Task-adaptive physical reservoir computing.

Reservoir computing is a neuromorphic architecture that may offer viable solutions to the growing energy costs of machine learning. In software-based machine learning, computing performance can be readily reconfigured to suit different computational tasks by tuning hyperparameters. This critical functionality is missing in 'physical' reservoir computing schemes that exploit nonlinear and history-dependent responses of physical systems for data processing. Here we overcome this issue with a 'task-adaptive' approach to physical reservoir computing. By leveraging a thermodynamical phase space to reconfigure key reservoir properties, we optimize computational performance across a diverse task set. We use the spin-wave spectra of the chiral magnet Cu2OSeO3 that hosts skyrmion, conical and helical magnetic phases, providing on-demand access to different computational reservoir responses. The task-adaptive approach is applicable to a wide variety of physical systems, which we show in other chiral magnets via above (and near) room-temperature demonstrations in Co8.5Zn8.5Mn3 (and FeGe).

The Stress of Measuring Plantar Tissue Stress in People with Diabetes-Related Foot Ulcers: Biomechanical and Feasibility Findings from Two Prospective Cohort Studies.

Reducing high mechanical stress is imperative to heal diabetes-related foot ulcers. We explored the association of cumulative plantar tissue stress (CPTS) and plantar foot ulcer healing, and the feasibility of measuring CPTS, in two prospective cohort studies (Australia (AU) and The Netherlands (NL)). Both studies used multiple sensors to measure factors to determine CPTS: plantar pressures, weight-bearing activities, and adherence to offloading treatments, with thermal stress response also measured to estimate shear stress in the AU-study. The primary outcome was ulcer healing at 12 weeks. Twenty-five participants were recruited: 13 in the AU-study and 12 in the NL-study. CPTS data were complete for five participants (38%) at baseline and one (8%) during follow-up in the AU-study, and one (8%) at baseline and zero (0%) during follow-up in the NL-study. Reasons for low completion at baseline were technical issues (AU-study: 31%, NL-study: 50%), non-adherent participants (15% and 8%) or combinations (15% and 33%); and at follow-up refusal of participants (62% and 25%). These underpowered findings showed that CPTS was non-significantly lower in people who healed compared with non-healed people (457 [117; 727], 679 [312; 1327] MPa·s/day). Current feasibility of CPTS seems low, given technical challenges and non-adherence, which may reflect the burden of treating diabetes-related foot ulcers.

Five Specific Tongue Movements in a Healthy Population.

The importance of tongue mobility on speech, oral food transport, and swallowing is well recognized. However, whether the individual tongue mobility influences postoperative function in oral cancer treatment remains to be elucidated. This study assesses the ability to perform five tongue movements as rolling, twisting (two sides), folding, and the 'cloverleaf' in a healthy population. Because a tumor in oral cancer patients often restricts the mobility of the tongue, it might be helpful to know if it is possible to recall any of those movements without demonstrating it. Two observers asked 387 Dutch healthy adults if they could perform one of the five specific tongue movements and were subsequently asked to demonstrate the five movements. The distribution in the Dutch population is: rolling: 83.7%, cloverleaf: 14.7%, folding: 27.5%, twisting left: 36.1% and twisting right: 35.6%. The percentage of people that can fold their tongue is almost ten times higher (3% versus 27.5%) than in previous research, and it was found that the ability to roll the tongue is not a prerequisite for folding of the tongue. A relationship between gender or right-handedness and the ability to perform certain tongue movements could not be found. Of the participants, 9.9% and 13.1% incorrectly assumed that they could demonstrate tongue rolling and cloverleaf. Tongue folding and twisting (left or right) were incorrectly assumed in 36.9%, 24.1%, and 25.4% of the cases. Rolling and cloverleaf are preferred for future prediction models because these movements are easy to recall without demonstrating.

Exploratory data analysis of the dependencies between skin permeability, molecular weight and log P.

