scholarly journals Optimizing Delivery Characteristics of Curcumin as a Model Drug via Tailoring Mean Diameter Ranges of Cellulose Beads

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Lee Ken Voon ◽  
Suh Cem Pang ◽  
Suk Fun Chin
Keyword(s):  
Reaction Temperature ◽  
Surfactant Concentration ◽  
Regenerated Cellulose ◽  
Release Kinetic ◽  
Mean Diameter ◽  
The Mean ◽  
Model Drug ◽  
Fabrication Parameters ◽  
Cellulose Concentration

Spherical cellulose beads with tailored mean diameter between micrometer (20–80 μm) and nanometer (40–200 nm) ranges were fabricated from regenerated cellulose of paper wastes via water-in-oil (W/O) microemulsion and nanoprecipitation processes, respectively. The mean diameter ranges of cellulose beads were precisely controlled via modulating fabrication parameters such as stirring speed, surfactant concentration, cellulose concentration, and reaction temperature. By tailoring their mean diameter ranges and using curcumin as a model drug, cellulose beads with enhanced loading capacities and optimized release kinetic profiles of curcumin were fabricated.

scholarly journals Porous Cellulose Beads Fabricated from Regenerated Cellulose as Potential Drug Delivery Carriers

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Lee Ken Voon ◽  
Suh Cem Pang ◽  
Suk Fun Chin
Keyword(s):  
Drug Delivery ◽  
Release Kinetics ◽  
Morphological Characteristics ◽  
Cost Effective ◽  
Solution Concentration ◽  
Regenerated Cellulose ◽  
Release Kinetic ◽  
Loading Capacity ◽  
The Mean ◽  
Model Drug

Highly porous cellulose beads (CBs) of various mean sizes were successfully prepared from regenerated cellulose of paper wastes. The drug delivery characteristics of CBs with different mean sizes were investigated using curcumin as the model drug under controlled conditions. The loading capacity and efficiency of curcumin onto CBs were substantially influenced by factors such as their morphological characteristics, curcumin concentration, and duration of loading. The release kinetic profiles of curcumin from CBs of different mean sizes were investigated in media of pH values resembling digestive juices and intestinal fluids. Release kinetic models were used to simulate and elucidate release kinetics and mechanisms of curcumin from CBs under specific conditions. The loading capacity and efficiency of curcumin onto CBs could be enhanced via the optimization of curcumin solution concentration and the morphological characteristics of CBs, whereas the release kinetic profiles of curcumin from CBs could be modulated by varying the mean diameter of CBs. Optimized CBs derived from regenerated cellulose of paper wastes are potentially useful as cost-effective drug delivery carriers.

scholarly journals Morphological changes of ZnO nanostructures upon addition of Trisodium Citrate (Na3C6H5O7) at different reaction temperatures

2021 ◽  
Vol 5 (1) ◽  
pp. 18-22
Author(s):  
Aqilah Kamaruzaman ◽  
Nurul Akmal Che Lah
Keyword(s):  
Size Distribution ◽  
Reaction Temperature ◽  
Morphological Changes ◽  
Chemical Properties ◽  
Trisodium Citrate ◽  
Zno Nanostructure ◽  
Mean Diameter ◽  
Mean Size ◽  
The Mean ◽  
Physical And Chemical

Due to its interesting physical and chemical properties, zinc oxide (ZnO) is considered one of the front runners of numerous metal oxide semiconductors. In this paper, ZnO nanostructure are synthesised by hydrothermal method with trisodium citrate (TC) as the emulsfying agent. The mean diameetr of ZnO nanostructure are observed with increment of reaction temperature. The mean size results into no change to mean diameter upon increment of reaction temperature but the cumulative frequencies of size distribution showing ZnO nanostructure synthesised in higher temperature to have narrower size distribution. The addition of TC also results into much smaller ZnO nanostructure with mean diameter 8nm

scholarly journals Manganese Dioxide Nanowires of Tunable Dimensions Synthesized via a Facile Hydrothermal Route

