Nanoparticle-mediated local and remote manipulation of protein aggregation

The local heat delivered by metallic nanoparticles selectively attached to their target can be used as a molecular surgery to safely remove toxic and clogging aggregates. We apply this principle to protein aggregates, in particular to the amyloid beta protein (Abeta) involved in Alzheimer's disease (AD), a neurodegenerative disease where unnaturally folded Abeta proteins self-assemble and deposit forming amyloid fibrils and plaques. We show the possibility to remotely redissolve these deposits and to interfere with their growth, using the local heat dissipated by gold nanoparticles (AuNP) selectively attached to the aggregates and irradiated with low gigahertz electromagnetic fields. Simultaneous tagging and manipulation by AuNP of Abeta at different stages of aggregation allow both, noninvasive exploration and dissolution of molecular aggregates.     

Mercury methylation in the epilithon of boreal shield aquatic ecosystems

Methylation rates by periphyton growing on the rocky shore of a remote boreal shield lake were measured over diurnal cycles at temperatures representative of summer and fall conditions. The measurements were carried out in vitro with natural communities grown on artificial Teflon substrates submerged along the lake's shore for 1-2 years. At temperatures above 20 degrees C, epilithon Hg methylation rates were fast and reached a steady state within 12 h upon exposure to 2 ng L(-1) of inorganic mercury. A variety of inhibitors were used to identify which microorganisms in the epilithic biofilm are responsible for the methylation. The addition of molybdate, which is believed to suppress the activity of sulfate-reducing bacteria, decreased methylmercury production rates by 60% in both light and dark experiments. The prokaryote inhibitor chloramphenicol reduced the methylation rate by 40% only during dark periods whereas an algal inhibitor (DCMU), which suppresses photosynthesis, decreased the methylation rate by 60% during light periods. Results of this study reveal that epilithon communities may be a significant source of MeHg to higher aquatic organisms in lakes and that the integrity of the epilithic biofilm is important for its ability to methylate Hg.     

Utilisation of protein fractions from porcine spleen as technofunctional ingredients in emulsified cooked meat sausages

Spleen is a low commercial value meat by-product from industrial slaughterhouses that is mostly underutilised. In this study, porcine spleens were processed to obtain two protein fractions (i.e. soluble and insoluble extracts in sodium citrate buffer 0.1 m pH 5) and the potential of using them to replace functional ingredients in cooked sausages was assessed. Specifically, a pasteurised insoluble protein extract was used as soy protein replacer in mortadella-type sausages, whereas spray-dried soluble proteins were used instead of sodium caseinate in Frankfurt-type sausages. Both splenic extracts performed well as functional ingredients since no differences in proximate composition, emulsion stability, water-holding capacity or texture were found. The only differences were found in the colour of the sausages containing the soluble protein extract, because of the haem and myoglobin content in this ingredient. The results showed that spleens could be a suitable source of non-allergenic functional proteins for meat products.     

Voltage‐Induced Coercivity Reduction in Nanoporous Alloy Films: A Boost toward Energy‐Efficient Magnetic Actuation

Magnetic data storage and magnetically actuated devices are conventionally controlled by magnetic fields generated using electric currents. This involves significant power dissipation by Joule heating effect. To optimize energy efficiency, manipulation of magnetic information with lower magnetic fields (i.e., lower electric currents) is desirable. This can be accomplished by reducing the coercivity of the actuated material. Here, a drastic reduction of coercivity is observed at room temperature in thick (≈600 nm), nanoporous, electrodeposited Cu–Ni films by simply subjecting them to the action of an electric field. The effect is due to voltage‐induced changes in the magnetic anisotropy. The large surface‐area‐to‐volume ratio and the ultranarrow pore walls of the system allow the whole film, and not only the topmost surface, to effectively contribute to the observed magnetoelectric effect. This waives the stringent “ultrathin‐film requirement” from previous studies, where small voltage‐driven coercivity variations were reported. This observation expands the already wide range of applications of nanoporous materials (hitherto in areas like energy storage or catalysis) and it opens new paradigms in the fields of spintronics, computation, and magnetic actuation in general.     

Anelastic relaxation in high purity molybdenum single crystals at medium temperatures

The internal friction of deformed molybdenum single crystals with two different orientations has been measured in the 300–1300 K temperature range. After annealing to 950 K, a relaxation peak is seen in the 880–840 K range, with a hysteresis between the warming and cooling runs. For higher annealing temperatures, the peak position change to 970 K for the 1 1 0 and 1040 K for the 1 4 9 sample. The influence of a bias stress on the sample relaxation was studied. Possible mechanisms for this relaxation have been considered, and an interaction of dislocations with vacancy type point defects has been proposed.     

