Regulation of parathyroid hormone gene expression by calcium and 1,25-dihydroxyvitamin D3

The two major regulators of parathyroid hormone (PTH) synthesis are calcium and the steroid hormone, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and the aim of this study was to investigate the molecular mechanisms of regulation by these modulators. Low extracellular calcium (0.4 mM) had no effect on steady-state preproPTH mRNA levels, but increased preproPTH mRNA levels associated with membrane-bound polysomes by 200%. Actinomycin D did not abolish this rise in polysomal preproPTH mRNA but increased mRNA levels by 1.6-fold in cells incubated in 0.4 and 1.0 mM calcium. Sucrose density gradient ultracentrifugation demonstrated that low calcium had no effect on polysomal size and, in addition, there was no evidence of a pool of non-ribosomal preproPTH mRNA. These data indicate that low calcium regulates PTH synthesis post-transcriptionally possibly by increasing the apparent half-life of preproPTH mRNA on polysomes. The binding sites for the vitamin D3 receptor (VDR) were localised using Southwestern and gel mobility shift assays which indicated two binding sites within the -451 to -348 bp and -668 to -452 bp fragments of the bovine PTH gene. To investigate functional activity of these putative VDRE, plasmids containing fragments of the -668 to +50 bp region were linked to the reporter gene, chloramphenicol acetyltransferase (CAT). The effect of 1,25(OH)2D3 on these constructs was investigated by transient transfection of oppossum kidney cells. 1,25(OH)2D3 suppressed CAT activity of the construct containing the -668 to +50 bp fragment by 22%, of the -668 to -452 bp construct by 27% and of the -451 to -348 bp construct was reduced by 25%. However, 1,25(OH)2D3 did not affect the activity of the construct containing the -347 to +50 bp fragment. These functional assays confirm the presence of two binding sites within the region -485 to -348 bp. The study presented demonstrated that low calcium regulates PTH synthesis post-transcriptionally and VDR binding sites were localised on the bovine PTH gene

In-vivo Per-cutaneous Single Fiber Reflectance Spectroscopy of Hepatic Steatosis in a Rat Model: Quantitative Assessment with Respect to Histopathology

The assessment of hepatic steatosis has implications on liver transplantation.Reflectance spectroscopy using single fiber is a minimally-invasive technique applied to probing of biological tissues for extracting tissue optical properties. The aim of this study is to evaluate if per-cutaneous in vivo single fiber reflectance spectroscopy (SfRS) could identify steatotic liver from lean liver and if SfRS could assess the grading of lipid level accumulated in liver in a diet induced rat model. Twelve rats were separated to four in the control group that were fed normaldiet and eight in the test group that were fed methionine-choline-deficient (MCD) diet. Percutaneous SfRS of the rat livers was performed under trans-abdominal ultrasound guidance and respiration gated data acquisition in day-0, day-13, day-27, day-41, and day-55. At each of the days of 13, 27, 41, and 55, one control rat and two test rats were euthanized after SfRS for collecting histopathology samples. The SfRS spectrum over 540-1000 nm was off-line processed for estimations of hemoglobin oxygen saturation, total hemoglobin concentration, lipid composition, effective scattering amplitude and power of the locally sampled liver parenchyma. Histopathology results of the twelve rats determined that all four control rats euthanized respectively on day 13, 27, 41 and 55 had insignificant lipid accumulation, two test rats euthanized on day 13 and another test rat euthanized on day 27 had mild lipid accumulation, one test rats euthanized on day 27 had moderate lipid accumulation, and four test rats, two test rats euthanized on day 41 and another two test rats euthanized on day 55 had severe lipid accumulation. SfRS results of the 4 rats originated in the control group and 8 test rats were compared and the steatotic livers shows a decreasing slope compares to normal liver. The total hemoglobin concentration also decreases as the lipid accumulation increases, starting 216.54�67.2 1???? in insignificant steatosis and ended up with 77.33�34.97???? in severe steatotic liver. There is an increase in scattering amplitude and power, scattering power changed as 0.33 � 0.0025 in insignificant, 34 � 0.0030 for mild, 0.35 on moderate and 0.35�0.0026 on severe steatotic liver at their respective days of euthanasia.Electrical Engineerin

