The effect of polyvinyl alcohol and polyvinyl pyrrolidone on diffusion artifacts in lactate dehydrogenase histochemistry

Histochemie ◽  
1970 ◽  
Vol 24 (4) ◽  
pp. 354-370 ◽  
Author(s):  
Hans A. Dahl ◽  
Svein Ivar Mellgren
2018 ◽  
Vol 15 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Preeti B. Hammannavar ◽  
Blaise Lobo

Films of polyvinyl alcohol (PVA) – polyvinyl pyrrolidone (PVP) blend doped with lead nitrate (Pb(NO3)2) were prepared by solution casting method, with doping level (DL) of Pb(NO3)2 in PVA – PVP polymeric blend varying from 2.7 up to 50.5 wt%. The prepared films were characterized using UV-Visible spectroscopy, fluorescence (or photo- luminescence) spectroscopy, FTIR and Raman spectroscopy. Parameters like optical band gaps due to indirect allowed transition (IAT) and direct allowed transition (DAT), as well as the activation energy (Ea) for optical transitions are extracted from the UV- Visible (or optical) spectra of these films. Objective of the FTIR, Raman and Fluorescence spectroscopic study is to understand the molecular chemical changes in PVA and PVP caused by the dopant (Pb(NO3)2). There is an enhancement of fluorescence intensity at DLs of 2.7 wt%, and at DL 7.6 wt%, the fluorescence intensity decreases (quenching). PVP acts as a capping agent for the dopant species, and is considered to be responsible for changes in fluorescence intensity. Signature of nitrate ion (NO3-) vibration is observed at wavenumber 1037 cm-1 in Raman spectra, and in the FTIR spectra, the NO3- vibration is seen at the wavenumber equal to 1380 cm-1.


2021 ◽  
Vol 29 (2) ◽  
Author(s):  
Norhashidah , Talip ◽  
Amalina Muhammad Afifi ◽  
Mohd Yusof Hamzah ◽  
Maznah Mahmud ◽  
Sarada Idris

Chitosan/Polyvinyl alcohol (CS/PVA) films were coated with layer of polyvinyl pyrrolidone (PVP) to improve its mechanical strength. In this study, chitosan/PVA mixture was first cast into film. The films were later dipped into different concentrations of PVP solutions at 1%, 3%, and 5%. They were then exposed to gamma (γ) radiation at 5,10,20 and 30 kGy. The tensile strength of chitosan/PVA films coated with 1% PVP was found to increase up to 31%. Elongation at break was improved by 1% PVP coating. The CS/PVA Removal Efficiency (RE) with or without PVP coatings were not affected by γ irradiation. Result shows that the best settings to enhance the tensile strength of CS/PVA films for Cu adsorption application was 1% PVP coating at 5 kGy γ radiation.


Ionics ◽  
2017 ◽  
Vol 23 (7) ◽  
pp. 1771-1781 ◽  
Author(s):  
Mangalam Ramaswamy ◽  
Thamilselvan Malayandi ◽  
Selvasekarapandian Subramanian ◽  
Jayakumar Srinivasalu ◽  
Manjuladevi Rangaswamy

2001 ◽  
Vol 62 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Mirzan T Razzak ◽  
Darmawan Darwis ◽  
Zainuddin ◽  
Sukirno

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