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1
Sahu, Nisha, Sukrita Shriwas, Yeendeswari Gendre, Aakanksha Sinha, and S. J. Daharwal. "A Review on Various Analytical Methodologies of Naproxen." Journal of Ravishankar University (PART-B) 36, no. 1 (July 13, 2023): 94–103. http://dx.doi.org/10.52228/jrub.2023-36-1-9.
Анотація:
Naproxen is a Nonsteroidal Anti-Inflammatory Drug (NSAID). It is mostly used to treat pain or inflammation caused by conditions such as arthritis, gout, tendinitis or menstrual cramps. Naproxen is available in isolated dose with various similar anti-inflammatory drugs, i.e.; esomeprazole, pantoprazole, paracetamol, ranitidine, sumatriptan and ibuprofen. This survey evaluates various methods for the analysis of Naproxen in bulk drugs and formulated products. Analytical procedures are critical for determining compositions, they allow as to obtain both qualitative and quantitative results utilizing by the advanced analytical tools. This include HPLC, HPTLC, UV- spectrophotometry, capillary electrophoresis, and electrochemical meth-ods. The UV-spectrophotometry method is applied for the investigation of Naproxen in biologi-cal media, bulk samples and in various dosage formulations. The HPLC technique of Naproxen alone and the combination, including parameters such as matrix, stationary phase, mobile phase, wavelength detection, etc. HPTLC method parameters such as stationary phase, mobile combi-nation phase, RF value, etc. To maintain high commercial product quality standards and to ad-here to regulatory requirements, analytical technique development is necessary. Drug concen-trations are measured using bioanalytical techniques. Development and validation of bioanalyt-ical method is important to understand the pharmacokinetics of any drug and/or its metabolites.
2
Mahuzie, Pierre-Etienne, Brian J. Clark, Andy J. Crumpton, and Kevin D. Altria. "Quantitative microemulsion electrokinetic capillary chromatography analysis of formulated drug products." Journal of Separation Science 24, no. 9 (September 1, 2001): 784–88. http://dx.doi.org/10.1002/1615-9314(20010901)24:9<784::aid-jssc784>3.0.co;2-2.
3
Kahn, Bobbi B., and David F. Tomkins. "Determination of Acetochlor in Technical and Formulated Products by Capillary Gas Chromatography." Journal of AOAC INTERNATIONAL 84, no. 2 (March 1, 2001): 317–22. http://dx.doi.org/10.1093/jaoac/84.2.317.
Анотація:
Abstract A peer-verified gas chromatographic (GC) method is presented for the weight percent (wt %) determination of acetochlor herbicide in technical and formulated products. During method development, the method was found to be rugged by the Youden Ruggedness Test. Two laboratories with experience in the wt % determination of acetochlor in various matrixes participated in this study. Each laboratory received 10 blind duplicate test samples of the following 5 matrixes: one acetochlor technical and 4, different, emulsifiable concentrate (EC) formulations—Harness® EC (MON 5841), Harness ® Export/Fist (MON 8435), Surpass® EC (HF), and Surpass ® EC (LF). Each participant was asked to make duplicate weighings of each of the test samples and to inject each test sample solution twice. All test samples were analyzed on the same day, and 8 data points (replicates) per matrix were obtained. The test samples were dissolved in acetone that contained dipentyl phthalate as an internal standard. They were analyzed by GC on a 15 m capillary column by using split injection and a flame ionization detector. Acetochlor (wt %) was determined by comparing the ratios of peak area of acetochlor/peak area of dipentyl phthalate internal standard obtained for the test sample and calibration solutions. Repeatability of the method, expressed as the within-laboratory (between replicates) relative standard deviation (RSDr), was found to be 0.09–0.77% for the 5 matrixes. Reproducibility of the method, expressed as the within-test sample relative standard deviation (RSDR), was found to be 0.18–0.78% for the 5 matrixes.
4
Lo, Chi-Chu, Yuh-Jyuan Lee, and Chai-Ju Chang. "High-Performance Capillary Electrophoretic Method for the Determination of Blasticidin S in Formulated Products." Journal of Agricultural and Food Chemistry 43, no. 11 (November 1995): 2892–95. http://dx.doi.org/10.1021/jf00059a023.
5
Masukawa, Yoshinori. "Separation and determination of basic dyes formulated in hair care products by capillary electrophoresis." Journal of Chromatography A 1108, no. 1 (March 2006): 140–44. http://dx.doi.org/10.1016/j.chroma.2006.01.007.
6
Kikta, Edward J., O. O. Bennett, L. Bradbury, P. Coco, K. Henley, A. Hernandez, R. Larson, et al. "Gas Chromatographic Determination of Bifenthrin in Technical and Selected Formulated Products: Collaborative Study." Journal of AOAC INTERNATIONAL 94, no. 2 (March 1, 2011): 453–58. http://dx.doi.org/10.1093/jaoac/94.2.453.
Анотація:
Abstract A GC method for the analysis of technical and formulated bifenthrin samples was evaluated in a collaborative study. Bifenthrin is determined by using a 50 (trifluoropropyl)-methylpolysiloxane wide-bore capillary column and flame ionization detector. Ten samples, consisting of four formulations and a technical material were analyzed by 12 collaborators using Youden pairs. The four formulation types included in this study were microemulsion (ME), wettable powder (WP), suspension concentrate (SC), and emulsifiable concentrate (EC). Variability in the analysis of two of the formulation types, SC and EC, was later found to be due to the noncommercial containers used to hold the test samples. Because of this, valid data could not be obtained for the EC and SC. For the two formulations for which valid data could be obtained, ME and WP, and the technical chemical, accuracy and variability results are typical of large data sets. For the technical chemical and the two formulations for which valid data were obtained, Official First Action is recommended.
7
Lo, Chi-Chu, and Yi-Min Hsiao. "High-Performance Capillary Electrophoretic Method for the Determination of Antibiotic Fungicide Kasugamycin in Formulated Products." Journal of Agricultural and Food Chemistry 44, no. 8 (January 1996): 2231–34. http://dx.doi.org/10.1021/jf9601675.
8
Vargyas, Linda D., Gregory E. Walls, Richard L. Cryberg, William R. Bramstedt, Frank J. Wang, Hugh L. Mayo, and Gary L. Eilrich. "Simultaneous Determination of Chlorothalonil and Hexachlorobenzene in Technical and Formulated Materials by Capillary Gas Chromatography." Journal of AOAC INTERNATIONAL 78, no. 3 (May 1, 1995): 604–9. http://dx.doi.org/10.1093/jaoac/78.3.604.
