Volume 7, Issue 2, February 2016

Biosensors And Bioelectronics Symposium (BBS - 2016), Sweden 

Ashutosh Tiwari

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 89-89
DOI: 10.5185/amlett.2016.2001

VBRI Press is pleased to announce ‘Biosensors and Bioelectronics Symposium' during 23 – 25 August 2016, Sweden. It is a three-day international event organised by International Association of Advanced Materials, Biosensors and Bioelectronics Centre - Linköping University on the Baltic Sea from Stockholm-Helsinki-Stockholm by the Viking Line Cruise M/S Mariella. The aim of symposium is to provide advances in biosensors and bioelectronics and related sectors such as telecommunications, mobile & digital health expert systems and distributed diagnostics and also provide the premier interdisciplinary symposium for researchers, engineers and educators to present and discuss the most recent trends and practical challenges encountered adopted in the field of Biosensors and Bioelectronics.

Properties Of Novel Bone Hemostat By Random Co-polymer Of Ethylene Oxide And Propylene Oxide With sugar-containing Hydroxyapatite

Eri Shima; Yoshiro Musha;Kiyoshi Itatani; Tomohiro Umeda

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 90-94
DOI: 10.5185/amlett.2016.6132

Novel hemostatic agents were prepared using (i) phosphoryl oligosaccharides of calcium (POs-Ca ® 45 and POs-Ca ® 50 with calcium contents being 4.5 and 5.0 mass %, respectively), (ii) sugar-containing hydroxyapatites (s-Ca10(PO4)6(OH)2; s-HAp) obtained by the hydrolyses of POs-Ca ® 45 and POs-Ca ® 50, respectively (s-HAp(45); Ca/P ratio = 1.56, 61.2 mass % HAp and 38.8 mass % organic materials and s-HAp(50); Ca/P ratio = 1.61, 79.3 mass % HAp and 20.7 mass % organic materials), and (iii) thermoplastic resin (random copolymer of ethylene oxide (EO) and propylene oxide (PO)) (EPO). The gels formed by mixing the EPO with water (EPO/water (mass ratio): 0.20) were freeze-dried at -50 ËšC for 15 h, and then blended with POs-Ca or s-HAp ((POs-Ca or s-HAp)/EPO-EO (mass ratio): 0.2). The noted findings due to the addition of POs-Ca or s-HAp to the composite gels were: (a) the stanching time of more than 80 min due to the addition of POs-Ca ® 50 to the composite gel with EPO : EO : water = 25 : 15 : 60 (mass ratio) (25EPO-15EO) and (b) formation of osteoid at the drilled hole within the tibia and femur of Japanese white rabbits due to the addition of s-HAp(45). The combined addition of POs-Ca and s-HAp to the EPO-EO were expected to enhance the hemostasis and bone regeneration. 

Using Titanium Dioxide/carbon Nanotubes To Remove Humic Acids In Water

Y. P. Tsai; J. C. Yang; P. C. Chuang; C. C. Chou; J. W. Lin

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 95-97
DOI: 10.5185/amlett.2016.6100

This study used multi-walled carbon nanotubes (MWCNTs), TiO2 and their mixture (TiO2/CNT) to remove humic acids (HA) in water. The thermodynamic parameters with respect to the adsorption of MWCNTs, including free energy of adsorption (ΔG 0 ), enthalpy (ΔH 0 ), and entropy (ΔS 0 ) changes, are further calculated in the study. The ΔH 0 data showed the adsorption of HA onto MWCNTs is an endothermic physisorption. The ΔG 0 data indicates the adsorption of HA onto MWCNTs was spontaneous and thermodynamically favorable. Photocatalytic experiments showed 60 mgl -1 of HAs were completely degraded and mineralized as CO2 after 5 h UV irradiation by 0.8 gl -1 of TiO2, indicating the efficiency of TiO2 for the removal of HA is better than CNTs. The experiments of TiO2/CNT indicated the photocatalytic efficiency of TiO2 in the presence of CNTs was not improved, even worse than TiO2 alone. However, the photocatalytic efficiency of TiO2/CNT mixture became better than TiO2 alone due to the supply of oxygen by aeration, ascribing to the reason that the provided oxygen might be adsorbed on the surface of CNTs and accept e- as well as form •O2 - , which also leads to the formation of •OH - in the system. 

