Dynamic Interactions of a Cable-Laying Vessel with a Submarine Cable during Its Landing Process

The rapid development of offshore electricity grid construction has led to a great demand for submarine cable deployment. In this study, a numerical model is established based on the commercial software ANSYS-AQWA to investigate the dynamic interactions between a cable-laying vessel and a submarine cable during its landing process, which has not yet been reported and is critical to the safety of the cable. The numerical model was validated by an experimental test on the mooring stability of a vessel conducted in a wave tank. The effects of the cable length, the current velocity, the incident wave, and the wind direction on vessel stability and the tensions in the mooring lines and cable were investigated. When the cable length is short, the submarine cable acts as a mooring cable that can stabilize the hull, but it is not safe to apply force to the submarine cable. At the same time, an increase in the current speed also increases the tensile force of the submarine cable. The influence of different incident wave directions and wind directions on the stability and tension of ships in mooring lines and cables was studied, and the most unfavorable environmental conditions for submarine cable laying were determined under different environmental conditions

Difluorination of Furonaphthoquinones

An unprecedented difluorination reaction was developed based on the furonaphthoquinone skeleton of natural products tanshinones and their analogues. By using Selectfluor as the fluorinating source and H₂O as the hydroxyl source, a wide range of unique polycyclic α,α-difluoro β,β-dihydroxyl <i>para</i>-quinone products were achieved with yields up to 90%. The mechanistic studies revealed that the reaction might undergo tandem multiple electrophilic and nucleophilic substitutions, as well as cleavages of C–O and C–C bonds. This approach not only provides a new method to synthesis of α,α-difluoro ketones, but also affords a series of unique chemotypes for biological activity screening

A Genome-Wide mRNA Expression Profile in Caenorhabditis elegans under Prolonged Exposure to 1750MHz Radiofrequency Fields.

OBJECTIVE:C. elegans has been used as a biomonitor for microwave-induced stress. However, the RF (radiofrequency) fields that have been used in previous studies were weak (≤1.8W/kg), and the bio-effects on C. elegans were mostly negative or ambiguous. Therefore, this study used more intense RF fields (SAR = 3W/kg) and longer time course of exposure (60h at 25°C, L1 stage through adult stage) to investigate the biological consequences of 1750 MHz RF fields in wild-type worms. METHODS:The growth rates and lifespans of RF-exposure group and the control group were carefully recorded. RNA samples were collected at L4 (35h) and gravid adult (50h) stages for further high-throughput sequencing, focusing on differences between the RF-exposure and the sham control groups. RESULTS:The RF-exposed and sham control groups developed at almost the same rate and had similar longevity curves. In L4 stage worms, 94 up-regulated and 17 down-regulated genes were identified, while 186 up-regulated and 3 down-regulated genes were identified in adult stage worms. GO analysis showed that the differentially expressed genes at 35h were associated with growth, body morphogenesis and collagen and cuticle-based development. Genes that were linked to growth rate and reproductive development were differentially expressed at 50h. Some embryonic and larval development genes in the offspring were also differentially expressed at 50h. Ten genes were differentially expressed at both 35h and 50h, most of which were involved in both embryonic and larval developmental processes. Although prolonged RF fields did not induce significant temperature increase in RF exposure groups, the temperature inside worms during exposure was unknown. CONCLUSIONS:No harmful effects were observed in prolonged exposure to 1750 MHz RF fields at SAR of 3W/kg on development and longevity of C. elegans. Although some differentially expressed genes were found after prolonged RF exposure, these differences were ascribed to oscillating gene expression patterns in L4 and gravid adult worms. It was also difficult to rule out a weak thermal effect caused by prolonged RF exposure inside the worms

Rh(III)-Catalyzed Intermolecular C–H Amination of 1‑Aryl‑1<i>H</i>‑pyrazol-5(4<i>H</i>)‑ones with Alkylamines

An intermolecular C–H amination of 1-aryl-1<i>H</i>-pyrazol-5­(4<i>H</i>)-ones was achieved under mild reaction conditions, using a low catalyst loading and with a broad scope of aminating reagents. This protocol not only provides the first example of rhodium­(III)-catalyzed intermolecular aromatic C–H amination directed by an intrinsic functionality of the substrate/product but also features aminating an existing drug with either primary or secondary <i>N</i>-benzoate alkylamines as the coupling partners

Molecular editing of aza-arene C-H bonds by distance, geometry and chirality.

