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NNadir

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Gender: Male
Current location: New Jersey
Member since: 2002
Number of posts: 25,196

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Reducing transmission of SARS-CoV-2

This somewhat scary "perspective" is found in the current issue of Science: Reducing transmission of SARS-CoV-2 (Kimberly A. Prather1, Chia C. Wang2,3, Robert T. Schooley4 Science 26 Jun 2020: Vol. 368, Issue 6498, pp. 1422-1424)

I presume it's open sourced:

Some excerpts:

Respiratory infections occur through the transmission of virus-containing droplets (>5 to 10 µm) and aerosols (≤5 µm) exhaled from infected individuals during breathing, speaking, coughing, and sneezing. Traditional respiratory disease control measures are designed to reduce transmission by droplets produced in the sneezes and coughs of infected individuals. However, a large proportion of the spread of coronavirus disease 2019 (COVID-19) appears to be occurring through airborne transmission of aerosols produced by asymptomatic individuals during breathing and speaking (1—3). Aerosols can accumulate, remain infectious in indoor air for hours, and be easily inhaled deep into the lungs. For society to resume, measures designed to reduce aerosol transmission must be implemented, including universal masking and regular, widespread testing to identify and isolate infected asymptomatic individuals.

Humans produce respiratory droplets ranging from 0.1 to 1000 µm. A competition between droplet size, inertia, gravity, and evaporation determines how far emitted droplets and aerosols will travel in air (4, 5)...

...it is possible that submicron virus-containing aerosols are being transferred deep into the alveolar region of the lungs, where immune responses seem to be temporarily bypassed. SARS-CoV-2 has been shown to replicate three times faster than SARS-CoV-1 and thus can rapidly spread to the pharynx, from which it can be shed before the innate immune response becomes activated and produces symptoms (6). By the time symptoms occur, the patient has transmitted the virus without knowing...

...The U.S. Centers for Disease Control and Prevention (CDC) recommendations for social distancing of 6 feet and hand washing to reduce the spread of SARS-CoV-2 are based on studies of respiratory droplets carried out in the 1930s. These studies showed that large, ∼100 µm droplets produced in coughs and sneezes quickly underwent gravitational settling (1). However, when these studies were conducted, the technology did not exist for detecting submicron aerosols...

...Measurements now show that intense coughs and sneezes that propel larger droplets more than 20 feet can also create thousands of aerosols that can travel even further (1). Increasing evidence for SARS-CoV-2 suggests the 6 feet CDC recommendation is likely not enough under many indoor conditions, where aerosols can remain airborne for hours, accumulate over time, and follow airflows over distances further than 6 feet (5, 10)...


The article goes on to suggest an explanation of why Taiwan, despite having no lockdown, had a low infection rate, while the United States didn't.

Hint: Not that we wish to offend members of the Trump cult here at DU, it involves, um, masks. The article suggests that "social distancing" may not be enough.


A graphic:



The caption:

Masks reduce airborne transmission.

Infectious aerosol particles can be released during breathing and speaking by asymptomatic infected individuals. No masking maximizes exposure, whereas universal masking results in the least exposure.


It is important to note, and it's easy to forget this, that wearing a mask does not protect the wearer so much as it protects other people. This explains the Republican resistance to wearing them. They just don't give a shit about other people.

Afforestation falls short as a biodiversity strategy

An opinion piece in this week's issue of the journal Science comments on the proposal to address climate change by planting oodles of trees: Afforestation falls short as a biodiversity strategy
(Susana Gómez-González1,2,*, Raúl Ochoa-Hueso1, Juli G. Pausas3, Science 26 Jun 2020: Vol. 368, Issue 6498, pp. 1439)

I believe it's open sourced.

An excerpt:

The recent EU Biodiversity Strategy for 2030 (1) recognizes the importance of biodiversity for increasing our resilience to natural disasters and pandemics and, thus, for human well-being. Although it proposes ambitious measures such as reversing pollinator decline and controlling invasive species, it also introduces the ill-advised idea of planting 3 billion trees.

