Friedrich Schiller University in Jena, Germany, Germany
Ms. Sowmya K B
R V College of Engineering, Bengaluru, India, India
Edla Maria Bezerra Lima
Federal University of Rio de Janeiro, Brazil
Henrique José da Silva
UNIFRAN - University of Franca, Brazil
University of Arkansas for Medical Sciences (UAMS), Little Rock, Arkansas, USA, Nepal
Marcelo Machado Viana
Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
University of Nebraska-Lincoln, United States
Center for Physical Sciences and Technology, Lithuania
Zhou Bing Chen
The Hong Kong Polytechnic University, China
Israel Institute of Technology, Israel
Dr. Madhumita Mukhopadhyay
Amity University, India
Ana Paula Domínguez Rubio
University of Buenos Aires, Argentina
National Institute for Materials Science, Japan
Katholieke Universiteit Leuven, Belgium
The University of Hong Kong, China
Marcello Rubens Barsi Andreeta
Federal University of São Carlos, Brazil
Institute Polytechnqiue Paris, France
California State University of Northridge, United States
Ana M.O. Azevedo Universidade do Porto, Portugal
Protein discrimination using erythrosin B-based GUMBOS
In the past years, sensors have attracted increased attention as a facile and cost-effective approach for protein detection and discrimination. Different scaffolds have been employed for construction of sensors, including polymers, substituted porphyrins, and oligopeptide-functionalized resins 1. GUMBOS (Group of Uniform Materials Based on Organic Salts) have emerged as a promising class of materials for accurate identification of protein analytes. These compounds share similar features to those of ionic liquids, but have wide applicability potential due to their melting point range (25-250 ºC) 2. In this context, the usefulness of four novel erythrosin B (EB)-based GUMBOS as recognition elements for proteins with distinct molecular weights and isoelectric points was assessed. GUMBOS were synthesized using a simple metathesis reaction between the anionic dye (EB) and several phosphonium and ammonium cations. The effect of pH and incubation time on the discriminatory power was studied, being the assays performed in aqueous media at pH 3.0, 4.5, and 6.0 for 5, 10, and 15 minutes. Upon exposure to proteins, each sensor generated distinct absorbance response patterns that were analyzed using partial least squares discriminant analysis (PLSDA). The proposed sensing approach offers an interesting alternative to conventional analytical methods since it is simple (label-free) and rapid (only five minutes of equilibration time are required). Moreover, at pH = 6.0, EB-based GUMBOS allowed discrimination of five serum and non-serum proteins with 100% accuracy. The ability of GUMBOS to detect and discriminate between four distinct protein mixtures containing albumin and myoglobin was also studied. These binary mixtures were distinguished from each other with nearly 90% accuracy.
Igor Tkachenko Professor of Material Science Dep, Ukraine
Anomalies of room temperature tensile behavior of industrial low alloy steels in result of a volume heat treatment
Obtaining as high levels as possible for all the mechanical characteristics of modern structural steels has been remaining an actual task of Material Science and Engineering for decades. A possibility was recently shown for variety of industrial steels, grey and white irons to obtain after the “regenerative” heat treatment super-homogeneous and refined microstructures together with unusually high impact strength.
Dechao Geng Tianjin University, China
Liquid Cu catalyzed growth of single crystal 2D materials
Controlled growth of large-area and high-quality 2D materials has attracted intensive efforts in the past few decades owing to extraordinary properties and wide applications. Numerous methods have been developed for such aim, of which chemical vapor deposition (CVD) method offers compelling benefits in shaping 2D material single crystals due to its high controllability, high scalability and ultra-low cost. In my talk, liquid Cu assisted CVD method will be highly emphasized in formation of 2D crystals. Comparing to conventional solid Cu catalyst, the as-developed liquid Cu displayed several advantages over nucleation and growth of 2D materials. With introduction of liquid Cu, we first fabricated large-scale and uniform graphene single crystals and monolayer films, which showing relatively high carrier mobility. Inspired by this thought, novel 2D materials have also been successfully produced, such as Mo2C, hBN and SiC and so on. The controllable realization of a wide range of 2D materials on liquid Cu further demonstrates the generality in making 2D crystals. With those 2D materials as building blocks, a series of 2D heterostructures have been constructed on liquid Cu surface, such as graphene/hBN lateral heterostructure and graphene/Mo2C vertical heterostructure. In one word, with the help of liquid Cu catalysts, controllable growth of 2D single crystals has been realized by CVD approach.
