Search

This article provides a status report on the global burden of common cancers in male worldwide using the GLOBOCAN 2018 estimates of cancer incidence and mortality. Based on the results of cancer records in 2018, 9,456,418 cases of malignancy were recorded in males, with lung cancer (1,368,524 cases, 14.5%), prostate cancer (1,276,106 cases, 13.5%), colorectal cancer (1,026,215 cases, 10.9% %), stomach cancer (683,754 cases, 7.2%), and liver cancer (596,574 cases, 6.3%) were the five most common cancers in men worldwide. The total number of deaths due to cancer in humans in 2018 is 5,385,640. The five causes of death due to cancer in men worldwide are lung cancer (1,184,947 cases, 22%), liver (548,375 cases, 2.10%), stomach cancer (513,555 cases, 9.5%), colorectal cancer (484,224 cases, 9%), and prostate cancer (358,989 cases, 7.7%). Our results showed that there was a positive correlation between the incidence of lung cancer (R = 0.629, P < 0.0001), prostate cancer (R = 0.534, P < 0.0001), colorectal cancer (R = 0.745, P < 0.0001), and stomach cancer (R = 0.268, P < 0.001) with human development index (HDI) index, while there was no significant relationship between liver cancer and the HDI (R = 0.079, P > 0.05). The results also showed that there was a positive and significant correlation between mortality from lung cancer (R = 0.632, P < 0.0001) and colorectal cancer (R = 0.627, P < 0.0001) with HDI, whereas this correlation was negative for prostate cancer (R = -0.187, P < 0.01). [ABSTRACT FROM AUTHOR]

Resonant switched-capacitor converters (SCCs) are being increasingly used in energy conversion systems due to their low cost, low weight, and high efficiency. The zero-current switching (ZCS) feature of an SCC, which can be achieved at a switching frequency below the resonant frequency, not only results in soft switching and, hence, low switching losses, but also reduces the electromagnetic interference caused by the converter. This paper proposes a cascaded step-down SCC (CSD-SCC) with an arbitrary number of converter stages and an exponential output-to-input voltage ratio. This SCC reduces the number of required converter stages for a low voltage conversion ratio and has a low ripple in the output voltage. A mathematical study is proposed to analyze the operating modes of this generalized CSD-SCC under ZCS operation. This study also enables the calculation of the output voltage, the output voltage ripple, and the efficiency for different switching frequencies and loads. The proposed analysis is validated via several simulation and experimental case studies, including a photovoltaic energy conversion system. The experimental CSD-SCC has two converter stages with an efficiency higher than  $\text{95}\%$. [ABSTRACT FROM AUTHOR]

Massive windings must be used for strong magnetic field applications, which results in low magnetic field uniformity. In this paper, a simple circular Helmholtz coil system is analyzed to identify the main causes of the problems, which arise for high intensity uniform magnetic field applications. Here, dominant deformations of the circular solenoid winding cross-section shape and its dimensions effects on the generated magnetic field and its uniformity are analyzed. These analyses can be applied to the modified Helmholtz coil and multi-axial systems, as well. The system dimensions are optimized and normalized to easily scale the given results for any desired uniform magnetic field and workspace without doing further laborious calculations. The optimized dimensions increase the magnetic field uniformity in a large portion of the available workspace and realize the desired magnetic field at the center of the system. Also, the necessary conductor mass and the total electrical power are reduced. To verify the given analyses, two small-scale Helmholtz coil systems have been implemented and their generated magnetic fields and nonuniformities have been measured under a variety of conditions. [ABSTRACT FROM PUBLISHER]

