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The effect of asymmetrical body-mass distribution on the stability and dynamics of two-degree-of-freedom quadruped bounding in place is investigated in this study. An analytical stability criterion for bounding of quadrupeds with asymmetrical mass distribution is developed. Bounding is found to be passively stable in the Hamiltonian sense when the dimensionless pitch moment of inertia of the body is less than 1 - [[beta].sup.2], where [beta] is a dimensionless measure of the asymmetry. The criterion is derived under the assumptions of infinite leg stiffness and no energy loss. With energy dissipation modeled as linear damping in the legs, simulation results show that the criterion is independent of the value of leg stiffness and a conservative estimate of the critical inertia value. Body symmetry appears to be more favorable to stable bounding than asymmetry, but only slightly so in practicality. The results show that asymmetry offers some advantages when the dynamic characteristics of bounding are compared for symmetrical and asymmetrical models. Lower stride frequency, larger vertical displacement, and smaller duty factor are obtained with this more animal-like model. Index Terms--Asymmetry, bounding, dynamics, legged locomotion, quadruped, stability.

The central complex, a set of neuropils in the center of the insect brain, plays a crucial role in spatial aspects of sensory integration and motor control. Stereotyped neurons interconnect these neuropils with one another and with accessory structures. We screened over 5,000 Drosophila melanogaster GAL4 lines for expression in two neuropils, the noduli (NO) of the central complex and the asymmetrical body (AB), and used multicolor stochastic labeling to analyze the morphology, polarity, and organization of individual cells in a subset of the GAL4 lines that showed expression in these neuropils. We identified nine NO and three AB cell types and describe them here. The morphology of the NO neurons suggests that they receive input primarily in the lateral accessory lobe and send output to each of the six paired noduli. We demonstrate that the AB is a bilateral structure which exhibits asymmetry in size between the left and right bodies. We show that the AB neurons directly connect the AB to the central complex and accessory neuropils, that they target both the left and right ABs, and that one cell type preferentially innervates the right AB. We propose that the AB be considered a central complex neuropil in Drosophila. Finally, we present highly restricted GAL4 lines for most identified protocerebral bridge, NO, and AB cell types. These lines, generated using the split‐GAL4 method, will facilitate anatomical studies, behavioral assays, and physiological experiments. The authors use the multicolor flip‐out strategy in Drosophila to analyze neurons in two neuropils: the noduli of the central complex and the asymmetrical body. A set of split‐GAL4 lines is provided for previously published protocerebral bridge cell types as well as cell types presented here. [ABSTRACT FROM AUTHOR]

Unilateral vestibular lesion results in postural balance deficits, which progressively vanish with time compensation. This functional recovery is caused due to the reorganization of the CNS structures and afferent inputs, mainly of the proprioceptive afferentation. Our aim was to determine the postural effect of leg proprioceptive input induced by the Achilles tendon (AT) vibration in standing patients with unilateral vestibular hypofunction. The examined patients (9 patients unilateral vestibular neuritis and 3 patients with Meniere's disease) had unilaterally decreased caloric responses. The control were 20 healthy volunteers with intact vestibular and motor functions. The postural responses evoked by AT vibration were evaluated by the symmetry of centre of pressure (COP) of the subject. The postural responses induced by the AT vibration in the healthy were bilaterally symmetrical. In the patients the body lean evoked by vibration on the side of intact vestibular apparatus was significantly decreased. The AT vibration on the lesioned side evoked practically identical response to the response of healthy subjects. In the repeated examination after 6 months the asymmetry disappeared which was in accordance with the recovered clinical state. The findings of asymmetry of postural COP displacement in patients with acute unilateral vestibular hypofunction documented transitory asymmetry of influence from leg proprioceptive inputs. The direction of decreased postural response to the proprioceptive stimuli was the same as pathological body lean of patient to the side of lesioned vestibular apparatus. This fact allows us to hypothesize that the postural responses evoked by leg proprioceptive inputs, directionally identical with the pathological body lean induced by asymmetry of vestibular afferentation are inhibited. (Fig. 3, Ref. 15.)

