Large Droplets Research Articles

Modeling on the size of the pre-breaking molten droplet in plasma atomization for controlling the size of the produced powders

In two-phase flow atomization, e.g., Electrode Induction Gas Atomization (EIGA) and Plasma Atomization (PA), the size of the produced powder is greatly affected by the size of the large droplet fed into the atomization zone, which is named the pre-breaking molten droplet (PbMD). In EIGA, the size of the PbMD can be quantitatively modeled as its generation from a rod by induction melting is relatively simple. While in PA, the generation of PbMD from a metal wire involves complex heat and mass transfer behavior, and there currently lacks of any quantitative model on the size of the PbMD in PA, resulting in unpredictable production of metal powders. Therefore, modeling on the size of the PbMD in PA was carried out in this study. Firstly, new phenomenological models were established to show the change in the state of the molten metal during the generation of PbMD in PA. Based on the phenomenological models, a theoretical equation for calculating the size of the PbMD with two unknown error variables was successfully deduced. Observation experiments were conducted using a high-speed camera to obtain the size of the PbMD in PA, which was used to determine the unknown error variables and verify the proposed calculation equation. The verification experiments showed that the error between the calculated and experimental results was within 10%. Moreover, it was found that the size of the PbMD in PA was much smaller than that in EIGA, which makes PA easier to produce fine powders. It was also observed that the average size of the PbMD and its variance increased with the increasing arc current of the plasma generator while decreasing with the increasing gas flow rate. With the proposed model, the size of the PbMD in PA can be predicted, and the size of the produced powders can be controlled.

275-LB: Mitochondrial Fission Factor Can Be a Key Factor in the Regulation of Hepatic Lipid Metabolism

Nonalcoholic fatty liver disease (NAFLD) develops into nonalcoholic steatohepatitis (NASH) when fat accumulates in the liver, leading to hepatocyte apoptosis, inflammation and fibrosis. No effective treatments for NASH have been established. Mitochondria are important organelles that play a central role in de novo lipogenesis and fatty acid β-oxidation. We have shown that mitochondrial fission is enhanced by short-term high-fat diet (HFD) loading, but is impaired by long-term. We speculated that mitochondrial fission inhibition is associated with the development of NASH and generated mice deletion of hepatocyte-specific mitochondrial fission factor (KO) mice. Conditioning HFD, KO mice showed inhibition of hepatocyte mitochondrial fission, increased ER stress and decreased triglyceride secretion from the liver. The hepatic triglyceride contents had significantly increased in KO mice compared to control (CONT), and histological analysis showed a marked increase in large lipid droplets (LDs). In addition to marked fat accumulation, hepatic apoptosis, inflammation and fibrosis were increased in the livers of KO mice, indicating the development of NASH. We noted that large LDs were increased in KO mice and added an additional analysis to determine how mitochondrial fission inhibition is involved in LDs formation in the liver. Oleic acid is a representative monounsaturated fatty acid that promotes LDs deposition in hepatocytes and is mildly cytotoxic by inducing ER stress and apoptosis. Loading primary cultured hepatocytes (PH) with oleic acid increased the number of smaller LDs in PH of CONT mice, whereas LDs in cells of KO mice became larger. Gene expression of Cidec, which acts on the fusion of LDs, was increased in the liver of KO mice, suggesting that inhibition of mitochondrial fission may induce the fusion of LDs and the enlargement of intracellular LDs in the liver. Further analysis is planned, as inhibition of mitochondrial fission may be involved in changes of LDs morphology. Disclosure Y. Takeichi: None. T. Miyazawa: None. Y. Ogawa: None.

