Frequency Fluctuations Research Articles

Abnormal amplitude of low-frequency fluctuations associated with sleep efficiency in major depressive disorder

BackgroundSleep disturbance is one of the most frequent somatic symptoms in major depressive disorder (MDD), but the neural mechanisms behind it are not well understood. Sleep efficiency (SE) is a good indicator of early awakening and difficulty falling asleep in MDD patients. Our study aimed to investigate the relationship between sleep efficiency and brain function in MDD patients. MethodsWe recruited 131 MDD patients from the Fourth People's Hospital in Hefei, and 71 well-matched healthy controls who were enrolled from the community. All subjects underwent resting-state functional MRI. Brain function was measured using the fractional amplitude of low-frequency fluctuation (fALFF), sleep efficiency was objectively measured by polysomnography (PSG), and clinical scales were used to evaluate depressive symptoms and sleep status. Multivariate regression analysis was performed to assess the relationship between the amplitude of the low frequency fluctuation fraction and sleep efficiency. ResultThree brain regions with relevance to sleep efficiency in MDD patients were found: inferior occipital gyrus (Number of voxels = 25, peak MNI coordinate x/y/z = −42/-81/-6, Peak intensity = 4.3148), middle occipital gyrus (Number of voxels = 55, peak MNI coordinate x/y/z = −30/-78/18, Peak intensity = 5.111), and postcentral gyrus (Number of voxels = 26, peak MNI coordinate x/y/z = −27/-33/60, Peak intensity = 4.1263). But there was no significant relationship between fALFF and SE in the healthy controls. ConclusionThe reduced sleep efficiency in MDD may be related to their lower neural activity in the inferior occipital gyrus, middle occipital gyrus, and postcentral gyrus. The findings may provide a potential neuroimaging basis for the clinical intervention in patients with major depressive disorder with sleep disturbances.

Fractional-Order Load Frequency Control of an Interconnected Power System with a Hydrogen Energy-Storage Unit

Modern power systems are confronted with widespread concern on the frequency stability issue due to the widespread integration of randomly fluctuating renewable resources. To address the above concern, this work introduces a load-frequency-control (LFC) scheme based on a parameter tuning strategy for fractional-order proportional–integral–derivative (FOPID) controller. Firstly, a two-area interconnected power system (IPS) model, including thermal, hydro, solar, wind, and gas power generator and a hydrogen-based energy-storage unit, is established. Then, a FOPID controller is designed for this IPS model, and an improved gradient-based optimizer (IGBO) is developed to adaptively regulate the parameters of the FOPID controllers. Finally, the effectiveness of the offered LFC scheme is tested through load disturbance and renewable energy fluctuations test scenarios and provides a comparison and robustness analysis among different schemes. The test results validated that the offered LFC scheme can effectively suppress the frequency fluctuations of the IPS and has excellent robustness.

Accessibility of Opioid Treatment Programs Based on Conventional vs Perceived Travel Time Measures

