Assembly of Hybrid Oligonucleotide Modified Gold (Au) and Alloy Nanoparticles Building Blocks

2006 ◽  
Vol 6 (1) ◽  
pp. 95-100 ◽  
Author(s):  
Yu-Ching Kuo ◽  
Chun-Ping Jen ◽  
Yu-Hung Chen ◽  
Chia-Hao Su ◽  
Shu-Hui Tsai ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Melting Temperature ◽  
Hybrid Materials ◽  
Building Blocks ◽  
Au Nanoparticle ◽  
Molar Ratio ◽  
Alloy Nanoparticles ◽  
Modified Model ◽  
Nanoparticle Composites

The alloy-based hybrid materials with macroscopic network arrays were developed by AuAg/Au and AuAgPd/Au nanoparticle composites through oligonucleotides hybridization. AuAg/Au and AuAgPd/Au exhibited distinct organization. The morphology of AuAg/Au conjugation assembled mainly as compact aggregates while AuAgPd/Au hybrid conjugated into the loosen network assemblies. The dehybridization temperatures were studied as a function of molar ratio of alloy/Au. It was found that higher alloy/gold molar ratio led to stronger hybridization for alloy/gold composite, accompanied with increased melting temperature. These results could be interpreted in terms of more alloy nanoparticles bound to a Au particle when the molar ratio of alloy/gold increased. The thermal analysis also showed that AuAg/Au exhibited higher dehybridization temperature. A modified model describing the dehybridization probability of an intact Au/alloy aggregate was performed to support the dehybridization temperature increased with increasing alloy/Au molar ratio. As to more oligonucleotides carried by AuAg (4.9 ± 1.9 nm) than by AuAgPd (4.4 ± 1.5 nm) due to larger size in AuAg, the efficient hybridization could result in higher dehybridization temperature in AuAg/Au.

scholarly journals Preparation of Silicophosphate Alternating Hybrid Copolymers via Nonaqueous Acid-Base Reactions of Phosphoric Acid and Organo-Bridged Bis(chlorosilane)

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 127
Author(s):  
Kenji Okada ◽  
Masanari Takano ◽  
Yasuaki Tokudome ◽  
Yomei Tokuda ◽  
Masahide Takahashi
Keyword(s):  
Phosphoric Acid ◽  
Hybrid Materials ◽  
Level Structure ◽  
Phosphorous Acid ◽  
Building Blocks ◽  
Molar Ratio ◽  
Network Structures ◽  
Acid Base ◽  
Alternating Copolymer ◽  
Silicon Based

A design of atomic and oligomer level structure in organic-inorganic hybrid materials is highly important for various applications. Nonaqueous acid-base reaction allows us to prepare silicophosphates with controlled inorganic networks (–(O–P–O–Si)n) at atomic level because phosphorous and silicon-based precursors can react directly, resulting in an alternating copolymer network. Organic functionalization in those materials has been realized so far by using organic-modified phosphorous acid and/or organo-chlorosilane as precursors. In the present study, silicophosphate oligomers exhibiting inorganic-organic hybrid chains of (–(O–P–O–Si–R–Si)n) (R: bridging organic functional groups), are prepared from phosphoric acid and organo-bridged bis(chlorosilane). The 1, 2-bis(chlorodimethylsilyl)ethane ((C2H4)(Me2SiCl)2) and 1, 4-bis(chlorodimethylsilyl)benzene ((C6H4)(Me2SiCl)2) were used as organo-bridged bis(chlorosilane). Different types of silicophosphate oligomers with different network structures and terminal groups (P-OH and/or Si-Cl) were prepared by changing the reaction temperature and molar ratio of precursors. The formation of low molecular weight oligomers of ring and cage morphologies (ring tetramer, cage pentamer, and ring hexamer) is suggested in the product prepared from phosphoric acid and (C6H4)(Me2SiCl)2 molecule at 150 °C. Those silicophosphate hybrid oligomers are expected to be used as building blocks of hybrid materials with well-defined network structures for desired functionalities.

Thermal analysis and melt spinnability of poly(acrylonitrile-co-methyl acrylate) and poly(acrylonitrile-co-dimethyl itaconate) copolymers

2017 ◽  
Vol 88 (13) ◽  
pp. 1479-1490 ◽  
Author(s):  
Syang-Peng Rwei ◽  
Tun-Fun Way ◽  
Whe-Yi Chiang ◽  
Jen-Chun Tseng
Keyword(s):  
Thermal Analysis ◽  
Carbon Fiber ◽  
Low Temperature ◽  
Melting Temperature ◽  
Methyl Acrylate ◽  
Dwell Time ◽  
Molar Ratio ◽  
Poly Acrylonitrile ◽  
Feed Molar Ratio ◽  
Dimethyl Itaconate

