bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of a New Human Adenovirus Protein Encoded by a Novel Late
l
-Strand Transcription Unit
Authors: Tollefson Ann E. , Ying Baoling , Doronin Konstantin , Sidor Peter D. , Wold William S. M.
Published: September 2007

A short open reading frame named the “U exon,” located on the adenovirus (Ad)
l
-strand (for leftward transcription) between the early E3 region and the
fiber
gene, is conserved in mastadenoviruses. We have observed that Ad5 mutants with large deletions in E3 that infringe on the U exon display a mild growth defect, as well as an aberrant Ad E2 DNA-binding protein (DBP) intranuclear localization pattern and an apparent failure to organize replication centers during late infection. Mutants in which the U exon DNA is reconstructed have a reversed phenotype. Chow et al. (L. T. Chow et al., J. Mol. Biol. 134:265-303, 1979) described mRNAs initiating in the region of the U exon and spliced to downstream sequences in the late DBP mRNA leader and the DBP-coding region. We have cloned this mRNA (as cDNA) from Ad5 late mRNA; the predicted protein is 217 amino acids, initiating in the U exon and continuing in frame in the DBP leader and in the DBP-coding region but in a different reading frame from DBP. Polyclonal and monoclonal antibodies generated against the predicted U exon protein (UXP) showed that UXP is ∼24K in size by immunoblot and is a late protein. At 18 to 24 h postinfection, UXP is strongly associated with nucleoli and is found throughout the nucleus; later, UXP is associated with the periphery of replication centers, suggesting a function relevant to Ad DNA replication or RNA transcription. UXP is expressed by all four species C Ads. When expressed in transient transfections, UXP complements the aberrant DBP localization pattern of UXP-negative Ad5 mutants. Our data indicate that UXP is a previously unrecognized protein derived from a novel late
l
-strand transcription unit.
Identification and Functional Analysis of Salmon Annexin 1 Induced by a Virus Infection in a Fish Cell Line
Authors: Hwang Hyun Jin , Moon Chang Hoon , Kim Han Geun , Kim Joo Yun , Lee Jung Min , Park Jeong Woo , Chung Dae Kyun
Published: September 2007

In this study, we investigated changes in protein expression of fish cells induced by infection of infectious pancreatic necrosis virus (IPNV) using two-dimensional electrophoresis and matrix-assisted laser desorption-time of flight proton motive force analysis and identified a novel type of salmon annexin 1 that is induced in fish cells by infection with IPNV. Northern blotting showed that this annexin is overexpressed in IPNV-infected cells compared to control cells, and further analysis revealed that it has a 1,509-bp full-length cDNA sequence with an open reading frame encoding 339 amino acids (GenBank accession no. AY944135). Amino acid sequence analysis revealed that this protein belongs to the annexin 1 subfamily. By applying RNA interference, the mRNA levels of salmon annexin 1 were suppressed and, under these conditions, apoptosis of IPNV-infected cells was significantly increased. While small interfering RNA (siRNA) treatment did not affect the levels of the viral proteins significantly until 10 h postinfection, it reduced the titer of extracellular virus to 25% of that of a scrambled siRNA-treated control. These data provide evidence of an antiapoptotic function for salmon annexin 1 that is important for IPNV growth in cultured cells.
Occupational risks for adenocarcinoma of the nasal cavity and paranasal sinuses in the German wood industry
Authors: Pesch B , Pierl C B , Gebel M , Gross I , Becker D , Johnen G , Rihs H-P , Donhuijsen K , Lepentsiotis V , Meier M , Schulze J , Brüning T
Published: September 2007

Objectives:

To examine the risk of wood dust and chemical exposures for adenocarcinoma of the nasal cavity and paranasal sinuses (ADCN) among German wood workers.

Methods:

An industry-based case-control study with 86 male ADCN cases and 204 controls was conducted in the German wood-working industries. Cumulative and average wood-dust exposure was quantified with a job-exposure matrix based on wood-dust measurements at recent and historical workplaces. Probabilities of exposure to wood preservatives, stains, varnishes, and formaldehyde were semi-quantitatively rated. Odds ratios and 95% confidence intervals were calculated with logistic regression analysis conditional on age and adjusted for smoking and other factors. For estimating the risks of either wood dust or chemical additives, the authors additionally adjusted for the corresponding co-exposure.

Results:

ADCN occurred relatively more frequently among wood workers that had ever worked as cabinet makers or joiners (OR 2.96, 95% CI 1.46 to 6.01) than as saw millers (OR 0.15, 95% CI 0.03 to 0.68). Average exposure to inhalable wood dust ⩾5 mg/m3was associated with a high risk (OR 48.47, 95% CI 13.30 to 176.63) compared to levels below 3.5 mg/m3. Assuming 40 years of exposure under these concentrations, the corresponding OR was 4.20 (95% CI 1.69 to 10.43). Exposure between 3.5 and 5 mg/m3was also found to pose a risk (OR 10.54, 95% CI 3.34 to 33.27). Exposure to pigment stains before 1970 was associated with an increased risk (OR 3.03; 95% CI 1.11 to 8.26). No significant associations were estimated for wood preservatives, varnishes, and formaldehyde.

