bluuebunny/crossref_metadata_2025 huggingface dataset:
The Doping Effects of SiC and Carbon Nanotubes on the Manufacture of Superconducting Monofilament MgB2 Wires
Authors: Imaduddin Agung , Samsulludin Samsulludin , Wicaksono Muhammad Reza , Saefuloh Iman , Herbirowo Satrio , Yudanto Sigit Dwi , Hendrik Hendrik , Nugraha Heri , Lusiana Lusiana , Mabruri Efendi , Darsono Nono , Pramono Andika Widya
Published: August 2019

MgB2 superconductor is a superconductor with a critical temperature of around 39K and has the potential to replace Nb3Sn and NbTi as superconducting coils to produce high magnetic fields. In this study, monofilament wires have been made to analyze the doping effect of SiC and Carbon Nanotubes (CNT) in its manufacture using Powder-In-Tube (PIT) method. Stainless Steel (SS-316) tube was used as a tube filled with powders of starting materials of Mg, B, SiC and CNT. A total of 8 samples were prepared with variations in the addition of SiC, and CNT as much as 5, 10, and 15 wt %, and also the variations in the addition of Mg composition by 0 and 10 mol % from normal stoichiometric values. The samples were rolled and sintered at 800°C for 3 hours. The samples then were analyzed using SEM (Scanning Electron Microscopy) to analyze the surface morphology, XRD (X-Ray Diffractometer) to analyze the formed phases and crystal structures, and then resistivity versus temperature using cryogenic systems to analyze their superconductivity properties. Based on the results of the XRD analysis, the MgB2 phase is the major phase in the samples and the SiC doping causes the formation of minor phases of Mg2Si and Fe3C. The addition of SiC causes a decrease in crystalline properties of the MgB2 phase due to reaction with SiC, while the addition of CNT does not cause the formation of a new phase. Based on the results of the analysis of resistance versus temperature, it is seen that the addition of SiC causes a decrease in TC value. While the addition of CNT causes the improvement in the nature of superconductivity, but it also causes the decrease of its TC values.
Mechanical Exfoliation of Reduced Graphene Oxide From Old Coconut Shell as Radar Absorber in X-Band
Authors: Kurniawan Affandi Faisal , Anwar Mohammad Syaiful , Nadiyyah Khoirotun , Mashuri Mashuri , Triwikantoro Triwikantoro , Darminto Darminto
Published: August 2019

The purpose of this study is to determine the effect of heating temperature and the chemical exfoliation process on the reflection loss of r-GO synthesized from coconut shell. The heating process is carried out at temperature of 400°C and 700°C. The chemical exfoliation process is carried out by adding 1M H2SO4 solution in a ratio of 1: 1, 1: 5, and 1:10. Then, the process of washing is done using an ultrasonic cleaner. The XRD pattern indicates that coconut shell charcoal has formed the r-GO phase. In the chemical exfoliation process with the addition of 1M H2SO4 solution in a ratio of 1: 10 at a temperature of 400°C, it shows that the maximum reflection loss is -7.186 dB at 10.48 GHz with an electrical conductivity of 1.075 x 10-3 S/cm.
Enhanced Room-Temperature Ferromagnetism in Superconducting Pr2-xCexCuO4 Nanoparticles
Authors: Baqiya Malik Anjelh , Putra Putu Eka Dharma , Irfanita Resky , Suasmoro Suasmoro , Darminto Darminto , Kawamata Takayuki , Noji Takashi , Sato Hidetaka , Kato Masatsune , Koike Yoji
Published: August 2019

Recently, the so-called room-temperature ferromagnetism in any nanoparticles has been studied intensively. It is well known that the properties of ferromagnetism and superconductivity are contradictory in a superconducting high-Tc cuprate. The existence of ferromagnetism in the nanoparticles has been suggested to occur on the surface. This magnetism has been expected to come from defects inducing magnetic moments on oxygen vacancies at the surface of the nanoparticles. This work is to observe magnetism in nanosized superconducting Pr2-xCexCuO4 (PCCO) with x = 0.15 by means of a superconducting quantum interference device (SQUID). The magnetization curves of the reduced PCCO nanoparticles with the superconducting transition temperature, Tc, of ~25 K have revealed that there is weak ferromagnetism observed at room temperature. The magnitude of magnetization could be enhanced by oxygen reduction annealing in vacuum with increasing annealing temperature. A non-linear magnetization occurring in the reduced PCCO nanoparticles through the vacuum annealing process is probably due to a strong oxygen reduction producing more oxygen vacancies in the T'-structure.
Characterization of Barium M-Hexaferrite with Doping Zn and Mn for Microwaves Absorbent
Authors: Susilawati Susilawati , Doyan Aris , Taufik Muhammad , Wahyudi Wahyudi , Gunawan Eryn Ryantin , Fitriani Annisa , Nazarudin Nazarudin
Published: August 2019

