Simulation study on the oxidation performance of low-concentration methane preheating direct current catalytic oxidation plant considering thermal radiation.

In this study, the process of catalytic oxidation of methane considering radiative heat transfer was simulated using FLUENT computational software to study the effect of thermal radiation on the oxidation performance of the simulated device, and to investigate the extent to which radiative heat transfer affects the oxidation performance of the device under different operating conditions. The results show that the extent to which thermal radiation affects the oxidative performance of the equipment increases with increasing inlet temperature. When the intake temperature reaches 900K, its proportion is close to 45 %. At the same time, as the inlet gas temperature increases, the maximum reaction temperature of the oxidation unit is 1154 K, and the methane conversion rate reaches up to 89 %. The main factor affecting the oxidation performance of the unit at this time is radiation heat transfer. The extent to which thermal radiation affects the oxidative performance of the device diminishes with increasing inlet velocity. When the wind speed reaches 2 m/s, the proportion of radiative heat transfer is only 10 %, the maximum reaction temperature of the plant falls to 993 K, and the methane conversion rate drops to 68 %. At this time, the main factor affecting the oxidation performance of the plant is convective heat transfer. The influence of thermal radiation on oxidation performance gradually diminishes with an increase in intake velocity, and the proportion of radiative heat transfer decreases continuously. At methane concentrations above 1 %, the proportion of radiative heat transfer is less than 25 per cent, the maximum reaction temperature of the unit increases to 1087 K, and the methane conversion rises to 88 %. At this point, the main factor affecting the oxidation performance of the plant is convective heat transfer.

An effective transformer based on dual attention fusion for underwater image enhancement.

Underwater images suffer from color shift, low contrast, and blurred details as a result of the absorption and scattering of light in the water. Degraded quality images can significantly interfere with underwater vision tasks. The existing data-driven based underwater image enhancement methods fail to sufficiently consider the impact related to the inconsistent attenuation of spatial areas and the degradation of color channel information. In addition, the dataset used for model training is small in scale and monotonous in the scene. Therefore, our approach solves the problem from two aspects of the network architecture design and the training dataset. We proposed a fusion attention block that integrate the non-local modeling ability of the Swin Transformer block into the local modeling ability of the residual convolution layer. Importantly, it can adaptively fuse non-local and local features carrying channel attention. Moreover, we synthesize underwater images with multiple water body types and different degradations using the underwater imaging model and adjusting the degradation parameters. There are also perceptual loss functions introduced to improve image vision. Experiments on synthetic and real-world underwater images have shown that our method is superior. Thus, our network is suitable for practical applications.

Analysis of risk factors for duodenal leak after repair of a duodenal perforation.

BACKGROUND: Repairing of a duodenal perforation is a well accepted procedure, but clinically, approximately 4% of patients develop duodenal leaks after perforation repair, increasing the risk of death. We retrospectively analyzed clinical data from 168 patients at our hospital to explore risk factors for duodenal leak after perforation repair and developed a nomogram for predicting postoperative duodenal leak. METHODS: This retrospective case-control study totalled 168 patients undergoing repair of a duodenal perforation with omentopexy at the General Surgery Department, Dongnan Hospital of Xiamen University, from January 2012 to January 2022. The patients were divided into the non-leak group and the leak group. Risk factors were evaluated by analyzing the patient's sex, shock, diameter and anatomic position of the ulcer, use of NSAIDS and Glucocorticoid, history of drinking, diabetes, chronic diseases, age, time of onset of symptoms and lab tests. RESULT: One hundred fifty-six patients (92.9%) who did not develop leaks after repair of a duodenal perforation were included in the non-leak group, and 12 (7.1%) developed leaks were included in the leak group. In univariate analysis, there were significant differences between the two groups referring to age, shock, NSAIDs, albumin, and perforation size (P < 0.05). The area under the ROC curve for perforation diameter was 0.737, the p-value was 0.006, the optimal cutoff point was 11.5, sensitivity was 58.3%, and specificity was 93.6%, the positive predictive value is 41.1%, and the negative predictive value is 98.0%. In the internal validation of the performance of the nomogram, the C-index and AUC of the model were 0.896(95%CI 0.81-0.98), demonstrating that the nomogram model was well calibrated. CONCLUSION: The study discussed the risk factors for postoperative duodenal leak in patients undergoing repair of a duodenal perforation, and a nomogram was constructed to predict the leak. Future prospective studies with large sample sizes and multiple centres are needed to further elucidate the risk of duodenal leak after repair of a duodenal perforation.

Experimental study of the effects of absorbable gelatin sponge and non­absorbable polyvinyl alcohol particle material used in transcatheter arterial embolization on liver tissues.