Transportation barriers have long been associated with poorer health outcomes; this burden is especially acute for individuals with opioid use disorder (OUD), a chronic disease often associated with low socioeconomic status. Conventional travel time analyses may not fully account for experiential components of travel, thereby understating the true travel burden and overstating treatment accessibility to opioid treatment programs (OTPs). To develop a metric of feels-like accessibility for those using public transit to access OTPs that accounts for the realistic travel burden on individuals with OUD. This cross-sectional study integrated high-resolution transit schedules and operating hours of OTPs to measure feels-like accessibility. Feels-like accessibility considers the differential outcomes of out-of-vehicle travel components and more realistically reflects individuals' transportation burden than conventional accessibility measures. Gini indices and spatial regression models were used to investigate inequities in accessibility. Geocoded data for residential addresses of 1018 overdose fatalities in Connecticut in 2019 were used as a proxy for the treatment needs of individuals with OUD. Data were analyzed between May and August 2023. Conventional and feels-like accessibility scores. Fluctuations in public transit frequencies over the course of the day and the limited operating hours of the OTPs. Of the 1018 individuals in the study, the mean (SD) age at death was 43.7 (12.6) years, 784 individuals (77%) were men, 111 (11%) were African American, and 889 (87%) were White, with other racial and ethnic categories including 18 individuals (2%). A total of 264 individuals in the sample (26%) could not access an OTP within 180 minutes. For those who could access these facilities, the average 1-way travel time was 45.6 minutes, with individuals spending approximately 70% of their trip duration on out-of-vehicle travel components. The conventional accessibility metric underestimates individuals' travel burden to OTPs as well as the inequity in accessibility compared with the feels-like accessibility metric. For example, the median (range) conventional accessibility score, defined as the number of OTPs within 120 minutes of transit travel time, was 5.0 (0.0-17.0); the median (range) feels-like accessibility score, defined as the number of OTPs within 120 minutes of transit travel time weighted to account for in- and out-of-vehicle segments, was 1.0 (0.0-10.0). There is a considerable temporal variation in travel time and accessibility depending on the departure times. In this cross-sectional study of travel burdens, the calculated feels-like accessibility scores, which consider the differential outcomes of out-of-vehicle travel components (eg, walking and waiting), could better and more realistically reflect passengers' transportation burden. Policy recommendations derived from the conventional accessibility metric could be misleading, and decision-makers should use feels-like accessibility metrics that adequately capture individuals' travel burdens. In the context of access to OTPs, the findings from this study suggest that opening new OTP sites to address gaps in access due to distance to services or extending hours of operation at existing sites may ameliorate the travel burden for individuals.

Life Cycle Assessment of Energy Storage Technologies for New Power Systems under Dual‐Carbon Target: A Review

Aiming at the grid security problem such as grid frequency, voltage, and power quality fluctuation caused by the large‐scale grid‐connected intermittent new energy, this article investigates the life cycle assessment of energy storage technologies based on the technical characteristics and performance indicators. First, the new power system under dual‐carbon target is reviewed, which is compared with the traditional power system from the generation side, grid side, and user side. Based on the power characteristics of the new power system, the energy storage mechanism and energy storage characteristics of mechanical energy storage, electrochemical energy storage, chemical energy storage, electromagnetic energy storage, and thermal energy storage are described. Then, compared with the existing research strategies, a comprehensive life cycle assessment of energy storage technologies is carried out from four dimensions: technical performance, economic cost, safety assessment, and environmental impact. Moreover, the suitable scenarios and application functions of various energy storage technologies on the power generation side, grid side, and user side are compared and analyzed from the working principle, key technologies, advantages and disadvantages, and technical difficulties of energy storage technologies. Finally, combined with the energy storage technologies in the electricity market, four profit models are analyzed.

Neuropathological characteristics of abnormal white matter functional signaling in adolescents with major depression.

Major depression disorder (MDD) constitutes a significant mental health concern. Epidemiological surveys indicate that the lifetime prevalence of depression in adolescents is much higher than that in adults, with a corresponding increased risk of suicide. In studying brain dysfunction associated with MDD in adole-scents, research on brain white matter (WM) is sparse. Some researchers even mistakenly regard the signals generated by the WM as noise points. In fact, studies have shown that WM exhibits similar blood oxygen level-dependent signal fluctuations. The alterations in WM signals and their relationship with disease severity in adolescents with MDD remain unclear. To explore potential abnormalities in WM functional signals in adolescents with MDD. This study involved 48 adolescent patients with MDD and 31 healthy controls (HC). All participants were assessed using the Patient Health Questionnaire-9 Scale and the mini international neuropsychiatric interview (MINI) suicide inventory. In addition, a Siemens Skyra 3.0T magnetic resonance scanner was used to obtain the subjects' image data. The DPABI software was utilized to calculate the WM signal of the fractional amplitude of low frequency fluctuations (fALFF) and regional homogeneity, followed by a two-sample t-test between the MDD and HC groups. Independent component analysis (ICA) was also used to evaluate the WM functional signal. Pearson's correlation was performed to assess the relationship between statistical test results and clinical scales. Compared to HC, individuals with MDD demonstrated a decrease in the fALFF of WM in the corpus callosum body, left posterior limb of the internal capsule, right superior corona radiata, and bilateral posterior corona radiata [P < 0.001, family-wise error (FWE) voxel correction]. The regional homogeneity of WM increased in the right posterior limb of internal capsule and left superior corona radiata, and decreased in the left superior longitudinal fasciculus (P < 0.001, FWE voxel correction). The ICA results of WM overlapped with those of regional homo-geneity. The fALFF of WM signal in the left posterior limb of the internal capsule was negatively correlated with the MINI suicide scale (P = 0.026, r = -0.32), and the right posterior corona radiata was also negatively correlated with the MINI suicide scale (P = 0.047, r = -0.288). Adolescents with MDD involves changes in WM functional signals, and these differences in brain regions may increase the risk of suicide.

