Bundles Of Needles Research Articles

Structure and flexural properties of 3D needled carbon fiber reinforced carbon and silicon carbide (C/C-SiC) composites fabricated by gaseous and liquid silicon infiltration

3D needled carbon fiber reinforced composites (C/C-SiC) were fabricated by gaseous silicon infiltration (GSI) for different reaction times, followed by further densification with liquid silicon infiltration (LSI). The density, flexural modulus and flexural strength increased as a spatially connected SiC structure developed, but the flexural strength could be degraded by a long total reaction time. The composites all exhibited quasi-brittle fracture with fiber bundle pull-out and interfacial debonding. Fracture could propagate within the needle bundles that were perpendicular to the tensile stress.

ENVIRONMENTAL ASSESSMENT OF THE STATE OF ATMOSPHERIC AIR OF COMMERCIAL HOLDINGS BY BIOINDICATING METHODS

Recently, among the wide arsenal of analytical, chemical, microbiological methods the problem of biological indication, that is, the assessment of the state of the environment by the reaction of living organisms has become urgent. The decrease in the morphometric indexes of acacia fruit may be due to a decrease in the number of seeds in the beans. The analysis of the number of seeds in the fruit showed a significant decrease in the investigated index in the territory of sanitary protection zone of the poultry farm in comparison with the control area. In acacia pods, which were selected on the experimental site of the pig farms, poultry farms and in the control area, the percentage of mature seeds is 27,8 %, 47,6 % and 74,5 %, respectively. Averaged data for 2015‑2016 years showed that in acacia pods, which were selected on the poultry farms, the percentage of mature seeds makes up 37,7 %, while in the pig breeding sector, 26,1 % at the same time in the control area it is 74,7 %, which indicates significant pollution of the air in the territory of SPZ. Consequently, it should be noted that the air from the emissions of livestock facilities is not sufficiently cleaned and adversely affects the reproductive system of plants. Bioindication of the atmospheric air using рine Pinus sylvestris L. The visual analysis of pine plants of the usual Pinus sylvestris L. showed that damage to the light green spots, necrotic points and drying occurs near the source of contamination with the needles. According to researches, a decrease in the absolute values of the length of the needles of Pinus sylvestris in the plantations with an approach to the livestock economy and with an increase in the level of environmental pollution is traced. There is also an increase in the number of needles in the shoots, which also indicates air pollution around the poultry farm. According to the research data, it was found out that in more polluted areas the bundles of needles are more closely aligned, and their number is 10 centimeters higher than in the clean zone. The minimum damage to the needle was found in the trees of the control site, and in other areas under investigation the damage to the needle was noted. With the distance from livestock farms, the number of needles on the shoots and the level of necrotic damage decreases, but the length, the width of needles, the weight of 1000 pcs of needles increase. In general, the morphometric indices of the needles of Pinus sylvestris usually vary in a wide range of numerical values, while the necrotic damage of the needle is the most informative bioindicative feature.

Controlling the yield behavior of fat-oil mixtures using cooling rate

The rheological behavior such as yielding of fat crystal networks are dictated by many variables. Among these variables, the shape of the constituent fat cluster is important yet relatively unexplored. In this work, we describe the rheological investigations of a fat-oil system which can be formulated to either contain bundles of needles or spherical clusters by controlling the cooling rate and fat concentration. Fat-oil mixtures containing high-fat concentrations exhibited weak frequency dependence of storage modulus (G ′) and loss modulus (G ″). The yielding behavior of the mixtures were investigated by large amplitude oscillatory shear (LAOS) rheology using strain and stress controlled modes. Lissajous-Bowditch plots and orthogonal set of Chebyshev polynomials were used to analyze the non-linearities associated with the yielded fat-oil mixtures. For a given fat concentration, the yield stress of fat networks obtained at low cooling rates (bundles of needles) were similar to that of networks obtained at high cooling rates (spherical clusters). However, after yielding, Lissajous-Bowditch plots suggested that the mixtures comprising of bundles of needles exhibited viscous-like behavior while the spherical clusters exhibited a plastic-like behavior. This was further supported by microscopy images of yielded fat-oil mixtures. Overall, for a given fat concentration, the two different shapes of fat clusters can give rise to networks of similar yield stress values but different behaviors after yielding.

