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A shock-free expansion tunnel nozzle has been designed for the NASA HYPULSE facility at GASL. The main purpose of the nozzle is to increase the available test core size to accommodate a large-scale model, with the initial design intended for aeroheating studies at re-entry flow conditions. The nozzle was designed to expand the hypervelocity flow at the acceleration tube exit to a larger test core size of 30 cm, while maintaining a unit Reynolds number of at least 9.8 x 10 5/m. The two main challenges encountered in the design were the high entrance Mach number and the thick incoming tube-wall boundary layer. The paper discusses the design strategies of using a contour obtained using the method-of-characteristics as opposed to the conical geometry, and the skimmer versus the full-capture approaches, to achieve shock-free uniform exit flow with acceptable Reynolds numbers. To fully characterize the final design, computational fluid dynamics analyses were carried out using the nonuniform viscous flow profile at the acceleration tube exit as a start-line condition. The pitot pressure distribution at nozzle exit, as well as the heat flux on a hemisphere placed at nozzle exit, were calculated and compared with experiments. Besides discussing the fluid dynamic aspects of the design, a short description of a cost-effective manufacturing technique of fabricating the nozzle from fiberglass is also included. [ABSTRACT FROM AUTHOR]

Objective. Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by impaired social interaction and communication, restrictive and repetitive patterns of behavior, interests and activities. The aim of this study was to determine the postnatal levels of thyroid hor-mones and investigate their association with the severity of ASD symptoms. Methods. The study included 56 children (46 boys and 10 girls) with ASD aged 24-42 months. For ASD diagnostics the Autism Diagnostic Observation Schedule - second version (ADOS-2) and the Autism Diagnostic Interview-Revised (ADI-R) - interview with the child's parents or guard-ians were used. Venous blood was drawn right after the diagnostic procedures to analyze serum thyroid-stimulating hormone (s-TSH), free triiodothyronine (s-fT3), and free thyroxine (s-fT4) levels. Linear regression analysis was conducted to assess the relationship between the concentra-tions of thyroid hormones and ASD symptoms severity. Results. Serum concentrations of measured hormones were within normal reference ranges in almost all children. Decline of s-TSH was significantly associated with an increase in the severity of impaired social interaction and impaired communication as rated by parents (ADI-R) and with a higher prevalence of stereotyped behavior as observed in the diagnostic examination (ADOS-2). A decrease in s-fT3 was associated with higher frequency of stereotyped behavior as assessed by parents (ADI-R). Neither sex nor age were significant predictors. Conclusion. Although thyroid hormone levels were normal, we demonstrated an association of thyroid hormones with ASD symptoms., (© 2024 Maria Kopcikova et al., published by Sciendo.)

Despite many studies on dopamine changes in autism, specific alterations in midbrain dopamine neurons projecting to the striatum and cortex remain unclear. Mouse models with diverse SH3 domain and ankyrin repeat containing protein 3 (Shank3) deficiencies are used for investigating autistic symptoms and underlying neurobiological mechanisms. SHANK3 belongs to postsynaptic proteins crucial for synapse formation during development, and disruptions in SHANK3 structure could lead to impaired neurite outgrowth and altered dendritic arborization and morphology. Therefore, we aimed to investigate whether Shank3 deficiency (Shank3B) leads to changes in the morphology of primary neuronal cell cultures from dopaminergic brain regions of neonatal mouse pups and whether it results in alterations in synaptic proteins in dopaminergic nerve pathway projection areas (striatum, frontal cortex). Significantly reduced neurite outgrowth was observed in primary dopaminergic neurons from the midbrain and striatum of Shank3-deficient compared to WT mice. A decrease in Synapsin I immunofluorescence signal in the cortical neurons isolated from Shank3-deficient mice was found, although neurite arborization changes were less severe. Importantly, the deficit in the length of the longest neurite was confirmed in primary cortical neurons isolated from Shank3-deficient mice. No changes in the gene expression of synaptic proteins were observed in the striatum and frontal cortex of Shank3-deficient mice, but an altered gene expression profile of dopaminergic receptors was found. These results show structural changes of dopaminergic neurons, which may explain autistic symptomatology in the used model and provide a basis for understanding the long-term development of autistic symptoms., Competing Interests: Declarations. Ethics Approval: All experimental procedures followed the ethical guidelines for animal experiments and were approved by the Ethical Committee of the Faculty of Medicine, Comenius University in Bratislava, Slovak Republic. The mice were handled and cared for in accordance with the Guide for the Care and Use of Laboratory Animals (N.R.C., 1996) and the European Communities Council Directive of September 22nd, 2010 (2010/63/EU, 74). Consent to Participate: Not applicable. Consent for Publication: Not applicable. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s).)

