Clinical effective use of Conquest Pro 12 Sharpened Tip for chronic total occlusion intervention: A series of three case reports.

A new chronic total occlusion (CTO) guidewire, Conquest Pro 12 Sharpened Tip (CP12ST), has a stronger penetration force than the original CP12 and a deflection effect that it does not have. The CP12ST enables us to advance into hard plaque that has not ever penetrated, which might change CTO treatment as shown in three cases.

Effect of microneedles shape on skin penetration and transdermal drug administration.

Microneedle (MN) patches are highly efficient and versatile tools for transdermal drug administration, in particular for pain-free, self-medication and rapid local applications. Diffraction ultraviolet (UV) light lithography offers an advanced method in fabricating poly(ethylene glycol)-based MNs with different shapes, by changing both the UV-light exposure time and photomask design. The exposure time interval is limited at obtaining conical structures with aspect ratio < 1:3, otherwise MNs exhibit reduced fracture load and poor indentation ability, not suitable for practical application. Therefore, this work is focused on a systematic analysis of the MN's base shapes effects on the structural characteristics, skin penetration and drug delivery. Analyzing four different base shapes (circle, triangle, square and star), it has been found that the number of vertices in the polygon base heavily affects these properties. The star-like MNs reveal the most efficient skin penetration ability (equal to 40 % of -their length), due to the edges action on the skin during the perforation. Furthermore, the quantification of the drug delivered by the MNs through ex-vivo porcine skin shows that the amounts of small molecules released over 24 h by star-like MNs coated by local anesthetic (Lidocaine) and an anti-inflammatory (Diclofenac epolamine) drugs are 1.5× and 2× higher than the circular-MNs, respectively.

How head shape and substrate particle size affect fossorial locomotion in lizards.

Granular substrates ranging from silt to gravel cover much of the Earth's land area, providing an important habitat for fossorial animals. Many of these animals use their heads to penetrate the substrate. Although there is considerable variation in head shape, how head shape affects fossorial locomotor performance in different granular substrates is poorly understood. Here, head shape variation for 152 species of fossorial lizards was quantified for head diameter, slope and pointiness of the snout. The force needed to penetrate different substrates was measured using 28 physical models spanning this evolved variation. Ten substrates were considered, ranging in particle size from 0.025 to 4 mm in diameter and consisting of spherical or angular particles. Head shape evolved in a weakly correlated manner, with snouts that were gently sloped being blunter. There were also significant clade differences in head shape among fossorial lizards. Experiments with physical models showed that as head diameter increased, absolute penetration force increased but force normalized by cross-sectional area decreased. Penetration force decreased for snouts that tapered more gradually and were pointier. Larger and angular particles required higher penetration forces, although intermediate size spherical particles, consistent with coarse sand, required the lowest force. Particle size and head diameter effect were largest, indicating that fossorial burrowers should evolve narrow heads and bodies, and select relatively fine particles. However, variation in evolved head shapes and recorded penetration forces suggests that kinematics of fossorial movement are likely an important factor in explaining evolved diversity.

Physicochemical Characteristics and Superficial Damage Modulate Persimmon Infestation by Drosophila suzukii (Diptera: Drosophilidae) and Zaprionus indianus.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) and Zaprionus indianus Gupta (Diptera: Drosophilidae) were recently observed co-infesting persimmons in Brazil. We evaluate the infestation susceptibility of persimmons at different ripening stages (unripe, UN; early ripe, ER; orange ripe, OR, and overripe, OV) by D. suzukii and Z. indianus in the field and laboratory conditions. Additionally, we determined the influence of physicochemical characteristics (e.g., resistance to penetration force, fruit skin color, acidity (pH), TSS concentration, total titratable acidity [TTA]) and the type of damage that facilitates infestation by D. suzukii or Z. indianus. In the field, the natural infestation capacity and biological development of D. suzukii and Z. indianus were verified in whole fruits at the ripening stages ER, OR, and OV. The natural infestation was directly related to the physicochemical characteristics of the fruits (resistance to penetration force, pH, and total soluble solids). In the no-choice bioassay, the oviposition rate of D. suzukii did not differ between the ripening stages of the fruit. However, in the choice bioassay, there was a higher preference for oviposition in OV fruits. Regarding Z. indianus, the highest preference for oviposition was observed in OR and OV fruits in both bioassays. The presence of mechanical damage did not increase the susceptibility of the fruits to D. suzukii. However, it favored the oviposition of Z. indianus in OR and OV fruits. The damage caused by D. suzukii or mechanical damage favored the infestation by Z. indianus. This is the first report of the capacity of D. suzukii to infest whole persimmons in Brazil.

Flexibility of intraoral food processing in the salamandrid newt Triturus carnifex: effects of environment and prey type.

