A Comprehensive Review of In-Body Biomedical Antennas: Design, Challenges and Applications.

In-body biomedical devices (IBBDs) are receiving significant attention in the discovery of solutions to complex medical conditions. Biomedical devices, which can be ingested, injected or implanted in the human body, have made it viable to screen the physiological signs of a patient wirelessly, without regular hospital appointments and routine check-ups, where the antenna is a mandatory element for transferring bio-data from the IBBDs to the external world. However, the design of an in-body antenna is challenging due to the dispersion of the dielectric constant of the tissues and unpredictability of the organ structures of the human body, which can absorb most of the antenna radiation. Therefore, various factors must be considered for an in-body antenna, such as miniaturization, link budget, patient safety, biocompatibility, low power consumption and the ability to work effectively within acceptable medical frequency bands. This paper presents a comprehensive overview of the major facets associated with the design and challenges of in-body antennas. The review comprises surveying the design specifications and implementation methodology, simulation software and testing of in-body biomedical antennas. This work aims to summarize the recent in-body antenna innovations for biomedical applications and indicates the key research challenges.

Switchable edge-line coupler based on parity time-reversal duality symmetry.

A compact broadband Edge-Line Coupler (ELC) based on Parity Time-reversal Duality (PTD) symmetry has been conceived, designed, constructed and measured. The coupler connects four PTD bifilar edge lines (BELs), recently introduced by the authors. The PTD-BELs are constituted by a parallel plate waveguide whose walls are formed by a junction between Perfect Electric Conductor (PEC) and Perfect Magnetic Conductor (PMC) boundary conditions. Reversing the axis orthogonal to the plates interchanges the position of PEC and PMC. Such a waveguide supports unimodal transverse electromagnetic (TEM) propagation, extremely confined along the top and bottom junction edges; its propagation is protected against backscattering from any discontinuity that preserves the PTD symmetry. The ELC presented here is constituted by a 4-port junction in which each port is intrinsically matched due to the PTD symmetry, strongly coupled with a second port, strongly decoupled with a third port, and weakly coupled with a fourth port. The ELC is designed by using a mushroom metasurface for the PMC portion of the device; the connection is based on a switch circuit which imposes open and short conditions on the two opposite sides of the structure. Switching simultaneously the open and short circuits reroutes the signal in a different port, while maintaining the same level of coupling with the other ports. A static prototype has been built and its measurements have confirmed the matching performance and the good directionality of the coupler in a broadband frequency range between 24 and 30 GHz.

The Use of Intracranial Vessel Wall Magnetic Resonance Imaging to Detect a Presumptive Syphilitic Brain Aneurysm.

ABSTRACT: Syphilitic intracranial aneurysm is a rare presentation of meningovascular syphilis in developed countries. In this case report, we discuss the utilization of the intracranial vessel wall magnetic resonance imaging in the management of a patient with a rare fusiform brain aneurysm, positive syphilis serologies, and inconclusive cerebrospinal fluid findings.

Development and validation of an economical uric acid-Fe3+/Fe2+-ferrozine-based colorimetric assay to estimate uric acid level of pure and biological samples.

This work presents the development and validation of a simple, rapid, and cost-effective spectrophotometric method for quantitative analysis of uric acid in biological samples. The method relies upon uric acid-led reduction of Fe(III) to Fe(II) of sample/standard solutions which stoichiometrically engages ferrozine to form a magenta-colored complex. Different parameters including pH, metal and chelator concentrations, temperature, etc., were optimized for the maximum intensity and stability of the complex. The uric acid concentrations of synthetic/plasma solutions were determined by comparing the color intensity of Fe(ferrozine)3 2+ complex produced by test solution with the standard curve formed by known uric acid concentrations. The method was validated in accordance with ICH guidelines and subjected to human plasma analysis. The results obtained were compared with a reference (enzymatic) method which revealed that there was no significant difference between the two methods at 95% confidence level. The method is highly specific, precise, linear, accurate, and robust.

Recurrent urinary tract infections caused by Raoultella planticola after kidney transplant.

Recurrent urinary tract infections are difficult to manage in patients with a history of kidney transplant and may contribute to graft loss. Few cases describe recurrent urinary tract infections due to Raoultella planticola in this population. We describe the management of recurrent urinary tract infections due to R planticola in a kidney transplant recipient and review other case reports of urinary tract infections due to this organism.

