Viscosity Levels Research Articles

Application of Fuzzy Logic to Motorcycle Oil Change Cycle with 10W 30 Oil Viscosity

Oil is a fluid that serves to lubricate the engine, so that friction between engine components is relatively small. Oil changes are based on mileage, oil volume, and oil viscosity levels which usually vary depending on the needs of the vehicle's engine. Most riders are often late and do not even know the routine time of oil changes so that the user's motorcycle engine feels damaged. The application of fuzzy logic has become an important approach in modeling the complex and ambiguous system of motorcycle oil change periods with 10W 30 oil viscosity. The purpose of this study is to determine the application of fuzzy logic in determining the optimal oil. exchange interval. Oil is based on factors such as mileage, oil volume, and oil viscosity when viewed from motorcycle use. To represent these variables using fuzzy sets, a fuzzy logic control system was developed that takes into account oil wear and motorcycle operating conditions which was implemented using the mamdani method and calculated using matlab software. The results showed that oil change intervals tailored to operating conditions and the environment can improve engine performance, reduce maintenance costs and extend component life.

Are metal-based antibacterial gels a potential alternative for disinfection in contemporary endodontics?

This study aimed to assess the effectiveness of a novel antimicrobial gel, containing copper and silver nanoparticles, for use in root canal disinfection. Copper and silver-based gels were created in-house, using a support network of biocompatible polymers, including polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG). Six experimental groups were created, three containing silver ions and three copper ions, where the PVA, PVP and PEG ratios were also adjusted in each group to test the gel's physical state. One control contained no metal nanoparticles. The gels surface characteristics, roughness, mechanical properties, and flowability, were characterised using a combination of atomic force microscopy, scanning electron microscopy, transmission electron microscopy and Rheometery. Further biological testing measured the gels cytotoxicity levels, using human periodontal ligament cells, and the anti-microbial effects against E. Faecalis and a multi-species bacteria biofilm. Each gel demonstrated high levels of viscosity, which was lowered in gels containing a reduced PVA concentration. The overall antimicrobial properties of the gels increased in those with a higher dissolution, lower porosity, and reduced surface roughness. Copper nanoparticles were shown to be significantly more effective against E. Faecalis, compared with silver. Gels containing higher PVA levels, and silver nanoparticles, had greater toxicity levels against human cells, however, testing was not possible for most experimental groups as the gels dissolved before measurements took place. The antimicrobial properties of all gel formulations were significantly less effective than sodium hypochlorite (after 1 h), but a similar outcome was detected in comparison with calcium hydroxide (after 7 days). Developing an antimicrobial gel is highly dependent upon numerous compositional factors, where development is still at the early stages. The use of copper nanoparticles appeared to be more appropriate for use in canal disinfection, compared with silver that also had higher levels of human cell toxicity. The ratios selected for the biocompatible polymers had a critical impact on the physical state, antimicrobial, and toxicity levels. At present, antimicrobial gels are not as effective as sodium hypochlorite.

Study on Hydraulic Fracture Propagation of Strong Heterogeneous Shale Based on Stress‐Seepage Damage Coupling Model

ABSTRACTThe developed laminar structure of shale makes it possess obvious anisotropic characteristics, and these anisotropic characteristics are one of the important factors leading to the strong and weak heterogeneous properties of shale. Additionally, there is a common phenomenon where the propagation of hydraulic fracture heights is limited in the hydraulic fracturing process of strongly heterogeneous shale reservoirs. To clarify the reasons for the limited height propagation of hydraulic fractures in strongly heterogeneous shale reservoirs, numerical simulation methods were used to study the propagation patterns of hydraulic fractures in shale reservoirs under different levels of anisotropy, flow rate, viscosity, and stress differences. The results show that as the anisotropy value increases and the heterogeneity becomes stronger, it becomes more difficult for hydraulic fractures to expand along the fracture height direction, and the fracture width at the fracture opening becomes larger. For strongly heterogeneous shale reservoir, the hydraulic fracture height can be increased within a certain range by increasing the flow rate, viscosity, and stress difference. When the upper limit value is exceeded, the hydraulic fracture height of the strong heterogeneous shale reservoir gradually becomes stable, and the increasing trend is no longer obvious. The strong or weak heterogeneity caused by the inherent anisotropic characteristics of shale reservoirs affects the development and transformation effectiveness of shale reservoirs. The research in this article will provide some reference material and guidance for the efficient development of shale reservoirs.

