No Sweet Sense for Sweet Cats

We all like to eat sweet desserts; ice cream, candies, cakes, they're all part of our lives. The sweet taste is an ubiquitous element in all kinds of diets. And we, humans, are not the only lovers of sweet. Species from the Canidae family like the dog and its relatives also have an avidity for sweet foods, sweet being the indicator for carbohydrate rich edible things. Also, members of the Equidae (the horse and the donkey), Suidae (the pig), Ursidae (the brown bear - Ursus Arctos) amd other omnivourous species have the same tendency towards sugar.

However, not all animals are capable to sense sweet. Somehow, in the evolution process, a specific family of animals have lost this ability. It's the Felidae family. Little is known about the so called "big cats", such as the lion, the tiger or the panter. What is certain, is that the common cat (Felis Catus) is unable to detect the taste of even the most flavoured of sweets. It has been discovered that a deletion of an exon (coding part of the DNA) in the TAS1r2 gene is responsible for the loss of sweet taste in cats.

The deletion is marked in red. The numbers between brackets represent the exact number of nucleotides in each exon (the picture is adapted by me from the figure 2 of this article which I used as main reference).

Evolutionists say that natural selection didn't allow this taste to exist in cats because there was no need of it. The members of Felidae family are entirely carnivorous. The sweet taste allows omnivorous creatures to tell the difference between rich and poor carbohydrate food. But, because of the fact that meat of any kind is highly rich in these nutrients, there is no need for such a sense in cats. As a result, a mutation took place in this gene, taking out the unnecessary code, at a certain moment in the past.

Our cat on the fridge :-)

However, this certain moment is compuslorily subsequent to the swarving of cats from dogs, by reason of dogs manifesting a strong likelyhood for sweet. Personally, I think that humans may also have enhanced the dogs sweet sense as a result of the domestication process (so that the dogs have become almost omnivorous), but meanwhile, I'm sure that the contribution brought by humans in the development of canine taste senses is irelevantly small to be taken in consideration.

I would have also wanted to talk about a fellow gene of TAS1r2, the TAS2R38 gene (responsible for the ability or disability to taste PTC - a horrendously bitter chemical substance), but considering the length of the post, I'll do it with an other occasion (until then I would recommend you this wonderful book I'm reading: "When a Gene Makes You Smell Like a Fish"). See ya!

What Element Would You Like for Birthday?

Today is quite of a special day, my blog turns one :D For making this day like so, I made an appraisement on 50 people, regarding the topic "What element would you like for your birthday>".

Besides naming an element I expected also a reason for choosing a certain element. Almost a third of the participants answered Oxygen, because it is crucial for life developement on Earth. On the second position was Hydrogen due to the fact that in combination with the element mentioned earlier forms water. With only four votes, Carbon is on the third position, as consequence for its ability to form an infinite number of organic compounds.

People also had spontaneous reactions some of which were very funny. As an example, one russian guy said Chromium because it is used for plating guns (a pretty weird answer). Others said that gold or silver would be the perfect options just because they are shiny. Last but not least, a woman let me know that she desires an element that she could put in her husbands food so that he would stop cheating her in love :)).

Personally, I would choose Manganese, as it has different colours from one state of oxidation to an other (Mn⁷⁺ is purple,2Mn⁶⁺ is green, Mn⁵⁺ is cold blue and Mn²⁺ is crimson red).

I hope you like today's post. See you next time!

Olynth Nasal Spray

I have recently caught a cold. In the first days, apart from the sore throat sensation, my nose was totally congested, so I had to use a nasal spray. My option was Olynth. From curiosity at first, I read the list of components of this medicine. Then I thought I could find the way each and every of them acts to produce the general decongestioning effect of the spray and the way they are synthesized.

The composition of Olynth was: xylomethazoline chlorohydrate (the active substance), sorbitol (actually 1,2,3,4,5,6-hexanhexol), monosodium phosphate, benzalkonium chloride and disodium edetate.

