9 research outputs found
Development of a microchip analytical system with PCR reagents lyophilized into aluminum microchips and modified by the plasma enhanced chemical vapor deposition
Микрочиповые аналитические системы для молекулярно-генетического анализа в последние годы привлекают повышенный интерес исследователей. Алюминиевые микрочипы являются особенно перспективными для внедрения микрочипового формата полимеразной цепной реакции (ПЦР) в лабораторную практику. Подобные микрочипы требуют пассивации поверхности для предотвращения ингибирования ПЦР и улучшения аналитических характеристик системы. Привлекательна и возможность снижения трудозатрат и ошибок оператора за счет лиофилизации реактивов в микрочипах. Микрочипы с лиофилизированными реактивами позволяют избежать сложностей, связанных с хранением при низкой температуре, сокращают количество стадий пипетирования и тем самым уменьшают риск ложноположительных результатов, которые могут быть вызваны контаминацией проб. В работе предложен метод иммобилизации реагентов для ПЦР в микрореакторах алюминиевых микрочипов, поверхность которых была предварительно пассивирована с помощью плазмохимического осаждения из газовой фазы (ПХО). В качестве модельных объектов для лиофилизации выбраны тест-системы для определения фрагмента гена 35S вируса мозаики цветной капусты, используемого в генетически-модифицированных организмах (ГМО), фрагмента геномной ДНК микроорганизма Mycoplasma hominis, а также фрагмента гена глобина человека (белковая часть гемоглобина человека). Разработана экспериментальная установка для лиофилизации, которая позволила оптимизировать условия проведения процесса. Показано, что полученные таким образом алюминиевые микрочипы могут храниться не менее двух месяцев при комнатной температуре, и их аналитические характеристики сравнимы с ПЦР с использованием жидких реактивов, при в 20 раз меньшем потреблении реактивов и в 2-3 раза меньшем количестве операции пипетирования.Microchip analytical systems for the polymerase chain reaction (PCR) have attracted an increased interest of researchers in recent years. Aluminum microchips are particularly promising for the microchip PCR techniques implementation in a routine laboratory practice. However, the surface of the chips needs to be chemically inert for the PCR inhibition prevention and improved analytical characteristics of the system. It should also be noted that the possibility of decreasing of handling procedures and operator mistakes by using lyophilized reagents inside microreactor remains very attractive. Such microchip systems allow avoiding some of the storage difficulties and significantly decrease the number of pipetting stages. All of these lead to minimizing the risk of false positive results due to the sample cross-contamination. In this paper a method of PCR reagents lyophilization into the microreactors of aluminum microchips was developed. The surface of the microchip was modified using the Plasma Enhanced Chemical Vapor Deposition (PE CVD). As the model reagents for the lyophilization, the PCR test systems for 35S gene fragment determination (cauliflower mosaic virus) and human globin (protein part of human GEM) were used. The newly developed experimental system for lyophilization allowed optimizing the process for several microchips. It was shown that the obtained aluminum microchip could be stored under the ambient conditions up to 5 months and their analytical characteristics are comparable with the test-tube PCR, with 20 times less the reagents consumption and 2-3 times less the number of pipetting steps
Analysis of magnesium and levofloxacin complex compounds lipophilicity
The purpose of the study is to evaluate lipophilicity of complex compounds of levofloxacin with magnesium.Цель исследования – оценка липофильности комплексных соединений левофлоксацина с магнием
A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts
Mercury is transported globally in the atmosphere
mostly in gaseous elemental form (GEM, Hg0
gas),
but still few worldwide studies taking into account
different and contrasted environmental settings are
available in a single publication. This work presents
and discusses data from Argentina, Bolivia, Bosnia
and Herzegovina, Brazil, Chile, China, Croatia, Finland,
Italy, Russia, South Africa, Spain, Slovenia and
Venezuela. We classified the information in four
groups: (1) mining districts where this contaminant
poses or has posed a risk for human populations and/or
ecosystems; (2) cities, where the concentration ofatmospheric mercury could be higher than normal due
to the burning of fossil fuels and industrial activities;