Massive tree plantation programs (2, 3) have been strongly criticized by the scientific community for their negative ecological and economic impacts and their limited role in climate change and CO2 mitigation (4–8). The specific number of trees proposed in the EU Strategy suggests a lack of a serious, science-based ecological assessment of actual restoration needs. Meeting such a target could threaten biodiverse treeless ecosystems (4, 6, 7, 9) and would waste an opportunity to implement ecologically sound management practices to restore fully functionally integrated mosaics of natural, seminatural, and sustainable agricultural ecosystems.

Massive tree planting could also substantially change the fire regime, especially given the increasing frequency of heat waves and droughts in an area with high population density (10). The probability of large intense fires that threaten biodiversity and human assets is largely influenced by the type, amount, and continuity of biomass...


I personally believe that biomass can play a constructive role in removing carbon dioxide, if, and only if, it is does so safely in an environmentally sustainable manner. Let's be clear, combusting biomass is neither safe nor sustainable, but there are many things to recommend using the large surface areas that biomass can accommodate in a setting of pyrolysis or steam reformation.

However biodiversity is important, and strategies like making monoculture palm oil plantations out of rain forests to generate "renewable biodiesel" doesn't cut it, nor does destroying the ecosystem of the Mississippi delta to make "renewable corn ethanol," nor does putting service roads through virgin forests to install and haul away wind turbines every twenty years with diesel trucks doesn't cut it.

Possibly the authors are on to something.

COVID-19's unsustainable waste management

A brief commentary appeared in the current issue of Science that is worthy of some attention: COVID-19's unsustainable waste management (Siming You1, Christian Sonne2, Yong Sik Ok3,4,* Science Jun 26, 2020 Vol. 368, Issue 6498, pp. 1438)

It's probably open sourced.

A brief excerpt of the short note:

The coronavirus disease 2019 (COVID-19) pandemic has led to an abrupt collapse of waste management chains. Safely managing medical and domestic waste is crucial to successfully containing the disease (1). Mismanagement can also lead to increased environmental pollution. All countries facing excess waste should evaluate their management systems to incorporate disaster preparedness and resilience.

Wuhan, the COVID-19 epicenter of China, experienced a massive increase of medical waste from between 40 and 50 tons/day before the outbreak to about 247 tons on 1 March (2). Cities such as Manila, Kuala Lumpur, Hanoi, and Bangkok experienced similar increases, producing 154 to 280 tons more medical waste per day than before the pandemic (3)...


Since the United States has mismanaged itself because of the growing popularity of ignorance and denial, our waste profile must be corresponding greater than that of say, Vietnam, the country Bone Spur Donald Trump avoided with the liberal application of his father's money, where apparently the government is smarter than his. (This is not intended as an endorsement of Vietnam's government, only a statement that they manage things better than armchair fascists in the US.)

Whether Covid-19 medical waste is infectious, I cannot say.

Personally, as a person who has spent a lifetime thinking about how to convert "waste" into products - I favor the pyrolysis or high temperature steam reforming of all carbon containing wastes, a practice that would make the issue of infectious medical waste null and void, but apparently, I'm an outlier.

Saying Everything While Saying Nothing: Kamala Harris, FDR, and Abraham Lincoln.

Joe Biden is our nominee; and if there is anything this country needs right now, it is decency, of which Biden is an avatar.

He is a fine statesman, but as everyone knows, an elder statesman, although, in contrast of that spoiled lump of putrescent lard in the White House, Biden shows no signs of senility and is in excellent health and possessed of clear thinking.

Nevertheless, it is certainly statistically possible that his Vice President will succeed him at some point.

It has been the good fortune of our country that two magnificent Presidencies followed disastrous Presidencies, the first of these disasters being the Presidency of James Buchanan - who has been rescued from the mantle of "worst President ever" by Donald Trump. Lincoln succeeded him.

The next was the Laissez-Faire Presidency of Herbert Hoover, who was succeeded by FDR.

If you read about the character and leadership qualities of both Lincoln and FDR, both men were characterized by the distinct and oft used ability to dodge the question as a means of gaining allies while making an understated point.

America has been severely damaged by the most corrupt, ignorant, vindictive, and manifestly childish President ever, and we will need greatness again. It is certainly true of Lincoln, and probably true of FDR as well, that what defined their greatness was the challenges they faced.

