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Of all publications in the section: 592
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Article
Dubois J., Kulikova S., Hertz-Pannier L. et al. Magnetic Resonance Imaging. 2014. Vol. 32. No. 8. P. 981-992.
Objective

Diffusion imaging techniques such as DTI and HARDI are difficult to implement in infants because of their sensitivity to subject motion. A short acquisition time is generally preferred, at the expense of spatial resolution and signal-to-noise ratio. Before estimating the local diffusion model, most pre-processing techniques only register diffusion-weighted volumes, without correcting for intra-slice artifacts due to motion or technical problems. Here, we propose a fully automated strategy, which takes advantage of a high orientation number and is based on spherical-harmonics decomposition of the diffusion signal.

Material and methods

The correction strategy is based on two successive steps: 1) automated detection and resampling of corrupted slices; 2) correction for eddy current distortions and realignment of misregistered volumes. It was tested on DTI data from adults and non-sedated healthy infants.

Results

The methodology was validated through simulated motions applied to an uncorrupted dataset and through comparisons with an unmoved reference. Second, we showed that the correction applied to an infant group enabled to improve DTI maps and to increase the reliability of DTI quantification in the immature cortico-spinal tract.

Conclusion

This automated strategy performed reliably on DTI datasets and can be applied to spherical single- and multiple-shell diffusion imaging.

Added: Oct 22, 2015
Article
Vukovic N., Shtyrov Y. Neuroimage. 2014. Vol. 102. No. P2. P. 695-703.

Understanding neurocognitive mechanisms supporting the use of multiple languages is a key question in language science. Recent neuroimaging studies in monolinguals indicated that core language areas in human neocortex together with sensorimotor structures form a highly interactive system underpinning native language comprehension. While the experience of a native speaker promotes the establishment of strong action-perception links in the comprehension network, this may not necessarily be the case for L2 where, as it has been argued, the most a typical L2 speaker may get is a link between an L2 wordform and its L1 translation equivalent. Therefore, we investigated, whether the motor cortex of bilingual subjects shows differential involvement in processing action semantics of native and non-native words. We used high-density EEG to dynamically measure changes in the cortical motor system's activity, indexed by event-related desynchronisation (ERD) of the mu-rhythm, in response to passively reading L1 (German) and L2 (English) action words. Analysis of motor-related EEG oscillations at the sensor level revealed an early (starting ~150ms) and left-lateralised coupling between action and semantics during both L1 and L2 processing. Crucially, source-level activation in the motor areas showed that mu-rhythm ERD, while present for both languages, is significantly stronger for L1 words. This is the first neurophysiological evidence of rapid motor-cortex involvement during L2 action-semantic processing. Our results both strengthen embodied cognition evidence obtained previously in monolinguals and, at the same time, reveal important quantitative differences between L1 and L2 sensorimotor brain activity in language comprehension.

Added: Oct 23, 2014
Article
Kozlova M. A., Kozlov A. Human Physiology. 2014. Vol. 40. No. 2. P. 123-136.

The review considers the roles cortisol (Crt), dehydroepiandrosterone (DHEA), and DHEA sul fate (DHEAS) play in the stress response. Agerelated, sexrelated, and circadian fluctuations in normal conditions and in acute or chronic stress are described for Crt, DHEA, and DHEAS. The main techniques used to estimate the Crt level in the blood, urine, and saliva are described, and approaches to the interpretation of the results discussed. Special attention is paid to Crt assays in anthropological and psychological studies.

Added: Jan 25, 2015
Article
Shmid A., Berezin A., Novopashin M. Annals of Circulation. 2018. No. 3. P. 4-7.

