High Shear Viscosity Research Articles

Correlation of Apo B/A1 ratio with hemodynamics and hearing impairment degree in elderly patients with sudden sensorineural hearing loss

ObjectiveTo investigate the correlation of apolipoprotein B/A1 (Apo B/A1) ratio with hemodynamics and degree of hearing impairment in elderly patients with sudden sensorineural hearing loss (SSNHL). MethodsA total of 82 elderly patients with SSNHL diagnosed and treated in our hospital from July 2019 to September 2022 were retrospectively selected as the research group. The patients were divided into the mild group (22 cases), the moderate group (45 cases), and the severe group (15 cases) according to the degree of hearing impairment. 82 elderly people who underwent physical examination in our hospital during the same period were selected as the control group. The ApoB/A1 ratio and hemodynamic [whole blood low-shear viscosity (LSV), whole blood high-shear viscosity (HSV) and plasma viscosity (PV)] were measured in the two groups. The correlation of ApoB/A1 ratio with hemodynamics and degree of hearing impairment was analyzed. The predictive value of ApoB/A1 ratio and hemodynamics for the severity of SSNHL in elderly patients was analyzed. ResultsCompared with the control group, the ApoB/A1 ratio, and the levels of LSV, HSV and PV were higher in the research group (P < 0.001). The ApoB/A1 ratio and content of LSV, HSV and PV in the moderate group were significantly increased compared with these in the mild group (P < 0.05). Compared with the moderate group, the ApoB/A1 ratio and the levels of LSV, HSV and PV in the severe group were significantly increased (P < 0.05). Pearson correlation analysis showed that ApoB/A1 was positively correlated with LSV, HSV and PV (r = 0.303, 0.312, 0.228, P < 0.01). Logistic regression analysis showed that the ApoB/A1 ratio, LSV, HSV and PV levels were independent risk factors for the degree of hearing impairment in elderly patients with SSNHL (P < 0.05). The area under the curve (AUC) of ApoB/A1, LSV, HSV and PV for predicting the severity of SSNHL in elderly patients was 0.701, 0.817, 0.838, and 0.765, respectively. The AUC of combined prediction was 0.926, the sensitivity was 86.67 %, and the specificity was 90.06 %. The sensitivity and specificity of combined detection were higher than those of single detection. ConclusionThe contents of ApoB/A1, HSV, LSV and PV were significantly increased in elderly patients with SSNHL, and their levels are significantly related to the degree of hearing impairment. The combined detection has high value in evaluating the severity of the disease.

Efficacy and Hemorheology of Ginkgo biloba Extract (EGb 761) in the Treatment of Sudden Sensorineural Hearing Loss: A Retrospective Study.

This study aimed to analyze the therapeutic effect of Ginkgo biloba extract (EGb 761) on sudden sensorineural hearing loss (SSNHL) and its influence on hemorheology. The clinical data of patients diagnosed with SSNHL and admitted to the Wendeng Hospital of Traditional Chinese Orthopedics and Traumatology of Shandong Province from May 2020 to May 2023 were retrospectively analyzed. Based on different clinical treatment protocols, patients were divided into a control group (treated with routine treatment) and an administration group (treated with routine treatment + EGb 761). Both groups underwent drug treatment for 10 days. Subsequently, the hearing threshold, hemorheological parameters (blood high shear viscosity, blood low shear viscosity, plasma viscosity, and platelet aggregation rate) and inflammatory factors and serum levels (C-reactive protein, interleukin-6, tumor necrosis factor-α and soluble vascular cell adhesion molecule-1) of these groups were compared. This study comprised 120 patients, with 66 cases in the control group and 54 cases in the administration group. Following treatment, the total effective rate of the administration group was significantly higher than that of the control group (90.74% vs. 72.73%) (P-value < 0.05). The hearing threshold, hemorheological parameters, inflammatory factors, and serum levels were significantly lower in the administration group than in the control group (P-value < 0.05). Compared with routine treatment, joint EGb 761 in the SSNHL treatment may improve the hearing threshold and hemorheological indexes of patients, inhibit the inflammatory response, and promote the recovery of hearing function. Moreover, no serious adverse reactions are observed, indicating adequate safety.

Study on Soil Selenium-Induced Copper Deficiency in Yudong Black Goats.

