De Values Research Articles

Microwave-assisted extraction and characterization of pectin from citrus fruit wastes for commercial application

Pectin is an essential hydrocolloid widely used as a gelling, thickening, and stabilizing agent in the food, pharmaceutical, and cosmetic industry. In the present study, an effort has been made to extract pectin from Pomelo (Citrus maxima), Kinnow mandarin (Citrus reticulata) and Citron (Citrus medica) peels with microwave-assisted extraction (MAE) technique using organic citric acid. Pectin extracted with MAE was characterized in terms of yield, ash content, pH, solubility, equivalent weight, methoxyl content, anhydrouronic acid content, and degree of esterification. The extraction conditions had significant effects on physicochemical properties. The results showed that the highest amount of pectin (24.19±0.26%) was obtained from Citrus maxima. Based on DE value all pectins were categorized as low methoxy pectin (LMF). Extracted pectins were highly pure based on AUA content. Structural characterization of extracted pectin from three fruit peels by Fourier Transform Infrared (FT-IR) spectroscopy revealed that pectin has functional groups within the 1740–800 cm-1 spectral region. However, pectin extracted in this study can be used in the manufacturing of low sugar foods such as diet jams and jellies.

Improved Scaling Relationships for Seismic Moment and Average Slip of Strike-Slip Earthquakes Incorporating Fault-Slip Rate, Fault Width, and Stress Drop

ABSTRACT We develop a self-consistent scaling model relating magnitude Mw to surface rupture length (LE), surface displacement DE, and rupture width WE, for strike-slip faults. Knowledge of the long-term fault-slip rate SF improves magnitude estimates. Data are collected for 55 ground-rupturing strike-slip earthquakes that have geological estimates of LE, DE, and SF, and geophysical estimates of WE. We begin with the model of Anderson et al. (2017), which uses a closed form equation for the seismic moment of a surface-rupturing strike-slip fault of arbitrary aspect ratio and given stress drop, ΔτC. Using WE estimates does not improve Mw estimates. However, measurements of DE plus the relationship between ΔτC and surface slip provide an alternate approach to study WE. A grid of plausible stress drop and width pairs were used to predict displacement and earthquake magnitude. A likelihood function was computed from within the uncertainty ranges of the corresponding observed Mw and DE values. After maximizing likelihoods over earthquakes in length bins, we found the most likely values of WE for constant stress drop; these depend on the rupture length. The best-fitting model has the surprising form WE∝logLE—a gentle increase in width with rupture length. Residuals from this model are convincingly correlated to the fault-slip rate and also show a weak correlation with the crustal thickness. The resulting model thus supports a constant stress drop for ruptures of all lengths, consistent with teleseismic observation. The approach can be extended to test other observable factors that might improve the predictability of magnitude from a mapped fault for seismic hazard analyses.

Lab-scale and pore-scale study of low-permeability soil diffusional tortuosity

Diffusion coefficients for Na+ was measured in low-permeability samples (diameter of 3 cm and average length of 7 cm) from the deep disposal site of the Siberian Chemical Combine (SCC) using the end-diffusion technique. The direction of diffusion was perpendicular to the direction of bedding. Special equipment was designed and constructed for the experiment. Two types of concentration observations were used. For non-sorbing Na+, EC sensors and the length distribution of sorbed elements were used. The synthetic solution used in the experiments was a model of the low-activity contaminant of the SCC and consisted of NaNO3 (25 g/L) and nitrate compounds of Cs+, Ni2+, Co2+, and Sr2+ (100 mg/L each). The measured values of the effective diffusion coefficients De for Na+ from 1.92 × 10−11 to 1.70 × 10−10 m2/s. The microstructure was studied with X-ray microtomography for the same cores. Image shooting was performed on undisturbed microsamples with a size of 0.913 mm (7003 vox). Spatial correlation analysis was performed after the binarization of each obtained 3-D structure. This analysis showed that the spatial correlation scale of the indicator variogram is considerably smaller than the microsample length. Then, a numerical simulation of the Laplace equation with binary coefficients for each microsample was performed. The results were analysed in the form of a plot of the tortuosity versus the porosity. Pore-scale simulations show a nonlinear decrease in the tortuosity with decreasing porosity. Exponential values in the range between 1.8 and 2.4 were found by fitting this graph with Archie's model. Anisotropic tortuosity is also detected in the horizontal and vertical directions. The diffusion coefficients of non-sorbing Na+ measured in this study agree with those of the pore-scale diffusion simulation of the microtomography data.

