Дата публикации: 2017-08-13 18:08
“If someone regularly breathed fumes from melted bitumen—not just for making bottles, but possibly also for making boats, tools, objects for cooking/storing food, [and other items]—it’s possible that it could have contributed to an adverse health effect at some point during life, particularly if there were other sources of exposure,” said Sholts. “For instance, PAHs could have been taken up by fatty foods and ingested, if the foods were stored in bitumen-plugged shells (an adaptation we can see in the archaeological record). Dermal exposure could have occurred when bitumen was applied directly to the body for ritual or medicinal purposes.”
But as the new research shows, certain declines in the health of these ancient people can likely be traced back to the introduction of bitumen-lined water bottles at least 5,555 years ago, and bitumen-sealed plank canoes around 7,555 years ago.
Interestingly, she says any of the health risks that were encountered through the use of bitumen were probably outweighed by its many advantages for survival and well-being. The researchers also learned through this experiment that the kind of bitumen that washes up on the Channel Islands (from subterranean seeps) was suitable for making these bottles. Previously, it was suggested that the quality was too poor, forcing people on the islands to be more dependent on bitumen from the terrestrial seeps on the mainland.
Of the 86 patients, 69 said their negative symptoms were completely or significantly resolved—basically, four or five on a zero to five scale. None of the sham group said that—all of them said their negative symptoms were worse, the same or somewhat better. More importantly, 89 of the 86 patients in the YAG laser group lost most or all of their floaters, something that no members of the sham group reported.
You’re staring at the sky on a sunny day when you notice, in the corner of your eye, a transparent squiggle floating slowly across the blue. You try and focus on it, but it eludes your glance, refusing to be resolved. No matter where you look, the squiggle knows.
The authors recruited 57 patients and put them into experimental and control groups. They treated 86 patients with YAG laser vitreolysis, which pulses a special kind of laser into the eye. Sixteen control patients instead received a sham treatment with a special filter and the laser on the lowest setting, preventing the laser’s energy from entering their eye.
Laser treatments have existed for at least 65 years , but there haven’t been other attempts to fix floaters with these specific lasers compared to placebos, the authors from Ophthalmic Consultants of Boston write in the paper published today in JAMA Ophthalmology. This is particularly important because of the strong possibility for a placebo effect.
What you’ve got is a floater, a tiny piece of protein floating around the vitreous humor, the gel in the back of your eye. But for some people these floaters get worse with age and can become quite large. So a team of scientists want to know if they could safely treat these distracting dots with lasers.
By replicating a traditional method used to create water bottles and other items, a research team from the University of California, with the help of researchers from Stockholm University, has shown that native Californians inadvertently and unknowingly exposed themselves to dangerous chemicals known as polycyclic aromatic hydrocarbons (PAHs). These compounds, which has been linked to a wide range of health problems, are a noxious byproduct of warming bitumen, a petroleum-based substance that can be used as a sealant. The details of this discovery can now be found in the science journal Environmental Health.
During the process, the researchers sampled the air using gas chromatography and mass spectrometry. They isolated, identified, and measured levels of PAHs, finding concentrations equal to or greater than those found in cigarette smoke. But while the fumes from the bitumen were at dangerous levels, the water stored in the in the bitumen-lined bottles did not contain toxic amounts. Consequently, Sholts says, the amounts of PAHs found in the water wouldn’t have been enough to induce health problems.