Wet-dry cycles cause nucleic acid monomers to polymerize into long chains.

The key first step in the oligomerization of monomers is to find an initiator, which is usually done by thermolysis or photolysis. We present a markedly different approach that initiates acid-catalyzed polymerization at the surface of water films or water droplets, which is the reactive phase during a wet-dry cycle in freshwater hot springs associated with subaerial volcanic landmasses. We apply this method to the oligomerization of different nucleic acids, a topic relevant to how it might be possible to go from simple nucleic acid monomers to long-chain polymers, a key step in forming the building blocks of life.

Effects of Pulsed Electric Field on the Physicochemical and Structural Properties of Micellar Casein.

Pulsed electric field (PEF) as a green processing technology is drawing greater attention due to its eco-friendliness and potential to promote sustainable development goals. In this study, the effects of different electric field strengths (EFS, 0-30 kV/cm) on the structure and physicochemical features of casein micelles (CSMs) were investigated. It was found that the particle sizes of CSMs increased at low EFS (10 kV/cm) but decreased at high EFS (30 kV/cm).

Investigation of osmotic shock effect on pulsed electric field treated S. cerevisiae yeast cells.

Pulsed electric field (PEF) treatment is known to cause plasma membrane permeabilization of microorganisms, an effect known as electroporation. PEF treatment is very attractive since it can achieve permeabilization with or without lethal damage in accordance with desired results. This study aimed to expand the accomplishment of electroporation outcomes by applying sudden post-PEF osmotic composition change of the media.

Stronger than Ever: Multifilament Fiberglass Posts Boost Maxillary Premolar Fracture Resistance.

This paper investigates the influence of cavity configuration and post-endodontic restoration on the fracture resistance, failure mode and stress distribution of premolars by using a method of fracture failure test and finite elements analysis (FEA) coupled to Weibull analysis (WA). One hundred premolars were divided into one control group (G) ( = 10) and three experimental groups, according to the post-endodontic restoration ( = 30), G, restored using composite, G, restored using single fiber post and G, restored using multifilament fiberglass posts (m-FGP) without post-space preparation. Each experimental group was divided into three subgroups according to the type of coronal cavity configuration ( = 10): G, G and G with occlusal (O) cavity configuration; G, G, and G with mesio-occlusal (MO); and G, G, and G with mesio-occluso-distal (MOD).

Development of a Disposable Polyacrylamide Hydrogel-Based Semipermeable Membrane for Micro Ag/AgCl Reference Electrode.

Currently, Ag/AgCl-based reference electrodes are used in most electrochemical biosensors and other bioelectrochemical devices. However, standard reference electrodes are rather large and do not always fit within electrochemical cells designed for the determination of analytes in low-volume aliquots. Therefore, various designs and improvements in reference electrodes are critical for the future development of electrochemical biosensors and other bioelectrochemical devices.

Pulsed Electric Field: Fundamentals and Effects on the Structural and Techno-Functional Properties of Dairy and Plant Proteins.

Dairy and plant-based proteins are widely utilized in various food applications. Several techniques have been employed to improve the techno-functional properties of these proteins. Among them, pulsed electric field (PEF) technology has recently attracted considerable attention as a green technology to enhance the functional properties of food proteins.

Antimicrobial photodynamic therapy (aPDT) for biofilm treatments. Possible synergy between aPDT and pulsed electric fields.

Currently, microbial biofilms have been the cause of a wide variety of infections in the human body, reaching 80% of all bacterial and fungal infections. The biofilms present specific properties that increase the resistance to antimicrobial treatments. Thus, the development of new approaches is urgent, and antimicrobial photodynamic therapy (aPDT) has been shown as a promising candidate.

Electroporation Assisted Improvement of Freezing Tolerance in Yeast Cells.

Prolonged storage of frozen dough worsens the structure of thawed dough. The main reason is the inhibition of yeast activity. In this study we investigated applicability of pulsed electric field treatment for introduction of cryoprotectant into yeast cells.

Mediated amperometry as a prospective method for the investigation of electroporation.

