Scientific expedition to Tajikistan. Three large-format photos.

Most likely, these photographs were taken by Yevgeny Pavlovsky (1884-1965), a prominent zoologist, entomologist, and academician of the Academy of Sciences of the USSR (1939). He is renowned for orchestrating numerous expeditions to Central Asia, the Transcaucasus, Crimea, and the Russian Far East, all with the purpose of studying endemic parasitic and transmissible diseases. Notably, in 1928, he journeyed to Tajikistan to combat local outbreaks of smallpox, tuberculosis, malaria, typhoid, and other infectious diseases.
The photographs capture the lives of local people. Of particular interest is the image showing a man on a specialized bed designed to protect against fleas as part of efforts against typhoid.
In 1929, Pavlovsky published a book titled "Animal Parasites and Certain Human Parasitic Diseases in Tajikistan", in which one of these photos was included (along with another from a different angle).
In 1932, at the behest of the scientist, the foundation of the Academy of Sciences of the USSR was established in Tajikistan, with his active involvement in its organization and operations. Pavlovsky assumed leadership of the Tajik base for an extended period, subsequently leading the Tajik branch of the USSR Academy of Sciences.
It's plausible that the owner's marks were added later, as they contain the names of geographical locations that emerged after the dates of the photographs (for instance, Sarai-Kamar, also known as Kirowabad, a name it acquired in 1936).