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2012
Bahubalindruni, Ganga, Duarte, Candido, Tavares, Vitor Grade, Barquinha, Martins, Fortunato, de Oliveira PG.  2012.  Multipliers with transparent a-GIZO TFTs using a neural model. 20th Telecommunications Forum (TELFOR). , Belgrade
Mouquinho, AI, Petrova K, Barros MT, Sotomayor J.  2012.  New Polymer Networks for PDLC Films Application. New Polymers for Special Applications . (A. De-Souza-Gomes, Ed.).:139-164., Rijeka: InTech
Morgado, L, Fernandes AP, Dantas JM, Silva MA, Salgueiro CA.  2012.  On the road to improve the bioremediation and electricity-harvesting skills of Geobacter sulfurreducens: functional and structural characterization of multihaem cytochromes. Biochemical Society transactions. 40(6):1295-1301. AbstractWebsite

Extracellular electron transfer is one of the physiological hallmarks of Geobacter sulfurreducens, allowing these bacteria to reduce toxic and/or radioactive metals and grow on electrode surfaces. Aiming to functionally optimize the respiratory electron-transfer chains, such properties can be explored through genetically engineered strains. Geobacter species comprise a large number of different multihaem c-type cytochromes involved in the extracellular electron-transfer pathways. The functional characterization of multihaem proteins is particularly complex because of the coexistence of several microstates in solution, connecting the fully reduced and oxidized states. NMR spectroscopy has been used to monitor the stepwise oxidation of each individual haem and thus to obtain information on each microstate. For the structural study of these proteins, a cost-effective isotopic labelling of the protein polypeptide chains was combined with the comparative analysis of 1H-13C HSQC (heteronuclear single-quantum correlation) NMR spectra obtained for labelled and unlabelled samples. These new methodological approaches allowed us to study G. sulfurreducens haem proteins functionally and structurally, revealing functional mechanisms and key residues involved in their electron-transfer capabilities. Such advances can now be applied to the design of engineered haem proteins to improve the bioremediation and electricity-harvesting skills of G. sulfurreducens.

Dantas, JM, Morgado L, Londer YY, Fernandes AP, Louro RO, Pokkuluri PR, Schiffer M, Salgueiro CA.  2012.  Pivotal role of the strictly conserved aromatic residue F15 in the cytochrome c7 family. Journal of Biological Inorganic Chemistry. 17(1):11-24. AbstractWebsite

Cytochromes c7 are periplasmic triheme proteins that have been reported exclusively in δ-proteobacteria. The structures of five triheme cytochromes identified in Geobacter sulfurreducens and one in Desulfuromonas acetoxidans have been determined. In addition to the hemes and axial histidines, a single aromatic residue is conserved in all these proteins - phenylalanine 15 (F15). PpcA is a member of the G. sulfurreducens cytochrome c7 family that performs electron/proton energy transduction in addition to electron transfer that leads to the reduction of extracellular electron acceptors. For the first time we probed the role of the F15 residue in the PpcA functional mechanism, by replacing this residue with the aliphatic leucine by site-directed mutagenesis. The analysis of NMR spectra of both oxidized and reduced forms showed that the heme core and the overall fold of the mutated protein were not affected. However, the analysis of 1H-15N heteronuclear single quantum coherence NMR spectra evidenced local rearrangements in the α-helix placed between hemes I and III that lead to structural readjustments in the orientation of heme axial ligands. The detailed thermodynamic characterization of F15L mutant revealed that the reduction potentials are more negative and the redox-Bohr effect is decreased. The redox potential of heme III is most affected. It is of interest that the mutation in F15, located between hemes I and III in PpcA, changes the characteristics of the two hemes differently. Altogether, these modifications disrupt the balance of the global network of cooperativities, preventing the F15L mutant protein from performing a concerted electron/proton transfer.

