Values Of Λ1 Research Articles

Modeling spatial evolution of multi-drug resistance under drug environmental gradients.

Multi-drug combinations to treat bacterial populations are at the forefront of approaches for infection control and prevention of antibiotic resistance. Although the evolution of antibiotic resistance has been theoretically studied with mathematical population dynamics models, extensions to spatial dynamics remain rare in the literature, including in particular spatial evolution of multi-drug resistance. In this study, we propose a reaction-diffusion system that describes the multi-drug evolution of bacteria based on a drug-concentration rescaling approach. We show how the resistance to drugs in space, and the consequent adaptation of growth rate, is governed by a Price equation with diffusion, integrating features of drug interactions and collateral resistances or sensitivities to the drugs. We study spatial versions of the model where the distribution of drugs is homogeneous across space, and where the drugs vary environmentally in a piecewise-constant, linear and nonlinear manner. Although in many evolution models, per capita growth rate is a natural surrogate for fitness, in spatially-extended, potentially heterogeneous habitats, fitness is an emergent property that potentially reflects additional complexities, from boundary conditions to the specific spatial variation of growth rates. Applying concepts from perturbation theory and reaction-diffusion equations, we propose an analytical metric for characterization of average mutant fitness in the spatial system based on the principal eigenvalue of our linear problem, λ1. This enables an accurate translation from drug spatial gradients and mutant antibiotic susceptibility traits to the relative advantage of each mutant across the environment. Our approach allows one to predict the precise outcomes of selection among mutants over space, ultimately from comparing their λ1 values, which encode a critical interplay between growth functions, movement traits, habitat size and boundary conditions. Such mathematical understanding opens new avenues for multi-drug therapeutic optimization.

Investigating Vibration Characteristics of Cross-Laminated Timber Panels Made from Fast-Grown Plantation Eucalyptus nitens under Different Support Conditions

The mechanical properties of fibre-managed Eucalyptus nitens (E. nitens) cross-laminated timber (CLT) have previously been extensively studied, proving the material to be structurally safe and reliable. However, the vibration performance of CLT manufactured from this relative new construction species is not yet fully understood, especially under different support conditions. In this study, three types of support conditions, including roller–roller, bearer–bearer and clamp–bearer support conditions, were examined under vibration impulse-response testing performed using a simple but effective and repeatable excitation method consisting of a basketball dropped from a known height and an accelerometer. Six three-ply E. nitens CLT panels considered to have different moduli of elasticity in different layers and one strength-class C24 spruce CLT as a controlled reference were included in this study. The results suggest that the fundamental frequency values can effectively reflect the inherent characteristics of CLT panels (bending stiffness and density); however, no obvious relationship was observed between damping ratios and these inherent properties. The values of frequency constant λ1 were determined to analyse the effect of different support conditions on the values of fundamental frequency. The average values of λ1 for the roller–roller (9.6) and bearer–bearer (10.1) supports align with the theoretical values (9.87) for simply support (S-S) conditions. However, when clamping loads were applied at one edge of the bearer support, the average values of λ1 increased up to 10.8 but remained far below the theoretical values for clamped–pinned (C-S) support (15.4).

The Effects of Cooling Rate on Microstructure Formation during Solidification of 319 Alloy

This work assesses the effect of cooling rate (T˙\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\dot{T}$$\\end{document}) on the solidification kinetics and microstructural evolution of a 319 aluminum alloy with and without the addition of Al–5 wt%Ti–1wt%B grain refiner. Directionally solidified samples were produced under various cooling rates (from 0.05 to 40 °C/s). Microstructure coarsening was then quantitatively analyzed by measuring grain size (GS) and primary (λ1), secondary (λ2) and average (λL) dendrite arm spacing. The results show that polarized optical images can be used to identify dendrite fragments between neighboring primary dendrites, allowing a more accurate microstructural analysis after the addition of grain refiner. The results also show that, for a given T˙\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\dot{T}$$\\end{document}, although GS is reduced after the addition of grain refiner, the respective values of λ1, λ2 and λL remain practically the same. In other words, the grain refiner only affects nucleation and not grain growth. Experimental growth equations are proposed to represent this behavior. Furthermore, λL is shown to be a good parameter for evaluating microstructural refinement.