The roles were the following:

• Xylometazoline can stimulate adrenaline receptors. As a response, the organism will consider the stimulus to be actually adrenaline and capillary vessels of blood will constrict (vasoconstriction is one of adrenaline symptoms), not allowing blood to irrigate the area. The capillary vessels near the mucus secretion glands will not be activated, so the process of mucus secretion will stop. As a remark, due to the adrenaline mimetism capabilities, xylometazoline is not recommended for persons with heart diseases.
• Sorbitol and the phosphate have the ability of retaining water (phosphate is a hidrate)
• Benzalkonium chloride acts as an antiseptic. The disodium edetate is a preservative, useful for enhancing the action of benzalkonium chloride.

Synthesis

Xylometazoline has a pretty easy way of synthesizing, albeit it is not visible from the beginning if we are to propose a possible method for doing this. So, after trying to find by ourselves the synthesis, Otilia, Silvian and I, finally bumped into the method sketched in this book: Strategies for Organic Drug Synthesis and Design.
The benzalkonium chloride is produced by reacting N,N-dimethylbenzylamine hidrochloride with a haloalcane. The reaction occurs as following:
The next reaction, although not very difficult to understand, it intrigued me because NAD⁺ and NADH, present here in the synthesis of sorbitol, have too a major role in the glycolisis process. NAD⁺ is a substance made of ADP and a ribose (pentose).
For the symplification of the synthesis of sorbitol, I'll show only the part of the molecule implied in the reaction. As it can be seen, when NAD⁺ reacts with D-fructose, NADH and sorbitol are produced.
I'll end this post by showing the structure of disodium edetate and monosodium phosphate.

Disodium edetate Monosodium phosphate So next time you'll use Olynth, you will definitely know how it actually works and how it's made. See you next time!

My Summer Holiday - Bicaz Trip

On the 26^th of July, me and my family started our family trip. We stayed at a floating hotel on the Bicaz Lake. The accommodation was pretty nice, and we had a great view of the lake from that point.

In the first three or four days we stayed at the hotel on the roof, getting a nice brown tan and also reading on chaise longues. Actually from this point of view, these eight days at Bicaz were really fulfilling: I have read Six Easy Pieces (R. Feynman), The Blind Watchmaker and A River Out Of Eden: A Darwinian View of Life, two books about evolution and natural selection from a very interesting perspective by the same author, Richard Dawkins.

In the fourth day, we went in a small trip around Bicaz Gorges and the Red Lake. When entering the Bicaz Canyon, the road becomes suddenly very tight. Rocky, vertical walls rise from both sides of the road and the Bicaz brook is on the right. It is extraordinary too see what such a small creek could have dug in millions and millions of years.

The Red Lake, a natural dam river, shaped in the form of an L, attracts many tourists, including us. A footpath surrounding the area is a great place to spend one or two hours walking. What is unique about this lake, is that pine stumps rise from the shallow water. Also, protected plants can be seen here on the edge of the track. For instance an endemic species of flowers, found only in Romania, Dianthus Callizonus, can be easily spotted here:

Dianthus Callizonus - endemic species of plants The Red Lake

As the fifth day came, we put on our sports shoes and reached the summit of Ceahlau mountain (Toaca Peak, 1907 m above sea level). It was a one hour hike from the base to a chalet at 1220 m high where we stayed and watched the scenic views and then went on climbing for another 2 hours and a half. Mainly, the track had a very steep angle but there were also plain bits of the footpath.

Me and my mom not being aware of the dozen kilometers path we were desiring to follow 'till the end of the day :D

We walked along the route for about an hour and a half until we found some benches to sit on. The place had a very spooky name "At the graves", but anyway we stopped to take a little rest.

Nothing to say, just watch

After another half an hour of hiking we stopped again (lazy us) at a place called "Cusma Dorobantului" (the soldier and his weapon), name inspired by the following piece of rock cutting through the sky.

Me on a pile of rocks

When seeing that the track leads us to a pasture, we were kind of relieved because we realized that this was the end, the so much desired peak. Although a splendid view was opening in front of our eyes, we made an idea of how much we still had to hike.

See that rocky peak? There we had to go

And as usually, when we finally were on the peak, the camera's battery died :)) . So sorry folks, but no images from the Toaca Peak today.

I leave the best subject for the next post: A Bulgarian All-Inclusive Experience.

NOTE: This post belongs to the series of posts "My Summer Holiday". The other post in this series is My Summer Holiday - The Olympiad.

