Microscopic Variables Research Articles

Skin graft associated with platelet-rich plasma in correcting extensive injuries resulting from the resection of skin cancer chemically induced in rats.

ABSTRACTPurpose:To evaluate whether using platelet-rich plasma (PRP) in the graft recipient bed after the resection of a neoplasia can influence its recurrence because this product stimulates angiogenesis, mitogenesis and chemotaxis.Methods:A study with 30 rats Wistar (Rattus norvegicus albinus), which were separated into group A (induction of carcinogenesis, PRP in the postoperative period) and group B (induction of carcinogenesis, absence of PRP in the postoperative period), with 15 animals in each. Carcinogenesis was induced on the skin of the animals’ chest by the topical application of 0.5% dimethylbenzantracene (DMBA) diluted in acetone. After surgical resection of the induced neoplasia, PRP was used to stimulate angiogenesis before surgical wound synthesis. Data on the control and experimental groups and macroscopic and microscopic variables were evaluated using analysis of variance and the Tukey’s test (5%).Results:It was possible to determine that the use of PRP is good in reconstructive surgeries, but it is contraindicated in patients during tumor resection, as it can cause changes in the surgical bed, in addition to stimulating recurrences and metastases.Conclusions:PRP may interact with tumour cells that were in the recipient site of the surgical wound during the resection of a neoplasia, and a local recurrence process can be triggered by applying this product.

Seasonal variations of male reproductive parameters of Tomodon dorsatus from Southeastern Brazil

ABSTRACT: The morphology of the male reproductive tract of Tomodon dorsatus was described in the austral seasons of the year considering macroscopic and microscopic variables. For this purpose, 56 specimens from the herpetological collection of the “Instituto Butantan” were used. Fragments of the testes, kidneys and ductus deferens were collected and submitted to histological routine. The peak of the testicular volume was observed in the summer and the epithelium of the seminiferous tubules had higher height in the summer (p=0.001). The testes were active throughout the year, however, the spermiogenesis peaked in the summer. There were spermatozoa in the lumen of the ductus deferens in all seasons of the year. Renal length was higher in autumn (p=0.027), and renal width did not show a significant increase (p=0.237). The diameter and epithelial height of the sexual segment of the kidney (SSK) showed hypertrophy in winter and spring, coinciding with the mating period. Based on findings of this study, we can suggest that, at the population level, the reproductive cycle of T. dorsatus can be considered seasonal semi-synchronous, due to the peak of spermiogenic activity in the hot season, and discontinuous at the individual level.

Polynomial functions for configurational correlation functions in Gibbs energies of solid solutions using cluster variation method

The cluster expansion – cluster variation methods (CE – CVM) offer a reliable framework to obtain short range order information for the chosen configurational state of a system accurate up to the basic cluster chosen in terms of the microscopic state variables called correlation functions (CFs). The calculation of the CFs involves solving a set of nonlinear equilibrium equations using compute intensive numerical methods. In this paper a method is presented to approximate the equilibrium values of CFs as polynomial functions of composition which eliminate the necessity of solving equilibrium equations. The coefficients of these polynomials are expressed as rational functions of temperature and system specific energy parameters. This method is comparable to standard CALPHAD methods in its ease of application without sacrificing information about short range order in the system.This procedure is applied to an A2–B32 system using tetrahedron approximation for the case of exclusive second neighbour pair interactions. These polynomials yield CFs comparable to those obtained from numerical solutions in the usual ranges of energy parameters and temperatures.

Von Karman spatial correlation functions for modeling ultrasonic scattering in metallic media

In recent years, ultrasonic scattering has been studied as a potential method for nondestructive microstructure characterization in polycrystalline media. In order to invert microstructural data from ultrasonic data, analytical models of wave propagation and material statistics are generally employed. The microstructure statistics are frequently represented by spatial correlation functions (SCFs), which describe how microscopic variables at random positions are correlated (e.g., elastic stiffness). In polycrystalline media with statistically isometric crystallites, SCFs are defined as the probability that two randomly chosen points lie within a single crystallite (or grain). This work evaluates the suitability of common forms of the SCF in capturing the statistics of realistic microstructures in the context of ultrasonic scattering measurements. In addition, we introduce the von Karman SCF, frequently used in seismic wave propagation studies, as a potential alternative for metallic components with increased microstructural complexity. In the macroscale, the material systems are assumed to be statistically isotropic, and the microstructural differences focus on the morphology of the grain structure.

