Friday, April 11, 2025
Babes in the Digital Woods
Sunday, June 5, 2022
Cosmetic Dentistry : The Mayan Style
| Mayan area Courtesy Simon Burchell, wikipedia |
| Artistic representation of the Mayan bejewelled teeth in National Museum of Mexico |
Among the artefacts preserved in the Mexico city National Museum, are skulls dating back to AD 700. In many of these skulls, labial teeth are adorned with inlays of gold or embedded with precious stones. These adornments could have aesthetic/magical /religious connotations. That apart, scientists are amazed at the exquisite craftsmanship. It is indeed astounding how shallow cavities are carved out on tooth surfaces neatly and skilfully using primitive tools. Obviously the craftsmen had an excellent knowledge of dental anatomy.
| Courtesy: Reference 1 |
Sunday, March 6, 2022
Of Pests and Pest Management
| PCN cysts ( in yellow ) clinging to potato roots: Courtesy: wikipedia |
Solanoeclepin A initiates a series of activities both on the outside and inside of the PCN cyst. First, solanoeclepin A induces the cyst wall to become a bit leaky. This causes trehalose syrup to ooze out and water/moisture to rush in, thus irrigating the eggs and facilitating their hatching. However as a part of survival strategy, all of the eggs are not hatched in one go. Professor Benjamin Mimee and his team point out that this could be to increase population persistence throughout growing seasons and to lower competition between hatched juveniles.
Though pesticides are effective, poorer nations find it unaffordable. This where the efforts of a global team of scientists with Professors Danny Coyne, Charles Opperman and Baldwyn Torto at the helm prove valuable. Collectively they have hit upon a simple strategy: wrap the potatoes in banana paper and then plant. The banana paper absorbs most of the exudates, including solanoclepin A, thus preventing hatching signals reaching the PCN cyst. One of the rare instances of humans vetoing Nature in very simple terms.
REFERENCES:
3. Wrap-and-plant technology to manage sustainably potato cyst nematodes in East Africa
Wednesday, February 16, 2022
COVID Vaccine Stories III: The Inequity Factor
By now all (scientists included) are resigned to the fact that COVID-19 is here to stay and that we must learn to live with it. We may not be able to eradicate SARS-CoV-2 as we did smallpox and polio. The pandemic might eventually shrink to an endemic state which can be easily managed with vaccines. That again is a fervent hope. As of now the focus is to get everyone doubly vaccinated as fast as possible.
That a large percentage of global population is yet to be vaccinated, adds to the worry. This began as an economic issue. The Rich and the Powerful nations competed with each other to procure vaccine supplies for their citizens. They hijacked enough and more supplies while the poorer nations remained helpless, mute bystanders. It took time for the Rich to realise that unvaccinated populations are fertile grounds for new variants. In other words nobody is safe unless everybody is vaccinated.
| Courtesy:wikipedia |
Vaccinating entire global population is a daunting task indeed. Even if adequate amounts of vaccines are made available, as is the case now, logistics of the supplies reaching every remote corner before the expiry date remains a challenge. Most of the developing nations do have very robust healthcare networks in place while most of the underdeveloped nations don't. With the result that as of 14th February 2022, though globally 10.4 billion doses have been administered, 80% of African population remains unvaccinated.
Coronavirus will continue to mutate, at times in unpredictable ways. Still, the fact that there are several vaccines already in the market and many more in the pipeline is certainly "a cause for hope and optimism" as Nature Magazine summed up in its recent Editorial: "but with a hefty dose of realism: the virus will continue to circulate and change, and governments must continue to rely on the guidance and advice of scientists. We will not always be able to predict the virus's path but we must be ready to adapt with it."
