Coherent Detection of Discrete Variable Quantum Key Distribution using Homodyne Technique

In Discrete Variable Quantum Key Distribution (DV-QKD), homodyne detection method is frequently employed for its simplicity in use, effectiveness in terms of error correction, and suitability with contemporary optical communication systems. Being a coherent detection method, it relies on a local oscillator whose frequency is matched to that of the transmitted carrier's signal. In this paper we evaluate a Free Space Optical (FSO) DV-QKD system based on the KMB09 protocol using Homodyne detection under random phase fluctuation and depolarizing noise error. We present simulation results for System Efficiency and Quantum Bit Error Rate (QBER) for the proposed model. An obtained efficiency (approximately 25%) for our proposed DV-QKD system model shows that under atmospheric turbulence and noise effect, it is inline with the available analytical results. However, the inclusion of random phase fluctuation and noise led to higher-than-normal QBER which is anticipated in a real-world scenari

Effect of Different Preparations of Fluoride Gel on Salivary pH of Albino Rats

Objective: To evaluate the effect of different preparations of fluoride gels on the salivary pH of albino rats. Material and Methods: This experimental study consisted of 40 Albino rats randomly divided into four equal groups. Group A was the control group and received no intervention. Experimental group B received a topical application of 0.2% sodium fluoride gel. Experimental group C received topical application of stannous fluoride gel 0.4%. Experimental group D received topical application of APF gel (1.23% acidulated phosphate fluoride gel). The different preparations of the gels were applied once daily for 4 minutes on the occlusal surface of the right maxillary molars for 14 days. Salivary pH values were recorded immediately after the application of gels with the help of pH paper on day 1 and day 14. Results: There was a significant difference in the pH level of groups B, C and D after 14 days of fluoride application (p < 0.05). The non-parametric Kruskal Wallis test was applied for the comparison between the groups. Conclusion: This study concluded that all the fluoride gels after administration caused the acidic pH of saliva with the most acidic effect produced by APF gel

Determination of Shear Bond Strength of Nanocomposite to Porcelain and Metal Alloy

Objective: To compare porcelain and metal repair done with both nanocomposite and conventional composite. Material and Methods: A total of 30 cylinders were fabricated from Porcelain (I), Porcelain fused to metal (II), and metal (III) substrate each. Control group (A) was bonded with conventional micro-hybrid composite and experimental group (B) was bonded with nanocomposite in a 2 mm thickness. All specimens were thermocycled and stored in distilled water at 37 °C for 7 days. A universal testing machine was used to measure the Shear bond strength (SBS). The difference between bond strengths of the groups was compared using an independent t-test. Results: In all three groups, the SBS was higher in the experimental group as compared to the control group. The use of nanocomposite of metal alloy presented maximum shear bond strength, followed by samples of porcelain fused to metal and finally porcelain, showing the lowest values of SBS. Conclusion: Porcelain and alloys bonded with nanocomposite exhibit enhanced adhesiveness as well as aesthetic and mechanical properties. This subsequently would translate into providing higher clinical serviceability and durability and hence a cost-effective and accessible repair option for human welfare

Design, synthesis, characterization and computational docking studies of novel sulfonamide derivatives

