Significant Reduction In Amplitude Research Articles

Analyzing vibration transmission through cantilever systems using biomechanical and impact-responsive metamaterial structures

Vibration control in cantilever systems is a critical challenge in various engineering applications, where unwanted vibrations can lead to structural fatigue, reduced performance, and potential failure. This study investigates the effects of integrating biomechanical and impact-responsive metamaterials into cantilever systems to mitigate vibration transmission. The metamaterials, characterized by their adaptive stiffness and energy-absorbing properties, are strategically embedded in key structural components such as the arms, joints, and base. Through experimental analysis, this work assesses the reduction in vibration amplitude, shifts in natural frequency, enhanced damping capacity, energy absorption during impact, and strain reduction at critical points. The results show that the metamaterial-enhanced system achieves significant reductions in vibration amplitude, up to 40%, and increases in natural frequency by over 30%, minimizing the risk of resonance. Additionally, the damping ratio is improved by as much as 53%, while the energy absorption during impact is increased by up to 26%. Strain reduction at critical points reaches 24%, contributing to improved mechanical resilience. These findings demonstrate the potential of biomechanical and impact-responsive metamaterials in enhancing the dynamic performance of cantilever systems, offering a new approach to vibration mitigation in engineering applications.

Review Paper on Vibration Damping System Using Pendulum

Abstract: This paper explores the implementation and effectiveness of vibration damping systems utilizing pendulums, focusing on their ability to mitigate unwanted oscillations in various structures. Pendulum-based dampers operate on the principles of inertia and resonance, allowing them to counteract vibrations causedby dynamic loads, seismic events, and machinery operations. The study examines different configurations, including tuned mass dampers (TMDs) and nonlinear pendulum systems, highlighting their design, functionality,and specific applications in fields such as civil engineering, aerospace, and automotive industries. Through analytical modeling and experimental validation, the paper demonstrates the effectiveness of pendulum dampers in enhancing structural stability and occupant comfort. The results indicate significant reductions in vibration amplitude, showcasing the potential of these systems to improve the longevity andsafety of infrastructure. Furthermore, the discussion addresses the advantages of pendulum-based systems over conventional damping methods, emphasizing their adaptability and efficiency.In conclusion, this study underscores the importance of pendulum vibration damping systems as a viable solution for contemporary engineering challenges, paving the way for future research and development in vibration control technologies.

Viscoelastic modelling and analysis of two-dimensional woven CNT-based multiscale fibre reinforced composite material system

Carbon nanotube (CNT) has fostered research as a promising nanomaterial for a variety of applications due to its exceptional mechanical, optical, and electrical characteristics. The present article proposes a novel and comprehensive micromechanical framework to assess the viscoelastic properties of a multiscale CNT-reinforced two-dimensional (2D) woven hybrid composite. It also focuses on demonstrating the utilisation of the proposed micromechanics in the dynamic analysis of shell structure. First, the detailed constructional attributes of the proposed trans-scale composite material system are described in detail. Then, according to the nature of the constructional feature, mathematical modelling of each constituent phase or building block’s material properties is established to evaluate the homogenised viscoelastic properties of the proposed composite material system. To highlight the novelty of this study, the viscoelastic characteristics of the modified matrix are developed using the micromechanics method of Mori–Tanaka (MT) in combination with the weak viscoelastic interphase (WI) theory. In the entire micromechanical framework, the CNTs are considered to be randomly oriented. The strength of the material (SOM) approach is used to establish mathematical frameworks for the viscoelastic characteristics of yarns, whereas the unit cell method (UCM) is used to determine the viscoelastic properties of the representative unit cell (RUC). Different numerical results have been obtained by varying the CNT composition, interface conditions, agglomeration, carbon fibre volume percentage, excitation frequency, and temperature. The influences of geometrical parameters like yarn thickness, width, and the gap length to yarn width ratio on the viscoelasticity of such composite material systems are also explored. The current study also addresses the issue of resultant anisotropic viscoelastic properties due to the use of dissimilar yarn thickness. The results of this micromechanical analysis provide valuable insights into the viscoelastic properties of the proposed composite material system and suggest its potential applications in vibration damping. To demonstrate the application of developed novel micromechanics in vibration analysis, as one of the main contributions, comprehensive numerical experiments are conducted on a shell panel. The results show a significant reduction in vibration amplitudes compared to traditional composite materials in the frequency response and transient response analyses. To focus on the aspect of micromechanical behaviour on dynamic response and for the purpose of brevity, only linear strain displacement relationships are considered for dynamic analysis. These insights could inform future research and development in the field of composite materials.