Conclusions:

The authors found an elevated ADCN risk for exposure to inhalable wood dust above 3.5 mg/m3. The rareness of the disease does not allow the exclusion of risk below that concentration. For pigment stains, there is evidence for an association of historical exposure with the development of ADCN in German wood workers.
INVOLUTIVELY BORDERED WORDS
Authors: KARI LILA , MAHALINGAM KALPANA
Published: September 2007

In this paper we study a generalization of the classical notions of bordered and unbordered words, motivated by DNA computing. DNA strands can be viewed as finite strings over the alphabet {A, G, C, T}, and are used in DNA computing to encode information. Due to the fact that A is Watson-Crick complementary to T and G to C, DNA single strands that are Watson-Crick complementary can bind to each other or to themselves in either intended or unintended ways. One of the structures that is usually undesirable for biocomputation, since it makes the affected DNA string unavailable for future interactions, is the hairpin: If some subsequences of a DNA single string are complementary to each other, the string will bind to itself forming a hairpin-like structure. This paper studies a mathematical formalization of a particular case of hairpins, the Watson-Crick bordered words. A Watson-Crick bordered word is a word with the property that it has a prefix that is Watson-Crick complementary to its suffix. More generally, we investigate the notion of θ-bordered words, where θ is a morphic or antimorphic involution. We show that the set of all θ-bordered words is regular, when θ is an antimorphic involution and the set of all θ-bordered words is context-sensitive when θ is a morphic involution. We study the properties of θ-bordered and θ-unbordered words and also the relation between θ-bordered and θ-unbordered words and certain type of involution codes.
PARALLELISM IN QUANTUM INFORMATION PROCESSING DEFEATS THE UNIVERSAL COMPUTER
Authors: NAGY MARIUS , AKL SELIM G.
Published: September 2007

This paper is structured around the idea that a finite Universal Computer cannot be realized and presents in detail a series of unconventional computing paradigms supporting this idea from a quantum mechanical perspective.
EMBODIED COMPUTATION
Authors: HAMANN HEIKO , WÖRN HEINZ
Published: September 2007

The traditional computational devices and models, such as the von Neumann architecture or the Turing machine, are strongly influenced by concepts of central control and perfection. The standard models of computation seem to cover the reality of computation only partially and lack, in particular, in the ability to describe more natural forms of computation. In this paper we propose the concept of embodied computation, a straight forward advancement of well known concepts such as amorphous computing, emergent phenomena and embodied cognitive science. Many embodied microscopic computational devices form a single macroscopic device of embodied computation. The solution to computational problems emerges from a huge amount of local interactions. The system's memory is the sum of the positional information and possibly of the internal states. Such systems are very robust and allow different methodologies to analyze computation. To back this theoretic concept some results based on simulations are given and potential benefits of this approach are discussed.
AUTHENTICATED QUANTUM KEY DISTRIBUTION WITHOUT CLASSICAL COMMUNICATION
Authors: NAGY NAYA , AKL SELIM G.
Published: September 2007

The aim of quantum key distribution protocols is to establish a secret key among two parties with high security confidence. Such algorithms generally require a quantum channel and an authenticated classical channel. This paper presents a totally new perception of communication in such protocols. The quantum communication alone satisfies all needs of array communication between the two parties. Even so, the quantum communication channel does not need to be protected or authenticated whatsoever. As such, our algorithm is a purely quantum key distribution algorithm. The only certain identification of the two parties is through public keys.
DARBOUX TRANSFORMATION AND SOLITON SOLUTIONS FOR GENERALIZED WKI EQUATIONS
Authors: XU RUI
Published: September 2007

In this paper, a systematic method is presented to construct the Darboux transformation for generalized WKI equations. With the aid of symbolic computation, new soliton-like solutions for the GWKI equations are obtained by using its Darboux transformation.
TYPICAL BLOCKS OF THE CATEGORY $\mathcal{O}$ FOR THE QUEER LIE SUPERALGEBRA
Authors: FRISK ANDERS
Published: September 2007

We study the category [Formula: see text] for the queer Lie superalgebra 𝔮(n), and the corresponding block decomposition induced by infinitesimal central characters. In particular, we show that the so-called typical blocks correspond to standardly stratified algebras, in the sense of Cline, Parshall and Scott. By standard arguments for Lie algebras, modified to the superalgebra situation, we prove that these CPS-stratified algebras have finite finitistic dimension and the double centralizer property. Moreover, we prove that certain strongly typical blocks are equivalent. Finally, we generalize Kostant's Theorem to the 𝔮(n)-case and describe all typical 𝔮(2)-blocks.
QUASI-MORPHIC RINGS
Authors: CAMILLO V. , NICHOLSON W. K.
Published: September 2007

A ring R is called left morphic if R/Ra ≅ l (a) for each a ∈ R, equivalently if there exists b ∈ R such that Ra = l (b) and l (a) = Rb. In this paper, we ask only that b and c exist such that Ra = l (b) and l (a) = Rc, and call R left quasi-morphic if this happens for every element a of R. This class of rings contains the regular rings and the left morphic rings, and it is shown that finite intersections of principal left ideals in such a ring are again principal. It is further proved that if R is quasi-morphic (left and right), then R is a Bézout ring and has the ACC on principal left ideals if and only if it is an artinian principal ideal ring.
NONCOMMUTATIVE SYMMETRIC FUNCTIONS AND W-POLYNOMIALS
Authors: DELENCLOS JONATHAN , LEROY ANDRÉ
Published: September 2007

