Synthesis of Nitroxide based DNA binding Radioprotector for the Modification of Radiation Damage to DNA

© 2024 Rezwana Nasrin ChowdhuryTreatment during cancer often involves radiation therapy which requires ionizing radiation. However, surrounding normal healthy tissue gets affected during the process which decreases the quality of life and increases the occurrence of cancer later in life. One of the primary concerns of ionizing radiation is the production of free radicals of important biological structures such as DNA, RNA, proteins etc. due to stripping of electron during the high energy radiation phenomenon. The free radicals generated during radiotherapy could directly or indirectly attack the DNA molecule and break the DNA phosphate – deoxyribose backbone with consequences leading to permanent damage to the DNA ‘code’ (ie. mutation) and even cell death resulting in adverse effects on human health. Amifostine is the only approved radioprotector that quenches free radicals produced due to oxidative DNA damage. However, DNA damage still observed which led to the approach for synthesizing new radioprotector compounds with DNA binding ability. Previously White group have successfully synthesized minor groove binding compounds bibenzimidazoles that reduces the DNA strand breakage by electron donation to damaged DNA radical cations. Although high dose requirements lead to the idea of synthesizing nitroxide radicals attached DNA minor groove binding compounds with similar electron donating mechanisms as bibenzimidazoles for the radioprotection activity. This thesis is based on the synthesis of Distamycin analogue attached with different nitroxide radicals and analysing their DNA binding and radioprotection ability. Compounds 43, 45, 46, 48, 49, 50, and 57 were synthesized successfully with various radicals and their DNA binding ability were examined using UV spectroscopy, Circular dichroism, and molecular docking methods. All the compounds showed varying degrees of DNA binding

Optical Properties of Undoped and Indium-doped Tin Oxide Thin Films

Thin films of Tin Oxide (SnO2), having thickness of 200 nm, were formed on to glass substrates by thermal evaporation of high-purity SnO2 powder in vacuum at various substrate temperatures (TS), ranging between 25 and 200°C. SnO2 films with varying thickness were also prepared for a fixed TS = 100°C. Further, doping of SnO2 films with Indium (In) was accomplished through solid state diffusion process by successive deposition of SnO2 and In films and subsequent annealing at 200°C for 10 minutes. Both undoped and doped films were characterized optically by UV-VIS-NIR spectrophotometry in the photon wavelength ranging from 300 to 2500 nm. In the visible photon wavelength range, the average optical transmittance (T%) of the films with varying TS was found to be 85%. The maximum value of T % was found to be 89 % around the wavelength of 700nm. The variation of absorption coefficient with photon energy in the fundamental absorption region is the steepest for TS = 100°C. The sub-band gap (SBG) absorption is also minimum for this Ts. A fluctuating behavior of the band gap energy (Eg) with Ts is observed attaining the highest value of 3.59 eV for Ts = 100°C. The band gap energy increases with thickness but T% in the visible range decreases. The T% in the visible range varies inversely with indium doping, being highest for undoped films. The Eg increases upto 2 wt% In doping and gradually decreases for enhanced doping. It seems reasonable to conclude that In doping does not bring favorable optical characteristics. Undoped SnO2 films having thickness of 200 nm and formed at substrate temperature of 100°C yield essential acceptable properties for photovoltaic applications.DOI: http://dx.doi.org/10.3329/jbas.v35i1.7975Journal of Bangladesh Academy of Sciences, Vol.35, No.1, 99-111, 2011</jats:p

Comparison of Conventional and Automated Blood Culture Methods for The Diagnosis of Neonatal Septicemia

