Alkaline degradation of invert sugar from molasses

Sugar beet and sugar cane molasses have been shown to be suitable starting materials for producing de-icer preparations. The sucrose in the molasses is hydrolyzed to glucose and fructose by invertase. The reducing sugars are then degraded by NaOH, the alkali being neutralized by the sugar acids produced, resulting in an increase of the ionic strength and consequently depression of the freezing point of the resulting solution. For the preparation of de-icers, the desired freezing point depression to a temperature of less than about -20 degrees C can be achieved by adjusting the amount and concentration of the alkali metal hydroxide used. The resulting products are biodegradable and eliminate the corrosive effects associated with the use of conventional chloride salts. Degradation of invert sugar by NaOH has been achieved without an external heat source. The reaction products showed the same freezing point depression as seen in the degradation products from pure glucose.     

Spontaneous in vitro formation of supramolecular beta-amyloid structures, "betaamy balls", by beta-amyloid 1-40 peptide.

The concentration of beta-amyloid peptide (Abeta), x-42 or x-40 amino acids long, increases in brain with the progression Alzheimer's disease (AD). These peptides are deposited extracellularly as highly insoluble fibrils that form densities of amyloid plaques. Abeta fibrillization is a complex polymerization process preceded by the formation of oligomeric and prefibrillar Abeta intermediates. In some of our in vitro studies, in which the kinetics of intermediate steps of fibril formation were examined, we used concentrations of synthetic Abeta that exceed what is normally employed in fibrillization studies, 300-600 microM. At these concentrations, in a cell free system and under physiological conditions, Abeta 1-40 peptide (Abeta40) forms fibrils that spontaneously assemble into clearly defined spheres, "betaamy balls", with diameters of approximately 20-200 microm. These supramolecular structures show weak birefringence with Congo red staining and high stability with prolonged incubation times (at least 2 weeks) at 30 degrees C, freezing, and dilution in H(2)O. At 600 microM, they are detected after incubation for approximately 20 h. Abeta peptide 1-42 (Abeta42) lacks the ability to form betaamy balls but accelerates Abeta40 betaamy ball formation at low stoichiometric levels (1:20 Abeta42:Abeta40 ratio). Abeta42 levels above this (=10-50% w/w) impede Abeta40 betaamy ball formation. Using light (LM) and electron microscopy (EM), this study examines the gross morphology and ultrastructure of Abeta40 betaamy balls and their time course of formation, in the absence and presence of Abeta42, along with some stability measures. As spheres of a misfolded protein, betaamy balls resemble both AD Abeta senile plaques and neuronal inclusion bodies associated with other neurodegenerative diseases.     

Biotherapeutic formulation factors affecting metal leachables from stainless steel studied by design of experiments

Trace amounts of metals are inevitably present in biotherapeutic products. They can arise from various sources. The impact of common formulation factors such as protein concentration, antioxidant, metal chelator concentration and type, surfactant, pH, and contact time with stainless steel on metal leachables was investigated by a design of experiments approach. Three major metal leachables, iron, chromium, and nickel were monitored by inductively coupled plasma-mass spectrometry. It was observed that among all the tested factors, contact time, metal chelator concentration, and protein concentration were statistically significant factors with higher temperature resulting in higher levels of leached metals. Within a pH range of 5.5–6.5, solution pH played a minor role for chromium leaching at 25°C. No statistically significant difference was observed due to type of chelator, presence of antioxidant, or surfactant. In order to optimize a biotherapeutic formulation to achieve a target drug product shelf life with acceptable quality, each formulation component must be evaluated for its impact.     

