articles+ search results

chemical analysis, equipment design, mass spectrometry, and equipment performance

A fast and straightforward method to prototype microfluidic chip systems for dead-volume-free hyphenation to electrospray-ionisation mass spectrometry is presented. The developed approach based on liquid-phase lithography provides an inexpensive and reliable access to microfluidic chips for MS coupling which can be manufactured in any laboratory with low technical demands. The rapid prototyping approach enables the seamless integration of capillaries serving as electrospray emitters with negligible dead volume. The high versatility of the presented prototyping method and the applicability of a variety of chip-based devices in different fields of lab-on-a-chip technology are established for analytical separations by means of chip-electrochromatography–MS and for continuous-flow synthesis using microreactor technology with MS detection.

rapid prototyping, agriculture safety and health, job training program development, Education, PROGRAMMES, PROGRAMME, and PROGRAMAS

Summary(En)
8 tables
13ill., 28 ref.
The purpose of this study was to develop a job training program that can deliver knowledge and skill necessary for agricultural safety and health manager. A new program development model applying rapid prototyping(RP) approach to the basic ISD model was established to develop the program. Then, a textbook for learners, a manual for instructors, additional learning material were produced based on the model. The major conclusions of this study were as follows. First, this study suggested a new type of program development model that combines RP model and linear ISD model that can apply opinion of participants to compensate the defect of traditional ISD model. Second, the material was developed by applying opinion of stakeholders of program development. By developing a prototype, interim finding, the users could evaluate it at first hand. Therefore, the materials contain the content knowledge, skill, tools(KST) that agriculture safety and health managers need when they perform the job. Also various types of activities were developed so that can the learners can apply the learned contents to the job. Third, the instructors' manual and supplementary material was developed based on learners' text book. The instructors' manual is a guidance that contains the details such as learning contents, procedure and methods so that standard lectures could be delivered regardless of who teaches. Also, supplementary material is the material contains intensified knowledge and skill related to the contents of learners' textbook, so that the instructors can check them with ease.

extracellular matrix, umbilical cord, stem cells, biomimetics, phenotype, and blood

OBJECTIVE: To investigate the expansion of hematopoietic stem/progenitor cells (HSPCs) from umbilical cord blood using extracellular matrix (ECM) protein-coated three-dimensional hierarchical scaffolds. RESULTS: The expansion of HSPCs was evaluated through total nucleated cell (TNC) expansion, immuno-phenotypic analysis, and clonogenic ability. After 7 days of culture, three-dimensional cultures with fibronectin-coated scaffolds achieved the highest fold increase in TNCs (164 ± 6.9 fold) and the highest CD45⁺CD34⁺ (35 %) and CD34⁺CD38⁻ (32 %) ratios. CONCLUSION: Three-dimensional hierarchical scaffolds were coated with ECM protein to simulate a biomimetic environment or niche, and had a significant effect on the expansion potential of HSPCs without changing their phenotype.

Chemically functionalized carbon nanotubes (CNTs) are promising materials for sensing of gases and volatile organic compounds. However, the poor solubility of carbon nanotubes hinders their chemical functionalization and the subsequent integration of these materials into devices. This manuscript describes a solvent-free procedure for rapid prototyping of selective chemiresistors from CNTs and graphite on the surface of paper. This procedure enables fabrication of functional gas sensors from commercially available starting materials in less than 15 min. The first step of this procedure involves the generation of solid composites of CNTs or graphite with small molecule selectors—designed to interact with specific classes of gaseous analytes—by solvent-free mechanical mixing in a ball mill and subsequent compression. The second step involves deposition of chemiresistive sensors by mechanical abrasion of these solid composites onto the surface of paper. Parallel fabrication of multiple chemiresistors from diverse composites rapidly generates cross-reactive arrays capable of sensing and differentiating gases and volatile organic compounds at part-per-million and part-per-thousand concentrations.

