A validated and stability indicating HPLC method for analysis of diminazene aceturate and antipyrine combination in a ready injectable solution

Diminazene aceturate and Antipyrine combination therapy is widely used in veterinary medicine. A simple reverse HPLC method for the analysis of samples of a ready injectable formulation containing a mixture of active ingredients and inactive excipients has been developed. The HPLC analysis was carried out using a reversed phase (RP)-C18 (250 mm×4.0 mm, 5 μm) column. The isocratic mobile phase consisted of a mixture of acetonitrile, methanol, phosphate buffer and hexane sulfonate; the flow rate was 0.6 mL/min and ultraviolet detection was at 291 nm. This method was validated in accordance with FDA and ICH guidelines and showed good linearity, accuracy, precision, selectivity and the system suitability results were within the acceptance criteria. A stability-indicating study was also carried out and indicated that this method could be used for purity and degradation evaluation of these formulations.

Alice's adventures in um-derland: Psycholinguistic sources of variation in disfluency production

This study tests the hypothesis that three common types of disfluency (fillers, silent pauses, and repeated words) reflect variance in what strategies are available to the production system for responding to difficulty in language production. Participants' speech in a storytelling paradigm was coded for the three disfluency types. Repeats occurred most often when difficult material was already being produced and could be repeated, but fillers and silent pauses occurred most when difficult material was still being planned. Fillers were associated only with conceptual difficulties, consistent with the proposal that they reflect a communicative signal whereas silent pauses and repeats were also related to lexical and phonological difficulties. These differences are discussed in terms of different strategies available to the language production system.

Interpreting Pitch Accents in Online Comprehension: H* vs. L+H*

Although the presence or absence of a pitch accent clearly can play an important role in signaling the discourse and information structure of an utterance, whether the form of an accent determines the type of information it conveys is more controversial. We used an eye-tracking paradigm to investigate whether H*, which has been argued to signal new information, evokes different eye fixations than L+H*, which has been argued to signal the presence of contrast. Our results demonstrate that although listeners interpret these accents differently, their interpretive domains overlap. L+H* creates a strong bias toward contrast referents whereas H* is compatible with both new and contrast referents.

The effects of age on the strategic use of pitch accents in memory for discourse: a processing-resource account

In two experiments, we investigated age-related changes in how prosodic pitch accents affect memory. Participants listened to recorded discourses that contained two contrasts between pairs of items (e.g., one story contrasted British scientists with French scientists and Malaysia with Indonesia). The end of each discourse referred to one item from each pair; these references received a pitch accent that either denoted contrast (L + H* in the ToBI system) or did not (H*). A contrastive accent on a particular pair improved later recognition memory equally for young and older adults. However, older adults showed decreased memory if the other pair received a contrastive accent (Experiment 1). Young adults with low working memory performance also showed this penalty (Experiment 2). These results suggest that pitch accents guide processing resources to important information for both older and younger adults but diminish memory for less important information in groups with reduced resources, including older adults.

Transcriptional regulation of neurodevelopmental and metabolic pathways by NPAS3

The basic helix-loop-helix PAS (Per, Arnt, Sim) domain transcription factor gene NPAS3 is a replicated genetic risk factor for psychiatric disorders. A knockout (KO) mouse model exhibits behavioral and adult neurogenesis deficits consistent with human illness. To define the location and mechanism of NPAS3 etiopathology, we combined immunofluorescent, transcriptomic and metabonomic approaches. Intense Npas3 immunoreactivity was observed in the hippocampal subgranular zone-the site of adult neurogenesis--but was restricted to maturing, rather than proliferating, neuronal precursor cells. Microarray analysis of a HEK293 cell line over-expressing NPAS3 showed that transcriptional targets varied according to circadian rhythm context and C-terminal deletion. The most highly up-regulated NPAS3 target gene, VGF, encodes secretory peptides with established roles in neurogenesis, depression and schizophrenia. VGF was just one of many NPAS3 target genes also regulated by the SOX family of transcription factors, suggesting an overlap in neurodevelopmental function. The parallel repression of multiple glycolysis genes by NPAS3 reveals a second role in the regulation of glucose metabolism. Comparison of wild-type and Npas3 KO metabolite composition using high-resolution mass spectrometry confirmed these transcriptional findings. KO brain tissue contained significantly altered levels of NAD(+), glycolysis metabolites (such as dihydroxyacetone phosphate and fructose-1,6-bisphosphate), pentose phosphate pathway components and Kreb's cycle intermediates (succinate and α-ketoglutarate). The dual neurodevelopmental and metabolic aspects of NPAS3 activity described here increase our understanding of mental illness etiology, and may provide a mechanism for innate and medication-induced susceptibility to diabetes commonly reported in psychiatric patients.

