reactive oxygen species (ros)plays an important role in sperm motility. the physiological generation at low concentration induces beneficial effects on sperm functions and plays a significant role in sperm metabolism. meanwhile, the excessive generation of reactive oxygen species can overwhelm protective mechanism and triggers changes in lipid and protein layers of sperm plasma membrane, which ...

Two possible reactive sites (the oxo site and the Ru site) for water on a high-valent ruthenium(V) oxo complex were examined. Our results suggest that the reaction on the ruthenium (via a seven coordinate intermediate) has both a lower barrier and a product with a lower free energy than the product of addition at the oxo.

In enzymatic C-H activation by hydrogen tunneling, reduced barrier width is important for efficient hydrogen wave function overlap during catalysis. For native enzymes displaying nonadiabatic tunneling, the dominant reactive hydrogen donor-acceptor distance (DAD) is typically ca. 2.7 Å, considerably shorter than normal van der Waals distances. Without a ground state substrate-bound structure fo...

Carboxypeptidase Y (CPY) inhibitor I from the yeast, consisting of 204 amino acid residues, belongs to the phosphatidylethanolaminebinding protein (PEBP) family. The 2.7 Å crystal structure of the ICPY complex has been solved by molecular replacement [1, 2]. The structure of I consists of a major -type domain and an Nterminal helical segment. I has two CPY-binding sites: the N-terminal inhibito...

BACKGROUND Glatiramer acetate therapy is thought to be effective for multiple sclerosis (MS) by promoting T(H)2 cytokine deviation, possibly in the brain, but the exact mechanism and site of action are incompletely understood. Determining the site of action and effect of glatiramer on cell trafficking is of major importance in designing rational combination therapy clinical trials. OBJECTIVE ...

metals can cause oxidative stress by increasing the formation of reactive oxygen species (ros), which make antioxidants incapable of defiance against growing amounts of free radicals. metal toxicity is related to their oxidative state and reactivity with other compounds. however, several reports about metals have been published in the recent years. mitochondria, as a site of cellular oxygen con...

background: tissue injuries may provoke neuro-hormonal response which in turn may lead to release of inflammatory cytokines. we hypothesize that block of afferent sensory pathways by infiltration of 0.5% bupivacaine in the scalp may decrease neuro-hormonal response in the neurosurgical patient. methods: after obtaining informed consent, forty asa physical statuses i, ii, or iii patients between...

Photocatalysis is a method of choice for the generation reactive intermediates under mild conditions. This Review collects recent examples exploiting this manifold to generate highly aggressive halogen radicals activate C(sp3)?H bonds via Hydrogen Atom Transfer (HAT) synthetic purposes. Available strategies influence site-selectivity hydrogen atom transfer step have also been discussed.