Fast Peak Research Articles

Design and in silico evaluation of an intraperitoneal–subcutaneous (IP–SC) artificial pancreas

Prandial glucose regulation is a major challenge for the artificial pancreas using subcutaneous insulin (without a feedforward bolus) due to insulin's slow absorption-peak (50–60min). Intraperitoneal insulin, with a fast absorption peak (20–25min), has been suggested as an alternative to address these limitations. An artificial pancreas using intraperitoneal insulin was designed and evaluated on 100 in silico subjects and compared with two designs using subcutaneous insulin with and without a feedforward bolus, following the three meal (40–70g-carbohydrates) evaluation protocol. The design using intraperitoneal insulin resulted in a significantly lower postprandial blood glucose peak (38mg/dL) and longer time in the clinically accepted region (13%) compared to the design using subcutaneous insulin without a feedforward bolus and comparable results to a subcutaneous feedforward bolus design. This superior regulation with minimal user interaction may improve the quality of life for people with type 1 diabetes mellitus.

High-Intensity Interval Training for Improvement of Overhand Throwing Velocity

Context:High intensity interval training (HIIT) has been shown to improve muscle power and endurance, as well as aerobic power.Objective:To assess the effects of HIIT that utilizes resistive elastic bands to improve overhand throwing velocity.Participants:Healthy female volunteers (n = 13) ranging in age from 18–29 years.Interventions:Participants were randomly assigned to either a control group or an experimental group that exercised 3 days per week for 3 weeks. Each training session involved performance of 5 sets of 20 throwing motions against elastic band resistance, which was performed by both extremities.Main Outcome Measures:Maximal oxygen consumption was measured during performance of a graded exercise test that utilized an upper extremity cycle ergometer. A radar gun was used to assess peak throwing velocity and the extent to which throwing velocity was sustained during performance of a 20-throw endurance test.Results:After completing the training, the experimental group exhibited faster peak throwing velocity (61.6 ± 6.6 km/hr to 63.2 ± 8.6 km/hr) and a reduced fatigue index (1.18 ± 0.16 to 1.01 ± 0.02). Training also resulted in a 14% improvement in maximum oxygen consumption (1.40 ± 0.46 L/min to 1.60 ± 0.49 L/ min) and longer time to fatigue (9.99 ± 1.84 min to 11.43 ± 2.29 min).Conclusion:The high-intensity interval training program was effective for improvement of overhand throwing performance.

Newborn screening for haemoglobinopathies by high performance liquid chromatography (HPLC): diagnostic utility of different approaches in resource-poor settings.

Sickle cell disease is a major health burden in India. The aim of the study was to compare the diagnostic utility of two different approaches on automated high performance liquid chromatography (HPLC) for newborn screening for sickle cell disorders and other haemoglobinopathies in India. Newborn babies of sickle heterozygous mothers were tested by HPLC using two different kits, the β-thal short kit, which is routinely used for screening for haemoglobinopathies in most laboratories, and the sickle cell short kit which is specific only for neonatal samples. Confirmation of the sickle and α genotypes was done by molecular analysis. Of the 601 babies tested, 276 were normal, 284 were sickle heterozygous and 41 were sickle homozygous using the β-thal short kit. Using the sickle cell short kit, a discrepancy was seen in one newborn sample where a normal baby was identified as a sickle heterozygous baby. α-Genotyping was done in 42 babies and 16 of them had α gene deletions. The presence of α thalassaemia could be suspected in 15 of these 16 babies based on a spike at the start of the chromatogram using the β-thal short kit. In comparison, using the sickle cell short kit the diagnosis of α thalassaemia was difficult based on the percentage of the FAST peak. Further, other rare α chain Hb variants were also missed. The β-thal short kit was more versatile than the sickle cell short kit for screening for haemoglobinopathies in newborns in our population.