REFERENCES
1. COVID-19 will continue but the end of the pandemic is near
2. No one is safe from COVID-19 until everyone is safe.
3. Tracking Coronavirus Vaccinations Around the World
4. Dear G20 leaders: Vaccine equity is a must for Africa
5. Coronavirus is here to stay
6. COVID is here to stay: countries must decide how to adapt
7. Achieving COVID-19 vaccine equity means overcoming hesitancy
Wednesday, January 12, 2022
Covid-19 Vaccine Stories: II: The Inimitable Cuban Style
When Covid-19 struck, Cuba knew it will have to fight alone, because the sixty year old economic embargo by the mighty United States prevented Cuba's access to US vaccines. Undeterred the scientists at the Finlay Institute of Vaccines, together with the Centre for Genetic Engg. and Biotechnology Havana rose to the occasion. In May 2021, The Guardian prophesied that Cuba could become the smallest country in the world to develop its own coronavirus vaccines. In spite of economic hardships, the country surged ahead. The prophesy came true. Cuban Vaccines Soberana 02 and Abdala registered +90% efficacy against Covid-19. Today more than 80% of Cuba's 11million population stands vaccinated and scientists are tweeking Soberana-02 to meet the challenge of the Omicron variant.
In Spanish Soberana means Sovereign and Abdala is a famous Cuban patriotic poem. The Mambuses are patriotic Cuban soldiers who have always fought for Cuba
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| Centre for Genetic Engg.and Biotechnology, Havana, Cuba |
Havana, is simpler, a different fragment of the spike protein adsorbed onto aluminium hydroxide and suspended in suitable medium. Such protein vaccines do not require extreme refrigeration and are cheap and easy to manufacture. There are several other candidates in the Cuban pipeline including a nasal vaccine Mambisa.
In Spanish Soberana means Sovereign and Abdala is a famous Cuban patriotic drama. The Mambises are those patriotic Cuban soldiers who defended Cuba on several occasions.
In the meanwhile Cuba has embarked on vaccine diplomacy by exporting Soberana-02 and Abdala to Venezuela, Nicargua, Iran and Vietnam. It would like to extend this gesture of comraderie to less privileged nations who are in dire need of the vaccine. For this World Health Organisation's has to give the nod.
Tailpiece
“Cubans either don’t meet the mark – or go way past it.”
(Words of General Máximo Gómez, a key figure in Cuba’s 19th-century wars of independence against Spain : Guardian 5th Jan. 2022)
REFERENCES
1. Cuba punches above its weight to develop its own Covid vaccines
2.Cuba soars to near top of COVID vaccination charts on decades-old bet
3. In world first, Cuba starts COVID-19 vaccine for toddlers
Wednesday, December 8, 2021
COVID-19 Vaccine Stories I : Modern(a) Twists
The whole World applauded when a unique Public-Private Partnership was forged. The US Governmental agency, National Institutes of Health (NIH) and Moderna the American pharmaceutical company joined forces to confront the COVID-19 pandemic. They began with a shared vision: to come up with a vaccine against the deadly virus in the shortest time possible. The two have been in partnership for about 4 years in matters of health. Everything went on as planned. National Institute of Allergy and infectious Diseases (NIAID) under the umbrella of NIH readily shared their laboratory findings with Moderna and then Lo and behold! a vaccine mRNA 1273 or Spikevax was in the market in record time.
| Moderna Covid-19 Vaccine Courtesy: wikipedia |
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| Moderna Headquarters, Cambridge, Massachusetts Courtesy: wikipedia |
Moderna was founded as ModeRNA Therapeutics in 2010. The name implies modified RNA the focus of the company. For Moderna it makes business sense to have full and exclusive ownership on the patent because the COVID-19 vaccine market is expected to be $19.5 billion in another 5 years. Add to this the fact that Moderna's product menu has only one item:. COVID-19 vaccine.
Tailpiece:
Reliefweb states: "Moderna’s Q3 profit before tax for 9 months ending September 30 is $7.8 billion on $11.2 billion revenue giving a pre-tax profit margin of 70 percent. The company projects full year 2021 sales to be “between $15 billion and $18 billion”. Using the lower end of the estimate —70 percent of $15 billion is $10.5 billion in profit for 2021. The vaccine is Moderna’s only commercial product."