Organic Chemistry Calculator

It's been a while since I last used a free online tool for chemistry, that combines different aspects of organic chemistry, such as: structure, stoichiometry and general reaction mechanisms. But yesterday evening, while searching on the internet, I found a seemingly useful, free, online tool that definitely caught my eye straightway.

It was a quite complex software produced by professor Andreas Herrmann's team in the Polymer Chemistry and Bioengineering department at Groningen University. The software allows you to draw the structures of different compounds and put them in printable version, to calculate the ammounts of substance needed in different organic reaction processes containing up to six reactions. So, I consider it to be pretty useful. Its link is the following: http://chemist.hosting.paran.com/orgchem/

To test the efficiency of this software, let's try to synthesize an organic compound, for instance urea (the first organic compound to be ever synthesized), from inorganic compounds. Firstly, fill in the name of the reaction in the title section, in this case Wöhler Synthesis. In the structure drawing section, let's draw the structural formula of urea.

Click on the double bond tool and then click in the middle of the drawing field.

Select the Oxygen tool and click in one of the double bond's ends.

Now select the simple bond tool and double click on the other end of the double bond. By doing this, two simple bonds will appear connected to the double bond.

Select Nitrogen tool and click on each of the simple bonds' free end. Now, urea should look like this:

Now look at the proper calculator. You know that AgNCO + NH₄Cl → (NH₂)₂CO + AgCl is the reaction implied. In the starting formula cell, introduce the formula of AgNCO and in the product formula cell write the formula of urea ((NH2)2CO). By pressing the ">" sign near these two cells the molar masses will be automatically generated. As a starting amount of AGNCO let's take 100 grams, for example. After doing this, press again the ">" in the current cell. The number of moles will be generated this time. Because the equation is balanced with no coefficient, we leave the equivalent section untouched (the default value is 1). Now we can calculate the amount of urea produced by pressing "evaluate". If the result is 40.069389 then you have understood how to use this organic chemistry calculator. If not, re-read the tutorial and do exactly as told because I consider this tool very interesting and useful.

ChimeXpert International Chemistry Contest

Hi there again! A few days ago, as I was talking to one of my friends, Victor (he also went to the same chemistry contests as me) on Yahoo Messenger, I realised that the registration phase for ChimeXpert International Contest has recently begun.

Chimexpert is an International Chemistry Contest, organised by Romania and hosted by Satu Mare every year. Up until now, students only from Romania, Italy and Hungary have participated, but this year the organisers intend to bring contestants from other countries too, so all and sundry is welcome.

In order to register for the contest you must first fill in an application form online and then pay a 12 euro tax (or 40 RON). You can find more information at the Regulation section, on their website.

About my personal experience with this contest, I can tell you that last year I participated at the International phase and returned home with a III^rd prize (as a result, after the proper competition I made a post about it). It isn't bad my result there, but I definetely know that I could have done better. Hope to see you there at this year's edition!

My Summer Holiday - The Olympiad

It's a while since you last heard from me so let me tell you what I've done all summer long. To start from the beginning, I spent the first half of my holidays at home preparing for the Romanian National Earth Science Olympiad, then I went to the olympiad itself where I did pretty much nothing (but still gained some experience for the next years) and only then can I say that the proper holydays began (one week at Bicaz lake and two weeks in Bulgaria).

Brain Fitness - preparing for the Olympiad

Our holydays began this year on the 15^th of June, as usual. Due to the fact that I was qualified for the national phase of the earth science olympiad, I started my preparation from day one. The contest itself covered 4 major areas of science: geography, physics, chemistry and biology. For each of these disciplines, I had some reference books reccomended by my teachers Lidia Minza (chemistry), Dana Samoila (biology), Ion Cioroiu (geography) and Doru Costache (physics):

• For biology, I have read some chapters focusing on ecosystems, biotope, biocenosis, food chains and more subjects like these, from an ecology textbook.
• The physics covered only mechanics which is good, because it was my object of study at the physics class this year. The recommended book here were "Fundamentals of Physics, Volume 1" (Halliday, Resnick, Walker) and "College Physics" (Sears, Zemansky, Young).
• Geography was a little bit trickier beacuse it implied a multitude of smaller domains such as climatology, hydrology, tectonic plate movement and a little bit of economic geography. Here, the reference books consisted in about 6 texbooks and one pretty old general meteorology course (Stoica, Cristea) for the first year students.
• As for chemistry, the knowledge of basic inorganic chemistry would have done the job.