Vacuum packer, Modeling, Simulation, Functional virtual prototyping, 기능적 가상 시작기, 자동 쌀 진공포장기, 모델링, 시뮬레이션, Agricultural machinery and equipment, SIMULATION, and SIMULACION

Summary(En)
2 tables
17ill., 12 ref.
A reduced 3D functional virtual prototype of a vacuum packer was developed and simulated for designing the rotational motions of the driving motors and predicting the power requirements of the motors used to drive the three units of the vacuum packer. The motion control functions for the driving motors were properly designed to fulfill the operating requirements. The predicted power requirements of motors used to drive the pressing board unit, taping, and vibrating board units were 100 W, 25 W, and 90 W, respectively. The kinematic analysis for the important components of the vacuum packer, the pressing board and tape holder, were conducted for improving the packing quality of the automatic vacuum packer.

Agricultural engineering, MECHANICAL SYSTEM, VIRTUAL PROTOTYPING, KINEMATICS, DYNAMICS, SIMULATION, CINEMATIQUE, CINEMATICA, and SIMULACION

Summaries (En, Zh)

biological development, biodegradability, mechanical properties, cutting, stainless steel, and annealing

Biodegradable stents are considered to be a recent innovation, and their feasibility and applicability have been proven in recent years. Research in this area has focused on materials development and biological studies, rather than on how to transform the developed biodegradable materials into the stent itself. Currently available stent technology, the laser cutting-based process, might be adapted to fabricate biodegradable stents. In this work, the fabrication, characterization and testing of biodegradable Fe–Mn stents are described. A standard process for fabricating and testing stainless steel 316L stents was referred to. The influence of process parameters on the physical, metallurgical and mechanical properties of the stents, and the quality of the produced stents, were investigated. It was found that some steps of the standard process such as laser cutting can be directly applied, but changes to parameters are needed for annealing, and alternatives are needed to replace electropolishing.

models, geographic information systems, and encapsulation

The sharing of geographical analysis models is of crucial importance for simulating geographic processes and phenomena in the current geographical information systems (e.g. Digital Earth), but there remain some issues that have not been completely resolved. The challenges include, eliminating model heterogeneity and searching for suitable infrastructures to support the open sharing and effective execution of models. Taking advantage of cloud computing, this article aims to address the above issues and develop an open environment for geographical analysis model sharing. On the basis of the analysis of the applicability of cloud computing, the architecture of the open environment is proposed. More importantly, key strategies designed for heterogeneous model description, model encapsulating as well as model deploying and transparent accessing in the cloud are discussed in detail to establish such an environment. Finally, the prototype environment is implemented, and experiments were conducted to verify the environment's feasibility to support the sharing of geographical analysis models.

Fusarium wilt, growers, shade trees, prototypes, quarantine, scientists, nitrogen, labor, nutrients, nutrition, pruning, sales, bananas, farms, income, cultivars, prices, intercropping, pseudostems, and mixed cropping

Paper presented at the International Symposium on Bananas and Plantains: Towards Sustainable Global Production and Improved Use, held October 10-14, 2011, Salvador (Bahia), Brazil. Includes references
Bananas are often grown in mixed cropping systems. In Latin America, small growers cultivate bananas with minimal labor and purchased inputs in shaded coffee as a source of monthly income to supplement annual coffee sales. We deployed the framework of agroecological intensification in collaboration with six groups of small coffee growers in Costa Rica, Honduras, Nicaragua and Peru to assess the potential to improve the productivity of banana in mixed systems. After a formal diagnostic study of 30 smallholder coffee farms in each site carried out by scientists, farmer experimentation groups in the same sites did their own diagnostic sampling and identified priority areas for experimentation. Scientists and farmers developed prototypes for system improvement, and alternative management approaches of system components, labor and inputs. Across pilot zones, ‘Gros Michel’ was the most common cultivar, with banana mat density from 300 to 600 mats/ha with 950 to 1200 pseudostems/ha. Tree density varied from 150 to 550 trees/ha with available light ranging from 50 to 70%, and from 35 to 45% for banana and coffee. Farmer priorities across zones were similar: tree, banana and coffee resource partitioning; improved nutrition; coffee pruning; Fusarium wilt management; and marketing for better banana prices. Prototypes for testing addressed: light partitioning among trees, bananas and coffee; an input-output analysis of nutrients to increase the contribution of nitrogen from shade trees and reorient purchased nutrients; a shifting framework of Fusarium wilt management to address quarantine and cultivar substitution; and a marginal return analysis for step-wise intensification of the system, including banana.