Jagadish Chandra Mahato Assistant Professor of Physics Dep., India
Self-organized endotaxial cobalt disilicides nanowires on Si(110) surfaces: Fabrication and aspect ratio tunning of the nanowires
Self-organized growth of well-ordered endotaxial silicide nanowires (NWs) on clean Si(110) surfaces has been investigated by in-situ scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Co deposition on clean Si(110) reconstructed surfaces at ~ 600°C produces unidirectional CoSi2 NWs by reaction of cobalt with the hot silicon substrate. STM investigations reveal four types of distinct NWs, all growing along [1-10] in-plane direction except one type growing along in-plane  direction. There are also some nanodots. The cross-sectional TEM measurements show that the unidirectional NWs are of two types, namely flat-top and ridged. The NWs grow not only on the substrate but also into the substrate. CoSi2 in flat top NWs are in the same crystallographic orientation as the substrate Si and the buried interfaces between CoSi2 and Si are A-type. In the ridged NWs CoSi2 and Si are in different crystallographic orientations and the interfaces are B-type. The ridged NWs are in general wider and grow deeper into the substrate.1
The influence of post deposition annealing on the aspect ratio of these self-organized cobalt silicide nanowireson clean Si(110) surfaces has also been investigated by in situ scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) as well as by scanning electron microscopy (SEM). Half a monolayer of cobalt was deposited on the Si(110) surfaces at ∼600°C substrate temperature. Following cobalt deposition, the substrates have been annealed for different durations. Cobalt forms aligned cobalt disilicide nanowires upon reaction with the silicon substrate, following the twofold substrate symmetry. With increasing duration of annealing, the NWs have been found to grow with larger aspect ratio (length/width), eventually producing narrower NWs. These self-organized unidirectional NWs of sub-hundred nanometer width and ∼4–7 nm height produce a Schottky barrier with the silicon substrate and are expected to find applications in nano electronic devices.
Prof. Anatoliy Zavdoveev National Academy of Sciences of Ukraine, Ukraine
The effect of technological operations temperature on the mechanical properties and structure of high-strength steels grade S460M and S355J2
The use of high-strength steels with a yield strength in the range 350-460 MPa allows reducing the metal consumption of structures made for various purposes. These steels are used in bridge construction and other constructions in general, in the manufacture of oil & gas offshore platforms, supports of wind generators, ships, high pressure vessels, as well as in the manufacture of steel rail freight. Considering that the new generation of steels is obtained due to the integrated use of both microalloying and thermo-mechanical control process (TMCP), the properties obtained can be lost as a result of softening during the thermal treatment of steel. The purpose of the present work is to study the effect of high-temperature isothermal heating on the mechanical properties and structure of rolled sheets and simulated heat affected zone metal of micro-alloyed S355J2 and S460M steels obtained using normalization and thermomechanical treatment, respectively. It is shown that at a temperature T≤630 C, characteristic for treatment associated with the welding stress relieving, the mechanical properties of the investigated steels are stable within the limits of error. S460M steel, obtained by TMCP, can be used in the manufacture of welded steel structures that do not require hot straightening and stamping operations. Heating is allowed not higher than Ac1 (714 С), for relieving welding stresses. Steel S355J2 obtained through normalizing may be used in the manufacture of welded steel involving the operation of a temperature of up to 950 C.
Falk Eilenberger Friedrich Schiller University in Jena, Germany, Germany
Scalable Functionalization of Exposed-Core Fibers with CVD-Grown Monolayer Transition Metal Dichalcogenides
Monolayer transition-metal dichalcogenides  (TMDs) are a new and highly interesting material for optics and photonics due to their rich photophysics, their strong interaction with light, and large optical nonlinearities . However, their application is limited by the sub-nanometer interaction length, imposed by their atomic thickness; the enhancement of which is essential for future applications.
Recently, we have demonstrated a novel type of scalable functionalization technique for exposed-cored optical fibers (ECF) , where MoS2 and WS2 crystals are directly grown on the fiber’s core, based on a one-pot chemical vapour deposition CVD-growth process. We show that by adjusting the growing condition, the density of TMDs monolayers can be tuned.
The TMDs interact with the guided light by the evanescent field of the ECF’s guided mode, leading to the exciton formation, photoluminescence (PL) emission, and enhanced nonlinear interaction. The incident light was launched into one facet of the fiber and the PL or nonlinearity generated light was collected from the other face. It exhibits exciton peaks at 678 nm and 622 nm for MoS2 and WS2, as well as enhanced third harmonic generation. Other forms of enhanced nonlinear effects will be discussed in the presentation, as well. We expect that our work may lead to tunable light sources and fiber-based sensors.
