Diamond-shaped Research Articles

Molecular response of gall induction by aphid Schlechtendalia chinensis (Bell) attack on Rhus chinensis Mill

ABSTRACTHorned gall is named after its shape of irregular diamond, and is induced by the fluid-feeding aphid Schlechtendalia chinensis (Bell) attacks on the leaflets that are located in the branchlets of Rhus chinensis Mill., which is enriched in gallotannin and can be widely used in medicine and the food industry. To explain the molecular mechanism of gall development, we performed transcriptome analysis by Illumina deep sequencing and digital gene expression of four tissues, including galls, leaves that grew on the same branch as the gall taken (GL), leaves from a branch without any gall (LW), and leaves from a tree without any gall (CL). Differentially expressed genes abundantly enriched in the biosynthesis of secondary metabolites, plant–aphid interactions, and plant hormone signal transduction were highly expressed in galls compared with GL and LW. Phytohormone signal transduction, dominated by IAA and ABA, coordinates primary and secondary metabolism and thus induces gall induction and development after attack by aphids. This study provides a theoretical basis for the genetic improvement and processing of gallnut resources.

Solder Volume Effect on Interfacial Reaction between Sn-Ag-Cu/ENImAg Substrate

The purpose of this study is to investigate the effect of solder volume on interfacial reaction during reflow soldering between Sn-3.0Ag-0.5Cu (SAC305) and Sn-4.0Ag-0.5Cu (SAC405), and electroless nickel/immersion silver (ENImAg) surface finish. Different solder balls with sizes of 300μm, 500μm and 700μm diameters were used. The characteristics of intermetallic compound (IMC) were analysed by using field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), optical microscope and energy dispersive x-ray (EDX). After the plating process, the result showed that ENImAg surface finish was free from black line nickel. After reflow soldering, a thin layer Ni3P or P-rich layer was formed. The result also revealed that an IMC layer was formed at the interface of (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 as well as Ag3Sn platelet. In term of morphologies, the grains type of IMC layer appeared as chuck, needles, rode, plate, diamond and bar shape. The result also indicated that, the solder volume can influence the IMC thickness, where the smaller size of solder balls produced a thinner IMC layer compared with a larger solder ball during the reflow soldering process. Meanwhile, a total of the IMC thickness for SAC305 was thinner than SAC405 solder ball.

In vitro effects and mechanisms of lycopene in MCF-7 human breast cancer cells.

Breast cancer adversely affects the health status of women; therefore, the prevention and treatment of breast cancer is of critical importance. Lycopene is known to possess several biological effects such as removal of free radicals, alleviation of biological oxidative injury, and inhibition of tumor growth. In this study, we aimed to illustrate the effect of lycopene on tumor cell proliferation and modulation of cancer progression as well as its possible underlying mechanisms in human breast carcinoma cell line MCF-7 in vitro. MCF-7 cells were treated with different lycopene concentrations for 24, 48, and 72 h. Light field microscopy was used to observe cell morphology. MTT assay was used to determine the effect of lycopene on MCF-7 proliferation. Flow cytometry was employed to evaluate cell apoptosis. Real-time quantitative polymerase chain reaction was performed to detect the expression of p53 and Bax. Under microscopic examination, the untreated MCF-7 cells appeared to have a diamond or polygonal shape. Lycopene treatment resulted in cell shrinkage and breakage, whose severity increased in a dose and duration dependent manner. In addition, reduced cell proliferation and increased apoptosis (P < 0.05) were observed using MTT assay and flow cytometry, respectively. Moreover, lycopene could also upregulate the expression of p53 and Bax mRNAs in MCF-7 cells. In conclusion, lycopene inhibits proliferation and facilitates apoptosis of MCF-7 cells in vitro, possibly by regulating the expression of p53 and Bax.

Comparative evaluation of orthodontic bracket base shapes on shear bond strength and adhesive remnant index: An in vitro study.

