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Optofluidic tunable microlens arrays (MLAs) can manipulate and control light propagation using fluids. Lately, their applicability to miniature lab-on-a-chip systems is being extensively researched. However, it is difficult to incorporate 3D MLAs directly in a narrow microfluidic channel using common techniques. This has resulted in limited research on variable focal length imaging with optofluidic 3D MLAs. In this paper, we propose a method for fabricating MLAs in polydimethylsiloxane (PDMS)-based microchannels via electrohydrodynamic jet (E-jet) printing to achieve optofluidic tunable MLAs. Using this method, MLAs of diameters 15 to 80 μm can be fabricated in microfluidic channels with widths of 200 and 300 μm. By alternately using solutions with different refractive indices in the microchannel, the optofluidic microlenses exhibit reversible modulation properties while retaining the morphologies and refractive indices of the microlenses. The focal length of the resulting optofluidic chip can have threefold tunability, thereby achieving an imaging depth of approximately 450 μm. This outstanding advantage is useful in observing microspheres and cells flowing in the microfluidic system. Thus, the proposed optofluidic chip exhibits great potential for cell counting and imaging applications.

Background: Tibial Cortex Transverse Transport (TTT) represents an innovative surgical method for treating lower extremity diabetic foot ulcers (DFUs), yet its underlying mechanisms remain elusive. Establishing an animal model that closely mirrors clinical scenarios is both critical and novel for elucidating the mechanisms of TTT. Methods: We established a diabetic rat model with induced hindlimb ischemia to mimic the clinical manifestation of DFUs. TTT was applied using an external fixator for regulated bone movement. Treatment efficacy was evaluated through wound healing assessments, histological analyses, and immunohistochemical techniques to elucidate biological processes. Results: The TTT group demonstrated expedited wound healing, improved skin tissue regeneration, and diminished inflammation relative to controls. Marked neovascularization and upregulation of angiogenic factors were observed, with the HIF-1α/SDF-1/CXCR4 pathway and an increase in EPCs being pivotal in these processes. A transition toward anti-inflammatory M2 macrophages indicated TTT's immunomodulatory capacity. Conclusion: Our innovative rat model effectively demonstrates the therapeutic potential of TTT in treating DFUs. We identified TTT's roles in promoting angiogenesis and modulating the immune system. This paves the way for further in-depth research and potential clinical applications to improve DFU management strategies.

Tunable microlens arrays (MLAs) with controllable focal lengths have been extensively used in optical sensors, biochips, and electronic devices. The commonly used method is electrowetting on dielectric (EWOD) that controls the contact angle of the microlens to adjust the focal length. However, the fabrication of tunable MLAs at the microscale remains a challenge because the size of MLAs is limited by the external electrodes of EWOD. In this study, a highly integrated planar annular microelectrode array was proposed to achieve an electrowetting tunable MLA. The planar microelectrode was fabricated by electrohydrodynamic jet (E-jet) printing and the liquid microlens was then deposited in situon the microelectrode. This method could realize 36 tunable liquid microlenses with an average diameter of 24 μm in a 320 × 320 μm2plane. The fabricated tunable MLAs with higher integration levels and smaller sizes can be beneficial for cell imaging, optofluidic systems, and microfluidic chips.

In vitrobiofabrication is employed in fields such as biomedicine and those using biomimetic materials. However, it suffers from drawbacks such as low resolution, applicability on a limited range of components, and difficulty in purposefully depositing specific cells in three-dimensional space. Hence, this paper proposes a digital micromirror device-based optical projection lithography (DOPL) system for producing multi-component microstructures with resolutions of tens of microns and explores the behavior of cells with these structures. The printability and mechanical properties of these microstructures were investigated to assess their reproduction quality and the ability to control their structural characteristics. The results show that when DOPL is used with polyethylene glycol dimethacrylate (PEGDMA) hydrogel, an array of micropits can be fabricated within a few minutes. Furthermore, uniform cell spheroids form rapidly with high throughput when they are seeded into the micropits. Additionally, PEGDMA and gelatin methacryloyl (GelMA) were used to construct multi-component microstructures, and it was demonstrated that cells with various morphologies selectively adhere to the heterogeneous interface. In addition, DOPL could enable deposition of various cells for constructing microenvironments and for drug screening. Finally, a biomimetic peritoneal model was constructed. Overall, this work demonstrates the versatility of this system and its potential in cellular applications such as cell behavior research, drug screening, and tissue engineering.