Molecular weight and log P remain the most frequently used physicochemical properties in models that predict skin permeability. However, several reports over the past two decades have suggested that predictions made by these models may not be sufficiently accurate. In this study, exploratory data analysis of the probabilistic dependencies between molecular weight, log P and log Kp was performed on a dataset constructed from the combination of several popular datasets. The results suggest that, in general, molecular weight and log P are poorly correlated to log Kp. However, after employing several exploratory data analysis techniques, regions within the dataset of statistically significant dependence were identified. As an example of the applicability of the information extracted from the exploratory data analyses, a multiple linear regression model was constructed, bounded by the ranges of dependence. This model gave reasonable approximations to log Kp values obtained from skin permeability studies of selected non-steroidal ant-inflammatory drugs (NSAIDs) administered from a buffer solution and a lipid-based drug delivery system. A method of testing whether a given drug falls within the regions of statistical dependence was also presented. Knowing the ranges within which molecular weight and log P are statistically related to log Kp can supplement existing methods of screening, risk analysis or early drug development decision making to add confidence to predictions made regarding skin permeability.

Neuromorphic overparameterisation and few-shot learning in multilayer physical neural networks.

Physical neuromorphic computing, exploiting the complex dynamics of physical systems, has seen rapid advancements in sophistication and performance. Physical reservoir computing, a subset of neuromorphic computing, faces limitations due to its reliance on single systems. This constrains output dimensionality and dynamic range, limiting performance to a narrow range of tasks. Here, we engineer a suite of nanomagnetic array physical reservoirs and interconnect them in parallel and series to create a multilayer neural network architecture. The output of one reservoir is recorded, scaled and virtually fed as input to the next reservoir. This networked approach increases output dimensionality, internal dynamics and computational performance. We demonstrate that a physical neuromorphic system can achieve an overparameterised state, facilitating meta-learning on small training sets and yielding strong performance across a wide range of tasks. Our approach's efficacy is further demonstrated through few-shot learning, where the system rapidly adapts to new tasks.

Ultrastrong magnon-magnon coupling and chiral spin-texture control in a dipolar 3D multilayered artificial spin-vortex ice.

Strongly-interacting nanomagnetic arrays are ideal systems for exploring reconfigurable magnonics. They provide huge microstate spaces and integrated solutions for storage and neuromorphic computing alongside GHz functionality. These systems may be broadly assessed by their range of reliably accessible states and the strength of magnon coupling phenomena and nonlinearities. Increasingly, nanomagnetic systems are expanding into three-dimensional architectures. This has enhanced the range of available magnetic microstates and functional behaviours, but engineering control over 3D states and dynamics remains challenging. Here, we introduce a 3D magnonic metamaterial composed from multilayered artificial spin ice nanoarrays. Comprising two magnetic layers separated by a non-magnetic spacer, each nanoisland may assume four macrospin or vortex states per magnetic layer. This creates a system with a rich 16N microstate space and intense static and dynamic dipolar magnetic coupling. The system exhibits a broad range of emergent phenomena driven by the strong inter-layer dipolar interaction, including ultrastrong magnon-magnon coupling with normalised coupling rates of Δ f ν = 0.57 , GHz mode shifts in zero applied field and chirality-control of magnetic vortex microstates with corresponding magnonic spectra.

Reconfigurable training and reservoir computing in an artificial spin-vortex ice via spin-wave fingerprinting.

Strongly interacting artificial spin systems are moving beyond mimicking naturally occurring materials to emerge as versatile functional platforms, from reconfigurable magnonics to neuromorphic computing. Typically, artificial spin systems comprise nanomagnets with a single magnetization texture: collinear macrospins or chiral vortices. By tuning nanoarray dimensions we have achieved macrospin-vortex bistability and demonstrated a four-state metamaterial spin system, the 'artificial spin-vortex ice' (ASVI). ASVI can host Ising-like macrospins with strong ice-like vertex interactions and weakly coupled vortices with low stray dipolar field. Vortices and macrospins exhibit starkly differing spin-wave spectra with analogue mode amplitude control and mode frequency shifts of Δf = 3.8 GHz. The enhanced bitextural microstate space gives rise to emergent physical memory phenomena, with ratchet-like vortex injection and history-dependent non-linear fading memory when driven through global magnetic field cycles. We employed spin-wave microstate fingerprinting for rapid, scalable readout of vortex and macrospin populations, and leveraged this for spin-wave reservoir computation. ASVI performs non-linear mapping transformations of diverse input and target signals in addition to chaotic time-series forecasting.

Reconfigurable magnonic mode-hybridisation and spectral control in a bicomponent artificial spin ice.

