New approach for mapping and physiological test of silica nanoparticles accumulated in sweet basil (Ocimum basilicum) by LA-ICP-MS.

Behavior of silica nanoparticles (SiNPs) in sweet basil was studied using laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) as an in situ monitoring tool. Although the use of SiNP for environmental applications is interesting, detailed studies in plants for distributional mapping and quantitative determination have been difficult because the detection of 28Si+ suffers from severe molecular interference and high background in ICP-MS. In this work, yttrium/fluorescein-isothiocyanate-doped silica nanoparticles (Y/FITC-doped SiNPs) synthesized in our lab were used to substitute for undoped SiNP, allowing the doped 89Y+ to be monitored instead of 28Si+, while retaining the same surface properties. Based on this model, the physiological influence was studied by nourishing them with a nutrient solution spiked with the synthesized SiNPs and a co-pollutant, Cs ion. Mapping images obtained by LA-ICP-MS showed distinct accumulation patterns associated with exposure. For example, Cs was distributed widely over the leaves, whereas SiNPs were concentrated in specific regions such as main veins, leaf margins, and tips. Furthermore, the possible effect of SiNP and Cs on the photochemical reaction was confirmed through monitoring the change of the concentration of chlorophyll and carotenoid and the superoxide dismutase (SOD) activity.

Magnetophoretic separation ICP-MS immunoassay using Cs-doped multicore magnetic nanoparticles for the determination of salmonella typhimurium.

In this work, a magnetophoretic separation ICP-MS immunoassay using newly synthesized multicore magnetic nanoparticles (MMNPs) was developed for the determination of salmonella typhimurium (typhi). The uniqueness of this method was the use of MMNPs doped with Cs for both separation and detection, which enable us to achieve fast analysis, high sensitivity, and good reliability. For demonstration, heat-killed typhi in a phosphate buffer solution was determined by ICP-MS after the MMNP-typhi reaction product was separated from unreacted MMNPs in a micropipette tip filled with 25% polyethylene glycol through magnetophoretic separation. The calibration curve obtained by plotting 133Cs intensity vs. the number of synthetic standard, showed a coefficient of determination (R2) of 0.94 with a limit of detection (LOD) of 102 cells/mL without cell culturing. Excellent recoveries, between 98-100%, were obtained from four replicates and compared with a sandwich-type ICP-MS immunoassay for further confirmation.

Metal-doped inorganic nanoparticles for multiplex detection of biomarkers by a sandwich-type ICP-MS immunoassay.

Metal-doped inorganic nanoparticles were synthesized for the multiplex detection of biomarkers by a sandwich-type inductively coupled plasma mass spectrometry (ICP-MS) immunoassay. The synthesized Cs-doped multicore magnetic nanoparticles (MMNPs) were used not only for magnetic extraction of targets but also for ratiometric measurement in ICP-MS. In addition, three different metal/dye-doped silica nanoparticles (SNPs) were synthesized as probes for multiplex detection: Y/RhBITC (rhodamine B isothiocyanate)-doped SNPs for CRP (cardiovascular disease), Cd/RhBITC-doped SNPs for AFP (tumor), and Au/5(6)-XRITC (X-rhodamine-5-(and-6)-isothiocyanate)-doped SNPs for NSE (heart disease). For quantification, the doped metals of SNPs were measured by ICP-MS and then the signal ratio to Cs of MMNPs was plotted with respect to the concentration of targets by a ratiometry. Limits of detection (LOD) of 0.35 ng/mL to 77 ng mL(-1) and recoveries of 83%-125% were obtained for serum samples spiked with the biomarkers. Since no sample treatment was necessary prior to the extraction, the proposed method provided short analysis time and convenience for the multiplex determination of biomarkers, which will be valuable for clinical application.

Chemiluminescence immunoassay using magnetic nanoparticles with targeted inhibition for the determination of ochratoxin A.

In this work, a chemiluminescence (CL) immunoassay with targeted inhibition was developed for the determination of toxins in food products. For sample treatment, amine-functionalized magnetic nanoparticles (MNPs) were synthesized to extract target molecules, and horseradish peroxidase (HRP) tagged on an antibody was used as a label for CL reaction. In particular, amine-targeted inhibition using aldehyde, i.e., specifically capping the amine with an alkyl group, was developed for a non-specific extraction platform to lower background and improve signal-to-background ratio. For demonstration, ochratoxin A (OTA) was determined in rice using a lab-built drop-type chemiluminescence (DCL) system with luminol-H2O2 reagent. The obtained limit of detection was 1.39 pg mL(-1), which was about 7.3 times better than that of ELISA. Recovery of the method in the range of 87-99% was observed, which was compared with ELISA.

