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Comment Re:Got ED? (Score 1) 63

woah, you're totally right. my professor screwed that one up. we were taught that PDE5 cleaves both cAMP and cGMP, but it looks like only PDE1, 2, and 3 cleave both.

the downstream effects would be almost identical though. both cAMP and cGMP cause myosin light chain kinase to be phosphorylated by their respective kinases (PKA and PKG), leading to lower myosin activity and thus relaxation.

nice catch!

Comment Re:Got ED? (Score 1) 63

that's semantics.

in the context of what the poster was saying, i was pointing out that it is arteries that serve as conduits for blood that is flowing toward the penis (and all other tissues of the body), and veins are what serve as conduits for blood flowing away from the tissues.

thanks for your deep insight though.

/medical student

Comment Re:Got ED? (Score 3, Informative) 63

1) veins don't deliver blood, arteries do

2) the relaxation I was referring to was of the smooth muscle in the walls of the arteries leading to the penis

3) there isn't much regulation of bloodflow that takes place on the venous side (ie venous drainage is relatively constant). thus if you increase flow inward it will necessarily lead to pooling (ie erection)

the classic ED drugs all work by relaxing the arteries that flow toward the penis by inhibiting PDE5, a phosphodiesterase predominantly found in penis arteries. this increases cAMP levels, leaving to vasodilation and an erection. unfortunately these drugs aren't perfectly specific, and cause small amount of vasodilation throughout the body, along with a corresponding drop in blood pressure. this is why they tell you not to take the ED pills if you take other vasodilators like nitroglycerin.

if you could engineer a Gs (i was wrong in my earlier post when I said Gi, you want more cAMP not less) receptor that was light sensitive, and get it to express only in the penis artery smooth muscle.... and shine light through your skin to activate these receptors, it would work the same way.

obviously not an ideal way to treat a disorder. these light gated channels are probably only good for basic scientific research.

Comment Re:Got ED? (Score 1) 63

actually, it totally could work. erections occur because certain smooth muscle in the penis relaxes, allowing blood to flow in the right places. ED drugs block the degradation of a chemical that promotes this relaxation. a light gated receptor of the proper type (Gi) could be designed to do the same thing.

Comment Wrong way to go about it (Score 4, Insightful) 162

If you are trying to find a mentor in any scientific field, you don't go looking for "lists" of interests. I don't even know what that refers to. You find recently published primary literature in areas you have interest in, and speak to those authors. This helps you find people who are actively working in the field you seek to be a part of. Even if the authors themselves aren't right for you, they are more likely to know other people in the field than anyone else.

Frankly, I'm kind of shocked. You are applying to PhD programs, but don't currently know any scientists in the field? What about at your undergraduate institution? How did you get interested in social science without reading any papers?

Comment Supernova searching (Score 1) 398

I would recommend looking into supernova searching. As an undergraduate, I worked in a lab that used a robotic telescope high in the mountains to automatically search for these extremely bright and relatively common phenomena. Given their brightness and longevity, it is relatively simple (in astronomical terms) to design and build a system to look for these objects. check out KAIT, the telescope I worked on.

Comment IR vision (Score 1) 157

I took a high-level bio class at UC Berkeley this past semester that concerned exactly this type of genetic therapy. someone brought up the idea of doing this to normals with the pit viper IR heat-sensitive ionic channel gene, tie it to some downstream color of choice.

sign me up.

Comment wrong paper (Score 4, Informative) 157

after a quick look at the paper linked in the article (Identifying photoreceptors in blind eyes caused by RPE65 mutations: Prerequisite for human gene therapy success), it is clearly not about gene therapy in humans. it is a study of the thickness of the retina in humans homozygous for a mutation in a specific retinal gene. as the title says, it is a prerequisite for gene therapy.

the actual paper, Human gene therapy for RPE65 isomerase deficiency activates the retinoid cycle of vision but with slow rod kinetics, can be found here. It concerns the same gene, incidentally.

Submission + - Pirated Copies of 'Splatterhouse' Hit the Net (

An anonymous reader writes: Say you came into possession of a game six months before its release. Would you play it? Sure, most would. You'd probably tell your friends and maybe even blog about it. But given the no-tolerance attitude towards leaks who in their right mind would try to publically sell copies to the world at large? If the game is Namco's Splatterhouse, it seems that one person would.

WorthPlaying writes, "He did not say if the version of Splatterhouse purportedly up for sale was the version developed by the now-defunct Bottlerocket or the version that was retooled by Namco Bandai's Afro Samurai team after it brought the project in-house in February 2009. To prove that he was in possession of a copy of the game, dulledblade also posted a number of screenshots from the unreleased title; each one showed an image of the game and bore a post-it note with his name."


Submission + - Contest - Bruce Schneier seeks new TSA logo (

An anonymous reader writes: TSA Logo Contest
Over at "Ask the Pilot," Patrick Smith has a great idea:

Calling all artists: One thing TSA needs, I think, is a better logo and a snappy motto. Perhaps there's a graphic designer out there who can help with a new rendition of the agency's circular eagle-and-flag motif. I'm imagining a revised eagle, its talons clutching a box cutter and a toothpaste tube. It says "Transportation Security Administration" around the top. Below are the three simple words of the TSA mission statement: "Tedium, Weakness, Farce."
Let's do it. I'm announcing the TSA Logo Contest. Rules are simple: create a TSA logo. People are welcome to give ideas in the comments, but only actual created logos are eligible to compete. (When my website administrator wakes up, I'll ask him how we can post images in the comments.) Contest ends on February 6. Winner receives copies of my books, copies of Patrick Smith's book, an empty 12-ounce bottle labeled "saline" that you can refill and get through any TSA security checkpoint, and a fake boarding pass on any flight for any date.

EDITED TO ADD (1/6): Please leave links to your submissions in the comments, and I will add them to the post. After the contest is over, I'll choose five finalists and post them. The winner will be chosen by popular acclaim.

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