scholarly journals Determination of the light exposure on the photodiodes of a new instrumented baffle for the Virgo input mode cleaner end-mirror

2020 ◽  
Vol 38 (4) ◽  
pp. 045002
Author(s):  
A Romero-Rodríguez ◽  
A Allocca ◽  
A Chiummo ◽  
M Martínez ◽  
Ll M Mir ◽  
...  
Keyword(s):  
Light Exposure ◽  
Input Mode

scholarly journals Determination of Dental Adhesive Composition throughout Solvent Drying and Polymerization Using ATR–FTIR Spectroscopy

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3886
Author(s):  
Arwa Almusa ◽  
António H.S. Delgado ◽  
Paul Ashley ◽  
Anne M. Young
Keyword(s):  
Light Exposure ◽  
Light Emitting Diode ◽  
Attenuated Total Reflectance ◽  
Drying Time ◽  
Light Emitting ◽  
Spectral Changes ◽  
One Step ◽  
Urethane Dimethacrylate ◽  
Kinetics Of

The of this study aim was to develop a rapid method to determine the chemical composition, solvent evaporation rates, and polymerization kinetics of dental adhesives. Single-component, acetone-containing adhesives One-Step (OS; Bisco, USA), Optibond Universal (OU; Kerr, USA), and G-Bond (GB; GC, Japan) were studied. Filler levels were determined gravimetrically. Monomers and solvents were quantified by comparing their pure Attenuated Total Reflectance-Fourier Transform Infra-Red (ATR–FTIR) spectra, summed in different ratios, with those of the adhesives. Spectral changes at 37 °C, throughout passive evaporation for 5 min, then polymerisation initiated by 20 s, and blue light emitting diode (LED) (600 mW/cm2) exposure (n = 3) were determined. Evaporation and polymerisation extent versus time and final changes were calculated using acetone (1360 cm−1) and methacrylate (1320 cm−1) peaks. OS, OU, and GB filler contents were 0, 9.6, and 5.3%. FTIR suggested OS and OU were Bis-GMA based, GB was urethane dimethacrylate (UDMA) based, and that each had a different diluent and acidic monomers and possible UDMA/acetone interactions. Furthermore, initial acetone percentages were all 40−50%. After 5 min drying, they were 0% for OS and OU but 10% for GB. Whilst OS had no water, that in OU declined from 18 to 10% and in GB from 25 to 20% upon drying. Evaporation extents were 50% of final levels at 23, 25, and 113 s for OS, OU, and GB, respectively. Polymerisation extents were all 50 and 80% of final levels before 10 and at 20 s of light exposure, respectively. Final monomer polymerisation levels were 68, 69, and 88% for OS, OU, and GB, respectively. An appreciation of initial and final adhesive chemistry is important for understanding the properties. The rates of evaporation and polymerisation provide indications of relative required drying and light cure times. UDMA/acetone interactions might explain the considerably greater drying time of GB.

scholarly journals Simultane ous Determination of Protopseudohypericin, Pseudohypericin, Protohypericin, and Hypericin Without Light Exposure

2005 ◽  
Vol 88 (6) ◽  
pp. 1607-1612 ◽  
Author(s):  
Steven F Baugh
Keyword(s):  
Free Radical ◽  
Light Exposure ◽  
Radical Reactions ◽  
Mathematical Relationship ◽  
Free Radical Reactions ◽  
St John's Wort ◽  
Naturally Occurring ◽  
Analytical Response ◽  
Marker Compounds

Abstract St. John's wort products are commonly standardized to total naphthodianthrones and hyperforin. Determination of these marker compounds is complicated because of the photochemistry of the naphthodianthrones pseudohypericin and hypericin and the instability of hyperforin in solution. Protopseudohypericin and protohypericin have been identified as naturally occurring naphthodianthrones and, when exposed to light, they are converted into pseudohypericin and hypericin, respectively. However, exposure to light and the resulting naphthodianthrone free-radical reactions oxidize hyperforin. A mathematical relationship between the response of the proto compound and the resulting naphthodianthrone can be established by comparing the analytical response of the proto compound in a solution protected from light with the increase in the analytical response of naphthodianthrone in the same solution after exposure to light. By mathematically converting the proto compounds to their respective products, exposure to light can be avoided while still including proto compounds in a single assay. The method presented here details the reporting of all significant naphthodianthrones, including protopseudohypericin and protohypericin, without exposure to light. This approach includes the benefits of improved naphthodianthrone precision and protection of hyperforin from oxidation.

