Synthesis of DNA-Encoded Disulfide- and Thioether-Cyclized Peptides

DNA-encoded chemical library technologies enable the screening of large combinatorial libraries of chemically and structurally diverse molecules, including short cyclic peptides. A challenge in the combinatorial synthesis of cyclic peptides is the final step, the cyclization of linear peptides that typically suffers from incomplete reactions and large variability between substrates. Several efficient peptide cyclization strategies rely on the modification of thiol groups, such as the formation of disulfide or thioether bonds between cysteines. In this work, we established a strategy and reaction conditions for the efficient chemical synthesis of cyclic peptide–DNA conjugates based on linking the side chains of cysteines. We tested two different thiol-protecting groups and found that tert-butylthio (S-tBu) works best for incorporating a pair of cysteines, and we show that the DNA-linked peptides can be efficiently cyclized through disulfide and thioether bond formation. In combination with established procedures for DNA encoding, the strategy for incorporation of cysteines may be readily applied for the generation and screening of disulfide- and thioether-cyclized peptide libraries.     

Catalytic Combustion of Model Carbon Particles (CPs) over Pt/β-SiC Catalyst

Platinum catalyst supported on a medium surface area -SiC was successfully used for the catalytic combustion of model carbon particles and compared to a catalyst supported on a low surface area -SiC. The -SiC-based catalyst showed no deactivation as a function of cycling tests while a strong deactivation was observed on the -SiC-based catalyst. This deactivation was attributed to the progressive encapsulation of the platinum particles by a layer of silica which built up during the combustion cycle. These results render possible the use of Pt/-SiC catalyst as a diesel carbon particle catalytic filter with continuous regeneration.     

Engineering of Self-Assembled Fibronectin Matrix Protein and Its Effects on Mesenchymal Stem Cells

Fibronectin (FN) contributes to cell adhesion, proliferation, and differentiation in various cell types. To enhance the activity of fibronectin at the sites of focal adhesion, we engineered a novel recombinant fibronectin (FNIII10) fragment connected to the peptide amphiphile sequence (PA), LLLLLLCCCGGDS. In this study, the effects of FNIII10-PA on rat mesenchymal stem cells (rMSCs) were compared with those of FNIII10. FNIII10-PA showed the prominent protein adhesion activity. In addition, FNIII10-PA showed a significantly higher effect on adhesion, proliferation, and differentiation of rMSCs than FNIII10. Taken together, the FNIII10-containing self-assembled sequence enhanced rMSCs adhesion, proliferation, and differentiation.     

Low complexity probability-based piecewise linear approximation of the sigmoid function

In order to improve the network recognition accuracy in the low complexity condition, a piecewise linear sigmoid function approximation based on the distribution probability of the neurons’ values is proposed only with one addition circuit. The sigmoid function is first divided into three fixed regions. Second, according to the neurons’ values distribution probability, the curve in each region is segmented into sub-regions to reduce the approximation error and improve the recognition accuracy. The slope of the piecewise linear function is set as 2-n, effectively reducing the hardware implementation complexity. Experiments performed on Xilinx’s FPGA-XC7A200T implement the MNIST handwritten digits recognition. The results show that the proposed method achieves a 97.45% recognition accuracy in a deep neural network and 98.42% in a convolutional neural network, up to 0.84% and 0.57% higher than other approximation methods only with one addition circuit.     

