Bolus Formation Research Articles

Imaging of Tongue Carcinoma: About 20 Cases

The tongue enables taste and plays a critical role in formation of food bolus and deglutition. The tongue is also crucial for speech and the earliest sign of tongue paresis is a change in the quality of speech. Given the importance of the tongue, tongue carcinoma should be accurately staged in order to optimise treatment options and preserve organ function. The intent of this review is to familiarise radiologists with the pertinent anatomy of the tongue and the behaviour of tongue carcinoma so as to map malignant infiltration accurately.

Oral processing of bakery products: An overview of current status and future outlook

Food oral processing (FOP) is an emerging research topic that allows a better comprehension of the relation between intrinsic food factors (physicochemical and sensory properties), and human physiology and eating behaviours. FOP can then help in the design of novel and healthier food to meet both quality requirements and consumer needs. In this context, this review presents the current state of knowledge and new insights for future research concerning FOP of bakery products. The application of FOP in bakery science is new, with different protocols and related evaluation being applied, as detailed in this review. The current knowledge shows that bread structure and texture, influenced by formulation and process conditions, as well as the crust and shortenings present, impact bread breakdown and bolus formation, sensory perception, and food physiological effects such as glycaemic response, satiation, and satiety. For a better comprehension of oral processing, cross-modal perception between sensory attributes is used to understand consumer perception and this is carried out using both in vivo, and in vitro methods. This review highlighted the great potential of FOP to assist researchers and producers to face the current challenges relating to i – salt, fat and sugar reduction in bakery products to fulfil current food nutrition policies, ii – the design of healthier bakery products, and iii – the development of bakery products for consumers with special dietary requirements and ageing needs. In conclusion, FOP shows great potential to assist in the development of novel and healthier foods to meet actual food nutrition policies and consumer needs and should be more explored in bakery science and production.

Impact of salivary flow inhibition on masticatory behaviours in healthy individuals.

It remains unclear how the salivary flow and the fat content of food affect bolus formation during mastication. We aimed to clarify: (1) how hyposalivation affects jaw-closing and hyoid-elevating muscle activities in bolus formation, and (2) if the effect of hyposalivation on muscle activity depends on the fat content of food. Eighteen healthy male volunteers were instructed to freely ingest four test foods: Plain, Fat without seasoning, Fat with seasoning, and Soft rice crackers. Masseter and suprahyoid electromyographic activities were recorded before and 30 min after the administration of atropine sulfate, a muscarinic receptor antagonist that induces hyposalivation. Hyposalivation extended the masticatory duration significantly in all the test foods except Fat with seasoning. Masticatory cycle time was significantly longer with vs without hyposalivation for the Soft (p = .011). Suprahyoid activity/cycle was significantly greater with vs without hyposalivation (p = .013). Masticatory cycle time was significantly longer at the late stage with vs without hyposalivation for the Soft (p < .001). Suprahyoid activity/cycle was significantly greater at the middle (p = .045) and late stages (p = .002) with vs without hyposalivation for the Soft and greater at the late stage with vs without hyposalivation for the Plain (p = .043). Changes in masticatory cycle time and suprahyoid activity/cycle for these foods had significantly positive relationship (p < .001). Hyposalivation-induced changes in masticatory behaviours resulted from the middle and late stage suprahyoid activity. Fat content and seasoning compensate for salivary flow inhibition.

Nonlinear Tissue Permeability Drives Tissue Pressure and Injection Distribution: A Computational Investigation of Subcutaneous Injections.

There is a significant opportunity to expand the understanding of subcutaneous injection mechanics with an aim to increase injectable volume while controlling tissue strain and associated subject pain. Computational modeling can evaluate the mechanics of subcutaneous injections as a supplement to experimental, animal and clinical studies. The objectives of this study are to (1) develop a computational model for subcutaneous injection in tissue, (2) investigate the influence anisotropic tissue permeability has on bolus formation, and (3) explore the effects that injection flow rate and viscosity have on injection flow and tissue strain. Poroelastic models with subsurface flow were implemented in finite element software (COMSOL, ABAQUS). Pore pressure and injectate distribution showed excellent agreement with experimental results when evaluated at multiple injection rates (20 ml/hr, 120 ml/hr and 360 ml/hr). Including the anisotropy of tissue permeability causes the injectate to preferentially spread horizontally, similar to experimentally observed bolus distributions. Cases are presented to provide additional insight into injection mechanics, including variations on the delivery rate, the injection volume, viscosity and the thickness of the subcutaneous layer. The results support the use of computational modeling as a valid tool for understanding tissue strains and injectate distributions for large volume injections.