The disfluent discourse: Effects of filled pauses on recall

We investigated the mechanisms by which fillers, such as uh and um, affect memory for discourse. Participants listened to and attempted to recall recorded passages adapted from Alice's Adventures in Wonderland. The type and location of interruptions were manipulated through digital splicing. In Experiment 1, we tested a processing time account of fillers' effects. While fillers facilitated recall, coughs matched in duration to the fillers impaired recall, suggesting that fillers' benefits cannot be attributed to adding processing time. In Experiment 2, fillers' locations were manipulated based on norming data to be either predictive or non-predictive of upcoming material. Fillers facilitated recall in both cases, inconsistent with an account in which listeners predict upcoming material using past experience with the distribution of fillers. Instead, these results suggest an attentional orienting account in which fillers direct attention to the speech stream but do not always result in specific predictions about upcoming material.

Effects of pitch accents in attachment ambiguity resolution

Previous work has found that listeners prefer to attach ambiguous syntactic constituents to nouns produced with a pitch accent (Schafer et al., 1996). This study examines what factors underlie previously established accent attachment effects by testing whether these effects are driven by a preference to attach syntactic constituents to new or important information (the Syntax Hypothesis) or whether there is a bias to respond to post-sentence probe questions with an accented word (the Salience Hypothesis). One of the predictions of the Salience Hypothesis is that selection of accented words should be greater when a sentence is complex and processing resources are limited. The results from the experiments presented here show that the probability of listeners' selecting accented words when asked about the interpretation of a relative clause varies with sentence type: listeners selected accented words more frequently in long sentences than in short sentences, consistent with the predictions of the Salience Hypothesis. Furthermore, Experiment 4 demonstrates that listeners are more likely to respond to post-sentence questions with accented words than with non-accented words, even when no ambiguity is present, and even when the response results in an incorrect answer. These findings suggest that accent-driven attachment effects found in earlier studies reflect a post-sentence selection process rather than a syntactic processing mechanism.

Recognition memory reveals just how CONTRASTIVE contrastive accenting really is

The effects of pitch accenting on memory were investigated in three experiments. Participants listened to short recorded discourses that contained contrast sets with two items (e.g. British scientists and French scientists); a continuation specified one item from the set. Pitch accenting on the critical word in the continuation was manipulated between non-contrastive (H* in the ToBI system) and contrastive (L+H*). On subsequent recognition memory tests, the L+H* accent increased hits to correct statements and correct rejections of the contrast item (Experiments 1-3), but did not impair memory for other parts of the discourse (Experiment 2). L+H* also did not facilitate correct rejections of lures not in the contrast set (Experiment 3), indicating that contrastive accents do not simply strengthen the representation of the target item. These results suggest comprehenders use pitch accenting to encode and update information about multiple elements in a contrast set.

