bluuebunny/crossref_metadata_2025 huggingface dataset:
Failure Mechanism and Testing of PCB Pad Cratering
Authors: Xie Dongji , Cai Miao , Wu Boyi , Geiger David , Shangguan Dongkai , Martin Ivan
Published: March 2011

Pad cratering of printed circuit board (PCB) is becoming a prevailing issue encountered in the PCB assemblies which is accelerated when switching to leadfree process. These units with pad cratering may not fail during functional test as and raise potential failure in the field. This paper uses both experimental and finite element analysis (FEA) approaches to understand the pad strength and pad stresses. An extensive mechanical test by pin pull tests are performed on PCB materials. Cohesive elements are employed to simulate the bonding at the interfaces of pad, laminate and fibers. The results from FEA show that the laminate cracking can be successfully simulated. The design variables such as traces and solder fillet impact are also critical for pad cratering.
Three-Dimensional (3D) Integration Technology
Authors: Ohba Takayuki
Published: March 2011

Three-dimensional (3D) integration and bumpless TSV (Through-Silicon-Via) technologies beyond post-scaling have been described. Since the extreme scaling is limited by physical and economic sense, 3D will be used concurrently with tow-dimensional legacy process. Because vertical wiring in WOW can be connected directly to the upper and lower substrates by self-alignment, bumps are not necessary when TSV interconnects are used. The low aspect ratio of TSVs allows a higher process margin and throughput in etching and metal filling. Multiple TSVs enable die-to-die connections independently, which improves the total yield in wafer-scale stacking. Stacking at the wafer level drastically increases the processing throughput, and bumpless multi-TSVs provide a yield equivalent to or greater than 2D scaling beyond 22-nm nodes.
Electrical Quality of III-V/Oxide Interfaces: Good Enough for MOSFET Devices
Authors: Brammertz Guy , Alian Alireza , Lin H.C. , Nyns Laura , Sioncke Sonja , Merckling Clement , Wang Wei-E , Caymax Matty , Hoffmann Thomas
Published: March 2011

We will present the defect density at In0.53Ga0.47As and InP interfaces with ALD Al2O3 derived by use of the conductance method and from simulation of low frequency CV-curves. Consequences of the interface state distribution for MOS transistor device operation will be highlighted through 1-dimensional electrostatic simulations. The simulation results will be compared as much as possible to different state-of-the-art transistor results presented in literature.
Low Temperature Bonding with Thin Wafers for 3D Integration
Authors: Matthias Thorsten , Kim Bioh , Kettner Paul , Wimplinger Markus , Lindner Paul
Published: March 2011

The ITRS roadmap for high-density TSV interconnects specifies maximum layer thicknesses of 5-15 µm in 2013 with a sub-micron layer-to-layer alignment accuracy. For 3D chip stacks with multiple layers it is not only necessary to handle and process such thin layers, but later on these thin layers have to be stacked and bonded. When it comes to wafer bonding for high-density TSV integration, most efforts have been given to developing Cu-Cu thermo-compression bonding and direct oxide bonding. Stacking of thin wafers can be performed either after the thin wafer is debonded or while the thin wafer is still bonded onto a carrier wafer. Bonding of the thin wafer while still mounted to the carrier wafer allows comfortable and safe wafer handling, but adds some complexity to the wafer bonding process.
Vertical LED with Diamond-Like Carbon Interface for High-Power Illumination
Authors: Sung James C. , Kan Kevin , Sung Michael
Published: March 2011

Most blue light LED chips are made by growing GaN epitaxy on a sapphire substrate. Because sapphire is an insulator, the two electrodes on a conventional LED die must lie on the same side. To improve upon existing technology, several companies are developing vertical stacked LED designs by coating P-type GaN with a reflector (e.g. Ag) that is soldered (e.g. via Au-Sn) to an electrode as the substrate. These techniques have their limitations. In this report, we introduce a methodology to producing a high-powered LED with a thin-film DLC (diamond like carbon) interface that can effectively bridge the semiconductor GaN and metallic substrate. DLC can not only moderate the thermal mismatch, but also to enhance the heat spreading since DLC has a thermal conductivity (475 W/mC) that is significantly higher than even copper. In addition, the metal substrate of the LED can optionally be replaced by a diamond-metal (Ni or Cu) composite that further minimizes the CTE mismatch and boost heat spreading efficacy. Such a DLC LED design can sustain a high drive current so that reduced number of enhanced dies can be used in place of conventional chips for small form-factor general illumination applications.
Experimental and Modeling on Atomic Layer Deposition Al2O3/n-InAs Metal-Oxide-Semiconductor Capacitors with Various Surface Treatments
Authors: Trinh Hai Dang , Chang Edward Yi , Brammertz Guy , Lu Chung-Yu , Nguyen Hong-Quan , Tran Binh-Tinh
Published: March 2011

Ex-situ sulfide and HCl wet chemical treatments in conjunction with in-situ trimethyl aluminum (TMA) pretreatment were performed before the deposition of Al2O3 on n-InAs surfaces. X-ray photoelectron spectroscopy analyses show a significant reduction of InAs native oxides after different treatments. Capacitance-voltage (C-V) characterization of Al2O3/n-InAs structures shows that the frequency dispersion in accumulation regime is small (<0.75% per decade) and does not seem to be affected significantly by the different surface treatments, whereas the latter improves depletion and inversion behaviors of the nMOS capacitors. The interface trap density profiles extracted from simulation show mainly donor-like interface states inside the InAs bandgap and in the lower part of the conduction band. The donor-like traps inside the InAs bandgap and in the lower part of the conduction band were significantly reduced by using wet chemical plus TMA treatments, in agreement with C-V characteristics.
Effects of Surface Pretreatments on p-GaN/GZO Contact by rf Magnetron Sputter
Authors: Wang Wanjing , Li Xifeng , Zhang Jinsong , Zhang Jianhua
Published: March 2011

