Monthly Archives: August 2014

Jean-Pierre Sauvage’s Molecular Machines

  If you look about biological field, “molecular motors” or “machines” have a crucial roles. These systems are composed of multi components involving large amplitude for geometrical changes or locomotion of only one component of the system. These both attitudes are under the action of an external stimuli which can be a variation of pH, Redox process, etc.

Molecular Motors consist of several units:

  • One without any motion called the rotor
  • All the other parts move, called the stator

It’s like the fuel similar in biological systems to the ATP.

Linear motors and rotary motors have been both studied. Whereas linear motors are know for many years, rotary motors has required lot of works by Pr Jean-Pierre Sauvage and his lab team, where they have identified then investiged this kinds of motors.

One of the most popular and extraordinary rotatory motors is the ATPase: look at the picture over the text.

ATPase is the stator called c and γ and the rotor is made with six proteins αβ.

In order that, whereas the subunit of the rotor according to a pH gradient, there is production of ATP!

   On the schema, the biological rotary is called γ and c: the mobile portion. And the six proteins αβ which form the stator of the motor are motionless.

References: Pr JP Sauvage Works

Chemistry is all around us!

 Everything we hear, smell, taste, touch and see involves chemistry. Hearing, smelling, tasting, touching and seeing, involve several series of chemical reactions and interactions in our body. Consequently, know about chemistry is understand the world around us.

In other terms, chemistry is the study of the matter and the changes it can product.

Matter is anything which has a mass, and occupies a space, involving everything we can touch. There is a countless of matter all around us, this matter is composed of some hundreds of chemical elements. These elements are for instance, chlorine, silver or copper, etc. Nevertheless, the matter isn’t composed of chemical elements but composed of different combinaisons of these chemical elementsNuance-.

The prodigy of chemistry is when these basic particles are combined they make something new and unique.

If we take for example in the one hand, the sodium element “Na”: it’s an alkaline, soft and silver metal. When we put it in water, it reacts violently with the H2O molecules, giving hydrogen gas “H2”, and enough heat to make an explosion from the hydrogen gas producted

In an other hand, we take the example of chlorine element “Cl”: it’s an halogen, with a green color, a gas under the standard conditions ( 25°C or 298 K, 1 atom). It’s a very caustic and nasty gas using for these proprieties as a chemical warfare during World Wars.

Everybody know the formula of sodium chloride “NaCl”, so what could give as dangerous reaction the combinaison of these two elements ?! You could be surprised but just the common table salt “NaCl”…

Of course, everybody know that chemistry is not limited only to the mixture in the laboratories. It all around us and:

                                               The better we know chemistry, the better we know our world!

Rise to Henry Tate: A great British in the history of the National Gallery

In 1889, Henry Tate wrote to the National Gallery offering 65 paintings to the nation. However the man asked the Gallery that the works, all by British artists should be shown in their own room. They due to reject this offer because of a lack of place. But they were inspired to start planning a gallery dedicated to British art. 

An anonymous donor offered £80,000 towards the cost of an edifice such a museum, so they could approve the site, following they found the anonymous donor was Henry Tate!

Several sites were proposed with locations but it’s in 1852, they chose the derelict Millbank Prison, described By Charles Dickens in “David Copperfield”.

The National Gallery opened in 1897 with just ten rooms and 245 pictures and has adopted the nickname 35 years later of Tate. An architect unearthed and reinstalled dome of Smith’s original details as the balcony which is opens to visitors since 1920.

Unfortunately, on 7 January 1928, the Gallery lost 18 paintings but could save the most of the works. The Thames burst its banks and nine of the Tate’s basement galleries were submerged under eight feet of freezing water.

An other worse threat came in 1939 during Wold War II. Some of the paintings were moved but the museum itself was hit by a bomb. We can still look the blast damage on the wall.

However, the Tate reopened in 1946 after the end of the War and in 1960 a remodelling of the building was proposed. The museum was extended when its international collection moved to Tate Modern in 2000. 

Now, The National is a national treasure.

Thank Henry Tate!

The National Gallery: Analysis of the paintings

     The National Gallery is an Art Museum in Trafalgar Square in London founded in the 1842 years. All the painting’s collections are dating from the 13th to the 18th Century.

Some scientific researches about materials and technology of old paintings has been conduct at this National Gallery by scientists. Pigments, paints, varnishes and all the materials used for the conservation give very important informations on the chemical of the materials which were used in the works of these paintings. The researches use the analytical equipments as: IR microscopy, scanning electron microscopy, energy-dispertive X-Ray analysis, etc (1).

A video focused on microscopy to see the layers structure of painting (2) shows us, a man,, David Peggy investigates materials as varnishes, pain binder and pigment and a woman working also in the Gallery investigates about less structure paintings, identifies and analyzes the pigments. All these works allowed a good conservation of these paintings.

A picture is fascinating; The portrait of Alexander Mornauer. When the gallery bought it, the background of the picture was blue and through the time turns about a brownish color. So, the blue picture was examined by micro chemical test and chemists discovered this Prussian blue was a later addition.

During the examination of the picture, they shown different layers, this allows to have an uniform surface:

The panel painting construction is:

  1. Wood
  2. Ground/preparation layer
  3. Drawing layer
  4. Paint layer
  5. Varnish which protects the picture.

To understand why the background of the picture have changed, they have taken a paint sample and look it at the microscope, which effectively shown the blue paint wasn’t the initial color but it was a brown color.

What is the event which makes this modification of color? Perhaps a chemical reaction between the different pigments, we don’t really know.

But, this show us a very interesting way in chemistry, using scientific knowledges and analytical techniques, a chemist can go into the history of the painting and finds the best conditions of painting conservation.

