Design, Fabrication, and Characterization of a Bifrequency Colinear Array

Ultrasound imaging with high resolution and large penetration depth has been increasingly adopted in medical diagnosis, surgery guidance, and treatment assessment. Conventional ultrasound works at a particular frequency, with a −6 dB fractional bandwidth of ~70 %, limiting the imaging resolution or depth of field. In this paper, a bi-frequency co-linear array with resonant frequencies of 8 MHz and 20 MHz was investigated to meet the requirements of resolution and penetration depth for a broad range of ultrasound imaging applications. Specifically, a 32-element bi-frequency co-linear array was designed and fabricated, followed by element characterization and real-time sectorial scan (S-scan) phantom imaging using a Verasonics system. The bi-frequency co-linear array was tested in four different modes by switching between low and high frequencies on transmit and receive. The four modes included the following: (1) transmit low, receive low, (2) transmit low, receive high, (3) transmit high, receive low, (4) transmit high, receive high. After testing, the axial and lateral resolutions of all modes were calculated and compared. The results of this study suggest that bi-frequency co-linear arrays are potential aids for wideband fundamental imaging and harmonic/sub-harmonic imaging

Ferroptosis-associated circular RNAs: Opportunities and challenges in the diagnosis and treatment of cancer

Ferroptosis is an emerging form of non-apoptotic regulated cell death which is different from cell death mechanisms such as autophagy, apoptosis and necrosis. It is characterized by iron-dependent lipid peroxide accumulation. Circular RNA (circRNA) is a newly studied evolutionarily conserved type of non-coding RNA with a covalent closed-loop structure. It exhibits universality, conservatism, stability and particularity. At present, the functions that have been studied and found include microRNA sponge, protein scaffold, transcription regulation, translation and production of peptides, etc. CircRNA can be used as a biomarker of tumors and is a hotspot in RNA biology research. Studies have shown that ferroptosis can participate in tumor regulation through the circRNA molecular pathway and then affect cancer progression, which may become a direction of cancer diagnosis and treatment in the future. This paper reviews the molecular biological mechanism of ferroptosis and the role of circular RNA in tumors and summarizes the circRNA related to ferroptosis in tumors, which may inspire research prospects for the precise prevention and treatment of cancer in the future

Performance assessment of medical service for organ transplant department based on diagnosis-related groups: A programme incorporating ischemia-free liver transplantation in China

BackgroundIn July 2017, the first affiliated hospital of Sun Yat-sen university carried out the world’s first case of ischemia-free liver transplantation (IFLT). This study aimed to evaluate the performance of medical services pre- and post-IFLT implementation in the organ transplant department of this hospital based on diagnosis-related groups, so as to provide a data basis for the clinical practice of the organ transplant specialty.MethodsThe first pages of medical records of inpatients in the organ transplant department from 2016 to 2019 were collected. The China version Diagnosis-related groups (DRGs) were used as a risk adjustment tool to compare the income structure, service availability, service efficiency and service safety of the organ transplant department between the pre- and post-IFLT implementation periods.ResultsIncome structure of the organ transplant department was more optimized in the post-IFLT period compared with that in the pre-IFLT period. Medical service performance parameters of the organ transplant department in the post-IFLT period were better than those in the pre-IFLT period. Specifically, case mix index values were 2.65 and 2.89 in the pre- and post-IFLT periods, respectively (p = 0.173). Proportions of organ transplantation cases were 14.16 and 18.27%, respectively (p < 0.001). Compared with that in the pre-IFLT period, the average postoperative hospital stay of liver transplants decreased by 11.40% (30.17 vs. 26.73 days, p = 0.006), and the average postoperative hospital stay of renal transplants decreased by 7.61% (25.23 vs.23.31 days, p = 0.092). Cost efficiency index decreased significantly compared with that in the pre-IFLT period (p < 0.001), while time efficiency index fluctuated around 0.83 in the pre- and post-IFLT periods (p = 0.725). Moreover, the average postoperative hospital stay of IFLT cases was significantly shorter than that of conventional liver transplant cases (p = 0.001).ConclusionThe application of IFLT technology could contribute to improving the medical service performance of the organ transplant department. Meanwhile, the DRGs tool may help transplant departments to coordinate the future delivery planning of medical service

Effect of Human Immunodeficiency Virus Infection on Human Papillomavirus Clearance among Women in Senegal, West Africa