Risk Factors for Malignant Transformation of Squamous Intraepithelial Lesions

Squamous intraepithelial lesions (SIL) are persistent white and white-red lesions that may represent precursor lesions for invasive squamous cell carcinoma (SCC). SILs encompass epithelial hyperplasia/hyperkeratosis, dysplasia, and carcinoma in situ. Specific indicators within SILs would be helpful for risk determination and treatment decisions. The purpose of this study was to determine the risk of SIL transformation to SCC using clinical appearance, histology, and immunohistochemical staining of biomarkers. A retrospective cohort study was conducted of patients diagnosed with oral cavity SILs between 2002 and 2012. Subjects were identified using billing records and pathology reports. Subjects were included if they had a new diagnosis of SIL via biopsy, histologic blocks/slides available for review, and > 5 years of follow-up after biopsy. Subjects with an existing or previous diagnosis of SCC at time of SIL diagnosis were excluded. Subjects were divided into two groups: 1) Those with SILs who did not transform to SCC and 2) those who transformed. Predictor variables included demographics (gender, age) and medical history (history of tobacco, alcohol, betel nut use, immune status, history of radiation). Macroscopic lesion related variables were site, size, and clinical appearance (described as white, red, heterogenous red-white, ulcerated, or nodular). Microscopic lesion variables were severity of dysplasia, location of atypia within epithelium (lower one-third, lower two-third, or full thickness), mitotic index, and amount of apoptosis, nuclear pleomorphism, rete peg complexity, lichenoid chronic inflammation, and hyperkeratosis. Mitotic index was quantified as the number of mitotically active cells recorded per high-powered field (hpf, 400x). Apoptotic abundance, nuclear pleomorphism, and rete-peg complexity were graded on a semi-quantitative scale 1-5. Lichenoid inflammation and hyperkeratosis were assessed as present or absent. Immunohistochemical lesion variables were p53 and Ki-67 immunoreactivity and measured as amount of positively stained cells per hpf. The primary outcome variable was presence of SCC on a subsequent biopsy (i.e., transformation to SCC). All diagnostic slides were reviewed and rated by a head and neck pathologist (WCF). Statistical results were analyzed using a Chi2 test, Fisher exact test, and 2-tailed t-test. Statistical results were considered significant with a 95% confidence interval if they had a P-value less than .05. A total of 60 subjects (45%, 27 female) were included of which 38 (63%, 17 female) did not transform to SCC whereas 22 (37%, 10 female) transformed. Mean ages of groups 1 and 2 were 58.2 ± 12.0 and 63.1 ± 15.1 years, respectively (P = .202). There were no differences in medical history and lesion location. Mean size of the SIL in groups 1 and 2 was 234 mm2 and 228 mm2, respectively, (P = .957). Transformation was significantly higher for heterogeneous red/white lesions: 5 (13%) in group 1, 9 patients (42%) in group 2 (P = .014). Patients with severe dysplasia were more likely to transform with 10 in group 2 (45.5%) and 2 in group 1 (5.3%) [P = .0003]. Atypia limited to the lower one-third was less likely to transform (P = .0173). Increased apoptosis (P = .043) and rete peg complexity (P = .014) were associated with SCC transformation. There was no difference in immunohistochemical staining of Ki-67 between groups (P = .305). In conclusion, SILs that transformed to SCC were more likely to have a red-white appearance, severe dysplasia, atypia throughout the epithelium, greater apoptosis, and rete peg complexity. Ki-67 immunoreactivity was not associated with transformation. Ongoing evaluation of p53 will be reported. The presence of these factors may influence decision to excise a SIL vs surveillance.

Microscopic insight to specificity of metal ion cofactor in DNA cleavage by restriction endonuclease EcoRV.

