Short Step Research Articles

Duloxetine-associated parkinsonism in a patient with subclinical parkinson's disease: a case report.

Duloxetine is a serotonin-norepinephrine reuptake inhibitor commonly used to treat depression and neuropathic pain. Duloxetine-associated parkinsonism has been previously reported in only two cases with psychiatric disorders. We present the first case where duloxetine unmasked motor manifestations of subclinical Parkinson's disease. A 41-year-old male underwent a discectomy for a lumbar herniation. As numbness in the left sole persisted postoperatively, duloxetine (20 mg/day) was initiated seven days after surgery. Two dayslater, the patient developed a slow gait, difficulty turning, and short steps. Neurological examination revealed resting tremor in the left foot, dystonic posturing of the left little toe, bradykinesia of both hands, reduced gait speed with short steps, and rigidity in the left lower limb and neck. Based on the temporal association, duloxetine-associated parkinsonism was suspected. Four days after discontinuing duloxetine, the patient's gait speed, step length, and right-hand bradykinesia improved, and the foot tremor and toe dystonia resolved. Dopamine transporter single-photon emission computed tomography revealed reduced tracer uptake in the bilateral striatum, leading to a diagnosis of duloxetine-associated parkinsonism and subclinical Parkinson's disease. One year and four months later, gait impairment reappeared, characterized by short steps and slow speed, though without foot tremor or toe dystonia. In this case, duloxetine appeared to unmask parkinsonism associated with subclinical Parkinson's disease. Potential mechanisms include inhibition of dopamine release due to 5-HT2 receptor activation, postoperative effects, drug hypersensitivity, or genetic phenotypes in serotonin receptors. This case highlights the importance of considering subclinical Parkinson's disease in patients with duloxetine-associated parkinsonism.

Collective Total Synthesis of Four Ganoderma Meroterpenoids Based on an Intramolecular Aldol Strategy.

The total synthesis of four Ganoderma meroterpenoids (lingzhiol, sinensilactam A, lingzhilactone B, and applanatumol I) has been accomplished from a known olefinic lactone in much shorter steps (4-8 steps) and markedly improved overall yields (15-27%) compared to previous syntheses. The key steps are highly regio- and diastereoselective intramolecular aldol reactions to prepare bicyclic lactone intermediates and a decarboxylative radical cyclization to install the unique tetracyclic ring system of lingzhiol.

Lake shape and the characteristics of migration behavior modify Atlantic salmon smolt migration success through lakes.

Migration is a high-risk behavior. For the Atlantic salmon, Salmo salar, migrating from its river nursery area to marine feeding grounds, the magnitude of risk varies with habitat type. Passage through lakes, in particular, is associated with low rates of migration success. Downstream migrating salmon smolts are rheotactic when migrating in rivers, but lakes typically provide poorer directional currents for migrating salmon. In this study we tested if, in the absence of clear navigational cues in lakes, Atlantic salmon smolts switch to a random search strategy to find the outflowing river. We constructed random search simulations to test if lake basin shape has an effect on migration success. We also compared simulated migration characteristics with migrations of salmon smolts through five real lakes for which there are telemetry data for migrating salmon. Correlated random walk simulations showed that a random search strategy could be successful for all lake shapes tested but was more successful in curved (round and elliptical) than rectangular basin shapes. Rectangular basins with the migration start and stoppoints at the ends of the lake had a higher success than those where these points were perpendicular to the axis of the lake. In general, a random walk model predicted the migration success rate of fish tracked through real lakes. However, for two lakes the simulated migration success exceeded that of actual success, suggesting that fish passing through these lakes were not adopting a random search strategy. We speculate that this is the result of either conflicting navigational cues which inhibit smolts from finding the lake outlet or that they temporarily suspend migration (e.g., to feed). Modelling predicted that for small lakes, directional swimming in short steps (ca. 100 m) followed by turns with very low variation from the direction of travel resulted in the highest migration success. For larger lakes, longer step lengths but also with low turn variation (simulated turning angle drawn from distributions of standard deviation 2° and 5° around a mean of 0°) resulted in the highest migration success. We conclude that navigation in downstream migrating salmon smolts switches from rheotaxis in rivers to a random search tactic in lakes except where residual flow cues in some lakes prevent this, at times resulting in suboptimal navigation outcomes.

