; and (B) by striking the item relating to the Principal Deputy Under Secretary of Defense for Personnel and Readiness and inserting the following new item: Deputy Under Secretary of Defense for Personnel and Health. . (2) OSD reform Section 5315 of such title is further amended by inserting before the item relating to the Deputy Under Secretary of Defense for Policy, as amended by paragraph (1)(A), the following new items: Deputy Under Secretary of Defense for Research and Engineering. Deputy Under Secretary of Defense for Acquisition and Sustainment. . (g) Clerical amendments (1) Heading amendment The heading of section 137a of such title is amended to read as follows: 137a. Deputy Under Secretaries of Defense . (2) Clerical amendment The table of sections at the beginning of chapter 4 of such title is amended by striking the item relating to section 137a and inserting the following new item: 137a. Deputy Under Secretaries of Defense. . (h) Effective dates (1) In general Except as provided in paragraph (2), the amendments made by this section shall take effect on the date of the enactment of this Act. (2) ATL position amendments The amendments made by subsections (b), (c), and (f)(2) of this section shall take effect on February 1, 2018, immediately after the coming into effect of the amendments made by subsections (a) and (b) of section 901 of the National Defense Authorization Act for Fiscal Year 2017 ( Public Law 114–328 ; 130 Stat. 2339), to which the amendments made by subsections (b), (c), and (f)(2) of this section relate. 910. Reduction of number and elimination of specific designations of Assistant Secretaries of Defense (a) Reduction of authorized number Subsection (a)(1) of section 138 of title 10, United States Code, is amended by striking 14 and inserting 13 . (b) Elimination of certain specific designations Subsection (b) of such section is amended— (1) by striking paragraphs (2), (3), and (5)