A Search for Good Pseudo-random Number Generators : Survey and Empirical Studies

In today's world, several applications demand numbers which appear random but are generated by a background algorithm; that is, pseudo-random numbers. Since late $19^{th}$ century, researchers have been working on pseudo-random number generators (PRNGs). Several PRNGs continue to develop, each one demanding to be better than the previous ones. In this scenario, this paper targets to verify the claim of so-called good generators and rank the existing generators based on strong empirical tests in same platforms. To do this, the genre of PRNGs developed so far has been explored and classified into three groups -- linear congruential generator based, linear feedback shift register based and cellular automata based. From each group, well-known generators have been chosen for empirical testing. Two types of empirical testing has been done on each PRNG -- blind statistical tests with Diehard battery of tests, TestU01 library and NIST statistical test-suite and graphical tests (lattice test and space-time diagram test). Finally, the selected $29$ PRNGs are divided into $24$ groups and are ranked according to their overall performance in all empirical tests

Reversibility of Affine Transformations

Let $\mathbb{D}:=\mathbb{R}, \mathbb{C}$ or $\mathbb{H}$. In this paper, we have classified reversible and strongly reversible elements in the affine group $\mathrm{GL}(n, \mathbb{D}) \ltimes \mathbb{D}^n$. Our primary approach is based on the notion of an infinitesimal version of the classical reversibility, namely adjoint reality in the Lie algebra set-up. Using this new approach, we also revisit such classification for the group $\mathrm{GL}(n, \mathbb{D})$. This extends understanding of reversibility for $\mathrm{GL}(n, \mathbb{H})$ and gives new proofs for the general linear groups over $\mathbb{R}$ and $\mathbb{C}$. Further, we have investigated reversing symmetry groups in $\mathrm{GL}(n, \mathbb{D})$.Comment: 24 page

Quantum chaos in the spectrum of operators used in Shor's algorithm

We provide compelling evidence for the presence of quantum chaos in the unitary part of Shor's factoring algorithm. In particular we analyze the spectrum of this part after proper desymmetrization and show that the fluctuations of the eigenangles as well as the distribution of the eigenvector components follow the CUE ensemble of random matrices, of relevance to quantized chaotic systems that violate time-reversal symmetry. However, as the algorithm tracks the evolution of a single state, it is possible to employ other operators, in particular it is possible that the generic quantum chaos found above becomes of a nongeneric kind such as is found in the quantum cat maps, and in toy models of the quantum bakers map.Comment: Title and paper modified to include interesting additional possibilities. Principal results unaffected. Accepted for publication in Phys. Rev. E as Rapid Com

Understanding the Interactions of Anions with Lewis Acids and π-Acids to Develop Efficient Ion-Pair Receptors

Anions play vital roles in many industrial, environmental, chemical, and biological processes. Due to their adverse effects on our health and ecosystem, precise regulation of toxic anions and ion-pairs are of prime importance. A majority of anion receptors rely on subtle supramolecular forces like electrostatic interactions and hydrogen bonding to bind anions, and the main source of selectivity comes from the shape and size complementarity of the receptors and guest anions. In aprotic solvents, interactions of anions with π-acidic receptors such as naphthalenediimides (NDIs) and perylenediimides (PDIs), and Lewis acids, such as silver ion, depend on their electron donating ability, which runs parallel to their Lewis basicity. While non-basic larger charge-diffuse anions engage in anion–π and CH···anion interactions in aprotic solvents, stronger Lewis basic and less solvated hard anions participate in electron transfer (ET) and weaker Lewis basic anions establish charge transfer (CT) interactions. The anion-induced electron transfer from strong Lewis basic anions produces colorful radical anions and dianions of π-acids leading to colorimetric anion sensing. Anion-induced electron transfer (AIET) is not only limited to π-acids. Reduction of silver(I) to produce silver(0) mirrors and luminescent silver(0) nanoparticles show that AIET can happen from fluoride to a Lewis acid, too. On the other hand, NDI-imine-based heteroditopic ion-pair receptors are developed to capture both cations and charge diffuse anions, cooperatively. These synthetic receptors exploited anion–π and CH···anion interactions to bind anions cooperatively in the presence of metal ions such as Zn(II) and Cd(II)

Tunica vaginalis flap – is it a better surgical choice for urethro-cutaneous fistula following circumcision?