Fuel cells produce electricity via an electrochemical procedure by which energy contained in fuel is immediately transformed into DC electricity. Various other features, functions and benefits of fuel cells are highlighted, and their future role in producing electricity aboard ships is emphasized.

ABSTRACTWith increasing interests in using LNG as a marine fuel, safety issues for LNG bunkering have brought about global discussion on establishing a safety exclusion zone around LNG bunkering areas. However, international consensus has yet to be reached in determining an appropriate extent of the zone to ensure safe liquefied natural gas (LNG) bunkering. The purpose of this study is to identify potential risks of LNG bunkering and to present a statistical method for determining the safe exclusion zone around LNG bunkering station with the help of a purpose-built computer program, integrated quantitative risk assessment (IQRA). A probabilistic risk assessment approach was adopted in this study to determine the safety exclusion zone for two case ships: one, a 300,000 DWT very large ore carrier (VLOC) and the other a 32,000 DWT bulk carrier. The results are then compared with those obtained by a deterministic approach and the discrepancies are discussed. It was found from this study that the frequency of bunkering is one of the key factors in determining the extent of safety exclusion zone. Thus, a somewhat surprising result of 36 m radius safety exclusion zone for the 32,000 DWT bulk carrier compared to 6.4 m radius for the 300,000 DWT VLOC was obtained. It was also found that the deterministic approach produced a much more extensive safety exclusion zone for the 300,000 DWT VLOC subjected to infrequent large-scale LNG bunkering operations compared to the probabilistic approach, while it was reasonably consistent with the probabilistic approach for the 32,000 DWT bulk carrier which uses frequent small-scale bunkering.

In this article, we present a novel method of spatial manipulation and assembly of nanoparticles via atomic force microscopy tip-induced dielectrophoresis (AFM-DEP). This method combines the high-accuracy positioning of AFM with the parallel manipulation of DEP. A spatially nonuniform electric field is induced by applying an alternating current (AC) voltage between the conductive AFM probe and an indium tin oxide glass substrate. The AFM probe acted as a movable DEP tweezer for nanomanipulation and assembly of nanoparticles. The mechanism of AFM-DEP was analyzed by numerical simulation. The effects of solution depth, gap distance, AC voltage, solution concentration, and duration time were experimentally studied and optimized. Arrays of 200 nm polystyrene nanoparticles were assembled into various nanostructures, including lines, ellipsoids, and arrays of dots. The sizes and shapes of the assembled structures were controllable. It was thus demonstrated that AFM-DEP is a flexible and powerful tool for nanomanipulation.

Selective catalytic reduction (SCR) is a promising technique for reducing nitrogen oxide (NOx) emissions from diesel engines. Static mixers are widely used in SCR systems before reactors to promote the mixing of ammonia and exhaust streams. This work aims to investigate the effects of the location of static mixers and the volume ratio of two species on mixing quality using the computational fluid dynamics (CFD) method. The simulation results show that a more homogenous ammonia distribution can be achieved at the exit of the pipe if static mixers are placed close to the ammonia injection point or if more ammonia is injected. Another phenomenon found in the study is that the mixing performance of an identical static mixer may behave discrepantly under different flow conditions if using Band Cas the evaluating indexes for mixing homogenization.

Two types of nylon-1010/MMT nanocomposites were successfully prepared by melt intercalation using a corotating twin-screw extruder. The nanocomposites were characterized with X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). It was found that the difference in the properties of the two types of the organo-MMTs directly influences the structure and the properties of the obtained nanocomposites. The results of XRD and TEM showed that the DK2-MMT nanocomposites possess an exfoliated structure and the nanocomposites containing 16C-MMT exist as intercalated structures. The mechanical properties of the nylon-1010/organo-MMTs nanocomposites were better than those of the pure nynon-1010. In addition, the properties of the DK2-MMT nanocomposites were superior to those of the 16C-MMT nanocomposites because of the different dispersibility of the two organo-MMTs. The thermal stability of the nanocomposites was improved. The storage moduli of the nanocomposites increased and the glass-transition temperature shifted to a slightly higher temperature because of the introduction of the organo-MMTs. The addition of DK2-MMT into the nylon-1010 matrix accelerated the crystallization rate of the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:1834-1841, 2004

Bioinspired by natural superhydrophobic surface with hierarchical micro–nanostructures, waterproof artificial compound eyes with variable field of view (FOV) were fabricated by a simple and effective manufacturing method.The fabricated artificial compound eyes exhibited excellent waterproof property, tunability of the FOV and optical performance.