On-line Formation Research Articles

The role of the hippocampus in memory and mental construction.

Much has been learned about the processes that support the remembrance of past autobiographical episodes and their importance for a number of cognitive tasks. This work has focused on hippocampal contributions to constructing coherent mental representations of scenarios for these tasks, which has opened up new questions about the underlying hippocampal mechanisms. We propose a new framework to answer these questions, which incorporates task demands that prompt hippocampal contributions to mental construction, the online formation of such mental representations, and how these demands relate to the functional organization of the hippocampus. Synthesizing findings from autobiographical memory research, our framework suggests that the interaction of two task characteristics influences the recruitment of the hippocampus: (1) the degree of task open-endedness (quantified by the presence/absence of a retrieval framework) and (2) the degree to which the integration of perceptual details is required. These characteristics inform the relative weighting of anterior and posterior hippocampal involvement, following an organizational model in which the anterior and posterior hippocampus support constructions on the basis of conceptual and perceptual representations, respectively. The anticipated outcome of our framework is a refined understanding of hippocampal contributions to memory and to the host of related cognitive functions.

Ultrasensitive and accelerated detection of ciguatoxin by capillary electrophoresis via on-line sandwich immunoassay with rotating magnetic field and nanoparticles signal enhancement

A sensitive and rapid on-line immunoassay for the determination of ciguatoxin CTX3C was developed based on a capillary mixing system, which was integrated with capillary electrophoresis (CE) separation and electrochemical (EC) detection. In the sandwich immunoassay system, anti-CTX3C-functionalized magnetic nanoparticles were used as immunosensing probes, and horseradish peroxidase (HRP) and anti-CTX3C antibody were bound onto the surface of gold nanoparticles (AuNPs) and used as recognition elements. Online formation of immunocomplex was realized in capillary inlet end with an external rotating magnetic field. Compared with classical HPLC-MS and ELISA, the assay adopting AuNPs as multienzyme carriers and online sandwich immunoassay format with rotating magnetic field exhibited higher sensitivity and shorter assay time. The linear range of the assay for CTX3C was from 0.6 to 150 ng/L with a correlation coefficient of 0.9948 (n = 2), and the detection limit (S/N = 3) was 0.09 ng/L. The developed assay showed satisfying reproducibility and stability, and it was successfully applied for the quantification of CTX3C in fish samples.

Online training on skin cancer diagnosis in rheumatologists: results from a nationwide randomized web-based survey.

Patients with inflammatory rheumatisms, such as rheumatoid arthritis, are more prone to develop skin cancers than the general population, with an additional increased incidence when receiving TNF blockers. There is therefore a need that physicians treating patients affected with inflammatory rheumatisms with TNF blockers recognize malignant skin lesions, requiring an urgent referral to the dermatologist and a potential withdrawal or modification of the immunomodulatory treatment. We aimed to demonstrate that an online training dedicated to skin tumors increase the abilities of rheumatologists to discriminate skin cancers from benign skin tumors. A nationwide randomized web-based survey involving 141 French rheumatologists was conducted. The baseline evaluation included short cases with skin lesion pictures and multiple choice questions assessing basic knowledge on skin cancers. For each case, rheumatologists had to indicate the nature of skin lesion (benign; premalignant/malignant), their level of confidence in this diagnosis (10-points Likert scale), and the precise dermatological diagnosis among 5 propositions. Different scores were established. After randomization, only one group had access to the online formation consisting in 4 e-learning modules on skin tumors, of 15 minutes each (online training group). After reevaluation, the trained and the non-trained group (control group) were compared. The primary end-point was the number of adequate diagnoses of the nature of the skin lesions. The mean number of adequate diagnosis for the benign versus premalignant/malignant nature of the lesions was higher in the online training group (13.4 vs. 11.2 points; p value <0.0001). While the other knowledge scores were also significantly higher, no statistical difference was observed on the level of self-confidence between the 2 groups. In conclusion, the online formation was effective to improve the rheumatologists’ ability to diagnose skin cancer.

