Short Tip Research Articles

Laminin Network Formation Studied by Reconstitution of Ternary Nodes in Solution

The polymerization of laminins into a cell-associated network is a key process in basement membrane assembly. Network formation is mediated by the homologous short arm tips of the laminin heterotrimer, each consisting of a globular laminin N-terminal (LN) domain followed by a tandem of laminin-type epidermal growth factor-like (LEa) domains. How the short arms interact in the laminin network is unclear. Here, we have addressed this question by reconstituting laminin network nodes in solution and analyzing them by size exclusion chromatography and light scattering. Recombinant LN-LEa1-4 fragments of the laminin α1, α2, α5, β1, and γ1 chains were monomeric in solution. The β1 and γ1 fragments formed the only detectable binary complex and ternary complexes of 1:1:1 stoichiometry with all α chain fragments. Ternary complex formation required calcium and did not occur at 4 °C, like the polymerization of full-length laminins. Experiments with chimeric short arm fragments demonstrated that the LEa2-4 regions of the β1 and γ1 fragments are dispensable for ternary complex formation, and an engineered glycan in the β1 LEa1 domain was also tolerated. In contrast, mutation of Ser-68 in the β1 LN domain (corresponding to a Pierson syndrome mutation in the closely related β2 chain) abolished ternary complex formation. We conclude that authentic ternary nodes of the laminin network can be reconstituted for structure-function studies.

Artificially selected human sperm morphology after swim-up processing

The swim-up technique is a clinical practice used to select highly motile sperm cells from patient ejaculates to use in assisted fertilization. The aim of this study was to investigate whether the length of different sperm-cell components is related to gamete function. Thus, we explored whether swim-up technique selects for longer sperm cells than mean sperm cells from unprocessed ejaculates. Sperm midpiece, tail endpiece, and total length were measured before and after the swim-up selection by means of contrast-phase and electron microscopy. Correlations between sperm dimensions, sperm motility, and sperm concentration were also investigated. Swim-up selected cells with longer midpiece compared with the unprocessed fractions (5.8 μm (CI 5.52–6.16 μm) vs. 5.3 μm (CI 4.97–5.61 μm), p < 0.05) and shorter tail endpiece (7.8 μm (CI 7.11–8.44 μm) vs. 8.5 μm (CI 7.81–9.14 μm), p < 0.05 after meta-analysis), whereas no effect of swim-up selection was detected on the total sperm cell length. Individuals producing high sperm concentrations had longer sperm midpiece than had men producing lower sperm concentrations. It is concluded that short sperm flagellar tips with long midpieces may be used as biomarkers in infertility therapy.

Two new species of Siconema (Drilonematoidea: Ungellidae) parasitic in earthworms in Vietnam, and systematic relationships as inferred from ribosomal sequence data

Two new species of Siconema (Drilonematoidea: Ungellidae) from Pu Mat Nature Reserve, Vietnam are described andillustrated. Siconema ovicallosum sp. n. is characterised by a wide female body, female caudal organs displaced toposterior extremity followed by short tail tip; males short, slim with caudal organs near cloacal opening and long, conicalposterior portion of tail; cephalic hooks in both sexes with sturdy base and thin, diverging blade tips; tubular stomaincorporated in hooks base; eggs with very thick shells and two suberose polar caps. It is most similar to S. laticaudatumIvanova & Pham Van Luc, 1997 but is distinguished by much smaller males, their caudal organs, and the shape andornamentation of eggshells. Siconema diducuncinum sp. n. is characterised by a stoma that is confined in a tube thatprotrudes between thin hooks with widely distributed blades, caudal organs situated at long distance from the tail tip, eggsin the shape of a double-poled elongated lemon and presence of a copulatory disc in males. Siconema diducuncinum sp.n. is most closely related to S. sinense Timm, 1966 but differs from it by having rounded vs elongate pharyngeal bulb,thinner and smoother eggshells with more pronounced polar caps, twisted vs straight ovary and a copulatory disc in males.By an elongated tail spike and bristling hook blades, S. diducuncinum sp. n. shares similarities with S. neozelandicumYeates & Spiridonov, 1996 but differs in having a non-amalgamated hook base, presence of projecting stomatal tube,differently ornamented eggshells and a copulatory disk in males. A key to species of Siconema is given. Phylogenetic relationships of the new species and other drilonematids are discussed.

