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1.
MAbs ; 15(1): 2169440, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36705325

RESUMO

Solutions of monoclonal antibodies (mAbs) can show increased viscosity at high concentration, which can be a disadvantage during protein purification, filling, and administration. The viscosity is determined by protein-protein-interactions, which are influenced by the antibody's sequence as well as solution conditions, like pH, buffer type, or the presence of salts and other excipients. To predict viscosity, experimental parameters, like the diffusion interaction parameter (kD), or computational tools harnessing information derived from primary sequence, are often used, but a reliable predictive tool is still missing. We present a modeling approach employing artificial neural networks (ANNs) using experimental factors combined with simulation-derived parameters plus viscosity data from 27 highly concentrated (180 mg/mL) mAbs. These ANNs can be used to predict if mAbs exhibit problematic viscosity at distinct concentrations or to model viscosity-concentration-curves.


Assuntos
Anticorpos Monoclonais , Sais , Viscosidade , Simulação por Computador , Redes Neurais de Computação , Soluções
2.
Talanta ; 255: 124243, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36630789

RESUMO

In the work limitations of deep eutectic solvents in the flow-based analysis are discussed. Deep eutectic solvents based on terpenes and fatty acids with low viscosity were studied as extraction solvents for liquid-liquid microextraction into a lab-in-syringe system for the first time. As a result an automated deep eutectic solvent-based microextraction approach was proposed. The procedure involved aspiration of deep eutectic solvent (based on terpene and fatty acid) and aqueous sample solution followed by phases mixing by a magnetic stirrer inside a syringe of flow system. After phase separation the extract phase was transferred from the syringe into a vial followed by analysis by a high-performance liquid chromatography with diode-array detection. The determination of Sudan I, Sudan II and Sudan III in chili-based sauces was considered as an analytical task. The mass-transfer intensification performed by the magnetic stirring inside the syringe allowed to perform fast (2 min) and efficient (extraction recoveries 87-95%) extraction. The limits of detection, calculated from a blank test based on 3σ, were from 0.003 to 0.005 mg kg-1, RSD was <9%. The microextraction procedure did not involve the use of hazardous organic solvents, only 100 µL of natural deep eutectic solvent was required for dyes preconcentration.


Assuntos
Microextração em Fase Líquida , Microextração em Fase Líquida/métodos , Solventes Eutéticos Profundos , Seringas , Corantes/análise , Viscosidade , Solventes/química , Ácidos Graxos/análise , Automação , Limite de Detecção
3.
Anal Chim Acta ; 1242: 340813, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36657896

RESUMO

Viscosity is an important component of cell microenvironment, and abnormal mitochondrial viscosity is associated with many diseases such as tumor and fatty liver. Herein, a near-infrared fluorescence probe (QX-V) based on quinoline-xanthene dye for detecting viscosity is constructed. In high viscosity medium, the free rotation of single bond is inhibited and the fluorescence is released. The probe shows high sensitivity together with good selectivity. Notably, QX-V has a long excitation wavelength (710 nm) and emission wavelength (786 nm). At the same time, the probe is a positively charged molecule that can target mitochondria. QX-V can not only distinguish cancer cells from normal cells, but also make a distinction between normal cells and fatty hepatocytes. In addition, QX-V is used to image viscosity abnormality in tumor-bearing mice. The probe also has a good ability to image viscosity abnormality caused by liver injury in fatty-liver mice.


Assuntos
Fígado Gorduroso , Neoplasias , Humanos , Camundongos , Animais , Corantes Fluorescentes/química , Viscosidade , Imagem Óptica/métodos , Mitocôndrias/química , Células HeLa , Fígado Gorduroso/patologia , Neoplasias/diagnóstico por imagem , Neoplasias/patologia
4.
Sci Rep ; 13(1): 422, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624137