Анотація:
Abstract A capillary gas chromatographic method using flame ionization detection was developed for simultaneous assay of chlorothalonil and hexachlorobenzene in technical material and formulated products. Method precision is excellent, and the method allows simultaneous determination of one chemical impurity. The method uses an internal normalization reagent (n-butyl phthalate). Modification and extension of the method to formulated products, including wettable powders, water-based flowables, and dispersible (or dry flowable) granular formulations, are discussed. Preliminary statistical analysis of intra- and interlaboratory comparisons was performed to evaluate method ruggedness. Average relative standard deviations for technical materials were 0.34 and 0.17% from 2 laboratories. Additional method validation studies were conducted to examine the influence of pH, solvent systems, gas chromatographic systems, and temperature conditions on different formulations.
9
Di Rosa, Claudia, Elisa De Arcangelis, Virginia Vitelli, Salvatore Crucillà, Martina Angelicola, Maria Carmela Trivisonno, Francesco Sestili, et al. "Effect of Three Bakery Products Formulated with High-Amylose Wheat Flour on Post-Prandial Glycaemia in Healthy Volunteers." Foods 12, no. 2 (January 9, 2023): 319. http://dx.doi.org/10.3390/foods12020319.
Анотація:
Both Glycaemic index (GI) and Glycaemic Load (GL) were introduced to measure the impact of a carbohydrate-containing food on blood glucose. From this perspective, high-amylose (HA) flours, with a higher percentage of resistant starch (RS), may represent a suitable raw material to improve the glycaemic response. The present work aims to investigate the GI of HA bakery products (biscuits, taralli and bread) compared to products obtained from conventional flour. Ten healthy volunteers were enrolled and their capillary blood glucose was measured every 15 min for 2 h after the consumption of HA and control products containing 50 g of available carbohydrates. On average, in the three bakery products, the amount of total starch replaced by RS was equal to 12%. HA biscuits and HA bread showed significantly lower GI than their control counterparts (p = 0.0116 and p = 0.011, respectively) and better glycaemic control. From the survey to assess liking and willingness to pay on HA snacks, HA packages received an average premium of €0.66 compared to control products. Although HA flour results in lower GI in both biscuits and bread, further studies are needed to evaluate the correct composition of HA products to have beneficial effects on post-prandial glycaemia.
10
Vladimirova, Daria, Vladimir Pervadchuk, and Yuri Konstantinov. "Manufacture of Microstructured Optical Fibers: Problem of Optimal Control of Silica Capillary Drawing Process." Computation 12, no. 5 (April 23, 2024): 86. http://dx.doi.org/10.3390/computation12050086.
Анотація:
The effective control of any technological process is essential in ensuring high-quality finished products. This is particularly true in manufacturing knowledge-intensive and high-tech products, including microstructured photonic crystal fibers (PCF). This paper addresses the issues of stabilizing the optimal control of the silica capillary drawing process. The silica capillaries are the main components of PCF. A modified mathematical model proposed by the authors is used as the basic model of capillary drawing. The uniqueness of this model is that it takes into account the main forces acting during drawing (gravity, inertia, viscosity, surface tension, pressure inside the drawn capillary), as well as all types of heat transfer (heat conduction, convection, radiation). In the first stage, the system of partial differential equations describing heat and mass transfer was linearized. Then, the problem of the optimal control of the drawing process was formulated, and optimization systems for the isothermal and non-isothermal cases were obtained. In the isothermal case, optimal adjustments of the drawing speed were obtained for different objective functionals. Thus, the proposed approach allows for the constant monitoring and adjustment of the observed state parameters (for example, the outer radius of the capillary). This is possible due to the optimal control of the drawing speed to obtain high-quality preforms. The ability to control and promptly eliminate geometric defects in the capillary was confirmed by the analysis of the numerical calculations, according to which even 15% deviations in the outer radius of the capillary during the drawing process can be reduced to 4–5% by controlling only the capillary drawing speed.
11
Lo, Chi-Chu, and Yi-Ming Hsiao. "Comparison of Micellar Electrokinetic Capillary Chromatographic Method with High-Performance Liquid Chromatographic Method for the Determination of Imidazolidine-2-thione (Ethylenethiourea) in Formulated Products." Journal of Agricultural and Food Chemistry 45, no. 8 (August 1997): 3118–22. http://dx.doi.org/10.1021/jf960655c.
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HENNING, PATRICK, MARIO OHLBERGER, and BEN SCHWEIZER. "HOMOGENIZATION OF THE DEGENERATE TWO-PHASE FLOW EQUATIONS." Mathematical Models and Methods in Applied Sciences 23, no. 12 (August 18, 2013): 2323–52. http://dx.doi.org/10.1142/s0218202513500334.
Анотація:
We analyze two-phase flow in highly heterogeneous media. Problems related to the degeneracy of the permeability coefficient functions are treated with a new concept of weighted solutions. Instead of the pressure variables we formulate the problem with the weighted pressure function ψ, which is obtained as the product of permeability and pressure. We perform the homogenization limit and obtain effective equations in the form of a two-scale limit system. The nonlinear effective system is of the classical form in the non-degenerate case. In the degenerate case, the two-scale system uses again a weighted pressure variable. Our approach allows to work without the global pressure function. Even though internal interfaces are included, our approach provides the homogenization limit without any smallness assumptions on permeabilities or capillary pressures.
13
Mascorro, Joe A., and Gerald S. Kirby. "Novel epoxy/anhydride alternatives for biological electron microscopy: Physical and performance characteristis of embed 812 and LX 112 in combination with NSA/NMA/DMAE." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 1000–1001. http://dx.doi.org/10.1017/s0424820100156985.
Анотація:
Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.
14
Rodrigues, Barbara, Jhones Sarturi, Leandro Samia, Ramon C. Alvarenga, Alexandre Berndt, Fernando Souza, Beatriz Q. Reis, and Kaliu G. Silva. "135 Growth Performance, Carcass Characteristics, and Methane Emissions of Feedlot Young Bulls." Journal of Animal Science 101, Supplement_1 (May 1, 2023): 80–81. http://dx.doi.org/10.1093/jas/skad068.095.