Intraoral food processing mechanisms are known for all major vertebrate groups, but the form and function of systems used to crush, grind or puncture food items can differ substantially between and within groups. Most vertebrates display flexible mechanisms of intraoral food processing with respect to different environmental conditions or food types. It has recently been shown that newts use cyclical loop-motions of the tongue to rasp prey against the palatal dentition. However, it remains unknown whether newts can adjust their food processing behavior in response to different food types or environmental conditions. Newts are interesting models for studying the functional adaptation to different conditions because of their unique and flexible lifestyle: they seasonally change between aquatic and terrestrial habitats, adapt their prey-capture mode to the respective environment, and consume diverse food types with different mechanical properties. Using X-ray high-speed recordings, anatomical investigations, behavioral analyses and mechanical property measurements, we tested the effects of the medium in which feeding occurs (water/air) and the food type (maggot, earthworm, cricket) on the processing behavior in Triturus carnifex We discovered that food processing, by contrast to prey capture, differed only slightly between aquatic and terrestrial habitats. However, newts adjusted the number of processing cycles to different prey types: while maggots were processed extensively, earthworm pieces were barely processed at all. We conclude that, in addition to food mechanical properties, sensory feedback such as smell and taste appear to induce flexible processing responses, while the medium in which feeding occurs appears to have less of an effect.

A short bevel needle with a very thin tip improves vein puncture performance of peripheral intravenous catheters: An experimental study.

BACKGROUND: Peripheral intravenous catheter placement is frequently unsuccessful at the first attempt. One suggested risk factor is a small vein size, because of the consequences of mechanical forces generated by the needle tip. We developed short bevel needles with a very thin tip and evaluated their puncture performance in two in vitro models. METHODS: Peripheral intravenous catheters with a new needle ground using the lancet method (experimental catheter (L)) or backcut method (experimental catheter (B)) were compared with a conventional peripheral intravenous catheter (Surshield Surflo®) in a penetration force test and a tube puncture test. Penetration forces were measured when peripheral intravenous catheters penetrated a polyethylene sheet. The tube puncture test was used to evaluate whether the peripheral intravenous catheters could puncture a polyvinyl chloride tube at two positions, at the center and at 0.5 mm from the center of the tube. RESULTS: Mean penetration forces at the needle tip produced by experimental catheters (L) (0.05 N) and (B) (0.04 N) were significantly lower than those produced by the conventional catheter (0.09 N) (p < 0.01). At the catheter tip, mean forces produced by experimental catheter (B) and the conventional catheter were 0.16 N and 0.26 N, respectively (p < 0.05). In the tube puncture test, the frequency at which the conventional catheter punctured the center-shifted site on the tube at an angle of 20° and speed of 50 mm/min was low (40%). In contrast, experimental catheters (L) and (B) were 100% successful at puncturing both the center and center-shifted sites at 20°. CONCLUSION: Puncture performance was comparable between the lancet-ground and backcut-ground needles except for penetration forces at the catheter tip. The experimental catheters produced lower penetration forces and induced puncture without target displacement at smaller angles compared with the conventional catheter. Therefore, optimization of the needle can prevent vein deformation and movement, which may increase the first-attempt success rate.

Penetration force and cannula sliding profiles of different pen needles: the PICASSO study.

PURPOSE: Pen needles used for insulin injections can have different characteristics that affect a patient's injection experience. The aim of the study was to investigate in a standardized laboratory setting the penetration force and sliding force of different 31/32/33/34 gauge pen needles available in 3.5/4/5/8 mm length and 3/5 bevel tips for subcutaneous injection through pen needles and injection pens. METHODS: Eight different commercially available pen needles were tested in this experimental study. The needle was inserted into a polyurethane substrate at a specific constant speed and the force for insertion was recorded as a function of penetration depth. A load cell was utilized to measure force during the different stages of insertion. RESULTS: Maximum load was lower with the PiC G32×4 when compared with the G32×4 5-bevel needle (p<0.0001), while it was not significantly lower with the PiC G32×4 when compared to the G32×4 3-bevel needle (p=0.064). The comparison of G33×4 PiC and G34×3.5 PiC needles with G32 needles demonstrated significantly lower maximum loads with G33 and G34 (p<0.0001). No difference between needles emerged for sliding results. CONCLUSION: Newer pen needles represent a significant improvement in insulin delivery, reducing the amount of force required to penetrate tissues. Needle tip sharpness and other factors that can reduce the force of insertion such as lubrication are important parameters that can be optimized to increase patient acceptance.

Rapidly Fabricated Microneedle Arrays Using Magnetorheological Drawing Lithography for Transdermal Drug Delivery.

Microneedle arrays (MAs) are among the most promising transdermal drug delivery systems in the last decades due to its minimally invasive nature, convenient operation, and first-pass-metabolism avoidance. However, most MA fabrication methods are difficult to operate, need multiple steps, or require expensive equipment. A novel magnetorheological drawing lithography approach was proposed to rapidly fabricate a flexible microneedle array (FMA) for transdermal drug delivery. A 3D structural liquid MA was drawn in one step from the droplets of curable magnetorheological fluid and maintained its shape under an external magnetic field. The liquid MA was subsequently solidified and sputter-coated with the Ti/Au film to fabricate FMA. FMA morphology, mechanical properties, and transdermal drug delivery performance in vitro were experimentally investigated. FMA consisted of a 5 × 5 cone-shaped microneedle array on a PET flexible substrate. FMA exhibited good strength and excellent penetration performance. It could easily penetrate into skin without breakage, creating microchannels for the promotion of skin permeability. Drugs could be well permeated and diffused in the skin along the microchannels created by FMA. Finally, a dissolvable microneedle array (DMA) was also fabricated by a micromolding technique using FMA as a master template. The DMA exhibited good dissolvable and permeable performance in the agarose block.

