Switched CMOS current source compared to enhanced Howland circuit for bio-impedance applications.

Bio-impedance Spectroscopy (BIS) is a technique that allows tissue analysis to diagnose a variety of diseases, such as medical imaging, cancer diagnosis, muscle fatigue detection, glucose measurement, and others under research. The development of CMOS integrated circuit front-ends for bioimpedance analysis is required by the increasing use of wearable devices in the healthcare field, as they offer key features for battery-powered wearable devices. These features include high miniaturization, low power consumption, and low voltage power supply. A key circuit in BIS systems is the current source, and one of the most common topology is the Enhanced Howland Current Source (EHCS). EHCS is also used when the current driver is driven by a pseudo-random signal like discrete interval binary sequences (DIBS), which, due to its broadband nature, requires high performance operational amplifiers. These facts lead to the need for a current source more compatible with DIBS signals, ultra-low power supply, standard CMOS integrated circuit, output current amplitude independent of input voltage amplitude, high output impedance, high load capability, high output voltage swing, and the possibility of tetra-polar BIS analysis, that is a pseudotetra-polar in the case of EHCS. The objective of this work is to evaluate the performance of the Switching CMOS Current Source (SCMOSCS) over EHCS using a Cole-skin model as a load using SPICE simulations (DC and AC sweeps and transient analysis). The SCMOSCS demonstrated an output impedance of more than 20 MΩ, a ± 2.5 V output voltage swing from a +3.3 V supply, a 275 µA current consumption, and a 10 kΩ load capacity. These results contrast with the + 1.5 V output voltage swing, the 3 kΩ load capacity, and the 4.9 mA current of the EHCS case.

Early Development of the Thalamo-Pallial Stage of the Tectofugal Visual Pathway in the Chicken (Gallus gallus).

The tectofugal pathway is a highly conserved visual pathway in all amniotes. In birds and mammals, retinorecipient neurons located in the midbrain roof (optic tectum/superior colliculus) are the source of ascending projections to thalamic relays (nucleus rotundus/caudal pulvinar), which in turn project to specific pallial regions (visual dorsal ventricular ridge [vDVR]/temporal cortex) organized according to a columnar recurrent arrangement of interlaminar circuits. Whether or to which extent these striking hodological correspondences arise from comparable developmental processes is at present an open question, mainly due to the scarcity of data about the ontogeny of the avian tectofugal system. Most of the previous developmental studies of this system in birds have focused on the establishment of the retino-tecto-thalamic connectivity, overlooking the development of the thalamo-pallial-intrapallial circuit. In this work, we studied the latter in chicken embryos by means of immunohistochemical assays and precise ex vivo crystalline injections of biocytin and DiI. We found that the layered organization of the vDVR as well as the system of homotopic reciprocal connections between vDVR layers were present as early as E8. A highly organized thalamo-vDVR projection was also present at this stage. Our immunohistochemical assays suggest that both systems of projections emerge simultaneously even earlier. Combined with previous findings, these results reveal that, in striking contrast with mammals, the peripheral and central stages of the avian tectofugal pathway develop along different timelines, with a tecto-thalamo-intrapallial organization arising before and possibly independently of the retino-isthmo-tectal circuit.

Signal, detection and estimation using a hybrid quantum circuit.

We investigate a hybrid device allowing a photon-phonon coupling of a transmission line radiation (TLR) and a nanoeletromechanical system (NEMS), mediated by a superconducting qubit population imbalance. We demonstrate the derivation of an effective Hamiltonian for the strongly dispersive regime for this system. The qubit works as a quantum switch, allowing a conditioned transfer of excitations between the TLR and NEMS. We show that this regime allows the system to be employed for signal processing and force estimation. Additionally, we explore the ability of the quantum switch to generate non-classical states.

Open Circuit Interaction Between Ethanol or 2-Propanol and Oxidized Platinum Surfaces.

