17 research outputs found

    Twisted Conjugacy Classes in Lattices in Semisimple Lie Groups

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    Given a group automorphism ϕ:Γ→Γ\phi:\Gamma\to \Gamma, one has an action of Γ\Gamma on itself by ϕ\phi-twisted conjugacy, namely, g.x=gxϕ(g−1)g.x=gx\phi(g^{-1}). The orbits of this action are called ϕ\phi-conjugacy classes. One says that Γ\Gamma has the R∞R_\infty-property if there are infinitely many ϕ\phi-conjugacy classes for every automorphism ϕ\phi of Γ\Gamma. In this paper we show that any irreducible lattice in a connected semi simple Lie group having finite centre and rank at least 2 has the R∞R_\infty-property.Comment: 6 page

    Fabrication Of Butterfly Pea Flower Anthocyanin-Incorporated Colorimetric Indicator Film Based On Gelatin/Pectin For Monitoring Fish Freshness

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    Novel visual intelligent pH-indicator film was prepared from the eggshell membrane- gelatin, pectin, and anthocyanin pigment from butterfly pea flower (BP) (Clitoria ternatea). It was used as a real-time pH indicator for predicting food freshness. Eggshells are useful biowaste, gelatin has been extracted from the eggshell membrane and was used for fabricating the film. The Anthocyanin content of BP extract was 198.3 mg g−1. The film's surface morphology and chemical nature were estimated using a Scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray diffraction technique. The film was pH responsive and exhibited color variation ranging from shades of red, purple, blue, green, and yellow at different pH (1-13). The applicability of the developed pH- indicator film was studied on fresh Tilapia fish by monitoring its deterioration for a specific time period. The film showed a visible color change after seven days of storage at 4ºC from dark blue, bluish-grey to olive, and deep green. Change in the total volatile basic nitrogen (TVB-N) content and pH change had an effect on the color response of the film. The findings demonstrated that the fabricated pH indicator film proved to be pH sensitive and could be used to monitor fish freshness

    Searching for the Cat: Effects of variable spatial associations on search in scenes

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    Some objects have a specific place where you can expect them to be found (e.g., toothbrush), while others vary wildly in the places that they can appear (e.g., cat). While previous studies have pointed to the importance of the spatial associations in search in scenes, in the current study we investigated the effects of the variability of expected spatial locations of target objects on search performance. On each trial, participants’ eye movements were tracked while they searched for either a Fixed Target, which was associated with a specific scene surface (e.g., boots) or a Variable Target, which was not associated with a specific region (cat). Results showed not only a slower search performance for variable than fixed targets, but also a longer latency and many more fixations to locate Variable than Fixed targets. We also explored the effect of placement within the scene and found that the effects differed depending on the surface location. Findings demonstrates that the variability of targets’ spatial associations affected search efficiency as well as provided new insights into how search strategies are implemented in the face of uncertainty

    Use of Sodium Bicarbonate During Pediatric Cardiac Admissions with Cardiac Arrest: Who Gets It and What Does It Do?

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    The objectives of this study were to characterize the use of sodium bicarbonate in pediatric cardiac admissions that experience cardiac arrest, to determine sodium bicarbonate use over the years, and to determine the impact of sodium bicarbonate on length of admissions, billed charges, and inpatient mortality. A cross-sectional study was conducted utilizing the Pediatric Health Information System database. Characteristics of admissions with and without sodium bicarbonate were initially compared by univariate analyses. The frequency by which sodium bicarbonate was used was compared by year. Regression analyses were conducted to determine the impact of sodium bicarbonate on length of stay, billed charges, and inpatient mortality. A total of 3987 (50.3%) of pediatric cardiac intensive care admissions with cardiac arrest utilized sodium bicarbonate; however, frequency changed from 62.1% in 2004 to 43.7% in 2015. Linear regression analysis demonstrated a decrease in length of stay (−27.5 days, p < 0.01) and billed charges (−$470,906, p < 0.01). Logistic regression analysis demonstrated an increase in mortality (odds ratio 1.77, 95% confidence interval 1.56–2.01). In conclusion, sodium bicarbonate is being used with less frequency over the last years in pediatric cardiac admissions with cardiac arrest. After adjustment for cardiac diagnoses, comorbidities, vasoactive medications, and other resuscitation medications, sodium bicarbonate is independently associated with increased mortality

    Impact of sodium bicarbonate therapy on hemodynamic parameters in infants: a meta-analysis

