GDG

Hmm, possible... With most non-retroviruses, you really don't expect to see radical mutation within the same host. The flu that you catch from your kids is the same flu that you pass on to your co-workers, etc... Again, possible, but would take some real digging to find a situation that would be plausible. Here's a rough sketch of what happens in infection: Virus enters the host: most frequently, through inhalation, but also through ingestion, sexual transmission, or by contact with a wound (the skin is otherwise a pretty good protection against viruses) Virus latches onto host cell: typically, some part of the virus capsid specifically binds to a target protein or carbohydrate found on the outer membrane of the target cell. Virus enters host cell: sometimes, just attaching to the host cell protein causes it to be internalized, along with the attached virus. In some, like HIV, attachment leads to fusion of the virus membrane with the host cell membrane, and release of the virus contents into the host cell. Virus hijacks host cell: this varies from virus to virus. Retroviruses are reverse transcribed into DNA, which inserts into the host genome, and then gets transcribed and expressed as if it were host proteins. Other viruses are directly translated by host ribosomes (for RNA viruses), or transcribed and then translated (for DNA viruses). The virus typically also has a protein or two that suppress antiviral measures, and shut down or minimize the cell's normal transcription and translation of its own proteins. At this stage, the host cell will also take fragments of the viral proteins, stick them into MHC proteins, and present the MHC+viral fragment on the host cell surface. MHC ("major histocompatability complex") proteins are proteins that your immune system recognizes: when a lymphocyte encounters an MHC protein with a foreign protein stuck in its binding site, this signals the immune system that there is an infection, and T cells that can recognize that MHC+viral fragment develop. These cells become cytotoxic T lymphocytes (Tc cells), and go around destroying cells that are displaying that MHC+viral fragment on their surfaces. Virus replicates: the virus, using the host cell's machinery, makes multiple copies of itself. Virus escapes: the virus may bud out through the host cell membrane, or it may simply keep replicating until the cell bursts open, releasing all of the virus particles inside. Your immune system tries to kill off the infected cells before they can be used to make more virus particles. The infection becomes an arms race, between viruses replicating as fast as they can, and the immune system trying to mature more Tc cells and B cells (making antibodies) as fast as it can. (Incidentally, this is why we have vaccines: once the immune system has been exposed to a pathogen, it is usually much faster to come up to speed the second time it encounters that pathogen.) Virus is transmitted: the virus must pass on to the next host, or you won't have a chain of infection, and the virus will die with your host. Basically, the virus needs to end up packaged in something that will encounter another host, most commonly a biological fluid like blood, mucus, saliva, etc. Back to Step 1. The immune system exerts a selection pressure (think evolution) on the population of viruses. If a virus mutates in such a way that the Tc cells no longer recognize it, then it escapes from surveilance for a while. However, most mutations either (a) do not affect a part of the protein that the Tc cells were using for recognition, or (b) adversely affect the virus's ability to replicate or infect. For example, if the virus capsid protein is mutated so that it no longer binds to the host target protein, the virus can no longer enter the cell, and just gets taken out with the trash. Viruses with impaired replication get out-competed by unimpaired viruses, and by the host immune system. For a virus to mutate from one tissue specificity to another would require that the target proteins be pretty similar, but different, so that altering the virus capsid protein by only one or two amino acids would cause it to bind more strongly to one host protein over the other. Possible, but not very likely. It is possible, however, that the virus encodes several different capsid proteins (or, better, assembles the capsid sequence out of several parts that can be mixed and matched -- this is how your body makes so many different antibodies), and under pressure from the immune system would switch to a different capsid protein. The malaria parasite does something like that to evade the immune system (although, remember, the malaria parasite is many, many times larger than a virus). OK, that's a rough overview. There is a lot more detail, but this is probably already more than you want to read Your local library probably has a few good textbooks on immunology, which would be worth a read to really familiarize yourself with the subject. All part of the background research for a good scifi story Best of luck, Grant