Resonant switched-capacitor converters have widely been used recently to increase conversion power density. The most significant drawback of these converters is voltage regulation problem when their input voltages vary in wide ranges. Here, a basic double voltage-ratio resonant switched-capacitor converter (SCC) is analyzed and simulated below its resonant frequency under the different operation modes to overcome this problem. The converter different parameters are calculated under both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) conditions. The advantages and drawbacks of these operation modes are compared and the closed-loop control of the converter is also investigated based on the extended describing function approach. The given analyses demonstrate that the output voltage can be well-regulated under the CCM1 and DCM2 operation modes even when wide input voltage and load variations are applied. Besides, the DCM1 operation mode must be avoided when output voltage regulation is important. Based on the given analytical and experimental results, switching frequency varies in a reasonable range to regulate the output voltage. Also, faster transient responses, smaller output capacitor, and smaller resonant tank components can be used below the resonant frequency, as compared to the above resonant frequency, but lower efficiency value is achieved. The given approach has been extended to the other resonant SCCs as well. [ABSTRACT FROM PUBLISHER]

Objective: There is a likelihood of risky behaviors such as drug abuse, risky sexual behavior, and adaptability issues in young ages. The present study aimed at investigating the prevalence of risky behaviors among students of Dezful University of Medical Sciences in 2014. Methods: This was a descriptive-analytical cross sectional study, with a random sampling approach. Scale of measuring risky behaviors was used to measure the risky behaviors (high speed driving, maim, drug use, and sexual behaviors) and related factors. The mean, standard deviation, Chi-square tests, t tests, and ANOVA were used for data analysis. Results: The study was conducted on 150 (50%) female and 150 (50%) male students. Most of the participants aged 20 to 24 years. A statistically significant difference was obtained between the average scores of risky behaviors among female and male students (p<0.05). The results of the present study revealed that the prevalence of risky behaviors, high speed driving, and drug consumption was different among the students of various study fields (p<0.05). Conclusion: The prevalence of risky behaviors among students of Dezful University was relatively low, and the prevalence of these behaviors in female students was far less than in male students. Risky behaviors were associated with background variables, except for mother's occupation. [ABSTRACT FROM AUTHOR]

In single-phase grid-connected photovoltaic inverters, the input power is constant during the grid period, whereas the output power oscillates at double-line frequency. Therefore, electrolytic capacitors are widely used to handle the input and output power differences. However, these capacitors have short lifetime which degrade the inverter reliability. This paper proposes a control strategy to turn a conventional four-switch flyback-based inverter to an inverter equipped with a series power decoupling circuit. Therefore, a long lifetime film capacitor can be used as the main energy storage. The modified inverter has an inherent snubber circuit, which can restore energy of the transformer leakage inductance and improves its overall efficiency. The control strategy can realise maximum power point tracking and inject a sinusoidal low total harmonic distortion current to the grid. A 100 W prototype inverter has been built to verify operation and feasibility of the proposed control strategy. [ABSTRACT FROM AUTHOR]

In this paper, a novel single-stage three-port inverter that connects photovoltaic (PV) panel to a single-phase power grid is introduced. In a single-phase grid-connected PV panel, the input power is constant during the line-frequency period, while the output power oscillates at double-line frequency. A series active power decoupling circuit utilizing thin-film capacitors is incorporated to a conventional flyback inverter to handle input and output power differences. Therefore, popularly low-reliable electrolytic capacitors are replaced with small long-lifetime thin film. The proposed inverter can extract the maximum power from PV, deliver a low total harmonic distortion sinusoidal current to the output, and decouple the input and output powers. The proposed power decoupling circuit shares the inverter main switch. Thus, these functions are achieved using just three switches and a simple control scheme which is applicable for both charging and discharging states. Operation principle and control strategy are discussed in detail. Experimental results based on a 100-W prototype inverter verify feasibility and functionality of the proposed inverter. [ABSTRACT FROM PUBLISHER]

Multiterminal converters eliminate using several single-input-single-output converters and simplify their topologies and reduce their cost. In this paper, a new family of multi-input converters based on three switches leg is introduced. Inputs of the proposed converters are similar and they are topologically interchangeable and have boost or buck operation modes. The proposed converter has one output that operates as an inverter. Here, all operating modes of the proposed converters and their effects on each other are investigated, in details. Also, an appropriate switching technique for the converters is given. A detailed comparison between conventional and proposed two-input converters is also presented. A two-input, one-output prototype converter has been implemented to validate the given analyses and to verify the proposed converter's performance. The experimental results are in good agreement with the theoretical and simulated analyses. [ABSTRACT FROM AUTHOR]