Coalescence behavior and mechanism of autopoietic droplets on slippery liquid-infused porous surfaces (SLIPS)

Droplets coalescence is an important stage in the self-repair process of the SLIPS. To reveal the coalescence behavior and mechanism, a numerical model for the coalescence of microdroplets on SLIPS was established. The morphological changes and flow characteristics during droplets coalescence were analyzed. The result shows that a concave liquid bridge is formed when the spreading leading edges of the two droplets meet. And the pressure in the liquid bridge is negative. During the coalescence process, the absolute value of the negative pressure gradually decreased. After two droplets merge into a large droplet, the pressure in the large droplets is positive and far less than that in the droplets before coalescence. In the process of coalescence, a velocity gradient will appear on the liquid–gas interface, resulting in vortex rings in the liquid bridge. The vorticity of the main vortex ring is continuously released to produce many small vortex rings, which causes the liquid–gas interface to fluctuate until the vorticity is completely dissipated. With the increase of the inherent contact angle of the wall, the vorticity of the vortex ring near the liquid bridge is larger, and the height of the bridge increases rapidly. The existence of the vortex ring can promote droplet coalescence.

Production of small powder-stabilized droplets using superhydrophobic mesh

Massive production of tiny droplets is critical for industrial processes and biomedical applications. Such droplets are formed by splitting the bulk liquid (top-down) or condensation to grow the droplet (bottom-up). Various generation methods have been reported; however, the generated droplets stick to the contacting substrate and/or coalesce into a larger droplet, limiting handling flexibility and/or size uniformity. Herein, tiny powder-stabilized droplets were massively generated by applying pulse pressure to a “powdered” superhydrophobic mesh on a water pool. The generated droplets were stabilized by a fine hydrophobic powder, namely, liquid marble, which does not coalesce or stick to the contact materials. The effects of mesh size, wettability, powdering, and applied pressure on the droplet formation dynamics were investigated. The generated droplet size depended on the mesh size and droplets were not formed on the hydrophilic mesh. When the superhydrophobic mesh gradually sank into the water pool to apply quasi-static hydro-pressure, the penetrated water did not split, and a continuous large water droplet was formed. However, tapping the superhydrophobic mesh to apply pulsed hydro-pressure induced multiple droplets to split through the mesh penetration. Without powder, the formed droplets coalesced to form large droplets. However, when the superhydrophobic mesh was powdered, the formed droplets were coated with the hydrophobic powder to form a liquid marble, preventing their coalescence.

Human abdominal subcutaneous-derived active beige adipocytes carrying FTO rs1421085 obesity-risk alleles exert lower thermogenic capacity.

Introduction: White adipocytes store lipids, have a large lipid droplet and few mitochondria. Brown and beige adipocytes, which produce heat, are characterized by high expression of uncoupling protein (UCP) 1, multilocular lipid droplets, and large amounts of mitochondria. The rs1421085 T-to-C single-nucleotide polymorphism (SNP) of the human FTO gene interrupts a conserved motif for ARID5B repressor, resulting in adipocyte type shift from beige to white. Methods: We obtained abdominal subcutaneous adipose tissue from donors carrying FTO rs1421085 TT (risk-free) or CC (obesity-risk) genotypes, isolated and differentiated their preadipocytes into beige adipocytes (driven by the PPARγ agonist rosiglitazone for 14 days), and activated them with dibutyryl-cAMP for 4 hours. Then, either the same culture conditions were applied for additional 14 days (active beige adipocytes) or it was replaced by a white differentiation medium (inactive beige adipocytes). White adipocytes were differentiated by their medium for 28 days. Results and Discussion: RNA-sequencing was performed to investigate the gene expression pattern of adipocytes carrying different FTO alleles and found that active beige adipocytes had higher brown adipocyte content and browning capacity compared to white or inactive beige ones when the cells were obtained from risk-free TT but not from obesity-risk CC genotype carriers. Active beige adipocytes carrying FTO CC had lower thermogenic gene (e.g., UCP1, PM20D1, CIDEA) expression and thermogenesis measured by proton leak respiration as compared to TT carriers. In addition, active beige adipocytes with CC alleles exerted lower expression of ASC-1 neutral amino acid transporter (encoded by SLC7A10) and less consumption of Ala, Ser, Cys, and Gly as compared to risk-free carriers. We did not observe any influence of the FTO rs1421085 SNP on white and inactive beige adipocytes highlighting its exclusive and critical effect when adipocytes were activated for thermogenesis.