Assessing REALTER simulator: analysis of ocular movements in simulated low-vision conditions with extended reality technology.

Immersive technology, such as extended reality, holds promise as a tool for educating ophthalmologists about the effects of low vision and for enhancing visual rehabilitation protocols. However, immersive simulators have not been evaluated for their ability to induce changes in the oculomotor system, which is crucial for understanding the visual experiences of visually impaired individuals. This study aimed to assess the REALTER (Wearable Egocentric Altered Reality Simulator) system's capacity to induce specific alterations in healthy individuals' oculomotor systems under simulated low-vision conditions. We examined task performance, eye movements, and head movements in healthy participants across various simulated scenarios. Our findings suggest that REALTER can effectively elicit behaviors in healthy individuals resembling those observed in individuals with low vision. Participants with simulated binocular maculopathy demonstrated unstable fixations and a high frequency of wide saccades. Individuals with simulated homonymous hemianopsia showed a tendency to maintain a fixed head position while executing wide saccades to survey their surroundings. Simulation of tubular vision resulted in a significant reduction in saccade amplitudes. REALTER holds promise as both a training tool for ophthalmologists and a research instrument for studying low vision conditions. The simulator has the potential to enhance ophthalmologists' comprehension of the limitations imposed by visual disabilities, thereby facilitating the development of new rehabilitation protocols.

Video game addiction is associated with early stage of inhibitory control problems: An event-related potential study using cued Go/NoGo task.

Video game addiction (VGA) is associated with cognitive problems, particularly deficits in inhibitory control. The present study aimed to investigate behavioural responses and event-related potential associated with specific response inhibition using the cued Go/NoGo task to examine the effects of VGA on brain activity related to response inhibition. Twenty-five individuals addicted to video games (action video games) and 25 matched healthy controls participated in the study. The results showed that the VGA group had significantly more commission error in the NoGo trials and faster reaction time in the Go trials compared with the control group. The event-related potential analyses revealed significant reductions in amplitudes of N2 cue and N2 NoGo in the VGA group. While there was no significant difference between the N2 amplitudes of the Go and NoGo trials in the VGA group, the control group had a larger N2 amplitude in the NoGo trials. These results indicate that VGA subjects have difficulties in the early stages of response inhibition, as well as some level of impairment in proactive cognitive control.

Active vibration control of rotating smart bidirectional FGPTC subjected to internal mechanical shock

This study considers the active vibration control of a sandwich truncated cone, whose intermediate layer is made of bidirectional functionally graded (FG) porous material bonded with integrated piezoelectric actuator and sensor layers on its outer and inner surfaces. The material properties of the bidirectional functionally graded porous truncated cone (FGPTC), with even and uneven porosity distributions along the length and thickness directions, are changed using a power law function. The governing motion equations utilize the two-dimensional (2D) axisymmetric theory of elasticity rather than simple shell theories. The solving of the governing motion equations is accomplished through the utilization of graded finite element and Newmark methods. The study investigates the impact of dimensions, parameters, and porosity types on transient response behavior, including the semi-vertex angle and the ratio of truncated cone length to outer radius. Furthermore, the effects of power index, porosity volume fractions, rotational velocities, and boundary conditions are examined. Active vibration control (AVC) of the piezoelectric FGPTC is achieved by employing a closed-loop control algorithm based on velocity feedback. Several numerical simulations are conducted to evaluate the effectiveness of the proposed active vibration control system in reducing structural vibrations. The results demonstrate significant reductions in vibration amplitudes and improved structural stability achieved through the active control approach.

Estrogen-mediated coupling via gap junctions in the suprachiasmatic nucleus.