Effect of honeybee stinger and its microstructured barbs on insertion and pull force.

Worker honeybee is well-known for its stinger with microscopic backward-facing barbs for self-defense. The natural geometry of the stinger enables painless penetration and adhesion in the human skin to deliver poison. In this study, Apis cerana worker honeybee stinger and acupuncture microneedle (as a barbless stinger) were characterized by Scanning Electron Microscope (SEM). The insertion and pull process of honeybee stinger into rabbit skin was performed by a self-developed mechanical loading equipment in comparison with acupuncture needle. In order to better understand the insertion and pull mechanisms of the stinger and its barbs in human multilayer skin, a nonlinear finite element method (FEM) was conducted. Experimental results showed that the average pull-out force of the stinger was 113.50mN and the average penetration force was only 5.75mN. The average penetration force of the stinger was about one order of magnitude smaller than that of an acupuncture microneedle while the average pull-out force was about 70 times larger than that of an acupuncture microneedle. FEM results showed that the stress concentrations were around the stinger tip and its barbs during the insertion process. The barbs were jammed in and torn the skin during the pull process. The insertion force of the stinger was greatly minimized due to its ultrasharp stinger tip and barbs while the pull force was seriously enhanced due to the mechanical interlocking of the barbs in the skin. These excellent properties are mainly a result of optimal geometry evolved by nature. Such finding may provide an inspiration for the further design of improved tissue adhesives and micro-needles for painless transdermal drug delivery and bio-signal recording.

Monitoring the penetration process of single microneedles with varying tip diameters.

Microneedles represent promising tools for delivery of drugs to the skin. However, before these microneedles can be used in clinical practice, it is essential to understand the process of skin penetration by these microneedles. The present study was designed to monitor both penetration depth and force of single solid microneedles with various tip diameters ranging from 5 to 37µm to provide insight into the penetration process into the skin of these sharp microneedles. To determine the microneedle penetration depth, single microneedles were inserted in human ex vivo skin while monitoring the surface of the skin. Simultaneously, the force on the microneedles was measured. The average penetration depth at 1.5mm displacement was similar for all tip diameters. However, the process of penetration depth was significantly different for the various microneedles. Microneedles with a tip diameter of 5µm were smoothly inserted into the skin, while the penetration depth of microneedles with a larger tip diameter suddenly increased after initial superficial penetration. In addition, the force at insertion (defined as the force at a sudden decrease in measured force) linearly increased with tip diameter ranging from 20 to 167mN. The force drop at insertion was associated with a measured penetration depth of approximately 160µm for all tip diameters, suggesting that the drop in force was due to the penetration of a deeper skin layer. This study showed that sharp microneedles are essential to insert microneedles in a well-controlled way to a desired depth.

A planar Bézier profiled horn for reducing penetration force in ultrasonic cutting.

An ultrasonic planar horn with a Bézier profile is developed. The first longitudinal displacement mode of the horn is exploited for high displacement amplification in order to reduce the penetration force required to enter and cut materials. The displacement amplification and stress distribution characteristics of the Bézier horn and the commonly used catenary horn are examined. The penetration force by the Bézier horn is nearly 75% of that by the catenary horn with a penetration speed of 0.25 mm/s during cutting a tissue stimulant. At a penetration speed of 0.5 mm/s, the penetration force by the Bézier horn is nearly 85% of that by the catenary horn for cutting a polymethylmethacrylate (PMMA) material. The decrease in the penetration force by the Bézier horn is attributed to the fact that the displacement amplification of the Bézier horn is 30% higher than that of the traditional catenary horn with the same length and end surface widths.

A combined experimental and numerical study of stab-penetration forces.

The magnitude of force used in a stabbing incident can be difficult to quantify, although the estimate given by forensic pathologists is often seen as 'critical' evidence in medico-legal situations. The main objective of this study is to develop a quantitative measure of the force associated with a knife stabbing biological tissue, using a combined experimental and numerical technique. A series of stab-penetration tests were performed to quantify the force required for a blade to penetrate skin at various speeds and using different 'sharp' instruments. A computational model of blade penetration was developed using ABAQUS/EXPLICIT, a non-linear finite element analysis (FEA) commercial package. This model, which incorporated element deletion along with a suitable failure criterion, is capable of systematically quantifying the effect of the many variables affecting a stab event. This quantitative data could, in time, lead to the development of a predictive model that could help indicate the level of force used in a particular stabbing incident.