Airborne ultrasonic application on hot air-drying of pork liver. Intensification of moisture transport and impact on protein solubility

Nowadays, there is increasing interest in developing strategies for the efficient and sustainable use of animal by-products, such as pork liver. In order to stabilize the product, a prior dehydration stage may be required due to its high perishability. The water removal process of pork liver is energy costly and time consuming, which justifies its intensification using novel technologies. In this sense, the aim of this study was to assess the effect of the airborne application of power ultrasound on the hot air-drying of pork liver. For that purpose, drying experiments were carried out at 30, 40, 50, 60 and 70 °C on pork liver cylinders at 2 m·s⁻¹ with (US) and without ultrasonic application (AIR). The drying process was modeled from the diffusion theory and, in the dried pork liver, the protein solubility was analyzed in order to determine the effect of drying on the protein quality. The ultrasound application increased the drying rate, shortening the drying time by up to 40% at 30 °C. The effect of power ultrasound at high temperatures (60 and 70 °C) was of lesser magnitude. Drying at 70 °C involved a noticeable reduction in the protein solubility for dried liver, while the impact of ultrasound application on the solubility was not significant (p > 0.05).     

Electrophoretic measurement of water charge density and ion hydration

Water exchange between bulk water and water-ion complexes will be at equilibrium when the charge density of the complex surface equals the charge density of bulk water, producing a constant radius water-ion complex. This complex will migrate in an electric field at a velocity proportional to the complex radius. CE velocity is the sum of the complex charge-dependent velocity and the buffer electro-osmotic flow. Simultaneous use of both a base (1.07 mM imidazole) and an acid (1.5 mM MOPS) buffer negates EOF at pH 7.4. Electric fields below 300 V/cm (potassium, calcium) and 400 V/cm (magnesium) yield migration velocities with no dehydration of the water-ion complexes. The number of waters per complex increase with the ion charge density: K⁺ 1.90, Ca⁺⁺ 5.90, Mg⁺⁺ 6.59 waters/ion. The charge densities of the complexes are similar: K⁺ 1.24, Ca⁺⁺ 1.43, Mg⁺⁺ 1.21 e/nm², for an average bulk water charge density of 1.29 ± 0.11 (SD) e/nm². The addition of 0.1% Triton increases the number of waters for Mg⁺⁺ to 25.33 and lowers the charge density to 0.497 e/nm². High electric field dehydration shows that calcium will be fully dehydrated at 638.3 V/cm and magnesium fully dehydrated at 925.5 V/cm, which occur at 6.15 and 5.78 nm from the membrane. Dehydrated magnesium will then bind to calcium channels leading to decreased smooth muscle activation.     

Proteomics study of rice embryogenesis: discovery of the embryogenesis-dependent globulins

The plant embryo is the germination center of the seed. How an embryo forms during seed maturation remains unclear, especially in the case of monocotyledonous plants. Generally, the complex processes of embryogenesis result from the action of a coordinated network of genes. Thus, a large-scale survey of changes in protein abundance during embryogenesis is an effective approach to study the molecular events of embryogenesis. In this study, two-dimensional gel electrophoresis (2DE) was applied to separate rice embryo proteins collected during the three phases of embryogenesis: 6 days after pollination (DAP), 12 DAP, and 18 DAP. We then employed matrix-assisted laser desorption-ionization time of flight/time of flight mass spectrometry(MALDI TOF/TOF MS) to identify the phase-dependent differential 2DE spots. A total of 66 spots were discovered to be regulated during embryogenesis, and of these spots, 53 spots were identified. These proteins were further categorized into several functional classes, including storage, embryo development, stress response, glycolysis, and protein metabolism. Intriguingly, the major differential spots originated from three globulins. We further examined the possible mechanism underlying the globulins' multiple forms using Western blotting, proteolysis, and blue native gel electrophoresis techniques and found that the multiple forms of globulins were produced as a result of enhanced proteolysis during embryogenesis, indicating that these globulin forms may serve as chaperone proteins participating in the formation of multiple protein complexes during embryogenesis.     

Effects of transesterification and degradation on properties and structure of polycaprolactone-polylactide copolymers

Ester bonds of biodegradable polymers, such as poly (α-hydroxy esters), synthesized by the coordinated anionic ring opening polymerization (CAROP), are subject to transesterification during synthesis. In this work, a series of poly(?-caprolactone)-poly(l-lactide) (PCL-PLA) block and random copolymers with targeted molar mass of 10,000 Da was synthesized to study the mechanism of transesterification reactions via NMR and MALDI-TOF.Polylactide segments are more vulnerable to transesterification compared to polycaprolactone. As a result, the actual quantity of l-lactide in the polymers was less than the target for all studied copolymers because of the decarboxylation and consequent CO elimination from fragments of macromolecules after transesterification. The presence of decarboxylation during transesterification was confirmed analytically and was reflected in the MALDI-TOF and ¹³C NMR spectra. An analysis of the polymer structure pointed to dehydration reactions that led to the formation of cyclic structures and double bonds with possible crosslinking.     

