I've got two Minolta 35mm film SLR cameras, (an old 7-series, and a much newer Maxxum 4). They're not professional-grade cameras by any means, but I like them far more than any digital camera I can afford to buy. Minolta dropping out of the camera business entirely probably means that finding accessories for them is going to suddenly become difficult.
How so? I'm an avid film user (not because of digital hatred, just 'because') and agree that it's sad KM is getting out of the business, but the used market is flooded with SLRs, flashes and lenses for the Minolta line. Same goes for the other major brands. Camera fairs in my area (Toronto, Canada) are always saturated with used 35mm SLR equipment selling for a fraction of their original price.
Between eBay and on-line classifieds, you'll be set for accessories for a while. In a way, the rapid move to digital is a blessing for those still using 35mm. It gives the rest of us the chance to buy used lenses and other accessories that were previously out of reach ($-wise) to the amateur.
The problem with Foxit is in printing. It's slow. REALLY slow. It's as if it sends all the text as bitmaps or something. A simple.PDF journal article from Acrobat 7 that shows up in the Windows print queue as a 3 or 4 MB file easily balloons to 60-70 MB from Foxit.
I appreciated the fast loading time but the printing issue killed Foxit for me.
There weren't too many hacks at MIT when I was there as a grad student. Sure, they dressed up the Building 10 dome as R2D2 when Star Wars Episode 1 came out, but that was about it...
...except for what happened at a parents visiting weekend one year. The administration had hung a giant banner reading "Welcome MIT Parents" across the atrium of Lobby 7 (the main entrance to MIT). Simple hack: within a day or two it had been changed to "Welcome MIT Debtors", and it hung that way for the rest of the weekend.
Concepts in group theory are actually used quite a bit in chemistry. Molecules can be assigned to groups based on their symmetry properties, and these groups can be used to predict the molecules' spectroscopic properties. This is extremely handy in inorganic chemistry when you want to determine (for example) how many different infrared absorptions a metal complex should have.
The lingo of group theory has firmly entered chemistry as well. Even organic chemists will routinely talk about molecules with a C2 axis, systems with D3h symmetry, etc.
The book to read on this topic is "Symmetry and Spectroscopy" by Harris and Bertolucci. It's published by Dover, so it's cheap.
You can through around definitions all you want, but most scientists working in the field would agree that your definition of nanotechnology is exceedingly narrow.
The common thread in what gets described as "nanotechnology" is bottom-up assembly: nanoscale objects are assembled by exploiting specific intermolecular forces (as opposed to whittling away a block of metal).
In Rubner's application the coating is composed of alternating layers of positively charged polymer (polyallylamine) and negatively charged silica nanoparticles. Self-assembly occurs by alternating polyelectrolyte deposition (otherwise known as layer-by-layer assembly, LbL) and the individual layer thicknesses are nanometer-scaled.
Rubner is a leader in this field. It certainly qualifies as nanotechnology.
Congrats. How large are the nanoparticles? Do you make them in-house or buy them? I assume they are assembled using an LbL technique?
jhw3
Swager group alumnus
On the other hand, photographers at a football (soccer) match- in the UK at least- have favoured digital (to the best of my knowledge) for quite a few years now; even though until recently, it was far more expensive and lower in quality than the equivalent film cameras. Why?
An additional reason (besides the turn-around one you gave) is that the small sensor of digital SLRs effectively "multiplies" the focal length of lenses, providing "instant access" to the long focal lengths sports photographers so often use. Wildlife photographers love digital for similar reasons.
No chemists really think that the lanthanides and actinides are "footnotes" in the periodic table. In truth both rows should be inserted under Group 3. We just put them under the table because the first option would make the table too wide.
Hydrogen is difficult to place in a group because it's basically a single proton with a single electron whizzing around it. In fact, in organic chemistry we usually just refer to hydrogen ions as "protons" -- which they are. The element itself has some properties of halogens and some properties of alkali metals, which is why it sometimes gets put in "both" groups.