Study on arc duration and erosion characteristics of cable electrodes in AC series circuits

Arc duration and erosion characteristics of cables are closely related to electrical fire hazards. In this study, the arc duration and arc erosion characteristics of copper and aluminum core cables were explored. The main erosion modes of copper core cable with mica insulation (HC0) and aluminum core cable with polyimide (PI) insulation (HA0) were determined. Results show that several large molten droplets with diameters of 5 ± 0.5 mm would drip down from the molten pool on the cable end during arcing of HC0, but the molten droplets are adhered to the molten pool and do not drip down during arcing of HA0. We concluded that the differences in melting energy and oxide film between copper and aluminum are the main reasons for this phenomenon. Besides, the molten pool can be formed on the cable end as the insulation is heatproof, which plays a vital role in prolonging the arc duration of cables. The arc duration of cables with heatproof insulation is longer than those with common insulation. This means that the cables with heatproof insulation have higher fire hazards from the perspective of arc duration. To further understand the influence of molten pools on arc duration, an arc duration model was developed based on energy balance, which is beneficial in determining the arc duration of cables with heatproof insulation in electrical fire accident investigation.

Numerical analysis on extinguishing of sprinklers in a hydrogen pool fire

Due to the strengthened air pollution regulations, research on hydrogen commercialization is being actively conducted. However, there is a lack of research on the use of hydrogen on ships and the fires. The fire dynamics simulator (FDS, ver. 6.7.8) was used to evaluate optimal sprinkler parameters when the fire broke out after the liquid hydrogen leaked from hydrogen storage tank on the ship's deck using hydrogen fuel cell and formed a pool. It was simulated that simulations were performed to evaluate suitable parameters, droplet size and spray velocity, for extinguishing the hydrogen pool fire and to apprehend the optimal number of sprinklers with suitable parameters. The results indicate that the fire could not be completely extinguished when a low spray velocity of 10 m/s and a large droplet size of 300 μm were set, but the temperature of the fire source could be effectively suppressed when suitable parameters (30 m/s, 30 μm) were selected. However, because one sprinkler with selected conditions was not able to completely extinguish the hydrogen pool fire, it was derived that three or more sprinkler have to be installed. Based on these results, this study presented the minimum extinguishing conditions in the marine system, which is a limited environment.

Size distribution measurement of mixed abrasive slurry for chemical mechanical planarization using an electrospray scanning mobility particle sizer

As the popularity of mixed abrasive slurry (MAS) use in chemical mechanical planarization (CMP) increases, analysis of number concentration and mixing ratios become increasingly important. In this study, the applicability of an electrospray-scanning mobility particle sizer (ES-SMPS) to particle-size analysis of MAS for measuring number concentration and mixing ratio is investigated. Additives to improve the CMP process cause non-volatile residue (NVR) peaks, making it difficult to obtain clear particle-size distributions. Because NVR peaks are affected by the size of the generated droplets, an aerosol generator that produces droplets of different sizes. Compared to atomizers that generate large droplets, an electrospray that generates small droplets minimizes disturbance of NVR peaks, allowing for clear particle-size distributions. Using ES-SMPS, the number concentration and mixing ratio of an MAS were analyzed with no interference from NVR peaks. CMP evaluation of an MAS of a certain number concentration confirmed that using an MAS with a constant number concentration improves the removal rate. Number concentration–based MAS analysis is therefore possible using existing weight concentration–based MAS research and ES-SMPS measurements. Measurement of abrasive number concentrations using ES-SMPS can also provide more realistic information on the number of participating abrasives.

Effects of Oscillation Width on Arc Characteristics and Droplet Transfer in Vertical Oscillation Arc Narrow-Gap P-GMAW of X80 Steel

