Terahertz Topological Waveguide and Waveguide based Grating

The upcoming sixth-generation (6G) communication which could emerge as an intelligent platform, is expected to deliver ubiquitous wireless technology. The use of the terahertz (THz) region of the spectrum has the potential to support high data rates (over 100 Gbit/s) and wider bandwidth enabling future 6G wireless technologies and the internet of things. Nevertheless, the THz frequencies have a set of technical challenges including the adequate high power from THz sources and the lack of integrated THz systems with high bandwidth and low cost. The latter can be enabled by a compact planar platform through integrated waveguides and functional components with low loss and low dispersion. Several planar THz waveguides have been proposed for routing THz waves including promising solutions such as metallic parallel-plate waveguides, dielectric two-dimensional photonic crystal waveguides, and hybrid photonic crystal waveguides. Due to THz waveguide interconnection with different components in an integrated THz system, flexibility is required to have the waveguides with bends. However, these current THz waveguides show a lack of robustness and high loss against sharp bends arising from reflection. This results in a narrow transmission bandwidth in the waveguide and waveguides with functional components, i.e., bends, intersections, and junctions. The recent realization of quantum spin Hall photonic topological insulator rises as an avenue to enable robust propagation insensitive to structural impurities and sharp bends through a topological waveguiding solution. Prior topological waveguides are mainly reported either on the microwave or optical frequencies. While we initiate working for topological waveguides in the THz region, since then, a few reports have appeared mostly all-silicon-based topological waveguides. However, these reports present relatively narrow topological single-mode bandwidth due to the high refractive index of silicon. In addition, the need for access to clean rooms and photolithography machines makes the fabrication process expensive. This thesis is structured into two parts: development of THz waveguide and waveguide-based device towards THz integrated system. In the context of a waveguide, this thesis reports low-cost and broad-bandwidth air channel topological integrated waveguide in the THz region which is considered a new field of application stemming from the recent breakthrough in photonic topological insulators. The topological waveguide, composed of hexagonally arranged photonic crystal metallic pillars confined between two metallic parallel plates offers broader relative topological bandwidth beating the previously reported silicon-based THz topologically guided bandwidth with a 60% increase in terms of the actual frequency range. The topological waveguide is fabricated with low-cost 3D printing and a gold sputtering method, for the first time, to the best of our knowledge. The waveguide supports single-mode, linear dispersion, and topological robustness, confirming the low-loss transmission through sharp corners and defects in the measurements. Another crucial point for realizing an integrated THz system is the development of waveguide-based functional devices. The waveguide devices provide the advantage of manipulating THz waves effectively and increase stability compared to free-space isolated optical components. In this development, various waveguide devices are still in demand such as the THz filter, an essential signal-processing device. To realize a passive filter, a common approach is to exploit Bragg grating, a fundamental component, which has been widely demonstrated in the optical range due to low loss silica but less explored in THz due to high absorption losses of polymers. In the context of the waveguide-based device, this thesis reports dual-frequency filtering and dispersion compensating THz waveguide subwavelength grating. The grating is realized using a subwavelength birefringent dielectric core in a cross-section where the periodicity is introduced along the propagation direction. The fabrication of subwavelength waveguide grating is performed using micromachining techniques in a low-loss polymer material, cyclic olefin copolymer. The waveguide grating demonstrates filtering of two orthogonally polarized modes (x- and y- polarizations) with average 8-dB extinction ratios and 5-GHz 3-dB bandwidth for both polarizations. Due to strong index modulation in a subwavelength grating, a large negative group velocity dispersion of -188/ps/mm/THz is achieved which confirms a 7.5 times increase in comparison to the state-of-the-art reported until now in the THz range. In addition, this dispersion is reported in a very compact length of 43 mm which is less than half of the length reported to date, to the best of our knowledge. This thesis shines a light on the development of future integrated THz systems. This is realized by examining the possibility of exploiting a robust waveguide for the short-range broadband THz wireless communication and compact polarization maintaining waveguide-based grating for the THz long-haul wireless/fiber-based links, respectively

En bloc resection of a giant retroperitoneal liposarcoma: A surgical challenge

Liposarcomas are exceedingly rare entities that evoke malignant transformation of connective tissue and fat cells.These tumours occur throughout the soft tissues of the body, afflicting a myriad of regions. In the adult population, liposarcomas represent the most prevalent subtype of sarcomas, and often arise de novo. Retroperitoneal liposarcomas (RLS) are a ubiquitous subset of sarcomas that, due to their deep location in the hollow abdomen, can grow to astronomical proportions before manifesting any noticeable symptoms; a prompt diagnosis of RLS is therefore often rendered dilatory. We hereby delineate the case of a 43-year-old woman who presented with vague left hemiabdominal distention and discomfort. A subsequent computed tomography scan divulged a giant retroperitoneal growth impaling on and thus displacing the pancreas. A compartmental, en bloc resection was performed, with subsequent histopathology of the excised specimen revealing a well-differentiated liposarcoma. The surgical intervention was curative and led to an uneventful recovery. This paper highlights the pertinence of surgical management as an appropriate treatment modality for a complete resection of RLS