Computer model for gait assessments in Parkinson's patients using a fuzzy inference model and inertial sensors.

Computer model for gait assessments in Parkinson's patients using a fuzzy inference model and inertial sensors.

Effects of Step Length and Stride Variation During Forward Lunges on Lower-Extremity Muscle Activity.

The forward lunge is a closed-chain weight-bearing multi-joint exercise simulating the activities of daily living, such as walking or stair climbing, which mainly activates hip, knee, and ankle musculature and is also used by athletes and other individuals to train lower-extremity musculature. The purpose of this study is to compare lower-extremity muscle recruitment patterns between stride and step length variations in forward lunges. Twenty participants had a mean (±SD) age, mass, and height of 26 ± 6 y, 79 ± 8 kg, and 176 ± 7 cm, respectively, for males, and 27 ± 4 y, 62 ± 6 kg, and 161 ± 7 cm, respectively, for females. All participants used their 12-repetition maximum weight while performing a short step and long step forward lunge with a stride (striding forward and pushing back to the starting position) and without a stride (lunging up and down with feet stationary). During each lunge variation, surface electromyography (EMG) data were collected from the quadriceps, hamstrings, gastrocnemius, hip adductors, gluteus maximus, and gluteus medius muscles, and then normalized as a percent of each muscle's maximum voluntary isometric contraction. A repeated measures two-way analysis of variance was employed (p < 0.01), with step length and stride comprising the two factors. The following had no significant interactions: (1) quadriceps, hamstrings, gastrocnemius, hip adductor, and gluteus maximus EMG activities were significantly greater in lunges with a long step compared to lunges with a short step; and (2) gluteus maximus and gluteus medius EMG activities were significantly greater in lunges with a stride compared to lunges without a stride. The following had significant interactions: (1) gluteus medius EMG activities were significantly greater in lunges with a long step with and without a stride compared to lunges with a short step with and without a stride; (2) quadriceps EMG activities were generally significantly greater in lunges with long and short steps with a stride compared to lunges with long and short steps without a stride, in lunges with a long step with a stride compared to lunges with a short step with a stride, and in lunges with a short step without a stride compared to lunges with a long step without a stride; (3) hamstring and hip adductor EMG activities were significantly greater in lunges with a long step with a stride compared to lunges with a long step without a stride, and in lunges with a long step with and without a stride compared to lunges with a short step with and without a stride; and (4) gastrocnemius EMG activities were significantly greater in lunges with a long step with and without a stride compared to lunges with a short step with and without a stride. Lower-extremity muscle activity is generally greater in forward lunges with a long step compared to a short step, and greater in lunges with a stride compared to without a stride. During the externally loaded forward lunge, high to very high muscle activity occurs in the quadriceps, gluteus maximus, and gluteus medius, thus enhancing muscle hypertrophy and strength in these muscles, while moderate muscle activity occurs in the hamstrings, gastrocnemius, and adductor longus.

Krylov complexity and Trotter transitions in unitary circuit dynamics

We investigate many-body dynamics where the evolution is governed by unitary circuits through the lens of “Krylov complexity,” a recently proposed measure of complexity and quantum chaos. We extend the formalism of Krylov complexity to unitary circuit dynamics and focus on Floquet circuits arising as the Trotter decomposition of Hamiltonian dynamics. For short Trotter steps the results from Hamiltonian dynamics are recovered, whereas a large Trotter step results in different universal behavior characterized by the existence of local : operators with vanishing autocorrelation functions, as exemplified in dual-unitary circuits. These operators exhibit maximal complexity growth, act as a memoryless bath for the dynamics, and can be directly probed in current quantum computing setups. These two regimes are separated by a crossover in chaotic systems. Conversely, we find that free integrable systems exhibit a nonanalytic transition between these different regimes, where maximally ergodic operators appear at a critical Trotter step. Published by the American Physical Society 2025

Disturbed hierarchy and mediation in reward-related circuits in depression.