BackgroundThe objective of this study was to evaluate the effect of orthodontic bracket base shape on shear bond strength and adhesive remnant index.Material and MethodsIn this in vitro study using 140 bovine incisors, shear bond strength (SBS) of brackets with different base shapes (rectangle, flower, round, heart, diamond, star, and football) were measured with an Instron testing machine and tested until bond failure. Adhesive Remnant Index (ARI) scoring was evaluated after debonding to evaluate the location of bond failure. Descriptive and one-way ANOVA post-hoc Tukey statistical analyses were performed with a statistical significance set at p≤0.05.ResultsStatistically significant difference in mean SBS in Newtons was observed for multiple base shapes (p<0.05). The highest mean SBS (N ± SD) was observed in football and flower base shapes (73.83 N ± 53.46; 65.82 N ± 37.89 respectively); the lowest mean was observed with diamond and heart shapes (30.51 N ± 11.73; 33.28 N ± 16.89 respectively). When reported in Megaspascals, statistically significant difference was observed for rectangle base shape (3.54 MPa ± 2.69) when compared to all other base shapes.ConclusionsBracket base shape has an effect on SBS. Higher SBS (N) for rectangle, flower, and football base shape indicates even stress distributions throughout the bracket base. Base shape with a pronounced converging tip over the axial plane may contribute to the reduction in SBS due to increased peak stress concentration resulting in bond failure. Key words:Shaped brackets, Shear bond strength, Adhesive remnant index, WildSmiles®.

Vocal Cord Dysfunction after an Inhalation Exposure

The manuscript embodies case material and the author’s extensive personal experience to address a perceived or actual airborne exposure when incorrectly judged as due to intrathoracic/lung damage when in reality the outcome is the more innocuous extrathoracic/upper airway’s vocal cord dysfunction (VCD). Because of the conviction of possible lung injury, the individual applies the fetal protective glottic closure reflex to counteract an odorant cue instigating acute VCD. Breathing against an obstructed glottis as well as hyperventilation from anxiety, panic and/or fear of personal harm worsens the laryngeal spasm. Spirometer shows flattening of the inspiratory loop of the flow-volume curve and endoscopy, while not done, would reveal adduction of the anterior two-thirds of the vocal cords with posterior chinking creating a diamond shape configuration. Successful therapy and management of VCD requires a speech therapy approach rather than physician prescribed medications.

Active learning in neuroscience: a manipulative to simulate visual field defects.

prevalent in 20–57% of stroke patients, visual field defects have been shown to impact quality of life. Studies ([8][1]) have shown increased risk of falling, ambulatory difficulties, impaired reading ability, and feelings of panic in crowded or unfamiliar places in patients with visual field

Decision-making of alternative pylon shapes of a benchmark cable-stayed bridge using seismic risk assessment

One of the main applications of seismic risk assessment is that an specific design could be selected for a bridge from different alternatives by considering damage losses alongside primary construction costs. Therefore, in this paper, the focus is on selecting the shape of pylon, which is a changeable component in the design of a cable-stayed bridge, as a double criterion decision-making problem. Different shapes of pylons include H, A, Y, and diamond shape, and the two criterion are construction costs and probable earthquake losses. In this research, decision-making is performed by using developed seismic risk assessment process as a powerful method. Considering the existing uncertainties in seismic risk assessment process, the combined incremental dynamic analysis (IDA) and uniform design (UD) based fragility assessment method is proposed, in which the UD method is utilized to provide the logical capacity models of the structure, and the IDA method is employed to give the probabilistic seismic demand model of structure. Using the aforementioned models and by defining damage states, the fragility curves of the bridge system are obtained for the different pylon shapes usage. Finally, by combining the fragility curves with damage losses and implementing the proposed cost-loss-benefit (CLB) method, the seismic risk assessment process is developed with financial-comparative approach. Thus, the optimal shape of the pylon can be determined using double criterion decision-making. The final results of decision-making study indicate that the optimal pylon shapes for the studied span of cable-stayed bridge are, respectively, H shape, diamond shape, Y shape, and A shape.

Surface Finishing on Arc-Shaped Inner Surface by Ultraviolet Assisted Polishing

Recently, diamonds have been utilized gradually for sliding parts and wear-resistant parts because of their excellent properties. The shape of diamond applied to these parts is not only plane but also arc-shaped inner surface. Therefore, development of diamond polishing technology is required. In this study, ultraviolet assisted polishing was thought to develop to polish polycrystalline diamond (PCD) on arc-shaped inner surface. The authors investigated effect of ultraviolet radiation on polishing efficiency and surface roughness. As a result, the surface roughness Ra of PCD showed less than 15 nanometers. In addition, polishing efficiency was improved about 30 percent due to ultraviolet assisted polishing.

