Trapping of 27 bp - 8 kbp DNA and immobilization of thiol-modified DNA using dielectrophoresis

Dielectrophoretic trapping of six different DNA fragments, sizes varying from the 27 to 8416 bp, has been studied using confocal microscopy. The effect of the DNA length and the size of the constriction between nanoscale fingertip electrodes on the trapping efficiency have been investigated. Using finite element method simulations in conjunction with the analysis of the experimental data, the polarizabilities of the different size DNA fragments have been calculated for different frequencies. Also the immobilization of trapped hexanethiol- and DTPA-modified 140 nm long DNA to the end of gold nanoelectrodes was experimentally quantified and the observations were supported by density functional theory calculations.Comment: 17 pages (1 column version), 8 figure

A quantum mechanical model of the upper bounds of the cascading contribution to the second hyperpolarizability

Microscopic cascading of second-order nonlinearities between two molecules has been proposed to yield an enhanced third-order molecular nonlinear-optical response. In this contribution, we investigate the two-molecule cascaded second hyperpolarizability and show that it will never exceed the fundamental limit of a single molecule with the same number of electrons as the two-molecule system. We show the apparent divergence behavior of the cascading contribution to the second hyperpolarizability vanishes when properly taking into account the intermolecular interactions. Although cascading can never lead to a larger nonlinear-optical response than a single molecule, it provides alternative molecular design configurations for creating materials with large third-order susceptibilities that may be difficult to design into a single molecule.Comment: 13 pages, 9 figures, 1 tabl

Dielectrophoresis of nanoscale dsDNA and humidity effects on its electrical conductivity

The dielectrophoresis method for trapping and attaching nanoscale double-stranded DNA between nanoelectrodes was developed. The method gives a high yield of trapping single or a few molecules only which enables transport measurements at the single molecule level. Electrical conductivity of individual 140-nm-long DNA molecules was measured, showing insulating behavior in dry conditions. In contrast, clear enhancement of conductivity was observed in moist conditions, relating to the interplay between the conformation of DNA molecules and their conductivity.Comment: 4 pages, 2 figure

Пасивна система сонячного теплопостачання

The aim of our study is to calculate the passive solar heat supply of a building with the Trombe-Michel (TM) wall, which is located in Chernivtsi. The investigated building has the following parameters: heating area – 50 m2, heating volume – 150 m3. In the section, the TM wall has a trapezoidal profile with an inclination of the south side, with an area of 8×2.7 m2, to the plane of the horizon 67 ° and orientation to the south. From the south, the TM wall is separated from the outside air by double glazing. The arrival of radiation on the southern surface of the TM wall was determined for the following periods: October-November and March-April. In this case, the absorption coefficient of solar radiation by the surface of the TM wall is assumed to be 0.9. The loss of radiation when passing through the glazing is assumed to be 0.83. The average daily heat losses due to the radiation of the surface of the wall into an infinite space with an ambient temperature are determined. At night, the inner side of the glazing is covered with a shield made from a heat-insulating material to reduce heat loss. Being placed in the basement, a gravel battery accumulates about 2 GJ of heat at a temperature of 75 оС during the summer. The battery is charged by supplying hot air through it, which is heated by solar radiation in the gap between the TM wall and the glazing. In October-November period the air taken by the fan from the room passes through the battery and heated enters the room. This ensures a uniform supply of heat to the premises at a rate of 20 MJ per day for October and 48 MJ per day for November. Heat consumption for heating is determined by dissipative losses due to fencing building constructions and heat consumption during ventilation. The seasonal dependence of the total daily heat input taking into account radiation losses and the use of accumulated heat has been established. The replacement coefficient for heat supply f, as part of solar energy in the total required heat consumption for heating, was determined for different values of heat load γ (from 0.7 to 1.3 W/(m3 hail)) during the autumn and spring months. It has been established that when using the TM wall, replacement rate f of the heat supply of the building considered in Chernivtsi at the volum indicated above, the size of the TM wall and the heat capacity of the battery can be from 25 to 100 % for the autumn and spring months depending on the values of heat load γ.Досліджено розрахунковим способом пасивне сонячне теплопостачання енергоощадного будинку в Чернівцях з розташованою в ньому стіною Тромбе-Мішеля, південна поверхня якої площею 8×2,7 м2 нахилена до площини горизонту під кутом 67 о і відділена від навколишнього середовища подвійним склінням. Будівля є одноповерховим двокімнатним приміщенням з опалювальною площею 50 м2 і опалювальним об'ємом 150 м3. У підвалі будинку розташовано тепловий щебеневий акумулятор, який здатний зберігати до 2 ГДж теплоти за температури 75 оС. Влітку для зарядки акумулятора прогріте в проміжку між стіною Тромбе-Мішеля та склінням повітря відбирається вентилятором, продувається через акумулятор тепла, нагріваючи цим самим його теплоакумулятивну насадку. У жовтні-листопаді забране вентилятором з кімнати повітря проходить через акумулятор і нагріте повертається у приміщення. Встановлено сезонну залежність сумарного добового приходу тепла з урахуванням радіаційних втрат і використанням закумульованого тепла. Наведено розрахунок ефективності пасивної системи сонячного опалення розглянутої будівлі у Чернівцях за вказаних її об'єму, розміру стіни Тромбе-Мішеля і ємності теплового акумулятора, визначено коефіцієнти заміщення, з яких видно, що ступінь підтримки теплопостачання в осінні та весняні місяці може становити, залежно від значень теплового навантаження γ (Вт/(м3∙град)), від 25 до 100 %