Practising chemists usually know where the elements they work with lie in the periodic table. Outside of school use, the main use for periodic tables is to quickly find atomic weights (sometimes also electronic configurations or physical properties). Annotated variants of the "old version" are great for this. If this data can't be found quickly, the periodic table is useless.
I'm a chemist too but my perspective on the ACS is very different. These are the guys who publish many of the top journals in the field (available for very reasonable subscription rates -- compare with Elsevier and other private publishers), curate and maintain the CAS database, organize twice-yearly annual meetings that bring together tens of thousands of chemists (and include massive job fairs), not to mention the dozens of local sections that are great for career networking, and and put out a useful weekly newsmagazine that covers chemical news from the academic and industrial worlds. What do you want from the ACS that they haven't given you?
It's incredible to see the/. crowd jump all over the ACS. They aren't some evil Microsoft-like corporate entity. They are a >100-year-old professional society that has continually served chemistry in journal. Long after most of the chemical societies in Europe (with the exception of the Royal Society of Chemistry and the German Chemical Society) have become irrelevant, the ACS still serves chemists.
In addition to Ilford, who do make nice papers, there are also a number of Eastern European manufacturers (Forte, Efke, etc) who have come on the scene in the last few years. Their films and papers are in some ways a throwback to the technology of the 50s and 60s and they have a big following. Endless discussions about this stuff at the Analog Photography Users Group http://www.apug.org/.
I'm sure the popularity of these new papers hasn't helped Kodak. I gave up on Kodak a while ago due to their constant re-shuffling/re-branding of the product line. As long as HC-110 is still available I'll be happy.
I'm a chemist and just had a quick read through the paper (published in this week's Cancer Research). I'm already a little familiar with this work from having seen James Baker (the principal investigator) speak about it a few years ago.
The concept behind what he is doing is not altogether new. It is basically an example of targeted drug delivery -- an encapsulated drug payload (in this case methotrexate, a chemotherapeutic) is directed toward a cancer cell by means of another molecule that specifically recognizes the cancer cell. Antibodies are often used for the actual targeting -- but they are large proteins, harder to work with due to their size and chemical fragility. Folate is much easier to manipulate chemically and cancer cells like it, so this is a win-win.
The carrier they are using is a PAMAM dendrimer. There is a short article on dendrimers on Wikipedia here: http://en.wikipedia.org/wiki/Dendrimer In the Wikipedia article, the growing dendrimer they illustrate in Figure 2 is a PAMAM dendrimer. In this case they're using them as a source of a whole bunch of amine groups in one molecule. they use these amines to attach folate, methotrexate, and various fluorescent dyes (for tracking purposes) via the same chemical reaction -- amide formation at the end of the dendrimer branches.
On their own, each of these applications (carrying the dye, carrying the chemotherapeutic, etc.) is not too exotic and has been done before. The combination can be powerful, though. There is also evidence that having many folates right near each other in space (in this case they are attached to adjacent "branches" of the dendrimer) may make absorption of the dendrimer more efficient through receptor clustering.
Answering the parent's questions:
Is this a biodegradable polymer? Judging from the structure, I would say no. I'm sure people have studied the environmental "lifetime" of PAMAM dendrimers but I don't know the details. It will certainly not degrade quickly in the body, though.
How hard is it to attach molecules to these tree-like structures? If these polymer dendrimer are exposed to various other molecules will some bond naturally, or do they have to be tailored to a specific molecule? It isn't hard to do the attachment in the lab, but specific chemical conditions are required. It doesn't "spontaneously" happen by mixing the dendrimer with anything you might find floating around in a river or lake.
Does that mean that in potential future patients, any free/unabsorbed nanoparticles will be excreted into the public sewage systems, and being (I assume) unfilterable, thereby enter the earths water cycle? Yes, just like all the hundreds of kilos of un-metabolized antibiotics that enter into the world's water supply every year (through urine), breeding resistant bacteria, etc. Dendrimers don't pose any special danger that we aren't already dealing with. They're just polymers with unusual molecular structures. We already dump a lot of water-soluble polymers into the water supply every year (ever taken a shower after having earlier put sunscreen or skin cream on?)
