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World Congress on Biosensors 2014

World Congress on Biosensors 2014
Biosensors 2014

Monday, 31 October 2011

Just Published: Sensors & Actuators A: Physical

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Papers from the latest issue:

High Temperature Dynamic Viscosity Sensor for Engine Oil Applications

28 October 2011, 20:45:52Go to full article
Publication year: 2011
Source: Sensors and Actuators A: Physical, Available online 28 October 2011
Matthew Brouwer, Lokesh A. Gupta, Farshid Sadeghi, Dimitrios Peroulis, Douglas Adams
This paper presents a new high temperature dynamic viscosity sensor for in-situ condition monitoring of engine lubricants. The sensor is used to measure the variation in the quality factor of a vibrating piezoelectric cantilever beam due to viscous damping. The sensor was used to measure the dynamic viscosity of various single and multi-grade engines oils up to 180cP from 25°C to 60°C. The sensor is capable of detecting degradation and dilution of engine oil for both new and used samples of 5 W-30 and 10 W-40 and diluted SAE 30 engine oils. All of the viscosity measurements presented are within 0.13% to 9.8% of the results obtained using the standard Walther equation at various temperatures. An equation relating dynamic viscosity of an oil sample to the quality factor of the beam is presented. The quality factor measurement circuit presented in this research can be implemented in automotive applications for in-situ condition monitoring of lubricant viscosity.

Highlights

► Sensor measures dynamic viscosity of various engine oils at temperatures up to 60°C. ► Maximum measurement range for this specific sensor was 180 cP. ► Capable of detecting degradation and dilution of engine oil in-situ.

Dependency between amplitude and modeshape on vibrating diaphragms

26 October 2011, 20:40:04Go to full article
Publication year: 2011
Source: Sensors and Actuators A: Physical, Available online 25 October 2011
Luis Teia Gomes
Two theories governing the vibration of plates were compared: one, considering the amplitude is independent of modeshape (method of separation of variables) and the other, considering it dependent (Lord Rayleighs’ approach). An exhaustive and thorough study was made, both theoretical for an homogeneous diaphragm and experimentally for several piezoelectric diaphragms, showing that Lord Rayleigh's theory is the correct one and that amplitude of vibration is dependent on modeshape through the coupling factor C. To verify this dependency, several equations were graphically compared showing that accounting for C is critical for a correct prediction. Moreover, the meaning of the coupling factor is explained from a mathematical and physical point of view. The theory predicts correctly both qualitatively and quantitatively the vibration of a diaphragm for varying excitation frequency having only as an input the geometrical and physical properties of the diaphragm.

LPG-based optical fibre sensor for acoustic wave detection

26 October 2011, 20:40:04Go to full article
Publication year: 2011
Source: Sensors and Actuators A: Physical, Available online 25 October 2011
J-O Gaudron, F Surre, T Sun, K.T.V. Grattan
In this work, a long period grating (LPG)-based optical fibre sensor system has been designed and set up, following which it has been evaluated and optimized for acoustic wave detection. The device relies upon the interaction of the acoustic wave with a LPG placed between two pillars (with one being movable) and exposed to a range of representative acoustic waves generated by a loudspeaker placed at a known distance from the sensor thus created. Through determining the response both to the variation of the magnitude and the frequency of the acoustic signals generated by the loudspeaker, the long period grating-based sensor system created has been successfully characterized, showing clear sensitivities to specific acoustic frequencies, irrespective of the signal intensity variations. In addition, these frequencies are found to be closely related to the configuration of the LPG, i.e. the LPG bending curvature created which can be varied, in this laboratory set-up, by changing the distance between the pillars. The experimental results obtained are in good agreement with those obtained from a modified elastic string theory approach, and thus show potential for the use of LPG-based technique for acoustic wave detection in various media,such as fluidsto create a compact and easy to use sensor system.

Enhancing Displacement of Lead-Zirconate-Titanate (PZT) Thin-Film Membrane Microactuators via a Dual Electrode Design

26 October 2011, 20:40:04Go to full article
Publication year: 2011
Source: Sensors and Actuators A: Physical, Available online 25 October 2011
Chuan Luo, G.Z. Cao, I.Y. Shen
A common design of piezoelectric microactuators adopts a membrane structure that consists of a base silicon diaphragm, a layer of bottom electrode, a layer of piezoelectric thin film, and a layer of top electrode. In particular, the piezoelectric thin film is often made of lead-zirconate-titanate (PZT) for its high piezoelectric constants. When driven electrically, the PZT thin film extends or contracts flexing the membrane and generating an out-of-plane displacement. Many manufacturing defects, however, could significantly reduce the designed actuator displacement. Examples include residual stresses, warping, non-uniform etching of the silicon diaphragm, and misalignment between the top electrode and the silicon diaphragm. The purpose of this paper is to develop a dual top-electrode design to enhance the actuator displacement. In this design, the top electrode consists of two disconnected (thus independent) electrode areas, while a continuous bottom electrode serves as the ground. The two top electrodes are located in two regions with opposite curvature when the diaphragm deflects. When the two top electrodes are driven in an out-of-phase manner, the actuator displacement is enhanced. Finite element analyses and experimental measurements both confirm the feasibility of this design. When manufacturing defects are present, experimental results indicate that the actuator displacement can be optimized by adjusting the phase difference between the dual top electrodes.