I know these domains of study do not seem to have many things in common, but it was our job to find connections between them because we had to analyse a problem from multiple views.

The Olympiad

The olympiad took place in Urziceni, a little town in the southern part of Romania. A funny thing about its history is that in the Middle Age it was called "Vai de ei" (translated into english as "Poor them" - well, it seems it is still the case today). So, on the 19^th of July, knowing that we will spend one week counting the hours until returning home, because of boredom (or at least this was what we thought), we packed our luggage and left home. When we arrived, we realised that our accomodation place was a high-school campus almost in the middle of the field, at about an hour away on foot from the town through the crops!... We had a catering room (the food was pretty good), dorms with 6 beds each (for boys and for girls separately), shared bathroom and showers (for both boys and girls - actually this was not bad at all :)) ). To sum up, the accomodation was pretty good with one exception:

A very "cute" cockroach fellow in our bathroom :)) The exams were really tough, combining geography, physics, chemistry and biology and it was very hard to analyse one problem from all perspectives. At the theoretical exam the highest mark was sadly only 63 out of 100. For the practical exam, the organizers took us on a trip to seven different landmarks, in order to observe the chemical and physical processes in each and every of these:

1. the water filtering station (the filtering processes by physical and chemical means should have been observed)
Here were the machines responsible for the first filtering step
2. the waterworks (here we should have kept our eyes on the purification process of underground water extracted from a 35 meters well)
3. the landfill (we should have compared and contrasted the ideal ecological landfill and the current situation of the dump site)
4. a natural gas compressor (here the chemical composition of the gas and the proper physical processing was the entire point of the visit - no photos here because we were put to sign a paper stating that the information unveiled here would remain confidential)
5. a dam over Ialomita river (the dam's functioning system was emphasized)

6. a bridge over the same river (erosion process highlighted here)
The bridge was somewhere in the left - not included in the photo because the purpose of the visit was not the bridge but the sedimantation/erosion processes (you can easily see the newly formed bank of the river as an extension of the land)
7. a field near Urziceni (we should have noticed the subsidence phenomenon happening)

So, from all the conclusions we had to make observing these places, we were given the practical exam. The subjects were not necesarilly difficult, but the lack of time was the major problem. We had about 7 subjects to solve in only 2 hours (and the solution for every subject was about two A4 pages long, so it was indeed a lot). After the exams, because it was very hot inside, we just took out all our matresses outside, in the schools courtyard, and staid awake till about 1:00 AM and only then, eventualy fallen asleep.

A poor quality photo (I'm the guy in green) - just wanted to show you the way we slept that night

But if you consider the life here to be peacefully and quiet, you haven't got the point yet. One night, as it was getting very late (about 1:00 AM) we went on the wrong street when returning home. Suddently, we realised that our route wasn't the good one, but too late, we all forgot the way of coming back. As it was not a good hour for knocking at people doors, we followed our intuition and went directly though the middle of a cornfield to the point where we thought our accomodation place was. After passing a railway line, a group of three weird looking, seemingly dangerous people came out of no-where. They started putting questions about where we were going, for what reason and things like that. Of course, being damn scared (we were only three boys and about four or five girls) we did not respond to them. Seeing no response from us, they started embracing the girls and trying to kiss them, knowing that we were defenseless. After a while they got bored seeing absolutely no reaction from us and left. With them going away from us, we were not only relieved, but we realised what could have happened in the worst scenario. Shall I be again in the similar conditions, I can tell you that I won't do the same thing again, that's for sure. I think you were used with photos from different moments, I know that, but I don't believe this was the right moment for a group picture, eh? :D

In the end, I came the 62^nd out of 85 (shame on me), but I think this year will count as experience for further contests and olympiads of this type.

Because the are so many things still to tell, I'll make two posts, one for each of other the two trips. So, coming soon... Bicaz Lake Trip and later, an All-Inclusive Bulgarian experience. :))

Petru Poni National Chemistry Competition

Last weekend, I went to the national phase of a regional chemistry contest, named after the Romanian chemist Petru Poni. It took place at Onesti, a town near one of Carpathians' mountainous areas. We arrived there Friday morning and came back to Galati Sunday evening.