Let K, S, D be a division ring, an endomorphism and a S-derivation of K, respectively. In this setting we introduce generalized noncommutative symmetric functions and obtain Viète formula and decompositions of differential operators. W-polynomials show up naturally, their connections with P-independency, Vandermonde and Wronskian matrices are briefly studied. The different linear factorizations of W-polynomials are analyzed. Connections between the existence of LLCM of monic linear polynomials with coefficients in a ring and the left duo property are established at the end of the paper.
MAXIMAL NON-UNIVERSALLY CATENARIAN SUBRINGS OF A FIELD: THE NON-INTEGRALLY CLOSED CASE
Authors: BEN NASR MABROUK
Published: September 2007

In this paper, we deal with the study of maximal non-universally catenarian subrings (that is a non-universally catenarian subring R of a domain S such that any subring of S that properly contains R is universally catenarian). Several satisfactory results are given, and for S a field and R not integrally closed, we characterize these domains.
ON MAXIMAL NON-ACCP SUBRINGS
Authors: AYACHE AHMED , DOBBS DAVID E. , ECHI OTHMAN
Published: September 2007

A domain R is a maximal non-ACCP subring of its quotient field if and only if R is either a two-dimensional valuation domain with a DVR overring or a one-dimensional nondiscrete valuation domain. If R ⊂ S is a minimal ring extension and S is a domain, then (R,S) is a residually algebraic pair. If S is a domain but not a field, a maximal non-ACCP subring extension R ⊂ S is a minimal ring extension if (R,S) is a residually algebraic pair and R is quasilocal. Results with a similar flavor are given for domains R ⊂ S sharing a nonzero ideal, with applications to rings R of the form A + XB[X] or A + XB[[X]]. If R ⊂ S is a minimal ring extension such that R is a domain and S is not (R-algebra isomorphic to) an overring of R, then R satisfies ACCP if and only if S satisfies ACCP.
The Pathophysiology of Fragile X Syndrome
Authors: Penagarikano Olga , Mulle Jennifer G. , Warren Stephen T.
Published: September 2007

Fragile X syndrome is the most common form of inherited mental retardation. The disorder is mainly caused by the expansion of the trinucleotide sequence CGG located in the 5′ UTR of the FMR1 gene on the X chromosome. The abnormal expansion of this triplet leads to hypermethylation and consequent silencing of the FMR1 gene. Thus, the absence of the encoded protein (FMRP) is the basis for the phenotype. FMRP is a selective RNA-binding protein that associates with polyribosomes and acts as a negative regulator of translation. FMRP appears to play an important role in synaptic plasticity by regulating the synthesis of proteins encoded by certain mRNAs localized in the dendrite. An advancing understanding of the pathophysiology of this disorder has led to promising strategies for pharmacologic interventions.
The Genetic Lexicon of Dyslexia
Authors: Paracchini Silvia , Scerri Thomas , Monaco Anthony P.
Published: September 2007

Reading abilities are acquired only through specific teaching and training. A significant proportion of children fail to achieve these skills despite normal intellectual abilities and an appropriate opportunity to learn. Difficulty in learning to read is attributable to specific dysfunctions of the brain, which so far remain poorly understood. However, it is recognized that the neurological basis for dyslexia, or reading disability, is caused in large part by genetic factors. Linkage studies have successfully identified several regions of the human genome that are likely to harbor susceptibility genes for dyslexia. In the past few years there have been exciting advances with the identification of four candidate genes located within three of these linked chromosome regions: DYX1C1 on chromosome 15, ROBO1 on chromosome 3, and KIAA0319 and DCDC2 on chromosome 6. Functional studies of these genes are offering new insights about the biological mechanisms underlying the development of dyslexia and, in general, of cognition.
microRNAs in Vertebrate Physiology and Human Disease
Authors: Chang Tsung-Cheng , Mendell Joshua T.
Published: September 2007

Over the past five years, the importance of a diverse class of 18–24 nucleotide RNA molecules, known as microRNAs (miRNAs) has increasingly been recognized. These highly conserved RNAs regulate the stability and translational efficiency of complementary target messenger RNAs. The human genome is now predicted to encode nearly 1,000 miRNAs that likely regulate at least one third of all human transcripts. Despite rapid progress in miRNA discovery, the physiologic functions of only a small number have been definitively established. In this review, we discuss the principles of miRNA function that have emerged from the studies performed thus far in vertebrates. We also discuss known and potential roles for miRNAs in human disease states and discuss the influence of human genetic variation on miRNA-mediated regulation.
Repetitive Sequences in Complex Genomes: Structure and Evolution
Authors: Jurka Jerzy , Kapitonov Vladimir V. , Kohany Oleksiy , Jurka Michael V.
Published: September 2007

Eukaryotic genomes contain vast amounts of repetitive DNA derived from transposable elements (TEs). Large-scale sequencing of these genomes has produced an unprecedented wealth of information about the origin, diversity, and genomic impact of what was once thought to be “junk DNA.” This has also led to the identification of two new classes of DNA transposons, Helitrons and Polintons, as well as several new superfamilies and thousands of new families. TEs are evolutionary precursors of many genes, including RAG1, which plays a role in the vertebrate immune system. They are also the driving force in the evolution of epigenetic regulation and have a long-term impact on genomic stability and evolution. Remnants of TEs appear to be overrepresented in transcription regulatory modules and other regions conserved among distantly related species, which may have implications for our understanding of their impact on speciation.
Annotating Noncoding RNA Genes
Authors: Griffiths-Jones Sam
Published: September 2007