Hepatic trauma is a leading cause of death in major abdominal trauma, and transcatheter arterial embolization has been widely used to treat it. However, there is limited research on whether absorbable gelatin sponge (AGS) and non-absorbable polyvinyl alcohol particles (PVA) have different effects on liver tissue, making it an important area of exploration. The present study investigated this issue using animal experiments by performing transhepatic arterial embolization with AGS and PVA. The effects on normal liver tissue in rabbits were examined by detecting liver function and inflammatory indexes, conducting histopathological examination, and using western blotting to detect apoptotic proteins. There were significant differences between the AGS and PVA groups after embolization. The AGS group exhibited a trend of improvement at ~1 week after embolization, and all indicators were statistically different until day 21 compared with the PVA group. The AGS group exhibited improved repair of hepatocytes and the biliary system based on H&E staining, while the PVA group exhibited more severe necrosis of the hepatocytes and biliary system around the embolization site. The western blotting results indicated that the Bcl-2/Bax ratio decreased on day 1 and day 3, and then rebounded in the AGS group on days 7 and 21, demonstrating gradual repair of hepatocytes compared with the PVA group.

The Wavelength-Dependent SERS Template Based on a Nanopillar Array.

Surface-enhanced Raman spectroscopy (SERS) can be regarded as a powerful tool for probing chemical molecules by effectively enhancing Raman signals. However, the enhancement factors depend on the SERS template, the probed molecular structures, and the excitation laser wavelength. Herein, we proposed a simple and easily fabricated nanostructured template for SERS and analyzed the wavelength-dependent factors. Three types of golden nanopillar arrays on silicon wafers were designed and manufactured. The SERS signals of the Rhodamine 6G (R6G) molecules were extracted. Three laser sources, a blue 17 mW 458 nm diode laser, a green 20 mW 532 nm laser, and a red 6 mW 633 nm laser, were employed as the excitation laser sources. The 458 nm laser was located far from the resonate spectrum of R6G. The optical intensity distributions for the different SERS templates excited by three laser beams were also simulated. The enhancement factors (EFs) of R6G on the three nanostructured templates were measured and compared. The photoluminescence spectrum of the nanostructured templates and SERS signals of R6G were also measured. In addition, the experimental results concerned optical simulations. The analysis tool that was used was a convolution profile of multiple Lorentzian line shapes with a Gaussian profile. It is helpful to understand the SERS signals when the excitation laser wavelength is located out of the resonance region of molecules. It can also provide a new design approach to fabricate an SERS Template with a nanopillar array for different excitation wavelengths.

Neoadjuvant treatments for resectable rectal cancer: A network meta-analysis.

Different neoadjuvant therapy regimens are available for rectal cancer, but the relative effects are controversial. The aim of the present network meta-analysis (NMA) was to estimate the relative efficacy and safety of neoadjuvant therapies for resectable rectal cancer. MEDLINE, EMBASE and Cochrane Central Registry of Controlled Trials were searched for publications dated from 1946 up to June 2018. The present study included randomized clinical trials that compared treatments for resected rectal cancer: Surgery alone, surgery preceded by neoadjuvant radiotherapy (RT), neoadjuvant chemotherapy (CT) or neoadjuvant chemoradiotherapy (CRT). Direct pairwise comparisons and NMA were conducted. A total of 23 randomized controlled trials were included in the present study. RT had an overall survival (OS) benefit when compared with surgery alone [HR (hazard ratio), 0.89; 95% confidence interval (CI), 0.82-0.97; quality of evidence, high]. All three neoadjuvant regimens were associated with lower local recurrence (LR) when compared with surgery alone [RT: odds ratio (OR), 0.44; 95% CI, 0.35-0.65; quality of evidence, high; CRT: OR, 0.34; 95% CI, 0.23-0.56; quality of evidence, low and CT: OR, 0.32; 95% CI, 0.11-1.00; quality of evidence, low]. There were no significant differences in OS and LR between CRT and RT (OS: OR, 1.10); 95% CI, 0.93-1.20; LR: OR, 0.81; 95% CI, 0.61-1.10). Ranking probabilities indicated that CRT was the best strategy for local control, with a surface under the cumulative ranking curve (SUCRA) of 78.78%. Patients treated with RT had improved disease-free survival compared with those treated with surgery alone (HR, 0.82; 95% CI, 0.64-1.00; quality of evidence, low). Neoadjuvant RT or CRT did not significantly improve distant metastases compared with surgery alone (RT: OR, 0.87; 95% CI, 0.69-1.10 and CRT: OR, 0.75; 95% CI, 0.47-1.10). CRT had an improved pathological complete response rate compared with RT (OR, 4.90; 95% CI, 21.80-17.00; quality of evidence, low). No significant difference for the risk of anastomotic leak between each treatment was observed in the NMA. In conclusion, RT decreased the LR and improved OS compared with surgery alone for resected rectal cancer. CRT was the best neoadjuvant therapy analyzed and CT was likely the second best for all outcomes based on SUCRA. However, these findings were limited by overall low quality of evidence.