On the rheological and sensory properties of a novel natural salivary substitute

The prevalence of xerostomia, the sensation of dry mouth, is estimated at 20 % in the general population and up to 50 % in older adults. Saliva plays different roles during bolus formation: lubrication, mixing, coating, hydration, dissolution, and comminution of food particles. This study proposes and tests artificial saliva formulations mimicking human saliva rheological and sensory perceptions. Shear and extensional rheology were assessed to select the type of formulation closest to saliva rheological characteristics. After evaluating three alternative sources, an extract simulating saliva rheology was produced from flax seeds. Friction coefficient and rheological properties, such as flow curves, relaxation times, and Trouton ratios, were compared favorably with human saliva. The sensory evaluation demonstrated that flaxseed extracts induce perceived mouth hydration, slipperiness, and adhesion exceeding that of human saliva. The flaxseed extract proposed in this can i) be used to study in vitro food oral processing and ii) pave the way to novel natural salivary substitutes to alleviate the symptoms of xerostomia.

Relationship Between Submental Superficial Layer Hardness and Tongue Pressure Determined Using a Tissue Durometer.

Aging affects the tongue and suprahyoid muscles, causing dysphagia and undernutrition. We hypothesized that tongue function would affect submental superficial layer hardness. Tongue movements during water retention between the tongue and palate are the same as those required during bolus formation, involving internal and external tongue muscle movement. In 28 healthy adults (14 males, 14 females, average age 28.7 ± 2.9 years), we measured the submental superficial layer characteristics (frequency [tension], stiffness, decrement [inverse of resilience], relaxation, and creep [deformation over time]) using a simple tissue durometer (MyotonPRO®), and examined their relationship with maximum voluntary tongue pressure. The tissue durometer sensor was placed in the submental region, where there is no intervening bone. Measurements were performed at rest and while retaining 5 mL water. Tongue pressure was measured using a tongue pressure-measuring device. The submental superficial layer hardness differed significantly between rest and during water retention. During water retention, frequency and stiffness were high, while decrement, relaxation, and creep were low. When pressure is applied to the palate, such as during water retention the inner tongue muscle, which changes the tongue's shape, and the outer tongue muscle, which moves the tongue laterally, are active. However, the change in the hardness of the submental superficial layer during water retention may be related to the suprahyoid muscles that are present in this layer. The results of this study suggested that the hardness of the submental superficial layer changed during water retention, and that tongue movement could be measured from outside the mouth.

Complex cilia-generated flow of hybrid nanofluid with electroosmosis, viscous dissipation and slippage

In this study, we investigated how electroosmsis, viscous dissipation, and slippage affect the peristaltic flow of complex cilia-generated flow of hybrid nanofluid in a ciliated tube. The complex cilia-generated flow is characterized by a complex sinusoidal wave that transmits along the wall of the tube with a uniform speed having distinct amplitudes. The main objective of this work is to examine how this complex cilia on the wall drives the hybrid nanofluid flow under electroosmosis. The Helmholtz–Smoluchowski equation is used to model the electroosmosis, and the Poisson equation is solved analytically using the Debye-Huckel approximation. The lubrication approach is utilized to simplify the governing equations. The governing non-dimensional equations for hybrid nanofluid are solved exactly using the DSolve command of Mathematica. The results are presented graphically to accomplish the theoretical results from the complex-cilia wave evolution from the necessary flow parameters in an asymmetric tube. The study shows that increasing the electroosmotic parameter leads to an increase in the velocity profile at the boundary and a decrease in the middle of the tube. Conversely, the Helmholtz–Smoluchowski velocity parameter has the opposite effect. The Brinkman parameter increases the temperature of the hybrid nanofluid. The study also presents a graphical analysis of pressure rise and pressure gradient for various values of the parameters. The pressure rise against volumetric flow is rate and pressure gradient increases by increasing the electroosmotic parameter and Helmholtz-Smoluchowski parameter, while it decreases for increasing the velocity slip parameter. The streamlines are drawn to study the trapping phenomena of blood in the hybrid nanofluid flow in an asymmetric tube by the formation of bolus and the division of streamlines. It is observed that the size and number of bolus close to the artery walls increases for electroosmotic parameter while reverse behavior is observed for Helmholtz-Smoluchowski parameter. The tabular presentation of the heat transfer coefficient at the wall is presented. The current results can be used in bio mathematical models to control fluid flow through micro-channels and to investigate ways to cure artery blockages and cancer tumors in biomedicine. The study can also be used to design and optimize microfluidic devices for drug delivery, lab-on-a-chip devices, and other biomedical applications.

