Dumbbell Shaped Research Articles

Dumbbell Shaped Bi-Paddled Pectoralis Major Myocutaneous Flap (PMMF) for Composite Commissural Defects: A Defect Driven Modification

Pectoralis major myocutaneous flap (PMMF) has been a workhorse in orofacial reconstruction. Although microvascular tissue transfer has gained popularity in major tertiary centres, several infrastructural factors limit its use in many facilities, particularly in developing countries with high caseloads. Numerous modifications have been made to the PMMF since its inception. Here, we present a novel technique for reconstructing composite commissural defects with PMMF by modifying the skin paddle design to a dumbbell shape. Both ends of the paddle are used to line intraoral and extraoral defects, while the constricted middle portion recreates the commissure. We report the outcomes of a cohort of seven patients treated at our institution, describing the modified PMMF design, harvesting, and in-setting techniques used in oral carcinoma cases involving the commissure. We have detailed the study outcomes for each patient, including the various complications related to the flap, donor, and recipient sites.

Design and Analysis of Quad Dumbbell Shaped Directive UWB Antenna for Microwave Tumour Detection Integrated with Meander Strip Resonators

Design and Analysis of Quad Dumbbell Shaped Directive UWB Antenna for Microwave Tumour Detection Integrated with Meander Strip Resonators

Broadband all-metal reflective-mode geometric metasurfaces for visible multi‐functional wavefront manipulation

Visible light manipulation has become a well-explored subject over recent years owing to its fascinating prospect in the optical communication field. Nevertheless, the limitations imposed by materials inherent in natural hamper the progress of the optical devices. Here, a broadband reflective-mode all-metal geometric metasurface (GMS) capable of high-efficient circular polarization (CP) conversion and applicable for multi-functional wavefront manipulation was proposed and investigated numerically in visible region. The proposed all-metal GMS is comprised of the periodically arranged gold dumbbell-shaped (DBS) nanostructure with symmetrical square notch adhered on the gold substrate. Simulation results demonstrate that the cross-polarized reflection amplitude of the all-metal GMS for normal incident CP light is practically higher than 85% from 310 THz to 500 THz, and the full 2π phase shift in this frequency range can be acquired by varying oriented angle of the DBS nanostructure. As proofs of multi-functional wavefront manipulation devices, beam deflectors, reflective planar focusing metalens and vortex beam generators were constructed and demonstrated numerically with the all-metal DBS nanostructure based on geometric phase principle. Overall, the proposed GMS carries with it considerable advantages of compaction and high efficiency, thus possessing infinite potential in optical devices.

Analysis of RCC Building with Regular and Dumbbell Shaped Shear Wall in Different Types of Zones Using ETABS Software

Abstract: In structural engineering, a shear wall is a vertical element of a seismic force resisting system that is designed to resist in-plane lateral forces, typically wind and seismic loads. In many jurisdictions, the International Building Code and International Residential Code govern the design of shear walls. A shear wall resists loads parallel to the plane of the wall. Collectors also known as drag members; transfer the diaphragm shear to shear walls and other vertical elements of the seismic force resisting system. Shear walls are typically light-framed walls with shear panels, reinforced concrete walls, and reinforced masonry walls. The G+15 story structures situated in earthquake zones III, IV and V will be considered for study. All frames are designed under same gravity loading. Response spectrum method is used for seismic analysis. ETABS software is used and the results are compared. The results were obtained in the form of top story displacement, Story drift, Base shear and displacement

Magnetic resonance imaging features and clinical course of malignant melanotic nerve sheath tumors: single institution experience over two decades.