Noncoding RNA genes produce a functional RNA product rather than a translated protein. More than 1500 homologs of known “classical” RNA genes can be annotated in the human genome sequence, and automatic homology-based methods predict up to 5000 related sequences. Methods to predict novel RNA genes on a whole-genome scale are immature at present, but their use hints at tens of thousands of such genes in the human genome. Messenger RNA-like transcripts with no protein-coding potential are routinely discovered by high-throughput transcriptome analyses. Meanwhile, various experimental studies have suggested that the vast majority of the human genome is transcribed, although the proportion of the detected RNAs that is functional remains unknown.
Advancements in the Treatment of Epilepsy
Authors: Leeman B.A. , Cole A.J.
Published: September 2007

Diagnostic tools and treatment options for epilepsy have expanded in recent years. Imaging techniques once confined to research laboratories are now routinely used for clinical purposes. Medications that were unavailable a few years ago are now first-line agents. Patients with refractory seizures push for earlier surgical intervention, consider treatment with medical devices, and actively seek nonpharmacologic alternatives. We review some of these recent advances in the management of epilepsy.
Vesicular Neurotransmitter Transporters as Targets for Endogenous and Exogenous Toxic Substances
Authors: Chaudhry Farrukh A. , Edwards Robert H. , Fonnum Frode
Published: September 2007

Exocytotic release of neurotransmitters requires their accumulation inside preformed secretory vesicles. Distinct vesicular transport activities translocate classical transmitters into synaptic vesicles energized by a H+electrochemical gradient (ΔμH+), with subtle but important differences in dependence on the electrical and chemical components. The vesicular transporters also interact with toxic compounds and drugs. They mediate neuroprotection by sequestering toxic compounds as well as neurotransmitters into vesicles, reducing their concentration in the cytosol where they may have detrimental effects. Both therapeutic agents and psychostimulants interfering with vesicular transport have yielded insight into the pathogenesis of psychiatric as well as neurodegenerative diseases. Thus, specific inhibitors have helped to characterize both the physiological role and mechanism of vesicular neurotransmitter transport.
Apoptosis Signal-Regulating Kinase 1 in Stress and Immune Response
Authors: Takeda Kohsuke , Noguchi Takuya , Naguro Isao , Ichijo Hidenori
Published: September 2007

Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase (MAPK) kinase kinase of the c-Jun N-terminal kinase (JNK) and p38 MAPK pathways. ASK1 is preferentially activated by various cytotoxic stressors and plays pivotal roles in a wide variety of cellular response to them. Recent analyses of ASK1 orthologs in Caenorhabditis elegans and Drosophila melanogaster have revealed that ASK1 is an evolutionarily conserved signaling intermediate in stress responses and appears to constitute a primitive but efficient defense system against stimuli harmful to organisms. Consistent with this notion, ASK1 has been shown to be required for the innate immune response, which is essential for host defense against a wide range of pathogens. In this review, we focus on the molecular mechanisms by which ASK1 functions in stress and immune responses and discuss the possible involvement of ASK1 in human diseases.
Epigenetics and Complex Disease: From Etiology to New Therapeutics
Authors: Ptak Carolyn , Petronis Arturas
Published: September 2007

Epigenetics is a new development in complex non-Mendelian disease, which may not only uncover etiologic and pathogenic mechanisms but may also provide the basis for the development of medications that would target the primary epigenetic causes of such diseases. Such epigenetic drugs would be novel, potentially possessing substantially higher therapeutic potential and a much lower rate of adverse effects in comparison to current symptomatic treatments. A collection of epigenetic drugs already exist at various stages of development and, although their effectiveness has yet to be maximized, they show great promise in the treatment of cancer, psychiatric disorders, and other complex diseases. Here we present a review of the epigenetic theory of complex disease and an evaluation of current epigenetic therapies, as well as predictions of the future directions in this expanding field.
Social Bonds and Posttraumatic Stress Disorder
Authors: Charuvastra Anthony , Cloitre Marylene
Published: September 2007

Retrospective and prospective studies consistently show that individuals exposed to human-generated traumatic events carry a higher risk of developing Posttraumatic Stress Disorder (PTSD) than those exposed to other kinds of events. These studies also consistently identify perceptions of social support both before and after a traumatic event as an important factor in the determining vulnerability to the development of PTSD. We review the literature on interpersonal traumas, social support and risk for PTSD and integrate findings with recent advances in developmental psychopathology, attachment theory and social neuroscience. We propose and gather evidence for what we term the social ecology of PTSD, a conceptual framework for understanding how both PTSD risk and recovery are highly dependent on social phenomena. We explore clinical implications of this conceptual framework.
Multiple Gates for SOI MOSFETs : Two, Three or Four?
Authors: Cristoloveanu Sorin
Published: September 2007

The inexorable migration from single-gate to multiple-gate transistors is reviewed by attempting to look into the motivations, hesitations, achievements, implications and future challenges. Specific aspects related to the operation multiple-gate transistors are evoked with the aim of clarifying the strategic trends rather than the device-physics mechanisms. The road is difficult and dangerous, but hopefully long enough. The key words are nano, multiple-gates, innovative ideas and sound SOI technology.
Triple Gate FinFET Parameter Extraction Using High Frequency Capacitance - Voltage Curves
Authors: Rodrigues Michele , Sonnenberg Victor , Martino Joao A.
Published: September 2007

This work presents the characterization of triple Gate nMOS FinFET using high frequency Capacitance versus Voltage (CV) curves. Front channel capacitance as a function of the front and the back gate voltage is analyzed and used to determine Effective Oxide Thickness (EOT), fin height (Hfin) and the fin doping concentration (Nfin). Three-dimensional numerical simulations are performed to validate the proposed methods and also evaluated their sensitivity. The experimental results are in agreement with simulations results.
Low Temperature Operation of Undoped Body Triple-Gate FinFETs from an Analog Perspective
Authors: Pavanello Marcelo A. , Martino Joao A. , Simoen E. , Rooyackers R. , Collaert N. , Claeys C.
Published: September 2007