Relation between the chemical force and the tunnelling current in atomic point contacts: a simple model

The relation between the tunnelling current It and the interaction energy/force E in an atomic-scale contact is discussed in the framework of a theoretical model established here. According to our model, we predict the existence of two characteristic scaling regimes, where the tunnelling current is either proportional to the interaction energy, It ∼ E, or to the square of the interaction energy, It ∼ E2. We show that the existence of a given regime is basically controlled by two parameters: (i) the energy degeneracy Δ and (ii) the hopping t between electronic levels involved in the interaction process. In addition, we discuss the validity of the Bardeen method to determine the tunnelling current in the short tip–sample distances.

Evaluation of Skin and Subcutaneous Adipose Tissue Thickness for Optimal Insulin Injection

Patient’s skin and subcutaneous adipose tissue thicknesses are the primary criteria that determine the optimal insulin needle length in subcutaneous insulin treatment. The present study aims to measure skin thickness and subcutaneous adipose tissue thickness in patients with diabetes mellitus and to investigate the association of these measurements with waist circumference and body mass index. The study included 449 subjects (152 patients with DM and 297 healthy controls, mean age: 44.58 ± 14.25 year) aged 18 years or older. The primary endpoint was the time of comparison of skin thicknesses and subcutaneous adipose tissue thicknesses between patients with diabetes mellitus and healthy subjects and the secondary endpoint was the time of assessment of the relationship between skin and subcutaneous adipose tissue thicknesses and body mass index and waist circumference. Skin and subcutaneous adipose tissue thicknesses were measured by ultrasonography. Overall, average skin thickness values were 1.95 mm (1.05-3.92) for triceps, 2.35 mm (1.07-3.82) for anterior abdomen and 1.97 mm (1.12-3.12) for anterior thigh, while subcutaneous adipose tissue thicknesses were 6.42 mm (1.01-33.5) for triceps, 15.73 mm (1.04-39.3) for anterior abdomen and 7.92 mm (1.48-31.6) for anterior thigh. Triceps and anterior thigh skin thickness values were higher in the diabetes mellitus group compared to healthy controls (p<0.01 for both) while subcutaneous adipose tissue thicknesses were similar between the two groups. There was a positive correlation between body mass index and waist circumference and between skin and subcutaneous adipose tissue thicknesses (p<0.01 for both). The largest skin thickness measured in the present study was 3.92 mm, which supports the previous reports that short needle tips could be used safely in individuals with diabetes mellitus.

Angled long tip to tuning fork probes for atomic force microscopy in various environments

We expand the range of applications of a tuning fork probe (TFP) in frequency-modulation atomic force microscopy (FM-AFM) by attaching a long metal tip at a certain angle. By the combined flexure of the metal tip and the tuning fork prong, this TFP can change the direction of the detectable force by switching the resonance frequency, which has not been realized with conventional TFPs with short tips. The oscillatory behavior of the tip apex of the TFP is predicted by computer simulations and is experimentally confirmed with scanning electron microscope. FM-AFM operations using this TFP are performed in various environments, i.e., in ultrahigh vacuum, air, and water. FM-AFM images obtained at an atomic step of highly oriented pyrolytic graphite in air show a clear difference depending on the excitation frequency. It is also revealed that the higher order flexural modes of this TFP are advantageous for FM-AFM in water due to the reduction in the degree of hydrodynamic damping.

Study on the Dimethyl Ether Spray Characteristics According to the Diesel Blending Ratio and the Variations in the Ambient Pressure, Energizing Duration, and Fuel Temperature

The purpose of this study was to investigate the effects of the energizing duration, ambient gas pressure, fuel temperature, and diesel−dimethyl ether (DME) blending ratio on DME spray characteristics. The DME spray characteristics were analyzed using the spray images obtained from the spray visualization system. The experimental results for the DME spray were compared to the numerical results calculated using KIVA code. DME fuel had a shorter spray tip penetration and a wider spray cone angle compared to those of conventional diesel fuel atomization. DME spray became blurry at the outer region of the spray, and its evaporation was more active than that of diesel fuel. The droplet sizes of DME were much smaller than those of diesel fuel because of the low kinematic viscosity and evaporation of DME. In the results of calculations, the increased ambient gas pressure caused restraint in spray development and entrainment of the surrounding air. On the other hand, the short energizing duration induced short spray tip penetration; however, the variation in the energizing duration had little effect on the spray cone angle. The elevated ambient gas pressure retrained the DME spray development, which increased the spray cone angle of DME.

