In search of a “Non-citation index” indicator for scientific activity assessment in less developed countries. Case study of Croatia/Yugoslavia

The meaning of the term the intellectual island effect which was introduced byArunachalam et al. is broadened as to characterize the status of science on the periphery in general. A practical solution is proposed, based on bibliometric data of the research output and relying on two criteria: the extent of coverage by world significant secondary literature and the extent of scatter of that literature. Reliability of the publication data retrieved from the Citation Indexes is discussed; a measure is offered to assess the adequacy of the Citation Indexes as the data sources.Unquestionably, there has been no one like Einstein in physics in this century, but one has to reflect on how easily Einstein might have been lost, particularly if he had been born in a developing country.From C. M. KINNON, (Ed.)The Impact of Modern Scientific Ideas on Society Reidel/UNESCO, 1981, p. 29.     

Parallel general prefix computations with geometric,algebraic, and other applications

We introduce a generic problem component that captures the most common, difficult kernel of many problems. This kernel involves general prefix computations (GPC). GPC's lower bound complexity of (n logn) time is established, and we give optimal solutions on the sequential model inO(n logn) time, on the CREW PRAM model inO(logn) time, on the BSR (broadcasting with selective reduction) model in constant time, and on mesh-connected computers inO(n) time, all withn processors, plus anO(log² n) time solution on the hypercube model. We show that GPC techniques can be applied to a wide variety of geometric (point set and tree) problems, including triangulation of point sets, two-set dominance counting, ECDF searching, finding two-and three-dimensional maximal points, the reconstruction of trees from their traversals, counting inversions in a permutation, and matching parentheses.work partially supported by NSF IRI/8709726work partially supported by NSERC.     

Strengthening of alloy 8090 and its fracture mechanics parameters

An investigation has been made of the tensile properties, impact-, initial fracture toughness and fracture mode of an aluminium-lithium 8090 alloy at room temperature and 77 K, depending upon the heat treatment and orientation. The peak-aged material exhibited an excellent combination of strength and toughness, equal to or exceeding that shown by the high-strength aluminium alloys of the 2000 and 7000 series. The superior strength and toughness of peak-aged plates, including that of 3% stretched material, compared to underaged material seems to be associated with the lower content of coarse insoluble precipitates, a higher density of S-precipitates in a matrix ligament (grain) which promote ductile fracture. The impact toughness of the peak-aged specimens increased at 77 K only in the L-T plate orientation, while in the T-L orientation it was somewhat lower or remained the same. The toughness increase at 77 K is discussed in terms of the role of the matrix and (sub)grain-boundary precipitates, freezing of low-melting point impurities of sodium and potassium alkaline metals at (sub)grain boundaries and the occurrence of the fine crack divider delamination toughening. The yield strength, R _o.2, increase on ageing was accompanied by a corresponding increase in initial crack divider fracture toughness, K _lc, opposite to the trends obtained for some traditional high-strength aluminium alloys. Changes of K _lc versus R _o.2 depending on orientation are discussed using models for ductile fracture toughness behaviour of aluminium alloys, based on the criterion that a critical width of the heavily strained zone at the crack tip approximates the average ligament width, d _p, i.e. the thickness of the elongated grain in the L-T and T-L plate orientations. It was also found that, for constant chemical composition and fabrication practice of the alloy, a critical plate thickness exists B 0.1 6 t _i, where _i is the initial thickness of the rolling ingot, for which the tensile strength properties in the L-T orientation are the same as that in the T-L orientation, while the plasticity (measured by elongation to failure) of the plate is a maximum. Two types of laminated cracks were observed on fracture surfaces of the specimens: large, >1 mm deep (the number of these cracks remains the same as the number of hot-rolling passes), and fine <0.4 mm (shallow laminated cracks, the number of which significantly increases with decreasing temperature, 77 K).     

Structure–Activity Relationship Studies on (R)‐PFI‐2 Analogues as Inhibitors of Histone Lysine Methyltransferase SETD7

SETD7 is a histone H3K4 lysine methyltransferase involved in human gene regulation. Aberrant expression of SETD7 has been associated with various diseases, including cancer. Therefore, SETD7 is considered a good target for the development of new epigenetic drugs. To date, few selective small‐molecule inhibitors have been reported that target SETD7, the most potent being (R)‐PFI‐2. Herein we report structure–activity relationship studies on (R)‐PFI‐2 and its analogues. A library of 29 structural analogues of (R)‐PFI‐2 was synthesized and evaluated for inhibition of recombinantly expressed human SETD7. The key interactions were found to be a salt bridge and a hydrogen bond formed between (R)‐PFI‐2′s NH₂⁺ group and SETD7′s Asp256 and His252 residue, respectively.     

In Vitro Photodynamic Activity of N‐Methylated and N‐Oxidised Tripyridyl Porphyrins with Long Alkyl Chains and Their Inhibitory Activity in Sphingolipid Metabolism

