Thioxanthone-Based Siloxane Photosensitizer for Cationic/Radical Photopolymerization and Photoinduced Sol-Gel Reactions.

In this investigation, a multifunctional visible-light TX-based photosensitizer containing a siloxane moiety (TXS) was designed with a good overall yield of 54%. The addition of a siloxane moiety enabled the incorporation of a TX photosensitizer into a siloxane network by photoinduced sol-gel chemistry, thus avoiding its release. Both liquid H and solid-state Si NMR measurements undeniably confirmed the formation of photoacids resulting from the photolysis of the TXS/electron acceptor molecule (Iodonium salt), which promoted the photoinduced hydrolysis/condensation of the trimethoxysilane groups of TXS, with a high degree of condensation of its inorganic network.

Sulfur- and Amine- Promoted Multielectron Autoredox Transformation of Nitromethane: Multicomponent Access to Thiourea Derivatives.

Thiourea derivatives are in-demand motifs in organic synthesis, medicinal chemistry and material science, yet redox methods for the synthesis that start from safe, simple, inexpensive and readily available feedstocks are scarce. In this article, we disclose the synthesis of these motifs using elemental sulfur and nitromethane as the starting materials. The method harnesses the multi-electron auto-redox property of nitromethane in the presence of sulfur and amines, delivering thiourea products without any added oxidant or reductant.

Synthesis of Thioureas, Thioamides, and Aza-Heterocycles via Dimethyl-Sulfoxide-Promoted Oxidative Condensation of Sulfur, Malonic Acids, and Amines.

Malonic acid and derivatives have been well-known to undergo monodecarboxylation under relatively mild conditions and have been exclusively used as a C synthon. We report herein their new application as a C synthon via double decarboxylation promoted by sulfur and dimethyl sulfoxide. In the presence of amines as nucleophiles, a wide range of thioureas and thioamides as well as -heterocycles were obtained in good to excellent yields under mild heating conditions.

Exploring economic and environmental efficiency in renewable energy utilization: a case study in the Organization for Economic Cooperation and Development countries.

The share of renewable energy has grown significantly in global energy supply, yet the evaluation of renewable energy utilization has remained limited. Hence, this research explored economic and environmental efficiency in renewable energy utilization in 20 OECD (The Organization for Economic Cooperation and Development) countries from 2015 to 2020. The study approached the data envelopment analysis-slack-based measure (DEA-SBM) to evaluate economic efficiency, and the DEA undesirable output to measure environmental efficiency.

Should Scrotal Color Doppler Ultrasound Be Routinely Indicated in Fertility Evaluation of Non-Azoospermic Men?

Objective: Scrotal ultrasound is not a routine investigation in the clinical approach to male infertility analysis. This study aims to identify the role of testicular Doppler ultrasound in male infertility assessment and its relation to semen parameters in non-azoospermic men.

Methods: Cross-sectional descriptive analysis of 558 men from infertile couples were examined at the Hue Center for Reproductive Endocrinology and Infertility, Hue University Hospital from June 2016 to May 2018.

Nanoporous Polymer Films of Cyanate Ester Resins Designed by Using Ionic Liquids as Porogens.

Novel nanoporous film materials of thermostable cyanate ester resins (CERs) were generated by polycyclotrimerization of dicyanate ester of bisphenol E in the presence of varying amounts (from 20 to 40 wt%) of an ionic liquid (IL), i.e., 1-heptylpyridinium tetrafluoroborate, followed by its quantitative extraction after complete CER network formation.

Hybrid Fibrillar Xerogels with Unusual Magnetic Properties.

We report on the preparation of a hybrid nanomaterial made up of 1D filaments of an antiferromagnetic self-assembling bicopper complex encapsulated in polymer nanofibrils. The encapsulation process is achieved through the heterogeneous nucleation of the growth of polymer fibrils obtained by thermoreversible gelation as shown by calorimetry experiments. Neutron scattering experiments confirm that the filaments of a bicopper complex retain their 1D character after encapsulation in the fibrils.

Ion pairing controls rheological properties of "processionary" polyelectrolyte hydrogels.