Apposition of enkephalin- and neurotensin-immunoreactive neurons by serotonin-immunoreactive varicosities in the rat spinal cord

The descending serotonergic system provides a powerful inhibitory input to the dorsal horn of the spinal cord. Little is known about the chemical identity of the spinal neurons that the serotonergic system innervates, although spinal enkephalinergic neurons are likely candidates. This study investigated the apposition of serotonin-immunoreactive varicosities onto enkephalin- and neurotensin-immunoreactive neurons in the rat lumbosacral spinal cord. Using a double immunofluorescence technique, serotonin-immunoreactive varicosities were observed to abut the soma or proximal dendrites of [Met]enkephalin- and neurotensin-immunoreactive neurons. Nearly 75% of all [Met]enkephalin- and neurotensin-immunoreactive neurons were apposed by serotonin-immunoreactive varicosities in the marginal zone and dorsal gray commissure. In substantia gelatinosa, approximately half of the [Met]enkephalin- and neurotensin-immunoreactive neurons were juxtaposed by serotonin-immunoreactive varicosities. [Met]enkephalin-immunoreactive neurons also were bordered by serotonin-immunoreactive varicosities in the nucleus proprius (65%) and sacral parasympathetic nucleus (75%). The results of this study suggest that the descending serotonergic system mediates nociception via probable contacts with intrinsic enkephalin and neurotensin spinal systems. The mode of action of spinal serotonin on enkephalin and neurotensin neurons may be through "volume" transmission vs synaptic or "wiring" transmission.     

Long-term efficacy of dietary weight loss in sleep apnoea/hypopnoea syndrome

Weight loss is associated with clinical improvement in sleep apnoea/ hypopnoea syndrome (SAHS). The aim of this study was to ascertain whether the therapeutic efficacy of dietary weight loss is maintained in the long-term. From a total of 216 overweight SAHS patients treated by only a weight reduction programme, 24 cured by this method (apnoea/hypopnoea index (AHI) at diagnosis 443+/-27.8, after weight loss 3+/-3.1) were re-evaluated after a mean (+/-SD) period of 94.3+/-27.4 months post-cure. No correlation was found between changes in AHI and body mass index experienced by each patient in the two phases of the study (diagnosis to cure and cure to long-term follow-up), r=0.29, p=0.156, demonstrating a marked intra-individual variability. Six of the 13 patients who maintained their weight presented recurrence of SAHS (AHI 40.5+/-24.1) as did eight of the 11 who had regained weight (AHI 44.3+/-23.). Weight maintenance was more frequent among patients who had continued to attend periodic appointments, 10/11 versus 3/13 (p<0.001). In conclusion, weight-loss efficacy is maintained in the long-term in some sleep apnoea/hypopnoea syndrome patients. This study indicates the need for periodic follow-up of these patients as a reinforcement for weight maintenance and for early detection of the reappearance of sleep apnoea/hypopnoea syndrome.     

Two Triangulation Methods Based on Edge Refinement

In this paper two curvature adaptive methods of surface triangulation are presented. Both methods are based on edge refinement to obtain a triangulation compatible with the curvature requirements. The first method applies an incremental and constrained Delaunay triangulation and uses curvature bounds to determine if an edge of the triangulation is admissible. The second method uses this function also in the edge refinement process, i.e. in the computation of the location of a refining point, and in the re-triangulation needed after the insertion of this refining point. Results are presented, comparing both approaches.     

Green hams electrical impedance spectroscopy (EIS) measures and pastiness prediction of dry cured hams

The objective of this study was to assess the value of electrical impedance spectroscopy (EIS) as a predictor of certain dry-cured ham sensory properties in green hams of different technological meat qualities and processed commercially. Measurements of technological meat quality (weight, ham conformation, subcutaneous fat thickness, pH(45) and pH(u)) and some sensory properties (adhesiveness, hardness, crumbliness, pastiness, fibrousness and saltiness) were carried out on the Biceps femoris (BF) and Semimembranosus (SM) muscles. The electrical parameters, R(o), R(inf), ratio (R(inf)/R(o)), F(c) and α, were obtained with EIS equipment applied to two different regions of the ham at 36 h post mortem (BF and SM). Principal component (PC) analysis was used to describe the relationship between sensory properties and electrical parameters. For BF muscle there were no clear relationships between the electrical parameters and the sensory properties. However, for SM muscle, pastiness was correlated positively with the ratio and F(c) obtained by EIS. None of the electrical parameters obtained by EIS were able to differentiate between groups of hams classified according to their level of pastiness in the BF muscle. However, in the SM muscle, the origin of the pastiness was related to the use of PSE meat and was predicted by the electrical impedance measurements. The EIS prototype correctly detected 69.2 and 56.0% (for SM and BF muscles, respectively) of the problem hams in terms of pastiness. These results could be of use in the selection of the raw material to reduce the incidence of dry-cured hams with defective texture.