Design of frequency selective limiting circuit

This paper explains the design of frequencyselective limiting circuit. The circuit is typically based on nonlinear matched reflection-mode bandstop resonator. This type of Frequency Selective Limiters achieves fast switching, high-level of power limiting, and flexible channel bandwidth. For single channel limiting, a device with one resonator (first order) produced a band-stop response centred at 2 GHz with 250 MHz of limiting bandwidth, 0 dBm limiting threshold, and 32 dB limiting level and it gave an all-pass response with less than 2.5 dB insertion loss at low RF powers. Multi-resonator filter has been used in order to improve the performance of the device. The prototype will produce intermodulation distortions and response time. Simulated results show an excellent highly selective bandstop performance at high powers with a near all-pass response at low signal powers

Windstorm hazardous area mapping using multi-criteria evaluation techniques of fuzzy logic approach.

The goal of this study to determine the most exposed area to windstorm event using fuzzy logic approach. Respond to the Sustainable Development Goal (SDG) 11 and 13, Sustainable Cities and Communities and Climate Action, this study was conducted to establish the preparedness in high-risk region. To achieve this goal, the influencing indicator was identified based on previous study. The related indicator comprises of wind speed, temperature, relative humidity, precipitation, slope, population, road, and land use. Fuzzy membership model implemented to aggregating the indicator to standard value 0 to 1. A fuzzy model was used as a method to integrate the constructed index values, and a frequency ratio was used to determine the fuzzy membership value. Different fuzzy operators (AND, OR, SUM, PRODUCT, and GAMMA) are applied to generate windstorm hazard map. The fuzzy gamma ( 3) operator, with γequal to 0.9, was used to create wind hazard map into different zones of five relative sensitivity classes: very high, high, moderate, low, and very low. 10.65% of study area has very high sensitivity towards windstorm hazard which distributed at high area (Banjaran titiwangsa), West Coast area (Pahang and West Johor) and north area (Perlis). In addition, some part in the surrounding region of Peninsular Malaysia were also identified as windstorm hazard due to the dense of urban area such at Johor Bharu and Klang Valley area. 7.20% of the study area has very-low windstorm hazard and is mainly located in the middle part

Analyzing windstorm pattern in Malaysia based on extracted Twitter data.

Wind-rain interactions often lead to severe windstorm events and consequently cause damages and fatal destructions. The increase in frequency of recent windstorm events overwhelmed the nation. Thus, efforts in obtaining and recording these events are intensified with the help of current technology. This study aims to analyze the pattern of recent windstorm events by utilizing big data and GIS. In this study, the reported windstorm events in Twitter application were extracted using R-programming. Prior to analyses, the extracted data were screened to remove any outliers found. The extracted data were selected based on the credibility of its sources to ensure the accuracy and quality. These selected data were extracted from trusted users such as Meteorological Department of Malaysia (MMD), Berita Harian, Bernama and others. This study has demonstrated the possibility of Twitter data as an alternative data source in windstorm studies based on its reasonable findings. It is exhibited that there is drastic increased of windstorm events frequency in years 2018-2020, especially in the northern and west-coast regions of Peninsular. The highest frequency was recorded in April (inter-monsoon season) while the lowest is in February and December (northeast monsoon). The increase of frequency in several locations in the Peninsular is very alarming especially in the Klang Valley since this region is highly populated and serves as Malaysia's important economic zones. Hence, risk control should be considered in this region to reduce the negative impacts as suggested in SDG11 and SDG13

Severe asymptomatic hypophosphataemia in a child with T-acute lymphoblastic leukaemia

Hypophosphataemia is a metabolic disorder that is commonly encountered in critically ill patients. Phosphate has many roles in physiological functions, thus the depletion of serum phosphate could lead to impairment in multiple organ systems, which include the respiratory, cardiovascular, neurological and muscular systems and haematological and metabolic functions. Hypophosphataemia is defined as plasma phosphate level below 0.80 mmol per litre (mmol/L) and can be further divided into subgroups of mild (plasma phosphate of 0.66 to 0.79 mmol/L), moderate (plasma phosphate of 0.32 to 0.65 mmol/L) and severe (plasma phosphate of less than 0.32 mmol/L). The causes of hypophosphataemia include inadequate phosphate intake, decreased intestinal absorption, gastrointestinal or renal phosphate loss, and redistribution of phosphate into cells. Symptomatic hypophosphataemia associated with haematological malignancies has been reported infrequently. We report here a case of asymptomatic severe hypophosphataemia in a child with acute T-cell lymphoblastic leukaemia. A 14-year-old Chinese boy was diagnosed to have acute T cell lymphoblastic leukaemia (ALL). His serum biochemistry results were normal except inorganic phosphate and lactate dehydrogenase levels. The serum inorganic phosphate level was 0.1mmol/L and the level was low on repeated analysis. The child had no symptoms related to low phosphate levels. The possible causes of low phosphate were ruled out and urine Tmp/GFR was normal. Chemotherapy regime was started and the serum phosphate levels started to increase. Hypophosphataemia in leukaemia was attributed to shift of phosphorus into leukemic cells and excessive cellular phosphate consumption by rapidly proliferating cells. Several reports of symptomatic hypophosphataemia in myelogenous and lymphoblastic leukaemia in adults have been reported. To our knowledge this is the first case of severe asymptomatic hypophosphataemia in a child with ALL