Novel study of inertial forces on MHD peristaltically driven micropolar fluid through porous-saturated asymmetric channel: Finite Galerkin approach

This focused study investigates the peristaltic motion of a micropolar fluid within an uneven channel filled with a porous medium, incorporating an orthogonal magnetic field to the flow. This research diverges from the traditional assumptions of lubrication theory. The governing equations, encompassing the physical characteristics of micropolar fluid peristalsis, are transformed into nonlinear coupled partial differential equations. These equations are solved using the finite element method, considering inertial effects, such as non-zero wave and Reynolds numbers. This study delves into the influence of various crucial parameters on axial velocity, pressure gradient, microrotation, and stream function, presenting graphical representations. Notably, the incremental phase shift causes an intermingling of upper and lower streamlines within both halves of the channel. As the Reynolds number increases, there is an observed reduction in bolus size, particularly at maximum phase shifts, with a tendency to move toward the central region. An increase in Hartmann number leads the bolus formation to vanish in both channels, reduces microrotation, and leads to increased pressure. Vorticity lines intensify and incline toward the peristaltic walls. An increase in the permeability parameter amplifies velocity, microrotation, volume, and bolus formation regardless of phase differences while countering pressure elevation per wavelength. Reduced concavity is observed as vorticity lines disperse across the entire area.

Analyzing Single Peristaltic Wave Behavior in Ureter with Variable Diameters: A Ureterdynamic Study

Ureters are muscular tubes that transport urine from the kidney to the bladder. The peristalsis wave is responsible for carrying urine to the bladder. With the regular appearance of peristalsis, areas with anatomic narrowing junctions are crucial for ureteral diseases. A three-dimensional flow analysis is performed for different time steps to understand the effect of the urine bolus formation and the reflux phenomenon on variable diameter ureters. For the constant and variable diameter ureter, the pressure is obtained behind and in front of the propagating bolus respectively. The peristalsis wave creates the high-velocity of a jet in the neck region of the ureter. The contraction produces the trapping of the bolus leading to adverse flow in the contraction region. By virtue tapering, the high-pressure gradient builds up, leading to high wall shear in the ureter. The main goal is to determine the pressure, velocity, gradient pressure, and shear force on the ureter wall during peristaltic motion. These parameters are very important for clinicians to understand its effect in the unobstructed variable diameter ureter. This article may help to build a medical device for engineers. The physical significance of this information lies in its profound insights into the biomechanics and functionality of the ureters, which are essential components of the human urinary system.

Shoaling Internal Solitary Waves and the Formation of Boluses

Shoaling Internal Solitary Waves and the Formation of Boluses

Merkel cells and keratinocytes in oral mucosa are activated by mechanical stimulation.

The detection of mechanical qualities of foodstuffs is essential for nutrient acquisition, evaluation of food freshness, and bolus formation during mastication. However, the mechanisms through which mechanosensitive cells in the oral cavity transmit mechanical information from the periphery to the brain are not well defined. We hypothesized Merkel cells, which are epithelial mechanoreceptors and important for pressure and texture sensing in the skin, can be mechanically activated in the oral cavity. Using live-cell calcium imaging, we recorded Merkel cell activity in ex vivo gingival and palatal preparations from mice in response to mechanical stimulation. Merkel cells responded with distinct temporal patterns and activation thresholds in a region-specific manner, with Merkel cells in the hard palate having a higher mean activation threshold than those in the gingiva. Unexpectedly, we found that oral keratinocytes were also activated by mechanical stimulation, even in the absence of Merkel cells. This indicates that mechanical stimulation of oral mucosa independently activates at least two subpopulations of epithelial cells. Finally, we found that oral Merkel cells contribute to preference for consuming oily emulsion. To our knowledge, these data represent the first functional study of Merkel-cell physiology and its role in flavor detection in the oral cavity.