EVALUATION OF CYTOTOXIC ACTIVITY OF DICHOLOROMETHANE (DCM) AND METHANOL (MEOH) EXTRACT OF ROOT BARK OF CAPPARIS DECIDUA

The present study was conducted to evaluate the cytotoxic activity of different extracts of root bark of Capparis decidua (Capparidaceae). The root barks of Capparis decidua were collected from village Kirri khaisore Tehsil Pahar pur, Dera Ismail Khan; shade dried and ground into fine powder. The weighed plant material was then extracted with dichloromethane and methanol in triplicate for 72 hours by the process of successive maceration. The filtrate obtained was concentrated under reduced pressure at 30 °C using rotary evaporator. Brine shrimp lethality bioassays and MTT colorimetric assay were carried out on the extracts to assess the cytotoxic activity. Dichloromethane extract showed moderate brine shrimp lethality activity, while this activity was not shown by methanol extract. Both extract showed no cytotoxic activity. Keywords: Capparis decidua, cytotoxicity, Brine Shrim

Pharmacognostic, phytochemical, biological and spectroscopic analyses of Capparis decidua (Forsk.) Edgew root and stem bark

Purpose: To investigate the pharmacognostic, phytochemical, biological and spectroscopic analyses of Capparis decidua (Forsk.) Edgew root and stem bark.Methods: Plant material (root and stem bark) was collected, authenticated, shade-dried and extracted by maceration using methanol as a solvent separately. Powder microscopy was performed using a binocular microscope. Fluorescence, physico-chemical analysis and phytochemical screening for the presence of secondary metabolites were performed using standard methods. Brine shrimp lethalitybioassay was carried out using Artemia salina bioassay, while enzymatic modulatory study was performed by α-amylase inhibition assay. Microscopic analysis was carried out with scanning electron microscopy. Spectroscopic analysis was performed by Fourier transform infrared spectroscopy (FTIR).Results: Powder microscopy showed the presence of different cellular structures. Various colors were observed under ultraviolet (UV) and ordinary light when treated with different reagents. Phytochemical screening revealed the presence of alkaloids, tannins, saponins and flavonoids but phenol and cardiac glycosides were absent from both extracts. The root bark of the plant showed significant brine shrimp lethality activity.Conclusion: Capparis decidua (Forsk.) Edgew root and stem bark contain a variety of bioactive compounds that have medicinal and therapeutic potentials. Therefore, further investigations are required to elucidate their pharmacological properties. Keywords: Capparis decidua (Forsk.) Edgew, Phytochemical, Spectroscopy, α-Amylas

Association between e-cigarette use and myocardial infarction: A systematic review and meta-analysis

Background: The popularity of e-cigarettes has risen dramatically over the last few years, particularly among the younger population. Although the use of combustible cigarettes has established evidence to be associated with the development of several adverse cardiopulmonary diseases, the investigations regarding the prospective long-term effects of e-cigarette use on the cardiovascular system have just begun. We set to investigate if there is an association between the history of MI and e-cigarette use among smokers and non-smokers?Methods: The current review aims to assess the association of myocardial infarction with e-cigarette consumption. PubMed, Google Scholar, and Cochrane Central Register of Controlled Trials (CENTRAL) were queried up to October 2022 to identify articles assessing the incidence of myocardial infarction among e-cigarette users. Data were meta-analyzed using a random-effects model to derive odds ratios (OR) and 95% confidence intervals.Results: Nine studies involving 984,764 patients were included. The mean age of e-cigarette smokers was less than the controls, and female participants dominated the sample size. E-cigarette users were associated with increased odds of MI than non-users [OR = 1.44; 95% CI (1.22, 1.74); P \u3c 0.0001]. Dual users were also associated with increased odds of MI with large effect when compared to non-users [OR = 4.04; 95% CI (3.40, 4.81); P \u3c 0.00001].Conclusions: Dual use is associated with an increased risk of MI than e-cigarette use only. Similarly, dual and solely e-cigarette consumption patterns of nicotine delivery are at a higher risk of MI than non-smokers

Haplotype Analysis for DFNB4/PDS Locus in Hearing Impaired Families of Punjab (Pakistan)

Abstract: Deafness is one of the most common genetic disorders affecting 1 in 1000 newborns worldwide, while in Pakistan, its prevalence is 1.6/1000.The present study was conducted to map reported autosomal recessive deafness locus DFNB4/PDS in highly consanguineous families in Punjab. For this purpose families with deafness were identified . Blood samples of these families were studied for linkage analysis of common reported deafness locus DFNB4/PDS. Genomic DNA was isolated from the blood samples of these families. Linkage analysis was then performed by amplifying microsatellite markers through PCR, Genotyping was done by ABI PRISM ® 3730 Genetic Analyzer. The Deaf Family was found linked to microsatellite markers of DFNB4/PDS. Linkages analysis showed that all three affected were homozygous for three STR markers for DFNB4/PDS while individuals V: 3 was heterozygous i.e., is carrier for DFNB4. Therefore individuals V: 3 were phenotypically normal but genotypically he is carrier. As the ages of that affected individuals' ranges from three years to seven years they might develop goiter at a later age. Therefore at present this family is linked to an overlapping nonsyndromic/ syndromic locus DFNB4/PDS