Laser-induced fluorescence reader with a turbidimetric system for sandwich-type immunoassay using nanoparticles.

A unique laser-induced fluorescence (LIF) reader equipped with a turbidimetric system was developed for a sandwich-type immunoassay using nanoparticles. The system was specifically designed to reduce experimental error caused by particle loss, aggregation and sinking, and to improve analytical performance through ratiometric measurement of the fluorescence with respect to the turbidimetric absorbance. For application to determine the concentration of salinomycin, magnetic nanoparticles (MNPs) and FITC-doped silica nanoparticles (colored balls) immobilized with antibody were synthesized for magnetic extraction and for tagging as a fluorescence probe, respectively. The detection limit of about 39 pg mL(-1) was obtained, which was an improvement of about 2-fold compared to that obtained without employment of the turbidimetric system. Calibration linearity and sensitivity were also improved, with increase from 0.8601 to 0.9905 in the R(2)-coefficient and by 1.92-fold for the curve slope, respectively. The developed LIF reader has the potential to be used for fluorescence measurements using various nanomaterials, such as quantum dots.

Cerium oxide-deposited mesoporous silica nanoparticles for the determination of carcinoembryonic antigen in serum using inductively coupled plasma-mass spectrometry.

CeO2-deposited mesoporous silica nanoparticles were synthesized as a probe to determine carcinoembryonic antigen (CEA) in serum by inductively coupled plasma-mass spectrometry (ICP-MS). The prepared mesoporous nanoparticles were modified and tagged to the target for sandwich-type immunoassay. Fe3O4 magnetic nanoparticles (MNPs) were also synthesized and immobilized with antibody to extract the target biomarker. The calibration curve of the synthesized CeO2-deposited silica nanoparticles, which was plotted by the signal ratio of (140)Ce/(57)Fe measured by ICP-MS vs. the concentration of CEA, showed excellent linearity and sensitivity owing to the signal amplification and low spectral interference. Under optimal conditions, the sandwich-type analytical method was applied to determine CEA in serum spiked in the range of 0.001-5 ng mL(-1) and showed a limit of detection of 0.36 ng mL(-1). Since the deposited CeO2 in the mesoporous silica layer can be substituted by other metal compounds, various kinds of metal-deposited nanoparticles can be prepared as probe materials for multiplex detection in bioanalysis.

Ministry of Health Clinical Practice Guidelines: Diabetes Mellitus.

The Ministry of Health (MOH) have updated the clinical practice guidelines on Diabetes Mellitus to provide doctors and patients in Singapore with evidence-based treatment for diabetes mellitus. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Diabetes Mellitus, for the information of SMJ readers. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/content/moh_web/healthprofessionalsportal/doctors/guidelines/cpg_medical.html. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Sample treatment platform using nanoparticles to determine salinomycin in flesh and meat.

In this work, we developed a sensitive and selective analytical method of determining salinomycin in flesh and meat using a lab-built laser induced fluorescence microscope (LIFM) with nanoparticles. Two types of nanoparticles, Cy5 doped core-shell silica nanoparticles as a probe and magnetic nanoparticles (MNPs) to extract the target antibiotic from the treated sample, were synthesized and modified for chemical and enzymatic binding. After optimization, the newly developed method was applied to ham, chicken, and meat samples for the quantitative determination of salinomycin. The limits of detection (LODs) obtained from the calibration curve were 48-590 pg/mL, which was about 100-fold lower than that of the ELISA method.

An individual-specific gait pattern prediction model based on generalized regression neural networks.

