Sucrose Water Solutions Research Articles

Hidden Pitfalls of Using Onion Pollen in Molecular Research

There is little information on the use of pollen in molecular research, despite the increased interest in genome editing by pollen-mediated transformation. This paper presents an essential toolbox of technical procedures and observations for molecular studies on onion (Allium cepa L.) pollen. PCR is a useful tool as an express method to evaluate editing results before pollination. A direct PCR protocol for pollen suspension has been adapted without needing DNA pre-extraction. We showed that the outer layer of lipids known as pollenkitt is a limiting factor for successful PCR on pollen. A simple pre-washing step of pollen suspension was able to eliminate the pollenkitt and enormously affect the PCR results. Additionally, our pollenkitt study helped us develop a simple and effective pollination method using wetted onion pollen grains. Classical manual pollination usually is conducted by intact pollen without wetting. Most existing methods of the editing system delivery into pollen are carried out in a wet medium with consequent drying before pollination, which adversely affects the viability of pollen. The optimal medium for wet pollination was 12% sucrose water solution. Our method of using wetted pollen grains for pollination might be very beneficial for pollen genetic manipulation.

Design and Implementation of a Dual-Region Self-Referencing Fiber-Optic Surface Plasmon Resonance Biosensor.

The need for self-referencing is extremely important in the field of biosensing. In this manuscript, we report on the study, design, and validation of a dual-region self-referencing fiber-optic surface plasmon resonance biosensor. One region is intended to measure and monitor the binding events of the biological sample under test, while the other one is designed to be used as a reference channel to compensate for external factors, such as bulk refractive index modifications and temperature oscillations, that can negatively affect the biomolecular interaction measurement. Two different configurations for the biosensor probe are presented and investigated here, both theoretically and experimentally. First, the theoretical performance of the proposed biosensor probes, in terms of surface plasmon resonance wavelength shift, was simulated using a numerical model. Afterward, they were experimentally validated in sucrose-water solutions and showed a response to refractive index and temperature changes with sensitivities up to 2000 nm/RIU and 1.559 nm/°C, respectively. Finally, an aptamer-based bioassay and a high-resolution melting assay were successfully implemented on the two proposed configurations, demonstrating the feasibility of analyzing the binding events and measuring other external signal modifications simultaneously using the same biosensor probe.

