Comparison of tumor histology to dynamic contrast enhanced magnetic resonance imaging-based physiological estimates

Purpose

The purpose of this study was to compare histologically determined cellularity and extracellular space to dynamic contrast-enhanced magnetic resonance imaging (DCE MRI)-based maps of a two-compartment model's parameters describing tumor contrast agent extravasation, specifically tumor extravascular extracellular space (EES) volume fraction (v_e), tumor plasma volume fraction (v_p) and volume-normalized contrast agent transfer rate between tumor plasma and interstitium (K_TRANS/V_T).

Materials and Methods

Obtained v_e, v_p and K_TRANS/V_T maps were estimated from gadolinium diethylenetriamine penta-acetic acid DCE T₁-weighted gradient-echo images at resolutions of 469, 938 and 2500 μm. These parameter maps were compared at each resolution to histologically determined tumor type, and the high-resolution 469-μm maps were compared with automated cell counting using Otsu's method and a color-thresholding method for estimated intracellular (V_{intracellular}) and extracellular (V_{extracellular}) space fractions.

Results

The top five K_TRANS/V_T values obtained from each tumor at 469 and 938 μm resolutions are significantly different from those obtained at 2500 μm (P<.0001) and from one another (P=.0014). Using these top five K_TRANS/V_T values and the corresponding tumor EES volume fractions v_e, we can statistically differentiate invasive ductal carcinomas from noninvasive papillary carcinomas for the 469- and 938-μm resolutions (P=.0017 and P=.0047, respectively), but not for the 2500-μm resolution (P=.9008). The color-thresholding method demonstrated that v_e measured by DCE MRI is statistically similar to histologically determined EES. The V_{extracellular} obtained from the color-thresholding method was statistically similar to the v_e measured with DCE MRI for the top 10 K_TRANS/V_T values (P>.05). DCE MRI-based K_TRANS/V_T estimates are not statistically correlated with histologically determined cellularity.

Conclusion

DCE MRI estimates of tumor physiology are a limited representation of tumor histological features. Extracellular spaces measured by both DCE MRI and microscopic analysis are statistically similar. Tumor typing by DCE MRI is spatial resolution dependent, as lower resolutions average out contributions to voxel-based estimates of K_TRANS/V_T. Thus, an appropriate resolution window is essential for DCE MRI tumor diagnosis. Within this resolution window, the top K_TRANS/V_T values with corresponding v_e are diagnostic for the tumor types analyzed in this study.     

Investigations on the spin Hamiltonian parameters and defect structure for the interstitial Mo centre in TiO2

The spin Hamiltonian parameters, g factors g_i (i = x, y, z) and the hyperfine structure constants A_i for the interstitial Mo⁵⁺ centre in rutile TiO₂ are quantitatively investigated from the perturbation formulas of these parameters for a 4d¹ ion in rhombically compressed octahedra. From the studies, the local compression parameter τ′ (≈0.024) and the rhombic distortion angle δ?′ (≈1.74°) around the impurity Mo⁵⁺ are smaller than the host values (≈0.091 and 3.5°). This means that the oxygen octahedron in the impurity centre has less rhombic distortion than that on the host interstitial site due to the Jahn–Teller effect and occupation of the impurity. The above local lattice distortion of the studied impurity centre is also discussed.     

Dispersion characteristics for low-frequency magnetoelectric coefficients in bulk ferrite-piezoelectric composites

Ferrite-piezoelectric composites are magnetoelectric (ME) due to the interaction between magnetic and electrical subsystems through mechanical forces. A theory for the low-frequency Maxwell-Wagner relaxation in ME coefficients is discussed for bulk composites of nickel or cobalt ferrite and lead zirconate titanate (PZT). ME coefficients versus frequency spectra show two types of relaxation, over 0.1-100 μHz and 1-1000 Hz. The relaxation frequencies and the magnitude of the ME coefficients are dependent on the electrical and composite parameters and volume fraction for the two phases. The ME coefficient α_E is in the range 10⁻¹-10⁴ mV/cm Oe, higher in cobalt ferrite-PZT than for nickel ferrite-PZT, and is strongly dependent on PZT volume fraction v. Estimates of α_E and relaxation frequencies versus v provided here are useful for engineering composites with maximum ME effects for specific frequency bands.     

