants, forensic chemistry, clinical medicine, etc.

GAS CHROMATOGRAPHY (GC)

Principle: Here an inert carrier gas (Helium or Nitrogen) acts as the mobile phase. This will carry the components of analyte mixture and elutes through the column. The column usually contains an immobilized stationary phase. The technique can be categorised depending on the type of stationary phase as follow:

Gas Solid Chromatography (GSC) - here the stationary phase is a solid which has a large surface area at which adsorption of components of the analyte takes place. The separation is possible based on the differences in the adsorption power and diffusion of gaseous analyte molecules. The application of this method is limited and is mostly used in the separation of the low-molecular-weight gaseous species like carbon monoxide, oxygen, nitrogen and lower hydrocarbons.

Gas Liquid Chromatography (GLC) - this is the most important and widely used method for separating and determining the chemical components of volatile organic mixtures. Here the stationary phase is a liquid that is immobilized on the surface of a solid support by adsorption or by chemical bonding. The separation of the mixture into individual components is by distribution ratio (partition) of these anayte components between the gaseous phase and the immobilized liquid phase. Because of its wide applications most of the GCs are configured for the GLC technique.