Development of 3D Printed Scaffolds Containing Decellularized Plants and Investigation of Their Basic Cell Interactions

The decellularization process fundamentally removes the cellular content of the tissue (nuclear material and other nucleic acid components) without disrupting the structural integrity of the tissue. It is an effective approach, especially for obtaining three-dimensional (3D) biomaterials composed of the extracellular matrix (ECM), which provides tissue biomechanical support. In the literature, studies have shown that after the decellularization process, animal-derived decellularized tissues have been combined with various biopolymers to prepare composite scaffolds using different techniques. In recent years, due to their structural features, decellularization studies of plant-derived tissues have also gained prominence alongside animal tissues. In this study, succulent plants were chosen as the plant tissue, and the purpose was to prepare hybrid scaffolds by combining decellularized succulent tissues with alginate structures. The study aimed to investigate the fundamental cell-material interactions and cartilage-specific differentiation parameters using mesenchymal stem cells. Succulent plant leaves were decellularized using a solution containing Triton X-100 and SDS. The water-retaining parts were separated from other tissues, lyophilized, and turned into a powder. This approach was employed to preserve biomolecules with water-retaining capacity in powdered form. To determine the efficiency of the decellularization process, the quantities of DNA and proteins were assessed and compared. Due to their high water-absorbing capacity, the succulent plants' water-retaining structures were combined with alginate biopolymer at various viscosity levels to prepare an ink suitable for 3D printing. After printing, the resulting scaffolds' degradation and swelling behavior, chemical composition, structural characterization, and thermal properties were examined. In the final phase, a fundamental investigation was carried out on cell-material interactions using L929 mouse fibroblast cells and human mesenchymal stem cells on 3D printed scaffolds. The interactions within the prepared hybrid scaffolds were analyzed through basic cytotoxicity tests.

POWDERED FOODSTUFFS INTENDED FOR CHILD FEEDING IN UNDERDEVELOPED COUNTRIES: RISKS OF CONTAMINATION BY SALMONELLA AND ESCHERICHIA

Introduction: Powdered infant milk play a crucial role in infant nutrition when breastfeeding is not available. However, both dairy companies and consumers encounter challenges related to the physicochemical stability, as well as the microbiological quality throughout storage/ distribution. Objective: Study aimed to evaluate microbiological quality and physicochemical stability of eleven imported first-age milk samples from various brands, collected in Algiers city, during spring season. Methods: Samples stability will be assessed by various physicochemical tests (density, pH, titratable acidity, viscosity, protein and lactose levels, etc). Microbiological quality will be explored by research involving colony forming units (CFU) counting on conventional selective culture media, the evaluation of the pathogenic floras/species. Salmonella Enumeration, in addition to conventional method, on three differential selective broths. Results & discussion: Chemical tests indicated that samples remained stable, with the following mean values: Density (1.024), pH (6.655), Acidity (17.628), Viscosity (2.574), Conductivity (1805.72 µS/cm), Total Dissolved Solids (TDS) (85 mg/L), Protein Content (1.66 g/100ml of milk), and Lactose Content (1.5509 g/100ml of milk). Microbiological analysis, apart from absence of Staphylococcus, Cronobacter, revealed following results: yeasts and molds were present in 36.36 % (4/11) of samples, total bacterial count exceeded standards in 27.27 % (3/11) of samples, total coliforms were observed in 9.09 % (2/11) of samples, total fecal coliforms were detected in 9.09 % (1/11) of samples, Escherichia coli was present in 9.09 % (1/11) and D-Streptococcus was found in 18.18 % (2/11) of samples. Research Implications: The entire set samples demonstrated chemical stability throughout storage and distribution, with no packaging or labeling defects noted. However, microbiological quality sample’s fell below local/international standards. In light of these findings, further investigation is warranted through expanded sampling approach, targeting additional PIF brands, conducting a wider array of physicochemical and toxicological tests, and examining a wider of bacterial flora/species.