Comparison of Sr Transport in Compacted Homoionous Na and Ca Bentonite Using a Planar Source Method Evaluated at Ideal and Non-Ideal Boundary Condition

With the aim to determine the influence of dominant interlayer cation on the sorption and diffusion properties of bentonite, diffusion experiments with Sr on the compacted homoionous Ca- and Na-forms of Czech natural Mg/Ca bentonite using the planar source method were performed. The bentonite was compacted to 1400 kg·m−3, and diffusion experiments lasted 1, 3 or 5 days. Two methods of apparent diffusion coefficient Da determination based on the analytical solution of diffusion equation for ideal boundary conditions in a linear form were compared and applied. The determined Da value for Ca-bentonite was 1.36 times higher than that for Na-bentonite sample. Values of Kd were determined in independent batch sorption experiments and were extrapolated for the conditions of compacted bentonite. In spite of this treatment, the use of Kd values determined by batch sorption experiments on a loose material for the determination of effective diffusion coefficient De values from planar source diffusion experiments proved to be inconsistent with the standard Fickian description of diffusion taking into account only the pore diffusion in compacted bentonite. Discrepancies between Kd and De values were measured in independent experiments, and those that resulted from the evaluation of planar source diffusion experiments could be well explained by the phenomenon of surface diffusion. The obtained values of surface diffusion coefficients Ds were similar for both studied systems, and the predicted value of total effective diffusion coefficient De(tot) describing Sr transport in the Na-bentonite was four times higher than in the Ca-bentonite.

Improving the Cβ Stereoselectivity of l-Threonine Aldolase for the Synthesis of l-threo-4-Methylsulfonylphenylserine by Modulating the Substrate-Binding Pocket To Control the Orientation of the Substrate Entrance.

l-Threonine aldolase from Actinocorallia herbida (AhLTA) is an ideal catalyst for producing l-threo-4-methylsulfonylphenylserine [(2S,3R)-1 b], a key chiral precursor for florfenicol and thiamphenicol. The moderate Cβ stereoselectivity is the main obstacle to the industrial application of AhLTA. To address this issue, a combinatorial active-site saturation test (CAST) together with sequence conservatism analysis was applied to engineer the AhLTA toward improved Cβ stereoselectivity. The optical mutant Y314R could asymmetrically synthesize l-threo-4-methylsulfonylphenylserine with 81 % diastereomeric excess (de), which is 23 % higher than wild-type AhLTA. Molecular dynamic (MD) simulations revealed that the mechanism for the improvement in Cβ stereoselectivity of Y314R is due to the acylamino group of residues Arg314 controlling the orientation of substrate 4-methylsulfonyl benzaldehyde (1 a) in the active pocket by directed interaction with the methylsulfonyl group; this leads to asymmetric synthesis of l-threo-4-methylsulfonylphenylserine. The success in this study demonstrates that direct control of substrates in an active pocket is an attract strategy to address the Cβ stereoselectivity problem of LTA and contribute to the industrial application of LTA.

PSIII-17 Extrusion Enhances Nutrient and Energy Digestibility of Pulse Grain-based Diets Fed to Growing Pigs

Abstract Heat processing may enhance nutrient digestibility of diets based on pulse grains. The objective of this study was to determine nutrient and energy digestibility of extruded lentil-based diets containing either supplemental plant or animal protein source in growing pigs. Two diets were formulated to provide 2.4 Mcal NE/kg and 4.35 g standardized ileal digestible Lys/Mcal NE: 1) soybean meal diet (SBM), containing 50% lentil, 31% wheat, and 12.8% soybean meal; and 2) fish meal diet (FM), containing 40% lentil, 45% wheat, and 10% fish meal. Following mixing, each diet was divided into 2 parts: one part remained mash while the other part was extruded using a single-screw extruder (105°C, 400 rpm, 5 kg water/h). The 2 extruded and 2 non-extruded diets were tested in a 2 × 2 factorial arrangement. Eight ileal-cannulated barrows (32.3 kg) were fed the 4 diets at 2.8 times maintenance DE (110 kcal per kg of BW0.75) for four 9-d periods in a double 4 × 4 Latin square. The FM diets had greater (P < 0.05) AID of DM, GE, and most AA, and ATTD of CP, but lower apparent hindgut fermentation of DM and GE than the SBM diets. The AID of CP and AA were 3.2 and 4.7%-units greater (P < 0.05), respectively, and the ATTD of GE and DE values were 2.1 and 3.1%-units greater (P < 0.05), respectively, for the extruded diets than the non-extruded diets. Interactions between protein source and extrusion were not observed. In conclusion, FM diets had greater ileal digestibility of DM, energy, and AA than SBM diets. Extrusion increased the AID of CP and most AA, and DE value of both plant- and animal-protein diets based on lentil grain, indicating that extrusion can increase the energy and protein value of pulse-grain based diets fed to growing pigs.

