Tree-like Branches Research Articles

Hyper and multiple f-index of nano star dendrimers

Dendrimers are branching molecules that consist of a central part attached to tree-like branches which are repeatedly connected to each other. Topological indices of a molecular graph are real numbers associated with graphs, which represents some of the properties of the molecule. In this article, we obtaine precise formulas for the hyper F-index and multiple F-index of a number of nano star dendrimers.

Westward Drift of Ionospheric Plasma Irregularities over a Low to Mid-latitude Transition Region in Indian Sector

We report the observation of plasma depletions/plumes in the F region ionosphere over a low to middle latitude transition region in the Indian sector. The observation of these plasma depletions is based on the data obtained in May 2019 through the all-sky airglow CCD imager installed in the campus of University of Kashmir, Srinagar (34.12 °N, 74.83 °E, magnetic latitude 25.91 °N). The depletions on the two consecutive nights of 05 and 06 May 2019 are aligned along the North-South (N-S) direction and drift westward. Several depletion bands along with some enhancement bands are seen in the 630-nm airglow images throughout the two nights. The observed structures show certain characteristics similar to Medium Scale Traveling Ionospheric Disturbances (MSTIDs) but these airglow features are not completely periodic. Further, in the observed depletion bands some East-West asymmetries are observed along with the structured tree-like branches of the airglow depletions. Some depletion bands even bifurcate leading to the inference that the structures are signatures of plasma irregularities rather than the usual MSTIDs observed in low-mid latitude transition region. The westward drift of the depletions especially during geomagnetic quiet times over this region makes this study significant since it offers a possible evidence that shows extension of spread F irregularities from the mid latitude region to the low-mid latitude transition region. In this paper, we point out some possible mechanisms related to the occurrence of plasma depletions at this region and their westward movement during geomagnetic quiet times.

Crashworthiness analysis of bio-inspired fractal tree-like multi-cell circular tubes under axial crushing

This study proposes novel bio-inspired fractal multi-cell circular (BFMC) tubes for energy absorption. The inner structures of the proposed BFMC tubes were constructed based on the fractal tree-like forms found in many biological structures such as giant water lily and dragon blood tree. The crashworthiness performances of the proposed structures with different fractal orders and mass were numerically investigated. The numerical results indicated that the specific energy absorption (SEA) increased with the fractal order and the SEA of the 2nd-order BFMC tube was 35.43% higher than that of the conventional multi-cell circular tube. Furthermore, the complex proportional assessment (COPRAS) method was adopted to optimize the performance of the BFMC. The results demonstrated that the proposed structure with four number of tree-like branches and 2nd-order fractal provided the best performance. Finally, a theoretical derivation of the mean crushing force (MCF) was developed for the proposed tubes based on the simplified super folding element theory. The theoretical results of MCF agreed well with the numerical results. The findings of this study provide an effective guide for using the biomimetic approach with the fractal tree-like forms for the design of a multi-cell energy absorber with high energy absorption efficiency.

Tailoring Controllable Nanowire Morphologies Using a Multi-layer Porous Anodic Alumina Template for Technological Applications

Straight nanowires fabricated from single-layer porous anodic alumina (PAA) templates are known to be mechanically weak. To provide additional support, nanowires can be fabricated on multilayered PAA templates. In this work, Cu and Ni nanowires were fabricated using single-, double-, and three-layer PAA templates by pulse electrochemical deposition (PECD). The templates were made by anodizing Al-1 wt% Si and Al-0.5 wt% Cu thin films under different conditions. The morphologies of the PAA templates and fabricated nanowires were examined with scanning electron microscopy. The length of the nanowires was 3 μm, while the diameters ranged from 50 to 70 nm. The nanowires fabricated from a double-layered template (Al-0.5 wt% Cu/Al-1 wt% Si) were mechanically stronger with larger surface areas than those fabricated from an anodized Al-1 wt% Si template. The nanowires formed within the anodized Al-1 wt% Si layer had tree-like branches, while vertical nanowires with horizontal anchors were formed in the anodized Al-0.5 wt% Cu layer. The results also indicated that the volume expansion of the PAA template was controlled by depositing a Al-0.5 wt% Cu layer below the Al-1 wt% Si film. The Ni nanowires can be used as a platform for hydrogen production and in other technological applications.