The circadian clock orchestrates many physiological and behavioural rhythms in mammals with 24-h periodicity, through a hierarchical organisation, with the central clock located in the suprachiasmatic nucleus (SCN) in the hypothalamus. The circuits of the SCN generate circadian rhythms with precision, relying on intrinsic coupling mechanisms, for example, neurotransmitters like arginine vasopressin (AVP), vasoactive intestinal peptide (VIP), neuronal gamma-aminobutyric acid (GABA) signalling and astrocytes connected by gap junctions composed of connexins (Cx). In female rodents, the presence of estrogen receptors (ERs) in the dorsal SCN suggests an influence of estrogen (E2) on the circuit timekeeping that could regulate circadian rhythm and coupling. To investigate this, we used SCN explants together with hypothalamic neurons and astrocytes. First, we showed that E2 stabilised the circadian amplitude in the SCN when rAVPs (receptor-associated vasopressin peptides) were inhibited. However, the phase delay induced by VIPAC2 (VIP receptors) inhibition remained unaffected by E2. We then showed that E2 exerted its effects in the SCN via ERβ (estrogen receptor beta), resulting in increased expression of Cx36 and Cx43. Notably, specific inhibition of both connexins resulted in a significant reduction in circadian amplitude within the SCN. Remarkably, E2 restored the period with inhibited Cx36 but not with Cx43 inhibition. This implies that the network between astrocytes and neurons, responsible for coupling in the SCN, can be reinforced through E2. In conclusion, these findings provide new insights into how E2 regulates circadian rhythms ex vivo in an ERβ-dependent manner, underscoring its crucial role in fortifying the SCN's rhythm.

Fibrin Glue Acutely Blocks Distal Muscle Contraction after Confirmed Polyethylene Glycol Nerve Fusion: An Animal Study.

Polyethylene glycol (PEG) is a synthetic, biodegradable, and hyperosmotic material promising in the treatment of acute peripheral nerve injuries. Our team set out to investigate the impact of fibrin glue upon PEG fusion in a rat model. Eighteen rats underwent sciatic nerve transection and PEG fusion. Electrophysiologic testing was performed to measure nerve function and distal muscle twitch. Fibrin glue was applied and testing repeated. Due to preliminary findings, fibrin glue was applied to an uncut nerve in five rodents and testing was conducted before and after glue application. Mann-Whitney U tests were used to compare median values between outcome measures. A Shapiro-Wilk test was used to determine normality of data for each comparison, significance set at a P value less than 0.05. PEG fusion was confirmed in 13 nerves with no significant change in amplitude (P = 0.054), latency (P = 0.114), or conduction velocity (P = 0.114). Stimulation of nerves following PEG fusion produced distal muscle contraction in 100% of nerves. Following application of fibrin glue, there was a significant reduction in latency (P = 0.023), amplitude (P < 0.001), and conduction velocity (P = 0.023). Stimulation of the nerve after application of fibrin glue did not produce distal muscle twitch. Five uncut nerves with fibrin glue application blocked distal muscle contraction following stimulation. Our data suggest that fibrin glue alters the nerve's function. The immediate confirmation of PEG fusion via distal muscle twitch is blocked with application fibrin glue in this experimental model. Survival and functional outcome studies are necessary to understand if this has implications on the long-term functional outcomes.

Hybrid Technique for Vibration Control using Synchronized Switch Damping on Inductor Modal Approach and Shape Memory Alloy Integration

Vibration control is a critical aspect of various engineering applications, including automotive and aerospace systems. This research paper presents a novel approach to enhance the performance of the Synchronized Switch Damping on Inductor (SSDI) technique by incorporating Shape Memory Alloys (SMAs). SSDI has proven effective in managing energy dissipation during electronic switching transitions, mitigating voltage spikes and reducing electromagnetic interference. However, the method consumes a substantial amount of energy. In this study, we propose a hybrid approach that combines the benefits of SSDI with the unique properties of SMAs to achieve improved vibration control. The integration of SMAs introduces a semi-passive element to the system, exploiting the inherent properties of these alloys to undergo reversible shape changes in response to external stimuli. By strategically placing SMAs within the vibration-prone components of the system, we aim to harness the mechanical forces generated during shape recovery to counteract and dampen vibrations. This innovative approach aims to capitalize on the efficient energy conversion capabilities of SMAs, thus minimizing the additional energy consumption associated with traditional semi-passive methods. The research involves theoretical modeling and simulation studies to assess the effectiveness of the proposed technique. Preliminary results demonstrate a significant reduction in vibration amplitudes and enhanced damping capabilities, validating the potential of the integrated SSDI-SMA system. The findings of this study not only contribute to advancements in vibration control methodologies but also provide insights into the broader applications of SMA-enhanced semi-passive techniques in improving the overall performance and efficiency of systems.

