Egypt unveils tomb of ancient priestess
Egyptian archaeologists on Saturday unveiled the tomb of an Old Kingdom priestess adorned with well-preserved and rare wall paintings. Antiquities Minister Khaled al-Enany told reporters ...
Science
Earthquakes from the oil and gas industry are plaguing Oklahoma
In 2008, the state recorded only one earthquake of magnitude 3 or greater (big enough to be felt by people locally). In 2015, the number of earthquakes of equivalent magnitude peaked at a staggering 903. Oklahoma has been transformed from a seismic dead zone to a hotspot in less than a decade.
Scientists attribute this unprecedented increase in seismicity to the oil and gas industry injecting its wastewater (known as “saltwater”) deep underground. In a study published in the journal Science, my colleagues and I have now shown that the size of these man-made earthquakes is strongly linked to the depth at which the saltwater is injected. As a result, reducing the depth of injections could significantly reduce the likelihood of larger, damaging earthquakes.
There are now more than 10,000 injection wells dotted across Oklahoma. This includes both oil recovery wells and wells used to dispose of the saltwater that is an unwanted byproduct of the oil and gas extraction process. The water is injected deep underground, typically at depths of 1km to 2km. This deliberately is well below the level of fresh ground water supplies in order to avoid contamination. Since 2011, well operators have injected on average 2.3 billion barrels of fluid a year into layers of sedimentary rock deep underground.
The link between Oklahoma’s earthquakes and wastewater disposal was firmly established by a 2013 study that showed a strong association between the injection zone and earthquakes, including the 2011 magnitude 5.7 Prague event.
Since 2015, some new regulations have led to an overall decline in the number of earthquakes. But the total seismic energy (the “moment”) has not dropped as significantly as expected. In fact, a number of powerful earthquakes including Pawnee (magnitude 5.8) – the largest in state history – struck in 2016, after the new regulations came into effect. There is also some concern that there have only been fewer earthquakes because a lower oil price has led to less oil production and saltwater disposal, and that seismicity would increase if the oil price rises again.
Modelling the earthquakes
Our new study sheds light on the complexity of Oklahoma’s induced seismicity. We created a computer model of the relationship between seismic activity, geology and injection operations using six years’ worth of fluid disposal data from across the state. It shows that the more saltwater is injected and the greater the depth it goes to, the larger the resulting earthquake.
The injection is even more likely to cause earthquakes at depths where layered sedimentary rocks meet the crystalline “basement” rocks below them, at depths of between 1km and 6km. This shouldn’t be surprising because we know that when fluid gets into the spaces within rocks it can considerably weaken them. Pressurised fluids can effectively lubricate ancient fault zones that may have locked-in stresses built up over time, making them more prone to failure.
We hope our approach could help regulators test the effects of new regulations and the potential impact of new injection wells. Another major benefit is that our model can easily be updated as more data becomes available. This is important as different areas have become seismically active over time. This type of model could be used to identify when certain locations become more vulnerable to earthquakes, and help manage seismicity in Oklahoma and other areas where saltwater injection takes place.Raising injection well depths further above the basement rocks in key areas could significantly reduce the annual energy released by earthquakes, in turn making larger earthquakes less likely. Current regulations can require operators to either reduce injection or raise the depth at which wells inject relative to the crystalline basement, but often the amount is not given or not based on scientific evidence.
Most people involved, including Erin Brockovich, admit “effective, immediate and realistic steps” are required to tackle Oklahoma’s earthquake problem. The science of saltwater disposal can provide some practicable solutions, and our study is just the first step. We need the support of researchers, operators and regulators, to ensure this approach has a lasting impact on reducing man-made earthquakes.
By Thomas Gernon, Associate Professor in Earth Science, University of Southampton
This article was originally published on The Conversation. Read the original article.
Promising male birth control pill has its origin in an arrow poison
State of the search
While the birth control pill has been available to women in the United States for nearly six decades – and FDA-approved for contraceptive use since 1960 – an oral contraceptive for men has not yet come to market. The pill has provided women with safe, effective and reversible options for birth control, while options for men have been stuck in a rut.