The contest consisted in a theoretical exam and a practical part, at which I scored 94 respectively 73 out of 100. In the end I won a Mention which is pretty good, though I could have done a lot better.

After the contest we enjoyed a walk in the mountains, we hiked along foot-trails and we saw some beautiful sights. Although it was a rather short trip, we liked it - a little escape from school ;-)

The team of my county on the top of a hill during the walk, I'm kneeling in the middle

To sum up my first high-school year, here are my chemistry results in competitions, so far:

• 43rd edition of the Romanian National Chemistry Olympiad, 1-8 February 2009, Arad - Honorable Mention
• 5th edition of the ChimeXpert International Chemistry Competition, 27-29 March 2009, Satu Mare - IIIrd Prize
• 7the edition of the Petru Poni National Chemistry Competition, 24 May 2009, Onesti - Mention

I hope the summer will bring both fun and better preparation for the next year chemistry competitions.

A redox reaction in ChemLab

A chemistry laboratory isn't accessible to everyone, everytime, so I often use a virtual laboratory: Model ChemLab software (I have just an evaluation version and would be nice to receive some day a full/standard version). It's a pitty to find so few tutorials or resources on this product on the internet, so even the smallest contribution on the argument, counts. That's why my thought was to show some experiments made using this software. Let's compare a typical redox reaction (between KI, H₂SO₄ and oxygen) in the real lab vs. the virtual lab

In the real lab

The unbalanced reaction is:

KI + O₂ + H₂SO₄ → I₂ + K₂SO₄ + H₂O

The installation for making this reaction in the lab

In the Florence Flask we have KI solution. In one of the two tubes that enter the flask through the cork is pumped continously oxygen (or at least air), and from the other is carefully dripped out sulphuric acid. When a dark violet-blue precipitate is observed on the bottom of the flask, the acid stream should be stopped. Immediately after that, the solution will turn dark blue because of the solubilisation of I₂ in the liquid.

In ChemLab

After launching ChemLab, from the ChemLab Simulation Modules dialog, go to the Lab Wizards tab and choose ChemLab Wizard v1.7 (I run ChemLab v2.5 for Windows)

A reaction wizard will appear. Click Next.

Now complete the blanks with the Title, the Description of the reaction and the Author (your name). Then click Next.

The following step is to write the paths to the Introduction, the Procedure and the Observations files. Leave this blank, because it will help you only if somebody else will follow the instructions of the lab simulation you made. Only to mention. these three parts must be in ".RTF" or ".TXT" formats. So, click Next.

Select from the second list (Chemical Database) O₂, KI H₂SO₄, I₂, H₂O, the K⁺ cation and the SO₄^- anion and add them to the Added Chemicals list.

Select Potassium cation (K⁺) item in the first list and press Chemical Properties button. A dialog (Chemical properties:- Potassium Cation) will appar. Here you must follow a few steps:

• Uncheck Stock Chemical, as you don't want to have potassium from the early beginning

• Check Reaction Product checkbox

• Check Flame Test Color, as you will recognize, using a burning droplet of solution, the potassium cation by it's pink-red flame colour.

• From the color list, select the "Other" item:

• A dialog (Color) will appear. Select the pink-red color and click OK

• In the Chemical properties:- Potassium Cation dialog box, click OK

  

For SO₄^2- anion, I₂ and water, uncheck Stock Chemical and check Reaction Product.

For KI, check Solution and in the Molarity field write down 10M, because this is the molarity of the KI solution (pretty concentrated). As for the Flame Test Colour field, select that pink-red colour as earlier.

The same for sulphuric acid, but this time no Flame Test Colour.

Now, there is a little thing you must observe: ChemLab works only with liquids and solids, when talking about reactions. So, although it is practically impossible to dissolve oxygen in water, if we want to work with it, we will be forced to consider oxygen a solution (techlnically it would be possible if we cool enough the gas in order to make it a liquid - but this isn't our case).

All substances being added to the list, press Next.

It's reaction editing time! In order to do that, we first balance the equation by the redox method.

