Molecular development of a thermostable β-glucosidase for modification of natural products

The gene encoding a β-glucosidase originating from the extreme thermophile Thermotoga neopolitana has been cloned and expressed in Escherichia coli. The aim was to produce a thermostable enzyme that could be used to remove sugar residues from glucosylated natural products classified as flavonoids by applying a method combining extraction in hot pressurized water with enzymatic hydrolysis. The β-glucosidase (termed TnBgl1A in this thesis) is a member of family 1 of glycoside hydrolase (GH1). The enzyme has an apparent unfolding temperature of 101.9 °C and a molecular weight of 52.6 kDa. The activity of TnBgl1A was first analysed using the model substrate para-nitrophenyl-β-D-glucopyranoside (pNPGlc), demonstrating that a single glucosyl residue (typical for β-glucosidases) is released by this enzyme. Hydrolysis of glucosylated forms of the natural product quercetin (the major flavonoid in yellow onion) was found to be dependent on the position of the glucosylation (see below). Expression in E. coli resulted in a relatively large fraction of insoluble target protein. To improve the folding of TnBgl1A during production, different strategies were then applied: I) the gene was constructed synthetically and codons were optimized to match codon usage in E.coli, II) the gene was cloned in frame with a signal peptide to translocate the protein to the periplasmic space, and III) the gene was co-expressed with genes encoding molecular chaperones. Among these strategies the co-expression of the gene with chaperones worked best, and the improved folding resulted in an increased fraction of soluble, active enzyme. The TnBgl1A was tested for the hydrolysis of quercetin-glucosides, which are antioxidants classified as flavonoids present in onion, and composed of a polyphenolic backbone glucosylated at two different positions (Q3, Q4´, and the diglucoside Q3,4´). The aglycone form of quercetin is a more potent antioxidant than the glucosylated forms. The activity of TnBgl1A for Q3 was lower compared to its activity on quercetin-4´-glucoside (Q4´). To improve hydrolysis of Q3, mutations were introduced in the enzyme, based on a structure model of TnBgl1A. The mutant N221S/P342L showed increased efficiency towards Q3 as well as for Q4´ compared to wild-type. This showed that the position and nature of this residue in the active site is important for substrate specificity and that by careful selection the specificity can be changed for different substrates. Therefore, the mutation studies were extended and the active site region was targeted for further mutagenesis. Among the changes introduced, the mutagenesis of the neighbouring residue, N220S, was also found to influence activity, and this variant had a higher specific activity for quercetin-glucosides. TnBgl1A and one of the best performance mutants (N221S/P342L) were immobilized on acrylic support to allow recycling of the enzyme in experiments coupling hot water extraction of quercetin-glucosides with enzymatic hydrolysis. The activity of the immobilised enzyme was analysed in batch experiments using pNPGlc as model substrate and showed not only that the enzyme remained active after immobilisation, but that the thermal stability of the enzyme improved slightly. The effect of additives on immobilisation was studied and, as glucose is an activator for the enzyme, the addition of glucose during immobilisation resulted in a slight increase in the specific activity. In the case of bovine serum albumin (BSA), the original activity was recovered after three months of storage by incubation with BSA for 24 hours. In conclusion, the work in the present thesis shows that TnBgl1A is an effective biocatalyst for the conversion of quercetin-glucosides to quercetin. It was also found that, in the production step, more soluble enzymes can be obtained if they are co-expressed with chaperones. The specificity of the enzyme can be changed by changing a single amino acid in the active site, and the improved hydrolysis of Q3 found for two single mutants (N220S and N221S) is caused by indirect changes in interactions, which may lead to a better fit of the quercetin backbone in the active site. As the modification of amino acids in the active site requires a deep understanding of the structure, it is hoped that the results reported here can contribute to the creation of, new mutants with better activity guided by predictions based on the current results. In this research, we have shown that both free and immobilised enzyme can be coupled to the hot water extraction process and that the immobilised enzyme can be used in an on-line process for hydrolysis of flavonoid glucosides. Further improvements can also be made in such combined processes, both concerning the conditions for the extraction and hydrolysis

Diet and Sports Performance

The focus of this research study was to assess the perception of athletes about diet and its role in the maintenance of performance. The target population of this research study was comprised of all the players of different sports clubs of District Bannu. Two hundred and six (206) players were randomly selected as sample of the study. For the collection of data, the researcher developed a closed form of questionnaire. The developed questionnaire personally served by the researcher among the respondents and collected back after getting it filled by the respondents. The collected data were tabulated and analyzed by using percentage and mean average as statistical tool. After data analysis, the researcher arrived at conclusion that proper diet is the basic requirement of athletic performance. The data also revealed that carbohydrates, protein, fats, vitamins, minerals and water are more important to consume in proper amount for sports participation. Keywords: Athlete, Diet, Training, Sports Performanc

