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2023 March 31

Stress echocardiogram

I have previously reported on my PVCs (premature ventricular complexes) mysteriously turning into SVT (superventricular tachycardia) in Holter monitor results. But when I had an echocardiogram done in January 2023, there were no SVT episodes. The reuslts were that things were pretty much normal:

The patient was in normal sinus rhythm during the exam. The patient had occasional PACs during the exam. The patient had occasional PVCs during the exam.
Left Ventricle: The left ventricle is normal in size. There is mild concentric left ventricular hypertrophy. The left ventricular ejection fraction is normal. The left ventricular ejection fraction calculated by 3D echo is 65%. The left ventricular wall motion is normal. Assessment of diastolic parameters suggests a pseudonormalization pattern, consistent with elevated filling pressures.
Right Ventricle: The right ventricle is normal in size and function.
Atria: The left atrium is mildly dilated. 3D LAVI: 36 ml/m2.
Mitral Valve: The mitral valve leaflets appear to be normal, and opens well. There is no mitral valve stenosis. There is trivial mitral regurgitation.
Aortic Valve: The aortic valve is trileaflet. The aortic valve is sclerotic, but shows no functional abnormality. There is no aortic valve stenosis. No aortic regurgitation is present.
Tricuspid Valve: The tricuspid valve leaflets are thin and pliable. There is no tricuspid stenosis. There is trace tricuspid regurgitation. Unable to estimate PA systolic pressure due to poor TR signal.
Pulmonic Valve: The pulmonic valve is normal in structure and function. There is no pulmonic valvular stenosis. There is no pulmonic valvular regurgitation.
Great Vessels: The aortic root is normal size. The ascending aorta is normal in size. Atherosclerotic changes can be seen in the abdominal aorta. The inferior vena cava appeared normal.
Pericardium/ Pleural: There is no pericardial effusion. There is no pleural effusion.

In discussing the results with the cardiologist, I pointed out that the Zio monitor results (with 2161 SVT episodes in 329 hours, about 6.66/hour) showed clusters of episodes when my heart rate was high, suggesting that they were triggered by exercise.  The cardiologist ordered a stress echocardiogram, to see whether we could catch the SVTs that way.

Today I had the stress echocardiogram test. Here are the stress results:

Protocol Name BRUCE
Max Work Load (METS*10) 165
Time In Exercise Phase 00:13:38
Max. Systolic BP 196 mmHg
Max Diastolic BP 72 mmHg
Max Heart Rate 166 BPM
Max Predicted Heart Rate 152 BPM

The resting blood pressure was 122/70 mmHg.

We stopped the test because they wanted only about 80% effort, not maximum effort, as they didn’t want me breathing too hard for the echocardiogram at the end of the test. They reported the termination condition as “dyspnea (shortness of breath)”, but I was still able to talk fairly comfortably when we stopped, so it definitely wasn’t maximum effort. When I was wearing the Zio monitor, I got up to 176bpm (though that was with an SVT episode—my highest sinus rate was only 160 bpm). Still, 16.5 METS is not too shabby for a 68-year-old man.  If I do another stress test in future, I’ll probably push for a higher level of exertion.

Here are the main observations from the test:

No ischemia with good tolerance and normal LVEF
PVCs, PACs, short runs of SVT


Normal BP response to exercise.
Resting ECG Sinus rhythm @ 56 bpm.
Stress ECG: No ischemic ST changes. Rare PVCs during stress. Rare PACs during exercise and recovery. Short runs of PAT.
Left Ventricle: Normal global systolic function. There are no wall motion abnormalities.
Immediate Post Stress Echocardiogram: There is appropriate exercise augmentation of the ejection fraction. There are no exercise-induced wall-motion abnormalities.

Note: PAT stands for paroxysmal atrial tachycardia—a type of paroxysmal supraventricular tachycardia (PSVT). So we did manage to trigger an SVT episode, but there doesn’t seem to be much more information—everything looks pretty normal. 

I guess in cardiology, having arrhythmias be hard to catch is probably good news, but I don’t know why they were so common when I had the Zio monitor on, but so rare now, just a few months later.

2023 March 27

Yet another monogram stamp

Filed under: Uncategorized — gasstationwithoutpumps @ 20:38
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In Monogram stamps again, I showed some clay stamps I’d 3D-printed with handles.  I was not really happy with the design of the one I did for Liz, though she had approved the design before I printed it.

LIZ (in Apple Chancery font). The separate letters result in some stringing and blobbing as the nozzle moves from one letter to the next. I tried to clean it up with a riffler, but there was only so much I could do.

Today I designed a new monogram for Liz, based on the Cinzel Decorative font, but moving the individual letters in Inkscape to overlap, then converting them to paths and unioning the paths. The resulting design is a little more elegant:

This is the design of the monogram that I sent to Liz for her approval.

