Nondestructive determination of water and protein in surimi by near-infrared spectroscopy

Nondestructive near-infrared spectroscopy (NIRS) between 400 and 1100 nm regions was employed directly on surimi using a surface interactance fibre optic accessory, to investigate the potential of NIRS as a fast method to determine water and protein contents. The reason why NIRS is well suited when assessing the presence of water or protein is due to the specificity of O–H and N–H bindings. At 980 nm only one broad peak in the original spectra can be seen due to the absorption of water since it contained nearly 80% of surimi. Predictive equations were developed using partial least squares (PLS) regression where excellent predictions for protein and water are noticed. Regression coefficients are higher than 0.98, errors are small and RPD value for protein is well over 8 and that for water is very close to it which can be used for any analytical purpose.     

A novel selective nucleoside phosphorylating enzyme from Morganella morganii

A selective nucleoside phosphorylating enzyme was purified to homogeneity from Morganella morganii NCIMB10466 crude extract. The enzyme appeared to consist of six subunits identical in molecular mass (M_r 25,000). It phosphorylated various nucleosides at the 5′-position to produce nucleoside-5′-monophosphates using pyrophosphate as the phosphate source. Energy-rich compounds, such as carbamylphosphate and acetylphosphate, were also very effective phosphate donors. The enzyme also exhibited phosphatase activity, and dephosphorylated various phosphate esters, but had a weak effect on nucleoside-3′-monophosphates. Based on the results of the kinetic study, the enzyme appeared to be an acid phosphatase. Its activity was partly inhibited by sulfhydryl reagents and heavy metal ions, but not by chelating reagents such as EDTA. Using the purified enzyme, 32.6 mM 5′-IMP was synthesized from inosine with a 41% molar yield, but the synthesized 5′-IMP was hydrolyzed back to inosine and phosphate as the reaction time was extended.     

An analytical solution of temperature response in multilayered materials for transient methods

Transient methods, such as those with pulse- or stepwise heating, have often been used to measure thermal diffusivities of various materials including layered materials. The objective of the present study is to derive an analytical solution of the temperature rise in a multilayered material, the front surface of which is subjected to pulse- or stepwise heating. The Laplace transformation has been used to obtain the analytical solution. This solution will enable us to establish the appropriate measurement method for thermophysical properties of the multilayered material. It is also shown that the present solution can be extended to functionally gradient materials (FGM), in which thermophysical properties as well as compositions change continuously.     

The effect of HLA alleles on response to interferon therapy in patients with chronic hepatitis C

The objective of this study was to determine the degree of leukocyte activation, as measured by cytokine release, in circulating blood during experimental extracorporeal circulation. Complete in vitro extracorporeal membrane oxygenation (ECMO) circuits were used, and 9 experiments were performed. Whole blood stored at 37 degrees C was used as the control. Blood samples were withdrawn before the start of perfusion and at 24 h of perfusion. Statistically significant releases of interleukin (IL)-1beta, IL-8, and IL-1 receptor antagonist were observed in the perfusion circuits compared to both the control blood and baseline values. Also, increases in plasma tumor necrosis factor (TNF)alpha and IL-6 were seen after 24 h of perfusion although these changes did not reach statistical significance. These results indicate that extracorporeal circulation induced leukocyte activation and cytokine release. These reactions might, as an additional trauma, deteriorate the situation in an already severely ill patient. A search for methods to counteract this untoward activation seems warranted.     

Two-dimensional diffraction by slits or strips

The two-dimensional diffraction of plane waves by slits or strips whose width and number are arbitrary is investigated by solving integral equations exactly. It is an extension of the diffraction theory by a conducting halfplane, and the solution is obtained by changing the parameter of the original integral equations.     

A quartz crystal microbalance simulation to examine the effect of ultraviolet light treatment on characteristics of polyethylene surface

The effect of ultraviolet light irradiation on the characteristics of the polyethylene (PE) surface was investigated by the quartz crystal microbalance (QCM) technique. The PE film was prepared on the gold electrodes of the QCM by spin-coating from the solution and then was treated by the excimer UV lamp in ambient air. The changes in the hydrophilic properties, moisture adsorption, and water retention of the PE film due to the UV irradiation were determined from the frequency change of the QCM. To evaluate the detergency of the PE film, stearic acid as model oily soil was deposited onto the PE film formed on the QCM by the Langmuir-Blodgett (LB) technique, and was ultrasonically cleaned in aqueous detergent solutions containing ethanol or surfactant. The removal efficiency obtained from the frequency change of the QCM was found to increase considerably after the UV irradiation. From independently determined contact angles and the surface free energy components of the PE film, the free energy change resulting from the penetration of the detergent solution between stearic acid and PE in the zone of contact was calculated. Good relation was found between the removal efficiency and the free energy change, indicating that the increase in the detergency of the PE surface by UV irradiation was explained by surface energetics.     

Relationship between postmortem changes and browning of boiled, dried, and seasoned product made from Japanese common squid (Tedarodes pacificus) mantle muscle

ABSTRACT:  To clarify the process that possibly causes discoloration in boiled, dried, and seasoned squid products ("sakiika" or "ikakun" in Japanese), we investigated the relationship of squid freshness with the rate of browning using the boiled, freeze-dried, and ground squid product model. ATP and its related compounds in Japanese common squid ( Tedarodes pacificus ) decomposed gradually during storage, yielding hypoxanthine and ribose at 24 h postmortem. The browning rate of the model during preservation as revealed by the increase of the b * value showed a high coefficient in the linear regression against ribose content ( R² = 0.767). Only the model made from the squid stored for 24 h postmortem turned brown. These results strongly suggest that ribose produced during storage plays a major role in the browning of dried and seasoned squid products.     

Removal of inorganic mercury and methylmercury from surface waters following coagulation of dissolved organic matter with metal-based salts

The presence of inorganic mercury (IHg) and methylmercury (MeHg) in surface waters is a health concern worldwide. This study assessed the removal potential use of metal-based coagulants as a means to remove both dissolved IHg and MeHg from natural waters and provides information regarding the importance of Hg associations with the dissolved organic matter (DOM) fraction and metal hydroxides. Previous research indicated coagulants were not effective at removing Hg from solution; however these studies used high concentrations of Hg and did not reflect naturally occurring concentrations of Hg. In this study, water collected from an agricultural drain in the Sacramento-San Joaquin Delta was filtered to isolate the dissolved organic matter (DOM) fraction. The DOM was then treated with a range of coagulant doses to determine the efficacy of removing all forms of Hg from solution. Three industrial-grade coagulants were tested: ferric chloride, ferric sulfate, and polyaluminum chloride. Coagulation removed up to 85% of DOM from solution. In the absence of DOM, all three coagulants released IHg into solution, however in the presence of DOM the coagulants removed up to 97% of IHg and 80% of MeHg. Results suggest that the removal of Hg is mediated by DOM-coagulant interactions. There was a preferential association of IHg with the more aromatic, higher molecular weight fraction of DOM but no such relationship was found for MeHg. This study offers new fundamental insights regarding large-scale removal of Hg at environmentally relevant regarding large-scale removal of Hg at environmentally relevant concentrations.