The interaction between organic molecules and oxidized catalyst surfaces has frequently been used to study the fuel crossover from the anode to the cathode in direct liquid fuel cells. In such experiments, the oxidized surface is put in contact with the fuel under open circuit conditions, and the evolution of the potential is registered. The open circuit potential (OCP) vs. time features can then inform on the reactivity of the fuel with the oxidized surface and provide valuable information not only to applications in fuel cells but also to the electrochemical reform of those molecules to produce clean hydrogen. In this paper, we present an experimental investigation of the open circuit interaction between ethanol or 2-propanol with oxidized platinum surfaces. Besides the OCP time traces, we have also employed cyclic voltammetry and fast oxide reduction sweep in the presence of the alcohols. Comparable reaction currents are obtained in the cyclic voltammogram, but the electro-oxidation of 2-propanol sets in at considerably lower overpotentials than that of ethanol. At the high potential region, both the magnitude and the potential of the current peak are nearly identical in both cases. In contrast, under open circuit conditions, the interaction of ethanol with the oxidized platinum surface is more pronounced than that found for 2-propanol, and these results are corroborated by the facile reduction of the platinum oxides along the fast backward sweep for the case of the latter.

Random number generator based on a memristive circuit.

In this paper we discuss the details, limitations, and difficulties of the implementation in hardware of a memristor-based random number generator that exhibits monofractal/multifractal behavior. To do so, the components and selection criteria of a reference memristor and one proposed by the authors, the chaotic circuit leveraging them, and the processing that is performed on the chaotic signals to achieve the random discrete sequences are described. After applying the estimation tools, findings indicate that more than 60% of the proposed combinations allow generating random discrete sequences, with long-range dependence, and that both monofractal and multifractal behaviors can also be obtained. Consequently, a hardware system was achieved that can be used as a source of entropy in future synthetic biological signal generators.

Disinhibition Is an Essential Network Motif Coordinated by GABA Levels and GABA B Receptors.

Network dynamics are crucial for action and sensation. Changes in synaptic physiology lead to the reorganization of local microcircuits. Consequently, the functional state of the network impacts the output signal depending on the firing patterns of its units. Networks exhibit steady states in which neurons show various activities, producing many networks with diverse properties. Transitions between network states determine the output signal generated and its functional results. The temporal dynamics of excitation/inhibition allow a shift between states in an operational network. Therefore, a process capable of modulating the dynamics of excitation/inhibition may be functionally important. This process is known as disinhibition. In this review, we describe the effect of GABA levels and GABAB receptors on tonic inhibition, which causes changes (due to disinhibition) in network dynamics, leading to synchronous functional oscillations.

Anticoagulation in renal replacement therapies: Why heparin should be abandoned in critical ill patients?

Extracorporeal circuits used in renal replacement therapy (RRT) can develop thrombosis, leading to downtimes and reduced therapy efficiency. To prevent this, anticoagulation is used, but the optimal anticoagulant has not yet been identified. Heparin is the most widely used anticoagulant in RRT, but it has limitations, such as unpredictable pharmacokinetics, nonspecific binding to plasma proteins and cells, and the possibility of suboptimal anticoagulation or bleeding complications, specifically in critically ill patients with acute renal failure who are already at high risk of bleeding. Citrate anticoagulation is a better alternative, being considered a standard for continuous renal replacement therapy, since it is associated with a lower risk of bleeding complications and better efficacy, even in patients with acute renal failure or liver disease. The aim of this article is to provide an updated review of the different strategies of anticoagulation in renal replacement therapies that can be implemented in critical scenarios, focusing on the advantages and disadvantages of each one and the beneficial aspects of using citrate over heparin in critical ill patients.