Application of Silane-Free Atmospheric-Plasma Silicon Deposition to MEMS Devices

26 October 2011, 20:40:04Go to full article
Publication year: 2011
Source: Sensors and Actuators A: Physical, Available online 25 October 2011
Yoshinori Yokoyama, Takaaki Murakami, Shinichi Izuo, Yukihisa Yoshida, Toshihiro Itoh
We have developed a silane-free atmospheric-pressure plasma Si deposition process and investigated the properties of the deposited films by fabricating strain gauge type pressure sensors for the first time. The Si deposition process, which is known as plasma-enhanced chemical transport, utilizes the temperature difference between the solid Si source and the substrate in atmospheric hydrogen plasma. The Si films were deposited at a low temperature of 300 °C at 700 Torr. We have clarified that the Si films were composed of poly crystals by X-ray Diffraction (XRD) patterns and Raman spectra. We fabricated strain gauges using the poly-Si films. The gauge factor of approximately 10 was achieved. The bridge voltage of the pressure sensor was found to be proportional to the pressure. The Si films are deemed appropriate for use as MEMS devices.

Just Published: Sensors & Actuators B: Chemical

Papers from the latest issue:

Application of displacement principle for detecting heavy metal ions and EDTA using microcantilevers

29 October 2011, 21:36:49Go to full article
Publication year: 2011
Source: Sensors and Actuators B: Chemical, Available online 29 October 2011
X. Chen, W. Chen, A. Mulchandani, U. Mohideen
A microcantilever sensor based on a reversible displacement reaction was developed. The demonstration was performed with the Ni-NTA-EDTA sample system. Ni ions, a typical heavy metal, were injected and adsorbed onto a NTA-functionalized AFM cantilever in a fluid cell. This adsorption resulted in tensile stress which was detected by monitoring the corresponding deflection of the microcantilever. In the next step, EDTA was injected into the cell to release the adsorbed Ni ions from the surface of the cantilever. Since EDTA molecules have a stronger affinity for Ni ions compared to NTA, they compete with and eventually replace the NTA molecules and take over the binding positions on Ni. The displacement of Ni ions from the cantilever by EDTA, followed by water flow removes the tensile stress and restores the cantilever deflection to its original value. In this way, both heavy metal ions and EDTA can be specifically recognized. From the cantilever deflection, the concentration of Ni ions and EDTA can be quantified. The detection limits are presently at the micromolar level. Another weaker Ni ion binder, imidazole, was unable to dissociate Ni ions from NTA and produce similar effects. The demonstrated principle can be used for microcantilever sensors which are capable of regeneration for multiple uses. The method presented can be generalized to detect other reactants.

Development of a high sensitive automatic setup for screening of microcystins in surface waters by employing a LED-based photometric detector

29 October 2011, 21:36:49Go to full article
Publication year: 2011
Source: Sensors and Actuators B: Chemical, Available online 29 October 2011
Gláucia P. Vieira, Sheila R.W. Perdigão, Marli F. Fiore, Boaventura F. Reis
In this manuscript, an automatic setup for screening of microcystins in surface waters by employing photometric detection is described. Microcystins are toxins delivered by cyanobacteria within an aquatic environment, which have been considered strongly poisonous for humans. For that reason, the World Health Organization (WHO) has proposed a provisional guideline value for drinking water of 1 μgL. In this work, we developed an automated equipment setup, which allows the screening of water for concentration of microcystins below 0.1 μgL. The photometric method was based on the enzyme-linked immunosorbent assay (ELISA) and the analytical signal was monitored at 458 nm using a homemade LED-based photometer. The proposed system was employed for the detection of microcystins in rivers and lakes waters. Accuracy was assessed by processing samples using a reference method and applying the pairedt-test between results. No significant difference at the 95% confidence level was observed. Other useful features including a linear response ranging from 0.05 up to 2.00 μgL(R = 0.999) and a detection limit of 0.03 μgLmicrocystins were achieved.

Important considerations for effective gas sensors based on metal oxide nanoneedles films

29 October 2011, 21:36:49Go to full article
Publication year: 2011
Source: Sensors and Actuators B: Chemical, Available online 29 October 2011
T. Stoycheva, S. Vallejos, C. Blackman, S.J.A. Moniz, J. Calderer, ...
Gas sensor devices based on either polycrystalline or nanoneedle tungsten oxide were depositedin situon classical ceramic substratesviaAACVD, and subsequently functionalised with gold nanoparticlesviasputtering. The sensing properties of the films were tested to a wide range of analytes, revealing highresponsesto ethanol, hydrogen, and nitrogen dioxide, at low operating temperatures (≤ 250 °C),and a lack of response to carbon monoxide, ammonia, and hydrogen sulfide. In addition, thesensing responsesto hydrogen and nitrogen dioxide, at 100 °C and 150 °C, were improved by using gold functionalised structures. Modest differences of the sensor response magnitude in polycrystalline, and nanoneedle films were observed, suggesting the need of special substrate platforms for effective application of nanostructured films in gas sensors devices.

Single-walled carbon nanotube-magnetite nanoparticles film modified ferrule graphite electrode for voltammetric determination of 2-Diisopropylaminoethanethiol

29 October 2011, 21:36:49Go to full article
Publication year: 2011
Source: Sensors and Actuators B: Chemical, Available online 29 October 2011
S.P. Sharma, M. Farrukh, A. Chaturvedi, A.R. Srivastava, M.V.S. Suryanarayana, ...
An electrochemical sensor based on single-walled carbon nanotube-magnetite nanoparticles (SWCNT-nFe3O4) film for the voltammetric determination of 2-diisopropylaminoethanethiol (DIPAET) is described here. The electrochemical behavior of DIPAET at the SWCNT-nFe3O4film modified ferrule graphite electrode (FGE) was investigated by cyclic voltammetry. DIPAET exhibited enhanced voltammetric response at SWCNT-nFe3O4modified FGE. This electrochemical sensor shows a favorable analytical performance for DIPAET detection with a detection limit (S/N = 1.4) of 1.41 × 10 M, high sensitivity of 53.05 μAnMand electron transfer rate constant of ∼7.22 s. Moreover, DIPAET can be detected in dynamic range of 0.5–4 μg/L with inherent linearity (R = 0.96627)

