Smooth Beads Research Articles

Protein-polysaccharide based double network microbeads improves stability of Bifidobacterium infantis ATCC 15697 in a gastro-Intestinal tract model (TIM-1)

Microencapsulation of probiotics is a main technique employed to improve cell survival in gastrointestinal tract (GIT). The present study investigated the impact of utilizing proteins i.e. Whey Protein Isolates (WPI), Pea Protein Isolates (PPI) or (WPI + PPI) complex based microbeads as encapsulating agents on the encapsulation efficiency (EE), diameter, morphology along with the survival and viability of Bifidobacterium infantis ATCC 15697. Results revealed that WPI + PPI combination had the highest EE% of the probiotics up to 94.09 % and the smoothest surface with less visible holes. WPI based beads revealed lower EE% and smaller size than PPI based ones. In addition, WPI based beads showed rough surface with visible signs of cracks, while PPI beads showed dense surfaces with pores and depressions. In contrast, the combination of the two proteins resulted in compact and smooth beads with less visible pores/wrinkles. The survival in gastrointestinal tract (GIT) was observed through TNO in-vitro gastrointestinal model (TIM-1) and results illustrated that all microbeads shrank in gastric phase while swelled in intestinal phase. In addition, in-vitro survival rate of free cells was very low in gastric phase (18.2 %) and intestinal phase (27.5 %). The free cells lost their viability after 28 days of storage (2.66 CFU/mL) with a maximum log reduction of 6.76, while all the encapsulated probiotic showed more than 106-7 log CFU/g viable cell. It was concluded that encapsulation improved the viability of probiotics in GIT and utilization of WPI + PPI in combination provided better protection to probiotics.

Influence of welding conditions and flux composition on chemistry of welds using recycled steel slag in submerged arc welding

The slag generated by steel-making plant has been employed to manufacture flux essential for submerged arc welding process. The developed flux has been used for depositing beads on plates, and the weld metal chemistry has been evaluated. The effect of welding conditions and flux composition on element transfer behavior has been investigated. The experiments were carried out as dictated by the design matrix generated using CCRD in response surface methodology. The data generated during experimentation was used to develop mathematical models. The developed models were tested for their adequacy through the ANOVA technique in design expert software. It is interesting to note that the recycled slag provided the chemistry of weld metal which is accepted as per ASME specifications. The rise in welding current increases the amount of carbon in weld metal from 0.11 to 0.14 wt.%, whereas it decreases with increasing travel speed. Manganese content decreases (1.28 wt.% to 0.795 wt.%) with increasing welding current (250 A to 650 A). The increase in welding speed from 4.44 mm/s to 8.88 mm/s results in an increment in manganese content from 0.87 wt.% to 1.21 wt.%. Since increasing travel speed decreases heat input per unit length of the weld, evaporation of manganese is suppressed. Therefore, the highest manganese content was achieved at a lower current (250 A) and higher speed (8.88 mm/s). Smooth beads with evenly distributed ripples free from surface defects like undercuts, porosity, pockmarks, etc., were achieved.

Optimization of Calcium Alginate Hydrogel Bioencapsulation of Acinetobacter junii B6, a Lipopeptide Biosurfactant Producer

Background: Biosurfactants are derived from microbes, plants, and animals. Acinetobacter junii B6 is a lipopeptide biosurfactant producer previously investigated for its structure, physicochemical, and product aggregation properties. Objectives: In this study, we investigated and optimized the bioencapsulation of A. junii B6 in calcium alginate hydrogel. Methods: Acinetobacter junii B6 was encapsulated using calcium alginate hydrogel. The formulation of the hydrogel was optimized using a full factorial approach. Sodium alginate concentration, calcium chloride concentration, and hardening time were selected as the main factors, and surface tension was the response measure. A scanning electron microscope (SEM) was used to study the bead's morphology. Results: Scanning electron microscope image showed rounded and smooth beads. The most biosurfactant production and reduced surface tension (35.98 mN/m) were observed at concentrations of 1% calcium chloride, (1%) sodium alginate, and 15 minutes of hardening time. Acinetobacter junii B6 can be encapsulated in alginate hydrogels producing biosurfactant at optimum experimental design. Conclusions: This represents a practical method for optimizing the bioencapsulation of A. junii B6 to produce biosurfactants.