Dark Storage of Enhanced Dark-cutting Beef in Nitrite-embedded Packaging Increased Metmyoglobin Formation upon Repackaging

Abstract The objective of this study was to evaluate nitrite-embedded packaging (NEP) and enhancement effects on the color of dark-cutting beef after repackaging into polyvinyl chloride (PVC) for display. From a commercial packing plant, dark-cutting beef strip loins (n = 8; pH = 6.39) and USDA Low Choice beef strip loins (normal-pH, n = 6) were collected. Bisected dark-cutting loins were randomly assigned to nonenhanced dark-cutting (DCN) and enhanced dark-cutting (DCE) with glucono delta-lactone and rosemary. Steaks (1.91 cm) sliced from nonenhanced normal-pH, DCN, and DCE loins were randomly assigned to 3, 6, or 9 d in dark storage, and DCE steaks were packaged in nitrite-embedded packaging (NEP) while normal-pH and DCN steaks packaged in vacuum packaging. At dark storage d of 3, 6, or 9, steaks were repackaged in PVC and displayed for 6 d. The instrumental color was evaluated every 12 h, and metmyoglobin formation was calculated using the ratio of reflectance of 572 nm and 525 nm. Delta E was calculated to determine the change in color over time using the change in L*, a*, and b* values from h 0 to h 12 of display. Data were analyzed using the Mixed Procedure of SAS, and least squares means were considered significant at P < 0.05 and separated using the PDIFF option. Metmyoglobin formation increased (P < 0.05) within 12 h of repackaging DCE steaks held for 3 d and 6 d of dark storage. At h 12 of display, DCE steaks had significantly more metmyoglobin formation than DCN and normal-pH steaks. The DE of DCE steaks was negative, indicating a decline in color after 12 h of display, while the normal-pH and DCN steaks had a positive DE value indicative of improved surface color. Therefore, repackaging DCE steaks resulted in decreased color stability and increased metmyoglobin formation.

PSIII-18 Super Dose Phytase and Carbohydrase Cocktail Enhance Ileal Nutrient and Energy Digestibility of Corn-soybean Diets in Nursery Pigs

Abstract Feed enzymes may ameliorate reduced nutrient and energy digestibility in nursery pigs. The objective was to test effects of super-dosing phytase and fiber-degrading enzymes on digestibility of DM, GE, CP, AA, and Ca. We tested supplementing a super dose (added 1,500 FYT/kg) of phytase (Ronozyme Hi-Phos) with or without carbohydrase cocktail that contained 85 FXU β-xylanase/kg, 587 U/g endo-1,4-β-glucanase, 513 U/g endo-1,3(4)-β-glucanase, 15,000 U/g hemicellulases, and 3,000 U/g pectinases in corn-soybean meal diets in a 2 × 2 factorial arrangement. Diets included 68% corn, 17% SBM, and a basal level of 500 FTU/kg of phytase, and were formulated to contain 2.50 Mcal/kg NE and 5.10 gSID Lys/Mcal NE. Eight ileal-cannulated nursery pigs (initial BW 10 kg) were fed 4 diets at 3.0 × maintenance DE (110 kcal per kg of BW0.75) for four 9-day periods in a double 4 × 4 Latin square. Apparent hindgut fermentation (AHF) was calculated as apparent total tract digestibility (ATTD) minus apparent ileal digestibility (AID). Interactions between super-dosing phytase and carbohydrase cocktail were observed. Supplementing either carbohydrase cocktail or super dose phytase, but not their combination, increased (P < 0.05) diet AID of DM, GE, CP, and most AA by 4–5%-units. Supplementing super dose phytase increased (P < 0.05) AID of P by 16%-units and ATTD of P by 10%-units. Supplementing super dose phytase or carbohydrase cocktail did not affect AID of Ca and ATTD of GE, CP, and Ca, and diet DE value. Supplementing carbohydrase cocktail without super dose phytase decreased (P < 0.05) diet AHF of DM, GE, and CP. In conclusion, dietary inclusion of super dose phytase or carbohydrase cocktail increased ileal digestibility of nutrients in nursery pigs, and thereby reduced protein entering the large intestine. Additive or synergistic effects of carbohydrase cocktail and super dose phytase were not detected.

