Feedback linearization control for uncertain nonlinear systems via generative adversarial networks

This article presents a novel approach to leverage generative adversarial networks(GANs) techniques to learn a feedback linearization controller(FLC) for a class of uncertain nonlinear systems. By estimating uncertainty through the adversarial process, where ground truth samples are exclusively obtained from a predefined integral model, the feedback linearization controller, learned through a minimax two-player optimization framework, enhances the reference tracking performance of the input-output uncertain nonlinear system. Furthermore, we provide theoretical guarantee of convergence and stability, demonstrating the safe recovery of robust FLC. We also address the common challenge of mode collapse in GANs training through the strict convexity of our synthesized generator structure and an enhanced adversarial loss. Comprehensive simulations and practical experiments are conducted to underscore the superiority and efficacy of our proposed approach.

Homogeneous and heterogeneous atmospheric ozonolysis of chlorobenzene:Mechanism, kinetics and ecotoxicity assessment

The reactions between chlorobenzene(CB) and ozone have been studied comprehensively in this paper. Chlorobenzene is a commonly found chlorinated aromatic volatile organic compound(VOC), and its emission into the atmosphere can cause harm to the ecosystem and human health. The frequent occurrence of mineral particles from sandstorms exerts a significant influence on the atmospheric chemistry of the troposphere. Mineral particles are abundant in SiO2 and Al2O3 content. Therefore, we investigated the homogeneous and heterogeneous reaction processes of CB and ozone in the atmosphere by using density functional theory (DFT) method at the M06-2X/6-311++g(3df,2p)//M06-2X/6-31+g(d,p) level. The atmospheric fate, reaction rate and toxicity evaluation of CB ozonation were studied in the gas-phase section. Toxicity evaluation results showed that ozonation of CB could effectively reduce its toxicity. For the heterogeneous process, we simulated three types of SiO2 clusters and nine types of (Al2O3)n clusters, and studied the configurations of CB adsorbed on the cluster surfaces. We found that adsorption of CB on the SiO2 clusters was achieved through hydrogen bonding, while adsorption of CB on the Al2O3 clusters was achieved through both hydrogen bonding and metal bonding. The energy for CB adsorption on the (Al2O3)n cluster surface was higher than that for the SixOy(OH)z cluster surface, and both types of clusters exhibited efficient adsorption of CB. As the SixOy(OH)z clusters grew larger, the rates for the reactions between O3 and CB increased. CB travelled long distances along the Al2O3 clusters, leading to an extended influence range.

Develop and Evaluate a Dose Calculation Strategy Using Electron Density Maps from Spectral CT

PURPOSE/OBJECTIVE(S)

The conventional method of estimating relative electron density using Hounsfield Units (HUs) is prone to errors resulting from various factors such as energy spectrum, exposure, scanner/patient conditions, etc. Specific calibration is needed for each acquisition protocol. To overcome these limitations, dual energy CT has been extensively researched for its accuracy in dose calculation using tube potential switching techniques. A dual layer design offers a different approach to acquire spectral images using single data acquisitions. This study aims to develop and evaluate a dose calculation method using electron density maps generated directly from a dual layer detector scanner.

MATERIALS/METHODS

A phantom with tissue equivalent inserts was scanned using different scanner configurations on a dual layer detector scanner. The electron density of 17 inserts ranged from 0.668 - 5.663 × 1023 m-23. The energy dependent attenuation curves were generated and translated into values of Compton and photoelectric components, which were used to calculate ED values. The ED values were compared to normal values provided by the vendor for each insert. The generated ED maps were normalized to the ED of water and used as the input for dose calculations without CT images. Dosimetry plans were generated on the phantom for two different field sizes (10 × 10 cm2 and 3 × 3 cm2) at gantry angles of 0 and 90 degrees using a 6 MV Monte Carlo engine. The dose distributions were compared between the conventional HU to ED calibration approach with CT images and the direct calculation using the calculated ED map.

RESULTS

The results showed that compared to the conventional HU to ED map, the ED map generated from spectral CT had a relative ED that was about 0.02 lower and was more uniform, with smaller standard deviations. The ED map was closer to the nominal value in low-density regions, while the HU converted ED map was closer to the nominal value in high-density regions. The dose distributions between the two ED approaches were almost identical, with a maximum deviation of around 1% for both field sizes at deeper depths.

