477 research outputs found
The DKP oscillator with a linear interaction in the cosmic string space-time
We study the relativistic quantum dynamics of a DKP oscillator field subject
to a linear interaction in cosmic string space-time in order to better
understand the effects of gravitational fields produced by topological defects
on the scalar field. We obtain the solution of DKP oscillator in the cosmic
string background. Also, we solve it with an ansatz in presence of linear
interaction. We obtain the eigenfunctions and the energy levels of the
relativistic field in that background.Comment: 14 pages, no figure, comments are welcom
Using Artemia urmiana nauplii enriched with HUFA oils in Persian sturgeon (Acipenser persicus) larvae culture
We assessed the effects of Artemia urmiana nauplii as fish food enriched with different oils on growth and survival rate of Persian sturgeon (Acipenser persicus) larvae. Sturgeon ovary oil, cod liver oil, linseed oil and a commercial emulsion (ICES, Belgium Brand) in three levels (100, 200 and 300ppm) for two periods of 12 and 24h were used for enrichment of A. urmiana nauplii fed to Persian sturgeon larvae during 20 days. Length, weight, SGR, CF, FCR and biochemical analyses including fatty acid profiles, total lipid and protein were measured for sturgeon larvae. Maximum length (43.9±2.3mm), DW (34.9±8.7mg), and minimum FCR (1.15±0.21) for sturgeon treatment 12h-200ppm, maximum SGR (13.4±0.6) for sturgeon treatment 12h-300ppm, CF (0.47±0.03) for linseed treatment 12h-300pprn and ICES 12h-300ppm (0.47±0.05), survival (94.1±0.2%) for ICES 24h-200pprn, protein content (70.05%) for ICES 12h-200ppm, lipid (21.14%) for sturgeon ovary oil treatment 24h- 300ppm, Arachidonic acid (ARA) ( 1.54±0.22mg.g OW) for cod liver oil treatment 24h- 300ppm, EPA (3.53±0.36mg.g OW) for cod liver oil 24h-100ppm, and OHA (3.22 ±0.09mg.g OW) for ICES and linseed treatments 24h-200ppm were obtained. DHA/EPA ratio in sturgeon larvae before active feeding was 1.75 which showed no significant difference compared to ICES in two levels (24h-100 and 200ppm) and linseed in two levels (24h-100 and 200ppm). ANOVA of different treatments showed significant differences between length, CF, survival rate, total lipid, ARA, EPA, and DHA contents of the sturgeon larvae among treatments (P<0.05)
Methylene blue usage in the evaluation of traumatic necrosis in a rabbit liver injury model
BACKGROUND: In this study, the efficacy of methylene blue in the differentiation of devascularized and vital areas in a traumatic liver model in rabbits was investigated. METHODS: Twenty healthy rabbits were selected and randomly divided into two equal groups. Surgery was performed through an upper abdominal mid-line incision 5 cm in length. After induction of liver injury, diluted methylene blue was injected through the portal vein and staining onset and discoloration times were recorded. RESULTS: All 20 rabbits survived until the end of the experiment. In cases, non-perfused areas of the liver remained unstained. In control rabbits, liver parenchyma was stained homogeneously. The mean onset time of staining in normal parenchyma was 18.1±1.3 sec in cases and 17.7±1.4 sec in controls (p=NS). The mean discoloration time was 53.1±3.7 sec in cases and 53.1±3.2 sec in controls (p=NS). CONCLUSION: In major liver injuries requiring surgical intervention, methylene blue injection can be used for detection of non-perfused areas in the liver
On the identification of Ti-Ta-Nb-oxides in “wiikites” from Karelia
Purpose. With respect to the nature of Ti-Ta-Nb-oxides, which are included in the mineral associations that have historically gone by the now outdated name of “wiikites”, there is no unanimity of opinion. The main difficulty in identifying them is associated with the complexity of their chemical composition, their metamict structure and the substantial changes in their initial mineral form due to the effects of natural weathering. The aim of this work is the development of methodology to identify Ti-Ta-Nb-oxides corresponding to the mineral formulas AB2O6 and A2B2O7.
Methods. The methodology developed in the work includes two experimental approaches: 1) electron probe microanalysis of phases revealed through use of the SEM-BSE method. Based on the resulting data, a hypothesis about the nature of the Ti-Ta-Nb-oxides in a number of wiikite samples is proposed. 2) XRD analysis of those phases that are formed in the course of thermal annealing of samples from 200 to 1000°C. Based on the resulting data here, the previous hypotheses are either accepted or rejected for each sample.
Findings. Using this methodology, three “wiikite” samples were analyzed (the experimental codes were Wk-2, Wk-3 and Wk-7). The Ti-Ta-Nb-oxides in two of these wiikites (Wk-2 and Wk-3) were preliminarily determined to be hydroxyyttropyrochlore and hydroxycalciobetafite, respectively. In the third sample (Wk-7), the Ti-Ta-Nb-oxide was classified as polycrase. The results of XRD phase analysis of the annealed samples were compatible with the primary hypotheses that hydroxycalciobetafite and polycrase were the initial minerals in “wiikites” 3 and 7, respectively.
Originality. The paper considers the issue of the chemical conditions necessary for the recovery of the original
Ti-Ta-Nb-oxide during recrystallization of the metamict structures. This is a problem that has not been substantively addressed in the literature. Also for the first time experimentally proved the existence of the polycrase in “wiikites”.
Practical implications. Completed work expands our knowledge of the mineral composition of the granitic pegmatites of the Baltic shield and the possibility of their use both for research purposes and for needs of national economy.Мета. Розробка методології ідентифікації Ti-Ta-Nb-оксидів складного хімічного складу з метаміктною структурою, що відповідають мінеральним формулами АВ2О6 та А2В2О7.
