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COVID-19: antibodies in the blood of patients fade rapidly after symptoms subside, study finds

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covid 19 antibodies in the blood of patients fade rapidly after symptoms subside study finds

Antibodies made by the body to fight COVID-19 — the transfusion of which is being trialled as a treatment for other, more severe patients — fade rapidly after recovery.

Experts from Canada studied the blood of recovering coronavirus patients, finding that the extent of the immune defences drop 6–10 weeks after their first symptoms.

Plasma transfusions have not been proven as a treatment yet in randomised trials, but small retrospective studies have hinted that they may reduce illness severity.

If so-called ‘convalescent plasma’ is proven to be beneficial, this means that there is only a short window of opportunity for it to be donated, the researchers warned. 

Donors must wait two weeks after symptoms subside before giving blood — to ensure viral particles are gone — and symptoms typically last two weeks before that.

Given this, the time frame for plasma donation could be as short as just a fortnight. 

Antibodies made by the body to fight COVID-19 — the transfusion of which is being trialled as a treatment for other, more severe patients — fade rapidly after recovery. Pictured, a recovering coronavirus patient donated blood plasma for transfusion into a patient with a severe case

Antibodies made by the body to fight COVID-19 — the transfusion of which is being trialled as a treatment for other, more severe patients — fade rapidly after recovery. Pictured, a recovering coronavirus patient donated blood plasma for transfusion into a patient with a severe case

Antibodies made by the body to fight COVID-19 — the transfusion of which is being trialled as a treatment for other, more severe patients — fade rapidly after recovery. Pictured, a recovering coronavirus patient donated blood plasma for transfusion into a patient with a severe case

‘We don’t want to transfuse the virus, just transfuse the antibodies,’ said paper author and virologist Andrés Finzi of the University of Montreal, Canada.

‘But at the same time, our work shows that the capacity of the plasma to neutralize viral particles is going down during those first weeks.’

Key to the way in which SARS-CoV-2 attacks the body is the so-called spike proteins that cover the virus’ shell — and allow it to latch onto cells and invade them.

Antibodies made by the immune system, however, bind to the end of the spike proteins, preventing them from sticking to cells and rendering the virus ineffective.

Previous studies have suggested that antibodies that target the coronavirus spike protein peak in the blood at around 2–3 weeks after the onset of symptoms — and that the effectiveness of this defence may fade some 4–6 weeks after the same.

In their new study, Dr Finzi and colleagues monitored 31 recovering COVID-19 patients — analysing blood samples taken from each individual at monthly intervals.

For each sample, the researchers measured the levels of the antibodies — or ‘immunoglobulins’ — that act against the coronavirus spike protein, alongside testing the ability of these antibodies to neutralize the virus.

Key to the way in which SARS-CoV-2 attacks the body is the so-called spike proteins that cover the virus' shell (pictured) — and allow it to latch onto cells and invade them. Antibodies made by the immune system, however, bind to the end of the spike proteins, preventing them from sticking to cells and rendering the virus ineffective

Key to the way in which SARS-CoV-2 attacks the body is the so-called spike proteins that cover the virus' shell (pictured) — and allow it to latch onto cells and invade them. Antibodies made by the immune system, however, bind to the end of the spike proteins, preventing them from sticking to cells and rendering the virus ineffective

Key to the way in which SARS-CoV-2 attacks the body is the so-called spike proteins that cover the virus’ shell (pictured) — and allow it to latch onto cells and invade them. Antibodies made by the immune system, however, bind to the end of the spike proteins, preventing them from sticking to cells and rendering the virus ineffective

While the team observed variations among the patients, they found that in all cases the levels of three key immunoglobulins that target the binding site on the virus’ spike protein fell between 6–10 weeks after symptoms began.

As the levels of these antibodies fell, so did their capacity to neutralize the virus — and, by extension, their potential usefulness within a plasma transfusion. 

The full findings of the study were published in the journal mBio.

This post first appeared on dailymail.co.uk

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Australian caterpillar constructs a weapon in its head from shedded skulls to fight predators 

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australian caterpillar constructs a weapon in its head from shedded skulls to fight predators

A caterpillar native to Australia constructs a tower of its shedded skulls atop its head to use as a weapon against predators.