Анотація:
Abstract The growth performance, carcass characteristics, and methane emissions from feedlot beef cattle fed a high-lipid finishing diet (7.3% of ether extract) were evaluated. Fifty long-yearling young bulls were divided into two groups following their breed composition: Nellore (n = 25) and Angus × Nellore crossbred (n = 25), and randomly assigned into 4 pens (12 or 13 animals/pen) following a completely randomized design. Animals were sourced from the same breeding season and endured a grazing growing phase in Megathyrsus maximus cv. Mombaça pasture, with protein and energy supplement offered at 0.2% of body weight (BW). The feedlot phase comprehended 105 days of feed, and the diet (80% concentrate) was formulated to meet or safely exceed the beef cattle requirements to target an average daily gain (ADG) of 1.6 kg/day, in which major ingredients were represented by (% DM basis): sorghum silage (20%), ground corn (57.6%), ground soybean seed as the lipid source (20.4%), and a mineral/vitamin premix (2%). Titanium dioxide (TiO2) was used as an external marker to estimate dry matter intake (DMI), while 10 g was administered to 12 animals of each group, once daily, for 10 d. Animals were weighed every 30 d after a 16-h fasting period, and the day before slaughter to obtain the final body weight (FBW). Enteric methane emissions were measured using the sulfur hexafluoride (SF6) tracer gas technique in the same animals used for intake measurements. The animals were equipped with gas collection halters attached to pre-evacuated polyvinyl chloride (PVC) sampling canisters with a capillary tube (0.127 mm diameter), made to permit 50% filling in 24 h, for five consecutive days. Data were analyzed using the statistical analysis software R (R CORE TEAM, 2021), and the effect of breed on carcass traits and methane emissions was evaluated using the completely randomized design one-way, in which treatment means were compared by the F test (P < 0.05). The crossbred animals had a greater DMI (12.6 vs.0.6 kg/d), gain efficiency (0.16 vs. 0.14), initial BW upon feedlot phase (509.8 vs. 444.7 kg), FBW (720.8 vs. 595.6, kg), ADG (2.01 vs..44 kg), and hot carcass weight (404.7 vs. 345.0 kg; P < 0.01) compared with Nellore cattle. No difference was observed in dressing percentage between genetic groups (P = 0.28). Nellore animals produced more methane expressed as CH4 g/kg ADG (266.0 vs.73.4; P < 0.01), and tended to produce more methane expressed as CH4 kg/DMI (35.4 vs. 27.7; P = 0.08), and CH4 g/kg CW (1.09 vs. 0.87; P = 0.11). Crossbred F1 Nellore/Angus young bulls showed improved feedlot performance and carcass weight, while not negatively affecting total CH4 production, but rather lessening CH4 emissions per unit of beef produced.
15
Hladyshev, V. V., S. І. Sоkolovskyi, I. V. Sobko, Ugіs Kletnieks, and Audrius Butkevichius. "The justification of the optimal composition and research of a local hemostatic agent based on naturally occurring polysaccharides." Current issues in pharmacy and medicine: science and practice 16, no. 2 (July 3, 2023): 141–46. http://dx.doi.org/10.14739/2409-2932.2023.2.281238.
Анотація:
The analysis of existing methods and products for controlling bleeding reveals that medical means exhibit significantly higher efficacy compared to mechanical methods of achieving hemostasis. However, it is important to note that medical means cannot entirely replace surgical hemostasis in cases of severe bleeding from large veins and arteries. In emergency situations, such as during military conflicts or workplace injuries, the use of local contact hemostatic agents is preferred. These agents do not require specialized skills for application, making them accessible to individuals in need of immediate assistance. If included in a first-aid kit, these agents enable victims to address minor injuries promptly and control bleeding. In critical bleeding situations, any nearby individual can use the tool to provide aid. Given the ongoing military activities within our country’s territory, the development of effective domestic hemostatic agents has become an urgent priority. This initiative aims to ensure the availability of such products to our military personnel. Aim. The aim of this work is to justify the optimal composition of a local hemostatic agent based on readily available raw materials and feasible technologies. Materials and methods. After conducting an extensive review of domestic and foreign literature, the basis for the development of the future contact hemostatic agent was chosen to be adsorbing materials derived from biologically active components of mineral, synthetic, phyto-, and organic origins. The focus of this study is on natural polysaccharides with potential hemostatic activity, specifically alginate, kappa carrageenan, guar gum, and xanthan gum. One key property of polysaccharides is their ability to swell, which positively influences hemostasis. The hemostatic effect of model hemostatic compositions was evaluated using a femoral artery bleeding model induced by mechanical damage. Additionally, a model involving capillary-parenchymal bleeding from a laceration wound on the liver in adult rats was employed for further investigation. Results. Experimental studies have provided evidence of the hemostatic effect of natural polysaccharides due to their water absorption and swelling properties. In comparison with well-known medical products Celox and Revul®, substances with hemostatic activity, including alginate, kappa carrageenan GU 805, and the comparative drug Celox, have demonstrated significant reductions in bleeding time. Specifically, alginate, kappa carrageenan GU 805, and Celox have shown reductions of 38 %, 53 %, and 57 % respectively, compared to the positive control (PC) group. To enhance the hemostatic activity, a combination of the leading compounds with the addition of 7 % calcium gluconate was developed. The inclusion of calcium gluconate in the combination is associated with the involvement of calcium ions in all stages of blood coagulation, thereby increasing the overall hemostatic effect of the combination. Based on the obtained results, it can be concluded that substances with hemostatic activity, such as alginate, kappa carrageenan GU 805 in combination with calcium gluconate, miramistin, and a mixture of phytocomponents, as well as the comparative drugs Celox and Revul®, reliably reduce bleeding time by 46 %, 47 %, 37 %, and 36 %, respectively, in comparison to the PC group. Conclusions. The optimal composition of a contact hemostatic agent, formulated as a multicomponent powder known as Plantor, has been developed. This composition is based on natural saccharides and incorporates a complex of antiseptic and wound-healing substances derived from natural and synthetic sources. The formulation of Plantor demonstrates optimal consistency, biopharmaceutical properties, and pharmacotechnological characteristics. The addition of 7 % calcium gluconate to the composition was found to effectively enhance the level of hemostatic activity. This enhancement is attributed to the involvement of calcium ions in all stages of blood coagulation. Experimental studies conducted using a hemostatic model have confirmed that the proposed composition of the pharmacotherapeutic agent significantly reduces bleeding time by 47 % and accelerates the overall process of hemostasis. The observed efficacy of the Plantor formulation surpasses that of reference local hemostatic agents, indicating its superior effectiveness in promoting hemostasis.
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Ypma, J. G. J. "Analytical and Numerical Modeling of Immiscible Gravity-Stable Gas Injection Into Stratified Reservoirs." Society of Petroleum Engineers Journal 25, no. 04 (August 1, 1985): 554–64. http://dx.doi.org/10.2118/12158-pa.
