Enhancing combinatorial optimization with classical and quantum generative models

Devising an efficient exploration of the search space is one of the key challenges in the design of combinatorial optimization algorithms. Here, we introduce the Generator-Enhanced Optimization (GEO) strategy: a framework that leverages any generative model (classical, quantum, or quantum-inspired) to solve optimization problems. We focus on a quantum-inspired version of GEO relying on tensor-network Born machines, and referred to hereafter as TN-GEO. To illustrate our results, we run these benchmarks in the context of the canonical cardinality-constrained portfolio optimization problem by constructing instances from the S&P 500 and several other financial stock indexes, and demonstrate how the generalization capabilities of these quantum-inspired generative models can provide real value in the context of an industrial application. We also comprehensively compare state-of-the-art algorithms and show that TN-GEO is among the best; a remarkable outcome given the solvers used in the comparison have been fine-tuned for decades in this real-world industrial application. Also, a promising step toward a practical advantage with quantum-inspired models and, subsequently, with quantum generative models.

Comparison of visual and passive acoustic estimates of beaked whale density off El Hierro, Canary Islands

Passive acoustic monitoring (PAM) offers considerable potential for density estimation of cryptic cetaceans, such as beaked whales. However, comparative studies on the accuracy of PAM density estimates from these species are lacking. Concurrent, low-cost drifting PAM, with SoundTraps suspended at 200 m depth, and land-based sightings, were conducted off the Canary Islands. Beaked whale density was estimated using a cue-count method, with click production rate and the probability of click detection derived from digital acoustic recording tags (DTags), and distance sampling techniques, adapted to fixed-point visual surveys. Of 32 870 detections obtained throughout 206 h of PAM recordings, 68% were classified as "certain" beaked whale clicks. Acoustic detection probability was 0.15 [coefficient variation (CV) 0.24] and click production rate was 0.46 clicks s - 1 (CV 0.05). PAM density estimates were in the range of 21.5 or 48.6 whales per 1000 km2 [CV 0.50 or 0.44, 95% confidence interval (CI) 20.7-22.4 or 47-50.9), depending on whether "uncertain" clicks were considered. Density estimates from concurrent sightings resulted in 33.7 whales per 1000 km2 (CV 0.77, 95% CI 8.9-50.5). Cue-count PAM methods under application provide reliable estimates of beaked whale density, over relatively long time periods and in realistic scenarios, as these match the concurrent density estimates obtained from visual observations.

AB0666 Body composition and physical function as potential prognostic biomarkers in patients with sIBM

Background

Sporadic inclusion body myositis (sIBM) is an acquired disease within the idiopathic inflammatory myopathy (IIM) spectrum, characterized clinically by progressive muscle atrophy, weakness and often severely impaired physical function leading to Sarcopenia. Despite of this, muscle mass and physical function is not routinely assessed in patients with sIBM.

Objectives

To investigate muscle mass, muscle power and physical function in patients with sIBM compared to healthy controls.

Methods

The study was a retrospective analysis of patients with sIBM (sIBM) and healthy age and gender matched controls (CON) from The Copenhagen Sarcopenia Study1. Appendicular lean mass (ALM) and skeletal muscle index (ALM/h2) was assessed by DXA (iDXA, GE). Muscle strength and physical function was evaluated by maximal horizontal gait speed (GS), 30-s sit-to-stand test (30s STS) and maximal leg extensor power (LEP) (PowerRig). A linear mixed-effect model for all outcome variables was used for the statistical analysis. A linear mixed-effect model for all outcome variables was used for the statistical analysis, including sex and health condition as fixed factors, and performed using SPSS v20 (Inc., Chicago, Illinois, USA), and the level of significance was set at α = 0.05 using two-tailed testing.

