First Measurement of Hard Exclusive π^{-}Δ^{++} Electroproduction Beam-Spin Asymmetries off the Proton

The polarized cross-section ratio σ_{LT^{'}}/σ_{0} from hard exclusive π^{-}Δ^{++} electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2  GeV/10.6  GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5  GeV^{2} up to 7  GeV^{2}. The reaction provides a novel access to the d-quark content of the nucleon and to p→Δ^{++} transition generalized parton distributions. A comparison to existing results for hard exclusive π^{+}n and π^{0}p electroproduction is provided, which shows a clear impact of the excitation mechanism, encoded in transition generalized parton distributions, on the asymmetry.

First CLAS12 Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries in the Extended Valence Region

Deeply virtual Compton scattering (DVCS) allows one to probe generalized parton distributions describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.6 GeV electron beam scattering from unpolarized protons. The results greatly extend the Q^{2} and Bjorken-x phase space beyond the existing data in the valence region and provide 1600 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies.

First Measurement of Λ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

We report results of Λ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014 GeV electron beam. These results represent the first measurements of the Λ multiplicity ratio and transverse momentum broadening as a function of the energy fraction (z) in the current and target fragmentation regions. The multiplicity ratio exhibits a strong suppression at high z and an enhancement at low z. The measured transverse momentum broadening is an order of magnitude greater than that seen for light mesons. This indicates that the propagating entity interacts very strongly with the nuclear medium, which suggests that propagation of diquark configurations in the nuclear medium takes place at least part of the time, even at high z. The trends of these results are qualitatively described by the Giessen Boltzmann-Uehling-Uhlenbeck transport model, particularly for the multiplicity ratios. These observations will potentially open a new era of studies of the structure of the nucleon as well as of strange baryons.

Learning Needle Placement in Soft Tissue With Robot-assisted Navigation

BACKGROUND/AIM

The aim of this phantom study was to evaluate the learning curves of novices practicing how to place a cone-beam computed tomography (CBCT)-guided needle using a novel robotic assistance system (RAS).

MATERIALS AND METHODS

Ten participants performed 18 punctures each with random trajectories in a phantom setting, supported by a RAS over 3 days. Precision, duration of the total intervention, duration of the needle placement, autonomy, and confidence of the participants were measured, displaying possible learning curves.

RESULTS

No statistically significant differences were observed in terms of needle tip deviation during the trial days (mean deviation day 1: 2.82 mm; day 3: 3.07 mm; p=0.7056). During the trial days, the duration of the total intervention (mean duration: day 1: 11:22 min; day 3: 07:39 min; p<0.0001) and the duration of the needle placement decreased (mean duration: day 1: 03:17 min; day 3: 02:11 min; p<0.0001). In addition, autonomy (mean percentage of achievable points: day 1: 94%; day 3: 99%; p<0.0001) and confidence of the participants (mean percentage of achievable points: day 1: 78%; day 3: 91%; p<0.0001) increased significantly during the trial days.

CONCLUSION

The participants were already able to carry out the intervention precisely using the RAS on the first day of the trial. Throughout the trial, the participants' performance improved in terms of duration and confidence.

Observation of Correlations between Spin and Transverse Momenta in Back-to-Back Dihadron Production at CLAS12

We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e^{'}pπ^{+}X events, where Δϕ is the difference of the azimuthal angles of the proton and pion in the virtual photon and target nucleon center-of-mass frame, indicate that correlations between the spin and transverse momenta of hadrons produced in the target- and current-fragmentation regions may be significant. The measured beam-spin asymmetries provide a first access in dihadron production to a previously unexplored leading-twist spin- and transverse-momentum-dependent fracture function. The fracture functions describe the hadronization of the target remnant after the hard scattering of a virtual photon off a quark in the target particle and provide a new avenue for studying nucleonic structure and hadronization.

Observation of Azimuth-Dependent Suppression of Hadron Pairs in Electron Scattering off Nuclei

We present the first measurement of dihadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the gibuu model, which suggests that hadrons form near the nuclear surface and undergo multiple scattering in nuclei.These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei.