Ms. Sowmya K B R V College of Engineering, Bengaluru, India, India
Designing and Building Verification Environment of I2C Controller
The Inter-Integrated Circuit (I2C) protocol is a serial communication protocol designed and developed by NXP semiconductors. I2C protocol is simple and hardware efficient bidirectional 2-wire bus which has the ability support multiple devices. Two wires used in I2C protocol are Serial Data Bus (SDA) and Serial Clock Line (SCL). SDA wire is used for data transfer and SCL is used to synchronise the data transfer on SDA line. I2C communication interface also allows data transfer between faster and slower devices by using clock stretching technique. Data transfer rate in I2C communication protocol may vary depending on the mode of operation (standard, high speed and ultra fast modes) of I2C protocol. I2C communication protocol requires only two wires to establish communication between two devices and ensures that there is no data loss by using Acknowledgement (ACK) signal. Whereas other communication protocols like Serial Peripheral Interface (SPI), USB, UART, RS-485, CAN etc. require more number of pin connections and signals between communicating devices which is major disadvantage in designing low-area Integrated Circuit (IC). SPI protocol does not support multiple masters to control the system bus which is another important advantage of choosing I2C protocol over SPI. UART protocol does not synchronise the data transfer between communicating devices. In this project single-master controller, slave controller and multi-master controller are designed using Verilog Hardware Description Language (HDL). Functionality of the single-master controller and multi-master controller support multiple slaves. Results are presented for single-master controller in both standard and ultra-fast modes (unidirectional) by simulating the design in Xilinx tool. Verification environment is created for both single-master controller and multi-master controller designs using System Verilog (SV) constructs. Working of single-master controller in both transmitter and receiver mode is verified using QuestaSim 10.0b tool. In the case of multi-master verification, working of bus arbitration technique is verified when two masters try to own the bus at the same time. Functional coverage obtained in the case of single-master verification and multi-master verification is 99.81% and 99.82% respectively. Assertion coverage is 100% in both the cases. Proposed method for verification is more efficient when compared to existing conventional methods in terms of functional coverage and assertion coverage.
Edla Maria Bezerra Lima Federal University of Rio de Janeiro, Brazil
Influence of the microstructure on the resistance of PLA biocomposites to food packaging using eco–friendly materials such as mango seed and organo montmorillonite minerals
Biocomposites based on PLA (matrix), organoclays and mango seed as loaded material has been developed by Casting in the present research group since 2015. The ongoing research modified the integument and the kernel of the mango seed by grinding it in a ball mill, reducing the particle size of the mango kernel six times (6X) compared to the original experiment, and fifty times (50x) the mango integument. This process eliminated the effect of elongated shape that the fibers present, increasing the specific surface in contact with the PLA. The samples were characterized in terms of physical-chemical properties (Laser Particle Size, SEM, XRD, Texturometer, FTIR), thermal properties and biodegradability. The SEM results showed that the chloroform output during drying process created bubbles/channels in the biopolymer matrix, which facilitated the access to fluids; weakened the material; and helped the process of biodegradability and decreased mechanical resistance to compression of biocomposites: PLA/integument, PLA/kernel, and PLA/integument/kernel, respectively in 79%, 86% and 84%. In addition, the biodegradability in water and soil was accentuated for the PLA/kernel biocomposite (since 1 week), followed by PLA/integument/kernel biocomposites (5 weeks) and PLA/integument (14 weeks) in a 19-week experiment. These experiments demonstrated that both, the increase in the specific load/matrix contact surface and the creation of bubbles/channels by purging gases during the Casting process, are efficient in accelerating the degradation of these biocomposites in nature and making them highly mechanically fragile. The addition of Bofe and Chocolate organoclay’s accelerated the degradation process of PLA, likely due to the presence of the hydroxyl groups belonging to the silicate layers surface and/or to their organic modifier. The biodegradation of PLA/kernel/integument/Bofe organoclay in water was higher than it was in soil. Furthermore, the materials added to the PLA matrix increased the crystallinity degree and the resistance of the obtained biocomposites.