A Magnetic Resonance Imaging Nanosensor for Hg (II) Based on Thymidine-Functionalized Supermagnetic Iron Oxide Nanoparticles

29 October 2011, 21:36:49Go to full article
Publication year: 2011
Source: Sensors and Actuators B: Chemical, Available online 29 October 2011
Hong Yang, Zhiqing Tian, Juanjuan Wang, Shiping Yang
A MRI nanosensor for Hg (II) was developed based on superparamagnetic iron oxide nanoparticles (SPIO NPs). The detection mechanism is attributed to Hg (II)-induced the nanoassembly of thymidine-functionalized SPIO NPs from a dispersed to an aggregated state with a corresponding decrease in the transverse relaxation time (T2) of adjacent water protons. Furthermore, an enhancement of transverse relaxation rates (1/T2) showed the high selectivity for Hg (II) compared with other transition and main group metal ions.

Characterising Renewable Building Materials

A Model 440 CHN Analyser from Exeter Analytical is being used by the Environmental Research Group (ERG) at the University of East London (www.uel.ac.uk/erg) to help characterise renewable building materials.

With over 23,000 students from 120 countries worldwide, the University of East London (UEL) is located at the heart of Europe's largest regeneration area.  Within the University's Sustainability Research Institute, the Environmental Research Group (ERG) embraces research across a wide range of environmental issues, including peatland, insect and freshwater ecology, botany and ethnobotany, carbon budgeting, nature conservation, environmental quality, sustainability and quality of life.

Stuart Connop, a researcher at the ERG commented "The impetus to investing in a CHN microanalysis system was brought about by the University receiving funding to develop a renewable aggregates test centre for green roof growth aggregates". He added "After reviewing commercially available CHN analysers we selected the Model 440 from Exeter Analytical due to its unique horizontal furnace design which made it ideal for high throughput analysis of our soil, peat, air and water filter sample types".

Paul Hemming, European Sales Manager for Exeter Analytical said "We are very pleased that one of our CHN analysers forms part of the vital ongoing programme of sustainable building research being undertaken by staff at UEL".  He added "With its wide linear range, proprietary combustion technology and horizontal furnace design allowing for removal of residues between runs, the Exeter Analytical Model 440 CHN Analyser is uniquely suited to accurately analysing complex materials such as soils and filtered air and water samples".

As a company dedicated to elemental microanalysis, Exeter Analytical's nearly 30 years of involvement with instruments, consumables and supplies has allowed them to better understand the whole problem facing microanalysts.  As a consequence whether you are a regular or an occasional purchaser - experienced and knowledgeable staff are always available to provide free informed advice.

To receive details of the renewable building materials consultancy service offered by the Environmental Research Group at the University of East London please visit www.uel.ac.uk/erg or contact S.P.Connop@uel.ac.uk.

For further information on the Model 440 CHN Analyser contact Exeter Analytical on tel. +44-2476-323223 (+1-978-251-1411 in North America) or email info@exeteranalytical.co.uk.

Optimised Gene Delivery Solution for Hard-to-Transfect Cells

AMSBIO has introduced GeneIn™ - a new transfection reagent specifically designed to transfect stem cells and primary cells. Comparative studies against other commercially available reagents show GeneIn™ to be superior in transfection efficiency with minimum cytotoxicity.

Delivery of nucleic acids into mammalian cells is often a critical task in the area of cell and molecular biology.  Stem cells and primary cells have traditionally proven to be very difficult to transfect.  GeneIn™ is a novel cationic transfection reagent formulated from proprietary compounds that are chemically defined and are of animal-free origin.  Tested on a wide range of commonly used cell lines and operating over a wide dynamic range, GeneIn™ offers minimal optimization to achieve superior expression results.
GeneIn™ transfection reagent forms part of range of stem cell qualified products including leukemia inhibitory factor (mLIF) and fibroblast feeder cells that offer reproducible performance and high consistency from lot-to-lot.

For further information please visit http://www.amsbio.com/stem-cell-transfection-reagent.aspx or contact AMSBIO on +44-1235-828200 / +1-949-768-8365 or email info@amsbio.com

Friday, 28 October 2011

Just Published: Spectrochimica Acta Part B: Atomic Spectroscopy

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:

Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

15 October 2011, 21:59:56Go to full article
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 15 October 2011
Lei Zhang, Shunsuke Kashiwakura, Kazuaki Wagatsuma
A Boltzmann plot for many iron atomic lines having excitation energies of 3.3 - 6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3 - 4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas.

Highlights

► This paper demonstrates the excitation mechanism on excited energy levels of iron atom having higher excitation energies from a glow discharge plasma, by analyzing a Boltzmann distribution among lots of Fe I lines, which suggests an excitation scheme on the overpopulation of high-lying energy levels of iron atom through Penning-type collisions with argon and neon metastable atoms.

