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Search Results: 1 - 10 of 363 matches for " Aleksey Shaporev "
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BluetoothTM Enabled Acceleration Tracking (BEAT) mHealth System: Validation and Proof of Concept for Real-Time Monitoring of Physical Activity  [PDF]
Aleksey Shaporev, Mathew Gregoski, Vladimir Reukov, Teresa Kelechi, David Morgan Kwartowitz, Frank Treiber, Alexey Vertegel
E-Health Telecommunication Systems and Networks (ETSN) , 2013, DOI: 10.4236/etsn.2013.23007
Abstract: Physical activity is critical to improve the condition of patients with chronic leg and foot ulcers, especially those who are obese and experienced multiple co-morbid conditions. Unfortunately, these individuals are unable to engage in guideline based physical activity (PA) programs. A prototype of BluetoothTM enabled acceleration tracking (BEAT) mHealth system was developed and manufactured for remote monitoring and stimulation of adherence to PA in deconditioned patients. The system consists of a miniature accelerometer-based sensor, smartphone application, and a network service. Validation testing showed high reliability and reproducibility of the BEAT sensors. Pilot study with human subjects demonstrated high accuracy of the BEAT system in recognition of different exercises and calculating overall outcomes of PA. Taken together, these results indicate that BEAT system could become a valuable tool for realtime monitoring of PA in deconditioned patients.

 

Development and Validation of a Smartphone Heart Rate Acquisition Application for Health Promotion and Wellness Telehealth Applications
Mathew J. Gregoski,Martina Mueller,Alexey Vertegel,Aleksey Shaporev,Brenda B. Jackson,Ronja M. Frenzel,Sara M. Sprehn,Frank A. Treiber
International Journal of Telemedicine and Applications , 2012, DOI: 10.1155/2012/696324
Abstract: Objective. Current generation smartphones' video camera technologies enable photoplethysmographic (PPG) acquisition and heart rate (HR) measurement. The study objective was to develop an Android application and compare HRs derived from a Motorola Droid to electrocardiograph (ECG) and Nonin 9560BT pulse oximeter readings during various movement-free tasks. Materials and Methods. HRs were collected simultaneously from 14 subjects, ages 20 to 58, healthy or with clinical conditions, using the 3 devices during 5-minute periods while at rest, reading aloud under observation, and playing a video game. Correlation between the 3 devices was determined, and Bland-Altman plots for all possible pairs of devices across all conditions assessed agreement. Results. Across conditions, all device pairs showed high correlations. Bland-Altman plots further revealed the Droid as a valid measure for HR acquisition. Across all conditions, the Droid compared to ECG, 95% of the data points (differences between devices) fell within the limits of agreement. Conclusion. The Android application provides valid HRs at varying levels of movement free mental/perceptual motor exertion. Lack of electrode patches or wireless sensor telemetric straps make it advantageous for use in mobile-cell-phone-delivered health promotion and wellness programs. Further validation is needed to determine its applicability while engaging in physical movement-related activities. 1. Introduction Many cellular phones now possess high-speed data transmission capabilities (e.g., 3G, 4G) and have embedded microprocessors (e.g., Bluetooth, ANT) with the capability to wirelessly connect to external devices. As a result, cell phones offer several advantages over desktop or laptop computers in telemonitoring-related applications such as higher population penetration, increased privacy, lower cost to purchase, easier ability to transport, and overall increased personal convenience of use [1, 2]. Cell phones are widely used in telemonitoring serving as a conduit for receiving biohealth information from portable medical devices (e.g., blood pressure, glucose and pulse oximeter monitors, weight scales) and mobile sensors (e.g., physical activity; accelerometer counts, heart rate, respiration rate, pulse pressure via chest- or armbands, and wireless electrodes). Once cell phones have received the pertinent information, it is microprocessed, encrypted, and the data packets are transferred to some form of localized or web-based server for secondary processing. At the server level, the data packets are organized into a
On Lucas Sequences Computation  [PDF]
Aleksey Koval
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.312128
Abstract: This paper introduces an improvement to a currently published algorithm to compute both Lucas "sister" sequences Vk and Uk. The proposed algorithm uses Lucas sequence properties to improve the running time by about 20% over the algorithm published in [1].