Results

In total, 22 patients with sIBM (18 men, age 69.8±4.6; 4 women, age 65.0±8.4) and 414 healthy age-matched controls (237 men, age 70.2±4.9; 177 women, age 65.5±5.4) were included. In men, ALM (sIBM: 21.4±3.1; CON: 25.3±3.6) and ALM/h2 (sIBM: 6.9±0.9; CON: 8.0±1.0) was reduced in sIBM compared to CON (p< 0.05), while there was no differences in ALM (sIBM: 17.4±1.4; CON: 18.0±2.5) and ALM/h2 (sIBM: 6.8±0.4; CON: 6.6±0.9) in women with sIBM compared to CON. In men, GS (sIBM: 1.05±0.23; CON: 2.20±0.50), 30s STS (sIBM: 6.1±3.8; CON: 17.8± 5.9) and LEP (sIBM: 79.4±57.3; CON: 255.8±81.3) was reduced in sIBM compared CON, respectively (p< 0.05). Likewise in women, GS (sIBM: 1.27±0.42; CON: 2.16±0.51), 30s STS (sIBM: 7.0±4.8; CON: 18.5±5.9) and LEP (sIBM: 76.5±23.4; CON: 163.7±51.6) was reduced compared CON, respectively (p< 0.05).

Conclusion

The present data demonstrate that muscle mass and physical function are reduced in patients with sIBM compared to healthy counterparts. Although data from larger studies are warranted, it may indicate that assessment body composition and physical function can be used as prognostic tools in these patients.

References

[1]Suetta et al, J Cachexia Sarcopenia Muscle 10(6):1316-1329, 2019

Disclosure of Interests

Kasper Yde Jensen: None declared, Julian Alcazar: None declared, Anders Nørkær Jørgensen Employee of: Currently employed at Ascendis Pharma, which do not produce drugs/devices used in rheumatology, Per Aagaard: None declared, Charlotte Suetta: None declared, Louise Pyndt Diederichsen: None declared

Optimized cultural conditions of functional yogurt for γ-aminobutyric acid augmentation using response surface methodology

Yogurt, a functional dairy food product, is an effective medium for delivering beneficial functional ingredients. One ingredient, γ-aminobutyric acid (GABA), has growing appeal in the development of functional foods for its potential in reducing the risk of diabetes, hypertension, and stress as a bioactive agent. However, the concentration of GABA in existing food products is remarkably low. We developed a functional yogurt rich in GABA using Streptococcus thermophilus fmb5. The GABA yield of yogurt was enhanced by optimization of culture conditions using single factor and response surface methods. The results showed that culture temperature, monosodium glutamate concentration, and culture time are the 3 main factors that affect GABA yield. The optimal culture conditions were determined as follows: 38.8°C for culture temperature, 20 g/L of monosodium glutamate, and 120 h of culture time. Under the above optimal conditions, the actual yield of GABA production was maximized at 9.66 g/L, which was 1.2 times or higher than that of from any single factor treatment. The GABA concentration, viable bacteria number, and water-holding capacity of GABA-rich yogurt were stable throughout the whole storage time. The results show that producing yogurt with Streptococcus thermophilus fmb5 and the optimized culture conditions will achieve high GABA concentrations that maximize health benefits to consumers.

Preclinical evaluation of [(18)F]JNJ42259152 as a PET tracer for PDE10A

Phosphodiesterase-10A (PDE10A) is implicated in several neuropsychiatric disorders involving basal ganglia neurotransmission, such as schizophrenia, obsessive-compulsive disorder and Huntington's disease. To confirm target engagement and exposure-occupancy relationships of clinical candidates for treatment, and to further explore the in vivo biology of PDE10A, non-invasive imaging using a specific PET ligand is warranted. Recently we have reported the in vivo evaluation of [(18)F]JNJ41510417 which showed specific binding to PDE10A in rat striatum, but with relatively slow kinetics. A chemically related derivative JNJ42259152 was found to have a similar in vivo occupancy, but lower lipophilicity and lower PDE10A in vitro inhibitory activity compared to JNJ41510417. (18)F-labeled JNJ42259152 was therefore evaluated as a potential PDE10A PET radiotracer. Baseline PET in rats and monkey showed specific retention in the PDE10A-rich striatum, and fast wash-out, with a good contrast to non-specific binding, in other brain regions. Pretreatment and chase experiments in rats with the selective PDE10A inhibitor MP-10 showed that tracer binding was specific and reversible. Absence of specific binding in PDE10A knock-out (KO) mice further confirmed PDE10A specificity. In vivo radiometabolite analysis using high performance liquid chromatography (HPLC) showed presence of polar radiometabolites in rat plasma and brain. In vivo imaging in rat and monkey further showed faster brain kinetics, and higher striatum-to-cerebellum ratios for [(18)F]JNJ42259152 compared to [(18)F]JNJ41510417. The arterial input function corrected for radiometabolites was determined in rats and basic kinetic modeling was established. For a 60-min acquisition time interval, striatal binding potential of the intact tracer referenced to the cerebellum showed good correlation with corresponding binding potential values of a Simplified Reference Tissue Model and referenced Logan Plot, the latter using a population averaged reference tissue-to-plasma clearance rate and offering the possibility to generate representative parametric binding potential images. In conclusion we can state that in vivo imaging in PDE10A KO mice, rats and monkey demonstrates that [(18)F]JNJ42259152 provides a PDE10A-specific signal in the striatum with good pharmacokinetic properties. Although presence of a polar radiometabolite in rat brain yielded a systematic but reproducible underestimation of the striatal BPND, a Logan reference tissue model approach using 60 min acquisition data is appropriate for quantification.

