Search results for: blood glucose concentration
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 7454

Search results for: blood glucose concentration

6194 The Comparison between Modelled and Measured Nitrogen Dioxide Concentrations in Cold and Warm Seasons in Kaunas

Authors: A. Miškinytė, A. Dėdelė

Abstract:

Road traffic is one of the main sources of air pollution in urban areas associated with adverse effects on human health and environment. Nitrogen dioxide (NO2) is considered as traffic-related air pollutant, which concentrations tend to be higher near highways, along busy roads and in city centres and exceedances are mainly observed in air quality monitoring stations located close to traffic. Atmospheric dispersion models can be used to examine emissions from many various sources and to predict the concentration of pollutants emitted from these sources into the atmosphere. The study aim was to compare modelled concentrations of nitrogen dioxide using ADMS-Urban dispersion model with air quality monitoring network in cold and warm seasons in Kaunas city. Modelled average seasonal concentrations of nitrogen dioxide for 2011 year have been verified with automatic air quality monitoring data from two stations in the city. Traffic station is located near high traffic street in industrial district and background station far away from the main sources of nitrogen dioxide pollution. The modelling results showed that the highest nitrogen dioxide concentration was modelled and measured in station located near intensive traffic street, both in cold and warm seasons. Modelled and measured nitrogen dioxide concentration was respectively 25.7 and 25.2 µg/m3 in cold season and 15.5 and 17.7 µg/m3 in warm season. While the lowest modelled and measured NO2 concentration was determined in background monitoring station, respectively 12.2 and 13.3 µg/m3 in cold season and 6.1 and 7.6 µg/m3 in warm season. The difference between monitoring station located near high traffic street and background monitoring station showed that better agreement between modelled and measured NO2 concentration was observed at traffic monitoring station.

Keywords: air pollution, nitrogen dioxide, modelling, ADMS-Urban model

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6193 The Effect of Santolina Plant Extract on Nitro-Oxidative Stress

Authors: Sabrina Sebbane, Alina Elena Parvu

Abstract:

Introduction: Santolina rosmarinifolia is a plant of the Santolina genus, a family made of medicinal plants widely used. Some of the Santolina species have been proven to have potent anti-inflammatory and anti-oxidant effects. However, no in vivo study has been made to demonstrate this in Santolina rosmarinifolia. The aim of our study is to experimentally evaluate the potential anti-inflammatory and anti-oxidant effects of Santolina rosmarinifolia plant extracts on acute inflammation in rats. These effects are defined by measuring the modifications on nitric oxide, reactive oxygen species and anti-oxidant response in serum. Materials and Methods: Rats were divided into 5 groups (n=6). Three groups were given Santolina rosmarinifolia extract by gavage in different concentrations(100%, 50%, 25%) for a week. Inflammation was induced by i.m injection of turpentine oil on the 8th day. One group was only given turpentine oil and the fifth group acted as control and was given only saline solution. Blood was collected and serum separated. Global tests were used to measure the oxidative stress, total oxidative status (TOS), total antioxidant reactivity (TAR) and the modified method of Griess assay to measure NO synthesis. Malondilaldehyde (MDA) and thiols levels were also assessed. Results: Santolina rosmarinifolia did not significantly change the TOS levels (p > 0.05). Santolina rosmarinifolia 25% and 50% decreased significantly the TAR levels (p < 0.001). Santolina 100% didn't have a significant effect on TAR (p > 0.05). All concentrations of Santolina rosmarinifolia increased the oxidative stress index (OSI) significantly(p < 0.05). Santolina rosmarinifolia 100% significantly decreased NO synthesis (p value < 0.05). In the diluted Santolina groups, no significant effect on NO synthesis was observed. In the groups treated with Santolina 100% and Santolina rosmarinifolia 50%, thiols concentration were significantly higher compared to the inflammation group (p < 0.02). A higher stimulatory effect was found in the Santolina 25% group (p value < 0.05). MDA levels were not significantly modified by the administration of Santolina rosmarinifolia (p > 0.05). Conclusion: All three solutions of Santolina rosmarinifolia had no important effect on oxidant production. However, Santolina rosmarinifolia solutions had a positive effect by increasing the thiols concentration in the serum of the models. The sum of all the effects produced by the administration of Santolina did not show a significant decrease of nitro-oxidative stress. Further experiments including smaller concentrations of Santolina rosmarinifolia will be made. Santolina rosmarinifolia should also be tested as a curative treatment.

Keywords: inflammation, MDA, nitric oxide, santolina rosmarinifolia, thiols, TAR, TOS

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6192 Structural, Magnetic and Electrical Properties of Gd3+ Doped CoFe2O4 Nanoparticles Synthesized by Sonochemical Method

Authors: Raghvendra Singh Yadav, Ivo Kuřitka

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In this report, we studied the impact of Gd3+ substitution on structural, magnetic and electrical properties of CoFe2O4 nanoparticles synthesized by sonochemical method. X-ray diffraction pattern confirmed the formation of cubic spinel structure at low concentration of Gd3+ ions, however, GdFeO3 additional phase was observed at higher concentration of Gd3+ ions. Raman and Fourier Transform Infrared spectroscopy study also confirmed cubic spinel structure of Gd3+ substituted CoFe2O4 nanoparticles. The field emission scanning electron microscopy study revealed that Gd3+ substituted CoFe2O4 nanoparticles were in the range of 5-20 nm. The magnetic properties of Gd3+ substituted CoFe2O4 nanoparticles were investigated by using vibrating sample magnetometer. The variation in saturation magnetization, coercivity and remanent magnetization with Gd3+ concentration in CoFe2O4 nanoparticles was observed. The variation of real and imaginary part of dielectric constant, tan δ, and AC conductivity were studied at room temperature.

Keywords: spinel ferrites, nanoparticles, sonochemical method, magnetic properties

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6191 Photo Catalytic Treatment of Wastewater from Processing Poultry by-Products

Authors: J. Franco Macías, E. Montes Alba, A. López Vásquez

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The growing development in the poultry industry has generated a strong and adverse impact on quality and availability of water resources. Inside this industry, is finding out the treatment of by-products such as feathers, viscera and blood demanding highly water consumption, generating contaminant discharges as well. As one of current of treatment of by-products is the effluent of cooking condensate steam that has contaminant organic load; therefore, it is necessary to implement removal treatments before discharging it toward water sources. The photo catalysis appears as a promising alternative of treatment due to the different advantages it has, among others, includes low cost, easily operation, high efficiency and elimination of a wide variety of contaminants in a watery environment. This study has evaluated a heterogeneous photo catalytic treatment for removal contaminant organic load. This process was developed in oxidation and reduction conditions. It was analyzed the effect of factors such as pH, catalyst and sacrifice agent concentration. Finally, good conditions to removal contaminant organic load were achieved to determine percentage of contaminant organic load by means of response surface methodology.

