Geometry Modification Assessment and Design Optimization of Miniaturized Wideband Antennas

Maintaining small physical dimensions of antenna structures is an important consideration for contemporary wireless communication systems. Typically, antenna miniaturization is achieved through various topological modifications of the basic antenna geometries. The modifications can be applied to the ground plane, the feed line, and/or antenna radiator. Unfortunately, various topology alteration options are normally reported on a case-to-case basis. The literature is lacking systematic investigations or comparisons of different modification methods and their effects on antenna miniaturization rate as well as electrical performance. Another critical issue—apart from setting up the antenna topology—is a proper adjustment of geometry parameters of the structure so that the optimum design can be identified. Majority of researchers utilize experience-driven parameter sweeping which typically yields designs that are acceptable, but definitely not optimal. Furthermore, in many of the cases, the authors provide a cooperative progression before and after topological modifications that generally lead to a certain reduction of the antenna size, however, with appropriate parameter adjustment missing. Consequently, suitability of particular modifications in the miniaturization context is not conclusively assessed. In order to carry out such an assessment in a reliable manner, identification of the truly optimum design is necessary. This requires rigorous numerical optimization of all antenna parameters (especially in the case of complex antenna topologies) with the primary objective being size reduction, and supplementary constraints imposed on selected electrical or field characteristics. This thesis is an attempt to carry out systematic investigations concerning the relevance of geometry modifications in the context of wideband antenna miniaturization. The studies are carried out based on selected benchmark sets of wideband antennas. In order to ensure a fair comparison, all geometry parameters are rigorously tuned through EM-driven optimization to obtain the minimum footprint while maintaining acceptable electrical performance. The results demonstrate that it is possible to conclusively distinguish certain classes of topology alterations that are generally advantageous in the context of size reduction, as well as quantify the benefits of modifications applied to various parts of the antenna structure, e.g., with feed line modifications being more efficient than the ground plane and radiator ones. Several counterexamples have been discussed as well, indicating that certain modifications can be counterproductive when introduced ad hoc and without proper parameter tuning. The results of these investigations have been utilized to design several instances of novel compact wideband antennas with the focus on isolation improvement and overall antenna size reduction in multi-input-multi-output (MIMO) systems. Experimental validations confirming the numerical findings are also provided. To the best of the author’s knowledge, the presented study is the first systematic investigation of this kind in the literature and can be considered a step towards the development of better, low-cost, and more compact antennas for wireless communication systems.Fyrir þráðlaus fjarskiptakerfi er mikilvægt að tryggja að loftnet séu lítil að umfangi. Yfirleitt er smækkun loftneta náð með ýmis konar formbreytingum á grunngerðum þeirra. Formbreytingarnar geta verið á jarðtengingu, fæðilínu og / eða geislagjafa. Því miður er venjulega einungis sagt frá slíkum formbreytingum fyrir einstaka tilvik. Skortur er á kerfisbundnu mati og samanburði á mismunandi formbreytingum og hvaða áhrif þær hafa á smækkun og raffræðilega eiginleika loftneta. Annað mikilvægt atriði, fyrir utan að ákveða gerð formbreytingarinnar, er að velja stika sem lýsa nákvæmri lögun svo að bestuð hönnun geti átt sér stað. Flestir hönnuðir notast við þá aðferð að notast við stikaskimun sem byggir á reynslugögnum, en sú aðferð skilar almennt ásættanlegri hönnun, þó ekki bestaðri. Einnig er í mörgum tilvikum sagt frá samhliða þróun fyrir og eftir formbreytingu sem leiðir til smækkunar án þess að tilgreina breytingar á stikum. Fyrir vikið er erfitt að meta til hlítar ávinning af mismunandi formbreytingum. Til þess að framkvæma slíkt mat með áreiðanlegum hætti er nauðsynlegt að geta metið bestu hönnunarútfærslu nákvæmlega. Þetta kallar á ítarlega tölulega bestun allra stika sem lýsa loftnetinu (einkum fyrir loftnet flókinnar lögunnar) þar sem aðalmarkmkið bestunar er smækkun en skorður eru settar af raffræðilegum eiginleikum. Í þessari ritgerð er leitast við að kerfisbundna rannsókn á mikilvægi formbreytingna í tengslum við smækkun bandbreiðra loftneta. Rannsóknin byggir á völdum söfnum viðmiðunarloftneta. Til að tryggja rétt mat eru allir stikar er varða lögun stilltir með rafsegulfræðilegri hermun til að tryggja minnst rúmtak með ásættanlegum raffræðilegum eiginleikum. Niðurstöðurnar sýna að unnt er að greina, án vafa, ákveðna flokka formbreytinga sem eru að jafnaði til þess fallnir að smækka loftnet. Auk þessa er hægt að reikna ávinning af formbreytingum mismunandi hluta loftnetsins, t.d. að breytingar á fæðilínu eru almennt hagkvæmari en breytingar á geislagjafa eða jarðtengingu. Þá er greint frá nokkrum tilvikum þar sem tilfallandi formbreytingar geta verið til tjóns ef ekki stikaval er ekki gert með réttum hætti. Niðurstöður þessara rannsóknar hafa verið notaðar til að hanna nokkur nýstárleg breiðbandsloftnet með áherslu á smækkun og bættan aðskilnað fjölgátta (MIMO) loftneta. Töluleg hermun er sannreynd með tilraunum. Að bestu vitund höfundar er hér um fyrstu kerfisbundnu rannsókn þessarar gerðar að ræða og má reikna með að hún leiði til þróunar betri, ódýrari og smærri loftneta fyrir þráðlaus fjarskiptakerfi.The Ph.D. project was supported by the Icelandic Research Center (RANNIS) Grant 16329905

