Transformations of Nitrogen and its Availability to Plants in Coal Mine Soils

The work of this thesis is concerned with the study of some aspects of nitrogen cycling in coal mine soils. A survey of sites in Central Scotland was made to assess which parts of the N cycle function in coal mine soils. 90 samples of widely varying properties were taken and various properties measured. The mineral N status of the waste material was low. Carbon dioxide evolution and nitrogen mineralization rates showed that a high level of carbon, but little nitrogen was turned over. Nitrification was measurable only on about half of the sites studied and was highly pH dependent, being inhibited below pH 5.0. However, even on sites above this pH, nitrification was not always measured which suggests that the introduction of nitrifying bacteria into the spoil was also an important factor. Some nitrogen was lost due to the fixation of ammonium by the clay minerals and much more was lost during incubation due to immobilization. The urease and amidase activities measured were similar to those in agricultural soils which suggests that the use of urea or amide-N fertilizers may be possible on these coal mine soils. Significant correlations of carbon turnover, urease activity, amidase activity and nitrification rate with each other, suggest the importance of organic matter for both microbial activity and enzyme stabilization. A laboratory incubation experiment was carried out to study the fate of nitrogen added as ammonium sulphate, urea or chicken manure in five selected samples of coal mine soils with different properties. Two samples showed no net mineralization of N at any stage in either the control, ammonium sulphate or urea treated samples. Two samples which were collected from the plots of an established organic manure trial, showed N mineralization rates comparable to agricultural soils suggesting the favourable effect of organic amendments in the long term on the establishment of N cycling. There were large losses of N in the first weeks of incubation, which were generally greater in the manure treated samples, where up to 69 % of added N was lost. These losses were attributed to a combination of ammonium fixation and immobilization. In the later stages of the incubations there was a clear contribution to mineralization from the chicken manure. Mineralization and nitrification rates were significantly improved by manure addition in all samples, especially in the acid soil where these processes did not occur with ammonium sulphate or urea addition. The manure not only increased the pH of the acid soil, but may have also added nitrifying bacteria to the soil. In general however, it would seem that these transformations of nitrogen species can occur in coal mine soils if other conditions, particularly pH, are suitable. A field experiment was set up to study nitrogen response on a reclaimed site for two years in 1986 and 1987. Seven rates of N fertilizer ranging between 0 and 150 kg N/ha as ammonium nitrate were added to triplicate plots. An attempt was also made to study the herbage response to N both in the presence and absence of added P and K, and to compare urea with ammonium nitrate. Nitrogen fertilizer significantly improved the herbage yield in both years, which was also reflected generally in higher N, P, and K contents in the herbage. In addition P and K tended to increase the yield of herbage when applied with N but their effect was not significant. Vegetation responded equally to both N fertilizers with no significant differences in herbage yield

IMPACT OF FAMILY OWNERSHIP ON FINANCING DECISIONS: A COMPARATIVE ANALYSIS OF COMPANIES LISTED AT THE KSE

The current study attempts to investigate debt and dividendpolicies under the umbrella of capital structure’s theories in bothorganizational types i.e. family owned business (FOB) and non-familyowned business (NFOB). Two threshold points of ownership structure(25% & 50%) were used to distinguishing FOB from NFOB. A sampleof 280 listed firms at the KSE was collected for the period 2002-13.Generalized Method of Moments (GMM) was applied on paneldata to estimate the coefficients of variables. The empirical resultsindicated the weak application of pecking order theory and higherpayout ratio in family firms comparatively. The study providedexplanation regarding speedier rebalancing the target capitalstructure of family firms due to easier access to debt and long termpresence of the family in the firm. However, FOBs smooth dividends tolesser extent than their counterpart NFOBs indicate lower agencyand information asymmetry problems in them. SECP as well as stockexchanges are advised to bring required changes in corporate lawsto ensure lucid and verifiable disclosure regarding dividend policyin their reports, prospectus and websites et

A NOVEL CELL BY CELL ARTIFICIAL NEURAL NETWORKS APPROACH FOR PREDICTING THE TEMPERATURE OF STEADY STATE, INCOMPRESSIBLE, LAMINAR FLOWS

A cell-by-cell artificial neural network approach is used to predict the temperature field of steady-state, incompressible, laminar flows in a two-dimensional computational domain. The temperature field is characterized by the initial flow velocity, fluid temperature and the temperature of the wall boundaries. Two types of neural network architectures are developed in this research, namely cascade-forward and feedforward models. Both models are trained using Levenberg-Marquardt and Bayesian regularization backpropagation algorithms. The training data for the models are obtained by solving the Navier-Stokes equations for steady-state, incompressible, heat conducting laminar flow in two-dimensional domain using commercial ANSYS Fluent software. The results show that the predicted values produced by the ANN models are in good agreement with the CFD simulation data. Even though the introduction of artificial neural networks at the cell level increases the complexity of the training process, this drawback is compensated by the increase in flexibility (generality) of the models. More importantly, the results show that the cell-by-cell artificial neural network approach is capable of providing an accurate prediction of the temperature field for the fluid flow investigated in this research, as indicated by the statistical indices used to evaluate the performance of prediction models. The feedforward ANN model trained using the Bayesian regularization backpropagation algorithm gives the most accurate predictions among all models

p62-Keap1-NRF2-ARE Pathway: A Contentious Player for Selective Targeting of Autophagy, Oxidative Stress and Mitochondrial Dysfunction in Prion Diseases