(3) areas with natural emissions from volcanoes; and
(4) pristine areas where no anthropogenic influence
was apparent. All the surveys were performed using
portable LUMEX RA-915 series atomic absorption
spectrometers. The results for cities fall within a low
GEM concentration range that rarely exceeds 30 ng m-3,
that is, 6.6 times lower than the restrictive ATSDR
threshold (200 ng m-3) for chronic exposure to this
pollutant. We also observed this behavior in the former
mercury mining districts, where few data were above
200 ng m-3.We noted that high concentrations of GEM
are localized phenomena that fade away in short
distances. However, this does not imply that they do not
pose a risk for those working in close proximity to the
source. This is the case of the artisanal gold miners that
heat the Au–Hg amalgam to vaporize mercury. In this
respect, while GEM can be truly regarded as a hazard,
because of possible physical–chemical transformations
into other species, it is only under these localized
conditions, implying exposure to high GEM concentrations,
which it becomes a direct risk for humans.Grants
CGL2009-13171 and CTM2012-33918 from the Spanish
Ministry of Economy and Competitiveness and PII1I09-0142-
4389 from theCastilla-LaMancha (Spain)RegionalGovernment.Published713-7346A. Monitoraggio ambientale, sicurezza e territorioJCR Journalrestricte
A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts
Mercury is transported globally in the atmosphere
mostly in gaseous elemental form (GEM, Hg0
gas),
but still few worldwide studies taking into account
different and contrasted environmental settings are
available in a single publication. This work presents
and discusses data from Argentina, Bolivia, Bosnia
and Herzegovina, Brazil, Chile, China, Croatia, Finland,
Italy, Russia, South Africa, Spain, Slovenia and
Venezuela. We classified the information in four
groups: (1) mining districts where this contaminant
poses or has posed a risk for human populations and/or
ecosystems; (2) cities, where the concentration ofatmospheric mercury could be higher than normal due
to the burning of fossil fuels and industrial activities;
(3) areas with natural emissions from volcanoes; and
(4) pristine areas where no anthropogenic influence
was apparent. All the surveys were performed using
portable LUMEX RA-915 series atomic absorption
spectrometers. The results for cities fall within a low
GEM concentration range that rarely exceeds 30 ng m-3,
that is, 6.6 times lower than the restrictive ATSDR
threshold (200 ng m-3) for chronic exposure to this
pollutant. We also observed this behavior in the former
mercury mining districts, where few data were above
200 ng m-3.We noted that high concentrations of GEM
are localized phenomena that fade away in short
distances. However, this does not imply that they do not
pose a risk for those working in close proximity to the
source. This is the case of the artisanal gold miners that
heat the Au–Hg amalgam to vaporize mercury. In this
respect, while GEM can be truly regarded as a hazard,
because of possible physical–chemical transformations
into other species, it is only under these localized
conditions, implying exposure to high GEM concentrations,
which it becomes a direct risk for humans
Five-year records of mercury wet deposition flux at GMOS sites in the Northern and Southern hemispheres
International audienceThe atmospheric deposition of mercury (Hg) occurs via several mechanisms, including dry and wet scavenging by precipitation events. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, wet deposition samples were collected for approximately 5 years at 17 selected GMOS monitoring sites located in the Northern and Southern hemispheres in the framework of the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual and seasonal patterns in Hg wet deposition samples. Interannual differences in total wet deposition are mostly linked with precipitation volume, with the greatest deposition flux occurring in the wettest years. This data set provides a new insight into baseline concentrations of THg concentrations in precipitation worldwide, particularly in regions such as the Southern Hemisphere and tropical areas where wet deposition as well as atmospheric Hg species were not investigated before, opening the way for future and additional simultaneous measurements across the GMOS network as well as new findings in future modeling studies
Atmospheric mercury concentrations observed at ground-based monitoring sites globally distributed in the framework of the GMOS network
International audienc