Fear of getting Covid-19: A challenge to elective surgical practice and ways to overcome

Background: Covid-19, a global pandemic has a huge impact on surgical practice. There is transmission risk of Covid-19 during the elective surgery and nowadays it is a part of informed consent process. This has an impact on patient decision making as it creates anxiety and fear. Objective: To evaluate patient experience (fear of getting Covid-19) from elective surgery and challenges of elective surgical practice and ways to overcome during this pandemic era. Methods: This study was an observational cross-sectional survey and it has been conducted in General Surgery Department of Dr Akbar Niazi Teaching Hospital, Islamabad, from May to August 2021 after approval of Institutional Review Board (IRB). Participants for elective surgery and their negative report of Covid-19 infection by polymerase chain reaction (PCR) were included in the study. Fear of Covid-19 infection was measured through “fear of Covid-19 scale” by Ahorsu et al and analyzed. All findings were entered in a structured Proforma. Data was entered in SPSS version 26 and analyzed. Effect modifier chi square was used to find out the patient’s dropout due to getting Covid-19 infection from surgery. Results: Total 200 patients were included; 62% patients were male and 38% were females. The mean age of the patients was 38.64±12.08 years. The statistical analysis showed that there was a very significant association between FCV-19 scale and getting Covid-19 infection from elective surgeries (p ≤ 0.05). When stratified FCV-19 scale with education status of all patients there was a very significant association between them (p=0.001). The patient’s observations regarding FCV-19 questionnaire, most of the patients were disagreed (46.3%) to getting Covid-19 infection from their elective surgeries or any fear of Covid-19 infection. The actual dropout of patients from elective surgery due to fear of getting Covid-19 infection during surgery or staying in hospital was 7.5%. Conclusion: Fear of getting Covid-19 is still present in some of the patients who visit hospitals for elective surgeries. Discussing the various steps taken by the institute to improve patient safety and minimize risk of Covid-19, greatly enhanced their confidence in elective surgery and improved satisfaction level. Key words: Covid-19; Fear; Fear of Covid-19 Scale; Elective Surgical Procedures

Fear of getting Covid-19: A challenge to elective surgical practice and ways to overcome