Анотація:
Abstract A two-dimensional (2D) analytical model is presented for gas/oil gravity drainage in a homogeneous, dipping reservoir. The sensitivity of gas/oil gravity drainage to key variables such as injection rate, oil relative permeability, and permeability anisotropy can be determined quickly with this model. Example calculations show that miscible-like recovery efficiencies are possible with immiscible gas injection into high-permeability dipping reservoirs with light oil. A procedure based on the analytical model has been developed to simulate immiscible gas injection into highly stratified reservoirs accurately. This simulation procedure allows a great deal of geological detail to be incorporated into reservoir models, because it permits relatively coarse grids. Application of the simulation procedure to a reservoir containing many discontinuous shales reveals that the presence of shales may favorably affect the recovery efficiency of an immiscible gas-injection process. Introduction Gas injection increasingly is being applied as a secondary or tertiary recovery process. High-permeability, light-oil reservoirs with a reasonable reservoir dip are particularly suitable candidates for gas injection. In these reservoirs, a gravity-stable injection scheme is often possible, leading to high sweep efficiencies. If the injection process is carried out at sufficiently high pressure, process is carried out at sufficiently high pressure, favorable phase behavior between reservoir fluid and injection gas can contribute significantly to the recovery of oil. Miscibility, however, is by no means always necessary to obtain high displacement efficiencies. Even in the case of an entirely immiscible displacement, a high displacement efficiency is possible if gravity drainage is the dominant production mechanism. Laboratory experiments have shown that, the residual oil saturation after gas invasion, is virtually zero in highly permeable sandstone cores containing connate water. The ultimate recovery of an immiscible process is then close to 100%. Whether oil saturations process is then close to 100%. Whether oil saturations in the gas-invaded zone will approach the residual value within the lifetime of a particular reservoir depends on the rate of gravity drainage for this reservoir. This problem, which is the main subject of this paper, has been studied by both analytical means and numerical simulation. In the following, first a 2D analytical model is introduced for gas/oil gravity drainage in a homogeneous, dipping reservoir. The model combines aspects from both one-dimensional (1D) vertical Buckley-Leverett drainage theory and Dietz' segregated flow theory for dipping reservoirs. Assumptions underlying the model have been verified by 2D cross-sectional simulations. Second, a procedure based on the analytical gravity-drainage procedure based on the analytical gravity-drainage model has been developed to simulate immiscible secondary gas injection into a highly stratified reservoir accurately. This is illustrated with an example of gas injection into a reservoir containing discontinuous shale layers. Analytical Model for Gravity Drainage Description of the Model. In this section, an approximate analytical model is formulated for immiscible, gravity-stable gas/oil displacement in a homogeneous, dipping layer. Fig. 1 shows a schematic cross section of the draining reservoir with some relevant flow characteristics. In this model, oil is assumed to be produced from downdip wells near the oil/water contact at a rate that ensures a gravity-stable displacement, while gas is injected in updip wells near the crest to fill the voidage. This causes the gas/oil contact (GOC) to move downward gradually. Behind the GOC some oil will be left, the amount of which depends on the oil relative permeability and on the tilt and rate of descent of the GOC. The gas-invaded region will continue to produce oil by after-drainage; this oil will collect at the bottom of the reservoir in a thin oil layer, which flows to the producers with the along-dip component of gravity as driving force. To make the essentially 2D model amenable to analytical calculation, the following assumptions are introduced.The model has infinite gas mobility.The model has negligible gas/oil capillary pressure. pressure.The GOC moves at a constant velocity, v GOC, x, and at a constant tilt angle, given by Dietz' theory for gravity-stable segregated flow in dipping reservoirs (evaluated for infinite gas mobility) as.............(1)with u max, x being the maximum along-dip gravity drainage ratei.e., in the direction of bulk fluid flow. This rate is defined as..............(2) SPEJ p. 554
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Liang, Emily C., Erik L. Kimble, Aya Albittar, Jennifer J. Huang, Andrew J. Portuguese, Aiko Torkelson, Delaney Kirchmeier, et al. "Phase I/II Study to Evaluate the Safety, Feasibility, and Efficacy of FP-1201 (Intravenous Interferon-Beta-1a) to Prevent Toxicities after CD19-Directed CAR T-Cell Therapy: Trial in Progress." Blood 142, Supplement 1 (November 28, 2023): 4860. http://dx.doi.org/10.1182/blood-2023-173152.
Анотація:
BACKGROUND CD19 chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of patients with relapsed/refractory B-cell malignancies. Yet it remains limited by potentially life-threatening toxicities such as CRS and ICANS. The risk of CRS and ICANS restricts the use of CD19 CAR T-cell therapy to large academic centers and leads to high healthcare resource utilization. Current toxicity prevention strategies have shown limited efficacy to date (prophylactic steroids with axi-cel: CRS, 80%; ICANS, 60%; Oluwole, BJH, 2021; early intervention with brexu-cel: CRS, 89%; ICANS, 60%; Shah, The Lancet, 2021). Our group has shown that endothelial activation and dysfunction are associated with the development of CRS and ICANS, suggesting a key role of increased vascular permeability and blood-brain barrier damage in their pathogenesis (Hay, Blood, 2017). Type-I interferons (IFN-alpha and beta) are major regulators of CD73 expression by endothelial cells, an enzyme critical to the maintenance of endothelial integrity. CD73 breaks down extracellular pro-inflammatory ATP into anti-inflammatory adenosine. In addition, extracellular ATP has been shown to be a major and early driver of systemic inflammation upstream from IL-6 production (Cauwels, Cell Death Dis, 2014), which is associated with severe CRS and ICANS. Preclinical models have demonstrated that IFN-beta-1a treatment is associated with reduced capillary and blood-brain barrier permeability via upregulation of CD73 expression (Floris, J Neuroimmunol, 2002; Kraus., Ann Neurol, 2004; Niemela, Eur J Immunol, 2008). In humans, two recombinant IFN-beta-1a therapies are FDA-approved for the treatment of multiple sclerosis. IFN-beta-1a given intravenously (IV) maximizes the drug's bioavailability and its protective effects on the endothelium. In a study of patients with ARDS, IV IFN-beta-1a (FP-1201 and FP-1201-lyo) was safe and induced CD73 expression (Bellingan, Lancet Respir Med 2014). Given the known effects of IFN-beta-1a on preserving endothelial function and blood-brain barrier integrity, we hypothesize that IV IFN-beta-1a (FP-1201) may prevent CRS and ICANS following CD19 CAR T-cell therapy ( Figure 1A). Since higher rates of severe CRS and ICANS have been reported after axi-cel and brexu-cel, which contain CD28-costimulatory domains, we will restrict the inclusion criteria to patients treated with these products to analyze a population with a higher unmet need and a more homogeneous risk of CRS/ICANS. STUDY DESIGN AND METHODS Objectives and endpoints: Primary objective: To evaluate the safety and feasibility of FP-1201 in patients undergoing treatment with axi-cel or brexu-cel with two co-primary endpoints: i) to estimate the incidence of dose-limiting toxicity rates within the first 14 days following the last administration of FP-1201; ii) to study the type, frequency, and severity of adverse events according to the NCI CTCAE v5.0 from the first administration of FP-1201 and until day +28 after CAR T-cell infusion Secondary objectives: i) To decrease the incidence and severity of ICANS; ii) to decrease the incidence and severity of CRS; iii) to decrease corticosteroid usage; iv) to evaluate the effect of FP-1201 on anti-tumor efficacy Exploratory objectives: To characterize the in vivo effects of FP-1201 on endothelial function, the systemic cytokine milieu, and CAR T-cell function Key inclusion criteria: Adults ≥18 years of age with Karnofsky performance status ≥60% and B-cell non-Hodgkin lymphoma eligible for treatment with axi-cel or brexu-cel Key exclusion criteria: Known hypersensitivity to IFN-beta or major organ dysfunction FP-1201 administration: The FDA-approved IFN-beta-1a Rebif® will be formulated for IV administration (FP-1201). Participants will receive FP-1201 at one of four dose levels detailed in Figure 1B. Statistical design and sample size: We will use a Bayesian Optimal Interval Design to guide the FP-1201 dose escalation. We will plan to treat up to 24 participants. SUMMARY This is a phase I/II study of IV IFN-beta-1a in preventing CRS and ICANS following axi-cel and brexu-cel. The aim is to demonstrate safety and efficacy and to investigate the biologic mechanisms of IFN-beta-1a in preventing endothelial dysfunction.Additional preclinical and preliminary clinical data will be presented at the meeting. This study is registered on clinicaltrials.gov as NCT05936229.
