142 research outputs found
Effect of hormonal and copper IUDs on genital microbial colonisation and clinical outcomes in North-Western Nigeria
Background: Intrauterine devices are one of the popular long term reversible contraceptive methods. Earlier forms were associated with genital infections, however more recent types such copper IUDs and hormonal types have been shown to have better safety profile. However, there is no conclusive evidence to demonstrate that hormonal IUD is less associated with genital infection when compared with copper IUDs. The objectives include determination of prevalence of genital tract infections among IUD users, to determine the type of IUD that is less associated with genital infection, and also determine clinical features seen among IUD users.Methods: We conducted a descriptive, cross sectional study of clients who were at 6 months following IUD insertion. Endocervical and high vaginal samples were taken to isolate microbes.Results: The prevalence of genital tract infection was 20% in Copper IUD users and 8.6% among LNG-IUS users. Genital infection was significantly higher among copper IUD users compared to hormonal IUD users (p=0.038, OR= 2.88). Abnormal vaginal discharge was the commonest symptoms among IUD users and formal education was associated with less risk of genital infections (p=0.048).Conclusions: Hormonal IUDs are less associated with genital tract infection compared to copper IUDs and women with formal education are less likely to have genital infection among IUD users
Analysis of the Impact of Relative Humidity and Mineral Nuclei Mode Aerosols Particle Concentration on the Visibility of Desert Aerosols
This paper presents the results of the Analysis of the Impact of relative humidity and water-soluble aerosol particle concentrations on the visibility and particle size distribution of desert aerosols based on microphysical properties of desert aerosols. The microphysical properties (the extinction coefficients, volume mix ratios, dry mode radii and wet mode radii) were extracted from Optical Properties of Aerosols and Clouds (OPAC 4.0) at eight relative humidities (00 to 99%RH) and at the spectral range of 0.4-0.8 mm. the concentrations of mineral nuclie component (MINN) were varied to obtain five different models. The angstrom exponent (a), the turbidity (b), the curvature (a2), humidification factor (g), the mean exponent of aerosol growth curve (µ) and the mean exponent of aerosol size distributions (n) were determined from the regression analysis of some standard equations. It was observed that the values of (a) are less than 1 throughout the 5 models which signifies the dominance of coarse mode particles over fine mode particles. It was observed that the curvature (a2) has both monomodal and bimodal types of distributions all through the 5 models and this signifies the dominance of coarse mode particles with some traces of fine mode particles. The visibility was observed to decrease with the increase in RH and increased with wavelength. The analysis further found that there is an inverse power law relationship between humidification factor, the mean exponent of the aerosol size distribution with the mean exponent of the aerosol growth curve (as the magnitude of (µ) decreases across the five models, the magnitudes of (g) and (n) increase, but the magnitude of both (g) and (n) increases for a given (µ) across the individual models). The mean exponent of aerosol size distribution (µ) being less than 3 indicate hazy condition of the desert atmosphere
Design and validation of a wide area monitoring and control system for fast frequency response
This paper presents the design and validation of a Wide Area Monitoring and Control (WAMC) system for Fast Frequency Response (FFR) to address the challenges associated with reduced and non-uniformly distributed inertia in power systems. The WAMC system, designed for the power system in Great Britain, is termed "Enhanced Frequency Control Capability (EFCC)". It uses real time measurements from Phasor Measurement Units (PMUs) to monitor the system state in order to rapidly detect frequency disturbances and evaluate the magnitude of power imbalances. The impact of the disturbances on different parts of the network is considered to subsequently allocate the required response for different regions of the network, all within less than one second from the initiating event. The capabilities and characteristics of different resources (e.g. wind, energy storage, demand, etc.) are also evaluated and taken into account to achieve a suitable, optimized and coordinated response. Case studies using highly realistic hardware-in-the-loop setups are presented and these demonstrate that the proposed system is capable of detecting frequency events and deploying appropriate and coordinated responses in a timely fashion even with degraded communication conditions, thereby effectively enhancing the frequency control in future low-inertia systems and permitting higher penetrations of low-carbon and low-inertia energy sources
Shielding properties of the cellular structures with carbon-containing materials and foiled foam polyethylene
Предложен способ создания экранов электромагнитного излучения с применением
нетканого иглопробивного полотна, содержащего углеродные добавки, и вспененного полиэтилена,
покрытого алюминиевой фольгой. Для повышения коэффициентов отражения и поглощения
предлагается создание ячеистой структуры, содержащей фрагменты обоих видов материалов с длиной
от 20 до 40 мм и шириной от 5 до 8 мм. Измерение экранирующих характеристик проводилось
на автоматизированном измерителе модуля коэффициентов передачи и отражения SNA 0.01–18
в диапазоне частот 0,7…17,0 ГГц. Показано, что значения коэффициентов отражения в диапазоне частот
составили –0,5…–4,5 дБ при значениях коэффициента передачи ЭМИ –4,0…–25,0 дБ.
