Prolonged Processing Time Research Articles

Low-Temperature-Processing of Printed Cathodes for Aqueous Metal-Air Batteries

Developing low cost energy storage for integrated electronic applications depends on the ability to increase energy densities while reducing materials and manufacturing costs. Metal-air batteries are an emerging solution for next-generation energy storage given their superior theoretical energy storage capacity and use of low cost, earth abundant, and lightweight anode materials such as Zn, Al, and Mg. While metal-air batteries offer significant promise, inefficiencies at the air cathode dominate cell performance and limit practical energy densities. Recent studies in metal-air batteries have introduced new electrocatalysts to improve cathodic efficiency, but often rely on elevated temperatures and prolonged processing times to achieve suitable performance. Thus, rapid synthesis of air cathodes at low temperatures remains a significant challenge for mass production of metal-air batteries. In this work, we establish a printed air cathode architecture that can be fabricated below 100 °C, broadening the potential applications for metal-air batteries by lowering overall manufacturing costs and improving process compatibility for integrated systems. Furthermore, we investigate the importance of binder, solvent, and catalyst interactions and their influence on air cathode performance in a primary Zn-air battery. Additive manufacturing is used to demonstrate high throughput deposition and high accuracy patterning of metal-air battery materials. Stencil printing is chosen as a proof of concept technique to assemble the air cathode and Zn-air battery. Analogous to screen printing, stencil printing is capable of achieving thick active layers (10s-100s µm) for high capacity electrodes and is compatible with a variety of substrates including silicon wafers and flexible plastics. Cathode inks using polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE) were compared to study the effects of the binder and associated solvent on the oxygen reduction reaction (ORR) as a function of processing temperature. Using a commercially available carbon powder with a platinum catalyst, cathodic half-cells were constructed to measure cell impedance and ORR overpotential as a function of binder material and annealing temperature. Thermogravimetric analysis (TGA) and x-ray photoelectron spectroscopy (XPS) were used to identify compositional changes, in both the cathode inks and printed films, related to solvent evaporation and binder degradation during annealing. Moreover, in operando pressure decay and differential electrochemical mass spectroscopy (DEMS) measurements were conducted to determine ORR efficiencies for the printed cathodes. After characterizing the printed air cathodes, printed Zn-air full-cells were fabricated to demonstrate the dependence of cell performance on binder type and annealing temperature. Higher operating voltages at a given current density were observed in cells with the PTFE binder compared to the PVDF binder, with the PTFE cells maintaining operating voltages above 1 V at current densities up to 24 mA cm-2. As a result, the PTFE cells exhibited peak power densities between 25-30 mW cm-2 at annealing temperatures as low as 80 °C, compared to 12 mW cm-2 at 350 °C for the PVDF cells. PTFE cells also displayed internal resistances less than 50 Ω with areal capacities between 2-5 mAh cm-2 with platinum concentrations as low as 5 wt%. This work represents the first demonstration of a low temperature printed air cathode for metal-air batteries. Our printed cathodes are broadly applicable to other aqueous metal-air battery systems and present a novel solution to fabricating low cost, high energy density batteries. The cathode inks are also compatible with several high throughput patterning techniques, including screen printing and slot-die coating, and could help achieve greater penetration of energy storage in emerging applications such as wearable and flexible electronics.

Performance Enhancement of GaN-Based Light-Emitting Diodes with Magnesium Nitride Inter-Layers

High quality GaN epilayers were obtained by using a magnesium nitride (MgxNy) inter-layer. X-ray photoelectron spectroscopy (XPS) reveals Mg 2p core-level spectra from the MgxNy inter-layers. The roughness of the MgxNy layers increased with the growth time, though a prolonged processing time resulted in a decrease in the roughness. A high-resolution X-ray diffraction ω-scan rocking curve was used to reveal that the screw dislocation density (TDD) of GaN with an MgxNy inter-layer was reduced and the crystalline quality of the GaN epitaxial layer was enhanced. Furthermore, the luminous efficiency of an LED with the MgxNy layers was increased by 20 % relative to a reference LED. Figure 1

The Synthesis of the Core/Shell Structured Diamond/Akageneite Hybrid Particles with Enhanced Polishing Performance.