Restriction endonucleases protect bacterial cells against bacteriophage infection by cleaving the incoming foreign DNA into fragments. In presence of Mg2+ ions, EcoRV is able to cleave the DNA but not in presence of Ca2+ , although the protein binds to DNA in presence of both metal ions. We make an attempt to understand this difference using conformational thermodynamics. We calculate the changes in conformational free energy and entropy of conformational degrees of freedom, like DNA base pair steps and dihedral angles of protein residues in Mg2+ (A)-EcoRV-DNA complex compared to Ca2+ (S)-EcoRV-DNA complex using all-atom molecular dynamics (MD) trajectories of the complexes. We find that despite conformational stability and order in both complexes, the individual degrees of freedom behave differently in the presence of two different metal ions. The base pairs in cleavage region are highly disordered in Ca2+ (S)-EcoRV-DNA compared to Mg2+ (A)-EcoRV-DNA. One of the acidic residues ASP90, coordinating to the metal ion in the vicinity of the cleavage site, is conformationally destabilized and disordered, while basic residue LYS92 gets conformational stability and order in Ca2+ (S) bound complex than in Mg2+ (A) bound complex. The enhanced fluctuations hinder placement of the metal ion in the vicinity of the scissile phosphate of DNA. Similar loss of conformational stability and order in the cleavage region is observed by the replacement of the metal ion. Considering the placement of the metal ion near scissile phosphate as requirement for cleavage action, our results suggest that the changes in conformational stability and order of the base pair steps and the protein residues lead to cofactor sensitivity of the enzyme. Our method based on fluctuations of microscopic conformational variables can be applied to understand enzyme activities in other protein-DNA systems.

Avaliação do alongamento passivo e da eletroestimulação sobre a plasticidade muscular

Objetivo: Avaliar e comparar efeitos macro e microscópicos das terapias de alongamento e eletroestimulação sobre o tecido muscular após imobilização. Métodos: Utilizados 25 ratos (Rattus norvegicus albinus, linhagem wistar) machos adultos, sadios, divididos aleatoriamente em cinco grupos (n=5). Foram imobilizados por 7 dias, depois receberam 10 sessões de alongamento passivo e eletroestimulação muscular, de forma isolada e combinada, no músculo tibial anterior direito, que após foi extraído para análise. Variáveis macroscópicas: massa e comprimento total do músculo, variáveis microscópicas: número de sarcômeros em série e tecido conjuntivo. Dados analisados de forma cega, armazenados e tratados por estatística descritiva através do Software Bioestatic 5.3. Resultados: Massa muscular: não se observou ganho sobrepujante à perda pela imobilização, mas conteve-se perda maior com a utilização da eletroestimulação de forma isolada. Número de sarcômeros em série: alongamento e eletroestimulação foram eficientes para o aumento, a combinação das terapias não interferiu negativamente no tratamento. Comprimento do músculo e quantidade de tecido conjuntivo depositado no meio intramuscular: resultados estatísticos insignificantes. Conclusão: Eletroestimulação é mais eficiente em conter a perda de massa muscular, ambas técnicas de forma isolada são benéficas para aumento do número de sarcômeros.

A unified depth-averaged approach for integrated modeling of surface and subsurface flow systems

A two-dimensional depth-averaged continuum framework is developed for simulating the interaction of flows outside and within porous media. A unique set of generalized equations applicable to both surface and subsurface systems is derived originating from conservation laws of microscopic variables with first volume-averaging and then integrating vertically. The model is free of ad-hoc coupling as interface conditions are satisfied implicitly owing to the generalized nature of the governing equations. The set of depth-integrated equations (unconditionally hyperbolic) is resolved by employing a Total-Variation-Diminishing MacCormack scheme. The developed model is validated with four one-dimensional experimental test-cases (containing both Darcy and non-Darcy regimes) and applied to a demonstrative two-dimensional scenario having various interface conditions. Results obtained from the proposed framework highlights the potential applicability of the generalized model for diverse time-scales and vertical/ sloping interface conditions.

META Score: An International Consensus Scoring System on Mesh-Tissue Adhesions.

