High Trapping Efficiency Research Articles

An assessment of mosquito collection techniques for xenomonitoring of anopheline-transmitted Lymphatic Filariasis in Ghana.

Monitoring vectors is relevant to ascertain transmission of lymphatic filariasis (LF). This may require the best sampling method that can capture high numbers of specific species to give indication of transmission. Gravid anophelines are good indicators for assessing transmission due to close contact with humans through blood meals. This study compared the efficiency of an Anopheles gravid trap (AGT) with other mosquito collection methods including the box and the Centres for Disease Control and Prevention gravid, light, exit and BioGent-sentinel traps, indoor resting collection (IRC) and pyrethrum spray catches across two endemic regions of Ghana. The AGT showed high trapping efficiency by collecting the highest mean number of anophelines per night in the Western (4.6) and Northern (7.3) regions compared with the outdoor collection methods. Additionally, IRC was similarly efficient in the Northern region (8.9) where vectors exhibit a high degree of endophily. AGT also showed good trapping potential for collecting Anopheles melas which is usually difficult to catch with existing methods. Screening of mosquitoes for infection showed a 0.80-3.01% Wuchereria bancrofti and 2.15-3.27% Plasmodium spp. in Anopheles gambiae. The AGT has shown to be appropriate for surveying Anopheles populations and can be useful for xenomonitoring for both LF and malaria.

Experimental study on the impact of electrostatic effect on the movement of charged particles

In this research, the Electrostatic-bag-precipitator (EBP) platform was made of the fully transparent organic glass materials, and the Particle Image Velocimetry (PIV) device was used to carry out the direct test of the charged particles movement in the precipitator. The Electrical Low Pressure Impactor (ELPI+) was applied to test the charge amounts of the outlet of the electrostatic precipitator (ESP) part and the outlet of EBP simultaneously. It was found that the movement of charged particles was both affected by the electrostatic repulsion among the particles and the charged dust layer on the filter cartridges, and the effect was positively correlated with the charge amounts on the particles and the dust layer. The variation law of cumulative charge amounts of the dust layer under different voltages and during different time phases was analyzed indirectly and the corresponding function model was established, hoping to provide reference for the research on the high-efficient trapping technique of fine particles.

Finite Element Simulation of Microfluidic Biochip for High Throughput Hydrodynamic Single Cell Trapping

In this paper, a microfluidic device capable of trapping a single cell in a high throughput manner and at high trapping efficiency is designed simply through a concept of hydrodynamic manipulation. The microfluidic device is designed with a series of trap and bypass microchannel structures for trapping individual cells without the need for microwell, robotic equipment, external electric force or surface modification. In order to investigate the single cell trapping efficiency, a finite element model of the proposed design has been developed using ABAQUS-FEA software. Based on the simulation, the geometrical parameters and fluid velocity which affect the single cell trapping are extensively optimized. After optimization of the trap and bypass microchannel structures via simulations, a single cell can be trapped at a desired location efficiently.

Application technology of the sex pheromone of the tea geometrid Ectropis grisescens (Lepidoptera: Geometridae)

ABSTRACTThe sex pheromone of Ectropis grisescens, one of the primary defoliator insects of tea plantations, has been identified, but its trapping parameters have not been optimized for field application. In this study, we investigated the effects of pheromone dose, trap height and trap type on the effectiveness of trapping E. grisescens in the field. Our results show that the optimal pheromone dose is 800 μg. The bucket-funnel trap hung 40 cm below the tea canopy had the highest trapping efficiency. This study establishes optimized parameters for the pheromone trapping of E. grisescens in tea plantations.

AEgIS at ELENA: outlook for physics with a pulsed cold antihydrogen beam.

