All-day uninterrupted thermoelectric generator by simultaneous harvesting of solar heating and radiative cooling.

Passive power generation has recently stimulated interest in thermoelectric generators (TEGs) using the radiative cooling mechanism. However, the limited and unstable temperature difference across the TEGs significantly degrades the output performance. In this study, an ultra-broadband solar absorber with a planar film structure is introduced as the hot side of the TEG to increase the temperature difference by utilizing solar heating. This device not only enhances the generation of electrical power but also realizes all-day uninterrupted electrical output due to the stable temperature difference between the cold and hot sides of the TEG. Outdoor experiments show the self-powered TEG obtains maximum temperature differences of 12.67 °C, 1.06 °C, and 5.08 °C during sunny daytime, clear nighttime, and cloudy daytime, respectively, and generates output voltages of 166.2 mV, 14.7 mV, and 95 mV, respectively. Simultaneously, the corresponding output powers of 879.25 mW/m2, 3.85 mW/m2, and 287.27 mW/m2 are produced, achieving 24-hour uninterrupted passive power generation. These findings propose a novel strategy to combine solar heating and outer space cooling by a selective absorber/emitter to generate all-day continuous electricity for unsupervised small devices.

Fingerprint detection in the mid-infrared region based on guided-mode resonance and phonon-polariton coupling of analyte.

Mid-infrared absorption spectroscopy is an effective method for detecting analyte fingerprints without labeling, but the inherent loss of metals in current methods is a main issue. Here, a sensing scheme was proposed that uses an all-dielectric grating metasurface and angular scanning of polarized light, and then it was verified by numerical simulation. The proposed fingerprint detection scheme could effectively couple a guided-mode resonance spectrum peak with the characteristic peak of the analyte's phonon-polariton in the mid-infrared region, significantly enhancing the interaction between light and the analyte. The novel scheme would realize broadband enhancement to detect a variety of substances, and facilitate mid-infrared sensing and analysis of trace substances.

Numerical analysis of an ultra-wideband metamaterial absorber with high absorptivity from visible light to near-infrared.

In this study, we designed a novel ultra-wideband (UWB) absorber and numerically analyzed it to demonstrate that its light absorptivity was greater than 90% in the wavelength range of visible light and near-infrared (405-1505 nm). The structure of proposed novel UWB absorber consisted of four layers of films, including silica, titanium, magnesium fluoride, and aluminium, and the upper silica and titanium layers had rectangular cubes in them. For that, the excitations of propagating surface plasmon resonance (PSPR), local surface plasmon resonance (LSPR), and the resonance of Fabry-Perot (FP) cavity were generated at the same time and combined to reach the effect of perfect absorption and ultra-wideband. The proposed absorber had an average absorptivity of 95.14% in the wavelength range of 405 ∼ 1505 nm when the light was under normal incidence. In addition, the UWB absorber was large incident angle insensitive and polarization-independent. The absorber proposed in the paper had great prospects in the fields of thermal electronic equipment, solar power generation, and perfect cloaking.

Magnetically controlled capsule endoscopy as the first-line examination for high-risk patients for the standard gastroscopy: a preliminary study.

Background: Magnetically controlled capsule endoscopy (MCE) has emerged as a feasible and efficient diagnostic modality for gastric diseases. In a special group of patients, MCE may have an advantage over standard gastroscopy. Objective: This study aimed to evaluate the clinical utility of MCE in high-risk patients for standard gastroscopy. Methods: In this study, patients with high-risk factors for standard gastroscopy were examined by MCE between 1 January 2017 and 31 December 2017. The examination time, results, adverse events and clinical outcome were recorded. Results: Forty-two patients with high-risk factors for standard gastroscopy were enrolled in the present study. All patients successfully underwent MCE without any adverse events. Based on the findings from MCE, the patients were successfully treated. Conclusions: For patients with high-risk factors for standard gastroscopy, MCE could be the perfect alternative examination for gastric diseases. We recommend MCE as the first-line examination for high-risk patients, but its utility should be confirmed in further clinical studies.

Factors associated with endoscopic full-thickness resection of gastric submucosal tumors.

OBJECTIVE: To identify factors that impact the procedure and treatment outcomes for endoscopic full-thickness resection (EFTR) of gastric submucosal tumors (SMTs). METHODS: Medical records were collected for all patients with gastric SMTs who underwent EFTR procedures in Shengjing Hospital between June 2012 and April 2014. The data from each patient were reviewed, including gender, age, maximum tumor size on endoscopic ultrasound (EUS), tumor location in stomach, length of EFTR procedure, pneumoperitoneum during EFTR, cost to close defects, length of hospital stay after the procedure, and procedure-related complications. RESULTS: Endoscopic full-thickness resection of gastric SMTs was successfully performed in all 41 patients. Maximum size on EUS [parameter estimate (PE) = 4.443, 95% confidence interval (CI) 2.191-6.695; p = 0.000] and tumor location in the greater curvature (PE = 44.441, 95% CI 5.539-83.343; p = 0.026) were significantly associated with the length of the procedure. A pneumoperitoneum was more likely to occur during EFTR in tumors with a larger EUS size [odds ratio (OR) = 1.415, 95% CI 1.034-1.936; p = 0.03], and less likely to occur during EFTR for tumors located in the posterior wall (OR = 0.003, 95% CI 0-0.351; p = 0.017). The use of the over-the-scope clip (OTSC) system was significantly associated with shorter hospital stays (PE = -1.006, 95% CI -1.998 to -0.014; p = 0.047) and a higher cost of closing defects (PE = 854.742, 95% CI 358.377-1351.107; p = 0.001). CONCLUSIONS: Endoscopic full-thickness resection is an effective and safe method for removing gastric SMTs. Tumor size on EUS and location of the tumor were associated with the duration of EFTR and the occurrence of a pneumoperitoneum during the procedure. The use of an OTSC system was significantly associated with shorter hospital stays and a higher cost of closing defects.