Effect of pectic oligosaccharide on probiotic survival and physicochemical properties of hydrogel beads for synbiotic encapsulation of Lactobacillus bulgaricus

The present study was carried out to evaluate the effects of different concentrations of pectic oligosaccharide (POS) on the physicochemical properties of Lactobacillus bulgaricus (L. bulgaricus) loaded-synbiotic hydrogel beads and the survival of L. bulgaricus. Low methoxyl (LM) pectin-resistant starch (RS) hydrogel beads, named RS beads, were coated/filled with different concentrations of POS: 0.8% (RS-POS0.8 beads), 1.0% (RS-POS1.0 beads), and 1.2% (RS-POS1.2 beads). POS treatment resulted in smooth beads with less surface dent by hydrogen bonding between RS beads and POS, which was confirmed by SEM and XRD analyses. The encapsulation efficiency of RS beads and RS-POS beads ranged from 90.40% to 92.03%. In simulated gastric fluid (SGF) and bile salt solution, free L. bulgaricus completely died but L. bulgaricus encapsulated in RS-POS1.2 beads only slightly decreased. This indicates that RS-POS1.2 beads exhibited higher protective effects on L. bulgaricus under SGF condition and bile salts. Furthermore, considering the relatively higher storage stability of L. bulgaricus loaded in RS-POS1.2 beads, the present results suggest that RS beads coated/filled with POS could be used for synbiotic encapsulation, protection, and delivery of probiotics.

Temporal Decoration of the Female Head Gear of Upper Volga Region of 13th-15th Centuries

The author examines temporal decoration of the female head gear, revealed in the burial sites and on the settlements of the Upper Volga region of the 13th – 15th centuries. Throughout the 13th century the cast "imitation" jewelry was used, imitating pre-Mongolian precious attire with colts and temporal rings with grain and filigree beads. The most common decorations were the temporal rings with smooth beads, preserved in the attire until the end of the 14th century, and simple temporal rings of small and medium-diameter with entering ends and bent ends. The cast lunar false-woven rings were also revealed. In the 13th century the new forms of jewelry appeared. These are the temporal rings with a shaped blade, modifications of which used during the 13th –1th centuries. Probably the temporal rings were used in a combination with a rigid headgear and earrings, which became a part of the costume in the 14th century.

Design of Polyhydroxyalkanoate (PHA) Microbeads with Tunable Functional Properties and High Biodegradability in Seawater

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) were used to prepare microbeads, with diameter ranging from 50 to 100 µm, by an emulsion-evaporation process. The emulsification-evaporation process enables the formation of spherical polyhydroxyalcanoate beads, with crystalline rates similar to the ones of the former polymer and with important surface roughness as compared to amorphous polylactic acid smooth beads. The mechanical properties of the different PHA beads are also found to be intimately linked with their crystalline content, with modulus varying between 1 and 7 GPa. The degradation behavior of these PHA microbeads was tested under marine environment and revealed a rapid degradation, similar to cellulose, and a degradation rate correlated with the crystalline content. These results emphasize the possibility and interest in developing PHA materials with tunable functions and degradation properties.