Thesis (Master's)--University of Washington, 2021Background. Persistent infection with human papillomavirus (HPV) is associated with development of cervical-related disease. Methods. A total of 174 Senegalese women completed health questionnaires and were tested for Human Immunodeficiency Virus (HIV) upon enrollment, as well as were tested HPV at baseline and during follow up. The 2-year cumulative incidence of clearance of type-specific HPV infection was estimated by Kaplan-Meier methods. Marginal Cox proportional hazards models stratified by incident/prevalent HPV infection were used to evaluate the effect of HIV status and type on HPV clearance. Results. Incident HPV infections in HIV-positive women were 34% less likely to be cleared than those in HIV-negative women (adjusted HR=0.66, 95% CI: 0.44-0.99), but the association was not significant for prevalent HPV infections (adjusted HR=1.16, 95% CI: 0.81-1.67). For HIV-positive women, we observed no significant association between HIV type and clearance of HPV infection among incident HPV infections (HIV-2 vs HIV-1: adjusted HR=1.61, 95% CI: 0.93-2.80; Dually infected vs HIV-1: HR=1.50, 95% CI: 0.87-2.57) and among prevalent HPV infections (HIV-2 vs HIV-1: adjusted HR=0.77, 95% CI: 0.23-2.66; Dually infected vs HIV-1: HR=0.71, 95% CI: 0.36-1.38). Incident HPV infections in women with CD4 cell counts ≤500 were 37% less likely to be cleared than those in women with CD4 cell counts >500 (adjusted HR=0.63, 95% CI: 0.41-0.97), but the association was not significant for prevalent HPV infections (adjusted HR=0.87, 95% CI: 0.46-1.63). Conclusions. HIV infection reduces the likelihood of clearance of incident HPV infection. CD4 cell count is considered as a more effective predictor of HPV clearance than HIV type

Research on corrosion mechanism of overhead conductor

During the operation of overhead conductors, conductors are corroded to varying degrees by the smoke and dust, harmful gases from factories around the lines, or in corrosive salt fog atmosphere in coastal and island areas, as well as humid and hot weather conditions. In this paper, through the study of the corrosion mechanism of the conductor, the types of the corrosion are analyzed, and the factors leading to the corrosion and the corrosion process are analyzed by selecting the steel cored aluminum stranded wire, so as to provide theoretical basis for the development of anti-corrosion wire and the judgment of corrosion detection

An Integrated Front-end Circuit Board for Air-Coupled CMUT Burst-Echo Imaging

To conduct burst-echo imaging with air-coupled capacitive micromachined ultrasonic transducers (CMUTs) using the same elements in transmission and reception, this work proposes a dedicated and integrated front-end circuit board design to build an imaging system. To the best of the authors’ knowledge, this is the first air-coupled CMUT burst-echo imaging using the same elements in transmission and reception. The reported front-end circuit board, controlled by field programmable gate array (FPGA), consisted of four parts: an on-board pulser, a bias-tee, a T/R switch and an amplifier. Working with our 217 kHz 16-element air-coupled CMUT array under 100 V DC bias, the front-end circuit board and imaging system could achieve 22.94 dB signal-to-noise ratio (SNR) in burst-echo imaging in air, which could represent the surface morphology and the three-dimensional form factor of the target. In addition, the burst-echo imaging range of our air-coupled CMUT imaging system, which could work between 52 and 273 mm, was discussed. This work suggests good potential for ultrasound imaging and gesture recognition applications

Changes of Physicochemical Properties in Black Garlic during Fermentation

To investigate the changes of the main ingredients in black garlic (BG) during fermentation, the contents of moisture, total acids and reducing sugars were determined. Allicin, 5-Hydroxymethylfurfural (5-HMF), and total phenols were also determined as bioactive substances. DPPH scavenging capacity was determined to indicate the antioxidant activity of BG. The changes in hardness and color were detected as well. The results showed that the moisture content decreased from 66.13% to 25.8% during the fermentation. The content of total acids, total phenols, and reducing sugars increased from 0.03 g/g to 0.29 g/g, from 0.045 μg/g to 0.117 μg/g, and from 0.016 g/g to 0.406 g/g, respectively. The content of 5-HMF increased from 0 to 4.12 μg/mL continuously, while the content of allicin increased from 0.09 mmol/100 g to 0.30 mmol/100 g and then decayed to 0.00 mmol/100 g. The L*, a*, and b* values of BG were 23.65 ± 0.44, 0.64 ± 0.06, and 0.85 ± 0.05, respectively. There was a higher intensity of dark color in BG than that in fresh garlic. The hardness values decreased first and then increased in later fermentation from 465.47 g to 27,292.38 g. Principal component analysis (PCA) showed that the samples were divided into three clusters, including cluster1 (fresh garlic, S0), cluster2 (S1), and cluster3 (S3−S9). This research effectively clarified the various stage of the BG fermentation process, and it is expected to supply references for reducing production time in industrial BG fermentation