The Effects of surface pretreatments of p-GaN using H2SO4, HF, KOH solution on the optical and electrical properties of GZO/p-GaN contacts have been investigated using a rf magnetron sputter deposition. The current-voltage characteristics of GZO/p-GaN contact is slightly improved using KOH solution treatment. Contact barrier of GZO/p-GaN can be considerably reduced on annealing at 530 °C for 15 min in N2 ambient and the ohmic contact is almost achieved for with KOH-treated sample. the light luminance of 86.7 cd/m2 at current of 20 mA is obtained for GZO electrodes of LEDs with KOH pretreatment.
A Phase Change Memory Device Fabrication Technology Using Si2Sb2Te6 for Low Power Consumption Application
Authors: Li Ying , Wan Xudong , Song Zhitang , Xie Joseph , Chenc Bomy , Liu Bo , Wu Guanping , Zhu Nanfei , Zhong Min , Xu Jia , Chen Yifeng
Published: March 2011

The Phase Change Memory (PCM) based on the rapid reversible phase change effect in the chalcogenide film has been regarded as one of the most promising candidates for the next-generation nonvolatile memories. The phase change material of Si2Sb2Te6 was newly proposed for phase change memory application, which has lower power consumption and better endurance than conventional Ge2Sb2Te5 materials. In this article, for the first time, the process technology for the phase change memory cell and array fabricated using SST as phase change material replacing conventional GST is presented. By adopting SST PVD process and confined structure, on a small-scale phase change memory array with CMOS access transistors and addressing circuit, we are able to fabricate and demonstrate its full function with low power. The cell electrical testing results are compared between two kinds of films. We also proved a different phase transition mechanism with SST material.
Electrical Characterization of the MOS (Metal-Oxide-Semiconductor) System: High Mobility Substrates
Authors: Lin Dennis H.C. , Brammertz Guy , Sioncke Sonja , Nyns Laura , Alian Alireza , Wang Wei-E , Heyns Marc , Caymax Matty , Hoffmann Thomas
Published: March 2011

Recent developments on CMOS-driven III-V and Ge MOS (Metal-oxide-semiconductor) technologies provide new opportunities in advancing the performance envelope of MOS device as well as the relevant electrical characterization techniques. Understanding the capacitance-voltage (CV) and conductance voltage (GV) responses of the III-V/Ge MOS devices can lead to better assessments of the oxide-semiconductor material systems and more accurate performance predictions.
Characterization and Optical Properties of CdS Thin Films Grown by Chemical Bath Deposition
Authors: Zhang Weibo , Cheng Shuying
Published: March 2011

CdS thin films were prepared on soda-lime glass (SLG) by the chemical bath deposition technique. An aqueous solution of cadmium salts, ammonium chloride, ammonium hydroxide and thiocarbamide were used in the deposition. The obtained CdS film samples were characterized by techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV−VIS−NIR spectrophotometer. The films are of hexagonal phase with preferred (0 0 2) orientation and the grain size increases with the thickness of the films. The films show good transmittance in the visible region. The band gap of the films is 2.41-2.45 eV and decreases with the increasing the thickness of the films.
Enhancement of Luminance via Blending F8BT with Tetraphenyldiaminobiphenyl-Containing Hole Transport Polymer
Authors: Zhang Qiushu
Published: March 2011

We demonstrated polymer light-emitting diodes (PLEDs) based on poly(9,9'-dioctylfluorene-alt-benzothiadiazole) (F8BT) doped with a nonpolyfluorene tetraphenyldiaminobiphenyl-containing hole transport material, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl) benzidine) (PPB). The devices have a configuration of ITO/PEDOT:PSS/emissive layer/Al. The emissive layers consisted of F8BT blended with PPB at varied weight ratio. The brightness of the blend devices was significantly increased in comparison with pure F8BT. For the 7% PPB blend, the luminance reached 1078 cd/m2 at 47.5 mA (528 mA/cm2), improved by 3 fold. We propose that increased charge carrier injection and transport is responsible for the enhanced electroluminescence (EL) performance. EL spectrum was hardly influenced by blending.
Improvements on the Uniformity of a-Si Solar Thin Films by Using Auxiliary Magnetic Field
Authors: Hu L. C. , Chen Y. P. , Chang Jenq-Yang , Lee J. J. , Chen I-Chen , Li Tomi T.
Published: March 2011

The uniformity of large area thin films deposition is a crucial process as we widely apply electron cyclotron resonance chemical vapor deposition (ECR-CVD) in solar industry. In this work, we installed sub-magnetic (auxiliary) fields for inner and outer coils under ECR-CVD process chamber to improve the deposition uniformity of a-Si solar thin films. Next, we measured the distribution of magnetic field along the central axis of chamber and the diameter of substrate surface. By this approach, we investigated the effect of sub-magnetic field to the uniformity of electron cyclotron resonance a-Si solar thin films deposition. We succeeded in obtaining an excellent deposition uniformity of a-Si solar thin films over 150mm diameter on glass substrates by adjusting the magnetic field distribution from inner and outer magnetic coils. The uniformity is within 10%. Moreover, We obtained optimal conditions for solar cell fabrication between the rapid process deposition rates (>10 Aå/sec) and magnetic parameters.
Properties of Multicrystalline Silicon Wafers Based on UMG Material
Authors: Jiang Tingting , Yu Xuegong , Li Xiaoqiang , Gu Xin , Wang Peng , Yang Deren
Published: March 2011

