Polyaniline-supported acid as an efficient and reusable catalyst for a one-pot synthesis of β-acetamido ketones via a four-component condensation reaction

Polyaniline-supported acid salts such as polyaniline-hydrochloride, polyaniline-sulfate and polyaniline-nitrate were prepared by oxidation of aniline using ammonium persulfate as oxidizing agents. Polyaniline salts were used as catalyst for the preparation of β-acetamido ketones. Polyaniline-sulfate salt was found to be the best catalyst for the preparation of β-acetamido ketones. Present methodology offers several advantages, such as cheaper process, easy synthesis of stable catalyst, simple work-up procedure, and excellent activity with less amount of catalyst and in addition, the catalyst can be easily recovered after completion of the reaction and reusable without affecting its activity.     

Reducing the demands of heating and cooling in Iranian hospitals

A previous study by the authors concluded that the optimal indoor air temperature for satisfying the wide range of occupancy needs in Iranian hospitals falls in a range from 24 °C to 26 °C. Other measures are also needed to achieve thermal comfort at this temperature for all occupants. This study examines, through modelling, a range of passive building fabric techniques in two monitored case study hospitals to examine how we might best achieve this range of indoor air temperatures, and reduce reliance on the heating and cooling systems. Both case study buildings are simulated using HTB2 in their original and modified states. Modifications are limited to changing the fabric of the buildings in the simulated models. The simulations show that it is theoretically possible to reduce the average heating demand in the two buildings to 9% of the original demand by area. Similarly the cooling demand can be reduced in both buildings to 73% of the original demand by area.     

Metal Triflates Incorporated in Mesoporous Catalysts for Green Synthesis of Fine Chemicals

Strong Lewis acid SnTf-MCM-41 and SnTf-UVM-7 catalysts with unimodal and bimodal pore systems were prepared in a two-step synthesis in which the triflic acid (Tf) was incorporated into previously synthesized mesoporous tin-containing silicas. The Sn incorporation inside the pore walls was carried out through the Atrane method. The SnTf-UVM-7 catalysts were prepared by aggregating nanometric mesoporous particles defining a hierarchic textural-type additional pore system. Catalysts with different Si/Sn ratios in the range 21.8–50.8 for SnTf-MCM-41 and 18.4 for SnTf-UVM-7 were found to be efficient catalysts for the acylation of aromatics and heteroaromatics. Under microwave irradiation the reaction was possible even with acetic acid. The selectivity to the desired product (o-hydroxyacetophenone for phenol) or the unfavored three-substituted five ring heterocycles was dramatically increased under these conditions. The process is green, environmentally safe, and heterogeneous.     

Synthesis of tetrazole from α, β—Unsaturated carbonyl fatty acid

Methyl 4-oxo-trans-2-octadecenoate (II), when treated with excess hydrazoic acid in the presence of BF₃-etherate, produced 66% methyl 5-aza-nonadec-trans-2-enoate (4,5-d)-tetrazole (III), 10% methyl 5-aza-nonadec-4-oxo-trans-2-enoate (IV) and 7% pentadecamide (V). Individual products were characterized by spectral and elemental methods.     

Synthesis ofGEM-dibromocyclopropanoid fatty esters using phenyl (tribromomethyl) mercury

Thegem-dibromocyclopropanation of naturally occurring unsaturated hydroxy fatty esters, methyl ricinoleate (I) and methyl isoricinoleate (II), has been undertaken to provide compounds which might have potential utility. Phenyl(tribromomethyl)mercury reacts only with the carbon-carbon double bond of each substrate, leaving the OH group intact. The product, methyl 9,10-dibromomethylene-12-hydroxyoctadecanoate (III) and methyl 12,13-dibromomethylene-9-hydroxyoctadecanoate (IV), obtained from I and II, respectively, were characterized by elemental, infrared (IR) and nuclear magnetic resonance (NMR) analyses.     