A Fast-Response Method for Determining the Amplitude of a Signal in Microprocessor Automation and Control Systems with Frequency Fluctuations

In microprocessor automation and control systems, the amplitude (effective) values of the fundamental harmonic of the input signals are widely used as information parameters of the controlled quantities. They are most often determined by samples of one or a pair of orthogonal components of the signal, for the formation of which digital Fourier filters and their modifications are mainly used. At the rated frequency in the power system, these filters ensure reliable reception of the signal amplitude without additional error. If the frequency deviates from the rated one, the number of samples per signal period is not an integer and the discretization becomes asynchronous. As a result, a corresponding error appears in the amplitude of the signal, and its change becomes oscillating. With minor frequency fluctuations in the normal mode, the amplitude error is insignificant. However, in abnormal situations, the frequency can have significant variations. At the same time, in critical situations, failure of automation and control systems, as well as incorrect operation of their functional algorithms, cannot be excluded. Known methods for determining the amplitude of a signal with frequency fluctuations provide a solution to the existing problem, but they are characterized by a slow response. The proposed high-response method for determining the amplitude during frequency fluctuations is focused on using as initial information samples of instantaneous values of the cosine orthogonal component of the signal, which are formed using an appropriate digital Fourier filter. Based on these samples, the dynamic cosine and sine of the angle of one sample are calculated, the use of which in calculating the amplitude ensures its independence from frequency. Processing of the received amplitude with an amplifying element with a nonlinear coefficient makes it possible to achieve acceptable performance. The effectiveness of the proposed solution was evaluated by a computational experiment using a digital model implemented in the MATLAB-Simulink dynamic modeling environment. In this case, both sinusoidal input signals and complex ones, close to the real secondary signals of measuring transformers, were used as test actions. As a result of the research, it was found that the proposed method for determining the amplitude during frequency fluctuations has a performance at the level of a quarter of the period and provides effective elimination of frequency error both in load modes and in damage modes.

Dielectric, structural, and optical studies of l-histidine glutarate monohydrate (LHGMH): an organic crystal

This study used the slow evaporation of solvent technique to create L-histidine glutarate monohydrate (LHGMH) crystals. The LHGMH crystals were characterized by single-crystal XRD, Raman, UV-Visible, second harmonic generation, and dielectric tests. The temperature coefficient of solubility of the sample is positive. The LHGMH crystallized as an orthorhombic structure with the space group P212121. Raman spectroscopy described the sample’s molecular vibrations. The UV-Vis spectra demonstrated the optical transparency of the LHGMH. The bandgap of LHGMH is 5.30 eV. The frequency and temperature-dependent fluctuations of the dielectric value, together with the loss factor, were investigated in the dielectric test.