Морфологічні особливості селезінки гусей

The spleen of 2-month-old clinically healthy geese of a large gray breed (n=5) has been studied. The material has been fixed in 10% aqueous solution of neutral formalin and embedded into paraffin. Serial histological sections have been stained with hematoxylin and eosin, fuchsin-aniline-blue-orange by Mallory, azur II - eosin. It has been established that the prevalent structures of the white pulp of the spleen of the 2-month-old geese are presented by periarterial and periellipsoid lymphoid sheaths. Periarterial lymphoid sheaths are detected as masses of lymphoid tissue around the pulpal arteries, most of which are oriented radially and form tree-like branches of the central arteries. The periellipsoid white pulp is represented by lymphoid sheaths along the penicillary capillaries. It occupies a significant area of white pulp and is light islets of mostly round and longitudinally convoluted form, which contain from 2 to 6 sections of penicillary capillaries, in places with their pronounced dichotomous branching. The periellipsoid white pulp in the spleen of birds is considered as the equivalent of the marginal zone of the lymphoid nodules of the mammalian spleen. Lymphoid nodules were detected in the amount of 6-8 in the area of the transverse section of the organ, namely, in the places of branching of the pulpal arteries into central ones. All compartments of the white pulp are connected with the arterial pulp channel. The architectonics of the pulpal part of the arterial bed on longitudinal sections of the spleen of geese has a pronounced main type of branching. 2-3 pulpal arteries depart from the trabecular artery, which are directed radially into the pulp, branching into the central arteries, and the latter into the penicillary capillaries. The mass of lymphoid tissue, concentrated around all the main branches of one pulpal artery, allows us to distinguish the morphofunctional units of the white pulp – segments, which indicates the segmental type of structure of the spleen parenchyma of geese. Parenchyma segments are surrounded by red pulp formed by pulpal cords with venous sinuses and pulpal veins.

Polyamidoamine (PAMAM) dendrimers synthesis, characterization and adsorptive removal of nickel ions from aqueous solution

Nickel is a toxic metal and present in the effluents of electroplating industries. Conventional methods to remove nickel are expensive and ineffective. Heavy metals can be easily adsorbed by dendrimers. Dendrimers are radially symmetric, nano-sized molecules with homogeneous, mono-dispersed and well-defined structures consisting of the tree-like branches, characterized by terminal poly functionality. The present study was focused on the synthesis of PAMAM dendrimers by divergent method and their use for the removal of nickel from aqueous solution. Characterization of synthesized dendrimers were carried out by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), UV-visible spectroscopy and zeta sizer analysis. Different parameters such as contact time, concentration of dendrimers, pH and metal concentration have been optimized. Therefore, equilibrium isotherms and adsorption kinetics were determined. Estimation of extent of metal removal was carried out by Atomic Absorption Spectroscopy. Results have revealed that PAMAM dendrimers could possibly be used for the removal of nickel from industrial effluents.

Networked Life.

Select works are part of a 365-day art project, Networked Life. For one year, I created an artwork every day in response to a network seen, experienced, or imagined. Works were mixed media and diverse, featuring paintings, drawings, sculptures, and found materials. This project provided an opportunity to examine networks across industries and disciplines, referencing both literal and abstract forms of networks. Each artwork contained hubs and links, clustering, and radial and tree-like branches.

Dendrimer Based Nanoarchitectures in Diabetes Management: An Overview.

Diabetes has turned out to be one of the biggest worldwide health and economic burdens, with its expanded predominance and high complexity proportion. The quantity of diabetic patients is expanding enormously around the world. Several reports have demonstrated the sharp increment in the sufferers. Stable and acceptable blood glucose control is fundamental to diminish diabetes-related complications. Consequently, ceaseless endeavors have been made in antidiabetic drugs, treatment strategies, and nanotechnology based products to accomplish better diabetes control. The nanocarriers pertaining hypoglycaemics provide improved diabetes management with minimum risk of associated side effects. Dendrimers have caught an incredible attention in the field of drug delivery and personalized medicines. Dendrimers are three-dimensional well-defined homogenous nanosized structures consisting tree-like branches. The present review highlights the different aspects of dendrimers including fabrication, surface engineering, toxicological profile as well as delivery of antidiabetic drugs for the effective cure of diabetes.