manufacturing, foaming, microstructure, ceramics, cell structures, silicon, polymers, and methodology

Rapid prototyping techniques such as stereolithography and selective laser curing have been utilized to produce preceramic articles to be further pyrolyzed and infiltrated with molten silicon. Recently they were also used for near to net shape cellular Si–SiC manufacturing. In this study we propose a hybrid methodology that can realize cellular ceramic structures of any shape by combining 3D printing of polymer inks with replication. This hybrid method overcomes the surface finish limitations of the current RP techniques by manufacturing cellular structures with a fine microstructure and an engineered cavity. RP structures showed higher compression strengths then foams both produced with the same replication technique.

blood serum, electrodes, computer software, cattle, polymers, methodology, and carbon dioxide

We report a fast and simple prototyping method to fabricate polymer-based microfluidic chips using Direct Laser Plotting (DLP) technique, by which various functional micro-structures can be realized within minutes, in a mask-free and out-of-cleanroom fashion. A 2D Computer-Aid-Design (CAD) software was employed to layout the required micro-structures and micro-channels, a CO₂ laser plotter was then used to construct the microstructures. The desired patterns can be plotted directly on PDMS substrates and bio-compatible polymer films by manipulating the strength and density of laser pulses. With the DLP technique, chip-embedded micro-electrodes, micro-mixers and 3D microfluidic chips with 5 layers, which normally require several days of work in a cleanroom facility, can be fabricated in minutes in common laboratory. This novel method can produce microfluidic channels with average feature size of 100μm, while feature size of 50μm or smaller is achievable by making use of the interference effect from laser impulsion. In this report, we present the optimized parameters for successful fabrication of 3D microchannels, micro-mixers and microfluidic chips for protein concentration measurements (Bovine Serum Albumine (BSA) test), and a novel procedure to pattern flexible embedding electrodes on PDMS-based microfluidic chips. DLP offers a convenient and low cost alternative to conventional microfluidic channel fabrication technique which relies on complicated and hazardous soft lithography process.

groundwater, estuaries, computer software, oxygen, biogeochemistry, sediments, lakes, streams, adsorption, rivers, aquatic ecosystems, and environmental models

The concentrations of many natural compounds are altered by chemical and biological transformations, and physical processes such as adsorption and transport. Their fate can be predicted using reactive transport models that describe reaction and advective and dispersive movement of these components in their natural environment. Recently a number of software packages have been implemented in the open source software R that allow one to implement reactive transport models. Central to this is the ReacTran R-package, a comprehensive collection of functions for modeling reactive components that may be distributed over multiple phases, whose dynamics are coupled through biological and geochemical reactions, and that are transported in one-, two- or three-dimensional domains with simple geometries. Dedicated solution methods are in R-packages deSolve and rootSolve. The modeling packages facilitate the simulation of reaction and transport of components for spatial scales ranging from micrometers to kilometers and spanning multiple time-scales. As they are influenced in similar ways, the same functions can solve biogeochemical models of the sediment, groundwater, rivers, estuaries, lakes or water columns, experimental setups, or even describe reaction and transport within flat, cylindrical or spherical bodies, such as organisms, aggregates, or the dispersion of individuals on flat surfaces and so on. We illustrate the use of R for reactive transport modeling by three applications spanning several orders of magnitude with respect to spatial and temporal scales. They comprise (1) a model of an experimental flow-through sediment reactor, where fitting so-called breakthrough curves are used to derive sulfate reduction rates in an estuarine sediment, (2) a conservative and reactive tracer addition experiment in a small stream, which implements the concept of river spiraling, and (3) a 2-D and 3-D model that describes oxygen dynamics in the upper layers of the sediment, interspersed with several hotspots of increased reaction intensities. The packages ReacTran, deSolve and rootSolve are implemented in the software R and thus available for all popular platforms (Linux, Windows, Mac). Models implemented using this software are short and easily readable, yet they are efficiently solved. This makes R extremely well suited for rapid model prototyping.

