Local Noise Spectroscopy of Wigner Crystals in Two-Dimensional Materials.

We propose local electromagnetic noise spectroscopy as a versatile and noninvasive tool to study Wigner crystal phases of strongly interacting two-dimensional electronic systems. In-plane imaging of the local noise is predicted to enable single-site resolution of the electron crystal when the sample-probe distance is less than the interelectron separation. At larger sample-probe distances, noise spectroscopy encodes information about the low-energy Wigner crystal phonons, including the dispersion of the transverse shear mode, the pinning resonance due to disorder, and optical modes emerging, for instance, in bilayer crystals. We discuss the potential utility of local noise probes in analyzing the rich set of phenomena expected to occur in the vicinity of the melting transition.

Cascade Synthesis of Pyrrolo[1,2-a]quinolines and Pyrrolo[2,1-a]isoquinolines via Formal [3 + 2]-Cycloaddition of Push-Pull Nitro Heterocycles with Carbonyl-Stabilized Quinolinium/Isoquinolinium Ylides.

Various substituted pyrrolo[1,2-a]quinolines and pyrrolo[2,1-a]isoquinolines were synthesized in good to high yields by the Et3N-mediated reaction of push-pull 3-nitrobenzofurans or 1-Ts-/1-Ms-3-nitroindoles and precursors of carbonyl-stabilized quinolinium and isoquinolinium ylides as 1,3-dipole equivalents. These transformations proceed in a one-pot manner starting with the formal [3 + 2]-cycloaddition stage, which is accompanied by double dearomatization of both quinoline/isoquinoline and benzofuran/indole moieties, followed by ring-opening of cyclic intermediate formed and nitrous acid elimination sequence. [3 + 2]-Cycloadducts were isolated as the final products in cases of impossibility or difficulty of their enolization. The present protocol was successfully extended to 3-nitro-4H-chromene derivatives as push-pull dipolarophile component. Finally, using the method of competing reactions, the reactivity of the starting compounds was compared with each other.

The Interactions of Temporal and Sensory Representations in the Basal Ganglia.

In rodents and primates, interval estimation has been associated with a complex network of cortical and subcortical structures where the dorsal striatum plays a paramount role. Diverse evidence ranging from individual neurons to population activity has demonstrated that this area hosts temporal-related neural representations that may be instrumental for the perception and production of time intervals. However, little is known about how temporal representations interact with other well-known striatal representations, such as kinematic parameters of movements or somatosensory representations. An attractive hypothesis suggests that somatosensory representations may serve as the scaffold for complex representations such as elapsed time. Alternatively, these representations may coexist as independent streams of information that could be integrated into downstream nuclei, such as the substantia nigra or the globus pallidus. In this review, we will revise the available information suggesting an instrumental role of sensory representations in the construction of temporal representations at population and single-neuron levels throughout the basal ganglia.

Elastic Properties of Aging Human Hematoma Model In Vitro and Its Susceptibility to Histotripsy Liquefaction.

OBJECTIVE: Tissue susceptibility to histotripsy disintegration has been reported to depend on its elastic properties. This work was aimed at investigation of histotripsy efficiency for liquefaction of human hematomas, depending on their stiffness and degree of retraction over time (0-10 d). METHODS: As an in vitro hematoma model, anticoagulated human blood samples (200 mL) were recalcified at different temperatures. In one set of samples, the shear modulus was measured by shear wave elastography during blood clotting at 10℃, 22℃ and 37℃, and then daily during further aging. The ultrastructure of the samples was analyzed daily with scanning electron microscopy (SEM). Another set of blood samples (50-200 mL) were recalcified at 37℃ for density and retraction measurements over aging and exposed to histotripsy at varying time points. Boiling histotripsy (2.5 ms pulses) and hybrid histotripsy (0.2 ms pulses) exposures (2 MHz, 1% dc, P+/P-/As = 182/-27/207 MPa in situ) were used to produce either individual cigar-shaped or volumetric (0.8-3 mL) lesions in samples incubated for 3 h, 5 d and 10 d. The obtained lesions were sized, then the lysate aspirated under B-mode guidance was analyzed ultrastructurally and diluted in distilled water for sizing of residual fragments. RESULTS: It was found that clotting time decreased from 113 to 25 min with the increase in blood temperature from 10℃ to 37℃. The shear modulus increased to 0.53 ± 0.17 kPa during clotting and remained constant within 8 d of incubation at 2℃. Sample volumes decreased by 57% because of retraction within 10 d. SEM revealed significant echinocytosis but unchanged ultrastructure of the fibrin meshwork. Liquefaction rate and lesion dimensions produced with the same histotripsy protocols correlated with the increase in the degree of retraction and were lower in retracted samples versus freshly clotted samples. More than 80% of residual fibrin fragments after histotripsy treatment were shorter than 150 µm; the maximum length was 208 µm, allowing for unobstructed aspiration of the lysate with most clinically used needles. CONCLUSION: The results indicate that hematoma susceptibility to histotripsy liquefaction is not entirely determined by its stiffness, and correlates with the retraction degree.