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Ying Ying Kong ◽  
Suh Cem Pang ◽  
Suk Fun Chin
Keyword(s):  
Manganese Dioxide ◽  
Reaction Temperature ◽  
Homogeneous Solution ◽  
Hydrothermal Route ◽  
Initial Concentration ◽  
Aspect Ratios ◽  
Synthesis Parameters ◽  
Facile Hydrothermal Route ◽  
Mean Diameter ◽  
The Mean

Manganese dioxide (MnO2) nanowires of tunable dimensions were successfully synthesized via the facile water-bathing hydrothermal route. Homogeneous solution mixtures of KMnO4and MnSO4of varying compositions were being aged in a thermostated water bath under controlled conditions. The dimensional aspect ratios of MnO2nanowires formed were readily modulated by varying synthesis parameters such as the initial concentration of chemical precursors, reaction temperature, and aging duration. At fixed initial precursor concentrations, the mean diameter of MnO2nanowires decreased slightly from 57 nm to 53 nm with increased reaction temperature from 60°C to 90°C. The mean diameter of MnO2nanowires decreased linearly within the range of 104 nm and 35 nm as the initial concentration of both precursors was increased in turn within the range of 10 mmol and 40 mmol at fixed aging temperature and duration. Upon aging for 2 to 24 hours at 80°C, the mean diameter and length of MnO2nanowires were observed to vary within the range of 33–55 nm and 0.69–2.68 μm, respectively, which corresponded to the dimensional aspect ratio range of 21 to 49. Henceforth, MnO2nanowires of tunable dimensions could be synthesized through optimally controlled synthesis parameters.

Non-isothermal crystallization behavior of spinel crystals in FeO-SiO2-TiO2-V2O3-Cr2O3 slag

2018 ◽  
Vol 116 (1) ◽  
pp. 110
Author(s):  
Lixiong Shao ◽  
Jiang Diao ◽  
Wang Zhou ◽  
Tao Zhang ◽  
Bing Xie
Keyword(s):  
Cooling Rate ◽  
Crystallization Behavior ◽  
Crystal Size ◽  
Growth Mechanisms ◽  
Vanadium Slag ◽  
Growth Behaviour ◽  
Temperature Range ◽  
Chromium Spinel ◽  
Mean Diameter ◽  
The Mean

The growth behaviour of spinel crystals in vanadium slag with high Cr2O3 content was investigated and clarified by statistical analyses based on the Crystal Size Distribution (CSD) theory. The results indicate that low cooling rate and Cr2O3 content benefit the growth of spinel crystals. The chromium spinel crystals firstly precipitated and then acted as the heterogeneous nuclei of vanadium and titanium spinel crystals. The growth mechanisms of the spinel crystals at the cooling rate of 5 K/min consist two regimes: firstly, nucleation control in the temperature range of 1873 to 1773 K, in which the shapes of CSD curves are asymptotic; secondly, surface and supply control within the temperature range of 1773 to 1473 K, in which the shapes of CSD curves are lognormal. The mean diameter of spinel crystals increases from 3.97 to 52.21 µm with the decrease of temperature from 1873 to 1473 K.

scholarly journals Bark proportion of Scots pine industrial wood

2021 ◽  
Author(s):  
Ferréol Berendt ◽  
Erik Pegel ◽  
Lubomir Blasko ◽  
Tobias Cremer
Keyword(s):  
Supply Chain ◽  
Scots Pine ◽  
Bark Thickness ◽  
Wood Supply ◽  
Volume Proportion ◽  
Bark Damage ◽  
Mass Proportion ◽  
Mean Diameter ◽  
The Mean

AbstractBark characteristics are not only used in the forest-wood supply chain, for example to calculate standing volumes, but also to transform wood volumes and masses. In this study, bark thickness, bark volume and bark mass were analyzed on the basis of 150 Scots pine discs, with a mean diameter of 13 cm. The mean double bark thickness was 3.02 mm, the mean bark volume proportion was 5.6% and mean bark mass proportion was 3.3%. Bark proportions were significantly affected by the log-specific variables ‘diameter over bark’, ‘proportion of bark damage’ and ‘double bark thickness’.