RESUMO

Cytoplasmic viscosity is a crucial parameter in determining rates of diffusion-limited reactions. Changes in viscosity are associated with several diseases, whilst nuclear viscosity determines gene integrity, regulation and expression. Yet how drugs including DNA-damaging agents affect viscosity is unknown. We demonstrate the use of a platinum complex, Pt[L]Cl, that localizes efficiently mostly in the nucleus as a probe for nuclear viscosity. The phosphorescence lifetime of Pt[L]Cl is sensitive to viscosity and provides an excellent tool to investigate the impact of DNA damage. We show using Fluorescence Lifetime Imaging (FLIM) that the lifetime of both green and red fluorescent proteins (FP) are also sensitive to changes in cellular viscosity and refractive index. However, Pt[L]Cl proved to be a more sensitive viscosity probe, by virtue of microsecond phosphorescence lifetime versus nanosecond fluorescence lifetime of FP, hence greater sensitivity to bimolecular reactions. DNA damage was inflicted by either a two-photon excitation, one-photon excitation microbeam and X-rays. DNA damage of live cells causes significant increase in the lifetime of either Pt[L]Cl (HeLa cells, 12.5-14.1 µs) or intracellularly expressed mCherry (HEK293 cells, 1.54-1.67 ns), but a decrease in fluorescence lifetime of GFP from 2.65 to 2.29 ns (in V15B cells). These values represent a viscosity change from 8.59 to 20.56 cP as well as significant changes in the refractive index (RI), according to independent calibration. Interestingly DNA damage localized to a submicron region following a laser microbeam induction showed a whole cell viscosity change, with those in the nucleus being greater than the cytoplasm. We also found evidence of a by-stander effect, whereby adjacent un-irradiated cells also showed nuclear viscosity change. Finally, an increase in viscosity following DNA damage was also observed in bacterial cells with an over-expressed mNeonGreen FP, evidenced by the change in its lifetime from 2.8 to 2.4 ns.


Assuntos
Dano ao DNA , Refratometria , Humanos , Células HeLa , Viscosidade , Células HEK293 , Corantes Fluorescentes
5.
Chem Commun (Camb) ; 59(8): 1030-1033, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36601999

RESUMO

The viscosity of the cell microenvironment is a parameter that affects cell physiological processes. A fluorescent probe X-V was designed to detect the viscosity changes of a hepatic ischemia-reperfusion injury (HIRI) cell model with high selectivity and sensitivity. The fluorescence emission wavelength is 615 nm and the Stokes shift can be up to 125 nm, which can be used not only for intracellular viscosity changes stimulated by different drugs but also for the detection of cell viscosity changes in the HIRI cell model. Probe X-V provides a useful tool to study the relationship between mitochondrial viscosity and related diseases.


Assuntos
Corantes Fluorescentes , Traumatismo por Reperfusão , Humanos , Viscosidade , Mitocôndrias , Microscopia de Fluorescência/métodos , Imagem Óptica/métodos , Células HeLa
6.
Molecules ; 28(2)2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36677556

RESUMO

A study was conducted on selected physicochemical properties of blackberry jelly-like desserts (kissel) prepared from physically modified starches (with various degrees of inhibition) and chemically modified starches (with various degrees of cross-linking). The desserts were conventionally sweetened with saccharose (S) or, as a dietary alternative, xylitol (X). The characteristics of changes in the viscosity of the kissels as a function of temperature and time were determined. It was noted that regardless of the sweetener used, the viscosity of the kissels increased with the decreasing degree of inhibition (high < medium < low). Regardless of the kind of modification of the starch used for the preparation of the kissels and of the kind of sweetener, thixotropy was observed. Desserts prepared from inhibited starch with xylitol (CL + X) were characterised by the biggest range of their hysteresis loop. Progressing retrogradation was noted with the decrease in the temperature of the experiment (+20 °C and +4 °C). After 7 days of storage, kissels sweetened with saccharose were characterised by a low transparency, which may indicate retarded retrogradation; however, on day 28, the transparency significantly increased, exceeding the values of transmittance for samples sweetened with xylitol. The tendency towards syneresis was tested at +4 °C and -22 °C. The substitution of saccharose with xylitol only caused a slight modification of viscosity. Regardless of the sweetener used and of the level of starch inhibition, lower ranges of the hysteresis loop were noted (apart from CL + X) than in the case of kissels obtained from chemically modified starches. Distinctly lower values of kissel "aging" indices were noted in the case of samples obtained from inhibited starches, and their colour did not significantly differ in relation to the dessert prepared from native starch.