Knee angular displacement analysis in amateur ballet dancers: A pilot study

Ballet gestures are highly non-anatomical and physiological, leading to compensatory behaviors. The knee joint is most affected by this behavior, leading to an increase risk of injury. Our purpose is to describe the knee angular displacement in amateur dancers, during a demi-plié exercise, with emphasis on valgus mechanisms frequency. Methods: 192 demi-pliés collected in six amateur female dancers (mean age = 15.33 ± 1.37 years), were analyzed regarding sagittal and frontal plane angular displacement, with an electrogoniometer connected to a signal acquisition unit at 1000 Hz. Results: all subjects presented valgus peaks along the trials, despite the global varus tendency of the knee frontal plane behavior. A significant positive correlation between the frequency of valgus and practice time was noted. Discussion: A variable angular frontal displacement was observed, with some trials comprehending a high incidence of valgus peaks along the ascending or descending phase of the demi-plié exercise. Conclusion: the frontal knee angle behavior is variable. It may present fast peaks of valgus or an initial trend of varus/valgus that is different from the global varus trend. The analysis of the activity should be considered in the training. The practice time may be related to the observed behavior.

Oligomycin A-induced inhibition of mitochondrial ATP-synthase activity suppresses boar sperm motility and in vitro capacitation achievement without modifying overall sperm energy levels.

Incubation of boar spermatozoa in a capacitation medium with oligomycin A, a specific inhibitor of the F0 component of the mitochondrial ATP synthase, induced an immediate and almost complete immobilisation of cells. Oligomycin A also inhibited the ability of spermatozoa to achieve feasible in vitro capacitation (IVC), as measured through IVC-compatible changes in motility patterns, tyrosine phosphorylation levels of the acrosomal p32 protein, membrane fluidity and the ability of spermatozoa to achieve subsequent, progesterone-induced in vitro acrosome exocytosis (IVAE). Both inhibitory effects were caused without changes in the rhythm of O2 consumption, intracellular ATP levels or mitochondrial membrane potential (MMP). IVAE was accompanied by a fast and intense peak in O2 consumption and ATP levels in control spermatozoa. Oligomycin A also inhibited progesterone-induced IVAE as well as the concomitant peaks of O2 consumption and ATP levels. The effect of oligomycin on IVAE was also accompanied by concomitant alterations in the IVAE-induced changes on intracellular Ca(2+) levels and MMP. Our results suggest that the oligomycin A-sensitive mitochondrial ATP-synthase activity is instrumental in the achievement of an adequate boar sperm motion pattern, IVC and IVAE. However, this effect seems not to be linked to changes in the overall maintenance of adequate energy levels in stages other than IVAE.

Improved Metered Dose Inhaler Technique When a Coordination Cap Is Used

Patients often experience problems using metered dose inhalers (MDIs), particularly poor coordination between inhalation start and dose actuation (TsIn: time difference between the start of an inhalation and the actuation of a dose), and fast peak inspiratory flow (PIF). We investigated if a coordination cap (CAP), with instruction to prolong inhalation, solved these problems. Inhalation profiles [PIF, TsIn, inhalation volume (Vi), inhalation time (Ti)] of patients with stable asthma prescribed an MDI were measured using their real-life technique (MDI). Inhalation profiles were then measured with the cap fitted (MDI+CAP). These patients were then instructed to inhale through the MDI+CAP for 5 sec, and inhalation profiles measured (MDI+CAP+TRAIN). TsIn was only measured for the MDI. Resistances of MDI and MDI+CAP were 0.0135 and 0.0243 (cm H2O)(½)/(L/min), respectively. Seventy-one patients were evaluated, with mean [standard deviation (SD)] forced expiratory volume over 1 sec % predicted normal of 78.3% (21.0). Following MDI, MDI+CAP, and MDI+CAP+TRAIN: mean (SD) PIF was 155.6 (61.5), 112.3 (48.4), and 73.8 (34.9) L/min, respectively (p<0.001); mean (SD) Ti was 1.60 (0.60), 1.92 (0.80), and 2.99 (1.03) sec, respectively (p<0.001); and Vi was similar between stages. Twelve patients used a slow flow with the MDI alone, but only two of these patients demonstrated good coordination. With the cap in place (which ensures good coordination), the number of patients using a slow flow increased to 25 for MDI+CAP and to 50 following MDI+CAP+TRAIN. The cap with its effect of increasing resistance to airflow combined with the instruction to prolong inhalation time significantly decreased the inhalation flow.