The neurobiology of autism is complex, but emerging research points to potential abnormalities and alterations in neurogenesis. The aim of the present review is to describe the advances in the understanding of the role of selected neurotrophins, neuropeptides, and other compounds secreted by neuronal cells in the processes of postnatal neurogenesis in conjunction with autism. We characterize the fundamental mechanisms of neuronal cell proliferation, generation of major neuronal cell types with special emphasis on neurogenic niches - the subventricular zone and hippocampal areas. We also discuss changes in intracellular calcium levels and calcium-dependent transcription factors in the context of the regulation of neurogenesis and cell fate determination. To sum up, this review provides specific insight into the known association between alterations in the function of the entire spectrum of molecules involved in neurogenesis and the etiology of autism pathogenesis.

Objective: Despite the growing number of female medical students, there remains a significant disparity between the number of female and male neurosurgeons. This study aims to determine if this trend is also evident among medical students, examine how various medical schools worldwide are addressing this issue, and propose potential solutions., Methods: The data includes anonymous baseline information from congress registrations, the abstract submission system, and two surveys designed to assess student experiences before and after the congress. The questionnaires covered socioeconomic background, prior congress experience, knowledge assessment, career aspirations, and perceptions of neurosurgery, using various Likert scales. Data analysis was performed using GraphPad Prism., Results: A total of 171 individuals attended the congress, including 90 women (52.6%). Pre- and post-congress surveys were completed by 27 participants (48.2% female, 51.9% male). Women submitted more abstracts (59.0%) and achieved higher presentation rankings. Both groups rated their interest in pursuing a career in neurosurgery at 5 out of 6. However, women rated the likelihood of achieving a work-life balance in neurosurgery at 4 out of 6, compared to 3 out of 6 by men. After the congress, this rating improved by one point on the Likert scale for both groups., Conclusion: This study highlights gender-based differences in career planning, scientific and practical neurosurgery experiences, and mentoring opportunities during medical education. Initiatives such as congresses and mentoring programs could help address this imbalance by supporting female medical students from the early stages of their careers., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Oxytocin affects social recognition, interactions, and behavior in adults. Despite growing data on the role of oxytocin in the sensory systems, its effects on early olfactory system development remain poorly understood. The present study aimed to investigate the developmental impact of oxytocin on selected parameters of the GABAergic system in olfactory brain regions. We found a significant increase in the expression of GABAergic markers and scaffolding proteins in the olfactory bulb during the early stages of development in both male and female rats, regardless of oxytocin treatment administered on postnatal days 2 and 3 (P2 and P3, 5 µg/pup). Oxytocin administration markedly reduced the expression of the scaffolding protein Gephyrin in male rats and it led to a significant increase in the number of GABAergic synaptic puncta in the piriform cortex of male rats at P5, P7, and P9. Our data suggest that the developmental action of oxytocin in relation to the GABAergic system may represent a mechanism by which the plasticity and maturation of olfactory brain regions are regulated., Competing Interests: Declaration of competing interest The authors declare they have no conflicts of interest., (Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.)

The development of new chiral ligands with simple and modular structure represents a challenging direction in the design of efficient homogeneous transition metal catalysts. Herein, we report on the asymmetric hydrogenation of prochiral ketones catalyzed by the iridium complexes of simple alkane-diyl-based P,N,O-type chiral ligands with a highly modular structure. The role of (i) the P-N and N-O backbone in the potentially tridentate ligands, (ii) the number, position and relative configuration of their stereogenic elements and (iii) the effect of their NH and OH subunits on the activity and enantioselectivity of the catalytic reactions are studied. The systematic variation in the ligand structure and the comparative catalytic experiments shed light on different mechanistic aspects of the iridium-catalyzed reaction. The catalysts containing the simple alkane-diyl-based ligands with central chirality provided high enantioselectivities (up to 98% ee ) under optimized reaction conditions and proved to be active and selective even at very high substrate concentrations (100 mmol substrate/mL solvent).