Selective internal radioembolization (SIRT) allows to control liver metastases of gastrointestinal stromal tumors (GIST) failing treatment with tyrosine kinase inhibitors (TKI)

11540

Background: The liver and the peritoneum are the main area of metastatic spread in GIST. Liver resection does not play a role for hepatic metastases in comparison to f.e. colorectal cancer. If hepatic metastases are the only or major area of tumor progression and are resistant to available TKIs due to a missing mutation in KIT/PDGFRA/SDH (‘wildtype’) or after treatment with 1st/2nd/3rd/4th line therapy, interventional radioembolization with yttrium-90 (90Y) microspheres are promising treatment options, as radiation doses as high as 200Gy can be applied locally. We analyzed the long-term results of SIRT with respect to hepatic-progression-free survival (HEP-PFS) in a consecutive cohort of patients Methods: From 1/2008 to 1/2018, 2^6 pts (12f, 14m) with biopsy proven liver metastases of GIST which were the only (n = 13) or the dominant site of progression (n = 12) were treated by SIRT. Median age at GIST diagnosis had been 51.8 yrs and when receiving SIRT was 57.6yrs (range, 18–75yrs). The mutational status was ‘wildtype’ (n = 7, 2 NF-1), exon 11 (n = 7), exon 11+2nd mutation (n = 7), exon 9 (n = 3), exon 9+2ndmut (n = 1), and, exon 13 (n = 1). All patients except of two had prior TKI therapy: 1 line n = 3, 2 lines n = 11, 3-4 lines n = 9. Follow-up after SIRT was done via dynamic MRI and contrast-enhanced (CE)-CT, the median follow-up is 33.6 mos (range, 12-108mos) and all patients were followed until death Results:.The median hepatic-progression free survival (HEP-PFS) after SIRT was 17 months (range, 5-53+, 95%CI 10.7-23.8 mos). Of the patients with concomitant extrahepatic disease, the extraHEP-PFS was median 10 months. Twelve patients received next-line TKI therapy for progressive extrahepatic disease, whereas six patients required this for progressive liver metastases. When comparing the results according to the mutational status, patients with a ‘wildtype’ tumor showed a better median HEP-PFS of 19 mos (range, 12-53+, 95%CI 16.7-21.2 mos.) in comparison to KIT exon 9/11/13 mutated patients with only 14 months (range, 4-34 mos., 95%CI 6.5-21.4 mos), p < 0.11 (Wilcoxon). Conclusions: 90Y radioembolization (SIRT) offers a safe and effective treatment for patients with liver metastases of GISTs being the dominant site of tumor progression and with no drug treatment options available. In patients known to have no mutation in KIT/PDGFRA (wt, also NF-1 associated) it looks whether the results might be even more promising and SIRT could be used in earlier treatment lines.

Multidimensional, High Precision Measurements of Beam Single Spin Asymmetries in Semi-inclusive π^{+} Electroproduction off Protons in the Valence Region

High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here a high precision multidimensional study of single π^{+} SIDIS data over a large kinematic range in Bjorken x, fractional energy, and transverse momentum of the hadron as well as photon virtualities Q^{2} ranging from 1-7  GeV^{2}. In particular, the structure function ratio F_{LU}^{sinϕ}/F_{UU} has been determined, where F_{LU}^{sinϕ} is a twist-3 quantity that can reveal novel aspects of emergent hadron mass and quark-gluon correlations within the nucleon. The data's impact on the evolving understanding of the underlying reaction mechanisms and their kinematic variation is explored using theoretical models for the different contributing transverse momentum dependent parton distribution functions.

Measurement-Induced Dark State Phase Transitions in Long-Ranged Fermion Systems

We identify an unconventional algebraic scaling phase in the quantum dynamics of long-range hopping, free fermions, which are exposed to continuous local measurements. The algebraic phase occurs for hopping decay exponents 1<p≲3/2, and features an algebraic entanglement entropy growth, and a slow algebraic decay of the density-density correlation function, both with a fractional exponent. It is separated from a critical phase with logarithmic entanglement growth at small, and an area law phase with constant entanglement entropy at large monitoring rates. A perturbative renormalization group analysis predicts that the transitions to the long-range phase correspond to an unconventional, modified sine-Gordon theory. Exact numerical simulations of the monitored wave functions are in excellent agreement with an analytical replica field theory approach, which confirms the view of the measurement-induced phase transition as a quantum phase transition in the dark state of an effective, non-Hermitian Hamiltonian.

Improved Λp Elastic Scattering Cross Sections between 0.9 and 2.0 GeV/c as a Main Ingredient of the Neutron Star Equation of State

Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state. Yet, compared to other elastic scattering processes, there is very little data on Λ-N scattering. This experiment utilized the CEBAF Large Acceptance Spectrometer (CLAS) detector to study the Λp→Λp elastic scattering cross section in the incident Λ momentum range 0.9-2.0  GeV/c. These are the first data on this reaction since the 1970s. The new cross sections have significantly better accuracy and precision than the existing world data, and the techniques developed here can also be used in future experiments.