Objective: To study the effectiveness of tunica vaginalis flap in repair of post circumcision urethro- cutaneous fistula. Materials and Methods: The current study reviewed all patients having surgical repair of post-circumcision urethrocutaneous fistula from December 2014 to April 2019 at our institution. Results: Ten cases presenting at age 5 to 22 years were operated. Most [60%] of the circumcisions were performed by a doctor at peripheral hospitals and others were done by traditional circumcisers. All cases had a single fistula and the size was more than 5mm in all cases. Three-layered fistula closure was done in all cases using the tunica vaginalis flap as the second layer for closure. There was no recurrence in any case. Conclusion: Use of Tunica vaginalis flap for repair of post circumcision urethro-cutaneous fistula is a highly effective technique regardless of size and site of the fistula. It is a simple procedure without any postoperative complications and without any recurrenc

Effect of melatonin on secreted and induced matrix metalloproteinase-9 and -2 activity during prevention of indomethacin-induced gastric ulcer

Matrix metalloproteinases (MMPs) maintain the crucial role in physiological turnover of extracellular matrix (ECM) proteins in gastric tissues. However, a little is known about the relationship of MMPs with ECM degradation during gastric ulceration and ECM remodeling during healing. Our objective was to investigate the effect of melatonin (N-acetyl-5 methoxytryptamine) on the regulation of MMP-9 and MMP-2 activity during prevention of gastric ulcer. In the present study, biochemical and zymographic methods were used to analyze the mechanism of melatonin in indomethacin-induced gastric ulcer in a rat model. Our studies reveal that melatonin dose-dependently downregulates the expression and secretion of pro-MMP-9 which is induced (approximately 10-fold) during indomethacininduced gastric ulceration. Furthermore, melatonin prevents gastric ulceration in a dose-dependent manner through upregulation (approximately two- to threefold) of both pro-MMP-2 and active MMP-2 at the level of induction as well as secretion. It also prevents gastric ulcers by blocking glutathione depletion and lipid peroxidation in cytosolic and microsomal fractions. The novel findings of this study are attributed to the attenuation of the pro-MMP-9 and increase of MMP-2 activity by pretreatment with melatonin. The finding defines one of the MMP-mediated pathways for melatonin’s action in gastric ulcer

GREEN SYNTHESIS OF SILVER NANOPARTICLES USING MANGROVE FRUIT POLYSACCHARIDE FOR BACTERIAL GROWTH INHIBITION: GREEN SYNTHESIS OF SILVER NANOPARTICLES

Objective: The objective of this study was to find out the antibacterial activity of the silver nanoparticles (Ag-NPs) using a low-cost green synthesis approach for the formulation of Ag-NPs applying polysaccharide extracted from the fruits of a mangrove plant of Sundarban. Methods: Fresh and healthy fruits were collected from Ceriops decandra plant. Sufficient amount of carbohydrates was extracted from those fruits and the physicochemical characterization of the polysaccharide was analyzed by gas chromatography–mass spectrometry and Fourier-transform infrared spectrophotometry. The respective polysaccharide was further applied to generate the Ag-NPs which were characterized by UV visible, dynamic light scattering, transmission electron microscopy, EDAX, and X-ray diffraction. The antibacterial efficacy of the Ag-NPs was also determined against some pathogenic Gram-negative and Gram-positive bacteria using the microdilution method. Results: Glucose and galactose are the major monomers among the extracted carbohydrates. Various types of spectral analysis confirmed the formation of Ag-NPs. The green synthesized Ag-NPs have the average diameter of about 28 nm. Furthermore, the green synthesized Ag-NPs exhibited strong antibacterial activity against some pathogenic Gram-positive (L. cytomonogenes, Bacillus Subtilis, and Staphylococcus aureus) and Gram-negative (Salmonella typhimurium and Escherichia coli) bacteria. Conclusion: The green synthesis of Ag-NPs using plant polysaccharide was an environment-friendly and cost-effective method as compared to the conventional physical and chemical synthesis techniques

CCDC 1881920: Experimental Crystal Structure Determination

Related Article: Dillip K. Panda, Krishnendu Maity, Andrei Palukoshka, Faysal Ibrahim, Sourav Saha|2019|ACS Sustain.Chem.Eng.|7|4619|doi:10.1021/acssuschemeng.8b0625