In this study, the synthesis of the core/shell structured diamond/akageneite hybrid particles was performed through one-step isothermal hydrolyzing. The hybrid particle was characterized by X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectra. The test results overall reveal that the akageneite coating, phase β-FeO(OH), was uniformly coated onto the diamond surface. The polishing performance of the pristine diamond and hybrid particles for the sapphire substrate was evaluated respectively. The experimental results show that the hybrid particles exhibited improved polishing quality and prolonged effective processing time of polishing pad compared with diamond particles without compromising the material remove rate and surface roughness. The improved polishing behavior might be attributed to the β-FeOOH coating, which is conducive to less abrasive shedding and reducing the scratch depth.

Temporal processing deficit leads to impaired multisensory binding in schizophrenia

ABSTRACTIntroduction: Schizophrenia has been characterised by neurodevelopmental dysconnectivity resulting in cognitive and perceptual dysmetria. Hence patients with schizophrenia may be impaired to detect the temporal relationship between stimuli in different sensory modalities. However, only a few studies described deficit in perception of temporally asynchronous multisensory stimuli in schizophrenia.Methods: We examined the perceptual bias and the processing time of synchronous and delayed sounds in the streaming–bouncing illusion in 16 patients with schizophrenia and a matched control group of 18 participants.Results: Equal for patients and controls, the synchronous sound biased the percept of two moving squares towards bouncing as opposed to the more frequent streaming percept in the condition without sound. In healthy controls, a delay of the sound presentation significantly reduced the bias and led to prolonged processing time whereas patients with schizophrenia did not differentiate between this condition and the condition with synchronous sound.Conclusion: Schizophrenia leads to a prolonged window of simultaneity for audiovisual stimuli. Therefore, temporal processing deficit in schizophrenia can lead to hyperintegration of temporally unmatched multisensory stimuli.

High-Rate Etching of Copper By High-Pressure Hydrogen-Based Plasma

The copper wiring technique is a vital manufacturing technology for the current ultra-large-scale integrated (ULSI) circuits. In general, these Cu wiring are fabricated by the dual damascene process. The damascene process is mainly composed of chemical mechanical polishing (CMP) and electrical Cu plating techniques. Although these processes are well-established, these processes are fundamentally demonstrated in a wet environment and require expensive consumables and toxic chemicals. Furthermore, since CMP requires the adequate processing load for the efficient machining, the usage of a low-k material as an interlayer insulator, which has low mechanical strength, requires a prolonged processing time. From above background, it is longed-for that the dry etching process for Cu can replace the conventional wet machining process. In the previous study on the conventional dry etching for Cu, chlorine is often used as the typical etchant gas. The chlorine gas is harmful for humans and aggressive toward many of the metals constructing the etching apparatus. Furthermore, because the chlorinated Cu products exhibit a low vapor pressure around room temperature, substrate heating is generally required. On the other hand, it has been revealed that a hydrogen-based plasma can be applied for Cu dry etching at low temperature. This hydrogen dry etching seems attractive in terms of preserving the environment and suppressing the use of toxic chemicals. If a higher etching rate greater than 100 nm/min can be obtained by pure hydrogen plasma etching, it is expected that a hydrogen dry etching method with no toxic chemicals could be substituted for the CMP process. In this study, therefore, we applied the high-pressure hydrogen glow plasma (>100 Torr) to Cu etching in an attempt to achieve a higher Cu etching rate. In the experiment, a localized hydrogen-based plasma is generated at 100 Torr around the tip of a syringe needle electrode (outer diameter of 1mm). The very-high-frequency (VHF; 150 MHz) power source was used for the plasma generation. The samples used in this study were a 1 mm-thick Cu plate for investigating the Cu etching property, a 0.7 mm-thick Si(001) wafer and 0.7 mm-thick SiO2 glass to compare the etching behavior of Cu with other ULSI construction materials. The sample stage temperature was controlled from −20 to 330°C. The H2 gas was supplied to the plasma directly from the needle bore via a mass flow controller during the etching. In this study, to confirm the role of hydrogen in Cu etching, He, Ar and N2 gases were used as the process gas instead of H2. As a result, the Cu etching occurs only when the process atmosphere contains H2 gas, and the etching rates decrease with diluting the hydrogen concentration by He gas. The impact of plasma heating on the Cu etching is negligible, so the etching mechanism of the high pressure H2 plasma differs from that of the electrospark machining. When the sample stage temperature is varied from −20 to 330°C, the Cu etching rate has no obvious dependence on the stage temperature. On the other hand, the Cu etching rate increases linearly with increasing the input power from 30 W to 100 W. The emission intensity of Balmer α line of H atom observed in optical emission spectrum of the plasma also increases linearly with the input power. The Cu etching rate of 500 nm/min can be achieved around the stage temperature of 0°C. Meanwhile, the etching rates for Si and SiO2 around the stage temperature of 0°C are 100 μm/min and 50 nm/min, respectively. The selectivity of the etching rates for Cu and SiO2 suggests that this etching technique could be applied to Cu wiring on a trenched SiO2 layer. The etched Cu surface morphology is rough and exhibits many round pits and bumps. This surface roughening might be due to excessive hydrogen incorporation in the Cu bulk.