In this paper, we have studied various properties of UMG silicon wafers by combining four-point probe, microwave photo-conductance decay (μ-PCD), Fourier transform infrared (FTIR) spectroscopy,Inductively coupled plasma-mass spectrometry (ICP-MS) and optical microscopy techniques. The results show that the resistivity and the minority-carrier lifetime of UMG silicon are lower than that of standard multicrystalline material, while the detrimental interstitial iron concentration is larger. The concentration of substitutional carbon, interstitial oxygen and dislocation density are close to that in the standard multi-crystalline silicon. Furthermore, a phosphorous gettering has been used to improve the quality of UMG samples. It is found that phosphorus gettering in UMG silicon can increase the minority carrier lifetime and reduce the interstitial iron concentration. But, the minority-carrier lifetime is still not as high as the conventional/standard silicon counterpart after gettering. These results will help us to better understand the properties of UMG silicon wafer.
Effects of Transverse Magnetic Field on Thermal Fluctuations in the Melt of a Cz-Si Crystal Growth
Authors: Liu Xin , Liu Lijun , Wang Yuan
Published: March 2011

Three dimensional (3D) unsteady computations were carried out to understand the effects of transverse magnetic field (TMF) on thermal fluctuations in the melt of a 300 mm Cz-Si crystal growth. A developed LES program with the dynamic SGS model was employed to predict the melt turbulence with or without TMF. The effects of TMF on statistical behaviors of the melt convection were studied. It was found that the thermal fluctuations in the crystallization zone decreased significantly when the TMF was applied. This indicates that the TMF can suppress the flow instability in the melt of the Cz-Si crystal growth.
On the Impact of Heavy Doping on Grown-In Defects in Czochralski-Grown Silicon
Authors: Zhang Xinpeng , Xu W. , Chen J. , Ma Xiangyang , Yang Deren , Gong L. , Tian D. , Vanhellemont Jan
Published: March 2011

The effects of heavy doping of Si on grown-in void size-density distributions and on Flow Pattern Defect (FPD) and Secco Etch Pit Defect (SEPD) density are discussed. Grown-in defects are studied using Scanning Infra Red Microscopy (SIRM) and Secco etching. Doping with 10^20 Ge atoms cm^-3 has a limited effect on the grown-in void size-density distribution but has a clear effect on the FPD density. The observed lower FPD density is most probably related to a decrease of the multiple void density. Co-doping with 10^20 B atoms cm^-3 leads to strong a suppression of the void density by nearly two orders of magnitude in agreement with the reported strong reduction of Crystal Originated Particle (COP) density in low resistivity p-type Si.
Very High Deposition Rate of a-Si:H Thin Films by ECRCVD
Authors: Chiu H. F. , Chang Y. S. , Wu J. Y. , Li Y. S. , Chang Jenq-Yang , Lee C. C. , Chen I-Chen , Su C. C. , Li Tomi T.
Published: March 2011

For the reduction of the manufacturing cost, a high deposition rate of amorphous silicon (a-Si:H) thin film in fabrication is very important. Thus high plasma density and low process temperature deposition technique is keen to develop. Another issue of a-Si:H thin film uses plasma enhanced CVD which causes plasma damage to the film. We use electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit a-Si:H layers with varying microwave power, magnetic field, and hydrogen dilution. The major advantages of ECRCVD are high deposition rate and remote plasma zone that can avoid surface damage. A high deposition rate more than 2 nm/sec was developed by ECRCVD. Fourier transform infrared spectroscopy (FTIR) is used for measuring the microstructure factor (R*) to interpret the effects of microwave power, magnetic field, and hydrogen dilution.
Proton Transport during Electrodeposition of Cobalt in Chloride Electrolytes
Authors: Kongstein Ole E. , Haarberg Geir Martin , Thonstad Jomar
Published: March 2011

In acid cobalt chloride electrolytes the electrodeposition of cobalt and evolution of hydrogen take place simultaneously. On a rotating platinum disc electrode the current efficiency for cobalt deposition was calculated based on the anodic charge needed for stripping of the cobalt deposits divided by the total cathodic charge. The results showed a decrease in current efficiency with increasing rotation rate. From the partial current density for hydrogen evolution the diffusion coefficient for protons was calculated. The derived diffusion coefficients varied with overpotential and pH, but were always one order of magnitude lower compared to what was expected from literature values. This was attributed to water drag when transporting cobalt ions towards the electrode. The variations in the calculated diffusion coefficients were explained by change in the transfer number when the proton concentration was changed.
Assembly and Embedding of Nanoparticles in a Ni-Matrix
Authors: Wurz Marc C. , Wagner Piotr , Rissing Lutz , Caro Juergen
Published: March 2011