Providing a Control System for Charging Electric Vehicles Using ANFIS

Frequency control, especially when incorporating distributed generation units such as wind and solar power plants, is crucial for maintaining grid stability. To address this issue, a study proposes a method for controlling the connection status of electric vehicles (EVs) to prevent frequency fluctuations. The method utilizes an adaptive neural-fuzzy inference system (ANFIS) and a whale optimization algorithm to regulate the charging or discharging of EV batteries based on frequency fluctuations. The objective is to minimize and adjust the frequency fluctuations to zero. The proposed method is evaluated using a real microgrid composed of a wind power plant, a solar power plant, a diesel generator, a large household load, an industrial load, and 711 electric vehicles. The ANFIS system serves as the primary controller, taking inputs such as electric vehicle and battery status and generating outputs that determine the charging or discharging of the electric vehicles. Several investigations are conducted to assess the effectiveness of this model, and the results obtained are compared with the normal state where electric vehicles only consume power. By implementing this method, it is expected that the connection status of electric vehicles can be optimized to help stabilize the grid and minimize frequency fluctuations caused by the integration of distributed renewable energy sources. This study highlights the importance of automatic frequency control in smart grids and offers a potential solution using ANFIS and the whale optimization algorithm.

Functional Abnormality of the Reward System in Depressed Adolescents and Young Adults with and without Suicidal Behavior.

To identify local and functional connectivity abnormalities in the brain's reward network in depressed adolescents and young adults with and without suicidal behavior. Magnetic resonance imaging data were obtained from 41 major depressive disorder (MDD) patients with suicidal behavior (sMDD, males/females: 12/29), 44 MDD patients without suicidal behavior (nMDD, males/females: 13/32), and 52 healthy controls (HCs, males/females: 17/35). The Young Mania Scale, Hamilton Depression Scale, Columbia Suicide Scale, and Scale for Suicide Ideation were used to evaluate emotional state and suicidal ideation and behaviors. The amplitude of low frequency fluctuations (ALFF), regional homogeneity (ReHo) and functional connectivity of 11 regions of interest (ROIs) in the reward network were determined. ALFF values in the vmPFC of the nMDD group were significantly lower than those in the HC group (p = 0.031). The ReHo values of the nMDD group were lower in the lVS but higher in the vmPFC than those of the HC group (P = 0.018 and 0.025, respectively). Functional connectivity of the AC with the vmPFC, lVS, rVS, and vmPFC was increased in the sMDD group compared with that in the nMDD group (P = 0.038, 0.034, 0.006, respectively). Local and functional connectivity abnormalities in the reward network were found in the MDD groups. However, increased functional connectivity was found in only the sMDD group.

Numerical Investigation on the Aerodynamic and Aeroacoustic Characteristics in New Energy Vehicle Cooling Fan with Shroud

The cooling fan is one of the important noise sources for new energy vehicles, and the research on its aerodynamic and aeroacoustic characteristics is of great help to improve the noise, vibration and harshness performance of new energy vehicles. However, most of these studies focus on the impeller, and little consideration has been given to the study of the shroud. Based on the coupling calculation method of large eddy simulation and the Ffowcs-Williams and Hawkings acoustics model, the aerodynamic and aeroacoustic characteristics in a cooling fan with the shroud are investigated at flow rates from 0.623 kg/s to 1.019 kg/s (where 0.865 kg/s is the flow rate corresponding to the best efficiency point). The accuracy of numerical simulation results is verified by the grid independence verification and the comparison of experimental data. Research shows that several large-scale vortex structures are observed in the clearance between the impeller and the shroud. The maximum peak-to-peak values of pressure fluctuation at different flow rates occur in the intermediate section or outlet section of the shroud. Although the shroud contributes relatively less to the far field noise, its different distribution may change the position of the maximum sound pressure level. The dominant frequency of pressure fluctuation equals the blade passage frequency (BPF) and the maximum SPL is around the BPF, both of which are independent of flow rates. The maximum SPL and the amplitude of the dominant frequency decrease as the flow rate increases.

