Materials Science

For a drug with low bioavailability, a matrix tablet with liquid permeation enhancer (Labrasol®) was formulated. Factorial design was used to evaluate the effect of three formulation factors: drug percentage, polymer type (Methocel® K100M or Eudragit® L 100-55), and tablet binder percentage (Plasdone® S-630) on tablet characteristics. Tablets were prepared by direct compression and characterized. Compressibility index values ranged between 15.90% and 29.87% and tablet hardness values from 7.8 to 29.78 Kp. Eudragit®-containing formulations had better compressibility index values with higher tablet hardness. Time for 75% of drug release (T 75 ) was calculated, and formulations containing Eudragit® L 100-55 had faster release rates than tablet formulations with Methocel® K100M. Formulations with Methocel® K100M fit well in the Higuchi model as indicated by their R 2 values (>0.98). Among all the formulation factors studied, polymer type displayed the highest and statistically significant effect on compressibility index, tablet hardness, and dissolution rate. Statistical design helped in better understanding the effect of formulation factors on tablet characteristics important for designing formulations with desired characteristics.

Capacitive sensors are essential to promoting modernization and intelligence in agriculture. With the continuous advancement of this sensor technology, the demand for materials with high conductivity and flexibility is rapidly increasing. Herein, we introduce liquid metal as a solution for the in-site fabrication of high-performance capacitive sensors for plant sensing. As a comparison, three pathways have been proposed for the preparation of flexible capacitors inside plants, as well as on their surfaces. Specifically, concealed capacitors can be constructed by directly injecting liquid metal into the plant cavity. Printable capacitors are prepared via printing Cu-doped liquid metal with better adhesion on plant surfaces. A composite liquid metal-based capacitive sensor is achieved by printing liquid metal on the plant surface and injecting it into the interior of the plant. While each method has limitations, the composite liquid metal-based capacitive sensor provides an optimal tr...

Corresponding Author: M. Fadhali, Institute of advanced Photonic Sciences, Faculty of Science University Technologyi Malaysia, 81310 Skudai, Johor, Malaysia. Fax: 006075566162 E-mail: mohamedfadhali@yahoo.com 1778 ... Analysis of Efficiency and Misalignment ...

A custom bench-scale continuous-flow catalytic fast-pyrolysis (CFP) 2 reactor system was implemented for the optimization of ex situ CFP and screening of 3 catalysts to gain insight into commercial scale ex situ CFP processes across various 4 reactor types. Operated in an ex situ configuration, tandem laminar entrained-flow 5 pyrolyzer and vapor-phase upgrading reactors were optimized to successfully 6 demonstrate CFP of pine over two different commercial zeolite catalysts. Mixing-7 enhancers within the vapor-phase upgrader induced laminar flow dynamics with larger 8 Reynold's numbers, thus enhancing heat and mass transfer and in turn CFP 9 conversion. Real-time analysis of products was accomplished via molecular beam mass 10 spectrometry (MBMS), while light gas yield was determined using non-dispersive 11 infrared (NDIR) analysis. The transfer of the pyrolysis vapors to the vapor-phase 12 upgrader was investigated to gain insight into optimal transfer-line conditions for limiting 13 secondary thermal cracking and preserving carbon in the ex situ CFP process. The 14 products were comparable to those previously obtained from fixed bed and fluidized bed 15 reactor systems as well as entrained-flow riser reactor systems (e.g., one-ring 16 aromatics, polyaromatics, and phenolics). Replicate experiments demonstrated a good