Bright-light detector control emulates the local bounds of Bell-type inequalities

It is well-known that no local model - in theory - can simulate the outcome statistics of a Bell-type experiment as long as the detection efficiency is higher than a threshold value. For the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality this theoretical threshold value is $\eta_{\text{T}} = 2 (\sqrt{2}-1) \approx 0.8284$. On the other hand, Phys.\ Rev.\ Lett.\ 107, 170404 (2011) outlined an explicit practical model that can fake the CHSH inequality for a detection efficiency of up to $0.5$. In this work, we close this gap. More specifically, we propose a method to emulate a Bell inequality at the threshold detection efficiency using existing optical detector control techniques. For a Clauser-Horne-Shimony-Holt inequality, it emulates the CHSH violation predicted by quantum mechanics up to $\eta_{\text{T}}$. For the Garg-Mermin inequality - re-calibrated by incorporating non-detection events - our method emulates its exact local bound at any efficiency above the threshold. This confirms that attacks on secure quantum communication protocols based on Bell violation is a real threat if the detection efficiency loophole is not closed.Comment: 7 pages, 3 figure

Exploring Dark Tourism in Bangladesh: tourist engagement and perspectives in South Asia and beyond

This thesis explores the history and evolution of the dark tourism research field, with a particular focus on South Asia and specifically Bangladesh. Using global examples from online interview and an in-person case study of Rayer Bazar Boddhovumi or the Martyred Intellectuals Memorial, a site central to the Bangladesh Liberation War, the motivations of visitors to seek out such sites and their on-site and post-visit behaviour are analysed, during the COVID-19 pandemic. The work reflects on the commodification of death from both domestic and global perspectives. Appraising existing literature, this work expands the current theoretical framework to explore noteworthy aspects of dark tourism in Bangladesh. Centred around a constructivist research paradigm and employing methods derived from relativist, interpretivist, epistemological and ontological frameworks, innovative qualitative research ensures that data is interpreted and understood from a human perspective. The data gathered highlights Bangladeshi and South Asian perspectives and draws on non-South Asian experiences, to investigate how attitudes and behaviours at global and domestic levels shape national identity and heritage. Bangladesh is a growing tourism prospect, subject to increased government investment, which inspires patriotism and a sense of national pride in domestic visitors. The role of family tourism and ancestry is considered, as is the role of online reviewing and sharing of experiences. Visitors to dark tourism sites are reckoning with multiple motivations at once: paying their respects, mourning, and reinforcing beliefs. This culminates in the creation of a collective social memory. Bringing vital focus to the South Asian dark tourism industry, the research invites further critical attention