Currently, the lack of consensus on postoperative mesh-tissue adhesion scoring leads to incomparable scientific results. The aim of this study was to develop an adhesion score recognized by experts in the field of hernia surgery. Authors of three or more previously published articles on both mesh-tissue adhesion scores and postoperative adhesions were marked as experts. They were queried on seven items using a modified Delphi method. The items concerned the utility of adhesion scoring models, the appropriateness of macroscopic and microscopic variables, the range and use of composite scores or subscores, adhesion-related complications and follow-up length. This study comprised two questionnaire-based rounds and one consensus meeting. The first round was completed by 23 experts (82%), the second round by 18 experts (64%). Of those 18 experts, ten were able to participate in the final consensus meeting and all approved the final proposal. From a total of 158 items, consensus was reached on 90 items. The amount of mesh surface covered with adhesions, tenacity and thickness of adhesions and organ involvement was concluded to be a minimal set of variables to be communicated separately in each future study on mesh adhesions. The MEsh Tissue Adhesion scoring system is the first consensus-based scoring system with a wide backing of renowned experts and can be used to assess mesh-related adhesions. By including this minimal set of variables in future research interstudy comparability and objectivity can be increased and eventually linked to clinically relevant outcomes.

An asymptotic preserving unified gas kinetic particle method for radiative transfer equations

In this work, we propose a unified gas kinetic particle (UGKP) method for solving the nonlinear thermal radiative transfer equations. The UGKP method is a multiscale method in that the macro and microscopic variables are coupled and updated in a consistent way. It employs a finite volume formulation for the macroscopic variable evolution, and a particle-based Monte Carlo solver for tracking the non-equilibrium transport. The stiff coupling between the radiation and material energy is included and resolved efficiently by the coupled macroscopic equations. Compared with the implicit Monte Carlo (IMC) method, it does not employ the effective scattering events. Moreover, we demonstrate that the UGKP method has the asymptotic preserving property in capturing the diffusion limit in optically thick regions. Numerical simulations show that our method is comparable in computational cost to the IMC method for optically thin problems, and becomes much more efficient for optically thick problems. More importantly, the UGKP method doesn't require the cell size being less than the photon's mean free path and it achieves the highest efficiency in the optically thin and thick regions self-adaptively.

A macroscopic traffic flow model considering the velocity difference between adjacent vehicles on uphill and downhill slopes

In this paper, we deduced a macroscopic traffic model on the uphill and downhill slopes by employing the transformation relation from microscopic variables to macroscopic ones based on a microscopic car-following model considering the velocity difference between adjacent vehicles. The angle [Formula: see text] of the uphill and downhill and the gravitational force have a great impact upon the stability of traffic flow. The linear stability analysis for macroscopic traffic model yielded the stability condition. The Korteweg–de Vries (KdV) equation is derived by nonlinear analysis and the corresponding solution to the density wave near the neutral stability line is obtained. By using the upwind finite difference scheme for simulation, the spatiotemporal evolution patterns of traffic flow on the uphill and downhill are attained. The unstable region is shrunken with slope of the gradient increasing and backward-traveling density waves gradually decrease and even disappear on uphill. Conversely, the unstable region on downhill is extended and density waves propagate quickly backward to the whole road with slope of the gradient increasing.

Field-Dependent Ionic Conductivities from Generalized Fluctuation-Dissipation Relations.

We derive a relationship for the electric field dependent ionic conductivity in terms of fluctuations of time integrated microscopic variables. We demonstrate this formalism with molecular dynamics simulations of solutions of differing ionic strength with implicit solvent conditions and molten salts. These calculations are aided by a novel nonequilibrium statistical reweighting scheme that allows for the conductivity to be computed as a continuous function of the applied field. In strong electrolytes, we find the fluctuations of the ionic current are Gaussian, and subsequently, the conductivity is constant with applied field. In weaker electrolytes and molten salts, we find the fluctuations of the ionic current are strongly non-Gaussian, and the conductivity increases with applied field. This nonlinear behavior, known phenomenologically for dilute electrolytes as the Onsager-Wien effect, is general and results from the suppression of ionic correlations at large applied fields, as we elucidate through both dynamic and static correlations within nonequilibrium steady states.

