Free Segment Research Articles

A new potential risk factor for permanent cranial nerve injury following carotid body tumor resection

To quantify the association between the free distal segment length of the internal carotid artery (FDS-ICA) and permanent cranial nerve injury (p-CNI) following carotid body tumor (CBT) resection. This study is a case-control study. We surveyed 109 consecutive patients who underwent CBT resection between June 2015 and June 2020 at our single center. A total of 89 patients met the inclusion criteria and were selected for analysis. The FDS-ICA was measured by image post-processing software for computed tomography angiography (CTA). Postoperative p-CNI complications were evaluated using comprehensive statistical approaches. The cohort was divided into 2 groups depending on the presence of p-CNI, namely the p-CNI group (n=17) and the non-CNI group (n=79). The average FDS-ICA of patients with p-CNI complications was shorter than that of those without p-CNI complications (P<0.001). For every 1 mm increase in FDS-ICA, there was an associated decrease of 8% in the risk of p-CNI (0.92, 95% CI: 0.85 to 0.98, P<0.05). Threshold effect analysis of the FDS-ICA on p-CNI identified that the FDS-ICA was 28.7 (95% CI: 23.8 to 30.9) mm. The results of this study revealed a significant independent association between FDS-ICA and permanent postoperative cranial nerve injury complications of CBTs. Further study is warranted to confirm these results in a larger patient cohort.

PH/magnetic dual responsive Pickering emulsion stabilized by Fe3O4@SiO2@chitosan nanoparticles.

In recent years, Pickering emulsifiers have been widely used in various production fields due to their excellent structural stability, biocompatibility and environmental friendliness. For some applications, it is required that the emulsifier can quickly respond to environmental stimuli and control the transition between stable and unstable emulsions. In this paper, we report a novel composite Pickering emulsifier with Fe3O4 as the core and magnetic response recognition body, silica as the intermediate protective layer, and chitosan (CS) of different molecular weights to endow solid particles with surface activity and pH-responsive properties. This emulsifier can stabilize the emulsion in the emulsion system with deionized water as the aqueous phase and liquid paraffin as the oil phase and can control the demulsification of the formed emulsion under the dual pH/magnetic stimulation. The experimental results show that Fe3O4@SiO2@CS has good paramagnetism and pH responsiveness. The particle size of the composite emulsifier nanoparticles is between 90 nm and 120 nm, and the best stabilizing effect of the emulsion is achieved when the dosage is 0.5 wt%. In the pH range of 3-11, the emulsifier can rapidly demulsify a stable paraffin oil-water emulsion system under the action of a magnetic field of strength 0.4 T. The pH response of the emulsifier is as follows: when pH ≤ 2, the system can form a stable emulsion, which is composed of fully protonated chitosan as a free chain segment and Fe3O4@SiO2. Emulsion stabilization was achieved with monolithic Fe3O4@SiO2@CS as an emulsifier at pH > 2, and demulsification was achieved at pH ≈ pKb (CS) at 298 K. The research in this paper can provide a feasible idea and synthesis method for the preparation of organic-inorganic composite structure emulsifier.