Pulsed electric field effects induced in a membrane, as well as intracellular structures, depend on cell type, field and media parameters. To achieve desired outcomes, membranes should be permeabilized in a controlled manner, and thus efficiency of electroporation should be investigated in advance. Here, we present a framework for using mediated amperometry as a prospective method for the investigation of electroporation and its effects on cellular machinery.

The link between yeast cell wall porosity and plasma membrane permeability after PEF treatment.

An investigation of the yeast cell resealing process was performed by studying the absorption of the tetraphenylphosphonium (TPP) ion by the yeast Saccharomyces cerevisiae. It was shown that the main barrier for the uptake of such TPP ions is the cell wall. An increased rate of TPP absorption after treatment of such cells with a pulsed electric field (PEF) was observed only in intact cells, but not in spheroplasts.

Pulsed electric field effects on inactivation of microorganisms in acid whey.

Prospects of pulsed electric field technology application on acid whey concentrate pretreatment were analyzed. Stationary and flow pre-treatment systems were combined with different treatment parameters: electric field strength (E = 39 kV/cm, 95 kV/cm, 92 kV/cm), pulse duration (τ = 60 ns, 90 ns, 1000 ns) and pulse number (pn = up to 100 pulses). Isolates of Saccharomyces sp.

Caspase dependent apoptosis induced in yeast cells by nanosecond pulsed electric fields.

Saccharomyces cerevisiae yeast cells were used as a model organism to investigate the effects of various pulsed electric fields on the programed death of such cells. These were exposed to electric field pulses with field strengths (E) of up to 220kV/cm. The effects of square shaped pulses having different durations (τ=10-90ns) and different pulse numbers (pn=1-5) were then analysed.

Total Internal Reflection Accounts for the Bright Color of the Saharan Silver Ant.

The Saharan silver ant Cataglyphis bombycina is one of the terrestrial living organisms best adapted to tolerate high temperatures. It has recently been shown that the hairs covering the ant's dorsal body part are responsible for its silvery appearance. The hairs have a triangular cross-section with two corrugated surfaces allowing a high optical reflection in the visible and near-infrared (NIR) range of the spectrum while maximizing heat emissivity in the mid-infrared (MIR).

Preservation of iridescent colours in Phorinia Robineau-Desvoidy, 1830 (Diptera: Tachinidae).

Background: Iridescent blue-green colours are exhibited by various organisms including several taxa in the Tachinidae (Diptera) with notable examples within the Afrotropical members of the genus Phorinia Robineau-Desvoidy, 1830. The vivid colouration observed in life quickly fades to a dull golden-yellow when a specimen is dried. Although well known, no published explanation has been given for this phenomenon.

Synthesis of bio-inspired multilayer polarizers and their application to anti-counterfeiting.

Some insects, such as Papilio blumei and Suneve coronata, are known for exhibiting polarization effects on light such as color contrast or geometrical polarization rotation by reflection on their wing scales. The photonic structures found on these species that show these properties are multilayered spherical cavities or triangular grooves which polarize the light due to multiple inner reflections. These polarization effects, in addition to the intrinsic color-mixing properties of these photonic structures, are of interest in the anti-counterfeiting field due to their invisibility to the naked eye.

Radiative contribution to thermal conductance in animal furs and other woolly insulators.

This paper deals with radiation's contribution to thermal insulation. The mechanism by which a stack of absorbers limits radiative heat transfer is examined in detail both for black-body shields and grey-body shields. It shows that radiation energy transfer rates should be much faster than conduction rates.

Cylindrical Bragg mirrors on leg segments of the male Bolivian blueleg tarantula Pamphobeteus antinous (Theraphosidae).

The large male tarantula Pamphobeteus antinous is easily recognized at the presence of blue-violet iridescent bristles on some of the segments of its legs and pedipalps. The optical properties of these colored appendages have been measured and the internal geometrical structure of the bristles have been investigated. The coloration is shown to be caused by a curved coaxial multilayer which acts as a "cylindrical Bragg mirror".

Periodontal and systemic responses in various mice models of experimental periodontitis: respective roles of inflammation duration and Porphyromonas gingivalis infection.

Background: The great variability of periodontal and systemic responses to experimental periodontitis reflects the inherent pathogenic complexity of mice models and could limit the resulting interpretations and their extension to human diseases. This study compared the effect of Porphyromonas gingivalis (Pg) infection and experimental periodontitis duration at local and systemic levels in various models.