First Evidence of Surface SH-Wave Propagation in Cubic Piezomagnetics  [PDF]
Aleksey Zakharenko
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.25037
Abstract: This theoretical work provides with results of characteristics calculation of the ultrasonic surface Zakharenko waves (USZWs) existing in piezomagnetic cubic monocrystals of class m3m that can be readily used for non-destructive testing. The piezomagnetic waves propagate in direction [101] corresponding to relatively easy magnetization for the following piezomagnetics: Galfenol, Terfenol-D, and CoFe2O4 with cubic structures. The phase velocities of the USZW-waves and the coefficient of magnetomechanical coupling (CMMC) K2 were calculated for the crystals. It was found that the coefficient K2 for piezomagnetics with Km2 > 1/3 and Km2 >> 1/3 is about 8% to 9%, where K2 = 2 (VUSZW,o – VUSZW,c)/VUSZW,o and Km2 = h2/(Cμ). Knowledge of piezomagnetic properties of cubic crystals makes possible the use of them in new products utilizing the phenomenon called the magnetoelectric effect. Also, this study is useful for possible application of cubic piezomagnetics in composite structures consisting of piezoelectric and (or) piezomagnetic materials and in the microwave technology. This broadens choice of possible piezomagnetic materials for utilization in various technical devices.
Prevalence and Antibiotic Resistance Pattern of Escherichia coli and Klebsiella pneumoniae in Urine Tract Infections at the La Paz Medical Center, Malabo, Equatorial Guinea  [PDF]
Aleksey Shatalov
Open Journal of Medical Microbiology (OJMM) , 2015, DOI: 10.4236/ojmm.2015.54022
Abstract: The study was conducted to isolate and determine the antibiotic resistance in Escherichia coli and Klebsiella pneumonia from urine samples over a 2-year period (August 2013-September 2015) at the La Paz Medical Center, Malabo. A retrospective analysis of 785 urine culture samples over a 2-year period August 2013-September 2015 was carried out according to the routine protocol of urinalysis. Bacterial etiological agents were isolated from 155 (19.7%) samples with highest prevalence of Escherichia coli (55.5%) followed by Klebsiella pneumonia (23.2%), Proteus mirabilis (4.5%), Pseudomonas species (3.2%), Enterobacter species (2.6%), Enterococcus faecalis (2.6%) and others species (8.4%). The E. coli and K. pneumonia represent 78.7% of all isolated bacterial strains. The E. coli and K. pneumoniae isolates possess highly resistant to ampicillin, Trimethoprim/Sulfamethoxazole, Doxycycline, Amoxicicline/Clavulanic acid. Whereas K. pneumonia demonstrated also to be highly resistant to Gentamycin, Cefuroxime and Ceftriaxon, low level of resistance to Piperacilin/Tazobactam, Amikacin and the lowest to Imipenem. The alarming level of MDR strains to the first choice antibiotics treatment was observed.
Multi-Drug Resistance Pattern of Lactose Non-Fermenting Escherichia coli as Causative Agent of Urine Tract Infections in Luanda, Angola  [PDF]
Aleksey Shatalov
Open Journal of Medical Microbiology (OJMM) , 2019, DOI: 10.4236/ojmm.2019.91001
Abstract: This prospective study was carried out to assess the sensitivity and resistance pattern of lactose non-fermenting Escherichia coli from July 2018 to December 2018 in the Laboratory of Microbiology at Luanda Medical Center, Angola. Out of 1170 patient, a total of 120 urine specimens infected with Escherichia coli (>105 CFU/ml) were collected according to the routine protocol of urinalysis. Among these 120 isolates, 25 (21%) isolates were determined as “atypical”, lactose non-fermenting E. colis trains. The twenty-five lactose non-fermenting Escherichia coli strains isolated from urine samples in Luanda Medical Center were declared as Multiple Drugs-Resistant strains with high resistance to Cefalexine (100%), Cefuroxime (100%), Ceftriaxone (92%), Gentamycin (92%), Ciprofloxacin (72%) and Amoxiciclin/Clavulanic (80%). The alarming resistance level to the first-choice drugs for the treatment of urinary tract infections caused by non-fermentative lactose E. coli was observed.
Stationary Characteristics of the Single-Server Queue System with Losses and Immediate Service Quality Control  [PDF]
Aleksey I. Peschansky
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.24049
Abstract: Semi-Markovian model of operation of a single-server queue system with losses and immediate service quality control has been built. In case of unsatisfactory request service quality, its re-servicing is carried out. Re-servicing is executed till it is regarded satisfactory. Time between request income, and request service time are assumed to be random values with distribution functions of general kind. An explicit form of the system stationary characteristics has been defined.