A resonant switched-capacitor converter (SCC) has been analyzed above its resonant frequency to realize zero-voltage switching (ZVS) and to overcome voltage regulation issue of SCCs even when wide input voltage and output power variations are applied. ZVS operation under the continuous conduction mode (CCM) conditions improves efficiency due to lower conduction and switching losses. It is more efficient than the widely used zero-current switching (ZCS) approach in recent years under the discontinuous conduction mode (DCM) condition. Because, switching losses dominant components are reduced in MOSFET-based converters under the ZVS not ZCS conditions. Also, it has been demonstrated that output voltage can be well regulated under the CCM operation when wide input voltage and load variations are used. When output voltage regulation is not the major issue, operating at fixed switching frequency higher than, but near to, the resonant frequency results smaller components, higher power density, and lower electromagnetic interference level, as compared to the constant voltage ratio DCM operation mode, widely used in recent years. Also, output voltage ripple has been calculated, in details, by considering parasitic components of the output capacitor. A 110–165 to 200 V SCC has been implemented in 206.6–402.5 kHz frequency range to deliver 100–500 W. Maximum and average efficiency values equal to 96.8% and 94% are achieved, respectively. [ABSTRACT FROM PUBLISHER]

In this paper, a new configuration for delta conversion UPS is proposed, which could help the system for better utilization of the UPS inverters. In this configuration, parallel and series inverters of the conventional delta conversion UPS, under the grid fault conditions, are connected in parallel which help to share the load power and this results in utilizing the series inverter during fault mode. Therefore, using this configuration not only decreases the total capacity of the UPS inverters, but also decreases the system total cost. In the proposed configuration, two inverters have the same sizes and specifications which results in the system modularity that simplifies its implementation and maintenance and reduces the manufacturing and life cycle cost of the UPS system. In addition, the proposed configuration increases the system reliability. To illustrate proper operation of the proposed configuration, some simulations are carried out under the different conditions. The given simulation results validate appropriate operation of the proposed configuration. [ABSTRACT FROM AUTHOR]

LLC resonant converter is one of the most suitable circuit topologies that have been introduced for designing constant output voltage switched-mode power supplies. In this paper, a design procedure is introduced for using this converter as a wide output range voltage source. Unlike constant output voltage applications which need small converter inductance ratio and narrow switching frequency variations, for wide output range applications, large values of these parameters are needed simultaneously and should be optimized. Instead of minimizing the components stresses, leading to a great value of the inductance ratio, proper choice of the converter parameters resulting in a smaller inductance ratio has been done. Maximum value of the capacitor in parallel with the power MOSFETs drain-sources has been derived to realize the zero voltage switching operation in the converter inductive region. Soft switching is achieved for all power devices under all operating conditions. A prototype of the converter has been tested for different regulated output voltages (35-165 Vdc) under different loads (0-3 Adc) and input voltages (320-370 Vdc) for using an ion implanter arc power supply, with maximum efficiency value of 94.7%. Experimental results confirm the high performance of the wide output range LLC resonant converter even under the worst case conditions. [ABSTRACT FROM AUTHOR]

LLC resonant converter with significant resonant inductance is proposed for designing an adjustable wide-range regulated voltage source. Large resonant inductance increases output voltage adjustment range and conversion efficiency, particularly at light loads. Soft switching is achieved for all power devices under all operating conditions by choosing the dead time and maximum switching frequency properly and operating in the converter's inductive region. Using a power-factor-correction (PFC) converter reduces the resonant converter's output voltage dependence to the variations of the main ac input voltage. Thus, the compensation of the load variations and the wide-range adjustment of the regulated output voltage can be achieved by using small switching frequency variations. The proposed method has been used to implement an adjustable wide-range voltage source (35–165 V dc), as an ion implanter arc power supply. An almost flat efficiency curve with maximum value of 94% has been achieved for the converter. Its output current can change from no load to 3 A dc. [ABSTRACT FROM AUTHOR]