MO420: Effects of Indoxyl Sulfate and Apixaban in Liver Gene Expression

Abstract BACKGROUND AND AIMS Uraemic toxins accumulate in the blood and tissues of patients with chronic kidney disease (CKD). Previous animal studies have shown that chronic kidney disease (CKD) not only alters the elimination of drugs excreted by the kidneys, but it also impacts the metabolism of drugs subject to non-renal clearance, which involves mainly the liver and the gut. The use of apixaban, an oral anticoagulant, has been approved in the USA for dialysis patients. However, the coexistence of thrombotic and haemorrhagic risk in patients with CKD makes dose adjustment difficult. The liver has a major role in drug metabolization. Hepatocytes express high levels of AhR, a ligand-inducible transcription factor that mediates the induction of various liver cytochrome P450 enzymes by xeno and endobiotic. Tryptophan-derived uraemic toxins (TDUT) are AhR agonists. Indoxyl sulfate (IS) is the main TDUT involved in uraemic syndrome. IS increases the expression and activity of P-glycoprotein (P-gp) in the liver. Apixaban metabolism is mediated by P-gp and Cyp3a4 (Cyp3a11 in mice). We aim to study the effect of apixaban and IS in the expression of drug metabolism genes. Our hypothesis is that AhR activation by IS could severely modify drug metabolism during CKD. METHOD C57BL/6J Wild-type mice purchased from The Jackson Laboratory were fed ad libitum with a standard diet. At 10 weeks of age, mice drinking water was substituted with a 5% sucrose water solution with either 0.1% indoxyl sulphate or KCl (control) added at equivalent concentrations. 48-h before sacrifice some mice were gavaged with an apixaban solution (0.6 mg/mL) twice a day with the last dose given 4 h prior to sacrifice. All mice were sacrificed at 11 weeks of age. Liver samples were stored in an RNA-later solution at −20°C. Samples were thawed and lysed in Trizol using the Tissue-Ruptor system (Qiagen). RNA was extracted and purified with chloroform and precipitated with isopropanol. RNA concentration was estimated by spectrophotometry. Gene expression was analysed by q-RT-PCR using Gusb as a housekeeping gene. Apixaban levels were quantified by LC-MS. Kruskal–Wallis followed by a two-stage linear step-up procedure of Benjamini, Krieger and Yekutieli (q < 0.05) was performed using GraphPad Prism 9.2.1. RESULTS Four groups of mice per sex were thus created: WT-KCl, WT-IS, WT-KCl Apix, WT-IS Apix. In the IS/KCl model we observe higher mRNA basal expression of Abcb1a (q = 0.008) and Sult1a1 (q = 0.006) and lower basal expression of Abcg2 (q = 0.0005) in females compared to males when treated with KCl. IS treatment increases Cyp1a2 expression in females (q = 0.0139) and Cyp1a1 in both males (q = 0.0145) and females (q = 0.026). In the IS/KCl-Apix model the same sex-related differences are maintained for Abcb1a (q = 0.0031), Sult1a1 (q = 0.0316) and Abcg2 (q < 0.0001). In males, CYP2e1 expression is increased by apixaban in KCl (q = 0.067) and IS (q = 0.0278) treated mice. Moreover, apixaban counteracts the increased expression of Cyp1a1 induced by IS (q = 0.0177). The expression of Cyp3a11 is augmented in males treated with KCl-apixaban (q = 0.0143), an effect that seems to be reversed by IS (q = 0.0066). In females, apixaban has no effect in gene expression. Apixaban serum concentration is higher in KCl (q = 0.0350) and IS (q = 0.0019) treated females when compared to males. CONCLUSION The effect of IS as an agonist of AhR in the liver is confirmed by the increased expression of Cyp1a1. Apixaban provokes a remarkable increase of Cyp3a11 in male mice, which could lead to higher degradation rates decreasing its activity. IS seems to reverse this effect. This could lead to increased activity of apixaban during CKD which could derive in an increased risk of bleeding. Higher BCRP rates could explain lower rates of apixaban in male serum. Apixaban did not alter gene expression in females. Clinical trials in CKD are generally biased regarding sex (fewer women represented) possibly masking important sex-dependent drug adverse effects. Our results show great differences in basal expression of various genes, confirming the importance to study men and women separately with respect to drug metabolism.

Influence of Cooling Rate on Ice Crystallization and Melting in Sucrose-Water System

The ice crystallization and melting in systems where the equilibrium state is difficult to reach is one of the growing areas in pharmaceutical freeze-drying research. The quality of the final freeze-dried product depends on the parameters of the cooling step, which affect the ice nucleation and growth. In this paper, we present a DSC study of ice crystallization and melting in a sucrose-water system. Using two different types of thermal cycles, we examine the influence of cooling and heating rates on the thermal behavior of sucrose-water solutions with water contents between 50 and 100 wt%.The DSC results show that low cooling rates provide crystallization at higher temperatures and lead to lower amount of non-freezing water. Consequently, the glass transition and ice melting properties observed upon heating depend on the cooling conditions in the preceding step. Based on the experimental results, we investigate the reasons for the existence of the two steps on DSC heating curves in sucrose-water systems: the glass transition step and the onset of ice melting. We show that diffusion of water can be the limiting factor for ice growth and melting in the sucrose-water system when the amorphous phase is in a liquid state. In particular, when the diffusion coefficient drops below 10−14 m2/sec, the ice crystals growth or melting becomes strongly suppressed even above the glass transition temperature. Understanding the diffusion limitations in the sucrose-water system can be used for the optimization of the freeze-drying protocols for proteins and probiotics.

