The Effect of the Type of Polyethylene on .the Grafting of Styrene onto Polyethylene. III. The Crosslinking Effect in the Grafting by Preirradiation in Vacuum

The graft-copolymerisation of styrene onto the free radicals trapped in vacuum-irradiated polyethylene was investigated. By an increase of the rigidity of the foils, the grafting rate is also increased, because the termination of the growing chains becomes more hindered. But further increase of the rigidity causes grafting to stop at comparatively low values. Crosslinking of the foils also increases this rigidity, while raising of grafting temperature partially eliminates its effect. Based on the experimental results, some kinetic and structural factors governing the grafting reactions are discussed and some former theories are revised

Thermodynamically self-consistent non-stochastic micromagnetic model for the ferromagnetic state

In this work, a self-consistent thermodynamic approach to micromagnetism is presented. The magnetic degrees of freedom are modeled using the Landau-Lifshitz-Baryakhtar theory, that separates the different contributions to the magnetic damping, and thereby allows them to be coupled to the electron and phonon systems in a self-consistent way. We show that this model can quantitatively reproduce ultrafast magnetization dynamics in Nickel.Comment: 5 pages, 3 figure

Calorimetric Investigation of Grafting of Styrene and Methylmethacrylate onto Air-Preirradiated Polyethylene

All existing and widely used methods for measuring reaction rate of polymerization processes suffer from basic disadvantages including indirect measurement, insufficient accuracy and limited applicability. Their unsuitability is especially pronounced in the investigation of graft copolymerization reactions in which the accuracy of measurement could be affected even by the different properties of individual polymer samples. In this work a new method, calorimetry, free of mentioned disadvantages is generally proposed for investigation of polymerization processes and particularly its application to radiation induced grafting of styrene and methylmethacrylate onto polyethylene is demonstrated. Experimental results showed the possibility of calorimetry to measure the grafting rate continuously and directly in the whole conversion range with the accuracy much better than with any other method used so far. It was concluded that styrene grafting is non-diffusion-controlled, whereas methylmethacrylate grafting is not diffusion- independent. With both monomers the reaction kinetics was found to be dependent on the type of polyethylene a s a consequence of different mechanisms, i. e. in the initiation step two different species, peroxy radicals and peroxides, take part. Its concentration is different in two types of polyethylene used. In the case of high density polyethylene both active species participate in the initiation process equally, according to their different nature. However, in low density polyethylene the concentration of peroxy radicals is negligible compared to that of peroxides and therefore peroxides have dominating role in the initiation step of grafting reaction. The change of the viscosity of reaction medium in the course of reaction as well as the structure of polymer in the case of high density polyethylene influence the kinetics of grafting reaction

The Effect of the Type of Polyethylene on .the Grafting of Styrene onto Polyethylene. III. The Crosslinking Effect in the Grafting by Preirradiation in Vacuum

The graft-copolymerisation of styrene onto the free radicals trapped in vacuum-irradiated polyethylene was investigated. By an increase of the rigidity of the foils, the grafting rate is also increased, because the termination of the growing chains becomes more hindered. But further increase of the rigidity causes grafting to stop at comparatively low values. Crosslinking of the foils also increases this rigidity, while raising of grafting temperature partially eliminates its effect. Based on the experimental results, some kinetic and structural factors governing the grafting reactions are discussed and some former theories are revised

Minimising the impact of scale-dependent galaxy bias on the joint cosmological analysis of large scale structures

We present a mitigation strategy to reduce the impact of non-linear galaxy bias on the joint ‘3 × 2pt’ cosmological analysis of weak lensing and galaxy surveys. The Ψ-statistics that we adopt are based on Complete Orthogonal Sets of E/B Integrals (COSEBIs). As such they are designed to minimize the contributions to the observable from the smallest physical scales where models are highly uncertain. We demonstrate that Ψ-statistics carry the same constraining power as the standard two-point galaxy clustering and galaxy-galaxy lensing statistics, but are significantly less sensitive to scale-dependent galaxy bias. Using two galaxy bias models, motivated by halo-model fits to data and simulations, we quantify the error in a standard 3 × 2pt analysis where constant galaxy bias is assumed. Even when adopting conservative angular scale cuts, that degrade the overall cosmological parameter constraints, we find of order 1σ biases for Stage III surveys on the cosmological parameter S8 = σ8(Ωm/0.3)α. This arises from a leakage of the smallest physical scales to all angular scales in the standard two-point correlation functions. In contrast, when analysing Ψ-statistics under the same approximation of constant galaxy bias, we show that the bias on the recovered value for S8 can be decreased by a factor of ∼2, with less conservative scale cuts. Given the challenges in determining accurate galaxy bias models in the highly non-linear regime, we argue that 3 × 2pt analyses should move towards new statistics that are less sensitive to the smallest physical scales