Gomes, PJ, Coelho M, Dionísio M, Ribeiro PA, Raposo M.  2012.  Probing radiation damage by alternated current conductivity as a method to characterize electron hopping conduction in DNA molecules. Applied Physics Letters. 101(12):123702-1-4.Website
SCUTARU, G, SANDU F, COCORADA E, PAVALACHE M, KRISTALY D, Gomes L, Coito F, MÖRSKY-LINDQUIST AK, CSEREY S, DASC{\u A}LU M, Others.  2012.  RELAZIONE SUGLI ASPETTI FORMATIVI. Abstract

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Gouveia, JP, Dias L, Fortes P, Seixas J.  2012.  TIMES_PT: Integrated Energy System Modeling. 1st Int'l Workshop on Information Technology for Energy Applications (IT4ENERGY'2012). , Lisbon, Portugal: Vol. 923 of CEUR Workshop Proceedings, ISSN 1613-0073
Vale, T, Dias RJ.  2012.  TribuSTM Instrumentation Rules. , Lisboa: Departamento de Informática FCT/UNLtribustm_instrumentation_rules.pdf
Vale, TM, Dias RJ, Lourenço JM.  2012.  Uma Infraestrutura para Suporte de Memória Transacional Distribuída. Proceedings of INForum Simpósio de Informática. :177–189., Lisbon, Portugal: Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa Abstract2012-inforum-tv.pdf

As técnicas e algoritmos desenvolvidos sobre diferentes infraestruturas específicas dificilmente podem ser comparados entre si. Este princípio também se aplica às infraestruturas para execução de Memória Transacional Distribuída (MTD), pois não só são muito escassas aquelas que permitem o desenvolvimento, teste e comparação de vários algoritmos e técnicas de implementação, como fornecem uma interface intrusiva para o programador. Sem uma comparação justa, não é possível aferir quais as técnicas e algoritmos mais apropriados em cada contexto de utilização (workload). Neste artigo propomos uma infraestrutura generalista, muito flexível, que possibilita a experimentação de várias estratégias de MTD, permitindo o desenvolvimento de uma grande variedade de algoritmos e de técnicas de implementação eficientes e otimizadas. Através da sua utilização, é agora possível a comparação de técnicas e algoritmos em diferentes contextos de utilização (workloads), recorrendo a uma única infraestrutura e com implicações mínimas no código da aplicação.

Carvalho, T, Augusto V, Brás AR, Lourenço NMT, Afonso CAM, Barreiros S, Correia NT, Vidinha P, Cabrita EJ, Dias CJ, Dionísio M, Roling B.  2012.  Understanding the Ion Jelly Conductivity Mechanism. The Journal of Physical Chemistry B. 116(9):2664-2676.Website
Branco, RJF, Dias AMGC, Roque ACA.  2012.  Understanding the molecular recognition between antibody fragments and protein A biomimetic ligand. Journal of Chromatography A. 1244:106-115. AbstractWebsite

Affinity chromatography with protein A from Staphylococcus aureus (SpA) is the most widespread and
accepted methodology for antibody capture during the downstream process of antibody manufacturing.
A triazine based ligand (ligand 22/8) was previously developed as an inexpensive and robust alternative
to SpA chromatography (Li et al. [12] and Teng et al. [11]). Despite the experimental success, there is no
structural information on the binding modes of ligand 22/8 to antibodies, namely to Immunoglobulin G
(IgG) molecules and fragments. In this work, we addressed this issue by a molecular docking approach
allied to molecular dynamics simulations. Theoretical results confirmed the preference of the synthetic
ligand to bind IgG through the binding site found in the crystallographic structure of the natural complex
between SpA and the Fc fragment of IgG. Our studies also suggested other unknown “hot-spots” for
specific binding of the affinity ligand at the hinge between VH and CH1 domains of Fab fragment. The best
docking poses were further analysed by molecular dynamics studies at three different protonation states
(pH 3, 7 and 11). The main interactions between ligand 22/8 and the IgG fragments found at pH 7 were
weaker at pH 3 and pH 11 and in these conditions the ligand start losing tight contact with the binding
site, corroborating the experimental evidence for protein elution from the chromatographic adsorbents
at these pH conditions.