Application Of Liquid Phase Plasma Process To The Synthesize Ruthenium Oxide/activated Carbon composite As Dielectric Material For Supercapacitor

Heon Lee; Sun-Jae Kim; Kay-Hyeok An; Jung-Sik Kim; Byung-Hoon Kim; Sang-Chul Jung

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 98-103
DOI: 10.5185/amlett.2016.6110

The ruthenium oxide/activated carbon composite (RCC) were synthesized using an innovative plasma-in-liquid process, which is known as liquid phase plasma (LPP) process. This technique uses a single-step process for the synthesis of metal nanoparticles on supporting materials. LPP process led to simultaneous precipitation of ruthenium and ruthenium oxide nanoparticles on the surface of activated carbon, which is then oxidized to ruthenium oxide during the thermal oxidation process. The specific capacitances of RCC electrodes prepared through the LPP and oxidation process were higher than that of bare AC. The specific capacitance increased with increasing LPP process duration and oxidation treatment. The specific capacitance of ruthenium oxide/carbon composite increased with increasing LPP process duration. The ruthenium oxide/carbon composite prepared through the LPP process and thermal oxidation showed smaller resistances and larger initial resistance slopes than bare activated carbon powder and this effect was intensified by increasing the LPP process duration. The RCC electrodes showed smaller resistances and larger initial resistance slopes than bare AC and this effect was intensified by increasing the LPP process duration and oxidation treatment.

Effect Of Different Concentrations Of Dopant Titanium Dioxide Nanoparticles On Electro-optic And dielectric Properties Of Ferroelectric Liquid Crystal Mixture

Pradeep Kumar; Avinash Kishore; Aloka Sinha

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 104-110
DOI: 10.5185/amlett.2016.6090

In the present study, the insulating titanium dioxide (TiO2) nanoparticles were dispersed in two different concentrations of      0.5 wt % and 1.0 wt % in pure ferroelectric liquid crystal (FLC) mixture, W206E. The effects of different concentrations of dopant TiO2 in W206E for electro-optical and dielectric properties have been studied. The optical microscopy measurements clearly show the isotropic transition temperature of both the doped samples slightly increases by about 1 ~ 2 0 C as compared to the pure sample. Further, with the increasing concentrations of dopant TiO2, the value of spontaneous polarization decreases. The value of dielectric permittivity also decreases for both the doped samples and this decrease in the value of permittivity is more prominent with increasing concentrations of TiO2 at the lower frequencies. The dielectric measurements also confirm the presence of Goldstone mode in Smectic C* phase in pure as well as in both the doped samples. The conductance measurements confirm the decrease in conductivity of doped samples as compared to the pure W206E FLC. This study may help in improving the transition temperature and reducing the impact of free ionic charge impurities on various physical properties of liquid crystal host by screening the free ions using TiO2 nanoparticles as dopant. 

Study Of Laser Beam Modulation Influence On Structure Of Materials Produced By Additive Manufacturing

Anna Okunkova; Sergey V. Fedorov;Andrey Gusarov; Marina Volosova; Pavel Peretyagin; Ivan Zhirnov; Pavel Podrabinnik

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 111-115
DOI: 10.5185/amlett.2016.6143

In the article, the study of laser beam modulation influence on the structure of materials produced by one of the methods of additive manufacturing as selective laser melting (SLM) is provided. For the purpose of creating a smoother temperature gradient and the optimal conditions of the heat and mass transfer in the melting pool, an experimental stand for SLM-processing with the system of laser beam power density distribution modulation was created. The laser beam modulation gives promising results for higher parameters’ combinations such as power more than 150W and scanning velocity more than 50 mm/sec. The single track’s formation was produced by different power density distribution as Gaussian, Flat-top and Inverse Gaussian (Donut). All the received single tracks were studied with the use of optical and SEM microscopy. The results produce important data about reducing the width of powder consolidation zone, more even structure and higher productivity. 