A Novel Approach to Evaluate Robotic in Vitro Chewing Effect on Food Bolus Formation Using the GLCM Image Analysis Technique

A Novel Approach to Evaluate Robotic in Vitro Chewing Effect on Food Bolus Formation Using the GLCM Image Analysis Technique

Relationship between the perception of complex textural attributes and the bolus properties of cheese

In the present study, we investigated the relations between compositional and physical properties, bolus formation and texture perception to better understand complex sensory attributes of cheese. Five commercial cheeses with two fat content levels and varying ripening time were evaluated for texture and flavor using a sensory panel (n = 77), and were also subjected to compositional analysis and instrumental texture characterization. In addition, the properties of boli of the same cheeses expectorated by 20 individuals, including composition, particle size distribution, mechanical properties, and lubrication properties were determined.Our results confirmed that simple texture attributes such as hardness, brittleness and elasticity are mostly related to the mechanical properties of cheeses, such as fracture strain and resilience. To explain complex attributes, like smoothness, creaminess and fattiness, bolus properties became more relevant. Bolus formation was largely influenced by the fat content and the hardness of the cheese. As fat melted during mastication, a higher fat content contributed to the formation of a softer, more cohesive and better lubricating bolus, and the cheeses were perceived as smoother and creamier. When the cheese bolus contained more hard particles, the bolus provided less lubrication (higher μ), and the cheeses were perceived as less smooth. These findings offer new insights into the mechanisms behind the perception of complex texture attributes of cheese. They may contribute to engineering cheese with desired sensory properties based on indications meant to control bolus formation.

Radiative and dissipative MHD Eyring–Powell nanofluid bioconvective flow through peristaltic waves in the presence of bilateral chemical reaction with Arrhenius activation energy: Entropy optimization

The novel characteristics of nanofluids made them potentially important in the heat transfer mechanisms happening in industrial and medical processes, such as electronic devices, pharmacological techniques, hybrid combustion engines, thermal management of cars, refrigerator, chiller, temperature of gases reduction, and so on. In comparison to base fluid, these procedures have a propensity to improve thermal conductivity and convective transference of heat. This distinctive aspect has recently generated interest in nanofluids through various fluid flow models. The issue at hand involves the peristaltic flow of magnetohydrodynamics Eyring–Powell nanofluids through a microchannel containing oxytactic bacteria and nanoparticles. For a thorough analysis of irreversibility optimization, the analysis of entropy is additionally taken into consideration. To comprehend the flow physics associated with bolus formation and the effect of reflux on the micro vessel, a 3-D computational fluid dynamic analysis is performed. The effects of bilateral chemical interaction with nonlinear mixed convection and Arrhenius activation energy are considered in the present analysis. The complexity of the system was achieved through a numerical approach based on the concepts of small Reynolds number and large wavelength. The resulting nonlinear coupled differential equation system is solved numerically using the built-in command in MATHEMATICA (Parametric ND Solve Function). To perform a thorough comparative examination for various values of the considered sections of the channel, graphs have been used. Some of the investigation’s findings are the entropy profile has been improved for incremental values of Hartmann number and Brinkmann number whereas the axial velocity shows a downward trend for the highest values of the Hartmann number and the material fluid parameter.

Effect of salivary fluid characteristics on the physical features of in vitro bread bolus: From the absence of saliva to artificially simulated hypersalivation