CONCLUSION

In conclusion, a dual layer detector scanner can provide an accurate estimation of ED maps. We showed that the dose calculation using the generated ED map is highly accurate using a phantom. This method provides an alternative strategy for dose calculation that eliminates the need for HU to ED calibration and enables the use of the ED map directly.

Preparation of g-C3N4/TCNQ Composite and Photocatalytic Degradation of Pefloxacin

g-C₃N₄ and g-C₃N₄/TCNQ composites with different doping levels were prepared using the copolymerization thermal method with melamine as a precursor. XRD, FT-IR, SEM, TEM, DRS, PL, and I-T characterized them. The composites were successfully prepared in this study. The photocatalytic degradation of pefloxacin (PEF), enrofloxacin (ciprofloxacin), and ciprofloxacin (ciprofloxacin) under visible light (λ > 550 nm) showed that the composite material had the best degradation effect on PEF. When TCNQ doping is 20 mg and catalyst dosage is 50 mg, the catalytic effect is the best, and the degradation rate reaches 91.6%, k = 0.0111 min^-1, which is four times that of g-C₃N₄. Repeated experiments found that the cyclic stability of the g-C₃N₄/TCNQ composite was good. The XRD images were almost unchanged after five reactions. The radical capture experiments revealed that ·O^2- was the main active species in the g-C₃N₄/TCNQ catalytic system, and h⁺ also played a role in PEF degradation. And the possible mechanism for PEF degradation was speculated.

PSS-dispersed dopamine triggered formation of PAA adhesive hydrogel as flexible wearable sensors

Catechol-based hydrogels have good adhesion properties; however, since the concentration of catechol is low and it can be easily oxidized to quinone, the adhesion performance of the hydrogels is reduced, which limits their application as self-adhesive flexible wearable sensors. In this work, a dopamine: poly(sodium 4-styrenesulfonate) (DA:PSS)-initiated strategy was proposed to construct adhesive hydrogels, where the semiquinone radicals present in DA:PSS were used to initiate radical polymerization to obtain the DA:PSS/poly(acrylic acid) (DA:PSS/PAA) hydrogel. This hydrogel exhibited good stretchability and adhesion with various substrates. We observed that, even after exposure to air for 21 days under certain relative humidity (76%), the catechol groups hardly oxidized and the DA:PSS/PAA hydrogel presented good adhesion. The DA:PSS/PAA hydrogel also showed good electrical conductivity and fast response ability. Thus, the general strategy of triggering monomer polymerization to form hydrogels based on the semiquinone radical present in DA:PSS offers great potential for their application in flexible electronic devices and wearable sensors.

Carbon price forecasting: a novel deep learning approach

Carbon emission trading market promotes carbon emission reduction effectively. Accurate carbon price forecasting is crucial for relevant policy makers and investors. However, due to the non-linearity, uncertainty, and complexity of carbon prices, the current predication models fail to predict carbon prices accurately. In this paper, an advanced deep neural network model named TCN-Seq2Seq is proposed to forecast carbon prices. The novelty of the proposed model focuses on the "sequence to sequence" layout to learn temporal data dependencies using only fully convolutional layers. Being provided with parallel training for fewer parameters, TCN-Seq2Seq forecasting model is more suitable for small carbon price dataset in few-shot learning way. Qualitatively and quantitatively, we find that the proposed framework consistently and significantly outperforms traditional statistical forecasting models and state-of-the-art deep learning prediction model with respect to predictive ability and robustness. Particularly, our proposed model achieves forecasting accuracy with the highest DA value (0.9697), the lowest MAPE value (0.0027), and the lowest RMSE value (0.0149), showing superior prediction performance compared with the traditional statistical forecasting models. The accuracy of carbon price forecasting gives insight to policy makers and carbon market investors.

Imaging features of primary mucinous adenocarcinoma of bladder outlet and urethra: a case report and literature review

Background

Primary bladder adenocarcinoma (PBA) only accounts for 2% of primary bladder cancers. PBA symptoms vary according to the volume, location, and the metastasis of the tumor. The most common symptoms include suprapubic pain, hematuria, dysuria, and bladder irritation. In the initial stage, the diagnosis of PBA is possibly delayed due to the lack of obvious symptoms. When diagnosed, up to 40% of patients are reported to have metastatic disease. PBA can occur anywhere in the bladder, especially the bottom, neck, and roof. However, the mass at the bladder outlet and urethra is a rare presentation of PBA. Through this rare case, when clinicians encounter similar patients, they can have richer ideas for diagnosis and treatment, which is helpful for the timely diagnosis and effective treatment.

