372 research outputs found
Covariation Among Vowel Height Effects on Acoustic Measures
Covariation among vowel height effects on vowel intrinsic fundamental frequency (IF0), voice onset time (VOT), and voiceless interval duration (VID) is analyzed to assess the plausibility of a common physiological mechanism underlying variation in these measures. Phrases spoken by 20 young adults, containing words composed of initial voiceless stops or /s/ and high or low vowels, were produced in habitual and voluntarily increased F0 conditions. High vowels were associated with increased IF0 and longer VIDs. VOT and VID exhibited significant covariation with IF0 only for males at habitua
Hyperinsulinemia improves ischemic LV function in insulin resistant subjects.
BACKGROUND: Glucose is a more efficient substrate for ATP production than free fatty acid (FFA). Insulin resistance (IR) results in higher FFA concentrations and impaired myocardial glucose use, potentially worsening ischemia. We hypothesized that metabolic manipulation with a hyperinsulinemic euglycemic clamp (HEC) would affect a greater improvement in left ventricular (LV) performance during dobutamine stress echo (DSE) in subjects with IR. METHODS: 24 subjects with normal LV function and coronary disease (CAD) awaiting revascularization underwent 2 DSEs. Prior to one DSEs they underwent an HEC, where a primed infusion of insulin (rate 43 mU/m 2/min) was co-administered with 20% dextrose at variable rates to maintain euglycemia. At steady-state the DSE was performed and images of the LV were acquired with tissue Doppler at each stage for offline analysis. Segmental peak systolic velocities (Vs) were recorded, as well as LV ejection fraction (EF). Subjects were then divided into two groups based on their insulin sensitivity during the HEC. RESULTS: HEC changed the metabolic environment, suppressing FFAs and thereby increasing glucose use. This resulted in improved LV performance at peak stress, measured by EF (IS group mean difference 5.3 (95% CI 2.5-8) %, p = 0.002; IR group mean difference 8.7 (95% CI 5.8-11.6) %, p < 0.0001) and peak V s in ischemic segments (IS group mean improvement 0.7(95% CI 0.07-1.58) cm/s, p = 0.07; IR group mean improvement 1.0 (95% CI 0.54-1.5) cm/s, p < 0.0001) , that was greater in the subjects with IR. CONCLUSIONS: Increased myocardial glucose use induced by HEC improves LV function under stress in subjects with CAD and IR. Cardiac metabolic manipulation in subjects with IR is a promising target for future therapy.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Investigating the asymmetry of English sibilant assimilation: Acoustic and EPG data
We present tongue-palate contact (EPG) and acoustic data on English sibilant assimilation, with a particular focus on the asymmetry arising from the order of the sibilants. It is generally known that /s# / sequences may display varying degrees of regressive assimilation in fluent speech, yet for / #s/ it is widely assumed that no assimilation takes place, although the empirical content of this assumption has rarely been investigated nor a clear theoretical explanation proposed. We systematically
compare the two sibilant orders in word-boundary clusters. Our data show that /s# / sequences assimilate frequently and this assimilation is strictly regressive. The assimilated sequence may be indistinguishable from a homorganic control sequence by our measures, or it can be characterized by measurement values intermediate to those typical for / / or /s/. / #s/ sequences may also show regressive assimilation, albeit less frequently and to a lesser degree. Assimilated / #s/ sequences are always distinguishable from /s#s/ sequences. In a few cases, we identify progressive assimilation for / #s/. We discuss how to account for the differences in degree of assimilation, and we propose that the order asymmetry may arise from the different articulatory control structures employed for the two sibilants in conjunction with phonotactic probability effects.casl2pub2269pub
Vowel height and velum position in German: Insights from a real-time magnetic resonance imaging study
Velum position was analysed as a function of vowel height in German tense and lax vowels preceding a nasal or oral consonant. Findings from previous research suggest an interdependence between vowel height and the degree of velum lowering, with a higher velum during high vowels and a more lowered velum during low vowels. In the current study, data were presented from 33 native speakers of Standard German who were measured via non-invasive high quality real-time magnetic resonance imaging. The focus was on exploring the spatiotemporal extent of velum lowering in tense and lax /a, i, o, ø/, which was done by analysing velum movement trajectories over the course of VN and VC sequences in CVNV and CVCV sequences by means of functional principal component analysis. Analyses focused on the impact of the vowel category and vowel tenseness. Data indicated that not only the position of the velum was affected by these factors but also the timing of velum closure. Moreover, it is argued that the effect of vowel height was to be better interpreted in terms of the physiological constriction location of vowels, i.e., the specific tongue position rather than phonetic vowel height
Glucagon-like peptide-1 protects against ischemic left ventricular dysfunction during hyperglycemia in patients with coronary artery disease and type 2 diabetes mellitus.