Extraction of Plant-based Capsules for Microencapsulation Applications.

Microcapsules derived from plant-based spores or pollen provide a robust platform for a diverse range of microencapsulation applications. Sporopollenin exine capsules (SECs) are obtained when spores or pollen are processed so as to remove the internal sporoplasmic contents. The resulting hollow microcapsules exhibit a high degree of micromeritic uniformity and retain intricate microstructural features related to the particular plant species. Herein, we demonstrate a streamlined process for the production of SECs from Lycopodium clavatum spores and for the loading of hydrophilic compounds into these SECs. The current SEC isolation procedure has been recently optimized to significantly reduce the processing requirements which are conventionally used in SEC isolation, and to ensure the production of intact microcapsules. Natural L. clavatum spores are defatted with acetone, treated with phosphoric acid, and extensively washed to remove sporoplasmic contents. After acetone defatting, a single processing step using 85% phosphoric acid has been shown to remove all sporoplasmic contents. By limiting the acid processing time to 30 hr, it is possible to isolate clean SECs and avoid SEC fracturing, which has been shown to occur with prolonged processing time. Extensive washing with water, dilute acids, dilute bases, and solvents ensures that all sporoplasmic material and chemical residues are adequately removed. The vacuum loading technique is utilized to load a model protein (Bovine Serum Albumin) as a representative hydrophilic compound. Vacuum loading provides a simple technique to load various compounds without the need for harsh solvents or undesirable chemicals which are often required in other microencapsulation protocols. Based on these isolation and loading protocols, SECs provide a promising material for use in a diverse range of microencapsulation applications, such as, therapeutics, foods, cosmetics, and personal care products.

Potential of carbon particle reinforced polypropylene formed in-situ through the pyrolysis of carboxymethylcellulose

Abstract The potential of reinforcing polypropylene (PP) with carbon particles through an in-situ process is investigated. In this technique 44 µm reinforcement particles are created through pyrolysis of carboxymethylcellulose (CMC) during compounding. CMC is a natural cellulose polymer that decomposes at 270 °C – the processing temperature of PP. CMC was mixed with polypropylene and pyrolysed through successive extrusion compounding cycles, before being injection moulded into samples. This technique results in good dispersion of the carbon particles without any agglomerations, as evidenced by scanning electron microscopy (SEM). Thermogravimetric analyses reveal a carbon content of 4–28 vol% when initially mixing 2.5–25 wt% CMC into the PP matrix. Mechanical testing of the carbon reinforced PP results in an improvement in impact strength by 69%, however, at the cost of a 14% drop in tensile strength, both associated with a weak particle-matrix interface as evidenced by SEM and mathematical modelling of the interface. This, in addition to the prolonged processing time are outcomes calling for the optimisation of the compounding and pyrolysis process in future work. However, this study definitely shows the potential of reinforcing thermoplastic polymers through the pyrolysis of another carbon-rich polymer of low thermal stability.

What we have learned from a decade of ED crowding research.

What we have learned from a decade of ED crowding research.