Ferromagnetism In Sol-gel Derived ZnO: Mn Nanocrystalline Thin Films

M.Tanemura and P. K. Shishodia; M.Tanemura;P. K. Shishodia

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 116-122
DOI: 10.5185/amlett.2016.5966

This paper reports the growth of Mn doped ZnO thin films by sol-gel technique with different Mn concentration (0-20 %). Structural and vibrational properties have been measured by X-ray diffraction and Raman spectroscopy. The films exhibit crystalline nature with (002) preferential orientation. The crystallite size and lattice parameters have been estimated as a function of Mn concentration. The Raman spectrum of the ZnO film shows the peaks corresponding to E2 (high) mode at 434 cm -1 assigned to Zn-O bond and A1 (LO) mode at 575 cm -1 . The elemental analysis of the films have been performed using X-ray photoelectron spectroscopy confirms the presence of Zn, O and Mn in doped films. Surface morphology and roughness of the films are observed by atomic force microscopy. The optical bandgap is found to decrease with Mn concentration as estimated by Tauc’s plots. Room temperature ferromagnetism has been obtained in ZnO: Mn thin films by superconducting quantum interference device. 

Impact Of Oxygen Diffusion On The Performance Of HfO2/GaAs Metal-oxide-semiconductor Field-effect-transistors

Anindita Das; Sanatan Chattopadhyay; Goutam Kumar Dalapati

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 123-129
DOI: 10.5185/amlett.2016.6277

In the current work, electrical performance of n-channel GaAs MOSFETs with HfO2 gate dielectrics has been investigated by considering the impact of oxygen diffusion from gate dielectric layer. Initially, the HfO2/GaAs MOS capacitors are fabricated and its relevant process recipe has been simulated. The key parameters are extracted from both the experimental and simulated results to calibrate the simulator. The extracted parameters are subsequently fed into the simulator to investigate electrical performance of n-channel GaAs MOSFETs with varying gate lengths. The elemental diffusion of oxygen at HfO2/GaAs interface has also been incorporated since oxygen naturally diffuses into the GaAs layer during deposition and annealing steps and thereby alters the effective doping concentration in the channel. The diffused oxygen has been observed to improve electrical performance parameters such as transconductance and threshold voltage, however, degrades DIBL of the HfO2/GaAs MOSFET devices.

Effect Of The Granulation Of Starting Powder On Superplastic Deformation Of Hydroxyapatite

Ryo Yamazaki; Yoshio Sakka;Kiyoshi Itatani; Koji Morita

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 130-135
DOI: 10.5185/amlett.2016.6135

The effect of the granulation of starting powder on the superplasticity of hydroxyapatite (Ca10(PO4)6(OH)2, HAp) specimen was examined; the tensile elongation of specimen at high temperature was measured in order to evaluate the superplastic deformation. The translucent ceramics were fabricated using HAp powders with and without granulate (HAp and g-HAp) through the pulse current pressure sintering at 1000 ºC for 10 min: the mean grain sizes in both cases were approximately 0.2 mm. The tensile elongation of g-HAp specimen at 1000 ºC was 289 % (strain rate: 1.2 × 10 -3 s -1 ). The tensile stress was always lower than 30 MPa with maximum stress of 28.3 MPa, in contrast to the case of HAp specimen showing the maximum stress of 75.3 MPa (tensile elongation: 344 %). The lower stress of g-HAp specimen, compared to the case of HAp specimen, indicated the weak bonding of grains, but the failure being occurred by the concentrated stress at the strong bonding sites.  