And here is the resulting stamp:

The stamp is 18mm wide at the top and 17.5mm high. There is a bit of blobbing on the end of the curl on the I, and a little on the serifs of the L (which look intentional in the final impression). A better quality 3D printer (or even better adjustment of mine) might make a print that doesn’t need cleaning up with a riffler.

Designing the clay stamps is fun, and the printing is fairly fast (about an hour to print a stamp).  The amount of plastic used is miniscule: about 4g or 10¢ worth of PLA filament.

2023 March 23

Trilobe planters

Filed under: Uncategorized — gasstationwithoutpumps @ 18:12
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In Incense holders as glaze tests, I showed my first attempt at a die for a hollow extrusion, and why it failed. Here I’ll introduce my second attempt at a die for the same hollow shape.

I showed this cookie cutter for cutting the shape of the outside of the extrusion out of a slab.

Here are the two parts of die. The inner part is intended to be held by a bolt. The notches in the inner circle of the outer die are intended to hold the ends of the spider that support the bolt. Both dies are tapered so that the clay will be wedged together as the clay passes through.

Here is the inner die mounted on the spider, viewed from the side that would be on the bottom of the extruder.

Here is the die in the extruder. You might notice that the spider is not resting in the notches intended for it. That is because the spider tapers in a bit at the end that sits on the die, and I did not measure it accurately, so the notches were too far from the center. The extruder is not very clean, because the high school students always forget to remove the excess clay when they are done. It also helps to put a rag between the clay and the piston, so that the sides are wiped down as the clay is extruded.

I made 5 small planters out of the trilobe extrusion, with the hollow tube drying overnight before being sliced.  The tube dried very fast and slumped a bit on the board it was drying on, losing the 6-fold symmetry. By the time I was shaping the 5th planter, the tube was getting a bit too dry to work with easily. I think that in future I would try slicing the clay while still fairly wet, and letting it dry to leather hard as vertical tubes, rather than as a horizontal tube.

For the glazing, the bottom of every planter had the stamps painted with black, then the excess wiped off, before any other glazing was done. Two of the pots were dipped (the brown one in temoku gold and the candy-red one in candy red)—the other three were hand-painted with commercial glazes.  All the glazes are cone-6 glazes.

All the pots are about 60mm–65mm across (measuring the highest point when lying the planter on its side).  They have two tubes (a long one for the planter body and a short one for the planter foot) joined by a slab that has a couple of holes punched in it. The slab was fresh-rolled while the tube had dried overnight, so there was some difference in the size—this resulted in a bump rather like a joint in bamboo, so I decided that it was a feature, not a bug. I carved notches in the feet, so that each planter has three separate feet.

The planters did vary in height, depending on the lengths of the tubes.  Here they are from shortest to tallest:

Yellow planter

The yelllow planter is 66mm–69mm high. The glaze is a commercial “China yellow” glaze applied with a brush in two layers. Getting a uniform coat was difficult, and some bubbles formed in the glaze.

The bottom was painted with 1 layer of commercial “marigold” glaze. The black glaze in the stamps is clearly visible.

Brown planter

The brown planter is 68mm–72mm high. The surface was brushed with steel brush before the bisque firing, making a rough surface that held the glaze well. Some of the roughness can still be felt after the glazing.

The brown planter was dipped in temoku gold glaze, using a piece of wire through the hole in the center to hold the pot. This side of the pot came out somewhat lighter and more speckled than the side shown in the previous picture.

The black in the stamped portions is not really visible with the darkness of the temoku gold.

Candy red planter

The candy-red planter (dipped once in candy red glaze) was the one that deviated most from being vertical, with the top varying from 78mm–88mm high. I haven’t decided yet whether this is a problem or a feature. Most of the variation is in the tube that makes up the foot of the planter, but there is some curvature to the top tube also.

This view of the planter on its side shows some of the curvature.

The inside of the pot is fully coated, but the candy-red glaze is nearly clear in places. This seems to be a common problem with this glaze.

The foot shows considerable distortion of the trilobe extrusion, because of the tube getting a little too dry while lying on its side. Again, I’m not sure whether I prefer a more regular “machine-made” extrusion look or this rather funky “handmade by incompetents” look. Perhaps there is some middle ground to look for.

Cherry red planter

The cherry red glaze came out as a really bold red—much better than the almost transparent candy red. The planter is 86mm–89mm talll, but rocks a little on its base.

The inside of the planter is glazed 2cm–3cm down, so that the bare clay will not show (much) when the planter is filled with soil.

The bottom of the cherry-red pot was painted with “cinnamon gloss”, which seems to make a more uniform brown than the temoku gold glaze. (I like the speckling of the temoku gold for this application, but it is nice to know that a more uniform brown is available.)

Mist blue planter

The mist-blue planter varies from 92mm to 97mm tall, but has less lean or curvature that the candy-red one. The glaze flowed terribly on this one, so I will not use it again, even though I like the color.