KI + O₂ + H₂SO₄ → I₂ + K₂SO₄ + H₂O

O₂^o --(+4e^-)→ 2O^-2....2.....1 2I^-1 --(-2e^-)→ I₂^o........4.....2

So the balanced reaction is:

4KI + O₂ + 2H₂SO₄ → 2I₂ + 2K₂SO₄ + 2H₂O

Now, that the reaction is balanced, we can start editing the reaction in ChemLab. Right-click on the Reactions node in the Reaction tree and press Add New Reaction.

A dialog will apear. In the Reaction Name field, fill in a name (for example, REDOX), then click OK.

Now, your window should look like this:

Drag one by one the substances from the right list to the left one. The Oxigen, the KI and the acid shall be the reactants and the rest of the substances should be the products.

When you add a substance to reactants/products another dialog is opened, asking about the coefficient of the substance in the reaction and a few other details. For example, for Oxygen put the coefficient 1 and click OK. For KI put 4, for the acid 2, for the potassium cation 4, for the sulphate anion 2, for the water 2 and for iodine it is 2. But when you are adding iodine, also check "In Solution", "Causes Colour Change In Solution" and "Uses Colour range". Don't forget to write down the minimum (0) and maximum (100) concentrations in the Low, respectivelly High fields. Select the blue colour from both two lists.

Now, that all substances have been added, your window should look like this. If so, click Next.

In the lab options window that you are facing now, check Include Metal Wire.

The next frame shows us an Add Indicator option; but because we don't need that now, we will just click Next.

The next frame shows a molecule viewer option. Skip it if you don't have molecular models for these substances.

The wizard is finally ready. All you need to do is to click Finish.

Now don't panic. After clicking Finish, it will show you 3 errors. On each and every of them click OK (these errors are caused by the absence of lab documentation files that we don't need for this demo).

Now we can start the simulation.

1. Take a 100 ml beaker (by right-clicking and then selecting Beaker, respectivelly 100 ml Beaker).

   

   And here it is our Beaker.

   

2. Fill it half with acid (50 ml)
   • Right-click and select Chemicals

     

   • A dialog box will appear. Select the sulphuric acid and as a quantity, type 50 ml.

     

   • The half-full beaker will look like this:

     

3. Fill an other beaker 1/4 with liquid oxigen (25 ml).
4. And an other one with KI (25 ml).
5. Take a big 250 ml Beaker and pour in it first the oxigen, second the acid, and third the KI solution (you can pour a substance into a vessel by placing the substance that will be poured above the vessel, right-clicking on the first container (that will be emptied) and selecting Pour/Decant).

   

6. After pouring the KI solution, the mixture should go dark-blue.

   

Sorry for the length of this post, but I wanted to pass through every step in order to make the entire virtual experiment clear. I'll also try, if you liked this, to make different experiments and describe them in ChemLab.

Bloody Chemistry

As I was at Satu Mare, in the middle of the poster session, I saw a poster with a very interesting topic: fake blood, an application of chemistry in cinematography. When I returned home, I've made a little bit of research on the subject and here it is.

The fake blood effect

Fake blood is widely used in action films, thrillers, horror films and westerns. There are many ways to prepare fake blood but only one of them truly gives the impression of real blood.

• Glassware you'll need: a beaker, a spatula, a watch glass and a hot plate
• Chemicals you'll need:
• Iron(III) Nitrate hydrate

Image from: http://www.huangchem.com/

• Potassium Thiocyanide

• How to do it:

1. Take one 100ml beaker and fill it up with KSCN solution.
2. Weigh about 2 grams of Fe(NO₃)₃ and carefully pour it into the watch glass. Put the watch glass on the hot plate and heat it up to 50^oC (actually 47.2^oC is the dehydration point of Fe(NO₃)₃, but 50 is just fine)
3. Now that the colour of the crystals has turned from intense magenta to light pink (or at least it should have), take using a spatula, a few crystals from the watch glass and put them into the KSCN solution
4. Now you should observe a deep crimson red colour in the solution as the result of the reaction

Fe(NO₃)₃ + 6KSCN → 3KNO₃ + K₃[Fe(SCN)₆]



Image from: http://www.buffalostate.edu/

• Although it's sister K₃[Fe(CN)₆] is highly poisonous, this compound represents no threat to human health, so it is used in the film industry as blood which stains skin or in solid form it is used to imitate scars and so on. In western scenes you often see gun shots like they were true but in reality it's just a balloon full of K3[Fe(SCN)6] that will make you believe the bleeding is real.