Nutrient digestibility of extruded canola meal in ileal-cannulated growing pigs and effects of its feeding on diet nutrient digestibility and growth performance in weaned pigs

Canola meal (CM) contains less crude protein (CP) and more fiber and anti-nutritional factors such as glucosinolates than soybean meal (SBM) and consequently has a lower nutrient digestibility. Therefore, processing strategies that may increase the feeding value of CM warrant study. In two experiments, the effects of extrusion of Brassica napus CM on apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA), apparent total tract digestibility (ATTD) of gross energy (GE) in growing pigs, and growth performance and diet digestibility in weaned pigs were assessed. Solvent-extracted CM was extruded using a single-screw extruder at three screw speeds: 250 (CM-250), 350 (CM-350), or 450 (CM-450) rpm. In exp. 1, in a double 4 × 4 Latin square, eight ileal-cannulated barrows (initial body weight [BW], 68.1 kg) were fed corn starch-based diets containing 50% CM or extruded CM. The CM sample contained 43.2% CP, 33.2% total dietary fiber (TDF), and 8.9 µmol of total glucosinolates/g on a dry matter (DM) basis. Extrusion increased (P < 0.05) the AID of CP, reduced (P < 0.05) apparent hindgut fermentation of CP, and decreased (P < 0.05) predicted net energy (NE) value of diets. Extrusion increased diet AID and CM SID of most indispensable AA by 3.1 to 5.3%-units. In exp. 2, 200 weaned pigs (initial BW, 8.3 kg) were fed diets containing 20% SBM, CM, or extruded CM starting 2 wk postweaning for 3 wk. The CM sample contained 42.7% CP, 28.3% TDF, and 5.3 µmol total glucosinolates/g DM. Wheat-based diets provided 2.3 Mcal NE/kg and 5.1 g SID Lys/Mcal NE. Dietary inclusion of extruded CM replacing SBM decreased (P < 0.05) diet ATTD of DM, GE and CP, and DE value. Average daily feed intake, average daily gain (ADG), and gain:feed (G:F) of pigs did not differ between extruded CM and SBM diets and were not affected by extrusion, but increasing extruder screw speed linearly increased (P < 0.05) ADG for day 1 to 7 and G:F for the entire trial. In conclusion, extrusion increased diet AID and CM SID of AA but not DE and predicted NE values of CM. However, increasing extruder speed did not further increase the SID of most of the AA of CM in growing pigs. Dietary inclusion of 20% CM or extruded CM did not affect the growth performance in weaned pigs.

Application of standardised growth curves in quartz OSL dating of lacustrine sediments on the Mongolian Plateau

The standardised growth curves (SGCs) can compensate for the drawbacks of the single-aliquot regenerative-dose (SAR) procedure, such as low utilization of time and instrument in the optically stimulated luminescence (OSL) dating. In this study, 12 sedimentary samples of 6 lakes from the Mongolian Plateau were selected and 90–125 μm coarse-grains quartz was extracted to establish SGCs. The results show that the OSL signals are mainly composed of a fast component, which is applicable for SAR procedure. The difference in the shape of the dose response curves (DRCs) limits the application of the standardised growth curve (SGC) for which the growth curves among the aliquots corrected by the test dose are scattered. The equivalent dose (De) estimated by the global standardised growth curve (gSGC) by the regenerative normalization (re-normalization) method is more consistent with the full SAR procedure, so the gSGC method is suitable for determining the De values on the regional scale of Mongolian Plateau. For different lacustrine sedimentary samples, the De values estimated by full SAR procedure and gSGC method are consistent for the doses of up to ~280 Gy. The discrepancy of growth curves may result from the sensibility changes of inter-cycle in SAR measurement and the recuperation, also we do not exclude the influence of feldspar inclusions.