melting, graphene, glass transition temperature, glass, cooling, crystallization, cytotoxicity, cultured cells, chemical composition, and carbon dioxide

Three-dimensional bioactive glass implants were produced by rapid prototyping based on laser cladding without using moulds. CO₂ laser radiation was employed to melt 45S5 and S520 bioactive glass particles and to deposit the material layer by layer following a desired geometry. Controlled thermal input and cooling rate by fine tuning of the processing parameters allowed the production of crack-free fully dense implants. Microstructural characterization revealed chemical composition stability, but crystallization during processing was extensive when 45S5 bioactive glass was used. Improved results were obtained using the S520 bioactive glass, which showed limited surface crystallization due to an expanded sintering window (the difference between the glass transition temperature and crystallization onset temperature). Ion release from the S520 implants in Tris buffer was similar to that of amorphous 45S5 bioactive glass prepared by casting in graphite moulds. Laser processed S520 scaffolds were not cytotoxic in vitro when osteoblast-like MC3T3-E1 cells were cultured with the dissolution products of the glasses; and the MC3T3-E1 cells attached and spread well when cultured on the surface of the materials.

Includes references
Dynamic miniaturized human multi-micro-organ bioreactor systems are envisaged as a possible solution for the embarrassing gap of predictive substance testing prior to human exposure. A rational approach was applied to simulate and design dynamic long-term cultures of the smallest possible functional human organ units, human “micro-organoids”, on a chip the shape of a microscope slide. Each chip contains six identical dynamic micro-bioreactors with three different micro-organoid culture segments each, a feed supply and waste reservoirs. A liver, a brain cortex and a bone marrow micro-organoid segment were designed into each bioreactor. This design was translated into a multi-layer chip prototype and a routine manufacturing procedure was established. The first series of microscopable, chemically resistant and sterilizable chip prototypes was tested for matrix compatibility and primary cell culture suitability. Sterility and long-term human cell survival could be shown. Optimizing the applied design approach and prototyping tools resulted in a time period of only 3 months for a single design and prototyping cycle. This rapid prototyping scheme now allows for fast adjustment or redesign of inaccurate architectures. The designed chip platform is thus ready to be evaluated for the establishment and maintenance of the human liver, brain cortex and bone marrow micro-organoids in a systemic microenvironment.

Includes references
Hsp90 is an ATP-dependent molecular chaperone that regulates key signaling proteins and thereby impacts cell growth and development. Chaperone cycle of Hsp90 is regulated by ATP binding and hydrolysis through its intrinsic ATPase activities, which is in turn modulated by interaction with its co-chaperones. Hsp90 ATPase activity varies in different organisms and is known to be increased in tumor cells. In this study we have quantitatively analyzed the impact of increasing Hsp90 ATPase activity on the activities of its clients through a virtual prototyping technology, which comprises a dynamic model of Hsp90 interaction with clients involved in proliferation pathways. Our studies highlight the importance of increased ATPase activity of Hsp90 in cancer cells as the key modulator for increased proliferation and survival. A tenfold increase in ATPase activity of Hsp90 often seen in cancer cells increases the levels of active client proteins such as Akt-1, Raf-1 and Cyclin D1 amongst others to about 12-, 8- and 186-folds respectively. Additionally we studied the effect of a competitive inhibitor of Hsp90 activity on the reduction in the client protein levels. Virtual prototyping experiments corroborate with findings that the drug has almost 10- to 100-fold higher affinity as indicated by a lower IC₅₀ value (30-100 nM) in tumor cells with higher ATPase activity. The results also indicate a 15- to 25-fold higher efficacy of the inhibitor in reducing client levels in tumor cells. This analysis provides mechanistic insights into the links between increased Hsp90 ATPase activity, tumor phenotype and the hypersensitivity of tumor Hsp90 to inhibition by ATP analogs.