A real-time hyper-accuracy integrative approach to peak identification using lifting-based wavelet and Gaussian model for field mobile mass spectrometer

Field mobile mass spectrometer is pivotal apparatus for real-time qualitative and quantitative analyses of chemical substances in situ environment pollution detection. To solve spectrum peak signal interfered by complicated noise, and to recognize irregular peak shape as well as quick monitoring, a real-time denoising and hyper-accuracy peak identification integrative approach for field mobile mass spectrometer using lifting-based wavelet transform (LWT) and Gaussian model has been developed. First, LWT was applied to eliminate the noise and to search for mass peak parameters in raw spectral peak data. Then, fitting the irregular mass peaks with Gaussian multi-peaks, a regular spectrum signal was obtained for further processing. Both of synthetic and apparatus experiment results show that LWT is a fast and effective denoising and peak identification method and retained the original peak features. The denoising effect (SNR/RMSE) by LWT was superior to Savitzky–Golay method used widely by experimental mass spectrometer, and the processing time was shortened obviously. Moreover integrated with Gaussian fitting algorithm, the peak parameters (the peak area A, centroid c, and half peak's width w) had been optimized. As the result, qualitative and quantitative accuracies of FMMS increased consequently. In addition, the approach achieved data compression.

Dysmyelination of Auditory Afferent Axons Increases the Jitter of Action Potential Timing during High-Frequency Firing

Auditory neuropathies are linked to loss of temporal acuity of sound-evoked signals, which may be related to myelin loss. However, it is not known how myelin loss affects the waveform and temporal precision of action potentials (APs) in auditory CNS nerve terminals. Here we investigated the excitability of the calyx of Held nerve terminal in dysmyelinated auditory brainstems using the Long-Evans Shaker (LES) rat, a spontaneous mutant where compact myelin wrapping does not occur due to a genetic deletion of myelin basic protein. We found at relatively mature postnatal ages (15-17 d after birth) LES rat calyces showed prolonged spike latencies, indicative of a threefold reduction in the AP propagation velocity. Furthermore, LES rat afferent fiber-evoked APs showed a pronounced loss of temporal precision, even at low stimulation frequencies (10 Hz). While normal calyces were able to fire APs without failures at impressive rates of up to 1 kHz, LES calyces were unable to do so. Direct recordings of the presynaptic calyx terminal AP waveform revealed that myelin loss does not affect the AP spike upstroke and downstroke kinetics, but dysmyelination reduces the after-depolarization and enhances the fast after-hyperpolarization peak following the AP spike in the LES rat. Together these findings show that proper myelination is essential not only for fast AP propagation, but also for precise presynaptic AP firing that minimizes both spike jitter and failures, two characteristics critically important for the accurate processing of sound signals in the auditory brainstem.

Dynamical Properties of Glass Transition in n-Propanol

Temperature dependence of dynamical properties related to α-relaxation, fast relaxation and boson peak was studied in the liquid-glass trasntion of n-propanol. The depolarized Raman scattering spectra show the remarkable temperature variation related to the fast relaxation and boson peak. While as to the temperature dependence of internal Raman bands higher than 100cm−1, no remarkable change was observed with the exception of the O-H stretching vibrational band. This band reflects inter-molecular hydrogen bonds and marked softening was observed on cooling. The temperature dependence of α-relaxation was studied by broadband dielectric measurements from 100mHz to 10MHz. It is found that the temperature dependence of the relaxation frequency obeys Vogel-Fulcher-Tammann law. The temperature dependence of the fast relaxation was also studied through viscoelastic coupling to longitudinal acoustic phonon by polarized Brillouin scattering. This relaxation is much higher than a-relaxation.

