A third of American corporate debt is rated BBB, the lowest investment-grade rating.

三分之一的美国公司债务评级 BBB，这最低的投资级评级。

And the ratings that were awarded to the bank—of a3 and bbb respectively—were far from the highest notches available.

该银行获得的评级（分 a3 bbb）远低于现​​有的最高评级。

That has been good news for the high-yield, or junk, bond market, where companies with poor credit ratings (below the investment-grade threshold of BBB) turn for finance.

这于高收益债券市场或者垃圾债券市场来，消息.在那里，低信用评级的企业，也就低于投资评级BBB级门槛的企业，可以寻求融资机遇.

CSF analysis can also show an elevated protein concentration because the inflammation leads to a more permeable blood brain barrier, or BBB, which is a selective semipermeable barrier between the circulating blood and the central nervous system.

脑脊液检查也可有蛋白含量升高，由于炎症导致介于循环血流中枢神经系统之间的半透膜屏障，即血脑屏障，通透性升高。

At the same time, debt issuance has slowed and yields on American corporate bonds rated bbb, the lowest and most common investment-grade rating, have risen to 5.1%, up from an average of 2.4% in 2021.

与此同时，债务发行放缓，评级 bbb 的美国公司债券收益率已从 2021 年的平均 2. 4% 上升至 5. 1%。