Mechanisms of 1s Double-Core-Hole Excitation and Decay in Neon

The formation and decay of double-core-hole (DCH) states of the neon ion irradiated by an intense electromagnetic x-ray field are studied theoretically. In the present research DCH formation is the result of sequential absorption of two photons with the creation of an intermediate ion. Detailed calculations of the partial decays and probabilities of shake-ups at the atomic and ionic ionization stages are presented. The angular distribution of photoelectrons corresponding to various residual ionic states are calculated. Specifically, we predict the lack of any photoelectrons corresponding to the residual ionic state 1s12s22pnmpn′2Sf+1D in the direction of the electric field polarization. Dynamical competition between single-core-hole state decay and excitation is analyzed and pulse parameters corresponding to various dynamical regimes are found.

Mechanistic insights into two-photon-driven photocatalysis in organic synthesis

Is two-photon catalysis better than one-photon? The sequential absorption of two photons enables the production of highly reducing or oxidizing species. The short lifetime of the excited states and the photostability of the photocatalyst pose significant limitations to this approach.

Co-morditities of environmental diseases: A common cause

ABSTRACT The global pandemic of non-vector borne environmental diseases may, in large part, be attributed to chronic exposures to ever increasing levels of exogenous lipophilic chemicals. These chemicals include persistent organic pollutants, semi-volatile compounds and low molecular weight hydrocarbons. Such chemicals facilitate the sequential absorption of otherwise not absorbed more toxic hydrophilic species that attack numerous body organs and systems, leading to environmental disease. Co-morbidities of noncommunicable environmental diseases are alarmingly high, with as many as half of all individuals chronically ill with two or more diseases. Co-morbidity is to be anticipated, since all of the causative chemicals identified have independently been shown to trigger the individual diseases.

Exposure to lipophilic chemicals as a cause of neurological impairments, neurodevelopmental disorders and neurodegenerative diseases

ABSTRACT Many studies have associated environmental exposure to chemicals with neurological impairments (NIs) including neuropathies, cognitive, motor and sensory impairments; neurodevelopmental disorders (NDDs) including autism and attention deficit hyperactivity disorder (ADHD); neurodegenerative diseases (NDGs) including Alzheimer´s disease, Parkinson’s disease and amyotrophic lateral sclerosis (ALS). The environmental chemicals shown to induce all these diseases include persistent organic pollutants (POPs), the plastic exudates bisphenol A and phthalates, low molecular weight hydrocarbons (LMWHCs) and polynuclear aromatic hydrocarbons (PAHs). It is reported here that though these chemicals differ widely in their chemical properties, reactivities and known points of attack in humans, a common link does exist between them. All are lipophilic species found in serum and they promote the sequential absorption of otherwise non-absorbed toxic hydrophilic species causing these diseases.

Predicting co-morbidities in chemically sensitive individuals from exhaled breath analysis

ABSTRACT The exhaled breath of more than four hundred patients who presented at the Environmental Health Center - Dallas with chemical sensitivity conditions were analyzed for the relative abundance of their breath chemical composition by gas chromatography and mass spectrometry for volatile and semi-volatile organic compounds. All presenting patients had no fewer than four and as many as eight co-morbid conditions. Surprisingly, almost all the exhaled breath analyses showed the presence of a preponderance of lipophilic aliphatic and aromatic hydrocarbons. The hydrophilic compounds present were almost entirely of natural origin, i.e. expected metabolites of foods. The lipophile, primarily C3 to C16 hydrocarbons and believed to have come from inhalation of polluted air, were, in all cases, present at concentrations far below those known to be toxic to humans, but caused sensitivity and signs of chemical overload. The co-morbid health effects observed are believed to be caused by the sequential absorption of lipophilic and hydrophilic chemicals; an initial absorption and retention of lipophile followed by a subsequent absorption of hydrophilic species facilitated by the retained lipophile to produce chemical mixtures that are toxic at very low levels. It is hypothesized that co-morbid conditions in chemically sensitive individuals can be predicted from analysis of their exhaled breath.