The research was conducted to examine the content of Fe and other metal in natural sand of beach Ampenan, Mataram, Indonesia which is expected to be used as microwave absorbent material. Characterizations of the electrical and magnetic properties Barium M-Hexaferrite (BaM) with Zn-Mn doping (BaFe12-2xZnxMnxO19) are biosynthesized. Research carried out among others tested the metal content of Fe and other metals, synthesize BaFe12-2xZnxMnxO19. The samples were characterized using Vibrating Sample Magnetometer (VSM) and Network Vector Analyzer (VNA) for the test properties of electricity and magnetism, as well as the absorption of microwaves. The results from the AAS (Atomic Absorption Spectroscopy) testing showed that each gram of magnetic minerals in the natural sand containing 16.27 mg Fe, which states that the majority of metal components content is 69.80% Fe metal with the Magnetite and Hematite phases. The result from VSM showed that the coercivity value decreased when doping ion concentration and calcination temperature increased (0.16 Tesla at 600°C for x = 0.0 and 0.09 Tesla at 800°C for x = 1.0). Value of magnetic saturation and the magnetic remanence decreased with increasing ion concentration (Ms= 4.94 emu/g at x = 0.0 decreased to 0.31 emu/g at x = 1.0) and Mr = 3.43 emu/g for x = 0.0 decreased to 0.06 emu/g at x=1.0. These indicates that the sample has been soft magnetic. The result from VNA showed that the electrical conductivity values measured in the range 8.0-15.0 GHz indicate that the sample is a semiconductor (1.62×10-2 S/cm). The result from VNA showed that the microwave absorption properties increased at higher concentration of doping ions and the calcination temperature would increase the value of Reflection Loss (RL). Maximum RL value of the sample is -14.37 dB at 15 GHz and the absorption coefficient of 96.34%. These results indicate that the BaFe10.8Zn0.6Mn0.6O19 sample can be applied as a microwave absorbent material on X-band to Ku- band frequency. Keyword: Characterization, Barium M-Hexaferrite, doping, microwave, absorbent.
Comparative Study on Magnetism of Reduced Graphene Oxide (rGO) Prepared from Coconut Shells and the Commercial Product
Authors: Asih Retno , Yutomo Erik Bhekti , Ristiani Deril , Baqiya Malik Anjelh , Kawamata Takayuki , Kato Masatsune , Watanabe Isao , Koike Yoji , Darminto Darminto
Published: August 2019

Magnetism of reduced graphene oxide/rGO prepared by a green synthesis method from coconut shells (rGO-s) and the commercial product (rGO-c, ®Graphenea) have been investigated. Similar magnetic feature of a weak ferromagnetism concomitant with diamagnetic nature was observed in both samples. At 300 K, the saturation magnetization (MS) of rGO-s is approximately 14×10-3 emu/g, which is about 3 times of that observed in rGO-c (~5×10-3 emu/g). The noticeable difference in the MS is suggested due to the different concentration of oxygen-functional groups and other defects presented in the rGO sheets. The samples have similar structure and contains similar functional groups, yet rGO-s contains higher concentration of oxygen-functional groups and defects than rGO-c. A paramagnetic behavior was also indicated at low temperature. This study supports an indication of the defect-induced-magnetism in rGO and confirms that various magnetic features, such as ferromagnetic, diamagnetic and paramagnetic, can coexist in rGO.
Study of Magnetic Properties in Electron Doped Superconductor Eu2-xCexCuO4+α
Authors: Maryati Yati , Nafisah Nur'aini , Auliya Diba Grace , Nurwati Eka , Amalia Tiara , Tayubi Yuyu R. , Saragi Togar , Risdiana Risdiana
Published: August 2019

Electron-doped superconductors Eu2-xCexCuO4+α with x = 0.11, 0.13, 0.15, 0.17 and 0.19 have been synthesized using solid-state reaction method. The purpose of this research is to study the effect of covering treatment to its magnetic properties. The samples were covered by CuO to prevent the excess of oxygen in sample during heating process. All samples were characterized by susceptibility measurement to study the magnetic properties of Eu2-xCexCuO4+α. The trace of superconductivity was observed in the samples with x = 0.15 and 0.17.
Study of Magnetoresistance Effect and Magnetic Properties of La0.67Sr0.33Mn1-xNixO3 (x = 0 and 0.2) Material Prepared by Sol-Gel Method
Authors: Widyaiswari Utami , Kurniawan Budhy , Imaduddin Agung , Watanabe Isao
Published: August 2019

Mixed valence manganite materials have been studied due to their interesting physical properties such as their magnetoresistance (MR) effect. The change of Mn3+/Mn4+ ratio affects the possible bonds between anion and cation and their spin structure that may occur in the samples. The aim of this research is to study the change of magnetoresistance effect and magnetic properties of La0.67Sr0.33MnO3 (LSMO) by doping the Mn site with Ni ion. La0.67Sr0.33Mn1-xNixO3 samples were synthesized by using sol-gel method and characterized by using X-ray diffractometer (XRD) and Energy Dispersive X-ray spectroscopy (EDX) to confirm whether Ni has been doped successfully to the parental compound or not. XRD results showed that the samples have a single phase and Ni peak has been detected in the EDX result of Ni-doped LSMO. Resistivity and magnetic measurement showed that LSMO material has ferromagnetic metallic behavior, while x = 0.20 Ni-doped LSMO sample showed paramagnetic insulator behavior. The absolute value of the MR for un-doped sample is higher than the doped sample when the low field is applied, while under the influence of the high magnetic field, it become smaller than the doped sample.
Characteristics of Large Area Perovskite Solar Cells from Electrodes of Used Car Batteries
Authors: Bahtiar Ayi , Agustin Cyntia , Nurazizah Euis Siti , Aprilia Annisa , Hidayat Darmawan
Published: August 2019

Power conversion efficiency (PCE) of perovskite solar cells increases very rapidly and more than 22% is already achieved. However, some problems still need to be resolved for mass production and commercialization, including reducing production costs and development of large area solar cells. The best PCE is reached by very small active area, mostly below 0.5 cm2 which is mostly produced by spin-coating technique. Moreover, the perovskite precursor materials, mostly lead (II) iodide (PbI2) and hole-transport materials (HTM) Spiro-OMeTAD are expensive material in perovskite solar cells. Therefore, the use of low-cost perovskite precursors and low-cost HTM materials is one way to reduce the whole production costs of perovskite solar cells. Nowadays, many groups have been developed HTM-free perovskite solar cells using carbon-based mesoscopic solar cells for low cost production and large area perovskite solar cells, although the PCE of large area perovskite solar cells is still half than that very small area prepared by spin-coating technique. Here, we report our recent study to fabricate perovskite solar cells using mesoscopic carbon-based structure consisting of glass/ITO/TiO2/ZrO2/perovskite/carbon with active area larger than 1 cm2 by use of simple screen printing technique in ambient air with high humidity. We also synthesize PbI2 as perovskite precursor material from electrodes of used car battery to reduce the cost of solar cells production. Although, the PCE is still much lower than that reported by other groups, however, our study shows that perovskite solar cells from used car battery and with active area more than 1 cm2 can be fabricated in ambient air with high humidity by use of simple screen printing technique.
The Effect of Reduced Graphene Oxide (rGO) Coating on Electrical Conductivity of Lithium Ferro Phosphate (LFP) as an Alternative Cathode for Li-Ion Battery
Authors: Suarso Eka , Laila Anna Zakiyatul , Setyawan Firsta Agung , Zainuri Mochammad , Arifin Zaenal , Darminto Darminto
Published: August 2019

