Search Results (4)

A novel design method based on a novel origami process that can create a solid structure swiftly and at a low cost is presented for rectangular waveguide-type microwave devices in this paper. A planar structure was fabricated by the lamination and laser cutting of polystyrene membranes and aluminum foils and was converted into a solid structure via origami in accordance with the selective absorption of infrared light. A rectangular waveguide, a rectangular waveguide-type coupler, and a power divider based on an origami structure with a multi-layer structure and a single-layer structure were fabricated and tested, demonstrating easy assembly and good microwave performance. The measured results of the rectangular waveguide indicated that the insertion loss was superior to −0.9 dB. Meanwhile, the results of the coupler showed that the coupling degree increased from −12.8 dB to −8.9 dB in the range of 11.0 GHz to 12.0 GHz. Correspondingly, the prepared power divider demonstrated that the return loss dwindled from −8.9 dB to −11.3 dB and that the insertion loss of one output port was approximate to that of the remaining one, varying between −3.5 dB and −5.2 dB in the range of 10.5 GHz to 11.5 GHz—verifying the effectiveness of the origami-based design method. Full article

Studies show that the systematic study of the stiffness characteristics of the laminated membrane coupling is helpful to analyze the vibration status of the shaft system deeply and accurately. Moreover, such an investigation can provide a reliable guarantee for the safe operation of the power plant. Therefore, establishing an accurate expression for the stiffness and analyzing its characteristics have great significance. In the present study, a finite element model of the waist type laminated membrane coupling is established which considers the influence of the contact between laminations. In order to evaluate the performance of the proposed method, four stiffness characteristics of the coupling are analyzed, including torsional, axial, radial and angular stiffness. The torsional stiffness is verified by the static torsional test. The influence of the flange elasticity and the friction coefficient between the laminations on the stiffness characteristics of the coupling is studied. In the present study, variations of the flange stiffness, the pre-tightening force of the bolt and the friction coefficient between the laminations are studied based on the results obtained from the finite element method. It is expected that the present study can provide a reference for designing and application of the lamination coupling. Full article

Male infertility is observed in approximately 50% of all couples with infertility. Intracytoplasmic sperm injection (ICSI), a conventional artificial reproductive technique for treating male infertility, may fail because of a severe low sperm count, immotile sperm, immature sperm, and sperm with structural defects and DNA damage. Our previous studies have revealed that mutations in the septin (SEPT)-coding gene SEPT12 cause teratozoospermia and severe oligozoospermia. These spermatozoa exhibit morphological defects in the head and tail, premature chromosomal condensation, and nuclear damage. Sperm from Sept12 knockout mice also cause the developmental arrest of preimplantation embryos generated through in vitro fertilization and ICSI. Furthermore, we found that SEPT12 interacts with SPAG4, a spermatid nuclear membrane protein that is also named SUN4. Loss of the Spag4 allele in mice also disrupts the integration nuclear envelope and reveals sperm head defects. However, whether SEPT12 affects SPAG4 during mammalian spermiogenesis remains unclear. We thus conducted this study to explore this question. First, we found that SPAG4 and SEPT12 exhibited similar localizations in the postacrosomal region of elongating spermatids and at the neck of mature sperm through isolated murine male germ cells. Second, SEPT12 expression altered the nuclear membrane localization of SPAG4, as observed through confocal microscopy, in a human testicular cancer cell line. Third, SEPT12 expression also altered the localizations of nuclear membrane proteins: LAMINA/C in the cells. This effect was specifically due to the expression of SEPT12 and not that of SEPT1, SEPT6, SEPT7, or SEPT11. Based on these results, we suggest that SEPT12 is among the moderators of SPAG4/LAMIN complexes and is involved in the morphological formation of sperm during mammalian spermiogenesis. Full article

Miniature ultrasonic lysis for biological sample preparation is a promising technique for efficient and rapid extraction of nucleic acids and proteins from a wide variety of biological sources. Acoustic methods achieve rapid, unbiased, and efficacious disruption of cellular membranes while avoiding the use of harsh chemicals and enzymes, which interfere with detection assays. In this work, a miniature acoustic nucleic acid extraction system is presented. Using a miniature bulk acoustic wave (BAW) transducer array based on 36° Y-cut lithium niobate, acoustic waves were coupled into disposable laminate-based microfluidic cartridges. To verify the lysing effectiveness, the amount of liberated ATP and the cell viability were measured and compared to untreated samples. The relationship between input power, energy dose, flow-rate, and lysing efficiency were determined. DNA was purified on-chip using three approaches implemented in the cartridges: a silica-based sol-gel silica-bead filled microchannel, nucleic acid binding magnetic beads, and Nafion-coated electrodes. Using E. coli, the lysing dose defined as ATP released per joule was 2.2× greater, releasing 6.1× more ATP for the miniature BAW array compared to a bench-top acoustic lysis system. An electric field-based nucleic acid purification approach using Nafion films yielded an extraction efficiency of 69.2% in 10 min for 50 µL samples. Full article