Case Description

A 62-year-old female was referred to an outpatient urology surgery service due to a 1-year history of narrowing of the urinary route and difficulties in urination. No significant abnormalities were found in other surgical examinations, and the patient denied having a genetic history or similar history in her family. Ultrasonography revealed a hypoechoic mass of 6.5 cm × 3.8 cm × 4.4 cm at the bladder outlet and urethra. Computed tomography (CT) plain scan and enhancing scan displayed that the wall of bladder was thickened, and soft tissue density was seen at the bladder outlet and urethra with slight enhancement and an unclear partial boundary. The mass was confirmed to be PBA.

Conclusions

Primary mucinous adenocarcinoma of bladder usually detected in the posterior wall and trigone, but at the bladder outlet and urethra was rare. In this report, Imaging examination showed that the mass was located at the bladder outlet and urethra, and was finally confirmed by surgery. Due to the location of the growth, our patient’s only symptoms were dysuria and urinary tract thinning, without hematuria, suprapubic pain, or bladder irritation. Timely diagnosis and treatment of this case depend on the findings of imaging examination. We describe the imaging features of this rare disease entity and the relevant literature review.

[Combined resection of thoracic and abdominal organ clusters: a series of 50 cases]

Objective: To examine the technique and effect of combined thoracic and abdominal organ clusters resection. Methods: From February 2019 to August 2021, totally 50 cases of combined thoracoabdominal organ cluster resection were completed at Transplant Medical Center, the Second Affiliated Hospital of Guangxi Medical University from donation after brain death donors. There were 47 males and 3 females, aging (34.8±12.3) years (range: 5 to 55 years). The length of hospital stay(M(IQR)) was 4(4) days (range: 2 to 43 days), the length of tube time was 4(2) days (range: 1 to 43 days). Through the midsternal incision and the abdominal grand cross incision, the cold perfusion was performing simultaneously when the perfusion lines of each target organ was established respectively. The combined resection was performed with the diaphragm as the boundary and the organ cluster as the unit. The heart and lung were separated on site and sent to the transplant hospital, and the abdominal organ cluster was directly preserved and returned to our hospital for further separation and repair. Results: Totaly 21 hearts, 47 pairs of lungs, 49 livers, 47 pairs of kidneys and 11 pancreas were harvested by this surgical treatment. The resection time was (32.6±6.5) minutes (range: 19 to 50 minutes), with no hot ischemia time. There was no accidental injury that affected organ quality and function. Heart transplantation was performed in 17 cases, combined heart-kidney transplantation in 2 cases, double lung transplantation in 43 cases, single lung transplantation in 6 cases, liver transplantation in 41 cases, combined liver-pancreas-duodenal cluster transplantation in 1 case, combined liver-kidney transplantation in 3 cases, combined pancreas-kidney transplantation in 9 cases, and kidney transplantation in 74 cases. Conclusion: Simultaneous perfusion and combined resection of thoracic and abdominal organ clusters for donation after brain death donors are feasible and effective.

Targeting Induced Local Lesions in the Wheat DEMETER and DRE2 Genes, Responsible for Transcriptional Derepression of Wheat Gluten Proteins in the Developing Endosperm

