A Study on Application of Dielectric Resonator Antenna in Implantable Medical Devices

Worldwide, a large number of patients are benefited every year due to technological advancement in implantable medical devices (IMDs) such as in hyperthermia and bio-telemetry. The combination of sensors and antennas defined the quality of the implantable device. Antenna communities strive hard to fulfill the needs of the medical world by introducing new designs and concepts in this field. The purpose of this study is to identify major existing challenges and provide suitable solution of these challenges for implant applications. Present implant antennas have faced inferior performance due to high metallic losses and varied implant depth. The human body is a combination of dielectric materials, regardless of whether it is liquid (eg. water), gels or hard bones. In this study, first time a dielectric resonator antenna (DRA) resonating at 2.45 GHz, has been proposed as an implantable antenna with no metallic losses, varied implant depth performance and bio-compatibility. The implant DRA is placed on a bio-compatible polyvinyl chloride (PVC) substrate with a thickness of 0.5 mm. The rectangular DRA excited by a coplanar waveguide feed is proposed and its performance is compared with the help of four phantoms given in the literature. A detailed link design study was also undertaken in view of the different applications

MALDI-TOF mass spectrometry: an emerging technology for microbial identification and diagnosis

Currently microorganisms are best identified using 16S rRNA and 18S rRNA gene sequencing. However, in recent years Matrix Assisted Laser Desorption Ionization-Time of Flight mass spectrometry (MALDI-TOF MS) has emerged as a potential tool for microbial identification and diagnosis. During the MALDI-TOF MS process, microbes are identified using either intact cells or cell extracts. The process is rapid, sensitive and economical in terms of both labor and costs involved. The technology has been readily imbibed by microbiologists who have reported usage of MALDI-TOF MS for a number of purposes like, microbial identification and strain typing, epidemiological studies, detection of biological warfare agents, detection of water- and food-borne pathogens, detection of antibiotic resistance and detection of blood and urinary tract pathogens etc. The limitation of the technology is that identification of new isolates is possible only if the spectral database contains peptide mass fingerprints of the type strains of specific genera/species/subspecies/strains. This review provides an overview of the status and recent applications of mass spectrometry for microbial identification. It also explores the usefulness of this exciting new technology for diagnosis of diseases caused by bacteria, viruses and fungi

Multiple input multiple output dielectric resonator antenna with circular polarized adaptability for 5G applications

In this paper, the concept of the circularly polarized agile, multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) structure for fifth generation (5G) new radio application in mobile terminal is presented. Two prototypes have been fabricated, namely one with cylindrical DRA (CDRA) referred as A1 and a second one with ring DRA (RDRA) named as A2. These practical realizations of dual-port MIMO antennas have been mounted on a Rogers 5870 substrate of octagonal shape with proper ground architecture. The proposed dual-port MIMO antennas have been excited with conformal probes and L-type feed network aiming to achieve circular polarization (CP). Measured impedance bandwidth of A1 and A2 are 21.2% (3.15-3.9 GHz) and 22.2% (3.12-3.9 GHz), respectively. Moreover, for both antennas low mutual coupling between ports with minimum isolation of dB over entire impedance bandwidth has been obtained by using triangular head slots in the ground plane. Measured axial ratio bandwidths in broadside direction are 5.66% (3.26-3.45 GHz) and 4.25% (3.45-3.6 GHz), respectively. Maximum gains are 7.3 and 7.2 dBi, in that order. MIMO antenna parameters such as envelope correction coefficient, diversity gain (DG), mean effective gain and total active reflection coefficient are also calculated to verify MIMO performance parameters. The proposed antennas also demonstrate CP agility with insertion of concentric cylindrical shells of different radii

Dual-band circularly polarized MIMO DRA for sub-6 GHz applications

In this article, a dual-band circularly polarized multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is proposed for 3.5 and 5.5 GHz bands, both being located under 6 GHz. Known as sub-6 (or as mid-band), they provide good coverage and capacity in the newly targeted fifth-generation (5G) systems. The proposed structure consists of two ring DRAs (RDRAs) etched on a 0.8 mm thick RT Duroid substrate. Measured impedance bandwidths in broadside direction are 3.1-3.75 GHz (19%) and 5.3-5.6 GHz (9.4%) and circular polarization (CP) bandwidths are 3.425-3.6 GHz (5%) and 5.45-5.55 GHz (2%), respectively. CP is achieved by exciting HE modes using two probes placed orthogonaly to each other, that is, at an azimuthal angular distance of 90∘. Varying the lengths of the probe allows achieving the necessary time-phase quadrature between modes. Comparison between recent multiband circularly polarized MIMO DRAs and proposed prototype has revealed that CP bandwidth in both bands is one of the highlighting advantages of the present configuration