To create a new kind of surface suitable for tribological applications, a monolayer of nanoparticles was deposited on a metal-coated substrate. This was followed by embedding the nanoparticles in a metal matrix. For the deposition, SiO2 nanoparticles were used, succeed by an embedding by Ni electroplating. For the deposition, the SiO2 nanoparticles were attached to the surface using a linker of CO2H and SH. In this experiment, the linker connects the nanoparticles with an Au surface. To obtain an optimal linkage between the surface and nanoparticles, various deposition technologies like dip-coating, spin-coating, and electrophoresis were investigated. Afterwards, the SiO2 nanoparticles were embedded by electroplating. The results have shown that it is possible to create a surface with a defined roughness. Furthermore, the mechanical investigations indicate that the nanoparticles have an influence on the hardness of the developed layer.
(Invited) Active Magnetic Micro and Nano Electro-Mechnical Systems (MNEMS)
Authors: Gatzen Hans H.
Published: March 2011

For active micro and nano electromechanical systems (MEMS/NEMS), electromagnetic actuators excel in robustness, are capable of substantial displacements, and of exerting rather large forces. This paper presents an overview over interesting micro and nano magnetic actuation activities in the range of optical devices, fluidic pump systems, biomedical applications, computer and communication technology devices, as well as X and X-Y actuation systems. Particular emphasis is put on research conducted in this field at the Leibniz Universitaet Hannover in Germany.
Fabrication of MEMS on Printed Circuit Boards
Authors: Cvetkovic Srecko , Wienecke Anja , Rissing Lutz
Published: March 2011

There are many ways to manufacture Micro Electro-mechanical Systems (MEMS). For thin-film fabrication of integrated MEMS parts, several different techniques (like etching and electroplating) are applied. Typically, the whole fabrication of MEMS devices is conducted on a carrier wafer, which is fixed and bonded on a Printed Circuit Board (PCB). This procedure is complex and time-consuming. Also the system integration of the bonded MEMS faces difficulties. To reduce complexity and time, as well as to facilitate its integration, a new processing approach is investigated at the Institute for Micro Production Technology at the Leibniz Universität Hannover. The approach chosen for fabrication of electro-magnetic MEMS devices is the application of PCB as carrier wafer. After preparation of the PCB, the MEMS components can be structured by thin-film technology directly on the PCB using the laminated Cu layer. This fabrication procedure allows integrating the MEMS components into the system from the beginning.
Process Development of an Electroplated Permalloy Layer on Magnetic Magnesium for Gentelligent Products
Authors: Belski Alexander , Wurz Marc C. , Rissing Lutz
Published: March 2011

Magnetic magnesium (Mg) is a new storage medium for gentelligent{trade mark, serif} products and requires a reflective layer on its surface to enable a readout process. The readout process is executed by a magneto-optical method based on the KERR effect. A small rotation of a reflected light plane becomes visible applying a soft magnetic 5 µm thick NiFe81/19 layer on top of the magnetic Mg storage medium which mirrors the magnetization states in the storage material. For the electrodeposition of a NiFe81/19 layer on the magnetic Mg surface, the combination of physical vapor deposition (PVD) and electroplating is applied. The thin NiFe81/19 layer deposited by PVD serves as a protection film on the sample surface to avoid etching during electroplating. The electroplating parameters are investigated and optimized to achieve a required concentration of Fe in the deposited layer.
(Invited) Development on Self-Assembly Technique for Arrangement of Chemically Synthesized FePt Nanoparticles
Authors: Hachisu Takuma , Sugiyama Atsushi , Osaka Tetsuya
Published: March 2011

This paper reviews our study of bit patterned media (BPM) using L10 (face centered tetragonal)-FePt nanoparticles. For the practical use of L10-FePt nanoparticles to BPM, some breakthroughs are required: a highly ordered two-dimensional array of nanoparticles on a substrate, a controlled orientation of the axis of easy magnetization in vertical direction on a substrate. Previously, we reported about the achievement for uniformity FePt nanoparticles by controlling chemical synthesis conditions. Moreover, we confirmed the selective chemical interaction Pt in the surface of FePt nanoparticles and SH group with (3-mercaptopropyl)tri-methoxysilane (MPTMS). This study presented a new hybrid technique combining the selective chemical bonding and a substrate with a geometrical grid in order to control the array of FePt nanoparticles with uniform direction of their magnetization. We succeed in preparing uniform array of nanoparticles on geometrical grid with size of 200 nm square prepared using ultraviolet nanoimprint lithography (UV-NIL).
Highly Sensitive Detection of Organophosphate Insecticides Using Biosensors Based on Genetically Engineered Acetylcholinesterase and Poly(3,4-Ethylenedioxythiophene)
Authors: Sikora Tomasz , Istamboulie Georges , Jubete Elena , Ochoteco Estibalitz , Marty Jean-Louis , Noguer Thierry
Published: March 2011

A poly(3,4-ethylenedioxythiophene) (PEDOT) conducting ink is presented as a new electroactive material to be incorporated in acetylcholinesterase-(AChE-) based screen printed biosensors, acting not only as a conducting template but also as an electrochemical mediator for thiocholine oxidation. Two different strategies have been studied for the chemical synthesis of PEDOT: (a) a classical oxidative polymerisation and (b) a more innovative enzymatic polymerisation, giving a water-soluble PEDOT. The use of this water-soluble conducting polymer as mediator in screen-printed biosensors enables its deposition by printing like the rest of the layers. Highly sensitive acetylcholinesterase-(AChE-) based screen-printed biosensors have been constructed using both classical and enzymatic PEDOT, in combination with genetically modified AChE. These electrodes allow the measurement of thiocholine oxidation at potentials of 100 mV versus Ag/AgCl reference electrode through the mediation of PEDOT. Inhibition of thiocholine production in presence of CPO allow for detection of this pesticide in concentrations as low as 1·10−10 M.
A New Case of Spontaneous Regression of Inflammatory Hepatic Pseudotumor
Authors: Jerraya Hichem , Jarboui Slim , Daghmoura Hassen , Zaouche Abdeljelil
Published: March 2011