scholarly journals THE FORMULATION OF DRY CURCUMA (CURCUMA XANTHORRHIZA ROXB.) EXTRACT MICROCAPSULES BY SPRAY WET MICROENCAPSULATION TECHNIQUES

2018 ◽  
Vol 11 (3) ◽  
pp. 226
Author(s):  
Samran Samran ◽  
Dalimunthe Dalimunthe ◽  
Dalimunthe Dalimunthe ◽  
Dalimunthe Dalimunthe
Keyword(s):  
Sodium Alginate ◽  
Brown Algae ◽  
Raw Materials ◽  
Light Exposure ◽  
Gastrointestinal Disease ◽  
Dry Weight ◽  
Compressibility Index ◽  
Curcuma Xanthorrhiza

 Objective: Curcuma xanthorrhiza Roxb. was used as hereditary medicinal plant for prevention of liver dysfunction, gastrointestinal disease, fever, and hemorrhoid. Curcuma extract was easy to damage because the light exposure, change of pH, weather and a long period of storage time. The problem can be solved by coating the extract with spray wet microencapsulation (SWM) technique. SWM technique is a method of preparing microcapsules in which a solution, suspension, or emulsion with a charged matrix is sprayed into opposing solution. The aim of this research was to formulate the dry Curcuma extract with SWM technique using sodium alginate as matrix.Methods: Brown algae (Sargassum ilicifolium) was a main resource of alginate acid. It was isolated using HCl 5% to make alginate acid and sodium alginate that was obtained by adding Na2CO3 5% to alginate acid solution. The microencapsulation process of Curcuma extract was done by SWM technique. The formula of Curcuma extract microencapsulation was design into three formulas: F1, F2, and F3. Microcapsules of Curcuma extract were being characterized for color intensity, analysis of scanning electron microscope (SEM), compressibility index, flowing time, and determination of angle repose.Results: The results showed that the higher concentration of sodium alginate used, the dry Curcuma extract microcapsules produced better. Particle size of extract microcapsules of Curcuma extract microcapsules SEM from F1, F2, F3 was 20 μm whereas dry weight of extracted microcapsule of Curcuma grows with increasing concentration of sodium alginate: F1 (0.2%) 19.86±0.11 g, F2 (0.4%) 20.66±0.73, F3 (0.6%) 21.29±0.64. The flowing time of F1, F2, and F3 was 6.92±0.56, 7.42±0.50, and 8.05±0.54 s consecutively.Conclusions: Based on the analysis of the study result, it can be concluded that the raw materials of Curcuma extract can be made by SWM technique using sodium alginate isolated from brown algae, and the characterization of dry Curcuma extract microcapsule of the three formulas met the requirements of the pre-formulation tests for capsule dosage form.

Condition Determination of Ultraviolet Light Exposure for High-throughput Nanoimprinting

2016 ◽  
Vol 45 (12) ◽  
pp. 1373-1375 ◽  
Author(s):  
Yota Ishito ◽  
Haruna Yano ◽  
Nobuya Hiroshiba ◽  
Shoichi Kubo ◽  
Masaru Nakagawa
Keyword(s):  
Ultraviolet Light ◽  
High Throughput ◽  
Light Exposure

Quantitative determination of the reduction of phototoxicity and photobleaching by controlled light exposure microscopy

2008 ◽  
Vol 231 (1) ◽  
pp. 9-20 ◽  
Author(s):  
R.A. HOEBE ◽  
H.T.M. VAN DER VOORT ◽  
J. STAP ◽  
C.J.F. VAN NOORDEN ◽  
E.M.M. MANDERS
Keyword(s):  
Quantitative Determination ◽  
Light Exposure

scholarly journals POTENSI PRODUKSI BIOFUEL DARI BIOMASSA FITOPLANKTON LAUT SPESIES Chlorella vulgaris, Dunaliella salina DAN Spirulina sp., YANG DITUMBUHKAN DALAM NUTRIEN UNGGUL “MSSIP” TERINDUKSI ION LOGAM Fe, Co, DAN Ni

