A mixture of an iron or a cobalt carboxylate and an isocyanide ligand catalyzed the hydrosilylation of alkenes with hydrosiloxanes with high efficiency (TON >103) and high selectivity. The Fe ...catalyst showed excellent activity for hydrosilylation of styrene derivatives, whereas the Co catalyst was widely effective in reaction of alkenes. Both of them catalyzed the reaction with allylic ethers. Chemical modification and cross-linking of silicones were achieved by choosing the right catalyst and reaction conditions.
All‐inorganic CsPbX3 (X=I, Br, Cl) perovskite quantum dots (PQDs) have been investigated because of their optical properties, such as tunable wavelength, narrow band, and high quantum efficiency. ...These features have been used in light emitting diode (LED) devices. LED on‐chip fabrication uses mixed green and red quantum dots with silicone gel. However, the ion‐exchange effect widens the narrow emission spectrum. Quantum dots cannot be mixed because of anion exchange. We address this issue with a mesoporous PQD nanocomposite that can prevent ion exchange and increase stability. We mixed green quantum‐dot‐containing mesoporous silica nanocomposites with red PQDs, which can prevent the anion‐exchange effect and increase thermal and photo stability. We applied the new PQD‐based LEDs for backlight displays. We also used PQDs in an on‐chip LED device. Our white LED device for backlight display passed through a color filter with an NTSC value of 113 % and Rec. 2020 of 85 %.
Points of light: Green CsPbBr3 perovskite quantum dots (PQDs), embedded in mesoporous silica (MP), were mixed with red CsPb(Br0.4I0.6)3 quantum dots in a silicone resin and placed on an InGaN blue chip. The green and red QDs were excited by blue light with λ=450 nm. The resulting PQD white light emitting diode (LED) exhibits a wide color gamut because of its narrow emission wavelength.
Peningkatan polutan logam berat kadmium (Cd) di persawahan menjadi masalah lingkungan yang serius karena dapat menimbulkan toksisitas dan berakibat pada penurunan pertumbuhan tanaman pangan yang ...tidak toleran. Gejala toksisitas Cd pada tanaman dapat dikurangi dengan memanfaatkan unsur benefisial seperti silikon (Si). Namun, peran Si dalam mengurangi gejala toksisitas Cd pada padi ‘Cempo Merah’ belum banyak diteliti. Tujuan penelitian ini yaitu mengkaji peran Si dalam meningkatkan pertumbuhan dan kadar klorofil padi ‘Cempo Merah’ yang tercekam logam berat Cd. Penelitian ini menggunakan desain Rancangan Acak Lengkap 2 Faktorial, yakni perlakuan 3CdSO4.H2O dan CaSiO3 (masing-masing dengan konsentrasi 0, 50, dan 100 mg.kg-1 tanah), dengan 3 kali ulangan. Data penelitian dianalisis menggunakan ANOVA (analisis sidik ragam) dan uji DMRT (Duncan Multiple Range Test) pada p<0,05. Hasil penelitian menunjukkan bahwa perlakuan Si (100 mg.kg-1 tanah) efektif meningkatkan pertumbuhan dan kadar klorofil padi ‘Cempo Merah’ baik dalam kondisi tidak tercekam maupun tercekam logam berat Cd.
Abstract
Increasing cadmium (Cd) in rice fields become a serious environmental problem because it can cause toxicity and decrease the growth of intolerant food crops. These toxicity symptoms can be reduced by utilizing beneficial elements such as silicon (Si). However, its role in rice 'Cempo Merah' has not been much studied. This study aimed to examine the role of Si in increasing the growth and chlorophyll content in the rice ‘Cempo Merah’ under Cd stress. This study used a Complete Randomized Design, two factorials, namely 3CdSO4.H2O and CaSiO3 (each with 0, 50, and 100 mg.kg-1 of soil concentrations), with 3 replications. The research data were analyzed using ANOVA and Duncan’s test at p <0.05. The results showed that Si (100 mg.kg-1 ) effectively increased the growth and chlorophyll content in rice both under Cd stress and normal conditions.
Key words: silicon, cadmium, growth, chlorophyll, rice
Abstrak
Peningkatan polutan logam berat kadmium (Cd) di persawahan menjadi masalah lingkungan yang serius karena dapat menimbulkan toksisitas dan berakibat pada penurunan pertumbuhan tanaman pangan yang tidak toleran. Gejala toksisitas Cd pada tanaman dapat dikurangi dengan memanfaatkan unsur benefisial seperti silikon (Si). Namun, peran Si dalam mengurangi gejala toksisitas Cd pada padi ‘Cempo Merah’ belum banyak diteliti. Tujuan penelitian ini yaitu mengkaji peran Si dalam meningkatkan pertumbuhan dan kadar klorofil padi ‘Cempo Merah’ yang tercekam logam berat Cd. Penelitian ini menggunakan desain Rancangan Acak Lengkap 2 Faktorial, yakni perlakuan 3CdSO4.H2O dan CaSiO3 (masing-masing dengan konsentrasi 0, 50, dan 100 mg.kg-1 tanah), dengan 3 kali ulangan. Data penelitian dianalisis menggunakan ANOVA (analisis sidik ragam) dan uji DMRT ( Duncan Multiple Range Test ) pada p<0,05. Hasil penelitian menunjukkan bahwa perlakuan Si (100 mg.kg-1 tanah) efektif meningkatkan pertumbuhan dan kadar klorofil padi ‘Cempo Merah’ baik dalam kondisi tidak tercekam maupun tercekam logam berat Cd.