Oxytocin plays an important role in brain development and is associated with various neurotransmitter systems in the brain. Abnormalities in the production, secretion, and distribution of oxytocin in the brain, at least during some stages of the development, are critical for the pathogenesis of neuropsychiatric diseases, particularly in the autism spectrum disorder. The etiology of autism includes changes in local sensory and dopaminergic areas of the brain, which are also supplied by the hypothalamic sources of oxytocin. It is very important to understand their mutual relationship. In this review, the relationship of oxytocin with several components of the dopaminergic system, gamma-aminobutyric acid (GABA) inhibitory neurotransmission and their alterations in the autism spectrum disorder is discussed. Special attention has been paid to the results describing a reduced expression of inhibitory GABAergic markers in the brain in the context of dopaminergic areas in various models of autism. It is presumed that the altered GABAergic neurotransmission, due to the absence or dysfunction of oxytocin at certain developmental stages, disinhibits the dopaminergic signaling and contributes to the autism symptoms., (© 2024 Tomas Havranek et al., published by Sciendo.)

Dysfunctional sensory systems, including altered olfactory function, have recently been reported in patients with autism spectrum disorder (ASD). Disturbances in olfactory processing can potentially result from gamma-aminobutyric acid (GABA)ergic synaptic abnormalities. The specific molecular mechanism by which GABAergic transmission affects the olfactory system in ASD remains unclear. Therefore, the present study aimed to evaluate selected components of the GABAergic system in olfactory brain regions and primary olfactory neurons isolated from Shank3-deficient ( -/- ) mice, which are known for their autism-like behavioral phenotype. Shank3 deficiency led to a significant reduction in GEPHYRIN/GABA A R colocalization in the piriform cortex and in primary neurons isolated from the olfactory bulb, while no change of cell morphology was observed. Gene expression analysis revealed a significant reduction in the mRNA levels of GABA transporter 1 in the olfactory bulb and Collybistin in the frontal cortex of the Shank3 -/- mice compared to WT mice. A similar trend of reduction was observed in the expression of Somatostatin in the frontal cortex of Shank3 -/- mice. The analysis of the expression of other GABAergic neurotransmission markers did not yield statistically significant results. Overall, it appears that Shank3 deficiency leads to changes in GABAergic synapses in the brain regions that are important for olfactory information processing, which may represent basis for understanding functional impairments in autism., (© 2024. The Author(s).)

Despite an accumulating number of studies, treatments for depression are currently insufficient. Therefore, the search for new substances with antidepressant potential is very important. In this study, we hypothesized that treatment with a newly synthesized pyridoindole derivative compound SMe1EC2M3 would result in protective and antidepressant-like effects on behavioral outcomes and reverse the impaired adult hippocampal neurogenesis caused by chronic mild stress (CMS). We found that chronic administration of 5 mg/kg and 25 mg/kg SMe1EC2M3 to adult Sprague Dawley rats ameliorated the consequences of CMS on immobility and swimming time in a forced swim test. A slight sedative effect of the highest dose of SMe1EC2M3 in the nonstress group was observed in the open field. SMe1EC2M3 in the highest dose ameliorated CMS-induced decreases in the sucrose preference test. Administration of SMe1EC2M3 significantly increased SOX2-positive cells in the hippocampal dentate gyrus (DG) in CMS compared to control animals. A significant reduction in glial fibrillary acid protein (GFAP)-positive cells in the DG of CMS compared to control animals was observed. Administration of both 5 and 25 mg/kg SMe1EC2M3 significantly increased signal of GFAP-positive cells in the DG of CMS animals. No such effects of SMe1EC2M3 were observed in the cornu ammonis hippocampal area. Additionally, we found that incubation of primary hippocampal neurons in the presence of 1.50 µM SMe1EC2M3 significantly stimulated the length of neurites. Overall, we found that the negative effects of CMS on depression-like behavior are partially reduced by the administration of SMe1EC2M3 and are associated with changes in hippocampal neurogenesis and neuronal differentiation. SMe1EC2M3 represents a potential drug candidate with positive neuroplastic effects and neurogenesis-associated effects in therapeutic approaches to depression.

