In this paper, an adaptive field-oriented induction motor drive based on the adaptation of the rotor time constant and the observation of the rotor flux linkage is presented. Since the deviation of ...motor parameters affects the accuracy of field orientation and rotor flux estimation, the adaptation mechanism is utilized to tune the rotor time constant to correct the field-oriented mechanism and the current-model based rotor flux observation. Employing the adaptive controller on field orientation, the robustness of decoupling control to the variation of rotor time constant can be obtained and the exact observation for the magnitude and the phase angle of the rotor flux can, be achieved as well. Finally, some simulation and experimental results are presented to verify its effectiveness.
α-Synuclein is critical to the pathogenesis of Parkinson's disease (PD). Few studies examined the plasma levels of α-synuclein due to the exceptionally low level of α-synuclein in plasma compared ...with cerebrospinal fluid. We aimed to investigate plasma α-synuclein in patients with PD of different disease severity.
There were total 114 participants, including 80 patients with PD and 34 controls, in the study. Participants received a complete evaluation of motor and non-motor symptoms, including cognitive function. We applied immunomagnetic reduction-based immunoassay to measure plasma levels of α-synuclein.
Plasma levels of α-synuclein were significantly higher in patients with PD compared with controls (median: 1.56 pg/mL, 95% CI 1.02 to 1.98 pg/mL vs 0.02 pg/mL, 95% CI 0.01 to 0.03 pg/mL; p<0.0001). Although there was a significant increase in plasma α-synuclein levels in PD patients with a higher Hoehn-Yahr (H-Y) stage, there was no correlation with motor symptom severity, as assessed by Unified Parkinson's Disease Rating Scale part III scores, after confounders (age, gender, and disease duration) were taken into account. However, plasma α-synuclein levels were significantly higher in PD patients with dementia (PDD) than in PD patients with mild cognitive impairment (PD-MCI) or normal cognition (0.42 pg/mL, (95% CI 0.25 to 0.93) for PD with normal cognition; 1.29 pg/mL (95% CI 0.76 to 1.93) for PD-MCI and 4.09 pg/mL (95% CI 1.99 to 6.19) for PDD, p<0.01) and were negatively correlated with Mini-Mental State Examination scores (R
-adjusted=0.3004, p<0.001), even after confounder adjustment.
Our data suggest that plasma α-synuclein level correlates with cognitive decline but not motor severity in patients with PD. Plasma α-synuclein could serve as a surrogate biomarker for patients at risk of cognitive decline.
Parkinson's disease (PD) has significant clinical overlaps with atypical parkinsonism syndromes (APS), which have a poorer treatment response and a more aggressive course than PD. We aimed to ...identify plasma biomarkers to differentiate PD from APS.
Plasma samples (
= 204) were obtained from healthy controls and from patients with PD, dementia with Lewy bodies (DLB), multiple system atrophy, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), or frontotemporal dementia (FTD) with parkinsonism (FTD-P) or without parkinsonism. We measured plasma levels of α-synuclein, total tau, p-Tau181, and amyloid beta 42 (Aβ42) by immunomagnetic reduction-based immunoassay.
Plasma α-synuclein level was significantly increased in patients with PD and APS when compared with controls and FTD without parkinsonism (
< 0.01). Total tau and p-Tau181 were significantly increased in all disease groups compared to controls, especially in patients with FTD (
< 0.01). A multivariate and receiver operating characteristic curve analysis revealed that a cut-off value for Aβ42 multiplied by p-Tau181 for discriminating patients with FTD from patients with PD and APS was 92.66 (pg/ml)
, with an area under the curve (AUC) of 0.932. An α-synuclein cut-off of 0.1977 pg/ml could separate FTD-P from FTD without parkinsonism (AUC 0.947). In patients with predominant parkinsonism, an α-synuclein cut-off of 1.388 pg/ml differentiated patients with PD from those with APS (AUC 0.87).
Our results suggest that integrated plasma biomarkers improve the differential diagnosis of PD from APS (PSP, CBD, DLB, and FTD-P).