Pattern-Multiplicative Average of Nonnegative Matrices Revisited: Eigenvalue Approximation Is the Best of Versatile Optimization Tools

Given several nonnegative matrices with a single pattern of allocation among their zero/nonzero elements, the average matrix should have the same pattern, too. This is the first tenet of the pattern-multiplicative average (PMA) concept, while the second one suggests the multiplicative (or geometric) nature of averaging. The original concept of PMA was motivated by the practice of matrix population models as a tool to assess the population viability from long-term monitoring data. The task has reduced to searching for an approximate solution to an overdetermined system of polynomial equations for unknown elements of the average matrix (G), and hence to a nonlinear constrained minimization problem for the matrix norm. Former practical solutions faced certain technical problems, which required sophisticated algorithms but returned acceptable estimates. Now, we formulate (for the first time in ecological modeling and nonnegative matrix theory) the PMA problem as an eigenvalue approximation one and reduce it to a standard problem of linear programing (LP). The basic equation of averaging also determines the exact value of λ1(G), the dominant eigenvalue of matrix G, and the corresponding eigenvector. These are bound by the well-known linear equations, which enable an LP formulation of the former nonlinear problem. The LP approach is realized for 13 fixed-pattern matrices gained in a case study of Androsace albana, an alpine short-lived perennial, monitored on permanent plots over 14 years. A standard software routine reveals the unique exact solution, rather than an approximate one, to the PMA problem, which turns the LP approach into ‘’the best of versatile optimization tools”. The exact solution turns out to be peculiar in reaching zero bounds for certain nonnegative entries of G, which deserves modified problem formulation separating the lower bounds from zero.

Diffusion tensor magnetic resonance imaging in differentiation of breast lesions

BackgroundDiffusion tensor imaging (DTI) is a novel approach which uses extra gradients to quantify diffusion in several directions (at least six). The purpose of this research was to determine the role of diffusion tensor magnetic resonance imaging in breast lesion differentiation.ResultsApparent diffusion coefficient (ADC) values were significantly lower in malignant than benign lesions, with a cut-off value of 1.21 × 10−3 mm2/s, this gives a sensitivity of 88.46%, specificity 87.50% and accuracy 86.7%. Values of fractional anisotropy (FA) were higher significantly in malignant compared to benign lesions with a 0.15 cut-off value, has a 95.83% sensitivity, 96.15% specificity, and 95.6%, accuracy. Values of RA were significantly higher in malignant (0.180 ± 0.068) compared to benign lesions, with 0.13 cut-off value. Sensitivity, specificity, and accuracy were, respectively, 91.69%, 92.31%, and 90.2%. Values of λ1 were significantly lower in malignant (1.4 ± 0.453 × 10−3 mm2/s) than in benign (2.19 ± 0.659 × 10−3 mm2/s) lesions with a cut-off value of 1.71 × 10−3 mm2/s. Sensitivity and specificity were, respectively, 95.83 and 96.15%. The combined evaluation by (dynamic contrast enhancement) Sensitivity improved to 100% with DCE and DTI readings, while specificity remained at 95.6%.ConclusionsDTI breast imaging is a noninvasive procedure which demonstrated a high potential utility for cancer detection and serving as a standalone technique or in conjunction with DCE-MRI, the discriminating values of FA, λ1 and λ1–λ3 were high. Their measurements were strongly associated with identification breast malignancy and combined evaluation by DTI parameters and DCE-MRI DTI enhanced the sensitivity, lowered the rate of false-negatives, and completely improved the accuracy of breast lesions differential diagnosis.

Physiological peristaltic flow of Jeffrey fluid inside an elliptic cross section with heat and mass transfer: Exact solutions through Polynomial solution technique

AbstractAn interpretation of heat and mass transfer for the peristaltic flow of a non‐Newtonian Jeffrey fluid inside a duct having an elliptic cross‐section is mathematically investigated. We have considered constant heat absorption for the present study and a descriptive heat as well as mass transfer analysis is carried out. Exact solutions are computed by utilizing a polynomial solution technique to solve the dimensionless partial differential equations appearing in the problem. A purposeful and detailed graphical assessment is provided for the final mathematical results. Velocity as well as temperature profiles attain highest value at the core region of duct while these profiles gradually decline toward duct boundaries. The incrementing value of λ1 is resulting in an increase of flow and since λ1 is the dimensionless ratio of relaxation to retardation time, it means that the increasing value of λ1 results in an increase of relaxation time but it also results in decline of retardation time.