Keywords: poultry industry, advanced oxidation process, photocatalysis, photodegradation, TiO2

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6190 [Keynote Talk]: Mathematical and Numerical Modelling of the Cardiovascular System: Macroscale, Mesoscale and Microscale Applications

Authors: Aymen Laadhari

Abstract:

The cardiovascular system is centered on the heart and is characterized by a very complex structure with different physical scales in space (e.g. micrometers for erythrocytes and centimeters for organs) and time (e.g. milliseconds for human brain activity and several years for development of some pathologies). The development and numerical implementation of mathematical models of the cardiovascular system is a tremendously challenging topic at the theoretical and computational levels, inducing consequently a growing interest over the past decade. The accurate computational investigations in both healthy and pathological cases of processes related to the functioning of the human cardiovascular system can be of great potential in tackling several problems of clinical relevance and in improving the diagnosis of specific diseases. In this talk, we focus on the specific task of simulating three particular phenomena related to the cardiovascular system on the macroscopic, mesoscopic and microscopic scales, respectively. Namely, we develop numerical methodologies tailored for the simulation of (i) the haemodynamics (i.e., fluid mechanics of blood) in the aorta and sinus of Valsalva interacting with highly deformable thin leaflets, (ii) the hyperelastic anisotropic behaviour of cardiomyocytes and the influence of calcium concentrations on the contraction of single cells, and (iii) the dynamics of red blood cells in microvasculature. For each problem, we present an appropriate fully Eulerian finite element methodology. We report several numerical examples to address in detail the relevance of the mathematical models in terms of physiological meaning and to illustrate the accuracy and efficiency of the numerical methods.

Keywords: finite element method, cardiovascular system, Eulerian framework, haemodynamics, heart valve, cardiomyocyte, red blood cell

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6189 Growth of Non-Polar a-Plane AlGaN Epilayer with High Crystalline Quality and Smooth Surface Morphology

Authors: Abbas Nasir, Xiong Zhang, Sohail Ahmad, Yiping Cui

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Non-polar a-plane AlGaN epilayers of high structural quality have been grown on r-sapphire substrate by using metalorganic chemical vapor deposition (MOCVD). A graded non-polar AlGaN buffer layer with variable aluminium concentration was used to improve the structural quality of the non-polar a-plane AlGaN epilayer. The characterisations were carried out by high-resolution X-ray diffraction (HR-XRD), atomic force microscopy (AFM) and Hall effect measurement. The XRD and AFM results demonstrate that the Al-composition-graded non-polar AlGaN buffer layer significantly improved the crystalline quality and the surface morphology of the top layer. A low root mean square roughness 1.52 nm is obtained from AFM, and relatively low background carrier concentration down to 3.9×  cm-3 is obtained from Hall effect measurement.

Keywords: non-polar AlGaN epilayer, Al composition-graded AlGaN layer, root mean square, background carrier concentration

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6188 The Determination of Sodium/Potassium Ion Ratio in Selected Edible Leafy Vegetables in North-Eastern Nigeria

Authors: Raymond D. Uzoh, Philip K. Shallsuku, Christopher S. Vaachia

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Selected edible leafy vegetables from North-eastern Nigeria were analysed for their sodium and potassium content in mg/100 g and the ratio Na+/K+ worked out. From experimental results, Venonia amydalina (bitter leaf) contained 150 mg (0.15 g) of sodium and 20500 mg (20.5 g) potassium with a ratio of 0.007, Brassica oleracea var capitata (cabbage) contained 300 mg (0.3 g) of sodium and 19000 mg (19 g) of potassium with a ration of 0.012. Others are Telfairia occidentalis (fluted pumpkin) with 400 mg (0.45 g) of sodium and 19500 mg (19.5 g) of potassium with a ratio of 0.020; Hibiscus sabdriffa (sorrel) has 200 mg (0.2 g) of sodium and 600 mg (0.6 g) of potassium with a ratio of 0.300; and Amarantus caudatus (spinach) contained 450 mg (0.45 g) of sodium and 23000 mg (23 g) of potassium with a ratio of 0.020. The presence of sodium and potassium in foods has become increasingly important as recent studies and dietary information gathered in this research has shown that sodium intake is not the sole consideration in elevated blood pressure but its considered as a ratio Na+/K+ fixed at 0.6. This ratio has been found to be a more important factor, suggesting that our diet should contain 67 % more potassium than sodium.

Keywords: vegetables, sodium, potassium, blood pressure, diet, foods

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6187 Emergency Department Utilisation of Older People Presenting to Four Emergency Departments

Authors: M. Fry, L. Fitzpatrick, Julie Considine, R. Z. Shaban, Kate Curtis

Abstract:

Introduction: The vast majority of older Australians lives independently and are self-managing at home, despite a growing number living with a chronic illness that requires health intervention. Evidence shows that between 50% and 80% of people presenting to the emergency department (ED) are in pain. Australian EDs manage 7.2 million attendances every year and 1.4 million of these are people aged 65 years or more. Research shows that 28% of ED patients aged 65 years or more have Cognitive impairment (CI) associated with dementia, delirium and neurological conditions. Background: Traditional ED service delivery may not be suitable for older people who present with multiple, complex and ongoing illnesses. Likewise, ED clinical staff often perceive that their role should be focused more on immediate and potential lifethreatening illness and conditions which are episodic in nature. Therefore, the needs of older people and their family/carers may not be adequately addressed in the context of an ED presentation. Aim: We aimed to explore the utilisation and characteristics of older people presenting to four metropolitan EDs. Method: The findings being presented are part of a program of research exploring pain management practices for older persons with long bone fractures. The study was conducted across four metropolitan emergency departments of older patients (65years and over) and involved a 12-month randomised medical record audit (n=255). Results: ED presentations across four ED sites in 2012 numbered 168021, with 44778 (26.6%) patients aged 65 and over. Of the 44778 patients, the average age was 79.1 years (SD 8.54). There were more females 23932 (53.5%). The majority (26925: 85.0%) of older persons self-referred to the ED and lived independently. The majority arrived by ambulance (n=18553: 41.4%) and were allocated triage category was 3 (n=19,507:43.65%) or Triage category 4 at (n=15,389: 34.43%). The top five triage symptom presentations involved pain (n=8088; 18.25%), dyspnoea (n=4735; 10.7%), falls (n=4032; 9.1%), other (n=3984; 9.0%), cardiac (n=2987; 6.7%). The top five system based diagnostic presentations involved musculoskeletal (n=8902; 20.1%), cardiac (n=6704:15.0%), respiratory (n=4933; 11.0%), neurological (n=4909; 11.0%), gastroenterology (n=4321; 9.7%). On review of one tertiary hospital database the vital signs on average at time triage: Systolic Blood Pressure 143.6mmHg. Heart Rate 83.4 beats/minute; Respiratory Rate 18.5 breaths/ minute; Oxygen saturation 97.0% and Tympanic temperature 36.7 and Blood Glucose Level 7.4mmols/litre. The majority presented with a Glasgow Coma Score of 14 or higher. On average the older person stayed in the ED 4:56 (SD 3:28minutes).The average time to be seen was 39 minutes (SD 48 minutes). The majority of older persons were admitted (n=27562: 61.5%), did not wait for treatment (n= 8879: 0.02%) discharged home (n=16256: 36.0%). Conclusion: The vast majority of older persons are living independently, although many require admission on arrival to the ED. Many arrived in pain and with musculoskeletal injuries and or conditions. New models of care need to be considered, which may better support self-management and independent living of the older person and the National Emergency Access Targets.