Inactivation of Staphylococcus aureus in visible light by morphology tuned α-NiMoO4

Abstract α-NiMoO4 has been successfully implemented in different morphologies via microwave hydrothermal technique in presence of surfactants (Polyethylene Glycol, Sodium Citrate, and Sodium Dodecyl Sulfate). The inactivation of multidrug-resistant pathogens, Staphylococcus aureus (S. aureus) has been investigated in the presence of visible light as well as in dark. S. aureus was inactivated in 6 h under visible light irradiation. A slight inactivation of S. aureus was observed in dark. The generation of intracellular reactive oxygen species, ROS (O2 −, OH , and H2O2) in visible light was observed by using 2, 7-dichloro-dihydro-fluorescein diacetate (DCFA-DA) and nitro blue tetrazolium (NBT), which suggests the bacterial inactivation by ROS. Nanowires morphology of α-NiMoO4 exhibited effective bactericidal efficiency in visible light as compared to small bundle of needles, nanorod, large bundle of needles because of small size/diameter, toxicity, enhancement of ROS generation, and high BET surface area. The damages in the phospholipid layer present in the cell membrane of S. aureus were observed by FESEM analysis. Furthermore, the observation of DNA damages and protein degradation percentage give the evidence of ROS effect for deactivating the bacteria. So, this study offers new insight into the photocatalytic inactivation of multidrug-resistant microorganisms by morphology modulated visible light driven α-NiMoO4 photocatalyst.

Preparation of porcupine-like Bi2O3 needle bundles by anodic oxidation of bismuth

A new Bi2O3 structure resembling bundles of needles was prepared by anodic oxidation of a bismuth substrate in H2SO4 electrolyte followed by annealing in air. Needle growth occurred on the timescale of minutes. The resulting porcupine-like needle bundles were characterized using SEM and XRD before and after annealing. The as-grown needles consisted of bismuth aqua sulfate hydroxide; however, upon annealing at 250°C in air, tetragonal β-Bi2O3 was produced without any morphological change.

Development of an Economical DNA Delivery System by "Acufection" and its Application to Skin Research

Dysregulation of immune response in skin is associated with numerous human skin disorders. Direct transfer of immune-related genes into skin tissue is a fascinating approach to investigate immune modulation of cutaneous inflammation in mouse models of human diseases. Here we present a cost-effective protocol that delivered naked DNA in mouse skin and leads to transgene expression. The method is coined "acufection", denoting acupuncture-mediated DNA transfection. To perform acufection, mouse skin was first infused with DNA in phosphate-buffered saline (PBS) and then pricked lightly with a bundle of acupuncture needles to facilitate the absorption of DNA and transfection into cells. The plasmid DNA is presumably taken up by the keratinocyte and dendritic cells (DCs) in the skin and expressed into protein. Mechanical prick with the needles per se did not cause skin damage or induce keratinocyte activation. The expression of the transfected genes was detected in the skin at both transcriptional and translational levels following acufection for 2 days and maintained up to 7 days. The primary goal for the development of this acufection method was to investigate a previously undefined isoform of IL-15. Using this method, an alternatively spliced IL-15 isoform with partially deleted exon 7 (IL-15ΔE7) was expressed in the skin and subsequently treated with a Toll-like receptor 7 (TLR7) agonist, imiquimod (IMQ), to induce inflammation. Acufection-delivered IL-15ΔE7 in skin suppressed keratinocyte proliferation, epidermal thickness and neutrophil recruitment in IMQ-induced cutaneous inflammation. With increasing interest in identifying the regulatory mechanisms of cutaneous inflammation, the protocol described here provides a cost effective and versatile alternative to the gene gun system or microseeding for DNA delivery in vivo. It may potentially allow discovery of the function of a novel gene in the skin or for investigating new treatment for cutaneous diseases.