Integrated control strategy of BESS in primary frequency modulation considering SOC recovery

AbstractThis paper proposes a comprehensive control strategy for a battery energy storage system (BESS) participating in primary frequency modulation (FM) while considering the state of charge (SOC) recovery. On the one hand, when the frequency fluctuations are outside the dead zone of the FM, variable coefficient virtual sag control and variable coefficient virtual inertia control are coordinated for more accurate primary FM. Also, an assisted FM strategy is proposed, where the temporal alignment of assisted FM is determined by the regional segmentation of the frequency deviation and SOC, and it enables the BESS to recover SOC concurrently during its involvement in primary FM. On the other hand, when the frequency fluctuations are inside the dead zone of the FM, typical S‐type functions are deployed to dynamically establish the mutual constraints relationships of SOC recovery demand coefficient and frequency deviation. Subsequently, the recovery control coefficients are derived, and accordingly, a SOC recovery strategy is proposed. Finally, simulation results verify the efficacy of the proposed control strategy in the grid primary FM system and demonstrate that the strategy expedites the SOC recovery and concurrently diminishes the conventional unit output.

Numerical analysis of flow instability with vortex cavitation in venturi tube

The swirling flow with cavitation can cause pressure pulsations in a draft tube of a hydro turbine at off-design operating conditions. Especially at the full load condition, the cavitation volume may fluctuate greatly, causing pressure pulsations with flow rate fluctuations known as cavitation surge throughout the hydraulic system. The cases that predicted the phenomenon qualitatively using the CFD analysis have been reported previously, whereas the methods to predict the cavitation volume and the fluctuation frequency in the cavitation surge condition quantitatively have not yet been established. Therefore, in this study, unsteady CFD analysis was conducted for the experimental apparatus that simulates the flow in the draft tube downstream of a runner using the stationary guide vane and the venturi tube. In CFD analysis, the influence of the turbulence models by using LES and SST and the influence of the number of meshes in LES simulation were investigated. It was founded that LES simulation captured the vortex generation finely and improved the prediction accuracy of the cavitation volume than SST simulation. On the other hand, it was founded that too fine mesh has a small effect on the prediction accuracy of the cavitation volume, although the resolution of the vortex is improved.

Effects of Nonzero-frequency Fluctuations on Turbulence Spectral Observations

In situ observations of turbulence spectra in space plasmas are usually interpreted as wavenumber spectra, assuming that the fluctuation frequency is negligible in the plasma flow frame. We explore the effects of nonzero frequency in the plasma flow frame on turbulence spectral observations. The finite frequency can be caused by either propagating waves or nonlinear broadening of nonpropagating structures. We show that the observed frequency spectrum can be modified by the nonzero frequency of turbulent fluctuations in several ways. Specifically, (i) frequency broadening results in a minor modification to the observed spectrum, primarily acting as a smoothing kernel of the spectrum near the spectral break, while the asymptotic spectral index remains unchanged; (ii) wave propagation can affect the observed spectral index for anisotropic turbulence. The effect is significant at low frequencies and weaker at high frequencies, leading to a “concave” shape of the observed perpendicular spectrum; (iii) the Doppler shift for forward- and backward-propagating Elsasser modes can result in a nonzero cross helicity for critical-balanced turbulence since the effect of the Doppler shift favors outward-propagating waves systematically, resulting in an observed imbalance. These results may have important implications for the interpretation of solar wind flows observed by Parker Solar Probe.

Flexural isostatic response of continental-scale deltas to climatically driven sea level changes

Abstract. The interplay between climate-forced sea level change, erosional and depositional processes, and flexural isostasy in deep time on passive margin deltas remains poorly understood. We performed a series of conceptual simulations to investigate flexural isostatic responses to high-frequency fluctuations in water and sediment load associated with climatically driven sea level changes. We model a large drainage basin that discharges to a continental margin and produces a large deltaic depocenter, then prescribe synthetic and climatic-driven sea level curves of different frequencies to assess flexural response. Results show that flexural isostatic responses are bidirectional over 100–1000 kyr timescales and are in sync with the magnitude, frequency, and direction of sea level fluctuations and that isostatic adjustments play an important role in driving along-strike and cross-shelf river mouth migration and sediment accumulation. Our findings demonstrate that climate-forced sea level changes produce a feedback mechanism that results in self-sustaining creation of accommodation into which sediment is deposited and plays a major role in delta morphology and stratigraphic architecture.

