Probing many-body dynamics in a two-dimensional dipolar spin ensemble

The most direct approach for characterizing the quantum dynamics of a strongly interacting system is to measure the time evolution of its full many-body state. Despite the conceptual simplicity of this approach, it quickly becomes intractable as the system size grows. An alternate approach is to think of the many-body dynamics as generating noise, which can be measured by the decoherence of a probe qubit. Here we investigate what the decoherence dynamics of such a probe tells us about the many-body system. In particular, we utilize optically addressable probe spins to experimentally characterize both static and dynamical properties of strongly interacting magnetic dipoles. Our experimental platform consists of two types of spin defects in nitrogen delta-doped diamond: nitrogen-vacancy colour centres, which we use as probe spins, and a many-body ensemble of substitutional nitrogen impurities. We demonstrate that the many-body system's dimensionality, dynamics and disorder are naturally encoded in the probe spins' decoherence profile. Furthermore, we obtain direct control over the spectral properties of the many-body system, with potential applications in quantum sensing and simulation.

Many-body-localized discrete time crystal with a programmable spin-based quantum simulator

[Figure: see text].

Autonomic and cardiac evaluation upon sub-therapeutic doxorubicin administration

 

Doxorubicin (DOX) is a chemotherapeutic agent that improves the survival and quality of life of patients with solid tumours. However, these improvements are counterbalanced by various dose-dependent side effects including cardiac dysfunction, which may occur in a subset of patients leading to treatment discontinuation. In addition, despite overall insufficiently studied, available data clearly show that women are more susceptible to drugs toxicity due to sex differences in drug metabolism or sensitivity. Regarding doxorubicin, apart its acute toxicity, women are also more vulnerable to late cardiotoxicity. Currently, there are no robust clinical imaging techniques or biomarkers available to detect DOX-cardiotoxicity before functional decline and, despite treatment personalization, subclinical signs of toxicity are not yet well identified.

Thus, in the present work, we sought to characterize the toxic effects of a sub-therapeutic dose of doxorubicin upon cardiovascular and autonomic function. For that, adult healthy female wistar rats (n=14), aged >3 months, were intraperitoneally treated with doxorubicin (2 mg/kg) at weekly intervals for up to 4 weeks. A control (Ctrl, n=7) group received saline solution 0,9% NaCl as a vehicle. Rats underwent an echocardiographic evaluation at 4 weeks. Blood pressure, heart rate and respiratory frequency were assessed in an acute experiment. Cardiovascular variability studies in the time-frequency domain (LF, HF and LF/HF calculation) and cardiorespiratory reflexes assessment were performed. T-Student test for paired observations was applied (level significance p<0.05)

DOX-treated animals showed a severe bradypnea and hypotension, significant decrease in ejection fraction and fractional shortening, sympatho-inhibition and reduced baroreceptor reflex gain and chemoreflex sensitivity. Our functional results might be due to cellular respiratory dysfunction and vascular adaptations induced by doxorubicin via TNF alpha actions at central nervous system (CNS) and peripheral level.

In fact, peripheral TNF alpha release elicits NO production, which through vasodilation will induce hypotension and baroreceptor reflex adjustments. Reinforcing these actions, and despite doxorubicin low ability to pass BBB, TNF alpha acting at CNS induces neuronal apoptosis and impairment of mitochondrial function which might also contribute to affect autonomic and respiratory function, expressed by a decreased chemoreflex sensitivity and sympathetic tone.

In conclusion, sub-therapeutic doses of doxorubicin are able to produce per se the impairment of autonomic and cardiac functions. Thus, a tight monitoring of these functions in patients treated with therapeutic doses of doxorubicin is highly recommended.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Fundação para a Ciência e a Tecnologia

Observation of a prethermal discrete time crystal

Extending the framework of statistical physics to the nonequilibrium setting has led to the discovery of previously unidentified phases of matter, often catalyzed by periodic driving. However, preventing the runaway heating that is associated with driving a strongly interacting quantum system remains a challenge in the investigation of these newly discovered phases. In this work, we utilize a trapped-ion quantum simulator to observe the signatures of a nonequilibrium driven phase without disorder-the prethermal discrete time crystal. Here, the heating problem is circumvented not by disorder-induced many-body localization, but rather by high-frequency driving, which leads to an expansive time window where nonequilibrium phases can emerge. Floquet prethermalization is thus presented as a general strategy for creating, stabilizing, and studying intrinsically out-of-equilibrium phases of matter.