The method to produce electromagnetic radiation shields using a non-woven needle-punched fabric
containing carbon additives and foamed polyethylene coated with aluminum foil is proposed. To increase
the reflection and absorption coefficients, it is proposed to create a cellular structure containing fragments of both types of materials with length from 20 to 40 mm and width from 5 to 8 mm. The measurement of the
shielding characteristics was carried out on the automated meter of the transmission and reflection coefficient
SNA 0.01–18 in the frequency range 0.7…17.0 GHz. It is shown that the values of the reflection coefficients
in the frequency range 0.7…17.0 GHz were –0.5…–4.5 dB and the values of the transmission coefficient
of electromagnetic radiation were –4.0…–25.0 dB
A High-Throughput Comet Assay Approach for Assessing Cellular DNA Damage
open access articleCells are continually exposed to agents arising from the internal and external environments, which may damage DNA. This damage can cause aberrant cell function, and therefore DNA damage may play a critical role in the development of, conceivably, all major human diseases, e.g., cancer, neurodegenerative and cardiovascular disease, and aging. Single-cell gel electrophoresis (i.e., the comet assay) is one of the most common and sensitive methods to study the formation and repair of a wide range of types of DNA damage (e.g., single- and double-strand breaks, alkali-labile sites, DNA-DNA crosslinks, and, in combination with
certain repair enzymes, oxidized purines, and pyrimidines), in both in vitro and in vivo systems. However, the low sample throughput of the conventional assay and laborious sample workup are limiting factors to its widest possible application. With the
"scoring" of comets increasingly automated, the limitation is now the ability to process significant numbers of comet slides. Here, a high-throughput (HTP) variant of the comet assay (HTP comet assay) has been developed, which significantly increases
the number of samples analyzed, decreases assay run time, the number of individual slide manipulations, reagent requirements, and risk of physical damage to the gels. Furthermore, the footprint of the electrophoresis tank is significantly decreased due
to the vertical orientation of the slides and integral cooling. Also reported here is a novel approach to chilling comet assay slides, which conveniently and efficiently facilitates the solidification of the comet gels. Here, the application of these devices to
representative comet assay methods has been described. These simple innovations greatly support the use of the comet assay and its application to areas of study such as exposure biology, ecotoxicology, biomonitoring, toxicity screening/testing, together
with understanding pathogenesis
Assessment of Coriolis meters as instrumentation for gas void fraction measurement in air–liquid multiphase flow in a pipeline riser system
Measurement of void fraction in gas-liquid flow systems is important in determining pumping requirements, designing downstream facilities and in detecting off-design problems such as cavitation and flashing during operation. Hence, it is key that this parameter is known in real time during oil & gas production and other process operation. As a result, the use of clamp-on flow meters which operate on the Coriolis principle are useful for such purposes as they instantaneously measure the flow’s density which can change depending on the gas fraction in the flowing mixture. In this study, we demonstrate the use of Coriolis mass flow meters in instantaneously measuring the void fraction in a multiphase mixture flowing in a 2-inch pipeline riser system at Cranfield University, UK. A Coriolis meter was installed on the vertical section of the facility. A set of experiments were conducted at fixed liquid superficial velocities of 0.25 and 1 m/s and air flow rates of 6-100 Sm3/h (corresponding to 0.39–3 m/s). The instantaneous densities of the mixtures were recorded at 100 Hz acquisition frequency. These were then used to estimate the gas void fraction at the vertical section using the homogenous model for the mixture density. Also, a well-calibrated 16 by 16 wire mesh sensor (WMS) fitted at the same vertical location to validate the gas void fraction measurements of the Coriolis flow meter. It was found that the Coriolis flow meter presented excellent agreement with the WMS for void fraction measurement at high gas flow rates. We observed that the agreement coincided with conditions that exhibit core-peaking void fraction distributions, i.e., at conditions that are not bubbly flow. Hence, it may be concluded that the Coriolis flow meter can be used with some confidence in industrial application at these condition