Systematic investigation of cerebellar functional alterations and their association with surgical outcomes in patients with degenerative cervical myelopathy: a resting-state fMRI study.

The aim of this study was to systematically investigate the changes in cerebellar neural activity and cerebellar-cortical functional connectivity (FC) in patients with degenerative cervical myelopathy (DCM) using resting-state functional magnetic resonance imaging (fMRI). In this study, we collected clinical data and resting-state fMRI data from 54 DCM patients and 50 healthy controls (HCs). We analyzed voxel-wise regional fMRI metrics, including amplitude of low frequency fluctuation(ALFF), fractional ALFF, regional homogeneity, functional connectivity density, and voxel-mirrored homotopic connectivity. In analysis 1, we examined the differences in regional fMRI metrics within the cerebellum between the DCM patient group and the healthy control group, as well as their correlation with preoperative neurological status and prognosis. In analysis 2, we investigated cerebellar-cortical functional connectivity differences between the two groups and their correlation with preoperative neurological status and prognosis. Lastly, in analysis 3, we explored the internetwork connectivity between the 'cerebellar-SMN' (sensorimotornetwork) system, examined the between-group differences, and investigated its correlation with preoperative neurological status and prognosis. (1) Relative to HCs, DCM patients exhibited functional alterations in wide-spread cerebellar regions; (2) DCM patients exhibited altered cerebellar-cortical FC which was associated with the preoperative neurological status and prognosis; (3) DCM patients exhibited altered internetwork connectivity between 'cerebellar-SMN' system which was associated with duration of symptom. Wide-spread cerebellar functional alterations occur in DCM pathogenesis and the deficits in cerebellar-SMN functional connectivity may be beneficial in future studies for predicting surgical outcomes in patients with DCM.

Control strategy and research on energy storage unit participation in power system frequency regulation based on VSG technology

When large-scale photovoltaic power plants are integrated into the grid, it will cause the grid-connected capacity to gradually expand, causing greater harm to the safe and stable operation of the power system, which will affect the FM characteristics of the power system. This requires the PV power plant to actively participate in power system frequency control. Through the PV virtual synchronous generator frequency control technology, coupled with the virtual synchronous PV power plant modeling, the PV new energy units can have the same frequency control characteristics as synchronous generator sets. In the virtual synchronous technology, due to the existence of damping windings, electromagnetic damping will be generated, and it is also due to virtual damping that the virtual synchronous technology has the ability to damp power oscillations. It is also because of the excellent virtual inertia and damping characteristics of the virtual synchronous generator in the grid that this FM technology helps to regulate the frequency fluctuations of the new energy grid, meet the requirements of the power system to maintain stable operation, and then realize the large-scale PV grid connection.

Investigation on the influence of seal clearance leakage on the rotating stall characteristics for a centrifugal pump

The occurrence and development of centrifugal pump rotating stall is closely related to disturbance in the incoming flow. The seal clearance leakage is an inherent disturbance in the impeller incoming flow of centrifugal pumps. In order to investigate the seal clearance leakage influence on the rotating stall characteristics, the flow field numerical simulation of a centrifugal pump under rotating stall flow conditions with and without seal clearance are carried out. It is found that under the 0.4Q0 rotating stall condition with seal clearance leakage, the “λ” special shaped high-velocity region distribution along the blade leading edges are strengthened, which lead to larger scale of stall vortices. And the periodicity of the separation vortex evolution is more obvious under the condition with leakage. For a specific stall vortex development process, at the initial format stage, there is a notable disturbance characteristic of medium frequencies band that of 2–3 times the rotation frequency in the pressure fluctuation near the blade leading edges, which is significantly different from that under the condition without leakage. The vorticity analysis shows that this disturbance is closely related to the leakage induced vortices. Affected by the seal clearance leakage disturbance, the stall rotating propagation frequency is reduced from 0.143 times the impeller rotational frequency to 0.103 times. Meanwhile, the fluctuation intensity in the impeller channels is greatly enhanced. Therefore, by judging the special fluctuation frequencies, regularity, and intensity trend in the monitoring signal, it can not only be used to guide the safe operation of centrifugal pumps under off-design conditions but also serve as the basis for judging the wear of the seal, which has important practical significance.