Imaging stress and magnetism at high pressures using a nanoscale quantum sensor

Pressure alters the physical, chemical, and electronic properties of matter. The diamond anvil cell enables tabletop experiments to investigate a diverse landscape of high-pressure phenomena. Here, we introduce and use a nanoscale sensing platform that integrates nitrogen-vacancy (NV) color centers directly into the culet of diamond anvils. We demonstrate the versatility of this platform by performing diffraction-limited imaging of both stress fields and magnetism as a function of pressure and temperature. We quantify all normal and shear stress components and demonstrate vector magnetic field imaging, enabling measurement of the pressure-driven α↔ϵ phase transition in iron and the complex pressure-temperature phase diagram of gadolinium. A complementary NV-sensing modality using noise spectroscopy enables the characterization of phase transitions even in the absence of static magnetic signatures.

Imaging the Local Charge Environment of Nitrogen-Vacancy Centers in Diamond

Characterizing the local internal environment surrounding solid-state spin defects is crucial to harnessing them as nanoscale sensors of external fields. This is especially germane to the case of defect ensembles which can exhibit a complex interplay between interactions, internal fields, and lattice strain. Working with the nitrogen-vacancy (NV) center in diamond, we demonstrate that local electric fields dominate the magnetic resonance behavior of NV ensembles at a low magnetic field. We introduce a simple microscopic model that quantitatively captures the observed spectra for samples with NV concentrations spanning more than two orders of magnitude. Motivated by this understanding, we propose and implement a novel method for the nanoscale localization of individual charges within the diamond lattice; our approach relies upon the fact that the charge induces a NV dark state which depends on the electric field orientation.

The influence of the morphological characteristics of nanoporous anodic aluminium oxide (AAO) structures on capacitive touch sensor performance: a biological application

This work is devoted to the study of the influence of different anodic aluminium oxide (AAO) morphologies on the sensitivity and performance of an AAO-based capacitive touch sensor. The AAO structures were fabricated in a cylindrical homemade anodization cell made from a solid polycarbonate billet via a lathe machining process. The AAO morphologies were obtained from the anodization of Al foil by using three different types of electrolyte (sulphuric acid, oxalic acid and phosphoric acid) and their morphologies are reported and compared using scanning electron microscopy (SEM) micrographs and current–time characteristic curves. The sensors were fabricated by integrating the AAO structure with a nanotextured gold thin film deposited over the AAO layer by thermal evaporation, thus realizing a type of metal/insulator/metal parallel-plate capacitance sensor. It is demonstrated that AAO morphologies have influence on the performance of the AAO-based capacitive touch sensors. The variation of the capacitance of the sensors is investigated in this work for the AAO structures produced from anodization in an attempt to select anodizing conditions for a biological application aiming to detect small microorganisms such as bacterial colonies of Escherichia coli.

This work is devoted to the study of the influence of different anodic aluminium oxide (AAO) morphologies on the sensitivity and performance of an AAO-based capacitive touch sensor.

Position Paper from the Portuguese Association of Hospital Pharmacists for biosimilar therapeutic antibodies

WHAT IS KNOWN AND OBJECTIVE

Biopharmaceuticals are an important class of drugs for the treatment of autoimmune/inflammatory and oncologic diseases. With patent expiries, biotechnological manufacturers can now develop biosimilar drugs. Due to timeliness of introducing new and more complex biosimilars, the Portuguese Association of Hospital Pharmacists gathered to develop a common positioning on the use of biosimilar monoclonal antibodies.

MAIN ISSUES

The European pathway to biosimilar approval was developed to improve affordability and access to biological therapies, but it remains a work in progress because unresolved issues remain. Due to the present reality of biosimilar monoclonal antibodies, hospital pharmacists must play an important role in ensuring the safe, effective and cost-effective use of biosimilars in health systems; and educating healthcare administrators, providers, legislators, policymakers, payors and patients about these products.

WHAT IS NEW AND CONCLUSION

The conclusions presented in this work focused on the proposal for optimal biosimilar prescription criteria, the preparation of original biologics and biosimilars in the pharmacy, the management and selection of suppliers, extrapolation issues, the specific role of pharmacovigilance and risk management for the optimal use of biosimilar monoclonal antibodies.