Development of an Economical DNA Delivery System by "Acufection" and its Application to Skin Research.

Dysregulation of immune response in skin is associated with numerous human skin disorders. Direct transfer of immune-related genes into skin tissue is a fascinating approach to investigate immune modulation of cutaneous inflammation in mouse models of human diseases. Here we present a cost-effective protocol that delivered naked DNA in mouse skin and leads to transgene expression. The method is coined "acufection", denoting acupuncture-mediated DNA transfection. To perform acufection, mouse skin was first infused with DNA in phosphate-buffered saline (PBS) and then pricked lightly with a bundle of acupuncture needles to facilitate the absorption of DNA and transfection into cells. The plasmid DNA is presumably taken up by the keratinocyte and dendritic cells (DCs) in the skin and expressed into protein. Mechanical prick with the needles per se did not cause skin damage or induce keratinocyte activation. The expression of the transfected genes was detected in the skin at both transcriptional and translational levels following acufection for 2 days and maintained up to 7 days. The primary goal for the development of this acufection method was to investigate a previously undefined isoform of IL-15. Using this method, an alternatively spliced IL-15 isoform with partially deleted exon 7 (IL-15ΔE7) was expressed in the skin and subsequently treated with a Toll-like receptor 7 (TLR7) agonist, imiquimod (IMQ), to induce inflammation. Acufection-delivered IL-15ΔE7 in skin suppressed keratinocyte proliferation, epidermal thickness and neutrophil recruitment in IMQ-induced cutaneous inflammation. With increasing interest in identifying the regulatory mechanisms of cutaneous inflammation, the protocol described here provides a cost effective and versatile alternative to the gene gun system or microseeding for DNA delivery in vivo. It may potentially allow discovery of the function of a novel gene in the skin or for investigating new treatment for cutaneous diseases.

Syntheses of needle-shaped layered perovskite (C6H5CH2NH3)2PbI4 bundles via a two-step processing technique

Similar to the three-dimensional perovskites, two-dimensional (2D) layered lead halide perovskites constitute a particular class of semiconductor materials in the family of perovskites. This article reports syntheses of needle-like bundles of 2D perovskite (C6H5CH2NH3)2PbI4 by a two-step processing technique. The concentration of C6H5CH2NH3I precursor has a great influence on the product, structural and compositional analyses prove the phase and stoichiometry of 2D perovskite (C6H5CH2NH3)2PbI4 with high crystallinity for the needle bundles synthesized with concentration of C6H5CH2NH3I higher than 25 mg/mL. Intensive studies on the growth mechanism of the products were carried out; we believe the involvement of C6H5CH2NH3+ group determines the layered structure and the final morphology of the products. Photoluminescence measurement show that the needles possess a band-edge emission peak centering around 540 nm and a narrow full width at half maximum of about 30 nm.

Phase Behavior and Micro‐Structure of Fat–Oil Mixtures: Engineering the Shape of Fat Clusters

AbstractThe mechanical properties of fat–oil mixtures are dictated by the morphology of the fat crystal network, which in turn is strongly affected by the processing conditions. In this work the effect of uniform (linear) cooling rates on the size and shape of tribehenin (fat) clusters in isopropyl myristate (oil) was studied. The state of the fat–oil mixtures was comprehensively analyzed by establishing pseudo‐phase diagrams via visual observations, brightfield and polarization microscopy at various cooling rates and fat concentrations. The microstructure of the constituent fat clusters undergo a shape transition from bundles of needles at low cooling rates to spherical clusters at high cooling rates. The network structures formed with these different shaped fat clusters were examined using rheology. At a given cooling rate, the storage modulus (Gʹ) of fat–oil mixtures versus fat concentration followed a power law relationship. For a given fat concentration, the fat crystal networks comprising of bundles of needles showed higher Gʹ values as compared to fat networks made of spherical clusters. While the fractal dimension of networks cooled at different cooling rates varied over a small range of 2.78–2.86, considerable change in the pre‐exponential factor (γ) was observed. The results show the critical importance of processing conditions on the shape and size of fat clusters and its impact on the rheological properties of the fat crystal network.