Due to the degradation of pasture and strict restrictions on grazing ranges in recent years, copper (Cu) deficiency in Yudong black goats has been occurring, mainly manifested as emaciation, anemia, loss of appetite and lack of spirit. To explore the main causes of Cu deficiency in Yudong black goats, 40 black goats (1 year old, 25.11 ± 0.52 kg) were selected for this experiment; among them, 20 Yudong black goats with Cu deficiency from the experimental pasture were used as the experimental group, and 20 healthy Yudong black goats from the control pasture were used as the control group. In the pre-experiment, the mineral contents of the soil, forage, blood, and liver of black goats in both groups were determined, and in formal experiments, blood hematological, biochemical, antioxidant, and hemorheological parameters were analyzed. An experiment on the treatment of Cu deficiency in black goats was also conducted. This study showed that selenium (Se) levels in the soil, forage, blood, and liver from the experimental group were significantly lower than those from the control group (p < 0.01). The content of sulfur (S) in the forage was considerably higher than that of the control group (p < 0.01). The contents of Cu in the blood and liver from the experimental group were significantly lower than that from the control group (p < 0.01), and the content of S was considerably higher than that from the control group (p < 0.01). The blood hematology of the experimental group was affected, as evidenced by a decrease in hemoglobin, hematocrit value, mean corpuscular volume and mean corpuscular hemoglobin. The immunity and antioxidant capacity of black goats in the experiment group were impaired to varying degrees, with significant decreases in ceruloplasmin, immunoglobulin M, immunoglobulin G, glutathione peroxidase, and superoxide dismutase, and substantial increases in malondialdehyde. In addition, the experimental group showed a decrease in blood viscosity as evidenced by the rise in high shear viscosity, low shear viscosity, erythrocyte rigidity index, erythrocyte aggregation index, and erythrocyte deformation index, and a decrease in plasma viscosity. In the treatment experiment, oral administration of copper sulfate solution was carried out on 10 black goats with Cu deficiency. All the Cu deficiency goats were cured, and the Cu content in their bodies rebounded. In summary, low Se soil caused an increase in S content in the forage, and Yudong black goats feeding on high S forage resulted in a decrease in Cu absorption, which led to a secondary Cu deficiency.

Clinical study on treatment of cervical spondylotic radiculopathy (Qi stagnation and blood stasis syndrome) with Gao's nape needle and Shentong Zhuyu decoction.

Cervical spondylotic radiculopathy is currently one of the common orthopedic diseases, mainly characterized by neck pain, stiffness, limited mobility, and related symptoms of nerve root compression, which seriously troubles people's work and life. Ninety cases of cervical spondylotic radiculopathy (Qi stagnation and blood stasis syndrome) were randomly divided into treatment group and control group, 45 cases in each group. The control group was treated with western medicine (nerve nutrition, pain relief, and circulation improvement drugs), and the treatment group was treated with Gao's nape needle combined with modified Shentong Zhuyu decoction on the basis of the control group. Before and after 2 weeks, TCM syndrome score, TCM curative effect, visual analogue scale score, numbness score, neck disability index score, related serum inflammatory factors (interleukin-10 [IL-10], interleukin-6 [IL-6], tumor necrosis factor-α [TNF-α]), related hemorheological indexes (plasma viscosity, high shear whole blood viscosity, low shear whole blood viscosity level) were used as evaluation indexes to evaluate the effect. After treatment, the total effective rate of the treatment group was 91.11%, which was better than that of the control group (78.78%), and the TCM syndrome scores of the 2 groups were decreased, the treatment group was better than that of the control group, and the differences were statistically significant (P < .05). After treatment, the visual analogue scale score, numbness score, and neck disability index score were decreased in both groups, and the decrease in the treatment group was more significant than that in the control group, and the differences were statistically significant (P < .05). After treatment, the related serum inflammatory factors (IL-10, IL-6, TNF-α) and related hemorheological indexes (plasma viscosity, high-shear whole blood viscosity, low-shear whole blood viscosity) were decreased in both groups, and the decrease in the treatment group was more significant than that in the control group, and the differences were statistically significant (P < .05). The treatment of cervical spondylotic radiculopathy (Qi stagnation and blood stasis syndrome) with Gao's nape needle and modified Shentong Zhuyu decoction can improve the curative effect of traditional Chinese medicine, improve the related discomfort symptoms (neck tenderness, adverse activity, numbness, etc), improve the neck function, reduce IL-10, IL-6, TNF-α, and other related serum inflammatory factors, and improve hemorheological indicators.