First Measurement of Timelike Compton Scattering

We present the first measurement of the timelike Compton scattering process, γp→p^{'}γ^{*}(γ^{*}→e^{+}e^{-}), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25<Q^{'2}<9  GeV^{2}, squared momentum transferred 0.1<-t<0.8  GeV^{2}, and average total center-of-mass energy squared s=14.5  GeV^{2}. The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a way to test the universality of the generalized parton distributions. The angular asymmetry of the decay leptons accesses the real part of the Compton form factors and thus the D-term in the parametrization of the generalized parton distributions.

GMP-compliant production of [68Ga]Ga-NeoB for positron emission tomography imaging of patients with gastrointestinal stromal tumor

Background

[⁶⁸Ga]Ga-NeoB is a novel DOTA-coupled Gastrin Releasing Peptide Receptor (GRPR) antagonist with high affinity for GRPR and good in vivo stability. This study aimed at (1) the translation of preclinical results to the clinics and establish the preparation of [⁶⁸Ga]Ga-NeoB using a GMP conform kit approach and a licensed ⁶⁸Ge/⁶⁸Ga generator and (2) to explore the application of [⁶⁸Ga]Ga-NeoB in patients with gastrointestinal stromal tumors (GIST) before and/or after interventional treatment (selective internal radiotherapy, irreversible electroporation, microwave ablation).

Results

Validation of the production and quality control of [⁶⁸Ga]Ga-NeoB for patient use had to be performed before starting the GMP production. Six independent batches of [⁶⁸Ga]Ga-NeoB were produced, all met the quality and sterility criteria and yielded 712 ± 73 MBq of the radiotracer in a radiochemical purity of > 95% and a molar activity of 14.2 ± 1.5 GBq/μmol within 20 min synthesis time and additional 20 min quality control. Three patients (2 females, 1 male, 51–77 yrs. of age) with progressive gastrointestinal stromal tumor metastases in the liver or peritoneum not responsive to standard tyrosine kinase inhibitor therapy underwent both [⁶⁸Ga]Ga-NeoB scans prior and after interventional therapy. Radiosynthesis of ⁶⁸Ga-NeoB was performed using a kit approach under GMP conditions. No specific patient preparation such as fasting or hydration was required for [⁶⁸Ga]Ga-NeoB PET/CT imaging. Contrast-enhanced PET/CT studies were performed. A delayed, second abdominal image after the administration of the of [⁶⁸Ga]Ga-NeoB was acquired at 120 min post injection.

Conclusions

A fully GMP compliant kit preparation of [⁶⁸Ga]Ga-NeoB enabling the routine production of the tracer under GMP conditions was established for clinical routine PET/CT imaging of patients with metastatic GIST and proved to adequately visualize tumor deposits in the abdomen expressing GRPR. Patients could benefit from additional information derived from [⁶⁸Ga]Ga-NeoB diagnosis to assess the presence of GRPR in the tumor tissue and monitor antitumor treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41181-021-00137-w.

Entanglement Transition in a Monitored Free-Fermion Chain: From Extended Criticality to Area Law

We analyze the quantum trajectory dynamics of free fermions subject to continuous monitoring. For weak monitoring, we identify a novel dynamical regime of subextensive entanglement growth, reminiscent of a critical phase with an emergent conformal invariance. For strong monitoring, however, the dynamics favors a transition into a quantum Zeno-like area-law regime. Close to the critical point, we observe logarithmic finite size corrections, indicating a Berezinskii-Kosterlitz-Thouless mechanism underlying the transition. This uncovers an unconventional entanglement transition in an elementary, physically realistic model for weak continuous measurements. In addition, we demonstrate that the measurement aspect in the dynamics is crucial for whether or not a phase transition takes place.

Observation of Beam Spin Asymmetries in the Process ep→e^{'}π^{+}π^{-}X with CLAS12

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function e(x), which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function G_{1}^{⊥}. A clear sign change is observed around the ρ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark.

Photoproduction of the f_{2}(1270) Meson Using the CLAS Detector

The quark structure of the f_{2}(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq[over ¯]) resonance with quantum numbers J^{PC}=2^{++}. Recently, it was proposed that the f_{2}(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π^{+}π^{-}, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π^{0}π^{0}p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f_{2}(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.

Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs

A first measurement of the longitudinal beam spin asymmetry A_{LU} in the semi-inclusive electroproduction of pairs of charged pions is reported. A_{LU} is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A_{LU}^{sinϕ_{R}} moments are extracted for the kinematic variables of interest in the valence quark region. The understanding of dihadron production is essential for the interpretation of observables in single-hadron production in semi-inclusive DIS, and pioneering measurements of single-spin asymmetries in dihadron production open a new avenue in studies of QCD dynamics.