Disturbed hierarchy and mediation in reward-related circuits in depression.

Completing the Asymptotic Classification of Mostly Symmetric Short Step Walks in an Orthant

Completing the Asymptotic Classification of Mostly Symmetric Short Step Walks in an Orthant

Faster Sampling in Molecular Dynamics Simulations with TIP3P-F Water.

The need for short time steps currently limits routine atomistic molecular dynamics (MD) simulations to the microsecond time scale. For long time steps, the numerical integration of the equations of motion becomes unstable, resulting in catastrophic crashes. Here, we combine mass repartitioning and rescaling to construct a water model that increases the sampling efficiency in biomolecular simulations without compromising integration stability and with preserved structural and thermodynamic properties. The resulting "fast water" is then used with a time step as before in combination with standard force fields. The reduced water viscosity and faster diffusion result in proportionally faster sampling of the larger-scale motions in the conformation space of both solute and solvent. We illustrate this approach by developing TIP3P-F based on the popular TIP3P model of water. A roughly 2-fold boost in the sampling efficiency at minimal cost in accuracy is substantial and helps lower the energy impact of large-scale MD simulations. The approach is general and can readily be applied to other water models and different types of solvents.

LANDSLIDE DISASTER MITIGATION BASED ON DISASTER RISK LEVEL IN GRESIK, EAST JAVA

Landslides are a natural disaster with a serious threat in Indonesia, especially in areas with vulnerable geographic conditions. Gresik Regency, East Java, is one such area that is prone to landslides. This research aims to identify mitigation measures that are appropriate to the level of landslide risk in Gresik Regency. The research method used is a descriptive approach by collecting secondary data from various reports and available data. The research results show that the proposed solution is to install an internet-based landslide Early Warning System (EWS) in locations that are prone to ground movement and landslides. This EWS is based on standard disaster risk assessment parameters, such as slope slope, slope direction, rock type, etc., which are adapted to regional conditions in Gresik Regency. Installation of this internet-based EWS has several innovative values, including providing added value for the organization and stakeholders, innovation in technology, can be replicated, can be applied sustainably, is in line with organizational values, and provides benefits to the organization. Short, medium and long-term activity stages are outlined to achieve successful implementation, including installing EWS, developing the latest formats and applications, as well as monitoring and outreach. The installation of an internet-based landslide EWS in Gresik Regency is an innovative step that has great potential to increase preparedness and reduce the impact of landslides. This EWS is in line with the values ​​of BPBD Gresik Regency and can be replicated by other agencies. Successful implementation depends on short, medium and long term planning steps, as well as ongoing efforts in system development and outreach to the community. It is hoped that this research can contribute to reducing the impact of landslides in Gresik Regency and similar areas in the future.

Negative effect and removal of trace amounts of 1,3-dialkylimidazolium ionic liquids in samples from biorefineries

Ionic liquids (ILs), based on 1,3-dialkylimidazolium cations, are frequently used solvent components or auxiliaries for various types of biomass in biorefinery approaches. Unless washing and sample preparation have been carried out very carefully, analytical samples often contain residual traces of such ionic liquids. These residues can compromise the quality of physicochemical analyses, as was demonstrated for monosaccharide analysis after hydrolysis by gas chromatography, high-performance thin-layer chromatography, or ion chromatography (IC), and even damage analytical equipment, such as gas chromatographic capillaries or IC electrodes. We suggest a simple procedure—short stirring with solid elemental sulfur adsorbed on alumina as the scavenger—as a pretreatment of the analytical samples to remove interfering imidazolium IL traces. The chemistry underlying this pretreatment is the conversion of the 1,3-dialkylimidazolium cation to the corresponding, water-insoluble, neutral, volatile 1,3-dialkylimidazole-2-thiones. Given the negative effect of imidazolium IL impurities, the minor extension of the sample preparation by one short additional step appears to be a small price to pay for an unperturbed and instrument-safe analysis.Graphical abstract