Simple Moment Analysis for a Kinetic Study of the Chromatographic Behavior of Spherical Particles and Silica Monoliths.

A simple procedure of moment analysis was proposed for a kinetic study of the rate processes in the columns packed with full-porous spherical particles and silica monoliths. Previous chromatographic data measured in reversed-phase HPLC systems using Mightysil and Chromolith columns were analyzed by a simple moment analysis. The surface of the packing materials is chemically modified with octadecyl alkyl ligands. A mixture of methanol and water (80/20, v/v) and alkylbenzene homologous series (C6H5CnH2n+1, n = 0 - 7) were used as the mobile-phase solvent and sample probes, respectively. More detailed information about the experimental conditions is provided in Supporting Information. The values of the intra-stationary phase diffusivity (De) and the surface diffusion coefficient (Ds), derived by the simple moment analysis, were almost the same as those by the conventional moment analysis. The simple moment analysis is effective for quantitative studies of mass transfer in chromatographic systems. The previous chromatographic data were also analyzed by assuming external porosity (εe) as typical values, i.e., 0.40 for spherical particles and 0.70 for silica monoliths. The resulting values of De and Ds were of the same order of magnitude as those derived by using εe experimentally measured. Even if εe is assumed to be typical values, the simple moment analysis is effective for preliminary studies of the mass-transfer kinetics in the columns.

The effect of Dean, Reynolds and Womersley numbers on the flow in a spherical cavity on a curved round pipe. Part 2. The haemodynamics of intracranial aneurysms treated with flow-diverting stents.

The flow in a spherical cavity on a curved round pipe is a canonical flow that describes well the flow inside a sidewall aneurysm on an intracranial artery. Intracranial aneurysms are often treated with a flow-diverting stent (FDS), a low-porosity metal mesh that covers the entrance to the cavity, to reduce blood flow into the aneurysm sac and exclude it from mechanical stresses imposed by the blood flow. Successful treatment is highly dependent on the degree of reduction of flow inside the cavity, and the resulting altered fluid mechanics inside the aneurysm following treatment. Using stereoscopic particle image velocimetry, we characterize the fluid mechanics in a canonical configuration representative of an intracranial aneurysm treated with a FDS: a spherical cavity on the side of a curved round pipe covered with a metal mesh formed by an actual medical FDS. This porous mesh coverage is the focus of Part 2 of the paper, characterizing the effects of parent vessel Re, De and pulsatility, Wo, on the fluid dynamics, compared with the canonical configuration with no impediments to flow into the cavity that is described in Part 1 (Chassagne et al., J. Fluid Mech., vol. 915, 2021, A123). Coverage with a FDS markedly reduces the flow Re in the aneurysmal cavity, creating a viscous-dominated flow environment despite the parent vessel Re > 100. Under steady flow conditions, the topology that forms inside the cavity is shown to be a function of the parent vessel De. At low values of De, flow enters the cavity at the leading edge and remains attached to the wall before exiting at the trailing edge, a novel behaviour that was not found under any conditions of the high-Re, unimpeded cavity flow described in Part 1. Under these conditions, flow in the cavity co-rotates with the direction of the free-stream flow, similar to Stokes flow in a cavity. As De increases, the flow along the leading edge begins to separate, and the recirculation zone grows with increasing De, until, above De ≈ 180, the flow inside the cavity is fully recirculating, counter-rotating with respect to the free-stream flow. Under pulsatile flow conditions, the vortex inside the cavity progresses through the same cycle - switching from attached and co-rotating with the free-stream flow at the beginning of the cycle (low velocity and positive acceleration) to separated and counter-rotating as De reaches a critical value. The location of separation within the harmonic cycle is shown to be a function of both De and Wo. The values of aneurysmal cavity Re based on both the average velocity and the circulation inside the cavity are shown to increase with increasing values of De, while Wo is shown to have little influence on the time-averaged metrics. As De increases, the strength of the secondary flow in the parent vessel grows, due to the inertial instability in the curved pipe, and the flow rate entering the cavity increases. Thus, the effectiveness of FDS treatment to exclude the aneurysmal cavity from the haemodynamic stresses is compromised for aneurysms located on high-curvature arteries, i.e. vessels with high De, and this can be a fluid mechanics criterion to guide treatment selection.