Real-time automated spectral assessment of the BOLD response for neurofeedback at 3 and 7 T

Echo-planar imaging is the dominant functional MRI data acquisition scheme for evaluating the BOLD signal. To date, it remains the only approach providing neurofeedback from spatially localized brain activity. Real-time functional single-voxel proton spectroscopy (fSVPS) may be an alternative for spatially specific BOLD neurofeedback at 7T because it allows for a precise estimation of the local T2* signal, EPI-specific artifacts may be avoided, and the signal contrast may increase. In order to explore and optimize this alternative neurofeedback approach, we tested fully automated real-time fSVPS spectral estimation procedures to approximate T2* BOLD signal changes from the unsuppressed water peak, i.e. lorentzian non-linear complex spectral fit (LNLCSF) in frequency and frequency-time domain. The proposed approaches do not require additional spectroscopic localizers in contrast to conventional T2* approximation based on linear regression of the free induction decay (FID). For methods comparison, we evaluated quality measures for signals from the motor and the visual cortex as well as a real-time feedback condition at high (3T) and at ultra-high (7T) magnetic field strengths. Using these methods, we achieved reliable and fast water peak spectral parameter estimations. At 7T, we observed an absolute increase of spectra line narrowing due to the BOLD effect, but quality measures did not improve due to artifactual line broadening. Overall, the automated fSVPS approach can be used to assess dynamic spectral changes in real-time, and to provide localized T2* neurofeedback at 3 and 7T.

Variable column length method development strategy for amino acid analysis in serum samples of neonates with metabolic disorders

Accurate quantitative analysis of amino acids forms an important part of targeted metabolic profiling as deviations from normal amino acid profiles can be indicative of several inborn metabolic disorders. A variable-length method development strategy for HPLC analysis on superficially porous particle columns using UV detection is proposed for the separation of 21 primary amino acids. This strategy consists of the evaluation of a large set of gradient and mobile phase compositions on short columns with different stationary phase properties to rapidly determine the best separation conditions leading to the highest number of separated peaks. These conditions are subsequently used to optimize the separation on a longer column length benefitting from its higher separation performance. A minimum critical resolution of 2.0 and a maximum analysis time of 10min were imposed to allow for accurate, robust and rapid quantitation of all amino acids over a large linear range. For amino acids playing a key role in commonly encountered amino acid and urea cycle disorders, a minimum critical resolution of 2.5 was pursued. Mass spectrometry was used for fast peak tracking during the method development procedure. It was demonstrated that the retention behavior of the studied amino acids is more pressure than temperature dependent. This allowed performing the entire method development strategy at the same maximum pressure on all column lengths, while preserving the retention profile, resulting in a significant time profit for the initial scouting runs. The applicability of the method was demonstrated by analyzing serum samples of several neonates diagnosed with metabolic disorders such as maple syrup urine disorder, phenylketonuria and citrullinemia.

Comparative study of radiation dose and image noise between single-source fast kilo voltage peak switching technique and conventional mode on abdominal CT