Influence of etch pit development on the surface area and dissolution kinetics of the orthoclase (001) surface

The (001) orthoclase surface was dissolved at 180°C and at far from equilibrium conditions with an alkaline solution (pH180°C=9) in a titanium open flow reactor. Vertical scanning interferometer (VSI) and atomic force microscope (AFM) surface monitoring were periodically used during the reaction process in order to quantify the surface topography evolution. The dissolution of the (001) orthoclase face occurs with the formation of diamond shape etch pits. Diamond pit diagonals are parallel to the [100] and [010] axes, and the pit walls are parallel to (6 5 6), 65¯6, (6¯511) and 6¯5¯11 planes. The etch pit size and global surface retreat of the (001) surface were found to increase linearly with time. Based on statistical treatments of etch pit development monitoring by AFM, we designed a numerical model aimed at reproducing and quantifying the total surface evolution. Numerical results show that the stabilization of etch pits doubles the calculated dissolution rate, partly due to the intrinsically higher reactivity of pit walls, consistent with a dissolution process in line with the periodic bond chain (PBC) theory. In addition, normalizing the dissolution rate by the initial surface area of the (001) orthoclase surface induces a 20% overestimation of the calculated dissolution rate, while the total surface area of the dissolving face reaches a steady state after a few days of reaction. Additional simulations conducted to assess the impact of defect parameters revealed a weak dependence of the dissolution rate on dislocation density, consistent with previous experimental observations. Overall, the combined effect of the various defect parameters does not affect the dissolution rate by more than an order of magnitude, and probably contributes to a moderate extent to the dispersion of mineral dissolution rate data reported in the literature.

SPH and FE coupled 3D simulation of monocrystal SiC scratching by single diamond grit

An investigation was carried out to study the material removal modes in single diamond grinding of monocrystal SiC. In order to reveal the influences of diamond shapes on the removal regions of SiC, six diamonds of different shapes were used for scratching. Three shapes - cube, rectangular pyramid, and cubic octahedral were chosen to simulate ideal diamond shapes, whereas cone, ball, and triangular pyramid were used to express wear diamond shapes. Through combining two different simulation methods - FEM and SPH, the material removal process was simulated respectively for the grinding of SiC with single diamond grit of different shapes. A grinding test was also carried out for the diamond of cone shape in order to check the validity of simulation. It was shown that the simulation results agree basically well with the corresponding experimental results. Therefore, the influences of the different diamond shapes on the removal modes of SiC were analyzed and discussed mainly based on the simulation. The scratching length and the ratio of width to depth of the groove generated in scratching were used as the parameters to discuss the influence of diamond shapes. The forces in grinding with different diamond grits were also analyzed.

Microstrip antennas for X‐band and MM‐wave frequencies based on diamond shape defected ground structure and size extension method

ABSTRACTA diamond shape defected ground structure (DGS) is deployed on a higher mode rectangular microstrip patch antenna (RMPA) to improve the antenna return loss bandwidth and fabrication tolerance at X‐band and millimeter wave (mm‐wave) frequencies. The DGS dimensions have been analyzed to study their effects on the antenna's performance. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2836–2841, 2016

Diamond Shaped Frequency Reconfigurable Microstrip Patch Antenna

In this paper we proposed a design of diamond shaped frequency reconfigurable microstrip patch antenna by altering the physical structure of the antenna. The design consists of two triangular shaped patches with a gap. The triangular shaped patches can be connected or disconnected by using Radio Frequecncy Micro Electro-Mechanical System (RF MEMS) switch. By making the switches OFF / ON, the length of radiating part of the patch antenna can be varied and thus antenna can be tuned to different frequencies from 7.38 GHz to 7.58 GHz. Keywords: Diamond Shape, Equilateral Triangle, Frequency Reconfigurable, Microstrip Patch Antenna, Radio Frequecncy Micro Electro-Mechanical System (RF MEMS) Switch.

Contact-Free Templating of 3-D Colloidal Structures Using Spatially Nonuniform AC Electric Fields.

