Synthesis and characterization of new fluorinated photoactive polyamides based on xanthene pendant: Evaluation of antibacterial and heavy metal ions removal behavior

A series of novel organosoluble polyamides (PAs) bearing different functional groups such as flexible ether, substituted imidazole, and xanthene rings and electron-withdrawing CF₃ groups were synthesized from diamines and various dicarboxylic acids. The structures of diamines and PAs were fully characterized by elemental analysis, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance spectroscopy. The PAs showed good solubility in aprotic and polar organic solvents, with high thermal stability exhibiting the glass transition temperatures (T_gs) and 10% weight loss temperatures (T₁₀%) in the range of 184–277°C and 410–480°C in N₂ atmosphere, respectively. These polymers showed fluorescence emission upon irradiation with UV light. Diamine compounds and two of synthesized polymers were also screened for antibacterial activity against gram-positive and gram-negative bacteria, and the obtained results for all four combinations showed good inhibition. Extraction capability for heavy metal ions such as Cr³⁺, Pb²⁺, Hg²⁺, Cd²⁺, and Co²⁺ from aqueous solutions was also tested at 25°C and pH 7–8.     

Integrated Routing Algorithms for Provisioning “Sub-Wavelength” Connections in IP-Over-WDM Networks

This work focuses on developing and implementing comprehensive unified constraint-based routing algorithms within the generalized multi-protocol label switching framework (GMPLS) to provision sub-wavelength circuits (low-rate traffic streams). Constraint-based routing is further augmented in this work by dynamically routing both an active and another alternate link/node-disjoint backup path at the same time in order to provision a given connection request. This new integrated approach combines both IP routing and optical resource allocation to setup end-to-end connections.     

Synthesis and characterization of L‐leucine containing chiral vinyl monomer and its polymer,poly(2‐(methacryloyloxyamino)‐4‐methyl pentanoic acid)

A chiral monomer containing L ‐leucine as a pendant group was synthesized from methacryloyl chloride and L ‐leucine in presence of sodium hydroxide at 4 °C. The monomer was polymerized by free radical polymerization in propan‐2‐ol at 60 °C using 2,2′‐azobis isobutyronitrile (AIBN) as an initiator under nitrogen atmosphere. The polymer, poly(2‐(Methacryloyloxyamino)‐4‐methyl pentanoic acid) is thus obtained. The molecular weight of the polymer was determined to be: M_w is 6.9 × 10³ and M_n is 5.6 × 10³. The optical rotation of both chiral monomer and its polymer varies with the solvent polarity. The amplification of optical rotation due to transformation of monomer to polymer is associated with the ordered conformation of chiral monomer unit in the polymeric chain due to some secondary interactions like H‐bonding. The synthesized monomer and polymer exhibit intense Cotton effect at 220 nm. The conformation of the chain segments is sensitive to external stimuli, particularly the pH of the medium. In alkaline medium, the ordered chain conformation is destroyed resulting disordered random coils. The ordered coiling conformation is more firmly present on addition of HCl. The polymer exhibits swelling‐deswelling characteristics with the change of pH of the medium, which is reversible. The Cotton effect decreases linearly with the increase of temperature which is reversible on cooling. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2228–2242, 2009     

Connection Management Protocols for Dynamic Lightpath Provisioning in Future WDM Networks

This paper investigates and compares the performance of two GMPLS-based distributed control and management protocols for dynamic lightpath provisioning in future IP networks. The first protocol is a global information-based link state approach that consists of both an integrated RWA algorithm and a signaling algorithm. Two triggering mechanisms for the LSAs update procedures are considered; one is periodic-based and the other is threshold-based. The second protocol is a local-information based fixed alternate link routing approach where the signaling protocol is closely integrated with the RWA protocols.     

Dynamic provisioning of low-speed unicast/multicast traffic demands in mesh-based WDM optical networks

This paper addresses the problem of dynamically provisioning both low-speed unicast and multicast connection requests in mesh-based wavelength division multiplexing (WDM) optical networks. Several routing/provisioning schemes to dynamically provision both unicast and multicast connection requests are presented. In addition, a constraint-based grooming strategy is devised to utilize the overall network resources as efficiently as possible. Based on this strategy, several different sequential multicast grooming heuristics are first presented. Then, we devise a hybrid grooming approach and combine it with sequential approaches to achieve a grooming scheme that is biased toward serving multicast traffic demands in comparison with all other sequential grooming approaches. To achieve our objective, we decompose the problem into four subproblems: 1) routing problem; 2) light-tree-based logical-topology-design problem; 3) provisioning problem; and 4) traffic-grooming problem. The simulation results of the proposed schemes are compared with each other and with those of conventional nongrooming approaches. To the best of our knowledge, this is the first detailed paper to address and examine the problem of grooming dynamic multicast traffic demands.     

