Channel Blockage Research Articles

Numerical Investigation of the Impact of the Partial Anode Channel Blockage on the Enhanced Mass Transfer and Performance of a Solid Oxide Fuel Cell

This study aims to numerically reveal and assess the influence of inserts of different shapes partially obstructing the anode flow channel on flow characteristics, heat and mass transfer, and planar solid oxide fuel cell (SOFC) performance. To this end, a lattice‐based Boltzmann method is taken. Within this setting, trapezoidal, circular, and triangular shapes and inserts’ heights have been deemed. It turns out that trapezoidal and circular obstacles increase the fuel mass transport to the anode/electrolyte interface and effectively improve the SOFC's power density. As for triangular obstacles, their impact is negligible in terms of performance. Through the findings, it can be stated that it is the trapezoidal design that is better than the other designs. Further, the effect of the inserts’ height has also been assessed to set the optimal performance. It is found that the SOFC performance increases by 4% when using five trapezoidal obstacles with a 90% blocking rate compared to the unobstructed channel. However, in the case of the circular design with five blocks and a 90% blocking rate, the power density improves only about 2.3%. To sum up, improving SOFCs’ power density by designing the anode channel can be adopted to achieve optimal operations.

Optimization strategies to mitigate reactant starvation in a dead-ended hydrogen–oxygen proton exchange membrane fuel cell during cyclic loading

Investigating the dynamic characteristics in hydrogen–oxygen proton exchange membrane fuel cells (PEMFCs) can provide valuable insights into the coupling degradation mechanism present within the fuel cell, which can help avoid reactant starvation and voltage decline. In this study, a recirculation subsystem is integrated into the cathode of the PEMFC to alleviate gas starvation due to water flooding. The impact of pump speed on dynamic loading is also examined. Furthermore, obstacle devices are incorporated into the cell flow channel to enhance mass transfer. The effects of flow channel configuration under the exhaust gas recirculation mode on cell performance and dynamic characteristics are investigated as well. Our findings indicate that blockage of the gas transport channel due to accumulated liquid water is the primary issue during the loading process of PEMFCs. The cathode recirculation pumps set at 600 rpm improves cell performance by 30.6% compared to the dead-ended mode at 1000 mA·cm−2. However, excessively high pump speeds lead to an increase in voltage undershoot during the loading process. Exhaust gas recirculation is found to significantly alleviate gas starvation and water flooding during the cyclic loading process and the cathode recirculation is the primary mitigation strategy for improving dynamic characteristics.

Expression of the ether-a-gò-gò-related gene 1 channel during B and T lymphocyte development: role in BCR and TCR signaling.

The functional relevance of K+ and Ca2+ ion channels in the "Store Operated Calcium Entry" (SOCE) during B and T lymphocyte activation is well proven. However, their role in the process of T- and B- cell development and selection is still poorly defined. In this scenario, our aim was to characterize the expression of the ether à-go-go-related gene 1 (ERG1) and KV1.3 K+ channels during the early stages of mouse lymphopoiesis and analyze how they affect Ca2+signaling, or other signaling pathways, known to mediate selection and differentiation processes of lymphoid clones. We provide here evidence that the mouse (m)ERG1 is expressed in primary lymphoid organs, bone marrow (BM), and thymus of C57BL/6 and SV129 mice. This expression is particularly evident in the BM during the developmental stages of B cells, before the positive selection (large and small PreB). mERG1 is also expressed in all thymic subsets of both strains, when lymphocyte positive and negative selection occurs. Partially overlapping results were obtained for KV1.3 expression. mERG1 and KV1.3 were expressed at significantly higher levels in B-cell precursors of mice developing an experimental autoimmune encephalomyelitis (EAE). The pharmacological blockage of ERG1 channels with E4031 produced a significant reduction in intracellular Ca2+ after lymphocyte stimulation in the CD4+ and double-positive T-cell precursors' subsets. This suggests that ERG1 might contribute to maintaining the electrochemical gradient responsible for driving Ca2+ entry, during T-cell receptor signaling which sustains lymphocyte selection checkpoints. Such role mirrors that performed by the shaker-type KV1.3 potassium channel during the activation process of mature lymphocytes. No effects on Ca2+ signaling were observed either in B-cell precursors after blocking KV1.3 with PSORA-4. In the BM, the pharmacological blockage of ERG1 channels produced an increase in ERK phosphorylation, suggesting an effect of ERG1 in regulating B-lymphocyte precursor clones' proliferation and checkpoint escape. Overall, our results suggest a novel physiological function of ERG1 in the processes of differentiation and selection of lymphoid precursors, paving the way to further studies aimed at defining the expression and role of ERG1 channels in immune-based pathologies in addition to that during lymphocyte neoplastic transformation.