In this study an investigation has been conducted on the effect of reduced graphene oxide (rGO) coating on increasing the value of Lithium Ferro Phosphate (LFP) electrical conductivity. This coating process uses a variation of the mass ratio of LiFePO4/rGO by 90%:10%, 70%:20%, and 67%:33%. The LiFePO4 precursor was prepared using the sol-gel rute from the main commercial materials, namely Li2CO3 powder as a source of lithium ions, FeCl2.4H2O as a source of iron and NH4H2PO4 powder as a phosphate source. As for the coating used rGO extracted from coconut shell waste. The samples were calcined with temperature variations of 600°C, 650°C and 700°C in an argon environment for 10 hour. The phase purity and crystal structure of LiFePO4 were analyzed using XRD. The analysis of data from XRD was done using the the Match!, Rietica, and MAUD software. Based on the results of XRD analysis, LiFePO4 with high purity and good crystallinity was obtained when the sample was calcined at temperature of 700°C. The results of the MAUD analysis show that the best size of LiFePO4 crystal is 86,54 nm. LiFePO4/rGO nanocomposite was successfully synthesized by mechanical ultracentrifugation method. The characterization of the value of electrical conductivity, carried out using a four-point probe. The results show that the greater the percentage of rGO, the higher the value of electrical conductivity. The mass ratio of 67% LiFePO4 and 33% rGO shows an increment in good conductivity values, from the original order of 10-8 S/cm to the order of 10-4 S/cm.
Preparation of Lithium Iron Phosphate-Carbon Composite as a Cathode for Lithium Ion Battery
Authors: Rahayu Iman , Noviyanti Atiek Rostika , Rakhmawaty Diana , Anggraeni Anni , Bahti Husein Hernandi , Hidayat Sahrul , Risdiana Risdiana
Published: August 2019

Lithium iron phospate-carbon composite (LiFePO4/C) was successfully synthesized with various sintering temperature in order to find best synthesis condition resulting high quality of LiFePO4/C that can be applied for environmentally friendly of cathode in lithium ion battery. It is found that the specific capacity and the stability capacity of LiFePO4/C were improved to 17.6 mAh and 40.3% of capacity loss, respectively.
Energy Storage Characteristics of Electrochemically Deposited Graphene Oxide on ITO and Cu Substrates
Authors: Fitrilawati Fitrilawati , Marcelina Vika , Dzujah Diyan Unmu , Bahtiar Ayi , Hartati Yeni Wahyuni , Syakir Norman
Published: August 2019

Graphene Oxide (GO) is two dimensional material that has been widely studied as an electrode material for supercapasitor. We prepared thin films of GO on metal oxide substrate of indium tin oxide (ITO) and metal substrate of Copper (Cu) using electrochemical deposition technique from 0.5 mg/ml GO dispersed in water. ITO-GO film was prepared using voltage range of -1.6 V to 0 V (ITO) and Cu-GO film was prepared using voltage range of 0 V to 1 V at scan rate of 50 mV/s. Both samples were characterized using Cyclic Voltammetry (CV) measurements in 1 M KCl electrolyte at varied scan speed with platinum (Pt) as counter electrode and Ag/AgCl as reference electrode. We compare energy storage characteristics of ITO-GO and Cu-GO using cyclic voltammogram data. It is found that GO deposited in metal substrate of Cu has higer energy density compare to that deposited in metal oxide substrate of ITO.
Characteristics of CMC from Corncob and its Application as Electrode Binder in Lithium Ion Battery
Authors: Hidayat Sahrul , Mubarok Ibnu , Adiperdana Budi , Suroto Bambang Joko , Riveli Nowo , Hartati Yeni Wahyuni , Rahayu Iman
Published: August 2019

Corncobs are a waste product from corn farming that are abundant in Indonesia. Corncobs have a high cellulose content, more than 40%, which made it useful for synthesizing CMC. CMC is a cellulose derivative that is widely used in many industries such as food, pharmaceutical, detergent, textile, cosmetic product and binder. In this paper, we use CMC that are synthesized from corncobs as binder in the electrodes of lithium ion battery. The steps of synthesizing CMC from corncobs started with the isolation of the cellulose, then followed by the processes of alkalization, carboxymethylation and finally the purification. FTIR spectrum shows that CMC are successfully synthesized. The presence of strong absorption band at 1613 cm-1 is related to the stretching vibration of the carboxyl group (COO-). The absorption in the 1300–1450 cm-1 region is due to symmetrical deformations of CH2 groups. While the broad absorption around 3427 cm-1 is due to the stretching of the hydroxyl groups (-OH). Test on three samples of different sizes, (mesh-100, mesh-60 and mesh-40) gives CMC purity values of 98.69%, 98.56% and 97.77%, respectively. In the application of CMC as anode binder, the best composition is 4% CMC, where it gives the highest conductivity of 0.587 S/cm. Voltammogram measurement with a scan rate of 50 mV/s in the voltage range of -1 to 1 Volt gives the capacitance value of 2237 μF.
Effect of Ni Doping Variations on Microstructure and Conductivity of Cathode LiNixFe1-x PO4/C Materials
Authors: Zainuri Mochammad , Subagyo Bintoro Anang , Novialent Ega
Published: August 2019