Expression deregulation of DNA repair pathway genes in gastric cancer.

This study was designed to check correlation of mRNA and protein expression of BER pathway genes(XRCC1, OGG1) and a proliferation marker (Ki-67) in 100 gastric tissue samples and controls (adjacent uninvolved area). The expression was estimated usingreal time PCR and immunohistochemistry. Genomic instability was also calculated in the same study cohort using 8-OHdG assay, DNA fragmentation assay and comet assay. A significant downregulation of XRCC1 (p < 0.0001) and OGG1 (p < 0.0001) expression was observed in gastric cancer tumors vs controls. When analyzed with spearman correlation, significant positive correlation was observed between OGG1 vs XRCC1 (r = 0.319*, p < 0.02) and significant negative correlation was observed between OGG1 vs Ki-67 (r = -0.462**, p < 0.001) and XRCC1 vs Ki-67 (r = -0.589**, p < 0.001) in gastric cancer tumors. Significantly higher level of 8-OHdG, when compared to controls, was observed in gastric cancer tumors (p < 0.0001). DNA fragmentation assay and comet assay showed the formation of increased ladder patterns and comets in gastric cancer tumors when compared with controls These findings suggest that dysregulation of XRCC1, OGG1 combined with overexpression of Ki-67 may contribute to progression of gastric cancer and may help to sub-classify patients within diverse risk groups for therapeutic advantages.

Scedosporiosis in a Combined Kidney and Liver Transplant Recipient: A Case Report of Possible Transmission from a Near-Drowning Donor.

Scedosporium spp. are saprobic fungi that cause serious infections in immunocompromised hosts and in near-drowning victims. Solid organ transplant recipients are at increased risk of scedosporiosis as they require aggressive immunosuppression to prevent allograft rejection. We present a case of disseminated Scedosporium apiospermum infection occurring in the recipient of a combined kidney and liver transplantation whose organs were donated by a near-drowning victim and review the literature of scedosporiosis in solid organ transplantation.

Phytochemical and in vitro total antioxidant capacity analyses of peel extracts of different cultivars of Cucumis melo and Citrullus lanatus.

CONTEXT: Cucumis melo Linn. (Cucurbitaceae) and Citrullus lanatus Thunb. (Cucurbitaceae) are desert vegetables popular for their nutritional value and year round availability. The pulp and seeds of these plants are used for dietary purposes or as medications for certain ailments in the folk medicinal system. Peels of the fruit are either wasted or used as feed of grazing animals. OBJECTIVE: A detailed investigation regarding the chemical constituents and antioxidative analyses of the peel extract of fully ripened fruits from different cultivars of the two vegetables was carried out here for the first time. MATERIALS AND METHODS: Chemical constituents of the peel extracts of C. melo and C. lanatus cultivars in methanol, 1-butanol, chloroform and n-hexane were analysed by gas chromatography-mass spectrometry (GC-MS) and the antioxidative properties were evaluated using standard in vitro antioxidative assays. RESULTS: The results demonstrated large variation in the chemical constituents of the extracts including alkanes, saturated and unsaturated fatty acids and their esters, cyclic ketones, aldehydes, phenolic compounds and anthocyanin derivatives. Total phenolic content ranged from 2.96-0.85 mg/L gallic acid equivalents for different extracts. DISCUSSION AND CONCLUSION: Employing GC-MS analyses and standard in vitro antioxidative assays, the data presented here clearly demonstrate the potency of C. melo and C. lanatus extracts as antioxidant and radical scavenger plants which may be used as good sources of natural antioxidants. The peels of both the plants can be added to the diet at various stages to compensate food shortage and dietary deficiency problems of living beings.

Posttransplantation lymphoproliferative disorder with skin involvement.

Posttransplantation lymphoproliferative disorders (PTLD) are lymphoid proliferations or lymphomas that develop as a result of immunosuppression in recipients of solid organs and bone marrow allografts. The disorder is seen in 1-2% of renal transplant recipients with a variable time period of presentation and is usually seen within the first year following transplantation. We report a case of B-cell lymphoma (PTLD WHO class-3) presenting with skin involvement in a patient of renal transplantation, 8 years after receiving the transplant.