Finance-based scheduling using meta-heuristics: discrete versus continuous optimization problems

Purpose – The purpose of this paper is to compare the performance of the genetic algorithm (GA), simulate annealing (SA) and shuffled frog-leaping algorithm (SFLA) in solving discrete versus continuous-variable optimization problems of the finance-based scheduling. This involves the minimization of the project duration and consequently the time-related cost components of construction contractors including overheads, finance costs and delay penalties. Design/methodology/approach – The meta-heuristics of the GA, SA and SFLA have been implemented to solve non-deterministic polynomial-time hard (NP-hard) finance-based scheduling problem employing the objective of minimizing the project duration. The traditional problem of generating unfeasible solutions in scheduling problems is adequately tackled in the implementations of the meta-heuristics in this paper. Findings – The obtained results indicated that the SA outperformed the SFLA and GA in terms of the quality of solutions as well as the computational cost based on the small-size networks of 30 activities, whereas it exhibited the least total duration based on the large-size networks of 120 and 210 activities after prolonged processing time. Research limitations/implications – From researchers’ perspective, finance-based scheduling is one of the few domain problems which can be formulated as discrete and continuous-variable optimization problems and, thus, can be used by researchers as a test bed to give more insight into the performance of new developments of meta-heuristics in solving discrete and continuous-variable optimization problems. Practical implications – Finance-based scheduling discrete-variable optimization problem is of high relevance to the practitioners, as it allows schedulers to devise finance-feasible schedules of minimum duration. The minimization of project duration is focal for the minimization of time-related cost components of construction contractors including overheads, finance costs and delay penalties. Moreover, planning for the expedient project completion is a major time-management aspect of construction contractors towards the achievement of the objective of client satisfaction through the expedient delivery of the completed project for clients to start reaping the anticipated benefits. Social implications – Planning for the expedient project completion is a major time-management aspect of construction contractors towards the achievement of the objective of client satisfaction. Originality/value – SFLA represents a relatively recent meta-heuristic that proved to be promising, based on its limited number of applications in the literature. This paper is to implement SFLA to solve the discrete-variable optimization problem of the finance-based scheduling and assess its performance by comparing its results against those of the GA and SA.

Quality Markers Addressing Preanalytical Variations of Blood and Plasma Processing Identified by Broad and Targeted Metabolite Profiling

Metabolomics is a valuable tool with applications in almost all life science areas. There is an increasing awareness of the essential need for high-quality biospecimens in studies applying omics technologies and biomarker research. Tools to detect effects of both blood and plasma processing are a key for assuring reproducible and credible results. We report on the response of the human plasma metabolome to common preanalytical variations in a comprehensive metabolomics analysis to reveal such high-quality markers. Human EDTA blood was subjected to preanalytical variations while being processed to plasma: microclotting, prolonged processing times at different temperatures, hemolysis, and contamination with buffy layer. In a second experiment, EDTA plasma was incubated at different temperatures for up to 16 h. Samples were subjected to GC-MS and liquid chromatography-tandem mass spectrometry-based metabolite profiling (MxP™ Broad Profiling) complemented by targeted methods, i.e., sphingoids (as part of MxP™ Lipids), MxP™ Catecholamines, and MxP™ Eicosanoids. Short-term storage of blood, hemolysis, and short-term storage of noncooled plasma resulted in statistically significant increases of 4% to 19% and decreases of 8% to 12% of the metabolites. Microclotting, contamination of plasma with buffy layer, and short-term storage of cooled plasma were of less impact on the metabolome (0% to 11% of metabolites increased, 0% to 8% decreased). The response of the human plasma metabolome to preanalytical variation demands implementation of thorough quality assurance and QC measures to obtain reproducible and credible results from metabolomics studies. Metabolites identified as sensitive to preanalytics can be used to control for sample quality.

Model-based iterative reconstruction technique for radiation dose reduction in chest CT: comparison with the adaptive statistical iterative reconstruction technique

To prospectively evaluate dose reduction and image quality characteristics of chest CT reconstructed with model-based iterative reconstruction (MBIR) compared with adaptive statistical iterative reconstruction (ASIR). One hundred patients underwent reference-dose and low-dose unenhanced chest CT with 64-row multidetector CT. Images were reconstructed with 50 % ASIR-filtered back projection blending (ASIR50) for reference-dose CT, and with ASIR50 and MBIR for low-dose CT. Two radiologists assessed the images in a blinded manner for subjective image noise, artefacts and diagnostic acceptability. Objective image noise was measured in the lung parenchyma. Data were analysed using the sign test and pair-wise Student's t-test. Compared with reference-dose CT, there was a 79.0 % decrease in dose-length product with low-dose CT. Low-dose MBIR images had significantly lower objective image noise (16.93 ± 3.00) than low-dose ASIR (49.24 ± 9.11, P < 0.01) and reference-dose ASIR images (24.93 ± 4.65, P < 0.01). Low-dose MBIR images were all diagnostically acceptable. Unique features of low-dose MBIR images included motion artefacts and pixellated blotchy appearances, which did not adversely affect diagnostic acceptability. Diagnostically acceptable chest CT images acquired with nearly 80 % less radiation can be obtained using MBIR. MBIR shows greater potential than ASIR for providing diagnostically acceptable low-dose CT images without severely compromising image quality. • Model-based iterative reconstruction (MBIR) creates high-quality low-dose CT images. • MBIR significantly improves image noise and artefacts over adaptive statistical iterative techniques. • MBIR shows greater potential than ASIR for diagnostically acceptable low-dose CT. • The prolonged processing time of MBIR may currently limit its routine use in clinical practice.