The cathode material of LiNixFe1-x PO4 / C in this study was synthesized through a solid process, using Ni ion dopping variations concentration are x = 0.01, 0.02, and 0.03. Effect of dopping variations of Ni ions on cathode material characterized by microstructure and electrical properties using XRD, PSA, SEM and EIS. The results of the XRD analysis showed that LiFePO4, Li3Fe2PO4 and Fe2O3 phases were formed. Conductivity Test results showed that conductivity before dopping of LFP / C was 10.24x10-4 S / cm, and after dopping with Ni ion are x = 0.01; 0.02 and 0.03 have the respective electrical conductivities are LiNi0.01 Fe0.99 PO4 / C of 7.75 x10-4 S / cm, LiNi0.02 Fe0.98 PO4 / C of 10.334 x10-4 S / cm, and LiNi0.03 Fe0. 97 PO4 / C of 4.87 x10-4 S / cm. With the highest electrical conductivity value on the cathode LiNi0.02 Fe0.98 PO4 / C.
Effects of Spin-Orbit Coupling on the Electronic and Excitonic Structures of Monolayer WS2
Authors: Dharma Budi Eka , Syahroni Ahmad , Majidi Muhammad Aziz
Published: August 2019

Transition metal dichalcogenides (TMDs) display unique properties in their monolayer structures, namely a direct band-gap transition, which becomes a promising candidate for optoelectronics applications. Among them, WS2 exhibits strong spin-orbit interaction which splits the excitonic peaks as observed in the experimental data up to ~400 meV. Unlike the other TMDs, the first excitonic peak A is very sharp for WS2, while the secondary peak B is broader with smaller relative intensity. In this paper, we perform first-principles calculations on the electronic band structure and solve the Bethe-Salpeter equation for the complex dielectric function of monolayer WS2 to study the effects of spin-orbit coupling on its excitonic structures. To resolve the excitonic peaks, in particular the B peak, we implement the double-grid method. We discuss the effects of electron-hole interaction on the absorption spectrum by comparing it with that calculated at the independent-particle level.
Numerical Simulation on Effects of TCO Work Function on Performance of a-Si:H Solar Cells
Authors: Sholih Ahmad , Hamdani Dadan , Wicaksono Sigit Tri , Hidayat Mas Irfan P. , Cahyono Yoyok , Darminto Darminto
Published: August 2019

In this paper, we have investigated the effect of the work function of transparent conducting oxides (TCO) on the performance of a-Si:H p-i-n solar cells, including open circuit voltage (VOC), short circuit current (JSC), fill factor (FF) and conversion efficiency, using AFORS-HET software. The simulation has focused on two layers: front contact work function (ΦTCO-front) and back contact work function (ΦTCO-back) with various band from 4.7 eV to 5.3 eV and 4.2 eV to 4.9 eV respectively. From the simulation results, we know that the work function of TCO greatly affects the performance of solar cells such as Voc, Jsc, FF and conversion efficiency. By optimization, we arrive at results for Voc, Jsc, FF and conversion efficiencies of 0.88 V, 8.95 mA / cm2, 65% and 5.1% respectively. This result is obtained on ΦTCO-front 5.2 eV. When ΦTCO-front 5.2 eV, the value of VOC, FF and conversion efficiency has been saturated, while the value of the J sc actually begins to decrease. Furthermore, when the ΦTCO - back is 4.3 eV, we get the best results for VOC, Jsc, FF and conversion Efficiency of 0.9 V, 8.96 mA / cm2, 73 % and 5.9 % respectively. When ΦTCO-back 4.3 eV, the value of VOC, FF and conversion efficiency begins to decrease, while the value of the Jsc does’t change significantly. These optimizations may help in producing low cost high efficiency p-i-n solar cells experimentally.
A Potential Application of Photonic Jet in Observing Micro-Metric Materials
Authors: Abdurrochman Andri , Wahidullah Muhamad Octamar , Naufal Dziban , Sofiati Dewi Syarah , Aprilia Annisa , Safriani Lusi , Perrin Stéphane , Lecler Sylvain
Published: August 2019

Photonic jet microscopy is a technical field of microscopy applying photonic jet phenomenon to increase the resolution of objects or area of objects being observed. Mostly it is used in optical microscopy as the demand of visual observations are increased, especially for the micro-metric biological objects. In addition to our previous works inoptical assessment of observing a micrometric object under a microsphere using an optical microscope, now we made the electromagnetic assessment. It concludes if smaller microsphere magnifies greater than bigger microsphere. Therefore, applying photonic jet microscopy for visual observation is getting closer.
Preparation and Characterization of Electrospun Composite Fiber of Polymer-TiO2
Authors: Yudoyono Gatut , Sudarsono Sudarsono , Anggoro Diky
Published: August 2019

Nanocrystal TiO2 has been synthesized from TiCl3 as a precursor using the co-precipitation method. Synthesis parameters are chosen to produce the anatase phase of TiO2 nanomaterials. Polymer-TiO2 composite was made from a mixture of TiO2 nanomaterials and poly(vinyl alcohol) (PVA) and ethyl cellulose polymer materials. PVA solvents were used by water (H2O) while for ethyl cellulose used terpineol solvents. Composite fiber was made using electrospinning method with sedimentation parameters: between the syringe and Al foil collector applied the voltage at 10 kV, between the needle tip and the collector, the distance was 10 cm, the syringe pump was set at a constant flow rate of 1 ml/h, the collector rotation speed was 100 rpm , and humidity inside electrospinning machine was 40%. Samples were characterized using scanning electron microscopy (SEM) and x-ray diffraction (XRD). XRD results showed TiO2 crystal diffraction peaks when the composition of TiO2 was quite large, whereas for only a small TiO2 composition, the diffraction peaks did not appear and were only dominated by amorphous PVA. Deposition results showed that composite fibers have been formed for PVA polymers whereas fiber ethyl cellulose was not formed.
Structural Analysis and Electrical Properties of Amorphous Carbon Thin Films
Authors: Pamungkas Diajeng Indraswary , Mukarromah Mukarromah , Priyanto Budhi , Nakajima Hideki , Tunmee Sarayut , Darminto Darminto
Published: August 2019