Background: Covid-19, a global pandemic has a huge impact on surgical practice. There is transmission risk of Covid-19 during the elective surgery and nowadays it is a part of informed consent process. This has an impact on patient decision making as it creates anxiety and fear. Objective: To evaluate patient experience (fear of getting Covid-19) from elective surgery and challenges of elective surgical practice and ways to overcome during this pandemic era. Methods: This study was an observational cross-sectional survey and it has been conducted in General Surgery Department of Dr Akbar Niazi Teaching Hospital, Islamabad, from May to August 2021 after approval of Institutional Review Board (IRB). Participants for elective surgery and their negative report of Covid-19 infection by polymerase chain reaction (PCR) were included in the study. Fear of Covid-19 infection was measured through “fear of Covid-19 scale” by Ahorsu et al and analyzed. All findings were entered in a structured Proforma. Data was entered in SPSS version 26 and analyzed. Effect modifier chi square was used to find out the patient’s dropout due to getting Covid-19 infection from surgery. Results: Total 200 patients were included; 62% patients were male and 38% were females. The mean age of the patients was 38.64±12.08 years. The statistical analysis showed that there was a very significant association between FCV-19 scale and getting Covid-19 infection from elective surgeries (p ≤ 0.05). When stratified FCV-19 scale with education status of all patients there was a very significant association between them (p=0.001). The patient’s observations regarding FCV-19 questionnaire, most of the patients were disagreed (46.3%) to getting Covid-19 infection from their elective surgeries or any fear of Covid-19 infection. The actual dropout of patients from elective surgery due to fear of getting Covid-19 infection during surgery or staying in hospital was 7.5%. Conclusion: Fear of getting Covid-19 is still present in some of the patients who visit hospitals for elective surgeries. Discussing the various steps taken by the institute to improve patient safety and minimize risk of Covid-19, greatly enhanced their confidence in elective surgery and improved satisfaction level. Key words: Covid-19; Fear; Fear of Covid-19 Scale; Elective Surgical Procedures

Potential of siltstone and its composites with biochar and magnetite nanoparticles for the removal of cadmium from contaminated aqueous solutions: Batch and column scale studies

© 2020 Elsevier Ltd The present study is the first attempt to evaluate the pilot and batch scale adsorption potential of siltstone (SS) and its nanocomposites with biochar (EDB/SS), magnetite nanoparticles (MNPs/SS) and MNPs/EDB/SS for Cd removal from contaminated water. The SS, EDB/SS, MNPs/SS and MNPs/EDB/SS were characterized with FTIR, XRD, BET, SEM, TEM, TGA and point of zero charge (PZC). The effects of adsorbent dosage, contact time, initial Cd concentration, pH and presence of competing ions were evaluated on the Cd removal and its adsorption. The order for Cd removal was: MNPs/EDB/SS \u3e MNPs/SS \u3e EDB/SS \u3e SS (95.86–99.72% \u3e 93.10–98.5% \u3e 89.66.98–98.40% \u3e 74.90–90%). Column scale experiments yielded maximum retention (95%) of Cd even after 2 h of injection at 100 mg Cd/L. The exhausted SS, EDB/SS, MNPs/SS and MNPs/EDB/SS were reused without losing significant adsorption potential. Similarly, maximum Cd adsorption (117.38 mg/g) was obtained with MNPs/EDB/SS at dose 1.0 g/L. The results revealed that coexisting cations reduced the Cd removal due to competition with Cd ions. The experimental results were better explained with Freundlich isotherm model and pseudo 2nd order kinetic models. The results revealed that SS and its composites can be used efficiently for the removal of Cd from contaminated water

Biallelic Variants in Seven Different Genes Associated with Clinically Suspected Bardet-Biedl Syndrome

Bardet-Biedl syndrome (BBS) is a rare clinically and genetically heterogeneous autosomal recessive multi-systemic disorder with 22 known genes. The primary clinical and diagnostic features include six different hallmarks, such as rod-cone dystrophy, learning difficulties, renal abnormalities, male hypogonadism, post-axial polydactyly, and obesity. Here, we report nine consanguineous families and a non-consanguineous family with several affected individuals presenting typical clinical features of BBS. In the present study, 10 BBS Pakistani families were subjected to whole exome sequencing (WES), which revealed novel/recurrent gene variants, including a homozygous nonsense mutation (c.94C>T; p.Gln32Ter) in the IFT27 (NM_006860.5) gene in family A, a homozygous nonsense mutation (c.160A>T; p.Lys54Ter) in the BBIP1 (NM_001195306.1) gene in family B, a homozygous nonsense variant (c.720C>A; p.Cys240Ter) in the WDPCP (NM_015910.7) in family C, a homozygous nonsense variant (c.505A>T; p.Lys169Ter) in the LZTFL1 (NM_020347.4) in family D, pathogenic homozygous 1 bp deletion (c.775delA; p.Thr259Leufs*21) in the MKKS/BBS5 (NM_170784.3) gene in family E, a pathogenic homozygous missense variant (c.1339G>A; p.Ala447Thr) in BBS1 (NM_024649.4) in families F and G, a pathogenic homozygous donor splice site variant (c.951+1G>A; p?) in BBS1 (NM_024649.4) in family H, a pathogenic bi-allelic nonsense variant in MKKS (NM_170784.3) (c.119C>G; p.Ser40*) in family I, and homozygous pathogenic frameshift variants (c.196delA; p.Arg66Glufs*12) in BBS5 (NM_152384.3) in family J. Our findings extend the mutation and phenotypic spectrum of four different types of ciliopathies causing BBS and also support the importance of these genes in the development of multi-systemic human genetic disorders

