Month: December 2022

Valencia, L. M. published the artcileInduced damage during STEM-EELS analyses on acrylic-based materials for Stereolithography, SDS of cas: 15625-89-5, the publication is Polymer Degradation and Stability (2022), 110044, database is CAplus.

(Scanning) transmission electron microscopy, (S)TEM, offers a powerful characterization tool based on electron-matter interactions, highly valuable in materials science. However, the possible electron beam induced damage during (S)TEM measurements hinders the anal. of soft materials, such as acrylic resins. Importantly, acrylic resins offer an appealing playground for the development of novel composites with customized properties and convenient processing capabilities for 3D-printing technologies, including Stereolithog. (SLA). There are several factors preventing the optimal performance of TEM measurements applied to acrylic resins, among which we focus on the quality of the analyzed specimen (i.e., compromise between thickness and robustness, to achieve electron transparency while keeping the material integrity), particularly challenging when working with soft materials; the electrostatic charging/discharging effects, resulting in sample drift and related noise/artifacts; and the radiolysis and knock-on electron-induced damage, which directly degrade the material under study. We explore and compare different methodologies to obtain resin specimens suitable for (S)TEM anal., employed for the subsequent study of the electron-beam damage induced during STEM-EELS measurements. Furthermore, we propose likely underlying mechanisms explaining the acrylic resin degradation based on the different EELS monitored signals. On one hand, we assess the evolution of the carbon and oxygen content, as well as the material thinning as a function of the accumulated electron dose. On the other hand, we extract meaningful information from the spectral shape of carbon and oxygen K-edges upon increasing electron doses, unraveling likely degradation pathways. The earned understanding on the electron-beam induced damage and the determination of critical doses provide a useful framework for the implementation of (S)TEM techniques as useful tools to help in the smart engineering of acrylic-based composites for SLA.

Polymer Degradation and Stability published new progress about 15625-89-5. 15625-89-5 belongs to esters-buliding-blocks, auxiliary class Polymerization Reagents,Crosslinkers, name is Trimethylolpropane triacrylate, and the molecular formula is C5H5BrN2, SDS of cas: 15625-89-5.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Naidoo, Jacinth published the artcileDiscovery of a Neuroprotective Chemical, (S)-N-(3-(3,6-Dibromo-9H-carbazol-9-yl)-2-fluoropropyl)-6-methoxypyridin-2-amine [(-)-P7C3-S243], with Improved Druglike Properties, Category: esters-buliding-blocks, the publication is Journal of Medicinal Chemistry (2014), 57(9), 3746-3754, database is CAplus and MEDLINE.

(-)-P7C3-S243 (I) is a neuroprotective aminopropyl carbazole with improved druglike properties compared with previously reported compounds in the P7C3 class. It protects developing neurons in a mouse model of hippocampal neurogenesis and protects mature neurons within the substantia nigra in a mouse model of Parkinson’s disease. A short, enantioselective synthesis provides the neuroprotective agent in optically pure form. It is nontoxic, orally bioavailable, metabolically stable, and able to cross the blood-brain barrier. As such, it represents a valuable lead compound for the development of drugs to treat neurodegenerative diseases and traumatic brain injury.

Journal of Medicinal Chemistry published new progress about 115314-17-5. 115314-17-5 belongs to esters-buliding-blocks, auxiliary class Epoxides,Chiral,Nitro Compound,Sulfonate,Benzene, name is (R)-Oxiran-2-ylmethyl 3-nitrobenzenesulfonate, and the molecular formula is C9H9NO6S, Category: esters-buliding-blocks.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

McDonough, L. M. published the artcileApple ermine moth, Yponomeuta malinellus Zeller: two components of female sex pheromone gland highly effective in field trapping tests, Safety of (Z)-Dodec-9-en-1-yl acetate, the publication is Journal of Chemical Ecology (1990), 16(2), 477-86, database is CAplus and MEDLINE.

