It actually feels good to write again =)

I've been coming to and leaving this blog a few times already...wanting to write something, but feeling too lazy to write. Contradicting, I know...I guess it's just that there are too many things I wanna say.

My last post was written before I left for the Phillipines, and it's already more than a month since then. Time does fly when you're having fun...=)

Before I left for the Phillipines, I felt a sense of trepidation - it's afterall, something I haven't done before. Yet, at the same time, I felt excited, like I'm going to embark on an adventure of my own, with people I knew I was gonna love all the way.

Now that I'm back home, I felt like that trip was one of the things I will never regret in my life...which is why I am going again - this time as a leader -and boy, am I excited! I know that this time I will learn a lot more and will have a lot more fun. I can't wait!! =D And this time, I promise myself to be wiser in shopping for stuff in Manila (or have more money leftover for the R&R) =P

Right now, I don't have much to do at home. I'm only waiting to fly to India (after I settled my Visa and all the other mind-boggling stuff of course). I wonder what adventures would be awaiting me this time. India feels like a place full of history, sights and smells...=P I hope I will still smell normal and have my sanity intact when I return to Singapore.

While I'm waiting to fly to India, my boyfriend is waiting to fly to Shanghai. I kinda envy him, cause I love Shanghai 'Xiao Long Bao' and I know he's gonna get lots of those there! I wish they have mail-order 'Xiao-long bao' for when I've had enough of curries and chapattis. Ah well, I suppose I'll have to resort to cooking for myself when I'm craving for proper chinese food (so glad I can whip up simple dishes. My interest in cooking finally paid of!) cause I heard that the Chinese food in India is way expensive and are somewhat Indian-ised to suit the local palatte.

And, I'm going to Penang on a short trip in like a couple of days...and I know that time will fly even faster =( I really can't wait, and if there is a way to freeze time, I would.

I think I'm getting a haircut tmr. It's getting too unruly for my liking. =X

What do I do everyday? I'm watching 'bamboo blade'. It's a pretty cute anime. I've missed weeks of 'One Piece' and 'Hitman Reborn', not to mention 'Bleach'...I'm way behind time. Sigh...I wish I have at least a wireless connection here, but beggars can't be choosers huh?

Ok...that's all for today...I'm gonna go have some 'dim sum' =) Oishii...

I guess for now, the tempation of food is greater than that little voice in my head which keeps going on about how I'm gonna get fat. I'll worry bout that later. Besides, I'm certain I'm going to get thinner in India (boy, I'm really good at rationalising and making myself feel less guilty)..=P

See ya!!

Desires and Happiness

Desires are like a big vicious cycle. The more you want, the more you will want MORE. There is nothing such as a rich man who will say 'no' to more money...even though he already has plenty. They will always want MORE...more happiness, more clothes to choose from, more of everything.

And so, people pursue what they want to have relentlessly, sometimes forgetting that what they have now, is probably what they've only dreamed of in the past.

In this pursuit, I suppose people do not 'satisfice'.

Of course, things people pursue can be wealth, recognition, acceptance, or fame...but actually, we are all only pursuing one thing - HAPPINESS.

But actually, happiness can be simple...

Isn't it so?

Something which I HAVE to say...

I read with shock about the Phillipines massacre. While I was struggling with my exams and hoping it would be over, these people were fighting for their lives - to no avail.

The worse part, I feel, was not the killing...but the reasons behind it. Apparently they were for political reasons, and all who were killed were extremely innocent people - journalists, passersbys, and women. The news left out a lot of details, but I think that the killings were gruesome. Who knows, maybe some of the women were even raped.

The Phillipines is definitely a country which is now suffering from misfortunes. First, it is the typhoon, then more typhoon, then this mindless massacre (and the ongoing terrorist activities in the south). I wonder how the Phillipines as a nation would be able to recover....or even how the family and friends of those who were killed (literally executed) would be able to accept it.

It is such incidents that made me feel that politicians become politicians for the money, fame and power; and not because they truly would like to help their own people. While children are educated in patriotism and such, the leaders of the country are in fact the ones who are the least patriotic. Shame on them...

At the same time, I do feel that if the perpetrators are doing this for political purposes, they have just done the opposite. They have just ruined their political careers...good for them...

I truly pray that the perpetrators would be brought to justice (not only those who carry out the dirty act, but the masterminds too). If they are capable of carrying out such horrible acts, it shows that they have lost their humanity, and as such, they should not be treated humanely. I am not an advocate of the death sentence (and in fact, I feel that it shouldn't exist), but for some people who are worse than animals (at least animals kill each other for food), may God forgive them, cause I doubt that humans will be able to.

I also pray that the victims might rest in peace, and that their family and friends would be able to recover someday. Although they say that time heals, I doubt that it would in this case...but I still pray that somehow they will be able to survive this tragic incident.