Keywords: chronic, older person, aged care, emergency department

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6186 Study of Quantum Lasers of Random Trimer Barrier AlxGa1-xAs Superlattices

Authors: Bentata Samir, Bendahma Fatima

Abstract:

We have numerically studied the random trimer barrier AlxGa1-xAs superlattices (RTBSL). Such systems consist of two different structures randomly distributed along the growth direction, with the additional constraint that the barriers of one kind appear in triply. An explicit formula is given for evaluating the transmission coefficient of superlattices (SL's) in intentional correlated disorder. We have specially investigated the effect of aluminum concentration on the laser wavelength. We discuss the impact of the aluminum concentration associated with the structure profile on the laser wavelengths.

Keywords: superlattices, transfer matrix method, transmission coefficient, quantum laser

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6185 Synergistic Effect of Curcumin and Insulin on GLUT4 Translocation in C2C12 Cell

Authors: Javad Mohiti-Ardekani, Shabodin Asadii, Ali Moradi

Abstract:

Introduction: Curcumin, the yellow pigment in turmeric, has been shown as an anti-diabetic agent for centuries but only in recent few years, its mechanism of action has been under investigation. Some studies showed that curcumin might exert its anti-diabetic effect via increasing glucose transporter isotype-4 (GLUT4) gene and glycoprotein contents in cells. To investigate this possibility, we investigate the effects of extract and commercial curcumin with and without insulin on GLUT4 translocation from intracellular compartments of nuclear or endoplasmic reticulum membranes (N/ER) into the cytoplasmic membrane (CM). Methods and Material: C2C12 myoblastic cell line were seeded in DMEM plus 20 % FBS and differentiated to myotubes using 2 % horse serum. After myotubes formation, 40 µmolar Extract and Commercial curcumin, with or without insulin as intervention, and as control 1 % DMSO were added for 3 h. Cells were washed and homogenized followed by ultracentrifuge fractionation, protein separation by SDS-PAGE and GLUT4 detection using semi-quantitative Western blotting. Data analysis was done by two independent samples t-test for comparison of mean ± SD of GLUT4 percent in categories. GLUT4 contents were higher in CM groups curcumin and curcumin with insulin in comparison to 1 % DMSO-treated myotubes control group. Results: As our results have shown extract and commercial curcumin induces GLUT4 translocation from intra-cell into cell surface. The results have also shown synergic effect of curcumin on translocation of GLUT4 from intra-cell into cell surface in the presence of 100 nm insulin. Discussion: We conclude that curcumin may be a choice of type-2 diabetes mellitus treatment because its extract and commercial enhances GLUT4 contents in CM where it facilitates glucose entrance into the cell. However, it is necessary to trace the signaling pathways which are activated by curcumin.

Keywords: Curcumin, insulin, Diabetes type-2, GLUT4

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6184 Association of Brain-Derived Neurotrophic Factor (BDNF) Gene with Obesity and Metabolic Traits in Malaysian Adults

Authors: Yamunah Devi Apalasamy, Sanjay Rampal, Tin Tin Su, Foong Ming Moy, Hazreen Abdul Majid, Awang Bulgiba, Zahurin Mohamed

Abstract:

Obesity is a growing global health issue. Obesity results from a combination of environmental and genetics factors. Brain-derived neurotrophic factor (BDNF), a gene encodes the BDNF protein and the BDNF gene have been linked to regulation of body weight and appetite. Genome-wide association studies have identified the BDNF variants to be related to obesity among Caucasians, East Asians, and Filipinos. However, the role of BDNF in other ethnic groups remains inconclusive. This case control study aims to investigate the associations of BDNF gene polymorphisms with obesity and metabolic parameters in Malaysian Malays. BDNF rs4074134, BDNF rs10501087 and BDNF rs6265 were genotyped using Sequenom MassARRAY. Anthropometric, body fat, fasting lipids and glucose levels were measured. A total of 663 subjects (194 obese and 469 non-obese) were included in this study. There were no significant associations association between BDNF SNPs and obesity. The allelic and genotype frequencies of the BDNF SNPs were similar in the obese and non-obese groups. After adjustment for age and sex, the BDNF variants were not associated with obesity, body fat, fasting lipids and glucose levels. Haplotypes at the BDNF gene region, were not significantly associated with obesity. The BDNF rs4074134 was in strong LD with BDNF rs10501087 (D'=0.98) and BDNF rs6265 (D'=0.87). The BDNF rs10501087 was also in strong LD with BDNF rs6265 (D'=0.91). Our findings suggest that the BDNF variants and the haplotypes of BDNF gene were not associated with obesity and metabolic traits in this study population. Further research is needed to explore other BDNF variants with a larger sample size with gene-environment interactions in multi ethnic Malaysian population.

Keywords: genomics of obesity, SNP, BMI, haplotypes

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6183 Heteromolecular Structure Formation in Aqueous Solutions of Ethanol, Tetrahydrofuran and Dimethylformamide

Authors: Sh. Gofurov, O. Ismailova, U. Makhmanov, A. Kokhkharov

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The refractometric method has been used to determine optical properties of concentration features of aqueous solutions of ethanol, tetrahydrofuran and dimethylformamide at the room temperature. Changes in dielectric permittivity of aqueous solutions of ethanol, tetrahydrofuran and dimethylformamide in a wide range of concentrations (0÷1.0 molar fraction) have been studied using molecular dynamics method. The curves depending on the concentration of experimental data on excess refractive indices and excess dielectric permittivity were compared. It has been shown that stable heteromolecular complexes in binary solutions are formed in the concentration range of 0.3÷0.4 mole fractions. The real and complex part of dielectric permittivity was obtained from dipole-dipole autocorrelation functions of molecules. At the concentrations of C = 0.3 / 0.4 m.f. the heteromolecular structures with hydrogen bonds are formed. This is confirmed by the extremum values of excessive dielectric permittivity and excessive refractive index of aqueous solutions.