When electroantennog. responses of male Y. malinellus to model compounds were determined at dosages of 0.3-30 ng, the strongest responses were obtained from (Z)-9-dodecen-1-ol acetate (Z9-12:Ac). Also, strong responses were obtained from (Z)-11-tetradecenal (Z11-14:Al) and (Z)-11-tetradecen-1-ol (Z11-14:OH). At a dosage of 0.3 ng, Z11-14:Al produced a stronger response than Z11-14:OH, while at a dosage of 30 ng, Z11-14:OH and Z11-14:Al produced equal responses. Gas chromatog. and mass spectral anal. of extracts of female sex pheromone glands showed the presence of Z9-12:Ac, tetradecan-1-ol (14:OH), (E)-11-tetradecen-1-ol (E11-14:OH), Z11-14:OH, hexadecan-1-ol, and hexadecan-1-ol acetate in a ratio of 0.6:200:37:100:140:35. In field tests, Z9-12:Ac and Z11-14:OH together were required for trap catch, and addition of Z11-14:Al, E11-14:OH, 14:OH, or (Z)-11-tetradecen-1-ol acetate did not increase catch. Ratios in rubber spectra of 0.5:99.5 to 1.5:98.5 (Z9-12:Ac/Z11-14:OH) captured the most males and captures were statistically equivalent for dosages of 10-1000 μg/rubber septum. Traps baited with the synthetic lure produced better catches than those baited with females.

Journal of Chemical Ecology published new progress about 16974-11-1. 16974-11-1 belongs to esters-buliding-blocks, auxiliary class Aliphatic Chain, name is (Z)-Dodec-9-en-1-yl acetate, and the molecular formula is C14H26O2, Safety of (Z)-Dodec-9-en-1-yl acetate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Sauerland, Max B. published the artcileElectrophile versus oxidant modification of cysteine residues: Kinetics as a key driver of protein modification, Application of Dimethyl fumarate, the publication is Archives of Biochemistry and Biophysics (2022), 109344, database is CAplus and MEDLINE.

A review. Humans have widespread exposure to both oxidants, and soft electrophilic compounds such as alpha,beta-unsaturated aldehydes and quinones. Electrophilic motifs are commonly found in a drugs, industrial chems., pollutants and are also generated via oxidant-mediated degradation of biomols. including lipids (e.g. formation of 4-hydroxynonenal, 4-hydroxyhexenal, prostaglandin J2). All of these classes of compounds react efficiently with Cys residues, and the particularly the thiolate anion, with this resulting in Cys modification via either oxidation or adduct formation. This can result in deleterious or beneficial effects, that are either reversible (e.g. in cell signalling) or irreversible (damaging). For example, acrolein is a well-established toxin, whereas dimethylfumarate is used in the treatment of multiple sclerosis and psoriasis. This short review discusses the targets of alpha,beta-unsaturated aldehydes, and particularly two prototypic cases, acrolein and dimethylfumarate, and the factors that control the selectivity and kinetics of reaction of these species. Comparison is made between the reactivity of oxidants vs. soft electrophiles. These rate constants indicate that electrophiles can be significant thiol modifying agents in some situations, as they have rate constants similar to or greater than species such as H2O2, can be present at higher concentrations, and are less efficiently removed by protective systems when compared to H2O2. They may also induce similar or higher levels of modification than highly reactive oxidants, due to the very low concentrations of oxidants formed in most in vivo situations.

Archives of Biochemistry and Biophysics published new progress about 624-49-7. 624-49-7 belongs to esters-buliding-blocks, auxiliary class Inhibitor,Natural product, name is Dimethyl fumarate, and the molecular formula is C6H8O4, Application of Dimethyl fumarate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Savoji, Houman published the artcile3D Printing of Vascular Tubes Using Bioelastomer Prepolymers by Freeform Reversible Embedding, Application In Synthesis of 617-52-7, the publication is ACS Biomaterials Science & Engineering (2020), 6(3), 1333-1343, database is CAplus and MEDLINE.

