scholarly journals Material Priority Engineered Metal-Polyphenol Networks: Mechanism And Platform For Multifunctionalities

2021 ◽  
Author(s):  
Xinxiu Cheng ◽  
Yaxin Zhu ◽  
Ruofei Lu ◽  
Xiaoqiang Zhang ◽  
Na Li ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Photoelectron Spectroscopy ◽  
Cellular Proliferation ◽  
Early Stage ◽  
Great Influence ◽  
Deposition Process ◽  
Repair Process ◽  
Molar Ratio ◽  
Future Design ◽  
Coating Formation

Abstract Engineering the surface of materials with desired multifunctionalities is an effective way to fight against multiple adverse factors during the tissue repair process. Recently, metal-polyphenol networks (MPNs) have gained increasing attention because of their rapid and simple deposition process onto various substrates (silicon, quartz, gold and polypropylene sheets, etc.). However, the coating mechanism has not been clarified, and multifunctionalized MPNs remain unexplored. Herein, the flavonoid polyphenol procyanidin (PC) was selected to form PC-MPN coatings with Fe3+, and assembly parameters, including pH, molar ratio between PC and Fe3+, and material priority during coating formation, were thoroughly evaluated. We found that the material priority (addition sequence of PC and Fe3+) had a great influence on the thickness of the formed PC-MPNs. Various surface techniques (e.g., ultraviolet-visible spectrophotometry, quartz crystal microbalance, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy) were used to investigate the formation mechanism of PC-MPNs, and PC-MPNs were further engineered for multifunctionalities (fastening cellular attachment in the early stage, promoting long-term cellular proliferation, antioxidation and antibacterial activity). We believe that these findings could further reveal the coating formation mechanism of MPNs and guide the future design of MPN coatings with multifunctionalities, thereby greatly broadening their application prospects, such as in sensors, environments, drug delivery, and tissue engineering.

scholarly journals A comprehensive study on the microstructure evolution and oxidation resistance of conventional and nanocrystalline MCrAlY coatings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farzin Ghadami ◽  
Alireza Sabour Rouh Aghdam ◽  
Soheil Ghadami
Keyword(s):  
Electron Microscope ◽  
Oxidation Resistance ◽  
Photoelectron Spectroscopy ◽  
Oxidation Behavior ◽  
Early Stage ◽  
Deposition Process ◽  
Nanocrystalline Powders ◽  
X Ray ◽  
Mcraly Coating ◽  
Mcraly Coatings

AbstractConventional and nanocrystalline MCrAlY coatings were applied by the high-velocity oxy-fuel (HVOF) deposition process. The ball-milling method was used to prepare the nanocrystalline MCrAlY powder feedstock. The microstructure examinations of the conventional and nanocrystalline powders and coatings were performed using X-ray diffraction (XRD), high-resolution field emission scanning electron microscope (FESEM) equipped with energy-dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). Williamson–Hall analyzing method was also used for estimation of the crystalline size and lattice strain of the as-milled powders and sprayed coatings. Owing to the investigation of the oxidation behavior, the freestanding coatings were subjected to isothermal and cyclic oxidation testing at 1000 and 1100 °C under static air. The results showed that the conventional as-sprayed MCrAlY coating had a parabolic behavior in the early stage and prolonged oxidation process. On the contrary, in the case of the nanocrystalline MCrAlY coating, the long-term oxidation behavior has deviated from parabolic to sub-parabolic rate law. Moreover, the results also exemplified that the nanocrystalline MCrAlY coating had a greater oxidation resistance following the creation of a continuous and slow-growing Al2O3 scale with a fine-grained structure. The nucleation and growth mechanisms of the oxides formed on the nanocrystalline coating have also been discussed in detail.