Hemostasis - the blood clotting cascade

The blood cloting cascade relies on pre-existing zymogens in the blood. Each activated blood clotting factor is essentially a proteolytic enzyme which activates the next zymogen in the cascade.

There are 2 main pathways (extrinsic/tissue activating, and intrinsic/contact activating) which culminates to a common pathway (whereby prothrombin is converted to thrombin, and fibrinogen is converted to the insoluble fibrin).

The extrinsic pathway - ends with the activation of Factor X (begins with tissue damage)

When tissues suffer trauma, tissue factors are released (tissue thromboplastin/Factor III). This reacts with Factor VII and Ca2+ to activate Factor X.

Factor X cannot be activated merely by this pathway, and requires activation by the intrinsic pathway as well.

The intrinsic pathway - ends with the activation of Factor X (begins with endothelial damage/exposed collagen/contact with foreign surfaces)

The intrinsic pathway requires Platelet factors (PF3) - a phospholipid.

When the blood is exposed to a foreign surface, or when there is damage to the blood vessel, Factor XII is activated.

Factor XIIa activates Factor XI.

Factor XIa activates Factor IX (with the help of Factor IV and Ca2+).

Factor IVa activates Factor X (with the help of Factor VII and Ca2+)

The common pathway - begins with activation of factor X

Factor Xa catalyses the change of prothrombin (factor II) to thrombin.

[in the presence of Factor V, Ca2+, PF3)

Thrombin has 2 roles:

• Change Fibrinogen (Factor I) to Fibrin
• Activates Factor XIII which stabilises the fibrin meshwork to form a stable clot.

The common pathway ends with a clot formation.

Several cofactors which are important are as follows:

1. Vitamin K - Required to activate the precursor zymogens as it helps in the formation of Ca2+ binding site. [ 'glu' components of glutamyl to 'gla' components of g-carboxyglutamyl]
2. Calcium + phospholipid - required for the binding of Factor Xa and prothrombin. Platelet phospholipids have negative charges which attracts Ca2+ to bind. 'Gla' components of Factor Xa are attracted to these Ca2+, and concentration of Xa builds up. At the same time, concentration of prothrombin (also has 'gla' components) also builds up. Factor Xa and prothrombin are brought to close proximity, starting the common pathway.

Fibrinolysis follows....which is the dissolution of blood clots by plasmin (which is formed from plasminogen whihc is already present normally in blood). Products of the dissolved blood clot is removed by phagocytic WBC.

[ plasminogen (from liver) is converted to plasmin with the help of tPA (tissue plasminogen activator)]

Complement System of the Innate Immunity

WARNING : You do not have to read this post!! (Nobody sane enough should)

There are 3 distinct pathways of the complement system : The classical pathway, The Mannose-binding Lectin (MBL) pathway and the alternative pathway. The classical and MBL pathways are similar. All pathways converge in the production of a C3 convertase (which cleaves C3 into C3a and C3b).

Functions

The complement system eventually produces activated complement molecules which carry out 3 main functions:

1. C3b - Opsonisation [binds Complement Receptor 1 (CR1) of macrophages/neutrophils] to enable phagocytes to recognise pathogens, and in the presence of C5a, phagocytose them.
2. C5b - Begins the 'late' stage complement cascade which ends with the formation of membrane attack complex (MAC), which forms pores in the membranes of bacteria to kill them.
3. C3a, C4a, C5a - anaphylatoxins; C5a most active. They mediate inflammatory response (eg: increase vascular permeability, stimulate endothelial cells to produce adhesion molecules, activate macrophages to ingest pathogens)

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The Pathways - up to the C3 convertase

The classical pathway

This pathway begins with the C1 complex (C1q:C1r:C1s) binding to the surface of the pathogen cell or the Fc region of the antibody (which carries an antigen on its receptor).

This causes the C1r:C1s conformation to change. The autocatalytic activity of C1r is activated. C1r cleaves C1s and activates it. C1s is the serine protease of the classical pathway.

C1s cleaves C4 into C4a and C4b. C4a is released. C4b binds to the surface of the pathogen cell (C4b which fails to bind are hydrolysed).

C2 binds to C4b, and becomes susceptible to cleavage by C1s. C2 is cleaved into C2a and C2b.

C2b is released while C2a remains attached to C4b.

The C4bC2a complex is the C3 convertase.

The MB-lectin Pathway

This pathway begins with the binding of the MB-lectin to sugar/mannose residues on the microbe cell. (The residues must be of certain orientation/distance)

This binding causes the MASP2 (MB-lectin-Associated Serine Protease) which is in a complex with the MB-lectin receptor and MASP1 to be activated. MASP2 is the serine protease of the MB-lectin pathway.

MASP2 cleaves C4 into C4a and C4b.

The rest of the process, up to The formation of C3 convertase is similar to that of the classical pathway.

The alternative pathway

The alternative pathway is different from the above 2.