Neuropeptide oxytocin appears to be involved in the formation of hippocampal circuitry, underlying social memory and behaviour. Recent studies point to the role of oxytocin in regulating the levels of nerve growth factors that could influence neurogenesis and neuritogenesis during the early stages of brain development. Therefore, the aim of the present study was to evaluate the early developmental effect of oxytocin administration (P2 and P3 days, two doses, 5 μg/pup, s.c.) on the expression of 1) brain-derived neurotrophic factor (BDNF) isoforms and 2) GABAergic and glutamatergic markers in the male rat hippocampus. Furthermore, we evaluated the branching of dendrites of primary hippocampal GABAergic and glutamatergic neurons in response to incubation with oxytocin (1 μM). We found that after oxytocin administration, levels of proBDNF increased on P5 and mBDNF on P7 in the CA1 hippocampal region. We also observed a reduction in the expression of glutamatergic marker (VGluT2) on P7 compared to P5 in control and oxytocin treated rats. During the early developmental stages (P5, P7, P9) the expression of GABAergic markers (Gad65 and Gad67) decreased regardless of oxytocin treatment. Incubation in a presence of oxytocin reduced branching of glutamatergic hippocampal neurons and the opposite stimulatory effect of oxytocin was observed in GABAergic neurons. These findings suggest that oxytocin affects neurotrophin isoforms in the male rat hippocampus in the early stages of development, which could explain changes in glutamatergic neurons and their morphology., Competing Interests: Declaration of Competing Interest Authors declare no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In the human environment, the increasing exposure to radiofrequency (RF) radiation, especially that emitted by wireless devices, could be absorbed in the body. Recently, mobile and emerging wireless technologies (UMTS, DECT, LTE, and Wi-Fi) have been using higher frequencies than 2G GSM systems (900/1800 MHz), which means that most of the circulating RF currents are absorbed into the skin and the superficial soft tissue. The harmful genotoxic, cytotoxic, and mutagenic effects of solar ultraviolet (UV) radiation on the skin are well-known. This study aimed at investigating whether 2422 MHz (Wi-Fi) RF exposure combined with UV radiation in different sequences has any effect on the inflammation process in the skin. In vitro experiments examined the inflammation process by cytokines (IL-1α, IL-6, IL-8) and MMP-1 enzyme secretion in a 3D full-thickness human skin model. In the first study, UV exposure was immediately followed by RF exposure to measure the potential additive effects, while in the second study, the possible protective phenomenon (i.e., adaptive response) was investigated when adaptive RF exposure was challenged by UV radiation. Our results suggest that 2422 MHz Wi-Fi exposure slightly, not significantly increased cytokine concentrations of the prior UV exposure. We could not detect the adaptive response phenomenon.

Despite the known importance of the endoplasmic reticulum (ER) in protein synthesis and vesicular transport, it is not clear whether neuropeptide and neuromodulator oxytocin can directly affect components of the ER in neuronal cells. Therefore, in the present study, we hypothesize that incubation of hippocampal neuronal cells in a presence of oxytocin 1) plays a role in the regulation of the expression of selected ER chaperone components and molecules involved in unfolded protein response pathway 2) affects distribution of the intracellular fluorescence signal highly selective for the ER. We found that oxytocin (1 μM) after 60 min significantly decreased the gene expression of oxidoreductase Ero1β, chaperone glucose-regulated proteins (Grp) 78 and Grp94. A significant decrease in GRP78 protein levels in response to oxytocin treatment occurred after 30, 60 and 120 min. We also observed a time-dependent increase in calreticulin protein levels with a statistically significant increase observed after 360 min. We found that the dynamics of the ER network changes significantly within 2 h of incubation under the influence of oxytocin. In conclusion we have shown that ER chaperones, oxidoreductases and trafficking molecules in neuronal cells are changing in response to oxytocin treatment in a short-term scenario potentially relevant for growth of dendrites and axons., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Non-biodegradable plastics are continually amassing landfills and oceans worldwide while creating severe environmental issues and hazards to animal and human health. Plastic pollution has resulted in the death of millions of seabirds and aquatic animals. The worldwide production of plastics in 2020 has increased by 36% since 2010. This has generated significant interest in bioplastics to supplement global plastic demands. Bioplastics have several advantages over conventional plastics in terms of biodegradability, low carbon footprint, energy efficiency, versatility, unique mechanical and thermal characteristics, and societal acceptance. Bioplastics have huge potential to replace petroleum-based plastics in a wide range of industries from automobiles to biomedical applications. Here we review bioplastic polymers such as polyhydroxyalkanoate, polylactic acid, poly-3-hydroxybutyrate, polyamide 11, and polyhydroxyurethanes; and cellulose-based, starch-based, protein-based and lipid-based biopolymers. We discuss economic benefits, market scenarios, chemistry and applications of bioplastic polymers., Competing Interests: Conflict of interestNone declared., (© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2021.)