Computer model coupled blood pressure dynamics in magisterial and small arteries networks and its stabilizing effect on heart functioning has been suggested. The Fermi-Pasta-Ulam auto recurrence in the description of the electrical activity of the heart has demonstrated the universal role of the FPU recurrence in the study of distributed dynamical systems. The heart electrical dynamics was described by the coupled Van der Pol differential equations with a time lag, linked with two additively coupled nonlinear differential equations circumscribing the blood pressure dynamics in the networks of magisterial and small arteries. The mathematical model developed by Yuen and Lake for description of the deep wave dynamics within the nonlinear Shrodinger (NSE) equation was used for description of the magisterial arterial blood pressure whereas for small arteries blood pressure dynamics was used the approach elaborated by Zabusky and Kruskal within the framework of the Korteveg de Vries (KdV) equation. The arterial blood pressure dynamics was interpreted as coupled FPU recurrences showing a rich variety of resulting FPU spectra, which were referred to different states of Cardio Vascular System. Synchronous registering of the real ECG and Pulse Wave Fourier dynamic images allowed to unify the characteristic Fourier pictures of the heart electrical activity with the hydrodynamic blood parameters developing in the networks of two types of arteries. The computer study of the suggested model and comparison of its results with the real data proved that the ECG Fourier parameters coupled with the Pulse Wave Fourier parameters form the FPU spectra that increase stability of Cardio Vascular System and can be used for diagnostics as well as for evaluation of the therapeutic arrangements results.

Added: Feb 28, 2018
Article
Peter Meylakhs. Health, Risk and Society. 2011. Vol. 13. No. 3. P. 239-254.

The paper is devoted to analysis of the debates on sex education in the Russian press. ‘Risk narrative structure’ of media articles on sex education was determined. This structure represents a system of mutually constituting elements, which include object of risk, risks themselves, solutions to their prevention, solutions opponents, and type of society these solutions presuppose. It is argued that analysis of risks with the aid of ‘risk narrative structures’ can be a useful development of sociocultural theory of risk, as competing risk narratives can befully grasped only when considered not as discrete claims about different ‘risks’ but as coherent systems of interrelated meanings. On the basis of this structure, competent risk media narratives of proponents and opponents of sex education were reconstructed. In these narratives different definitions of ‘children’ as objects of risk were constructed, and so were types of risks, and types of society. It would be oversimplifying to consider debates on sex education as a battle of ‘enlightened rationality’ against ‘dark irrationality.’ In each risk narrative the solution (introduction or ban of sex education) is a logically following element in the respective risk narrative. While sex education advocates were concerned about negative consequences of children’s sexual behaviour and defence of the ‘civilised society’s moral boundaries, the opposite side was concerned about retaining children’s moral purity and defence of ‘traditional’ moral boundaries.

Added: Mar 8, 2013
Article
Vladimir A. Korshun. Tetrahedron. 2017. Vol. 73. No. 23. P. 3220-3230.

1-Phenylethynylpyrene fluorophore (1-PEPy) has long-wavelength shifted emission and higher photostability compared to pyrene, retaining, however, pyrene's ability to form excimers. Here we report the synthesis of 2'-O-[3(and 4)-(pyren-1-ylethynyl)benzyl]-uridines and their tandem incorporation into deoxyribo- and 2'-O-Me-ribo-oligonucleotide probes. Excimer forming probes of type NN … NNXXNN … NN (X = 2'-O-[meta(or para)-(pyren-1-ylethynyl)-benzyl]uridine) containing two adjacent fluorescent nucleosides within an oligonucleotide are available in four types (meta-meta; para-meta; meta-para; para-para). Both DNA (N = deoxyribonucleotides) and 2'-O-Me-RNA (N = 2'-O-Me-ribo-nucleotides) probes were synthesized and their hybridization with complementary and singly mismatched DNA and RNA was studied. Several probes show a dramatic response of their excimer-to-monomer intensity ratio upon hybridization. Remarkably, most spectacular fluorescence changes were demonstrated for probes with para-meta and meta-para combination within 2'-O-Me-ribo-oligonucleotides. Using excimer forming probes, three natural SNP in Helicobacter pylori 23S RNA gene (A2144G, A2143G, A2143C) and the wild type gene can be distinguished.

Added: Nov 6, 2019
Article
Yasnitsky L., Dumler A. A., Bogdanov K. V. et al. Biomedical Engineering. 2013. Vol. 47. No. 3. P. 160-163.

A neural expert network system for diagnostis and prognosis of cardiovascular diseasas was developed.

