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1.
Nature ; 621(7980): 716-722, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37758891

ABSTRACT

Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.

2.
Sovrem Tekhnologii Med ; 12(3): 12-23, 2021.
Article in English | MEDLINE | ID: mdl-34795975

ABSTRACT

The potential mechanisms of bronchial asthma (BA) negative modification under the influence of obesity are currently being actively studied. However, at present, the effect of nutritional status on bronchial obstruction in children with BA cannot be considered established. In this regard, the purpose of this work was to study the relationship of spirometric parameters reflecting bronchial patency with nutritional status in children with asthma. MATERIALS AND METHODS: The study involved 54 patients with BA at the age of 8 to 17 years, 33 boys and 21 girls with different nutritional status. Assessment of nutritional status was carried out with the calculation of body mass index (BMI), relative body mass index (RBMI), and determination of body fat (% BF). Spirogram parameters were evaluated, including forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, maximum expiratory flow at the point of 25% loop flow-volume (MEF 25). RESULTS: Among the children examined, taking into account the BMI Z-score, 9.3% (5/54) had low body weight (group 1), 33% (18/54) had normal body weight (group 2), 31.5% (17/54) overweight (group 3), 25.9% (14/54) obesity (group 4). As the body weight increased, a statistically significant decrease in the FEV1/FVC ratio was observed, amounting to 84.6 [79.3; 90.0], 79.4 [76.6; 82.2], 74.6 [71.7; 77.5], 70.2 [67.0; 73.4]%, respectively, p=0.003; as well as a decrease in MEF 25 (% pred.), which amounted, respectively, to 95.6 [76.1; 115.2], 81.7 [71.4; 92.0], 56.3 [45.7; 66.9], and 48.4 [36.7; 60.1]%, p=0.003. A statistically significant negative relationship was found between indicators of nutritional status, including BMI, RBMI, % BF, and spirometry parameters reflecting bronchial patency, including FEV1/FVC ratio and MEF 25 (% pred.); all p<0.01. CONCLUSIONS: Overweight and obesity in children with BA, estimated both by calculated methods with determination of BMI and RBMI and direct determination of body fat content, are accompanied by a statistically significant decrease in bronchial patency.


Subject(s)
Asthma , Pediatric Obesity , Adolescent , Asthma/complications , Child , Female , Forced Expiratory Volume , Humans , Male , Nutritional Status , Pediatric Obesity/complications , Spirometry
3.
Nature ; 592(7852): 35-42, 2021 04.
Article in English | MEDLINE | ID: mdl-33790445

ABSTRACT

The photon-the quantum excitation of the electromagnetic field-is massless but carries momentum. A photon can therefore exert a force on an object upon collision1. Slowing the translational motion of atoms and ions by application of such a force2,3, known as laser cooling, was first demonstrated 40 years ago4,5. It revolutionized atomic physics over the following decades6-8, and it is now a workhorse in many fields, including studies on quantum degenerate gases, quantum information, atomic clocks and tests of fundamental physics. However, this technique has not yet been applied to antimatter. Here we demonstrate laser cooling of antihydrogen9, the antimatter atom consisting of an antiproton and a positron. By exciting the 1S-2P transition in antihydrogen with pulsed, narrow-linewidth, Lyman-α laser radiation10,11, we Doppler-cool a sample of magnetically trapped antihydrogen. Although we apply laser cooling in only one dimension, the trap couples the longitudinal and transverse motions of the anti-atoms, leading to cooling in all three dimensions. We observe a reduction in the median transverse energy by more than an order of magnitude-with a substantial fraction of the anti-atoms attaining submicroelectronvolt transverse kinetic energies. We also report the observation of the laser-driven 1S-2S transition in samples of laser-cooled antihydrogen atoms. The observed spectral line is approximately four times narrower than that obtained without laser cooling. The demonstration of laser cooling and its immediate application has far-reaching implications for antimatter studies. A more localized, denser and colder sample of antihydrogen will drastically improve spectroscopic11-13 and gravitational14 studies of antihydrogen in ongoing experiments. Furthermore, the demonstrated ability to manipulate the motion of antimatter atoms by laser light will potentially provide ground-breaking opportunities for future experiments, such as anti-atomic fountains, anti-atom interferometry and the creation of antimatter molecules.