To evaluate MR features and clinical course of malignant melanotic nerve sheath tumor (MMNST), previously known as melanotic schwannoma and considered indolent and rarely metastasizing. This IRB-approved retrospective study searched 31 patients (20 male: 11 female, mean age 48; range 15-76) with histologically confirmed MMNST in a single tertiary cancer center over 22years. Pre-treatment MR was available in 12 patients and evaluated by two radiologists in consensus regarding lesion location, size, morphology, signal characteristics, contrast enhancement, local invasion, and presence of classic signs of peripheral nerve sheath tumors. Clinical outcomes, including local recurrence, metastasis, and survival, were examined in 12 patients for whom follow-up was available. The spine was the most frequent site (13/31) among all identified cases. In 12 cases with MR, lesions were well-circumscribed in 11/12 cases, with a mean size of 4.5cm (2.3-13.0cm). Ten of 12 cases showed T1 hyperintensity. In 5/9 spinal MRI, tumor involved multiple levels. All lesions showed contrast enhancement, and local bone invasion in > 50%. A dumb-bell shape was common to all spinal lesions. Classical signs of nerve sheath tumors were uncommon. Among 12 patients with a mean follow-up of 4.8years (range 1.3-10.2years), six were disease-free, while two had recurrence or metastases, and four had died of metastases. MMNST usually presents as a T1 hyperintense enhancing dumb-bell shaped mass in the spine. Multi-level involvement and bone invasion are common. MMNST is clinically aggressive with high rates of metastases and death.

A Dumbbell Shaped Piezoelectric Motor Driven by the First-Order Torsional and the First-Order Flexural Vibrations

A piezoelectric motor driven by the first-order torsional and first-order flexural (T/F) vibrations is designed, fabricated, and tested in this study. The actuating force is generated by the torsional vibration of the dumbbell-shaped vibrator, while the elliptical motion shape is adjusted with the flexural vibration. The rotor, pressed onto the vibrator’s lateral surface, is frictionally driven with the vibrator. Here, the torsional vibration, the shear modes of piezoelectric ceramics, and the driving method may contribute to high torque and high output power. To test the feasibility of our proposal, first, a prototype of the T/F vibrator is built and its vibration properties are explored. As predicted, the torsional and flexural vibrations are excited on the vibrator. Then, the load characteristics of the piezoelectric motor are investigated. The maximal torque, the no-load rotation speed, and maximal output power are 4.3 Nm, 125 r/min, and 16.9 W, respectively. The results imply that using the first-order torsional and the first-order flexural vibrations is a feasible method to achieve high torque and high output power of piezoelectric motors.

Facile Synthesis, Characterization, Anti-Microbial and Anti-Oxidant Properties of Alkylamine Functionalized Dumb-Bell Shaped Copper-Silver Nanostructures

Admirable studies have been established on the utilization of ligand-materials as bimetallic nanoparticles in the field of nanoscience and biotechnology. UV-Vis, XRD, HR-TEM, STEM-HAADF, EDS, FTIR, and DPPH analyses characterized the optical, structural, compositional morphological, and antioxidant properties of synthesized Cu-Ag nanostructures. The spectrum of UV-Vis exhibited absorption bands at 590 and 413 nm, which reflects the surface plasmon resonance of copper-silver nanostructures. Herein, our exploration of alkylamine stabilized copper/silver nanostructures while using hexadecylamine as capping material and their primary biomedical investigation on antimicrobial and antioxidant studies is reported. Cu-Ag bimetallic nanostructures were more effective against gram-negative bacteria E. coli and Klebsiella when compared to gram-positive bacteria. The antioxidant activity of Cu-Ag nanoparticles was comparable with Ascorbic acid.

Design of Dumbbell Shaped DGS-Notch Patch Antenna for Microwave Imaging System

In this paper, square Microstrip Patch Antenna with notch is designed with dumbbell shaped DGS for microwave imaging system. The antenna is designed on dielectric substrate, FR-4 with relative permittivity, ℇ r = 4.7 and thickness, 1.6mm. The dumbbell shaped DGS act as the resonant structures and is placed as the ground layer of the antenna. Different location and size of dumbbell shaped DGS are simulated and analyzed. The result of return loss, radiation pattern and antenna gain are simulated using Electromagnetic Simulation Tools, fabricated and measured using Wave and Antenna Training System (WATS 2002). The design shows better performance with return loss of -38.99 dB and higher antenna gain of 6.20 dB compare to the conventional design, with return loss of -30.21 dB and antenna gain of 5.48 dB respectively.

