Instantaneous Radio Spectra of Giant Pulses from the Crab Pulsar from Decimeter to Decameter Wavelengths

The results of simultaneous multifrequency observations of giant radio pulses from the Crab pulsar, PSR B0531+21, at 23, 111, and 600 MHz are presented and analyzed. Giant pulses were detected at a frequency as low as 23 MHz for the first time. Of the 45 giant pulses detected at 23 MHz, 12 were identified with counterparts observed simultaneously at 600 MHz. Of the 128 giant pulses detected at 111 MHz, 21 were identified with counterparts observed simultaneously at 600 MHz. The spectral indices for the power-law frequency dependence of the giant-pulse energies are from -3.1 to -1.6. The mean spectral index is -2.7 +/- 0.1 and is the same for both frequency combinations (600-111 MHz and 600-23 MHz). The large scatter in the spectral indices of the individual pulses and the large number of unidentified giant pulses suggest that the spectra of the individual giant pulses do not actually follow a simple power law. The observed shapes of the giant pulses at all three frequencies are determined by scattering on interstellar plasma irregularities. The scatter broadening of the pulses and its frequency dependence were determined as tau_sc=20*(f/100)^(-3.5 +/- 0.1) ms, where the frequency f is in MHz.Comment: 13 pages, 1 figure, 1 table (originally published in Russian in Astronomicheskii Zhurnal, 2006, vol. 83, No. 7, pp. 630-637), translated by Georgii Rudnitski

Research of the Leukocytes Segmentation Method in the Blood Cells Recognition Systems

The paper proposed a method of segmentation of leukocytes from the blood and bone marrow samples. A study of the accuracy characteristics of the method is carried out. The techniques of watersheds and the distances transformation were used as the basis of our segmentation method to achieve optimal segmentation of leukocyte. Proposed method was successfully embedded in the system of automatic recognition of white blood cells for classification of blood cells. Keywords: white blood cells segmentation, cells recognition, watershed method, distance transformation method, acute leukemia

Rapid Mass Spectrometric Study of a Supercritical CO2-extract from Woody Liana Schisandra chinensis by HPLC-SPD-ESI-MS/MS

Woody liana Schisandra chinensis contains valuable lignans, which are phenylpropanoids with valuable biological activity. Among green and selective extraction methods, supercritical carbon dioxide (SC-CO2) was shown to be the method of choice for the recovery of these naturally occurring compounds. Carbon dioxide (CO2) was the solvent with the flow rate (10−25 g/min) with 2% ethanol as co-solvent. In this piece of work operative parameters and working conditions were optimized by experimenting with different pressures (200–400 bars) and temperatures (40–60 °C). The extraction time varied from 60 to 120 min. HPLC-SPD-ESI -MS/MS techniques were applied to detect target analytes. Twenty-six different lignans were identified in the S. chinensis SC-CO2 extracts

Detection of decametre-wavelength pulsed radio emission of 40 known pulsars

International audienceThe study of pulsars at the lowest radio frequencies observable from the ground (10-30 MHz) is complicated by strong interstellar (dispersion, scattering) and ionospheric (scintillation, refraction) propagation effects, as well as intense Galactic background noise and interference. However, it permits us to measure interstellar plasma parameters (the effects of which increase by a power of two to >4 times the wavelength), the spectrum and the pulse profile at low frequencies more accurately. Up to now, only ˜10 pulsars have been successfully detected at these frequencies. The recent upgrade of the receivers at the Ukrainian T-shaped Radio telescope, second modification (UTR-2) has increased its sensitivity and motivated a new search for pulsed radio emissions. In this work we carried out a survey of known pulsars with declination above -10°, period >0.1 s and dispersion measure (DM) < 30 pc cm-3, i.e. a sample of 74 sources. Our goal was either to detect pulsars not recorded before in the decametre range or to identify factors that prevent their detection. As a result, we have detected the radio emission of 40 pulsars, i.e. 55 per cent of the observed sample. For 30 of them, this was a first detection at these frequencies. Parameters of their average profiles have been calculated, including the intrinsic widening of the pulse (not due to interstellar scattering) with decreasing frequency. Furthermore, two pulsars beyond the selected DM (B0138+59 with DM ≈ 35 pc cm-3 and B0525+21 with DM ≈51 pc cm-3) were also detected. Our results indicate that there is still room to detect new transient and pulsed sources with low-frequency observations