Holography of geodesic flows, harmonizing metrics, and billiards' dynamics

For a traversing vector field $v$ on a compact $(n+1)$-manifold $X$ with boundary, we use closed $v$-invariant differential $n$-forms $\Theta$ to define measures $\mu_\Theta$ on the boundary $\partial X$, such that the $v$-flow generated causality map $C_v: \partial^+X(v) \to \partial^-X(v)$ preserves $\mu_\Theta$. In combination with a $\mu_\Theta$-preserving involution $\tau: \partial X \to \partial X$, which maps $\partial^-X(v)$ to $\partial^+X(v)$, the proto-billiard map $B_{v, \tau} := \tau \circ C_v$ is a measure-preserving transformation of $\partial^+X(v)$. We study the dynamical system $(\partial^+X(v), B_{v, \tau})$. Let $(M, g)$ be a Riemannian $n$-manifold with boundary, where $g$ is a non-trapping metric. Let $SM$ be the space of the spherical tangent to $M$ bundle, and $v^g$ the geodesic vector field on $SM$. We apply our treatment of $C_v$ and $(\partial^+X(v), B_{v, \tau})$ to the scattering maps $C_{v^g}$ and billiard maps $B_{v^g, \tau}$, where $\tau$ is generated by the reflection of unit tangent vectors with respect to $\partial M$. As a result, we getting a variety of holography theorems that tackle the inverse scattering problems for $C_{v^g}$ and theorems that describe the dynamics of $B_{v^g, \tau}$. Our main tool is the Lyapunov function $F: SM \to \mathbf R$ for $v^g$ and the metrics $g^\bullet$ on $SM$ that make $dF$ harmonic. For such metrics, we get isoperimetric inequalities $vol_{g^\bullet}(SM) \leq vol_{g^\bullet |}(\partial(SM))$. Assuming ergodicity of $B_{v^g, \tau}$ and non-trapping of $g$, we also get formulas for the average length of free geodesic segments in $M$.

Formation of hotel and restaurant services for rural green tourism enterprises

The subject of the research is the theoretical and practical aspects of the development of hotel and restaurant services of enterprises of rural green tourism. The purpose of the article is to substantiate the prospects for the development of hotel and restaurant services of rural green tourism enterprises, to determine their features and use in administration and management. The methodological basis of the article was both general scientific and special methods of scientific knowledge. The article used scientific research methods: historical, system-structural analysis and synthesis, monographic, statistical-economic, problem-targeted. Results of the article. It is noted that the implementation of functions, the provision of services by rural green tourism enterprises and their focus on the hotel and restaurant direction of business are based on the presence and use of significant tourism and recreation potential on the one hand and a relatively free market segment for small businesses in this area on the other. It is substantiated that rural green tourism is integrated into the general structure of tourist and hotel-restaurant activities and allows providing services even where it is not economically feasible to build separate hotels and restaurants. It was determined that the concentration of efforts of rural settlements and other small enterprises of rural green tourism mainly on hotel and restaurant services requires them to improve the quality of such services, to observe high sanitary and hygienic standards; security conditions; appropriate level of service; training of hosts and/or their employees in hospitality, tact, business communication; certain aesthetics and style of places of accommodation and food. Field of application of results. The results can be used by tourism enterprises, territorial communities, regional and state authorities, public organizations, individual entrepreneurs and activists, institutions of higher education, scientific institutions. Conclusions. Combined efforts are achieving changes for the better in the field of service, tourism, and the hotel and restaurant industry. And this, at the same time, is a significant contribution to the development of the village. An example can be the creation of local branches of the Association for the Development of Rural Green Tourism in the administrative regions of the country, associations of citizens interested in the development of infrastructure for rural green tourism, etc. Thus, we can assert the existence of a "multiplier effect" from rural tourism for both the hotel and restaurant business and for the formation of a special multifunctional model of the development of rural areas.

Evolution of nonlinear perturbations for a fluid flow with a free boundary. Exact results

The problem of a plane unsteady potential flow of an ideal incompressible fluid bounded by free boundary segments with a constant pressure and by solid walls moving in accordance with a known law is considered. External forces are absent, and capillary forces are neglected. An approach to constructing exact solutions for this type of problem is proposed. The corresponding solutions can be treated as nonlinear perturbations of a certain base flow. As an example of the application of this approach, nonlinear perturbations in a known problem of a fluid flow with a linear velocity field in the region bounded by a straight-line free boundary and parallel approaching or receding solid walls are considered. It is demonstrated that perturbations grow, which leads to variants of the formation of singularities on the free surface of the fluid within a finite time: formation of droplets, bubbles or cusps. A solution describing the collapse of a bubble in a fluid layer bounded by two approaching solid walls has also been found and studied. Thus, a new method of studying nonlinear stability of complicated unsteady fluid flows with combined boundary conditions is proposed and tested.

Microstates in multiple sclerosis: an electrophysiological signature of altered large-scale networks functioning?