Effects of non-isotropic blockage on a tidal turbine modeled with the Actuator-Line method

Blockage effects are a consequence of the interaction between a body and the surrounding boundaries in a constrained flow. For the case of tidal rotors, global blockage (β) is usually defined bythe ratio between the swept area of the rotor and the cross-sectional area of a channel. Increasingblockage tends to increase the limits of power extraction (Garrett and Cummins, 2007), as well asthrust on a rotor through an attendant increase of through-rotor mass flow. While these observations have been studied and demonstrated for isotropic blockage effects (e.g., Zilic de Arcos et al.2020, Bahaj 2007 , Mikkelsen 2002), questions remain regarding the validity of such assumptionsfor non-isotropic blockage in channels with, e.g., rectangular cross-sections with varying aspectratios.
 In this work, we will use CFD simulations to analyze the effect of non-isotropic blockage on atidal rotor. The study aims to explore these effects using an Actuator-Line representation of anaxial-flow rotor, simulated under different blockage ratios (1 %, 5 %, 10%, and 19.7 %), aspectratios (0.25, 0.5, 0.75, and 1), and tip speed ratios (4, 5, 6, and 7). A total of 64 cases will beconsidered. For each simulated case, the power, thrust, and spanwise force distributions will beextracted as functions of time, and used to understand the effect of blockage on the performanceof tidal rotors.
 Our preliminary results, in agreement with existing literature, indicate that blockage affectswake development, as seen in Figure , along with power and thrust. These results, for a constantaspect ratio, show power increases up to 26 % for a blockage of 20 %. The bulk of the simulationmatrix, including the different aspect ratios, is currently under production and is expected to beready before the paper submission deadline.
 
 ReferencesGarrett, C., Cummins, P. (2007). The efficiency of a turbine in a tidal channel. Journal of fluidmechanics, 588, 243-251.Zilic de Arcos, F., Tampier, G., Vogel, C. R. (2020). Numerical analysis of blockage correctionmethods for tidal turbines. Journal of Ocean Engineering and Marine Energy, 6, 183-197Bahaj, A. S., Molland, A. F., Chaplin, J. R., Batten, W. M. J. (2007). Power and thrust measurements of marine current turbines under various hydrodynamic flow conditions in a cavitationtunnel and a towing tank. Renewable energy, 32(3), 407-426.Mikkelsen, R., Sørensen, J. N. (2002). Modelling of wind turbine blockage. In 15th IEAsymposium on the aerodynamics of wind turbines, FOI Swedish Defence Research Agency.
 

Effects of ultrasonic oscillations on permeability of rocks during the paraffinic oil flow

The paper shows that depending on the degree of blockage of the pore space due to paraffin precipitation the ultrasonic treatment has different effects. If a part of permeable channels is irreversibly deteriorated, then the activation of elastic oscillations contributes to postponing the moment of blocking the remaining part and helps to maintain the oil flow through a sample at a constant level. Without additional means an ultrasonic treatment does not have a significant effect in the case of strong blockage of permeable channels. If elastic oscillations are imposed on the rock and liquid at the initial moment of flow, then the porous space of the rock will be preserved from the precipitation of paraffins.