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Kantzas, Apostolos, Minghua Ding, and Jong Lee. "Residual Gas Saturation Revisited." SPE Reservoir Evaluation & Engineering 4, no. 06 (December 1, 2001): 467–76. http://dx.doi.org/10.2118/75116-pa.
Анотація:
Summary The determination of residual gas saturation in gas reservoirs from long spontaneous and forced-imbibition tests is addressed in this paper. It is customarily assumed that when a gas reservoir is overlaying an aquifer, water will imbibe into the gas-saturated zone with the onset of gas production. The process of gas displacement by water will lead to forced imbibition in areas of high drawdown and spontaneous imbibition in areas of low drawdown. It is further assumed that in the bulk of the reservoir, spontaneous imbibition will prevail and the reservoir will be water-wet. A final assumption is that the gas behaves as an incompressible fluid. All these assumptions are challenged in this paper. A series of experiments is presented in which it is demonstrated that the residual gas saturation obtained by a short imbibition test is not necessarily the correct residual gas saturation. Imbibition tests by different methods yield very different results, while saturation history and core cleaning also seem to have a strong effect on the determination of residual gas saturation. It was found, in some cases, that the residual gas by spontaneous imbibition was unreasonably high. This was attributed to weak wetting conditions of the core (no water pull by imbibition). It is expected that this work will shed some new light on an old, but not-so-well-understood, topic. Introduction When a porous medium is partially or fully saturated with a nonwetting phase, and a wetting phase is allowed to invade the porous medium, the process is called imbibition. For the problem addressed in this work, the nonwetting phase is assumed to be gas, and the wetting phase is assumed to be the aquifer water. If the medium is dry and the water is imbibing, then the imbibition is primary (Swi=0). If the water is already in the medium, the imbibition is secondary (Swi>0). If there is no driving force other than the affinity to wet, the imbibition is spontaneous. If there is any other positive pressure gradient, the imbibition is called forced. Numerous papers have been written on the subject of residual oil saturation from imbibition, but fewer have been prepared on the subject of residual gas saturation from imbibition. The common perception is that many of the principles that cover oil and gas reservoirs are the same. Agarwal1 addressed the relationship between initial and final gas saturation from an empirical perspective. He worked with 320 imbibition experiments and segmented the database to develop curve fits for common rock classifications. Land2 noted that available data seemed to fit very well to an empirical functional form given asEquation 1 In this model, the only free parameter is the maximum observable trapped nonwetting phase saturation corresponding to Sgr (Sgi=1). This expression does not predict residual phase saturation, only how residual saturation scales with initial saturation. Zhou et al.3 studied the effect of wettability, initial water saturation, and aging time on oil recovery by spontaneous imbibition and waterflooding. A correlation between water wetness and oil recovery by waterflooding and spontaneous imbibition was observed. Geffen et al.4 investigated some factors that affect the residual gas saturation, such as flooding rate, static pressure, temperature, sample size, and saturation conditions before flooding. They found that water imbibition on dry-plug experiments was different from waterflooding experiments with connate water. However, they concluded that the residual gas saturation from the two types of experiments was essentially the same. Keelan and Pugh5 concluded that trapped gas saturation existed after gas displacement by wetting-phase imbibition in carbonate reservoirs. Their experiments showed that the trapped gas varied with initial gas in place and that it was a function of rock type. Fishlock et al.6 investigated the residual gas saturation as a function of pressure. They focused on the mobilization of residual gas by blowdown. Apparently, the trapped gas did not become mobile immediately as it expanded. The gas saturation had to increase appreciably to a critical value for gas remobilization. Tang and Morrow7 introduced the effect of composition on the microscopic displacement efficiency of oil recovery by waterflooding and spontaneous imbibition. They concluded that the cation valency was important to crude/oil/rock interactions. Chierici et al.8 tested whether a reliable value of reserves could be obtained from reservoir past-production performance by analyzing results from six gasfield experiments. They concluded that different gas reservoir aquifer systems could show the same pressure performance in response to a given production schedule. Baldwin and Spinler9 investigated residual oil saturation starting from different initial water saturation using magnetic resonance imaging (MRI). They concluded that at low initial water saturation, the presence of a significant waterfront during spontaneous water imbibition indicated that the rate of water transport was less than that of oil. At high initial water saturation, the more uniform saturation change during spontaneous water imbibition indicated that the rate of water transport was greater than that of oil. The pattern of spontaneous imbibition depended on sample wettability, with less effect from frontal movement in less water-wet samples. Pow et al.10 addressed the imbibition of water in fractured gas reservoirs. Field and laboratory information suggested that a large amount of gas was trapped through fast water imbibition through the fractures and premature water breakthrough. The postulation was made that such gas reservoirs would produce this gas if and when the bypassed gas was allowed to flow to the production intervals under capillary-controlled action. The question of whether the rate of imbibition could enhance the production of this trapped gas was raised. Preliminary experiments on full-diameter core pieces showed that the rates of imbibition were extremely slow and that if the different imbibition experiments were performed in full-diameter plugs, the duration of the experiments would be prohibitively long. These experiments formulated the experimental strategy presented in the following sections.
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Stewart, Maria L., and J. Paul Zimmer. "A high fiber cookie made with VERSAFIBE&[trade] 1490 dietary fiber reduces post‐prandial glucose and insulin responses in healthy adults." FASEB Journal 31, S1 (April 2017). http://dx.doi.org/10.1096/fasebj.31.1_supplement.798.6.