Lateral recumbency causes ipsilateral nasal congestion and contralateral decongestion. Nasal resistances were measured before, during and after the application of pressure either regionally or by lateral recumbency. In some experiments an attempt was made to block the response by local anesthetic injection, splinting the nasal vestibules, or topical decongestants. In others an electric blanket was employed as a stimulus instead of pressure. It was concluded that the nasal resistance changes during lateral recumbency are due to pressure receptors in the pelvic and pectoral girdles, and thorax. These adapt slowly. They are probably situated in the intercostal spaces, parietal pleura, or sterno-costal joints. Their centripetal fibers probably travel in the intercostal nerves, and their efferents in the cervical sympathetic outflow to the nasal erectile tissue. Lateral recumbency of 12 minutes' duration induces changes in nasal resistance which persist after the pressure asymmetry has been terminated. This may be due to temporal summation.

Background: The purpose of the present study was to determine the impact of the direction and magnitude of primary lateral spinal curvature in children with scoliosis. Methods: Ninety-six children diagnosed with scoliosis were included in the study group, and fifty healthy peers were included in the control group. Posturographic measurements of body weight distribution and posturometric tests with eyes open and closed were performed. Results: Based on the symmetry index values, the study group was divided into children with symmetrical and asymmetrical body weight distributions on the basis of support. Then, taking into account the direction of the primary curvature, children with asymmetrical body weight distributions were divided into: (1) children with left-sided or right-sided scoliosis with overload on the same side of the body; and (2) children with left-sided or right-sided scoliosis with overload on the opposite side of the body. According to both posturometric tests, increased CoP spatial displacement was observed in the children with scoliosis compared to the healthy controls. The obtained results showed that increased asymmetry index and Cobb angle values significantly increase medial–lateral postural instability in children with scoliosis. Conclusions: These findings suggest that treatment to restore symmetric body weight distribution may prevent the progression of postural instability; however, this requires confirmation through further investigation. [ABSTRACT FROM AUTHOR]

Organophosphate pesticides, especially chlorpyrifos, are one of the most widely used insecticides in agriculture, but their toxicity and potential sensitivity effects on Anura, especially Fejervarya limnocharis are still unknown. The purpose of this investigation is to study F. limnocharis (Anura: Dicroglossidae) tadpole sensitivity to lethal (survivability) and sublethal effects (morphological alterations and swimming activity) of chlorpyrifos in Dursban 200EC commercial formula under acute exposure. An acute toxicity test was carried out on ten tadpoles (Gosner 25) in each repetition. The sample was obtained from artificial reproduction by injecting the Trial Batch 2000 IU hCG by Kings Lab. The acute toxicity testing consisted of three replicates with a chlorpyrifos concentration of 0; 0.4; 0.8; 1; 2; 4; and 8 µg/L. Physico-chemical parameters, mortality, morphological, and swimming alterations of each concentration were observed at 24th, 48th, 72nd, and 96th hours. The LC50 of chlorpyrifos for F. limnocharis tadpoles was 2.86 µg/L. The percentage of survivability F. limnocharis tadpoles decreased after exposure to chlorpyrifos above 1µg/L, while morphological alterations were observed in 2 µg/L and 4 µg/L after 48th hours exposure, and the swimming alterations have occurred at 24th hours in 1; 2; 4 and 8 µg/L. Morphological alterations were observed including asymmetrical body shape, edema, and abnormal tail shape. Based on the LC50 value, commercial chlorpyrifos has high-level toxicity on F. limnocharis tadpoles. [ABSTRACT FROM AUTHOR]

