1,367 research outputs found
Status report the SRC-1 and SRC-2 processes
Bench-scale and pilot plant development of solvent refined coal (SRC) processes is reviewed. Large SRC demonstration plants are described. Commercialization of the process is envisioned for the 1980's
Next generation hairpin polyamides with (R)-3,4-diaminobutyric acid turn unit
The characterization of a new class of pyrrole−imidazole hairpin polyamides with β-amino-γ-turn units for recognition of the DNA minor groove is reported. A library of eight hairpins containing (R)- and (S)-3,4-diaminobutyric acid (β-amino-γ-turn) has been synthesized, and the impact of the molecules on DNA-duplex stabilization was studied for comparison with the parent γ-aminobutyric acid (γ-turn) and standard (R)-2,4-diaminobutyric acid (α-amino-γ-turn)-linked eight-ring polyamides. For some, but not all, sequence compositions, melting temperature analyses have revealed that both enantiomeric forms of the β-amino-γ-turn increase the DNA-binding affinity of polyamides relative to the (R)-α-amino-γ-turn. The (R)-β-amine residue may be an attractive alternative for constructing hairpin polyamide conjugates. Biological assays have shown that (R)-β-amino-γ-turn hairpins are able to inhibit androgen receptor-mediated gene expression in cell culture similar to hairpins bearing the standard (R)-α-amino-γ-turn, from which we infer they are cell-permeable
Attitudes and Preferences of ESL Students to Error Correction
This article presents the findings of a survey of ESL students' attitudes toward and preferences for the correction of spoken errors by native speaker friends. The 418 subjects reported generally positive attitudes toward error correction, and claimed to prefer even more correction than their friends did. They saw correcting errors as facilitating--even being necessary--for the improvement of their oral English
Error Correction in Native-Nonnative Conversation
The purpose of this paper is to report the results of an investigation into how native speakers (NSs) of English in social settings correct the errors committed by their friends who are nonnative speakers (NNSs) of English. While there are a number of studies which describe error correction in the second/foreign language classroom (e.g., Allwright 1975; Fanselow 1977; Holley and King 1971), little is known about what NSs do when their NNS friends commit errors. Gaskill (1980) studied sample conversations of one NNS with several NSs. He concluded that when, and if, NS correction occurs, it is usually modulated in form to show NS uncertainty. However, as Cathcart and Olsen (1976) noted, personalities involved in the interaction affect the amount and type of correction supplied. Since Gaskill had only one NNS as his source of data, his results may not be representative.
The NSs in our data used two strategies tocorrect NNS errors: on-record corrections off-record corrections. After describing the subjects and the methods used in collecting the data, we discuss in detail these two strategies. We also present, by way of contrast, several noncorrective discourse strategies which NSs used in order to clear up conversational difficulties. A model of error correction is proposed, which shows that most NS error corrections were given at transition points and not as interruptions. The paper concludes with implications of the results for the classroom and with suggestions for future research
Microwave Assisted Synthesis of Py-Im Polyamides
Microwave synthesis was utilized to rapidly build Py-Im polyamides in high yields and purity using Boc-protection chemistry on Kaiser oxime resin. A representative polyamide targeting the 5′-WGWWCW-3′ (W = A or T) subset of the consensus Androgen and Glucocorticoid Response Elements was synthesized in 56% yield after 20 linear steps and HPLC purification. It was confirmed by Mosher amide derivatization of the polyamide that a chiral α-amino acid does not racemize after several additional coupling steps
Expanding the Repertoire of Natural Product-Inspired Ring Pairs for Molecular Recognition of DNA
A furan amino acid, inspired by the recently discovered proximicin natural products, was incorporated into the scaffold of a DNA-binding hairpin polyamide. While unpaired oligomers of 2,4-disubstituted furan amino acids show poor DNA-binding activity, furan (Fn) carboxamides paired with N-methylpyrrole (Py) and N-methylimidazole (Im) rings demonstrate excellent stabilization of duplex DNA as well as discrimination of noncognate sequences, consistent with function as a Py mimic according to the Py/Im polyamide pairing rules
Melting of Partially Fluorinated Graphene: From Detachment of Fluorine Atoms to Large Defects and Random Coils
The melting of fluorographene is very unusual and depends strongly on the
degree of fluorination. For temperatures below 1000 K, fully fluorinated
graphene (FFG) is thermo-mechanically more stable than graphene but at
T2800 K FFG transits to random coils which is almost twice lower
than the melting temperature of graphene, i.e. 5300 K. For fluorinated graphene
(PFG) up to 30 % ripples causes detachment of individual F-atoms around 2000 K
while for 40-60 % fluorination, large defects are formed beyond 1500 K and
beyond 60% of fluorination F-atoms remain bonded to graphene until melting. The
results agree with recent experiments on the dependence of the reversibility of
the fluorination process on the percentage of fluorination.Comment: 16 pages, 6 figure
Prevention of Catheter-Related Blood Stream Infection: Back to Basics?