Single-photon detectors for satellite based quantum communications

With the growing use of online communications in our modern society, information security is becoming a big concern. Along with that, the progress in quantum computers is posing severe threats to such communications. Once powerful quantum computers are available, most of today's encryption schemes, which are based on computationally hard problems, will be broken within a short period. Researchers are therefore making a great effort to establish quantum-safe encryption schemes. One such scheme is quantum key distribution (QKD), which utilizes the laws of quantum mechanics. These cryptography protocols offer unconditional security to the communication between two distant parties by providing a secure way of sharing encryption keys between them. While over the last few decades QKD has continuously progressed, it is limited to a distance of up to several hundred kilometers using terrestrial quantum links. Satellites are therefore being considered to extend the QKD range for global coverage, although implementations of the satellite-based QKD infrastructure are still in their early stage. There are many aspects of QKD that need further assessment and advancement for establishing long-term satellite-based quantum communication (QC). My thesis works were focused on developing advanced systems for single-photon detectors and quantum sources. Single-photon avalanche diodes (SPADs) are the most viable option for satellite-based quantum communications. They must travel to outer space either for receiving quantum-states in the ground-to-satellite QC or for characterizing the quantum-sources in the satellite-to-ground QC. However, while in space, SPADs exhibit damage caused by the space radiation that gradually increases their dark counts. Performing QKD is not possible when the dark counts exceed a specific threshold. Hence, methods of reducing the detectors' dark counts by mitigating the damages would help to extend the SPADs' in-space useful lifetime. Laser annealing is one such effective method, found in lab experiments, to heal the radiation-induced detector damages. We now aim to carry out this method in low Earth orbit (LEO) to verify its in-orbit effectiveness. On that goal, we are building an annealing payload (APL) for a cube satellite (CubeSat) in collaboration with the University of Illinois at Urbana Champaign (UIUC). We, the University of Waterloo team, built one of the two segments of the APL-- a space-qualified detector module containing two Excelitas C30902SH and Excelitas SLiK detectors. Our miniaturized and compact module integrates the facilities required for the detector operation and laser annealing, as well as an active detector temperature control system. The operation of the detector module is highly flexible and software controllable. Our detector module will work together with the control board containing the laser annealing system (built by the UIUC team). Once the satellite has been launched in 2020, the in-orbit experiment will enable us to study the in-space SPAD radiation damage and their healing using the integrated annealing system. During a second project, we designed and built a new simple readout circuit for the negative feedback avalanche diodes (NFADs), which are free-running single-photon detectors at telecom wavelengths. These detectors suffer from strong afterpulsing effects, which limits their overall performances. Therefore, our readout system incorporates features to suppress NFAD afterpulses. We also used this custom readout to characterize two NFADs (from Princeton Lightwave) and assessed the performance of the new electronics. Our analysis showed that even at higher detection efficiencies, a 20 $\mu$s hold-off time after each avalanche event is enough to extensively reduce the number of afterpulses and to keep the dark count rate below 100 Hz at 192 K temperature. Both the detectors showed timing jitter of less than 75 ps FWHM at their maximum efficiencies. The best figure of merit is found to be 1.6$\times 10^7$, which is comparable to that of the high-performing superconducting nanowire single-photon detectors. This result demonstrates the suitability of our readout and the NFADs in various quantum optics applications, such as in long-distance quantum key distribution, where the detection rate is usually low. We then performed a blinding attack, which enables an Eavesdropper in QKD to gain information on the key, on these NFADs using bright illumination. These detectors are usually threshold detectors that generate a click when the optical power is above a certain threshold, otherwise they do not click. Blinding attack utilizes detectors' inability to resolve the photon numbers. During the experiment, we sent controlled optical pulses with a high time resolution to deterministically force detection at the detectors. The result demonstrated the NFADs' susceptibility to these attacks, which tells us to include countermeasures into the system to protect the communications. Finally, we built a quantum source to produce 785 nm polarized photons to implement decoy-state BB84 QKD. Our source utilized the sum-frequency generation scheme to generate 785 nm laser pulses. Its modulator system includes an intensity modulator and two-phase modulators in the Mach-Zehnder configuration to prepare polarized quantum states with different intensities. Our source provides a repetition rate of 500 MHz, which was successfully used in an airborne QKD demonstration with a moving receiver up to $10~ km$ distance. To summarize, my research projects are a contribution to the development of advanced devices, particularly single-photon detectors for quantum communications

Role of platelet distribution width and plateletcrit in assessment of nonthrombocytopenic preeclampsia and eclampsia in a tertiary care hospital of Odisha: an observational study