Evaluation of Toll-like, chemokine, and integrin receptors on monocytes and neutrophils from peripheral blood of septic patients and their correlation with clinical outcomes

Recognition of pathogens is performed by specific receptors in cells of the innate immune system, which may undergo modulation during the continuum of clinical manifestations of sepsis. Monocytes and neutrophils play a key role in host defense by sensing and destroying microorganisms. This study aimed to evaluate the expression of CD14 receptors on monocytes; CD66b and CXCR2 receptors on neutrophils; and TLR2, TLR4, TLR5, TLR9, and CD11b receptors on both cell types of septic patients. Seventy-seven septic patients (SP) and 40 healthy volunteers (HV) were included in the study, and blood samples were collected on day zero (D0) and after 7 days of therapy (D7). Evaluation of the cellular receptors was carried out by flow cytometry. Expression of CD14 on monocytes and of CD11b and CXCR2 on neutrophils from SP was lower than that from HV. Conversely, expression of TLR5 on monocytes and neutrophils was higher in SP compared with HV. Expression of TLR2 on the surface of neutrophils and that of TLR5 on monocytes and neutrophils of SP was lower at D7 than at D0. In addition, SP who survived showed reduced expression of TLR2 and TLR4 on the surface of neutrophils at D7 compared to D0. Expression of CXCR2 for surviving patients was higher at follow-up compared to baseline. We conclude that expression of recognition and cell signaling receptors is differentially regulated between SP and HV depending on the receptor being evaluated.

Predictive value of pulse pressure variation for fluid responsiveness in septic patients using lung-protective ventilation strategies

Background

The applicability of pulse pressure variation (ΔPP) to predict fluid responsiveness using lung-protective ventilation strategies is uncertain in clinical practice. We designed this study to evaluate the accuracy of this parameter in predicting the fluid responsiveness of septic patients ventilated with low tidal volumes (TV) (6 ml kg⁻¹).

Methods

Forty patients after the resuscitation phase of severe sepsis and septic shock who were mechanically ventilated with 6 ml kg⁻¹ were included. The ΔPP was obtained automatically at baseline and after a standardized fluid challenge (7 ml kg⁻¹). Patients whose cardiac output increased by more than 15% were considered fluid responders. The predictive values of ΔPP and static variables [right atrial pressure (RAP) and pulmonary artery occlusion pressure (PAOP)] were evaluated through a receiver operating characteristic (ROC) curve analysis.

Results

Thirty-four patients had characteristics consistent with acute lung injury or acute respiratory distress syndrome and were ventilated with high levels of PEEP [median (inter-quartile range) 10.0 (10.0–13.5)]. Nineteen patients were considered fluid responders. The RAP and PAOP significantly increased, and ΔPP significantly decreased after volume expansion. The ΔPP performance [ROC curve area: 0.91 (0.82–1.0)] was better than that of the RAP [ROC curve area: 0.73 (0.59–0.90)] and pulmonary artery occlusion pressure [ROC curve area: 0.58 (0.40–0.76)]. The ROC curve analysis revealed that the best cut-off for ΔPP was 6.5%, with a sensitivity of 0.89, specificity of 0.90, positive predictive value of 0.89, and negative predictive value of 0.90.

Conclusions

Automatized ΔPP accurately predicted fluid responsiveness in septic patients ventilated with low TV.

A reconfigurable, wearable, wireless ECG system

New emerging concepts as "wireless hospital", "mobile healthcare" or "wearable telemonitoring" require the development of bio-signal acquisition devices to be easily integrated into the clinical routine. In this work, we present a new system for Electrocardiogram (ECG) acquisition and its processing, with wireless transmission on demand (either the complete ECG or only one alarm message, just in case a pathological heart rate detected). Size and power consumption are optimized in order to provide mobility and comfort to the patient. We have designed a modular hardware system and an autonomous platform based on a Field-Programmable Gate Array (FPGA) for developing and debugging. The modular approach allows to redesign the system in an easy way. Its adaptation to a new biomedical signal would only need small changes on it. The hardware system is composed of three layers that can be plugged/unplugged: communication layer, processing layer and sensor layer. In addition, we also present a general purpose end-user application developed for mobile phones or Personal Digital Assistant devices (PDAs).