Misalignment and Range Adaptive Wireless Charging System with Constant Current/Constant Voltage Output Based on Coupling Coefficient Estimation

Compared with the traditional plug-in charging system, wireless power transfer (WPT) system has the characteristics of electrical and mechanical isolation. A wireless system is proposed suitable for battery charging under misalignment or range variation, and the constant current (CC) and constant voltage (CV) charging are realized by the estimation of coupling coefficient. Firstly, two different operating frequencies based on SS basic compensation structure are designed to realize CC output and CV output respectively. After circuit analysis, CC and CV output cannot be achieved when the position of the secondary coil changes. To solve this issue, when the coil is under misalignment or range variations, the required system parameters are measured, and the coupling coefficient in the charging process is estimated by using the transconductance amplitude equation. Then the corresponding input voltage or working frequency is calculated and fine-tuned. Therefore, the CC and CV charge of the battery can be realized under misalignment or range variation. Finally, experimental results are presented to verify the feasibility and correctness of this method.

In vitro development of mechanically and enzymatically isolated cat ovarian follicles

Graphical Abstract Isolation of ovarian follicles is a key step in culture systems for large mammalian species to promote the continued growth of follicles beyond the preantral stage in fertility preservation efforts. Still, mechanical isolation methods are user-skill dependent and time-consuming, whereas enzymatic strategies carry increased risk of damaging theca cell layers and the basement membranes. Here, we sought to determine an optimal method to rescue domestic cat (Felis catus) early antral and antral stage follicles from ovarian tissue and to evaluate the influence of isolation strategy on follicle development, survival, and gene expression during 14 days of in vitro culture in alginate hydrogel. Mechanical isolation was compared with 90 min digestion in 0.7 and 1.4 Wünsch units/mL Liberase blendzyme (0.7L and 1.4L, respectively). Mechanical isolation resulted in improved follicle growth and survival, and better antral cavity and theca cell maintenance in vitro, compared with 1.4L (P < 0.05) but displayed higher levels of apoptosis after incubation compared with enzymatically isolated follicles. However, differences in follicle growth and survival were not apparent until 7+ days in vitro. Expressions of CYP19A1, GDF9, LHR, or VEGFA were similar among isolation-strategies. Cultured follicles from all isolation methods displayed reduced STAR expression compared with freshly isolated follicles obtained mechanically or via 0.7L, suggesting that prolonged culture resulted in loss of theca cell presence and/or function. In sum, early antral and antral stage follicle development in vitro is significantly influenced by isolation strategy but not necessarily observable in the absence of extended culture. These results indicate that additional care must be taken in follicle isolation optimizations for genome rescue and fertility preservation efforts. Lay summary The ovary contains hundreds of eggs with only a select few developing from an immature stage through to ovulation over the course of an animal's lifetime. Rescue of eggs from this pool, and the ability to grow them in culture to a mature stage, would be incredibly valuable for fertility preservation efforts in both humans and endangered species. Currently, the isolation of ovarian follicles (eggs with their surrounding helper cells) is a key step in culture systems for large mammalian species, to promote continued growth. Yet, isolation methods may affect the follicle’s future developmental capacity. We evaluated two isolation strategies, mechanical micro-dissection (needle/scalpel blade) and enzymatic digestion (using Liberase blendzyme) on ovaries of domestic cats obtained via routine spay procedures. Mechanically isolated follicles displayed improved growth, survival, and indications of developmental competence in 14-day culture, compared with high concentration (1.4 Wünsch units/mL) enzyme-isolated follicles. However, mechanical isolation was not different from low (0.7 Wünsch units/mL) enzyme for these metrics, or for expression of key genes indicative of follicular cell functions. Further, differences in follicle growth/survival were not apparent until 7+ days in culture. Thus, ovarian follicle isolation strategies influence developmental potential in culture, and extended culture will be required to identify optimal methods for fertility preservation efforts.