Called the gum-leaf skeletonizer, this insect is just two centimeters long and stacks its molted heads to create a horn like structure to swing at its enemies – specifically stink bugs.

The creatures have received a number of nicknames, from Unicorn Caterpillars to Mad Hatterpillars, but its scientific name is Uraba lugens.

Each gum-leaf skeletonizer molts up to 13 times before spinning a cocoon and turning into a moth.

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A caterpillar native to Australia constructs a tower of its shedded skulls atop its head to use as a weapon against predators

A caterpillar native to Australia constructs a tower of its shedded skulls atop its head to use as a weapon against predators

A caterpillar native to Australia constructs a tower of its shedded skulls atop its head to use as a weapon against predators

The caterpillar was first discovered in New Zealand in 1995 and received its name due to its habit of ‘skeletonizing’ gum leaves by feeding only on the green parts – leaving just the veins behind.

They are hairy creatures with shades of yellow and black, along with gray markings.

But what makes them stand out from the rest is the unique ‘hat’ on their heads consisting of former head capsules.

Dieter Hochuli, from the School of Life and Environmental Sciences at the University of Sydney, told Newsweek: ‘These guys create a tower of five, six or seven heads up there and they use them to deter things that are trying to eat them.’

Called the gum-leaf skeletonizer, this insect is just two centimeters long and stacks its molted heads to create a horn like structure to swing at its enemies ¿ specifically stink bugs

Called the gum-leaf skeletonizer, this insect is just two centimeters long and stacks its molted heads to create a horn like structure to swing at its enemies ¿ specifically stink bugs

Called the gum-leaf skeletonizer, this insect is just two centimeters long and stacks its molted heads to create a horn like structure to swing at its enemies – specifically stink bugs

And the caterpillar’s main threat is the stink bug.

The bug attacks the skeletonizer by sticking a needle from its mouth through the victim’s head.

The stink bug hits just the tower of empty heads, leaving it confused and opens a small window of opportunity for the caterpillar to escape.

However, these caterpillars are not as helpless as they seem – it is hazardous to both the environment and human health.

The creatures have received a number of nicknames, from Unicorn Caterpillars to Mad Hatterpillars, but its scientific name is Uraba lugens

The creatures have received a number of nicknames, from Unicorn Caterpillars to Mad Hatterpillars, but its scientific name is Uraba lugens

The creatures have received a number of nicknames, from Unicorn Caterpillars to Mad Hatterpillars, but its scientific name is Uraba lugens

Each gum-leaf skeletonizer molts up to 13 times before spinning a cocoon and turning into a moth

Each gum-leaf skeletonizer molts up to 13 times before spinning a cocoon and turning into a moth

Each gum-leaf skeletonizer molts up to 13 times before spinning a cocoon and turning into a moth

The hairs on its body cause a painful sting and skin irritation on contact with human skin.

Another dangerous caterpillar has been found to invade parts of the US that also pose a threat to humans.

Called a puss caterpillar, the furry creature is covered in venomous spikes that causes intense pain when touched, along with swelling, fever and symptoms of shock.

The hairy creature resides in the southern states and feeds on shade trees such as elm, oak and sycamore, but locals have spotted it roaming around parks and other structures.

However, there has been a recent ‘outbreak’ in parts of Virginia, following numerous sightings of what is called the most poisonous caterpillar in the US.

Officials note that the toxic caterpillar population is kept under control by natural enemies, but chemical insecticides will be deployed if necessary.

Virginia Department for Forestry has received numerous reports the caterpillar in a few eastern counties in the state, but has not specified exact locations.

Another dangerous caterpillar has been found to invade parts of the US that also pose a threat to humans. Called a puss caterpillar, the furry creature is covered in venomous spikes that causes intense pain when touched, along with swelling, fever and symptoms of shock

Another dangerous caterpillar has been found to invade parts of the US that also pose a threat to humans. Called a puss caterpillar, the furry creature is covered in venomous spikes that causes intense pain when touched, along with swelling, fever and symptoms of shock

Another dangerous caterpillar has been found to invade parts of the US that also pose a threat to humans. Called a puss caterpillar, the furry creature is covered in venomous spikes that causes intense pain when touched, along with swelling, fever and symptoms of shock

Crystal Spindel Gaston, a resident in Richmond, told The Daily Progress, about her encounter with the puss caterpillar.