This paper studies the temperature reduction influence on some analog figures of merit of n-type triple-gate FinFETs with undoped body, using DC measurements. It is demonstrated that the temperature reduction improves the transconductance over drain current ratio in any operational region. On the other hand, the output conductance is degraded when the temperature is reduced. The combination of these effects shows that the intrinsic gain of a L=90 nm FinFET is degraded by 3 dB when the temperature reduces from 300 K down to 100 K. A comparison with planar single gate fully depleted SOI reveals that the temperature degradation of the output conductance in FinFETs is less temperature-dependent.
The Coherent FinFET
Authors: Da Cunha C. R.
Published: September 2007

A FinFET device was simulated using recursive Green's functions through Dyson's equation solved self-consistently with Poisson equation. The dimensions of the device are such that the transport is forced to be coherent through the whole structure. The results show that at the coherent regime the standard MOS transistor loses appropriate gate action and shows a small output resistance.
Distortion Analysis of Triple-Gate Transistor in Saturation
Authors: Conde Jorge E. , Cereira Antonio , Estrada M.
Published: September 2007

The nonlinear characteristics of multiple-gate transistors are of prime importance in the performance analysis for integrated circuit low signal analog applications. In this paper we present for the first time, the nonlinearity analysis of Triple-Gate Transistor in saturation with different channel lengths, Fin Heights and Fin Widths. I-V characteristics were obtained by 3-D simulation. The moderate inversion region is included. The Integral Function Method calculated the distortion figures HD2 and HD3.
Semiconductor Surface Cleaning and Conditioning Challenges Beyond Planar Silicon Technology
Authors: Ruzyllo Jerzy
Published: September 2007

The paper reviews the challenges semiconductor cleaning technology is facing in the light of: (i) advanced silicon technology moving in the direction of non-planar device structures such as 3D MOS gates, MEMS devices as well 1D nanowire-type structures, (ii) the need for modified cleans for semiconductors other than silicon, e.g. Ge and III-V compounds, and (iii) emerging needs to process surfaces of non-semiconductor substrates such as for instance sapphire in SOS (Silicon-On-Sapphire) material systems. It is concluded that in several areas significant modifications of the established cleaning technology are needed to meet emerging challenges.
Ultra-Thin Deformable Silicon Substrates with Lateral Segmentation and Flexible Metal Interconnect
Authors: Zoumpoulidis T. , Wang L. , Bartek M. , Jansen K. , Ernst L. J.
Published: September 2007

Our progress in developing technology modules for deformable single-crystalline-silicon electronics is presented in this contribution. Additional deformability/reliability is accomplished by modifications of the previously reported ultra-thin and flexible CIRCONFLEX technology (1). The flexibility is added in the last steps of the process flow using a combination of lateral segmentation and flexible metal interconnects. The post-processing nature of the added mechanical flexibility is thought to allow sensors and electronics to be built with proven technologies before they are rendered flexible. The additional deformability/reliability is achieved by lateral segmentation of silicon/dielectric layers and connecting these using flexible electrical interconnect. In the current study, segment thickness (silicon/SiO2) of ~1 μm, segment size between 150 and 450 μm, spacing of 20-200 μm and serpentine-shaped aluminum interconnect transferred onto 8- 10 μm thick polyimide film are characterized by tensile stretching to find out the reliability limits. Compared to our previous reports (2, 3), next to the processing issues also new electrical integrity results obtained from passive electrical test structures implemented on fully segmented polymer-embedded silicon islands are presented.
A Gravimetric Technique to Determine the Crystallite Size Distribution in High Porosity Nanoporous Silicon
Authors: Du Plessis M.
Published: September 2007

Nanoporous silicon structures were investigated for application in nano-explosive devices, where the porous structure is impregnated by an explosive oxidant. A large specific surface area is required for the nano-explosive surface reaction, which is normally only achieved with small pore diameters. A small pore diameter will reduce the impregnation efficiency of the oxidant within the nanoporous layer. To optimize the nano-explosive performance, it was necessary to determine the relationship between specific surface area and pore dimension. A gravimetric technique is described whereby the specific surface area can be determined, as well as the statistical distribution of crystallite diameters in the nanoporous structure. It is shown that the high porosity nanoporous silicon is best modeled as an array of cylindrical crystallites, rather than an array of pores. It is also demonstrated that the statistical distribution of the crystallite diameters can best be described by a log-normal distribution.
The Effect of Si-Substrate on the Optical Characterization of Ge Nanostructures Obtained by LPCVD
Authors: Mestanza S. N. , Rodriguez E. , Doi I. , Vaz A. R. , Frateschi N. C.
Published: September 2007

Germanium nanostructures (Ge-ns) were grown by Low Pressure Chemical Vapor Deposition on a SiO2 film. Samples were studied by micro-Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). We report the analysis of the influence of the silicon substrate on the Raman scattering spectra of the Ge-ns. Both the broadening and the small shift observed in the Raman peak can be attributed to the variation in the size distribution of the Ge-ns and the phonon confinement. AFM images show a Ge-ns density around 4x1010 cm-2, with a 20 nm mean size and 6 nm height. AFM and SEM images revealed an excellent agreement which could be used to estimate the size and size distribution of the nanostructures. Finally, the Raman spectra were fitted with a theoretical model to evaluate the average size and full-width at half-maximum.
ECR-CVD SiNX Passivation in GaAs-based MISFET Devices
Authors: Zoccal L. B. , Diniz J. A. , Fo J. G. , Daltrini A. , Swart J. W.
Published: September 2007

