850 research outputs found
A comparative investigation of the combined effects of pre-processing, wavelength selection and regression methods on near infrared calibration model performance
Near-infrared (NIR) spectroscopy is being widely used in various fields ranging from pharmaceutics to the food industry for analyzing chemical and physical properties of the substances concerned. Its advantages over other analytical techniques include available physical interpretation of spectral data, nondestructive nature and high speed of measurements, and little or no need for sample preparation. The successful application of NIR spectroscopy relies on three main aspects: pre-processing of spectral data to eliminate nonlinear variations due to temperature, light scattering effects and many others, selection of those wavelengths that contribute useful information, and identification of suitable calibration models using linear/nonlinear regression . Several methods have been developed for each of these three aspects and many comparative studies of different methods exist for an individual aspect or some combinations. However, there is still a lack of comparative studies for the interactions among these three aspects, which can shed light on what role each aspect plays in the calibration and how to combine various methods of each aspect together to obtain the best calibration model. This paper aims to provide such a comparative study based on four benchmark data sets using three typical pre-processing methods, namely, orthogonal signal correction (OSC), extended multiplicative signal correction (EMSC) and optical path-length estimation and correction (OPLEC); two existing wavelength selection methods, namely, stepwise forward selection (SFS) and genetic algorithm optimization combined with partial least squares regression for spectral data (GAPLSSP); four popular regression methods, namely, partial least squares (PLS), least absolute shrinkage and selection operator (LASSO), least squares support vector machine (LS-SVM), and Gaussian process regression (GPR). The comparative study indicates that, in general, pre-processing of spectral data can play a significant role in the calibration while wavelength selection plays a marginal role and the combination of certain pre-processing, wavelength selection, and nonlinear regression methods can achieve superior performance over traditional linear regression-based calibration
Metaverse in Education: Vision, Opportunities, and Challenges
Traditional education has been updated with the development of information
technology in human history. Within big data and cyber-physical systems, the
Metaverse has generated strong interest in various applications (e.g.,
entertainment, business, and cultural travel) over the last decade. As a novel
social work idea, the Metaverse consists of many kinds of technologies, e.g.,
big data, interaction, artificial intelligence, game design, Internet
computing, Internet of Things, and blockchain. It is foreseeable that the usage
of Metaverse will contribute to educational development. However, the
architectures of the Metaverse in education are not yet mature enough. There
are many questions we should address for the Metaverse in education. To this
end, this paper aims to provide a systematic literature review of Metaverse in
education. This paper is a comprehensive survey of the Metaverse in education,
with a focus on current technologies, challenges, opportunities, and future
directions. First, we present a brief overview of the Metaverse in education,
as well as the motivation behind its integration. Then, we survey some
important characteristics for the Metaverse in education, including the
personal teaching environment and the personal learning environment. Next, we
envisage what variations of this combination will bring to education in the
future and discuss their strengths and weaknesses. We also review the
state-of-the-art case studies (including technical companies and educational
institutions) for Metaverse in education. Finally, we point out several
challenges and issues in this promising area.Comment: IEEE BigData 2022. 10 pages, 5 figures, 3 table
Spatially resolved MaNGA observations of the host galaxy of superluminous supernova 2017egm
Superluminous supernovae (SLSNe) are found predominantly in dwarf galaxies,
indicating that their progenitors have a low metallicity. However, the most
nearby SLSN to date, SN 2017egm, occurred in the spiral galaxy NGC 3191, which