Gaston was reaching into the back of her car parked outside of her home when she felt an excruciating pain.

‘It felt exactly like a scorching-hot knife passing through the outside of my calf,’ said Gaston, 55, of New Kent County.

‘Before I looked down to see where it came from, I thought 100 percent I was going to see a big piece of metal, super sharp, sticking out from my car.’

She felt ‘white hot pain’ and immediately went to the emergency room – it took her three days to feel normal again.

This post first appeared on dailymail.co.uk

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Denisovan DNA discovered in a Tibetan cave may be only 45,000 years old

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denisovan dna discovered in a tibetan cave may be only 45000 years old

DNA belonging to Denisovans – the ancient human ancestor – discovered in a Tibetan cave may be only 45,000 years old, scientists say. 

The ancient Denisovan mitochondrial DNA was recovered in sediments from Baishiya Karst Cave, a limestone cave at the northeast margin of the Tibetan Plateau, 3,280 meters above sea level. 

Samples indicate Denisovans occupied the high-altitude cave as early as 100,000 years ago, and possibly as recently as 45,000 years ago, as well as at a point in-between. 

If the DNA is indeed only 45,000 years old, the species would have lived alongside modern humans in northeast central Asia. 

Site of Baishiya Karst Cave, a Tibetan Buddhist sanctuary and a high-altitude paleoanthropological site for researchers

Site of Baishiya Karst Cave, a Tibetan Buddhist sanctuary and a high-altitude paleoanthropological site for researchers

Site of Baishiya Karst Cave, a Tibetan Buddhist sanctuary and a high-altitude paleoanthropological site for researchers

Denisovans, a group of extinct hominins that diverged from Neanderthals about 400,000 years ago, may have more widely inhabited northeast central Asia than scientists previously thought.  

Samples of sediments were analysed by an international team including Charles Perreault at Arizona State University.

‘When we started developing this project about 10 years ago, none of us expected Baishya Cave to be such a rich site,’ he said

‘We’ve barely scratched the surface – three small excavation units have yielded hundreds of stone tools, fauna and ancient DNA. There’s a lot that remains to be done.’ 

‘Future work in Baishiya Cave may give us a truly unique access to Denisovan behavior and solidifies the picture that is emerging, which is that Denisovans, like Neanderthals, were not mere offshoots of the human family tree.

‘They were part of a web of now-extinct populations that contributed to the current human gene pool and shaped the evolution of our species in ways that we are only beginning to understand.’

By examining the sediment of Baishiya Karst Cave located on a high plateau in Tibet, researchers identified ancient mitochondrial DNA from Denisovans, indicating their presence possibly 45,000 years ago

By examining the sediment of Baishiya Karst Cave located on a high plateau in Tibet, researchers identified ancient mitochondrial DNA from Denisovans, indicating their presence possibly 45,000 years ago

By examining the sediment of Baishiya Karst Cave located on a high plateau in Tibet, researchers identified ancient mitochondrial DNA from Denisovans, indicating their presence possibly 45,000 years ago

A mandible fossil (the ‘Xiahe mandible’) from the same cave, which was dated to 160,000, had been previously identified as Denisovan, based on a single amino acid position. 

This new study of the DNA dispels any doubt left that the Denisovans occupied the cave, according to the researchers. 

Evidence of archaic hominins this far above sea level is unusual due to the severity of the conditions at high altitude.  

Life on the plateau is harsh due to its thin air, and humans can develop altitude sickness anywhere above 2,500 meters above sea level. 

Presence of the DNA suggests the Denisovans may have evolved adaptations to high altitude, much like modern Tibetans. 

The dates of the sediments with mitochondrial DNA, along with the older 160,000-year-old Xiahe mandible, suggest that the Denisovans have been on the Plateau continuously for tens of thousands of years.

Pictured, the Xiahe mandible remains. The Denisovan jawbone was originally discovered in 1980 by a local monk

Pictured, the Xiahe mandible remains. The Denisovan jawbone was originally discovered in 1980 by a local monk

Pictured, the Xiahe mandible remains. The Denisovan jawbone was originally discovered in 1980 by a local monk

This would have been more than long enough for genetic adaptations to emerge in Denisovans to help them survive adverse effects of high altitude. 