Polysaccharide-Based Fat Replacers in the Functional Food Products

The functional properties of food products, in addition to enrichment with functional components, can also be achieved by reducing the content of certain components such as sugars and fats, that is, by reducing the energy content of the product. Thus, the development of functional food products is aimed at various low-energy products, especially products with a reduced fat content, which normally represent the most concentrated source of energy. Fat replacers should simulate the functional properties of the fat. Polysaccharide-based fat replacers include a variety of native starches, modified starches, maltodextrins, cellulose and cellulose derivatives, polydextrose, inulin, pectin, other dietary fibers, and hydrocolloids. Technological properties required for the application of carbohydrate-based fat replacers are water-holding capacity, a certain level of viscosity, required form and particle size, three-dimensional networking and gel-forming ability, sensory abilities such as spreadability, softness, greasiness feeling in the mouth, and other fat-like properties. These fat replacers are usually applied in combinations with the aim of achieving all desired properties normally provided by fats in foods. In the contemporary literature, there are many examples of their application in different food products, including baked goods, meats, dairy products, and emulsion food systems, successfully reducing the fat content with or without minor alterations in the rheology or sensory features of food products. In summary, polysaccharides-based fat replacers offer an effective method for fat reduction in different food products along with enhancing the health benefits of reduced-fat foods.

Single fluorescent probe reveals glutathione-viscosity crosstalk in the endoplasmic reticulum during ferroptosis and extracellular vesicles in synergistic ferroptosis-apoptosis

Ferroptosis is an iron-dependent cell death triggered by lipid peroxidation accumulation, representing a redox imbalance in cells. The increased knowledge of ferroptosis has led to various potential strategies to develop new cancer therapies, such as synergistic ferroptosis-apoptosis. The endoplasmic reticulum (ER) is the major hub for lipid metabolism in cells and plays a central role in lipid peroxidation. Glutathione (GSH) and viscosity levels in ER are important parameters for intracellular redox homeostasis, which remain unclear in ferroptosis and synergistic ferroptosis-apoptosis. This study developed an ER-targeting fluorescent probe (MMPY) with a dual-emission response to GSH and viscosity. Fluorescent cell imaging using MMPY revealed different GSH-viscosity crosstalk in the ER for the four ferroptosis pathways induced by erastin, RSL3, FIN56, and FINO2. GSH and viscosity changes in the ER during synergistic ferroptosis-apoptosis were also investigated. Interestingly, the new types of extracellular vesicles were observed during the synergistic process, which burdened the ER fragments with different GSH contents.

A Tandem-Locked Fluorescent Probe Activated by Hypoxia and a Viscous Environment for Precise Intraoperative Imaging of Tumor and Instant Assessment of Ferroptosis-Mediated Therapy.

Noninvasive fluorescence detection of tumor-associated biomarker dynamics provides immediate insights into tumor biology, which are essential for assessing the efficacy of therapeutic interventions, adapting treatment strategies, and achieving personalized diagnosis and therapy evaluation. However, due to the absence of a single biomarker that effectively reflects tumor development and progression, the currently available optical diagnostic agents that rely on "always-on" or single pathological activation frequently show nonspecific fluorescence responses and limited tumor accumulation, which inevitably compromises the accuracy and reliability of tumor imaging. Herein, based on intramolecular charge transfer (ICT) and twisted intramolecular charge-transfer (TICT) hybrid mechanisms, we report a tandem-locked probe, NTVI-Biotin, for simultaneously specific imaging-guided tumor resection and ferroptosis-mediated tumor ablation evaluation under the coactivation of nitro reductase (NTR)/viscosity. The dual-stimulus-responsive design strategy ensures that NTVI-Biotin exclusively activates near-infrared (NIR) fluorescence signals upon interaction with both NTR and elevated viscosity levels through triggering ICT on while inhibiting the TICT process. Meanwhile, functionalization with a tumor-targeting hydrophilic biotin-poly(ethylene glycol) moiety enhances tumor accumulation. The probe's dual-response and tumor-targeting design minimizes nonspecific tissue activation, allowing for precise tumor identification and lesion removal with a superior tumor-to-normal tissue (T/N > 6) ratio. More importantly, NTVI-Biotin was capable of evaluating ferroptosis-mediated chemotherapeutics by real-time monitoring of the alternations of NTR/viscosity levels. The results reveal that the increased tumor signals of NTVI-Biotin following the combination of ferroptosis and chemotherapy correlate well with the tumor growth inhibition, demonstrating the potential of NTVI-Biotin to assess therapeutic efficacy.