Research of Dumbbell Shaped DGS to Enhance The Bandwidth and Multiple Band Applications

A monopole microstrip rectangular patch with dumbbell shape slotted on ground for multiple band, enhance the bandwidth. The proposed antenna is fabricated on FR 4 epoxy material with electrical permittivity of 4.4 and magnetic permeability 1.The dimensions of proposed antenna are 70 x 50 x 1.6 mm3 and the dumbbell shape is slotted on ground of substrate which resonates at four different frequencies 5.9 GHz, 7 GHz, 8.7 GHz and 9.7 GHz. The proposed antenna has bandwidths of 200 MHz 300 MHz, 300 MHz, 300 MHz at four resonant frequencies The proposed antenna covers 4/8 GHz C band, 8/12 GHz X band and used in radar, satellite communications. The reflection coefficient (S11), radiation characteristics, peak gain and VSWR of designed antenna are described

2188 Off-label Use of Lumen-Apposing Metal Stent for Gastro-Jejunal Anastomotic Stricture Following Roux-en-y Gastric Bypass

INTRODUCTION: Roux-en-y gastric bypass (RYGB) is the second most common bariatric surgery performed after sleeve gastrectomy. A complication of this procedure is a gastrojejunal (GJ) anastomotic stricture. A lumen apposing metal stent (LAMS), which was initially used for draining pancreatic fluid collections/cystogastrostomy, is now being used in various locations throughout the gastrointestinal tract due to its novel dumbbell shaped design. In this case report we present a case of GJ anastomotic stricture successfully managed with LAMS after failure of serial balloon dilations. CASE DESCRIPTION/METHODS: A 51-year-old woman with a history of RYGB in 2008, complicated by recurrent stricture of her GJ anastomosis, presented for treatment options of her stricture. She had undergone dilations in the past with no change in her symptoms of daily vomiting. The patient requested a more definitive treatment. The patient was taken for placement of a LAMS endoscopically. Her stricture at the GJ anastomosis measured 7mm in diameter and <1 cm in length. A hydrophilic wire was inserted into the jejunum under fluoroscopic guidance. A 15mm LAMS was advanced over the wire into the jejunal lumen. Placement was confirmed with endoscope and fluoroscopic image. Finally, a 12-13.5-15 mm CRE balloon was advanced over the wire and used to dilate the lumen of the stent. The patient returned to the clinic 5 weeks later with complete resolution of her symptoms. She will have the stent removed in 2 weeks. DISCUSSION: GJ anastomoses can initially be managed with pneumatic dilations. However, this requires repeat interventions with limited success. A common alternative is the fully covered self-expanding metal stent (FCSEMS). The FCSEMS has a high rate of adverse events including stent migration, perforation, and recurrence of strictures after removal. A LAMS has a novel dumbbell shape design that prevents leakage and migration due to 24 mm anchoring flanges, while also being shorter and smaller than FCSEMS. Additionally, because of the dumbbell shape, when inflated with a CRE balloon, the risk of migration is very low. For these reasons, in addition to its expanding use within the GI tract, it was used in our patient with success. This case demonstrates another use for LAMS that is safe and effective in an expanding population.

Prediction of Mechanical Properties for Curved Dumbbell‐Shaped Specimen at Different Orientation Angles of Ring Hoop Tension Test

Manufacturing processes of polymeric plastic pipes play an important role and effect on their mechanical behavior. These processes cause a significant difference in the mechanical behavior between traditional tensile test specimens from the basic materials and final product of plastic pipes. The present study is focused on the mechanical behavior of ring specimens cut from pipes in the circumferential direction to obtain accurate materials design data during checking the quality of the final product for the plastic pipes. The experimental work is conducted at different crosshead speeds (VC.H = 10–1000 mm min−1) and different loading angles relative to the location of the dumbbell shaped (DBS) (α = 0°, 30°, 45°, 60°, and 90°) to study the mechanical properties of the ring hoop tension test (RHTT) specimens. The effect of loading angle of RHTT specimen is investigated at constant crosshead speed equal 50 mm min−1. The tensile test results show that the engineering hoop yield strength is maximized at loading angle, 90° for both single and double configurations compared with all loading angles at crosshead speed 50 mm min−1. The experimental results predict the yield point on the curved surface of DBS configuration based on the vertical displacement of the movable head for tensile testing machine.

