Tag: Scitech

Sorry to be late tonight.  I was occupied earlier this afternoon than I had planned and got a late start.  However, I wanted to produce a quality piece even though it did not post exactly at 9:00.

This the last part in our three piece series on anesthetics.  We have covered general anesthetics of the inhalation type and of the IV type, and now will discuss local anesthetics.  The primary difference betwixt general and local anesthesia is that in general anesthesia the patient is generally unconscious or at least highly sedated, whilst in local anesthesia the awareness of the patient is generally not impaired, although sometime they are sedated by other agents.

The term “local” is not as descriptive as one might think.  While it is true that very small areas can be anesthetized, often much larger areas are.  By the way, it is likely that local anesthesia is much more ancient than general anesthesia, for reasons to be explained later.

Last week we started this three part series with inhalation anesthetics, and here is a link.  This week we shall discuss injected anesthetics, and finally shall finish up the series next week with local ones.

We should once again stress the difference betwixt anesthetics and analgesics.  In general (this rule is not 100%, but darned close), anesthetics render the patient unconscious so that surgical procedures can be performed with no physical pain during the procedure.  In addition, many anesthetics cause muscle relaxation which makes surgical procedures less traumatic.

Analgesics, on the other hand, are not designed to render the patient unconscious, but rater to moderate the sensation of pain caused by many reasons.  A few analgesics can be used as anesthetics, but in general depress the medulla such that respiratory difficulties often result.  

Anesthetics are as essential to modern surgery as are sterile fields and antiseptics.  There are a couple of reasons for that, the most obvious being that the patient most likely could not survive the shock and pain of any but the least invasive procedure with out them.  Interestingly, the use of anesthetics in the modern sense is quite recent, dating only from the mid 1800s.

There are two major divisions of anesthetics, general anesthetics and local ones.  General ones cause a more or less complete loss of sensation and consciousness, whilst local ones cause a loss of sensation for only a relatively small part of the body and leave the patient conscious.  In addition, general anesthetics fall into two wide classes, inhalation ones and intravenous ones.  We shall discuss, in general terms, inhalation general anesthetics tonight.

One metal that we take for granted is tin, something that most of us see and handle every day in the form of “tin” cans, long used to store food.  Actually, this invention dates only from the early 1800s when canning itself was invented, although tin plated iron and steel date back much earlier.

Tin is used it lots more than cans, however.  Much of the tin used today is in the form of solder, used for joining other metals, particularly copper and brass, together.  Formerly a 1:1 by mass mixture of tin and lead was used for soldering copper water pipes, but because of increased awareness of the dangers of lead, other solder compositions are now used for potable water.

Let us take a few minutes to explore this interesting metal.

Human Papilloma Virus (HPV) is one of the most common viral infections in the population.  HPV causes nuisance conditions such as common warts up to deadly cancers.  Some estimates indicate that essentially all cervical cancers are caused by various strains of HPV.

There are very many strains of HPV, most all of them highly contagious.  Let us spend a few moments discussing this important group of infectious agents.  Before we get started, let me make it clear that this discussion will be frank and might seem to be extremely graphic to some.  That is just the way it is, and to water down the content would not do a service to anyone.

When the term yeast is used, most people think of freshly baked bread.  Many people will also think of a cold, foamy headed beer.  Both are made possible by yeast, but there are many more applications.

Yeast has been used to raise bread and make beer and wine since prehistory, and the work is very ancient.  It comes to us in modern English via the Old English gyst, which in tern derived from the Indo-European word yes, meaning quite literally to bubble.  Thus the word is very much older than our understanding that yeasts are living things, dating from the 1850s due to the work of Louis Pasteur.

When we think of yeast, we normally are referring to a single species (out of around 1500, give or take), Saccharomyces cerevisiae.  This single species is responsible for raising bread, making wine and much of the beer that is drunk, as well as alcohol for beverage and industrial purposes.  Unless I qualify, when I use the term “yeast” this is the species to which I refer.

I was running out of time last week as the publication hour was neigh, so I was not able too include everything that I wanted to include.  In the meantime, I have gained some additional information that refutes one of the points that I made.  Remember, The Geek likes to be corrected when he is wrong.  We shall get to that after the fold.

This installment has to do with some experimental or otherwise not widely used loudspeaker designs, but also something much more personal to me.  It has to do with a good friend from almost 40 years, and his interaction with Paul Klipsch and others involved in the company.

First we shall make the correction, then talk about other loudspeaker designs, and then the more personal stuff.  Ready to go?

In electronics, a loudspeaker is what most people just call a speaker, the device that converts electrical signals to sound.  They can range from very simple to very complex designs, with variations in cost from just a few cents to thousands of dollars.

All practical loudspeakers are electromechanical devices, using an analogue electrical signal to make the loudspeaker components to move in such a manner as to in turn move air (usually, although other media can be used for purposes other than human perception) and thus make a sound.  For human hearing, air is almost always the medium used.

Loudspeakers are one of the few modern electronic devices that are analogue only.  In other words, a truly digital loudspeaker does not exist except in a few research laboratories and they are not very good.  It is interesting to me that the final stage of reproducing sound is firmly rooted in the 19th century insofar as basic technology in concerned.  This discussion is limited to electromechanical loudspeakers.  Purely mechanical ones are much older than electromechanical ones.

Before we get started, let me be clear that any information contained here, although to be best of my knowledge accurate, in in no way intended to be a substitute for advice and care from licensed medical professionals.  OK, disclaimer stated.

Aspirin is one of the first synthetic drugs, and is still in wide use after over 100 years.  It was first marketed by Bayer in 1899, and sales are still strong despite competition from drugs like acetaminophen,  ibuprofen, and naproxin sodium.  Bayer has in the past week or two come out with a new advert about its new “quick acting” aspirin.

This material is “quick acting” because the particle size is much smaller than that of regular aspirin.  Since aspirin is only slowly soluble in water, the greater surface area for the same mass does speed up absorption.

I have written pieces about fireworks in this space for several years now.  This year is no different, but instead of describing how modern fireworks operate, we shall, courtesy of The Doctor, take the TARDIS back to 1784, the first Independence Day after ratification of the Treaty of Paris, so for the first time the United States was a truly independent Nation on 04 July.

Unfortunately, my video camera was not working at the time, so I shall have just to describe what fireworks looked like at the time.  The Doctor told me that he would come again and that we would go to the 1785 one for next year, and make sure that I had a functional video camera.

Except for color, fireworks in that era were similar to some of the least advanced ones that we have today.  The complex aerial effects are quite modern, bright color is modern, and set pieces are also modern.