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

Ультразвуковая эластометрия плечевого сплетения после комбинированного лечения рака молочной железы

Shear wave elastometry is important for improving the quality of treatment of patients with postmastectomy edema of the upper limb. Objective: to assess the density of brachial plexus tissues measured by shear wave sonoelastometry in breast cancer patients who received combined modality treatment. Material and Methods. We examined 30 breast cancer patients with postmastectomy edema of the upper limb, who underwent shear wave elastometry of the brachial plexus in the interscalene region. The side where radiation therapy (RT) was delivered was compared with the contralateral (healthy) side in one patient. Results. The median values of tissue stiffness measured by shear wave elastometry were 30.4 (26.2-35.8) and 16.2 (15-19) kPa on the affected and unaffected side, respectively (p<0.001). There was no statistically significant difference in tissue stiffness associated with the age of the patients, right/left side and body mass index. Conclusion. Shear wave elastometry is an alternative method for examining the brachial plexus in radiotherapy for breast cancer. On the RT side, the perineural tissues of the brachial plexus were denser than those on the healthy side. In clinical practice, elastometry can be used to monitor the dynamics of radiation damage and their consequences.Применение эластометрии плечевого сплетения сдвиговой волной важно для повышения качества лечения пациенток с постмастэктомическим отеком верхней конечности. Цель исследования - оценка плотности тканей плечевого сплетения у пациенток после комбинированного лечения рака молочной железы с помощью соноэластометрии сдвиговой волной. Материал и методы. Обследовано 30 пациенток с постмастэктомическим отеком верхней конечности после комбинированного лечения рака молочной железы, которым выполнена эластометрия плечевого сплетения в межлестничной борозде сдвиговой волной. Сравнивали сторону, где применялась лучевая терапия, с контрлатеральной (здоровой) стороной у одной пациентки. Результаты. Медианные значения жесткости ткани в межлестничной борозде, измеренные путем эластометрии сдвиговой волной, составили 30,4 (26,2-35,8) и 16,2 (15-19) кПа на больной и здоровой стороне (р<0,001) соответственно. Не выявлено значимых различий в жесткости тканей, связанных с возрастом пациенток, ведущей стороной (правая/левая) и индексом массы тела. Выводы. Эластометрия сдвиговой волной является альтернативным методом исследования плечевого сплетения при лучевой терапии рака молочной железы. На стороне с применением комбинированного лечения рака молочной железы периневральные ткани плечевого сплетения плотнее, чем на здоровой стороне. В клинической практике эластометрия может быть использована для наблюдения за динамикой лучевых повреждений и их последствий

COMPARATIVE ANALYSIS OF THE LONG-TERM RESULTS OF SURGICAL TREATMENT OF PRIMARY RHEGMATOGENOUS RETINAL DETACHMENT USING EXTRA- AND INTRAOCULAR APPROACHES

Purpose. Analysis of clinical efficacy of surgical treatment of primary rhegmatogenous retinal detachment (PRRD) using extra- and intra-scleral approaches, depending on the stage of proliferative vitreoretinopathy (PVR).Material and methods. The analysis of long-term results in surgical treatment of 116 eyes (112 patients) with PRRD was carried out. Duration of retinal detachment ranged from 7 days to 5 months (average 4.5 weeks). The structure of PVR stages: A – 31 eyes, B – 31 eye, C – 54 eyes. Macular detachment occurred in 47 eyes. Visual acuity preoperatively varied from 0.005 to 1.0 (average 0.25). Extra-scleral approaches were used in 49 eyes of 45 patients. Endovitreal 20G surgery was performed in 67 eyes of 67 patients.Evaluation of the clinical efficacy of treatment in all eyes was carried out in the follow-up period of 3-7 postoperative days and 3-4 years later.Results and discussion. After the extraocular surgery the retinal anatomic reattachment was achieved at 2-3 day of postoperative period in 45 eyes (91.8%). Partial retinal reattachment was revealed in 4 eyes. After reoperation a complete retinal reattachment was achieved in all eyes.After endovitreal surgery it was noted at 2-3 day that the retina attached in 64 eyes (95.5%), in 3 eyes the retinal attachment was failed (4.5%), where a repeated silicone tamponade was performed.Relapses of PRRD occurred in 11 eyes (12.2%), in their structure: 6 eyes after extra-scleral approach – in the period from 2.5 to 12 months; 5 eyes (7.4%) after the intraocular approach – in the period from 4 to 18.5 months. After a repeated endovitreal surgery the anatomic reattachment of retina was achieved in all cases.Conclusions. The main reason of PRRD relapses was the progression of vitreo-proliferative process. Intraocular surgery with the use of plugging fluids (silicone, gas, air) allows more reliably reduce the risk of postoperative complications, occurrence of PRRD relapses. Episcleral approaches in PRRD treatment continue to be the method of choice in the initial PVR stages