Estudio del microbioma intestinal en pacientes egipcios con colitis ulcerosa crónica idiopática

Resumen: Introducción y objetivo: La colitis ulcerosa crónica idiopática (CUCI) se caracteriza por una inflamación crónica e incontrolada de la mucosa intestinal. Se ha informado que la disbiosis del microbioma intestinal es un factor de inflamación intestinal. El objetivo del presente trabajo fue estudiar los cambios en el microbioma intestinal en pacientes egipcios con CUCI activa. Materiales y métodos: En este estudio transversal, se analizó el microbioma intestinal de 21 pacientes con CUCI y de 20 sujetos como grupo de control mediante la técnica de PCR cuantitativa SYBR Green en tiempo real dirigida al ARNr 16S de filos/géneros o especies bacterianas seleccionadas. Resultados: Los pacientes con CUCI mostraron una marcada disbiosis, evidenciada por una disminución significativa de las bacterias antiinflamatorias Firmicutes y F. prausnitzii. La relación Firmicutes/Bacteroidetes también fue menor en los casos de CUCI (1,65) en comparación con los controles sanos (2,93). Además, los casos de CUCI mostraron una disminución estadísticamente significativa en Ruminococcus en comparación con el grupo de control. Sin embargo, no hubo diferencia estadísticamente significativa entre los pacientes con CUCI y los casos de control en lo que respecta a A. muciniphila, Bifidobacterium, Lactobacillus, Bacteroides y Prevotella. Un caso de CUCI fue positivo a Clostridioides difficile, de baja abundancia relativa. Conclusión: El presente estudio mostró diferencias en el microbioma intestinal de los pacientes con CUCI en comparación con los controles sanos. Esto puede ayudar a identificar el microbioma intestinal y los cambios bacterianos específicos que pueden ser objeto de tratamiento de la CUCI. Abstract: Introduction and aim: Ulcerative colitis (UC) is characterized by chronic, uncontrolled inflammation of the intestinal mucosa. Gut microbiota dysbiosis was reported to be a factor in intestinal inflammation. The aim of the present study was to study changes in the gut microbiome in Egyptian patients with active UC. Materials and methods: In this cross-sectional study, the gut bacterial microbiome of 21 UC patients and 20 control subjects was analyzed using the quantitative SYBR Green real-time PCR technique, targeting the 16S rRNA gene of selected bacterial phyla/genera and/or species. Results: UC patients showed marked dysbiosis evidenced by a significant decrease in the Firmicutes and F. prausnitzii anti-inflammatory bacteria. The Firmicutes/Bacteroidetes ratio was also lower in the UC cases (1.65), compared with the healthy controls (2.93). In addition, the UC cases showed a statistically significant decrease in Ruminococcus, compared with the control group. However, there were no statistically significant differences between UC patients and the controls, regarding A. muciniphila, Bifidobacterium, Lactobacillus, Bacteroides, and Prevotella. One UC case was positive for the pathogenic bacterium, Clostridioides difficile, with low relative abundance. Conclusion: The current study showed differences in the gut microbiome of UC patients, compared with healthy controls. This may help in identifying the gut microbiome and specific bacterial changes that can be targeted for treatment of UC