A Solution for Mechanical Isolation Volume Refracturing in Ultra-Low Permeability Horizontal Wells: A Case Study in Ordos Basin

With the rise of volume fracturing concept and its application in new wells, it has been shown that increasing fracturing volume is an effective measure to improve production and achieve long-term stable production of ultra-low permeability reservoirs in Ordos Basin. However, refracturing requires running liner, which makes the flow passage smaller and can't reach the volume of new wells. The challenge is how to design the tubing combination and develop matching tools to further improve refracturing volume in 5.5″ casing. The objectives of this study are to design a combined mechanical isolation liner and carry out fine-staged large-volume refracturing with a rate of 8 m3/min in 5.5″ casing. In this study, researchers have designed the liner, optimized refracturing tools and wellhead equipment by comprehensively considering reservoir pressure, wellbore, available tubing combinations and friction of fracturing fluid. Downhole microseismic technology is used to monitor refracturing microseismic events, and high-precision 3D scanning technology is used to detect and analyze the wall wear of liners after refracturing. Field tests have been carried out in Ordos ultra-low permeability horizontal wells and achieved perfect effect. This research provides a reliable solution and technical reserve for volume refracturing of ultra-low permeability reservoir in horizontal wells, and verifies that large-volume plays an important role in improving refracturing effect in the test area.

Phenotypic and Cellular Characteristics of a Stromal Vascular Fraction/Extracellular Matrix Gel Prepared Using Mechanical Shear Force on Human Fat

The retention of fat-derived grafts remains a challenge for regenerative medicine. Fat aspirates from patients undergoing liposuction were prepared into standard Coleman fat grafts or further isolated using mechanical shear force to prepare a stromal vascular fraction (SVF)/extracellular matrix (ECM) gel. The retention rate of the SVF/ECM gel was significantly higher than that of the Coleman fat at 3, 14, 28, and 60 days following transplantation on the backs of nude mice. The viscosity of the fat was directly proportional to the shearing force. Although the mechanical isolation did not affect the total number of cells, it significantly decreased the number of living cells. Flow cytometry showed a greater number of mesenchymal stem cells, supra-adventitial (SA)-adipose stromal cells (ASCs), and adipose-derived stem cells but a lower number of endothelial progenitor cells in the SVF/ECM gel than in the Coleman fat. Thus, mechanical isolation of fat can increase the pluripotency of adipocytes, which can improve graft retention in cell therapy.

Nonlinear Dynamics of Marine Rotor System Coupled with Air Bag-Floating Raft Subjected to the Basement Excitations in Lateral Directions

This paper presents an investigation into the nonlinear dynamic behaviors of the mechanical isolation system coupled with air-bag and floating-raft subject to basement excitation in lateral directions. First, the coupling effects between the excitation source and isolation system are considered. Also, the mechanical isolation model under basic excitation and its motion equation are deduced, and then the dynamic responses are mainly investigated by using the techniques of displacement response, frequency spectrum, rotor orbit, Poincaré maps, and the bifurcation diagram. Last, the bifurcations of the mechanical isolation system with different parameters are analyzed through numerical methods, especially the effect of excitation frequency and amplitude. The result predicts that period-5 is mainly performed, with the increase of rotor speed, and the system moves into quasi-bifurcation. However, the system stays in chaos state at high rotor speed, and the vibration amplitude rises rapidly until against bearing bush. Furthermore, the effects of basement excitation on the mechanical isolation system are mainly concentrated on the stage of lower rotor speed, but with the increasing speed, the effects become weak and at the same time the vibration amplitude reduces significantly. The points projected on the Poincaré section are five, three, or two solitary attractors, in which the system stays in periodic motion. Above all, the dynamic characteristics can provide the theoretic supporting for the dynamic, vibration control and its parametric optimization of the marine mechanical isolation system coupled with air-bag and floating-raft.

Developing and validating protocols for mechanical isolation of guard-cell enriched epidermal peels for omics studies

