Fault-tolerant computer study

A set of building block circuits is described which can be used with commercially available microprocessors and memories to implement fault tolerant distributed computer systems. Each building block circuit is intended for VLSI implementation as a single chip. Several building blocks and associated processor and memory chips form a self checking computer module with self contained input output and interfaces to redundant communications buses. Fault tolerance is achieved by connecting self checking computer modules into a redundant network in which backup buses and computer modules are provided to circumvent failures. The requirements and design methodology which led to the definition of the building block circuits are discussed

Organsko-geohemijska korelacija nekih nafti depresije Drmno (južni deo panonskog basena, Jugoslavija)

The results of an investigation of crude oils originating from the Sirakovo and Bradarac-Maljurevac localities (southern part of the Pannonian Basin) are reported in this paper. The aim was to estimate the organic geochemical similarity of the crude oils fi om the DI mno (Kostolac) depression oil fields. The nine selected samples originated from reservoir. rocks of various depths. Reliable source and organic geochemical maturation parameters served as the basis for the correlation studies. The similar origin of the investigated DI mno depression crude oils was corroborated, characterized by a significant participation of terrestrial precursor biomass. They were shown to be of relatively low maturity and to have been formed during the earlier stages of the diagenet- ic-catagenetic sequence of processes leading to the formation of crude oils, most probably in source rocks of Tertiary age, corresponding to vitrinite reflectances between Ro = 0.70 % and Ro = 0.80%. The crude oils from Bradarac-Maljurevac seemed to be somewhat less homogeneous with respect to organic geochemical parameters compared to Sirakovo crude oils.U ovom radu ispitivani su uzorci sirovih nafti depresije Drmno (Kostolac) sa lokaliteta Sirakovo i Bradarac-Maljurevac. Cilj rada bio je da se proceni organsko-geohemijska ujednačenost nafti naftnih polja depresije Drmno. Izabrani su uzorci koji potiču iz rezervoarskih stena sa različitih dubina i u njima su određeni grupni i specifični izvorni i maturacioni organsko-geohemijski parametri. Potvrđeno je da ispitivani uzorci depresije Drmno imaju slično poreklo koje karakteriše veći udeo terestrijalne prekursorske biomase. Ispitivane nafte su nešto nižeg stepena maturisanosti i nastale su u ranijim fazama dijagenetsko-katagenetske sekvencije formiranja nafte kojima odgovaraju vrednosti refleksije vitrinita između Ro = 0,70 % i Ro = 0,80 %. Najverovatnije su nastale u izvornim stenama tercijarne starosti. Nafte sa lokaliteta Bradarac-Maljurevac karakteriše nešto niži nivo organsko-geohemijske homogenosti nego nafte sa lokaliteta Sirakovo

Fast Quantum Modular Exponentiation

We present a detailed analysis of the impact on modular exponentiation of architectural features and possible concurrent gate execution. Various arithmetic algorithms are evaluated for execution time, potential concurrency, and space tradeoffs. We find that, to exponentiate an n-bit number, for storage space 100n (twenty times the minimum 5n), we can execute modular exponentiation two hundred to seven hundred times faster than optimized versions of the basic algorithms, depending on architecture, for n=128. Addition on a neighbor-only architecture is limited to O(n) time when non-neighbor architectures can reach O(log n), demonstrating that physical characteristics of a computing device have an important impact on both real-world running time and asymptotic behavior. Our results will help guide experimental implementations of quantum algorithms and devices.Comment: to appear in PRA 71(5); RevTeX, 12 pages, 12 figures; v2 revision is substantial, with new algorithmic variants, much shorter and clearer text, and revised equation formattin

Combining leak--resistant arithmetic for elliptic curves defined over \F_p and RNS representation

In this paper we combine the residue number system (RNS) representation and the leak-resistant arithmetic on elliptic curves. These two techniques are relevant for implementation of elliptic curve cryptography on embedded devices.\\ % since they have leak-resistance properties. It is well known that the RNS multiplication is very efficient whereas the reduction step is costly. Hence, we optimize formulae for basic operations arising in leak-resistant arithmetic on elliptic curves (unified addition, Montgomery ladder) in order to minimize the number of modular reductions. We also improve the complexity of the RNS modular reduction step. As a result, we show how to obtain a competitive secured implementation.\\ Finally, %we recall the main advantages of the RNS representation, %especially in hardware and for embedded devices, and we show that, contrary to other approaches, ours takes optimally the advantage of a dedicated parallel architecture

