Planar Dual-Band Monopole Antenna with an Extended Ground Plane for WLAN Applications

A compact planar microstrip-fed monopole antenna designed for dual-band operation is proposed for WLAN applications. The antenna is composed of a rectangular strip monopole in addition to an inverted-L parasitic element that is connected to the truncated ground plane of the microstrip feed. Besides exciting an additional band of operation, the parasitic element also improves the bandwidth of the band excited by the strip monopole. Several simulated parametric studies are conducted to investigate the effects of each geometrical parameter on the behavior of the antenna. Experimental and simulation results demonstrate that the proposed antenna covers the 2.4 and 5.8 GHz bands utilized in WLAN. In both bands, the proposed antenna exhibits good impedance match, moderate gain (approximately 2 dBi), and sustainable omnidirectional-like radiation patterns in both principal planes. An equivalent circuit model of the antenna is also developed

A Novel Three-Dimensional Beamforming Antenna Array for Wireless Power Focusing

An antenna array capable of focusing the power transmitted to a specified point in space is modeled and simulated. This array will serve best for wireless power transmission applications where one of the goals is to maximize the power transfer efficiency. The array consists of 100 dipole antennas with each antenna transmitting a sum of 50 signals where each signal has a different frequency. This difference in frequency gives an additional degree of freedom that allows the overall beam pattern to be focused to a point in space instead of just a direction. The same array structure is also capable of transmitting power to multiple points in space which is promising when it comes to powering multiple points of interest

Diminishing benefits of urban living for children and adolescents’ growth and development

A list of authors and their affiliations appears online.Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified.peer-reviewe

Subacute thyroiditis following influenza vaccine: a case report and literature review

Subacute thyroiditis following influenza vaccination is a rarely reported condition. Here, we review this condition and report the case of a 40-year-old male who developed subacute thyroiditis following the administration of an influenza vaccine containing the (H1N1) pandemic 2009 strain. Interestingly, the patient had history of pericarditis and his HLA typing showed HLA B35. Physicians should be aware of this complication for influenza vaccine and of the relationship of HLA B35 haplotype with the susceptibility to subacute thyroiditis and other autoimmune disorders

Esophageal 99mTc-pertechnetate uptake mimicking an autonomous thyroid adenoma in a patient with subacute thyroiditis: a case report

Subacute thyroiditis (SAT) is one of the most common causes of thyrotoxicosis. Thyroid scans with radioiodine or technetium-99m pertechnetate (99mTc) are often performed in the workup of patients with thyrotoxicosis, particularly to differentiate between SAT and Graves’s disease. Although very helpful, thyroid scans are prone to pitfalls that may occasionally lead to misdiagnosis. These pitfalls are largely related to physiologic uptake of radioiodine or 99mTc in non-thyroidal tissue, such as salivary gland and stomach that may result in false-positive findings. We present herein a very rare case of SAT misdiagnosed as an autonomous thyroid adenoma most likely due to focal 99mTc uptake in the esophagus. This case may have implications for the management of patients with suspected SAT, who undergo a radioiodine or 99mTc thyroid scan

Smokers′ hair: Does smoking cause premature hair graying?

Aims: To determine if there is a significant association between premature hair graying and cigarette smoking. Materials and Methods: A cross-sectional observational study was conducted in a nonclinical setting on 207 participants on August 24 until 25, 2010. Participants were classified into two groups [premature hair graying (PHG) and normal hair graying]. PHG was defined as the first appearance of gray hair before the age of 30. Data were collected using an interview questionnaire and measurements of body mass index, waist circumference, fasting blood glucose and blood pressure. Collected data were statistically analyzed using SPSS 16, Chicago, IL. Results: Of the 207 subjects, 104 (50.2%) had first appearance of gray hair before the age of 30 (PHG group) while the other 103 (49.8%) were considered normal hair graying group. The prevalence of smokers in the "PHG" group was higher (40.2% vs. 24.7%, P = 0.031). Smokers had earlier onset of hair graying (smokers: 31 (7.4) vs. nonsmokers: 34 (8.6), P = 0.034). Using multiple logistic regression with conditional likelihood, smokers were two and half times (95% CI: 1.5-4.6) more prone to develop PHG. Conclusion: This study suggests that there is a significant relation (with adjusted odds ratio of two and half) between onset of gray hair before the age of 30 and cigarette smoking