Oxygen plasma assisted room temperature bonding for manufacturing SU-8 polymer micro/nanoscale nozzle

Abstract Electrohydrodynamic-jet (E-jet) printing is an on-demand additive manufacturing method that allows various functional materials to be directly deposited on the target substrate. Many theoretical and experimental results indicate that E-jet has scale effect, and reducing the inner diameter of the nozzle can effectively improve printing resolution. Herein, a method for fabricating SU-8 polymer micro/nanoscale nozzle by oxygen plasma assisted room temperature bonding was proposed. It can prevent channel deformation and blockage caused by excessive bonding temperature. The surface modification parameters of silicon nano-mold were optimized, the influence of hot embossing parameters on the replication precision of nano patterns was investigated, the effect of UV lithography parameters on the micro and nanochannel was analyzed, the relationship between the oxygen plasma treatment parameters on the contact angle of SU-8 was revealed, the influence of bonding pressure on the morphology of the nanochannel was discussed, and the bonding principle at room temperature was deeply analyzed. This method can fabricate SU-8 polymer micro/nanoscale nozzle with low cost and high precision, and provide a new idea for the realization of room temperature bonding to manufacture SU-8 polymer nozzle.

Migration of the Cu species by alkali metal potassium on the reaction of NH3 with NOx over Cu-SSZ-13 catalyst

Cu/SSZ-13 catalyst, as an efficient SCR catalyst, may suffer from the environment of complex alkali metal poisoning. Therefore, it is crucial to understand the effect of impregnation alkali metal on a catalyst for NH3-SCR. To explore the role of impregnation potassium on Cu/SSZ-13 catalysts, experiments were carried out to investigate fresh and different potassium content on Cu/SSZ-13 catalysts combined with the simulated gas experimental platform and some characterization methods. The results showed that the NOx conversion was slightly affected by the impregnation potassium content of 0.5 wt%. However, a notable decline in catalytic activity, particularly at elevated temperatures, was observed when the potassium content was increased to 3.0 wt%. In addition, XRD and BET results showed that the surface area of the catalyst was decreased by the blockage of pore channels, especially for the impregnation content of 3.0 wt% potassium, but the structure of the catalyst was not collapsed. The XPS characterization results showed that the impregnation of potassium led to the transformation of isolated Cu2+ species into CuO species on the surface of the catalyst. This transformation was driven by the smaller size of K+ ions, replacing Cu2+ species at exchange sites and forming CuO clusters at higher temperatures. However, the formation of CuO clusters led to a blockage in molecular sieve channels, resulting in decreased catalyst activity.

Digital light processing 3D printing for microfluidic chips with enhanced resolution via dosing- and zoning-controlled vat photopolymerization

Conventional manufacturing techniques to fabricate microfluidic chips, such as soft lithography and hot embossing process, have limitations that include difficulty in preparing multiple-layered structures, cost- and labor-consuming fabrication process, and low productivity. Digital light processing (DLP) technology has recently emerged as a cost-efficient microfabrication approach for the 3D printing of microfluidic chips; however, the fabrication resolution for microchannels is still limited to sub-100 microns at best. Here, we developed an innovative DLP printing strategy for high resolution and scalable microchannel fabrication by dosing- and zoning-controlled vat photopolymerization (DZC-VPP). Specifically, we proposed a modified mathematical model to precisely predict the accumulated UV irradiance for resin photopolymerization, thereby providing guidance for the fabrication of microchannels with enhanced resolution. By fine-tuning the printing parameters, including optical irradiance, exposure time, projection region, and step distance, we can precisely tailor the penetration irradiance stemming from the photopolymerization of the neighboring resin layers, thereby preventing channel blockage due to UV overexposure or compromised bonding stability owing to insufficient resin curing. Remarkably, this strategy can allow the preparation of microchannels with cross-sectional dimensions of 20 μm × 20 μm using a commercial printer with a pixel size of 10 μm × 10 μm; this is significantly higher resolution than previous reports. In addition, this method can enable the scalable and biocompatible fabrication of microfluidic drop-maker units that can be used for cell encapsulation. In general, the current DZC-VPP method can enable major advances in precise and scalable microchannel fabrication and represents a significant step forward for widespread applications of microfluidics-based techniques in biomedical fields.

