scholarly journals Rapid Benzylation of Wood Powder without Heating

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1118
Author(s):  
Mitsuru Abe ◽  
Masako Seki ◽  
Tsunehisa Miki ◽  
Masakazu Nishida
Keyword(s):  
Alkaline Treatment ◽  
Thermomechanical Analysis ◽  
Common Method ◽  
Similar Degree ◽  
Hydroxyl Groups ◽  
Wood Powder ◽  
Alkali Pretreatment ◽  
Long Time ◽  
Naoh Solution ◽  
The Common

Converting wood waste into thermoplastic materials is an attractive means of increasing its utilization. A promising method for imparting thermoplasticity to wood is chemical modification, in which the hydroxyl groups in wood are substituted with benzyl groups. In the common method, wood powder is first treated with a highly concentrated aqueous NaOH solution, and then reacted with a benzylation reagent by heating for a long time under stirring. In this study, a 50% aqueous tetra-n-butylphosphonium hydroxide solution was used for the pretreatment of wood powder. This modified alkaline treatment enhanced the efficiency of the subsequent benzylation reaction, which could be conducted without heating over a shorter time. The effects of various conditions on the efficiency of the benzylation reaction were evaluated. Both the alkali pretreatment and the subsequent benzylation required only ~5–10 min of stirring without heating to obtain benzylated wood with a similar degree of benzylation as that achieved by the common method. The chemical structure of the benzylated wood powder was characterized by Fourier-transform infrared and solid-state NMR spectroscopies, and its thermal softening characteristics were evaluated by thermomechanical analysis. Finally, a translucent film could be obtained by hot-pressing the benzylated wood powder.

The Research of Ship’s Electric Fields Characteristic wih Different Number of Compensatory Anode

2012 ◽  
Vol 622-623 ◽  
pp. 1912-1916
Author(s):  
Qiang Bian ◽  
Yi Liu ◽  
Liang Fen Xiao
Keyword(s):  
Mathematical Model ◽  
Electric Fields ◽  
Common Method ◽  
Long Time ◽  
The Common ◽  
A Current

For ensuring the life and security of ship, electric fields protection has been used for a long time. The common method of electric fields protection is equipping compensatory anode on the ship and adding a current which can been controlled to it. The electric fields is different when the number of compensatory anode is different. This paper establish a mathematical model of a ship with compensatory, and then analyze the ship’s electric fields when the number of compensatory anode is different. and attain how compensatory anode number affect ship’s electric fields protection.

HEALTHCARE CHALLENGES IN GILGIT BALTISTAN: THE WAY FORWARD

1970 ◽  
Vol 7 (2) ◽  
pp. 113-116
Author(s):  
Amimah Fatima Asif
Keyword(s):  
Health Care ◽  
Healthcare Delivery ◽  
Medical Personnel ◽  
Political Regime ◽  
Quality Healthcare ◽  
Accident And Emergency ◽  
Long Time ◽  
The Common ◽  
Gilgit Baltistan ◽  
And Child Health

Quality healthcare delivery is the bedrock to exponentially accelerate the development of a country. Unfortunately, in Pakistan healthcare has been neglected since a long time, with the common man bearing the brunt of this acute situation. There are critical challenges in health care, with paucity of trained human resource and deficit of regulated infrastructure and service delivery being the predominant dilemmas. Primary and secondary healthcare are in an unseemly state, to say the least. Maternal and child health care, accident, and emergency departments and mental health are among the most undermined and forsaken areas of healthcare, primarily in the far flung Gilgit Baltistan region of Pakistan. The only way forward is if the political regime, administration and the medical personnel work in concurrence to revise the health infrastructure of the country.

The Application of the Cold Atmospheric Plasma-Activated Solutions in Cancer Treatment

2018 ◽  
Vol 18 (6) ◽  
pp. 769-775 ◽  
Author(s):  
Dayun Yan ◽  
Jonathan H. Sherman ◽  
Michael Keidar
Keyword(s):  
Cancer Treatment ◽  
Atmospheric Plasma ◽  
Current Status ◽  
Cold Atmospheric Plasma ◽  
Anti Cancer ◽  
Long Time ◽  
Key Topics ◽  
The Common