Elastic Waves Excitation and Focusing by a Piezoelectric Transducer with Intermediate Layered Elastic Metamaterials with and without Periodic Arrays of Interfacial Voids.

Optimization of the structure of piezoelectric transducers such as the proper design of matching layers can increase maximum wave energy transmission to the host structure and transducer sensitivity. A novel configuration of an ultrasonic transducer, where elastic metamaterial insertion is introduced to provide bulk wave mode conversion and to increase wave energy transfer into a substrate, is proposed. Configurations of layered elastic metamaterials with crack-like voids are examined theoretically since they can provide wide band gaps and strong wave localization and trapping. The analysis shows that the proposed metamaterial-based matching layers can sufficiently change wave energy transmission from a piezoelectric active element for various frequency ranges (relatively low frequencies as well as higher ones). The proposed configuration can also be useful for advanced sensing with higher sensitivity in certain frequency ranges or for demultiplexing different kinds of elastic waves.

A Dy-based single ion magnet in a SrLaGaO4 matrix: enhanced parameters in an expanded crystal lattice.

Dy3+ doped SrLaGaO4 exhibits unusually slow relaxation of magnetization determined by two widely separated excited Kramers doublets with a second remagnetization energy barrier of 223 cm-1. This value considerably exceeds that for analogous Ca(Y,Dy)AlO4 in spite of the apparently enlarged Dy3+ coordination sphere.

Alteration of Postural Reactions in Rats with Different Levels of Dopamine Depletion.

Dopamine (DA) is the critical neurotransmitter involved in the unconscious control of muscle tone and body posture. We evaluated the general motor capacities and muscle responses to postural disturbance in three conditions: normal DA level (wild-type rats, WT), mild DA deficiency (WT after administration of α-methyl-p-tyrosine-AMPT, that blocks DA synthesis), and severe DA depletion (DAT-KO rats after AMPT). The horizontal displacements in WT rats elicited a multi-component EMG corrective response in the flexor and extensor muscles. Similar to the gradual progression of DA-related diseases, we observed different degrees of bradykinesia, rigidity, and postural instability after AMPT. The mild DA deficiency impaired the initiation pattern of corrective responses, specifically delaying the extensor muscles' activity ipsilaterally to displacement direction and earlier extensor activity from the opposite side. DA depletion in DAT-KO rats after AMPT elicited tremors, general stiffness, and akinesia, and caused earlier response to horizontal displacements in the coactivated flexor and extensor muscles bilaterally. The data obtained show the specific role of DA in postural reactions and suggest that this experimental approach can be used to investigate sensorimotor control in different dopamine-deficient states and to model DA-related diseases.

Self-Organized Memristive Ensembles of Nanoparticles Below the Percolation Threshold: Switching Dynamics and Phase Field Description.

Percolative memristive networks based on self-organized ensembles of silver and gold nanoparticles are synthesized and investigated. Using cyclic voltammetry, pulse and step voltage excitations, we study switching between memristive and capacitive states below the percolation threshold. The resulting systems demonstrate scale-free (self-similar) temporal dynamics, long-term correlations, and synaptic plasticity. The observed plasticity can be manipulated in a controlled manner. The simplified stochastic model of resistance dynamics in memristive networks is testified. A phase field model based on the Cahn-Hilliard and Ginzburg-Landau equations is proposed to describe the dynamics of a self-organized network during the dissolution of filaments.