has a relatively high stellar mass and correspondingly high metallicity. In
this paper, we present detailed analysis of the nearby environment of SN
2017egm using MaNGA IFU data, which provides spectral data on kiloparsec
scales. From the velocity map we find no evidence that SN 2017egm occurred
within some intervening satellite galaxy, and at the SN position most
metallicity diagnostics yield a solar and above solar metallicity (12 + log
(O/H) = 8.8-9.1). Additionally we measure a small H-alpha equivalent width (EW)
at the SN position of just 34 Angs, which is one of the lowest EWs measured at
any SLSN or Gamma-Ray Burst position, and indicative of the progenitor star
being comparatively old. We also compare the observed properties of NGC 3191
with other SLSN host galaxies. The solar-metallicity environment at the
position of SN 2017egm presents a challenge to our theoretical understanding,
and our spatially resolved spectral analysis provides further constraints on
the progenitors of SLSNe.Comment: Accepted version in ApJ Letter. Thank you for useful comment
Composite type A thymoma and diffuse large B-cell lymphoma
AbstractThe concurrent occurrence of thymoma and diffuse large B-cell lymphoma in the thymus has not been previously reported. We describe a 74-year-old man who presented with general weakness, neck lymphadenopathy, night sweats, and body weight loss. A right anterior mediastinal mass was found on computed tomography of the chest. The immunohistochemical stains AE1/AE3, CD20, CD3, and MUM-1 confirmed the different components of the mediastinal tumor. A heavy-chain gene clonality assay and light-chain gene clonality assay confirmed the B-cell clonality of the mediastinal tumor and neck lymph node. The patient had received a complete course of chemotherapy, and the result of positron emission tomography–computed tomography showed complete remission. The pathologic report of this mass revealed composite type A thymoma and diffuse large B-cell lymphoma. If concurrent or composite thymoma and lymphoma are suspected, a thorough examination of the thymoma with a combination of ancillary studies is recommended to rule out the possibility of concurrent lymphoma
Ser-634 and Ser-636 of Kaposi’s Sarcoma-Associated Herpesvirus RTA are Involved in Transactivation and are Potential Cdk9 Phosphorylation Sites
The replication and transcription activator (RTA) of Kaposi’s sarcoma-associated herpesvirus (KSHV), K-RTA, is a lytic switch protein that moderates the reactivation process of KSHV latency. By mass spectrometric analysis of affinity purified K-RTA, we showed that Thr-513 or Thr-514 was the primary in vivo phosphorylation site. Thr-513 and Thr-514 are proximal to the nuclear localization signal (527KKRK530) and were previously hypothesized to be target sites of Ser/Thr kinase hKFC. However, substitutions of Thr with Ala at 513 and 514 had no effect on K-RTA subcellular localization or transactivation activity. By contrast, replacement of Ser with Ala at Ser-634 and Ser-636 located in a Ser/Pro-rich region of K-RTA, designated as S634A/S636A, produced a polypeptide with ∼10 kDa shorter in molecular weight and reduced transactivation in a luciferase reporter assay relative to the wild type. In contrast to prediction, the decrease in molecular weight was not due to lack of phosphorylation because the overall Ser and Thr phosphorylation state in K-RTA and S634A/S636A were similar, excluding that Ser-634 or Ser-636 motif served as docking sites for consecutive phosphorylation. Interestingly, S634A/S636A lost ∼30% immuno-reactivity to MPM2, an antibody specific to pSer/pThr-Pro motif, indicating that 634SPSP637 motif was in vivo phosphorylated. By in vitro kinase assay, we showed that K-RTA is a substrate of CDK9, a Pro-directed Ser/Thr kinase central to transcriptional regulation. Importantly, the capability of K-RTA in associating with endogenous CDK9 was reduced in S634A/S636A, which suggested that Ser-634 and Ser-636 may be involved in CDK9 recruitment. In agreement, S634A/S636A mutant exhibited ∼25% reduction in KSHV lytic cycle reactivation relative to that by the wild type K-RTA. Taken together, our data propose that Ser-634 and Ser-636 of K-RTA are phosphorylated by host transcriptional kinase CDK9 and such a process contributes to a full transcriptional potency of K-RTA
AGROBEST: an efficient Agrobacterium-mediated transient expression method for versatile gene function analyses in Arabidopsis seedlings
