Dual Band-Notched Microstrip-Fed Vivaldi Antenna Utilizing Compact EBG Structures

We propose an ultra-wideband (UWB) antipodal Vivaldi antenna (AVA) with high-Q stopband characteristics based on compact electromagnetic bandgap (EBG) structures. First, an AVA is designed and optimized to operate over an UWB spectrum. Then, two pairs of EBG cells are introduced along the antenna feed line to suppress the frequency components at 3.6–3.9 and 5.6–5.8 GHz (i.e., WiMAX and ISM bands, resp.). Simulated and measured results show a voltage standing wave ratio (VSWR) below 2 for the entire 3.1–10.6 GHz band with high attenuation at the two selected subbands. This simple yet effective approach eliminates the need to deform the antenna radiators with slots/parasitic elements or comprise multilayer substrates. Furthermore, the flexibility it offers in terms of controlling both the number and locations of the band-reject frequencies is advantageous for antennas with nonuniform flares as in the AVA

Screening Mammograms in Alzheimer’s Disease Patients

Very little guidance exists to help clinicians and families decide whether mammograms are useful in elderly women with Alzheimer’s Disease (AD). We present a case of a patient with moderate AD who had a positive mammogram and discuss the dilemma faced by the family and clinician in deciding what was best to do for the patient. In this case, the family opted for breast conserving surgery (BCS) followed by palliative care which brought up the question of whether screening was appropriate with this treatment goal in mind. We reviewed the literature on AD and breast cancer screening and summarize these findings in our discussion

A Case Control Study of Nutrient Intake Deficiencies in Patients Taking Warfarin

Introduction We previously published the case of a woman taking warfarin who was found to have scurvy, a disease caused by a deficiency of vitamin C. This led us to hypothesize that patients taking warfarin who consume a diet limited in vitamin K rich foods may be at risk for other nutrient deficiencies. To test our hypothesis, we studied dietary nutrient intake in patients taking warfarin compared to patients with heart disease not taking warfarin. Methods The warfarin (n=59) and control groups (n=24) comprised convenience samples of patients with heart disease over age 60 years. Patients completed a three-day food diary and reported use of supplements. Results Based on diet history, the most common deficiencies were vitamin D (100% both groups), vitamin E (93% warfarin, 92% control), vitamin A (71% warfarin, 71% control), vitamin K (66% warfarin, 58% control), vitamin C (58 % warfarin, 46% control) and pantothenic acid (69% warfarin, 71% control) with no significant differences in intake deficiencies between warfarin and control groups. Conclusion All of our patients had nutritional intake deficiencies. This may be due to Appalachian dietary habits and not the low vitamin K diet. It seems prudent to recommend multivitamins, however, universal multivitamin supplementation has not been supported by randomized controlled trials. More study is needed to determine the reason for poor nutritional intake in our Appalachian population and to determine whether similar results are evident in a larger sample

Market dynamics, innovation, and transition in China's solar photovoltaic (PV) industry: a critical review

China's photovoltaic (PV) industry has undergone dramatic development in recent years and is now the global market leader in terms of newly added capacity. However, market diffusion and adoption in China is not ideal. This paper examines the blocking and inducement mechanisms of China's PV industry development from the perspective of technological innovation. By incorporating a Technological Innovation System (TIS) approach, the analysis performed here complements the previous literature, which has not grounded itself in a theoretical framework. In addition, to determine the current market dynamics, we closely examine market concentration trends as well as the vertical and horizontal integration of upstream and downstream actors (74.8% and 36.3%). The results of applying the TIS framework reveal that poor connectivity in networks, unaligned competitive entities and a lack of market supervision obstruct the development of China's PV industry. Therefore, we maintain that inducement mechanisms are required to instigate learning-by-doing capacities, which may help overcome blocking mechanisms and offset functional innovation deficiencies. In addition, policy implications are proposed for promoting the development of the PV industry in China

Using Noun Phrases for Navigating Biomedical Literature on Pubmed: How Many Updates Are We Losing Track of?