How and where the mitral valve leaks in functional mitral regurgitation

Background and AimIt remains unknown how and where the mitral valve leaks in functional mitral regurgitation. The objective of the current study was to quantify the geometry and position of the leaflet free edges in order to reveal gapping mechanism of the mitral valve, and develop a plug technique to prevent mitral regurgitation. MethodsEight porcine mitral valves were sutured onto a dilated annulus in an in-vitro experiment to simulate valve closure at hydrostatic transmitral pressure. Eight sonocrystals were attached to the mitral valve leaflet free edges. Papillary muscles (PM) were adjusted to the normal position, and subsequently to positions of asymmetric and symmetric papillary muscle displacement. Sonocrystal positions were measured and analyzed. ResultsThe leaflet free edges in the central and medial regions moved medially, apically, and posteriorly from normal to asymmetric PM position. Gapping potential in the posteromedial region increased. Medial displacement of the free edges sometimes generated a gap in the anterolateral region in the asymmetric PM position. The leaflet free edges moved posteriorly and apically from the normal to symmetric PM position, and generated a dumb-bell shaped gap. ConclusionsAsymmetric PM position impairs the posteromedial coaptation region due to leaflet tenting, and compromises the anterolateral coaptation region due to medial leaflet displacement. The gaps include multiple sites along the coaptation line. Symmetric PM position impairs valve coaptation due to valve tenting only. The gap is a symmetrical dumb-bell shape. The findings are crucial for development of the plug technique to prevent mitral regurgitation.

Dynamics of driftless preconcentration using ion concentration polarization leveraged by convection and diffusion.

Over the past several decades, separation and preconcentration methods of (bio)molecules have been actively developed for various biomedical and chemical processes such as disease diagnostics, point of care test and environmental monitoring. Among the great developments of the electrokinetic method in a micro/nanofluidic platform is the ion concentration polarization (ICP) phenomenon, in which a target molecule is accumulated near a permselective nanoporous membrane under an applied electric field. ICP method has been actively studied due to its easy implementation and high preconcentration/separation efficiency. However, the dynamic behavior of preconcentrated analytes has not yet been fully studied, especially driftless migration, where the applied electric field is orthogonal to the direction of the drift migration. Here, we demonstrate anomalous shapes of preconcentrated analytes (either plug or dumbbell shape) and the morphologies were analytically modeled by the leverage of convection and diffusion migration. This model was experimentally verified with various lengths of DNA and the limiting cases (convection-free environment in paper-based microfluidic device and extremely low diffusivity of red blood cells) were also shown to confirm the model. Thus, this study not only provides an insight into the fundamental electrokinetic dynamics of molecules in an ICP platform but also plays a guiding role for the design of a nanofluidic preconcentrator for a lab on a chip application.

Radiation assisted synthesis of dumb bell shaped calcium hydroxide nanostructures from egg shells and study of its thermal and catalytic applications

In this work a novel, low-cost and simple method is used for synthesis of calcium hydroxide nanoparticles having dumb bell like morphology. The composition and purity of the product are analyzed by X-ray diffraction analysis. The morphology of the product is analyzed by scanning electron microscopy and transmission electron microscopy. The formation mechanism of dumb bell shape from trigonal unit cells is also proposed here. The thermal conductivity, thermal diffusivity and specific heat of product are measured in 303–533 K temperature range. Thermal conductivity increases from 0.49 to 0.69 W/mK with increase in temperature from 303 to 533 K. The thermal diffusivity decreases from 79.0 to 46.2 mm2/s with increase in temperature from 303 to 333 K and it increases from 46.2 to 53.2 mm2/s with increase in temperature from 333 to 533 K. Specific heat of product is sharply increased from 3.1 to 5.4 MJ/m2 K on increasing temperature from 303 to 333 K temperature. Moreover the physical and combustion characteristics of fuel (diesel) are studied at 0, 10, 20 and 40 ppm dosages of product. The calorific value of fuel is increased from 0.95 to 41.93 MJ/kg with increase in additive dosage from 0 to 40 ppm. Flash point and fire point of fuel are increased by 7.5 and 9.5 °C with addition of 40 ppm additive respectively. Specific gravity is increased from 0.1149 to 0.3472 g/cm3 by increasing the additive dosage from 0 to 40 ppm. Kinematic viscosity of fuel is increased from 2. 68 × 10−6 to 3.2 × 10−6 m2/s with increase in additive dosage from 0 to 40 ppm.