Glycyrrhetinic acid and its derivatives as inhibitors of poly(ADP-ribose)polymerases 1 and 2, apurinic/apyrimidinic endonuclease 1 and DNA polymerase β

Aim. For strengthening the efficiency of monofunctional alkylating antineoplastic drugs it is important to lower the capacity of base excision repair (BER) system which corrects the majority of DNA damages caused by these reagents. The objective was to create inhibitors of the key BER enzymes (PARP1, PARP2, DNA polymerase β, and APE1) by the directed modification of glycyrrhetinic acid (GA). Methods. Amides of GA were produced from the GA acetate by formation of the corresponding acyl chloride, amidation with the appropriate amine and subsequent deacylation. Small library of 2-cyano substituted derivatives of GA methyl esters was obtained by the structural modification of GA framework and carboxylic acid group. The inhibitory capacity of the compounds was estimated by comparison of the enzyme activities in specific tests in the presence of compounds versus their absence. Results. None of tested compounds inhibits PARP1 significantly. Unmodified GA and its morpholinic derivative were shown to be weak inhibitors of PARP2. The derivatives of GA containing keto-group in 11 triterpene framework were shown to be moderate inhibitors of pol β. Compound 3, containing 12-oxo-9(11)-en moiety in the ring C, was shown to be a single inhibitor of APE1 among all compounds studied. Conclusions. The class of GA derivatives, selective pol β inhibitors, was found out. The selective inhibitor of APE1 and weak selective inhibitor of PARP2 were also revealed

CATALYTIC PHOTOMETRIC DETERMINATION OF NITRATE IN NATURE WATER USING STEPWISE INJECTION ANALYSIS

A new express technique for the kinetic catalytic photometric determination of nitrate by stepwise injection analysis is introduced. The detection is based on the catalytic effect of nitrite on the oxidation of ethylendiaminetetreaacetat manganese (II) to red ethylendiaminetetreaacetat manganese (III) by hydrogen peroxide. Nitrate was preliminary reduced to nitrite using copperised cadmium reductor column. The measurement of the red color absorbance was monitored at 520 nm wavelength. Determined the reliable working concentration range to be 0.1 – 5 mg/dm3 with 3σ detection limit of 0.02 mg/dm3. The relative random measurement error of the technique does not exceed 15 %. The advantages and disadvantages of the copperised cadmium reductor location in the hydraulic circuits of the flow-injection and stepwise injection analysis methods were considered. Reviewed the copperised cadmium reductor placing using the stepwise injection analysis method presented in the literature and offered another alternative of placing. The proposed technique was tested by the added – found method and referent method with satisfactory results. The major advantages of this technique are simplicity, selectivity and economy of reagents. The technique can be used to automatically determine nitrate in continuous mode at a rate of 12 samples per hour, and in the mode with a delay between samples. The technique could be applied successfully for the nitrate determination in nature fresh and salt waters.Key words: nitrate, photometric determination, catalytic reaction, nature water, stepwise injection analysis(Russian)DOI:http://dx.doi.org/10.15826/analitika.2015.19.1.012 V.M. Zakharenko1, Iu.S. Khudiakov1, A.V. Mozzhukhin1, A.L. Moskvin21ZAO NPO Granit-NEMP, Saint Petersburg, Russian Federation2Saint Petersburg State University, Saint Petersburg, Russian Federatio

Catalytic photometric determination of nitrate in nature water using stepwise injection analysis

