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Let R be a commutative ring, m>1 an integer and q>1 an odd number. The following questions are addressed: (1) when is every element in M n (R) and, respectively, in T n (R) a product of q-potents? (2) when is every element in M n (R) and, respectively, in T n (R) a product of mq-potents? and (3) when is every element in M n (R) and, respectively, in T n (R) a product of an idempotent and a q-potent? [ABSTRACT FROM AUTHOR]

Phenolic compounds have caused different degrees of negative impacts in aquatic environment. Amino acids, humic acids and carbohydrates are the three dominant types of dissolved natural organic matter (DNOM) in natural water bodies. In this research, the influences of dissolved natural organic matter (DNOM) on the adsorption behaviors of phenol, 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) in Weihe River suspended sediment were studied by using DL-alanine, fulvic acid and glucose as the representatives of the three types of DNOM. The results of batch adsorption experiments showed that, without DNOM, Langmuir and Freundlich had good fitting effects on the three phenolic compounds and their maximum adsorption capacities were 21.580, 27.768 and 24.758 mg/kg respectively. The presence of amino acids increased adsorption capacities of the phenol and TCP on suspended sediments by approximately 13.84% and 11.56% respectively. The existence of fulvic acid and glucose positively affected the adsorption of phenol, DCP and TCP on suspended sediment. The isothermal adsorption in the coexistence of different DNOM were more consistent with the nonlinear adsorption. Other influence factors including pH, ionic strength and temperature can influence the adsorption behavior to different extents. The impact of dissolved natural organic matter (DNOM) on adsorption should be fully considered when mastering environmental migration and transformation behaviors of phenolic compounds in water-sediments environment. [ABSTRACT FROM AUTHOR]

The early stage of diabetic nephropathy (DN) is linked to proteinuria. Transforming growth factor (TGF)-[beta]1 increases glomerular permeability to albumin ([P.sub.alb]), whereas 20-HETE and EETs reduce [P.sub.alb]. To investigate the impact of hyperglycemia and hyperlipidemia on 20-HETE, EETs, and TGF-[beta]1 in the glomeruli, rats were divided into four groups: ND rats were fed a normal diet, HF rats were fed a high-fat diet, STZ rats were treated with 35 mg/kg of streptozotocin, and HF/STZ rats were fed a HF diet and treated with STZ. After 10 wk on these regimens, blood glucose, urinary albumin, serum cholesterol, serum triglyceride levels, and the kidney-to-body weight ratio were significantly elevated in STZ and HF/STZ rats compared with HF and ND rats. STZ and HF/STZ rats had histopathologic changes and abnormal renal hemodynamics. Expression of glomerular CYP4A, enzymes for 20-HETE production, was significantly decreased in STZ rats, whereas expression of glomerular CYP2C and CYP2J, enzymes for EETs production, was significantly decreased in both STZ and HF/STZ rats. Moreover, glomerular TGF-[beta]1 levels were significantly greater in STZ and HF/STZ rats than in HF and ND rats. Five-week treatment of STZ rats with clofibrate induced glomerular CYP4A expression and 20-HETE production, but reduced glomerular TGF-[beta]1 and urinary protein excretion. These results demonstrate that hyperglycemia increases TGF-[beta]1 but decreases 20-HETE and EETs production in the glomeruli, changes that may be important in causing glomerular damage in the early stage of DN. CYP-derived eicosanoids; streptozotocin; kidney

We previously reported that inhibition of nitric oxide (NO) synthesis by N-nitro-L-arginine methyl ester (L-NAME) during late pregnancy leads to increased production of renal vascular 20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P-450 (CYP) 4A-derived vasoconstrictor, in pregnant rats. However, the effect of upregulation of vascular 20-HETE production on renal function after NO inhibition is not known. To test the hypothesis that increased gestational vascular 20-HETE synthesis after NO inhibition is involved in mediating blood pressure and renal functional changes, we first determined the I[C.sub.50] value of the effect of nitroprusside (SNP), a NO donor, on renal 20-HETE production in cortical microsomes. We then divided pregnant rats and age-matched virgin rats into a vehicle control group, an L-NAME treatment group (0.25 mg/ml in drinking water), and a group treated with L-NAME plus N-methylsulfonyl- 12,12-dibromododec-11-enamide (DDMS; CYP4A-selective inhibitor, l0 mg x [kg.sup.-1] x [day.sup.-1] iv). After 4 days of treatment, we measured blood pressure, renal blood flow (RBF), renal vascular resistance (RVR), and glomerular filtration rate (GFR) in each group. The addition of SNP (I[C.sub.50] = 22 [micro]M) decreased renal cortical 20-HETE production. In pregnant rats, L-NAME treatment led to significantly higher mean arterial pressure (MAP) and RVR, and lower RBF and GFR. Combined treatment with DDMS and L-NAME significantly attenuated the increases in MAP and RVR and the decrease in GFR, but not the reduction in RBF induced by L-NAME treatment. L-NAME and L-NAME plus DDMS had no significant impact on renal hemodynamics in virgin rats. In addition, chronic treatment with DDMS selectively inhibited cortical 20-HETE production without a significant effect on CYP4A expression in L-NAME-treated pregnant rats. In conclusion, NO effectively inhibits renal cortical microsomal 20-HETE production in female rats. In pregnant rats, the augmentation of renal 20-HETE production after NO inhibition is associated with increased MAP and RVR, whereas decreased GFR is negated by treatment of a selective and competitive CYP4A inhibitor. These results demonstrate that the interaction between renal 20-HETE and NO is important in the regulation of renal function and blood pressure in pregnant rats. pregnancy; cytochrome P-450; arachidonic acid; eicosanoid; kidney; nitric oxide; hypertension