Assuntos
Rubus , Amido , Amido/química , Zea mays/química , Edulcorantes , Xilitol , Excipientes , Viscosidade , Sacarose
7.
Molecules ; 28(2)2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36677758

RESUMO

The quality standards for the export of chestnuts generate large quantities of rejected fruits, which require novel processing technologies for their safe industrial utilization. This study aimed to investigate the impact of high-pressure processing (HPP) and hydrothermal treatments (HT) on the physicochemical properties of rejected chestnut starch. Chestnuts were treated by HPP at 400, 500, and 600 MPa for 5 min and HT at 50 °C for 45 min. In general, all HPP treatments did not induce starch gelatinization, and their granules preserved the integrity and Maltese-cross. Moreover, starch granules' size and resistant starch content increased with the intensity of pressure. Native and HT chestnut starches were the most susceptible to digestion. HPP treatments did not affect the C-type crystalline pattern of native starch, but the crystalline region was gradually modified to become amorphous. HPP-600 MPa treated starch showed modified pasting properties and exhibited the highest values of peak viscosity. This study demonstrates for the first time that after HPP-600 MPa treatment, a novel chestnut starch gel structure is obtained. Moreover, HPP treatments could increase the slow-digesting starch, which benefits the development of healthier products. HPP can be considered an interesting technology to obtain added-value starch from rejected chestnut fruits.


Assuntos
Amilose , Amido , Amido/química , Amilose/química , Viscosidade , Nozes/química , Amido Resistente/análise
8.
J Chem Phys ; 158(3): 031101, 2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36681652

RESUMO

Spectral line shape models can successfully reproduce experimental Rayleigh-Brillouin spectra, but they need knowledge about the bulk viscosity ηb. Light scattering involves GHz frequencies, but since ηb is only documented at low frequencies, ηb is usually left as a free parameter, which is determined by a fit of the model to an experimental spectrum. The question is whether models work so well because of this freedom. Moreover, for light scattering in air, spectral models view "air" as an effective molecule. We critically evaluate the use of ηb as a fit parameter by comparing ηb obtained from fits of the Tenti S6 model to the result of Direct Simulation Monte Carlo (DSMC) for a mixture of Nitrogen and Oxygen. These simulations are used to compute light scattering spectra, which are then compared to experiments. The DSMC simulation parameters are cross-checked with a molecular dynamics simulation based on intermolecular potentials. At large values of the uniformity parameter y, y ≈ 4, where the Brillouin contribution to spectra is large, fitted ηb are 20% larger than the ones from DSMC, while the quality of the simulated spectra is comparable to that of the Tenti S6 line shape model. At smaller y, the difference between fitted and simulated ηb can be as large as 100%. We hypothesize the breakdown of the bulk viscosity concept to be the cause of this fallacy.


Assuntos
Luz , Simulação de Dinâmica Molecular , Viscosidade , Nitrogênio , Oxigênio
9.
Sci Rep ; 13(1): 1299, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36690827

RESUMO

Viscous dissipation causes significant energy losses in fluid flows; in ducts, laminar flows provide the minimum resistance to the motion, whereas turbulence substantially increases the friction at the wall and the consequent energy requirements for pumping. Great effort is currently being devoted to find new strategies to reduce the energy losses induced by turbulence. Here we propose a simple and novel drag-reduction technique which achieves substantial energy savings in internal flows. Our approach consists in driving the flow with a temporally intermittent pumping, unlike the common practice of a constant pumping. We alternate "pump on" phases where the flow accelerates, and "pump off" phases where the flow decays freely. The flow cyclically enters a quasi-laminar state during the acceleration, and transitions to a more classic turbulent state during the deceleration. Our numerical results demonstrate that important energy savings can be achieved by simply modulating the power injection into the system over time. The physical understanding of this process can help the industry in reducing the waste of energy, creating economical benefits and preserving the environment by reducing harmful emissions.


Assuntos
Movimento (Física) , Viscosidade
10.
Carbohydr Polym ; 304: 120496, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36641164

RESUMO

Galactomannan (GM) has been widely applied in food and other fields due to its appealing physicochemical properties. In this work, considering the changes in structural and physicochemical properties of Sophora japonica f. pendula (SJ-GM) with very high mannose to galactose (M/G) ratio in the late deposition stage, extensive exploration is conducted. The core of structural change is the change of M/G ratio (4.94-5.68), which is caused by the loss of galactose side residues modulated by α-d-galactosidase during seed maturation. Afterwards, the more compact conformation, the higher molecular weight, the increased hydrophobicity, and the greater solution viscosity of SJ-GM can be caused. Notably, the gel strength of SJ-GM with the highest M/G surpasses other GMs, including fenugreek gum (M/G = 1.20), guar gum (M/G = 1.80), Gleditsia microphylla gum (M/G = 2.77), and LBG (M/G = 4.00). Finally, SJ-GM is proven to be an attractive alternative to other GMs.