Study of the gut microbiome in Egyptian patients with active ulcerative colitis

Introduction and aim: Ulcerative colitis (UC) is characterized by chronic, uncontrolled inflammation of the intestinal mucosa. Gut microbiota dysbiosis was reported to be a factor in intestinal inflammation. The aim of the present study was to study changes in the gut microbiome in Egyptian patients with active UC. Materials and methods: In this cross-sectional study, the gut bacterial microbiome of 21 UC patients and 20 control subjects was analyzed using the quantitative SYBR Green real-time PCR technique, targeting the 16S rRNA gene of selected bacterial phyla/genera and/or species. Results: UC patients showed marked dysbiosis evidenced by a significant decrease in the Firmicutes and F. prausnitzii anti-inflammatory bacteria. The Firmicutes/Bacteroidetes ratio was also lower in the UC cases (1.65), compared with the healthy controls (2.93). In addition, the UC cases showed a statistically significant decrease in Ruminococcus, compared with the control group. However, there were no statistically significant differences between UC patients and the controls, regarding A. muciniphila, Bifidobacterium, Lactobacillus, Bacteroides, and Prevotella. One UC case was positive for the pathogenic bacterium, Clostridioides difficile, with low relative abundance. Conclusion: The current study showed differences in the gut microbiome of UC patients, compared with healthy controls. This may help in identifying the gut microbiome and specific bacterial changes that can be targeted for treatment of UC. Resumen: Introducción y objetivo: La colitis ulcerosa crónica idiopática (CUCI) se caracteriza por una inflamación crónica e incontrolada de la mucosa intestinal. Se ha informado que la disbiosis del microbioma intestinal es un factor de inflamación intestinal. El objetivo del presente estudio fue estudiar los cambios en el microbioma intestinal en pacientes egipcios con CUCI activa. Materiales y métodos: En este estudio transversal, se analizó el microbioma intestinal de 21 pacientes con CUCI y 20 sujetos como grupo de control mediante la técnica de PCR cuantitativa SYBR Green en tiempo real dirigida al ARNr 16S de filos/géneros y/o especies bacterianas seleccionadas. Resultados: Los pacientes con CUCI mostraron una marcada disbiosis evidenciada por una disminución significativa de las bacterias antiinflamatorias Firmicutes y F. prausnitzii. La relación Firmicutes/Bacteroidetes también fue menor en los casos de CUCI (1,65), en comparación con los controles sanos (2,93). Además, los casos de CUCI mostraron una disminución estadísticamente significativa en Ruminococcus en comparación con el grupo de control. Sin embargo, no hubo diferencia estadísticamente significativa entre los pacientes con CUCI y los casos de control en lo que respecta a A. muciniphila, Bifidobacterium, Lactobacillus, Bacteroides y Prevotella. Un caso de CUCI fue positivo a Clostridioides difficile, de baja abundancia relativa. Conclusión: El presente estudio mostró diferencias en el microbioma intestinal de los pacientes con CUCI en comparación con los controles sanos. Esto puede ayudar a identificar el microbioma intestinal y los cambios bacterianos específicos que pueden ser objeto de tratamiento de la CUCI

A Computational Study on the Magnetic Resonance Coupling Technique for Wireless Power Transfer

Non-radiative wireless power transfer (WPT) system using magnetic resonance coupling (MRC) technique has recently been a topic of discussion among researchers. This technique discussed more scenarios in mid-range field of wireless power transmission reflected to the distance and efficiency. The WPT system efficiency varies when the coupling distance between two coils involved changes. This could lead to a decisive issue of high efficient power transfer. This paper presents case studies on the relationship of operating range with the efficiency of the MRC technique. Demonstrative WPT system operates at two different frequencies are projected in order to verify performance. The resonance frequencies used are less than 100MHz within range of 10cm to 20cm

A Computational Study on the Magnetic Resonance Coupling Technique for Wireless Power Transfer

Non-radiative wireless power transfer (WPT) system using magnetic resonance coupling (MRC) technique has recently been a topic of discussion among researchers. This technique discussed more scenarios in mid-range field of wireless power transmission reflected to the distance and efficiency. The WPT system efficiency varies when the coupling distance between two coils involved changes. This could lead to a decisive issue of high efficient power transfer. This paper presents case studies on the relationship of operating range with the efficiency of the MRC technique. Demonstrative WPT system operates at two different frequencies are projected in order to verify performance. The resonance frequencies used are less than 100MHz within range of 10cm to 20cm

Design of Frequency Limiting Circuit Based on Nonlinear Matched Reflection-Mode Bandstop Resonator

This paper presents the design of frequency selective limiting circuit based on nonlinear matched reflectionmode bandstop resonator. This type of Frequency Selective Limiters (FSL) can achieve fast switching, high-level of power limiting, and flexible channel bandwidth as well as has the ability to protect the sensitive circuitry against large interfering signals. A prototype first-degree frequency selective limiting circuit based on bandstop response is proposed and designed. The circuit has the center frequency of 2.4 GHz and is implemented on an FR4 substrate with a thickness of 1.6 mm and dielectric constant (εr) of 4.7. Experimental results show excellent agreement with simulated performance. This new class of FSL would be useful in microwave systems such as in wideband electronic warfare receiver as multi-channel band-stop filters

Measurement of photoelectron generation in a gold coated glass slide

In thin low-Z media irradiated by photon energies of several tens of keV, the presence of a high-Z additive can result in manifest locally modified secondary electron dose. Present study analyses the photoelectron dose enhancement resulting from nanometre thickness gold (atomic number Z = 78) coated on commercial borosilicate (B2O3) glass microscope cover-slips. Two thicknesses of B2O3 cover-slip have been utilized, 0.13 ± 0.02 mm and 1.00 ± 0.01 mm, with single-sided Au coatings of 20, 40, 60, 80 and 100 nm. An additional uncoated glass slide has been kept as a comparator. The samples have been exposed to X-rays generated at kVp potentials, delivering a fixed dose of 2 Gy. Dose enhancement resulting from the 1.00 mm glass has been observed to be ~1.32 × that of the 0.13 mm thickness glass. The elemental composition of the samples has been obtained via Electron Dispersive X-ray (EDX), elemental content differences between the two thicknesses of glass leading to a difference in effective atomic number of less than 0.3%. The influence on photon yield of the gold coating and variations in elemental content has been modelled using Monte Carlo simulation, allowing comparison with the measured values of enhanced TL yield