Effects of emulsifying salts reduction on imitation cheese manufacture and functional properties

Imitation cheese (48%, 50% and 52% moisture) was manufactured using a Farinograph. The standard emulsifying salts (ES) concentration was 1.4%, giving a casein:ES ratio of 19:12. The effect of ES reduction on cheese manufacture and functionality, assessed by texture profile analysis, heat-induced flowability and dynamic rheology, was studied. Microstructure was investigated by light and cryo-scanning electron microscopy. Reducing ES increased processing time and hardness and decreased flowability and fat globule diameter. In comparison to standard ES, a reduction of up to 20% produced cheeses in reasonable processing times with slightly altered functionality. On further ES reduction, processing times greatly increased giving much harder and less meltable cheeses. Reducing ES by 40% increased processing times ∼3-fold, halved fat globule diameter and flowability and doubled hardness, compared to standard cheeses. At ES reduction above 40% the product obtained, after prolonged processing time, bore little resemblance to cheese.

Hypnotic susceptibility in children with Down's syndrome

AbstractNumerous studies on people with Down's syndrome show that they are able to adapt to simple tasks, have a better ability for language comprehension than for language production, and that their learning difficulties are connected to their particular memory functions as well as to their prolonged information processing time. These characteristics do not, however, highlight elements that suggest non‐receptivity to hypnosis. The present research studied (a) hypnotic response in children with Down's syndrome, and (b) the cognitive variables that can mediate the hypnotic response. The sample included twelve participants, 7 girls and 5 boys, ages ranging from 6 to 17, mean age: 10.4 (SD: 3.83). We used the Stanford Hypnotic Scale for Children, Modified Form (SHCS; Morgan and Hilgard, 1979), and also checked Mnemonic recuperation, Abstraction, Perception and Vocabulary comprehension (using different subscales in WPPSI‐R, K‐ABC and Chevrié Muller, Simon &amp; Decante, 1975). Results show that the children were capable of responding to suggestions under hypnosis; both motor and cognitive. The differences with the pattern of children from the general population are discussed. Copyright © 2009 British Society of Experimental &amp; Clinical Hypnosis. Published by John Wiley &amp; Sons, Ltd.

Thermal detoxification of hazardous metal sludge by applied electromagnetic energy

Industrial wastewater sludge was treated by microwave processes to enhance the stabilization of laden copper. The effects of additives, processing time, microwave adsorbents, moisture content, reaction atmosphere, and cooling gas were investigated. The stabilization results were significantly enhanced by metal powder additives, prolonged microwave processing time, proper moisture content, the addition of carbonaceous materials, and a reaction environment with inert gas. It was also found that the moisture content would increase the homogeneity of applied microwave energy, and thus achieve a better overall efficiency between stabilizing agents and copper. The added metal powders may reduce Cu(II) to Cu(0) in the sludge or TCLP. The resulting thermal energy of microwave radiation, and microarcing process and the oxidation heat of Al powder may also assist the transformation of Cu(II) into CuO and CuAl 2O 4 phases. Part of the sludge was vitrified within inert gas environment when the processing time was longer than 18 min and active carbon dosage was more than 3 g. Reduction reactions also occurred in the hybrid microwave processes, leading to the reduction of sulfates and metal ions, and the formation of Cu 2S and FeS. Moreover, the microwave radiation can also enhance the feasibility of co-treating of inorganic and organic solid waste.