In-vitro efficacy of two spectrophotometer-based shade matching systems for color matching of ceramics after artificial accelerated aging

Objective: The objective of the present invitro study was to verify the efficacy of two spectrophotometer-based shade matching systems for color matching of ceramics after artificial accelerated aging (AAA). Material and Methods: : The ceramics used were porcelain laminated veneers. Seventy standard-shaped discs (thickness x diameter: 0.5 mm x 10 mm) of B1 shades were used. Based upon the type of resin cement used, the specimens were divided into seven groups (10/group). The following light-cured cements were used: RelyX-Veneer (L-RV), Variolink-Veneer (L-VV), and VariolinkEsthetic (L-VE). The dual-cured cements were: RelyX Ultimate (D-RU), RelyX-Unicem (D-RC), and Variolink-Esthetics DC (D-VE). The control group consisted of ceramic only. All specimens were thermocycled in water for 3,500 cycles between 5 o C -55 o C, with dwell times of 30 s in each bath and a transfer time of 10 s between baths. All specimens were thermocycled in water for 3,500 cycles between 5 o C and 55 o C, and color measurement was done using the VITA Easyshade and ColorEye spectrophotometers. Baseline color reading was performed 24-hours after cementation. Differences in color (DE) of EasyShade and ColorEye before and after AAA were determined and compared statistically. Group comparisons were done using the paired t-tests. Level of significance was set at P&lt; 0.05. Results: The mean differences in color (DE) values obtained from EasyShade spectrophotometer for light- and dual-cured cements, were 0.843±0.89 (Lc1), 4.11±0.69 (Lc2) and 0.833±0.47 (Lc3); and 2.22±0.64 (Dc1), 3.37±0.83 (Dc2) and 0.38±0.92 (Dc3), respectively. The mean differences in color (DE) values obtained from ColorEye spectrophotometer for light- and dual-cured cements, were 0.68±0.86 (Lc1), 4.55±0.83 (Lc2) and 2.68±0.26 (Lc3); and 2.06±0.84 (Dc1), 1.8±1.08 (Dc2) and 0.96±0.71 (Dc3), respectively. There was no significant difference in the mean DE values among the groups. Conclusion: The VITA Easyshade and ColorEye shade matching systems are comparable in terms of their efficacy for color matching of cerammics after AAA. Keywords Artificial accelerated aging; Color matching; In vitro; Porcelain veneer; Spectrophotometer.

Strength and leaching behavior of heavy metal contaminated sludge solidified/stabilized by compound binders

Heavy metals contained in sewage sludge may cause potential environmental pollution. In this study, compound binders were used to stabilize and solidify the sludge, which aims to reduce hazard of heavy metals. The strength and leaching behavior of heavy metals from treated sludge was investigated by performing a series of laboratory experiments including the unconfined compressive strength (UCS), the toxicity characteristic leaching procedure (TCLP), the sequential chemical extraction (SCE), and the semi-dynamic leaching test (Semi-DLT). The experimental results showed that the UCS of sludge was significantly improved after stabilization and solidification (S/S) treatment, therefore it can be used as low graded material for landfill. According to the TCLP tests, the selected heavy metals (i.e. Cr, Cu, Zn, Pb, Ni) became more stable under acid conditions in short term. From the SCE tests, some heavy metals were effectively converted into stable form in S/S process. The long term leaching behavior of the heavy metals was also evaluated by the diffusion coefficients (De) and leaching index (L) calculated by the data obtained from the Semi-DLT tests. Low De values showed the S/S treatment is effective for sewage sludge, while the calculated L values also meet the environmental requirement of heavy metal stability.