The amorphous carbon (a-C) thin films have been developed by many researchers due to many superior properties. The aim of this research to study the structure of amorphous carbon thin film. Amorphous carbon was successfully prepared by carbonization of up to 200°C. Organic compounds that used in this research were coconut sap and its derivatives. The variation used in this research was a calcinating temperature ranging from 250°C, 400°C, and 600°C. Amorphous carbon powder was then mixed with aquades. Exfoliation process has been applied using an ultrasonic cleaner for 2 hours and then centrifuged at 4000 rpm for 30 minutes. Deposition technique used in this research was spin - coating. The X-ray diffraction pattern shows that the carbonization process produces amorphous carbon phase at diffraction angle of 2θ =15-30°. The infrared absorbtion in the region 500 to 4000 cm-1 was resolved into several peaks, which were assigned to C ̶ H, C ̶ O, C ̶ C, C=C and O ̶ H bonding. Photo Emission Spectroscopy (PES) was used to measure the percentage of sp2 and sp3 configuration in the sample. From the PES data, the percentage of sp2 configuration of coconut sap heated at 400°C is 55.32%. Four-point probe method was also used to measure the conductivity and band gap of each material, resulting in 2.67 – 8.33 S/m and 0.15 – 0.49 eV respectively.
Effect of Modified SiO2 on the Hydrophobic Properties as Self-Cleaning Materials
Authors: Silvia Linda , Wardani Aprilya Hartinah , Hapsari Yanurita Dwi , Zainuri Mochammad
Published: August 2019

In this work, hydrophobic of modified SiO2 coating for self cleaning material were prepared by dip-coating methods and solvothermal manual. SiO2 was successfully prepared from silica sand by purified followed sol-gel methods. Tetraetoxysilane (TEOS) and Hexamethyldisilanze (HMDS) were used as surface chemical modification agents with varied mass of SiO2, which were 1, 2, 3, and 4 g. X-ray fluorescence spectrometer (XRF) , X-ray powder diffraction (XRD), Particle size analyzer (PSA), Ultraviolet–visible spectrophotometer (UV-Vis), and Water contact angle (WCA) were employed to investigate the element composition, crystal structure, size of particles, transparency, and hydrophobicity of coating. The results indicated that modified SiO2 coatings has hydrophobic feature as self cleaning material (WCA > 90˚) for indium tin oxide (ITO) glass.
Particle Size Analysis of the Synthesised ZrO2 from Natural Zircon Sand with Variation of pH Deposition Using Alkali Fusion-Coprecipitation Method
Authors: Murti Cahyaning Fajar Kresna , Aldila Herman , Endarko Endarko , Triwikantoro Triwikantoro
Published: August 2019

Zirconia (ZrO2) is one of the refractory ceramic materials that have applications in several fields. The aim of this study was to synthesis ZrO2 from natural zircon sand collected from Kereng Pangi, Central Kalimantan with a variation of pH deposition using alkali fusion co-precipitation method. The synthesized ZrO2 began with the preparation process involved magnetic separation, milling, and leaching with HCl. Furthermore, the alkali fusion process was used KOH solution and heated in an electrical furnace at 700°C for 3 h whereas the co-precipitation process was carried out using a filtrate mixed with the NH4OH solution to reach a pH variation between 3–11 and then precipitated for 12 h. The precipitates were dried in an oven and then calcined at 800°C for 3 h. The structure of synthesized ZrO2 was characterized using XRD and the particle sizes were measured using particle size analyzer (PSA). The XRD analysis showed that the identified phase of zirconia powder is tetragonal with a crystal size in nanometer size. Result of PSA measurement revealed that the crystal size decreased in the range pH of 3 - 7, but increased in the range pH of 7 - 11. The biggest powder particle size could be achieved at 260 nm with pH 7 whereas the smallest size was at 143 nm occurred at pH 3.
Comparison between Lipofectamine RNAiMAX and GenMute transfection agents in two cellular models of human hepatoma
Authors: Berardo Clarissa , Siciliano Veronica , Di Pasqua Laura G. , Richelmi Plinio , Vairetti Mariapia , Ferrigno Andrea
Published: August 2019

RNA interference is a powerful approach to understand gene function both for therapeutic and experimental purposes. Since the lack of knowledge in the gene silencing of various hepatic cell lines, this work was aimed to compare two transfection agents, the liposome-based Lipofectamine™ RNAiMAX and the HepG2-specific, polymer-based GenMute™, in two cellular models of human hepatoma, HepG2 and Huh7.5. In the first part, we assessed transfection efficiency of a fluorescent Cy3-labeled negative control siRNA by cell imaging analysis; we found that cells treated with GenMute present a higher uptake of the fluorescent negative control siRNA when compared to Lipofectamine RNAiMAX-transfected cells, both in HepG2 and in Huh7.5 cells. In the second part, we evaluated GAPDH silencing with the two transfection reagents by RT-PCR similar GAPDH mRNA expression after each transfection treatment. Finally, we measured cell viability by the MTT assay, observing that cells transfected with GenMute have higher viability with respect to Lipofectamine RNAiMAX-administered cells. These results suggest that GenMute reagent might be considered the most suitable transfection agent for hepatic gene silencing.
Basal Hormones and Biochemical Markers as Predictors of Overtraining Syndrome in Male Athletes: The EROS-BASAL Study
Authors: Cadegiani Flavio A. , Kater Claudio E.
Published: August 2019

Context

Overtraining syndrome (OTS) and related conditions cause decreased training performance and fatigue through an imbalance among training volume, nutrition, and recovery time. No definitive biochemical markers of OTS currently exist.

