Functional and nutritional characteristics of proteins and lipids recovered by isoelectric processing of fish by-products and low-value fish: A review

Several fisheries are over-exploited and may collapse; yet the amounts of fish processing by-products containing muscle proteins and ω-3-rich oil are staggering. The by-products are land-filled, ground and discarded or otherwise diverted from human consumption. Due to the lack of technology to recover proteins and lipids from by-products or low-value species, this tremendous resource is unavailable for human consumption. Isoelectric solubilisation/precipitation (ISP) allows efficient recovery of fish proteins and oil which retain functionality and nutritional value of food products. Isoelectric point (pI) is a pH where protein maintains zero electrostatic charge. At pI, protein–protein hydrophobic attraction overcomes protein–water electrostatic attraction resulting in isoelectric precipitation. Conversely, isoelectric solubilisation occurs at a pH different from pI, whereby protein–water attraction and protein–protein electrostatic repulsion are favoured. Therefore, protein solubility/insolubility is induced by ISP, respectively. Consequently, ISP allows selective protein recovery. Lipids are also recovered during ISP processing. This article reviews recent ISP developments to recover proteins and lipids from by-products and low-value marine species.     

We have always been transgenic

This dialogue concerns the nature of ethical responsibility in contemporary art practice, and its relation to questions of creativity; the role of writing in shaping the perception of transgenic art and related practices; and the problems that may be associated with trusting artists to act with integrity in the unchartered waters of their enthusiastic engagement with genetic technologies.     

Induction of fibrinogen expression in the lung epithelium during Pneumocystis carinii pneumonia

Pneumocystis carinii is an important pulmonary pathogen responsible for morbidity and mortality in patients with AIDS. The acute-phase response (APR), the primary mechanism used by the body to restore homeostasis following infection, is characterized by increased levels of circulating fibrinogen (FBG). Although the liver is the primary site of increased FBG synthesis during the APR, we unexpectedly discovered that FBG is synthesized and secreted by lung alveolar epithelial cells in vitro during an inflammatory stimulus. Therefore, we sought to determine whether lung epithelial cells produce FBG in vivo using animal models of P. carinii pneumonia (PCP). Inflammation was noted by an influx of macrophages to P. carinii-infected alveoli. Northern hybridization revealed that gamma-FBG mRNA increased two- to fivefold in P. carinii-infected lung tissue, while RNA in situ hybridization demonstrated increased levels of gamma-FBG mRNA in the lung epithelium. Immunoelectron microscopy detected lung epithelial cell-specific production of FBG, suggesting induction of a localized inflammatory response resembling the APR. A systemic APR was confirmed by a two- to fivefold upregulation of the levels of hepatic gamma-FBG mRNA in animals with PCP, resulting in a corresponding increase in levels of FBG in plasma. Furthermore, immunoelectron microscopy revealed the presence of FBG at the junction of cell membranes of trophic forms of P. carinii organisms aggregated along the alveolar epithelium. These results implicate FBG in the pathogenesis of PCP in a manner similar to that of the adhesive glycoproteins fibronectin and vitronectin, which are known to participate in intra-alveolar aggregation of organisms and adherence of P. carinii to the lung epithelium.     

The roles of rare earth dispersoids and process

Low cycle fatigue tests were conducted at 482 °C (900 °F) on forgings and extrusions of a rapidly solidified powder metallurgy titanium base alloy with and without rare earth additions. The variables studied were process temperature and heat treatment. Rare earth dispersions reduced fatigue life, and fracture surfaces indicated internal fatigue crack initiation at rare earth particles.     

Glycoprotein A is the immunodominant antigen of Pneumocystis carinii in mice following immunization

A rapid and simple dual enzyme-linked immunosorbent assay was developed to quantitate the relative frequency of monoclonal antibodies produced against Pneumocystis carinii glycoprotein A (gpA) or other antigens of P. carinii after immunization with whole organisms. In BALB/cj mice, P. carinii gpA was clearly the immunodominant antigen, with a quarter of all hybridomas secreting antibody directed against this molecule.     

Furnace atmosphere effects on casting of eutectic superalloys

Control of furnace atmosphere is a key factor in the use of silica-bonded alumina shell molds for the directional solidification of eutectic superalloys reinforced with tantalum monocarbide whiskers. The use of a furnace atmosphere which is simultaneously oxidizing to aluminum in the eutectic alloy and reducing to silica phases in the mold results in the formation of an alumina barrier layerin situ at the metal/mold interface and an absence of silica phases in the mold region adjacent to this barrier layer. The presence of this microstructure permits castings of eutectics at metal temperatures up to 1750°C.     

Residual thermal strains and stresses in organic matrix composite materials

ABSTRACT

Residual strain/stress may arise in organic matrix composite materials due to the intrinsic heterogeneity of their elementary constituents (polymer matrix and fibrous reinforcements), for instance, during material processing, thermal cycling, for harsh in-service conditions. This article illustrates some method to “measure” residual/internal strains/stresses of thermal origin—at both the microscopic and the mesoscopic levels—by inverse analysis of the matrix shrinkage profiles between fibers in unidirectional composite (at the microscopic scale) and the measure of the deflection (curvature) of 0/90 unsymmetric plates (mesoscopic scale). The analysis is carried out by using multiphysical phenomenological models.     

Wet deposition of polychlorinated biphenyls in urban and background areas of the Mid-Atlantic States

Spatial and temporal trends of polychlorinated biphenyl (PCB) concentrations in precipitation were measured at urban and background sites as part of the New Jersey Atmospheric Deposition Network (NJADN). The volume weighted mean concentration (VWM) of sigmaPCBs (sum of PCBs) based on precipitation measurements at three background sites was in the range of 0.30-0.50 ng/L. Concentrations in precipitation at two urban-industrial sites were on average 7-43 times higher than background concentrations. Wet deposition fluxes of sigmaPCBs at the two urbanized sites were 16 +/- 3.4 and 3.9 +/- 0.72 microg/m2-yr, while the background flux was approximately 0.30 microg/m2-yr. On average, 97% of the total atmospheric washout (WT) of PCBs resulted from particle scavenging. The fraction of atmospheric PCBs on particles was the best predictor of atmospheric washout in both urban (log WT = 0.71 (+/- 0.049) log psi + 4.9 (+/- 0.11); r2 = 0.81) and nonurban areas (log W(T) = 0.77 (+/- 0.083) log psi + 5.6 (+/- 0.16); r2 = 0.64). Wet deposition fluxes of sigmaPCBs are of the same order of magnitude as dry-particle deposition fluxes in all land-use regimes.     

A mechanism governing oxidation-assisted low-cycle fatigue of superalloys

A model capable of characterizing oxidation-assisted low-cycle fatigue is described. It involves the following steps. After a few strain cycles, because of creep, a tensile stress develops during the de-straining phase of the cycle. This stress opens cracks present in the material and exposes the surfaces to the atmosphere, causing thermally grown oxide (TGO) growth. Dilatation takes place upon converting the alloy to oxide, with an associated strain rate that induces a compressive growth stress. Thereafter, during the re-straining phase of the cycle, transverse extension of the substrate induces in-plane tension in the TGO, which “pushes” the TGO into the substrate along the crack front. Finite element simulations of this process have been presented that predict crack growth per cycle, da/dN, comparable with experimental measurements. Trends in da/dN with the TGO dilatation rate and the creep strength of the superalloy have been elucidated.