Evolving simple fault-tolerant routing rules using geneticprogramming

A novel approach to solving network routing and restoration problems using the genetic programming (GP) paradigm is presented, in which a single robust and fault-tolerant program is evolved which determines the near-shortest paths through a network subject to link failures     

Robust QoS Control for Single Carrier PMP Mode IEEE 802.16 Systems

The IEEE 802.16 WirelessMAN standard provides a comprehensive quality-of-service (QoS) control structure to enable flow isolation and service differentiation over the common wireless network interface. By specifying a particular set of service parameters, the media access control (MAC) mechanisms defined in the standard are able to offer predefined QoS provisioning on a per-connection basis. However, the design of efficient, flexible, and yet robust MAC scheduling algorithms for such QoS provisioning still remains an open topic. This paper proposes a new QoS control scheme for single-carrier point-to-multipoint mode wireless metropolitan area network (WirelessMAN) systems, which enables the predefined service parameters to control the service provided to each uplink and downlink connection. By MAC-PHY cross-layer resource allocation, the proposed scheme is robust against particular wireless link degradation. Detailed simulation experiments are presented to study the performance and to validate the effectiveness of the proposed QoS control scheme.     

1H-NMR-Based Metabolomics: An Integrated Approach for the Detection of the Adulteration in Chicken,Chevon, Beef and Donkey Meat

Meat is a rich source of energy that provides high-value animal protein, fats, vitamins, minerals and trace amounts of carbohydrates. Globally, different types of meats are consumed to fulfill nutritional requirements. However, the increasing burden on the livestock industry has triggered the mixing of high-price meat species with low-quality/-price meat. This work aimed to differentiate different meat samples on the basis of metabolites. The metabolic difference between various meat samples was investigated through Nuclear Magnetic Resonance spectroscopy coupled with multivariate data analysis approaches like principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA). In total, 37 metabolites were identified in the gluteal muscle tissues of cow, goat, donkey and chicken using ¹H-NMR spectroscopy. PCA was found unable to completely differentiate between meat types, whereas OPLS-DA showed an apparent separation and successfully differentiated samples from all four types of meat. Lactate, creatine, choline, acetate, leucine, isoleucine, valine, formate, carnitine, glutamate, 3-hydroxybutyrate and α-mannose were found as the major discriminating metabolites between white (chicken) and red meat (chevon, beef and donkey). However, inosine, lactate, uracil, carnosine, format, pyruvate, carnitine, creatine and acetate were found responsible for differentiating chevon, beef and donkey meat. The relative quantification of differentiating metabolites was performed using one-way ANOVA and Tukey test. Our results showed that NMR-based metabolomics is a powerful tool for the identification of novel signatures (potential biomarkers) to characterize meats from different sources and could potentially be used for quality control purposes in order to differentiate different meat types.     

Preparation and characterization of novel thermostable polyamides bearing different photoactive pendent architectures with antibacterial properties

Three diamine monomers with different derivatives of imidazole heterocyclic ring, aryl ethers and electron withdrawing trifluoromethyl groups in the backbone were synthesized and used in polycodensation reaction with various aliphatic and aromatic dicarboxylic acids for preparation of a series of novel polyamides(PAs). The PAs were obtained in high yields and possessed inherent viscosities in the range of 0.26-0.75 d L/g. All of the polymers were amorphous in nature,showed outstanding solubility and could be easily dissolved in amide-type polar aprotic solvents. They showed good thermal stability with glass transition temperatures between 162-302 ℃. Thermogravimetric analysis showed that all polymers were stable, with 10% weight loss recorded above 421 ℃ in N_2 atmospheres. All the PAs presented fluorescence upon irradiation with ultraviolet light and thus showed promise for applications in electroluminescent devices. The monomers and PAs were also screened for antibacterial activity against Gram positive and Gram negative bacteria.