4.
Nature ; 561(7722): 211-215, 2018 09.
Article in English | MEDLINE | ID: mdl-30135588

ABSTRACT

In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum1,2. The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. Since then, studies involving the Lyman-α line-the 1S-2P transition at a wavelength of 121.6 nanometres-have played an important part in physics and astronomy, as one of the most fundamental atomic transitions in the Universe. For example, this transition has long been used by astronomers studying the intergalactic medium and testing cosmological models via the so-called 'Lyman-α forest'3 of absorption lines at different redshifts. Here we report the observation of the Lyman-α transition in the antihydrogen atom, the antimatter counterpart of hydrogen. Using narrow-line-width, nanosecond-pulsed laser radiation, the 1S-2P transition was excited in magnetically trapped antihydrogen. The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 ± 0.12 gigahertz (1σ uncertainty) and agrees with the prediction for hydrogen to a precision of 5 × 10-8. Comparisons of the properties of antihydrogen with those of its well-studied matter equivalent allow precision tests of fundamental symmetries between matter and antimatter. Alongside the ground-state hyperfine4,5 and 1S-2S transitions6,7 recently observed in antihydrogen, the Lyman-α transition will permit laser cooling of antihydrogen8,9, thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements10. In addition to the observation of this fundamental transition, this work represents both a decisive technological step towards laser cooling of antihydrogen, and the extension of antimatter spectroscopy to quantum states possessing orbital angular momentum.

5.
Nature ; 557(7703): 71-75, 2018 05.
Article in English | MEDLINE | ID: mdl-29618820

ABSTRACT

In 1928, Dirac published an equation 1 that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was confirmed with the discovery of the positron 2 (or anti-electron) by Anderson in 1932, but it is still unknown why matter, rather than antimatter, survived after the Big Bang. As a result, experimental studies of antimatter3-7, including tests of fundamental symmetries such as charge-parity and charge-parity-time, and searches for evidence of primordial antimatter, such as antihelium nuclei, have high priority in contemporary physics research. The fundamental role of the hydrogen atom in the evolution of the Universe and in the historical development of our understanding of quantum physics makes its antimatter counterpart-the antihydrogen atom-of particular interest. Current standard-model physics requires that hydrogen and antihydrogen have the same energy levels and spectral lines. The laser-driven 1S-2S transition was recently observed 8 in antihydrogen. Here we characterize one of the hyperfine components of this transition using magnetically trapped atoms of antihydrogen and compare it to model calculations for hydrogen in our apparatus. We find that the shape of the spectral line agrees very well with that expected for hydrogen and that the resonance frequency agrees with that in hydrogen to about 5 kilohertz out of 2.5 × 1015 hertz. This is consistent with charge-parity-time invariance at a relative precision of 2 × 10-12-two orders of magnitude more precise than the previous determination 8 -corresponding to an absolute energy sensitivity of 2 × 10-20 GeV.

6.
Article in Russian | MEDLINE | ID: mdl-25713871

ABSTRACT

Electrical brain activity accompanying various forms of behavior was studied in 11-day-old pied flycatcher nestlings. Wavelet analysis of EEG, recorded from symmetrical areas of caudomedial nidopallium (higher avian auditory center) during rest, passive and active wakefulness and movements showed that the major rhythmical EEG component was confined to low-frequency range in all four states. The significant difference from other states was observed only during movements: spectral power in the range of 1-3 Hz decreased while that in the range of 5-20 Hz--increased. The range of 3-5 Hz revealed, in all functional states, the interhemispheric asymmetry of spectral power that could be due to asymmetrical embryonic development of avian visual projections. Active wakefulness and movements were characterized by high positive correlations between spectral power in right and left hemispheres. During rest this correlation was negative. The correlation values during passive wakefulness and rest were rather low that could indicate disintegration of neural connections.