I just read this article on Kamala Harris, which points up her skill at not answering the question while making a point:

Kamala Harris’s Very Open Secret by Edward-Issac Dovere in The Atlantic.

This excerpt struck me:

With those who know her, she can be thoughtful, funny, engaging, and pragmatic, with little patience for grand theories of governance. She’s focused on what will make a real difference in people’s lives. But the version of Harris the public knows often comes off scripted and indirect, appearing mostly in sound bites and viral videos. Her instinct to parry rather than expound helps her avoid awkward questions, such as during a segment on The View earlier this month, when Meghan McCain asked her if she was in favor of defunding the police. Instead of answering directly, Harris asked what McCain meant, and McCain eventually admitted that she didn’t know herself. Harris successfully avoided taking a potentially controversial position. But she also reinforced her preexisting reputation for evasiveness: I heard from several high-level Democratic operatives that the exchange reminded them of Harris’s habit of dodging critical questions during her presidential campaign.


Joe Biden could pick a can opener as his running mate and I would crawl on broken glass to vote for him.

This said, this skill of Harris's, should she be called to succeed President Biden speaks well to my sense of history.

I was disinterested in Harris during the campaign; I first supported Senator Warren, switching at some point to Mr. Yang, and buying in to Biden as soon as it was down to him and that "Bernie" guy.

I think Joe Biden is doing an outstanding job, and I think he has the right stuff to heal our country. But should his life end in office, Senator Harris, it seems to me has that magnificent quality that characterized two of our greatest Presidents, Lincoln and FDR.

My father's day gift finally arrived, and I watched it tonight.

Juice: How Electricity Explains The World - Juice

Poverty, women’s rights, climate change — indeed, many of the world’s most pressing challenges — can be explained by answering one question: Can you turn your lights on in the morning?


Pretty powerful stuff.

I don't agree with everything that's said in the movie, but have long recognized many of the basic truths therein.

I recommend the documentary.

Ted Cruz and John Cornyn Don't Understand Don't Understand Why Funds Are Being Pulled From Testing.

GOP Sens. Cornyn and Cruz say they don't understand why federal funds are being pulled from coronavirus testing sites (CNN)

...But several lawmakers from Texas, including Republican Sens. John Cornyn and Ted Cruz, say they do not understand why the federal assistance is being pulled as their state sees more and more coronavirus cases.
"Frankly, I didn't understand what they were thinking," Cornyn told CNN on Thursday...


Are they really that stupid? They don't understand...

People with integrity and decency can understand completely. Two Senators who swore to uphold the United States Constitution spit on their oath and when presented with a vote to remove an obviously insane and corrupt "President" from office, decided that after more than two centuries the rule of law was less important than embracing an uneducated racist con man's cult of personality.

They don't understand?

They're idiots.

Yeah what about that? It's not working!

This one's dedicated to all the people who didn't believe in me...



https://www.freepressjournal.in/viral/fpj-fun-corner-best-whatsapp-memes-and-jokes-to-lighten-your-mood-amid-covid-19-on-june-23-2020

In general, I don't like to make an argument that the only reason people do anything...

...is for money. When confronted with such an argument when it's addressed at me - because of my views on energy - I note that anyone who assumes that is probably doing so because they lack a moral basis sufficient to recognize that some people are motivated to do things because they are the right things to do.

Of course, though one can take one's self assumed holiness too far, and sometimes we get corrupted by it.

There is nothing in Moore's background to suggest that he has either the education or experience to do anything but criticize other people for having failings that he defines from a position of being unassailable. In other words, he is a parasite on failure.

Perhaps at some point he held serious opinions and was seriously concerned about the world, albeit in a wholly inflated way.

However, he makes a lot of money off his holiness, doesn't he? I mean, would he have sold a lot of tickets that smug obscenely disrespectful humor directed at the death of schoolchildren (Bowling for Columbine) in a Gore Presidency?

Would he have made a dime off of Fahrenheit 9/11 if Al Gore rather than George W. Bush had been seated in the White House, an outcome which he actively worked to prevent? Would there have been a World Trade Center disaster on which he could hold forth?

