'DeltaCAN - A new data set of Canadian Arctic and subarctic coastal deltas'.

Arctic coasts constitute the critical interface between land and sea, and are subject to rapid changes caused by a warming climate. Current trends throughout the Arctic show increasing erosion trends, while other parts of the coast are experiencing prograding trends. Until now, a vast majority of our knowledge of Arctic coastal evolution is confined to site-specific studies with limited geospatial representation.

[Pseudoaneurysm of the mitro-aortic trigone: Clinical case and literature review].

Case Report: We report the case of a 63-year-old patient who underwent aortic valve replacement with a biological valve for a bicuspid aortic stenosis, and LIMA-IVA single-bypass surgery. Two weeks later, he presented with Enterococcus faecillis bacteremia, attributed to left pyelonephritis and successfully treated with Amoxicillin. Two months after his surgery, he had a new bacteremia due to Enterococcus faecalis and we discovered a pseudo-aneurysm of the mitro-aortic trigone.

Epicardial Fat Volume Assessed by MRI in Adolescents: Associations with Obesity and Cardiovascular Risk Factors.

: In adults, epicardial adipose tissue (EAT) is associated with metabolic syndrome (MS) and coronary artery disease. EAT thickness is increased in obese youth, but total EAT volume and its correlation with cardiovascular risk factors have not been studied. : To determine EAT volume in adolescents and its association with obesity and cardiovascular risk factors.

Zweifel olefination for C-glycosylation.

C-glycosides are significant in medicinal chemistry due to their resistance to enzymatic hydrolysis, making them more stable and bioavailable compared to O-glycosides. Their unique structure also offers potential for developing drugs with improved therapeutic properties, particularly in treating diseases like diabetes and cancer. The main challenge in synthesizing C-glycosides lies in forming the carbon-carbon bond between the sugar and aglycone efficiently, while controlling the stereochemistry and minimizing side reactions.

Stereoselective polar radical crossover for the functionalization of strained-ring systems.

Radical-polar crossover of organoborates is a poweful tool that enables the creation of two C-C bonds simultaneously. Small ring systems have become essential motifs in drug discovery and medicinal chemistry. However, step-economic methods for their selective functionalization remains scarce.

Strain-release arylations for the bis-functionalization of azetidines.

The addition of nucleophilic organometallic species onto generated azabicyclobutanes enables the selective formation of 3-arylated azetidine intermediates through strain-release. Single pot strategies were further developed for the -arylation of resulting azetidines, employing either SAr reactions or Buchwald-Hartwig couplings.

Europe-Wide Atmospheric Radionuclide Dispersion by Unprecedented Wildfires in the Chernobyl Exclusion Zone, April 2020.

From early April 2020, wildfires raged in the highly contaminated areas around the Chernobyl nuclear power plant (CNPP), Ukraine. For about 4 weeks, the fires spread around and into the Chernobyl exclusion zone (CEZ) and came within a few kilometers of both the CNPP and radioactive waste storage facilities. Wildfires occurred on several occasions throughout the month of April.

Electro-alkynylation: Intramolecular Rearrangement of Trialkynylorganoborates for Chemoselective C(sp)-C(sp) Bond Formation.

An alternative and complementary transformation for the synthesis of aryl- and heteroaryl-substituted alkynes is presented that relies on a chemoselective electrocoupling process. Tetraorganoborate substrates were logically designed and simply accessed by transmetalations using readily or commercially available organotrifluoroborate salts.

Uncommon Four-Membered Building Blocks - Cyclobutenes, Azetines and Thietes.

Strained ring systems have gained considerable importance over the last few years for their implication in natural product syntheses or in drug discovery programs. We present herein a recollection of our work on the construction and functionalization of unsaturated four-membered carbo- and heterocycles in the context of the literature, as well as their applications in further reactions.

The morphology and evolution of chondrichthyan cranial muscles: A digital dissection of the elephantfish Callorhinchus milii and the catshark Scyliorhinus canicula.

