Real-time imaging of tunable adenosine 5-triphosphate release from an MCM-41-type mesoporous silica nanosphere-based delivery system

We studied a mesoporous silica nanosphere (MSN) material with tunable release capability for drug delivery applications. We employed luciferase chemiluminescence imaging to investigate the kinetics and mechanism of the adenosine 5-triphosphate (ATP) release with various disulfide-reducing agents as uncapping triggers. ATP molecules were encapsulated within the MSNs by immersing dry nanospheres in aqueous solutions of ATP followed by capping of the mesopores with chemically removable caps, such as cadmium sulfide (CdS) nanoparticles and poly(amido amine) dendrimers (PAMAM), via a disulfide linkage. By varying the chemical nature of the 'cap' and 'trigger' molecules in our MSN system, we discovered that the release profiles could indeed be regulated in a controllable fashion.     

CYCLON: Inexpensive Membership Management for Unstructured P2P Overlays

Unstructured overlays form an important class of peer-to-peer networks, notably when content-based searching is at stake. The construction of these overlays, which is essentially a membership management issue, is crucial. Ideally, the resulting overlays should have low diameter and be resilient to massive node failures, which are both characteristic properties of random graphs. In addition, they should be able to deal with a high node churn (i.e., expect high-frequency membership changes). Inexpensive membership management while retaining random-graph properties is therefore important. In this paper, we describe a novel gossip-based membership management protocol that meets these requirements. Our protocol is shown to construct graphs that have low diameter, low clustering, highly symmetric node degrees, and that are highly resilient to massive node failures. Moreover, we show that the protocol is highly reactive to restoring randomness when a large number of nodes fail.Spyros Voulgaris is a PhD student in the Computer Systems department at the Vrije Universiteit Amsterdam. He received his MSc degree from the University of Michigan, Ann Arbor, and his BSc degree from the University of Patras, Greece. His research involves peer-to-peer systems, epidemic protocols, and ad-hoc networks. He is a scholarship recipient of the Greek State Scholarships Foundation (IKY) and the Alexander Onassis Foundation.Daniela Gavidia is a PhD student in the Computer Systems group at the Vrije Universiteit Amsterdam. She received her MSc degree from the Universiteit van Amsterdam. Her research interests include peer-to-peer systems and ad-hoc networks. Her recent work focuses on information dissemination in ad-hoc environments.Maarten van Steen is professor of Computer Science at the Vrije Universiteit Amsterdam. His research concentrates on large-scale distributed systems, notably content delivery networks and peer-to-peer systems. He is senior member of the IEEE and member of the ACM.     

Cereal bars with soy protein and wheat germ, physicochemical characteristics and texture during the storage

Studies analyzing cereal bars have reported on consumer characteristics and preferences in sensory analyses and on their market growth, however little has been published on their physicochemical data and texture properties. Thus the objective of this research was to provide information about the storage of a cereal bar formulation with high protein and vitamin levels based on soy protein and wheat germ, packaged in 3 different films (A: PET/PEBD; B: PETmet/PEBD; C: PET/PEBD/AL/PEBD), during 6 months under environmental conditions of temperature (25 +/- 2 degrees C) and relative humidity (56%). The moisture content, water activity, pH and total acidity of the cereal bars were determined. The textural measurements accompanied during storage were breaking strength, hardness and cohesiveness. The cereal bars presented variations in water activity (Aw), moisture content and total acidity during storage. The moisture content of the bars tended to increase, which led to a significant (p = 0.05) influence on the texture characteristics of breaking strength and hardness, in the different packaging films tested. The increase in the values for breaking strength (A: 4756,5N; B: 5093,0N; C: 5575,6N) at 45 days of storage was attributed to a possible crystallization of the agglutinating syrup used for the bars. The textured soy protein used in the formulation could also have contributed to this fact due to its hygroscopic character, also interfering in the decrease in the cohesiveness measurements (deformation) with time. The effect of the different barrier properties of the packaging films tested was significant (p < 0.05) in the stability of the cereal bars during storage.     

Microvascular growth, development, and remodeling in the embryonic avian kidney: the interplay between sprouting and intussusceptive angiogenic mechanisms

Embryonic development is associated with extensive vascular growth and remodeling. We used immunohistochemical, light and electron microscopical techniques, as well as vascular casting methods to study the developing chick embryo kidney with special attention to the interplay between sprouting and intussusceptive vascular growth modes. During inauguration at embryonic day 5 (E5), the early mesonephros was characterised by extensive microvascular sprouting. By E7, the vascular growth mode switched to intussusception, which contributed to rapid kidney vasculature growth up to E11, when the first obvious signs of vascular degeneration were evident. The metanephros underwent similar phases of vascular development inaugurating at E8 with numerous capillary sprouts and changing at E13 to intussusceptive growth, which was responsible for vascular amplification and remodeling. A phenomenal finding was that future renal lobules arose as large glomerular tufts, supplied by large vessels, which were split into smaller intralobular feeding and draining vessels with subsequent formation of solitary glomeruli. This glomerular duplication was achieved by intussusception, i.e., by formation of pillars in rows and their successive merging to delineate the vascular entities. Ultimately, the maturation of the vasculature was achieved by intussusceptive pruning and branching remodeling. An interesting finding was that strong VEGF expression was associated with the sprouting phase of angiogenesis while bFGF was upregulated during the phase of intussusceptive microvascular growth. We conclude that microvascular growth and remodeling in avian kidney follows an adroitly crafted pattern, which entails a precise spaciotemporal interplay between sprouting and intussusceptive angiogenic growth modes supported partly by VEGF and bFGF.     

