Droplet-Free Digital Enzyme-Linked Immunosorbent Assay Based on a Tyramide Signal Amplification System.

PubMed

Akama, Kenji; Shirai, Kentaro; Suzuki, Seigo

2016-07-19

Digital enzyme-linked immunosorbent assay (ELISA) is a single molecule counting technology and is one of the most sensitive immunoassay methods. The key aspect of this technology is to concentrate enzyme reaction products from a single target molecule in femtoliter droplets. This study presents a novel Digital ELISA that does not require droplets; instead, enzyme reaction products are concentrated using a tyramide signal amplification system. In our method, tyramide substrate reacts with horseradish peroxidase (HRP) labeled with an immunocomplex on beads, and the substrate is converted into short-lived radical intermediates. By adjusting the bead concentration in the HRP-tyramide reaction and conducting the reaction using freely moving beads, tyramide radicals are deposited only on beads labeled with HRP and there is no diffusion to other beads. Consequently, the fluorescence signal is localized on a portion of the beads, making it possible to count the number of labeled beads digitally. The performance of our method was demonstrated by detecting hepatitis B surface antigen with a limit of detection of 0.09 mIU/mL (139 aM) and a dynamic range of over 4 orders of magnitude. The obtained limit of detection represents a >20-fold higher sensitivity than conventional ELISA. Our method has potential applications in simple in vitro diagnostic systems for detecting ultralow concentrations of protein biomarkers.

Self-organizing magnetic beads for biomedical applications

NASA Astrophysics Data System (ADS)

Gusenbauer, Markus; Kovacs, Alexander; Reichel, Franz; Exl, Lukas; Bance, Simon; Özelt, Harald; Schrefl, Thomas

2012-03-01

In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts functionalized with antibodies for circulating tumor cells. Creating these microposts with interacting magnetic beads makes it possible to tune the geometry in size, position and shape. We developed a simulation tool that combines micromagnetics and discrete particle dynamics, in order to design micropost arrays made of interacting beads. The simulation takes into account the viscous drag of the blood flow, magnetostatic interactions between the magnetic beads and gradient forces from external aligned magnets. We developed a particle-particle particle-mesh method for effective computation of the magnetic force and torque acting on the particles.

Do Clark's nutcrackers demonstrate what-where-when memory on a cache-recovery task?

PubMed

Gould, Kristy L; Ort, Amy J; Kamil, Alan C

2012-01-01

What-where-when (WWW) memory during cache recovery was investigated in six Clark's nutcrackers. During caching, both red- and blue-colored pine seeds were cached by the birds in holes filled with sand. Either a short (3 day) retention interval (RI) or a long (9 day) RI was followed by a recovery session during which caches were replaced with either a single seed or wooden bead depending upon the color of the cache and length of the retention interval. Knowledge of what was in the cache (seed or bead), where it was located, and when the cache had been made (3 or 9 days ago) were the three WWW memory components under investigation. Birds recovered items (bead or seed) at above chance levels, demonstrating accurate spatial memory. They also recovered seeds more than beads after the long RI, but not after the short RI, when they recovered seeds and beads equally often. The differential recovery after the long RI demonstrates that nutcrackers may have the capacity for WWW memory during this task, but it is not clear why it was influenced by RI duration.

Compatibility of epirubicin-loaded DC bead™ with different non-ionic contrast media.

PubMed

Sarakbi, Iman; Krämer, Irene

2016-12-01

The aim of this study was to determine the compatibility of epirubicin-loaded DC bead™ with different non-ionic contrast media over a period of seven days when stored light protected under refrigerated conditions. DC bead™ (2 ml) (Biocompatibles UK Ltd) of the bead size 70-150 µm ( = DC bead M1) or bead size 100-300 µm were loaded with 75 mg epirubicin powder formulation (Farmorubicin® dissolved in 3 ml water for injection to a concentration of 25 mg/ml) or 76 mg epirubicin injection solution (Epimedac® 2 mg/ml) within 2 h or 6 h, respectively. After removal of the excess solution, the epirubicin-loaded beads were mixed in polypropylene syringes with an equal volume (∼1.5 ml) of contrast media, i.e. Accupaque™ 300 (Nycomed Inc.), Imeron® 300 (Bracco S.p.A), Ultravist® 300 (Bayer Pharma AG), Visipaque™ 320 (GE Healthcare) and agitated in a controlled manner to get a homogenous suspension. Syringes with loaded beads in contrast media were stored protected from light under refrigeration (2-8℃). Compatibility was determined by measuring epirubicin concentrations in the suspensions in triplicate on day 0, 1, and 7. A reversed phase high-performance liquid chromatography assay with ultraviolet detection was utilized to analyze the concentration and purity of epirubicin. Mixing of epirubicin-loaded beads with different non-ionic contrast media released 0.1-0.5% of epirubicin over a period of 24 h, irrespectively, of the DC bead™ size or type of contrast media. No further elution or degradation was observed after seven days when the admixtures were stored protected from light under refrigeration. Compatibility of epirubicin-loaded DC bead™ with an equal volume of different contrast media in polypropylene syringes is given over a period of seven days. Due to a maximum elution of 0.1-0.5% of epirubicin from loaded DC bead™, admixtures with contrast media can be prepared in advance in centralized cytotoxic preparation units. Microbiological aspects have to be considered when determining the expiration date of the product. © The Author(s) 2015.

Bead mediated separation of microparticles in droplets.

PubMed

Wang, Sida; Sung, Ki-Joo; Lin, Xiaoxia Nina; Burns, Mark A

2017-01-01

Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead's solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield.

Westinghouse Modular Grinding Process - Enhancement of Volume Reduction for Hot Resin Supercompaction - 13491

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fehrmann, Henning; Aign, Joerg

2013-07-01

In nuclear power plants (NPP) ion exchange (IX) resins are used in several systems for water treatment. Spent resins can contain a significant amount of contaminates which makes treatment for disposal of spent resins mandatory. Several treatment processes are available such as direct immobilization with technologies like cementation, bitumisation, polymer solidification or usage of a high integrity container (HIC). These technologies usually come with a significant increase in final waste volume. The Hot Resin Supercompaction (HRSC) is a thermal treatment process which reduces the resin waste volume significantly. For a mixture of powdered and bead resins the HRSC process hasmore » demonstrated a volume reduction of up to 75 % [1]. For bead resins only the HRSC process is challenging because the bead resins compaction properties are unfavorable. The bead resin material does not form a solid block after compaction and shows a high spring back effect. The volume reduction of bead resins is not as good as for the mixture described in [1]. The compaction properties of bead resin waste can be significantly improved by grinding the beads to powder. The grinding also eliminates the need for a powder additive.Westinghouse has developed a modular grinding process to grind the bead resin to powder. The developed process requires no circulation of resins and enables a selective adjustment of particle size and distribution to achieve optimal results in the HRSC or in any other following process. A special grinding tool setup is use to minimize maintenance and radiation exposure to personnel. (authors)« less

Understanding the Impact of Bead Type on Paint and Thermoplastic Pavement Markings

DTIC Science & Technology

2012-03-01

20 Figure 7: Bead Performance Over Time for Polyurea (Needham, 2011) ......................... 23 Figure 8...specifically. Research conducted at the Air Force Institute of Technology reveals that bead type does impact the degradation rate of polyurea ...Preformed tape - profiled < 1.0 8 Methyl methacrylate < 1.0 9 Thermoplastics profiled < 1.0 10 Polyurea < 1.0 11 Cold applied plastics < 1.0 12

An Integrated Microfluidic Processor for DNA-Encoded Combinatorial Library Functional Screening

PubMed Central

2017-01-01

DNA-encoded synthesis is rekindling interest in combinatorial compound libraries for drug discovery and in technology for automated and quantitative library screening. Here, we disclose a microfluidic circuit that enables functional screens of DNA-encoded compound beads. The device carries out library bead distribution into picoliter-scale assay reagent droplets, photochemical cleavage of compound from the bead, assay incubation, laser-induced fluorescence-based assay detection, and fluorescence-activated droplet sorting to isolate hits. DNA-encoded compound beads (10-μm diameter) displaying a photocleavable positive control inhibitor pepstatin A were mixed (1920 beads, 729 encoding sequences) with negative control beads (58 000 beads, 1728 encoding sequences) and screened for cathepsin D inhibition using a biochemical enzyme activity assay. The circuit sorted 1518 hit droplets for collection following 18 min incubation over a 240 min analysis. Visual inspection of a subset of droplets (1188 droplets) yielded a 24% false discovery rate (1166 pepstatin A beads; 366 negative control beads). Using template barcoding strategies, it was possible to count hit collection beads (1863) using next-generation sequencing data. Bead-specific barcodes enabled replicate counting, and the false discovery rate was reduced to 2.6% by only considering hit-encoding sequences that were observed on >2 beads. This work represents a complete distributable small molecule discovery platform, from microfluidic miniaturized automation to ultrahigh-throughput hit deconvolution by sequencing. PMID:28199790

An Integrated Microfluidic Processor for DNA-Encoded Combinatorial Library Functional Screening.

PubMed

MacConnell, Andrew B; Price, Alexander K; Paegel, Brian M

2017-03-13

DNA-encoded synthesis is rekindling interest in combinatorial compound libraries for drug discovery and in technology for automated and quantitative library screening. Here, we disclose a microfluidic circuit that enables functional screens of DNA-encoded compound beads. The device carries out library bead distribution into picoliter-scale assay reagent droplets, photochemical cleavage of compound from the bead, assay incubation, laser-induced fluorescence-based assay detection, and fluorescence-activated droplet sorting to isolate hits. DNA-encoded compound beads (10-μm diameter) displaying a photocleavable positive control inhibitor pepstatin A were mixed (1920 beads, 729 encoding sequences) with negative control beads (58 000 beads, 1728 encoding sequences) and screened for cathepsin D inhibition using a biochemical enzyme activity assay. The circuit sorted 1518 hit droplets for collection following 18 min incubation over a 240 min analysis. Visual inspection of a subset of droplets (1188 droplets) yielded a 24% false discovery rate (1166 pepstatin A beads; 366 negative control beads). Using template barcoding strategies, it was possible to count hit collection beads (1863) using next-generation sequencing data. Bead-specific barcodes enabled replicate counting, and the false discovery rate was reduced to 2.6% by only considering hit-encoding sequences that were observed on >2 beads. This work represents a complete distributable small molecule discovery platform, from microfluidic miniaturized automation to ultrahigh-throughput hit deconvolution by sequencing.

NIST/ISAC standardization study: variability in assignment of intensity values to fluorescence standard beads and in cross calibration of standard beads to hard dyed beads.

PubMed

Hoffman, Robert A; Wang, Lili; Bigos, Martin; Nolan, John P

2012-09-01

Results from a standardization study cosponsored by the International Society for Advancement of Cytometry (ISAC) and the US National Institute of Standards and Technology (NIST) are reported. The study evaluated the variability of assigning intensity values to fluorophore standard beads by bead manufacturers and the variability of cross calibrating the standard beads to stained polymer beads (hard-dyed beads) using different flow cytometers. Hard dyed beads are generally not spectrally matched to the fluorophores used to stain cells, and spectral response varies among flow cytometers. Thus if hard dyed beads are used as fluorescence calibrators, one expects calibration for specific fluorophores (e.g., FITC or PE) to vary among different instruments. Using standard beads surface-stained with specific fluorophores (FITC, PE, APC, and Pacific Blue™), the study compared the measured intensity of fluorophore standard beads to that of hard dyed beads through cross calibration on 133 different flow cytometers. Using robust CV as a measure of variability, the variation of cross calibrated values was typically 20% or more for a particular hard dyed bead in a specific detection channel. The variation across different instrument models was often greater than the variation within a particular instrument model. As a separate part of the study, NIST and four bead manufacturers used a NIST supplied protocol and calibrated fluorophore solution standards to assign intensity values to the fluorophore beads. Values assigned to the reference beads by different groups varied by orders of magnitude in most cases, reflecting differences in instrumentation used to perform the calibration. The study concluded that the use of any spectrally unmatched hard dyed bead as a general fluorescence calibrator must be verified and characterized for every particular instrument model. Close interaction between bead manufacturers and NIST is recommended to have reliable and uniformly assigned fluorescence standard beads. Copyright © 2012 International Society for Advancement of Cytometry.

Bead mediated separation of microparticles in droplets

PubMed Central

Sung, Ki-Joo; Lin, Xiaoxia Nina; Burns, Mark A.

2017-01-01

Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead’s solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield. PMID:28282412

Accuracy of semen counting chambers as determined by the use of latex beads.

PubMed

Seaman, E K; Goluboff, E; BarChama, N; Fisch, H

1996-10-01

To assess the accuracy of the Hemacytometer (Hausser Scientific, Horsham, PA), Makler (Sefi-Medical Instrument, Haifa, Israel), Cell-VU (Millennium Sciences Inc., New York, NY), and Micro-Cell chambers (Conception Technologies, San Diego, CA) counting chambers. A solution containing a known concentration of latex beads was used as the standard to perform counts on the four different counting chambers. Bead counts for the four different chambers were compared with the bead counts of the standard solution. Variability within chambers also was determined. Mean bead concentrations for both the Cell-VU and Micro-Cell chambers were consistently similar to the bead concentration of the standard solution. Both the hemacytometer and the Makler chambers overestimated the actual bead concentration of the standard solution by as much as 50% and revealed significant interchamber variability. Our data revealed marked differences in the accuracy and reliability of the different counting chambers tested and emphasized the need for standardization and quality control of laboratory procedures.

Comparison of high pressure homogenization and stirred bead milling for the production of nano-crystalline suspensions.

PubMed

Nakach, Mostafa; Authelin, Jean-René; Perrin, Marc-Antoine; Lakkireddy, Harivardhan Reddy

2018-05-19

Currently, the two technologies primarily used for the manufacturing of nano-crystalline suspensions using top down process (i.e. wet milling) are high pressure homogenization (HPH) and stirred bead milling (SBM). These two technologies are based upon different mechanisms, i.e., cavitation forces for HPH and shear forces for stirred bead milling. In this article, the HPH and SBM technologies are compared in terms of the impact of the suspension composition the process parameters and the technological configuration on milling performances and physical quality of the suspensions produced. The data suggested that both HPH and SBM are suitable for producing nano-crystalline suspensions, although SBM appeared more efficient than HPH, since the limit of milling (d 50 ) for SBM was found to be lower than that obtained with HPH (100 nm vs 200 nm). For both these technologies, regardless of the process parameters used for milling and the scale of manufacturing, the relationship of d 90 versus d 50 could be described by a unique master curve (technology signature of milling pathway) outlining that the HPH leads to more uniform particle size distribution as compared to SBM. Copyright © 2018 Elsevier B.V. All rights reserved.

SaFaRI: sacral nerve stimulation versus the FENIX magnetic sphincter augmentation for adult faecal incontinence: a randomised investigation.

PubMed

Williams, Annabelle E; Croft, Julie; Napp, Vicky; Corrigan, Neil; Brown, Julia M; Hulme, Claire; Brown, Steven R; Lodge, Jen; Protheroe, David; Jayne, David G

2016-02-01

Faecal incontinence is a physically, psychologically and socially disabling condition. NICE guidance (2007) recommends surgical intervention, including sacral nerve stimulation (SNS), after failed conservative therapies. The FENIX magnetic sphincter augmentation (MSA) device is a novel continence device consisting of a flexible band of interlinked titanium beads with magnetic cores that is placed around the anal canal to augment anal sphincter tone through passive attraction of the beads. Preliminary studies suggest the FENIX MSA is safe, but efficacy data is limited. Rigorous evaluation is required prior to widespread adoption. The SaFaRI trial is a National Institute of Health Research (NIHR) Health Technology Assessment (HTA)-funded UK multi-site, parallel group, randomised controlled, unblinded trial that will investigate the use of the FENIX MSA, as compared to SNS, for adult faecal incontinence resistant to conservative management. Twenty sites across the UK, experienced in the treatment of faecal incontinence, will recruit 350 patients randomised equally to receive either SNS or FENIX MSA. Participants will be followed-up at 2 weeks post-surgery and at 6, 12 and 18 months post-randomisation. The primary endpoint is success, as defined by device in use and ≥50 % improvement in the Cleveland Clinic Incontinence Score (CCIS) at 18 months post-randomisation. Secondary endpoints include complications, quality of life and cost effectiveness. SaFaRI will rigorously evaluate a new technology for faecal incontinence, the FENIX™ MSA, allowing its safe and controlled introduction into current clinical practice. These results will inform the future surgical management of adult faecal incontinence.

The 4-parameter Compressible Packing Model (CPM) including a critical cavity size ratio

NASA Astrophysics Data System (ADS)

Roquier, Gerard

2017-06-01

The 4-parameter Compressible Packing Model (CPM) has been developed to predict the packing density of mixtures constituted by bidisperse spherical particles. The four parameters are: the wall effect and the loosening effect coefficients, the compaction index and a critical cavity size ratio. The two geometrical interactions have been studied theoretically on the basis of a spherical cell centered on a secondary class bead. For the loosening effect, a critical cavity size ratio, below which a fine particle can be inserted into a small cavity created by touching coarser particles, is introduced. This is the only parameter which requires adaptation to extend the model to other types of particles. The 4-parameter CPM demonstrates its efficiency on frictionless glass beads (300 values), spherical particles numerically simulated (20 values), round natural particles (125 values) and crushed particles (335 values) with correlation coefficients equal to respectively 99.0%, 98.7%, 97.8%, 96.4% and mean deviations equal to respectively 0.007, 0.006, 0.007, 0.010.

New, hybrid pectin-based biosorbents

PubMed Central

Jakóbik-Kolon, Agata; Milewski, Andrzej K.; Karoń, Krzysztof; Bok-Badura, Joanna

2016-01-01

ABSTRACT In this work hybrid pectin-based biosorbents with secondary polysaccharide additives (gellan, carob and xanthan gum, ratio to pectin 1:1, 1:1 and 1:3, respectively) were obtained at two temperatures. The presence of these additives in prepared beads was confirmed by Raman spectra. The SEM micrographs show better homogeneity of blends and grater differences between structures of beads with various additives obtained at higher temperature. The sorption capacity of our hybrid biosorbents as well as sole pectin sorbent is rather the same, and equals 0.85 and 0.70 mmol/g for lead and cadmium, respectively, in pH 4–6. PMID:27812233

Growth and morphology of thermophilic dairy starters in alginate beads.

PubMed

Lamboley, Laurence; St-Gelais, Daniel; Champagne, Claude P; Lamoureux, Maryse

2003-06-01

The aim of this research was to produce concentrated biomasses of thermophilic lactic starters using immobilized cell technology (ICT). Fermentations were carried out in milk using pH control with cells microentrapped in alginate beads. In the ICT fermentations, beads represented 17% of the weight. Some assays were carried out with free cells without pH control, in order to compare the ICT populations with those of classical starters. With Streptococcus thermophilus, overall populations in the fermentor were similar, but maximum bead population for (8.2 x 10(9) cfu/g beads) was 13 times higher than that obtained in a traditional starter (4.9 x 10(8) cfu/ml). For both Lactobacillus helveticus strains studied, immobilized-cell populations were about 3 x 10(9) cfu/g beads. Production of immobilized Lb. bulgaricus 210R strain was not possible, since no increases in viable counts occurred in beads. Therefore, production of concentrated cell suspension in alginate beads was more effective for S. thermophilus. Photomicrographs of cells in alginate beads demonstrated that, while the morphology of S. thermophilus remained unchanged during the ICT fermentation, immobilized cells of Lb. helveticus appeared wider. In addition, cells of Lb. bulgaricus were curved and elongated. These morphological changes would also impair the growth of immobilized lactobacilli.

Negative dielectrophoresis spectroscopy for rare analyte quantification in biological samples

NASA Astrophysics Data System (ADS)

Kirmani, Syed Abdul Mannan; Gudagunti, Fleming Dackson; Velmanickam, Logeeshan; Nawarathna, Dharmakeerthi; Lima, Ivan T., Jr.

2017-03-01

We propose the use of negative dielectrophoresis (DEP) spectroscopy as a technique to improve the detection limit of rare analytes in biological samples. We observe a significant dependence of the negative DEP force on functionalized polystyrene beads at the edges of interdigitated electrodes with respect to the frequency of the electric field. We measured this velocity of repulsion for 0% and 0.8% conjugation of avidin with biotin functionalized polystyrene beads with our automated software through real-time image processing that monitors the Rayleigh scattering from the beads. A significant difference in the velocity of the beads was observed in the presence of as little as 80 molecules of avidin per biotin functionalized bead. This technology can be applied in the detection and quantification of rare analytes that can be useful in the diagnosis and the treatment of diseases, such as cancer and myocardial infarction, with the use of polystyrene beads functionalized with antibodies for the target biomarkers.

An integrated open-cavity system for magnetic bead manipulation.

PubMed

Abu-Nimeh, F T; Salem, F M

2013-02-01

Superparamagnetic beads are increasingly used in biomedical assays to manipulate, transport, and maneuver biomaterials. We present a low-cost integrated system designed in bulk CMOS to manipulate and separate biomedical magnetic beads. The system consists of 8 × 8 coil-arrays suitable for single bead manipulation, or collaborative multi-bead manipulation, using pseudo-parallel executions. We demonstrate the flexibility of the design in terms of different coil sizes, DC current levels, and layout techniques. In one array module example, the size of a single coil is 30 μm × 30 μm and the full array occupies an area of 248 μm × 248 μm in 0.5 μm CMOS technology. The programmable DC current source supports 8 discrete levels up to 1.5 mA. The total power consumption of the entire module is 9 mW when running at full power.

On-bead antibody-small molecule conjugation using high-capacity magnetic beads.

PubMed

Nath, Nidhi; Godat, Becky; Benink, Hélène; Urh, Marjeta

2015-11-01

Antibodies labeled with small molecules such as fluorophore, biotin or drugs play an important role in various areas of biological research, drug discovery and diagnostics. However, the majority of current methods for labeling antibodies is solution-based and has several limitations including the need for purified antibodies at high concentrations and multiple buffer exchange steps. In this study, a method (on-bead conjugation) is described that addresses these limitations by combining antibody purification and conjugation in a single workflow. This method uses high capacity-magnetic Protein A or Protein G beads to capture antibodies directly from cell media followed by conjugation with small molecules and elution of conjugated antibodies from the beads. High-capacity magnetic antibody capture beads are key to this method and were developed by combining porous and hydrophilic cellulose beads with oriented immobilization of Protein A and Protein G using HaloTag technology. With a variety of fluorophores it is shown that the on-bead conjugation method is compatible with both thiol- and amine-based chemistry. This method enables simple and rapid processing of multiple samples in parallel with high-efficiency antibody recovery. It is further shown that recovered antibodies are functional and compatible with downstream applications. Copyright © 2015. Published by Elsevier B.V.

Assessment of fluid distribution and flow properties in two phase fluid flow using X-ray CT technology

NASA Astrophysics Data System (ADS)

Jiang, Lanlan; Wu, Bohao; Li, Xingbo; Wang, Sijia; Wang, Dayong; Zhou, Xinhuan; Zhang, Yi

2018-04-01

To study on microscale distribution of CO2 and brine during two-phase flow is crucial for understanding the trapping mechanisms of CO2 storage. In this study, CO2-brine flow experiments in porous media were conducted using X-ray computed tomography. The porous media were packed with glass beads. The pore structure (porosity/tortuosity) and flow properties at different flow rates and flow fractions were investigated. The results showed that porosity of the packed beads differed at different position as a result of heterogeneity. The CO2 saturation is higher at low injection flow rates and high CO2 fractions. CO2 distribution at the pore scale was also visualized. ∅ Porosity of porous media CT brine_ sat grey value of sample saturated with brine CT dry grey value of sample saturated with air CT brine grey value of pure brine CT air grey value of pure air CT flow grey values of sample with two fluids occupying the pore space {CT}_{CO_2_ sat} grey value of sample saturated with CO2 {f}_{CO_2}({S}_{CO_2}) CO2 fraction {q}_{CO_2} the volume flow rate for CO2 q brine the volume flow rate for brine L Thickness of the porous media, mm L e a bundle of capillaries of equal length, mm τ Tortuosity, calculated from L e / L.

Hydrodynamic Torques and Rotations of Superparamagnetic Bead Dimers

NASA Astrophysics Data System (ADS)

Pease, Christopher; Etheridge, J.; Wijesinghe, H. S.; Pierce, C. J.; Prikockis, M. V.; Sooryakumar, R.

Chains of micro-magnetic particles are often rotated with external magnetic fields for many lab-on-a-chip technologies such as transporting beads or mixing fluids. These applications benefit from faster responses of the actuated particles. In a rotating magnetic field, the magnetization of superparamagnetic beads, created from embedded magnetic nano-particles within a polymer matrix, is largely characterized by induced dipoles mip along the direction of the field. In addition there is often a weak dipole mop that orients out-of-phase with the external rotating field. On a two-bead dimer, the simplest chain of beads, mop contributes a torque Γm in addition to the torque from mip. For dimers with beads unbound to each other, mop rotates individual beads which generate an additional hydrodynamic torque on the dimer. Whereas, mop directly torques bound dimers. Our results show that Γm significantly alters the average frequency-dependent dimer rotation rate for both bound and unbound monomers and, when mop exceeds a critical value, increases the maximum dimer rotation frequency. Models that include magnetic and hydrodynamics torques provide good agreement with the experimental findings over a range of field frequencies.

Peptide library synthesis on spectrally encoded beads for multiplexed protein/peptide bioassays

NASA Astrophysics Data System (ADS)

Nguyen, Huy Q.; Brower, Kara; Harink, Björn; Baxter, Brian; Thorn, Kurt S.; Fordyce, Polly M.

2017-02-01

Protein-peptide interactions are essential for cellular responses. Despite their importance, these interactions remain largely uncharacterized due to experimental challenges associated with their measurement. Current techniques (e.g. surface plasmon resonance, fluorescence polarization, and isothermal calorimetry) either require large amounts of purified material or direct fluorescent labeling, making high-throughput measurements laborious and expensive. In this report, we present a new technology for measuring antibody-peptide interactions in vitro that leverages spectrally encoded beads for biological multiplexing. Specific peptide sequences are synthesized directly on encoded beads with a 1:1 relationship between peptide sequence and embedded code, thereby making it possible to track many peptide sequences throughout the course of an experiment within a single small volume. We demonstrate the potential of these bead-bound peptide libraries by: (1) creating a set of 46 peptides composed of 3 commonly used epitope tags (myc, FLAG, and HA) and single amino-acid scanning mutants; (2) incubating with a mixture of fluorescently-labeled antimyc, anti-FLAG, and anti-HA antibodies; and (3) imaging these bead-bound libraries to simultaneously identify the embedded spectral code (and thus the sequence of the associated peptide) and quantify the amount of each antibody bound. To our knowledge, these data demonstrate the first customized peptide library synthesized directly on spectrally encoded beads. While the implementation of the technology provided here is a high-affinity antibody/protein interaction with a small code space, we believe this platform can be broadly applicable to any range of peptide screening applications, with the capability to multiplex into libraries of hundreds to thousands of peptides in a single assay.

Butt Welding Joint of Aluminum Alloy by Space GHTA Welding Process in Vacuum

NASA Astrophysics Data System (ADS)

Suita, Yoshikazu; Shinike, Shuhei; Ekuni, Tomohide; Terajima, Noboru; Tsukuda, Yoshiyuki; Imagawa, Kichiro

Aluminum alloys have been used widely in constructing various space structures including the International Space Station (ISS) and launch vehicles. For space applications, welding experiments on aluminum alloy were performed using the GHTA (Gas Hollow Tungsten Arc) welding process using a filler wire feeder in a vacuum. We investigated the melting phenomenon of the base metal and filler wire, bead formation, and the effects of wire feed speed on melting characteristics. The melting mechanism in the base metal during the bead on a plate with wire feed was similar to that for the melt run without wire feed. We clarified the effects of wire feed speed on bead sizes and configurations. Furthermore, the butt welded joint welded using the optimum wire feed speed, and the joint tensile strengths were evaluated. The tensile strength of the square butt joint welded by the pulsed DC GHTA welding with wire feed in a vacuum is nearly equal to that of the same joint welded by conventional GTA (Gas Tungsten Arc) welding in air.

A Phos-tag-based magnetic-bead method for rapid and selective separation of phosphorylated biomolecules.

PubMed

Tsunehiro, Masaya; Meki, Yuma; Matsuoka, Kanako; Kinoshita-Kikuta, Emiko; Kinoshita, Eiji; Koike, Tohru

2013-04-15

A simple and efficient method based on magnetic-bead technology has been developed for the separation of phosphorylated and nonphosphorylated low-molecular-weight biomolecules, such as nucleotides, phosphorylated amino acids, or phosphopeptides. The phosphate-binding site on the bead is an alkoxide-bridged dinuclear zinc(II) complex with 1,3-bis(pyridin-2-ylmethylamino)propan-2-olate (Phos-tag), which is linked to a hydrophilic cross-linked agarose coating on a magnetic core particle. All steps for the phosphate-affinity separation are conducted in buffers of neutral pH with 50 μL of the magnetic beads in a 1.5-mL microtube. The entire separation protocol for phosphomonoester-type compounds, from addition to elution, requires less than 12 min per sample if the buffers and the zinc(II)-bound Phos-tag magnetic beads have been prepared in advance. The phosphate-affinity magnetic beads are reusable at least 15 times without a decrease in their phosphate-binding ability and they are stable for three months in propan-2-ol. Copyright © 2013 Elsevier B.V. All rights reserved.

The Use of AlphaScreen Technology in HTS: Current Status

PubMed Central

Eglen, Richard M; Reisine, Terry; Roby, Philippe; Rouleau, Nathalie; Illy, Chantal; Bossé, Roger; Bielefeld, Martina

2008-01-01

AlphaScreen (Amplified Luminescent Proximity Homogeneous Assay Screen) is versatile assay technology developed to measuring analytes using a homogenous protocol. This technology is an example of a bead-based proximity assay and was developed from a diagnostic assay technology known as LOCI (Luminescent Oxygen Channeling Assay). Here, singlet oxygen molecules, generated by high energy irradiation of Donor beads, travel over a constrained distance (approx. 200 nm) to Acceptor beads. This results in excitation of a cascading series of chemical reactions, ultimately causing generation of a chemiluminescent signal. In the past decade, a wide variety of applications has been reported, ranging from detection of analytes involved in cell signaling, including protein:protein, protein:peptide, protein:small molecule or peptide:peptide interactions. Numerous homogeneous HTS-optimized assays have been reported using the approach, including generation of second messengers (such as accumulation of cyclic AMP, cyclic GMP, inositol [1, 4, 5] trisphosphate or phosphorylated ERK) from liganded GPCRs or tyrosine kinase receptors, post-translational modification of proteins (such as proteolytic cleavage, phosphorylation, ubiquination and sumoylation) as well as protein-protein and protein-nucleic acid interactions. Recently, the basic AlphaScreen technology was extended in that the chemistry of the Acceptor bead was modified such that emitted light is more intense and spectrally defined, thereby markedly reducing interference from biological fluid matrices (such as trace hemolysis in serum and plasma). In this format, referred to as AlphaLISA, it provides an alternative technology to classical ELISA assays and is suitable for high throughput automated fluid dispensing and detection systems. Collectively, AlphaScreen and AlphaLISA technologies provide a facile assay platform with which one can quantitate complex cellular processes using simple no-wash microtiter plate based assays. They provide the means by which large compound libraries can be screened in a high throughput fashion at a diverse range of therapeutically important targets, often not readily undertaken using other homogeneous assay technologies. This review assesses the current status of the technology in drug discovery, in general, and high throughput screening (HTS), in particular. PMID:20161822

Rapid Detection of Enterobacter Sakazakii in milk Powder using amino modified chitosan immunomagnetic beads.

PubMed

Zhu, Yinglian; Wang, Dongfeng

2016-12-01

Chitosan immunomagnetic beads (CIBs) were first prepared through converting hydroxyl groups of natural polymer material-chitosan into amino groups using epichlorohydrin and ethylenediamine as modification agent and then coupling with polyclonal antibodies of Enterobacter sakazakii using glutaraldehyde as cross-linking agent. The beads before coupling with antibodies were characterized by magnetic property measurement, FTIR, SEM and XRD technologies. In the assay a natural polysaccharide-chitosan, which has good biological and chemical properties such as non-toxicity, biocompatibility and high chemical reactivity was first used for synthesis of immunomagnetic beads. The detection method first established in this paper that combined the beads with chromogenic medium together to rapid detect E. sakazakii in milk powder could greatly improve the detection specificity and working efficiency. The beads exhibited a maximum capturing capacity of 1×10 6 cfu/g with the detection sensitivity of 4cfu/g. The results demonstrate that the assay is a straightforward, specific and sensitive alternative for rapid detection of E.sakazakii in food matrix. The total analysis time was as little as about 25h, which greatly shorten the detection time. The method can provides new ideas not only to preparation technique of immunomagnetic beads but to imunne detection technique in food safety. Copyright © 2016 Elsevier B.V. All rights reserved.

Flow cytometry for enrichment and titration in massively parallel DNA sequencing

PubMed Central

Sandberg, Julia; Ståhl, Patrik L.; Ahmadian, Afshin; Bjursell, Magnus K.; Lundeberg, Joakim

2009-01-01

Massively parallel DNA sequencing is revolutionizing genomics research throughout the life sciences. However, the reagent costs and labor requirements in current sequencing protocols are still substantial, although improvements are continuously being made. Here, we demonstrate an effective alternative to existing sample titration protocols for the Roche/454 system using Fluorescence Activated Cell Sorting (FACS) technology to determine the optimal DNA-to-bead ratio prior to large-scale sequencing. Our method, which eliminates the need for the costly pilot sequencing of samples during titration is capable of rapidly providing accurate DNA-to-bead ratios that are not biased by the quantification and sedimentation steps included in current protocols. Moreover, we demonstrate that FACS sorting can be readily used to highly enrich fractions of beads carrying template DNA, with near total elimination of empty beads and no downstream sacrifice of DNA sequencing quality. Automated enrichment by FACS is a simple approach to obtain pure samples for bead-based sequencing systems, and offers an efficient, low-cost alternative to current enrichment protocols. PMID:19304748

Bead-on-string structure printed by electrohydrodynamic jet under alternating current electric field

NASA Astrophysics Data System (ADS)

Liu, Juan; Lin, Yihuang; Jiang, Jiaxin; Liu, Haiyan; Zhao, Yang; Zheng, Gaofeng

2016-09-01

Electrohydrodynamic printing (EHDP) under alternating current (AC) electric field provides a novel way for the precise micro-/nano-droplet printing. The AC electric field induces the free charge to reciprocate along the EHDP jet and changes the electric field force on the jet periodically. The stability of jet can be enhanced by increasing the voltage frequency, and the regular bead-on-string structure is direct-written along the trajectory of collector. The deposition frequency of bead structure increases with the increasing of voltage frequency, due to the short period of AC electric field. As the voltage frequency is increased from 10 to 60 Hz, the diameter of bead structure decreases from 200 to 110 µm. As the duty ration increased from 10 to 60 %, the diameter of bead structure increased from 100 to 140 µm. This work would accelerate the development and the application of micro-/nano-printing technology in the fields of flexible electronic and micro-/nano-system.

Alginate Beads Containing Lactase: Stability and Microstructure.

PubMed

Traffano-Schiffo, Maria Victoria; Aguirre Calvo, Tatiana R; Castro-Giraldez, Marta; Fito, Pedro J; Santagapita, Patricio R

2017-06-12

β-Galactosidase (lactase) is a widely used enzyme in the food industry; however, it has low stability against thermal and mechanical treatments. Due to this, the purpose of the present research was to analyze the encapsulation of lactase in alginate-Ca(II) beads in order to maintain its enzymatic activity toward freezing, freezing/thawing, and storage. Also, the effect of the addition of trehalose, and arabic and guar gums and their influence on the microstructure as well as on thermal properties and molecular mobility were studied. Lactase was successfully encapsulated in alginate-Ca(II) beads, and the inclusion of trehalose was critical for activity preservation toward treatments, being improved in guar gum-containing systems. The gums increased the T m ' values, which represents a valuable technological improvement. Finally, the presence of secondary excipients affected the microstructure, showing rods with smaller outer diameter and with lower compactness than alginate-Ca(II) beads. Also, bead composition greatly affects the size, shape, and relaxation times.

Microelectrophoresis of a bilayer-coated silica bead in an optical trap: application to enzymology.

PubMed

Galneder, R; Kahl, V; Arbuzova, A; Rebecchi, M; Rädler, J O; McLaughlin, S

2001-05-01

We describe an apparatus that combines microelectrophoresis and laser trap technologies to monitor the activity of phosphoinositide-specific phospholipase C-delta1 (PLC-delta) on a single bilayer-coated silica bead with a time resolution of approximately 1 s. A 1-microm-diameter bead was coated with a phospholipid bilayer composed of electrically neutral phosphatidylcholine (PC) and negatively charged phosphatidylinositol 4,5-bisphosphate (2% PIP2) and captured in a laser trap. When an AC field was applied (160 Hz, 20 V/cm), the electrophoretic force produced a displacement of the bead, Delta(x), from its equilibrium position in the trap; Delta(x), which was measured using a fast quadrant diode detector, is proportional to the zeta potential and thus to the number of PIP2 molecules on the outer leaflet (initially, approximately 10(5)). When a solution containing PLC-delta flows past the bead, the enzyme adsorbs to the surface and hydrolyzes PIP2 to form the neutral lipid diacylglycerol. We observed a nonexponential decay of PIP2 on the bead with time that is consistent with a model based on the known structural properties of PLC-delta.

Perfect count: a novel approach for the single platform enumeration of absolute CD4+ T-lymphocytes.

PubMed

Storie, Ian; Sawle, Alex; Goodfellow, Karen; Whitby, Liam; Granger, Vivian; Ward, Rosalie Y; Peel, Janet; Smart, Theresa; Reilly, John T; Barnett, David

2004-01-01

The derivation of reliable CD4(+) T lymphocyte counts is vital for the monitoring of disease progression and therapeutic effectiveness in HIV(+) individuals. Flow cytometry has emerged as the method of choice for CD4(+) T lymphocyte enumeration, with single-platform technology, coupled with reference counting beads, fast becoming the "gold standard." However, although single-platform, bead-based, sample acquisition requires the ratio of beads to cells to remain unchanged, there is no available method, until recently, to monitor this. Perfect Count beads have been developed to address this issue and to incorporate two bead populations, with different densities, to allow the detection of inadequate mixing. Comparison of the relative proportions of both beads with the manufacture's defined limits enables an internal QC check during sample acquisition. In this study, we have compared CD4(+) T lymphocyte counts, obtained from 104 HIV(+) patients, using TruCount beads with MultiSet software (defined as the predicated method) and the new Perfect Count beads, incorporating an in house sequential gating strategy. We have demonstrated an excellent degree of correlation between the predicate method and the Perfect Count system (r(2) = 0.9955; Bland Altman bias +27 CD4(+) T lymphocytes/microl). The Perfect Count system is a robust method for performing single platform absolute counts and has the added advantage of having internal QC checks. Such an approach enables the operator to identify potential problems during sample preparation, acquisition and analysis. Copyright 2003 Wiley-Liss, Inc.

Experimental evidence of solitary wave interaction in Hertzian chains

NASA Astrophysics Data System (ADS)

Santibanez, Francisco; Munoz, Romina; Caussarieu, Aude; Job, Stéphane; Melo, Francisco

2011-08-01

We study experimentally the interaction between two solitary waves that approach one another in a linear chain of spheres interacting via the Hertz potential. When these counterpropagating waves collide, they cross each other and a phase shift in respect to the noninteracting waves is introduced as a result of the nonlinear interaction potential. This observation is well reproduced by our numerical simulations and is shown to be independent of viscoelastic dissipation at the bead contact. In addition, when the collision of equal amplitude and synchronized counterpropagating waves takes place, we observe that two secondary solitary waves emerge from the interacting region. The amplitude of the secondary solitary waves is proportional to the amplitude of incident waves. However, secondary solitary waves are stronger when the collision occurs at the middle contact in chains with an even number of beads. Although numerical simulations correctly predict the existence of these waves, experiments show that their respective amplitudes are significantly larger than predicted. We attribute this discrepancy to the rolling friction at the bead contact during solitary wave propagation.

A general method for bead-enhanced quantitation by flow cytometry

PubMed Central

Montes, Martin; Jaensson, Elin A.; Orozco, Aaron F.; Lewis, Dorothy E.; Corry, David B.

2009-01-01

Flow cytometry provides accurate relative cellular quantitation (percent abundance) of cells from diverse samples, but technical limitations of most flow cytometers preclude accurate absolute quantitation. Several quantitation standards are now commercially available which, when added to samples, permit absolute quantitation of CD4+ T cells. However, these reagents are limited by their cost, technical complexity, requirement for additional software and/or limited applicability. Moreover, few studies have validated the use of such reagents in complex biological samples, especially for quantitation of non-T cells. Here we show that addition to samples of known quantities of polystyrene fluorescence standardization beads permits accurate quantitation of CD4+ T cells from complex cell samples. This procedure, here termed single bead-enhanced cytofluorimetry (SBEC), was equally capable of enumerating eosinophils as well as subcellular fragments of apoptotic cells, moieties with very different optical and fluorescent characteristics. Relative to other proprietary products, SBEC is simple, inexpensive and requires no special software, suggesting that the method is suitable for the routine quantitation of most cells and other particles by flow cytometry. PMID:17067632

Design criteria for developing low-resource magnetic bead assays using surface tension valves

PubMed Central

Adams, Nicholas M.; Creecy, Amy E.; Majors, Catherine E.; Wariso, Bathsheba A.; Short, Philip A.; Wright, David W.; Haselton, Frederick R.

2013-01-01

Many assays for biological sample processing and diagnostics are not suitable for use in settings that lack laboratory resources. We have recently described a simple, self-contained format based on magnetic beads for extracting infectious disease biomarkers from complex biological samples, which significantly reduces the time, expertise, and infrastructure required. This self-contained format has the potential to facilitate the application of other laboratory-based sample processing assays in low-resource settings. The technology is enabled by immiscible fluid barriers, or surface tension valves, which stably separate adjacent processing solutions within millimeter-diameter tubing and simultaneously permit the transit of magnetic beads across the interfaces. In this report, we identify the physical parameters of the materials that maximize fluid stability and bead transport and minimize solution carryover. We found that fluid stability is maximized with ≤0.8 mm i.d. tubing, valve fluids of similar density to the adjacent solutions, and tubing with ≤20 dyn/cm surface energy. Maximizing bead transport was achieved using ≥2.4 mm i.d. tubing, mineral oil valve fluid, and a mass of 1-3 mg beads. The amount of solution carryover across a surface tension valve was minimized using ≤0.2 mg of beads, tubing with ≤20 dyn/cm surface energy, and air separators. The most favorable parameter space for valve stability and bead transport was identified by combining our experimental results into a single plot using two dimensionless numbers. A strategy is presented for developing additional self-contained assays based on magnetic beads and surface tension valves for low-resource diagnostic applications. PMID:24403996

Normalization of mass cytometry data with bead standards

PubMed Central

Finck, Rachel; Simonds, Erin F.; Jager, Astraea; Krishnaswamy, Smita; Sachs, Karen; Fantl, Wendy; Pe’er, Dana; Nolan, Garry P.; Bendall, Sean C.

2013-01-01

Mass cytometry uses atomic mass spectrometry combined with isotopically pure reporter elements to currently measure as many as 40 parameters per single cell. As with any quantitative technology, there is a fundamental need for quality assurance and normalization protocols. In the case of mass cytometry, the signal variation over time due to changes in instrument performance combined with intervals between scheduled maintenance must be accounted for and then normalized. Here, samples were mixed with polystyrene beads embedded with metal lanthanides, allowing monitoring of mass cytometry instrument performance over multiple days of data acquisition. The protocol described here includes simultaneous measurements of beads and cells on the mass cytometer, subsequent extraction of the bead-based signature, and the application of an algorithm enabling correction of both short- and long-term signal fluctuations. The variation in the intensity of the beads that remains after normalization may also be used to determine data quality. Application of the algorithm to a one-month longitudinal analysis of a human peripheral blood sample reduced the range of median signal fluctuation from 4.9-fold to 1.3-fold. PMID:23512433

Detection of magnetic microbeads and ferrofluid with giant magnetoresistance sensors

NASA Astrophysics Data System (ADS)

Feng, J.; Wang, Y. Q.; Li, F. Q.; Shi, H. P.; Chen, X.

2011-01-01

Giant magnetoresistance sensors based on multilayers [Cu/NiFeCo]×10/ Ta were fabricated by microfabrication technology. A GMR-bridge was used to detect the magnetic MyOne beads and Ferro fluid. The dependence of the GMR-bridge signals on the surface coverage of MyOne beads was studied. The results show that the GMR sensor is capable of detecting the magnetic beads. The detectable limit of MyOne beads is about 100, and the corresponding signal output is 8 μV. The GMR bridge signal is proportional to the surface coverage of the MyOne beads. The sensitivity of the GMR bridge is inversely proportional to the feature size of the GMR sensor. The GMR bridge integrated with microfludic channel was also used for dynamic detection of ferrofluid (suspension of Fe3O4 particles). The results show that the GMR bridge is capable of detecting the flow of ferrofluid, and the sensor signals are proportional to the concentration of the ferrofluid. The detection limit of concentration of the ferrofluid is 0.56 mg/ml, and the corresponding signal is 6.2 μV.

System and method for a parallel immunoassay system

DOEpatents

Stevens, Fred J.

2002-01-01

A method and system for detecting a target antigen using massively parallel immunoassay technology. In this system, high affinity antibodies of the antigen are covalently linked to small beads or particles. The beads are exposed to a solution containing DNA-oligomer-mimics of the antigen. The mimics which are reactive with the covalently attached antibody or antibodies will bind to the appropriate antibody molecule on the bead. The particles or beads are then washed to remove any unbound DNA-oligomer-mimics and are then immobilized or trapped. The bead-antibody complexes are then exposed to a test solution which may contain the targeted antigens. If the antigen is present it will replace the mimic since it has a greater affinity for the respective antibody. The particles are then removed from the solution leaving a residual solution. This residual solution is applied a DNA chip containing many samples of complimentary DNA. If the DNA tag from a mimic binds with its complimentary DNA, it indicates the presence of the target antigen. A flourescent tag can be used to more easily identify the bound DNA tag.

Improved Proteomic Analysis Following Trichloroacetic Acid Extraction of Bacillus anthracis Spore Proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaiser, Brooke LD; Wunschel, David S.; Sydor, Michael A.

2015-08-07

Proteomic analysis of bacterial samples provides valuable information about cellular responses and functions under different environmental pressures. Proteomic analysis is dependent upon efficient extraction of proteins from bacterial samples without introducing bias toward extraction of particular protein classes. While no single method can recover 100% of the bacterial proteins, selected protocols can improve overall protein isolation, peptide recovery, or enrich for certain classes of proteins. The method presented here is technically simple and does not require specialized equipment such as a mechanical disrupter. Our data reveal that for particularly challenging samples, such as B. anthracis Sterne spores, trichloroacetic acid extractionmore » improved the number of proteins identified within a sample compared to bead beating (714 vs 660, respectively). Further, TCA extraction enriched for 103 known spore specific proteins whereas bead beating resulted in 49 unique proteins. Analysis of C. botulinum samples grown to 5 days, composed of vegetative biomass and spores, showed a similar trend with improved protein yields and identification using our method compared to bead beating. Interestingly, easily lysed samples, such as B. anthracis vegetative cells, were equally as effectively processed via TCA and bead beating, but TCA extraction remains the easiest and most cost effective option. As with all assays, supplemental methods such as implementation of an alternative preparation method may provide additional insight to the protein biology of the bacteria being studied.« less

Single-Cell, Multiplexed Protein Detection of Rare Tumor Cells Based on a Beads-on-Barcode Antibody Microarray.

PubMed

Yang, Liu; Wang, Zhihua; Deng, Yuliang; Li, Yan; Wei, Wei; Shi, Qihui

2016-11-15

Circulating tumor cells (CTCs) shed from tumor sites and represent the molecular characteristics of the tumor. Besides genetic and transcriptional characterization, it is important to profile a panel of proteins with single-cell precision for resolving CTCs' phenotype, organ-of-origin, and drug targets. We describe a new technology that enables profiling multiple protein markers of extraordinarily rare tumor cells at the single-cell level. This technology integrates a microchip consisting of 15000 60 pL-sized microwells and a novel beads-on-barcode antibody microarray (BOBarray). The BOBarray allows for multiplexed protein detection by assigning two independent identifiers (bead size and fluorescent color) of the beads to each protein. Four bead sizes (1.75, 3, 4.5, and 6 μm) and three colors (blue, green, and yellow) are utilized to encode up to 12 different proteins. The miniaturized BOBarray can fit an array of 60 pL-sized microwells that isolate single cells for cell lysis and the subsequent detection of protein markers. An enclosed 60 pL-sized microchamber defines a high concentration of proteins released from lysed single cells, leading to single-cell resolution of protein detection. The protein markers assayed in this study include organ-specific markers and drug targets that help to characterize the organ-of-origin and drug targets of isolated rare tumor cells from blood samples. This new approach enables handling a very small number of cells and achieves single-cell, multiplexed protein detection without loss of rare but clinically important tumor cells.

Controlled ice nucleation using freeze-dried Pseudomonas syringae encapsulated in alginate beads.

PubMed

Weng, Lindong; Tessier, Shannon N; Swei, Anisa; Stott, Shannon L; Toner, Mehmet

2017-04-01

The control of ice nucleation is of fundamental significance in many process technologies related to food and pharmaceutical science and cryobiology. Mechanical perturbation, electromagnetic fields and ice-nucleating agents (INAs) have been known to induce ice nucleation in a controlled manner. But these ice-nucleating methods may suffer from cumbersome manual operations, safety concerns of external fields, and biocompatibility and recovery issues of INA particles, especially when used in living systems. Given the automatic ice-seeding nature of INAs, a promising solution to overcome some of the above limitations is to engineer a biocomposite that accommodates the INA particles but minimizes their interactions with biologics, as well as enabling the recovery of used particles. In this study, freeze-dried Pseudomonas syringae, a model ice-nucleating agent, was encapsulated into microliter-sized alginate beads. We evaluated the performance of the bacterial hydrogel beads to initiate ice nucleation in water and aqueous glycerol solution by investigating factors including the size and number of the beads and the local concentration of INA particles. In the aqueous sample of a fixed volume, the total mass of the INA particles (m) was found to be the governing parameter that is solely responsible for determining the ice nucleation performance of the bacterial hydrogel beads. The freezing temperature has a strong positive linear correlation with log 10 m. The findings in this study provide an effective, predictable approach to control ice nucleation, which can improve the outcome and standardization of many ice-assisted process technologies. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantitative Single-Cell mRNA Analysis in Hydrogel Beads.

PubMed

Rakszewska, Agata; Stolper, Rosa J; Kolasa, Anna B; Piruska, Aigars; Huck, Wilhelm T S

2016-06-01

In recent years, technologies capable of analyzing single cells have emerged that are transforming many fields of biological research. Herein we report how DNA-functionalized hydrogel beads can serve as a matrix to capture mRNA from lysed single cells. mRNA quantification free of pre-amplification bias is ensured by using padlock probes and rolling circle amplification followed by hybridization with fluorescent probes. The number of transcripts in individual cells is assessed by simply counting fluorescent dots inside gel beads. The method extends the potential of existing techniques and provides a general platform for capturing molecules of interest from single cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bead-based microfluidic immunoassay for diagnosis of Johne's disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wadhwa, Ashutosh; Foote, Robert; Shaw, Robert W

2012-01-01

Microfluidics technology offers a platform for development of point-of-care diagnostic devices for various infectious diseases. In this study, we examined whether serodiagnosis of Johne s disease (JD) can be conducted in a bead-based microfluidic assay system. Magnetic micro-beads were coated with antigens of the causative agent of JD, Mycobacterium avium subsp. paratuberculosis. The antigen-coated beads were incubated with serum samples of JD-positive or negative serum samples and then with a fluorescently-labeled secondary antibody (SAB). To confirm binding of serum antibodies to the antigen, the beads were subjected to flow cytometric analysis. Different conditions (dilutions of serum and SAB, types ofmore » SAB, and types of magnetic beads) were optimized for a great degree of differentiation between the JD-negative and JD-positive samples. Using the optimized conditions, we tested a well-classified set of 155 serum samples from JD negative and JD-positive cattle by using the bead-based flow cytometric assay. Of 105 JD-positive samples, 63 samples (60%) showed higher antibody binding levels than a cut-off value determined by using antibody binding levels of JD-negative samples. In contrast, only 43-49 JD-positive samples showed higher antibody binding levels than the cut-off value when the samples were tested by commercially-available immunoassays. Microfluidic assays were performed by magnetically immobilizing a number of beads within a microchannel of a glass microchip and detecting antibody on the collected beads by laser-induced fluorescence. Antigen-coated magnetic beads treated with bovine serum sample and fluorescently-labeled SAB were loaded into a microchannel to measure the fluorescence (reflecting level of antibody binding) on the beads in the microfluidic system. When the results of five bovine serum samples obtained with the system were compared to those obtained with the flow cytometer, a high level of correlation (linear regression, r2 = 0.994) was observed. In a further experiment, we magnetically immobilized antigen-coated beads in a microchannel, reacted the beads with serum and SAB in the channel, and detected antibody binding to the beads in the microfluidic system. A strong antibody binding in JD-positive serum was detected, whereas there was only negligible binding in negative control experiments. Our data suggest that the bead-based microfluidic system may form a basis for development of an on-site serodiagnosis of JD. Key Words: Mycobacterium avium ssp. paratuberculosis, Johne s disease, microfluidics, lab-on-a-chip.« less

Accurate multiplex polony sequencing of an evolved bacterial genome.

PubMed

Shendure, Jay; Porreca, Gregory J; Reppas, Nikos B; Lin, Xiaoxia; McCutcheon, John P; Rosenbaum, Abraham M; Wang, Michael D; Zhang, Kun; Mitra, Robi D; Church, George M

2005-09-09

We describe a DNA sequencing technology in which a commonly available, inexpensive epifluorescence microscope is converted to rapid nonelectrophoretic DNA sequencing automation. We apply this technology to resequence an evolved strain of Escherichia coli at less than one error per million consensus bases. A cell-free, mate-paired library provided single DNA molecules that were amplified in parallel to 1-micrometer beads by emulsion polymerase chain reaction. Millions of beads were immobilized in a polyacrylamide gel and subjected to automated cycles of sequencing by ligation and four-color imaging. Cost per base was roughly one-ninth as much as that of conventional sequencing. Our protocols were implemented with off-the-shelf instrumentation and reagents.

Synergistic effect of divalent cations in improving technological properties of cross-linked alginate beads.

PubMed

Cerciello, Andrea; Del Gaudio, Pasquale; Granata, Veronica; Sala, Marina; Aquino, Rita P; Russo, Paola

2017-08-01

Gelling solution parameters are some of the most important variables in ionotropic gelation and consequently influence the technological characteristics of the product. To date, only a few studies have focused on the simultaneous use of multiple cations as gelling agents. With the aim to deeply explore this possibility, in this research we investigated the effect of two divalent cations (Ca 2+ and Zn 2+ ) on alginate beads formation and properties. Alginate beads containing prednisolone (P) as model drug were prepared by prilling technique. The main critical variables of the ionotropic gelation process i.e. composition of the aqueous feed solutions (sodium alginate and prednisolone concentration) and cross-linking conditions (Ca 2+ , Zn 2+ or Ca 2+ +Zn 2+ ), were studied. The obtained beads were characterized and their in vitro release performances were assessed in conditions simulating the gastrointestinal environment. Results evidenced a synergistic effect of the two cations, affecting positively both the encapsulation efficiency and the ability of the alginate polymeric matrix to control the drug release. A Ca 2+ /Zn 2+ ratio of 4:1, in fact, exploited the Ca 2+ ability of establish quicker electrostatic interactions with guluronic groups of alginate and the Zn 2+ ability to establish covalent-like bonds with carboxylate groups of both guluronic and mannuronic moieties of alginate. Copyright © 2017 Elsevier B.V. All rights reserved.

New Possibilities in the Fabrication of Hybrid Components with Big Dimensions by Means of Selective Laser Melting (SLM)

NASA Astrophysics Data System (ADS)

Ascari, A.; Fortunato, A.; Liverani, E.; Gamberoni, A.; Tomesani, L.

The application of laser technology to welding of dissimilar AISI316 stainless steel components manufactured with selective laser melting (SLM) and traditional methods has been investigated. The role of laser parameters on weld bead formation has been studied experimentally, with particular attention placed on effects occurring at the interface between the two parts. In order to assess weld bead characteristics, standardised tensile tests were carried out on suitable specimens and the fracture zone was analysed. The results highlighted the possibility of exploiting suitable process parameters to appropriately shape the heat affected and fusion zones in order to maximise the mechanical performance of the component and minimise interactions between the two parent metals in the weld bead.

An Abiotic Glass-Bead Collector Exhibiting Active Transport

NASA Astrophysics Data System (ADS)

Goto, Youhei; Kanda, Masato; Yamamoto, Daigo; Shioi, Akihisa

2015-09-01

Animals relocate objects as needed by active motion. Active transport is ubiquitous in living organisms but has been difficult to realize in abiotic systems. Here we show that a self-propelled droplet can gather scattered beads toward one place on a floor and sweep it clean. This is a biomimetic active transport with loadings and unloadings, because the transport was performed by a carrier and the motion of the carrier was maintained by the energy of the chemical reaction. The oil droplet produced fluctuation of the local number density of the beads on the floor, followed by its autocatalytic growth. This mechanism may inspire the technologies based on active transport wherein chemical and physical substances migrate as in living organisms.

SNP Assay Development for Linkage Map Construction, Anchoring Whole-Genome Sequence, and Other Genetic and Genomic Applications in Common Bean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Qijian; Jia, Gaofeng; Hyten, David L.

A total of 992,682 single-nucleotide polymorphisms (SNPs) was identified as ideal for Illumina Infinium II BeadChip design after sequencing a diverse set of 17 common bean (Phaseolus vulgaris L) varieties with the aid of next-generation sequencing technology. From these, two BeadChips each with >5000 SNPs were designed. The BARCBean6K_1 BeadChip was selected for the purpose of optimizing polymorphism among market classes and, when possible, SNPs were targeted to sequence scaffolds in the Phaseolus vulgaris 14× genome assembly with sequence lengths >10 kb. The BARCBean6K_2 BeadChip was designed with the objective of anchoring additional scaffolds and to facilitate orientation of largemore » scaffolds. Analysis of 267 F2 plants from a cross of varieties Stampede × Red Hawk with the two BeadChips resulted in linkage maps with a total of 7040 markers including 7015 SNPs. With the linkage map, a total of 432.3 Mb of sequence from 2766 scaffolds was anchored to create the Phaseolus vulgaris v1.0 assembly, which accounted for approximately 89% of the 487 Mb of available sequence scaffolds of the Phaseolus vulgaris v0.9 assembly. A core set of 6000 SNPs (BARCBean6K_3 BeadChip) with high genotyping quality and polymorphism was selected based on the genotyping of 365 dry bean and 134 snap bean accessions with the BARCBean6K_1 and BARCBean6K_2 BeadChips. The BARCBean6K_3 BeadChip is a useful tool for genetics and genomics research and it is widely used by breeders and geneticists in the United States and abroad.« less

SNP Assay Development for Linkage Map Construction, Anchoring Whole-Genome Sequence, and Other Genetic and Genomic Applications in Common Bean

DOE PAGES

Song, Qijian; Jia, Gaofeng; Hyten, David L.; ...

2015-08-28

A total of 992,682 single-nucleotide polymorphisms (SNPs) was identified as ideal for Illumina Infinium II BeadChip design after sequencing a diverse set of 17 common bean (Phaseolus vulgaris L) varieties with the aid of next-generation sequencing technology. From these, two BeadChips each with >5000 SNPs were designed. The BARCBean6K_1 BeadChip was selected for the purpose of optimizing polymorphism among market classes and, when possible, SNPs were targeted to sequence scaffolds in the Phaseolus vulgaris 14× genome assembly with sequence lengths >10 kb. The BARCBean6K_2 BeadChip was designed with the objective of anchoring additional scaffolds and to facilitate orientation of largemore » scaffolds. Analysis of 267 F2 plants from a cross of varieties Stampede × Red Hawk with the two BeadChips resulted in linkage maps with a total of 7040 markers including 7015 SNPs. With the linkage map, a total of 432.3 Mb of sequence from 2766 scaffolds was anchored to create the Phaseolus vulgaris v1.0 assembly, which accounted for approximately 89% of the 487 Mb of available sequence scaffolds of the Phaseolus vulgaris v0.9 assembly. A core set of 6000 SNPs (BARCBean6K_3 BeadChip) with high genotyping quality and polymorphism was selected based on the genotyping of 365 dry bean and 134 snap bean accessions with the BARCBean6K_1 and BARCBean6K_2 BeadChips. The BARCBean6K_3 BeadChip is a useful tool for genetics and genomics research and it is widely used by breeders and geneticists in the United States and abroad.« less

SNP Assay Development for Linkage Map Construction, Anchoring Whole-Genome Sequence, and Other Genetic and Genomic Applications in Common Bean.

PubMed

Song, Qijian; Jia, Gaofeng; Hyten, David L; Jenkins, Jerry; Hwang, Eun-Young; Schroeder, Steven G; Osorno, Juan M; Schmutz, Jeremy; Jackson, Scott A; McClean, Phillip E; Cregan, Perry B

2015-08-28

A total of 992,682 single-nucleotide polymorphisms (SNPs) was identified as ideal for Illumina Infinium II BeadChip design after sequencing a diverse set of 17 common bean (Phaseolus vulgaris L) varieties with the aid of next-generation sequencing technology. From these, two BeadChips each with >5000 SNPs were designed. The BARCBean6K_1 BeadChip was selected for the purpose of optimizing polymorphism among market classes and, when possible, SNPs were targeted to sequence scaffolds in the Phaseolus vulgaris 14× genome assembly with sequence lengths >10 kb. The BARCBean6K_2 BeadChip was designed with the objective of anchoring additional scaffolds and to facilitate orientation of large scaffolds. Analysis of 267 F2 plants from a cross of varieties Stampede × Red Hawk with the two BeadChips resulted in linkage maps with a total of 7040 markers including 7015 SNPs. With the linkage map, a total of 432.3 Mb of sequence from 2766 scaffolds was anchored to create the Phaseolus vulgaris v1.0 assembly, which accounted for approximately 89% of the 487 Mb of available sequence scaffolds of the Phaseolus vulgaris v0.9 assembly. A core set of 6000 SNPs (BARCBean6K_3 BeadChip) with high genotyping quality and polymorphism was selected based on the genotyping of 365 dry bean and 134 snap bean accessions with the BARCBean6K_1 and BARCBean6K_2 BeadChips. The BARCBean6K_3 BeadChip is a useful tool for genetics and genomics research and it is widely used by breeders and geneticists in the United States and abroad. Copyright © 2015 Song et al.

High-speed RNA microextraction technology using magnetic oligo-dT beads and lateral magnetophoresis.

PubMed

Lee, Hwanyong; Jung, Jinhee; Han, Song-I; Han, Ki-Ho

2010-10-21

This paper presents a high-speed RNA microextractor for the direct isolation of RNA from peripheral blood lysate using magnetic oligo-dT beads. The extraction is achieved through lateral magnetophoresis, generated by a ferromagnetic wire array inlaid on a glass substrate. This RNA microextractor separated more than 80% of magnetic beads with a flow rate up to 20 ml h(-1), and the overall extraction procedure was completed within 1 min. The absorbance ratio of RNA to protein (A(260)/A(280)) was >1.7, indicating that the extraction technology yielded nearly pure RNA. The feasibility of this technique was evaluated further for its applicability to reverse transcription polymerase chain reaction (RT-PCR) procedures by performing cDNA synthesis and PCR. The analysis verified that the RNA microextractor is a practical method for easy, rapid, and high-precision RT-PCR using minimal reagent volumes without requiring highly trained personnel. In addition, it can be readily incorporated into genetic analysis procedures for realizing automated on-chip genetic platforms in a micro format.

Comparison of pre-processing methods for multiplex bead-based immunoassays.

PubMed

Rausch, Tanja K; Schillert, Arne; Ziegler, Andreas; Lüking, Angelika; Zucht, Hans-Dieter; Schulz-Knappe, Peter

2016-08-11

High throughput protein expression studies can be performed using bead-based protein immunoassays, such as the Luminex® xMAP® technology. Technical variability is inherent to these experiments and may lead to systematic bias and reduced power. To reduce technical variability, data pre-processing is performed. However, no recommendations exist for the pre-processing of Luminex® xMAP® data. We compared 37 different data pre-processing combinations of transformation and normalization methods in 42 samples on 384 analytes obtained from a multiplex immunoassay based on the Luminex® xMAP® technology. We evaluated the performance of each pre-processing approach with 6 different performance criteria. Three performance criteria were plots. All plots were evaluated by 15 independent and blinded readers. Four different combinations of transformation and normalization methods performed well as pre-processing procedure for this bead-based protein immunoassay. The following combinations of transformation and normalization were suitable for pre-processing Luminex® xMAP® data in this study: weighted Box-Cox followed by quantile or robust spline normalization (rsn), asinh transformation followed by loess normalization and Box-Cox followed by rsn.

Reduction of Cr(6+) to Cr(3+) in a packed-bed bioreactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turick, C.E.; Apel, W.A.; Camp, C.E.

1997-12-31

Hexavalent chromium, Cr(6{sup +}), is a common and toxic pollutant in soils and waters. Reduction of the mobile Cr(6{sup +}) to the less mobile and less toxic trivalent chromium, Cr(3{sup +}), can be achieved with conventional chemical reduction technologies. Alternatively, Cr(6{sup +}) can be biochemically reduced to Cr(3{sup +}) by anaerobic microbial consortia which appear to use Cr(6{sup +}) as a terminal electron acceptor. A bioprocess for Cr(6{sup +}) reduction has been demonstrated using a packed-bed bioreactor containing ceramic packing, and then compared to a similar bioreactor containing DuPont Bio-Sep beads. An increase in volumetric productivity from 4 mg Cr(6{supmore » +})/L/h to 260 mg Cr(6{sup +})/L/h, probably due to an increase in biomass density, was obtained using Bio-Sep beads. The beads contain internal macropores which were shown by scanning electron microscopy to house dense concentrations of bacteria. Comparisons to conventional Cr(6{sup +}) treatment technologies indicate that a bioprocess has several economic and operational advantages. 7 refs., 4 figs.« less

Motion-Based Immunological Detection of Zika Virus Using Pt-Nanomotors and a Cellphone.

PubMed

Draz, Mohamed Shehata; Lakshminaraasimulu, Nivethitha Kota; Krishnakumar, Sanchana; Battalapalli, Dheerendranath; Vasan, Anish; Kanakasabapathy, Manoj Kumar; Sreeram, Aparna; Kallakuri, Shantanu; Thirumalaraju, Prudhvi; Li, Yudong; Hua, Stephane; Yu, Xu G; Kuritzkes, Daniel R; Shafiee, Hadi

2018-05-16

Zika virus (ZIKV) infection is an emerging pandemic threat to humans that can be fatal in newborns. Advances in digital health systems and nanoparticles can facilitate the development of sensitive and portable detection technologies for timely management of emerging viral infections. Here we report a nanomotor-based bead-motion cellphone (NBC) system for the immunological detection of ZIKV. The presence of virus in a testing sample results in the accumulation of platinum (Pt)-nanomotors on the surface of beads, causing their motion in H 2 O 2 solution. Then the virus concentration is detected in correlation with the change in beads motion. The developed NBC system was capable of detecting ZIKV in samples with virus concentrations as low as 1 particle/μL. The NBC system allowed a highly specific detection of ZIKV in the presence of the closely related dengue virus and other neurotropic viruses, such as herpes simplex virus type 1 and human cytomegalovirus. The NBC platform technology has the potential to be used in the development of point-of-care diagnostics for pathogen detection and disease management in developed and developing countries.

Thick resist for MEMS processing

NASA Astrophysics Data System (ADS)

Brown, Joe; Hamel, Clifford

2001-11-01

The need for technical innovation is always present in today's economy. Microfabrication methods have evolved in support of the demand for smaller and faster integrated circuits with price performance improvements always in the scope of the manufacturing design engineer. The dispersion of processing technology spans well beyond IC fabrication today with batch fabrication and wafer scale processing lending advantages to MEMES applications from biotechnology to consumer electronics from oil exploration to aerospace. Today the demand for innovative processing techniques that enable technology is apparent where only a few years ago appeared too costly or not reliable. In high volume applications where yield and cost improvements are measured in fractions of a percent it is imperative to have process technologies that produce consistent results. Only a few years ago thick resist coatings were limited to thickness less than 20 microns. Factors such as uniformity, edge bead and multiple coatings made high volume production impossible. New developments in photoresist formulation combined with advanced coating equipment techniques that closely controls process parameters have enable thick photoresist coatings of 70 microns with acceptable uniformity and edge bead in one pass. Packaging of microelectronic and micromechanical devices is often a significant cost factor and a reliability issue for high volume low cost production. Technologies such as flip- chip assembly provide a solution for cost and reliability improvements over wire bond techniques. The processing for such technology demands dimensional control and presents a significant cost savings if it were compatible with mainstream technologies. Thick photoresist layers, with good sidewall control would allow wafer-bumping technologies to penetrate the barriers to yield and production where costs for technology are the overriding issue. Single pass processing is paramount to the manufacturability of packaging technology. Uniformity and edge bead control defined the success of process implementation. Today advanced packaging solutions are created with thick photoresist coatings. The techniques and results will be presented.

Detection of Nosema bombycis by FTA cards and loop-mediated isothermal amplification (LAMP).

PubMed

Yan, Wei; Shen, Zhongyuan; Tang, Xudong; Xu, Li; Li, Qianlong; Yue, Yajie; Xiao, Shengyan; Fu, Xuliang

2014-10-01

We successfully established a detection method which exhibited a markedly higher sensitivity than previously developed detection methods for Nosema bombycis by combining glass beads, FTA card, and LAMP. Spores of N. bombycis were first broken by acid-washed glass beads; the DNA was subsequently extracted and purified with the FTA card, and LAMP was performed using primers (LSU296) designed based on the sequence of the LSU rRNA of N. bombycis. The minimum detection concentration was 10 spores/mL. When this method was used to detect pebrine disease in silkworm egg, the detection rate for 500 silkworm eggs, in which only one egg was infected with N. bombycis, was 100 % under our optimized conditions. If the number of eggs in the sample increased to 800 or 1,000, the sample was divided into two equal portions, and the eggs were smashed with glass beads after the addition of 1 mL of TE buffer. The liquid in two tubes was later mixed and applied to the FTA card, and the detection rates were 100 %. Furthermore, the LAMP method established in our study could detect N. bombycis infection in silkworm 24 h earlier than microscopy.

Cell-based delivery of glucagon-like peptide-1 using encapsulated mesenchymal stem cells.

PubMed

Wallrapp, Christine; Thoenes, Eric; Thürmer, Frank; Jork, Anette; Kassem, Moustapha; Geigle, Peter

2013-01-01

Glucagon-like peptide-1 (GLP-1) CellBeads are cell-based implants for the sustained local delivery of bioactive factors. They consist of GLP-1 secreting mesenchymal stem cells encapsulated in a spherically shaped immuno-isolating alginate matrix. A highly standardized and reproducible encapsulation method is described for the manufacturing of homogeneous CellBeads. Viability and sustained secretion was shown for the recombinant GLP-1 and the cell endogenous bioactive factors like vascular endothelial growth factor, neurotrophin 3 (NT-3) and glial cell line-derived neurotrophic factor. Manufacturing and quality control is performed in compliance with good manufacturing practice and fulfils all regulatory requirements for human clinical use. GLP-1 CellBeads combine the neuro- and cardioprotective properties of both GLP-1 and mesenchymal stem cells. First promising results were obtained from preclinical studies and an ongoing safety trial in humans but further studies have to prove the overall potential of CellBead technology in cell-based regenerative medicine.

Rapid and continuous magnetic separation in droplet microfluidic devices.

PubMed

Brouzes, Eric; Kruse, Travis; Kimmerling, Robert; Strey, Helmut H

2015-02-07

We present a droplet microfluidic method to extract molecules of interest from a droplet in a rapid and continuous fashion. We accomplish this by first marginalizing functionalized super-paramagnetic beads within the droplet using a magnetic field, and then splitting the droplet into one droplet containing the majority of magnetic beads and one droplet containing the minority fraction. We quantitatively analysed the factors which affect the efficiency of marginalization and droplet splitting to optimize the enrichment of magnetic beads. We first characterized the interplay between the droplet velocity and the strength of the magnetic field and its effect on marginalization. We found that marginalization is optimal at the midline of the magnet and that marginalization is a good predictor of bead enrichment through splitting at low to moderate droplet velocities. Finally, we focused our efforts on manipulating the splitting profile to improve the enrichment provided by asymmetric splitting. We designed asymmetric splitting forks that employ capillary effects to preferentially extract the bead-rich regions of the droplets. Our strategy represents a framework to optimize magnetic bead enrichment methods tailored to the requirements of specific droplet-based applications. We anticipate that our separation technology is well suited for applications in single-cell genomics and proteomics. In particular, our method could be used to separate mRNA bound to poly-dT functionalized magnetic microparticles from single cell lysates to prepare single-cell cDNA libraries.

Optimization of process parameters of pulsed TIG welded maraging steel C300

NASA Astrophysics Data System (ADS)

Deepak, P.; Jualeash, M. J.; Jishnu, J.; Srinivasan, P.; Arivarasu, M.; Padmanaban, R.; Thirumalini, S.