Introduction. Inflammatory pseudo-tumors (IPT) of the liver are rare and difficult to diagnose, because mimicking malignant tumors.Aim. We report a case of IPT of the liver wich diagnosis was made on clinical, radiological and evolutif features.Observation. A 15-year-old man had a 4-month history of abdominal pain in the right upper quadrant with fever and cought. Two successives ultrasonographies revealed a hypoechoic lesion occuping the segment VIII with 8 cm of diametre. Physical examination was normal. Laboratory investigation showed normal blood counts, liver function test and tumoral markers. Another ultrasonography was interpretated as normal. Tomodensitometry had showon a 3-cm lesion wich enhanced later after contrast injection. A second tomodensitometry done one mounth later described a 2-cm sub capsular heaptic lesion.Discussion. On routine activiy, pre operative diagnosis of IPT of the liver is difficut, and rarely made with certitude because mimicking a malignant tumor. In our cae report here, the analysis of previous history, of clinical, biological and radiological presentation, had permittes us to pose the diagnosis of PTI of the liver and this despite the absence of histological confirmation by percutaneous biopsy.
Pb(Mg1/3Nb2/3)O3–PbTiO3(PMN-PT) Material for Actuator Applications
Authors: Uršič Hana , Santo Zarnik Marina , Kosec Marija
Published: March 2011

Due to its large piezoelectric and electrostrictive responses to an applied electric field the (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN-PT) solid solution has been widely investigated as a promising material for different actuator applications. This paper discusses some of the recent achievements in the field of PMN-PT piezoelectric and electrostrictive actuators manufactured from PMN-PT single crystals, bulk ceramics, or thick films. The functional properties of PMN-PT materials and some representative examples of the investigated PMN-PT actuator structures and their applications are reported.
Systemically Administered Ligands of Toll-Like Receptor 2, -4, and -9 Induce Distinct Inflammatory Responses in the Murine Lung
Authors: Ehrentraut H. , Meyer R. , Schwederski M. , Ehrentraut S. , Velten M. , Grohé C. , Knuefermann P. , Baumgarten G. , Boehm O.
Published: March 2011

Objective. To determine whether systemically administered TLR ligands differentially modulate pulmonary inflammation.Methods. Equipotent doses of LPS (20 mg/kg), CpG-ODN (1668-thioat 1 nmol/g), or LTA (15 mg/kg) were determined via TNF activity assay. C57BL/6 mice were challenged intraperitoneally. Pulmonary NFκB activation (2 h) and gene expression/activity of key inflammatory mediators (4 h) were monitored.Results. All TLR ligands induced NFκB. LPS increased the expression of TLR2, 6, and the cytokines IL-1αβ, TNF-α, IL-6, and IL-12p35/p40, CpG-ODN raised TLR6, TNF-α, and IL12p40. LTA had no effect. Additionally, LPS increased the chemokines MIP-1α/β, MIP-2, TCA-3, eotaxin, and IP-10, while CpG-ODN and LTA did not. Myeloperoxidase activity was highest after LPS stimulation. MMP1, 3, 8, and 9 were upregulated by LPS, MMP2, 8 by CpG-ODN and MMP2 and 9 by LTA. TIMPs were induced only by LPS. MMP-2/-9 induction correlated with their zymographic activities.Conclusion. Pulmonary susceptibility to systemic inflammation was highest after LPS, intermediate after CpG-ODN, and lowest after LTA challenge.
A New Solution for the Director Relaxation Problem in Twisted Nematic Film Based on Wavelet Analysis
Authors: Kudreyko Aleksey , Migranov Nail
Published: March 2011

The present research considers and explains the application
of the Haar wavelets as basis functions in solution of the propagation of
perturbations in low‐dimensional anisotropic media. The computations
of the relaxation problem in the form of traveling waves have shown that
the present approach possesses several advantages over regular methods.
The Current Concept of T H 17 Cells and Their Expanding Role in Systemic Lupus Erythematosus
Authors: Perry Daniel , Peck Ammon B. , Carcamo Wendy C. , Morel Laurence , Nguyen Cuong Q.
Published: March 2011

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a multifaceted range of symptoms affecting almost every organ system. The prototypical pathology of SLE involves the production of antinuclear antibodies and the deposition of immune complexes in basement membranes throughout the body where they induce inflammatory responses. The genetic and environmental etiologies of this process are being intensively sought, and recently, T
H
17 cells have been implicated in the pathogenesis of SLE. T
H
17 cells are CD4+ memory T cells that behave as both helper and effector cell populations functioning through their signature IL-17 cytokines. Their differentiation is distinct to either the T
H
1 or T
H
2 cell lineage, but strongly influences development of adaptive responses, including autoimmunity. This paper details the biological functions and regulation of T
H
17 cells, followed by an update of their expanding role in SLE.
Spatial Numerical Range of Operators on Weighted Hardy Spaces
Authors: Abdollahi Abdolaziz , Heydari Mohammad Taghi
Published: March 2011

