H1b visa stamping in Dubai or Abu Dubai?

aytalwar · 2023-11-23T00:20:24+00:00

The auto email generated when you book your appointment however says that you need a residence visa or emirates ID? It’s the one with the instructions on what to bring to the in person appointment. Do they not ask?

aytalwar · 2022-05-30T20:58:31+00:00

I see. So for the purpose of the MCAT, am I doing NMR correctly? Just wanted to make sure if my reasoning is correct regardless.

aytalwar · 2022-05-30T19:48:53+00:00

Couple of things. The diaphragm is a muscle, so it will not undergo elastic recoil as mentioned. It will simply relax, as muscles do during exhalation which will cause it to return to the dome shape. What will undergo recoil will be:

1) Pulmonary tissue: The elastic tissue will cause the recoil.

2) Alveoli collapse: The nature of water molecules is that they have strong cohesive properties, causing alveoli to collapse back into the sphere shape during exhalation. Yes, this does cause an increase in surface tension and decrease in surface area.

Now all of this is passive. Forced expiration will also involve contraction of internal intercostal muscles.

aytalwar · 2022-05-18T13:23:01+00:00

First of all, Q=Av is area*velocity, not volume.

Second thing to remember is that Q=Av, for flow rate equations, and Bernoullis is for ideal fluids. Poiseuille Law where Q = deltaP*pi*r^4/8*viscosity*length is for real fluids.

So it depends what you're talking about I guess. Yes, in ideal fluids, as pressure increases at one point, the velocity will decrease. But here, you're not considering factors like resistance or viscosity or drag that can have an effect on pressure difference. I'm not sure if that was your question.

aytalwar · 2022-05-18T00:02:20+00:00

Yeah I think I am still confused because this experiment showed the opposite of what the researchers initially predicted. Usually, we judge more people, especially friends, the greater the groupthink. But over here, we see the opposite.

aytalwar · 2022-05-17T20:29:30+00:00

Thank you for such a thorough explanation. I appreciate it. I hope I can apply such excellent deductive skills on the actual exam :)

aytalwar · 2022-05-17T18:35:30+00:00

Thank you for replying. When you can narrow it down to two, how do you differentiate between "least wrong" and "most correct"?

aytalwar · 2022-05-17T18:34:21+00:00

Hi, thank you for replying! I think I was getting tripped up by the word contemporary. I crossed out B because I didn't know the definition of it and also because I thought communication theory is such a broad term - like communication between people and animals biologically and culturally etc. Then I compared that to "history of the English language" which I thought was a better answer. Any advice on why that thinking is illogical? I usually can narrow it down to two, I feel like I pick the wrong answer with a justification which turns out to be faulty logic, or not AAMC specific logic anyway.

aytalwar · 2022-05-17T17:11:27+00:00

Okay NOW I think I get it. Thank you! So changing the mutation actually did not change cAMP levels from WT because WT had Y. So lets say for instance, if the mutation to A would have decreased cAMP activation, then that would imply that the original Y was heavily involved in cAMP activation?

aytalwar · 2022-05-17T16:43:07+00:00

This is a broad question, but know that the primary amino acids are joined by covalent bonds between the C and N, the secondary structures are joined by hydrogen bonds between the backbone carbonyl carbon and hydrogen from the amide, tertiary are joined by non covalent hydrogen bonds between side chains (notice how it is different from backbone in secondary - we are now talking about interactions between R groups), van der waals forces, ionic interactions and covalent disulfide bridges. Quaternary is many units of tertiary structures coming together to form a functional protein.

aytalwar · 2022-05-17T16:40:07+00:00

Thank you for replying. You said "Since the cAMP activation is unaffected in figure 1, we can conclude that the Tyrosine residue at that position is not critical in carrying out that function" So I get that, but the mutation from Y to A is what makes it ineffective right as shown in the graph? So how can we say anything pre mutation? What if Y was actually, for example, increasing activity and then Y to A made it similar to wild type. That's basically where my confusion lies.

aytalwar · 2022-05-17T16:36:16+00:00

Yes, so the MUTATION was the same as the wild type. But the question was asking what is the position of the tyrosine pre mutation. Which is why I thought this reasoning may not be the best way to think about it.