Background: Over the past five years, the cold atmospheric plasma-activated solutions (PAS) have shown their promissing application in cancer treatment. Similar as the common direct cold plasma treatment, PAS shows a selective anti-cancer capacity in vitro and in vivo. However, different from the direct cold atmospheric plasma (CAP) treatment, PAS can be stored for a long time and can be used without dependence on a CAP device. The research on PAS is gradually becoming a hot topic in plasma medicine. Objectives: In this review, we gave a concise but comprehensive summary on key topics about PAS including the development, current status, as well as the main conclusions about the anti-cancer mechanism achieved in past years. The approaches to make strong and stable PAS are also summarized.

scholarly journals Preparation and Antimicrobial Activity of Chitosan and Its Derivatives: A Concise Review

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3694
Author(s):  
Luminita Georgeta Confederat ◽  
Cristina Gabriela Tuchilus ◽  
Maria Dragan ◽  
Mousa Sha’at ◽  
Oana Maria Dragostin
Keyword(s):  
Antimicrobial Activity ◽  
Low Cost ◽  
Hydroxyl Groups ◽  
Pharmacological Properties ◽  
Natural Polymers ◽  
Economic Sectors ◽  
Physico Chemical ◽  
Long Time ◽  
Resistant Strains ◽  
Strength And Durability

Despite the advantages presented by synthetic polymers such as strength and durability, the lack of biodegradability associated with the persistence in the environment for a long time turned the attention of researchers to natural polymers. Being biodegradable, biopolymers proved to be extremely beneficial to the environment. At present, they represent an important class of materials with applications in all economic sectors, but also in medicine. They find applications as absorbers, cosmetics, controlled drug delivery, tissue engineering, etc. Chitosan is one of the natural polymers which raised a strong interest for researchers due to some exceptional properties such as biodegradability, biocompatibility, nontoxicity, non-antigenicity, low-cost and numerous pharmacological properties as antimicrobial, antitumor, antioxidant, antidiabetic, immunoenhancing. In addition to this, the free amino and hydroxyl groups make it susceptible to a series of structural modulations, obtaining some derivatives with different biomedical applications. This review approaches the physico-chemical and pharmacological properties of chitosan and its derivatives, focusing on the antimicrobial potential including mechanism of action, factors that influence the antimicrobial activity and the activity against resistant strains, topics of great interest in the context of the concern raised by the available therapeutic options for infections, especially with resistant strains.

Latins and Greeks in Debate over Purgatory, 1230–1439

1984 ◽  
Vol 35 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Robert Ombres
Keyword(s):  
Thirteenth Century ◽  
Long Time ◽  
The Subject ◽  
The Common ◽  
Common Agenda

By the 1230s Latins and Greeks were riot short of issues for debate or polemic, but the topic of purgatory did have a novel feel about it. The doctrine seems to emerge on the common agenda fairly suddenly, finding no place, for example, in the wide-ranging list of 104 points of divergence drawn up by the Byzantine prelate, Constantine Stilbès, in the wake of the cruel sack of Constantinople by the Latins in 1204. The subject did, however, establish itself as a hardy perennial, and it is proposed to trace its main ramifications up to the death of Emperor Michael viii in 1282, and then to concentrate on the Council of Ferrara–Florence (1438–9). Without a doubt the debates and the constant attempts at reunion were not conducted in isolation from wider cultural, political and military considerations, the kind of considerations that in 1400 would lead the Byzantine emperor to journey as far as England. But here the emphasis will fall on the theological aspects. Moreover, there were also in play forces of inertia, ignorance and mutual incomprehension difficult to assess rationally. The thirteenth-century friar, Humbert of Romans O.P., in discussing what would make for reunion with the Greeks noted how a schism might be continued simply because it had existed for a long time, just like the feud between Guelf and Ghibelline.

Controlled Release of Active Substance from Biodegradable Copolymer Matrix

2006 ◽  
Vol 510-511 ◽  
pp. 798-801
Author(s):  
Hyung Suk So ◽  
Hyun Chul Shin ◽  
Beom Suk Kim ◽  
Yeong Seok Yoo
Keyword(s):  
Methylene Blue ◽  
Active Substance ◽  
Phosphate Buffer Solution ◽  
Ultra Violet ◽  
Hydroxyl Groups ◽  
Buffer Solution ◽  
Solution Ph ◽  
Effective Discharge ◽  
Constant Rate ◽  
Long Time