Multiple sclerosis has a highly variable course and disabling symptoms even in absence of associated imaging data. This clinical-radiological paradox has motivated functional studies with particular attention to the resting-state networks by functional MRI. The EEG microstates analysis might offer advantages to study the spontaneous fluctuations of brain activity. This analysis investigates configurations of voltage maps that remain stable for 80-120 ms, termed microstates. The aim of our study was to investigate the temporal dynamic of microstates in patients with multiple sclerosis, without reported cognitive difficulties, and their possible correlations with clinical and neuropsychological parameters. We enrolled fifty relapsing-remitting multiple sclerosis patients and 24 healthy subjects, matched for age and sex. Demographic and clinical data were collected. All participants underwent to high-density EEG in resting-state and analyzed 15 min free artefact segments. Microstates analysis consisted in two processes: segmentation, to identify specific templates, and back-fitting, to quantify their temporal dynamic. A neuropsychological assessment was performed by the Brief International Cognitive Assessment for Multiple Sclerosis. Repeated measures two-way ANOVA was run to compare microstates parameters of patients versus controls. To evaluate association between clinical, neuropsychological and microstates data, we performed Pearsons' correlation and stepwise multiple linear regression to estimate possible predictions. The alpha value was set to 0.05. We found six templates computed across all subjects. Significant differences were found in most of the parameters (global explained variance, time coverage, occurrence) for the microstate Class A (P < 0.001), B (P < 0.001), D (P < 0.001), E (P < 0.001) and F (P < 0.001). In particular, an increase of temporal dynamic of Class A, B and E and a decrease of Class D and F were observed. A significant positive association of disease duration with the mean duration of Class A was found. Eight percent of patients with multiple sclerosis were found cognitive impaired, and the multiple linear regression analysis showed a strong prediction of Symbol Digit Modalities Test score by global explained variance of Class A. The EEG microstate analysis in patients with multiple sclerosis, without overt cognitive impairment, showed an increased temporal dynamic of the sensory-related microstates (Class A and B), a reduced presence of the cognitive-related microstates (Class D and F), and a higher activation of a microstate (Class E) associated to the default mode network. These findings might represent an electrophysiological signature of brain reorganization in multiple sclerosis. Moreover, the association between Symbol Digit Modalities Test and Class A may suggest a possible marker of overt cognitive dysfunctions.

Cardiac magnetic resonance imaging in patients with left bundle branch block: Patterns of dyssynchrony and implications for late gadolinium enhancement imaging.

Left bundle branch block (LBBB) is a ventricular conduction delay with high prevalence. Aim of our study is to identify possible recurring patterns of artefacts in late gadolinium enhancement (LGE) imaging in patients with LBBB who undergo cardiac magnetic resonance imaging (MRI) and to define parameters of mechanical dyssynchrony associated with artefacts in LGE images. Fifty-five patients with LBBB and 62 controls were retrospectively included. Inversion time (TI) scout and LGE images were reviewed for artefacts. Dyssynchrony was identified using cardiac MRI by determining left ventricular systolic dyssynchrony indices (global, septal segments, and free wall segments) derived from strain analysis and features of mechanical dyssynchrony (apical rocking and septal flash). Thirty-seven patients (67%) with LBBB exhibited inhomogeneous myocardial nulling in TI scout images. Among them 25 (68%) patients also showed recurring artefact patterns in the septum or free wall on LGE images and artefacts also persisted in 18 (72%) of those cases when utilising phase sensitive inversion recovery. Only the systolic dyssynchrony index of septal segments allowed differentiation of patient subgroups (artefact/no artefact) and healthy controls (given as median, median ± interquartile range); LBBB with artefact: 10.44% (0.44-20.44%); LBBB without artefact: 6.82% (-2.18-15.83%); controls: 4.38% (1.38-7.38%); p < 0.05 with an area under the curve of 0.863 (81% sensitivity, 89% specificity). Septal flash and apical rocking were more frequent in the LBBB with artefact group than in the LBBB without artefact group (70 and 62% versus 33 and 17%; p < 0.05). Patients with LBBB show recurring artefact patterns in LGE imaging. Use of strain analysis and evaluation of mechanical dyssynchrony may predict the occurrence of such artefacts already during the examination and counteract misinterpretation.