Keywords: refractometric method, aqueous solution, molecular dynamics, dielectric constant

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6182 Potential Therapeutic Effect of Obestatin in Oral Mucositis

Authors: Agnieszka Stempniewicz, Piotr Ceranowicz, Wojciech Macyk, Jakub Cieszkowski, Beata Kuśnierz-Cabała, Katarzyna Gałązka, Zygmunt Warzecha

Abstract:

Objectives: There are numerous strategies for the prevention or treatment of oral mucositis. However, their effectiveness is limited and does not correspond to expectations. Recent studies have shown that obestatin exhibits a protective effect and accelerates the healing of gastrointestinal mucosa. The aim of the present study was to examine the influence of obestatin administration on oral ulcers in rats. Methods: lingual ulcers were induced by the use of acetic acid. Rats were treated twice a day intraperitoneally with saline or obestatin(4, 8, or 16 nmol/kg/dose) for five days. The study determined: lingual mucosa morphology, cell proliferation, mucosal blood flow, and mucosal pro-inflammatory interleukin-1β level(IL-1β). Results: In animals without induction of oral ulcers, treatment with obestatin was without any effect. Obestatin administration in rats with lingual ulcers increased the healing rate of these ulcers. Obestatin given at the dose of 8 or 16 nmol/kg/dose caused the strongest and similar therapeutic effect. This result was associated with a significant increase in blood flow and cell proliferation in gingival mucosa, as well as a significant decrease in IL-1β level. Conclusions: Obestatin accelerates the healing of lingual ulcers in rats. This therapeutic effect is well-correlated with an increase in blood flow and cell proliferation in oral mucosa, as well as a decrease in pro-inflammatory IL-1β levels. Obestatin is a potentially useful candidate for the prevention and treatment of oral mucositis. Acknowledgment: Agnieszka Stempniewicz acknowledges the support of InterDokMed project no. POWR.03.02.00- 00-I013/16.

Keywords: oral mucositis, ulcers, obestatin, lingual mucosa

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6181 Predicting Factors for Occurrence of Cardiac Arrest in Critical, Emergency and Urgency Patients in an Emergency Department

Authors: Angkrit Phitchayangkoon, Ar-Aishah Dadeh

Abstract:

Background: A key aim of triage is to identify the patients with high risk of cardiac arrest because they require intensive monitoring, resuscitation facilities, and early intervention. We aimed to identify the predicting factors such as initial vital signs, serum pH, serum lactate level, initial capillary blood glucose, and Modified Early Warning Score (MEWS) which affect the occurrence of cardiac arrest in an emergency department (ED). Methods: We conducted a retrospective data review of ED patients in an emergency department (ED) from 1 August 2014 to 31 July 2016. Significant variables in univariate analysis were used to create a multivariate analysis. Differentiation of predicting factors between cardiac arrest patient and non-cardiac arrest patients for occurrence of cardiac arrest in an emergency department (ED) was the primary outcome. Results: The data of 527 non-trauma patients with Emergency Severity Index (ESI) 1-3 were collected. The factors found to have a significant association (P < 0.05) in the non-cardiac arrest group versus the cardiac arrest group at the ED were systolic BP (mean [IQR] 135 [114,158] vs 120 [90,140] mmHg), oxygen saturation (mean [IQR] 97 [89,98] vs 82.5 [78,95]%), GCS (mean [IQR] 15 [15,15] vs 11.5 [8.815]), normal sinus rhythm (mean 59.8 vs 30%), sinus tachycardia (mean 46.7 vs 21.7%), pH (mean [IQR] 7.4 [7.3,7.4] vs 7.2 [7,7.3]), serum lactate (mean [IQR] 2 [1.1,4.2] vs 7 [5,10.8]), and MEWS score (mean [IQR] 3 [2,5] vs 5 [3,6]). A multivariate analysis was then performed. After adjusting for multiple factors, ESI level 2 patients were more likely to have cardiac arrest in the ER compared with ESI 1 (odds ratio [OR], 1.66; P < 0.001). Furthermore, ESI 2 patients were more likely than ESI 1 patients to have cardiovascular disease (OR, 1.89; P = 0.01), heart rate < 55 (OR, 6.83; P = 0.18), SBP < 90 (OR, 3.41; P = 0.006), SpO2 < 94 (OR, 4.76; P = 0.012), sinus tachycardia (OR, 4.32; P = 0.002), lactate > 4 (OR, 10.66; P = < 0.001), and MEWS > 4 (OR, 4.86; P = 0.028). These factors remained predictive of cardiac arrest at the ED. Conclusion: The factors related to cardiac arrest in the ED are ESI 1 patients, ESI 2 patients, patients diagnosed with cardiovascular disease, SpO2 < 94, lactate > 4, and a MEWS > 4. These factors can be used as markers in the event of simultaneous arrival of many patients and can help as a pre-state for patients who have a tendency to develop cardiac arrest. The hemodynamic status and vital signs of these patients should be closely monitored. Early detection of potentially critical conditions to prevent critical medical intervention is mandatory.

Keywords: cardiac arrest, predicting factor, emergency department, emergency patient

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6180 The Implantable MEMS Blood Pressure Sensor Model With Wireless Powering And Data Transmission

Authors: Vitaliy Petrov, Natalia Shusharina, Vitaliy Kasymov, Maksim Patrushev, Evgeny Bogdanov

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The leading worldwide death reasons are ischemic heart disease and other cardiovascular illnesses. Generally, the common symptom is high blood pressure. Long-time blood pressure control is very important for the prophylaxis, correct diagnosis and timely therapy. Non-invasive methods which are based on Korotkoff sounds are impossible to apply often and for a long time. Implantable devices can combine longtime monitoring with high accuracy of measurements. The main purpose of this work is to create a real-time monitoring system for decreasing the death rate from cardiovascular diseases. These days implantable electronic devices began to play an important role in medicine. Usually implantable devices consist of a transmitter, powering which could be wireless with a special made battery and measurement circuit. Common problems in making implantable devices are short lifetime of the battery, big size and biocompatibility. In these work, blood pressure measure will be the focus because it’s one of the main symptoms of cardiovascular diseases. Our device will consist of three parts: the implantable pressure sensor, external transmitter and automated workstation in a hospital. The Implantable part of pressure sensors could be based on piezoresistive or capacitive technologies. Both sensors have some advantages and some limitations. The Developed circuit is based on a small capacitive sensor which is made of the technology of microelectromechanical systems (MEMS). The Capacitive sensor can provide high sensitivity, low power consumption and minimum hysteresis compared to the piezoresistive sensor. For this device, it was selected the oscillator-based circuit where frequency depends from the capacitance of sensor hence from capacitance one can calculate pressure. The external device (transmitter) used for wireless charging and signal transmission. Some implant devices for these applications are passive, the external device sends radio wave signal on internal LC circuit device. The external device gets reflected the signal from the implant and from a change of frequency is possible to calculate changing of capacitance and then blood pressure. However, this method has some disadvantages, such as the patient position dependence and static using. Developed implantable device doesn’t have these disadvantages and sends blood pressure data to the external part in real-time. The external device continuously sends information about blood pressure to hospital cloud service for analysis by a physician. Doctor’s automated workstation at the hospital also acts as a dashboard, which displays actual medical data of patients (which require attention) and stores it in cloud service. Usually, critical heart conditions occur few hours before heart attack but the device is able to send an alarm signal to the hospital for an early action of medical service. The system was tested with wireless charging and data transmission. These results can be used for ASIC design for MEMS pressure sensor.