A custom bench-scale continuous-flow catalytic fast-pyrolysis (CFP) 2 reactor system was implemented for the optimization of ex situ CFP and screening of 3 catalysts to gain insight into commercial scale ex situ CFP processes across various 4 reactor types. Operated in an ex situ configuration, tandem laminar entrained-flow 5 pyrolyzer and vapor-phase upgrading reactors were optimized to successfully 6 demonstrate CFP of pine over two different commercial zeolite catalysts. Mixing-7 enhancers within the vapor-phase upgrader induced laminar flow dynamics with larger 8 Reynold's numbers, thus enhancing heat and mass transfer and in turn CFP 9 conversion. Real-time analysis of products was accomplished via molecular beam mass 10 spectrometry (MBMS), while light gas yield was determined using non-dispersive 11 infrared (NDIR) analysis. The transfer of the pyrolysis vapors to the vapor-phase 12 upgrader was investigated to gain insight into optimal transfer-line conditions for limiting 13 secondary thermal cracking and preserving carbon in the ex situ CFP process. The 14 products were comparable to those previously obtained from fixed bed and fluidized bed 15 reactor systems as well as entrained-flow riser reactor systems (e.g., one-ring 16 aromatics, polyaromatics, and phenolics). Replicate experiments demonstrated a good

A series of Dy-doped Li-Ni ferrites of the following composition Li 0.5 Ni 0.48 Tb 0.02 Dy x Fe 2-x O 4 (0.2≤x≥0) was synthesized by the microemulsion method. The X-ray diffraction (XRD) analysis indicated that Li 0.5 Ni 0.48 Tb 0.02 Dy x Fe 2-x O 4 nano-crystalline ferrites exhibited the single-phase spinel structure. The lattice parameter was determined by the Nelson-Riley refinement technique and it increased by increasing the Dy contents. The crystallite size was computed from the Debye Scherrer's formula and it was in range from 27 to 40 nm. The thermal decomposition process was studied by the thermogravimetric analysis and the annealing temperature observed was 980 °C. The real and complex parts of dielectric constant decreases very sharply in the lower frequency region, but in the higher frequency region, the real and complex part of dielectric constant show variable values with Dy contents. The dielectric tangent loss (tan δ) decreases exponentially with Dy contents. The magnitude of the ac conductivity decreases in certain frequency region, as the Dy contents are increased. The possible mechanisms contributing to the above behavior are discussed. The results of these nanocrystalline ferrites are very suitable materials for microwave device applications.

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Technology means application of knowledge for practical requirements. The present technology is running towards the highest peak of advancement that brings the irreversible damage to our earth. We know that every invention has its pros and cons but we merely ignore its disadvantages which are indeed disturbing human life as well as animal habitats. Thus Green Technology aims to save our planet by utilizing renewable resources which never depletes. It is also used to minimize the effect of environmental pollution by replacing waste products by renewed products so that the greenery is increased and we can go green. It has various branches like Green Electricity, Green Nanotechnology, Green Buildings, and Green Chemistry etc. Each of them has no negative effects, thus the future generation can be benefited from them. As we pollute this planet, we are sole responsible to save it from its destruction. This paper mainly focuses on the need, importance and advantages of Green Technology fo...

This project presents the Designing of Transformer and Induction Motor. Mathematical equations are used for the designing of Transformer and Induction Motor. They help in determining the dimension and electrical parameters which will satisfy specifications such as rating of machine, speed of the machine, etc. used for design. But the design calculation can be a hectic process when done manually. Since the calculation is long and interdependent with each steps the occurrence of error is more likely. Python programming language is adopted for fast computation, to simplify the process and to minimize this error. The program is designed in such a way that allows the user to enter the main specification of the machine. The program performs the calculation required thus allowing the user to obtain the results. In addition, the software would be useful for the education and research purpose.

