Sampling Conformation Space to Model Equilibrium Fluctuations in Proteins

This paper proposes the Protein Ensemble Method (PEM) to model equilibrium fluctuations in proteins where fragments of the protein polypeptide chain can move independently of one another. PEM models global equilibrium fluctuations of a polypeptide chain by combining local fluctuations of consecutive overlapping fragments of the chain. Local fluctuations are computed by a probabilistic exploration that exploits analogies between proteins and robots. All generated conformations are subjected to energy minimization and then are weighted according to a Boltzmann distribution. Using the theory of statistical mechanics the Boltzmann-weighted fluctuations corresponding to each fragment are combined to obtain fluctuations for the entire protein. The agreement obtained between PEM-modeled fluctuations, wet-lab experiment and guided simulation measurements, indicates that PEM is able to reproduce with high accuracy protein equilibrium fluctuations that occur over a broad range of timescales.     

Synthesis of Dimer Acid 2-Ethylhexyl Esters and their Physicochemical Properties as Biolubricant Base Stock and their Potential as Additive in Commercial Base Oils

Previously synthesized C36-dimer acids (DA) have been esterified (97 ± 0.2% conversion at 120 °C for 72 hours) with 2-ethylhexanol (2-EH) to produce a new class of C52-DA 2-EH esters that have potential application in biolubricant formulations such as base oils and additives. Investigation of physicochemical and lubricant properties showed the bio-based esters have good solubility in commercial base stocks such as polyalpha olefin (PAO-6) (>20 w/w) and high-oleic sunflower oil (HOSuO) (>20 w/w). The neat C52-DA 2-EH esters displayed a three- to eightfold higher kinematic viscosity and comparable viscosity index (VI = 134) as a commercial base stock, PAO-6 (VI =137). Both C52-DA 2-EH esters, whose parent C36-DA were synthesized with two different zeolite catalysts, were oxidatively stable above 176 °C. Blending C52-DA 2-EH esters in HOSuO improved the pour point (PP) of HOSuO from −18.8 to −21.0 °C at 1% w/w and the cloud point (CP) from −6.3 to −10.6 °C at 8% w/w of C52-DA 2-EH ester 1. A similar trend was observed for C52-DA 2-EH ester 2, indicating that the esters possess PP depressant (PPD) characteristics in HOSuO blends. Blending C52-DA 2-EH esters in PAO-6 increased the VI of PAO-6, which is an indication that the bio-based esters were acting as VI improvers (VII). It was concluded that C52-DA 2-EH esters can be employed commercially as bio-based base oils and as PPD and VII additives in lubricant formulations.     

Note: Fire-retardant treatment of roofing thatch

The double salt calcium phosphate–calcium sulphate monohydrate, hereafter referred to as fertilizer, was used to impregnate some grass commonly used for roofing houses. It was found that this treatment significantly changed the thermal characteristics of the material. Reasons are adduced to explain these observations.     

A high-vacuum deposition system for in situ and real-time electrical characterization of organic thin-film transistors

We present a home-built high-vacuum system for performing organic semiconductor thin-film growth and its electrical characterization during deposition (real-time) or after deposition (in situ). Since the environment conditions remain unchanged during the deposition and electrical characterization process, a direct correlation between growth mode and electrical properties of thin film can be obtained. Deposition rate and substrate temperature can be systematically set in the range 0.1-10 ML∕min and RT-150 °C, respectively. The sample-holder configuration allows the simultaneous electrical monitoring of up to five organic thin-film transistors (OTFTs). The OTFTs parameters such as charge carrier mobility μ, threshold voltage V(TH), and the on-off ratio I(on)∕I(off) are studied as a function of the semiconductor thickness, with a submonolayer accuracy. Design, operation, and performance of the setup are detailed. As an example, the in situ and real-time electrical characterization of pentacene TFTs is reported.     

Spoken character classification using abductive network

In this paper, we address the problem of learning a classifier for the classification of spoken character. We present a solution based on Group Method of Data Handling (GMDH) learning paradigm for the development of a robust abductive network classifier. We improve the reliability of the classification process by introducing the concept of multiple abductive network classifier system. We evaluate the performance of the proposed classifier using three different speech datasets including spoken Arabic digit, spoken English letter, and spoken Pashto digit. The performance of the proposed classifier surpasses that reported in the literature for other classification techniques on the same speech datasets.     