Removal of cadmium from aqueous system by shelled Moringa oleifera Lam. seed powder

The present study explores the unexploited sorption properties of the plant Moringa oleifera Lam. for decontamination of Cd at laboratory scale. Sorption studies using standard practices were carried out in batch experiments as functions of biomass dosage, contact time, metal concentrations, particle size and pH. Percentage sorption in each case was computed on the basis of Cd estimation using a planar NaI (TI) detector coupled to a 4K MCA (Canberra Accuspec Card with PC-AT 386). The adsorption data accurately in a Freundlich isotherm. Sorption studies resulted in the standardization of optimum conditions for removal of Cd (85.10%) as follows: biomass dosage (4.0 g), metal concentration (25 microg/ml), contact time (40 min) and volume of the test solution (200 ml) at pH 6.5. Fourier transform infrared (FTIR) spectrometry highlighted amino acid-Cd interactions responsible for sorption phenomenon. The findings open up new avenues in the removal of toxic metals by shelled Moringa oleifera seeds (SMOS) from water bodies as low cost, domestic and environmentally friendly safe technology.     

Fluorescence correlation spectroscopy of finite-sized particles

A theory is presented to study fluorescence correlation spectroscopy for particles with size comparable to the beam waist of the observation volume. Analytical correlation curves are derived for some experimentally interesting particle geometries. It is found that the finiteness of the particle generally decreases the value of the correlation amplitude and increases the correlation time compared to a point particle model. Furthermore, not only the size but also the distribution of fluorophores affects the shape of the correlation function. This is experimentally demonstrated with surface and internally labeled fluorescent spheres. In addition, experiments are performed on fluorescent spheres of different radii to validate the model by comparing the results to theoretical predictions.     

An elasticity-curvature illusion decouples cutaneous and proprioceptive cues in active exploration of soft objects

Our sense of touch helps us encounter the richness of our natural world. Across a myriad of contexts and repetitions, we have learned to deploy certain exploratory movements in order to elicit perceptual cues that are salient and efficient. The task of identifying optimal exploration strategies and somatosensory cues that underlie our softness perception remains relevant and incomplete. Leveraging psychophysical evaluations combined with computational finite element modeling of skin contact mechanics, we investigate an illusion phenomenon in exploring softness; where small-compliant and large-stiff spheres are indiscriminable. By modulating contact interactions at the finger pad, we find this elasticity-curvature illusion is observable in passive touch, when the finger is constrained to be stationary and only cutaneous responses from mechanosensitive afferents are perceptible. However, these spheres become readily discriminable when explored volitionally with musculoskeletal proprioception available. We subsequently exploit this phenomenon to dissociate relative contributions from cutaneous and proprioceptive signals in encoding our percept of material softness. Our findings shed light on how we volitionally explore soft objects, i.e., by controlling surface contact force to optimally elicit and integrate proprioceptive inputs amidst indiscriminable cutaneous contact cues. Moreover, in passive touch, e.g., for touch-enabled displays grounded to the finger, we find those spheres are discriminable when rates of change in cutaneous contact are varied between the stimuli, to supplant proprioceptive feedback.     

Biosorption of Cr (VI) from aqueous solution by Rhizopus nigricans

The study was aimed to quantify the Cr sorption ability of powdered biomass of Rhizopus nigricans at the best operating conditions. The influence of solution pH, agitation, Cr (VI) concentration, biomass dosage, contact time, biomass particle size and temperature were studied. The optimum pH for biosorption of Cr (VI) was found to be 2.0. Higher adsorption percentage was noted at lower initial concentrations of Cr ions, while the adsorption capacity of the biomass increased with increasing concentration of ions. Optimum biomass dosage was observed as 0.5% (w/v). More than 75% of the ions were removed within 30 min of contact and maximum removal was obtained after 8 h. Biomass particles of smaller size (90 microm) gave maximum adsorption (99.2%) at 100 mg/l concentration. The adsorption capacity increased with increase in temperature and agitation speed and the optimum were determined as 45 degrees C at 120 rpm. Freundlich and Langmuir isotherms were used to evaluate the data and the regression constants were derived. The adsorption rate constant values (Kad) were calculated for different initial concentration of Cr ions and the sorption was found to be higher at lower concentration (100 mg/l) of metal ion.     