Dias, RJ, Distefano D, Seco JC, Lourenço JM.  2012.  Verification of Snapshot Isolation in Transactional Memory Java Programs. ECOOP 2012 – Object-Oriented Programming. 7313(James Noble, Ed.).:640-664., Beijing, China: Springer Berlin Heidelberg Abstract2012-ecoop.pdf

This paper presents an automatic verification technique for transactional memory Java programs executing under snapshot isolation level. We certify which transactions in a program are safe to execute under snapshot isolation without triggering the write-skew anomaly, opening the way to run-time optimizations that may lead to considerable performance enhancements. Our work builds on a novel deep-heap analysis technique based on separation logic to statically approximate the read- and write-sets of a transactional memory Java program. We implement our technique and apply our tool to a set of micro benchmarks and also to one benchmark of the STAMP package. We corroborate known results, certifying some of the examples for safe execution under snapshot isolation by proving the absence of write-skew anomalies. In other cases our analysis has identified transactions that potentially trigger previously unknown write-skew anomalies.

Dias, RJ, Vale TM, Lourenço JM.  2012.  Write-Write Conflict Detection for Distributed TM Systems. Talk presented at the 1st Euro-TM Workshop on Distributed Transactional Memory (WDTM'12). , Lisbon, Portugal Abstractwdstm-2012.pdf

Typical Distributed Transactional Memory (DTM) systems provide serializability by detecting read-write conflicts between accesses to shared data objects. Detecting read-write conflicts requires the bookkeeping of all the read and write accesses to the shared objects made inside the transaction, and the validation of all these accesses in the end of a transaction. For most DTM algorithms, the validation of a transaction requires the broadcast of its read-set to all the nodes of the distributed system during the commit phase. Since applications tend to read more than write, the overhead associated with the bookkeeping of read accesses, and the amount of network traffic generated during the commit, is a main performance problem in DTM systems. Database systems frequently rely on weaker isolation models to improve performance. In particular, Snapshot Isolation (SI) is widely used in industry. An interesting aspect of SI is that only write-write conflicts are checked at commit time and considered for detecting conflicting transactions. As main result, a DTM using this isolation model does not need to keep track of the read accesses, considerably reducing the bookkeeping overhead, and also eliminates the need of broadcasting the read-set at transaction commit time, thus reducing the network traffic and considerably increase the scalability of the whole system. By only detecting write-write conflicts, this isolation model allows a much higher commit rate, which comes at the expense of allowing some real conflicting transactions to commit. Thus, relaxing the isolation of a transactional program may lead previously correct programs to misbehave due to the anomalies resulting from malign data-races that are now allowed by the relaxed transactional run-time. These anomalies can be precisely characterized, and are often called in the literature as write-skew anomalies. Write-skew anomalies can be avoided dynamically with the introduction of algorithms that verify the serializability of running transactions, which may result in a non-negligible overhead. Our approach is to avoid the run-time overhead by statically asserting that a DTM program will execute without generating write-skew anomalies at runtime, while only verifying write-write conflicts. Conflicting transactions can be made “safe” by code rewriting using well known techniques. Our verification technique uses separation logic, a logic for verifying intensive heap manipulation programs, which was extended to construct abstract read- and write-sets for each transaction in the DTM program. This verification technique is implemented in the StarTM tool, which analyzes transactional Java bytecode programs. The transactions that cannot be verified by our tool are executed under serializable isolation (detecting read-write conflicts), while for the “safe” transactions we only detect write-write conflicts. The results of our experiments when verifying micro-benchmarks, such as linked lists and binary trees, and partially verifying some macro-benchmarks, such as the STAMP benchmark, strongly encourage the ongoing work for the application of this technique to DTM.

Antunes, R, Coito F, Duarte-Ramos H.  2012.  Improving Operator Performance through the Use of a Multivariable Human-Machine Control Strategy. Technological Innovation for Value Creation. :95–104.: Springer Boston Abstract

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Conde, J, c}alo Doria G{\c, Baptista {PV}.  2012.  Noble metal nanoparticles applications in cancer. Journal of drug delivery. 2012:751075.: Hindawi Publishing Corporation Abstract

Nanotechnology has prompted new and improved materials for biomedical applications with particular emphasis in therapy and diagnostics. Special interest has been directed at providing enhanced molecular therapeutics for cancer, where conventional approaches do not effectively differentiate between cancerous and normal cells; that is, they lack specificity. This normally causes systemic toxicity and severe and adverse side effects with concomitant loss of quality of life. Because of their small size, nanoparticles can readily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. This way, a variety of nanoparticles with the possibility of diversified modification with biomolecules have been investigated for biomedical applications including their use in highly sensitive imaging assays, thermal ablation, and radiotherapy enhancement as well as drug and gene delivery and silencing. Here, we review the available noble metal nanoparticles for cancer therapy, with particular focus on those already being translated into clinical settings.