Contamination of equipment and surfaces in the operating room anesthesia workspace: a cross-sectional study

ABSTRACT BACKGROUND: Contamination of the breathing circuit and medication preparation surface of an anesthesia machine can increase the risk of cross-infection. OBJECTIVE: To evaluate the contamination of the anesthetic medication preparation surface, respiratory circuits, and devices used in general anesthesia with assisted mechanical ventilation. DESIGN AND SETTING: Cross-sectional, quantitative study conducted at the surgical center of a philanthropic hospital, of medium complexity located in the municipality of Três Lagoas, in the eastern region of the State of Mato Grosso do Sul. METHODS: Eighty-two microbiological samples were collected from the breathing circuits. After repeating the samples in different culture media, 328 analyses were performed. RESULTS: A higher occurrence of E. coli, Enterobacter spp., Pseudomonas spp., Staphylococcus aureus, and Streptococcus pneumoniae (P < 0.001) were observed. Variations were observed depending on the culture medium and sample collection site. CONCLUSION: The study findings underscore the inadequate disinfection of the inspiratory and expiratory branches, highlighting the importance of stringent cleaning and disinfection of high-touch surfaces.

Dopamine, Norepinephrine and Serotonin Participate Differently in Methylphenidate Action in Concomitant Behavioral and Ventral Tegmental Area, Locus Coeruleus and Dorsal Raphe Neuronal Study in Young Rats.

Methylphenidate (MPD), known as Ritalin, is a psychostimulant used to treat children, adults, and the elderly. MPD exerts its effects through increasing concentrations of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in the synaptic cleft. Concomitant behavioral and neuronal recording from the ventral tegmental area (VTA), locus coeruleus (LC), and from the dorsal raphe (DR) nucleus, which are the sources of DA, NE, and 5-HT to the mesocorticolimbic circuit, were investigated following acute and repetitive (chronic) saline, 0.6, 2.5, or 10.0 mg/kg MPD. Animals received daily saline or MPD administration on experimental days 1 to 6 (ED1-6), followed by a 3-day washout period and MPD rechallenge on ED10. Each chronic MPD dose elicits behavioral sensitization in some animals while inducing behavioral tolerance in others. The uniqueness of this study is in the evaluation of neuronal activity based on the behavioral response to chronic MPD. Neuronal excitation was observed mainly in brain areas of animals exhibiting behavioral sensitization, while neuronal attenuation following chronic MPD was observed in animals expressing behavioral tolerance. Different ratios of excitatory/inhibitory neuronal responses were obtained from the VTA, LC, or DR following chronic MPD. Thus, each brain area responds differently to each MPD dose used, suggesting that DA, NE, and 5-HT in the VTA, LC, and DR exert different effects.

Altitude Diving on a Closed Circuit Oxygen Rebreather.

Closed-circuit rebreather diving is becoming more common. Rebreathers are complicated, adding to the stress of diving. Also adding to this complexity in the presented case is diving at a high-altitude, cold-water reservoir in Colorado. One diver experienced an oxygen-induced seizure at depth. The other diver had a rapid ascent with loss of consciousness. In this case, two experienced divers recovered from a possible devastating dive. Fortunately, they both returned to their pre-dive baseline health. Dive plan- ning is important, but as in this case, dive execution is paramount. This is a clinical case for an uncommon event presenting to an emergency department.

Modeling of Ammunition Dynamic Pressure Measurement Chain in Ballistic Tests.

The use of piezoelectric transducers for internal dynamic pressure measurements in ammunition testing provides a significant advantage in the development and performance analysis of weapons and ammunition. Knowledge of the electrical characteristics of the dynamic pressure measurement chain, which includes the piezoelectric transducer and the charge amplifier, is a relevant condition for the design of interior ballistics pressure measurement systems. Thus, this study aims to characterize and model a piezoelectric transducer and its associated charge amplifier. First, the piezoelectric transducer was characterized using impedance analysis and modeled using a least squares curve-fitting tool, according to the Butterworth-Van Dyke model. Next, the charge amplifier was characterized through response analysis based on known inputs and modeled using LTSpice simulation techniques and the least squares curve-fit tool. Consequently, a measurement chain model is presented and simulated for two cases with different impulse signals. The first impulse signal was obtained from an interior ballistics computer simulation, and in the second case, it was considered the negative step signal characteristic of the calibration of piezoelectric transducers by means of dead weight. From the simulations, it was possible to verify the effectiveness of the model, which provided results with a low error in relation to the original pressure curve, and its applicability is demonstrated by the result of the simulation of the pressure variation in the calibration, where the attenuation of the signal can be visualized as the characteristic of the input curve changes.