CFD modelling of the effect of capillary pressure on retention behaviour of water menisci at inter-particle contacts

This paper presents a Computational Fluid Dynamics (CFD) model on the effect of capillary pressure on the retention behaviour of a granular material. The model proposes an unprecedented CFD insight into the onset of liquid menisci at the inter-particles contact under varying hydraulic conditions. The present work models the material grains as smooth spherical particles that define a porous network filled by two interstitial fluids: air and silicon oil. The numerical model has been subsequently validated against experimental measurements of the degree of saturation at different capillary pressures taken by Dullien et al. [F.A. Dullien, C. Zarcone, I.F. MacDonald, A. Collins, R.D. Bochard. J. Colloid Interface Sci. 127, 2 (1989)] in a system of smooth glass beads flooded with silicon oil. Results from the numerical simulations confirm the good capability of the model to reproduce the experimental retention behaviour of the granular material. Finally, the present paper laid the basis for future CFD studies on the effect of various factors (e.g. hydraulic hysteresis, surface roughness and/or grain shape) on the capillary pressure acting at the interparticle contact.

Co-Immobilization of Glucose Oxidase-Catalase: Optimization of Immobilization Parameters to Improve the Immobilization Yield

Co-immobilization of glucose oxidase (EC 1.1.3.4) and catalase (EC 1. 11.1.6) on non-porus glass surfaces using ?-aminopropyltriethoxysilane and polyethyleneimine as an activator and gluteraldehyde as cross linking agent has been carried out for its potential use. Polyethyleneimine was found to be a superior immobilization activator than ?-aminopropyltriethoxysilane. In present study, the effects of rough and smooth beads and optimization of the ratio of enzyme concentrations, activator material and concentration of the cross linking agent were investigated using response surface technology. With optimized concentration of glucose oxidase to catalase ratio (0.97), polyethyleneimine (150 mg/l) and gluteraldehyde (15 ml), the effect of glass bead concentration for maximum immobilization yield was investigated. Central composite optimization strategy with 16 experiments increased immobilization yield from 82.63% to 92.74%. It was observed that 0.3 ml of beads per 120 U of glucose oxidase were necessary for higher immobilization yield.

Surface roughness effects in granular matter: Influence on angle of repose and the absence of segregation

We investigate the effect of nanoscale variations in the surface roughness of individual particles on macroscale granular flow characteristics. Experiments were conducted in circular rotating tumblers with smooth and rough 2 and 3 mm steel particles. The smooth beads had a rms surface roughness of approximately 30 to 60 nm; rough beads had a surface roughness of approximately 240 to 350 nm. The dynamic angle of repose for rough particles increased by 10 degrees to 25 degrees over that of smooth particles over a wide range of rotation speeds. Even though surface roughness affects the angle of repose, we were unable to detect any segregation of bidisperse mixtures of rough and smooth particles in the radial direction in two-dimensional (2D) tumblers. Furthermore, no axial banding segregation occurred in 3D tumblers, both cylindrical and spherical. For mixtures of smooth and rough particles, the angle of repose increased monotonically with increasing concentration of rough particles. Particle dynamics simulations verified that the dependence of the angle of repose on the concentration of rough particles can be directly related to the coefficient of friction of the particles. Simulations over a broad range of friction parameters failed to induce segregation solely from differences in the angle of repose. These results indicate that nanoscale surface roughness can affect the flowability and angle of repose of granular matter without driving demixing of the bulk granular material.

How to use an abacus to help your child to count

A good abacus is a pleasure to touch. It should have wooden rods with rows of smooth wooden beads of different colours. Depending on size, there could be five or ten rows, with a ten-row abacus often using the colours of the five-row twice.

Effect of molecular scale roughness of glass beads on colloidal and bacterial deposition.