Разработана кинетическая фотометрическая методика экспрессного определения нитрат-ионов в природных пресных и соленых водах с использованием циклического инжекционного анализа. Методика основана на каталитическом влиянии нитрит-ионов на реакцию окисления этилендиаминтетраацетата марганца (II) пероксидом водорода после предварительного восстановления нитрат-ионов до нитрит-ионов при помощи омедненного Cd-редуктора. В результате реакции образуется окрашенное соединение - этилендиаминтетраацетат марганца (III). Измерение оптической плотности раствора проводили при длине волны 520 нм. Диапазон определяемых концентраций 0.1-5 мг/л. Предел обнаружения 0.02 мг/л. Относительная случайная погрешность определения не превышает 15 %. Рассмотрены преимущества и недостатки расположения омедненного Cd-редуктора в гидравлических схемах проточно-инжекционного и циклического инжекционного анализов. Рассмотрен представленный в литературе вариант расположения омедненного Cd-редуктора в методике, реализованной в циклическом инжекционном анализе, и предложен альтернативный вариант размещения. Проведена проверка методики определения нитрат-ионов в пресной и соленой воде методом добавок и референтным методом. Основными преимуществами данной методики являются избирательность, экономия используемых реактивов и автоматически настраиваемая частота проведения анализов. Методика может быть использована для автоматического определения нитрат-ионов в природной воде в непрерывном режиме с максимальной производительностью 12 анализов/ч, а также в режиме с меньшей производительностью, с установленным перерывом между анализами.A new express technique for the kinetic catalytic photometric determination of nitrate by stepwise injection analysis is introduced. The detection is based on the catalytic effect of nitrite on the oxidation of ethylendiaminetetreaacetat manganese (II) to red ethylendiaminetetreaacetat manganese (III) by hydrogen peroxide. Nitrate was preliminary reduced to nitrite using copperised cadmium reductor column. The measurement of the red color absorbance was monitored at 520 nm wavelength. Determined the reliable working concentration range to be 0.1 - 5 mg/d

COVID-19 in Patients with Primary Biliary Cholangitis

The aim of the study. To analyze the course of COVID-19 infection in patients with primary biliary cholangitis (PBC).Materials and methods. In a single-center retrospective study, survey and analysis of medical records of 144 patients with PBC was carried out.Results. All patients (n = 144) received basic therapy with ursodeoxycholic acid (UDCA), 5 of them received fibrates as well. Response to therapy (EASL criteria) was obtained in 30 people. Between March 2020 and March 2021, 50 patients (34.7 %) suffered COVID-19, with mean age of 58.8 ± 10.7 years, 16 of which were diagnosed with liver cirrhosis. Mild COVID-19 was observed in 34 (68 %) people, moderate course — in 14 (28 %), severe — in 2 (4 %), cases of extremely severe course were not recorded. 12 patients were hospitalized, 8 of which received oxygen therapy due to a decrease in SpO2 &lt; 94 %, there was no need for the use of other methods of oxygen therapy in any case. The duration of hospitalization was 11.4 ± 5.7 days. There was a higher initial activity of serum alkaline phosphatase (1.8 ± 1.0 versus 1.7 ± 1.4 times of the upper limit of normal, M ± SD, p = 0.04) in patients with COVID-19 infection and lack of UDCA therapy effectiveness was more prominent (40 % vs. 19.1 % of cases, p = 0.04) compared with patients who did not have COVID-19. There were no significant differences in characteristics of the course of PBC (stage, response to therapy) and age in correlation with severity of the course of COVID-19. Among hospitalized patients and those in need of oxygen support, large proportion were older patients (58.3 % and 62.5 %, respectively) and patients with concomitant diseases (62.5 % and 75 %, respectively). Patients who hadn`t previously responded to UDCA therapy were more likely to require oxygen support compared to patients responding to basic therapy (p &lt; 0.01).Conclusion. PBC is not a risk factor for severe COVID-19. A protective effect of UDCA in SARS-CoV-2 infection is possible, which requires further investigation

Biochemical Content of Cambium of Abies nephrolepis

The peculiarity of bears behavior of stripping of bark is typical for all species. We have described the damage to trees, by Asiatic black bear (Ursus thibetanus) and brown bear (U. arctos) in Primorsky Krai and by brown bears on the Sakhalin Island during 1998–2015. In this study, we studied the damaged bark of the tree only in cases where it was clear that part of the cambium was eaten by bears. Cambium of species Abies nephrolepis is the most preferred for bear consumption in Primorsky Krai. We distinguished very large seasonal fluctuations in the amount of its consumption. The greatest interest of bears in this kind of food is in the summer time. We have analyzed the composition of the cambium of A. nephrolepis. These results suggest that the important purpose of the use of this kind of food is to restore and maintain the normal functioning of the intestines