Process synthesis and optimization of biorefinery configurations

Recently, there has been a growing interest in the development of cost‐effective technologies for the production of biofuels. A common approach to biofuel research is to invent or improve a biochemical or thermochemical conversion step. Subsequently, other conversion and separation steps are added to form a complete biorefinery flowsheet. Because this approach is structured around a specific conversion step, it may limit the possibilities of configuring optimal and innovative biorefineries. This article proposes a novel and systematic two‐stage approach to the synthesis and optimization of biorefinery configurations, given available feedstocks and desired products. In the synthesis stage, a systems‐based approach is developed to create a methodical way for synthesizing integrated biorefineries. This method is referred to as “forward‐backward” approach. It involves forward synthesis of biomass to possible intermediates and reverse synthesis starting with the desired products and identifying necessary species and pathways leading to them. In the optimization stage, Bellman's principle of optimality is applied to decompose the optimization problem into subproblems in which an optimal policy of available technologies is determined for every conversion step. An optimization formulation is utilized to determine the optimal configuration based on screening and connecting the optimal policies and generating the biorefinery flowsheet. A case study of alcohol‐producing pathways from lignocellulosic biomass is solved to demonstrate the merits of the proposed approach. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Blind separation of instantaneous mixture of sources based on orderstatistics

In this paper, we introduce a novel procedure for separating an instantaneous mixture of sources based on order statistics. The method is derived in a general context of independence component analysis, using a contrast function defined in term of the Kullback-Leibler divergence or of the mutual information. We introduce a discretized form of this contrast permitting its easy estimation through order statistics. We show that the local contrast property is preserved and derive a global contrast, exploiting only the information of the support of the distribution (in case this support is finite). Some simulations are given, illustrating the good performance of the method     

The emergence of coherence over the course of decision making.

Previous research has indicated that decision making is accompanied by an increase in the coherence of assessments of the factors related to the decision alternatives. In the present study, the authors investigated whether this coherence shift is obtained before people commit to a decision, and whether it is obtained in the course of a number of other processing tasks. College students were presented with a complex legal case involving multiple conflicting arguments. Participants rated agreement with the individual arguments in isolation before seeing the case and after processing it under various initial sets, including playing the role of a judge assigned to decide the case. Coherence shifts were observed when participants were instructed to delay making the decision (Experiment 1), to memorize the case (Experiment 2), and to comprehend the case (Experiment 3). The findings support the hypothesis that a coherence-generating mechanism operates in a variety of processing tasks, including decision making. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Power, efficiency, and thermal characteristics of type-II interbandcascade lasers

High-performance mid-infrared type-II interband cascade lasers have been demonstrated under continuous-wave (CW) conditions with record-high wall-plug efficiencies (>14%) and output powers (>100 mW/facet) above 77 K. Device characteristics of these type-II interband cascade lasers are investigated systematically in terms of their output powers and efficiencies. Also, by comparing the temperature dependence of the threshold currents under pulsed and CW conditions, the thermal resistance and maximum heat sink temperature for CW operation are estimated for several mesa sizes. The limiting factors due to device heating for high-power/high-efficiency operation are identified and discussed in connection with device dimensions and packaging for the purpose of assessing further improvements     

The single-breath nitrogen test in coal miners: factors associated with failure to perform

The objectives of this study were to determine the prevalence of musculoskeletal complaints in a population of lock assemblers in the West Midlands; to follow one group over 12 months and to explore the relationship between survey data, sickness absence information and claims experience. An adapted Nordic Musculoskeletal Questionnaire was used to determine annual and weekly prevalence and annual disability rates for musculoskeletal complaints. There was no statistically significant difference in complaints between the six companies, apart from an increased reporting of neck (p < 0.001), upper back (p < 0.001) and hip (p < 0.05) symptoms at one company (Site 4) during the week prior to the study. When the study was repeated at Site 4 one year later, new employees had significantly fewer complaints of neck and elbow discomfort over the previous year and week, but no difference in wrist complaints was reported. This survey of lock assemblers has highlighted high levels of self-reported upper limb complaints when compared to other referent groups of workers.     

Prediction of solubility of long-chain hydrocarbons in various solvents using UNIFAC

The UNIFAC group contribution model has been widely used in the prediction of phase equilibria of various fluid mixtures. We have applied the method to predict the solubility of various long-chain hydrocarbon solids in a number of solvents of industrial importance. The calculated solubilities are compared with measured values and also with the predictions of the regular solution theory of Hildebrand and Scatchard. Some disagreements were found between the measured solubilities and the predicted values of both theories. Overall the UNIFAC scheme appears to be superior to the regular solution theory.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.