2016-09-01

Pulsed TIG welding technology provides excellent welding performance on thin sections which helps to increase productivity, enhance weld quality, minimize weld costs, and boost operator efficiency and this has drawn the attention of the welding society. Maraging C300 steel is extensively used in defence and aerospace industry and thus its welding becomes an area of paramount importance. In pulsed TIG welding, weld quality depends on the process parameters used. In this work, Pulsed TIG bead-on-plate welding is performed on a 5mm thick maraging C300 plate at different combinations of input parameters: peak current (Ip), base current (Ib) and pulsing frequency (HZ) as per box behnken design with three-levels for each factor. Response surface methodology is utilized for establishing a mathematical model for predicting the weld bead depth. The effect of Ip, Ib and HZ on the weld bead depth is investigated using the developed model. The weld bead depth is found to be affected by all the three parameters. Surface and contour plots developed from regression equation are used to optimize the processing parameters for maximizing the weld bead depth. Optimum values of Ip, Ib and HZ are obtained as 259 A, 120 A and 8 Hz respectively. Using this optimum condition, maximum bead depth of the weld is predicted to be 4.325 mm.

Rapid and continuous magnetic separation in droplet microfluidic devices

PubMed Central

Brouzes, Eric; Kruse, Travis; Kimmerling, Robert; Strey, Helmut H.

2015-01-01

We present a droplet microfluidic method to extract molecules of interest from a droplet in a rapid and continuous fashion. We accomplish this by first marginalizing functionalized super-paramagnetic beads within the droplet using a magnetic field, and then splitting the droplet into one droplet containing the majority of magnetic beads and one droplet containing the minority fraction. We quantitatively analysed the factors which affect the efficiency of marginalization and droplet splitting to optimize the enrichment of magnetic beads. We first characterized the interplay between the droplet velocity and the strength of the magnetic field and its effect on marginalization. We found that marginalization is optimal at the midline of the magnet and that marginalization is a good predictor of bead enrichment through splitting at low to moderate droplet velocities. Finally, we focused our efforts on manipulating the splitting profile to improve the enrichment provided by asymmetric splitting. We designed asymmetric splitting forks that employ capillary effects to preferentially extract the bead-rich regions of the droplets. Our strategy represents a framework to optimize magnetic bead enrichment methods tailored to the requirements of specific droplet-based applications. We anticipate that our separation technology is well suited for applications in single-cell genomics and proteomics. In particular, our method could be used to separate mRNA bound to poly-dT functionalized magnetic microparticles from single cell lysates to prepare single-cell cDNA libraries. PMID:25501881

Cloning and Identification of Recombinant Argonaute-Bound Small RNAs Using Next-Generation Sequencing.

PubMed

Gangras, Pooja; Dayeh, Daniel M; Mabin, Justin W; Nakanishi, Kotaro; Singh, Guramrit

2018-01-01

Argonaute proteins (AGOs) are loaded with small RNAs as guides to recognize target mRNAs. Since the target specificity heavily depends on the base complementarity between two strands, it is important to identify small guide and long target RNAs bound to AGOs. For this purpose, next-generation sequencing (NGS) technologies have extended our appreciation truly to the nucleotide level. However, the identification of RNAs via NGS from scarce RNA samples remains a challenge. Further, most commercial and published methods are compatible with either small RNAs or long RNAs, but are not equally applicable to both. Therefore, a single method that yields quantitative, bias-free NGS libraries to identify small and long RNAs from low levels of input will be of wide interest. Here, we introduce such a procedure that is based on several modifications of two published protocols and allows robust, sensitive, and reproducible cloning and sequencing of small amounts of RNAs of variable lengths. The method was applied to the identification of small RNAs bound to a purified eukaryotic AGO. Following ligation of a DNA adapter to RNA 3'-end, the key feature of this method is to use the adapter for priming reverse transcription (RT) wherein biotinylated deoxyribonucleotides specifically incorporated into the extended complementary DNA. Such RT products are enriched on streptavidin beads, circularized while immobilized on beads and directly used for PCR amplification. We provide a stepwise guide to generate RNA-Seq libraries, their purification, quantification, validation, and preparation for next-generation sequencing. We also provide basic steps in post-NGS data analyses using Galaxy, an open-source, web-based platform.

Mixed-mode ion exchange-based integrated proteomics technology for fast and deep plasma proteome profiling.

PubMed

Xue, Lu; Lin, Lin; Zhou, Wenbin; Chen, Wendong; Tang, Jun; Sun, Xiujie; Huang, Peiwu; Tian, Ruijun

2018-06-09

Plasma proteome profiling by LC-MS based proteomics has drawn great attention recently for biomarker discovery from blood liquid biopsy. Due to standard multi-step sample preparation could potentially cause plasma protein degradation and analysis variation, integrated proteomics sample preparation technologies became promising solution towards this end. Here, we developed a fully integrated proteomics sample preparation technology for both fast and deep plasma proteome profiling under its native pH. All the sample preparation steps, including protein digestion and two-dimensional fractionation by both mixed-mode ion exchange and high-pH reversed phase mechanism were integrated into one spintip device for the first time. The mixed-mode ion exchange beads design achieved the sample loading at neutral pH and protein digestion within 30 min. Potential sample loss and protein degradation by pH changing could be voided. 1 μL of plasma sample with depletion of high abundant proteins was processed by the developed technology with 12 equally distributed fractions and analyzed with 12 h of LC-MS gradient time, resulting in the identification of 862 proteins. The combination of the Mixed-mode-SISPROT and data-independent MS method achieved fast plasma proteome profiling in 2 h with high identification overlap and quantification precision for a proof-of-concept study of plasma samples from 5 healthy donors. We expect that the Mixed-mode-SISPROT become a generally applicable sample preparation technology for clinical oriented plasma proteome profiling. Copyright © 2018 Elsevier B.V. All rights reserved.

Capture of dengue viruses using antibody-integrated graphite-encapsulated magnetic beads produced using gas plasma technology

PubMed Central

SAKUDO, AKIKAZU; VISWAN, ANCHU; CHOU, HAN; SASAKI, TADAHIRO; IKUTA, KAZUYOSHI; NAGATSU, MASAAKI

2016-01-01

Despite significant advances in medicine, global health is threatened by emerging infectious diseases caused by a number of viruses. Dengue virus (DENV) is a mosquito-borne virus, which can be transmitted to humans via mosquito vectors. Previously, the Ministry of Health, Labour and Welfare in Japan reported the country's first domestically acquired case of dengue fever for almost 70 years. To address this issue, it is important to develop novel technologies for the sensitive detection of DENV. The present study reported on the development of plasma-functionalized, graphite-encapsulated magnetic nanoparticles (GrMNPs) conjugated with anti-DENV antibody for DENV capture. Radiofrequency wave-excited inductively-coupled Ar and ammonia gas plasmas were used to introduce amino groups onto the surface of the GrMNPs. The GrMNPs were then conjugated with an antibody against DENV, and the antibody-integrated magnetic beads were assessed for their ability to capture DENV. Beads incubated in a cell culture medium of DENV-infected mosquito cells were separated from the supernatant by applying a magnetic field and were then washed. The adsorption of DENV serotypes 1–4 onto the beads was confirmed using reverse transcription-polymerase chain reaction, which detected the presence of DENV genomic RNA on the GrMNPs. The methodology described in the present study, which employed the plasma-functionalization of GrMNPs to enable antibody-integration, represents a significant improvement in the detection of DENV. PMID:27221214

Black holes as beads on cosmic strings

NASA Astrophysics Data System (ADS)

Ashoorioon, Amjad; Mann, Robert B.

2014-11-01

We consider the possibility of the formation of cosmic strings with black holes as beads. We focus on the simplest setup where two black holes are formed on a long cosmic string. It turns out that in the absence of a background magnetic field and for observationally viable values for cosmic string tensions, μ \\lt 2× {{10}-7}, the tension of the strut in between the black holes has to be less than the ones that run into infinity. This result does not change if a cosmological constant is present. However, if a background magnetic field is turned on, we can have stable setups where the tensions of all cosmic strings are equal. We derive the equilibrium conditions in each of these setups depending on whether the black holes are extremal or non-extremal. We obtain cosmologically acceptable solutions with solar mass black holes and an intragalactic-strength cosmic magnetic field.

High-volume extraction of nucleic acids by magnetic bead technology for ultrasensitive detection of bacteria in blood components.

PubMed

Störmer, Melanie; Kleesiek, Knut; Dreier, Jens

2007-01-01

Nucleic acid isolation, the most technically demanding and laborious procedure performed in molecular diagnostics, harbors the potential for improvements in automation. A recent development is the use of magnetic beads covered with nucleic acid-binding matrices. We adapted this technology with a broad-range 23S rRNA real-time reverse transcription (RT)-PCR assay for fast and sensitive detection of bacterial contamination of blood products. We investigated different protocols for an automated high-volume extraction method based on magnetic-separation technology for the extraction of bacterial nucleic acids from platelet concentrates (PCs). We added 2 model bacteria, Staphylococcus epidermidis and Escherichia coli, to a single pool of apheresis-derived, single-donor platelets and assayed the PCs by real-time RT-PCR analysis with an improved primer-probe system and locked nucleic acid technology. Co-amplification of human beta(2)-microglobulin mRNA served as an internal control (IC). We used probit analysis to calculate the minimum concentration of bacteria that would be detected with 95% confidence. For automated magnetic bead-based extraction technology with the real-time RT-PCR, the 95% detection limit was 29 x 10(3) colony-forming units (CFU)/L for S. epidermidis and 22 x 10(3) CFU/L for E. coli. No false-positive results occurred, either due to nucleic acid contamination of reagents or externally during testing of 1030 PCs. High-volume nucleic acid extraction improved the detection limit of the assay. The improvement of the primer-probe system and the integration of an IC make the RT-PCR assay appropriate for bacteria screening of platelets.

A Comparison Between Mechanical And Electrochemical Tests on Ti6Al4V Welded By LBW

NASA Astrophysics Data System (ADS)

Serroni, G.; Bitondo, C.; Astarita, A.; Scala, A.; Gloria, A.; Prisco, U.; Squillace, A.; Bellucci, F.

2011-05-01

Titanium and its alloys are nowadays widely used in many sectors: in the medical field (orthopedic and dental ones), in the architectural field, in the chemical plants field and in aeronautic. In this last field it is more and more used both for its contribution to make lightweight and time durable structures and for its compatibility with new materials, first of all Carbon Fiber Reinforced Plastics (CFRP). To this aim, lots of researches are now focusing on new and emerging technologies capable to make titanium objects and, at the same time, reducing the scrap, since titanium alloys for aeronautic application are very expensive. This paper examines Grade 5 Titanium Alloy (Ti6Al4V) welded by Laser Beam (LBW) in butt-joint configuration. The source was Nd:YAG laser, moreover two inert gases were used, in order to provide a shield both on the top and on the bottom of the weld bead. The joints were studied by varying two process parameters: welding speed and power of the laser beam. It was not possible to realize a full experimental plan, due to technological limits in making titanium laser beam welds. The joints were tested to measure their mechanical properties and the corrosion resistance. The process parameters do not significantly affect the maximum static strength of the joints. Microscopic analysis showed that welds made with high power and low welding speed have a uniform weld bead, and no macroscopic defect occurs. Fatigue test results, instead, show a marked influence of the morphology of the weld bead: the occurrence of some defects, such as the undercut, both on the top and on the bottom of the weld bead, dramatically reduced fatigue resistance of the joints. Corrosion resistance was studied using the electrochemical micro cell technique, which allows to distinguish electrochemical properties of each zone of the weld bead, even when, as in this case, they are very narrow. By a general point of view, it has been demonstrated that the joints showing the best mechanical performances also possess better electrochemical properties. What's more, in these cases, the weld bead shows a cathodic behavior with respect to the parent material.

Rapid and continuous magnetic separation in droplet microfluidic devices

DOE PAGES

Brouzes, Eric; Kruse, Travis; Kimmerling, Robert; ...

2014-12-03

Here, we present a droplet microfluidic method to extract molecules of interest from a droplet in a rapid and continuous fashion. We accomplish this by first marginalizing functionalized super-paramagnetic beads within the droplet using a magnetic field, and then splitting the droplet into one droplet containing the majority of magnetic beads and one droplet containing the minority fraction. We quantitatively analysed the factors which affect the efficiency of marginalization and droplet splitting to optimize the enrichment of magnetic beads. We first characterized the interplay between the droplet velocity and the strength of the magnetic field and its effect on marginalization.more » We found that marginalization is optimal at the midline of the magnet and that marginalization is a good predictor of bead enrichment through splitting at low to moderate droplet velocities. Finally, we focused our efforts on manipulating the splitting profile to improve the enrichment provided by asymmetric splitting. We designed asymmetric splitting forks that employ capillary effects to preferentially extract the bead-rich regions of the droplets. Our strategy represents a framework to optimize magnetic bead enrichment methods tailored to the requirements of specific droplet-based applications. We anticipate that our separation technology is well suited for applications in single-cell genomics and proteomics. In particular, our method could be used to separate mRNA bound to poly-dT functionalized magnetic microparticles from single cell lysates to prepare single-cell cDNA libraries.« less

Impact of plant growth-promoting rhizobacteria on root colonization potential and life cycle of Rhizophagus irregularis following co-entrapment into alginate beads.

PubMed

Loján, P; Demortier, M; Velivelli, S L S; Pfeiffer, S; Suárez, J P; de Vos, P; Prestwich, B D; Sessitsch, A; Declerck, S

2017-02-01

This study aimed at evaluating the impact of seven plant growth-promoting rhizobacteria (PGPR) on root colonization and life cycle of Rhizophagus irregularis MUCL 41833 when co-entrapped in alginate beads. Two in vitro experiments were conducted. The first consisted of the immobilization of R. irregularis and seven PGPR isolates into alginate beads to assess the effect of the bacteria on the pre-symbiotic growth of the fungus. In the second experiment, the best performing PGPR from experiment 1 was tested for its ability to promote the symbiotic development of the AMF in potato plantlets from three cultivars. Results showed that only one isolate identified as Pseudomonas plecoglossicida (R-67094) promoted germ tube elongation and hyphal branching of germinated spores during the pre-symbiotic phase of the fungus. This PGPR further promoted the symbiotic development of the AMF in potato plants. The co-entrapment of Ps. plecoglossicida R-67094 and R. irregularis MUCL 41833 in alginate beads improved root colonization by the AMF and its further life cycle under the experimental conditions. Co-entrapment of suitable AMF-PGPR combinations within alginate beads may represent an innovative technology that can be fine-tuned for the development of efficient consortia-based bioformulations. © 2016 The Society for Applied Microbiology.

Overcoming Resistance to Inhibitors of the Akt Protein Kinase by Modulation of the Pim Kinase Pathway

DTIC Science & Technology

2017-01-01

regulated by Pim and what is the outcome of treating animals with Pim inhibitors. To explore these tasks we first stained human tumor and normal samples ...Sepharose beads. The beads were incubated with 100 ng of purified Pim-1 proteins at 37 °C for 30 minutes. Samples were analyzed by immunoblot assays using...secreted by these cells using novel technology, develop potential urine biomarkers of treatment success. 1R21 CA178324-01A1 (Kraft, PI) 06/01/15

Diffraction-based BioCD biosensor for point-of-care diagnostics

NASA Astrophysics Data System (ADS)

Choi, H.; Chang, C.; Savran, C.; Nolte, D.

2018-02-01

The BioCD platform technology uses spinning-disk interferometry to detect molecular binding to target molecular probes in biological samples. Interferometric configurations have included differential phase contrast and in-line quadrature detection. For the detection of extremely low analyte concentrations, nano- or microparticles can enhance the signal through background-free diffraction detection. Diffraction signal measurements on BioCD biosensors are achieved by forming gratings on a disc surface. The grating pattern was printed with biotinylated bovine serum albumin (BSA) and streptavidin coated beads were deployed. The diameter of the beads was 1 micron and strong protein bonding occurs between BSA and streptavidin-coated beads at the printed location. The wavelength for the protein binding detection was 635 nm. The periodic pattern on the disc amplified scattered light into the first-order diffraction position. The diffracted signal contains Mie scattering and a randomly-distributed-bead noise contributions. Variation of the grating pattern periodicity modulates the diffraction efficiency. To test multiple spatial frequencies within a single scan, we designed a fan-shaped grating to perform frequency filter multiplexing on a diffraction-based BioCD.

Breath-Taking Patterns: Discontinuous Hydrophilic Regions for Photonic Crystal Beads Assembly and Patterns Revisualization.

PubMed

Du, Xuemin; Wang, Juan; Cui, Huanqing; Zhao, Qilong; Chen, Hongxu; He, Le; Wang, Yunlong

2017-11-01

Surfaces patterned with hydrophilic and hydrophobic regions provide robust and versatile means for investigating the wetting behaviors of liquids, surface properties analysis, and producing patterned arrays. However, the fabrication of integral and uniform arrays onto these open systems remains a challenge, thus restricting them from being used in practical applications. Here, we present a simple yet powerful approach for the fabrication of water droplet arrays and the assembly of photonic crystal bead arrays based on hydrophilic-hydrophobic patterned substrates. Various integral arrays are simply prepared in a high-quality output with a low cost, large scale, and uniform size control. By simply taking a breath, which brings moisture to the substrate surface, complex hydrophilic-hydrophobic outlined images can be revisualized in the discontinuous hydrophilic regions. Integration of hydrogel photonic crystal bead arrays into the "breath-taking" process results in breath-responsive photonic crystal beads, which can change their colors upon a mild exhalation. This state-of-the-art technology not only provides an effective methodology for the preparation of patterned arrays but also demonstrates intriguing applications in information storage and biochemical sensors.

Capture-SELEX: Selection of DNA Aptamers for Aminoglycoside Antibiotics

PubMed Central

2012-01-01

Small organic molecules are challenging targets for an aptamer selection using the SELEX technology (SELEX—Systematic Evolution of Ligans by EXponential enrichment). Often they are not suitable for immobilization on solid surfaces, which is a common procedure in known aptamer selection methods. The Capture-SELEX procedure allows the selection of DNA aptamers for solute targets. A special SELEX library was constructed with the aim to immobilize this library on magnetic beads or other surfaces. For this purpose a docking sequence was incorporated into the random region of the library enabling hybridization to a complementary oligo fixed on magnetic beads. Oligonucleotides of the library which exhibit high affinity to the target and a secondary structure fitting to the target are released from the beads for binding to the target during the aptamer selection process. The oligonucleotides of these binding complexes were amplified, purified, and immobilized via the docking sequence to the magnetic beads as the starting point of the following selection round. Based on this Capture-SELEX procedure, the successful DNA aptamer selection for the aminoglycoside antibiotic kanamycin A as a small molecule target is described. PMID:23326761

Method To immobilize the aphid-pathogenic fungus erynia neoaphidis in an alginate matrix for biocontrol

PubMed

Shah; Aebi; Tuor

1998-11-01

Erynia neoaphidis is an important fungal pathogen of aphid pests worldwide. There have been few reported attempts to formulate this natural agent for use in biocontrol. In the current study, factors involved in the immobilization of E. neoaphidis hyphae in an alginate matrix were investigated. Hyphae of two isolates cultured in liquid medium were 220 to 620 &mgr;m in length and 7 to 19 &mgr;m in diameter with a 74 to 83% cytoplasmic content. The optimal concentration of low-viscosity sodium alginate for production of conidia from entrapped hyphae was 1.5% (wt/vol), and 0.1 and 0.25 M calcium chloride were equally suitable for use as the gelling solution. Alginate beads were rinsed with 10% sucrose after gelling. However, beads should not be left for longer than 40 min in 0.1 M calcium chloride or 10% sucrose to prevent a 10% loss in conidial production. A 40% (vol/vol) concentration of fungal biomass produced significantly more conidia than either 20% or the standard concentration of 10%. This effect persisted even after beads were dried overnight in a laminar flow hood and stored at 4 degreesC for 4 days. Conidia from freshly produced alginate beads caused 27 to 32% infection in Pea aphids as determined by standardized laboratory bioassays. This finding was not significantly different from infections in aphids inoculated with fresh mycelial mats or plugs from Petri dish cultures. In conclusion, algination appears to be a promising technique for utilizing E. neoaphidis in the biocontrol of aphid pests.

Quantum-dot-tagged microbeads for multiplexed optical coding of biomolecules.

PubMed

Han, M; Gao, X; Su, J Z; Nie, S

2001-07-01

Multicolor optical coding for biological assays has been achieved by embedding different-sized quantum dots (zinc sulfide-capped cadmium selenide nanocrystals) into polymeric microbeads at precisely controlled ratios. Their novel optical properties (e.g., size-tunable emission and simultaneous excitation) render these highly luminescent quantum dots (QDs) ideal fluorophores for wavelength-and-intensity multiplexing. The use of 10 intensity levels and 6 colors could theoretically code one million nucleic acid or protein sequences. Imaging and spectroscopic measurements indicate that the QD-tagged beads are highly uniform and reproducible, yielding bead identification accuracies as high as 99.99% under favorable conditions. DNA hybridization studies demonstrate that the coding and target signals can be simultaneously read at the single-bead level. This spectral coding technology is expected to open new opportunities in gene expression studies, high-throughput screening, and medical diagnostics.

Direct binding to antigen-coated beads refines the specificity and cross-reactivity of four monoclonal antibodies that recognize polymorphic epitopes of HLA class I molecules

PubMed Central

Hilton, Hugo G; Parham, Peter

2013-01-01

Monoclonal antibodies with specificity for HLA class I determinants of HLA were originally characterized using serological assays in which the targets were cells expressing 3-6 HLA class I variants. Because of this complexity, the specificities of the antibodies were defined indirectly by correlation. Here we use a direct binding assay, in which the targets are synthetic beads coated with one of 111 HLA class I variants, representing the full range of HLA-A, -B and -C variation. We studied one monoclonal antibody with monomorphic specificity (W6/32) and four with polymorphic specificity (MA2.1, PA2.1, BB7.2 and BB7.1) and compared the results with those obtained previously. W6/32 reacted with all HLA class I variants. MA2.1 exhibits high specificity for HLA-A*02, -B*57 and -B*58, but also exhibited cross-reactivity with HLA-A*11 and -B*15:16. At low concentration (1μg/ml) PA2.1 and BB7.2 were both specific for HLA-A*02 and -A*69, and at high concentration (50μg/ml) exhibited significant cross-reactions with HLA-A*68, -A*23, and -A*24. BB7.1 exhibits specificity for HLA-B*07 and -B*42, as previously described, but reacts equally well with HLA-B*81, a rare allotype defined some 16 years after the description of BB7.1. The results obtained with cell-based and bead-based assays are consistent and, in combination with amino acid sequence comparison, increase understanding of the polymorphic epitopes recognized by the MA2.1, PA2.1, BB7.2 and BB7.1 antibodies. Comparison of two overlapping but distinctive bead sets from two sources gave similar results, but the overall levels of binding were significantly different. Several weaker reactions were observed with only one of the bead sets. PMID:23510417

Frictionless bead packs have macroscopic friction, but no dilatancy.

PubMed

Peyneau, Pierre-Emmanuel; Roux, Jean-Noël

2008-07-01

The statement of the title is shown by numerical simulation of homogeneously sheared assemblies of frictionless, nearly rigid beads in the quasistatic limit. Results coincide for steady flows at constant shear rate gamma[over ] in the limit of small gamma[over ] and static approaches, in which packings are equilibrated under growing deviator stresses. The internal friction angle phi , equal to 5.76 degrees +/-0.22 degrees in simple shear, is independent of average pressure P in the rigid limit and stems from the ability of stable frictionless contact networks to form stress-induced anisotropic fabrics. No enduring strain localization is observed. Dissipation at the macroscopic level results from repeated network rearrangements, similar to the effective friction of a frictionless slider on a bumpy surface. Solid fraction Phi remains equal to the random close packing value approximately 0.64 in slowly or statically sheared systems. Fluctuations of stresses and volume are observed to regress in the large system limit. Defining the inertial number as I=gamma radical m/(aP), with m the grain mass and a its diameter, both internal friction coefficient mu*=tan phi and volume 1/Phi increase as powers of I in the quasistatic limit of vanishing I , in which all mechanical properties are determined by contact network geometry. The microstructure of the sheared material is characterized with a suitable parametrization of the fabric tensor and measurements of coordination numbers.

3D-Laser-Scanning Technique Applied to Bulk Density Measurements of Apollo Lunar Samples

NASA Technical Reports Server (NTRS)

Macke, R. J.; Kent, J. J.; Kiefer, W. S.; Britt, D. T.

2015-01-01

In order to better interpret gravimetric data from orbiters such as GRAIL and LRO to understand the subsurface composition and structure of the lunar crust, it is import to have a reliable database of the density and porosity of lunar materials. To this end, we have been surveying these physical properties in both lunar meteorites and Apollo lunar samples. To measure porosity, both grain density and bulk density are required. For bulk density, our group has historically utilized sub-mm bead immersion techniques extensively, though several factors have made this technique problematic for our work with Apollo samples. Samples allocated for measurement are often smaller than optimal for the technique, leading to large error bars. Also, for some samples we were required to use pure alumina beads instead of our usual glass beads. The alumina beads were subject to undesirable static effects, producing unreliable results. Other investigators have tested the use of 3d laser scanners on meteorites for measuring bulk volumes. Early work, though promising, was plagued with difficulties including poor response on dark or reflective surfaces, difficulty reproducing sharp edges, and large processing time for producing shape models. Due to progress in technology, however, laser scanners have improved considerably in recent years. We tested this technique on 27 lunar samples in the Apollo collection using a scanner at NASA Johnson Space Center. We found it to be reliable and more precise than beads, with the added benefit that it involves no direct contact with the sample, enabling the study of particularly friable samples for which bead immersion is not possible

Fabrication of magnetic alginate beads with uniform dispersion of CoFe2O4 by the polydopamine surface functionalization for organic pollutants removal

NASA Astrophysics Data System (ADS)

Li, Xiaoli; Lu, Haijun; Zhang, Yun; He, Fu; Jing, Lingyun; He, Xinghua

2016-12-01

A simple and efficient method for production of magnetic composites by decorating CoFe2O4 with polydopamine (PDA) through oxidative polymerization of dopamine was conducted. Further, magnetic alginate beads with porous structure containing well-dispersed CoFe2O4-PDA were fabricated by ionic crosslinking technology. The resulting SA@CoFe2O4-PDA beads were characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Adsorption potential of SA@CoFe2O4-PDA beads for organic dyes including Methylene Blue (MB), Crystal Violet (CV) and Malachite Green (MG) was evaluated. SA@CoFe2O4-PDA beads exhibited excellent adsorption performances due to the composite effect, large surface area and porous structure. Organic dyes could be removed from water solution with high efficiency in a wide pH range of 4.0-9.0. Moreover, it exhibited much higher adsorptivity towards MB and CV with the maximum adsorption capacities of 466.60 and 456.52 mg/g, respectively, which were much higher than that of MG (248.78 mg/g). Ca-electrolyte had obvious adverse effects on MB and CV adsorption than MG. FTIR and XPS demonstrated that carboxylate, catechol, hydroxyl and amine groups might be involved in adsorption of organic dyes. The characteristics of wide pH range, high adsorption capacity and convenient magnetic separation would make SA@CoFe2O4-PDA beads as effective adsorbent for removal of organic dyes from wastewater.

Quantitative screening of yeast surface-displayed polypeptide libraries by magnetic bead capture.

PubMed

Yeung, Yik A; Wittrup, K Dane

2002-01-01

Magnetic bead capture is demonstrated here to be a feasible alternative for quantitative screening of favorable mutants from a cell-displayed polypeptide library. Flow cytometric sorting with fluorescent probes has been employed previously for high throughput screening for either novel binders or improved mutants. However, many laboratories do not have ready access to this technology as a result of the limited availability and high cost of cytometers, restricting the use of cell-displayed libraries. Using streptavidin-coated magnetic beads and biotinylated ligands, an alternative approach to cell-based library screening for improved mutants was developed. Magnetic bead capture probability of labeled cells is shown to be closely correlated with the surface ligand density. A single-pass enrichment ratio of 9400 +/- 1800-fold, at the expense of 85 +/- 6% binder losses, is achieved from screening a library that contains one antibody-displaying cell (binder) in 1.1 x 10(5) nondisplaying cells. Additionally, kinetic screening for an initial high affinity to low affinity (7.7-fold lower) mutant ratio of 1:95,000, the magnetic bead capture method attains a single-pass enrichment ratio of 600 +/- 200-fold with a 75 +/- 24% probability of loss for the higher affinity mutant. The observed high loss probabilities can be straightforwardly compensated for by library oversampling, given the inherently parallel nature of the screen. Overall, these results demonstrate that magnetic beads are capable of quantitatively screening for novel binders and improved mutants. The described methods are directly analogous to procedures in common use for phage display and should lower the barriers to entry for use of cell surface display libraries.

Bioaugmented remediation of high concentration BTEX-contaminated groundwater by permeable reactive barrier with immobilized bead.

PubMed

Xin, Bao-Ping; Wu, Chih-Hung; Wu, Cheng-Han; Lin, Chi-Wen

2013-01-15

Ineffective biostimulation requires immediate development of new technologies for remediation of high concentration BTEX-contaminated (benzene, toluene, ethylbenzene and xylene) groundwater. In this study, bioaugmentation with Mycobacterium sp. CHXY119 and Pseudomonas sp. YATO411 immobilized bead was used to remediate BTEX-contaminated groundwater with about 100 mg l(-1) in total concentration. The batch test results showed that the CHXY119 and YATO411 immobilized bead completely biodegraded each BTEX compound, and the maximum biodegradation rates were 0.790 mg l(-1) h(-1) for benzene, 1.113 mg l(-1) h(-1) for toluene, 0.992 mg l(-1) h(-1) for ethylbenzene and 0.231 mg l(-1) h(-1) for p-xylene. The actual mineralization rates were 10.8% for benzene, 10.5% for toluene, 5.8% for ethylbenzene and 11.4% for p-xylene, which indicated that the bioremediation of BTEX by the immobilized bead requires a rather small oxygen supply. Degradation rates achieved by the bioaugmented permeable reactive barrier (Bio-PRB) system of the immobilized bead were 97.8% for benzene, 94.2% for toluene, 84.7% for ethylbenzene and 87.4% for p-xylene; and the toxicity of the groundwater fell by 91.2% after bioremediation by the bioaugmented PRB, which confirmed its great potential for remediating groundwater with high concentrations of contaminants. Copyright © 2012 Elsevier B.V. All rights reserved.

Gel Fabrication of Molybdenum “Beads”

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowden, Richard Andrew; Armstrong, Beth L.; Cooley, Kevin M.

2016-11-01

Spherical molybdenum particles or “beads” of various diameters are of interest as feedstock materials for the additive manufacture of targets and assemblies used in the production of 99Mo medical isotopes using accelerator technology. Small metallic beads or ball bearings are typically fabricated from wire; however, small molybdenum spheres cannot readily be produced in this manner. Sol-gel processes are often employed to produce small dense microspheres of metal oxides across a broad diameter range that in the case of molybdenum could be reduced and sintered to produce metallic spheres. These Sol-gel type processes were examined for forming molybdenum oxide beads; however,more » the molybdenum trioxide was chemically incompatible with commonly used gelation materials. As an alternative, an aqueous alginate process being assessed for the fabrication of oxide spheres for catalyst applications was employed to form molybdenum trioxide beads that were successfully reduced and sintered to produce small molybdenum spheres.« less

Affinity adsorption of glucose degradation products improves the biocompatibility of conventional peritoneal dialysis fluid.

PubMed

Ishikawa, Naoyoshi; Miyata, Toshio; Ueda, Yasuhiko; Inagi, Reiko; Izuhara, Yuko; Yuzawa, Hiroko; Onogi, Hiroshi; Nishina, Makoto; Nangaku, Masaomi; Van Ypersele De Strihou, Charles; Kurokawa, Kiyoshi

2003-01-01

Reactive carbonyl compounds (RCOs) present in peritoneal dialysis (PD) fluid have been incriminated in the progressive deterioration of the peritoneal membrane in long-term PD patients. They are initially present in fresh conventional heat-sterilized glucose PD fluid and are supplemented during dwell time by the diffusion of blood RCOs within the peritoneal cavity. In the present study, RCO entrapping agents were immobilized on affinity beads to adsorb RCOs both in fresh PD fluid and in PD effluent. The RCO trapping potential of various compounds was assessed in vitro first by dissolving them in the tested fluid and subsequently after coupling with either epoxy- or amino-beads. The tested fluids include fresh heat-sterilized glucose and non-glucose PD fluids, and PD effluent. Their RCOs contents, that is, glyoxal (GO), methylglyoxal (MGO), 3-deoxyglucosone (3-DG), formaldehyde, 5-hydroxymethylfuraldehyde, acetaldehyde, and 2-furaldehyde were monitored by reverse-phase high-pressure liquid chromatography. The biocompatibility of PD fluid was assessed by a cytotoxic assay with either human epidermoid cell line A431 cells or with primary cultured human peritoneal mesothelial cells. Among the tested RCO entrapping agents, hydrazine coupled to epoxy-beads proved the most efficient. It lowered the concentrations of three dicarbonyl compounds (GO, MGO, and 3-DG) and those of aldehydes present in fresh heat-sterilized glucose PD fluid toward the low levels observed in filter-sterilized glucose PD fluid. It did not change the glucose and electrolytes concentration of the PD fluid but raised its pH from 5.2 to 5.9. Hydrazine-coupled epoxy-bead also lowered the PD effluent content of total RCOs, measured by the 2,4-dinitrophenylhydrazone (DNPH) method. The cytotoxicity of heat-sterilized PD fluid incubated with hydrazine-coupled epoxy-beads was decreased to the level observed in filter-sterilized PD fluid as the result of the raised pH and the lowered RCOs levels. Hydrazine-coupled epoxy-beads reduce the levels of a variety of dicarbonyls and aldehydes present in heat-sterilized glucose PD fluid to those in filter-sterilized PD fluid, without altering glucose, lactate, and electrolytes contents but with a rise in pH. Incubated with PD effluents, it is equally effective in reducing the levels of serum-derived RCOs. RCO entrapping agents immobilized on affinity beads improve in vitro the biocompatibility of conventional heat-sterilized glucose PD fluid. Their clinical applicability requires further studies.

Heat transfer studies. Quarterly report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boehm, R.; Chen, Y.; Izzeldin, A.

The experiments on determination of the wavelength corresponding to the equality of the refractive indices and how this varies with temperature have been completed. This was accomplished using the calibration setup of a 2-inch-long test cell filled with 2 mm diameter soda-lime glass beads. Some good images result, but these are not very clear. Therefore, a 1-inch long test cell has now been built. The modified test cell is shown. A 30-gauge type K thermocouple is placed at the center inside the test cell. A model 450 AET Omega thermocouple thermometer is used to indicate the temperature from the thermocouple.more » A polyurethane foam insulator covered the test cell circular wall to approximate an adiabatic condition. The organic chemical liquid and glass beads are heated up by the mica band heater. A variable transformer is used to the control power to the heater and, thus, the temperature in the cell. The temperature is slowly increased from ambient to try to maintain a generally homogeneous temperature inside the cell. If the indices of refraction of the glass beads and the organic liquid are the same, the image of glass beads then can be found. Chlorobenzene (C{sub 6}H{sub 5}Cl) with a refractive index of about 1.52 at 25{degrees}C (boiling point of 131.6{degrees}C), has been used as the organic chemical liquid. A 5 W argon-ion laser has been used as the light source to visualize the image generated by the Christiansen effect. Two optical grade prisms are used to separate the three wavelengths (green, teal, and blue) of the beam. 80 {mu}m and 200 {mu}m apertures are used to select a single wavelength portion of the beam (either 488 nm blue or 514.5 nm green).« less

Enhancing gas-liquid mass transfer rates in non-newtonian fermentations by confining mycelial growth to microbeads in a bubble column

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gbewonyo, K.; Wang, D.I.C.

The performance of a penicillin fermentation was assessed in a laboratory-scale bubble column fermentor, with mycelial growth confined to the pore matrix of celite beads. Final cell densities of 29 g/L and penicillin titres of 5.5 g/L were obtained in the confined cell cultures. In comparison, cultures of free mycelial cells grown in the absence of beads experienced dissolved oxygen limitations in the bubble column, giving only 17 g/L final cell concentrations with equally low penicillin titres of 2 g/L. The better performance of the confined cell cultures was attributed to enhanced gas liquid mass transfer rates, with mass transfermore » coefficients (k /SUB L/ a) two to three times higher than those determined in the free cell cultures. Furthermore, the confined cell cultures showed more efficient utilization of power input for mass transfer, providing up to 50% reduction in energy requirements for aeration.« less

Electrochemical Detection of E. coli O157:H7 in Water after Electrocatalytic and Ultraviolet Treatments Using a Polyguanine-Labeled Secondary Bead Sensor.

PubMed

Beeman, Michael G; Nze, Ugochukwu C; Sant, Himanshu J; Malik, Hammad; Mohanty, Swomitra; Gale, Bruce K; Carlson, Krista

2018-05-10

The availability of clean drinking water is a significant problem worldwide. Many technologies exist for purifying drinking water, however, many of these methods require chemicals or use simple methods, such as boiling and filtering, which may or may not be effective in removing waterborne pathogens. Present methods for detecting pathogens in point-of-use (POU) sterilized water are typically time prohibitive or have limited ability differentiating between active and inactive cells. This work describes a rapid electrochemical sensor to differentially detect the presence of active Escherichia coli (E. coli) O157:H7 in samples that have been partially or completely sterilized using a new POU electrocatalytic water purification technology based on superradicals generated by defect laden titania (TiO₂) nanotubes. The sensor was also used to detect pathogens sterilized by UV-C radiation for a comparison of different modes of cell death. The sensor utilizes immunomagnetic bead separation to isolate active bacteria by forming a sandwich assay comprised of antibody functionalized secondary magnetic beads, E. coli O157:H7, and polyguanine (polyG) oligonucleotide functionalized secondary polystyrene beads as an electrochemical tag. The assay is formed by the attachment of antibodies to active receptors on the membrane of E. coli , allowing the sensor to differentially detect viable cells. Ultravioloet (UV)-C radiation and an electrocatalytic reactor (ER) with integrated defect-laden titania nanotubes were used to examine the sensors’ performance in detecting sterilized cells under different modes of cell death. Plate counts and flow cytometry were used to quantify disinfection efficacy and cell damage. It was found that the ER treatments shredded the bacteria into multiple fragments, while UV-C treatments inactivated the bacteria but left the cell membrane mostly intact.

Early upper paleolithic shell beads at Üçağızlı Cave I (Turkey): technology and the socioeconomic context of ornament life-histories.

PubMed

Stiner, Mary C; Kuhn, Steven L; Güleç, Erksin

2013-05-01

Ten early Upper Paleolithic layers in Üçağızlı Cave I (41-29 uncalibrated ky BP) on the Hatay coast of southern Turkey preserve a rich and varied record of early Upper Paleolithic life, including the production and use of large numbers of shell ornaments. This study examines shell bead production, use, and discard in relation to site function and the diversity of on-site human activities. Four factors are expected to contribute to variation in the ornament assemblages, one environmental and three behavioral. The behavioral factors relate to winnowing for quality as a function of distance from the raw material source, changes in the size of user groups, and symbol standardization. The accumulation rates for shell beads, bones, and stone tools paralleled one another through time, indicating that ornament discard followed the pulse of daily life at this site. All stages of manufacture and use are well represented in each assemblage, and half or more of the ornaments show evidence of extended use. Changes in the local marine environment do not explain much of the variation in the assemblages, pointing instead to behavioral causes. The richness of shell types that were collected as raw material correlates to greater exploitation of edible marine shellfish and greater occupation intensity. Much of this variation in the ornament raw material was eliminated during the manufacture stage, almost certainly reflecting the influence of cultural norms. A focus on basket-shaped shells changed remarkably little over thousands of years, despite significant changes in other domains of technology. This last result suggests that beads were the most irreducible and conservative elements of more complex design traditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Detection of Neisseria meningitidis in cerebrospinal fluid using a multiplex PCR and the Luminex detection technology.

PubMed

Møller, Jens Kjølseth

2012-01-01

Rapid clinical and laboratory diagnoses are the foundation for a successful management of serious infections with Neisseria meningitidis. A species-specific multiplex polymerase chain reaction (PCR) coupled with fluidic microarrays using microbeads (the Luminex xMAP™ Technology) can detect pathogens most frequently found in the cerebrospinal fluid of patients. The Luminex suspension array system uniquely combines flow cytometry, microspheres, laser technology, digital signal processing, and traditional chemistry. In this method, the reaction is carried out in one vessel, in which distinctly color-coded bead sets, each conjugated with a different specific nucleic acid reactant, are hybridized with the PCR products, and a reporter molecule is used to quantify the interaction. The flow-based Luminex array reader identifies each reaction (bead set) after excitation by a red classification laser. Reporter signals from each reaction are simultaneously quantified by fluorescence generated by a green reporter laser. This nonculture, multiplex assay may prove to be an important tool for optimal laboratory diagnosis, not only of meningococcal meningitis, but also of meningitis caused by other bacterial or viral pathogens.

Porous cobalt spheres for high temperature gradient magnetically assisted fluidized beds

NASA Technical Reports Server (NTRS)

Atwater, James E.; Akse, James R.; Jovanovic, Goran N.; Wheeler, Richard R Jr; Sornchamni, Thana

2003-01-01

Porous metallic cobalt spheres have been prepared as high temperature capable media for employment in gradient magnetically assisted fluidization and filtration technologies. Cobalt impregnated alginate beads are first formed by extrusion of an aqueous suspension of Co3O4 into a Co(II) chloride solution. The organic polymer is thermally decomposed yielding cobalt oxide spheres, followed by reduction to the metallic state, and densification. Cobalt beads have been produced with porosities ranging between 10 and 50%, depending upon sintering conditions. The product media have been characterized by scanning electron microscopy (SEM), nitrogen adsorption porosimetry, and vibrating sample magnetometry. c2003 Elsevier Science Ltd. All rights reserved.

Direct binding to antigen-coated beads refines the specificity and cross-reactivity of four monoclonal antibodies that recognize polymorphic epitopes of HLA class I molecules.

PubMed

Hilton, H G; Parham, P

2013-04-01

Monoclonal antibodies with specificity for human leukocyte antigen (HLA) class I determinants of HLA were originally characterized using serological assays in which the targets were cells expressing three to six HLA class I variants. Because of this complexity, the specificities of the antibodies were defined indirectly by correlation. Here we use a direct binding assay, in which the targets are synthetic beads coated with 1 of 111 HLA class I variants, representing the full range of HLA-A, -B and -C variation. We studied one monoclonal antibody with monomorphic specificity (W6/32) and four with polymorphic specificity (MA2.1, PA2.1, BB7.2 and BB7.1) and compared the results with those obtained previously. W6/32 reacted with all HLA class I variants. MA2.1 not only exhibits high specificity for HLA-A*02, -B*57 and -B*58, but also exhibited cross-reactivity with HLA-A*11 and -B*15:16. At low concentration (1 µg/ml), PA2.1 and BB7.2 were both specific for HLA-A*02 and -A*69, and at high concentration (50 µg/ml) exhibited significant cross-reactions with HLA-A*68, -A*23 and -A*24. BB7.1 exhibits specificity for HLA-B*07 and -B*42, as previously described, but reacts equally well with HLA-B*81, a rare allotype defined some 16 years after the description of BB7.1. The results obtained with cell-based and bead-based assays are consistent and, in combination with amino acid sequence comparison, increase understanding of the polymorphic epitopes recognized by the MA2.1, PA2.1, BB7.2 and BB7.1 antibodies. Comparison of two overlapping but distinctive bead sets from two sources gave similar results, but the overall levels of binding were significantly different. Several weaker reactions were observed with only one of the bead sets. © 2013 John Wiley & Sons A/S.

Direct Identification of On-Bead Peptides Using Surface-Enhanced Raman Spectroscopic Barcoding System for High-Throughput Bioanalysis

PubMed Central

Kang, Homan; Jeong, Sinyoung; Koh, Yul; Geun Cha, Myeong; Yang, Jin-Kyoung; Kyeong, San; Kim, Jaehi; Kwak, Seon-Yeong; Chang, Hye-Jin; Lee, Hyunmi; Jeong, Cheolhwan; Kim, Jong-Ho; Jun, Bong-Hyun; Kim, Yong-Kweon; Hong Jeong, Dae; Lee, Yoon-Sik

2015-01-01

Recently, preparation and screening of compound libraries remain one of the most challenging tasks in drug discovery, biomarker detection, and biomolecular profiling processes. So far, several distinct encoding/decoding methods such as chemical encoding, graphical encoding, and optical encoding have been reported to identify those libraries. In this paper, a simple and efficient surface-enhanced Raman spectroscopic (SERS) barcoding method using highly sensitive SERS nanoparticles (SERS ID) is presented. The 44 kinds of SERS IDs were able to generate simple codes and could possibly generate more than one million kinds of codes by incorporating combinations of different SERS IDs. The barcoding method exhibited high stability and reliability under bioassay conditions. The SERS ID encoding based screening platform can identify the peptide ligand on the bead and also quantify its binding affinity for specific protein. We believe that our SERS barcoding technology is a promising method in the screening of one-bead-one-compound (OBOC) libraries for drug discovery. PMID:26017924

Direct identification of on-bead peptides using surface-enhanced Raman spectroscopic barcoding system for high-throughput bioanalysis.

PubMed

Kang, Homan; Jeong, Sinyoung; Koh, Yul; Geun Cha, Myeong; Yang, Jin-Kyoung; Kyeong, San; Kim, Jaehi; Kwak, Seon-Yeong; Chang, Hye-Jin; Lee, Hyunmi; Jeong, Cheolhwan; Kim, Jong-Ho; Jun, Bong-Hyun; Kim, Yong-Kweon; Hong Jeong, Dae; Lee, Yoon-Sik

2015-05-28

Recently, preparation and screening of compound libraries remain one of the most challenging tasks in drug discovery, biomarker detection, and biomolecular profiling processes. So far, several distinct encoding/decoding methods such as chemical encoding, graphical encoding, and optical encoding have been reported to identify those libraries. In this paper, a simple and efficient surface-enhanced Raman spectroscopic (SERS) barcoding method using highly sensitive SERS nanoparticles (SERS ID) is presented. The 44 kinds of SERS IDs were able to generate simple codes and could possibly generate more than one million kinds of codes by incorporating combinations of different SERS IDs. The barcoding method exhibited high stability and reliability under bioassay conditions. The SERS ID encoding based screening platform can identify the peptide ligand on the bead and also quantify its binding affinity for specific protein. We believe that our SERS barcoding technology is a promising method in the screening of one-bead-one-compound (OBOC) libraries for drug discovery.

Development of a Scintillation Proximity Assay (SPA) Based, High Throughput Screening Feasible Method for the Identification of PDE12 Activity Modulators.

PubMed

Mang, Samuel; Bucher, Hannes; Nickolaus, Peter

2016-01-01

The scintillation proximity assay (SPA) technology has been widely used to establish high throughput screens (HTS) for a range of targets in the pharmaceutical industry. PDE12 (aka. 2'- phosphodiesterase) has been published to participate in the degradation of oligoadenylates that are involved in the establishment of an antiviral state via the activation of ribonuclease L (RNAse-L). Degradation of oligoadenylates by PDE12 terminates these antiviral activities, leading to decreased resistance of cells for a variety of viral pathogens. Therefore inhibitors of PDE12 are discussed as antiviral therapy. Here we describe the use of the yttrium silicate SPA bead technology to assess inhibitory activity of compounds against PDE12 in a homogeneous, robust HTS feasible assay using tritiated adenosine-P-adenylate ([3H]ApA) as substrate. We found that the used [3H]ApA educt, was not able to bind to SPA beads, whereas the product [3H]AMP, as known before, was able to bind to SPA beads. This enables the measurement of PDE12 activity on [3H]ApA as a substrate using a wallac microbeta counter. This method describes a robust and high throughput capable format in terms of specificity, commonly used compound solvents, ease of detection and assay matrices. The method could facilitate the search for PDE12 inhibitors as antiviral compounds.

Middle and Later Stone Age chronology of Kisese II rockshelter (UNESCO World Heritage Kondoa Rock-Art Sites), Tanzania.

PubMed

Tryon, Christian A; Lewis, Jason E; Ranhorn, Kathryn L; Kwekason, Amandus; Alex, Bridget; Laird, Myra F; Marean, Curtis W; Niespolo, Elizabeth; Nivens, Joelle; Mabulla, Audax Z P

2018-01-01

The archaeology of East Africa during the last ~65,000 years plays a central role in debates about the origins and dispersal of modern humans, Homo sapiens. Despite the historical importance of the region to these discussions, reliable chronologies for the nature, tempo, and timing of human behavioral changes seen among Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological assemblages are sparse. The Kisese II rockshelter in the Kondoa region of Tanzania, originally excavated in 1956, preserves a ≥ 6-m-thick archaeological succession that spans the MSA/LSA transition, with lithic artifacts such as Levallois and bladelet cores and backed microliths, the recurrent use of red ochre, and >5,000 ostrich eggshell beads and bead fragments. Twenty-nine radiocarbon dates on ostrich eggshell carbonate make Kisese II one of the most robust chronological sequences for understanding archaeological change over the last ~47,000 years in East Africa. In particular, ostrich eggshell beads and backed microliths appear by 46-42 ka cal BP and occur throughout overlying Late Pleistocene and Holocene strata. Changes in lithic technology suggest an MSA/LSA transition that began 39-34.3 ka, with typical LSA technologies in place by the Last Glacial Maximum. The timing of these changes demonstrates the time-transgressive nature of behavioral innovations often linked to the origins of modern humans, even within a single region of Africa.

Effects of Droplet Size on Intrusion of Sub-Surface Oil Spills

NASA Astrophysics Data System (ADS)

Adams, Eric; Chan, Godine; Wang, Dayang

2014-11-01

We explore effects of droplet size on droplet intrusion and transport in sub-surface oil spills. Negatively buoyant glass beads released continuously to a stratified ambient simulate oil droplets in a rising multiphase plume, and distributions of settled beads are used to infer signatures of surfacing oil. Initial tests used quiescent conditions, while ongoing tests simulate currents by towing the source and a bottom sled. Without current, deposited beads have a Gaussian distribution, with variance increasing with decreasing particle size. Distributions agree with a model assuming first order particle loss from an intrusion layer of constant thickness, and empirically determined flow rate. With current, deposited beads display a parabolic distribution similar to that expected from a source in uniform flow; we are currently comparing observed distributions with similar analytical models. Because chemical dispersants have been used to reduce oil droplet size, our study provides one measure of their effectiveness. Results are applied to conditions from the `Deep Spill' field experiment, and the recent Deepwater Horizon oil spill, and are being used to provide ``inner boundary conditions'' for subsequent far field modeling of these events. This research was made possible by grants from Chevron Energy Technology Co., through the Chevron-MITEI University Partnership Program, and BP/The Gulf of Mexico Research Initiative, GISR.

A simplified immunoprecipitation method for quantitatively measuring antibody responses in clinical sera samples by using mammalian-produced Renilla luciferase-antigen fusion proteins.

PubMed

Burbelo, Peter D; Goldman, Radoslav; Mattson, Thomas L

2005-08-18

Assays detecting human antigen-specific antibodies are medically useful. However, the usefulness of existing simple immunoassay formats is limited by technical considerations such as sera antibodies to contaminants in insufficiently pure antigen, a problem likely exacerbated when antigen panels are screened to obtain clinically useful data. We developed a novel and simple immunoprecipitation technology for identifying clinical sera containing antigen-specific antibodies and for generating quantitative antibody response profiles. This method is based on fusing protein antigens to an enzyme reporter, Renilla luciferase (Ruc), and expressing these fusions in mammalian cells, where mammalian-specific post-translational modifications can be added. After mixing crude extracts, sera and protein A/G beads together and incubating, during which the Ruc-antigen fusion become immobilized on the A/G beads, antigen-specific antibody is quantitated by washing the beads and adding coelenterazine substrate and measuring light production. We have characterized this technology with sera from patients having three different types of cancers. We show that 20-85% of these sera contain significant titers of antibodies against at least one of five frequently mutated and/or overexpressed tumor-associated proteins. Five of six colon cancer sera tested gave responses that were statistically significantly greater than the average plus three standard deviations of 10 control sera. The results of competition experiments, preincubating positive sera with unmodified E. coli-produced antigens, varied dramatically. This technology has several advantages over current quantitative immunoassays including its relative simplicity, its avoidance of problems associated with E. coli-produced antigens and its use of antigens that can carry mammalian or disease-specific post-translational modifications. This assay should be generally useful for analyzing sera for antibodies recognizing any protein or its post-translational modifications.

A simplified immunoprecipitation method for quantitatively measuring antibody responses in clinical sera samples by using mammalian-produced Renilla luciferase-antigen fusion proteins

PubMed Central

Burbelo, Peter D; Goldman, Radoslav; Mattson, Thomas L

2005-01-01

Background Assays detecting human antigen-specific antibodies are medically useful. However, the usefulness of existing simple immunoassay formats is limited by technical considerations such as sera antibodies to contaminants in insufficiently pure antigen, a problem likely exacerbated when antigen panels are screened to obtain clinically useful data. Results We developed a novel and simple immunoprecipitation technology for identifying clinical sera containing antigen-specific antibodies and for generating quantitative antibody response profiles. This method is based on fusing protein antigens to an enzyme reporter, Renilla luciferase (Ruc), and expressing these fusions in mammalian cells, where mammalian-specific post-translational modifications can be added. After mixing crude extracts, sera and protein A/G beads together and incubating, during which the Ruc-antigen fusion become immobilized on the A/G beads, antigen-specific antibody is quantitated by washing the beads and adding coelenterazine substrate and measuring light production. We have characterized this technology with sera from patients having three different types of cancers. We show that 20–85% of these sera contain significant titers of antibodies against at least one of five frequently mutated and/or overexpressed tumor-associated proteins. Five of six colon cancer sera tested gave responses that were statistically significantly greater than the average plus three standard deviations of 10 control sera. The results of competition experiments, preincubating positive sera with unmodified E. coli-produced antigens, varied dramatically. Conclusion This technology has several advantages over current quantitative immunoassays including its relative simplicity, its avoidance of problems associated with E. coli-produced antigens and its use of antigens that can carry mammalian or disease-specific post-translational modifications. This assay should be generally useful for analyzing sera for antibodies recognizing any protein or its post-translational modifications. PMID:16109166

Evaluation of Time-Temperature Integrators (TTIs) with Microorganism-Entrapped Microbeads Produced Using Homogenization and SPG Membrane Emulsification Techniques.

PubMed

Rahman, A T M Mijanur; Lee, Seung Ju; Jung, Seung Won

2015-12-28

A comparative study was conducted to evaluate precision and accuracy in controlling the temperature dependence of encapsulated microbial time-temperature integrators (TTIs) developed using two different emulsification techniques. Weissela cibaria CIFP 009 cells, immobilized within 2% Na-alginate gel microbeads using homogenization (5,000, 7,000, and 10,000 rpm) and Shirasu porous glass (SPG) membrane technologies (10 μm), were applied to microbial TTIs. The prepared micobeads were characterized with respect to their size, size distribution, shape and morphology, entrapment efficiency, and bead production yield. Additionally, fermentation process parameters including growth rate were investigated. The TTI responses (changes in pH and titratable acidity (TA)) were evaluated as a function of temperature (20°C, 25°C, and 30°C). In comparison with conventional methods, SPG membrane technology was able not only to produce highly uniform, small-sized beads with the narrowest size distribution, but also the bead production yield was found to be nearly 3.0 to 4.5 times higher. However, among the TTIs produced using the homogenization technique, poor linearity (R(2)) in terms of TA was observed for the 5,000 and 7,000 rpm treatments. Consequently, microbeads produced by the SPG membrane and by homogenization at 10,000 rpm were selected for adjusting the temperature dependence. The Ea values of TTIs containing 0.5, 1.0, and 1.5 g microbeads, prepared by SPG membrane and conventional methods, were estimated to be 86.0, 83.5, and 76.6 kJ/mol, and 85.5, 73.5, and 62.2 kJ/mol, respectively. Therefore, microbial TTIs developed using SPG membrane technology are much more efficient in controlling temperature dependence.

Ornaments of the earliest Upper Paleolithic: New insights from the Levant

PubMed Central

Kuhn, Steven L.; Stiner, Mary C.; Reese, David S.; Güleç, Erksin

2001-01-01

Two sites located on the northern Levantine coast, Üçağızlı Cave (Turkey) and Ksar 'Akil (Lebanon) have yielded numerous marine shell beads in association with early Upper Paleolithic stone tools. Accelerator mass spectrometry (AMS) radiocarbon dates indicate ages between 39,000 and 41,000 radiocarbon years (roughly 41,000–43,000 calendar years) for the oldest ornament-bearing levels in Üçağızlı Cave. Based on stratigraphic evidence, the earliest shell beads from Ksar 'Akil may be even older. These artifacts provide some of the earliest evidence for traditions of personal ornament manufacture by Upper Paleolithic humans in western Asia, comparable in age to similar objects from Eastern Europe and Africa. The new data show that the initial appearance of Upper Paleolithic ornament technologies was essentially simultaneous on three continents. The early appearance and proliferation of ornament technologies appears to have been contingent on variable demographic or social conditions. PMID:11390976

A Novel Inherently Radiopaque Bead for Transarterial Embolization to Treat Liver Cancer - A Pre-clinical Study.

PubMed

Duran, Rafael; Sharma, Karun; Dreher, Matthew R; Ashrafi, Koorosh; Mirpour, Sahar; Lin, MingDe; Schernthaner, Ruediger E; Schlachter, Todd R; Tacher, Vania; Lewis, Andrew L; Willis, Sean; den Hartog, Mark; Radaelli, Alessandro; Negussie, Ayele H; Wood, Bradford J; Geschwind, Jean-François H

2016-01-01

Embolotherapy using microshperes is currently performed with soluble contrast to aid in visualization. However, administered payload visibility dimishes soon after delivery due to soluble contrast washout, leaving the radiolucent bead's location unknown. The objective of our study was to characterize inherently radiopaque beads (RO Beads) in terms of physicomechanical properties, deliverability and imaging visibility in a rabbit VX2 liver tumor model. RO Beads, which are based on LC Bead® platform, were compared to LC Bead. Bead size (light microscopy), equilibrium water content (EWC), density, X-ray attenuation and iodine distribution (micro-CT), suspension (settling times), deliverability and in vitro penetration were investigated. Fifteen rabbits were embolized with either LC Bead or RO Beads + soluble contrast (iodixanol-320), or RO Beads+dextrose. Appearance was evaluated with fluoroscopy, X-ray single shot, cone-beam CT (CBCT). Both bead types had a similar size distribution. RO Beads had lower EWC (60-72%) and higher density (1.21-1.36 g/cc) with a homogeneous iodine distribution within the bead's interior. RO Beads suspension time was shorter than LC Bead, with durable suspension (>5 min) in 100% iodixanol. RO Beads ≤300 µm were deliverable through a 2.3-Fr microcatheter. Both bead types showed similar penetration. Soluble contrast could identify target and non-target embolization on fluoroscopy during administration. However, the imaging appearance vanished quickly for LC Bead as contrast washed-out. RO Beads+contrast significantly increased visibility on X-ray single shot compared to LC Bead+contrast in target and non-target arteries (P=0.0043). Similarly, RO beads demonstrated better visibility on CBCT in target arteries (P=0.0238) with a trend in non-target arteries (P=0.0519). RO Beads+dextrose were not sufficiently visible to monitor embolization using fluoroscopy. RO Beads provide better conspicuity to determine target and non-target embolization compared to LC Bead which may improve intra-procedural monitoring and post-procedural evaluation of transarterial embolization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rossi, Mariana; Manolopoulos, David E.; Ceriotti, Michele

Two of the most successful methods that are presently available for simulating the quantum dynamics of condensed phase systems are centroid molecular dynamics (CMD) and ring polymer molecular dynamics (RPMD). Despite their conceptual differences, practical implementations of these methods differ in just two respects: the choice of the Parrinello-Rahman mass matrix and whether or not a thermostat is applied to the internal modes of the ring polymer during the dynamics. Here, we explore a method which is halfway between the two approximations: we keep the path integral bead masses equal to the physical particle masses but attach a Langevin thermostatmore » to the internal modes of the ring polymer during the dynamics. We justify this by showing analytically that the inclusion of an internal mode thermostat does not affect any of the established features of RPMD: thermostatted RPMD is equally valid with respect to everything that has actually been proven about the method as RPMD itself. In particular, because of the choice of bead masses, the resulting method is still optimum in the short-time limit, and the transition state approximation to its reaction rate theory remains closely related to the semiclassical instanton approximation in the deep quantum tunneling regime. In effect, there is a continuous family of methods with these properties, parameterised by the strength of the Langevin friction. Here, we explore numerically how the approximation to quantum dynamics depends on this friction, with a particular emphasis on vibrational spectroscopy. We find that a broad range of frictions approaching optimal damping give similar results, and that these results are immune to both the resonance problem of RPMD and the curvature problem of CMD.« less

Adaptive Neuro-Fuzzy Inference System (ANFIS)-Based Models for Predicting the Weld Bead Width and Depth of Penetration from the Infrared Thermal Image of the Weld Pool

NASA Astrophysics Data System (ADS)

Subashini, L.; Vasudevan, M.

2012-02-01

Type 316 LN stainless steel is the major structural material used in the construction of nuclear reactors. Activated flux tungsten inert gas (A-TIG) welding has been developed to increase the depth of penetration because the depth of penetration achievable in single-pass TIG welding is limited. Real-time monitoring and control of weld processes is gaining importance because of the requirement of remoter welding process technologies. Hence, it is essential to develop computational methodologies based on an adaptive neuro fuzzy inference system (ANFIS) or artificial neural network (ANN) for predicting and controlling the depth of penetration and weld bead width during A-TIG welding of type 316 LN stainless steel. In the current work, A-TIG welding experiments have been carried out on 6-mm-thick plates of 316 LN stainless steel by varying the welding current. During welding, infrared (IR) thermal images of the weld pool have been acquired in real time, and the features have been extracted from the IR thermal images of the weld pool. The welding current values, along with the extracted features such as length, width of the hot spot, thermal area determined from the Gaussian fit, and thermal bead width computed from the first derivative curve were used as inputs, whereas the measured depth of penetration and weld bead width were used as output of the respective models. Accurate ANFIS models have been developed for predicting the depth of penetration and the weld bead width during TIG welding of 6-mm-thick 316 LN stainless steel plates. A good correlation between the measured and predicted values of weld bead width and depth of penetration were observed in the developed models. The performance of the ANFIS models are compared with that of the ANN models.

The Sequencing Bead Array (SBA), a Next-Generation Digital Suspension Array

PubMed Central

Akhras, Michael S.; Pettersson, Erik; Diamond, Lisa; Unemo, Magnus; Okamoto, Jennifer; Davis, Ronald W.; Pourmand, Nader

2013-01-01

Here we describe the novel Sequencing Bead Array (SBA), a complete assay for molecular diagnostics and typing applications. SBA is a digital suspension array using Next-Generation Sequencing (NGS), to replace conventional optical readout platforms. The technology allows for reducing the number of instruments required in a laboratory setting, where the same NGS instrument could be employed from whole-genome and targeted sequencing to SBA broad-range biomarker detection and genotyping. As proof-of-concept, a model assay was designed that could distinguish ten Human Papillomavirus (HPV) genotypes associated with cervical cancer progression. SBA was used to genotype 20 cervical tumor samples and, when compared with amplicon pyrosequencing, was able to detect two additional co-infections due to increased sensitivity. We also introduce in-house software Sphix, enabling easy accessibility and interpretation of results. The technology offers a multi-parallel, rapid, robust, and scalable system that is readily adaptable for a multitude of microarray diagnostic and typing applications, e.g. genetic signatures, single nucleotide polymorphisms (SNPs), structural variations, and immunoassays. SBA has the potential to dramatically change the way we perform probe-based applications, and allow for a smooth transition towards the technology offered by genomic sequencing. PMID:24116138

TiO2-photocatalyzed As(III) oxidation in a fixed-bed, flow-through reactor.

PubMed

Ferguson, Megan A; Hering, Janet G

2006-07-01

Compliance with the U.S. drinking water standard for arsenic (As) of 10 microg L(-1) is required in January 2006. This will necessitate implementation of treatment technologies for As removal by thousands of water suppliers. Although a variety of such technologies is available, most require preoxidation of As(III) to As(V) for efficient performance. Previous batch studies with illuminated TiO2 slurries have demonstrated that TiO2-photocatalyzed AS(III) oxidation occurs rapidly. This study examined reaction efficiency in a flow-through, fixed-bed reactor that provides a better model for treatment in practice. Glass beads were coated with mixed P25/sol gel TiO2 and employed in an upflow reactor irradiated from above. The reactor residence time, influent As(III) concentration, number of TiO2 coatings on the beads, solution matrix, and light source were varied to characterize this reaction and determine its feasibility for water treatment. Repeated usage of the same beads in multiple experiments or extended use was found to affect effluent As(V) concentrations but not the steady-state effluent As(III) concentration, which suggests that As(III) oxidation at the TiO2 surface undergoes dynamic sorption equilibration. Catalyst poisoning was not observed either from As(V) or from competitively adsorbing anions, although the higher steady-state effluent As(III) concentrations in synthetic groundwater compared to 5 mM NaNO3 indicated that competitive sorbates in the matrix partially hinder the reaction. A reactive transport model with rate constants proportional to incident light at each bead layer fit the experimental data well despite simplifying assumptions. TiO2-photocatalyzed oxidation of As(III) was also effective under natural sunlight. Limitations to the efficiency of As(III) oxidation in the fixed-bed reactor were attributable to constraints of the reactor geometry, which could be overcome by improved design. The fixed-bed TiO2 reactor offers an environmentally benign method for As(III) oxidation.

PCR-Free Detection of Genetically Modified Organisms Using Magnetic Capture Technology and Fluorescence Cross-Correlation Spectroscopy

PubMed Central

Zhou, Xiaoming; Xing, Da; Tang, Yonghong; Chen, Wei R.

2009-01-01

The safety of genetically modified organisms (GMOs) has attracted much attention recently. Polymerase chain reaction (PCR) amplification is a common method used in the identification of GMOs. However, a major disadvantage of PCR is the potential amplification of non-target DNA, causing false-positive identification. Thus, there remains a need for a simple, reliable and ultrasensitive method to identify and quantify GMO in crops. This report is to introduce a magnetic bead-based PCR-free method for rapid detection of GMOs using dual-color fluorescence cross-correlation spectroscopy (FCCS). The cauliflower mosaic virus 35S (CaMV35S) promoter commonly used in transgenic products was targeted. CaMV35S target was captured by a biotin-labeled nucleic acid probe and then purified using streptavidin-coated magnetic beads through biotin-streptavidin linkage. The purified target DNA fragment was hybridized with two nucleic acid probes labeled respectively by Rhodamine Green and Cy5 dyes. Finally, FCCS was used to detect and quantify the target DNA fragment through simultaneously detecting the fluorescence emissions from the two dyes. In our study, GMOs in genetically engineered soybeans and tomatoes were detected, using the magnetic bead-based PCR-free FCCS method. A detection limit of 50 pM GMOs target was achieved and PCR-free detection of GMOs from 5 µg genomic DNA with magnetic capture technology was accomplished. Also, the accuracy of GMO determination by the FCCS method is verified by spectrophotometry at 260 nm using PCR amplified target DNA fragment from GM tomato. The new method is rapid and effective as demonstrated in our experiments and can be easily extended to high-throughput and automatic screening format. We believe that the new magnetic bead-assisted FCCS detection technique will be a useful tool for PCR-free GMOs identification and other specific nucleic acids. PMID:19956680

Viscoelastic Mapping of Living Cell Interiors

NASA Astrophysics Data System (ADS)

Heinrich, Doris; Sackmann, Erich; Koehler, Jana; Gerisch, Guenther

2004-03-01

We performed spatially resolved mapping of the viscoelastic properties of the cytoplasm of living cell interiors. A magnetic tweezer was applied as a local probe for the investigation of active and passive transport inside the slime mold cells Dictyostelium discoideum. Fluorescence labeled components, i.e. the microtubulins, the endoplasmatic reticulum or the core, allow for the determination of the interaction of the magnetic probes with the cytoplasm. By comparing the trajectories of the magnetic beads in the presence of an external magnetic force and in the absence of an external force, we can measure the viscosity at any given position within the cell. These experiments show that the cytoplasm consists of soft pathways (yield stress less or equal 10 Pa) and hard pathways (yield stress less or equal 500 Pa). Selective actin, myosin II or microtubulin network removal in the living cells allows for the determination of the influence of these cell parts on the viscoelastic properties.

Ultrasensitive Electrochemical Detection of mRNA Using Branched DNA Amplifiers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, Xun; Liu, Guodong; Wang, Shengfu

2008-11-01

We describe here an ultrasensitive electrochemical detection of m RNA protocol without RNA purification and PCR amplification. The new m RNA electrical detection capability is coupled to the amplification feature of branched DNA (bDNA) technology and with the nagnetic beads based electrochemical bioassay.

Cross-craft interactions between metal and glass working: slag additions to early Anglo-Saxon red glass

NASA Astrophysics Data System (ADS)

Peake, James R. N.; Freestone, Ian C.

Opaque red glass has been extensively studied over the years, but its compositional complexity and variability means that the way in which it was manufactured is still not fully understood. Previous studies have suggested the use of metallurgical by-products in its manufacture, but until now the evidence has been limited. SEM-EDS analysis of glass beads from the early Anglo-Saxon cemetery complex at Eriswell, southeast England, has provided further insights into the production and technology of opaque red glass, which could only have been possible through invasive sampling. The matrix of the red glasses contains angular particles of slag, the main phases of which typically correspond to either fayalite (Fe2SiO4) or kirschsteinite (CaFeSiO4), orthosilicate (olivine-type) minerals characteristic of some copper- and iron-smelting slags. This material appears to have been added in part as a reducing agent, to promote the precipitation of sub-micrometer particles of the colorant phase, copper metal. Its use represents a sophisticated, if empirical, understanding of materials and can only have resulted through deliberate experimentation with metallurgical by-products by early glass workers. Slag also seems to have been added as a source of iron to colour `black' glass. The compositions of the opaque red glasses appear to be strongly paralleled by Merovingian beads from northern Europe and Anglo-Saxon beads from elsewhere in England, suggesting that this technology is likely to have been quite widespread.

Middle and Later Stone Age chronology of Kisese II rockshelter (UNESCO World Heritage Kondoa Rock-Art Sites), Tanzania

PubMed Central

Ranhorn, Kathryn L.; Kwekason, Amandus; Alex, Bridget; Laird, Myra F.; Marean, Curtis W.; Niespolo, Elizabeth; Nivens, Joelle; Mabulla, Audax Z. P.

2018-01-01

The archaeology of East Africa during the last ~65,000 years plays a central role in debates about the origins and dispersal of modern humans, Homo sapiens. Despite the historical importance of the region to these discussions, reliable chronologies for the nature, tempo, and timing of human behavioral changes seen among Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological assemblages are sparse. The Kisese II rockshelter in the Kondoa region of Tanzania, originally excavated in 1956, preserves a ≥ 6-m-thick archaeological succession that spans the MSA/LSA transition, with lithic artifacts such as Levallois and bladelet cores and backed microliths, the recurrent use of red ochre, and >5,000 ostrich eggshell beads and bead fragments. Twenty-nine radiocarbon dates on ostrich eggshell carbonate make Kisese II one of the most robust chronological sequences for understanding archaeological change over the last ~47,000 years in East Africa. In particular, ostrich eggshell beads and backed microliths appear by 46–42 ka cal BP and occur throughout overlying Late Pleistocene and Holocene strata. Changes in lithic technology suggest an MSA/LSA transition that began 39–34.3 ka, with typical LSA technologies in place by the Last Glacial Maximum. The timing of these changes demonstrates the time-transgressive nature of behavioral innovations often linked to the origins of modern humans, even within a single region of Africa. PMID:29489827

Cellular manipulation and patterning using ferromagnetic nanowires

NASA Astrophysics Data System (ADS)

Hultgren, Anne

Ferromagnetic nanowires are demonstrated as an effective tool to apply forces to living cells. Both magnetic cell separations and the magnetic patterning of cells on a substrate will be accomplished through the use of cell-nanowire interactions as well as nanowire-magnetic field interactions. When introduced into cultures of NIH-3T3 cells, the nanowires are internalized by cells via the integrin-mediated adhesion pathway without inflicting any toxic effects on the cell cycle over the course of several days. In addition, the length of the nanowires was found to have an effect on the cell-nanowire interactions when the cells were dissociated from the tissue culture dish. To compare the effectiveness of the nanowires as a means of manipulating cells to the current technology which is based on superparamagnetic beads, magnetic cell separations were performed with electrodeposited Ni nanowires 350 nm in diameter and 5--35 mum long in field gradients of 80 T/m. Single-pass separations of NIH-3T3 cells bound to nanowires achieve up to 81% purity with 85% yield, a dramatic improvement over the 55% purity and 20% yield obtained with the beads. The yield for the separations were found to be dependent on the length of the nanowires, and was maximized when the length of the nanowires equaled the diameter of the cells. This dependence was exploited to perform a size-selective magnetic separation. Substrates containing arrays of micro-magnets, fabricated using photolithography, were placed in cell cultures. These micro-magnet arrays create regions of locally strong magnetic field gradients to trap nanowires in specific locations on the substrate. These substrates were used in conjunction with fluid flow and a weak, externally applied magnetic field to create and control patterns of cells bound to nanowires. Controlled isolation of heterogeneous pairs and groups of cells will enable the study of the biochemistry of cell-cell contacts.

Surface Coatings on Lunar Volcanic Glasses

NASA Technical Reports Server (NTRS)

Wentworth, Susan J.; McKay, D. S.; Thomas,-Keprta, K. L.; Clemett, S. J.