Assuntos
Galactose , Sophora japonica , Galactose/química , Mananas/química , Galactanos , Gomas Vegetais/química , Peso Molecular , Viscosidade
11.
Food Res Int ; 163: 112132, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36596093

RESUMO

The demand of meat analogues (MAs) is consistently increasing. The protein materials for MAs are primarily soy, pea, and wheat protein which can not completely meet the growing demand. Hence, this study is focused on the preparation of MAs with up to 50 % yeast protein (YP) instead of pea protein isolate (PPI). In the present study, 0 %, 10 %, 30 %, and 50 % YP powder in dry matter basis were combined with PPI; then the mixtures were used to prepare MAs with fibrous structures using high-moisture extrusion (55 % moisture). The involvement of YP significantly enhanced the hardness of MAs (P < 0.05). The optical and microstructural images illustrated that when YP ratio reached 30 %, obvious fibrous structures still were observed in MAs. Furthermore, MAs containing YP became whiter, which is conducive to reprocessing. With an increase in YP, the bound water content, sheet structures, and exposure of tryptophan residues in MAs increased, whereas the free water content, ß-turn, and random coil structures decreased. Analysis of thermal and rheological behaviors indicated that YP lowered the denaturation temperature of MAs and the viscosity of protein dispersions, which was related to the formation of protein aggregates. Overall, YP can be used to prepare MAs and regulate the fibrous structure in MAs by acting on protein conformations.


Assuntos
Proteínas de Ervilha , Saccharomyces cerevisiae , Carne , Água/química , Viscosidade
12.
J Mech Behav Biomed Mater ; 138: 105638, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36623403

RESUMO

INTRODUCTION: Knowledge of the nonlinear viscoelastic properties of the liver is important, but the complex tissue behavior outside the linear viscoelastic regime has impeded their characterization, particularly in vivo. Combining static compression with magnetic resonance (MR) elastography has the potential to be a useful imaging method for assessing large deformation mechanical properties of soft tissues in vivo. However, this remains to be verified. Therefore this study aims first to determine whether MR elastography can measure the nonlinear mechanical properties of ex vivo bovine liver tissue under varying levels of uniform and focal preloads (up to 30%), and second to compare MR elastography-derived complex shear modulus with standard rheological measurements. METHOD: Nine fresh bovine livers were collected from a local abattoir, and experiments were conducted within 12hr of death. Two cubic samples (∼10 × 10 × 10 cm3) were dissected from each liver and imaged using MR elastography (60 Hz) under 4 levels of uniform and focal preload (1, 10, 20, and 30% of sample width) to investigate the relationship between MR elastography-derived complex shear modulus (G∗) and the maximum principal Right Cauchy Green Strain (C11). Three tissue samples from each of the same 9 livers underwent oscillatory rheometry under the same 4 preloads (1, 10, 20, and 30% strain). MR elastography-derived complex shear modulus (G∗) from the uniform preload was validated against rheometry by fitting the frequency dependence of G∗ with a power-law and extrapolating rheometry-derived G∗ to 60 Hz. RESULTS: MR elastography-derived G∗ increased with increasing compressive large deformation strain, and followed a power-law curve (G∗ = 1.73 × C11-0.38, R2 = 0.96). Similarly, rheometry-derived G∗ at 1 Hz, increasing from 0.66 ± 1.03 kPa (1% strain) to 1.84 ± 1.65 kPa (30% strain, RM one-way ANOVA, P < 0.001), and the frequency dependence of G∗ followed a power-law with the exponent decreasing from 0.13 to 0.06 with increasing preload. MR elastography-derived G∗ was 1.4-3.1 times higher than the extrapolated rheometry-derived G∗ at 60 Hz, but the strain dependence was consistent between rheometry and MR elastography measurements. CONCLUSIONS: This study demonstrates that MR elastography can detect changes in ex vivo bovine liver complex shear modulus due to either uniform or focal preload and therefore can be a useful technique to characterize nonlinear viscoelastic properties of soft tissue, provided that strains applied to the tissue can be quantified. Although MR elastography could reliably characterize the strain dependence of the ex vivo bovine liver, MR elastography overestimated the complex shear modulus of the tissue compared to rheological measurements, particularly at lower preload (<10%). That is likely to be important in clinical hepatic MR elastography diagnosis studies if preload is not carefully considered. A limitation is the absence of overlapping frequency between rheometry and MR elastography for formal validation.


