2,455 research outputs found

    Esterification of Acetic Acid with Butanol: Operation in a Packed Bed Reactive Distillation Column

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    The esterification reaction between acetic acid and butanol was investigated in a reactive distillation column. The thermodynamic aspects of considered system are discussed, equilibrium constant, vapor pressures and UNIQUAC interaction parameters were investigated. Reactive distillation experiments were carried out to provide high purity butyl acetate. For this purpose, a 2 m column with nonreactive and reactive zones filled with Amberlyst 15 and Raschig rings, were used in the experiments. Several operating conditions such as total feed flow rate, molar ratio of butanol to acetic acid, amount of catalyst and reboiler temperature and three different column configurations were realized experimentally. The experimental optimum values of these parameters obtained were 1.6 mol h–1, 1, 25 g and 383 K, respectively within the range of study. The butyl acetate purity of 82 % and acetic acid conversion of 80.5 % were obtained at the optimum operating conditions

    Association between First Trimester Pregnancy Associated Plasma Protein–A and the Development of Gestational Diabetes Mellitus

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    Background: Gestational diabetes (GDM) is a common pregnancy complication with significant cardiometabolic consequences for mothers and offspring. Previous research from our group suggests that adipose tissue IGFBP-5 and its unique metalloprotease PAPP-A (Pregnancy Associated Plasma Protein-A) may play mechanistic roles in GDM development by regulating functional IGF-1 levels and lipid storage and metabolism. Aim: To examine the relationship between circulating PAPP-A levels and GDM development. We hypothesized that high first trimester PAPP-A levels would be associated with decreased GDM risk. Methods: A retrospective cohort of women delivering singleton gestations at UMass Memorial Healthcare (2009, 2010, 2014, 2015) was assembled by abstracting electronic medical records. PAPP-A was measured in first trimester (11-14 weeks), and reported as quartiles of multiples of the mean (MoM) based on gestational age and adjusted for maternal weight and race/ethnicity. GDM diagnosis based on standard 2-step protocol (~24-28 weeks; failed 50g 1hr glucola screen then ≥2 abnormal values per Carpenter-Coustan criteria on 100g 3hr glucose tolerance test). Crude and multivariable-adjusted logistic regression models estimated the association between PAPP-A MoM quartiles and GDM. Results: Women (N=1,251) were 29.7 (SD:5.7) years old and 12.5 (SD:0.6) weeks gestation at PAPP-A measurement. 7.6% (n=95) developed GDM. Median PAPP-A MoM were 0.7 (inter-quartile range [IQR]=0.5-1.0) among women with GDM and 0.9 (IQR=0.6-1.3) among controls; 39% versus 23% were in the 1st quartile, respectively. After adjusting for pre-pregnancy body mass index, nuchal translucency, crown rump length, smoking status, and parity, women with PAPP-A MoM in 2nd, 3rd, and 4th quartiles had 52% (OR=0.48, 95%CI=0.26-0.88), 45% (OR=0.55, 95%CI=0.30-0.99) and 73% (OR=0.27, 95%CI=0.13-0.53) lower odds of GDM compared to women in the 1st quartile. Conclusion: Higher PAPP-A MoM levels were associated with lower GDM risk. Future studies will assess whether higher PAPP-A levels are associated with enhanced IGF-1 signaling and improved pregnancy metabolic homeostasis

    Association between First Trimester Pregnancy Associated Plasma Protein–A (PAPP-A) and Gestational Diabetes Mellitus Development

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    Background: Gestational diabetes (GDM) is a common pregnancy complication with significant cardiometabolic consequences for mothers and offspring. Previous research from our group suggests that adipose tissue IGFBP-5 and its unique metalloprotease PAPP-A (Pregnancy Associated Plasma Protein-A) may play mechanistic roles in GDM development by regulating functional IGF-1 levels and lipid storage and metabolism. Aim: To examine the relationship between circulating PAPP-A levels and GDM development. We hypothesized that high first trimester PAPP-A levels would be associated with decreased GDM risk. Methods: A retrospective cohort of women delivering singleton gestations at UMass Memorial Healthcare (2009, 2010, 2014, 2015) was assembled by abstracting electronic medical records. PAPP-A was measured in first trimester (11-14 weeks), and reported as quartiles of multiples of the mean (MoM) based on gestational age and adjusted for maternal weight and race/ethnicity. GDM diagnosis based on standard 2-step protocol (~24-28 weeks; failed 50g 1hr glucola screen then ≥2 abnormal values per Carpenter-Coustan criteria on 100g 3hr glucose tolerance test). Crude and multivariable-adjusted logistic regression models estimated the association between PAPP-A MoM quartiles and GDM. Results: Women (N=1,251) were 29.7 (SD:5.7) years old and 12.5 (SD:0.6) weeks gestation at PAPP-A measurement. 7.6% (n=95) developed GDM. Median PAPP-A MoM were 0.7 (inter-quartile range [IQR]=0.5-1.0) among women with GDM and 0.9 (IQR=0.6-1.3) among controls; 39% versus 23% were in the 1st quartile, respectively. After adjusting for pre-pregnancy body mass index, nuchal translucency, crown rump length, smoking status, and parity, women with PAPP-A MoM in 2nd, 3rd, and 4th quartiles had 52% (OR=0.48, 95%CI=0.26-0.88), 45% (OR=0.55, 95%CI=0.30-0.99) and 73% (OR=0.27, 95%CI=0.13-0.53) lower odds of GDM compared to women in the 1st quartile. Conclusion: Higher PAPP-A MoM levels were associated with lower GDM risk. Future studies will assess whether higher PAPP-A levels are associated with enhanced IGF-1 signaling and improved pregnancy metabolic homeostasis