Tutorial on Molecular Latent Space Simulators (LSSs): Spatially and Temporally Continuous Data-Driven Surrogate Dynamical Models of Molecular Systems.

The inherently serial nature and requirement for short integration time steps in the numerical integration of molecular dynamics (MD) calculations place strong limitations on the accessible simulation time scales and statistical uncertainties in sampling slowly relaxing dynamical modes and rare events. Molecular latent space simulators (LSSs) are a data-driven approach to learning a surrogate dynamical model of the molecular system from modest MD training trajectories that can generate synthetic trajectories at a fraction of the computational cost. The training data may comprise single long trajectories or multiple short, discontinuous trajectories collected over, for example, distributed computing resources. Provided the training data provide sufficient sampling of the relevant thermodynamic states and dynamical transitions to robustly learn the underlying microscopic propagator, an LSS furnishes a global model of the dynamics capable of producing temporally and spatially continuous molecular trajectories. Trained LSS models have produced simulation trajectories at up to 6 orders of magnitude lower cost than standard MD to enable dense sampling of molecular phase space and large reduction of the statistical errors in structural, thermodynamic, and kinetic observables. The LSS employs three deep learning architectures to solve three independent learning problems over the training data: (i) an encoding of the high-dimensional MD into a low-dimensional slow latent space using state-free reversible VAMPnets (SRVs), (ii) a propagator of the microscopic dynamics within the low-dimensional latent space using mixture density networks (MDNs), and (iii) a generative decoding of the low-dimensional latent coordinates back to the original high-dimensional molecular configuration space using conditional Wasserstein generative adversarial networks (cWGANs) or denoising diffusion probability models (DDPMs). In this software tutorial, we introduce the mathematical and numerical background and theory of LSS and present example applications of a user-friendly Python package software implementation to alanine dipeptide and a 28-residue beta-beta-alpha (BBA) protein within simple Google Colab notebooks.

Identification of distinct subtypes of post-stroke and neurotypical gait behaviors using neural network analysis of kinematic time series data.

Heterogeneous types of gait impairment are common post-stroke. Studies used supervised and unsupervised machine learning on discrete biomechanical features to summarize the gait cycle and identify common patterns of gait behaviors. However, discrete features cannot account for temporal variations that occur during gait. Here, we propose a novel machine-learning pipeline to identify subgroups of gait behaviors post-stroke using kinematic time series data. We analyzed ankle and knee kinematic data during treadmill walking data in 39 individuals post- stroke and 28 neurotypical controls. The data were first input into a supervised dual-stage Convolutional Neural Network-Temporal Convolutional Network, trained to extract temporal and spatial gait features. Then, we used these features to find clusters of different gait behaviors using unsupervised time series k-means. We repeated the clustering process using 10,000 bootstrap training data samples and a Gaussian Mixture Model to identify stable clusters representative of our dataset. Finally, we assessed the kinematic differences between the identified clusters using 1D statistical parametric mapping ANOVA. We then compared gait spatiotemporal and clinical characteristics between clusters using one-way ANOVA. We obtained five clusters: two clusters of neurotypical individuals (C1 and C2) and three clusters of individuals post-stroke (S1, S2, S3). C1 had kinematics that resembled the normative gait pattern. Individuals in C2 had a shorter stride time than C1. Individuals in S1 had mild impairment and walked with increased bilateral knee flexion during the loading response. Individuals in S2 had moderate impairment, were the slowest among the clusters, took shorter steps, had increased knee flexion during stance bilaterally and reduced paretic knee flexion during swing. Individuals in S3 had mild impairment, asymmetric swing time, had increased ankle abduction during the gait cycle and reduced dorsiflexion bilaterally during loading response and stance. Every individual was assigned to a cluster with a cluster membership likelihood above 93%. Our results indicate that joint kinematics in individuals post-stroke are distinct from controls, even in those individuals with mild impairment. The three subgroups post-stroke showed distinct kinematic impairments during specific phases in the gait cycle, providing additional information to clinicians for gait retraining interventions.