This study reports three novel sulfonamide derivatives 4-Chloro-N-[(4-methylphenyl) sulphonyl]-N-propyl ben- zamide (1A), N-(2-hydroxyphenyl)-4-methyl benzene sulfonamide (1B) and 4-methyl-N-(2-nitrophenyl) ben- zene sulfonamide (1C). The compounds were synthesised from starting material 4-methylbenzenesulfonyl chlo- ride and their structure was studied through 1H-NMR and 13C-NMR spectra. Computational docking was per- formed to estimate their binding energy against bacterial p-amino benzoic acid (PABA) receptor, the dihydrop- teroate synthase (DHPS). The derivatives were tested in vitro for their antimicrobial activity against Gram+ and Gram- bacteria including E. coli, B. subtilis, B. licheniformis and B. linen. 1A was found active only against B. linen; 1B was effective against E. coli, B. subtilis and B. linen whereas 1C showed activity against E. coli, B. li- cheniformis and B. linen. 1C showed maximum activity with minimum inhibitory concentration (MIC) of 50, 100 and 150 µg/mL against E. coli, B. licheniformis and B. linen respectively. 1C exhibited maximum affinity to DHPS with binding free energy of -8.1 kcal/mol. It enriched in the top 0.5 % of a library of 7663 compounds, ranked in order of their binding affinity against DHPS. 1C was followed by 1B which showed a moderate to low level MIC of 100, 250 and 150 µg/mL against E. coli, B. subtilis and B. linen respectively, whereas 1A showed a moderate level MIC of 100 µg/mL but only agai st B. linen. These derivatives may thus serve as potential anti-bacterial alternatives against resistant pathogens

From text to e-text: perceptions of medical, dental and allied students about e-learning

ObjectiveMore than a year ago, Pakistan like the rest of the word, was hit by a global pandemic, due to which students of higher education had to accept the new era and adapt to the electronic learning environment for the very first time. This study aims to analyze the perceptions of medical, dental, and allied health students about e-learning in Pakistan. MethodsA descriptive, cross-sectional study was conducted throughout the country. A pre-validated, anonymous online questionnaire regarding demographics, past-experience of e-learning, advantages disadvantages of e-learning, and general perception of students towards e-learning was distributed. Descriptive statistics were computed for all demographics. Chi-square test was used to compare the differences of perceptions between pre-clinical year and clinical years students. Chi-square was used to compare overall category-wise positive and negative responses of students. The association between participant demographics and their perception towards e-learning was also calculated using chi square. ResultsA total of 1200 students participated in the study of which 797 (66.4%) were from pre-clinical years and 403 (33.6%) were from clinical years. The major advantage identified by all students was the ‘comfortable environment’ (70%) and ‘technical problems with IT equipment’ was listed as the biggest disadvantage (89%) of e-learning. For preclinical year students, ‘anxiety due to social isolation’ was selected as the biggest issue (p < 0.05) whereas, for clinical year students, it was ‘lack of patient interaction’ (p < 0.05). Overall, 72% of students had a negative perception of e-learning. ConclusionAfter more than a year of online studying, medical and allied students of Pakistan have expressed dissatisfaction towards e-learning. Student-teacher training, student counselling sessions, and innovative techniques need to be introduced to enhance student engagement and reduce pandemic stress.We are thankful to all the students who participated in the study. We are grateful to biostatistician Mr. Kashif Siddique for his inputs. Open Access funding was provided by the Qatar National Library

Determination of Shear Bond Strength of Nanocomposite to Porcelain and Metal Alloy

Objective: To compare porcelain and metal repair done with both nanocomposite and conventional composite. Material and Methods: A total of 30 cylinders were fabricated from Porcelain (I), Porcelain fused to metal (II), and metal (III) substrate each. Control group (A) was bonded with conventional micro-hybrid composite and experimental group (B) was bonded with nanocomposite in a 2 mm thickness. All specimens were thermocycled and stored in distilled water at 37 °C for 7 days. A universal testing machine was used to measure the Shear bond strength (SBS). The difference between bond strengths of the groups was compared using an independent t-test. Results: In all three groups, the SBS was higher in the experimental group as compared to the control group. The use of nanocomposite of metal alloy presented maximum shear bond strength, followed by samples of porcelain fused to metal and finally porcelain, showing the lowest values of SBS. Conclusion: Porcelain and alloys bonded with nanocomposite exhibit enhanced adhesiveness as well as aesthetic and mechanical properties. This subsequently would translate into providing higher clinical serviceability and durability and hence a cost-effective and accessible repair option for human welfare

Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020

Background: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. Methods: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity &lt;6/18, ≥3/60) and blindness (presenting visual acuity &lt;3/60). Estimates are age-standardized using the GBD standard population. Results: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by −27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). Conclusions: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.</p

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020