Henrique José da Silva UNIFRAN - University of Franca, Brazil
Efficiency improvement of photovoltaic cells by coating the protection glass with a silica matrix co-doped with Er3+/Yb3+
This work concerns the power efficiency improvement of polycrystalline silicon photovoltaic cells, by
coating the glass which protects the cells, using thin films. The films were obtained by the Sol-Gel
process, with a silica matrix co-doped with Er3+/Yb3+ lanthanide ions, that promotes upconversion
from infrared to visible light. In this work the films coat the glass instead the cells, like was done in
previous studies1, because the films were treated at 300°C and it is easier to work with the coated
glass. The voltage, current and electrical power were analysed, for seven different samples: only the
photovoltaic cell; the cell protected with a 4 mm common cleaned glass; the cell with a similar glass
coated by one and two layers of thin film, submitted at 200ºC and 300ºC and with two different codoped
concentrations of Er3+/Yb3+. The commercial squared cells with dimensions 156 X 156 mm and
glasses as same dimensions were used. Firstly, the coated glass was submitted to excitation at 980 nm
at 300, 720 and 1090 mW laser power. Typical Er3+ emission bands emerged in the green region (2H11/2
to 4I15/2 and 4S3/2 to 4I15/2) and red regions (4F9/2 to 4I15/2). These results is an indication that the films
are present covering the glass substrate, and the upconversion occurs. After that, the glasses were
placed over the photovoltaic cell and exposed directly to the sun light. Experimental results showed
the efficiency improvement when the glass is coated with the thin film. This improvement is higher
with two layers and with a thermal treatment of 300°C. In conclusion, the photovoltaic cells efficiency
is low due to several factors such as, temperature and non-use of infrared radiation; the solution can
be the use of thin films with system to convert the infrared radiation in visible light.
Bikram Gautam University of Arkansas for Medical Sciences (UAMS), Little Rock, Arkansas, USA, Nepal
Assessment of Bacterial Load in Polyethylene Terephthalate (PET) Bottled Water
Reuse of polyethylene terephthalate (PET) bottles have been done to conserve nature, but due to increasing microbial load in the same reused bottle has been cause of many morbidity across the globe. The aim of this study is to determine any associations between bacterial load and the physical condition of the water bottle.
For this study, parameters like pH, electrical conductivity (EC), total dissolved solids (TDS), heterotrophic plate count (HPC), total coliform count, and Pseudomonas spp were assessed as per the American Public Health Association, 2005. For the extent of polymer degradation the base of the same PET bottle was subjected to FTIR analysis.
The pH value of water samples tested ranged from 5.2 to 6.8. The majority of samples (96%) were found to contain pH values that were unacceptable as per the Department of Food Technology and Quality Control (DFTQC) guideline. Value of electrical conductivity (EC) ranged from 5 to 199 μS/cm. HPC revealed that, out of 100 samples, 48 (48%) samples were found to be acceptable as per the DFTQC guideline value (<25 cfu/mL). Among 100 samples, Pseudomonas spp. was found to be present in 23% of bottled water. Acidic pH and elevated concentrations of TDS and EC may lead to the survival of extremophiles present in HPC which may lead to degradation of PET. FTIR analysis shows that the degradation is under process but has not occurred yet.
Microorganisms survive in bottled water as they have many nutrients required for the microorganism in ionic form. The bacteria that survive in bottled water for a long time rely on several survival mechanisms including evolutionary development (evo-devo) and can solely survive on complex polymers like PET.
Marcelo Machado Viana Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
Polydimethylsiloxanes-modified TiO 2 coatings: The role of structural, morphological and optical characteristics in a self-cleaning surface
The surface modification of TiO 2 thin films with hydrophobic agents has been a good strategy
to modulate the surface energy of this material, allowing it to be compatible with a wider
range of applications . This is a promising approach in the search for self-cleaning
properties, since it is expected that the modified films will exhibit photocatalytic and
superhydrophobic properties. In this work, the synthesis and characterization of TiO 2 thin
films modified with two different types of polydimethylsiloxane (PDMS): hydroxy (AHH)
and vinyl-terminated (AHV) were carried out. PDMS modification of TiO 2 thin films
occurred on two different routes. Route 1 was obtained from the deposition and subsequent
thermal treatment of neat TiO 2 thin films (anatase phase), followed by a surface
functionalization with a solution of PDMS in toluene. Route 2 is based on the preparation and
deposition of a sol-gel solution containing both TiO 2 and PDMS precursors. The thin films
prepared were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM),
X-ray photoelectron spectroscopy (XPS), diffuse reflectance and wettability tests. Vinylic
coatings showed a hydrophobic behavior, while hydroxy coatings proved to be hydrophilics.
PDMS-modification occurred by a covalent functionalization with the formation of Ti–O–Si
bonds to the AHH and Ti–O–C bonds to AHV hydrophobic agent. The wettability test
evidenced significant differences in the contact angle between a water drop and the sample
surfaces and, in the roughness, as evidenced by AFM. This study contributed to a better
understanding of a heterogeneous functionalization of TiO 2 thin films using a non-fluorinated
polymer as a hydrophobic agent and using a faster and environmentally friendlier procedure
for improved the self-cleaning coatings design.