Fabrication of Hybrid Materials Based on Waste Polyethylene/Porous Activated Metakaolinite Nanocomposite as an Efficient Membrane for Heavy Metal Desalination Processes

Hybrid nanostructure materials derived from activated metakaolinite are of growing importance due to their intriguing structural/functional properties and promising biomedical/environmental applications, especially designing desalination membranes. Herein, we report procedures to design and fabricate membranes based on waste polyethylene/porous activated-metakaolinite thin film nanocomposites (WPE/PAMK-TFN). It has been devoted to improving water desalination processes, where efficient removal of trace level (~250 ppm) of toxic heavy metals such as Cd(II), Pb(II), and Cu(II) ions from synthetic wastewater solutions was highly accomplished. Physicochemical techniques such as X-ray diffraction (XRD), surface analysis (BET), and Fourier transform infrared spectroscopy (FTIR) have been extensively employed to elucidate the structure/composition of the prepared nanomaterials. The effect of concentration (0–0.5 wt%) of porous activated-metakaolinite (PAMK) on water permeation was investigated. The results obtained revealed that 0.5 wt% of PAMK clay particles produced the highest dispersion, as evident by SEM images of the nanocomposite membranes. Significantly, the constructed membrane showed marked improvements in porosity, hydrophilicity, and hydraulic resistance. Moreover, elemental mapping studies have confirmed the intercalation of activated bentonite clay within the polymer matrix. The obtained results demonstrated that increased flux and rejection capability of membranes occurred at high clay dosage. In contrast, the low rejection capability was observed at either lower pH and higher initial feed concentrations. Ultimately, for 250 ppm of Cd(II), Pb(II), and Cu(II) ions, the constructed membranes showed maximum removal capability of 69.3%, 76.2%, and 82.5% of toxic cations, respectively

Predetermined Anti-Diabetic Drug Regimen Adjustments during Ramadan Fasting: An Observational Study of Safety

BackgroundMany Muslim type 2 diabetes mellitus (T2DM) patients choose to fast the month of Ramadan despite the possible adverse health effects brought about by the change in dietary habits, among other things. Clinical data regarding the safety of multi-drug regimens during fasting are particularly scarce. The aim of the study was to evaluate the safety of a drug protocol devised by the authors to accommodate Ramadan's dietary changes, involving dose adjustments of four anti-diabetic drug regimens in T2DM patients fasting Ramadan.MethodsIn this prospective, observational, open-label study, 301 T2DM patients who wished to fast Ramadan were followed during Ramadan and the preceding month. The incidence of hypoglycemia, diabetic ketoacidosis (DKA) and non-ketotic hyperosmolar state (NKHS) was monitored. Patients were classified into four groups: A group (those taking metformin, sulfonylurea and insulin [n=33]); B group (metformin and sulfonylurea [n=89]); C group (metformin and insulin [n=96]); and D group (premixed 70/30, glargine or regular insulin [n=82]). During Ramadan, drug doses were adjusted as percentages of their pre-Ramadan values: 75% for sulfonylureas, 75% for glargine, 75% for premixed insulin 70/30 in two doses, and 75% for regular insulin. Metformin was adjusted to a twice-daily regimen.ResultsNo cases of DKA or NKHS were reported. Hypoglycemia occurred at a lower rate than pre-Ramadan values in groups C, and D; and a similar rate in groups A, and B.ConclusionThe data suggested that using the above protocol to adjust the doses of anti-diabetic drugs is safe in T2DM patients in regards to hypoglycemia, DKA, and NKHS