Robotics is gaining its popularity in gait rehabilitation. Gait pattern planning is important to ensure that the gait patterns induced by robotic systems are tailored to each individual and varying walking speed. Most research groups planned gait patterns for their robotics systems based on Clinical Gait Analysis (CGA) data. The major problem with the method using the CGA data is that it cannot accommodate inter-subject differences. In addition, CGA data is limited to only one walking speed as per the published data. The objective of this work was to develop an individual-specific gait pattern prediction model for gait pattern planning in the robotic gait rehabilitation systems. The waveforms of lower limb joint angles in the sagittal plane during walking were obtained with a motion capture system. Each waveform was represented and reconstructed by a Fourier coefficient vector which consisted of eleven elements. Generalized regression neural networks (GRNNs) were designed to predict Fourier coefficient vectors from given gait parameters and lower limb anthropometric data. The generated waveforms from the predicted Fourier coefficient vectors were compared to the actual waveforms and CGA waveforms by using the assessment parameters of correlation coefficients, mean absolute deviation (MAD) and threshold absolute deviation (TAD). The results showed that lower limb joint angle waveforms generated by the gait pattern prediction model were closer to the actual waveforms compared to the CGA waveforms.

Application of magnetic and core-shell nanoparticles to determine enrofloxacin and its metabolite using laser induced fluorescence microscope.

A unique analytical method using nanoparticles and laser-induced fluorescence microscopy (LIFM) was developed to determine enrofloxacin in this work. For sample pretreatment, two different kinds of particles, i.e., synthesized dye-doped core-shell silica nanoparticles and magnetic micro-particles (MPs), were used for fluorescent tagging and concentrating the enrofloxacin, respectively. The antibody of enrofloxacin was immobilized on the synthesized FITC-doped core-shell nanoparticles, and the enrofloxacin target was extracted by the MPs. At this moment, the average number of antibodies on each core-shell silica nanoparticle was ~0.9, which was determined by the fluorescence ratiometric method. The described method was demonstrated for a meat sample to determine enrofloxacin using LIFM, and the result was compared with enzyme-linked immunosorbent assay (ELISA). The developed technique allowed the simplified analytical procedure, improved the detection limit about 54-fold compared to ELISA.

Direct and simultaneous determination of Co and Cu on a silicon wafer using a chemiluminescence system.

In this work, we developed a drop-type chemiluminescence (CL) system with a partial least squares (PLS) calibration in which the coaxial optical fiber sensing head was developed for sampling and detection to determine Cu(2+) and Co(2+) on a silicon wafer directly. The use of time-resolved signal generation and PLS calibration in addition to CL allowed us to determine the metal ions simultaneously and selectively, based on the kinetic difference of Cu and Co ions in the luminol-H(2)O(2) system. Two component mixtures with a set of 15 wafer fragments were orthogonally calibrated. After prediction test, the method was applied to an intentionally contaminated silicon wafer and validated by inductively coupled plasma-mass spectrometer (ICP-MS) measurement with a HF-HNO(3) scanning solution. The average concentrations of Cu(2+) and Co(2+) of 3.45 (±0.95) × 10(13) and 2.30 (±1.18) × 10(11) atoms per cm(2), respectively, were obtained, which were very close to the ICP-MS results of 3.70 × 10(13) for Cu(2+) and 2.46 × 10(11) atoms per cm(2) for Co(2+). In conclusion, this drop mode CL showed almost more than 10 times better reproducibility than the typical batch mode for the profile measurement. Moreover, the adoption of PLS calibration added the function of selectivity for the simultaneous determination to this CL system, in addition to the direct mapping capability for the solid surface analysis.

Core-shell silica nanoparticles synthesized for quantitative study of DNA cleavage by laser-induced fluorescence microscopy.

Dye-doped silica nanoparticles (C dots) were synthesized in reverse microemulsions and used to quantitatively examine DNA cleavage in the presence of transition metal ions. The cores were synthesized as fluorescein isothiocyanate (FITC)-doped silica nanoparticles and the shells' surfaces were modified with single-stranded DNA oligomers tagged with Cy5 fluorophores. DNA cleavage induced by heavy metal ions was estimated by comparing the fluorescence of Cy5 before and after reaction with metal ions. For this, a lab-built laser-induced fluorescence microscope equipped with a charge coupled device (CCD) camera, for imaging, and photomultiplier tube, for photon counting, was used. FITC fluorescence from the core was measured as an internal standard to compensate for possible loss of the beads during the treatment. The cleavage of DNA in air in the presence of Pb(2+), Cd(2+), and Hg(2+) at 1 ng/mL was found to be 14%, 6%, and 20%, respectively, and was significantly reduced to below 9% under N(2) gas, indicating that the main cleavage source was oxygen in air. The most significant DNA cleavage was observed with the addition of hydrogen peroxide. This analytical method using dye-doped C dots provided convenient handling and quantification of the estimation of metal-DNA interaction with a detection limit of 34.9 pmol/mL.