Health Behavior Assessment and Rehabilitation of Vestibular Migraine Patients: Interventions through Magnetic Resonance Imaging (MRI)

Objectives: Vestibular Migraine (VM) is a common neurological syndrome where the patient gets recurrent episodes of severe migraine along with vertigo, dizziness and nausea, often diagnosed through magnetic resonance imaging (MRI). This study examines efficiency of an MRI induced vestibular rehabilitation (VR) program in treating patients with VM. Methods: A total of 14 VM patients, including 8 females and 6 males, with an average age of 43.85 years, participated in this study. Clinical evaluations scales such as the Dizziness Handicap Inventory (DHI), Hamilton Anxiety Scale (HAMA), SF36 domains and Hamilton Depression Scale (HAMD) were carried out both at the beginning and end of VR programmes. Results:DHI and HAMA ratings post-VR was significantly decreased (p=0.031 and p=0.021 respectively). In the SF36 domains, role-emotional and role-physical scores increased (p= 0.05). After VR, the left posterior cerebellum's amplitude of low frequency fluctuation (ALFF) values—which measured brain activity— increased (p &lt;0.001), suggesting enhanced neural function. Between DHI scores and ALFF values, there was a significant negative association (r=-0.612, p&lt;0.05). Conclusions: The study stresses the value of VR therapy in treating VM symptoms and improving patient outcomes through improved health behavior.

Dynamic Changes in Local Brain Connectivity and Activity: A Longitudinal Study in Adolescent Anorexia Nervosa

BackgroundResting-state functional connectivity analysis has been used to study disruptions in neural circuitries underlying eating disorder symptoms. Research has shown resting-state functional connectivity to be altered during the acute phase of anorexia nervosa (AN), but little is known about the biological mechanisms underlying neural changes associated with weight restoration. The goal of the current study was to investigate longitudinal changes in regional homogeneity (ReHo) among neighboring voxels, degree centrality (DC) (a voxelwise whole brain correlation coefficient), voxel-mirrored homotopic connectivity (VMHC) (measuring the synchronization between hemispheres), and the fractional amplitude of low-frequency fluctuations associated with weight gain during AN treatment. MethodsResting-state functional connectivity data were acquired and analyzed from a sample of 174 female volunteers: 87 underweight patients with AN that were scanned before treatment and again after at least 12% body mass index increase, as well as 87 age-matched healthy control participants. ResultsLongitudinal changes in ReHo, DC, VMHC, and the fractional amplitude of low-frequency fluctuations were observed in most regions identified to differ between patients with AN before treatment and healthy control participants. However, the degree of normalization varied for each parameter, ranging from 9% of all clusters in DC to 66% in VMHC. Longitudinal changes in ReHo and VMHC showed a linear association weight gain. ConclusionsResting-state functional magnetic resonance imaging measures, including ReHo, DC, VMHC, and the fractional amplitude of low-frequency fluctuations, show varying degrees of recovery after short-term weight restoration. Although only some of these changes were related to weight gain, our results provide an overall positive message, suggesting that weight restoration is associated with changes in functional brain measures that point toward normalization.

Heuristic Optimization of PV Energy Penetration to Resilience System Frequency Fluctuation

Heuristic Optimization of PV Energy Penetration to Resilience System Frequency Fluctuation