Structural Queries in Electronic Corpora

We present a methodology for automatically constructing structural hyperlinks in electronic technical corpora. A structural hyperlink connects components of a document that have specified structural properties with word-based content similarity. Our approach enables queries that may be posed in terms of keywords, as well as structural segments such as definitions, figures, etc.     

Measurements and thermodynamic modeling of the solubility of squalene in supercritical carbon dioxide

The solubility of squalene in supercritical carbon dioxide (SC-CO₂) was measured and it was analyzed together with the values obtained by Catchpole and von Kamp (1997). The results showed that the experimental values obtained in this work agreed with the order of magnitude of those reported in the literature and correlated well with the Chrastil equation. The thermodynamic modeling using the Peng–Robinson equation of state only correlated well with the experimental values obtained when the critical properties and acentric factor reported by Ruivo et al. (2004) were used. The values predicted for the solubility of squalene in SC-CO₂ using modeling employing the GC-EOS, were only of the same order of magnitude as the experimental values for pressures below 200 bar, and its performance was influenced by the value of the critical hard sphere diameter.     

The effect of grape seed extract or Cistus ladanifer L. on muscle volatile compounds of lambs fed dehydrated lucerne supplemented with oil

Thirty-six Merino Branco lambs were assigned to six dietary treatments: control diet (C) consisting of 90% dehydrated lucerne and 10% wheat bran; control diet with 6% of oil blend (CO); control with 2.5% of grape seed extract (GS); control with 2.5% of grape seed extract and 6% of oil blend (GSO); control with 25% of Cistus ladanifer (an aromatic bush widespread in Portugal; CL); control with 25% of C. ladanifer and 6% of oil blend (CLO). The muscle longissimus dorsi was then subjected to the analysis of volatile compounds (SPME–GC/MS). The CLO diet increased the concentration of heptanal, 3-hydroxy-2-butanone and 2-ethyl-phenol in muscle compared to the CL diet. When lambs received the CL diet, their meat contained lower amounts of 4-heptenal compared to the other treatments. The meat of the GS and GSO lambs contained similar amounts of volatile compounds deriving from lipid oxidation (such as heptanal, 2-nonenal, 4-heptenal and 3-hydroxy-2-butanone). These results indicate that in the presence of grape seed extract, oil supplementation did not enhance the production of lipid-derived volatile compounds. Verbenone and 2,2,6-trimethyl-cyclohexanone were detected only in the meat of the Cistus-fed lambs, suggesting that these compounds could be markers of feeding Cistus-containing diets. Meat volatile compounds profile allowed to discriminate between the lambs receiving C. ladanifer and those not receiving this bush in the diet.     

Robustness of Lactobacillus plantarum starters during daily propagation of wheat flour sourdough type I

This study aimed at investigating the robustness of selected sourdough strains of Lactobacillus plantarum. Seven strains were singly used as sourdough type I starters under daily back-slopping propagation (ten days) using wheat flour. Cell numbers of presumptive lactic acid bacteria varied slightly (median values of 9.13–9.46 log cfu g⁻¹) between and within started sourdoughs, as well as the acidifying activity (median values of 1.24–1.33). After three days also the control sourdough (unstarted) had the same values. As shown by RAPD-PCR analysis, five (DB200, 3DM, G10C3, 12H1 and LP20) out of seven strains maintained elevated cell numbers (ca. 9 log cfu g⁻¹) throughout ten days. The other two strains progressively decreased to less than 5 log cfu g⁻¹. As identified by partial sequencing of 16S rRNA and recA genes, L. plantarum (11 isolates), pediococci (7), Lactobacillus casei (3) and Lactobacillus rossiae (2) dominated the flour microbiota. Monitoring of lactic acid bacteria during sourdough propagation was carried out by culture dependent approach and using PCR-DGGE (Denaturing Gradient Gel Electrophoresis). Except for the sourdough started with L. plantarum LP20, in all other sourdoughs at least one autochthonous strain of L. plantarum emerged. All emerging strains of L. plantarum showed different RAPD-PCR profiles. L. rossiae and Pediococcus pentosaceus were only found in the control and sourdough started with strain 12H1. The characterization of the catabolic profiles of sourdoughs (Biolog System) showed that sourdoughs containing persistent starters behaved similarly and their profiles were clearly differentiated from the others. One persistent strain (DB200) of L. plantarum and Lactobacillus sanfranciscensis LS44, previously shown to be persistent ( Siragusa et al., 2009), were used as the mixed starter to produce a wheat flour sourdough. Both strains cohabited and dominated during ten days of propagation.     

Quantitative GC-ECD Analysis of Halogenated Metabolites: Determination of Surface and Within-Thallus Elatol of Laurencia obtusa

Information on natural concentrations or variability of secondary metabolites in marine organisms may be important both to ecological/evolutionary and applied approaches. A gas chromatographic procedure with an electron capture detector (GC-ECD) was developed to quantify the sesquiterpenoid elatol at the surface and within-thalli of 70 specimens of the red seaweed Laurencia obtusa. The concentration of elatol was highest within-thalli [9.89 mg g⁻¹ of L. obtusa, dry weight (d.w.)], compared to lower values found at the surface [0.006 mg g⁻¹ of L.obtusa (d.w.), or 0.5–10.0 ng cm⁻²]. This method provides a rapid and inexpensive quantification of small quantities of elatol, and probably may also be used to quantify other halogenated compounds usually found in red seaweeds.