Strongly-interacting nanomagnetic arrays are finding increasing use as model host systems for reconfigurable magnonics. The strong inter-element coupling allows for stark spectral differences across a broad microstate space due to shifts in the dipolar field landscape. While these systems have yielded impressive initial results, developing rapid, scaleable means to access a broad range of spectrally-distinct microstates is an open research problem. We present a scheme whereby square artificial spin ice is modified by widening a 'staircase' subset of bars relative to the rest of the array, allowing preparation of any ordered vertex state via simple global-field protocols. Available microstates range from the system ground-state to high-energy 'monopole' states, with rich and distinct microstate-specific magnon spectra observed. Microstate-dependent mode-hybridisation and anticrossings are observed at both remanence and in-field with dynamic coupling strength tunable via microstate-selection. Experimental coupling strengths are found up to g/2π = 0.16 GHz. Microstate control allows fine mode-frequency shifting, gap creation and closing, and active mode number selection.

Comparison of Spin-Wave Modes in Connected and Disconnected Artificial Spin Ice Nanostructures Using Brillouin Light Scattering Spectroscopy.

Artificial spin ice systems have seen burgeoning interest due to their intriguing physics and potential applications in reprogrammable memory, logic, and magnonics. Integration of artificial spin ice with functional magnonics is a relatively recent research direction, with a host of promising results. As the field progresses, direct in-depth comparisons of distinct artificial spin systems are crucial to advancing the field. While studies have investigated the effects of different lattice geometries, little comparison exists between systems comprising continuously connected nanostructures, where spin-waves propagate via dipole-exchange interaction, and systems with nanobars disconnected at vertices, where spin-wave propagation occurs via stray dipolar field. Gaining understanding of how these very different coupling methods affect both spin-wave dynamics and magnetic reversal is key for the field to progress and provides crucial system-design information including for future systems containing combinations of connected and disconnected elements. Here, we study the magnonic response of two kagome spin ices via Brillouin light scattering, a continuously connected system and a disconnected system with vertex gaps. We observe distinct high-frequency dynamics and magnetization reversal regimes between the systems, with key distinctions in spin-wave localization and mode quantization, microstate trajectory during reversal and internal field profiles. These observations are pertinent for the fundamental understanding of artificial spin systems and broader design and engineering of reconfigurable functional magnonic crystals.

Magnonic Bending, Phase Shifting and Interferometry in a 2D Reconfigurable Nanodisk Crystal.

Strongly interacting nanomagnetic systems are pivotal across next-generation technologies including reconfigurable magnonics and neuromorphic computation. Controlling magnetization states and local coupling between neighboring nanoelements allows vast reconfigurability and a host of associated functionalities. However, existing designs typically suffer from an inability to tailor interelement coupling post-fabrication and nanoelements restricted to a pair of Ising-like magnetization states. Here, we propose a class of reconfigurable magnonic crystals incorporating nanodisks as the functional element. Ferromagnetic nanodisks are crucially bistable in macrospin and vortex states, allowing interelement coupling to be selectively activated (macrospin) or deactivated (vortex). Through microstate engineering, we leverage the distinct coupling behaviors and magnonic band structures of bistable nanodisks to achieve reprogrammable magnonic waveguiding, bending, gating, and phase-shifting across a 2D network. The potential of nanodisk-based magnonics for wave-based computation is demonstrated via an all-magnon interferometer exhibiting XNOR logic functionality. Local microstate control is achieved here via topological magnetic writing using a magnetic force microscope tip.

Methylcellulose - a versatile printing material that enables biofabrication of tissue equivalents with high shape fidelity.

With the aid of biofabrication, cells can be spatially arranged in three dimensions, which offers the opportunity to guide tissue maturation in a better way compared to traditional tissue engineering approaches. A prominent technique allowing biofabrication of tissue equivalents is extrusion-based 3D (bio)printing, also called 3D (bio)plotting or robocasting, which comprises cells embedded in the biomaterial (bioink) during the fabrication process. First bioprinting studies introduced bioinks allowing either good cell viability or good shape fidelity. Concepts enabling printing of cell-laden constructs with high shape fidelity were developed only rarely. Recent studies showed the great potential of the polysaccharide methylcellulose (mc) as supportive biomaterial that can be utilized in various ways to enable biofabrication and especially extrusion-based bioprinting of bioinks. This minireview highlights the multiple applications of mc for biofabrication: it was successfully used as sacrificial ink to enable 3D shaping of cell sheets or biomaterial inks as well as as internal stabilizing component of various bioinks. Moreover, a brief overview about first bioprinted functional tissue equivalents is given, which have been fabricated by using mc. Based on these studies, future research should consider mc as an auxiliary material for bioinks and biofabricated constructs with high shape fidelity.