EUS assisted transmural cholecystogastrostomy fistula creation as a bridge for endoscopic internal gallbladder therapy using a novel fully covered metal stent.

BACKGROUND: Laparoscopic cholecystectomy (LC) has become the "gold standard" for treating symptomatic gallstones. Innovative methods, such as a scarless therapeutic procedure through a natural orifice are being introduced, and include transgastric or transcolonic endoscopic cholecystectomy. However, before clinical implementation, instruments still need modification, and a more convenient treatment is still needed. The aim of this study was to evaluate the feasibility of endoscopic internal gallbladder therapy such as cholecystolithotomy in an animal survival model. METHODS: Four pigs underwent endoscopic-ultrasound (EUS)-guided cholecystogastrostomy and the placement of a novel covered mental stent. Four weeks later the stents were removed and an endoscope was advanced into the gallbladder via the fistula, and cholecystolithotomy was performed. Two weeks later the pigs were sacrificed, and the healing of the fistulas was assessed. RESULTS: EUS-guided cholecystogastrostomy with mental stent deployment was successfully performed in all the animals. Four weeks after the procedure, the fistulas had formed and all the stents were removed. Endoscopic cholecystolithotomy was performed through each fistula. All the animals survived until they were sacrificed 2 weeks later. The fistulas were found to be completely healed. CONCLUSIONS: This study reports the first endoscopic transmural cholecystolithotomy after placement of a novel mental stent in an animal survival model.

Methods to increase the diagnostic efficiency of endoscopic ultrasound-guided fine-needle aspiration for solid pancreatic lesions: An updated review.

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a means to procure adequate specimens for histological and cytologic analysis. The ideal EUS-FNA should be safe, accurate, and have a high sample adequacy rate and low adverse events rate. In recent years, many guidelines and trials on EUS-FNA have been published. The purpose of this article is to provide an update on the influence of some of the main factors on the diagnostic efficiency of EUS-FNA as well as a rare but serious complication known as needle tract seeding.

Standardized construction of a porcine model for acute obstructive jaundice and training of endoscopic ultrasound-guided choledochoduodenostomy.

Background: Endoscopic ultrasound-guided biliary drainage (EUS-BD) is an alternative to endoscopic retrograde cholangiopancreatography (ERCP) for patients with obstructive jaundice. However, it is still a challenge for many endoscopists because of its novelty and complexity. This study aimed to establish an ideal bile duct dilatation model for the training and practice of endoscopic ultrasound-guided choledochoduodenostomy (EUS-CDS). Methods: The 34 healthy Bama miniature pigs were divided into the part of developing the standardized EUS-CDS (n=9) and the part of trainees training (n=25). Part one, two different methods were used to clip Vater's ampulla using metal clips to establish an extrahepatic bile duct dilatation model. Part two, five trainees were trained on EUS-CDS with 25 pigs. Following a 2-week observation period, the feasibility and effectiveness of the technique were evaluated. Results: In the group with three metal clips perpendicular to the duodenal wall clipping Vater's ampulla, the success rate of extrahepatic bile duct dilation greater than 1 cm in 24 h was 5/6, whereas the remaining one pig was 48 h. All five trainees can finally complete the EUS-CDS independently. No death occurred during the 2-week observation period. Conclusion: Clipping Vater's ampulla with three metal clips perpendicular to the duodenal wall is an effective and stable method to create a porcine bile duct dilatation model.

Broadband Solar Metamaterial Absorbers Empowered by Transformer-Based Deep Learning.

The research of metamaterial shows great potential in the field of solar energy harvesting. In the past decade, the design of broadband solar metamaterial absorber (SMA) has attracted a surge of interest. The conventional design typically requires brute-force optimizations with a huge sampling space of structure parameters. Very recently, deep learning (DL) has provided a promising way in metamaterial design, but its application on SMA development is barely reported due to the complicated features of broadband spectrum. Here, this work develops the DL model based on metamaterial spectrum transformer (MST) for the powerful design of high-performance SMAs. The MST divides the optical spectrum of metamaterial into N patches, which overcomes the severe problem of overfitting in traditional DL and boosts the learning capability significantly. A flexible design tool based on free customer definition is developed to facilitate the real-time on-demand design of metamaterials with various optical functions. The scheme is applied to the design and fabrication of SMAs with graded-refractive-index nanostructures. They demonstrate the high average absorptance of 94% in a broad solar spectrum and exhibit exceptional advantages over many state-of-the-art counterparts. The outdoor testing implies the high-efficiency energy collection of about 1061 kW h m-2 from solar radiation annually. This work paves a way for the rapid smart design of SMA, and will also provide a real-time developing tool for many other metamaterials and metadevices.

Progress in Endoscopic Treatment of Hemorrhoids.

Hemorrhoids are one of the most common diseases of the anorectal region. Previously, treatment for hemorrhoids included conservative treatment, outpatient treatment, and surgical treatment. The development of flexible reversible endoscopes has provided precise controllability and imaging, enabling further improvement and development of various endoscopic techniques to treat hemorrhoids. This article discusses several of these endoscopic techniques: rubber band ligation, sclerotherapy, and electrocoagulation. The development, efficacy, and advantages of these treatments are summarized and evaluated. It is expected that going forward, endoscopic technology will be further applied in clinical practice and may become the first-line method for the treatment of hemorrhoids.