Fire Enhances Whitebark Pine Seedling Establishment, Survival, and Growth

AbstractPeriodic fire is thought to improve whitebark pine (Pinus albicaulisEngelm.) regeneration by reducing competition and creating openings, but the mechanisms by which fire affects seedling establishment are poorly understood. I compared seedling vegetation production in adjacent sites, one last burned in 1880 and the other in 1988, to test the hypothesis that recent fire increases whitebark pine seedling growth. I experimentally tested effects of fire on seedling recruitment and growth by planting seeds in prescribed burned and nearby unburned sites. Experimental results showed nearly three times greater seed germination and seedling survival in recently prescribed burn plots. Seedling vegetation production in the 1880 and 1988 burn sites were measured using stem diameter and number of new needle bundles. Stem diameter was approximately 26 % greater after the more recent fire in the 1988 burn site, and new needle bundle production was approximately 40 % greater in this site relative to seedlings in the adjacent site that was last burned in 1880. Seedling growth, measured as both above- and belowground biomass, was approximately 57 % greater in a recently prescribed burn site relative to growth in an adjacent site that was unburned since 1910. Higher growth rates after prescribed fire corresponded with greater soil NO3−and soil-available P concentrations relative to unburned controls. However, high N concentrations in leaves of seedlings in unburned plots indicated that whitebark pine seedlings were not N-limited. Higher P, increased light availability, and earlier snowmelt after fire may be important factors in general postfire success of whitebark pine.

Crystallographic Orientation of Cuttlebone Shield Determined by Electron Backscatter Diffraction

In common with many cephalopod mollusks, cuttlefish produce an internal biomineral buoyancy device. This cuttlebone is analogous to a surf board in shape and structure, providing rigidity and a means of controlling buoyancy. The cuttlebone is composed of calcium carbonate in the form of aragonite and comprises an upper dorsal shield and a lower lamellar matrix. The lamellar matrix comprises layers of chambers with highly corrugated walls. The dorsal shield comprises bundles of aragonite needles stacked on top of each other. Electron backscatter diffraction analyses of the dorsal shield reveal that the c-axis of aragonite is parallel with the long axis of the needles in the bundles such that any spread in crystallographic orientation is consistent with the spread in orientation of the fibers as they radiate to form the overall structure of the dorsal shield. This arrangement of c-axis coincident with the long axis of the biomineral structure is similar to the arrangement in corals and in contrast to the situation in the molluskan aragonite nacre of brachiopod calcite where the c-axis is perpendicular to the aragonite tablet or calcite fiber, respectively.

Raphides in the Uncalcified Siphonous Green Seaweed,Codium minus(Schmidt) P. C. Silva

The vacuole of utricles, the outermost cell layer of the siphonous green seaweed,Codium minus, had numerous single needles and needle bundles. The crystals composing each needle appeared arranged in a twisted configuration, both ends were pointed, and each needle was contained in a matrix or membrane; bundles of needles appeared enclosed by a matrix. Chemical and electron diffraction analysis indicated that the needles consisted of calcium oxalate. This is the first paper on terrestrial plant-like raphides in an alga.

The crystal structure of munakataite, Pb2Cu2(Se4+O3)(SO4)(OH)4, from Otto Mountain, San Bernardino County, California, USA