We demonstrated recently that polyelectrolytes with cationic moieties along the chain and a single anionic head are able to form physical hydrogels due to the reversible nature of the head-to-body ionic bond. Here we generate a variety of such polyelectrolytes with various cationic moieties and counterion combinations starting from a common polymeric platform. We show that the rheological properties (shear modulus, critical strain) of the final hydrogels can be modulated over three orders of magnitude depending on the cation/anion pair.

Design of Nanohybrid Systems from a Partially Fluorinated Organogelator and Syndiotactic Polystyrene Thermoreversible Gel.

Nanohybrid systems are prepared from organogels of a partially fluorinated molecule and from thermoreversible gels of syndiotactic polystyrene. The thermodynamic behavior, morphology, and structure are investigated by using differential scanning calorimetry, atomic force microscopy, small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS). The outcomes of these investigations suggest that the fibrils of the organogel coil around the sPS fibrils, probably through a heterogeneous nucleation process.

Investigation of the interactions involved in the formation of nanotubes from organogelators.

Investigations into the formation of nanosized structures, particularly nanotubes, by a diamide ester compound are reported. Two aspects are concurrently examined: the role of the solvent and the role of the alkyl chain. The former is addressed by using a benzene derivative (o-xylene) and a totally saturated double ring (trans-decahydronaphthalene) whereas the latter is achieved by replacing the hydrogenous alkyl chain with its fluorinated counterpart while keeping the overall architecture the same.

Extending the limits of precision polymer synthesis: giant polyphenylene dendrimers in the megadalton mass range approaching structural perfection.

The catalyst-free Diels-Alder synthesis of polyphenylene dendrimers with a chromophore core has now been demonstrated to achieve the seventh to ninth generations upon divergent growth. Since standard analytical tools such as size-exclusion chromatography do not provide realistic molecular weights, MALDI-TOF mass spectrometry was applied to characterize the complete series of nine generations. Perfection and monodispersity were thus elucidated at such high masses.

Photoswitchable conductivity in a rigidly dendronized salt.

Light switch: a dendronized salt exhibiting photoswitchable conductivity was designed and synthesized. The salt consists of tetrabutylammonium cations and large, rigidly dendronized borate anions, each bearing eight photoresponsive azobenzene moieties. The conductivity of solutions of this salt can be reversibly switched by irradiation, owing to light-induced changes in the overall size of the dendronized anion and the density of its polyphenylene shell.

Size-selective 2D ordering of gold nanoparticles using surface topography of self-assembled diamide template.

Size-selective organization of ~2 nm dodecanethiol stabilized gold nanoparticles (AuNPs) into periodic 1D arrays by using the surface topographical features of a soft template is described. The template consists of micrometer length nanotapes organized into nanosheets with periodic valleys running along their length and is generated by the hierarchical self-assembly of a diamide molecule (BHPB) in cyclohexane. The AuNP ordering achieved simply by mixing the preformed template with the readily available ~2 nm dodecanethiol stabilized AuNPs is comparable to those obtained using programmable DNA and functional block copolymers.

Aetiologies of central nervous system infection in Viet Nam: a prospective provincial hospital-based descriptive surveillance study.

Background: Infectious diseases of the central nervous system (CNS) remain common and life-threatening, especially in developing countries. Knowledge of the aetiological agents responsible for these infections is essential to guide empiric therapy and develop a rational public health policy. To date most data has come from patients admitted to tertiary referral hospitals in Asia and there is limited aetiological data at the provincial hospital level where most patients are seen.

A fluorescent, shape-persistent dendritic host with photoswitchable guest encapsulation and intramolecular energy transfer.

A fluorescent and photoresponsive host based on rigid polyphenylene dendrimers (PPDs) has been synthesized. The key building block for the divergent dendrimer buildup is a complex tetracyclone 12 containing azobenzenyl, pyridyl, and ethynyl entities. The rigidity of polyphenylenes is of crucial importance for a site-specific placement of different functions: eight azobenzene (AB) moieties into the rigid scaffold, a fluorescent perylenetetracarboxdiimide (PDI) into the core, and eight pyridin functions into the interior cavities.

Direct functionalization of self-assembled nanotubes overcomes unfavorable self-assembling processes.

Diamides containing alkyne and azido were self-assembled into nanotubes and were reacted under their self-assembled state with small molecules by "click chemistry"; the resulting compounds remain self-assembled into new nanotubes that cannot be formed by simple self-assembly of the constituting molecules.