In fields, such as oil and gas pipelines and nuclear power, narrow-gap welding has often been used for the connection of thick and medium-thick plates. During the welding process, a lack of fusion was prone to occur due to groove size limitations, seriously affecting the service safety of large structures. The vertical oscillation arc pulsed gas metal arc welding (P-GMAW) method was adopted for narrow-gap welding in this study. The influence of the oscillation width on arc morphology, droplet transfer behavior and weld formation during narrow-gap welding was studied. Oscillation widths from 0 to 4 mm were used to weld narrow-gap grooves with a bottom width of 6 mm. The results show that, in non-oscillation arc welding, the arc always presented a bell cover shape, and the droplet transfer was in the form of one droplet per pulse, while the sidewall penetration of the weld was relatively small, making it prone to a lack of fusion. With an increase in the oscillation width, the arc gradually shifted to the sidewall. The droplet transfer mode was a mixed transfer of large and small droplets, and the sidewall penetration continued to increase, which was conducive to the fusion of the sidewall. However, when the oscillation width was wider than 3 mm, it led to the phenomenon of the arc climbing to the sidewall, and the weld was prone to porosity, undercutting and other welding defects. The oscillation width has a major impact on the stability of the welding process in vertical oscillation arc narrow-gap welding.

Adipocyte-Targeting Type I AIE Photosensitizer for Obesity Treatment via Photodynamic Lipid Peroxidation.

Obesity is a surging public health risk and is often associated with fatal diseases, including diabetes, stroke, and myocardial infarction. Common methods for obesity treatment include diet control, weight-loss medicine, and bariatric surgery, but these methods are often ineffective or unsafe. Herein, we introduce a minimally invasive and effective approach to reduce excessive fat accumulation by utilizing red/near-infrared emissive and lipid droplet targeting aggregation-induced emissive luminogens (AIEgens), namely, TTMN and MeTTMN, for specific targeting and photoinduced peroxidation of large lipid droplets in adipocytes. The reported AIEgens can trace and monitor the formation process of adipocytes from pre-adipocytes with a high signal-to-noise ratio. In addition, the presented AIEgens act as Type I photosensitizer that generates highly reactive hydroxyl radicals and superoxides under white light to eliminate mature adipocytes through the chain reactions of lipid peroxidation, even under low oxygen supply. We also demonstrate the use of AIEgens for in vivo photodynamic therapy (PDT) for subcutaneous fat reduction treatment. This work demonstrates the use of AIEgen as a dual imaging and Type I photosensitizer for photodynamic therapeutics to induce adipocyte apoptosis, involving a simple fabrication and treatment process. The suggested in vivo photodynamic obesity treatment processes have negligible toxicity toward nontargeted normal tissues, providing an alternative approach for effective and relatively safer obesity treatment in the future.

Water repellency by volcanic ash interacting with organic matter: Incubation response and effect on infiltration

Volcanic ash deposition disrupts soil surface hydrology. Our previous study showed that soil infiltration was reduced eightfold after a volcanic eruption in various land-use systems adjacent to Mount Kelud (Indonesia). Yet, soil macroporosity was relatively unchanged, indicating soil hydrophobicity. We tested the hypothesis that hydrophobicity or water repellency (WR) can be induced by volcanic ash interacting with organic matter and quantified its effect on surface water infiltration.We combined volcanic ash with leaf litter from coffee, durian, pine and mixed sources and tested for WR as a function of incubation time (0–16 weeks) and soil water content (θ, %), with Water Drop Penetration Time (WDPT, s) and Contact Angle (CA, o) as WR metrics. Lipids content (%) and pH were also analysed during incubation. Water droplets were placed onto a material tested for WR in a slope-adjustable stage to determine the critical angle for droplet runoff before penetration. Finally, to quantify the effect of WR on water flow, we layered 5 and 10 cm of ash with organic matter additions on top of a control soil column and performed infiltration (hydraulic conductivity) measurements.Among litter sources, pine litter induced the highest WR. There were significant relationships between WR, lipid, and pH. However, these relationships became weaker with material water contents > 7%. A significant relationship was also found between CA and critical slope of both small and large drops. A higher CA lowered the minimum critical slope for droplet runoff to 7° and 10° for the diameters of large and small water droplets, respectively. The mixture of volcanic ash and organic matter layered into the soil surface resulted in a five-times lower average hydraulic conductivity, with indications of air entrapment limiting water infiltration in a thicker ash layer. A higher CA was strongly associated with a lower hydraulic conductivity ratio, particularly under the 5 cm organic matter treatment. The WR effects on hydraulic conductivity are equivalent to at least a ten-fold reduction in effective soil porosity. By reducing infiltration, WR may contribute to ash movement in the volcanic landscape.

