于是，Vineet D. Menachery教授等利用SARS-CoV的反向遗传系统，从中提取并鉴定了一种嵌合病毒，该病毒在适应小白鼠的SARS-CoV主干中可表达出蝙蝠冠状病毒SHC014的刺突。结果表明，该新型冠状病毒能利用SARS的人类细胞受体——血管紧张素转换酶II（ACE2）的多个同源基因，在人类呼吸道原代细胞中有效复制，并在体外获得与SARS传染性同等的效果。
如前所述，野生型和嵌合病毒均来自 SARS-CoV Urbani 或相应的小鼠适应性（SARS-CoV MA15）感染性克隆（ic）病毒细胞。通过提取含有 SHC014 刺突序列的质粒，并连接到 MA15 感染性克隆的 E 和 F 质粒中。设计该克隆并从 Bio Basic 购买六种连续 cDNA，并使用侧接独特的 II 类限制性核酸内切酶位点（BglI）的公开序列。
Taiwan formally signed an agreement to buy 66 of the latest model F-16 jets built by Lockheed Martin Corp., a move likely to further inflame tensions between the U.S. and China.
Taiwan’s purchase of the F-16s marks the first sale of advanced fighter jets to the island since President George H.W. Bush announced approval for 150 F-16s in 1992. A $62 billion figure announced by the Pentagon on Friday is the upper limit of numerous contracts if all potential foreign customers placed their maximum desired number over the decade.
The move is likely to be denounced by Beijing, even though the U.S. first signaled its plans to approve the sale a year ago in an informal notification to Congress and it could still be years before the jets are delivered.
The announcement said that work on the 90 jets potentially to be sold under Friday’s announcement would be complete by late 2026.
Company officials have previously said they project a market for as many as 400 of the new F-16s.
U.S. Backs F-16 Sale to Taiwan, Drawing Warning From China
When the planned sale was announced in August last year, a spokeswoman for China’s Foreign Ministry told reporters that “U.S. arms sales to Taiwan severely violate the one-China principle.”
The spokeswoman, Hua Chunying, said at the time that her government was urging the U.S. to “refrain” from selling the “fighter jets to Taiwan and stop arms sales to, and military contact with, Taiwan. Otherwise, the Chinese side will surely make strong reactions, and the U.S. will have to bear all the consequences.”
Since then, ties with the U.S. have only frayed further, with the two nations in a series of disputes ranging from the origins of the Covid-19 pandemic to 5G technology and Beijing’s tightening grip over Hong Kong.
In addition to Taiwan, Morocco is buying 24 F-16s jets in the first tranche of 90 aircraft that the Pentagon said was valued at $4.9 billion. The Pentagon announcement didn’t name Taiwan or Morocco, but they have been identified in a previous statement and were confirmed Friday by a person familiar with the contract.
The new F-16s are being assembled at Lockheed’s new facility in Greenville, South Carolina, which opened in April 2019. The contracting mechanism used by the Pentagon “will facilitate faster contract awards and greater pricing clarity for our foreign military partners,” Brian Brackens, an Air Force spokesman, said in a statement to Bloomberg News before the contract announcement.
“Taiwan and Morocco are expected to be the first two partner nations that will utilize this contract,” Brackens said.
The Taiwan F-16s will be equipped with a top-line fire control radar made by Northrop Grumman Corp. Called the APG-83, it would allow precision-guided munitions to be fired at greater distances, said an official familiar with the details.
Lockheed Chief Financial Officer Kenneth Possenriede told analysts on a July 21 earnings call that the company was anticipating a “quite large” F-16 order “that should get announced sometime this quarter” in which “the marquee customer is Taiwan.”
The additional 90 F-16s would add to Lockheed’s current 38-aircraft backlog.
The city of Chicago invested nearly $120 million on four separate emergency coronavirus facilities in the spring that ended up treating a total of 38 patients, bringing the effective price tag of the massive project to over $3 million per patient.
Municipal officials spent $66 million on the rapid construction of a 2,750-bed makeshift facility in the city's McCormick Place Convention Center in April, as well as an additional $50 million preparing three previously shuttered hospitals in the nearby districts of Elgin, Blue Island and Melrose.
The McCormick Place field hospital was the only one of the four that welcomed any patients, with just under 40 total being placed there — roughly 1.3% of the facility's total occupancy.
The multimillion-dollar projects were an "insurance policy” at a time of "immense emergency," Chicago Mayor Lori Lightfoot's office told the Chicago Sun-Times this week. One of Lightfoot's deputy mayors, Samir Mayekar, told the paper he was "incredibly proud" of the projects, and that the money invested in them was "not spent in vain." He also claimed that the medical equipment mobilized for the facilities "is being stored and can be redeployed if needed," the paper said.
The facilities came together around the time of the height of the pandemic in the U.S. in late April, when daily deaths peaked at around 2,700 per day. At the time, officials across the U.S. were concerned that waves of deaths could overwhelm local hospitals and lead to collapsed healthcare systems, leading many municipalities to construct makeshift emergency facilities in anticipation.
As in Chicago, earlier in the pandemic numerous field hospitals in cities such as Richmond, Va., Seattle and New York saw very little to no patients at all.