We have developed an excellent quality passivation silicon nitride on GaAs that requires no surface pre-treatment. The silicon nitride film is deposited (by Electron Cyclotron Resonance (ECR) Chemical Vapor Deposition (CVD)) directly over GaAs-n implanted with Si ions) layer formed in semi-insulating GaAs substrates, which are used for Metal-Insulator-Semiconductor Field Effect Transistor (MISFET). Optical emission spectrometry (OES) was used for ECR-CVD plasma characterization, and low formation of H and NH molecules in the gas phase was detected at pressure of 2 mTorr. The ECR depositions were carried out at a fixed substrate temperature of 20oC, SiH4/N2 flow ratio of 1, Ar flow of 5 sccm, pressure of 2 mTorr and microwave (2.45 GHz) power of 250W. We have applied this nitride to our GaAs MISFET fabrication process with excellent results, such as higher transconductances of MISFET devices in related to MESFETs Metal-Semiconductor FETs), which were used as control devices.
GaAs and AlGaAs reactive ion etching in SiCl4/Ar gas mixtures for HEMT applications
Authors: Nunes A. M. , Moshkalev S. A. , Tatsch P. J. , Duarte C. A. , Gusev G. M.
Published: September 2007

This work presents the AlGaAs and GaAs etching results using a RIE reactor and SiCl4/Ar plasma. These materials can be applied in HEMT devices fabrication. The influence of the process temperature on etch rates has been studied. Selectivity of etching and the importance of the periodical process chamber cleaning for SiCl4 containing gas mixtures are discussed. For optimized conditions, GaAs etch rate as high as ~50nm/min with low surface roughness, for process duration as long as 60 min, have been obtained.
Design of Finish Process of Freeform Surface in Magnetic-Assistance Electrochemical Finishing
Authors: Pa P. S.
Published: September 2007

This paper studies the performance assessment of magnetic-assistance electrochemical finishing using an effective design system and magnetic force to the electrolyte to assist the dregs discharge on zinc alloy beyond die casting by electrochemical finishing as a finish process on the freeform surface of castings. An outer shell of toy vehicle is taken for instance in the experiment. A small distance between the two magnets or large magnetic field intensity provides larger magnetic force and discharge ability. A higher current rating with magnetic-assistance can avoid the difficulty of dreg discharge, thus reducing the finish time. Pulsed direct current can slightly promote the finishing effect, but the machining time is increased. Thus the magnetic-assistance electrochemical finishing without pulsed current is recommended for the finish process. It is a great contribution that the magnetic-assistance electrochemical finishing just needs quite short to make the freeform surface of workpiece smooth and bright.
Electroless Deposition of CuNiP Alloys onto Silicon Surfaces
Authors: Parra F. T. , Dos Santos Filho S. G. , Marques A. E. , Martini S.
Published: September 2007

We have investigated electroless deposition of CuNiP alloys onto silicon wafer surfaces. Initially, surfaces were pre-activated in a diluted hydrofluoric acid solution containing PdCl2. Following, it was used an alkaline chemical bath having NiSO4, CuSO4, Na2HPO2, Na3C6H5O7, NH4Cl and NH4OH as constituents diluted in DI water. The concentration of copper salt in the deposition solution greatly affects the Cu content of the CuNiP deposits and thus the Ni and P contents. A procedure to extract the film stoichiometry is presented and good quality CuNiP alloys were obtained. Areal concentration and composition were measured by Rutherford Backscattering Spectrometry (RBS) and surface morphology was characterized by Atomic Force Microscopy (AFM). For the studied range of CuSO4 concentrations, it was inferred that the sparsely distributed sites of Pd on Si act predominantly as local catalysts for Cu (and not for Ni) deposition and, therefore, "Cu islands" are being formed at these sites and its deposition far from them is not eased because the Ni concentration was chosen at least fifty times higher than the Cu concentration. As a result, Ni deposition dominates far from Pd sites, possibly, as a layer-by-layer deposition.
Electrical Characterization of Platinum Thin Films Deposited by Focused Ion Beam
Authors: Da Silva M. M. , Vaz A. R. , Moshkalev S. A. , Swart J. W.
Published: September 2007

Dual beam FIB (focused ion beam)/SEM (scanning elelctron microscope) systems are commonly used for imaging, selective etch and deposition of materials like platinum. The paper presents the results of electrical characterization of platinum thin films deposited by focused ion beam. For measurements, two types of test structures were fabricated: (i) 150x150 :m and 20x20 :m squares with thickness of 5, 10, 30 and 100 nm, and (ii) 30 :m long resistors with variable cross - section (50 nm x 50nm to 1:m x 1:m). The Pt film resistivity has been measured by a four points probe method, to give the value of ~10 x 10-4 A.cm.
Novel Europium β-diketonate Complex in Organic Light Emitting Diode: Eu(BTA)3bipy [tris(1-(2-benzoyl)-3,3,3-trifluoroacetone))-bipyridine, Europium(III)]
Authors: Santos G. , Fonseca F. J. , Andrade A. M. , Braga S. S. , Coelho A. C. , Goncalves I. S. , Simoes W. , Pereira L.
Published: September 2007