Analysis of direct and indirect noise in a next-generation aviation gas turbine combustor

A large-eddy simulation (LES) of a next-generation combustor is performed to examine effects of this combustor concepts on direct and indirect combustion noise characteristics. Direct noise is computed considering the unsteady heat release predictions while entropy fluctuations in the downstream part of the combustor are used to estimate indirect noise through the transfer function of the outlet nozzle. A low-order acoustic reconstruction technique, which utilizes the Green’s function of the configuration, is developed to compute the acoustics inside the combustor. Comparisons to experimental results are reported, showing the reasonable accuracy of the LES and combustion noise computations. The direct noise spectrum peaks at frequencies around 3 kHz because of the fast timescales associated with the chemical reactions inside the combustor. In addition, the indirect noise is dominant at low frequencies, i.e., less than 400 Hz, because of the characteristics of the entropy spectrum at the outlet nozzle. Compared to a conventional rich-quench-lean (RQL) combustor configuration, significant differences in the acoustics are observed, and are explained by two specific technological novelties. Firstly, the direct noise spectrum peaks at significantly higher frequencies due to the combustor’s compactness. Secondly, the entropy inhomogeneities downstream of the combustion region are an order of magnitude smaller in amplitude due to the lack of dilution with cold air. This leads to a significant reduction in the indirect noise amplitude at low frequencies, where it is the dominant source of noise. These results suggest opportunities for advanced combustion technologies to achieve substantial reductions in combustion-related noise.

Motor fiber function in spinal muscular atrophy-analysis of conduction velocity distribution.

The motor neuron survival protein, which is deficient in spinal muscular atrophy (SMA), performs numerous cellular functions. Currently, SMA is believed to be a multi-organ disease, including lesion of various structures of the central and peripheral nervous systems. Motor nerve damage, especially in milder SMA types, is controversial. This prompted the conduct of the electrophysiological studies in adults with SMA types 2 and 3 presented in this paper. The study group consisted of 44 adult patients with SMA types 2 and 3. All patients underwent neurological examination with Hammersmith Functional Motor Scale-Expanded (HFMSE) assessment. Standard electrophysiological studies in the ulnar nerve and conduction velocity distribution (CVD) tests were performed in all patients and controls. A prolongation of the distal latency and lowering of the motor potential amplitude with no changes in CVD were found in the whole patient group. There were no dependencies on the number of gene copies. Patients with low HFSME value had slower standard conduction velocity, CVD in upper and median quartiles, and narrower CVD spread; in milder SMA, CVD spread was greater than in controls. The significant reduction in motor response amplitude in SMA seems to be primarily related to motor neuron loss and directly proportional to its severity. The coexisting rearrangement in the peripheral nerve structure is present in SMA, and this could be partially caused by a coexisting demyelinating process. Nerve remodeling mainly affects large fibers and occurs in more severe SMA types with significant disability.

Enhancing pain modulation: the efficacy of synchronous combination of virtual reality and transcutaneous electrical nerve stimulation

IntroductionVirtual reality (VR) and transcutaneous electrical nerve stimulation (TENS) have emerged as effective interventions for pain reduction. However, their standalone applications often yield limited analgesic effects, particularly in certain painful...

Is auditory processing measured by the N100 an endophenotype for psychosis? A family study and a meta-analysis.

The N100, an early auditory event-related potential, has been found to be altered in patients with psychosis. However, it is unclear if the N100 is a psychosis endophenotype that is also altered in the relatives of patients. We conducted a family study using the auditory oddball paradigm to compare the N100 amplitude and latency across 243 patients with psychosis, 86 unaffected relatives, and 194 controls. We then conducted a systematic review and a random-effects meta-analysis pooling our results and 14 previously published family studies. We compared data from a total of 999 patients, 1192 relatives, and 1253 controls in order to investigate the evidence and degree of N100 differences. In our family study, patients showed reduced N100 amplitudes and prolonged N100 latencies compared to controls, but no significant differences were found between unaffected relatives and controls. The meta-analysis revealed a significant reduction of the N100 amplitude and delay of the N100 latency in both patients with psychosis (standardized mean difference [s.m.d.] = -0.48 for N100 amplitude and s.m.d. = 0.43 for N100 latency) and their relatives (s.m.d. = - 0.19 for N100 amplitude and s.m.d. = 0.33 for N100 latency). However, only the N100 latency changes in relatives remained significant when excluding studies with affected relatives. N100 changes, especially prolonged N100 latencies, are present in both patients with psychosis and their relatives, making the N100 a promising endophenotype for psychosis. Such changes in the N100 may reflect changes in early auditory processing underlying the etiology of psychosis.