Extraction of Beam-Spin Asymmetries from the Hard Exclusive π^{+} Channel off Protons in a Wide Range of Kinematics

We have measured beam-spin asymmetries to extract the sinϕ moment A_{LU}^{sinϕ} from the hard exclusive e[over →]p→e^{'}nπ^{+} reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The A_{LU}^{sinϕ} moment has been measured up to 6.6  GeV^{2} in -t, covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found A_{LU}^{sinϕ} to be negative, while a sign change was observed near 90° in the center of mass. The unique results presented in this Letter will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks.

Response of advanced HCC to pembrolizumab and lenvatinib combination therapy despite monotherapy failure

In recent years, immune checkpoint inhibitors (ICIs) were successfully introduced to cancer therapy, and these drugs have already become essential for the treatment of various noncurable tumors. However, monotherapy in advanced hepatocellular carcinoma (aHCC) failed to show statistically significant improvement.Recently, the combination of atezolizumab and bevacizumab demonstrated efficacy of combining ICI and VEGF inhibition, further substantiating previous data on synergistic mechanisms among respective substance classes.As TKI treatment is currently standard of care for aHCC, and ICIs are approved by the FDA and available in many areas of the world, numerous patients may have been treated with monotherapy of those drugs. However, it remains unclear if failure to monotherapy has an impact on combination therapy. We therefore report a patient well responding to combination therapy despite previous failures to TKI and ICI monotherapy.

Topological Field Theory Far from Equilibrium

The observable properties of topological quantum matter are often described by topological field theories. Here, we demonstrate that this principle extends beyond thermal equilibrium. To this end, we construct a model of two-dimensional driven open dynamics with a Chern insulator steady state. Within a Keldysh field theory approach, we show that under mild assumptions-particle number conservation and purity of the stationary state-an abelian Chern-Simons theory describes its response to external perturbations. As a corollary, we predict chiral edge modes stabilized by a dissipative bulk.

Long-term results of selective internal radioembolization (SIRT) to control progressive liver metastases of gastro-intestinal stromal tumors (GIST) beyond treatment with tyrosine kinase inhibitors (TKI)

11538

Background: Liver and peritoneum are the main area of metastatic spread in GIST. Liver resection does not play a role for hepatic metastases in comparison to f.e. colorectal cancer. If hepatic metastases are the only or major area of tumor progression and are resistant to available TKIs due to a missing mutation in KIT/PDGFRA/SDH ( ‘wildtype’) or after treatment with 1st/2nd/3rd/4th line therapy, interventional radioembolization with yttrium-90 (90Y) microspheres are promising treatment options, as radiation doses as high as 200Gy can be applied locally. We analyzed the long-term results of SIRT with respect to hepatic-progression-free survival (HEP-PFS) in a consecutive cohort of patients.. Methods: From 1/2008 to 1/2018, 25 pts (12f, 13m) with biopsy proven liver metastases of GIST which were the only (n = 13) or the dominant site of progression (n = 12) were treated by SIRT. Median age at GIST diagnosis had been 51.8 yrs and when receiving SIRT was 57.6yrs (range, 18–75yrs). The mutational status was ‘wildtype’ (n = 7, 2 NF-1), exon 11 (n = 7), exon 11+2nd mutation (n = 6), exon 9 (n = 3), exon 9+2ndmut (n = 1), and, exon 13 (n = 1). All patients except of two had prior TKI therapy: 1 line n = 3, 2 lines n = 11, 3-4 lines n = 9. Follow-up after SIRT was done via dynamic MRI and contrast-enhanced (CE)-CT, the median follow-up is 30.6 mos (range, 12-100mos) and all patients were followed until death. Results: The median hepatic-progression free survival (HEP-PFS) after SIRT was 17 months (range, 5-53+, 95%CI 11.8-22.1 mos). Of the patients with concomitant extrahepatic disease, the extraHEP-PFS was median 10 months. Twelve patients received next-line TKI therapy for progressive extrahepatic disease, whereas six patients required this for progressive liver metastases. When comparing the results according to the mutational status, patients with a ‘wildtype’ tumor showed a better median HEP-PFS of 19 mos (range, 12-53+, 95%CI 16.7-21.2 mos.) in comparison to KIT exon 9/11/13 mutated patients with only 14 months (range, 4-34 mos., 95%CI 6.5-21.4 mos), p < 0.11 (Wilcoxon). Conclusions: 90Y radioembolization (SIRT) offers a safe and effective treatment for patients with liver metastases of GISTs being the dominant site of tumor progression and with no drug treatment options available. In patients known to have no mutation in KIT/PDGFRA (wt, also NF-1 associated) it looks whether the results might be even more promising and SIRT could be used in early treatment lines.