Transfer of Synthetic Human Chromosome into Human Induced Pluripotent Stem Cells for Biomedical Applications

AlphoidtetO-type human artificial chromosome (HAC) has been recently synthetized as a novel class of gene delivery vectors for induced pluripotent stem cell (iPSC)-based tissue replacement therapeutic approach. This HAC vector was designed to deliver copies of genes into patients with genetic diseases caused by the loss of a particular gene function. The alphoidtetO-HAC vector has been successfully transferred into murine embryonic stem cells (ESCs) and maintained stably as an independent chromosome during the proliferation and differentiation of these cells. Human ESCs and iPSCs have significant differences in culturing conditions and pluripotency state in comparison with the murine naïve-type ESCs and iPSCs. To date, transferring alphoidtetO-HAC vector into human iPSCs (hiPSCs) remains a challenging task. In this study, we performed the microcell-mediated chromosome transfer (MMCT) of alphoidtetO-HAC expressing the green fluorescent protein into newly generated hiPSCs. We used a recently modified MMCT method that employs an envelope protein of amphotropic murine leukemia virus as a targeting cell fusion agent. Our data provide evidence that a totally artificial vector, alphoidtetO-HAC, can be transferred and maintained in human iPSCs as an independent autonomous chromosome without affecting pluripotent properties of the cells. These data also open new perspectives for implementing alphoidtetO-HAC as a gene therapy tool in future biomedical applications

Development of A Three-zone Combustion Model for Stratified-charge Spark-ignition Engine

A thermodynamic model for calculating the operating process in the cylinder of a spark-ignition engine with internal mixture formation and stratified air-fuel charge based on the volume balance method was developed. The model takes into account the change in the working fluid volume during the piston movement in the cylinder. The equation of volume balance of internal mixture formation processes during direct fuel injection into the engine cylinder was compiled. The equation takes into account the adiabatic change in the volume of the stratified air-fuel charge, consisting of fuel-air mixture volume and air volume. From the heat balance equation, the change in the fuel-air mixture volume during gasoline evaporation in the fuel stream and from the surface of the fuel film due to external heat transfer was determined. Basic equations of combustion-expansion processes of the stratified air-fuel charge were derived, taking into account three zones corresponding to combustion products, fuel-air mixture and air volumes. The equation takes into account the change in the working fluid volume due to heat transfer and heat exchange between the zones and the walls of the above-piston volume. Dependences for determining the temperature in the three considered zones and pressure in the cylinder were obtained. Graphs of changes in the volumes of the combustion products, fuel-air mixture and air zones with the change of the above-piston volume in partial load modes (n=3,000 rpm) were plotted. With increasing load from bmep=0.144 MPa to bmep=0.322 MPa, at the moment of fuel ignition, the volume of the fuel-air mixture increases from 70 % to 92 % of the above-piston volume. At the same time, the air volume decreases from 30 % to 8 %. Analysis of theoretical and experimental indicator diagrams showed that discrepancies in the maximum combustion pressure do not exceed 5

Mixed phenotype cardiomyopathy, associated with DSP genetic variant: a case report and literature review.

We report a case of mixed phenotype cardiomyopathy (non-compaction cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy), associated with DSP genetic variant.  The sudden cardiac death was the first and only symptom

Modulation of Notch Signaling at Early Stages of Differentiation of Human Induced Pluripotent Stem Cells to Dopaminergic Neurons

Elaboration of protocols for differentiation of human pluripotent stem cells to dopamine neurons is an important issue for development of cell replacement therapy for Parkinson’s disease. A number of protocols have been already developed; however, their efficiency and specificity still can be improved. Investigating the role of signaling cascades, important for neurogenesis, can help to solve this problem and to provide a deeper understanding of their role in neuronal development. Notch signaling plays an essential role in development and maintenance of the central nervous system after birth. In our study, we analyzed the effect of Notch activation and inhibition at the early stages of differentiation of human induced pluripotent stem cells to dopaminergic neurons. We found that, during the first seven days of differentiation, the cells were not sensitive to the Notch inhibition. On the contrary, activation of Notch signaling during the same time period led to significant changes and was associated with an increase in expression of genes, specific for caudal parts of the brain, a decrease of expression of genes, specific for forebrain, as well as a decrease of expression of genes, important for the formation of axons and dendrites and microtubule stabilizing proteins