So when you put those together, will these nanoparticles be able to float freely in our oceans and rivers, their dendrimers bonding with molecules found in nature, and then if conditions are right potentially take those molecules inside our cell walls?
I hope I've convinced you that this scenario is not one to be concerned about. It's dangerous and misleading to jump to conclusions like this without understanding the chemistry and biology behind the technology.
I agree that on the whole Jews did better under the Arabs than under the Christians in Spain. But there were some very sour moments even under Arab rule. A good book to read on this is "End of Days" by Erna Paris.
Jews were leaving Spain well before the 1492 expulsion. Many of the great Sephardic scholars, Maimonides and Nachmanides in particular, were basically forced out of Spain due to religious persecution by either Arabs or Christians.
in modern usage, ashkenazis come from europe. Sephardic jews come from the near/middle east.
the definitions are a little different though. Ashkenazis are, by definitions, supposed to be jews whos family came from germany or eastern europe. sephardics, oddly enough, are supposed to be descended from families from spain or portugal.
Not so odd. Sepharad is an old Hebrew name for Spain. Ashkenaz is an old Hebrew word referring to Germany and northern France. The origins of the Sephardim are not in doubt -- many of them have Spanish or Arabic-sounding names (Spain was under partial Arab control up to the 15th century) and speak Ladino, a variant of 15th-century Spanish, even after hundreds of years in exile from Spain (much as the Ashkenazim spoke Yiddish even when relatively few of them lived in Germany).
What about "signing" the Atzei Hayyim?
For those of you who are wondering what I'm talking about, the scroll of a Sefer Torah is wound on two wooden staves, about 18"-24" tall. These are known as the "Trees of Life" (Atzei Hayyim in Hebrew). As the Torah is read from, the reader "spools" the parchment from one of them to the other to go forward (or back if need be) in the scroll.
The parchment is, IIRC (haven't read from the beginning of Genesis or end of Deutoronomy in a scroll for a while) tied on to the Atzei Hayyim. What about marking, perforating, or otherwise "signing" parts of the Atzei Hayyim? It is very laborious to detach and re-attach the scroll, making it discouraging to "swap" them, and the "signature" on the Atzei Hayyim could be in an obscure place. I'd think this would be a better (and less halachically problematic) solution.
I'm with David. As long as the text is clear and undamaged everything is kosher IIRC. It's hard to keep a Sefer Torah free of tears. I'm not surprised that the Parshat Pinchas in your synagogue's Sefer Torah is torn. Considering how many times a year it is read from (several dozen I'd think) plus rolling damage etc.
Many people here seem to be slagging Pascal, but to me (as a non-programmer) it has always seemed to be the perfect mix of simplicity and power. I taught myself Pascal from an encyclopedia entry on it (!) All undergraduate Chemistry majors at my university (in the mid-90s) were required to learn at least basic Turbo Pascal as part of the curriculum. One of our key analytical chemistry assignments was to program an interface to a spectrophotometer through a A/D converter.
The programmers among you may laugh, but it would have likely taken the entire semester to learn to do this in some variant of C, and I doubt BASIC would have been up to the job. Pascal fit the bill perfectly for this task. I still use it (very) occasionally when I need a quick programming solution.
I lived in Cambridge MA until this past spring and was a Zipcar member for about two years. The system is streamlined and works incredibly smoothly. Any problems I had with car bookings were my own fault (i.e. booking a car for 11 p.m. instead of 11 a.m.). It works so well with the Web that it is impossible to imagine something like Zipcar being workable before the Internet age.
For a long time, Zipcar tried to foster a sense of community in which abusing the cars (leaving garbage, empty fuel tanks, smoking, etc.) was highly discouraged. It would happen occasionally, but it was rare. They had somehow avoided the "tragedy of the commons".
Zipcar really fills a niche. It's not meant to be a bus replacement service, but is incredibly convenient for groceries and (especially) evening outings to MBTA-inaccessible suburbs. It was also really handy for times when you needed a van or station wagon. Overall we got by car-free in Boston with the help of Zipcar and public transit for everyday commuting (Zipcar isn't meant for commuting and those who use it for that purpose end up paying a lot).