Mutual Coupling Reduction of MIMO Antenna for Satellite Services and Radio Altimeter Applications

Ground irregularities also known as defected ground structures (DGS) is a freshly presented innovatory way in designing of patch antennas to boost up the performance of antenna constraints. This study presents a novel proposal of ground irregularities or defected ground structure is proposed for suppression of mutual coupling effects among 2x1 multiple input multiple output patch array designed on Roggers Duroid 5880. The two adjacent M shape structures surrounding Dumbbell Shaped structure and sandwiched between Dumbbell shape patterns showed the significant level of surface wave suppression up to -42dB while maintaining the gain of 4.7dB and 5.6dBi of directivity. The patch array operates at 4 to 4.3GHz for Fixed and Radio satellite services (FSS) and (RSS) and radio altimeter application systems.

A compact planar ultra-wideband bandpass filter with multiple resonant and defected ground structure

A compact bandpass filter with dumbbell shape Defected Ground Structure (DGS) operating on ultra wide pass band (UWB – 3.1 to 10.6GHz) is proposed. It is based on hybrid microstrip coplanar waveguide (dual sided metal) structure. A Multiple Resonant Structure (MRS) is constructed using coplanar waveguide (CPW) planar transmission line. The MRS makes the resonance using quarter wavelength and half wavelength open-ended CPW. The equispaced three resonances at lower (3.1GHz), center (6.85GHz) and higher edge (10.6GHz) of the whole Ultra Wide Band is achieved using CPW MRS. To make the band as flat as possible, two more resonances are introduced using quarter wavelength microstrip patches on top of the commonly shared substrate, so the proposed filter becomes a five pole bandpass filter. A dumbbell shaped defected ground structure on either side of CPW MRS improves the return loss almost less than 20dB over the whole UWB passband. The simulated results of proposed filter show good transmission response within passband and good rejection in out of the band. The simulated and measured results are very close to each other which proves the efficacy of proposed design.

Formation of bimetallic dumbbell shaped particles with a hollow junction during galvanic replacement reaction.

The galvanic replacement reaction (GRR) has been shown to be an effective method to fine tune the structure of monometallic nanoparticles by controlling the precursor concentration and surface ligands. However, the structural evolution of nanoparticles is not well understood in multimetallic systems, where along with oxidation, dealloying and diffusion occur simultaneously. Here, we demonstrate that by controlling the rate of GRR in AuCu alloy nanorods, they can be transformed into either AuCu hollow rods or AuCu@Au core-shell spheroids. Interestingly, the transformation of rods into spheroids involved a critical intermediate state with a hollow junction and dumbbell shape. The formation of a hollow junction region was attributed to preferential diffusion of Cu atoms to the tips caused by the polycrystallinity and high curvature of the tips of the initial template. This structural transformation was also monitored in situ by single particle scattering spectroscopy. The coupling between the two ends of the dumbbell-shaped intermediate connected with a hollow metallic junction gives rise to additional plasmonic features compared with regular rods. Electrodynamic simulations showed that varying the dimensions of the hollow part by even one nanometer altered the plasmon resonance wavelength and lineshape drastically. This study shows that single particle plasmon resonance can be used as an exquisite tool to probe the internal structure of the nanoscale junctions.

Multifunctional Dumbbell-Shaped DNA-Templated Selective Formation of Fluorescent Silver Nanoclusters or Copper Nanoparticles for Sensitive Detection of Biomolecules.

