Effect of Varying Concentrations of Auxin (2,4-D) on In vitro Callus Initiation Using Leaf of Artemisia annua (L)

Study was carried out to determine the effect of varying concentrations of auxin on callus initiation using the leaves Artemisia annua as explants which were sterilized and inoculated into Murashig and Skoog basal medium supplemented with varying concentrations of 2,4-Dichlorophenoxy acetic acid (2,4-D) and incubated in the growth chamber for 4 weeks at 27ºc. Best results were obtained with 1.0 μm/l and 1.5 μm/l concentrations. Analysis of variance (ANOVA) indicated significant difference among all the treatments (P<0.05) on the parameters studied compared with the control. Consequently, 1.0 μm/l and 1.5 μm/l concentrations of 2,4-D are ideal for callus initiation in A. annua. This provides the means to mass propagation of A. annua through callus initiation and subsequent provision of raw materials required for artemisinin extraction.Keywords: Artemisia annua, Callus, Auxin, In vitro, 2,4- Dichlorophenoxy acetic acid (2,4-D

Quantification of Rain Induced Artifacts on Digital Satellite Television Reception

The presence of artifacts on the high definition television (TV) content and the eventual loss of the digital TV signals to rain is still a major concern to satellite operators, digital satellite television (DSTV) and terrestrial television content providers. In this paper, the artifacts present in a typical DSTV signal is examined on a practical direct-to-home (DTH) link at Osun State University, Osogbo, Nigeria (7.77°N, 4.60°E), received via EUTELSAT W4/W7 at 12.245 GHz. The degrading effect is assessed using a subjective experimental approach, which is based on the quantification of the artifacts ruining user’s Quality of Experience (QoE) during rainfall events. Results indicate that the thunderstorm rainfall is accountable for the impairment, while pixilation was observed as a dominant artifact appearing before the loss and shortly at the recovery of the DSTV signal.http://dx.doi.org/10.4314/njt.v34i4.1

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Triple-band CPW-FED planar monopole antenna for WLAN/WiMax application

A triple-band planar monopole antenna is presented in this article. The antenna consists of three strips which correspond to operating frequency bands of 2.4, 3.5, and 5.8 GHz. The proposed antenna has been designed, simulated, and fabricated on 20 × 38 mm2 FR4 board. There is good agreement between simulation and measurement results in terms of return loss and radiation pattern. The proposed antenna provides measured -10 dB bandwidths of 200 MHz for the 2.4 GHz (from 2.36 to 2.56 GHz); 620 MHz for the 3.5 GHz (from 3.48 to 4.10 GHz); and 1.38 GHz for 5.8 GHz (from 5.65 to 7.03 GHz). Moreover, the antenna provides the measured gain of 4.73, 1.66, and 3.28 dBi for 2.4, 3.5, and 5.8 GHz, respectively. The radiation characteristics have proven that the proposed antenna seems to be a good potential candidate for WLAN/WiMAX applications. © 2013 Wiley Periodicals, Inc

Radiation characteristics improvement of monopole antenna for WBAN applications

The design, simulation and fabrication of a P-shaped monopole antenna for wireless body area networks (WBAN) applications is presented in this paper. It is noted that the radiation characteristics was improved by attaching a P-shaped element to the ground plane. The simulation of the proposed antenna in the free space and close proximity of body surface has been done using CST Microwave Studio. The proposed antenna is designed on the FR4 substrate with dielectric constant of 4.4 and 1.6mm thickness; and the operating frequency band is between 3.1 to 5.1GHz. The final optimized design has dimensions of 32mm ×28mm. The proposed antenna improves the gain of close proximity of body surface. In addition, the antenna improves the reflection coefficient when placed close human body compared to other antennas. It was observed that there is good agreement between the simulation and measurement results, thereby showing that the antenna is potential to be deployed for WBAN application. © 2014 SERSC

An improved Itu-R rain attenuation prediction model over terrestrial microwave links in tropical region

An improved approach of predicting rain attenuation cumulative distribution (CD) over terrestrial microwave links operating in tropical regions is presented in this article. The proposed method offers a better extrapolation approach for determining the values of rain attenuation at different exceedance probability from the measured attenuation at 0.01% of the time. The experimental data consist of measured rainfall rates and rain attenuation over six geographically spread DIGI MINI-LINKs operating at 15 GHz in Malaysia. A new set of numerical coefficients was derived for improved rain attenuation CD predictions in the Malaysian tropical climate. In order to test the applicability of the proposed extrapolation method, a validation was performed using rain rate and rain attenuation measurements from five Brazilian and seven Nigerian tropical locations. When tested against measurements, the proposed method seems to provide a significant improvement over the current extrapolation method adopted by ITU-R Recommendations P.530-14, for the prediction of rain attenuation CD over tropical regions

Rain attenuation and worst month statistics verification and modeling for 5G radio link system at 26 GHz in Malaysia

The explosive daily dependence on wireless communication services necessitates the research to establish ultrawideband communication systems with ultrahigh bit rate transmission capabilities. The advent of the fifth-generation (5G) microwave link transmitting at millimeter-wave (mm-wave) frequency band is a promising technology to accommodate the escalating demand for wireless services. In this frequency band, however, the behavior of the transmission channel and its climatic properties are a major concern. This is of particular importance in tropical regions where the climate is mainly rainy with large raindrop size and high rainfall rate that may interact destructively with the propagating signal and cause total attenuation for the signal. International Telecommunication Union (ITU) introduced a global rain attenuation model to characterize the effect of rain on the propagating signal at a wideband of frequencies. The validity of this model in tropical regions is still an open question for research. In this paper, real measurements are conducted at Universiti Teknologi Malaysia (UTM), Johor Bahru, Malaysia, to investigate the impact of rain on the propagation of mm-waves at 26 GHz over the microwave 5G radio link system. Rainfall rate and rain attenuation data sets are collected for one year at one sample per min sampling rate. Both data sets are used to estimate signal propagation conditions in comparison to the ITU model prediction. From the presented results, it is found that at 0.01% percentage of time and rainfall rate of about 120 mm/hr, the propagated signal would experience 26.2 dB losses per kilometer traveled. In addition, there is a significant deviation between the empirical estimation of the worst month parameters and the ITU worst month parameter prediction. Similarly, rainfall rate and rain attenuation estimated through the ITU model imposes a large deviation as compared with the measurements. Furthermore, more accurate empirical worst month parameters are proposed that yielded more accurate estimation of the worst month rainfall and rain attenuation predictions in comparison to the ITU model predictions