Photochemical Electrocyclic Ring Closure and Leaving Group Expulsion from N-(9-oxothioxanthenyl)Benzothiophene Carboxamides

N-(9-Oxothioxanthenyl)benzothiophene carboxamides bearing leaving groups (LG− = Cl−, PhS−, HS−, PhCH2S−) at the C-3 position of the benzothiophene ring system photochemically cyclize with nearly quantitative release of the leaving group, LG−. The LG− photoexpulsions can be conducted with 390 nm light or with a sunlamp. Solubility in 75% aqueous CH3CN is achieved by introducing a carboxylate group at the C-6 position of the benzothiophene ring. The carboxylate and methyl ester derivatives regiospecifically cyclize at the more hindered C-1 position of the thioxanthone ring. Otherwise, the photocyclization favors the C-3 position of the thioxanthone. Quantum yields for reaction are 0.01–0.04, depending on LG− basicity. Electronic structure calculations for the triplet excited state show that excitation transfer occurs from the thioxanthone to the benzothiophene ring. Subsequent cyclization in the triplet excited state is energetically favourable and initially generates the triplet excited state of the zwitterionic species. Expulsion of LG− is thought to occur once this species converts to the closed shell ground state

A Lightweight Authentication Framework for Wireless Sensor Networks

Wireless Sensor Network (WSN) is emerging as a dominant technology with its applications in areas like agriculture, communication, environment monitoring, and surveillance. The inherited vulnerability and resource-constrained nature of sensor nodes led researchers to propose many lightweight cryptographic protocols for WSN. These sensors are low-cost, low energy, have low processing capability and have low storage restrictions. WSN suffers from many risks because of these unique constraints. This paper proposes a new lightweight security framework for WSNs and covers different lightweight cryptographic schemes for WSN applications. The aim is to provide cryptographic primitives for integrity, confidentiality, and protection from the man-in-the-middle and reply attacks. The work is based solely on symmetric cryptography and it has four phases; Network Initialization, Node Initialization, Nodes Communication, and Node Authentication. This work adopts the Low-Energy Adaptive Clustering Hierarchy (LEACH) framework, which deploys random rotation to distribute the energy among a group of nodes. The probability of attacking in LEACH is higher at cluster head and member nodes. Therefore, data transmission among communicated nodes is encrypted over multiple levels of protection by dynamic session keys to provide a high level of security. In addition, an authentication ticket is provided by a cluster head for each authenticated node to identify another node. The session keys are dynamically generated and updated during the communication to prevent compromising or capturing the keys. Through simulation and evaluation of the system, the results showed less energy consumption and efficient cryptographic primitive were compared with existing scheme

Toxicity induced by Solanapyrone A in Chickpea shoots and its metabolism through Glutathione/Glutathione-S-Transferase system

Solanapyrone A and C were isolated from a Pakistani isolate of Ascochyta rabiei, Pk-1. Two experiments were conducted to investigate the phytotoxic effects of the most potent toxin, solanapyrone A on chickpea cultivars and its subsequent detoxification through glutathion/glutathion-s-transferase(GST) system. When the shoots of cultivars were fed solanapyrone A, symptoms mimicking to Ascochyta blight appeared and extent of manifestation of symptoms varied with the cultivar. In the first experiment, the effect of three different plant ages of 2 cultivars with different levels of resistance to toxin was determined in terms of GST activity unit. GST activity in Balkasar-2000 (a resistant cultivar) increased 1.92 times, 1.72 and 1.65 times in two-week-old seedling, eight-week-old and adult plants (all treated) respectively as compared to their respective controls. In the highly susceptible cultivar, AUG-424, a slight increase (1.14 times) over control was noticed in GST activity at all the three ages. In the second experiment, where shoots of three cultivars were tested against 2 doses of the toxin, an increase in GST activity in Noor-91 (a moderately susceptible cultivar) and AUG-424 was significantly less than resistant cultivar, Balkasar-2000 showing direct relationship between resistance and activity of the enzyme. It may be concluded that it is a reason for difference in response of cultivars to the disease

Fluxon analogues and dark solitons in linearly coupled Bose-Einstein condensates

Two effectively one-dimensional parallel coupled Bose-Einstein condensates in the presence of external potentials are studied. The system is modelled by linearly coupled Gross-Pitaevskii equations. In particular, grey-soliton-like solutions representing analogues of superconducting Josephson fluxons as well as coupled dark solitons are discussed. Theoretical approximations based on variational formulations are derived. It is found that the presence of a magnetic trap can destabilize the fluxon analogues. However, stabilization is possible by controlling the effective linear coupling between the condensates.Comment: 14 pages, 7 figures, The paper is to appear in Journal of Physics

Design optimisation for cold rolled steel beam sections with web and flange stiffeners

This paper presents the analysis and design optimisation of the cold rolled steel sections for flexural strength considering the effect of cold working exerted on the section during the roll forming process. The sections included channel and zed shapes with complex longitudinal web and flange stiffeners. Nonlinear Finite Element (FE) modelling was developed to model the flexural strength of the channel and zed beams and validated against the four-point bending experiments for these sections. The material properties of steel at the section’s flat parts, corners, and stiffener bends were obtained from tensile tests and were incorporated into the FE simulations to account for the true material properties at these regions due to the cold working during the roll forming process. The strength enhancement at the section corners and stiffener bends obtained from tensile tests were also compared with the predicted values from design standards. The section strength was then optimised using FE modelling results based on the Design Of Experiments (DOE) and response surface methodology. Optimal designs for the channel and zed sections with maximum strength in distortional buckling could be obtained while changing the stiffeners’ position, shape, sizes, and considering true material properties at section corners and stiffener bends. It revealed that, for the two sets of channel and zed sections with the depths of 145 mm and 170 mm, the optimal designs provided up to 43% and 39% increase in flexural strength for the channel and zed sections, respectively; however, when the true material properties at the section corner and the stiffener’s bend regions was included, the increase in flexural strength increased up to 50% and 41%, respectively. Including flange stiffeners to the sections with longitudinal web stiffeners generally increased further the section strength. However, the levels of increase were largely dependent on the section depths and material properties