CONTROLLABLE CHEMICAL VAPOR DEPOSITION SYNTHESIS OF SINGLE-WALL CARBON NANOTUBES USING MIST FLOW METHOD

NANO ◽  
2012 ◽  
Vol 07 (06) ◽  
pp. 1250045 ◽  
Author(s):  
YUN SUN ◽  
RYO KITAURA ◽  
TAKUYA NAKAYAMA ◽  
YASUMITSU MIYATA ◽  
HISANORI SHINOHARA
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Single Wall Carbon Nanotubes ◽  
Flow Method ◽  
Mist Flow ◽  
Mean Diameter ◽  
The Mean

The influences of synthesis parameters on the mean diameter and diameter distribution of as-grown single-wall carbon nanotubes (SWCNTs) with chemical vapor deposition (CVD) using the mist flow method have been investigated in detail with Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We found that CVD reaction temperature and flow rate play an essential role in controlling the mean diameter and the quality of as-grown SWCNTs. Furthermore, we found that the carbon supply kinetics can be a dominant factor to determine the diameter of as-grown SWCNTs in the present mist flow method. Under a different combination of various parameters, the mean diameter of SWCNTs can be varied from 0.9 nm to 1.5 nm controllably.

Initial Clinical Experience with Percutaneous Atherectomy in the Infragenicular Arteries

2003 ◽  
Vol 10 (5) ◽  
pp. 987-993 ◽  
Author(s):  
Thomas Zeller ◽  
Ulrich Frank ◽  
Karlheinz Bürgelin ◽  
Uwe Schwarzwälder ◽  
Peter-Christian Flügel ◽  
...  
Keyword(s):  
Balloon Angioplasty ◽  
Ankle Brachial Index ◽  
Peroneal Artery ◽  
Lesion Length ◽  
Anterior Tibial Artery ◽  
Tibial Artery ◽  
Below The Knee ◽  
Directional Atherectomy ◽  
Mean Diameter ◽  
The Mean

Purpose: To evaluate the efficacy and safety of a new atherectomy device for the treatment of infragenicular lesions in arteries with a reference diameter of at least 2.5 mm. Methods: Twenty-seven below-the-knee lesions in 17 patients (12 men; mean age 69±12 years) with chronic peripheral arterial occlusive disease were treated with directional atherectomy. The target lesion was in the popliteal artery (segment 3) in 2 (7%) cases, the tibioperoneal trunk in 12 (44%), the peroneal artery in 8 (30%), the anterior tibial artery in 2 (7%), and the posterior tibial artery in 3 (11%). Six (22%) of the lesions were in-stent stenoses. The mean diameter stenosis was 87%±9%, and the mean lesion length was 34±24 mm. Results: All but 2 (7%) of the lesions could be treated successfully (residual stenosis <30%) with the atherectomy catheter (93% technical success) using an average of 5±2 (range 1–10) passes of the device. Six lesions (22%) were treated after predilation and 21 (78%) with primary atherectomy. In 8 (30%) lesions, additional balloon angioplasty was performed. The 2 failures were in heavily calcified lesions through which the device could not pass despite predilation. The mean diameter stenosis after atherectomy was 14%±22% (range 0%–90%); after additional balloon angioplasty, the mean residual stenoses reduced to 12%±21% (range 0%–100%). One (6%) of the 2 patients who failed atherectomy sustained a thrombotic occlusion of the target vessel. This complication was treated successfully with local lysis, but the vessel reoccluded 3 days later; a stent was implanted. The mean ankle-brachial index increased from 0.50±0.27 to 0.86±0.40 before discharge. Conclusions: Below-the-knee native vessel lesions and in-stent restenoses with a diameter of at least 2.5 mm can be treated successfully and safely with this new atherectomy catheter. Additional balloon angioplasty was necessary in only a few cases.