Robert Streubel University of Nebraska-Lincoln, United States
Chiral Spin Textures in Amorphous Iron–Germanium Thick Films
Single-crystals and multilayer heterostructures with global inversion symmetry breaking can promote the formation of topological solitary vector fields owing to a vector spin exchange known as the Dzyaloshinskii-Moriya interaction (DMI). - And so can short-range order. - In this talk, I will present experimental evidence of 3D chiral spin textures, i.e., helical spins and skyrmions with different chirality and topological charge, stabilized in amorphous Fe–Ge thick films. Harnessing Lorentz microscopy with exit wave reconstruction, we observe both isotropic Bloch skyrmions (N = 1), previously found in B20 single-crystals, and anisotropic solitons, i.e., antiskyrmions (N = −1) and N = 2 skyrmions. X-ray magnetic circular dichroism (XMCD) spectroscopy suggests a short-range order similar to B20 FeGe single-crystals despite lacking a global broken chiral symmetry. Our results demonstrate that structurally and chemically disordered materials with a random DMI can resemble inversion symmetry broken systems with similar magnetic properties, moments, and states. Yet, disordered systems are distinct by their degenerate spin chirality that allows for forming isotropic and anisotropic topological spin textures at remanence while offering greater flexibility in materials synthesis, voltage and strain manipulation, and an enhanced spin-orbit coupling relevant to prospective microelectronics applications.
Steponas Ašmontas Center for Physical Sciences and Technology, Lithuania
Impact of cesium concentration on optoelectronic properties of metal halide perovskites
Metal halide perovskites attract considerable attention due to their superior properties having potential applications in optoelectronic devices such as solar cells, photodetectors, light emitting diodes. In solar cells, metal halide perovskites are atractive for their high absorption coefficient allowing to use a thin film, high defect tolerance, high carrier mobility, and long carrier diffusion length. Excellent band gap tunability allows using perovskite layer as a top sub-cell on any bottom cell. Currently, the best solar cells use a mixture of formamidinium (FA) and methylammonium (MA) as the monovalent cations. Addition of cesium makes the triple cation perovskite compositions more thermally stable as they have less phase impurities and are less sensitive to processing conditions.
The triple cation perovskite layers were formed by a one-step deposition method from the produced precursor solution. Anhydrous N,N-dimethylformamide/dimethylsulfoxide (DMF / DMSO), 4:1 by volume, was used as a solvent. Material concentrations of the prepared solution were: 1 M of formamidinium iodide FAI, 1.1-1.3 M of PbI2, 0.2 M of methylammonium bromide MABr, 0.2 M of PbBr. Then CsI solution (1.5 M of CsI in DMSO) was added to the prepared precursor, and CsI concentration was varied from 0 to 50%. The prepared precursor solution was used to form a perovskite compound Csx(MA0.17FA0.83)(100-x)Pb (I0.83Br0.17)3. The layers were deposited by means of programmable centrifuge. FTO glass covered with thin TiO2 film was used as a substrate. The perovskite layers were annealed for 60 min in an inert atmosphere at 100°C temperature.
In this communication, we present experimental study of optical properties of perovskite layers with different cesium concentration as well as photoelectric properties of solar cells fabricated on their base.
Zhou Bing Chen The Hong Kong Polytechnic University, China
Mechanisms for suppressing discontinuous precipitation and improving mechanical properties of NiAl-strengthened steels through nanoscale Cu partitioning
High-strength low-carbon steels are of considerable technological importance in engineering applications such as automotive, shipbuilding, and energy industries. Precipitation strengthening is an effective method for strengthening low-carbon steels. Among various potential precipitates used for precipitation strengthening, NiAl is one of the most effective phases to achieve high strength, and the precipitation of which occurs either continuously or discontinuously. Control of discontinuous and continuous precipitation is crucial for tailoring the microstructure and mechanical properties of NiAl-strengthened steels. In this talk, we will report that Cu is effective in not only promoting the nano-scale continuous NiAl precipitation but also in suppressing the coarse-scale discontinuous NiAl precipitation at grain boundaries, which results in the development of new NiAl-strengthened steels with high yield strength (1400 MPa) and good ductility (10%). Our analyses indicate that the mechanisms for suppressing discontinuous NiAl precipitation are twofold. The main one is the acceleration of continuous NiAl precipitation through Cu partitioning, which swiftly reduces the matrix supersaturation, thereby decreasing the driving force for the growth of discontinuous precipitation. The other is the reduction of grain boundary energy through Cu segregation, which is likely to decrease the nucleation rate of discontinuous precipitation. Consequently, Cu increases the number density of NiAl nanoparticles by more than fivefold, which leads to a twofold enhancement in the strengthening and an improvement in the over-aging resistance of NiAl-strengthened steels.