Évaluation de la dose aux patients lors de l’examen du thorax de face à Abidjan, Côte d’Ivoire

Our study aims to evaluate medical practices in order to reduce patient doses for frontal examination of the thorax in postero-anterior view. Thus, in five (5) radiological rooms of five (5) most frequented hospitals in Abidjan, thirty (30) patients per medical center, meaning a total of one hundred and fifty (150) patients, providing chest examination reports were followed. Using a DAP- meter consisting of an ionization chamber attached to the outlet of the tube and an electrometer, the dose in air (Dair) was measured. Then by calculating the entry dose (De) for each patient was determined. Thus, from the statistical method of the 75th percentile we determine the level of diagnostic references (DRL) in each room as well as in all the rooms of our study. The inlet dose averages (Dem) in each room and in all rooms were calculated. The couples (NRD, Dem) per room expressed in mGy (0.252, 0.226), (0.249, 0.213), (0.164, 0.159), (0.128, 0.117) and (0.234, 0.211) respectively at the CHU of Cocody, CHU of Yopougon, HMA, ICA and PISAM. By comparing the NRD value of De to that of Dem in each radiological room, we found Dem values lower than the NRD. This indicates that the doses are optimized in the rooms of our study, likewise, for all the rooms in Abidjan (0.220, 0.177). However, the average values of the voltage 104.04 kV and the load 4.55 mAs tell us that efforts can be made in the rooms of our study, increasing the voltage and reducing the load, to avoid unneeded doses of X-rays.

Crystal field effect on the magneto caloric properties of the mixed spin-7/2 and spin-3/2 3D-ising ferrimagnet: A Monte Carlo simulation

It has been observed by the Monte Carlo simulation that the Magneto Caloric effect (MCE) of the ferrimagnetic mixed spin-7/2 and spin-3/2 3D Ising system is influenced by the change of crystal field coefficients. The peak value of the magnetic entropy change ΔSP has a second order polynomial dependency on the reduced crystal field coefficient De. This relation is only valid for the low magnetic field and low De values. The inverse of the coefficients of the polynomials has a linear dependency with the 4/3 power of the magnetic field. Full width half maximum (FWHM) of temperature dependence ΔS curve increases with the increment of De. The relative cooling power (RCP) increases with De and at De = 4 a large percentage change of ΔRCP % (~55%) is observed for the reduced field h = 5.

High-resolution portable-OSL analysis of Vegetated Linear Dune construction in the margins of the northwestern Negev dunefield (Israel) during the late Quaternary

Abstract Vegetated Linear Dunes (VLDs) are elongated dunes whose construction is controlled by vegetation and wind. Common in southern hemisphere drylands, they were mainly active in the late Pleistocene. VLDs vertically accumulate sand during elongation episodes and their internal stratigraphy thus serves as a proxy for major periods of strong winds. However, the framework of VLD buildup and elongation is constrained by low-resolution luminescence chronology. To overcome this gap this study applies high-resolution Portable Optically Stimulated Luminescence (POSL) profiling coupled with OSL dating and sedimentology of an exposed VLD section, combined with successive sections along a fluvially truncated downwind elongation trace of the dune at the margin of the stabilized northwestern Negev dunefield, Israel. POSL profiling of the VLD section revealed three statistically distinct stratigraphic units. Winnowing of very fine sand and silt grains can explain a higher ratio between quartz and heavy minerals in the upper VLD unit. This winnowing decreased dose rates and, consequently, reduced bulk POSL luminescence signals and De values in the upper unit. The two upper units of the VLD section date to the Younger Dryas while the basal unit dates to the Heinrich-1 event. OSL ages at the lower unit and at the section bases along the downwind elongation trace of the dune indicate initial elongation during the Heinrich-1 event, and even prior. The study demonstrates that beyond delineating accumulation stages and assigning stratigraphic units, POSL is a sensitive sensor of sedimentological and mineralogical differences within a dune profile, enabling correlation with OSL measurements.

Equilibrium and Kinetics of CO2 Adsorption by Coconut Shell Activated Carbon Impregnated with Sodium Hydroxide

