To prospectively compare standard radiation therapy (RT) with an abbreviated course of RT in older patients with glioblastoma multiforme (GBM).
One hundred patients with GBM, age 60 years or older, ...were randomly assigned after surgery to receive either standard RT (60 Gy in 30 fractions over 6 weeks) or a shorter course of RT (40 Gy in 15 fractions over 3 weeks). The primary end point was overall survival. The secondary end points were proportionate survival at 6 months, health-related quality of life (HRQoL), and corticosteroid requirement. HRQoL was assessed using the Karnofsky performance status (KPS) and Functional Assessment of Cancer Therapy-Brain (FACT-Br).
All patients had died at the time of analysis. Overall survival times measured from randomization were similar at 5.1 months for standard RT versus 5.6 months for the shorter course (log-rank test, P =.57). The survival probabilities at 6 months were also similar at 44.7% for standard RT versus 41.7% for the shorter course (lower-bound 95% CI, -13.7). KPS scores varied markedly but were not significantly different between the two groups (Wilcoxon test, P =.63). Low completion rates of the FACT-Br (45%) precluded meaningful comparisons between the two groups. Of patients completing RT as planned, 49% of patients (standard RT) versus 23% required an increase in posttreatment corticosteroid dosage (chi(2) test, P =.02).
There is no difference in survival between patients receiving standard RT or short-course RT. In view of the similar KPS scores, decreased increment in corticosteroid requirement, and reduced treatment time, the abbreviated course of RT seems to be a reasonable treatment option for older patients with GBM.
We use our recent electric dipole moment (EDM) measurement data to constrain the possibility that the HfF^{+} EDM oscillates in time due to interactions with candidate dark matter axionlike particles ...(ALPs). We employ a Bayesian analysis method which accounts for both the look-elsewhere effect and the uncertainties associated with stochastic density fluctuations in the ALP field. We find no evidence of an oscillating EDM over a range spanning from 27 nHz to 400 mHz, and we use this result to constrain the ALP-gluon coupling over the mass range 10^{-22}-10^{-15} eV. This is the first laboratory constraint on the ALP-gluon coupling in the 10^{-17}-10^{-15} eV range, and the first laboratory constraint to properly account for the stochastic nature of the ALP field.
Measurement-based quantum error correction relies on the ability to determine the state of a subset of qubits (ancillas) within a processor without revealing or disturbing the state of the remaining ...qubits. Among neutral-atom-based platforms, a scalable, high-fidelity approach to midcircuit measurement that retains the ancilla qubits in a state suitable for future operations has not yet been demonstrated. In this work, we perform maging using a narrow-linewidth transition in an array of tweezer-confined ^{171}Yb atoms to demonstrate nondestructive state-selective and site-selective detection. By applying site-specific light shifts, selected atoms within the array can be hidden from imaging light, which allows a subset of qubits to be measured while causing only percent-level errors on the remaining qubits. As a proof-of-principle demonstration of conditional operations based on the results of the midcircuit measurements, and of our ability to reuse ancilla qubits, we perform conditional refilling of ancilla sites to correct for occasional atom loss, while maintaining the coherence of data qubits. Looking toward true continuous operation, we demonstrate loading of a magneto-optical trap with a minimal degree of qubit decoherence.
Understanding the quantum dynamics of strongly interacting fermions is a problem relevant to diverse forms of matter, including high-temperature superconductors, neutron stars, and quark-gluon ...plasma. An appealing benchmark is offered by cold atomic gases in the unitary limit of strong interactions. Here, we study the dynamics of a transversely magnetized unitary Fermi gas in an inhomogeneous magnetic field. We observe the demagnetization of the gas, caused by diffusive spin transport. At low temperatures, the diffusion constant saturates to the conjectured quantum-mechanical lower bound ≃ ħ/m, where m is the particle mass. The development of pair correlations, indicating the transformation of the initially noninteracting gas toward a unitary spin mixture, is observed by measuring Tan's contact parameter.
Assembling and maintaining large arrays of individually addressable atoms is a key requirement for continued scaling of neutral-atom-based quantum computers and simulators. In this work, we ...demonstrate a new paradigm for assembly of atomic arrays, based on a synergistic combination of optical tweezers and cavity-enhanced optical lattices, and the incremental filling of a target array from a repetitively filled reservoir. In this protocol, the tweezers provide microscopic rearrangement of atoms, while the cavity-enhanced lattices enable the creation of large numbers of optical traps with sufficient depth for rapid low-loss imaging of atoms. We apply this protocol to demonstrate near-deterministic filling (99% per-site occupancy) of 1225-site arrays of optical traps. Because the reservoir is repeatedly filled with fresh atoms, the array can be maintained in a filled state indefinitely. We anticipate that this protocol will be compatible with mid-circuit reloading of atoms into a quantum processor, which will be a key capability for running large-scale error-corrected quantum computations whose durations exceed the lifetime of a single atom in the system.
