A novel AC flatness adjustment technique for wideband resistive voltage dividers.

Resistive voltage dividers (RVDs) are commonly used as AC attenuation networks in measurement circuits; however, their high-frequency gain is always disturbed by nasty parasitic elements and deviates significantly from the desired design value. This paper proposes a closed-loop adjustment technique for adjusting the frequency response flatness of wideband RVDs (WRVDs). In the proposed adjustment scheme, the frequency response flatness of the WRVD is determined by a voltage-controlled compensation capacitor, whereas the corresponding control voltage is provided by a digital potentiometer. The settling time and the adjustment error of the loop are analyzed to evaluate the adjustment performance. To verify the concept, the adjustment loop is incorporated into a 100:1 WRVD for demonstration. Final experiments show that the proposed technique improves gain flatness by 81 times compared with uncompensated flatness, with 1.15% up to 2 MHz, and that the compensated voltage divider has an excellent linearity of 36 ppm up to 100 V.

Regulation of Li+ Diffusion via an Engineered Separator to Realize a Homogeneous Lithium Microstructure in Advanced Li-Metal Batteries.

Lithium metal, the most promising anode material, is receiving increasing interest owing to its high theoretical capacity (3860 mA h g-1) and low negative potential (-3.04 V vs. standard hydrogen electrode). However, the uneven Li dissolution/deposition behavior causes a degraded cycle stability and safety issues, thus seriously restricting the application of Li-metal batteries (LMBs). Separator modification is one of the most versatile and feasible approaches to overcome this problem. In this study, polypropylene (PP) separators are prepared and coated with an inert hexagonal boron nitride (h-BN) layer, which can provide sufficient ion transport channels and physical protection. The h-BN@PP separator exhibits a remarkable effect on the regulation of the diffusion and nucleation of Li+ to realize a homogeneous Li microstructure, thereby reducing the voltage polarization and improving the cycle performance of the battery. All LMBs equipped with the modified separators exhibit excellent cycling stabilities. The Li|Li symmetric cell exhibits a stable cycling for over 2300 h with a polarization voltage of 13 mV. In conclusion, the modified h-BN@PP separator has significant potential for stabilizing various Li metal anodes, which strongly promotes the applications of advanced LMBs.

Deep Learning-Based Computed Tomography Imaging to Diagnose the Lung Nodule and Treatment Effect of Radiofrequency Ablation.

This study aimed to detect and diagnose the lung nodules as early as possible to effectively treat them, thereby reducing the burden on the medical system and patients. A lung computed tomography (CT) image segmentation algorithm was constructed based on the deep learning convolutional neural network (CNN). The clinical data of 69 patients with lung nodules diagnosed by needle biopsy and pathological comprehensive diagnosis at hospital were collected for specific analysis. The CT image segmentation algorithm was used to distinguish the nature and volume of lung nodules and compared with other computer aided design (CAD) software (Philips ISP). 69 patients with lung nodules were treated by radiofrequency ablation (RFA). The results showed that the diagnostic sensitivity of the CT image segmentation algorithm based on the CNN was obviously higher than that of the Philips ISP for solid nodules <5 mm (63 cases vs. 33 cases) (P < 0.05); it was the same result for the subsolid nodule <5 mm (33 case vs. 5 cases) (P < 0.05) that was slightly higher for solid and subsolid nodules with a diameter of 5-10 mm (37 cases vs. 28 cases) (P < 0.05). In addition, the CNN algorithm can reach all detection for calcified nodules and pleural nodules (7 cases; 5 cases), and the diagnostic sensitivities were much better than those of Philips ISP (2 cases; 3 cases) (P < 0.05). Patients with pulmonary nodules treated by RFA were in good postoperative condition, with a half-year survival rate of 100% and a one-year survival rate of 72.4%. Therefore, it could be concluded that the CT image segmentation algorithm based on the CNN could effectively detect and diagnose the lung nodules early, and the RFA could effectively treat the lung nodules.

FoxO6 inhibits cell proliferation in lung carcinoma through up-regulation of USP7.

Emerging evidence has suggested that misregulation of oncogenes and/or tumor suppressors has a crucial role in the development of lung carcinoma. The present study demonstrated that the expression levels of forkhead box O6 (FOXO6) were downregulated in lung cancer tissue samples, as compared with those in adjacent normal tissue. Overexpression of FOXO6 inhibited the proliferation of A549 human lung cancer cells, whereas knockdown of endogenous FOXO6 expression enhanced cell proliferation. Furthermore, ectopic FOXO6 expression induced the expression of ubiquitin-specific-processing protease 7 (USP7). As a result of this regulation, FOXO6 overexpression led to an elevation of p53 protein expression levels in A549 cells. In conclusion, the results of the present study indicated that the FOXO6/USP7 molecular network has an important role in the regulation of lung cancer development.

Isolation and characterization of a mesophilic Arthrospira maxima strain capable of producing docosahexaenoic acid.

A strain of the cyanobacterium Arthrospira was isolated from Lake Chahannaoer in northern China and was characterized according to microscopic morphology, photosynthetic oxygen-evolving activity, growth rate, and nutritional profile. Compared with thermophilic Arthrospira species occurring naturally in tropical and subtropical lakes, this isolate is mesophilic and grows optimally at ~20 degreesC. The total protein, fatty acid, phycocyanin, carotenoid, and chlorophyll a contents were 67.6, 6.1, 4.32, 0.29, and 0.76 grams per 100 grams of dry weight, respectively. The strain is rich in polyunsaturated fatty acids (PUFAs). An essential omega-3 fatty acid, docosahexaenoic acid (DHA), was detected, and gamma-linolenic acid (GLA) and DHA accounted for 28.3% of the total fatty acid content. These features of this newly isolated strain make it potentially useful in commercial mass culture in local areas or as a biofuel feedstock. It is also an alternative resource for studying the metabolic PUFA pathways and mechanisms of cold stress tolerance in cyanobacteria.

The synthesis of astaxanthin esters, independent of the formation of cysts, highly correlates with the synthesis of fatty acids in Haematococcus pluvialis.

The compositions and contents of astaxanthin esters and fatty acids in four types of Haematococcus pluvialis cells were studied by HPLC and GC-MS. Results showed that the synthesis and accumulation of astaxanthin was independent of the formation of cysts, but was highly correlated with the synthesis and accumulation of fatty acids, though it is an well known phenomenon that the accumulation of astaxanthin is usually accompanied by the formation of cyst. The red cysts contain more than 30% of fatty acids, with 81% of the unsaturated fatty acids. Taken together, besides a resource of astaxanthin, H. pluvialis would be a good resource of valuable fatty acids.

[Laboratory culture of Tetraselmis strains isolated from the coasts of China].

Tetraselmis is an important alga commonly used as live food in aquaculture. This paper reported the laboratory culture of its strains collected from the coasts of China, covering Guangdong, Zhejiang and Shandong Provinces. The separated strains of Tetraselmis for mono-species culture were isolated with capillary method, and their axenic cultures were obtained by inoculating them in plates with solid Marine III medium (M III). Modified Guillard & Ryther medium (MGM), M III, and modified Marine III medium (M III M) were utilized for the liquid cultivation of Tetraselmis in 500 mL flasks. It was displayed that the average growth of Tetraselmis cultured in M III M was the fastest at pH 7.0-8.0, and vitamin B12 addition to M III M slightly increased the relative growth rate of Tetraselmis. Therefore, the modified Marine III medium was effective to use as a large-scale culture medium for Tetraselmis in aquaculture.