Анотація:
VERSAFIBE™ 1490 dietary fiber is a resistant starch type 4 derived from potato, containing 90% total dietary fiber (TDF, AOAC 991.43 method). This low‐viscosity fiber ingredient has many food applications, including snacks, bread, pasta, and cookies. In this double‐blind, randomized, cross‐over study, we compared the glycemic response to two cookies in 28 healthy adults. The test cookie was formulated with VERSAFIBE 1490 dietary fiber and refined wheat flour (24.1 g TDF) and the control cookie was formulated with maltodextrin and refined wheat flour (0.5 g TDF, control). The cookies were matched for total weight, total carbohydrate, sugars, protein, and fat. Subjects were randomly assigned the treatment order. The primary outcome was the two‐hour (baseline to 120 min) intravenous blood glucose incremental area under the curve (iAUC0‐120min). During each 24‐hour study period, subjects consumed a standard evening meal, fasted for 12 hours, and arrived at the study clinic the following morning. Serum glucose, serum insulin, and capillary glucose were measured at 0 min, 15 min, 30 min, 45 min, 60 min, 90 min, 120 min, 180 min and 240 min after cookie consumption. This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki and approved by the Institutional Review Board (IRB Services, Aurora, Ontario). All subjects provided informed consent prior to enrolling in the study. Product perception (sensory evaluation and overall liking) was similar between the two treatments. The VERSAFIBE 1490 dietary fiber cookie reduced the post‐prandial serum glucose iAUC0‐120min by 44% (p = 0.004) and reduced the maximum glucose concentration (Cmax0‐120min) by 8% (p = 0.001) versus the control cookie. Consumption of the VERSAFIBE 1490 dietary fiber cookie resulted in a significant 46% reduction of the post‐prandial serum insulin iAUC0‐120min (p < 0.001) and a 23% reduction in Cmax0‐120min (p = 0.007) versus the control cookie. There was a 48% reduction in the elevation of post‐prandial capillary glucose iAUC0‐120min (p < 0.001) and a 9% decrease in Cmax 0‐120min (p = 0.005) when participants consumed the VERSAFIBE 1490 dietary fiber cookie versus the control cookie. Serum glucose, serum insulin, and capillary glucose values were significantly lower at individual time points when the VERSAFIBE 1490 dietary fiber cookie was consumed versus the control cookie. This study shows that VERSAFIBE 1490 can be incorporated into a cookie and significantly reduce post‐prandial glucose and insulin responses in healthy adults. The consumer perception of the high‐fiber VERSAFIBE 1490 dietary fiber cookie was similar to the low‐fiber control cookie, which demonstrates a practical approach to formulating baked goods with high dietary fiber content.Support or Funding InformationThis study was funded by Ingredion Incorporated, Bridgewater, NJ, USA. Copyright 2016 by Ingredion Incorporated
20
Halder, Amit, Ashish Dhall, and Ashim K. Datta. "Modeling Transport in Porous Media With Phase Change: Applications to Food Processing." Journal of Heat Transfer 133, no. 3 (November 16, 2010). http://dx.doi.org/10.1115/1.4002463.
Анотація:
Fundamental, physics-based modeling of complex food processes is still in the developmental stages. This lack of development can be attributed to complexities in both the material and transport processes. Society has a critical need for automating food processes (both in industry and at home) while improving quality and making food safe. Product, process, and equipment designs in food manufacturing require a more detailed understanding of food processes that is possible only through physics-based modeling. The objectives of this paper are (1) to develop a general multicomponent and multiphase modeling framework that can be used for different thermal food processes and can be implemented in commercially available software (for wider use) and (2) to apply the model to the simulation of deep-fat frying and hamburger cooking processes and validate the results. Treating food material as a porous medium, heat and mass transfer inside such material during its thermal processing is described using equations for mass and energy conservation that include binary diffusion, capillary and convective modes of transport, and physicochemical changes in the solid matrix that include phase changes such as melting of fat and water and evaporation/condensation of water. Evaporation/condensation is considered to be distributed throughout the domain and is described by a novel nonequilibrium formulation whose parameters have been discussed in detail. Two complex food processes, deep-fat frying and contact heating of a hamburger patty, representing a large group of common food thermal processes with similar physics have been implemented using the modeling framework. The predictions are validated with experimental results from the literature. As the food (a porous hygroscopic material) is heated from the surface, a zone of evaporation moves from the surface to the interior. Mass transfer due to the pressure gradient (from evaporation) is significant. As temperature rises, the properties of the solid matrix change and the phases of frozen water and fat become transportable, thus affecting the transport processes significantly. Because the modeling framework is general and formulated in a manner that makes it implementable in commercial software, it can be very useful in computer-aided food manufacturing. Beyond its immediate applicability in food processing, such a comprehensive model can be useful in medicine (for thermal therapies such as laser surgery), soil remediation, nuclear waste treatment, and other fields where heat and mass transfer takes place in porous media with significant evaporation and other phase changes.
21
Ong, Ying Qian, Sakinah Harith, Mohd Razif Shahril, Norshazila Shahidan, and Hermizi Hapidin. "Acute effect of Melon Manis Terengganu peel powder on glycemic response, perceived satiety, and food intake: a randomized, placebo-controlled crossover trial in adults at risk of type 2 diabetes." BMC Nutrition 8, no. 1 (August 8, 2022). http://dx.doi.org/10.1186/s40795-022-00572-1.
Анотація:
Abstract Background Melon Manis Terengganu (MMT) peel has a high dietary fiber content, but there is no data examining its health benefits in adults at risk of type 2 diabetes. The objective of the study was to evaluate whether consumption of MMT peel powder improves glycemic response, satiety, and food intake in adults at risk of type 2 diabetes. Methods An open-label, randomized, placebo-controlled, crossover design trial was conducted among adults (n = 30, ages 18–59 y) at risk of type 2 diabetes. They consumed Formulation 3 (formulated MMT peel powder) [A] and control (glucose) [B] with study breakfast based on randomly assigned treatment sequences (AB, BA) established by Research Randomizer (www.randomizer.org). Capillary blood glucose and perceived satiety were determined at baseline (0 min), 30, 60, 90 and 120 min, followed by a post-intervention food intake measurement. Results The repeated measures analysis of variance (ANOVA) revealed significant time (F = 84.37, p < 0.001, ηp2 = 0.744), condition (F = 22.89, p < 0.001, ηp2 = 0.441), and time*condition effects (F = 24.40, p < 0.001, ηp2 = 0.457) in blood glucose levels. Respondents (n = 30) who consumed Formulation 3 also had a significantly lower blood glucose 2-hour incremental area under the curve (iAUC) of 134.65 ± 44.51 mmol/L*min and maximum concentration (CMax) of 7.20 (7.10, 8.20) mmol/L with relative reduction of 26.8 and 13.3% respectively, when compared with control (p < 0.001). Besides, significantly greater perceived satiety, lower energy and fat intake as well as higher dietary fiber intake were also observed in the intervention group compared with the placebo group (p < 0.05). There were no marked side effects associated with the ingestion of the test products. Conclusions Short-term consumption of formulated MMT peel powder may improve glycemic response, increase perceived satiety and reduce food intake in adults at risk of type 2 diabetes with the potential to be utilized as a functional beverage. Medium-to long-term clinical trial is warranted to determine whether taking this formulated MMT peel powder on a daily basis has an influence on health outcomes. Trial registration ClinicalTrials.gov Identifier: NCT05298111. Registered 28/03/2022.
