Organ preservation after neoadjuvant long-course chemoradiotherapy versus short-course radiotherapy.

BACKGROUND: Potential differences in organ preservation between total neoadjuvant therapy (TNT) regimens integrating long-course chemoradiotherapy (LCCRT) and short-course radiotherapy (SCRT) in rectal cancer remain undefined. PATIENTS AND METHODS: This natural experiment arose from a policy change in response to the COVID-19 pandemic during which our institution switched from uniformly treating patients with LCCRT to mandating that all patients be treated with SCRT. Our study includes 323 locally advanced rectal adenocarcinoma patients treated with LCCRT-based or SCRT-based TNT from January 2018 to January 2021. Patients who achieved clinical complete response were offered organ preservation with watch-and-wait (WW) management. The primary outcome was 2-year organ preservation. Additional outcomes included local regrowth, distant recurrence, disease-free survival (DFS), and overall survival (OS). RESULTS: Patient and tumor characteristics were similar between LCCRT (n = 247) and SCRT (n = 76) cohorts. Median follow-up was 31 months. Similar clinical complete response rates were observed following LCCRT and SCRT (44.5% versus 43.4%). Two-year organ preservation was 40% [95% confidence interval (CI) 34% to 46%] and 31% (95% CI 22% to 44%) among all patients treated with LCCRT and SCRT, respectively. In patients managed with WW, LCCRT resulted in higher 2-year organ preservation (89% LCCRT, 95% CI 83% to 95% versus 70% SCRT, 95% CI 55% to 90%; P = 0.005) and lower 2-year local regrowth (19% LCCRT, 95% CI 11% to 26% versus 36% SCRT, 95% CI 16% to 52%; P = 0.072) compared with SCRT. The 2-year distant recurrence (10% versus 6%), DFS (90% versus 90%), and OS (99% versus 100%) were similar between WW patients treated with LCCRT and SCRT, respectively. CONCLUSIONS: While WW eligibility was similar between cohorts, WW patients treated with LCCRT had higher 2-year organ preservation and lower local regrowth than those treated with SCRT, yet similar DFS and OS. These data support induction LCCRT followed by consolidation chemotherapy as the preferred TNT regimen for patients with locally advanced rectal cancer pursuing organ preservation.

Quantum scaling for the metal-insulator transition in a two-dimensional electron system.

The quantum phase transition observed experimentally in two-dimensional (2D) electron systems has been a subject of theoretical and experimental studies for almost 30 years. We suggest Gaussian approximation to the mean-field theory of the second-order phase transition to explain the experimental data. Our approach explains self-consistently the universal value of the critical exponent 3/2 (found after scaling measured resistivities on both sides of the transition as a function of temperature) as the result of the divergence of the correlation length when the electron density approaches the critical value. We also provide numerical evidence for the stretched exponential temperature dependence of the metallic phase's resistivities in a wide range of temperatures and show that it leads to correct qualitative results. Finally, we interpret the phase diagram on the density-temperature plane exhibiting the quantum critical point, quantum critical trajectory and two crossover lines. Our research presents a theoretical description of the seminal experimental results.

Optimal size threshold for PIRADSv2 category 5 upgrade and its positive predictive value: is it predictive of "very high" likelihood of clinically-significant cancer?

AIM: To identify the optimal size metric and threshold for Prostate Imaging Reporting and Data System (PIRADS) 5 upgrade, calculate its positive predictive value (PPV) for clinically-significant prostate cancer (csPCA), and determine if it is indicative of a "very high" likelihood of csPCA. MATERIALS AND METHODS: One hundred and forty-three PIRADS 4 or 5 lesions were evaluated. Lesion diameters were used to calculate lesion volume (LV). Pearson correlation between maximum lesion diameter (MLD) and LV was calculated. Area under the curve (AUC) for discriminating csPCA (Gleason grade ≥ 3 + 4) was calculated using MLD and LV. Optimal size thresholds (using Youden index) and highly predictive size thresholds were identified for the whole prostate (WP), peripheral zone (PZ), and transitional zone (TZ). RESULTS: There was high correlation between MLD and LV (r=0.77-0.81), with comparable AUCs for MLD and LV in the identification of csPCA in the WP (0.73, 0.72), PZ (0.73, 0.73), and TZ (0.79, 0.75). Optimal MLD thresholds were 1.4, 1.4, and 1.6 cm in the WP, PZ, and TZ respectively, with PPVs of 76%, 81%, and 69%, respectively. An MLD threshold of 2.7 cm would be needed in the WP to achieve a PPV approaching 90%, with sensitivity decreasing to 10%. CONCLUSIONS: There is high correlation between MLD and LV with comparable discrimination of csPCA using each. PIRADSv2's 1.5 cm MLD threshold is near the optimal threshold for PIRADS 5 upgrade but has moderate PPV. A much higher threshold would be needed to increase its PPV, with significant sacrifice in sensitivity.

