Science, Art, Litt, Science based Art & Science Communication
My answers to questions on science - 1
Q: Which bacteria removes copper from low-grade copper ore?
Bioleaching has the advantage of being a relatively green process. The process itself produces no carbon emissions as no fuels are burned. There is also less necessity for land clearance as land is not required to grow plants. It also doesn’t require land that already contains high concentrations of low grade ores (1)
The main disadvantage of this process is again the time taken for it to work. Bacteria require time to break down the low grade ore and form leachates. To produce useful quantities of copper compounds, a long enough amount of time must be allowed for the bacteria to do their job.
There are also some bacteria that were isolated from copper ores and they too are sulfur- and iron-oxidizers: Acidithiobacillus ferrooxidans and Sulfobacillus thermosulfidooxidans, the iron-oxidizers of Leptospirillum ferriphilum and Ferroplasma sp., the sulfur-oxidizers of Acidithiobacillus caldus and Acidithiobacillus thiooxidans (3).
Footnotes:
- Biological Methods of Extracting Metals Worksheets, Questions, and ...
- Biomining: How microbes help to mine copper
- https://www.sciencedirect.com/science/article/abs/pii/S096085242030...
Q: Can problems with bone health be inherited?
Krishna: Yes! However, while genetic factors play a significant role in determining bone mass, controllable lifestyle factors such as diet and physical activity can mean the difference between a frail and strong skeleton.
Normal bone mass and strength is controlled by many genetic elements working in concert. The tendency to develop bone diseases like osteoporosis and Paget’s disease also appears to be due to genetic factors, although this tendency may also be influenced by environmental factors.
The main determinants of bone health are (1):
- While genetic factors play a significant role in determining bone mass, controllable lifestyle factors such as diet and physical activity can mean the difference between a frail and strong skeleton.
- Calcium has been singled out as a major public health concern today because it is critically important to bone health and the average American consumes levels of calcium that are far below the amount recommended for optimal bone health.
- Vitamin D is important for good bone health because it aids in the absorption and utilization of calcium. There is a high prevalence of vitamin D insufficiency in nursing home residents, hospitalized patients, and adults with hip fractures.
- Physical activity is important for bone health throughout life. It helps to increase or preserve bone mass and to reduce the risk of falling. All types of physical activity can contribute to bone health, albeit in different ways.
- Maintaining a healthy body weight is important for bone health throughout life. Being underweight raises the risk of fracture and bone loss. Weight loss is associated with bone loss as well, although adequate diet and physical activity may reduce this loss.
- Fractures are commonly caused by falls, and thus fall prevention offers another opportunity to protect bones, particularly in those over age 60. Several specific approaches have demonstrated benefits, including muscle strengthening and balance retraining, professional home hazard assessment and modification, and stopping or reducing psychotropic medications.
- Reproductive issues can affect bone health. Pregnancy and lactation generally do not harm the skeleton of healthy adult women. Amenorrhea (cessation of menstrual periods) after the onset of puberty and before menopause is a very serious threat to bone health and needs to be attended to by individuals and their health care providers.
- Several medical conditions and prescription medications can affect bone health through various mechanisms, and health care professionals should treat the presence of such conditions and the use of such medications as a potential red flag that signals the need for further assessment of bone health and other risk factors for bone disease.
- Smoking can reduce bone mass and increase fracture risk and should be avoided for a variety of health reasons. Heavy alcohol use has been associated with reduced bone mass and increased fracture risk.
A study (2) explained that anywhere from 25 to 85 percent of our BMD (bone mineral density) and other skeletal characteristics may be inherited. Other genes associated with BMD and osteoporosis include the genes VDR, ESR1 and ESR2, COL1A1, and STAT1.
Another study (3)of over 420,000 people with osteoporosis, then followed with experiments on mice, suggested the DAAM2 gene was associated with decreased bone strength.
Researchers are finding that your risk for osteoporosis and fractures may increase if one of your parents has a history of osteoporosis or hip fracture. Changes to hormones. Low levels of certain hormones can increase your chances of developing osteoporosis (4).
Osteoporosis Source: Google images
Hypophosphatasia is an inherited disorder that affects the development of bones and teeth. This condition disrupts a process called mineralization, in which minerals such as calcium and phosphorus are deposited in developing bones and teeth. Mineralization is critical for the formation of bones that are strong and rigid and teeth that can withstand chewing and grinding.
The signs and symptoms of hypophosphatasia vary widely and can appear anywhere from before birth to adulthood. The most severe forms of the disorder tend to occur before birth and in early infancy. Hypophosphatasia weakens and softens the bones, causing skeletal abnormalities similar to another childhood bone disorder called rickets. Affected infants are born with short limbs, an abnormally shaped chest, and soft skull bones. Additional complications in infancy include poor feeding and a failure to gain weight, respiratory problems, and high levels of calcium in the blood (hypercalcemia), which can lead to recurrent vomiting and kidney problems. These complications are life-threatening in some cases (5).
Brittle bone disease is a lifelong genetic disorder that causes your bones to break very easily, usually without any type of injury, as from a fall. Your doctor may also call it osteogenesis imperfecta. It’s caused by a defect in a gene that is supposed to make a substance called Collagen. It is a protein in your body that forms and strengthens bones. If you don’t have enough of it, your bones become very weak and will break easily (6).
It's not very clear what causes bone cancer, but doctors have found certain factors are associated with an increased risk, including: Inherited genetic syndromes. Certain rare genetic syndromes passed through families increase the risk of bone cancer, including Li-Fraumeni syndrome and hereditary retinoblastoma(7).