A New Continuum Model considering Driving Behaviors and Electronic Throttle Effect on a Gradient Highway

In order to explore the potential impact of sloping road on traffic flow, an improved car-following model considering electronic throttle (ET) dynamics and driver’s driving characteristics on slope is proposed. Based on the improved car-following model, a new continuum model is established through the conversion relationship between microscopic variables and macroscopic variables. Firstly, the stability condition of the model is obtained by using the linear stability theory, after that the evolution process of traffic flow density wave near the neutral stability curve is studied by using the nonlinear analysis method, and we also get the improved KdV-Burgers equation. At the same time, numerical experiments and experimental verification of the model are carried out; the theoretical analysis and numerical results show that the ET effect and aggressive driving of drivers play an important role in alleviating traffic congestion to a certain extent.

Corneal endothelial assessment in xeroderma pigmentosum: a case-control study.

To analyze and compare corneal endothelial mosaic in terms of endothelial cell population, morphology and irregularity in patients with xeroderma pigmentosum (XP) with clear corneas with normal age and sex matched subjects using specular microscopy. Nine patients with XP without corneal involvement were evaluated in the study. An age and sex matched group of nine healthy subjects participated as control group. Evaluation of corneal endothelial layer was performed using specular microscopy. Each study group consisted of five males and four females with total mean age of 28 ± 11.3years (12-46years). Endothelial cell density was significantly lower in patients with XP in comparison with controls (P < 0.002). Maximum and minimum cell areas were significantly higher in XP group (P < 0.016 and P < 0.029, respectively). Although central corneal thickness was higher in controls, the difference was not statistically significant (P = 0.106). Furthermore, our study showed that the patients with XP had no difference with controls in terms of coefficient of variation of cell areas. This study showed that endothelial cell population can decrease in patients with XP, although other specular microscopic variables such as coefficient of variation and central corneal thickness may remain within normal values.

Towards a controllability analysis of multiscale systems: Application of the set-theoretic approach to a semi-batch emulsion polymerization process

This work presents a framework to evaluating the controllability of multiscale systems based on a set-theoretic approach. Calculation of the Controllable Trajectories Set is the core of the set-theoretic approach. From a multi-scale perspective, such calculation is a computationally- intractable problem. Therefore, to overcome the intrinsic curse of dimensionality of the problem, Variance Algebra concepts and a statistical modeling approach are combined to obtain a closed-form allowing to perform an output-controllability analysis for a multiscale system. A semi-batch emulsion polymerization process is adopted as a case study. Results have shown that both, the final Particle Size Distribution (mesoscopic variable) and the secondary particle nucleation rate (microscopic variable) are output-controllable. Evaluating the controllability of lower-scale variables (i.e. below macroscopic) could mitigate the dependency of the current control strategies of on-line measurements at the lower scales as well as help to better understand the process capabilities of achieving the desired product quality specifications.

The Physicomechanical Deterioration Characteristics and Mesoscopic Damage Analysis of Sandstone under Acidic Environment

The physicomechanical deterioration characteristics of sandstone subjected to H2SO4, HCl, and H2O solutions of different pH values are studied by the method of long‐term accelerated immersion. The quantitative relationships between the damage variables based on CT (computer tomographic identification technology) numbers and the immersion time, the uniaxial compressive strength, the peak point strain, and the elastic modulus of rock samples are analyzed. The test results indicate that the pH value of immersion solutions, the dissolution rate of Ca2+ and Na+, and the quality change of rock samples show visible stage characteristics under acidic environment. With the soaking time extended, the pH value of solutions increases gradually, and the quality change of rock samples decreases gradually. The smaller the pH value of immersion solutions is, the higher the dissolution rate of Ca2+ and Na+ is. However, the cation dissolution rate under a weak acid environment with a high pH value has little difference with that under the distilled water (pH = 7). With the increase of the soaking time and the acidity, the compaction stage of rock samples becomes longer, the elastic stage becomes shorter, the deterioration degree of mechanical parameters becomes more extensive, and the destruction of sandstone samples shows ductility characteristics increasingly. The corrosion degree of corroded sandstone samples is quantitatively represented by microscopic damage variables based on CT numbers. The regression analysis results show that damage variables of acid‐corroded sandstone samples have a power function relationship with soaking time and an exponential function relationship with peak strength, peak point strain, and elastic modulus.