Dependence of Microstructures and Mechanical Properties on the Growth Rate and Composition in Directionally Solidified Mg-Gd Alloys

Microstructures and mechanical properties of directionally solidified Mg-xGd (5.21, 7.96 and 9.58 wt.%) alloys were investigated at a wide range of growth rates (V = 10-200 μm/s) under the constant temperature gradient (G = 30 K/mm). The results showed that when the growth rate was 10 μm/s, different interface morphologies were observed in three tested alloys: cellular morphology for Mg-5.21Gd alloy, a mixed morphology of cellular structure and dendritic structure for Mg-7.96Gd alloy and dendrite morphology for Mg-9.58Gd alloy, respectively. Upon further increasing the growth rate, only dendrite morphology was exhibited in all experimental alloys. The microstructural parameters (λ1, λ2) decreased with increasing the growth rate for all the experimental alloy, and the measured λ1 and λ2 values were in good agreement with Trivedi model and Kattamis-Flemings model, respectively. Vickers hardness and the ultimate tensile strength increased with the increase of the growth rate and Gd content, while the elongation decreased gradually. Furthermore, the relationships between the hardness, ultimate tensile strength, the growth rate and the microstructural parameters were discussed and compared with the previous experimental results.

Properties of hybrid stars with a density-dependent bag model

The phenomena of the deconfinement of hadronic matter into quark matter at high density, relevant to hybrid star (HS) cores, is studied in the present work. The effective chiral model describes the pure hadronic phase while for the quark phase the MIT bag model is chosen with density-dependent bag pressure. Phase transition is achieved using Maxwell construction. The effect of variation of the asymptotic value of the bag pressure (B as) is analyzed w.r.t. the mass and radius of the HSs. The presence of hyperons in the hadronic sector also has a significant effect on the choice of the value of B as. Both the hadronic composition and the choice of B as significantly affect the stability of the star. The gross structural properties of the resultant HS are calculated in a static condition and compared with the various constraints on them from different observational and empirical perspectives. The static properties, like the maximum gravitational mass of the HS obtained with B as = 80 MeV fm−3, is consistent with the limits imposed from the observational analysis of PSR J0348+0432 and PSR J0740+6620. The estimates of R 1.4 and R 1.6 of HSs are found to be within the range prescribed from GW170817 analysis. Also the M–R solutions of the HSs are in excellent agreement with the recently obtained NICER data for PSR J0030+0451. The results of maximum surface redshift, obtained with a hybrid equation of state, satisfy the constraints from 1E 1207.4-5209 and RX J0720.4-3125. The work is also extended to obtain the tidal deformation properties of the HSs. The obtained value of Λ1.4 is consistent with the bound obtained from GW170817 data analysis.

Detecting vortical structures in time-resolved volumetric flow fields

The detection of three-dimensional coherent vortical structures that get advected as well as deformed with time is a challenge. However, it is critical for the statistical analysis of these vortices, for example, the quasi-streamwise vortices (QSVs) in the near field of a turbulent shear layer, where cavitation inception typically occurs. These structures exhibit underlying correlations among different properties that can be derived from the velocity gradients. Exploiting these correlations, a pseudo-Lagrangian vortex detection method is proposed that uses k-means clustering based on vorticity magnitude and direction, values of λ2, strain rate structure, axial stretching, and location. The method facilitates the finding that QSVs have pressure minima that are lower than those in the surrounding flow, including the primary spanwise vortices. These minima typically appear after a period of axial stretching and before contraction events.

Correlation Between Unsteady-State Solidification and Electrochemical Corrosion Parameters of an AlSiMg Alloy

Electrochemical corrosion tests were performed on samples of horizontally solidified Al7Si0.3Mg (wt%) alloy. The investigated solidification and corrosion parameters were growth and cooling rates (VL and TR, respectively), secondary dendritic spacing (λ2), corrosion potential, and corrosion current (ECORR and iCORR, respectively). Optical and scanning electron microscopy analysis were carried out on the samples, and typical solidification microstructure was characterized by primary and eutectic phases (Alα and Alα-eutectic+ Si+ π-Al8Mg3FeSi6+θ-Mg2Si, respectively). The results depicted a higher corrosion resistance in as-cast samples with finer dendritic microstructure, that is, for higher and lower VL/TR and λ2 values, respectively. A mathematical expression characterized the iCORR variation with VL, TR, and λ2. SEM/EDS element maps and point microanalysis showed a strong decreased of Mg and Fe elements within the interdendritic regions due to the corrosion of π and θ intermetallic phases. It was allowed to conclude that Si particles exhibit cathodic behavior in relation to the matrix as well as π and θ intermetallic compounds. A comparative analysis with the literature was also conducted.