He is an emotional and intellectual parasite of a low order, nothing more than a saboteur. I don't consider him a "leftist" at all, and his hatred of the left derives simply from his love of himself. I have zero respect for him. He's not serious; like Trump, he's nothing more than a pernicious clown.

He is unqualified to judge anyone because he has never built a worthwhile thing in his life and has no practical vision of how to make a better world.

At best, he's Rush Limbaugh of an ersatz "left," unprincipled and self absorbed.



Microfluidic electrochemistry for single-electron transfer redox-neutral reactions.

The paper I'll discuss in this post is this one: Microfluidic electrochemistry for single-electron transfer redox-neutral reactions (Yiming Mo,*, Zhaohong Lu,*, Girish Rughoobur, Prashant Patil, Neil Gershenfeld, Akintunde I. Akinwande, Stephen L. Buchwald,†, Klavs F. Jensen,†, Science 19 Jun 2020: Vol. 368, Issue 6497, pp. 1352-1357.)

In the days of Covid-19, I've taken to reading books cover to cover, something I don't normally do; usually I skip around for the "good parts." The degree to which this is intellectually limiting I cannot say, but these days, with many of my favorite libraries closed, coupled with the fact that I need to read almost as much as I need to eat - and I eat too much - I read full books, cover to cover, since I can't get library books any more and worry about running out of things to read.

The book I'm reading right now is about an elaborate scam run by an arrogant young woman and her (possibly) Svengali type boy friend, the young woman being Elizabeth Holmes and her boyfriend, Ramesh "Sunny" Balwani, and the book being Bad Blood: Secrets and Lies in a Silicon Valley Startup by John Carreyrou, a Wall Street Journal Reporter. The hero and heroine of the book were low level, but well educated, young technical people who entered the company the book describes, Theranos, thrilled with its rhetoric and goals, which they believed involved cutting edge, but were swiftly disillusioned because, well, they were smart and there was no earth shattering technology.

All the writing is somewhat dry, the book fascinates me, because, when I was a kid, I worked for a number of start up biotechs, some better than others - none of them fraudulent, although in some the technology failed to pan out - and I always believed that the tech was going to be "earth shattering" but eventually I figured out that "earth shattering" is supremely difficult.

The Theranos "technology" - there was no actual technology that was in any way new - purported to be able to run hundreds of clinical tests using a single drop of blood. Anyone who understands anything about bioanalysis - the disipline that over arches "clinical chemistry" 0 should have known that running hundreds of tests on a pin-prick of blood was patently absurd, but the "hook" for the scam did involve a claim appealing to the very real concept of microfluidics. Modern microfluidic devices are a feature of technology, and they are utilized in bioanalysis, for example in nanospray mass spectrometers, and recently a company did introduce a technology - a real technology - that is capable of using nanoliter droplets to access complex chemistries in biologic fluids without the void volumes associated with any kind of fluidics. (I have not studied this device in any detail, and a concern is the loss of orthogonal separations represented by chromatography, but the device is very real, and has been beta tested at major pharmaceutical companies.)

If one reads Bad Blood and actually possess a modicum of knowledge, one can see that Theranos did go through the scientific motions, and did hire real scientists, but compartmentalized them away from one another, but eventually they all caught on to the fraud and after attempting to address their concerns through channels, resigned in disgust. (One, tragically, a talented scientist named Ian Gibbons, actually committed suicide.)

But no, Theranos did not have microfluidic magic behind their putative device. They had nothing but the involvement of high level political and military figures on both the right and the left, George Schultz, Henry Kissinger, James Mattis, Bill Frist on the right, David Boies, William Perry on the center left; Elizabeth Holmes, the Theranos CEO, the arrogant young woman mentioned above gave fund raisers for Hillary Clinton, was praised by Bill Clinton in a public forum, and received written praise from Barack Obama. (Rupert Murdoch was an investor to the tune of $125,000,000 and to his credit - who knew he could do anything ethical - he did not quash the Wall Street Journal articles authored by Carreyrou that made his investment in Theranos worthless.)

Anyone can be credulous, even major political figures. (It is telling that there were no scientists on the Theranos board; her board was comprised entirely of major political and military figures, none of whom knew anything about science other than the fact that they claimed vaguely to like it.)

Enough drivel...about the paper.