Assuntos
Técnicas de Imagem por Elasticidade , Animais , Bovinos , Técnicas de Imagem por Elasticidade/métodos , Elasticidade , Viscosidade , Fígado/diagnóstico por imagem , Reologia
13.
J R Soc Interface ; 20(198): 20220598, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36628528

RESUMO

The superiority of many natural surfaces at resisting soft, sticky biofoulants have inspired the integration of dynamic topography with mechanical instability to promote self-cleaning artificial surfaces. The physics behind this novel mechanism is currently limited to elastic biofoulants where surface energy, bending stiffness and topographical wavelength are key factors. However, the viscoelastic nature of many biofoulants causes a complex interplay between these factors with time-dependent characteristics such as material softening and loading rate. Here, we enrich the current elastic theory of topographic de-adhesion using analytical and finite-element models to elucidate the nonlinear, time-dependent interaction of three physical, dimensionless parameters: biofoulant's stiffness reduction, the product of relaxation time and loading rate, and the critical strain for short-term elastic de-adhesion. Theoretical predictions, in good agreement with numerical simulations, provide insight into tuning these control parameters to optimize surface renewal via topographic de-adhesion in the viscoelastic regime.


Assuntos
Modelos Biológicos , Elasticidade , Viscosidade , Análise de Elementos Finitos , Estresse Mecânico
14.
Sci Rep ; 13(1): 596, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36631505

RESUMO

Active particles (living or synthetic) often move through inhomogeneous environments, such as gradients in light, heat or nutrient concentration, that can lead to directed motion (or taxis). Recent research has explored inhomogeneity in the rheological properties of a suspending fluid, in particular viscosity, as a mechanical (rather than biological) mechanism for taxis. Theoretical and experimental studies have shown that gradients in viscosity can lead to reorientation due to asymmetric viscous forces. In particular, recent experiments with Chlamydomonas Reinhardtii algae swimming across sharp viscosity gradients have observed that the microorganisms are redirected and scattered due to the viscosity change. Here we develop a simple theoretical model to explain these experiments. We model the swimmers as spherical squirmers and focus on small, but sharp, viscosity changes. We derive a law, analogous to Snell's law of refraction, that governs the orientation of active particles in the presence of a viscosity interface. Theoretical predictions show good agreement with experiments and provide a mechanistic understanding of the observed reorientation process.


Assuntos
Chlamydomonas reinhardtii , Modelos Teóricos , Viscosidade , Movimento (Física) , Reologia
15.
Anal Chim Acta ; 1239: 340721, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36628771

RESUMO

Viscosity and sulfur dioxide levels are important factors to evaluate the changes of cell micro-environment because a series of diseases usually occur when they are abnormal. At present, dual-response probes that can detect both viscosity and sulfur dioxide are rare. Therefore, we developed a novel fluorescent probe CBN for simultaneous detection of sulfur dioxide and viscosity. Besides, probe CBN could target lysosome of which normal function will be disrupted by the abnormality of viscosity. Therefore, probe CBN has the potential to be served as an effective biological tool to monitor the intracellular micro-environment.


