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UV irradiation-H2O2 system as an effective combined depolymerization technique to produce oligosaccharides from chitosan

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Bio-Design and Manufacturing 2018年第1期1卷 62-68页

作者： seyed ahmad ayati najafabadi Hengameh Honarkar Majid Moghadam Valiollah Mirkhani Mohammadreza Tahriri Lobat Tayebi Biomaterials Group Faculty of Biomedical Engineering Amirkabir University of Technology Tehran Iran Polyurethane and Advanced polymers Faculty of Science Iran Polymer and Petrochemical Institute Tehran Iran Catalysis Divisions Department of Chemistry University of Isfahan Isfahan Iran Marquette University School of Dentistry Milwaukee WI 53233 USA Department of Engineering Science University of Oxford Oxford OX13PJ UK

UV irradiation hydrogen peroxide （H202） system is used as an effective, easy and low-cost combined depolymerization technique to produce oligosaccharides from chitosan. UV-Vis spectroscopic studies explained that with increasing treatment time, the absorption of the depolymerized chitosan solution has increased, indicating the increase in the carbonyl and amino groups in their structure. Fourier transform infrared spectroscopy and nuclear magnetic resonance （1H NMR） analysis showed that the 1,4-β-D-glucoside linkages of chitosan are degraded without important changes in chemical structure of decomposed samples. X-ray diffraction patterns verified the polymerization of chitosan to produce oligomers, changing in structure from crystalline to amorphous. Viscosity-average molecular weight measurements of fragmented chitosan samples and MarkHouwink equation are used to demonstrate the efficiency of this depolymerization method. Finally, the obtained results ascertained that this combined method could produce water soluble chitosan with significant efficiency and no essential change in its chemical *** irradiation hydrogen peroxide （H202） system is used as an effective, easy and low-cost combined depolymerization technique to produce oligosaccharides from chitosan. UV-Vis spectroscopic studies explained that with increasing treatment time, the absorption of the depolymerized chitosan solution has increased, indicating the increase in the carbonyl and amino groups in their structure. Fourier transform infrared spectroscopy and nuclear magnetic resonance （1H NMR） analysis showed that the 1,4-β-D-glucoside linkages of chitosan are degraded without important changes in chemical structure of decomposed samples. X-ray diffraction patterns verified the polymerization of chitosan to produce oligomers, changing in structure from crystalline to amorphous. Viscosity-average molecular weight measurements of fragmented chitosan samples and MarkHouwink equation are used to dem

关键词： Chitosan Depolymerization Ultraviolet irradiation Hydrogen peroxide Oligosaccharides

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Ga-(Nb+Ta)-(Nb/Ta)(Zr/Hf) Ternary Diagram: An Excellent Tool for Discriminating Barren and Ta-Hosting Granite-Pegmatite Systems

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Journal of Earth Science 2020年第3期31卷 551-558页

作者： Maryam Mohamadizadeh seyed Hossein Mojtahedzadeh Farimah ayati Mining and Metallurgical Engineering Department Yazd UniversityYazd 98195-741Iran Department of Geology Payame Noor University19395-4697 TehranIran

Discriminating barren and fertile intrusions is one of the main challenges in the search for rare-element *** comprising more than one element can make discrimination of productive and barren samples more *** diagrams distinguish samples by simultaneous means of positive and/or negative correlations between variables.A ternary diagram for S-type peraluminous granites has been obtained in this ***,a database composed of Ta-bearing and barren granitic systems was created,then geochemical behavior of trace elements was studied,and statistical investigations were done using GCDkit software,which resulted in the Ga-(Nb+Ta)-(Nb/Ta)(Zr/Hf)ternary diagram which can distinguish the non-mineralized granites from productive *** Ta-bearing samples,which are situated in the fertile field in the diagram,are those which have high Nb and Ta contents,elevated Ga content and the lowest Nb/Ta and Zr/Hf values.

关键词： tantalum mineralization S-type peraluminous granite discrimination of fertile and barren granites whole-rock geochemistry indicators

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The use of Chinese herbal drugs in Islamic medicine

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Journal of Integrative Medicine 2015年第6期13卷 363-367页

作者： Mojtaba Heyadri Mohammad Hashem Hashempur Mohammad Hosein ayati Detlev Quintern Majid Nimrouzi seyed Hamdollah Mosavat Research Center for Traditional Medicine and History of Medicine Shiraz University of Medical Sciences Department of Traditional Persian Medicine School of MedicineShiraz University of Medical Sciences Department of Traditional Medicine Fasa University of Medical Sciences Noncommunicable Diseases Research Center Fasa University of Medical Sciences Department of Traditional Medicine School of Traditional MedicineTehran University of Medical Sciences Department of History of Science Fatih Sultan Mehmet Vakif University Essence of Parsiyan Wisdom Institute Traditional Medicine and Medicinal Plant IncubatorShiraz University of Medical Sciences

This paper investigates some of the ways that Chinese medicine has been transferred to the Western world and to Islamic territories. During the Golden Age of Islam （8th to 13th century CE）, the herbal drug trade promoted significant commercial and scientific exchange between China and the Muslim world. Chinese herbal drugs have been described by medieval Muslim medical scholars such as Tabari （870 CE）, Rhazes （925 CE）, Haly Abbas （982 CE）, Avicenna （1037 CE） and Jurjani （1137 CE）. The term al-sin （the Arabic word for China） is used 46 times in Avicenna＇s Canon of Medicine in reference to herbal drugs imported from China. Cinnamon （dar sini; ＂Chinese herb＂）, wild ginger （asaron）, rhubarb （rivand-e sini）, nutmeg （basbasa）, incense tree wood （ood）, cubeb （kababe） and sandalwood （sandal） were the most frequently mentioned Chinese herbs in Islamic medical books. There are also multiple similarities between the clinical uses of these herbs in both medical systems. It appears that Chinese herbal drugs were a major component of the exchange of goods and knowledge between China and the Islamic and later to the Western world amid this era.

关键词： history of medicine, Chinese medicine Islamic medicine herbal drugs Golden Age of Islam

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