The efficient production of cold antihydrogen atoms in particle traps at CERN's Antiproton Decelerator has opened up the possibility of performing direct measurements of the Earth's gravitational acceleration on purely antimatter bodies. The goal of the AEgIS collaboration is to measure the value of g for antimatter using a pulsed source of cold antihydrogen and a Moiré deflectometer/Talbot-Lau interferometer. The same antihydrogen beam is also very well suited to measuring precisely the ground-state hyperfine splitting of the anti-atom. The antihydrogen formation mechanism chosen by AEgIS is resonant charge exchange between cold antiprotons and Rydberg positronium. A series of technical developments regarding positrons and positronium (Ps formation in a dedicated room-temperature target, spectroscopy of the n=1-3 and n=3-15 transitions in Ps, Ps formation in a target at 10 K inside the 1 T magnetic field of the experiment) as well as antiprotons (high-efficiency trapping of [Formula: see text], radial compression to sub-millimetre radii of mixed [Formula: see text] plasmas in 1 T field, high-efficiency transfer of [Formula: see text] to the antihydrogen production trap using an in-flight launch and recapture procedure) were successfully implemented. Two further critical steps that are germane mainly to charge exchange formation of antihydrogen-cooling of antiprotons and formation of a beam of antihydrogen-are being addressed in parallel. The coming of ELENA will allow, in the very near future, the number of trappable antiprotons to be increased by more than a factor of 50. For the antihydrogen production scheme chosen by AEgIS, this will be reflected in a corresponding increase of produced antihydrogen atoms, leading to a significant reduction of measurement times and providing a path towards high-precision measurements.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.

Numerical study on fine-particle charging and transport behaviour in electrostatic precipitators

In this work, a numerical study on the charging and transport of fine particles has been carried out based on wire-plate electrostatic precipitators (ESPs) with multiple wire electrodes. The effect of the applied wire voltage, inlet height, and wire spacing on particle charging and transport, and the influence of the precipitator structure on particle trapping are analysed in detail. Results indicate that a voltage increase in the high voltage range improves the particle-trapping efficiency. However, the Brownian diffusion causes the particle fluctuation, but it doesn't change the direction of main movement. Particles injected into the precipitator at the channel centre are influenced most intensively, whereas particles injected at approximately 5 mm from the centre of the precipitator exhibit the poorest particle-trapping ability. An increased wire spacing enhances particle trapping, within a certain range, and a larger particle size causes an even more obvious enhancement. Furthermore, changing the discharge-electrode arrangement shows a much greater effect on the charging and transport behaviour of particles in the model of M3, which has the highest trapping efficiency.

Impacts of large dams on the complexity of suspended sediment dynamics in the Yangtze River

The Yangtze River is one of the largest and most important rivers in the world. Over the past several decades, the natural sediment regime of the Yangtze River has been altered by the construction of dams. This paper uses multi-scale entropy analysis to ascertain the impacts of large dams on the complexity of high-frequency suspended sediment dynamics in the Yangtze River system, especially after impoundment of the Three Gorges Dam (TGD). In this study, the complexity of sediment dynamics is quantified by framing it within the context of entropy analysis of time series. Data on daily sediment loads for four stations located in the mainstem are analyzed for the past 60 years. The results indicate that dam construction has reduced the complexity of short-term (1–30 days) variation in sediment dynamics near the structures, but that complexity has actually increased farther downstream. This spatial pattern seems to reflect a filtering effect of the dams on the on the temporal pattern of sediment loads as well as decreased longitudinal connectivity of sediment transfer through the river system, resulting in downstream enhancement of the influence of local sediment inputs by tributaries on sediment dynamics. The TGD has had a substantial impact on the complexity of sediment series in the mainstem of the Yangtze River, especially after it became fully operational. This enhanced impact is attributed to the high trapping efficiency of this dam and its associated large reservoir. The sediment dynamics “signal” becomes more spatially variable after dam construction. This study demonstrates the spatial influence of dams on the high-frequency temporal complexity of sediment regimes and provides valuable information that can be used to guide environmental conservation of the Yangtze River.