Monitoring the electrophysiological effects of hydroquinidine non-invasively in patients with Brugada syndrome

Abstract Background Quinidine and it’s derivative hydroquinidine are the only drugs shown to reduce arrhythmic events in patients with Brugada syndrome (BrS). There is currently no standardised approach to monitoring the effect of pharmacotherapy in BrS to guide dosing and evaluate an individual’s response to therapy. Purpose To investigate if the electrophysiological effects of Hydroquinidine can be detected on non-invasive testing and identify parameters that may be used to study a non-invasive strategy for monitoring pharmacotherapy in BrS. Methods Patients with a diagnosis of BrS underwent multimodality non-invasive assessment with electrocardiogram (ECG), signal averaged ECG, 24 hour 12-lead Holter monitor and electrocardiographic imaging (ECGi – a method of non-invasive electroanatomical mapping), at baseline and "on treatment" with hydroquinidine (300mg BD) therapy. A medication survey was used to recorded adverse drug reactions and serum hydroquinidine levels were determined using liquid chromatography mass spectrometry. Results Twelve patients with BrS (11 male, mean age 47.6±10.9 years) with spontaneous type 1 BrS pattern or drug inducible type 1 BrS pattern and resuscitated cardiac arrest participated in the study. The mean Shanghai score was 4.6±1.4 and two patients had disease-causing SCN5A variants. During hydroquinidine therapy, there was a significant increase in QRS duration (110.7msec vs 117.8msec, p=0.004) and in mean activation time in the area of late activation in the right ventricular outflow tract (RVOT, 90.9ms to 97.7ms, p=0.020). In nine (75%) patients, the area of late activation (defined as &amp;gt;80ms after initial activation) in the RVOT also increased with hydroquinidine. Repolarisation parameters were also affected by hydroquinidine with an increase in QT interval corrected for heart rate (369.5msec vs 434.8msec, p&amp;lt;0.0001) and T-wave width (232.8msec to 271.2msec p=0.003) and a significant reduction in T-wave amplitude (0.4mV to 0.2mV p=0.001) on treatment. The reduction in T-wave amplitude precluded computation of repolarisation time in the RVOT by ECGi on treatment. No difference in the burden of type 1 BrS ECG pattern over 24 hours was seen on 12-lead Holter monitor between baseline and on treatment assessment. No significant difference in serum hydroquinidine level was detected between those who experienced side effects and those who did not (2.9µmol vs 3.1µmol, p=0.790). Conclusion Hydroquinidine affects both ventricular activation and repolarisation in patients with BrS and these effects can be detected non-invasively. Further work is required to determine clinical significance of these observed effects and investigate the feasibility of non-invasive monitoring strategy of pharmacotherapy in BrS.ECGi activation maps

The effects of carvacrol and p-cymene on Aβ1-42 -induced long-term potentiation deficit in male rats.

Alzheimer's disease (AD) is the most common type of dementia in which oxidative stress plays an important role. In this disease, learning and memory and the cellular mechanism associated with it, long-term potentiation (LTP), are impaired. Considering the beneficial effects of carvacrol (CAR) and p-cymene against AD, their effect was assessed on in vivo hippocampal LTP in the perforant pathway (PP)-dentate gyrus (DG) pathway in an Aβ1-42 -induced rat model of AD. Male Wistar rats were randomly assigned to five groups: sham: intracerebroventricular (ICV) injection of phosphate-buffered saline, Aβ: ICV Aβ1-42 injections, Aβ + CAR (50 mg/kg), Aβ + p-cymene (50 mg/kg), and Aβ + CAR + p-cymene. Administration of CAR and p-cymene was done by gavage daily 4 weeks before and 4 weeks after the Aβ injection. The population spike (PS) amplitude and field excitatory postsynaptic potentials (fEPSP) slope were determined in DG against the applied stimulation to the PP. Aβ-treated rats exhibited impaired LTP induction in the PP-DG synapses, resulting in significant reduction in both fEPSP slope and PS amplitude compared to the sham animals. Aβ-treated rats consumed either CAR or p-cymene separately (but not their combination), and showed an enhancement in fEPSP slope and PS amplitude of the DG granular cells. These data indicate that CAR or p-cymene can ameliorate Aβ-associated changes in synaptic plasticity. Surprisingly, the combination of CAR and p-cymene did not yield the same effect, suggesting a potential interaction between the two substances.