Stomata, which are microscopic valves on the leaf surface formed by two guard cells (GC), play a critical role in the regulation of leaf water and gas exchange and, hence, determine plant adaptive potential. However, little data is available on GC biochemistry, protein abundance and gene expression, mainly due to technical difficulties and challenges in isolating sufficient amounts of high-quality pure GC. In the present study we applied some modifications to the mechanical isolation of guard-cell to generalise this method for diverse growth conditions as well as plant species. Epidermal peel fragments enriched in guard cells were mechanically isolated from quinoa, spinach and sugar beet leaves grown at two conditions (normal and salt stress). Multiple analysis was performed to confirm the suitability and superiority of the modified technique to the original method. At the first step, the viability and purity of GC-enriched epidermal fragments were assessed under the microscope. Then, the RNA integrity, gene expression, and 1D SDS-PAGE tests were performed to validate the suitability of this technique for omics studies. The data revealed a wide range of proteins as well as a high integrity of RNA extracted from guard cell samples. The expression level of several GC-specific genes and mesophyll-dominant genes were investigated using a comparative analysis of transcriptome datasets of GC and whole-leaf samples. We found that Rubisco and photosynthesis-related proteins such as chlorophyll a/b binding protein were substantially higher in the whole leaf compared with the GCs. More importantly, GC-specific genes such as OST1, SLAC1, MYB60, FAMA and HT1 were highly expressed in the GCs, confirming that our guard cell preparation was highly enriched in GC gene transcripts. Real-time quantitative reverse transcription PCR further confirmed the efficacy of the GC isolation technique for exploring responses of GC to diverse types of stress at the molecular level.

Establishment of a protocol for the isolation of ovarian preantral follicles derived from collared peccaries (Pecari tajacu)

SummaryWe compare the efficiency of mechanical or enzymatic methods, and their combination, for the isolation of ovarian preantral follicles (PFs) from collared peccaries. The ovaries from six females were subjected to the different methods investigated here. For the enzymatic method, ovary fragments were exposed to collagenase type IV in TCM-HEPES medium; the mechanical procedure was based on ovarian cortex dissociation by using a scalpel blade. The residual solution obtained after the mechanical isolation was subjected to the enzymatic procedure. The number of isolated PFs was quantified and classified as primordial, primary, or secondary; their viability was assessed using trypan blue dye assay. To confirm the results, PFs derived from the most efficient method were evaluated for integrity using scanning electron microscopy (SEM) and subjected to a 24 h in vitro culture for subsequent evaluation of viability by using fluorescent probes. A higher number of PFs (P &lt; 0.05) was obtained from the enzymatic method (961.7 ± 132.9) in comparison with the mechanical method (434.3 ± 88.9), but no difference was observed between the two methods and their combination (743.2 ± 92.8). The trypan blue assay showed that the enzymatic method (98.7 ± 0.6%) provided the highest percentage of viable follicles (P &lt; 0.05). Furthermore, SEM confirmed the ultrastructural integrity of the surface architecture of peccary PFs isolated by the enzymatic procedure; epifluorescence microscopy was used to confirm their viability (86.0%). In conclusion, we suggest that the enzymatic method investigated here is useful for the isolation of viable ovarian PFs from collared peccaries.

Fractionation of Adipose Tissue Procedure With a Disposable One-Hole Fractionator

Background Adipose tissue has been widely used in regenerative surgery for its therapeutic potential. This potential is often ascribed to the stromal vascular fraction (SVF), which can be mechanically isolated. Mechanical isolation results in an SVF that retains intact cell-cell communication including extracellular matrix and is therefore named tissue-SVF (tSVF). Objectives The aim of this study was to evaluate a new disposable 1-hole fractionator for fractionation of adipose tissue (FAT), and compare this new device with the existing reusable 3-hole fractionator. Methods The composition of tSVF obtained via the 1-hole fractionator was histologically and histochemically compared to unprocessed adipose tissue. The number of viable nuclear cells in tSVF obtained by the 1-hole and 3-hole fractionators as well as unprocessed adipose tissue were compared after enzymatic isolation and tested for colony-forming capacity. Flow cytometry was used to compare different cell compositions based on surface marker expression between tSVF isolated by the two types of fractionators. Results Fractionation of adipose tissue with the 1-hole fractionator condenses vasculature and extracellular matrix by disrupting adipocytes. The number of viable nuclear cells in tSVF obtained with the two fractionators was comparable and significantly higher than unprocessed lipoaspirate. Furthermore, tSVF isolated by both fractionators showed similar cell compositions and comparable colony-forming capacities. Conclusions FAT with a disposable 1-hole fractionator effectively isolates tSVF with a cell count and cell composition comparable to the fraction obtained with the 3-hole reusable fractionator. The disposable 1-hole fractionator, however, is safer and more user friendly.