We consider the spatial numerical range of operators on weighted Hardy spaces and give conditions for closedness of numerical range of compact operators. We also prove that the spatial numerical range of finite rank operators on weighted Hardy spaces is star shaped; though, in general, it does not need to be convex.
In Vitro Selection of Cathepsin E-Activity-Enhancing Peptide Aptamers at Neutral pH
Authors: Biyani Madhu , Futakami Masae , Kitamura Koichiro , Kawakubo Tomoyo , Suzuki Miho , Yamamoto Kenji , Nishigaki Koichi
Published: March 2011

The aspartic protease cathepsin E has been shown to induce apoptosis in cancer cells under physiological conditions. Therefore, cathepsin E-activity-enhancing peptides functioning in the physiological pH range are valuable potential cancer therapeutic candidates. Here, we have used a general in vitro selection method (evolutionary rapid panning analysis system (eRAPANSY)), based on inverse substrate-function link (SF-link) selection to successfully identify cathepsin E-activity-enhancing peptide aptamers at neutral pH. A successive enrichment of peptide activators was attained in the course of selection. One such peptide activated cathepsin E up to 260%, had a high affinity (KD; ∼300 nM), and had physiological activity as demonstrated by its apoptosis-inducing reaction in cancerous cells. This method is expected to be widely applicable for the identification of protease-activity-enhancing peptide aptamers.
HIV Sexual and Drug-Use Risk in Drug-Dependent Pregnant Patients in Comprehensive Drug Treatment
Authors: Jones Hendrée E. , Wechsberg Wendee M. , O'Grady Kevin E. , Tuten Michelle
Published: March 2011

This secondary analysis study investigated HIV sexual and drug-use risk in drug-dependent pregnant patients over the first month postrandomization to reinforcement-based treatment (RBT) () or usual care (UC) (). Analysis of primary outcomes had indicated that RBT participants spent significantly longer time in treatment and recovery housing than UC participants. The present study examined the ability of 9 risk markers—age, race, estimated gestational age at treatment entry, lifetime substance abuse treatment episodes, history of prostitution charges, history of serious depression, current heroin injection status, current housing status, and current partner substance use—to predict changes in HIV risks. Sexual risk declined for participant subgroups with prostitution-charge histories and unstable housing. Drug-use risk declined for heroin injectors and nondepressed participants. A relationship was found between number of lifetime drug treatment episodes and sexual and drug-use risk. The role of risk markers in the response of drug-dependent pregnant women to drug treatment require attention.
Functions of MDMX in the Modulation of the p53‐Response
Authors: Lenos Kristiaan , Jochemsen Aart G.
Published: March 2011

The MDM family proteins MDM2 and MDMX are two critical regulators of the p53 tumor suppressor protein. Expression of both proteins is necessary for allowing the embryonal development by keeping the activity of p53 in check. Upon stresses that need to activate p53 to perform its function as guardian of the genome, p53 has to be liberated from these two inhibitors. In this review, we will discuss the various mechanisms by which MDMX protein levels are downregulated upon various types of stress, including posttranslational modifications of the MDMX protein and the regulation of mdmx mRNA expression, including alternative splicing. In addition, the putative function(s) of the described MDMX splice variants, particularly in tumor development, will be discussed. Lastly, in contrast to common belief, we have recently shown the existence of a p53‐MDMX feedback loop, which is important for dampening the p53‐response at later phases after genotoxic stress.
Hopf Bifurcation of a Mathematical Model for Growth of Tumors with an Action of Inhibitor and Two Time Delays
Authors: Shi Bao , Zhang Fangwei , Xu Shihe
Published: March 2011

A mathematical model for growth of tumors with two discrete delays is studied. The delays,
respectively, represent the time taken for cells to undergo mitosis and the time taken for the cell to
modify the rate of cell loss due to apoptosis and kill of cells by the inhibitor. We show the influence
of time delays on the Hopf bifurcation when one of delays is used as a bifurcation parameter.
Impedance-Based Miniaturized Biosensor for Ultrasensitive and Fast Prostate-Specific Antigen Detection
Authors: Chornokur Ganna , Arya Sunil K. , Phelan Catherine , Tanner Richard , Bhansali Shekhar
Published: March 2011

This paper reports the successful fabrication of an impedance-based miniaturized biosensor and its application for ultrasensitive Prostate-Specific Antigen (PSA) detection in standard and real human plasma solution, spiked with different PSA concentrations. The sensor was fabricated using photolithographic techniques, while monoclonal antibodies specific to human PSA were used as primary capture antibodies. Electrochemical impedance spectroscopy (EIS) was employed as a detection technique. The sensor exhibited a detection limit of 1 pg/ml for PSA with minimal nonspecific binding (NSB). This detection limit is an order of magnitude lower than commercial PSA ELISA assays available on the market. The sensor can be easily modified into an array for the detection of other biomolecules of interest, enabling accurate, ultrasensitive, and inexpensive point-of-care sensing technologies.
Metformin Induces Both Caspase-Dependent and Poly(ADP-ribose) Polymerase-Dependent Cell Death in Breast Cancer Cells
Authors: Zhuang Yongxian , Miskimins W. Keith
Published: March 2011