Model reaction system에서 가열조건이 acrylamide 및 기타 화합물들의 생성에 미치는 영향

아크릴아마이드의 형성과정에서 가열조건이 아크릴아마이드의 생성량과 아크릴아마이드 형성에 관여 또는 동반 생성하는 화합물을 조사하기 위하여, 아스파라긴과 포도당의 등량 혼합물을 125, 150, 175 및 <TEX>$200^{\circ}C$</TEX>에서 각각 10, 20 및 30 분간 가열하는 모델반응을 이용하였다. 가열한 반응물을 ethyl acetate 및 methanol 2종의 용매로 달리 추출하고 FFAP capillary column과 HP-5MS 5% phenyl methyl siloxane column으로 GC/MS에서 분석한 결과, 아크릴아마이드는 methanol추출물을 FFAP capillary column으로 분석한 결과에서 retention time 23.53분에서 검출되었고 최저검출한계는 4 ng 이었다. 아크릴아마이드 생성량은 <TEX>$175^{\circ}C$</TEX>보다. 낮은 125 및 <TEX>$150^{\circ}C$</TEX>에서는 온도와 가열시간을 증가시킬수록 점차 증가하여, <TEX>$175^{\circ}C$</TEX>에서 10분간 처리하였을 때 최대량인 <TEX>$116{\mu}g/g$</TEX>을 생성하였지만 175 및 <TEX>$200^{\circ}C$</TEX>에서는 온도 및 가열시간을 증가시킬수록 감소하는 결과를 나타내었다. 아크릴아마이드이외 반응생성물들로서, 1,3-dihydroxypropanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyrane-4-one 및 5-hydroxymethylfurfural이 다량으로 검출되었으며, 또 다른 화합물인 5-methylfurfural, 2-acetylpyrrole 및 N,N-dimethylcyclohexamine 등은 소량 생성되었음을 확인하였다. The Formation of acrylamide was studied in Maillard model reaction systems based on asparagine-glucose. The mixture of asparagine and glucose in equal molar ratio, and then heated at 125, 150, 175 and <TEX>$200^{\circ}C$</TEX> for 10, 20 and 30 minute, respectively. The reaction products were extracted with ethyl acetate and methanol, and then isolated and detected on FFAP capillary column and HP-5MS 5% phenyl methyl siloxane column by using GC/MS. Acrylamide was detected only from methanol extracts and on FFAP capillary column, at retention time 23.53 min., and the detection limit was 4.6 ng. Acrylamide content mainly increased with increasing temperature and processing time till <TEX>$175^{\circ}C$</TEX>, therefore, maximal acrylamide formation occurred at <TEX>$175^{\circ}C$</TEX> for 10 minute (<TEX>$116{\mu}g/g$</TEX>), while, above <TEX>$175^{\circ}C$</TEX>, higher temperatures or prolonged processing times caused a decrease of acrylamide levels, finally disappeared at <TEX>$200^{\circ}C$</TEX> for 30 minute. Three major compounds were identified as 1,3-dihydroxypropanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyrane-4-one and 5-hydroxymethylfurfural, and three minor compounds also as 5-methylfurfural, 2-acetylpyrrole and N,N-dimethylcyclohexamine, from ethyl acetate or methanol extracts on FFAP or HP-5MS capillary column.

A fluorescence-based biosensor for the detection of organophosphate pesticides and chemical warfare agents

Recently elevated concerns of environmental contamination with organophosphate (OP) insecticides and the possible use of OP nerve agents by terrorists have spurred interest in developing more accurate and sensitive methods for field detection and discrimination of these neurotoxic agents. The analysis of OP neurotoxins typically requires sophisticated equipment, extensive sample preparation that is labor-intensive and prolonged processing time to validate the results. Therefore, a rapid, fiber-optic biosensor assay for the direct detection of organophosphates was developed in this study. The biorecognition element is an enzyme, organophosphate hydrolase (OPH), which was conjugated with both biotin, to anchor it and a fluorescence reporter carboxynaphthofluorescein (CNF). Avidin was attached to the polystyrene waveguide surface of a fluorescent detector, and the OPH–CNF–biotin biosensor conjugate was bound to the avidin. The recognition element (OPH) and reporter (CNF) molecules were designed to entertain OP samples with concentrations of neurotoxin as low as 0.05μM. Quantitative detection could be determined from 1 to 800μM for paraoxon and from 2 to 400μM for DFP. In addition, the system could also be used to provide continual remote monitoring and spectral fluorescent notification.