2007-01-01

We are undertaking a detailed study of surface deposits on lunar volcanic glass beads. These tiny deposits formed by vapor condensation during cooling of the gases that drove the fire fountain eruptions responsible for the formation of the beads. Volcanic glass beads are present in most lunar soil samples in the returned lunar collection. The mare-composition beads formed as a result of fire-fountaining approx.3.4-3.7 Ga ago, within the age range of large-scale mare volcanism. Some samples from the Apollo 15 and Apollo 17 landing sites are enriched in volcanic spherules. Three major types of volcanic glass bead have been identified: Apollo 15 green glass, Apollo 17 orange glass, and Apollo 17 "black" glass. The Apollo 15 green glass has a primitive composition with low Ti. The high-Ti compositions of the orange and black glasses are essentially identical to each other but the black glasses are opaque because of quench crystallization. A poorly understood feature common to the Apollo 15 and 17 volcanic glasses is the presence of small deposits of unusual materials on their exterior surfaces. For example, early studies indicated that the Apollo 17 orange glasses had surface enrichments of In, Cd, Zn, Ga, Ge, Au, and Na, and possible Pb- and Zn-sulfides, but it was not possible to characterize the surface features in detail. Technological advances now permit us to examine such features in detail. Preliminary FE-TEM/X-ray studies of ultramicrotome sections of Apollo 15 green glass indicate that the surface deposits are heterogeneous and layered, with an inner layer consisting of Fe with minor S and an outer layer of Fe and no S, and scattered Zn enrichments. Layering in surface deposits has not been identified previously; it will be key to defining the history of lunar fire fountaining.

Broad adsorption of sepsis-related PAMP and DAMP molecules, mycotoxins, and cytokines from whole blood using CytoSorb® sorbent porous polymer beads.

PubMed

Gruda, Maryann C; Ruggeberg, Karl-Gustav; O'Sullivan, Pamela; Guliashvili, Tamaz; Scheirer, Andrew R; Golobish, Thomas D; Capponi, Vincent J; Chan, Phillip P

2018-01-01

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. In sepsis and septic shock, pathogen-associated molecular pattern molecules (PAMPS), such as bacterial exotoxins, cause direct cellular damage and/or trigger an immune response in the host often leading to excessive cytokine production, a maladaptive systemic inflammatory response syndrome response (SIRS), and tissue damage that releases DAMPs, such as activated complement and HMGB-1, into the bloodstream causing further organ injury. Cytokine reduction using extracorporeal blood filtration has been correlated with improvement in survival and clinical outcomes in experimental studies and clinical reports, but the ability of this technology to reduce a broader range of inflammatory mediators has not been well-described. This study quantifies the size-selective adsorption of a wide range of sepsis-related inflammatory bacterial and fungal PAMPs, DAMPs and cytokines, in a single compartment, in vitro whole blood recirculation system. Purified proteins were added to whole blood at clinically relevant concentrations and recirculated through a device filled with CytoSorb® hemoadsorbent polymer beads (CytoSorbents Corporation, USA) or control (no bead) device in vitro. Except for the TNF-α trimer, hemoadsorption through porous polymer bead devices reduced the levels of a broad spectrum of cytokines, DAMPS, PAMPS and mycotoxins by more than 50 percent. This study demonstrates that CytoSorb® hemoadsorbent polymer beads efficiently remove a broad spectrum of toxic PAMPS and DAMPS from blood providing an additional means of reducing the uncontrolled inflammatory cascade that contributes to a maladaptive SIRS response, organ dysfunction and death in patients with a broad range of life-threatening inflammatory conditions such as sepsis, toxic shock syndrome, necrotizing fasciitis, and other severe inflammatory conditions.

Commercial glass beads as TLDs in radiotherapy produced by different manufacturers

NASA Astrophysics Data System (ADS)

Jafari, S. M.; Bates, N. M.; Jupp, T.; Abdul Sani, S. F.; Nisbet, A.; Bradley, D. A.

2017-08-01

While commercial jewellery glass beads offer the basis of novel radiotherapy TL dosimetry (Jafari et al. 2014a,b,c, 2015a,b), detailed study of TL variation is required for the products from various manufacturers. Investigation is made for glass beads from four manufacturers from four countries: China (Rocaille), Japan (Mill Hill), Indonesia (TOHO™) and Czech Republic (Czech). Sample composition was determined using an energy-dispersive X-ray unit coupled to a scanning electron microscope. Values of mass attenuation coefficient, μ/ρ, as a function of photon energy were then calculated for photons of energy 1 keV to 10 MeV, using the National Institute of Standards and Technology XCOM program. Radiation and energy response were determined using X-rays generated at accelerating potentials from 80 kVp to 6 MV (TPR20/10=0.670). All bead types showed TL to be linear with dose (R2>0.999). Glow curve dosimetric peaks reached a maximum value at 300 °C for the Toho and 290 °C for the Czech and Mill Hill products but was between 200-250 °C for the Rocaille product. Radiation sensitivity following mass normalisation varied within an order of magnitude; Toho samples showed the greatest and Rocaille the least sensitivity. For the Toho, Czech, Rocaille and Mill Hill samples the energy responses at 80 kVp were 5.0, 4.0, 3.6 and 3.3 times that obtained at 6 MV. All four glass bead types offer potential use as TL dosimeters over doses commonly applied in radiotherapy. Energy response variation was <1% at 6 MV but significant variation was found for photon beam energies covering the kV range; careful characterisation is required if use at this range is intended.

Detection of HLA Antibodies in Organ Transplant Recipients – Triumphs and Challenges of the Solid Phase Bead Assay

PubMed Central

Tait, Brian D.

2016-01-01

This review outlines the development of human leukocyte antigen (HLA) antibody detection assays and their use in organ transplantation in both antibody screening and crossmatching. The development of sensitive solid phase assays such as the enzyme-linked immunosorbent assay technique, and in particular the bead-based technology has revolutionized this field over the last 10–15 years. This revolution however has created a new paradigm in clinical decision making with respect to the detection of low level pretransplant HLA sensitization and its clinical relevance. The relative sensitivities of the assays used are discussed and the relevance of conflicting inter-assay results. Each assay has its advantages and disadvantages and these are discussed. Over the last decade, the bead-based assay utilizing the Luminex® fluorocytometer instrument has become established as the “gold standard” for HLA antibody testing. However, there are still unresolved issues surrounding this technique, such as the presence of denatured HLA molecules on the beads which reveal cryptic epitopes and the issue of appropriate fluorescence cut off values for positivity. The assay has been modified to detect complement binding (CB) in addition to non-complement binding (NCB) HLA antibodies although the clinical relevance of the CB and NCB IgG isotypes is not fully resolved. The increase sensitivity of the Luminex® bead assay over the complement-dependent cytotoxicity crossmatch has permitted the concept of the “virtual crossmatch” whereby the crossmatch is predicted to a high degree of accuracy based on the HLA antibody specificities detected by the solid phase assay. Dialog between clinicians and laboratory staff on an individual patient basis is essential for correct clinical decision making based on HLA antibody results obtained by the various techniques. PMID:28018342

Scanning fluorescent microscopy is an alternative for quantitative fluorescent cell analysis.

PubMed

Varga, Viktor Sebestyén; Bocsi, József; Sipos, Ferenc; Csendes, Gábor; Tulassay, Zsolt; Molnár, Béla

2004-07-01

Fluorescent measurements on cells are performed today with FCM and laser scanning cytometry. The scientific community dealing with quantitative cell analysis would benefit from the development of a new digital multichannel and virtual microscopy based scanning fluorescent microscopy technology and from its evaluation on routine standardized fluorescent beads and clinical specimens. We applied a commercial motorized fluorescent microscope system. The scanning was done at 20 x (0.5 NA) magnification, on three channels (Rhodamine, FITC, Hoechst). The SFM (scanning fluorescent microscopy) software included the following features: scanning area, exposure time, and channel definition, autofocused scanning, densitometric and morphometric cellular feature determination, gating on scatterplots and frequency histograms, and preparation of galleries of the gated cells. For the calibration and standardization Immuno-Brite beads were used. With application of shading compensation, the CV of fluorescence of the beads decreased from 24.3% to 3.9%. Standard JPEG image compression until 1:150 resulted in no significant change. The change of focus influenced the CV significantly only after +/-5 microm error. SFM is a valuable method for the evaluation of fluorescently labeled cells. Copyright 2004 Wiley-Liss, Inc.

Statistical optimization of arsenic biosorption by microbial enzyme via Ca-alginate beads.

PubMed

Banerjee, Suchetana; Banerjee, Anindita; Sarkar, Priyabrata

2018-04-16

Bioremediation of arsenic using green technology via microbial enzymes has attracted scientists due to its simplicity and cost effectiveness. Statistical optimization of arsenate bioremediation was conducted by the enzyme arsenate reductase extracted from arsenic tolerant bacterium Pseudomonas alcaligenes. Response surface methodology based on Box-Behnken design matrix was performed to determine the optimal operational conditions of a multivariable system and their interactive effects on the bioremediation process. The highest biosorptive activity of 96.2 µg gm -1 of beads was achieved under optimized conditions (pH = 7.0; As (V) concentration = 1000 ppb; time = 2 h). SEM analysis showed the morphological changes on the surface of enzyme immobilized gluteraldehyde crosslinked Ca-alginate beads. The immobilized enzyme retained its activity for 8 cycles. ANOVA with a high correlation coefficient (R 2 > 0.99) and lower "Prob > F"value (<0.0001) corroborated the second-order polynomial model for the biosorption process. This study on the adsorptive removal of As (V) by enzyme-loaded biosorbent revealed a possible way of its application in large scale treatment of As (V)-contaminated water bodies.

High throughput imaging cytometer with acoustic focussing.

PubMed

Zmijan, Robert; Jonnalagadda, Umesh S; Carugo, Dario; Kochi, Yu; Lemm, Elizabeth; Packham, Graham; Hill, Martyn; Glynne-Jones, Peter

2015-10-31

We demonstrate an imaging flow cytometer that uses acoustic levitation to assemble cells and other particles into a sheet structure. This technique enables a high resolution, low noise CMOS camera to capture images of thousands of cells with each frame. While ultrasonic focussing has previously been demonstrated for 1D cytometry systems, extending the technology to a planar, much higher throughput format and integrating imaging is non-trivial, and represents a significant jump forward in capability, leading to diagnostic possibilities not achievable with current systems. A galvo mirror is used to track the images of the moving cells permitting exposure times of 10 ms at frame rates of 50 fps with motion blur of only a few pixels. At 80 fps, we demonstrate a throughput of 208 000 beads per second. We investigate the factors affecting motion blur and throughput, and demonstrate the system with fluorescent beads, leukaemia cells and a chondrocyte cell line. Cells require more time to reach the acoustic focus than beads, resulting in lower throughputs; however a longer device would remove this constraint.

76 FR 14058 - Notice of Inventory Completion: Fremont County Coroner, Riverton, WY

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-15

... associated funerary objects are 2 fragments of freshwater clam shells, 32 dentalia shell beads, 2 bird bone beads, 8 chokecherry seed beads, 162 bone heishi-style beads, 158 lignite heishi-style beads, 5 fragmentary bone heishi-style beads, 1 shell bead, and 3 chert microflakes. The Sinks Canyon site is located...

Lab-on-a-Chip: Frontier Science in the Classroom

ERIC Educational Resources Information Center

Wietsma, Jan Jaap; van der Veen, Jan T.; Buesink, Wilfred; van den Berg, Albert; Odijk, Mathieu

2018-01-01

Lab-on-a-chip technology is brought into the classroom through development of a lesson series with hands-on practicals. Students can discover the principles of microfluidics with different practicals covering laminar flow, micromixing, and droplet generation, as well as trapping and counting beads. A quite affordable novel production technique…

Magnetic bead purification of labeled DNA fragments forhigh-throughput capillary electrophoresis sequencing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elkin, Christopher; Kapur, Hitesh; Smith, Troy

2001-09-15

We have developed an automated purification method for terminator sequencing products based on a magnetic bead technology. This 384-well protocol generates labeled DNA fragments that are essentially free of contaminates for less than $0.005 per reaction. In comparison to laborious ethanol precipitation protocols, this method increases the phred20 read length by forty bases with various DNA templates such as PCR fragments, Plasmids, Cosmids and RCA products. Our method eliminates centrifugation and is compatible with both the MegaBACE 1000 and ABIPrism 3700 capillary instruments. As of September 2001, this method has produced over 1.6 million samples with 93 percent averaging 620more » phred20 bases as part of Joint Genome Institutes Production Process.« less

On-chip immunomagnetic separation of bacteria by in-flow dynamic manipulation of paramagnetic beads

NASA Astrophysics Data System (ADS)

Ahmed, Shakil; Noh, Jong Wook; Hoyland, James; de Oliveira Hansen, Roana; Erdmann, Helmut; Rubahn, Horst-Günter

2016-11-01

Every year, millions of people all over the world fall ill due to the consumption of unsafe food, where consumption of contaminated and spoiled animal origin product is the main cause for diseases due to bacterial growth. This leads to an intense need for efficient methods for detection of food-related bacteria. In this work, we present a method for integration of immunomagnetic separation of bacteria into microfluidic technology by applying an alternating magnetic field, which manipulates the paramagnetic beads into a sinusoidal path across the whole microchannel, increasing the probability for bacteria capture. The optimum channel geometry, flow rate and alternating magnetic field frequency were investigated, resulting in a capture efficiency of 68 %.

Heterogeneous immunoassays using magnetic beads on a digital microfluidic platform.

PubMed

Sista, Ramakrishna S; Eckhardt, Allen E; Srinivasan, Vijay; Pollack, Michael G; Palanki, Srinivas; Pamula, Vamsee K

2008-12-01

A digital microfluidic platform for performing heterogeneous sandwich immunoassays based on efficient handling of magnetic beads is presented in this paper. This approach is based on manipulation of discrete droplets of samples and reagents using electrowetting without the need for channels where the droplets are free to move laterally. Droplet-based manipulation of magnetic beads therefore does not suffer from clogging of channels. Immunoassays on a digital microfluidic platform require the following basic operations: bead attraction, bead washing, bead retention, and bead resuspension. Several parameters such as magnetic field strength, pull force, position, and buffer composition were studied for effective bead operations. Dilution-based washing of magnetic beads was demonstrated by immobilizing the magnetic beads using a permanent magnet and splitting the excess supernatant using electrowetting. Almost 100% bead retention was achieved after 7776-fold dilution-based washing of the supernatant. Efficient resuspension of magnetic beads was achieved by transporting a droplet with magnetic beads across five electrodes on the platform and exploiting the flow patterns within the droplet to resuspend the beads. All the magnetic-bead droplet operations were integrated together to generate standard curves for sandwich heterogeneous immunoassays on human insulin and interleukin-6 (IL-6) with a total time to result of 7 min for each assay.

Heterogeneous Immunoassays Using Magnetic beads On a Digital Microfluidic Platform

PubMed Central

Sista, Ramakrishna S.; Eckhardt, Allen E.; Srinivasan, Vijay; Pollack, Michael G.; Palanki, Srinivas; Pamula, Vamsee K.

2009-01-01

A digital microfluidic platform for performing heterogeneous sandwich immunoassays based on efficient handling of magnetic beads is presented in this paper. This approach is based on manipulation of discrete droplets of samples and reagents using electrowetting without the need for channels where the droplets are free to move laterally. Droplet-based manipulation of magnetic beads therefore does not suffer from clogging of channels. Immunoassays on a digital microfluidic platform require the following basic operations: bead attraction, bead washing, bead retention, and bead resuspension. Several parameters such as magnetic field strength, pull force, position, and buffer composition were studied for effective bead operations. Dilution-based washing of magnetic beads was demonstrated by immobilizing the magnetic beads using a permanent magnet and splitting the excess supernatant using electrowetting. Almost 100% bead retention was achieved after 7776 fold dilution-based washing of the supernatant. Efficient resuspension of magnetic beads was achieved by transporting a droplet with magnetic beads across five electrodes on the platform and exploiting the flow patterns within the droplet to resuspend the beads. All the magnetic-bead droplet operations were integrated together to generate standard curves for sandwich heterogeneous immunoassays on Human Insulin and Interleukin-6 (IL-6) with a total time to result of seven minutes for each assay. PMID:19023486

Influence of Immobilized Biomolecules on Magnetic Bead Plug Formation and Retention in Capillary Electrophoresis

PubMed Central

Henken, Rachel L.; Chantiwas, Rattikan; Gilman, S. Douglass

2012-01-01

Significant changes in the formation and retention of magnetic bead plugs in a capillary during electrophoresis were studied, and it was demonstrated that these effects were due to the type of biological molecule immobilized on the surface of these beads. Three biological molecules, an antibody, an oligonucleotide and alkaline phosphatase, were attached to otherwise identical streptavidin-coated magnetic beads through biotin-avidin binding in order to isolate differences in bead immobilization in a magnetic field resulting from the type of biological molecule immobilized on the bead surface. Alkaline phosphatase also was attached to the magnetic beads using epoxy groups on the bead surfaces (instead of avidin-biotin binding) to study the impact of immobilization chemistry. The formation and retention of magnetic bead plugs were studied quantitatively using light scattering detection of magnetic particles eluting from the bead plugs and qualitatively using microscopy. Both the type of biomolecule immobilized on the magnetic bead surface and the chemistry used to link the biomolecule to the magnetic bead impacted the formation and retention of the bead plugs. PMID:22437880

The Fate of Equality in a Technological Civilization

ERIC Educational Resources Information Center

Stivers, Richard

2008-01-01

The meaning of equality has been radically altered since the Enlightenment. In the 18th century, equality acquired political and economic meanings specifically in the contexts of democracy and capitalism. Today, the context in which equality is understood and practiced is technology as our most immediate and compelling environment. Moreover, the…

Analytical and statistical consideration on the use of the ISAG-ICAR-SNP bovine panel for parentage control, using the Illumina BeadChip technology: example on the German Holstein population.

PubMed

Schütz, Ekkehard; Brenig, Bertram

2015-02-05

Parentage control is moving from short tandem repeats- to single nucleotide polymorphism (SNP) systems. For SNP-based parentage control in cattle, the ISAG-ICAR Committee proposes a set of 100/200 SNPs but quality criteria are lacking. Regarding German Holstein-Friesian cattle with only a limited number of evaluated individuals, the exclusion probability is not well-defined. We propose a statistical procedure for excluding single SNPs from parentage control, based on case-by-case evaluation of the GenCall score, to minimize parentage exclusion, based on miscalled genotypes. Exclusion power of the ISAG-ICAR SNPs used for the German Holstein-Friesian population was adjusted based on the results of more than 25,000 individuals. Experimental data were derived from routine genomic selection analyses of the German Holstein-Friesian population using the Illumina BovineSNP50 v2 BeadChip (20,000 individuals) or the EuroG10K variant (7000 individuals). Averages and standard deviations of GenCall scores for the 200 SNPs of the ISAG-ICAR recommended panel were calculated and used to calculate the downward Z-value. Based on minor allelic frequencies in the Holstein-Friesian population, one minus exclusion probability was equal to 1.4×10⁻¹⁰ and 7.2×10⁻²⁶, with one and two parents, respectively. Two monomorphic SNPs from the 100-SNP ISAG-ICAR core-panel did not contribute. Simulation of 10,000 parentage control combinations, using the GenCall score data from both BeadChips, showed that with a Z-value greater than 3.66 only about 2.5% parentages were excluded, based on the ISAG-ICAR recommendations (core-panel: ≥ 90 SNPs for one, ≥ 85 SNPs for two parents). When applied to real data from 1750 single parentage assessments, the optimal threshold was determined to be Z = 5.0, with only 34 censored cases and reduction to four (0.2%) doubtful parentages. About 70 parentage exclusions due to weak genotype calls were avoided, whereas true exclusions (n = 34) were unaffected. Using SNPs for parentage evaluation provides a high exclusion power also for parent identification. SNPs with a low GenCall score show a high tendency towards intra-molecular secondary structures and substantially contribute to false exclusion of parentages. We propose a method that controls this error without excluding too many parent combinations from the evaluation.

A highly efficient bead extraction technique with low bead number for digital microfluidic immunoassay

PubMed Central

Tsai, Po-Yen; Lee, I-Chin; Hsu, Hsin-Yun; Huang, Hong-Yuan; Fan, Shih-Kang; Liu, Cheng-Hsien

2016-01-01

Here, we describe a technique to manipulate a low number of beads to achieve high washing efficiency with zero bead loss in the washing process of a digital microfluidic (DMF) immunoassay. Previously, two magnetic bead extraction methods were reported in the DMF platform: (1) single-side electrowetting method and (2) double-side electrowetting method. The first approach could provide high washing efficiency, but it required a large number of beads. The second approach could reduce the required number of beads, but it was inefficient where multiple washes were required. More importantly, bead loss during the washing process was unavoidable in both methods. Here, an improved double-side electrowetting method is proposed for bead extraction by utilizing a series of unequal electrodes. It is shown that, with proper electrode size ratio, only one wash step is required to achieve 98% washing rate without any bead loss at bead number less than 100 in a droplet. It allows using only about 25 magnetic beads in DMF immunoassay to increase the number of captured analytes on each bead effectively. In our human soluble tumor necrosis factor receptor I (sTNF-RI) model immunoassay, the experimental results show that, comparing to our previous results without using the proposed bead extraction technique, the immunoassay with low bead number significantly enhances the fluorescence signal to provide a better limit of detection (3.14 pg/ml) with smaller reagent volumes (200 nl) and shorter analysis time (<1 h). This improved bead extraction technique not only can be used in the DMF immunoassay but also has great potential to be used in any other bead-based DMF systems for different applications. PMID:26858807

Seeds used for Bodhi beads in China

PubMed Central

2014-01-01

Background Bodhi beads are a Buddhist prayer item made from seeds. Bodhi beads have a large and emerging market in China, and demand for the beads has particularly increased in Buddhism regions, especially Tibet. Many people have started to focus on and collect Bodhi beads and to develop a Bodhi bead culture. But no research has examined the source plants of Bodhi beads. Therefore, ethnobotanical surveys were conducted in six provinces of China to investigate and document Bodhi bead plants. Reasons for the development of Bodhi bead culture were also discussed. Methods Six provinces of China were selected for market surveys. Information was collected using semi-structured interviews, key informant interviews, and participatory observation with traders, tourists, and local residents. Barkhor Street in Lhasa was focused on during market surveys because it is one of the most popular streets in China. Results Forty-seven species (including 2 varieties) in 19 families and 39 genera represented 52 types of Bodhi beads that were collected. The most popular Bodhi bead plants have a long history and religious significance. Most Bodhi bead plants can be used as medicine or food, and their seeds or fruits are the main elements in these uses. ‘Bodhi seeds’ have been historically used in other countries for making ornaments, especially seeds of the legume family. Many factors helped form Bodhi bead culture in China, but its foundation was in Indian Buddhist culture. Conclusions As one of the earliest adornment materials, seeds played an important role for human production and life. Complex sources of Bodhi beads have different cultural and historical significance. People bought and collected Bodhi beads to reflect their love and admiration for the plants. Thus, the documentation of Bodhi bead plants can serve as a basis for future investigation of Bodhi bead culture and modern Buddhist culture. PMID:24479788

Seeds used for Bodhi beads in China.

PubMed

Li, Feifei; Li, Jianqin; Liu, Bo; Zhuo, Jingxian; Long, Chunlin

2014-01-30

Bodhi beads are a Buddhist prayer item made from seeds. Bodhi beads have a large and emerging market in China, and demand for the beads has particularly increased in Buddhism regions, especially Tibet. Many people have started to focus on and collect Bodhi beads and to develop a Bodhi bead culture. But no research has examined the source plants of Bodhi beads. Therefore, ethnobotanical surveys were conducted in six provinces of China to investigate and document Bodhi bead plants. Reasons for the development of Bodhi bead culture were also discussed. Six provinces of China were selected for market surveys. Information was collected using semi-structured interviews, key informant interviews, and participatory observation with traders, tourists, and local residents. Barkhor Street in Lhasa was focused on during market surveys because it is one of the most popular streets in China. Forty-seven species (including 2 varieties) in 19 families and 39 genera represented 52 types of Bodhi beads that were collected. The most popular Bodhi bead plants have a long history and religious significance. Most Bodhi bead plants can be used as medicine or food, and their seeds or fruits are the main elements in these uses. 'Bodhi seeds' have been historically used in other countries for making ornaments, especially seeds of the legume family. Many factors helped form Bodhi bead culture in China, but its foundation was in Indian Buddhist culture. As one of the earliest adornment materials, seeds played an important role for human production and life. Complex sources of Bodhi beads have different cultural and historical significance. People bought and collected Bodhi beads to reflect their love and admiration for the plants. Thus, the documentation of Bodhi bead plants can serve as a basis for future investigation of Bodhi bead culture and modern Buddhist culture.

Metal-Containing Polystyrene Beads as Standards for Mass Cytometry

PubMed Central

Abdelrahman, Ahmed I.; Ornatsky, Olga; Bandura, Dmitry; Kinach, Robert; Dai, Sheng; Thickett, Stuart C.; Tanner, Scott

2010-01-01

We examine the suitability of metal-containing polystyrene beads for the calibration of a mass cytometer instrument, a single particle analyser based on an inductively coupled plasma ion source and a time of flight mass spectrometer. These metal-containing beads are also verified for their use as internal standards for this instrument. These beads were synthesized by multiple-stage dispersion polymerization with acrylic acid as a comonomer. Acrylic acid acts as a ligand to anchor the metal ions within the interior of the beads. Mass cytometry enabled the bead-by-bead measurement of the metal-content and determination of the metal-content distribution. Beads synthesized by dispersion polymerization that involved three stages were shown to have narrower bead-to-bead variation in their lanthanide content than beads synthesized by 2-stage dispersion polymerization. The beads exhibited insignificant release of their lanthanide content to aqueous solutions of different pHs over a period of six months. When mixed with KG1a or U937 cell lines, metal-containing polymer beads were shown not to affect the mass cytometry response to the metal content of element-tagged antibodies specifically attached to these cells. PMID:20390041

Metal-Containing Polystyrene Beads as Standards for Mass Cytometry.

PubMed

Abdelrahman, Ahmed I; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Kinach, Robert; Dai, Sheng; Thickett, Stuart C; Tanner, Scott; Winnik, Mitchell A

2010-01-01

We examine the suitability of metal-containing polystyrene beads for the calibration of a mass cytometer instrument, a single particle analyser based on an inductively coupled plasma ion source and a time of flight mass spectrometer. These metal-containing beads are also verified for their use as internal standards for this instrument. These beads were synthesized by multiple-stage dispersion polymerization with acrylic acid as a comonomer. Acrylic acid acts as a ligand to anchor the metal ions within the interior of the beads. Mass cytometry enabled the bead-by-bead measurement of the metal-content and determination of the metal-content distribution. Beads synthesized by dispersion polymerization that involved three stages were shown to have narrower bead-to-bead variation in their lanthanide content than beads synthesized by 2-stage dispersion polymerization. The beads exhibited insignificant release of their lanthanide content to aqueous solutions of different pHs over a period of six months. When mixed with KG1a or U937 cell lines, metal-containing polymer beads were shown not to affect the mass cytometry response to the metal content of element-tagged antibodies specifically attached to these cells.

First demonstration of laser engagement of 1-Hz-injected flying pellets and neutron generation.

PubMed

Komeda, Osamu; Nishimura, Yasuhiko; Mori, Yoshitaka; Hanayama, Ryohei; Ishii, Katsuhiro; Nakayama, Suisei; Kitagawa, Yoneyoshi; Sekine, Takashi; Sato, Nakahiro; Kurita, Takashi; Kawashima, Toshiyuki; Kan, Hirofumi; Nakamura, Naoki; Kondo, Takuya; Fujine, Manabu; Azuma, Hirozumi; Motohiro, Tomoyoshi; Hioki, Tatsumi; Kakeno, Mitsutaka; Sunahara, Atsushi; Sentoku, Yasuhiko; Miura, Eisuke

2013-01-01

Pellet injection and repetitive laser illumination are key technologies for realizing inertial fusion energy. Numerous studies have been conducted on target suppliers, injectors, and tracking systems for flying pellet engagement. Here we for the first time demonstrate the pellet injection, counter laser beams' engagement and neutron generation. Deuterated polystyrene (CD) bead pellets, after free-falling for a distance of 18 cm at 1 Hz, are successfully engaged by two counter laser beams from a diode-pumped, ultra-intense laser HAMA. The laser energy, pulse duration, wavelength, and the intensity are 0.63 J per beam, 104 fs, and 811 nm, 4.7 × 10(18) W/cm(2), respectively. The irradiated pellets produce D(d,n)(3)He-reacted neutrons with a maximum yield of 9.5 × 10(4)/4π sr/shot. Moreover, the laser is found out to bore a straight channel with 10 μm-diameter through the 1-mm-diameter beads. The results indicate potentially useful technologies and findings for the next step in realizing inertial fusion energy.

First demonstration of laser engagement of 1-Hz-injected flying pellets and neutron generation

PubMed Central

Komeda, Osamu; Nishimura, Yasuhiko; Mori, Yoshitaka; Hanayama, Ryohei; Ishii, Katsuhiro; Nakayama, Suisei; Kitagawa, Yoneyoshi; Sekine, Takashi; Sato, Nakahiro; Kurita, Takashi; Kawashima, Toshiyuki; Kan, Hirofumi; Nakamura, Naoki; Kondo, Takuya; Fujine, Manabu; Azuma, Hirozumi; Motohiro, Tomoyoshi; Hioki, Tatsumi; Kakeno, Mitsutaka; Sunahara, Atsushi; Sentoku, Yasuhiko; Miura, Eisuke

2013-01-01

Pellet injection and repetitive laser illumination are key technologies for realizing inertial fusion energy. Numerous studies have been conducted on target suppliers, injectors, and tracking systems for flying pellet engagement. Here we for the first time demonstrate the pellet injection, counter laser beams' engagement and neutron generation. Deuterated polystyrene (CD) bead pellets, after free-falling for a distance of 18 cm at 1 Hz, are successfully engaged by two counter laser beams from a diode-pumped, ultra-intense laser HAMA. The laser energy, pulse duration, wavelength, and the intensity are 0.63 J per beam, 104 fs, and 811 nm, 4.7 × 1018 W/cm2, respectively. The irradiated pellets produce D(d,n)3He-reacted neutrons with a maximum yield of 9.5 × 104/4π sr/shot. Moreover, the laser is found out to bore a straight channel with 10 μm-diameter through the 1-mm-diameter beads. The results indicate potentially useful technologies and findings for the next step in realizing inertial fusion energy. PMID:24008696

Jllumina - A comprehensive Java-based API for statistical Illumina Infinium HumanMethylation450 and Infinium MethylationEPIC BeadChip data processing.

PubMed

Almeida, Diogo; Skov, Ida; Lund, Jesper; Mohammadnejad, Afsaneh; Silva, Artur; Vandin, Fabio; Tan, Qihua; Baumbach, Jan; Röttger, Richard

2016-10-01

Measuring differential methylation of the DNA is the nowadays most common approach to linking epigenetic modifications to diseases (called epigenome-wide association studies, EWAS). For its low cost, its efficiency and easy handling, the Illumina HumanMethylation450 BeadChip and its successor, the Infinium MethylationEPIC BeadChip, is the by far most popular techniques for conduction EWAS in large patient cohorts. Despite the popularity of this chip technology, raw data processing and statistical analysis of the array data remains far from trivial and still lacks dedicated software libraries enabling high quality and statistically sound downstream analyses. As of yet, only R-based solutions are freely available for low-level processing of the Illumina chip data. However, the lack of alternative libraries poses a hurdle for the development of new bioinformatic tools, in particular when it comes to web services or applications where run time and memory consumption matter, or EWAS data analysis is an integrative part of a bigger framework or data analysis pipeline. We have therefore developed and implemented Jllumina, an open-source Java library for raw data manipulation of Illumina Infinium HumanMethylation450 and Infinium MethylationEPIC BeadChip data, supporting the developer with Java functions covering reading and preprocessing the raw data, down to statistical assessment, permutation tests, and identification of differentially methylated loci. Jllumina is fully parallelizable and publicly available at http://dimmer.compbio.sdu.dk/download.html.

The novel Group A Streptococcus antigen SpnA combined with bead-based immunoassay technology improves streptococcal serology for the diagnosis of acute rheumatic fever.

PubMed

Hanson-Manful, Paulina; Whitcombe, Alana L; Young, Paul G; Atatoa Carr, Polly E; Bell, Anita; Didsbury, Alicia; Mitchell, Edwin A; Dunbar, P Rod; Proft, Thomas; Moreland, Nicole J

2018-04-01

Streptococcal serology provides evidence of prior Group A Streptococcus (GAS) exposure, crucial to the diagnosis of acute rheumatic fever (ARF) and post-streptococcal glomerulonephritis. However, current tests, which measure anti-streptolysin-O and anti-DNaseB antibodies, are limited by false positives in GAS endemic settings, and incompatible methodology requiring the two tests to be run in parallel. The objective was to improve streptococcal serology by combining the novel GAS antigen, SpnA, with streptolysin-O and DNaseB in a contemporary, bead-based immunoassay. Recombinant streptolysin-O, DNAseB and SpnA were conjugated to polystyrene beads with unique fluorescence positions so antibody binding to all three antigens could be detected simultaneously by cytometric bead array. Multiplex assays were run on sera collected in three groups: ARF; ethnically matched healthy children; and healthy adults. The ability of the antigens to detect a previous GAS exposure in ARF was assessed using the 80th centile of the healthy children group as cut-off (upper limit of normal). SpnA had the highest sensitivity at 88%, compared with 75% for streptolysin-O and 56% for DNaseB. SpnA has favorable immunokinetics for streptococcal serology, and can be combined with anti-streptolysin-O and anti-DNaseB in a multiplex format to improve efficiency and accuracy. Copyright © 2017 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Establishment and evaluation of a bead-based luminex assay allowing simultaneous quantification of equine IL-12 and IFN-γ.

PubMed

Duran, Maria Carolina; Willenbrock, Saskia; Müller, Jessika-M V; Nolte, Ingo; Feige, Karsten; Murua Escobar, Hugo

2013-04-01

Interleukin-12 (IL-12) and interferon gamma (IFN-γ) are key cytokines in immunemediated equine melanoma therapy. Currently, a method for accurate simultaneous quantification of these equine cytokines is lacking. Therefore, we sought to establish an assay that allows for accurate and simultaneous quantification of equine IL-12 (eIL-12) and IFN-γ (eIFN-γ). Several antibodies were evaluated for cross-reactivity to eIL-12 and eIFN-γ and were used to establish a bead-based Luminex assay, which was subsequently applied to quantify cytokine concentrations in biological samples. Cytokine detection ranged from 31.5-5,000 pg/ml and 15-10,000 pg/ml for eIL-12 and eIFN-γ, respectively. eIL-12 was detected in supernatants of stimulated peripheral blood mononuclear cells (PBMCs) and supernatants/cell lysates of eIL-12 expression plasmid-transfected cells. Low or undetectable cytokine concentrations were measured in negative controls. In equine serum samples, the mean measured eIL-12 concentration was 1,374 ± 8 pg/ml. The bead-based assay and ELISA for eIFN-γ used to measure eIFN-γ concentrations, showed similar concentrations. Results demonstrate, to our knowledge for the first time, that cross-reactive antibody pairs to eIL-12 and eIFN-γ and Luminex bead-based technology allow for accurate, simultaneous and multiplexed quantification of these key cytokines in biological samples.

Polystyrene Core-Silica Shell Particles with Defined Nanoarchitectures as a Versatile Platform for Suspension Array Technology.

PubMed

Sarma, Dominik; Gawlitza, Kornelia; Rurack, Knut

2016-04-19

The need for rapid and high-throughput screening in analytical laboratories has led to significant growth in interest in suspension array technologies (SATs), especially with regard to cytometric assays targeting a low to medium number of analytes. Such SAT or bead-based assays rely on spherical objects that constitute the analytical platform. Usually, functionalized polymer or silica (SiO2) microbeads are used which each have distinct advantages and drawbacks. In this paper, we present a straightforward synthetic route to highly monodisperse SiO2-coated polystyrene core-shell (CS) beads for SAT with controllable architectures from smooth to raspberry- and multilayer-like shells by varying the molecular weight of poly(vinylpyrrolidone) (PVP), which was used as the stabilizer of the cores. The combination of both organic polymer core and a structurally controlled inorganic SiO2 shell in one hybrid particle holds great promises for flexible next-generation design of the spherical platform. The particles were characterized by electron microscopy (SEM, T-SEM, and TEM), thermogravimetry, flow cytometry, and nitrogen adsorption/desorption, offering comprehensive information on the composition, size, structure, and surface area. All particles show ideal cytometric detection patterns and facile handling due to the hybrid structure. The beads are endowed with straightforward modification possibilities through the defined SiO2 shells. We successfully implemented the particles in fluorometric SAT model assays, illustrating the benefits of tailored surface area which is readily available for small-molecule anchoring. Very promising assay performance was shown for DNA hybridization assays with quantification limits down to 8 fmol.

The optics inside an automated single molecule array analyzer

NASA Astrophysics Data System (ADS)

McGuigan, William; Fournier, David R.; Watson, Gary W.; Walling, Les; Gigante, Bill; Duffy, David C.; Rissin, David M.; Kan, Cheuk W.; Meyer, Raymond E.; Piech, Tomasz; Fishburn, Matthew W.

2014-02-01

Quanterix and Stratec Biomedical have developed an instrument that enables the automated measurement of multiple proteins at concentration ~1000 times lower than existing immunoassays. The instrument is based on Quanterix's proprietary Single Molecule Array technology (Simoa™ ) that facilitates the detection and quantification of biomarkers previously difficult to measure, thus opening up new applications in life science research and in-vitro diagnostics. Simoa is based on trapping individual beads in arrays of femtoliter-sized wells that, when imaged with sufficient resolution, allows for counting of single molecules associated with each bead. When used to capture and detect proteins, this approach is known as digital ELISA (Enzyme-linked immunosorbent assay). The platform developed is a merger of many science and engineering disciplines. This paper concentrates on the optical technologies that have enabled the development of a fully-automated single molecule analyzer. At the core of the system is a custom, wide field-of-view, fluorescence microscope that images arrays of microwells containing single molecules bound to magnetic beads. A consumable disc containing 24 microstructure arrays was developed previously in collaboration with Sony DADC. The system cadence requirements, array dimensions, and requirement to detect single molecules presented significant optical challenges. Specifically, the wide field-of-view needed to image the entire array resulted in the need for a custom objective lens. Additionally, cost considerations for the system required a custom solution that leveraged the image processing capabilities. This paper will discuss the design considerations and resultant optical architecture that has enabled the development of an automated digital ELISA platform.

Brownian dynamics simulations with stiff finitely extensible nonlinear elastic-Fraenkel springs as approximations to rods in bead-rod models.

PubMed

Hsieh, Chih-Chen; Jain, Semant; Larson, Ronald G

2006-01-28

A very stiff finitely extensible nonlinear elastic (FENE)-Fraenkel spring is proposed to replace the rigid rod in the bead-rod model. This allows the adoption of a fast predictor-corrector method so that large time steps can be taken in Brownian dynamics (BD) simulations without over- or understretching the stiff springs. In contrast to the simple bead-rod model, BD simulations with beads and FENE-Fraenkel (FF) springs yield a random-walk configuration at equilibrium. We compare the simulation results of the free-draining bead-FF-spring model with those for the bead-rod model in relaxation, start-up of uniaxial extensional, and simple shear flows, and find that both methods generate nearly identical results. The computational cost per time step for a free-draining BD simulation with the proposed bead-FF-spring model is about twice as high as the traditional bead-rod model with the midpoint algorithm of Liu [J. Chem. Phys. 90, 5826 (1989)]. Nevertheless, computations with the bead-FF-spring model are as efficient as those with the bead-rod model in extensional flow because the former allows larger time steps. Moreover, the Brownian contribution to the stress for the bead-FF-spring model is isotropic and therefore simplifies the calculation of the polymer stresses. In addition, hydrodynamic interaction can more easily be incorporated into the bead-FF-spring model than into the bead-rod model since the metric force arising from the non-Cartesian coordinates used in bead-rod simulations is absent from bead-spring simulations. Finally, with our newly developed bead-FF-spring model, existing computer codes for the bead-spring models can trivially be converted to ones for effective bead-rod simulations merely by replacing the usual FENE or Cohen spring law with a FENE-Fraenkel law, and this convertibility provides a very convenient way to perform multiscale BD simulations.

Brownian dynamics simulations with stiff finitely extensible nonlinear elastic-Fraenkel springs as approximations to rods in bead-rod models

NASA Astrophysics Data System (ADS)

Hsieh, Chih-Chen; Jain, Semant; Larson, Ronald G.

2006-01-01

A very stiff finitely extensible nonlinear elastic (FENE)-Fraenkel spring is proposed to replace the rigid rod in the bead-rod model. This allows the adoption of a fast predictor-corrector method so that large time steps can be taken in Brownian dynamics (BD) simulations without over- or understretching the stiff springs. In contrast to the simple bead-rod model, BD simulations with beads and FENE-Fraenkel (FF) springs yield a random-walk configuration at equilibrium. We compare the simulation results of the free-draining bead-FF-spring model with those for the bead-rod model in relaxation, start-up of uniaxial extensional, and simple shear flows, and find that both methods generate nearly identical results. The computational cost per time step for a free-draining BD simulation with the proposed bead-FF-spring model is about twice as high as the traditional bead-rod model with the midpoint algorithm of Liu [J. Chem. Phys. 90, 5826 (1989)]. Nevertheless, computations with the bead-FF-spring model are as efficient as those with the bead-rod model in extensional flow because the former allows larger time steps. Moreover, the Brownian contribution to the stress for the bead-FF-spring model is isotropic and therefore simplifies the calculation of the polymer stresses. In addition, hydrodynamic interaction can more easily be incorporated into the bead-FF-spring model than into the bead-rod model since the metric force arising from the non-Cartesian coordinates used in bead-rod simulations is absent from bead-spring simulations. Finally, with our newly developed bead-FF-spring model, existing computer codes for the bead-spring models can trivially be converted to ones for effective bead-rod simulations merely by replacing the usual FENE or Cohen spring law with a FENE-Fraenkel law, and this convertibility provides a very convenient way to perform multiscale BD simulations.

Modeling of weld bead geometry for rapid manufacturing by robotic GMAW

NASA Astrophysics Data System (ADS)

Yang, Tao; Xiong, Jun; Chen, Hui; Chen, Yong

2015-03-01

Weld-based rapid prototyping (RP) has shown great promises for fabricating 3D complex parts. During the layered deposition of forming metallic parts with robotic gas metal arc welding, the geometry of a single weld bead has an important influence on surface finish quality, layer thickness and dimensional accuracy of the deposited layer. In order to obtain accurate, predictable and controllable bead geometry, it is essential to understand the relationships between the process variables with the bead geometry (bead width, bead height and ratio of bead width to bead height). This paper highlights an experimental study carried out to develop mathematical models to predict deposited bead geometry through the quadratic general rotary unitized design. The adequacy and significance of the models were verified via the analysis of variance. Complicated cause-effect relationships between the process parameters and the bead geometry were revealed. Results show that the developed models can be applied to predict the desired bead geometry with great accuracy in layered deposition with accordance to the slicing process of RP.

In situ magnetic separation of antibody fragments from Escherichia coli in complex media

PubMed Central

2013-01-01

Background In situ magnetic separation (ISMS) has emerged as a powerful tool to overcome process constraints such as product degradation or inhibition of target production. In the present work, an integrated ISMS process was established for the production of his-tagged single chain fragment variable (scFv) D1.3 antibodies (“D1.3”) produced by E. coli in complex media. This study investigates the impact of ISMS on the overall product yield as well as its biocompatibility with the bioprocess when metal-chelate and triazine-functionalized magnetic beads were used. Results Both particle systems are well suited for separation of D1.3 during cultivation. While the triazine beads did not negatively impact the bioprocess, the application of metal-chelate particles caused leakage of divalent copper ions in the medium. After the ISMS step, elevated copper concentrations above 120 mg/L in the medium negatively influenced D1.3 production. Due to the stable nature of the model protein scFv D1.3 in the biosuspension, the application of ISMS could not increase the overall D1.3 yield as was shown by simulation and experiments. Conclusions We could demonstrate that triazine-functionalized beads are a suitable low-cost alternative to selectively adsorb D1.3 fragments, and measured maximum loads of 0.08 g D1.3 per g of beads. Although copper-loaded metal-chelate beads did adsorb his-tagged D1.3 well during cultivation, this particle system must be optimized by minimizing metal leakage from the beads in order to avoid negative inhibitory effects on growth of the microorganisms and target production. Hereby, other types of metal chelate complexes should be tested to demonstrate biocompatibility. Such optimized particle systems can be regarded as ISMS platform technology, especially for the production of antibodies and their fragments with low stability in the medium. The proposed model can be applied to design future ISMS experiments in order to maximize the overall product yield while the amount of particles being used is minimized as well as the number of required ISMS steps. PMID:23688064

Directed differentiation of embryonic stem cells using a bead-based combinatorial screening method.

PubMed

Tarunina, Marina; Hernandez, Diana; Johnson, Christopher J; Rybtsov, Stanislav; Ramathas, Vidya; Jeyakumar, Mylvaganam; Watson, Thomas; Hook, Lilian; Medvinsky, Alexander; Mason, Chris; Choo, Yen

2014-01-01

We have developed a rapid, bead-based combinatorial screening method to determine optimal combinations of variables that direct stem cell differentiation to produce known or novel cell types having pre-determined characteristics. Here we describe three experiments comprising stepwise exposure of mouse or human embryonic cells to 10,000 combinations of serum-free differentiation media, through which we discovered multiple novel, efficient and robust protocols to generate a number of specific hematopoietic and neural lineages. We further demonstrate that the technology can be used to optimize existing protocols in order to substitute costly growth factors with bioactive small molecules and/or increase cell yield, and to identify in vitro conditions for the production of rare developmental intermediates such as an embryonic lymphoid progenitor cell that has not previously been reported.

Formulation and characterization of a compacted multiparticulate system for modified release of water-soluble drugs--part 1--acetaminophen.

PubMed

Cantor, Stuart L; Hoag, Stephen W; Augsburger, Larry L

2009-03-01

The aim of this study was to characterize and evaluate a modified release, multiparticulate tablet formulation consisting of placebo beads and drug-loaded beads. Acetaminophen (APAP) bead formulations containing ethylcellulose (EC) from 40-60% and placebo beads containing 30% calcium silicate and prepared using 0-20% alcohol were developed using extrusion-spheronization and studied using a central composite experimental design. Particle size and true density of beads were measured. Segregation testing was performed using the novel ASTM D6940-04 method on a 50:50 blend of uncoated APAP beads (60%EC) : calcium silicate placebo beads (10% alcohol). Tablets were prepared using an instrumented Stokes-B2 rotary tablet press and evaluated for crushing strength and dissolution rate. Compared with drug beads (60%EC), placebo beads (10% alcohol) were smaller but had higher true densities: 864.8 mum and 1.27 g/cm(3), and 787.1 mum and 1.73 g/cm(3), respectively. Segregation testing revealed that there was approximately a 20% difference in drug content (as measured by the coefficient of variation) between initial and final blend samples. Although calcium silicate-based placebo beads were shown to be ineffective cushioning agents in blends with Surelease(R)-coated APAP beads, they were found to be very compactibile when used alone and gave tablet crushing strength values between 14 and 17 kP. The EC in the APAP bead matrix minimally suppressed the drug release from uncoated beads (t(100%) = 2 h). However, while tablets containing placebo beads reformulated with glycerol monostearate (GMS) showed a slower release rate (t(60%)= 5 h) compared with calcium silicate-based placebos, some coating damage ( approximately 30%) still occurred on compression as release was faster than coated APAP beads alone. While tablets containing coated drug beads can be produced with practical crushing strengths (>8 kP) and low compression pressures (10-35 MPa), dissolution studies revealed that calcium silicate-based placebos are ineffective as cushioning agents. Blend segregation was likely observed due to the particle size and the density differences between APAP beads and calcium silicate-based placebo beads; placebo bead percolation can perhaps be minimized by increasing their size during the extrusion-spheronization process. The GMS- based placebos offer greater promise as cushioning agents for compacted, coated drug beads; however, this requires an optimized compression pressure range and drug bead : placebo bead ratio (i.e., 50:50).

Microscopic Examination of Chitosan Polyphosphate Beads with Entrapped Spores of the Biocontrol Agent, Streptomyces melanosporofaciens EF-76

NASA Astrophysics Data System (ADS)

Jobin, Guy; Grondin, Gilles; Couture, Geneviève; Beaulieu, Carole

2005-04-01

Spores of the biocontrol agent, Streptomyces melanosporofaciens EF-76, were entrapped by complex coacervation in beads composed of a macromolecular complex (MC) of chitosan and polyphosphate. A proportion of spores entrapped in beads survived the entrapment procedure as shown by treating spores from chitosan beads with a dye allowing the differentiation of live and dead cells. The spore-loaded chitosan beads could be digested by a chitosanase, suggesting that, once introduced in soil, the beads would be degraded to release the biocontrol agent. Spore-loaded beads were examined by optical and scanning electron microscopy because the release of the biological agent depends on the spore distribution in the chitosan beads. The microscopic examination revealed that the beads had a porous surface and contained a network of inner microfibrils. Spores were entrapped in both the chitosan microfibrils and the bead lacuna.

Relaxation dynamics of internal segments of DNA chains in nanochannels

NASA Astrophysics Data System (ADS)

Jain, Aashish; Muralidhar, Abhiram; Dorfman, Kevin; Dorfman Group Team

We will present relaxation dynamics of internal segments of a DNA chain confined in nanochannel. The results have direct application in genome mapping technology, where long DNA molecules containing sequence-specific fluorescent probes are passed through an array of nanochannels to linearize them, and then the distances between these probes (the so-called ``DNA barcode'') are measured. The relaxation dynamics of internal segments set the experimental error due to dynamic fluctuations. We developed a multi-scale simulation algorithm, combining a Pruned-Enriched Rosenbluth Method (PERM) simulation of a discrete wormlike chain model with hard spheres with Brownian dynamics (BD) simulations of a bead-spring chain. Realistic parameters such as the bead friction coefficient and spring force law parameters are obtained from PERM simulations and then mapped onto the bead-spring model. The BD simulations are carried out to obtain the extension autocorrelation functions of various segments, which furnish their relaxation times. Interestingly, we find that (i) corner segments relax faster than the center segments and (ii) relaxation times of corner segments do not depend on the contour length of DNA chain, whereas the relaxation times of center segments increase linearly with DNA chain size.

DC bead: in vitro characterization of a drug-delivery device for transarterial chemoembolization.

PubMed

Lewis, Andrew L; Gonzalez, M Victoria; Lloyd, Andrew W; Hall, Brenda; Tang, Yiqing; Willis, Sean L; Leppard, Simon W; Wolfenden, Laura C; Palmer, Rosemary R; Stratford, Peter W

2006-02-01

The purpose of this investigation is to present the in vitro characterization and detailed drug-loading procedure for DC Bead, a microsphere product that can be loaded with chemotherapeutic agents for embolization. DC Bead is an embolic microsphere product that is capable of being loaded with anthracycline drugs such as doxorubicin just before administration in a transarterial chemoembolization (TACE) procedure. Beads can be loaded from solutions prepared from doxorubicin powder or the doxorubicin HCl formulation. In this evaluation, bead sizes were measured by optical microscopy with video imaging. Gravimetric analysis demonstrated the effect of drug loading on bead water content, and its consequent impact on bead compressibility was determined. The subsequent deliverability of the beads was assessed by mixing the beads with contrast medium and saline solution and passing the beads through an appropriately sized microcatheter. A T-cell apparatus was used to monitor the in vitro elution of the drug from the beads over a period of 24 hours in various elution media. DC Bead spheres could be easily loaded with doxorubicin to a recommended level of 25 mg/mL of hydrated beads by immersion of the beads in the drug solution for 10-120 minutes depending on microsphere size. Other commercial embolic microspheres were shown not to load doxorubicin to the same extent or release it in the same fashion and were considered unsuitable for local drug delivery. Maximum theoretic capacity for DC Bead was approximately 45 mg/mL. Increase in doxorubicin loading resulted in a concomitant decrease in water content and consequential increase in bead resistance to compression force. Drug loading also resulted in a decrease in the average size of the beads, which was dependent on bead size and drug dose. This did not impact bead delivery at any drug loading level to a maximum of 37.5 mg/mL. Beads 100-700 microm in size could be delivered through 2.7-F microcatheters, whereas the 700-900-microm range required 3-F catheters. Modeling of the kinetics of drug elution from the beads in vitro at a loading dose of 25 mg/mL yielded calculated half-lives of 150 hours for the 100-300-microm range to a maximum of 1,730 hours for the 700-900-microm size range, which was dependent on the ionic strength of the elution medium. For comparison, there was a rapid loss of drug from an unstable Lipiodol emulsion with a half-life of approximately 1 hour. DC Bead can be loaded with doxorubicin to provide an accurate dosage of drug per unit volume of beads. Drug elution is dependent on ion exchange with the surrounding environment and is controlled and sustained, unlike the rapid separation of the drug from Lipiodol. Drug loading has no impact on the handling and deliverability of the beads, making them suitable for superselective TACE.

Dual stimuli-responsive smart beads that allow "on-off" manipulation of cancer cells.

PubMed

Kim, Young-Jin; Kim, Soo Hyeon; Fujii, Teruo; Matsunaga, Yukiko T

2016-06-24

Temperature- and electric field-responsive polymer-conjugated polystyrene beads, termed smart beads, are designed to isolate cancer cells. In smart beads, the reversible "on-off" antigen-antibody reaction and dielectrophoresis force on an electrode are accomplished to realize "on-off" remote manipulation of smart beads and cancer cells. Both the zeta-potential and the hydrodynamic diameter of the smart beads are sensitive to temperature, allowing "on-off" reversible capture and release of cancer cells. Cancer cell-captured smart beads are then localized on electrodes by applying an electrical signal.

An Attempt to Shorten Loading Time of Epirubicin into DC Beads® Using Vibration and a Sieve.

PubMed

Sonoda, Akinaga; Nitta, Norihisa; Yamamoto, Takefumi; Tomozawa, Yuki; Ohta, Shinichi; Watanabe, Shobu; Murata, Kiyoshi

2017-04-01

We investigated the possibility of shortening the time required for loading epirubicin into calibrated polyvinyl alcohol-based hydrogel beads (DC Beads ® ) to be used for transarterial chemoembolization. After separating the beads suspended in phosphate-buffered saline (PBS) solution by the use of a sieve (clearance 75 µm), epirubicin hydrochloride (EH) was loaded for 20, 30, or 60 s under vibration into DC beads. The EH loading rate into conventionally prepared (control) beads, i.e., beads loaded for 30 min without vibration, and vibration-loaded beads were calculated from the residual EH concentration in the bead-depleted EH solution. The amount of EH eluted from conventionally and vibration-loaded samples into a PBS solution (pH 7.0) was measured at 15 and 30 min and 1, 2, 6, 12, and 24 h. We also recorded the inhibitory effect of the PBS solution on the loading time. Using frozen sections, the EH load in the beads was evaluated visually under a fluorescence microscope. Spectrophotometry (495 nm) showed that the loading rate was 98.98 ± 0.34, 99.02 ± 0.32, and 99.50 ± 0.11 % with 20-, 30-, and 60-s vibration, respectively. The eluted rate was statistically similar between vibration- and statically loaded (control) beads. The PBS solution hampered EH loading into the beads. Visually, the distribution of EH in conventionally and vibration-loaded DC beads was similar. The use of vibration and the removal of PBS solution when epirubicin hydrochloride was loaded into DC beads dramatically shortened the loading time of epirubicin hydrochloride into DC beads.

Rare Earth Adsorption and Desorption with PEGDA Beads

DOE Data Explorer

Jiao, Yongqin; Brewer, Aaron; Park, Dan

2017-03-01

We synthesized PEGDA polymer hydrogel beads for cell embedding and compared REE biosorption with these beads via a gravity-driven flow through setup. One way to set up a flow through system is by cell encapsulation into polymer beads with a column setup similar to that used in the chromatography industry. To achieve this, we tested PEGDA for cell encapsulation, and tested REE biosorption under both batch mode and a follow through setup based on gravity . For making the cell embedded polymer beads, we used a fluidic device by which homogenous spherical particles of 0.5 to1 mm in diameter were synthesized. The beads are made relatively quickly, and the size of the beads can be controlled. PEGDA beads were polymerized by UV. Tb adsorption experiment was performed with beads with or without cells embedded.

Scaling, clustering and avalanches for steel beads in an external magnetic field

NASA Astrophysics Data System (ADS)

Marquinez, Alyse; Thvedt, Ingrid; Lehman, S. Y.; Jacobs, D. T.

2011-03-01

We investigated avalanches using uniform 3mm steel spheres (``beads'') dropped onto a conical bead pile within a uniform magnetic field. The bead pile is built by pouring beads onto a circular base where the bottom layer of beads had been glued randomly. Beads are then individually dropped from a fixed height after which the pile is massed. This process is repeated for thousands of bead drops. By measuring the number of avalanches of a given size that occurred during the experiment, the resulting avalanche size distribution was compared to a power law description as predicted by self-organized criticality. As the magnetic field intensity increased, the beads clustered to give a larger angle of repose and we measured the change in the avalanche size distribution. The moments of the distribution give a sensitive test of mean-field theory as the universality class for these bead piles. We acknowledge support from Research Corporation and NSF-REU grant DMR 0649112.

Preparation of ionic-crosslinked chitosan-based gel beads and effect of reaction conditions on drug release behaviors.

PubMed

Chen, Shilan; Liu, Mingzhu; Jin, Shuping; Wang, Bin

2008-02-12

Drug-loaded chitosan (CS) beads were prepared under simple and mild condition using trisodium citrate as ionic crosslinker. The beads were further coated with poly(methacrylic acid) (PMAA) by dipping the beads in PMAA aqueous solution. The surface and cross-section morphology of these beads were observed by scanning electron microscopy and the observation showed that the coating beads had core-shell structure. In vitro release of model drug from these beads obtained under different reaction conditions was investigated in buffer medium (pH 1.8). The results showed that the rapid drug release was restrained by PMAA coating and the optimum conditions for preparing CS-based drug-loaded beads were decided through the effect of reaction conditions on the drug release behaviors. In addition, the drug release mechanism of CS-based drug-loaded beads was analyzed by Peppa's potential equation. According to this study, the ionic-crosslinked CS beads coated by PMAA could serve as suitable candidate for drug site-specific carrier in stomach.

Prion extraction methods: comparison of bead beating, ultrasonic disruption and repeated freeze-thaw methodologies for the recovery of functional renilla-prion fusion protein from bacteria

USDA-ARS?s Scientific Manuscript database

Molecular DNA technology allows for production of mammalian proteins in bacteria at sufficient quantities for downstream use and analysis. Variation in design and engineering of DNA expression vectors imparts selective alterations resulting in the generation of fusion proteins with intrinsic report...

Bacteriophage-based rapid and sensitive detection of Escherichia coli O157:H7 isolates from ground beef

USDA-ARS?s Scientific Manuscript database

We investigated efficacy of bacteriophage-based detection technology to detect Escherichia coli O157:H7 from ground beef. The assay involved 8 h enrichment of cold stressed beef samples in presence of antimicrobials followed by capture of the pathogen on O157:H7-specific immunomagnetic beads and sp...

Radiotherapy Measurements with a Deoxyribonucleic Acid Doublestrand-Break Dosimeter

NASA Astrophysics Data System (ADS)

Obeidat, Mohammad Ali

Many types of dosimeters are used in the clinic to measure radiation dose for therapy but none of them directly measures the biological effect of this dose. The overall purpose of this work was to develop a dosimeter that measures biological damage in the form of double-strand breaks to deoxyribonucleic acid. This dosimeter could provide a more biologically relevant measure of radiation damage than the currently utilized dosimeters. A pair of oligonucleotides was designed to fabricate this dosimeter. One is labeled with a 5'-end biotin and the other with a 5'-end 6 Fluorescein amidite (fluorescent dye excited at 495?nanometer, with a peak emission at 520 nanometer). These were designed to adhere to certain locations on the pRS316 vector and serve as the primers for polymerase chain reactions. The end product of this reaction is a 4 kilo-base pair double strands deoxyribonucleic acid fragment with biotin on one end and 6 Fluorescein amidite oligonucleotide on the other attached to streptavidin beads. The biotin end connects the double strands deoxyribonucleic acid to the streptavidin bead. These bead-connected double strands deoxyribonucleic acid were suspended in 50 microliter of phosphate-buffered saline and placed into a tube for irradiation. Following irradiation of the deoxyribonucleic acid dosimeter, we take advantage of the magnetic properties of the streptavidin bead by placing our sample microtube against a magnet. The magnetic field pulls the streptavidin beads against the side of the tube. If a double-strand-break has occurred for a double strands deoxyribonucleic acid, the fluorescein end of the double strands deoxyribonucleic acid becomes free and is no longer attached to the bead or held against the side of the microtube. The free fluorescein following a double-strand-break in double strands deoxyribonucleic acid is referred to here as supernatant. The supernatant is extracted and placed in another microtube, while the unbroken double strands deoxyribonucleic acid remain attached to the beads and stay in the microtube (Fig. 4). Those beads were re-suspended with 50 microliter of phosphate-buffered saline again (called beads), then we placed both supernatant and beads in a reader microplate and we read the fluorescence signal for both with a fluorescence reader (BioTek Synergy 2). These beads and supernatant fluorescence signals are denoted by B and S, respectively. The relative amount of supernatant fluorescence counts is proportional to the probability of a double-strand-break. The probability of double-strand-break was calculated with the following equation: (S-BG)/(S+B-2BG) (1). where S was the supernatant fluorescence intensity (related to the number of double strands deoxyribonucleic acid with double-strand breaks), B was the re-suspended beads fluorescence intensity (related to the number of double strands deoxyribonucleic acid without double-strand breaks), and BG was the phosphate-buffered saline fluorescence intensity (related to the background signal). There are two advantages that this type of dosimeter has over the gel separation technique. First, it is important to irradiate deoxyribonucleic acid in a solution that has similar osmolarity and ion concentrations to that in a human, such as phosphate-buffered saline. A gel dosimeter would require a transfer to gel to separate deoxyribonucleic acid, whereas our dosimeter can be separated in this solution. Currently, we use pipettes to manually perform this separation, but this step could be automated. Second, the magnetic deoxyribonucleic acid separation technique is much faster than that for gel electrophoresis. Calibration of radiotherapy equipment isn't something that happens in national science laboratories, with only world-leading experts. This is something that happens locally at every cancer clinic, with physicists that do not have the luxury of focusing solely on this one measurement. For this reason, ease of use is critical for this type of technology. (Abstract shortened by ProQuest.).

Charging of multiple interacting particles by contact electrification.

PubMed

Soh, Siowling; Liu, Helena; Cademartiri, Rebecca; Yoon, Hyo Jae; Whitesides, George M

2014-09-24

Many processes involve the movement of a disordered collection of small particles (e.g., powders, grain, dust, and granular foods). These particles move chaotically, interact randomly among themselves, and gain electrical charge by contact electrification. Understanding the mechanisms of contact electrification of multiple interacting particles has been challenging, in part due to the complex movement and interactions of the particles. To examine the processes contributing to contact electrification at the level of single particles, a system was constructed in which an array of millimeter-sized polymeric beads of different materials were agitated on a dish. The dish was filled almost completely with beads, such that beads did not exchange positions. At the same time, during agitation, there was sufficient space for collisions with neighboring beads. The charge of the beads was measured individually after agitation. Results of systematic variations in the organization and composition of the interacting beads showed that three mechanisms determined the steady-state charge of the beads: (i) contact electrification (charging of beads of different materials), (ii) contact de-electrification (discharging of beads of the same charge polarity to the atmosphere), and (iii) a long-range influence across beads not in contact with one another (occurring, plausibly, by diffusion of charge from a bead with a higher charge to a bead with a lower charge of the same polarity).

Integration of Magnetic Bead-Based Cell Selection into Complex Isolations

PubMed Central

2018-01-01

Magnetic bead-based analyte capture has emerged as a ubiquitous method in cell isolation, enabling the highly specific capture of target populations through simple magnetic manipulation. To date, no “one-size fits all” magnetic bead has been widely adopted leading to an overwhelming number of commercial beads. Ultimately, the ideal bead is one that not only facilitates cell isolation but also proves compatible with the widest range of downstream applications and analytic endpoints. Despite the diverse offering of sizes, coatings, and conjugation chemistries, few studies exist to benchmark the performance characteristics of different commercially available beads; importantly, these bead characteristics ultimately determine the ability of a bead to integrate into the user’s assay. In this report, we evaluate bead-based cell isolation considerations, approaches, and results across a subset of commercially available magnetic beads (Dynabeads FlowComps, Dynabeads CELLection, GE Healthcare Sera-Mag SpeedBeads streptavidin-blocked magnetic particles, Dynabeads M-270s, Dynabeads M-280s) to compare and contrast both capture-specific traits (i.e., purity, capture efficacy, and contaminant isolations) and endpoint compatibility (i.e., protein localization, fluorescence imaging, and nucleic acid extraction). We identify specific advantages and contexts of use in which distinct bead products may facilitate experimental goals and integrate into downstream applications. PMID:29732449

Controlling the size of alginate gel beads by use of a high electrostatic potential.

PubMed

Klokk, T I; Melvik, J E

2002-01-01

The effect of several parameters on the size of alginate beads produced by use of an electrostatic potential bead generator was examined. Parameters studied included needle diameter, electrostatic potential, alginate solution flow rate, gelling ion concentration and alginate concentration and viscosity, as well as alginate composition. Bead size was found to decrease with increasing electrostatic potential, but only down to a certain level. Minimum bead size was reached at between 2-4 kV/cm for the needles tested. The smallest alginate beads produced (using a needle with inner diameter 0.18 mm) had a mean diameter of approximately 300 microm. Bead size was also found to be dependent upon the flow rate of the fed alginate solution. Increasing the gelling ion concentration resulted in a moderate decrease in bead size. The concentration and viscosity of the alginate solution also had an effect on bead size as demonstrated by an increased bead diameter when the concentration or viscosity was increased. This effect was primarily an effect of the viscosity properties of the solution, which led to changes in the rate of droplet formation in the bead generator. Lowering the flow rate of the alginate solution could partly compensate for the increase in bead size with increased viscosity. For a constant droplet size, alginates with a low G block content (F(GG) approximately 0.20) resulted in approximately 30% smaller beads than alginates with a high G block content (F(GG) approximately 0.60). This is explained as a result of differences in the shrinking properties of the beads.

Elution of Clindamycin and Enrofloxacin From Calcium Sulfate Hemihydrate Beads In Vitro.

PubMed

Phillips, Heidi; Boothe, Dawn M; Bennett, R Avery

2015-11-01

To compare the in vitro elution characteristics of clindamycin and enrofloxacin from calcium sulfate hemihydrate beads containing a single antibiotic, both antibiotics, and each antibiotic incubated in the same eluent well. Experimental in vitro study. Calcium sulfate hemihydrate beads were formed by mixing with clindamycin and/or enrofloxacin to create 4 study groups: (1) 160 mg clindamycin/10 beads; (2) 160 mg enrofloxacin/10 beads; (3) 160 mg clindamycin + 160 mg enrofloxacin/10 beads; and (4) 160 mg clindamycin/5 beads and 160 mg enrofloxacin/5 beads. Chains of beads were formed in triplicate and placed in 5 mL phosphate buffered saline (PBS; pH 7.4 and room temperature) with constant agitation. Antibiotic-conditioned PBS was sampled at 14 time points from 1 hour to 30 days. Clindamycin and enrofloxacin concentrations in PBS were determined using high-performance liquid chromatography. Eluent concentrations from clindamycin-impregnated beads failed to remain sufficiently above minimum inhibitory concentration (MIC) for common infecting bacteria over the study period. Enrofloxacin eluent concentrations remained sufficiently above MIC for common wound pathogens of dogs and cats and demonstrated an atypical biphasic release pattern. No significant differences in elution occurred as a result of copolymerization of the antibiotics into a single bead or from individual beads co-eluting in the same eluent well. Clindamycin-impregnated beads cannot be recommended for treatment of infection at the studied doses; however, use of enrofloxacin-impregnated beads may be justified when susceptible bacteria are cultured. © Copyright 2015 by The American College of Veterinary Surgeons.

Digital microfluidics-enabled single-molecule detection by printing and sealing single magnetic beads in femtoliter droplets.

PubMed

Witters, Daan; Knez, Karel; Ceyssens, Frederik; Puers, Robert; Lammertyn, Jeroen

2013-06-07

Digital microfluidics is introduced as a novel platform with unique advantages for performing single-molecule detection. We demonstrate how superparamagnetic beads, used for capturing single protein molecules, can be printed with unprecedentedly high loading efficiency and single bead resolution on an electrowetting-on-dielectric-based digital microfluidic chip by micropatterning the Teflon-AF surface of the device. By transporting droplets containing suspended superparamagnetic beads over a hydrophilic-in-hydrophobic micropatterned Teflon-AF surface, single beads are trapped inside the hydrophilic microwells due to their selective wettability and tailored dimensions. Digital microfluidics presents the following advantages for printing and sealing magnetic beads for single-molecule detection: (i) droplets containing suspended beads can be transported back and forth over the array of hydrophilic microwells to obtain high loading efficiencies of microwells with single beads, (ii) the use of hydrophilic-in-hydrophobic patterns permits the use of a magnet to speed up the bead transfer process to the wells, while the receding droplet meniscus removes excess beads off the chip surface and thereby shortens the bead patterning time, and (iii) reagents can be transported over the printed beads multiple times, while capillary forces and a magnet hold the printed beads in place. High loading efficiencies (98% with a CV of 0.9%) of single beads in microwells were obtained by transporting droplets of suspended beads over the array 10 times in less than 1 min, which is much higher than previously reported methods (40-60%), while the total surface area needed for performing single-molecule detection can be decreased. The performance of the device was demonstrated by fluorescent detection of the presence of the biotinylated enzyme β-galactosidase on streptavidin-coated beads with a linear dynamic range of 4 orders of magnitude ranging from 10 aM to 90 fM.

Broad adsorption of sepsis-related PAMP and DAMP molecules, mycotoxins, and cytokines from whole blood using CytoSorb® sorbent porous polymer beads

PubMed Central

Ruggeberg, Karl-Gustav; O’Sullivan, Pamela; Guliashvili, Tamaz; Scheirer, Andrew R.; Golobish, Thomas D.; Capponi, Vincent J.; Chan, Phillip P.

2018-01-01

Objective Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. In sepsis and septic shock, pathogen-associated molecular pattern molecules (PAMPS), such as bacterial exotoxins, cause direct cellular damage and/or trigger an immune response in the host often leading to excessive cytokine production, a maladaptive systemic inflammatory response syndrome response (SIRS), and tissue damage that releases DAMPs, such as activated complement and HMGB-1, into the bloodstream causing further organ injury. Cytokine reduction using extracorporeal blood filtration has been correlated with improvement in survival and clinical outcomes in experimental studies and clinical reports, but the ability of this technology to reduce a broader range of inflammatory mediators has not been well-described. This study quantifies the size-selective adsorption of a wide range of sepsis-related inflammatory bacterial and fungal PAMPs, DAMPs and cytokines, in a single compartment, in vitro whole blood recirculation system. Measurements and main results Purified proteins were added to whole blood at clinically relevant concentrations and recirculated through a device filled with CytoSorb® hemoadsorbent polymer beads (CytoSorbents Corporation, USA) or control (no bead) device in vitro. Except for the TNF-α trimer, hemoadsorption through porous polymer bead devices reduced the levels of a broad spectrum of cytokines, DAMPS, PAMPS and mycotoxins by more than 50 percent. Conclusions This study demonstrates that CytoSorb® hemoadsorbent polymer beads efficiently remove a broad spectrum of toxic PAMPS and DAMPS from blood providing an additional means of reducing the uncontrolled inflammatory cascade that contributes to a maladaptive SIRS response, organ dysfunction and death in patients with a broad range of life-threatening inflammatory conditions such as sepsis, toxic shock syndrome, necrotizing fasciitis, and other severe inflammatory conditions. PMID:29370247

Method of synthesizing bulk transition metal carbide, nitride and phosphide catalysts

DOEpatents

Choi, Jae Soon; Armstrong, Beth L; Schwartz, Viviane

2015-04-21

A method for synthesizing catalyst beads of bulk transmission metal carbides, nitrides and phosphides is provided. The method includes providing an aqueous suspension of transition metal oxide particles in a gel forming base, dropping the suspension into an aqueous solution to form a gel bead matrix, heating the bead to remove the binder, and carburizing, nitriding or phosphiding the bead to form a transition metal carbide, nitride, or phosphide catalyst bead. The method can be tuned for control of porosity, mechanical strength, and dopant content of the beads. The produced catalyst beads are catalytically active, mechanically robust, and suitable for packed-bed reactor applications. The produced catalyst beads are suitable for biomass conversion, petrochemistry, petroleum refining, electrocatalysis, and other applications.

Optimization and Prediction of Angular Distortion and Weldment Characteristics of TIG Square Butt Joints

NASA Astrophysics Data System (ADS)

Narang, H. K.; Mahapatra, M. M.; Jha, P. K.; Biswas, P.

2014-05-01

Autogenous arc welds with minimum upper weld bead depression and lower weld bead bulging are desired as such welds do not require a second welding pass for filling up the upper bead depressions (UBDs) and characterized with minimum angular distortion. The present paper describes optimization and prediction of angular distortion and weldment characteristics such as upper weld bead depression and lower weld bead bulging of TIG-welded structural steel square butt joints. Full factorial design of experiment was utilized for selecting the combinations of welding process parameter to produce the square butts. A mathematical model was developed to establish the relationship between TIG welding process parameters and responses such as upper bead width, lower bead width, UBD, lower bead height (bulging), weld cross-sectional area, and angular distortions. The optimal welding condition to minimize UBD and lower bead bulging of the TIG butt joints was identified.

A Wide-Field Fluorescence Microscope Extension for Ultrafast Screening of One-Bead One-Compound Libraries Using a Spectral Image Subtraction Approach.