Relaxations In Gelatin Hydrogels Probed By Dynamic Light Scattering

Nitin Kumar; Vinay Kumar; Jitendra Sharma

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 136-143
DOI: 10.5185/amlett.2016.6012

The relaxation behavior of gelatin aqueous solutions has been investigated by time resolved dynamic light scattering (TRDLS) measurements at different temperatures spanning the entire sol to gel phase transition behavior of the system (i.e. from 5 min to 1440 min after a sudden quench from high temperature sol to low temperature gel state), when the chosen gelatin concentration in water was maintained at 5 % (w/v), well over the overlap threshold. The quantity of interest, structure factor S (q,τ), has been obtained from the experimentally measured autocorrelation function,  g2(τ), allowing appropriate heterodyne contribution. The nonlinear regression analysis of the obtained scattering profiles (variation of structure factor vs. delay time) exhibited good fits to the function S(q,τ) ~A exp(-Dq 2 τ) + B exp(-(τ/τc) β ), up tosystem evolution time of 360 min, whereas the data obtained after 360 min showed appropriate fits to S(q,τ) ~A exp(-Dq 2 τ)+ Cτ -α + B exp(-(τ/τc) β ). The temporal behavior of different fit parameters defining the transient structural network formed in the system has been quantified and analyzed under the purview of well-defined theories. Furthermore, the evolution of particle dynamics from fast to slow and then to almost frozen behavior has been explored through the continuous evaluation of ‘Gelation factor (κ)’ at different stages of system evolution times during the measurements.

Enzymatic Ring Opening Polymerization Of É›-caprolactone By Using A Novel Immobilized Biocatalyst

Nurefsan Gokalp; Cansu Ulker; Yuksel Avcibasi Guvenilir

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 144-149
DOI: 10.5185/amlett.2016.6059

In this study, an amorphous silica material was used as a carrier to immobilize Candida antarctica lipase B (CALB) by crosslinking method for ring opening polymerization of É›-caprolactone (É›-CL). The optimum temperature, enzyme concentration and time period were investigated for poly(É›-caprolactone) (PCL) synthesis via ring opening polymerization of É›-CL catalyzed by immobilized CALB (IMCALB). Molecular weights of PCLs were determined by using gel permeation chromatography (GPC) and hydrogen nuclear magnetic resonance ( 1 H-NMR) analysis. The surface morphologies of PCLs were analyzed by scanning electron microscopy (SEM). Besides, PCLs were successfully characterized by fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. The results showed that the immobilized lipase by crosslinking method via glutaraldehyde possessed good activity and stability. By using this immobilized enzyme, high molecular weights and monomer conversions of PCLs were achieved about 9000 g/mol and     90 %, respectively. This work has showed that activity of CALB increased about 17 % dramatically after immobilization process, and PCL was synthesized via enzymatic polymerization catalyzed this novel enzyme, which provides an effective method for conducting “green polymer chemistry”. 

Synthesis, Characterization And Electrochemical Studies On Novel Li2MZrO4 (M = Fe, Mn) Cathode Material For Lithium-ion Battery

Bikash Mandal; I. Basumallick; Susanta Ghosh

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 150-155
DOI: 10.5185/amlett.2016.6089

We report a novel cathode of the molecular formula, Li2MZrO4 (M = Fe, Mn), based on an inexpensive, earth-abundant, and eco-friendly materials, which have theoretical capacities within 119 – 238 mAh.g -1 depending on the number of lithium ions extracted from material, suitable for high power rechargeable lithium-ion battery. X-ray diffraction (XRD) revealed tetragonal crystal structure of the synthesized material. SEM images illustrate the formation of porous material with large surface area.  The cyclic voltammograms of Li2MZrO4 (M=Fe, Mn) showed only one pair of redox peak corresponding to the anodic and cathodic reactions within a potential window of 2.2 – 4.5 volts vs. Li/Li + . The first discharge capacities were 89 mAhg -1 for Li2FeZrO4, whereas in case of Li2MnZrO4 it was 94 mAhg -1 at 0.1 C rates, which are equivalent to removal of one lithium ion from the compounds.