The far-infrared and microwave spectra of the CH radical in the v = 1 level of the XΠ state

Transitions between the spin-rotational levels of the ¹²CH radical in the v = 1 level of the X²Π state have been studied by the technique of laser magnetic resonance at far-infrared wavelengths. The data have been combined with a measurement of lambda-doubling transition frequencies at 7 GHz to determine an improved set of molecular parameters for CH in the v = 1 level. The parameters provide information on the effects of vibrational excitation on the structural properties of CH. Accurate predictions of the transition frequencies between the low-lying levels of the radical in the absence of a magnetic field have also been made.Small inconsistencies in the least-squares fit of the laser magnetic resonance data prompted re-measurement of three far-infrared laser frequencies, the 122.5 μm line of CH₂F₂ pumped by 9R(22), the 122.5 μm line of CH₂F₂ pumped by 9P(8) and the 554.4 μm line of CH₂CF₂ pumped by 10P(14). The new measurements differ by as much as 3.8 MHz from those made previously and are more accurate; they also remove the inconsistencies in the fit. The re-measured frequencies of the two 122.5 μm lines are identical within experimental error which suggests that the far-infrared lasing transition is the same, namely the ^rR₂₃(32) transition in the v₉=1 level of CH₂F₂.     

Permeability and electric resistivity of spin-sprayed Zn ferrite films for high-frequency device applications

By spin-spray ferrite plating, an aqueous process, we prepared Zn_xFe_3−xO₄ (0?x?0.97) films at 90 °C on polyimide and glass substrates, on which complex permeability (μ=μ′–jμ″) was measured. As Zn content x increases from 0 to 0.70 static permeability, μ_s, increases from 14 to 119, but natural resonance frequency, f_r, reduces from 1 GHz to 200 MHz. This is because magnetic anisotropy field decreases more rapidly than saturation magnetization. With increasing x DC electric resistivity, ρ, increases, exceeding 50 Ω cm (a measure of the lower limit for the high-frequency application) when x>0.15. Film with x=0.70 has relatively high μ′≈119 and μ″=0 up to 20 MHz, and is promising to be used as MHz core inductors. Film with x=0.36 has relatively high μ′=80 and μ″=0 up to 100 MHz, and it may be used as inductors at the ten MHz range and noise suppression sheets at the hundred MHz range.     

Multi-isotopologue analyses of new vibration-rotation and pure rotation spectra of ZnH and CdH

High resolution infrared emission spectra of ZnH, ZnD, CdH, and CdD have been recorded with a Fourier transform spectrometer. The v = 1 → 0 and v = 2 → 1 bands of ZnH, ZnD, CdH, and CdD, as well as the v = 3 → 2 band of ZnD were observed for the X²Σ⁺ ground electronic state. In addition, new rotational spectra have been recorded for CdH and CdD using a tunable far-infrared spectrometer, and pure rotational transitions in the v = 1 level of the ground state were measured. The new data were combined with the previous data from diode laser infrared spectra and pure rotation spectra of ZnH/ZnD and CdH/CdD available in the literature. The data from all isotopologues were fitted together using a Dunham-type energy level expression for ²Σ⁺ states, and Born-Oppenheimer breakdown correction parameters were obtained. The equilibrium rotational constants (B_e) of ⁶⁴ZnH, ⁶⁴ZnD, ¹¹⁴CdH, and ¹¹⁴CdD were determined to be 6.691332(17), 3.402156(7), 5.447074(18), and 2.750761(6) cm⁻¹, respectively, and the associated equilibrium internuclear distances (r_e) are 1.593478(2), 1.593001(2), 1.760098(3), and 1.759695(2) Å, respectively. Simple reduced mass scaling for the spin-rotation interaction constants of ZnH and CdH fully accounted for their isotopologue dependence, and no Born-Oppenheimer breakdown correction was required for these parameters.     