This discovery in Baishiya Karst Cave is the first time Denisovan DNA has been recovered from a location that is outside Denisova Cave in Siberia, Russia. 

This Siberian cave was previously the single location in the world where a handful of DNA-bearing Denisovan fossil bones have been discovered. 

In 2010, a fingerbone belonging to a previously unknown hominin species was found buried in Denisova Cave in the Russian Altai Mountains. 

Evidence of this new species forced anthropologists to revise their model of human evolution outside of Africa. 

Scientists had thought that modern humans left Africa about 60,000 years ago and, as they colonized Western Eurasia, found a world empty of any other archaic hominin species.

But this assumption stemmed in part from the fact that the prehistory of Asia is poorly known compared to that of Africa and Europe. 

Researchers suspected that Denisovans were widespread in Asia, based on the widespread Denisovan genomic signal among present-day Asians. 

The new study has been published in the journal Science.                   

It is thought that the shared ancestors of Denisovans and Neanderthals, which are unknown in the fossil record, likely split from the ancestors of modern humans around 800,000 years ago

It is thought that the shared ancestors of Denisovans and Neanderthals, which are unknown in the fossil record, likely split from the ancestors of modern humans around 800,000 years ago

It is thought that the shared ancestors of Denisovans and Neanderthals, which are unknown in the fossil record, likely split from the ancestors of modern humans around 800,000 years ago

WHO WERE THE DENISOVANS?

The Denisovans are an extinct species of human that appear to have lived in Siberia and even down as far as southeast Asia.

Although remains of these mysterious early humans have only been discovered at one site – the Denisova Cave in the Altai Mountains in Siberia, DNA analysis has shown they were widespread.

DNA from these early humans has been found in the genomes of modern humans over a wide area of Asia, suggesting they once covered a vast range.

DNA analysis of a fragment of pinky finger bone in 2010, (pictured) which belonged to a young girl, revealed the Denisovans were a species related to, but different from, Neanderthals.

DNA analysis of a fragment of pinky finger bone in 2010, (pictured) which belonged to a young girl, revealed the Denisovans were a species related to, but different from, Neanderthals.

DNA analysis of a fragment of pinky finger bone in 2010, (pictured) which belonged to a young girl, revealed the Denisovans were a species related to, but different from, Neanderthals.

They are thought to have been a sister species of the Neanderthals, who lived in western Asia and Europe at around the same time.

The two species appear to have separated from a common ancestor around 200,000 years ago, while they split from the modern human Homo sapien lineage around 600,000 years ago. 

Bone and ivory beads found in the Denisova Cave were discovered in the same sediment layers as the Denisovan fossils, leading to suggestions they had sophisticated tools and jewellery.

DNA analysis of a fragment of a fifth digit finger bone in 2010, which belonged to a young girl, revealed they were a species related to, but different from, Neanderthals.

Later genetic studies suggested that the ancient human species split away from the Neanderthals sometime between 470,000 and 190,000 years ago. 

Anthropologists have since puzzled over whether the cave had been a temporary shelter for a group of these Denisovans or it had formed a more permanent settlement.

DNA from molar teeth belonging to two other individuals, one adult male and one young female, showed they died in the cave at least 65,000 years earlier.

Other tests have suggested the tooth of the young female could be as old as 170,000 years.

A third molar is thought to have belonged to an adult male who died around 7,500 years before the girl whose pinky was discovered.

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Gem seal engraved with a portrait of the Greek god Apollo found in Jerusalem dates back 2,000 years

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gem seal engraved with a portrait of the greek god apollo found in jerusalem dates back 2000 years

A 2,000-year-old tiny gem seal cut of dark brown jasper that depicts the face of the Greek god Apollo has been discovered in Jerusalem‘s Western Wall.

The oval-shaped piece is just 13 mm long and 11 mm wide and was used as a stamp for personal signatures on contracts, letters and other goods – but experts believe it was worn as jewelry.

Although such seals were very common, this one is unique due to it being made of a precious stone in antiquity and bearing an engraving of a god not of the Jewish faith.

