Metal- and Dielectric-Loaded Waveguide: An Artificial Material for Tailoring the Waveguide Propagation Characteristics

In the present chapter a number of loaded structures are studied with circular cross-section to explore the deviation in their dispersion characteristics from their parent circular waveguide. The dielectric and/or metal loading to the waveguide tailors its dispersion characteristics. In general, the dielectric depresses and the metal elevates the dispersion characteristics from the characteristics of their parent circular waveguide. The axial periodicity results in periodic dispersion characteristics with a lower and an upper cut-off frequency (bandpass). However such a characteristic is not reported for the azimuthal periodic structures. The bandpass characteristic arises due to the shaping of the dispersion characteristics. Therefore the dispersion shaping is only possible with axial periodicity and not with the azimuthal periodicity. The sensitivity of the structure (geometry) parameters on the lower and upper cut-off frequencies, the extent of passband and the dispersion shaping are also included. In the axial periodic structures, the periodicity is found to be the most sensitive parameter for tailoring the dispersion characteristics and the disc-hole radius is the most sensitive parameter for shifting the dispersion characteristics over the frequency axis

Factors affecting transduction efficiency of pseudotyped viral vectors incorporating alphaviral glycoproteins

The genome of an organism has the complete set of biochemical instructions required for sustenance of life. Mutations or abnormalities in this genome lead to genetic disorders. Currently available therapeutic options mostly focus on treating the symptoms, but not curing them. Gene therapy promises to be a curative form of medicine. In gene therapy cells carrying a defective gene are targeted and replaced with a healthy copy of that gene. The vehicles used for delivering this gene are known as vectors. Retroviruses are popularly used gene therapy/transfer vectors. However, retroviruses are limited in the range of cells they can enter and infect. The range of cells targeted by the viral vector can be either expanded or narrowed by replacing the envelope of the virus with the envelope of another virus that has the desired range of tissue tropism. Such hybrid viruses are called pseudotyped viruses. Previously, we have pseudotyped Moloney Murine Leukemia Virus (MoMuLV), a retrovirus with the envelope of Ross River Virus (RRV), an alphavirus. Here, we substituted amino-acid residues of RR-envelope glycoprotein with basic amino-acid residues. We show that this makes the pseudotyped virus utilize heparan sulfate, a ubiquitous molecule present on the surfaces of most cells, as an attachment factor. Attachment to cellular heparan sulfate helps in concentration of virus particles on the cell surface and thus enhancing their chances of cell entry, thereby increasing their transduction efficiency of this viral vector. The same affinity towards heparan sulfate, however, poses a challenge in terms of release of this pseudotyped virus from the producer cells. General principles concerning viral adaptation to the use of attachment factors and improving pseudotyped virus titers through modifying cell membrane components can be derived from these results. We also show that alphavirus-glycoprotein retroviral pseudotypes require cholesterol for entry into the cells. Furthermore, excess cholesterol in cells facilitates the entry of alphavirus-glycoprotein retroviral pseudotypes. We show that alphavirus-glycoprotein pseudotypes transduce the acid sphingomyelinase deficient (ASMase-/-) cells derived from Niemann Pick’s disease-model mice more efficiently than the cells from healthy mice (ASMase+/+). Thus alphavirus-glycoprotein pseudotypes hold a potential as suitable vectors for gene therapy/ transfer in Niemann Pick’s Disease-Type A, a genetic lipid-storage disorder

Tobacco Use and its Dental Implications: A Review

Use of tobacco can be attributed to oral diseases and disorders like oral cancer, periodontal disease, caries and gingival recession along with various other benign mucosal disorders as well as failure of implants. The need for specific attention is given to the impact of tobacco cessation on oral health outcomes. This review concluded that severe robust epidemiologic evidence exists for the adverse oral health effects of tobacco smoking and other types of tobacco use

A Qualitative Analysis of Healthcare Students’ Perceptions Towards Online Learning due to the COVID-19 Pandemic