Wheat is a major source of energy and nutrition worldwide, but it is also a primary cause of frequent diet-induced health issues, specifically celiac disease, for which the only effective therapy so far is strict dietary abstinence from gluten-containing grains. Wheat gluten proteins are grouped into two major categories: high-molecular-weight glutenin subunits (HMWgs), vital for mixing and baking properties, and gliadins plus low-molecular-weight glutenin subunits (LMWgs) that contain the overwhelming majority of celiac-causing epitopes. We put forth a hypothesis that eliminating gliadins and LMWgs while retaining HMWgs might allow the development of reduced-immunogenicity wheat genotypes relevant to most gluten-sensitive individuals. This hypothesis stems from the knowledge that the molecular structures and regulatory mechanisms of the genes encoding the two groups of gluten proteins are quite different, and blocking one group's transcription, without affecting the other's, is possible. The genes for gliadins and LMWgs have to be de-methylated by 5-methylcytosine DNA glycosylase/lyase (DEMETER) and an iron-sulfur (Fe-S) cluster biogenesis enzyme (DRE2) early during endosperm development to permit their transcription. In this study, a TILLING (Targeting Induced Local Lesions IN Genomes) approach was undertaken to identify mutations in the homoeologous DEMETER (DME) and DRE2 genes in common and durum wheat. Lines with mutations in these genes were obtained that displayed reduced content of immunogenic gluten proteins while retaining essential baking properties. Although our data at first glance suggest new possibilities for treating celiac disease and are therefore of medical and agronomical interest, it also shows that inducing mutations in the DME and DRE2 genes analyzed here affected pollen viability and germination. Hence there is a need to develop other approaches in the future to overcome this undesired effect.

Directed-Mutagenesis of Flavobacterium meningosepticum Prolyl-Oligopeptidase and a Glutamine-Specific Endopeptidase From Barley

Wheat gluten proteins are the known cause of celiac disease. The repetitive tracts of proline and glutamine residues in these proteins make them exceptionally resilient to digestion in the gastrointestinal tract. These indigested peptides trigger immune reactions in susceptible individuals, which could be either an allergic reaction or celiac disease. Gluten exclusion diet is the only approved remedy for such disorders. Recently, a combination of a glutamine specific endoprotease from barley (EP-B2), and a prolyl endopeptidase from Flavobacterium meningosepticum (Fm-PEP), when expressed in the wheat endosperm, were shown to reasonably detoxify immunogenic gluten peptides under simulated gastrointestinal conditions. However useful, these "glutenases" are limited in application due to their denaturation at high temperatures, which most of the food processes require. Variants of these enzymes from thermophilic organisms exist, but cannot be applied directly due to their optimum activity at temperatures higher than 37°C. Though, these enzymes can serve as a reference to guide the evolution of peptidases of mesophilic origin toward thermostability. Therefore, a sequence guided site-saturation mutagenesis approach was used here to introduce mutations in the genes encoding Fm-PEP and EP-B2. A thermostable variant of Fm-PEP capable of surviving temperatures up to 90°C and EP-B2 variant with a thermostability of up 60°C were identified using this approach. However, the level of thermostability achieved is not sufficient; the present study has provided evidence that the thermostability of glutenases can be improved. And this pilot study has paved the way for more detailed structural studies in the future to obtain variants of Fm-PEP and EP-B2 that can survive temperatures ~100°C to allow their packing in grains and use of such grains in the food industry.

Distribution of Cereal Cyst Nematodes (Heterodera avenae and H. filipjevi) in Eastern Washington State

Cereal cyst nematodes (CCN; Heterodera avenae and H. filipjevi), cause substantial worldwide yield loss in small grain cereals such as wheat, barley, and oat. H. avenae was first detected in the United States in western Oregon in 1974 and had spread to northeast Oregon by the mid-1980s. Although H. avenae was detected in eastern Washington in 1984, extensive infestations were not recognized until 2010. H. filipjevi, first detected in Oregon in 2008, was found in eastern Washington in 2014. To gain more information about the distribution of these two species, an extensive survey was undertaken in eastern Washington, and methods were developed to distinguish species using DNA sequencing of single cysts. In this study, we surveyed 356 wheat and barley fields in eastern Washington from 2007 to 2017. CCN from the infested locations were identified to species level by sequencing the ribosomal internal transcribed spacers (ITS) and/or 28S ribosomal RNA (rRNA) genes. The sequences were compared in the GenBank database in the National Center for Biotechnology Information (NCBI) to identify species. The results show that H. filipjevi is primarily confined to southern Whitman County, WA; and H. avenae has a wider distribution across the higher precipitation annual cropping area of eastern Whitman County. Knowledge of species identification is critical for deployment of host resistance as an effective means of management, since resistance genes for one species of CCN may not be effective against the other.