I have a table of frequencies posted on my website, with MIDI note numbers, musical name, instrument ranges, etc. Frequency Table Is that what you were looking for? If you have a MIDI file, you can simply load it into a music notation program (I think Finale has a free version), and look at the notes directly (you can get frequencies off the table in the link above). If you're trying to decode a WAV file, there are programs for this too. I think Finale comes with Autoscribe, which will take a microphone input and transcribe it into musical notation (my guess is that it would also work with a recorded file). I suspect that Autoscribe does not come with the free version... Enjoy, Grant

You may want to pick up a good book on aeronautical engineering first. Yes, the curve of your airfoil will affect the lift generated -- but also the drag, requiring more torque to spin the rotor. Consider carefully the centrifugal forces on your rotor tips when you're going full speed: what happens if a rotor blade fails while spinning at 800 rpm? A: it turns into a javelin traveling at high speed, straight through the house next door, the car parked next to it, anyone standing in the way... You may also want to first familiarize yourself with the federal regulations that govern the design and construction of aircraft by amateurs. The FAA recommends that you take a copy of your plans to the nearest FAA office before you buy any materials or start building. In addition to the regulations, they have a nice advisory circular to help people interested in building their own aircraft. Finally, you may want to seek out your local Experimental Aircraft Association chapter. Best of luck Grant

The densest material found on Earth is found in every atomic nucleus. OK, so it comes in very small packages, not thimblefuls: it's still the same stuff

Nope: the index of refraction is due to the fact that light travels at different speeds in air vs. water, glass, etc. Look at the electromagnetic wave equation, which depends on the electric and magnetic constants for the medium. It is in fact possible to slow light down to a stop. Enjoy, Grant

What kind of bacteria are you testing? There are many, many different species, and there are widely varying environmental requirements and susceptibilities. If your bamboo kills only an innocuous lab strain, and has no effect on more pathogenic bacterial...

"Subspecies" is an interesting choice of terms. I immediately get the sense that these people will be a persecuted group. For most proteins in the body, you're going to have at least a few individuals (if not whole populations) where the protein is already mutated (like those few people who have a different form of CCR5, and thus appear resistant to AIDS). Unless the protein you pick is highly conserved (for example, its function is absolutely essential, and loss of function leads to death), there will be pre-existing members of your subspecies. Not all viruses mutate rapidly: that is a characteristic of retroviruses, which have an RNA genome that gets copied (reverse-transcribed) into DNA after it enters the host cell. The virus reverse transcriptase is fairly sloppy, so errors (mutations) get written into the DNA copies, and multiple strains arise. Most other types of virus mutate (evolve) more slowly, although there are some (like influenza) that also reassort their proteins between different strains easily, which is why we have annual flu waves, and a new flu vaccine every year.

Actually, you probably have a bottle of protons in solution in your kitchen. A hydrogen ion (H+) is a proton, and the distinguishing characteristic of an acid (e.g., acetic acid, the acid found in vinegar) is that it releases an H+ in aqueous solution. Can they be manipulated? Sure. Just use an electrical charge, or a magnetic field, or (in the case of an acid) put them in a bottle. Are they waves or particles? Yes. Both, simultaneously. "Particle" and "wave" are just different approximations of the same underlying reality. Can we do anything with protons? Yep. They're good for making your salad dressing a bit more tart Apart from chemical (and culinary) uses, and their obvious uses in particle accelerators (to study subatomic reactions), I think proton beams are used for microperforating certain materials. Enjoy, Grant

Light actually does travel at different speeds, depending on the material it is passing through. It is the speed of light in a vacuum that is constant (and the absolute limit). So when you open your eyes underwater, you're seeing light traveling at a different velocity than it does through air (or through vacuum, although most of us don't open our eyes in vacuum ). We can rule out the presence of other forms of light using Conservation of Energy, e.g., accounting for the mass balance in a nuclear reaction. Make sense? Grant