Preventing Production Escape Using an Engineered Glucose-Inducible Genetic Circuit.

A proper balance of metabolic pathways is crucial for engineering microbial strains that can efficiently produce biochemicals on an industrial scale while maintaining cell fitness. High production loads can negatively impact cell fitness and hinder industrial-scale production. To address this, fine-tuning gene expression using engineered promoters and genetic circuits can promote control over multiple targets in pathways and reduce the burden. We took advantage of the robust carbon catabolite repression system of Bacillus subtilis to engineer a glucose-inducible genetic circuit that supports growth and production. The circuit is resilient, enabling a quick switch in the production status when exposed to the correct carbon source. By performing serial cultivations for 61 generations under repressive conditions, we preserved the production capacity of the cells, which could be fully accessed by switching to glucose in the next cultivation step. Switching to glucose after 61 generations resulted in 34-fold activation and generated 70% higher production in comparison to standard cultivation in glucose. Conversely, serial cultivation under permanent induction resulted in 62% production loss after 67 generations alongside an increase in the culture growth rate. As a pathway-independent circuit activated by the preferred carbon source, our engineered glucose-inducible genetic circuit is broadly useful and imposes no additional cost to traditional production processes.

Neonatal overfeeding alters the functioning of the mesolimbic dopaminergic circuitry involving changes in DNA methylation and effects on feeding behavior.

Mesolimbic dopaminergic circuit is essential for food reward and motivational behaviors and can contribute to weight gain and obesity. Litter reduction is a classical model for studying the effects of neonatal overfeeding and overweight. Litters of Wistar rats were reduced to 4 pups/dam for small litter (SL) and 10 pups/dam for normal litter at postnatal day (PND) 4. Immediately after performing the feeding behavior tests, the animals were sacrificed in PND21 and PND90. The ventral tegmental area (VTA), Nucleus Accumbens Core (NAcC) and Shell (NAcSh) were isolated from frozen brain sections using the Palkovits micropunch technique. RNA and DNA were extracted from these areas, gene expression was measured by RT-qPCR and DNA methylation levels were measured by MSRM-qPCR technique. SL-PND21 animals presented increased expression levels of Tyrosine Hydroxylase and Dopamine Receptor D2 in VTA, decreased expression levels of dopamine active transporter (DAT) in VTA, and higher expression levels of DAT in NAcC. On the other hand, SL-PND90 animals showed decreased expression levels of Dopamine Receptor D1 and higher expression of DAT in NAcSh. These animals also evidenced impaired sensory-specific satiety. In addition, altered promoter methylation was observed at weaning, and remained in adulthood. This work demonstrates that neonatal overfeeding induces disruptions in the mesolimbic dopaminergic circuitry and causes alterations in feeding behavior from weaning to adulthood, suggesting that the neonatal period is critical for the normal development of dopaminergic circuit that impact on feeding behavior.

Face-to-face and telerehabilitation delivery of circuit training have similar benefits and acceptability in patients with knee osteoarthritis: a randomised trial.

QUESTION: Is periodised circuit training delivered via a telerehabilitation model of care as effective as the same training applied face-to-face for improving pain intensity, physical function, muscle strength, pain catastrophising, body composition, intermuscular adipose tissue and muscle architecture in people with knee osteoarthritis (OA)? DESIGN: Randomised controlled, non-inferiority trial with concealed allocation, blinded assessors and intention-to-treat analysis. PARTICIPANTS: One hundred adults aged ≥ 40 years with knee OA and pain for ≥ 3 months, with current pain ≥ 40 mm on a 100-mm visual analogue scale (VAS). INTERVENTION: The experimental group received 14 weeks of circuit training delivered via telerehabilitation using video recordings, followed by periodic phone calls in order to motivate and instruct participants. The control group received the same circuit training program in a face-to-face format. OUTCOME MEASURES: The primary outcomes were pain VAS and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale, measured at 14 weeks. Secondary outcomes included objective physical function, strength, pain catastrophising and morphological measures (muscle architecture and thigh and body composition). Outcomes were measured at 14 and 26 weeks. RESULTS: Periodised circuit training delivered via telerehabilitation had equivalent effects to face-to-face delivery for pain intensity, physical function, muscle strength, pain catastrophising, thigh composition, intermuscular adipose tissue and muscle architecture. Whole body composition did not change appreciably in either group. Adherence to the training was excellent and participants in each group reported good perceptions of their randomised intervention. CONCLUSION: A periodised circuit training protocol can be delivered to people with knee OA in their own homes, using available technology while maintaining high levels of acceptability. More importantly, telerehabilitation appears to cause non-inferior physical and functional outcomes to face-to-face rehabilitation programs. TRIAL REGISTRATION: RBR-662hn2.