The equilibrium and kinetics of CO2 adsorption at 273 K by coconut-shell activated carbon impregnated with sodium hydroxide (NaOH) was investigated. Based on nitrogen adsorption isotherms, porous properties of the tested activated carbons decreased with the increase of NaOH loading, with the decrease resulting primarily from the reduction of pore space available for nitrogen adsorption. Equilibrium isotherms of CO2 adsorption by activated carbons impregnated with NaOH at 273 K and the pressure up to 100 kPa displayed an initial part of Type I isotherm with most adsorption taking place in micropores in the range of 0.7–0.9 nm by pore-filling mechanisms. The amount of CO2 adsorbed increased with the increase of NaOH loading and passed through a maximum at the optimum NaOH loading of 180 mg/g. The CO2 isotherm data were best fitted with the three-parameter Sips equation, followed by Freundlich and Langmuir equations. The pore diffusion model, characterized by the effective pore diffusivity (De), could well describe the adsorption kinetics of CO2 in activated carbons impregnated with NaOH. The variation of De with the amount of CO2 adsorbed showed three consecutive regions, consisting of a rapid decrease of De for CO2 loading less than 40 mg/g, a relatively constant value of De for the CO2 loading of 40–80 mg/g and a slow decrease of De for the CO2 loading of 80–200 mg/g. The maximum De occurred at the optimum NaOH loading of 180 mg/g, in line with the equilibrium adsorption results. The values of De varied from 1.1 × 10−9 to 5.5 × 10−9 m2/s, which are about four orders of magnitude smaller than the molecular diffusion of CO2 in air. An empirical correlation was developed for predicting the effective pore diffusivity with the amount of CO2 adsorbed and NaOH loading.

Isolation of Pectin from Clementine Peel: A New Approach Based on Green Extracting Agents of Citric Acid/Sodium Citrate Solutions

A new approach to extract pectin from clementine peel using citric acid/sodium citrate solutions (CSS) at different pHs as green extracting agents was proposed. In this study, the effects of extraction temperature (65–85 °C), CSS pH (2–8), and extraction time (1–3 h) on the extraction yield, uronic acid content, and degree of methyl esterification (DE) of the clementine peel pectin (CMP) were systematically evaluated by response surface methodology (RSM). Compared with traditional methods, the CMP extracted by this new approach was of higher pectin yield (19.90–34.94%) and uronic acid content (44.96–65.11%), as well as a wide DE value (11.05–84.71%). These functional properties of CMP were mainly determined by the CSS pH and extraction temperature. In comparison with commercial citrus pectin (CP), the extracted CMPs showed lower protein contents and larger molecular weights. The analysis of monosaccharide compositions showed that the high- and low-methyl-esterified CMPs were dominated by homogalacturonans and rhamnogalacturonan-I, respectively. The structural differences between high- and low-methyl-esterified CMPs were identified by their FTIR spectra. Especially, an excellent gel-forming capacity was found in low-methyl-esterified CMP solutions since their rheological behaviors were highly sensitive to low pH and the presence of Ca2+.

Multi-Method Luminescence Dating of Old Fluvial Sediments from Northern Tian Shan, China

At the eastern tip of Anjihai anticline on the northern piedmont of Tian Shan (northwest China), deformed fluvial deposits have recorded active folding since the Pleistocene, but the absence of accurate ages makes it difficult to evaluate the anticline's shortening rate. Geological studies ascribed the fluvial strata to the early Pleistocene, which poses potential challenges for luminescence dating. In this study, multi-methods luminescence dating was applied to a fluvial sand sample taken from the sandy bed of the deformed basal strata. Single grain post-Infrared Infrared Stimulated Luminescence (pIRIR) and multiple-aliquot-regenerative (MAR) dose along with multiple-elevated-temperature pIRIR (MET-pIRIR) procedures were applied to determine the paleodose of the sample. The methodological uncertainties, such as thermal transfer and initial sensitivity change, were treated by increasing the test dose and performing dose recovery test. With consideration of the potential partial bleaching and anomalous fading, various statistical metrics were applied to the D&lt;sub&gt;e&lt;/sub&gt; values determined by using the single grain pIRIR&lt;sub&gt;225&lt;/sub&gt;, single grain pIRIR&lt;sub&gt;290&lt;/sub&gt; and MAR-MET-pIRIR&lt;sub&gt;290&lt;/sub&gt; signals. The minimum age model (MAM) D&lt;sub&gt;e&lt;/sub&gt; values are 11% – 17% lower than the central age model (CAM) D&lt;sub&gt;e&lt;/sub&gt; values in general, and the MAM D&lt;sub&gt;e&lt;/sub&gt; values determined by the single grain pIRIR procedures are underestimated by more than 40% when compared with those determined by MAR-MET-pIRIR&lt;sub&gt;290&lt;/sub&gt; procedure. The MAM MAR-MET-pIRIR&lt;sub&gt;290&lt;/sub&gt; D&lt;sub&gt;e&lt;/sub&gt; of 811 ± 44 Gy results in a burial age of 284 ka for the basal deformed fluvial strata, which is much younger than the proposed early Pleistocene age.