A NUMERICAL INVESTIGATION REALIZING THE FLOW STRUCTURE AND HEAT TRANSFER PERFORMANCE OF THE POTENTIAL IMPINGING JETS

The demand for improvement in the performance of gas turbines has led to the consideration of flows at increasingly high temperatures, but this introduces challenges in terms of maintaining their structural integrity and preventing overheating. To respond to these challenges, gas turbine manufacturers have turned to internal cooling, and jet impingement provides an effective solution for cooling the leading edge of the blades of gas turbines. In this study, the author numerically simulated the cooling performance of the leading edge of the blades of a gas turbine under constant heat flux by using five configurations of jet impingement: a steady jet, a sweeping jet, a swirling jet, a Chevroned Steady jet, and a Chevroned Sweeping jet. Fluidic oscillators are known for their sweeping behavior and expansive coverage of the cooling surface while swirling jet owing to spiral geometry add tangential velocity component to the fluid which combines with the axial velocity component that generates enhanced momentum transfer area. On other hand by chevron attachment at exit of the nozzle are known to excite the jet downstream by forming coherent vortical structures that increase turbulence and, thus, promote the rates of mixing and heat transfer. These potential jets are compared at stationary and rotatory conditions (3000, 10000, 15000 rpm’s) and results showed that at the stationary condition Chevroned Sweeping jet outperformed the steady jet configurations owing to oscillating jet impingement and a higher intensity of turbulence that increased the entrainment of jet flow. Under the configuration involving a Chevroned Sweeping jet, the target surface recorded an average Nusselt number that was 19.23% higher than that with a steady jet without chevrons, along with more uniform distributions of the temperature and the Nusselt number due to oscillations of the sweeping jet and higher turbulence at the exit of the nozzle with chevrons. While for rotation case sweeping jet performed the best as chevroned nozzles due to higher disturbance generated high recirculation regions leading to hotspots formation while swirling jet performed worse of all as swirling strength was negatively impacted due to rotatory motion. It can be concluded that the addition of chevrons and swirling angle improved heat transfer rate for sweeping and steady jet. However, upon rotation sweeping jet predominantly captures the best performance amongst all the jets

Impact of age dominating over the pre-existing comorbidities influencing the D-Dimer levels in SARS-COV-2 infection

COVID-19-related disease severity is more commonly seen in elderly patients with comorbidities, and hypercoagulability has been demonstrated to be involved in the disease progression. This study aimed to evaluate the level of D-Dimer in hospitalized SARS-COV-2 infected patients and to determine the influence of age, gender, Body Mass Index (BMI), and comorbidities on D-dimer value and correlate it with disease severity. This case-control retrospective study retrieved patient data on demographic characteristics, vital functions, comorbidities, disease severity [National Institutes of Health (NIH) classification], and D-dimer from medical records of Thumbay University Hospital, Ajman, United Arab Emirates. SPSS-Version-28 was used for data analysis; a Chi-Square test was done to compare the distribution of comorbidities and disease severity between demographic categories. An independent sample t-test and one-way ANOVA were done to compare mean levels of D-Dimer between two or more categories, respectively. The majority of patients were males, ˃40 years of age, overweight/obese, with 30% having one comorbidity and 20% having ≥2 comorbidities. Among the total, three-quarters had moderate, and one-quarter had severe disease conditions, irrespective of gender or BMI, with an increasing trend of severe cases in the older age group and with comorbidities. Increased D-dimer levels were seen in the majority of SARS-COV-2-infected hospitalized patients, with age as the primary determinant, irrespective of absence or presence of comorbidity, though the trend of higher prevalence of elevated D-dimer value in the multiple comorbid groups and more severe condition was observed. Supporting SAR-COV-2 as a coagulopathic condition, D-dimer concentrations can be a helpful marker of disease progression and can be considered to guide the clinical treatment

The utility of Magnetoencephalography in multiple sclerosis – A systematic review

Introduction: Magnetoencephalography (MEG), allows for a high degree temporal and spatial accuracy in recording cortical oscillatory activity and evoked fields. To date, no review has been undertaken to synthesise all MEG studies in Multiple Sclerosis (MS). We undertook a Systematic Review of the utility of MEG in MS. / Methods: We identified MEG studies carried out in MS using EMBASE, Medline, Cochrane, TRIP and Psychinfo databases. We included original research articles with a cohort of minimum of five multiple sclerosis patients and quantifying of at least one MEG parameter. We used a modified version of the JBI (mJBI) for case-control studies to assess for risk of bias. / Results: We identified 30 studies from 13 centres involving at least 433 MS patients and 347 controls. We found evidence that MEG shows perturbed activity (most commonly reduced power modulations), reduced connectivity and association with altered clinical function in Multiple Sclerosis. Specific replicated findings were decreased motor induced responses in the beta band, diminished increase of gamma power after visual stimulation, increased latency and reduced connectivity for somatosensory evoked fields. There was an association between upper alpha connectivity and cognitive measures in people with MS. Overall studies were of moderate quality (mean mJBI score 6.7). / Discussion: We find evidence for the utility of MEG in Multiple Sclerosis. Event-related designs are of particular value and show replicability between centres. At this stage, it is not clear whether these changes are specific to Multiple Sclerosis or are also observable in other diseases. Further studies should look to explore cognitive control in more depth using in-task designs and undertake longitudinal studies to determine whether these changes have prognostic value