Wind effects on individual male and female Bactrocera jarvisi (Diptera: Tephritidae) tracked using harmonic radar.

Wind affects the movement of most volant insects. While the effects of wind on dispersal are relatively well understood at the population level, how wind influences the movement parameters of individual insects in the wild is less clear. Tephritid fruit flies, such as Bactrocera jarvisi, are major horticultural pests worldwide and while most tephritids are nondispersive when host plants are plentiful, records exist for potentially wind-assisted movements up to 200 km. In this study, harmonic radar (HR) was used to track the movements of both male and female lab-reared B. jarvisi in a papaya field. Overall flight directions were found to be correlated with wind direction, as were the subset of between-tree movements, while within-tree movements were not. Furthermore, the effect of wind direction on fly trajectories varied by step-distance but not strongly with wind speed. Mean path distance, step distance, flight direction, turning angle, and flight propensity did not vary by sex. Both male and female movements are well fit by 2-state hidden Markov models further supporting the observation that B. jarvisi move differently within (short steps with random direction) and between (longer more directional steps) trees. Data on flight directionality and step-distances determined in this study provide parameters for models that may help enhance current surveillance, control, and eradication methods, such as optimizing trap placements and pesticide applications, determining release sites for parasitoids, and setting quarantine boundaries after incursions.

Visible-light-promoted direct desulfurization of glycosyl thiols to access C-glycosides

C-Glycosides are essential for the study of biological processes and the development of carbohydrate-based drugs. Despite the tremendous hurdles, glycochemists have often fantasized about the efficient, highly stereoselective synthesis of C-glycosides with the shortest steps under mild conditions. Herein, we report a desulfurative radical protocol to synthesize C-alkyl glycosides and coumarin C-glycosides under visible-light induced conditions without the need of an extra photocatalyst, in which stable and readily available glycosyl thiols that could be readily obtained from native sugars are activated in situ by pentafluoropyridine. The benefits of this procedure include high stereoselectivity, broad substrate scope, and easy handling. Mechanistic studies indicate that the in situ produced tetrafluoropyridyl S-glycosides form key electron donor–acceptor (EDA) complexes with Hantzsch ester (for C-alkyl glycosides) or Et3N (for coumarin C-glycosides), which, upon irradiation with visible light, trigger a cascade of glycosyl radical processes to access C-glycosides smoothly.

Factors Influencing Gait Performance: Comfortable Linear Gait and Complex Gait in School-Aged Children in a Dual-Task Model

The aim of this study was to determine the effect of cognitive interference by using the Dual-Task (DT) paradigm on gait parameters according to sex, and age. Additionally, we aim to explore the relationship between Dual-Task-Cost (DTC), physical fitness, cognitive functioning, and weight status in schoolchildren. One hundred schoolchildren participated in this study (age = 8.83 ± 1.82 years). They were randomly assigned to Comfortable Linear Gait (CLG: gait in a straight path) or Complex Gait (CG: gait over obstacles) with and without interference. For CLG, boys and girls showed a reduction in gait speed (p < 0.001), cadence (p < 0.01), and step length (p < 0.001). In addition, double support time (p < 0.05) and cadence coefficient of variance (boys= p < 0.01; girls= p < 0.05) increased in the DT condition. In the CG, both sexes (p < 0.001) exhibited a worse execution time. There were significant effects on speed DTC between 8-9 vs. 10-11 years in CLG and 6-7 vs. 10–11 years in CGT (p < 0.05). In conclusion, gait parameters during CLG and CG are modified in the DT condition, resulting in a slower gait with shorter steps, regardless of age and sex. DTC is associated with physical fitness and cognitive function.