Propyl-Ended Hemifluorinated Surfactants: Synthesis and Self-Assembling Properties

The advantages of using hemifluorinated surfactants as an efficient alternative to detergents for manipulating membrane proteins in aqueous solution have been demonstrated in recent reports. However, the large-scale synthesis of these surfactants is still considered as a major matter and has limited their use for biochemical purposes. We report herein the synthesis of a novel series of perfluorohexane-based surfactants endowed with a short propyl hydrocarbon tip and whose polar head size is modulated by the presence of two or three glucose moieties. The synthetic route is based on the radical addition of two alkenes onto the 1,6-diiodoperfluorohexane using AIBN as a radical initiator, affording the surfactants in satisfactory overall yields. The self-assembling properties of these hemifluorinated surfactants were studied by surface tension measurements, dynamic light scattering, as well as their behavior upon reversed-phase chromatography and were compared with those of their perfluorinated analogues. Our findings strongly suggest the predominant influence of the propyl tip on both adsorption and micellization phenomena as well as on the hydrophobic character of the surfactants, whereas as previously observed, the shorter ethyl tip does not greatly affect these properties when compared to the perfluorinated analogues. Moreover, all the surfactants reported here self-assemble into small and monodisperse aggregates, a feature of crucial importance for biochemistry applications.

A new dedicated ultrashort steerable balloon for side branch ostial dilatation

A dedicated balloon with a short beveled tip and the ability to rotate it from the proximal hub was successfully used to dilate the origin of a side branch which became totally occluded after deployment of a stent in the main vessel. Although regular low profile balloons are mostly successful in crossing struts of previously deployed stents, this new device has the potential to offer a more predictable and rapid solution in routine practice.

Ammonium-Stimulated Root Hair Branching is Enhanced by Methyl Jasmonate and Suppressed by Ethylene in Arabidopsis thaliana

Root hair development is orchestrated by nutritional factors and plant hormones. We investigated the action of ammonium (NH 4 + ) and its interactions with methyl jasmonate (MeJA) and ethylene in Arabidopsis root hair growth. The formation of root hair branches was dramatically stimulated in media containing 1.25 to 20 mM NH 4 + at pH values of 4.0 to 6.5. The NH 4 + -treated root hairs showed a very short tip growth stage and swells on the sides that indicated the emergence of branches. MeJA (0.08 to 10 μM) worked in synergism with NH 4 + to enhance hair branching. In contrast, ethylene had an antagonistic effect; the stimulation of hair branching by NH 4 + was suppressed by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and was diminished in ethylene-overproducing mutant eto1-1 seedlings. Moreover, the application of Ag+, an ethylene inhibitor, reduced the ACC-induced inhibition of NH 4 + -stimulated hair branching and restored NH 4 + -stimulated hair branching in eto1-1 seedlings. Thus, the actions of jasmonate and ethylene appear to be dependent on nutritional conditions such as available nitrogen.

Electron emission from silicon tip arrays controlled by np junction minority carrier injection

The authors demonstrate for the first time the injection of electrons across an n-type to p-type silicon junction and their subsequent tunneling from approximately 1 μm tall p-type silicon points into a vacuum gap. The diffusive flow of these minority carriers in the p-type material is controlled by the application of a bias voltage in the form of a base contact metallization contact on the p-type silicon, in analogy with a bipolar junction transistor. Using an array density of 4×106 tips/cm2, the authors measured a maximum average current of 1 nA per tip. Increasing the base contact bias voltage from 0 to ∼1 V changes the emission from a supply limited regime typically observed with p-type silicon emitters, bringing the emitted current back to a linear Fowler–Nordheim characteristic similar to that observed previously by photon generation of carriers in p-type silicon tips. The authors finally note that in our short tips, minority carrier flow should be a nondissipative largely adiabatic diffusive transport process which is followed by extraction into vacuum. A novel heat extraction mechanism for future cooling applications is thus anticipated.