Added: Nov 19, 2013
Article
Yasnitsky L., Dumler A. A., Poleshuk A. N. et al. Biology and Medicine. 2015. No. 7.

Objectives: Development of a mathematical model and its implementation as a computer program for diagnostics and prediction of progression of the most widespread cardiovascular diseases; the program is to model different variants of disease progression for an observed patient, and to select individual recommendations for correction of his or her lifestyle, regimen and diet. Methods: Combination of technologies of neural networks and expert systems with a resulting synergistic effect. Results and Conclusion: Investigations of the developed mathematical model showed that it is able to reveal new knowledge which is yet unknown to medical science. In the course of software experiments performed by means of a diagnostics-and-prediction system, we revealed the facts showing that modern medical practice patterns of giving one and the same recommendations to all the cardiac patients without exception (including keeping to a hypocholesteric diet, giving up pernicious habits, limiting coffee and alcoholic drinks, losing weight and limiting intellectual and physical activity) are not always correct. Our investigations showed that some of these recommendations are not just unhealthy, but harmful for a number of patients. The neuro-expert diagnostics-and-prediction system presented in this paper allows doctors to reveal such non-typical patients and to develop individual recommendations especially for them.

Added: Sep 30, 2015
Article
Gerry C., Mickiewicz T., Nikoloskic Z. The Lancet. 2010. Vol. 375. No. 9712.

A recent article in the Lancet, by David Stuckler, Larry King and Martin McKee,

investigated anew the fluctuations in adult male mortality rates that have come to

characterise the so-called post-communist mortality crisis. Adopting a cross-country,

time-series perspective the authors examined how the economic policy strategies of the

1990s impacted upon observed fluctuations in mortality. They conclude that the adoption

of a strategy of rapid (mass) privatisation contributed to the adverse mortality trends. We

subject that finding to closer scrutiny using the same data from which the Stuckler et al

claim stems. We find that their claim that mass privatisation adversely affected male

mortality trends in the post-Communist world does not stand up to closer examination. It

is not supported empirically and is at odds with what we know about both transition in

the post-communist world and about health trends over time in this region.

 

Added: Nov 25, 2015
Article
Soloukhina O., Isaev D., Akinina Y. et al. Stem-, Spraak- en Taalpathologie. 2016. Vol. 21. No. 1. P. 162-164.

There is growing evidence that verbs are more difficult to processes than nouns (Cappa & Perani, 2002) and that verb retrieval is more commonly affected in aphasia compared to nouns (Jonkers & Bastiaanse, 1998). However, existing observations are largely based on naming and semantic judgment tasks. We investigate whether this processing difficulty is modality general. In this study for the first time we directly compare difficulty of comprehension of verbs versus nouns in Russian in individuals with and without aphasia using a novel instrument – a single-word comprehension test presented on a tablet.

Added: Oct 3, 2016
Article
Tonevitsky A., Kononenko O., Mityakina I. et al. Brain Research. 2018. Vol. 1695. P. 78-83.

The endogenous opioid system (EOS) controls the processing of nociceptive stimuli and is a pharmacological target for opioids. Alterations in expression of the EOS genes under neuropathic pain condition may account for low efficacy of opioid drugs. We here examined whether EOS expression patterns are altered in the lumbar spinal cord of the rats with spinal nerve ligation (SNL) as a neuropathic pain model. Effects of the left- and right-side SNL on expression of EOS genes in the ipsi- and contralateral spinal domains were analysed. The SNL-induced changes were complex and different between the genes; between the dorsal and ventral spinal domains; and between the left and right sides of the spinal cord. Prodynorphin (Pdyn) expression was upregulated in the ipsilateral dorsal domains by each the left and right-side SNL, while changes in expression of μ-opioid receptor (Oprm1) and proenkephalin (Penk) genes were dependent on the SNL side. Changes in expression of the Pdyn and κ-opioid receptor (Oprk1) genes were coordinated between the ipsi- and contralateral sides. Withdrawal response thresholds, indicators of mechanical allodynia correlated negatively with Pdyn expression in the right ventral domain after right side SNL. These findings suggest multiple roles of the EOS gene products in spinal sensitization and changes in motor reflexes, which may differ between the left and right sides.