New Interfacial Shear-Horizontal Waves in Piezoelectric Cubic Crystals  [PDF]
Aleksey Anatolievich Zakharenko
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.211083
Abstract: This theoretical study reports results on acoustic wave propagation along the interface of two half-spaces representing cubic crystals of both piezoelectric classes ?43m and 23 with strong piezoelectric effect. In similar configurations, the interfacial Maerfeld-Tournois waves can propagate along the interface of two transversely-isotropic materials of class 6 mm, in which the shear-horizontal surface acoustic waves (SH-SAWs) called the Bleustein-Gulyaev (BG) waves can also exist. Cubic piezoelectrics cannot support existence of the surface BG-waves, according to the recent report by Gulyaev and Hickernell. Hence, new interfacial SH-waves are studied in this paper concerning unique direction [101] of wave propagation in cubic crystals using different electrical boundary conditions (EBCs) of both metallized and non-metallized interfaces. The new interfacial SH-waves can always propagate along the interface of two identical piezoelectric crystals with opposite polarization. In this case, the calculated velocities for both EBCs coincide with the velocity of the ultrasonic surface Zakharenko wave (USZW) propagating in direction [101] on the metallized surface of a cubic piezoelectrics. It was also found that the new interfacial SH-waves can exist when wave propagation is along the interface of two dissimilar half-spaces, for instance, the piezoelectric cubic crystals Bi12SiO20 and Bi12GeO20. Several calculations are also carried out as examples. PACS: 51.40.+p, 62.65.+k, 68.35.Gy, 68.35.Iv, 68.60.Bs, 74.25.Ld.
Studying Magnetization Distribution in Magnetic Thin Films under Transversal Application of Magnetic Fields  [PDF]
Aleksey Anatolievich Zakharenko
Journal of Modern Physics (JMP) , 2010, DOI: 10.4236/jmp.2010.11004
Abstract: The problem of magnetization change across the direction of magnetic field for a magnetic layer with non-symmetric boundary conditions was treated. The exact solution of the problem for the magnetization components mx and my was written in the form of complex combination of Jacobian elliptic functions and elliptic integrals. This allows one to demonstrate both the static mode and all dynamic modes for the mag-netization distribution across the layer thickness. The static mode and several dynamic modes, as well as the first and second derivatives of the magnetization components, were calculated. Also, average values of the magnetization components ?mx? and ámy? for the static mode and three dynamic modes were calculated in dependence on the magnetic field. The obtained results can represent an interest in the large amount of ap-plications of magnetic devices such as recording media, memory chips, and computer disks. The results are also useful for checking different numerical methods recently applied to study the problem, because it is thought that any numerical method cannot demonstrate solutions for the dynamic modes.
On Propagation Problems of New Surface Wave in Cubic Piezoelectromagnetics  [PDF]
Aleksey Anatolievich Zakharenko
Open Journal of Acoustics (OJA) , 2012, DOI: 10.4236/oja.2012.23012
Abstract: This theoretical paper analytically predicts the existence of new surface wave in propagation direction [101] in the cubic piezoelectromagnetics. The solution for the velocity of the new wave is given in an explicit form. Such new wave possesses one real component and two purely imaginary components. This corresponds to a leaky acoustic SH-wave. However, in this case the real component does not participate in the complete displacements. As a result, the new wave can represent the new shear-horizontal surface acoustic wave (SH-SAW) for suitable boundary conditions. For the me-chanically free surface, several combinations of the following electrical and magnetic boundary conditions were used: electrically closed, electrically open, magnetically closed, magnetically open surface. This new SH-SAW can propagate with the speed slightly larger than that for the SH bulk acoustic wave coupled with both the electrical and magnetic potentials. The existence conditions for the new SH-SAW were also discussed. They can be very complicated and depend on all the material parameters. It was also discussed that the results can be true for the left-handed metamaterials. It is thought that the new SH-SAW can be produced by electromagnetic acoustic transducers (EMATs) because generation of SH-SAWs is feasible with the EMATs. This can be a problem for experimentalists working in the research arenas such as acoustooptics, photonics, and acoustooptoelectronics.
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