Hope you aren't scared of that guy up there :)) It's just K₃[Fe(SCN)₆], you know!

Excessive water drinking really makes people fat?

Some of you may have known that excessive water drinking makes you fat. Well, nutritionists and anatomists have been (and still are) in a continuous dispute on this topic. Personally, I consider this subject to be very interesting, because at a first glance the subject seems paradoxical.

What do nutritionists say?

Technically, water has no calories, so you can't deposit any of it's energy because it hasn't any (I remind you that this is energy from the burning of the nutrients). Its only use in the organism is that of being a very good transportation environment in the form of plasma in blood (blood plasma is more than 90% water):

• It won't react with any of the nutrients that the organism needs
• It is a polar substance that can dissolve all polar compounds and can transport as a suspension the apolar ones that won't normally dissolve in it.

So there would be theoretically no chance for you to get fat. Even more, if you drink cold icy water at 0^oC, your body has to warm it before putting it in the circulatory system. So 100g of water will consume 2 Cal, which means that it will even make you thinner (of course somewhere around zero point zero and a little bit grams, but hey it's weight loss wright? :)) )

What do anatomists say?

Except of the fact that water makes us gain weight simply by the weight of the water itself, there is a more profound explanation to be found at a much smaller scale, the cell level.

It is known that a cell's membrane is a phospholipidic three layered tissue which is composed from membranous units. A unit has both a hydrophobic and a hydorphilic head. This maintains a constant concentration in water of the cytosol between 60-70% as far as I can remember from biology classes. When the concentration in water of the cell belittle under these values, some proteic tubes are opened in order to let the water in. The same happens when the difference between the outside and the inside is pretty significant (the outside is richer in water in this case).

If a person drinks a lot of water regularly, the blood plasma will be always very rich in water, so cells will receive continuously water, until the interior concentration will equal the exterior concentration. Like a rubber gum, if maintained elongated for a long time, the cell membrane will lose its elasticity and suffer plastic deformation. From this point, the cell membrane can't regain its initial shape and will occupy a larger volume. That's the story for a single cell. But when the measuring unit is several billion cells ( around the number of the cells in the human body) they will have a considerably bigger volume, and will give the impression of a fat person.

So, next time don't put the blame on hamburgers for all the fat. Blame water :)) !

ChimeXpert International Contest

Last weekend I participated at the 5th edition of the ChimeXpert International Chemistry Competition, which took place this year at Satu Mare. Even though I've obtained a III^rd prize, I am pretty disappointed with this result because I was really close to the second prize. The competition itself consisted in two parts: a three hour written test and a poster presentation in no more than three minutes. I chose the carbon nanotubes as topic for my poster, a fascinating subject that I have researched browsing these books as much as my understanding level allowed me: "Understanding Carbon Nanotubes: From Basics to Applications" (an advanced book, but full of applications; this book helped me to form a practical perspective on the argument), "Science of Fullerenes and Carbon Nanotubes: Their Properties and Applications" (it talks a little about nanotubes but describes very well their special properties) and "Handbook of Carbon, Graphite, Diamonds and Fullerenes: Processing, Properties and Applications" (it helped me figure out how carbon nanotubes are produced).

And now, some photos from the competition:

Me coming through the hallway

All seven of us from Galati county at the official opening of the competition (in the third row)

Hungarian folk dance was a nice show after the opening ;)

The classroom where I sit the written test (I am in a white shirt in the back of the photo)

Me and my poster

After the competion, in our hostel-like room

After two days of competition, 1000 km from home, we returned to Galati. It was pretty nice that everybody from our county returned with a prize, whereas contestants from other counties returned home empty-handed. Lucky us!

Romanian National Chemistry Olympiad and ChimeXpert

Hi! In the last three weeks I hadn't much spare time because I've participated in two chemistry contests, one of them being the Romanian National Chemistry Olympiad, from where although I've returned with an Honorable Mention, I still can feel that I could have done better.