LLC resonant converter has been widely used in dc–dc converters. In this paper, optimum dead-time and maximum switching frequency of a wide-adjustable-range LLC resonant converter are investigated for realizing the zero voltage switching (ZVS) operation even under the worst-case conditions. Analyses demonstrate that these parameters depend on the converter inductance ratio and ratio of the converter resonant capacitor and the effective capacitance appeared in parallel with the drain–sources of the power MOSFETs. The necessary dead time for realizing the ZVS operation can be minimized by choosing the normalized maximum switching frequency, properly. Using the dead-time optimum value, soft switching is achieved for all power devices even under the worst-case conditions. Developed prototype of the converter has been tested under different loads (0–3 A dc) and input voltage conditions (320–370 V dc) to achieve a wide-adjustable-range output voltage (40–165 V dc). This dc–dc converter is used as an ion implanter arc power supply. The calculated optimum dead-time and maximum switching frequency are approximately equal to 184 ns and 205.7 kHz, for realizing the ZVS operation at the worst-case conditions. These parameters in the prototype are approximately equal to 195 ns and 203.5 kHz, respectively. [ABSTRACT FROM PUBLISHER]

All-optical logic devices are essential for realizing all-optical signal processing. A full-adder is the basic building block of an arithmetic logic unit used in all-optical signal processing systems. In this paper, we aim to design an ultrafast and compact all-optical full-adder based on the photonic crystal. In this structure, three main inputs are connected to the three waveguides. Also, we have added one input waveguide to create symmetry in the structure and to improve the performance of the device. A linear point defect and two nonlinear rods of doped glass and chalcogenide are used to control the light behavior. The designed structure consists of 21×21 dielectric rods with a radius of 114 nm in a square cell and a lattice constant of 543.3 nm. Also, the area of the proposed structure is 130µ m 2 , and the maximum delay time of the proposed structure is about 1 ps, which indicates the minimum data rate of 1 THz. The maximum normalized power for low states and the minimum normalized power for high states are obtained as 25% and 75%, respectively. These characteristics make the proposed full-adder appropriate for high-speed data processing systems.

Objective: Iran has a low incidence of cervical cancer (CC). The country is introducing an organized screening system, including human papillomavirus screening. Studies show a high dropout rate among eligible women in continuing testing., Methods: This descriptive-analytic study was part of the first phase of a clinical trial conducted on a random sample of 400 women aged 18-49 in Andimeshk City, Khuzestan Province, in 2020. The data collection tool consisted of a man-made questionnaire that included domains of demographic characteristics, knowledge, attitude, practice, and self-efficacy in the Pap smear test. The data were analyzed with Stata-16 using linear and logistic regression models., Results: The mean knowledge, attitude, and self-efficacy scores were 6.80±2.33, 34.99±4.32, and 28.67±7.34, respectively. In the multiple models, every unit increase in the knowledge or attitude scores raised the mean self-efficacy score by 1.04 and 0.48, respectively (P<0.001). Every unit increase in the knowledge and self-efficacy scores increased the chance of performing Pap smear 1.61 and 1.41 times, respectively (P<0.001)., Conclusion: Given the association of women's knowledge and self-efficacy with practice in performing the Pap smear, it seems that an effective program promoting women's health behavior regarding CC screening would include applied education to raise community awareness and improve women's attitudes, self-efficacy, and practice.