Методика. Для розробки методології ідентифікації у роботі використано два експериментальних підходи: 1) рентген-спектральний мікроаналіз фаз, виявлених методом скануючої електронної мікроскопії зразків у назад відображених електронах. На основі отриманих результатів висунута гіпотеза щодо природи Ti-Ta-Nb-оксидів. 2) рентген-дифракційний аналіз фаз, що утворюються в процесі термічного відпалу зразків від 200 до 1000°С. На основі отриманих результатів для кожного зразка первинна гіпотеза приймалася або відкидалася.
Результати. З використанням даної методики були вивчені три зразки “віікітів” (шифри зразків: Wk-2, Wk-3 і Wk-7). Наявність Ti-Ta-Nb-оксидів попередньо визначено e двох зразках (Wk-2 і Wk-3) відповідно, як гідроксііттропірохлор та гідроксікальціобетафіт. У третьому зразку (Wk-7) Ti-Ta-Nb діагностований як полікраз. Результати рентген-дифракційного аналізу відпалених зразків підтвердили гіпотези про те, що початковими мінералами у Wk-3 і Wk-7 були гідроксікальціобетафіт і полікраз відповідно.
Наукова новизна. Визначено хімічні умови, необхідні для утворення початкового Тi-Ta-Nb під час рекристалізації метаміктної структури, що раніше не розглядалось у відповідній тематичній науковій літературі. Вперше експериментально виявлено присутність у “віікітах” полікраза.
Практична значимість. Отримані результати розширюють й доповнюють знання щодо мінерального складу гранітних пегматитів Балтійського щита та надають можливість їх використання в дослідницьких цілях і потребах народного господарства.Цель. Разработка методологии идентификации Ti-Ta-Nb-оксидов сложного химического состава с метамиктной структурой, соответствующих минеральным формулам АВ2О6 и А2В2О7.
Методика. Для разработки методологии идентификации в работе использовано два экспериментальных подхода: 1) рентген-спектральный микроанализ фаз, выявленных методом сканирующей электронной микроскопии образцов в обратно отраженных электронах. На основе полученных результатов выдвинута гипотеза о природе Ti-Ta-Nb-оксидов. 2) рентген-дифракционный анализ фаз, образующихся в процессе термического отжига образцов от 200 до 1000°С. На основе полученных результатов для каждого образца первоначальная гипотеза принималась или отвергалась.
Результаты. С использованием данной методики были изучены три образца “виикитов” (шифры образцов: Wk-2, Wk-3 и Wk-7). Наличие Ti-Ta-Nb-оксидов предварительно определено в двух образцах (Wk-2 и Wk-3) соответственно, как гидроксииттропирохлор и гидроксикальциобетафит. В третьем образце (Wk-7)
Ti-Ta-Nb диагностирован как поликраз. Результаты рентген-дифракционного анализа отожженных образцов подтвердили гипотезы о том, что первоначальными минералами в Wk-3 и Wk-7 были гидроксикальциобетафит и поликраз соответственно.
Научная новизна. Определены химические условия, необходимые для образования первоначального Тi-Ta-Nb во время рекристаллизации метамиктной структуры, что ранее не рассматривалось в соответствующих тематических научных литературе. Впервые экспериментально выявлено присутствие в “виикитах” поликраза.
Практическая значимость. Полученные результаты расширяют и дополняют знания о минеральном составе гранитных пегматитов Балтийского щита и дают возможности их использования в исследовательских целях и нуждах народного хозяйства.The study was conducted using equipment of the Center of X-ray Diffraction Studies and the Center for Microscopy and Microanalysis of the Research Park at Saint Petersburg State University, as well as the analytical laboratory of OJSC MMC Norilsk Nickel in Saint Petersburg
Peritoneal Potassium and pH Measurement in Early Diagnosis of Acute Mesenteric Ischemia in Rats
Background: In contemporary practice, acute mesenteric ischemia (AMI) remains a serious cause of morbidity and mortality in abdominal emergencies.
Objectives: We report the measurement of peritoneal fluid potassium and pH on a small series of rats that developed extensive AMI following the surgical ligation of superior mesenteric vessels and compare the results with control groups.
Materials and Methods: A total of 32 rats were used in our study. They were divided into four groups with eight rats in each one and received following treatments: group I (G-I), 60-minute controls; group II (G-II), 120-minute controls; group III (G-III), 60-minute cases; and group IV (G-IV), 120-minute cases. In case groups, the small bowel mesenteric root was double-ligated and an arrow single-lumen central venous catheter was passed through the skin to the peritoneum. In control groups, the catheter was placed without any intervention. Postoperatively, peritoneal lavage was performed at 60 (G-I, G-III) and 120 minutes (G-II, G-IV).
Results: The mean peritoneal potassium values were 1.3 ± 0.3, 1.97 ± 1.06, 2.14 ± 0.89, and 3.28 ± 0.66 mmol/L in G-I, G-II, G-III, and G-IV, respectively. There were significant differences between G-III and G-IV (P = 0.002), between G-I and G-III (P = 0.024), and between G-II and G-IV (P = 0.001). The mean values of peritoneal fluid pH were 7.1 ± 0.26, 6.82 ± 0.22, 6.66 ± 0.16, and 6.78 ± 0.04 in G-I, G-II, G-III, and G-IV, respectively, which indicated significant differences between G-I and G-III (P = 0.001) and between G-II and G-IV (P = 0.018). There was a significant correlation between peritoneal fluid potassium and intestine ischemic grade (F = 4.77, P = 0.048)
Conclusions: Our findings show that for early detection of bowel ischemia, an evaluation of intraperitoneal potassium and pH was useful and with prolongation of ischemia, potassium changes were more significant
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