RECENT DEVELOPMENTS IN COMPUTERISED ANALYSIS OF THERMOLUMINESCENCE GLOW CURVES: SOFTWARE CODES, MECHANISMS AND DOSIMETRIC APPLICATIONS.

The computerised deconvolution of thermoluminescence glow curves into component glow peaks is discussed in detail with special emphasis on advances of the subject post 2013. A plethora of computer codes have been developed using models based on first-order kinetics, second-orders kinetics, interactive traps and continuous distributions of activation energies. The glow curves of several materials are displayed and discussed along with new and improved dosimetric applications:precision effects of heating rate, heavy charged particles, mixed field α/ϒ dosimetry, fading and dose-response linearity. Finally recommendations are made for future efforts.

Giant fluctuations of local magnetoresistance of organic spin valves and the non-Hermitian 1D Anderson model.

Motivated by recent experiments, where the tunnel magnetoresitance (TMR) of a spin valve was measured locally, we theoretically study the distribution of TMR along the surface of magnetized electrodes. We show that, even in the absence of interfacial effects (like hybridization due to donor and acceptor molecules), this distribution is very broad, and the portion of area with negative TMR is appreciable even if on average the TMR is positive. The origin of the local sign reversal is quantum interference of subsequent spin-rotation amplitudes in the course of incoherent transport of carriers between the source and the drain. We find the distribution of local TMR exactly by drawing upon formal similarity between evolution of spinors in time and of the reflection coefficient along a 1D chain in the Anderson model. The results obtained are confirmed by the numerical simulations.

On the proton kinetic energy in H2O and in nanotube water.

We calculated the kinetic energies of the H-atom in ice Ih between 5 and 269 K and in water in the range 293-673 K. To do so we used the literature optical vibration frequencies of ice and water of the different phases assuming the harmonic approximation and decoupling between the degrees of freedom of translation, rotation (libration), and internal vibrations. Apart for ice at 269 K, good agreement was obtained with published experimental values for both cases. Similar agreement with experiment was found for the case of water confined in 14 A diameter carbon nanotubes at 268 K. However, serious deviations from measured values were found in nanotube water in the range 5-230 K. Possible reasons for those deviations are discussed.

On anomalies in elastic electron scattering cross sections from protons.

A critical examination of recent elastic electron scattering reports on H-containing samples is carried out. We show that all results are consistent with the conclusion that no anomaly exists in the measured e-H scattering intensities as compared to e-scattering from other light atoms such as D or C. The scattering results are, in fact, in agreement with the classical Rutherford formula and there is no need to invoke short-lived quantum entanglement of the protons to explain the existing data. The neutron-proton scattering intensities on H-containing samples were also examined and found to agree with standard cross sections. Also no theoretical evidence was found supporting the existence of the reported anomalies.

Doppler widths in electron quasielastic scattering from molecular gases.

Recent quasielastic electron scattering experiments on some molecular gases at E(e) > or = 1.8 keV have shown that the scattering is from single isotopes of the atomic components of the gas. The scattered electron lines at definite angles are Doppler broadened by the instantaneous kinetic energy (KE) of the scattering atoms. We calculated the KE of the scattering atoms by accounting for translation, rotation, and all normal modes of vibrations of the molecule. The results reveal some large and fundamental differences from literature estimates.

Nuclear Resonance Photon Scattering Studies of N 2 Adsorbed on Grafoil and of NaNO 2 Single Crystal.

The nuclear resonance photon scattering (NRPS) from (15)N2 adsorbed on graphite was investigated. The resonantly scattered intensities from the 6324 keV level of (15)N with the photon beam parallel and perpendicular to the adsorbing grafoil planes was measured at 140 K and coverages below 0.7 monolayers (ML), where the (15)N2 occur in the vapor phase. The data were used for deducing the out-of-plane tilt angle of adsorbed N2 relative to the graphite surface and the results were compared with grand canonical Monte Carlo (GCMC) calculations. Using the same method, a single crystal of NaNO2 was studied by measuring the scattering intensities with the nitrite planes aligned parallel and perpendicular to the photon beam. At 80 K, a huge anisotropy (R≈3.6) was observed, caused by the anisotropy in the zero-point motion of the internal modes of vibration of the NO2 ion. The variation of the scattering intensity from a powdered isotopic (15)NaNO2 sample versus T in the range 12 K to 297 K was also measured and explained by accounting for the internal and external vibrational modes in NaNO2.

Prodromal urticaria with seronegative rheumatoid arthritis.

This case report describes an association of chronic diurnal urticaria with the onset of seronegative arthritis in a 38-year-old woman after her first pregnancy. Remission of the urticaria and rheumatoid arthritis occurred with methotrexate therapy. The variety of urticarial lesions that can be seen with arthritis are noted.