Dielectric Resonator Antennas: Applications and developments in multiple-input, multiple-output technology

This article presents a comprehensive review of multiple-input, multiple-output (MIMO) dielectric resonator antennas (DRAs) that have evolved in the past decade. In addition to the major challenges faced during designing an MIMO DRA, this article also discusses research gaps that must be filled in the future. Exploring the advantages of DRAs, numerous novel designs have been proposed in the last few years

Comparative larval biology of three Macrobrachium species under controlled conditions

Three large sized Macrobrachium species-. viz. Macrobrachium rosenbergi;, M malcolmsonii and M gangelicum are available in Indian riverine systems. The study on the seed production and growout of these species are being carried out to develop technologies for commercial application. Hence, the knowledge on comparative larval biology of the three species is extremely important to give a new line for developing hatchery technology for large-scale seed production in different agro-climatic conditions. The present communication deals with comparative study of larval growth and seed production of the three larger species

Different mechanisms of inflammation induced in virus and autoimmune-mediated models of multiple sclerosis in C57BL6 mice.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the human central nervous system (CNS). Neurotropic demyelinating strain of MHV (MHV-A59 or its isogenic recombinant strain RSA59) induces MS-like disease in mice mediated by microglia, along with a small population of T cells. The mechanism of demyelination is at least in part due to microglia-mediated myelin stripping, with some direct axonal injury. Immunization with myelin oligodendrocyte glycoprotein (MOG) induces experimental autoimmune encephalomyelitis (EAE), a mainly CD4(+) T-cell-mediated disease, although CD8(+) T cells may play a significant role in demyelination. It is possible that both autoimmune and nonimmune mechanisms such as direct viral toxicity may induce MS. Our study directly compares CNS pathology in autoimmune and viral-induced MS models. Mice with viral-induced and EAE demyelinating diseases demonstrated similar patterns and distributions of demyelination that accumulated over the course of the disease. However, significant differences in acute inflammation were noted. Inflammation was restricted mainly to white matter at all times in EAE, whereas inflammation initially largely involved gray matter in acute MHV-induced disease and then is subsequently localized only in white matter in the chronic disease phase. The presence of dual mechanisms of demyelination may be responsible for the failure of immunosuppression to promote long-term remission in many MS patients

Effect of pre- and post-harvest treatments on yield, quality and post-harvest shelf life of king chilli (Capsicum chinense Jacquin) under foothill conditions of Nagaland (India)

Field and laboratory experiments were carried out at Medziphema (Nagaland) to evaluate the effect of pre- and post-harvest treatments on yield, quality and post-harvest life of King chilli (Capsicum chinense Jacquin) under foothill conditions of Nagaland. Highest fresh yield (13.65 t ha-1) and capsaicin content (819421.13 SHU) of fruits were recorded with application of Naphthalene Acetic Acid (40 ppm). Maximum vitamin C content (115.67 mg 100g-1 of fruit) was recorded with application of Ethrel 250 ppm. Lowest physiological loss in weight (2.55%) and change in fruit colour (10%), highest value of ascorbic acid content (120.5 mg 100 g-1 of fruit) and longest shelflife (9 days) were recorded at 9th day after storage in calcium chloride (0.5%) treated fruits, packed in non-perforated bags and stored under refrigeration at 5oC. &nbsp

Effect of pre- and post-harvest treatments on yield, quality and post-harvest shelf life of king chilli (Capsicum chinense Jacquin) under foothill conditions of Nagaland (India)

Field and laboratory experiments were carried out at Medziphema (Nagaland) to evaluate the effect of pre- and post-harvest treatments on yield, quality and post-harvest life of King chilli (Capsicum chinense Jacquin) under foothill conditions of Nagaland. Highest fresh yield (13.65 t ha-1) and capsaicin content (819421.13 SHU) of fruits were recorded with application of Naphthalene Acetic Acid (40 ppm). Maximum vitamin C content (115.67 mg 100g-1 of fruit) was recorded with application of Ethrel 250 ppm. Lowest physiological loss in weight (2.55%) and change in fruit colour (10%), highest value of ascorbic acid content (120.5 mg 100 g-1 of fruit) and longest shelflife (9 days) were recorded at 9th day after storage in calcium chloride (0.5%) treated fruits, packed in non-perforated bags and stored under refrigeration at 5oC. &nbsp