Background: Central venous catheter (CVC)-related infections are a substantial problem in the intensive care unit (ICU). Our infection control team initiated the routine use of antiseptic-coated (chlorhexidine-silver sulfadiazine; Chx-SS) CVCs in our adult ICUs to reduce catheter-associated (CA) and catheter-related (CR) blood stream infection (BSI) as we implemented other educational and best practice standardization strategies. Prior randomized studies documented that the use of Chx-SS catheters reduces microbial colonization of the catheter compared with an uncoated standard (Std) CVC but does not reduce CR-BSI. We therefore implemented the routine use of uncoated Std CVCs in our surgical ICU (SICU) and examined the impact of this change. Hypothesis: The use of uncoated Std CVCs does not increase CR-BSI rate in an SICU. Methods: Prospective evaluation of universal use of uncoated Std CVCs, implemented November 2007 in the SICU. The incidences of CA-BSI and CR-BSI were compared during November 2006-October 2007 (universal use of Chx-SS CVCs) and November 2007-October 2008 (universal use of Std CVCs) by t-test. The definitions of the U.S. Centers for Disease Control and Prevention were used for CA-BSI and CR-BSI. Patient data were collected via a dedicated Acute Physiology and Chronic Health Evaluation (APACHE) III coordinator for the SICU. Results: Annual use of CVCs increased significantly in the last six years, from 3,543 (2001) to 5,799 (2006) total days. The APACHE III scores on day 1 increased from a mean of 54.4 in 2004 to 55.6 in 2008 (p = 0.0010; 95% confidence interval [CI] 1.29-5.13). The mean age of the patients was unchanged over this period, ranging from 58.2 to 59.6 years. The Chx-SS catheters were implemented in the SICU in 2002. Data regarding the specific incidence of CR-BSI were collected beginning at the end of 2005, with mandatory catheter tip cultures when CVCs were removed. Little difference was identified in the incidence of BSI between the interval with universal Chx-SS use and that with Std CVC use. (Total BSI 0.7 vs. 0.8 per 1,000 catheter days; CA-BSI 0.5 vs. 0.8 per 1,000 catheter days; CR-BSI 0.2 vs. 0 per 1,000 catheter days.) No difference was seen in the causative pathogens of CA-BSI or CR-BSI. Conclusion: Eliminating the universal use of Chx-SS-coated CVCs in an SICU with a low background incidence of CR-BSIs did not result in an increase in the rate of CR-BSIs. This study documents the greater importance of adherence to standardization of the processes of care related to CVC placement than of coated CVC use in the reduction of CR-BSI.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90456/1/sur-2E2009-2E082.pd
Economic Backwardness and Social Tension
We propose that relative economic backwardness contributes to the build-up of social tension and non-violent and violent conflict. We test our hypothesis using data on organized mass movements and armed civil conflict. The findings show that greater economic backwardness is consistently linked to a higher probability of onset of violent and especially non-violent forms of civil unrest. We provide evidence that the relationship is causal in instrumental variables estimations using new instruments, including mailing speeds and telegram charges around 1900. The magnitude of the effect of backwardness on social tension increases in the two-stage least-squares estimations
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