PubMed

Heusermann, Wolf; Ludin, Beat; Pham, Nhan T; Auer, Manfred; Weidemann, Thomas; Hintersteiner, Martin

2016-05-09

The increasing involvement of academic institutions and biotech companies in drug discovery calls for cost-effective methods to identify new bioactive molecules. Affinity-based on-bead screening of combinatorial one-bead one-compound libraries combines a split-mix synthesis design with a simple protein binding assay operating directly at the bead matrix. However, one bottleneck for academic scale on-bead screening is the unavailability of a cheap, automated, and robust screening platform that still provides a quantitative signal related to the amount of target protein binding to individual beads for hit bead ranking. Wide-field fluorescence microscopy has long been considered unsuitable due to significant broad spectrum autofluorescence of the library beads in conjunction with low detection sensitivity. Herein, we demonstrate how such a standard microscope equipped with LED-based excitation and a modern CMOS camera can be successfully used for selecting hit beads. We show that the autofluorescence issue can be overcome by an optical image subtraction approach that yields excellent signal-to-noise ratios for the detection of bead-associated target proteins. A polymer capillary attached to a semiautomated bead-picking device allows the operator to efficiently isolate individual hit beads in less than 20 s. The system can be used for ultrafast screening of >200,000 bead-bound compounds in 1.5 h, thereby making high-throughput screening accessible to a wider group within the scientific community.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sonoda, Akinaga, E-mail: akinagasonoda@yahoo.co.jp; Nitta, Norihisa; Yamamoto, Takefumi

PurposeWe investigated the possibility of shortening the time required for loading epirubicin into calibrated polyvinyl alcohol-based hydrogel beads (DC Beads{sup ®}) to be used for transarterial chemoembolization.MethodAfter separating the beads suspended in phosphate-buffered saline (PBS) solution by the use of a sieve (clearance 75 µm), epirubicin hydrochloride (EH) was loaded for 20, 30, or 60 s under vibration into DC beads. The EH loading rate into conventionally prepared (control) beads, i.e., beads loaded for 30 min without vibration, and vibration-loaded beads were calculated from the residual EH concentration in the bead-depleted EH solution. The amount of EH eluted from conventionally and vibration-loadedmore » samples into a PBS solution (pH 7.0) was measured at 15 and 30 min and 1, 2, 6, 12, and 24 h. We also recorded the inhibitory effect of the PBS solution on the loading time. Using frozen sections, the EH load in the beads was evaluated visually under a fluorescence microscope.ResultsSpectrophotometry (495 nm) showed that the loading rate was 98.98 ± 0.34, 99.02 ± 0.32, and 99.50 ± 0.11 % with 20-, 30-, and 60-s vibration, respectively. The eluted rate was statistically similar between vibration- and statically loaded (control) beads. The PBS solution hampered EH loading into the beads. Visually, the distribution of EH in conventionally and vibration-loaded DC beads was similar.DiscussionThe use of vibration and the removal of PBS solution when epirubicin hydrochloride was loaded into DC beads dramatically shortened the loading time of epirubicin hydrochloride into DC beads.« less

Stimulation of wound healing by positively charged dextran beads depends upon clustering of beads and cells in close proximity to the wound.

PubMed

Tawil, N J; Connors, D; Gies, D; Bennett, S; Gruskin, E; Mustoe, T

1999-01-01

We have previously shown that positively charged dextran (DEAE A25) increases wound breaking strength in linear incisions in rats and nonhuman primates at days 10-14 postwounding. In this article, we examined the cellular responses to different types of charged dextran beads (DEAE A50 and Cytodex-1) in culture studies and in rat incisional wounds. We show that Cytodex 1 and DEAE A50 beads also increased wound breaking strength in a rat linear incisional model. However, the increase was approximately 30-40% less than that observed in wounds treated with DEAE A25 beads. The main distinction between the three types of beads was the presence of bead clusters observed in tissue sections. Wounds treated with DEAE A25 beads formed distinct clusters while both Cytodex 1 and DEAE A50 beads clustered to a lesser extent or failed to cluster at all. We propose that the different types of charged dextran beads improve healing by promoting cell adhesion and encouraging proliferation in close proximity to the wound. We also hypothesize that the 30-40% improvement in wound breaking strength seen with DEAE A25 beads compared to other types of charged dextran beads (DEAE A50 and Cytodex-1) originates from the unique characteristic of DEAE A25 beads in forming cell-bead aggregates adjacent to the wounded area. This clustering, in turn, affects the distribution of cells infiltrating the wounded area (such as macrophages) during the healing process and, as a consequence, alters the distribution of matrix molecules and growth factors secreted by these cells.

Visualization and measurement of CO2 flooding in an artificial porous structure using micromodels

NASA Astrophysics Data System (ADS)

Park, Bogyeong; Wang, Sookyun; Um, Jeong-Gi; Lee, Minhee; Kim, Seon-Ok

2015-04-01

Geological CO2 sequestration is one of the most important technologies to mitigate greenhouse gas emission into the atmosphere by isolating great volumes of CO2 in deep geological formations. This novel storage option for CO2 involves injecting supercritical CO2 into porous formations saturated with pore fluid such as brine and initiate CO2 flooding with immiscible displacement. Despite of significant effects on macroscopic migration and distribution of injected CO2, however, only a limited information is available on wettability in microscopic scCO2-brine-mineral systems. In this study, a micromodel had been developed to improve our understanding of how CO2 flooding and residual characteristics of pore water are affected by the wettability in scCO2-water-glass bead systems. The micromodel (a transparent pore structure made of 1 mm diameter glass beads between two glass plates) in a high-pressure cell provided the opportunity to visualize spread of supercritical CO2 and displacement of pore water in high pressure and high temperature conditions. CO2 flooding followed by fingering migration and dewatering followed by formation of residual water were observed through a imaging system with a microscope. Measurement of contact angles of droplets of residual water on and between glass beads in a micromodel were conducted to estimate differential pressure between wetting and nonwetting fluids in a scCO2-water-glass bead system. The experimental observation results could provide important fundamental informations on capillary characteristics of reservoirs and caprocks for geological CO2 sequestration.

Visualization of CO2 flooding in an artificial porous structure using micromodels

NASA Astrophysics Data System (ADS)

Park, B.; Wang, S.; Lee, M.; Um, J. G.

2014-12-01

Geological CO2 sequestration is one of the most important technologies to mitigate greenhouse gas emission into the atmosphere by isolating great volumes of CO2 in deep geological formations. This novel storage option for CO2 involves injecting supercritical CO2 into porous formations saturated with pore fluid such as brine and initiate CO2 flooding with immiscible displacement. Despite of significant effects on macroscopic migration and distribution of injected CO2, however, only a limited information is available on wettability in microscopic scCO2-brine-mineral systems. In this study, a micromodel had been developed to improve our understanding of how CO2 flooding and residual characteristics of pore water are affected by the wettability in scCO2-water-glass bead systems. The micromodel (a transparent pore structure made of 0.5 mm diameter glass beads between two glass plates) in a high-pressure cell provided the opportunity to visualize spread of supercritical CO2 and displacement of pore water in high pressure and high temperature conditions. CO2 flooding followed by fingering migration and dewatering followed by formation of residual water were observed through a imaging system with a microscope. Measurement of contact angles of droplets of residual water on and between glass beads in a micromodel were conducted to estimate differential pressure between wetting and nonwetting fluids in a scCO2-water-glass bead system. The experimental observation results could provide important fundamental informations on capillary characteristics of reservoirs and caprocks for geological CO2 sequestration.

Electric field directed assembly of high-density microbead arrays†

PubMed Central

Barbee, Kristopher D.; Hsiao, Alexander P.; Heller, Michael J.; Huang, Xiaohua

2010-01-01

We report a method for rapid, electric field directed assembly of high-density protein-conjugated microbead arrays. Photolithography is used to fabricate an array of micron to sub-micron-scale wells in an epoxy-based photoresist on a silicon wafer coated with a thin gold film, which serves as the primary electrode. A thin gasket is used to form a microfluidic chamber between the wafer and a glass coverslip coated with indium-tin oxide, which serves as the counter electrode. Streptavidin-conjugated microbeads suspended in a low conductance buffer are introduced into the chamber and directed into the wells via electrophoresis by applying a series of low voltage electrical pulses across the electrodes. Hundreds of millions of microbeads can be permanently assembled on these arrays in as little as 30 seconds and the process can be monitored in real time using epifluorescence microscopy. The binding of the microbeads to the gold film is robust and occurs through electrochemically induced gold-protein interactions, which allows excess beads to be washed away or recycled. The well and bead sizes are chosen such that only one bead can be captured in each well. Filling efficiencies greater than 99.9% have been demonstrated across wafer-scale arrays with densities as high as 69 million beads per cm2. Potential applications for this technology include the assembly of DNA arrays for high-throughput genome sequencing and antibody arrays for proteomic studies. Following array assembly, this device may also be used to enhance the concentration-dependent processes of various assays through the accelerated transport of molecules using electric fields. PMID:19865735

Standardization of a cytometric p24-capture bead-assay for the detection of main HIV-1 subtypes.

PubMed

Merbah, Mélanie; Onkar, Sayali; Grivel, Jean-Charles; Vanpouille, Christophe; Biancotto, Angélique; Bonar, Lydia; Sanders-Buell, Eric; Kijak, Gustavo; Michael, Nelson; Robb, Merlin; Kim, Jerome H; Tovanabutra, Sodsai; Chenine, Agnès-Laurence

2016-04-01

The prevailing method to assess HIV-1 replication and infectivity is to measure the production of p24 Gag protein by enzyme-linked immunosorbent assay (ELISA). Since fluorescent bead-based technologies offer a broader dynamic range and higher sensitivity, this study describes a p24 capture Luminex assay capable of detecting HIV-1 subtypes A-D, circulating recombinant forms (CRF) CRF01_AE and CRF02_AG, which together are responsible for over 90% of HIV-1 infections worldwide. The success of the assay lies in the identification and selection of a cross-reactive capture antibody (clone 183-H12-5C). Fifty-six isolates that belonged to six HIV-1 subtypes and CRFs were successfully detected with p-values below 0.021; limits of detection ranging from 3.7 to 3 × 104 pg/ml. The intra- and inter-assay variation gave coefficient of variations below 6 and 14%, respectively. The 183-bead Luminex assay also displayed higher sensitivity of 91% and 98% compared to commercial p24 ELISA and a previously described Luminex assay. The p24 concentrations measured by the 183-bead Luminex assay showed a significant correlation (R=0.92, p<0.0001) with the data obtained from quantitative real time PCR. This newly developed p24 assay leverages the advantages of the Luminex platform, which include smaller sample volume and simultaneous detection of up to 500 analytes in a single sample, and delivers a valuable tool for the field. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface adsorption and hopping cause probe-size-dependent microrheology of actin networks

NASA Astrophysics Data System (ADS)

He, Jun; Tang, Jay X.

2011-04-01

A network of filaments formed primarily by the abundant cytoskeletal protein actin gives animal cells their shape and elasticity. The rheological properties of reconstituted actin networks have been studied by tracking micron-sized probe beads embedded within the networks. We investigate how microrheology depends on surface properties of probe particles by varying the stickiness of their surface. For this purpose, we chose carboxylate polystyrene (PS) beads, silica beads, bovine serum albumin (BSA) -coated PS beads, and polyethylene glycol (PEG) -grafted PS beads, which show descending stickiness to actin filaments, characterized by confocal imaging and microrheology. Probe size dependence of microrheology is observed for all four types of beads. For the slippery PEG beads, particle-tracking microrheology detects weaker networks using smaller beads, which tend to diffuse through the network by hopping from one confinement “cage” to another. This trend is reversed for the other three types of beads, for which microrheology measures stiffer networks for smaller beads due to physisorption of nearby filaments to the bead surface. We explain the probe size dependence with two simple models. We also evaluate depletion effect near nonadsorption bead surface using quantitative image analysis and discuss the possible impact of depletion on microrheology. Analysis of these effects is necessary in order to accurately define the actin network rheology both in vitro and in vivo.

Rapid structural analysis of nanomaterials in aqueous solutions

NASA Astrophysics Data System (ADS)

Ryuzaki, Sou; Tsutsui, Makusu; He, Yuhui; Yokota, Kazumichi; Arima, Akihide; Morikawa, Takanori; Taniguchi, Masateru; Kawai, Tomoji

2017-04-01

Rapid structural analysis of nanoscale matter in a liquid environment represents innovative technologies that reveal the identities and functions of biologically important molecules. However, there is currently no method with high spatio-temporal resolution that can scan individual particles in solutions to gain structural information. Here we report the development of a nanopore platform realizing quantitative structural analysis for suspended nanomaterials in solutions with a high z-axis and xy-plane spatial resolution of 35.8 ± 1.1 and 12 nm, respectively. We used a low thickness-to-diameter aspect ratio pore architecture for achieving cross sectional areas of analyte (i.e. tomograms). Combining this with multiphysics simulation methods to translate ionic current data into tomograms, we demonstrated rapid structural analysis of single polystyrene (Pst) beads and single dumbbell-like Pst beads in aqueous solutions.

Directed Differentiation of Embryonic Stem Cells Using a Bead-Based Combinatorial Screening Method

PubMed Central

Tarunina, Marina; Hernandez, Diana; Johnson, Christopher J.; Rybtsov, Stanislav; Ramathas, Vidya; Jeyakumar, Mylvaganam; Watson, Thomas; Hook, Lilian; Medvinsky, Alexander; Mason, Chris; Choo, Yen

2014-01-01

We have developed a rapid, bead-based combinatorial screening method to determine optimal combinations of variables that direct stem cell differentiation to produce known or novel cell types having pre-determined characteristics. Here we describe three experiments comprising stepwise exposure of mouse or human embryonic cells to 10,000 combinations of serum-free differentiation media, through which we discovered multiple novel, efficient and robust protocols to generate a number of specific hematopoietic and neural lineages. We further demonstrate that the technology can be used to optimize existing protocols in order to substitute costly growth factors with bioactive small molecules and/or increase cell yield, and to identify in vitro conditions for the production of rare developmental intermediates such as an embryonic lymphoid progenitor cell that has not previously been reported. PMID:25251366

Can Technology Help Promote Equality of Educational Opportunities?

ERIC Educational Resources Information Center

Jacob, Brian; Berger, Dan; Hart, Cassandra; Loeb, Susanna

2016-01-01

This chapter assesses the potential for several prominent technological innovations to promote equality of educational opportunities. We review the history of technological innovations in education and describe several prominent innovations, including intelligent tutoring, blended learning, and virtual schooling.

A novel magnet focusing plate for matrix-assisted laser desorption/ionization analysis of magnetic bead-bound analytes.

PubMed

Gode, David; Volmer, Dietrich A

2013-05-15

Magnetic beads are often used for serum profiling of peptide and protein biomarkers. In these assays, the bead-bound analytes are eluted from the beads prior to mass spectrometric analysis. This study describes a novel matrix-assisted laser desorption/ionization (MALDI) technique for direct application and focusing of magnetic beads to MALDI plates by means of dedicated micro-magnets as sample spots. Custom-made MALDI plates with magnetic focusing spots were made using small nickel-coated neodymium micro-magnets integrated into a stainless steel plate in a 16 × 24 (384) pattern. For demonstrating the proof-of-concept, commercial C-18 magnetic beads were used for the extraction of a test compound (reserpine) from aqueous solution. Experiments were conducted to study focusing abilities, the required laser energies, the influence of a matrix compound, dispensing techniques, solvent choice and the amount of magnetic beads. Dispensing the magnetic beads onto the micro-magnet sample spots resulted in immediate and strong binding to the magnetic surface. Light microscope images illustrated the homogeneous distribution of beads across the surfaces of the magnets, when the entire sample volume containing the beads was pipetted onto the surface. Subsequent MALDI analysis of the bead-bound analyte demonstrated excellent and reproducible ionization yields. The surface-assisted laser desorption/ionization (SALDI) properties of the strongly light-absorbing γ-Fe2O3-based beads resulted in similar ionization efficiencies to those obtained from experiments with an additional MALDI matrix compound. This feasibility study successfully demonstrated the magnetic focusing abilities for magnetic bead-bound analytes on a novel MALDI plate containing small micro-magnets as sample spots. One of the key advantages of this integrated approach is that no elution steps from magnetic beads were required during analyses compared with conventional bead experiments. Copyright © 2013 John Wiley & Sons, Ltd.

Molecular diagnostics using magnetic nanobeads

NASA Astrophysics Data System (ADS)

Zardán Gómez de la Torre, Teresa; Strömberg, Mattias; Göransson, Jenny; Gunnarsson, Klas; Nilsson, Mats; Svedlindh, Peter; Strømme, Maria

2010-01-01

In this paper, we investigate the volume-amplified magnetic nanobead detection assay with respect to bead size, bead concentration and bead oligonucleotide surface coverage in order to improve the understanding of the underlying microscopic mechanisms. It has been shown that: (i) the immobilization efficiency of the beads depends on the surface coverage of oligonucleotides, (ii) by using lower amounts of probe-tagged beads, detection sensitivity can be improved and (iii) using small enough beads enables both turn-off and turn-on detection. Finally, biplex detection was demonstrated.

A microhydrodynamic rationale for selection of bead size in preparation of drug nanosuspensions via wet stirred media milling.

PubMed

Li, Meng; Alvarez, Paulina; Bilgili, Ecevit

2017-05-30

Although wet stirred media milling has proven to be a robust process for producing nanoparticle suspensions of poorly water-soluble drugs and thereby enhancing their bioavailability, selection of bead size has been largely empirical, lacking fundamental rationale. This study aims to establish such rationale by investigating the impact of bead size at various stirrer speeds on the drug breakage kinetics via a microhydrodynamic model. To this end, stable suspensions of griseofulvin, a model BCS Class II drug, were prepared using hydroxypropyl cellulose and sodium dodecyl sulfate. The suspensions were milled at four different stirrer speeds (1000-4000rpm) using various sizes (50-1500μm) of zirconia beads. Laser diffraction, SEM, and XRPD were used for characterization. Our results suggest that there is an optimal bead size that achieves fastest breakage at each stirrer speed and that it shifts to a smaller size at higher speed. Calculated microhydrodynamic parameters reveal two counteracting effects of bead size: more bead-bead collisions with less energy/force upon a decrease in bead size. The optimal bead size exhibits a negative power-law correlation with either specific energy consumption or the microhydrodynamic parameters. Overall, this study rationalizes the use of smaller beads for more energetic wet media milling. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterisation of physico-mechanical properties and degradation potential of calcium alginate beads for use in embolisation.

PubMed

Forster, Richard E J; Thürmer, Frank; Wallrapp, Christine; Lloyd, Andrew W; Macfarlane, Wendy; Phillips, Gary J; Boutrand, Jean-Pierre; Lewis, Andrew L

2010-07-01

High molecular weight alginate beads with 59% mannuronic acid content or 68% guluronic acid were prepared using a droplet generator and crosslinked in calcium chloride. The alginate beads were compared to current embolisation microspheres for compressibility and monitored over 12 weeks for size and weight change at 37 degrees C in low volumes of ringers solutions. A sheep uterine model was used to analyse bead degradation and inflammatory response over 12 weeks. Both the in vitro and in vivo data show good delivery, with a compressibility similar to current embolic beads. In vitro, swelling was noted almost immediately and after 12 weeks the first signs of degradation were noted. No difference was noted in vivo. This study has shown that high molecular weight alginate gel beads were well tolerated by the body, but beads associated with induced thrombi were susceptible to inflammatory cell infiltration. The beads were shown to be easy to handle and were still observable after 3 months in vivo. The beads were robust enough to be delivered through a 2.7 Fr microcatheter. This study has demonstrated that high molecular weight, high purity alginate bead can be considered as semi-permanent embolisation beads, with the potential to bioresorb over time.

Highly sensitive bacteria quantification using immunomagnetic separation and electrochemical detection of guanine-labeled secondary beads.

PubMed

Jayamohan, Harikrishnan; Gale, Bruce K; Minson, Bj; Lambert, Christopher J; Gordon, Neil; Sant, Himanshu J

2015-05-22

In this paper, we report the ultra-sensitive indirect electrochemical detection of E. coli O157:H7 using antibody functionalized primary (magnetic) beads for capture and polyguanine (polyG) oligonucleotide functionalized secondary (polystyrene) beads as an electrochemical tag. Vacuum filtration in combination with E. coli O157:H7 specific antibody modified magnetic beads were used for extraction of E. coli O157:H7 from 100 mL samples. The magnetic bead conjugated E. coli O157:H7 cells were then attached to polyG functionalized secondary beads to form a sandwich complex (magnetic bead/E. coli secondary bead). While the use of magnetic beads for immuno-based capture is well characterized, the use of oligonucleotide functionalized secondary beads helps combine amplification and potential multiplexing into the system. The antibody functionalized secondary beads can be easily modified with a different antibody to detect other pathogens from the same sample and enable potential multiplexing. The polyGs on the secondary beads enable signal amplification up to 10⁸ guanine tags per secondary bead (7.5 x 10⁶ biotin-FITC per secondary bead, 20 guanines per oligonucleotide) bound to the target (E. coli). A single-stranded DNA probe functionalized reduced graphene oxide modified glassy carbon electrode was used to bind the polyGs on the secondary beads. Fluorescent imaging was performed to confirm the hybridization of the complex to the electrode surface. Differential pulse voltammetry (DPV) was used to quantify the amount of polyG involved in the hybridization event with tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)3(2+)) as the mediator. The amount of polyG signal can be correlated to the amount of E. coli O157:H7 in the sample. The method was able to detect concentrations of E. coli O157:H7 down to 3 CFU/100 mL, which is 67 times lower than the most sensitive technique reported in literature. The signal to noise ratio for this work was 3. We also demonstrate the use of the protocol for detection of E. coli O157:H7 seeded in waste water effluent samples.

Ensuring Equal Access to Technology: Providing Assistive Technology for Students with Disabilities

ERIC Educational Resources Information Center

Lee, Hwa; Templeton, Rosalyn

2008-01-01

With the passage of landmark federal laws, equal access to technology for all students, regardless of their abilities, has been getting increasing attention in the field of education. Although considering a continuum of assistive technology (AT) items and services for individuals with disabilities is a mandated practice, education and…

Design of the Illumina Porcine 50K+ SNP Iselect(TM) Beadchip and Characterization of the Porcine HapMap Population

USDA-ARS?s Scientific Manuscript database

Using next generation sequencing technology the International Swine SNP Consortium has identified 500,000 SNPs and used these to design an Illumina Infinium iSelect™ SNP BeadChip with a selection of 60,218 SNPs. The selected SNPs include previously validated SNPs and SNPs identified de novo using se...

New incompatibilities uncovered using the Promega DNA IQ™ chemistry.

PubMed

Laurin, Nancy; Célestin, Florence; Clark, Meagan; Wilkinson, Della; Yamashita, Brian; Frégeau, Chantal

2015-12-01

Over the years, the Promega DNA IQ™ System was proven an effective technology for the production of clean DNA from a wide variety of casework specimens. The capture of DNA using the DNA IQ™ paramagnetic beads, however, was shown to be affected by a few specific chemicals that could be present on exhibits submitted to the laboratory. In this study, various blood and latent fingerprint enhancement reagents/methods, marker pens and adhesive tapes, applied at the crime scene or in the forensic laboratory on casework exhibits or used to collect biological material, were tested for their compatibility with the DNA IQ™ technology. Although no impact on DNA recovery was observed for most reagents, the MAGNA™ Jet Black fingerprint powder and three 3M Scotch(®) adhesive tapes were shown to severely or completely inhibit DNA binding onto the DNA IQ™ beads. The effect of MAGNA™ Jet Black on DNA recovery could be counteracted by separating the magnetic powder from the lysates by centrifugation or filtration, prior to DNA extraction. High quality STR profiles were obtained from samples subjected to MAGNA™ Jet Black suggesting it does not impact DNA integrity. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

Floating dosage forms to prolong gastro-retention--the characterisation of calcium alginate beads.

PubMed

Stops, Frances; Fell, John T; Collett, John H; Martini, Luigi G

2008-02-28

Floating calcium alginate beads, designed to improve drug bioavailability from oral preparations compared with that from many commercially available and modified release products, have been investigated as a possible gastro-retentive dosage form. A model drug, riboflavin, was also incorporated into the formula. The aims of the current work were (a) to obtain information regarding the structure, floating ability and changes that occurred when the dosage form was placed in aqueous media, (b) to investigate riboflavin release from the calcium alginate beads in physiologically relevant media prior to in vivo investigations. Physical properties of the calcium alginate beads were investigated. Using SEM and ESEM, externally the calcium alginate beads were spherical in shape, and internally, air filled cavities were present thereby enabling floatation of the beads. The calcium alginate beads remained buoyant for times in excess of 13h, and the density of the calcium alginate beads was <1.000gcm(-3). Riboflavin release from the calcium alginate beads showed that riboflavin release was slow in acidic media, whilst in more alkali media, riboflavin release was more rapid. The characterisation studies showed that the calcium alginate beads could be considered as a potential gastro-retentive dosage form.

Controlled drug release properties of ionically cross-linked chitosan beads: the influence of anion structure.

PubMed

Shu, X Z; Zhu, K J

2002-02-21

By adopting a novel chitosan cross-linked method, i.e. chitosan/gelatin droplet coagulated at low temperature and then cross-linked by anions (sulfate, citrate and tripolyphosphate (TPP)), the chitosan beads were prepared. Scanning electron microscopy (SEM) observation showed that sulfate/chitosan and citrate/chitosan beads usually had a spherical shape, smooth surface morphology and integral inside structure. Cross-sectional analysis indicated that the cross-linking process of sulfate and citrate to chitosan was much faster than that of TPP due to their smaller molecular size. But, once completely cross-linked, TPP/chitosan beads possessed much better mechanical strength and the force to break the beads was approximately ten times higher than that of sulfate/chitosan or citrate/chitosan beads. Release media pH and ionic strength seriously influenced the controlled drug release properties of the beads, which related to the strength of electrostatic interaction between anions and chitosan. Sulfate and citrate cross-linked chitosan beads swelled and even dissociated in simulated gastric fluid (SGF) and hence, model drug (riboflavin) released completely in 5 h; while in simulated intestinal fluid (SIF), beads remained in a shrinkage state and drug released slowly (release % usually <70% in 24 h). However, swelling and drug release of TPP/chitosan bead was usually insensitive to media pH. Chitosan beads, cross-linked by a combination of TPP and citrate (or sulfate) together, not only had a good shape, but also improved pH-responsive drug release properties. Salt weakened the interaction of citrate, especially sulfate with chitosan and accelerated beads swelling and hence drug release rate, but it was insensitive to that of TPP/chitosan. These results indicate that ionically cross-linked chitosan beads may be useful in stomach specific drug delivery.

Elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate beads in vitro.

PubMed

Tulipan, Rachel J; Phillips, Heidi; Garrett, Laura D; Dirikolu, Levent; Mitchell, Mark A

2016-11-01

OBJECTIVE To characterize the elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CSH) beads in vitro. SAMPLE 60 carboplatin-impregnated CSH beads and 9 CSH beads without added carboplatin (controls). PROCEDURES Carboplatin-impregnated CSH beads (each containing 4.6 mg of carboplatin [2.4 mg of platinum]) were placed into separate 10-mL plastic tubes containing 5 mL of PBSS in groups of 1, 3, 6, or 10; 3 control beads were placed into a single tube of PBSS at the same volume. Experiments were conducted in triplicate at 37°C and a pH of 7.4 with constant agitation. Eluent samples were collected at 1, 2, 3, 6, 12, 24, and 72 hours. Samples were analyzed for platinum content by inductively coupled plasma-mass spectrometry. RESULTS The mean concentration of platinum released per carboplatin-impregnated bead over 72 hours was 445.3 mg/L. Cumulative concentrations of platinum eluted increased as the number of beads per tube increased. There was a significant difference in platinum concentrations over time, with values increasing over the first 12 hours and then declining for all tubes. There was also a significant difference in percentage of total incorporated platinum released into tubes with different numbers of beads: the percentage of eluted platinum was higher in tubes containing 1 or 3 beads than in those containing 6 or 10 beads. CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated CSH beads eluted platinum over 72 hours. Further studies are needed to determine whether implantation of carboplatin-impregnated CSH beads results in detectable levels of platinum systemically and whether the platinum concentrations eluted locally are toxic to tumor cells.

Analysis of platinum content in biodegradable carboplatin-impregnated beads and retrospective assessment of tolerability for intralesional use of the beads in dogs following excision of subcutaneous sarcomas: 29 cases (2011-2014).

PubMed

Hess, Theresa A; Drinkhouse, Macy E; Prey, Joshua D; Miller, Jonathan M; Fettig, Arthur A; Carberry, Carol A; Brenn, Stephen H; Bailey, Dennis B

2018-02-15

OBJECTIVE To evaluate platinum content in biodegradable carboplatin-impregnated beads and retrospectively assess tolerability and outcome data for dogs treated by intralesional placement of such beads following surgical excision of subcutaneous sarcomas. DESIGN Evaluation study and retrospective case series. SAMPLE 9 carboplatin-impregnated beads and 29 client-owned dogs. PROCEDURES Platinum content in 9 carboplatin-impregnated beads from 3 lots was measured by spectrophotometry, and calculated carboplatin content was compared with the labeled content. Medical records were searched to identify dogs with subcutaneous sarcomas for which treatment included placement of carboplatin-impregnated beads between 2011 and 2014. Signalment, tumor characteristics, surgical and histologic data, adverse events, and local recurrences were recorded. Associations between variables of interest and adverse events or local disease-free interval were analyzed. RESULTS In vitro analysis identified a mean ± SD platinum content of 5.38 ± 0.97 mg/bead. Calculated carboplatin content (10.24 ± 1.84 mg/bead) was significantly greater than the labeled amount (4.6 mg/bead). Bead weight and total platinum content differed significantly among lots, but platinum content per bead weight did not. Mild-to-moderate local adverse events were reported for 11 of 29 tumors; all resolved without additional surgery. No dogs had signs of systemic toxicosis. Overall local disease-free rates 1, 2, and 3 years after surgery were 70%, 70%, and 58%, respectively, as determined by Kaplan-Meier analysis. CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated beads were well tolerated; however, results of in vitro tests indicated that caution is needed because of manufacturing inconsistencies.

Gender Equality in Public Higher Education Institutions of Ethiopia: The Case of Science, Technology, Engineering, and Mathematics

ERIC Educational Resources Information Center

Egne, Robsan Margo

2014-01-01

Ensuring gender equality in higher education system is high on the agenda worldwide particularly in science disciplines. This study explores the problems and prospects of gender equality in public higher education institutions of Ethiopia, especially in science, technology, engineering, and mathematics. Descriptive survey and analytical research…

From the one-bead-one-compound concept to one-bead-one-reactor.

PubMed

Marani, Mariela M; Paradís-Bas, Marta; Tulla-Puche, Judit; Côté, Simón; Camperi, Silvia A; Cascone, Osvaldo; Albericio, Fernando

2007-01-01

The one-bead-one-compound method gives access to millions of compounds that can be screened directly on the bead. Although characterization techniques are increasingly potent and reliable, problems can still be encountered in deciphering the sequence of the active compound because of sensitiveness or manipulation of the bead. ChemMatrix, a totally PEG-based resin, has resolved the synthesis of peptides of outstanding difficulty. Like other PEG-based resins, it permits on-bead screening because of its compatibility in aqueous media and has the further advantage of having a high loading, comparable to polystyrene resins. ChemMatrix beads previously swelled in water can be nicely divided into four parts that can be characterized using different analytical techniques or just stored for safety or for further testing. The four bead parts show high homogeneity and can thus be considered to be replicas.

Synthesis and characterization of nanoporous silica aerogel beads using cheap industrial grade sodium silacte precursor

NASA Astrophysics Data System (ADS)

Khan, Tasneem M. A.; Khan, Asiya; Sarawade, Pradip B.

2018-05-01

We report a method to synthesize low-density transparent mesoporous silica aerogel beads by ambient pressure drying (APD). The beads were prepared by acid-base sol-gel polymerization of sodium silicate in via the ball dropping method (BDM). To minimize shrinkage during drying, wet silica beads were initially prepared; their surfaces were then modified using trimethylchlorosilane (TMCS) via simultaneous solvent exchange and surface modification. The specific surface area and cumulative pore volume of the silica aerogel beads increased with an increase in the %V of TMCS. Silica aerogel beads with low packing bed density, high surface area, and large cumulative pore volume was obtained when TMCS was used. Properties of the final product were examined by BET, and TG-DT analyses. The hydrophobic silica aerogel beads were thermally stable up to 350°C. We discuss our results and compare our findings for modified versus unmodified silica beads.

Silk sericin-alginate-chitosan microcapsules: hepatocytes encapsulation for enhanced cellular functions.

PubMed

Nayak, Sunita; Dey, Sanchareeka; Kundu, Subhas C

2014-04-01

The encapsulation based technology permits long-term delivery of desired therapeutic products in local regions of body without the need of immunosuppressant drugs. In this study microcapsules composed of sericin and alginate micro bead as inner core and with an outer chitosan shell are prepared. This work is proposed for live cell encapsulation for potential therapeutic applications. The sericin protein is obtained from cocoons of non-mulberry silkworm Antheraea mylitta. The sericin-alginate micro beads are prepared via ionotropic gelation under high applied voltage. The beads further coated with chitosan and crosslinked with genipin. The microcapsules developed are nearly spherical in shape with smooth surface morphology. Alamar blue assay and confocal microscopy indicate high cell viability and uniform encapsulated cell distribution within the sericin-alginate-chitosan microcapsules indicating that the microcapsules maintain favourable microenvironment for the cells. The functional analysis of encapsulated cells demonstrates that the glucose consumption, urea secretion rate and intracellular albumin content increased in the microcapsules. The study suggests that the developed sericin-alginate-chitosan microcapsule contributes towards the development of cell encapsulation model. It also offers to generate enriched population of metabolically and functionally active cells for the future therapeutics especially for hepatocytes transplantation in acute liver failure. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel, bio-based, photoactive arsenic sorbent: TiO₂-impregnated chitosan bead.

PubMed

Miller, Sarah M; Zimmerman, Julie B

2010-11-01

A novel sorbent for arsenic, TiO(2)-impregnated chitosan bead (TICB), has been synthesized and successfully tested. Kinetic plots, pH dependence, isotherm data, and bead morphology are reported. Equilibrium is achieved after 185 h in batch experiments with exposure to UV light. The TICB system performs similarly to the mass equivalent of neat TiO(2) nanopowder. The point of zero charge (pzc) for TICB was determined to be 7.25, and as with other TiO(2)-based arsenic removal technologies, the optimal pH range for sorption is below this pH(pzc). Without exposure to UV light, TICB removes 2198 μg As(III)/g TICB and 2050 μg As(V)/g TICB. With exposure to UV light, TICB achieves photo-oxidation of As(III) to As(V), the less toxic and more easily sequestered arsenic form. UV irradiation also results in enhanced arsenic removal, reaching sorption capacities of 6400 μg As/g TICB and 4925 μg As/g TICB, where arsenic is initially added as As(III) and As(V), respectively. Because the TICB system obviates filtration post-treatment, TICB is superior to TiO(2) nanopowder from the perspective of implementation for decentralized water treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

A high-throughput liquid bead array-based screening technology for Bt presence in GMO manipulation.

PubMed

Fu, Wei; Wang, Huiyu; Wang, Chenguang; Mei, Lin; Lin, Xiangmei; Han, Xueqing; Zhu, Shuifang

2016-03-15

The number of species and planting areas of genetically modified organisms (GMOs) has been rapidly developed during the past ten years. For the purpose of GMO inspection, quarantine and manipulation, we have now devised a high-throughput Bt-based GMOs screening method based on the liquid bead array. This novel method is based on the direct competitive recognition between biotinylated antibodies and beads-coupled antigens, searching for Bt presence in samples if it contains Bt Cry1 Aa, Bt Cry1 Ab, Bt Cry1 Ac, Bt Cry1 Ah, Bt Cry1 B, Bt Cry1 C, Bt Cry1 F, Bt Cry2 A, Bt Cry3 or Bt Cry9 C. Our method has a wide GMO species coverage so that more than 90% of the whole commercialized GMO species can be identified throughout the world. Under our optimization, specificity, sensitivity, repeatability and availability validation, the method shows a high specificity and 10-50 ng/mL sensitivity of quantification. We then assessed more than 1800 samples in the field and food market to prove capacity of our method in performing a high throughput screening work for GMO manipulation. Our method offers an applicant platform for further inspection and research on GMO plants. Copyright © 2015 Elsevier B.V. All rights reserved.

Multistage open-tube trap for enrichment of part-per-trillion trace components of low-pressure (below 27-kPa) air samples

NASA Technical Reports Server (NTRS)

Ohara, D.; Vo, T.; Vedder, J. F.

1985-01-01

A multistage open-tube trap for cryogenic collection of trace components in low-pressure air samples is described. The open-tube design allows higher volumetric flow rates than densely packed glass-bead traps commonly reported and is suitable for air samples at pressures below 27 kPa with liquid nitrogen as the cryogen. Gas blends containing 200 to 2500 parts per trillion by volume each of ethane and ethene were sampled and hydrocarbons were enriched with 100 + or - 4 percent trap efficiency. The multistage design is more efficient than equal-length open-tube traps under the conditions of the measurements.

Method for preparing spherical ferrite beads and use thereof

DOEpatents

Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.

2002-01-01

The invention allows the fabrication of small, dense, highly polished spherical beads of hexagonal ferrites with selected compositions for use in nonreciprocal microwave and mm-wave devices as well as in microwave absorbent or reflective coatings, composites, and the like. A porous, generally spherical bead of hydrous iron oxide is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead is washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) under conditions of elevated temperature and pressure to convert the bead into a mixed hydrous iron-alkaline earth oxide while retaining the generally spherical shape. This mixed oxide bead is then washed, dried, and calcined to produce the desired (BaFe.sub.12 O.sub.19 or SrFe.sub.12 O.sub.19) crystal structure. The calcined bead is then sintered to form a dense bead of the BaFe.sub.12 O.sub.19 and SrFe.sub.12 O.sub.19 phase suitable for polishing and incorporation into various microwave devices and components.

Congo red adsorption from aqueous solutions by using chitosan hydrogel beads impregnated with nonionic or anionic surfactant.

PubMed

Chatterjee, Sudipta; Lee, Dae S; Lee, Min W; Woo, Seung H

2009-09-01

The adsorption performance of CS beads impregnated with triton X-100 (TX-100) as a nonionic surfactant and sodium dodecyl sulfate (SDS) as an anionic surfactant was investigated for the removal of anionic dye (congo red) from aqueous solution. While the adsorption capacity of CS/TX-100 beads was enhanced at all concentrations of TX-100 (0.005-0.1%), the increase in the concentration of SDS above 0.01% in the CS/SDS beads gradually reduced the adsorption capacity of the beads. Equilibrium adsorption isotherm data indicated a good fit to the Sips isotherm model and a heterogeneous adsorption process. The Sips maximum adsorption capacity in dry weight of the CS/TX-100 beads was 378.79 mg/g and 318.47 mg/g for the CS/SDS beads, higher than the 223.25mg/g of the CS beads. Modification of CS beads by impregnation with nonionic surfactant, or even anionic surfactant, at low concentrations is a possible way to enhance adsorption of anionic dye.

Optical Manipulation of Single Magnetic Beads in a Microwell Array on a Digital Microfluidic Chip.

PubMed

Decrop, Deborah; Brans, Toon; Gijsenbergh, Pieter; Lu, Jiadi; Spasic, Dragana; Kokalj, Tadej; Beunis, Filip; Goos, Peter; Puers, Robert; Lammertyn, Jeroen

2016-09-06

The detection of single molecules in magnetic microbead microwell array formats revolutionized the development of digital bioassays. However, retrieval of individual magnetic beads from these arrays has not been realized until now despite having great potential for studying captured targets at the individual level. In this paper, optical tweezers were implemented on a digital microfluidic platform for accurate manipulation of single magnetic beads seeded in a microwell array. Successful optical trapping of magnetic beads was found to be dependent on Brownian motion of the beads, suggesting a 99% chance of trapping a vibrating bead. A tailor-made experimental design was used to screen the effect of bead type, ionic buffer strength, surfactant type, and concentration on the Brownian activity of beads in microwells. With the optimal conditions, the manipulation of magnetic beads was demonstrated by their trapping, retrieving, transporting, and repositioning to a desired microwell on the array. The presented platform combines the strengths of digital microfluidics, digital bioassays, and optical tweezers, resulting in a powerful dynamic microwell array system for single molecule and single cell studies.

Technology Prompts New Understandings: The Case of Equality

ERIC Educational Resources Information Center

Bardini, Caroline; Oldenburg, Reinhard; Stacey, Kaye; Pierce, Robyn

2013-01-01

Changes to students' understanding of mathematical notation may be brought about by using technology within mathematics. Taking equality as a case study, the paper provides brief epistemological, historical, didactical, and computational reviews of its symbolic representation in pen-and-paper and technology-assisted mathematics, most especially in…

77 FR 32986 - Notice of Inventory Completion: The University of Alabama Museums, Tuscaloosa, AL

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-04

... than 2,032 glass beads, 1 lot of more than 17 shell beads, 1 unidentified bead, 1 gun lock, 1 gun butt plate, 1 gun stock, 2 gun barrels, 1 brass ramrod support, 8 musket balls, 2 iron buckles, 1 iron handle... fragments, 1 unidentified bead, 2 glass beads, 1 gun flint, 1 iron knife blade, 1 iron nail, 1 musket ball...

Magnetic bead detection using nano-transformers.

PubMed

Kim, Hyung Kwon; Hwang, Jong Seung; Hwang, Sung Woo; Ahn, Doyeol

2010-11-19

A novel scheme to detect magnetic beads using a nano-scale transformer with a femtoweber resolution is reported. We have performed a Faraday's induction experiment with the nano-transformer at room temperature. The transformer shows the linear output voltage responses to the sinusoidal input current. When magnetic beads are placed on the transformer, the output responses are increased by an amount corresponding to the added magnetic flux from the beads when compared with the case of no beads on the transformer. In this way, we could determine whether magnetic beads are on top of the transformer in a single particle level.

Phosphate uptake studies of cross-linked chitosan bead materials.

PubMed

Mahaninia, Mohammad H; Wilson, Lee D

2017-01-01

A systematic experimental study is reported that provides a molecular based understanding of cross-linked chitosan beads and their adsorption properties in aqueous solution containing phosphate dianion (HPO 4 2- ) species. Synthetically modified chitosan using epichlorohydrin and glutaraldehyde cross-linkers result in surface modified beads with variable hydrophile-lipophile character and tunable HPO 4 2- uptake properties. The kinetic and thermodynamic adsorption properties of cross-linked chitosan beads with HPO 4 2- species were studied in aqueous solution. Complementary structure and physicochemical characterization of chitosan beads via potentiometry, Raman spectroscopy, DSC, and dye adsorption measurements was carried out to establish structure-property relationships. The maximum uptake (Q m ) of bead systems with HPO 4 2- at equilibrium was 52.1mgg -1 ; whereas, kinetic uptake results for chitosan bead/phosphate systems are relatively rapid (0.111-0.113min -1 ) with an intraparticle diffusion rate-limiting step. The adsorption process follows a multi-step pathway involving inner- and outer-sphere complexes with significant changes in hydration. Phosphate uptake strongly depends on the composition and type of cross-linker used for preparation of chitosan beads. The adsorption isotherms and structural characterization of bead systems illustrate the role of surface charge, hydrophile-lipophile balance, adsorption site accessibility, and hydration properties of the chitosan bead surface. Copyright © 2016 Elsevier Inc. All rights reserved.

Determining the unique refractive index properties of solid polystyrene aerosol using broadband Mie scattering from optically trapped beads.

PubMed

Jones, Stephanie H; King, Martin D; Ward, Andrew D

2013-12-21

A method is described to measure the refractive index dispersion with wavelength of optically trapped solid particles in air. Knowledge of the refraction properties of solid particles is critical for the study of aerosol; both in the laboratory and in the atmosphere for climate studies. Single micron-sized polystyrene beads were optically trapped in air using a vertically aligned counter-propagating configuration of focussed laser beams. Each bead was illuminated using white light from a broadband light emitting diode (LED) and elastic scattering within the bead was collected onto a spectrograph. The resulting Mie spectra were analysed to accurately determine polystyrene bead radii to ±0.4 nm and values of the refractive index to ±0.0005 over a wavelength range of 480-700 nm. We demonstrate that optical trapping combined with elastic scattering can be used to both accurately size polystyrene beads suspended in air and determine their wavelength dependent refractive index. The refractive index dispersions are in close agreement with reported values for polystyrene beads in aqueous dispersion. Our results also demonstrate a variation in the refractive index of polystyrene, from bead to bead, in a commercial sample. The measured variation highlights that care must be taken when using polystyrene beads as a calibration aerosol.

Carryover effects associated with the single-trial passive avoidance learning task in the young chick.

PubMed

Crowe, Simon F; Hale, Matthew W

2002-09-01

The single-trial passive avoidance task is a useful procedure for examining learning and memory in the young chick. However, it has recently been suggested that discrepant results reported by different laboratories are due to differences in training procedure. The present study investigated a number of parameters surrounding the passive avoidance task, using day-old White Leghorn, Black Australorp cockerels. The results suggested that presentation of a water-dipped bead immediately after the aversive bead significantly altered retention levels. In addition, when the water-dipped bead was presented after the aversive bead, chicks failed to discriminate between beads for a period of 10 min following exposure to the aversant experience. A novel variant of the passive avoidance procedure, involving pretraining with a water-dipped red bead, training with an aversant-coated red bead, and testing with a dry red bead, was evaluated. A measure of avoidance was calculated using all three trials. It is suggested that the use of a single bead, measured both before and after the training experience and using both aversant- and water-trained controls, results in the most concise characterization of memory-related phenomena in the chick which is not contaminated by a carryover effect from the aversive training experience to the nonaversive bead.

Echicetin Coated Polystyrene Beads: A Novel Tool to Investigate GPIb-Specific Platelet Activation and Aggregation

PubMed Central

Petunin, Alexey; Clemetson, Kenneth J.; Gambaryan, Stepan; Walter, Ulrich

2014-01-01

von Willebrand factor/ristocetin (vWF/R) induces GPIb-dependent platelet agglutination and activation of αIIbβ3 integrin, which also binds vWF. These conditions make it difficult to investigate GPIb-specific signaling pathways in washed platelets. Here, we investigated the specific mechanisms of GPIb signaling using echicetin-coated polystyrene beads, which specifically activate GPIb. We compared platelet activation induced by echicetin beads to vWF/R. Human platelets were stimulated with polystyrene beads coated with increasing amounts of echicetin and platelet activation by echicetin beads was then investigated to reveal GPIb specific signaling. Echicetin beads induced αIIbβ3-dependent aggregation of washed platelets, while under the same conditions vWF/R treatment led only to αIIbβ3-independent platelet agglutination. The average distance between the echicetin molecules on the polystyrene beads must be less than 7 nm for full platelet activation, while the total amount of echicetin used for activation is not critical. Echicetin beads induced strong phosphorylation of several proteins including p38, ERK and PKB. Synergistic signaling via P2Y12 and thromboxane receptor through secreted ADP and TxA2, respectively, were important for echicetin bead triggered platelet activation. Activation of PKG by the NO/sGC/cGMP pathway inhibited echicetin bead-induced platelet aggregation. Echicetin-coated beads are powerful and reliable tools to study signaling in human platelets activated solely via GPIb and GPIb-triggered pathways. PMID:24705415

Basket design as a factor in retention and release of calculi in vitro.

PubMed

Zeltser, Ilia S; Bagley, Demetrius H

2007-03-01

To compare stone retrieval and release from seven basket designs in vitro. We tested two tipped and one tipless NCompass models, three other tipless Nitinol designs (NCircle, Sur-Catch, and Dimension), and the Segura Hemisphere for their ability to retrieve and release single beads 8, 6, 5.6, and 5 mm diameter and multiple beads 3.6 mm diameter in both a ureteral and a caliceal model in three separate attempts. In the ureteral model, all baskets were successful in retrieving all sizes of single beads. With multiple 3.6-mm beads, only the NCompass and Dimension designs were able to retrieve at least two of three beads in all attempts. With the exception of the Segura Hemisphere, all designs were successful in releasing all bead sizes. In the caliceal model, only the NCircle, Dimension, and tipless NCompass models were able to retrieve all bead sizes in 100% of the trials. The tipped NCompass and Hemisphere designs were unable to retrieve any beads in this model. The Sur-Catch basket was successful in the retrieval of large beads only. The Dimension articulating design was the only basket able to release all bead sizes in all attempts. The tipless NCompass basket did not release any of the beads once engaged. Nitinol basket designs show excellent retrieval and release capabilities in the in-vitro ureteral model. The articulating Nitinol basket has the best stone-releasing capability of all baskets tested.

Rhenium-coated glass beads for intracolonic administration attenuate TNBS-induced colitis in mice: Proof-of-Concept Study.

PubMed

Siczek, Krzysztof; Zatorski, Hubert; Pawlak, Wojciech; Fichna, Jakub

2015-01-01

In search for novel effective treatments in inflammatory bowel diseases, a new strategy employing glass beads coated with rhenium nanolayer has been developed and validated in the mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Briefly, mice were randomly divided into 5 experimental groups: control (vehicle alone, Group 1); control treated with rhenium-coated glass beads (Group 2); TNBS (Group 3); TNBS treated with rhenium-coated glass beads (Group 4); and TNBS treated with uncoated glass beads (Group 5). Mice from Group 2, 4 and 5 were treated with respective beads (once daily, 5 beads / animal, i.c.) between D3-D6 post-TNBS/vehicle and evaluation of colonic damage was performed on D7, based on macroscopic scoring and clinical parameters. Severe colonic inflammation developed in post-TNBS mice (Group 3) [P <0.001 vs. control (Group 1) for macroscopic score], which was significantly attenuated by treatment with rhenium-coated glass beads (Group 4) [P <0.01 vs. TNBS (Group 3), for macroscopic score]. Neither rhenium-coated glass beads had any effect in control animals (Group 2), nor uncoated glass beads influenced TNBS-induced colitis (Group 5). In conclusion, a novel and attractive strategy for the treatment of colonic inflammation has been proposed; therapy with rhenium-coated glass beads already proved effective in the mouse model of TNBS-induced colitis, now requires further characterization in clinical conditions.

Structurally stable gel bead containing entrapped enzyme and method for manufacture thereof

DOEpatents

Woodward, J.

1998-12-08

This research provides a structurally stable gel bead containing an entrapped enzyme and a method for its manufacture. The enzyme is covalently cross-linked to gelatin in the presence of glutaraldehyde prior to the formation of the gel bead, to prevent leakage of the enzyme. Propylene glycol alginate is then added to the mixture. Once the gel beads are formed, they are then soaked in glutaraldehyde, which imparts structural stability to the gel beads. This method can be used with many types of enzymes, such as proteases, carbohydrases, proteases, ligases, isomerases, oxidoreductases, and specialty enzymes. These and other enzymes can be immobilized in the gel beads and utilized in a number of enzymatic processes. Exogenously added ions are not required to maintain the structural stability of these gel beads. 7 figs.

Structurally stable gel bead containing entrapped enzyme and method for manufacture thereof

DOEpatents

Woodward, Jonathan

1998-01-01

A structurally stable gel bead containing an entrapped enzyme and a method for its manufacture. The enzyme is covalently cross-linked to gelatin in the presence of glutaraldehyde prior to the formation of the gel bead, to prevent leakage of the enzyme. Propylene glycol alginate is then added to the mixture. Once the gel beads are formed, they are then soaked in glutaraldehyde, which imparts structural stability to the gel beads. This method can be used with many types of enzymes, such as proteases, carbohydrases, proteases, ligases, isomerases, oxidoreductases, and specialty enzymes. These and other enzymes can be immobilized in the gel beads and utilized in a number of enzymatic processes. Exogenously added ions are not required to maintain the structural stability of these gel beads.

Studying the protein organization of the postsynaptic density by a novel solid phase- and chemical cross-linking-based technology.

PubMed

Liu, Szu-Heng; Cheng, Huei-Hsuan; Huang, San-Yuan; Yiu, Pei-Chun; Chang, Yen-Chung

2006-06-01

Agarose beads carrying a cleavable, fluorescent, and photoreactive cross-linking reagent on the surface were synthesized and used to selectively pull out the proteins lining the surface of supramolecules. A quantitative comparison of the abundances of various proteins in the sample pulled out by the beads from supramolecules with their original abundances could provide information on the spatial arrangement of these proteins in the supramolecule. The usefulness of these synthetic beads was successfully verified by trials using a synthetic protein complex consisting of three layers of different proteins on glass coverslips. By using these beads, we determined the interior or superficial locations of five major and 19 minor constituent proteins in the postsynaptic density (PSD), a large protein complex and the landmark structure of asymmetric synapses in the mammalian central nervous system. The results indicate that alpha,beta-tubulins, dynein heavy chain, microtubule-associated protein 2, spectrin, neurofilament H and M subunits, an hsp70 protein, alpha-internexin, dynamin, and PSD-95 protein reside in the interior of the PSD. Dynein intermediate chain, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors, kainate receptors, N-cadherin, beta-catenin, N-ethylmaleimide-sensitive factor, an hsc70 protein, and actin reside on the surface of the PSD. The results further suggest that the N-methyl-d-aspartate receptors and the alpha-subunits of calcium/calmodulin-dependent protein kinase II are likely to reside on the surface of the PSD although with unique local protein organizations. Based on our results and the known interactions between various PSD proteins from data mining, a model for the molecular organization of the PSD is proposed.

Development of electrospun beaded fibers from Thai silk fibroin and gelatin for controlled release application.

PubMed

Somvipart, Siraporn; Kanokpanont, Sorada; Rangkupan, Rattapol; Ratanavaraporn, Juthamas; Damrongsakkul, Siriporn

2013-04-01

Thai silk fibroin and gelatin are attractive biomaterials for tissue engineering and controlled release applications due to their biocompatibility, biodegradability, and bioactive properties. The development of electrospun fiber mats from silk fibroin and gelatin were reported previously. However, burst drug release from such fiber mats remained the problem. In this study, the formation of beads on the fibers aiming to be used for the sustained release of drug was of our interest. The beaded fiber mats were fabricated using electrospinning technique by controlling the solution concentration, weight blending ratio of Thai silk fibroin/gelatin blend, and applied voltage. It was found that the optimal conditions including the solution concentration and the weight blending ratio of Thai silk fibroin/gelatin at 8-10% (w/v) and 70/30, respectively, with the applied voltage at 18 kV provided the fibers with homogeneous formation of beads. Then, the beaded fiber mats obtained were crosslinked by the reaction of carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS). Methylene blue as a model active compound was loaded on the fiber mats. The release test of methylene blue from the beaded fiber mats was carried out in comparison to that of the smooth fiber mats without beads. It was found that the beaded fiber mats could prolong the release of methylene blue, comparing to the smooth fiber mats without beads. This was possibly due to the beaded fiber mats that would absorb and retain higher amount of methylene blue than the fiber mats without beads. Thai silk fibroin/gelatin beaded fiber mats were established as an effective carrier for the controlled release applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Formulation and characterization of a compacted multiparticulate system for modified release of water-soluble drugs--Part II theophylline and cimetidine.

PubMed

Cantor, Stuart L; Hoag, Stephen W; Augsburger, Larry L

2009-05-01

The purpose was to investigate the effectiveness of an ethylcellulose (EC) bead matrix and different film-coating polymers in delaying drug release from compacted multiparticulate systems. Formulations containing theophylline or cimetidine granulated with Eudragit RS 30D were developed and beads were produced by extrusion-spheronization. Drug beads were coated using 15% wt/wt Surelease or Eudragit NE 30D and were evaluated for true density, particle size, and sphericity. Lipid-based placebo beads and drug beads were blended together and compacted on an instrumented Stokes B2 rotary tablet press. Although placebo beads were significantly less spherical, their true density of 1.21 g/cm(3) and size of 855 mum were quite close to Surelease-coated drug beads. Curing improved the crushing strength and friability values for theophylline tablets containing Surelease-coated beads; 5.7 +/- 1.0 kP and 0.26 +/- 0.07%, respectively. Dissolution profiles showed that the EC matrix only provided 3 h of drug release. Although tablets containing Surelease-coated theophylline beads released drug fastest overall (t(44.2%) = 8 h), profiles showed that coating damage was still minimal. Size and density differences indicated a minimal segregation potential during tableting for blends containing Surelease-coated drug beads. Although modified release profiles >8 h were achievable in tablets for both drugs using either coating polymer, Surelease-coated theophylline beads released drug fastest overall. This is likely because of the increased solubility of theophylline and the intrinsic properties of the Surelease films. Furthermore, the lipid-based placebos served as effective cushioning agents by protecting coating integrity of drug beads under a number of different conditions while tableting.

Guar gum succinate-sodium alginate beads as a pH-sensitive carrier for colon-specific drug delivery.

PubMed

Seeli, D Sathya; Dhivya, S; Selvamurugan, N; Prabaharan, M

2016-10-01

Guar gum succinate - sodium alginate (GGS-SA) beads cross-linked with barium ions were prepared and characterized as a pH sensitive carrier for colon-specific drug delivery. The structure of GGS-SA beads was confirmed by FT-IR spectroscopy. Scanning Electron Microscope (SEM) studies revealed that the drug loaded GGS-SA beads prepared using 2:2 (w/v) weight percent of GGS and SA had a diameter about 1.4mm and roughly spherical in shape. X-ray diffraction (XRD) studies showed that the peaks corresponding to GGS and SA at 13.5°, 17.5°, 20.2° and 13.5°, 22°, 24.1°, respectively were destroyed in GGS-SA beads which show that these beads are more amorphous in nature. Swelling studies demonstrated the pH-dependent swelling behavior of GGS-SA beads. The beads showed higher swelling degrees in pH 7.4 than that in pH 1.2 due to the existence of anionic groups in the polymer chains. The drug release study showed that the amount of model drug, ibuprofen, released from the GGS-SA beads was higher in pH 7.4 than that in pH 1.2 due to the pH-dependent swelling behavior of the beads. MTT assay revealed that GGS-SA beads at a concentration range of 0-30μg/ml had no cytotoxic effect on the cultured mouse mesenchymal stem cells (C3H10T1/2). These results suggest that GGS-SA beads can be used as effective colon-specific drug delivery system with pH-dependent drug release ability. Copyright © 2016 Elsevier B.V. All rights reserved.

Steady-state force-velocity relation in the ATP-dependent sliding movement of myosin-coated beads on actin cables in vitro studied with a centrifuge microscope.

PubMed Central

Oiwa, K; Chaen, S; Kamitsubo, E; Shimmen, T; Sugi, H

1990-01-01

To eliminate the gap between the biochemistry of actomyosin in solution and the physiology of contracting muscle, we developed an in vitro force-movement assay system in which the steady-state force-velocity relation in the actin-myosin interaction can be studied. The assay system consists of the internodal cells of an alga, Nitellopsis obtusa, containing well-organized actin filament arrays (actin cables); tosyl-activated polystyrene beads (diameter, 2.8 microns; specific gravity, 1.3) coated with skeletal muscle myosin; and a centrifuge microscope equipped with a stroboscopic light source and a video system. The internodal cell preparation was mounted on the rotor of the centrifuge microscope, so that centrifugal forces were applied to the myosin-coated beads moving along the actin cables in the presence of ATP. Under constant centrifugal forces directed opposite to the bead movement ("positive" loads), the beads continued to move with constant velocities, which decreased with increasing centrifugal forces. The steady-state force-velocity curve thus obtained was analogous to the double-hyperbolic force-velocity curve of single muscle fibers. The unloaded velocity of bead movement was 1.6-3.6 microns/s (20-23 degrees C), while the maximum "isometric" force generated by the myosin molecules on the bead was 1.9-39 pN. If, on the other hand, the beads were subjected to constant centrifugal forces in the direction of bead movement ("negative" loads), the bead also moved with constant velocities. Unexpectedly, the velocity of bead movement did not increase with increasing negative loads but first decreased by 20-60% and then increased towards the initial unloaded velocity until the beads were eventually detached from the actin cables. Images PMID:2236007

Steady-state force-velocity relation in the ATP-dependent sliding movement of myosin-coated beads on actin cables in vitro studied with a centrifuge microscope.

PubMed

Oiwa, K; Chaen, S; Kamitsubo, E; Shimmen, T; Sugi, H

1990-10-01

To eliminate the gap between the biochemistry of actomyosin in solution and the physiology of contracting muscle, we developed an in vitro force-movement assay system in which the steady-state force-velocity relation in the actin-myosin interaction can be studied. The assay system consists of the internodal cells of an alga, Nitellopsis obtusa, containing well-organized actin filament arrays (actin cables); tosyl-activated polystyrene beads (diameter, 2.8 microns; specific gravity, 1.3) coated with skeletal muscle myosin; and a centrifuge microscope equipped with a stroboscopic light source and a video system. The internodal cell preparation was mounted on the rotor of the centrifuge microscope, so that centrifugal forces were applied to the myosin-coated beads moving along the actin cables in the presence of ATP. Under constant centrifugal forces directed opposite to the bead movement ("positive" loads), the beads continued to move with constant velocities, which decreased with increasing centrifugal forces. The steady-state force-velocity curve thus obtained was analogous to the double-hyperbolic force-velocity curve of single muscle fibers. The unloaded velocity of bead movement was 1.6-3.6 microns/s (20-23 degrees C), while the maximum "isometric" force generated by the myosin molecules on the bead was 1.9-39 pN. If, on the other hand, the beads were subjected to constant centrifugal forces in the direction of bead movement ("negative" loads), the bead also moved with constant velocities. Unexpectedly, the velocity of bead movement did not increase with increasing negative loads but first decreased by 20-60% and then increased towards the initial unloaded velocity until the beads were eventually detached from the actin cables.

Force measurements of a magnetic micro actuator proposed for a microvalve array

NASA Astrophysics Data System (ADS)

Chang, Pauline J.; Chang, Frank W.; Yuen, Michelle C.; Otillar, Robert; Horsley, David A.

2014-03-01

Low-cost, easily-fabricated and power-efficient microvalves are necessary for many microfluidic lab-on-a-chip applications. In this study, we present a simple, low-power, scalable, CMOS-compatible magnetic actuator for microvalve applications composed of a paramagnetic bead as the ball valve over a picoliter reaction well etched into a silicon substrate. The paramagnetic bead, composed of either pure FeSi or magnetite in a SiO2 matrix, is actuated by the local magnetic field gradient generated by a microcoil in an aqueous environment, and the reaction well is situated at the microcoil center. A permanent magnet beneath the microvalve device provides an external magnetic biasing field that magnetizes the bead, enabling bidirectional actuation and reducing the current required to actuate the bead to a level below 10 mA. The vertical and radial magnetic forces exerted on the bead by the microcoil were measured for both pure FeSi and composite beads and agree well with the predictions of 2D axisymmetric finite element method models. Vertical forces were within a range of 13-80 nN, and radial forces were 11-60 nN depending on the bead type. The threshold current required to initiate bead actuation was measured as a function of bead diameter and is found to scale inversely with volume for small beads, as expected based on the magnetic force model. To provide an estimate of the stiction force acting between the bead and the passivation layer on the substrate, repeated actuation trials were used to study the bead throw distance for substrates coated with silicon dioxide, Parylene-C, and photoresist. The stiction observed was lowest for a photoresist-coated substrate, while silicon dioxide and Parylene-C coated substrates exhibited similar levels of stiction.

Head-on collision between two solitary waves in a one-dimensional bead chain

NASA Astrophysics Data System (ADS)

Wang, Fu-Gang; Yang, Yang-Yang; Han, Juan-Fang; Duan, Wen-Shan

2018-04-01

Not Available Project supported by the National Magnetic Confinement Fusion Science Program of China (Grant No. 2014GB104002), the National Natural Science Foundation of China (Grant No. 11647313), the Youth Science and Technology Foundation of Gansu Province, China (Grant No. 1606RJYA263), and the Institutes of Higher Education Institutions of Gansu Province, China (Grant No. 2015B-022).

Microscale assembly directed by liquid-based template.

PubMed

Chen, Pu; Luo, Zhengyuan; Güven, Sinan; Tasoglu, Savas; Ganesan, Adarsh Venkataraman; Weng, Andrew; Demirci, Utkan

2014-09-10

A liquid surface established by standing waves is used as a dynamically reconfigurable template to assemble microscale materials into ordered, symmetric structures in a scalable and parallel manner. The broad applicability of this technology is illustrated by assembling diverse materials from soft matter, rigid bodies, individual cells, cell spheroids and cell-seeded microcarrier beads. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for preparing dielectric composite materials

DOEpatents

Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.; Felten, John J.

2004-11-23

The invention allows the fabrication of small, dense beads of dielectric materials with selected compositions, which are incorporated into a polymeric matrix for use in capacitors, filters, and the like. A porous, generally spherical bead of hydrous metal oxide containing titanium or zirconium is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead may be washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) at elevated temperature and pressure to convert the bead into a mixed hydrous titanium- or zirconium-alkaline earth oxide while retaining the generally spherical shape. Alternatively, the gel bead may be made by coprecipitation. This mixed oxide bead is then washed, dried and calcined to produce the desired (BaTiO.sub.3, PbTiO.sub.3, SrZrO.sub.3) structure. The sintered beads are incorporated into a selected polymer matrix. The resulting dielectric composite material may be electrically "poled" if desired.

Dielectric composite materials and method for preparing

DOEpatents

Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.; Felten, John J.

2003-07-29

The invention allows the fabrication of small, dense beads of dielectric materials with selected compositions, which are incorporated into a polymeric matrix for use in capacitors, filters, and the like. A porous, generally spherical bead of hydrous metal oxide containing titanium or zirconium is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead may be washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) at elevated temperature and pressure to convert the bead into a mixed hydrous titanium- or zirconium-alkaline earth oxide while retaining the generally spherical shape. Alternatively, the gel bead may be made by coprecipitation. This mixed oxide bead is then washed, dried and calcined to produce the desired (BaTiO.sub.3, PbTiO.sub.3, SrZrO.sub.3) structure. The sintered beads are incorporated into a selected polymer matrix. The resulting dielectric composite material may be electrically "poled" if desired.

Superparamagnetic poly(methyl methacrylate) beads for nattokinase purification from fermentation broth.

PubMed

Yang, Chengli; Xing, Jianmin; Guan, Yueping; Liu, Huizhou

2006-09-01

An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods.

Stability optimization of microbial surface-enhanced Raman spectroscopy detection with immunomagnetic separation beads

NASA Astrophysics Data System (ADS)

Uusitalo, Sanna; Kögler, Martin; Välimaa, Anna-Liisa; Petäjä, Jarno; Kontturi, Ville; Siitonen, Samuli; Laitinen, Riitta; Kinnunen, Matti; Viitala, Tapani; Hiltunen, Jussi

2017-03-01

Immunomagnetic separation (IMS) beads with antibody coating are an interesting option for biosensing applications for the identification of biomolecules and biological cells, such as bacteria. The paramagnetic properties of the beads can be utilized with optical sensing by migrating and accumulating the beads and the bound analytes toward the focus depth of the detection system by an external magnetic field. The stability of microbial detection with IMS beads was studied by combining a flexible, inexpensive, and mass producible surface-enhanced Raman spectroscopy (SERS) platform with gold nanoparticle detection and antibody recognition by the IMS beads. Listeria innocua ATCC 33090 was used as a model sample and the effect of the IMS beads on the detected Raman signal was studied. The IMS beads were deposited into a hydrophobic sample well and accumulated toward the detection plane by a neodymium magnet. For the first time, it was shown that the spatial stability of the detection could be improved up to 35% by using IMS bead capture and sample well placing. The effect of a neodymium magnet under the SERS chip improved the temporal detection and significantly reduced the necessary time for sample stabilization for advanced laboratory testing.

Facile fabrication and characterization of a novel oral pH-sensitive drug delivery system based on CMC hydrogel and HNT-AT nanohybrid.

PubMed

Hossieni-Aghdam, Seyed Jamal; Foroughi-Nia, Behrouz; Zare-Akbari, Zhila; Mojarad-Jabali, Solmaz; Motasadizadeh, Hamidreza; Farhadnejad, Hassan

2018-02-01

The main aim of the present study was to design pH-sensitive bionanocomposite hydrogel beads based on CMC and HNT-AT nanohybrid and evaluate whether prepared bionanocomposite beads have the potential to be used in drug delivery applications. Atenolol (AT), as a model drug, was incorporated into the lumen of HA nanotubes via the co-precipitation technique. HNT/AT nanohybrid and CMC/HNT-AT beads were characterized via XRD, SEM, TGA, and FT-IR techniques. Drug loading and encapsulation efficiency was found to be high for CMC/HNT3 beads. Moreover, the swelling and drug release properties of the prepared CMC/HA-AT beads were investigated, and showed a pH sensitive swelling behavior with maximum its content at pH 6.8. Also, it was found that the swelling ratio of CMC/HNT beads was lower than that of pristine CMC beads. Drug release behavior of CMC/HNT-AT bionanocomposite hydrogel beads were investigated. A more sustained and controlled drug releases were observed for CMC/HNT-AT beads. Copyright © 2017 Elsevier B.V. All rights reserved.

The elution of colistimethate sodium from polymethylmethacrylate and calcium phosphate cement beads.

PubMed

Waterman, Paige; Barber, Melissa; Weintrob, Amy C; VanBrakle, Regina; Howard, Robin; Kozar, Michael P; Andersen, Romney; Wortmann, Glenn

2012-06-01

Gram-negative bacilli resistance to all antibiotics, except for colistimethate sodium (CMS), is an emerging healthcare concern. Incorporating CMS into orthopedic cement to treat bone and soft-tissue infections due to these bacteria is attractive, but the data regarding the elution of CMS from cement are conflicting. The in vitro analysis of the elution of CMS from polymethylmethacrylate (PMMA) and calcium phosphate (CP) cement beads is reported. PMMA and CP beads containing CMS were incubated in phosphate-buffered saline and the eluate sampled at sequential time points. The inhibition of the growth of a strain of Acinetobacter baumannii complex by the eluate was measured by disk diffusion and microbroth dilution assays, and the presence of CMS in the eluate was measured by mass spectroscopy. Bacterial growth was inhibited by the eluate from both PMMA and CP beads. Mass spectroscopy demonstrated greater elution of CMS from CP beads than PMMA beads. The dose of CMS in PMMA beads was limited by failure of bead integrity. CMS elutes from both CP and PMMA beads in amounts sufficient to inhibit bacterial growth in vitro. The clinical implications of these findings require further study.

Alginate Beads as Synthetic Inoculant Carriers for Slow Release of Bacteria That Affect Plant Growth †‡

PubMed Central

Bashan, Yoav

1986-01-01

Uniform synthetic beads were developed as carriers for the bacterial inoculation of plants. The beads are made of sodium alginate and skim milk and contain a large reservoir of bacterial culture which releases the bacteria at a slow and constant rate. The beads are biodegradable and produce no environmental pollution. The strength of the beads, the rate of bacterial release, and the time of their survival in the soil can be controlled by several hardening treatments. The final product, lyophilized beads, is simple to use and is applied to the seeds concomitantly with sowing. The released bacteria are available for root colonization immediately at seed germination. Dry beads containing bacteria can be stored at ambient temperature over a long period without loss of bacterial content; storage requires a limited space, and the quality control of a number of bacteria in the bead is simple. The level of plant inoculation with beads was similar to that with previously used peat inoculants, but the former method yielded more consistent results, as the frequency of inoculated plants was much higher. The former method provides a different approach for inoculation of plants with beneficial rhizosphere bacteria. Images PMID:16347055

A new efficient method of generating photoaffinity beads for drug target identification.

PubMed

Nishiya, Yoichi; Hamada, Tomoko; Abe, Masayuki; Takashima, Michio; Tsutsumi, Kyoko; Okawa, Katsuya

2017-02-15

Affinity purification is one of the most prevalent methods for the target identification of small molecules. Preparation of an appropriate chemical for immobilization, however, is a tedious and time-consuming process. A decade ago, a photoreaction method for generating affinity beads was reported, where compounds are mixed with agarose beads carrying a photoreactive group (aryldiazirine) and then irradiated with ultraviolet light under dry conditions to form covalent attachment. Although the method has proven useful for identifying drug targets, the beads suffer from inefficient ligand incorporation and tend to shrink and aggregate, which can cause nonspecific binding and low reproducibility. We therefore decided to craft affinity beads free from these shortcomings without compromising the ease of preparation. We herein report a modified method; first, a compound of interest is mixed with a crosslinker having an activated ester and a photoreactive moiety on each end. This mixture is then dried in a glass tube and irradiated with ultraviolet light. Finally, the conjugates are dissolved and reacted with agarose beads with a primary amine. This protocol enabled us to immobilize compounds more efficiently (approximately 500-fold per bead compared to the original method) and generated beads without physical deterioration. We herein demonstrated that the new FK506-immobilized beads specifically isolated more FKBP12 than the original beads, thereby proving our method to be applicable to target identification experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

The profile of adsorbed plasma and serum proteins on methacrylic acid copolymer beads: Effect on complement activation.

PubMed

Wells, Laura A; Guo, Hongbo; Emili, Andrew; Sefton, Michael V

2017-02-01

Polymer beads made of 45% methacrylic acid co methyl methacrylate (MAA beads) promote vascular regenerative responses in contrast to control materials without methacrylic acid (here polymethyl methacrylate beads, PMMA). In vitro and in vivo studies suggest that MAA copolymers induce differences in macrophage phenotype and polarization and inflammatory responses, presumably due to protein adsorption differences between the beads. To explore differences in protein adsorption in an unbiased manner, we used high resolution shotgun mass spectrometry to identify and compare proteins that adsorb from human plasma or serum onto MAA and PMMA beads. From plasma, MAA beads adsorbed many complement proteins, such as C1q, C4-related proteins and the complement inhibitor factor H, while PMMA adsorbed proteins, such as albumin, C3 and apolipoproteins. Because of the differences in complement protein adsorption, follow-up studies focused on using ELISA to assess complement activation. When incubated in serum, MAA beads generated significantly lower levels of soluble C5b9 and C3a/C3a desarg in comparison to PMMA beads, indicating a decrease in complement activation with MAA beads. The differences in adsorbed protein on the two materials likely alter subsequent cell-material interactions that ultimately result in different host responses and local vascularization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation of porous 2,3-dialdehyde cellulose beads crosslinked with chitosan and their application in adsorption of Congo red dye.

