Recent advances in vegetable oil-based polymers and their composites

Apoptosis causes elimination of more than 99% of germ cells from cohort of ovary through follicular atresia. Less than 1% of germ cells, which are culminated in oocytes further undergo apoptosis during last phases of oogenesis and depletes ovarian reserve in most of the mammalian species including human. There are several players that induce apoptosis directly or indirectly in oocytes at various stages of meiotic cell cycle. Premature removal of encircling granulosa cells from immature oocytes, reduced levels of adenosine 3',5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate, increased levels of calcium (Ca(2+)) and oxidants, sustained reduced level of maturation promoting factor, depletion of survival factors, nutrients and cell cycle proteins, reduced meiotic competency, increased levels of proapoptotic as well as apoptotic factors lead to oocyte apoptosis. The BH3-only proteins also act as key regulators of apoptosis in oocyte within the ovary. Both intrinsic (mitochondria-mediated) as well as extrinsic (cell surface death receptor-mediated) pathways are involved in oocyte apoptosis. BID, a BH3-only protein act as a bridge between both apoptotic pathways and its cleavage activates cell death machinery of both the pathways inside the follicular microenvironment. Oocyte apoptosis leads to the depletion of ovarian reserve that directly affects reproductive outcome of various mammals including human. In this review article, we highlight some of the important players and describe the pathways involved during oocyte apoptosis in mammals.

Apoptosis in mammalian oocytes: a review.

Artificial oocyte activation and intracytoplasmic sperm injection

Photocatalytic transformation fate and toxicity of ciprofloxacin related to dissociation species: Experimental and theoretical evidences

The photodegradation of polybrominated diphenyl ethers (PBDEs) in various environmental matrices: Kinetics and mechanisms

Theoretical insight into the degradation of p-nitrophenol by OH radicals synergized with other active oxidants in aqueous solution.

2,4,4'-Tribromodiphenyl ether (BDE-28) was selected as a typical congener of polybrominated diphenyl ethers (PBDEs) to examine its fate both in the atmosphere and in water solution. All the calculations were obtained at the ground state. The mechanism result shows that the oxidations between BDE-28 and OH radicals are highly feasible especially at the less-brominated phenyl ring. Hydroxylated dibrominated diphenyl ethers (OH-PBDEs) are formed through direct bromine-substitution reactions (P1 similar to P3) or secondary reactions of OH-adducts (P4 similar to P8). Polybrominated dibenzo-p-dioxins (PBDDs) resulting from o-OH-PBDEs are favored products compared with polybrominated dibenzofurans (PBDFs) generated by bromophenols and their radicals. The complete degradation of OH adducts in the presence of O-2/NO, which generates unsaturated ketones and aldehydes, is less feasible compared with the H-abstraction pathways by O. Aqueous solution reduces the feasibility between BDE-28 and the OH radical. The rate constant of BDE-28 and the OH radical is determined to be 1.79 X 10(-12) cm(3) molecule(-1) s(-1) with an atmospheric lifetime of 6.7 days.

OH-initiated oxidation mechanisms and kinetics of 2,4,4'-Tribrominated diphenyl ether.

This study investigates the decomposition of 2,2′,4,4′,5-pentabrominated diphenyl ether (BDE99), a commonly detected pollutant in the environment. Debromination channels yielding tetrabrominated diphenyl ethers and hydrogen abstracting aromatic bromine atom formations play significant roles in the reaction of BDE99 + H, in which the former absolutely predominates bimolecular reactions. Polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated dibenzofurans (PBDFs) can be produced during BDE99 pyrolysis, especially for PBDFs under inert conditions. The expected dominant pathways in a closed system are debromination products and PBDF formations. The bimolecular reaction with hydroxyl radical mainly leads to hydroxylated BDE99s rather than hydroxylated tetrabrominated diphenyl ethers. PBDDs are then generated from ortho-hydroxylated PBDEs. HO2 radical reactions rarely proceed. The total rate constants for the BDE99 reaction with hydrogen atoms and hydroxyl radicals exhibit positive dependence on temperatur...

Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2',4,4',5-Pentabromodiphenyl Ether.

https://www.fertstert.org/article/S0015-0282(04)01452-9/pdf

Effect of activation with calcium ionophore A23187 and puromycin on human oocytes that failed to fertilize after intracytoplasmic sperm injection

The Cl-initiated oxidation reactions of methyl vinyl ether (MVE) are analyzed by using the high-level composite method CBS-QB3. Detailed chemistry for the reactions of MVE with chlorine atoms is proposed according to the calculated thermodynamic data. The primary eight channels, including two Cl-addition reactions and six H-abstraction reactions, are discussed. In accordance with the further investigation of the two dominant additional routes, formyl chloride and formaldehyde are the major products. Over the temperature range of 200-400 K and the pressure range of 100-2000 Torr, the rate constants of primary reactions are calculated by employing the MESMER program. H-abstraction channels are negligible according to the value of rate constants. During the studied temperature range, the Arrhenius equation is obtained as ktot = 5.64 × 10(-11) exp(215.1/T). The total rate coefficient is ktot = 1.25 × 10(-10) cm(3) molecule(-1) s(-1) at 298 K and 760 Torr. Finally, the atmospheric lifetime of MVE with respect to Cl is estimated to be 2.23 h.

Mingyue Li

Papers

Theoretical insight into the degradation of p-nitrophenol by OH radicals synergized with other active oxidants in aqueous solution.

OH-initiated oxidation mechanisms and kinetics of 2,4,4'-Tribrominated diphenyl ether.

Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2',4,4',5-Pentabromodiphenyl Ether.

Effect of activation with calcium ionophore A23187 and puromycin on human oocytes that failed to fertilize after intracytoplasmic sperm injection

Computational study on the mechanisms and rate constants of the Cl-initiated oxidation of methyl vinyl ether in the atmosphere.