Preparation of Water-Resistance Plywood with UF Resin Modified by Emulsifiable Polyisocyanate

2010 ◽  
Vol 26-28 ◽  
pp. 1056-1060
Author(s):  
Li Bin Zhu ◽  
Bo Han ◽  
Ji You Gu ◽  
Yan Hua Zhang ◽  
Hai Yan Tan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Water Resistance ◽  
Urea Formaldehyde ◽  
Great Influence ◽  
Physical And Mechanical Properties ◽  
Formaldehyde Emission ◽  
Molar Ratio ◽  
Formaldehyde Resin ◽  
X Ray ◽  
Uf Resin

The purpose of the study was to manufacture water-resistance plywood with using UF resin modified by emulsifiable polyisocyanate. The emulsifiable polyisocyanate which contains plenty of hydrophilic segments and teminal isocyanate groups were synthesized by reaction between various kinds of polyether polyols and polymeric methane dipthenyl diisocyanate (pMDI). A type of composite adhesive was obtained from the mixture of emulsifiable polyisocyanate and urea formaldehyde resin. The process parameters, such as the molar ratio of –NCO and –OH, mass fraction of emulsifiable polyisocyanate in UF resin and accessory ingredient have a great influence on the composite adhesive. X-ray photoelectron spectroscopy (XPS) had been used to analyze the chemical structure of bonding interface. The results showed that the composite adhesive consisting of UF resin and emulsifiable polyisocyanate content of 7.5% and kaolin content of 1.5% was used in plywood with high physical and mechanical properties, water resistance and low formaldehyde emission.

scholarly journals Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalyst Support ◽  
Oxidation Potential ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Optimum Parameters ◽  
Reduction Of Co2 ◽  
Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

Acrolein produced from polyamines as one of the uraemic toxins

2003 ◽  
Vol 31 (2) ◽  
pp. 371-374 ◽  
Author(s):  
K. Sakata ◽  
K. Kashiwagi ◽  
S. Sharmin ◽  
S. Ueda ◽  
K. Igarashi
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Oxidase Activity ◽  
Culture Medium ◽  
Cellular Proliferation ◽  
Amine Oxidase ◽  
Early Stage ◽  
Chronic Glomerulonephritis ◽  
Toxic Compound ◽  
Amine Oxidase Activity

It is well known that the addition of spermine or spermidine to culture medium containing ruminant serum inhibits cellular proliferation. This effect is caused by the products of oxidation of polyamines that are generated by serum amine oxidase. Among the products, we found that acrolein is a major toxic compound produced from spermine and spermidine by amine oxidase. We then analysed the level of polyamines (putrescine, spermidine and spermine) and amine oxidase activity in plasma of patients with chronic renal failure. It was found that the levels of putrescine and the amine oxidase activity were increased, whereas spermidine and spermine were decreased in plasma of patients with chronic renal failure. The levels of free and protein-conjugated acrolein were also increased in plasma of patients with chronic renal failure. An increase in putrescine, amine oxidase and acrolein in plasma was observed in all cases such as diabetic nephropathy, chronic glomerulonephritis and nephrosclerosis. These results suggest that acrolein is produced during the early stage of nephritis through kidney damage and also during uraemia through accumulation of polyamines in blood due to the decrease in their excretion into urine.

Low-temperature route to nanoscale P3N5 hollow spheres

2003 ◽  
Vol 18 (10) ◽  
pp. 2359-2363 ◽  
Author(s):  
Hongzhou Gu ◽  
Yunle Gu ◽  
Zhefeng Li ◽  
Yongcheng Ying ◽  
Yitai Qian
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hollow Spheres ◽  
Molar Ratio ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Influence Of Temperature On ◽  
Wide Gap ◽  
20 Nm ◽  
High Degree

Nanoscale hollow spheres of amorphous phosphorus nitride (P3N5) were synthesized by reacting PCl3 with NaN3 at 150–250 °C. Transmission electron microscope images show that the hollow spheres have a diameter of 150–350 nm, and the thickness of the shell is 20 nm. A very small amount of curly films were also found in the sample prepared at 150 °C. The infrared spectrum indicates a high degree of purity. X-ray photoelectron spectroscopy indicates the presence of P and N, with a molar ratio of 1:1.62 for P:N. Ultraviolet-visible absorption spectroscopy shows an absorption band at 265–315 nm. Under photoluminescent excitation at 230 nm, the P3N5 emits ultraviolet light at 305 nm. With a band gap of 4.28 eV, the products may be a wide gap semiconductor. A possible mechanism and the influence of temperature on the formation of the hollow spheres are also discussed.