Urinary Trypsin Inhibitor Ameliorates Seawater Immersion-Induced Intestinal Mucosa Injury via Antioxidation, Modulation of NF-κB Activity, and Its Related Cytokines in Rats with Open Abdominal Injury.

Objective. To investigate the role of oxidative stress, NF-κB activity, and its related cytokines in the pathogenesis of seawater immersion after open abdominal injury (SI-OAI) and whether UTI treatment can attenuate SI-OAI induced IMI. Methods. Wistar rats were randomly divided into three groups: C group, S group, and U group. The rats in C group only suffered from anesthesia and surgical operation, whereas the rats in S group and U group received caudal vein injection of normal saline without/with 50,000 U/kg body weight of UTI. The activities of TNF-α, IL-6, SOD, MDA, ROS, NF-κB, and IκB-ß were monitored by ELISA, biochemical methods, EMSA, and Western blot, respectively. Results. The plasma inflammatory mediators and the contents of MDA, ROS, and NF-κB in intestine as well as the pathological scores in ileal mucosa were significantly increased in rats after SI-OAI, accompanied by a reduction in SOD activities and IκB-ß levels. UTI treatment significantly attenuated intestinal histopathological changes with evidence of a decrease in all of the parameters, except for upregulation of the levels of SOD and IκB-ß protein. Conclusion. UTI can attenuate SI-OAI induced IMI via inhibition of NF-κB activity, subsequently inhibiting the expression of inflammatory cytokines and by combating oxidative stress.

Integrated optical gyroscope using active long-range surface plasmon-polariton waveguide resonator.

Optical gyroscopes with high sensitivity are important rotation sensors for inertial navigation systems. Here, we present the concept of integrated resonant optical gyroscope constructed by active long-range surface plasmon-polariton (LRSPP) waveguide resonator. In this gyroscope, LRSPP waveguide doped gain medium is pumped to compensate the propagation loss, which has lower pump noise than that of conventional optical waveguide. Peculiar properties of single-polarization of LRSPP waveguide have been found to significantly reduce the polarization error. The metal layer of LRSPP waveguide is electro-optical multiplexed for suppression of reciprocal noises. It shows a limited sensitivity of ~10(-4) deg/h, and a maximum zero drift which is 4 orders of magnitude lower than that constructed by conventional single-mode waveguide.

A new multichannel spectral imaging laser scanning confocal microscope.

We have developed a new multichannel spectral imaging laser scanning confocal microscope for effective detection of multiple fluorescent labeling in the research of biological tissues. In this paper, the design and key technologies of the system are introduced. Representative results on confocal imaging, 3-dimensional sectioning imaging, and spectral imaging are demonstrated. The results indicated that the system is applicable to multiple fluorescent labeling in biological experiments.

Role of bone marrow-derived mesenchymal stem cells in a rat model of severe acute pancreatitis.

AIM: To investigate the role and potential mechanisms of bone marrow mesenchymal stem cells (MSCs) in severe acute peritonitis (SAP). METHODS: Pancreatic acinar cells from Sprague Dawley rats were randomly divided into three groups: non-sodium deoxycholate (SDOC) group (non-SODC group), SDOC group, and a MSCs intervention group (i.e., a co-culture system of MSCs and pancreatic acinar cells + SDOC). The cell survival rate, the concentration of malonaldehyde (MDA), the density of superoxide dismutase (SOD), serum amylase (AMS) secretion rate and lactate dehydrogenase (LDH) leakage rate were detected at various time points. In a separate study, Sprague Dawley rats were randomly divided into either an SAP group or an SAP + MSCs group. Serum AMS, MDA and SOD, interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α levels, intestinal mucosa injury scores and proliferating cells of small intestinal mucosa were measured at various time points after injecting either MSCs or saline into rats. In both studies, the protective effect of MSCs was evaluated. RESULTS: In vitro, The cell survival rate of pancreatic acinar cells and the density of SOD were significantly reduced, and the concentration of MDA, AMS secretion rate and LDH leakage rate were significantly increased in the SDOC group compared with the MSCs intervention group and the Non-SDOC group at each time point. In vivo, Serum AMS, IL-6, TNF-α and MAD level in the SAP + MSCs group were lower than the SAP group; however serum IL-10 level was higher than the SAP group. Serum SOD level was higher than the SAP group at each time point, whereas a significant between-group difference in SOD level was only noted after 24 h. Intestinal mucosa injury scores was significantly reduced and the proliferating cells of small intestinal mucosa became obvious after injecting MSCs. CONCLUSION: MSCs can effectively relieve injury to pancreatic acinar cells and small intestinal epithelium, promote the proliferation of enteric epithelium and repair of the mucosa, attenuate systemic inflammation in rats with SAP.