Sea surface microlayer and elemental composition in phaeo‐, chloro‐, and rhodophytes in winter and spring

Trace metal or rare earth element (REE) content of marine macroalgae are underexamined and there is a great need for further understanding since macroalgae are used for food and may also be bioindicators of environmental changes. This study, by using high resolution inductive coupled plasma spectrometer in a clean laboratory (class 1000), investigates the trace metal and REE concentrations and composition in the youngest tissue of various species within three algal classes in the Trondheimsfjord, Norway, comprising phaeo‐, chloro‐, and rhodophytes in winter (February) and Spring (May) 2013, with the main focus on phaeophytes. The macroalgae were found in a clear zonation pattern as a function of depth. A significant difference in element concentration and composition was found between the six phaeophyte species along with a significant difference between winter and spring tissue. A zonation depth trend in algal tissue element concentration was also found for the phaeophytes, where the algal species located in both extreme ends (upper vs. lower littoral zone) obtained a lower element concentration than the algae located in the middle part of the littoral zone. This trend seems to result from different algal contact with the metal‐rich sea surface microlayer. The chlorophytes had 5–27 times higher concentration of REE and lead (Pb) than the two other algal classes. Results indicate that the rhodo‐ and chlorophytes are better accumulators than the phaeophytes for several trace metals and REE.     

Assessment of exposure to intermediate frequency electric fields and contact currents from a plasma ball

While electric fields at intermediate frequencies are not widely utilized for industrial technologies, surprisingly, certain toys emit the highest electric fields found in our living environment. These toys, plasma balls, are devices that use high voltage to create ionized light discharges. In this study, we assessed exposure to electric fields and contact/induced current from a recreational plasma ball device. The electric field strength was measured as a function of distance from the device, and the contact/induced current was measured with a current clamp in different exposure situations with point or grasping contact. The characteristic spectra of the electric field and contact current were measured, and both the multiple frequency rule and weighting of the spectra were applied according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) 1998 and 2010 guidelines. The results indicate that the recommended reference levels for the general public are exceeded at distances <1.2 m, and that the contact currents in the hand may be twice higher than recommended by the general public guidelines.     

Mitochondrial genome recombination in the zone of contact between two hybridizing conifers

Variation in mitochondrial DNA was surveyed at four gene loci in and around the zone of contact between two naturally hybridizing conifers, black spruce (Picea mariana) and red spruce (P. rubens) in northeastern North America. Most of the mtDNA diversity of these species was found in populations next to or into the zone of contact, where some individuals bore rare mitotypes intermediate between the common mitotypes observed in the allopatric areas of each species. Sequence analysis and tests for mtDNA recombination point to this phenomenon, rather than to recurrent mutation, as the most tenable hypothesis for the origin of these rare mitotypes. From the 10 mitotypes observed, at least 4 would be the product of recombination between 4 of the 5 putative ancestral mitotypes. Tests for cytonuclear disequilibrium and geographical structure of the putative recombinant mitotypes suggest that mtDNA recombination is not frequent and relatively recent on the geological time scale. mtDNA recombination would have been promoted by transient heteroplasmy due to leakage of paternal mtDNA since the Holocene secondary contact between the two species.     

Activated carbon prepared from biomass as adsorbent: elimination of Ni(II) from aqueous solution.

Activated carbon (AC) prepared from waste Parthenium was used to eliminate Ni(lI) from aqueous solution by adsorption. Batch mode adsorption experiments are carried out, by varying contact time, metal ion concentration, carbon concentration, pH and desorption to assess kinetic and equilibrium parameters. They allowed initial adsorption coefficient, adsorption rate constant and maximum adsorption capacities to be computed. The adsorption data were modeled by using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity (Q0) calculated from the Langmuir isotherm was 54.35 mg Ni(II)/g of AC at initial pH of 5.0 and 20 degrees C, for the particle size 250-500 microm. Increase in pH from 2 to 10 increased percent removal of metal ion. The regeneration by HCl of Ni(II)-saturated carbon by HCl, allowed suggestion of an adsorption mechanism by ion-exchange between metal ion and H+ ions on the AC surfaces. Quantitative recovery of Ni(II) was possible with HCl.     