Pimenta, J, Dias FMV, Marques CC, Baptista MC, Vasques MI, Horta AEM, Barbas JP, Soares R, Mesquita P, Cabrita E, Fontes C, Prates JA, Pereira RM.  2012.  The Prion-like Protein Doppel Enhances Ovine Spermatozoa Fertilizing Ability. Reproduction in Domestic Animals. 47:196-202. Abstract

The function of prion-like protein Doppel was suggested to be related to male fertility. In this study, the importance of ovine Doppel polypeptide on spermatozoa capacitation and fertilization was evaluated. After refolding, recombinant Doppel (rDpl) was supplemented with different concentrations (40, 80 or 190 ng/ml) to ovine spermatozoa during the capacitation process. In experiment 1, post-thawed ovine spermatozoa were incubated with different concentrations of rDpl during 1 h for swim-up, and changes in sperm motility, concentration, vigour, viability and capacitation were monitored (10 replicates). In experiment 2, the fertilization ability of post-swim-up spermatozoa incubated as above was tested through heterologous fertilization of bovine in vitro matured oocytes (n = 423, three replicates). Regardless of dosage, rDpl improved (p = 0.03) spermatozoa viability. Sperm individual motility and vigour were the highest (p = 0.04) for the group receiving 190 ng/ml rDpl. Sperm supplemented with the highest doses of rDpl achieved higher (p = 0.02) fertilization rates (56.0 +/- 3.0%) than control (39.1 +/- 2.2%) and 40 ng/ml rDpl (39.8 +/- 2.7%). Preliminary data suggest that Doppel protein may enhance in vitro spermatozoa fertilizing ability.

Pereira, AS, Timoteo CG, Guilherme M, Folgosa F, Naik SG, Duarte AG, Huynh BH, Tavares P.  2012.  Spectroscopic Evidence for and Characterization of a Trinuclear Ferroxidase Center in Bacterial Ferritin from Desulfovibrio vulgaris Hildenborough. Journal Of The American Chemical Society. {134}:{10822-10832}., Number {26} Abstract

Ferritins are ubiquitous and can be found in practically all organisms that utilize Fe. They are composed of 24 subunits forming a hollow sphere with an inner cavity of similar to 80 angstrom in diameter. The main function of ferritin is to oxidize the cytotoxic Fe2+ ions and store the oxidized Fe in the inner cavity. It has been established that the initial step of rapid oxidation of Fe2+ (ferroxidation) by H-type ferritins, found in vertebrates, occurs at a diiron binding center, termed the ferroxidase center. In bacterial ferritins, however, X-ray crystallographic evidence and amino acid sequence analysis revealed a trinuclear Fe binding center comprising a binuclear Fe binding center (sites A and B), homologous to the ferroxidase center of H-type ferritin, and an adjacent mononuclear Fe binding site (site C). In an effort to obtain further evidence supporting the presence of a trinuclear Fe binding center in bacterial ferritins and to gain information on the states of the iron bound to the trinuclear center, bacterial ferritin from Desulfovibrio vulgaris (DvFtn) and its E130A variant was loaded with substoichiometric amounts of Fe2+, and the products were characterized by Mossbauer and EPR spectroscopy. Four distinct Fe species were identified: a paramagnetic diferrous species, a diamagnetic diferrous species, a mixed valence Fe2+Fe3+ species, and a mononuclear Fe2+ species. The latter three species were detected in the wild-type DvFtn, while the paramagnetic diferrous species was detected in the E130A variant. These observations can be rationally explained by the presence of a trinuclear Fe binding center, and the four Fe species can be properly assigned to the three Fe binding sites. Further, our spectroscopic data suggest that (1) the fully occupied trinuclear center supports an all ferrous state, (2) sites B and C are bridged by a mu-OH group forming a diiron subcenter within the trinuclear center, and (3) this subcenter can afford both a mixed valence Fe2+Fe3+ state and a diferrous state. Mechanistic insights provided by these new findings are discussed and a minimal mechanistic scheme involving O-O bond cleavage is proposed.

