Nature-inspired Cuckoo Search Algorithm for Side Lobe Suppression in a Symmetric Linear Antenna Array

In this paper, we proposed a newly modified cuckoo search (MCS) algorithm integrated with the Roulette wheel selection operator and the inertia weight controlling the search ability towards synthesizing symmetric linear array geometry with minimum side lobe level (SLL) and/or nulls control. The basic cuckoo search (CS) algorithm is primarily based on the natural obligate brood parasitic behavior of some cuckoo species in combination with the Levy flight behavior of some birds and fruit flies. The CS metaheuristic approach is straightforward and capable of solving effectively general N-dimensional, linear and nonlinear optimization problems. The array geometry synthesis is first formulated as an optimization problem with the goal of SLL suppression and/or null prescribed placement in certain directions, and then solved by the newly MCS algorithm for the optimum element or isotropic radiator locations in the azimuth-plane or xy-plane. The study also focuses on the four internal parameters of MCS algorithm specifically on their implicit effects in the array synthesis. The optimal inter-element spacing solutions obtained by the MCS-optimizer are validated through comparisons with the standard CS-optimizer and the conventional array within the uniform and the Dolph-Chebyshev envelope patterns using MATLABTM. Finally, we also compared the fine-tuned MCS algorithm with two popular evolutionary algorithm (EA) techniques include particle swarm optimization (PSO) and genetic algorithms (GA)

Low Noise, High Gain RF Front End Receiver at 5.8GHz for WiMAX Application

This paper presents the design of a high gain, low noise direct conversion Radio frequency(RF) front-end receiver system. The Front end receiver is designed to operate at 5.8 GHz in compliant with IEEE 802.16 WiMAX standard. The system consists of a low noise amplifier (LNA), a radio frequency amplifier (RFA), a power divider and two band pass filters. The design process involved the use of software such as ADS 2000A, Ansoft Designer and MathCad. FET FHX76 LP is used in the design of the LNA due to its low noise figure and high impedance input. As for the RFA design,FET EPA018A was used. The LNA and the RFA used T lumped reactive element network and microstrip line matching network. Two 3 dBπ -attenuators were inserted at the input and output of the RFA to isolate the system from the reflected load power. A Wilkinson power divider is developed for two equal power structures using impedance microstrip line technique. Microstrip technology was used for designing the Chebyshev filter. The result of each module for the front end is presented

Helicobacter Pylori Infection in Superficial Gastritis, Erosive Gastritis and Gastric Ulcer

Background: Helicobacter pylori (H. pylori) infection leads to inflammation of the gastric mucosa. It damages the gastric epithelium and related to the risk of developing gastric cancer. Over time, it may develop into the development of glandular atrophy and intestinal metaplasia. This study was aimed to evaluate the histological features of gastric mucosa, including H. pylori infection in patients with endoscopically found superficial gastritis, erosive gastritis and gastric ulcer. Method: Subjects with abdominal complaints who underwent consecutive upper gastrointestinal endoscopy were prospectively selected at Tugurejo Hospital between November 2004 and December 2010. Eligible subjects were those with endoscopic diagnosis of superficial gastritis, erosive gastritis or gastric ulcer. The biopsy specimens were taken from the corpus, angulus and antrum of all the patients. Giemsa and hematoxylin-eosin staining were used for the histological diagnosis H. pylori and gastric mucosa inflammation. Results: The overall prevalence of H. pylori infection in superficial gastritis, erosive gastritis and gastric ulcer were 24.3%. There was significant difference between H. pylori infection rate in antrum of patients with superficial gastritis 19.4%, erosive gastritis 26.3%, and gastric ulcer 34.7%. The positivity rate of glandular atrophy and intestinal metaplasia of superficial gastritis with H. pylori- positivity was 12.5%, 14.0%; erosive gastritis 26.3%, 16.6%; and of gastric ulcer 38.9%, 29.3%; respectively. However, there was no significant difference. Conclusion: Patients with gastric ulcer have H. pylori infection, atrophic gastritis and metaplasia intestinal more than superficial gastritis and erosive gastritis. Progression of the gastric ulcer to atrophic gastritis and intestinal metaplasia is related to H. pylori infection