Changes of Physicochemical Properties in Black Garlic during Fermentation

To investigate the changes of the main ingredients in black garlic (BG) during fermentation, the contents of moisture, total acids and reducing sugars were determined. Allicin, 5-Hydroxymethylfurfural (5-HMF), and total phenols were also determined as bioactive substances. DPPH scavenging capacity was determined to indicate the antioxidant activity of BG. The changes in hardness and color were detected as well. The results showed that the moisture content decreased from 66.13% to 25.8% during the fermentation. The content of total acids, total phenols, and reducing sugars increased from 0.03 g/g to 0.29 g/g, from 0.045 μg/g to 0.117 μg/g, and from 0.016 g/g to 0.406 g/g, respectively. The content of 5-HMF increased from 0 to 4.12 μg/mL continuously, while the content of allicin increased from 0.09 mmol/100 g to 0.30 mmol/100 g and then decayed to 0.00 mmol/100 g. The L*, a*, and b* values of BG were 23.65 ± 0.44, 0.64 ± 0.06, and 0.85 ± 0.05, respectively. There was a higher intensity of dark color in BG than that in fresh garlic. The hardness values decreased first and then increased in later fermentation from 465.47 g to 27,292.38 g. Principal component analysis (PCA) showed that the samples were divided into three clusters, including cluster1 (fresh garlic, S0), cluster2 (S1), and cluster3 (S3−S9). This research effectively clarified the various stage of the BG fermentation process, and it is expected to supply references for reducing production time in industrial BG fermentation

Exploring Core Microbiota Based on Characteristic Flavor Compounds in Different Fermentation Phases of Sufu

Sufu, a Chinese traditional fermented soybean product, has a characteristic foul smell but a pleasant taste. We determined the core functional microbiota and their metabolic mechanisms during sufu fermentation by examining relationships among bacteria, characteristic flavor compounds, and physicochemical factors. Flavor compounds in sufu were detected through headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry, and the microbial community structure was determined through high-throughput 16S rRNA sequencing. The results showed that the fermentation process of sufu could be divided into early and late stages. The early stage was critical for flavor development. Seven microbiota were screened based on their abundance, microbial relevance, and flavor production capacity. Five microbes were screened in the early stage: Pseudomonas, Tetragenococcus, Lysinibacillus, Pantoea, and Burkholderia–Caballeronia–Paraburkholderia. Three microbes were screened in the late stage: Exiguobacterium, Bacillus, and Pseudomonas. Their metabolic profiles were predicted. The results provided a reference for the selection of enriched bacterial genera in the fermentation process and controlling applicable process conditions to improve the flavor of sufu

A Transmission Price Design Considering the Marginal Benefits of the Transmission and Spatiotemporal Information of Electricity Demand

One of the most critical tasks of China’s power sector reformation is re-designing transmission and distribution (T&D) prices, which are essential in establishing fair and ordered power markets and encouraging the efficient allocation of resources. In view of the problems in China’s power market, such as the lack of a market mechanism for the reasonable allocation of congestion revenue, unreasonable transmission cost composition, and the failure of the transmission pricing mechanism to reflect the utilization degree of transmission resources by users in different geographical locations, this study proposes a transmission price design under the application scenarios of regional power grids and provincial power grids dominated by meshed AC networks in China that considers the marginal benefit of the transmission and spatiotemporal information of electricity demand. The proposed method effectively tackles the above-mentioned problem, with the transmission cost being divided into two parts: the expansion cost reflecting the marginal benefits of transmission, and the residual cost reflecting the rest. The expansion cost is objective and based on power system economics; it is calculated as the congestion revenue under the location marginal price-based wholesale electricity markets, resulting in a more reasonable division of transmission costs and allocation of congestion revenue. Furthermore, allocating the residual cost with the power flow distribution factor and the postage stamp method also reflects the utilization degree of transmission resources by users in different geographical locations. The effectiveness of this transmission price design is confirmed by testing it against a 3-bus and an IEEE 30-bus system