When I left Boston Zipcar seemed to be moving in more of a "fancy lifestyle" direction, stocking their fleet with Mini Coopers and other snazzy but not necessarily cost-efficient cars for those who wanted to impress. I hope this move doesn't destroy the hippie public spirit of Zipcar.
It's interesting to see people here ganging up on the ACS. Among academic and industrial chemists they aren't seen as some kind of evil organization. Their main activities are publishing journals, organizing meetings, and maintaining things like the Chemical Abstracts database that SciFinder searches. Their journals are high-quality and very reasonably priced compared to for-profit scientific publishers like Elsevier.
SciFinder's main value lies in chemical structure searching. Complex molecules are way easier to draw than to name, and though SciFinder may have a clumsy UI, I can use it to draw an arbitrary organic structure, complete with wildcards, and have it search the literature (including patents) as far back as the 1880s for references to it. Google Scholar has nothing close to this capability.
It's great that Google is implementing this kind of free search function but no-one should get the idea that Google Scholar is in any way a SciFinder killer (yet).
Slashdot Mirror
Between eBay and on-line classifieds, you'll be set for accessories for a while. In a way, the rapid move to digital is a blessing for those still using 35mm. It gives the rest of us the chance to buy used lenses and other accessories that were previously out of reach ($-wise) to the amateur.
The problem with Foxit is in printing. It's slow. REALLY slow. It's as if it sends all the text as bitmaps or something. A simple .PDF journal article from Acrobat 7 that shows up in the Windows print queue as a 3 or 4 MB file easily balloons to 60-70 MB from Foxit.
I appreciated the fast loading time but the printing issue killed Foxit for me.
Concepts in group theory are actually used quite a bit in chemistry. Molecules can be assigned to groups based on their symmetry properties, and these groups can be used to predict the molecules' spectroscopic properties. This is extremely handy in inorganic chemistry when you want to determine (for example) how many different infrared absorptions a metal complex should have.
The lingo of group theory has firmly entered chemistry as well. Even organic chemists will routinely talk about molecules with a C2 axis, systems with D3h symmetry, etc.
The book to read on this topic is "Symmetry and Spectroscopy" by Harris and Bertolucci. It's published by Dover, so it's cheap.
You can through around definitions all you want, but most scientists working in the field would agree that your definition of nanotechnology is exceedingly narrow. The common thread in what gets described as "nanotechnology" is bottom-up assembly: nanoscale objects are assembled by exploiting specific intermolecular forces (as opposed to whittling away a block of metal). In Rubner's application the coating is composed of alternating layers of positively charged polymer (polyallylamine) and negatively charged silica nanoparticles. Self-assembly occurs by alternating polyelectrolyte deposition (otherwise known as layer-by-layer assembly, LbL) and the individual layer thicknesses are nanometer-scaled. Rubner is a leader in this field. It certainly qualifies as nanotechnology.
Congrats. How large are the nanoparticles? Do you make them in-house or buy them? I assume they are assembled using an LbL technique? jhw3 Swager group alumnus
An additional reason (besides the turn-around one you gave) is that the small sensor of digital SLRs effectively "multiplies" the focal length of lenses, providing "instant access" to the long focal lengths sports photographers so often use. Wildlife photographers love digital for similar reasons.
... this guy, who summarizes life as a scientist (well, a young scientist) pretty darn well.
I never claimed that we call hydrogen "protons". I said that we refer to hydrogen ions as protons.
No chemists really think that the lanthanides and actinides are "footnotes" in the periodic table. In truth both rows should be inserted under Group 3. We just put them under the table because the first option would make the table too wide.
Hydrogen is difficult to place in a group because it's basically a single proton with a single electron whizzing around it. In fact, in organic chemistry we usually just refer to hydrogen ions as "protons" -- which they are. The element itself has some properties of halogens and some properties of alkali metals, which is why it sometimes gets put in "both" groups.
Practising chemists usually know where the elements they work with lie in the periodic table. Outside of school use, the main use for periodic tables is to quickly find atomic weights (sometimes also electronic configurations or physical properties). Annotated variants of the "old version" are great for this. If this data can't be found quickly, the periodic table is useless.