Monte Carlo study of the critical behavior and magnetic properties of La2/3Ca1/3MnO3 thin films

Critical exponents offer important information concerning the interaction mechanisms near the paramagnetic to ferromagnetic transition. In this work a Monte Carlo-Metropolis simulation of the critical behavior in La_2/3Ca_1/3MnO₃ thin films is addressed. Canonical ensemble averages for magnetization per site, magnetic susceptibility and specific heat of stoichiometric manganite within a three-dimensional classical Heisenberg model with nearest magnetic neighbor interactions are computed. The La_2/3Ca_1/3MnO₃ thin films were simulated addressing the thickness influence and thermal dependence. In the model, Mn magnetic ions are distributed on a simple cubic lattice according to the perovskite structure of this manganite. Ferromagnetic coupling for the bonds Mn³⁺-Mn³⁺(e_g-e_g′), Mn³⁺-Mn⁴⁺(e_g-d³) and Mn³⁺-Mn⁴⁺(e_g′-d³) were taken into account. On the basis of finite-size scaling theory, our best estimates of critical exponents, linked to the ferromagnetic to paramagnetic transition, for the correlation length, specific heat, magnetization and susceptibility are, respectively: v=0.56±0.01, α=0.16±0.03, β=0.34±0.04γ and γ=1.17±0.05. These theoretical results are consistent with the Rushbrooke equalitiy α+2β+γ=2.     

Porous microstructures induced by picosecond laser scanning irradiation on stainless steel surface

A study of porous surfaces having micropores significantly smaller than laser spot on the stainless steel 304L sample surface induced by a picosecond regenerative amplified laser, operating at 1064 nm, is presented. Variations in the interaction regime of picosecond laser pulses with stainless steel surfaces at peak irradiation fluences(F_pk=0.378–4.496 J/cm²) with scanning speeds(v=125–1000 μm/s) and scan line spacings(s=0–50 μm) have been observed and thoroughly investigated. It is observed that interactions within these parameters allows for the generation of well-defined structured surfaces. To investigate the formation mechanism of sub-focus micropores, the influence of key processing parameters has been analyzed using a pre-designed laser pulse scanning layout. Appearances of sub-focus ripples and micropores with the variation of laser peak fluence, scanning speed and scan line spacing have been observed. The dependencies of surface structures on these interaction parameters have been preliminarily verified. With the help of the experimental results obtained, interaction parameters for fabrication of large area homogeneous porous structures with the feature sizes in the range of 3–15 μm are determined.     

A comprehensive evaluation and impact of normalization of generalized tracer kinetic model parameters to characterize blood-brain-barrier permeability in normal-appearing and tumor tissue regions of patients with glioma

Rationale and objectivesTo comprehensively evaluate robustness and variations of DCE-MRI derived generalized-tracer-kinetic-model (GTKM) parameters in healthy and tumor tissues and impact of normalization in mitigating these variations on application to glioma.Materials (patients) and methodsA retrospective study included pre-operative 31 high-grade-glioma(HGG), 22 low-grade-glioma(LGG) and 33 follow-up data from 10 patients a prospective study with 4 HGG subjects. Voxel-wise GTKM was fitted to DCE-MRI data to estimate K^trans, v_e, v_b. Simulations were used to evaluate noise sensitivity. Variation of parameters with-respect-to arterial-input-function (AIF) variation and data length were studied. Normalization of parameters with-respect-to mean values in gray-matter (GM) and white-matter (WM) regions (GM-Type-2, WM-Type-2) and mean curves (GM-Type-1, WM-Type-1) were also evaluated. Co-efficient-of-variation(CoV), relative-percentage-error (RPE), Box-Whisker plots, bar graphs and t-test were used for comparison.ResultsGTKM was fitted well in all tissue regions. K^trans and v_e in contrast-enhancing (CE) has shown improved noise sensitivity in longer data. v_b was reliable in all tissues. Mean AIF and C(t) peaks showed ~38% and ~35% variations. During simulation, normalizations have mitigated variations due to changes in AIF amplitude in K^trans and v_b.. v_e was less sensitive to normalizations. CoV of K^trans and v_b has reduced ~70% after GM-Type-1 normalization and ~80% after GM-Type-2 normalization, respectively. GM-Type-1 (p = 0.003) and GM-Type-2 (p = 0.006) normalizations have significantly improved differentiation of HGG and LGG using K^trans.ConclusionK^trans and v_b can be reliably estimated in normal-appearing brain tissues and can be used for normalization of corresponding parameters in tumor tissues for mitigating inter-subject variability due to errors in AIF. Normalized K^trans and v_b provided improved differentiation of HGG and LGG.     