This work investigated the cyclization possibility and melt spinnability of carbon fiber precursors, poly(acrylonitrile-co-methyl acrylate) (AN/MA) and poly(acrylonitrile-co-dimethyl itaconate) (AN/DMI). The onset temperature of cyclization of the AN/DMI copolymer is lower than that of the AN/MA copolymer and also the polyacrylonitrile (PAN) homopolymer. The enthalpy ( ΔH) of the AN/DMI copolymer is about 3–4 times that of the PAN homopolymer and about 1.8 times that of the AN/MA copolymer, indicating that the degree of cyclization of the AN/DMI copolymer is relatively higher. The melt dwell time of the AN/DMI copolymer is increased to about 3–5 times that of the AN/MA copolymer, especially when synthesized with a feed molar ratio of AN/DMI = 85/15. The AN/DMI copolymer (AN/DMI = 85/15) has the longest melt dwell time, 24.8 min, at the lowest melting temperature, 190oC, among all the PAN-related copolymers synthesized herein. Furthermore, the AN/DMI copolymer (AN/DMI = 85/15) can be rapidly cyclized at the cyclization temperature of 260℃, which is 25℃ lower than that of the AN/MA copolymer (AN/MA = 85/15). In short, this work demonstrates that the carbon fiber precursor made by the AN/DMI copolymer (AN/DMI = 85/15) will be superior to that of the AN/MA copolymer (AN/MA = 85/15) with respect to the melt spinnability and cyclization at low temperature.

New Methacrylate-Functionalized Ba and Ba−Ti Oxoclusters as Potential Nanosized Building Blocks for Inorganic−Organic Hybrid Materials:  Synthesis and Characterization

2007 ◽  
Vol 46 (9) ◽  
pp. 3459-3466 ◽  
Author(s):  
Alberto Albinati ◽  
Francesco Faccini ◽  
Silvia Gross ◽  
Guido Kickelbick ◽  
Silvia Rizzato ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Building Blocks ◽  
Synthesis And Characterization ◽  
Materials Synthesis ◽  
Organic Hybrid

scholarly journals Mesostructured ZnO/Au nanoparticle composites with enhanced photocatalytic activity

Polymer ◽  
2017 ◽  
Vol 128 ◽  
pp. 65-70 ◽  
Author(s):  
Carina Bojer ◽  
Judith Schöbel ◽  
Thomas Martin ◽  
Thomas Lunkenbein ◽  
Daniel R. Wagner ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Au Nanoparticle ◽  
Nanoparticle Composites

THERMAL INVESTIGATION OF SiO2-Bi2O3 HEAVY METAL GLASSES

2005 ◽  
Vol 19 (20) ◽  
pp. 3293-3299 ◽  
Author(s):  
V. SIMON ◽  
M. TODEA ◽  
S. SIMON
Keyword(s):  
Thermal Analysis ◽  
Heavy Metal ◽  
Differential Thermal Analysis ◽  
Silicon Dioxide ◽  
Melting Temperature ◽  
Structural Relaxation ◽  
Structural Changes ◽  
Glass Stability ◽  
Thermal Investigation ◽  
Metal Glasses

Structural changes induced by temperature rising in binary silico-bismuthate glasses are investigated by differential thermal analysis. Several exothermic peaks are recorded for all samples. Progressive substitution of Bi 2 O 3 by SiO 2 contributes to the structural relaxation of vitreous network and leads to diminishing of the melting temperature, even as SiO 2 content reaches 40 mol%. Glass stability is enhanced by addition of silicon dioxide.

scholarly journals Thermostable designed ankyrin repeat proteins (DARPins) as building blocks for innovative drugs

2021 ◽  
Author(s):  
Johannes Schilling ◽  
Christian Jost ◽  
Ioana Mariuca Ilie ◽  
Joachim Schnabl ◽  
Oralea Buechi ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Building Blocks ◽  
Ankyrin Repeat ◽  
Internal Repeat ◽  
Repeat Proteins ◽  
Repeat Domain ◽  
Ankyrin Repeat Proteins ◽  
Classical Immunoglobulin ◽  
Dynamics Simulations ◽  
Innovative Drugs