Kata kunci: silikon, kadmium, pertumbuhan, padi
Silicon has long been regarded as a prospective anode material for lithium-ion batteries. However, its huge volumetric changes during cycling are a major obstacle to its commercialization, as these ...changes result in irreversible cracking and disconnection of the active mass from the current collector, as well as an excessive formation of a highly resistive solid electrolyte interphase. Multiple mechanical stress relief strategies that primarily use silicon nanostructurization have been previously developed. However, despite the significant improvements on the active material cycle life, using nanomaterials still results in complications, such as low conductivity, reduced volumetric energy density, and increased side reactions. This work provides a historical context for the development of silicon anodes and focuses on the surface chemistry and structural integrity of the electrode, thereby highlighting the most effective strategies reported recently for their optimization.
Superoleophobic surfaces were fabricated by using organosilanes. The surfaces feature high contact angles and ultralow sliding angles for various nonpolar liquids, excellent transparency, and ...chemical and environmental stability. The microstructure and superoleophobicity of the surfaces can be regulated simply by the water concentration in toluene used during the coating procedure.
Tetramethylammonium silanolate-initiated ring-opening copolymerization of octamethylcyclotetrasiloxane (D4) and bis(heptamethylcyclotetrasiloxanyl)ethane (bis-D4) renders cross-linked network ...polymers that contain ethylene bridges and active silanolate end groups. These “living” reactive anionic species are not neutralized by ambient atmosphere exposure (are stable to water, oxygen, CO2) and promote thermally activated equilibration among different network isomers and cyclic oligomers. The cross-link density of these living networks can be controlled by the ratio of D4:bis-D4, and the density of active chain ends is determined from the initiator:monomer ratio. We report that samples prepared with particular ratios of initiator:D4:bis-D4 can be cut with a sharp knife, even into two pieces, and can heal by siloxane equilibration to restore the original strength of the silicone sample. Fracture toughness measurements were carried out and revealed complete (mechanical) healing. Broken and healed samples generally failed in locations other than the initially cracked region. We call attention to publications and patents from the 1950s that suggest that this self-healing behavior was likely obvious 60 years ago.
Healable silicone materials have great technical impact in coatings, smart actuators, and flexible electronics, however, current healable silicone materials lack mechanical tunability. Herein, we ...designed and synthesized a new type of healable silicone through hydrogen‐bond assisted multiphase assembly of siloxane oligomers. Besides the enhanced mechanical strength, unique water‐enhanced healing was observed in the polymer network which is due to the reversible dissociation/association of multivalent hydrogen bonds in the presence of water.
Well healed: A new type of supramolecular polymer with water‐enhanced healing was prepared from a self‐assembled oligomer network with multivalent hydrogen bonds assisted crystallization and multiphase separation. Reversible dissociation/association of the multivalent hydrogen bonds in the presence of water provides the mechanism of water‐enhanced healing.
Losing contact: Omniphobic surfaces can be readily produced by acid‐catalyzed graft polycondensation of dimethyldimethoxysilane (PDMS). Droplets show a very small contact angle hysteresis as well as ...a low sliding angle of only a few degrees. The nm‐thick PDMS layer is neither easily washed away nor depleted. This method offers a novel approach towards the preparation of super‐liquid‐repelling surfaces.
Expansion on stiff culture substrates activates pro-fibrotic cell programs that are retained by mechanical memory. Here, we show that priming on physiologically soft silicone substrates suppresses ...fibrogenesis and desensitizes mesenchymal stem cells (MSCs) against subsequent mechanical activation in vitro and in vivo, and identify the microRNA miR-21 as a long-term memory keeper of the fibrogenic program in MSCs. During stiff priming, miR-21 levels were gradually increased by continued regulation through the acutely mechanosensitive myocardin-related transcription factor-A (MRTF-A/MLK-1) and remained high over 2 weeks after removal of the mechanical stimulus. Knocking down miR-21 once by the end of the stiff-priming period was sufficient to erase the mechanical memory and sensitize MSCs to subsequent exposure to soft substrates. Soft priming and erasing mechanical memory following cell culture expansion protects MSCs from fibrogenesis in the host wound environment and increases the chances for success of MSC therapy in tissue-repair applications.
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