PubMed

Ruan, Chang-Qing; Strømme, Maria; Lindh, Jonas

2018-02-01

Micrometer sized 2,3-dialdehyde cellulose (DAC) beads were produced via a recently developed method relying on periodate oxidation of Cladophora nanocellulose. The produced dialdehyde groups and pristine hydroxyl groups provided the DAC beads with a vast potential for further functionalization. The sensitivity of the DAC beads to alkaline conditions, however, limits their possible functionalization and applications. Hence, alkaline-stable and porous cellulose beads were prepared via a reductive amination crosslinking reaction between 2,3-dialdehyde cellulose beads and chitosan. The produced materials were thoroughly characterized with different methods. The reaction conditions, including the amount of chitosan used, conditions for reductive amination, reaction temperature and time, were investigated and the maintained morphology of the beads after exposure to 1M NaOH (aq.) was verified with SEM. Different washing and drying procedures were used and the results were studied by SEM and BET analysis. Furthermore, FTIR, TGA, EDX, XPS, DLS and elemental analysis were performed to characterize the properties of the prepared beads. Finally, the alkaline-stable porous chitosan cross-linked 2,3-dialdehyde cellulose beads were applied as adsorbent for the dye Congo red. The crosslinked beads displayed fast and high adsorption capacity at pH 2 and good desorption properties at pH 12, providing a promising sorption material. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dispersion of fine phosphor particles by newly developed beads mill

NASA Astrophysics Data System (ADS)

Joni, I. Made; Panatarani, C.; Maulana, Dwindra W.

2016-02-01

Fine phosphor Y2O3:Eu3+ particles has advanced properties compare to conventional particles applied for compact fluorescent lamp (CFL) as three band phosphor. However, suspension of fine particles easily agglomerated during preparation of spray coating of the CFL tube. Therefore, it is introduced newly developed beads mill system to disperse fine phosphor. The beads mill consist of glass beads, dispersing chamber (impellers), separator chamber, slurry pump and motors. The first important performance of beads mill is the performance of the designed on separating the beads with the suspended fine particles. We report the development of beads mill and its separation performance vary in flow rate and separator rotation speeds. The 27 kg of glass beads with 30 µm in size was poured into dispersing chamber and then water was pumped continuously through the slurry pump. The samples for the separation test was obtained every 1 hours vary in rotation speed and slurry flow rate. The results shows that the separation performance was 99.99 % obtained for the rotation speed of >1000 rpm and flow rate of 8 L/minute. The performances of the system was verified by dispersing fine phosphor Y2O3:Eu3+ particles with concentration 1 wt.%. From the observed size distribution of particles after beads mill, it is concluded that the current design of bead mill effectively dispersed fine phosphor Y2O3:Eu3+.

Characterization of product capture resin during microbial cultivations.

PubMed

Frykman, Scott; Tsuruta, Hiroko; Galazzo, Jorge; Licari, Peter

2006-06-01

Various bioactive small molecules produced by microbial cultivation are degraded in the culture broth or may repress the formation of additional product. The inclusion of hydrophobic adsorber resin beads to capture these products in situ and remove them from the culture broth can reduce or prevent this degradation and repression. These product capture beads are often subjected to a dynamic and stressful microenvironment for a long cultivation time, affecting their physical structure and performance. Impact and collision forces can result in the fracturing of these beads into smaller pieces, which are difficult to recover at the end of a cultivation run. Various contaminating compounds may also bind in a non-specific manner to these beads, reducing the binding capacity of the resin for the product of interest (fouling). This study characterizes resin bead binding capacity (to monitor bead fouling), and resin bead volume distributions (to monitor bead fracture) for an XAD-16 adsorber resin used to capture epothilone produced during myxobacterial cultivations. Resin fouling was found to reduce the product binding capacity of the adsorber resin by 25-50%. Additionally, the degree of resin bead fracture was found to be dependent on the cultivation length and the impeller rotation rate. Microbial cultivations and harvesting processes should be designed in such a way to minimize bead fragmentation and fouling during cultivation to maximize the amount of resin and associated product harvested at the end of a run.

Inertial-ordering-assisted droplet microfluidics for high-throughput single-cell RNA-sequencing.

PubMed

Moon, Hui-Sung; Je, Kwanghwi; Min, Jae-Woong; Park, Donghyun; Han, Kyung-Yeon; Shin, Seung-Ho; Park, Woong-Yang; Yoo, Chang Eun; Kim, Shin-Hyun

2018-02-27

Single-cell RNA-seq reveals the cellular heterogeneity inherent in the population of cells, which is very important in many clinical and research applications. Recent advances in droplet microfluidics have achieved the automatic isolation, lysis, and labeling of single cells in droplet compartments without complex instrumentation. However, barcoding errors occurring in the cell encapsulation process because of the multiple-beads-in-droplet and insufficient throughput because of the low concentration of beads for avoiding multiple-beads-in-a-droplet remain important challenges for precise and efficient expression profiling of single cells. In this study, we developed a new droplet-based microfluidic platform that significantly improved the throughput while reducing barcoding errors through deterministic encapsulation of inertially ordered beads. Highly concentrated beads containing oligonucleotide barcodes were spontaneously ordered in a spiral channel by an inertial effect, which were in turn encapsulated in droplets one-by-one, while cells were simultaneously encapsulated in the droplets. The deterministic encapsulation of beads resulted in a high fraction of single-bead-in-a-droplet and rare multiple-beads-in-a-droplet although the bead concentration increased to 1000 μl -1 , which diminished barcoding errors and enabled accurate high-throughput barcoding. We successfully validated our device with single-cell RNA-seq. In addition, we found that multiple-beads-in-a-droplet, generated using a normal Drop-Seq device with a high concentration of beads, underestimated transcript numbers and overestimated cell numbers. This accurate high-throughput platform can expand the capability and practicality of Drop-Seq in single-cell analysis.

Development of hydrogel TentaGel shell-core beads for ultrahigh throughput solution-phase screening of encoded OBOC combinatorial small molecule libraries.

PubMed

Baek, Hyoung Gee; Liu, Ruiwu; Lam, Kit S

2009-01-01

The one-bead one-compound (OBOC) combinatorial library method enables the rapid generation and screening of millions of discrete chemical compounds on beads. Most of the OBOC screening methods require the library compounds to remain tethered to the bead during screening process. Methods have also been developed to release library compounds from immobilized beads for in situ solution phase or "lawn" assays. However, this latter approach, while extremely powerful, is severely limited by the lack of suitable solid supports for such assays. Here, we report on the development of a novel hydrogel TentaGel shell-core (HTSC) bead in which hydrogel is grafted onto the polystyrene-based TentaGel (TG) bead as an outer shell (5-80 mum thick) via free radical surface-initiated polymerization. This novel shell-core bilayer resin enables the preparation of encoded OBOC combinatorial small molecule libraries, such that the library compounds reside on the highly hydrophilic outer layer and the coding tags reside in the polystyrene-based TG core. Using fluorescein as a model small molecule compound, we have demonstrated that fluorescein molecules that have been linked covalently to the hydrogel shell via a disulfide bond could readily diffuse out of the hydrogel layer into the bead surrounding after reduction with dithiothreitol. In contrast, under identical condition, the released fluorescein molecules remained bound to unmodified TG bead. We have prepared an encoded OBOC small molecule library on the novel shell-core beads and demonstrated that the beads can be readily decoded.

Immobilized OBOC combinatorial bead array to facilitate multiplicative screening.

PubMed

Xiao, Wenwu; Bononi, Fernanda C; Townsend, Jared; Li, Yuanpei; Liu, Ruiwu; Lam, Kit S

2013-07-01

One-bead-one-compound (OBOC) combinatorial library screening has been broadly utilized for the last two decades to identify small molecules, peptides or peptidomimetics targeting variable screening probes such as cell surface receptors, bacteria, protein kinases, phosphatases, proteases etc. In previous screening methods, library beads were suspended in solution and screened against one single probe. Only the positive beads were tracked and isolated for additional screens and finally selected for chemical decoding. During this process, the remaining negative beads were not tracked and discarded. Here we report a novel bead immobilization method such that a bead library array can be conveniently prepared and screened in its entirety, sequentially many times with a series of distinct probes. This method not only allows us to increase the screening efficiency but also permits us to determine the binding profile of each and every library bead against a large number of target receptors. As proof of concept, we serially screened a random OBOC disulfide containing cyclic heptapeptide library with three water soluble dyes as model probes: malachite green, bromocresol purple and indigo carmine. This multiplicative screening approach resulted in a rapid determination of the binding profile of each and every bead respective to each of the three dyes. Beads that interacted with malachite green only, bromocresol purple only, or both indigo carmine and bromocresol purple were isolated, and their peptide sequences were determined with microsequencer. Ultimately, the novel OBOC multiplicative screening approach could play a key role in the enhancement of existing on-bead assays such as whole cell binding, bacteria binding, protein binding, posttranslational modifications etc. with increased efficiency, capacity, and specificity.

Fused Bead Analysis of Diogenite Meteorites

NASA Technical Reports Server (NTRS)

Mittlefehldt, D.W.; Beck, B.W.; McSween, H.Y.; Lee, C.T. A.

2009-01-01

Bulk rock chemistry is an essential dataset in meteoritics and planetary science [1]. A common method used to obtain the bulk chemistry of meteorites is ICP-MS. While the accuracy, precision and low detection limits of this process are advantageous [2], the sample size used for analysis (approx.70 mg) can be a problem in a field where small and finite samples are the norm. Fused bead analysis is another bulk rock analytical technique that has been used in meteoritics [3]. This technique involves forming a glass bead from 10 mg of sample and measuring its chemistry using a defocused beam on a microprobe. Though the ICP-MS has lower detection limits than the microprobe, the fused bead method destroys a much smaller sample of the meteorite. Fused bead analysis was initially designed for samples with near-eutectic compositions and low viscosities. Melts generated of this type homogenize at relatively low temperatures and produce primary melts near the sample s bulk composition [3]. The application of fused bead analysis to samples with noneutectic melt compositions has not been validated. The purpose of this study is to test if fused bead analysis can accurately determine the bulk rock chemistry of non-eutectic melt composition meteorites. To determine this, we conduct two examinations of the fused bead. First, we compare ICP-MS and fused bead results of the same samples using statistical analysis. Secondly, we inspect the beads for the presence of crystals and chemical heterogeneity. The presence of either of these would indicate incomplete melting and quenching of the bead.

A Functional Assay for GPR55: Envision Protocol.

PubMed

Anavi-Goffer, Sharon; Ross, Ruth A

2016-01-01

AlphaScreen(®) SureFire(®) assay is a novel technology that combines luminescent oxygen channeling technology, nano-beads, and monocloncal antibodies to detect the level of a selected protein in a volume lower than 5 μl. This method is more sensitive compared with the traditional enzyme-linked immunosorbent assays (ELISA), and can detect an increasing number of new targets. Here, we described a method for AlphaScreen(®) SureFire(®) assay that targets ERK1/2 phosphorylation, a primary downstream signaling pathway that conveys activation of GPR55 by L-α-lysophosphatidylinositol (LPI) and certain cannabinoids.

Wetting behavior on hexagonally close-packed polystyrene bead arrays with different topographies.

PubMed

Park, Yi-Seul; Yoon, Seo Young; Lee, Jin Seok

2016-01-21

Herein, we investigated the wetting behavior of hexagonally close-packed polystyrene bead arrays with different bead diameters and surface flatness. The contact angle was found to be influenced by the surface roughness as well as the contact area of the polystyrene bead array with a water droplet.

49 CFR 173.221 - Polymeric beads, expandable and Plastic molding compound.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Polymeric beads, expandable and Plastic molding... Than Class 1 and Class 7 § 173.221 Polymeric beads, expandable and Plastic molding compound. (a) Non-bulk shipments of Polymeric beads (or granules), expandable, evolving flammable vapor and Plastic...

49 CFR 173.221 - Polymeric beads, expandable and Plastic molding compound.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Polymeric beads, expandable and Plastic molding... Than Class 1 and Class 7 § 173.221 Polymeric beads, expandable and Plastic molding compound. (a) Non-bulk shipments of Polymeric beads (or granules), expandable, evolving flammable vapor and Plastic...

49 CFR 173.221 - Polymeric beads, expandable and Plastic molding compound.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Polymeric beads, expandable and Plastic molding... Than Class 1 and Class 7 § 173.221 Polymeric beads, expandable and Plastic molding compound. (a) Non-bulk shipments of Polymeric beads (or granules), expandable, evolving flammable vapor and Plastic...

49 CFR 173.221 - Polymeric beads, expandable and Plastic molding compound.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Polymeric beads, expandable and Plastic molding... Than Class 1 and Class 7 § 173.221 Polymeric beads, expandable and Plastic molding compound. (a) Non-bulk shipments of Polymeric beads (or granules), expandable evolving flammable vapor and Plastic...

49 CFR 173.221 - Polymeric beads, expandable and Plastic molding compound.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Polymeric beads, expandable and Plastic molding... Than Class 1 and Class 7 § 173.221 Polymeric beads, expandable and Plastic molding compound. (a) Non-bulk shipments of Polymeric beads (or granules), expandable evolving flammable vapor and Plastic...

Identification of cancer specific ligands from one-bead one compound combinatorial libraries to develop theranostics agents against oral squamous cell carcinoma

NASA Astrophysics Data System (ADS)

Yang, Frances Fan

Background: Oral squamous cell carcinoma (OSCC) is one of the most prevalent disease worldwide. One-bead one-compound (OBOC) combinatorial technology is a powerful method to identify peptidomimetic ligands against a variety of receptors on cell surfaces. We therefore hypothesized that cancer specific ligands against OSCC might be identified and can be conjugated to optical dyes or nanocarriers to develop theranostic agents against OSCC. Material and methods: Different OSCC cell lines were incubated with OBOC libraries and beads with cell binding were sorted and then screened with normal human cells to identify peptide-beads binding to different OSCC cell lines but not binding to normal human cells. The molecular probes of OSCC were developed by biotinylating the carboxyl end of the ligands. OSCC theranostic agents were developed by decorating LLY13 with NPs and evaluated by using orthotopic bioluminescent oral cancer model. Results: Six OSCC specific ligands were discovered. Initial peptide-histochemistry study indicated that LLY12 and LLY13 were able to specifically detect OSCC cells grown on chamber slides at the concentration of 1 muM. In addition, LLY13 was found to penetrate into the OSCC cells and accumulate in the cytoplasm, and nucleus. After screened with a panel of integrin antibodies, only anti-alpha3 antibody was able to block most of OSCC cells binding to the LLY13 beads. OSCC theranostic agents developed using targeting LLY13 micelles (25+/- 4nm in diameter) were more efficient in binding to HSC-3 cancer cells compared to non-targeting micelles. Ex vivo images demonstrated that xenografts from the mice with targeting micelles appeared to have higher signals than the non-targeting groups. Conclusion: LLY13 has promising in vitro and in vivo targeting activity against OSCC. In addition, LLY13 is also able to penetrate into cancer cells via endocytosis. Initial study indicated that alpha3 integrin might partially be the corresponding receptor involved for LLY13's binding to oral cancer cells. OSCC ligands developed from this study may become potential candidates for the development of OSCC targeted theranostic agents.

Shocked and Stressed, Metals Get Stronger

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hackel, L

2002-03-12

People who know their way around metalworking are no doubt familiar with peening--using a ball-peen hammer to pound a piece of metal into shape and strengthen it against fatigue failure. For the past 50 years, an industrialized equivalent has been shot peening, in which metal or ceramic beads as large as marbles or as small as salt and pepper grains pneumatically bombard a metal surface. Laser peening, a process based on a superior laser technology developed at Lawrence Livermore, replaces the hammer blows and streams of beads with short blasts of laser light. The end result is a piece ofmore » metal with significantly improved performance. Lawrence Livermore and Metal Improvement Company, Inc., won a coveted R and D 100 Award for their laser-peening process in 1998 (see S and TR, October 1998, pp. 12-13). Since that time, they've been developing uses for the technology with a number of industries, including automotive, medical, and aerospace. They've also developed an offshoot technique--laser peenmarking{trademark}--which provides a way to easily and clearly identify parts with a mark that is extremely difficult to counterfeit. Another outgrowth is a new peen-forming technology that allows complex contouring of problematic thick metal components such as the thick sections of large aircraft wings. There have also been spinback applications to the Department of Energy's programs for stockpile stewardship, fuel-efficient vehicles, and long-term nuclear waste storage.« less

Incorporating Aptamers in the Multiple Analyte Profiling Assays (xMAP): Detection of C-Reactive Protein.

PubMed

Bernard, Elyse D; Nguyen, Kathy C; DeRosa, Maria C; Tayabali, Azam F; Aranda-Rodriguez, Rocio

2017-01-01

Aptamers are short oligonucleotide sequences used in detection systems because of their high affinity binding to a variety of macromolecules. With the introduction of aptamers over 25 years ago came the exploration of their use in many different applications as a substitute for antibodies. Aptamers have several advantages; they are easy to synthesize, can bind to analytes for which it is difficult to obtain antibodies, and in some cases bind better than antibodies. As such, aptamer applications have significantly expanded as an adjunct to a variety of different immunoassay designs. The Multiple-Analyte Profiling (xMAP) technology developed by Luminex Corporation commonly uses antibodies for the detection of analytes in small sample volumes through the use of fluorescently coded microbeads. This technology permits the simultaneous detection of multiple analytes in each sample tested and hence could be applied in many research fields. Although little work has been performed adapting this technology for use with apatmers, optimizing aptamer-based xMAP assays would dramatically increase the versatility of analyte detection. We report herein on the development of an xMAP bead-based aptamer/antibody sandwich assay for a biomarker of inflammation (C-reactive protein or CRP). Protocols for the coupling of aptamers to xMAP beads, validation of coupling, and for an aptamer/antibody sandwich-type assay for CRP are detailed. The optimized conditions, protocols and findings described in this research could serve as a starting point for the development of new aptamer-based xMAP assays.

Induced movement of the magnetic beads and DNA-based dumbbell in a micro fluidic channel

NASA Astrophysics Data System (ADS)

Babić, B.; Ghai, R.; Dimitrov, K.

2007-12-01

We have explored controlled movement of magnetic beads and a dumbbell structure composed of DNA, a magnetic and a non-magnetic bead in a micro fluidic channel. Movement of the beads and dumbbells is simulated assuming that a net force is described as a superposition between the magnetic and hydrodynamic drag forces. Trajectories of beads and dumbbells are observed with optical light microscopy. The experimentally measured data show a good agreement with the simulations. This dynamical approach offers the prospect to stretch the DNA within the dumbbell and investigate its conformational changes. Further on, we demonstrate that short sonication can reduce multiple attachments of DNA to the beads.

A Controlled Drug-Delivery Experiment Using Alginate Beads

ERIC Educational Resources Information Center

Farrell, Stephanie; Vernengo, Jennifer

2012-01-01

This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

Degradation of synthetic pollutants in real wastewater using laccase encapsulated in core-shell magnetic copper alginate beads.

PubMed

Le, Thao Thanh; Murugesan, Kumarasamy; Lee, Chung-Seop; Vu, Chi Huong; Chang, Yoon-Seok; Jeon, Jong-Rok

2016-09-01

Immobilization of laccase has been highlighted to enhance their stability and reusability in bioremediation. In this study, we provide a novel immobilization technique that is very suitable to real wastewater treatment. A perfect core-shell system composing copper alginate for the immobilization of laccase (Lac-beads) was produced. Additionally, nFe2O3 was incorporated for the bead recycling through magnetic force. The beads were proven to immobilize 85.5% of total laccase treated and also to be structurally stable in water, acetate buffer, and real wastewater. To test the Lac-beads reactivity, triclosan (TCS) and Remazol Brilliant Blue R (RBBR) were employed. The Lac-beads showed a high percentage of TCS removal (89.6%) after 8h and RBBR decolonization at a range from 54.2% to 75.8% after 4h. Remarkably, the pollutants removal efficacy of the Lac-beads was significantly maintained in real wastewater with the bead recyclability, whereas that of the corresponding free laccase was severely deteriorated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microfluidic Bead Suspension Hopper

PubMed Central

2014-01-01

Many high-throughput analytical platforms, from next-generation DNA sequencing to drug discovery, rely on beads as carriers of molecular diversity. Microfluidic systems are ideally suited to handle and analyze such bead libraries with high precision and at minute volume scales; however, the challenge of introducing bead suspensions into devices before they sediment usually confounds microfluidic handling and analysis. We developed a bead suspension hopper that exploits sedimentation to load beads into a microfluidic droplet generator. A suspension hopper continuously delivered synthesis resin beads (17 μm diameter, 112,000 over 2.67 h) functionalized with a photolabile linker and pepstatin A into picoliter-scale droplets of an HIV-1 protease activity assay to model ultraminiaturized compound screening. Likewise, trypsinogen template DNA-coated magnetic beads (2.8 μm diameter, 176,000 over 5.5 h) were loaded into droplets of an in vitro transcription/translation system to model a protein evolution experiment. The suspension hopper should effectively remove any barriers to using suspensions as sample inputs, paving the way for microfluidic automation to replace robotic library distribution. PMID:24761972

In vivo cleansing efficacy of biodegradable exfoliating beads assessed by skin bioengineering techniques.

PubMed

Kitsongsermthon, J; Duangweang, K; Kreepoke, J; Tansirikongkol, A

2017-11-01

The plastic microbeads, used in many cleansers, will be banned in cosmetic and personal care products within 2017 since they are non-degradable and can disturb the living organisms in water reservoirs. Various choices of biodegradable beads are commercially available, but their efficacy has not been proven yet. This study aimed to compare the cleansing efficacy in dirt and sebum removal aspects of three types of exfoliating beads. The gel scrubs with polyethylene (PE) beads, mannan beads or wax beads, were formulated and evaluated for their stability. The in vivo evaluation was done in 38 healthy volunteers and the skin irritation, efficacy for dirt and sebum removal were measured by Mexameter ® , Colorimeter ® , and Sebumeter ® , respectively. The selected gel scrubs did not cause an irritation in any volunteers. The differences in dirt residues between before and after scrubbing were not statistically significant among three gel scrubs and the similar result was also reported in the sebum removal study. All gel scrubs demonstrated the comparable cleansing efficacy in term of dirt and sebum removal. Thus, mannan beads and wax beads may be replaced non-biodegradable PE beads to achieve the similar cleansing effect. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Development of bioactive porous α-TCP/HAp beads for bone tissue engineering.

PubMed

Asaoka, Teruo; Ohtake, Shoji; Furukawa, Katsuko S; Tamura, Akito; Ushida, Takashi

2013-11-01

Porous beads of bioactive ceramics such as hydroxyapatite (HAp) and tribasic calcium phosphate (TCP) are considered a promising scaffold for cultivating bone cells. To realize this, α-TCP/HAp functionally graded porous beads are fabricated with two main purposes: to maintain the function of the scaffold with sufficient strength up to the growth of new bone, and is absorbed completely after the growth. HAp is a bioactive material that has both high strength and strong tissue-adhesive properties, but is not readily absorbed by the human body. On the contrary, α-TCP is highly bioabsorbable, resulting in a scaffold that is absorbed before it is completely replaced by bone. In this study, we produced porous, bead-shaped carriers as scaffolds for osteoblast culture. To control the solubility in vivo, the fabricated beads contained α-TCP at the center and HAp at the surface. Cell adaptability of these beads for bone tissue engineering was confirmed in vitro. It was found that α-TCP/HAp bead carriers exhibit low toxicity in the initial stages of cell seeding and cell adhesion. The presence of HAp in the composite bead form effectively increased ALP activity. In conclusion, it is suggested that these newly developed α-TCP/HAp beads are a promising tool for bone tissue engineering. Copyright © 2013 Wiley Periodicals, Inc.

Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

PubMed

Ng, Choong Hey; Yang, Kun-Lin

2016-01-01

Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. Copyright © 2015 Elsevier Inc. All rights reserved.

Microfabricated Renewable Beads-Trapping/Releasing Flow Cell for Rapid Antigen-Antibody Reaction in Chemiluminescent Immunoassay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Zhifeng; Shao, Guocheng; Wang, Jun

2011-04-01

A filter pillar-array microstructure was coupled with a pneumatic micro-valve to fabricate a reusable miniaturized beads-trapping/releasing flow cell, in which trapping and releasing beads can be conveniently realized by switching the micro-valve. This miniaturized device was suitable to construct automatic fluidic system for “renewable surface analysis”. The renewable surface strategy based on pneumatic micro-valve enabled capture of beads in beads chamber prior to each assay, and release of the used beads after the assay. Chemiluminescent competitive immunoassay of 3,5,6-trichloropyridinol (TCP) was performed as a model to demonstrate the application potential of this reusable miniaturized flow cell. The whole fluidic assaymore » process including beads trapping, immuno-binding, beads washing, beads releasing and signal collection could be completed in 10 min. Immunoassay of TCP using this miniaturized device showed a linear range of 0.20-70 ng/mL with a limit of detection of 0.080 ng/mL. The device had been successfully used for detection of TCP spiked in rat serum with average recovery of 97%. This investigation provides a rapid, sensitive, reusable, low-cost and automatic miniaturized device for solid-phase biochemical analysis for various purposes.« less

Orbeez: the magic water absorbing bead--risk of pediatric bowel obstruction?

PubMed

Darracq, Michael A; Cullen, Jennifer; Rentmeester, Landen; Cantrell, F Lee; Ly, Binh T

2015-06-01

In December 2012, the U.S. Consumer Product Safety Commission recalled the water-absorbing toy WaterBalz after reports of small intestine obstruction after ingestion by children. Orbeez, another water-absorbing bead, remains available and is marketed as a children's toy. We sought to determine the extent to which Orbeez enlarge in various liquid media and the potential risk for bowel obstruction. Three Orbeez beads were added to 210 mL of the following liquid media: room temperature tap water, whole milk, simulated gastric fluid, GoLytely (polyethelyelene glycol, 3350 and electrolytes), and vodka (40% ethanol by volume). Diameters before exposure to media were measured using a caliper to the nearest 0.1 mm and again at 1, 2, 4, 6, 12, and 24 hours. Ten beads were then added to the beads already immersed in simulated gastric fluid and water and observed for an additional 72 hours (96 hours total) for clumping or increase in diameter. Clumping was defined as two or more beads remaining persistently adherent to one another despite gentle circular movement (swirling) of the liquid. Growth in each of the media was observed. Growth in simulated gastric fluid was minimal, whereas the beads were observed to be the largest after 24 hours in vodka. Clumping of the beads was not observed to occur. Orbeez beads enlarge to a different extent in different liquid media. It is unlikely that Orbeez beads would expand to sizes or demonstrate clumping that would be concerning for intestinal obstruction.

Capturing and concentrating adenovirus using magnetic anionic nanobeads

PubMed Central

Sakudo, Akikazu; Baba, Koichi; Ikuta, Kazuyoshi

2016-01-01

We recently demonstrated how various enveloped viruses can be efficiently concentrated using magnetic beads coated with an anionic polymer, poly(methyl vinyl ether-maleic anhydrate). However, the exact mechanism of interaction between the virus particles and anionic beads remains unclear. To further investigate whether these magnetic anionic beads specifically bind to the viral envelope, we examined their potential interaction with a nonenveloped virus (adenovirus). The beads were incubated with either adenovirus-infected cell culture medium or nasal aspirates from adenovirus-infected individuals and then separated from the supernatant by applying a magnetic field. After thoroughly washing the beads, adsorption of adenovirus was confirmed by a variety of techniques, including immunochromatography, polymerase chain reaction, Western blotting, and cell culture infection assays. These detection methods positively identified the hexon and penton capsid proteins of adenovirus along with the viral genome on the magnetic beads. Furthermore, various types of adenovirus including Types 5, 6, 11, 19, and 41 were captured using the magnetic bead procedure. Our bead capture method was also found to increase the sensitivity of viral detection. Adenovirus below the detectable limit for immunochromatography was efficiently concentrated using the magnetic bead procedure, allowing the virus to be successfully detected using this methodology. Moreover, these findings clearly demonstrate that a viral envelope is not required for binding to the anionic magnetic beads. Taken together, our results show that this capture procedure increases the sensitivity of detection of adenovirus and would, therefore, be a valuable tool for analyzing both clinical and experimental samples. PMID:27274228

Pooling of Immunomagnetic Separation Beads Does Not Affect Detection Sensitivity of Six Major Serogroups of Shiga Toxin-Producing Escherichia coli in Cattle Feces.

PubMed

Noll, Lance W; Baumgartner, William C; Shridhar, Pragathi B; Cull, Charley A; Dewsbury, Diana M; Shi, Xiaorong; Cernicchiaro, Natalia; Renter, David G; Nagaraja, T G

2016-01-01

Shiga toxin-producing Escherichia coli (STEC) of the serogroups O26, O45, O103, O111, O121, and O145, often called non-O157 STEC, are foodborne pathogens. Cattle are asymptomatic reservoirs for STEC; the organisms reside in the hindgut and are shed in the feces, which serve as the source of food product contaminations. Culture-based detection of non-O157 STEC involves an immunomagnetic separation (IMS) step to capture the specific serogroups in complex matrices, such as feces. The IMS procedure is time consuming and labor intensive because of the need to subject each fecal sample to six individual beads. Therefore, our objective was to evaluate whether pooling of IMS beads affects sensitivity of non-O157 STEC detection compared with using individual IMS beads. The evaluation was done by comparing detection of serogroups in feces spiked with pure cultures (experiments 1 and 2) and from feces (n = 384) of naturally shedding cattle (experiment 3). In spiked fecal samples, detection with pools of three, four, six, or seven beads was similar to, or at times higher than, detection with individual IMS beads. In experiment 3, the proportions of fecal samples that tested positive for the six serogroups as detected by individual or pooled beads were similar. Based on noninferiority tests, detection with pooled beads was not substantially inferior to detection with individual beads (P > 0.05). In conclusion, the pooling of IMS beads is a better option for detection of STEC serogroups in fecal samples compared with individual beads because the procedure saves time and labor and has the prospect of a higher throughput.

Effect of Heat Input on Geometry of Austenitic Stainless Steel Weld Bead on Low Carbon Steel

NASA Astrophysics Data System (ADS)

Saha, Manas Kumar; Hazra, Ritesh; Mondal, Ajit; Das, Santanu

2018-05-01

Among different weld cladding processes, gas metal arc welding (GMAW) cladding becomes a cost effective, user friendly, versatile method for protecting the surface of relatively lower grade structural steels from corrosion and/or erosion wear by depositing high grade stainless steels onto them. The quality of cladding largely depends upon the bead geometry of the weldment deposited. Weld bead geometry parameters, like bead width, reinforcement height, depth of penetration, and ratios like reinforcement form factor (RFF) and penetration shape factor (PSF) determine the quality of the weld bead geometry. Various process parameters of gas metal arc welding like heat input, current, voltage, arc travel speed, mode of metal transfer, etc. influence formation of bead geometry. In the current experimental investigation, austenite stainless steel (316) weld beads are formed on low alloy structural steel (E350) by GMAW using 100% CO2 as the shielding gas. Different combinations of current, voltage and arc travel speed are chosen so that heat input increases from 0.35 to 0.75 kJ/mm. Nine number of weld beads are deposited and replicated twice. The observations show that weld bead width increases linearly with increase in heat input, whereas reinforcement height and depth of penetration do not increase with increase in heat input. Regression analysis is done to establish the relationship between heat input and different geometrical parameters of weld bead. The regression models developed agrees well with the experimental data. Within the domain of the present experiment, it is observed that at higher heat input, the weld bead gets wider having little change in penetration and reinforcement; therefore, higher heat input may be recommended for austenitic stainless steel cladding on low alloy steel.

Small Versus Large-Sized Drug-Eluting Beads (DEBIRI) for the Treatment of Hepatic Colorectal Metastases: A Propensity Score Matching Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akinwande, Olaguoke K., E-mail: gokeakin@gmail.com; Philips, Prejesh, E-mail: prejesh.philips@louisville.edu; Duras, Petr, E-mail: durasp@seznam.cz

2015-04-15

PurposeTo compare the feasibility, safety, and efficacy with small and large irinotecan drug-eluting beads (DEBIRI) for treating hepatic colorectal metastases.MethodsUsing our prospectively maintained, multi-center, intra-arterial therapy registry, we identified 196 patients treated with a combination of large beads (100–300 to 500–700 μm) and patients treated with a combination of small beads (70–150 to 100–300 μm). To minimize selection bias, a propensity score analysis was performed to compare both groups.ResultsUnadjusted analysis consisted of 196 and 30 patients treated with large and small beads, respectively. The adjusted analysis consisted of 19 patients each. Unadjusted analysis showed decreased all-grade (p = <0.001) and high-grade adverse effects (p = 0.02)more » in the small bead group, with a persisting trend toward decreased overall side effects in the adjusted analysis favoring small beads (p = 0.09) The adjusted analysis showed the percentage dose delivered (delivered dose/intended dose) was significantly greater in the small bead group compared to the large bead group (96 vs 79 %; p = 0.005). There were also a lower percentage of treatments terminating in complete stasis in the adjusted analysis (0.0035). Adjusted analysis also showed increased objective response rate (ORR) at 12 months (p = 0.04), with a corresponding trend also seen in the unadjusted analysis (0.09).ConclusionSmaller beads result in increased dose delivery probably due to less propensity to reach complete stasis. It may also lead to more durable long-term efficacy. Smaller beads also demonstrate similarly low toxicity compared to large-sized beads with a trend toward less toxicity.« less

Jeffamine derivatized TentaGel beads and poly(dimethylsiloxane) microbead cassettes for ultrahigh-throughput in situ releasable solution-phase cell-based screening of one-bead-one-compound combinatorial small molecule libraries.

PubMed

Townsend, Jared B; Shaheen, Farzana; Liu, Ruiwu; Lam, Kit S

2010-09-13

A method to efficiently immobilize and partition large quantities of microbeads in an array format in microfabricated poly(dimethylsiloxane) (PDMS) cassette for ultrahigh-throughput in situ releasable solution-phase cell-based screening of one-bead-one-compound (OBOC) combinatorial libraries is described. Commercially available Jeffamine triamine T-403 (∼440 Da) was derivatized such that two of its amino groups were protected by Fmoc and the remaining amino group capped with succinic anhydride to generate a carboxyl group. This resulting trifunctional hydrophilic polymer was then sequentially coupled two times to the outer layer of topologically segregated bilayer TentaGel (TG) beads with solid phase peptide synthesis chemistry resulting in beads with increased loading capacity, hydrophilicity, and porosity at the outer layer. We have found that such bead configuration can facilitate ultrahigh-throughput in situ releasable solution-phase screening of OBOC libraries. An encoded releasable OBOC small molecule library was constructed on Jeffamine derivatized TG beads with library compounds tethered to the outer layer via a disulfide linker and coding tags in the interior of the beads. Compound-beads could be efficiently loaded (5-10 min) into a 5 cm diameter Petri dish containing a 10,000-well PDMS microbead cassette, such that over 90% of the microwells were each filled with only one compound-bead. Jurkat T-lymphoid cancer cells suspended in Matrigel were then layered over the microbead cassette to immobilize the compound-beads. After 24 h of incubation at 37 °C, dithiothreitol was added to trigger the release of library compounds. Forty-eight hours later, MTT reporter assay was used to identify regions of reduced cell viability surrounding each positive bead. From a total of about 20,000 beads screened, 3 positive beads were detected and physically isolated for decoding. A strong consensus motif was identified for these three positive compounds. These compounds were resynthesized and found to be cytotoxic (IC(50) 50-150 μM) against two T-lymphoma cell lines and less so against the MDA-MB 231 breast cancer cell line. This novel ultrahigh-throughput OBOC releasable method can potentially be adapted to many existing 96- or 384-well solution-phase cell-based or biochemical assays.

Incorporation of beads into oral films for buccal and oral delivery of bioactive molecules.

PubMed

Castro, Pedro M; Sousa, Flávia; Magalhães, Rui; Ruiz-Henestrosa, Victor Manuel Pizones; Pilosof, Ana M R; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Manuela E

2018-08-15

The association of alginate beads and guar-gum films in a single delivery system was idealized to promote a more effective buccal and oral delivery of bioactive molecules. A response surface method (experimental design approach) was performed to obtain optimal formulations of alginate beads to be incorporated into guar gum oral films as combined buccal and oral delivery systems for caffeine delivery. The combined formulation was further characterized regarding physicochemical properties, drug release, cell viability and buccal permeability. Beads average size, determined by dynamic light scattering (DLS), was of 3.37 ± 6.36 μm. Film thickness was set to 62 μm. Scanning electron microscopy micrographs revealed that beads were evenly distributed onto the film matrix and beads size was in accordance to data obtained from DLS analysis. Evaluation of Fourier-transform infrared spectra did not indicate the formation of new covalent bonds between the matrix of guar-gum films, alginate beads and caffeine. In vitro release assays by dialysis membrane allowed understanding that the combination of guar-gum films and alginate beads assure a slower release of caffeine when compared with the delivery profile of free caffeine from alginate beads or guar-gum films alone. MTT assay, performed on human buccal carcinoma TR146 cell line, allowed concluding that neither guar-gum film, alginate beads nor guar-gum film incorporated into alginate beads significantly compromised cell viability after 12 h of exposure. As demonstrated by in vitro permeability assay using TR146 human buccal carcinoma cell lines, combination of guar-gum films and alginate beads also promoted a slower release and, thus, lower apparent permeability (1.15E-05 ± 3.50E-06) than for caffeine solution (2.68E-05 ± 7.30E-06), guar-gum film (3.12E-05 ± 4.70E-06) or alginate beads (2.01E-05 ± 3.90E-06). The conjugation of alginate beads within an orodispersible film matrix represents an effective oral/buccal delivery system that induces a controlled release along with an enhanced intimate contact with cell layers that may promote higher in vivo bioavailability of carried drugs. Copyright © 2018. Published by Elsevier Ltd.

75 FR 68377 - Notice of Inventory Completion: Anthropological Studies Center, Archaeological Collections...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-05

... basalt tool, 317 non-human bone fragments, 1 abalone shell fragment, 2 ash/soil samples, 1 groundstone, 1 quartz chunk, 3 abalone pendants and 4 olivella beads. One of the burials identified was associated with... groundstones, 2 steatite beads, 1 abalone pendant, 2 clamshell disk beads, 23 olivella beads and 2 steatite...

COMPARATIVE EVALUATION OF R3f GARNET BEAD FILTRATION AND MULTIMEDIA FILTRATION SYSTEMS; FINAL REPORT

EPA Science Inventory

This report summarizes the results of tests conducted to date at the EPA T&E Facility on the R3f filtration system utilizing fine beads (such as garnet beads or glass beads) and a conventional multimedia filtration system. Both systems have been designed and built by Enprotec, a...

Computer-aided diagnostic detection system of venous beading in retinal images

NASA Astrophysics Data System (ADS)

Yang, Ching-Wen; Ma, DyeJyun; Chao, ShuennChing; Wang, ChuinMu; Wen, Chia-Hsien; Lo, ChienShun; Chung, Pau-Choo; Chang, Chein-I.

2000-05-01

The detection of venous beading in retinal images provides an early sign of diabetic retinopathy and plays an important role as a preprocessing step in diagnosing ocular diseases. We present a computer-aided diagnostic system to automatically detect venous beading of blood vessels. It comprises of two modules, referred to as the blood vessel extraction module and the venus beading detection module. The former uses a bell-shaped Gaussian kernel with 12 azimuths to extract blood vessels while the latter applies a neural network-based shape cognitron to detect venous beading among the extracted blood vessels for diagnosis. Both modules are fully computer-automated. To evaluate the proposed system, 61 retinal images (32 beaded and 29 normal images) are used for performance evaluation.

Fluorescence lifetime endoscopy using TCSPC for the measurement of FRET in live cells

PubMed Central

Fruhwirth, Gilbert O.; Ameer-Beg, Simon; Cook, Richard; Watson, Timothy; Ng, Tony; Festy, Frederic

2010-01-01

Development of remote imaging for diagnostic purposes has progressed dramatically since endoscopy began in the 1960’s. The recent advent of a clinically licensed intensity-based fluorescence micro-endoscopic instrument has offered the prospect of real-time cellular resolution imaging. However, interrogating protein-protein interactions deep inside living tissue requires precise fluorescence lifetime measurements to derive the Förster resonance energy transfer between two tagged fluorescent markers. We developed a new instrument combining remote fiber endoscopic cellular-resolution imaging with TCSPC-FLIM technology to interrogate and discriminate mixed fluorochrome labeled beads and expressible GFP/TagRFP tags within live cells. Endoscopic-FLIM (e-FLIM) data was validated by comparison with data acquired via conventional FLIM and e-FLIM was found to be accurate for both bright bead and dim live cell samples. The fiber based micro-endoscope allowed remote imaging of 4 µm and 10 µm beads within a thick Matrigel matrix with confident fluorophore discrimination using lifetime information. More importantly, this new technique enabled us to reliably measure protein-protein interactions in live cells embedded in a 3D matrix, as demonstrated by the dimerization of the fluorescent protein-tagged membrane receptor CXCR4. This cell-based application successfully demonstrated the suitability and great potential of this new technique for in vivo pre-clinical biomedical and possibly human clinical applications. PMID:20588974

Evolution of a mass spectrometry-grade protease with PTM-directed specificity.

PubMed

Tran, Duc T; Cavett, Valerie J; Dang, Vuong Q; Torres, Héctor L; Paegel, Brian M

2016-12-20

Mapping posttranslational modifications (PTMs), which diversely modulate biological functions, represents a significant analytical challenge. The centerpiece technology for PTM site identification, mass spectrometry (MS), requires proteolytic cleavage in the vicinity of a PTM to yield peptides for sequencing. This requirement catalyzed our efforts to evolve MS-grade mutant PTM-directed proteases. Citrulline, a PTM implicated in epigenetic and immunological function, made an ideal first target, because citrullination eliminates arginyl tryptic sites. Bead-displayed trypsin mutant genes were translated in droplets, the mutant proteases were challenged to cleave bead-bound fluorogenic probes of citrulline-dependent proteolysis, and the resultant beads (1.3 million) were screened. The most promising mutant efficiently catalyzed citrulline-dependent peptide bond cleavage (k cat /K M = 6.9 × 10 5 M -1 ⋅s -1 ). The resulting C-terminally citrullinated peptides generated characteristic isotopic patterns in MALDI-TOF MS, and both a fragmentation product y 1 ion corresponding to citrulline (176.1030 m/z) and diagnostic peak pairs in the extracted ion chromatograms of LC-MS/MS analysis. Using these signatures, we identified citrullination sites in protein arginine deiminase 4 (12 sites) and in fibrinogen (25 sites, two previously unknown). The unique mass spectral features of PTM-dependent proteolytic digest products promise a generalized PTM site-mapping strategy based on a toolbox of such mutant proteases, which are now accessible by laboratory evolution.

How to fabricate robust microfluidic systems for a dollar

NASA Astrophysics Data System (ADS)

Lapierre, Florian; Cameron, Neil R.; Oakeshott, John; Peat, Thomas; Zhu, Yonggang

2013-12-01

Since the past decade, the interest towards microfluidic devices has sensibly grown due to the wide variety of multidisciplinary applications. One branch of the microfluidic domain consists in the synthesis of various types of emulsions requested by cosmetic, food and biotechnological industries In particular, monodisperse water-in-oil microemulsion synthetised in microfluidic devices are quickly becoming the new generation of emulsions for precise bead control and high surface area. These microemulsions are generally aqueous bioreactors in the form of droplets from 500 nm to 10 μm in diameter, enclosed in an oil environment. An increasing demand for bigger emulsions has led us to investigate new techniques for fabricating fluidic devices allowing a better control over the final size of the droplets. An easy, cheap, reproducible and fast technology for generating emulsions in the range of 100s μm with high throughout (up to mL/h) is reported. Simply using pipette tips and tubing, an innovative microfluidic device was fabricated, able to synthetise water-in-oil emulsions within the range 50 - 500 _μm and double emulsions. These new emulsions are currently used for the synthesis of highly porous polymers beads from High Internal Phase Emulsion (HIPE). These beads will find high potential in 3D cell culture due to their high porosity (up to 90%) and pore size (from 5 to 30μm).

Polyelectrolyte-coated ion exchangers for cell-resistant expanded bed adsorption.

PubMed

Dainiak, Maria B; Galaev, Igor Yu; Mattiasson, Bo

2002-01-01

Adsorption chromatography in expanded beds is a widely used technology for direct capture of target proteins from fermentation broths. However, in many cases this method cannot be applied as a result of the strong tendency of cells or cell debris to interact with the adsorbent beads. To prevent contamination of the expanded bed with the biomass, STREAMLINE DEAE, anion exchanger designed for expanded bed adsorption, was modified with a layer of poly(acrylic acid) (PAA). The shielding layer of polyelectrolyte was attached to the surface of the matrix beads via electrostatic interactions. PAA with a high degree of polymerization was chosen to prevent diffusion of large polymer molecules into the pores of adsorbent. Thus, the shielding layer of PAA was adsorbed only at the mouth of the pores of STREAMLINE DEAE beads and only marginally decreased the binding capacity of the ion exchanger for bovine serum albumin, the model protein in this study. PAA-coated STREAMLINE DEAE practically did not interact with yeast cells, which otherwise bound strongly to the native adsorbent at neutral conditions. Cell-resistant PAA-coated anion exchanger was successfully used for isolation of BSA from the model protein mixture containing BSA, lysozyme (positively charged at applied conditions), and yeast cells. The layer of PAA was stable under mild elution conditions, and the modified adsorbent could be used in the repeated purification cycles.

Generalization of the normal-exponential model: exploration of a more accurate parametrisation for the signal distribution on Illumina BeadArrays.

PubMed

Plancade, Sandra; Rozenholc, Yves; Lund, Eiliv

2012-12-11

Illumina BeadArray technology includes non specific negative control features that allow a precise estimation of the background noise. As an alternative to the background subtraction proposed in BeadStudio which leads to an important loss of information by generating negative values, a background correction method modeling the observed intensities as the sum of the exponentially distributed signal and normally distributed noise has been developed. Nevertheless, Wang and Ye (2012) display a kernel-based estimator of the signal distribution on Illumina BeadArrays and suggest that a gamma distribution would represent a better modeling of the signal density. Hence, the normal-exponential modeling may not be appropriate for Illumina data and background corrections derived from this model may lead to wrong estimation. We propose a more flexible modeling based on a gamma distributed signal and a normal distributed background noise and develop the associated background correction, implemented in the R-package NormalGamma. Our model proves to be markedly more accurate to model Illumina BeadArrays: on the one hand, it is shown on two types of Illumina BeadChips that this model offers a more correct fit of the observed intensities. On the other hand, the comparison of the operating characteristics of several background correction procedures on spike-in and on normal-gamma simulated data shows high similarities, reinforcing the validation of the normal-gamma modeling. The performance of the background corrections based on the normal-gamma and normal-exponential models are compared on two dilution data sets, through testing procedures which represent various experimental designs. Surprisingly, we observe that the implementation of a more accurate parametrisation in the model-based background correction does not increase the sensitivity. These results may be explained by the operating characteristics of the estimators: the normal-gamma background correction offers an improvement in terms of bias, but at the cost of a loss in precision. This paper addresses the lack of fit of the usual normal-exponential model by proposing a more flexible parametrisation of the signal distribution as well as the associated background correction. This new model proves to be considerably more accurate for Illumina microarrays, but the improvement in terms of modeling does not lead to a higher sensitivity in differential analysis. Nevertheless, this realistic modeling makes way for future investigations, in particular to examine the characteristics of pre-processing strategies.

An Intensified Vibratory Milling Process for Enhancing the Breakage Kinetics during the Preparation of Drug Nanosuspensions.

PubMed

Li, Meng; Zhang, Lu; Davé, Rajesh N; Bilgili, Ecevit

2016-04-01

As a drug-sparing approach in early development, vibratory milling has been used for the preparation of nanosuspensions of poorly water-soluble drugs. The aim of this study was to intensify this process through a systematic increase in vibration intensity and bead loading with the optimal bead size for faster production. Griseofulvin, a poorly water-soluble drug, was wet-milled using yttrium-stabilized zirconia beads with sizes ranging from 50 to 1500 μm at low power density (0.87 W/g). Then, this process was intensified with the optimal bead size by sequentially increasing vibration intensity and bead loading. Additional experiments with several bead sizes were performed at high power density (16 W/g), and the results were compared to those from wet stirred media milling. Laser diffraction, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and dissolution tests were used for characterization. Results for the low power density indicated 800 μm as the optimal bead size which led to a median size of 545 nm with more than 10% of the drug particles greater than 1.8 μm albeit the fastest breakage. An increase in either vibration intensity or bead loading resulted in faster breakage. The most intensified process led to 90% of the particles being smaller than 300 nm. At the high power intensity, 400 μm beads were optimal, which enhanced griseofulvin dissolution significantly and signified the importance of bead size in view of the power density. Only the optimally intensified vibratory milling led to a comparable nanosuspension to that prepared by the stirred media milling.

Use of Antibiotic Impregnated Resorbable Beads Reduces Pressure Ulcer Recurrence: A Retrospective Analysis.

PubMed

Khansa, Ibrahim; Barker, Jenny C; Ghatak, Piya Das; Sen, Chandan K; Gordillo, Gayle M

2018-05-17

Recurrence of pressure ulcers remains common. We have employed resorbable antibiotic beads as a therapeutic strategy to deliver high local antibiotic concentrations to the debridement site. Our objective was to determine whether the use of resorbable antibiotic- beads would reduce pressure ulcer recurrence. We reviewed all stage IV pressure ulcers treated with excision, partial ostectomy and flap coverage over 16 years. Baseline patient factors (location of ulcer, presence of osteomyelitis, preoperative prealbumin), surgical factors (type of flap, use of antibiotic beads, bone culture results) and postoperative outcomes (ulcer recurrence at 1 year, dehiscence, seroma, cellulitis) were collected. Outcomes of patients who received antibiotic-impregnated beads were compared to those who did not. 86 patients with 120 stage IV pressure ulcers underwent excision and flap coverage. This included 16 ulcers where antibiotic beads were used, and 104 where they were not. The overall ulcer recurrence rate at 12 months was 35.8%. The recurrence rate in the group treated with antibiotic beads was significantly lower than the group without beads (12.5% vs. 39.4%, p=0.03). Overall, complication rates between the two groups were similar (43.8% vs. 51.9%, p=0.54). No systemic or local toxicity from antibiotic beads occurred. Scanning electron microscopy images of sacral bone from one case showed bacterial biofilm even after debridement. Pressure ulcer recurrence at 1 year after excision and flap coverage decreased significantly with the use of resorbable antibiotic beads. This article is protected by copyright. All rights reserved. © 2018 by the Wound Healing Society.

Development of a novel colorimetric sensor based on alginate beads for monitoring rainbow trout spoilage.

PubMed

Majdinasab, Marjan; Hosseini, Seyed Mohammad Hashem; Sepidname, Marziyeh; Negahdarifar, Manizheh; Li, Peiwu

2018-05-01

Alginate is a non-toxic, renewable, and linear copolymer obtained from the brown algae Laminaria digitata that can be easily shaped into beads. Its good gel forming properties have made it useful for entrapping food and pharmaceutical ingredients. In this study, alginate beads were used in a novel application as a colorimetric sensor in food intelligent packaging. Colorimetric sensor was developed through entrapping red cabbage extract as a pH indicator in alginate beads. The pH indicator beads were used in rainbow trout packaging for monitoring fillets spoilage. Color change of beads during fish storage was measured using the CIELab method. The alginate bead colorimetric sensor is validated by measuring total volatile basic nitrogen (TVB-N) levels and microbial populations in fish samples. Moreover, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were evaluated during storage. Results indicated that increasing the bacterial population during storage and production of proteolytic enzymes resulted in protein degradation, accumulation of volatile amine compounds, increase in the pH and finally color change of alginate beads. The values of TVB-N, pH, PV and TBARS increased with time of storage. The results of TVB-N and microbial growth were in accordance with color change of beads and CIELab data. Therefore, the proposed system enjoys a high sensitivity to pH variations and is capable of monitoring the spoilage of fish or other protein-rich products through its wide range of color changes. The alginate beads containing the red cabbage extract can, thus, be used as a low-cost colorimetric sensor for intelligent packaging applications.

Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal.

PubMed

Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng

2016-08-16

Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields.

Simultaneous detection of Escherichia coli O157:H7 and Salmonella Typhimurium: The use of magnetic beads conjugated with multiple capture antibodies

USDA-ARS?s Scientific Manuscript database

Streptavidin-coated magnetic beads were conjugated with biotinylated capture antibodies to both Escherichia coli O157:H7 and Samonella Typhimurium to form multi-pathogen capture immunomagnetic beads (IMB-M). The efficacy of these beads was investigated and compared to the use of a mixture of IMB ag...

The Beads of Translation: Using Beads to Translate mRNA into a Polypeptide Bracelet

ERIC Educational Resources Information Center

Dunlap, Dacey; Patrick, Patricia

2012-01-01

During this activity, by making beaded bracelets that represent the steps of translation, students simulate the creation of an amino acid chain. They are given an mRNA sequence that they translate into a corresponding polypeptide chain (beads). This activity focuses on the events and sites of translation. The activity provides students with a…

Mesoporous zirconium titanium oxides. Part 2: Synthesis, porosity, and adsorption properties of beads.

PubMed

Sizgek, G Devlet; Sizgek, Erden; Griffith, Christopher S; Luca, Vittorio

2008-11-04

Mesoporous zirconium titanium mixed-oxide beads having disordered wormhole textures and mole fractions of Zr (x) ranging from x=0.25 to 0.67 have been prepared. The bead preparation method combined the forced hydrolysis of mixtures of zirconium-titanium alkoxides in the presence of long-chain carboxylates with external gelation. Uniformly sized beads could be produced in the size range 0.5-1.1 mm by varying the droplet size and viscosity of the mixed-oxide sol, thus making them suitable for large-scale column chromatographic applications. The beads exhibited narrow pore size distributions with similar mean pore diameters of around 3.7 nm. The specific surface areas of the beads were linked to the Zr mole fraction in the precursor solution and were generally greater than 350 m2/g for x=0.5. A combination of scanning transmission electron microscopy and X-ray absorption fine structure analysis indicated that the pore walls of the beads were composed of atomically dispersed Zr and Ti to form a continuous network of Zr-O-Ti bonds. Mass transport in the beads was evaluated by monitoring the kinetics of vanadate and vanadyl adsorption at pH 10.5 and 0.87, respectively.

Wax-incorporated emulsion gel beads of calcium pectinate for intragastric floating drug delivery.

PubMed

Sriamornsak, Pornsak; Asavapichayont, Panida; Nunthanid, Jurairat; Luangtana-Anan, Manee; Limmatvapirat, Sontaya; Piriyaprasarth, Suchada

2008-01-01

The purpose of this study was to prepare wax-incorporated pectin-based emulsion gel beads using a modified emulsion-gelation method. The waxes in pectin-olive oil mixtures containing a model drug, metronidazole, were hot-melted, homogenized and then extruded into calcium chloride solution. The beads formed were separated, washed with distilled water and dried for 12 h. The influence of various types and amounts of wax on floating and drug release behavior of emulsion gel beads of calcium pectinate was investigated. The drug-loaded gel beads were found to float on simulated gastric fluid if the sufficient amount of oil was used. Incorporation of wax into the emulsion gel beads affected the drug release. Water-soluble wax (i.e. polyethylene glycol) increased the drug release while other water-insoluble waxes (i.e. glyceryl monostearate, stearyl alcohol, carnauba wax, spermaceti wax and white wax) significantly retarded the drug release. Different waxes had a slight effect on the drug release. However, the increased amount of incorporated wax in the formulations significantly sustained the drug release while the beads remained floating. The results suggest that wax-incorporated emulsion gel beads could be used as a carrier for intragastric floating drug delivery.

Analysis of surface properties of fixed and live cells using derivatized agarose beads.

PubMed

Navarro, Vanessa M; Walker, Sherri L; Badali, Oliver; Abundis, Maria I; Ngo, Lylla L; Weerasinghe, Gayani; Barajas, Marcela; Zem, Gregory; Oppenheimer, Steven B

2002-01-01

A novel assay has been developed for the histochemical characterization of surface properties of cells based on their adhesion to agarose beads derivatized with more than 100 types of molecules, including sugars, lectins and other proteins, and amino acids. The assay simply involves mixing small quantities of washed cells and beads in droplets on glass microscope slides and determining to which beads various cell types adhere. Distilled water was found to be the best medium for this assay because added ions or molecules in other media inhibit adhesion in some cases. Many cells, however, cannot tolerate distilled water. Here we show that cells fixed with either of two fixatives (1% formaldehyde or Prefer fixative) displayed similar bead-binding properties as did live cells. Specificity of cell-bead binding was tested by including specific free molecules in the test suspensions in hapten-type inhibition experiments. If a hapten compound inhibited live-cell adhesion to a specific bead, it also inhibited fixed-cell adhesion to a specific bead. The results of these experiments suggest that fixed cells display authentic surface properties, opening the door for the use of this assay with many cell types that cannot tolerate distilled water.

Effect of matrix composition and process conditions on casein-gelatin beads floating properties.

PubMed

Bulgarelli, E; Forni, F; Bernabei, M T

2000-04-05

Casein-gelatin beads have been prepared by emulsification extraction method and cross-linked with D,L-glyceraldehyde in an acetone-water mixture 3:1 (v/v). Casein emulsifying properties cause air bubble incorporation and the formation of large holes in the beads. The high porosity of the matrix influences the bead properties such as drug loading, drug release and floatation. These effects have been stressed by comparison with low porous beads, artificially prepared without cavities. The percentage of casein in the matrix increases the drug loading of both low and high porous matrices, although the loading of high porous matrices is lower than that of low porous matrices. As a matter of fact, the drug should be more easily removed during washing and recovery because of the higher superficial pore area of the beads. This can explain the drug release rate increase, observed in high porous matrix, in comparison with beads without cavities. This is due to the rapid diffusion of the drug through water filled pores. The study shows that cavities act as an air reservoir and enable beads to float. Therefore, casein seems to be a material suitable to the inexpensive formation of an air reservoir for floating systems.

Sorption kinetics of zinc and nickel on modified chitosan.

PubMed

Tripathi, Nimisha; Choppala, Girish; Singh, Raj S; Srivastava, Prashant; Seshadri, Balaji

2016-09-01

This study was conducted to evaluate the effect of equilibration time on adsorption of zinc [Zn(II)] and nickel [Ni(II)] on pure and modified chitosan beads. The initial adsorption of Zn(II) was high on molybdenum (Mo)-impregnated chitosan beads (MoCB) during the initial 60 min. However, after 240 min, Zn(II) adsorption occurred more on single super phosphate chitosan beads (SSPCB), followed by monocalcium phosphate chitosan beads (MCPCB), untreated pure chitosan beads (UCB), and MoCB. Similarly, Ni(II) adsorption was greatest on MoCB during the initial 60 min. At the conclusion of the experiment (at 240 min), the greatest adsorption was occurred on MCPCB, followed by MoCB, UCB, and SSPCB. Chemical sorption and intra-particle diffusion were probably the dominant processes responsible for Zn(II) and Ni(II) sorption onto chitosan beads. The results demonstrated that modified chitosan beads were effective in adsorbing Zn and Ni and hence, could be used for the removal of these toxic metals from soil.

Ionic liquid as a potential solvent for preparation of collagen-alginate-hydroxyapatite beads as bone filler.

PubMed

Iqbal, Bushra; Sarfaraz, Zenab; Muhammad, Nawshad; Ahmad, Pervaiz; Iqbal, Jibran; Khan, Zia Ul Haq; Gonfa, Girma; Iqbal, Farasat; Jamal, Arshad; Rahim, Abdur

2018-07-01

In this study, collagen/alginate/hydroxyapatite beads having different proportions were prepared as bone fillers for the restoration of osteological defects. Ionic liquid was used to dissolve the collagen and subsequently the solution was mixed with sodium alginate solution. Hydroxyapatite was added in different proportions, with the rationale to enhance mechanical as well as biological properties. The prepared solutions were given characteristic bead shapes by dropwise addition into calcium chloride solution. The prepared beads were characterized using FTIR, XRD, TGA and SEM analysis. Microhardness testing was used to evaluate the mechanical properties. The prepared beads were investigated for water adsorption behavior to ascertain its ability for body fluid uptake and adjusted accordingly to the bone cavity. Drug loading and subsequently the antibacterial activity was investigated for the prepared beads. The biocompatibility was assessed using the hemolysis testing and cell proliferation assay. The prepared collagen-alginate-HA beads, having biocompatibility and good mechanical properties, have showed an option of promising biologically active bone fillers for bone regeneration.

Energy efficient bead milling of microalgae: Effect of bead size on disintegration and release of proteins and carbohydrates.

PubMed

Postma, P R; Suarez-Garcia, E; Safi, C; Yonathan, K; Olivieri, G; Barbosa, M J; Wijffels, R H; Eppink, M H M

2017-01-01

The disintegration of three industry relevant algae (Chlorella vulgaris, Neochloris oleoabundans and Tetraselmis suecica) was studied in a lab scale bead mill at different bead sizes (0.3-1mm). Cell disintegration, proteins and carbohydrates released into the water phase followed a first order kinetics. The process is selective towards proteins over carbohydrates during early stages of milling. In general, smaller beads led to higher kinetic rates, with a minimum specific energy consumption of ⩽0.47kWhkg DW -1 for 0.3mm beads. After analysis of the stress parameters (stress number and stress intensity), it appears that optimal disintegration and energy usage for all strains occurs in the 0.3-0.4mm range. During the course of bead milling, the native structure of the marker protein Rubisco was retained, confirming the mildness of the disruption process. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Using a laser source to measure the refractive index of glass beads and Debye theory analysis.

PubMed

Li, Shui-Yan; Qin, Shuang; Li, Da-Hai; Wang, Qiong-Hua

2015-11-20

Using a monochromatic laser beam to illuminate a homogeneous glass bead, some rainbows will appear around it. This paper concentrates on the study of the scattering intensity distribution and the method of measuring the refractive index for glass beads based on the Debye theory. It is found that the first rainbow due to the scattering superposition of backward light of the low-refractive-index glass beads can be explained approximately with the diffraction, the external reflection plus the one internal reflection, while the second rainbow of high-refractive-index glass beads is due to the contribution from the diffraction, the external reflection, the direct transmission, and the two internal reflections. The scattering intensity distribution is affected by the refractive index, the radius of the glass bead, and the incident beam width. The effects of the refractive index and the glass bead size on the first and second minimum deviation angle position are analyzed in this paper. The results of the measurements agree very well with the specifications.

Pulsed laser manipulation of an optically trapped bead: averaging thermal noise and measuring the pulsed force amplitude.

PubMed

Lindballe, Thue B; Kristensen, Martin V G; Berg-Sørensen, Kirstine; Keiding, Søren R; Stapelfeldt, Henrik

2013-01-28

An experimental strategy for post-eliminating thermal noise on position measurements of optically trapped particles is presented. Using a nanosecond pulsed laser, synchronized to the detection system, to exert a periodic driving force on an optically trapped 10 μm polystyrene bead, the laser pulse-bead interaction is repeated hundreds of times. Traces with the bead position following the prompt displacement from equilibrium, induced by each laser pulse, are averaged and reveal the underlying deterministic motion of the bead, which is not visible in a single trace due to thermal noise. The motion of the bead is analyzed from the direct time-dependent position measurements and from the power spectrum. The results show that the bead is on average displaced 208 nm from the trap center and exposed to a force amplitude of 71 nanoNewton, more than five orders of magnitude larger than the trapping forces. Our experimental method may have implications for microrheology.

Blends of jackfruit seed starch-pectin in the development of mucoadhesive beads containing metformin HCl.

PubMed

Nayak, Amit Kumar; Pal, Dilipkumar

2013-11-01

In this work, calcium pectinate-jackfruit (Artocarpus heterophyllus Lam.) seed starch (JFSS) mucoadhesive beads containing metformin HCl were developed through ionotropic-gelation. Effects of pectin and JFSS amounts on drug encapsulation efficiency (DEE), and cumulative drug release after 10 h (R10 h) were optimized using 3(2) factorial design. The optimized calcium pectinate-JFSS beads containing metformin HCl showed DEE of 94.11 ± 3.92%, R10 h of 48.88 ± 2.02%, and mean diameter of 2.06 ± 0.20 mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The pH of test mediums was found critical for swelling and mucoadhesion of these beads. The optimized calcium pectinate-JFSS beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier B.V. All rights reserved.

Silver nanoparticle-alginate composite beads for point-of-use drinking water disinfection.

PubMed

Lin, Shihong; Huang, Rixiang; Cheng, Yingwen; Liu, Jie; Lau, Boris L T; Wiesner, Mark R

2013-08-01

Silver nanoparticles (AgNPs)-alginate composite beads were synthesized using three different approaches as filler materials of packed columns for simultaneous filtration-disinfection as an alternative portable water treatment process. The prepared composite beads were packed into a column through which Escherichia coli containing water was filtered to evaluate the disinfection efficacy. Excellent disinfection performance (no detectable viable colony) was achieved with a hydraulic retention time (HRT) as short as 1 min (the shortest tested) with the SGR (Simultaneous-Gelation-Reduction) and AR (Adsorption-Reduction) beads that were prepared using in situ reduction of Ag(+). Comparatively, the SGR beads released significantly less Ag(+)/AgNPs than the AR beads did within the same HRT. From the results of this study it was identified that SGR may be the best choice among all three different synthesis approaches in that the SGR beads can achieve satisfactory bactericidal performance with a relatively low material consumption rate. Copyright © 2012 Elsevier Ltd. All rights reserved.

Polymerase chain reaction system using magnetic beads for analyzing a sample that includes nucleic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nasarabadi, Shanavaz

2011-01-11

A polymerase chain reaction system for analyzing a sample containing nucleic acid includes providing magnetic beads; providing a flow channel having a polymerase chain reaction chamber, a pre polymerase chain reaction magnet position adjacent the polymerase chain reaction chamber, and a post pre polymerase magnet position adjacent the polymerase chain reaction chamber. The nucleic acid is bound to the magnetic beads. The magnetic beads with the nucleic acid flow to the pre polymerase chain reaction magnet position in the flow channel. The magnetic beads and the nucleic acid are washed with ethanol. The nucleic acid in the polymerase chain reactionmore » chamber is amplified. The magnetic beads and the nucleic acid are separated into a waste stream containing the magnetic beads and a post polymerase chain reaction mix containing the nucleic acid. The reaction mix containing the nucleic acid flows to an analysis unit in the channel for analysis.« less

Size of the Dynamic Bead in Polymers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agapov, Alexander L; Sokolov, Alexei P

2010-01-01

Presented analysis of neutron, mechanical, and MD simulation data available in the literature demonstrates that the dynamic bead size (the smallest subchain that still exhibits the Rouse-like dynamics) in most of the polymers is significantly larger than the traditionally defined Kuhn segment. Moreover, our analysis emphasizes that even the static bead size (e.g., chain statistics) disagrees with the Kuhn segment length. We demonstrate that the deficiency of the Kuhn segment definition is based on the assumption of a chain being completely extended inside a single bead. The analysis suggests that representation of a real polymer chain by the bead-and-spring modelmore » with a single parameter C cannot be correct. One needs more parameters to reflect correctly details of the chain structure in the bead-and-spring model.« less

A facile method for the preparation of monodisperse beads with uniform pore sizes for cell culture.

PubMed

Moon, Seung-Kwan; Oh, Myeong-Jin; Paik, Dong-Hyun; Ryu, Tae-Kyung; Park, Kyeongsoon; Kim, Sung-Eun; Park, Jong-Hoon; Kim, Jung-Hyun; Choi, Sung-Wook

2013-03-12

This paper describes a facile method for the preparation of porous gelatin beads with uniform pore sizes using a simple fluidic device and their application as supporting materials for cell culture. An aqueous gelatin droplet containing many uniform toluene droplets, produced in the fluidic device, is dropped into liquid nitrogen for instant freezing and the small toluene droplets evolve into pores in the gelatin beads after removal of toluene and then freeze-drying. The porous gelatin beads exhibit a uniform pore size and monodisperse diameter as well as large open pores at the surface. Fluorescence microscopy images of fibroblast-loaded gelatin beads confirm the attachment and proliferation of the cells throughout the porous gelatin beads. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Montmorillonite-Alginate Composites as a Drug delivery System: Intercalation and In vitro Release of Diclofenac sodium

PubMed Central

Kevadiya, B. D.; Patel, H. A.; Joshi, G. V.; Abdi, S. H. R.; Bajaj, H. C.

2010-01-01

Diclofenac sodium and alginate was intercalated into montmorillonite to form uniform sized beads by gelation method. The structure and surface morphology of the synthesized composite beads were characterized by powdered X-ray diffraction, Fourier transform infrared spectroscopy, thermo gravimetric analysis and scanning electron microscopy. Diclofenac release kinetics of the composite in simulated intestinal fluid medium (pH 7.4) and effect of montmorillonite content on the in vitro release of diclofenac from diclofenac-montmorillonite-alginate composites bead was investigated by UV/Vis spectrophotometer. Diclofenac encapsulation efficiency in the montmorillonite-alginate composites bead increases with an increase in the montmorillonite content. The control release of diclofenac from diclofenac-montmorillonite-alginate composites beads was observed to be better as compared to diclofenac-alginate beads. PMID:21969745

The Use of Index-Matched Beads in Optical Particle Counters

PubMed Central

Hu, Zhishang; Ripple, Dean C

2014-01-01

In this paper, we demonstrate the use of 2-pyridinemethanol (2P) aqueous solutions as a refractive index matching liquid. The high refractive index and low viscosity of 2P-water mixtures enables refractive index matching of beads that cannot be index matched with glycerol-water or sucrose-water solutions, such as silica beads that have the refractive index of bulk fused silica or of polymethylmethacrylate beads. Suspensions of beads in a nearly index-matching liquid are a useful tool to understand the response of particle counting instruments to particles of low optical contrast, such as aggregated protein particles. Data from flow imaging and light obscuration instruments are presented for bead diameters ranging from 6 µm to 69 µm, in a matrix liquid spanning the point of matched refractive index. PMID:26601049

Micro-Raman spectroscopy and μ-XRF in the investigation of ancient glass beads from the archaeological sites, eastern Taiwan

NASA Astrophysics Data System (ADS)

San Liou, Ying; Liu, Yi Chang

2017-04-01

Ancient glass beads with different colors, shapes, and stylistics unearthed from the archaeological sites of eastern Taiwan, dating back to approximately 1850-310 BP, have been investigated. It is generally known that glass bead is alien to invade into Taiwan along with metal ware, glass, agate, etc. since the Metal Age of Taiwan. Nevertheless, souring provenance and trade routes still remain controversial. Micro-Raman spectroscopy and μ-XRF have been applied on fifty-six ancient glass beads to reveal the mineralogical and chemical compositions and to help decipher the raw materials used and souring provenance. Micro-Raman measurements indicate the presence of hematite, zincite, siderite, sphalerite, lead tin yellow type II, quartz, feldspar, anatase, rutite, ankerite, graphite, calcite, etc. Among them, hematite, zincite, siderite, sphalerite, lead tin yellow type II, and rutile were found to be colorants/opacifiers. Moreover, crystalline phases such as lead tin yellow type II (PbSn1-xSixO3), zincite (ZnO), tricalcium diphosphate (Ca2(PO4)2), sphalerite ((Zn, Fe)S) and ankerite (Ca(Fe, Mg, Mn)(CO3)2) were detected in ancient glass beads unearthed from Taiwan for the first time. The chemical results obtained by μXRF show SiO2, Al2O3, Na2O, K2O, MgO, CaO, and PbO as the most abundant oxides. Na2O, K2O, Al2O3, MgO, and PbO could be the main/minor fluxes and colorants. In general, results of mineralogical and chemical analyses are compatible. According to chemical results, ancient glass beads can be classified as mineral soda alumina glass (m-Na-Al glass), soda plant ash glass (v-Na-Ca glass), lead silicate glass, and some less well known types. Mineral soda alumina and soda plant ash glass beads, as well as lead silicate glass beads are generally believed to be the distinct phases of production and exchange in Southeast Asia and China, respectively. In terms of chronology of glass bead, beads excavated from sites of 1850-930 BP are mineral soda alumina glass (m-Na-Al glass) and soda plant ash glass (v-Na-Ca glass). On the other hand, beads from sites of <930 BP are belonging to lead silicate glass. It is indicated that the souring provenance of ancient beads of eastern Taiwan is probably a multiple sources, i.e., in earlier time, glass beads were brought into Taiwan through the maritime exchange and/or trade activities between Taiwan and Southeast Asia; at the later period, lead silicate glass beads were imported from China. However, some mineral soda alumina and soda plant ash glass beads were found in a later period, it might be attributed to glass beads reuse or trade route between Taiwan and Southeast Asia is successive since ca. 1850 BP.

Jeffamine Derivatized TentaGel Beads and PDMS Microbead Cassettes for Ultra-high Throughput in situ Releasable Solution-Phase Cell-based Screening of OBOC Combinatorial Small Molecule Libraries

PubMed Central

Townsend, Jared B.; Shaheen, Farzana; Liu, Ruiwu; Lam, Kit S.