Assuntos
Corantes Fluorescentes , Dióxido de Enxofre , Humanos , Viscosidade , Lisossomos , Células HeLa
16.
Clin Nutr ESPEN ; 53: 214-223, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36657916

RESUMO

BACKGROUND AND AIM: Aspiration and dysphagia are frequent in critically ill patients, and evidence of the validity of bedside screening tests is lacking. This study evaluated the modified Volume-Viscosity Swallow Test (mV-VST) as a screening tool for aspiration and dysphagia in intensive care unit patients. METHODS: An observational, prospective longitudinal cohort single-center study included patients older than 18 years old, on mechanical ventilation for at least 48 h, conscious and cooperative. Patients had been admitted in intensive care between March 2016 and August 2019 at a university hospital in Spain. Data from the mV-VST and the flexible endoscopic evaluation of swallowing (FEES) test in extubated and tracheostomized patients were collected; the ROC curve was obtained for each group, and the sensitivity (Se), specificity (Sp), positive (pPV) and negative (nPV) predictive values of mV-VST were calculated and compared with the FEES results. We calculated percentages and 95% confidence intervals (CI) for qualitative variables and means or medians for quantitative variables according to the Shapiro-Wilk test. A univariate analysis identified dysphagia risk factors in each group. RESULTS: The study included 87 patients: 44 extubated and 43 tracheostomized with similar age, body mass index, Sequential Organ Failure Assessment, Charlson comorbidity index, type and reason for admission. Aspiration with FEES was significantly higher in extubated patients than in tracheostomized patients, 43.2% vs. 23.2%, respectively, p = 0.04. With the mV-VST, aspiration was detected in 54.5% of extubated patients and in 39.5% of tracheostomized patients. In the extubated group, the Se of mV-VST to detect aspiration was 89.5%, Sp was 72%, and nPV was 90%. In the tracheostomized group, Se was 100%, Sp was 78.8%, and nPV was 100%. The ROC curve showed that mV-VST similarly identifies aspiration in extubated and tracheostomized patients. CONCLUSIONS: Dysphagia and aspiration are frequent amongst patients in intensive care after mechanical ventilation. The mV-VST is a valid screening tool to detect aspiration and dysphagia in extubated and tracheostomized patients.


Assuntos
Transtornos de Deglutição , Humanos , Adolescente , Transtornos de Deglutição/diagnóstico , Transtornos de Deglutição/etiologia , Estudos Prospectivos , Viscosidade , Estado Terminal , Deglutição
17.
ACS Appl Mater Interfaces ; 15(3): 3699-3712, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36633252

RESUMO

Investigation of a lubrication behavior of phase change materials (PCM) can be challenging in applications involving relative motion, e.g., sport (ice skating), food (chocolates), energy (thermal storage), apparel (textiles with PCM), etc. In oral tribology, a phase change often occurs in a sequence of dynamic interactions between the ingested PCM and oral surfaces from a licking stage to a saliva-mixed stage at contact scales spanning micro- (cellular), meso- (papillae), and macroscales. Often the lubrication performance and correlations across length scales and different stages remain poorly understood due to the lack of testing setups mimicking real human tissues. Herein, we bring new insights into lubrication mechanisms of PCM using dark chocolate as an exemplar at a single-papilla (meso)-scale and a full-tongue (macro) scale covering the solid, molten, and saliva-mixed states, uniting highly sophisticated biomimetic oral surfaces with in situ tribomicroscopy for the first time. Unprecedented results from this study supported by transcending lubrication theories reveal how the tribological mechanism in licking shifted from solid fat-dominated lubrication (saliva-poor regime) to aqueous lubrication (saliva-dominant regime), the latter resulted in increasing the coefficient of friction by at least threefold. At the mesoscale, the governing mechanisms were bridging of cocoa butter in between confined cocoa particles and fat coalescence of emulsion droplets for the molten and saliva-mixed states, respectively. At the macroscale, a distinctive hydrodynamic viscous film formed at the interface governing the speed-dependent lubrication behavior indicates the striking importance of multiscale analyses. New tribological insights across different stages and scales of phase transition from this study will inspire rational design of the next generation of PCM and solid particle-containing materials.


Assuntos
Saliva , Língua , Humanos , Lubrificação , Fricção , Viscosidade
18.
Zhongguo Gu Shang ; 36(1): 38-42, 2023 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-36653004