The anatomy of sharks, rays, and chimaeras (chondrichthyans) is crucial to understanding the evolution of the cranial system in vertebrates due to their position as the sister group to bony fishes (osteichthyans). Strikingly different arrangements of the head in the two constituent chondrichthyan groups-holocephalans and elasmobranchs-have played a pivotal role in the formation of evolutionary hypotheses targeting major cranial structures such as the jaws and pharynx. However, despite the advent of digital dissections as a means of easily visualizing and sharing the results of anatomical studies in three dimensions, information on the musculoskeletal systems of the chondrichthyan head remains largely limited to traditional accounts, many of which are at least a century old.

Photocatalyzed Transition-Metal-Free Oxidative Cross-Coupling Reactions of Tetraorganoborates*.

Readily accessible tetraorganoborate salts undergo selective coupling reactions under blue light irradiation in the presence of catalytic amounts of transition-metal-free acridinium photocatalysts to furnish unsymmetrical biaryls, heterobiaryls and arylated olefins. This represents an interesting conceptual approach to forge C-C bonds between aryl, heteroaryl and alkenyl groups under smooth photochemical conditions. Computational studies were conducted to investigate the mechanism of the transformation.

Stereoselective Access to Azetidine-Based α-Amino Acids and Applications to Small Peptide Synthesis.

Non-natural azetidine-based amino acids (Aze) present interesting features in protein engineering. A simple organometallic route toward unsaturated carboxylic acid precursors is presented. Subsequent metal-catalyzed asymmetric reduction allowed for the synthesis of a new library of 2-azetidinylcarboxylic acids, which were finally employed in the formation of small peptide chains.

Electro-Olefination-A Catalyst Free Stereoconvergent Strategy for the Functionalization of Alkenes.

Conventional methods carrying out C(sp )-C(sp ) bond formations are typically mediated by transition-metal-based catalysts. Herein, we conceptualize a complementary avenue to access such bonds by exploiting the potential of electrochemistry in combination with organoboron chemistry. We demonstrate a transition metal catalyst-free electrocoupling between (hetero)aryls and alkenes through readily available alkenyl-tri(hetero)aryl borate salts (ATBs) in a stereoconvergent fashion.

Thiete Dioxides as Templates Towards Twisted Scaffolds and Macrocyclic Structures.

Thiete dioxide units have been employed as a template for further functionalization through C-H activation strategies. Using simple thiete dioxide building blocks, a new library of axially chiral molecules has been synthesized that owe their stability to electrostatic interactions in the solid state. Similar starting materials were further engaged in the formation of cyclic trimeric structures, opening the pathway to unprecedented macrocyclic ring systems.

Electrochemical Synthesis of Biaryls via Oxidative Intramolecular Coupling of Tetra(hetero)arylborates.

We report herein versatile, transition metal-free and additive-free (hetero)aryl-aryl coupling reactions promoted by the oxidative electrocoupling of unsymmetrical tetra(hetero)arylborates (TABs) prepared from ligand-exchange reactions on potassium trifluoroarylborates. Exploiting the power of electrochemical oxidations, this method complements the existing organoboron toolbox. We demonstrate the broad scope, scalability, and robustness of this unconventional catalyst-free transformation, leading to functionalized biaryls and ultimately furnishing drug-like small molecules, as well as late stage derivatization of natural compounds.

Atmospheric modeling and source reconstruction of radioactive ruthenium from an undeclared major release in 2017.

In October 2017 unusual Ru detections across most of Europe prompted the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) to analyze the event in order to locate the origin and identify the magnitude of the release. This paper presents the inverse modeling techniques used during the event to achieve this goal. The method is based on a variational approach and consists of using air concentration measurements with the ldX long-range dispersion model included in the IRSN's C3X operational platform.

Single-Pot Access to Bisorganoborinates: Applications in Zweifel Olefination.

Zweifel olefination is a catalyst-free reaction that serves alkene functionalization. While most methods employ commercially available boron pinacol esters, we have assembled a sequence in which the two partners of the formal coupling reaction are installed successively, starting from inexpensive boron alkoxides. The in situ formation of bisorganoborinates was accomplished by consecutive reaction of two different organometallic species.