Fabrication of Cu/TiO 2 nanocomposite had been successfully performed. A nanocomposite was prepared by the insertion of metal (copper) in the TiO 2 nanoparticles. Cu/TiO 2 nanocomposite was deposited on the FTO glass used the spin coating method. Layers of Cu/TiO 2 nanocomposite were prepared in variations at 1, 2 and 3 layers. Spektrofotometer UV-VIS Lamda 25 was used to determine the optical characteristics and the energy gap of DSSC materials. El kahfi 100/I-V Meter and Keithley 2602A was used to determine the electrical properties of Cu/TiO 2 nanocomposite. UV-VIS result was showed that there increased absorption wavelength of Cu/TiO 2 nanocomposite and were able to decrease the energy gap. El kahfi was showed that the conductivity of the Cu/TiO 2 nanocomposite was 3.71x10 -2 (Ω -1 m -1 ). Keithley was showed that the highest efficiency in the 3 layers of Cu/TiO 2 nanocomposite of 0.011%.

Discussions on socially and culturally dominant values, beliefs and practices pertaining to patient’s health and culture are not isolated but integral to the practice of contemporary clinical medicine. Medical anthropologists play a unique role in redefining and repositioning the application of CAM in biomedical sciences. This article addresses the current state of knowledge regarding the distinction between medical anthropology and complementary and alternative medicine (CAM). Participant observations of, and in-depth interviews with ten Malaysian Chinese women cancer survivors were carried out to study their CAM use during and after cancer treatment. The results provide insights about the patterns of CAM use as well as the social and cultural factors under-pining the choice of CAM used by cancer survivors before and after treatment. The survivors’ preference for CAM use during cancer diagnosis was found to be influenced by their values, beliefs, and practices with respect to five ...

Se prepararon sólidos micro/mesoporosos del tipo MOR/MCM-41, con diferentes relaciones Si/Al. Para esto se colocó 3,15g de zeolita en solución de NaOH 3M y se agitó la suspensión por 30 min. Luego se agregaron 40 g de una solución de bromuro de hexadeciltrimetil-amonio (CTAB al 16% p/p) y se agitó por 30 minutos nuevamente. La mezcla fue depositada en un reactor de acero revestido de teflón y tratada hidrotérmicamente a 373 K por 24 h. Después de esto, el pH fue ajustado a 8,5. La mezcla fue depositada nuevamente en el reactor por 24 h más a 373 K. El producto sólido fue recuperado por filtración y se lavó con etanol y agua desionizada, para posteriormente secarlo en aire a 353 K y luego calcinarlo 6 h a 823 K. La forma ácida de estos sólidos fue obtenida mediante intercambio iónico en solución de NH NO 1 M a 343 K. Esos compuestos fueron caracterizados por MEB, EDX, DRX, TGA 4 3 y adsorción de N . Los sólidos obtenidos presentan áreas superficiales y volúmenes de poro

Polymorphs of Zn(2-nIm) 2 (compound 1) and Co(2-nIm) 2 (compounds 2 and 3) (2-nIm = 2nitroimidazole) have been prepared by two routes: solvothermal synthesis and recrystallisation of ZIF-65(Zn/Co). Compounds 1 and 2 are isostructural, with a tetrahedrallyconnected framework topology related to, but different from, that of tridymite (lonsdaleite). Single crystal X-ray diffraction analysis showed that in compound 1 (Pccn, Z = 8; a = 8.462(8) Å, b = 14.549(15) Å, c = 18.799(18) Å, V = 2314(4) Å 3 ) there is rotational disorder for two of the three crystallographically-distinct linker types, which has been investigated computationally and by solid-state NMR spectroscopy. Detailed adsorption studies on a sample of 1 prepared by recrystallisation show 1.1 mmol g -1 uptake of CO 2 at 0.1 bar (25 °C) with high affinity for CO 2 over CH 4 and N 2 (adsorption enthalpies of 39.5, 26.0 and 18.5 kJ mol -1 , respectively). A cobalt analogue (compound 2) with improved water stability (but lower porosity) has also been prepared. Changing the conditions of synthesis and recrystallisation gives rise to a cobalt 2-nitroimidazolate (Co(2-nIm) 2 , compound 3), which has a layered structure (I4 1 /amd, a = 6.025(18) Å, c = 26.95(8) Å, V = 978.3(5) Å 3 ) containing sheets of tetrahedrally-connected Co 2+ cations composed of four membered rings, without porosity.