Nanoreinforced Concrete: Effect Of Gamma-irradiated SiO2 Nanoparticles

Aldo G. P

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 156-162
DOI: 10.5185/amlett.2016.6145

The effect of gamma-irradiated SiO2 nanoparticles on microstructure and mechanical properties of concrete was studied. SiO2 nanoparticles were irradiated at different irradiation doses (10, 50, 100 and 150 kGy) and then analyzed by transmission electron microscopy, Fourier-transform infrared and Raman spectroscopies. Such ionizing treatment allowed improving the physical interactions between the nanoparticles and the cementitious matrix. Compressive strength and dynamical modulus of elasticity on concrete samples were determined. The results show significant improvements on these mechanical features when irradiated SiO2 nanoparticles were added; having up to 127 % of improvement for compressive strength and a 24 % for elasticity modulus when comparing to non-irradiated nanoparticles-reinforced concrete. Such improvements are related to the microstructural changes of concrete analyzed by Infrared spectroscopy and observed by scanning electron microscopy. Research shows important advances in the development and understanding of microstructure for nanoreinforced concrete with irradiated SiO2 nanoparticles.  

Synthesis, Physico-chemical Characteristics And Cellular Behavior Of Poly (lactic-co-glycolic Acid)/ Gelatin Nanofibrous Scaffolds For Engineering Soft Connective Tissues

Farnaz Ghorbani; Hanieh Nojehdehyan; Ali Zamanian; Mazaher Gholipourmalekabadi; Masoud Mozafari

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 163-169
DOI: 10.5185/amlett.2016.6003

There have been several attempts to synthesis biodegradable polymeric constructs with adequate porous structures for soft connective tissues. In this study, randomly-oriented PLGA-gelatin nanofibrous scaffolds were synthesized by electrospinning method. We offered an appropriate solvent (2, 2, 2-trifluoroethanol) to dissolve both polymers for achieving a homogenous solution without inducing any toxic effects. The results confirmed the formation of high porous and bead free scaffolds, in which an increase in the injection rate slightly decreased the mechanical, swelling ratio and biodegradation behaviors. The modulus and tensile strength for the scaffolds with the injection rate of 0.2 ml/hr were 0.72 ±0.02 and 2.70 ±0.33, respectively. In addition, the evaluation of cell proliferation demonstrated that L929 fibroblast cells spread well on the scaffolds, indicating that they are able to support cell attachment. A possible chemical bond formation has been also suggested for the blending mixture of PLGA and gelatin molecules.

Photoluminescence Studies Of Eu3+ Ions Doped Calcium Zinc Niobium Borotellurite Glasses

P. Rehana; O. Ravi; B. Ramesh; G.R. Dillip; C. Madhukar Reddy; S. W. Joo; B. Deva Prasad Raju

Advanced Materials Letters, 2016, Volume 7, Issue 2, Pages 170-174
DOI: 10.5185/amlett.2016.5870

A facile melt quenching technique was employed to prepare Eu 3+ -ions doped TRZNB glasses using commercial powders through mixing the specific weights of batches. The compositions prepared were 10TeO2 + 15RO + 5ZnO + 10Nb2O5 + 59B2O3 + Eu2O3 (where R= Mg, Ca and Sr). Under 395 nm excitation wavelength, p < /span>hotoluminescence (PL) and lifetime measurements of Eu 3+ -doped TRZNB glasses were recorded and reported. The PL spectra composed of five emission bands that are originating from the 5 D0 metastable state to 7 FJ (J = 0 - 4) lower lying states. Using the emission intensities of 5 D0→ 7 F2 and 5 D0→ 7 F4 transitions, respectively, the Judd–Ofelt (J–O) intensity parameters such as â„¦2 and Ω4 were calculated by considering the magnetic dipole (MD) 5 D0→ 7 F1 transition as reference. The radiative parameters such as spontaneous emission probabilities (AR), lifetimes (τm), branching ratios (βm) for different excited states were estimated theoretically. For all the glasses, the decay profiles were fitted to the single exponential equation. The obtained intense red emission at about 616 nm assigned to the 5 D0 → 7 F2 transition suggested the potentiality of present Eu 3+ -doped TRZNB glasses as a laser host.