The formation of ordered and regularly shaped structures of colloidal particles with the aid of spatially nonuniform electric fields is a modern research area of great interest. This work illustrates how alternating current (AC) electrokinetic effects (dielectrophoresis, electroosmosis) can serve as contact-free templates, inside which colloidal microspheres can assemble into a variety of shapes and sizes. We show how three-dimensional colloidal structures of square, circular, and diamond shape of many tens of micrometers in size can be reproducibly formed with a single set of quadrupolar microelectrodes. Numerical simulations performed help to explain the role of AC electroosmosis and AC dielectrophoresis on the shaping of these structures as a function of applied voltage and frequency. We also demonstrate how the templating repertoire is further enhanced with the simultaneous application of a second, individually controlled AC electric field, which enables a variety of asymmetric colloidal structures to be produced using the same set of quadrupolar microelectrodes. As the preservation of shape and size of such electric-field templated structures after medium evaporation still remains a big challenge, here we also report on a novel method that permits the stabilization and isolation of these particle assemblies through medium gelation and subsequent hydrogel removal with a UV/ozone treatment.

Flux trap effect study in a sub-critical neutron assembly using activation methods

ABSTRACTThe neutron flux trap effect was experimentally studied in the subcritical assembly of the Atomic and Nuclear Physics Laboratory of the Aristotle University of Thessaloniki, using delayed gamma neutron activation analysis. Measurements were taken within the natural uranium fuel grid, in vertical levels symmetrical to the Am–Be neutron source, before and after the removal of fuel elements, permitting likewise a basic study of the vertical flux profile. Three identical flux traps of diamond shape were created by removing four fuel rods for each one. Two (n, γ) reactions and one (n, p) threshold reaction were selected for thermal, epithermal and fast flux study. Results of thermal and epithermal flux obtained through the 197Au (n, γ) 198Au and 186W (n, γ) 187W reactions, with and without Cd covers, to differentiate between the two flux regions. The 58Ni (n, p) 58Co reaction was used for the fast flux determination. An interpolation technique based on local procedures was applied to fit the cross sections data and the neutron flux spectrum. End results show a maximum thermal flux increase of 105% at the source level, pointing to a high potential to increase in the available thermal flux for future experiments. The increase in thermal flux is not accompanied by a comparable decrease in epithermal or fast flux, since thermal flux gain is higher than epithermal and fast neutron flux loss. So, the neutron reflection is mainly responsible for the thermal neutron increase, contributing to 89% at the central axial position.

Experimental study on thermal performance of micro pin fin heat sinks with various shapes

This paper presents a visualization experimental study on the heat transfer characteristics of various shapes of micro pin fins, including the circular, ellipse, diamond, square and triangle shape micro pin fin arrays with various equivalent diameters and pin fin density. The influences study of different sizes and shapes of pin fin on Nusselt number and heat transfer coefficient have been conducted. The results show that with the increase of the flow rate, the temperature of the bottom of the experimental section decreases. And the Nusselt number of different shapes of micro pin fins increases with the increase of Re. In which, the heat transfer performance of the ellipse shape pin fin appears better among the other shapes of pin fins. However, the higher pin fin of the ellipse shape density leads to a weaker flow performance. Besides, the micro-scale heat transfer correlation between the Nusselt number and the Reynolds number is fitted based on the experimental data.

Pharmacotherapies for nicotine addiction in adults and adolescents

The prevalence of tobacco use has declined substantially in the past few decades, yet it remains the leading cause of preventable death globally. Smoking frequency in adolescents is also alarming and is often associated with greater susceptibility to health problems in their adult lives. Unlike the extensive body of literature that exists for adults, research on smoking cessation approaches for adolescents is scarce. This review discusses current pharmacological and psychosocial interventions available for both adults and adolescents. Anti-smoking medications approved for adult smokers are either nicotine based (i.e., nicotine patch, gum, inhaler, nasal spray and lozenges) or non-nicotine based (i.e., sustained-release bupropion and varenicline), all of which improve abstinence by acting on nicotinic acetylcholine receptors (nAChRs) in the brain. Non-pharmacological interventions targeting the psychosocial aspects of smoking addiction include brief counselling, cognitive-behavioural therapy, motivational interviewing, contingency management, relapse-prevention strategies, social influence and mobile phone-based programs.