The paper is about microfluidic devices that can perform tasks that are simply not possible on a larger scale. Since they are flow devices, they are amenable to continuous processes. As I recently discussed with a correspondent in another series of posts in this space, continuous processes are generally more economic and cleaner than batch processes.

From the paper's introduction:

Over the past decade, pioneering developments of visible-light photocatalysis in organic synthesis have enabled previously inaccessible redox-neutral reactions that proceed through single-electron transfer (SET) processes (1, 2). Nonetheless, the use of photocatalysts, mostly precious metal complexes (3) or sophisticated organic dyes (4), could have practical limitations, such as the nontrivial tuning of redox potentials; high cost of transition-metal photocatalysts at scale (5); incompatibility of photocatalysts with strong nucleophiles, electrophiles, or radical intermediates (6, 7); and challenging removal of transition metals during purification of the products (8, 9). Electrosynthesis, on the other hand, is an emerging redox platform accessing environmentally benign, cost-effective, scalable, and distinctive transformations (10) powered by inexpensive electricity. Consequently, we considered whether electrochemistry could be applied in a practical photocatalyst-free system for SET redox-neutral reactions.

Most of the reported synthetic electrochemistry relies on reactions on a single electrode with by-products generated on the other electrode, and, as such, the nature of the desired electrochemical transformations is either oxidative or reductive (10). In contrast, redox-neutral electrochemistry (i.e., paired or coupled electrosynthesis), which involves two desirable half-electrode reactions performed simultaneously, is underdeveloped, despite its relative material and energy efficiency (10–12), and examples of radical-based redox-neutral electrosynthesis are even rarer (13–15). In conventional paired electrochemistry setups, the difficulties associated with matching the generation and interelectrode transport rates of the different highly reactive intermediates pose substantial obstacles to achieving the selective transformation over alternative undesired pathways. Microfluidics, however, has been shown to offer controllable and rapid species transport within a micrometer channel (16), with recent applications in electrosynthesis for improved reaction performance (17, 18). To further exploit the capability of microfluidic electrochemistry, we sought to develop a microfluidic redox-neutral electrochemical (μRN-eChem) platform to overcome the challenges of photochemistry-inspired SET redox-neutral reactions that involve reactive intermediates generated from both electrodes.


The authors chose to explore a radical based chemical reaction, Kolbe Electrolysis, which generally gives a mixture of symmetric and asymmetric couplings when two carboxylic acids are the starting material, making it somewhat useless for industrial chemistry, at least industrial chemistry designed to make pure compounds. (The related Kolbe Reaction, by contrast, is one of the first large scale chemical reactions to be utilized in chemistry. It is utilized to make salicyclic acid from phenol, salicyclic acid being the precursor to the wonder drug aspirin.)

A figure from the paper shows some examples:



The caption:

Fig. 1 Background and microfluidic redox-neutral electrochemistry (μRN-eChem).

(A) Comparison of photochemistry and electrochemistry for SET redox-neutral reactions. PC, photocatalyst; PCRed, ground-state PC; PC*Red, excited-state PC; PCOx, oxidized-state PC. (B) Concept of μRN-eChem for the cross-coupling reaction of persistent and transient radicals. (C) Mechanism of redox-neutral electrochemical cross-coupling reaction of carboxylic acids and electron-deficient aryl nitriles. R–COOH, carboxylic acid (where R is the alkyl group); R•, alkyl radical; EWG, electron-withdrawing group. (D) UV-Vis spectroelectrochemical lifetime measurement of BPDN radical anion. a.u., arbitrary units; Decomp., decomposition; [C], concentration; λ, wavelength. (E) Effect of interelectrode distance on reaction yield. Two batch setups were tested (fig. S5), and the setup with higher yield is presented in this plot. Me, methyl.