Effect of Acoustic Environment in Wards on Postoperative Rehabilitation in Patients with Oral Cancer: A Retrospective Study.

The increase in patient flow, replacement of medical equipment, and variations in surrounding environments induce increasingly serious acoustic environment problems in hospitals. This study aims to provide additional bases for the formulation of subsequent management plans in clinical practice by analyzing the influence of the acoustic environment in wards and the postoperative rehabilitation effect among patients with oral cancer. The medical records of 210 patients with oral cancer undergoing surgical treatment in Jinan Stomatological Hospital from February 2020 to October 2022 were selected for retrospective analysis. Patients with the acoustic environment in wards >55 and ≤55 dB were classified as groups A and B, respectively, according to the acoustic environment in wards. The effects of the acoustic environment in wards on postoperative blood pressure, blood viscosity, and blood glucose fluctuation (BGF) were observed to further analyze their relationship. No significant difference was observed in indices such as preoperative systolic pressure (SP), diastolic pressure (DP), cardiac output (CO), postoperative CO, total cholesterol, and low- and high-density lipoproteins between the two groups (P > 0.05). The SP, DP, whole blood low-shear viscosity (WBLSV), whole blood middle-shear viscosity (WBMSV), whole blood high-shear viscosity (WBHSV), and BGF in group B were significantly lower than group A (P < 0.05). Correlation results showed that the total mean value of the acoustic environment in wards was positively correlated with SP, DP, WBLSV, WBMSV, WBHSV, and BGF (P < 0.05). The high acoustic environment in wards is significantly positively correlated with postoperative blood pressure, blood viscosity, and BGF in patients with oral cancer. The hospital should focus on and strengthen the management of the acoustic environment in wards, providing additional schemes to promote the postoperative recovery of patients with oral cancer.

Relationship between lipoprotein(a) and whole blood reducing viscosity: A cross-sectional study.

Lipoprotein(a) [Lp(a)] has been confirmed as a causal risk factor of atherosclerotic cardiovascular disease, but its role on circulation is not completely clear and is still being explored. Therefore, this study attempts to explore the relationship between Lp(a) and whole blood reducing viscosity (WBRV), to better understand the role of Lp(a) in circulatory and cardiovascular diseases. We retrospectively analyzed the data of consecutive subjects in the physical examination center of the Affiliated Hospital of Ningbo University Medical College from January 2022 to May 2022. Pearson or spearman correlation analysis was used to test the statistical relationship between 2 continuous variables according to whether they are normal; 131 participants were retrospectively enrolled in this study. The low-density lipoprotein concentration was associated with whole blood viscosity at low-shear (R = 0.220, P = .012), middle-shear (R = 0.226, P = .01), and high-shear viscosity (R = 0.212, P = .015), as well as plasma viscosity (RS = 0.207, P = .018). Lp(a) was not associated with whole blood viscosity at low, middle, and high shear rates, but was associated with WBRV at low shear (RS = 0.204, P = .019) and middle shear rates (RS = 0.197, P = .024). Lp(a) is associated with high WBRV, which may impart more insights into the role of Lp(a) in cardiovascular disease.

Using Computation Fluid Dynamics to Determine Oil Droplet Breakup Parameters during Emulsion Atomization with Pressure Swirl Nozzles

A wide range of commercial powdered products are manufactured by spray drying emulsions. Some product properties are dependent on the oil droplet size, which can be affected by fluid mechanics inside the spray nozzle. However, most of the key flow parameters inside the nozzles are difficult to measure experimentally, and theoretical estimations present deviations at high shear rates and viscosities. Therefore, the purpose of this study was to develop a computational model that could represent the multiphase flow in pressure swirl nozzles and could determine the deformation stresses and residence times that oil droplets experience. The multiphase flow was modelled using the Volume-of-Fluid method under a laminar regime. The model was validated with experimental data using the operating conditions and the spray angle. The numerically calculated shear stresses were found to provide a better prediction of the final oil droplet size than previous theoretical estimations. A two-step breakup mechanism inside of the nozzle was also proposed. Additionally, some of the assumptions used in the theoretical estimations could not be confirmed for the nozzles investigated: No complete air core developed inside of the nozzle during atomization, and the shear stress at the nozzle outlet is not the only stress that can affect oil droplet size. Elongation stresses cannot be neglected in all cases.