Today, men have just two choices when it comes to birth control: condoms or a vasectomy. Together, these two methods account for just 30 percent of contraception used, leaving the remaining 70 percent of contraceptive methods to women. An estimated 500,000 American men opt for a vasectomy each year – a small number given the need for contraception. Vasectomy is an invasive procedure to do that’s also difficult and invasive to reverse.
When it comes to birth control options for men, the need is clear. Unplanned pregnancy rates remain high across the globe. It’s time for more options.
Hormonal versus nonhormonal
Researchers are exploring both hormonal and nonhormonal options for male birth control pills. Current hormonal agents under study involve the sex steroids progestins and testosterone.
While the male hormonal birth control pill option is in clinical human trials and likely closer to market, it has several potential side effects: In addition to potentially causing weight gain and changes in libido, it has the ability to lower the levels of good cholesterol (HDL-C) in men, which could negatively affect the heart health of users. The long-term effects of using hormones for male oral contraception are unknown, and it will likely be decades before this information is available.
Here at the University of Minnesota, my colleagues and I have focused on nonhormonal contraception methods that work by targeting sperm motility – biology-speak for the sperms’ ability to move or swim effectively. Good motility is a necessary condition for fertilizing a female egg.
In collaboration with Gustavo Blanco at the University of Kansas, we’ve homed in on ouabain: a toxic substance produced by two types of African plants. Mammals also produce ouabain in their bodies, though at lower nonlethal levels that scientists think can help control blood pressure. In fact, physicians have used ouabain in very small doses to treat patients with heart arrhythmias or suffering from heart attacks.
From toxin to contraceptive
Researchers know that ouabain disrupts the passage of sodium and potassium ions through cell membranes; it interferes with the proper function of proteins that transport the ions in and out of cells. Some of the ion-transporting protein subunits targeted by ouabain are found in cardiac tissue – its ability to disrupt proper heart function is what makes ouabain a deadly poison. But ouabain also affects another type of transporter subunit called α4, which is found only in sperm cells. This protein is known to be critical in fertility — at least in male mice.
For 10 years, my colleagues and I have been studying ouabain as a potential breakthrough in our quest for a male birth control pill. However, ouabain by itself isn’t an option as a contraceptive because of the risk of heart damage. So we set out to design ouabain analogs – versions of the molecule that are more likely to bind to the α4 protein in sperm than other subunits in heart tissue.
In the lab, we used the techniques of medicinal chemistry to create a derivative of ouabain that is good at zeroing in on the α4 transporter in sperm cells in rats. Once bound to those cells, it interferes with the sperms’ ability to swim – essential to its role in fertilizing an egg. Our new compound showed no toxicity in rats.
Because the α4 transporter is found only on mature sperm cells, the contraceptive effect should be reversible – sperm cells produced after stopping the treatment presumably won’t be affected. Ouabain may also offer men a birth control pill option with fewer systemic side effects than hormonal options.
Next steps on the road to drug discovery
Our results are promising because our candidate molecule, unlike ouabain, is nontoxic in rats. Our modification is a big step forward in the process of developing a nonhormonal male birth control pill. But there’s a lot left to do before men can buy this contraceptive at the pharmacy.
After our ouabain analog showed promise in rat studies at reducing sperm motility, future studies will focus on the effectiveness of our lead compound as an actual contraceptive in animals. We need to prove that a reduction in sperm movement translates into a drop in egg fertilization.
Then, we’ll begin the standard steps in drug discovery such as toxicology and safety pharmacology studies as we advance toward planning and conducting clinical trials. Our team is already taking the next step to test our compound in animal mating trials. If things continue as planned, we hope to get to human clinical trials within five years.
Reversible, effective male birth control is within sight. World Health Organization numbers suggest that reducing sperm motility by 50 percent or less is sufficient to temporarily make a man infertile. Our ongoing research brings us one step closer to expanding the options for male birth control, providing the world’s 7.6 billion people with a much-needed option for safe and reversible contraception.
By Gunda Georg, Professor of Medicinal Chemistry and Director of the Institute for Therapeutics Discovery and Development, University of Minnesota; Jon Hawkinson, Research Professor of Medicinal Chemistry and Associate Program Director of the Institute for Therapeutics Discovery and Development, University of Minnesota, and Shameem Syeda, Principal Scientist at the Institute for Therapeutics Discovery and Development, University of Minnesota
This article was originally published on The Conversation. Read the original article.