Yizhaq Engelberg Israel Institute of Technology, Israel
Functional helical fibrils of the human antimicrobial peptide LL37(17-29) present novel architecture and thermal stability
Antimicrobial peptides (AMPs) are canonical part of the innate immune system of many organisms in all kingdoms of life. Interestingly, certain AMPs assemble into well-ordered fibrils that resemble amyloids, which are proteins associated with neurodegenerative and systemic diseases and which bear unique material properties. LL-37 is an AMP which is expressed by various mammalian cells and is considered to play an important role in the first line of defense against pathogens. hLL-37 is cleaved in-vivo into many active derivatives which show a diverse array of selectivity against microbial strains, and additional functions within the immune system. The hLL-3717-29 13-residue derivative was suggested to serve as the active core of hLL-37. Using X-ray micro-crystallography and electron microscopy techniques, we revealed the supra-helical, fibril structure of hLL-3717-29, and correlated between its self-assembly and antibiotic activity. We also determined the high stability of the fibril’s upon heating, and based on these findings, we are working towards the design novel fibril-forming AMPs with improved shelf life and stability. In addition, we are developing an approach to allow the control over their activity and selectivity upon demand.
Dr. Madhumita Mukhopadhyay Amity University, India
Interaction of Macrocyclic Zn (II) Schiff Base cationic Surfactant: A Study using Photometric and Theoretical Approach
A 48 membered macrocyclic tetranuclear Zn (II) complex is reported to be a complex dual anion sensor for fluoride and acetate in aqueous methanolic solution by change in absorption as well as by fluorescence enhancement. In this context, study on the interaction of such Schiff base viz. tetranuclear complex cation [Zn4(LH3)(NO3)5]2+ with a bio-mimicking surfactant is an interesting approach for pursuing detailed study on medicinal industry owing to their antibacterial, antifungal, antiviral activities. A widely used bio mimicking membrane like cetyl trimethyl ammonium bromide (CTAB) is undertaken by the present researchers to study the respective interactions with the functional Zn (II) complex. Steady state absorption and emission studies have been pursued to investigate the course of deciphering the photophysical behaviour of the complex. The extent and mode of binding of the Schiff base with CTAB is analysed using the binding constant magnitude. The extent of interaction among the experimental complex and the biomimicking surfactant is also studied using frontier molecular approach upon engaging ab initio quantum calculations. Hence, analysing the mode of interaction with CTAB, further study is designed for such Schiff base with a suitable bio protein for necessary application in future.
Ana Paula Domínguez Rubio University of Buenos Aires, Argentina
Bacillus subtilis extracellular vesicles can be transported through an in vitro intestinal epithelial cell model
Bacterial Extracellular Vesicles (EVs) have been related to inter-kingdom communication between probiotic/pathogenic bacteria and their hosts. The gastrointestinal tract (GIT) mucosal surface is the primary interface between gut bacteria and internal host tissues. A vital communication between kingdoms in the mammalian GIT is supposed to occur through an exchange of EVs that may interact in a triangular way between gut bacteria and the host. Our aim was to investigate the transcytosis process of B. subtilis EVs using an in vitro intestinal epithelial cell model. In this study, using Confocal Laser Scanning Microscopy, we report that uptake and internalization of CFSE-labeled B. subtilis EVs (115 nm ± 27 nm) by Caco-2 cells are time-dependent. To study the transcytosis process we used a transwell system and EVs were quantified in the lower chamber by Fluorescence and Nanoparticle Tracking Analysis measurements. Intact EVs are transported across a polarized cell monolayer at 60–120 min and increased after 240 min with an estimated average uptake efficiency of 30% and this process is dose-dependent. EVs movement into intestinal epithelial cells was mainly through Z axis and scarcely on X and Y axis. This work demonstrates that bacterial EVs could be transported across the gastrointestinal epithelium. Our findings suggest that this mechanism could be the first step allowing EVs to reach the bloodstream for further delivery up to extraintestinal tissues and organs. The expression and further encapsulation of bioactive molecules into these natural nanoparticles produced by probiotic bacteria EVs of GRAS (Generally Recognized as Safe) bacteria could have practical implications in food, nutraceuticals and clinical therapies.