Objective

To compare muscular, hormonal, and inflammatory parameters among OTS-affected athletes, healthy athletes, and sedentary controls.

Design

Cross-sectional study.

Setting

Laboratory.

Patients or Other Participants

Fifty-one men aged 18 to 50 years (14 OTS-affected athletes [OTS group], 25 healthy athletes [ATL group], and 12 healthy sedentary participants [NCS group]), with a body mass index of 20 to 30.0 kg/m2 (sedentary) or 20 to 33.0 kg/m2 (athletes), recruited through social media. All 39 athletes performed both endurance and resistance sports.

Main Outcome Measure(s)

We measured total testosterone, estradiol, insulin-like growth factor 1, thyroid-stimulating hormone, free thyronine, total and fractioned catecholamines and metanephrines, lactate, ferritin, creatinine, creatine kinase, erythrocyte sedimentation rate, C-reactive protein, lipid profile, hemogram, and testosterone : estradiol, testosterone : cortisol, neutrophil : lymphocyte, platelet: lymphocyte, and catecholamine : metanephrine ratios. Each parameter was statistically analyzed through 3-group comparisons, and whenever P < .05, pairwise comparisons were performed (OTS × ATL, OTS × NCS, and ATL × NCS).

Results

Neutrophils and testosterone were lower in the OTS group than in the ATL group but similar between the OTS and NCS groups. Creatine kinase, lactate, estradiol, total catecholamines, and dopamine were higher in the OTS group than in the ATL and NCS groups, whereas the testosterone : estradiol ratio was lower, even after adjusting for all variables. Lymphocytes were lower in the ATL group than in the OTS and NCS groups. The ATL and OTS groups trained with the same intensity, frequency, and types of exercise.

Conclusions

At least in males, OTS was typified by increased estradiol, decreased testosterone, overreaction of muscle tissue to physical exertion, and immune system changes, with deconditioning effects of the adaptive changes observed in healthy athletes.
Athletic Trainers' Practice Patterns Regarding Medical Documentation
Authors: Eberman Lindsey E. , Neil Elizabeth R. , Nottingham Sara L. , Kasamatsu Tricia M. , Bacon Cailee E. Welch
Published: August 2019

Context

Medical documentation is a required component of patient care in all health care professions.

Objective

To evaluate athletic trainers' perceived behaviors toward, barriers to, and confidence in their medical documentation.

Design

Cross-sectional study.

Setting

Web-based survey.

Patients or Other Participants

We purchased a list of randomly selected e-mails from the National Athletic Trainers' Association. Of the 9578 participants, 1150 accessed our questionnaire (12.0% access rate), 1053 completed at least 1 portion, and 904 completed the questionnaire in its entirety (85.8% completion rate). Of the participants, 60.1% (n = 569/947) were female, 66.6% (n = 632/949) held a master's degree, 39.3% (n = 414/1053) worked in a collegiate or university setting, and 36.1% (n = 381/1053) worked in a secondary school setting.

Main Outcome Measure(s)

We used a 31-item questionnaire with demographics (12 items), medical documentation behaviors (16 items), barriers (2 items), and perceptions (1 multipart item) sections. The questionnaire explored athletic trainers' behaviors as well as confidence in, comfort with, and concerns about their documentation practices (Cronbach α = 0.887). We used descriptive statistics to identify characteristics of central tendency (mean, standard deviation, mode, frequency).

Results

Participants always (45.7%, n = 478/1046) or very frequently (39.0%, n = 408/1046) used a double documentation system consisting of electronic and paper records (50.4%, n = 523/1038). They most often documented to provide legal protection (86.8%, n = 914/1053), because it is a legal obligation (79.1%, n = 833/1053), or to track patient progress (83.9%, n = 883/1053). The most frequently cited barriers to medical documentation were time (76.5%, n = 806/1053), managing too many patients (51.9%, n = 547/1053), technological concerns (17.2%, n = 181/1053), and software limitations (17.2%, n = 181/1053). Respondents believed they were competent, comfortable, and confident in their documentation practices.

Conclusions

We were able to evaluate the generalizability of previous research while adding to the understanding of the behaviors toward, barriers to, and perceptions about medical documentation. We confirmed that time and patient load affected the ability to perform high-quality medical documentation.
Identifying Meaningful Patient Outcomes After Lower Extremity Injury, Part 1: Patient Experiences During Recovery
Authors: Majewski-Schrage Tricia , Evans Todd A. , Snyder Kelli R.
Published: August 2019

Context

Determining meaningful aspects of health is crucial for outcome assessment; however, limited literature exists on the aspects of health that are deemed meaningful by the athletic patient population.

Objective

To identify experiences and meaningful outcomes after lower extremity (LE) musculoskeletal injury among collegiate athletes.

Design

Qualitative study.

Setting

University laboratory

Patients or Other Participants

A purposive sample of 20 athletes (10 men, 10 women; age = 20.1 ± 1.83 years) from a National Collegiate Athletic Association Division I institution in the Midwest who had sustained an LE injury.

Data Collection and Analysis

Semistructured face-to-face interviews and inductive data analysis were conducted. Trustworthiness of the data was established using member checks and peer debriefing.