An approach for the mechanism of nickel interferences in hydride generation atomic absorption spectrometric determination of arsenic and antimony

15 October 2011, 21:59:56Go to full article
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 14 October 2011
Emur Henden, Yasemin İşlek, Miray Kavas, Nur Aksuner, Onur Yayayürük, ...
Studies have been carried out to clarify the mechanism of nickel interferences in the hydride generation atomic absorption spectrometric determination of arsenic and antimony. The most serious nickel interferences are observed when nickel/nickel boride nanoparticles are produced during NaBH4reduction. In this study these particles have been observed to have diameters of less than 40 nm and sorb As(III), As(V) and Sb(III) species rather than arsine and stibine generated as so far assumed. Bulk chemical composition and surface structure of these nanoparticals were studied and it was found that if the NaBH4reduction is carried out while passing nitrogen through the solution the black nanoparticles were composed of Ni2B and, if the reduction is carried out under air the black nanoparticles were found to consist of Ni3B or possibly a mixture of Ni(0) and Ni2B. Surface analysis studies with scanning electron microscopy, energy dispersive x-ray spectrometry, x-ray photoelectron spectrometry and x-ray diffraction analysis have shown that the particles have amorphous structure consisting of Ni(0), Ni2B, Ni3B and Ni(OH)2. However, sorption studies have shown that Ni(0) and Ni(OH)2do not sorb the analyte ions and arsine and stibine significantly.

Highlights

► Arsine and stibine are not sorbed by Ni/NixB nanoparticles ► Ni/NixB nanoparticles sorb As(III), As(V) and Sb(III) ions ► Ni interference in HGAAS is due to the sorption of the analyte ions by Ni/NixB

An approach for the mechanism of nickel interferences in hydride generation atomic absorption spectrometric determination of arsenic and antimony

14 October 2011, 22:00:51Go to full article
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 14 October 2011
Emur Henden, Yasemin İşlek, Miray Kavas, Nur Aksuner, Onur Yayayürük, ...
Studies have been carried out to clarify the mechanism of nickel interferences in the hydride generation atomic absorption spectrometric determination of arsenic and antimony. The most serious nickel interferences are observed when nickel/nickel boride nanoparticles are produced during NaBH4reduction. In this study these particles have been observed to have diameters of less than 40 nm and sorb As(III), As(V) and Sb(III) species rather than arsine and stibine generated as so far assumed. Bulk chemical composition and surface structure of these nanoparticals were studied and it was found that if the NaBH4reduction is carried out while passing nitrogen through the solution the black nanoparticles were composed of Ni2B and, if the reduction is carried out under air the black nanoparticles were found to consist of Ni3B or possibly a mixture of Ni(0) and Ni2B. Surface analysis studies with scanning electron microscopy, energy dispersive x-ray spectrometry, x-ray photoelectron spectrometry and x-ray diffraction analysis have shown that the particles have amorphous structure consisting of Ni(0), Ni2B, Ni3B and Ni(OH)2. However, sorption studies have shown that Ni(0) and Ni(OH)2do not sorb the analyte ions and arsine and stibine significantly.

Highlights

► Arsine and stibine are not sorbed by Ni/NixB nanoparticles ► Ni/NixB nanoparticles sorb As(III), As(V) and Sb(III) ions ► Ni interference in HGAAS is due to the sorption of the analyte ions by Ni/NixB

Just Published: Journal of Pharmaceutical and Biomedical Analysis

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:

Energy decomposition analysis of the metal-imine bond in [(CO)4M-SB] (M = Cr, Mo, W; SB: RHC=N−CH2CH2−N=CHR)

26 October 2011, 21:40:14Go to full article
Publication year: 2011
Source: Journal of Organometallic Chemistry, Available online 25 October 2011
Mehdi Bayat, Sadegh Salehzadeh, Gernot Frenking
The electronic and molecular structures of the metal-Schiff base complexes [(CO)4M-SB] (M: Cr, Mo, W; SB: RHC=N−CH2CH2−N=CHR, R = C6H5, C6F5,Ortho-, Meta- and Para-XC6H4(X = F, Cl, Br,CH3)) have been investigated at the DFT level using the exchange correlation functional BP86. The nature of the TM−Schiff base interactions was analyzed with charge and energy decomposition methods. The octahedral equilibrium geometries have C2vsymmetry. The (CO)4M-SB bond dissociation energies vary little for different substituents R. The calculated values indicate rather strong bonds which exhibit the trend for the different metals M = Mo (De= 59.8 – 65.4 kcal/mol) < Cr (De= 62.3 – 67.8 kcal/mol) < W (De= 69.9 – 75.8 kcal/mol). The energy decomposition analysis suggests that the (CO)4M-SB attractive interactions come mainly from electrostatic attraction which provide ∼60% to ∆Eintwhile ∼40% come from orbital interactions. The latter term arises mainly (∼70%) through (CO)4M←SB σ donation from the nitrogen lone-pair orbitals while a much smaller part (∼20%) comes from (CO)4M→SB π backdonation. The transition metals carry large negative partial charges between -2.3 e for M = Cr and -1.1e for M = W.

image

Highlights

► The (CO)4M-SB bond dissociation energies vary little for different SB ligands. ► The M-SB interactions come mainly from electrostatic attraction ( ∼60% to ∆Eint). ► The transition metals, specially Cr atom, carry large negative partial charges.

Order-disorder phase transition with associated cell-tripling in the (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2charge-transfer complex

26 October 2011, 21:40:14Go to full article
Publication year: 2011
Source: Journal of Organometallic Chemistry, Available online 25 October 2011
Yusuke Funasako, Tomoyuki Mochida, Kenji Yoza
The structural change associated with the first-order phase transition (TC= 155.1 K) in a mixed-stack charge-transfer complex (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was investigated crystallographically. X-ray structure determination at 90 K revealed that the transition is associated with the order-disorder of the C5Me4H ring in octamethylferrocene. In the low temperature phase, tripling of the unit cell occurred, accompanied by a change in spacegroup fromP21/c toP−1, and every third octamethylferrocene molecule twists out of the plane to minimize steric interactions.
The structural change associated with the first-order phase transition (TC= 155.1 K) in a mixed-stack charge-transfer complex (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was investigated crystallographically. X-ray structure determination at 90 K revealed that the transition is associated with the order-disorder of the C5Me4H ring in octamethylferrocene. In the low temperature phase, tripling of the unit cell occurred, accompanied by a change in spacegroup fromP21/c toP−1, and every third octamethylferrocene molecule twists out of the plane to minimize steric interactions.
image

Highlights

► The low temperature structure of (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was determined by crystallography.An order-disorder phase transition was accompanied by ring ordering and cell tripling.A Structural change occurred and was caused by steric interactions between the donors and acceptors.