Subject(s)
Cerebrum/physiology , Movement/physiology , Rest/physiology , Songbirds/physiology , Wakefulness/physiology , Animals , Animals, Newborn , Cerebrum/anatomy & histology , Electroencephalography , Functional Laterality
7.
Article in Russian | MEDLINE | ID: mdl-23530451

ABSTRACT

It is known that sleep spindles are produced by thalamo-cortical system spontaneously during the slow-wave sleep; pathological processes in thalamo-cortical network might cause absence epilepsy. The aim of this study was to examine age-dependent changes in time-frequency structure of sleep spindles in parallel to a progressive increase in amount of absence seizures in WAG/Rij rat model. EEG was consistently recorded at the age of 5, 7 and 9 months by means of epidural electrodes implanted in the frontal cortex. Continuous wavelet transform was used for automatic identification and further time-frequency analysis of sleep spindles in EEG. It was found that the mean duration of epileptic discharges and total duration of epileptic activity increased with age, whereas the length of sleep spindles decreased. Mean frequency of oscillations within a spindle was used as a criterion for dividing sleep spindles in three categories: "slow" (9.3 Hz), "tr ansitional" (11.4 Hz) and "fast" (13.5 Hz). "Slow" and "transitional" spindles in 5-months animals displayed an increase in frequency from the beginning towards the end. It was shown that the higher incidence of epilepsy corresponded to the lower duration of sleep spindles (all types). Mean frequency of "transitional" and "fast" spindles was higher in rats with more intensive epileptic discharges. In general, high epileptic activity in WAG/Rij rats corresponded to the most substantial changes within "transitional" spindles, whereas changes within slow and fast spindles were moderate.


Subject(s)
Epilepsy, Absence/physiopathology , Sleep Stages , Age Factors , Animals , Cerebral Cortex/physiopathology , Electroencephalography , Epilepsy, Absence/genetics , Genetic Predisposition to Disease , Male , Rats , Rats, Inbred Strains , Thalamus/physiopathology
8.
J Phys Chem A ; 113(11): 2383-6, 2009 Mar 19.
Article in English | MEDLINE | ID: mdl-19226115

ABSTRACT

We reinvestigated the 2 + 1 REMPI Q-branch spectrum of the a''1Sigma(g)+-X1Sigma(g)+ system of N2 at around 202 nm in a Doppler-free configuration with counterpropagating laser beams. Highly accurate absolute calibrations were performed using either an I2 reference standard or a frequency comb reference laser. The observed rotational series shows a clear effect of a perturbation in terms of an anticrossing located at J = 26. In addition to the improved set of molecular constants for the a''1Sigma(g)+ state, we tentatively assign the perturber state to be the 1Sigma(g)+(II) state of N2.

9.
Phys Rev Lett ; 101(22): 223001, 2008 Nov 28.
Article in English | MEDLINE | ID: mdl-19113480

ABSTRACT

Two distinct high-accuracy laboratory spectroscopic investigations of the H2 molecule are reported. Anchor lines in the EF1Sigmag+-X1Sigmag+ system are calibrated by two-photon deep-UV Doppler-free spectroscopy, while independent Fourier-transform spectroscopic measurements are performed that yield accurate spacings in the B1Sigmau+-EF1Sigmag+ and I1Pig-C1Piu systems. From combination differences accurate transition wavelengths for the B-X Lyman and the C-X Werner lines can be determined with accuracies better than approximately 5 x 10(-9), representing a major improvement over existing values. This metrology provides a practically exact database to extract a possible variation of the proton-to-electron mass ratio based on H2 lines in high-redshift objects. Moreover, it forms a rationale for equipping a future class of telescopes, carrying 30-40 m dishes, with novel spectrometers of higher resolving powers.

10.
Vestn Oftalmol ; 119(5): 37-40, 2003.
Article in Russian | MEDLINE | ID: mdl-14598494

ABSTRACT

A diagnostic tools' set was worked out for the digital analysis of eye-fundus images; it comprises a retinophot and a digital camera adapted to it as well as a computer system and a special soft. A new mathematical model of a fragment of the ocular main microcirculation vessel and the below related global diagnostic parameters of the vascular system were elaborated: mean diameter, deviation from linearity, image acutance, fluctuations' amplitude for thickness and route, and sinuosity of thickness and route. The system of eye-fundus image processing provides for precising a nature of changes in vascular thickness along the route and for assessing the local diameter by using the vascular profile; it can also be used for determining the angle of vessels' branching. A set of expert diagnostic etalons was set up for vascular pathologies of the eye fundus and an appropriate database was created. The advantages of the designed system are: the possibility to use it comprehensively in clinical practice, less time needed to make and to analyze the eye-fundus images, a higher accuracy in determining the local vascular diameter, the possibility to perform simultaneously an analysis of diagnostic signs of retinal vessels on the basis of using a radically new approach towards assessing the vascular system ("tracing-type isolation of segments"), a higher diagnostic efficiency, the possibility to perform the differential diagnosis and the capability of preserving data without any limitations by volume and store duration time.