The role of urinary PGE2 and renin-angiotensin-aldosterone system in the pathogenesis of essential hypertension

In a group of 26 patients diagnosed as essential hypertensive (EH) and in a control group (CG) of 27 normotensive volunteers the urinary excretion of PGE2, plasma renin activity (PRA) and plasma aldosterone were measured. EH patients were classified into normoreninemic (NREH) (n = 21) and hyporeninemic (LREH) (n = 5) by the response of PRA to the combined stimuli of ambulation and furosemide. Urinary PGE2 excretion was higher in NREH than in CG (p less than 0.05) while LREH showed values lower than in CG (p less than 0.001). Plasma aldosterone levels were similar in the three groups. In CG and EH patients PRA and urinary PGE2 were closely related (CG r = 0.516, p less than 0.05, EH patients r = 0.674, p less than 0.001). Indomethacin administration induced a decrease of PGE2 in both CG (n = 8) and NREH (n = 8) (p less than 0.01). In contrast, indomethacin induced no changes in PGE2 excretion of LREH (n = 5). Furthermore in the group of patients with NREH indomethacin induced a significant increase in blood pressure (p less than 0.01) and body weight (p less than 0.01) while glomerular filtration rate, 24 hour natriuresis PRA and plasma aldosterone decreased (p less than 0.01). On the contrary, in LREH indomethacin did not alter any of the parameters measured. These results indicate that LREH and NREH may be regarded as two different populations distinguishable not only by different secretion of PRA but also by different excretion of PGE2 in urine and by their characteristic response to indomethacin.

Role of renal prostaglandin E2 in chronic renal disease hypertension

The role played by renal prostaglandin E2 in the maintenance of hypertension in chronic renal disease has been investigated through studying the response of body weight, blood pressure, glomerular filtration rate (GFR), 24-hour natriuresis, plasma renin activity (PRA), plasma aldosterone and urinary PGE2 excretion to the administration of indomethacin (2mg/kg daily, during 3 days). A group of 37 patients diagnosed as having chronic renal parenchymatous disease with creatinine clearance above 25 ml/min was included in the study. 21 of them were hypertensive (BP greater than 160/95). 27 normotensive volunteers were also studied and considered as the control group. The initial study disclosed similar levels of PGE2, PRA and plasma aldosterone in volunteers, normotensive patients and hypertensive patients, although the sodium intake was lower in the last two groups. A positive correlation between PRA and urinary PGE2 was found both in normotensive (r = 0.507, p less than 0.01) and in hypertensive patients (r = 0.609, p less than 0.01). The administration of indomethacin induced a diminution of PRA, plasma aldosterone and urinary PGE2 levels together with an increase in diastolic blood pressure (p less than 0.05-0.01) in both volunteers and patients. The remaining parameters measured did not change in volunteers or in normotensive patients. On the contrary, in hypertensive patients, during indomethacin administration, lower values of creatinine clearance (p less than 0.005) and 24-hour natriuresis (p less than 0.05) together with an increase in body weight (p less than 0.01) were observed. These results point to the existence of a protective role of renal prostaglandin E2 upon renal function when hypertension appears in the course of chronic renal parenchymatous disease.