Measurement of the diffusion coefficient in liquids using Fresnel diffraction from a phase step

In this paper, we use Fresnel diffraction from a phase step in transmission to measure the diffusion coefficient in a transparent liquid. A transparent glass plate immersed vertically in a cell containing two diffusing liquids makes a phase step in transmission. When it is illuminated by a parallel beam of light, the diffraction pattern is formed on a screen perpendicular to the direction of the light beam. The diffusion of liquids inside the cell leads to the variation of the diffraction pattern along the edge of the glass plate. The refractive index gradient in the liquids is then obtained by analyzing the diffraction patterns at different times after the beginning of the diffusion process. We then get the diffusion coefficient from the measured gradient. Using this method, we study the diffusion process of the sucrose-water solution and report the diffusion coefficient with a reliable accuracy.

Effect of High Sucrose Diet on Histopathological Indicators Associated With Nonalcoholic Fatty Liver Disease in Male and Female C57bl/6N Mice

Abstract Objectives To evaluate the effect of a high sucrose diet on the histopathological indicators related to NAFLD in male and female mice of the C57bl/6N strain. Methods Forty male and female mice of the C57bl/6N strain were randomly divided into four experimental groups: Control male (CMG) and female groups (CFG) with a standard diet (Rodent Chow) and tap water, as well as sucrose male (SMG) and female groups (SFG) which received standard diet and a 50% sucrose water solution. All the groups were fed ad libitum to one of the two different diets for 20 weeks. After 20 weeks, mice were sacrificed. Blood, hepatic and adipose tissues were collected for analyses. Hepatic tissues were sectioned and stained with hematoxylin and eosin. Samples were examined by light microscopy to analyze liver damage. The non-alcoholic steatohepatitis (NASH) degree was determined according to the histological score system proposed by the clinical research network of NASH. Results In hepatic histological samples of MCG, a normal parenchyma formed by hepatocytes with a conserved architecture was observed, in which the cytoplasm and the nucleus can be appreciated. According to the histological score system of the clinical research network of NASH, it was not considered into any NASH grade. FCG showed few microvesicles in parenchyma, developing grade 1 of NASH, with microvesicular steatosis, not considered pathological. Compared to sucrose groups, in MSG were observed presence of moderate microvesicular steatosis, moderate metabolic stress, and glycogen condensation. No presence of inflammatory infiltrate, inflammation, or granulomas, developing grade 4 of NASH. On the other hand, FSG showed a wide spread of macrovesicular steatosis (zones 1, 2 and 3 of liver acinus), presence of inflammatory infiltrate and granulomas in the liver parenchyma. High metabolic stress in the three zones and glycogen condensation, with the loss of histological architecture, positioning in grade 6 of NASH. Conclusions A high sucrose diet contributed to develop NAFLD in mice of the C57bl/6n strain. MSG showed light to moderate degree of NAFLD, whereas FSG showed a moderate to a high degree of NAFLD (steatosis and NASH) related to sucrose consumption. Funding Sources This work was supported by the Universidad Autónoma de Sinaloa.

Frictionless mobility of submicron particles in model viscid fluid

The mechanism of inter- and intracellular diffusional transport by vesicles in living organisms is poorly understood at the molecular scale. The diffusion of submicron and nanoparticles in dense media has been treated by numerous theoretical models. We face this problem experimentally using Mössbauer spectroscopy. On a characteristic for this method narrow time scale (≈10−7 s), the velocity distribution of 120 nm spherical Fe2O3 particles suspended in a 60% water solution of sucrose was determined by analyzing the 57Fe Mössbauer spectral line profile. The particles usually exhibit classical Brownian motion, but their main diffusion mechanism is related to infrequent (f ≈ 106 s−1) but distant (d ≈ 1 nm) translations. During such movements, the particles experience a minimal friction described by the temporal local viscosity, ηloc ≈ 28 μPa·s.