This work shows, for the first time, an Organic Light Emitting Diode (OLED) with a rare earth Europium(III) organic complex as the emitting layer, in particular Eu(BTA)3bipy - [tris(1 - (2 - benzoyl) -3,3,3 - trifluoroacetone))-bipyridine, europium(III)]. The OLED has a three layer structure configuration using TPD - [N,N' - bis(3-methylphenyl) - N,N'-diphenylbenzidine] and Alq3 - [aluminum - tris(8 - hydroxyquinoline)] as hole and electron transport layers respectively. Electroluminescence of the device shows pure 4f6 Eu3+ transitions. The driving voltage is about 14 V and a normal electrical current operation of 1 - 2 mA. The wall plug efficiency is of about 3×10-3 %.
Clusters Formation by Rapid Thermal Annealing on SiO2/Ge and SiH/Ge Heterostructures
Authors: Dos Anjos A. M. , Diniz J. A. , Zoccal L. B. , Mengui U. A. , Canesqui M. A. , Doi I.
Published: September 2007

A series of amorphous-SiO2/Ge and amorphous-Si:H/Ge heterostructures with four different layer sequences were grown on p-type Si (001) substrates. Rapid Thermal Annealing (RTA) at 1000{degree sign}C during 40s was used to modify the film structure. The RTA effects were extracted from measures in a high-resolution x - ray diffractometer (HRXRD), micro-Raman (MR) and atomic force microscopy (AFM). Crystalline clusters with concentrations varying from 0.03 to 0.57 of Ge contents from different samples were obtained. Grain sizes from 3 to 6 nm were estimated. Amorphous-Si:H/Ge formed crystalline strained clusters, while amorphous-SiO2/Ge formed crystalline relaxed clusters.
Electromigration Modeling for Interconnect Structures in Microelectronics
Authors: Ceric H. , Selberherr S.
Published: September 2007

Electromigration is one of the most important reliability issues in semi- conductor technology. Its complex character demands comprehensive phys- ical modeling as basis for analysis. Simulation of electromigration induced interconnect failure focuses on the life-cycle of intrinsic voids, which con- sists of two distinct phases: void nucleation and void evolution. We present models for both phases as well as models which describe the impact of metal microstructure and mechanical stresses. These stresses have their sources in the fabrication process itself and in the material transport caused by elec- tromigration. Special emphasis is put on explaining the void morphology and its impact on interconnect resistance. Investigations for common two- and three-dimensional interconnect structures are presented. Implications of the theoretical analysis and the simulation results for modern intercon- nect design are discussed.
A Study Of Flicker Noise In MOS Transistor Under Switched Bias Condition
Authors: Miguez Matias , Arnaud Alfredo
Published: September 2007

This manuscript examines in detail the mechanisms and behavior of flicker noise in switched biased MOS transistors. Firstly, the PSD of a DC biased transistor is deduced using only Shockley- Read-Hall (SRH) statistics and the autocorrelation formalism. Then the analysis is extended, by means of simulations and using simple physical hypotheses, to a switched bias condition. The results allow explaining several reported experimental measurements. Particularly, the 1/f form of flicker noise at very low frequencies is observed in simulations; this behavior is not correctly addressed by previously reported noise models of switched MOSFET.
Analysis of Matching in Graded-Channel SOI MOSFETs
Authors: De Souza M. , Flandre D. , Pavanello Marcelo A.
Published: September 2007

This paper presents an analysis of mismatch in Graded-Channel (GC) SOI MOSFETs. Experimental results show that GC devices present poorer threshold voltage and drain current matching in comparison to conventional SOI counterpart. The analytical model for the drain current of GC devices is used to investigate the reasons for this matching worsening. Two-dimensional numerical simulations are used to predict the matching behavior both in linear and saturation regions.
Fundamentals, Computer Implementation and Applications of the Advanced Compact MOSFET (ACM) Model
Authors: Siebel O. F. , Schneider M. C. , Galup-Montoro C.
Published: September 2007

In this study we introduce a new computer implementation of the advanced compact MOSFET (ACM) model. The core ACM model, its computer implementation and some simulation tests are presented.
Improved Model to Determine the Generation Lifetime in Double Gate SOI nMOSFETs
Authors: Galeti M. , Martino Joao A. , Simoen E. , Claeys C.
Published: September 2007

This work reports on an improved model to determine the hole generation lifetime in Double Gate SOI nMOSFETs. This improved model is based on the drain current switch-off transient for partially depleted SOI devices and it is dependent on the silicon thickness. This model also considers the influence of the halo implanted region and the channel length reduction. The obtained results through this new technique with double gate devices were compared with experimental measurements and two-dimensional numerical simulations of the single gate devices showing a good agreement.
Electrical Studies on Metal /SrTa2O6 or TiO2/ Si Substrate Stack Systems
Authors: Awadelkarim O. O. , Jiang J. , Suliman S. A. , Sarpatwari K. , Passmore L. J. , Lee D.O.- , Roman P. , Ruzyllo Jerzy
Published: September 2007

SrTa2O6 or TiO2 high-k gate dielectrics is observed to have significantly different dependence on the temperature and the frequency of a capacitance-voltage measurement than that of the conventional metal-oxide-Si (MOS) capacitors. It is shown that this is due to contributions from the, often, inadvertently grown, and relatively poorer quality interfacial dielectric between the high-k material stack and the Si substrate. Although it is generally accepted that NH3 or NO nitridation of pre-high k-deposition Si surface is able to suppress the thickness of the dielectric layer, we found out that it does not necessarily improve the effective oxide thickness value, reduce the leakage current density and the interface state density, or protect the silicon substrate from the deposition related electrically active bulk Si deep traps.
Reversible Electrical Characteristics in PMMA on P3HT OTFTs
Authors: Mejia I. , Estrada M. , Cerdeira A. , Iniguez B.
Published: September 2007

