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Spectrochimica Acta. Part A, Molecular... Mar 2024Conformational space of methoxyacetone (MA) was studied at the MP2/6-311++G(d,p) and DFT(B3LYP)/6-311++G(d,p) levels of theory. Computations predict MA to adopt four...
Conformational space of methoxyacetone (MA) was studied at the MP2/6-311++G(d,p) and DFT(B3LYP)/6-311++G(d,p) levels of theory. Computations predict MA to adopt four conformations, resulting from internal rotations around the O=C-C-O (Trans, Cis) and C-C-O-C (trans, gauche) dihedral angles. The Tt (Trans-trans) conformer is the most stable. The computed energies of two gauche (Tg and Cg) conformers fall in the 3-8 kJ mol range above Tt and should account for 1/3 of the room-temperature gas-phase equilibrium. The energy of Ct form is 11 kJ mol above Tt, and its expected population is negligible (below 1 %). In our earlier work, MA monomers were isolated in cryogenic argon matrices and characterized by infrared spectroscopy. In the experiment, only the most stable Tt conformer was detected in the sample. Signatures of the other conformers were not detected, either in freshly deposited samples, or in samples subjected to different UV irradiations. We rationalize those observations in terms of computed barriers for intramolecular torsions, indicating occurrence of conformational cooling during deposition. The experimental infrared spectrum of the Tt form is now assigned with the aid of anharmonic DFT computations. Exposure of MA to UV irradiation in the 300-260 nm range led to photolysis, according to the Norrish type II mechanism, resulting in dimer between enol acetone and formaldehyde observed as a cage-confined intermediate photoproduct. The subsequent photolysis resulted in the formation of carbon monoxide as the dominating photoproduct, formed in the Norrish type I photoreaction. Mechanistic interpretation of this photo decarbonylation reaction is presented.
PubMed: 38056186
DOI: 10.1016/j.saa.2023.123651 -
Journal of Current Ophthalmology 2023To review the concept of plateau iris and summarize the recent evidence on its diagnosis and management. (Review)
Review
PURPOSE
To review the concept of plateau iris and summarize the recent evidence on its diagnosis and management.
METHODS
This is a narrative review on the plateau iris. A literature review was conducted in PubMed, Google Scholar, and Scopus databases using keywords: angle-closure glaucoma, glaucoma, nonpupillary block glaucoma, plateau iris, and plateau iris management.
RESULTS
This review defined the current knowledge about plateau iris. First of all, the anatomy and epidemiology were discussed. Then, we outlined the available evidence on the diagnosis of plateau iris and its differential diagnosis. Conclusively, the treatment options were mentioned.
CONCLUSIONS
Plateau iris is a condition in which nonpupillary block mechanisms are responsible for intraocular pressure elevation and angle closure attack when a patent peripheral iridotomy has removed the relative pupillary block. An anteriorly positioned ciliary body causes mechanical obstruction of trabecular meshwork in these patients. It is usually seen in younger patients with angle closure and is diagnosed by gonioscopic examination and imaging modalities such as Ultrasound biomicroscopy. Despite the known mechanism of plateau iris, there is no consensus over treatment. Low-dose pilocarpine and Argon laser peripheral iridoplasty are nonsurgical treatments for these patients, but their effects are short-term. Cataract extraction with/without endocyclophotocoagulation (ECP), endocycloplasty, excisional goniotomy, and transscleral cyclophotocoagulation are alternative treatments. Patients should be examined periodically for further progression or recurrence of plateau iris. In cases of glaucoma unresponsive to conventional medical treatments, surgical treatments such as trabeculectomy and drainage devices should be considered.
PubMed: 37680292
DOI: 10.4103/joco.joco_319_22 -
Oman Journal of Ophthalmology 2023
PubMed: 38059093
DOI: 10.4103/ojo.ojo_240_23 -
Cells Oct 2023Cerebral injury is a leading cause of long-term disability and mortality. Common causes include major cardiovascular events, such as cardiac arrest, ischemic stroke, and... (Review)
Review
Cerebral injury is a leading cause of long-term disability and mortality. Common causes include major cardiovascular events, such as cardiac arrest, ischemic stroke, and subarachnoid hemorrhage, traumatic brain injury, and neurodegenerative as well as neuroinflammatory disorders. Despite improvements in pharmacological and interventional treatment options, due to the brain's limited regeneration potential, survival is often associated with the impairment of crucial functions that lead to occupational inability and enormous economic burden. For decades, researchers have therefore been investigating adjuvant therapeutic options to alleviate neuronal cell death. Although promising in preclinical studies, a huge variety of drugs thought to provide neuroprotective effects failed in clinical trials. However, utilizing medical gases, noble gases, and gaseous molecules as supportive treatment options may offer new perspectives for patients suffering neuronal damage. This review provides an overview of current research, potentials and mechanisms of these substances as a promising therapeutic alternative for the treatment of cerebral injury.
Topics: Humans; Neuroprotection; Noble Gases; Gases; Neuroprotective Agents; Brain Injuries; Neurons
PubMed: 37887324
DOI: 10.3390/cells12202480