Search Results (162)

Clinical and animal studies suggest that multiple brain systems are involved in mediating reward-motivated and related emotional behavior including the consumption of commonly used drugs and palatable food, and there is evidence that the repeated ingestion of or exposure to these rewarding substances may in turn stimulate these brain systems to produce an overconsumption of these substances along with co-occurring emotional disturbances. To understand this positive feedback loop, this review focuses on a specific population of hypothalamic peptide neurons expressing melanin-concentrating hormone (MCH), which are positively related to dopamine reward and project to forebrain areas that mediate this behavior. It also examines neurons expressing the peptide hypocretin/orexin (HCRT) that are anatomically and functionally linked to MCH neurons and the molecular systems within these peptide neurons that stimulate their development and ultimately affect behavior. This report first describes evidence in animals that exposure in adults and during adolescence to rewarding substances, such as the drugs alcohol, nicotine and cocaine and palatable fat-rich food, stimulates the expression of MCH as well as HCRT and their intracellular molecular systems. It also increases reward-seeking and emotional behavior, leading to excess consumption and abuse of these substances and neurological conditions, completing this positive feedback loop. Next, this review focuses on the model involving embryonic exposure to these rewarding substances. In addition to revealing a similar positive feedback circuit, this model greatly advances our understanding of the diverse changes that occur in these neuropeptide/molecular systems in the embryo and how they relate, perhaps causally, to the disturbances in behavior early in life that predict a later increased risk of developing substance use disorders. Studies using this model demonstrate in animals that embryonic exposure to these rewarding substances, in addition to stimulating the expression of peptide neurons, increases the intracellular molecular systems in neuroprogenitor cells that promote their development. It also alters the morphology, migration, location and neurochemical profile of the peptide neurons and causes them to develop aberrant neuronal projections to forebrain structures. Moreover, it produces disturbances in behavior at a young age, which are sex-dependent and occur in females more than in males, that can be directly linked to the neuropeptide/molecular changes in the embryo and predict the development of behavioral disorders later in life. These results supporting the close relationship between the brain and behavior are consistent with clinical studies, showing females to be more vulnerable than males to developing substance use disorders with co-occurring emotional conditions and female offspring to respond more adversely than male offspring to prenatal exposure to rewarding substances. It is concluded that the continued consumption of or exposure to rewarding substances at any stage of life can, through such peptide brain systems, significantly increase an individual’s vulnerability to developing neurological disorders such as substance use disorders, anxiety, depression, or cognitive impairments. Full article

Background: Anhedonia, defined as the diminished capacity to experience pleasure, represents a core negative symptom in first-episode psychosis (FEP) with profound implications for functional outcomes and long-term prognosis. Despite its clinical significance, comprehensive understanding of anhedonia prevalence, underlying mechanisms, and optimal intervention strategies in early psychosis remains limited. Objectives: To systematically examine the prevalence and characteristics of anhedonia in FEP patients, explore neurobiological mechanisms, identify clinical correlates and predictive factors, and evaluate intervention efficacy. Methods: Following PRISMA 2020 guidelines, we conducted comprehensive searches across PubMed, Embase, PsycINFO, and Web of Science databases from January 1990 to June 2025. Studies examining anhedonia and negative symptoms in FEP patients (≤24 months from onset) using validated assessment instruments were included. Quality assessment was performed using appropriate tools for study design. Results: Twenty-one studies comprising 3847 FEP patients met inclusion criteria. Anhedonia prevalence ranged from 30% at 10-year follow-up to 53% during acute phases, demonstrating persistent motivational deficits across illness trajectory. Factor analytic studies consistently supported five-factor negative symptom models with anhedonia as a discrete dimension. Neuroimaging investigations revealed consistent alterations in reward processing circuits, including ventral striatum hypofunction and altered network connectivity patterns. Social anhedonia demonstrated stronger associations with functional outcomes compared to other domains. Epigenetic mechanisms involving oxytocin receptor methylation showed gender-specific associations with anhedonia severity. Conventional antipsychotic treatments showed limited efficacy for anhedonia improvement, while targeted psychosocial interventions demonstrated preliminary promise. Conclusions: Anhedonia showed high prevalence (30–53%) across FEP populations with substantial clinical burden (13-fold increased odds vs. general population). Meta-analysis revealed large effect sizes for anhedonia severity in FEP vs. controls (d = 0.83) and strong negative correlations with functional outcomes (r =·−0.82). Neuroimaging demonstrated consistent ventral striatum dysfunction and altered network connectivity. Social anhedonia emerged as the strongest predictor of functional outcomes, with independent suicide risk associations. Conventional antipsychotics showed limited efficacy, while behavioral activation approaches demonstrated preliminary promise. These findings support anhedonia as a distinct treatment target requiring specialized assessment and intervention protocols in early psychosis care. Full article