Genomic Regions Associated with Tolerance to Freezing Stress and Snow Mold in Winter Wheat

Plants grown through the winter are subject to selective pressures that vary with each year's unique conditions, necessitating tolerance of numerous abiotic and biotic stress factors. The objective of this study was to identify molecular markers in winter wheat (Triticum aestivum L.) associated with tolerance of two of these stresses, freezing temperatures and snow mold-a fungal disease complex active under snow cover. A population of 155 F2:5 recombinant inbred lines from a cross between soft white wheat cultivars "Finch" and "Eltan" was evaluated for snow mold tolerance in the field, and for freezing tolerance under controlled conditions. A total of 663 molecular markers was used to construct a genetic linkage map and identify marker-trait associations. One quantitative trait locus (QTL) associated with both freezing and snow mold tolerance was identified on chromosome 5A. A second, distinct, QTL associated with freezing tolerance also was found on 5A, and a third on 4B. A second QTL associated with snow mold tolerance was identified on chromosome 6B. The QTL on 5A associated with both traits was closely linked with the Fr-A2 (Frost-Resistance A2) locus; its significant association with both traits may have resulted from pleiotropic effects, or from greater low temperature tolerance enabling the plants to better defend against snow mold pathogens. The QTL on 4B associated with freezing tolerance, and the QTL on 6B associated with snow mold tolerance have not been reported previously, and may be useful in the identification of sources of tolerance for these traits.

Technical Note: Evaluation of the systematic accuracy of a frameless, multiple image modality guided, linear accelerator based stereotactic radiosurgery system

PURPOSE

To evaluate the total systematic accuracy of a frameless, image guided stereotactic radiosurgery system.

METHODS

The localization accuracy and intermodality difference was determined by delivering radiation to an end-to-end prototype phantom, in which the targets were localized using optical surface monitoring system (OSMS), electromagnetic beacon-based tracking (Calypso®), cone-beam CT, "snap-shot" planar x-ray imaging, and a robotic couch. Six IMRT plans with jaw tracking and a flattening filter free beam were used to study the dosimetric accuracy for intracranial and spinal stereotactic radiosurgery treatment.

RESULTS

End-to-end localization accuracy of the system evaluated with the end-to-end phantom was 0.5 ± 0.2 mm with a maximum deviation of 0.9 mm over 90 measurements (including jaw, MLC, and cone measurements for both auto and manual fusion) for single isocenter, single target treatment, 0.6 ± 0.4 mm for multitarget treatment with shared isocenter. Residual setup errors were within 0.1 mm for OSMS, and 0.3 mm for Calypso. Dosimetric evaluation based on absolute film dosimetry showed greater than 90% pass rate for all cases using a gamma criteria of 3%/1 mm.

CONCLUSIONS

The authors' experience demonstrates that the localization accuracy of the frameless image-guided system is comparable to robotic or invasive frame based radiosurgery systems.

[Epidemic profile of mumps in China during 2004-2013]

OBJECTIVE

To analyze the epidemiological characteristics of mumps in China from 2004 to 2013.

METHODS

Data of mump cases occurring between 2004 and 2013 were gathered from the national notifiable disease reporting system in China (excluding Hong Kong, Macao, and Taiwan); only cases classified as "final card" , laboratory confirmed, or clinical diagnosis were included. Descriptive epidemiology techniques were used to analyze features of sex, age, trends over time, and geography.

RESULTS

Average incidence of mumps between 2004 to 2013 was 24.20/100 000. Peaks were in 2011 and 2012, with incidence 33.9/100 000 (454 385/1.340 million) and 35.6/100 000 (479 518/1.347 million). Two seasonal peaks occurred regularly in years, one from April to July in the first year, and the other from November to January in the next year. During the study period, provinces with the highest incidence were Ningxia, Tibet, Xinjiang, and Guangxi; incidences were 72.1/100 000 (4 425/6.13 million), 48.5/100 000 (1 396/3 million), 51.7/100 000 (10 887/21.04 million), and 40.8/100 000 (19 179/46.99 million), respectively. Guangdong (28 078), Sichuan (21 924), Guangxi (21 616), and Zhejiang (20 000) provinces reported the highest number of mumps cases. Beijing, Tianjin, and Shanghai showed a consistently low incidence. Mumps cases occurred primarily among children aged 5-9 years, with incidence ranging from 118.2/100 000 to 281.4/100 000. In 2004-2008, the peak age was 6-8 years (174.1/100 000) and in 2009-2013, peak age was 5-7 years (234.5/100 000).

CONCLUSION

The highest incidences of mumps in China were reported in 2011 and 2012, with children of school age constituting the majority of cases.