    Bioimpedance-Based Heart Failure Deterioration Prediction Using a Prototype Fluid Accumulation Vest-Mobile Phone Dyad: An Observational Study

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    BACKGROUND: Recurrent heart failure (HF) events are common in patients discharged after acute decompensated heart failure (ADHF). New patient-centered technologies are needed to aid in detecting HF decompensation. Transthoracic bioimpedance noninvasively measures pulmonary fluid retention. OBJECTIVE: The objectives of our study were to (1) determine whether transthoracic bioimpedance can be measured daily with a novel, noninvasive, wearable fluid accumulation vest (FAV) and transmitted using a mobile phone and (2) establish whether an automated algorithm analyzing daily thoracic bioimpedance values would predict recurrent HF events. METHODS: We prospectively enrolled patients admitted for ADHF. Participants were trained to use a FAV-mobile phone dyad and asked to transmit bioimpedance measurements for 45 consecutive days. We examined the performance of an algorithm analyzing changes in transthoracic bioimpedance as a predictor of HF events (HF readmission, diuretic uptitration) over a 75-day follow-up. RESULTS: We observed 64 HF events (18 HF readmissions and 46 diuretic uptitrations) in the 106 participants (67 years; 63.2%, 67/106, male; 48.1%, 51/106, with prior HF) who completed follow-up. History of HF was the only clinical or laboratory factor related to recurrent HF events (P=.04). Among study participants with sufficient FAV data (n=57), an algorithm analyzing thoracic bioimpedance showed 87% sensitivity (95% CI 82-92), 70% specificity (95% CI 68-72), and 72% accuracy (95% CI 70-74) for identifying recurrent HF events. CONCLUSIONS: Patients discharged after ADHF can measure and transmit daily transthoracic bioimpedance using a FAV-mobile phone dyad. Algorithms analyzing thoracic bioimpedance may help identify patients at risk for recurrent HF events after hospital discharge. Sert Kuniyoshi, Joseph Rock, Theo E Meyer, David D McManus. Originally published in JMIR Cardio (http://cardio.jmir.org), 13.03.2017

    Detecting Heart Failure Decompensation by Measuring Transthoracic Bioimpedance in the Outpatient Setting: Rationale and Design of the SENTINEL-HF Study

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    BACKGROUND: Recurrent hospital admissions are common among patients admitted for acute decompensated heart failure (ADHF), but identification of patients at risk for rehospitalization remains challenging. Contemporary heart failure (HF) management programs have shown modest ability to reduce readmissions, partly because they monitor signs or symptoms of HF worsening that appear late during decompensation. Detecting early stages of HF decompensation might allow for immediate application of effective HF therapies, thereby potentially reducing HF readmissions. One of the earliest indicators of HF decompensation is intrathoracic fluid accumulation, which can be assessed using transthoracic bioimpedance. OBJECTIVE: The SENTINEL-HF study is a prospective observational study designed to test a novel, wearable HF monitoring system as a predictor of HF decompensation among patients discharged after hospitalization for ADHF. METHODS: SENTINEL-HF tests the hypothesis that a decline in transthoracic bioimpedance, as assessed daily with the Philips fluid accumulation vest (FAV) and transmitted using a mobile phone, is associated with HF worsening and rehospitalization. According to pre-specified power calculations, 180 patients admitted with ADHF are enrolled. Participants transmit daily self-assessments using the FAV-mobile phone dyad for 45 days post-discharge. The primary predictor is the deviation of transthoracic bioimpedance for 3 consecutive days from a patient-specific normal variability range. The ADHF detection algorithm is evaluated in relation with a composite outcome of HF readmission, diuretic up-titration, and self-reported HF worsening (Kansas City Cardiomyopathy Questionnaire) during a 90-day follow-up period. Here, we provide the details and rationale of SENTINEL-HF. RESULTS: Enrollment in the SENTINEL-HF study is complete and the 90-days follow-up is currently under way. Once data collection is complete, the study dataset will be used to evaluate our ADHF detection algorithm and the results submitted for publication. CONCLUSION: SENTINEL-HF emerged from our long-term vision that advanced home monitoring technology can improve the management of chronic HF by extending clinical care into patients\u27 homes. Monitoring transthoracic bioimpedance with the FAV may identify patients at risk of recurrent HF decompensation and enable timely preventive measures. TRIAL REGISTRATION: Clinicaltrials.gov NCT01877369: https://clinicaltrials.gov/ct2/show/NCT01877369 (Archived by WebCite at http://www.webcitation.org/6bDYl0dGy)