Results

Four themes emerged from the data, revealing that physical changes, psychological changes, personal and lifestyle changes, and support were the most meaningful outcomes among athletes with an LE injury. The 4 themes were associated with 21 subthemes, indicating the complexity with which LE injury affects individuals

Conclusions

Our findings demonstrate the importance of caring for the whole person. Athletic trainers must broaden their focus to provide the best patient care and consider the person's activities and life demands outside of athletic participation. The themes identified in this study provide a basis for selecting appropriate health markers and outcome measures.
Altered Strength Profile in Achilles Tendinopathy: A Systematic Review and Meta-Analysis
Authors: McAuliffe Seán , Tabuena Ariane , McCreesh Karen , O'Keeffe Mary , Hurley John , Comyns Tom , Purtill Helen , O'Neill Seth , O'Sullivan Kieran
Published: August 2019

Background

Persistent strength deficits secondary to Achilles tendinopathy (AT) have been postulated to account for difficulty engaging in tendon-loading movements, such as running and jumping, and may contribute to the increased risk of recurrence. To date, little consensus exists on the presence of strength deficits in AT. Consequently, researchers are uncertain about the appropriate methods of assessment that may inform rehabilitation in clinical practice.

Objective

To evaluate and synthesize the literature investigating plantar-flexion (PF) strength in individuals with AT.

Study Selection

Two independent reviewers searched 9 electronic databases using an agreed-upon set of key words.

Data Extraction

Data were extracted from studies comparing strength measures (maximal, reactive, and explosive strength) between individuals with AT and healthy control participants or between the injured and uninjured sides of people with AT. The Critical Appraisal Skills Programme Case-Control Study Checklist was used to assess the risk of bias for the included studies.

Data Synthesis

A total of 19 studies were eligible. Pooled meta-analyses for isokinetic dynamometry demonstrated reductions in maximal strength (concentric PF peak torque [PT] slow [Hedges g = 0.52, 44% deficit], concentric PF PT fast [Hedges g = 0.61, 38% deficit], and eccentric PF PT slow [Hedges g = 0.26, 18% deficit]). Reactive strength, particularly during hopping, was also reduced (Hedges g range = 0.32–2.61, 16%–35% deficit). For explosive strength, reductions in the rate of force development (Hedges g range = 0.31–1.73, 10%–21% deficit) were observed, whereas the findings for ground reaction force varied but were not consistently altered.

Conclusions

Individuals with AT demonstrated strength deficits compared with the uninjured side or with asymptomatic control participants. Deficits were reported across the strength spectrum for maximal, reactive, and explosive strength. Clinicians and researchers may need to adapt their assessment of Achilles tendon function, which may ultimately help to optimize rehabilitation outcomes.
The Aristotelian mode of thought underlying research and theorizing in the field of stuttering
Authors: Goodgoll Michael L.
Published: August 2019

As a direct result of the prevalence of Aristotelian thinking in the field of speech pathology, research and theorizing has tended to ignore the individual, his unique characteristics and differences, and to concentrate on what is common between individuals. The therapist is therefore faced with being unable to utilize effectively any particular theory, since none of them explains the unique attributes of the individual case with which he has to deal. A non-Aristotelian approach to research on stuttering seems to hold more promise of attaining an eventual understanding of the individual stutterer.
Some misconceptions about infantile autism
Authors: Pletz E. B.
Published: August 2019

Recent studies throw light on certain widespread misconceptions about infantile autism and offer rational alteratives:(a) Autism should not be considered a disturbance in affective contact but a cognitive and perceptual difficulty. This difficulty, rather than social withdrawal, is the central feature of the disorder. Linguistic and problem solving studies tend to confirm this probability.(b) Pre-occupation with hand flapping and spinning objects in autistic children does not require interpretation, as recent neurological studies indicate the strong probability of a neurological basis for this tendency.(c) A highly permissive approach is not likely to help the autistic child and may intensify atavistic behaviours. To hold parents of autistic children culpable is unjustified. Progress in therapy and in the home is probably related to a systematic use of reinforcement.(d) The absence of speech by the age of five years no longer means a hopeless prognosis, as operant conditioning allows speech to be learned after this age. Dealing with autism as a cognitive dysfunction, Rimland23 emphasises the child's inability to comprehend his environment and to integrate his sensations, while Rutter29 shows the similarity between autism and receptive aphasia. He claims that social withdrawal is secondary to language difficulties in autism. For this reason and because the autistic child seems unable to learn under ordinary circumstances, it seems that reinforcement therapy practised within the framework of speech therapy would show the best results. Operant conditioning has been unjustly attacked on many accounts, but the hopeful prognosis and breadth of applicability it offers should be a spur towards dissipation of these misconceptions.
The investigation of the disintegration of phonemic discrimination on a perception and production level in adults with aphasia
Authors: Levinsohn J.
Published: August 2019

As more stress is being placed on the auditory disability of aphasics, the validity of dividing aphasic symptoms into expressive and receptive disorders is queried. The reflex-arc seems too simple a configuration to explain the complex functioning and breakdown of language. It is postulated that the auditory disorder is basic to aphasic symptoms on the level of understanding as well as that of production of language. Thus, if an aphasic patient shows a breakdown in the perception of phonemes, it seems likely that the auditory imperception will affect the production of the same phonemes. Aphasic subjects were presented with tests of phonemic discrimination on a perceptual and a production level and the similarity of phonemic errors was noted. The results of the experiment seemed to indicate that^a' hearing loss did not account for the subject's phonemic disintegration. However, it was not possible to control certain factors thus this result is not conclusive. The similarity between errors on an input level and those on an output level was poor, according to the result of the perception and production tests used in the study. However, despite the inadequacies of the tests used, all subjects showed'some degree of similarity and this tends to support the hypothesis. The errors in phonemic discrimination indicated by both perception and production tests were not random and inconsistent, but followed a trend. It was noted that the severity of the aphasic symptoms seemed closely linked with the degree of phonemic breakdown. Also, the subjects tested showed a significant similarity between auditory-type aphasic symptoms and phonemic discriminatory symptoms. Little similarity existed between phonemic errors in isolation and in spontaneous speech.
'n Ondersoek na sekere biolinguistiese verskynsels by hakkel
Authors: Uys I. C.
Published: August 2019