A review of flux identification methods for models of sedimentation

Most models of sedimentation contain the nonlinear hindered-settling flux function. If one assumes ideal conditions and no compression, then there exist several theoretically possible ways of identifying a large portion of the flux function from only one experiment by means of formulas derived from the theory of solutions of partial differential equations. Previously used identification methods and recently published such, which are based on utilizing conical vessels or centrifuges, are reviewed and compared with synthetic data (simulated experiments). This means that the identification methods are evaluated from a theoretical viewpoint without experimental errors or difficulties. The main contribution of the recent methods reviewed is that they, in theory, can identify a large portion of the flux function from a single experiment, in contrast to the traditional method that provides one point on the flux curve from each test. The new methods lay the foundation of rapid flux identification; however, experimental procedures need to be elaborated.

Exploring the Structure of the Bound Proton with Deeply Virtual Compton Scattering

In the past two decades, deeply virtual Compton scattering of electrons has been successfully used to advance our knowledge of the partonic structure of the free proton and investigate correlations between the transverse position and the longitudinal momentum of quarks inside the nucleon. Meanwhile, the structure of bound nucleons in nuclei has been studied in inclusive deep-inelastic lepton scattering experiments off nuclear targets, showing a significant difference in longitudinal momentum distribution of quarks inside the bound nucleon, known as the EMC effect. In this Letter, we report the first beam spin asymmetry (BSA) measurement of exclusive deeply virtual Compton scattering off a proton bound in ^{4}He. The data used here were accumulated using a 6 GeV longitudinally polarized electron beam incident on a pressurized ^{4}He gaseous target placed within the CLAS spectrometer in Hall-B at the Thomas Jefferson National Accelerator Facility. The azimuthal angle (ϕ) dependence of the BSA was studied in a wide range of virtual photon and scattered proton kinematics. The Q^{2}, x_{B}, and t dependencies of the BSA on the bound proton are compared with those on the free proton. In the whole kinematical region of our measurements, the BSA on the bound proton is smaller by 20% to 40%, indicating possible medium modification of its partonic structure.

Direct Observation of Proton-Neutron Short-Range Correlation Dominance in Heavy Nuclei

We measured the triple coincidence A(e,e^{'}np) and A(e,e^{'}pp) reactions on carbon, aluminum, iron, and lead targets at Q^{2}>1.5  (GeV/c)^{2}, x_{B}>1.1 and missing momentum >400  MeV/c. This was the first direct measurement of both proton-proton (pp) and neutron-proton (np) short-range correlated (SRC) pair knockout from heavy asymmetric nuclei. For all measured nuclei, the average proton-proton (pp) to neutron-proton (np) reduced cross-section ratio is about 6%, in agreement with previous indirect measurements. Correcting for single-charge exchange effects decreased the SRC pairs ratio to ∼3%, which is lower than previous results. Comparisons to theoretical generalized contact formalism (GCF) cross-section calculations show good agreement using both phenomenological and chiral nucleon-nucleon potentials, favoring a lower pp to np pair ratio. The ability of the GCF calculation to describe the experimental data using either phenomenological or chiral potentials suggests possible reduction of scale and scheme dependence in cross-section ratios. Our results also support the high-resolution description of high-momentum states being predominantly due to nucleons in SRC pairs.

First Measurements of the Double-Polarization Observables F, P, and H in ω Photoproduction off Transversely Polarized Protons in the N^{*} Resonance Region

First measurements of double-polarization observables in ω photoproduction off the proton are presented using transverse target polarization and data from the CEBAF Large Acceptance Spectrometer (CLAS) FROST experiment at Jefferson Lab. The beam-target asymmetry F has been measured using circularly polarized, tagged photons in the energy range 1200-2700 MeV, and the beam-target asymmetries H and P have been measured using linearly polarized, tagged photons in the energy range 1200-2000 MeV. These measurements significantly increase the database on polarization observables. The results are included in two partial-wave analyses and reveal significant contributions from several nucleon (N^{*}) resonances. In particular, contributions from new N^{*} resonances listed in the Review of Particle Properties are observed, which aid in reaching the goal of mapping out the nucleon resonance spectrum.

Orthogonality Catastrophe in Dissipative Quantum Many-Body Systems

We present an analog of the phenomenon of orthogonality catastrophe in quantum many-body systems subject to a local dissipative impurity. We show that the fidelity F(t), giving a measure for distance of the time-evolved state from the initial one, displays a universal scaling form F(t)∝t^{θ}e^{-γt}, when the system supports long-range correlations, in a fashion reminiscent of traditional instances of orthogonality catastrophe in condensed matter. An exponential falloff at rate γ signals the onset of environmental decoherence, which is critically slowed down by the additional algebraic contribution to the fidelity. This picture is derived within a second-order cumulant expansion suited for Liouvillian dynamics, and substantiated for the one-dimensional transverse field quantum Ising model subject to a local dephasing jump operator, as well as for XY and XX quantum spin chains, and for the two-dimensional Bose gas deep in the superfluid phase with local particle heating. Our results hint that local sources of dissipation can be used to inspect real-time correlations and to induce a delay of decoherence in open quantum many-body systems.