Paralichthys olivaceus is the kind of cold-water benthic marine fish. In the early stages of development, the symmetrical juveniles transform into an asymmetrical body shape through metamorphosis for adapting benthic life. After that, one side of the fish body is attached to the ground, and the eyes turn to the opposite side which is called ocular side. The body color also appears asymmetry. The skin on the ocular side is dark brown, and the skin on the blind side is white without pigmentation. Pseudo-albinism and hypermelanosis have been considered distinct body color disorders in flatfish. Pseudo-albinism and hypermelanosis in Paralichthys olivaceus are due to abnormal or uneven pigment distribution, due to the interaction of hereditary and environmental factors, rather than a single-nucleotide mutation of a specific gene. Here, we report three single-nucleotide polymorphisms (SNPs) responsible for both pseudo-albinism and hypermelanosis, which are located on two body color-related genes involved in melanogenesis-related pathways. c.2440C>A (P. V605I) and c.2271-96T>C are located on the Inositol 1,4,5-trisphosphate receptor type 2-like (ITPR2) (Gene ID: 109624047), they are located in exon 16 and the non-coding region, respectively, and c.2406C>A (P.H798N) is located in exon 13 of the adenylate cyclase type 6-like (AC6) gene(Gene ID: 109630770). ITPR2 and AC6 expression, which both participate in the thyroid hormone synthesis pathway associated with pseudo-albinism and hypermelanosis in P. olivaceus, were also investigated using qRT-PCR. In hypermelanotic fish, there were relatively higher levels of expression in ITPR2 and AC6 mRNA of hyper-pigmented skin of blind side than that of non-pigmented skin on the blind side and pigmented skin on the ocular side, while in pseudo-albino fish, expression level of ITPR2 and AC6 mRNA in pigmented skin of ocular side was significantly higher than that in non-pigmented skin both ocular and blind side. The results indicated that the expression of the two genes in abnormal parts of body color is positively correlated with pigmentation, suggesting that the influence of abnormal expression of two genes on the pigmentation in abnormal parts of body color deserves further study. [ABSTRACT FROM AUTHOR]

Reconstructing the function and behaviour of extinct groups of echinoderms is problematic because there are no modern analogues for their aberrant body plans. Cinctans, an enigmatic group of Cambrian echinoderms, exemplify this problem: their asymmetrical body plan differentiates them from all living species. Here, we used computational fluid dynamics to analyse the functional performance of cinctans without assuming an extant comparative model. Three‐dimensional models of six species from across cinctan phylogeny were used in computer simulations of water flow. The results demonstrate that cinctans with strongly flattened bodies produced much less drag than species characterized by dorsal protuberances or swellings, suggesting the former were more stable on the seafloor. However, unlike the flattened forms, cinctans with high‐relief bodies were able to passively direct flow towards the mouth and associated food grooves, indicating that they were capable of more efficient feeding on particles suspended in the water. This study provides evidence of a previously unknown evolutionary trade‐off between feeding and stability in Cambrian cinctan echinoderms. [ABSTRACT FROM AUTHOR]

Taking advantage of the good mechanical strength of expanded Drosophila brains and to tackle their relatively large size that can complicate imaging, we apply potassium (poly)acrylate-based hydrogels for expansion microscopy (ExM), resulting in a 40x plus increased resolution of transgenic fluorescent proteins preserved by glutaraldehyde fixation in the nervous system. Large-volume ExM is realized by using an axicon-based Bessel lightsheet microscope, featuring gentle multi-color fluorophore excitation and intrinsic optical sectioning capability, enabling visualization of Tm5a neurites and L3 lamina neurons with photoreceptors in the optic lobe. We also image nanometer-sized dopaminergic neurons across the same intact iteratively expanded Drosophila brain, enabling us to measure the 3D expansion ratio. Here we show that at a tile scanning speed of ~1 min/mm3 with 1012 pixels over 14 hours, we image the centimeter-sized fly brain at an effective resolution comparable to electron microscopy, allowing us to visualize mitochondria within presynaptic compartments and Bruchpilot (Brp) scaffold proteins distributed in the central complex, enabling robust analyses of neurobiological topics. Combining expansion microscopy (ExM) with lightsheet imaging can enable fast 3D visualisation of biological structures at high-resolution, but such approaches can be hindered by several limitations. By using potassium acrylate-based hydrogels, the authors perform large-volume ExM with Bessel lightsheet microscopy, achieving high-resolution imaging of cellular structures within the fly brain. [ABSTRACT FROM AUTHOR]