Author-supplied citations are a fraction of the related literature for a paper. The “related citations” on PubMed is typically dozens or hundreds of results long, and does not offer hints why these results are related. Using noun phrases derived from the sentences of the paper, we show it is possible to more transparently navigate to PubMed updates through search terms that can associate a paper with its citations. The algorithm to generate these search terms involved automatically extracting noun phrases from the paper using natural language processing tools, and ranking them by the number of occurrences in the paper compared to the number of occurrences on the web. We define search queries having at least one instance of overlap between the author-supplied citations of the paper and the top 20 search results as citation validated (CV). When the overlapping citations were written by same authors as the paper itself, we define it as CV-S and different authors is defined as CV-D. For a systematic sample of 883 papers on PubMed Central, at least one of the search terms for 86% of the papers is CV-D versus 65% for the top 20 PubMed “related citations.” We hypothesize these quantities computed for the 20 million papers on PubMed to differ within 5% of these percentages. Averaged across all 883 papers, 5 search terms are CV-D, and 10 search terms are CV-S, and 6 unique citations validate these searches. Potentially related literature uncovered by citation-validated searches (either CV-S or CV-D) are on the order of ten per paper – many more if the remaining searches that are not citation-validated are taken into account. The significance and relationship of each search result to the paper can only be vetted and explained by a researcher with knowledge of or interest in that paper

Novel microwell-based spectrophotometric assay for determination of atorvastatin calcium in its pharmaceutical formulations

The formation of a colored charge-transfer (CT) complex between atorvastatin calcium (ATR-Ca) as a n-electron donor and 2, 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a π-electron acceptor was investigated, for the first time. The spectral characteristics of the CT complex have been described, and the reaction mechanism has been proved by computational molecular modeling. The reaction was employed in the development of a novel microwell-based spectrophotometric assay for determination of ATR-Ca in its pharmaceutical formulations. The proposed assay was carried out in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm by microwell-plate absorbance reader. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient (0.9995) was found between the absorbance and the concentration of ATR-Ca in the range of 10-150 μg/well. The limits of detection and quantitation were 5.3 and 15.8 μg/well, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from the drugs that are co-formulated with ATR-Ca in its combined formulations. The assay was successfully applied to the analysis of ATR-Ca in its pharmaceutical dosage forms with good accuracy and precision. The assay described herein has great practical value in the routine analysis of ATR-Ca in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and reduction in the analysis cost by 50-fold. Although the proposed assay was validated for ATR-Ca, however, the same methodology could be used for any electron-donating analyte for which a CT reaction can be performed

Combination therapy in hypertension: An update

Meticulous control of blood pressure is required in patients with hypertension to produce the maximum reduction in clinical cardiovascular end points, especially in patients with comorbidities like diabetes mellitus where more aggressive blood pressure lowering might be beneficial. Recent clinical trials suggest that the approach of using monotherapy for the control of hypertension is not likely to be successful in most patients. Combination therapy may be theoretically favored by the fact that multiple factors contribute to hypertension, and achieving control of blood pressure with single agent acting through one particular mechanism may not be possible. Regimens can either be fixed dose combinations or drugs added sequentially one after other. Combining the drugs makes them available in a convenient dosing format, lower the dose of individual component, thus, reducing the side effects and improving compliance. Classes of antihypertensive agents which have been commonly used are angiotensin receptor blockers, thiazide diuretics, beta and alpha blockers, calcium antagonists and angiotensin-converting enzyme inhibitors. Thiazide diuretics and calcium channel blockers are effective, as well as combinations that include renin-angiotensin-aldosterone system blockers, in reducing BP. The majority of currently available fixed-dose combinations are diuretic-based. Combinations may be individualized according to the presence of comorbidities like diabetes mellitus, chronic renal failure, heart failure, thyroid disorders and for special population groups like elderly and pregnant females