Termination Reaction in the Anionic Polymerization of Methacrylonitrile

The anionic polymerization of methacrylonitrile initiated by triethylphosphine in dimethylformamide was studied. Experimental evidence for two mechanisms of termination reaction was obtained. By addition of water or alcohol in polymerizing system the rate of polymerization and molecular weight of polymethacrylon1itrile decrease, which proves the termination reaction to be bimolecular and proceed by interaction of the active carbanion with water or alcohol. The rate constant for termination of free anions with water was determined, k~,0 = 2.2 x 102 dm3 moP s-1• The termination reaction could not be excluded by purification and prolonged drying of all components of the system, which indicates that the second mechanism of termination is operative as well. Conductivity measurements gave evidence for a monomolecular spontaneous reaction leading to deactivation of the anion

Calvet Microcalorymetry - a New Suitable Method for Investigation of Polymerization Reactions

The method of Calvet microcalorimetry was used to follow the course of the spontaneous polymerization of styrene. Comparison of this method with widely used point-by-point methods has been performed and the great advantages of calorimetry are shown. Calorimetry measures continuously and directly the reaction rate independently from the physical state of the sample using only one sample for the whole conversion range. The accuracy and sen,sitivity achieved are better than those achieved with other methods. On the basis of these advantages Calvet microcalorimetry can be recommended as very promising method for the investigation of polymerization kinetics

Possibilities of prophylaxis of purulent complications in patients with acute intestinal obstruction

Academia Medicală de Studii Postuniversitare, Harkov, Ucraina, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Mortalitatea postoperatorie prin complicaţii septice acute ce survin la 50-85% dintre pacienţii cu ocluzii intestinale acute (OIA) ajunge pînă la 17-21%. Injectarea intraluminală a antibioticelor, terapia parenterală empirică cu antibiotice, cît şi intubarea intestinului urmată de lavaj nu îmbunătăţesc parametrii indicaţi mai sus. Scopul studiului: Definirea rolului antibioticilor, care reprezintă cel mai răspîndit grup, în profilaxia complicaţiilor purulente septice în OIA. Material şi metode: Au fost analizate rezultatele tratamentului a 176 pacienţi, inclusiv a 62 cazuri diagnosticate cu OIA; obturaţie – în 82 cazuri, iar în 32 cazuri cauza a fost hernia strangulată. Primul grup a inclus 81 pacienţi, 41 dintre care au beneficiat de tratament parenteral cu preparate din grupul aminoglicozidelor şi 40 – preparate din seria penicilinelor. Al doilea grup a inclus 95 pacienţi, la 48 dintre care li s-au administrat preparate din grupul fluorochinolonelor şi 47 – preparate din seria cefalosporinelor. Alegerea preparatelor antibacteriene s-a bazat pe rezultatele studiului experimental de acumulare a antibioticelor în peretele intestinal inflamat. Rezultate: Eficacitatea terapiei antibacteriene a fost estimată prin frecvenţa ritmului cardiac, temperatura corpului, timpul de restabilire a peristalticii, normalizarea indicilor clinici ai sîngelui şi urinei, caracterul şi calitatea complicaţiilor purulente. În ambele grupuri nu au fost stabilite diferenţe semnificative referitoare la temperatura corpului şi timpul de restabilire a peristalticii. Au fost atestate deosebiri semnificative între grupuri în ceea ce priveşte timpul de normalizare a frecvenţei ritmului cardiac, formula sîngelui şi rata complicaţiilor purulente. În grupul al doilea de pacienţi numărul complicaţiilor inflamatorii purulente a fost de 21%, iar în primul grup, în care pacienţilor li s-au administrat preparate aminoglicozide – 33,3%. Concluzii: Utilizarea parenterală a fluorochinolonelor şi cefalosporinelor a influenţat rezultatele experimentului, diminuînd esenţial complicaţiile purulente septice asociate cu OIA.Introduction: Post-operative mortality with acute-septic complications in patients with acute intestinal obstruction (AIO) as its reason in 50-85% cases comprises 17-21%. Intraluminal introduction of antibiotics, empirical parenteral antibiotic therapy as well as intestinal intubation with further lavage did not improve the parameters mentioned above. The aim of study: Definition of antibiotics role, the most widespread groups, in septic complications prophylaxis in AIO. Material and methods: There were analyzed the results of treatment of 176 patients, including 62 cases with diagnosed AIO of adhesive genesis, obstructive – in 82 cases and 32 cases with strangulated hernia. The first group included 81 patients, 41 – have incurred preparations with parenteral aminoglycosides and 40 – preparations with penicillin series. The second group included 95 patients, 48 of them followed preparations with fluoroquinolones and 47 – with cephalosporin. The choice of antibacterial preparations was based on the data of experimental trial on antibiotics cumulation in the wall of inflamed intestine. Results: Efficacy of antibacterial therapy was estimated considering heart rate frequency, body temperature, and terms of peristaltic restoration, normalization of blood and urine tests, character and quality of purulent complications. In the second group of patients (fluoroquinolones and cephalosporins preparations) the number of purulent inflammatory complications was 21%, but in the first group (aminoglycosides) – 33.3%. Conclusion: Parenteral indication of fluoroquinolones and cephalosporines in patients with acute intestinal obstruction influence on the results essentially decreases the number of purulent complications correlated with AIO