Verskeie navorsingsprojekte het al gepoog om die voorkoms van hakkel in verskillende kulture vas te stel, sonder om 'n verklaring van die voorkoms en aard van hakkelgedrag deur middel van 'n biolinguistiese benadering aan te bied. Linguisties-fonetiese faktore, soos vokale aanvangsmetodes, dui op 'n verskil tussen Afrikaans en Engels. Die harde aanset van aanvangsvokale in Afrikaans blyk 'n oorsaak te wees van 'n verhoogde voorkoms van hakkel op aanvangsvokale. 'n Biologiese proses (laringeale spanning, glottale afsluiting en verhoogde subglottale lugdruk) aan die een kant en 'n linguistiese verskynsel (die spesifieke eienskappe van foneem-realisering in verskillende tale) aan die ander kant, veroorsaak klaarblyklik die patologiese reaksie (laringeale hakkel).
'n Kommunikatiefgefundeerde ondersoek na bepaalde waarnemingsverskynsels by disfemie
Authors: Hugo René
Published: August 2019

Hierdie studieprojek stel hom ten doel die bestudering van bepaalde ouditiewe waarnemingsvermoëns by disfemie, soos gesien vanuit 'n kommumkatiewe oogpunt. Eksperiment 1: stel hom ten doel die bepaling van suiwertoonsensitiwiteit en spraakdiskriminasievermoëns van 'n groep van 10 hakkelaars, en die vergelyking van hierdie gegewens met 'n kontrole groep nie-hakkelaars. Die resultaat dui op 'n betekenisvolle verskil, tussen die suiwertoondrempelwaardes van die regterore van die hakkelaars en nie-hakkelaars en kan moontlik in verband gebring word met sowel terugvoeringsafwykings as gehoordominansieteorieë.Eksperiment 2: beoog die bepaling van waarnemingsdrempels van neutrale en negatiewe woorde (woorde waarop gewoonlik gehakkel word) by 'n groep hakkelaars, en die vergelyking hiervan met 'n aantal nie-hakkelaars. Die resultate toon 'n betekenisvolle verskil tussen hierdie 2 lyste vir die hakkelaars, maar nie vir die vlotsprekers nie. Ter verklaring kan aangevoer word dat die hakkelaars, op grond van emosionele kwaliteite verbonde aan die negatiewe woorde, hierdie woorde makliker waarneem as die vlotspreker, waarskynlik deur gebruik te maak van perseptuele verdedigingsmeganismes soos perseptuele ingestemdheid. Eksperiment 3: is gerig op die bepaling van die bestaan van onwaarneembaarheid van betekenisvolle stimuli by die hakkelaar tydens die hakkelpenode. Geen sodanige verskynsel kan betekenisvol aangetoon word nie, hoewel daar in die bespreking daarop gewys is dat 'n verandering in die eksperimentele prosedures nogtans so 'n fenomeen kan uitwys. In sy geheel gesien, is daar dus in hierdie studieprojek bepaalde waarnemings- abnormaliteite by die disfemie aangetoon wat nie by die vlotspreker gevind kan word nie. Hierdie abnormaliteite dui essensieel op 'n wyer siening van disfemie nl., as 'n komplekse, kommunikatiewe probleem.
Oncologic imaging in 2002 and beyond
Authors: Hricak Hedvig
Published: August 2019

No abstract available.
Modern trends in GI-oncology imaging
Authors: Margulis Alexander R.
Published: August 2019

No abstract available.
Imaging in oncology: From unknown primary to therapy response assessment
Authors: Schwartz Lawrence H.
Published: August 2019

No abstract available.
Management of a solitary pulmonary nodule
Authors: Greniér Philippe
Published: August 2019

No abstract available.
Lung cancer: What the surgeon needs to know
Authors: Payne Martyn , Linegar Anthony G.
Published: August 2019

No abstract available.
Editorial
Authors: Duncan Ian C.
Published: August 2019

No abstract available.
Renovascular anatomy as depicted by multislice helical CT
Authors: Hack Jonathan P.
Published: August 2019

No abstract available.
Questioning standard imaging protocols
Authors: Scher A. T.
Published: August 2019

No abstract available.
Navicular stress fracture
Authors: De Villiers R. V.P.
Published: August 2019

The diagnosis of a navicular fracture is difficult and often delayed due to a nonspecific clinical presentation and subtle imaging findings. Initial radiographs are often negative. Historically isotope bone scans were recommended, but now CT and MR imaging are suggested due to the higher specificity. Imaging of both feet allows internal comparison and may also detect an asymptomatic or unsuspected contralateral fracture. CT is a reliable indicator of fracture healing. The imaging evidence of fracture healing usually lags behind the clinical picture.
Microvascular revascularization for recurrent A1 anterior cerebral artery aneurysm postendovascular treatment: A case report and review of the literature
Authors: Musara Aaron , Yamada Yasuhiro , Takizawa Katsumi , Haraguchi Kenichi , Kawase Tsukasa , Tanaka Riki , Miyatani Kyosuke , Teranishi Takao , Mohan Krishna , Kato Yoko
Published: August 2019

The recurrence of aneurysms postcoil embolization is a common occurrence. Endovascular coiling has been noted to be more effective for small lesions rather than the giant aneurysms. A postembolization recurrent aneurysm is a difficult condition to manage. We present a case of a recurrent giant aneurysm of the anterior cerebral arteries (ACAs) first segment (A1). It was managed by superficial temporal artery to A3 segment of anterior cerebral artery bypass anastomotic revascularization plus distal A1- segment clipping. A literature review is presented for the management of giant A1 artery aneurysms.