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    Objective: Sodium bicarbonate is a frequently used electrolyte for the acute treatment of metabolic acidosis in critically ill patients. We performed a systematic review and meta-analysis to determine the effect of sodium bicarbonate on hemodynamics, gas exchange and oximetry in critically children. Methods: A systematic review of published manuscripts was conducted to identify studies of children who received sodium bicarbonate as part of the treatment for metabolic acidosis. A meta-analysis was then conducted to determine the impact of sodium bicarbonate on hemodynamics, gas exchange and oximetry. The following parameters were captured: base deficit, heart rate, mean arterial pressure, blood concentration of carbon dioxide, blood concentration of hydrogen ion, and pulse oximetry. Results: A total of six studies with 341 patients were included in the analyses. All included studies were completed in critically ill infants with a mean age of 1.1 months. The mean dose of sodium bicarbonate was 1.7 meq/kg with a mean time of 67 min prior to repeat hemodynamics being collected after sodium bicarbonate administration. Base deficit significantly improved with a decrease of 2.80 (p = .001) and the partial pressure of carbon dioxide significantly decreased by a mean of -1.65 mmHg (p = .010). There was no change in heart rate, blood pressure, pH, partial pressure of oxygen, or saturation by pulse oximetry. Conclusion: Sodium bicarbonate has a statistically significant but not clinically significant impact on partial pressure of carbon dioxide and base deficit 60 min after sodium bicarbonate administration in critically ill infants. There is no difference noted in pH, partial pressure of oxygen, or saturation by pulse oximetry

    The progress and significance of QRS duration by electrocardiography in hypoplastic left heart syndrome

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    Patients with hypoplastic left heart syndrome (HLHS) are now surviving through to Fontan palliation and beyond, however, with increased morbidity and mortality. Prolonged QRSd has become one of the predictors of morbidity and mortality in certain congenital heart diseases. There is limited data characterizing the QRSd in patients with HLHS. We aimed to describe the changes in QRSd at various times during the lifetime and to evaluate whether QRSd correlates with a higher risk of developing a composite endpoint of heart failure, heart transplant, or death. We conducted a retrospective chart review of patients with HLHS who survived Fontan palliation. QRSd was measured on ECGs at various stages pre- and postsurgical palliations and subsequently at 5 year intervals. Patients with a composite endpoint were compared to those without. A total of 89 patients were included in the final analysis. The QRSd increased significantly with time from 68.7 ± 9.0 ms prior to Norwood to 91.0 ± 14.0 ms immediately following Fontan and 104.7 ± 13.6 ms 15 years after Fontan (p \u3c 0.001). The composite endpoint was observed in 28 patients (31.4%). The time trends of QRSd differ so that the patients having the composite endpoint experienced a greater increase in QRSd over time (p = 0.009). Ever having a QRSd of 120 ms or more predicted the composite endpoint with 93% specificity. The area under the curve of the receiver operator curve analysis was 0.596. A Cox regression analysis demonstrated that QRS duration \u3e 120 ms was independently related to a greater frequency of composite endpoint and this was confirmed by a Kaplan-Meier analysis (p = 0.011). This study unveils a novel relationship between QRSd of 120 ms or more with the composite endpoint. Despite the low sensitivity, this finding on a routine surveillance ECG could help identify HLHS Fontan patients at risk for heart failure, heart transplant, or death

    Echocardiographic strain to predict need for transplant or mortality in Fontan patients with hypoplastic left heart syndrome

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    Despite recent advances, hypoplastic left heart syndrome (HLHS) patients subsequent to the Fontan still have significant morbidity and mortality. Some require heart transplant due to systemic ventricular dysfunction. Limited data exist on timing for transplant referral. This study aims to correlate systemic ventricular strain by echocardiography to transplant-free survival. HLHS patients who had Fontan palliation at our institution were included. Patients were divided into: 1) Required transplant or experienced mortality (composite end point); 2) Did not require transplant or survived. For those who experienced the composite endpoint, the last echocardiogram prior to the composite outcome was used, while for those who did not experience the composite endpoint the last echocardiogram obtained was used. Several qualitative and quantitative parameters were analyzed with focus on strain parameters. Ninety-five patients with HLHS Fontan palliation were identified. Sixty-six had adequate images and eight (12%) experienced transplant or mortality. These patients had greater myocardial performance index by flow Doppler (0.72 versus 0.53, p = 0.01), higher systolic/diastolic duration ratio (1.51 versus 1.13, p = 0.02), lower fractional area change (17.65 versus 33.99, p \u3c 0.01), lower global longitudinal strain (GLS) (-8.63 versus - 17.99, p \u3c 0.01), lower global longitudinal strain rate (GLSR) (- 0.51 versus - 0.93, p \u3c 0.01), lower global circumferential strain (GCS) (-6.68 versus -18.25, p \u3c 0.01), and lower (GCSR) global circumferential strain rate (-0.45 versus -1.01, p \u3c 0.01). ROC analysis demonstrated predictive value for GLS - 7.6 (71% sensitive, 97% specific, AUC 81%), GLSR -0.58 (71% sensitive, 88% specific, AUC 82%), GCS - 10.0 (86% sensitive, 91% specific, AUC 82%), and GCSR -0.85 (100% sensitive, 71% specific, AUC 90%). GLS and GCS can help predict transplant-free survival in patients with hypoplastic left heart syndrome having undergone Fontan palliation. Higher strain values (closer to zero) may be a helpful tool in determining when transplant evaluation is warranted in these patients