COORDINATION BINDING MODES FOR POLYMERIC CADMIUM DICARBOXYLATE HYDRATE COMPLEXES

Abstract

Single crystal X-ray crystal diffraction, IR and TGA-DTA data and searches in the Cambridge Structural Database (CSD) have been used to analyze coordination binding modes of Cd(II) in dicarboxylate complexes with anions of different length. The results, discussed in this paper, show that Cd(II) presents a range of coordination geometries. Six, seven and eight coordination with different degrees of departure from regular polyhedra are observed. The length of the ions influences the availability of donor oxygens and induces bidentate, six or four member chelating rings, and monodentate binding, which produces polymerization of different dimensionality.     

掺钕磷酸盐激光玻璃除水工艺

利用反应气氛法除水工艺制备了组成为64P205-5.9A12O3-7.1K2O-19BaO-4.0Nd203(Wt%)的掺钕磷酸盐激光玻璃,研究了O2+POCl3、O2+SOCl2两种除水剂的除水效率及同一除水剂在不同除水时间、除水温度、通气流量下对掺钕磷酸盐激光玻璃荧光寿命的影响.结果表明:POCl3的除水效率优于SOCl2;通气最初阶段除水速率最快,且提高除水温度有利于消除水分,但受熔炼设备和工艺的影响,1 200℃进行除水更为合适;延长除水时间、增大通气流量都有助于提高除水效率;玻璃除水反应效率主要受OH基与除水剂界面反应的影响;荧光寿命随着除水时间的延长而增加,最后趋于一个稳定值;通气流量存在最佳值,实验中通气流量为0.8L/min时较好.     

Investigating the Effects of Caffeine on Phonation

Objective

A core component of vocal hygiene programs is the avoidance of agents that may dry the vocal folds. Clinicians commonly recommend that individuals reduce caffeine intake because of its presumed dehydrating effects on the voice. However, there is little evidence that ingestion of caffeine is detrimental to voice production. The first objective of this study was to evaluate whether caffeine adversely affects voice production. The second objective was to evaluate if caffeine exacerbates the adverse phonatory effects of vocal loading.

Study Design

Prospective, double-blinded, sham-controlled study.

Methods

Sixteen healthy adults participated in two sessions where they consumed caffeine (caffeine concentration = 480 mg) or sham (caffeine concentration = 24 mg) beverages. Voice measures (phonation threshold pressure and perceived phonatory effort) were collected. Subjects then completed a vocal loading challenge and voice measures were obtained again.

Results

There were no significant differences in voice measures between the caffeine and sham conditions. Ingestion of caffeine did not adversely affect voice production (P > 0.05) or exacerbate the detrimental phonatory effects of vocal loading (P > 0.05).

Conclusions

Our findings contribute to emerging knowledge on the effects of caffeine on voice production. Recommendations to completely eliminate caffeine from the diet, as a component of a vocal hygiene program, should be evaluated on an individual basis.     

Dehydration of the Sorel Cement Phase 3Mg(OH)2·MgCl2·8H2O studied by in situ Synchrotron X‐ray Powder Diffraction and Thermal Analyses

Dehydration is an important process which affects the chemical, physical and mechanical properties of materials. This article describes the thermal dehydration and decomposition of the Sorel cement phase 3Mg(OH)₂ · MgCl₂ · 8H₂O, studied by in situ synchrotron X‐ray powder diffraction and thermal analyses. Attention is paid on the determination of the chemical composition and crystal structure of the lower hydrates, identified as the phases 3Mg(OH)₂ · MgCl₂ · 5.4H₂O and 3Mg(OH)₂ · MgCl₂ · 4.6H₂O. The crystal structure of 3Mg(OH)₂ · MgCl₂ · 4.6H₂O is solved and refined by the Rietveld method and a structural model for the 3Mg(OH)₂ · MgCl₂ · 5.4H₂O phase is given. These phases show statistical distribution of water molecules, hydroxide and chloride anions positioned as ligands on the magnesium octahedra. A structural scheme of the temperature induced transformations in the thermal range from 25 to 500 °C is presented.