Comparative analysis of riser base and flowline gas injection on vertical gas-liquid two-phase flow
Gas injection is a frequently used method for artificial lift and flow regime rectification in offshore production and transportation flowlines. The flow behaviour in such flowlines is complex and a better understanding of flow characteristics, such as flow patterns, void fraction/hold up distributions and pressure gradient is always required for efficient and optimal design of downstream handling facilities. Injection method and location have been shown to strongly affect downstream fluid behaviour that can have important implications for pumping and downstream facility design, especially if the development length between pipeline and downstream facility is less than L/D = 50 as reported by many investigators. In this article, we provide the results of an experimental investigation into the effects of the gas injection position on the characteristics of the downstream upwards vertical gas flow using a vertical riser with an internal diameter of 52 mm and a length of 10.5 m. A horizontal 40-m-long section connected at the bottom provides options for riser base or horizontal flow line injection of gas. The flowline gas injection is performed 40 m upstream of the riser base. A 16 by 16 capacitance wire mesh sensor and a gamma densitometer were used to measure the gas-liquid phase cross-sectional distribution at the riser top. A detailed analysis of the flow characteristics is carried out based on the measurements. These include flow regimes, cross-sectional liquid holdup distributions and peaking patterns as well as analysis of the time series data. Our findings show that flow behaviours differences due to different gas injection locations were persisting after a development length of 180D in the riser. More specifically, core-peaking liquid holdup occurred at the lower gas injection rates through the flowline, while wall-peaking holdup profiles were established at the same flow conditions for riser base injection. Wall peaking was associated with dispersed bubbly flows and hence non-pulsating as against core-peaking was associated with Taylor bubbles and slug flows. Furthermore, it was found that the riser base injection generally produced lower holdups. It was noted that the circumferential injector used at the riser base promoted high void fraction and hence low liquid holdups. Due to the bubbly flow structure, the slip velocity is smaller than for larger cap bubbles and hence the void fraction is higher. The measurements and observations presented in the paper provides valuable knowledge on riser base/flowline gas introduction that can directly feed into the design of downstream facilities such as storage tanks, slug catchers and separators
Optical character recognition on heterogeneous SoC for HD automatic number plate recognition system
Automatic number plate recognition (ANPR) systems are becoming vital for safety and security purposes. Typical ANPR systems are based on three stages: number plate localization (NPL), character segmentation (CS), and optical character recognition (OCR). Recently, high definition (HD) cameras have been used to improve their recognition rates. In this paper, four algorithms are proposed for the OCR stage of a real-time HD ANPR system. The proposed algorithms are based on feature extraction (vector crossing, zoning, combined zoning, and vector crossing) and template matching techniques. All proposed algorithms have been implemented using MATLAB as a proof of concept and the best one has been selected for hardware implementation using a heterogeneous system on chip (SoC) platform. The selected platform is the Xilinx Zynq-7000 All Programmable SoC, which consists of an ARM processor and programmable logic. Obtained hardware implementation results have shown that the proposed system can recognize one character in 0.63 ms, with an accuracy of 99.5% while utilizing around 6% of the programmable logic resources. In addition, the use of the heterogenous SoC consumes 36 W which is equivalent to saving around 80% of the energy consumed by the PC used in this work, whereas it is smaller in size by 95%
Novel De Novo Mutation in Sulfonylurea Receptor 1 Presenting as Hyperinsulinism in Infancy Followed by Overt Diabetes in Early Adolescence
OBJECTIVE—Congenital hyperinsulinism, usually associated with severe neonatal hypoglycemia, may progress to diabetes, typically during the 4th decade of life in nonpancreatectomized patients. We aimed to genotype the ATP-sensitive K+ channel in a 10.5-year-old girl presenting with overt diabetes following hyperinsulinism in infancy
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