Qilei Song1,4, Shuai Cao2, Shan Jiang3, Andrew I. Cooper3, Anthony K. Cheetham2, and Easan Sivaniah1,5 Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK Department of Chemistry, University of Liverpool, Liverpool UK Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto 606-8501, Japan Email: q.song@imperial.ac.uk

The perceptions of absolute scarcity of forest based cellulosic materials and high anticipated demand for paper appear to have been responsible for the policy emphasis on unconventional materials for paper and newsprint making in India. Among the unconventional materials, bagasse has been emphasized through fiscal incentives including excise duty exemptions. Based on a study of seven bagasse based paper and newsprint units, Tirath Gupta and Vinod Ahuja show that enhancing residual bagasse through drying it before firing the boilers and using that material for pulping would be more desirable compared to generating surplus bagasse by installing coal fired boilers at sugar mills. The most desirable and sustainable solution in the long- run, according to them, would be to integrate the production processes of paper and cellulosic materials.

The critical exponents and magnetocaloric properties of La 0.7 Sr 0.3 Mn 1Àx Ti x O 3 with x = 0 and 0.05 have been explored via magnetic measurements. The magnetic data analyzed in the critical region by using modified Arrott plots, the Kouvel-Fisher method, and the scaling hypothesis reveal values for the critical parameters of b = 0.3165 and 0.3027, c = 1.1121 and 1.203, and d = 4.7556 and 4.833 for x = 0 and x = 0.05 respectively. These values are in agreement with the three-dimensional (3D) Ising model. The n values obtained from the law DS max ¼ aðl 0 HÞ n are 0.648 and 0.685. The maximum values of the magnetic entropy change are 1.65 J/kg K and 1.46 J/kg K under a magnetic field change of 10 kOe for x = 0.00 and 0.05, respectively. These results can be explained in the scenario of the short-range interaction and the phase separation as well as the diluted magnetic effect in manganites.

In the present article, we report a study on the mechanical behaviour displayed by hydrogen atoms and pores in silicon nitride (SiN) films. A simple three-phase model is proposed to relate the physical properties (stiffness, film stress, mass density, etc.) of hydrogenated nanoporous SiN thin films to the volume fractions of hydrogen and pores. This model is then applied to experimental data extracted from films deposited by plasma enhanced chemical vapour deposition, where hydrogen content, stress, and mass densities range widely from 11% to 30%, À2.8 to 1.5 GPa, and 2.0 to 2.8 g/cm 3 , respectively. Starting from the conventional plotting of film's Young's modulus against film porosity, we first propose to correct the conventional calculation of porosity volume fraction with the hydrogen content, thus taking into account both hydrogen mass and concentration. The weight of this hydrogen-correction is found to evolve linearly with hydrogen concentration in tensile films (in accordance with a simple "mass correction" of the film density calculation), but a clear discontinuity is observed toward compressive stresses. Then, the effective volume occupied by hydrogen atoms is calculated taking account of the bond type (N-H or Si-H bonds), thus allowing a precise extraction of the hydrogen volume fraction. These calculations applied to tensile films show that both volume fractions of hydrogen and porosity are similar in magnitude and randomly distributed against Young's modulus. However, the expected linear dependence of the Young's modulus is clearly observed when both volume fractions are added. Finally, we show that the stiffer behaviour of compressive films cannot be only explained on the basis of this (hydrogen þ porosity) volume fraction. Indeed this stiffness difference relies on a dual mechanical behaviour displayed by hydrogen atoms against the film stress state: while they participate to the stiffness in compressive films, hydrogen atoms mainly behave like pores in tensile films where they do not participate to the film stiffness. V

