Error mitigation enables PET radiomic cancer characterization on quantum computers.

BACKGROUND: Cancer is a leading cause of death worldwide. While routine diagnosis of cancer is performed mainly with biopsy sampling, it is suboptimal to accurately characterize tumor heterogeneity. Positron emission tomography (PET)-driven radiomic research has demonstrated promising results when predicting clinical endpoints. This study aimed to investigate the added value of quantum machine learning both in simulator and in real quantum computers utilizing error mitigation techniques to predict clinical endpoints in various PET cancer patients. METHODS: Previously published PET radiomics datasets including 11C-MET PET glioma, 68GA-PSMA-11 PET prostate and lung 18F-FDG PET with 3-year survival, low-vs-high Gleason risk and 2-year survival as clinical endpoints respectively were utilized in this study. Redundancy reduction with 0.7, 0.8, and 0.9 Spearman rank thresholds (SRT), followed by selecting 8 and 16 features from all cohorts, was performed, resulting in 18 dataset variants. Quantum advantage was estimated by Geometric Difference (GDQ) score in each dataset variant. Five classic machine learning (CML) and their quantum versions (QML) were trained and tested in simulator environments across the dataset variants. Quantum circuit optimization and error mitigation were performed, followed by training and testing selected QML methods on the 21-qubit IonQ Aria quantum computer. Predictive performances were estimated by test balanced accuracy (BACC) values. RESULTS: On average, QML outperformed CML in simulator environments with 16-features (BACC 70% and 69%, respectively), while with 8-features, CML outperformed QML with + 1%. The highest average QML advantage was + 4%. The GDQ scores were ≤ 1.0 in all the 8-feature cases, while they were > 1.0 when QML outperformed CML in 9 out of 11 cases. The test BACC of selected QML methods and datasets in the IonQ device without error mitigation (EM) were 69.94% BACC, while EM increased test BACC to 75.66% (76.77% in noiseless simulators). CONCLUSIONS: We demonstrated that with error mitigation, quantum advantage can be achieved in real existing quantum computers when predicting clinical endpoints in clinically relevant PET cancer cohorts. Quantum advantage can already be achieved in simulator environments in these cohorts when relying on QML.

Unilateral bicep curl hemodynamics: Low-pressure continuous vs high-pressure intermittent blood flow restriction.

Light-load exercise training with blood flow restriction (BFR) increases muscle strength and size. However, the hemodynamics of BFR exercise appear elevated compared with non-BFR exercise. This questions the suitability of BFR in special/clinical populations. Nevertheless, hemodynamics of standard prescription protocols for BFR and traditional heavy-load exercise have not been compared. We investigated the hemodynamics of two common BFR exercise methods and two traditional resistance exercises. Twelve young males completed four unilateral elbow flexion exercise trials in a balanced, randomized crossover design: (a) heavy load [HL; 80% one-repetition maximum (1-RM)]; (b) light load (LL; 20% 1-RM); and two other light-load trials with BFR applied (c) continuously at 80% resting systolic blood pressure (BFR-C) or (d) intermittently at 130% resting systolic blood pressure (BFR-I). Hemodynamics were measured at baseline, during exercise, and for 60-min post-exercise. Exercising heart rate, blood pressure, cardiac output, and rate-pressure product were significantly greater for HL and BFR-I compared with LL. The magnitude of hemodynamic stress for BFR-C was between that of HL and LL. These data show reduced hemodynamics for continuous low-pressure BFR exercise compared with intermittent high-pressure BFR in young healthy populations. BFR remains a potentially viable method to improve muscle mass and strength in special/clinical populations.

Clinical data classification with noisy intermediate scale quantum computers.

Quantum machine learning has experienced significant progress in both software and hardware development in the recent years and has emerged as an applicable area of near-term quantum computers. In this work, we investigate the feasibility of utilizing quantum machine learning (QML) on real clinical datasets. We propose two QML algorithms for data classification on IBM quantum hardware: a quantum distance classifier (qDS) and a simplified quantum-kernel support vector machine (sqKSVM). We utilize these different methods using the linear time quantum data encoding technique ([Formula: see text]) for embedding classical data into quantum states and estimating the inner product on the 15-qubit IBMQ Melbourne quantum computer. We match the predictive performance of our QML approaches with prior QML methods and with their classical counterpart algorithms for three open-access clinical datasets. Our results imply that the qDS in small sample and feature count datasets outperforms kernel-based methods. In contrast, quantum kernel approaches outperform qDS in high sample and feature count datasets. We demonstrate that the [Formula: see text] encoding increases predictive performance with up to + 2% area under the receiver operator characteristics curve across all quantum machine learning approaches, thus, making it ideal for machine learning tasks executed in Noisy Intermediate Scale Quantum computers.