Online news diffusion dynamics and public opinion formation: A case study of the controversy over judges’ personal opinion expression on SNS in Korea

On the Internet, the line between news and opinion becomes blurred in terms of content and form. In this sense, the processes of news diffusion on the Internet and online public opinion formation are integrated. This study selects one Korean example about the private tweet of a judge about government social network service (SNS) regulation and analyzes citation networks from one news/opinion to another news/opinion. By relying on social network analysis (SNA) methods, this study examines how news/opinions diffuse and how they interact and influence each other's ideological frame within agencies sharing the same ideology and between agencies whose ideologies contrast. The results show that public discourse on the Internet is clearly polarized and fragmented along political ideological lines. Additionally, the findings show that the winner is the conservative bloc because it succeeds in achieving within-bloc solidarity and ensures the resonance of news frames with the cultural values of Korean society. Implications for these findings in modern democracy are also discussed.

Adolescent online romantic relationship initiation: Differences by sexual and gender identification

Data from the national Teen Health and Technology Study of adolescents 13–18 years old (N = 5091) were used to examine online formation of romantic relationships. Results show that lesbian, gay, bisexual, transgender, and queer (LGBTQ) and non-LGBTQ adolescents similarly were most likely to have met their most recent boy/girlfriend in the past 12 months at school. However, they differed on many characteristics of romantic relationship initiation, including the extent to which they initiated romantic relationships online. LGBTQ and non-LGBTQ adolescents also differed on level of offline access to potential partners, offline popularity, and numerous other factors possibly related to online relationship initiation (e.g., Internet use and demographic factors). Even after adjusting for differences in these factors, LGBTQ adolescents were more likely than non-LGBTQ adolescents to find boy/girlfriends online in the past 12 months. The results support the rich-get-richer hypothesis as well as the social compensation hypothesis.

カメラ型オンライン地合計を活用した地合改善の取り組み

カメラ型オンライン地合計を活用した地合改善の取り組み

Activated carbon-modified knotted reactor coupled to electrothermal atomic absorption spectrometry for sensitive determination of arsenic species in medicinal herbs and tea infusions

A flow injection system based on a modified polytetrafluoroethylene (PTFE) knotted reactor (KR) was developed for arsenite [As(III)] and arsenate [As(V)] species preconcentration and determination by electrothermal atomic absorption spectrometry (ETAAS). Activated carbon (AC) was immobilized on the inner walls of a PTFE KR by a thermal treatment. A significant increase in analyte retention was obtained with the AC-modified KR (100%) as compared to the regular PTFE KR (25%). The preconcentration method involved the on-line formation of As(III)-ammonium pyrrolidinedithiocarbamate (As-APDC) complex, followed by its adsorption onto the inner walls of the AC-modified KR. After analyte retention, the complex was eluted with acetone directly into the graphite furnace of ETAAS. The parameters affecting the flow injection system were evaluated with a full central composite face centered design with three center points. Under optimum conditions, a preconcentration factor of 200 was obtained with 10ml of sample. The detection limit was 4ngL−1 and the relative standard deviation (RSD) for six replicate measurements at 0.2μgL−1 of As were 4.3% and 4.7% for As(III) and As(V), respectively. The developed methodology was highly selective towards As(III), while As(V), monomethylarsonic acid [MMA(V)] and dimethylarsinic [DMA(V)] were not retained in the AC-modified KR. The proposed method was successfully applied for As speciation analysis in infusions originated from medicinal herbs and tea.

Determination of Fluoride in Mouthwash Using Flow-injection Analysis with Spectrophotometric Detection

In this work, the development of flow system that is simple, precise and accurate for determining fluoride in mouthwash is described. The determination of fluoride was based on the on-line formation of a Fe(III)–salicylate complex, which is consumed in the presence of fluoride, generating the colourless hexafluoroferrate(III) complex ion, [FeF6]3-. The proposed procedure exhibits a linear concentration range of 8.0 × 10-5–1.2 × 10-3 mol L-1, a detection limit of 3.5 x 10-5 mol L-1, a higher sampling frequency of 44 h-1 and relative standard deviations below 0.2%. The interference of the red colour of the samples was removed using waste-seed specimens of Mabea fistulifera Mart. as a biosorbent material. Keywords: Biosorbent material, flow injection analysis, fluoride, hexafluoroferrate(III) complex, mouthwash, spectrophotometry.

Simultaneous quantification of catecholamines in rat brain by high-performance liquid chromatography with on-line gold nanoparticle-catalyzed luminol chemiluminescence detection.