A series of N‐methylated and N‐oxidised tripyridyl porphyrins were synthesised, characterised, and their PDT activity was studied with six cell lines. All the tested porphyrins with a long alkyl chain, except one, were more efficient for PDT than an N‐methylated hydrophilic porphyrin and N‐oxidised porphyrin without the long alkyl chain. Generally, N‐methylated tripyridyl porphyrins were more active than those N‐oxidised, but IC₅₀ values for phototoxicity of two N‐oxides, named TOPyP3‐C₁₇H₃₃O and TOPyP3‐C₁₇H₃₅ , were still in the nanomolar concentration range for most of the tested cell lines. However, TOPyP3‐C₁₇H₃₅ did not show phototoxicity on human foreskin fibroblast cells. Two methylated amphiphilic porphyrins, named TMPyP3‐C₁₇H₃₃ and TMPyP4‐C₁₇H_{35 ,} showed significant dark toxicity, whereas none of the oxidopyridyl porphyrins were toxic without light activation. The selected photosensitisers were shown to be apoptosis inducers, and had inhibitory effects on the clonogenic growth of HCT116 and HeLa cells. All three N‐methylated amphiphilic porphyrins significantly reduced the migratory potential of HCT116 cells. Porphyrins TMPyP3‐C₁₇H₃₅ and TOPyP3‐C₁₇H₃₅ reduced the activity of acid ceramidase, whereas TOPyP3‐C₁₇H₃₃O had a significant inhibitory effect on sphingosine kinase 1 activity in HeLa cells. Compounds with this dual activity were shown to be the most promising photosensitisers, with potential to treat invasive cancers.     

Circuit-based versus full-wave modelling of active microwave circuits

Modern full-wave computational tools enable rigorous simulations of linear parts of complex microwave circuits within minutes, taking into account all physical electromagnetic (EM) phenomena. Non-linear components and other discrete elements of the hybrid microwave circuit are then easily added within the circuit simulator. This combined full-wave and circuit-based analysis is a must in the final stages of the circuit design, although initial designs and optimisations are still faster and more comfortably done completely in the circuit-based environment, which offers real-time solutions at the expense of accuracy. However, due to insufficient information and general lack of specific case studies, practitioners still struggle when choosing an appropriate analysis method, or a component model, because different choices lead to different solutions, often with uncertain accuracy and unexplained discrepancies arising between the simulations and measurements. We here design a reconfigurable power amplifier, as a case study, using both circuit-based solver and a full-wave EM solver. We compare numerical simulations with measurements on the manufactured prototypes, discussing the obtained differences, pointing out the importance of measured parameters de-embedding, appropriate modelling of discrete components and giving specific recipes for good modelling practices.     

Protection of Fe-Cr-Al alloys in sulfidizing environments by means of an α-Al2O3 scale

The sulfur corrosion behavior of ferritic Fe-22.2Cr-5.5Al and Fe-10.2Cr-5.1Al (wt.%) alloys was studied in sulfur vapor and in a 10%H ₂ S -H ₂ (vol. %) atmosphere at 900°C after preoxidation of the alloys at 1000°C in oxygen to form an -Al ₂ O ₃ scale. The immunity time before onset of sulfidation attack to form a layered scale containing chromium and iron sulfides was dependent upon the -Al ₂ O ₃ scale thickness and the nature of the sulfidizing atmosphere. In pure sulfur at low vapor pressure, =8.1×10 ^–5 atm, the sulfide scale initially developed by the diffusion of metal cations through the -Al ₂ O ₃ barrier. On the other hand, the sulfide was nucleated and grew beneath the Al ₂ O ₃ barrier when the alloys were exposed in the H ₂ S -H ₂ atmosphere at =1.5×10 ^–5 atm. It was possible to demonstate by calculations from a gas-oxide-metal model for sulfur adsorption and diffusion in the solid phases that the types of initial sulfidation attack in these atmospheres were determined by sulfur threshold concentrations at the alloy-oxide and oxide-gas interfaces.     

Photoacoustic measurement of internal quantum efficiency and observation of the exciton effect in GaSe with photoacoustic phase spectra

We studied the room temperature photoacoustic spectra of GaSe single crystals in the vicinity of the energy gap. Exciton formation was observed in both amplitude and phase spectra. The thermal source that arises in the illuminated sample because of optical absorption without free-carrier generation was incorporated in the heat diffusion equation in order to extend the theoretical approach of photoacoustic signal generation. We calculated the optical absorption coefficient, which shows the exciton formation, and the electron-hole generation quantum efficiency eta(G) using an extended model from the phase and amplitude photoacoustic spectra, respectively.     

Towards distributed emergency flow prioritization in software-defined networks

Emergency services must be able to transfer data with high priority over different networks. With 5G, slicing concepts at mobile network connections are introduced, allowing operators to divide portions of their network for specific use cases. In addition, Software-Defined Networking (SDN) principles allow to assign different Quality-of-Service (QoS) levels to different network slices. This paper proposes a microservices-based framework, able to run both centralized and distributed, that guarantees the required bandwidth for the emergency flows and maximizes the best-effort flows over the remaining bandwidth based on their priority. The proposed framework consists of an offline linear model, allowing to optimize the problem for a batch of flow requests. For dynamic situations, an online approach is also required in the framework to handle new incoming flows by calculating the path with a shortest path algorithm and utilizing a greedy approach in assigning bandwidth to the intermediate flows. In this article, the linear model is evaluated through simulation, the distributed architecture is evaluated through emulation while the online approach is validated through physical experiments with SDN switches. The results show that the linear model is able to guarantee the resource allocation for the emergency flows while optimizing the best-effort flows with a sub-second execution time. The distributed architecture is able to split up the managed network into different parts, allowing division of work between controllers. As a proof-of-concept, a prototype with Zodiac switches validates the feasibility of the centralized framework.     

Support Vector Machine State Estimation

The power system state estimator based on the support vector machine (SVM) and the weighted least squares (WLS) method is presented in the paper. The WLS provides state estimations necessary for creating SVM model which is then used for state estimation. The developed algorithm was tested on the IEEE systems, and the performance indicators were calculated in order to compare the accuracy of estimation and the measurement error filtering. The results indicate that the proposed hybrid model outperforms the classical WLS-based state estimation in terms of accuracy and improves measurement error filtering in comparison to the classical estimator.