It begins with the spontaneous hydrolysis of C3....forming C3(H20)

C3(H20) binds factor B which is cleaved by factor D. Factor D is the only non-zymogen in the complement system (which means it is present as an active enzyme...not as a precursor).

B-----> Ba + Bb

Factor D is the serine protease of the alternative pathway.

Ba is released. Bb remains bound to C3(H20) to form C3(H20)Bb, which is a fluid C3 convertase.

C3(H20)Bb cleaves more C3 into C3a and C3b. C3a and C3b binds to the surface of the pathogen.

The surface-bound C3b binds Factor B (which is cleaved again by Factor D). While Ba is released, Bb is bound. C3bBb is the C3 convertase formed from the alternative pathway.

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What happens after C3 Convertase is formed?

The function of C3 convertase is to cleave C3 into C3a and C3b.

C3b can either act as an opsonin, or it can bind C3 convertase [ C4bC2bC3b/ C3bC3bBb] to form the C5 convertase.

(In the alternative pathway, C3b can also bind to more Bb to form more C3 convertase)

C5 convertase cleaves C5 into C5a and C5b. C5a is released (anaphylatoxin) while C5b binds C6 to begin the production of MAC.

C5bC6 complex then binds C7, and it attaches itself to the cell surface of the bacteria.

Then C8 is recruited to the complex. C8 inserts into the membrane of the bacteria.

Next, C9 is recruited, and begin to polymerise to form the MAC which is essentially a pore in the bacterial membrane. This disrupts the lipid bilayer and destroys proton gradient, and eventually kills the bacteria.

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Control of complement system - prevent attacking host cell.

The complement molecules (apart from Factor D) exist as inactive zymogens which require cleavage (by a previous activated zymogen in a cascade) in order to be activated.

Most of the complement molecules are rapidly deactivated if they are not bound to the pathogen cell membrane.

The host has an array of regulatory substances which helps to deactivate complement molecules (even if they do get activated). These are not possessed by pathogens. In fact, pathogens possess the P factor which has a positive effect on the C3 convertase complex (C3bBb).

1. C1 Inhibitor (C1IN) - Removes C1r + C1s from C1q
2. MCP (Membrane cofactor of Proteolysis), DAF (Decay accelerating factor), CR1, C4BP - displaces C2a from C4bC2a complex (C3 Convertase); and the C4b is cleaved into the non-active C4c and C4d. (In alternative pathway, these molecules displace Bb from C3b. C3b is cleaved into iC3b by I factor)
3. MCP is a co-factor for I Factor.
4. C5 convertase inhibitor - Cr1 and H factor displaces C3b from C4bC2bC3b complex. C3b is also cleaved into iC3b by I factor (H factor is the co-factor)
5. MAC inhibitor - CD59 stops the assembly of MAC between C8 and C9.

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Sigh~~ I don't even know if this is gonna be asked...=( But i hope so!!!

It's gonna be a long week ahead...

The longest week in the entire semester - the reading week...

I've just watched the newest episode of 'Katekyoshi Hitman Reborn' =) Was really nice...Yamamoto's passion for baseball and for his friends is really admirable to say the least. And as usual...Lambo is really adorable =P

http://www.watchanimeon.com/kateikyoushi-hitman-reborn-episode-159/

here's an image of Lambo: Isn't he adorable? lol!

By accident, I found this totally cool cosplay site: The costumes and makeup are really almost identical to the anime. Very cool!!

I really like the 'chrome dokuro' one...

http://letscosplay.blogspot.com/2008/03/katekyo-hitman-reborn.html

I haven't watched 'the big bang theory' for ages now...But it's currently my favourite comedy. At least the jokes are not stupid...

My best friend is in Taiwan...wish I could be there too...heard that the market there really rocks! But I wonder if stuff are as cheap as in the market I went to in Bangkok - Chatuchak weekend market. Until now, I still wish I had brought more cash...lol!

Hope she'll have an amazing holiday there...=D

Just a thought...

I suppose it is true that the only thing unchanging in this world is 'change'...but...there are some things that will never change, and you know it.

LOVE...different people may fall in love, or fall out of love, or they can love in different shapes and sizes; love can be from friends, parents, teachers, or anonymous passersby, but love is a constant in this world...and with love..there is..............

HOPE...there is always hope on earth...no matter how bleak it is. And I suppose...nobody ever really stops hoping.

MUSIC....no matter what kind, there has always been music. It can be pop, rock, jazz, classical, tribal, or even the little birdy chirps, the cricket songs, the pitter-patter of raindrops (which I've been hearing all day), or the sound of the person you love breathing (or snoring) next to you.

SMILES....I guess that this is the most universal language among humans, and on earth. If you look carefully, animals smile too...maybe not with their lips like we do...but I feel that the wag of a doggy's tail is a smile too=)

BEAUTY...it is in the eyes of the beholder...and it is up to you to see beauty in anything or in any situation. But beauty has always been there...

and many many more....

Do I need to tell you that I L.O.V.E all the above? =P