Subject-specific lower limb waveforms planning via artificial neural network.

Robotic is gaining its popularity in gait rehabilitation. Gait pattern planning is important, in order to ensure the gait patterns induced by robotic systems on the patient are natural and smooth. It is known that the gait parameters (stride length, cadence) are the key factors, which affect gait pattern. However, a systematic methodology for gait pattern planning is missing. Therefore, a gait pattern generation methodology, GaitGen, was proposed in our previous work. In this paper, we introduce a new model to enhance the proposed methodology for generating the joint angle waveforms of the lower limb during walking, with the gait parameters and the lower limb anthropometric data as input. The walking motion was captured with a motion capture system using passive markers. The waveforms of lower limb joint angles were calculated from the experimental data and the waveforms were then decomposed into Fourier coefficients. Therefore, each joint angle waveform can be represented by a Fourier coefficient vector containing eleven elements to facilitate the waveform analysis. Multi-layer perceptron neural networks (MLPNNs) were designed to predict the Fourier coefficient vectors for specific subject and desired gait parameters. Assessment parameters such as correlation coefficient, mean absolute deviation (MAD) and threshold absolute deviation (TAD) were calculated to examine the quality of MLPNNs' prediction. The constructed waveforms from predicted Fourier coefficient vectors were compared with the actual waveforms calculated from experimental data by using the above-mentioned assessment parameters. The results show that the constructed waveforms closely match the experimental waveforms based on the assessment parameter outcomes.

Chemiluminescence system for direct determination and mapping of ultra-trace metal impurities on a silicon wafer.

A highly sensitive chemiluminescence (CL) system which consumed low sample and reagent volumes in the microlitre range was developed for direct determination and mapping of ultra-trace metal contaminants on solid surfaces, such as silicon wafers or flat display panels. The analytical result of the system was confirmed with ICP-MS. The system was composed of a scanner, sensor and a wafer moving stage. The scanner, with a scanning tip made of 0.03'' i.d. PTFE tubing, was used to collect metal impurities on the wafer surface with 5 µL of scanning solution. A coaxial sensing head of about 13 mm o.d. and 110 mm height was designed both to inject a luminescent reagent of luminol-H(2)O(2) mixture and to collect the luminescence light resulting from the reaction with metal ions of Co(2+), Fe(2+), Cu(2+), and Ni(2+). Due to the almost zero background, an extremely low limit of detection of 20.8 pg/mL for Co(2+) in 1% hydrofluoric acid (HF) was obtained from the calibration curve. In order to map the spatial distribution of the impurities, 11 cross sections of a Co-contaminated wafer were selected and scanned individually with a diluted HF solution. A contaminant level of 1.45-7.11 × 10(11) atoms cm(-2) was obtained for each section with an average of 4.21 × 10(11) atoms cm(-2), which was similar to the analytical result of 5.48 × 10(11) atoms cm(-2) obtained from vapor phase deposition-inductively coupled plasma-mass spectrometry (VPD-ICP-MS). Although this CL system does not have selectivity for each specific metal ion, its high sensitivity facilitates the monitoring and mapping of metal impurities of Co, Fe, Cu, etc. on the wafer directly and it can be used as an on-line inspection sensor for the first time in the semiconductor industry.

Health Promotion Board-Ministry of Health clinical practice guidelines: functional screening for older adults in the community.

The Health Promotion Board (HPB) and the Ministry of Health (MOH) publish clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the HPB-MOH clinical practice guidelines on Functional Screening for Older Adults in the Community, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Health Promotion Board website (http://www.hpb.gov.sg/uploadedFiles/HPB_Online/Publications/CPGFunctionalscreening.pdf). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Effects of differentiated music on cycling time trial.