Fourier transform infrared emission spectra of MnH and MnD

Fourier transform infrared emission spectra of MnH and MnD were observed in the ground X⁷Σ⁺ electronic state. The vibration-rotation bands from v = 1 → 0 to v = 3 → 2 for MnH and from v = 1 → 0 to v = 4 → 3 for MnD were recorded at an instrumental resolution of 0.0085 cm⁻¹. Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant (ω_e) for MnH was found to be 1546.84518(65) cm⁻¹, the equilibrium rotational constant (B_e) is 5.6856789(103) cm⁻¹ and the eqilibrium bond distance (r_e) was determined to be 1.7308601(47) Å.     

The electron neutrino oscillation problem

If we accept the Moscow tritium decay results, indicating that v_e is mostly made of mass 14–44 eV components, and if we exclude near degeneracies between these heavier components, we find rather tight correlations betweenv_e → v_e oscillations in different ranges of distance/energy. This argument allows a closer comparison between experiments in different ranges, and suggests that some results (or interpretations) are in conflict. For example, the absence of oscillations in accelerator experiments puts a stringent bound on reactor and solar effects, contrary to some reactor results and to the popular interpretation of the solar neutrino puzzle. Non-diagonal v_e → v_α(α ≠ e) effects are also bounded. This adds further interest to checking the tritium decay result and to examining possible theoretical reasons for mass degeneracy.     

An experimental limit on the decayK +→μ+ v e

We have searched for the decay modeK ⁺→μ⁺ v _e by looking for thev _e interactions in a neon/hydrogen bubble chamber. The observed events with electrons are consistent with being produced byv _e from the decaysK ⁺→π⁰ e ⁺ v _e . We set a 90% confidence level upper limit of 0.4% for the μ⁺ v _e decay mode of positive kaons.     

Effects of high power ultrasonic vibration on temperature distribution of workpiece in dry creep feed up grinding

Temperature history and distribution of steel workpiece (X20Cr13) was measured by a high tech infrared camera under ultrasonic assisted dry creep feed up grinding. For this purpose, a special experimental setup was designed and fabricated to vibrate only workpiece along two directions by a high power ultrasonic transducer. In this study, ultrasonic effects with respect to grinding parameters including depth of cut (a_e), feed speed (v_w), and cutting speed (v_s) has been investigated. The results indicate that the ultrasonic vibration has considerable effect on reduction of temperature, depth of thermal damage of workpiece and width of temperature contours. Maximum temperature reduction of 25.91% was reported at condition of v_s = 15 m/s, v_w = 500 mm/min, a_e = 0.4 mm in the presence of ultrasonic vibration.     

A search for decays of heavy neutrinos in the mass range 0.5–2.8 GeV

A search for decays of heavy neutrinos was conducted by the CHARM Collaboration in a prompt neutrino beam produced by dumping 400 GeV protons in a Cu target, and in the CERN wide-band neutrino beam produced by 400 GeV primary protons. No candidate event was found. In the beam-dump experiment heavy neutrinos have been assumed to be produced by mixing in charmed D meson decays. Neutrinos decaying into e⁺e⁻v_e, μ⁺e⁻v_μ, and μ⁺μ⁻v_μ were searched for. Limits of |U_ei|², |U_μi|² < 10⁻⁷ were obtained for neutrino masses around 1.5 GeV. In the wide-band experiment heavy neutrinos were assumed to be produced by neutral-current neutrino interactions in the CHARM calorimeter. Here a search was made for neutrinos decaying into a μ and hadrons. This experiment is sensitive to decays of neutrinos with mass in the range 0.5–2.8 GeV with limits of |U_μi|² < 3 × 10⁻⁴ for masses around 2.5 GeV. These measurements extend our previous results in the mass range 10–400 MeV.     