Added: Oct 30, 2018
Article
Timonin S., Shkolnikov V., Jasilionis D. et al. Population Health Metrics. 2016. Vol. 14. No. 29. P. 1-19.

Background

Over the past half century the global tendency for improvements in longevity has been uneven across countries. This has resulted in widening of inter-country disparities in life expectancy. Moreover, the pattern of divergence appears to be driven in part by processes at the level of country groupings defined in geopolitical terms. A systematic quantitative analysis of this phenomenon has not been possible using demographic decomposition approaches as these have not been suitably adapted for this purpose. In this paper we present an elaboration of conventional decomposition techniques to provide a toolkit for analysis of the inter-country variance, and illustrate its use by analyzing trends in life expectancy in developed countries over a 40-year period.

Methods

We analyze trends in the population-weighted variance of life expectancy at birth across 36 developed countries and three country groups over the period 1970–2010. We have modified existing decomposition approaches using the stepwise replacement algorithm to compute age components of changes in the total variance as well as variance between and within groups of Established Market Economies (EME), Central and Eastern Europe (CEE), and the Former Soviet Union (FSU). The method is generally applicable to the decomposition of temporal changes in any aggregate index based on a set of populations.

Results

The divergence in life expectancy between developed countries has generally increased over the study period. This tendency dominated from the beginning of 1970s to the early 2000s, and reversed only after 2005. From 1970 to 2010, the total standard deviation of life expectancy increased from 2.0 to 5.6 years among men and from 1.0 to 3.6 years among women. This was determined by the between-group effects due to polarization between the EME and the FSU. The latter contrast was largely fueled by the long-term health crisis in Russia. With respect to age, the increase in the overall divergence was attributable to between-country differences in mortality changes at ages 15–64 years compared to those aged 65 and older. The within-group variance increased, especially among women. This change was mostly produced by growing mortality differences at ages 65 and older.

Conclusions

From the early 1970s to the mid-2000s, the strong divergence in life expectancy across developed countries was largely determined by the between-group variance and mortality polarization linked to the East–West geopolitical division.

 

Added: Oct 24, 2014
Article
Kobayashi Y., Kulikova Sofya P, Shibato J. et al. World Journal of Biological Chemistry. 2015. Vol. 6. No. 4. P. 389-408.

N-Methyl-D-aspartate receptors (NMDAr) are involved in multiple physiological functions and neuropsychiatric disorders. Dizocilpine (commonly referred to as MK-801) is a well-known non-competitive NMDAr antagonist with psychotomimetic properties. A combination of electrophysiological and molecular analyses reveals not only the synchrony of baseline oscillations by MK-801, but also more importantly new insight into differential gene expressions in the cerebral cortex, midbrain, hippocampus, ventral striatum, amygdala, and hypothalamus regions after acute low-dose (0.08 mg/kg) MK-801 treatment; only the ventral striatum showed increased gene expression at a high dose (0.16 mg/kg) of MK-801. We believe that our present study will contribute in the understanding of the pathogenic mechanisms of neuropsychiatric disorders.

Added: Oct 22, 2015
Article
Kadurin A., Nikolenko S. I., Khrabrov K. et al. Molecular Pharmaceutics. 2017. Vol. 14. No. 9. P. 3098-3104.

Deep generative adversarial networks (GANs) are the emerging technology in drug discovery and biomarker development. In our recent work, we demonstrated a proof-of-concept of implementing deep generative adversarial autoencoder (AAE) to identify new molecular fingerprints with predefined anticancer properties. Another popular generative model is the variational autoencoder (VAE), which is based on deep neural architectures. In this work, we developed an advanced AAE model for molecular feature extraction problems, and demonstrated its advantages compared to VAE in terms of (a) adjustability in generating molecular fingerprints; (b) capacity of processing very large molecular data sets; and (c) efficiency in unsupervised pretraining for regression model. Our results suggest that the proposed AAE model significantly enhances the capacity and efficiency of development of the new molecules with specific anticancer properties using the deep generative models.