The Impact of Coating Defects on Water Transport in the Gas Diffusion Layer of PEM Fuel Cells

Present study suggests that the breakthrough pressure of a mixed-non-wetting (MNW) meniscus is highly sensitive to the extent of coating defects. On the other hand, the wetting meniscus breakthrough pressure showed little sensitivity to the geometry of the pore. Hydrophobic coatings such as PTFE are used to improve the water transport behaviour of the gas diffusion layer. Improved performance is typically associated with high breakthrough pressure, as evidenced by experiments. Simulations employing pores consider the influence of the pore geometry, and that of heterogeneous wetting and pinning conditions of the water droplets in contact with the GDL fibrous matrix. This model examines the water percolation behaviour at pore level, the pore being defined as a contact line of an evolving droplet in contact with fibers. In contrast with the pores of a pore-network model, the pore-level model captures the evolution of a liquid-gas interface having both pinned and free contact line segments. The mixed-non-wetting behaviour is caused by the hydrophobic coating which allows parts of the meniscus contact line to deform freely in contact with the fibers, while other parts of the meniscus remain pinned due to coating defects. The MNW meniscus is critical to establishing a high breakthrough pressure and a small characteristic droplet volume. The influence of the coating defects is simulated by MNW menisci having various ratios of pinned-to-free contact line segments.

The Impact of Coating Defects on Water Transport in the Gas Diffusion Layer of PEM Fuel Cells

Present study suggests that the breakthrough pressure of a mixed-non-wetting (MNW) meniscus is highly sensitive to the extent of coating defects. On the other hand, the wetting meniscus breakthrough pressure showed little sensitivity to the geometry of the pore. Hydrophobic coatings such as PTFE are used to improve the water transport behaviour of the gas diffusion layer. Improved performance is typically associated with high breakthrough pressure, as evidenced by experiments. Simulations employing pores consider the influence of the pore geometry, and that of heterogeneous wetting and pinning conditions of the water droplets in contact with the GDL fibrous matrix. This model examines the water percolation behavior at pore level, the pore being defined as a contact line of an evolving droplet in contact with fibers. In contrast with the pores of a pore-network model, the pore-level model captures the evolution of a liquid-gas interface having both pinned and free contact line segments. The mixed-non-wetting behaviour is caused by the hydrophobic coating which allows parts of the meniscus contact line to deform freely in contact with the fibers, while other parts of the meniscus remain pinned due to coating defects. The MNW meniscus is critical to establishing a high breakthrough pressure and a small characteristic droplet volume. The influence of the coating defects is simulated by MNW menisci having various ratios of pinned-to-free contact line segments.

A Lateral-Response Analyzed Model for Piles in Sloping Ground Considering Vertical Resistance Based on Transfer Matrix Method

In order to analyze the lateral response of piles subjected to combinational loads located at sloping ground, a simplified physical model is proposed and developed based on the Timoshenko beam theory and tri-parameter elastic foundation beam model. In this model, the effects of vertical resistance, shear deformation and initial inclination of pile shafts are taken into account, and the semi-analytical solution to the lateral behavior of pile is obtained by utilizing the transfer matrix approach. Specifically, the relative transfer matrix coefficients in the free, passive, and active segment of the pile are analytically determined through Laplace transformation. In addition, the validation of this model is conducted by comparing with field observations and predictions obtained from other existing methods. Moreover, the influences of initial inclination angle, vertical resistance in passive segments and the vertical load on the lateral response of the pile are also discussed in depth. The results indicate that, although there is a significant reduction effect emerged in both the lateral displacement and bending moment with the increase in the vertical resistance, a growth trend for those responses can be obtained with an increase in the initial inclination angle and vertical load.