Development of a clay based bioink for 3D cell printing for skeletal application.

Three-dimensional printing of cell-laden hydrogels has evolved as a promising approach on the route to patient-specific or complex tissue-engineered constructs. However, it is still challenging to print structures with both, high shape fidelity and cell vitality. Herein, we used a synthetic nanosilicate clay, called Laponite, to build up scaffolds utilising the extrusion-based method 3D plotting. By blending with alginate and methylcellulose, a bioink was developed which allowed easy extrusion, achieving scaffolds with high printing fidelity. Following extrusion, approximately 70%-75% of printed immortalised human mesenchymal stem cells survived and cell viability was maintained over 21 days within the plotted constructs. Mechanical properties of scaffolds comprised of the composite bioink decreased over time when stored under cell culture conditions. Nevertheless, shape of the plotted constructs was preserved even over longer cultivation periods. Laponite is known for its favourable drug delivery properties. Two model proteins, bovine serum albumin and vascular endothelial growth factor were loaded into the bioink. We demonstrate that the release of both growth factors significantly changed to a more sustained profile by inclusion of Laponite in comparison to an alginate-methylcellulose blend in the absence of Laponite. In summary, addition of a synthetic clay, Laponite, improved printability, increased shape fidelity and was beneficial for controlled release of biologically active agents such as growth factors.

Detection of anisotropic hyperfine transitions in zero magnetic field using field-cycling techniques.

For the first time, we describe the detection of hyperfine transitions in zero magnetic field using field-cycling techniques and pulsed EPR spectroscopy. The sample investigated was coal, which shows an anisotropic electron spin-(13)C hyperfine interaction.

The influence of multiple scorers on cytogenetics study results.

Cytogenetics data resulting from one laboratory in a multiple-laboratory study were analyzed to determine if 5 well-trained scorers produced significantly different results using metaphase scoring procedures. Although the scorers reached the same general conclusion, results show that scorer differences exists (p less than 0.01). Consequently, all participating scorers in a laboratory should be used equally in all treatment groups and the results should be analyzed accordingly to account for scorer variations. This is easily accomplished in controlled prospective experiments; however, it is often difficult in retrospective studies using data which exists. In such studies, every effort should be made to analyze and interpret the data so that scorer differences are taken into account. For severely damaged cells not only were there scorer differences but the difference were greater at higher doses. This phenomenon may be related to the operational definition of a severely damaged cell, since scorers who identify more damage than other scorers would logically tend to classify more cells as severely damaged both overall and at lower doses.

The impact of severely damaged cells in cytogenetic research.

In a large multilaboratory cytogenetic study of interlaboratory variations using 4 dose levels of triethylenemelamine and a control, a severely damaged cell was operationally defined as a cell which contained at least 10 aberrations of any type. A review of this study suggested that the use of this definition introduced a bias in the measurement and interpretation of results for the other cytogenetic categories studied. As a result, the original severely damaged cells were carefully reanalyzed to investigate the characteristics of this bias and to seek procedures to minimize or eliminate it. Results characterize this bias and demonstrate that when a severely damaged cell is defined as one containing at least 20 aberrations and those aberrations in the remaining non-severely damaged cells are classified by specific type, the bias is significantly reduced and chromosome analysis can be improved as a test system.

A collaborative cytogenetics study to measure and minimize interlaboratory variation.

Six cytogenetics laboratories joined in a collaborative study of rat chromosome aberrations to measure interlaboratory variation in results of standardized procedures and to devise methods to minimize interlaboratory differences. A preliminary workshop was held to resolve scoring differences, to develop a joint protocol and common glossary, and to reach agreement on uniform reporting methods. Osborne-Mendel rats from a common source were sent to each laboratory. Triethylenemelamine (TEM) was used at doses of 100, 200, 300 and 400 microgram/kg to induce clastogenic effects; results were compared to those of a control group of untreated animals. Femoral bone marrow cells were evaluated with the scorers unaware of the dosage. Final results showed highly significant dose effects with the test compound, and most laboratories showed a similar pattern of dose response. This study illustrates that rat cytogenetic analysis can be an effective test system for evaluation of a compound for mutagenic potential, particularly for the index reflecting the proportion of abnormal cells, but that results should be interpreted cautiously when arbitrary values are assigned for some of the categories being analyzed, as was done in this project for the category of severely damaged cells.