Prediction of Discharge Performances of Pseudocapacitors Using Their Impedance Characteristics

A first principle model was used to fit the impedance data of intrinsic pseudocapacitors based on polypyrrole and manganese dioxide electrodes and was validated by successfully predicting charge/discharge characteristics. The model performs non-linear regression to an electrochemical impedance spectroscopy (EIS) data using a rigorous prototypical model of pseudocapacitance, which emphasizes an integrated description of the various components of the capacitor at the microscopic and macroscopic level. Parametric studies showcase further how important microscopic variables in pseudocapacitors influence both impedance spectra and galvanostatic discharge.

Estimation of microscopic variables for materials system optimization using Cluster Variation Method

Stability of various phases present in the alloy system under thermodynamic conditions of temperature and composition estimated through experiments requires enormous number of tests and huge manpower. The study of these phases required equilibrium diagrams developed from experimental data. These diagrams are road maps for understanding structural stability of materials system under prevailed service conditions. Development of sound thermodynamic model is essential requirement to reduce the experimental cost, effort and time. Therefore theoretical computation of phase stability in materials system reduces the experimental burden. Although various thermodynamic models such as CALPHAD etc. are developed and using for estimating the materials systems, a reliable and versatile physical based thermodynamic model is the requirement in current day materials system development. Cluster Variation Method (CVM) is one such familiar model but algebraically complex to implement. Therefore the immediate task required to attempt is to reduce the algebraic complexity of the model by devising some simplified procedures for estimating materials systems using CVM. In the proposed work, procedures have been devised in order to reduce the algebraic complexity of Cluster Variation Method and make it viable for computation of materials systems. In the process of developing these procedures one of the important task is to estimate initial guess of microscopic variables for model materials system which is viable to carry out optimization of the materials system. As a part of these procedures this work estimates initial values of microscopic variables using which simultaneous optimization process can be carried successfully by developing procedures and approximating the proper initial guess values of these variables. A typical materials data has been selected to validate these procedures based on special features of phase diagrams like miscibility gap and congruent extreme etc. in this work.

Dynamic modification of cut marks by trampling: temporal assessment through the use of mixed-effect regressions and deep learning methods

Cut marks exposed to a short period of trampling were easily differentiated from trampling marks. Here, through the combined use of cross-validated logistic regression, mixed-effect regression models and computer vision deep learning methods, we approach the timing and modification rate of the microscopic variables that characterize cut marks. This study emphasizes the need to understand that bone surface modifications are dynamic taphonomic entities subjected to context-dependent morphing processes. Every depiction of a mark is just time-determined. Here, we show through experiments that trampling affected mostly the presence and internal configuration of microstriations, as well as the flaking and the morphology of the shoulder of the mark. The presence of overlapping striae and microabrasion were reported as signatures of trampling which did not affect cut mark morphology. Sandy sediment was found more abrasive than gravel sediment because of its potential to get inside the grooves of marks and modify their walls more intensively. The moderate abrasion process modeled here did not impact cut marks to the point of not being differentiated from other types of marks. A comparison with trampling marks successfully classified both types of modifications.

On the Statistical Mechanics of Life: Schrödinger Revisited

We study the statistical underpinnings of life, in particular its increase in order and complexity over evolutionary time. We question some common assumptions about the thermodynamics of life. We recall that contrary to widespread belief, even in a closed system entropy growth can accompany an increase in macroscopic order. We view metabolism in living things as microscopic variables directly driven by the second law of thermodynamics, while viewing the macroscopic variables of structure, complexity and homeostasis as mechanisms that are entropically favored because they open channels for entropy to grow via metabolism. This perspective reverses the conventional relation between structure and metabolism, by emphasizing the role of structure for metabolism rather than the converse. Structure extends in time, preserving information along generations, particularly in the genetic code, but also in human culture. We argue that increasing complexity is an inevitable tendency for systems with these dynamics and explain this with the notion of metastable states, which are enclosed regions of the phase-space that we call “bubbles,” and channels between these, which are discovered by random motion of the system. We consider that more complex systems inhabit larger bubbles (have more available states), and also that larger bubbles are more easily entered and less easily exited than small bubbles. The result is that the system entropically wanders into ever-larger bubbles in the foamy phase space, becoming more complex over time. This formulation makes intuitive why the increase in order/complexity over time is often stepwise and sometimes collapses catastrophically, as in biological extinction.