Saliva facilitates food oral processing, bolus formation, swallowing, and sensory perception, in addition to contributing to oral health and phonation. Ageing, health affections, and polymedication are among many causes altering salivary production, modifying the mastication process, the food impregnation ratio, and in turn altering the characteristics of the bolus, swallowing, and digestion. In this in vitro work, using the AM2 masticator apparatus, which replicates the mechanical actions taking place while chewing solid foods and produces realistic food bolus in various oral conditions, we investigated the effect of salivary fluid characteristics, i.e., composition, quantity (from absence to hypersalivation), temperature, and enzymatic action, on the physical characteristics (i.e., particle size distribution (PSD), bolus mass, salivary fluid content) of in vitro boluses of Traditional French baguette.A ready-to-swallow bolus of baguette displayed on average a d50 value (median particle size by mass) of 4.1 ± 0.4 mm, with saliva fluid constituting ∼ 35 % of the final bolus mass. The absence of saliva in mouth led to a deficient oral processing, forming bread boluses constituted by extremely big particles (ca. 80 % of particles had a size > 7.1 mm) that likely cannot be swallowed safely. On the contrary, an excess of saliva favoured an excessive breaking down of bread, leading to bread boluses constituted by smaller particles than those formed under healthy salivary conditions (d50 decreased from 4.1 mm to 3.1 mm), having a higher salivary fluid content (+10 %). On the other hand, the salivary fluid temperature did not affect PSD, d50, bolus mass, or salivary fluid content of in vitro bread boluses, however, the addition of human salivary α-amylase did, favouring particle size reduction (d50 decreased to 2.6 mm). Therefore, beyond the correlation between bolus hydration by saliva and food properties such as hardness and moisture content, our findings indicate that the quantity of salivary fluid present in the oral cavity and the enzymatic activity of salivary α-amylase during bread mastication significantly influence both the particle size distribution and the fluid content of bread boluses, ultimately determining the physical properties of the bolus and, therefore, potentially impacting the subsequent swallowing process.

Development and validation of a novel system that combines a new masticatory simulator and analysis method for modeling the human gummy candy masticatory process.

During mastication, food undergoes state and texture changes influenced by various mechanical properties, including compression and fracturing of the molar teeth, mixing with saliva, and oral temperature. Prior studies have explored mastication simulators, however, no studies have assessed the forces and duration applied to the molars by the food during bolus formation. In this study, we developed a novel system that integrates a masticatory simulator and analysis method to evaluate mechanical properties. We developed ORAL-MAPS which is equipped with 6-axis force sensor, pneumatic pressure control mechanism, vertical movement, molar-like module, artificial saliva injection unit, and temperature control apparatus. A gap exists between the upper and lower unit at the closest point, allowing the sensor to measure vertical upward force and duration from food, while compressed air provides constant downward pressure. We hypothesized a correlation between the total integrated muscle activity ratio obtained from the human masseter muscle electromyography (iEMG). We compared the normalized impulse obtained from ORAL-MAPS with the normalized total iEMG obtained from human studies with four different types of gummy candies. As a result, the normalized total impulse of gummy candies A, B, C, and D were 1.00 ± 0.00, 1.29 ± 0.06, 0.95 ± 0.00, and 0.39 ± 0.0, respectively. The normalized total iEMG of the same gummy candies were 1.00 ± 0.00, 1.23 ± 0.15, 0.98 ± 0.09, and 0.45 ± 0.07, respectively. Thus, no significant difference was observed between the normalized total impulse obtained in vitro and the normalized total iEMG values for masticating the gummy candies B, C, and D (p > .05).

Dynamic Instrumental and Sensory Methods Used to Link Aroma Release and Aroma Perception: A Review.

Perception of flavor is a dynamic process during which the concentration of aroma molecules at the olfactory epithelium varies with time as they are released progressively from the food in the mouth during consumption. The release kinetics depends on the food matrix itself but also on food oral processing, such as mastication behavior and food bolus formation with saliva, for which huge inter-individual variations exist due to physiological differences. Sensory methods such as time intensity (TI) or the more-recent methods temporal dominance of sensations (TDS) and temporal check-all-that-apply (TCATA) are used to account for the dynamic and time-related aspects of flavor perception. Direct injection mass spectrometry (DIMS) techniques that measure in real time aroma compounds directly in the nose (nosespace), aimed at obtaining data that reflect the pattern of aroma release in real time during food consumption and supposed to be representative of perception, have been developed over the last 25 years. Examples obtained with MS operated in chemical ionization mode at atmospheric or sub-atmospheric pressure (atmospheric pressure chemical ionization APCI or proton-transfer reaction PTR) are given, with emphases on studies conducted with simultaneous dynamic sensory evaluation. Inter-individual variations in terms of aroma release and their relevance for understanding flavor perception are discussed as well as the evidenced cross-modal interactions.