Keywords: MEMS sensor, RF power, wireless data, oscillator-based circuit

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6179 Inflammatory Markers in the Blood and Chronic Periodontitis

Authors: Saimir Heta, Ilma Robo, Nevila Alliu, Tea Meta

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Background: Plasma levels of inflammatory markers are the expression of the infectious wastes of existing periodontitis, as well as of existing inflammation everywhere in the body. Materials and Methods: The study consists of the clinical part of the measurement of inflammatory markers of 23 patients diagnosed with chronic periodontitis and the recording of parental periodontal parameters of patient periodontal status: hemorrhage index and probe values, before and 7-10 days after non-surgical periodontal treatment. Results: The level of fibrinogen drops according to the categorization of disease progression, active and passive, with the biggest % (18%-30%) at the fluctuation 10-20 mg/d. Fluctuations in fibrinogen level according to the age of patients in the range 0-10 mg/dL under 40 years and over 40 years was 13%-26%, in the range 10-20 mg/dL was 26%-22%, in the 20-40 mg/dL was 9%-4%. Conclusions: Non-surgical periodontal treatment significantly reduces the level of non-inflammatory markers in the blood. Oral health significantly reduces the potential source for periodontal bacteria, with the potential of promoting thromboembolism, through interaction between thrombocytes.

Keywords: chronic periodontitis, atherosclerosis, risk factor, inflammatory markers

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6178 Effect of Substrate Concentration and Pulp Density on Bioleaching of Metals from as Received Spent Refinery Catalyst

Authors: Haragobinda Srichandan, Ashish Pathak, Dong Jin Kim, Seoung-Won Lee

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The present investigation deals with bioleaching of spent refinery catalyst (as received) using At. thiooxidans. The effect of substrate concentration and pulp density was studied. XPS analysis concluded that the metals in spent catalyst were present as both sulfide and oxides. The dissolution behavior of metals during bioleaching was different. During bioleaching, higher dissolution of Ni and lower dissolution of Mo, V and Al was observed. An increase in pulp density from 1% to 10% led to a decrease in leaching yields of all the metals. This was due to the substantial increase in medium pH at higher pulp densities. The maximum negative impact of pulp density was observed on the leaching yield of V. An increase in sulfur concentration from 0.5% to 2.5% didn’t bring positive impact on metal leaching yield. 0.5% sulfur was found to be the optimum above which no significant increase in leaching yields of metals was observed.

Keywords: At. thiooxidans, pulp density, spent catalyst, bioleaching

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6177 Blood Flow Simulations to Understand the Role of the Distal Vascular Branches of Carotid Artery in the Stroke Prediction

Authors: Muhsin Kizhisseri, Jorg Schluter, Saleh Gharie

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Atherosclerosis is the main reason of stroke, which is one of the deadliest diseases in the world. The carotid artery in the brain is the prominent location for atherosclerotic progression, which hinders the blood flow into the brain. The inclusion of computational fluid dynamics (CFD) into the diagnosis cycle to understand the hemodynamics of the patient-specific carotid artery can give insights into stroke prediction. Realistic outlet boundary conditions are an inevitable part of the numerical simulations, which is one of the major factors in determining the accuracy of the CFD results. The Windkessel model-based outlet boundary conditions can give more realistic characteristics of the distal vascular branches of the carotid artery, such as the resistance to the blood flow and compliance of the distal arterial walls. This study aims to find the most influential distal branches of the carotid artery by using the Windkessel model parameters in the outlet boundary conditions. The parametric study approach to Windkessel model parameters can include the geometrical features of the distal branches, such as radius and length. The incorporation of the variations of the geometrical features of the major distal branches such as the middle cerebral artery, anterior cerebral artery, and ophthalmic artery through the Windkessel model can aid in identifying the most influential distal branch in the carotid artery. The results from this study can help physicians and stroke neurologists to have a more detailed and accurate judgment of the patient's condition.

Keywords: stroke, carotid artery, computational fluid dynamics, patient-specific, Windkessel model, distal vascular branches

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6176 Increase of Sensitivity in 3D Suspended Polymeric Microfluidic Platform through Lateral Misalignment

Authors: Ehsan Yazdanpanah Moghadam, Muthukumaran Packirisamy

Abstract:

In the present study, a design of the suspended polymeric microfluidic platform is introduced that is fabricated with three polymeric layers. Changing the microchannel plane to be perpendicular to microcantilever plane, drastically decreases moment of inertia in that direction. In addition, the platform is made of polymer (around five orders of magnitude less compared to silicon). It causes significant increase in the sensitivity of the cantilever deflection. Next, although the dimensions of this platform are constant, by misaligning the embedded microchannels laterally in the suspended microfluidic platform, the sensitivity can be highly increased. The investigation is studied on four fluids including water, seawater, milk, and blood for flow ranges from low rate of 5 to 70 µl/min to obtain the best design with the highest sensitivity. The best design in this study shows the sensitivity increases around 50% for water, seawater, milk, and blood at the flow rate of 70 µl/min by just misaligning the embedded microchannels in the suspended polymeric microfluidic platform.

Keywords: microfluidic, MEMS, biosensor, microresonator

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6175 The Usage of Nitrogen Gas and Alum for Sludge Dewatering

Authors: Mamdouh Yousef Saleh, Medhat Hosny El-Zahar, Shymaa El-Dosoky

Abstract:

In most cases, the associated processing cost of dewatering sludge increase with the solid particles concentration. All experiments in this study were conducted on biological sludge type. All experiments help to reduce the greenhouse gases in addition, the technology used was faster in time and less in cost compared to other methods. First, the bubbling pressure was used to dissolve N₂ gas into the sludge, second alum was added to accelerate the process of coagulation of the sludge particles and facilitate their flotation, and third nitrogen gas was used to help floating the sludge particles and reduce the processing time because of the nitrogen gas from the inert gases. The conclusions of this experiment were as follows: first, the best conditions were obtained when the bubbling pressure was 0.6 bar. Second, the best alum dose was determined to help the sludge agglomerate and float. During the experiment, the best alum dose was 80 mg/L. It increased concentration of the sludge by 7-8 times. Third, the economic dose of nitrogen gas was 60 mg/L with separation efficiency of 85%. The sludge concentration was about 8-9 times. That happened due to the gas released tiny bubbles which adhere to the suspended matter causing them to float to the surface of the water where it could be then removed.

