Please see for reference the IRS publication 901 - http://www.irs.gov/pub/irs-pdf/p901.pdf
According to US-Russia tax treaty - Income that residents of Russia receive for employment in the United States (dependent personal services) is exempt from U.S. income tax if the following three requirements are met.
As Dr. Boyko is on the J-1 visa - he is considered a non-resident of the US, but because the employer is a resident of US that exemption doesn't apply.
Pay of professors and teachers who are residents of Russia is not exempt from U.S. income tax.
However Scholarship or fellowship grant paid by any U.S. or foreign resident to the resident of Russia is not taxable income within 5 years. -- Treaty Article Citation -18 -- please see the table entry on the page 45.
Thus - Dr. Boyko is correct.