Liwen Sang National Institute for Materials Science, Japan
Photoelectricity energy conversion devices based on III-V Nitride semiconductors
III-Nitride semiconductor InxGa1-xN has the unique advantage of the widest adjustament
of direct bandgaps from infrared (InN at 0.65 eV) to ultraviolet (UV) (GaN at 3.42 eV) region.
Compared with Si, GaAs, CuInGaSe or Ge systems, it is the only semiconductor system that
can provide the perfect match to the solar spectrum. On the other hand, InGaN-based alloys
also have the favorable physical properties of high absorption coefficient (~105cm-1), high
radiation resistance, high drift velocity, and high carrier mobility. These properties provide
them the promising candidate in the photoelectricity energy conversion devices, not only LED
or LDs, but also the high-performance photodiodes, and solar cells.
In this paper, we will report our work on the photoelectricity devices based on III-Nitride
InGaN film. The word-record visible-blind photodiodes were achieved by using InGaN with
CaF2 as the insulation layer. For the InGaN solar cells, we firstly propose the concept of
intermediate-band transitions based on Nitride, and successfully extend the photoresponse
spectrum from deep UV the near infrared region.
Tailoring diffusive pathways and thermal expansion in Ti-alloys
Ti-alloys are key materials in aerospace and biomedical engineering. Central for the optimization of their mechanical and functional behavior is in-depth knowledge on the complex interplay between diffusive and displacive phase transformations. Recently, 2 intriguing discoveries in relation to orthorhombic α″ phases in β-stabilized Ti-alloys were made: (i) the diffusion-controlled formation of α″iso , α″lean and α″rich phases and ii) the giant and highly anisotropic thermal expansion of martensitic α″. Insight into both phenomena is limited, however needed for the tailoring of (micro)structures across a wide spectrum of configurations.
To address this challenge, I will demonstrate that the thermodynamic energy landscape reveals formation pathways for the diffusional forms of α″ and may lead to a stable β-phase miscibility gap in the binary Ti-Nb alloys. In this way, temperature-composition criteria for the occurrence of α″iso and resolve reaction sequences during thermal cycling are derived. Further, I will revisit the giant (linear) thermal expansion in Ti-Nb alloys and will discuss processing routes to obtain null linear expansion in Ti-alloys. The presented concepts are expected to be transferable to other Ti-alloys and to catalyze new avenues for their tailoring and technological exploitation.
Mao Mao The University of Hong Kong, China
Stable, High-Efficiency Voltage-Dependent Color-Tunable Organic Light-Emitting Diodes with a Single Tetradentate Platinum(II) Emitter Having Long Operational Lifetime
Voltage-dependent, color-tunable organic light-emitting diodes (OLEDs) are appealing tools that can be used for the visualization of electronic output signal of sensors. Nonetheless, the literature reported color-tunable OLEDs that have a simple single-cell device structure suffer from relatively low efficiency, pronounced efficiency roll-off, color-aging, and short operation lifetime, all of which limit practical applications. Here we describe a novel co-host-in-double-emissive-layer (CHIDEL) device, designed to enhance the performance of color-tunable OLEDs with the use of a single tetradentate Pt[O^N^C^N] emitter. When Pt-X-2 was used as a single emitter in an optimized CHIDEL device, a white OLED with CIE tunable coordinates from (0.47, 0.44) at 3 V to (0.36, 0.48) at 11 V, a high color rendering index of 82, and high EQEs of up to 20.75% could be achieved. By using Pt-X-4 as a single emitter, the voltage-dependent color-tunable CHIDEL device, with CIE coordinates shifted from (0.56, 0.43) at 3 V to (0.42, 0.55) at 11 V, demonstrated a high luminance of beyond 90000 cd m-2 and a high EQE of 23.23% at a luminance of 1300 cd m-2. A long lifetime (LT90) of almost 20000 h has been demonstrated for the color-tunable OLED with Pt-X-4 emitting dopant.