A microfluidic microwell device for immunomagnetic single-cell trapping

Single-cell analysis has been widely applied in various biomedical applications, such as cancer diagnostics, immune status monitoring, and drug screening. To perform an accurate and rapid cellular analysis, various magnetic-activated cell sorting techniques are available in the markets. However, large sample requirement and uneven magnetic field distribution limit its application in single-cell trapping and following analysis. To address these problems, we developed a microfluidic microwell device for immunomagnetic single-cell trapping. By adding a microwell layer between the microchannel and magnet, the magnetic field along the device becomes more uniform. Besides, magnetic beads can be retained in the array of microwell after the high-speed washing step, whereas untrapped beads would be flushed away, resulting in high single-particle trapping efficiency (62%) and purity (99.6%). To achieve large-area single-cell trapping, we introduced a “sweeping” loading protocol to further expand the single-particle trapping range. In the microwell region near to the edge of the magnet, over 3000 single magnetic beads were trapped in a 10 mm2 area. Finally, we demonstrated immunomagnetic-labeled THP-1 cells can successfully be trapped at single-cell level in the microwell. The cell trapping process can be done in 10 min. We believe the platform with an accurate and efficient single-cell trapping functionality could potentially be used for various cellular analyses at the single-cell level.

Schamel equation in an inhomogeneous magnetized sheared flow plasma with q-nonextensive trapped electrons

An investigation is carried out for understanding the properties of ion–acoustic (IA) solitary waves in an inhomogeneous magnetized electron-ion plasma with field-aligned sheared flow under the impact of q-nonextensive trapped electrons. The Schamel equation and its stationary solution in the form of solitary waves are obtained for this inhomogeneous plasma. It is shown that the amplitude of IA solitary waves increases with higher trapping efficiency (β), while the width remains almost the same. Further, it is found that the amplitude of the solitary waves decreases with enhanced normalized drift speed, shear flow parameter and the population of the energetic particles. The size of the nonlinear solitary structures is calculated to be a few hundred meters and it is pointed out that the present results are useful to understand the solar wind plasma.

Geometrical effect characterization of femtosecond-laser manufactured glass microfluidic chips based on optical manipulation of submicroparticles

Microfluidic devices provide a platform with wide ranging applications from environmental monitoring to disease diagnosis. They offer substantive advantages but are often not optimized or designed to be used by nonexpert researchers. Microchannels of a microanalysis platform and their geometrical characterization are of eminent importance when designing such devices. We present a method that is used to optimize each microchannel within a device using high-throughput particle manipulation. For this purpose, glass-based microfluidic devices, with three-dimensional channel networks of several geometrical sizes, were fabricated by employing laser fabrication techniques. The effect of channel geometry was investigated by employing an optical tweezer. The optical trapping force depends on the flow velocity that is associated with the dimensions of the microchannel. We observe a linear dependence of the trapping efficiency and of the fluid flow velocity, with the channel dimensions. We determined that the highest trapping efficiency was achieved for microchannels with aspect ratio equal to one. Numerical simulation validated the impact of the device design dimensions on the trapping efficiency. This investigation indicates that the geometrical characteristics, the flow velocity, and trapping efficiency are crucial and should be considered when fabricating microfluidic devices for cell studies.

Microoptics: Multifurcate Assembly of Slanted Micropillars Fabricated by Superposition of Optical Vortices and Application in High‐Efficiency Trapping Microparticles (Adv. Funct. Mater. 45/2017)

Microoptics: Multifurcate Assembly of Slanted Micropillars Fabricated by Superposition of Optical Vortices and Application in High‐Efficiency Trapping Microparticles (Adv. Funct. Mater. 45/2017)

Infrared ion spectroscopy inside a mass-selective cryogenic 2D linear ion trap.