The electrodynamics of current provide much of our technology, from telegraphs to the wired infrastructure powering the circuits of our electronic technology. Current flow is analyzed by its own rules that involve the Maxwell Ampere law and magnetism. Electrostatics does not involve magnetism, and so current flow and electrodynamics cannot be derived from electrostatics. Practical considerations also prevent current flow from being analyzed one charge at a time. There are too many charges, and far too many interactions to allow computation. Current flow is essential in biology. Currents are carried by electrons in mitochondria in an electron transport chain. Currents are carried by ions in nerve and muscle cells. Currents everywhere follow the rules of current flow: Kirchhoff’s current law and its generalizations. The importance of electron and proton flows in generating ATP was discovered long ago but they were not analyzed as electrical currents. The flow of protons and transport of electrons form circuits that must be analyzed by Kirchhoff’s law. A chemiosmotic theory that ignores the laws of current flow is incorrect physics. Circuit analysis is easily applied to short systems like mitochondria that have just one internal electrical potential in the form of the Hodgkin Huxley Katz (HHK) equation. The HHK equation combined with classical descriptions of chemical reactions forms a computable model of cytochrome c oxidase, part of the electron transport chain. The proton motive force is included as just one of the components of the total electrochemical potential. Circuit analysis includes its role just as it includes the role of any other ionic current. Current laws are now needed to analyze the flow of electrons and protons, as they generate ATP in mitochondria and chloroplasts. Chemiosmotic theory must be replaced by an electro-osmotic theory of ATP production that conforms to the Maxwell Ampere equation of electrodynamics while including proton movement and the proton motive force. Full article

The substantia nigra (SN) has historically been regarded as a pivotal element of the brain’s motor circuits, notably within the context of the nigrostriatal pathway and Parkinson’s disease. However, recent advancements in neuroimaging techniques, particularly tractography, have facilitated the delineation of its anatomical projections. These techniques have revealed the involvement of the SN in a more extensive array of functional networks encompassing cognitive, emotional, and motivational domains. This paper reviews the current knowledge on the structural connectivity of the SN in humans based on diffusion tensor imaging and tractography. It summarizes the main projection pathways, including classical and newly described connections, such as the direct SN pars compacta connections to the thalamus, cortico–neural inputs, and connections to limbic regions and the hippocampus. Furthermore, the text delves into the distinctions between the SN pars compacta and SN pars reticulata subregions, exploring their parcellation based on connectivity. The paper demonstrates that the SN is a functionally diversified nucleus, the implications of which are significant for the understanding of both motor and neuropsychiatric disorders. The present study addresses the paucity of comprehensive treatment in this area and provides a framework for further research on dopaminergic circuits. Full article

Today’s power grids are being modernized with the integration of new technologies, making them increasingly efficient, secure, and flexible. One of these technologies, which is beginning to make great contributions to distribution systems, is solid-state transformers (SSTs), motivating the present technical and economic study of local level 2 distribution systems in Colombia. Taking into account Resolution 015 of 2018 issued by the Energy and Gas Regulatory Commission (CREG), which establishes the economic and quality parameters for the remuneration of electricity operators, the possibility of using these new technologies in electricity networks, particularly distribution networks, was studied. The methodology for developing this study consisted of creating a reference framework describing the topologies implemented in local distribution systems (LDSs), followed by a technical and economic evaluation based on demand management and asset remuneration through special construction units, providing alternatives for the digitization and modernization of the Colombian electricity market. The research revealed the advantages of SST technologies, such as reactive power compensation, surge protection, bidirectional flow, voltage drops, harmonic mitigation, voltage regulation, size reduction, and decreased short-circuit currents. These benefits can be leveraged by distribution network operators to properly manage these types of technologies, allowing them to be better prepared for the transition to smart grids. Full article

The lateral hypothalamic area (LHA) serves as a central integrative hub for the regulation of energy homeostasis and motivational behaviors, including feeding and arousal. Recent advances in single-cell transcriptomics have revealed remarkable molecular heterogeneity within the LHA, identifying more than 30 distinct neuronal subtypes, such as GABAergic (LHA^Vgat), glutamatergic (LHA^Vglut2), orexin, melanin-concentrating hormone (MCH), and leptin receptor-expressing (LHA^Lepr) neurons. These neuronal populations sense peripheral metabolic signals—such as leptin, insulin, and glucose—both directly and indirectly, and they coordinate appropriate physiological and behavioral responses through local circuits and reciprocal connections with other hypothalamic nuclei. Furthermore, the LHA interfaces with extrahypothalamic regions, including the ventral tegmental area (VTA), nucleus accumbens (NAc), and lateral habenula (LHb), thereby linking metabolic state to reward processing and behavioral prioritization. In this review, we summarize and integrate recent molecular and functional findings to present a comprehensive view of the LHA as a dynamic, multifunctional center in the central regulation of metabolism. A deeper understanding of these mechanisms may offer new therapeutic avenues for addressing obesity and related metabolic disorders. Full article