National sex- and age-specific burden of blindness and vision impairment by cause in Mexico in 2019: a secondary analysis of the Global Burden of Disease Study 2019.

Background: Reliable national estimations for blindness and vision impairment are fundamental to assessing their burden and developing public health policies. However, no comprehensive analysis is available for Mexico. Therefore, in this observational study we describe the national burden of blindness and vision loss by cause and severity during 2019. Methods: Using public data from the Global Burden of Disease (GBD) study 2019, we present national prevalence and years lived with disability (YLDs) counts and crude and age-standardized rates (per 100,000 people) of total, severity- and cause-specific blindness and vision impairment with 95% uncertainty intervals (UIs) by sex and age group. Findings: In Mexico, the burden of blindness and vision impairment was estimated at 11.01 million (95% UI, 9.25-13.11) prevalent cases and 384.96 thousand (259.57-544.24) YLDs during 2019. Uncorrected presbyopia caused the highest burden (6.06 million cases, 4.36-8.08), whereas severe vision loss and blindness affected 619.40 thousand (539.40-717.73) and 513.84 thousand (450.59-570.98) people, respectively. Near vision loss and refraction disorders caused 78.7% of the cases, whereas neonatal disorders and age-related macular degeneration were among the least frequent. Refraction disorders were the main cause of moderate and severe vision loss (61.44 and 35.43%), and cataracts were the second most frequent cause of blindness (26.73%). Females suffered an overall higher burden of blindness and vision impairment (54.99% and 52.85% of the total cases and YLDs), and people >50 years of age suffered the highest burden, with people between 70 and 74 years being the most affected. Interpretation: Vision loss represents a public health problem in Mexico, with women and older people being the most affected. Although the causes of vision loss contribute differentially to the severity of visual impairment, most of the impairment is avoidable. Consequently, a concerted effort at different levels is needed to alleviate this burden. Funding: This study received no funding.

Using temperature to analyze the neural basis of a time-based decision.

The basal ganglia are thought to contribute to decision-making and motor control. These functions are critically dependent on timing information, which can be extracted from the evolving state of neural populations in their main input structure, the striatum. However, it is debated whether striatal activity underlies latent, dynamic decision processes or kinematics of overt movement. Here, we measured the impact of temperature on striatal population activity and the behavior of rats, and compared the observed effects with neural activity and behavior collected in multiple versions of a temporal categorization task. Cooling caused dilation, and warming contraction, of both neural activity and patterns of judgment in time, mimicking endogenous decision-related variability in striatal activity. However, temperature did not similarly affect movement kinematics. These data provide compelling evidence that the timecourse of evolving striatal activity dictates the speed of a latent process that is used to guide choices, but not continuous motor control. More broadly, they establish temporal scaling of population activity as a likely neural basis for variability in timing behavior.

D1 and D2 neurons in the nucleus accumbens enable positive and negative control over sugar intake in mice.

Although the consumption of carbohydrates is needed for survival, their potent reinforcing properties drive obesity worldwide. In turn, sugar overconsumption reveals a major role for brain reward systems in regulating sugar intake. However, it remains elusive how different cell types within the reward circuitries control the initiation and termination of sugary meals. Here, we identified the distinct nucleus accumbens cell types that mediate the chemosensory versus postprandial properties of sweet sugars. Specifically, D1 neurons enhance sugar intake via specialized connections to taste ganglia, whereas D2 neurons mediate the termination of sugary meals via anatomical connections to circuits involved in appetite suppression. Consistently, D2, but not D1, neurons partially mediate the satiating effects of glucagon-like peptide 1 (GLP-1) agonists. Thus, these nucleus accumbens cell types function as a behavioral switch, enabling positive versus negative control over sugar intake. Our study contributes to unveiling the cellular and circuit substrates of sugar overconsumption.

An ultra-high-entropy rare earth orthoferrite (UHE REO): solution combustion synthesis, structural features and ferrimagnetic behavior.