Keywords: nitrogen gas, biological treatment, alum, dewatering sludge, greenhouse gases

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6174 Constraints on Source Rock Organic Matter Biodegradation in the Biogenic Gas Fields in the Sanhu Depression, Qaidam Basin, Northwestern China: A Study of Compound Concentration and Concentration Ratio Changes Using GC-MS Data

Authors: Mengsha Yin

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Extractable organic matter (EOM) from thirty-six biogenic gas source rocks from the Sanhu Depression in Qaidam Basin in northwestern China were obtained via Soxhlet extraction. Twenty-nine of them were conducted SARA (Saturates, Aromatics, Resins and Asphaltenes) separation for bulk composition analysis. Saturated and aromatic fractions of all the extractions were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) to investigate the compound compositions. More abundant n-alkanes, naphthalene, phenanthrene, dibenzothiophene and their alkylated products occur in samples in shallower depths. From 2000m downward, concentrations of these compounds increase sharply, and concentration ratios of more-over-less biodegradation susceptible compounds coincidently decrease dramatically. ∑iC15-16, 18-20/∑nC15-16, 18-20 and hopanoids/∑n-alkanes concentration ratios and mono- and tri-aromatic sterane concentrations and concentration ratios frequently fluctuate with depth rather than trend with it, reflecting effects from organic input and paleoenvironments other than biodegradation. Saturated and aromatic compound distributions on the saturates and aromatics total ion chromatogram (TIC) traces of samples display different degrees of biodegradation. Dramatic and simultaneous variations in compound concentrations and their ratios at 2000m and their changes with depth underneath cooperatively justified the crucial control of burial depth on organic matter biodegradation scales in source rocks and prompted the proposition that 2000m is the bottom depth boundary for active microbial activities in this study. The study helps to better curb the conditions where effective source rocks occur in terms of depth in the Sanhu biogenic gas fields and calls for additional attention to source rock pore size estimation during biogenic gas source rock appraisals.

Keywords: pore space, Sanhu depression, saturated and aromatic hydrocarbon compound concentration, source rock organic matter biodegradation, total ion chromatogram

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6173 Identifying the Mindset of Deaf Benildean Students in Learning Anatomy and Physiology

Authors: Joanne Rieta Miranda

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Learning anatomy and physiology among Deaf Non-Science major students is a challenge. They have this mindset that Anatomy and Physiology are difficult and very technical. In this study, nine (9) deaf students who are business majors were considered. Non-conventional teaching strategies and classroom activities were employed such as cooperative learning, virtual lab, Facebook live, big sky, blood typing, mind mapping, reflections, etc. Of all the activities; the deaf students ranked cooperative learning as the best learning activity. This is where they played doctors. They measured the pulse rate, heart rate and blood pressure of their partner classmate. In terms of mindset, 2 out of 9 students have a growth mindset with some fixed ideas while 7 have a fixed mindset with some growth ideas. All the students passed the course. Three out of nine students got a grade of 90% and above. The teacher was evaluated by the deaf students as very satisfactory with a mean score of 3.54. This means that the learner-centered practices in the classroom are manifested to a great extent.

Keywords: deaf students, learning anatomy and physiology, teaching strategies, learner-entered practices

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6172 Sublethal Effects of Thiamethoxam-Lambda Cyhalothrin on the Life Table Parameters and Population Projection of Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) and Its Parasitoid, Encarsia formosa (Hymenoptera: Aphelinidae)

Authors: Sevda Ddras, Fariba Mehrkhou, Remzi Atlihan, Maryam Fourouzan

Abstract:

The greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), is one of the most important pest on vegetables and ornamental host plants. In this research, the sub-lethal concentration (LC30) of thiamethoxam-lambda cyhalothrin (TLC) on the biological properties, life table parameters and population projection of T. vaporarium and its parasitoid, Encarsia formosa Gahan, were studied at controlled condition (25 ±5 ℃, R.H. 60 ±10 % and a photoperiod of 16:8 h (L:D). Bioassays were conducted by dipping tomato leaves containing third instar nymphs of the whitefly T. vaporariorum, in the obtained LC30 concentration of eforia. The life table data were analyzed using the computer program TWOSEX–MSChart based on the age-stage, two-sex life table theory. The results showed that, usage of sublethal concentration of TLC effected the biological properties and population growth parameters of greenhouse whitefly by shortening the developmentl time, adult longevity, decreasing the fecundity and population growth paramters. Also, the LC30 concentration of TLC had negative effects on life history and life table parameters of E.formosa. The obtained results illustrated that the sublethal concentration of TLC resulted in prolonging of developmental time, decreasing of adult longevity, survival rate and population growth parameters of E.formosa. Additionally, the population projection results were accordance with the population growth rate of either greenhouse whitefly or E.formosa. We conclude that, TLC should not be used in integrated pest management programs where E. formosa exists.

Keywords: greenhouse whitefly, Encarsia formosa, thiamethoxam-lambda cyhalothrin, population projection, life table parameters

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6171 Glycemic Control on Self-Efficacy and Self-Care Behaviors among Omani Adults with Type 2 Diabetes