Added: Mar 14, 2018
Article
Nazarova M., Kulikova S., Konovalov R. N. et al. Cerebrovascular Diseases. 2016. Vol. 41 (Suppl. 1). P. 74-74.
Reliable assessment of the motor system at the individual level is crusial for developing an individual rehabilitation plan in stroke patients. The aim of the study was to analyze corticospinal tract (CST) integrity and the state of the unaffected hemisphere (UH) in chronic ischemic stroke patients with different hand motor outcome using methods of diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS).
Added: Feb 17, 2017
Article
Tonevitsky A. G., Maltseva D. V., Abbasi A. et al. BMC Physiology. 2013. Vol. 13.

Background

MiRNAs are essential mediators of many biological processes. The aim of this study was to investigate the dynamics of miRNA-mRNA regulatory networks during exercise and the subsequent recovery period.

Results

Here we monitored the transcriptome changes using microarray analysis of the whole blood of eight highly trained athletes before and after 30 min of moderate exercise followed by 30 min and 60 min of recovery period. We combined expression profiling and bioinformatics and analysed metabolic pathways enriched with differentially expressed mRNAs and mRNAs which are known to be validated targets of differentially expressed miRNAs. Finally we revealed four dynamically regulated networks comprising differentially expressed miRNAs and their known target mRNAs with anti-correlated expression profiles over time. The data suggest that hsa-miR-21-5p regulated TGFBR3, PDGFD and PPM1L mRNAs. Hsa-miR-24-2-5p was likely to be responsible for MYC andKCNJ2 genes and hsa-miR-27a-5p for ST3GAL6. The targets of hsa-miR-181a-5p included ROPN1L and SLC37A3. All these mRNAs are involved in processes highly relevant to exercise response, including immune function, apoptosis, membrane traffic of proteins and transcription regulation.

Conclusions

We have identified metabolic pathways involved in response to exercise and revealed four miRNA-mRNA networks dynamically regulated following exercise. This work is the first study to monitor miRNAs and mRNAs in parallel into the recovery period. The results provide a novel insight into the regulatory role of miRNAs in stress adaptation.

Added: Oct 30, 2015
Article
Assecondi S., Vanderperren K., Novitskiy N. et al. Clinical Neurophysiology. 2010. Vol. 121. P. 672-685.
This work investigates the influence of the static magnetic field of the MR-scanner onERPs extracted from simultaneous EEG–fMRI recordings. The quality of the ERPs after BallistoCardioGraphic (BCG) artifact removal, as well as the reproducibility of the waveforms in different environments is investigated. We consider a Detection, a Go–Nogo and a Motor task, eliciting peaks that differ in amplitude, latency and scalp topography, repeated in two situations: outside the scanner room (0 T) and inside the MR-scanner but without gradients (3 T). The BCG artifact is removed by means of three techniques: the Average Artifact Subtraction (AAS) method, the Optimal Basis Set (OBS) method and the Canonical Correlation Analysis (CCA) approach. 

The performance of the three methods depends on the amount of averaged trials. Moreover, differences are found on both amplitude and latency of ERP components recorded in two environments (0 T vs 3 T). We showed that, while ERPs can be extracted from simultaneous EEG–fMRI data at 3 T, the static magnetic field might affect the physiological processes under investigation.The reproducibility of the ERPs in different recording environments (0 T vs 3 T) is a relevant issue that deserves further investigation to clarify the equivalence of cognitive processes in both behavioral and imaging studies.

Added: Jul 10, 2015
Article
Novitski Nikolai, Alho K., Korzyukov O. et al. Neuroimage. 2001. Vol. 14. P. 244-251.