Cerebellar cortical degeneration in ‘Cirneco dell'Etna’ dog: First case report

AbstractA 4‐month‐old, intact male, Cirneco dell'Etna dog was presented with clinical signs of cerebellar ataxia, hindlimb hypometry and short steps with rapid progression. No findings were obtained from blood examinations, magnetic resonance imaging and cerebrospinal fluid (CSF) examinations and the dog was euthanased when it was not able to walk. Histological examination and immunohistochemical staining of the cerebellum showed multifocal depletion of Purkinje cells, marked increase in cellularity (astrogliosis) and a moderate reduction of the cells of the granule layer and thinning of the molecular layer. This case report describes the first case of cerebellar cortical degeneration in a purebreed Cirneco dell'Etna dog.

Hopping and crawling DNA-coated colloids

Understanding the motion of particles with multivalent ligand-receptors is important for biomedical applications and material design. Yet, even among a single design, the prototypical DNA-coated colloids, seemingly similar micrometric particles hop or roll, depending on the study. We shed light on this problem by observing DNA-coated colloids diffusing near surfaces coated with complementary strands for a wide array of coating designs. We find colloids rapidly switch between 2 modes: They hop-with long and fast steps-and crawl-with short and slow steps. Both modes occur at all temperatures around the melting point and over various designs. The particles become increasingly subdiffusive as temperature decreases, in line with subsequent velocity steps becoming increasingly anticorrelated, corresponding to switchbacks in the trajectories. Overall, crawling (or hopping) phases are more predominant at low (or high) temperatures; crawling is also more efficient at low temperatures than hopping to cover large distances. We rationalize this behavior within a simple model: At lower temperatures, the number of bound strands increases, and detachment of all bonds is unlikely, hence, hopping is prevented and crawling favored. We thus reveal the mechanism behind a common design rule relying on increased strand density for long-range self-assembly: Dense strands on surfaces are required to enable crawling, possibly facilitating particle rearrangements.

Effects of the social environment on movement-integrated habitat selection

BackgroundMovement links the distribution of habitats with the social environment of animals using those habitats. Despite the links between movement, habitat selection, and socioecology, their integration remains a challenge due to lack of shared vocabulary across fields, methodological gaps, and the implicit (rather than explicit) historical development of theory in the fields of social and spatial ecology. Given these challenges can be addressed, opportunity for further study will provide insight about the links between social, spatial, and movement ecology. Here, our objective was to disentangle the roles of habitat selection and social association as drivers of movement in caribou (Rangifer tarandus).MethodsTo accomplish our objective, we modelled the relationship between collective movement and selection of foraging habitats using socially informed integrated step selection function (iSSF). Using iSSF, we modelled the effect of social processes, i.e., nearest neighbour distance and social preference, and movement behaviour on patterns of habitat selection.ResultsBy unifying social network analysis with iSSF, we identified movement-dependent social association, where individuals took shorter steps in lichen habitat and foraged in close proximity to more familiar individuals.ConclusionsOur study demonstrates that social preference is context-dependent based on habitat selection and foraging behaviour. We therefore surmise that habitat selection and social association are drivers of collective movement, such that movement is the glue between habitat selection and social association. Here, we put these concepts into practice to demonstrate that movement is the glue connecting individual habitat selection to the social environment.

Image-driven prediction of fatigue crack growth in metal materials via spatiotemporal neural network

Image-driven prediction of fatigue crack growth in metal materials via spatiotemporal neural network