Center of Mass Motion of Short-Range Correlated Nucleon Pairs studied via the A(e,e^{'}pp) Reaction

Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170  MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field nucleons in specific quantum states.

Modeling sphere dynamics in blood vessels for SIRT pre-planning - To fathom the potential and limitations

For selective internal radiation therapy (SIRT) the calculation of the 3D distribution of spheres based on individual blood flow properties is still an open and relevant research question. The purpose of this work is to develop and analyze a new treatment planning method for SIRT to calculate the absorbed dose distribution. For this intention, flow dynamics of the SIRT-spheres inside the blood vessels was simulated. The challenge is treatment planning solely using high-resolution imaging data available before treatment. The resolution required to reliably predict the sphere distribution and hence the dose was investigated. For this purpose, arteries of the liver were segmented from a contrast-enhanced angiographic CT. Due to the limited resolution of the given CT, smaller vessels were generated via a vessel model. A combined 1D/3D-flow simulation model was implemented to simulate the final 3D distribution of spheres and dose. Results were evaluated against experimental data from Y90-PET. Analysis showed that the resolution of the vessels within the angiographic CT of about 0.5mm should be improved to a limit of about 150μm to reach a reliable prediction.

Efimov States of Strongly Interacting Photons

We demonstrate the emergence of universal Efimov physics for interacting photons in cold gases of Rydberg atoms. We consider the behavior of three photons injected into the gas in their propagating frame, where a paraxial approximation allows us to consider them as massive particles. In contrast to atoms and nuclei, the photons have a large anisotropy between their longitudinal mass, arising from dispersion, and their transverse mass, arising from diffraction. Nevertheless, we show that, in suitably rescaled coordinates, the effective interactions become dominated by s-wave scattering near threshold and, as a result, give rise to an Efimov effect near unitarity. We show that the three-body loss of these Efimov trimers can be strongly suppressed and determine conditions under which these states are observable in current experiments. These effects can be naturally extended to probe few-body universality beyond three bodies, as well as the role of Efimov physics in the nonequilibrium, many-body regime.

Renal Denervation in Patients with Resistant Hypertension-Assessment by 3T Renal 23Na-MRI: Preliminary Results

BACKGROUND/AIM

Renal denervation (RDN) has been considered a promising therapy option for patients suffering from therapy-resistant hypertension. Besides, in blood-pressure regularization, the kidneys play a fundamental role in sodium ((23)Na) homeostasis. This study assesses the effect of RDN on renal (23)Na concentration using (23)Na magnetic resonance imaging (MRI).

PATIENTS AND METHODS

Two patients with therapy-resistant hypertension underwent RDN. (23)Na-MRI, (1)H-MRI, including diffusion weighted imaging (DWI), as well as endothelial dysfunction assessment, were performed 1 day prior, as well as 1, 30 and 90 days after RDN.

RESULTS

The renal corticomedullary (23)Na gradient did not change after RDN for all time points. Additionally, functional imaging and retinal vessel parameters were not influenced by RDN. Results regarding blood pressure changes and arterial stiffness, as well as patients' clinical outcome, were heterogeneous.

CONCLUSION

RDN does not seem to alter renal (23)Na concentration gradients, as measured by MRI.

Keldysh field theory for driven open quantum systems

Recent experimental developments in diverse areas-ranging from cold atomic gases to light-driven semiconductors to microcavity arrays-move systems into the focus which are located on the interface of quantum optics, many-body physics and statistical mechanics. They share in common that coherent and driven-dissipative quantum dynamics occur on an equal footing, creating genuine non-equilibrium scenarios without immediate counterpart in equilibrium condensed matter physics. This concerns both their non-thermal stationary states and their many-body time evolution. It is a challenge to theory to identify novel instances of universal emergent macroscopic phenomena, which are tied unambiguously and in an observable way to the microscopic drive conditions. In this review, we discuss some recent results in this direction. Moreover, we provide a systematic introduction to the open system Keldysh functional integral approach, which is the proper technical tool to accomplish a merger of quantum optics and many-body physics, and leverages the power of modern quantum field theory to driven open quantum systems.