Effect of sitagliptin combined with Yiqi yangyin huoxue decoction on clinical efficacy and hemorheology in early diabetic nephropathy.

Early diabetic nephropathy (DN) is a complication of diabetes mellitus. It mainly affects kidney microvessels and glomerular function, and its timely and effective treatment is critical for early DN. However, the effects of treatments comprising simple Western medicine are not optimal. With the promotion and implementation of integrated Chinese and western medicine treatments, remarkable results have been achieved for many diseases. To this end, we explored the clinical efficacy of integrated traditional Chinese and western medicines for the treatment of early DN. To investigate the effect of sitagliptin tablets combined with Yiqi yangyin huoxue decoction on clinical efficacy and hemorheology in patients with early DN. Through a retrospective analysis, 123 patients with early DN were admitted to the endocrinology clinic of the Changzhou NO. 7 People's Hospital from January 2021 to October 2022 and were selected as study subjects. After rigorous screening, 100 patients with early DN were enrolled. The control group (CG, n = 50) and the observation group (OG, n = 50) were divided according to the treatment method. The CG were treated with sitagliptin, and the OG were treated with sitagliptin plus the Yiqi yangyin huoxue decoction. Both groups were treated for 3 mo. For both groups, the baseline data and clinical efficacy were compared, and changes in blood glucose levels, lipid levels, renal function, and hematological indicators before (T0) and after (T1) treatment were assessed. The total effective rate for the OG was 94.00% and that of the CG was 80.00% (P < 0.05). After treatment (T1), the levels of fasting blood glucose, 2 h postprandial glucose, total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol in OG patients were obviously lower than those in the CG (P < 0.05), and cystatin C, homocysteine, urinary microalbumin, and blood creatinine values in OG patients were also obviously lower than those in the CG (P < 0.05); erythrocyte deposition, plasma viscosity, whole blood high shear viscosity, and whole blood low shear viscosity were markedly lower in OG patients than in the CG (P < 0.05). Sitagliptin combined with Yiqi yangyin huoxue decoction has a remarkable effect when used to treat patients with early DN. Further, it is helpful in improving hemorheological indices and controlling disease progression.

Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps.

From a circular economy perspective, one-pot strategies for the isolation of cellulose nanomaterials at a high yield and with multifunctional properties are attractive. Here, the effects of lignin content (bleached vs unbleached softwood kraft pulp) and sulfuric acid concentration on the properties of crystalline lignocellulose isolates and their films are explored. Hydrolysis at 58 wt % sulfuric acid resulted in both cellulose nanocrystals (CNCs) and microcrystalline cellulose at a relatively high yield (>55%), whereas hydrolysis at 64 wt % gave CNCs at a lower yield (<20%). CNCs from 58 wt % hydrolysis were more polydisperse and had a higher average aspect ratio (1.5-2×), a lower surface charge (2×), and a higher shear viscosity (100-1000×). Hydrolysis of unbleached pulp additionally yielded spherical nanoparticles (NPs) that were <50 nm in diameter and identified as lignin by nanoscale Fourier transform infrared spectroscopy and IR imaging. Chiral nematic self-organization was observed in films from CNCs isolated at 64 wt % but not from the more heterogeneous CNC qualities produced at 58 wt %. All films degraded to some extent under simulated sunlight trials, but these effects were less pronounced in lignin-NP-containing films, suggesting a protective feature, but the hemicellulose content and CNC crystallinity may be implicated as well. Finally, heterogeneous CNC compositions obtained at a high yield and with improved resource efficiency are suggested for specific nanocellulose uses, for instance, as thickeners or reinforcing fillers, representing a step toward the development of application-tailored CNC grades.