The engraving shows a side profile of a face, with long hair flowing down Apollo’s neck, a large nose and thick lips, along with a prominent chin.

Archaeologist say it is rare to find in image of another god in Jerusalem and suggests its owner was ‘making use of the impact that Apollo’s figure represents: light, purity, health and success.’

A 2,000-year-old tiny gem seal cut of dark brown jasper that depicts the face of the Greek god Apollo has been discovered in Jerusalem's Western Wall

A 2,000-year-old tiny gem seal cut of dark brown jasper that depicts the face of the Greek god Apollo has been discovered in Jerusalem's Western Wall

A 2,000-year-old tiny gem seal cut of dark brown jasper that depicts the face of the Greek god Apollo has been discovered in Jerusalem’s Western Wall

The gem seal was found during the Tzurim Valley National Park sifting project and researchers say it is only the third of its kind to be found from the Second Temple period, the Jewish News Syndicate reports.

Eli Shukron, who conducted the excavation in which the gem was found, said: ‘To this day, two such gems (seals) have been found in Masada, another in Jerusalem inside an ossuary (burial box) in a Jewish tomb on Mount Scopus, and the current gem that was discovered in close proximity to the Temple Mount.’

The pieces was crafted from the precious jasper stone and has remnants of yellow-light, brown and white layers throughout.

Archaeologists believe the gem seal may have been worn as a ring by someone of the Jewish faith, instead of being used to seal documents.

35010738 0 image a 23 1603993191383

35010738 0 image a 23 1603993191383

The oval-shaped piece is just 13 mm long and 11 mm wide and was used as a stamp for personal signatures on contracts, letters and other goods – but experts believe it was worn as jewelry

‘It is rare to find seal remains bearing the image of the god Apollo at sites identified with the Jewish population,’ said Shukron.

‘When we found the gem, we asked ourselves ‘what is Apollo doing in Jerusalem? And why would a Jew wear a ring with the portrait of a foreign god?’

‘The answer to this, in our opinion, lies in the fact that the owner of the ring wore it not as a ritual act that expresses religious belief, but as a means of making use of the impact that Apollo’s figure represents: light, purity, health, and success.’

Researchers note that Apollo, which is associate with divination, was one of the most revered gods of the time in Eastern Mediterranean regions.

The engraving shows a side profile of a face, with long hair flowing down Apollo's neck, a large nose and thick lips, along with a prominent chin

The engraving shows a side profile of a face, with long hair flowing down Apollo's neck, a large nose and thick lips, along with a prominent chin

The engraving shows a side profile of a face, with long hair flowing down Apollo’s neck, a large nose and thick lips, along with a prominent chin

Archaeologists believe the gem seal may have been worn as a ring by someone of the Jewish faith, instead of being used to seal documents

Archaeologists believe the gem seal may have been worn as a ring by someone of the Jewish faith, instead of being used to seal documents

Archaeologists believe the gem seal may have been worn as a ring by someone of the Jewish faith, instead of being used to seal documents

Shua Amorai-Stark, an expert on engraved gems, told the Jewish News Syndicate: ‘Among Apollo’s spheres of responsibility, it is likely that association with sun and light (as well as with logic, reason, prophecy and healing) fascinated some Jews, given that the element of light versus darkness was prominently present in Jewish worldview in those days.’

He also noted that the specific colors were not chosen by accident, but were likely used to highlight ‘the aspect of light in the god’s persona.’

Apollo is said to have been the most loved of all the Greek gods and stories say he was the son of Zeus and twin brother of Artemis.

The pieces was crafted from the precious jasper stone and has remnants of yellow-light, brown and white layers throughout

The pieces was crafted from the precious jasper stone and has remnants of yellow-light, brown and white layers throughout

The pieces was crafted from the precious jasper stone and has remnants of yellow-light, brown and white layers throughout

He is known for play a role in Homer’s account of the Trojan War in the Illiad.

Apollo took the side of the Trojans and assisted the famous soldiers Hector, Aeneas and Glaukos – all of which he used divine intervention to save their lives on numerous occasions.

He also sent a plague to destroy the Trojans’ enemies – the Achaeans.

Homer describes this god as the ‘far-shooter’, rouser of armies’, and ‘Phoebus Apollos’.

This post first appeared on dailymail.co.uk

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