Objective To investigate the radiation dose and image noise of abdominal CT with spectral imaging and conventional scan mode. Methods This was a retrospective study.The first part of this study was a phantom study.A standard quality assessment phantom was scanned with gemstone spectral imaging mode and conventional helical mode using 120 k Vp with different m As.A regression function for the m As between conventional scan mode and spectral imaging mode was obtained.According to the regression function,the m As on 120 k Vp corresponding to different gemstone spectral imaging protocol were calculated.The second part of this study was a clinical study.Twenty-two patients who underwent contrast enhanced abdominal CT scanning were included.The pre-contrast CT was scanned by a conventional mode with automatic exposure control technique.According to the m As of pre-contrast scan,corresponding spectral imaging parameters were selected for the portal venous phase of post-contrast scan.Five sets of images with 5 mm slice thickness were reconstructed,with 65 keV monochromatic image for spectral imaging and FBP,20%, 40% and 60% ASIR image for conventional imaging respectively.Image noise was measured on hepatic parenchyma and urinary bladder for each set of image.Radiation dose and image noise were compared between CT spectral imaging and conventional imaging with paired t-test. Results No significant differences were found for the CTDIvol[ (13.8±4.8) mGy versus (14.0±7.0) mGy] and DLP[ (691.1±274.2) mGy·cm versus (678.8±385.0) mGy·cm] between CT spectral imaging and conventional imaging.Monochromatic image (65 keV) by spectral imaging[ (7.6±1.4) HU for hepatic parenchyma and (9.1±1.3) HU for urinary bladder] had equal image noise with 40% ASIR[hepatic parenchyma: (7.8±0.7) HU]and 20% ASIR[urinary bladder: (9.2±1.2) HU]and lower image noise than FBP image[ (10.4±1.0) HU for hepatic parenchyma and (10.5±1.3) HU for urinary bladder]by conventional imaging. Conclusions The radiation dose of CT spectral imaging and conventional CT scan is equivalent with spectral imaging parameters appropriately selected.Monochromatic image (65 keV) by CT spectral imaging has lower image noise than FBP image,and same image noise with 40% ASIR (hepatic parenchyma) and 20% ASIR (urinary bladder) by conventional imaging. Key words: Tomography,X-ray computed; Radiation Dosage; Comparative study

Pharmacokinetic Alteration of 99mTc-MAG3 using Serum Protein Binding Displacement Method

When a radiopharmaceutical is simultaneously administered with a medicine that has high affinity for the same plasma protein, the radiopharmaceutical is released at higher concentrations in blood, leading to enhanced transfer into target tissues. This is known as the serum protein binding displacement method. In this study, we investigated the pharmacokinetic alteration of technetium-99m-labeled mercaptoacetylglycylglycylglycine ((99m)Tc-MAG3) using the serum protein binding displacement method. Rat and human serum protein binding rates of (99m)Tc-MAG3 were measured by ultrafiltration with or without displacers of human serum albumin (HSA) binding sites I and II (200μM and 400μM loading). Male Wistar rats were injected with (99m)Tc-MAG3 (740kBq/0.3mL saline) via the tail vein, and biodistribution was assessed at 2, 5, 10 and 15min. Dynamic whole-body images were obtained for (99m)Tc-MAG3 (11.1MBq/0.3mL saline)-injected rats, with or without HSA displacers. (99m)Tc-MAG3 strongly bound to HSA (87.37%±2.13%). Using HSA site I displacers, the free fraction of (99m)Tc-MAG3 increased significantly (1.20 to 1.47 times) when compared with controls. For biodistribution and imaging, rapid blood clearance was observed with bucolome (BCL) loading, which is an HSA site I displacer. With BCL loading, peak times for rat renograms were respectively shifted from 240s to 110s, and from 170s to 120s. We found that (99m)Tc-MAG3 bound to the HSA binding site I. It was confirmed that pharmacokinetic distribution of (99m)Tc-MAG3 is altered by presence of BCL, which leads to increases in the free fraction of (99m)Tc-MAG3, and BCL produced rapid blood clearance and fast peak times on rat renograms. The serum protein binding displacement method using (99m)Tc-MAG3 and BCL, a safe displacer for humans, may be applicable to clinical study and lead to better diagnostic images with shorter waiting times and lower radiation doses for patients.

