Search

The advantages of the beam steering technique are the reduction of interference, save power and to maximize connectivity for point to multi points. Antenna gain degradation is a big problem in the beam steering technique. A new antenna structure is formed by combining the concept of mushroom-like EBG structure with the switching diode to produce the radation pattern control. All sides of the patch antenna are surrounded by several cells for EBG structure. In both of the the left and right sides, through a switching pin diode, the ground plane is attached to vias. The band-stop and band-pass properties of the EBG sector can be changed with the help of switching the diode between ON and OFF state, thus yielding the beam steering into that particular sector. At 6 GHz operational frequency, this structure has the ability to steer 40º (from -20º to +20º) while minimal diodes are utilized, directivity of 10 dBi, gain 9.86 dB and the efficiency is 96.5%. This approach is robust to gain degradation and the main lobe gain is approximately constant for all steering angles. [ABSTRACT FROM AUTHOR]

Increased levels of the inflammatory biomarker high-sensitivity C-reactive protein predict cardiovascular events. Pre-Percutaneoues coronary intervention (PCI) plasma hs-CRP concentration has been reported to influence both short and long term outcome after percutaneoues coronary intervention (PCI). Studies have reported association between pre-PCI CRP and PCI induced cardiac myonecrosis evaluated by sensitive marker of myocardial injury. The present study attempts to evaluate the influence of pre-PCI CRP levels, factors related to the procedure and ongoing medications on the event of post-PCI cardiac myonecrosis. This prospective observational study was done in a Tertiary referral hospital (St. James's Hospital, Dublin, Ireland) involving 38 patients with normal pre-procedural serum troponin T (<0.03μg/litre) undergoing elective PCI. Significantly high basal levels of hs-CRP was detectable in >60% patients undergoing elective PCI. This was further increased to >65% after PCI. Median value of hs-CRP before PCI was 3.61 (range 0.21-47.2mg/L). This value increased to 4.58 (range 0.44-39.2mg/L) after PCI (p<0.05). Though there was significant increase in the post-PCI median value (compared to the pre-PCI value) of TnT (0.015 vs. 0.01μg/L; p<0.001) and CKMBM (4.54 vs. 2.40μg/L; p<0.001), no significant correlation was found between pre-PCI hsCRP and post-PCI TnT (spearman correlation coefficient - 0.074; p=NS) as well as post-PCI CKMBM (spearman correlation coefficient - 0.036; p=NS). The changes in the values of TnT & CKMBM showed moderate positive correlation (spearman correlation coefficient - 0.52; p<0.001). Procedural parameters (of balloon dilatation and stent implantation) did not have significant correlation either. No significant influence of age and ongoing medications was found. Increased hs-CRP levels in serum before PCI was not correlated with significant cardiac myonecrosis detected after PCI.

Isolated left atrial (LA) aneurysm is a rare condition, whereas LA aneurysm secondary to other causes is a fairly common condition. A case of large left atrial aneurysm presented with features of heart failure with cardiac arrhythmia and an abnormal cardiac silhouette on chest X-ray. A 14 years old girl presented with palpitation at rest, shortness of breath, productive cough and bilateral leg swelling for last 8 months. There was no history of chest pain, hemoptysis, syncope, prolonged fever, and rheumatic fever. She was mildly anemic, had raised JVP and mild bilateral pedal edema. There was left parasternal heave, soft S1, loud P2 and a pansystolic murmur of grade 3/6 over mitral area radiating to the left axilla. ECG showed multifocal atrial tachycardia (MAT), chest X-ray showed cardiomegaly with bulging of the left heart border with upper lobe diversion. Echo-Doppler study showed hugely dilated LA (115 mm in diameter), dilated left ventricle, Grade-2+ mitral regurgitation (MR), mild tricuspid regurgitation (TR) and mild pulmonary hypertension with normal appearing mitral, aortic and tricuspid and pulmonary valves. The patient was diagnosed as a case of congenital aneurysm of LA.