Cloning and Characterization of the Flavobacterium johnsoniae Gliding Motility Genes gldD and gldE

Cells of Flavobacterium johnsoniae move over surfaces by a process known as gliding motility. The mechanism of this form of motility is not known. Cells of F. johnsoniae propel latex spheres along their surfaces, which is thought to be a manifestation of the motility machinery. Three of the genes that are required for F. johnsoniae gliding motility, gldA, gldB, and ftsX, have recently been described. Tn4351 mutagenesis was used to identify another gene, gldD, that is needed for gliding. Tn4351-induced gldD mutants formed nonspreading colonies, and cells failed to glide. They also lacked the ability to propel latex spheres and were resistant to bacteriophages that infect wild-type cells. Introduction of wild-type gldD into the mutants restored motility, ability to propel latex spheres, and sensitivity to bacteriophage infection. gldD codes for a cytoplasmic membrane protein that does not exhibit strong sequence similarity to proteins of known function. gldE, which lies immediately upstream of gldD, encodes another cytoplasmic membrane protein that may be involved in gliding motility. Overexpression of gldE partially suppressed the motility defects of a gldB point mutant, suggesting that GldB and GldE may interact. GldE exhibits sequence similarity to Borrelia burgdorferi TlyC and Salmonella enterica serovar Typhimurium CorC.     

Both sulfate-reducing bacteria and Enterobacteriaceae take part in marine biocorrosion of carbon steel

AIMS: In order to evaluate the part played in biocorrosion by microbial groups other than sulfate-reducing bacteria (SRB), we characterized the phylogenetic diversity of a corrosive marine biofilm attached to a harbour pile structure as well as to carbon steel surfaces (coupons) immersed in seawater for increasing time periods (1 and 8 months). We thus experimentally checked corroding abilities of defined species mixtures. METHODS AND RESULTS: Microbial community analysis was performed using both traditional cultivation techniques and polymerase chain reaction cloning-sequencing of 16S rRNA genes. Community structure of biofilms developing with time on immersed coupons tended to reach after 8 months, a steady state similar to the one observed on a harbour pile structure. Phylogenetic affiliations of isolates and cloned 16S rRNA genes (rrs) indicated that native biofilms (developing after 1-month immersion) were mainly colonized by gamma-proteobacteria. Among these, Vibrio species were detected in majority with molecular methods while cultivation techniques revealed dominance of Enterobacteriaceae such as Citrobacter, Klebsiella and Proteus species. Conversely, in mature biofilms (8-month immersion and pile structure), SRB, and to a lesser extent, spirochaetes were dominant. CONCLUSIONS: Corroding activity detection assays confirmed that Enterobacteriaceae (members of the gamma-proteobacteria) were involved in biocorrosion of metallic material in marine conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: In marine biofilms, metal corrosion may be initiated by Enterobacteriaceae.     

Size changes associated with metal adsorption onto modified bone gelatin beads

Significant quantities of heavy metals will adsorb onto modified bone gelatin beads. As this adsorption occurs, the bead can undergo a substantial volume change. Research has shown that the equilibrium bead diameter was a function of the solution pH and the ion concentration in the solution. Here, we demonstrate that under certain conditions, the volume of the beads that absorbed the metal was only 35% of the bead volume when no metal was adsorbed. By taking advantages of these size changes, a fluidized-bed separator can be operated such that natural segregation of loaded beads occurs. This phenomenon may facilitate the design of continous separators for the recovery and concentration of heavy-metal-contaminated waters. These concepts are demonstrated using Cu(2+) adsorption onto such beads.     