Assessing the effect of sugar type and form of its intake on selected parameters of carbohydrate-lipid metabolism and plasma atherogenic indices in rats

Over the past 50 years, the average consumption of sugar worldwide has tripled, also the type of consumed sugar has changed. Due to high price of sucrose and its technological disadvantages, high fructose corn syrup (HFCS) has become one of the most commonly used substitutes. The aim of the study was to compare, on the animal model, the effect of sugar type (sucrose vs high fructose corn syrup 55% of fructose) and the sugar form (solid vs fluid and solid) on the chosen parameters of carbohydrate-lipid metabolism. The experiment was carried out on 40 Wistar male rats aged 5 months, fed four isocaloric diets, containing: group I (SUC 15%) fodder with 15% sucrose, group II (HFCS 15%) fodder with 15% HFCS-55%, group III (SUC 7.5%+7.5%) – 7.5% sucrose in solid fodder and 7.5% sucrose water solution, group IV (HFCS 7.5%+7.5%) – 7.5% HFCS-55% in solid fodder and 7.5% HFCS water solution. The effect of HFCS-55 on the parameters of carbohydrate and lipid metabolism was not equivalent of the effect of sucrose. Dietary use of HFCS-55 instead of sucrose causes adverse changes in blood parameters of carbohydrate and lipid metabolism, particularly when provided in beverages, as at comparable weight gains to that of sucrose. More intense changes, manifesting in increased blood levels of glucose, triglycerides and uric acid, as well as increased liver fat content, were observed at simultaneous intake of sweeteners in solid foods and fluids, even with less sugar consumption, compared to solid food only. Dietary use of HFCS-55 causes adverse changes in blood parameters of carbohydrate and lipid metabolism, as at comparable weight gains to that of sucrose. But liquid form of sugar intake is more important insulin resistance and cardiovascular disease risk factor than the sugar type.

Simulating optical coherence tomography for observing nerve activity: A finite difference time domain bi-dimensional model.

We present a finite difference time domain (FDTD) model for computation of A line scans in time domain optical coherence tomography (OCT). The OCT output signal is created using two different simulations for the reference and sample arms, with a successive computation of the interference signal with external software. In this paper we present the model applied to two different samples: a glass rod filled with water-sucrose solution at different concentrations and a peripheral nerve. This work aims to understand to what extent time domain OCT can be used for non-invasive, direct optical monitoring of peripheral nerve activity.

Numerical simulation of unsteady triple diffusive mixed convection in NaCl-water and Sucrose-water solutions

The consequences of the presence of triple diffusive phenomenon on mixed convection from a continuously moving vertical plate are investigated in this paper under variations in time. The behavior of aqueous solutions, such as NaCl-water and Sucrose-water, are modelled and analyzed via a coupled system of nonlinear partial differential equations which are transformed into a dimensionless coupled system of nonlinear partial differential equations with the aid of non-similar transformations. The Quasi-linearization technique in association with the implicit finite difference scheme is employed to obtain non-similar solutions. The graphs acquired for momentum, thermal and species concentration fields involving the effects of the Richardson number, velocity ratio parameter, ratio of buoyancy parameter and Schmidt number of both solutal components have been depicted in a manner which assists in providing a physical interpretation of the results. The graphical interpretations for the skin-friction coefficient, Nusselt number and Sherwood number for both the aqueous solutions are also scrutinized and are discussed with proper physical explanations.

New method to Proboscis Extension Reflex to the assessment of gustatory responses for stingless bees

The proboscis extension reflex (PER) applied to restrained individuals is an important method to assess the sucrose responsiveness under laboratory conditions. Several authors have used the PER bioassay to assess behavioral effects of pesticides. A lot of them reported the difficult to use this method with non-Apis bees showing that this basic technique cannot be applied for all bees. The aim of this study was to evaluate the sucrose responsiveness of two brazilian stingless bees, Melipona scutellaris and Scaptotrigona postica using two different protocols: the traditional one and the new one where bees have free movements. In both cases, the bees were anesthetized (freezing) and inserted into plastic tubes with the tip cut out. After a starvation period were offered an increasing concentration of sucrose-water solution (w/v). Between the solutions, were offered water. With the traditional method, the sucrose responsiveness were observed only in M. scutellaris bees (12.5% of tested bees) in just one sucrose concentration (75%). Using the methodology with free movements, both species showed sucrose responsiveness in all concentrations (25%, 50% and 75%) tested. The number of M. scutellaris bees that had sucrose response ranged from 53.7% to 76.2 % depending on the sucrose concentration. And the number of S. postica ranged from 54% to 79%. These results showed that using the methodology with free movements the sucrose responsiveness can be assessment non-Apis bees.

