Effects of feed composition,protein denaturation and storage of milk serum protein/lactose powders on lactosylation

During whey powder production, the feed is subjected to several heat treatments which can cause lactosylation of proteins. In this study, lactosylation of whey proteins was evaluated in spray-dried powders before and after storage by varying the native protein fraction as well as the serum protein/lactose ratio in the powders. The lactosylation of native α-lactalbumin and β-lactoglobulin in the powders before storage was not affected to a large extent by the protein denaturation or if the feed had been heat treated in a high or low lactose environment. After storage (relative humidity of 23.5%, 30 °C, 25 days), the kinetic of lactosylation tended to increase with increasing native protein fraction and bulk protein content in the powders. An explanation could be that proteins dissolved in the lactose glassy structure might have a lower reactivity, while proteins present in the protein glassy structure with dissolved lactose may display higher lactosylation reactivity.     

Structural Aspects of P2-Type Na0.67Mn0.6Ni0.2Li0.2O2 (MNL) Stabilization by Lithium Defects as a Cathode Material for Sodium-Ion Batteries

A known strategy for improving the properties of layered oxide electrodes in sodium-ion batteries is the partial substitution of transition metals by Li. Herein, the role of Li as a defect and its impact on sodium storage in P2-Na_0.67Mn_0.6Ni_0.2Li_0.2O₂ is discussed. In tandem with electrochemical studies, the electronic and atomic structure are studied using solid-state NMR, operando XRD, and density functional theory (DFT). For the as-synthesized material, Li is located in comparable amounts within the sodium and the transition metal oxide (TMO) layers. Desodiation leads to a redistribution of Li ions within the crystal lattice. During charging, Li ions from the Na layer first migrate to the TMO layer before reversing their course at low Na contents. There is little change in the lattice parameters during charging/discharging, indicating stabilization of the P2 structure. This leads to a solid-solution type storage mechanism (sloping voltage profile) and hence excellent cycle life with a capacity of 110 mAh g^-1 after 100 cycles. In contrast, the Li-free compositions Na_0.67Mn_0.6Ni_0.4O₂ and Na_0.67Mn_0.8Ni_0.2O₂ show phase transitions and a stair-case voltage profile. The capacity is found to originate from mainly Ni³⁺/Ni⁴⁺ and O^2-/O^2-δ redox processes by DFT, although a small contribution from Mn⁴⁺/Mn⁵⁺ to the capacity cannot be excluded.     

In situ observation of synthesized nanoparticles in ultra-dilute aerosols via X-ray scattering

In-air epitaxy of nanostructures (Aerotaxy) has recently emerged as a viable route for fast, large-scale production. In this study, we use small-angle X-ray scattering to perform direct in-flight characterizations of the first step of this process, i.e., the engineered formation of Au and Pt aerosol nanoparticles by spark generation in a flow of N₂ gas. This represents a particular challenge for characterization because the particle density can be extremely low in controlled production. The particles produced are examined during production at operational pressures close to atmospheric conditions and exhibit a lognormal size distribution ranging from 5–100 nm. The Au and Pt particle production and detection are compared. We observe and characterize the nanoparticles at different stages of synthesis and extract the corresponding dominant physical properties, including the average particle diameter and sphericity, as influenced by particle sintering and the presence of aggregates. We observe highly sorted and sintered spherical Au nanoparticles at ultra-dilute concentrations (< 5 × 10⁵ particles/cm³) corresponding to a volume fraction below 3 × 10^–10, which is orders of magnitude below that of previously measured aerosols. We independently confirm an average particle radius of 25 nm via Guinier and Kratky plot analysis. Our study indicates that with high-intensity synchrotron beams and careful consideration of background removal, size and shape information can be obtained for extremely low particle concentrations with industrially relevant narrow size distributions.

     

Effects of breed and age at slaughter on degradation of muscle lipids during processing of dry‐cured hams

Hams from Landrace, Duroc and Hampshire pigs slaughtered at ages 6, 7.5 and 9 months were processed to generate Norwegian Parma‐style hams. Lipid contents and the compositions of fatty acid classes (ΣSFA, ΣMUFA, ΣPUFA) within neutral lipids, phospholipids and free fatty acids were determined. Small differences in lipid degradation and composition of the classes were revealed. However, significant sensory differences related to lipids were observed. Breed was more important than age. Dry‐cured Hampshire hams gave a more intense mature odour that may be associated with higher overall lipid degradation. Unexpectedly, these hams also demonstrated high juiciness and tenderness, which could be related to the melting characteristics of the fat. Dry‐cured Duroc hams showed a higher susceptibility towards rancidity, presumably associated with preferential oxidation of n‐6 fatty acids relative to C18:1 n‐9. Dry‐cured Landrace hams showed the lowest juiciness and tenderness, likely due to their lower fat content (marbling).     