Authors: Melba Sheila D'Souza, Anandhi Amirtharaj, Shreedevi Balachandran

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Background: Type 2 diabetes has a significant impact on individuals’ health and well-being. Glycemic control may influence self-efficacy and self-care behaviors, and reduce the risk of complications among adults with type 2 diabetes. Type 2 diabetes has substantial morbidity and mortality and 60% of adults’ poor self-care. Glycemic control is associated with reported self-efficacy and self-care behavior. Adults with type 2 diabetes with less information were less likely to take diabetes self-care. Aim: To examine the relationship between glycemic control, demographic factors, clinical factors on self-efficacy, self-care behaviors among Omani adults with type 2 diabetes. Methods: A correlational, descriptive study was used. Omani adults with type 2 diabetes (n=140) were recruited from a public hospital in Oman. The data were collected during January-March 2015. Ethical approval was given by the college research and ethics committee, College of Nursing, and the Hospital, Sultan Qaboos University Data was collected on self-efficacy, self-care behaviors and glycemic control. The study was approved by the Institution Ethics and Research Committee. Bivariate and multivariate analyses were conducted. Results: Most adults had a fasting blood glucose >7.2mmol/L (90.7%), with the majority demonstrating ‘uncontrolled or poor HbA1c of > 8%’ (65%). Variance of self-care behavior (20.6%) and 31.3% of the variance of the self-efficacy was explained by the age, duration of diabetes, medication, HbA1c and prevention of activities of living. Adults with type 2 diabetes with poor glycemic control were more likely to have poor self-efficacy and poor self-care behaviors. Conclusion: This study confirms that self-efficacy model on outcome predicts self-efficacy and self-care behavior. Higher understanding of diabetes, prevention of normal daily activities, higher ability to fit diabetes life in a positive manner and high patient-physician communication were significant with self-efficacy and self-care behaviors. Hence, glycemic control has a high effect on improving self-care behaviors like diet, exercise, medication, foot care and self-efficacy among type 2 diabetes. Implications: Using these findings to improve self-efficacy, individualized self-care management is recommended for better self-efficacy and self-care behaviors among adults with type 2 diabetes.

Keywords: self-efficacy, self-care behaviors, self-care management, glycemic control, type 2 diabetes, nurse

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6170 Comprehending the Relationship between the Red Blood Cells of a Protein 4.1 -/- Patient and Those of Healthy Controls: A Comprehensive Analysis of Tandem Mass Spectrometry Data

Authors: Ahmed M. Hjazi, Bader M. Hjazi

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Protein 4.1 is a crucial component of complex interactions between the cytoskeleton and other junctional complex proteins. When the gene encoding this protein is altered, resulting in reduced expression, or when the protein is absent, the red cell undergoes a significant structural change. This research aims to achieve a deeper comprehension of the biochemical effects of red cell protein deficiency. A Tandem Mass Spectrometry Analysis (TMT-MS/MS) of patient cells lacking protein 4.1 compared to three healthy controls was achieved by the Proteomics Institute of the University of Bristol. The SDS-PAGE and Western blotting were utilized on the original patient sample and controls to partially confirm TMT MS/MS data analysis of the protein-4.1-deficient cells. Compared to healthy controls, protein levels in samples lacking protein 4.1 had a significantly higher concentration of proteins that probably originated from reticulocytes. This could occur if the patient has an elevated reticulocyte count. The increase in chaperone and reticulocyte-associated proteins was most notable in this study. This may result from elevated quantities of reticulocytes in patients with hereditary elliptocytosis.

Keywords: hereditary elliptocytosis, protein 4.1, red cells, tandem mass spectrometry data.

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6169 Analysis of Brain Activities due to Differences in Running Shoe Properties

Authors: Kei Okubo, Yosuke Kurihara, Takashi Kaburagi, Kajiro Watanabe

Abstract:

Many of the ever-growing elderly population require exercise, such as running, for health management. One important element of a runner’s training is the choice of shoes for exercise; shoes are important because they provide the interface between the feet and road. When we purchase shoes, we may instinctively choose a pair after trying on many different pairs of shoes. Selecting the shoes instinctively may work, but it does not guarantee a suitable fit for running activities. Therefore, if we could select suitable shoes for each runner from the viewpoint of brain activities, it would be helpful for validating shoe selection. In this paper, we describe how brain activities show different characteristics during particular task, corresponding to different properties of shoes. Using five subjects, we performed a verification experiment, applying weight, softness, and flexibility as shoe properties. In order to affect the shoe property’s differences to the brain, subjects run for ten min. Before and after running, subjects conducted a paced auditory serial addition task (PASAT) as the particular task; and the subjects’ brain activities during the PASAT are evaluated based on oxyhemoglobin and deoxyhemoglobin relative concentration changes, measured by near-infrared spectroscopy (NIRS). When the brain works actively, oxihemoglobin and deoxyhemoglobin concentration drastically changes; therefore, we calculate the maximum values of concentration changes. In order to normalize relative concentration changes after running, the maximum value are divided by before running maximum value as evaluation parameters. The classification of the groups of shoes is expressed on a self-organizing map (SOM). As a result, deoxyhemoglobin can make clusters for two of the three types of shoes.

Keywords: brain activities, NIRS, PASAT, running shoes

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6168 Plackett-Burman Design for Microencapsulation of Blueberry Bioactive Compounds

Authors: Feyza Tatar, Alime Cengiz, Dilara Sandikçi, Muhammed Dervisoglu, Talip Kahyaoglu

Abstract:

Blueberries are known for their bioactive properties such as high anthocyanin contents, antioxidant activities and potential health benefits. However, anthocyanins are sensitive to environmental conditions during processes. The objective of this study was to evaluate the effects of spray drying conditions on the blueberry microcapsules by Plackett-Burman experimental design. Inlet air temperature (120 and 180°C), feed pump rate (20% and 40%), DE of maltodextrin (6 and 15 DE), coating concentration (10% and 30%) and source of blueberry (Duke and Darrow) were independent variables, tested at high (+1) and low (-1) levels. Encapsulation efficiency (based on total phenol) of blueberry microcapsules was the dependent variable. In addition, anthocyanin content, antioxidant activity, water solubility, water activity and bulk density were measured for blueberry powders. The antioxidant activity of blueberry powders ranged from 72 to 265 mmol Trolox/g and anthocyanin content was changed from 528 to 5500 mg GAE/100g. Encapsulation efficiency was significantly affected (p<0.05) by inlet air temperature and coating concentration. Encapsulation efficiency increased with increasing inlet air temperature and decreasing coating concentration. The highest encapsulation efficiency could be produced by spray drying at 180°C inlet air temperature, 40% pump rate, 6 DE of maltodextrin, 13% maltodextrin concentration and source of duke blueberry.

Keywords: blueberry, microencapsulation, Plackett-Burman design, spray drying

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6167 Post-Exercise Recovery Tracking Based on Electrocardiography-Derived Features