2011-01-01

A method to efficiently immobilize and partition large quantities of microbeads in an array format in microfabricated polydimethylsiloxane (PDMS) cassette for high-throughput in situ releasable solution-phase cell-based screening of one-bead-one-compound (OBOC) combinatorial libraries is described. Commercially available Jeffamine triamine T-403 (∼440 Da) was derivatized such that two of its amino groups were protected by Fmoc and the remaining amino group capped with succinic anhydride to generate a carboxyl group. This resulting tri-functional hydrophilic polymer was then sequentially coupled two times to the outer layer of topologically segregated bilayer TentaGel (TG) beads with solid phase peptide synthesis chemistry, resulting in beads with increased loading capacity, hydrophilicity and porosity at the outer layer. We have found that such bead configuration can facilitate ultra high-throughput in situ releasable solution-phase screening of OBOC libraries. An encoded releasable OBOC small molecule library was constructed on Jeffamine derivatized TG beads with library compounds tethered to the outer layer via a disulfide linker and coding tags in the interior of the beads. Compound-beads could be efficiently loaded (5-10 minutes) into a 5 cm diameter Petri dish containing a 10,000-well PDMS microbead cassette, such that over 90% of the microwells were each filled with only one compound-bead. Jurkat T-lymphoid cancer cells suspended in Matrigel® were then layered over the microbead cassette to immobilize the compound-beads. After 24 hours of incubation at 37°C, dithiothreitol was added to trigger the release of library compounds. Forty-eight hours later, MTT reporter assay was used to identify regions of reduced cell viability surrounding each positive bead. From a total of about 20,000 beads screened, 3 positive beads were detected and physically isolated for decoding. A strong consensus motif was identified for these three positive compounds. These compounds were re-synthesized and found to be cytotoxic (IC50 50-150 μM) against two T-lymphoma cell lines and less so against the MDA-MB 231 breast cancer cell line. This novel ultra high-throughput OBOC releasable method can potentially be adapted to many existing 96- or 384-well solution-phase cell-based or biochemical assays. PMID:20593859

Chloride Cotransporters as a Molecular Mechanism underlying Spreading Depolarization-Induced Dendritic Beading.

PubMed

Steffensen, Annette B; Sword, Jeremy; Croom, Deborah; Kirov, Sergei A; MacAulay, Nanna

2015-09-02

Spreading depolarizations (SDs) are waves of sustained neuronal and glial depolarization that propagate massive disruptions of ion gradients through the brain. SD is associated with migraine aura and recently recognized as a novel mechanism of injury in stroke and brain trauma patients. SD leads to neuronal swelling as assessed in real time with two-photon laser scanning microscopy (2PLSM). Pyramidal neurons do not express aquaporins and thus display low inherent water permeability, yet SD rapidly induces focal swelling (beading) along the dendritic shaft by unidentified molecular mechanisms. To address this issue, we induced SD in murine hippocampal slices by focal KCl microinjection and visualized the ensuing beading of dendrites expressing EGFP by 2PLSM. We confirmed that dendritic beading failed to arise during large (100 mOsm) hyposmotic challenges, underscoring that neuronal swelling does not occur as a simple osmotic event. SD-induced dendritic beading was not prevented by pharmacological interference with the cytoskeleton, supporting the notion that dendritic beading may result entirely from excessive water influx. Dendritic beading was strictly dependent on the presence of Cl(-), and, accordingly, combined blockade of Cl(-)-coupled transporters led to a significant reduction in dendritic beading without interfering with SD. Furthermore, our in vivo data showed a strong inhibition of dendritic beading during pharmacological blockage of these cotransporters. We propose that SD-induced dendritic beading takes place as a consequence of the altered driving forces and thus activity for these cotransporters, which by transport of water during their translocation mechanism may generate dendritic beading independently of osmotic forces. Spreading depolarization occurs during pathological conditions such as stroke, brain injury, and migraine and is characterized as a wave of massive ion translocation between intracellular and extracellular space in association with recurrent transient focal swelling (beading) of dendrites. Numerous ion channels have been demonstrated to be involved in generation and propagation of spreading depolarization, but the molecular machinery responsible for the dendritic beading has remained elusive. Using real-time in vitro and in vivo two-photon laser scanning microscopy, we have identified the transport mechanisms involved in the detrimental focal swelling of dendrites. These findings have clear clinical significance because they may point to a new class of pharmacological targets for prevention of neuronal swelling that consequently will serve as neuroprotective agents. Copyright © 2015 the authors 0270-6474/15/3512172-16$15.00/0.

Comparison of Chlamydia trachomatis serovar L2 growth in polarized genital epithelial cells grown in three-dimensional culture with non-polarized cells.

PubMed

Dessus-Babus, Sophie; Moore, Cheryl G; Whittimore, Judy D; Wyrick, Priscilla B

2008-04-01

A common model for studying Chlamydia trachomatis and growing chlamydial stocks uses Lymphogranuloma venereum serovar L2 and non-polarized HeLa cells. However, recent publications indicate that the growth rate and progeny yields can vary considerably for a particular strain depending on the cell line/type used, and seem to be partially related to cell tropism. In the present study, the growth of invasive serovar L2 was compared in endometrial HEC-1B and endocervical HeLa cells polarized on collagen-coated microcarrier beads, as well as in HeLa cells grown in tissue culture flasks. Microscopy analysis revealed no difference in chlamydial attachment/entry patterns or in inclusion development throughout the developmental cycle between cell lines. Very comparable growth curves in both cell lines were also found using real-time PCR analysis, with increases in chlamydial DNA content of 400-500-fold between 2 and 36 h post-inoculation. Similar progeny yields with comparable infectivity were recovered from HEC-1B and HeLa cell bead cultures, and no difference in chlamydial growth was found in polarized vs. non-polarized HeLa cells. In conclusion, unlike other C. trachomatis strains such as urogenital serovar E, invasive serovar L2 grows equally well in physiologically different endometrial and endocervical environments, regardless of the host cell polarization state.

Retro-reflection of glass beads for traffic road stripe paints

NASA Astrophysics Data System (ADS)

Grosges, T.

2008-06-01

The retro-reflection of light by glass beads injected in road stripes is studied experimentally and theoretically. The complete contribution of the retro-reflected intensity is modelled by taking into account the glass beads and the paint stripes. The efficiency of such a technique is evaluated for various compositions and densities of glass beads injected in paints, including the paint meniscus contributions.

The role of silica colloids on facilitated cesium transport through glass bead columns and modeling

NASA Astrophysics Data System (ADS)

Noell, Alan L.; Thompson, Joseph L.; Corapcioglu, M. Yavuz; Triay, Inés R.

1998-05-01

Groundwater colloids can act as a vector which enhances the migration of contaminants. While sorbed to mobile colloids, contaminants can be held in the aqueous phase which prevents them from interacting with immobile aquifer surfaces. In this study, an idealized laboratory set-up was used to examine the influence of amorphous silica colloids on the transport of cesium. Synthetic groundwater and saturated glass bead columns were used to minimize the presence of natural colloidal material. The columns were assembled in replicate, some packed with 150-210 μm glass bead and others packed with 355-420 μm glass beads. The colloids used in these experiments were 100 nm amorphous silica colloids from Nissan Chemical Company. In the absence of these colloids, the retardation factor for cesium was 8.0 in the 150-210 μm glass bead columns and 3.6 in the 355-420 μm glass bead columns. The influence of anthropogenic colloids was tested by injecting 0.09 pore volume slugs of an equilibrated suspension of cesium and colloids into the colloid-free columns. Although there was little noticeable facilitation in the smaller glass bead columns, there was a slight reduction in the retardation of cesium in the larger glass bead columns. This was attributed to cesium having less of a retention time in the larger glass bead columns. When cesium was injected into columns with a constant flux of colloids, the retardation of cesium was reduced by 14-32% in the 150-210 μm glass bead columns and by 38-51% in the 355-420 μm glass bead columns. A model based on Corapcioglu and Jiang (1993) [Corapcioglu, M.Y., Jiang, S., 1993. Colloid-facilitated groundwater contaminant transport, Water Resour. Res., 29 (7) 2215-2226] was compared with the experimental elution data. When equilibrium sorption expressions were used and the flux of colloids through the glass bead columns was constant, the colloid facilitated transport of cesium was able to be described using an effective retardation coefficient. Fully kinetic simulations, however, more accurately described the colloid facilitated transport of cesium.

Arsenic and fluoride removal from contaminated drinking water with Haix-Fe-Zr and Haix-Zr resin beads.

PubMed

Phillips, Debra H; Sen Gupta, Bhaskar; Mukhopadhyay, Soumyadeep; Sen Gupta, Arup K

2018-06-01

The objective of the study was to carry-out batch tests to examine the effectiveness of Haix-Fe-Zr and Haix-Zr resin beads in the removal of As(III), As(V) and F - from groundwater with a similar geochemistry to a site where a community-based drinking water plant has been installed in West Bengal, India. The groundwater was spiked separately with ∼200 μg/L As(III) and As(V) and 5 mg/L F - . Haix-Zr resin beads were more effective than Haix-Fe-Zr resin beads in removing As(III) and As(V). Haix-Zr resin beads showed higher removal of As(V) compared to As(III). Haix-Zr resin beads removed As(V) below the WHO (10 μg/L) drinking water standards at 8.79 μg/L after 4 h of shaking, while As(III) was reduced to 7.72 μg/L after 8 h of shaking. Haix-Fe-Zr resin beads were more effective in removing F - from the spiked groundwater compared to Haix-Zr resin beads. Concentrations of F - decreased from 6.27 mg/L to 1.26 mg/L, which is below the WHO drinking water standards (1.5 mg/L) for F - , after 15 min of shaking with Haix-Fe-Zr resin beads. After 20 min of shaking in groundwater treated with Haix-Zr resin beads, F - concentrations decreased from 6.27 mg/L to 1.43 mg/L. In the removal of As(III), As(V), and F - from the groundwater, Haix-Fe-Zr and Haix-Zr resin beads fit the parabolic diffusion equation (PDE) suggesting that adsorption of these contaminants was consistent with inter-particle diffusion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bacterial polyester inclusions engineered to display vaccine candidate antigens for use as a novel class of safe and efficient vaccine delivery agents.

PubMed

Parlane, Natalie A; Wedlock, D Neil; Buddle, Bryce M; Rehm, Bernd H A

2009-12-01

Bioengineered bacterial polyester inclusions have the potential to be used as a vaccine delivery system. The biopolyester beads were engineered to display a fusion protein of the polyester synthase PhaC and the two key antigens involved in immune response to the infectious agent that causes tuberculosis, Mycobacterium tuberculosis, notably antigen 85A (Ag85A) and the 6-kDa early secreted antigenic target (ESAT-6) from Mycobacterium tuberculosis. Polyester beads displaying the respective fusion protein at a high density were successfully produced (henceforth called Ag85A-ESAT-6 beads) by recombinant Escherichia coli. The ability of the Ag85A-ESAT-6 beads to enhance mouse immunity to the displayed antigens was investigated. The beads were not toxic to the animals, as determined by weight gain and absence of lesions at the inoculation site in immunized animals. In vivo injection of the Ag85A-ESAT-6 beads in mice induced significant humoral and cell-mediated immune responses to both Ag85A and ESAT-6. Vaccination with Ag85A-ESAT-6 beads was efficient at stimulating immunity on their own, and this ability was enhanced by administration of the beads in an oil-in-water emulsion. In addition, vaccination with the Ag85A-ESAT-6 beads induced significantly stronger humoral and cell-mediated immune responses than vaccination with an equivalent dose of the fusion protein Ag85A-ESAT-6 alone. The immune response induced by the beads was of a mixed Th1/Th2 nature, as assessed from the induction of the cytokine gamma interferon (Th1 immune response) and increased levels of immunoglobulin G1 (Th2 immune response). Hence, engineered biopolyester beads displaying foreign antigens represent a new class of versatile, safe, and biocompatible vaccines.

Three-dimensional Printing in Developing Countries

PubMed Central

Ibrahim, Ahmed M. S.; Jose, Rod R.; Rabie, Amr N.; Gerstle, Theodore L.; Lee, Bernard T.

2015-01-01

Summary: The advent of 3-dimensional (3D) printing technology has facilitated the creation of customized objects. The lack of regulation in developing countries renders conventional means of addressing various healthcare issues challenging. 3D printing may provide a venue for addressing many of these concerns in an inexpensive and easily accessible fashion. These may potentially include the production of basic medical supplies, vaccination beads, laboratory equipment, and prosthetic limbs. As this technology continues to improve and prices are reduced, 3D printing has the potential ability to promote initiatives across the entire developing world, resulting in improved surgical care and providing a higher quality of healthcare to its residents. PMID:26301132

Three-dimensional Printing in Developing Countries.

PubMed

Ibrahim, Ahmed M S; Jose, Rod R; Rabie, Amr N; Gerstle, Theodore L; Lee, Bernard T; Lin, Samuel J

2015-07-01

The advent of 3-dimensional (3D) printing technology has facilitated the creation of customized objects. The lack of regulation in developing countries renders conventional means of addressing various healthcare issues challenging. 3D printing may provide a venue for addressing many of these concerns in an inexpensive and easily accessible fashion. These may potentially include the production of basic medical supplies, vaccination beads, laboratory equipment, and prosthetic limbs. As this technology continues to improve and prices are reduced, 3D printing has the potential ability to promote initiatives across the entire developing world, resulting in improved surgical care and providing a higher quality of healthcare to its residents.

Silver Foam Technologies Healing Research Program

DTIC Science & Technology

2009-09-01

colonization and growth. Because many of these wounds cannot be closed primarily, the surgeon is left with packing the wound open using standard gauze...to standard gauze bandages in clinical use . Two inches in width and length and one quarter inch thick, four inches in width and length and one...incorporation into the foam. Of the agents that were identified and selected only two Zeolite and Silver Glass Beads agents were capable of being

Controlled release of D-glucose from starch granules containing 29% free D-glucose and Eudragit L100-55 as a binding and coating agent.

PubMed

Kim, Yeon-Kye; Mukerjea, Rupendra; Robyt, John F

2010-05-27

Waxy maize starch (100% amylopectin) granules were modified by reaction of the granules with glucoamylase in a minimum amount of water to give 29% (w/w) D-glucose inside the granules [Kim, Y.-K.; Robyt, J. F. Carbohydr. Res.1999, 318, 129-134]. These granules were made into beads by dropping an ethanol slurry of starch and different amounts of Eudragit L100-55 in a constant ratio of 100:1 from a pipette onto Whatman 3MM filter paper. The starch beads were air dried and then repeatedly sprayed 0-12 times with 2.0% (w/v) Eudragit L100-55 in ethanol, with drying between each spraying, to coat the surface of the starch beads, giving different amounts of Eudragit L100-55 coating. Seven different kinds of beads, with different amounts of Eudragit L100-55 binding and coating agent, were obtained. The rates of release of D-glucose into water from the seven kinds of beads were inversely proportional to the amount of binding and coating agent. Bead type I, which was without any binding and coating gave a fast 100% release of D-glucose in 30 min. Beads II and III also gave a fast 100% release in 60 min and 90 min, respectively. Bead IV gave a near linear release of 97% D-glucose in 150 min; Bead V gave a 50% release in 120 min followed by the remaining 50% in 60 min; and Beads VI and VII gave a slow release of 10% and 4%, respectively, from 0 to 120 min, followed by a rapid 100% release from 120 to 180 min. (c) 2010 Elsevier Ltd. All rights reserved.

A novel alginate-encapsulated system to study biological response to critical-sized wear particles of UHMWPE loaded with alendronate sodium.

PubMed

Liu, Yumei; Shi, Feng; Bo, Lin; Zhi, Wei; Weng, Jie; Qu, Shuxin

2017-10-01

The aim of this study was to develop a novel alginate-encapsulated system (Alg beads) to investigate the cell response to critical-sized wear particles of ultra-high molecular weight polyethylene loaded with alendronate sodium (UHMWPE-ALN), one of the most effective drugs to treat bone resorption in clinic. The extrusion method was used to prepare Alg beads encapsulating rat calvarial osteoblasts (RCOs) and critical-sized UHMWPE-ALN wear particles with spherical morphology and uniform size. The morphology, permeability and stability of Alg beads were characterized. The proliferation, ALP activity, cell apoptosis and distribution of live/dead RCOs co-cultured with wear particles in Alg beads were evaluated. RCOs and critical-sized UHMWPE-ALN wear particles distributed evenly and contacted efficiently in Alg beads. Alg beads were both permeable to trypsin and BSA, while the smaller the molecular was, the larger the diffuse was. The proliferation of RCOs in Alg beads increased with time, which indicated that Alg beads provided suitable conditions for cell culture. The long-term stability of Alg beads indicated the possibility for the longer time of co-cultured cells with wear particles. Critical-sized UHMWPE-ALN and UHMWPE wear particles both inhibited the proliferation and differentiation of RCOs, and induced the apoptosis of RCOs encapsulated in Alg beads. However, these effects could be significantly alleviated by the ALN released from the critical-sized UHMWPE-ALN wear particles. The present results suggested that this novel-developed co-culture system was feasible to evaluate the cell response to critical-sized UHMWPE-ALN wear particles for a longer time. Copyright © 2017 Elsevier B.V. All rights reserved.

Operational parameters and their influence on particle-side mass transfer resistance in a packed bed bioreactor.

PubMed

Hussain, Amir; Kangwa, Martin; Yumnam, Nivedita; Fernandez-Lahore, Marcelo

2015-12-01

The influence of internal mass transfer on productivity as well as the performance of packed bed bioreactor was determined by varying a number of parameters; chitosan coating, flow rate, glucose concentration and particle size. Saccharomyces cerevisiae cells were immobilized in chitosan and non-chitosan coated alginate beads to demonstrate the effect on particle side mass transfer on substrate consumption time, lag phase and ethanol production. The results indicate that chitosan coating, beads size, glucose concentration and flow rate have a significant effect on lag phase duration. The duration of lag phase for different size of beads (0.8, 2 and 4 mm) decreases by increasing flow rate and by decreasing the size of beads. Moreover, longer lag phase were found at higher glucose medium concentration and also with chitosan coated beads. It was observed that by increasing flow rates; lag phase and glucose consumption time decreased. The reason is due to the reduction of external (fluid side) mass transfer as a result of increase in flow rate as glucose is easily transported to the surface of the beads. Varying the size of beads is an additional factor: as it reduces the internal (particle side) mass transfer by reducing the size of beads. The reason behind this is the distance for reactants to reach active site of catalyst (cells) and the thickness of fluid created layer around alginate beads is reduced. The optimum combination of parameters consisting of smaller beads size (0.8 mm), higher flow rate of 90 ml/min and glucose concentration of 10 g/l were found to be the maximum condition for ethanol production.

Flow-orthogonal bead oscillation in a microfluidic chip with a magnetic anisotropic flux-guide array.

PubMed

van Pelt, Stijn; Derks, Roy; Matteucci, Marco; Hansen, Mikkel Fougt; Dietzel, Andreas

2011-04-01

A new concept for the manipulation of superparamagnetic beads inside a microfluidic chip is presented in this paper. The concept allows for bead actuation orthogonal to the flow direction inside a microchannel. Basic manipulation functionalities were studied by means of finite element simulations and results were oval-shaped steady state oscillations with bead velocities up to 500 μm/s. The width of the trajectory could be controlled by prescribing external field rotation. Successful verification experiments were performed on a prototype chip fabricated with excimer laser ablation in polycarbonate and electroforming of nickel flux-guides. Bead velocities up to 450 μm/s were measured in a 75 μm wide channel. By prescribing the currents in the external quadrupole magnet, the shape of the bead trajectory could be controlled.

Oxytetracycline removal from water by novel microbial embedding gel beads

NASA Astrophysics Data System (ADS)

Wu, Nan; Pan, Peng; Zeng, Ming; Wang, Wei; Xu, Chenshan; Zhang, Zongpeng; Liu, Xinyuan; Wang, Yichao

2018-01-01

As a common antibiotic in aquatic environment, excessive oxytetracycline (OTC) is urgent to be removed due to its great biological toxicity. Compared with the traditional activated sludge, microbial embedding can enhance the treating efficiency. In this study, novel microbial embedding gel beads were produced with the additional agent of cyclodextrin (CD). Results show that CD could increase the mass transfer of OTC into gel beads, possibly because of its strong affinity for organic matters. In terms of OTC biodegradation, gel beads with CD were comparable to gel beads without CD, while the former’s sucrose removal efficiency was higher than the latter. The biodegradation of OTC only occurred in the presence of sucrose. The respiration test also confirmed these findings. Overall, the produced novel gel beads modified with CD could improve the removal performance of OTC.

Functional analysis of alpha5beta1 integrin and lipid rafts in invasion of epithelial cells by Porphyromonas gingivalis using fluorescent beads coated with bacterial membrane vesicles.

PubMed

Tsuda, Kayoko; Furuta, Nobumichi; Inaba, Hiroaki; Kawai, Shinji; Hanada, Kentaro; Yoshimori, Tamotsu; Amano, Atsuo

2008-01-01

Porphyromonas gingivalis, a periodontal pathogen, was previously suggested to exploit alpha5beta1 integrin and lipid rafts to invade host cells. However, it is unknown if the functional roles of these host components are distinct from one another during bacterial invasion. In the present study, we analyzed the mechanisms underlying P. gingivalis invasion, using fluorescent beads coated with bacterial membrane vesicles (MV beads). Cholesterol depletion reagents including methyl-beta-cyclodextrin (MbetaCD) drastically inhibited the entry of MV beads into epithelial cells, while they were less effective on bead adhesion to the cells. Bead entry was also abolished in CHO cells deficient in sphingolipids, components of lipid rafts, whereas adhesion was negligibly influenced. Following MbetaCD treatment, downstream events leading to actin polymerization were abolished; however, alpha5beta1 integrin was recruited to beads attached to the cell surface. Dominant-negative Rho GTPase Rac1 abolished cellular engulfment of the beads, whereas dominant-negative Cdc42 did not. Following cellular interaction with the beads, Rac1 was found to be translocated to the lipid rafts fraction, which was inhibited by MbetaCD. These results suggest that alpha5beta1 integrin, independent of lipid rafts, promotes P. gingivalis adhesion to epithelial cells, while the subsequent uptake process requires lipid raft components for actin organization, with Rho GTPase Rac1.

Osteogenic differentiation of human mesenchymal stem cells in mineralized alginate matrices.

PubMed

Westhrin, Marita; Xie, Minli; Olderøy, Magnus Ø; Sikorski, Pawel; Strand, Berit L; Standal, Therese

2015-01-01

Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days) as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP) than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST) and dental matrix protein-1 (DMP1), markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering.

In vitro evaluation of antibiotic diffusion from antibiotic-impregnated biodegradable beads and polymethylmethacrylate beads.

PubMed Central

Mader, J T; Calhoun, J; Cobos, J

1997-01-01

Antibiotic-impregnated beads are used in the dead bone space following debridement surgery to deliver local, high concentrations of antibiotics. Polymethylmethacrylate (PMMA), 2,000-molecular-weight (MW) polylactic acid (PLA), Poly(DL-lactide)-coglycolide (PL:CG; 90:10, 80:20, and 70:30), and the combination 2,000-MW PLA-70:20 PL:CG were individually mixed with clindamycin, tobramycin, or vancomycin. Beads were placed in 1 ml of phosphate-buffered saline (PBS) and incubated at 37 degrees C. The PBS was changed daily, and the removed PBS samples were stored at -70 degrees C until the antibiotic in each sample was determined by microbiological disk diffusion assay. Nondissolving PMMA beads with tobramycin and clindamycin had concentrations well above breakpoint sensitivity concentrations (i.e., the antibiotic concentrations at the transition point between bacterial killing and resistance to the antibiotic) for more than 90 days, but vancomycin concentrations dropped by day 12. ALl PLA, PL:CG, and the 2,000-MW PLA-70:30 PL:CG biodegradable beads release high concentrations of all the antibiotics in vitro for the period of time needed to treat bone infections (i.e., 4 to 8 weeks). Antibiotic-loaded PLA and PL:CG beads have the advantage of better antibiotic elution and the ability to biodegradable (thereby averting the need for secondary surgery for bead removal) compared to the PMMA beads presently used in the clinical setting. PMID:9021200

Digital analysis of the expression levels of multiple colorectal cancer-related genes by multiplexed digital-PCR coupled with hydrogel bead-array.

PubMed

Qi, Zongtai; Ma, Yinjiao; Deng, Lili; Wu, Haiping; Zhou, Guohua; Kajiyama, Tomoharu; Kambara, Hideki

2011-06-07

To digitally analyze expression levels of multiple genes in one reaction, we proposed a method termed as 'MDHB' (Multiplexed Digital-PCR coupled with Hydrogel Bead-array). The template for bead-based emulsion PCR (emPCR) was prepared by reverse transcription using sequence-tagged primers. The beads recovered from emPCR were immobilized with hydrogel to form a single-bead layer on a chip, and then decoded by gene-specific probe hybridization and Cy3-dUTP based primer extension reaction. The specificity of probe hybridization was improved by using electrophoresis to remove mismatched probes on the bead's surface. The number of positive beads reflects the abundance of expressed genes; the expression levels of target genes were normalized to a housekeeping gene and expressed as the number ratio of green beads to red beads. The discrimination limit of MDHB is 0.1% (i.e., one target molecule from 1000 background molecules), and the sensitivity of the method is below 100 cells when using the β-actin gene as the detection target. We have successfully employed MDHB to detect the relative expression levels of four colorectal cancer (CRC)-related genes (c-myc, COX-2, MMP7, and DPEP1) in 8 tissue samples and 9 stool samples from CRC patients, giving the detection rates of 100% and 77%, respectively. The results suggest that MDHB could be a potential tool for early non-invasive diagnosis of CRC.

Digital detection of multiple minority mutants and expression levels of multiple colorectal cancer-related genes using digital-PCR coupled with bead-array.

PubMed

Huang, Huan; Li, Shuo; Sun, Lizhou; Zhou, Guohua

2015-01-01

To simultaneously analyze mutations and expression levels of multiple genes on one detection platform, we proposed a method termed "multiplex ligation-dependent probe amplification-digital amplification coupled with hydrogel bead-array" (MLPA-DABA) and applied it to diagnose colorectal cancer (CRC). CRC cells and tissues were sampled to extract nucleic acid, perform MLPA with sequence-tagged probes, perform digital emulsion polymerase chain reaction (PCR), and produce a hydrogel bead-array to immobilize beads and form a single bead layer on the array. After hybridization with fluorescent probes, the number of colored beads, which reflects the abundance of expressed genes and the mutation rate, was counted for diagnosis. Only red or green beads occurred on the chips in the mixed samples, indicating the success of single-molecule PCR. When a one-source sample was analyzed using mixed MLPA probes, beads of only one color occurred, suggesting the high specificity of the method in analyzing CRC mutation and gene expression. In gene expression analysis of a CRC tissue from one CRC patient, the mutant percentage was 3.1%, and the expression levels of CRC-related genes were much higher than those of normal tissue. The highly sensitive MLPA-DABA succeeds in the relative quantification of mutations and gene expressions of exfoliated cells in stool samples of CRC patients on the same chip platform. MLPA-DABA coupled with hydrogel bead-array is a promising method in the non-invasive diagnosis of CRC.

Osteogenic Differentiation of Human Mesenchymal Stem Cells in Mineralized Alginate Matrices

PubMed Central

Westhrin, Marita; Xie, Minli; Olderøy, Magnus Ø.; Sikorski, Pawel

2015-01-01

Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days) as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP) than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST) and dental matrix protein-1 (DMP1), markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering. PMID:25769043

Chitosan Enriched Three-Dimensional Matrix Reduces Inflammatory and Catabolic Mediators Production by Human Chondrocytes

PubMed Central

Oprenyeszk, Frederic; Sanchez, Christelle; Dubuc, Jean-Emile; Maquet, Véronique; Henrist, Catherine; Compère, Philippe; Henrotin, Yves

2015-01-01

This in vitro study investigated the metabolism of human osteoarthritic (OA) chondrocytes encapsulated in a spherical matrix enriched of chitosan. Human OA chondrocytes were encapsulated and cultured for 28 days either in chitosan-alginate beads or in alginate beads. The beads were formed by slowly passing dropwise either the chitosan 0.6%–alginate 1.2% or the alginate 1.2% solution through a syringe into a 102 mM CaCl2 solution. Beads were analyzed histologically after 28 days. Interleukin (IL)-6 and -8, prostaglandin (PG) E2, matrix metalloproteinases (MMPs), hyaluronan and aggrecan were quantified directly in the culture supernatant by specific ELISA and nitric oxide (NO) by using a colorimetric method based on the Griess reaction. Hematoxylin and eosin staining showed that chitosan was homogeneously distributed through the matrix and was in direct contact with chondrocytes. The production of IL-6, IL-8 and MMP-3 by chondrocytes significantly decreased in chitosan-alginate beads compared to alginate beads. PGE2 and NO decreased also significantly but only during the first three days of culture. Hyaluronan and aggrecan production tended to increase in chitosan-alginate beads after 28 days of culture. Chitosan-alginate beads reduced the production of inflammatory and catabolic mediators by OA chondrocytes and tended to stimulate the synthesis of cartilage matrix components. These particular effects indicate that chitosan-alginate beads are an interesting scaffold for chondrocytes encapsulation before transplantation to repair cartilage defects. PMID:26020773

Optical diamagnetic biosensor for immunocomplexes on beads

NASA Astrophysics Data System (ADS)

Norina, Svetlana B.

2000-12-01

In the present work, diamagnetic separation parameters for the porous beads are studied using optical video recording microscopy. The possible direct amount determination of single or double macromolecular layers immobilized in the meshes of the porous beads is demonstrated for the concentrations' range used in heterogenic immunotest and the affinity chromatography, where the direct rapid detection of ligands within sorbent particles is known to be the actual task. A gradient diamagnetic biosensor is described as suitable for rapid quantitative detection of single or double macromolecular layers in porous nonmagnetic beads. Measurements of capture traveling time or accumulation radius in gradient magnetic field have shown that it is possible to determine 0.20 mg/ml of macromolecular amount within several seconds. The portative devices were made on the base of the fabre optic technique to detect accumulation radius of collected beads in two gradient magnetic positions: diamagnetic and paramagnetic zones of magnetized wire with 55 μm in diameter and to registrate with a lot of fabre wires having 30 μm in diameters. The successive procedures of the present method can be described by: the obtaining of agarose immuno-beads, the incubation of beads with the ligand sample or the injection of sample through affinity mini-column, the submerging of the loaded beads into the glass cell containing Ni-wire or the narrow gap of magnetic poles; the computational obtaining of immuno- parameters; binding constants, accumulation radius. Several biotechnological applications of the biosensor are presented on sorbent beads, human lymphocytes.

Comparison of three multiplex cytokine analysis systems: Luminex, SearchLight and FAST Quant.

PubMed

Lash, Gendie E; Scaife, Paula J; Innes, Barbara A; Otun, Harry A; Robson, Steven C; Searle, Roger F; Bulmer, Judith N

2006-02-20

Multiplex cytokine analysis technologies have become readily available in the last five years. Two main formats exist: multiplex sandwich ELISA and bead based assays. While these have each been compared to individual ELISAs, there has been no direct comparison between the two formats. We report here the comparison of two multiplex sandwich ELISA procedures (FAST Quant and SearchLight) and a bead based assay (UpState Luminex). All three kits differed from each other for different analytes and there was no clear pattern of one system giving systematically different results than another for any analyte studied. We suggest that each system has merits and several factors including range of analytes available, prospect of development of new analytes, dynamic range of the assay, sensitivity of the assay, cost of equipment, cost of consumables, ease of use and ease of data analysis need to be considered when choosing a system for use. We also suggest that results obtained from different systems cannot be combined.

Nitrate decontamination through functionalized chitosan in brackish water.

PubMed

Appunni, Sowmya; Rajesh, Mathur P; Prabhakar, Sivaraman

2016-08-20

N, N, N-Triethyl ammonium functionalized cross-linked chitosan beads (TEACCB) was prepared by alkylation of glutaraldehyde cross-linked chitosan beads to remove nitrate from brackish water. Physico-chemical characteristics of TEACCB were analyzed using FTIR, SEM, EDAX, TGA, DTA, BET surface area, swelling ratio and pHzpc. The maximum nitrate removal capacity of TEACCB was 2.26meq/g and is higher than other reported chitosan based adsorbents. Nitrate removal ratio in the presence and absence of common anions like chloride and sulphate demonstrated the selectively of TEACCB towards nitrate. The kinetic data of nitrate removal fitted well with the pseudo-second-order kinetic model. The thermodynamic parameters indicated that nitrate removal could be spontaneous and exothermic in nature. TEACCB was reused with 100% efficiency after regenerating with 0.05N HCl. Column study was carried out to remove nitrate from brackish water. These results are very significant to develop TEACCB based nitrate removal technology with great efficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Solution Chemistry on Nano-Bubbles Transport in Saturated Porous Media

NASA Astrophysics Data System (ADS)

Hamamoto, S.; Takemura, T.; Suzuki, K.; Nihei, N.; Nishimura, T.

2017-12-01

Nano-bubbles (NBs) have a considerable potential for the remediation of soil and groundwater contaminated by organic compounds, especially when used in conjunction with bioremediation technologies. Understanding the transport mechanisms of NBs in soils is essential to optimize NB-based remediation techniques. In this study, one-dimensional column transport experiments using glass beads with 0.1 mm size were conducted, where NBs created by oxygen gas at different pH and ionic strength were injected to the column at the constant flow rate. The NBs concentration in the effluent was quantified using a resonant mass measurement technique. Effects of solution chemistry of the NBs water on NB transport in the porous media were investigated. The results showed that attachment of NBs was enhanced under higher ionic strength and lower pH conditions, caused by the reduced repulsive force between NBs and glass beads. In addition, bubble size distributions in the effluents showed that relatively larger NBs were retained in the column. This trend was more significant at lower pH condition.

Preparation of Silk Sericin/Lignin Blend Beads for the Removal of Hexavalent Chromium Ions.

PubMed

Kwak, Hyo Won; Shin, Munju; Yun, Haesung; Lee, Ki Hoon

2016-09-02

In the present study, novel adsorbents having high adsorption capability and reusability were prepared using agricultural by-products: silk sericin and lignin. Silk sericin and lignin blend beads were successfully prepared using simple coagulation methods for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. A 1 M lithium chloride (LiCl)/dimethyl sulfoxide (DMSO) solvent system successfully dissolved both sericin and lignin and had sufficient viscosity for bead preparation. Compared to the conventional sericin bead adsorbent, sericin/lignin blend beads showed higher Cr(VI) adsorption capacity. The amount of lignin added to the adsorbent greatly affected the adsorption capacity of the beads, and a 50:50 sericin/lignin blend ratio was optimal. Adsorption behavior followed the Freundlich isotherm, which means the adsorption of Cr(VI) occurred on the heterogeneous surface. Cr(VI) adsorption capability increased with temperature because of thermodynamic-kinetic effects. In addition, over 90% of Cr(VI) ions were recovered from the Cr(VI) adsorbed sericin/lignin beads in a 1 M NaOH solution. The adsorption-desorption recycling process was stable for more than seven cycles, and the recycling efficiency was 82%. It is expected that the sericin/lignin beads could be successfully applied in wastewater remediation especially for hazardous Cr(VI) ions in industrial wastewater.

Preparation of Silk Sericin/Lignin Blend Beads for the Removal of Hexavalent Chromium Ions

PubMed Central

Kwak, Hyo Won; Shin, Munju; Yun, Haesung; Lee, Ki Hoon

2016-01-01

In the present study, novel adsorbents having high adsorption capability and reusability were prepared using agricultural by-products: silk sericin and lignin. Silk sericin and lignin blend beads were successfully prepared using simple coagulation methods for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. A 1 M lithium chloride (LiCl)/dimethyl sulfoxide (DMSO) solvent system successfully dissolved both sericin and lignin and had sufficient viscosity for bead preparation. Compared to the conventional sericin bead adsorbent, sericin/lignin blend beads showed higher Cr(VI) adsorption capacity. The amount of lignin added to the adsorbent greatly affected the adsorption capacity of the beads, and a 50:50 sericin/lignin blend ratio was optimal. Adsorption behavior followed the Freundlich isotherm, which means the adsorption of Cr(VI) occurred on the heterogeneous surface. Cr(VI) adsorption capability increased with temperature because of thermodynamic-kinetic effects. In addition, over 90% of Cr(VI) ions were recovered from the Cr(VI) adsorbed sericin/lignin beads in a 1 M NaOH solution. The adsorption-desorption recycling process was stable for more than seven cycles, and the recycling efficiency was 82%. It is expected that the sericin/lignin beads could be successfully applied in wastewater remediation especially for hazardous Cr(VI) ions in industrial wastewater. PMID:27598142

Transfer of Fas (CD95) protein from the cell surface to the surface of polystyrene beads coated with anti-Fas antibody clone CH-11

PubMed Central

Sawai, H.; Domae, N.

2010-01-01

Mouse monoclonal anti-Fas (CD95) antibody clone CH-11 has been widely used in research on apoptosis. CH-11 has the ability to bind to Fas protein on cell surface and induce apoptosis. Here, we used polystyrene beads coated with CH-11 to investigate the role of lipid rafts in Fas-mediated apoptosis in SKW6.4 cells. Unexpectedly, by treatment of the cells with CH-11-coated beads Fas protein was detached from cell surface and transferred to the surface of CH-11-coated beads. Western blot analysis showed that Fas protein containing both extracellular and intracellular domains was attached to the beads. Fas protein was not transferred from the cells to the surface of the beads coated with other anti-Fas antibodies or Fas ligand. Similar phenomenon was observed in Jurkat T cells. Furthermore, CH-11-induced apoptosis was suppressed by pretreatment with CH-11-coated beads in Jurkat cells. These results suggest that CH-11 might possess distinct properties on Fas protein compared with other anti-Fas antibodies or Fas ligand, and also suggest that caution should be needed to use polystyrene beads coated with antibodies such as CH-11. PMID:20353915

Quality assurance for sperm concentration using latex beads.

PubMed

Peters, A J; Zaneveld, L J; Jeyendran, R S

1993-10-01

To provide a simple, universally applicable method of quality assurance for sperm counting, thereby reducing intercounting chamber variation. By using a known concentration of latex beads, the sperm:bead ratio can be used to calculate the actual sperm count. The mean sperm and bead counts were determined in both a Spot-lite hemocytometer (Baxter Diagnostics, McGaw Park, IL) and a Makler chamber (Polymedco Inc., Yorktown, NY) from 21 different ejaculates mixed with a known concentration of beads. The hemocytometer chamber was used as the standard counting chamber because it consistently yielded a low variation in sperm count. The adjusted sperm concentration of the Makler chamber was calculated using the following formula [hemocytometer beads]/[Makler beads] x [Makler sperm]. Observed mean +/- SD sperm counts were significantly different between the hemocytometer chamber (110.6 +/- 66.2 x 10(6)/mL) and Makler chamber (173.3 +/- 103.5 x 10(6)/mL). However, calculated Makler chamber sperm counts (118.1 +/- 76.1 x 10(6)/mL) was not statistically different from observed hemocytometer sperm counts. This novel approach to sperm counting using a known concentration of latex beads as a reference material can be used to reduce variation in sperm counting between observers, counting chambers, and possibly computerized sperm analyzers.

Formulation and optimization of zinc-pectinate beads for the controlled delivery of resveratrol.

PubMed

Das, Surajit; Ng, Ka-Yun; Ho, Paul C

2010-06-01

Preventive and therapeutic efficacies of resveratrol on several lower gastrointestinal (GI) diseases (e.g., colorectal cancer, colitis) are well documented. To overcome the problems due to its rapid absorption and metabolism at the upper GI tract, a delayed release formulation of resveratrol was designed to treat these lower GI diseases. The current study aimed to develop a delayed release formulation of resveratrol as multiparticulate pectinate beads by varying different formulation parameters. Zinc-pectinate (Zn-pectinate) beads exhibited better delayed drug release pattern than calcium-pectinate (Ca-pectinate) beads. The effects of the formulation parameters were investigated on shape, size, Zn content, moisture content, drug encapsulation efficiency, swelling-erosion, and resveratrol retention pattern of the formulated beads. Upon optimization of the formulation parameters in relative to the drug release profiles, the optimized beads were further subjected to morphological, chemical interaction, enzymatic degradation, and stability studies. Almost all prepared beads were spherical with approximately 1 mm diameter and efficiently encapsulated resveratrol. The formulation parameters revealed great influence on resveratrol retention and swelling-erosion behavior. In most of the cases, the drug release data more appropriately fitted with zero-order equation. This study demonstrates that the optimized Zn-pectinate beads can encapsulate very high amount of resveratrol and can be used as delayed release formulation of resveratrol.

Impact of Microplastic Beads and Fibers on Waterflea (Ceriodaphnia dubia) Survival, Growth, and Reproduction: Implications of Single and Mixture Exposures.

PubMed

Ziajahromi, Shima; Kumar, Anupama; Neale, Peta A; Leusch, Frederic D L

2017-11-21

There is limited knowledge regarding the adverse effects of wastewater-derived microplastics, particularly fibers, on aquatic biota. In this study, we examined the acute (48 h) and chronic (8 d) effects of microplastic polyester fibers and polyethylene (PE) beads on freshwater zooplankton Ceriodaphnia dubia. We also assessed the acute response of C. dubia to a binary mixture of microplastic beads and fibers for the first time. Acute exposure to fibers and PE beads both showed a dose-dependent effect on survival. An equitoxic binary mixture of beads and fibers resulted in a toxic unit of 1.85 indicating less than additive effects. Chronic exposure to lower concentrations did not significantly affect survival of C. dubia, but a dose-dependent effect on growth and reproduction was observed. Fibers showed greater adverse effects than PE beads. While ingestion of fibers was not observed, scanning electron microscopy showed carapace and antenna deformities after exposure to fibers, with no deformities observed after exposure to PE beads. While much of the current research has focused on microplastic beads, our study shows that microplastic fibers pose a greater risk to C. dubia, with reduced reproductive output observed at concentrations within an order of magnitude of reported environmental levels.

Alginate and Algal-Based Beads for the Sorption of Metal Cations: Cu(II) and Pb(II)

PubMed Central

Wang, Shengye; Vincent, Thierry; Faur, Catherine; Guibal, Eric

2016-01-01

Alginate and algal-biomass (Laminaria digitata) beads were prepared by homogeneous Ca ionotropic gelation. In addition, glutaraldehyde-crosslinked poly (ethyleneimine) (PEI) was incorporated into algal beads. The three sorbents were characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX): the sorption occurs in the whole mass of the sorbents. Sorption experiments were conducted to evaluate the impact of pH, sorption isotherms, and uptake kinetics. A special attention was paid to the effect of drying (air-drying vs. freeze-drying) on the mass transfer properties. For alginate, freeze drying is required for maintaining the porosity of the hydrogel, while for algal-based sorbents the swelling of the material minimizes the impact of the drying procedure. The maximum sorption capacities observed from experiments were 415, 296 and 218 mg Pb g−1 and 112, 77 and 67 mg Cu g−1 for alginate, algal and algal/PEI beads respectively. Though the sorption capacities of algal-beads decreased slightly (compared to alginate beads), the greener and cheaper one-pot synthesis of algal beads makes this sorbent more competitive for environmental applications. PEI in algal beads decreases the sorption properties in the case of the sorption of metal cations under selected experimental conditions. PMID:27598128

BeadArray Expression Analysis Using Bioconductor

PubMed Central

Ritchie, Matthew E.; Dunning, Mark J.; Smith, Mike L.; Shi, Wei; Lynch, Andy G.

2011-01-01

Illumina whole-genome expression BeadArrays are a popular choice in gene profiling studies. Aside from the vendor-provided software tools for analyzing BeadArray expression data (GenomeStudio/BeadStudio), there exists a comprehensive set of open-source analysis tools in the Bioconductor project, many of which have been tailored to exploit the unique properties of this platform. In this article, we explore a number of these software packages and demonstrate how to perform a complete analysis of BeadArray data in various formats. The key steps of importing data, performing quality assessments, preprocessing, and annotation in the common setting of assessing differential expression in designed experiments will be covered. PMID:22144879

Development and evaluation of spherical molecularly imprinted polymer beads.

PubMed

Kempe, Henrik; Kempe, Maria

2006-06-01

The majority of studies on molecularly imprinted polymers has until now been carried out on irregularly shaped particles prepared by grinding of polymer monoliths. The preparation procedures are time- and labor-consuming and produce particles of wide size distributions. To answer the need for fast and straightforward routes to spherical molecularly imprinted polymer beads, we have developed a method comprising the formation of droplets of pre-polymerization solution directly in mineral oil by vigorous mixing followed by transformation of the droplets into solid spherical beads by photoinduced free-radical polymerization. No detergents or stabilizers were required for the droplet formation. Factors influencing the bead synthesis have been investigated and are detailed here. The beads were evaluated in parallel with corresponding irregularly shaped particles prepared from polymer monoliths. Conditions for the synthesis of propranolol-imprinted poly(methacrylic acid-co-trimethylolpropane trimethacrylate) beads in the size range of 1-100 microm in almost quantitative yield are described. The beads were applied as the recognition element in a 96-well plate format radioligand assay of propranolol in human serum.

Two-bead polarizable water models combined with a two-bead multipole force field (TMFF) for coarse-grained simulation of proteins.

PubMed

Li, Min; Zhang, John Z H

2017-03-08

The development of polarizable water models at coarse-grained (CG) levels is of much importance to CG molecular dynamics simulations of large biomolecular systems. In this work, we combined the newly developed two-bead multipole force field (TMFF) for proteins with the two-bead polarizable water models to carry out CG molecular dynamics simulations for benchmark proteins. In our simulations, two different two-bead polarizable water models are employed, the RTPW model representing five water molecules by Riniker et al. and the LTPW model representing four water molecules. The LTPW model is developed in this study based on the Martini three-bead polarizable water model. Our simulation results showed that the combination of TMFF with the LTPW model significantly stabilizes the protein's native structure in CG simulations, while the use of the RTPW model gives better agreement with all-atom simulations in predicting the residue-level fluctuation dynamics. Overall, the TMFF coupled with the two-bead polarizable water models enables one to perform an efficient and reliable CG dynamics study of the structural and functional properties of large biomolecules.

Insights on novel particulate self-assembled drug delivery beads based on partial inclusion complexes between triglycerides and cyclodextrins.

PubMed

Aburahma, Mona Hassan

2016-09-01

Most of the newly designed drug molecules are lipophilic in nature and often encounter erratic absorption and low bioavailability after oral administration. Finding ways to enhance the absorption and bioavailability of these lipophilic drugs is one of the major challenges that face pharmaceutical industry nowadays. In view of that, the purpose of this review is to shed some light on a novel particulate self-assembling system named "beads" than can act as a safe carrier for delivering lipophilic drugs. The beads are prepared simply by mixing oils with cyclodextrin (CD) aqueous solution in mild conditions. A unique interaction between oil components and CD molecules occurs to form in situ surface-active complexes which are prerequisites for beads formation. This review mainly focuses on the fundamentals of beads preparation through reviewing present, yet scarce, literature. The key methods used for beads characterization are discussed in details. Also, the potential mechanisms by which beads increase the bioavailability of lipophilic drugs are illustrated. Finally, the related research areas that needs to be addressed in future for optimizing this promising delivery system are briefly outlined.

Formulation optimization and evaluation of jackfruit seed starch-alginate mucoadhesive beads of metformin HCl.

PubMed

Nayak, Amit Kumar; Pal, Dilipkumar

2013-08-01

The present study deals with the formulation optimization of jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-alginate mucoadhesive beads containing metformin HCl through ionotropic gelation using 3(2) factorial design. The effect of sodium alginate to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release at 10h (R10h, %) was optimized. The optimized beads containing metformin HCl showed DEE of 97.48±3.92%, R10h of 65.70±2.22%, and mean diameter of 1.16±0.11mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads were influenced by pH of the test medium. The optimized beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier B.V. All rights reserved.

Dynamic trajectory analysis of superparamagnetic beads driven by on-chip micromagnets

PubMed Central

Abedini-Nassab, Roozbeh; Lim, Byeonghwa; Yang, Ye; Howdyshell, Marci; Sooryakumar, Ratnasingham; Yellen, Benjamin B.

2015-01-01

We investigate the non-linear dynamics of superparamagnetic beads moving around the periphery of patterned magnetic disks in the presence of an in-plane rotating magnetic field. Three different dynamical regimes are observed in experiments, including (1) phase-locked motion at low driving frequencies, (2) phase-slipping motion above the first critical frequency fc1, and (3) phase-insulated motion above the second critical frequency fc2. Experiments with Janus particles were used to confirm that the beads move by sliding rather than rolling. The rest of the experiments were conducted on spherical, isotropic magnetic beads, in which automated particle position tracking algorithms were used to analyze the bead dynamics. Experimental results in the phase-locked and phase-slipping regimes correlate well with numerical simulations. Additional assumptions are required to predict the onset of the phase-insulated regime, in which the beads are trapped in closed orbits; however, the origin of the phase-insulated state appears to result from local magnetization defects. These results indicate that these three dynamical states are universal properties of bead motion in non-uniform oscillators. PMID:26648596

Calibration beads containing luminescent lanthanide ion complexes

EPA Science Inventory

The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

Observation and Kinematic Description of Long Actin Tracks Induced by Spherical Beads

PubMed Central

Kang, Hyeran; Perlmutter, David S.; Shenoy, Vivek B.; Tang, Jay X.

2010-01-01

We report an in vitro study comparing the growth of long actin tails induced by spherical beads coated with the verprolin central acidic domain of the polymerization enzyme N-WASP to that induced by Listeria monocytogenes in similar cellular extracts. The tracks behind the beads show characteristic differences in shape and curvature from those left by the bacteria, which have an elongated shape and a similar polymerization-inducing enzyme distributed only on the rear surface of the cell. The experimental tracks are simulated using a generalized kinematic model, which incorporates three modes of bead rotation with respect to the tail. The results show that the trajectories of spherical beads are mechanically deterministic rather than random, as suggested by stochastic models. Assessment of the bead rotation and its mechanistic basis offers insights into the biological function of actin-based motility. PMID:21044576

Hollow polydimethylsiloxane beads with a porous structure for cell encapsulation.

PubMed

Oh, Myeong-Jin; Ryu, Tae-Kyoung; Choi, S-W

2013-11-01

Based on a water-in-oil-in-water emulsion system, porous and hollow polydimethylsiloxane (PDMS) beads containing cells using a simple fluidic device with three flow channels are fabricated. Poly(ethylene glycol) (PEG) in the PDMS oil phase is served as a porogen for pore development. The feasibility of the porous PDMS beads prepared with different PEG concentrations (10, 20, and 30 wt%) for cell encapsulation in terms of pore size, protein diffusion, and cell proliferation inside the PDMS beads is evaluated. The PDMS beads prepared with PEG 30 wt% are exhibited a highly porous structure and facilitated fast diffusion of protein from the core domain to the outer phase, eventually leading to enhanced cell proliferation. The results clearly indicate that hollow PDMS beads with a porous structure could provide a favorable microenvironment for cell survival due to the large porous structure. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microinjection - a tool to study gravitropism

NASA Astrophysics Data System (ADS)

Scherp, P.; Hasenstein, K. H.

2003-05-01

Despite extensive studies on plant gravitropism this phenomenon is still poorly understood. The separation of gravity sensing, signal transduction and response is a common concept but especially the mechanism of gravisensing remains unclear. This paper focuses on microinjection as powerful tool to investigate gravisensing in plants. We describe the microinjection of magnetic beads in rhizoids of the green alga Chara and related subsequent manipulation of the gravisensing system. After injection, an external magnet can control the movement of the magnetic beads. We demonstrate successful injection of magnetic beads into rhizoids and describe a multitude of experiments that can be carried out to investigate gravitropism in Chara rhizoids. In addition to examining mechanical properties, bead microinjection is also useful for probing the function of the cytoskeleton by coating beads with drugs that interfere with the cytoskeleton. The injection of fluorescently labeled beads or probes may reveal the involvement of the cytoskeleton during gravistimulation and response in living cells.

Increased Growth of the Microalga Chlorella vulgaris when Coimmobilized and Cocultured in Alginate Beads with the Plant-Growth-Promoting Bacterium Azospirillum brasilense†

PubMed Central

Gonzalez, Luz E.; Bashan, Yoav

2000-01-01

Coimmobilization of the freshwater microalga Chlorella vulgaris and the plant-growth-promoting bacterium Azospirillum brasilense in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of A. brasilense. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments. PMID:10742237

An integrated microfluidic cell for detection, manipulation, and sorting of single micron-sized magnetic beads

NASA Astrophysics Data System (ADS)

Jiang, Z.; Llandro, J.; Mitrelias, T.; Bland, J. A. C.

2006-04-01

A lab-on-a-chip integrated microfluidic cell has been developed for magnetic biosensing, which is comprised of anisotropic magnetoresistance (AMR) sensors optimized for the detection of single magnetic beads and electrodes to manipulate and sort the beads, integrated into a microfluidic channel. The device is designed to read out the real-time signal from 9 μm diameter magnetic beads moving over AMR sensors patterned into 18×4.5 μm rectangles and 10 μm diameter rings and arranged in Wheatstone bridges. The beads are moved over the sensors along a 75×75 μm wide channel patterned in SU8. Beads of different magnetic moments can be sorted through a magnetostatic sorting gate into different branches of the microfluidic channel using a magnetic field gradient applied by lithographically defined 120 nm thick Cu striplines carrying 0.2 A current.

Sexual Equality--An Increasingly Important Theme of Swedish Education Today.

ERIC Educational Resources Information Center

Western European Education, 1988

1988-01-01

Discusses Swedish efforts to promote sexual equality by enhancing female interest in technology rather than traditional female employment. Examines programs designed for students aged 7-20 and recognizes the need for inservice teacher training. Equating economic equality with sexual equality, the goal is to encourage females to pursue technical…

Improving efficiency of a small forensic DNA laboratory: validation of robotic assays and evaluation of microcapillary array device.

PubMed

Crouse, Cecelia A; Yeung, Stephanie; Greenspoon, Susan; McGuckian, Amy; Sikorsky, Julie; Ban, Jeff; Mathies, Richard

2005-08-01

To present validation studies performed for the implementation of existing and new technologies to increase the efficiency in the forensic DNA Section of the Palm Beach County Sheriff's Office (PBSO) Crime Laboratory. Using federally funded grants, internal support, and an external Process Mapping Team, the PBSO collaborated with forensic vendors, universities, and other forensic laboratories to enhance DNA testing procedures, including validation of the DNA IQ magnetic bead extraction system, robotic DNA extraction using the BioMek2000, the ABI7000 Sequence Detection System, and is currently evaluating a micro Capillary Array Electrophoresis device. The PBSO successfully validated and implemented both manual and automated Promega DNA IQ magnetic bead extractions system, which have increased DNA profile results from samples with low DNA template concentrations. The Beckman BioMek2000 DNA robotic workstation has been validated for blood, tissue, bone, hair, epithelial cells (touch evidence), and mixed stains such as semen. There has been a dramatic increase in the number of samples tested per case since implementation of the robotic extraction protocols. The validation of the ABI7000 real-time quantitative polymerase chain reaction (qPCR) technology and the single multiplex short tandem repeat (STR) PowerPlex16 BIO amplification system has provided both a time and a financial benefit. In addition, the qPCR system allows more accurate DNA concentration data and the PowerPlex 16 BIO multiplex generates DNA profiles data in half the time when compared to PowerPlex1.1 and PowerPlex2.1 STR systems. The PBSO's future efficiency requirements are being addressed through collaboration with the University of California at Berkeley and the Virginia Division of Forensic Science to validate microcapillary array electrophoresis instrumentation. Initial data demonstrated the electrophoresis of 96 samples in less than twenty minutes. The PBSO demonstrated, through the validation of more efficient extraction and quantification technology, an increase in the number of evidence samples tested using robotic/DNA IQ magnetic bead DNA extraction, a decrease in the number of negative samples amplified due to qPCR and implementation of a single multiplex amplification system. In addition, initial studies show the microcapillary array electrophoresis device (microCAE) evaluation results provide greater sensitivity and faster STR analysis output than current platforms.

Treating inertia in passive microbead rheology.

PubMed

Indei, Tsutomu; Schieber, Jay D; Córdoba, Andrés; Pilyugina, Ekaterina

2012-02-01

The dynamic modulus G(*) of a viscoelastic medium is often measured by following the trajectory of a small bead subject to Brownian motion in a method called "passive microbead rheology." This equivalence between the positional autocorrelation function of the tracer bead and G(*) is assumed via the generalized Stokes-Einstein relation (GSER). However, inertia of both bead and medium are neglected in the GSER so that the analysis based on the GSER is not valid at high frequency where inertia is important. In this paper we show how to treat both contributions to inertia properly in one-bead passive microrheological analysis. A Maxwell fluid is studied as the simplest example of a viscoelastic fluid to resolve some apparent paradoxes of eliminating inertia. In the original GSER, the mean-square displacement (MSD) of the tracer bead does not satisfy the correct initial condition. If bead inertia is considered, the proper initial condition is realized, thereby indicating an importance of including inertia, but the MSD oscillates at a time regime smaller than the relaxation time of the fluid. This behavior is rather different from the original result of the GSER and what is observed. What is more, the discrepancy from the GSER result becomes worse with decreasing bead mass, and there is an anomalous gap between the MSD derived by naïvely taking the zero-mass limit in the equation of motion and the MSD for finite bead mass as indicated by McKinley et al. [J. Rheol. 53, 1487 (2009)]. In this paper we show what is necessary to take the zero-mass limit of the bead safely and correctly without causing either the inertial oscillation or the anomalous gap, while obtaining the proper initial condition. The presence of a very small purely viscous element can be used to eliminate bead inertia safely once included in the GSER. We also show that if the medium contains relaxation times outside the window where the single-mode Maxwell behavior is observed, the oscillation can be attenuated inside the window. This attenuation is realized even in the absence of a purely viscous element. Finally, fluid inertia also affects the bead autocorrelation through the Basset force and the fluid dragged around with the bead. We show that the Basset force plays the same role as the purely viscous element in high-frequency regime, and the oscillation of MSD is suppressed if fluid density and bead density are comparable. © 2012 American Physical Society

Enhanced chitosan beads-supported Fe(0)-nanoparticles for removal of heavy metals from electroplating wastewater in permeable reactive barriers.

PubMed

Liu, Tingyi; Yang, Xi; Wang, Zhong-Liang; Yan, Xiaoxing

2013-11-01

The removal of heavy metals from electroplating wastewater is a matter of paramount importance due to their high toxicity causing major environmental pollution problems. Nanoscale zero-valent iron (NZVI) became more effective to remove heavy metals from electroplating wastewater when enhanced chitosan (CS) beads were introduced as a support material in permeable reactive barriers (PRBs). The removal rate of Cr (VI) decreased with an increase of pH and initial Cr (VI) concentration. However, the removal rates of Cu (II), Cd (II) and Pb (II) increased with an increase of pH while decreased with an increase of their initial concentrations. The initial concentrations of heavy metals showed an effect on their removal sequence. Scanning electron microscope images showed that CS-NZVI beads enhanced by ethylene glycol diglycidyl ether (EGDE) had a loose and porous surface with a nucleus-shell structure. The pore size of the nucleus ranged from 19.2 to 138.6 μm with an average aperture size of around 58.6 μm. The shell showed a tube structure and electroplating wastewaters may reach NZVI through these tubes. X-ray photoelectron spectroscope (XPS) demonstrated that the reduction of Cr (VI) to Cr (III) was complete in less than 2 h. Cu (II) and Pb (II) were removed via predominant reduction and auxiliary adsorption. However, main adsorption and auxiliary reduction worked for the removal of Cd (II). The removal rate of total Cr, Cu (II), Cd (II) and Pb (II) from actual electroplating wastewater was 89.4%, 98.9%, 94.9% and 99.4%, respectively. The findings revealed that EGDE-CS-NZVI-beads PRBs had the capacity to remediate actual electroplating wastewater and may become an effective and promising technology for in situ remediation of heavy metals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microcinematographic analysis of tethered Leptospira illini.

PubMed Central

Charon, N W; Daughtry, G R; McCuskey, R S; Franz, G N

1984-01-01

A model of Leptospira motility was recently proposed. One element of the model states that in translating cells the anterior spiral-shaped end gyrates counterclockwise and the posterior hook-shaped end gyrates clockwise. We tested these predictions by analyzing cells tethered to a glass surface. Leptospira illini was incubated with antibody-coated latex beads (Ab-beads). These beads adhered to the cells, and subsequently some cells became attached to either the slide or the cover glass via the Ab-beads. As previously reported, these cells rapidly moved back and forth across the surface of the beads. In addition, a general trend was observed: cells tethered to the cover glass rotated clockwise around the Ab-bead; cells tethered to the slide rotated counterclockwise around the Ab-bead. A computer-aided microcinematographic analysis of tethered cells indicated that the direction of rotation of cells around the Ab-bead was a function of both the surface of attachment and the shape of the cell ends. The results can best be explained by assuming that the gyrating ends interact with the glass surface to cause rotation around the Ab-beads. The analysis obtained indicates that the hook- and spiral-shaped ends rotate in the directions predicted by the model. In addition, the tethered cell assay permitted detection of rapid, coordinated reversals of the cell ends, e.g., cells rapidly switched from a hook-spiral configuration to a spiral-hook configuration. These results suggest the existance of a mechanism which coordinates the shape of the cell ends of L. illini. Images PMID:6501226

Development of the rectal dosage form with silver-coated glass beads for local-action applications in lower sections of the gastrointestinal tract.

PubMed

Siczek, Krzysztof; Fichna, Jakub; Zatorski, Hubert; Karolewicz, Bożena; Klimek, Leszek; Owczarek, Artur

2018-03-01

Recent findings indicating the anti-inflammatory action of silver preparations through modulation of the gut microbiota and apoptosis of inflammatory cells predestine silver use in inflammatory bowel disease (IBD). The aim of our study was to validate the possibility of effective silver release from silver-coated glass beads for anti-inflammatory local application in the lower sections of the gastrointestinal (GI) tract. Silver-coated glass beads were prepared using magnetron method. Release of silver from the silver-coated glass bead surface was carried out in BIO-DIS reciprocating cylinder apparatus. Erosion of silver coating and indirect estimation of the silver release dynamics was assessed using scanning electron microscope. Rectal suppositories containing silver-coated glass beads were prepared using five different methods (M1-M5) and X-ray scanned for their composition. The XR microanalysis and the chemical composition analysis evidenced for a rapid (within 30 min) release of nearly 50% of silver from the coating of the glass beads, which remained stable up to 24 h of incubation. The most homogeneous distribution of beads in the entire volume of the suppository was obtained for formulation M5, where the molten base was poured into mold placed in an ice bath, and the beads were added after 10 s. Our study is the first to present the concept of enclosing silver-coated glass beads in the lipophilic suppository base to attenuate inflammation in the lower GI tract and promises efficient treatment with reduced side effects.

Sorption Properties of Aerogel in Liquid Nitrogen

NASA Technical Reports Server (NTRS)

Johnson, Wesley L.

2006-01-01

Aerogel products are now available as insulation materials of the future. The Cryogenics Test Laboratory at the NASA Kennedy Space Center is developing aerogel-based thermal insulation systems for space launch applications. Aerogel beads (Cabot Nanogel ) and aerogel blankets (Aspen Aerogels Spaceloft ) have outstanding ambient pressure thermal performance that makes them useful for applications where sealing is not possible. Aerogel beads are open-celled silicone dioxide and have tiny pores that run throughout the body of the bead. It has also recently been discovered that aerogel beads can be used as a filtering device for aqueous compounds at room temperature. With their hydrophobic covering, the beads absorb any non-polar substance and they can be chemically altered to absorb hot gases. The combination of the absorption and cryogenic insulating properties of aerogel beads have never been studied together. For future cryogenic insulation applications, it is crucial to know how the beads react while immersed in cryogenic liquids, most notably liquid nitrogen. Aerogel beads in loose-fill situation and aerogel blankets with composite fiber structure have been tested for absorption properties. Depending on the type of aerogel used and the preparation, preliminary results show the material can absorb up to seven times its own weight of liquid nitrogen, corresponding to a volumetric ratio of 0.70 (unit volume nitrogen per unit volume aerogel). These tests allow for an estimate on how much insulation is needed in certain situations. The theory behind the different processes of sorption is necessary for a better understanding of the preparation of the beads before they are used in an insulation system.

Digital Detection of Multiple Minority Mutants and Expression Levels of Multiple Colorectal Cancer-Related Genes Using Digital-PCR Coupled with Bead-Array

PubMed Central

Huang, Huan; Li, Shuo; Sun, Lizhou; Zhou, Guohua

2015-01-01

To simultaneously analyze mutations and expression levels of multiple genes on one detection platform, we proposed a method termed “multiplex ligation-dependent probe amplification–digital amplification coupled with hydrogel bead-array” (MLPA–DABA) and applied it to diagnose colorectal cancer (CRC). CRC cells and tissues were sampled to extract nucleic acid, perform MLPA with sequence-tagged probes, perform digital emulsion polymerase chain reaction (PCR), and produce a hydrogel bead-array to immobilize beads and form a single bead layer on the array. After hybridization with fluorescent probes, the number of colored beads, which reflects the abundance of expressed genes and the mutation rate, was counted for diagnosis. Only red or green beads occurred on the chips in the mixed samples, indicating the success of single-molecule PCR. When a one-source sample was analyzed using mixed MLPA probes, beads of only one color occurred, suggesting the high specificity of the method in analyzing CRC mutation and gene expression. In gene expression analysis of a CRC tissue from one CRC patient, the mutant percentage was 3.1%, and the expression levels of CRC-related genes were much higher than those of normal tissue. The highly sensitive MLPA–DABA succeeds in the relative quantification of mutations and gene expressions of exfoliated cells in stool samples of CRC patients on the same chip platform. MLPA–DABA coupled with hydrogel bead-array is a promising method in the non-invasive diagnosis of CRC. PMID:25880764

Fabrication of a microfluidic device for studying the in situ drug-loading/release behavior of graphene oxide-encapsulated hydrogel beads.

PubMed

Veerla, Sarath Chandra; Kim, Da Reum; Yang, Sung Yun

2018-01-01

Controlled drug delivery system is highly important for not only prolonged the efficacy of drug but also cellular development for tissue engineering. A number of biopolymer composites and nanostructured carriers behave been used for the controlled drug delivery of therapeutics. Recently, in vitro microfluidic devices that mimic the human body have been developed for drug-delivery applications. A microfluidic channel was fabricated via a two-step process: (i) polydimethyl siloxane (PDMS) and curing agent were poured with a 10:2 mass ratio onto an acrylic mold with two steel pipes, and (ii) calcium alginate beads were synthesized using sodium alginate and calcium chloride solutions. Different amounts (10, 25, 50 μg) of graphene oxide (GO) were then added by Hummers method, and studies on the encapsulation and release of the model drug, risedronate (Ris), were performed using control hydrogel beads (pH 6.3), GO-containing beads (10GO, 25GO and 50GO), and different pH conditions. MC3T3 osteoblastic cells were cultured in a microchannel with Ris-loaded GO-hydrogel beads, and their proliferation, viability, attachment and spreading were assessed for a week. The spongy and textured morphology of pristine hydrogel beads was converted to flowery and rod-shaped structures in drug-loaded hydrogel beads at reduced pH (6.3) and at a lower concentration (10 μg) of GO. These latter 10GO drug-loaded beads rapidly released their cargo owing to the calcium phosphate deposited on the surface. Notably, beads containing a higher amount of GO (50GO) exhibited an extended drug-release profile. We further found that MC3T3 cells proliferated continuously in vitro in the microfluidic channel containing the GO-hydrogel system. MTT and live/dead assays showed similar proliferative potential of MC3T3 cells. Therefore, a microfluidic device with microchannels containing hydrogel beads formulated with different amounts of GO and tested under various pH conditions could be a promising system for controlled drug release. The GO and drug (risedronate, Rig) were directed loaded into a hydrogel placed in a microchannel. Through interactions such as hydrogen bonding between Go and the Rig-loaded GO-hydrogel beads, the bead-loaded microfluidic device supported MC3T3 proliferation and development as osteoblast without additional osteogenic differentiation supplements.

Study of The Effect of Draw-bead Geometry on Stretch Flange Formability

NASA Astrophysics Data System (ADS)

Orlov, O. S.; Winkler, S. L.; Worswick, M. J.; Lloyd, D. J.; Finn, M. J.

2004-06-01

A fully instrumented stretch flange press equipped with a back-up punch and draw-beads near the specimen cutout area is simulated. The utilization of different draw-bead geometries is examined numerically to determine the restraining forces, strains and amount of damage generated in stretch flanges during forming. Simulations of the forming process are conducted for 1mm AA5182 sheets with circular cutouts. The damage evolution with the deformed specimens is investigated using the explicit dynamic finite element code, LS-DYNA, with a modified Gurson-based material model. It was found that double draw-beads can provide the same amount of restraining force as single draw-beads, but at reduced levels of damage.

Local Antibiotic Delivery by a Bioabsorbable Gel Is Superior to PMMA Bead Depot in Reducing Infection in an Open Fracture Model

DTIC Science & Technology

2014-06-01

be achieved in the wound while avoiding the side effects and cost of systemic administration. Beads molded from polymethylmethacrylate cement are... polymethylmethacrylate antibiotic beads is less effective because this method has to rely on diffusion of the antibiotic from the high concentration close...antibiotics in clinical use is polymethylmethacrylate (PMMA) blended with antibiotics and molded into beads.6–8 There are, however, disadvantages

Continuous microwave regeneration apparatus for absorption media

DOEpatents

Smith, Douglas D.

1999-01-01

A method and apparatus for continuously drying and regenerating ceramic beads for use in process gas moisture drying operations such as glove boxes. A microwave energy source is coupled to a process chamber to internally heat the ceramic beads and vaporize moisture contained therein. In a preferred embodiment, the moisture laden ceramic beads are conveyed toward the microwave source by a screw mechanism. The regenerated beads flow down outside of the screw mechanism and are available to absorb additional moisture.

Pharmaceutical acrylic beads obtained by suspension polymerization containing cellulose nanowhiskers as excipient for drug delivery.

PubMed

Villanova, J C O; Ayres, E; Carvalho, S M; Patrício, P S; Pereira, F V; Oréfice, R L

2011-03-18

Direct compression is one of the most popular techniques to prepare tablets but only a few commercial excipients are well adapted for this process into controlled release formulations. In the last years, the introduction of new materials for drug delivery matrix tablets has become more important. This paper evaluated the physicochemical and flow properties of new polymeric excipient of ethyl acrylate, methyl methacrylate and butyl metacrylate, synthesized by suspension polymerization using cellulose nanowhiskers as co-stabilizer, to be used as direct compression for modified release tablets. Infrared spectroscopy (FTIR) confirmed the success of the copolymerization reaction. Scanning electron microscopy (SEM) showed that excipient was obtained how spherical beads. Thermal properties of the beads were characterized by thermogravimetric (TG) analysis. Particle size analysis of the beads with cellulose nanowhiskers (CNWB) indicated that the presence of the nanowhiskers led to a reduction of particle size and to a narrower size distribution. In vitro test showed that the nanowhiskers and beads produced are nontoxic. Parameters such as Hausner ratio, Carr's index and cotangent of angle α were employed to characterize the flow properties of CNWB beads. Furthermore, the beads are used to produce tablets by direct compression contained propranolol hydrochloride as model drug. Dissolution tests performed suggested that beads could be used as excipient in matrix tablets with a potential use in drug controlled release. Copyright © 2011 Elsevier B.V. All rights reserved.

Hot Forging of a Cladded Component by Automated GMAW Process

NASA Astrophysics Data System (ADS)

Rafiq, Muhammad; Langlois, Laurent; Bigot, Régis

2011-01-01

Weld cladding is employed to improve the service life of engineering components by increasing corrosion and wear resistance and reducing the cost. The acceptable multi-bead cladding layer depends on single bead geometry. Hence, in first step, the relationship between input process parameters and the single bead geometry is studied and in second step a comprehensive study on multi bead clad layer deposition is carried out. This paper highlights an experimental study carried out to get single layer cladding deposited by automated Gas Metal Arc Welding (GMAW) process and to find the possibility of hot forming of the cladded work piece to get the final hot formed improved structure. GMAW is an arc welding process that uses an arc between a consumable electrode and the welding pool with an external shielding gas and the cladding is done by alongside deposition of weld beads. The experiments for single bead were conducted by varying the three main process parameters wire feed rate, arc voltage and welding speed while keeping other parameters like nozzle to work distance, shielding gas and its flow rate and torch angle constant. The effect of bead spacing and torch orientation on the cladding quality of single layer from the results of single bead deposition was studied. Effect of the dilution rate and nominal energy on the cladded layer hot bending quality was also performed at different temperatures.

Fabrication and characterization of superporous cellulose bead for high-speed protein chromatography.

PubMed

Wang, Dong-Mei; Hao, Gang; Shi, Qing-Hong; Sun, Yan

2007-03-30

Novel superporous cellulose (SC) matrix has been fabricated by water-in-oil emulsification-thermal regeneration using granules of calcium carbonate as porogenic agents. As a control, microporous cellulose (MC) bead was fabricated in the absence of calcium carbonate. Simultaneously, double cross-linking was applied to enhance the mechanical strength of the particles. The photographs by scanning electron microscopy of the SC bead illustrated that there were more "craters" of several microns scattering on the surface of the beads. It led to a higher water content and effective porosity of the SC medium. The two beads were then modified with diethylaminoethyl (DEAE) group to prepare anion exchangers. The dynamic uptake results of bovine serum albumin (BSA) exhibited that the pore diffusivity of BSA in the DEAE-SC bead was two to three times larger than that in the DEAE-MC bead. In addition, the column packed with the DEAE-SC showed lower backpressure, higher column efficiency and dynamic binding capacity than the column packed with the DEAE-MC at a flow rate range of 150-900cm/h. Moreover, the column efficiency of the DEAE-SC column was independent of flow velocity up to a flow rate of 1200cm/h. All the results exhibited the superior characteristics of the SC bead as a potential medium for high-speed protein chromatography.

Ecohydraulics of Strings and Beads in Bedrock Rivers

NASA Astrophysics Data System (ADS)

Wohl, E.

2016-12-01

Twenty years ago, Jack Stanford and others described rivers in bedrock canyons as resembling beads on a string when viewed in planform. The beads are relatively wide, low gradient river segments with floodplains, whereas the strings are the intervening steep, narrow river segments with minimal floodplain development. This pattern of longitudinal variations in channel and valley morphology along bedrock canyon rivers is very common, from small channels to major rivers such as the Colorado. Basic understanding of river ecosystems, as well as limited studies, indicates that the beads are more retentive and biologically productive. Although both strings and beads can provide habitat for diverse organisms, strings are more likely to serve as migration corridors, whereas beads provide spawning and nursery habitat, facilitate lateral (channel-floodplain) and vertical (channel-hyporheic) exchanges and associated habitat diversity, and retain dissolved and particulate organic matter. Recognition of the different characteristics and functions of strings and beads can be used to identify their spatial distribution along a river or within a river network and the hydraulically driven processes that sustain channel form, water quality, and biota within strings and beads. Diverse modeling approaches can then be used to quantify the fluxes of water and sediment needed to maintain these hydraulically driven processes. This conceptual framework is illustrated using examples from mountain streams in the Southern Rockies and canyon rivers in the southwestern United States.