0631: Endoscopic Ultrasound- Past, Present and Future

Endoscopic ultrasonography(EUS) has been introduced in 1979 by Green using the linear array system of 10 MHz in frequency. Although the system showed good image resolution, it was difficult to apply for human use because of the rigidity and length of the scan head. In 1980, Drs. Fukuda, Hirata, Sapporo Medical College and, Baba from Olympus Co. have introduced the radial scanning ultrasonic endoscope manufactured in collaboration with Olympus Co. Because of the short hard tip to scan the GI tract from inside the GI tract, it was easily inserted via mouth and esophageal tract and was possible to obtain 360 degree circular tomograms by US frequency of 7.5 MH or higher. Mucosal layering structures could be identified without difficulty. A part of these findings were reported in WFUMB Congress in Sydney in 1985. Shortly after that, a digital array scanner was introduced for biopsy by needle aspiration. Another development was the fine tip scanner of small caliber together with the use of standard endoscope. The first stage EUS equipment was further developed to a variety of models with increase of US frequency, to make easier to handle even within esophageal or colonic lumen as well. Almost 25 years elapsed since its introduction, and a variety of commercial equipments have been introduced. The use of EUS in general was, however, limited mostly to diagnostic use of ulcerating or mass lesions of the GI tract. Besides these uses for diagnostic purposes, the more direct practical applications are emerging in treating early stage gastric cancer, the most actively pursued subjects at present. The current developments are the removal of mucosal and submucosal gastric carcinomas by means of endoscopic mucosal resection, EMR, and endoscopic submucosal dissection, ESD, without laparotomy. Current developments will be discussed in detail.

Identifying Hydroxyls on the TiO2 (110)−1 × 1 Surface with Scanning Tunneling Microscopy

We present the investigations of hydroxylated TiO2 (110)−1 × 1 surfaces using scanning tunneling microscopy (STM). It is observed that in topographic images the protrusions of hydroxyls (OH) on TiO2 (110) surfaces are dependent on the tip−sample distance in STM measurements at room temperature. In comparison with those of the fivefold coordinated Ti atoms and the oxygen vacancies, the relative apparent height of OHs becomes smaller and smaller with decreasing tip−sample distance by changing the imaging conditions. The OHs even become invisible in much shorter tip−sample distances. Reversibly, the OHs are almost completely recovered when the imaging conditions are restored. It suggests that the OHs may be identified by varying the imaging conditions in STM measurement.

Fano–Kondo spin filter

The spin-dependent scanning tunneling spectrum generated by a ferromagnetic tip on a metallic host with a Kondo adatom is discussed. The combined effects of the Kondo screening, quantum interference, and tip magnetism are studied. For short tip–adatom separations, the askew lineshape characteristic of quantum interference in Kondo systems is split into two spin components. For the majority-spin component, the Fano antiresonance is strongly enhanced. With the tip atop the adatom, a window of bias voltages is found in which the tunneling current is nearly 100% spin polarized. In the vicinity of a Kondo adatom, the ferromagnetic scanning tunneling microscope constitutes a powerful spin polarizer.

Ectomycorrhizal root tips in relation to site and stand characteristics in Norway spruce and Scots pine stands in boreal forests

Variations in ectomycorrhizal (EcM) short root tips of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) in 16 stands throughout Finland were studied, and their relationships with latitude, organic layer C:N ratio, temperature sum and foliage biomass were determined. There were no significant differences in EcM root tip frequency (number per milligram of fine roots) or root tip mass between tree species or between northern and southern sites. The EcM root tip number per unit area of the organic layer plus the 0-30 cm mineral soil layer varied between 0.8 and 2.4 million per m(2) for Norway spruce and between 0.7 and 2.9 million per m(2) for Scots pine, and it was higher in the northern Scots pine stands than in the southern Scots pine stands. Over 80% of the EcM root tips of both species were in the organic layer and the upper 0-10 cm mineral soil layer. We related EcM root tips to foliage mass because these two components are the most important functional units in boreal tree physiology. Both species, especially the Scots pine trees, had more EcM root tips in relation to foliage mass in northern Finland than in southern Finland. Scots pine trees had more EcM root tips in relation to foliage mass than Norway spruce in the same climatic region. The EcM root tip:foliage biomass ratio of Norway spruce was positively related to the C:N ratio in the organic layer, whereas that of Scots pine was negatively related to the temperature sum. The number of EcM root tips per milligram of fine root biomass was constant, implying that trees of both species increase nutrient uptake by increasing fine root production and hence their total number of EcM tips and the area of soil occupied by mycelia. Both tree species responded to nitrogen (N) deficiency by maintaining more EcM tips per foliage unit, and this may be related to a higher proportion of N uptake in an organic form.