Efficient Transfer Hydrogenation Reaction Catalyzed by A Dearomatized PNP Ruthenium Pincer Complex Under Base-Free Conditions

24 October 2011, 02:44:44Go to full article
Publication year: 2011
Source: Journal of Organometallic Chemistry, Available online 22 October 2011
Li-Peng He, Tao Chen, Dong-Xu Xue, Mohamed Eddaoudi, Kuo-Wei Huang
A dearomatized complex [RuH(PNP)(CO)] (PNP=N,N'-bis(di-tert-butylphosphino)-2,6-diaminopyridine) (3) was prepared by reaction of the aromatic complex [RuH(Cl)(PNP)(CO)] (2) witht-BuOK in THF. Further treatment of3with formic acid led to the formation of a rearomatized complex (4). These new complexes were fully characterized and the molecular structure of complex4was further confirmed by X-ray crystallography. In complex4, a distorted square-pyramidal geometry around the ruthenium center was observed, with the CO ligandtransto the pyridinic nitrogen atom and the hydride located in the apical position. The dearomatized complex3displays efficient catalytic activity for hydrogen transfer of ketones in isopropanol.
A dearomatized PNP-Ru pincer complex (3) efficiently catalyzes transfer hydrogenation of ketones withi-PrOH via metal-ligand cooperation
image

JEOL Opens New Office in Brasil

A leading supplier of electron microscopes and scientific instrumentation, JEOL USA (Peabody, Mass.) and its parent company JEOL Ltd. (Akishima, Japan) have opened an office in Sao Paulo, Brasil to support its growing installed base there, and have relocated the personnel to a new facility this month. 

JEOL has enjoyed a 40-year history in Brasil, with the past 30 being through its agent, Fugiwara Enterprises I.C., Ltda. As the number of JEOL customers has continued to grow in the region, the company decided to provide direct support through JEOL service engineers, administrative, and sales personnel.

“We are pleased to be able to provide this focused and complete support to our customer base,” said Mr. Hisao Wada, Vice President, JEOL USA and President, JEOL BRASIL Ltda. “We have a long history of working with SEM, TEM, and EPMA users in Brasil and enjoy our relationship with fast-growing industry and academia here.”

JEOL USA, a wholly-owned subsidiary of JEOL, Ltd., was founded in 1962 in Massachusetts. The U.S. office is also headquarters to JEOL de Mexico, which celebrated its 20th anniversary in 2011, and JEOL Canada, which opened in 1994.  In September, JEOL USA entered an agreement with Arquimed, its exclusive agent in Chile.

The new JEOL BRASIL Instrumentos Cientificos Ltda. office is now relocated at Av. Jabaquara, 2958-5oandar-cj.52, 04046-500 Sao Paulo, SP, Brasil (Tel. 55-11-5070-4000).

CHESHIRE B2B AGENCY THE SCOTT PARTNERSHIP ANNOUNCES SECOND ACQUISITION IN TWO MONTHS IN CONTINUED GROWTH STRATEGY

Cheshire based B2B agency The Scott Partnership Ltd (www.scottpr.com) announces the acquisition of Cambridge-based scientific marketing agency Phoenix Marcom Ltd (www.phoenixmarcom.co.uk).  The acquisition sees Phoenix move into the holding company of The Scott Partnership Ltd to operate as a wholly owned stand-alone business. The addition of Phoenix Marcom marks the second acquisition since July 2011 for Scott Partnership Holdings Ltd, as it continues to expand its offering in scientific markets with three strong autonomous brands. 

CEO Kath Darlington explains “Phoenix Marcom is a strong, established business, with a solid record of scientific, full-service marketing in Europe.  The company provides its clients with a broad portfolio of marketing services, and has an impressive customer base.   Our intention is that Phoenix will remain autonomous, servicing its predominantly European clients, retaining its focus in the Cambridge area, via the existing Phoenix team.  The founder of Phoenix Marcom, Paul Carter, will join The Scott Partnership to support our expansion in Europe.  All five companies in Scott Partnership Holdings will now offer PR and marketing services, specializing in healthcare and life sciences markets worldwide.”

“The acquisition fits with our strategy for controlled growth, as we strengthen our footprint both globally and locally.  In Europe, three brands located in the scientific hubs of Manchester and Cambridge now serve clients internationally, while our companies based in Boston, USA and Shanghai, China develop our business in North America and the Far East and provide locally based support for all clients.”

The three brands, led by flagship The Scott Partnership, supported by Kapler and now Phoenix Marcom, are building an untouchable service offering in healthcare and life sciences.

Paul Carter, founder of Phoenix Marcom, is also the UK and Eire delegate for the DECHEMA Society for Chemical Engineering and Biotechnology (DECHEMA is the organiser of ACHEMA, the largest process industry trade show which takes place in Germany on a tri-annual basis).  He will retain this role.

For more information on The Scott Partnership, please call +44 (0)1477 539 539. Alternatively e-mail mailto:pr@scottpr.com or visit http://www.scottpr.com/.