A novel ultra-high-entropy rare earth orthoferrite (UHE REO) of Sc1/16Y1/16La1/16Ce1/16Pr1/16Nd1/16Sm1/16Eu1/16Gd1/16Tb1/16Dy1/16Ho1/16Er1/16Tm1/16Yb1/16Lu1/16FeO3 nominal composition was successfully synthesized for the first time through a simple and efficient solution combustion approach. PXRD, Raman, and 57Fe Mössbauer spectroscopy confirmed the high chemical and phase purity of the synthesized UHE REO (hereafter denoted as ΣREFeO3), which belonged to the Pnma space group, typical of the perovskite-like rare earth orthoferrites. Despite the fact that the main X-ray reflections, vibration modes, and spectral Mössbauer components unambiguously indicate the single-phase nature of the sample, the results of SEM and TEM make it possible to establish the presence of a main (about 50 nm) and a minor ultrafine (about 10 nm) fraction of ΣREFeO3 nanoparticles. The bimodal size distribution of nanoparticles was also reflected in the magnetic behavior of this substance: the presence of several sextet components in the Mössbauer spectra, the hard single-domain magnetic nature of the main fraction of 50 nm UHE REO nanoparticles, and the superparamagnetic state of the minor fraction of 10 nm UHE REO nanoparticles. Thus, the unusual features of nanostructured ΣREFeO3 can potentially be used for the creation of new generations of transformers, magnetic memory systems, magnetic screens, radio devices, etc.

Amniotic Membrane Biopolymer for Regenerative Medicine.

Biopolymers based on the amniotic membrane compare favorably with synthetic materials in that, along with a specific 2D structure, they have biologically active properties. However, in recent years, there has been a tendency to perform decellularization of the biomaterial during the preparation of the scaffold. In this study, we studied the microstructure of 157 samples and identified individual biological components in the manufacture of a medical biopolymer from an amniotic membrane using various methods. Group 1 had 55 samples, and the amniotic membrane was impregnated with glycerol and dried over silica gel. Group 2 had 48 samples, and the decellularized amniotic membrane was impregnated with glycerol followed by lyophilization, Group 3 had 44 samples, and the decellularized amniotic membrane without pre-impregnation with glycerol was subjected to lyophilization. Decellularization was performed by treatment with a low-frequency ultrasound at a frequency of 24-40 kHz in an ultrasonic bath. A morphological study using a light microscope and a scanning electron microscope showed the preservation of the structure of the biomaterial and more complete decellularization in samples subjected to lyophilization without prior impregnation with glycerol. The study of the Raman spectroscopy lines of a biopolymer made from a lyophilized amniotic membrane without preliminary impregnation with glycerin showed significant differences in the intensity of the spectral lines of amides, glycogen, and proline. Additionally, in these samples, the spectral lines of Raman scattering the characteristic of glycerol were not visualized; therefore, only biological substances characteristic of the native amniotic membrane have been preserved.

Blood ACE Phenotyping for Personalized Medicine: Revelation of Patients with Conformationally Altered ACE.

Background: The angiotensin-converting enzyme (ACE) metabolizes a number of important peptides participating in blood pressure regulation and vascular remodeling. Elevated blood ACE is a marker for granulomatous diseases and elevated ACE expression in tissues is associated with increased risk of cardiovascular diseases. Objective and Methodology: We applied a novel approach -ACE phenotyping-to find a reason for conformationally impaired ACE in the blood of one particular donor. Similar conformationally altered ACEs were detected previously in 2-4% of the healthy population and in up to 20% of patients with uremia, and were characterized by significant increase in the rate of angiotensin I hydrolysis. Principal findings: This donor has (1) significantly increased level of endogenous ACE inhibitor in plasma with MW less than 1000; (2) increased activity toward angiotensin I; (3) M71V mutation in ABCG2 (membrane transporter for more than 200 compounds, including bilirubin). We hypothesize that this patient may also have the decreased level of free bilirubin in plasma, which normally binds to the N domain of ACE. Analysis of the local conformation of ACE in plasma of patients with Gilbert and Crigler-Najjar syndromes allowed us to speculate that binding of mAbs 1G12 and 6A12 to plasma ACE could be a natural sensor for estimation of free bilirubin level in plasma. Totally, 235 human plasma/sera samples were screened for conformational changes in soluble ACE. Conclusions/Significance: ACE phenotyping of plasma samples allows us to identify individuals with conformationally altered ACE. This type of screening has clinical significance because this conformationally altered ACE could not only result in the enhancement of the level of angiotensin II but could also serve as an indicator of free bilirubin levels.