In situ observation of mitochondrial viscosity in liver of mice with drug-induced liver injury by near-infrared fluorescence imaging

Drug-induced liver injury (DILI) has emerged as among of the undesirable drug effects, posing significant threats to human health. However, in clinical practice, there remains a shortage of dependable and pre-diagnosis tools for DILI. Numerous studies indicated that the elevated intrahepatic viscosity levels were closely linked to the onset and progression of DILI. Therefore, establishing reliable tools to monitor mitochondrial viscosity are crucial for prompt diagnosis of DILI in situ. Herein, we proposed a new near-infrared (NIR) fluorescence probe (Wyry-M-V) for detecting mitochondrial viscosity, in which consisted of xanthene, multiple viscosity-responsive rotors (diphenyl, vinyl cyanide, and benzyl chloride) and mitochondrial targeting site (pyridinium cation). Furthermore, the Wyry-M-V was triumphantly utilized in mitochondrial viscosity imaging upon treatment with lipopolysaccharide, nystatin and acetaminophen (APAP). Notably, based on the advantages of NIR emission wavelength, the Wyry-M-V was resoundingly used for the detection of mitochondrial viscosity in APAP-induced DILI mice model.

The Effects of High-Intensity Interval Training with Different Duration on Fibrinogen and Plasma Viscosity in Sedentary Male College Students

Background: There have been few investigations into the impact of high-intensity interval training on blood rheology. Objectives: This study aimed to evaluate how high-intensity interval training conducted with different duration affects fibrinogen and plasma viscosity in sedentary young college men. Methods: For this study, 36 healthy male participants were selected and grouped based on their individual characteristics. The groups included a control group (n = 9), a 45-second training group (tr-45; n = 9), a 30-second training group (tr-30; n = 9), and a 15-second training group (tr-15; n = 9). The training regimen comprised six sessions over two weeks, with varying sets (4, 5, 6, 6, 7, 4 respectively) and durations of 15, 30, and 45 seconds for different groups. There was a fixed 4-minute rest interval between each set, with a consistent load of 0.6 on the Wingate cycle ergometer. Blood samples were collected 48 hours before and after the final session to analyze fibrinogen and plasma viscosity levels. Results: There were no significant differences between groups in plasma fibrinogen levels (F3, 32 = 2.303, P = 0.96). However, post-test analysis revealed a significant decrease in plasma fibrinogen in the tr-45 group (P = 0.027) compared to pre-test levels. Plasma viscosity did not significantly change between groups (F3, 32 = 0.651, P = 0.058), but there was a significant interaction between time and group (F3, 40 = 4.43, P = 0.009). Post-test analysis showed a significant decrease in plasma viscosity in the tr-45 (P = 0.010), tr-30 (P = 0.002), and tr-15 (P = 0.003) groups, while it significantly increased in the control group (P = 0.004) compared to pre-test levels. Conclusions: The findings suggest that high-intensity interval training can effectively decrease blood rheology and factors such as fibrinogen and plasma viscosity, with the 45-second HIIT being more efficient. Therefore, incorporating this training into Physical Activity Programs could be beneficial for inactive men.

Fluorescent probe for tumor imaging and prognostic assessment via multi-response to biothiols, viscosity, and pH values

Accurate tumor diagnosis and drug efficacy assessment are crucial aspects of cancer treatment. Tumor cells typically display aberrant levels of biothiols, higher viscosity, and lower acidity compared to normal cells. Thus, precise monitoring of biothiol levels in the intricate cellular environment is essential for early tumor detection. We have developed a novel near-infrared (NIR) fluorescence probe AX-DNBS for the simultaneous detection of biothiols, viscosity, and pH through multi-channel imaging. With the treatment of biothiol, AX-DNBS triggers the release of AX-OH, resulting in enhanced fluorescence emission at 710 nm. Both AX-DNBS and AX-OH exhibit sensitive responses to changes in viscosity, with fluorescence emissions at 475 nm and 640 nm, respectively. In the pH range of 3–10, an increase in alkalinity leads to a ratiometric fluorescence signal of AX-OH with a significant emission red-shift from 640 nm to 710 nm. Significantly, in subsequent biological trials, AX-DNBS proved effective in monitoring alterations in biothiol levels, viscosity, and pH within live cells, facilitating the diagnosis of tumors and the evaluation of the therapeutic effects of paclitaxel in tumor mice models.