Bioelastomers have been extensively used in tissue engineering applications because of favorable mech. stability, tunable properties, and chem. versatility. As these materials generally possess low elastic modulus and relatively long gelation time, it is challenging to 3D print them using traditional techniques. Instead, the field of 3D printing has focused preferentially on hydrogels and rigid polyester materials. To develop a versatile approach for 3D printing of elastomers, we used freeform reversible embedding of suspended prepolymers. A family of novel fast photocrosslinakble bioelastomer prepolymers were synthesized from di-Me itaconate, 1,8-octanediol, and tri-Et citrate. Tensile testing confirmed their elastic properties with Young’s moduli in the range of 11-53 kPa. These materials supported cultivation of viable cells and enabled adhesion and proliferation of human umbilical vein endothelial cells. Tubular structures were created by embedding the 3D printed microtubes within a secondary hydrogel that served as a temporary support. Upon photocrosslinking and porogen leaching, the polymers were permeable to small mols. (TRITC-dextran). The polymer microtubes were assembled on the 96-well plates custom made by hot-embossing, as a tool to connect multiple organs-on-a-chip. The endothelialization of the tubes was performed to confirm that these microtubes can be utilized as vascular tubes to support parenchymal tissues seeded on them.

ACS Biomaterials Science & Engineering published new progress about 617-52-7. 617-52-7 belongs to esters-buliding-blocks, auxiliary class Alkenyl,Aliphatic hydrocarbon chain,Ester, name is Dimethyl itaconate, and the molecular formula is C7H10O4, Application In Synthesis of 617-52-7.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Kwak, Se Hun published the artcileN-Iminopyridinium ylide-directed, cobalt-catalysed coupling of sp² C-H bonds with alkynes, HPLC of Formula: 1877-71-0, the publication is Chemical Communications (Cambridge, United Kingdom) (2020), 56(75), 11070-11073, database is CAplus and MEDLINE.

N-Iminopyridinium ylides were competent monodentate directing groups for cobalt-catalyzed annulation of sp² C-H bonds with internal alkynes. The pyridine moiety in the ylide serves as an internal oxidant and was cleaved during the reaction. The annulation reactions possess excellent compatibility with heterocyclic substrates, tolerating furan, thiophene, pyridine, pyrrole, pyrazole, and indole functionalities.

Chemical Communications (Cambridge, United Kingdom) published new progress about 1877-71-0. 1877-71-0 belongs to esters-buliding-blocks, auxiliary class Carboxylic acid,Benzene,Ester, name is 3-(Methoxycarbonyl)benzoic acid, and the molecular formula is C9H8O4, HPLC of Formula: 1877-71-0.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Kwak, Se Hun published the artcileN-Aminopyridinium Ylide-Directed, Copper-Promoted Amination of sp² C-H Bonds, Quality Control of 1877-71-0, the publication is Journal of Organic Chemistry (2019), 84(20), 13022-13032, database is CAplus and MEDLINE.

N-Aminopyridinium ylides were used as monodentate directing groups for copper-promoted C-H/N-H coupling of sp² C-H bonds with pyrazoles, imidazoles, and sulfonamides. Reactions proceed in fluorinated alc. solvents at elevated temperatures and require use of 1.3-3 equiv of copper(II) acetate. This appears to be the first method for copper-promoted C-H/N-H coupling directed by a removable monodentate auxiliary in absence of added ligands.

Journal of Organic Chemistry published new progress about 1877-71-0. 1877-71-0 belongs to esters-buliding-blocks, auxiliary class Carboxylic acid,Benzene,Ester, name is 3-(Methoxycarbonyl)benzoic acid, and the molecular formula is C9H8O4, Quality Control of 1877-71-0.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Sartwell, Charles published the artcileMating disruption of western pine shoot borer (Lepidoptera: Tortricidae) with widely spaced releasers of synthetic pheromone, COA of Formula: C14H26O2, the publication is Journal of Economic Entomology (1983), 76(5), 1148-51, database is CAplus.

Damage by Eucosma sonomana to Pinus ponderosa was significantly reduced (46-73%) by mating disruption with low seasonal dosages (3.5-5 g/ha) of a synthetic pheromone, a 4:1 mixture of (Z)-9- [16974-11-1] and (E)-9-dodecenyl acetate  [35148-19-7], released from widely spaced (20-50 m) point sources in 3 Oregon tests covering 225 ha. Com. available Hercon laminated type dispensers were as effective as laboratory-prepared polyvinyl chloride releasers.