    Transthoracic Bioimpedance Monitoring Predicts Heart Failure Decompensation and Early Readmission after Heart Failure Hospitalization: Preliminary Data from SENTINEL-HF

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    Background: Patients, providers, and health systems are focused on reducing readmissions for patients with acute decompensated heart failure (ADHF). Readmission after hospitalization is common and often secondary to HF decompensation, but it remains challenging to identify patients at-risk. Bioimpedance is a validated marker of thoracic fluid accumulation. We examined whether transthoracic bioimpedance, measured using a Fluid Accumulation Vest (FAV), predicted HF decompensation in advance of a clinical event in patients discharged after ADHF. Methods: Participants included 42 patients hospitalized for ADHF. Participants were trained on the use of a FAV-smartphone dyad to obtain and transmit a 5-minute bioimpedance measurement once daily for 45-days after discharge. Readmission and diuretic dosing adjustments were identified using participant report and causes adjudicated using medical records. Receiver operating characteristic (ROC) curves and C-statistics were calculated to describe the characteristics of a bioimpedance based algorithm as a predictor of HF decompensation 3 or 7-days in advance of the clinical event. Results: Participants (mean age 69 ± 12 years, 43% female, 88% white, 11% cognitively impaired, 12% depressed) had a mean ejection fraction of 50 ± 18%. HF-related rehospitalization occurred in 10% (n=4) and 10% (n=4) reported diuretic up-titration during the 45-day follow-up. An algorithm analyzing bioimpedance up to 3 or 7 days prior to an event was related to HF readmission (C statistics for 3 and 7 days = 0.83, 0.94, respectively) and the combined outcome of HF hospitalization or diuretic up-titration (C statistics for 3 and 7 days = 0.76, 0.80, respectively). Conclusions: Early readmission after hospitalization for ADHF was common and predicted up to 7 days in advance by an algorithm analyzing transthoracic bioimpedance. Despite their advanced age and high burden of comorbid diseases, study participants with ADHF were able to make daily bioimpedance measurements using a FAV and transmit them using a smartphone. Transthoracic bioimpedance monitoring may offer possibilities for reducing HF readmissions by enabling identification and treatment of outpatients with early HF decompensation

    Assessment of low-dose cisplatin as a model of nausea and emesis in beagle dogs, potential for repeated administration

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    Cisplatin is a highly emetogenic cancer chemotherapy agent, which is often used to induce nausea and emesis in animal models. The cytotoxic properties of cisplatin also cause adverse events that negatively impact on animal welfare preventing repeated administration of cisplatin. In this study, we assessed whether a low (subclinical) dose of cisplatin could be utilized as a model of nausea and emesis in the dog while decreasing the severity of adverse events to allow repeated administration. The emetic, nausea-like behavior and potential biomarker response to both the clinical dose (70 mg/m2) and low dose (15 mg/m2) of cisplatin was assessed. Plasma creatinine concentrations and granulocyte counts were used to assess adverse effects on the kidneys and bone marrow, respectively. Nausea-like behavior and emesis was induced by both doses of cisplatin, but the latency to onset was greater in the low-dose group. No significant change in plasma creatinine was detected for either dose groups. Granulocytes were significantly reduced compared with baseline (P = 0.000) following the clinical, but not the low-dose cisplatin group. Tolerability of repeated administration was assessed with 4 administrations of an 18 mg/m2 dose cisplatin. Plasma creatinine did not change significantly. Cumulative effects on the granulocytes occurred, they were significantly decreased (P = 0.03) from baseline at 3 weeks following cisplatin for the 4th administration only. Our results suggest that subclinical doses (15 and 18 mg/m2) of cisplatin induce nausea-like behavior and emesis but have reduced adverse effects compared with the clinical dose allowing for repeated administration in crossover studies

    Enhanced He-alpha emission from "smoked" Ti targets irradiated with 400nm, 45 fs laser pulses

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    We present a study of He-like 1s(2)-1s2p line emission from solid and low-density Ti targets under similar or equal to 45 fs laser pulse irradiation with a frequency doubled Ti: Sapphire laser. By varying the beam spot, the intensity on target was varied from 10(15) W/cm(2) to 10(19) W/cm(2). At best focus, low density "smoked" Ti targets yield similar to 20 times more He-alpha than the foil targets when irradiated at an angle of 45 degrees with s-polarized pulses. The duration of He-alpha emission from smoked targets, measured with a fast streak camera, was similar to that from Ti foils
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