Limitations of Atomistic Molecular Dynamics to Reveal Ejection of Proteins from Charged Nanodroplets.

Atomistic molecular dynamics (MD) is frequently used to unravel the mechanisms of macroion release from electrosprayed droplets. However, atomistic MD is currently feasible for only the smallest window of droplet sizes appearing at the end steps of a droplet's lifetime. The relevance of the observations made to the actual droplet evolution, which is much longer than the simulated sizes, has not been addressed yet in the literature. Here, we perform a systematic study of the desolvation mechanisms of poly(ethylene glycol) (PEG), protonated peptides of different compositions, and proteins, to (a) obtain insight into the charging mechanism of macromolecules in larger droplets than those that are currently amenable to atomistic MD and (b) examine whether currently used atomistic MD modeling can establish the extrusion mechanism of proteins from droplets. To mimic larger droplets that are not amenable to MD modeling, we scale down the systems, by simulating a large droplet size relative to the macromolecule. MD of PEG charging reveals that, above a critical droplet size, ions are available near the backbone of the macromolecule, but charging occurs only transiently by transfer of ions from the solvent to the macroion, while below the critical size, the capture of the ion from PEG has a lifetime sufficiently long for the extrusion of a charged PEG from the aqueous droplet. This is the first report of the role of droplet curvature in the relation between macroion conformation and charging. Simulations of protonated peptides with a high degree of hydrophobicity show that partial extrusion of a peptide from the droplet surface is rare relative to desolvation by drying-out. Different from what has been presented in the literature, we argue that atomistic MD simulations have not sufficiently established the extrusion mechanism of proteins from droplets and their charging mechanism. We also argue that release of highly charged proteins can occur at an earlier stage of a droplet's lifetime than predicted by atomistic MD. In this earlier stage, we emphasize the key role of jets emanating from a droplet at the point of charge-induced instability in the release of proteins.

Observational Investigation of the Effect of Turbulence on Microphysics and Precipitation in Warm Marine Boundary Layer Clouds

AbstractTurbulence is omnipresent in the marine boundary layer (MBL) and several mechanisms have been proposed regarding its role on MBL cloud microphysics. In particular, past modeling studies suggested that increasing turbulence broaden the droplet size distribution (DSD) and leads to precipitation initiation, this suggested relationship has not been evaluated yet using long‐term observations. Here, comprehensive retrievals from long‐term ground‐based observations are used to explore the impact of turbulence on microphysics and precipitation in drizzling MBL clouds. Our analysis supports that broader DSD and larger droplets are observed with strong turbulence, but interestingly, the precipitation is reduced instead of being enhanced. This suppression mechanism is mainly due to the entrainment and mixing process in which the entrained dry air evaporates cloud water. This study provides observational evidence to show the complex effect of turbulence on MBL cloud properties and implies the potential influence of turbulence on the clouds lifetime.

Dynamics of Droplet Coalescence on Hydrophobic Fibers in Oil: Morphology and Liquid Bridge Evolution.

Although droplet self-jumping on hydrophobic fibers is a well-known phenomenon, the influence of viscous bulk fluids on this process is still not fully understood. In this work, two water droplets' coalescence on a single stainless-steel fiber in oil was investigated experimentally. Results showed that lowering the bulk fluid viscosity and increasing the oil-water interfacial tension promoted droplet deformation, reducing the coalescence time of each stage. While the total coalescence time was more influenced by the viscosity and under-oil contact angle than the bulk fluid density. For water droplets coalescing on hydrophobic fibers in oils, the expansion of the liquid bridge can be affected by the bulk fluid, but the expansion dynamics exhibited similar behavior. The drops begin their coalescence in an inertially limited viscous regime and transition to an inertia regime. Larger droplets did accelerate the expansion of the liquid bridge but had no obvious influence on the number of coalescence stages and coalescence time. This study can provide a more profound understanding of the mechanisms underlying the behavior of water droplet coalescence on hydrophobic surfaces in oil.

