An Overview of Common Infrared Techniques for Detecting CO Intermediates on Metal Surfaces for Hydrocarbon Products

Detection of intermediates during the catalytic process by infrared techniques has been widely implemented for many important reactions. For the reduction of CO2 into hydrocarbons on metal surfaces, CO molecule is one of the most important transient species to be followed due to its involvement in several products’ pathways, and its distinct vibrational features. Herein, basic understandings behind these utilized infrared techniques are illustrated aiming for highlighting the potential of each infrared technique and its advantages over the other ones for detecting CO molecules on metal surfaces.

Advances in Diffraction Studies of Light-Induced Transient Species in Molecular Crystals and Selected Complementary Techniques

The review provides a summary of the current methods of tracing photoexcitation processes and structural dynamics in the solid state, putting major emphasis on the X-ray diffraction techniques (time-resolved Laue diffraction on synchrotron sources and time-resolved serial femtosecond crystallography on X-ray free-electron lasers). The recent developments and nowadays experimental possibilities in the field are discussed along with the data processing and analysis approaches, and illustrated with some striking literature examples of the respective successful studies. Selected complementary methods, such as ultrafast electron diffraction or time-resolved X-ray absorption spectroscopy, are briefly presented.

Identification of insects associated with ebony (Diospyros celebica Bakh.) as an endemic tree to Sulawesi

The population of ebony trees in Sulawesi has decreased and has been included in Appendix II Cites, which means it can only be traded based on quotas. Insect studies on ebony stands are still limited, especially in South Sulawesi. This study aims to determine the diversity and association of ebony with insects found in ebony stands in the Hasanuddin University Education Forest, Maros Regency. This activity was carried out in June 2021. Sampling was carried out using the light trap method for winged insects with nocturnal activity and pitfall traps for insects crawling on the ground. Data analysis to determine the diversity of insect species was carried out using the Shannon-Wiener (H') species and the Margalef index. The results showed that the insects found were 8 orders, 20 families, and 28 species from 128 individuals. Based on analysis of their functional role, the insect complexes consist of 34% herbivores, 50% predators, 8% parasitoids, 14% detritivores and 2% transient species. The diversity of species was classified as moderate, namely 2.71, while the richness index value of 5.56, which was classified as high richness in Ebony Stands.

The effect of removing dental plaque with low-frequency ultrasound and ozonized contact medium on the microbiota of the gingival sulcus with diagnosis chronic catarrhal gingivitis of young age patients

As a result of the study, it was found that the removal of dental plaque using low-frequency ultrasound and ozonized contact medium in chronic generalized catarrhal gingivitis of young people can significantly improve the state of microbiocenosis of the gingival sulcus. The preservation of the main resident species is noted, occasional transient species disappear and the frequency of isolation of aggressive representatives of beta-hemolytic streptococci and periodontopathogenic species decreases. When using ozonated water for the removal of dental deposits, the efficiency of eradication of the microbiota of the gingival sulcus, especially of representatives of aggressive species, is higher than when removing dental deposits without the use of ozonated water.

Message in a Bottle, Metabarcoding Enables Biodiversity Comparisons Across Ecoregions

Background Traditional biomonitoring approaches have delivered a basic understanding of biodiversity, but they cannot support the large scale assessments required to manage and protect entire ecosystems. This study employed DNA metabarcoding to assess spatial and temporal variation in species richness and diversity in arthropod communities from 52 protected areas spanning three Canadian ecoregions. Results This study revealed the presence of 26,263 arthropod species in the three ecoregions and indicated that at least another 3,000 to 5,000 await detection. Results further demonstrate that communities are more similar within than between ecoregions, even after controlling for geographical distance. Overall alphadiversity declined from east to west, reflecting a gradient in habitat disturbance. Shifts in species composition were high at every site with turnover greater than nestedness, suggesting the presence of many transient species. Conclusions Differences in species composition among their arthropod communities confirm that ecoregions are a useful synoptic for biogeographic patterns and for structuring conservation efforts. The present results also demonstrate that metabarcoding enables large scale monitoring of shifts in species composition, making it possible to move beyond the biomass measurements that have been the key metric employed in prior efforts to track change in arthropod communities.