Synthesis of hierarchical nanoporous HY zeolites from activated kaolin,a central composite design optimization study

In this article, we investigated the optimum formulation towards synthesis of hierarchical nanoporous HY zeolites from acid activate kaolin. A central composite design (CCD) helped to examine the influence of aging (X₁), crystallization (X₂) and NaOH solution to kaolin ratio (X₃) on crystallinity (C%), specific surface area (SSA) and hierarchical factor (HF). From the analysis of variance (ANOVA), we deduced that all the process variables show statistical significance towards obtaining high C% and SSA while only X₃ is statistically significant for optimal HF. The effectiveness of models was further evaluated using margin of error and tolerance interval. The Optimum formulation for this hierarchical nanoporous HY zeolite was 43.60, 64.23 and 6.97 for X₁, X₂, and X₃, respectively. The developed models show that X₃ is the most statistically significant variable because it has the highest coefficient and the lowest p-value in the entire model. These results give instrumental insight into the synthesis of hierarchical nonporous HY zeolite.     

Major challenges to the successful implementation and practice of programme management in the construction environment: A critical analysis

For the construction industry to survive the current turbulence in the economic atmosphere, it has the option of integrating new initiatives to march the uncertainties. Programme management is seen as an efficient vehicle to successfully deliver the improvements and changes. However, the implementation of any new system or change initiatives has always been a challenging task; some of these challenges can be faced during the implementation or at practice stage. Programme management is not exempt from such challenges, in order to successfully implement and practice programme management, the knowledge of the major challenges associated to effective implementation and practice should not be left to serendipity or sagacity. Due to the lack of clarity surrounding programme management in the construction industry, the understanding of these major challenges remains vague. To provide a deeper insight into the major challenges to implementation and practice of construction programme management, this paper conducts both a pragmatic and theoretical study by triangulating literature, industrial questionnaire survey and semi-structured interviews. The research was conducted in the UK construction industry and other programme management sectors to analyse and exploit the knowledge of these challenges for effective implementation and practice of construction programmes. A total of 119 usable questionnaires were received and 17 semi-structured interviews were conducted, analysed and synthesised to provide a broader view on the major challenges and how to effectively implement and practice construction programmes.     

NASARA-I WELL, GONGOLA BASIN (UPPER BENUE TROUGH, NIGERIA): SOURCE-ROCK EVALUATION

Well Nasara‐I, one of three exploration wells recently drilled in the Gongola Basin in the Upper Benue Trough (onshore Nigeria), was tested and found to be dry. The well penetrated an entirely Cretaceous succession comprising the Pindiga, Yolde and? Bima Formations, and standard organic geochemical analyses were carried out to assess the source‐rock potential of selected samples. Total organic carbon (TOC) contents were found generally to be very low, with no values exceeding 1.0wt%, and about one‐half of them ranging between 0.50 and 0.87wt%. Hydrogen indices (Hls) correlated against Tmax indicate some gas‐generative potential. However, in the depth interval between 4,710ft and 4,770ft, TOC values of between 52.1 and 55.2 wt% were recorded; these are characteristic of coals. This is the first report of a coal within the Pindiga, Yolde or Bima Formations. Hls were between 564 and 589 mgHC/gTOC and Tmax was 423–428°C. Although hydrogen indices can be misleading in assessing the oil‐generative potential of a coal, values as high as those recorded in Nasara‐I permit oil‐generative capabilities to be inferred. Total ion chromatograms of the saturated hydrocarbon fractions of the coaly samples show some ramping of unresolved complex mixtures attributable to biodegradation. Further biomarker data indicate a dominance of low molecular weight n‐alkanes (C₁₅–C₂₅), pristane/phytane ratios of 0.8 to 1.3, and very high contents of C₂₈ regular steranes. These attributes, together with the very high Hls, indicate that some oils generated from a probably deeper‐seated or laterally‐located (and yet to be identified) lacustrine source rock must have migrated and been adsorbed into the coaly facies, which were later intermittently subjected to anoxic to suboxic biodegradation processes.