Methods: Periodontitis was induced in C57BL/6J mice by ligatures previously incubated with Pg (LIGPG group) or not (LIG group) or by oral gavage (GAV) with Pg ATCC 33277.

Photonic polycrystal in the greenish-white scales of the African longhorn beetle Prosopocera lactator (Cerambycidae).

Three-dimensional photonic-crystal grains were found in the scales of the longhorn beetle Prosopocera lactator (Cerambycidae). The local geometric structure can be described as a face-centered-cubic array of spheres, connected by short rods, reminiscent of the "ball-and-stick" models used by solid-state chemists to visualize atomic structures. Based on scanning electron microscopy, x-ray nanotomography, optical measurements, photonic band-structure calculations, and computer simulations of the reflectance, the desaturated greenish coloration is shown to arise from the observed photonic polycrystalline structure.

Structural color produced by a three-dimensional photonic polycrystal in the scales of a longhorn beetle: Pseudomyagrus waterhousei (Coleoptera: Cerambicidae).

The cuticle of the longhorn beetle Pseudomyagrus waterhousei shows a diffuse pattern of mixed blue and violet colors. These colorations arise from a dense layer of droplet-shaped scales covering the dorsal parts of the cuticle. In spite of their lack of iridescence, these colors are shown to be structural and produced by an aggregate of internally ordered photonic-crystal grains.

Reverse color sequence in the diffraction of white light by the wing of the male butterfly Pierella luna (Nymphalidae: Satyrinae).

The butterfly Pierella luna (Nymphalidae) shows an intriguing rainbow iridescence effect: the forewings of the male, when illuminated along the axis from the body to the wing tip, decompose a white light beam as a diffraction grating would do. Violet light, however, emerges along a grazing angle, near the wing surface, while the other colors, from blue to red, exit respectively at angles progressively closer to the direction perpendicular to the wing plane. This sequence is the reverse of the usual decomposition of light by a grating with a periodicity parallel to the wing surface.

Long-term implant survival and success: a 10-16-year follow-up of non-submerged dental implants.

Objectives: The aim of the present study was to evaluate the long-term results of dental implants using implant survival and implant success as outcome variables.

Methods: Of the 76 patients who received 162 implants of the Straumann Dental Implant System during the years 1990-1997, 55 patients with 131 implants were recalled 10-16 years after implant placement for a complete clinical and radiographic examination, followed by a questionnaire that examined the degree of satisfaction. The incidence of biological and technical complications has been carefully analysed for each implant.

Scale coloration change following water absorption in the beetle Hoplia coerulea (Coleoptera).

The blue scales on the cuticle of the male beetle Hoplia coerulea can absorb water, with the consequence that these scales, which have been shown to be responsible for the beetle's bright blue coloration, reversibly turn to emerald green with increasing water contents. Optical measurements are shown, by analytic photonic-crystal models, to be compatible with the full filling of the scales structures with water. The natural mechanism shows the way to produce a very efficient hygrochromic material: a medium which significantly changes color when its water contents are modified.

Use of specific functionalised tips with STM: a new identification method of ester groups and their molecular structure in self-assembled overlayers.

The influence of chemical modification of scanning tunnelling microscopy tips on image contrast is studied. This technique is applied to the identification of an ester functional group, hardly visible otherwise. Self-assembled overlayers of wax esters [CH3-(CH2)14-CO-O-(CH2)15-CH3], adsorbed at the interface between highly oriented pyrolitic graphite and a solution of phenyloctane, are imaged.

Effects of nimesulide and sodium diclofenac on interleukin-6, interleukin-8, proteoglycans and prostaglandin E2 production by human articular chondrocytes in vitro.

Objectives: The aim of this study was to investigate the effects of two nonsteroidal anti-inflammatory drugs (NSAIDs), nimesulide and sodium diclofenac, on the production of proteoglycans (PG), prostaglandin E2 (PGE2) and cytokines (IL-6 and IL-8) by human articular chondrocytes in vitro.

Methods: Enzymatically isolated chondrocytes were cultured under constant agitation in a well defined culture medium. Specific radioimmunoassays were used to quantify PG and PGE2 production.