The team members from my county (all seven of us) in front of the Palace of Culture in Arad, just after the ending ceremony (I am at the leftmost).

The other is ChimeXpert, an international chemistry contest (well, just Romania, Hungary and Italy will participate this year) in which I've qualified for the last phase, the international one. It will take place on 27-29 of March, in Satu Mare. Here I will take a written test that is worth 60% of the total mark and I'll have to present an original paper about applied chemistry (this part values 40% of the final score). So for this, I'll research for some interesting information and definitely try to use some creativity.

The Manganese Rainbow

As you may well know, manganese salts are generally black or gray. At the first sight manganese salts do not appear to be very interesting. But at a closer look, this element won't appear so boring. Actually, I can easily say that this is one of my favourite elements for some of its particular reactions. Yesterday, while illustrating redox reactions, I had the opportunity to make one of manganese's most fascinating experiments.

The first two attempts went totally wrong, and when I was on the verge of succumbing my positive state and just give up, the farewell try went just marvelous. It's a very coloured experiment that you definitely shouldn't miss.

Glassware you need: one 100 ml cylinder; one 600 ml beaker; stirring rods; a burete.

Chemicals you need: 500 ml NaOH 6M; H₂O₂ 0,1% (you can obtain it by dissolving 1 ml of pure H₂O₂ into 350 ml water); CH₃COOH 6M; 0,05 g of KMnO₄ dissolved in 1 ml of water and ice

How to do it: in the NaOH solution chilled at 0^oC the entire quantity of permanganate is dissolved. Then from the burete 1 ml of H₂O₂ is added under continuous stirring. We can clearly observe now a palish green colour, because of the MnO₄^2- ion. The reducing agent is H₂O₂.

2Mn⁷⁺O₄^-_(aq) + 2HO^-_(aq) + H₂O₂ → 2Mn⁶⁺O₄^2-_(aq) + 2H₂O + O₂

You continue both adding H₂O₂ and stirring the upper layer of the substance until it gets cold blue.

2Mn⁶⁺O₄^2-_(aq) + 2HO^-_(aq) + H₂O₂ → 2Mn⁶⁺O₄^3-_(aq) + 2H₂O + O₂

On the top you should add now the CH₃COOH, slowly and continuously stirring. Around 20 ml would be more than enough. A crimson red colour should be now observed due to the reaction between the hydronium and the trivalent permanganate ion previously formed.

In the end it should look like this:

Tips:

1. Use only chilled NaOH
2. Do not use indecorous proportions of the substances! Follow the gravimetric instructions as close as you can for an accurate result.
3. When you mix, try to mix only the upper layer in order not to spoil the colours.
4. Have fun doing this!

Persil, an inorganic detergent

Hi there again! I have indeed said that I will no longer post until the Chemistry Olympiad, but today while looking at a video about the chemical element Boron, I heard the fact that Persil is an inorganic detergent that has his name inspired from its two main compounds : sodium PERborate and sodium SILicate. So I did a little bit of research on the Internet and may I say that, I've found some pretty worth to mention things.

As I said earlier the two principal compounds of Persil are sodium perborate and sodium silicate. The major role of the perborate, in the washing process, is to decompose at high temperature in the washing machine in the presence of water to form hydrogen peroxide, and a B(OH)₄^- ion. In the next step, the hydrogen peroxide will remove the stains by oxidizing them and making them more soluble into the hot, boiling water.

A little bit of History Before the first world War, there were no detergents commercially available. Women had to wash clothes with house made soap in the water of the nearby river (only rich people could afford their water pumping system).

Image from http://www.hohenstein.de/en/index.asp

So, in 1907 Henkel started to commercialize the first detergent which was named after the two major components. This was to be one of the revolutionary inventions at the beginning of the XX-th century. But its great success wasn't felt immediately. Many people couldn't afford it, and it became popular only after the First World War, because it was widely used to wash the soldiers clothes. So only after that 4 years Henkel could lower the price in order to make it accessible to most of the people.

Original advertising poster

Nowadays, Persil is one of the very few toatally inorganic, commercially available washing products left on the market, that is widely used in Europe; the situation has pretty much changed in the last 100 years.

See you next time!