Effect of Cholesterol Depletion on the Pore Dilation of TRPV1

The TRPV1 ion channel is expressed in nociceptors, where pharmacological modulation of its function may offer a means of alleviating pain and neurogenic inflammation processes in the human body. The aim of this study was to investigate the effects of cholesterol depletion of the cell on ion-permeability of the TRPV1 ion channel. The ion-permeability properties of TRPV1 were assessed using whole-cell patch-clamp and YO-PRO uptake rate studies on a Chinese hamster ovary (CHO) cell line expressing this ion channel. Prolonged capsaicin-induced activation of TRPV1 with N-methyl-D-glucamine (NMDG) as the sole extracellular cation, generated a biphasic current which included an initial outward current followed by an inward current. Similarly, prolonged proton-activation (pH 5.5) of TRPV1 under hypocalcemic conditions also generated a biphasic current including a fast initial current peak followed by a larger second one. Patch-clamp recordings of reversal potentials of TRPV1 revealed an increase of the ion-permeability for NMDG during prolonged activation of this ion channel under hypocalcemic conditions. Our findings show that cholesterol depletion inhibited both the second current, and the increase in ion-permeability of the TRPV1 channel, resulting from sustained agonist-activation with capsaicin and protons (pH 5.5). These results were confirmed with YO-PRO uptake rate studies using laser scanning confocal microscopy, where cholesterol depletion was found to decrease TRPV1 mediated uptake rates of YO-PRO. Hence, these results propose a novel mechanism by which cellular cholesterol depletion modulates the function of TRPV1, which may constitute a novel approach for treatment of neurogenic pain.

10 Gb/s Burst-Mode Transimpedance Preamplifier in 0.13µm CMOS Technology

A 10Gbit/s burst-mode transimpedance preamplifier is described. Regulated cascade (RGC) TIA core with variable gain, fast response peak detector, single-to-differential and output buffer are included, providing auto-gain-control and threshold extraction functions. The burst-mode preamplifier is implemented by 0.13µm CMOS technology, presents a high gain of 67.9dB with a 3-dB bandwidth of 6.92GHz and a low gain of 57.4dB with a 3-dB bandwidth of 8.60GHz with a settling time less than 20ns.

Method for in situ measurements of water, sediment and phosphorous transport in the upper soil profile

Research on transport processes involved in P losses by subsurface flow, including artificial drainage, is becoming increasingly important. An improved understanding of the processes involved in sediment detachment and P mobility in the soil profile is needed in order to develop proper management strategies for P control. The objective of this article is to present the development of a field lysimeter technique, and a complementary laboratory pinhole test on undisturbed soil samples, that can be used to assess rates and mechanisms involved in water, sediment and phosphorus transport in the upper soil profile at different rainfall intensities. The study, performed on a silty clay, consisted of three parts: (1) pre-test of a new field lysimeter approach with the aim to observe water flow patterns and difficulties related to preparation and set-up, (2) evaluation of the improved field lysimeter methodology, which consisted of a rain simulator above ground, the soil profile through which the applied water percolated, and a collection tray at 40–50 cm depth from which the drain water and sediment was sampled, (3) evaluation and development of the pinhole test for assessing soil resistance to internal erosion. The pre-tests gave promising results and the improved field lysimeter showed interesting temporal responses, at two consecutive rain simulation intensities, in outflow rates of water, bromide, lithium, total P and dissolved P. The pinhole test was run on undisturbed samples with three different water contents and at three different applied positive pressure heads and showed fast peaks in turbidity following start of each run. Combining measurements from the in situ field lysimeter and pinhole approaches presented in this article has the potential to be valuable in detecting critical parameters that control the processes leading to subsurface leaching of P to deeper soil layers.