Design Optimization and Trade-Offs of Miniaturized Wideband Antenna for Internet of Things Applications

Internet of Things (IoT) will play an important role in modern communication systems. Thousands of devices will talk to each other at the same time. Clearly, smart and efficient hardware will play a vital role in the development of IoT. In this context, the importance of antennas increases due to them being essential parts of communication networks. For IoT applications, a small size with good matching and over a wide frequency range is preferred to ensure reduced size of communication devices. In this paper, we propose a structure and discuss design optimization of a wideband antenna for IoT applications. The antenna consists of a stepped-impedance feed line, a rectangular radiator and a ground plane. The objective is to minimize the antenna footprint by simultaneously adjusting all geometry parameters and to maintain the electrical characteristic of antenna at an acceptable level. The obtained design exhibits dimensions of only 3.7 mm × 11.8 mm and a footprint of 44 mm2, an omnidirectional radiation pattern, and an excellent pattern stability. The proposed antenna can be easily handled within compact communication devices. The simulation results are validated through measurements of the fabricated antenna prototype

Iron III isomaltose induced hypersensitivity reaction

Iron isomaltose is considered as safe form of iron with no test dose recommended. Here, we are describing the case of a patient who experienced allergic reaction with this formulation of iron. A 35-year-old South Asian woman experienced allergic reaction, she had mild wheeze on examination of chest. She was given intranasal oxygen at 2 L/min. She was given intravenous acetaminophen 1 g for pain relief, 45.4 mg intravenous chlorphenaramine and intravenous 100 mg hydrocortisone. Within half an hour, all her symptoms improved and her hypoxia resolved. Her chest wheezing also disappeared. Iron isomaltose, although relatively safe, can cause allergic reaction. Intravenous iron can cause allergic reaction therefore it should be administered at the facility where trained staff is present so that necessary treatment can be given in case of hypersensitivity reaction

Maintaining Quality of Life during the Pandemic: Managing Economic, Social, and Health Well-Being Amid the COVID-19 Crisis of Agricultural Entrepreneurs

Every sphere of life is being impacted by COVID-19, but little is known about how the pandemic is affecting agricultural entrepreneurs’ quality of life in developing nations. Therefore, this study examined how COVID-19 affected agricultural entrepreneurs’ quality of life by utilizing the data collected from 220 females and 1501 males through multistage purposive and random sampling methods. The dataset was analyzed using ordered logistic regression and principal component analysis. The study results indicated that female agricultural entrepreneurs’ quality of life was more adversely affected than that of male agricultural entrepreneurs during COVID-19. The findings also showed that male and female agricultural entrepreneurs with a lower socioeconomic status were more severely impacted than male and female agricultural entrepreneurs with a higher socioeconomic status. More female agricultural entrepreneurs compared to males reported that the pandemic had a negative impact on their mental health. More than two-thirds of both male and female agricultural entrepreneurs reported that the pandemic had a negative impact on their ability to purchase both food and non-food items. Similar to this, a sizable majority of people of both sexes stated that COVID-19 had an impact on their ability to access medical facilities. The results also showed that COVID-19 had a greater impact on married agricultural entrepreneurs’ quality of life than on single people. Therefore, a paradigm shift in agricultural policy is required for the pandemic response to account for COVID-19’s various effects on different genders and socioeconomic groups in rural areas