Maternal nutrition and socio-economic status as determinants of birthweight in chronically malnourished African women

The birthweight is the most important determinant of mortality and morbidity in the neonatal period and may have an influence on health in adult life. The high rate of low birthweight in developing countries is therefore a major health problem. Maternal malnutrition is usually assumed to be a causal factor but other environmental factors are also involved. In this study we analysed maternal nutritional and socio-economic factors as determinants of birthweight in term infants from a rural African society characterised by a high rate of chronic malnutrition. Relations of maternal weight, gestational weight gain, parity, socio-economic status and infant sex with birthweight were analysed in 1,477 women and child pairs. The selected women were followed from early pregnancy and had an uncomplicated delivery at term of a living singleton child. The gestational weight gain was 5.6 (SD 6.0) kg and the mean birthweight 2.933 kg (SD 408). Maternal weight, representing the maternal long-term nutritional situation, was the most important independent determinant of birthweight, accounting for 13.0% of the variance in birthweight. The weight gain, representing the short-term nutritional situation, explained only 5.6% of the variance. Birthweight increased by 20 g (CI 18-23) for each kg maternal weight and by 15 g (CI 12-18) for each kg gestational weight gained. The socio-economic difference in birth-weight was 153 g (CI 109-196) 88 of which (CI 48-128) remained unexplained after adjustment for differences in maternal weight, parity and gender. Improved long-term nutritional situation and living conditions seems to be the most important prerequisites to counteract low birthweight in developing countries.     

Role of macrophage overactivation in the development of acute pancreatic injury in rats

PURPOSE: To report quantitative changes in the anterior chamber configuration after small-incision cataract surgery with implantation of a posterior chamber intraocular lens by means of ultrasound biomicroscopy. METHODS: We examined the anterior chamber configuration of 20 eyes of 20 patients before and 3 months after small-incision cataract surgery (phacoemulsification and aspiration plus foldable intraocular lens implantation through a 3.0- to 4.0-mm self-sealing wound) by means of ultrasound biomicroscopy. The following variables were measured: the anterior chamber depth at the center of the cornea, the angle-opening distance 250 microns from the scleral spur (AOD250), the angle-opening distance 500 microns from the scleral spur (AOD500), and the trabecular-iris angle. RESULTS: The anterior chamber depth at the center of the cornea, AOD250, AOD500, and trabecular-iris angle increased significantly after surgery. The preoperative anterior chamber depth at the center of the cornea and trabecular-iris angle were negatively correlated with the differences between the postoperative and preoperative values (P < .01). The preoperative values of all variables examined were negatively correlated with the ratios of the postoperative value to the preoperative value (P < .002). CONCLUSIONS: The present results showed that small-incision cataract surgery significantly deepened the anterior chamber and widened its angle. The more shallow the preoperative anterior chamber was, the greater the postoperative change of the chamber was; and the more narrow the preoperative angle was, the greater the postoperative change of the angle was.     

Titanium and bioactive glass-ceramic coated titanium as materials for keratoprosthesis

The current problem with keratoprosthesis is the ingrowth of corneal or conjunctival epithelium into the anterior chamber. This may lead to infections and extrusion of the prosthesis as well as to the development of retroprosthetic membrane and secondary glaucoma. Glass-ceramic coated and uncoated titanium has been tested as material for the keratoprosthesis to prevent epithelial ingrowth. Twenty-two Supra-Descemet's membrane keratoprostheses were inserted in the eyes of 22 rabbits for 1, 2, 4, 8, or 12 months. The prosthesis had an optic part made of polymethylmetacrylate (PMMA). The support for the optic part and the flange of the prosthesis were made of titanium. Eleven of the prostheses were coated with glass-ceramic. The histological sections of the enucleated eyes were prepared through the central part of the cornea and the prosthesis using a cutting-grinding method. The histological analysis was made on both halves of the implants separately giving two analysis areas in each eye. All 11 titanium prostheses were retained for the time period planned. Two glass-ceramic coated prostheses were lost at 2 and 4 weeks, respectively. This was caused by difficulties at surgery due to a thick coating. These eyes were excluded from the histological analysis. No significant ingrowth of epithelium was seen in 15/18 (83%) and in 16/22 (73%) of the analysed areas of the glass-ceramic coated and titanium prostheses, respectively. Titanium appears to be a suitable material for the keratoprosthesis. The ingrowth of the epithelium may be hindered further by coating the titanium with bioactive glass-ceramic.     

Parabolic dish concentrators approximated by simple surfaces

Two different concentrating mirrors have been constructed that resemble parabolic dish reflectors. Both mirrors are made of slightly curved strips of flat, bendable material. The strips of the most simplified mirror have only large-radius circles and straight lines as boundaries. The necessary equations for making the mirrors are given. Also a simple way to make a stiff, lightweight frame and support for the mirror strips has been developed. Models of the mirrors have been built and successfully used for cooking and baking.     

Effect of specimen size and loading conditions on spalling of concrete

Different qualities of concrete have been fire tested using different geometries of the specimens as well as different load levels and load configurations. The main objective with the study was to examine a test methodology consisting of a full‐scale test and different small scale‐tests for determining the probability of spalling and the amount of spalling of fire exposed concrete structures. A reference specimen was defined as a one‐sided fire exposed slab with the dimensions 1800 × 1200 mm² giving an exposed area of 1500 × 1200 mm². A number of concrete qualities with different probabilities for spalling, were tested using the reference specimen. These tests showed that the reference specimens worked well giving the expected test results. Small specimens were manufactured in different shapes with the same concrete as the one used in the reference tests. These small specimens were tested either at the same time as the reference specimens in the large furnace or afterwards on a small‐scale furnace where the fire exposed surface was 450 × 360 mm². The test results clearly show the increased probability and the increased amount of spalling by using external compressive loading. The results also show that by using pre‐stress through bars or wires the load can be lost due to heating of the bars/wires which results in a decreased amount of spalling. The boundary of the specimen also affects the amount of spalling. The spalling around the edges was in all tests less than the spalling on the central parts of the exposed area. It could also be noted that the spalling did not pass completely through any of the specimens. The reason for this is probably that the water/vapour could migrate out from the unexposed surface of the specimen. Copyright © 2006 John Wiley & Sons, Ltd.