Immunomagnetic reduction (IMR), which involves the use of antibody-functionalized magnetic nanoparticles to specifically label target biomarkers, was utilized to develop an assay for total tau ...protein in human plasma. The analytic properties of the IMR assay on tau protein were investigated. The limit of detection was found to be 0.026 pg/ml. Other properties such as Hook effect, assay linearity, dilution recovery range, reagent stability, interference test, and spiked recovery were also characterized. The ultra-sensitive IMR assay was applied to detect the plasma tau protein levels of subjects with prevalent neurodegenerative diseases, such as Alzheimer's disease (AD), mild cognitive impairment (MCI) due to AD, Parkinson's disease (PD), frontotemporal dementia (FTD) and vascular dementia (VD). The concentrations of plasma tau protein in patients with VD, PD, MCI due to AD, FTD, and AD patients were higher than that of healthy controls. Using an ROC curve analysis, the cutoff value for discriminating dementia patients from healthy controls was 17.43 pg/ml, resulting in 0.856 and 0.727 for clinical sensitivity and specificity, respectively. The area under the ROC curve was 0.908. These results imply that the IMR plasma tau assay would be useful to screen for prevalent neurodegenerative diseases.
An alternating-current magnetosusceptometer of antibody-functionalized magnetic nanoparticles (MNPs) was developed for immunomagnetic reduction (IMR). A high-sensitivity, high-critical-temperature ...superconducting quantum interference device was used in the magnetosusceptometer. Minute levels of biomarkers of early-stage neurodegeneration diseases were detectable in serum, but measuring each biomarker required approximately 4 h. Hence, an eight-channel platform was developed in this study to fit minimal screening requirements for Alzheimer's disease. Two consistent results were measured for three biomarkers, namely Aβ40, Aβ42, and tau protein, per human specimen. This paper presents the instrument configuration as well as critical characteristics, such as the low noise level variations among channels, a high signal-to-noise ratio, and the coefficient of variation for the biomarkers' IMR values. The instrument's ultrahigh sensitivity levels for the three biomarkers and the substantially shorter total measurement time in comparison with the previous single- and four-channels platforms were also demonstrated in this study. Thus, the eight-channel instrument may serve as a powerful tool for clinical high-throughput screening of Alzheimer's disease.
It is difficult to discriminate healthy subjects and patients with Parkinson disease (PD) or Parkinson disease dementia (PDD) by assaying plasma α-synuclein because the concentrations of circulating ...α-synuclein in the blood are almost the same as the low-detection limit using current immunoassays, such as enzyme-linked immunosorbent assay. In this work, an ultra-sensitive immunoassay utilizing immunomagnetic reduction (IMR) is developed. The reagent for IMR consists of magnetic nanoparticles functionalized with antibodies against α-synuclein and dispersed in pH-7.2 phosphate-buffered saline. A high-Tc superconducting-quantum-interference-device (SQUID) alternative-current magnetosusceptometer is used to measure the IMR signal of the reagent due to the association between magnetic nanoparticles and α-synuclein molecules.
According to the experimental α-synuclein concentration dependent IMR signal, the low-detection limit is 0.3 fg/ml and the dynamic range is 310 pg/ml. The preliminary results show the plasma α-synuclein for PD patients distributes from 6 to 30 fg/ml. For PDD patients, the concentration of plasma α-synuclein varies from 0.1 to 100 pg/ml. Whereas the concentration of plasma α-synuclein for healthy subjects is significantly lower than that of PD patients.
The ultra-sensitive IMR by utilizing antibody-functionalized magnetic nanoparticles and high-Tc SQUID magnetometer is promising as a method to assay plasma α-synuclein, which is a potential biomarker for discriminating patients with PD or PDD.