Vascular exclusion by preserving tumor-contralateral branch of hepatic artery in hepatectomy in treatment liver cancer with cirrhosis.

BACKGROUND/AIMS: To investigate the effectiveness and safety of vascular exclusion by preserving tumor-contralateral branch of hepatic artery in hepatectomy in treatment liver cancer with cirrhosis. METHODOLOGY: The clinical data of 10 cases treated with hepatectomy for liver cancer were analyzed retrospectively. Vascular exclusion by preserving tumor-contralateral branch of hepatic artery was applied to control bleeding. Blood loss, operative time and postoperative hepatic function were observed. RESULTS: The average blood loss was 515mL, the operative time was 191 minutes and the mean time of exclusion was 30.20 minutes. There is no significant difference between hepatic function (serum total bilirubin, alanine transaminase) of postoperative day 7 and that of pre-operation. CONCLUSIONS: Vascular exclusion by preserving tumor-contralateral branch of hepatic artery could effectively control bleeding and preserve hepatic function and is proved to be applicable to patients of liver cancer with cirrhosis.

Self-assembly of large-scale and ultrathin silver nanoplate films with tunable plasmon resonance properties.

We describe a rapid, simple, room-temperature technique for the production of large-scale metallic thin films with tunable plasmonic properties assembled from size-selected silver nanoplates (SNPs). We outline the properties of a series of ultrathin monolayer metallic films (8-20 nm) self-assembled on glass substrates in which the localized surface plasmon resonance can be tuned over a range from 500 to 800 nm. It is found that the resonance peaks of the films are strongly dependent on the size of the nanoplates and the refractive index of the surrounding dielectric. It is also shown that the bandwidth and the resonance peak of the plasmon resonance spectrum of the metallic films can be engineered by simply controlling aggregation of the SNP. A three-dimensional finite element method was used to investigate the plasmon resonance properties for individual SNPs in different dielectrics and plasmon coupling in SNP aggregates. A 5-17 times enhancement of scattering from these SNP films has been observed experimentally. Our experimental results, together with numerical simulations, indicate that this self-assembly method shows great promise in the production of nanoscale metallic films with enormous electric-field enhancements at visible and near-infrared wavelengths. These may be utilized in biochemical sensing, solar photovoltaic, and optical processing applications.

Tunable microring resonator based on dielectric-loaded surface plasmon polariton waveguides.

Integrated optical ring resonators are essential elemental components for integrated optical circuits. An ultrasmall thermo-optical microring resonator with two bus waveguide-configuration based on surface plasmon polariton waveguide is theoretically analyzed. The thermo-optical coefficient, the temperature-dependent amplitude attenuation coefficient and the temperature distribution properties of the waveguide are investigated numerically by finite element method. The critical resonant conditions of the microring resonator are discussed by considering the propagation losses in the plasmonic ring cavity. The transmission characteristics and the tunability of the ring resonator with different structural parameters are investigated. The results show that the proposed ring resonator with a low driving power and high efficient tunability has potential to develop nano-scope wavelength tunable channel drop filters, low power optical switches, attenuators, and other high compact integrated optical devices.

Numerical analysis of deep sub-wavelength integrated plasmonic devices based on Semiconductor-Insulator-Metal strip waveguides.

We report the first study of nanoscale integrated photonic devices constructed with semiconductor-insulator-metal strip (SIMS) waveguides for use at telecom wavelengths. These waveguides support hybrid plasmonic modes transmitting through a 5-nm thick insulating region with a normalized intensity of 200-300 µm(-2). Their fundamental mode, unique transmission and dispersion properties are consistent with photonic devices for guiding and routing of signals in communication applications. It has been demonstrated using Finite Element Methods (FEM) that the high performance SIMS waveguide can be used to fabricate deep sub-wavelength integrated plasmonic devices such as directional couplers with the ultra short coupling lengths, sharply bent waveguides, and ring resonators having a functional size of ≈1 µm and with low insertion losses and nearly zero radiation losses.