BACKGROUND: Enhancement of myocardial glucose uptake may reduce fatty acid oxidation and improve tolerance to ischemia. Hyperglycemia, in association with hyperinsulinemia, stimulates this metabolic change but may have deleterious effects on left ventricular (LV) function. The incretin hormone, glucagon-like peptide-1 (GLP-1), also has favorable cardiovascular effects, and has emerged as an alternative method of altering myocardial substrate utilization. In patients with coronary artery disease (CAD), we investigated: (1) the effect of a hyperinsulinemic hyperglycemic clamp (HHC) on myocardial performance during dobutamine stress echocardiography (DSE), and (2) whether an infusion of GLP-1(7-36) at the time of HHC protects against ischemic LV dysfunction during DSE in patients with type 2 diabetes mellitus (T2DM). METHODS: In study 1, twelve patients underwent two DSEs with tissue Doppler imaging (TDI)-one during the steady-state phase of a HHC. In study 2, ten patients with T2DM underwent two DSEs with TDI during the steady-state phase of a HHC. GLP-1(7-36) was infused intravenously at 1.2 pmol/kg/min during one of the scans. In both studies, global LV function was assessed by ejection fraction and mitral annular systolic velocity, and regional wall LV function was assessed using peak systolic velocity, strain and strain rate from 12 paired non-apical segments. RESULTS: In study 1, the HHC (compared with control) increased glucose (13.0 ± 1.9 versus 4.8 ± 0.5 mmol/l, p < 0.0001) and insulin (1,212 ± 514 versus 114 ± 47 pmol/l, p = 0.01) concentrations, and reduced FFA levels (249 ± 175 versus 1,001 ± 333 μmol/l, p < 0.0001), but had no net effect on either global or regional LV function. In study 2, GLP-1 enhanced both global (ejection fraction, 77.5 ± 5.0 versus 71.3 ± 4.3%, p = 0.004) and regional (peak systolic strain -18.1 ± 6.6 versus -15.5 ± 5.4%, p < 0.0001) myocardial performance at peak stress and at 30 min recovery. These effects were predominantly driven by a reduction in contractile dysfunction in regions subject to demand ischemia. CONCLUSIONS: In patients with CAD, hyperinsulinemic hyperglycemia has a neutral effect on LV function during DSE. However, GLP-1 at the time of hyperglycemia improves myocardial tolerance to demand ischemia in patients with T2DM. TRIAL REGISTRATION: http://www.isrctn.org . Unique identifier ISRCTN69686930
A Review of Sarawak Off-Grid Renewable Energy Potential and Challenges
Sarawak is the largest state in Malaysia, in spite of this, the population of Sarawak is relatively small and 42 percent of that population residing in the rural areas. Consequently, the Sarawak government is facing immense challenges in providing basic need such as electricity to the entire state due to the remoteness and small sizes of these settlements. Although the state produces sufficient amount of power, the cost of connecting these rural and non-rural small settlements to the grid is just impractical. The current energy scenario in Sarawak will be reviewed with a focus on the two reliable renewable energy resources currently being pursued by the Local Electrical Authority (LEA) for rural electrification projects which are the Hydro Power and Solar Energy. The paper will address the technical and localized challenges facing the micro-hydro and solar electric energy generation in Sarawak. The micro hydropower potential in Sarawak is estimated at 10.2MW but is not being fully developed due to difficulty in distinctive design and implementation which requires full participation and support from the local community to make it more economically viable and functionality in long run. In addition, Sarawak also receives a daily solar irradiation of more than 5 KWh/m2 throughout the year and that means huge potential for it to thrive. But design and implementation must be done carefully due to the tropical climate and operating temperature of the components. Ultimately, both renewable energy systems require trained personnel to attend to and involvement of LEA or any appointed agency to provide assistance and coordination are necessary to ensure greater success in rural electrification projects
CONDUCTANCE CATHETER DERIVED RIGHT VENTRICULAR DYSFUNCTION IS EVIDENT AFTER BALLOON EXPANDABLE TRANSCUTANEOUS AORTIC VALVE REPLACEMENT IN HUMANS
The influence of photoperiod on the reproductive physiology of the greater red musk shrew (Crocidura flavescens)
Photoperiodism involves the use of both absolute measures of day length and the
direction in which day length is changing as a cue for regulating seasonal changes in
physiology and behaviour so that birth and lactation coincide with optimal resource
availability, increasing offspring survival. Induced ovulation and opportunistic
breeding is often found in species that are predominantly solitary and territorial. In
this study, the photoperiodic reproductive responses of male greater red musk
shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in
the laboratory. The presence of spermatozoa regardless of the light cycle, suggest
that although the shrews are photoresponsive, they may be capable of breeding
throughout the year. Significantly greater testicular volume and seminiferous tubule
diameter following exposure to a short day-light cycle suggests that these animals
may have breeding peaks that correspond to short days. The presence of epidermal
spines on the penis indicates that the shrew is likely also an induced ovulator.