Physiological Study of Srotorodha in Relation to Aam and its Management by Srotovishodhana Karma of Vyana Vayu

One of the primary causes of disease is an aggravated Dosha. These aggravated Doshas lodge in the various channels, causing abnormalities or channel blockages, which ultimately result in a variety of diseases. The genesis of diseases is triggered by any Srotas disturbances, whether it be structurally or functionally. Sroto-Vaigunya is the state in which the Srotas are vulnerable to pathological changes or beneficial movements that can result in a disease. Atipravrutti, Sanga, Siragranthi, and Vimargagam are the four types of Srotodusti Lakshana that are observed. The quality and function of the dependent tissues are disrupted or reduced as a result of channel blockage. Our bodies' ongoing metabolic process is called metabolism. During such metabolic changes, the body naturally releases free radicals, which are ultimately harmful to our bodies. They are the ones who cause us to age and begin the process of ageing, during which the body's physical and mental capacity decrease.

Aerobic Exercise Training Improves Calcium Handling and Cardiac Function in Rats with Heart Failure Resulting from Aortic Stenosis.

Aerobic exercise training (AET) has been used to manage heart disease. AET may totally or partially restore the activity and/or expression of proteins that regulate calcium (Ca2+) handling, optimize intracellular Ca2+ flow, and attenuate cardiac functional impairment in failing hearts. However, the literature presents conflicting data regarding the effects of AET on Ca2+ transit and cardiac function in rats with heart failure resulting from aortic stenosis (AoS). This study aimed to evaluate the impact of AET on Ca2+ handling and cardiac function in rats with heart failure due to AoS. Wistar rats were distributed into two groups: control (Sham; n = 61) and aortic stenosis (AoS; n = 44). After 18 weeks, the groups were redistributed into: non-exposed to exercise training (Sham, n = 28 and AoS, n = 22) and trained (Sham-ET, n = 33 and AoS-ET, n = 22) for 10 weeks. Treadmill exercise training was performed with a velocity equivalent to the lactate threshold. The cardiac function was analyzed by echocardiogram, isolated papillary muscles, and isolated cardiomyocytes. During assays of isolated papillary muscles and isolated cardiomyocytes, the Ca2+ concentrations were evaluated. The expression of regulatory proteins for diastolic Ca2+ was assessed via Western Blot. AET attenuated the diastolic dysfunction and improved the systolic function. AoS-ET animals presented an enhanced response to post-rest contraction and SERCA2a and L-type Ca2+ channel blockage compared to the AoS. Furthermore, AET was able to improve aspects of the mechanical function and the responsiveness of the myofilaments to the Ca2+ of the AoS-ET animals. AoS animals presented an alteration in the protein expression of SERCA2a and NCX, and AET restored SERCA2a and NCX levels near normal values. Therefore, AET increased SERCA2a activity and myofilament responsiveness to Ca2+ and improved the cellular Ca2+ influx mechanism, attenuating cardiac dysfunction at cellular, tissue, and chamber levels in animals with AoS and heart failure.

Effects of potassium channel blockage on inverse stochastic resonance in Hodgkin-Huxley neural systems

Effects of potassium channel blockage on inverse stochastic resonance in Hodgkin-Huxley neural systems