KOVALEN ◽  
2017 ◽  
Vol 3 (1) ◽  
pp. 89
Author(s):  
Syahruddin Kasim ◽  
Paulina Taba ◽  
Indah Raya ◽  
Ruslan Ruslan
Keyword(s):  
Metal Ions ◽  
Chlorella Vulgaris ◽  
Mass Culture ◽  
Phytoplankton Biomass ◽  
Dunaliella Salina ◽  
Growth Parameters ◽  
Raw Materials ◽  
Light Exposure ◽  
Initial Density

Research about composition of superior nutrients, growth parameters, and best method to maximize production of biomass sea phytoplankton, Chlorella  vulgaris, Dunaliella salina, and Spirulina sp. has been performed. The nutrients was named as MSSIP which were consist of following compositions: urea fertilizer, Arschat-M nutrient, Fe:Co:Ni metal ions (6 : 3 : 9 : 6 : 3). Methods used were identification and analysis of sea phytoplankton.  Determination of optimum growth condition, pure culture, and mass culture were using local raw materials-based engineered nutrients or MSSIP (M. Sjahrul-Syahruddin Kasim-Indah Raya-Paulina Taba). Determination of product density of sea phytoplankton biomass, analyses of carbohydrate content, and lipid biomass were done by using haemocytometer and microscope, Luff Schrol method, and soxhlet method (n-hexane as solvent), respectively. Morphology of phytoplankton was identified by using a digital camera microscope, SZ60/sZ60-61. Furthermore, to understand the effect of metal ions, Fe, Co, and Ni added into MSSIP nutrient, identification of nutrient before and after culturing process were done using XRF-Thermo-Fisher.  The results showed that Chlorella  vulgaris, Dunaliella salina, and Spirulina sp. were suitable as raw materials  to produce biofuel. Those three phytoplankton contained 0,3095 g/L, 0,3782 g/L, and 0,3325 g/L biomass, 32,49%w/w, 31,58%w/w, and 29,81%w/w carbohydrates; and  25,95%w/w, 26,82%w/w and 24,53%w/w lipid, respectively. Best optimum condition of culture were salinity of 30-35%, temperature of 20-30 °C, pH of 8-9, initial density of 2.5 x 104 cell/mL, light exposure of 40 watt, and continuously aerated with CO2. Based on our study, sea phytoplankton, Chlorella  vulgaris, Dunaliella salina, and Spirulina sp. have a high potency as source of bioethanol and biodiesel.Keywords: mass culture, superior nutrient MSSIP, sea phytoplankton biomass, Fe, Co, Ni metal ions

Determination of oxidative deterioration of milk powder and reconstitute milk by measurement of chemiluminescence

1982 ◽  
Vol 49 (4) ◽  
pp. 645-654 ◽  
Author(s):  
Ralph E. Timms ◽  
Peter Roupas ◽  
William P. Rogers
Keyword(s):  
Light Exposure ◽  
Scintillation Counter ◽  
Milk Powder ◽  
Background Level ◽  
Taste Panel ◽  
Oxidative Deterioration ◽  
Peroxide Values ◽  
Reconstituted Milk

SUMMARYA scintillation counter was used to measure chemiluminescence (CL) from milk powder and reconstituted milk. Only a small amount of CL, just above the background level, was observed from powders, but reconstituted milks emitted easily measurable CL. CL from milk was stimulated by exposure to light and found to decline gradually but non-exponentially after the exposure ceased. CL was at a maximum immediately after the milk was reconstituted from milk powder. Without light exposure, CL then declined gradually but non-exponentially over several hours to reach a constant value related to the level of oxidation of the powder. When determined under standard conditions 60 min after reconstitution, CL of milk reconstituted from stored milk powders correlated well with peroxide values and oxidized flavour as assessed by a taste panel.

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