Traganje za izvornim stenama nafti depresije Drmno, južni deo Panonskog basena, Srbija

In a search for source rocks of the crude oils of the Drmno depression (Southern part of the Pannonian Basin, Serbia), based on bulk and specific organic geochemical parameters, six out of eight Sirakovo, Bubusinac and Bradarac sedimentary core samples were found to possess typical source rock characteristics. By comparing the results observed for these sedimentary samples with the corresponding propel-ties of the crude oils from the Sirakovo and Bradarac oil-gas fields, a positive organic geochemical oil-source rock correlation was experienced for the first time within this basin. This finding may be considered as an important step towards the ultimate organic geochemical/geological interpretation of the Drmno depression.Ispitivani su sedimenti iz bušotina koje pripadaju lokacijama Sirakovo Bubušinac i Bradarac (depresija Drmno). Primenjene su organsko-geohemijske metode (određivanje sadržaja organskog ugljenika, bitumena i ugljovodonika, kao i određivanje raspodele i obilnosti bioloških markera tipa n-alkana izoprenoidnih alifatičnih alkana, triterpana i sterana) sa ciljem da se proceni njihova naftna potencijalnost. Za šest uzoraka utvrđen je visok stepen maturisanosti organske supstance, pripadnost "oil generation" fazi (Rr = 0,70 – 0,80 %), tercijarna starost i pretežno terestrijalno poreklo. Poređenjem sa sirovim naftama iz već otkrivenih naftnih ležišta bliskog lokaliteta (Sirakovo i Bradarac) utvrđena je značajna sličnost i prema maturisanosti i prema poreklu, na osnovu čega je između ispitivanih uzoraka sedimenata i nafti, prvi put kada je u pitanju depresija Drmno, definisana pozitivna korelacija nafta-izvorna stena

GSTM1 Modulates Expression of Endothelial Adhesion Molecules in Uremic Milieu

Deletion polymorphism of glutathione S-transferase M1 (GSTM1), a phase II detoxification and antioxidant enzyme, increases susceptibility to end-stage renal disease (ESRD) as well as the development of cardiovascular diseases (CVD) among ESRD patients and leads to their shorter cardiovascular survival. The mechanisms by which GSTM1 downregulation contributes to oxidative stress and inflammation in endothelial cells in uremic conditions have not been investigated so far. Therefore, the aim of the present study was to elucidate the effects of GSTM1 knockdown on oxidative stress and expression of a panel of inflammatory markers in human umbilical vein endothelial cells (HUVECs) exposed to uremic serum. Additionally, we aimed to discern whether GSTM1-null genotype is associated with serum levels of adhesion molecules in ESRD patients. HUVECs treated with uremic serum exhibited impaired redox balance characterized by enhanced lipid peroxidation and decreased antioxidant enzyme activities, independently of the GSTM1 knockdown. In response to uremic injury, HUVECs exhibited alteration in the expression of a series of inflammatory cytokines including retinol-binding protein 4 (RBP4), regulated on activation, normal T cell expressed and secreted (RANTES), C-reactive protein (CRP), angiogenin, dickkopf-1 (Dkk-1), and platelet factor 4 (PF4). GSTM1 knockdown in HUVECs showed upregulation of monocyte chemoattractant protein-1 (MCP-1), a cytokine involved in the regulation of monocyte migration and adhesion. These cells also have shown upregulated intracellular and vascular cell adhesion molecules (ICAM-1 and VCAM-1). In accordance with these findings, the levels of serum ICAM-1 and VCAM-1 (sICAM-1 and sVCAM-1) were increased in ESRD patients lacking GSTM1, in comparison with patients with the GSTM1-active genotype. Based on these results, it may be concluded that incubation of endothelial cells in uremic serum induces redox imbalance accompanied with altered expression of a series of cytokines involved in arteriosclerosis and atherosclerosis. The association of GSTM1 downregulation with the altered expression of adhesion molecules might be at least partly responsible for the increased susceptibility of ESRD patients to CVD