[Effect of fundus vagotomy on the gastric emptying of the solids and liquids of a meal in patients with and without postoperative duodenal ulcer recurrence]. / Effet de la vagotomie fundique sur la vidange gastrique des solides et des liquides d'un repas chez des patients avec et sans récidive ulcéreuse duodénale post-opératoire.

The effects of fundic vagotomy (FV) on gastric emptying in the solid and liquid phases of a meal were studied by an isotopic technique in 12 patients with duodenal ulcer. Postoperative results were compared with those obtained in the same subjects before FV and with control values obtained in an identical group of healthy subjects. Early gastric emptying (perprandial) of the two phases of the meal was enhanced by FV but the results failed to reach statistical significance. Gastric emptying of liquids, measured during the 3 h following the end of the meal, was not significantly modified by FV (half-emptying times: 62 +/- 5 min before FV, 75 +/- 8 min after and 65 +/- 7 min for controls). That of solids was significantly delayed by FV (per cent emptied by min: 0.50 +/- 0.02 p. 100 before FV, 0.40 +/- 0.03 p. 100 after, and 0.49 +/- 0.02 p. 100 for controls); this delay was found in all but one patient, but the difference was very slight. Eleven of the 12 investigated patients cured by the operation, were compared with 6 subjects presenting with post FV recurrence: gastric emptying rates of solids (0.41 +/- 0.02 p. 100/min and 0.47 +/- 0.07 p. 100/min) and half emptying times of liquids (72 +/- 10 min and 61 +/- 10 min) were not significantly different. Thus, the gastric emptying rate of an ordinary meal remains practically unchanged by FV and postoperative recurrences of duodenal ulcer cannot be explained by alteration of gastric evacuation.

[Endosonography in epithelial rectal tumors. Value of a differentiated therapy concept]. / Endosonographie bei epithelialen Rectumtumoren. Stellenwert in einem differenzierten Therapiekonzept.

INTRODUCTION: Endorectal ultrasound (EU) is the most important examination for pretherapeutic stratification of primary rectal tumors. Preoperative histology and endosonography determine the therapeutic strategy by using the criteria of depth of infiltration (uT) and lymph node status (uN). METHODS: The effectiveness of endoluminal ultrasound in the preoperative differentiation between locally restricted tumors (adenomas and "low-risk" carcinomas, uT0/1, G1-2) and advanced rectal carcinomas (uT3) was assessed in a retrospective study of 284 patients. In the examination period (UZ) from 3/94 to 12/97 (UZ I) 104 patients (group 1) were examined with a 7-MHz endoprobe, and from 1/98 to 12/99 (UZ II), 116 (group 2) with a 10-MHz endoprobe. Additionally, in 64 patients (group 3) with an advanced uT3/4 or uN + tumor we compared the accuracy of ultrasound with computed tomography (CT). In this group 32 patients were restaged by EU and CT after preoperative chemoradiation. The results of präoperative endorectal ultrasound were correlated with the postoperative histological data. RESULTS: Concerning the whole period (UZ I and II) we achieved a total hit rate of 83.6% for adenomas and "low-risk" carcinomas (uT0/1, G1/2) by EU (79.8% in UZ I, 87.1% in UZ II). For advanced rectal carcinoma (> or = uT3) we found a total accuracy of 87.3% (82.7% in UZ I, 91.4% in UZ II). In 62 cases endosonographic lymph node status was correlated with postoperative histology during UZ II, with a hit rate of 64.5%. In group 3 (n = 64), in 32 patients without preoperative chemoradiation we found an accuracy for depth infiltration of 93% (EU) and 82% (CT). Concerning lymph node status there was a correlation of 57% (EU) and 64% (CT). After preoperative chemoradiation (n = 32) we found an accuracy of 91% (EU) and 73% (CT) for depth infiltration--for lymph node status 70% (EU) and 82% (CT). CONCLUSIONS: High accuracy in endoluminal ultrasound leads to a secure and differentiated stratification of therapy in primary rectal tumors. The hit rate concerning depth of infiltration is higher for EU than for CT both before and after chemoradiation, but not regarding lymph node status.