Effect of macromolecules on the viscosity of whole condensed milk

The viscosity of a fluid refers to the resistance to flow, such as in the case of whole condensed milk. Condensed milk is a product created by partially dehydrating milk, concentrated milk, or reconstituted milk, and then sugar is added. Its fat and protein content can be adjusted to meet specific characteristics. The aim of this study was to evaluate the effect of macromolecules on the viscosity of various brands of whole condensed milk. The brands of whole condensed milk analyzed were classified as LCA, LCB, LCC, LCD, and LCE, with a total of 50 samples from different batches. The viscosity was measured using the Ford cup method, which was validated through tests for linearity, detection limit, quantification limit, and repeatability. The physicochemical tests included viscosity, soluble solids (oBrix), moisture, protein, lipids, RMF, carbohydrates, total caloric value, and SNG. The main findings showed that the LCC, LCD, and LCE brands had high levels of macromolecules (protein, lipids, and carbohydrates) and viscosity. Consequently, it was concluded that high concentrations of macromolecules in whole condensed milk result in increased viscosity of the product.

A multifunctional fluorescent probe for monitoring of SO2 and viscosity and its application in food, ferroptosis, and bioimaging

Inflammation is an intrinsic defense mechanism of organisms against tissue injury, characterized by biological pathways such as autophagy, depolarization, and endogenous sulfite production. Ferroptosis, a newly identified form of iron-dependent programmed cell death, leads to the accumulation of excessive lipid peroxides, resulting in changes in viscosity and SO₂ levels. Investigating the dynamic relationship between SO₂ and viscosity in these two conditions is crucial for elucidating the precise regulatory mechanisms of inflammation and ferroptosis. Here, we developed a fluorescent probe, named CNNP, which possesses dual targeting capabilities for lipid droplets and mitochondria. This innovative probe facilitates the simultaneous and precise detection of both SO₂ and viscosity, utilizing distinct emission wavelengths without cross-talk interference. Furthermore, we successfully employed this probe to determine bisulfite levels in food and herbal medicine samples, achieving high recovery rates (99.2 %–104.2 %), thereby demonstrating its practical utility. Notably, CNNP enables both exogenous and endogenous imaging of SO₂ and viscosity within cells. We observed subtle fluctuations in SO₂ levels and viscosity during inflammation and ferroptosis, as evidenced by abnormal changes in process parameters in both in vivo and in vitro levels. These findings introduce new perspective for the diagnosis and treatment of these pathological processes.

The relationship of hemorheological blood values and blood velocity of microcirculatory bloodstream in rats` skin vessels