Sousa, AMM, Morais S, Abreu MH, Pereira R, Sousa-Pinto I, Cabrita EJ, Delerue-Matos C, Gonca̧lves MP.  2012.  Structural, Physical, and Chemical Modifications Induced by Microwave Heating on Native Agar-like Galactans. Jornal of Agricultural and Food Chemistry. 60:4977-4985. Abstract

Native agars from Gracilaria vermiculophylla produced in sustainable aquaculture systems (IMTA) were extracted under conventional (TWE) and microwave (MAE) heating. The optimal extracts from both processes were compared in terms of their properties. The agars’ structure was further investigated through Fourier transform infrared and NMR spectroscopy. Both samples showed a regular structure with an identical backbone, β-D-galactose (G) and 3,6-anhydro-α-L-galactose (LA) units; a considerable degree of methylation was found at C6 of the G units and, to a lesser extent, at C2 of the LA residues. The methylation degree in the G units was lower for MAEopt agar; the sulfate content was also reduced. MAE led to higher agar recoveries with drastic extraction time and solvent volume reductions. Two times lower values of [η] and Mv obtained for the MAEopt sample indicate substantial depolymerization of the polysaccharide backbone; this was reflected in its gelling properties; yet it was clearly appropriate for commercial application in soft-texture food products.

Carvalho, T, Augusto V, Brás AR, c}o L{\cNMT, Afonso CAM, Barreiros S, Correia NT, Vidinha P, Cabrita EJ, Dion{\'ısio M, Roling B.  2012.  Understanding the Ion Jelly Conductivity Mechanism. Journal of Physical Chemistry B. 116:2664-2676. Abstract

The properties of the light flexible device, ion jelly, which combines gelatin with an ionic liquid (IL) were recently reported being promising to develop safe and highly conductive electrolytes. This article aims for the understanding of the ion jelly conductive mechanism using dielectric relaxation spectroscopy (DRS) in the frequency range 10-1-106 Hz; the study was complemented with differential scanning calorimetry (DSC) and pulse field gradient nuclear magnetic resonance (PFG NMR) spectroscopy. The room temperature ionic liquid 1-butyl-3-methylimmidazolium dicyanamide (BMIMDCA) used as received (1.9% w/w water content) and with 6.6% (w/w) of water content and two ion jellies with two different ratios BMIMDCA/gelatin/water % (w/w), IJ1 (41.1/46.7/12.2) and IJ3 (67.8/25.6/6.6), have been characterized. A glass transition was detected by DSC for all materials allowing for classifying them as glass formers. For the ionic liquid, it was observed that the glass transition temperature decreases with the increase of water content. While in subsequent calorimetric runs crystallization was observed for BMIMDCA with negligible water content, no crystallization was detected for any of the ion jelly materials upon themal cycling. To the dielectric spectra of all tested materials, both dipolar relaxation and conductivity contribute; at the lowest frequencies, electrode and interfacial polarization highly dominate. Conductivity, which manifests much more intensity relative to dipolar reorientations, strongly evidences subdiffusive ion dynamics at high frequencies. From dielectric measures, transport properties as mobility and diffusion coefficients were extracted. Data treatment was carried out in order to deconvolute the average diffusion coefficients estimated from dielectric data in its individual contributions of cations (D+) and anions (D-). The D+ values thus obtained for IJ3, the ion jelly with the highest IL/gelatin ratio, cover a large temperature range up to room temperature and revealed excellent agreement with direct measurements from PFG NMR, obeying to the same VFT equation. For BMIMDCA6.6%water, which has the same water amount as IJ3, the diffusion coefficients were only estimated from DRS measurements over a limited temperature range; however, a single VFT equation describes both DRS and PFG NMR data. Moreover, it was found that the diffusion coefficients and mobility are similar for the ionic liquid and IJ3, which points to a role of both water and gelatin weakening the contact ion pair, facilitating the translational motion of ions and promoting its dissociation; nevertheless, it is conceivable that a critical composition of gelatin that leads to those properties. The VFT temperature dependence observed for the conductivity was found to be determined by a similar dependence of the mobility. Both conductivity and segmental motion revealed to be correlated as inferred by the relatively low values of the decoupling indexes. The obtained results show that ion jelly could be in fact a very promising material to design novel electrolytes for different electrochemical devices, having a performance close to the IL but presenting an additional stability regarding electrical measurements and resistance against crystallization relative to the bulk ionic liquid.