RESUMO

OBJECTIVE: To observe the clinical efficacy of targeted sealing with high viscosity bone cement and secondary injection of low viscosity bone cement in the treatment of OVCFs patients with the fracture lines involved vertebral body margin. METHODS: The elderly patients who underwent vertebroplasty for osteoporotic vertebral compression fractures from January 2019 to September 2021 were selected as the screening objects. Through relevant standards and further CT examination, 56 patients with fracture lines involving the anterior wall or upper and lower endplates of the vertebral body were selected for the study. There were 21 males and 35 females, aged from 67 to 89 years old with an average of (76.58±9.68) years. All 56 patients underwent secondary injection of bone cement during operation. Only a small amount of high viscosity cement was targeted to seal the edge of the vertebral body for the first time, and low viscosity cement was injected to the vertebral bodies during second bolus with well-distributed. The operation time, bone cement volume and bone cement leakage were recorded, and the pain relief was evaluated by visual analogue scale (VAS). RESULTS: All patients were followed up for more than 3 months and the surgeries were successfully complete. The operation time was (50.41±10.30) min and the bone cement volume was (3.64±1.29) ml. The preoperative VAS was (7.21±2.41) points, which decreased significantly to (2.81±0.97) points 3 days after operation(P<0.05). Among the 56 patients, 2 cases(3.57%) had bone cement leakage, 1 case leaked to the paravertebral vein, and 1 case slightly bulged to the paravertebral through the crack when plugging the vertebral crack. Both patients had no obvious clinical symptoms. CONCLUSION: In vertebroplasty surgery, targeted sealing of high viscosity bone cement and secondary injection of low viscosity bone cement can reduce intraoperative bone cement leakage and improve the safety of operation.


Assuntos
Fraturas por Compressão , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Vertebroplastia , Masculino , Feminino , Humanos , Idoso , Idoso de 80 Anos ou mais , Cimentos Ósseos/uso terapêutico , Fraturas por Compressão/cirurgia , Fraturas por Compressão/etiologia , Fraturas da Coluna Vertebral/cirurgia , Viscosidade , Fraturas por Osteoporose/cirurgia , Estudos Retrospectivos , Vertebroplastia/efeitos adversos , Resultado do Tratamento
19.
Anal Chem ; 95(4): 2382-2389, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36653196

RESUMO

Thrombus are blood clots formed by abnormal hemostasis in blood vessels and are closely associated with various diseases such as pulmonary embolism, myocardial infarction and stroke. Early diagnosis and treatment of thrombus is the key to reducing the high risk of thrombotic disease. Given that early thrombus is small in early size, free instability, wide regional distribution and fast formation, it is urgent to develop all-inclusive detection methods that combine high signal-to-noise ratio, in situ dynamic and rapid in-depth tissue imaging. Near-infrared (NIR) fluorescence imaging, with its excellent high spatiotemporal resolution and tissue penetration depth, is a powerful technique for direct visualization of thrombotic events in situ. Considering the fibrin highly expressed in the thrombus is a typical thrombotic target. Moreover, the viscosity of the thrombus is markedly higher than its surroundings. Therefore, we developed a fibrin-targeting and viscosity-activating thrombus NIR fluorescent probe (TIR-V) for high-resolution and high-sensitivity in situ lighten-up thrombus. TIR-V has the advantages of good thrombus targeting, significant "off-on" fluorescence specific response to viscosity, bright NIR fluorescence and good biocompatibility. The thrombus is clearly delineated by a high signal-to-noise ratio NIR fluorescence imaging, enabling imaging detection and precise navigation of thrombotic regions. This work demonstrates the potential of TIR-V as a bifunctional probe for definitive diagnostic imaging and direct navigation of thrombotic lesions in clinical applications.


Assuntos
Trombose , Trombose Venosa , Humanos , Fluorescência , Viscosidade , Trombose Venosa/patologia , Trombose/diagnóstico por imagem , Fibrina , Corantes Fluorescentes , Imagem Óptica
20.
Biosensors (Basel) ; 13(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36671911

RESUMO

Quantifying the viscosity of a gas is of great importance in determining its properties and can even be used to identify what the gas is. While many techniques exist for measuring the viscosities of gases, it is still challenging to probe gases with a simple, robust setup that will be useful for practical applications. We introduce a facile approach to estimating gas viscosity using a strain gauge inserted in a straight microchannel with a height smaller than that of the gauge. Using a constrained geometry for the strain gauge, in which part of the gauge deforms the channel to generate initial gauge strain that can be transduced into pressure, the pressure change induced via fluid flow was measured. The change was found to linearly correlate with fluid viscosity, allowing estimation of the viscosities of gases with a simple device.


Assuntos
Gases , Viscosidade , Pressão
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