Degradation of Phenolic Compounds in Aqueous Sucrose Solutions by Ozonation

ABSTRACTThe sugar industry is concerned with color formation due to the oxidation of phenolic compounds in the presence of carbohydrates. In this study, we investigated the ozonation of a mixture of five phenolic compounds in water and aqueous sucrose solution: p-coumaric (p-COU), caffeic (CAF), syringic (SYR), and chlorogenic (CHO) acids, as well as the flavonoid quercetin (QUE). The experiments were carried out in a 3-L glass reactor with magnetic stirring and a diffuser plate at the bottom to feed the ozone-oxygen gas mixture. Initial solution concentrations of 5 mg L−1 of each acid, 15 mg L−1 of quercetin, and 40 g L−1 of sucrose were used. The degradation of phenolic compounds followed apparent first-order kinetics, with rate constants and percent removals decreasing in the presence of sucrose. In water, average consumed ozone dosages of 10.4 and 18.7 mg L−1 were necessary for 50% and 90% removals, respectively, for CHO, CAF, and p-COU; for QUE they were slightly higher (13.9 and 20.5 mg L−1, respectively). At a consumed dosage of 20.8 mg O3 L−1, more than 99% removal was obtained for CHO, CAF, and p-COU, while 96.2% was achieved for SYR. In contrast, QUE revealed to be more recalcitrant during ozonation in the absence of sucrose, with only 70% removal at the highest consumed O3 dosage. The consumed ozone dosages for 50% and 90% removals were higher for CHO, CAF, and p-COU in aqueous sucrose solution, which may impact ozone consumption during real sugarcane juice treatment. Sucrose and t-butanol were the main influential parameters that significantly affected the total amount of phenolic compounds degraded.

An acetone-based phantom for quantitative diffusion MRI.

To propose and evaluate an acetone-D2 O phantom that has an extended range of apparent diffusion coefficient (ADC) for quantitative diffusion magnetic resonance imaging (MRI), as well as to compare its properties to previously described water-based phantoms. The proposed acetone-D2 O, and previously described sucrose water solution and polyvinylpyrrolidone (PVP) water solution phantoms, were constructed in a number of concentrations between 0% and 50%. At 1.5T field strength, diffusion-weighted MR spectroscopy (DW-MRS), based on a point-resolved spectroscopy (PRESS) acquisition, nondiffusion-weighted stimulated echo acquisition mode (STEAM)-MRS, and diffusion-weighted echo-planar imaging (DW-EPI) were used to evaluate each phantom. The MR spectra, diffusion-weighted signal decay pattern, tunability of ADC, and ADC range of each phantom were all evaluated. When placed in an ice-water bath, all phantoms provided desirable signal properties, including single-peak signal with Gaussian diffusion and tunable ADC. At 0°C, however, water-based phantoms had ADC limited to less than 1.1·10-3 mm2 ·s-1 (0.2-1.1·10-3 mm2 ·s-1 ), while the proposed acetone-based phantom had ADC values spanning a wider range (0.6-3.5·10-3 mm2 ·s-1 ). The proposed acetone-D2 O phantom provided desirable signal properties over a wide range of ADCs with temperature controlled using an ice-water bath. 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1683-1692.