Background: Transient gene expression via Agrobacterium-mediated DNA transfer offers a simple and fast method to analyze transgene functions. Although Arabidopsis is the most-studied model plant with powerful genetic and genomic resources, achieving highly efficient and consistent transient expression for gene function analysis in Arabidopsis remains challenging. Results: We developed a highly efficient and robust Agrobacterium-mediated transient expression system, named AGROBEST (Agrobacterium-mediated enhanced seedling transformation), which achieves versatile analysis of diverse gene functions in intact Arabidopsis seedlings. Using β-glucuronidase (GUS) as a reporter for Agrobacterium-mediated transformation assay, we show that the use of a specific disarmed Agrobacterium strain with vir gene pre-induction resulted in homogenous GUS staining in cotyledons of young Arabidopsis seedlings. Optimization with AB salts in plant culture medium buffered with acidic pH 5.5 during Agrobacterium infection greatly enhanced the transient expression levels, which were significantly higher than with two existing methods. Importantly, the optimized method conferred 100% infected seedlings with highly increased transient expression in shoots and also transformation events in roots of ~70% infected seedlings in both the immune receptor mutant efr-1 and wild-type Col-0 seedlings. Finally, we demonstrated the versatile applicability of the method for examining transcription factor action and circadian reporter-gene regulation as well as protein subcellular localization and protein–protein interactions in physiological contexts. Conclusions: AGROBEST is a simple, fast, reliable, and robust transient expression system enabling high transient expression and transformation efficiency in Arabidopsis seedlings. Demonstration of the proof-of-concept experiments elevates the transient expression technology to the level of functional studies in Arabidopsis seedlings in addition to previous applications in fluorescent protein localization and protein–protein interaction studies. In addition, AGROBEST offers a new way to dissect the molecular mechanisms involved in Agrobacterium-mediated DNA transfer
A Sampling Train for Rapid Measurement of Regional Lung Deposition
ABSTRACT An experimental system for rapid measurement of regional lung deposition of Di-2-ethylhexyl sebacate (DEHS) aerosol particles was established in the present study. The principal goal was to identify the most relevant components of the sampling train and the proper instruments to be employed. After completing the search for an optimal sampling train and instruments, a human subject test was performed. Overall, the sampling train consisted of a mouthpiece, flow meter, and particle counter. The mouthpiece was attached to a Fleisch pneumotachograph. Several TSI condensation particle counters (CPCs), a PC-LabCard and a personal computer were employed to measure and record the counts of test particles at 100 Hz. A cylinder-piston breathing machine was built to generate a series of "standard" breathing patterns. For non-human subject tests, an acrylic tube, 5 cm diameter × 60 cm length, packed with a piece of 100 ppi foam disks was used as a substitute for the human respiratory tract. The optimal sampling train was determined to be a 1TH Fleisch pneumotachograph with a CPC model 3025A because of its short response time and low flow fluctuation. A healthy non-smoking man volunteered to be the subject, and was asked to follow breathing patterns generated by a cylinder-piston breathing machine. The local deposition efficiency was calculated for 1 μm DEHS particles of each 50 cm 3 volumetric region. The deposition data showed a good agreement with previous studies. Compared to the conventional bolus system, the advantage of the rapid measurement system developed in this work is its simplicity, low exposure, and high efficiency
Ventricular divergence correlates with epicardial wavebreaks and predicts ventricular arrhythmia in isolated rabbit hearts during therapeutic hypothermia
INTRODUCTION:
High beat-to-beat morphological variation (divergence) on the ventricular electrogram during programmed ventricular stimulation (PVS) is associated with increased risk of ventricular fibrillation (VF), with unclear mechanisms. We hypothesized that ventricular divergence is associated with epicardial wavebreaks during PVS, and that it predicts VF occurrence.