Tuesday, 25 October 2011

Just Published: Journal of Analytical and Applied Pyrolysis

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Journal of Analytical and Applied Pyrolysis
http://rss.sciencedirect.com/publication/science/5247
Selected papers from the latest issue:

Analytical pyrolysis of humic substances from a Latosol (Typic Hapludox) under different land uses in Minas Gerais, Brazil

22 October 2011, 03:00:17Go to full article
Publication year: 2011
Source: Journal of Analytical and Applied Pyrolysis, Available online 20 October 2011
Cristiane Pereira de Assis, José A. González-Pérez, José María de la Rosa, Ivo Jucksch, Eduardo de Sá Mendonça, ...
Humic acid (HA) and fulvic acid (FA) fractions isolated from a Humic Red-yellow Latosol (Typic Hapludox) under different land uses (forest, pasture, coffee) were studied by pyrolysis-gas matography–mass spectrometry (Py-GC/MS). Humic substances were extracted from soxhlet lipid free soil samples and the pyrolysis experiments consisted of a thermal desorption at sub-pyrolysis temperature (280 °C) followed by a flash pyrolysis (600 °C) on the same sample.Thermal desorption of HA and FA released mainly carbohydrate -derived compounds, N-compounds and series of alkanes. In surface samples most lignin- and carbohydrate-derived compounds are found weakly bounded to the HA structure indicating recent lignocellulosic contribution. In deeper dark soil layers the release of carbohydrate- derived moieties and N-compounds could indicate active iosynthesis by soil biota producing secondary biopolymers like chitin. Major compounds released after pyrolysis of HA were phenol and other benzene derivatives, whereas for FA aromatic and polyaromatic, N-containing and furan derivatives prevailed.In terms of land use the soils under pasture, FA became more aromatic and enriched in carbohydrate-derived compounds and the presence ofp-vinylguaiacol in the HA could indicate the contribution of lignin from grasses. In contrast, the coffee culture seems to favor the formation of FA with a more polyaromatic and phenolic structure. Most N-bearing compounds in HA and FA extracted from forest soil samples were released by desorption, indicating comparatively weaker bonds in their structure. This could be explained as a more recent contribution and/or comparatively rapid cycling of these organic substances in natural environments.With respect to the general dynamic of organic matter (OM) in the studied Oxisol, our results are compatible with the occurrence of a high biological activity associated with fast humification processes and the migration of oxidized OM, probably with soil cations as vectors.

Highlights

► Analytical pyrolysis (Py-GC/MS) was used to study humic (HA and FA) fractions isolated from a Latosol (Typic Hapludox) under different land uses (forest, pasture, coffee) ► In soil under pasture, FA was found more aromatic and enriched in carbohydrate-derived compounds. ► The coffee culture seems to favor the formation of FA with a more polyaromatic and phenolic structure ► Most N-bearing compounds were released by desorption, indicating weak bonds with HA and FA and a recent contribution and/or rapid cycling ► The results are compatible with the occurrence of fast humification processes and the migration of oxidized OM with soil cations as vectors

BEHAVIOUR OF SELECTED MAJOR ELEMENTS DURING FIXED-BED GASIFICATION OF SOUTH AFRICAN BITUMINOUS COAL

22 October 2011, 03:00:17Go to full article
Publication year: 2011
Source: Journal of Analytical and Applied Pyrolysis, Available online 20 October 2011
J.R. Bunt, F.B. Waanders, H. Schobert
The Sasol-Lurgi Fixed Bed Dry Bottom gasifier (S-L FBDB) treats a feed coal containing c.a. 30% ash forming minerals, which means that there are complex mineralogical processes occurring simultaneously with each other, and in the gasification reactions, within the reactor. To obtain an understanding of the mineral transformational behaviour, a quenched commercial-scale S-L FBDB gasifier was sampled and characterized mineralogically. Crystalline phases measured by XRD analyses show the ash exiting the reactor contains anorthite, quartz, mullite, cristobalite, diopsite, mayenite, anhydrite, muscovite, hematite, and magnetite, with the non-crystalline proportion in the ash bed c.a. 53%. While many of the reactions in gasification are kinetically controlled, the equilibrium analysis using the Fact-Sage 5.3 modelling program provided a computational approach useful in supporting some, though not all, of the experimentally observed chemical and physical behaviour of elements in gasification. Interpretation of hypothetical model output results was of limited utility, since interstitial/matrix aluminosilicate glasses, which are known to form in practise, cannot be modelled at present because no thermodynamic data is available for these species in the Fact-Sage databases.

Highlights

► We model the mineral transformation in a moving bed gasifier ► We dissect the contents of a quenched commercial-scale gasifier to validate the model ► XRD and XRF analysis results show low volatility of elements: Al, Si, Ti, Ca and Fe in agreement with model predictions.

Characterization of Bio-Oil Recovered as Stage Fractions with Unique Chemical and Physical Properties

22 October 2011, 03:00:17Go to full article
Publication year: 2011
Source: Journal of Analytical and Applied Pyrolysis, Available online 20 October 2011
A.S. Pollard, M.R. Rover, R.C. Brown
Bio-oil from fast pyrolysis of biomass consists of hundreds of compounds with a wide range of molecular weights. These include both volatile and non-volatile compounds and viscous oligomers, which complicates recovery of the liquid product from vapors and aerosols generated during pyrolysis. We have developed a bio-oil recovery system that overcomes the fouling problems that commonly occur in conventional condensers, allowing recovery of stage fractions (SF) of bio-oil with distinctive chemical and physical properties. The concept has been evaluated in an 8 kg/h process development unit (PDU) consisting of a fluidized bed pyrolyzer, hot cyclones, and a series of condensers and electrostatic precipitators (ESPs) that recover five stage fractions. Red oak was pyrolyzed in the PDU and the resulting stage fractions of bio-oil analyzed for moisture, modified acid number (MAN), water insoluble content, solids content, higher heating value (HHV), kinematic viscosity and chemical composition.