Recognition memory reveals just how CONTRASTIVE contrastive accenting really is

The effects of pitch accenting on memory were investigated in three experiments. Participants listened to short recorded discourses that contained contrast sets with two items (e.g. British scientists and French scientists); a continuation specified one item from the set. Pitch accenting on the critical word in the continuation was manipulated between non-contrastive (H* in the ToBI system) and contrastive (L+H*). On subsequent recognition memory tests, the L+H* accent increased hits to correct statements and correct rejections of the contrast item (Experiments 1-3), but did not impair memory for other parts of the discourse (Experiment 2). L+H* also did not facilitate correct rejections of lures not in the contrast set (Experiment 3), indicating that contrastive accents do not simply strengthen the representation of the target item. These results suggest comprehenders use pitch accenting to encode and update information about multiple elements in a contrast set.

Use of a solvent-free dry matrix coating for quantitative matrix-assisted laser desorption ionization imaging of 4-bromophenyl-1,4-diazabicyclo(3.2.2)nonane-4-carboxylate in rat brain and quantitative analysis of the drug from laser microdissected tissue regions

A dry matrix application for matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) was used to profile the distribution of 4-bromophenyl-1,4-diazabicyclo(3.2.2)nonane-4-carboxylate, monohydrochloride (BDNC, SSR180711) in rat brain tissue sections. Matrix application involved applying layers of finely ground dry alpha-cyano-4-hydroxycinnamic acid (CHCA) to the surface of tissue sections thaw mounted onto MALDI targets. It was not possible to detect the drug when applying matrix in a standard aqueous-organic solvent solution. The drug was detected at higher concentrations in specific regions of the brain, particularly the white matter of the cerebellum. Pseudomultiple reaction monitoring imaging was used to validate that the observed distribution was the target compound. The semiquantitative data obtained from signal intensities in the imaging was confirmed by laser microdissection of specific regions of the brain directed by the imaging, followed by hydrophilic interaction chromatography in combination with a quantitative high-resolution mass spectrometry method. This study illustrates that a dry matrix coating is a valuable and complementary matrix application method for analysis of small polar drugs and metabolites that can be used for semiquantitative analysis.

A solvent-free matrix application method for matrix-assisted laser desorption/ionization imaging of small molecules

Matrix application continues to be a critical step in sample preparation for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI). Imaging of small molecules such as drugs and metabolites is particularly problematic because the commonly used washing steps to remove salts are usually omitted as they may also remove the analyte, and analyte spreading is more likely with conventional wet matrix application methods. We have developed a method which uses the application of matrix as a dry, finely divided powder, here referred to as dry matrix application, for the imaging of drug compounds. This appears to offer a complementary method to wet matrix application for the MALDI-MSI of small molecules, with the alternative matrix application techniques producing different ion profiles, and allows the visualization of compounds not observed using wet matrix application methods. We demonstrate its value in imaging clozapine from rat kidney and 4-bromophenyl-1,4-diazabicyclo(3.2.2)nonane-4-carboxylic acid from rat brain. In addition, exposure of the dry matrix coated sample to a saturated moist atmosphere appears to enhance the visualization of a different set of molecules.

Accent detection is a slippery slope: Direction and rate of F0 change drives listeners' comprehension

The present study tests whether listeners use F0, duration, or some combination of the two to identify the presence of an accented word in a short discourse. Participants' eye movements to previously mentioned and new objects were monitored as participants listened to instructions to move objects in a display. The name of the target object on critical trials was resynthesized from naturally-produced utterances so that it had either high or low F0 and either long or short duration. Fixations to the new object were highest when there was a steep rise in F0. Fixations to the previously mentioned object were highest when there was a steep drop in F0. These results suggest that listeners use F0 slope to make decisions about the presence of an accent, and that F0 and duration by themselves do not solely determine accent interpretation.

Experimental and theoretical advances in prosody: A review

Research on prosody has recently become an important focus in various disciplines, including Linguistics, Psychology, and Computer Science. This article reviews recent research advances on two key issues: prosodic phrasing and prosodic prominence. Both aspects of prosody are influenced by linguistic factors such as syntactic constituent structure, semantic relations, phonological rhythm, pragmatic considerations, and also by processing factors such as the length, complexity or predictability of linguistic material. Our review summarizes recent insights into the production and perception of these two components of prosody and their grammatical underpinnings. While this review only covers a subset of a broader set of research topics on prosody in cognitive science, they are representative of a tendency in the field toward a more interdisciplinary approach.