Influence of Fucoidan in Mucus Thickness of Gastric Mucosa in Patients with Chronic Gastritis

Background: Chronic gastritis is commonly found with complains of dyspepsia, which may decrease work productivity. Imbalance between agressive and defensive factors is the cause of chronic gastritis. Therapy is mostly directed to the agressive factors, particularly gastric acid and very few studies are directed on defensive factors. Mucus is the first defense mechanism of gastric mucosa. Fucoidan is a phytopharmaca, which is thought to increase the thickness of gastric mucosa. The objective of this study was to know the thickness of gastric mucosa in patients with chronic gastritis and to evaluate the effect of fucoidan to the gastric mucosa thickness in patients with chronic gastritis. Method: In this double-blinded randomized clinical trial study, 41 patients in the Endoscopy Unit Cipto Mangunkusumo Hospital between October 2009 and October 2010 were enrolled consecutively. Selected patients were divided into 2 groups: a group was given fucoidan and another group was given placebo. Statistical analysis was done using T-test. Results: Of 41 chronic gastritis patients, only 34 patients completed this study. There was difference of mucus thickness of gastric mucosa in patients with chronic gastritis; in the antrum 42.59 µ m (± 8.67) and in the corpus 44.28 µ m (± 9.64). This study also showed that fucoidan administration increased the mucus thickness in the antrum by 7.42 µ m and in the corpus by 7.74 µ m compared to placebo significantly. Conclusion: Fucoidan increased the mucus thickness of gastric mucosa in patients with chronic gastritis

Life Style Factors Influencing Serum Pepsinogen Levels in Healthy Japanese: a Prospective Study

Background: Gastric cancer mass screening using serum pepsinogen has been recognized and several advantages of this methods over photofluorography have been shown by previous study. Aims: To determine the factors influence the serum pepsinogen levels in healthy subjects. Subjects & Methods: One thousand and one hundred fourteen subjects who were screened for gastric cancer as part of a periodic health check. Blood samples were taken after fasting and stored below –20 ° C, until pepsinogen levels were assayed. Results: The subjects consist of 338 males (mean age 52.6+14.0) and 776 females (mean age 49.0+11.9). Age ranges from 19 to 81 years. The overall prevalence of chronic atrophic gastritis using a criterion PG I £ 70 hg/ml and PG I/II ratio £ 3.0 was 21.99 % in 1996 and 23.97 % in 2000. Bivariate analysis revealed a significant association between age, more salt consumption, fish favorable over meat and less than three time meal intake covariates with the lowering of PG I/II ratio. Smoking, drinking, BMI, weight and gender did not affect the changes of PG I/II ratio. Conclusion: Age and more salt consumption covariates have a strongest association with the decreased of PG I/II by multivariate analysis

The utility of 1-minute sit-to-stand test to detect exercise-induced oxygen desaturation in outpatient assessment of post COVID-19 patients.

Introduction: The 6-min walk test (6MWT) is the gold standard for assessing exercise-induced impairment of gas exchange, but it is technically challenging in a busy outpatient clinic. The aim of this study was to compare the 1-min sit-to-stand test (1STST) with the 6MWT in assessment of exercise-induced oxygen desaturation in post COVID-19 patients in an outpatient setting. Methods: A total of 447 outpatient post COVID-19 patients were recruited from post COVID-19 clinic. Both 6MWT and 1STST (a set) were performed on the same day including pulse oxygen saturation (SpO2) recording at baseline, nadir, and recovery stage. Results: A total of 447 sets were performed at a mean of 160 days post discharge. Majority were in category severe (n=251, 56%), critical (n=118, 26%) and moderate (n=6, 15%). At assessment, most patients were symptomatic (mMRC > 2) n= 258, 58%. There was no significant difference between nadir SpO2 for 6MWT and 1STST (p 4% oxygen desaturation compared with 6MWT (table 1). There was also correlation between 6MWT distance and 1STST repetition; R=0.144 p<0.002. Conclusion: Both 6MWT and 1STS have good agreement on nadir SpO2 and are sensitive to detect > 4% oxygen desaturation. Therefore, 1STST is an useful screening test to detect exercise-induced oxygen desaturation during outpatient assessment