Research on influence of anchor cable failure on slope dynamic response

Anchor cables are an important branch of geotechnical engineering and are widely used in slope reinforcement. The Wenchuan earthquake showed that the anchor cable fracture can cause the instability of the slope. The anchor cables in the numerical software obey the ideal elastic-plastic law and cannot simulate fracture and failure. To achieve the fracture effect, the anchor cable model is modified. Based on stepped slopes, the dynamic response characteristics are analyzed, and the effect of pre-tension is discussed. The results show that: 1) The influence of anchor cable failure on slope safety cannot be ignored. After the failure conditions are met, the free segment no longer transmits tension, and the anchored segment degenerates into soil nails. 2) When the slope is unstable, the anchor cable will show a continuous fracture phenomenon. The fracture first occurred in the dangerous parts such as the slope toe, and then turned to the top. 3) The fracture of the anchor cable will lead to the release of the soil stress, accompanied by the change of the acceleration amplitude and frequency, and finally manifested as a larger residual displacement. Slope reinforcement not only needs to consider the anchoring force, but also the coordination relationship.

The Value of Semantics in Food and Wine Labeling: Research on Italian Wine Consumers

Semantics studies have been experiencing an ever-growing utilization and application in packaging, product labeling and, more broadly, in marketing strategies. Considering the food and wine sector, existing research on semantics application in labeling confirms its worth in influencing consumers’ perception of products. In this sense, it is a fundamental tool for managers to communicate the value of their brands. Nevertheless, further studies are still needed to understand how the visual aspects of the packaging generate the desired meanings among consumers, especially in Italy. The paper intends to fill this gap by applying a semiotic approach to study Italian wine consumers. Specifically, a close-ended questionnaire, with a free word association segment focused on the values perceived by consumers when looking at four digitally crafted wine bottle front labels, was utilized. Although the results show some discrepancies from current studies, this paper points out that the existing literature on the topic seems comprehensively applicable to Italian consumers. However, given the exploratory nature of the study, it would be necessary to extend the number of respondents to further validate the results obtained.

Stretchable Self-Healing Plastic Polyurethane with Super-High Modulus by Local Phase-Lock Strategy.

In this work, a multiblock polyurethane (PU-Im) consisting of polyether and polyurethane segments with imidazole dangling groups is demonstrated, which can further coordinate with Ni2+ . By controlling the ligand content and metal-ligand stoichiometry ratio, PU-Im-Ni complex with vastly different mechanical behavior can be obtained. The elastomer PU-2Im-Ni has extraordinary mechanical strength (61MPa)andexcellenttoughness(420 MJ m-3 ), but the plastic PU-4Im-Ni exhibits super-high modulus (515 MPa),strength(63 MPa),andgoodstretchability(≈800%). The metal-ligand interaction between polyurethane segments and Ni2+ is proved by Raman spectra, dynamic mechanical analysis (DMA), and transmission electron microscopy (TEM). The polyurethane segments domain formed by microphase separation is dynamically "locked" by Ni2+ coordinated with imidazole, revealing a local phase-lock effect. The phase-locking hard domains reinforce the PU-Im-Ni complex and maintain stimuli-responsive self-healing ability, while the free polyether segments provide stretchability. Primarily, the water environment with plasticization effect serves as an effective and eco-friendly self-healing approach for PU-Im-Ni plastic. With the excellent mechanical performance, thermal/aquatic self-healing ability, and unique damping properties, the PU-Im-Ni complexes show potential applications in self-healing engineering plastic and cushion protection fields.

Damping ratio identification using attenuation responses extracted by time series semantic segmentation

