A comparison of two algorithms for the assignment problem

State-of-the-art computational results have shown that the shortest augmenting path (SAP) methods are more efficient than other primal-dual and primal-simplex based methods for solving the linear assignment problem on uniprocessor computers. There is, however, some controversy concerning their merits when compared with Bertsekas' auction algorithm on multiprocessor computers. In this study we investigate the performance of these competing methods on the Alliant FX/8. For each method, theoretical motivation, sources of parallelism and computational results are presented.     

Lie-group method solution for two-dimensional viscous flow between slowly expanding or contracting walls with weak permeability

The non-linear equations of motion describing the laminar, isothermal and incompressible flow in a rectangular domain bounded by two weakly permeable, moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions, are considered. We apply Lie-group method for determining symmetry reductions of partial differential equations. Lie-group method starts out with a general infinitesimal group of transformations under which given partial differential equations are invariant, then, the determining equations are derived. The determining equations are a set of linear differential equations, the solution of which gives the infinitesimals of the dependent and independent variables. After the group has been determined, a solution to the given partial differential equation may be found from the invariant surface condition such that its solution leads to similarity variables that reduce the number of independent variables in the system. Effect of the permeation Reynolds number R_e and the dimensionless wall dilation rate α on self-axial velocity have been studied both analytically and numerically and the results are plotted.     

Drug–Membrane Interaction on Immobilized Liposome Chromatography Compared to Immobilized Artificial Membrane (IAM), Liposome/Water,and Octan‐1‐ol/Water Systems

The objective of this study was to investigate drug–membrane interaction by immobilized liposome chromatography (ILC; expressed as lipophilicity index log K_s) and the comparison with lipophilicity indices obtained by liposome/H₂O, octan‐1‐ol/H₂O, and immobilized artificial membrane (IAM) systems. A set of structurally diverse monofunctional compounds and drugs (nonsteroidal anti‐inflammatory drugs and β‐blockers) were selected in this study. This set of solutes consists of basic or acidic functionalities which are positively or negatively charged at physiological pH 7.4. No correlation was found between log K_s from ILC and lipophilicity indices from any of the other membrane model systems for the whole set of compounds. For structurally related compounds, significant correlations could be established between log K_s from ILC and lipophilicity indices from IAM chromatography and octan‐1‐ol/H₂O. However, ILC and liposome/H₂O systems only yield parallel partitioning information for structurally related large molecules. For hydrophilic compounds, the balance between electrostatic and hydrophobic interactions dominating drug partitioning is different in these two systems.     

Synthesis of Some Novel Imidazopyrazole and Pyrazolopyrimidine Derivatives

5‐Amino‐3‐anilino‐1H‐pyrazole‐4‐carbonitrile 1 was alkylated with various halo reagents under phase transfer conditions to give the corresponding imidazopyrazole derivatives 2a , 2b , 2c , 3 , 4 , 5 , 6 . Pyrazolo[1,5‐a] pyrimidine derivatives 11 , 12 , 13 , 14 were prepared by treating compound 1 with different dicarbonyl reagents, namely, diethymalonate, ethyl 3‐oxo‐3‐phenylpropanoate, pentane‐2,4‐dione or ethyl 3‐oxobutanoate.     

All optical Flip-Flop based on a nonlinear DFB semiconductor laser: Theoretical study

A new design of an all optical Flip-Flop is proposed. It consists of a nonlinear distributed feedback (DFB) laser. The wave guiding layer of the DFB laser consists of linear grating section followed by a nonlinear one, and both sections are separated by a phase shift section. In the OFF-state, the real part of the refractive index in the wave guiding layer forms a Bragg grating. In the ON-state, it forms a Bragg grating with a phase shift section. Optical gain is achieved by current injection in the semiconductor active layer. Nonlinearity in the nonlinear layers of the semiconductor grating was achieved by direct absorption at the edge of the absorption band (Urbach tail). Numerical simulation shows that the device switches in a nanosecond time scale.     

Compression Helps Deep Learning in Image Classification

The impact of JPEG compression on deep learning (DL) in image classification is revisited. Given an underlying deep neural network (DNN) pre-trained with pristine ImageNet images, it is demonstrated that, if, for any original image, one can select, among its many JPEG compressed versions including its original version, a suitable version as an input to the underlying DNN, then the classification accuracy of the underlying DNN can be improved significantly while the size in bits of the selected input is, on average, reduced dramatically in comparison with the original image. This is in contrast to the conventional understanding that JPEG compression generally degrades the classification accuracy of DL. Specifically, for each original image, consider its 10 JPEG compressed versions with their quality factor (QF) values from {100,90,80,70,60,50,40,30,20,10}. Under the assumption that the ground truth label of the original image is known at the time of selecting an input, but unknown to the underlying DNN, we present a selector called Highest Rank Selector (HRS). It is shown that HRS is optimal in the sense of achieving the highest Top k accuracy on any set of images for any k among all possible selectors. When the underlying DNN is Inception V3 or ResNet-50 V2, HRS improves, on average, the Top 1 classification accuracy and Top 5 classification accuracy on the whole ImageNet validation dataset by 5.6% and 1.9%, respectively, while reducing the input size in bits dramatically—the compression ratio (CR) between the size of the original images and the size of the selected input images by HRS is 8 for the whole ImageNet validation dataset. When the ground truth label of the original image is unknown at the time of selection, we further propose a new convolutional neural network (CNN) topology which is based on the underlying DNN and takes the original image and its 10 JPEG compressed versions as 11 parallel inputs. It is demonstrated that the proposed new CNN topology, even when partially trained, can consistently improve the Top 1 accuracy of Inception V3 and ResNet-50 V2 by approximately 0.4% and the Top 5 accuracy of Inception V3 and ResNet-50 V2 by 0.32% and 0.2%, respectively. Other selectors without the knowledge of the ground truth label of the original image are also presented. They maintain the Top 1 accuracy, the Top 5 accuracy, or the Top 1 and Top 5 accuracy of the underlying DNN, while achieving CRs of 8.8, 3.3, and 3.1, respectively.     