Non-invasive study of blood rheology is relevant, but quite complex issue. When systemic blood viscosity and hematocrit levels deviate, blood flow indicators in different parts of microvasculature change. Purpose of the study – research of blood flow characteristics in skin microcirculatory bloodstream of rats obtained by high-frequency ultrasound Dopplerography (HFUD) with given changes in rheological blood indicators. The studies were carried out on pubescent male Wistar rats. 3 experimental groups were formed. Group 1 (n = 21) “Hemodilution” – viscosity 1.99 ± 0.02 mPa*s, hematocrit 31.48 ± 0.31%. Group 2 (n = 32) “Reference values” – animals with unchanged blood levels – viscosity 2.84 ± 0.03 mPa*s, hematocrit 41.60 ± 0.3%. Group 3 (n = 32) “Erythrocytosis” – viscosity 3.95 ± 0.04 mPa*s, hematocrit 54.56 ± 0.23%. Dynamic blood viscosity in vitro studies were carried out on oscillatory viscometer. In order to evaluate hematocrit level heparinized whole blood was centrifuged in glass capillaries using; hematocrit values were assessed taking into account sedimentation of formed elements column using a hematocrit reader card. Blood flow in skin microcirculatory bloodstream of rats` left thigh area was estimated by HFUD method using Minimax-Doppler-K hardware and software system, with ultrasound transducer (frequency 20 MHz). Statistical analysis showed the models are correct. Blood indicators of the animals in three experimental groups differed statistically and significantly in terms of blood viscosity and hematocrit. Discriminant analysis was used to determine the relations between rheological blood parameters and characteristics of blood velocity in microcirculatory bloodstream which made it possible to identify the most significant characteristics of blood flow that tend to change depending on altered blood composition. These include: mean systolic velocity Vas (p 0.01), mean velocity Vam (p 0.001), mean volume velocity Qam (p 0.001), vascular resistance index RI (p 0.01) and the percentage of blood cells moving in low-speed H' (p = 0.03). The reliability of selected characteristics was checked with one-way analysis of variance; and their significance in determining membership in “Hemodilution”, “Reference values” or “Erythrocytosis” groups according to HFUD data was confirmed. Based on this analysis classification functions were generated for non-invasive dynamic blood viscosity determination according to ultrasound Dopplerography data.

Utilization of thermoplastic resin as foamed asphalt modifier in cold recycled mixtures

The utilization of foamed virgin asphalt in cold recycled mixtures results in insufficient bonding strength between aggregates, leading to rapid deterioration to the recycled asphalt pavement. This ultimately causes inefficient clean production and increased carbon emissions. The foaming performance of thermoplastic resin modified asphalt (TRA) under different foaming conditions was analyzed. Micro-scale chemical and physical tests were utilized to discover the foaming mechanism of TRA. The road performance of cold recycled mixtures with foamed TRA was evaluated through splitting, rutting and fatigue tests. The results showed that the increase in the TRA polar functional group index led to an increase in its surface tension, thus limiting its expansion capacity. However, the increase in the specific heat capacity of TRA indicated that it preserves a low viscosity level essential for its foaming efficacy post-ejection from the foaming machine, thereby enhancing its half-life. Furthermore, the dynamic viscosity of the TRA with an 8% thermoplastic resin dosage exceeded 40000 Pa s at 60 °C, meeting the specification requirements for high viscosity asphalt, while exhibiting a notably lower viscosity of only 120 mPa s at the foaming temperature of 170 °C. The observed low viscosity of the asphalt is anticipated to favorably enhance the formation of a stable foam structure. The mechanical properties and overall road performance of the cold recycled mixture with foamed TRA were significantly enhanced, especially in terms of moisture damage resistance and low-temperature crack resistance. The purpose of this paper is to serve as a valuable reference for investigating the mechanism of modified asphalt foaming and to enhance the efficiency of cold recycled pavement regeneration processes.

Poly(lactide) Upcycling Approach through Transesterification for Stereolithography 3D Printing.

The legislature determines the recycled and waste contents in fabrication processes to ensure more sustainable production. PLA's mechanical recycling and reuse are limited due to the performance decrease caused by thermal or hydrolytic instability. Our concept introduces an upcycling route involving PLA depolymerization using propylene glycol as a reactant, followed by the methacrylation, assuring the liquid systems' curability provided by radical polymerization. PLA-containing curable systems were studied from a rheological and thermomechanical viewpoint. The viscosity levels varied from 33 to 3911 mPa·s at 30 °C, giving a wide capability potential. The best system reached 2240 MPa storage modulus, 164.1 °C glass-transition temperature, and 145.6 °C heat-resistant index, competitive values to commercial systems. The printability was verified for all of the systems. Eventually, our concept led to SLA resin production containing PLA waste content up to 51 wt %.