Mn doping of group-IV semiconductors (Si/Ge) is achieved by embedding nanostructured Mn-layers in group-IV matrix. The Mn-nanostructures are monoatomic Mn-wires or Mn-clusters and capped with an amorphous Si or Ge layer. The precise fabrication of δ-doped Mn-layers is combined with element-specific detection of the magnetic signature with x-ray magnetic circular dichroism. The largest moment (2.5 μB/Mn) is measured for Mn-wires with ionic bonding character and a-Ge overlayer cap; a-Si capping reduces the moment due to variations of bonding in agreement with theoretical predictions. The moments in δ-doped layers dominated by clusters is quenched with an antiferromagnetic component from Mn–Mn bonding.

The combination of Si and Ge with Mn is a critical step in the development of novel spintronics devices. We investigate the magnetic doping of Si, Si-surfaces and Ge- quantum dots with Mn. A surface-driven route is used for the addition of Mn and allows a stringent control of the Mn-Si and Mn-Ge interaction. The evolution of nanostructures is observed

The magnetic doping of group IV semiconductors and quantum dots is a critical to combine charge and spin driven devices. The incorporation of the magnetic element Mn is hampered by low solubility and competition with compound formation. The primary step in our surface driven approach to Mn-incorporation in a semiconductor matrix is the adsorption of Mn on the Si(100), Ge(100)

A novel optoelectrofulidic system integrated optical image concentration and alignment system, dielectrophoresis phenomenon, microfluidic and friendly real-time control interface is first reported in this article. A new application of photoconductive material oxotitanium phthalocyanine (TiOPc) for microparticle applying has been first described and demonstrated by our research group. Basis on the special character of the photoconductive material, a TiOPc-based optoelectronic tweezers (Ti-OET) is utilized for single and massive cells/particles manipulation. The objects wanted to be manipulated are defined with different behaviors (e.g., press, release, drag and move) using Flash® software when the cursor acts on them. It also reveals the application for biological application to form the cells trapping with three sorts of cells, HMEC-1, HepG2 and HEK293t. Another application of our optoelectrofulidic system is to fabricate a TiOPc-based flow cytometry chip which can be used for sorting the 15μm diameter particles with 105 μm/s velocity. When the 10Vp.p. voltage and 45 kHz AC frequency apply on the top and button ITO electrode, the illuminated light pattern will become a spatially virtual switch inside the microchannel. The dielectrophoresis force between top ITO glass and button photoconductive layer controlled by the friendly interface will concentrate the cells/particles as a straight line and individually direct each one in different paths. In summary, we have established an optoelectronfulidic-based chip and spatially virtual switch system which are applied for cell pattern and particles sorting. In the future, this easy manipulation approach can place the full power of optoelectronfulidic chip into the biological operators' hands.

This paper reports a fabrication technology which integrates organic opto-electrowetting (OEW) with PEGDA-based microfluidics between stacked ITO glass chips for droplets generation and manipulation. Organic OEW can be realized by using titanium oxide phthalocyanine (TiOPc) as a photoconductive layer. Optical images can be projected on an organic OEW area to induce the local virtual electrodes which reduce the surface energy for actuating droplets. Low-molecular-weight (LMW) PEGDA (poly(ethylene) glycol diacrylate) material is used to form stable and biocompatible microchannels between the stacked ITO glass chips by UV photopolymerization process. PEGDA-based microfluidics provides a simpler way to enhance droplets applications in organic OEW. We demonstrate (1) the droplet formation in PEGDA microstructure, (2) the motion of droplet-in-air and droplet-in-oil operated by TiOPc OEW in this platform. This technology requires only spin-coating and UV exposure and is more cost-effective than previous methods.

We develop light-driven optoelectronic tweezers based on the organic photoconductive material titanium oxide phthalocyanine. These tweezers function based on negative dielectrophoresis (nDEP). The dynamic manipulation of a single microparticle and cell patterning are demonstrated by using this light-driven optoelectronic DEP chip. The adaptive light patterns that drive the optoelectronic DEP onchip are designed by using Flash software to approach appropriate dynamic manipulation. This is also the first reported demonstration, to the best of our knowledge, for successfully patterning such delicate cells from human hepatocellular liver carcinoma cell line HepG2 by using any optoelectronic tweezers.