We demonstrate operation of the first cryogenic 2D linear ion trap (LIT) with mass-selective capabilities. This trap presents a number of advantages for infrared ion "action" spectroscopy studies, particularly those employing the "tagging/messenger" spectroscopy approach. The high trapping efficiencies, trapping capacities, and low detection limits make 2D LITs a highly suitable choice for low-concentration analytes from scarce biological samples. In our trap, ions can be cooled down to cryogenic temperatures to achieve higher-resolution infrared spectra, and individual ions can be mass selected prior to irradiation for a background-free photodissociation scheme. Conveniently, multiple tagged analyte ions can be mass isolated and efficiently irradiated in the same experiment, allowing their infrared spectra to be recorded in parallel. This multiplexed approach is critical in terms of increasing the duty cycle of infrared ion spectroscopy, which is currently a key weakness of the technique. The compact design of this instrument, coupled with powerful mass selection capabilities, set the stage for making cryogenic infrared ion spectroscopy viable as a bioanalytical tool in small molecule identification.

Gas exchange processes of a small HCCI free piston engine – A computational study

Free Piston Linear Alternator engines (FPLAs) can be used for efficient electric power generation because they can provide high mechanical efficiencies due to low friction. Combining the free piston architecture with Homogeneous Charge Compression Ignition (HCCI) can enable combustion of dilute fuel–air mixtures with high thermal efficiency. However, trapping losses can be a major source of unburned hydrocarbon emissions and combustion inefficiency in two-stroke engines. Therefore, controlling the gas exchange process of an HCCI FPLA is critical for delivering fresh charge in the combustion chamber, retaining high levels of residual gas, and minimizing trapping losses. In the current study, Computational Fluid Dynamics (CFD) are utilized to model the gas exchange process and investigate the underlying phenomena behind trapping losses in a loop-scavenged FPLA. The effects of engine design parameters such as air box compression ratio, port target point, location, and inclination angle on scavenging and trapping efficiency were investigated. The results indicated that a moderate air box compression ratio (1.2:1) combined with high inclination angles of the scavenge ports can result in acceptable scavenging efficiency for HCCI combustion (∼35%) and very high trapping efficiency (>98%). The ability to predict the gas exchange process in consecutive cycles was also investigated. A repeatable gas exchange process over 10 cycles was simulated with the coefficients of variance (COVs) of trapped mass and effective equivalence ratio (φ′) being lower than 3%. Gross indicated efficiency of 38.1% was calculated with acceptable pressure rise rate.

Abstract B26: Development of a proximity ligation assay for the detection of PARP-1 trapped to chromatin