Background: Preeclampsia (PE) is a major cause of maternal and foetal morbidity and mortality in pregnancy. A decreased platelet count is observed during the progression of preeclampsia, and is considered a marker of the severity of preeclampsia. Considering the role of the PDW, PCT and platelet indices during the disease, the aim of this study was to evaluate the feasibility of using platelet indices as a severity marker for PE.Methods: This was a prospective, observational study, hospital-based study, from 2017-19 with 400 pregnant women being included on the basis of a predefined inclusion and exclusion criteria, through antenatal clinic, and labour room of the department of obstetrics and gynecology, S. C. B. Medical College, Cuttack, Odisha, India.Results: Study found that platelet count and plateletcrit showed a significant negative correlation with MAP whereas platelet distribution width showed a maximum positive correlation. In the preeclampsia group, subjects with PCT <0.22% were at risk of developing severe disease with a sensitivity of 53.5% and a high specificity of 85.5%. The AUC of 0.75 showed that it has a good predictability. In the eclampsia group, subjects with PCT <0.16% had a risk of developing severe disease with a sensitivity of 89.5% and specificity of 73.7%. The AUC 0.9 shows PCT to be a good predictor for assessing severity of eclampsia.Conclusions: This study suggests that platelet distribution width and plateletcrit are useful in risk evaluation of preeclampsia. These are a valid measurement tool to predict the severe progression of PE even when normal platelet counts are observed

Grammar teaching techniques at primary level in urban and rural areas of Bangladesh

This thesis is submitted in partial fulfillment of the requirements for the degree of Masters of Arts in English, 2015.Cataloged from PDF version of thesis.Includes bibliographical references (page 73 - 76).English language teaching and learning is still very much challenging for the teachers’ and students’ in Bangladesh. This paper shows the comparative study of how the grammar teaching techniques influence in rural and urban ESL classroom. The researcher conducted the study on randomly selected 75 students and 6 teachers of 8 ESL classrooms at the primary level in the both urban and rural areas of Bangladesh. Likert scale has been employed to collect the data from the participants. Quantitative method of analysis has been applied by the researcher with shows that teachers of urban and rural areas differ in grammar teaching techniques. This paper will have important role in guiding teachers to use different teaching techniques to enables language learning in both areas.Nur Nigar SultanaM.A. in Englis

Fetal congenital anomalies among consanguineous and non consanguineous marriage pregnant women attending in Bangabandhu Sheikh Mujib medical university

Background: Consanguineous marriage has been described as an important factor contributing to increased congenital malformations. Congenital anomalies began to emerge as one of the major childhood health problems and refers to any malformations that occur in a developing fetus. The aim of the study was to assess fetal congenital anomalies among consanguineous and non-consanguineous pregnant marriages.Methods: An observational study design was adopted. Setting: Data were collected from the fetal medicine unit at Bangabandhu Sheikh Mujib medical university, Dhaka, Bangladesh during the period, from April 2017 to March 2018. Sample: A total sample was 100 pregnant women (Consanguineous and non-consanguineous with fetal congenital anomalies) were recruited according to certain criteria. Two tools were used as materials. Structured interview tool which entailed socio-demographic data; medical history, past obstetrical history, and ultrasonographic fetal assessment record.Results: More than half of the fetuses in the consanguineous marriage group had multiple affected systems compared to one-quarter of fetuses in the non-consanguineous marriage group (68 and 24% respectively). In this study highly statistically, significant differences were found in central nervous system anomalies, followed by genitourinary, musculoskeletal and nonimmune hydrops fetalis. Prevalence of hydrocephalus was higher in the consanguineous marriage group compared to the non-consanguineous group, while the frequency of hydronephrosis was higher in non-consanguineous marriage group than consanguineous marriage group. Ubiquity of non-immune fetal hydrops was also higher in the non-consanguineous marriage group.Conclusions: The most affected system of the fetus was CNS, followed by the gastrointestinal, urinary, and Musculoskeletal systems. Consanguineous couples are recommended to have genetic counseling, premarital examination, and screening about hereditary diseases

Promising fortitude of vegetables worth in Dhaka city: A supply chain analysis

Vegetables trading require some vital support of integrated supply chain system and also depend on function of intermediaries, where transport facilities are most important The objective of paper is to analyze the role of vegetables supply chain in Bangladesh. The paper is exploring determination of vegetables price in Dhaka city which is ever-increasing fast with respect to rural market price in Bangladesh. Data were collected from different areas of Dhaka city and others districts for present study on vegetables price from rural to urban market where prices are very much discrimination. Analyzing the collected data it has been found that vegetables market and exploring the analysis of supply chain on the vegetables price is important. Study has further found that there have many barriers in vegetables market