Investigation of kinetics and thermodynamics of DNA hybridization by means of 2-D fluorescence spectroscopy and soft/hard modeling techniques

Reversible hybridization reaction plays a key role in fundamental biological processes, in many laboratory techniques, and also in DNA based sensing devices. Comprehensive investigation of this process is, therefore, essential for the development of more sophisticated applications. Kinetics and thermodynamics of the hybridization reaction, as a second order process, are systematically investigated with the aid of the soft and hard chemometric methods. Labeling two complementary 21 mer DNA single strands with FAM and Texas red fluorophores, enabled recording of the florescence excitation−emission matrices during the experiments which led to three-way data sets. The presence of fluorescence resonance energy transfer in excitation and emission modes and the closure in concentration mode, made the three-way data arrays rank deficient. To acquire primary chemical information, restricted Tucker3 as a soft method was employed. Herein a model-based method, hard restricted trilinear decomposition, is introduced for in depth analysis of rank deficient three-way data sets. By employing proposed hard method, the nonlinear model parameters as well as the correct profiles could be estimated. In addition, a simple constraint is presented to extract chemically reasonable output profiles regarding the core elements of restricted Tucker3 model.     

Reaction of 2‐Alkoxy‐4,5‐diphenyl‐1,3‐oxazin‐6‐one with different alcohols and elucidation of the products

Reaction of 2‐methoxy‐4,5‐diphenyl‐1,3‐oxazin‐6‐one 1a with methanol was studied, and the product of the reaction was determined by spectroscopic data and X‐ray analysis. In addition, a series of (Z)‐alkyl 3‐(alkoxycarbonylamino)‐2,3‐diphenylacrylate 4 was synthesized and characterized. J. Heterocyclic Chem., (2012).     

Erratum to: Synthesis and anticancer activity of some new pyridine derivatives

Research on Chemical Intermediates -     

Synthesis,characterization, molecular modelling and biological activity of 2‐(pyridin‐1‐ium‐1‐yl) acetate and its Cu2+, Pt4+, Pd2+, Au3+ and Nd3+ complexes

A new series of Cu²⁺, Pt⁴⁺, Pd²⁺, Au³⁺ and Nd³⁺ complexes derived from 2‐(pyridin‐1‐ium‐1‐yl) acetate have been synthesized and characterized using elemental analyses, spectral (infrared (IR), UV–visible, mass, ¹³C NMR and ¹H NMR), magnetic and thermal measurements. IR results suggest that the ligand acts in a neutral monodentate fashion in all complexes. Octahedral geometry is proposed for Cu²⁺ and Pt⁴⁺ complexes and square‐planar for Pd²⁺ and Au³⁺ complexes. The bond lengths, bond angles, and HOMO and LUMO were calculated. Superoxide dismutase‐like radical scavenger activity and cytotoxic activity of the isolated complexes on HepG2 liver cancer cells have been screened. Ligand and complexes (Pt⁴⁺ and Nd³⁺) exhibit potent antioxidant activity upon coordination while Cu²⁺ and Au³⁺ complexes do not show superoxide dismutase‐like radical scavenger activity. The cytotoxic activity assay against HepG2 cell line proves that the ligand and its Pt⁴⁺ complex have a high cytotoxic activity, while the other complexes showed no cytotoxic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Scate: A Scalable Time and Energy Aware Actor Task Allocation Algorithm in Wireless Sensor and Actor Networks

In many applications of wireless sensor actor networks (WSANs) that often run in harsh environments, the reduction of completion times of tasks is highly desired. We present a new time‐aware, energy‐aware, and starvation‐free algorithm called Scate for assigning tasks to actors while satisfying the scalability and distribution requirements of WSANs with semi‐automated architecture. The proposed algorithm allows concurrent executions of any mix of small and large tasks and yet prevents probable starvation of tasks. To achieve this, it estimates the completion times of tasks on each available actor and then takes the remaining energies and the current workloads of these actors into account during task assignment to actors. The results of our experiments with a prototyped implementation of Scate show longer network lifetime, shorter makespan of resulting schedules, and more balanced loads on actors compared to when one of the three well‐known task‐scheduling algorithms, namely, the max‐min, min‐min, and opportunistic load balancing algorithms, is used.     

Polyimide-silver nanocomposite containing phosphine oxide moieties in the main chain: Synthesis and properties

<正>New flame-retardant polyimide-silver nanocomposite containing phosphine oxide moiety in the main chain was synthesized by a convenient ultraviolet irradiation technique.A precursor such as AgNO_3 was used as the source of the silver particles.Polyimide 6 as a source of polymer was synthesized by polycondensation reaction of bis(3-aminophenyl) phenyl phosphine oxide 4 with pyromellitic anhydride 5 in the presence of iso-quinoline as base and in m-cresol solution.The resulting composite film was characterized by FTIR spectroscopy,X-ray diffraction(XRD),transmission electron microscopy(TEM),thermogravimetry(TGA) and differential scanning calorimetry(DSC).The average size of the nanometer Ag particles is about 10 nm.The temperature of 5 and 10%weight loss and also the char yield at 600℃of polyimide-silver nanocomposite 6a were higher than the pure PI 6.     

Asphaltene precipitation modeling through ACE reaping of scaling equations

Precipitation and deposition of asphaltene have undesirable effects on the petroleum industry by increasing operational costs due to reduction of well productivity as well as catalyst poisoning.Herein we propose a reliable model for quantitative estimation of asphaltene precipitation.Scaling equation is the most powerful and popular model for accurate prediction of asphaltene precipitated out of solution in crudes without regard to complex nature of asphaltene.We employed a new mathematical-based approach known as alternating conditional expectation(ACE)technique for combining results of different scaling models in order to increase the accuracy of final estimation.Outputs of three well-known scaling equations,including Rassamdana(RE),Hu(HU),and Ashoori(AS),are input to ACE and the final output is produced through a nonlinear combination of scaling equations.The proposed methodology is capable of significantly increasing the precision of final estimation via a divide-andconquer principle in which ACE functions as the combiner.Results indicate the superiority of the proposed method compared with other individual scaling equation models.     

可重复使用的新型催化剂的合成、表征及在绿色条件下催化Suzuki和Heck反应:锚合在磁性纳米多孔的MCM-41上Pd(0)希夫碱络合物

将Pd希夫碱络合物固定在磁性的MCM-41表面上,做为环境友好且可循环使用的新型多相纳米催化剂,并采用红外光谱、振动探针式磁强计、能量散射谱、透射电镜、扫描电镜、热重、电感耦合等离子体发射光谱和X-射线衍射等对其进行了全面的表征.然后将该催化剂用于以PEG为绿色溶剂的一步法Suzuki和Heck合成反应中,均以较高收率得到目标产物.该法主要优点为反应时间短、反应条件绿色友好、操作简便、无需使用有毒的有机溶剂、催化剂使用量低,且底物适用性广.更为重要的是,通过外部磁场即可方便地将催化剂从反应混合物中分离出来,可重复使用数次而活性和稳定性未见明显下降.