Steady-state analysis of activated sludge processes with a settler model including sludge compression

A reduced model of a completely stirred-tank bioreactor coupled to a settling tank with recycle is analyzed in its steady states. In the reactor, the concentrations of one dominant particulate biomass and one soluble substrate component are modelled. While the biomass decay rate is assumed to be constant, growth kinetics can depend on both substrate and biomass concentrations, and optionally model substrate inhibition. Compressive and hindered settling phenomena are included using the Bürger-Diehl settler model, which consists of a partial differential equation. Steady-state solutions of this partial differential equation are obtained from an ordinary differential equation, making steady-state analysis of the entire plant difficult. A key result showing that the ordinary differential equation can be replaced with an approximate algebraic equation simplifies model analysis. This algebraic equation takes the location of the sludge-blanket during normal operation into account, allowing for the limiting flux capacity caused by compressive settling to easily be included in the steady-state mass balance equations for the entire plant system. This novel approach grants the possibility of more realistic solutions than other previously published reduced models, comprised of yet simpler settler assumptions. The steady-state concentrations, solids residence time, and the wastage flow ratio are functions of the recycle ratio. Solutions are shown for various growth kinetics; with different values of biomass decay rate, influent volumetric flow, and substrate concentration.

The role of clinical evidence in emergent therapies: an empirical study on femoropopliteal stent-angioplasty in Europe

RATIONALE, AIMS AND OBJECTIVE

A delayed availability of clinical evidence in rapidly emerging therapies is considered a major problem. In this study, we examined whether evidence from clinical studies has influenced the therapy of a major disease in industrial countries, peripheral arterial disease (PAD), using novel femoropopliteal stent-angioplasty.

METHOD

This analysis of retrospective time series data uses multivariate linear regression to investigate associations between published clinical evidence on femoropopliteal stent-angioplasty from Q3/2004 to Q4/2010 and the demand for femoropopliteal stents in Germany, France, Italy and the UK between Q1/2005 and Q4/2010, controlling for the prevalence of PAD risk factors, cardiovascular drug demand, reimbursement of health care providers for stent implantation, stent selling prices of manufacturers and economic indicators.

RESULTS

We did not observe any association of published clinical evidence with femoropopliteal stent demand in Germany, France, Italy and the UK, while we observed such associations for varying control variables at different time lags respectively.

CONCLUSION

We observed no association between published clinical evidence of femoropopliteal stent-angioplasty and its use in any of the four countries. The country-specific context and practice-related variables at a centre and individual doctor level may have limited the role of published clinical evidence in emerging femoropopliteal stent-angioplasty. More research is needed at this context, centre and individual level.

Abstract 3598: Selective internal radiation (SIRT) is most effective when comparing local treatment to control progressive liver metastases of gastro-intestinal stromal tumors beyond treatment with tyrosine kinase inhibitors

Objective: The liver and the peritoneum are the main area of metastatic spread in gastrointestinal stromal tumors (GIST). Liver surgery plays a minor role for hepatic metastases in comparison to f.e. colorectal cancer. However, once the metastases are resistant to 1st line TKI, surgery, 2nd line therapy, interventional ablation techniques like RFA or selective internal radiation therapy (SIRT) are treatment options. We were interested to analyze the contribution of the different modalities in controlling hepatic progression.

Methods: 731 pts with biopsy proven GIST were followed since 2004 (median follow-up 43.6 months); data were prospectively documented. There were 337 males (46.1%) and 101 (13.8%) pts. presented with M1 disease initially. Of the remaining 630 pts, 358 pts (56.8%) developed tumor recurrence after a median time interval of 22 months. 312/358 pts (87%) developed metastases within the abdomen: liver n = 96, peritoneal n = 97, liver+peritoneal n = 78, locoregional n = 10, locoreg.+hep/per n = 21. Imatinib was the initial treatment in all patients with M1 disease.

Results: Out of 205 patients with liver metastases, 118 remained controlled by drug therapy or showed multi-site progression. In the remaining 87 pts., 26 pts each underwent liver resection or 2nd/3rd line drug therapy (sunitinib, regorafenib), 22 pts had RFA and 13 pts were treated by SIRT. Follow-up was done via dynamic MRI and contrast-enhanced (CE)-CT. The median hepatic-progression free survival (H-PFS) was 15.9 months (4-29) after SIRT (with 3 CR, 6 PR), however, only 5.6 (range, 2 - 13) months after 2nd line drug, 8.2 (3-15) months after surgery, and 7.7 (5-14) months after RFA, p&lt;0.02.

Conclusion: 90Y radiation loaded particles (SIRT) provides the best hepatic progression free survival when compared to 2nd line drugs, RFA or even surgery in imatinib resistant GIST liver metastases. The effect could be mediated by eliminating small (subclinical, micro-) metastases. In patients known to have a GIST resistant to known TKIs, such as wildtype (non-KIT, non-PDGFRA mutated f.e. NF1-associated) lesions, SIRT could be used in earlier treatment lines.