Association of blood viscosity and device-free days among hospitalized patients with COVID-19

BackgroundIncreased estimated whole blood viscosity (eWBV) predicts higher mortality in patients hospitalized for coronavirus disease 2019 (COVID-19). This study assesses whether eWBV is an early predictor of non-fatal outcomes among patients hospitalized for acute COVID-19 infection.MethodsThis retrospective cohort study included 9278 hospitalized COVID-19 patients diagnosed within 48 h of admission between February 27, 2020 to November 20, 2021 within the Mount Sinai Health System in New York City. Patients with missing values for major covariates, discharge information, and those who failed to meet the criteria for the non-Newtonian blood model were excluded. 5621 participants were included in the main analysis. Additional analyses were performed separately for 4352 participants who had measurements of white blood cell count, C-reactive protein and D-dimer. Participants were divided into quartiles based on estimated high-shear blood viscosity (eHSBV) and estimated low-shear blood viscosity (eLSBV). Blood viscosity was calculated using the Walburn–Schneck model. The primary outcome was evaluated as an ordinal scale indicating the number of days free of respiratory organ support through day 21, and those who died in-hospital were assigned a value of -1. Multivariate cumulative logistic regression was conducted to evaluate the association between quartiles of eWBV and events.ResultsAmong 5621 participants, 3459 (61.5%) were male with mean age of 63.2 (SD 17.1) years. The linear modeling yielded an adjusted odds ratio (aOR) of 0.68 (95% CI 0.59–0.79, p value < 0.001) per 1 centipoise increase in eHSBV.ConclusionsAmong hospitalized patients with COVID-19, elevated eHSBV and eLSBV at presentation were associated with an increased need for respiratory organ support at 21 days. These findings are highly relevant, as they demonstrate the utility of eWBV in identifying hospitalized patients with acute COVID-19 infection at increased risk for non-fatal outcomes in early stages of the disease.

A holistic view on the role of egg yolk in Old Masters’ oil paints

Old Masters like Botticelli used paints containing mixtures of oils and proteins, but “how” and “why” this was done is still not understood. Here, egg yolk is used in combination with two pigments to evaluate how different repartition of proteinaceous binder can be used to control the flow behavior as well as drying kinetics and chemistry of oil paints. Stiff paints enabling pronounced impasto can be achieved, but paint stiffening due to undesired uptake of humidity from the environment can also be suppressed, depending on proteinaceous binder distribution and colloidal paint microstructure. Brushability at high pigment loading is improved via reduction of high shear viscosity and wrinkling can be suppressed adjusting a high yield stress. Egg acts as antioxidant, slowing down the onset of curing, and promoting the formation of cross-linked networks less prone to oxidative degradation compared to oil alone, which might improve the preservation of invaluable artworks.

Edaravone combined with Shuxuening versus edaravone alone in the treatment of acute cerebral infarction: A systematic review and meta-analysis.

Shuxuening injection (SXN) is a traditional Chinese medicine used in the treatment of cardiovascular diseases. Whether it can provide better outcomes when combined with edaravone injection (ERI) for the treatment of acute cerebral infarction is not well determined. Therefore, we evaluated the efficacy of ERI combined with SXN versus that of ERI alone in patients with acute cerebral infarction. PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang electronic databases were searched up to July 2022. Randomized controlled trials comparing the outcomes of efficacy rate, neurologic impairment, inflammatory factors, and hemorheology were included. Odds ratio or standard mean difference (SMD) with corresponding 95% confidence intervals (CIs) were used to present the overall estimates. The quality of the included trials was evaluated by the Cochrane risk of bias tool. The study was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses. Seventeen randomized controlled trials were included consisting of 1607 patients. Compared to ERI alone, treatment with ERI plus SXN had a greater effective rate than ER alone (odds ratio = 3.94; 95% CI: 2.85, 5.44; I2 = 0%, P < .00001), a lower National Institute of Health Stroke Scale (SMD= -1.39; 95% CI: -1.73, -1.05; I2 = 71%, P < .00001), lower neural function defect score (SMD= -0.75; 95% CI: -1.06,-0.43; I2 = 67%, P < .00001), and lower level of neuron-specific enolase (SMD= -2.10; 95% CI: -2.85, -1.35; I2 = 85%, P < .00001). ERI plus SXN treatment provided significant improvements in whole blood high shear viscosity (SMD = -0.87; 95% CI: -1.17, -0.57; I2 = 0%, P < .00001), and whole blood low shear viscosity (SMD = -1.50; 95% CI: -1.65, -1.36; I2 = 0%, P < .00001) compared to ERI alone. ERI plus SXN showed better efficacy than ERI alone for patients with acute cerebral infarction. Our study provides evidence supporting the application of ERI plus SXN for acute cerebral infarction.