Background: Numerous scoliosis research studies have investigated postural control changes in adolescents with idiopathic scoliosis and compared them to healthy controls. However, the results have been controversial. Therefore, the present study aimed to compare whether postural control in adolescent idiopathic scoliosis (AIS) patients is different from their age-matched healthy counterparts. Methods: An exploratory cross-sectional study was conducted comprising 121 adolescents (11 to 17 years) divided into five groups, including those diagnosed with idiopathic scoliosis (n = 95) and healthy control peers (n = 26). According to the type (single or double), location (thoracic or lumbar), and severity (mild = Cobb's angle ≤ 25°, moderate = 26° ≤ Cobb's angle ≥ 45°) of AIS, the groups included: group 1: mild single curve in the thoracic region, group 2: mild single curve in the lumbar region, group 3: mild double curves, group 4: moderate double curves, and group 5: healthy control. Computerized Dynamic Posturography (CDP)/ /NeuroCom International, Inc., Clackamas, OR, USA was used to assess the postural control parameters. The assessment included the Sensory Organization Test (SOT), the Adaptation Test (ADT), the Motor Control Test (MCT), the Weight-Bearing Squat test (WBS), and finally the Unilateral Stance Test (UST). Results: The study analyzed data from 121 participants (36 boys, 85 girls) across five groups. No significant differences were found between the AIS and control groups concerning the type of curve or when comparing single and double curves. A one-way ANOVA indicated that variables related to the SOT were normally distributed, while other tests did not show normal distribution. Comparisons controlled for BMI, curve type (single or double), and severity of the major curve revealed no significant differences in postural control variables between AIS and control groups. Notable p-values include SOT 1 (p = 0.964), SOTstrategy 1 (p = 0.192), SOT 2 (p = 0.733), SOTstrategy 2 (p = 0.497), SOT 3 (p = 0.057), SOTstrategy 3 (p = 0.693), MCT (p = 0.089), USleftOpen (p = 0.087), and USrightOpen (p = 0.057). Conclusion: This study's findings indicated that there were no statistically significant differences in postural control when performing activities of daily living among adolescents with idiopathic scoliosis compared to their healthy aged-matched peers. Therefore, there is no need for additional training to improve postural control in these adolescents with idiopathic scoliosis. However, the importance of identifying the postural control mechanisms in these populations is considerable for treating scoliosis. [ABSTRACT FROM AUTHOR]

Accurate navigation often requires the maintenance of a robust internal estimate of heading relative to external surroundings. We present a model for angular velocity integration in a desert locust heading circuit, applying concepts from early theoretical work on heading circuits in mammals to a novel biological context in insects. In contrast to similar models proposed for the fruit fly, this circuit model uses a single 360° heading direction representation and is updated by neuromodulatory angular velocity inputs. Our computational model was implemented using steady-state firing rate neurons with dynamical synapses. The circuit connectivity was constrained by biological data, and remaining degrees of freedom were optimised with a machine learning approach to yield physiologically plausible neuron activities. We demonstrate that the integration of heading and angular velocity in this circuit is robust to noise. The heading signal can be effectively used as input to an existing insect goal-directed steering circuit, adapted for outbound locomotion in a steady direction that resembles locust migration. Our study supports the possibility that similar computations for orientation may be implemented differently in the neural hardware of the fruit fly and the locust. Author summary: In both fruit flies and locusts, a specific brain region shows an activity pattern that resembles a compass, with an activity peak moving across an array of neurons as the animal rotates through 360 degrees. However, some apparent differences in the properties of this pattern between the two species suggest there may be differences in how this internal compass is implemented. Here we focus on the locust brain, building a computational model that is based on observed neural connections and using machine learning to tune the system. Turning by the simulated locust provides modulatory input to the neural circuit that keeps activity in the array aligned to its heading direction. We simulate a migrating locust that tries to keep the same heading despite perturbances and show this circuit can steer it back on course. Our model differs from existing models of the fruit fly compass, showing how similar computations could have different implementations in different species. [ABSTRACT FROM AUTHOR]

For judo athletes with visual impairments and their coaches, understanding possible muscle adaptations can be challenging. As it is commonplace for these adaptations to include interlimb asymmetry, we analyzed the magnitude and direction of interlimb asymmetry in judo athletes with visual impairments and verified the association of this asymmetry with their unilateral physical performances. Participants were 18 elite judo athletes (10 male, 8 female) with visual impairments. These athletes performed three physical tests: countermovement jump (CMJ), medicine ball throw (MBT), and handgrip strength (HGS), while we conducted unilateral right and left side assessments using the interlimb asymmetry equation for each physical test. Our main results showed that the CMJ and MBT tests presented asymmetry values above 10%; with CMJ significantly higher than HGS (p = 0.050), and with inconsistencies across the three tests in the direction of interlimb asymmetry (k = −0.22–0.26). Unilateral CMJ (left limb) was negatively correlated with asymmetry (r = −0.51; p = 0.031), and unilateral MBT (right limb) was positively correlated with asymmetry (r = 0.52; p = 0.024). Based on these results, coaches should prioritize regular assessments of interlimb asymmetry using these specific tests. This data can guide the construction of training programs aimed at minimizing asymmetry and enhancing overall physical performance. Continuous monitoring and adjustment of training strategies based on asymmetry findings are crucial for optimizing muscle balance in judo athletes with visual impairments. [ABSTRACT FROM AUTHOR]