REFERENCES:
1. Experimental Coronavirus vaccine highly effective
2. Immunogenicity and structures of a rationally designed prefusion MERS-CoV spike antigen: Jesper Pallesen et al (PNAS Aug 19, 2017)
3. What the Moderna–NIH COVID vaccine patent fight means for research
4. COVID-19 vaccine market set to touch $19.5bn by 2026
5. In shock move, US backs waiving patents on COVID vaccines
7. Moderna, escalating dispute with NIH, claims government had no role in key vaccine patent
Thursday, November 4, 2021
Time concrete turned Green
Obviously the concern is about the carbon footprint of concrete. According to a recent report, the annual global usage of concrete is roughly 30 billion tonnes. Going by the current trend, this will rise upwardly for decades to come. Concrete, an aqueous slurry of cement, sand and gravel can be poured and set in any form. Once set, the product has enormous strength, stability and durability with absolutely no maintenance cost. Over centuries concrete has inspired and dared architects and builders to dream big and build big.
| Burj Khalifa, Dubai |
Concrete is 10-15% cement, 15-20% water and the rest an aggregate of gravel and sand. To get high quality concrete, water to cement ratio must be kept low without compromising the workability of the mixture. The ingredients are mixed, set and cured at room temperature. Seems like a very benign process. So what exactly is our quarrel with concrete? Well our issue is not with concrete per se but with the cement in the formulation. Cement is made by the calcination limestone with clay at 1450 deg.C. This high temperature is achieved using fossil fuel, usually coal which holds a heavily tarnished environmental record. During the calcination process multiple reactions take place in sequential and parallel fashion. First of all limestone which is calcium carbonate, releases carbon dioxide and becomes calcium oxide and reacts with oxides and silicates of aluminium and iron in the clay. The resultant product is cement, a complex mixture of tricalcium silicate (3CaO · SiO2), dicalcium silicate (2CaO · SiO2), tricalcium aluminate (3CaO · Al2O3), and a tetra-calcium aluminoferrite (4CaO · Al2O3Fe2O3) with small amounts of gypsum (CaSO4 ). This mixture called clinker is enhanced with additives if needed and then pulvarized to yield cement. This is the conventional cement usually referred to as Portland cement.
Thus cement manufacturing is one of the most energy intensive industries. It is one of the highest consumers of fossil fuels. Approximately 3 GJ of thermal energy and 110 kWh of electrical energy are needed to produce 1 tonne of cement. In terms of CO2 emissions too the cement industry tops the list with 600 kilograms of carbon dioxide released into the atmosphere for every tonne of cement manufactured . And that indeed is our concern.
Another question pops up here : do we have alternatives for limestone? Perhaps we do. Fly ash, the residue from the coal plants is a possible candidate and so is slag from the iron and steel industry. Fly ash is the fine residue after the combustion of coal while slag is the residue from iron blast furnaces. Both contain oxides of silicon, aluminum, iron and calcium and hence bear an overall chemical resemblance to Portland cement but not in precise composition or structure. Nevertheless studies have shown that blending conventional cement with 20% of either fly ash or slag doesn't adversely affect the properties of the final concrete. Currently blended cement formulations with varying fly ash/slag content are available in the market. However here is the catch: with a global consensus shaping up to phase out coal by 2070, future availability of fly ash will eventually be an issue. Slag has its own disadvantages regarding workability,permeability and durability which are being looked into.
Tailpiece:
Burj Khalifa : Having consumed 110,000 tonnes of concrete, Burj Khalifa, currently the tallest building on Earth, is guilty of releasing 660,000,00 kilograms of carbon dioxide into our atmosphere. The environmental cost factor of a total of 55,000 tonnes of steel and 103,000 square metres of glass remains to be calculated.
References:
1. Concrete needs to lose its colossal carbon footprint: Nature,30 Sept.2021
2. Why fossil fuel subsidies are so hard to kill?
3. Zimmer, M., Kuhanathan, A. & Badre, A. Abolishing Fuel Subsidies in a Green and Just Transition (Allianz, 2021).
4. Agenda for CoP26: Why phasing out coal will not be decided in a jiffy?
4.Optimizing-the-use-of-fly-ash-concrete.pdf
6. Sustainable cement: the simple switch that could massively cut global carbon emissions
7.