INITIAL EVALUATION OF INDIVIDUAL DOSES IN THE EARLY PHASE OF A NUCLEAR REACTOR ACCIDENT BASED ON IN-VIVO MONITORING DATA AND SIMULATED RADIOLOGICAL CONSEQUENCES.

In the early phase of a nuclear reactor accident, in-vivo monitoring of impacted population would be highly useful to detect potential contamination during the passage of the cloud and to estimate the dose from inhalation of measured radionuclides. However, it would be important to take into account other exposure components: (1) inhalation of unmeasured radionuclides and (2) external irradiation from the plume and from the radionuclides deposited on the soil. This article presents a methodology to calculate coefficients used to convert in-vivo measurement results directly into doses, not only from the measured radionuclides but from all sources of exposure according to model-based projected doses.

Catalyst-Free Enantiospecific Olefination with In Situ Generated Organocerium Species.

Described is the in situ formation of triorganocerium reagents and their application in catalyst-free Zweifel olefinations. These unique cerium species were generated through novel exchange reactions of organohalides with n-Bu Ce reagents. The adequate electronegativity of cerium allowed for compensating the disadvantages of both usually functional-group-sensitive organolithium species and less reactive organomagnesium reagents.

Chemodivergent and Stereoselective Access to Fused Isoxazoline Azetidines and Thietanes through [3 + 2]-Cycloadditions.

By combining efficient methodologies for the preparation of substituted azetines and thietes with a highly regio- and diastereoselective [3 + 2]-cycloaddition, a straightforward pathway for the synthesis of fused isoxazoline azetidines and thietanes has been designed. With minimal steps and starting from commercial sources, a new library of elaborated architectures was synthesized opening up a new class of molecules with large potential in pharmacology. Finally, a retro [2 + 2]-cycloaddition leading to substituted isoxazoles is described.

Parallel Approaches for the Functionalization of Thietes: α-Metalation versus C-H Activation.

For the first time, an approach to 3,4-disubstituted thietes was developed through two complementary paths. While the first one relies on α-metalation, the second is based on direct C-H functionalization. A new library of sophisticated sulfur-containing four-membered rings is described, paving the way to new bioactive analogues and small heterocycle incorporation.

Merging Art and Science-The 53rd Bürgenstock Conference.

For the 53rd time, the Bürgenstock Conference gathered some of the most gifted scientists and rising stars in organic, physical, and bioorganic chemistry. Orchestrated by Ilan Marek (President) and his successor, Véronique Gouverneur, the synergy between art and science took place in Brunnen, Switzerland, with a beatiful view over Lake Lucerne.

Oxidative Ring Contraction of Cyclobutenes: General Approach to Cyclopropylketones including Mechanistic Insights.

An original oxidative ring contraction of easily accessible cyclobutene derivatives for the selective formation of cyclopropylketones (CPKs) under atmospheric conditions is reported. Comprehensive mechanistic studies are proposed to support this novel, yet unusual, rearrangement. Insights into the mechanism ultimately led to simplification and generalization of the ring contraction of cyclobutenes using mCPBA as an oxidant.

Zirconocene-Mediated Selective C-C Bond Cleavage of Strained Carbocycles: Scope and Mechanism.

Several approaches using organozirconocene species for the remote cleavage of strained three-membered ring carbocycles are described. ω-Ene polysubstituted cyclopropanes, alkylidenecyclopropanes, ω-ene spiro[2.2]pentanes, and ω-ene cyclopropyl methyl ethers were successfully transformed into stereodefined organometallic intermediates, allowing an easy access to highly stereoenriched acyclic scaffolds in good yields and, in most cases, excellent selectivities.

Regiodivergent Stereoselective Access to Fused Alkylideneazetidines.

Following recent advances in the generalization and simplification of 2H-azetine synthesis, a regiodivergent approach to fused 2- and 3-alkylideneazetines was designed via the intermediate formation of unprecedented vinylazetine structures. Concise sequences to the latter are described from which an expected unsaturated fused ring system was isolated with very high yields and regio- and stereoselectivities by [4 + 2] cycloadditions.