Objective: Anemia is a major problem in developing countries, the purpose of the present study was to investigate the relationship between the human development index (HDI) and the prevalence of anemia among Asian women., Methods: This was a descriptive-analytic ecological study. The study analyzed data including HDI and prevalence of anemia extracted from the World Bank. The correlation coefficient and analysis of variance were used for data analysis. The significance level was considered to be less than 0.05. Analyses were performed using Stata-14 software., Results: The results revealed that the prevalence of anemia in women of reproductive age (R=-0.626, P<0.001), pregnant women (R=-0.576, P<0.001) and non-pregnant women (R=-0.623, P<0.0001) was significantly negatively correlated with HDI index. In the analysis of HDI components and the prevalence of anemia, a significant negative correlation was observed between the prevalence of anemia and the mean years of schooling, life expectancy at birth, and expected years of schooling indices in all 3 groups of women (non-pregnant, pregnant, and of reproductive age) (P<0.05)., Conclusion: Since there was a negative correlation between the prevalence of anemia in women and HDI, paying greater attention to factors which influence anemia may contribute to the prevention of anemia in developing countries.

Objective: Pancreatic cancer is one of the leading causes of mortality in developed countries and a lethal malignant neoplasm worldwide. This study aims to evaluate the epidemiology of pancreatic cancer incidence and mortality and its relationship with HDI., Methods: This is a descriptive cross-sectional study that is based on cancer incidence data and cancer mortality rates derived from the GLOBOCAN in 2018. The incidence and mortality rates of Pancreas as well as Pancreas cancer distribution maps were derived for world countries. The data analysis was conducted using a correlation test, and regression tests were used to evaluate the correlation of the incidence and mortality of Pancreas with HDI. The statistical analysis was carried out by Stata-14, and a significance level of 0.05 was considered., Results: The highest incidence of pancreatic cancer was reported in Asia with 214499 (46.7%) cases and the lowest incidence was related to Oceania with 4529 cases (0.99%). The results showed a positive and significant correlation between incidence (r = 0.764, P <0.0001) and mortality (r = 0.771, P <0.0001) of pancreatic cancer and the HDI index. The results of ANOVA revealed that the highest mean incidence was related to the very high HDI (P <0.0001) and the highest mortality was connected to the very high human development (P <0.0001). The results exhibited that incidence was positively and significantly correlated with GNI (r = 0.497, P <0.0001), MYS (r = 0.746, P <0.0001), LEB (r = 0.676, <0.0001) and EYS (r = 0.738, P <0.0001). Also, a significant positive correlation was found between mortality and GNI (r = 0.507, P <0.0001), MYS (r = 0.745, P <0.0001), LEB (r = 0.679, <0.0001), and EYS (r = 0.748, P <0.0001)., Conclusion: Given the higher incidence and mortality of pancreatic cancer in countries with HDI, it is necessary to pay a greater attention to risk factors and appropriate planning to reduce these factors and minimize the impact and mortality rate of this disease., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Tuberculosis (TB) spread pattern is influenced by geographic and social factors. Nowadays Geographic Information System (GIS) is one of the most important epidemiological instrumentation identifying high-risk population groups and geographic areas of TB. The aim of this study was to determine the correlation between climate and geographic distribution of TB in Khuzestan Province using GIS during 2005-2012., Methods: Through an ecological study, all 6363 patients with definite diagnosis of TB from 2005 until the end of September 2012 in Khuzestan Province, southern Iran were diagnosed. Data were recorded using TB- Register software. Tuberculosis incidence based on the climate and the average of annual rain was evaluated using GIS. Data were analyzed through SPSS software. Independent t-test, ANOVA, Linear regression, Pearson and Eta correlation coefficient with a significance level of less than 5% were used for the statistical analysis., Results: The TB incidence was different in various geographic conditions. The highest mean of TB cumulative incidence rate was observed in extra dry areas (P= 0.017). There was a significant inverse correlation between annual rain rate and TB incidence rate (R= -0.45, P= 0.001). The lowest TB incidence rate (0-100 cases per 100,000) was in areas with the average of annual rain more than 1000 mm (P= 0.003)., Conclusion: The risk of TB has a strong relationship with climate and the average of annual rain, so that the risk of TB in areas with low annual rainfall and extra dry climate is more than other regions. Services and special cares to high-risk regions of TB are recommended.