Citation Format: Peter Hohenberger, Nils Rathmann, Franka Menge, Maliha Sadick, Stefan Schönberg, Steffen Diehl. Selective internal radiation (SIRT) is most effective when comparing local treatment to control progressive liver metastases of gastro-intestinal stromal tumors beyond treatment with tyrosine kinase inhibitors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3598. doi:10.1158/1538-7445.AM2015-3598

Impact on sludge inventory and control strategies using the benchmark simulation model no. 1 with the Bürger-Diehl settler model

An improved one-dimensional (1-D) model for the secondary clarifier, i.e. the Bürger-Diehl model, was recently presented. The decisive difference to traditional layer models is that every detail of the implementation is in accordance with the theory of partial differential equations. The Bürger-Diehl model allows accounting for hindered and compressive settling as well as inlet dispersion. In this contribution, the impact of specific features of the Bürger-Diehl model on settler underflow concentration predictions, plant sludge inventory and mixed liquor suspended solids based control actions are investigated by using the benchmark simulation model no. 1. The numerical results show that the Bürger-Diehl model allows for more realistic predictions of the underflow sludge concentration, which is essential for more accurate wet weather modelling and sludge waste predictions. The choice of secondary settler model clearly has a profound impact on the operation and control of the entire treatment plant and it is recommended to use the Bürger-Diehl model as of now in any wastewater treatment plant modelling effort.

Implementation of the Dicke lattice model in hybrid quantum system arrays

Generalized Dicke models can be implemented in hybrid quantum systems built from ensembles of nitrogen-vacancy (NV) centers in diamond coupled to superconducting microwave cavities. By engineering cavity assisted Raman transitions between two spin states of the NV defect, a fully tunable model for collective light-matter interactions in the ultrastrong coupling limit can be obtained. Our analysis of the resulting nonequilibrium phases for a single cavity and for coupled cavity arrays shows that different superradiant phase transitions can be observed using existing experimental technologies, even in the presence of large inhomogeneous broadening of the spin ensemble. The phase diagram of the Dicke lattice model displays distinct features induced by dissipation, which can serve as a genuine experimental signature for phase transitions in driven open quantum systems.

A one-dimensional moving-boundary model for tubulin-driven axonal growth

A one-dimensional continuum-mechanical model of axonal elongation due to assembly of tubulin dimers in the growth cone is presented. The conservation of mass leads to a coupled system of three differential equations. A partial differential equation models the dynamic and the spatial behaviour of the concentration of tubulin that is transported along the axon from the soma to the growth cone. Two ordinary differential equations describe the time-variation of the concentration of free tubulin in the growth cone and the speed of elongation. All steady-state solutions of the model are categorized. Given a set of the biological parameter values, it is shown how one easily can infer whether there exist zero, one or two steady-state solutions and directly determine the possible steady-state lengths of the axon. Explicit expressions are given for each stationary concentration distribution. It is thereby easy to examine the influence of each biological parameter on a steady state. Numerical simulations indicate that when there exist two steady states, the one with shorter axon length is unstable and the longer is stable. Another result is that, for nominal parameter values extracted from the literature, in a large portion of a fully grown axon the concentration of free tubulin is lower than both concentrations in the soma and in the growth cone.

Constrained dynamics via the Zeno effect in quantum simulation: implementing non-Abelian lattice gauge theories with cold atoms

We show how engineered classical noise can be used to generate constrained Hamiltonian dynamics in atomic quantum simulators of many-body systems, taking advantage of the continuous Zeno effect. After discussing the general theoretical framework, we focus on applications in the context of lattice gauge theories, where imposing exotic, quasilocal constraints is usually challenging. We demonstrate the effectiveness of the scheme for both Abelian and non-Abelian gauge theories, and discuss how engineering dissipative constraints substitutes complicated, nonlocal interaction patterns by global coupling to laser fields.

Dynamical critical phenomena in driven-dissipative systems

We explore the nature of the Bose condensation transition in driven open quantum systems, such as exciton-polariton condensates. Using a functional renormalization group approach formulated in the Keldysh framework, we characterize the dynamical critical behavior that governs decoherence and an effective thermalization of the low frequency dynamics. We identify a critical exponent special to the driven system, showing that it defines a new dynamical universality class. Hence critical points in driven systems lie beyond the standard classification of equilibrium dynamical phase transitions. We show how the new critical exponent can be probed in experiments with driven cold atomic systems and exciton-polariton condensates.