In Pursuit of Prehistoric Caribou on Thandlät, Southern Yukon

In 1997, the first author noted a large concentration of caribou (Rangifer sp.) fecal pellets and a caribou antler on a permanent snow patch in the Kusawa Lake area of southern Yukon. Caribou are completely absent from this area today. Coring of the snow patch revealed continuous deposits of fecal pellets to depths of at least 160 cm. The proximal portion of a wooden dart or arrow shaft fragment recovered on the edge of the snow patch represents one of the few organic examples of mid-Holocene hunting technology ever found in Canada. An age of 2450 BP ± 50 years was obtained for the fecal material from approximately 1.6 m below the surface of the snow patch, and the dart was dated at 4360 BP ± 50 years. These dates indicate that aboriginal Yukon hunters have been harvesting caribou at this location for at least 4000 years. The Thandlät site offers a rare opportunity to explore a number of questions regarding the prehistoric ecology of large caribou populations, the implications of climate change for caribou populations, and human use of high-elevation hunting sites.En 1997, le premier auteur a découvert une concentration élevée de boulettes fécales (Rangifer sp.) et des bois de caribou sur une congère dans la région du lac Kusawa, dans le sud du Yukon. Il n'y a plus de caribous dans cette région. Le carottage de la congère a révélé des dépôts de boulettes jusqu'à une profondeur de 160 cm. Un fragment de dard ou de la flèche en bois trouvé sur le bord de la congère représente une des rares découvertes au Canada relatives à ce type d'arme. Il a été déterminé que les matières fécales prélevées dans la congère, à environ 1,6 m de profondeur, sont âgées de 2450 BP ± 50 ans, et que le dard aurait 4360 BP ± 50 ans. Ces dates montrent que les Autochtones du Yukon chassaient déjà le caribou à cet endroit il y a 4000 ans. Le site Thandlät est un des rares endroits où l'on peut observer divers aspects préhistoriques des grandes populations de caribou, des effets des changements climatiques sur les populations de caribous et des activités de chasse à grande altitude

Vacuum Rabi splitting and strong coupling dynamics for surface plasmon polaritons and Rhodamine 6G molecules

We report on strong coupling between surface plasmon polaritons (SPP) and Rhodamine 6G (R6G) molecules, with double vacuum Rabi splitting energies up to 230 and 110 meV. In addition, we demonstrate the emission of all three energy branches of the strongly coupled SPP-exciton hybrid system, revealing features of system dynamics that are not visible in conventional reflectometry. Finally, in analogy to tunable-Q microcavities, we show that the Rabi splitting can be controlled by adjusting the interaction time between waveguided SPPs and R6G deposited on top of the waveguide. The interaction time can be controlled with sub-fs precision by adjusting the length of the R6G area with standard lithography methods.Comment: 4 pages, 4 figure

3D plasmonic chiral colloids

3D plasmonic chiral colloids are synthesized through deterministically grouping of two gold nanorod AuNRs on DNA origami. These nanorod crosses exhibit strong circular dichroism (CD) at optical frequencies which can be engineered through position tuning of the rods on the origami. Our experimental results agree qualitatively well with theoretical predictions. © 2014 The Royal Society of Chemistry.Peer Reviewe

The Effect of Pre-Analytical Variability on the Measurement of MRM-MS-Based Mid- to High-Abundance Plasma Protein Biomarkers and a Panel of Cytokines

Blood sample processing and handling can have a significant impact on the stability and levels of proteins measured in biomarker studies. Such pre-analytical variability needs to be well understood in the context of the different proteomics platforms available for biomarker discovery and validation. In the present study we evaluated different types of blood collection tubes including the BD P100 tube containing protease inhibitors as well as CTAD tubes, which prevent platelet activation. We studied the effect of different processing protocols as well as delays in tube processing on the levels of 55 mid and high abundance plasma proteins using novel multiple-reaction monitoring-mass spectrometry (MRM-MS) assays as well as 27 low abundance cytokines using a commercially available multiplexed bead-based immunoassay. The use of P100 tubes containing protease inhibitors only conferred proteolytic protection for 4 cytokines and only one MRM-MS-measured peptide. Mid and high abundance proteins measured by MRM are highly stable in plasma left unprocessed for up to six hours although platelet activation can also impact the levels of these proteins. The levels of cytokines were elevated when tubes were centrifuged at cold temperature, while low levels were detected when samples were collected in CTAD tubes. Delays in centrifugation also had an impact on the levels of cytokines measured depending on the type of collection tube used. Our findings can help in the development of guidelines for blood collection and processing for proteomic biomarker studies