Prion diseases are a group of fatal and debilitating neurodegenerative diseases affecting humans and animal species. The conversion of a non-pathogenic normal cellular protein (PrPc) into an abnormal infectious, protease-resistant, pathogenic form prion protein scrapie (PrPSc), is considered the etiology of these diseases. PrPSc accumulates in the affected individual’s brain in the form of extracellular plaques. The molecular pathways leading to neuronal cell death in prion diseases are still unclear. The free radical damage, oxidative stress and mitochondrial dysfunction play a key role in the pathogenesis of the various neurodegenerative disorders including prion diseases. The brain is very sensitive to changes in the redox status. It has been demonstrated that PrPc behaves as an antioxidant, while the neurotoxic prion peptide PrPSc increases hydrogen peroxide toxicity in the neuronal cultures leading to mitochondrial dysfunction and cell death. The nuclear factor erythroid 2-related factor 2 (NRF2) is an oxidative responsive pathway and a guardian of lifespan, which protect the cells from free radical stress-mediated cell death. The reduced glutathione, a major small molecule antioxidant present in all mammalian cells, and produced by several downstream target genes of NRF2, counterbalances the mitochondrial reactive oxygen species (ROS) production. In recent years, it has emerged that the ubiquitin-binding protein, p62-mediated induction of autophagy, is crucial for NRF2 activation and elimination of mitochondrial dysfunction and oxidative stress. The current review article, focuses on the role of NRF2 pathway in prion diseases to mitigate the disease progression

Protocol optimization for deoxyribonucleic acid (DNA) extraction from dried, fresh leaves, and seeds of groundnut (Arachis hypogaea L.)

Consistent isolation of best quality deoxyribonucleic acid (DNA) from peanut (Arachis hypogaea L.) is particularly problematic due to the presence of phenolic compounds and polysaccharides. Inconsistencies in extraction results can be attributed to the age and growth stages of the plant material analyzed. Mature leaves have higher quantities of polyphenols, tannins and polysaccharides that can contaminate DNA during isolation. In this study, we used fresh and dried leaves as well as seeds for optimization of high quality DNA isolation protocols from A. hypogaea. The DNA extracted with three different methods cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and cesium chloride (CsCl) density gradient) were comparatively studied by polymerase chain reaction (PCR) analysis in terms of quantity and quality. High quality genomic DNA was obtained from fresh leaves by modified CTAB methods. The DNA obtained ranged from 1 to 2.5 ng/μl. DNA obtained by this method was strong and reliable showing its compatibility for simple sequence repeat (SSR) analyses. The SDS based methodology give large quantities of DNA contaminated with polysaccharides. Fresh leaves also gave best result in SDS method. The quantity and quality of DNA obtained was very poor in all the tested methods in case of dried leaf tissues. The current protocol will probably be useful for the extraction of high-molecular weight DNA from other plant materials containing large amounts of secondary metabolites and essential oils.Key words: Polysaccharides, polyphenols, tannins, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), cesium chloride (CsCl), secondary metabolites, SSR

Identification and Comprehensive Genome-Wide Analysis of Glutathione S-Transferase Gene Family in Sweet Cherry (Prunus avium) and Their Expression Profiling Reveals a Likely Role in Anthocyanin Accumulation

Glutathione S-transferases (GSTs) in plants are multipurpose enzymes that are involved in growth and development and anthocyanins transportation. However, members of the GST gene family were not identified in sweet cherry (Prunus avium). To identify the GST genes in sweet cherry, a genome-wide analysis was conducted. In this study, we identified 67 GST genes in P. avium genome and nomenclature according to chromosomal distribution. Phylogenetic tree analysis revealed that PavGST genes were classified into seven chief subfamily: TCHQD, Theta, Phi, Zeta, Lambda, DHAR, and Tau. The majority of the PavGST genes had a relatively well-maintained exon–intron and motif arrangement within the same group, according to gene structure and motif analyses. Gene structure (introns-exons) and conserved motif analysis revealed that the majority of the PavGST genes showed a relatively well-maintained motif and exons–introns configuration within the same group. The chromosomal localization, GO enrichment annotation, subcellular localization, syntenic relationship, Ka/Ks analysis, and molecular characteristics were accomplished using various bioinformatics tools. Mode of gene duplication showed that dispersed duplication might play a key role in the expansion of PavGST gene family. Promoter regions of PavGST genes contain numerous cis-regulatory components, which are involved in multiple stress responses, such as abiotic stress and phytohormones responsive factors. Furthermore, the expression profile of sweet cherry PavGSTs showed significant results under LED treatment. Our findings provide the groundwork for future research into induced LED anthocyanin and antioxidants deposition in sweet cherries

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 years; 78.2% included were male with a median age of 37 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

Shape Memory Alloy-Based Fluidically Reconfigurable Metasurfaced Beam Steering Antenna

A low-cost actuator-based fluidically programmable metasurface (FPMS) antenna is proposed to solve the slow tuning speed problem of the manually fluidic based reconfigurable antennas. The FPMS-based antenna is probe-fed and comprises a $4\times4$ square ring metasurface as a superstrate. Moreover, two shape memory alloy (SMA)-based electrically-controlled actuators are employed in the design for controlling the position of the 3D-printed fluidic channels beneath the metasurface along the axes of the radiating slots of the patch antenna. This results in beam-steering of over ±20° in the elevation plane, with a peak gain of 9.1 dBi. It is worth mentioning that compared to conventional electronic tuning technologies where the switches are employed on the top of the radiating aperture of the antenna, which usually deteriorate the antenna performance, the SMA spring actuators do not deteriorate the performance as these are not interacting with the radiating aperture. The proposed antenna was designed and simulated using CST MWS, and the prototype was fabricated and measured. The simulated and measured results are in good agreement, which corroborates the adequacy of the proposed concept. By incorporating the SMA-based fluidic actuators, the proposed antenna is simple and highly efficient as compared to metasurface-based beam-steering antennas reported in the literature thus far