A highly sensitive immunoassay, the immunomagnetic reduction, is used to measure several biomarkers for plasma that is related to Alzheimer’s disease (AD). These biomarkers include Aβ-40, Aβ-42, and ...tau proteins. The samples are composed of four groups: healthy controls (n = 66), mild cognitive impairment (MCI, n = 22), very mild dementia (n = 23), and mild-to-serve dementia, all due to AD (n = 22). It is found that the concentrations of both Aβ-42 and tau protein for the healthy controls are significantly lower than those of all of the other groups. The sensitivity and the specificity of plasma Aβ-42 and tau protein in differentiating MCI from AD are all around 0.9 (0.88–0.97). However, neither plasma Aβ-42 nor tau-protein concentration is an adequate parameter to distinguish MCI from AD. A parameter is proposed, which is the product of plasma Aβ-42 and tau-protein levels, to differentiate MCI from AD. The sensitivity and specificity are found to be 0.80 and 0.82, respectively. It is concluded that the use of combined plasma biomarkers not only allows the differentiation of the healthy controls and patients with AD in both the prodromal phase and the dementia phase, but it also allows AD in the prodromal phase to be distinguished from that in the dementia phase.
Background
TDP‐43 is a promising biomarker for frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). However, studies on TDP‐43 in human biofluid are rare. In this work, the authors ...utilized an ultrasensitive technology, called immunomagnetic reduction (IMR), to develop the reagent for assaying TDP‐43.
Method
The preclinical performance characteristics of the TDP‐43 reagent, such as the standard curve, detection limits, assay linearity, dilution recovery range, assay reproducibility, spike recovery, reagent stability, and interference tests, were explored according to the CLSI guidelines. Plasma samples from normal controls (NC, n = 27) and from patients with frontotemporal dementia (FTD, n = 9), Alzheimer’s disease (AD, n = 34) and Parkinson’s disease (PD, n = 10) were collected for TDP‐43 assays using the IMR TDP‐43 reagent.
Result
The low‐detection limit of assaying TDP‐43 was 0.68 fg/ml, and the upper‐detection limit was 100 pg/ml. There was no significant interference effect when assaying TDP‐43 mixed with hemoglobin, bilirubin, intralipid, albumin, etc. The FTD patients had significantly higher levels of plasma TDP‐43 (0.419±0.193 fg/ml) compared to the NC subjects (0.163±0.097 fg/ml), AD patients (0.165±0.082 fg/ml) and PD patients (0.069±0.068 fg/ml). Through analysis of the ROC curve, the cut‐off value of plasma TDP‐43 for discriminating FTD from the other patient groups was 0.237 fg/ml, which resulted a clinical sensitivity of 0.889 and a specificity of 0.831.
Conclusion
These results demonstrate the feasibility of assaying plasma TDP‐43 to specifically identify FTD.
Burning multi-fuel, including gases, liquid fuels and coal, whose flow rates and heating values vary all the time, a typical boiler in the steel and iron plant poses a challenge to achieving optimal ...operation. The present study proposes to develop an adaptive data-driven thermal efficiency estimator of multi-fuel boilers based on statistical identification of key variables. With the available on-line efficiency model, the model-based controller is hence readily applicable to improve the boiler efficiency. Real operation data taken from two industrial boilers are used to verify the effectiveness of the proposed method. The first half part of data serves to develop statistical models while the second half part serves to be simulated as virtual plants. The application of the proposed methods improved 1.94% of the thermal efficiency of a boiler burning multi-gas and 0.73% of a boiler burning coal and multi-gas in the virtual plant simulations.
Introduction
Concentrations of plasma biomarkers associated with Alzheimer’s disease have been reported to be as low as several tens of picograms/milliliter (pg/ml). However, in assays measuring ...these biomarkers, it is likely that repeated measurements are necessary to obtain reliable values.
Methods
We performed assays as a single test or as duplicate, quadruplicate, fivefold and tenfold repeated tests, on samples spiked with different concentrations of amyloid β 1–40 (Aβ
1–40
; 1–1000 pg/ml), Aβ
1–42
(1–30,000 pg/ml) and total Tau protein (T-Tau; 0.1–1000 pg/ml), with the aim to to calculate the coefficients of variation (CVs).
Results
The results demonstrated common changes in the CVs with changes in the number of tests for a given sample: the CVs decreased with increases in the number of tests from one to ten. All CV values were distributed within the range of 0.35 to 15.5%; as such, the CV values were all lower than the acceptable value of 20%.
Conclusion
Based on this study, a single assay of Aβ
1–40
, Aβ
1–42
and T-Tau, respectively, provides reliable results in terms of the measurement of that plasma biomarker.
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