Subject(s)
Fundus Oculi , Image Processing, Computer-Assisted , Retinal Diseases/diagnosis , Retinal Vessels , Databases as Topic , Diabetic Retinopathy/diagnosis , Diagnosis, Differential , Eye/blood supply , Fluorescein Angiography , Humans , Microcirculation , Models, Theoretical , Ophthalmoscopy , Software
11.
Biofizika ; 48(2): 374-9, 2003.
Article in Russian | MEDLINE | ID: mdl-12723366

ABSTRACT

The effect of geomagnetic disturbances on the intrauterine condition of the fetus in high latitudes was studied by comparing the index of fetus condition (IFC) with the heliogeophysical indices (planetary Kp index and Dst variation index). The functional state of fetus at late terms of pregnancy was assessed by the method of cardiomonitoring. The data of fetal cardiomonitoring were processed by the method of Prof. Demidov by calculating the integral IFC using a computer program. It was found that the variations in maximum IFC values (approximately 15% of the total number of cases) coincide with seasonal variations in geomagnetic disturbances. The maximum values of IFC were observed at the equinox (March-April-May, October-November), and the minimum values were registered in the period of the solstice. A comparison of IFC values with the indices of geomagnetic disturbances indicated that the IFC value was maximum in the periods of either the greatest weakening of geomagnetic activity or maximum disturbances.


Subject(s)
Electromagnetic Fields , Fetus/physiopathology , Solar Activity , Arctic Regions , Cardiotocography , Data Interpretation, Statistical , Female , Heart Rate , Humans , Pregnancy
12.
Analyst ; 124(7): 1027-33, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10736860

ABSTRACT

The enhanced microdialysis relative recovery (RR) of some hydrophobic tricyclic drugs (imipramine, desipramine, amitriptyline, carbamazepine and promethazine) is discussed. Enhanced RR was achieved by including a binding agent [beta-cyclodextrin (beta-CD) or 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD)] in the microdialysis perfusion fluid to form inclusion complexes with the drugs, which increases the analyte flux through the membrane material. The maximum effect of the RR increase for all the drugs studied was observed using a commercially available polycarbonate-polyether (PC) membrane. With a 4 mm PC membrane and 4.41 mmol l-1 (0.5% w/v) beta-CD included in the microdialysis perfusion fluid (0.9% saline, pH 7.4) at a flow rate of 0.5 microliter min-1, RR enhancements over controls were as follows: carbamazepine 136, imipramine 268, desipramine 298, amitriptyline 634, and promethazine 987%. Increasing beta-CD [up to 17.63 mmol l-1 (2% w/v)] or HP-beta-CD [up to 32.5 mmol l-1 (5% w/v)] concentration in the microdialysis perfusion fluid enhanced carbamazepine RR three (beta-CD) to four (HP-beta-CD) times compared to controls through PC microdialysis membranes. The PC membrane gave enhanced RR values that were twice those for cuprophan or AN-69 membranes. Enhanced RR with cyclodextrins was successfully applied to sampling from a protein solution containing desipramine in a 4% w/v bovine serum albumin solution. These results suggest that addition of cyclodextrins to microdialysis perfusion fluids may be used to increase microdialysis RR during blood sampling.