Numerical Assessment of Flow Energy Harvesting Potential in a Micro-Channel

A micro-energy harvesting device proposed in the literature was numerically studied. It consists of two bluff bodies in a micro-channel and a flexible diaphragm at its upper wall. Vortex shedding behind bodies induces pressure fluctuation causing vibration of the diaphragm that converts mechanical energy to electrical by means of a piezoelectric membrane. Research on enhancing vortex shedding was justified due to the low power output of the device. The amplitude and frequency of the unsteady pressure fluctuation on the diaphragm were numerically predicted. The vortex shedding severity was mainly assessed in terms of pressure amplitude. The CFD model set-up was described in detail, and appropriate metrics to assess the energy harvesting potential were defined. Several 2D cases were simulated to study the effect of the inlet Reynolds number and channel blockage ratio on the prospective performance of the device. Furthermore, the critical blockage ratio leading to the vortex shedding suppression was sought. A higher inlet velocity for a constant blockage ratio was found to enhance vortex shedding and the pressure drop. Great blockage ratio values but lower than the critical ones seemed to provide great pressure amplitudes at the expense of a moderate pressure drop. There is evidence that the field is fruitful for further research and relevant directions were provided.

Validation of RANS simulations on a 61-pin wire-wrapped fast-reactor fuel assembly under the presence of localized blockages

One of the fuel assembly designs considered for liquid metal-cooled fast reactors (LMFR) uses wires helically wrapped around fuel pins as spacers. The understanding of the coolant behavior in LMFR fuels under the influence of a partially blocked flow area is required for a correct safety assessment of the Nuclear Power Plant. Accumulation of debris or cladding deformation may generate a partial or total flow blockage of coolant channels at different locations. In this paper, Unsteady Reynolds-Averaged Navier-Stokes (URANS) is applied using different turbulence models to predict the axial friction factor under the presence of blockages, placed at different positions on the bundle cross section. The simulated Reynolds number was 17,000. Results are compared with experimental friction factor data produced at the Texas A&M experimental facility. The sensitivity analysis of the RANS turbulence models concluded that the k-∊ Realizable model is the recommended one for this Reynolds number because it presented the minimum relative error with respect to the experimental data that was found below 5%.

Modeling Flow Blockage Accident in Graphite-Moderated Molten Salt Reactors

Fuel channel flow blockage is a postulated accident scenario in graphite-moderated molten salt reactors (MSRs), caused by debris partially obstructing the flow in a hole inside a graphite moderator brick. This obstruction produces an increase in the fuel salt bulk temperatures in the blocked channel, resulting in a significant fraction of the deposited fission power being conducted through graphite from the blocked channel to the surrounding unblocked channels. In the blocked channel, a combination of forced convection and natural convection takes place, the latter being dominant at very strong flow rate reductions. At full blockage (with the fragment completely obstructing the flow), because of the poor thermal conductivity of fuel salt, correct estimation of the natural convection impact on heat transfer between the channel bulk and the walls is fundamental to determine whether boiling conditions are reached in the blocked channel. The proposed assessing approach, developed in collaboration with ThorCon in the frame of the ThorCon reactor core design and optimization, is presented in this work. Results from a case study based on the molten salt breeder reactor (MSBR) design and operating conditions are presented and discussed. These analyses show that with respect to full blockage accidents in other reactor types, the consequences of full channel blockage accidents in graphite-moderated MSRs are milder. For graphite-moderated MSRs, the main mechanical limits during the accident arise in thermal stresses in the graphite brick. Graphite thermal and mechanical properties, namely, bulk modulus, thermal expansion coefficient, ultimate strength, and thermal conductivity, are severely impacted by neutron irradiation through the life of the graphite. All these effects are taken into account in the current analysis and are discussed in the present work.

Mechanisms of swelling inhibition and seepage promotion of weathered crust elution-deposited rare earth ore by hydroxypropyl methyl cellulose