Istraživanja dekantacije »crvenog mulja« drniškog boksita

Upotrebom drniskog boksita kod alkalnog rascinjavanja po Bayer-u nastupaju znatne potreskoce. One sastoje u tome, sto se nakon reakcije u autoklavu i razrijedivanja reakcione smjese talozenja crvenog mulja odvija suvise polagano i neravnomjerno, zbog cega se znatno smanjuje produkcija

НАСКІЛЬКИ НАДІЙНИМИ Є КАЛІБРАТОРИ ДЛЯ МЕЛАТОНІНУ СУЛЬФАТУ В СЕЧІ?

Melatonin is a versatile physiological agent that relating to the control of numerous physiologic processes owing to the multiplicity of sites of formation and the presence of melatonin receptors in various places of a human body. The melatonin metabolite 6-sulphatoxymelatonin (alias aMT6s or 6-SMT) infiltrates in urine. Therefore, there is a sense to find the sensitive and selective express-methods for the precise detection of melatonin metabolites in body fluids. The calibrators are proper tools for the signal processing. In the present research work that is the set of few calibers with well-defined concentrations of analyte. Comparison of the measured response of actual sample with reactions of calibers permits to interpret the real signal. Such a response can be either the transmittance or the optical density of sample that are measured by a photometer. The calibration of dose-response relation has been described by logistic Hill's curve with four parameters. The photometric transmittances of analyzed solutions were considered as the response. This paper describes the evaluation and comparison of sets of Hill's parameters for aMT6s-calibrators of independent producers. Reliable calibrators could help to simplify the analysis of urinary melatonin-sulfate dose. Such express-analysis could be more accessible in addition. Hence, the problem of creation of reliable calibrators is still unsolved and challenging.Мелатонин является универсальным физиологическим веществом, которое синтезируется в разных местах человеческого организма и помогает осуществлять контроль над большинством физиологических процессов. Установлено, что метаболит мелатонина 6-сульфатоксимелатонин (сокращенно aMT6s или 6-SMT) выделяется с мочой. Таким образом, есть смысл найти чувствительные и селективные экспресс-методы для точного выявления метаболитов мелатонина в жидкостях организма. Часто калибраторы являются надежными инструментами для обработки сигналов. В данной исследовательской работе это набор нескольких калибраторов с четко определенными концентрациями аналита. Сравнение измеренного отклика фактического образца с реакциями калибраторов позволяет интерпретировать реальный сигнал. Таким откликом может быть либо коэффициент пропускания, или оптическая плотность образца, которая измеряется с помощью фотометра. Выявление надежных калибраторов может существенно упростить анализ дозы мелатони-на-сульфата в моче. Такой экспресс-анализ может быть более доступным. Калибровка отношения доза-реакция была описана логистической кривой Хилла с четырьмя параметрами. Фотометрические коэффициенты пропускания анализируемых растворов рассматривались в качестве отклика. Целью представленной работы была оценка и сравнение наборов параметров Хилла для aMT6s-калибраторов независимых производителей. К сожалению, наш результат демонстрирует значительные и необъяснимые расхождения между ними. Итак, проблема создания надежных калибраторов мочевого мелатонина все еще не решена и актуальна.Мелатонін є універсальною фізіологічною речовиною, яка синтезується в різних місцях людського тіла і допомагає здійснювати контроль над більшістю фізіологічних процесів. Встановлено, що метаболіт мелатоніну 6-сульфаток-симелатонін (скорочено aMT6s або 6-SMT) виділяється з сечею. Таким чином, є сенс знайти чутливі і селективні експрес-методи для точного виявлення метаболітів мелатоніну в рідинах організму. Часто калібратори являються належними інструментами для обробки сигналів. У даній дослідній роботі це є набір кількох калібраторів з чітко визначеними концентраціями аналіту. Порівняння виміряного відгуку фактичного зразка з реакціями калібраторів дозволяє інтерпретувати реальний сигнал. Таким відгуком може бути або коефіцієнт пропускання, або оптична щільність зразка, що вимірюється за допомогою фотометра. Виявлення надійних калібраторів може суттєво спростити аналіз дози мелатоніну-сульфату в сечі. Такий експрес-аналіз може бути більш доступним. Калібрування співвідношення доза-реакція була здійснено логістичною кривою Хілла з чотирма параметрами. Фотометричні коефіцієнти пропускання аналізованих розчинів розглядалися в якості вимірюваного відгуку. Метою представленої роботи була оцінка і порівняння наборів параметрів Хілла для aMT6s-калібраторів незалежних виробників. На жаль, наш результат демонструє значні і нез'ясовані розбіжності між ними. Отже, проблема створення надійних калібраторів сечового мелатоніну все ще не вирішена і актуальна