Formation of GaN Self-Organized Nanotips by Nanomasking Effect

2001 ◽  
Vol 707 ◽  
Author(s):  
Harumasa Yoshida ◽  
Tatsuhiro Urushido ◽  
Hideto Miyake ◽  
Kazumasa Hiramtsu
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Aspect Ratio ◽  
Formation Mechanism ◽  
High Aspect Ratio ◽  
Photoelectron Spectroscopy ◽  
Nanometer Scale ◽  
Xps Analysis ◽  
X Ray ◽  
Self Organized

ABSTRACTWe have successfully fabricated self-organized GaN nanotips by reactive ion etching using chlorine plasma, and have revealed the formation mechanism. Nanotips with a high density and a high aspect ratio have been formed after the etching. We deduce from X-ray photoelectron spectroscopy (XPS) analysis that the nanotip formation is attributed to nanometer-scale masks of SiO2 on GaN. The structures calculated by Monte Carlo simulation of our formation mechanism are very similar to the experimental nanotip structures.

One-pot synthesis of double silane-functionalized carbon dots with tunable emission and excellent coating properties for WLEDs application

2021 ◽  
Author(s):  
Wenbing Cao ◽  
Yuhan Wu ◽  
Xin Li ◽  
Xuanfeng Jiang ◽  
Yuhong Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Great Influence ◽  
Alkoxy Group ◽  
Color Temperature ◽  
Molar Ratio ◽  
Coating Properties ◽  
One Pot ◽  
Light Emitting ◽  
Light Emitting Devices

Abstract Silane-functionalized carbon dots (SiCDs) can be exploited as effective color converting materials for the solid-state light-emitting devices. However, most of SiCDs reported thus far have shown photoluminescence emissions in the blue and green spectral range, which limit them to construct an efficient white light-emitting diodes (WLEDs) due to the lack of long-wavelength emission. Herein, a series of double silane-functionalized carbon dots (DSiCDs) were prepared via a one-step solvothermal method. The results show that the organic functional group of the silane has great influence on the optical properties of DSiCDs and the number of alkoxy group in the silane has great influence on coating properties of DSiCDs. In addition, the DSiCDs prepared by (3-aminopropyl)triethoxysilane and N-[3-(Trimethoxysilyl)propyl]ethylenediamine with molar ratio of 7:3 show excellent optical properties with the maximum emission at 608 nm under 400 nm excitation. Furthermore, they can be completely dried within 1 h at room temperature to form fluorescent coating with high stability and strong adhesion to the substrate. Together with their excellent optical and coating properties, they can be directly coated on LED chips to prepare WLEDs, with a CIE coordinate of (0.33,0.31), color rendering index of 81.6, and color temperature of 5774 K.

Characterization of Biomaterial and Tissue Response Analysis after Implantation

2018 ◽  
Vol 930 ◽  
pp. 48-52
Author(s):  
Eliana dos Santos Câmara-Pereira ◽  
Ana Emília Holanda Rolim ◽  
Isabela Cerqueira Barreto ◽  
Laise Monteiro Campos Moraes ◽  
Lilian Campos ◽  
...  
Keyword(s):  
Repair Process ◽  
Tissue Response ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Osteogenic Potential ◽  
Response Analysis ◽  
Defect Site ◽  
Critical Defect ◽  
Defect Repair