References:

  1. 10 years ago: art analysis at the National Gallery, Chemistry World, 3 April 2014 (RSC)
  2. Video about analytical chemist at the National Gallery (RSC)

Removing odor from wastewater by means of bacteria

       The company EcoVerde, designed a new system of filtration, able to remove odor and polluants which are in the wastewater. This through a biological process: some bacteria deed on hydrogen sulfide.

This process greener environmentally speaking than the already known agents because it doesn’t use any chemical product. EcoVerde is a Company created in the USA by Uribe Lobo.

The principle is easy: Air is extracted from sewage or industrial wastewater then sent to a system whose name is Bioscrubber EG [1]. There is evaporation and an other way for directs contaminants, for instance: ammonia NH3, Mercaptan (sulfur derivatives), and hydrogen sulfide H2S. These contaminants are responsible of all the bad odors, and are directed to a filter were bacteria eliminate them.

“The Bioscrubber EG is based on a non-degradable filter where we place and adhere various types of bacteria which are selected depending on the applications and contaminants. The removal of polluants occurs through a natural processor oxidation. Odors are consumed by microorganisms, so that the more polluted the air, there will be more food for the bacteria without incurring any cost” [2].

But, it’s important to know, each bacteria used by EcoVerde remove specific pollutants:

  • Autotrophic bacteria remove hydrogen sulfide H2S and methane CH4
  • Heterotrophic bacteria remove volatile organic compounds 

EcoVerde ‘s matrix is in the USA but hope to expand this service to other countries [3].

References:

  1. Sciencedaily, August 24, 2014
  2. Uribe Lobo’s speech
  3. Materials, In vestigacion y Dessarollo.

               

Photosynthesis: Summarize and quiz !

 Summarize

   Organisms need energy to survive. Some of them can absorb energy from the sunlight and use it to produce sugar and other organic compounds. You certainly know this process under the name of “photosynthesis”, used by plants and some bacteria or blue-green algae. Carbon dioxide nCO2 and water nH20 under sunlight and in presence of chlorophyll product glucose (CHOH)n and oxygen nO2.

In the photosynthesis there are two reactions:

The first is the “light reactions”, energy of light is conserved as high energy involving ATP and NADPH. The proteins and pigments responsible for the photosynthetic light reaction are associated with thylakoid (grana) membranes.

The second is called Calvin cycle, and on the contrary of the first is the “dark reactions pathway”. Enzymes and intermediates of the cycle are located in the chloroplast stroma.

 Now make this little Quiz (A to J), to check your knowledges. After you’ll find the good answers at the end of the quiz.

A) Which of the following are capable of photosynthesis

  1. Plants, and animals
  2. plants, some bacteria, some protists, some algae
  3. Plants and some protists only

B) In plants, photosynthesis mainly occurs in the:

  1. Leaves
  2. Roots
  3. Flowers

C) Plants use carbon dioxide, water and sunlight to produce water, glucose and …..

  1. Oxygen
  2. Nitrogen
  3. Carbone dioxide

D) This green pigment captures the sun’s energy in photosynthesis

  1. Chlorophyll
  2. Thylakoid
  3. Stroma

E) Light reactions mostly occur in which part of the chloroplast?

  1. Stomata
  2. Stroma
  3. Grana

F) Dark reactions occur in which part of the chloroplast?

  1. Outer membrane
  2. Stroma
  3. Stromate

G) True or False, Dark reactions in most plants occur during the day:

  1. True
  2. False

H) In Calvin Cycle, Carbon dioxid is converted to:

  1. Protein
  2. Sugar
  3. Fat

I) Both, ATP and NADPH are pro ducted in the ……………………………. of photosynthesis

  1. Light reaction phases
  2. Dark reaction phases

J) Which is the chemical equation for photosynthesis in plants?

  1. C6H12O6 + 6O2 + ATP —> 6CO2 + 6H20
  2. 6CO2 + 12 H20 + light —> C6H12O6 + 6O2 + 6H20
  3. C6H12O6 + 6O2 —> 6CO2 + 6H20 + Energy

Correction: A2, B1, C1, D1, E3, F2, G1, H2, I1, J2.

 

    

 

 

A 3D molecules website with all about molecular’s properties

I advice you this really wonderful website, you can see all about the molecules of your choice:

  1. The 3D structure
  2. Molecular properties
  3. Lewis structure
  4. spin the molecule
  5. symetry group
  6. Molecular vibrations
  7. Molecular Orbitals
  8. angles and lenghts bonds

                                                     http://www.chemeddl.org/resources/models360/models.php

President Barack Obama goes green

    Barack Obama has shown last May, a scientific report about the effects due to the climatic change on the American territory. The housings and infrastructures are in a great danger also, ecosystem and economy are disrupted. 

    The President Barak Obama, capped about the focus on the climate change and has a push for make huger energy efficiency. This month, the administration issue new regulations to decrease carbon emissions from existing power plants. The White House released the Nation climate appraisal, which informed about the effects of climate change were immediate and about all the territory. Obama searched to highlight the focus in interviews with meteorologists, etc.

    The White House celebrated the completion of a symbolic accomplishment: the installation of solar panels on all the White House.

    President Obama announced a series of corporate pledges to increase renewable energy use and all to boost solar production. 

    He said according to MCT ” Together, the commitments we are announcing today prove that there are cost-effective ways to tackle climate change and create new jobs in the same way […] Inside of Washington, we have still got some climate deniers who shout loud, but they are wasting everybody’s time on a settle debate”

    However, only 29 percent of Americans believe that global warming should be a priority for the President. But a poll in March found that about 70 percent of Americans between 16 and 29 years old said be worried about climate change.