Impact of microstructural properties on the crack threshold of aluminium castings

This work focuses on the technological size effect of the cast aluminium alloy EN-AC 46200. Herewith, specimens inheriting specific local cooling rates and therefore varying local dendrite arm spacings are taken from crankcases with hot isostatic pressing (HIP) post-treatment. In order to evaluate the statistically distributed microstructural properties, the dendrite arm spacing λ2 is probabilistically assessed. Thus, the λ2 values follow the lognormal distribution, detached of local solidification times. Crack propagation tests are conducted at varying load ratios, such that the impact of the microstructure by means of λ2 is evaluated. The statistically assessed investigations propose the intrinsic crack threshold to be independent of microstructural properties, in opposite to the long crack threshold which is significantly affected by varying λ2 values due to enhanced crack closure effects. The evaluated cyclic R-curve results can be generalized into a microstructural independent manner. Moreover, the load ratio effect and its convolution with microstructural properties is evaluated based on the Newman approach. The linear extrapolation of the newly raised three-dimensional Newman approach, considering arbitrary λ2 values as technological effect, is validated by literature data and the proposed stress intensity factor threshold course is revealed to be slightly conservative by about twelve percent on average.

The dependency of the microhardnes on microstructure and solidification parameters of directionally solidified Al–4.5wt.%Cu in clay mold

Improvement of material properties is achieved by controlling parameters involved in the solidification process; therefore, understanding them and their implication are essential. This work investigated the dependency of solidification parameters (cooling rate (TR), growth rate (VL), local solidification time (tSL), temperature gradient (G)), microstructure parameters (primary (λ1) and secondary (λ2) dendrite arm spacing), and micro-hardness values (HV) of Al-4.5wt.%Cu in the clay mold. The samples were directionally solidified in Bridgman vertical apparatus and the temperature is recorded during the cooling. The solidification parameters were obtained from the cooling curve. The microstructures and micro-hardness were characterized using an optical microscope and micro-hardness tester. The microstructure parameters were measured and plotted as functions of solidification parameters using linear regression. The relation between HV and microstructure parameters are analyzed. The results show the λ1 and λ2 change inversely with solidification parameters except for tSL. Comparison to other works shows the exponent values of solidification parameters of the clay mold are lower than that of the carbon and stainless-steel mold. The exponent value of λ2 in the clay mold is -0.183, close to the value in the graphite mold. The clay has the potential as mold material since it characteristic close to the graphite.

Investigation of the microstructure and physical properties of directionally solidified ternary Al–8.8La–1.2Ni alloy

This paper systematically studies the microstructure evolution, microhardness and tensile property of Al–8.8La–1.2Ni ternary alloy with directionally solidified under a wide range of solidification rates by Bridgman-type growth apparatus. The directionally solidified microstructure of studied alloy consists aligned dendrites, and eutectics in the region between them. Primary dendrite arm spacing (λ1), secondary dendrite arm spacing (λ2) and microhardness (HV) were measured from both transverse and longitudinal sections of many samples. Also, ultimate tensile strength (σuts), tensile yield strength (σtys), ultimate compressive strength (σucs) and compressive yield strength (σcys) of the solidified many samples at room temperature the dependence of solidification rate (V) were carried out. The present results show that the solidification rate can change both microstructure and mechanical properties effectively. According to these results, it has been found that, for increasing values of V, the values of λ1 and λ2 decrease, the values of HV, σuts, σtys and σcys increase. Relationships between microstructural parameters (λ1, λ2) and mechanical properties (HV, σuts, σtys and σcys) expressed as function of solidification rate using a linear regression analysis method.