2011
Dias, RJ, Seco JC, Lourenço JM.  2011.  Detection of Snapshot Isolation Anomalies in Software Transactional Memory: A Static Analysis Approach, UNL-DI-5-2011. : Universidade Nova de Lisboa2011-dias.pdf
Timoteo, CG, Pereira AS, Martins CE, Naik SG, Duarte AG, Moura JJ, Tavares P, Huynh BH, Moura I.  2011.  Low-spin heme b(3) in the catalytic center of nitric oxide reductase from Pseudomonas nautica, May 24. Biochemistry. 50:4251-62., Number 20 AbstractWebsite

Respiratory nitric oxide reductase (NOR) was purified from membrane extract of Pseudomonas (Ps.) nautica cells to homogeneity as judged by polyacrylamide gel electrophoresis. The purified protein is a heterodimer with subunits of molecular masses of 54 and 18 kDa. The gene encoding both subunits was cloned and sequenced. The amino acid sequence shows strong homology with enzymes of the cNOR class. Iron/heme determinations show that one heme c is present in the small subunit (NORC) and that approximately two heme b and one non-heme iron are associated with the large subunit (NORB), in agreement with the available data for enzymes of the cNOR class. Mossbauer characterization of the as-purified, ascorbate-reduced, and dithionite-reduced enzyme confirms the presence of three heme groups (the catalytic heme b(3) and the electron transfer heme b and heme c) and one redox-active non-heme Fe (Fe(B)). Consistent with results obtained for other cNORs, heme c and heme b in Ps. nautica cNOR were found to be low-spin while Fe(B) was found to be high-spin. Unexpectedly, as opposed to the presumed high-spin state for heme b(3), the Mossbauer data demonstrate unambiguously that heme b(3) is, in fact, low-spin in both ferric and ferrous states, suggesting that heme b(3) is six-coordinated regardless of its oxidation state. EPR spectroscopic measurements of the as-purified enzyme show resonances at the g approximately 6 and g approximately 2-3 regions very similar to those reported previously for other cNORs. The signals at g = 3.60, 2.99, 2.26, and 1.43 are attributed to the two charge-transfer low-spin ferric heme c and heme b. Previously, resonances at the g approximately 6 region were assigned to a small quantity of uncoupled high-spin Fe(III) heme b(3). This assignment is now questionable because heme b(3) is low-spin. On the basis of our spectroscopic data, we argue that the g = 6.34 signal is likely arising from a spin-spin coupled binuclear center comprising the low-spin Fe(III) heme b(3) and the high-spin Fe(B)(III). Activity assays performed under various reducing conditions indicate that heme b(3) has to be reduced for the enzyme to be active. But, from an energetic point of view, the formation of a ferrous heme-NO as an initial reaction intermediate for NO reduction is disfavored because heme [FeNO](7) is a stable product. We suspect that the presence of a sixth ligand in the Fe(II)-heme b(3) may weaken its affinity for NO and thus promotes, in the first catalytic step, binding of NO at the Fe(B)(II) site. The function of heme b(3) would then be to orient the Fe(B)-bound NO molecules for the formation of the N-N bond and to provide reducing equivalents for NO reduction.