Micromagnet arrays for on-chip focusing, switching, and separation of superparamagnetic beads and single cells.

PubMed

Rampini, S; Kilinc, D; Li, P; Monteil, C; Gandhi, D; Lee, G U

2015-08-21

Nonlinear magnetophoresis (NLM) is a novel approach for on-chip transport and separation of superparamagnetic (SPM) beads, based on a travelling magnetic field wave generated by the combination of a micromagnet array (MMA) and an applied rotating magnetic field. Here, we present two novel MMA designs that allow SPM beads to be focused, sorted, and separated on-chip. Converging MMAs were used to rapidly collect the SPM beads from a large region of the chip and focus them into synchronised lines. We characterise the collection efficiency of the devices and demonstrate that they can facilitate on-chip analysis of populations of SPM beads using a single-point optical detector. The diverging MMAs were used to control the transport of the beads and to separate them based on their size. The separation efficiency of these devices was determined by the orientation of the magnetisation of the micromagnets relative to the external magnetic field and the size of the beads and relative to that of micromagnets. By controlling these parameters and the rotation of the external magnetic field we demonstrated the controlled transport of SPM bead-labelled single MDA-MB-231 cells. The use of these novel MMAs promises to allow magnetically-labelled cells to be efficiently isolated and then manipulated on-chip for analysis with high-resolution chemical and physical techniques.

Geochemical features of glass beads excavated from the Iron Age archaeological sites, Eastern Taiwan

NASA Astrophysics Data System (ADS)

Yang, H.

2016-12-01

The uses of metallic artifacts began 2500-2000 years ago in Taiwan; in the meanwhile glass beads have also been as a common ornament by the prehistoric people. Glass, as the earliest artificial ornament, is made by a mixture of quartz sands and flux which were heated to more than one thousand Celsius degrees. Therefore, the production processes, raw material provenance and exchange systems could be revealed by the chemical compositions of glass artifacts. The chemical composition of glass beads studies from four archaeological sites (PL, PN, CHL and TL sites) in early Iron Age are reported in this study. By the producing in drawn method and limited ranges of colors with various hue, all the studied glass beads here should be classified as Indo-Pacific glass beads. As these ancient glass beads are unique and precious, a non-destructive analytical method is always considered at the initial stage. Therefore, we use the best known and most widely-used of the surface analytical techniques SEM/EDX to get the surface and quantitative elemental information of glass beads. According to the analytical results, the PL and PN glass beads all belong to potassium silica glass and those coexisting with so-called Kueishan sherds excavated from CHL and TL sites should be classified as sodium-calcium glass which is the most general composition of Indo-Pacific glass beads. Not only the different flux using between potassium and sodium glass, the variation in the aluminum contents between potassium and sodium glass also exhibits different provenances of glass-making raw materials. As lack of glass-making remains in Taiwan, these ancient glass beads were considered as a precious and trading artifact to Taiwan from overseas and introduced into prehistoric societies via various sources and paths. Although the trading/exchange routes of ancient glass beads are still debatable, we find that compositional analyses can help answer such questions as what types of glass were used for their manufacture and with separate traditions and hope the results can give us some insight into the potential beadmaking sites and in addition to establish the exchange networks of prehistoric people.

Jllumina - A comprehensive Java-based API for statistical Illumina Infinium HumanMethylation450 and MethylationEPIC data processing.

PubMed

Almeida, Diogo; Skov, Ida; Lund, Jesper; Mohammadnejad, Afsaneh; Silva, Artur; Vandin, Fabio; Tan, Qihua; Baumbach, Jan; Röttger, Richard

2016-12-18

Measuring differential methylation of the DNA is the nowadays most common approach to linking epigenetic modifications to diseases (called epigenome-wide association studies, EWAS). For its low cost, its efficiency and easy handling, the Illumina HumanMethylation450 BeadChip and its successor, the Infinium MethylationEPIC BeadChip, is the by far most popular techniques for conduction EWAS in large patient cohorts. Despite the popularity of this chip technology, raw data processing and statistical analysis of the array data remains far from trivial and still lacks dedicated software libraries enabling high quality and statistically sound downstream analyses. As of yet, only R-based solutions are freely available for low-level processing of the Illumina chip data. However, the lack of alternative libraries poses a hurdle for the development of new bioinformatic tools, in particular when it comes to web services or applications where run time and memory consumption matter, or EWAS data analysis is an integrative part of a bigger framework or data analysis pipeline. We have therefore developed and implemented Jllumina, an open-source Java library for raw data manipulation of Illumina Infinium HumanMethylation450 and Infinium MethylationEPIC BeadChip data, supporting the developer with Java functions covering reading and preprocessing the raw data, down to statistical assessment, permutation tests, and identification of differentially methylated loci. Jllumina is fully parallelizable and publicly available at http://dimmer.compbio.sdu.dk/download.html.

High throughput imaging cytometer with acoustic focussing† †Electronic supplementary information (ESI) available: High throughput imaging cytometer with acoustic focussing. See DOI: 10.1039/c5ra19497k Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file.

PubMed Central

Zmijan, Robert; Jonnalagadda, Umesh S.; Carugo, Dario; Kochi, Yu; Lemm, Elizabeth; Packham, Graham; Hill, Martyn

2015-01-01

We demonstrate an imaging flow cytometer that uses acoustic levitation to assemble cells and other particles into a sheet structure. This technique enables a high resolution, low noise CMOS camera to capture images of thousands of cells with each frame. While ultrasonic focussing has previously been demonstrated for 1D cytometry systems, extending the technology to a planar, much higher throughput format and integrating imaging is non-trivial, and represents a significant jump forward in capability, leading to diagnostic possibilities not achievable with current systems. A galvo mirror is used to track the images of the moving cells permitting exposure times of 10 ms at frame rates of 50 fps with motion blur of only a few pixels. At 80 fps, we demonstrate a throughput of 208 000 beads per second. We investigate the factors affecting motion blur and throughput, and demonstrate the system with fluorescent beads, leukaemia cells and a chondrocyte cell line. Cells require more time to reach the acoustic focus than beads, resulting in lower throughputs; however a longer device would remove this constraint. PMID:29456838

Application of allflex conservation buffer in illumina genotyping.

PubMed

de Groot, M; Ras, T; van Haeringen, W A

2016-12-01

This experiment was designed to study if liquid conservation buffer used in the novel Tissue Sampling Technology (TST) from Allflex can be used for Illumina BeadChip genotyping. Ear punches were collected from 6 bovine samples, using both the Tissue Sampling Unit (TSU) as well as the Total Tagger Universal (TTU) collection system. The stability of the liquid conservation buffer was tested by genotyping samples on Illumina BeadChips, incubated at 0, 3, 15, 24, 48, 72, 168, 336, 720 h after sample collection. Additionally, a replenishment study was designed to test how often the liquid conservation buffer could be completely replenished before a significant call rate drop could be observed. Results from the stability study showed an average call rate of 0.993 for samples collected with the TSU system and 0.953 for samples collected with the TTU system, both exceeding the inclusion threshold call rate of 0.85. As an additional control, the identity of the individual animals was confirmed using the International Society of Animal Genetics (ISAG) recommended SNP panel. The replenishment study revealed a slight drop in the sample call rate after replenishing the conservation buffer for the fourth time for the TSU as well as the TTU samples. In routine analysis, this application allows for multiple experiments to be performed on the liquid conservation buffer, while maintaining the tissue samples for future use. The data collected in this study shows that the liquid conservation buffer used in the TST system can be used for Illumina BeadChip genotyping applications.

Design and fabrication of metallic thermal protection systems for aerospace vehicles

NASA Technical Reports Server (NTRS)

Varisco, A.; Bell, P.; Wolter, W.

1978-01-01

A program was conducted to develop a lightweight, efficient metallic thermal protection system (TPS) for application to future shuttle-type reentry vehicles, advanced space transports, and hypersonic cruise vehicles. Technical requirements were generally derived from the space shuttle. A corrugation-stiffened beaded-skin TPS design was used as a baseline. The system was updated and modified to incorporate the latest technology developments and design criteria. The primary objective was to minimize mass for the total system.

Edgewood Biosensors Test Bed Hand-held and Man-Portable Edition

DTIC Science & Technology

2013-09-01

Laboratories Antibody-based wave guide detection Antibody-based capture beads Seattle Sensor Systems 𔃺Ŕ’"𔃺’ Surface plasmon resonance 19  Approved...160  APPENDIX A: TECHNOLOGY READINESS ASSIGNMENTS .......................................................... A‐1  APPENDIX B: BIO ...Sandia National Laboratories’ SpinDx™, Seattle  Sensors  Systems’ SPIRIT™ and  the Research International RAPTOR scored poorly and assessed to be

Label-free voltammetric detection of MicroRNAs at multi-channel screen printed array of electrodes comparison to graphite sensors.

PubMed

Erdem, Arzum; Congur, Gulsah

2014-01-01

The multi-channel screen-printed array of electrodes (MUX-SPE16) was used in our study for the first time for electrochemical monitoring of nucleic acid hybridization related to different miRNA sequences (miRNA-16, miRNA-15a and miRNA-660, i.e, the biomarkers for Alzheimer disease). The MUX-SPE16 was also used for the first time herein for the label-free electrochemical detection of nucleic acid hybridization combined magnetic beads (MB) assay in comparison to the disposable pencil graphite electrode (PGE). Under the principle of the magnetic beads assay, the biotinylated inosine substituted DNA probe was firstly immobilized onto streptavidin coated MB, and then, the hybridization process between probe and its complementary miRNA sequence was performed at MB surface. The voltammetric transduction was performed using differential pulse voltammetry (DPV) technique in combination with the single-use graphite sensor technologies; PGE and MUX-SPE16 for miRNA detection by measuring the guanine oxidation signal without using any external indicator. The features of single-use sensor technologies, PGE and MUX-SPE16, were discussed concerning to their reproducibility, detection limit, and selectivity compared to the results in the earlier studies presenting the electrochemical miRNA detection related to different miRNA sequences. © 2013 Elsevier B.V. All rights reserved.

Dynamics assembly of magnetic microparticles suspended in moving droplets under the influence of magnetic fields

NASA Astrophysics Data System (ADS)

Strey, Helmut; Brouzes, Eric; Kruse, Travis

2013-03-01

Droplet microfluidics has experienced tremendous growth, particularly since it is well suited for single-cell manipulation and analysis. As mature methods for high throughput droplet manipulation have been developed a technological bottleneck of current droplet microfluidics is that because droplets are separated, sequential chemical reactions are more difficult to achieve. For example, it is very difficult to concentrate target molecules, especially since every reaction step adds volume to the droplets. Our solution to this problem is to employ functionalized magnetic beads inside droplets. The basic idea is that an external magnetic field could be used to concentrate the magnetic beads in one part of the droplet and those could then be extracted by splitting the droplet. Here we present an experimental study of the self-assembly of superparamagnetic microparticles that are suspended in moving droplets and experience a combination of forces due to the internal fluid flow fields and external magnetic fields. We observed that this interplay of flow fields coupled to the formation of particle assemblies leads to the formations of stable patterns depending on the flow speed and magnetic field strength. An understanding of this dynamic assembly is critical in employing external forces for applications in separation and sorting. Funding through NYSTAR, Center for Advanced Technology and a grant from NIH-NHGRI (1 R21 HG006206-01).

Measurement of cAMP in an undergraduate teaching laboratory, using ALPHAscreen technology.

PubMed

Bartho, Joseph D; Ly, Kien; Hay, Debbie L

2012-02-14

Adenosine 3',5'-monophosphate (cAMP) is a cellular second messenger with central relevance to pharmacology, cell biology, and biochemistry teaching programs. cAMP is produced from adenosine triphosphate by adenylate cyclase, and its production is reduced or enhanced upon activation of many G protein-coupled receptors. Therefore, the measurement of cAMP serves as an indicator of receptor activity. Although there are many assays available for measuring cAMP, few are suitable for large class teaching, and even fewer seem to have been adapted for this purpose. Here, we describe the use of bead-based ALPHAscreen (Amplified Luminescent Proximity Homogenous Assay) technology for teaching a class of more than 300 students the practical aspects of detecting signal transduction. This technology is applicable to the measurement of many different signaling pathways. This resource is designed to provide a practical guide for instructors and a useful model for developing other classes using similar technologies.

Equalizer technology followed by DIGE-based proteomics for detection of cellular proteins in artificial peritoneal dialysis effluents.

PubMed

Lichtenauer, Anton Michael; Herzog, Rebecca; Tarantino, Silvia; Aufricht, Christoph; Kratochwill, Klaus

2014-05-01

Peritoneal dialysis effluent (PDE) represents a rich pool of potential biomarkers for monitoring disease and therapy. Until now, proteomic studies have been hindered by the plasma-like composition of the PDE. Beads covered with a peptide library are a promising approach to remove high abundant proteins and concentrate the sample in one step. In this study, a novel approach for proteomic biomarker identification in PDEs consisting of a depletion and concentration step followed by 2D gel based protein quantification was established. To prove this experimental concept a model system of artificial PDEs was established by spiking unused peritoneal dialysis (PD) fluids with cellular proteins reflecting control conditions or cell stress. Using this procedure, we were able to reduce the amount of high abundant plasma proteins and concentrate low abundant proteins while preserving changes in abundance of proteins with cellular origin. The alterations in abundance of the investigated marker for cell stress, the heat shock proteins, showed similar abundance profiles in the artificial PDE as in pure cell culture samples. Our results demonstrate the efficacy of this system in detecting subtle changes in cellular protein expression triggered by unphysiological stress stimuli typical in PD, which could serve as biomarkers. Further studies using patients' PDE will be necessary to prove the concept in clinical PD and to assess whether this technique is also informative regarding enriching low abundant plasma derived protein biomarker in the PDE. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of Enzyme Co-Immobilization with Sodium Alginate and Glutaraldehyde-Activated Chitosan Beads.

PubMed

Gür, Sinem Diken; İdil, Neslihan; Aksöz, Nilüfer

2018-02-01

In this study, two different materials-alginate and glutaraldehyde-activated chitosan beads-were used for the co-immobilization of α-amylase, protease, and pectinase. Firstly, optimization of multienzyme immobilization with Na alginate beads was carried out. Optimum Na alginate and CaCl 2 concentration were found to be 2.5% and 0.1 M, respectively, and optimal enzyme loading ratio was determined as 2:1:0.02 for pectinase, protease, and α-amylase, respectively. Next, the immobilization of multiple enzymes on glutaraldehyde-activated chitosan beads was optimized (3% chitosan concentration, 0.25% glutaraldehyde with 3 h of activation and 3 h of coupling time). While co-immobilization was successfully performed with both materials, the specific activities of enzymes were found to be higher for the enzymes co-immobilized with glutaraldehyde-activated chitosan beads. In this process, glutaraldehyde was acting as a spacer arm. SEM and FTIR were used for the characterization of activated chitosan beads. Moreover, pectinase and α-amylase enzymes immobilized with chitosan beads were also found to have higher activity than their free forms. Three different enzymes were co-immobilized with these two materials for the first time in this study.

OBT analysis method using polyethylene beads for limited quantities of animal tissue.

PubMed

Kim, S B; Stuart, M

2015-08-01

This study presents a polyethylene beads method for OBT determination in animal tissues and animal products for cases where the amount of water recovered by combustion is limited by sample size or quantity. In the method, the amount of water recovered after combustion is enhanced by adding tritium-free polyethylene beads to the sample prior to combustion in an oxygen bomb. The method reduces process time by allowing the combustion water to be easily collected with a pipette. Sufficient water recovery was achieved using the polyethylene beads method when 2 g of dry animal tissue or animal product were combusted with 2 g of polyethylene beads. Correction factors, which account for the dilution due to the combustion water of the beads, are provided for beef, chicken, pork, fish and clams, as well as egg, milk and cheese. The method was tested by comparing its OBT results with those of the conventional method using animal samples collected on the Chalk River Laboratories (CRL) site. The results determined that the polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Wearable glass beads for in vivo dosimetry of total skin electron irradiation treatments

NASA Astrophysics Data System (ADS)

Nabankema, S. K.; Jafari, S. M.; Peet, S. C.; Binny, D.; Sylvander, S. R.; Crowe, S. B.

2017-11-01

Glass beads have recently been proposed for use as radiation therapy dosimeters. Glass beads have a number of characteristics that make them suitable for in vivo skin dose measurements, including an ability to be worn on a string, and therefore avoid possible patient discomfort that may result from the use of adhesives. In this study, their use for in vivo dose measurements in total skin electron irradiation treatments has been tested. First, the dosimetric properties of cylindrical beads with a 3 mm diameter were characterised using electron fields produced by a linear accelerator. The mean individual bead reproducibility was demonstrated to be within 3%; and a batch variation of 7% was observed. The beads were shown to have a linear dose response, and both dose rate and beam energy independence, within the measurement uncertainty. Phantom measurements were then performed for a total skin electron irradiation beam arrangement, and results compared against optically stimulated luminescent dosimeters at five anatomical sites. For a majority of measurement locations, agreement within 3% was observed between the two dosimetry techniques, demonstrating the feasibility of glass beads as in vivo dosimeters for total skin electron irradiation; though further investigation may be needed to minimise uncertainty in results.

Facile preparation and characterization of pH sensitive Mt/CMC nanocomposite hydrogel beads for propranolol controlled release.

PubMed

Farhadnejad, Hassan; Mortazavi, Seyed Alireza; Erfan, Mohammad; Darbasizadeh, Behzad; Motasadizadeh, Hamidreza; Fatahi, Yousef

2018-05-01

The main aim of the present study was to design pH-sensitive nanocomposite hydrogel beads, based on carboxymethyl cellulose (CMC) and montmorillonite (Mt)-propranolol (PPN) nanohybrid, and evaluate whether the prepared nanocomposite beads could potentially be used as oral drug delivery systems. PPN-as a model drug-was intercalated into the interlayer space of Mt clay mineral via the ion exchange procedure. The resultant nanohybrid (Mt-PPN) was applied to fabricate nanocomposite hydrogel beads by association with carboxymethyl cellulose. The characterization of test samples was performed using different techniques: X-Ray Diffraction (XRD), IR spectroscopy (FT-IR), thermal gravity analysis (TGA), and scanning electron microscopy (SEM). The drug encapsulation efficiency was evaluated by UV-vis spectroscopy, and was found to be high for Mt/CMC beads. In vitro drug release test was performed in the simulated gastrointestinal conditions to evaluate the efficiency of Mt-PPN/CMC nanocomposite beads as a controlled-release drug carrier. The drug release profiles indicated that the Mt-PPN/CMC nanocomposite beads had high stability against stomach acid and a sustained- and controlled-release profile for PPN under the simulated intestinal conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Use of micrometric latex beads to improve the porosity of hydroxyapatite obtained by chemical coprecipitation method

NASA Astrophysics Data System (ADS)

Webler, G. D.; Rodrigues, W. C.; Silva, A. E. S.; Silva, A. O. S.; Fonseca, E. J. S.; Degenhardt, M. F. S.; Oliveira, C. L. P.; Otubo, L.; Barros Filho, D. A.

2018-04-01

Hydroxyapatite is one of the most important biomaterials whose application mainly extends to implants and drug delivery. This work will discuss the changes in the pore size distribution of hydroxyapatite when there are latex beads present during the synthesis. These changes were monitored using different techniques: small angle X-ray scattering, X-ray diffraction, thermal gravimetrical analysis, N2 adsorption, scanning and transmission electron microscopy. Latex beads and hydroxyapatite form a single nanocomposite with well-distinguished inorganic and organic phases. Latex bead removal in the temperature range of 300-600 °C did not modify the original crystalline structure of hydroxyapatite. However, the latex beads favored an increase in the adsorption capacity of mesopores at temperatures higher than their glassy transition (Tg). The main result of this research work consists on the increase of surface area and pore size distribution obtained after the removal of latex beads template. Latex beads have been used in a different approach changing the porosity of hydroxyapatite scaffolds not only introducing new routes for cell integration but also broadening the pore size distribution which can result in a more high efficiency for drug release in living cells.

Artocarpus heterophyllus L. seed starch-blended gellan gum mucoadhesive beads of metformin HCl.

PubMed

Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

2014-04-01

Jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-gellan gum (GG) mucoadhesive beads containing metformin HCl were developed through ionotropic gelation technique. The effect of GG to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %) and cumulative drug release at 10h (R10h, %) was optimized and analyzed using response surface methodology based on 3(2) factorial design. The optimized JFSS-GG beads containing metformin HCl showed DEE of 92.67±4.46%, R10h of 61.30±2.37%, and mean diameter of 1.67±0.27 mm. The optimized beads showed pH-dependent swelling and mucoadhesivity with the goat intestinal mucosa. The in vitro drug release from all these JFSS-GG beads containing metformin HCl was followed zero-order pattern (R(2)=0.9907-0.9975) with super case-II transport mechanism over a period of 10 h. The beads were also characterized by SEM and FTIR. The optimized JFSS-GG beads containing metformin HCl exhibited significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2014 Elsevier B.V. All rights reserved.

Crosslinked, porous, polyacrylate beads

NASA Technical Reports Server (NTRS)

Rembaum, Alan (Inventor); Yen, Shiao-Ping Siao (Inventor); Dreyer, William J. (Inventor)

1976-01-01

Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

Crosslinked, porous, polyacrylate beads

NASA Technical Reports Server (NTRS)

Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

1977-01-01

Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree. C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

Measurement of retroreflection by glass beads for road marking

NASA Astrophysics Data System (ADS)

Ivanov, L. A.; Kiesewetter, D. V.; Kiselev, N. N.; Malyugin, V. I.; Slugin, V. A.

2006-04-01

The parameters of retroreflection of the monolayer of glass beads of the different size and quality in paint for road marking are measured. The new method of simultaneous measurement of the size and coefficient of retroreflection of separate beads is offered. The system of the statistical characteristics of optical quality is introduced. The measurements for different dimensional fractions are carried out. The capability of estimation of influencing of defects of glass beads on retro reflecting properties of the materials is shown.

Small, porous polyacrylate beads

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping Siao (Inventor); Rembaum, Alan (Inventor); Dreyer, William J. (Inventor)

1976-01-01

Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

Polymeric Beads for Organic Coatings

DTIC Science & Technology

1982-10-31

Clear Solid Polymeric Beads A solid polymeric bead is comprised of a sol id mass of polymerized unsaturated polyester/styrene resin mixture . 2. lear...than the current unsaturated polyester resin . For example, a bead male from acrylic resin could be more trans- - parent, more durable and provide more...0.44 Isopropyl Alcohol I 11.26 I 1 .73 60% Wt. Alkyd Resin - Volume I 251.26 i 30.52 " Sol ids 51% 1 I Anti.-Skinning Agent I 0.90 I 0.12 Mineral

Educational Technology: A Presupposition of Equality?

ERIC Educational Resources Information Center

Orlando, Joanne

2014-01-01

The work of philosopher Jacques Rancière is used conceptually and methodologically to frame an exploration of the driving interests in educational technology policy and the sanctioning of particular discursive constructions of pedagogy that result. In line with Rancière's thinking, the starting point for this analysis is that of equality--that…

Evaluation of in vitro serial antibiotic elution from meropenem-impregnated polymethylmethacrylate beads after ethylene oxide gas and autoclave sterilization.

PubMed

Báez, L A; Langston, C; Givaruangsawat, S; McLaughlin, R

2011-01-01

To determine the elution properties of meropenem and to compare the elutions of meropenem-impregnated polymethylmethacrylate (PMMA) beads without sterilization (P-M-C) to those sterilized with steam (P-M-A) and ethylene oxide gas (P-M-EO). A commercial bead mould was used to produce four groups of beads: one group without antibiotic (negative control), and three groups of meropenem-impregnated beads: P-M-C, P-M-A, and P-M-EO. The beads were placed in a phosphate buffered solution and eluent samples were collected. Concentrations of the antibiotic in eluent samples from the two sterilized groups and the control beads were determined using a microbiological assay at 1, 3, 6 and 12 hours and at 1, 2, 3, 6, 9, 12, 15, 18, 22, 26, and 30 days. The microbiological assay resulted in no zone of inhibition at all time periods for the P-M-A samples and the samples of PMMA without antimicrobial. The meropenem concentration on the eluent remained above 4 mcg/ml for 15 days in the P-M-C group and until day 18 for P-M-EO group. There was no statistical difference in AUC0-∞ (p<0.318), however significance did occur for MRT (p<0.005) when comparing P-M-C and P-M-EO with the later being higher. The meropenem incorporated in the PMMA beads eluted effectively and gradually decreased after the 24 hour peak, but remained above the concentration level of 4 mcg/ml for 15 days in the P-M-C group and until day 18 for P-M-EO group. Ethylene oxide does not adversely affect meropenem's elution from PMMA beads.

Plasma membrane isolation using immobilized concanavalin A magnetic beads.

PubMed

Lee, Yu-Chen; Srajer Gajdosik, Martina; Josic, Djuro; Lin, Sue-Hwa

2012-01-01

Isolation of highly purified plasma membranes is the key step in constructing the plasma membrane proteome. Traditional plasma membrane isolation method takes advantage of the differential density of organelles. While differential centrifugation methods are sufficient to enrich for plasma membranes, the procedure is lengthy and results in low recovery of the membrane fraction. Importantly, there is significant contamination of the plasma membranes with other organelles. The traditional agarose affinity matrix is suitable for isolating proteins but has limitation in separating organelles due to the density of agarose. Immobilization of affinity ligands to magnetic beads allows separation of affinity matrix from organelles through magnets and could be developed for the isolation of organelles. We have developed a simple method for isolating plasma membranes using lectin concanavalin A (ConA) magnetic beads. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. The ConA magnetic beads are used to bind glycosylated proteins present in the membranes. The bound membranes are solubilized from the magnetic beads with a detergent containing the competing sugar alpha methyl mannoside. In this study, we describe the procedure of isolating rat liver plasma membranes using sucrose density gradient centrifugation as described by Neville. We then further purify the membrane fraction by using ConA magnetic beads. After this purification step, main liver plasma membrane proteins, especially the highly glycosylated ones and proteins containing transmembrane domains could be identified by LC-ESI-MS/MS. While not described here, the magnetic bead method can also be used to isolate plasma membranes from cell lysates. This membrane purification method should expedite the cataloging of plasma membrane proteome.

Feasibility of using glass-bead thermoluminescent dosimeters for radiotherapy treatment plan verification.

PubMed

Jafari, Shakardokht M; Jordan, Tom J; Distefano, Gail; Bradley, David A; Spyrou, Nicholas M; Nisbet, Andrew; Clark, Catharine H

2015-01-01

To investigate the feasibility of using glass beads as novel thermoluminescent dosemeters (TLDs) for radiotherapy treatment plan verification. Commercially available glass beads with a size of 1-mm thickness and 2-mm diameter were characterized as TLDs. Five clinical treatment plans including a conventional larynx, a conformal prostate, an intensity-modulated radiotherapy (IMRT) prostate and two stereotactic body radiation therapy (SBRT) lung plans were transferred onto a CT scan of a water-equivalent phantom (Solid Water(®), Gammex, Middleton, WI) and the dose distribution recalculated. The number of monitor units was maintained from the clinical plan and delivered accordingly. The doses determined by the glass beads were compared with those measured by a graphite-walled ionization chamber, and the respective expected doses were determined by the treatment-planning system (TPS) calculation. The mean percentage difference between measured dose with the glass beads and TPS was found to be 0.3%, -0.1%, 0.4%, 1.8% and 1.7% for the conventional larynx, conformal prostate, IMRT prostate and each of the SBRT delivery techniques, respectively. The percentage difference between measured dose with the ionization chamber and glass bead was found to be -1.2%, -1.4%, -0.1%, -0.9% and 2.4% for the above-mentioned plans, respectively. The results of measured doses with the glass beads and ionization chamber in comparison with expected doses from the TPS were analysed using a two-sided paired t-test, and there was no significant difference at p < 0.05. It is feasible to use glass-bead TLDs as dosemeters in a range of clinical plan verifications. Commercial glass beads are utilized as low-cost novel TLDs for treatment-plan verification.

Effect of pH and polypropylene beads in hybrid water treatment process of alumina ceramic microfiltration and PP beads with air back-flushing and UV irradiation.

PubMed

Park, Jin Yong; Song, Seunghwa

2017-07-07

For advanced water treatment, effects of pH and pure polypropylene (PP) beads packing concentration on membrane fouling and treatment efficiency were observed in a hybrid process of alumina ceramic microfiltration (MF; pore size 0.1 μm) and pure PP beads. Instead of natural organic matters and fine inorganic particles in natural water source, a quantity of humic acid (HA) and kaolin was dissolved in distilled water. The synthetic feed flowed inside the MF membrane, and the permeated water contacted the PP beads fluidized in the gap of the membrane and the acryl module case with outside UV irradiation. Periodic air back-flushing was performed to control membrane fouling during 10 s per 10 min. The membrane fouling resistance (R f ) was the maximum at 30 g/L of PP bead concentration. Finally, the maximum total permeated volume (V T ) was acquired at 5 g/L of PP beads, because flux maintained higher all through the operation. The treatment efficiency of turbidity was almost constant, independent of PP bead concentration; however, that of dissolved organic materials (DOM) showed the maximal at 50 g/L of PP beads. The R f increased as increasing feed pH from 5 to 9; however, the maximum V T was acquired at pH 6. It means that the membrane fouling could be inhibited at low acid condition. The treatment efficiency of turbidity increased a little, and that of DOM increased from 73.6 to 75.7% as increasing pH from 5 to 9.

Metal Oxide Assisted Preparation of Core-Shell Beads with Dense Metal-Organic Framework Coatings for the Enhanced Extraction of Organic Pollutants.

PubMed

Del Rio, Mateo; Palomino Cabello, Carlos; Gonzalez, Veronica; Maya, Fernando; Parra, Jose B; Cerdà, Victor; Turnes Palomino, Gemma

2016-08-08

Dense and homogeneous metal-organic framework (MOF) coatings on functional bead surfaces are easily prepared by using intermediate sacrificial metal oxide coatings containing the metal precursor of the MOF. Polystyrene (PS) beads are coated with a ZnO layer to give ZnO@PS core-shell beads. The ZnO@PS beads are reactive in the presence of 2-methylimidazole to transform part of the ZnO coating into a porous zeolitic imidazolate framework-8 (ZIF-8) external shell positioned above the internal ZnO precursor shell. The obtained ZIF-8@ZnO@PS beads can be easily packed in column format for flow-through applications, such as the solid-phase extraction of trace priority-listed environmental pollutants. The prepared material shows an excellent permeance to flow when packed as a column to give high enrichment factors, facile regeneration, and excellent reusability for the extraction of the pollutant bisphenol A. It also shows an outstanding performance for the simultaneous enrichment of mixtures of endocrine disrupting chemicals (bisphenol A, 4-tert-octylphenol and 4-n-nonylphenol), facilitating their analysis when present at very low levels (<1 μg L(-1) ) in drinking waters. For the extraction of the pollutant bisphenol A, the prepared ZIF-8@ZnO@PS beads also show a superior extraction and preconcentration capacity to that of the PS beads used as precursors and the composite materials obtained by the direct growth of ZIF-8 on the surface of the PS beads in the absence of metal oxide intermediate coatings. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of long-term elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate beads in vitro by two distinct sample collection methods.

PubMed

Tulipan, Rachel J; Phillips, Heidi; Garrett, Laura D; Dirikolu, Levent; Mitchell, Mark A

2017-05-01

OBJECTIVE To characterize long-term elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CI-CSH) beads in vitro by comparing 2 distinct sample collection methods designed to mimic 2 in vivo environments. SAMPLES 162 CI-CSH beads containing 4.6 mg of carboplatin (2.4 mg of platinum/bead). PROCEDURES For method 1, which mimicked an in vivo environment with rapid and complete fluid exchange, each of 3 plastic 10-mL conical tubes contained 3 CI-CSH beads and 5 mL of PBS solution. Eluent samples were obtained by evacuation of all fluid at 1, 2, 3, 6, 9, and 12 hours and 1, 2, 3, 6, 9, 12, 15, 18, 22, 26, and 30 days. Five milliliters of fresh PBS solution was then added to each tube. For method 2, which mimicked an in vivo environment with no fluid exchange, each of 51 tubes (ie, 3 tubes/17 sample collection times) contained 3 CI-CSH beads and 5 mL of PBS solution. Eluent samples were obtained from the assigned tubes for each time point. All samples were analyzed for platinum content by inductively coupled plasma-mass spectrometry. RESULTS Platinum was released from CI-CSH beads for 22 to 30 days. Significant differences were found in platinum concentration and percentage of platinum eluted from CI-CSH beads over time for each method. Platinum concentrations and elution percentages in method 2 samples were significantly higher than those of method 1 samples, except for the first hour measurements. CONCLUSIONS AND CLINICAL RELEVANCE Sample collection methods 1 and 2 may provide estimates of the minimum and maximum platinum release, respectively, from CI-CSH beads in vivo.

Long-term biocompatibility, imaging appearance and tissue effects associated with delivery of a novel radiopaque embolization bead for image-guided therapy.

PubMed

Sharma, Karun V; Bascal, Zainab; Kilpatrick, Hugh; Ashrafi, Koorosh; Willis, Sean L; Dreher, Matthew R; Lewis, Andrew L

2016-10-01

The objective of this study was to undertake a comprehensive long-term biocompatibility and imaging assessment of a new intrinsically radiopaque bead (LC Bead LUMI™) for use in transarterial embolization. The sterilized device and its extracts were subjected to the raft of ISO10993 biocompatibility tests that demonstrated safety with respect to cytotoxicity, mutagenicity, blood contact, irritation, sensitization, systemic toxicity and tissue reaction. Intra-arterial administration was performed in a swine model of hepatic arterial embolization in which 0.22-1 mL of sedimented bead volume was administered to the targeted lobe(s) of the liver. The beads could be visualized during the embolization procedure with fluoroscopy, DSA and single X-ray snapshot imaging modalities. CT imaging was performed before and 1 h after embolization and then again at 7, 14, 30 and 90 days. LC Bead LUMI™ could be clearly visualized in the hepatic arteries with or without administration of IV contrast and appeared more dense than soluble contrast agent. The CT density of the beads did not deteriorate during the 90 day evaluation period. The beads embolized predictably and effectively, resulting in areas devoid of contrast enhancement on CT imaging suggesting ischaemia-induced necrosis nearby the sites of occlusion. Instances of off target embolization were easily detected on imaging and confirmed pathologically. Histopathology revealed a classic foreign body response at 14 days, which resolved over time leading to fibrosis and eventual integration of the beads into the tissue, demonstrating excellent long-term tissue compatibility. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Evaluation of local toxic effects and outcomes for dogs undergoing marginal tumor excision with intralesional cisplatin-impregnated bead placement for treatment of soft tissue sarcomas: 62 cases (2009-2012).

PubMed

Bergman, Noelle S; Urie, Bridget K; Pardo, Anthony D; Newman, Rebecca G

2016-05-15

OBJECTIVE To evaluate outcomes for dogs following marginal tumor excision and intralesional placement of cisplatin-impregnated beads for the treatment of cutaneous or subcutaneous soft tissue sarcomas (STSs) and assess local toxic effects of cisplatin-impregnated beads in these patients. DESIGN Retrospective case series. ANIMALS 62 client-owned dogs. PROCEDURES Medical records were reviewed to identify dogs with STSs treated with marginal excision and intralesional placement of cisplatin-impregnated beads. Patient signalment; tumor location, type, and grade; dates of tumor resection and bead placement; number of beads placed; and concurrent treatments were recorded. Data regarding toxicosis at the bead site (up to the time of suture removal) and tumor recurrence were collected; variables of interest were evaluated for associations with these outcomes, and systemic adverse effects (if any) were recorded. RESULTS 24 of 51 (47%) evaluated dogs had toxicosis at bead placement sites (classified as mild [n = 12] or moderate [10] in most). Fifteen of 51 (29%) tumors recurred. Median disease-free interval was not reached for dogs with grade 1 and 2 STSs, whereas that for dogs with grade 3 STSs was 148 days. Disease-free survival rates of dogs with grade 1 and 2 tumors at 1, 2, and 3 years were 88%, 75%, and 64%, respectively. One dog was treated for presumptive systemic toxicosis but recovered with medical treatment. CONCLUSIONS AND CLINICAL RELEVANCE Cisplatin-impregnated beads were generally well tolerated; good results were achieved for dogs with grade 1 or 2 STSs. Prospective, controlled studies are needed to determine efficacy of this treatment for preventing recurrence of marginally excised STSs in dogs.

Parental experiences with a hospital-based bead programme for children with congenital heart disease.

PubMed

Wilson, Valerie; Chando, Shingisai

2015-02-01

To present survey findings on parental experiences with a hospital-based bead programme for children with congenital heart disease. The Heart Beads programme commenced at a paediatric hospital in Australia in 2008. Children enrolled in the programme are awarded a distinctive bead for every procedure/treatment they have while in hospital. A previous evaluation study on the programme revealed that the beads are therapeutic for the child and parents; however, due to a small sample size, the results were representative of the experiences of a small number of families who participated in the programme. This was an evaluation study which employed a nonexperimental descriptive design. Surveys were mailed to all eligible families who enrolled in the programme. Data collection occurred between July-December 2012. Questions on parental experiences with the Heart Beads programme were divided into three categories: understanding, acknowledgement and quality. Descriptive statistics were obtained and analysed. One hundred and sixty-two mothers and 136 fathers responded to the survey. Heart Beads assisted mothers (83%) and fathers (80%) with understanding their child's condition and helped them with communication (mothers 80%, fathers 58%). The majority of fathers felt that their experience was acknowledged by nursing staff (64%) and medical staff (62%), while mothers indicated a higher response from nurses (76%) compared to medical staff (67%). Overall, parents rated the programme positively; however, there was some concern that children at times missed out on beads. Understanding how mothers and fathers experience the programme differently can guide staff in their communication with parents and inform future initiatives. The Heart Beads help nurses understand how parents are experiencing care and ways in which they can provide support and acknowledgement of the parent's experience. © 2014 John Wiley & Sons Ltd.

Multi-output differential technologies

NASA Astrophysics Data System (ADS)

Bidare, Srinivas R.

1997-01-01

A differential is a very old and proven mechanical device that allows a single input to be split into two outputs having equal torque irrespective of the output speeds. A standard differential is capable of providing only two outputs from a single input. A recently patented multi-output differential technology known as `Plural-Output Differential' allows a single input to be split into many outputs. This new technology is the outcome of a systematic study of complex gear trains (Bidare 1992). The unique feature of a differential (equal torque at different speeds) can be applied to simplify the construction and operation of many complex mechanical devices that require equal torque's or forces at multiple outputs. It is now possible to design a mechanical hand with three or more fingers with equal torque. Since these finger are powered via a differential they are `mechanically intelligent'. A prototype device is operational and has been used to demonstrate the utility and flexibility of the design. In this paper we shall review two devices that utilize the new technology resulting in increased performance, robustness with reduced complexity and cost.

Microinjection--a tool to study gravitropism.

PubMed

Scherp, P; Hasenstein, K H

2003-01-01

Despite extensive studies on plant gravitropism this phenomenon is still poorly understood. The separation of gravity sensing, signal transduction and response is a common concept but especially the mechanism of gravisensing remains unclear. This paper focuses on microinjection as powerful tool to investigate gravisensing in plants. We describe the microinjection of magnetic beads in rhizoids of the green alga Chara and related subsequent manipulation of the gravisensing system. After injection, an external magnet can control the movement of the magnetic beads. We demonstrate successful injection of magnetic beads into rhizoids and describe a multitude of experiments that can be carried out to investigate gravitropism in Chara rhizoids. In addition to examining mechanical properties, bead microinjection is also useful for probing the function of the cytoskeleton by coating beads with drugs that interfere with the cytoskeleton. The injection of fluorescently labeled beads or probes may reveal the involvement of the cytoskeleton during gravistimulation and response in living cells. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Static antibiotic spacers augmented by calcium sulphate impregnated beads in revision TKA: Surgical technique and review of literature.

PubMed

Risitano, Salvatore; Sabatini, Luigi; Atzori, Francesco; Massè, Alessandro; Indelli, Pier Francesco

2018-06-01

Periprosthetic joint infection (PJI) is a serious complication in total knee arthroplasty (TKA) and represents one of the most common causes of revision. The challenge for surgeons treating an infected TKA is to quickly obtain an infection-free joint in order to re-implant, when possible, a new TKA. Recent literature confirms the role of local antibiotic-loaded beads as a strong bactericidal, allowing higher antibiotic elution when compared with antibiotic loaded spacers only. Unfortunately, classical Polymethylmethacrylate (PMMA) beads might allow bacteria adhesion, secondary development of antibiotic resistance and eventually surgical removal once antibiotics have eluted. This article describes a novel surgical technique using static, custom-made antibiotic loaded spacers augmented by calcium sulphate antibiotic-impregnated beads to improve the success rate of revision TKA in a setting of PJI. The use of calcium sulphate beads has several potential benefits, including a longer sustained local antibiotic release when compared with classical PMMA beads and, being resorbable, not requiring accessory surgical interventions.

Effect of lecithin and starch on alginate-encapsulated probiotic bacteria.

PubMed

Donthidi, A R; Tester, R F; Aidoo, K E

2010-01-01

The effect of lecithin and starch on viability of alginate encapsulated probiotics was determined at different temperatures. Probiotic organisms (1% v/v>10Log CFU ml(-1)) were encapsulated using alginate (2% w/v), gelatinized starches (2% w/v) and lecithin (0-4% w/v) and stored in sealed containers at 4, 23 and 37 degrees C (to simulate shelf storage conditions). Incorporation of lecithin improved the entrapment efficiency (p < 0.05) and the viability of encapsulated bacteria (p = 0.02). Encapsulated Lactobacillus, Bifidobacterium species and Lactococcus lactis in lecithin containing freeze-dried beads had good survival stability (above 6Log CFU ml(-1)) at 23 degrees C for 12 weeks. The bacteria in the beads showed 6Log survival by the end of 2 weeks at 37 degrees C. Encapsulated L. casei in the alginate beads containing lecithin were also more stable in the yoghurt than the beads without lecithin. SEM analysis of the beads showed an irregular surface for the beads without lecithin.

Microporous novolac-derived carbon beads/sulfur hybrid cathode for lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Choudhury, Soumyadip; Krüner, Benjamin; Massuti-Ballester, Pau; Tolosa, Aura; Prehal, Christian; Grobelsek, Ingrid; Paris, Oskar; Borchardt, Lars; Presser, Volker

2017-07-01

Novolac-derived nanoporous carbon beads were used as conductive matrix for lithium-sulfur battery cathodes. We employed a facile self-emulsifying synthesis to obtain sub-micrometer novolac-derived carbon beads with nanopores. After pyrolysis, the carbon beads showed already a specific surface area of 640 m2 g-1 which was increased to 2080 m2 g-1 after physical activation. The non-activated and the activated carbon beads represent nanoporous carbon with a medium and a high surface area, respectively. This allows us to assess the influence of the porosity on the electrochemical performance of lithium-sulfur battery cathodes. The carbon/sulfur hybrids were obtained from two different approaches of sulfur infiltration: melt-infusion of sulfur (annealing) and in situ formation of sulfur from sodium thiosulfate. The best performance (∼880 mAh gsulfur-1 at low charge rate; 5th cycle) and high performance stability (>600 mAh gsulfur-1 after 100 cycles) were found for the activated carbon beads when using melt infusion of sulfur.

Selective accumulation of harmful compounds by the DNA-inorganic hybrid-immobilized glass bead.

PubMed

Yamada, Masanori; Hamai, Akari

2009-08-11

Previously, we reported the DNA-inorganic hybrid material including double-stranded DNA by mixing the aqueous DNA solution and silane coupling reagents. Here, we immobilized the DNA-inorganic hybrid material onto the glass bead and prepared the DNA-immobilized glass bead column. The DNA-immobilized glass beads were stable in water and the amount of eluted DNA from the DNA-glass beads did not change for more than 1 week. Additionally, this DNA-immobilized column selectively accumulated the harmful compounds with the planar structure, such as dioxin- and polychlorinated biphenyl (PCB)-derivatives, and these accumulation percentages were 50-70%. Furthermore, the DNA-immobilized glass bead was recycled nine times by the application of ethanol solution and the accumulative ratio was maintained at more than 60% and did not appear to be decreasing. Therefore, these DNA-columns might have a potential for the selective removal and separation of DNA-intercalating molecules and harmful compounds with the planar structure from experimental or industrial drainages.

Skin permeation and retention of topical bead formulation containing tranexamic acid.

PubMed

Vijayakumar, Ajay; Baskaran, Rengarajan; Yoo, Bong Kyu

2017-02-01

The objective of this study is to develop a topical bead formulation of tranexamic acid (TA) which can be used concomitantly with laser treatment. The bead formulation of TA (TAB) was successfully prepared by fluidized bed drying method. Physicochemical properties of the TAB were evaluated in terms of chemical stability of TA and differential scanning calorimetry. TA in the bead was stable up to six months at 25°C and existed as amorphous state. In vitro skin permeation and in vivo skin retention of TA in the beads were significantly higher compared to a commercial product. When the bead was dissolved into distilled water and applied concomitantly with laser treatment, the amount of TA retained in the skin in the in vivo study was inversely proportional to the energy levels of laser treatment, indicating absorption into subcutaneous tissue and drainage to systemic circulation. Therefore, when laser treatment is used concomitantly with TAB, energy level should be very carefully monitored to avoid possible adverse events associated with systemic side effects of TA.

Calcium gluconate as cross-linker improves survival and shelf life of encapsulated and dried Metarhizium brunneum and Saccharomyces cerevisiae for the application as biological control agents.

PubMed

Humbert, Pascal; Przyklenk, Michael; Vemmer, Marina; Patel, Anant V

2017-02-01

Calcium chloride (CC) is the most common cross-linker for the encapsulation of biocontrol microorganisms in alginate beads. The aim of this study was to evaluate if calcium gluconate (CG) can replace CC as cross-linker and at the same time improve viability after drying and rehydration, hygroscopic properties, shelf life and nutrient supply. Hence, the biocontrol fungi Metarhizium brunneum and Saccharomyces cerevisiae were encapsulated in Ca-alginate beads supplemented with starch. Beads were dried and maximum survival was found in beads cross-linked with CG. Beads prepared with CG showed lower hygroscopic properties, but a higher shelf life for encapsulated fungi. Moreover, we demonstrated that gluconate has a nutritive effect on encapsulated fungi, leading to increased mycelium growth of M. brunneum and to enhanced CO 2 release from beads containing Saccharomyces cerevisiae. The application of CG as cross-linker will pave the way towards increasing drying survival and shelf life of various, especially drying-sensitive microbes.

Characterisation of bare and tannase-loaded calcium alginate beads by microscopic, thermogravimetric, FTIR and XRD analyses.

PubMed

Larosa, Claudio; Salerno, Marco; de Lima, Juliana Silva; Merijs Meri, Remo; da Silva, Milena Fernandes; de Carvalho, Luiz Bezerra; Converti, Attilio

2018-08-01

Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clarify juices. Copyright © 2018 Elsevier B.V. All rights reserved.

Microinjection--a tool to study gravitropism

NASA Technical Reports Server (NTRS)

Scherp, P.; Hasenstein, K. H.

2003-01-01

Despite extensive studies on plant gravitropism this phenomenon is still poorly understood. The separation of gravity sensing, signal transduction and response is a common concept but especially the mechanism of gravisensing remains unclear. This paper focuses on microinjection as powerful tool to investigate gravisensing in plants. We describe the microinjection of magnetic beads in rhizoids of the green alga Chara and related subsequent manipulation of the gravisensing system. After injection, an external magnet can control the movement of the magnetic beads. We demonstrate successful injection of magnetic beads into rhizoids and describe a multitude of experiments that can be carried out to investigate gravitropism in Chara rhizoids. In addition to examining mechanical properties, bead microinjection is also useful for probing the function of the cytoskeleton by coating beads with drugs that interfere with the cytoskeleton. The injection of fluorescently labeled beads or probes may reveal the involvement of the cytoskeleton during gravistimulation and response in living cells. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wahyuni, Wulan Tri, E-mail: wulantriws@gmail.com; Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok; Ivandini, Tribidasari A.

Biomolecule modified magnetic beads has been widely used in separation and sensing process. This study used streptavidin modified magnetic beads to immobilize biotin modified zanamivir. Biotin-streptavidin affinity facilitates immobilization of zanamivir on magnetic beads. Then interaction of zanamivir and neuraminidase was adopted as basic for enzyme detection. Detection of neuraminidase was performed at gold modified BDD using cyclic voltammetry technique. The measurement was carried out based on alteration of electrochemical signals of working electrode as neuraminidase response. The result showed that zanamivir was successfully immobilized on magnetic beads. The optimum amount of magnetic beads for zanamivir immobilization was 120 ug.more » Linear responses of neuraminidase were detected in concentration range of 0-15 mU. Detection limit (LOD) of measurement was 2.32 mU (R2 = 0.959) with precision as % RSD of 1.41%. Measurement of neuraminidase on magnetic beads could be also performed in the presence of mucin matrix. The linearity range was 0-8 mU with LOD of 0.64 mU (R2 = 0.950) and % RSD of 7.25%.« less

Viscosity of dilute suspensions of rigid bead arrays at low shear: accounting for the variation in hydrodynamic stress over the bead surfaces.

PubMed

Allison, Stuart A; Pei, Hongxia

2009-06-11

In this work, we examine the viscosity of a dilute suspension of irregularly shaped particles at low shear. A particle is modeled as a rigid array of nonoverlapping beads of variable size and geometry. Starting from a boundary element formalism, approximate account is taken of the variation in hydrodynamic stress over the surface of the individual beads. For a touching dimer of two identical beads, the predicted viscosity is lower than the exact value by 5.2%. The methodology is then applied to several other model systems including tetramers of variable conformation and linear strings of touching beads. An analysis is also carried out of the viscosity and translational diffusion of several dilute amino acids and diglycine in water. It is concluded that continuum hydrodynamic modeling with stick boundary conditions is unable to account for the experimental viscosity and diffusion data simultaneously. A model intermediate between "stick" and "slip" could possibly reconcile theory and experiment.

Disintegration of Nannochloropsis sp. cells in an improved turbine bead mill.

PubMed

Pan, Zhidong; Huang, Ying; Wang, Yanmin; Wu, Zhiwei

2017-12-01

The Nannochloropsis sp. cells in aqueous solution were disintegrated in an improved bead mill with turbine agitator. The disintegration rates of cell samples disrupted under various operating parameters (i.e., circumferential speed, bead size, disintegration time, and cell concentration) were analyzed. An experimental strategy to optimize the parameters affecting the cell disintegration process was proposed. The results show that Nannochloropsis sp. cells can be effectively disintegrated in the turbine stirred bead mill under the optimum condition (i.e., circumferential speed of 2.3m/s, concentration of 15vol.%, disintegration time of 40min and bead size of 0.3-0.4mm). The disintegration mechanism was discussed via the selection and breakage functions from population balance modelling. It is revealed that the impact and compression effects of stirring beads are more effective for the disruption of coarser fraction of cells, and the shear effect dominates the production of finer fractions of disintegrated cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spot Surface Labeling of Magnetic Microbeads and Application in Biological Force Measurements

NASA Astrophysics Data System (ADS)

Estes, Ashley; O'Brien, E. Tim; Hill, David; Superfine, Richard

2006-11-01

Biological force measurements on single molecules and macromolecular structures often use microbeads for the application of force. These techniques are often complicated by multiple attachments and nonspecific binding. In one set of experiments, we are applying a magnetic force microscope that allows us to pull on magnetic beads attached to ciliated human bronchial epithelial cells. These experiments provide a means to measure the stall force of cilia and understand how cilia propel fluids. However, because we are using beads with diameters of one and 2.8 microns, and the diameter of human airway cilia is approximately 200 nm, we cannot be assured that the bead is bound to a single cilium. To address this, we have developed a sputter coating technique to block the biotin binding capability of the streptavidin labeled bead over its entire surface except for a small spot. These beads may also have applications in other biological experiments such as DNA force experiments in which binding of a single target to an individual bead is critical.

Technology for the production of Zero Q.I pitch from coal tar

NASA Astrophysics Data System (ADS)

Karthik, K.; Kumar, K. Rajesh; Rao, C. V. Nageswara; Kumar, B. Vinod; Murty, J. V. S.

2013-06-01

Zero Quinoline Insolubles (Q.I) pitch is a special type of pitch obtained from pre-treatment of coal tar, which is converted into pitch. This is used for impregnation of electrodes for improving the strength, electrical properties and also used as a pre-cursor for Mesophase pitch for producing Mesophase pitch based carbon fibers, carbon foam, and Meso carbon micro beads. This paper discusses the technology of Q.I separation from Coal Tar by using decantation of Coal Tar mixed with Heavy Creosote Oil (HC Oil) at different temperatures. By this method we were able to produce the Zero Q.I pitch with a Q.I value of 0.1%.

Sodium bicarbonate-gelled chitosan beads as mechanically stable carriers for the covalent immobilization of enzymes.

PubMed

Wahba, Marwa I

2018-03-01

The poor mechanical stability of chitosan has long impeded its industrial utilization as an immobilization carrier. In this study, the mechanical properties of chitosan beads were greatly improved through utilizing the slow rate of the sodium bicarbonate-induced chitosan gelation and combining it with the chemical cross-linking action of glutaraldehyde (GA). The GA-treated sodium bicarbonate-gelled chitosan beads exhibited much better mechanical properties and up to 2.45-fold higher observed activity of the immobilized enzyme (β-D-galactosidase (β-gal)) when compared to the GA-treated sodium tripolyphosphate (TPP)-gelled chitosan beads. The differences between the sodium bicarbonate-gelled and the TPP-gelled chitosan beads were proven visually and also via scanning electron microscopy, elemental analysis, and differential scanning calorimetry. Moreover, the optimum pH, the optimum temperature, the apparent K m , and the apparent V max of the β-gals immobilized onto the two aforementioned types of chitosan beads were determined and compared. A reusability study was also performed. This study proved the superiority of the sodium bicarbonate-gelled chitosan beads as they retained 72.22 ± 4.57% of their initial observed activity during the 13 th reusability cycle whereas the TPP-gelled beads lost their activity during the first four reusability cycles, owing to their fragmentation. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:347-361, 2018. © 2017 American Institute of Chemical Engineers.

A prototype of injector to control and to detect the release of magnetic beads within the constraints of multibifurcation magnetic resonance navigation procedures.

PubMed

Bigot, Alexandre; Soulez, Gilles; Martel, Sylvain

2017-01-01

An injector equipped with a bead capture and a bead detection system is presented. In the context of magnetic resonance navigation (MRN), in which MRI gradients are used to steer intravascular therapeutic carriers, fast and reliable injection is essential. In this paper, we present a prototype of injector to control and to detect the release of magnetic beads. The injector relies on two distinct subsystems: (1) the capture subsystem, which creates local magnetic force to stop the flow of magnetic beads; and (2) the detection subsystem, which detects flowing beads and generates a trigger signal to start MRI gradient pulses. Both systems rely on small microcoils wound on the tubing. Five-turn microcoils show the best compromise between size and performance. Less than 5 mW of power is required to capture 0.8-mm beads moving in a flow above 5 mL min -1 or when a gradient above 200 mT m -1 is applied. The detection system is not sensitive to noise and detects every 0.8-mm bead in flow rates up to 14 mL m -1 . The prototype of injector shows performance above the requirements inherent to magnetic resonance navigation. This system is a step toward in vivo multibifurcation MRN. Magn Reson Med 77:444-452, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Microfluidic magnetic bead conveyor belt.

PubMed

van Pelt, Stijn; Frijns, Arjan; den Toonder, Jaap

2017-11-07

Magnetic beads play an important role in the miniaturization of clinical diagnostics systems. In lab-on-chip platforms, beads can be made to link to a target species and can then be used for the manipulation and detection of this species. Current bead actuation systems utilize complex on-chip coil systems that offer low field strengths and little versatility. We demonstrate a novel system based on an external rotating magnetic field and on-chip soft-magnetic structures to focus the field locally. These structures were designed and optimized using finite element simulations in order to create a number of local flux density maxima. These maxima, to which the magnetic beads are attracted, move over the chip surface in a continuous way together with the rotation of the external field, resulting in a mechanism similar to that of a conveyor belt. A prototype was fabricated using PDMS molding techniques mixed with iron powder for the magnetic structures. In the subsequent experiments, a quadrupole electromagnet was used to create the rotating external field. We observed that beads formed agglomerates that rolled over the chip surface, just above the magnetic structures. Field rotation frequencies between 0.1-50 Hz were tested resulting in magnetic bead speeds of over 1 mm s -1 for the highest frequency. With this, we have shown that our novel concept works, combining a simple design and simple operation with a powerful and versatile method for bead actuation. This makes it a promising method for further research and utilization in lab-on-chip systems.

A direct comparison of the performance of ground, beaded and silica-grafted MIPs in HPLC and turbulent flow chromatography applications.

PubMed

Fairhurst, Robert E; Chassaing, Christophe; Venn, Richard F; Mayes, Andrew G

2004-12-15

Spherical molecularly imprinted polymers (MIPs) specific to the beta-blocker propranolol have been synthesised using two different approaches and compared to traditional ground monolithic MIPs in HPLC and TFC applications. TFC is a LC technique used for rapid extraction of compounds directly from complex matrices. It can be easily coupled to HPLC and MS for automation of an extraction/analysis procedure. Spherical MIP beads were produced using a suspension polymerisation technique and silica/MIP composite beads by grafting MIP to spherical silica particles using a surface-bound initiator species. Synthesis of both beaded and silica-grafted MIPs was more practical than using the traditional grinding method and yields of spherical particles of the required size between 80 and 100% were routinely achieved. Under HPLC conditions, beaded and ground MIP materials showed a degree of chiral separation for all of the nine beta-blockers tested. The beaded MIP, however, showed much better flow properties and peak shape than the ground material. Silica-grafted MIP showed some separation in five of the drugs and a large improvement in peak shape and analysis times compared with both ground and beaded MIPs. The materials prepared were also used in extraction columns for Turbulent Flow Chromatography (TFC). Although no imprinting effect was observed under typical TFC conditions, beaded polymer materials showed promise for use as TFC extraction columns due to the good flow properties and clean extracts obtained.

Opportunities for bead-based multiplex assays in veterinary diagnostic laboratories

USDA-ARS?s Scientific Manuscript database

Bead based multiplex assays (BBMA) also referred to as Luminex, MultiAnalyte Profiling or cytometric bead array (CBA) assays, are applicable for high throughput, simultaneous detection of multiple analytes in solution (from several, up to 50-500 analytes within a single, small sample volume). Curren...

Evaluation of the Seismic Characterision of Select Engineered Nanoparticles in Saturated Glass Beads

EPA Science Inventory

A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline si...

Freeforming objects with low-binder slurry

DOEpatents

Cesarano, III, Joseph; Calvert, Paul D.

2000-01-01

In a rapid prototyping system, a part is formed by depositing a bead of slurry that has a sufficient high concentration of particles to be pseudoplastic and almost no organic binders. After deposition the bead is heated to drive off sufficient liquid to cause the bead to become dilatant.

Biochips: non-conventional strategies for biosensing elements immobilization.

PubMed

Marquette, Christophe A; Corgier, Benjamin P; Heyries, Kevin A; Blum, Loic J

2008-01-01

The present article draws a general picture of non-conventional methods for biomolecules immobilization. The technologies presented are based either on original solid supports or on innovative immobilization processes. Polydimethylsiloxane elastomer will be presented as a popular immobilization support within the biochip developer community. Electro-addressing of biomolecules at the surface of conducting biochips will appear to be an interesting alternative to immobilization processes based on surface functionalization. Finally, bead-assisted biomolecules immobilization will be presented as an open field of research for biochip developments.

Passive Nosetip Technology (PANT) Program. Volume 14. An Experimental Study to Evaluate the Irregular Nosetip Shape Regime - Data Report

DTIC Science & Technology

1974-04-01

described in Section 2.3. 2.1 MODEL FABRICATION AND MOUNTING Camphor and camphor with distributed glass particles were the materials for the low...temperature ablator shape-change models tested in Series I. The models were fabricated by molding the camphor at room temperature and high pressure (20,000 psi...distributed glass particles were produced by thoroughly mixing glass beads, having diameters of 7.5 t 1.5 mils, with the camphor gran- ules prior to

75 FR 73159 - Continental Tire North America, Inc., Receipt of Petition for Decision of Inconsequential...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-29

... is located in an area that is not more than one-fourth of the distance from the bead to the shoulder... the bead and a point one-half the distance from the bead to the shoulder of the tire, on at least one...

EMP Design Guidelines for Naval Ship Systems

DTIC Science & Technology

1975-08-22

le xc Ci .ube irret i Type FXC it LA 38 Beads 4 * 1 svj- I * 1 1 \\ Measured 3( )0 Beads V i i V 30 Bead 1 s...ATTN: R. W. Rostrom RCA Corporation Government & Commercial Systems Astro Electronics Division P. 0. Box 800 Princeton, New Jersey 08540 ATTN

Method for freeforming objects with low-binder slurry

DOEpatents

Cesarano, III, Joseph; Calvert, Paul D.

2002-01-01

In a rapid prototyping system, a part is formed by depositing a bead of slurry that has a sufficient high concentration of particles to be pseudoplastic and almost no organic binders. After deposition the bead is heated to drive off sufficient liquid to cause the bead to become dilatant.

Nutrient requirements and other factors involved in the culture of human kidney cells on microcarrier beads

NASA Technical Reports Server (NTRS)

Lewis, Marian L.; Morrison, Dennis R.

1987-01-01

The culture of human kidney cells on microcarrier beads in the Bioprocessing Laboratory at the Johnson Space Center is described. These were the first series of studies performed before and during 1983 to determine optimum conditions, including medium type, bead type and density. The composition of several medium types and the molecular weights of some common culture medium supplements and cellular proteins are included. The microgravity cell-to-bead attachment experiment performed on Space Transportation System Flight 8 is described.

Metallic Bead Detection by Using Eddy-Current Probe with SV-GMR Sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamada, S.; Chomsuwan, K.; Hagino, T.

2005-04-09

The progress of the ECT probe with micro magnetic sensor becomes possible to apply to various applications. The detection of micro metallic bead used for electric packaging has been reported in this paper. We proposed micro ECT probes with meander coil as exciter and spin-valve giant magneto-resistance (SV-GMR) as receiver. Micro metallic bead(solder ball) with the diameter of 0.25 to 0.76 mm is used as a measuring object. We discuss the detection and alignment of metallic bead by using ECT technique.

Note: A quartz cell with Pt single crystal bead electrode for electrochemical scanning tunneling microscope measurements.

PubMed

Xia, Zhigang; Wang, Jihao; Hou, Yubin; Lu, Qingyou

2014-09-01

In this paper, we provide and demonstrate a design of a unique cell with Pt single crystal bead electrode for electrochemical scanning tunneling microscope (ECSTM) measurements. The active metal Pt electrode can be protected from air contamination during the preparation process. The transparency of the cell allows the tip and bead to be aligned by direct observation. Based on this, a new and effective alignment method is introduced. The high-quality bead preparations through this new cell have been confirmed by the ECSTM images of Pt (111).

Single molecule actuation and detection on a lab-on-a-chip magnetoresistive platform

NASA Astrophysics Data System (ADS)

Chaves, R. C.; Bensimon, D.; Freitas, P. P.

2011-03-01

On-chip magnetic tweezers based on current loops were integrated with magnetoresistive sensors. Magnetic forces up to 1.0±0.3pN are produced to actuate on DNA anchored to the surface of a flow cell and labeled with micrometer-sized magnetic beads. The levitation of the beads stretches the immobilized DNA. The relative position of the magnetic beads is monitored using spin-valve sensors. A bead vertical displacement resolution of 60nm is derived for DNA molecular motor activity in a tweezer steady current regime.

Single Cell Detection with Driven Magnetic Beads

NASA Astrophysics Data System (ADS)

McNaughton, B. H.; Agayan, R. R.; Stoica, V. A.; Clarke, R.; Kopelman, R.

Shifts in the nonlinear rotational frequency of magnetic beads (microspheres) offer a new and dynamic approach for the detection of single cells. We present the first demonstration of this capability by measuring the changes in the nonlinear rotational frequency of magnetic beads driven by an external magnetic field. The presence of an Escherichia coli bacterium on the surface of a 2.0 μm magnetic bead affects the drag of the system, thus changing the nonlinear rotation rate. Measurement of this rotational frequency is straight-forward utilizing standard microscopy techniques.

“Nanofiltration” Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples

NASA Astrophysics Data System (ADS)

Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R.

2016-02-01

Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation.

Raman signatures of the modern pigment (Zn,Cd)S1-xSex and glass matrix of a red bead from Magoro Hill, an archaeological site in Limpopo Province, South Africa, recalibrate the settlement chronology

NASA Astrophysics Data System (ADS)

Prinsloo, Linda C.; Boeyens, Jan C. A.; van der Ryst, Maria M.; Webb, Geoffrey

2012-09-01

Two glass trade beads, one red and one yellow, retrieved from a secure archaeological context on Magoro Hill, an erstwhile Venda stronghold in South Africa's Limpopo Province, were analyzed with Raman and photoluminescence spectroscopy. Raman spectroscopy identified the pigment coloring the yellow bead as lead tin yellow Type II and the glass as a typical soda-lime-silica glass. Both pigments and glass type were in use over a long time span and therefore the bead cannot be used as a temporal marker. The pigment coloring the red bead, on the other hand, was identified as nano-(Zn,Cd)S1-xSex mixed crystals, a pigment that was only widely used in the early 20th century. This date casts doubt on local oral tradition that associates the brick-built structure from which the beads were recovered with Manzinzinzi, a Venda chief who, according to contemporary documentary accounts, had already passed away in the 1880s. The more recent date for the red bead resolves the apparent discord between the oral and written records, suggesting that the building was probably erected and/or occupied by one of Manzinzinzi's successors.

PHOS-Select Iron Affinity beads enrich peptides for detection of organophosphorus adducts on albumin

PubMed Central

Jiang, Wei; Dubrovskii, Yaroslav A; Podolskaya, Ekaterina P; Murashko, Ekaterina A; Babakov, Vladimir; Nachon, Florian; Masson, Patrick; Schopfer, Lawrence M; Lockridge, Oksana

2013-01-01

Albumin is covalently modified by organophosphorus toxicants (OP) on tyrosine 411, but less than 1% of albumin is modified in humans by lethal OP doses that inhibit 95% of plasma butyrylcholinesterase. A method that enriches OP-modified albumin peptides could aid analysis of low dose exposures. Soman or chlorpyrifos oxon treated human plasma was digested with pepsin. Albumin peptides were enriched by binding to Fe3+ beads at pH 11 and eluted with pH 2.6 buffer. Similarly, mouse and guinea pig albumin modified by chlorpyrifos oxon were digested with pepsin and enriched by binding to Fe3+ beads. Peptides were identified by MALDI-TOF/TOF mass spectrometry. PHOS-select Iron Affinity beads specifically enriched albumin peptides VRY411TKKVPQVST and LVRY411TKKVPQVST in a pepsin digest of human plasma. The unmodified as well as OP-modified peptides bound to the beads. The binding capacity of 500 μl beads was the pepsin digest of 2.1 μL human plasma. The limit of detection was 0.2% of OP-modified albumin peptide in 0.43 μL plasma. Enrichment of OP-modified albumin peptides by binding to Fe3+ beads is a method with potential application to diagnosis of OP pesticide and nerve agent exposure in humans, mice, and guinea pigs. PMID:24187955

Multiple pathogen biomarker detection using an encoded bead array in droplet PCR.

PubMed

Periyannan Rajeswari, Prem Kumar; Soderberg, Lovisa M; Yacoub, Alia; Leijon, Mikael; Andersson Svahn, Helene; Joensson, Haakan N

2017-08-01

We present a droplet PCR workflow for detection of multiple pathogen DNA biomarkers using fluorescent color-coded Luminex® beads. This strategy enables encoding of multiple singleplex droplet PCRs using a commercially available bead set of several hundred distinguishable fluorescence codes. This workflow provides scalability beyond the limited number offered by fluorescent detection probes such as TaqMan probes, commonly used in current multiplex droplet PCRs. The workflow was validated for three different Luminex bead sets coupled to target specific capture oligos to detect hybridization of three microorganisms infecting poultry: avian influenza, infectious laryngotracheitis virus and Campylobacter jejuni. In this assay, the target DNA was amplified with fluorescently labeled primers by PCR in parallel in monodisperse picoliter droplets, to avoid amplification bias. The color codes of the Luminex detection beads allowed concurrent and accurate classification of the different bead sets used in this assay. The hybridization assay detected target DNA of all three microorganisms with high specificity, from samples with average target concentration of a single DNA template molecule per droplet. This workflow demonstrates the possibility of increasing the droplet PCR assay detection panel to detect large numbers of targets in parallel, utilizing the scalability offered by the color-coded Luminex detection beads. Copyright © 2017. Published by Elsevier B.V.

Microparticle sampling by electrowetting-actuated droplet sweeping.

PubMed

Zhao, Yuejun; Cho, Sung Kwon

2006-01-01

This paper describes a new microparticle sampler where particles can be efficiently swept from a solid surface and sampled into a liquid medium using moving droplets actuated by the electrowetting principle. We successfully demonstrate that super hydrophilic (2 microm and 7.9 microm diameter glass beads of about 14 degrees contact angle), intermediate hydrophilic (7.5 microm diameter polystyrene beads of about 70 degrees contact angle), and super hydrophobic (7.9 microm diameter Teflon-coated glass beads and 3 microm size PTFE particles of over 110 degrees contact angles) particles on a solid surface are picked up by electrowetting-actuated moving droplets. For the glass beads as well as the polystyrene beads, the sampling efficiencies are over 93%, in particular over 98% for the 7.9 microm glass beads. For the PTFE particles, however, the sampling efficiency is measured at around 70%, relatively lower than that of the glass and polystyrene beads. This is due mainly to the non-uniformity in particle size and the particle hydrophobicity. In this case, the collected particles staying (adsorbing) on the air-to-water interface hinder the droplet from advancing. This particle sampler requires an extremely small amount of liquid volume (about 500 nanoliters) and will thus be highly compatible and easily integrated with lab-on-a-chip systems for follow-up biological/chemical analyses.

Sulindac loaded alginate beads for a mucoprotective and controlled drug release.

PubMed

Yegin, Betül Arica; Moulari, Brice; Durlu-Kandilci, N Tugba; Korkusuz, Petek; Pellequer, Yann; Lamprecht, Alf

2007-06-01

Ionotropic gelation was used to entrap sulindac into calcium alginate beads as a potential drug carrier for the oral delivery of this anti-inflammatory drug. Beads were investigated in vitro for a possible sustained drug release and their use in vivo as a gastroprotective system for sulindac. Process parameters such as the polymer concentration, polymer/drug ratio, and different needle diameter were analysed for their influences on the bead properties. Size augmented with increasing needle diameter (0.9 mm needle: 1.28 to 1.44 mm; 0.45 mm needle: 1.04 to 1.07 mm) due to changes in droplet size as well as droplet viscosity. Yields varied between 87% and 98% while sulindac encapsulation efficiencies of about 88% and 94% were slightly increasing with higher alginate concentrations. Drug release profiles exhibited a complete release for all formulations within 4 hours with a faster release for smaller beads. Sulindac loaded alginate beads led to a significant reduction of macroscopic histological damage in the stomach and duodenum in mice. Similarly, microscopic analyses of the mucosal damage demonstrated a significant mucoprotective effect of all bead formulation compared to the free drug. The present alginate formulations exhibit promising properties of a controlled release form for sulindac; meanwhile they provide a distinct tissue protection in the stomach and duodenum.

Organization of microbeads in Leidenfrost drops.

PubMed

Maquet, Laurent; Colinet, Pierre; Dorbolo, Stéphane

2014-06-21

We investigated the organization of micrometric hydrophilic beads (glass or basalt) immersed in Leidenfrost drops. Starting from a large volume of water compared to the volume of the beads, while the liquid evaporates, we observed that the grains are eventually trapped at the interface of the droplet and accumulate. At a moment, the grains entirely cover the droplet. We measured the surface area at this moment as a function of the total mass of particles inserted in the droplet. We concluded that the grains form a monolayer around the droplet assuming (i) that the packing of the beads at the surface is a random close packing and (ii) that the initial surface of the drop is larger than the maximum surface that the beads can cover. Regarding the evaporation dynamics, the beads are found to reduce the evaporation rate of the drop. The slowdown of the evaporation is interpreted as being the consequence of the dewetting of the particles located at the droplet interface which makes the effective surface of evaporation smaller. As a matter of fact, contact angles of the beads with the water deduced from the evaporation rates are consistent with contact angles of beads directly measured at a flat air-water interface of water in a container.

Preparation and testing of a tetra-amine copper(II) chitosan bead system for enhanced phosphate remediation.

PubMed

Kumar, Ilango Aswin; Viswanathan, Natrayasamy

2018-03-01

A tetra-amine copper(II) chitosan bead system (TAC@CS composite beads) was developed by grafting tetra-amine copper(II) (TAC) with chitosan (CS) and utilized for phosphate removal. The prepared TAC@CS composite beads possess enhanced phosphate sorption capacity (SC) of 41.42 ± 0.071 mg/g than copper grafted chitosan (Cu@CS) composite, TAC and chitosan which were found to be 37.01 ± 0.803, 33.20 ± 0.650 and 7.24 ± 0.059 mg/g respectively. In batch mode, various adsorption influencing parameters like contact time, initial phosphate concentration, solution pH, co-anions and temperature were optimized for maximum phosphate sorption. The prepared adsorbents were characterized by FTIR, XRD, UV-Visible, SEM and EDAX analysis. The adsorption isotherms and thermodynamic parameters of the adsorbent were studied. The feasible phosphate uptake mechanism of TAC@CS biocomposite beads was reported. The reusability studies of TAC@CS composite beads were carried out using NaOH as elutant. The suitability of TAC@CS composite beads at field conditions was tested with phosphate contaminated field water samples collected from nearby areas of Dindigul district. Copyright © 2017 Elsevier Ltd. All rights reserved.