22
Rahimi-Aghdam, Saeed, Enrico Masoero, Mohammad Rasoolinejad, and Zdeněk P. Bažant. "Century-long expansion of hydrating cement counteracting concrete shrinkage due to humidity drop from selfdesiccation or external drying." Materials and Structures 52, no. 1 (January 24, 2019). http://dx.doi.org/10.1617/s11527-018-1307-8.
Анотація:
Abstract A physically based model for auotgenous shrinkage and swelling of portland cement paste is necessary for computation of long-time hydgrothermal effects in concrete structures. The goal is to propose such a model. As known since 1887, the volume of cement hydration products is slightly smaller than the original volume of cement and water (chemical shrinkage). Nevertheless, this does not imply that the hydration reaction results in contraction of the concrete and cement paste. According to the authors’ recently proposed paradigm, the opposite is true for the entire lifetime of porous cement paste as a whole. The hydration process causes permanent volume expansion of the porous cement paste as a whole, due to the growth of C–S–H shells around anhydrous cement grains which pushes the neighbors apart, while the volume reduction of hydration products contributes to porosity. Additional expansion can happen due to the growth of ettringite and portlandite crystals. On the material scale, the expansion always dominates over the contraction, i.e., the hydration per se is, in the bulk, always and permanently expansive, while the source of all of the observed shrinkage, both autogenous and drying, is the compressive elastic or viscoelastic strain in the solid skeleton caused by a decrease of chemical potential of pore water, along with the associated decrease in pore relative humidity. As a result, the selfdesiccation, shrinkage and swelling can all be predicted from one and the same unified model, in which, furthermore, the low-density and high-density C–S–H are distinguished. A new thermodynamic formulation of unsaturated poromechanics with capillarity and adsorption is presented. The recently formulated local continuum model for calculating the evolution of hydration degree and a new formulation of nonlinear desorption isotherm are important for realistic and efficient finite element analysis of shrinkage and swelling. Comparisons with the existing relevant experimental evidence validate the proposed model.
23
Gayathri, Rajagopal, Karthikeyan Parkav, Vasudevan Kavitha, Nagamuthu Gayathri, Raman Jeevan, Shanmugam Shobana, Vasudevan Sudha, et al. "Glycemic Index of a High Protein and High Fiber Oral Nutritional Supplement Vidaslim®." Medical Research Archives 11, no. 3 (2023). http://dx.doi.org/10.18103/mra.v11i3.3576.
Анотація:
Background: Food products with a low Glycemic index (GI) help control blood glucose levels and may also help reduce body weight. The risk of obesity-related chronic diseases increases with the consumption of refined carbohydrate-rich or a diet with high GI food choices. Vidaslim®, an Oral Nutrition Supplement was formulated by Signutra Inc, with a high protein blend (whey, soy, and casein), dietary Fiber (polydextrose), and several phytonutrients with an attempt to reduce body weight. Aim: To determine the GI of the Vidaslim® in fifteen overweight / obese people aged between 20 and 45 years. Methodology: The study participants consumed the test food, Vidaslim® containing 25 g of available carbohydrate. Participants underwent 3 days of reference food (glucose) testing and 1 day of test food with 2 days of wash-out period. In between capillary blood glucose was measured after overnight fasting at 0, 15, 30, 45, 60, 90, and 120 min after consuming the reference and test food in a random order. The GI was assessed using a validated protocol by FAO and ISO (2010). Following this, the glycemic load (GL) of Vidaslim® was also calculated. Results: Out of 15 participants who completed the study, 3 were removed as statistical outliers (GI > mean ± 2SD), and hence the data was presented for the remaining 12 participants. The mean age of the participants was 28.1±5.4 years, and body mass index (BMI) was 27.2±2.7 kg/m2. Vidaslim® had a low GI value of 21±3.6 (Mean+SD). The GI value was not influenced by age, sex, dietary total calories, protein, fat, carbohydrates, dietary Fiber, and physical activity levels. The Glycemic Load (GL) of Vidaslim® was 4.86 (low GL). Conclusion: The oral nutritional supplement, Vidaslim®, has a low GI and GL value, and hence, could be a suitable healthy supplement for those with obesity and diabetes.
24
Borsoi, Giovanni. "Nanostructured lime-based materials for the conservation of calcareous substrates." Architecture and the Built Environment, 2017. http://dx.doi.org/10.59490/abe.2017.8.1952.
Анотація:
Nanolimes, i.e. dispersions of lime (Ca(OH)2)nanoparticles in alcohol, have been extensively investigated over the last two decades as consolidation products for calcareous substrates. The use of nanolimes for consolidation of mural paintings arises from the lack of effective and compatible consolidants for this type of substrates; the use of nanolimes was later extended also to limestone and lime-based mortars, as an alternative for silica-precursor consolidants (e.g. tetraethoxysilan - TEOS), which had shown to have a limited effectiveness and compatibility with calcareous substrates. Nanolime dispersions are characterized by a very small size of the lime particles, which should provide a proper penetration within the porous network of most building materials. In fact, a homogeneous and in-depth penetration of the consolidant is a crucial requirement when dealing with decayed stones and plasters/renders. The effectiveness of nanolime dispersions reported in literature appears controversial. Some authors observed a proper penetration and moderate consolidating action, whereas others report poor penetration, poor consolidation action and sometimes the formation of a white haze on the treated surface. There is no agreement concerning the factors affecting the transport and deposition of the lime nanoparticles within a porous network, and the causes of the observed drawbacks are not well understood. Therefore, the main research question is: Is nanolime a suitable alternative to silica-precursor consolidants (e.g. TEOS) for the consolidation of calcareous substrates? More specifically, the following research questions can be formulated: – How and up to which extent can the effectiveness and compatibility of nanolime be improved? How can deposition of nanolime in depth be improved and the appearance of a white haze on the surface avoided?– How can nanolime properties be fine-tuned to improve the effectiveness and compatibility of the treatment?– What is the effect of different application methods on the effectiveness of nanolime consolidation? This research investigates and elucidates the behaviour of nanolime products for consolidation of calcareous substrates. Based on the developed knowledge, it proposes and validates a methodology (including solvent modification and application protocol) for improving the consolidation effectiveness of nanolime dispersions, making these a suitable alternative for TEOS products. Firstly, an experimental campaign was carried out in order to understand the penetration and deposition of commercial nanolimes on coarse porous calcareous substrates (Maastricht limestone). The main cause of the poor nanolime deposition in-depth was identified in the back-transport of the nanoparticles towards the drying surface, as a consequence of the high volatility and low kinetic stability of the dispersions. The modification of the nanolime properties, through the optimization of the solvent, appears thus a feasible strategy to improve the in-depth deposition of the lime nanoparticles. New nanolimes were synthetized and dispersed in a selection of solvents conferring different stability and drying rate to the obtained nanolime dispersions. A conceptual model, correlating the properties (i.e. drying rate and kinetic stability) of nanolimes dispersed in different solvents, to the moisture transport behaviour of the substrates to be treated, was conceived. The model was experimentally validated on coarse porous (Maastricht) and fine-porous (Migné) limestones. Experimental results confirmed the predictions of the model that nanolimes dispersed in solvent with lower volatility and stability (e.g. water or butanol) have a good in-depth deposition within coarse porous networks. On the other hand, solvents with higher volatility and guaranteeing higher kinetic stability (e.g. ethanol or isopropanol) to the relative dispersions, should be preferred for substrates with fine porous networks. Fine-tuning the properties of the nanolime dispersion (by modification of the solvent) to the moisture transport behaviour of the substrate, is shown to be a successful strategy for improving in-depth deposition of lime nanoparticles. On the basis of the obtained results, the solvent mixture was further fine-tuned using ethanol-water mixtures. Results proved that ethanol-based nanolime, mixed with a minor amount of water (5%), can provide better nanoparticles in-depth deposition within coarse porous substrates (e.g. Maastricht limestone), when compared to dispersions in pure ethanol. The application procedure of nanolime dispersions was also studied and optimized, this step being a crucial aspect for a successful consolidation; nanolimes were applied both by capillary absorption (method commonly used for laboratory tests) or by nebulization (method widely used in situ) on a coarse porous limestone and a mortar. The research showed that results obtained by application through capillary absorption do not always correspond to those obtained by nebulization. The effectiveness and compatibility of nanolimes with improved properties and a fine-tuned application protocol were finally verified. Fresh and weathered Maastricht limestone, as well as lime-based mortars, were treated. Results showed that nanolime dispersions can guarantee an in-depth consolidation both in laboratory mortar specimens and weathered limestone, with only a moderate alteration of the total porosity and of the moisture transport properties of the investigated substrates. Therefore, nanolime dispersions, provided that they are properly formulated and applied, can be a suitable and compatible alternative to TEOS for the consolidation of coarse porous substrates. This dissertation contributes to define guidelines to support restorers and professionals in the choice and application of nanolime dispersions for consolidation of calcareous substrates.