Penetration of topical and subconjunctival corticosteroids into human aqueous humour and its therapeutic significance

Topical and subconjunctival corticosteroids are some of the most effective and compelling treatment options in ocular inflammatory diseases. A systematic review of literature indexed by Ovid MEDLINE & EMBASE was performed up to December 2008. There are few studies on their aqueous penetration in human subjects. This review article discusses the penetration of different ocular corticosteroids into human aqueous humour along with the therapeutic implications on management of ocular surface diseases, immune-related corneal diseases, anterior uveitis and postoperative anti-inflammatory use. In the context of the paucity of well-constructed, prospective clinical trials comparing the efficacy of different corticosteroids, it provides guiding principles for the use of topical corticosteroids. Dexamethasone alcohol 0.1% and prednisolone acetate 1% are potent corticosteroids, but the latter achieves the highest aqueous concentration within 2 h and maintains higher levels for 24 h. Subconjunctival corticosteroids provide very high concentrations in the aqueous which maintain higher concentrations for longer periods.

A chemometric study of chromatograms of tea extracts by correlation optimization warping in conjunction with PCA, support vector machines and random forest data modeling

A reverse phase high performance liquid chromatography (HPLC) separation was established for profiling water soluble compounds in extracts from tea. Whole chromatograms were pre-processed by techniques including baseline correction, binning and normalisation. In addition, peak alignment by correction of retention time shifts was performed using correlation optimization warping (COW) producing a correlation score of 0.96. To extract the chemically relevant information from the data, a variety of chemometric approaches were employed. Principle component analysis (PCA) was used to group the tea samples according to their chromatographic differences. Three principal components (PCs) described 78% of the total variance after peak alignment (64% before) and analysis of the score and loading plots provided insight into the main chemical differences between the samples. Finally, PCA, support vector machines (SVMs) and random forest (RF) machine learning methods were evaluated comparatively on their ability to predict unknown tea samples using models constructed from a predetermined training set. The best predictions of identity were obtained by using RF.

Metabolomic profiling of Drosophila using liquid chromatography Fourier transform mass spectrometry

Hydrophilic interaction chromatography (HILIC) interfaced with an Orbitrap Fourier transform mass spectrometer (FT-MS) was used to carry out metabolomic profiling of the classical Drosophila mutation, rosy (ry). This gene encodes a xanthine oxidase/dehydrogenase. In addition to validating the technology by detecting the same changes in xanthine, hypoxanthine, urate and allantoin that have been reported classically, completely unsuspected changes were detected in each of the tryptophan, arginine, pyrimidine and glycerophospholipid metabolism pathways. The rosy mutation thus ramifies far more widely than previously detected.

Metabolomic profiling using Orbitrap Fourier transform mass spectrometry with hydrophilic interaction chromatography: a method with wide applicability to analysis of biomolecules

It was shown that coupling hydrophilic interaction chromatography (HILIC) to Orbitrap Fourier transform mass spectrometery (FT-MS) provided an excellent tool for metabolic profiling, principally due to rapid elution of lipids in advance of most metabolites entering the mass spectrometer. We used in vitro cultivated procyclic forms of the protozoan parasite Trypanosoma brucei as a source of metabolites to test the performance of the HILIC column and the mass accuracy of MS. The mass accuracy achieved fell within 2 ppm for all the metabolites identified within samples. It was, for example, possible to identify the signature metabolite of the trypanosome, trypanothione, and also glutathione which were well retained by the HILIC column. By comparing trypanosomes grown in two different media we were able to clearly distinguish the samples in terms of the relative abundance of a number of metabolites using Sieve 1.1 software.