Epoxyeicosatrienoic acids (EETs), which belong to cytochrome P-450 (CYP)-derived eicosanoids, have been implicated to vasodilate renal arterioles, inhibit sodium transport in the nephron, and regulate blood pressure in several animal models. Because pregnancy is associated with changes of blood pressure, the aim of this study was to examine whether renal EET synthesis is altered and whether EETs are involved in blood pressure regulation during pregnancy in rats. Renal microsomal epoxygenase activity increased by 47, 97, and 63% on days 6, 12, and 19 of gestation, respectively. The elevation of epoxygenase activity during pregnancy was associated with an increase in CYP2C11, CYP2C23, and CYP2J2 protein expression on days 6, 12, and 19 of gestation. Moreover, immunohistochemical analysis showed that renal tubular CYP2C11, CYP2C23, and CYP2J2 expression was significantly increased in pregnant rats on days 6, 12, and 19 of gestation. Administration of 6-(2-propargyloxyphenyl)hexanoic acid (PPOH), a selective epoxygenase inhibitor, caused a dose-dependent inhibition of microsomal expoxygenase activity without a significant effect on [omega]-hydroxylase activity in female rats. Interestingly, administration of PPOH (20 mg x [kg.sup.-1] x [day.sup.-1] for 4 days starting on day 15 of pregnancy) increased blood pressure by 21 mmHg and caused a significant decrease in the body weight of fetal pups (1.3 [+ or -] 0.08 g in control vs. 1.1 [+ or -] 0.06 g in PPOH). Moreover, PPOH treatment significantly decreased renal microsomal epoxygenase activity and the expression of CYP2C11, CYP2C23, and CYP2J in pregnant rats. This study demonstrates that EET synthesis in the kidney is elevated during pregnancy, and CYP2C11, 2C23, and CYP2J2 are responsible for the change of renal EET synthesis. The inhibition results demonstrate that the downregulation of renal epoxygenase activity by PPOH causes hypertension in pregnant rats. This study suggests that EETs may contribute to the control of blood pressure during pregnancy. blood pressure; cytochrome P-450; epoxyeicosatrienoic acids

A unit-picker is a map that associates to every ring R a well-defined set (R) of central units in R which contains 1 R and is invariant under isomorphisms of rings and closed under taking inverses, and which satisfies certain set containment conditions for quotient rings, corner rings and matrix rings. Let be a unit-picker. A ring R is called (strongly) nil -clean if for each a ∈ R , a = v e + b where v ∈ (R) , e 2 = e ∈ R and b ∈ R is nilpotent (and a b = b a). An extensive study of (strongly) nil -clean rings is conducted. When is specified, known results of the much-studied (strongly) nil-clean rings and weakly nil-clean rings are re-proved and new results of other nil-clean-like rings are obtained. [ABSTRACT FROM AUTHOR]

As introduced by Cǎlugǎreanu and Lam in [G. Cǎlugǎreanu and T. Y. Lam, Fine rings: a new class of simple rings, J. Algebra Appl.15(9) (2016) 1650173, 18 pp.], a fine ring is a ring whose every nonzero element is the sum of a unit and a nilpotent. As a natural generalization of fine rings, a ring is called a generalized fine ring if every element not in the Jacobson radical is the sum of a unit and a nilpotent. Here some known results on fine rings are extended to generalized fine rings. A notable result states that matrix rings over generalized fine rings are generalized fine, extending the important result in [G. Cǎlugǎreanu and T. Y. Lam, Fine rings: a new class of simple rings, J. Algebra Appl.15(9) (2016) 1650173, 18 pp.] that matrix rings over fine rings are fine. [ABSTRACT FROM AUTHOR]