Impact of Topological Parameters on Melt Rheological Properties and Foamability of PS POM-POMs

Rheological properties highly impact the foaming behavior of polymers, as a high melt strength and low shear viscosity support cell expansion by reducing cell coalescence and rupture. Since rheological properties originate from molecular topology, topology is consequently a governing parameter for foaming. We synthesized well-defined polystyrene (PS) POM-POM-shaped model systems to study the impact of the topology-originated melt rheological parameters on the physical foaming behavior within purely amorphous polymers without any crystallization effects. Therefore, we systematically varied the topological parameters of the POM-POM topology, i.e., the number of arms q, the arm length Mw,a, and the backbone length Mw,b. We investigated the melt rheological properties of the samples concerning their zero-shear viscosity and elongational strain hardening and correlated their resulting foam structure. Within the sample series, η0 can be reduced by up to 104, compared to linear PS with the same total molecular weight, whereas the maximum achieved strain hardening factor is SHF = 141 at T = 160 °C. The foaming experiments revealed that the mean cell size D and the volume expansion VER can be precisely controlled via molecular topology. By controlling the topological parameters, it was possible to increase VER from VER = 2.0 to 15.6, whereas D varied between D = 1.3 and 17.2 μm within 100–150 °C under a pressure of 500 bar. In comparison, the VER of linear PS increased from VER = 2.6 to 5.4, while D increased from D = 2.3 to 4.8 μm. Moreover, the influence of topology is more pronounced at higher temperatures, indicating that the molecular relaxation times and the applied shear rates need to be related. Hence, it is possible to tailor the cellular structure to a specific application by considering and controlling the polymer topology.

Effect of plan-do-check-active method combined with air pressure wave therapy on the prevention of deep venous thrombosis in critically ill patients in neurosurgery

Deep vein thrombosis (DVT) is prone to occur in the recovery of critically ill neurosurgical patients, increasing economic and psychological pressure, and even endangering life. Plan-Do-Check-Action (PDCA) cycle is a kind of quality management cycle procedure, which can help DVT treatment correctly understand the cause of disease and take effective preventive and nursing measures. The air wave pressure therapy instrument takes pressure therapy as the core, forming circulating pressure on limbs and tissues, promoting the flow of blood and lymph, improving the effect of microcirculation, accelerating the return of limb tissue fluid, and preventing thrombosis and limb edema. A total of 98 critical neurosurgery patients were selected as the study subjects. On the basis of PDCA circulation treatment, the patients were treated with air pressure wave for 30 minutes/time, twice/day and 14 days. Before and after treatment, the indexes of coagulation function, hemorheology (plasma viscosity, whole blood high shear viscosity and whole blood low shear viscosity), lower limb circumference (15 cm above and below the patella) and Barthel index (BI) scores were observed and recorded. DVT was observed by vascular Doppler ultrasound before and after treatment, and the incidence was calculated. The prothrombin time (18.09 s) and thrombin time (17.66 s) after treatment were higher than those before treatment (12.98 s, 130.7 s), and fibrinogen decreased (4.21 vs. 3.31 g/L). The hemorheological indexes of the patients after treatment were plasma viscosity (1.49 mPa/s, 10.8 mPa/s), whole blood high shear viscosity (6.34 mPa/s, 4.47 mPa/s), whole blood low shear viscosity (9.89 mPa/s, 6.32 mPa/s), circumference at 15 cm below the patella (52.29 cm, 45.23 cm), and circumference at 15 cm above the patella (36.17 cm, 31.38 cm). The BI score showed that the number of patients with severe dependence on grade A (46/15) and moderate dependence on grade B (50/14) decreased after treatment, and the average BI score of patients with combined treatment increased (43.87 and 79.86). After treatment, the number of patients with DVT (20/4) and the incidence of DVT (20.40816327%, 4.081632653%) decreased significantly (P<0.05). PDCA circulation combined with barometric wave therapy can significantly improve DVT in critical neurosurgical patients.