Feasibility of using a protein gel for masticatory assessment of older people

Masticatory function plays a crucial role in the breakdown of food for bolus formation and safe swallowing. Chewable silicone gel particles (Optosil) were used for assessing masticatory performance by dentists but such particles were found not suitable for older people due to its hard and dry texture and unfavored flavor. Therefore, with fast growing number of older people who have eating and swallowing difficulties, seeking a suitable model food for masticatory performance assessment becomes an important issue. This study was to develop a glucose-containing model food system for reliable evaluation of the masticatory performance. Three formulas with different amount of gelatin were used to prepare the gels and their textural properties were analyzed. A glucometer was used to measure glucose concentration in saliva. Both young adults (23.5 ± 1.1 years) and older subjects (72.9 ± 5.4 years) were asked to perform mastication tests to verify the reliability of the method. Results showed that the Gel-15% sample gave the best performance and was selected as the test food. Reliability of the current method was proved by the classical standard of Optosil method. Moreover, our findings indicated that masticatory performance was significantly positively correlated with bite force in both young and older adults (young subjects: r = 0.874, p < 0.01; older subjects: r = 0.638, p < 0.01). In conclusions, this study suggested that the newly method could accurately and efficiently measure the masticatory performance of older people.

Inertial considerations in peristaltically activated MHD blood flow model in an asymmetric channel using Galerkin finite element simulation for moderate Reynolds number

Numerically investigated analysis occupying considerations free from long wavelength and creeping flow regime has been addressed in this paper for non-Newtonian Casson fluid induced by peristaltic activity. Rheological measurements have been exposed by fluid progression in the asymmetric conduit influenced by a normally settled magnetic field. The analysis is made without implementation of the lubrication theory which allows the role of inertial forces in the flow model not addresses before. Galerkin formulated finite element method is practiced by simplifying full Navier-Stokes equations to assure the appearance of non-trivial Reynolds number and wave independence in an ongoing study. The solution hinged based on code formulated in MATLAB for velocity distribution, pressure profiles, vorticity lines, and stream function is graphically plotted. It has been deduced that inflating the Casson fluid parameter (0.1≤β≤0.5) drives an inappreciable reduction in velocity close to the central region and vorticity lines to remain unaffected. An appreciable increase in bolus formation is inspected by rising time mean flow (1.1≤Q≤1.6) with the diffusion of streamlines in the provision of a progressive phase in waves.

Clinical and Swallowing Characteristics Related With Respiratory Infection in Parkinsonism Patients.

To investigate the clinical and swallowing characteristics related to respiratory infection in patients with parkinsonism. One hundred and forty-two patients with parkinsonism who underwent videofluoroscopic swallowing studies (VFSS) were enrolled in this study. The initial clinical and VFSS characteristics were compared between patients with and without a history of respiratory infection in the past year. A multivariate logistic regression model was applied to identify clinical and swallowing characteristics related to respiratory infections. Patients with respiratory infections were older (74.75±10.20 years vs. 70.70±8.83 years, p=0.037), had a higher Hoehn and Yahr (H&Y) stage (stage IV-V, 67.9% vs. 49.1%; p=0.047), and were more likely to have a diagnosis of idiopathic Parkinson's disease (IPD) (67.9% vs. 41.2%, p=0.011) than those without respiratory infections. Among VFSS findings, bolus formation, premature bolus loss, oral transit time, pyriform sinus residues, pharyngeal wall coatings, and penetration/aspiration were significantly worse in patients with respiratory infections (p<0.05). Regarding clinical characteristics, higher H&Y stage (odds ratio [OR], 3.174; 95% confidence interval [CI], 1.226-8.216; p=0.017) and diagnosis of IPD (OR, 0.280, 95% CI, 0.111-0.706; p=0.007) were significantly related to respiratory infections in the multivariate analysis. Among VFSS findings, pyriform sinus residue (OR, 14.615; 95% CI, 2.257-94.623; p=0.005) and premature bolus loss (OR, 5.151; 95% CI, 1.047-25.338; p=0.044) were also significantly associated with respiratory infection. This study suggests that disease severity, diagnosis, pyriform sinus residue, and premature bolus loss observed in VFSS are associated with respiratory infection in patients with parkinsonism.