The immune system doesn't distinguish between beneficial and otherwise, but between "self" and "non-self" (and sometimes not even then, as in the case of auto-immune disease). Your virus would have to have more than one protein, but it is conceivable that its outer coat protein could resemble a normal human protein (e.g., serum albumin). Also possible that it could simply bind to a common serum protein, effectively cloaking itself in host proteins. However, the antibody system is more effective against bacteria and larger intruders: viruses are also (perhaps mainly) attacked by cell-mediated immunity (killer T cells, natural killer cells, etc.). Yep, if the antibodies were effective, that would work: it is called "passive immunity". When you get a poisonous snakebite, the antidote is antisera (antibodies) collected from horses. However, because the antisera is made up of foreign (horse) proteins, you can have a reaction to the antisera the next time it is administered (at least several weeks later): this is called "serum sickness". You would expect the subspecies to have the same antibody proteins, though, so unless you had some compelling reason for their antibodies to be mutated this would not be a plausible obstacle. Most viruses enter the host cell by binding to a particular protein that sits on the outer surface of the cell. The specificity for that protein is part of what determines which species a given virus will infect, and what tissues in the body will be affected. For example, if your virus targets a protein that is only expressed on liver cells, you have a form of hepatitis. If your subspecies has a different form (e.g., a mutated version) of the key host protein, then their cells would not be infected. This is why people who have a mutation in CCR5 (a cytokine receptor) seem to be immune from HIV, as CCR5 is the primary route that HIV uses to gain access. (Unfortunately, HIV can also use a second receptor.) Toxin release is more of a bacterial ploy, but it would not be impossible for a virus to encode a toxin. Antibodies can be used against toxins too. Toxin release could be a way of obtaining effects in the host other than those caused by the infection of particular tissues. However, keep in mind that most successful viruses are "successful" because their symptoms lead to spread of the disease. E.g., flu and rhinovirus make you sneeze, releasing an infectious mist. BTW, "grippe" was an old name for a disease -- flu, if I remember right. Best of luck with the story Grant

One of the potential applications of stem cells. BTW, the human liver naturally regenerates.

Well, if you're going to implant something in the human body, you need FDA approval first. If it is something inert, you'll have to show that it is safe and non-toxic in humans, and you'll have to implant a sufficient number in a bunch of volunteers and monitor each one carefully for a period of time. Depending on how long you propose the implant is supposed to last, you'll need to prove that it is safe for that amount of time -- i.e., this can take years. If your implant is supposed to have some therapeutic value (not just inert), you also have to prove that it is effective for that, using a statistically significant number of volunteers. It is not uncommon for clinical trials to require thousands of patients, and hundreds of doctors and researchers. The trials required to get a drug approved frequently run US$800 million to over US$1 billion -- regardless of whether or not the trials are successful! This is the main reason that non-generic drugs are expensive, and that generic drugs are cheap (generic drugs do not require clinical trials: just proof that they work like the original drug that they've copied). AFAIK, the FDA does not consider pricing when it approves or rejects a new drug. Its remit is to determine whether or not the drug is safe and effective. As for pharma companies, most prefer to keep their cost of goods down where possible: they won't use gold filaments if they can do the job with cellulose -- there has to be a real advantage other than "costing more." Grant

My guess would be that you're tensing a cranial muscle, and creating enough vibration in the process to vibrate part of the sound conduction apparatus (either your eardrum, or the bones connected to it). I can do that too. You can actually do quite a few things with sufficient practice. One of the early demonstrations for "biofeedback" was to train people to make their hands warmer at will (basically a matter of dilating the blood vessels in the hands). Grant

Hi, I'm Grant. I have a Master's in Chemistry (physical organic) and a J.D., and work as a patent attorney (pharmaceutical and biotech). BTW, patent law is a good field if you have a great interest in science, but would rather write than do labs My main areas of interest are neurology and immunology, and especially their intersection (i.e., neural sensing and control of the immune system, and vice versa). Also cosmology, gravity, and quantum mechanics. Guess that doesn't narrow things down much I can answer general questions about patent law and becoming a patent agent or patent attorney, but please do not expect specific legal advice. Grant