Baltic Institute of Advanced Technology

Optical adiabatons are specific shape-invariant pulse pairs propagating at the reduced group velocity and without optical absorption in the medium. The purpose of this study is to analyze and demonstrate adiabaton formation in many level atomic systems. Here we focus on the analysis of five level M-type and double tripod systems. It is found that M-type atomic systems are prone to intensity dependent group velocity and pulse front steepening which prevents the formation of long range optical adiabatons. In contrast, the double tripod atomic system is quite favorable for the formation of optical adiabatons leading to two different optical field configurations propagating with invariant shape.

Lithium/sodium metal batteries have become a pivotal focus in the field of rechargeable batteries due to their potential to offer the highest specific capacity and lowest operating voltage. However, this high energy density brings significant instability between the lithium/sodium metal anode and the electrolyte. This instability can lead to uneven lithium/sodium deposits, known as dendrites or mossy type deposits, and uncontrolled formation of solid electrolyte interphases (SEIs), which further impede the ionic transport of working ions at the interface. Understanding the origins of morphological evolution, side reactions, and ion transport at the alkali metal/electrolyte interface is crucial for improving the cycle life of lithium/sodium metal batteries. Solid-state NMR, with its ability to provide detailed information about the chemistry, morphology, and ionic dynamics, is becoming an indispensable technique for studying metal anodes. In this review, we first introduce the basics of NMR in studying metal anodes and then select specific examples to illustrate how various NMR methods, including multinuclear magic angle spinning (MAS) NMR, electrochemical in situ NMR, and NMR dynamics methods, provide unique insights into the chemical composition of SEIs, deposit morphological evolution, and ionic dynamics at the lithium metal/electrolyte interface.

Bidirectional communication between neurons and glial cells is crucial to establishing and maintaining normal brain function. Some of these interactions are activity-dependent, yet it remains largely unexplored how acute changes in neuronal activity affect glial-to-neuron and neuron-to-glial dynamics. Here, we use excitatory and inhibitory designer receptors exclusively activated by designer drugs (DREADD) to study the effects of acute chemogenetic manipulations of a subpopulation of layer 5 cortical projection and dentate gyrus neurons in adult (Rbp4Cre) mouse brains. We show that acute chemogenetic neuronal activation reduces synaptic density, and increases microglia and astrocyte reactivity, but does not affect parvalbumin (PV+) neurons, only perineuronal nets (PNN). Conversely, acute silencing increases synaptic density and decreases glial reactivity. We show fast glial response upon clozapine-N-oxide (CNO) administration in cortical and subcortical regions. Together, our work provides evidence of fast, activity-dependent, bidirectional interactions between neurons and glial cells.

Abstract Communication between neurons and glial cells are crucial to establish and maintain brain function. Some of these interactions are activity-dependent, yet it remains unexplored how acute changes in neuronal activity affect neuron-to-glial dynamics. Here, we use excitatory and inhibitory designer receptors exclusively activated by designer drugs (DREADD) based chemogenetic methods to study the effects of acute manipulations of a subpopulation of layer 5 cortical projection and dentate gyrus neurons in adult (Rbp4Cre) mouse brain after 90 minutes. We show that acute chemogenetic neuronal activation leads to microglia hyperactivation, reactive astrogliosis, increased parvalbumin expression in interneurons and lower synaptic marker expression. Whereas acute chemogenetic ‘silencing’ of the same neurons reduce microglia activity, inhibit astrocytic reactivity, increase synaptic density, but has no effect on parvalbumin expression. Acute changes in neuronal activity elicit rapid effects on the interactions between glial cells, glutamatergic and GABAergic neuronal networks.

The project European active electronically scanned array with Combined Radar, Electronic Warfare (EW) and Communications (COMMs) functions for military applications, called CROWN, was launched in July 2021 under the European program of Preparatory Action for Defence Research (PADR) and Electromagnetic Spectrum Dominance Call. It responds to the need of designing and developing high-performance and very compact Multifunction RF systems. Multifunction systems, integrating several functions in only one single system, enable small platforms operating in the complex battlefield of high capabilities, able to adapt and react in real-time to the changing scenarios and working in collaborative way with other systems. Technological challenges are found in the development of broadband antennas, digital beam forming (DBF), smart resource management and compact transmit and receive modules. Other aspects at system level as architecture definition or modelling are also tackled within the project.

Chalcogenide phase change materials (PCMs), featuring a large contrast in optical properties between their non-volatile amorphous and crystalline states, have triggered a surge of interest for their applications in ultra-compact photonic integrated circuits with long-term near-zero power consumption. Over the past decade, however, PCM-integrated photonic devices and networks suffered from the huge optical loss of various commonly-used PCMs themselves. In this paper, we focused on the deposition, characterization, and monolithic integration of an emerging low-loss phase change material, Sb2Se3 on a silicon photonic platform. The refractive index contrast between the amorphous and crystalline phase of the evaporated Sb-Se thin film was optimized up to 0.823 while the extinction coefficient remains less than 10−5 measured by ellipsometry. When integrated on a silicon waveguide, the propagation loss introduced by the amorphous thin film is negligibly low. After crystallization, the propagation loss of a magnetron-sputtered Sb-Se patch-covered silicon waveguide is as low as 0.019 dB/µm, while its thermal-evaporated counterpart is below 0.036 dB/µm.