The study of dynamical processes on complex networks constitutes a foundational domain bridging applied mathematics, statistical physics, systems theory, and data science. Temporal evolution, not static topology, determines the controllability, stability, and inference limits of real-world systems, from epidemics and neural circuits to power grids and social media. However, the methodological landscape remains fragmented, with distinct communities advancing separate formalisms for spreading, control, inference, and design. This review presents a unifying six-pillar framework for the analysis of network dynamics: (i) spectral and structural foundations; (ii) deterministic mean-field reductions; (iii) control and observability theory; (iv) adaptive and temporal networks; (v) probabilistic inference and belief propagation; (vi) multilayer and interdependent systems. Within each pillar, we delineate conceptual motivations, canonical models, analytical methodologies, and open challenges. Our corpus, selected via a PRISMA-guided screening of 134 mathematically substantive works (1997–2024), is organized to emphasize internal logic and cross-pillar connectivity. By mapping the field onto a coherent methodological spine, this survey aims to equip theorists and practitioners with a transferable toolkit for interpreting, designing, and controlling dynamic behavior on networks. Full article

Motivated by recent developments in the field of multilevel quantum batteries, we present the model of a quantum device for energy storage with anharmonic level spacing, based on a superconducting circuit in the transmon regime. It is charged via the sequential interaction with a collection of identical and independent ancillary two-level systems. By means of a numerical analysis, we show that, in case these ancillas are coherent, this kind of quantum battery can achieve remarkable performances in terms of the control of the stored energy and its extraction in regimes of parameters within reach in nowadays quantum circuits. Full article

Due to the dynamic increase in the number of prosumer electrical installations in Poland, one may observe many negative effects of their development, including the deterioration of energy quality parameters and the reliability of the existing distribution network. The installation of solar panels in Polish homes was mainly motivated by economic reasons. One of the most important problems of the distribution network is the increase in voltage. The aim of this work was to develop a practical method for determining the maximum voltage changes caused by the connection of photovoltaic installations. To accomplish this, a representative low-voltage overhead line, typical of those found in Poland, was modeled using the NEPLAN software. More than 100 distinct simulations were conducted, exploring various locations and power capacities of photovoltaic installations and utilizing authentic annual profiles for both electrical loads and photovoltaic generation. From the analysis of the data obtained, relationships that enable the determination of voltage changes induced by photovoltaic connections at any node within the low-voltage circuit were established. The computational results derived from this simplified model demonstrate sufficient accuracy for practical applications, and the required input data is accessible to distribution system operators. Full article

Conductive polymers play a crucial role in the advancement of modern technologies, particularly in the field of organic photovoltaics (OPVs). Due to advantages such as flexibility, low specific weight, ease of processing, and low production costs, polymeric materials present an attractive alternative to traditional photovoltaic materials. This study investigates the properties of a polymer blend composed of PCPDTBT (donor) and PNDI(2HD)2T (acceptor), used as the active layer in bulk heterojunction (BHJ) solar cells. The motivation behind this research was the search for a novel n-type polymer material with potentially better properties than the commonly used P(NDI2OD-T2). Comprehensive characterization of thin films made from the individual polymers and their blend was conducted using Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Ultraviolet-Visible Spectroscopy (UV-Vis), four-point probe conductivity measurements, and photovoltaic testing. The prepared films were continuous, uniform, and exhibited low surface roughness (R_a < 2.5 nm). Spectroscopic analysis showed that the blend absorbs light in a broad range of the spectrum, with slight bathochromic shifts compared to individual polymers. Electrical measurements indicated that the blend’s conductivity (9.1 µS/cm) was lower than that of pure PCPDTBT but higher than that of PNDI(2HD)2T, with an optical band gap of 1.34 eV. Photovoltaic devices fabricated using the blend demonstrated an average power conversion efficiency (PCE) of 6.45%, with a short-circuit current of 14.37 mA/cm² and an open-circuit voltage of 0.89 V. These results confirm the feasibility of using PCPDTBT:PNDI(2HD)2T blends as active layers in BHJ solar cells and provide a promising direction for further optimization in terms of polymer ratio and processing conditions. Full article