Benefits valuation of potable water quality improvement in Malaysia: the case of Kajang Municipality

This article estimates the benefits of potable water quality improvements in Kajang Municipality in the state of Selangor, Malaysia, using the avertive cost method. Households were willing to pay MYR 322 annually to improve potable water quality. This represents about 80% of their average annual water bill. The present value of aggregate benefits over a period of 30 years at various social discount rates ranged from MYR 301 million to MYR 768 million. These estimates can be used as a reference for public investment criteria. The findings suggest that there is merit in an upward revision of water tariffs if they provide improvements in water quality.     

纤维基材料的仿生学研究动向

纤维基技术的应用对仿生学的成功发展呈现出巨大的潜力,因为宇宙成物在生长过程、多毛结构和增强纤维方面具有许多相似性.约七年前,邓肯道夫纺织技术与工艺研究所协同众位生物学家一起开创了仿生学的研发,至今方兴未艾.     

Sufficient LMI stability conditions for Lur’e type systems governed by a control law designed on their Euler approximate model

In this paper, the stability issue of Lur’e systems governed by a control law stabilising their forward Euler approximate model is investigated. More specifically, the considered control law is obtained by exploiting the advantages of a new Lur’e type Lyapunov function with disconnected level sets. This Lyapunov function is adapted to discrete-time Lur’e systems and to the structure of the forward Euler approximate model. The main result consists of linear matrix inequality conditions allowing to guarantee that the continuous-time Lur’e system associated with the proposed digital control law is globally asymptotically stable. The relevance of this approach is illustrated using a numerical example.     

Pre-Coding for MIMO Systems in Frequency-Selective Fading Channels

Multiple input multiple output (MIMO) systems showed good utilization of channel characteristics. In MIMO systems multiple signals are transmitted using multiple antenna system. This provides each receiver the combined signals and hence, array processing techniques helps in reducing the effects of interference among them. In this paper we devise the use of pre-coded MIMO system to reduce the effects of frequency selectivity and hence, enhance the systems capacity and/or reduce the bit error rate. In this technique we introduce a temporal pre-coder on each antenna signal; this creates a deterministic multi-path signals similar to signals received when the channel is multi-path fading channel. The same antenna signal will arrive at each receiver forming orthogonal sub-space and the receiver will be simple add and delay of the received signals. Ant colony optimization is used in this paper to select the best pre-code. Results showed that we can diagonalize the channel matrix and practically eliminate the interference for frequency selective fading channel. Simulation of two transmitting two receiving antennas pre-coded MIMO system showed that the capacity can be doubled.     

Differences in the Relative Abundance of ProBDNF and Mature BDNF in A549 and H1299 Human Lung Cancer Cell Media

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, has been linked to several human malignancies and shown to promote tumorigenesis. The purpose of this study was to explore the relative abundance of pro-brain-derived neurotrophic factor (proBDNF) and mature BDNF (mBDNF) in A549 (p53 wild-type) and H1299 (p53-null) lung cancer cell media. Higher levels of proBDNF were detected in the media of A549 cells than in H1299 cell media. Using inhibitors, we found that the levels of proBDNF and mBDNF in the media are likely regulated by PI3K, AKT, and NFκB. However, the largest change in these levels resulted from MMP2/9 inhibition. Blocking p53 function in A549 cells resulted in increased mBDNF and decreased proBDNF, suggesting a role for p53 in regulating these levels. The ratio of proBDNF/mBDNF was not affected by MMP2 knockdown but increased in the media of both cell lines upon knockdown of MMP9. Downregulation of either MMP2 or MMP9 by siRNA showed that MMP9 siRNA treatment of either A549 or H1299 cells resulted in decreased cell viability and increased apoptosis, an effect diminished upon the same treatment with proBDNF immunodepleted media, suggesting that MMP9 regulates the cytotoxic effects induced by proBDNF in lung cancer cells.