Magnetic beads are widely utilized for separating biomolecules, DNA and RNA. Traditionally, bulk magnet is utilized for manipulation these particles but when it comes to microscale bulk magnet is not the efficient method. Here, we utilize an organic photoconductive material, TiOPc, to generate light-induced electro-osmosis flow on chip. The fabrication process is convenient to be handled by the researchers and biologists without cleanroom IC fabrication facility. When specifically designed light pattern is projected onto the TiOPc substrate, the conductivity of the organic material layer within the illuminating region increases and the charges are locally assembled on its surface to form a virtual electrode. With an external ac voltage of 5 Vpp at 10 kHz, numerous magnetic beads are attracted from the nonilluminating region toward the center of light-pattern illuminating region. Driven by the moving light image, the grouped magnetic beads can be manipulated and merged in a desired way or direction. The light manipulation process provides a flexible and convenient approach for in vitro control of magnetic beads. We expect that this light-driven technology would display a multifunctional platform for manipulation of microparticles.

Microbubbles have a variety of applications in science and biological technology. Here, we demonstrate the manipulation of the picoliter gas bubble (picobubble) based on the optoelectronic-mechanism. The organic photoconductive material, titanium oxide phthalocyanine (TiOPc), was developed to make the light-sensitive substrate of this optoelectronic chip. The virtual electrodes are formed by projecting the dynamic light pattern onto TiOPc layer for generating the desired nonuniform electric field. The picobubble suspended in silicone oil can be manipulated with the velocity of 40–50 μm/s. The driving force up to 160 pico-Newtons could be generated for manipulating a gas bubble of 300 picoliters.

This paper reports on an optoelectrofluidic platform which consists of the organic photoconductive material, titanium oxide phthalocyanine (TiOPc), and the photocrosslinkable polymer, poly (ethylene glycol) diacrylate (PEGDA). TiOPc simplifies the fabrication process of the optoelectronic chip due to requiring only a single spin-coating step. PEGDA is applied to embed the moldless PEGDA-based microchannel between the top ITO glass and the bottom TiOPc substrate. A real-time control interface via a touch panel screen is utilized to select the target 15 μm polystyrene particles. When the microparticles flow to an illuminating light bar, which is oblique to the microfluidic flow path, the lateral driving force diverts the microparticles. Two light patterns, the switching oblique light bar and the optoelectronic ladder phenomenon, are designed to demonstrate the features. This work integrating the new material design, TiOPc and PEGDA, and the ability of mobile microparticle manipulation...

This paper reports the organic optoelectronic platform which integrates optoelectrowetting (OEW) and optoelectronic tweezers (OET) by spin-coating titanium oxide phthalocyanine (TiOPc) as a photoconductive layer for realizing the manipulation of cells and the actuation of droplets in a single chip.

This paper proposes a novel reconfigurable microstrip antenna with circularly polarized beam scanning feature. It is based on a microstrip Yagi-Uda antenna of two square patches. One patch is driven with two orthogonal feeds and the other is a parasitic. The parasitic patch is loaded with four lumped varactors and a DC biasing network, to effectively change its electrical size. Because the main beam direction is determined by the electrical size of the parasitic patch, electronic beam scanning is allowed by changing the capacitance value through the applied DC voltage. Operating at 2.45 GHz, the antenna shows a beam scanning range from -36 to 32 with 2.3 dB gain variation across the entire scanning range and gain peak value of 8.1dBi.