Mathies, G, Blok H, Disselhorst JA, Gast P, van der Meer H, Miedema DM, Almeida RM, Moura JJ, Hagen WR, Groenen EJ.  2011.  Continuous-wave EPR at 275GHz: application to high-spin Fe(3+) systems, May. J Magn Reson. 210:126-32., Number 1 AbstractWebsite

The 275GHz electron-paramagnetic-resonance spectrometer we reported on in 2004 has been equipped with a new probe head, which contains a cavity especially designed for operation in continuous-wave mode. The sensitivity and signal stability that is achieved with this new probe head is illustrated with 275GHz continuous-wave spectra of a 1mM frozen solution of the complex Fe(III)-ethylenediamine tetra-acetic acid and of 10mM frozen solutions of the protein rubredoxin, which contains Fe(3+) in its active site, from three different organisms. The high quality of the spectra of the rubredoxins allows the determination of the zero-field-splitting parameters with an accuracy of 0.5GHz. The success of our approach results partially from the enhanced absolute sensitivity, which can be reached using a single-mode cavity. At least as important is the signal stability that we were able to achieve with the new probe head.

Dias, RJ, Lourenço JM, Preguiça N.  2011.  Efficient and Correct Transactional Memory Programs Combining Snapshot Isolation and Static Analysis, May. Proceedings of the 3rd USENIX Conference on Hot Topics in Parallelism (HotPar'11). , Berkeley, USA: Usenix Association Abstract2011-hotpar.pdf

Concurrent programs may suffer from concurrency anomalies that may lead to erroneous and unpredictable program behaviors. To ensure program correctness, these anomalies must be diagnosed and corrected. This paper addresses the detection of both low- and high-level anomalies in the Transactional Memory setting. We propose a static analysis procedure and a framework to address Transactional Memory anomalies. We start by dealing with the classic case of low-level dataraces, identifying concurrent accesses to shared memory cells that are not protected within the scope of a memory transaction. Then, we address the case of high-level dataraces, bringing the programmer's attention to pairs of memory transactions that were misspecified and should have been combined into a single transaction. Our framework was applied to a set of programs, collected form different sources, containing well known low- and high-level anomalies. The framework demonstrated to be accurate, confirming the effectiveness of using static analysis techniques to precisely identify concurrency anomalies in Transactional Memory programs.

Mota, CS, Valette O, Gonzalez PJ, Brondino CD, Moura JJ, Moura I, Dolla A, Rivas MG.  2011.  Effects of molybdate and tungstate on expression levels and biochemical characteristics of formate dehydrogenases produced by Desulfovibrio alaskensis NCIMB 13491, Jun. J Bacteriol. 193:2917-23., Number 12 AbstractWebsite

Formate dehydrogenases (FDHs) are enzymes that catalyze the formate oxidation to carbon dioxide and that contain either Mo or W in a mononuclear form in the active site. In the present work, the influence of Mo and W salts on the production of FDH by Desulfovibrio alaskensis NCIMB 13491 was studied. Two different FDHs, one containing W (W-FDH) and a second incorporating either Mo or W (Mo/W-FDH), were purified. Both enzymes were isolated from cells grown in a medium supplemented with 1 muM molybdate, whereas only the W-FDH was purified from cells cultured in medium supplemented with 10 muM tungstate. We demonstrated that the genes encoding the Mo/W-FDH are strongly downregulated by W and slightly upregulated by Mo. Metal effects on the expression level of the genes encoding the W-FDH were less significant. Furthermore, the expression levels of the genes encoding proteins involved in molybdate and tungstate transport are downregulated under the experimental conditions evaluated in this work. The molecular and biochemical properties of these enzymes and the selective incorporation of either Mo or W are discussed.

Pessanha, V, Dias RJ, Lourenço JM, Farchi E, Sousa D.  2011.  Practical verification of high-level dataraces in transactional memory programs, July. Proceedings of 9th the Workshop on Parallel and Distributed Systems: Testing, Analysis, and Debugging. :26–34., New York, NY, USA: ACM Abstract2011-padtad.pdf

In this paper we present MoTh, a tool that uses static analysis to enable the automatic verification of concurrency anomalies in Transactional Memory Java programs. Currently MoTh detects high-level dataraces and stale-value errors, but it is extendable by plugging-in sensors, each sensor implementing an anomaly detecting algorithm. We validate and benchmark MoTh by applying it to a set of well known concurrent buggy programs and by close comparison of the results with other similar tools. The results achieved so far are very promising, yielding good accuracy while triggering only a very limited number of false warnings.

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