Diffusion coefficients of organic molecules in sucrose–water solutions and comparison with Stokes–Einstein predictions

Abstract. The diffusion coefficients of organic species in secondary organic aerosol (SOA) particles are needed to predict the growth and reactivity of these particles in the atmosphere. Previously, viscosity measurements, along with the Stokes–Einstein relation, have been used to estimate the diffusion rates of organics within SOA particles or proxies of SOA particles. To test the Stokes–Einstein relation, we have measured the diffusion coefficients of three fluorescent organic dyes (fluorescein, rhodamine 6G and calcein) within sucrose–water solutions with varying water activity. Sucrose–water solutions were used as a proxy for SOA material found in the atmosphere. Diffusion coefficients were measured using fluorescence recovery after photobleaching. For the three dyes studied, the diffusion coefficients vary by 4–5 orders of magnitude as the water activity varied from 0.38 to 0.80, illustrating the sensitivity of the diffusion coefficients to the water content in the matrix. At the lowest water activity studied (0.38), the average diffusion coefficients were 1.9 × 10−13, 1.5 × 10−14 and 7.7 × 10−14 cm2 s−1 for fluorescein, rhodamine 6G and calcein, respectively. The measured diffusion coefficients were compared with predictions made using literature viscosities and the Stokes–Einstein relation. We found that at water activity ≥ 0.6 (which corresponds to a viscosity of ≤ 360 Pa s and Tg∕T ≤ 0.81), predicted diffusion rates agreed with measured diffusion rates within the experimental uncertainty (Tg represents the glass transition temperature and T is the temperature of the measurements). When the water activity was 0.38 (which corresponds to a viscosity of 3.3 × 106 Pa s and a Tg∕T of 0.94), the Stokes–Einstein relation underpredicted the diffusion coefficients of fluorescein, rhodamine 6G and calcein by a factor of 118 (minimum of 10 and maximum of 977), a factor of 17 (minimum of 3 and maximum of 104) and a factor of 70 (minimum of 8 and maximum of 494), respectively. This disagreement is significantly smaller than the disagreement observed when comparing measured and predicted diffusion coefficients of water in sucrose–water mixtures.

Analytical modelling of electrical impedance based adulterant sensor for aqueous sucrose solutions

An analytical model is developed to describe the dielectric behaviour of pure DI water-sucrose solution in which sodium carbonate (Na2CO3) is added as an adulterant. Relative impact of constituent dipoles has been emphasized and multi-body dipolar interactions have been explicitly considered for a comprehensive analysis of such a system in thermal equilibrium. The theoretical model is verified with experimental data obtained from the impedance and capacitance based spectroscopic measurements. The impedance and capacitance of DI water-sucrose solution are observed to vary in a quasi-oscillatory nature with different sucrose content in it. However, such variation shows a decreasing trend and linear nature for a minimum of 1% adulterant content. The system impedance decreases and capacitance increases with increasing adulterant wt% for a given sucrose concentration. For the 0% of adulterant in the solution with varying sucrose content, the impedance and capacitance have varied from 140.12kΩ to 236.17kΩ and 40.7pF to 44.2pF, respectively. However, such values change from 111Ω to 157kΩ and 42.5pF to 72μF for the adulterant content up to 5%.

Using optical trap to measure the refractive index of a single animal virus in culture fluid with high precision.

The refractive index (RI) is a fundamental parameter of materials that can be used to distinguish and sort materials of different nature. Although the RI of a virus is required for many optics-based biosensing applications, RIs of animal viruses have never been measured. Here we have developed a technique that can measure the RI of individual viruses in aqueous media with high precision. This technique is based on optical trapping of single virions and works by relating the size and RI of a single virus to the stiffness of an optical trap. We have derived an analytic expression to quantitatively describe the optical trapping of these particles. We have validated this equation using nanoparticles of known RI, and measured the RI of individual human immunodeficiency viruses type-1, which yielded a value of 1.42 at 830 nm with less than 2% coefficient of variation. This value is much lower than the RI typically assumed for viruses, but very close to that of 2.0 M sucrose solution in water. To the best of our knowledge, this is the first report on the experimental measurement of the RI for a single animal virus in aqueous media. This technique does not require prior knowledge on the diameter of the nanoparticles, and can be applied to other viruses or nanoparticles for accurate measurement of RI that is critical for the label-free detection of these particles in various settings.