Re-Scaling of Energy in the Stringy Charged Black Hole Solutions using Approximate Symmetries

This paper is devoted to study the energy problem in general relativity using approximate Lie symmetry methods for differential equations. We evaluate second-order approximate symmetries of the geodesic equations for the stringy charged black hole solutions. It is concluded that energy must be re-scaled by some factor in the second-order approximation.Comment: 18 pages, accepted for publication in Canadian J. Physic

Pengembangan Busy Book Untuk Meningkatkan Perkembangan Kognitif Pada Anak Kelompok B

Kualitas perkembangan anak khususnya perkembangan kognitif sangat ditentukan oleh stimulasi yang diperolehnya sejak dini. Anak membutuhkan stimulasi yang tepat yakni melalui bermain ataupun aktivitas yang menyenangkan seperti permainan Busy Book. Penelitian ini dilatarbelakangi oleh kurangnya penggunaan media permainan untuk menstimulasi kemampuan kognitif anak secara maksimal. Jenis penelitian ini adalah penelitian pengembangan atau Research and Development dengan tujuan untuk mengembangkan media permainan Busy Book untuk meningkatkan kemampuan kognitif anak. Metode pengumpulan data adalah observasi, pembagian angket dan dokumentasi dengan teknik analisis kuantitatif deskriptif. Hasil dari penelitian ini adalah terbuatnya media pembeljaran Busy Book dengan penerapan menggunakan media busy book. Media busy book ini dapat meningkatkan kemampuan kognitif anak yang dapat dilihat berdasarkan hasil penelitian tahap pengembangan I berada pada kategori mulai terlaksana dengan skor 48% untuk pelaksanaan permainan dengan kemampuan kognitif sebesar 55%. Pada pengembangan II pelaksanaan permainan Busy Book  meningkat menjadi 61 % dan berada pada kategori terlaksana dengan baik dengan kemampuan kognitif anak sebenar 60% . Dengan demikian dapat disimpulkan bahwa pengembangan media Busy Book dapat meningkatkan kemampuan kognitif anak kelompok B TK Islam Raudhatul Mahabbah

Soil Seed Bank of Two Karst Ecosystems in Bogor, Indonesia: Similarity with the Aboveground Vegeta-tion and Its Restoration Potential

Karst ecosystem in Bogor is currently threatened by mining activities. Restoration of the disturbed karst areas is urgently required. Seed banks are considered as an important potential seed sources for restoration. This study was conducted to quantify the composition and species diversity of the aboveground vegetation and the seed bank. The study determined the correspondence between the seed bank with the aboveground vegetation in relation with ecosystem restoration. Twenty 6 m × 6 m vegetation plots were established. A total of sixty soil samples were taken from the study sites. The seed bank was studied using germination experiment. All plant species in the vegetation plots and seedlings growing from all soil samples were identified and the number was counted to determine the composition, index of diversity, and index of similarity. There were 80 species from 41 families found in the seed bank in Mt. Nyungcung, dominated by Clidemia hirta (Melastomataceae), whereas 50 species from 29 families found in Mt. Kapur with Cecropia peltata (Urticaceae) dominated the site. Diversity index of Mt. Nyungcung and Mt. Kapur seed banks were 2.09 ± 0.21 and 1.78 ± 0.47 respectively. The similarity index between seed bank and the aboveground vegetation in the two study sites were 32.86% and 27.66% respectively. Mt. Nyungcung seed bank was more diverse than Mt. Kapur. The similarity between the seed bank with the aboveground vegetation in the two study sites were low. Further assessment is needed to determine the role of the seed bank of Mt. Nyungcung and Mt. Kapur in the restoration of the ecosystems

No Longer a Complex, Not Yet a Molecule: A Challenging Case of Nitrosyl O-Hydroxide, HOON

N-(9-Oxothioxanthenyl)benzothiophene carboxamides bearing leaving groups (LG− = Cl−, PhS−, HS−, PhCH2S−) at the C-3 position of the benzothiophene ring system photochemically cyclize with nearly quantitative release of the leaving group, LG−. The LG− photoexpulsions can be conducted with 390 nm light or with a sunlamp. Solubility in 75% aqueous CH3CN is achieved by introducing a carboxylate group at the C-6 position of the benzothiophene ring. The carboxylate and methyl ester derivatives regiospecifically cyclize at the more hindered C-1 position of the thioxanthone ring. Otherwise, the photocyclization favors the C-3 position of the thioxanthone. Quantum yields for reaction are 0.01–0.04, depending on LG− basicity. Electronic structure calculations for the triplet excited state show that excitation transfer occurs from the thioxanthone to the benzothiophene ring. Subsequent cyclization in the triplet excited state is energetically favourable and initially generates the triplet excited state of the zwitterionic species. Expulsion of LG− is thought to occur once this species converts to the closed shell ground state