Difficult Sequences Research Articles

ChemInform Abstract: Difficult Sequences in Stepwise Peptide Synthesis: Common Molecular Origins in Solution and Solid Phase?

ChemInformVolume 18, Issue 14 Reviews ChemInform Abstract: Difficult Sequences in Stepwise Peptide Synthesis: Common Molecular Origins in Solution and Solid Phase? S. B. H. KENT, S. B. H. KENT Edited by Deber, C. M. ;Hruby, V. J. ;Kopple, K. D. ;Pierce Chem. Co., Rockford, IL, USASearch for more papers by this author S. B. H. KENT, S. B. H. KENT Edited by Deber, C. M. ;Hruby, V. J. ;Kopple, K. D. ;Pierce Chem. Co., Rockford, IL, USASearch for more papers by this author First published: April 7, 1987 https://doi.org/10.1002/chin.198714391Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume18, Issue14April 7, 1987 RelatedInformation

The parameter remapping effect in human performance: Evidence from tongue twisters and finger fumblers

This article describes a series of experiments which show that motor performance suffers when responses in a repeated sequence have variable rather than fixed parameter mappings. In speech production, repeated recitation of the beginning of the alphabet is slowed dramatically if the same letters have different stress levels on successive cycles; the same effect holds for vowel-consonant relationships. In keyboard performance, repetitions of fingertapping sequences suffer if the number of consecutive taps by the same finger changes from cycle to cycle; we call these difficult sequences finger fumblers. Finally, similar effects are obtained with violin playing. The model we develop to account for these results says that parameter values mapped to the subprogram for a response item persist after the subprogram has been executed, and that extra processing is required if a new parameter value must be mapped to the subprogram the next time it is called for. This account is consistent with the view that motor programs for forthcoming actions are prepared by editing motor programs for actions that have just been completed. Because our results are similar to interference effects in traditional memory studies, we also suggest that similar mechanisms underlie storage and retrieval of motor responses and symbolic materials.

Solid phase peptide synthesis using Nα-fluorenylmethoxycarbonylamino acid pentafluorophenyl esters

Fmoc-amino acid pentafluorophenyl esters have been used successfully in the synthesis of a difficult decapeptide sequence using a polar reaction medium and resin support.

The role of the support in solid phase peptide synthesis

The effect of the polymer-support on the kinetics and coupling efficiency of amino acid condensations is described. Changes in the degree of swelling of the support network during peptide synthesis are also evaluated. The advantages of the solid phase method in particularly difficult amino acid sequences are highlighted. Finally, the question of site isolation and its relationship to polystyrene chain flexibility is discussed.

Functional Progressions: An Aid to Athletic Rehabilitation

In brief: Rehabilitation is a critical component of conservative and surgical management of musculoskeletal injuries. Determining whether an athlete has been successfully rehabilitated and may safely return to competition can be difficult. As an adjunct to rehabilitation, functional progressions (a planned, progressively difficult sequence of exercises) can help the clinician determine the status of injured athletes and prepare them for competition. The authors discuss walk-jog, jog-run, and hop-jump sequences among other functional progressions. They recommend that practitioners develop progressions for each athlete to speed rehabilitation and return to activity.

The effects of redundant communications on the behavior of listeners: Does a picture need a thousand words?

Using a referential communication paradigm, two types of, informative messages, contrastive and redundant, were compared developmentally in terms of their relative effects on the accuracy of listeners' responses as a function of task variables. Contrastive messages contained the minimal information necessary to distinguish a referent from a nonreferent. Redundant messages contained additional information. We predicted that redundant messages would be more effective than contrastive ones when the stimulus array was too complex for a listener to notice all aspects of it in the allotted time. Also manipulated were the order of presentation of the message and array and the delay between the two in order to determine how these factors would contribute to task complexity. Subjects were first-and third-graders and college students. The stimuli were drawings of cartoonlike figures. The results confirmed our predictions for the older subjects but not for the younger ones. The discussion of the data centered on why the picture-message sequence, was a more difficult sequence than the message-picture one for all age groups.

Acoustic cues in the identification of vowel sequences

We have observed that at 30‐ and 60‐ms durations some permuted orders of 4 synthetic vowels /i, æ, a, u/ were much more identifiable than others using a single sequence method [Kerivan, Alfonso, and Bornstein, J. Acoust. Soc. Am. Suppl. 1 65, S113(A) (1979)]. Also, significant improvements in identification of difficult sequences occurred when silent gaps were placed between selected vowels resulting in a rhythmic grouping of the sequence. These findings have been correlated to the various acoustic parameters used to synthesize the vowels. The results of these multiple correlations show that the identification of vowels in sequence follows the laws of pitch continuity established by numerous investigators using tonal sequences. The more monotonic pitch continuity displayed by adjacent first formants the better is sequence identification. A similar but weaker correlation was found between sequence identification and pitch proximity of fundamental frequencies. An interaction was also found between pitch and loudness of adjacent fundamental and formant frequencies. The relative intensity differences for all first formants were within 3 dB; however, those for fundamental frequencies were as disparate as 11 dB. It appears that the ear primarily tracks the first formant of each vowel complex in determining vowel identity in the sequence. [Work supported by an NINCDS NIH grant awarded to Haskins Laboratories and the University of Connecticut Research Foundation.]

THE PREDICTION AND ACQUISITION OF SEQUENTIAL PATTERNS OF BINARY EVENTS

Patterns of events 2, 4, 6, 8 and 10 event runs in length with average run lengths of 2, 3, 4 and 6 events were learned by 16 practised subjects. Increased difficulty was most clearly related to an increase in runs per sequence rather than the sequence length per se, although the generality of the effect is limited. Initial prediction strategies were maintained throughout the acquisition of simple sequences. The more difficult sequences, however, went through several stages of increased prediction accuracy. The elimination of errors on specific events in sequences showed evidence for strategic behaviour (i.e. consistent prediction) only on the relatively short or the relatively difficult sequences. For individual subjects efficient acquisition correlated with consistent response strategies and with a measure of ‘insight’ in acquisition. Response strategy and ‘insight’ did not correlate significantly with each other, however.