AbstractMunakataite, Pb2Cu2(Se4+O3)(SO4)(OH)4, has been found in association with a variety of rare secondary Te minerals at Otto Mountain, San Bernardino County, California, USA. It is very rare and occurs as subparallel bundles of blue needles up to 1 mm long. Electron microprobe analyses provided the empirical formula Pb1.96Cu1.60[(Se0.894+S0.11)∑1O3](SO4)[(OH)3.34(H2O)0.66]∑4- Munakataite is mono-clinic, space group P21/m, with cell parameters a = 9.8023(26), b = 5.6751(14), c = 9.2811(25) Å, β = 102.443(6), V = 504.2(2) Å3 and Z = 2. The crystal structure, solved by direct methods and refined to R1 = 0.0308 for 544 Fo > 4σF reflections, consists of Jahn-Teller-distorted Cu2+O6 square bipyramids. which form chains along b by sharing trans edges across their square planes. The chains are decorated by SO4 tetrahedra and Se4+O3 pyramids, which bond to apical corners of adjacent bipyramids. The chains are linked to one another via bonds to two different PbO9 polyhedra, only one of which exhibits one-sided coordination typical of Pb2+ with a stereochemically active 6s2 lone-electron-pair. Munakataite is isostructural with schmiederite and the structure is closely related to that of linarite.

Controlled Deposition of Calcite Crystals on Yttria-Stabilized Zirconia Ceramic Electrets

We demonstrated the crystallization of calcite on yttria-stabilized zirconia (YSZ) ceramic electrets using diffusion of (NH 4 ) 2 CO 3 vapor into a CaCl 2 solution with and without poly(acrylic acid) (PAA). On both negatively and positively charged surfaces in the absence of PAA, the precipitates were calcite crystals with the rhombohedra {10.4} plane oriented parallel to the electrets. This oriented growth was explained by the nucleation theory in the presence of an electric field. The calcite thin films with a fan-like fracture in a cross section formed on the electrets in the presence of PAA. The calcite aggregates consisting of the thin films were made of bundles of calcite needles either having a rough (00.1) top face with a triangular shape or having a faceted rhombohedral {10.4} top face. These calcite needles grew radially from PAA-Ca 2+ complex assemblies attached to the electrets with the growth direction being the c-axis. The effects of PAA addition and a surface electric field due to the electrets on calcite crystallization were apparent most remarkably on a negatively charged surface of the electrets. The surface electric field regulates not only CaCO 3 supersaturation in its vicinity but also the morphology of the PAA-Ca 2- complex assemblies anchored on the surface of the electret.

Tree-shaped C60/C60-ferrocene crystals by Kinetically Controlled LLIP Process

Among the one-dimensional C60 crystals, vertically aligned microtubes on the porous alumina substrates provide several interesting features including their well developed hexagonal cross sections and hollow internal structures. These characteristic structures of vertically aligned C60 microtubes are caused by their well developed crystals structures and can be predicted by classical nucleation and growth theory. Therefore, the variation of its chemical composition by doping or alloying or variation of kinetic environments during the growth can causes variety of structural changes from vertically aligned hexagonal microtubes. The morphology of vertically aligned C60 microtubes is modified by controlling kinetic factors and including of lattice defects. The controlling kinetic factors by modified injection mode of 2-propanol gives various inner structure of vertically aligned C60 microtubes such as filled inner structure, double walled inner structure and porous inner structures. The addition of lattice defects by inclusion of ferrocene doped C60 gives tree-shaped C60 crystals with many branches consisting of bundles of thin needles.

Cross-β Spine Architecture of Fibrils Formed by the Amyloidogenic Segment NFGSVQFV of Medin from Solid-State NMR and X-ray Fiber Diffraction Measurements

Over 30 polypeptides are known to assemble into highly ordered fibrils associated with pathological disorders known collectively as amyloidoses. Structural studies of short model peptides are beginning to reveal trends in the types of molecular interactions that drive aggregation and stabilize the packing of beta-sheet layers within fibrillar assemblies. This work investigates the molecular architecture of fibrils formed by the peptide AMed42-49 representing residues 42-49 of the 50 amino acid polypeptide medin associated with aortic medial amyloid, the most common form of senile localized amyloid. The peptide aggregates within 2 days to form bundles of microcrystalline-like needles displaying a high degree of order. Fibrils were prepared from peptides containing up to 23 13C labels, and the solid-state nuclear magnetic resonance (SSNMR) method rotational resonance (RR) was used to determine constraints on the distances between selective atomic sites within fibrils. The constraints are consistent with unbroken beta-strands hydrogen bonded in a parallel in-register arrangement within beta-sheets. Further RR measurements identify close (>6.5 A) contacts between residues F43 and V46 and between S45 and V46, which can only occur between beta-sheet layers and which are consistent with two principal models of beta-sheet arrangements. X-ray fiber diffraction from partially aligned fibrils revealed the classical amyloid diffraction pattern, and comparison of patterns calculated from model coordinates with experimental data allowed determination of a consistent molecular model.