A selective ink deposition method is proposed for fabricating inkjet-printed passive UHF RFID tag antennas with optimized cost-performance ratios. The deposition method is based on identifying areas with high surface current densities on a given tag antenna and applying additional silver nanoparticle ink onto such areas to increase tag read range. In this paper, the proposed method is experimentally verified by utilizing the method on a small dipole tag antenna. Several ink deposition schemes are created, and their read range performances and ink consumptions are presented.

A numerical analysis of two-conductor transmission line with a rectangular notch in the dielectric between the strips is presented. Three media integral equations are derived and solved for the charge distributions. The decoupling between such twoconductor coupled microstrip transmission line is investigated for asymmetric conductors. It is found that the coupling between two conducting lines can be reduced significantly by removing dielectric material between the lines which has a rectangular shape. For best decoupling, the width should be as wide as possible between the conducting lines but the depth should have an optima somewhere in the base dielectric substrate.

In recent years, there has been an impressively fast technological progress in the development of highly efficient lead halide perovskite solar cells. However, the stability of perovskite films and respective solar cells is still an open point of concern and calls for advanced characterization methods. In this work, we identify appropriate measurement conditions for a meaningful analysis of spin-coated absorber-grade perovskite thin films based on methylammonium (MA) lead iodide (MAPbI3) by Raman spectroscopy. The material under investigation and its derivates is the most commonly used for high efficiency devices in the literatures and has yielded working solar cell devices with efficiencies around 10% in our laboratory. We report highly detailed Raman spectra obtained with excitation at 532 nm and 633 nm and their deconvolution taking advantage of the simultaneous fitting of spectra obtained with varying excitation wavelengths. Finally, we propose a fast and contactless methodology...

Improving the sensitivity of existing biosensors for highly sensitive detection of magnetic nanoparticles as biomarkers in biological systems is an important and challenging task. Here, we propose a method of combining the magneto-resistance (MR), magneto-reactance (MX), and magneto-impedance (MI) effects to develop an integrated magnetic biosensor with tunable and enhanced sensitivity. A systematic study of the 7 nm Fe3O4 nanoparticle concentration dependence of MR, MX, and MI ratios of a soft ferromagnetic amorphous ribbon shows that these ratios first increase sharply with increase in particle concentration (0–124 nM) and then remain almost unchanged for higher concentrations (124 nM–1240 nM). The MX-based biosensor shows the highest sensitivity. With this biosensor, ∼2.1 × 1011 7 nm Fe3O4 nanoparticles can be detected over a detection area of 2.0 × 105 μm2, which is comparable to a superconducting quantum interference device biosensor that detects the presence of ∼1 × 108 11 nm ...

A systematic study of the magneto-resistance (MR), magneto-reactance (MX), and magneto-impedance (MI) effects in single and multiple glass-coated amorphous Co 68 B 15 Si 10 Mn 7 microwires is reported. Our studies reveal that the MR, MX, and MI ratios and their corresponding magnetic field sensitivities strongly depend on the number of microwires in an array and on the distance between them. We find that increasing the number of microwires increases the MR and MI ratios and their field sensitivities (g R and g Z , respectively) but decreases the MX ratio and its field sensitivity (g X ). A similar trend is observed for the frequency dependence of these parameters. Increasing the distance between the wires is also found to decrease the MR and MI ratios but increase the MX ratio of the array considerably. From a sensor application perspective, it is interesting to note that for the case of a single microwire, the g X reaches a value as high as 960%/Oe at a frequency of 1 MHz, which is about 192 times of the g R or g Z ($5%/Oe), revealing the possibility of developing ultrahigh sensitivity magnetic field sensors based on the principle of the MX effect.

A magnetoimpedance (MI) biosensor based on Co-based amorphous ribbon was designed and tested to detect functionalized Nanomag-D magnetic beads. While previous studies were focused mainly on exploring the MI change for biosensing, we show that the sensitivity of the biosensor can be enhanced when the change in ac magnetoresistance (MR) or magnetoreactance (MX) is used. The frequency at which the sensitivity of the sensor is optimized can be tuned. This is of potential interest in developing functional biosensors with improved sensitivity and tunable frequency.