The processing of sound changes and involuntary attention to them has been widely studied with event-related brain potentials (ERPs). Recently, functional magnetic resonance imaging (fMRI) has been applied to determine the neural mechanisms of involuntary attention and the sources of the corresponding ERP components. The gradient-coil switching noise from the MRI scanner, however, is a challenge to any experimental design using auditory stimuli. In the present study, the effects of MRI noise on ERPs associated with preattentive processing of sound changes and involuntary switching of attention to them were investigated. Auditory stimuli consisted of frequently presented “standard” sounds, infrequent, slightly higher “deviant” sounds, and infrequent natural “novel” sounds. The standard and deviant sounds were either sinusoidal tones or musical chords, in separate stimulus sequences. The mismatch negativity (MMN) ERP associated with preattentive sound change detection was elicited by the deviant and novel sounds and was not affected by the prerecorded background MRI noise (in comparison with the condition with no background noise). The succeeding positive P3a ERP responses associated with involuntary attention switching elicited by novel sounds were also not affected by the MRI noise. However, in ERPs to standard tones and chords, the P1, N1, and P2 peak latencies were significantly prolonged by the MRI noise. Moreover, the amplitude of the subsequent “exogenous” N2 to the standard sounds was significantly attenuated by the presence of MRI noise. In conclusion, the present results suggest that in fMRI the background noise does not interfere with the imaging of auditory processing related to involuntary attention.

Added: Jul 10, 2015
Article
Amirkhanian Y., Kelly J., Takacs J. et al. AIDS. 2015. Vol. 29. No. 5. P. 583-593.
OBJECTIVE:

To test a novel social network HIV risk-reduction intervention for MSM in Russia and Hungary, where same-sex behavior is stigmatized and men may best be reached through their social network connections.

DESIGN:

A two-arm trial with 18 sociocentric networks of MSM randomized to the social network intervention or standard HIV/STD testing/counseling.

SETTING:

St. Petersburg, Russia and Budapest, Hungary.

PARTICIPANTS:

Eighteen 'seeds' from community venues invited the participation of their MSM friends who, in turn, invited their own MSM friends into the study, a process that continued outward until eighteen three-ring sociocentric networks (mean size = 35 members, n = 626) were recruited.

INTERVENTION:

Empirically identified network leaders were trained and guided to convey HIV prevention advice to other network members.

MAIN OUTCOME AND MEASURES:

Changes in sexual behavior from baseline to 3-month and 12-month follow-up, with composite HIV/STD incidence, measured at 12 months to corroborate behavior changes.

RESULTS:

There were significant reductions between baseline, first follow-up, and second follow-up in the intervention versus comparison arm for proportion of men engaging in any unprotected anal intercourse (UAI) (P = 0.04); UAI with a nonmain partner (P = 0.04); and UAI with multiple partners (P = 0.002). The mean percentage of unprotected anal intercourse acts significantly declined (P = 0.001), as well as the mean number of UAI acts among men who initially had multiple partners (P = 0.05). Biological HIV/STD incidence was 15% in comparison condition networks and 9% in intervention condition networks.

CONCLUSION:

Even where same-sex behavior is stigmatized, it is possible to reach MSM and deliver HIV prevention through their social networks.

Added: Sep 12, 2017
Article
Novitski Nikolai, Anourova I., Martikauppi S. et al. Neuroimage. 2003. Vol. 20. No. 2. P. 1320-1328.

The effects of functional magnetic resonance imaging (fMRI) acoustic noise were investigated on the parameters of event-related responses (ERPs) elicited during auditory matching-to-sample location and pitch working memory tasks. Stimuli were tones with varying location (left or right) and frequency (high or low). Subjects were instructed to memorize and compare either the locations or frequencies of the stimuli with each other. Tape-recorded fMRI acoustic noise was presented in half of the experimental blocks. The fMRI noise considerably enhanced the P1 component, reduced the amplitude and increased the latency of the N1, shortened the latency of the N2, and enhanced the amplitude of the P3 in both tasks. The N1 amplitude was higher in the location than pitch task in both noise and no-noise blocks, whereas the task-related N1 latency difference was present in the no-noise blocks only. Although the task-related differences between spatial and nonspatial auditory responses were partially preserved in noise, the finding that the acoustic gradient noise accompanying functional MR imaging modulated the auditory ERPs implies that the noise may confound the results of auditory fMRI experiments especially when studying higher cognitive processing

Added: Jul 10, 2015