The synergism of improving interfacial properties between betaine and crude oil for enhanced oil recovery

Betaine, an emerging surfactant for enhanced oil recovery (EOR), has garnered increased attention and recognition. This study focuses on linear alkylbenzene sulfonate betaine (ASB) as the research subject, and different crude oils were utilized to prepare two types of oil–water formulations with high interfacial film strengths but differed interfacial tensions. The interfacial properties were characterized and explored using interfacial dilational rheology, droplet squeeze coalescence, interfacial tension, emulsification, microscopic visualization, and other measuring methods. The actual emphasis in interfacial film properties of betaine as a standalone chemical EOR formulation was clarified. The results indicated that betaine had generally high interfacial film strength with selected crude oils, at this time, the slight difference in film strength had a negligible effect on enhancing the recovery. The main contributing factor was the difference in interfacial tension between the oil and water. Ultra-low interfacial tension could increase the stripping efficiency of oil in pore, reduce the energy required to emulsification or oil droplets initiation, and ensure that droplets were displaced and collected in smaller sizes, thereby avoiding large oil droplets trapped in the pore throat and unable to pass. Making good use of the advantages of improving sweep efficiency brought by high interfacial film strength, at the same time giving the system ultra-low oil–water interfacial tension, ensuring the start-up and migration of porous crude oil, is the core construction principle of betaine surfactant applied to EOR.

PLA/modified-starch blends and their application for the fabrication of non-woven fabrics by melt-blowing

Blends of polylactic acid (PLA) and thermoplastic starch (TS) with and without chemical modification were obtained by melt extrusion and used to obtain non-woven fabrics by melt-blowing for the first time. Different TS were obtained by reactive extrusion from native cassava, oxidized, maleated, and dual modified (oxidized and maleated) starch. The chemical modification of starch decreases the difference in viscosity and favors blending, resulting in more homogeneous morphologies, unlike the blends with unmodified TS, which displayed a visible phase separation with large TS droplets. The dual modified starch showed a synergistic effect to process TS by melt-blowing. Regarding non-woven fabrics, values in diameter (2.5–82.1 μm), thickness (0.4–0.6 mm), and grammage (49.9–103.8 g/m2) were explained due to differences in viscosity of the components, and to the fact that during melt the hot air preferentially stretches and thins the areas without large droplets of TS. Moreover, plasticized starch acts as a flow modifier. The porosity of the fibers increased with the addition of TS. Further studies and optimization of blends with low contents of TS and type starch modification will be necessary to completely understand these systems with very complex behavior to obtain non-woven fabrics with improved properties and application.

Initialization of Nanowire or Cluster Growth Critically Controlled by the Effective V/III Ratio at the Early Nucleation Stage.

For self-catalyzed nanowires (NWs), reports on how the catalytic droplet initiates successful NW growth are still lacking, making it difficult to control the yield and often accompanying a high density of clusters. Here, we have performed a systematic study on this issue, which reveals that the effective V/III ratio at the initial growth stage is a critical factor that governs the NW growth yield. To initiate NW growth, the ratio should be high enough to allow the nucleation to extend to the entire contact area between the droplet and substrate, which can elevate the droplet off of the substrate, but it should not be too high in order to keep the droplet. This study also reveals that the cluster growth between NWs is also initiated from large droplets. This study provides a new angle from the growth condition to explain the cluster formation mechanism, which can guide high-yield NW growth.

Effects of Aerosol Number Concentration and Updraft Velocity on Relative Dispersion during the Collision–Coalescence Growth Stage of Warm Clouds