"Nanofiltration" Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples.

PubMed

Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R

2016-02-15

Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation.

Structuring and calorie control of bakery products by templating batter with ultra melt-resistant food-grade hydrogel beads.

PubMed

Thompson, Benjamin R; Horozov, Tommy S; Stoyanov, Simeon D; Paunov, Vesselin N

2017-08-01

We report the use of a temperature insensitive, food-grade hydrogel to reduce the caloric density of pancakes that were prepared at temperatures much higher than the boiling point of water. This cheap, facile method utilises a mixed agar-methylcellulose hydrogel, which was blended to produce a slurry of hydrogel microbeads. The pancake batter was mixed with a controlled volume percentage of slurry of hydrogel beads and cooked. From bomb calorimetry experiments, the composites were found to have a reduced caloric density that reflects the volume percentage of hydrogel beads mixed with the batter. Using this procedure, we were able to reduce the caloric density of pancakes by up to 23 ± 3% when the volume percentage of hydrogel beads initially used was 25%. The method is not limited to pancakes and could potentially be applied to various other food products. The structure and morphology of the freeze-dried pancakes and pancake-hydrogel composites were investigated and pores of a similar size to the hydrogel beads were found, confirming that the gel beads maintained their structure during the cooking process. There is scope for further development of this method by the encapsulation of nutritionally beneficial or flavour enhancing ingredients within the hydrogel beads.

Graphene oxide/alginate beads as adsorbents: Influence of the load and the drying method on their physicochemical-mechanical properties and adsorptive performance.

PubMed

Platero, Emiliano; Fernandez, Maria Emilia; Bonelli, Pablo Ricardo; Cukierman, Ana Lea

2017-04-01

Graphene oxide/alginate beads were prepared from lab-synthesized graphene oxide, varying its content within the beads (0.05, 0.125, and 0.25wt.%). Ethanol-drying and lyophilization were compared as drying methods to obtain suitable adsorbents which were later tested to the removal of a model organic molecule (methylene blue). The morphological and textural properties of all the beads were characterized by scanning electron microscopy and N 2 adsorption/desorption isotherms at -196°C, respectively. Limited porosity was obtained for all cases (S BET <60m 2 /g). Uniaxial compression tests were performed to assess the mechanical properties of the beads. Ethanol-dried ones exhibited higher Young's elasticity modulus (E=192kPa) than the lyophilized samples (twice at 0.25wt.% graphene oxide loading), which disclosed breakage points at lower deformation percentages. Adsorption experiments were conducted and dye adsorption isotherms were obtained for the beads with the best removal performance. The experimental data were better fitted by the Langmuir model. The highest maximum adsorption capacity (4.25mmol/g) was obtained for the lyophilized beads with the highest graphene oxide content. Mechanical properties were found to be affected also by the dye adsorption. Copyright © 2016 Elsevier Inc. All rights reserved.

Blood Compatibility of Sulfonated Cladophora Nanocellulose Beads.

PubMed

Rocha, Igor; Lindh, Jonas; Hong, Jaan; Strømme, Maria; Mihranyan, Albert; Ferraz, Natalia

2018-03-07

Sulfonated cellulose beads were prepared by oxidation of Cladophora nanocellulose to 2,3-dialdehyde cellulose followed by sulfonation using bisulfite. The physicochemical properties of the sulfonated beads, i.e., high surface area, high degree of oxidation, spherical shape, and the possibility of tailoring the porosity, make them interesting candidates for the development of immunosorbent platforms, including their application in extracorporeal blood treatments. A desired property for materials used in such applications is blood compatibility; therefore in the present work, we investigate the hemocompatibility of the sulfonated cellulose beads using an in vitro whole blood model. Complement system activation (C3a and sC5b-9 levels), coagulation activation (thrombin-antithrombin (TAT) levels) and hemolysis were evaluated after whole blood contact with the sulfonated beads and the results were compared with the values obtained with the unmodified Cladophora nanocellulose. Results showed that neither of the cellulosic materials presented hemolytic activity. A marked decrease in TAT levels was observed after blood contact with the sulfonated beads, compared with Cladophora nanocellulose. However, the chemical modification did not promote an improvement in Cladophora nanocellulose hemocompatibility in terms of complement system activation. Even though the sulfonated beads presented a significant reduction in pro-coagulant activity compared with the unmodified material, further modification strategies need to be investigated to control the complement activation by the cellulosic materials.

Adsorption of ochratoxin A from grape juice by yeast cells immobilised in calcium alginate beads.

PubMed

Farbo, Maria Grazia; Urgeghe, Pietro Paolo; Fiori, Stefano; Marceddu, Salvatore; Jaoua, Samir; Migheli, Quirico

2016-01-18

Grape juice can be easily contaminated with ochratoxin A (OTA), one of the known mycotoxins with the greatest public health significance. Among the different approaches to decontaminate juice from this mycotoxin, microbiological methods proved efficient, inexpensive and safe, particularly the use of yeast or yeast products. To ascertain whether immobilisation of the yeast biomass would lead to successful decontamination, alginate beads encapsulating Candida intermedia yeast cells were used in our experiments to evaluate their OTA-biosorption efficacy. Magnetic calcium alginate beads were also prepared by adding magnetite in the formulation to allow fast removal from the aqueous solution with a magnet. Calcium alginate beads were added to commercial grape juice spiked with 20 μg/kg OTA and after 48 h of incubation a significant reduction (>80%), of the total OTA content was achieved, while in the subsequent phases (72-120 h) OTA was slowly released into the grape juice by alginate beads. Biosorption properties of alginate-yeast beads were tested in a prototype bioreactor consisting in a glass chromatography column packed with beads, where juice amended with OTA was slowly flowed downstream. The adoption of an interconnected scaled-up bioreactor as an efficient and safe tool to remove traces of OTA from liquid matrices is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

“Nanofiltration” Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples

PubMed Central

Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R.

2016-01-01

Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation. PMID:26876979

Alginate-caseinate composites: Molecular interactions and characterization of cross-linked beads for the delivery of anticandidals.

PubMed

Khlibsuwan, Rapee; Khunkitti, Watcharee; Pongjanyakul, Thaned

2018-04-19

Polysaccharide-protein composites offer potential utility for the delivery of drugs. The objectives of this work were to investigate the molecular interactions between sodium alginate (SA) and sodium caseinate (SC) in dispersions and films and to characterize calcium alginate (CA) beads mixed with SC for the delivery of fluconazole (FZ) and clotrimazole (CZ). The results demonstrated that SA could interact with SC, which caused a viscosity synergism in the dispersions. Hydrogen bonding between the carboxyl or hydroxyl groups of SA and the amide groups of SC led to the formation of soluble complexes that could reinforce the CA beads prepared by calcium cross-linking. The SC-CA beads provided higher drug entrapment efficiency, lower water uptake and erosion, and slower drug release than for the CA beads. The loaded FZ was an amorphous form, but CZ crystals were embedded in the bead matrix due to the low water solubility of this drug. However, SC micellization could enhance the water solubility and efficacy of CZ against Candida albicans. This finding indicates that SA can interact with SC via hydrogen bonding to form complexes and that the anticandidal-loaded SC-CA beads can be used as drug delivery systems and drug reservoirs in tablets for oral candidiasis. Copyright © 2018 Elsevier B.V. All rights reserved.

A new dimension in retrograde flow: centripetal movement of engulfed particles.

PubMed Central

Caspi, A; Yeger, O; Grosheva, I; Bershadsky, A D; Elbaum, M

2001-01-01

Centripetal motion of surface-adherent particles is a classic experimental system for studying surface dynamics on a eukaryotic cell. To investigate bead migration over the entire cell surface, we have developed an experimental assay using multinuclear giant fibroblasts, which provide expanded length scales and an unambiguous frame of reference. Beads coated by adhesion ligands concanavalin A or fibronectin are placed in specific locations on the cell using optical tweezers, and their subsequent motion is tracked over time. The adhesion, as well as velocity and directionality of their movement, expose distinct regions of the cytoplasm and membrane. Beads placed on the peripheral lamella initiate centripetal motion, whereas beads placed on the central part of the cell attach to a stationary cortex and do not move. Careful examination by complementary three-dimensional methods shows that the motion of a bead placed on the cell periphery takes place after engulfment into the cytoplasm, whereas stationary beads, placed near the cell center, are not engulfed. These results demonstrate that centripetal motion of adhering particles may occur inside as well as outside the cell. Inhibition of actomyosin activity is used to explore requirements for engulfment and aspects of the bead movement. Centripetal movement of adherent particles seems to depend on mechanisms distinct from those driving overall cell contractility. PMID:11566772

Dielectrophoretic spectroscopy using a microscopic electrode array

NASA Astrophysics Data System (ADS)

Kirmani, Syed Abdul Mannan; Gudagunti, Fleming Dackson; Velmanickam, Logeeshan; Nawarathna, Dharmakeerthi; Lima, Ivan T.

2017-02-01

Dielectrophoresis (DEP) is a commonly used technique in biomedical engineering to manipulate biomolecules. DEP is defined as the force acting on dielectric particles when they are exposed to non-uniform electric fields. DEP effect can be divided in three categories: positive (dielectric particles are attracted to the electrodes), negative, and zero force DEP. The cross-over frequency is the frequency in which the DEP force is equal to zero. The cross-over frequency depends on the conductivity and the permittivity of the particles and of the suspended medium. The DEP cross-over frequency has been utilized in detecting/quantifying biomolecules. A manual procedure is commonly used to estimate the cross-over frequency of biomolecules. Therefore, the accuracy of this detection method is significantly limited. To address this issue, we designed and tested an automated procedure to carry out DEP spectroscopy in dielectric particles dissolved in a biological buffer solution. Our method efficiently measures the effect of the DEP force through a live video feed from the microscope camera and performs real-time image processing. It records the change in the fluorescence emission as the system automatically scans the electric frequency of the function generator over a specified time interval. We demonstrated the effectiveness of the method by extracting the crossover frequencies and the DEP spectrum of polystyrene beads with blue color dye (1000 nm diameter) and green fluorescent polystyrene beads with 500 nm diameter using this procedure. This approach can lead to the development of a biosensor with significantly higher sensitivity than existing detection methods.

Role of special cross-links in structure formation of bacterial DNA polymer

NASA Astrophysics Data System (ADS)

Agarwal, Tejal; Manjunath, G. P.; Habib, Farhat; Lakshmi Vaddavalli, Pavana; Chatterji, Apratim

2018-01-01

Using data from contact maps of the DNA-polymer of Escherichia coli (E. Coli) (at kilobase pair resolution) as an input to our model, we introduce cross-links between monomers in a bead-spring model of a ring polymer at very specific points along the chain. Via suitable Monte Carlo simulations, we show that the presence of these cross-links leads to a particular organization of the chain at large (micron) length scales of the DNA. We also investigate the structure of a ring polymer with an equal number of cross-links at random positions along the chain. We find that though the polymer does get organized at the large length scales, the nature of the organization is quite different from the organization observed with cross-links at specific biologically determined positions. We used the contact map of E. Coli bacteria which has around 4.6 million base pairs in a single circular chromosome. In our coarse-grained flexible ring polymer model, we used 4642 monomer beads and observed that around 80 cross-links are enough to induce the large-scale organization of the molecule accounting for statistical fluctuations caused by thermal energy. The length of a DNA chain even of a simple bacterial cell such as E. Coli is much longer than typical proteins, hence we avoided methods used to tackle protein folding problems. We define new suitable quantities to identify the large scale structure of a polymer chain with a few cross-links.

Highly parallel single-molecule amplification approach based on agarose droplet polymerase chain reaction for efficient and cost-effective aptamer selection.

PubMed

Zhang, Wei Yun; Zhang, Wenhua; Liu, Zhiyuan; Li, Cong; Zhu, Zhi; Yang, Chaoyong James

2012-01-03

We have developed a novel method for efficiently screening affinity ligands (aptamers) from a complex single-stranded DNA (ssDNA) library by employing single-molecule emulsion polymerase chain reaction (PCR) based on the agarose droplet microfluidic technology. In a typical systematic evolution of ligands by exponential enrichment (SELEX) process, the enriched library is sequenced first, and tens to hundreds of aptamer candidates are analyzed via a bioinformatic approach. Possible candidates are then chemically synthesized, and their binding affinities are measured individually. Such a process is time-consuming, labor-intensive, inefficient, and expensive. To address these problems, we have developed a highly efficient single-molecule approach for aptamer screening using our agarose droplet microfluidic technology. Statistically diluted ssDNA of the pre-enriched library evolved through conventional SELEX against cancer biomarker Shp2 protein was encapsulated into individual uniform agarose droplets for droplet PCR to generate clonal agarose beads. The binding capacity of amplified ssDNA from each clonal bead was then screened via high-throughput fluorescence cytometry. DNA clones with high binding capacity and low K(d) were chosen as the aptamer and can be directly used for downstream biomedical applications. We have identified an ssDNA aptamer that selectively recognizes Shp2 with a K(d) of 24.9 nM. Compared to a conventional sequencing-chemical synthesis-screening work flow, our approach avoids large-scale DNA sequencing and expensive, time-consuming DNA synthesis of large populations of DNA candidates. The agarose droplet microfluidic approach is thus highly efficient and cost-effective for molecular evolution approaches and will find wide application in molecular evolution technologies, including mRNA display, phage display, and so on. © 2011 American Chemical Society

Development, Characterisation and Application of Monoclonal Antibodies for the Detection and Quantification of Infectious Salmon Anaemia Virus in Plasma Samples Using Luminex Bead Array Technology.

PubMed

Hoare, R; Thompson, K D; Herath, T; Collet, B; Bron, J E; Adams, A

2016-01-01

Infectious salmon anaemia virus (ISAV) is an orthomyxovirus that has had a significant economic impact on Atlantic salmon farming in Europe, North America and Chile. Monoclonal antibodies (mAbs) were developed against Segment 3 (encoding the viral nucleoprotein, NP) of the virus. Six of the mAbs were shown to be specific to ISAV and recognised all isolates from Scotland, Norway and Canada. They reacted with ISAV in enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody technique (IFAT) and western blotting. They were also used to develop a novel detection method based on Luminex (Bio-Plex) bead-based flow cytometric technology for the detection of ISAV in the plasma of Atlantic salmon (Salmo salar L.) smolts experimentally infected with ISAV. Fish were challenged by intraperitoneal (i.p.) injection of virus at 50% Tissue Culture Infective Dose (TCID50) = 2.8 x106 per animal. Virus present in plasma of infected fish, collected at 0, 4, 8, 12, 16, 21 and 28 days post infection using a non-lethal sampling method (n = 12 at each time point), was quantified using the optimised Bio-Plex assay. The results obtained with this assay were compared with absolute quantification of the virus by RT-qPCR using SYBR Green I and TaqMan chemistries. The Bio-Plex assay developed using the NP mAbs appears to be a rapid, sensitive method for detecting and quantifying ISAV in small volumes of fish plasma and has the potential to be multiplexed for the detection of other fish pathogens (e.g. during co-infections). To our knowledge this is the first report of the use of Luminex (Bio-Plex) technology for the detection of a fish pathogen.

Soluble Protein Analysis using a Compact Bench-top Flow Cytometer

NASA Technical Reports Server (NTRS)

Pappas, Dimitri; Kao, Shib-Hsin; Cyr, Johnathan

2004-01-01

Future space exploration missions will require analytical technology capable of providing both autonomous medical care to the crew and investigative capabilities to researchers. While several promising candidate technologies exist for further development, flow cytometry is an attractive technology as it offers both crew health (blood cell count, leukocyte differential, etc.) and a wide array of biochemistry and immunology assays. research settings, the application of this technique to soluble protein analysis is also possible. Proteomic beads using fluorescent dyes for optical encoding were used to monitor six cytokines simultaneously in cell medium of cell cultures in stationary and rotating cell culture systems. The results of this work demonstrate that a compact flow cytometer, such as a system proposed for space flight, can detect a variety of soluble proteins for crew health and biotechnology experiments during long-term missions.

Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

NASA Astrophysics Data System (ADS)

Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. C.

2015-01-01

Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a circum-Arctic survey of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium to high ground-ice content permafrost in moderately sloping terrain. In one Arctic coastal plain watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. The comparisons of one beaded channel using repeat photography between 1948 and 2013 indicate a relatively stable landform, and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in riparian zones, effectively insulate channel ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 °C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features that range from 0.7 to 1.6 m. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains cold-water habitats. Snowmelt-generated peak flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.01 to 0.1 m s-1, yet channel runs still move water rapidly between pools. The repeating spatial pattern associated with beaded stream morphology and hydrological dynamics may provide abundant and optimal foraging habitat for fish. Beaded streams may create important ecosystem functions and habitat in many permafrost landscapes and their distribution and dynamics are only beginning to be recognized in Arctic research.

Beaded streams of Arctic permafrost landscapes

NASA Astrophysics Data System (ADS)

Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. C.

2014-07-01

Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic inventory of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high-ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate relatively stable form and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in stream gulches effectively insulates river ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 °C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools stratify thermally, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m s-1, yet channel runs still move water rapidly between pools. This repeating spatial pattern associated with beaded stream morphology and hydrological dynamics may provide abundant and optimal foraging habitat for fish. Thus, beaded streams may create important ecosystem functions and habitat in many permafrost landscapes and their distribution and dynamics are only beginning to be recognized in Arctic research.

Processes Leading to Beaded Channels Formation in Central Yakutia

NASA Astrophysics Data System (ADS)

Tarbeeva, A. M.; Lebedeva, L.; Efremov, V. S.; Krylenko, I. V.; Surkov, V. V.

2017-12-01

Beaded channels, consisting of deepened and widened pools and connecting narrow runs, are common fluvial forms in permafrost regions. Recent studies have shown that beaded channels are very important for connecting alluvial rivers with headwater lakes allowing fish passage and foraging habitats, as well as regulating river runoff. Beaded channels are known as typical thermokarst landforms; however, there is no evidence of their origin and formative processes. Geomorphological analyzes of beaded channels have been completed in several permafrost regions including field observations of Shestakovka River in Central Yakutia. The study aims to recognize the modern exogenic processes and formative mechanisms of beaded river channels. We show that beaded channel of Shestakovka River form in the perennially frozen sand with low ice content, leading us to hypothesize that thermokarst is not the main process of formation. Due to the significant volume of water, the pools don't freeze over entirely during winters, even under harsh climatic conditions. As a result, lenses of pressurized water remain under surface ice underlain by perennially thawed sediments. The presence of thawed sediments under the pools and frozen sediments under the runs leads to uneven thermoerosion of the riverbed during floods, providing the beaded form of the channel. In addition, freezing of pools during winter leads to pressure increasing under ice cover and formation of ice mounds, which crack several times during winter leading to disturbance of riverbanks. Many 1st to 3rd order streams have a specific transitional meandering-to-beaded form resembling the shape of unconfined meandering rivers, but consisting of pools and runs. However, such channels exhibit no evidences of present-day erosion of concave banks and sediment accumulation at the convex banks as typically being observed in normally meandering rivers. Such forms of channels indicates that their formation occurred by the greater channel-forming flow discharges in the past. Transition to the beaded channel planform took place only later, presumably as a result of climate changes. Reduction of water runoff and freezing over of taliks leaded to activation of cryogenic processes (thermokarst, uneven thermoerosion, disturbance of riverbanks during the cracking of ice mounds).

Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

USGS Publications Warehouse

Arp, Christopher D.; Whitman, Matthew S.; Jones, Benjamin M.; Grosse, Guido; Gaglioti, Benjamin V.; Heim, Kurt C.

2015-01-01

Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic survey of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high- ground ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate a relatively stable landform and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in riparian zones effectively insulates channel ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2°C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m/s, yet channel runs still move water rapidly between pools. The repeating spatial pattern associated with beaded stream morphology and hydrological dynamics may provide abundant and optimal foraging habitat for fish. Thus, beaded streams may create important ecosystem functions and habitat in many permafrost landscapes and their distribution and dynamics are only beginning to be recognized in Arctic research.

Automated electrotransformation of Escherichia coli on a digital microfluidic platform using bioactivated magnetic beads.

PubMed

Moore, J A; Nemat-Gorgani, M; Madison, A C; Sandahl, M A; Punnamaraju, S; Eckhardt, A E; Pollack, M G; Vigneault, F; Church, G M; Fair, R B; Horowitz, M A; Griffin, P B

2017-01-01

This paper reports on the use of a digital microfluidic platform to perform multiplex automated genetic engineering (MAGE) cycles on droplets containing Escherichia coli cells. Bioactivated magnetic beads were employed for cell binding, washing, and media exchange in the preparation of electrocompetent cells in the electrowetting-on-dieletric (EWoD) platform. On-cartridge electroporation was used to deliver oligonucleotides into the cells. In addition to the optimization of a magnetic bead-based benchtop protocol for generating and transforming electrocompetent E. coli cells, we report on the implementation of this protocol in a fully automated digital microfluidic platform. Bead-based media exchange and electroporation pulse conditions were optimized on benchtop for transformation frequency to provide initial parameters for microfluidic device trials. Benchtop experiments comparing electrotransformation of free and bead-bound cells are presented. Our results suggest that dielectric shielding intrinsic to bead-bound cells significantly reduces electroporation field exposure efficiency. However, high transformation frequency can be maintained in the presence of magnetic beads through the application of more intense electroporation pulses. As a proof of concept, MAGE cycles were successfully performed on a commercial EWoD cartridge using variations of the optimal magnetic bead-based preparation procedure and pulse conditions determined by the benchtop results. Transformation frequencies up to 22% were achieved on benchtop; this frequency was matched within 1% (21%) by MAGE cycles on the microfluidic device. However, typical frequencies on the device remain lower, averaging 9% with a standard deviation of 9%. The presented results demonstrate the potential of digital microfluidics to perform complex and automated genetic engineering protocols.

Automated electrotransformation of Escherichia coli on a digital microfluidic platform using bioactivated magnetic beads

PubMed Central

Moore, J. A.; Nemat-Gorgani, M.; Madison, A. C.; Punnamaraju, S.; Eckhardt, A. E.; Pollack, M. G.; Church, G. M.; Fair, R. B.; Horowitz, M. A.; Griffin, P. B.

2017-01-01

This paper reports on the use of a digital microfluidic platform to perform multiplex automated genetic engineering (MAGE) cycles on droplets containing Escherichia coli cells. Bioactivated magnetic beads were employed for cell binding, washing, and media exchange in the preparation of electrocompetent cells in the electrowetting-on-dieletric (EWoD) platform. On-cartridge electroporation was used to deliver oligonucleotides into the cells. In addition to the optimization of a magnetic bead-based benchtop protocol for generating and transforming electrocompetent E. coli cells, we report on the implementation of this protocol in a fully automated digital microfluidic platform. Bead-based media exchange and electroporation pulse conditions were optimized on benchtop for transformation frequency to provide initial parameters for microfluidic device trials. Benchtop experiments comparing electrotransformation of free and bead-bound cells are presented. Our results suggest that dielectric shielding intrinsic to bead-bound cells significantly reduces electroporation field exposure efficiency. However, high transformation frequency can be maintained in the presence of magnetic beads through the application of more intense electroporation pulses. As a proof of concept, MAGE cycles were successfully performed on a commercial EWoD cartridge using variations of the optimal magnetic bead-based preparation procedure and pulse conditions determined by the benchtop results. Transformation frequencies up to 22% were achieved on benchtop; this frequency was matched within 1% (21%) by MAGE cycles on the microfluidic device. However, typical frequencies on the device remain lower, averaging 9% with a standard deviation of 9%. The presented results demonstrate the potential of digital microfluidics to perform complex and automated genetic engineering protocols. PMID:28191268

Elemental analysis of bead samples using a laser-induced plasma at low pressure

NASA Astrophysics Data System (ADS)

Lie, Tjung Jie; Kurniawan, Koo Hendrik; Kurniawan, Davy P.; Pardede, Marincan; Suliyanti, Maria Margaretha; Khumaeni, Ali; Natiq, Shouny A.; Abdulmadjid, Syahrun Nur; Lee, Yong Inn; Kagawa, Kiichiro; Idris, Nasrullah; Tjia, May On

2006-01-01

An Nd:YAG laser (1064 nm, 8 ns, 30 mJ) was focused on various types of fresh, fossilized white coral and giant shell samples, including samples of imitation shell and marble. Such samples are extremely important as material for preparing prayer beads that are extensively used in the Buddhist faith. The aim of this research was to develop a non-destructive method to distinguish original beads from their imitations by means of spectral measurements of the carbon, hydrogen, sodium and magnesium emission intensities and by measuring the hardness of the sample using the ratio between Ca (II) 396.8 nm and Ca (I) 422.6 nm. Based on these measurements, original fresh coral beads can be distinguished from any imitation made from hard wood. The same technique was also effective in distinguishing beads made of shell from its imitation. A spectral analysis of bead was also performed on a fossilized white coral sample and the result can be used to distinguish to some extent the fossilized white coral beads from any imitation made from marble. It was also found that the plasma plume should be generated at low ambient pressure to significantly improve the hydrogen and carbon emission intensity and also to avoid energy loss inside the crater during laser irradiation at atmospheric pressure. The results of this study confirm that operating the laser-induced plasma spectroscopy at reduced ambient pressure offers distinct advantage for bead analysis over the conventional laser-induced breakdown spectroscopy (LIBS) technique operated at atmospheric pressure.

Use of antibiotic beads to salvage infected breast implants.

PubMed

Sherif, Rami D; Ingargiola, Michael; Sanati-Mehrizy, Paymon; Torina, Philip J; Harmaty, Marco A

2017-10-01

When an implant becomes infected, implant salvage is often performed where the implant is removed, capsulectomy is performed, and a new implant is inserted. The patient is discharged with a PICC line and 6-8 weeks of intravenous (IV) antibiotics. This method has variable success and subjects the patient to long-term systemic antibiotics. In the 1960s, the use of antibiotic-impregnated beads for the treatment of chronic osteomyelitis was described. These beads deliver antibiotic directly to the site of the infection, thereby eliminating the complications of systemic IV antibiotics. This study aimed to present a case series illustrating the use of STIMULAN calcium sulfate beads loaded with vancomycin and tobramycin to increase the rate of salvage of the infected implant and forgo IV antibiotics. A retrospective analysis was performed of patients who were treated at Mount Sinai Hospital for implant infection with salvage and antibiotic beads. Twelve patients were identified, 10 of whom had breast cancer. Comorbidities included hypertension, smoking, and immunocompromised status. Infections were noted anywhere from 5 days to 8 years postoperatively. Salvage was successful in 9 out of the 12 infected implants using antibiotic bead therapy without home IV antibiotics. The use of antibiotic beads is promising for salvaging infected breast implants without IV antibiotics. Seventy-five percent of the implants were successfully salvaged. Of the three patients who had unsalvageable implants, one was infected with antibiotic-resistant Rhodococcus that was refractory to bead therapy and one was noncompliant with postoperative instructions. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Comparison of different immobilized systems in the removal of peanut allergens from peanut extracts.

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine which of the magnetic-bead systems (Ca2+, Fe3+, caffeic acid, hydrophobic) would bind and separate peanut allergens from other proteins in a peanut extract more efficiently. Commercial Ca2+ and hydrophobic magnetic beads, and caffeic-beads (prepared by at...

Synthesis, characterization and applications of maghemite beads functionalized with rabbit antibodies.

PubMed

Rodriguez, A F R; Rocha, C O; Piazza, R D; Dos Santos, C C; Morales, M A; Faria, F S E D V; Iqbal, M Zubair; Barbosa, L; Chaves, Y O; Mariuba, L A; Jafelicci, M; Marques, R F C

2018-06-12

Magnetic nanoparticles (NPs) have attracted great attention owing to their applications in the biomedical field. In the present work, maghemite (γFe 2 O 3 ) NPs of 6.5 nm were prepared using a sonochemical method and used to prepare magnetic beads through silanization with 3-aminopropyltrimethoxysilane (APTS). Subsequently, amino groups in the resulting APTS-γFe 2 O 3 beads were converted to carboxylic acid (CARB-γFe 2 O 3 ) through the succinic anhydride reaction, as confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and dynamic light scattering (DLS) measurements. The size of these beads was measured as 12 nm and their hydrodynamic diameter as 490 nm, using TEM analysis and DLS, respectively. The CARB-γFe 2 O 3 beads were further functionalized by immobilizing rabbit antibodies on their surfaces; the immobilization was confirmed by flow cytometry and ionic strength. The samples were further characterized by Mössbauer spectroscopy and DC magnetization measurements. Studies on magnetic relaxivities showed that magnetic beads present great potential for application in MR imaging.

Application of a rotating impeller anode in a bioelectrochemical anaerobic digestion reactor for methane production from high-strength food waste.

PubMed

Park, Jungyu; Lee, Beom; Shin, Wonbeom; Jo, Sangyeol; Jun, Hangbae

2018-07-01

In this study, a practical bioelectrochemical anaerobic digestion (BEAD) reactor equipped with a rotating STS304 impeller was tested to verify its methane production performance. Methane production in the BEAD reactor was possible without accumulation of volatile fatty acids (VFAs) and decreases in pH at high organic loading rates (OLRs) up to 6 kg-COD/m 3 ·d (COD: chemical oxygen demand). Methane production in a BEAD-O (open circuit) reactor was inhibited at OLRs above 4 kg-COD/m 3 ·d; however, the performance could be recovered bioelectrochemically by supplying voltage. The population density of hydrogenotrophic methanogens increased to 73.3% in the BEAD-C (closed circuit) reactor, even at high OLRs, through the removal of VFAs and conversion of hydrogen to methane. The energy efficiency in the BEAD-C reactor was 85.6%, indicating that the commercialization of BEAD reactors equipped with rotating STS304 impeller electrodes is possible. Copyright © 2018 Elsevier Ltd. All rights reserved.

In-situ preparation of NaA zeolite/chitosan porous hybrid beads for removal of ammonium from aqueous solution.

PubMed

Yang, Kai; Zhang, Xiang; Chao, Cong; Zhang, Bing; Liu, Jindun

2014-07-17

Inorganic/organic hybrid materials play important roles in removal of contaminants from wastewater. Herein, we used the natural materials of halloysite and chitosan to prepare a new adsorbent of NaA zeolite/chitosan porous hybrid beads by in-situ hydrothermal synthesis method. SEM indicated that the porous hybrid beads were composed of 6-8 μm sized cubic NaA zeolite particles congregated together with chitosan. The adsorption behavior of NH4(+) from aqueous solution onto hybrid beads was investigated at different conditions. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 47.62 mg/g at 298 K was achieved according to Langmuir model. The regenerated or reused experiments indicated that the adsorption capacity of the hybrid beads could maintain in 90% above after 10 successive adsorption-desorption cycles. The high adsorption and reusable ability implied potential application of the hybrid beads for removing NH4(+) pollutants from wastewater. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multi-parameter analysis using photovoltaic cell-based optofluidic cytometer

PubMed Central

Yan, Chien-Shun; Wang, Yao-Nan

2016-01-01

A multi-parameter optofluidic cytometer based on two low-cost commercial photovoltaic cells and an avalanche photodetector is proposed. The optofluidic cytometer is fabricated on a polydimethylsiloxane (PDMS) substrate and is capable of detecting side scattered (SSC), extinction (EXT) and fluorescence (FL) signals simultaneously using a free-space light transmission technique without the need for on-chip optical waveguides. The feasibility of the proposed device is demonstrated by detecting fluorescent-labeled polystyrene beads with sizes of 3 μm, 5 μm and 10 μm, respectively, and label-free beads with a size of 7.26 μm. The detection experiments are performed using both single-bead population samples and mixed-bead population samples. The detection results obtained using the SSC/EXT, EXT/FL and SSC/FL signals are compared with those obtained using a commercial flow cytometer. It is shown that the optofluidic cytometer achieves a high detection accuracy for both single-bead population samples and mixed-bead population samples. Consequently, the proposed device provides a versatile, straightforward and low-cost solution for a wide variety of point-of-care (PoC) cytometry applications. PMID:27699122

Facile preparation of antibacterial chitosan/graphene oxide-Ag bio-nanocomposite hydrogel beads for controlled release of doxorubicin.

PubMed

Rasoulzadehzali, Monireh; Namazi, Hassan

2018-04-27

The present project describes the facile preparation of novel pH-sensitive bio-nanocomposite hydrogel beads based on chitosan (CH) and GO-Ag nanohybrid particles for controlled release of anti-cancer drugs such as doxorubicin (DOX). The loading efficiency of doxorubicin into test beads was measured via UV-vis spectroscopy analysis and was found to be high. The formation of silver nanoparticles on the GO sheets and structural characteristics were evaluated via FT-IR, TEM, XRD, and SEM techniques. In addition, the antibacterial activity, swelling and drug release profiles of prepared nanocomposite beads were evaluated. Also, in vitro drug release test was performed in order to investigate the efficiency of CH/GO-Ag nanocomposite hydrogel beads as a drug carrier for controlled release of anti-cancer drugs such as doxorubicin (DOX). A more sustained and controlled drug release profile was observed for CH/GO-Ag nanocomposite hydrogel beads that enhanced by increasing the GO-Ag nanohybrid particles content. Copyright © 2018 Elsevier B.V. All rights reserved.

Quantum dots encoded Au coated polystyrene bead arranged micro-channel for multiplex arrays.

PubMed

Cao, Yuan-Cheng; Wang, Zhan; Yang, Runyu; Zou, Linling; Zhou, Zhen; Mi, Tie; Shi, Hong

2016-01-01

This paper describes a promising micro-channel multiplex immunoassay method based on the quantum dots encoded beads which requires micro-volume sample. Briefly, Au nanoparticles coated polystyrene (PS) beads were prepared and Quantum dots (QDs) were employed to encode 4 types of the PS beads by different emission wavelength QDs and various intensities. Different coding types of the beads were immobilized with different antibodies on the surface and BSA was used to block the unsatisfied sites. The antibody linked beads were then arranged in the 150 µm diameter optical capillary where the specific reactions took place before the detections. Results showed that the antibody on the Au coated surface maintains the bioactivity for the immunoreactions. Using this system, the fluorescent intensity was linear with analyte concentration in the range of 1×10(-7)-1×10(-5) mg/mL (RSD<5%, 4 repeats) and the lower detection limit reached 5×10(-8) mg/mL. It was proved to be a promising approach for the future miniaturization analytical devices. Copyright © 2015 Elsevier B.V. All rights reserved.

Novel mesalamine-loaded beads in tablets for delayed release of drug to the colon.

PubMed

Nguyen, Chien; Christensen, J Mark; Ayres, James W

2012-01-01

Novel 'beads-in-a-tablet' formulations (total weight ∼740-780 mg) have been prepared that meet USP 31 requirements for Delayed Release of mesalamine. Several methods are presented that overcome breakage of beads during tablet compaction were explored. Bead formulations comprise a combination of extrusion and spheronization to produce a relatively high drug load (80%), followed by coating (25%) with a colonic-targeted drug release polymer (polymethacrylates, Eudragit(®) S100), overcoated (3%) with hydroxypropyl methylcellulose (Opadry(®)) to improve bead binding and compactability, and using 20% coat of lactose/sodium starch glycolate (Explotab(®)) as binder/disintegrant/cushioning agent, thus allowing a sufficiently thick coating to be uniform and without being broken during tablet compaction. Then, the aforementioned beads were compressed into tablets at 1500 pounds of pressure containing 400 mg of mesalamine, and finally coating the compressed tablets with Surelease(®) (ethylcellulose):Opadry(®) = 1:0.5 ranging from 1.5-2.5% weight gain; the resulting tablets met USP 31 dissolution requirements for delayed release tablets.

Surface imprinted beads for the recognition of human serum albumin.

PubMed

Bonini, Francesca; Piletsky, Sergey; Turner, Anthony P F; Speghini, Adolfo; Bossi, Alessandra

2007-04-15

The synthesis of poly-aminophenylboronic acid (ABPA) imprinted beads for the recognition of the protein human serum albumin (HSA) is reported. In order to create homogeneous recognition sites, covalent immobilisation of the template HSA was exploited. The resulting imprinted beads were selective for HSA. The indirect imprinting factor (IF) calculated from supernatant was 1.6 and the direct IF, evaluated from the protein recovered from the beads, was 1.9. The binding capacity was 1.4 mg/g, which is comparable to commercially available affinity materials. The specificity of the HSA recognition was evaluated with competitive experiments, indicating a molar ratio 4.5/1 of competitor was necessary to displace half of the bound HSA. The recognition and binding of the imprinted beads was also tested with a complex sample, human serum and targeted removal of HSA without a loss of the other protein components was demonstrated. The easy preparation protocol of derivatised beads and a good protein recognition properties make the approach an attractive solution to analytical and bio-analytical problems in the field of biotechnology.

Anionic polymer, poly(methyl vinyl ether-maleic anhydride)-coated beads-based capture of human influenza A and B virus.

PubMed

Sakudo, Akikazu; Baba, Koichi; Tsukamoto, Megumi; Sugimoto, Atsuko; Okada, Takashi; Kobayashi, Takanori; Kawashita, Norihito; Takagi, Tatsuya; Ikuta, Kazuyoshi

2009-01-15

An anionic magnetic beads-based method was developed for the capture of human influenza A and B viruses from nasal aspirates, allantoic fluid and culture medium. A polymer, poly(methyl vinyl ether-maleic anhydride) [poly(MVE-MA)], was used to endow magnetic beads with a negative charge and bioadhesive properties. After incubation with samples containing human influenza virus, the beads were separated from supernatants by applying a magnetic field. The adsorption [corrected] of the virus by the beads was confirmed by hemagglutinin assay, immunochromatography, Western blotting, egg infection, and cell infection. Successful capture was proved using 5 H1N1 influenza A viruses, 10 H3N2 influenza A viruses, and 6 influenza B viruses. Furthermore, the infectivity in chicken embryonated eggs and Madin-Darby canine kidney (MDCK) cells of the captured human influenza virus was similar to that of the total viral quantity of starting materials. Therefore, this method of capture using magnetic beads coated with poly(MVE-MA) can be broadly used for the recovery of infectious human influenza viruses.

Adsorptive removal of Lead from water by the effective and reusable magnetic cellulose nanocomposite beads entrapping activated bentonite.

PubMed

Luo, Xiaogang; Lei, Xiaojuan; Xie, Xiuping; Yu, Bo; Cai, Ning; Yu, Faquan

2016-10-20

Many efforts have been driven to decontaminate the drinking water, and the development of efficient adsorbents with the advantages of cost-effectiveness and operating convenience for the removal of Pb(2+) from water is a major challenge. This work was aimed to explore the possibility of using cellulose-based adsorbents for efficient adsorption of Pb(2+). The millimeter-scale magnetic cellulose-based nanocomposite beads were fabricated via an optimal extrusion dropping technology by blending cellulose with the carboxyl-functionalized magnetite nanoparticles and acid-activated bentonite in NaOH/urea aqueous solution, and then they had been tested to evaluate the effectiveness in the removal of Pb(2+) from water. The effects of contact time, initial heavy metal ion concentrations, adsorption isotherms and solution pH on the sorption behavior were studied. The thermodynamic parameters (ΔG, ΔH and ΔS) indicated that the adsorption processes were feasible, spontaneous, endothermic and mainly controlled by chemical mechanisms. The reusability of the adsorbent was also studied. Copyright © 2016 Elsevier Ltd. All rights reserved.

[DNA quantification of blood samples pre-treated with pyramidon].

PubMed

Zhu, Chuan-Hong; Zheng, Dao-Li; Ni, Rao-Zhi; Wang, Hai-Sheng; Ning, Ping; Fang, Hui; Liu, Yan

2014-06-01

To study DNA quantification and STR typing of samples pre-treated with pyramidon. The blood samples of ten unrelated individuals were anticoagulated in EDTA. The blood stains were made on the filter paper. The experimental groups were divided into six groups in accordance with the storage time, 30 min, 1 h, 3 h, 6 h, 12 h and 24h after pre-treated with pyramidon. DNA was extracted by three methods: magnetic bead-based extraction, QIAcube DNA purification method and Chelex-100 method. The quantification of DNA was made by fluorescent quantitative PCR. STR typing was detected by PCR-STR fluorescent technology. In the same DNA extraction method, the sample DNA decreased gradually with times after pre-treatment with pyramidon. In the same storage time, the DNA quantification in different extraction methods had significant differences. Sixteen loci DNA typing were detected in 90.56% of samples. Pyramidon pre-treatment could cause DNA degradation, but effective STR typing can be achieved within 24 h. The magnetic bead-based extraction is the best method for STR profiling and DNA extraction.

Intracellular protein determination using droplet-based immunoassays.

PubMed

Martino, Chiara; Zagnoni, Michele; Sandison, Mairi E; Chanasakulniyom, Mayuree; Pitt, Andrew R; Cooper, Jonathan M

2011-07-01

This paper describes the implementation of a sensitive, on-chip immunoassay for the analysis of intracellular proteins, developed using microdroplet technology. The system offers a number of analytical functionalities, enabling the lysis of low cell numbers, as well as protein detection and quantification, integrated within a single process flow. Cells were introduced into the device in suspension and were electrically lysed in situ. The cell lysate was subsequently encapsulated together with antibody-functionalized beads into stable, water-in-oil droplets, which were stored on-chip. The binding of intracellular proteins to the beads was monitored fluorescently. By analyzing many individual droplets and quantifying the data obtained against standard additions, we measured the level of two intracellular proteins, namely, HRas-mCitrine, expressed within HEK-293 cells, and actin-EGFP, expressed within MCF-7 cells. We determined the concentrations of these proteins over 5 orders of magnitude, from ~50 pM to 1 μM. The results from this semiautomated method were compared to those for determinations made using Western blots, and were found not only to be faster, but required a smaller number of cells.

Beads-on-String Structured Nanofibers for Smart and Reversible Oil/Water Separation with Outstanding Antifouling Property.

PubMed

Wang, Yuanfeng; Lai, Chuilin; Wang, Xiaowen; Liu, Yang; Hu, Huawen; Guo, Yujuan; Ma, Kaikai; Fei, Bin; Xin, John H

2016-09-28

It is challenging to explore a unified solution for the treatment of oily wastewater from complex sources. Thus, membrane materials with flexible separation schemes are highly desired. Herein, we fabricated a smart membrane by electrospinning TiO2 doped polyvinylidene fluoride (PVDF) nanofibers. The as-formed beads-on-string structure and hierarchical roughness of the nanofibers contribute to its superwetting/resisting property to liquids, which is desirable in oil/water separation. Switched simply by UV (or sunlight) irradiation and heating treatment, the smart membrane can realize reversible separation of oil/water mixtures by selectively allowing water or oil to pass through alone. Most importantly, the as-prepared nanofiber membrane possesses outstanding antifouling and self-cleaning performance resulting from the photocatalytic property of TiO2, which has practical significance in saving solvents and recycling materials. This work provides a route for fabricating cost-effective, easily scaled up, and recyclable membranes for on-demand oil/water separation in versatile situations, which can be of great usage in the new green separation technology.

Molecular computational elements encode large populations of small objects

NASA Astrophysics Data System (ADS)

Prasanna de Silva, A.; James, Mark R.; McKinney, Bernadine O. F.; Pears, David A.; Weir, Sheenagh M.

2006-10-01

Since the introduction of molecular computation, experimental molecular computational elements have grown to encompass small-scale integration, arithmetic and games, among others. However, the need for a practical application has been pressing. Here we present molecular computational identification (MCID), a demonstration that molecular logic and computation can be applied to a widely relevant issue. Examples of populations that need encoding in the microscopic world are cells in diagnostics or beads in combinatorial chemistry (tags). Taking advantage of the small size (about 1nm) and large `on/off' output ratios of molecular logic gates and using the great variety of logic types, input chemical combinations, switching thresholds and even gate arrays in addition to colours, we produce unique identifiers for members of populations of small polymer beads (about 100μm) used for synthesis of combinatorial libraries. Many millions of distinguishable tags become available. This method should be extensible to far smaller objects, with the only requirement being a `wash and watch' protocol. Our focus on converting molecular science into technology concerning analog sensors, turns to digital logic devices in the present work.

Molecular computational elements encode large populations of small objects.

PubMed

de Silva, A Prasanna; James, Mark R; McKinney, Bernadine O F; Pears, David A; Weir, Sheenagh M

2006-10-01

Since the introduction of molecular computation, experimental molecular computational elements have grown to encompass small-scale integration, arithmetic and games, among others. However, the need for a practical application has been pressing. Here we present molecular computational identification (MCID), a demonstration that molecular logic and computation can be applied to a widely relevant issue. Examples of populations that need encoding in the microscopic world are cells in diagnostics or beads in combinatorial chemistry (tags). Taking advantage of the small size (about 1 nm) and large 'on/off' output ratios of molecular logic gates and using the great variety of logic types, input chemical combinations, switching thresholds and even gate arrays in addition to colours, we produce unique identifiers for members of populations of small polymer beads (about 100 microm) used for synthesis of combinatorial libraries. Many millions of distinguishable tags become available. This method should be extensible to far smaller objects, with the only requirement being a 'wash and watch' protocol. Our focus on converting molecular science into technology concerning analog sensors, turns to digital logic devices in the present work.

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

PubMed Central

Dick, Jeffrey E.; Hilterbrand, Adam T.; Boika, Aliaksei; Upton, Jason W.; Bard, Allen J.

2015-01-01

We report observations of stochastic collisions of murine cytomegalovirus (MCMV) on ultramicroelectrodes (UMEs), extending the observation of discrete collision events on UMEs to biologically relevant analytes. Adsorption of an antibody specific for a virion surface glycoprotein allowed differentiation of MCMV from MCMV bound by antibody from the collision frequency decrease and current magnitudes in the electrochemical collision experiments, which shows the efficacy of the method to size viral samples. To add selectivity to the technique, interactions between MCMV, a glycoprotein-specific primary antibody to MCMV, and polystyrene bead “anchors,” which were functionalized with a secondary antibody specific to the Fc region of the primary antibody, were used to affect virus mobility. Bead aggregation was observed, and the extent of aggregation was measured using the electrochemical collision technique. Scanning electron microscopy and optical microscopy further supported aggregate shape and extent of aggregation with and without MCMV. This work extends the field of collisions to biologically relevant antigens and provides a novel foundation upon which qualitative sensor technology might be built for selective detection of viruses and other biologically relevant analytes. PMID:25870261

Magnetophoretic Conductors and Diodes in a 3D Magnetic Field.

PubMed

Abedini-Nassab, Roozbeh; Joh, Daniel Y; Van Heest, Melissa; Baker, Cody; Chilkoti, Ashutosh; Murdoch, David M; Yellen, Benjamin B

2016-06-14

We demonstrate magnetophoretic conductor tracks that can transport single magnetized beads and magnetically labeled single cells in a 3-dimensional time-varying magnetic field. The vertical field bias, in addition to the in-plane rotating field, has the advantage of reducing the attraction between particles, which inhibits the formation of particle clusters. However, the inclusion of a vertical field requires the re-design of magnetic track geometries which can transport magnetized objects across the substrate. Following insights from magnetic bubble technology, we found that successful magnetic conductor geometries defined in soft magnetic materials must be composed of alternating sections of positive and negative curvature. In addition to the previously studied magnetic tracks taken from the magnetic bubble literature, a drop-shape pattern was found to be even more adept at transporting small magnetic beads and single cells. Symmetric patterns are shown to achieve bi-directional conduction, whereas asymmetric patterns achieve unidirectional conduction. These designs represent the electrical circuit corollaries of the conductor and diode, respectively. Finally, we demonstrate biological applications in transporting single cells and in the size based separation of magnetic particles.

Drug particle size influence on enteric beads produced by a droplet extrusion/precipitation method.

PubMed

Cerdeira, A M; Gouveia, L F; Goucha, P; Almeida, A J

2000-01-01

The influence of drug particle size on the production of enteric beads by a polymer precipitation technique was investigated. Drug particle dimensions are known to play an important role in most microencapsulation techniques. Bead morphology was greatly influenced by drug particle size, and spherical shaped beads could only be obtained after size reduction of nimesulide crystals. This is confirmed by the angle of repose measurements, which show a significant decrease in theta values when beads are formulated with smaller drug particles. Furthermore, results show that drug encapsulation efficiency and in vitro drug release rates are also greatly dependent on both drug particle size and drug/polymer ratio in the initial suspension. Preparations containing 10.2 microm drug particles show a two-fold increase in the release rates when compared to those prepared with 40 microm particles.

Two-phase mixed media dielectric with macro dielectric beads for enhancing resistivity and breakdown strength

DOEpatents

Falabella, Steven; Meyer, Glenn A; Tang, Vincent; Guethlein, Gary

2014-06-10

A two-phase mixed media insulator having a dielectric fluid filling the interstices between macro-sized dielectric beads packed into a confined volume, so that the packed dielectric beads inhibit electro-hydrodynamically driven current flows of the dielectric liquid and thereby increase the resistivity and breakdown strength of the two-phase insulator over the dielectric liquid alone. In addition, an electrical apparatus incorporates the two-phase mixed media insulator to insulate between electrical components of different electrical potentials. And a method of electrically insulating between electrical components of different electrical potentials fills a confined volume between the electrical components with the two-phase dielectric composite, so that the macro dielectric beads are packed in the confined volume and interstices formed between the macro dielectric beads are filled with the dielectric liquid.

Hot spot formation from shock reflections

NASA Astrophysics Data System (ADS)

Menikoff, R.

2011-04-01

Heterogeneities sensitize an explosive to shock initiation. This is due to hot-spot formation and the sensitivity of chemical reaction rates to temperature. Here, we describe a numerical experiment aimed at elucidating a mechanism for hot-spot formation that occurs when a shock wave passes over a high-density impurity. The simulation performed is motivated by a physical experiment in which glass beads are added to liquid nitromethane. The impedance mismatch between the beads and the nitromethane results in shock reflections. These, in turn, give rise to transverse waves along the lead shock front. Hot spots arise on local portions of the lead front with a higher shock strength, rather than on the reflected shocks behind the beads. Moreover, the interactions generated by reflected waves from neighboring beads can significantly increase the peak hot-spot temperature when the beads are suitably spaced.

Glass bead cultivation of fungi: combining the best of liquid and agar media.

PubMed

Droce, Aida; Sørensen, Jens Laurids; Giese, Henriette; Sondergaard, Teis Esben

2013-09-01

Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads that allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier than from agar plates and the quality was superior. The system allows simple control of nutrient availability throughout fungal cultivation. This combined with the ease of extraction of nucleic acids and metabolites makes the system highly suitable for the study of gene regulation in response to specific nutrient factors. © 2013.

Holographic optical tweezers for object manipulations at an air-liquid surface.

PubMed

Jesacher, Alexander; Fürhapter, Severin; Maurer, Christian; Bernet, Stefan; Ritsch-Marte, Monika

2006-06-26

We investigate holographic optical tweezers manipulating micro-beads at a suspended air-liquid interface. Axial confinement of the particles in the two-dimensional interface is maintained by the interplay between surface tension and gravity. Therefore, optical trapping of the micro-beads is possible even with a long distance air objective. Efficient micro-circulation of the liquid can be induced by fast rotating beads, driven by the orbital angular momentum transfer of incident Laguerre-Gaussian (doughnut) laser modes. Our setup allows various ways of creating a tailored dynamic flow of particles and liquid within the surface. We demonstrate examples of surface manipulations like efficient vortex pumps and mixers, interactive particle flow steering by arrays of vortex pumps, the feasibility of achieving a "clocked" traffic of micro beads, and size-selective guiding of beads along optical "conveyor belts".

Bead-bead interaction parameters in dissipative particle dynamics: Relation to bead-size, solubility parameter, and surface tension

NASA Astrophysics Data System (ADS)

Maiti, Amitesh; McGrother, Simon

2004-01-01

Dissipative particle dynamics (DPD) is a mesoscale modeling method for simulating equilibrium and dynamical properties of polymers in solution. The basic idea has been around for several decades in the form of bead-spring models. A few years ago, Groot and Warren [J. Chem. Phys. 107, 4423 (1997)] established an important link between DPD and the Flory-Huggins χ-parameter theory for polymer solutions. We revisit the Groot-Warren theory and investigate the DPD interaction parameters as a function of bead size. In particular, we show a consistent scheme of computing the interfacial tension in a segregated binary mixture. Results for three systems chosen for illustration are in excellent agreement with experimental results. This opens the door for determining DPD interactions using interfacial tension as a fitting parameter.

Chromium (VI) ion adsorption by grafted cross-linked chitosan beads in aqueous solution - a mathematical and statistical modeling study.

PubMed

Igberase, E; Osifo, P; Ofomaja, A

2017-12-01

Chitosan outstanding qualities and efficient way of binding metal ions even to near zero concentration is the major reason for special attention. Modification of chitosan allows the polymer to be applied in numerous field of research. Depending on the modification techniques, chitosan possesses increased adsorption capacity. In this study chitosan beads (CS) were formulated from chitosan flakes, the beads were cross-linked with glutaraldehyde and thereafter grafted with ethyldiaminetetraacetic acid. The stability and amine concentration of the beads were determined. The chemical functionalities of the beads were obtained by Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis (TGA). However, in the adsorption studies with Cr(VI), the number of runs in the experiment was obtained by response surface methodology (RSM), and the maximum adsorption capacity (Q m ) from each run was determined from the Langmuir model. The results of the experiment showed that the non-modified beads were soluble at pH 1-4 and insoluble at pH 5, while the modified beads were insoluble at pH 1-6. The amine concentration of CS, CCS and grafted cross-linked chitosan beads (GCCS) were 4.4, 3.8 and 5.0 mmol/g, respectively. The point of zero charge (pH PZC ) of GCCS was found to be 4.4. The quadratic model was significant and adequate in describing the experimental data. The difference between experimental and predicted Q m was negligible. From the design matrix and results, increased Q m was achieved at pH 5, contact time 70 min, temperature 45°C, adsorbent dosage 5 g and initial concentration 70 mg/l. The desorption of the beads loaded with Cr(VI) was successful with 0.5 M HCl eluant and contact time of 180 min, leading to cost minimization.

Magnetic Levitation as a Platform for Competitive Protein-Ligand Binding Assays

PubMed Central

Shapiro, Nathan D.; Soh, Siowling; Mirica, Katherine A.; Whitesides, George M.

2012-01-01

This paper describes a method based on magnetic levitation (MagLev) that is capable of indirectly measuring the binding of unlabeled ligands to unlabeled protein. We demonstrate this method by measuring the affinity of unlabeled bovine carbonic anhydrase (BCA) for a variety of ligands (most of which are benzene sulfonamide derivatives). This method utilizes porous gel beads that are functionalized with a common aryl sulfonamide ligand. The beads are incubated with BCA and allowed to reach an equilibrium state in which the majority of the immobilized ligands are bound to BCA. Since the beads are less dense than the protein, protein binding to the bead increases the overall density of the bead. This change in density can be monitored using MagLev. Transferring the beads to a solution containing no protein creates a situation where net protein efflux from the bead is thermodynamically favorable. The rate at which protein leaves the bead for the solution can be calculated from the rate at which the levitation height of the bead changes. If another small molecule ligand of BCA is dissolved in the solution, the rate of protein efflux is accelerated significantly. This paper develops a reaction-diffusion (RD) model to explain both this observation, and the physical-organic chemistry that underlies it. Using this model, we calculate the dissociation constants of several unlabeled ligands from BCA, using plots of levitation height versus time. Notably, although this method requires no electricity, and only a single piece of inexpensive equipment, it can measure accurately the binding of unlabeled proteins to small molecules over a wide range of dissociation constants (Kd’s within the range of ~ 10 nM to 100 µM are measured easily). Assays performed using this method generally can be completed within a relatively short time period (20 minutes – 2 hours). A deficiency of this system is that it is not, in its present form, applicable to proteins with molecular weight greater than approximately 65 kDa. PMID:22686324

Magnetic levitation as a platform for competitive protein-ligand binding assays.

PubMed

Shapiro, Nathan D; Soh, Siowling; Mirica, Katherine A; Whitesides, George M

2012-07-17

This paper describes a method based on magnetic levitation (MagLev) that is capable of indirectly measuring the binding of unlabeled ligands to unlabeled protein. We demonstrate this method by measuring the affinity of unlabeled bovine carbonic anhydrase (BCA) for a variety of ligands (most of which are benzene sulfonamide derivatives). This method utilizes porous gel beads that are functionalized with a common aryl sulfonamide ligand. The beads are incubated with BCA and allowed to reach an equilibrium state in which the majority of the immobilized ligands are bound to BCA. Since the beads are less dense than the protein, protein binding to the bead increases the overall density of the bead. This change in density can be monitored using MagLev. Transferring the beads to a solution containing no protein creates a situation where net protein efflux from the bead is thermodynamically favorable. The rate at which protein leaves the bead for the solution can be calculated from the rate at which the levitation height of the bead changes. If another small molecule ligand of BCA is dissolved in the solution, the rate of protein efflux is accelerated significantly. This paper develops a reaction-diffusion (RD) model to explain both this observation, and the physical-organic chemistry that underlies it. Using this model, we calculate the dissociation constants of several unlabeled ligands from BCA, using plots of levitation height versus time. Notably, although this method requires no electricity, and only a single piece of inexpensive equipment, it can measure accurately the binding of unlabeled proteins to small molecules over a wide range of dissociation constants (K(d) values within the range from ~10 nM to 100 μM are measured easily). Assays performed using this method generally can be completed within a relatively short time period (20 min-2 h). A deficiency of this system is that it is not, in its present form, applicable to proteins with molecular weight greater than approximately 65 kDa.

Complementary notes on a `well-known' marine heterotrichous ciliate, Folliculinopsis producta (Wright, 1859) Frauré-Fremiet, 1936 (Protozoa, ciliophora)

NASA Astrophysics Data System (ADS)

Ji, Daode; Lin, Xiaofeng; Song, Weibo

2004-04-01

The living morphology and infraciliature of a heterotrichous ciliate, Folliculinopsis producta (Wright, 1859) Frauré-Fremiet, 1936, which was collected from the north coast of China, were investigated by in vivo observation and protargol impregnation techniques. As a new contribution, a redescription is presented: large Folliculinopsis of green to dark green in color, 800 1500µmn in size; two peristomial lobes of approximately equal size, 300 400µm in length; adoral zone of membranelles containing about 1000 membranelles, lying along lobe margins and exhibiting two circles within buccal cavity; 50 70 somatic kineties in mid-body; macronucleus miniliform, consisting of about 20 beads; lorica smooth, vase-shaped, (300 500)µm × (90 130)µm in size, with 5 12 spiral ridges on neck tube; marine habitat.

Antibody-ribosome-mRNA (ARM) complexes as efficient selection particles for in vitro display and evolution of antibody combining sites.

PubMed Central

He, M; Taussig, M J

1997-01-01

We describe a rapid, eukaryotic, in vitro method for selection and evolution of antibody combining sites using antibody-ribosome-mRNA (ARM) complexes as selection particles. ARMs carrying single-chain (VH/K) binding fragments specific for progesterone were selected using antigen-coupled magnetic beads; selection simultaneously captured the genetic information as mRNA, making it possible to generate and amplify cDNA by single-step RT-PCR on the ribosome-bound mRNA for further manipulation. Using mutant libraries, antigen-binding ARMs were enriched by a factor of 10(4)-10(5)-fold in a single cycle, with further enrichment in repeated cycles. While demonstrated here for antibodies, the method has the potential to be applied equally for selection of receptors or peptides from libraries. PMID:9396828

Antibody-ribosome-mRNA (ARM) complexes as efficient selection particles for in vitro display and evolution of antibody combining sites.

PubMed

He, M; Taussig, M J

1997-12-15

We describe a rapid, eukaryotic, in vitro method for selection and evolution of antibody combining sites using antibody-ribosome-mRNA (ARM) complexes as selection particles. ARMs carrying single-chain (VH/K) binding fragments specific for progesterone were selected using antigen-coupled magnetic beads; selection simultaneously captured the genetic information as mRNA, making it possible to generate and amplify cDNA by single-step RT-PCR on the ribosome-bound mRNA for further manipulation. Using mutant libraries, antigen-binding ARMs were enriched by a factor of 10(4)-10(5)-fold in a single cycle, with further enrichment in repeated cycles. While demonstrated here for antibodies, the method has the potential to be applied equally for selection of receptors or peptides from libraries.

Non-equilibrium plasma reactors for organic solvent destruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, C.L.; Beltran, M.R.; Kravets, Z.

1997-12-31

Two non-equilibrium plasma reactors were evaluated for their ability to destroy three widely used organic solvents, i.e., 2-butanone, toluene and ethyl acetate. The catalyzed plasma reactor (CPR) with 6 mm glass beads destroys 98% of 50 ppm toluene in air at 24 kV/cm and space velocities of 1,400 v/v/hr. Eighty-five percent of ethyl acetate and 2-butanone are destroyed under the same conditions. The tubular plasma reactor (TPR) has an efficiency of 10% to 20% lower than that of a CPR under the same conditions. The 1,400 v/v/hr in a CPR is equal to a residence time of 2.6 seconds inmore » a TPR. The operating temperatures, corona characteristics, as well as the kinetics of VOC destruction in both TPR and CPR were studied.« less

Comparison of the electrochemical properties of various orthopedic porous metals.

PubMed

Warren, L D; Chowdhary, P R

1992-01-01

The electrochemical properties of various porous metal coatings used in reconstructive orthopedic prosthetics were examined. Potentiodynamic corrosion testing was used to evaluate the behavior of the following porous metals; CSTi on Cast CoCr, CSTi on Ti-6Al-4V, CoCr beads on Cast CoCr, CoCr beads on Ti-6Al-4V, CP Ti beads on Cast CoCr, and CP Ti beads on Ti-6Al-4V. Analysis of the resultant corrosion scans showed that these materials behave similarly to one another. No corrosion-related anomalies were noted.

Molecularly Imprinted Polymers Chitosan-Glutaraldehyde for Monosodium Glutamate

NASA Astrophysics Data System (ADS)

Mulyasuryani, Ani; Haryanto, Edi; Sulistyarti, Hermin; Rumhayati, Barlah

2018-01-01

Chitosan has been used as a functional monomer in the synthesis of molecularly imprinted polymers (MIP) for monosodium glutamate (MSG). MIP is made from a mixture of 5 g chitosan, 50 mg glutaraldehyde and 2 g MSG, MIP is formed as flakes and beads. MIPs are identified by the FTIR spectrum, SEM image and their adsorption capabilities. MIP flakes and beads have no structural differences if they are based on FTIR or SEM spectra, but MIP adsorption capacity of beads higher than flakes. Adsorption capacity of MIP flakes is 548 mg/g and MIP beads 627 mg/g.

Parallel manipulation of individual magnetic microbeads for lab-on-a-chip applications

NASA Astrophysics Data System (ADS)

Peng, Zhengchun

Many scientists and engineers are turning to lab-on-a-chip systems for faster and cheaper analysis of chemical reactions and biomolecular interactions. A common approach that facilitates the handling of reagents and biomolecules in these systems utilizes micro/nano beads as the solid carrier. Physical manipulation, such as assembly, transport, sorting, and tweezing, of beads on a chip represents an essential step for fully utilizing their potentials in a wide spectrum of bead-based analysis. Previous work demonstrated manipulation of either an ensemble of beads without individual control, or single beads but lacks the capability for parallel operation. Parallel manipulation of individual beads is required to meet the demand for high-throughput and location-specific analysis. In this work, we introduced two methods for parallel manipulation of individual magnetic microbeads, which can serve as effective lab-on-a-chip platforms and/or efficient analytic tools. The first method employs arrays of soft ferromagnetic patterns fabricated inside a microfluidic channel and subjected to an external magnetic field. We demonstrated that the system can be used to assemble individual beads (1-3 mum) from a flow of suspended beads into a regular array on the chip, hence improving the integrated electrochemical detection of biomolecules bound to the bead surface. By rotating the external field, the assembled microbeads can be remotely controlled with synchronized, high-speed circular motion around individual soft magnets on the chip. We employed this manipulation mode for efficient sample mixing in continuous microflow. Furthermore, we discovered a simple but effective way of transporting the microbeads on the chip by varying the strength of the local bias field within a revolution of the external field. In addition, selective transport of microbeads with different size was realized, providing a platform for effective on-chip sample separation and offering the potential for multiplexing capability. The second method integrates magnetic and dielectrophoretic manipulations of the same microbeads. The device combines tapered conducting wires and fingered electrodes to generate desirable magnetic and electric fields, respectively. By externally programming the magnetic attraction and dielectrophoretic repulsion forces, out-of-plane oscillation of the microbeads across the channel height was realized. This manipulation mode can facilitate the interaction between the beads with multiple layers of sample fluid inside the channel. We further demonstrated the tweezing of microbeads in liquid with high spatial resolutions, i.e., from submicrometer to nanometer range, by fine-tuning the net force from magnetic attraction and dielectrophoretic repulsion of the beads. The highresolution control of the out-of-plane motion of the microbeads led to the invention of massively parallel biomolecular tweezers. We believe the maturation of bead-based microtweezers will revolutionize the state-of-art tools currently used for single cell and single molecule studies.

A semi-automated multiplex high-throughput assay for measuring IgG antibodies against Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) domains in small volumes of plasma.

PubMed

Cham, Gerald K K; Kurtis, Jonathan; Lusingu, John; Theander, Thor G; Jensen, Anja T R; Turner, Louise

2008-06-12

The level of antibodies against PfEMP1 is routinely quantified by the conventional microtitre enzyme-linked immunosorbent assay (ELISA). However, ELISA only measures one analyte at a time and requires a relatively large plasma volume if the complete antibody profile of the sample is to be obtained. Furthermore, assay-to-assay variation and the problem of storage of antigen can influence ELISA results. The bead-based assay described here uses the BioPlex100 (BioRad, Hercules, CA, USA) system which can quantify multiple antibodies simultaneously in a small plasma volume. A total of twenty nine PfEMP1 domains were PCR amplified from 3D7 genomic DNA, expressed in the Baculovirus system and purified by metal-affinity chromatography. The antibody reactivity level to the recombinant PfEMP1 proteins in human hyper-immune plasma was measured by ELISA. In parallel, these recombinant PfEMP1 proteins were covalently coupled onto beads each having its own unique detection signal and the human hyper-immune plasma reactivity was detected for each individual protein using a BioPlex100 system. Protein-coupled beads were analysed at two time points seven months apart, before and after lyophilization and the results compared to determine the effect of storage and lyophilization respectively on the beads. Multiplexed protein-coupled beads from twenty eight unique bead populations were evaluated on the BioPlex100 system against pooled human hyper-immune plasma before and after lyophilization. The bead-based assay was sensitive, accurate and reproducible. Four recombinant PfEMP1 proteins C17, D5, D9 and D12, selected on the basis that they showed a spread of median fluorescent intensity (MFI) values from low to high when analysed by the bead-based assay were analysed by ELISA and the results from both analyses were highly correlated. The Spearman's rank correlation coefficients (Rho) were > or = 0.86, (P < 0.0001) for all comparisons. Bead-based assays gave similar results regardless of whether they were performed on individual beads or on multiplexed beads; lyophilization had no impact on the assay performance. Spearman's rank correlation coefficients (Rho) were > or = 0.97, (P < 0.0001) for all comparisons. Importantly, the reactivity of protein-coupled non-lyophilized beads decreased with long term storage at 4 degrees C in the dark. Using this lyophilized multiplex assay, antibody reactivity levels to twenty eight different recombinant PfEMP1 proteins were simultaneously measured using a single microliter of plasma. Thus, the assay reported here provides a useful tool for rapid and efficient quantification of antibody reactivity against PfEMP1 variants in human plasma.

A Mathematical Model for Simulating Remediation of Groundwater Contaminated by Heavy Metals using Bio-Carriers with Dead Baccilus sp. B1 and Polysulfone

NASA Astrophysics Data System (ADS)

Seo, H.; Wang, S.; Lee, M.

2010-12-01

The remediation of groundwater contaminated by heavy metals, organic contaminants, etc. using various types of bio-carriers has been widely studied as a novel technology in the literature. In this study, a series of batch experiments were conducted to investigated the fundamental characteristics in the removal process using bio-carriers (beads) with dead Bacillus sp. B1 and polysulfone. Through equilibrium and kinetic sorption experiments, sorption efficiencies for lead and copper under various conditions such as pH, temperature, contaminant concentration, etc. were examined and sorption parameters including maximum sorption capacities were obtained for model applications. Experimental data showed that equilibrium sorption patterns for Pb2+and Cu2+on bio-carrier beads follows Langmuir sorption isotherm and that the sorption dynamics can be described with a pseudo-second-order kinetics. One dimensional advective-dispersive-reactive transport model was also developed for simulating and analyzing the remediation processes. The HSDM (homogeneous surface diffusion model) were incorporated in the model to take into account the mass transfer and sorption mechanisms around/inside the bio-carrier beads. Applying the proposed model, numerical column experiments were carried out and the simulation results reasonably described temporal and spatial distribution of Pb2+and Cu2+in a fixed-bed flow-through sorption column. Experimental and numerical results showed that the main mechanism of the bio-carrier to remove heavy metals is the sorption on/inside of the bio-carriers and the bio-carriers can function as excellent biosorbents for the removal of heavy metal ions from groundwater.

Controlled Release of 5-Fluorouracil from Alginate Beads Encapsulated in 3D Printed pH-Responsive Solid Dosage Forms.

PubMed

Gioumouxouzis, Christos I; Chatzitaki, Aikaterini-Theodora; Karavasili, Christina; Katsamenis, Orestis L; Tzetzis, Dimitrios; Mystiridou, Emmanouela; Bouropoulos, Nikolaos; Fatouros, Dimitrios G

2018-06-14

Three-dimensional printing is being steadily deployed as manufacturing technology for the development of personalized pharmaceutical dosage forms. In the present study, we developed a hollow pH-responsive 3D printed tablet encapsulating drug loaded non-coated and chitosan-coated alginate beads for the targeted colonic delivery of 5-fluorouracil (5-FU). A mixture of Eudragit® L100-55 and Eudragit® S100 was fabricated by means of hot-melt extrusion (HME) and the produced filaments were printed utilizing a fused deposition modeling (FDM) 3D printer to form the pH-responsive layer of the tablet with the rest comprising of a water-insoluble poly-lactic acid (PLA) layer. The filaments and alginate particles were characterized for their physicochemical properties (thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction), their surface topography was visualized by scanning electron microscopy and the filaments' mechanical properties were assessed by instrumented indentation testing and tensile testing. The optimized filament formulation was 3D printed and the structural integrity of the hollow tablet in increasing pH media (pH 1.2 to pH 7.4) was assessed by means of time-lapsed microfocus computed tomography (μCT). In vitro release studies demonstrated controlled release of 5-FU from the alginate beads encapsulated within the hollow pH-sensitive tablet matrix at pH values corresponding to the colonic environment (pH 7.4). The present study highlights the potential of additive manufacturing in fabricating controlled-release dosage forms rendering them pertinent formulations for further in vivo evaluation.

Extraction and labeling methods for microarrays using small amounts of plant tissue.

PubMed

Stimpson, Alexander J; Pereira, Rhea S; Kiss, John Z; Correll, Melanie J

2009-03-01

Procedures were developed to maximize the yield of high-quality RNA from small amounts of plant biomass for microarrays. Two disruption techniques (bead milling and pestle and mortar) were compared for the yield and the quality of RNA extracted from 1-week-old Arabidopsis thaliana seedlings (approximately 0.5-30 mg total biomass). The pestle and mortar method of extraction showed enhanced RNA quality at the smaller biomass samples compared with the bead milling technique, although the quality in the bead milling could be improved with additional cooling steps. The RNA extracted from the pestle and mortar technique was further tested to determine if the small quantity of RNA (500 ng-7 microg) was appropriate for microarray analyses. A new method of low-quantity RNA labeling for microarrays (NuGEN Technologies, Inc.) was used on five 7-day-old seedlings (approximately 2.5 mg fresh weight total) of Arabidopsis that were grown in the dark and exposed to 1 h of red light or continued dark. Microarray analyses were performed on a small plant sample (five seedlings; approximately 2.5 mg) using these methods and compared with extractions performed with larger biomass samples (approximately 500 roots). Many well-known light-regulated genes between the small plant samples and the larger biomass samples overlapped in expression changes, and the relative expression levels of selected genes were confirmed with quantitative real-time polymerase chain reaction, suggesting that these methods can be used for plant experiments where the biomass is extremely limited (i.e. spaceflight studies).

Bio-absorbable antibiotic impregnated beads for the treatment of prosthetic vascular graft infections.

PubMed

Genovese, Elizabeth A; Avgerinos, Efthymios D; Baril, Donald T; Makaroun, Michel S; Chaer, Rabih A

2016-12-01

There is limited investigation into the use of bio-absorbable antibiotic beads for the treatment of prosthetic vascular graft infections. Our goal was to investigate the rates of infection eradication, graft preservation, and limb salvage in patients who are not candidates for graft explant or extensive reconstruction. A retrospective review of patients implanted with antibiotic impregnated bio-absorbable calcium sulfate beads at a major university center was conducted. Six patients with prosthetic graft infections were treated with bio-absorbable antibiotics beads from 2012-2014. Grafts included an aortobifemoral, an aorto-hepatic/superior mesenteric artery, and four extra-anatomic bypasses. Pathogens included Gram-positive and Gram-negative bacteria. Half of the patients underwent graft explant with reconstruction and half debridement of the original graft, all with antibiotic bead placement around the graft. Mean follow-up was 7.3 ± 8.3 months; all patients had infection resolution, healed wounds, and 100% graft patency, limb salvage, and survival. This report details the successful use of bio-absorbable antibiotic beads for the treatment prosthetic vascular graft infections in patients at high risk for graft explant or major vascular reconstruction. At early follow-up, we demonstrate successful infection suppression, graft preservation, and limb salvage with the use of these beads in a subset of vascular patients. © The Author(s) 2016.