Continuous Beam Steering Through Broadside Using Asymmetrically Modulated Goubau Line Leaky-Wave Antennas

Goubau line is a single-conductor transmission line, featuring easy integration and low-loss transmission properties. Here, we propose a periodic leaky-wave antenna (LWA) based on planar Goubau transmission line on a thin dielectric substrate. The leaky-wave radiations are generated by introducing periodic modulations along the Goubau line. In this way, the surface wave, which is slow-wave mode supported by the Goubau line, achieves an additional momentum and hence enters the fast-wave region for radiations. By employing the periodic modulations, the proposed Goubau line LWAs are able to continuously steer the main beam from backward to forward within the operational frequency range. However, the LWAs usually suffer from a low radiation efficiency at the broadside direction. To overcome this drawback, we explore both transversally and longitudinally asymmetrical modulations to the Goubau line. Theoretical analysis, numerical simulations and experimental results are given in comparison with the symmetrical LWAs. It is demonstrated that the asymmetrical modulations significantly improve the radiation efficiency of LWAs at the broadside. Furthermore, the measurement results agree well with the numerical ones, which experimentally validates the proposed LWA structures. These novel Goubau line LWAs, experimentally demonstrated and validated at microwave frequencies, show also great potential for millimeter-wave and terahertz systems

Capacitor-Loaded Spoof Surface Plasmon for Flexible Dispersion Control and High-Selectivity Filtering

This letter proposes a new spoof surface plasmon transmission line (SSP-TL) using capacitor loading technique. This new SSP-TL features flexible and reconfigurable dispersion control and highly selective filtering performance without resorting to configuration change. Moreover, it requires much smaller linewidth than the conventional SSP-TL for achieving an extremely slow wave (or a highly confined field), which is quite useful for a compact system. To illustrate the design principle, several examples are designed within the frequency range of 2-8 GHz. Both numerical and experimental results are given in comparison with the conventional SSP-TL. It is demonstrated that the proposed technique provides a better performance in size reduction and dispersion reconfigurability

Discrepancies in Oral Care Standards in Head and Neck Cancer Patients in India

Head and neck cancer patients have a very strict oral care requirement for a good quality of life. To address this a supportive oral care protocol (SOCP) was developed by us and validated with cancer care experts throughout the country. Oral supportive care is Standard of care for head and neck cancer patients, which is lacking in our country. Radiation caries, trismus, mucositis osteoradiaonecrosis, xerostomia and need for oral maxillofacial prosthesis are known side effect of cancer therapies. All this can be easily managed and minimized by providing optimal care as an integral part of cancer care. These health related disparities due to nonintergration of cancer care with oral care results in poor quality of life. We here present a case series of 10 patients with squamous cell carcinoma of oral and head and neck region enrolled at our center and their preventive and definitive management using our SOCP

To evaluate the antigingivitis and antipalque effect of an Azadirachta indica (neem) mouthrinse on plaque induced gingivitis: A double-blind, randomized, controlled trial

Background: Azadirachta indica (neem), a Meliaceae family tree, has been used in India for several decades for the treatment of several diseases in medicine and dentistry. Neem has been considered to have antiseptic activity, but still its use for the treatment of gingivitis and periodontitis is not very clear. Hence, the purpose of the present study was to assess the efficacy of neem based mouth rinse regarding its antigingivitis effect. Materials and Methods: Forty five subjects with plaque induced gingivitis were selected for the study. They were equally divided into three groups. Group I patients were asked to rinse with 15 ml of neem mouthwash twice daily, group II with 15 ml of chlorhexidine mouthwash twice daily, and group III with 15 ml of saline twice daily. The three groups were asked to perform the routine oral hygiene procedures thought out the study period. Bleeding on probing and gingivitis were evaluated by Muhlemann and Son′s Sulcus bleeding index (1971) and Loe and Sillness gingival index (1963), respectively, at base line, after every week till one month. Results: Our result showed that an A. indica mouthrinse is equally effective in reducing periodontal indices as Chlorhexidine. The results demonstrated a significant reduction of gingival, bleeding, and plaque indices in both groups over a period of 21 days as compared to placebo. Conclusion: A. indica-based mouth rinse is equally efficacious with fewer side effects as compared to chlorhexidine and may be used as an adjunct therapy in treating plaque induced gingivitis

Evaluation of platelet-rich plasma alone or in combination with demineralized freeze dried bone allograft in treatment of periodontal infrabony defects: A comparative clinical trial

Aims: The use of platelet-rich plasma (PRP) alone in periodontal defects has been controversial and inconclusive. Hence, the present study was designed with the aim to assess the clinical and radiographic effectiveness of PRP alone in infrabony defects. Materials and Methods: Thirty infrabony defects were treated with either autologous PRP with open flap debridement (OFD) or autologous PRP + demineralized freeze dried bone graft (DFDBA) with OFD or OFD alone. Clinical parameters recorded were gingival index, plaque index, probing depth (PD), clinical attachment level (CAL), and gingival recession (REC). Radiographic parameters included defect depth reduction, defect resolution, and crestal bone level. All the parameters were recorded at baseline and 12 months postoperatively. Results: Mean PD reduction and CAL gain were greater in PRP + DFDBA (4.88 ± 1.12 mm and 4.26 ± 1.85 mm) and PRP (4.86 ± 2.12 mm and 4.10 ± 1.47 mm) groups than the control group (2.69 ± 1.37 mm and 1.27 ± 0.89 mm). Conclusions: Within the limits of the study, all the three groups showed significant improvement in clinical parameters from baseline to postoperative 12 months. The amount of defect depth reduction and defect resolution treated with PRP alone group were significantly < PRP + DFDBA. The results pertaining to these parameters were significantly better than the control group

Realization of Low Profile Leaky Wave Antennas Using the Bending Technique for Frequency Scanning and Sensor Applications

This paper proposes an efficient transmission line modulation by using the bending technique to realize low profile leaky wave antennas in the Ku-band for frequency scanning and sensor applications. The paper focuses mainly on the bending effects of the transmission line in terms of the sharpness of edges. The right-hand/left-hand transmission line can be designed in the form of zig-zag pattern with sharp corners and only the right-hand transmission line in the form of sinusoidal patterns with smooth corners. In this presentation, we demonstrate that transmission lines of this kind can be used to realize highly efficient leaky wave antennas with broadband impedance matching and high gain characteristics in the Ku-band. Dispersion analysis and ladder network analysis have been performed for investigating the performance of the proposed designs. The sharpness of the bends periodically distributed along the body of the antenna has been used to our advantage for frequency scanning in the left-hand and right-hand quadrants at different frequencies. The proposed bending technique has been proven to be instrumental in achieving the desired characteristics of low profile leaky wave antennas