The purpose of this study is to develop a new system to control effective discharge of active substances such as agricultural chemicals. To synthesize a naturally dissolvable polymer; ε-caprolactone and diglycolide were copolymerized with ethylene glycol as an initiator to produce macrodiol. As macrodiol has hydroxyl groups in both ends, they are modified with methacryloyl chloride for photochemical networking. After standard macromonomer produced by this procedure was physically mixed with methylene blue, it was networked with ultra-violet rays to be filmed. This film is naturally dissolvable and hydrolytic. As a result of hydrolytic test with a crosslinked structure of 10 % methylene blue, it decreased by 9 % for seven weeks in 37 °C phosphate buffer solution (pH = 7). Thus, we verified that active substance can be discharged from a crosslinked structure for a long time at a constant rate under room temperature.

scholarly journals Alkali treatment of fungal pretreated wheat straw for bioethanol production

Bioethanol ◽  
2016 ◽  
Vol 2 (1) ◽  
Author(s):  
María García-Torreiro ◽  
Miguel Álvarez Pallín ◽  
María López-Abelairas ◽  
Thelmo A. Lu-Chau ◽  
Juan M. Lema
Keyword(s):  
Wheat Straw ◽  
Alkali Treatment ◽  
Alkaline Treatment ◽  
White Rot ◽  
White Rot Fungus ◽  
Process Conditions ◽  
Alkali Pretreatment ◽  
Irpex Lacteus ◽  
C 30 ◽  
Pretreated Wheat Straw

AbstractBioconversion of lignocellulosic materials into ethanol requires an intermediate pretreatment step for conditioning biomass. Sugar yields from wheat straw were previously improved by the addition of a mild alkali pretreatment step before bioconversion by the white-rot fungus Irpex lacteus. In this work, an alternative alkaline treatment, which significantly reduces water consumption, was implemented and optimized. Sugar recovery increased 117% with respect to the previously developed alkaline wash process at optimal process conditions (30°C, 30 minutes and 35.7% (w/w) of NaOH). In order to further reduce operational costs, a system for alkali recycling was implemented. This resulted in the treatment of 150% more wheat straw using the same amount of NaOH. Finally, enzymatic hydrolysis was optimized and resulted in a reduction of enzyme dose of 33%.

Formability of Hydroxyapatite on Beta-Type Ti-Nb-Ta-Zr Alloy for Biomedical Applications through Alkaline Treatment Process

2007 ◽  
Vol 352 ◽  
pp. 297-300
Author(s):  
Toshikazu Akahori ◽  
Mitsuo Niinomi ◽  
Masaaki Nakai
Keyword(s):  
Alkaline Solution ◽  
Biomedical Applications ◽  
Treatment Process ◽  
Solution Treatment ◽  
Sodium Titanate ◽  
Alkaline Treatment ◽  
Simple Method ◽  
Metallic Biomaterials ◽  
Naoh Solution ◽  
Bioactive Surface Modification

Titanium and its alloys have been widely used as biomaterials for hard tissue replacements because of their excellent mechanical properties and biocompatibility. However, the bonding between their surfaces and bone is not enough after implantation. The bioactive surface modification such as a hydroxyapatite (HAp) coating on their surfaces has been investigated. Recently, a simple method for forming HAp layer on the surfaces of titanium and its alloys has been developed. This method is called as alkaline treatment process. In this method, HAp deposits on the surfaces of titanium and its alloys by dipping into simulated body fluid (SBF) after an alkaline solution treatment that is followed by a baking treatment (alkaline treatment). This process is applicable to newly developed beta-type Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) for biomedical applications achieving bioactive HAp modification. In this study, the morphology of the HAp layer formed on the surface of TNTZ was investigated after various alkaline treatments followed by dipping in SBF. The formability of HAp on the surface of TNTZ was then discussed. The formability of HAp on TNTZ is much lower than that of commercially pure Ti, Ti-6Al-4V ELI and Ti-15Mo-5Zr-3Al alloys, which are representative metallic biomaterials. The formability of HAp on TNTZ is improved by increasing the amount of Na in the sodium titanate gels formed during an alkaline solution treatment where the NaOH concentrations and the dipping time are over 5 M and 172.8 ks, respectively. The formability of HAp on TNTZ is considerably improved by dipping in a 5 M NaOH solution for 172.8 ks. This condition for alkaline solution treatment process is the most suitable for TNTZ.

Sign in / Sign up

Export Citation Format

Share Document