P300 event-related potentials in people with epilepsy: clinico-neurophysiologic study

BackgroundThere is increasing evidence that prolonged or recurrent seizures can cause or exacerbate cognitive impairment (CI) in memory, attention, orientation, and visuospatial and abstraction disabilities, all of which can jeopardize educational progress and achievement throughout life. The objectives of our study are to assess the cognitive functions in people with epilepsy (PwE) using P300 event-related potentials (ERPs), and correlate each P300 components with six explanatory variables (epilepsy type, seizure type, NHS3 score- seizure severity, disease duration, age at first seizure, and the number of anticonvulsant medications).MethodsOne hundred and two PwE [52 with focal epilepsy and 50 with generalized epilepsy, as classified by the International League Against Epilepsy in 2017]. They underwent electroencephalography (EEG) and P300. The Montreal Cognitive Assessment (MoCA) scale was used to assess baseline cognitive functions.ResultsEpileptic patients showed significant latency prolongation and amplitude reduction of P300 as compared to non-epileptic population. Longer P300 latency and lower amplitude were seen in patients with abnormal EEG records. P300 latency was longer in patients using poly-therapy. P300 components correlated well with age at presentation and disease duration but not with NHS3. According to epilepsy type, 50.98% of PwE had focal epilepsy and 49.02% had generalized epilepsy, 85.29% of them had abnormal EEG recording. Considering seizure type, 47.06% had a generalized tonic–clonic seizure, 38.24% had a focal to bilateral tonic–clonic seizure, 20.59% had a myoclonic seizure, 12.75% had a focal with impaired awareness seizure, 3.92% had a focal aware seizure, and 2.94% had an absence seizure. Seventy-seven PwE had one type of seizure, while 25 had more than one type of seizure. The NHS3 score was higher in those with a single seizure type than in those with multiple seizure types.ConclusionAll seizure types had an abnormal P300 component, indicating cognitive function deficits. P300 may be a promising objective method for assessing cognitive function in PwE. The number of antiepileptic drugs used, the presence of EEG abnormalities, the age at presentation, and the duration of the disease are the factors that best correlate with cognitive impairment (CI).

Description of a Nonhuman Primate Model of Retinal Ischemia/Reperfusion Injury.

To establish an inducible model of retinal ischemia/reperfusion injury (RI/RI) in nonhuman primates (NHPs) to improve our understanding of the disease conditions and evaluate treatment interventions in humans. We cannulated the right eye of rhesus macaques with a needle attached to a normal saline solution reservoir at up to 1.9 m above the eye level that resulted in high intraocular pressure of over 100 mm Hg for 90 minutes. Retinal morphology and function were monitored before and after RI/RI over two months by fundus photography, optical coherence tomography, electroretinography, and visual evoked potential. Terminal experiments involved immunostaining for retinal ganglion cell marker Brn3a, glial fibrillary acidic protein, and quantitative polymerase chain reaction to assess retinal inflammatory biomarkers. We observed significant and progressive declines in retinal and retinal nerve fiber layer thickness in the affected eye after RI/RI. We noted significant reductions in amplitudes of electroretinography a-wave, b-wave, and visual evoked potential N2-P2, with minimal recovery at 63 days after injury. Terminal experiments conducted two months after injury revealed ∼73% loss of retinal ganglion cells and a fivefold increase in glial fibrillary acid protein immunofluorescence intensity compared to the uninjured eyes. We observed marked increases in tumor necrosis factor-alpha, interferon-gamma, interleukin-1beta, and inducible nitric oxide synthase in the injured retinas. The results demonstrated that the pathophysiology observed in the NHP model of RI/RI is comparable to that of human diseases and suggest that the NHP model may serve as a valuable tool for translating interventions into viable treatment approaches. The model serves as a useful platform to study potential interventions and treatments for RI/RI or blinding retinal diseases.