Damping ratio is an essential dynamic characteristic of bridge structures, and its properties have still not been well understood due to the difficulties in accurate calculation with structural health monitoring (SHM) data. It is widely accepted that the exponential attenuation (EA) method using free attenuation responses is a reliable way to calculate damping ratio. To identify the damping ratio from SHM data with EA method, a time series semantic segmentation method is proposed in this paper to extract free attenuation segments from the massive data of monitored acceleration responses. A labeled semantic dataset is firstly constructed based on the long-term monitoring data of the Z24 bridge which is a continuous bridge widely used as a benchmark model for SHM, and the labeling standard is introduced to illustrate the preference of selecting desirable attenuation segments. Then an adapted U-net model is developed and trained with the constructed dataset, and key hyper-parameters including the configuration of convolutional kernel and decision boundary are investigated and determined to meet the requirement of processing time series data of acceleration responses. A large number of attenuation segments have then been extracted by the well-trained model, based on which the damping ratio of the 1st vibration mode in 10 months is obtained with the EA method. The identified damping ratios are found reliable as compared with those identified by the stochastic subspace identification method, thus enabling further investigation of the properties of damping ratio. Finally, the influence of the temperature variation is explored, revealing an obvious correlation relationship between the temperature and the damping ratio. The results of this study not only provide a novel method to calculate damping ratio with SHM data but also could deepen the understanding of damping ratio properties and serve as a reference for more reasonable utilization of the damping ratio in structural dynamic analysis or condition assessment.

Learning Needs Assessment of Multidisciplinary Staff Working Within the Memory Assessment Services – Survey Study

AimsTo assess the learning needs of the memory team multidisciplinary (MDT) staff working in South East Wales, in relation to diagnosis of dementia, types of dementia, anti-dementia medications and risk associated with dementia.MethodsAn online anonymised survey was designed and distributed via email among memory team MDT staff of 3 different health boards of the South East Wales area which included Aneurin Bevan University Health Board, Cwm Taf Morgannwg University Health Board and Cardiff and Vale University Health Board.The survey was designed to gather information about their understanding of the common type of dementia, treatment with medication, indications and cautions related to medications, the potential side effects and risks associated with Dementia. The survey had a mixture of `Likert Scale` format with free text segments where their opinion was sought in their own words.ResultsTwenty-one (21) staff members responded to the survey. The majority (16) were psychiatric nurses, rest were psychologists and support workers.Thirteen (13) staff members reported they feel confident in identifying subtypes of dementia whereas the rest reported they can benefit from additional knowledge. Majority of staff felt they understood the indications of anti-dementia medication side effects of medications and risks associated with Dementia but do not fully understand the contra-indications and cautions related to anti-dementia medications.Participants suggested that regular teaching, lectures and updates should be arranged especially targeting the diagnostic criteria, medication and risk assessment. Sessions providing bite-size information on a regular basis to build on their knowledge base were suggested.Participants also suggested shadowing doctors and consultants in memory clinics as a useful tool to improve their knowledge base.ConclusionMDT staff working with memory teams are at the front line of screening, assessments and providing help and treatment to patients and their families. It is important to make sure our staff are equipped with evidence-based accurate knowledge and training.This survey study indicated that MDT staff working within the memory team appreciate more training and helped identify the specific areas and mode of teaching required.Prescription of medication may be seen as a doctor's responsibility but we need to ensure our MDT staff has up to date knowledge of types of medications used, their indications, contra-indications, monitoring requirements, and side effects.Regular teaching, online modules and experience of shadowing with doctor's clinics should be offered to all the MDT staff.

Reverse blood flow as an option in mandibular reconstruction using a two-segment fibula free flap

Microsurgical reconstruction is currently considered a method of choice for the repair of soft tissue or bony defects in head and neck surgery. This technical note presents the use of a reverse flow technique in mandibular reconstruction with two segments of fibula free flap in a patient with bilateral pseudoarthrosis. In the standard procedure, both segments of the fibula are supplied by one donor vascular pedicle with normal antegrade blood flow. The approach presented here employs reverse flow in the distal segment of the fibula using a venous graft to create two vascular independent free fibula segments. Reverse flow in mandibular reconstruction represents an alternative option to support the success of microsurgical procedures in indicated cases.

Coprime Ehrhart Theory and Counting Free Segments

Abstract A lattice polytope is free (or empty) if its vertices are the only lattice points it contains. In the context of valuation theory, Klain [16] proposed to study the functions $\alpha _i(P;n)$ that count the number of free polytopes in $nP$ with $i$ vertices. For $i=1$, this is the famous Ehrhart polynomial; for $i&amp;gt; 3$, the computation is likely impossible; and for $i=2,3$ it is computationally challenging. In this paper, we develop a theory of coprime Ehrhart functions that count lattice points with relatively prime coordinates and use it to compute $\alpha _2(P;n)$ for unimodular simplices. We show that the coprime Ehrhart function can be explicitly determined from the Ehrhart polynomial and we give some applications to combinatorial counting.