The use of the scanning electron microscope (SEM) to reconstruct the ultrastructure of sporoderm

Scanning electron microscope (SEM) data can help in the interpretation of transmission electron microscope (TEM) ultrathin sections and reconstruction of the three-dimensional inner structure of large palynological objects like megaspores. For a SEM study of the inner structure of fossil megaspores, we tried three variants of embedding media: a water solution of glycerine and gum arabic, a water solution of sucrose and polyvinylpyrrolidone, and a mixture of epoxy resins. Semithin sections of fossil megaspores were made, the embedding medium was removed from the sections and they were observed under SEM. Epoxy mixture as an embedding medium and Maxwell's solution as a solvent turned out to be the most appropriate for our purposes. The most suitable way of processing is to embed the object, cut it by turns in semithin and ultrathin sections, and study them with SEM and TEM correspondingly. A combination of SEM and TEM data results in a more profound reconstruction of the inner structure of sporoderms. We used as test objects dispersed megaspores of a supposed lycopsid affinity identified as Maexisporites rugulaeferus Karasev et Turnau 2015 and Otynisporites tuberculatus Fuglewicz 1977. The materials studied are from the Lower Triassic and Upper Permian of the Russian Platform.

The Use of Index-Matched Beads in Optical Particle Counters.

In this paper, we demonstrate the use of 2-pyridinemethanol (2P) aqueous solutions as a refractive index matching liquid. The high refractive index and low viscosity of 2P-water mixtures enables refractive index matching of beads that cannot be index matched with glycerol-water or sucrose-water solutions, such as silica beads that have the refractive index of bulk fused silica or of polymethylmethacrylate beads. Suspensions of beads in a nearly index-matching liquid are a useful tool to understand the response of particle counting instruments to particles of low optical contrast, such as aggregated protein particles. Data from flow imaging and light obscuration instruments are presented for bead diameters ranging from 6 µm to 69 µm, in a matrix liquid spanning the point of matched refractive index.

Optimisation of mass transfer kinetics during osmotic dehydration of pork meat cubes in complex osmotic solution

This paper presents the effects of different process temperature (20, 35 and 50 ?C), immersion time (1, 3 and 5 hours) and the concentration of sugar beet molasses + NaCl + sucrose water solution on osmotic dehydration of pork meat (M. triceps brachii) cubes, shaped 1 x 1 x 1 cm, at atmospheric pressure. The main objective was to examine the influence of different parameters on the mass transfer kinetics during osmotic treatment. The observed system?s responses were: water loss, solid gain, and water activity. The optimum osmotic conditions (temperature of 40 ?C, treatment time of 4.1 h and concentration 67 %), were determined using response surface method, by superimposing the contour plots of each process variable, and the responses were: water loss=0.46, solid gain=0.15, and water activity=0.79. Transport coefficients, for both solids and water transfer and energy of activation for all samples were also determined.

Cubic - Inverted Hexagonal Phase Transition Kinetics in Monoolein-Sucrose Mixtures

Sugars play key roles in the biology, yet much remains unknown about their interactions with lipids. In particular, we examine the effect of different concentrations of sucrose-water solutions on the cubic - inverted hexagonal transition in monoolein. Using DSC (differential scanning calorimetry), we ramp the temperature up and down through the transition and measure the ramp-rate dependence of the heating and cooling hysteresis. Sucrose has a marked effect on the location of the cubic- inverted hexagonal phase transition temperature, dropping it by about 20°C per molal of sucrose concentration. A strong asymmetry is seen in the kinetics, with the hysteresis in the cooling direction being roughly twice that in the heating direction. This is in contrast to the heating and cooling symmetry in the lamellar- inverted hexagonal transition seen in phospholipids. Sucrose also dramatically increases the hysteresis and the effect is most pronounced at slow temperature ramps. When cooling at a rate of 0.01°C/s, monoolein in a 0.5 molal solution of sucrose exhibits a hysteresis of 1.7°C; monoolein in a 3.0 molal solution shows a hysteresis of 7°C. Avrami exponents for cooling fall in the range of 2.0 - 2.5; for heating, they range from 1 - 3, with the higher exponents seen at slower ramp rates and higher sucrose concentrations.