Flexible breeding patterns combined with induced ovulation affords this solitary
species the greatest chance of reproductive success.National Research Foundation (NRF; GUN 64756).http://www.nrcresearchpress.com/journal/cjzhb2016Zoology and Entomolog
Pre-Treatment With Glucagon-Like Peptide-1 Protects Against Ischemic Left Ventricular Dysfunction and Stunning Without a Detected Difference in Myocardial Substrate Utilization
AbstractObjectivesThis study sought to determine whether pre-treatment with intravenous glucagon-like peptide-1 (GLP-1)(7-36) amide could alter myocardial glucose use and protect the heart against ischemic left ventricular (LV) dysfunction during percutaneous coronary intervention.BackgroundGLP-1 has been shown to have favorable cardioprotective effects, but its mechanisms of action remain unclear.MethodsTwenty patients with preserved LV function and single-vessel left anterior descending coronary artery disease undergoing elective percutaneous coronary intervention were studied. A conductance catheter was placed into the LV, and pressure-volume loops were recorded at baseline, during 1-min low-pressure balloon occlusion (BO), and at 30-min recovery. Patients were randomized to receive an infusion of either GLP-1(7-36) amide at 1.2 pmol/kg/min or saline immediately after baseline measurements. Simultaneous coronary artery and coronary sinus blood sampling was performed at baseline and after BO to assess transmyocardial glucose concentration gradients.ResultsBO caused both ischemic LV dysfunction and stunning in the control group but not in the GLP-1 group. Compared with control subjects, the GLP-1 group had a smaller reduction in LV performance during BO (delta dP/dTmax, –4.3 vs. –19.0%, p = 0.02; delta stroke volume, –7.8 vs. –26.4%, p = 0.05), and improved LV performance at 30-min recovery. There was no difference in transmyocardial glucose concentration gradients between the 2 groups.ConclusionsPre-treatment with GLP-1(7-36) amide protects the heart against ischemic LV dysfunction and improves the recovery of function during reperfusion. This occurs without a detected change in myocardial glucose extraction and may indicate a mechanism of action independent of an effect on cardiac substrate use. (Effect of Glucgon-Like-Peptide-1 [GLP-1] on Left Ventricular Function During Percutaneous Coronary Intervention [PCI]; ISRCTN77442023
Distribution Voltage in DC Micro-grid System based Solar PV Topologies Configuration in Sarawak, Malaysia
In the past few decade, longhouse communities in the rural area of Sarawak has been experienced the limitation of electricity supplies. Due to geographic of Sarawak, supply electricity to these rural areas from utility grid through transmission lines also will only results in many losses, the initiation of utilize solar as prime sources is favourable solution. The implementation of DC microgrid system for this area will achieved, as the solar PV system is a DC source to generate electrical supply for appliances in longhouse communities. However, the tropical climate and geographical in Sarawak such as the inconsistent solar radiation, changing temperatures, high humidity and heavy rainfall will be the main restrain to implement solar DC microgrid system. Thus, this paper proposes a comprehensive study about the voltage distribution of DC microgrid configuration in order to investigate system the reliability and efficiency. The configuration of DC micro-grid model has been designed using MATLAB Simulink and an experimental presenting the Simulink also has been developed for validation purposes. The obtained simulation and experimental results confirm that the proposed configuration of the ring system with multiple-sources is more reliable and efficient than radial system with multiple-source configuration in terms of DC voltage distribution at different buses. Thus, the proposed configuration is more reliable according to voltage distribution at each buses
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