Impact of three silvicultural treatments on weevil incidence, growth, phenology, and branch-level dynamics of Pinus strobus from large and small populations

Our goal was to quantify tree- and branch-level components of growth response to three silvicultural treatments (STs), and weevil incidence in white pine ( Pinus strobus L.) from large, central populations in Ontario (ON) versus small, isolated populations in Newfoundland (NL). Light levels were 100%, 42.0%, and 20.4% transmittance for the full-sun, intermediate-shade, and high-shade STs. After 8 years, the overall incidence of weevil infestation was 42.1%, 23.4%, and 13.7% for the full-sun, intermediate-shade, and high-shade STs, respectively (P < 0.001). Weevil impact on total height and volume averaged –13.2% and –11.8%. Analysis of dominant lateral shoots showed that ON populations had 32% longer shoots than the NL populations. Bud set difference was a primary determinant of shoot-length growth differences between regions: Julian days 171 and 184 for the NL and ON populations, respectively. The primary determining factors related to shoot length were the number of needle bundles and region, driven by light levels and day length, respectively, and the internode length, probably through inbreeding effects. Total height and diameter showed a positive curvilinear relationship to light level. To maximize fitness, NL conservation strategies should also now consider introducing adaptive trait variation in the context of anticipated climate change.

Microwave-Assisted Synthesis of Magnetic Ni Wire from a Metal−Organic Precursor Containing Ni(II) and Triethanolamine

A novel approach is proposed to synthesize Ni wire by microwave (MW) heating of the preorganized rod microstructure of crystal consisting of Ni2+ ions and triethanolamine (TEA). Field emission scanning electron microscopy (FESEM) studies of the Ni-TEA crystal reveal that TEA molecules lead to the formation of sub-micrometer-sized needle bundles that appear as a sheaf of straw tied in the middle. The organized structure stems from the hydrogen bonding, which is evident from single crystal X-ray diffraction and infrared spectroscopic (IR) studies. Microscopic studies using scanning electron microscopy, transmission electron microscopy, and atomic force microscopy show that nanoparticles of ∼12 nm are connected to each other and build the equilibrium wire structure. Thermogravimetric analysis-differential thermal analysis experiments in association with X-ray diffraction studies provide direct evidence that microwave irradiation plays a crucial role in stabilizing the pure Ni phase. The high blocking tempera...

Creation of calcite hollow microspheres with attached bundles of aragonite needles

AbstractNovel calcite hollow microspheres attached with bundles of aragonite needles have been synthesized via a simple precipitation reaction of aqueous solutions of CaClB2B and NaB2BCOB3B in the presence of MgP2+P ions at room temperature. The experimental results revealed that an appropriate molar ratio of [MgP2+P]/[CaP2+P], pH value of the solution and aging time are crucial for the formation of the unusual hierarchical CaCOB3B superstructure. A possible growth mechanism is proposed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Growth and luminescence properties of micro- and nanoneedles in sintered CdSe

Sintering CdSe powder under argon flow at temperatures in the range 800–900 °C produces the formation of needles on the sample surface. Bundles of parallel needles of a diameter of about 50 nm give rise to a domain-like appearance in the sample. In addition, rods and needles with a wide range of dimensions up to several microns appear distributed in the surface. The influence of ball milling of the starting powder on the formation of the needles is investigated. Cathodoluminescence in the scanning electron microscope has been used to characterize the sintered samples.