There is substantial evidence that metformin, a drug used to treat type 2 diabetics, is potentially useful as a therapeutic agent for cancer. However, a better understanding of the molecular mechanisms through which metformin promotes cell-cycle arrest and cell death of cancer cells is necessary. It will also be important to understand how the response of tumor cells differs from normal cells and why some tumor cells are resistant to the effects of metformin. We have found that exposure to metformin induces cell death in all but one line, MDA-MB-231, in a panel of breast cancer cell lines. MCF10A nontransformed breast epithelial cells were resistant to the cytotoxic effects of metformin, even after extended exposure to the drug. In sensitive lines, cell death was mediated by both apoptosis and a caspase-independent mechanism. The caspase-independent pathway involves activation of poly(ADP-ribose) polymerase (PARP) and correlates with enhanced synthesis of PARP and nuclear translocation of apoptosis-inducing factor (AIF), which plays an important role in mediating cell death. Metformin-induced, PARP-dependent cell death is associated with a striking enlargement of mitochondria. Mitochondrial enlargement was observed in all sensitive breast cancer cell lines but not in nontransformed cells or resistant MDA-MB-231. Mitochondrial enlargement was prevented by inhibiting PARP activity or expression. A caspase inhibitor blocked metformin-induced apoptosis but did not affect PARP-dependent cell death or mitochondrial enlargement. Thus, metformin has cytotoxic effects on breast cancer cells through 2 independent pathways. These findings will be pertinent to efforts directed at using metformin or related compounds for cancer therapy. Mol Cancer Res; 9(5); 603–15. ©2011 AACR.
Quetiapine, Olanzapine and Haloperidol Affect Human Plasma Lipid Peroxidation in vitro
Authors: Dietrich-Muszalska Anna , Kontek Bogdan , Rabe-Jabłońska Jolanta
Published: March 2011

Objective: Oxidative injury in schizophrenia may be caused not only by pathophysiological processes but partly also by treatment with antipsychotics. The purpose of the present study was to examine and to compare the effects of quetiapine (QUE), olanzapine (OLA) and haloperidol (HAL), at final concentrations corresponding to doses used for treatment of acute episodes of schizophrenia, on plasma lipid peroxidation in vitro, measured by the level of thiobarbituric acid-reactive substances (TBARS). Methods: Blood from 30 healthy volunteers was collected into ACD (citric acid/citrate/dextrose) solution. The drugs in form of active substances were dissolved in 0.01% dimethyl sulfoxide, added to plasma at the final concentrations [QUE (175 and 275 ng/ml), OLA (20 and 40 ng/ml), HAL (4 and 20 ng/ml)] and incubated for 1 and 24 h at 37°C. The level of TBARS was measured spectrophotometrically (according to the Rice-Evans method, 1991). Results: The comparative study in vitro showed that QUE causes a decrease in the TBARS level in plasma, whereas HAL increases the plasma TBARS level. After 24 h of incubation of plasma with QUE or HAL (at lower and higher concentrations),thedifferences in TBARS levels between the drugs were significant (p = 5.9 × 10–4, p = 2.2 × 10–5, respectively). Conclusion: QUE and OLA, contrary to the prooxidative action of HAL, did not induce oxidative stress; moreover, QUE has antioxidant properties.
Supplementation with Eicosapentaenoic Omega-3 Fatty Acid Does Not Influence Serum Brain-Derived Neurotrophic Factor in Diabetes Mellitus Patients with Major Depression: A Randomized Controlled Pilot Study
Authors: Bot Mariska , Pouwer François , Assies Johanna , Jansen Eugène H.J.M. , Beekman Aartjan T.F. , de Jonge Peter
Published: March 2011

Background: Low brain-derived neurotrophic factor (BDNF) levels are observed in both depressed and diabetes patients. Animal research has shown that omega-3 polyunsaturated fatty acids increase BDNF levels. In this exploratory randomized double-blind placebo-controlled study in diabetes patients with major depression, we tested whether (a) omega- 3 ethyl-eicosapentaenoic acid (E-EPA) leads to increased serum BDNF levels and (b) whether changes in BDNF levels are associated with corresponding changes in depression. Methods: Patients received 1 g/day E-EPA (n = 13) or placebo (n = 12) for 12 weeks, in addition to ongoing antidepressant therapy. At baseline and 12-week follow-up, we determined serum BDNF levels and depression severity, using the Montgomery-Åsberg Depression Rating Scale. Results: We found no effect of E-EPA on BDNF levels (t = –0.144, p = 0.887), and changes in BDNF levels and depression severity were not significantly associated (Spearman’s ρ = –0.115, p = 0.593). Conclusion: Our study does not provide evidence that supplementation with E-EPA improves BDNF levels in depressed diabetes patients already using antidepressants.
Mechanisms of Whole Chromosome Gains in Tumors – Many Answers to a Simple Question
Authors: Gisselsson D.
Published: March 2011

Whole chromosome gain is the most common type of gross genomic abnormality observed in human tumors. It is particularly frequent in lympho-haematopoietic and embryonic neoplasms, where trisomies and tetrasomies are typically present together with few or no other cytogenetic imbalances, resulting in hyperdiploid chromosome numbers. Despite the high prevalence of whole chromosome gains in neoplastic cells, their mechanism of origin remains disputed. Here, 4 potential models for the generation of whole chromosome gains are reviewed: (1) loss of chromosomes from the tetraploid level, (2) sequential sister chromatid non-disjunction, (3) multipolar mitosis coupled to sister chromatid non-disjunction, and (4) multipolar mitosis coupled to incomplete cytokinesis. Each of these mechanisms may in theory result in the generation of hyperdiploid neoplastic clones, but none of them were single-handedly able to reproduce the scenario of chromosome copy number alterations in tumors when cell populations resulting from these models were simulated in silico and compared to published cytogenetic data. To develop models for the generation of whole chromosome gains further, it is critical to improve our knowledge of the principles of clonal selection in tumors and of the baseline rate of chromosome segregation errors in human cells. To illustrate this, a model combining multipolar mitosis coupled to incomplete cytokinesis with a low rate of baseline sister chromatid non-disjunction was shown readily to reproduce copy number distributions in hyperdiploid karyotypes from human tumors.
Is There a Paternal Age Effect for Aneuploidy?
Authors: Fonseka K.G.L. , Griffin D.K.
Published: March 2011