Highlights

► A bio-oil recovery system was developed that recovers bio-oil as stage fractions ► The bio-oil stage fractions have distinctive chemical and physical properties ► The first two stages concentrated water soluble sugars and water insoluble “pyrolytic lignin” ► Most of the water and acetic acid traditionally found in bio-oil was driven to the last stage fraction

Preparation and characterization of carbonaceous adsorbents from sewage sludge using a pilot-scale microwave heating equipment

22 October 2011, 03:00:17Go to full article
Publication year: 2011
Source: Journal of Analytical and Applied Pyrolysis, Available online 20 October 2011
Q.H. Lin, H. Cheng, G.Y. Chen
Microwave heating technology is considered as a cost-effective alternative way for preparing activated carbon from organic solid wastes. In this study, a pilot-scale microwave heating apparatus with the processing capacity of 5 kg solid waste was constructed to prepare carbonaceous adsorbents from sewage sludge, and the effects of important microwave processing parameters and chemical activation treatments on the quality and yield of resultant carbonaceous adsorbents were investigated with the aim of technological industrialization. The surface properties and chemical compositions of the carbonaceous adsorbents were characterized using nitrogen adsorption, iodine adsorption, scanning electron microscopy, X-ray fluorescence, and Fourier-transform infrared spectroscopy. The microwave heating process could be clearly classed into three stages, i.e., drying, thermal desorption, and carbonization. The increase of carbonization temperature reduced the contents of oxygen-containing functional groups in sludge-based adsorbents. The optimum carbonization temperature was 600 °C, and a higher carbonization temperature (700 °C) gave rise to a detrimental impact on the quality of sludge-based adsorbents, in terms of specific surface area, total pore volume and iodine value. Activation treatment with KOH, ZnCl2and H3PO4achieved the better development of porous texture. The sludge-based adsorbent prepared via KOH activation at carbonization temperature of 600 °C presented the highest BET surface area of 130.7 m gand the highest total pore volume of 0.13 mL g. However, according to the results of batch adsorption experiment, the sludge-based adsorbents prepared via H3PO4activation acted as the best adsorbent to adsorb Cuand Pbfrom aqueous solutions.

Highlights

► A pilot-scale microwave heating apparatus was constructed to prepare carbonaceous adsorbents from sewage sludge. ► The quality of sludge-based adsorbents can be controlled by activation treatment and carbonization temperature. ► The sludge-based adsorbents prepared via H3PO4activation acted as the best adsorbent to adsorb heavy metal ions. ► It is feasible to industrialize microwave heating process for preparing carbonaceous adsorbent form sewage sludge

Just Published: Talanta

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:

nFeature selection versus feature compression in the building of calibration models from FTIR-spectrophotometry datasets

21 October 2011, 03:12:41Go to full article
Publication year: 2011
Source: Talanta, Available online 20 October 2011
Alexander Vergara, Eduard Llobet
Undoubtedly, FTIR-spectrophotometry has become a standard in chemical industry for monitoring, on-the-fly, the different concentrations of reagents and by-products. However, representing chemical samples by FTIR spectra, which spectra are characterized by hundreds if not thousands of variables, conveys their own set of particular challenges because they necessitate to be analyzed in a high-dimensional feature space, where many of these features are likely to be highly correlated and many others surely affected by noise. Therefore, identifying a subset of features that preserves the classifier/regressor performance seems imperative prior any attempt to build an appropriate pattern recognition method. In this context, we investigate the benefit of utilizing two different dimensionality reduction methods, namely the minimum Redundancy-Maximum Relevance (mRMR) feature selection scheme and a new self-organized map (SOM) based feature compression, coupled to regression methods to quantitatively analyze two-component liquid samples utilizing FTIR spectrophotometry. Since these methods give us the possibility of selecting a small subset of relevant features from FTIR spectra preserving the statistical characteristics of the target variable being analyzed, we claim that expressing the FTIR spectra by these dimensionality-reduced set of features may be beneficial. We demonstrate the utility of these novel feature selection schemes in quantifying the distinct analytes within their binary mixtures utilizing a FTIR-spectrophotometer.

Highlights

► We explore the benefit of dimensionality reduction for FTIR datasets. ► We tested the mRMR and SOM dimensionality reduction methods in a quantification task. ► Increasing information will increase the quality of the data if redundancy is low. ► Increasing information will reduce computational costs if redundancy is low. ► Results showed outstanding improvements in quantification performance.

Thermo-optical determination of vapor pressures of TNT and RDX nanofilms

21 October 2011, 03:12:41Go to full article
Publication year: 2011
Source: Talanta, Available online 20 October 2011
Walid M. Hikal, Jeffrey T. Paden, Brandon L. Weeks
Accurate thermodynamic parameters of thin films of explosives are important for understanding their behavior in the nanometer scale as well as in standoff detection. Using UV-absorbance spectroscopy technique, accurate thermodynamic parameters such as activation energies of sublimation, sublimation rates, and vapor pressures of the explosives cyclotrimethylenetrinitramine (RDX) and 2,4,6-trinitrotoluene (TNT) were determined. The values of these parameters are in excellent agreement with those reported using traditional experiments based on gravimetry. In terms of the Clapeyron equation, the dependence of RDX and TNT vapor pressures on temperature can be described by the relations LnP (Pa) = 39.6-15459/T (K) and LnP (Pa) = 34.9-12058/T (K), respectively. Heats of sublimation of RDX and TNT were also determined to be 128 kJ/mol and 100.2 kJ/mol, respectively.