Fabrication of polyvinylidene fluoride tree-like nanofiber via one-step electrospinning

A novel polyvinylidene fluoride (PVDF) tree-like nanofiber was controllably fabricated via one-step electrospinning by adding certain amount of salt into PVDF solution. A possible mechanism for the formation of the tree-like nanofibers was proposed by analyzing high speed camera photos of the spin jet and the result showed that the formation of tree-like nanofibers was due to the splitting of jets. The effects of salt type, salt content and processing parameter on the content of tree-like branches were investigated. The electrospun nanofibers were characterized by field emission scanning electron microscopy (FE-SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD), pore size meter and mechanical properties measurement. It was found that the PVDF/TBAC tree-like nanofibers with improved crystallinity and mechanical strength. The decreased average pore size caused by the tree-like structure and the resistance to organic solvent, can make it as a potential candidate for membrane separation.

Evaluation of Biocompatibility of Capsaicin-Loaded Dendrimers on Zebrafish Embryos

Dendrimers are the nano-sized structures which consist of tree-like branches with many functional terminal ends and are the monodisperse macromolecules which contain symmetric branching units built around a small core molecule. The properties and the applications of these structures depend on the functional terminals. One of the important properties of Dendrimers is its solubility which improves the bioavailability of the insoluble drugs and used as a carrier for drug delivery. Capsaicin can be used against many kinds of cancers. In the present study, the dendrimers were synthesized and capsaicin was bound to it. The successful binding of capsaicin onto the dendrimers was confirmed by the fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectroscopy. The solubility was checked with various solvents and their biocompatibility was evaluated in zebra fish embryos. The results revealed that the prepared dendrimers were biologically compatible in the invivo conditions.

Interactions in dendronized polymers: intramolecular dominates intermolecular.

In an attempt to relate atomistic information to the rheological response of a large dendritic object, interand intramolecular hydrogen bonds and p,p-interactions have been characterized in a dendronized polymer (DP) that consists of a polymethylmethacrylate backbone with tree-like branches of generation four (PG4) and contains both amide and aromatic groups. Extensive atomistic molecular dynamics simulations have been carried out on (i) an isolated PG4 chain and (ii) ten dimers formed by two PG4 chains associated with different degrees of interpenetration. Results indicate that the amount of nitrogen atoms involved in hydrogen bonding is ~11% while ~15% of aromatic groups participate in p,pinteractions. Furthermore, in both cases intramolecular interactions clearly dominate over intermolecular ones, while exhibiting markedly different behaviors. Specifically, the amount of intramolecular hydrogen bonds increases when the interpenetration of the two chains decreases, whereas intramolecular p,pinteractions remain practically insensitive to the amount of interpenetration. In contrast, the strength of the corresponding two types of intermolecular interactions decreases with interpenetration. Although the influence of complexation on the density and cross-sectional radius is relatively small, interpenetration affects significantly the molecular length of the DP. These results support the idea of treating DPs as long colloidal molecules.

Linear Viscoelastic Response of Dendronized Polymers

We investigate the linear rheology of well-defined dendronized polymers (DPs). They consist of polymethacrylate backbones with tree-like branches (dendrons) of different generations, from zeroth to fourth, grafted at each monomer and a methyleneoxycarbonyl spacer between the polymerizable group and the dendritic substituent. The degrees of polymerization for the different generation polymers are almost constant, allowing for systematic studies as a function of generation. Because of the synthetic approach, these macromolecules possess tert-butoxycarbonyl (Boc) groups which promote hydrogen bonding, whereas the benzene groups allow for weaker bonding (π-stacking) as well. The master curves of frequency-dependent storage and loss moduli of these macromolecular structures were obtained via time–temperature superposition of dynamic frequency sweeps at various temperatures. To access slow relaxations, creep measurements were performed at long times and converted to frequency-dependent moduli. For the first generation, it was possible to detect relaxation processes suggesting an approach to the terminal regime (flow). On the other hand, the zeroth and second to fourth generation polymers exhibited a solid-like behavior throughout a wide range of frequencies. The fast relaxations reflect the coupling of segmental friction and hydrogen bonding and render the WLF-type analysis nontrivial. On the basis of the molecular structure of these unique materials as revealed by molecular dynamics simulations and complementary studies with their linear analogues poly(methyl methacrylate) and poly(tert-butyl)methacrylate, we propose that DPs resemble weakly interpenetrating elongated core–shell systems. As generation increases, their enhanced rigidity and intermolecular hydrogen bonding, which occurs primarily toward the outer surface of the DPs, appear to dominate the dynamics. PG0 is not a DP and has an open structure that promotes intermolecular bonding. These results provide design guidelines for ultrahigh-molecular-weight responsive polymers with possibilities for multifunctional substitution and tailoring Frheological response from liquid-like to solid-like.