Limits on the τ neutrino electromagnetic properties from single photon searches ate + e − colliders

We set limits on the magnetic moment and charge radius of the τ neutrino by examining the contributions to the processe ⁺ e ^?→v \(\bar \nu \) γ due to such interactions. We find thatK(ν_τ)<4×10^?6 (i.e.μ(ν_τ)<4×10^?6μ _B , μ _B =e/2m _e ) and 〈r ²〉<2×10^?31 cm² using the combined data of the MAC, ASP, CELLO, and Mark J collaborations for this process. We briefly discuss whether these bounds can be improved in any futuree ⁺ e ^? experiments.     

Compact WDM demultiplexer for seven channels in photonic crystal

We demonstrate a new device concept for wavelength division demultiplexing based on planar photonic crystal waveguides. The filtering of wavelength channels is realized by shifting the cutoff frequency of the fundamental photonic bandgap mode in consecutive sections of the waveguide. The shift is realized by modifying the size of the border holes.The proposed demultiplexer has an area equal to (16.5 μm × 6.5 μm) and thus it is verified that this structure is very small and can be integrated easily into optical integrated circuits with nanophotonic technologies. The output wavelengths of designed structure can be tuned for communication applications, around 1550 nm. The wavelengths of demultiplexer channels are λ₁ = 1.590 μm, λ₂ = 1.566 μm, λ₃ = 1.525 μm, λ₄ = 1.510 μm, λ₅ = 1.484 μm, λ₆ = 1.450 μm, λ₇ = 1.400 μm respectively. Designs offering improvement of number of the separate wavelengths (seven), miniaturization of the structure (107.25 μm²) is our aim in this work.In our structure, we consider that the 2D triangular lattice photonic crystal is composed of air holes surrounded by dielectric. Its parameters are: radius of holes (r = 0.130 μm), lattice constant (a = 0.380 μm), and index of membrane (n = 3.181:InP). The numerical model used to simulate the structure of the demultiplexer is based on the finite difference time domain (FDTD).     

Photoinduced effect in Ga-Ge-S based thin films

Glassy films of Ga₁₀Ge₂₅S₆₅ with 4 μm thickness were deposited on quartz substrates by electron beam evaporation. Photoexpansion (PE) (photoinduced increase in volume) and photobleaching (PB) (blue shift of the bandgap) effects have been examined. The exposed areas have been analyzed using perfilometer and an expansion of 1.7 μm (ΔV/V ≈ 30%) is observed for composition Ga₁₀Ge₂₅S₆₅ exposed during 180 min and 3 mW/cm² power density. The optical absorption edge measured for the film Ge₂₅Ga₁₀S₆₅ above and below the bandgap show that the blue shift of the gap by below bandgap photon illumination is considerable higher (ΔE_g = 440 meV) than ΔE_g induced by above bandgap illumination (ΔE_g = 190 meV). The distribution of the refraction index profile showed a negative change of the refraction index in the irradiated samples (Δn = −0.6). The morphology was examined using a scanning electron microscopy (SEM). The chemical compositions measured using an energy dispersive analyzer (EDX) indicate an increase of the oxygen atoms into the irradiated area. Using a Lloyd's mirror setup for continuous wave holography it was possible to record holographic gratings using the photoinduced effects that occur in them. Diffraction efficiency up to 25% was achieved for the recorded gratings and atomic force microscopy images are presented.     

Weinberg angle in the neutrino-electron scattering

According to my recent analysis, in which the use ofM _z has been found to give a more precise sin² θ _w than the use ofG _F inv _μ e→v _μ e scattering, I make calculations of sin² θ w in this process withM _z input including the full one-loop and all the leading log corrections. The result from the present data of cross-section σ(v _μ e) = (1.55±0.20)x10^?42 E _v andZ boson massM _z =92.6±1.7 GeV is sin² θ _w =0.228±0.016, which is in good agreement with the value 0.227±0.014 derived through the usual method from the data of \(v_\mu ,\bar v_\mu e\) and \(v_e ,\bar v_e e\) scatterings, and quite consistent with the world-average sin² θ w=0.228±0.004.