Anodal transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex improves attentional control in chronically stressed adults.

Chronic stress is a long-term condition that negatively affects cognitive ability and mental health. Individuals who experience chronic stress show poor attentional control. Transcranial direct current stimulation (tDCS) to the dorsolateral prefrontal cortex (DLPFC) modulates executive function domains. Therefore, it is beneficial to investigate whether tDCS of the DLPFC could improve attentional control and relieve stress in chronically stressed individuals. We assess the event-related potentials (ERPs) associated with attentional control in individuals with chronic stress after the tDCS intervention. Forty individuals were randomly assigned to either the anodal tDCS group, which received 5 sessions of the 20 min tDCS over the DLPFC (2 mA; n = 20), or the sham tDCS (n = 20). Participants' stress levels, anxiety, depressive symptoms, and state affects were assessed and compared before and after the intervention. The ERP was collected through electroencephalography (EEG) technology during an attentional network test. After the anodal tDCS, we found a significant decrease in the perceived stress scale (PSS) scores (from an average score of 35.05 to 27.75), p = 0.01 as well as the State-Trait Anxiety Inventory (STAI) scores, p = 0.002. Better performance in the attentional network test, a significant reduction in the N2 amplitudes, and an enhancement in the P3 amplitudes (both cues and targets) were also found in the anodal tDCS group. Our study findings suggest that tDCS to the left DLPFC could effectively relieve chronic stress, potentially reflected by increased attentional control.

EFFECT OF QUENCHING ON THE DYNAMIC MECHANICAL PROPERTIES OF POLYCRYSTALLINE VANADIUM

The effect of quenching at high temperatures on the regularities of changes of the logarithmic decrement of the torsional oscillations damping and the dynamic shear modulus in the 10-5-10-3 interval of strain amplitude in polycrystalline vanadium has been studied. The critical values of the strain amplitude, at which the dislocations segments begin to breakaway from the weak and strong pinning centers have been determined. After short annealing (20 min.) at fixed tempertures of 700 and 900° C and subsequent quenching at room temperture a decrease of impurity concentration in Cottrell atmosphere around the dislocations is achieved. These changes led to a significant reduction of the critical strain amplitude of dislocations blocking and the dynamic shear modulus, and a strong increase in the intensity of energy absorption in a wide range of oscillations amplitudes. The concentration changes of the Cottrell atmosphere around the dislocations led to the formation of several&nbsp; values of elastic limits. The obtained results reveal the possibilities of changing the mobility of the dislocation structure by quenching from high temperatures, which is the basis for controlling of the mechanical properties of vanadium.

Defect of the Endogenous Inhibitory Pain System in Idiopathic Restless Legs Syndrome: A Laser Evoked Potentials Study.

Restless legs syndrome (RLS) is a complex sensorimotor disorder. Symptoms worsen toward evening and at rest and are temporarily relieved by movement. Symptoms are perceived as painful in up to 45% of cases, and nociception system may be involved. To assess the descending diffuse noxious inhibitory control in RLS patients. Twenty-one RLS patients and twenty age and sex-matched healthy controls (HC) underwent a conditioned pain modulation protocol. Cutaneous heat stimuli were delivered via laser evoked potentials (LEPs) on the dorsum of the right hand (UL) and foot (LL). N2 and P2 latencies, N2/P2 amplitude and pain ratings (NRS) were recorded before (baseline), during, and after a heterotopic noxious conditioning stimulation (HNCS) application. The baseline/HNCS ratio was calculated for both UL and LL. N2 and P2 latencies did not vary between groups at each condition and limbs. Both groups showed a physiological N2/P2 amplitude and NRS reduction during the HNCS condition in UL and LL in comparison to baseline and post conditions (all, P < 0.003). Between-groups comparisons revealed a significant lower amplitude reduction in RLS at the N2/P2 amplitude during the HNCS condition only for LL (RLS, 13.6 μV; HC, 10.1 μV; P = 0.004). Such result was confirmed by the significant difference at the ratio (RLS, 69%, HC, 52.5%; P = 0.038). The lower physiological reduction during the HNCS condition at LL in RLS patients suggests a defect in the endogenous inhibitory pain system. Further studies should clarify the causal link of this finding, also investigating the circadian modulation of this paradigm. © 2023 International Parkinson and Movement Disorder Society.