Relative dispersion (ɛ) is a key expression used to parameterize various cloud processes in global circulation models (GCMs) and meteorological mesoscale models. Aerosols, updraft velocity (w), and different growth stages of warm clouds are known to affect relative dispersion. A two-dimensional detailed bin microphysical cloud model is used to investigate the combined impacts of aerosol number concentration (Na) and updraft velocity on relative dispersion in the collision–coalescence stage. In addition, the causes potentially controlling the changes in ɛ with updraft velocity are explored. There are three main influence regimes: the updraft velocity main influence regime, the aerosol main influence regime, and the joint influence regime. The cause of the variations in ɛ with updraft velocity is found to be different in the three main influence regimes. In the updraft velocity main influence regime, vigorous collision–coalescence due to stronger w results in a shift in the cloud droplet number concentration spectrum toward larger droplets, and the average cloud droplet radius increases, but the spectral width is less variable, so ε decreases. In the joint influence regime, stronger cloud droplet evaporation due to the stronger dragging effect of large cloud droplets widens the spectrum, mainly by reducing the cloud droplet number concentration (Nc) of 4–30 μm, and ε increases with the reduction in w. In the aerosol main influence regime, the strongest dragging effect reduces Nc at all radii with decreasing w, and the cloud droplet number concentration spectrum (CDNCS) narrows, which becomes the formation mechanism of the positive correlation between ε and w. Evaporation mainly causes a negative correlation between ε and Nc, but weak evaporation causes the correlation to become positive under the background of high aerosol concentration. At low aerosol concentrations, a strong collision–coalescence effect leads to a negative correlation between Nc and ε, but at high aerosol concentrations, the correlation is the opposite due to a weak collision–coalescence effect.

Heterozygous midnolin knockout attenuates severity of nonalcoholic fatty liver disease in mice fed a Western-style diet high in fat, cholesterol, and fructose.

Although midnolin has been studied for over 20 years, its biological roles in vivo remain largely unknown, especially due to the lack of a functional animal model. Indeed, given our recent discovery that the knockdown of midnolin suppresses liver cancer cell tumorigenicity and that this antitumorigenic effect is associated with modulation of lipid metabolism, we hypothesized that knockout of midnolin in vivo could potentially protect from nonalcoholic fatty liver disease (NAFLD) which has become the most common cause of chronic liver disease in the Western world. Accordingly, in the present study, we have developed and now report on the first functional global midnolin knockout mouse model. Although the overwhelming majority of global homozygous midnolin knockout mice demonstrated embryonic lethality, heterozygous knockout mice were observed to be similar to wild-type mice in their viability and were used to determine the effect of reduced midnolin expression on NAFLD. We found that global heterozygous midnolin knockout attenuated the severity of NAFLD in mice fed a Western-style diet, high in fat, cholesterol, and fructose, and this attenuation in disease was associated with significantly reduced levels of large lipid droplets, hepatic free cholesterol, and serum LDL, with significantly differential gene expression involved in cholesterol/lipid metabolism. Collectively, our results support a role for midnolin in regulating cholesterol/lipid metabolism in the liver. Thus, midnolin may represent a novel therapeutic target for NAFLD. Finally, our observation that midnolin was essential for survival underscores the broad importance of this gene beyond its role in liver biology.NEW & NOTEWORTHY We have developed and now report on the first functional global midnolin knockout mouse model. We found that global heterozygous midnolin knockout attenuated the severity of nonalcoholic fatty liver disease (NAFLD) in mice fed a Western-style diet, high in fat, cholesterol, and fructose, and this attenuation in disease was associated with significantly reduced levels of large lipid droplets, hepatic free cholesterol, and serum LDL, with significantly differential gene expression involved in cholesterol/lipid metabolism.

Droplet Evolution from a Single Hydrophobic Pore in the Diffusion Media of Polymer Electrolyte Fuel Cells: A Conceptual Analysis

Maintaining a well-balanced water distribution is crucial for the operation of polymer electrolyte fuel cells. The water distribution depends to a large extent on the ease of liquid water transport in the diffusion media (DM) and in the flow field (FF) on the cathode side and, especially, on processes in boundary regions between these media. In this article, the droplet dynamics at the DM-FF interface are studied by a mechano-hydrodynamic pore model. The presented treatment allows droplet detachment to be rationalized, in dependence of pore radius and air flow velocity. Large pore radius and high air flow velocity favor droplet detachment during an earlier stage of growth, at which the contact line of the droplet remains pinned at the pore opening while the droplet volume expands during growth. We evaluate the trend of detachment time and detachment height of a droplet. Furthermore, we analyze the influence of the air flow velocity on the time-averaged liquid pressure at the pore exit. The physics governing the flooding behavior of the pore is discussed. The presented model-based analyses provide theoretical insights into material properties and operating conditions that improve water removal.