Christofredo Jakob, los cimientos de la neurociencia argentina / Christofredo Jakob, the foundations of argentine neuroscience

El presente artículo es una reseña biográfica de la vida del Dr. Christofredo Jakob, desde su formación en Alemania, las personalidades que acompañaron su desarrollo y las publicaciones científicas en suelo germano. Luego llegarían los inicios de su trabajo en la Argentina y los principales alcances de sus investigaciones. A través de esta reseña recorremos los comienzos del estudio sistemático del sistema nervioso en el país y recordamos el Día del Neurocientífico argentino. (AU)

This article is a biographical review of the life of Dr. Christofredo Jakob, from his training in Germany, the personalities who accompanied his development and the scientific publications on German soil. Then came the beginnings of his work in Argentina and the main achievements of his research. Through this review, we retrace the beginnings of the systematic study of the nervous system in the country and we remember the Day of the Argentine Neuroscientist. (AU)

Obesity-mediated Lipoinflammation Modulates Food Reward Responses.

Accumulation of white adipose tissue (WAT) during obesity is associated with the development of chronic low-grade inflammation, a biological process known as lipoinflammation. Systemic and central lipoinflammation accumulates pro-inflammatory cytokines including IL-6, IL-1ß and TNF-α in plasma and also in brain, disrupting neurometabolism and cognitive behavior. Obesity-mediated lipoinflammation has been reported in brain regions of the mesocorticolimbic reward circuit leading to alterations in the perception and consumption of ultra-processed foods. While still under investigation, lipoinflammation targets two major outcomes of the mesocorticolimbic circuit during food reward: perception and motivation ("Wanting") and the pleasurable feeling of feeding ("Liking"). This review will provide experimental and clinical evidence supporting the contribution of obesity- or overnutrition-related lipoinflammation affecting the mesocorticolimbic reward circuit and enhancing food reward responses. We will also address neuroanatomical targets of inflammatory profiles that modulate food reward responses during obesity and describe potential cellular and molecular mechanisms of overnutrition linked to addiction-like behavior favored by brain lipoinflammation.

Understanding the Effect of Deposition Technique on the Structure-Property Relationship of Polyaniline Thin Films Applied in Potentiometric pH Sensor.

The comprehension of potentiometric pH sensors with polymeric thin films for new and advanced applications is a constant technological need. The present study aimed to explore the relationship between the sensitivity and correlation coefficient of potentiometric pH sensors and the structure-property relationship of polyaniline thin films. The effect of the deposition method on the sample's properties was evaluated. Galvanostatically electrodeposited and spin-coated polyaniline thin films were used as the sensing stage. Samples were electrodeposited with a current density of 0.5 mA/cm2 for 300, 600, and 1200 s and were spin coated for 60 s with an angular velocity of 500, 1000, and 2000 rpm. The electrodeposited set of films presented higher average sensitivity, 73.4 ± 1.3 mV/pH, compared to the spin-coated set, 59.2 ± 2.5 mV/pH. The electrodeposited films presented higher sensitivity due to their morphology, characterized by a larger roughness and thickness compared to spin-coated ones, favoring the potentiometric response. Also, their oxidation state, evaluated with cyclic voltammetry and UV-VIS spectroscopy, corroborates their sensing performance. The understanding of the structure-property relationship of the polymeric films affecting the pH detection is discussed based on the characteristics of the deposition method used.