Effect of in situ synthesized SiC whiskers and mullite phases on the thermo-mechanical properties of Al2O3–SiC–C refractories

The Al2O3–SiC–C refractory samples were prepared from raw materials of calcined bauxite, brown fused alumina, tabular alumina, flake graphite, silicon carbide and metallic Si powders. The Fe2O3 powders were used as additive and the phenolic resin was applied as binder. The effects of calcination temperature on microstructural evolution and thermo-mechanical properties of the samples had been studied. Thermodynamic calculation of Al–Si–O–C systems shows that both mullite and SiC were as equilibrium phases after coking at elevated temperatures. The experimental results indicate that the mullite whiskers with large aspect ratio were formed after fired at 1000°C in a coke bed. When the temperature was raised to 1400°C, a new phase of SiC whiskers was formed in addition to the mullite whiskers. Morever, a large number of the mullite platelets with diamond shape were generated. The property tests show that as the firing temperature rose from 1000°C to 1400°C, the value of cold modulus of rupture (CMOR) was increased by 57.1% to 8.2MPa, and the cold crushing strength (CCS) was raised from 47.5MPa to 54.8MPa; also, the flexural modulus (FM) and load displacement were almost 30% and 20% increased respectively. It is also found that the hot modulus of rupture (HMOR) measured at 1400°C reached the maximum value of 8.1MPa after firing at 1000°C. Furthermore, after three thermal shock cycles, the residual strength ratio of samples after cured at 200°C was only 47.5% while the value rose to 96.4% after fired at 1400°C. It is believed that the substantial enhancement in the thermo-mechanical properties of Al2O3–SiC–C refractory samples under room and elevated temperatures could be attributed to the synergistic effect of in-situ formed SiC whiskers, mullite whiskers and diamond-shaped mullite with plane structure.

Rotor Pole Optimization of Novel Axial-Flux Brushless Doubly Fed Reluctance Machine for Torque Enhancement

This paper presents an optimal design of the rotor pole in a novel axial-flux brushless doubly fed reluctance machine (AF-BDFRM), which features higher torque and power density than its counterpart radial-flux BDFRM. The rotor span and rotor overhang lengths were the optimized parameters, with the goals of improving torque density and improving the quality of the output power, i.e., reducing the torque ripple. The optimal design process was applied to obtain the optimized shape for maximizing torque density while minimizing torque ripple in a 16 kW machine. Then, the optimal design results were verified by means of the transient 3-D finite-element analysis. Furthermore, the results of the optimally designed rotor pole were compared with those of a previously developed diamond shape. Finally, a sample prototype of one HP was selected for testing, considering the manufacturing cost and available testing facilities to verify the proper working of the novel AF-BDFRM.

3D Buoyancy-Induced Flow and Entropy Generation of Nanofluid-Filled Open Cavities Having Adiabatic Diamond Shaped Obstacles

A three dimensional computational solution has been obtained to investigate the natural convection and entropy generation of nanofluid-filled open cavities with an adiabatic diamond shaped obstacle. In the model, the finite volume technique was used to solve the governing equations. Based on the configuration, the cavity is heated from the left vertical wall and the diamond shape was chosen as adiabatic. Effects of nanoparticle volume fraction, Rayleigh number (103 ≤ Ra ≤ 106) and width of diamond shape were studied as governing parameters. It was found that the geometry of the partition is a control parameter for heat and fluid flow inside the open enclosure.

Feasibility of using bulk metallic glass for self-expandable stent applications.

Self-expandable stents are widely used to restore blood flow in a diseased artery segment by keeping the artery open after angioplasty. Despite the prevalent use of conventional crystalline metallic alloys, for example, nitinol, to construct self-expandable stents, new biomaterials such as bulk metallic glasses (BMGs) are being actively pursued to improve stent performance. Here, we conducted a series of analyses including finite element analysis and molecular dynamics simulations to investigate the feasibility of using a prototypical Zr-based BMG for self-expandable stent applications. We model stent crimping of several designs for different percutaneous applications. Our results indicate that BMG-based stents with diamond-shaped crowns suffer from severe localization of plastic deformation and abrupt failure during crimping. As a possible solution, we further illustrate that such abrupt failure could be avoided in BMG-based stents without diamond shape crowns. This work would open a new horizon for a quest toward exploiting superior mechanical and functional properties of metallic glasses to design future stents. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1874-1882, 2017.