High‐Performance Materials for 3D Printing in Chemical Synthesis Applications

3D printing has emerged as an enabling technology for miniaturization. High‐precision printing techniques such as stereolithography are capable of printing microreactors and lab‐on‐a‐chip devices for efficient parallelization of biological and biochemical reactions under reduced uptake of reactants. In the world of chemistry, however, up until now, miniaturization has played a minor role. The chemical and thermal stability of regular 3D printing resins is insufficient for sustaining the harsh conditions of chemical reactions. Novel material formulations that produce highly stable 3D‐printed chips are highly sought for bringing chemistry up‐to‐date on the development of miniaturization. In this work, a brief review of recent developments in highly stable materials for 3D printing is given. This work focuses on three highly stable 3D‐printable material systems: transparent silicate glasses, ceramics, and fluorinated polymers. It is further demonstrated that 3D printing is also a versatile technique for surface structuring of polymers to enhance their wetting performance. Such micro/nanostructuring is key to selectively wetting surface patterns that are versatile for chemical arrays and droplet synthesis.     

Efficient Parallel Matrix Inversion on Interconnection Networks

In this paper, we present efficient algorithms for the inversion of a triangular matrix on different interconnection networks. For hypercubes, we describe an elegant straightforward implementation of L. Csansky's well known PRAM algorithm [Ph.D. dissertation, Computer Sci. Div., Univ. of California, Berkeley 1974]. The time complexity is (log²n) usingn³processors, i.e., within the same order as the PRAM algorithm. Moreover, we give a general approach for the design of triangular matrix inversion algorithms on a large class of networks. Applied to some of these networks, as, e.g., the de Bruijn network, the shuffle-exchange network, and the cube-connected-cycles, this approach yields triangular matrix inversion algorithms that meet the PRAM complexity bounds of the problem within a small constant.     

Simultaneous phenol removal and biological reduction of hexavalent chromium in a packed‐bed reactor

BACKGROUND: Phenol and hexavalent chromium are considered industrial pollutants that pose severe threats to human health and the environment. The two pollutants can be found together in aquatic environments originating from mixed discharges of many industrial processes, or from a single industry discharge. The main objective of this work was to study the feasibility of using phenol as an electron donor for Cr(VI) reduction, thus achieving the simultaneous biological removal/reduction of the two pollutants in a packed‐bed reactor. RESULTS: A pilot‐scale packed‐bed reactor was used to estimate phenol removal with simultaneous Cr(VI) reduction through biological mechanisms, using a new mixed bacterial culture originated from Cr(VI)‐reducing and phenol‐degrading bacteria, operated in draw–fill mode with recirculation. Experiments were performed for feed Cr(VI) concentration of about 5.5 mg L^?1, while phenol concentration ranged from 350 to 1500 mg L^?1. The maximum reduction/removal rates achieved were 0.062 g Cr(VI) L^?1 d^?1 and 3.574 g phenol L^?1 d^?1, for a phenol concentration of 500 mg L^?1. CONCLUSION: Phenol removal with simultaneous biological Cr(VI) reduction is feasible in a packed‐bed attached growth bioreactor. Phenol was found to inhibit Cr(VI) reduction, while phenol removal was rather unaffected by Cr(VI) concentration increase. However, the recorded removal rates of phenol and Cr(VI) were found to be much lower than those obtained from previous research, where the two pollutants were examined separately. Copyright © 2008 Society of Chemical Industry     

Global folding of proteins using a limited number of distance constraints

A Monte Carlo method is presented which can obtain the correcttertiary fold of a protein given the secondary structure andas few as three interactions between each secondary structureunit. This method was used to fold hemerythrin, Qavodoxin, bovinepancreatic trypsin inhibitor and a variable light domain froman immunoglobulin using the known secondary structures of theseproteins. Each of the proteins was successfully folded to obtaina structure resembling the initial X-ray structure. Reasonablesuccess was also achieved when using a secondary structure predictionalgorithm to assign secondary structure. The r.m.s. deviationsbetween the folded proteins and the crystal structures are inthe order of 3–5 A for the backbone coordinates. Evaluationof the r.m.s. deviations between members of the globin familyindicates that two equivalent overall folds may have r.m.s.deviations of this or even larger magnitude. The limiting numberof constraints necesssary to achieve the correct fold is discussed.     

Schizophrenic patients in the psychiatric interview: An experimental study of their effectiveness at manipulation.

This study attempted to examine whether chronic schizophrenic patients could effectively engage in the manipulative strategy of impression management in an evaluative interview situation. The data supported the expectation that schizophrenic mental patients can effectively present themselves as "sick" or "healthy," whichever is more suited to their needs and goals. Thus, when the patients' open ward status was questioned, they convincingly presented themselves in the interview as "healthy" and eligible for open ward living; when their residency status was questioned, they convincingly presented themselves as "sick" and ineligible for discharge. These findings were interpreted as supporting assumptions of patient effectiveness in implementing goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methodische Untersuchungen zur phasentrennenden Fraktionierung von Polycaprolactam,

The carbonyl group concentration was determined with C-14 labelled 2,4-dinitrophenylhydrazine in the following substances: pergamin, filterpaper, cellophane, polyethylene and polypropylen. For standardizing the method, the MALAPRADE-splitting of the C₂? C₃-bond in the glucosidic unit of celluloses was used. The reactivity towards NaJO₄ increased in the following way: cellophane < filterpaper < pergamin.     

Development and evaluation of microarray-based whole-genome hybridization for detection of microorganisms within the context of environmental applications

The detection and identification of microorganisms in natural communities is a great challenge to biologists. Microarray-based genomic technology provides a promising high-throughput alternative to traditional microbial characterization. A novel prototype microarray containing whole genomic DNA, termed community genome array (CGA), was constructed and evaluated. Microarray hybridizations at 55 degrees C using 50% formamide permitted the examined bacteria to be distinguished at the species level, while strain-level differentiation was obtained at hybridization temperatures of 65 or 75 degrees C. The detection limit was estimated to be approximately 0.2 ng with genomic DNA from a single pure culture using a reduced hybridization volume (3 microL). Using mixtures of known amounts of DNA or a known number of cells from 14 or 16 different species, respectively, about 5 ng of genomic DNA or 2.5 x 10(5) cells were detected under the hybridization conditions used. In addition, strong linear relationships were observed between hybridization signal intensity and target DNA concentrations for pure cultures, a mixture of DNA templates, and a population of mixed cells (r2 = 0.95-0.98, P < 0.01). Finally, the prototype CGA revealed differences in microbial community composition in soil, river, and marine sediments. The results suggest that CGA hybridization has potential as a specific, sensitive, and quantitative tool for detection and identification of microorganisms in environmental samples.