This paper evaluates the aggregation behavior of a potential drug and gene delivery system that combines branched polyethyleneimine (PEI), a positively-charged polyelectrolyte, and elastin-like polypeptide (ELP), a recombinant polymer that exhibits lower critical solution temperature (LCST). The LCST behavior of ELP has been extensively studied, but there are no quantitative ways to control the size of aggregates formed after the phase transition. The aggregate size cannot be maintained when the temperature is lowered below the LCST, unless the system exhibits hysteresis and forms irreversible aggregates. This study shows that conjugation of ELP with PEI preserves the aggregation behavior that occurs above the LCST and achieves precise aggregate radii when the solution conditions of pH (3, 7, 10), polymer concentration (0.1, 0.15, 0.3 mg/mL), and salt concentration (none, 0.2, 1 M) are carefully controlled. K-means cluster analyses showed that salt concentration was the most critical factor controlling the hydrodynamic radius and LCST. Conjugating ELP to PEI allowed crosslinking the aggregates and achieved stable particles that maintained their size below LCST, even after removal of the harsh (high salt or pH) conditions used to create them. Taken together, the ability to control aggregate sizes and use of crosslinking to maintain stability holds excellent potential for use in biological delivery systems.
It is widely accepted that internal constraints on variation are not modulated by social and stylistic factors (e.g., Labov, 2010:265). Is this also true for register differences as a special type of sociostylistic factor? To address this question, we investigate future temporal reference (FTR) variation in English (It'll be fun versus It's gonna be fun) via a variationist corpus study (n = 2,600 tokens) and a supplementary rating experiment (n = 114 participants) across four broad registers: conversations, parliamentary debates, blogs, and newspaper prose. Multivariate analysis of the corpus dataset indicates that register modulates the effect of five out of nine internal constraints, suggesting that variable grammars vary considerably across registers. The experiment confirms that language users are indeed sensitive to, and aware of, the register-specificity of how variation is conditioned. We conclude by discussing the implications of our findings for variationist sociolinguistics and for variational linguistics in general.
In this paper, we operationalize register differences at the intersection of formality and mode, and distinguish four broad register categories: spoken informal (conversations), spoken formal (parliamentary debates), written informal (blogs), and written formal (newspaper articles). We are specifically interested in the comparative probabilistic/variationist complexity of these registers – when speakers have grammatical choices, are the probabilistic grammars regulating these choices more or less complex in particular registers than in others? Based on multivariate modeling of richly annotated datasets covering three grammatical alternations in two languages (English and Dutch), we assess the complexity of probabilistic grammars by drawing on three criteria: (a) the number of constraints on variant choice, (b) the number of interactions between constraints, and (c) the relative importance of lexical conditioning. Analysis shows that contrary to theorizing in variationist sociolinguistics, probabilistic complexity differences between registers are not quantitatively simple: formal registers are consistently the most complex ones, while spoken registers are the least complex ones. The most complex register under study is written-formal quality newspaper writing. We submit that the complexity differentials we uncover are a function of acquisitional difficulty, of on-line processing limitations, and of normative pressures.
Previous research has shown that talker identity and speaking style affect the processing of morphosyntactic violations. The present study examined whether speaking style modulates comprehension and subsequent production of case variants in German prepositional phrases across the lifespan. To this end, we conducted a sentence repetition and completion experiment with young and older adults. After a familiarization phase with two talkers (one with a careful pronunciation and one with a casual pronunciation), participants were asked to repeat utterances produced by these two talkers. Critical case markers were replaced by white noise. The results showed a main effect of speaking style in the responses of both age groups, suggesting that young and older adults can adjust their expectations about variants usage to the talker's speaking style and can alter their subsequent production accordingly. These findings have implications for research on processing and producing morphosyntactic variation and expectation-based language processing.
Recent evidence suggests that probabilistic grammars may be modulated by communication mode and genre. Accordingly, the question arises how complex language users’ lectal competence is, where complexity is proportional to the extent to which choice-making processes depend on the situation of language use. Do probabilistic constraints vary when we talk to a friend compared to when we give a speech? Are differences between spoken and written language larger than those within each mode? In the present study, we aim to approach these questions systematically. Guided by theorizing in cognitive (socio)linguistics and using logistic regression based on corpus materials, we analyzed the dative alternation with give (The government gives farmers money vs. The government gives money to farmers) in four broad registers of English: spoken informal, spoken formal, written informal, and written formal. Corpus analysis was supplemented with a scalar rating experiment. Results suggest that language users’ probabilistic grammars vary as a function of register.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.