The bottom right foot here shows where the glaze bubbled and flowed onto the kiln shelf—something you really don’t want to have happen with a glaze!

Looking down from the top, you can see a little cracking between the slab and the sides—it was difficult to apply pressure for the joining that deep into a narrow tube. I think that there is sufficient strength, because the slab and the tubes are well joined on the outer surfaces, but I’ll have to think of a technique for making smoother joins on the inside.

The foot of the mist-blue planter was painted with purple crystal, which seems to result in a rather unpleasant mix of purple and green colors—so this pot has two glazes that I don’t want to use again. You can also see two places on the foot where the outer mist-blue glaze flowed onto the kiln shelf, even though I had left at least 3mm unglazed as specified.

So my first real attempt at using hollow extrusions was not a total disaster, though I clearly have to improve my technique a lot. If I get into the pottery class in the fall, I’ll play with this extruder die some more, as well as practicing throwing.  At least with the extruder my wall thicknesses are a fairly uniform 6mm–7mm, unlike the very thick walls of my thrown pots.

I’ll probably plant some small succulents in these pots, then give them all away.

My second through fourth pots

Filed under: Uncategorized — gasstationwithoutpumps @ 13:46
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In addition to the first pot I threw, I had 3 more thrown pots that were kept through trimming, bisque firing, and glazing.  I also had a number of extrusions: soap dishes, incense holders, and planters (which I’ll post about later).  All my pots are made with Clay Planet’s Bravo Buff clay, as that is what is sold in the class, though several students were using clay purchased elsewhere.  We paid $20 for a bag of clay, which I believe was 25 pounds (11.3kg) of clay, but I didn’t weigh it.

Tiny bowl

The tiny striped bowl is about 96 mm in diameter and 35.5 mm tall. The base is about 60.5mm in diameter. The inside was painted with cobalt carbonate stripes, then had shiny milky white poured in. The outside was dipped in panama blue, then painted with a stripe of black beauty.

The stripes came out well, but the inside of the bowl could have used a little more of the shiny milky white on the bottom. The rim is about 10mm–11mm thick. The bowl weighs 178g and holds about 75ml.

The panama blue is really more a green color, and it should have been dipped twice, as the coverage is a bit patchy. There was not enough of a foot to grip with tongs, so the rim was held with fingers for the dipping. The black band was sloppily drawn (I have trouble holding a brush steady). Where the shiny milky white and the panama blue overlap, there is a good blue color—in future I might want to do one dip of shiny milky white before one dip of panama blue. I also have to be careful to make sure that I get a good coating of glaze everywhere, as the thin spots seem to have opened up to expose bare clay (or with such a thin layer of glaze that it is effectively clear).

Red footed bowl

The red bowl is about 10 cm in diameter and about 63mm tall. It had shiny milky white poured for the inside, and candy red dipped for the outside. A lot of the red disappeared in the firing, producing a transparent glaze in places.

The top rim of the bowl is rather thick (10mm–11mm), and the whole bowl is rather heavy at 295g—especially as it holds only 150ml.

The candy red came out much clearer on the bottom, as there was probably less oxygen there, even though the foot was notched in three places to make 3 separate feet.

Robin’s egg blue bowl

My widest bowl is about 132mm–135mm in diameter and about 46mm –50mm tall. The variation in height is very apparent when the bowl is filled with liquid.
The inside had one pour of shiny milky white (two would have been better) and the outside was dipped in a new glaze for the studio—robin’s egg blue.

The bowl weighs 421g and holds about 225ml. The side are 10mm–14mm thick.

I think that the robin’s egg blue really needs two dips to get adequate coverage.

Although none of these bowls are of a quality that I would buy them, I’m no embarrassed by them as first attempts.  I hope to be able to take the class again in the fall and get a little better at both throwing and glazing.  What I need to work on most is lifting the sides better, so that the I have less-heavy pots—the bowls and mugs I have bought from professional potters are generally 4mm–5mm thick, not 10mm–14mm thick.  I may not be able to control the clay when it is that thin, but I’d like to get down to 7mm anyway.

Last incense holder

Filed under: Uncategorized — gasstationwithoutpumps @ 12:23
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In Incense holders as glaze testsI provided pictures and glaze information on a number of incense holders I had made out of the failed hollow extrusion (using bravo buff clay). One of the holders had not been fired with the rest, as it kept rocking onto the glazed portion and they did not want it sticking to the shelf.  I scraped off the excess glaze and had it fired in the next run of the glaze kiln.

Here is the last of the incense holders. It is about 16cm from end to end and 26–29mm wide. It had two dips of slate blue with dots of shiny milky white painted on.

The bottom has a long unglazed area—some from waxing, some from scraping off excess glaze.

This piece was a little too dry and cracked (prior to the first firing—I might have been able to repair it with slip). There were also flaws in the glazing on both sides, possibly from excessive handling—I should have touched up the top edges after scraping the excess off the bottom.

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