Molecular-scale surface roughness and charge heterogeneity have been hypothesized as factors that can affect the deposition rates of colloids during their transport in porous media. To test their relative importance, a single batch of cleaned glass beads was divided in half and chemically treated with acid or base to alter surface roughness. Analysis of the topography of 20 glass beads with an atomic force microscope (AFM) indicated that the chromic acid-treated (rough) beads had a root-mean-square roughness of 38.1 +/- 3.9 nm, while the sodium hydroxide-treated (smooth) beads had root-mean-square surface roughness of 15.0 +/- 1.9 nm. AFM force volume imaging of glass bead surfaces did not reveal surface charge heterogeneity. Filtration experiments with inorganic colloids (latex microspheres, 1 microm diameter) consistently demonstrated that there was a greater retention of latex microspheres on rough than smooth glass beads suspended in either low (10(-5) M) or higher (10(-1) M) ionic strength (IS) solutions. Collision efficiencies for rough beads were 30-50% larger than for smooth beads. Collision efficiencies of bacteria using rough glass beads were also equal to or greater than those measured for smooth beads. In experiments with the perchlorate-reducing bacterial isolate KJ, collision efficiencies were significantly greater on rough rather than smooth beads for two different ionic strength solutions (IS = 0.05 or 1 M). In another case (IS = 0.1 M) for KJ, and in filtration experiments with E coli, collision efficiencies were not significantly different between the rough and smooth beads. We hypothesize that the consistently greater deposition rates of microspheres, but not bacteria, on rough rather than smooth beads are due in part to the presence of polymers on the surfaces of bacteria.

Ice crystal patterns in artificial gels of extracellular matrix macromolecules after quick-freezing and freeze—Substitution

Artificial gels, composed of collagen with or without hyaluronate (HA), a glycosaminoglycan (GAG), and chondroitin sulfate (CS), were prepared and quick-frozen for the purpose of studying the influence of composition and concentration on ice patterns. Dilute gels were spread on coverslips, plunged into a slush of 30% isopentane/70% propane (−185 °C), freeze-substituted, and examined by phase-contrast microscopy. Ice patterns were revealed as “ice cavitites” in the gel after freeze-substitution. Ice morphology in the gels was gel-type-specific, suggesting that composition in dilute gels can influence ice pattern formation. Crystallization patterns reflecting high, intermediate, and low rates of freezing were observed in all gel types. Intermediate freezing velocities proved the most useful in differentiating gel-type-specific ice patterns. Gels which included hyaluronate (HA) and chondroitin sulfate (CS) altered the ice crystal pattern commonly observed in collagen gels. Ice structure in collagen gels consisted predominantly of long, parallel crystals in the herringbone pattern. Ice crystals separated gel into thin, unbranched fibers with a primary spacing of approximately 2 μm. Ice morphology in HA gels formed a mosaic consisting of packets of ice crystals. Contiguous packets were often oriented at right angles to each other. Periodic crossbridges interconnect primary gel fibers of HA gels and interrupt the lengthwise growth of ice crystals. Smooth beads were visible on primary strands in HA gels frozen at intermediate velocities. The addition of CS to collagen gels resulted in formation of randomly oriented ice crystals in gels frozen at intermediate rates. CS has little influence on ice morphology at low freezing velocities. Primary strands in CS gels were decorated with rough-surfaced, osmiophilic aggregates. Spacings between primary gel strands were not noticeably different (2 μm or less) in HA, CS, and standard gels. Ice crystals produced at intermediate freezing rates in extremely dilute gels form patterns that contribute to our understanding of the interaction of matrix constituents during the quick-freezing process.

The effects of surface roughness on the capillary pressure curves and the heights of capillary rise in glass bead packs

In this paper drainage and imbibition capillary pressure curves, obtained with various low viscosity oils by porous diaphragm tensiometry in packs of smooth and etched glass bead packs, are compared. Only in packs of smooth beads was there a definite irreducible wetting fluid saturation, whereas in packs of etched beads the wetting fluid saturation kept decreasing, without any apparent limit, with increasing applied capillary pressure. Residual wetting fluid saturations as low as 1% of the void space have been reached. Imbibition and drainage experiments have also been carried out in columns of both smooth and etched bead packs using molten paraffin wax. In the latter, the equilibrium heights were the same in drainage and in imbibition. The wetting liquid occupying the grooves in the surface of etched beads, which is responsible for these phenomena, was visualized by scanning electron microscopy and optical microscopy on samples in which styrene monomer was used in the drainage test and was subsequently polymerized.