Mean Diameters in Parallel-Flow and Counter-Flow Aerosol Systems

1976 ◽  
Vol 98 (2) ◽  
pp. 297-302 ◽  
Author(s):  
K. G. T. Hollands ◽  
K. C. Goel
Keyword(s):  
Mass Transfer ◽  
Continuous Phase ◽  
General Concept ◽  
Parallel Flow ◽  
General Definition ◽  
Single Pair ◽  
Counter Flow ◽  
Mean Diameter ◽  
The Mean ◽  
Definition Of

The general concept of the mean diameter of the disperse phase of an aerosol system, first introduced by Mugele and Evans in 1951, has proven to be a very useful one. In this concept, the proper mean diameter, xp,q, is characterized by a single pair of indices, p and q, which are dependent on the actual type of aerosol system under consideration. This paper re-examines the validity of this concept of mean diameter in heat and mass transfer aerosol systems. The concept is found to be applicable only under a very narrow range of conditions. Attention is then given to a more general definition of a mean diameter, applicable to aerosol heat or mass exchangers. Analyses of these devices shows that the more general mean diameter is a function of the capacity rate ratio, R, and effectiveness of the heat exchanger, ε. Solutions to the governing equations have permitted the mean diameter to be presented graphically as a function of these variables. These solutions are given for two types of particle size distributions, the Rosin-Rammler and the log-probability, and for both parallel-flow and counter-flow heat exchangers. The solutions are, however, restricted to cases where the resistance to heat or mass transfer lies exclusively in the continuous phase.

scholarly journals Nanometer Scale Tomographic Investigation of Fine Scale Precipitates in a CuFeNi Granular System by Three-Dimensional Field Ion Microscopy

2012 ◽  
Vol 18 (5) ◽  
pp. 1129-1134 ◽  
Author(s):  
Sophie Cazottes ◽  
François Vurpillot ◽  
Abdeslem Fnidiki ◽  
Dany Lemarchand ◽  
Marcello Baricco ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Precise Determination ◽  
Atomic Scale ◽  
Granular System ◽  
Field Ion Microscopy ◽  
Mean Diameter ◽  
The Matrix ◽  
The Mean ◽  
Ion Microscopy

AbstractThe microstructure of Cu80Fe10Ni10 (at. %) granular ribbons was investigated by means of three-dimensional field ion microscopy (3D FIM). This ribbon is composed of magnetic precipitates embedded in a nonmagnetic matrix. The magnetic precipitates have a diameter smaller than 5 nm in the as-spun state and are coherent with the matrix. No accurate characterization of such a microstructure has been performed so far. A tomographic characterization of the microstructure of melt spun and annealed Cu80Fe10Ni10 ribbon was achieved with 3D FIM at the atomic scale. A precise determination of the size distribution, number density, and distance between the precipitates was carried out. The mean diameter for the precipitates is 4 nm in the as-spun state. After 2 h at 350°C, there is an increase of the size of the precipitates, while after 2 h at 400°C the mean diameter of the precipitates decreases. Those data were used as inputs in models that describe the magnetic and magnetoresistive properties of this alloy.

Inoptimality losses in forest management decisions caused by errors in an inventory based on airborne laser scanning and aerial photographs

2010 ◽  
Vol 40 (12) ◽  
pp. 2427-2438 ◽  
Author(s):  
Md. Nurul Islam ◽  
Mikko Kurttila ◽  
Lauri Mehtätalo ◽  
Timo Pukkala
Keyword(s):  
Input Data ◽  
Laser Scanning ◽  
Basal Area ◽  
Airborne Laser Scanning ◽  
Aerial Photographs ◽  
Stand Age ◽  
Inventory Data ◽  
Airborne Laser ◽  
Mean Diameter ◽  
The Mean

Errors in inventory data may lead to inoptimal decisions that ultimately result in financial losses for forest owners. We estimated the expected monetary losses resulting from data errors that are similar to errors in laser-based forest inventory. The mean loss was estimated for 67 stands by simulating 100 realizations of inventory data for each stand with errors that mimic those in airborne laser scanning (ALS) based inventory. These realizations were used as input data in stand management optimization, which maximized the present value of all future net incomes (NPV). The inoptimality loss was calculated as the difference between the NPV of the optimal solution and the true NPV of the solution obtained with erroneous input data. The results showed that the mean loss exceeded €300·ha–1 (US$425·ha–1) in 84% of the stands. On average, the losses increased with decreasing stand age and mean diameter. Furthermore, increasing errors in the basal area weighted mean diameter and basal area of spruce were found to significantly increase the loss. It has been discussed that improvements in the accuracy of ALS-based inventory could be financially justified.

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