Some biomaterials can be used to promote tissue repair process. The biological substitutes (biomaterials such as hydroxyapatite beads) can be used with some advantages and purpose of mimicking responses to on-site repair of the injured bone. The objective of this study was to evaluate the osteogenic potential of the biomaterial composed of hydroxyapatite and alginate in place of the critical defect. bioceramic samples stoichiometric hydroxyapatite was produced by the precipitation method, wet method with ion molar ratio of Ca 10 (PO 4) 6 (OH) 2, in which the Ca / P ratio was equal to 1.67. The reaction conditions were favorable to the composition of a biomaterial with crystalline phase. The synthesis of the biomaterial composed of hydroxyapatite and alginate microspheres (HAAlg5%; 200 ø 425mm) was obtained from two primary solutions with the aim of, in optimal reactive conditions, to form the precipitate. After synthesis the microspheres were implanted into the defect site. The potential effects of using HAAlg5% and the application of vibratory waves in the critical defect repair were unknown and the results described in this study are promising, considering the systemic therapy and at the site of injury. The biomaterial used promoted repair the injured tissue.

scholarly journals Antisettici e controllo della carica batterica nelle ulcere venose/Antiseptics and control of bacterial load in venous ulcers

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Giuseppe Nebbioso ◽  
Ciro Falasconi ◽  
Viviana Nebbioso ◽  
Francesco Petrella
Keyword(s):  
Tissue Repair ◽  
Chronic Wound ◽  
Early Stage ◽  
Bacterial Load ◽  
Repair Process ◽  
Local Infection ◽  
Bacterial Burden ◽  
Venous Ulcers ◽  
Systemic Antibiotic Therapy ◽  
And Control

L’insorgenza di infezione su una lesione cutanea cronica determina un arresto del processo di riparazione tessutale e impone l’instaurazione di una terapia antibiotica sistemica che, in una fase iniziale, sarà empirica e, dunque, non scevra di insuccessi. L’utilizzo di antimicrobici con ridotto potere citotossoco/istiolesivo può essere considerata, in molti casi, una valida alternativa per il controllo della carica batterica e dell’infezione locale. L’associazione di antimicrobici a base di poliesanide biguanide, betaina e cadexomero iodico, in molti casi, permette di controllare/ridurre la carica batterica e l’infezione locale fungendo da starter per la ripresa del processo di riparazione tessutale. The onset of infection on a skin ulcer (chronic wound) leads to a halt in the tissue repair process and requires a systemic antibiotic therapy which, at an early stage, will be empirical and, therefore, not free from setbacks. The use of antimicrobials with reduced cytotoxic/histiolesive power can be considered, in many cases, a valid alternative for bacterial burden and local infection control. The combination of antimicrobials based on polystyrene biguanide, betaine and iodine cadexomer, in many cases, allows to control/reduce the bacterial burden and local infection by acting as a starter for the resumption of the tissue repair process.

scholarly journals Increased 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and cholesterol biosynthesis in freshly isolated hairy cell leukemia cells

Blood ◽  
1984 ◽  
Vol 63 (3) ◽  
pp. 690-693 ◽  
Author(s):  
S Yachnin ◽  
V Mannickarottu
Keyword(s):  
Peripheral Blood ◽  
Hairy Cell Leukemia ◽  
Cellular Proliferation ◽  
Coenzyme A ◽  
Cholesterol Biosynthesis ◽  
Clinical Manifestations ◽  
Molar Ratio ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Coenzyme A Reductase

Abstract Freshly isolated hairy cells from the peripheral blood of patients with hairy cell leukemia (HCL) synthesize 3–5-fold greater amounts of cholesterol, lanosterol, and squalene from [1–14C]-acetate than do normal human peripheral blood mononuclear cells under basal conditions of culture (i.e., in the presence of low-density lipoprotein). HCL cells also exhibit an eightfold increase in the activity of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase. These changes cannot be ascribed to increased rates of cellular proliferation in the HCL cells, nor are they a consequence of an increased rate of loss of newly synthesized cholesterol into the culture medium. The increased rate of cholesterol biosynthesis in HCL cells may result in an increase in their total cellular cholesterol content, as well as in an increase in their plasma membrane cholesterol:phospholipid molar ratio. These changes, in turn, are probably responsible for some of the clinical manifestations of this disease.

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