Measurement-based quantum error correction relies on the ability to determine the state of a subset of qubits (ancillae) within a processor without revealing or disturbing the state of the remaining ...qubits. Among neutral-atom based platforms, a scalable, high-fidelity approach to mid-circuit measurement that retains the ancilla qubits in a state suitable for future operations has not yet been demonstrated. In this work, we perform imaging using a narrow-linewidth transition in an array of tweezer-confined \(^{171}\)Yb atoms to demonstrate nondestructive state-selective and site-selective detection. By applying site-specific light shifts, selected atoms within the array can be hidden from imaging light, which allows a subset of qubits to be measured while causing only percent-level errors on the remaining qubits. As a proof-of-principle demonstration of conditional operations based on the results of the mid-circuit measurements, and of our ability to reuse ancilla qubits, we perform conditional refilling of ancilla sites to correct for occasional atom loss, while maintaining the coherence of data qubits. Looking towards true continuous operation, we demonstrate loading of a magneto-optical trap with a minimal degree of qubit decoherence.
Treatment for newly diagnosed anaplastic oligodendroglial tumors is controversial. Radiotherapy (RT) alone and in combination with chemotherapy (CT) are the most well studied strategies. However, CT ...alone is often advocated, especially in cases with 1p19q codeletion. We retrospectively identified 1013 adults diagnosed from 1981-2007 treated initially with RT alone (n = 200), CT + RT (n = 528), CT alone (n = 201), or other strategies (n = 84). Median overall survival (OS) was 6.3 years and time to progression (TTP) was 3.1 years. 1p19q codeletion correlated with longer OS and TTP than no 1p or 19q deletion. In codeleted cases, median TTP was longer following CT + RT (7.2 y) than following CT (3.9 y, P = .003) or RT (2.5 y, P < .001) alone but without improved OS; median TTP was longer following treatment with PCV alone than temozolomide alone (7.6 vs. 3.3 y, P = .019). In cases with no deletion, median TTP was longer following CT + RT (3.1 y) than CT (0.9 y, P = .0124) or RT (1.1 y, P < .0001) alone; OS also favored CT + RT (median 5.0 y) over CT (2.2 y, P = .02) or RT (1.9 y, P < .0001) alone. In codeleted cases, CT alone did not appear to shorten OS in comparison with CT + RT, and PCV appeared to offer longer disease control than temozolomide but without a clear survival advantage. Combined CT + RT led to longer disease control and survival than did CT or RT alone in cases with no 1p19q deletion. Ongoing trials will address these issues prospectively.
IDH1 mutation is the earliest genetic alteration in low-grade gliomas (LGGs), but its role in tumor recurrence is unclear.Mutant IDH1 drives overproduction of the oncometabolite D-2-hydroxyglutarate ...(2HG) and a CpG island (CGI) hypermethylation phenotype (G-CIMP). To investigate the role of mutant IDH1 at recurrence, we performed a longitudinal analysis of 50 IDH1 mutant LGGs. We discovered six cases with copy number alterations (CNAs) at the IDH1 locus at recurrence. Deletion or amplification of IDH1 was followed by clonal expansion and recurrence at a higher grade. Successful cultures derived from IDH1 mutant, but not IDH1 wild type, gliomas systematically deleted IDH1 in vitro and in vivo, further suggestive of selection against the heterozygous mutant state as tumors progress. Tumors and cultures with IDH1 CNA had decreased 2HG, maintenance of G-CIMP, and DNA methylation reprogramming outside CGI. Thus, while IDH1 mutation initiates gliomagenesis, in some patients mutant IDH1 and 2HG are not required for later clonal expansions.
The European Organisation for Research and Treatment of Cancer and National Cancer Institute of Canada trial on temozolomide (TMZ) and radiotherapy (RT) in glioblastoma (GBM) has demonstrated that ...the combination of TMZ and RT conferred a significant and meaningful survival advantage compared with RT alone. We evaluated in this trial whether the recursive partitioning analysis (RPA) retains its overall prognostic value and what the benefit of the combined modality is in each RPA class.
Five hundred seventy-three patients with newly diagnosed GBM were randomly assigned to standard postoperative RT or to the same RT with concomitant TMZ followed by adjuvant TMZ. The primary end point was overall survival. The European Organisation for Research and Treatment of Cancer RPA used accounts for age, WHO performance status, extent of surgery, and the Mini-Mental Status Examination.
Overall survival was statistically different among RPA classes III, IV, and V, with median survival times of 17, 15, and 10 months, respectively, and 2-year survival rates of 32%, 19%, and 11%, respectively (P < .0001). Survival with combined TMZ/RT was higher in RPA class III, with 21 months median survival time and a 43% 2-year survival rate, versus 15 months and 20% for RT alone (P = .006). In RPA class IV, the survival advantage remained significant, with median survival times of 16 v 13 months, respectively, and 2-year survival rates of 28% v 11%, respectively (P = .0001). In RPA class V, however, the survival advantage of RT/TMZ was of borderline significance (P = .054).
RPA retains its prognostic significance overall as well as in patients receiving RT with or without TMZ for newly diagnosed GBM, particularly in classes III and IV.
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