Is Increased Susceptibility to Balkan Endemic Nephropathy in Carriers of Common GSTA1 (*A/*B) Polymorphism Linked with the Catalytic Role of GSTA1 in Ochratoxin A Biotransformation? Serbian Case Control Study and In Silico Analysis

Although recent data suggest aristolochic acid as a putative cause of Balkan endemic nephropathy (BEN), evidence also exists in favor of ochratoxin A (OTA) exposure as risk factor for the disease. The potential role of xenobiotic metabolizing enzymes, such as the glutathione transferases (GSTs), in OTA biotransformation is based on OTA glutathione adducts (OTHQ-SG and OTB-SG) in blood and urine of BEN patients. We aimed to analyze the association between common GSTA1, GSTM1, GSTT1, and GSTP1 polymorphisms and BEN susceptibility, and thereafter performed an in silico simulation of particular GST enzymes potentially involved in OTA transformations. GSTA1, GSTM1, GSTT1 and GSTP1 genotypes were determined in 207 BEN patients and 138 non-BEN healthy individuals from endemic regions by polymerase chain reaction (PCR). Molecular modeling in silico was performed for GSTA1 protein. Among the GST polymorphisms tested, only GSTA1 was significantly associated with a higher risk of BEN. Namely, carriers of the GSTA1*B gene variant, associated with lower transcriptional activation, were at a 1.6-fold higher BEN risk than those carrying the homozygous GSTA1*A/*A genotype (OR = 1.6; p = 0.037). In in silico modeling, we found four structures, two OTB-SG and two OTHQ-SG, bound in a GSTA1 monomer. We found that GSTA1 polymorphism was associated with increased risk of BEN, and suggested, according to the in silico simulation, that GSTA1-1 might be involved in catalyzing the formation of OTHQ-SG and OTB-SG conjugates

Relapse in resected lung cancer revisited: does intensified follow up really matter? A prospective study

<p>Abstract</p> <p>Background</p> <p>beside the well known predominance of distant vs. loco-regional relapse, several aspects of the relapse pattern still have not been fully elucidated.</p> <p>Methods</p> <p>prospective, controlled study on 88 patients operated for non-small cell lung cancer (NSCLC) in a 15 months period. Stage IIIA existed in 35(39.8%) patients, whilst stages IB, IIA and IIB existed in 10.2%, 4.5% and 45.5% patients respectively. Inclusion criteria: stage I-IIIA, complete resection, systematic lymphadenectomy with at least 6 lymph node groups examined, no neoadjuvant therapy, exact data of all aspects of relapse, exact data about the outcome of the treatment.</p> <p>Results</p> <p>postoperative lung cancer relapse occurred in 50(56.8%) patients. Locoregional, distant and both types of relapse occurred in 26%, 70% and 4% patients respectively. Postoperative cancer relapse occurred in 27/35(77.1%) pts. in the stage IIIA and in 21/40(52.55) pts in the stage IIB. In none of four pts. in the stage IIA cancer relapse occurred, unlike 22.22% pts. with relapse in the stage IB. The mean disease free interval in the analysed group was 34.38 ± 3.26 months.</p> <p>The mean local relapse free and distant relapse free intervals were 55 ± 3.32 and 41.62 ± 3.47 months respectively Among 30 pts. with the relapse onset inside the first 12 month after the lung resection, in 20(66.6%) pts. either T3 tumours or N2 lesions existed. In patients with N0, N1 and N2 lesions, cancer relapse occurred in 30%, 55.6% and 70.8% patients respectively</p> <p>Radiographic aspect T stage, N stage and extent of resection were found as significant in terms of survival. Related to the relapse occurrence, although radiographic aspect and extent of resection followed the same trend as in the survival analysis, only T stage and N stage were found as significant in the same sense as for survival. On multivariate, only T and N stage were found as significant in terms of survival.</p> <p>Specific oncological treatment of relapse was possible in 27/50(54%) patients.</p> <p>Conclusion</p> <p>the intensified follow up did not increase either the proportion of patients detected with asymptomatic relapse or the number of patients with specific oncological treatment of relapse.</p