INTRODUCTION: While online learning has the ability to bring students and teachers together in the Distance Education (DE) mode, it is not feasible in the healthcare based professions. AIM: To analyze healthcare students’ perceptions towards online learning due to the COVID-19 pandemic. MATERIALS AND METHOD: This qualitative, focus group-based study was done on the three focus groups consisting of 15 students each: medical, dental and allied sciences. Data were collected using observations from the recordings of the scheduled online interview which was approximately 30-minutes in length and the investigator asked questions from the pre-validated interview guide consisting of seven questions. Data was analyzed using the constant comparative method, which was then consequently categorized into two major areas: positive experiences and negative experiences. Positive experiences included: time flexibility, convenience, ease of connection and ease of learning; while negative experiences included instructor’s inexperience and a lack of interaction, self-motivation, isolation and missing out on practical learning. RESULTS: While responses of the positive experience ranged from “I have the flexibility to wake up few minutes before the lecture and directly log on for the lecture” to “Even during the closure of schools/ classes, I need not worry about lagging behind in my studies”; the negative experiences included statements like “the inexperience of the instructor in handling the teaching software led to difficulties and interruption in learning” and “I am a great loss due to missing patient work!! How am I going to become a good doctor if I don’t practise on patients under supervision of my staff”. CONCLUSION: While students are slowly adapting themselves to online based learning, those belonging to the healthcare sector are missing out on their practical classes which has the potential to hamper the quality of care being provided by them as future professionals

Geriatrics and Periodontics: A Review

Oral health is an important aspect of general well being and in the elderly population compromised oral care has been considered a major risk factor for various health problems. Hence oral-systemic diseases linkage is a special health concern for this elderly population and high quality of oral health care should be available to all regardless of age or circumstances

Tumor-treating fields plus chemotherapy versus chemotherapy alone for glioblastoma at first recurrence: a post hoc analysis of the EF-14 trial.

BACKGROUND: This post hoc analysis of the EF-14 trial (NCT00916409) of tumor-treating fields (TTFields) plus temozolomide versus temozolomide alone in newly diagnosed glioblastoma compared the efficacy of TTFields plus chemotherapy (physician\u27s choice) versus chemotherapy alone after first recurrence. METHODS: Patients on TTFields plus temozolomide continued TTFields plus second-line chemotherapy after first recurrence. Some patients on temozolomide alone crossed over after approval of TTFields for recurrent GBM. The primary efficacy outcome was overall survival (OS). RESULTS: After disease progression, 131 patients received TTFields plus chemotherapy and 73 chemotherapy alone. Thirteen patients in the original temozolomide-alone group crossed over to receive TTFields plus chemotherapy after disease progression, resulting in 144 patients receiving TTFields plus chemotherapy and 60 chemotherapy alone. Median follow-up was 12.6 months. Bevacizumab, alone or with cytotoxic chemotherapy, was the most frequent treatment. Median OS in the TTFields plus chemotherapy group was significantly longer versus chemotherapy alone (11.8 vs 9.2 months; HR: 0.70; 95% CI, 0.48-1.00; p=0.049). TTFields showed a low toxicity safety profile, as previously reported, with no grade 3/4 device-related adverse events. CONCLUSION: TTFields plus chemotherapy after first disease recurrence on TTFields plus temozolomide or temozolomide alone prolonged OS in patients in the EF-14 trial

Dental Caries Experience among Industrial Workers in Parwanoo, Himachal Pradesh, India

Background: Dental caries, the oral disease with multifactorial causes is a major public health problem leading go medically significant morbidity and impacting the general health of a population directly or indirectly. Dental caries is known to affect people from every population. Objective: To assess dental caries experience in permanent dentition among industrial workers in Parwanoo, Himachal Pradesh, India. Materials and Methods: This cross-sectional study was conducted among 1024 industrial workers of Parwanoo, Himachal Pradesh, in the age group of 16-55 years. Dental caries experience was assessed using WHO dentition status proforma (2013). Statistical analysis was done using SPSS 21.0. Results: Out of 1024 study subjects, 572 were males and 452 were females. Caries prevalence was found to be 47.46%. Mean decay-missing-filled teeth score of the population was 0.95 ± 0.45 and was found to be higher among females (1.06 ± 0.42) as compared to males (0.93 ± 0.38). Conclusion: The prevalence of dental caries in industrial workers is noteworthy. Essential requisites to bring this under control include awareness regarding good dental health, education on prevention of dental caries and implication of necessary measures for the provision of adequate dental care