Finding a positive association between paternal age and the incidence of aneuploidy is not difficult. A cursory analysis however reveals that any association is indirect, brought about by a close correlation between paternal age and maternal age. Approaches for dissecting out the confounding age effects of the mother has led to a lively exchange among epidemiologists, with perhaps a consensus for the absence of a paternal age effect, at least for trisomy 21. Molecular studies revealed the relatively minor contribution of paternal errors to trisomy, but even research on the paternally derived trisomies alone has been inconclusive; thus studies focussed directly on the sperm heads. Human-hamster fusion assays were superseded by FISH for establishing any possible link between age and the proportion of disomic sperm in an ejaculate. Despite innumerable microscope hours however, although convincing studies suggesting an age effect for disomies 1, 9, 18 and 21 and the sex chromosomes are in the literature, others failed to notice any association for these or other chromosomes. It is biologically plausible that chromosomal non-disjunction errors should increase with age. Male reproductive hormone production, testicular morphology and semen parameters all decline slowly with age and paternal age is implicated in congenital birth defects, such as achondroplasia and Apert syndromes and also linked to compromised DNA repair mechanisms. Despite several decades of epidemiological and molecular cytogenetic studies, however, we are still not close to a definitive answer of whether or not there is a paternal age effect for aneuploidy. In this review we conclude by questioning the efficacy of FISH because of difficulties in detecting nullisomy and because of evidence that the centromeres (from which most sperm-FISH probes are derived) cluster at the nuclear centre. Array-based approaches may well supersede FISH in addressing the question of a paternal age effect; for now, however, the jury is still out.
Environmental Hazard in the Aetiology of Somatic and Germ Cell Aneuploidy
Authors: Pacchierotti F. , Eichenlaub-Ritter U.
Published: March 2011

Sources of environmental exposures to potentially aneugenic agents are many and include occupational and therapeutic exposures, and exposures associated with lifestyle habits. In this present study, some of these agents and exposure scenarios are discussed that involve potentially large population targets and/or seem to affect chromosome segregation by previously unsuspected mechanisms: metals, possibly acting by epigenetic mechanisms; nano-sized particles that might directly interact with subcellular components of the mitotic and meiotic machineries; cytostatic drugs in healthcare occupations; anticancer therapies potentially affecting the genetic integrity of gametes; continuously increasing electromagnetic field exposures with some sparse evidence of aneugenic activity; endocrine disruptors and their seemingly elusive effects in mouse oocytes, including the first evidence that prenatal exposure could affect meiotic nondisjunction in adult life. Hazards are considered for both somatic cells at risk of neoplastic transformation or tumour progression by chromosome loss and gain and germ cells at risk of heritable aneuploidies associated with spontaneous abortions or genetic diseases. Finally, possible synergistic interactions between environmental exposure and ageing or genetic predisposition are considered that could influence ultimate risks.
Aneuploidy in the Human Blastocyst
Authors: Fragouli E. , Wells D.
Published: March 2011

Studies of human cleavage stage embryos, 3 days after fertilization of the oocyte, have revealed remarkably high levels of chromosome abnormality. In addition to meiotic errors derived from the gametes, principally the oocyte, mitotic errors occurring after fertilization are also common, leading to widespread chromosomal mosaicism. The prevalence of chromosome anomalies in embryos may explain the relatively poor fertility and fecundity in humans and the low success rates of assisted reproductive treatments (e.g., IVF). While much is known concerning the incidence of aneuploidy during the first 3 days following fertilization, it is only in the last couple of years that large numbers of embryos at the final stage of preimplantation development, the blastocyst stage, 5 days after fertilization, have been subjected to detailed analysis. Here we discuss the latest data from the comprehensive cytogenetic analysis of blastocysts. These findings indicate that the majority of selection against chromosome abnormalities does not occur until the time of implantation or shortly after, with aneuploidy typically affecting more than 50% of blastocysts. Additionally, clinical results presented suggest that screening of blastocyst stage embryos for chromosome abnormality, with preferential transfer to the uterus of those found to be euploid, may help to improve the success rates of assisted reproductive treatments.
Sister Chromatid Cohesion Control and Aneuploidy
Authors: Barbero J.L.
Published: March 2011

Apart from a personal tragedy, could Down syndrome, cancer and infertility possibly have something in common? Are there links between a syndrome with physical and mental problems, a tumor growing out of control and the incapability to reproduce? These questions can be answered if we look at the biological functions of a protein complex, named cohesin, which is the main protagonist in the regulation of sister chromatid cohesion during chromosome segregation in cell division. The establishment, maintenance and removal of sister chromatid cohesion is one of the most fascinating and dangerous processes in the life of a cell. Errors in the control of sister chromatid cohesion frequently lead to cell death or aneuploidy. Recent results showed that cohesins also have important functions in non-dividing cells, revealing new, unexplored roles for these proteins in human syndromes, currently known as cohesinopathies. In the last 10 years, we have improved our understanding of the molecular mechanisms of the cohesin and cohesin-interacting proteins regulating the different events of sister chromatid cohesion during cell division in mitosis and meiosis.