In this work, a multifunctional template for selective formation of fluorescent silver nanoclusters (AgNCs) or copper nanoparticles (CuNPs) is put forward. This dumbbell-shaped (DS) DNA template is made up of two cytosine hairpin loops and an adenine-thymine-rich double-helical stem which is closed by the loops. The cytosine loops act as specific regions for the growth of AgNCs, and the double-helical stem serves as template for the CuNPs formation. By carefully investigating the sequence and length of DS DNA, we present the optimal design of the template. Benefiting from the smart design and facile synthesis, a simple, label-free, and ultrasensitive fluorescence strategy for adenosine triphosphate (ATP) detection is proposed. Through the systematic comparison, it is found that the strategy based on CuNPs formation is more sensitive for ATP assay than that based on AgNCs synthesis, and the detection limitation was found to be 81 pM. What's more, the CuNPs formation-based method is successfully applied in the detection of ATP in human serum as well as the determination of cellular ATP. In addition to small target molecule, the sensing strategy was also extended to the detection of biomacromolecule (DNA), which illustrates the generality of this biosensor.

Exploring new opening-up membrane vesicles of two holes by using the relaxation method

Due to the discovery and study of opening-up lipid vesicles, the theoretical analysis and numerical calculation have aroused increasing interests of researchers. In the previous study, Suezaki and Umeda gave the opening-up vesicles near the spherical vesicles, such as the dish and cup shapes with one hole, and the tube and funnel shapes with two holes. These shapes are found at relatively low values of reduced, relaxed area difference a0. However, what are the stable shapes for high values of a0 is not known. Kang et al. found solutions of opening up dumbbell shapes with one hole. Whether or not there exist dumbbell shapes with two holes, and the phase transformation behavior between them remains unknown. The purpose of this paper is to explore a new kind of two-hole dumbbell shaped lipid vesicles and phase transformations between this kind of vesicle and previously found vesicles. Based on the area-difference-elasticity model, this paper tries to explore new solutions of the Euler-Lagrange equations of the opening-up membrane vesicles which meet the boundary conditions by using the relaxation method. A new branch of solution of dumbbell shapes with two holes is found. The phase transformations of closed dumbbell shapes and opening-up dumbbell shapes with one hole and two holes are studied in detail. To explore whether these shapes could be found in experiments, the energy of the cup, tube, and funnel shaped vesicles are also compared with the opening-up dumbbell shapes. It is found that at high values of a0, all the cup, tube, and funnel shapes will transform into closed spherical vesicles. So the energy of new opening-up dumbbell vesicles can be compared to that of closed spherical vesicles and closed dumbbell vesicles. It is found that the dumbbell shapes with one hole and two holes all have stable regions, implying that it is possible for these open dumbbells to be observed. Since the distance in the functional space is too far between the open dumbbell shapes and spherical vesicles, experimental test is needed to verify whether the dumbbell shapes with two holes will evolve continuously to the closed dumbbell shapes or to the closed spherical vesicles. It has been noticed that for relatively small values of a0, two holes vesicles may exhibit symmetrical tube shapes and asymmetric funnel shapes between which the phase transformation is continuous, because the funnel solutions bifurcate from the tube solutions. In order to check whether there exist asymmetric opening-up dumbbell shapes with two holes and the similar bifurcation behavior, a thorough search is made in the parameter space. So far no asymmetric dumbbell shape with two holes is found.

Large Dumbbell Shaped Vesicovaginal Calculus Managed with Holmium Laser Cystolithotripsy Followed by Staged Repair of Vesicovaginal Fistula

Complicated Vesicovaginal Fistulae (VVF) is prevalent in developing countries following obstetric injury. We report a rare case of a large dumbbell shaped vesicovaginal calculus measuring 7x 4.6cm in a patient with recurrent, complicated VVF managed successfully in two stages 6 weeks apart. Holmium laser (30 Watt) cystolithotripsy was used to break the vesical portion of the stone at the waist of the dumbbell, followed by delivery of vaginal part of the stone. Trans-abdominal VVF repair (O'Connor method) with omental interposition flap with right side ureteric reimplant was done after six weeks. Our case was unique because of occurrence of a larger sized fistula after a gynaecological surgery. She had developed larger stone (weight more than190gm- vaginal component) into the fistula tract. Also she had undergone multiple failed VVF repair attempts before. Use of holmium laser energy to break the stone was unique which minimized the morbidity of the first procedure leading to early recovery followed by staged repair of fistula after six weeks.