The enhanced permeability and retention effect allows for passive targeting of solid tumours by nanoparticles carrying anticancer drugs. However, active targeting by incorporation of various ligands onto nanoparticles can provide for a more selective and enhanced chemotherapeutic effect and complement the deficiencies of the passive targeting approach. Here we report on the design of the carboxyl-terminated PEGylated gold nanoparticles (AuNPs), their functionalization with anti-CD133 monoclonal antibody (mAb) via a crosslinking reaction, and subsequent 5-fluorouracil (5-FU) drug loading. The synthesized products in the form of stable colloids were characterised using a range of physicochemical techniques, including X-ray diffraction (XRD), UV-Vis spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). Conjugation of anti-CD133 mAb onto PEGylated AuNPs was confirmed with the use of UV-Vis, BCA protein assay and fluorescence microscopy. HCT116 colorectal cancer cells abundantly expressed CD133: 92.4 ± 1.3%, as measured by flow cytometry. Whereas PEGylated AuNPs not conjugated with anti-CD133 mAb accumulated mainly at the cellular membrane, nanoparticles conjugated with anti-CD133 mAb were contained within the nuclear region of the cells. Anti-CD133 mAb conjugation facilitated the specific intracellular uptake due to specific antigen–antibody binding interaction. In vitro cytotoxicity studies on HCT116 cells showed that PEGylated AuNPs and PEGylated AuNPs-CD133 did not elicit any toxicity at any of the tested concentrations. Meanwhile, 5-FU-PEGylated AuNPs-CD133 significantly reduced the cell viability relative to the treatment with 5-FU-PEGylated AuNPs without anti-CD133 mAb conjugates (p < 0.0001). This study shows that the conjugation of nanocarriers with the anti-CD133 antibody improves the specific targeting of 5-FU against colorectal cancer cells. These results demonstrate that simultaneous functionalisation of PEGylated AuNPs with antibodies and chemotherapeutic drugs is a viable strategy to combat cancer through targeted drug delivery.

Hexavalent chromium is a widespread pollutant that threatens ecological and human health. However, its removal from the environment is limited by the high cost and energy consumption rate of current technologies. In this study, the Cr(vi) biosorption mechanism of Aspergillus niger spores pretreated by freezing/thawing was studied by batch experiments and surface chemistry analyses. The results indicated that pretreatment enhanced the spores' Cr(vi) removal efficiency. The cell surface, internal functional groups, and morphology of the freezing/thawing-pretreated spores (FTPS) before and after Cr(vi) loading were characterized by advanced spectroscopy techniques such as SEM-EDAX, XPS, FTIR, and FETEM analyses. The SEM and BET data showed that the surface of FTPS was rougher than that of untreated spores. The XPS data showed that FTPS bio-transformed Cr(vi) into Cr(iii). The intracellular localization of chromium was visualized by FETEM, and both surface and intracellular structures removed Cr(vi) following pseudo-second-order biosorption kinetics. The biosorption dynamics of Cr(vi) fit the Langmuir isotherm model describing a monolayer. These results suggest that freezing/thawing pretreatment of A. niger spores could lead to the development of a novel, efficient biomaterial for the removal of Cr(vi).

The purpose of this paper is to analyse the possibility for predicting the outcome of a road traffic accident concerning the traffic environment, personal traits of the traffic participant and the vehicle, i.e. aiming to answer the question whether specific values of the factors analysed to increase the likelihood of a fatal accident. The logistic regression model that allows identifying the relationship between the dependent and independent variables were used in the research. Other methods for describing and analysing categorical variables were also used alongside the logistic regression. When analysing the results, it was recognised that the odds ratio above 1 shows a higher likelihood for a representative of the category in question to be involved in a fatal accident compared to a representative of the base category. Odds ratios of likelihoods for calculation of the road traffic accident types show that the likelihood of a fatal accident is statistically significant affected by rollovers or driving into obstacles, compared to vehicular collisions. When summarising the results, it was stated that most of the factors researched have an impact on the outcome of a road traffic accident. The influence of some factors has a higher probability of resulting in a fatal accident as compared to other factors.

Machine reading is a fundamental task for testing the capability of natural language understand- ing, which is closely related to human cognition in many aspects. With the rising of deep learning techniques, algorithmic models rival human performances on simple QA, and thus increasingly challenging machine reading datasets have been proposed. Though various challenges such as evidence integration and commonsense knowledge have been integrated, one of the fundamental capabilities in human reading, namely logical reasoning, is not fully investigated. We build a comprehensive dataset, named LogiQA, which is sourced from expert-written questions for testing human Logical reasoning. It consists of 8,678 QA instances, covering multiple types of deductive reasoning. Results show that state-of-the-art neural models perform by far worse than human ceiling. Our dataset can also serve as a benchmark for reinvestigating logical AI under the deep learning NLP setting. The dataset is freely available at https://github.com/lgw863/LogiQA-dataset.