    Energy availability and the female athlete trial in elite endurance athletes

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    The female athlete triad (Triad), links low energy availability (EA), with menstrual dysfunction (MD), and impaired bone health. The aims of this study were to examine associations between EA/MD and energy metabolism and the prevalence of Triad-associated conditions in endurance athletes. Forty women [26.2 +/- 5.5 years, body mass index (BMI) 20.6 +/- 2.0 kg/m(2), body fat 20.0 +/- 3.0%], exercising 11.4 +/- 4.5 h/week, were recruited from national teams and competitive clubs. Protocol included gynecological examination; assessment of bone health; indirect respiratory calorimetry; diet and exercise measured 7 days to assess EA; eating disorder (ED) examination; blood analysis. Subjects with low/reduced EA (< 45 kcal/kg FFM/day), had lower resting metabolic rate (RMR) compared with those with optimal EA [28.4 +/- 2.0 kcal/kg fat-free mass (FFM)/day vs 30.5 +/- 2.2 kcal/kg FFM/day, P < 0.01], as did subjects with MD compared with eumenorrheic subjects (28.6 +/- 2.4 kcal/kg FFM/day vs 30.2 +/- 1.8 kcal/kg FFM/day, P < 0.05). 63% had low/reduced EA, 25% ED, 60% MD, 45% impaired bone health, and 23% had all three Triad conditions. 53% had low RMR, 25% hypercholesterolemia, and 38% hypoglycemia. Conclusively, athletes with low/reduced EA and/or MD had lowered RMR. Triad-associated conditions were common in this group of athletes, despite a normal BMI range. The high prevalence of ED, MD, and impaired bone health emphasizes the importance of prevention, early detection, and treatment of energy deficiency

    Circulating miRNAs in Women with Polycystic Ovary Syndrome: A Longitudinal Cohort Study

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    Background: Women with polycystic ovary syndrome (PCOS) often change their metabolic profile over time to decrease levels of androgens while often gaining a propensity for the development of the metabolic syndrome. Recent discoveries indicate that microRNAs (miRNAs) play a role in the development of PCOS and constitute potential biomarkers for PCOS. We aimed to identify miRNAs associated with the development of an impaired metabolic profile in women with PCOS, in a follow-up study, compared with women without PCOS. Methods and materials: Clinical measurements of PCOS status and metabolic disease were obtained twice 6 years apart in a cohort of 46 women with PCOS and nine controls. All participants were evaluated for degree of metabolic disease (hypertension, dyslipidemia, central obesity, and impaired glucose tolerance). MiRNA levels were measured using Taqman® Array cards of 96 pre-selected miRNAs associated with PCOS and/or metabolic disease. Results: Women with PCOS decreased their levels of androgens during follow-up. Twenty-six of the miRNAs were significantly changed in circulation in women with PCOS during the follow-up, and twenty-four of them had decreased, while levels did not change in the control group. Four miRNAs were significantly different at baseline between healthy controls and women with PCOS; miR-103-3p, miR-139-5p, miR-28-3p, and miR-376a-3p, which were decreased in PCOS. After follow-up, miR-28-3p, miR-139-5p, and miR-376a-3p increased in PCOS women to the levels observed in healthy controls. Of these, miR-139-5p correlated with total testosterone levels (rho = 0.50, padj = 0.013), while miR-376-3p correlated significantly with the waist-hip ratio at follow-up (rho = 0.43, padj = 0.01). Predicted targets of miR-103-3p, miR-139-5p, miR-28-3p, and miR-376a-3p were enriched in pathways associated with Insulin/IGF signaling, interleukin signaling, the GNRH receptor pathways, and other signaling pathways. MiRNAs altered during follow-up in PCOS patients were enriched in pathways related to immune regulation, gonadotropin-releasing hormone signaling, tyrosine kinase signaling, and WNT signaling. Conclusions: These studies indicate that miRNAs associated with PCOS and androgen metabolism overall decrease during a 6-year follow-up, reflecting the phenotypic change in PCOS individuals towards a less hyperandrogenic profile
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