Martensitic transformation in stoichiometric NiMn and Ni–Mn-X alloys: A first principles study

The martensitic phase transformation in stoichiometric NiMn alloy and its shape memory effect is investigated using first principles method based on Density Functional Theory (DFT). The elastic properties of the B2 austenite and the L10 martensite phases were compared and the results indicated that the B2 phase has a low elastic shear modulus along the [110] direction giving rise to the formation of L10. Electronic density of states (DOS) calculations showed that the existence of the pseudo-gap appearing at the Fermi level which stabilizes the martensite phase against the austenite depends on both magnetism and the tetragonality ratio. Using geometrically nonlinear theory of martensite it was found that large volume change and twinning shear, and the low value of middle eigenvalue of the transformation stretch tensor (λ2 = 0.8766) are some of the properties of the martensitic transformation in NiMn which inhibit the shape memory effect in this system despite being structurally similar to other shape memory alloys such as NiAl. The effect of the addition of 8 alloying elements on the martensitic transformation and shape memory effect is investigated. The results showed, in agreement with the experimental findings, that addition of Ti and Al can improve the shape memory effect. Also, it was found that among the 8 elements considered here, Al, Ti, and Ge are the most effective alloying elements in enhancing the shape memory properties of NiMn by lowering the transformation temperature, decreasing the volume change, and increasing the value of λ2..

Study of Dry Wear Behavior and Resistance in Samples of a Horizontally Solidified and T6/Heat-Treated Automotive AlSiMg Alloy

To investigate dry wear behavior in an aluminum-based automotive alloy, transient horizontal solidification experiments using a water-cooled directional solidification device have been performed with the Al7Si0.3Mg alloy (wt%). Samples of the as-cast ingot at positions (P) 2, 4, 6, 40, and 80 mm from the cooled interface were subjected to precipitation hardening heat treatment (T6-type). The heat treatment has been applied under the following conditions: solution treatment for 3 h at 520 ± 2 °C, followed by quenching in warm water (70 ± 2 °C), aging for 3 h at 155 ± 2 °C and air-cooling. Dry wear tests were performed on both the as-cast and heat-treated samples. The wear tests were carried out by rotary-fixed ball wear machine means. The analyzed parameters were solidification growth and cooling rates (VL and TR), secondary dendritic spacings (λ2), and wear volume and rate (WV and WR). An interrelation between these parameters has been conducted and experimental mathematical equations have been proposed to characterize the WV and WR dependence on P, VL, TR and λ2. The T6-heat treatment has affected the length of the as-cast dendritic scale, increasing the λ2 values as well as the wear features of the investigated automotive alloy. Finer and coarser dendritic microstructures inherited better wear resistance for the as-cast and heat-treated samples, respectively. An evaluation by occupied area fraction (%IRAF) of interdendritic regions on wear resistance in the as-cast and heat-treated samples has been performed. It has been observed higher and lower IRAF values in the as-cast and heat-treated samples, respectively.

Comparison of the Microstructure of M2 Steel Fabricated by Continuous Casting and with a Sand Mould

AISI M2 steel was smelted in a 150 kg medium-frequency induction furnace and cast to form round billets with a cross-section diameter of 100 mm via a vertical continuous caster and sand mold. The secondary dendrite arm spacing (λ2), cooling rates, permeability and size and distribution of grains and network carbides of the two billets were studied. The results show that the continuous casting process can effectively decrease the λ2 value, permeability and size of the grains and carbides and improve the distribution of the grains and carbides during solidification. The λ2 values of the billets cast with a sand mold and continuous caster are 37.34 μm and 21.14 μm, respectively, and the cooling rate is 3.6 K·s−1 and 12.0 K·s−1, respectively. The area fractions of carbides at the center of the billets cast with the sand mold and continuous caster are 0.24 and 0.16, respectively, and increase by 27.7% and 25.4%, respectively, compared with their average values. The average grain size of billets cast with the sand mold and continuous caster is 69.4 μm and 50.5 μm, respectively. Compared with the sand mold billet, the grain size at the center of the continuous casting billet is reduced by 25.5%. The relationship between the grain size and cooling rate is presented in this paper.