Long term effect of liming and fertilization on ectomycorrhizal colonization and tree growth in old Scots pine (Pinus sylvestris L.) stands

In this study, we surveyed the long term effects of liming and fertilizing in old Scots pine stands on the ectomycorrhiza (ECM) colonization, tree growth and needle nutrient concentration 35 years later. Four mature stands of Scots pine on low productive mineral soil were limed in 1959 and 1964 with total doses of limestone ranging from 3 to 15 Mg ha−1 and fertilized with nitrogen (N) in 1970. Thirty-five years after the first liming treatment, all stands were analysed for tree growth and needle nutrient concentrations and two of the stands were also analysed for ECM colonization. ECM colonization increased significantly with liming from 61.5% in the control plots to 88% in the plot with the highest limestone dose. ECM colonization increased with increasing pH in the humus layer from 62% colonization at pH = 3.5 to 90% at pH = 6.5 and decreased with increasing amount of extractable phosphorus (P) in the humus. Liming did not affect the frequencies of different ECM morphotypes or dead short root tips, the fine root biomass or necromass. ECM colonization was uncorrelated with needle nutrient concentrations or tree increment. Liming did not significantly affect tree growth. However, nutrient concentrations of current-year needles were affected by prior liming. Ca concentrations in current-year needles increased from approximately 15 mg g−1 in control treatments to more than 30 mg g−1 in limed plots, whereas concentrations of Mn, Al, Fe, and in two stands, B, decreased due to liming. In conclusion, liming with doses up to 15 Mg ha−1 was detectable in stands 35 years after treatment. The liming significantly increased the ECM colonization of Scots pine fine roots, increased the needle nutrient concentration of Ca and decreased the needle concentrations of Mn, Al, and Fe.

Tension-free vaginal tape Secur hammock procedure: two additional cases of intraoperative bleeding

Dear Editor, Masata and colleagues [1] recently reported a case of severe bleeding following the use of tension-free vaginal tape (TVT) Secur (TVT-S) hammock (Ethicon Women Health, Sommerville, NJ, USA) for the treatment of stress urinary incontinence. The mini tape was used to avoid major complications, given the advantage of shorter length of the inserter, but 3 h after surgery, the patient developed a severe postoperative hemorrhage collecting in the Retzius space. The authors concluded that the scalpel-shaped tip of the inserter could have cut the fibres of the obturator muscle and advised that the best way to release the inserter without producing such complication was to hold the tape with thin scissors or with a small tampon. In our institution, we recently experienced two cases of intraoperative haemorrhages after five patients were treated with TVT-S procedure. Women were, respectively, 60 and 68 years old and required the procedure for the treatment of symptomatic urinary stress incontinence. No coagulopathies were present in the preoperative blood checks or were referred on history. In both cases, an intraoperative bleeding manifested after the scalpel-shaped tip of the inserter was introduced and perforated the right obturator muscle. Haemorrhages were immediately treated with prolonged intraoperative compressions of dressing gauzes and with vaginal packing for the following 24 h. In the early postoperative period, patients were carefully monitored, but did not develop any symptom of hypotension or pain in the abdomen. However, laboratory analyses revealed a loss of 2.6 and 3.2 U of haemoglobin between the preoperative (12.8 and 13.8 mg/dl) and postoperative values (9.6 and 11.2 mg/dl, respectively). Given the moderate haemorrhage and the asymptomatic clinical status, no ultrasound or computed tomography scans were performed, and patients were discharged home on the second postoperative day. After 1 month of follow-up, patients were still asymptomatic and incontinence symptoms were absent. We agree with Masata and colleagues that the most probable reason for intraoperative haemorrhages during the TVT-S procedure could consist in the large diameter of the inserter. In fact, although the new mini tape owns a short scalpel-shaped tip, useful to avoid major complications, it is unfortunately still too large to pass through the muscular fibres of the obturator muscles without cutting them, producing a diffuse oozing. Differently from Masata, the haemorrhages we experimented were less important and were treated with a conservative approach (prolonged compressions and vaginal packing). However, our cases further confirm that this complication can be present during TVT-S and should be taken into serious account by surgeons that believe this as a less invasive procedure for the treatment of stress urinary incontinence.