Spirometry outcomes in survivors of COVID-19 pneumonia

Introduction: Acute COVID-19 infection could lead to long COVID, a heterogenous condition which includes the respiratory system. But data on long-term respiratory complications are scarce and limited especially from our part of the world. Methods: A total of 443 post COVID-19 patients were recruited from post COVID-19 clinic. The following assessments were performed in all patients; symptoms, 6-minute-walk-test (6MWT), 1-minute-sit-to-stand-test (1STST), spirometry, and chest radiograph. Results: Patient’s mean age was 51 (13) years old, majority were male (60%), and Malay ethnicity (73%). Majority were in category severe (n=254, 57%), critical (n=122, 28%) and moderate (n=67, 15%). Abnormal spirometry (FVC 4% during 6MWT and 1STST, OR 1.8 (1.1-2.9) and OR 1.7 (1.1-2.6) respectively, and abnormal chest radiograph, OR 3.9 (2.5-6.2) compared to those with normal spirometry findings. 125 patients have full lung function test and gas transfer done which showed reduced TLC (80%) in majority of cases; 80% (n = 100), 86.4% (n = 108) and 94% (n = 117). Conclusion: Abnormal spirometry findings are common among post COVID-19 patients with pneumonia and are associated with poorer respiratory outcomes; exertional oxygen desaturation and abnormal chest radiograph. Therefore, these groups of patients should be referred for spirometry assessmen

Simulation Of Cascading LNA And RF Amplifier For Front-End Direct-Conversion Receiver At 5.8 GHz

In this paper, a simulation of cascaded LNA and RF amplifier for front-end direct conversion receiver at 5.8-GHz frequency band is presented. By using direct conversion architecture, the image rejection performance is improved, lower complexity and the component is reduced. The cascading LNA and RF amplifier has 27 dB gain and 2.17 dB noise figure. The LNA and RF amplifier is simulated using Ansoft Designer software and fabricated with Duroid 5880 as the microstrip material

Demographical Distribution on the Incidence of Helicobacter Pylori Infection in Jakarta: Obtaining Samples From 5 Municipalities

Background: Currently, the hospital-based studies on Helicobacter pylori (H. pylori) have demonstrated that the incidence of H. pylori infection tends to decline in Indonesia. On the other hand, no population-based study has ever been conducted. Therefore, our study was performed to evaluate the true incidence of H. pylori found among the population.Method: This study was a surveillance using cross-sectional design. The samples used in our study were randomly selected from 1,645 samples including those from five municapalities of Special Capital Region of Jakarta in 2006. Immunochromatographic test (ICT) was utilized to establish the diagnosis of H. pylori infection. The test has demonstrated high sensitivity and specificity for Indonesian populationResults: The seroprevalence of H. pylori infection among 310 patients was 52.3% (162 out of 310 patients) with mean age of 43.48 + 10.45 years. There was no difference regarding seroprevalence in both groups of &lt; 40 year and &gt; 40 years of age (52.3% and 52.2%). The highest prevalence of H. pylori infection was found in West Jakarta (66.1%); while the lowest prevalence was found in South Jakarta (41.0%). The incidence of H.pylori infection between those who were alcoholic was equal to those who were not alcoholic (46.2% vs. 52.5%).Similar result was also found between smokers and non-smokers (53.8% vs. 51.8%).Conclusion: In this study, we found that H. pylori seroprevalence remains high in the population. Various seroprevalence of H.pylori infection were found among five municipalities in Jakarta