Over the course of the pandemic in the U. S, more than 2 million children aged have become infected, more than have been hospitalized, and more than have died, making COVID one of the top 10 causes of pediatric deaths in this age group over the past year. These include complaints of brain fog, fatigue, trouble breathing, fever, headache, muscle and joint pains, abdominal pain, mood swings and even psychiatric disorders.
Symptoms typically last from weeks in children, with some reporting symptoms that persist for many months. Second, children are increasingly recognized as vectors who can bring infection into the house , potentially transmitting infection to vulnerable household members. Finally, we have all seen the mayhem that results when one child in the classroom becomes infected with COVID and the other students get sent home to quarantine — across the U.
We now have an extraordinarily effective vaccine with more than 90 percent efficacy at preventing symptomatic infection. Vaccinating children will boost our countrywide vaccination rate which is trailing many countries after an early start.
Nevertheless, there are still many questions and concerns that parents have as the vaccine gets rolled out. I will address six of them here. Even though this is a relatively new vaccine, the technology is not new. By now it has been more than a year and a half since the Pfizer trials began in March , and more than 7 billion doses have already been administered globally, including in This is not how mRNA works.
DNA is present in the cell's nucleus. The mRNA only stays in the outside cytoplasm , gets destroyed and never enters the inner sanctum of the nucleus. Furthermore, for the mRNA to be ever integrated into DNA, it requires a special enzyme called reverse transcriptase which humans don't have.
Pieces of spike proteins get displayed on the outside of our cells and our body makes protective antibodies that then protects us handily against the future real virus if it were ever to enter our or our children's bodies. Unlike medications that are taken daily or periodically and can build up over time, the mRNA in the Pfizer vaccine is evanescent. It literally is just the messenger that is what the "m" in mRNA stands for and the messenger quickly disappears.
Our cells break down and destroy the mRNA within a few days after receiving the instructions to make the virus spike proteins. The presence of these fragments of the virus note this is not "live" virus prompts our immune system to generate protective antibodies to the real thing. Our bodies break down mRNA all the time in normal cellular processes — this is nothing new. What the transience of the delivery system means is that most of the effects of the mRNA vaccines are expected to be more immediate sore arm, redness at the site, fever, chills etc.
A severe allergic response has been reported to occur in some generally within the first 15 minutes, is very rare, and everyone gets observed for that as part of standard vaccine administration. Even with the very uncommon complication of myocarditis inflammation of the heart muscle and pericarditis inflammation of the lining of the heart seen primarily in young men under the age of 30 following mRNA vaccines, these typically happen within days to 2 weeks and many return to work or school in days.
In the year history of pediatric and adult vaccines , dangerous complications happen in the first two months. There have been millions of adolescents as young as 12 years and thousands in the initial trial of children aged who have already received the vaccine and are well beyond the two-month period of observation.
There is no biological reason to believe that younger children will have a different long-term side effect profile compared to adolescents or adults. Although the Pfizer trial in children aged was relatively small, it was big enough to give us statistical confidence in assessing safety and efficacy outcomes.
Scientists spend a lot of time determining the right sample size of a study during the design phase. On one hand, you want to conduct the study efficiently so that resources are used in a cost-effective way and that you get a timely answer, especially in a fast-moving pandemic.
On the other hand, you want to make sure you have enough sample size so that you can answer the question confidently as to whether the intervention works and whether there are adverse effects. The more profound the effect size of the intervention in this case the vaccine , the fewer the numbers of children needed in the trials. Statistics help investigators determine whether the results seen would have appeared by chance or not.
In this case, the effect was real and impressive. Over 3, children around the world have received the vaccines through the trials alone with no serious side effects detected. The first press release reported that the immune response in children aged was similar at one-third the vaccine dose to the response in the comparator group aged years old.
Extrapolating clinical efficacy results from immune response measurements " immunobridging " study would already have been acceptable if this was the only data. This is a standard trial design for many pediatric vaccines. Vaccines are first tested in the lab, followed by animals then adults. Only when deemed safe in adults and various regulatory bodies have signed off, do the pediatric vaccine trials commence.
Because children's immune systems and bodies are in a constant state of development, the vaccines must be right-sized. Investigators typically conduct "age de-escalation" studies in various age groups.
The lowest dose is first tried so see if that is effective, then the dose is increased gradually as needed. Immune response is the easiest, safest and most efficient way to test the efficacy of pediatric vaccines. This is a typical size and design of a childhood vaccine seeking regulatory approval. There is no reason to think that the clinical efficacy would be any different in children vs.
Although this was primarily designed as an "immunobridging" study, the initial immunologic response data was followed by real clinical outcomes in this population. Reporting on the outcomes of 2, children in the randomized controlled trial, the vaccine was Myocarditis inflammation of the heart muscle and pericarditis inflammation of the lining of the heart have been associated with receipt of the mRNA vaccines , particularly among male adolescents and young adults, typically within a few days after receiving the second dose.
But this is very rare. For every million vaccine recipients, you would expect 41 cases in males, and 4 cases in females aged years-old. The risk in older age groups is substantially lower. Second, Close rejects the claim that two helium-3 nuclei could realistically be made to fuse with each other to produce deuterium, an alpha particle and energy. When running, it contains a spherical plasma roughly 10 centimeters in diameter that can produce sustained fusion with million reactions per second.