Highlights

► We report the formation of continuous TNT & RDX nanofilms by spin coating. ► We use UV-absorbance spectroscopy to determine sublimation rates of explosives. ► Accurate vapor pressures of TNT& RDX in the nanometer scale are reported. ► Our reported parameters agree well with the mean value in literature. ► Our results expected to have a high impact on trace explosive detection.

New In-Incubator Cell Culture Stimulation

Cells need exercise, too!
Use this multiplexing, in-incubator, cell culture stimulator to keep your cells in shape by preventing de-differentiation or by encouraging pre-commitment.
The NEW C-Pace EP from Harvard Appartus is a multi-channel stimulator designed for the chronic stimulation of bulk quantities of cells in culture incubators. This pacer emits bipolar stimuli, greatly reducing electrolysis at the electrodes.
Features include:
  • Allows treatment of cells in their native environmental conditions
  • Prevents de-differentiation of adult cardiomyocytes
  • Encourages pre-commitment of Stem Cells toward certain muscle phenotypes
  • Ideal for cardiac tissue engineering
In addition to standard pacing protocols, the EP has flexible pacing protocols for arrhythmia, exercise, and irregular pacing. Advanced TTL triggering allows switching to the next programmed pulse train. Functionality can be generalized (e.g. acute pacing) using the Gate and Aux outputs.
The primary benefit of this system is that it allows the researcher to treat the cells in a manner consistent with their native environment. Like using proper maintenance media and incubation, chronic culture pacing will help induce and/or maintain phenotype over time, a key necessity for utilization in cardiac tissue engineering.
For more information contact:
Stephanie Pazniokas , M.S.
spazniokas@harvardapparatus.com

Monday, 24 October 2011

Just Published: Trends in Analytical Chemistry

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:

Common methods for the chiral determination of amphetamine and related compounds II. Capillary electrophoresis and nuclear magnetic resonance

22 October 2011, 22:12:50Go to full article
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 21 October 2011
Justyna Małgorzata Płotka, Calum Morrison, Marek Biziuk
Amphetamine (AM) group and related ring-substituted substances are generally synthetic compounds, belonging to one of the most heavily abused drug groups in recent years. Some compounds in this class also originate from plants. Analysis of the enantiomers of AM-type compounds and metabolites is extremely important for a number of scientific disciplines. From studies of biological activity or mechanisms through determination of precursor molecules in a criminal investigation all use analytical procedures.This article reviews capillary electrophoresis and nuclear magnetic resonance as among the most common, useful methods for the chiral determination of AMs and AM-derived designer drugs in different matrices, including blood, hair, urine, and medicaments. We took into consideration articles published in the past 15 years. We describe commonly used types of chiral derivatization reagent and chiral stationary phase. Tables summarize basic information about conditions and reference data of each procedure. Other methods (e.g., gas chromatography, liquid chromatography and high-performance liquid chromatography, and thin-layer chromatography were described in Part I [Trends Anal. Chem. 30 (2011) 1139].

Highlights

► CE and NMR are useful techniques for the chiral determination of AM type compounds. ► Indirect or direct methods are used for the successful separation of enantiomers. ► CE enantioseparation offers many advantages even over the chromatographic techniques. ► Enantioseparation using microchip-CE with respect to drug analysis is possible. ► NMR techniques usually are complementary to chromatographic approaches.

Removal of sulfur from a solvent extract

22 October 2011, 22:12:50Go to full article
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 21 October 2011
Agata Mechlińska, Lidia Wolska, Jacek Namieśnik
The presence of sulfur in a solvent extract that is to be analyzed chromatographically impairs and sometimes precludes proper interpretation of the chromatogram, as the sulfur peak masks the peaks of other compounds present in the sample, and sulfur also disrupts the operation of the mass detector. This means that discrepancies in the results can lead to erroneous interpretations and false assessments of environmental risk. For this reason, sulfur should be removed from an extract prior to chromatographic analysis and determined in a separate analytical run using an appropriate procedure.This article presents a critical analysis of known methods for removing elemental sulfur from solvent extracts prior to the final determination step of chemicals in the group comprising polychlorinated biphenyls, polyaromatic hydrocarbons and polybrominated diphenyl ethers.

Highlights

► Critical analysis of known methods of removing elemental sulfur from solvent extracts. ► Elemental sulfur is a serious interferent. ► Sulfur must be removed prior to chromatographic analysis & determined in a separate analytical run. ► Sulfur in extract preludes proper interpretation of the chromatogram & disrupts the operation of a mass detector.

Analytical methods for the quantification of volatile aromatic compounds

20 October 2011, 22:17:31Go to full article
Publication year: 2011
Source: TrAC Trends in Analytical Chemistry, Available online 19 October 2011
Małgorzata Biniecka, Sergio Caroli
The investigation of odorants is not an easy task, which needs to be undertaken in the context of fit-for-purpose quality systems. To date, great attention has been paid to determination of the volatile fractions of odorants, since they are responsible for the attributes of global flavor [i.e. a combination of olfactory (aroma) and gustatory (taste) sensations produced by chemicals]. This kind of determination can be carried out by analytical techniques [e.g., gas chromatography (GC) combined with mass spectrometry and/or olfactometric GC]. Methods complementary to GC analysis are available, allowing assessment of the olfactory impact by an electronic nose (e-nose) or a panel of selected individuals. Also, we consider some innovative analytical techniques to study the effects of odorants in food during consumption.

Highlights

► Identification and quantification of volatile fractions of odorants. ► Global flavour as a combination of olfactory (aroma) and gustatory (taste) sensations. ► Gas-chromatography - mass spectroscopy analysis of odorants. ► Gas-chromatography – Olfactometry analysis of odorants. ► Electronic nose.