It's incredible to see the /. crowd jump all over the ACS. They aren't some evil Microsoft-like corporate entity. They are a >100-year-old professional society that has continually served chemistry in journal. Long after most of the chemical societies in Europe (with the exception of the Royal Society of Chemistry and the German Chemical Society) have become irrelevant, the ACS still serves chemists.
I'm sure the popularity of these new papers hasn't helped Kodak. I gave up on Kodak a while ago due to their constant re-shuffling/re-branding of the product line. As long as HC-110 is still available I'll be happy.
The concept behind what he is doing is not altogether new. It is basically an example of targeted drug delivery -- an encapsulated drug payload (in this case methotrexate, a chemotherapeutic) is directed toward a cancer cell by means of another molecule that specifically recognizes the cancer cell. Antibodies are often used for the actual targeting -- but they are large proteins, harder to work with due to their size and chemical fragility. Folate is much easier to manipulate chemically and cancer cells like it, so this is a win-win.
The carrier they are using is a PAMAM dendrimer. There is a short article on dendrimers on Wikipedia here: http://en.wikipedia.org/wiki/Dendrimer In the Wikipedia article, the growing dendrimer they illustrate in Figure 2 is a PAMAM dendrimer. In this case they're using them as a source of a whole bunch of amine groups in one molecule. they use these amines to attach folate, methotrexate, and various fluorescent dyes (for tracking purposes) via the same chemical reaction -- amide formation at the end of the dendrimer branches.
On their own, each of these applications (carrying the dye, carrying the chemotherapeutic, etc.) is not too exotic and has been done before. The combination can be powerful, though. There is also evidence that having many folates right near each other in space (in this case they are attached to adjacent "branches" of the dendrimer) may make absorption of the dendrimer more efficient through receptor clustering.
Answering the parent's questions:
Is this a biodegradable polymer?
Judging from the structure, I would say no. I'm sure people have studied the environmental "lifetime" of PAMAM dendrimers but I don't know the details. It will certainly not degrade quickly in the body, though.
How hard is it to attach molecules to these tree-like structures? If these polymer dendrimer are exposed to various other molecules will some bond naturally, or do they have to be tailored to a specific molecule?
It isn't hard to do the attachment in the lab, but specific chemical conditions are required. It doesn't "spontaneously" happen by mixing the dendrimer with anything you might find floating around in a river or lake.
Does that mean that in potential future patients, any free/unabsorbed nanoparticles will be excreted into the public sewage systems, and being (I assume) unfilterable, thereby enter the earths water cycle?
Yes, just like all the hundreds of kilos of un-metabolized antibiotics that enter into the world's water supply every year (through urine), breeding resistant bacteria, etc. Dendrimers don't pose any special danger that we aren't already dealing with. They're just polymers with unusual molecular structures. We already dump a lot of water-soluble polymers into the water supply every year (ever taken a shower after having earlier put sunscreen or skin cream on?)
So when you put those together, will these nanoparticles be able to float freely in our oceans and rivers, their dendrimers bonding with molecules found in nature, and then if conditions are right potentially take those molecules inside our cell walls?
I hope I've convinced you that this scenario is not one to be concerned about. It's dangerous and misleading to jump to conclusions like this without understanding the chemistry and biology behind the technology.
I agree that on the whole Jews did better under the Arabs than under the Christians in Spain. But there were some very sour moments even under Arab rule. A good book to read on this is "End of Days" by Erna Paris.
Jews were leaving Spain well before the 1492 expulsion. Many of the great Sephardic scholars, Maimonides and Nachmanides in particular, were basically forced out of Spain due to religious persecution by either Arabs or Christians.
the definitions are a little different though. Ashkenazis are, by definitions, supposed to be jews whos family came from germany or eastern europe. sephardics, oddly enough, are supposed to be descended from families from spain or portugal.