Mangostanaxanthone VIII,a new xanthone from Garcinia mangostana and its cytotoxic activity

A new prenylated xanthone, mangostanaxanthone VIII (7) and six known metabolites: gartanin (1), 1,3,8-trihydroxy-2-(3-methyl-2-butenyl)-4-(3-hydroxy-3-methylbutanoyl)-xanthone (2), rubraxanthone (3), 1,3,6,7-tetrahydroxy-8-prenylxanthone (4), garcinone C (5), and xanthone I (9-hydroxycalabaxanthone) (6) were separated from the EtOAc-soluble fraction of the air-dried pericarps of Garcinia mangostana (Clusiaceae). Their structures have been verified on the basis of spectroscopic data analysis as well as comparison with the literature. The cytotoxic activity of 7 was assessed against MCF7, A549, and HCT116 cell lines using sulforhodamine B (SRB) assay. Compound 7 showed significant cytotoxic potential against MCF7 and A549 cell lines with IC₅₀s 3.01 and 1.96 μM, respectively compared to doxorubicin (0.06 and 0.44 μM, respectively). However, it exhibited moderate activity towards HCT116 cell line.     

Eco-friendly solvent-free synthesis of thiazolylpyrazole derivatives

Highly versatile ethyl 3-thiosemicarbazidobutanoate was ball-milled with phenacyl bromide to afford the corresponding ethyl 3-[(4-phenyl-2-thiazolyl)hydrazono]butanoate which underwent heterocyclization by heating in ethanolic sodium acetate to give thiazolylpyrazolone that coupled chemoselectively with aromatic diazonium salts to furnish arylhydrazonothiazolylpyrazoles. Vilsmeier-Haack reaction of ethyl 3-thiosemicarbazidobutanoate furnished selectively thiazolylpyrazole. A series of pyrazolylthiosemicarbazones were synthesized by solid-state technique which allowed waste-free production. The reaction of pyrazolylthiosemicarbazones with phenacyl bromide afforded the corresponding 2-(arylidenehydrazino)-4-phenylthiazoles in quantitative yields. Correspondence: Samir Bondock, Department of Chemistry, Faculty of Science, Mansoura University, ET-31556 Mansoura, Egypt.     

Electrical characteristics and chemical stability of non-oxidized, methyl-terminated silicon nanowires

Silicon nanowires (Si NWs) modified by covalent Si-CH3 functionality, with no intervening oxide, show atmospheric stability, high conductance values, low surface defect levels, and allow for the formation of air-stable Si NW Field-Effect Transistors (FETs) having on-off ratios in excess of 105 over a relatively small gate voltage swing (+/-2 V).     

New Ni(II), Pd(II) and Pt(II) complexes coordinated to azo pyrazolone ligand with a potent anti‐tumor activity: Synthesis,characterization, DFT and DNA cleavage studies

The absolute necessity to fight some class of tumor is perceived as serious health concerns, so the discovery and development of effective anticancer agents are urgently needed. (E)‐4‐((2‐hydroxyphenyl)diazenyl)‐3‐phenyl‐1H‐pyrazol‐5(4H)‐one, HL, and its Ni(II), Pd(II) and Pt(II) complexes were synthesized and the biological activity was evaluated for antitumor, antioxidant and antimicrobial activity as well as DNA cleavage. Their structures were assigned depending on the elemental analysis, conductivity, magnetic moment, spectral measurements (IR, ¹HNMR, mass and UV–Vis) and thermal analysis. 3D molecular modeling using DFT method confirmed that the geometrical structures agree well with the suggested experimental ones. The antitumor activity was evaluated against four different cell lines using MTT assay. The ligand HL showed a potent cytotoxic activity compared to 5‐fluorouracil as a reference drug. For metal complexes, the order of activity was: Pd(II) > Ni(II) > Pt(II). A remarkable antioxidant activity for the ligand HL was recorded. It was higher than that of the metal complexes. Results of antimicrobial experiments revealed that all compounds were moderate to highly active against selected bacterial strains but inactive as antifungal except Pd(II) which showed a moderate antifungal activity. Gel electrophoresis showed insignificant nucleases activity for the ligand or its metal complexes even in the presence of H₂O₂ providing protection of DNA from damage. The antitumor activity of our compounds may be not due to DNA cleavage but may be referred to a mechanism similar to that of 5‐fluorouracil which interfere with DNA replication. The present work suggests the use of this ligand in the design and development of new anticancer drugs.