Analytical Solutions in the Framework of Brightness and Color Spectral Pyrometry Methods

The article provides an analytical solution to the problem of pyrometric determination of the actual surface temperature T(K) by calculating its value from a system of three equations, including the results of three measurements of the brightness temperature TS (λі), which were obtained at three wave length sof the spectrum: λ1<λ2<λ3 with unknown emissivity e1, e2 and e3, in the framework of the two main methods of spectral pyrometry according to the patents of Ukraine No.73231 (color) and No.82870 (brightness). It is shown in the article that exact analytical solutions are possible only in cases when the nature of the dispersion of the selective surface e=f(λ) (for example, linear, logarithmic, etc.) is known apriori, which, together with the equation of coupling e2 = F(e1, e3), allows us to determine the exact value of the intermediate (effective) length λ2 waves based on the extreme (or basic) values of λ1 and λ3. The arithmetic mean (for the color method) and the proportional mean (for the brightness method) are use dascoupling equations.

Effect of Squeeze Casting on Microhardness and Microstructure of Al-3Cu-xSi Alloy

Aluminum alloys of the ANSI series 319 present Si and Cu as the main alloying elements and the mechanical strength of these alloys can be improved by the precipitation of the metastable Al2Cu phase. Squeeze Casting is a casting process in which the cast metal is deposited in a metal mold and solidified under certain pressure exerted by a punch. This process provides changes in the microstructure which lead to changes in the mechanical properties of the material such as the increase in the microhardness of the processed alloy. alloys Al-5,5% Si-3% Cu, Al-7,5% Si-3% and Al-9% Si-3% Cu alloys were solidified by the squeeze casting process to analyze the microstructural and microhardness variations. Pressures of 0 MPa, 50 MPa, 100 MPa and 150 Mpa were used. In general, with increasing pressure and composition, the λ2 values decrease from the metal/mold interface, especially at pressures of 150 MPa and Composition of 9%Si, on the other hand the increase of these variables leads to the formation of more phases Al2Cu metastable that have a decrease in the Microhardness of the material, in addition to the formation of other phases due to the proximity to the eutetic.

Novel TiNiCuNb shape memory alloys with excellent thermal cycling stability

The thermal cycling stability of martensitic transformation in (Ti54Ni34Cu12)100-xNbx (x = 0, 6 and 10 at.%) was investigated. The results show that doping Nb into Ti54Ni34Cu12 enhances the thermal cycling stability of the material. After 400 thermal cycles, the shift of martensitic transformation start temperature of Ti54Ni34Cu12 and (Ti54Ni34Cu12)90Nb10 alloys are 1.5 °C and 0.1 °C, respectively. This improvement can be ascribed to the fact that the proper doping of Nb does not significantly reduce the value of λ2, whereas improves the other cofactor conditions (CC2 and CC3) and the yield strength.

The Diffusion Tensor Imaging Properties of the Normal Testicles at 3 Tesla Magnetic Resonance Imaging

The testicles are structured in a well-defined microtubular network formation, which is expected to be reflected in high anisotropic diffusivity. However, preliminary studies reported on low values of fractional-anisotropy (FA) in the normal testicles. Our aim was to design and apply a diffusion-tensor imaging (DTI) protocol in order to elucidate the diffusivity properties of the testicles and their determining factors. 16 healthy volunteers were prospectively scanned at 3T. The protocol included T2-weighted and DTI sequences, the latter using 24 directional diffusion gradients and 3 b-values (0, 100, and 700 s/mm2) that were separated for analysis based on the reference b-value of 0 or 100 s/mm2. Image processing of the two DTI datasets yielded the diffusion vector maps and parametric maps of their corresponding principal diffusion coefficients λ1, λ2, λ3, mean diffusivity and FA. The results demonstrated the feasibility of DTI to provide parametric maps of the testicles. The diffusion tensor parameters obtained using the pair of 0 and 700 s/mm2 b-values, exhibited relatively low diffusivity, with mean λ1 values of 1.36 ± 0.21 × 10-3 mm2/s and low anisotropy, with mean FA values of 0.13 ± 0.05. Analysis of DTI using the 100 and 700 s/mm2 b-values yielded a slight decrease in the diffusivity of 4%-5%, whereas FA remained similar. The diffusivity of the normal testicles is relatively slow, closed-to isotropic and hardly affected by the low b-values regime exclusion. Thus, DTI parameters of the normal testicles are neither dictated by the underlying architectural anisotropy nor microperfusion effects.