Radiation- and Photo-Induced Oxidation Pathways of Methionine in Model Peptide Backbone under Anoxic Conditions

Within the reactive oxygen species (ROS) generated by cellular metabolisms, hydroxyl radicals (HO•) play an important role, being the most aggressive towards biomolecules. The reactions of HO• with methionine residues (Met) in peptides and proteins have been intensively studied, but some fundamental aspects remain unsolved. In the present study we examined the biomimetic model made of Ac-Met-OMe, as the simplest model peptide backbone, and of HO• generated by ionizing radiation in aqueous solutions under anoxic conditions. We performed the identification and quantification of transient species by pulse radiolysis and of final products by LC-MS and high-resolution MS/MS after γ-radiolysis. By parallel photochemical experiments, using 3-carboxybenzophenone (CB) triplet with the model peptide, we compared the outcomes in terms of short-lived intermediates and stable product identification. The result is a detailed mechanistic scheme of Met oxidation by HO•, and by CB triplets allowed for assigning transient species to the pathways of products formation.

A tandem activity-based sensing and labeling strategy enables imaging of transcellular hydrogen peroxide signaling

Reactive oxygen species (ROS) like hydrogen peroxide (H2O2) are transient species that have broad actions in signaling and stress, but spatioanatomical understanding of their biology remains insufficient. Here, we report a tandem activity-based sensing and labeling strategy for H2O2 imaging that enables capture and permanent recording of localized H2O2 fluxes. Peroxy Green-1 Fluoromethyl (PG1-FM) is a diffusible small-molecule probe that senses H2O2 by a boronate oxidation reaction to trigger dual release and covalent labeling of a fluorescent product, thus preserving spatial information on local H2O2 changes. This unique reagent enables visualization of transcellular redox signaling in a microglia–neuron coculture cell model, where selective activation of microglia for ROS production increases H2O2 in nearby neurons. In addition to identifying ROS-mediated cell-to-cell communication, this work provides a starting point for the design of chemical probes that can achieve high spatial fidelity by combining activity-based sensing and labeling strategies.

CF3-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

“The extraordinary instability of such an “ion” accounts for many of the peculiarities of organic reactions” – Franck C. Whitmore (1932). This statement from Whitmore came in a period where carbocations began to be considered as intermediates in reactions. Ninety years later, pointing at the strong knowledge acquired from the contributions of famous organic chemists, carbocations are very well known reaction intermediates. Among them, destabilized carbocations – carbocations substituted with electron-withdrawing groups – are, however, still predestined to be transient species and sometimes considered as exotic ones. Among them, the CF3-substituted carbocations, frequently suggested to be involved in synthetic transformations but rarely considered as affordable intermediates for synthetic purposes, have long been investigated. This review highlights recent and past reports focusing on their study and potential in modern synthetic transformations.

How volatile components catalyze vapor nucleation

Gas phase nucleation is a ubiquitous phenomenon in planetary atmospheres and technical processes, yet our understanding of it is far from complete. In particular, the enhancement of nucleation by the addition of a more volatile, weakly interacting gaseous species to a nucleating vapor has escaped molecular-level experimental investigation. Here, we use a specially designed experiment to directly measure the chemical composition and the concentration of nucleating clusters in various binary CO2-containing vapors. Our analysis suggests that CO2 essentially catalyzes nucleation of the low vapor pressure component through the formation of transient, hetero-molecular clusters and thus provides alternative pathways for nucleation to proceed more efficiently. This work opens up new avenues for the quantitative assessment of nucleation mechanisms involving transient species in multicomponent vapors.