Direct molecular editing of heteroarene carbon-hydrogen (C-H) bonds through consecutive selective C-H functionalization has the potential to grant rapid access into diverse chemical spaces, which is a valuable but often challenging venture to achieve in medicinal chemistry1. In contrast to electronically biased heterocyclic C-H bonds2-9, remote benzocyclic C-H bonds on bicyclic aza-arenes are especially difficult to differentiate because of the lack of intrinsic steric/electronic biases10-12. Here we report two conceptually distinct directing templates that enable the modular differentiation and functionalization of adjacent remote (C6 versus C7) and positionally similar (C3 versus C7) positions&nbsp;on bicyclic aza-arenes through careful modulation of distance, geometry and previously unconsidered chirality in template design. This strategy enables direct C-H olefination, alkynylation and allylation at adjacent C6 and C7 positions of quinolines in the presence of a competing C3 position that is spatially similar to C7. Notably, such site-selective, iterative and late-stage C-H editing of quinoline-containing pharmacophores can be performed in a modular fashion in different&nbsp;orders to suit bespoke synthetic applications. This Article, in combination with previously reported complementary methods, now fully establishes a unified late-stage molecular editing strategy to directly modify bicyclic aza-arenes at any given site in different orders

Rh(III)-Catalyzed Intermolecular C–H Amination of 1‑Aryl‑1<i>H</i>‑pyrazol-5(4<i>H</i>)‑ones with Alkylamines

An intermolecular C–H amination of 1-aryl-1<i>H</i>-pyrazol-5­(4<i>H</i>)-ones was achieved under mild reaction conditions, using a low catalyst loading and with a broad scope of aminating reagents. This protocol not only provides the first example of rhodium­(III)-catalyzed intermolecular aromatic C–H amination directed by an intrinsic functionality of the substrate/product but also features aminating an existing drug with either primary or secondary <i>N</i>-benzoate alkylamines as the coupling partners

Rational Development of Remote C−H Functionalization of Biphenyl: Experimental and Computational Studies

A simple and efficient nitrile-directed meta-C-H olefination, acetoxylation, and iodination of biaryl compounds is reported. Compared to the previous approach of installing a complex U-shaped template to achieve a molecular U-turn and assemble the large-sized cyclophane transition state for the remote C-H activation, a synthetically useful phenyl nitrile functional group could also direct remote meta-C-H activation. This reaction provides a useful method for the modification of biaryl compounds because the nitrile group can be readily converted to amines, acids, amides, or other heterocycles. Notably, the remote meta-selectivity of biphenylnitriles could not be expected from previous results with a macrocyclophane nitrile template. DFT computational studies show that a ligand-containing Pd-Ag heterodimeric transition state (TS) favors the desired remote meta-selectivity. Control experiments demonstrate the directing effect of the nitrile group and exclude the possibility of non-directed meta-C-H activation. Substituted 2-pyridone ligands were found to be key in assisting the cleavage of the meta-C-H bond in the concerted metalation-deprotonation (CMD) process

Rational Development of Remote C−H Functionalization of Biphenyl: Experimental and Computational Studies

A simple and efficient nitrile-directed meta-C-H olefination, acetoxylation, and iodination of biaryl compounds is reported. Compared to the previous approach of installing a complex U-shaped template to achieve a molecular U-turn and assemble the large-sized cyclophane transition state for the remote C-H activation, a synthetically useful phenyl nitrile functional group could also direct remote meta-C-H activation. This reaction provides a useful method for the modification of biaryl compounds because the nitrile group can be readily converted to amines, acids, amides, or other heterocycles. Notably, the remote meta-selectivity of biphenylnitriles could not be expected from previous results with a macrocyclophane nitrile template. DFT computational studies show that a ligand-containing Pd-Ag heterodimeric transition state (TS) favors the desired remote meta-selectivity. Control experiments demonstrate the directing effect of the nitrile group and exclude the possibility of non-directed meta-C-H activation. Substituted 2-pyridone ligands were found to be key in assisting the cleavage of the meta-C-H bond in the concerted metalation-deprotonation (CMD) process

Unified Template Strategy for Editing Multiple Remote C–H Bonds

Through consecutive selective C–H functionalization at multiple sites, the direct molecular editing of heteroarene carbon-hydrogen (C–H) bonds has the potential to grant rapid access into diverse molecular space; a valuable but often challenging venture to achieve in medicinal chemistry. Contrasting with electronically-biased heterocyclic C–H bonds, remote benzocyclic C–H bonds on bicyclic aza-arenes are especially difficult to differentiate due to lack of intrinsic steric/electronic biases. Through careful consideration of distance and geometric parameters, we herein report a unified catalytic directing template strategy that enables the modular functionalization of chemically-similar and adjacent remote positions on bicyclic aza-arene scaffolds. Differentiated by using two structurally distinct catalytic directing templates, this method enables direct C–H olefination, alkynylation, and allylation at previously inaccessible C6 and C7 positions of quinolines, and is amenable to the iterative, modular, and late-stage C–H editing of quinoline-containing pharmacophores and pharmaceuticals. This report, in combination with our previous C5-selective template and other complementary methods, now fully establishes a unified ‘molecular editing’ strategy to directly modify aza-arene heterocycles at any given site

Monomeric Octahedral Ruthenium(II) Complex Enabled <i>meta</i>-C–H Nitration of Arenes with Removable Auxiliaries

A removable oxime-assisted <i>meta</i>-C–H nitration of arenes is reported. Mechanistic investigations and DFT calculations reveal a new monomeric octahedral ruthenium­(II) complex is responsible for the meta-selective nitration. Dioxygen as a cooxidant is crucial for achieving high conversion and good yields. Moreover, the utility of the present reaction protocol is further showcased by the late-stage modification of the clinical CNS drugs Diazepam and Fluvoxamine