Blending physiology and RNAseq to provide new insights into regulation of epithelial transport: switching between ion secretion and reabsorption.

This Review addresses the means by which epithelia change the direction of vectorial ion transport. Recent studies have revealed that insect Malpighian (renal) tubules can switch from secreting to reabsorbing K+. When the gut of larval lepidopterans is empty (during the moult cycle) or when the larvae are reared on K+-deficient diet, the distal ileac plexus segment of the tubule secretes K+ from the haemolymph into the tubule lumen. By contrast, in larvae reared on K+-rich diet, ions and fluid are reabsorbed from the rectal lumen into the perinephric space surrounding the cryptonephridial tubules of the rectal complex. Ions and fluid are then transported from the perinephric space into the lumen of the cryptonephridial tubules, thus supplying the free segments of the tubule downstream. Under these conditions, some of the K+ and water in the tubule lumen is reabsorbed across the cells of the distal ileac plexus, allowing for expansion of haemolymph volume in the rapidly growing larvae, as well as recycling of K+ and base equivalents. RNA sequencing data reveal large-scale changes in gene transcription that are associated with the switch between ion secretion and ion reabsorption by the distal ileac plexus. An unexpected finding is the presence of voltage-gated, ligand-gated and mechanosensitive ion channels, normally seen in excitable cells, in Malpighian tubules. Transcriptomic surveys indicate that these types of channels are also present in multiple other types of vertebrate and invertebrate epithelia, suggesting that they may play novel roles in epithelial cell signalling and regulation of epithelial ion transport.

Turning Point and Free Segments Strategies for Navigation of Wheeled Mobile Robot

The basic idea of the developed work is to solve the problem of mobile robot navigation with obstacle avoidance and the trajectory tracking problem in simple and complex environments. The research contribution aims to develop a strategy of navigation based on the turning point and the free segments algorithms. Indeed, a turning point method is developed in order to solve the problem of navigation in a simple environment. Then, the free segments approach is applied in order to solve the problem of obstacle avoidance in a complex environment. The second part of this paper aims to solve the problem of trajectory tracking. For this reason, a sliding mode controller is proposed as a solution to control the stability of the mobile robot. Finally, some simulation results which are developed using Matlab software are given to prove the validity of the developed work.

Structural studies of fibrinolysis: how to disassemble a clot

Fibrin is degraded by the fibrinolytic system wich a plasminogen activator converts plasminogen to plasmin, a serine protease that cleaves specific bonds in fibrin leading to solubilization. To elucidate the biophysical processes involved in conversion of insoluble fibers to soluble fragments, fibrin was treared with either plasmin or the combination of plasminogen and its activator, and morphologic changes were observed using scanning electron microscopy. Initial changes in the fibrin matrix included creation of many free fiber ends and gaps in the continuity of fibers. With more extensive digestion, free fiber segments associated laterally, resulting in formation of thick fiber handles. Supernatants of digesting clots, containing soluble derivatives, were negatively contrasted and examined by transmission electron microscopy large complex fragments containing portions of multiple fibers were observed, as were piaces of individual fibers and smaller fragments. Some large fragments had sharply defined ends, indicating that they had been cleaved perpendicularly to the fiber direction. Other fibers showed splayed ends or a lacy meshwork of surrounding protofibrils. Fibrinolysis was also followed by confocal microscopy of plasma clots labeled with colloidal gold, so that changes at the lysis front of hydrated clots could be examined in real time. Clots made up of thin fibers were cleaved more slowly than clots made up of thick fibers, even though individual thin fibers were cleaved more rapidly. These results indicate that fibrinolytic degradation results in larger pieces than previously identified, and that plasmin digestion proceeds locally by transverse cutting across fibers rather than by progressive cleavage uniformly around the fiber. A model is proposed for the crawling of plasmin across fibrin fibers.