Abstract Background: PARP inhibitors (PARPi) have been under clinical investigation as anti-cancer therapies both as monotherapy and in combination. The two basic mechanisms underlying PARP inhibitor activity are catalytic inhibition and PARP-1 trapping. PARPi trap PARP-1 onto base excision repair intermediates, contributing to potentiation of DNA damage by alkylating agents. The role of PARP-1 trapping with regard to efficacy and tolerability in the clinic is still under investigation. All PARPis are capable of PARP-1 trapping; however, different clinical-stage PARPi trap with dramatically different efficiencies. High efficiency trapping agents trap at doses similar to those required for catalytic inhibition while low efficiency trapping agents trap only at doses much higher than those required for inhibition. Being able to image trapped PARP-1 complexes in the cellular context would be beneficial for identifying other proteins associated with these complexes and may have clinical application in the detection of trapped PARP in tumor biopsies. To date, detection of PARP-1 complexes has been limited to low through-put, techniques that disrupt cellular architecture and lack the sensitivity to detect PARP-1 trapping in the absence of supraphysiologic doses of alkylating agents. More sensitive methods for quantifying trapped PARP1 complexes with spatial resolution are needed to enable further understanding of PARP-1 trapping in cancer and normal cells. The objective of this study was to develop an assay capable of identifying cellular PARP-1 trapped to chromatin with enhanced sensitivity and higher assay throughput. Methods: Duolink is a 96-well plate adaptable system that uses a proprietary antibody/oligonucleotide conjugate that, when localized within 40 angstroms, will anneal, amplify and hybridize to generate a quantitative proximity ligation assay (PLA) signal. To develop a Duolink trapping assay, antibodies to PARP-1, histone H2A.X and phosphorylated (Ser139) H2A.X were identified and optimized for labeling concentrations, endogenous target protein recognition and suitability for high content imaging. Duolink PLA was performed per the manufacturer's protocol. Automated image acquisition by Cell Insight and data analysis were performed using Cellomics View Software. PARP1 trapping was also evaluated by cellular fractionation and Western blot. Results: Binding to chromatin places PARP-1 in close proximity to histone H2A.X, presumably within the distance required for successful Duolink oligonucleotide annealing and amplification reactions. Co-treating cells with alkylating agents and PARPi induces a significant increase in phosphorylation of H2A.X (Ser139) as well as trapped PARP1 complexes. Comparative analysis of Western blot and PLA signals in HeyA8 cells treated with different PARPi/alkylating agent combinations revealed positive rank-order correlation in trapping activity. Resolution of in vitro single agent PARP-1 trapping by Western blot has been elusive but PLA detection of single agent PARP1 trapping was observed. Conclusion: The PLA trapping assay provides an improved methodology for evaluation of endogenous PARP-1 complexes bound to chromatin and may have utility for clinical tissue specimens where detection of PARP-1 trapping may lead to insights regarding efficacy and tolerability of PARP inhibitors. Disclosures: All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication. Citation Format: Todd Hopkins, Barrett Ainsworth, Vivek Abraham, David Maag, Eric Johnson, Julie Wilsbacher. Development of a proximity ligation assay for the detection of PARP-1 trapped to chromatin [abstract]. In: Proceedings of the AACR Special Conference on DNA Repair: Tumor Development and Therapeutic Response; 2016 Nov 2-5; Montreal, QC, Canada. Philadelphia (PA): AACR; Mol Cancer Res 2017;15(4_Suppl):Abstract nr B26.

Twinborn TiO2–TiN heterostructures enabling smooth trapping–diffusion–conversion of polysulfides towards ultralong life lithium–sulfur batteries

Twinborn TiO2–TiN heterostructures enable smooth trapping–diffusion–conversion of polysulfides and produce ultralong life lithium–sulfur batteries.

Optical Trapping of Plasmonic Mesocapsules: Enhanced Optical Forces and SERS

We demonstrate optical trapping of plasmonic silica-gold mesocapsules and their use as local SERS probes in Raman tweezers. These novel hybrid dielectric-metal particles, designed for optoplasmonic applications, are mesoscopic porous silica shells embedding gold nanospheres in their inner wall. We observe a high trapping efficiency due to plasmon-enhanced optical trapping of the gold component. Furthermore, we develop an accurate model of optical trapping of this hybrid system in the T-matrix framework studying how the plasmon-enhanced optical forces scale with gold nanoparticle number in the mesocapsule. The relevance of effective optical trapping in hollow plasmonic mesocapsules is twofold for detection and delivery technologies: positioning and activation processes. In fact, the presented system allows for the opportunity to drag and locate cargo mesocapsules embedded with specific molecules that can be activated and released in situ when a precise localization is required.

High photochemical trapping efficiency in Photosystem I from the red clade algae Chromera velia and Phaeodactylum tricornutum

In the present work, we report the first comparative spectroscopic investigation between Photosystem I (PSI) complexes isolated from two red clade algae. Excitation energy transfer was measured in PSI from Chromera velia, an alga possessing a split PsaA protein, and from the model diatom Phaeodactylum tricornutum. In both cases, the estimated effective photochemical trapping time was in the 15–25ps range, i.e. twice as fast as higher plants. In contrast to green phototrophs, the trapping time was rather constant across the whole emission spectrum. The weak wavelength dependence was attributed to the limited presence of long-wavelength emitting chlorophylls, as verified by low temperature spectroscopy. As the trapping kinetics of C. velia PSI were barely distinguishable from those of P. tricornutum PSI, it was concluded that the scission of PsaA protein had no significant impact on the overall PSI functionality. In conclusion, the two red clade algae analysed here, carried amongst the most efficient charge separation so far reported for isolated Photosystems.