The aim of this study was to investigate the effects of music introduced and removed during a 10-km cycling time trial with reference to Rejeski's parallel processing theory and Karageorghis, Terry and Lane's conceptual framework for the prediction of responses to asynchronous music during sub-maximal exercise. A range of performance variables, ratings of perceived exertion, positive affect, negative affect, and blood lactate were assessed. Eleven males (mean age=24.9, s=6.1 years) completed a 10-km time trial under three conditions; no music, music played initially then removed between 5-10 km, and music played between 5-10 km only. Variables of time, power, cadence, speed, RPE, blood lactate, positive and negative affect were analysed using a ConditionxDistance ANOVA. There was no significant main effect for music conditions for the performance variables, perceived exertion, blood lactate, and affect (p>0.05). Nevertheless, a significant interaction effect for ConditionxDistance was found for cycling speed, with participants cycling 1-1.25 km/h faster at the start of the music introduced time trial than in both the music removed and no music time trials (p<0.05). The results indicate that performance and affect during a 10 km time trial are influenced by the introduction and/or removal of music during exercise and this finding can be used to extend current theory as it does not specifically address the periodic use music. The fact that participants exercised harder when they expected music to be introduced at a later stage illustrates the behavioural influences that music can engender during self-paced exercise.

Systemic complications after head injury: a clinical review.

Non-neurological organ dysfunction is common after traumatic brain injury and is an independent contributor to morbidity and mortality. It represents a risk factor that is potentially amenable to treatment, and early recognition and prompt intervention may improve outcome. This article reviews the current evidence for the mechanisms and treatment of non-neurological organ dysfunction after head injury.

Dropping mode chemiluminescence system with a poly(dimethylsiloxane) cell for applications to semiconductor processes.

A lab-made chemiluminescence system with a polymer cell for the dropping mode was used to determine ultra-trace metal ions in hydrofluoric acid (HF) and the standard cleaning solution-1 (SC-1) used in semiconductor manufacturing processes. The cell was made of poly(dimethylsiloxane) (PDMS) with dimensions of about 10 mm i.d. and 8 mm in height, was cheap, disposable, chemically inert to alkalis and acids, especially HF, and was optically transparent in the visible region. A dropping method for sample injection was adopted to minimize pulsation and the dramatic pH change of the luminol-H2O2 reagent when adding the sample. The average sample weight of a single drop was 7.17 microg with a remarkable reproducibility of +/-0.37% relative standard deviation (RSD). This very small sample volume compared to the reagent volume made it possible to avoid any precipitation being formed when HF was added. For an application, Fe was determined in deionized (d.i.) water, sulfuric acid, SC-1, and a diluted HF (1:200 DHF) solution, which have been commonly used in semiconductor manufacturing processes. The limits of detections for Fe2+ in those solutions were found to be in the range of 42 to 62 pg ml(-1). Based on the analytical results, this chemiluminescence system with the PDMS cell was reproducible, resistant to HF, had less sample consumption and waste generation, and was sensitive enough to apply to the semiconductor industry as an on-line monitoring sensor. Although this chemiluminescence system does not have selectivity for each specific metal ion, it can be used as an on-line sensor to monitor the metal contamination level of Fe, Cu, Co, etc., which are major elements of concern in the semiconductor manufacturing process.

Low-pressure ICP-AES with electrothermal vaporizer and a pneumatic nebulizer for aqueous sample introduction.

A typical electrothermal vaporization (ETV) using a tantalum was built for low-pressure ICP-AES. The analytical performance of the ETV was tested and compared with that of a PFA pneumatic nebulizer with a double membrane desolvator (DMD). The limits of detection of the ETV were obtained in the range of 3.4 ng to 758 ng for Zn, Cu, Co, Fe, and Mg, while those of the PFA nebulizer were in the range of 53 ppb to 286 ppb. A relative standard deviation (RSD) of 4.3 - 8.5% for ETV was obtained, while 2.15 - 6.84% RSD was found for DMD.

Development of an automated protein-tyrosine phosphatase 1B inhibition assay and the screening of putative insulin-enhancing vanadium(IV) and zinc(II) complexes.

The inhibition of protein-tyrosine phosphatase 1B (PTP1B) is a potential target for treatment of type 2 diabetes. Vanadium and zinc metal coordinated complexes have insulin-enhancing activities, and while vanadium compounds inhibit PTP1B, little is known on the mode of action of zinc compounds. In this study we developed an automated PTP1B inhibition assay that allows for a rapid assessment of the PTP1B inhibition strength of candidate compounds. Synthetic vanadium(IV) and zinc(II) complexes were evaluated: IC50 values for vanadium complexes ranged from 0.06 to 0.8 microM whereas for zinc compounds, values were above 10 microM. Vanadium sulfate, a non-conjugated inorganic salt, had stronger inhibition activity than any of the conjugated metal complexes.