Advanced tip design for liquid phase vibration mode atomic force microscopy

We have fabricated polymer tips for atomic force microscopy in order to elucidate the effects of tip length and shape on cantilever vibration damping in liquids. The vibration damping is investigated by measuring the vibration amplitude of cantilevers as a function of tip–sample distance. The cantilever with a short tip provides a higher damping effect over long tip–sample distances. When the vibration amplitude was rescaled to show the effect of the cantilever width on oscillation damping, the vibration amplitude of cantilevers with various tip lengths was similarly obtained in a long distance range over 50 μm. This similarity is explained by an acoustic damping model in which an acoustic wave is generated by the cantilever. Finally, the results indicate a cantilever with a sufficiently long tip compared to the cantilever width can dramatically reduce the long-range damping effect in a liquid environment.

Dichotomization of mycorrhizal and NPA-treated short roots in Pinus sylvestris

Conifers like Scots pine (Pinus sylvestris) have a complicated root system consisting of morphologically and anatomically different root types, of which the short roots have a very limited ability to elongate. Short roots have an important role in nature since they are able to establish ectomycorrhizal symbiosis, in which the growth of fungal mycelium between the epidermal cells and in the intercellular space between cortical cells leads to formation of dichotomous short roots, which may, through further splitting of the meristem, form coralloid root structures. Dichotomous short roots have been suggested to result from changes in either auxin or ethylene concentrations due to the fungal growth inside the root. NPA, the inhibitor of polar auxin transport, enhances the dichotomization of P. sylvestris short root tips similarly to the fungal growth in the root, thus confirming that auxin plays a role in short root morphogenesis. Ethylene is also known to have an important role in the regulation of root morphogenesis. In future the research dealing with the root system and ectomycorrhiza development in P. sylvestris must take into account that both auxin and ethylene are involved and that there is no contradiction in obtaining the same phenotype with both hormones. The expression analysis of PIN proteins, auxin efflux carries, could give valuable information about the role of auxin transport in regulating the root growth and morphogenesis of coniferous root system and mycorrhiza.

Morphology, and Muscle- and Papilla-Volume Ratios, of the Tongue of Laudakia stellio (Agamidae, Squamata): A Histological and Stereological Study

We examined the histological structure of the tongue of Laudakia stellio, the starred agama lizard (Agamidae, Squamata), under light microscopy. We also investigated the muscle and papilla volume ratios, with volumes of each aspect of interest estimated according to the Cavalieri method. The macroscopically short, thick and muscle-rich front tip of the tongue of L. stellio does not show any bifurcation, and under light microscopy, the oval-shaped papilla-free front tip was seen to be covered by keratinized stratified epithelium. The dorsal and ventral parts were different, with the former partially covered by keratinized stratified epithelium and rich in secretory glands and secretory cells. The ventral part, which contained keratinized stratified cells, had a flat surface with no papillae. The dorsal surface of the anterior and posterior parts contained fungiform papillae, with the apical parts of these papillae containing minimal keratin; the interpapillar space was covered by keratin-free squamous stratified epithelium. The middle section of the tongue contained cylindrical-type papillae, with serous and mucous secretory glands and ducts at their base. Finally, the frontal and middle parts of the ventral and dorsal surfaces did not contain any taste buds, although there were some in the hind part of the dorsal surface. As morphometric estimates of volumes of the muscles and papillae, the mean volume ratios (relative to total tongue volume)+/-standard deviation were 0.66+/-0.03 and 0.33+/-0.03, with mean coefficients of error of 0.02 and 0.03, respectively.