Postnatal intracerebroventricular administrations of NGF alter spatial memory in adulthood.

The present work assessed the effects of intracerebroventricular injections (2x5 mg/2.5 ml) of recombined human nerve growth factor (rhNGF) at postnatal days 2 and 3 upon the development of spatial learning capacities in rats. The treated rats were trained at the age of 22 days to escape onto an invisible platform at a fixed position in space in a Morris navigation task. For half of the subjects, the training position was also cued, a procedure aimed at facilitating escape and reducing attention to the distant spatial cues. At the age of 2 months all the rats were retrained in the same task. Treatment effects were found in both immature and adult rats. The injection of NGF induced a slight alteration of the immature rats' performance. In contrast, a marked impairment of spatial abilities was shown in the 2-month-old rats. The most consistent effects were a significant increase in the escape latency and a decrease bias towards the training platform area during probe trials. The reduction of spatial memory was particularly marked if the subjects had been trained in a cued condition. Taken together, these experiments reveal that an acute pharmacological treatment that leads to transient modifications during early development might induce a behavioural change long after treatment. Thus, the development and the maintenance of an accurate spatial representation are tightly related to the development of brain structures that could be altered by precocious NGF administrations.

Septal lesions impair the acquisition of a cued place navigation task: attentional or memory deficit?

These experiments were designed to analyze how medial septal lesions reducing the cholinergic innervation in the hippocampus might affect place learning. Rats with quisqualic lesions of the medial septal area (MS) were trained in a water maze and on a homing table where the escape position was located at a spatially fixed position and further indicated by a salient cue suspended above it. The lesioned rats were significantly impaired in reaching the cued escape platform during training. In addition rats, did not show any discrimination of the training sector during a probe trial in which no platform or cue was present. This impairment remained significant during further training in the absence of the cue. When the cued escape platform was located at an unpredictable spatial location, the MS-lesioned rats showed no deficit and spent more time under the cue than control rats during the probe trial. On the homing board, with a salient object in close proximity to the escape hole, the MS rats showed no deficit in escape latencies, although a significant reduction in spatial memory was observed. However, this was overcome by additional training in the absence of the cue. Under these conditions, rats with septal lesions were prone to develop a pure guidance strategy, whereas normal rats combined a guidance strategy with a memory of the escape position relative to more distant landmarks. The presence of a salient cue appeared to decrease attention to environmental landmarks, thus reducing spatial memory. These data confirm the general hypothesis that MS lesions reduce the capacity to rely on a representation of the relation between several landmarks with different salience.

Enhanced visuospatial memory following intracerebroventricular administration of nerve growth factor.

The present work assessed the effects of intracerebroventricular injections of rh recombined human nerve growth factor (rh NGF) (5 micrograms/2.5 microl) at postnatal days 12 and 13 upon the development of spatial learning capacities. The treated rats were trained at the age of 22 days to escape onto an invisible platform at a fixed position in space in a Morris navigation task. For half of the subjects, the training position was also cued, a procedure aimed at facilitating escape and at reducing attention to the distant spatial cues. Later, at the age of 6 months, all the rats were trained in a radial-arm maze task. Treatment effects were found in both immature and adult rats. The injection of NGF improved the performance in the Morris navigation task in both training conditions. There was a significant reduction in the escape latency and an increased bias toward the training platform quadrant during probe trials. The most consistent effect was the precocious development of an adult-like spatial memory. In the radial-arm maze, the NGF-treated rats made significantly fewer reentries than vehicle rats and this effect was particularly marked in the treated female rats. Taken together, these experiments reveal that the development and the maintenance of an accurate spatial representation are tightly related to the development of brain structures facilitated by the action of NGF. Moreover, these experiments demonstrate that an acute pharmacological treatment that leads to a transient modification in the choline acetyltransferase activity can induce a behavioral change long after the treatment.