SET = Single Electron Transfer

The procedure for making the microflow device is briefly discussed in the paper:

We engineered a μRN-eChem flow cell with a variable interelectrode distance (25 to 500 μm). Two GC plate electrodes, micromachined by a 532-nm laser, sandwich a thin fluorinated ethylene propylene film to create the microfluidic channel (see fig. S1)


More detail is given in the supplementary data:

Glassy carbon electrodes (50 mm × 50 mm × 3 mm) were purchased from Alfa Aesar (P.N. 42820-FI) without further treatment. (Note: only type 1 glassy carbon electrode works for chemistry developed in this work, and type 2 glassy carbon electrode shows unstable electrode surface properties under our electrochemical conditions.) Fluorinated ethylene propylene (FEP) spacers with various thickness (0.001” – 0.005”) were obtained from CS Hyde Company. PTFE and PFA films were also tested for flow cell sealing. However, FEP film proved to be the best for sealing the thin gap between glassy carbon electrodes (no leakage tested up to 40 psig of nitrogen gas).

Fabricating a small diameter and high aspect ratio deep hole in glassy carbon is challenging using the traditional milling process. Here, we used the laser micromachining process to microfabricate these fluid paths. In this process, the laser was used to oxidize the glassy carbon into carbon dioxide in the presence of atmospheric oxygen. The resulted carbon dioxide gas escaped to the environment, giving the efficient removal of glassy carbon. Deep holes were obtained by gradually moving the focus of the laser beam and removing the material layer-by-layer until the desired depth was achieved. A laser micromachining system from Oxford Lasers was used for drilling the holes. The laser source in the system was a Q-switched frequency-doubled Nd:YAG diode-pumped solid-state pulsed laser with a wavelength of 532 nm and a pulse duration of 20 ns. The laser was focused using a 100 mm focal length lens giving a spot size of 10 micrometers. For drilling holes, the average laser power of 1.4 W was used.


Generally, supplementary data is open sourced even when the full paper isn't. Interested parties can open it to see nice photographs of the apparatus and all kinds of cool experimental details.

Some reaction substrates:



The caption:

Fig. 2 Substrate scope of decarboxylative arylation in continuous-flow synthesis enabled by μRN-eChem.
See the supplementary materials for detailed reaction conditions for each substrate; reactions were performed on a 0.4-mmol scale, unless otherwise noted. Asterisks indicate isomers observed, and in all cases the major isomer is depicted. Yields refer to the combined yield of all isomers. Boc, tert-butyloxycarbonyl; t-Bu, tert-butyl; Et, ethyl; rr, regioisomeric ratio.


The general scope of the reaction:



The caption:

Fig. 3 General applicability of μRN-eChem platform for SET redox-neutral chemistry.

(A) α-Amino C–H arylation. (B) Deboronative arylation. (C) Thiol-catalyzed allylic C–H arylation. HAT, hydrogen atom transfer; i-Pr, isopropyl. (D) Minisci-type radical addition to heteroarenes. Mediators (Med) used are ferrocene or 4-methoxytriphenylamine. Ts, tosyl; DMSO, dimethyl sulfoxide; NHP, phthalimide. (E) Ni-catalyzed C–O cross-coupling. dtbbpy, 4,4′-di-tert-butyl-2,2′-dipyridyl. Asterisks indicate high-performance liquid chromatography yield obtained from batch setup (fig. S5B) under identical electrochemistry conditions. See the supplementary materials for detailed reaction conditions.


Whether this approach is industrially viable will depend on the value and volume of the products formed. I have been involved with projects where the required world supply of highly potent antineoplastic drugs was roughly 5 to 10 kg, enough to treat many thousands of patients, all the patients in the world who needed the drug.

A high value product's synthesis is shown using the technology:



The caption:

Fig. 4 A fully electrochemical two-step synthesis of liquid crystal material 5CB.

See the supplementary materials for detailed reaction conditions. DMF, N,N′-dimethylformamide; PP, polypropylene.


The economic and environmental benefits of this technology will depend on solid phase printing of the device - which certainly seems possible - device life time and reliability and a number of other factors, but it is likely to have at least niche application, perhaps even broad application.

As I say about many of my posts, it's esoteric but hopefully interesting.

For those involved in being a father or celebrating a father, may you have the happiest of Father's days. Mine was perfect because I could wake up not only with love for my sons, but wake up to the news the fine young people who engineered the wonderful comedic humiliation of the Grand Orange Ignorant Racist. Love and kisses to those K-POP people, whoever and whatever K-POP people are. Bless you all.

This coming generation will be a great generation.
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