To produce a milliwatt of power, unfortunately, the reactor consumes a kilowatt. We run deuterium-He3 fusion reactions daily, so we are very familiar with that reaction. We are also doing He3-He3 because if we can control that, it will have immense potential. Our IEC devices, on the other hand, are tabletop-sized, and during our deuterium-He3 runs, we do get some neutrons produced by side reaction with deuterium.
More significant is the He3-He3 fusion reaction that Kulcinski and his assistants produce with their IEC-based reactor. Second, the protons it produces—unlike the neutrons produced by deuterium-tritium reactions—possess charges and can be contained using electric and magnetic fields, which in turn results in direct electricity generation. Kulcinski says that one of his graduate assistants at the Fusion Technology Institute is working on a solid-state device to capture the protons and convert their energy directly into electricity.
So forget it. That said, if pure He3-based fusion power is realizable, it would have immense advantages. A new simulation shows that when the DART mission hits the target asteroid, it could send it spinning and wobbling in a dramatic way.
The Decadal Survey, expected at the end of September, sets the tone for a new era of space exploration. Quantities as small as 20 ppb may seem too trivial to consider. Because the concentration of helium-3 is extremely low, it would be necessary to process large amounts of rock and soil to isolate the material.
Digging a patch of lunar surface roughly three-quarters of a square mile to a depth of about 9 ft. Although considerable lunar soil would have to be processed, the mining costs would not be high by terrestrial standards. Automated machines might perform the work. Extracting the isotope would not be particularly difficult. Heating and agitation release gases trapped in the soil. As the vapors are cooled to absolute zero, the various gases present sequentially separate out of the mix.
In the final step, special membranes would separate helium-3 from ordinary helium. The second-generation approach to controlled fusion power involves combining deuterium and helium This reaction produces a high-energy proton positively charged hydrogen ion and a helium-4 ion alpha particle.
The most important potential advantage of this fusion reaction for power production as well as other applications lies in its compatibility with the use of electrostatic fields to control fuel ions and the fusion protons. Protons, as positively charged particles, can be converted directly into electricity, through use of solid-state conversion materials as well as other techniques.
Potential conversion efficiencies of 70 percent may be possible, as there is no need to convert proton energy to heat in order to drive turbine-powered generators. Fusion power plants operating on deuterium and helium-3 would offer lower capital and operating costs than their competitors due to less technical complexity, higher conversion efficiency, smaller size, the absence of radioactive fuel, no air or water pollution, and only low-level radioactive waste disposal requirements.
Financial breakeven at today's wholesale electricity prices 5 cents per kilowatt-hour would occur after five megawatt plants were on line, replacing old conventional plants or meeting new demand. New Spacecraft Perhaps the most daunting challenge to mining the moon is designing the spacecraft to carry the hardware and crew to the lunar surface. The Apollo Saturn V spacecraft remains the benchmark for a reliable, heavy-lift moon rocket. Capable of lifting 50 tons to the moon, Saturn V 's remain the largest spacecraft ever used.
In the 40 years since the spacecraft's development, vast improvements in spacecraft technology have occurred. Returning to the moon would be a worthwhile pursuit even if obtaining helium-3 were the only goal. But over time the pioneering venture would pay more valuable dividends.
Settlements established for helium-3 mining would branch out into other activities that support space exploration. Even with the next generation of Saturns, it will not be economical to lift the massive quantities of oxygen, water and structural materials needed to create permanent human settlements in space. We must acquire the technical skills to extract these vital materials from locally available resources.
Mining the moon for helium-3 would offer a unique opportunity to acquire those resources as byproducts. Other opportunities might be possible through the sale of low-cost access to space.
These additional, launch-related businesses will include providing services for government-funded lunar and planetary exploration, astronomical observatories, national defense, and long-term, on-call protection from the impacts of asteroids and comets. Space and lunar tourism also will be enabled by the existence of low-cost, highly reliable rockets.
With such tremendous business potential, the entrepreneurial private sector should support a return to the moon, this time to stay. Living Off The Land Exploration of the solar system will be fueled by materials found scattered across asteroids, moons and planets. Moon The discovery of a helium isotope, helium-3, on the moon has given scientists ideas on how to produce electricity far more efficiently than with hydrocarbons or current nuclear plants.
The large amounts of energy would come without danger of releasing radioactive substances into the atmosphere. Mining the lunar surface would not be cheap; the investment would be comparable to building a major transcontinental pipeline. Mars Studies conducted by NASA and others have determined that water, rocket propellant and chemicals needed to sustain a human outpost could be manufactured from martian soil and ice caps right.
Future astronauts might set up production plants that expand as others arrive. Eventually, the Mars base could become a resupply base. Asteroids Scientists believe these leftovers of the solar system's formation, floating between the orbits of Jupiter and Mars, may contain rare elements and water. Mining these rocks, some as big as mountains, will be neither easy nor cheap. Using technologies previously developed to extract precious materials from the moon or Mars could make asteroids an attractive target, especially for a permanent human colony on the red planet.
Astronauts would first practice rendezvous with asteroids. Then, after studying them, crews would return with mining equipment.
Excavated ore could be trucked to a martian outpost.
0コメント