Design and validation of a multilevel voltage source inverter based on modular H-bridge cells.

Generation, power conversion and subsequent integration of renewable energy generation systems, such as solar photovoltaic or wind, require an efficient power conversion system that can provide sufficient quality energy according to technical standards (e.g. IEEE 519-2022). In this context, this paper focuses on the analysis, design and experimental validation of a multilevel voltage source inverter (VSI) scheme based on H-bridge cells with a modular and scalable structure for its application in power electronic converter circuits. The designed and assembled experimental setup is a versatile platform for testing experimentally varied control strategies and power converter configurations, such as the number of levels (3, 5, 7 levels) and phases (single-phase or three-phase). Therefore, the hardware design process proposed for the H-bridge cell and the measurement and conditioning circuits for voltage and current signals necessary for implementing the control algorithms are explained in detail. Moreover, a quantitative analysis of the operation of the design was carried out from measurements made with the experimental platform to verify its correct operation. Among the analysed parameters, the generated harmonics level stands out, quantified by calculating the total harmonic distortion and the mean square error between the reference signals and the measured values.

The endogenous cannabinoid system modulates male sexual behavior expression.

The endocannabinoid system (ECS) plays a key neuromodulatory role in the brain. Main features of endocannabinoids (eCBs) are that they are produced on demand, in response to enhanced neuronal activity, act as retrograde messengers, and participate in the induction of brain plasticity processes. Sexual activity is a motivated behavior and therefore, the mesolimbic dopaminergic system (MSL) plays a central role in the control of its appetitive component (drive to engage in copulation). In turn, copulation activates mesolimbic dopamine neurons and repeated copulation produces the continuous activation of the MSL system. Sustained sexual activity leads to the achievement of sexual satiety, which main outcome is the transient transformation of sexually active male rats into sexually inhibited animals. Thus, 24 h after copulation to satiety, the sexually satiated males exhibit a decreased sexual motivation and do not respond to the presence of a sexually receptive female with sexual activity. Interestingly, blockade of cannabinoid receptor 1 (CB1R) during the copulation to satiety process, interferes with both the appearance of the long-lasting sexual inhibition and the decrease in sexual motivation in the sexually satiated males. This effect is reproduced when blocking CB1R at the ventral tegmental area evidencing the involvement of MSL eCBs in the induction of this sexual inhibitory state. Here we review the available evidence regarding the effects of cannabinoids, including exogenously administered eCBs, on male rodent sexual behavior of both sexually competent animals and rat sub populations spontaneously showing copulatory deficits, considered useful to model some human male sexual dysfunctions. We also include the effects of cannabis preparations on human male sexual activity. Finally, we review the role played by the ECS in the control of male sexual behavior expression with the aid of the sexual satiety phenomenon. Sexual satiety appears as a suitable model for the study of the relationship between eCB signaling, MSL synaptic plasticity and the modulation of male sexual motivation under physiological conditions that might be useful for the understanding of MSL functioning, eCB-mediated plasticity and their relationship with motivational processes.

Ancilla-Assisted Generation of Photons from Vacuum via Time-Modulation of Extracavity Qubit.

We propose a scheme for the generation of photons from a vacuum via time-modulation of a quantum system indirectly coupled to the cavity field through some ancilla quantum subsystem. We consider the simplest case when the modulation is applied to an artificial two-level atom (we call 't-qubit', that can be located even outside the cavity), while the ancilla is a stationary qubit coupled via the dipole interaction both to the cavity and t-qubit. We find that tripartite entangled states with a small number of photons can be generated from the system ground state under resonant modulations, even when the t-qubit is far detuned from both the ancilla and the cavity, provided its bare and modulation frequencies are properly adjusted. We attest our approximate analytic results by numeric simulations and show that photon generation from vacuum persists in the presence of common dissipation mechanisms.