HSQC spectral based similarity matching of compounds using nearest neighbours and a fast discrete genetic algorithm

HSQC spectra are routinely acquired for chemical structure analysis based on hydrogen and carbon chemical environments. Two fast HSQC peak matching algorithms have been developed; a nearest neighbour approach and a probabilistic method based on an existing discrete genetic algorithm. Both of these techniques are intended to find HSQC spectra matches that supplement information generated by established molecular fingerprint methods. Our results are compared to those calculated using a specific implementation of molecular fingerprints. The nearest neighbour and genetic algorithm-based methods ranked highly particular structures missed by molecular fingerprints. Our analysis shows that by complementing molecular fingerprint matches with our findings, a comprehensive list of matches can be identified. The refined list of compounds could be used to improve the quality of compounds used in screening libraries in the pharmaceutical industry.

Along‐shelf current variability on the Catalan inner‐shelf (NW Mediterranean)

We examine the circulation over the inner‐shelf of the Catalan Sea using observations of currents obtained from three Acoustic Doppler Current Profilers (two at 24 m and one at 50 m) during March–April 2011. The along‐shelf current fluctuations during that period are mainly controlled by local wind stress on short time scales and by remote pressure gradients on synoptic time scales. Different forcing mechanisms are involved in the along‐shelf momentum balance. During storm conditions, wind stress, sea level gradients and the nonlinear terms dominate the balance. During weak wind conditions, the momentum balance is controlled by the pressure gradient, while during periods of moderate wind in the presence of considerable stratification, the balance is established between the Coriolis and wind stress terms. Vertical variations of velocity are affected by the strong observed density gradient. The increased vertical shear is accompanied by the development of stratified conditions due to local heating when the wind is not able to counteract (and break) stratification. The occasional influence of the Besòs River plume is observed in time scales of hours to days in a limited area in near the city of Barcelona. The area affected by the plume depends on the vertical extent of the fresher layer, the fast river discharge peak, and the relaxation of cross‐shore velocities after northeast storm events. This contribution provides a first interpretation of the inner‐shelf dynamics in the Catalan Sea.

Are There Any Left-Right Asymmetries in Saccade Parameters? Examination of Latency, Gain, and Peak Velocity

Hemispheric specialization in saccadic control is still under debate. Here we examine the latency, gain, and peak velocity of reactive and voluntary leftward and rightward saccades to assess the respective roles of eye and hand dominance. Participants with contrasting hand and eye dominance were asked to make saccades toward a target displayed at 5°, 10°, or 15° left or right of the central fixation point. In separate sessions, reactive and voluntary saccades were elicited by Gap-200, Gap-0, Overlap-600, and Antisaccade procedures. Left-right asymmetries were not found in saccade latencies but appeared in saccade gain and peak velocity. Regardless of the dominant hand, saccades directed to the ipsilateral side relative to the dominant eye had larger amplitudes and faster peak velocities. Left-right asymmetries can be explained by naso-temporal differences for some subjects and by eye dominance for others. Further investigations are needed to examine saccadic parameters more systematically in relation to eye dominance. Indeed, any method that allows one to determine ocular dominance from objective measures based on saccade parameters should greatly benefit clinical applications, such as monovision surgery.

Fast Elastic Peak Detection for Mass Spectrometry Data Mining

We study a data mining problem concerning the elastic peak detection in 2D liquid chromatography-mass spectrometry (LC-MS) data. These data can be modeled as time series, in which the X-axis represents time points and the Y-axis represents intensity values. A peak occurs in a set of 2D LC-MS data when the sum of the intensity values in a sliding time window exceeds a user-determined threshold. The elastic peak detection problem is to locate all peaks across multiple window sizes of interest in the data set. We propose a new data structure, called a Shifted Aggregation Tree or AggTree for short, and use the data structure to find the different peaks. Our method, called PeakID, solves the elastic peak detection problem in 2D LC-MS data yielding neither false positives nor false negatives. The method works by first constructing an AggTree in a bottom-up manner from the given data set, and then searching the AggTree for the peaks in a top-down manner. We describe a state-space algorithm for finding the topology and structure of an efficient AggTree to be used by PeakID. Our experimental results demonstrate the superiority of the proposed method over other methods on both synthetic and real-world data.