A new method based on high-performance liquid chromatography (HPLC) coupled with on-line gold nanoparticle-catalyzed luminol chemiluminescence (CL) detection was developed for the simultaneous quantitation of catecholamines in rat brain. In the present CL system, gold nanoparticles were produced by the on-line reaction of H2 O2 , NaHCO3 -Na2 CO3 (buffer solution of luminol) and HAuCl4. Norepinephrine (NE), epinephrine (EP) and dopamine (DA) could strongly enhance the CL signal of the on-line gold nanoparticle-catalyzed luminol system. The UV-visible absorption spectra and transmission electron microscopy studies were carried out, and the CL enhancement mechanism was proposed. Catecholamines promoted the on-line formation of more gold nanoparticles, which better catalyzed the luminol-H2 O2 CL reaction. The good separation of NE, EP and DA was achieved with isocratic elution using a mixture of methanol and 0.2% aqueous phosphoric acid (5:95, v/v) within 8.5 min. Under the optimized conditions, the detection limits, defined as a signal-to-noise ratio of 3, were in the range of 1.32-1.90 ng/mL, corresponding to 26.4-38.0 pg for 20 μL sample injection. The recoveries of catecholamines added to rat brain sample were >94.6%, with the precisions <5.5%. The validated HPLC-CL method was successfully applied to determine NE and DA in rat brain without prior sample purification.

SAT0584 Impact of an Online Training on Skin Cancer Diagnosing in Rheumatologists, A Nationwide Randomized Web-Based Survey

BackgroundRecent data suggest an increased risk of melanoma and of cutaneous carcinoma in patients receiving TNF blockers. Thus, there is a need that rheumatologists improve their abilities to recognize skin...

カメラ型オンライン地合計を活用した地合改善の取り組み

カメラ型オンライン地合計を活用した地合改善の取り組み

Quadcopter formation flight control combining MPC and robust feedback linearization

This paper presents an integrated and practical control strategy to solve the leader–follower quadcopter formation flight control problem. To be specific, this control strategy is designed for the follower quadcopter to keep the specified formation shape and avoid the obstacles during flight. The proposed control scheme uses a hierarchical approach consisting of model predictive controller (MPC) in the upper layer with a robust feedback linearization controller in the bottom layer. The MPC controller generates the optimized collision-free state reference trajectory which satisfies all relevant constraints and robust to the input disturbances, while the robust feedback linearization controller tracks the optimal state reference and suppresses any tracking errors during the MPC update interval. In the top-layer MPC, two modifications, i.e. the control input hold and variable prediction horizon, are made and combined to allow for the practical online formation flight implementation. Furthermore, the existing MPC obstacle avoidance scheme has been extended to account for small non-apriorily known obstacles. The whole system is proved to be stable, computationally feasible and able to reach the desired formation configuration in finite time. Formation flight experiments are set up in Vicon motion-capture environment and the flight results demonstrate the effectiveness of the proposed formation flight architecture.

On the origin of islands

There is considerable controversy on island constraints on wh-dependencies in the psycholinguistic literature. One major point of contention is whether islands result from processing limitations such as working memory capacity or from domain-specific linguistic knowledge. The current study investigates whether islands can be reduced to processing considerations, by examining processing of another long-distance dependency, cataphora. If wh-dependencies with the licensing element (the verb or preposition) falling inside an island entail an unbearable memory load on the parser, then other dependencies, including cataphora, with a licensing element (the antecedent), falling inside an island, should yield a similar processing difficulty. The results from a self-paced reading experiment demonstrate that online formation of a cataphoric dependency is not affected by island constraints. We conclude that islands are not fully reducible to processing considerations and therefore must – at least in part – be of grammatical origin.

Automated magnetic sorbent extraction based on octadecylsilane functionalized maghemite magnetic particles in a sequential injection system coupled with electrothermal atomic absorption spectrometry for metal determination

A new automatic sequential injection (SI) system for on-line magnetic sorbent extraction coupled with electrothermal atomic absorption spectrometry (ETAAS) has been successfully developed for metal determination. In this work, we reported effective on-line immobilization of magnetic silica particles into a microcolumn by the external force of two strong neodymium iron boron (NdFeB) magnets across it, avoiding the use of frits. Octadecylsilane functionalized maghemite magnetic particles were used as sorbent material. The potentials of the system were demonstrated for trace cadmium determination in water samples. The method was based on the on-line complex formation with diethyldithiocarbamate (DDTC), retention of Cd–DDTC on the surface of the MPs and elution with isobutyl methyl ketone (IBMK). The formation mechanism of the magnetic solid phase packed column and all critical parameters (chemical, flow, graphite furnace) influencing the performance of the system were optimized and offered good analytical characteristics. For 5mL sample volume, a detection limit of 3ngL−1, a relative standard deviation of 3.9% at 50ngL−1 level (n=11) and a linear range of 9–350ngL−1 were obtained. The column remained stable for more than 600 cycles keeping the cost down in routine analysis. The proposed method was evaluated by analyzing certified reference materials and natural waters.