Conservation of core complex subunits shaped the structure and function of photosystem I in the secondary endosymbiont alga Nannochloropsis gaditana.

Summary Photosystem I (PSI) is a pigment protein complex catalyzing the light‐driven electron transport from plastocyanin to ferredoxin in oxygenic photosynthetic organisms. Several PSI subunits are highly conserved in cyanobacteria, algae and plants, whereas others are distributed differentially in the various organisms.Here we characterized the structural and functional properties of PSI purified from the heterokont alga Nannochloropsis gaditana, showing that it is organized as a supercomplex including a core complex and an outer antenna, as in plants and other eukaryotic algae.Differently from all known organisms, the N. gaditana PSI supercomplex contains five peripheral antenna proteins, identified by proteome analysis as type‐R light‐harvesting complexes (LHCr4‐8). Two antenna subunits are bound in a conserved position, as in PSI in plants, whereas three additional antennae are associated with the core on the other side. This peculiar antenna association correlates with the presence of PsaF/J and the absence of PsaH, G and K in the N. gaditana genome and proteome.Excitation energy transfer in the supercomplex is highly efficient, leading to a very high trapping efficiency as observed in all other PSI eukaryotes, showing that although the supramolecular organization of PSI changed during evolution, fundamental functional properties such as trapping efficiency were maintained.

Development of an advanced microfluidic micropipette aspiration device for single cell mechanics studies.

Various micro-engineered tools or platforms have been developed recently for cell mechanics studies based on acoustic, magnetic, and optical actuations. Compared with other techniques for single cell manipulations, microfluidics has the advantages with simple working principles and device implementations. In this work, we develop a multi-layer microfluidic pipette aspiration device integrated with pneumatically actuated microfluidic control valves. This configuration enables decoupling of cell trapping and aspiration, and hence causes less mechanical perturbation on trapped single cells before aspiration. A high trapping efficiency is achieved by the microfluidic channel design based on fluid resistance model and deterministic microfluidics. Compared to conventional micropipette aspiration, the suction pressure applied on the aspirating cells is highly stable due to the viscous nature of low Reynolds number flow. As a proof-of-concept of this novel microfluidic technology, we built a microfluidic pipette aspiration device with 2 × 13 trapping arrays and used this device to measure the stiffness of a human breast cancer cell line, MDA-MB-231, through the observation of cell deformations during aspiration. As a comparison, we studied the effect of Taxol, a FDA-approved anticancer drug on single cancer cell stiffness. We found that cancer cells treated with Taxol were less deformable with a higher Young's modulus. The multi-layer microfluidic pipette aspiration device is a scalable technology for single cell mechanophenotyping studies and drug discovery applications.

Room-temperature mid-infrared photodetector in all-carbon graphene nanoribbon-C_60 hybrid nanostructure

Graphene has emerged as a promising candidate for optoelectronic applications due to its broadband absorption and ultrafast carrier mobility. However, its prominent disadvantages, i.e., the zero bandgap and ultrafast carrier lifetime, limit its usage in optoelectronic applications. Although patterning graphene into nanoribbons is an effective strategy to open a bandgap, it still remains a challenge to reduce the surface and edge scattering and recombination of the photoexcited carriers. Here, we fabricated an all-carbon graphene nanoribbon-C60 hybrid nanostructure that is able to achieve a high photoresponsivity of 0.4 A/W under mid-infrared laser illumination at room temperature. Such a high performance is achieved through the high electron trapping efficiency of the C60 film as deposited onto 10 nm wide graphene nanoribbons. This all-carbon hybrid photodetector paves the way toward achieving flexible and broadband photodetectors for various applications such as imaging, remote optical sensing, and infrared camera sensors.