DiI Staining of Fine Branches of Bonghan Ducts on Surface of Rat Abdominal Organs

Novel thread-like structures and corpuscles, designated Bonghan ducts (BHDs) and corpuscles (BHCs), are known to form a system of networked channels. Here, we tested the effectiveness of a fluorescent carbocyanine dye, DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate), in staining BHDs and BHCs. DiI solution was infused into a BHC on the surface of a rat abdominal organ at a steady rate and the resulting labeling of neighboring BHCs connected via BHDs was examined, as identified by the red fluorescence of DiI. BHDs diameters tapered away from BHCs and formed tree-like branches with fine arborizations embedded in the membranous tissues at their terminal parts. In the proximal parts, DiI fluorescence appeared as continuous lines within BHDs, but a large portion of BHDs remained unstained. In the distal parts of BHDs, discontinuous elongated DiI microparticles were identified along the sinuses within BHDs. The results showed that inner spaces within the BHDs allowed DiI to flow and that BHDs have tree-like branches and terminal arborizations. In conclusion, DiI can be used in visualizing BHDs fine structures.

Fine structure and formation mechanism of particulate phase‐inversion poly(vinylidene fluoride) membranes

AbstractThe structure and formation mechanism of a microporous phase‐inversion poly(vinylidene fluoride) (PVDF) membrane exhibiting a relatively loosely packed agglomerate of semicrystalline globules are explored. The membrane has been prepared by the coagulation of a solution of PVDF in dimethylformamide by the action of 1‐octanol, which is a soft nonsolvent. Experimental observations pertain to the globule surface, which is dominated by a grainy nanostructure; the globular interior, which exhibits a range of fine structures (e.g., twisted sheets and treelike branches); and the globule–globule connections, which exhibit a sheetlike or ropelike structure. On the basis of the observed structural details and phase diagram considerations, it is proposed that the membrane structure is the result of a unique combination of a polymer crystallization and a liquid–liquid phase‐separation process, with end‐result globular structural features of remarkable uniformity. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1578–1588, 2003

Significance of the smooth muscle cell component in Peutz-Jeghers and juvenile polyps

We have previously reported the presence of smooth muscle cells (SMCs) in the lamina propria of both tubular and villous adenomatous polyps. In the current study, we investigated the presence and distribution of SMCs with immunohistochemical techniques using anti-alpha smooth muscle actin and anti-desmin antibodies on a series of hamartomatous polyps. In five Peutz-Jeghers polyps, large tree-like branches of SMCs were observed, while in 13 juvenile polyps, rare elongated SMCs were found in the lamina propria, partially surrounding cystically dilated glands. Apart from the quantitative differences, the SMC distribution was similar in the two types of hamartomatous polyps and not dissimilar from the pattern described in neoplastic polyps. These findings make the category “juvenile polyp” less clear and its differentiation from other histologic types of polyp less sharp. Thus, the presence or absence of SMCs cannot form the basis of the differential diagnosis between adenomatous and hamartomatous polyps.

An Electron Microscopic Study of the Function of the Root Cells in the External Spiral Sulcus of the Cochlea

The ultrastructure of the area of the external spiral sulcus of the cochlea was studied in 15 hamsters. Intravital fixation with glutaraldehyde was followed by osmium citrate fixation and embedding in araldite. The endolymphatic surface of the external spiral sulcus is nearly completely covered by Claudius cells under which the root cells are situated. These epithelial cells are composed of bundles (roots), which protrude into the connective tissue of the spiral ligament in a tree-like fashion, forming primary, secondary, and tertiary branches. The basement membrane is a reliable landmark in this complex region, serving as a differentiating zone between the root cells and the mesenchymal tissue. Two different types of root cells are found. There are organelle rich "dark" cells and "light" cells which contain only a few cell organelles. All types of transitional forms between these two cell types are found, which can be interpreted as an expression of different metabolic activity of the same cell type. Between the root cells are seen extracellular clefts into which the "dark" cells, with their high synthetic and secretory activity, expel their secretions. These clefts lead to the endolymphatic space. A continuous production and secretion of part of the endolymph by the root cells is very likely. The anchoring of fibrils at the basement membrane of the root cell bundles, and their continuity with the basilar membrane leads to the assumption that this whole system may act as a mechanical pump. At high sound pressure levels, the strong vibration of the basilar membrane may lead to a locally and temporarily enhanced secretion of substances from the root cells into the cochlear duct.