Military schools primarily aim to prepare young people for the admission procedures of military academies. In this specific environment, the high overall load can generate burnout in cadets and the consequent failure to achieve scholastic and military objectives. The present study investigated how a training protocol based entirely on internal load and a reflective approach in a military-type school context affects participants’ physical efficacy, efficiency, and psychological outcomes. For this study, 63 cadets who were 17 years old from an Italian military school were recruited. Twenty-two of them were allocated into a control group (CG), twenty-one were allocated into a group exercising based on external load (EG), and twenty we allocated into a group exercising based on internal load (IG). All groups performed tests of physical efficacy (maximal tests) and physical efficiency (self-perception-based submaximal test) and answered psychological questionnaires to assess motivation, self-efficacy, and enjoyment. Group participants attended eight weeks of interventions in which physical education lessons were led as follows: the EG performed a circuit training at 50% of maximal repetitions, the IG performed a circuit training at value six on Borg’s scale, and the CG attended curricular physical education lessons. Tests were then repeated. The IG increased physical efficacy more than the EG and CG, while only the IG increased physical efficiency. The IG and EG improved in psychological variables more than the CG. Education in self-perception and self-regulation could help cadets better manage their psychophysical status, allowing them to reach the physical demands for academic admission. Full article

The continuous growth of energy-efficient electronic devices and compact systems has motivated researchers to develop TFTs based on p-type semiconductors. This review examines the developments in p-type thin-film transistors (TFTs) processed using solution methods to achieve integration with complementary metal–oxide–semiconductor technology. Improving organic p-type materials is critical for achieving advanced mobility and stability characteristics with suitable process integration. Scientists study these materials for use in wearable devices which display mechanical strength when fitted onto a curve. This review presents an exclusive discussion about the wide spectrum of applications which involve flexible displays and sensors, together with upcoming technologies such as artificial skin and flexible integrated circuits. The article examines present material challenges, along with device reliability and large-scale production methods, to give a thorough analysis of solution-processed p-type TFTs toward their broad implementation in upcoming electronic devices. By summarizing the developments and most recent studies in the field, this review aims to provide useful information regarding current research into and future trends of p-type TFTs. Full article

A polymer-dispersed liquid crystal (PDLC) film is a device that can transition from opaque to transparent when electrically charged. These films can be used as actuators to control light levels in response to changing natural light. However, the current state of the art for controlling PDLC films is limited to on/off functionality, and few works in the current body of literature have explored continuous control. This study develops a novel nonlinear model for PDLCs in the context of the feedback control of light. This study also demonstrates the model’s utility by comparing experimental data of a PDLC in feedback with a proportional–integral (PI) controller for disturbance rejection and tracking of a desired light setpoint. This development is motivated by the need for a smart greenhouse that can provide programmable optimized light levels for plant growth. Specifically, a light sensor is composed of a circuit with photodiodes and calibrated for the photosynthetically active radiation range. The light sensor is placed under the film, separate from an exogenous light source, allowing for feedback control to be applied. A proportional–integral type control law is selected for stiffness and the ability to eliminate steady-state error, and it is implemented using a microcontroller. An equivalent analog control effort is applied to the PDLC via a PWM voltage signal and an H-bridge type driver. Details necessary for the driving of the PDLC are presented. Open-loop identification of the nonlinear quasi-static and dynamic step-response transients of the PDLC at different control levels are presented and modeled. Finally, closed-loop experimental and simulated results are presented for both light disturbance rejection and setpoint tracking. This shows that the proposed control framework allows for continuous control of light. Full article

This work focuses on evaluating the behavior of analog chaos oscillators in field-programmable gate arrays (FPGAs). This work is motivated by a new approach to designing chaos-based communication systems using chaos oscillator circuits implemented in hardware in the transmitter and the mathematical models of the oscillator implemented on an FPGA in the receiver. Such a hybrid approach opens new possibilities for chaos-based modulation schemes for wireless sensor network (WSN) applications. This work brings a hybrid chaos-based communication system closer to realization by implementing the chaos oscillators on an FPGA and achieving analog–discrete and discrete–analog chaotic synchronization. First, this paper derives a model that simulates the dynamics of Vilnius and RC chaos oscillators using Euler–Cromer numerical integration in fixed-point arithmetic. The derived MATLAB model precisely describes the digital design and is thus directly transferred to VHDL. The synthesized digital design is compiled onto an FPGA chip and is then used to achieve analog–discrete and discrete–analog Pecora–Carroll chaotic synchronization. Full article

This paper addresses the problem of achieving secure consensus control in multi-agent systems (MASs) operating on directed graphs under the challenges of input saturation and periodic denial-of-service (DoS) attacks. The motivation behind this study is to ensure robust performance and security in MASs. To tackle input saturation, a distributed controller is designed using a parametric algebraic Riccati equation-based low-gain output-feedback control approach. This method ensures that control inputs remain within operational limits while maintaining stability. Additionally, leveraging the Lyapunov stability theory, this paper presents a comprehensive analysis of the impact of DoS attacks, focusing on their frequency and average duration, and guarantees semi-global secure consensus under these conditions. Simulation results including a circuit system demonstrate the effectiveness and advantages of the proposed approach. Full article