6. INCOME TAXES

Income tax expense from continuing operations for the years ended May 31, 2019 and 2018 consists of the following:

Years ended May 31,	2019		2018
Current:
U.S. Federal	$	--	$	--
Foreign Taxes Subsidiaries		(13,437)		--
State and local		(800)		(800)
Total current		(14,237)		(800)
Deferred:
U.S. Federal		(10,000)		(31,000)
State and local		--		--
Total deferred		(10,000)		(31,000)
Income tax expense	$	(24,237)	$	(31,800)

Income tax benefit (expense) from continuing operations differs from the amounts computed by applying the U.S. Federal income tax rate applicable for each year (21% for 2019 and blended rate for 2018 (35% and 21%)) to pretax income as a result of the following:

Years ended May 31,	2019		2018
Computed "expected" tax benefit	$	497,453	$	418,258
Increase (reduction) in income taxes resulting from:
Change in valuation allowance		(910,000)		(114,000)
State income taxes, net of federal benefit		89,267		71,794
Research and development tax credits		55,908		46,602
Permanent tax differences and other		(256,572)		78,795
Foreign taxes of subsidiaries		(13,437)		--
Impact of tax rate changes		--		(533,249)
Income tax expense	$	(24,237)	$	(31,800)

The tax effect of significant temporary differences is presented below:

As of May 31,	2019		2018
Deferred tax assets:
Accounts receivable, principally due to allowance for doubtful accounts	$	18,000	$	15,000
Inventory valuation		12,000		13,000
Compensated absences		48,000		49,000
Net operating loss carryforwards		1,735,000		923,000
Tax credit carryforwards		467,000		385,000
Deferred rent expense		9,000		5,000
Other		176,000		163,000
Accumulated depreciation and amortization		(6,000)		6,000
Total deferred tax assets		2,459,000		1,559,000
Less valuation allowance		(2,459,000)		(1,549,000)
Net deferred tax asset	$	--	$	10,000

The Company has provided a valuation allowance of approximately $2,459,000 and $1,549,000 as of May 31, 2019 and 2018, respectively. The net change in the valuation allowance for the years ended May 31, 2019 and 2018 was an increase of $900,000 and $114,000, respectively.

At May 31, 2019, the Company has Federal income tax net operating loss carryforwards of approximately $6,956,000. At May 31, 2019, the Company has California state income tax net operating loss carryforwards of approximately $3,934,000.

At May 31, 2019, the Company has Federal research and development tax credit carryforward of approximately $389,000. The Federal credits begin to expire in 2027. The Company also had similar credit carryforwards for state purposes of $78,000 at May 31, 2019.

Pursuant to Internal Revenue Code Sections 382 and 383, annual use of the Company's net operating loss ("NOL") and credit carryforwards may be limited by statute because of a cumulative change in ownership of more than 50%. Pursuant to Sections 382 and 383 of the Code, the annual use of the Company's NOLs and credit carryforwards would be limited if there is a cumulative change of ownership (as that term is defined in Section 382(g) of the Code) of greater than 50% in a three-year period. Management has not performed an analysis to determine if the Company has had a cumulative change in ownership of greater than 50%.

For the year ended May 31, 2019, the Company did an analysis of its ASC 740 position and has not identified any uncertain tax positions as defined under ASC 740. Should such position be identified in the future and should the Company owe interest and penalties as a result of this, these would be recognized as interest expense and other expense, respectively, in the consolidated financial statements. The Company is no longer subject to any significant U.S. federal tax examinations by tax authorities for years before fiscal year 2015.