METHOD AND RESULTS:
Langendorff-perfused rabbit hearts (n = 10) underwent 30-min therapeutic hypothermia (TH, 30°C), followed by a 20-min treatment with rotigaptide (300 nM), a gap junction modifier. VF inducibility was tested using burst ventricular pacing at the shortest pacing cycle length achieving 1:1 ventricular capture. Pseudo-ECG (p-ECG) and epicardial activation maps were simultaneously recorded for divergence and wavebreaks analysis, respectively. A total of 112 optical and p-ECG recordings (62 at TH, 50 at TH treated with rotigaptide) were analyzed. Adding rotigaptide reduced ventricular divergence, from 0.13±0.10 at TH to 0.09±0.07 (p = 0.018). Similarly, rotigaptide reduced the number of epicardial wavebreaks, from 0.59±0.73 at TH to 0.30±0.49 (p = 0.036). VF inducibility decreased, from 48±31% at TH to 22±32% after rotigaptide infusion (p = 0.032). Linear regression models showed that ventricular divergence correlated with epicardial wavebreaks during TH (p<0.001).
CONCLUSION:
Ventricular divergence correlated with, and might be predictive of epicardial wavebreaks during PVS at TH. Rotigaptide decreased both the ventricular divergence and epicardial wavebreaks, and reduced the probability of pacing-induced VF during TH
Downregulation of SIRT1 and GADD45G genes and left atrial fibrosis induced by right ventricular dependent pacing in a complete atrioventricular block pig model
The molecular and genetic mechanisms underlying left atrial (LA) enlargement and atrial fibrosis following right ventricular (RV) dependent pacing remain unclear. Our objective was to investigate genetic expressions in the LA of pigs subjected to RV pacing for atrioventricular block (AVB), as well as to identify the differential gene expressions affected by biventricular (BiV) pacing. We established an AVB pig model and divided the subjects into three groups: a sham control group, an RV pacing group, and a BiV pacing group. Differential expression genes (DEGs) analyses conducted through next-generation sequencing (NGS) and enrichment analyses were employed to identify genes with altered expression in the LA myocardium. The RV pacing group showed a significant increase in extracellular fibrosis in the LA myocardium compared to the control group. NGS analysis revealed suppressed expression of the sirtuin signaling pathway in the RV pacing group. Among the DEGs within this pathway, GADD45G was found to be downregulated in the RV pacing group and upregulated in the BiV pacing group. Remarkably, the BiV pacing group exhibited elevated levels of GADD45G protein. In our study, we observed significant downregulation of SIRT1 and GADD45G genes, which are associated with the sirtuin signaling pathway, in the LA myocardium of the RV pacing group when compared to the control group. Moreover, these genes, which were downregulated in the RV pacing group, displayed a noteworthy upregulation in the BiV pacing group when compared to the RV pacing group
Improved Breath Phase and Continuous Adventitious Sound Detection in Lung and Tracheal Sound Using Mixed Set Training and Domain Adaptation
Previously, we established a lung sound database, HF_Lung_V2 and proposed
convolutional bidirectional gated recurrent unit (CNN-BiGRU) models with
adequate ability for inhalation, exhalation, continuous adventitious sound
(CAS), and discontinuous adventitious sound detection in the lung sound. In
this study, we proceeded to build a tracheal sound database, HF_Tracheal_V1,
containing 11107 of 15-second tracheal sound recordings, 23087 inhalation
labels, 16728 exhalation labels, and 6874 CAS labels. The tracheal sound in
HF_Tracheal_V1 and the lung sound in HF_Lung_V2 were either combined or used
alone to train the CNN-BiGRU models for respective lung and tracheal sound
analysis. Different training strategies were investigated and compared: (1)
using full training (training from scratch) to train the lung sound models
using lung sound alone and train the tracheal sound models using tracheal sound
alone, (2) using a mixed set that contains both the lung and tracheal sound to
train the models, and (3) using domain adaptation that finetuned the
pre-trained lung sound models with the tracheal sound data and vice versa.
Results showed that the models trained only by lung sound performed poorly in
the tracheal sound analysis and vice versa. However, the mixed set training and
domain adaptation can improve the performance of exhalation and CAS detection
in the lung sound, and inhalation, exhalation, and CAS detection in the
tracheal sound compared to positive controls (lung models trained only by lung
sound and vice versa). Especially, a model derived from the mixed set training
prevails in the situation of killing two birds with one stone.Comment: To be submitted, 31 pages, 6 figures, 5 table
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