A novel on-line gold nanoparticle-catalyzed luminol chemiluminescence detector for high-performance liquid chromatography

A novel on-line gold nanoparticle-catalyzed luminol–H2O2 chemiluminescence (CL) detector for high-performance liquid chromatography (HPLC) was established, in which gold nanoparticles were produced by the on-line reaction of H2O2, NaHCO3–Na2CO3 (buffer solution of luminol), and HAuCl4. Eight phenolic compounds (gallic acid, protocatechuic acid, protocatechuic aldehyde, 2,5-dihydroxybenzoic acid, caffeic acid, 2,3-dihydroxybenzoic acid, (+)-catechin, and (−)-epicatechin) were chosen as the model compounds. Every separated phenolic compound in the column eluent strongly enhanced the CL signal of on-line gold nanoparticle-catalyzed luminol system. The CL and UV–visible absorption spectra and transmission electron microscopy studies were carried out, and the CL enhancement mechanism was ascribed to that the presence of phenolic compound promoted the on-line formation of 38-nm-diameter gold nanoparticles, which better catalyzed the luminol–H2O2 CL reaction. The effects of methanol and phosphoric acid in the proposed HPLC configuration were performed by two gradient elution programs, and the baseline profile revealed that on-line gold nanoparticle-catalyzed luminol–H2O2 CL detector had better compatibility than 38nm gold colloids–luminol–H2O2 CL detector. The proposed CL detector exhibits excellent analytical performance with the low detection limit (S/N=3) of 0.53–0.97ng/mL (10.6–19.4pg) phenolic compounds, and offers a new strategy for developing on-line nanoparticle-catalyzed CL detector for HPLC with sensitive analysis.

Pressurised hot water extraction with on-line particle formation by supercritical fluid technology

In this work, an on-line process for pressurised hot water extraction (PHWE) of antioxidants from plants as well as drying of the extract in one step by particle formation based on the use of supercritical carbon dioxide (SC-CO(2)) has been developed. This process has been called WEPO®, water extraction and particle formation on-line. With this process, dried extracts from onion with the same composition of quercetin derivatives as non-dried extracts have been obtained as a fine powder with spherical particles from 250 nm to 4 μm in diameter. The major compounds present in the extract were quercetin-3,4'-diglucoside, quercetin-4'-glucoside and quercetin. An auxiliary inert gas (hot N(2)) was used to enhance the drying process. Parameters such as temperature (120 °C), SC-CO(2) and N(2) pressures (80 and 12.5 bar, respectively) and flow rate of SC-CO(2) (10 ml/min), have been settled by trial-and-error in order to achieve a fine and constant spray formation. Water content, size and morphology, antioxidant capacity and quercetin content of the particles were studied to evaluate the efficiency of the WEPO process. Results were compared with the ones from extracts obtained by continuous flow PHWE followed by freeze-drying. Results showed that both processes gave similar results in terms of antioxidant capacity, concentration of quercetin derivatives and water content, while only WEPO was able to produce defined spherical particles smaller than 4 μm.

A Sandwich Electrochemical Immunosensor Using Magnetic DNA Nanoprobes for Carcinoembryonic Antigen