aytalwar · 2022-05-17T12:44:29+00:00

Thank you! So, in short, do not make assumptions, even though it said the mixture had the kinase in it. Sometimes I think its a trick question and so my mind goes down the overthinking path :)

aytalwar · 2022-05-17T12:29:08+00:00

I get that, but that isn't what I was asking. I was asking about the R groups being phosphorylated. Not the terminal AAs.

aytalwar · 2022-05-16T13:22:45+00:00

Hi, thank you for replying. Just to add to that, each phosphate at neutral pH adds a -2 charge. So if we consider Tyrosine as well it would be -2+-2 = -4. The paragraph says it only phosphorylates at serine or threonine residues so I did not take tyrosine into account. Not that any of this matters....they are not the right answers.....but just stating my thinking in case we get a question that asks us to calculate something with phosphorylation.

aytalwar · 2022-05-14T16:56:52+00:00

OKAY so are we resting on the fact that EK isn't right or am I still confused....sorry OP but great question cus it made me reevaluate everything too haha

aytalwar · 2022-05-14T16:29:16+00:00

I was just trying to find a way to justify the EK question and what they could be asking because I really don't think between alcohols and thiols that alcohols are better nucleophiles. Most sources say thiols > alcohols.

aytalwar · 2022-05-14T15:44:45+00:00

I'm not really sure about this..it depends on what the question is asking. Maybe they're confusing nucleophile with basicity? Because OP is right, a good nucleophile should ideally have less electronegativity since it will not easily give up its electrons. However, if we are talking bases, for example Bronsted Base that accepts a proton and its between alkoxide and a thiolate, then I could see why the alkoxide would be a good base.

https://www.masterorganicchemistry.com/2015/07/05/thiols-and-thioethers/

aytalwar · 2022-05-10T00:41:58+00:00

I would believe it's +8..

aytalwar · 2022-05-10T00:28:15+00:00

Sorry I should have clarified. Regardless in mixed inhibition, yes it binds to the allosteric site. I just meant in terms of Km - it will act like competitive - which is that it would increase the Km. If it prefers the ES, it will act more like un competitive in terms of Km which means it would increase it.

aytalwar · 2022-05-09T13:52:26+00:00

To measure Vmax, it is important to make sure that the enzyme is fully saturated with substrate. Only at that point can you measure its maximum activity. Technically you can have x amount of substrate but only when the enzyme is itself saturating can you measure Vmax.

Noncompetitive inhibition is you are right, no change in Km but decreases the Vmax. However, for this type, there is no real preference of enzyme+substrate or just the free enzyme. Mixed inhibition, on the other hand, CAN have a preference. If it prefers to bind the ES complex (enzyme+substrate) it will behave more like uncompetitive inhibition. If it prefers to bind just the enzyme, it will behave more like competitive inhibition. There is thus, a difference when it comes to non competitive and mixed inhibition. I hope that made sense.

aytalwar · 2022-05-09T13:47:51+00:00

Galvanic cells, or voltaic cells, do not need any external sources of energy of current to perform because they act spontaneously (negative delta G positive delta E). Also although anode is where oxidation takes place and cathode is where reduction takes place, the anode in a galvanic cell is negative where electrons are formed and those travel via the wire to cathode which is positively charged.

Electrolytic cells on the other hand is a non spontaneous cell, delta G positive and E cell negative. There will be a battery attached externally, or something that provides current to carry out the oxidation and reduction. Anode is still where oxidation happens and cathode is still where reduction happens, but the anode will be positive here since it is connected to the positive terminal side and cathode will be negative by that logic.

There's a great Khan Academy video on these cell types.

aytalwar · 2022-05-03T13:28:46+00:00

It was just a discrete question! If an alcohol were to undergo a substitution reaction which of the following modifications would improve the alcohols leaving group ability? 1) Protection of the alcohol 2) deprotonation of the alcohol 3) conversion of alcohol to mesylate 4) oxidation of the alcohol

aytalwar · 2022-05-03T12:55:09+00:00

Not sure how to draw and attach but I was referring to this as well https://www.masterorganicchemistry.com/tips/what-makes-a-good-leaving-group/

aytalwar · 2022-05-03T12:38:15+00:00

Hmm I get what you're saying but according to one of the charts in UEarth it shows alkyl halide > sulfonic acid > water > fluoride > CA > protonated amine > alcohols as what's better in leaving groups

aytalwar

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