Characterizations of critical processes in liquid-liquid phase separation of the elastomeric protein-water system: microscopic observations and light scattering measurements

Biological self-assembly process of tropoelastin in an extracellular space, viewed as a key step of the elastogenesis, can be mimicked by the temperature-dependent coacervation of the elastin-related polypeptide-water system. Early and late stages of the phase separation behavior of the bovine neck ligamental alpha-elastin-water system were examined respectively by the laser light scattering photometry and phase contrast microscopy. Changes in the hydrodynamic size of molecular assemblies and visible microcoacervate droplet size were traced as a function of the concentration of alpha-elastin and temperature. Near the critical point, alpha-elastin concentration of 0.11 mg/mL and temperature of 21.5 degrees C, the phase separation was initiated after fast increase of the hydrodynamic size of primary aggregates as scattering particles and followed by the appearance of larger microcoacervate droplets with a broad size distribution. Whereas in the off-critical region, slow decrease of the hydrodynamic size of primary particles induced phase separation with smaller droplets of a narrow size distribution. Observation of the phase separation processes in the alpha-elastin-water system with metal chlorides and hydrophobic synthetic model polypeptide-water system indicated that the fast and slow molecular assembly processes were based on the fundamental hydrophobic interactions and involvements of electrostatic interactions between charged amino acid residues, respectively.     

Bayesian penalized-likelihood reconstruction algorithm suppresses edge artifacts in PET reconstruction based on point-spread-function

PurposeThe Bayesian penalized-likelihood reconstruction algorithm (BPL), Q.Clear, uses relative difference penalty as a regularization function to control image noise and the degree of edge-preservation in PET images. The present study aimed to determine the effects of suppression on edge artifacts due to point-spread-function (PSF) correction using a Q.Clear.MethodsSpheres of a cylindrical phantom contained a background of 5.3 kBq/mL of [¹⁸F]FDG and sphere-to-background ratios (SBR) of 16, 8, 4 and 2. The background also contained water and spheres containing 21.2 kBq/mL of [¹⁸F]FDG as non-background. All data were acquired using a Discovery PET/CT 710 and were reconstructed using three-dimensional ordered-subset expectation maximization with time-of-flight (TOF) and PSF correction (3D-OSEM), and Q.Clear with TOF (BPL). We investigated β-values of 200–800 using BPL. The PET images were analyzed using visual assessment and profile curves, edge variability and contrast recovery coefficients were measured.ResultsThe 38- and 27-mm spheres were surrounded by higher radioactivity concentration when reconstructed with 3D-OSEM as opposed to BPL, which suppressed edge artifacts. Images of 10-mm spheres had sharper overshoot at high SBR and non-background when reconstructed with BPL. Although contrast recovery coefficients of 10-mm spheres in BPL decreased as a function of increasing β, higher penalty parameter decreased the overshoot.ConclusionsBPL is a feasible method for the suppression of edge artifacts of PSF correction, although this depends on SBR and sphere size. Overshoot associated with BPL caused overestimation in small spheres at high SBR. Higher penalty parameter in BPL can suppress overshoot more effectively.     

Antagonist-induced deadhesion of specifically adhered vesicles

By use of a model system consisting of giant vesicles adhering to flat substrates, we identified, both experimentally and theoretically, two new control mechanisms for antagonist-induced deadhesion. Adhesion is established by specific binding of surface-grafted E-selectin and vesicle-carrying oligosaccharide Lewis(X). Deadhesion is achieved by controlled titration of monoclonal antibodies against E-selectin. The first mechanism is characterized by a considerable retraction of the contact zone resulting in a loss of contact area between the vesicle and the substrate. Within the developed theoretical framework, the observed equilibrium state is understood as a balance between the spreading pressure of the vesicle and the antagonist-induced lateral pressure at the edge of the contact zone. In the second mechanism, the antibodies induce unbinding by penetrating the contact zone without significantly affecting its size. This process reveals the decomposition of the adhesion zone into microdomains of tight binding separated by strongly fluctuating sections of the membrane. Both experiment and theory show a sigmoidal decrease of the number of bound ligands as a function of the logarithm of antagonist concentration. The work presented herein also provides a new method for the determination of the receptor binding affinity of either the surface-embedded ligands or the competing antagonist molecules.     