Preliminary exploration of direct mercury speciation in solid samples by using thermal release coupled to electrothermal atomic absorption spectrometry.

It is known that monitoring of mercury and notably its species is very important to assess their impact and distribution in the environment. In this regard, the development of a methodology for mercury speciation in natural and man-made media is of particular importance. There are a variety of studies in this area associated with the application of thermal release in combination with electrothermal atomic absorption detection for direct mercury speciation in solid samples without preliminary extraction of analytes. Nevertheless, a number of issues remain that hinder its practical application as a reliable analytical method. However, in order to achieve progress in this field, it is necessary to understand the features of the evaporation process itself. The goal of this work is to study the thermal behavior of the most common mercury species in order to eliminate the gaps in this approach. At this stage, studies were carried out using pure substances and their mixtures as a starting point for a subsequent transition to real natural samples. For this the installation scheme was modernized by introducing a module that provides programmable heating of the sample and variation of the heating rate. As a result of the experiments it was shown that the transformation of studied compounds with the examples of mercury chloride, methylmercury chloride, mercury sulfide and mercury sulfate occurs under thermal exposure, which leads to a change in their physicochemical characteristics, but, nevertheless, does not prevent their baseline separation for 30 min using programmable heating mode, which includes a continuous increase in temperature with a subsequent stop until the thermal peak is formed.

Efficient Production of Segmented Carbon Nanofibers via Catalytic Decomposition of Trichloroethylene over Ni-W Catalyst.

The catalytic utilization of chlorine-organic wastes remains of extreme importance from an ecological point of view. Depending on the molecular structure of the chlorine-substituted hydrocarbon (presence of unsaturated bonds, intermolecular chlorine-to-hydrogen ratio), the features of its catalytic decomposition can be significantly different. Often, 1,2-dichloroethane is used as a model substrate. In the present work, the catalytic decomposition of trichloroethylene (C2HCl3) over microdispersed 100Ni and 96Ni-4W with the formation of carbon nanofibers (CNF) was studied. Catalysts were obtained by a co-precipitation of complex salts followed by reductive thermolysis. The disintegration of the initial bulk alloy driven by its interaction with the reaction mixture C2HCl3/H2/Ar entails the formation of submicron active particles. It has been established that the optimal activity of the pristine Ni catalyst and the 96Ni-4W alloy is provided in temperature ranges of 500-650 °C and 475-725 °C, respectively. The maximum yield of CNF for 2 h of reaction was 63 g/gcat for 100Ni and 112 g/gcat for 96Ni-4W catalyst. Longevity tests showed that nickel undergoes fast deactivation (after 3 h), whereas the 96Ni-4W catalyst remains active for 7 h of interaction. The effects of the catalyst's composition and the reaction temperature upon the structural and morphological characteristics of synthesized carbon nanofibers were investigated by X-ray diffraction analysis, Raman spectroscopy, and electron microscopies. The initial stages of the carbon erosion process were precisely examined by transmission electron microscopy coupled with elemental mapping. The segmented structure of CNF was found to be prevailing in a range of 500-650 °C. The textural parameters of carbon product (SBET and Vpore) were shown to reach maximum values (374 m2/g and 0.71 cm3/g, respectively) at the reaction temperature of 550 °C.

Postnatal growth of the lumbosacral spinal segments in cat: Their lengths and positions in relation to vertebrae.

Cat is a prominent model for investigating neural networks of the lumbosacral spinal cord that control locomotor and visceral activity. We previously proposed an integral function, establishing the topographical relationship between the spinal cord segments and vertebrae in adult animals. Here, we investigated the dynamic of this topographical relationship through early and middle periods of development in kittens. We calculated the length of each vertebra relative to the total length of the region from 13th thoracic (T) to the 7th lumbar (L) vertebrae (V) as well as the length of each segment relative to the total region from T13 to the three-dimensional sacral (S) segment. As in our previous work, the length and position of VL2 were used to establish relationships between the characteristics of the segments and vertebrae. Cubic regression reliably approximates the lengths of segments relative to VL2 length. As the cat aged, the relative length of VT13 and VL1 decreased while the relative length of VL5 increased. The relative length of the T13 and L3 segments increased while the relative length of the S1-S2 segments decreased. The T13-L2 segments are descended monotonically relative to the VL1-VL2 border. The L3-S1 segments are also descended, though with more complex dynamics. The positions of the S2-S3 segments remained unchanged. To conclude, different spinal segments displayed different developmental dynamics. The revealed relationship between vertebrae and lumbosacral spinal segments may be helpful for clearly defining stimulation regions to invoke particular functions, both in experimental studies on the spinal cord and clinical treatment.