Neonatal Septicemia is a serious clinical syndrome and the definitive diagnosis is based on positive blood cultures which are obtained either by conventional or automated method. Early availability of proper isolation and identification of causative bacteria facilitates the timely initiation of appropriate antibiotic therapy. Thereby the present study was conducted to identify the bacterial causes of neonatal septicemia in the fastest possible time by comparing conventional and automated blood culture methods.This cross sectional study was done during the period from January 2018 to December 2018 and included clinically suspected cases of neonatal septicemia admitted to Neonatal Intensive Care Units of Chattogram Medical College Hospital (CMCH) and Chattogram Maa-Shishu O General Hospital (CMSOGH). Out of 178 samples, automated method detected 29 (16.3%) and conventional method detected 26 (14.6%) blood culture positive samples. The yield of bacteria by automated method was 100% and by conventional method was 89.7%. Number of bacteria isolated only by automated method were 3 (10.2%). Mean time for isolation of bacteria by automated method was 26.38 hours and by conventional method was 46.34 hours. Automated method detected 47.05% of isolated bacteria in first 24 hours but none of them were detected by conventional method within first 24 hours. Among the isolated bacteria, Klebsiella spp was most common (62.0%). Most of the isolates were resistant to Ampicillin, Cefotaxime and Ceftazidime. Analyzing the findings of the study, there was no significant difference in the rate of isolation in each time interval (p=0.157) of two methods but there was significant difference in the mean time of isolation of bacteria between two methods (p=0.000004).&#x0D; Bangladesh J Med Microbiol 2021; 15 (2): 12-18</jats:p

Plant Leaf Disease Detection and Classification Using Deep Learning: A Review and A Proposed System on Bangladesh's Perspective

&lt;p&gt;A very crucial part of Bangladeshi people's employment, GDP contribution, and mainly livelihood is agriculture. It plays a vital role in decreasing poverty and ensuring food security. Plant diseases are a serious stumbling block in agricultural production in Bangladesh. At times, humans can't detect the disease from an infected leaf with the naked eye. Using inorganic chemicals or pesticides in plants when it's too late leads in vain most of the time, deposing all the previous labor. The deep-learning technique of leaf-based image classification, which has shown impressive results, can make the work of recognizing and classifying all diseases trouble-less and more precise. In this paper, we've mainly proposed a better model for the detection of leaf diseases. Our proposed paper includes the collection of data on three different kinds of crops: bell peppers, tomatoes, and potatoes. For training and testing the proposed CNN model, the plant leaf disease dataset collected from Kaggle, is used which has 17430 images. The images are labeled with 14 separate classes of damage. The developed CNN model performs efficiently and could successfully detect and classify the tested diseases. The proposed CNN model may have great potency in crop disease management.&lt;/p&gt

Genomic characterization and comparative analysis of antibiotic resistance and virulence in Bangladeshi and global Klebsiella pneumoniae ST48 strains

Klebsiella pneumoniae is an opportunistic pathogen associated with nosocomial infections, known for its multidrug resistance (MDR) and biofilm-forming abilities. ST48 is a particularly concerning sequence type and an emerging international clone linked to global spread and MDR infections. This study examines the comprehensive genomic epidemiology of the local and global populations of K. pneumoniae ST48 strains using whole genomes sequence data. We performed phenotypic and genotypic characterization of a K. pneumoniae strain S3C and conducted molecular epidemiological analyses of local ST48 isolates in Bangladesh, followed by pan-genome and phylogenetic analyses of 397 global ST48 strains. The S3C strain was resistant to 17 out of 19 tested antibiotics and was a moderate biofilm former. Whole genome sequencing identified it as ST48 clonal type, with 13 acquired antibiotic resistance genes, 76 virulence-associated genes, and multiple mobile genetic elements. Comparative analysis of Bangladeshi ST48 strains indicated a high prevalence of MDR genes, particularly blaCTX-M-15, and a diverse array of virulence factors associated with biofilm formation, siderophore production, capsular biosynthesis and others. Pan-genome analysis of Bangladeshi ST48 strains revealed 8,030 genes, with 56.26% classified as core genes. In contrast, global ST48 strains had 16,307 genes, with 75.3% as accessory genes, highlighting extensive genomic plasticity. The phylogenetic analysis revealed that isolates from different regions clustered within the major clade, indicating the global dissemination of this sequence type. Our findings underscore the substantial genomic diversity and high resistance levels of K. pneumoniae ST48, emphasizing the need for targeted infection control measures and continuous surveillance