In-situ leaching process of weathered crust elution-deposited rare earth ore (WCE-DREO) often faces problems such as poor permeability and occurrence of landslides. The main reasons are the swelling of clay minerals by water absorption and blockage of seepage channels by fine particles. This study proposed using hydroxypropyl methyl cellulose (HPMC) as a novel green swelling inhibitor with the combination of ammonium sulfate ((NH4)2SO4) as an efficient composite leaching agent. The swelling inhibition performance of HPMC on swelling inhibition was evaluated through linear swelling tests and mud ball immersion tests. The mechanisms of HPMC on swelling inhibition and seepage promotion were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Scanning electron microscopy (SEM), Surface area analysis (BET), X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TGA), and the contact angle, zeta potential and particle size distribution were characterized. The results indicated that HPMC showed a good performance on swelling inhibition, which improved with the increase of HPMC concentration. HPMC expels the water from the interlayer. Moreover, HPMC adsorbs onto the surface of clay minerals by hydrogen bonding to form a hydrophobic film, which can prevent the clay minerals from hydration swelling. Due to the electric neutrality property of HPMC, the electrostatic repulsion of clay minerals can be reduced. Therefore, the fine particles of the clay minerals can be bridged to form larger particles by the long carbon chain of HPMC which leads to expansion of the seepage channels as well as the improvement of the permeability of the ores. According to the column leaching tests, the novel leaching agent composed of 0.05 wt% HPMC and 2 wt% (NH4)2SO4 not only showed a good leaching capacity of rare earth, but also inhibited the swelling of clay and enhanced the seepage when comparing with traditional leaching agent ((NH4)2SO4). Developing a novel leaching agent benefits the green, safe and high-efficiency exploitation of WCE-DREO.

Correlation of Serum Calcium with Enzymes Aspartate Aminotransfrase, Creatine Kinase and Mastitis in Postpartum Period in Dairy Cattle

Mastitis is inflammation of udder and its chances increases in hypocalcemia cases because sphincters of teat are loosened due to calcium-ion channel blockage. Cows those suffered milk fever have 8 times more chances of developing mastitis than other cows which haven’t suffered hypocalcaemia. The values of AST and CK are high in downer cows due to hypocalcemia as compared to healthy cows. Subclinical hypocalcaemia is one of the major complication occurring just after parturition in local and exotic breeds of cattle in Pakistan. It weakens the immune system of dairy animal and also decreases the production potential of animals thus causing serious economic losses in terms of decrease milk production of animal, decrease earning of animal and increased treatment cost due to secondary infection like mastitis occurred due to weakened immune function. The current study was aimed to the correlation of serum calcium with enzymes Creatine Kinase and Aspartate amino transferase and mastitis in postpartum period in dairy cattle. A total of 50 cattle (n=50) just after parturition were included in this study. The cattle were sampled in two ways. Firstly, 10ml blood was drawn aseptically into clot activator vacutainers from jugular vein. Secondly milk samples were taken from all four teats. First 2 milk strips were discarded and next strips were collected in aseptic test tubes. The samples were transported to Pathology laboratory, Department of Pathology, University of Veterinary and Animal Sciences, Lahore maintaining the cold chain and stored at -20 0C till further analysis. Correlation between calcium and creatin kinase comes out to be 0.279 which is weak positive correlation. Correlation between calcium and aspartate aminotransferase is also weak and comes out to be 0.111. Similarly, correlation between calcium and SCC also weak and comes out to be 0.193.This is the first study of correlation of calcium with CK, AST and SCC in dairy cattle after postpartum period.
 

Design of ion channel blocking, toxin-like Kunitz inhibitor peptides from the tapeworm, Echinococcus granulosus, with potential anti-cancer activity

Over-expression of K+ channels has been reported in human cancers and is associated with the poor prognosis of several malignancies. EAG1, a particular potassium ion channel, is widely expressed in the brain but poorly expressed in other normal tissues. Kunitz proteins are dominant in metazoan including the dog tapeworm, Echinococcus granulosus. Using computational analyses on one A-type potassium channel, EAG1, and in vitro cellular methods, including major cancer cell biomarkers expression, immunocytochemistry and whole-cell patch clamp, we demonstrated the anti-tumor activity of three synthetic small peptides derived from E. granulosus Kunitz4 protease inhibitors. Experiments showed induced significant apoptosis and inhibition of proliferation in both cancer cell lines via disruption in cell-cycle transition from the G0/G1 to S phase. Western blotting showed that the levels of cell cycle-related proteins including P27 and P53 were altered upon kunitz4-a and kunitz4-c treatment. Patch clamp analysis demonstrated a significant increase in spontaneous firing frequency in Purkinje neurons, and exposure to kunitz4-c was associated with an increase in the number of rebound action potentials after hyperpolarized current. This noteworthy component in nature could act as an ion channel blocker and is a potential candidate for cancer chemotherapy based on potassium channel blockage.