Reproductive tract infections among married women in peri-urban areas of Karachi, Pakistan: A population-based study

Background: Reproductive Tract Infections (RTIs) is a major public health problem. In Pakistan, there is dearth of information about the prevalence of RTIs among women and their health seeking behavior. A study was conducted to determine the prevalence, number and types of RTIs among women residing in squatter settlements in Karachi and their health seeking behavior.Methods: The respondents were married non-pregnant women aged 15–49 years residing in peri-urban areas of Karachi, Pakistan. The interviews with women were followed by their physical and pelvic examinations. Samples swabs collected from vagina and endocervix were tested in laboratory.Results: Overall, 23.8% of the women had laboratory-diagnosed RTIs. Nearly 2.6% had trichomoniasis and 1.7% were positive for syphilis. Bacterial vaginosis was diagnosed in 8.8% and vaginal candidiasis in 13.2 %.Conclusion: The study indicates a high prevalence of RTIs among women with Bacterial vaginosis and trichomoniasis to be the most prevalent endogenous infection and STI respectively. The women considered many symptoms as normal and did not seek treatment. These are the cases that have a potential to remain infected for a long time

6G secure quantum communication: a success probability prediction model

© 2024 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/The emergence of 6G networks initiates significant transformations in the communication technology landscape. Yet, the melding of quantum computing (QC) with 6G networks although promising an array of benefits, particularly in secure communication. Adapting QC into 6G requires a rigorous focus on numerous critical variables. This study aims to identify key variables in secure quantum communication (SQC) in 6G and develop a model for predicting the success probability of 6G-SQC projects. We identified key 6G-SQC variables from existing literature to achieve these objectives and collected training data by conducting a questionnaire survey. We then analyzed these variables using an optimization model, i.e., Genetic Algorithm (GA), with two different prediction methods the Naïve Bayes Classifier (NBC) and Logistic Regression (LR). The results of success probability prediction models indicate that as the 6G-SQC matures, project success probability significantly increases, and costs are notably reduced. Furthermore, the best fitness rankings for each 6G-SQC project variable determined using NBC and LR indicated a strong positive correlation (rs = 0.895). The t-test results (t = 0.752, p = 0.502 > 0.05) show no significant differences between the rankings calculated using both prediction models (NBC and LR). The results reveal that the developed success probability prediction model, based on 15 identified 6G-SQC project variables, highlights the areas where practitioners need to focus more to facilitate the cost-effective and successful implementation of 6G-SQC projects.Peer reviewe

Sales Management Portal

In any business organization, sales is the department that generates revenue. No matter how good your manufacturing operation is, how cutting-edge your technology is, how tight your financial goals are or how progressive and forward-thinking your management techniques are, you must still have a sales mechanism in place, or everything else is useless. Why is this project important? A sales management portal is a phenomenal way to explain the importance of marketing or sales within the organization. it involves the possible way for all the people to get connected and get the information they may need for potential sales. Indeed, portal is a doorway for the process of marketing and get to the next step of any business. What problem does it solves? This project will cover all the options about the selling activities, where management can easily access the detailed report about the sales team and managing their performance. Therefore, the management will have the option of accessing updated information through their DASHBOARD and can leave important notes to the employee. The other important benefit includes, all the information about the clients and the communication between the sales team and the managers will be easily accessible for future purposes. Does it provide a new application/service, replace an existing application/service, or enhance an existing application/service? This project will cover more focused functionalities, such as: USER FRIENDLY OPTIONS: the designed features used in this project is easily understandable to anyone. NOTES: this is an additional feature, where the sales team can leave their opinion or comments in order to know the management about the ongoing work, which in turn the management can give their feedbacks. OPPORTUNITY: in addition to above, there is another feature included in this project where the sales person can easily evaluate the possibility of having opportunities to finalize the initiation of project. The Sales Management Portal will be available for its final presentation and release before 5th December 2016

Direct bandgap materials based on the thin films of SexTe100 - x nanoparticles

In this study, we fabricated thin films of Se(x)Te(100 − x) (x = 0, 3, 6, 9, 12, and 24) nanoparticles using thermal evaporation technique. The results obtained by X-ray diffraction show that the as-synthesized nanoparticles have polycrystalline structure, but their crystallinity decreases by increasing the concentration of Se. They were found to have direct bandgap (E(g)), whose value increases by increasing the Se content. These results are completely different than those obtained in the films of Se(x)Te(100 − x) microstructure counterparts. Photoluminescence and Raman spectra for these films were also demonstrated. The remarkable results obtained in these nanoparticles specially their controlled direct bandgap might be useful for the development of optical disks and other semiconductor devices