Transverse electric field dragging of DNA in a nanochannel

Nanopore analysis is an emerging single-molecule strategy for non-optical and high-throughput DNA sequencing, the principle of which is based on identification of each constituent nucleobase by measuring trans-membrane ionic current blockade or transverse tunnelling current as it moves through the pore. A crucial issue for nanopore sequencing is the fact that DNA translocates a nanopore too fast for addressing sequence with a single base resolution. Here we report that a transverse electric field can be used to slow down the translocation. We find 400-fold decrease in the DNA translocation speed by adding a transverse field of 10 mV/nm in a gold-electrode-embedded silicon dioxide channel. The retarded flow allowed us to map the local folding pattern in individual DNA from trans-pore ionic current profiles. This field dragging approach may provide a new way to control the polynucleotide translocation kinetics

Chemical characterisation and the anti-inflammatory, anti-angiogenic and antibacterial properties of date fruit (Phoenix dactylifera L.)

Ethnopharmacological relevance: Date fruit, Phoenix dactylifera L. has traditionally been used as a medicine in many cultures for the treatment of a range of ailments such as stomach and intestinal disorders, fever, oedema, bronchitis and wound healing. Aim of the review: The present review aims to summarise the traditional use and application of Phoenix dactylifera date fruit in different ethnomedical systems, additionally the botany and phytochemistry are identified. Critical evaluation of in vitro and in vitro studies examining date fruit in relation to anti-inflammatory, anti-angiogenic and antimicrobial activities are outlined. Key Findings: The ethnomedical use of Phoenix dactylifera in the treatment of inflammatory disease has been previously identified and reported. Furthermore, date fruit and date fruit co-products such as date syrup are rich sources of polyphenols, anthocyanins, sterols and carotenoids. In vitro studies have demonstrated that date fruit exhibits antibacterial, anti-inflammatory and anti-angiogenic activity. The recent interest in the identification of the numerous health benefits of dates using in vitro and in vivo studies have confirmed that date fruit and date syrup have beneficial health effects that can be attributed to the presence of natural bioactive compounds. Conclusions: Date fruit and date syrup have therapeutic properties, which have the potential to be beneficial to health. However, more investigations are needed to quantify and validate these effects

Distraction correction for flexion contractures of the fingers: A minimally invasive technique

Burns injuries account for over 2 million cases in our country. With over 75% of the patients sustaining injuries to the hands, post burn contractures of the finger are a very common condition presenting for treatment. Similarly trauma to the upper limbs, accounting for about a third of all injuries to the body also result in flexion deformities of the fingers. Standard treatment for these deformities is by way of surgical release of the contractures, skin cover with split skin grafting or full thickness grafts followed by prolonged immobilization and splintage. The relatively minimally invasive technique of distraction has been used in this small but representative series to correct flexion deformities caused by burns and other injuries. Results have been very gratifying

Conformational and helicoidal analysis of 30 PS of molecular dynamics on the d(CGCGAATTCGCG) double helix: "curves", dials and windows.

International audienceA new procedure for the analysis of the structure and molecular dynamics of duplex DNA is introduced, in which comprehensive visualization of results and pattern recognition is greatly facilitated. The method involves determining the values of the conformational and helicoidal parameters for each structure entering the analysis using the method "Curves" developed by Lavery and Sklenar, J. Biomol. Str. Dyn. 6, 63 (1988), followed by a novel computer graphic display of the results. The graphic display is organized systematically using conformation wheels, or "dials", for each IUPAC torsional parameter and "windows" on the range of values assumed by the linear and angular helicoidal parameters, and is presented in a form isomorphous with the structure per se. The complete time evolution of the conformational and helicoidal parameters of a DNA double helix can then be depicted in a set of six composite figures. Dynamical aspects of helix bending are also subsumed in this analysis. The procedure is illustrated with an analysis of the structures of canonical A and B forms of DNA and the 300 degrees K native dodecamer duplex d(CGCGAATTCGCG). The "dials and windows" are then used for a comprehensive analysis of 30 psec of molecular dynamics on the dodecamer in the vicinity of a canonical B-DNA energy minimum. This involves presentation of the time evolution of 206 conformational and 230 helicoidal parameters for the dodecamer. A number of interesting structural features can be recognized in the analysis, including crankshaft motions, BI - BII transitions, sugar repuckerings, and a description of spontaneous helix bending at what corresponds to the 1 degrees and 2 degrees "hinge points" indicated in the crystal structure. Our approach is expected to be directly useful for critical analysis of the effects of various assumptions about force field parameters, hydration and electrostatic effects and thus contribute to the development of reliable simulation protocols for nucleic acid systems. Extension of the method to present differential changes in conformational and helicoidal parameters is expected to be valuable for the analysis of structural and molecular dynamics studies of the reorganization and adaptation of DNA on complexation with various drugs and regulatory proteins.A new procedure for the analysis of the structure and molecular dynamics of duplex DNA is introduced, in which comprehensive visualization of results and pattern recognition is greatly facilitated. The method involves determining the values of the conformational and helicoidal parameters for each structure entering the analysis using the method "Curves" developed by Lavery and Sklenar, J. Biomol. Str. Dyn. 6, 63 (1988), followed by a novel computer graphic display of the results. The graphic display is organized systematically using conformation wheels, or "dials", for each IUPAC torsional parameter and "windows" on the range of values assumed by the linear and angular helicoidal parameters, and is presented in a form isomorphous with the structure per se. The complete time evolution of the conformational and helicoidal parameters of a DNA double helix can then be depicted in a set of six composite figures. Dynamical aspects of helix bending are also subsumed in this analysis. The procedure is illustrated with an analysis of the structures of canonical A and B forms of DNA and the 300 degrees K native dodecamer duplex d(CGCGAATTCGCG). The "dials and windows" are then used for a comprehensive analysis of 30 psec of molecular dynamics on the dodecamer in the vicinity of a canonical B-DNA energy minimum. This involves presentation of the time evolution of 206 conformational and 230 helicoidal parameters for the dodecamer. A number of interesting structural features can be recognized in the analysis, including crankshaft motions, BI - BII transitions, sugar repuckerings, and a description of spontaneous helix bending at what corresponds to the 1 degrees and 2 degrees "hinge points" indicated in the crystal structure. Our approach is expected to be directly useful for critical analysis of the effects of various assumptions about force field parameters, hydration and electrostatic effects and thus contribute to the development of reliable simulation protocols for nucleic acid systems. Extension of the method to present differential changes in conformational and helicoidal parameters is expected to be valuable for the analysis of structural and molecular dynamics studies of the reorganization and adaptation of DNA on complexation with various drugs and regulatory proteins