Melt processing behaviour and structure development in recycled PP blends with recycled PET

Commercially available recycled polypropylene (R-PP) and recycled bottle grade polyethylene terephthalate (R-PET) were melt compounded in different proportions of R-PET in twin screw extruder at temperatures used typically for PP processing. The melt flow behaviour was investigated for these blends using capillary rheometer at different temperatures viz. 230, 250, 260°C. The crystallization and structure development was studied using DSC and XRD. The melt viscosity (η) of these blends followed the usual non-Newtonian behaviour with decrease of η with high shear rate (γ′) and saturation at low shear rate. Most noteworthy finding was that the low shear viscosity at melt temperatures of 230 and 250 showed a peak with increase of R-PET content while at 260°C there was uniform decrease in the viscosity with addition of R-PET. The high shear viscosity also showed similar trend but with less pronounced changes. This was attributed to the cross over of domain shape from spherical to ellipsoidal and finally fibrous shape according to Utracki model. At the melt compounding/processing temperature of 230°C, the R-PET phase was in semi solid state and hence it formed fibrous morphology in the PP melt which was confirmed by SEM analysis. The most interesting finding was that crystallization of both the component polymers was affected due to the presence of the other. R-PP showed nucleation effect in presence of R-PET with the shift in Tc from 118°C to higher temperature side (123°C). Even R-PET exhibited shift in the Tc from 178°C to 201°C in presence of R-PP. These results are discussed in terms of nucleation and slow heat dissipation for PET domain in PP melt together with shear induced crystallization. These structural modifications in the R-PP/R-PET blends led to improvement in properties at certain compositions processed under certain conditions.

Microstructure, rheological and water mobility behaviour of plant-based protein isolates (pea and quinoa) and locust bean gum mixtures

This work reports the impact of locust bean gum (LBG) in the continuous phase of plant-based proteins, i.e. quinoa protein (QPI) and pea protein isolates (PPI). Experimental measurements such as confocal microscopy, rheological analysis and water mobility via nuclear magnetic resonance (nmr) spin-spin relaxation time (T2) were carried out. The influence of LBG on the rheological properties of QPI and PPI is consistent with an exchange-based nmr interpretation of T2 for biopolymer and water. Addition of LBG increased the viscoelastic properties (storage and loss modulus) and shear viscosities of the mixtures. LBG interacted with both plant proteins, resulting in the formation of more dense protein networks and protein coacervates. A stronger interaction between the PPI and LBG was observed, resulting in higher shear viscosities with lower water mobility as compared to QPI:LBG formulations. Results indicated that the interaction between the protein and polysaccharide played a significant role in the microstructure, its rheological properties and consequently water mobility.

Rheology of emulsions with polymer solutions as the continuous phase

We investigate the effect of the addition of polymers on the flow properties of emulsions. Surfactant-stabilised 80 v% oil-in-water emulsions, exhibiting a yield stress, with either xanthan gum (a stiff, rodlike polymer) or polyethylene oxide (PEO, a flexible, elastic polymer) in the continuous phase (concentrations between 0.005 wt% and 0.5 wt%) are prepared and investigated using shear rheology and confocal microscopy. The flow properties of the emulsions are very robust, and only at high concentrations of polymer (≥ 0.2 wt%), significant changes in the flow properties are observed. In the case of xanthan gum, higher shear stresses are measured. For high concentrations the yield stress is masked by the high zero shear viscosity and shear thinning behaviour of the xanthan gum giving rise to an apparent second power law regime. In the case of PEO, an increase in the shear thinning exponent is observed, together with a decrease in the yield stress. The interaction of PEO with the surfactant SDS (sodium dodecyl sulfate) at higher PEO concentrations strongly affects the emulsion rheology, perhaps by reducing the friction coefficient between the oil droplets.

Determination of Mixing and Compaction Temperatures for the Rubberized Asphalt Binders Based on Shear Rate Dependent Viscosity

Despite the numerous advantages of using modified asphalt binders, there are a number of challenges associated with their use. One of these challenges is related with specifying the temperatures at which modified asphalt binders should be mixed and compacted. The Equiviscous method aims to calculate the Mixing and Compaction Temperatures (MCTs) of the unmodified binder. Nevertheless, the implementation of this method for modified asphalt binder results in very high MCTs, which may not be appropriate during the asphalt mixes construction. This paper investigates two alternative methods for the modified binder with Crumb Rubber (CR), referred to as the High Shear Rate (HSR) viscosity and Zero Shear Viscosity (ZSV) methods. Besides, the MCTs obtained from these methods are compared to the ones obtained using the Equiviscous method. For this purpose, one type of asphalt binder modified with three percent of CR has been used. The results have shown that the application of the ZSV method has resulted in more reasonable MCTs for the rubberized binder, which have been from 30 to 50 °C lower than the ones obtained using the Equiviscous method.