Sediment–Water Surface Area Along Rivers: Water Column Versus Benthic

Aquatic ecosystems have two distinct zones: the water column and benthic zone. Although the benthic zone has received considerable attention, recent studies have found the water column capable of accounting for a majority of whole ecosystem processes in rivers. The relative role of these zones inevitably varies across a size continuum of rivers, from headwaters to large transcontinental systems. A fundamental question in aquatic science is where along this size continuum do ecosystem processes potentially shift from occurring largely in the benthic zone to largely in the water column? Sediment structures the physical template of the benthic and water column zones of rivers and the contact area between water and sediment mediates ecological, geochemical, and physical processes. High concentrations of suspended sediments are hypothesized to cause a shift from benthic to water column dominance in rivers. We developed an analytical model for the contact area between surface water and all sediment particles in benthic and water column volumes. The model was implemented with empirical data along the main stem of major US rivers. The ratio of water column to benthic sediment contact area scaled as a power function of watershed area. There was more sediment–water contact area in the water column than the benthic zone in rivers equal to or greater than 5th to 9th order depending on the river basin. This suggests material processing could be occurring largely in the water column in rivers greater than 5th order. However, dams and variation in discharge caused rivers to oscillate between water column and benthic dominance over time and space.     

Bacterial corrosion of iron in seawater in situ, and in aerobic and anaerobic model systems

Abstract A screening of twenty-two marine isolates was made to examine their effects on corrosion of carbon steel ASTM A619. In batch cultures, sixteen of the isolates gave a lower corrosion than the control. Aerobic and anaerobic biofilm populations were formed by immersing iron coupons in natural seawater under aerobic and anaerobic conditions. The effects of the biofilms depended on a balance between the presence of oxygen and the type of population. An anaerobic population attached to the surface increased the corrosion rate if immersed in a suspension of Vibrio sp. DW1. The vibrio population probably 'protected' the anaerobic population from oxygen and may have provided nutrients, thereby creating conditions that allowed production of corrosive metabolites close to the metal. In contrast, coupons without a biofilm showed a decrease in the corrosion when immersed in the same vibrio suspension. The protective effect of a dense suspension of bacteria found earlier [5,6] was tested in situ in seawater. Iron coupons were immersed in dialysis bags with a suspension of Vibrio sp. DW1. Coupons immersed in dialysis bags with DW1 showed a lower degree of corrosion than coupons immersed in bags with seawater.     

Avidin-biotin interactions at vesicle surfaces: adsorption and binding, cross-bridge formation, and lateral interactions.

Densely packed domains of membrane proteins are important structures in cellular processes that involve ligand-receptor binding, receptor-mediated adhesion, and macromolecule aggregation. We have used the biotin-avidin interaction at lipid vesicle surfaces to mimic these processes, including the influence of a surface grafted polymer, polyethyleneglycol (PEG). Single vesicles were manipulated by micropipette in solutions of fluorescently labeled avidin to measure the rate and give an estimate of the amount of avidin binding to a biotinylated vesicle as a function of surface biotin concentration and surface-grafted PEG as PEG-lipid. The rate of avidin adsorption was found to be four times less with 2 mol% PEG750 than for the unmodified surface, and 10 mol% PEG completely inhibited binding of avidin to biotin for a 2-min incubation. Using two micropipettes, an avidin-coated vesicle was presented to a biotinylated vesicle. In this vesicle-vesicle adhesion test, the accumulation of avidin in the contact zone was observed, again by using fluorescent avidin. More importantly, by controlling the vesicle membrane tension, this adhesion test provided a direct measure of the spreading pressure of the biotin-avidin-biotin cross-bridges confined in the contact zone. Assuming ideality, this spreading pressure gives the concentration of avidin cross-bridges in the contact zone. The rate of cross-bridge accumulation was consistent with the diffusion of the lipid-linked "receptors" into the contact zone. Once adherent, the membranes failed in tension before they could be peeled apart. PEG750 did not influence the mechanical equilibrium because it was not compressed in the contact zone, but it did perform an important function by eliminating all nonspecific adhesion. This vesicle-vesicle adhesion experiment, with a lower tension limit of 0.01 dyn/cm, now provides a new and useful method with which to measure the spreading pressures and therefore colligative properties of a range of membrane-bound macromolecules.