Assessment of Soil Vulnerability Index for surface runoff in Kawal watershed, Bintan island

The quantity of transformed land cleared after deforestation in the basin demonstrates the severity of soil erosion on Bintan Island. Deposition of eroded material causes eutrophication, blockage, and silting of channels and water bodies, as well as flooding in lowlands and coasts. Heavy rainfall and sparse cover of vegetation ravaged the structure of soil, further preventing it from storing and absorbing water, which increased surface runoff and had an impact on rising erosion rates. The goal of this study was to evaluate the vulnerability class of surface runoff using SVI. The SVI class is based on slope extracted from the digital elevation model, hydrologic soil group, and soil erodibility. The results of the SVI classification for mapping surface runoff susceptibility resulted in areas with low criteria of 7% (664 ha), medium 14% (1,229 ha) and high 79% (7,069 ha). The major influences on the high vulnerability of surface runoff in the Kawal watershed on Bintan island appeared to be rainfall, soil type, land use, and slope gradient.

Establishment of a Perfusion Process with Antibody-Producing CHO Cells Using a 3D-Printed Microfluidic Spiral Separator with Web-Based Flow Control.

Monoclonal antibodies are increasingly dominating the market for human therapeutic and diagnostic agents. For this reason, continuous methods-such as perfusion processes-are being explored and optimized in an ongoing effort to increase product yields. Unfortunately, many established cell retention devices-such as tangential flow filtration-rely on membranes that are prone to clogging, fouling, and undesirable product retention at high cell densities. To circumvent these problems, in this work, we have developed a 3D-printed microfluidic spiral separator for cell retention, which can readily be adapted and replaced according to process conditions (i.e., a plug-and-play system) due to the fast and flexible 3D printing technique. In addition, this system was also expanded to include automatic flushing, web-based control, and notification via a cellphone application. This set-up constitutes a proof of concept that was successful at inducing a stable process operation at a viable cell concentration of 10-17 × 106 cells/mL in a hybrid mode (with alternating cell retention and cell bleed phases) while significantly reducing both shear stress and channel blockage. In addition to increasing efficiency to nearly 100%, this microfluidic device also improved production conditions by successfully separating dead cells and cell debris and increasing cell viability within the bioreactor.

Evaluation of rosuvastatin-induced QT prolongation risk using real-world data, in vitro cardiomyocyte studies, and mortality assessment

Drug-induced QT prolongation is attributed to several mechanisms, including hERG channel blockage. However, the risks, mechanisms, and the effects of rosuvastatin-induced QT prolongation remain unclear. Therefore, this study assessed the risk of rosuvastatin-induced QT prolongation using (1) real-world data with two different settings, namely case–control and retrospective cohort study designs; (2) laboratory experiments using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM); (3) nationwide claim data for mortality risk evaluation. Real-world data showed an association between QT prolongation and the use of rosuvastatin (OR [95% CI], 1.30 [1.21–1.39]) but not for atorvastatin (OR [95% CI], 0.98 [0.89–1.07]). Rosuvastatin also affected the sodium and calcium channel activities of cardiomyocytes in vitro. However, rosuvastatin exposure was not associated with a high risk of all-cause mortality (HR [95% CI], 0.95 [0.89–1.01]). Overall, these results suggest that rosuvastatin use increased the risk of QT prolongation in real-world settings, significantly affecting the action potential of hiPSC-CMs in laboratory settings. Long-term rosuvastatin treatment was not associated with mortality. In conclusion, while our study links rosuvastatin use to potential QT prolongation and possible influence on the action potential of hiPSC-CMs, long-term use does not show increased mortality, necessitating further research for conclusive real-world applications.