AbstractDesigned Ankyrin Repeat Proteins (DARPins) are a class of antibody mimetics with a high and mostly unexplored potential in drug development. They are clinically validated and thus represent a true alternative to classical immunoglobulin formats. In contrast to immunoglobulins, they are built from solenoid protein domains comprising an N-terminal capping repeat, one or more internal repeats and a C-terminal capping repeat. By using in silico analysis and a rationally guided Ala-Scan, we identified position 17 of the N-terminal capping repeat to play a key role for the overall protein thermostability. The melting temperature of a DARPin domain with a single full-consensus internal repeat was increased by about 8°C to 10°C when the original Asp17 was replaced by Leu, Val, Ile, Met, Ala or Thr, as shown by high-temperature unfolding experiments at equilibrium. We then transferred the Asp17Leu mutation to various backgrounds, including different N- and C-terminal capping repeats and clinically validated DARPin domains, such as the VEGF-binding ankyrin repeat domain of abicipar pegol. In all cases, the proteins remained monomeric and showed improvements in the thermostability of about 8°C to 16°C. Thus, the replacement of Asp17 seems to be generically applicable to this drug class. Molecular dynamics simulations show that the Asp17Leu mutation reduces electrostatic repulsion and improves van-der-Waals packing, rendering the DARPin domain less flexible and more stable. Interestingly, such a beneficial Asp17Leu mutation is present in the N-terminal caps of three of the five DARPin domains of ensovibep, a SARS-CoV-2 entry inhibitor currently in clinical development. This mutation is likely responsible, at least in part, for the very high melting temperature (>90°C) of this promising anti-Covid-19 drug. Overall, such N-terminal capping repeats with increased thermostability seem to be beneficial for the development of innovative drugs based on DARPins.

scholarly journals Effect of Mg/Al molar ratio on the basicity of Mg-Al mixed oxide derived from Mg-Al hydrotalcite

2020 ◽  
Vol 10 (6) ◽  
pp. 625
Author(s):  
Said Arhzaf ◽  
Mohammed Naciri Bennani ◽  
Sadik Abouarnadasse ◽  
Hamid Ziyat ◽  
Omar Qabaqous
Keyword(s):  
Thermal Analysis ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Molar Ratio ◽  
Acid Molecule ◽  
X Ray Diffraction ◽  
Phenol Adsorption ◽  
X Ray ◽  
Maximum Quantity ◽  
Uv Visible

<p>The fundamental character of the Mg-Al mixed oxide (Mg<sub>n</sub>(Al)O), derived from the Mg-Al hydrotalcite (Mg<sub>n</sub>Al-CO<sub>3</sub>-HT), where n corresponds to the Mg/Al molar ratio (n: 2, 2.5, 3, 3.5 and 4), was studied by using the adsorption of phenol as a probe acid molecule. The hydrotalcite precursors were prepared by the coprecipitation method. Their derived mixed oxides were obtained by thermal treatment at 450°C in a flow of air. The resulting solids were characterized by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric and differential thermal analysis             (TG-DTA), nitrogen physisorption (BET) and phenol chemisorption. The phenol adsorption followed by UV-Visible spectrophotometry shows that the basicity increases with the Mg/Al molar ratio, such that maximum quantity of phenol adsorbed (Q<sub>ads</sub> = 0.54 mmol/g <sub>cat</sub>) was obtained with the mixed oxide derived from the Mg-Al hydrotalcite of Mg/Al molar ratio equal to 3.5.</p>

scholarly journals Silver Cation Coordination Study to AsW9 Ligand – A Trilacunar Arsenotungstate Compound

2017 ◽  
Vol 63 (2) ◽  
pp. 70-72
Author(s):  
Lavinia Berta ◽  
Andrei Gâz ◽  
Francisc Boda ◽  
Augustin Curticapean
Keyword(s):  
Graphical Method ◽  
Ph Value ◽  
Building Blocks ◽  
Silver Cation ◽  
Molar Ratio ◽  
Equivalence Point ◽  
Tetrahedral Geometry ◽  
Sandwich Type ◽  
Preliminary Study ◽  
Cation Coordination

Abstract Objective: The main objective of this research is to find the coordination ratio between AsW9 and Ag+, as a preliminary study for synthesizing a new silver-arsenotungstate complex. Material and method: The ligand:cation molar ratio in complexes was determined by conductometric and potentiometric titrations of AsW9 with silver salts: CH3COOAg, AgNO3. Results: The ratio was obtained from the inflexion points of the curves when molar ratio was plotted versus conductivity, or from the equivalence point when silver added volume was plotted versus pH value. Each graphic shows one point of inflexion corresponding to 1:1.54 ratio of AsW9:Ag+. In the same manner, the equivalent volumes determined by graphical method gave the ratio 1:1.53. The spectral results confirmed that a AsW9:Ag+ complex was formed since the ligand absorption maxima values have been changed from 190 nm to 197 nm in the case of using AgNO3 and 196 nm for CH3COOAg corresponding to the W=Od bond, and from 246.5 nm to 274 nm (AgNO3) and 270 nm (CH3COO-Ag+) for the W-Ob,c-W bond. Conclusions: Silver cation exhibit a preference for AsW9 in a ratio of 3 to 2. This ratio can be associated to a sandwich type arrangement, with two trilacunary Keggin building blocks incorporating 3 metal cations in a tetrahedral geometry.

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