A dual sensitive fluorescence probe for the simultaneous visualization of hypochlorite and viscosity in living cells and zebrafish

As vital microenvironmental indicators, hypochlorite and viscosity levels can be applied to diagnose diseases. Thus, real time and in situ monitoring of hypochlorite and viscosity has gained increasing attentions. A fluorescence probe named JDK was developed by using a novel acceptor of 2-(2-(5-(dimethylamino)thiophen-2-yl)vinyl)-1,3,3-trimethyl-3H-indol-1-ium fluorophore basing on FRET and TICT system. JDK possessed large Stokes shift, broad emission peak gap, prominent photostability and biocompatibility. JDK could track hypochlorite with rapid response time (within 1 min) and low detection limit (28.5 nM). Meaningfully, JDK was favor to append on mitochondria where physiological processes can be disrupted deriving from the abnormal concentrations of hypochlorite and viscosity. Successfully, JDK could visualize endogenous hypochlorite and viscosity in living cells and zebrafish.

Impact of blood viscosity on hemodynamics of large intracranial aneurysms

BackgroundHemodynamic factors play an important role in the formation and rupture of intracranial aneurysms. Blood viscosity has been recognized as a potential factor influencing the hemodynamics of aneurysms. Computational fluid dynamics (CFD) is one of the main methods to study aneurysm hemodynamics. However, current CFD studies often set the viscosity to a standard value, neglecting the effect of individualized viscosity on hemodynamics. We investigate the impact of blood viscosity on hemodynamics in large intracranial aneurysm (IA) and assess the potential implications for aneurysm growth and rupture risk. MethodsCFD simulations of 8 unruptured large internal carotid artery aneurysms were conducted using pulsatile inlet conditions. For each aneurysm, CFD simulations were performed at 5 different viscosity levels (0.004, 0.006, 0.008, 0.010, and 0.012 Pa·s). Differences in hemodynamic parameters across viscosity levels were compared using paired t-tests, and the correlation between viscosity and hemodynamic parameters was analyzed. ResultsIncreasing blood viscosity leads to significant decrease in blood flow velocity within aneurysms. Time-averaged wall shear stress (WSS) showed significant positive correlation with viscosity, particularly at the aneurysm neck. Oscillatory shear index (OSI) showed general decreasing trend with increased viscosity, while it displayed an irregular pattern in a few cases. ConclusionsVariations in viscosity markedly influence velocity, WSS, and OSI in aneurysms, suggesting a role in modulating aneurysm growth and rupture risk. Incorporating patient-specific viscosity values in CFD simulations is vital for accurate and reliable outcomes.

Centerline shock reflection for supersonic internal flows in the non-Rankine-Hugoniot zone: Overexpanded supersonic microjets

The viscous and rarefaction effects on centerline shock reflection occurring in an overexpanded axisymmetric microjet have been investigated numerically by means of a fully coupled pressure-based shock capturing scheme. Due to the low free-stream Reynolds number, the Navier–Stokes equations were coupled with slip velocity and temperature jump boundary conditions to account for rarefied gas effects in the Knudsen layer. It has been found that pronounced viscosity levels can cause a transition from a three-shock to a two-shock configuration, which is impermissible by inviscid theory. This is the first observation of such phenomena in the case of over-expanded jets. Analysis of the von Neumann and detachment criteria indicates that the transition from Mach reflection to regular reflection is analogous to the dual-solution domain transition for planar shocks. In addition, prediction of the longitudinal curvature of the incident shock has been conducted from a mathematical standpoint.

A FRET/TICT based multifunctional fluorescent probe for the monitoring of SO2 derivatives and viscosity in living cells and real samples

SO2 derivatives and viscosity are important intracellular indicators, which are closely associated with various physiological metabolisms in organisms. The unregulated contents of SO2 derivatives and viscosity in vivo commonly related to some disorders. In this work, probe JFT was developed relying on FRET and TICT mechanisms for the simultaneous detection of SO2 derivatives and viscosity. JFT can rapidly detect viscosity levels with continuously enhanced fluorescence signals at 582 nm basing on the increasing of viscosity. Moreover, JFT was also sensitive to the changes of SO2 derivatives level with a low detection limit (61.5 nM), rapid responding time (with 16 min), excellent selectivity and anti-interference capacity. JFT could detect bisulfite in real water, wine and food samples with high accuracy and recovery rate. Cell imaging indicated that JFT could monitor the endogenous SO2 derivatives and viscosity in mitochondria. Importantly, JFT could recognize the cancer cells basing on the cell imaging difference of JFT in AGS and GES-1 cells.