The conjugated polymer Poly (3-Hexylthiophene) (P3HT) has attracted much attention as material for the fabrication of Organic Thin Film Transistors (OTFTs) because of its relatively high mobility. However, it has been reported that P3HT increases its conductivity when it is exposed to air or oxygen. In this paper, we studied the change in conductivity of P3HT layers annealed at different temperatures and atmospheres and demonstrate that the increase in conductivity of the P3HT layers after long exposure to air and N2 can be returned to its original value after annealing the device at 363 K in O2 at a pressure of 39.99 Pa (0.3 torr) for 30 min. The procedure was applied to OTFTs fabricated with Poly (3- Hexylthiophene) (P3HT) as active layer and Poly Methyl Methacrylate (PMMA) as dielectric, which were left to long exposure to air and N2, observing that their electrical characteristics returned exactly to their initial values.
A New Method for Polynomial Coefficient Extraction Applied to Harmonic Distortion Calculation
Authors: Ortiz-Conde A. , Garcia-Sanchez F. J. , Salazar R
Published: September 2007

A new method for the extraction of coefficients in an nth-order polynomial function is presented. The method may be used as an efficient tool to calculate any kth-order harmonic distortion in semiconductor devices for any input amplitude, without having to perform Fourier or AC analysis. To illustrate its utility, the calculation procedure has been applied to determine the harmonic distortion produced by the I-V output characteristics of an Independently Driven Double-Gate MOSFET. The accuracy of the results is analyzed as compared to the Weighted Least Squares algorithm. The calculated distortion harmonics are compared to those obtained by the use of traditional Fourier analysis.
Study of the Drain Leakage Current Behavior in Circular Gate SOI nMOSFET Using 0.13μm SOI CMOS Technology at High Temperatures
Authors: Almeida Luciano M. , Bellodi M.
Published: September 2007

It is presented numerical tridimensional simulations results concerning to the evolution of the drain leakage current behavior in Circular Gate SOI nMOSFETs operating from room temperature up to 573K. The results show that the leakage current behavior depends strongly on the channel length. Also, it was observed that the leakage current density distribution is non uniform along the silicon film thickness and it depends on the channel length and changes as the temperature goes up.
Coupled Quantum Dot Cell Dynamics
Authors: Stella M. F. , Batistuta M. V. , Da Costa J. C.
Published: September 2007

A simulation scheme was developed for the dynamic transport behavior of a number of laterally coupled double quantum dot cells. A simple one dimensional model was used for the wavefunction dynamics analysis and solving the electrostatic potentials. Behavior prediction and performance evaluation (i.e. settling time, frequency response) have been obtained. The developed simulation strategy allows the calculation of state transit times along chains of coupled quantum dots.
Impact of Graded-Channel SOI MOSFET Application on the Performance of Cascode and Wilson Current Mirrors
Authors: Santos A. A. , Flandre D. , Pavanello Marcelo A.
Published: September 2007

This work shows the impact of the use of graded-channel SOI MOSFETs (GC) in Wilson and Cascode current mirrors. The study was made through bi-dimensional simulations and experimental measurements, focusing on the mirroring precision, the output swing voltage (VOS) and output resistance of each architecture comparing with the conventional SOI devices. It was observed that the devices of graded-channel (GC) presented some improvement in the mirroring precision and a significant increase in the output resistance and output swing in all the architectures studied if compared to standard fully depleted SOI MOSFET. the setting time of GC current mirrors has been Also studied and has demonstrated improvements in relation to conventional SOI devices.
Improved Charge Sheet Model for PD SOI Sub-Micron MOSFETs
Authors: Alvarado J. , Cerdeira A. , Kilchytska V. , Flandre D.
Published: September 2007

This paper presents an Improved Charge Sheet Compact Model (ICSM) especially valuable to describe the nonlinearities present in the triode region and in the transfer characteristics in saturation. Modeled characteristics were compared with measured for analog PD SOI MOSFETs with body contact, having channel lengths from 220 nm to 120 nm. A very good agreement was observed for all analyzed I-V curves, derivatives and harmonic analysis. The model uses only analytical expressions and was implemented in SMARTSPICE.
Study of MOS Capacitors with Annealed TiO2 Gate Dielectric Layer
Authors: Albertin K. F. , Valle M. A. , Pereyra I.
Published: September 2007

MOS capacitors with TiO2 deposited with different O2 partial pressure (30,35 and 40%) and annealed at 550, 750 and 1000oC were fabricated and characterized. Rutherford Backscattering, Fourier Transform Infrared Spectroscopy and Elipsometry measurements were performed to characterize the TiO2 films. Capacitance-voltage (1MHz) and current-voltage measurements were utilized to obtain: the effective dielectric constant, the effective oxide thickness (EOT), the leakage current density (J) and the interface quality. The results show that the obtained TiO2 films present a dielectric constant varying from 40 to 170 and a leakage current density, for gate voltage (VG) of -1V, attaining values as low as 1 nA/cm2, appropriated for CMOS circuits fabrication, indicating that this material is a feasible substitute for current dielectric layers in order to prevent tunneling currents.