The 3D modeling analysis for the rotary motion of an asymmetric rigid body (RB) that gains a charge is presented. Under the effect of a gyrostatic moment (GM), an electromagnetic force field (EFF), time-varying body-fixed torques (TVBFTs), and constant axial torque (CAT), Euler's equation of motion (EOM) is derived to describe the body's EOM. The process is to derive the analytic solutions for the general attitude motion of the RB that is nearly symmetrical; therefore, a novel analytical solution for the angular velocities of the body has been approached. These new solutions are obtained by considering torques that vary over time and expressing them as integrals. Additionally, a novel closed-form evaluation mechanism for these integrals is offered. Specifically, the case of a constant torque around the spin axis and transverse torques represented by polynomial functions of time is explored. When dealing with an axisymmetric RB subject to a CAT, the solutions obtained from Euler's EOM are exact. However, it is important to note that novel analytic solutions for the Eulerian angles are approximations, as they rely on the assumption of small angles. Nonetheless, these approximations have broad applicability to a wide range of practical problems. The method's precision is demonstrated through the graphical simulation of the proposed solutions. Additionally, a computer program is utilized to create diagrams and phase plane curves, highlighting the contribution of various body parameters to the motion. These plots depict the contributions of various values regarding GM, charge, and CAT. Motion stability is also examined through phase diagrams. In addition to presenting novel solutions and outcomes for the problem, this study plays a vital role in multiple scientific and engineering fields as it has the potential to optimize mechanical systems, explain celestial motion, and improve spacecraft performance. [ABSTRACT FROM AUTHOR]

This study focuses on determining the required minimum-time (MT) for the spatial motion of a free rigid body (RB) experiencing gyrostatic moments (GMs) and viscous friction. The study assumes that the body's center of mass coincides with the original point of two Cartesian systems of coordinates. An optimal control law for slow motion is established, and the corresponding time and phase pathways are analyzed. The innovative results are presented for two new cases through various graphs highlighting the positive effects of the GMs. A comparison is achieved between the obtained results and previous outcomes that did not consider gyrostatic moments, showing remarkable consistency with slight deviations that are discussed. The practical applications of this study, which limits itself to using gyroscopic theory to maintain the stability and balance of vehicles in which gyroscopes are used, as well as figuring out the trajectory of aircraft and marine vehicles, are what make it noteworthy. [ABSTRACT FROM AUTHOR]

Alcohol consumption and addiction remain global health concerns, with significant loss of productivity, morbidity, and mortality. Drosophila melanogaster, a widely used model organism, offers valuable insights into the genetic and neuronal mechanisms underlying ethanol-induced behaviors (EIBs) such as sedation, recovery, and tolerance. This narrative review focuses on studies in the Drosophila model system suggesting an association between circadian rhythm genes as modulators of ethanol tolerance. Mutations in these genes disrupt both the circadian cycle and tolerance, underscoring the interplay between circadian rhythm and ethanol processing although the exact mechanisms remain largely unknown. Additionally, genes involved in stress response, gene expression regulation, neurotransmission, and synaptic activity were implicated in ethanol tolerance modulation. At the neuronal level, recent studies have highlighted the involvement of corazonin (CRZ) and neuropeptide F (NPF) neurons in modulating EIBs. Understanding the temporal dynamics of tolerance development is crucial for describing the molecular basis of ethanol tolerance. Ultimately, insights gained from Drosophila studies hold promise for elucidating the neurobiological underpinnings of alcohol use disorders and addiction, contributing to more effective interventions and treatments. [ABSTRACT FROM AUTHOR]