Brain stimulation and conscious experience: Electrical stimulation of the cortical surface at a threshold current evokes sustained neuronal activity only after a prolonged latency

Libet demonstrated that a substantial duration (>0.5–1.0 s) of direct electrical stimulation of the surface of a sensory cortex at a threshold or liminal current is required before a subject can experience a percept. Libet and his co-workers originally proposed that the result could be due either to spatial and temporal facilitation of the underlying neurons or additionally to a prolonged central processing time. However, over the next four decades, Libet chose to attribute the prolonged latency for evoking conscious experience to a prolonged central processing time. In my view, Libet has not provided any convincing evidence, either on the basis of his own past work or in his critique of my paper, for his hypothesis of a central processing time exceeding 0.5 s before conscious experience emerges following direct electrical threshold stimulation of the cortical surface. I stand by my original results and conclusion that such prolonged latencies are largely the consequence of a dynamically increasing cortical facilitatory process that begins hundreds of milliseconds before there is a sustained neuronal activation. In some cases, the facilitatory process must overcome an initial stimulus-induced inhibition before neuronal firing commences.

Influence of processing parameters on acrylamide formation during frying of potatoes.

Consistent evidence suggests that the probable human carcinogen acrylamide is formed in starch-rich foodstuffs through heat-induced interaction of asparagine and reducing sugars during Maillard browning. However, information regarding the influence of processing parameters on acrylamide formation is scarce. We investigated the impact of temperature, heating time, browning level, and surface-to-volume ratio (SVR) on acrylamide generation in fried potatoes. Acrylamide content was determined by liquid chromatography (LC) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). In potato shapes with low SVR, acrylamide content consistently increased with increasing temperature and processing times. By contrast, in shapes with intermediate to high SVR, maximal acrylamide formation occurred at 160-180 degrees C, while higher temperatures or prolonged processing times caused a decrease of acrylamide levels. Moreover, browning levels were not a reliable measure of acrylamide content in large-surface products.

Programming of expected and unexpected movements: effects on the onset of the lateralized readiness potential

When participants utilize prime information to prepare some or all aspects of the forthcoming movement, reaction time (RT) costs are obtained when the imperative response signal demands an unexpected rather than an expected movement. Longer RT in trials for which primes are invalid rather than valid, i.e., the response validity effect, are taken to reflect prolonged motoric processing time. The present study was designed to test this assumption by using the lateralized readiness potential (LRP) in order to reveal influences of response validity at motoric processes, pre-motoric processes, or both. In two response priming experiments LRP onset latency was examined when valid and invalid advance information about direction (Experiment 1) or about direction and hand (Experiment 2) was provided. RT revealed large response validity effects in both experiments. Analysis of LRP onsets provided strong evidence against the common assumption of a motoric locus of the RT increase in invalid trials. Rather, the present results suggest a pre-motoric locus of the response validity effect within information processing.

Event-related alpha synchronization/desynchronization in a memory-search task in adolescent survivors of childhood cancer

Objectives: Event-related desynchronization (ERD) and synchronization (ERS) of the 8–10 and 10–12 Hz frequency bands of the background EEG were studied in 19 adolescent survivors of childhood cancer (11 leukemias, 8 solid tumors) and in 10 healthy control subjects performing an auditory memory task. Methods: The stimuli were auditory Finnish words presented as a Sternberg-type memory-scanning paradigm. Each trial started with the presentation of a 4 word set for memorization whereafter a probe word was presented to be identified by the subject as belonging or not belonging to the memorized set. Results: Encoding of the memory set elicited ERS and retrieval ERD at both frequency bands. However, in the survivors of leukemia, ERS was turned to ERD during encoding at the lower alpha frequency band. ERD was lasting longer at the lower frequency band than at the higher frequency band, in each study group. At both frequency bands, the maximum of ERD was achieved later in the cancer survivors than in the control group. Conclusion: The previously reported type of ERD/ERS during an auditory memory task was reproducible also in the survivors of childhood cancer, at different alpha frequency bands. However, the temporal deviance in ERD/ERS magnitudes, in the cancer survivors, was interpreted to indicate that both survivor groups had prolonged information processing time and/or they used ineffective cognitive strategies. This finding was more pronounced in the group of leukemia survivors, at the lower alpha frequency band, suggesting that the main problem of this patient group might be in the field of attention.