Adsorption kinetics of NO2 gas on oxyfluorinated graphene film.

We report the fabrication of high-performance NO2 gas sensors based on oxyfluorinated graphene (OFG) layers. At room temperature, the times of adsorption/desorption of NO2 on/from the surface of thin OFG films are less than 1200 s and can be reduced by increasing the operation temperature. The sensors are capable of detecting NO2 molecules at sub-ppm level with a sensitivity of 0.15 ppm-1 at 348 K. The temperature dependence of the rate constants shows that the simultaneous presence of a large number of fluorine- and oxygen-containing groups on the graphene surface provides the formation of low-energy sites (ΔHa < 0.1 eV) for NO2 adsorption. The combination of the high sensitivity of the sensor and a reasonable adsorption/desorption time of the analyte is promising for on-line monitoring.

Porous Co-Pt Nanoalloys for Production of Carbon Nanofibers and Composites.

The controllable synthesis of carbon nanofibers (CNF) and composites based on CNF (Metals/CNF) is of particular interest. In the present work, the samples of CNF were produced via ethylene decomposition over Co-Pt (0-100 at.% Pt) microdispersed alloys prepared by a reductive thermolysis of multicomponent precursors. XRD analysis showed that the crystal structure of alloys in the composition range of 5-35 at.% Pt corresponds to a fcc lattice based on cobalt (Fm-3m), while the CoPt (50 at.% Pt) and CoPt3 (75 at.% Pt) samples are intermetallics with the structure P4/mmm and Pm-3m, respectively. The microstructure of the alloys is represented by agglomerates of polycrystalline particles (50-150 nm) interconnected by the filaments. The impact of Pt content in the Co1-xPtx samples on their activity in CNF production was revealed. The interaction of alloys with ethylene is accompanied by the generation of active particles on which the growth of nanofibers occurs. Plane Co showed low productivity (~5.5 g/gcat), while Pt itself exhibited no activity at all. The addition of 15-25 at.% Pt to cobalt catalyst leads to an increase in activity by 3-5 times. The maximum yield of CNF reached 40 g/gcat for Co0.75Pt0.25 sample. The local composition of the active alloyed particles and the structural features of CNF were explored.

Mild cognitive impairment is associated with low copy number of ribosomal genes in the genomes of elderly people.

Introduction: Mild cognitive impairments (MCI) accompanying aging are associated with oxidative stress. The ability of cells to respond to stress is determined by the protein synthesis level, which depends on the ribosomes number. Ribosomal deficit was documented in MCI. The number of ribosomes depends, together with other factors, on the number of ribosomal genes copies. We hypothesized that MCI is associated with low rDNA CN in the elderly person genome. Materials and Methods: rDNA CN and the telomere repeat (TR) content were determined in the DNA of peripheral blood leukocytes of 93 elderly people (61-91 years old) with MCI and 365 healthy volunteers (16-91 years old). The method of non-radioactive quantitative hybridization of DNA with biotinylated DNA probes was used for the analysis. Results: In the MCI group, rDNA CN (mean 329 ± 60; median 314 copies, n = 93) was significantly reduced (p < 10-15) compared to controls of the same age with preserved cognitive functions (mean 412 ± 79; median 401 copies, n = 168) and younger (16-60 years) control group (mean 426 ± 109; median 416 copies, n = 197). MCI is also associated with a decrease in TR DNA content. There is no correlation between the content of rDNA and TR in DNA, however, in the group of DNA samples with rDNA CN > 540, TR content range was significantly narrowed compared to the rest of the sample. Conclusion: Mild cognitive impairment is associated with low ribosomal genes copies in the elderly people genomes. A low level of rDNA CN may be one of the causes of ribosomal deficit that was documented in MCI. The potential possibilities of using the rDNA CN indicator as a prognostic marker characterizing human life expectancy are discussed.