Not so odd. Sepharad is an old Hebrew name for Spain. Ashkenaz is an old Hebrew word referring to Germany and northern France. The origins of the Sephardim are not in doubt -- many of them have Spanish or Arabic-sounding names (Spain was under partial Arab control up to the 15th century) and speak Ladino, a variant of 15th-century Spanish, even after hundreds of years in exile from Spain (much as the Ashkenazim spoke Yiddish even when relatively few of them lived in Germany).
What about "signing" the Atzei Hayyim? For those of you who are wondering what I'm talking about, the scroll of a Sefer Torah is wound on two wooden staves, about 18"-24" tall. These are known as the "Trees of Life" (Atzei Hayyim in Hebrew). As the Torah is read from, the reader "spools" the parchment from one of them to the other to go forward (or back if need be) in the scroll. The parchment is, IIRC (haven't read from the beginning of Genesis or end of Deutoronomy in a scroll for a while) tied on to the Atzei Hayyim. What about marking, perforating, or otherwise "signing" parts of the Atzei Hayyim? It is very laborious to detach and re-attach the scroll, making it discouraging to "swap" them, and the "signature" on the Atzei Hayyim could be in an obscure place. I'd think this would be a better (and less halachically problematic) solution.
I'm with David. As long as the text is clear and undamaged everything is kosher IIRC. It's hard to keep a Sefer Torah free of tears. I'm not surprised that the Parshat Pinchas in your synagogue's Sefer Torah is torn. Considering how many times a year it is read from (several dozen I'd think) plus rolling damage etc.
Many people here seem to be slagging Pascal, but to me (as a non-programmer) it has always seemed to be the perfect mix of simplicity and power. I taught myself Pascal from an encyclopedia entry on it (!) All undergraduate Chemistry majors at my university (in the mid-90s) were required to learn at least basic Turbo Pascal as part of the curriculum. One of our key analytical chemistry assignments was to program an interface to a spectrophotometer through a A/D converter. The programmers among you may laugh, but it would have likely taken the entire semester to learn to do this in some variant of C, and I doubt BASIC would have been up to the job. Pascal fit the bill perfectly for this task. I still use it (very) occasionally when I need a quick programming solution.
I lived in Cambridge MA until this past spring and was a Zipcar member for about two years. The system is streamlined and works incredibly smoothly. Any problems I had with car bookings were my own fault (i.e. booking a car for 11 p.m. instead of 11 a.m.). It works so well with the Web that it is impossible to imagine something like Zipcar being workable before the Internet age.
For a long time, Zipcar tried to foster a sense of community in which abusing the cars (leaving garbage, empty fuel tanks, smoking, etc.) was highly discouraged. It would happen occasionally, but it was rare. They had somehow avoided the "tragedy of the commons".
Zipcar really fills a niche. It's not meant to be a bus replacement service, but is incredibly convenient for groceries and (especially) evening outings to MBTA-inaccessible suburbs. It was also really handy for times when you needed a van or station wagon. Overall we got by car-free in Boston with the help of Zipcar and public transit for everyday commuting (Zipcar isn't meant for commuting and those who use it for that purpose end up paying a lot).
When I left Boston Zipcar seemed to be moving in more of a "fancy lifestyle" direction, stocking their fleet with Mini Coopers and other snazzy but not necessarily cost-efficient cars for those who wanted to impress. I hope this move doesn't destroy the hippie public spirit of Zipcar.
Organic chemist and long-time /. lurker here.
It's interesting to see people here ganging up on the ACS. Among academic and industrial chemists they aren't seen as some kind of evil organization. Their main activities are publishing journals, organizing meetings, and maintaining things like the Chemical Abstracts database that SciFinder searches. Their journals are high-quality and very reasonably priced compared to for-profit scientific publishers like Elsevier.
SciFinder's main value lies in chemical structure searching. Complex molecules are way easier to draw than to name, and though SciFinder may have a clumsy UI, I can use it to draw an arbitrary organic structure, complete with wildcards, and have it search the literature (including patents) as far back as the 1880s for references to it. Google Scholar has nothing close to this capability.
It's great that Google is implementing this kind of free search function but no-one should get the idea that Google Scholar is in any way a SciFinder killer (yet).
Just my $0.02.