Subject(s)
Antidepressive Agents, Tricyclic/analysis , Extracellular Space/chemistry , Chromatography, High Pressure Liquid , Cyclodextrins , Humans , Microdialysis
13.
Anal Chem ; 71(7): 1257-64, 1999 Apr 01.
Article in English | MEDLINE | ID: mdl-21662949

ABSTRACT

A novel approach to increase microdialysis recovery (extraction efficiency, E(d)) by facilitated transport through the microdialysis membrane is described. This new approach facilitates mass transport into the microdialysis probe by inclusion of a complexation agent in the microdialysis perfusion fluid. In these studies, ß-cyclodextrin (ß-CD) (0.25-2.0 w/v%) was included in the microdialysis perfusion fluid consisting of a Ringer's solution (155 mM NaCl, 4.0 mM KCl, 2.4 mM CaCl(2)). ß-CD forms known inclusion complexes with 2-(4-isobutylphenyl)propionic acid (ibuprofen). Ibuprofen E(d) was significantly enhanced (1.5-2.0 times) through different microdialysis membrane materials. The effect of microdialysis membrane material (polycarbonate/polyether, AN-69, cuprophan), pH, ß-CD concentration, and ibuprofen concentration on the E(d) was examined. Only the polycarbonate/polyether membrane was able to give an E(d) greater than 100%. In general, a maximum increase in E(d) was found when 0.5 w/v% ß-CD was included in the perfusion fluid. Variations in the ibuprofen concentration external to the microdialysis probe did not significantly change E(d) when 0.5 w/v% ß-CD was included in the perfusion fluid. In contrast to the ibuprofen data, ß-CD inclusion in the microdialysis perfusion fluid did not affect antipyrine E(d). Antipyrine does not form known inclusion complexes with ß-CD. The ability of ß-CD to increase microdialysis E(d) is explained by facilitated transport.

14.
Lik Sprava ; (2): 84-8, 1992 Feb.
Article in Russian | MEDLINE | ID: mdl-1441345

ABSTRACT

Results of clinico-functional examination of workers of metallurgical plants confirmed early development and severe course of chronic bronchitis in this category of workers. The polyetiological aspect of chronic bronchitis is suggested. Changes of the pleura and pneumosclerosis which often accompany chronic bronchitis impede the differential diagnosis with interstitial form of pneumoconiosis. Diagnostic criteria of chronic bronchitis in metallurgists should be determined with consideration of concrete working conditions, endogenous factors of risk in the development of the disease and possible variants of the course.


Subject(s)
Bronchitis/diagnosis , Metallurgy , Occupational Diseases/diagnosis , Bronchitis/etiology , Chronic Disease , Humans , Male , Occupational Diseases/etiology , Occupational Exposure/adverse effects , Ukraine
15.
Vrach Delo ; (4): 78-80, 1991 Apr.
Article in Russian | MEDLINE | ID: mdl-2063577

ABSTRACT

It was established that patients with chronic obstructive bronchitis widely suffered of chronic pancreatitis, diffuse pancreatofibrosis, hypertensive types of disorders of the main sphincters of the biliary system. It was found that solizyme increases the efficacy of complex therapy of the patients with chronic obstructive bronchitis in the presence of diffuse pancreatofibrosis. This improves the indices of bronchial patency and reduces allergization of the body.


Subject(s)
Biliary Dyskinesia/therapy , Bronchitis/therapy , Pancreatitis/therapy , Adult , Biliary Dyskinesia/diagnosis , Bronchitis/diagnosis , Chronic Disease , Combined Modality Therapy , Drug Therapy, Combination , Female , Fibrosis/diagnosis , Fibrosis/therapy , Humans , Liver/physiopathology , Male , Middle Aged , Pancreas/physiopathology , Pancreatitis/diagnosis
16.
Vrach Delo ; (9): 78-9, 1990 Sep.
Article in Russian | MEDLINE | ID: mdl-2284779

ABSTRACT

The extension and pathogenetic role of pleural changes in the development of unspecific chronic pulmonary diseases in 146 workers of different professional groups suffering of chronic bronchitis, were investigated. Ultrasonography and roentgenography were used. The functional state of the lungs was evaluated by means of spirographic and radiological methods. It is concluded that pleural changes are an endogenous risk factor in the development of chronic unspecific pulmonary diseases.


Subject(s)
Bronchitis/complications , Pleurisy/etiology , Bronchitis/diagnosis , Chronic Disease , Humans , Metallurgy , Pleurisy/diagnosis , Pneumoconiosis/complications , Pneumoconiosis/diagnosis , Tissue Adhesions/diagnosis , Tissue Adhesions/etiology , Ukraine
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