Authors: Pavel Bulai, Taras Pitlik, Tatsiana Kulahava, Timofei Lipski

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The method of Electrocardiography (ECG) interpretation for post-exercise recovery tracking was developed. Metabolic indices (aerobic and anaerobic) were designed using ECG-derived features. This study reports the associations between aerobic and anaerobic indices and classical parameters of the person’s physiological state, including blood biochemistry, glycogen concentration and VO2max changes. During the study 9 participants, healthy, physically active medium trained men and women, which trained 2-4 times per week for at least 9 weeks, fulfilled (i) ECG monitoring using Apple Watch Series 4 (AWS4); (ii) blood biochemical analysis; (iii) maximal oxygen consumption (VO2max) test, (iv) bioimpedance analysis (BIA). ECG signals from a single-lead wrist-wearable device were processed with detection of QRS-complex. Aerobic index (AI) was derived as the normalized slope of QR segment. Anaerobic index (ANI) was derived as the normalized slope of SJ segment. Biochemical parameters, glycogen content and VO2max were evaluated eight times within 3-60 hours after training. ECGs were recorded 5 times per day, plus before and after training, cycloergometry and BIA. The negative correlation between AI and blood markers of the muscles functional status including creatine phosphokinase (r=-0.238, p < 0.008), aspartate aminotransferase (r=-0.249, p < 0.004) and uric acid (r = -0.293, p<0.004) were observed. ANI was also correlated with creatine phosphokinase (r= -0.265, p < 0.003), aspartate aminotransferase (r = -0.292, p < 0.001), lactate dehydrogenase (LDH) (r = -0.190, p < 0.050). So, when the level of muscular enzymes increases during post-exercise fatigue, AI and ANI decrease. During recovery, the level of metabolites is restored, and metabolic indices rising is registered. It can be concluded that AI and ANI adequately reflect the physiology of the muscles during recovery. One of the markers of an athlete’s physiological state is the ratio between testosterone and cortisol (TCR). TCR provides a relative indication of anabolic-catabolic balance and is considered to be more sensitive to training stress than measuring testosterone and cortisol separately. AI shows a strong negative correlation with TCR (r=-0.437, p < 0.001) and correctly represents post-exercise physiology. In order to reveal the relation between the ECG-derived metabolic indices and the state of the cardiorespiratory system, direct measurements of VO2max were carried out at various time points after training sessions. The negative correlation between AI and VO2max (r = -0.342, p < 0.001) was obtained. These data testifying VO2max rising during fatigue are controversial. However, some studies have revealed increased stroke volume after training, that agrees with findings. It is important to note that post-exercise increase in VO2max does not mean an athlete’s readiness for the next training session, because the recovery of the cardiovascular system occurs over a substantially longer period. Negative correlations registered for ANI with glycogen (r = -0.303, p < 0.001), albumin (r = -0.205, p < 0.021) and creatinine (r = -0.268, p < 0.002) reflect the dehydration status of participants after training. Correlations between designed metabolic indices and physiological parameters revealed in this study can be considered as the sufficient evidence to use these indices for assessing the state of person’s aerobic and anaerobic metabolic systems after training during fatigue, recovery and supercompensation.

Keywords: aerobic index, anaerobic index, electrocardiography, supercompensation

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6166 Optimization of the Enzymatic Synthesis of the Silver Core-Shell Nanoparticles

Authors: Lela Pintarić, Iva Rezić, Ana Vrsalović Presečki

Abstract:

Considering an enormous increase of the use of metal nanoparticles with the exactly defined characteristics, the main goal of this research was to found the optimal and environmental friendly method of their synthesis. The synthesis of the inorganic core-shell nanoparticles was optimized as a model. The core-shell nanoparticles are composed of the enzyme core belted with the metal ions, oxides or salts as a shell. In this research, enzyme urease was the core catalyst and the shell nanoparticle was made of silver. Silver nanoparticles are widespread utilized and some of their common uses are: as an addition to disinfectants to ensure an aseptic environment for the patients, as a surface coating for neurosurgical shunts and venous catheters, as an addition to implants, in production of socks for diabetics and athletic clothing where they improve antibacterial characteristics, etc. Characteristics of synthesized nanoparticles directly depend on of their size, so the special care during this optimization was given to the determination of the size of the synthesized nanoparticles. For the purpose of the above mentioned optimization, sixteen experiments were generated by the Design of Experiments (DoE) method and conducted under various temperatures, with different initial concentration of the silver nitrate and constant concentration of the urease of two separate manufacturers. Synthesized nanoparticles were analyzed by the Nanoparticle Tracking Analysis (NTA) method on Malvern NanoSight NS300. Results showed that the initial concentration of the silver ions does not affect the concentration of the synthesized silver nanoparticles neither their size distribution. On the other hand, temperature of the experiments has affected both of the mentioned values.

Keywords: core-shell nanoparticles, optimization, silver, urease

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6165 Polyurethane Membrane Mechanical Property Study for a Novel Carotid Covered Stent

Authors: Keping Zuo, Jia Yin Chia, Gideon Praveen Kumar Vijayakumar, Foad Kabinejadian, Fangsen Cui, Pei Ho, Hwa Liang Leo

Abstract:

Carotid artery is the major vessel supplying blood to the brain. Carotid artery stenosis is one of the three major causes of stroke and the stroke is the fourth leading cause of death and the first leading cause of disability in most developed countries. Although there is an increasing interest in carotid artery stenting for treatment of cervical carotid artery bifurcation therosclerotic disease, currently available bare metal stents cannot provide an adequate protection against the detachment of the plaque fragments over diseased carotid artery, which could result in the formation of micro-emboli and subsequent stroke. Our research group has recently developed a novel preferential covered-stent for carotid artery aims to prevent friable fragments of atherosclerotic plaques from flowing into the cerebral circulation, and yet retaining the ability to preserve the flow of the external carotid artery. The preliminary animal studies have demonstrated the potential of this novel covered-stent design for the treatment of carotid therosclerotic stenosis. The purpose of this study is to evaluate the biomechanical property of PU membrane of different concentration configurations in order to refine the stent coating technique and enhance the clinical performance of our novel carotid covered stent. Results from this study also provide necessary material property information crucial for accurate simulation analysis for our stents. Method: Medical grade Polyurethane (ChronoFlex AR) was used to prepare PU membrane specimens. Different PU membrane configurations were subjected to uniaxial test: 22%, 16%, and 11% PU solution were made by mixing the original solution with proper amount of the Dimethylacetamide (DMAC). The specimens were then immersed in physiological saline solution for 24 hours before test. All specimens were moistened with saline solution before mounting and subsequent uniaxial testing. The specimens were preconditioned by loading the PU membrane sample to a peak stress of 5.5 Mpa for 10 consecutive cycles at a rate of 50 mm/min. The specimens were then stretched to failure at the same loading rate. Result: The results showed that the stress-strain response curves of all PU membrane samples exhibited nonlinear characteristic. For the ultimate failure stress, 22% PU membrane was significantly higher than 16% (p<0.05). In general, our preliminary results showed that lower concentration PU membrane is stiffer than the higher concentration one. From the perspective of mechanical properties, 22% PU membrane is a better choice for the covered stent. Interestingly, the hyperelastic Ogden model is able to accurately capture the nonlinear, isotropic stress-strain behavior of PU membrane with R2 of 0.9977 ± 0.00172. This result will be useful for future biomechanical analysis of our stent designs and will play an important role for computational modeling of our covered stent fatigue study.

Keywords: carotid artery, covered stent, nonlinear, hyperelastic, stress, strain

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