25
Borsoi, Giovanni. "Nanostructured lime-based materials for the conservation of calcareous substrates." Architecture and the Built Environment, 2017. http://dx.doi.org/10.59490/abe.2017.8.1842.
Анотація:
Nanolimes, i.e. dispersions of lime (Ca(OH)2)nanoparticles in alcohol, have been extensively investigated over the last two decades as consolidation products for calcareous substrates. The use of nanolimes for consolidation of mural paintings arises from the lack of effective and compatible consolidants for this type of substrates; the use of nanolimes was later extended also to limestone and lime-based mortars, as an alternative for silica-precursor consolidants (e.g. tetraethoxysilan - TEOS), which had shown to have a limited effectiveness and compatibility with calcareous substrates. Nanolime dispersions are characterized by a very small size of the lime particles, which should provide a proper penetration within the porous network of most building materials. In fact, a homogeneous and in-depth penetration of the consolidant is a crucial requirement when dealing with decayed stones and plasters/renders. The effectiveness of nanolime dispersions reported in literature appears controversial. Some authors observed a proper penetration and moderate consolidating action, whereas others report poor penetration, poor consolidation action and sometimes the formation of a white haze on the treated surface. There is no agreement concerning the factors affecting the transport and deposition of the lime nanoparticles within a porous network, and the causes of the observed drawbacks are not well understood. Therefore, the main research question is: Is nanolime a suitable alternative to silica-precursor consolidants (e.g. TEOS) for the consolidation of calcareous substrates? More specifically, the following research questions can be formulated: – How and up to which extent can the effectiveness and compatibility of nanolime be improved? How can deposition of nanolime in depth be improved and the appearance of a white haze on the surface avoided? – How can nanolime properties be fine-tuned to improve the effectiveness and compatibility of the treatment? – What is the effect of different application methods on the effectiveness of nanolime consolidation? This research investigates and elucidates the behaviour of nanolime products for consolidation of calcareous substrates. Based on the developed knowledge, it proposes and validates a methodology (including solvent modification and application protocol) for improving the consolidation effectiveness of nanolime dispersions, making these a suitable alternative for TEOS products. Firstly, an experimental campaign was carried out in order to understand the penetration and deposition of commercial nanolimes on coarse porous calcareous substrates (Maastricht limestone). The main cause of the poor nanolime deposition in-depth was identified in the back-transport of the nanoparticles towards the drying surface, as a consequence of the high volatility and low kinetic stability of the dispersions. The modification of the nanolime properties, through the optimization of the solvent, appears thus a feasible strategy to improve the in-depth deposition of the lime nanoparticles. New nanolimes were synthetized and dispersed in a selection of solvents conferring different stability and drying rate to the obtained nanolime dispersions. A conceptual model, correlating the properties (i.e. drying rate and kinetic stability) of nanolimes dispersed in different solvents, to the moisture transport behaviour of the substrates to be treated, was conceived. The model was experimentally validated on coarse porous (Maastricht) and fine-porous (Migné) limestones. Experimental results confirmed the predictions of the model that nanolimes dispersed in solvent with lower volatility and stability (e.g. water or butanol) have a good in-depth deposition within coarse porous networks. On the other hand, solvents with higher volatility and guaranteeing higher kinetic stability (e.g. ethanol or isopropanol) to the relative dispersions, should be preferred for substrates with fine porous networks. Fine-tuning the properties of the nanolime dispersion (by modification of the solvent) to the moisture transport behaviour of the substrate, is shown to be a successful strategy for improving in-depth deposition of lime nanoparticles. On the basis of the obtained results, the solvent mixture was further fine-tuned using ethanol-water mixtures. Results proved that ethanol-based nanolime, mixed with a minor amount of water (5%), can provide better nanoparticles in-depth deposition within coarse porous substrates (e.g. Maastricht limestone), when compared to dispersions in pure ethanol. The application procedure of nanolime dispersions was also studied and optimized, this step being a crucial aspect for a successful consolidation; nanolimes were applied both by capillary absorption (method commonly used for laboratory tests) or by nebulization (method widely used in situ) on a coarse porous limestone and a mortar. The research showed that results obtained by application through capillary absorption do not always correspond to those obtained by nebulization. The effectiveness and compatibility of nanolimes with improved properties and a fine-tuned application protocol were finally verified. Fresh and weathered Maastricht limestone, as well as lime-based mortars, were treated. Results showed that nanolime dispersions can guarantee an in-depth consolidation both in laboratory mortar specimens and weathered limestone, with only a moderate alteration of the total porosity and of the moisture transport properties of the investigated substrates. Therefore, nanolime dispersions, provided that they are properly formulated and applied, can be a suitable and compatible alternative to TEOS for the consolidation of coarse porous substrates. This dissertation contributes to define guidelines to support restorers and professionals in the choice and application of nanolime dispersions for consolidation of calcareous substrates.