Marcello Rubens Barsi Andreeta Federal University of São Carlos, Brazil
Combining single crystal fibers and ceramics to enhance ionic conductivity in solid-state electrolytes
The Laser-Heated Pedestal Growth (LHPG) technique emerged as an attempt to reduce
costs and to enhance the research on solid-state optical devices. The technique allows a fast
way to produce a wide variety of oxide compounds in a fiber-shaped single crystal (known as
single crystal fiber - SCF). Although the main technological applications were regarded to the
optical field, other works were successful in combining SCFs and ceramic materials with
applications ranging from structural reinforcement to textured piezoelectric materials. Another
very important field to be explored, regarding the combination of ceramic materials and SCFs,
is the solid-state electrolytes for low cost, clean and sustainable energy production. Nowadays,
regarding solid-state electrolytes, lithium lanthanum titanate (LLTO) and yttria-stabilized
zirconia (YSZ) are concentrating most of the research efforts. However, several technological
and scientific challenges still remain to be overcome regarding grain boundary engineering
and/or temperature of operation of the devices. In the case of LLTO ceramics, the processing
difficulties and its compositional and crystallographic nature remains a challenge for mass
production. In the case of YSZ, high efficiency of the solid oxide fuel cells (SOFCs) is only
achieved at high temperatures (T>800°C), leading to technological problems regarding the
electrodes. In this work, a new design is presented in order to increase the ionic conductivity
of LLTO and YSZ electrolytes by creating hetero (SCF-LaAlO3:LLTO) and homointerfaces
(SCF-YSZ:YSZ) between SCFs and the polycrystalline ceramic matrix, interconnecting the
two electrodes through those interfaces. The results indicate that it is possible to get an
enhancement of the effective ionic conductivity higher than 200%, which would allow the
production of a more efficient batteries and may provide the decrease in the SOFCs operation
temperature, compared to the conventional ceramics.
Matthew Gleeson Institute Polytechnqiue Paris, France
Quantifying the effect of morphology on second harmonic generation in glycine micro needles
Second harmonic generation (SHG) in crystalline materials can be utilized in nonlinear photonic devices with frequency conversion, multiplexed signal transmission and waveguiding. Organic crystals have useful properties such as ease of synthesis, birefringence, wide transparency range coupled with high molecular polarizability due to a pi-conjugated bond system that allows for large deformation in the presence of an electric field. Isolating the material property responsible for nonlinear optical effects, the second order susceptibility tensor χ(2), is often complicated by crystal growth directions, morphology and frame rotations. Finding and accurately quantifying χ(2) is key for material choice and device design. With recent advances in growing well defined micro and nanoscale structures, the effect of morphology and internal asymmetries on the recovery of χ(2) is relatively unexplored.
We developed a quantitative framework and analytical approach to recover the elements of χ(2) using polarization-resolved SHG microscopy in transmission mode, while illustrating the effect of morphology and birefringence on χ(2) elements. This is applied to non-centrosymmetric β and γ phase microneedles of the amino acid Glycine. Microneedles are grown via droplet evaporation, then characterized with Raman spectroscopy, X-Ray diffraction and Coherent Anti-Stokes Raman Scattering microscopy. The maximum χ(2) elements recovered were d33 = 15 pm/V and d33 = 5.9 pm/V for the β and γ phases respectively. Accounting for the microneedle morphology shows an increased contribution of the longitudinal tensor elements at the expense of others. Our results demonstrate Glycine as a useful bio-compatible nonlinear material.
Anna Bezryadina California State University of Northridge, United States
Nonlinear self-trapping and guiding of light in biological suspensions
The study of nonlinear processes in biological samples is crucial for developing new methods for fabrication of new bio-photonics devices and for developing low-loss transmission for deep-tissue imaging. In the last decade, significant work was to study deep-penetration of light and formation of optical waveguides in dielectric and metallic colloidal suspensions with tunable polarizability. In this work, we discuss formation of waveguide structures in biological suspensions for a range of wavelengths. Specifically, several centimeters long biological waveguides, with no significant photodamage of the cells, have been successfully demonstrated in colloidal suspensions of cyanobacteria, E. coli, and red blood cells (RBCs).
According to the forward-scattering theoretical model, cells in colloidal suspensions get attracted toward the center of the beam due to the optical gradient force, and simultaneously move along the laser beam due to the scattering force. Since living cells usually have a slightly higher index of refraction than the surrounding media, the optical force-induced nonlinearity leads to a self-lensing effect along the beam path, which allows for the formation of a biological "fiber".
Biological samples often have various absorption bands that need to be either targeted or avoided in opto-fluidic micromanipulation or biomedical imaging. However, sometimes the preferred wavelengths may not be suitable to exhibit nonlinear self-guiding and waveguide formation. To overcome this challenge, we implement a pump/probe-type nonlinear coupling, where formed biological waveguides provide effective guidance for a weaker laser beam. Finally, we investigate the conservation of polarization and orbital angular momentum through these scattering bio-soft-matter suspensions. We expect that these studies will help in developing alternative solutions to transmit energy and information through scattering media, as needed in communications, deep-tissue imaging, treatment and diagnostics.