The early detection rate of breast cancer and its relative survival rate are persistently increasing, thanks to an active approach to breast cancer exams and enhancement of clinical treatment capabilities. In this new environment, quality-of-life breast reconstructive surgery for those who have undergone a mastectomy for breast cancer treatment has become ever-more attractive. However, there is a problem that occurs, where post-reconstruction breast shapes differ from those before mastectomy. This is caused by insufficient geometric information for the breasts to be reconstructed. Therefore, patients not only go on to suffer inconvenience in daily life, but they also experience a loss of psychological self-esteem owing to an asymmetrical body. In this study, we generate three-dimensional (3D) breast shapes by extracting geometric information from fat and fibro-glandular breast tissues from a series of magnetic resonance imaging images, which are acquired during pre-mastectomy examinations. We then apply a Neo-Hookean material model, which is a hyper-elastic material property model being considered for natural breast-shape deformability. We then use finite element analysis to model the 3D breast by accounting for its deformation characteristics, finally proposing a method to transform the model breast into a shape indicative of a natural, standing posture. [ABSTRACT FROM AUTHOR]

Fracture healing is usually monitored by clinical impressions and radiographs. Objective and easy methods for assessing fracture healing without radiation would be beneficial. The aim of this study was to analyse whether weight and plantar pressure while standing can be used to monitor healing of tibial or malleolar fractures and whether these parameters can discriminate between patients with and without union. Thirteen patients were longitudinally assessed during each postoperative clinical visit, of whom two developed a nonunion. Eleven matched healthy controls were assessed once. Additionally, five patients already experiencing nonunion were assessed once at the time of their nonunion diagnosis. All participants performed a standing task for ten seconds with pressure-sensing insoles. Greatest improvements were detected throughout the first three months in patients with union. However, six months after surgery, more than half of the parameters were still significantly different from those of the controls. The weight and pressure distributions did not differ between patients with or without union six months after surgery. A standing task can be used to monitor improvements in weight and pressure distribution throughout the healing process of tibial or malleolar fractures, but lacks potential to discriminate between patients with or without fracture union. [ABSTRACT FROM AUTHOR]

The fruit fly Drosophila melanogaster has emerged as a key model organism in neuroscience, in large part due to the concentration of collaboratively generated molecular, genetic and digital resources available for it. Here we complement the approximately 140,000 neuron FlyWire whole-brain connectome1 with a systematic and hierarchical annotation of neuronal classes, cell types and developmental units (hemilineages). Of 8,453 annotated cell types, 3,643 were previously proposed in the partial hemibrain connectome2, and 4,581 are new types, mostly from brain regions outside the hemibrain subvolume. Although nearly all hemibrain neurons could be matched morphologically in FlyWire, about one-third of cell types proposed for the hemibrain could not be reliably reidentified. We therefore propose a new definition of cell type as groups of cells that are each quantitatively more similar to cells in a different brain than to any other cell in the same brain, and we validate this definition through joint analysis of FlyWire and hemibrain connectomes. Further analysis defined simple heuristics for the reliability of connections between brains, revealed broad stereotypy and occasional variability in neuron count and connectivity, and provided evidence for functional homeostasis in the mushroom body through adjustments of the absolute amount of excitatory input while maintaining the excitation/inhibition ratio. Our work defines a consensus cell type atlas for the fly brain and provides both an intellectual framework and open-source toolchain for brain-scale comparative connectomics.A consensus cell type atlas for the fly brain provides both an intellectual framework and open-source toolchains for brain-scale comparative connectomics. [ABSTRACT FROM AUTHOR]

Although most animals appear symmetric externally, they exhibit chirality within their body cavity, i.e., in terms of asymmetric organ position, directional organ looping, and lateralized organ function. Left-right (LR) asymmetry is determined genetically by intricate molecular interactions that occur during development. Key genes have been elucidated in several species. There are common mechanisms in vertebrates and invertebrates, but some appear to exhibit unique mechanisms. This review focuses on LR asymmetry formation in invertebrates, particularly Drosophila, ascidians, and mollusks. It aims to understand the role of the genes that are key to creating LR asymmetry and how chirality information is converted/transmitted across the hierarchies from molecules to cells and from cells to tissues. [ABSTRACT FROM AUTHOR]