Florida -Soft ferromagnetic ribbons with giant magneto-impedance (GMI) effect are attractive candidate materials for high-performance magnetic sensor applications. GMI is a large change in the ac impedance of a ferromagnetic conductor subject to a dc magnetic field. There is a need for further improving GMI response of existing materials, as well as reducing the size of a GMI-based sensor for use in micro-sensing systems. In this work, we report the enhancement of GMI in soft ferromagnetic ribbons (Metglas r 2714A) at high frequencies by reducing the width of the ribbon to the micrometer scale. This finding is of practical importance, as sensors with enhanced field sensitivity and reduced size find wider ranging applications. The origin of the enhanced GMI effect in the microribbon is explained in terms of the skin and demagnetization effects. The relative contributions to the magneto-impedance from the magneto-resistance and magneto-reactance have been analyzed and discussed in detail.

Compounds with photosensitive cinnamoyl groups were synthesized by reac- tion of glycidyl cinnamate with monomeric and polymeric carboxylic acid derivatives . These monomers and polymers were characterized by conven- tional analysis and spectrometry . Upon irradiation in solution the predominant reaction was found to be the trans-cis photoisomerization, while in film the photocrosslinking of cinnernate units occurs.

Single crystal Electron Paramagnetic Resonance (EPR) spectroscopic, X-ray diffraction experiments, and DFT calculations were carried out to determine the crystal structure of zinc creatinine sulfate, to identify the doped Cu(II) binding site, and to investigate the mechanism behind proto-coupled electron transfer observed in UV exposed crystals. Similar to the cadmium-creatinine complex, the metal is not in coordination with the creatininium cation, but forms a hexahydrate which is buffered from the creatininium by an intervening sulfate ion. Both the EPR measured g (2.44, 2.13, 2.08) and copper hyperfine (325, 77, 0 MHz) tensors and structure are consistent with doped copper replacing zinc in the hexahydrate complex. The room temperature EPR tensors are similar to those previously observed for copper hexahydrate in other doped crystal systems, for example in doped Tutton salts, but only those measured at very low temperatures. In these other systems, vibration couplings stemming from dynamic Jahn-Teller effects cause tensor averaging at temperatures up to room temperature. The reasons why this does not happen in the cadmium and current zinc host structure is an area of recent study. Progress towards analyzing and correlating the unpaired Cu(II) and creatininium radical wavefunctions, the crystal structure and the proton-coupled electron transfer will be presented.

Temperature dependent Electron Paramagnetic Resonance (EPR) has long been used to evaluate the dynamic Jahn-Teller behavior of copper ions in doped double metal hexahydrate sulfates (Tutton salts). Our recent EPR analysis of doped cadmium creatininium sulfate has expanded these investigations to include metal-organic Tutton salt analogues. The observed range of measured JT and EPR spectral parameters for the Cu2+(H2O)6 complex in these crystals offers an opportunity to weigh the effect of the host crystal environment on the site dynamics and electronic structure of the copper. To this end, computational chemistry calculations were undertaken for a series of Tutton salts and analogues in order to assess the influence of the host crystalline electric field on the copper unpaired electron wavefunction. DFT computations were performed on clusters centered on the metal-hexaaquo in order determine atomic charges from which electric field vectors and potentials were deduced at points along the copper-water bonds. Our early analysis shows a much higher electric potential in those Tutton systems which exhibit a more pronounced EPR temperature dependency and hence larger JT dynamic behavior. This reflects a stronger coupling to the lattice in these systems. Also, a rough correlation was found between the unpaired electron dx2-y2 orbital spin percentage and the magnitude of the host crystal electric potential. The relationship between the two is being further studied. This work advances our understanding of copper dynamics in biological crystals and how structural and environmental electronic features may facilitate this process.