So scientific research says there are a large number of inherited factors that affect the bone health.
Footnotes:
- Determinants of Bone Health
- How genomics has informed our understanding of the pathogenesis of ...
- An atlas of genetic influences on osteoporosis in humans and mice -...
- Osteoporosis
- Hypophosphatasia: MedlinePlus Genetics
- What Is Brittle Bone Disease?
- Bone cancer - Symptoms and causes
Q: How can thyroid affect a pregnant woman and baby in the womb?
Krishna:
Thyroid hormones transfer from mother to embryo by placental cord that have deiodinase enzyme for transformation T4 to T3. But in second and third trimester, in addition to mother, the embryo can produce thyroid hormones. In fact the embryo during 10th to 12th of pregnancy gains the ability of thyroid hormones production . So any disorder in thyroid gland function in the first trimester of pregnancy can influence the embryo (2).
Q: What are the health effects of exposure to ionizing radiation, and how do they vary depending on the dose and duration of exposure?
Krishna: Excessive exposure to radiation may damage living tissues and organs, depending on the amount of radiation received (i.e. the dose). The extent of the potential damage depends on several factors, including:
- the type of radiation;
- the sensitivity of the affected tissues and organs;
- the route and duration of exposure;
- the radioactive isotopes involved; and
- the individual characteristics of the exposed person (such as age, gender and underlying health condition).
The risk of developing adverse health effects depends on the radiation dose. The higher the dose, the higher the risk of adverse effects. If the radiation dose is low or is delivered over a long period of time, the risk is substantially lower because the damage to cells and molecules will be repaired by the body.
At very high doses, radiation can impair the functioning of tissues and organs and produce acute effects such as nausea and vomiting, skin redness, hair loss, acute radiation syndrome, local radiation injuries (also known as radiation burns), or even death (1).
When ionizing radiation interacts with cells, it can cause damage to the cells and genetic material (i.e., deoxyribonucleic acid, or DNA). If not properly repaired, this damage can result in the death of the cell or potentially harmful changes in the DNA (i.e., mutations).
Health effects from radiation doses can be grouped into two categories: deterministic and stochastic. Deterministic effects occur after a threshold dose is reached, meaning at dose below the threshold are not expected to cause the particular effect. The severity of the effect increases with the dose. Skin reddening (erythema) is an example of a deterministic effect with a threshold dose of approximately 300 rad (3 Gy). Although it may not accurately describe all deterministic health effects, they are sometimes described as "short-term" health effects.
Stochastic effects occur by statistical chance. The probability of the effect occurring in a population increases with the dose received, and the severity of the effect does not depend on the dose. Cancer is the main stochastic effect that can result from radiation dose, often many years following the exposure. Stochastic health effects are assumed not to have a threshold dose below which they do not occur. This is the reason that no level of radiation dose is considered to be completely "safe" and why doses should always be kept as low as reasonably achievable (ALARA). Although it may not accurately describe all stochastic health effects, they are sometimes described as "long-term" health effects(2)
Some workers, such as radiology department workers, may be repeatedly exposed to low levels of ionizing radiation over the course of their careers. The resulting dose levels are almost always below the threshold doses needed for deterministic health effects to occur. Stochastic health effects, such as cancer, may occur years following the radiation dose. The probability of an adverse health effect occurring is proportional to the radiation dose received.
Scientific studies have shown significant associations between cancer and radiation dose levels of about 10 rem (0.1 Sv) or greater, with the cancer risk increasing as the radiation dose increases. For low-level radiation exposure (i.e., whole body doses less than about 10 rem (0.1 Sv)), statistical limitations in studies have made cancer risk assessment more difficult(3). there is likely no safe dose level (i.e., threshold), and that even low radiation doses have the potential to cause a small increase in cancer risk(3)
Deterministic health effects can occur when a part of the body receives a radiation dose that exceeds the threshold for that health effect. Some of these health effects (e.g., skin reddening/burns) can occur after a short delay of 1 4 weeks after an acute radiation dose is received. In most controlled occupational settings, workers are not likely to receive radiation doses that would result in such effects.
At lower doses, particularly below 50 rad (0.5 Gy), radiation may cause short-term changes in blood chemistry, including the count, structure, and function of various types of blood cells. Other deterministic effects at lower radiation doses include:
- Birth defects at doses at or above about 10–20 rad (0.1–0.2 Gy) to the embryo/fetus.4
- Temporary sterility at doses at or above 15 rad (0.15 Gy) to the testes in a brief single exposure.5
- Detectable lens opacities (which, when they cause vision problems, are known as cataracts) at acute doses at or above 50 rad (0.5 Gy) to the lens of the eye7
- Total body exposure of 100 roentgens/rad or 1 Gray unit (Gy) causes radiation sickness.
- Total body exposure of 400 roentgens/rad (or 4 Gy) causes radiation sickness and death in half of the individuals who are exposed. Without medical treatment, nearly everyone who receives more than this amount of radiation will die within 30 days.
- 100,000 roentgens/rad (1,000 Gy) causes almost immediate unconsciousness and death within an hour. (9)
8. U.S. Department of Health and Human Services (HHS), Centers for Disease Control and Prevention (CDC), "Acute Radiation Syndrome: A Fact Sheet for Physicians."
9. https://medlineplus.gov/ency/article/000026.htm#:~:text=Without%20m....
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