N-alkylaryl styrylcyanine dyes as fluorescent probes for nucleic acids detection

Aim. To synthesize and characterize a series of N-alkylaryl benzothiazole styrylcyanine dyes as potential fluorescent probes for nucleic acids (NA) detection. Methods. Synthesis, absorption and fluorescence spectroscopy, gel electrophoresis. Results. The modification of N-alkyl styrylcyanine by variation of aromatic moieties insignificantly affected its inherent fluorescent properties. Weakly fluorescent in an unbound state, the dyes noticeably increased their emission upon binding to dsDNA/RNA (up to 83-fold for the derivative with N-alkylbenzylamine group (Sbt1) complexed with dsDNA: with a binding constant (Kb) of 5.0×104 M⁻¹, detection limit of dsDNA in solution of 6.2×10⁻⁷ Mbp (0.4 µg)). When bound to dsDNA, styrylcyanines have moderate quantum yields (up to ~22 %). The variation of structure of the terminal aromatic group allowed to discriminate between dsDNA and RNA: the fluorescence of the Sbt2 dye with the N-alkylphenantroline group increased 14 and 55-fold, respectively. A higher discernibility of post-electrophoretic staining at low DNA concentrations (3.6 ng/lane) by the Sbt3 dye with the N-alkyldipyridyl group was observed compared to the commonly used ethidium bromide. Conclusions. Due to the sensitivity of novel styrylcyanines to NA in solution and in gel electrophoresis, they could be proposed as photostable, low-toxic and inexpensive fluorescent probes for laboratory use.Мета. Синтезувати і охарактеризувати у якості флуоресцентних зондів на нуклеїнові кислоти (НК) серію нових N-алкіларил функціоналізованих бензтіазол стирилціанінових барвників. Методи. Синтез, флуоресцентна і абсорбційна спектроскопія, метод гель-електрофорезу. Результати. Різні термінальні арильні групи в N-алкіл позиції барвника незначно впливають на його флуоресцентні властивості. Барвники, що мають слабку флюоресценцію у вільному стані, значно підвищують емісію при зв'язуванні з длДНК / РНК (до 83 раз при зв'язуванні Sbt1 з N-алкілбензиламінною групою з ДНК, його константа зв'язування (Kb) – 5.0×104 M⁻¹, межа визначення длДНК в розчині – 6.2×10⁻⁷ М п.о. (0.4 µg)). У комплексі з ДНК квантові виходи стирилціанінів є середніми (до ~22%). Структура термінальної ароматичної групи в N-заміснику може визначати здатність барвника відрізняти длДНК від РНК, наприклад у Sbt2 з N-алкілфенантроліновою групою емісія зростає в 14 і 55 рази відповідно. Показано, що пост-електрофоретичне забарвлення низької концентрації ДНК (3.6 нг/лінія) за допомогою барвника Sbt3 з N-алкілдіпірідильною групою дає більш чітку візуалізацію у порівнянні з широко використовуваним бромистим етидієм. Висновки. Завдяки чутливості нових стирилціанінів до НК в розчині і при гель-електрофорезі, вони можуть бути запропоновані в якості фотостабільних низькотоксичних недорогих флуоресцентних зондів для рутинних лабораторних експериментів.Цель. Синтезировать и охарактеризовать в качестве флуоресцентных зондов для определения нуклеиновых кислот (НК) серию N-алкиларил функционализированых бензтиазол стирилцианиновых красителей. Методы. Синтез, флуоресцентная и абсорбционная спектроскопия, метод гель-электрофореза. Результаты. Различные терминальные арильные группы в N-алкил положении красителя незначительно влияют на его флуоресцентные свойства. Слабо флуоресцирующие в свободном состоянии, красители значительно повышают эмиссию при связывании с дцДНК/РНК (до 83 раз при связывании Sbt1 с N-алкилбензиламинной группой с ДНК, его константа связывания (Kb) – 5.0×104 M⁻¹, предел определения дцДНК в растворе – 6.2×10⁻⁷ М п.о. (0.4 µg)). В комплексе с ДНК квантовые выходы стирилцианинов средние (до ~22 %). Вариация ароматического N-терминальных заместителя может придать красителю способность различать определенные типы НК; так, для Sbt2, содержащего N-алкилфенантролиновую группу, наблюдается увеличение флуоресцентнции в 14 и 55 раз соответственно. Показано, что пост-электрофоретическое окрашивание низких концентраций ДНК (3.6 нг/линия) с помощью красителя Sbt3 с N-алкилдипиридильной группой дает более четкую визуализацию по сравнению с широко используемым бромистым этидием. Выводы. Благодаря чувствительности новых стирилцианинов к НК в растворе и при гель-электрофорезе, они могут быть предложены в качестве фотостабильных низкотоксичных недорогих флуоресцентных зондов для рутинных лабораторных экспериментов

Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques

When duplex stainless steels are heated, they can become sensitised and intermetallic phases can appear. In this work, samples of duplex stainless steel, UNS 1.4462, have been heated (850 degrees C for 1 and 2 h) in a heating unit that can be accommodated to a confocal microscope in order to study the morphological changes in-situ. The electrochemical behaviour of the samples has been analysed by means of conventional and localised electrochemical techniques. According to the results, there is a general decrease in the steel resistance to localised corrosion; this decrease can be related to defects in the formed passive film.We wish to express our gratitude to MICINN (CTQ2009-07518), to Universitat Politecnica de Valencia (CEI-01-11), to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRM/S/100), to Professor Alda Simoes and Andreia Marques for the help on LEIS measurements and to Dr. Asuncion Jaime for her translation assistance.Leiva García, R.; Fernandes, JS.; Muñoz-Portero, M.; Garcia-Anton, J. (2015). Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques. Corrosion Science. 94:327-341. https://doi.org/10.1016/j.corsci.2015.02.016S3273419

Environmental Influences on the Relation between the 22q11.2 Deletion Syndrome and Mental Health:A Literature Review

22q11.2 deletion syndrome (22q11DS) is a clinically heterogeneous genetic syndrome, associated with a wide array of neuropsychiatric symptoms. The clinical presentation is likely to be influenced by environmental factors, yet little is known about this. Here, we review the available research literature on the role of the environment in 22q11DS. We find that within-patient design studies have mainly investigated the role of parental factors, stress, and substance use, reporting significant effects of these factors on the clinical profile. Case-control studies have been less successful, with almost no reports of significant moderating effects of the environment. We go on to hypothesize which specific environmental measures are most likely to interact with the 22q11 deletion, based on the genes in this region and their involvement in molecular pathways. We end by discussing potential reasons for the limited findings so far, including modest sample sizes and limited availability of environmental measures, and make recommendations how to move forward

Micro-alloyed Mg-Ca: Corrosion susceptibility to heating history and a plain problem-solving approach

The exceptionally low corrosion rate (∼0.1 mm y–1 in concentrated NaCl solution for 7 days) enables lean Mg-Ca alloys great potential for diverse applications, particularly if relevant properties (e.g. mechanical strength, electrochemical performance, etc.) can be enhanced by thermomechanical processing. However, herein it is demonstrated that the corrosion performance of lean Mg-Ca is susceptible to the heating process. The corrosion rate of Mg-0.15 wt% Ca alloy is remarkably accelerated after annealing even for a short time (4 h at 400 °C) because Fe precipitation readily takes place. Fortunately, it is found that micro-alloying with dedicated additional elements is able to solve this problem. Nevertheless, the problem-solving capability is dependent on the element category, particularly the ability of the alloying element to constrain the Fe precipitation. Among the three studied elements (i.e. Sn, Ge and In), only In shows good competence of restricting the formation of Fe-containing precipitates, thereby contributing to retention of the superior corrosion resistance after annealing even at a rigorous condition (24 h at 450 °C). The finding creates good foundation for follow-up work of developing lean Mg-Ca-based alloys combining high corrosion resistance, superior electrochemical performance with excellent mechanical properties for applications as biodegradable implants and anode materials for aqueous batteries

Zn-Al layered double hydroxides as chloride nanotraps in active protective coatings

Zn–Al layered double hydroxides (LDHs) intercalated with nitrate anions are suggested as chloride nano-traps for organic polymeric coatings. The addition of such nanotraps to a polymer layer drasticallyreduces the permeability of corrosive chloride anions through the protective coatings. In solution,Zn(2)–Al–NO3LDHs are responsive to the concentration of chlorides and the release of nitrates is accom-panied by entrapment of chlorides, with the process governed by ion-exchange equilibrium. In particular,a coating modified with LDH–NO3was found to exhibit significantly lower permeability to chlorideswhen compared to both unmodified and LDH–Cl-containing coatings, which proves the applicability ofLDHs in delaying coating degradation and corrosion initiation.publishe

Hybrid epoxy-silane coatings for improved corrosion protection of Mg alloy

New hybrid epoxy-silane coatings, with added functionalities for improved performance and durability, were designed to increase the corrosion protection of magnesium alloys. The corrosion behavior of the coated AZ31 was studied through electrochemical impedance spectroscopy (EIS) in 0.05 M NaCl. The morphology and surface chemistry of the samples were also investigated through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) before and after immersion in the electrolyte. The new hybrid silane coatings showed a high resistance to corrosion that persisted throughout one-month immersion in a pH-neutral NaCl solution. (c) 2012 Elsevier Ltd. All rights reserved