Effects of dispersing media on the shear and extensional rheology of xanthan gum and guar gum-based thickeners used for dysphagia management

Thickening powders are regularly used in various drinks for the effective management of dysphagia and for the improved quality of life of these patients. Rheology of these thickened liquids can change significantly depending on the dispersing media that may lead to some adverse effects. Therefore, the effects of dispersing media, i.e., water, apple juice and low-fat milk, on shear and extensional rheology of thickened liquids prepared with xanthan gum or guar gum-based thickening powders were investigated in this study. Shear rheological results revealed a power law concentration dependence of the relative zero shear viscosity ( η r , 0 ∝ c n ) for both thickening powders in all dispersing media, i.e., n = 3.41–4.26 for xanthan gum-based and n = 4.55–5.42 for guar gum-based. For a given thickening powder concentration, the zero shear viscosity was mainly affected by the dispersing media, whereas there was no marked effect on high shear viscosity, especially at shear rate 50 s −1 that is a characteristic value traditionally assumed for oral processing. The flow behaviour of all samples could be described effectively by the modified Carreau-Yasuda model, thus, making it more convenient to compare the material parameters among different samples. Additionally, these dispersing media showed drastic effect on extensional rheological characteristics of the thickened samples, particularly on the filament life span and extensional viscosity. For xanthan gum-based powder, the values of both parameters were decreased at least 2-fold when dissolved in apple juice or milk, signifying weakening extensional property of these thickened beverages compared to thickened water. However, for guar gum-based thickener, enhanced extensional properties were obtained when dissolved in milk, whereas partial hydrolysis may occur in apple juice, leading to inferior extensional property compared to that of water. These differences are largely ascribed to molecular characteristics of the active polysaccharides in these thickening powders. Overall, these results provide new insights into the shear and extensional rheology of food thickeners in various dispersing media that can be used to assist in treating individual patients with dysphagia. • Rheology of thickened liquids were affected by different dispersing media. • For all thickened liquids, zero shear viscosity was mainly affected by different dispersing media. • No marked effect on high shear viscosity, especially at shear rate 50 s -1 representing oral processing, was observed. • Extensional properties were for xanthan gum-based thickened apple juice and milk compared to water. • Enhanced extensional properties were obtained for guar gum-based thickened milk.

Influence of thickeners (microfibrillated cellulose, starch, xanthan gum) on rheological, tribological and sensory properties of low-fat mayonnaises

Microfibrillated cellulose (MFC) is obtained by high-shear treatment of cellulose. MFC is suitable for use as clean-label, low-calorie thickener in semi-solid foods such as mayonnaises due to its high water holding capacity. The aim of this study was to determine the effect of type and concentration of thickener on rheological, tribological and sensory properties of low-fat mayonnaises. Low-fat mayonnaises were prepared with four types of thickeners (MFC, chemically modified starch, native waxy corn starch, xanthan gum) at three concentrations. Higher biopolymer concentrations resulted in increased shear viscosities, G′ and G″, yield stress and enhanced lubrication (i.e. lower friction coefficients). Mayonnaises with modified starch and xanthan gum generally had higher shear viscosity and yield stress compared to mayonnaises with comparable concentrations of MFC and waxy corn starch. MFC-thickened mayonnaises had highest G’, G” and boundary friction coefficients. Sensory properties of mayonnaises were determined using the Rate-All-That-Apply (RATA) method (n = 80). Addition of xanthan gum induced high sliminess and pulpiness, and low melting, creaminess and smoothness. Sensory properties of mayonnaises with MFC were generally similar to those with modified and waxy corn starch, despite differences in appearance (increased yellowness and slightly lower glossiness). Multiple Factor Analysis revealed that more shear-thinning mayonnaises were perceived as slimy. Boundary friction was negatively correlated with stickiness, while friction at the start of the hydrodynamic regime was positively correlated with melting sensations. We conclude that microfibrillated cellulose can be used as a thickener in low-fat mayonnaise as an alternative to commercially used chemically modified starch without considerably affecting its sensory texture properties.