A novel magnetic nanoparticle-based electrochemical immunoassay of carcinoembryonic antigen (CEA) was designed as a model using CEA antibody-functionalized magnetic beads [DNA/Fe3O4/ZrO2; Fe3O4 (core)/ZrO2 (shell) nano particles (ZMPs)] as immunosensing probes. To design the immunoassay, the CEA antibody and O-phenylenediamine (OPD) were initially immobilized on a chitosan/nano gold composite membrane on a glassy carbon electrode (GCE/CS-nano Au), which was used for CEA recognition. Then, horseradish peroxidase (HRP)-labeled anti-CEA antibodies (HRP-CEA Ab2) were bound to the surface of the synthesized magnetic ZMP nanoparticles as signal tag. Thus, the sandwich-type immune complex could be formed between secondary antibody (Ab2) modified DNA/ZMPs nanochains tagged by HRP and GCE/CS-nano Au. Unlike conventional nanoparticle-based electrochemical immunoassays, the recognition elements of this immunoassay included both electron mediators and enzyme labels, which obviously simplifies the electrochemical measurement process. The sandwich-type immunoassay format was used for online formation of the immunocomplex of CEA captured in the detection cell with an external magnet. The electrochemical signals derived from HRP during the reduction of H2O2 with OPD as electron mediator were measured. The method displayed a high sensitivity for CEA detection in the range of 0.008–200 ng/mL, with a detection limit of 5 pg/mL (estimated at a signal-to-noise ratio of 3). The precision, reproducibility, and stability of the immunoassay were good. The use of the assay was evaluated with clinical serum samples, and the results were in excellent accordance with those obtained using the standard enzyme-linked immunosorbent assay (ELISA) method. Thus, the magnetic nanoparticle-based assay format is a promising approach for clinical applications, and it could be further developed for the detection of other biomarkers in cancer diagnosis.

Wired Youth: The Social World of Adolescence in the Information Age

1. The Information Age, Youth and Social Networks. 2. The Internet at Home. 3. Sociability and Internet Use. 4. Online Relationship Formation. 5. ICT and Existing Ties. 6. The Impact of ICT on Social Network Structure 7. Online Communication and Negative Social Ties 8. Summary and Discussion.

Flow injection online solid phase extraction system using Oasis-HLB™ micro-cartridge for chromium(vi) and copper determination by flame atomic absorption spectrometry

An online flow injection sorption preconcentration method for automatic trace chromium(VI) and copper determination in environmental water samples was developed, using flame atomic absorption spectrometry (FAAS). The use of hydrophobic reversed-phase co-polymeric sorbent material Oasis-HLB in readily exchangeable micro-cartridge format was estimated. Effective online formation and retention of sodium diethyldithiocarbamate (DDTC) chelate complexes of analytes were achieved at pH 2.0, while highest elution effectiveness was observed with methanol. The sorbent and the micro-cartridge exhibited high long term chemical and mechanical stability with fast kinetics for both metals. Several analytical parameters like sample acidity, DDTC concentration, loading/elution flow rate and preconcentration time governing the efficiency of the method were evaluated. For 90 s preconcentration time (10.0 mL of sample volume) and sampling frequency 24 h−1, the enhancement factor was 70 and 195, the detection limit (3s) found to be 0.8 μg L−1 and 0.1 μg L−1 with relative standard deviations 3.5% (at 10.0 μg L−1) and 2.7% (at 5.0 μg L−1) for chromium(VI) and copper respectively. The presented method was evaluated by analyzing certified reference materials and spiked natural water samples.

Simultaneous speciation of inorganic arsenic and antimony in water samples by hydride generation-double channel atomic fluorescence spectrometry with on-line solid-phase extraction using single-walled carbon nanotubes micro-column

A new method was developed for the simultaneous speciation of inorganic arsenic and antimony in water by on-line solid-phase extraction coupled with hydride generation-double channel atomic fluorescence spectrometry (HG-DC-AFS). The speciation scheme involved the on-line formation and retention of the ammonium pyrrolidine dithiocarbamate complexes of As(III) and Sb(III) on a single-walled carbon nanotubes packed micro-column, followed by on-line elution and simultaneous detection of As(III) and Sb(III) by HG-DC-AFS; the total As and total Sb were determined by the same protocol after As(V) and Sb(V) were reduced by thiourea, with As(V) and Sb(V) concentrations obtained by subtraction. Various experimental parameters affecting the on-line solid-phase extraction and determination of the analytes species have been investigated in detail. With 180 s preconcentration time, the enrichment factors were found to be 25.4 for As(III) and 24.6 for Sb(III), with the limits of detection (LODs) of 3.8 ng L − 1 for As(III) and 2.1 ng L − 1 for Sb(III). The precisions (RSD) for five replicate measurements of 0.5 μg L −1 of As(III) and 0.2 μg L −1 of Sb(III) were 4.2 and 4.8%, respectively. The developed method was validated by the analysis of standard reference materials (NIST SRM 1640a), and was applied to the speciation of inorganic As and Sb in natural water samples.