Journal of Economic Entomology published new progress about 16974-11-1. 16974-11-1 belongs to esters-buliding-blocks, auxiliary class Aliphatic Chain, name is (Z)-Dodec-9-en-1-yl acetate, and the molecular formula is C14H26O2, COA of Formula: C14H26O2.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Dey, Tanmay published the artcileApoplastic reactive oxygen species mediated escape growth of root during illumination in Vigna radiata (L.) Wilczek seedlings, Name: Propyl 3,4,5-trihydroxybenzoate, the publication is Acta Physiologiae Plantarum (2021), 43(11), 145, database is CAplus.

Besides gravity, roots are also guided by light to grow deep into the soil and sensitivity of roots to light is evidently due to presence of photoreceptors like phototropins. Such light-induced root growth (light-escape growth) presumably involves reactive oxygen species (ROS). Present study explores the possibility of ROS action in this event during early seedling growth of Vigna radiata based on pharmacol. evidences. Germinated (20 h) seeds were incubated in dark or light in presence of general ROS scavenger (Pr gallate), specific scavengers of O^·₂^– (copper chloride; CuCl₂), H₂O₂ [dimethylthiourea (DMTU) and potassium iodide (KI)] and ^·OH (sodium benzoate) and ROS-producing enzyme inhibitors [zinc chloride (ZnCl₂), inhibitor of NADPH oxidase (NOX); diethyldithiocarbamate (DEDTC), inhibitor of superoxide dismutase (SOD) and salicylhydroxamic acid (SHAM), inhibitor of peroxidase]. Light-induced root growth of 3-day seedlings diminished signifcantly in case of all the treatments suggesting for a pos. role of ROS in light-escape growth. This is supported by elevated level of apoplastic ROS in light grown roots as evident from ROS-specific staining [nitroblue tetrazolium chloride (NBT) for O^·₂^– and 3,3,5,5-tetramethylbenzidine (TMB) for H₂O₂] and spectrophotometric estimation of apoplastic ROS production (O^·₂^– and H₂O₂). In addition, higher activity of membrane bound NOX (producing O^·₂^– ) and apoplastic class III peroxidase (Prx, producing ^·OH) in light grown roots further corroborates the view that apoplastic ROS (initiated with NOX-generated O^·₂^– , which is converted, either spontaneously or by the activity of SOD, to H₂O₂ and further metabolized by Prx to ^·OH that participates in cell wall relaxation required for growth) is instrumental in light-escape growth of roots.

Acta Physiologiae Plantarum published new progress about 121-79-9. 121-79-9 belongs to esters-buliding-blocks, auxiliary class Natural product, name is Propyl 3,4,5-trihydroxybenzoate, and the molecular formula is C10H12O5, Name: Propyl 3,4,5-trihydroxybenzoate.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics

Shershnev, Ivan published the artcileThe use of α-diazo-γ-butyrolactone in the Buchner-Curtius-Schlotterbeck reaction of cyclic ketones: A facile entry into spirocyclic scaffolds, Related Products of esters-buliding-blocks, the publication is Tetrahedron Letters (2019), 60(27), 1800-1802, database is CAplus.

The first example of the Buchner-Curtius-Schlotterbeck reaction of cyclic ketones with a stabilized cyclic diazo compound partner is described. The approach towards spirocyclic scaffolds has been exemplified with readily available α-diazo-γ-butyrolactone. The reaction proved to be viable with BF₃·OEt₂ as the preferred catalyst and displayed substantial sensitivity to the size of the cyclic ketone.

Tetrahedron Letters published new progress about 517-23-7. 517-23-7 belongs to esters-buliding-blocks, auxiliary class Tetrahydrofuran,Ketone,Ester, name is 3-Acetyldihydrofuran-2(3H)-one, and the molecular formula is C5H6BNO2, Related Products of esters-buliding-blocks.

Referemce:
https://en.wikipedia.org/wiki/Ester,
Ester – an overview | ScienceDirect Topics