Pecking at Pecking Order Theory: Evidence from Pakistan’s Non-financial Sector

This study tests the Pecking Order Theory for the capital structure of listed firms in Pakistan. As per Pecking Order Theory in capital structure formulation, internally generated resources would have first priority, followed by debt issuance where equity is used as a last resort. In its strong form, the Pecking Order Theory sustains that equity issues would never occur, whereas in its weak form, limited amounts of issues are acceptable. The methodology adopted in this empirical study involves cross-section regressions and the testing of hypotheses stemming from the underlying theory in its strong and weak forms. A sample of capital structure of non-financial firms listed at KSE is considered from 2001 to 2008. A statistical tool of panel data regression analysis is used to test different firms’ data. The value of R2, t-test and F-Stat indicate firms in KSE supporting the weak form of pecking order theory, i.e., the option of using internal equity and debt is more preferred and a limited amount of external equity is used for reinvestment and fund raising purposes

Two Loci, RiAF3 and RiAF4, Contribute to the Annual-Fruiting Trait in Rubus

Most Rubus species have a biennial cycle of flowering and fruiting with an intervening period of winter dormancy, in common with many perennial fruit crops. Annual-fruiting (AF) varieties of raspberry (Rubus idaeus and Rubus occidentalis L.) and blackberry (Rubus subgenus Rubus) are able to flower and fruit in one growing season, without the intervening dormant period normally required in biennial-fruiting (BF) varieties. We used a red raspberry (R. idaeus) population segregating for AF obtained from a cross between NC493 and ‘Chilliwack’ to identify genetic factors controlling AF. Genotyping by sequencing (GBS) was used to generate saturated linkage maps in both parents. Trait mapping in this population indicated that AF is controlled by two newly identified loci (RiAF3 and RiAF4) located on Rubus linkage groups (LGs) 3 and 4. The location of these loci was analyzed using single-nucleotide polymorphism (SNP) markers on independent red raspberry and blackberry populations segregating for the AF trait. This confirmed that AF in Rubus is regulated by loci on LG 3 and 4, in addition to a previously reported locus on LG 7. Comparative RNAseq analysis at the time of floral bud differentiation in an AF and a BF variety revealed candidate genes potentially regulating the trait.info:eu-repo/semantics/publishedVersio

Recent progress in two dimensional Mxenes for photocatalysis: a critical review

Transition metal carbides and nitrides, generally known as MXenes have emerged as an alternative to improve photocatalytic performance in renewable energy and environmental remediation applications because of their high surface area, tunable chemistry, and easily adjustable elemental compositions. MXenes have many interlayer groups, surface group operations, and a flexible layer spacing that makes them ideal catalysts. Over 30 different members of the MXenes family have been explored and successfully utilized as catalysts. Particularly, MXenes have achieved success as a photocatalyst for carbon dioxide reduction, nitrogen fixation, hydrogen evolution, and photochemical degradation. The structure of MXenes and the presence of hydrophilic functional groups on the surface results in excellent photocatalytic hydrogen evolution. In addition, MXenes’ surface defects provide abundant CO2 adsorption sites. Moreover, their highly efficient catalytic oxidation activity is a result of their excellent two-dimensional nanomaterial structure and high-speed electron transport channels. This article comprehensively discusses the structure, synthesis techniques, photocatalytic applications (i.e. H2 evolution, N2 fixation, CO2 reduction, and degradation of pollutants), and recyclability of MXenes. This review also critically evaluates the MXene-based heterostructure and composites photocatalyst synthesis process and their performance for organic pollutant degradation. Finally, a prospect for further research is presented in environmental and energy sciences

Biomedical and photocatalytic applications of biosynthesized silver nanoparticles: Ecotoxicology study of brilliant green dye and its mechanistic degradation pathways

© 2020 Elsevier B.V. The preparation of nanoparticles from biological materials is an economic and environmentally friendly strategy with several advantages. The current study is focused to synthesize silver nanoparticles using Petroselinum crispum plant extract. Various characteristics of biologically synthesized AgNPs were determined with UV–Visible (UV/Vis) Spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, and High-Resolution Transmission Electron Microscopy (HRTEM). The plasmonic resonance peak at 425 nm ensured the formation of AgNPs. The FTIR analysis showed that the as-synthesized particles contain alcoholic and polyphenolic constituents, which are responsible for their capping and reduction. The HRTEM results revealed spherical shape of AgNPs with size ranging from 25 to 90 nm. The as-synthesized particles demonstrated excellent antibacterial properties against Gram positive and Gram-negative bacteria. The antioxidant applications of the particles were determined with 2,2-diphenyle-1-picrylhydrazyl (DPPH). Moreover, the photocatalytic application of the synthesized AgNPs was evaluated for brilliant green dye (BG). The results demonstrated high degradation of BG due to small size and well-dispersed nature of AgNPs. Degradation products of BG were identified to suggest degradation pathways. The eco-toxicity of the BG and constituents derived from the dye were studied with Ecological Structure Activity Relationship (ECOSAR) software

Brief review: Applications of nanocomposite in electrochemical sensor and drugs delivery

The recent advancement of nanoparticles (NPs) holds significant potential for treating various ailments. NPs are employed as drug carriers for diseases like cancer because of their small size and increased stability. In addition, they have several desirable properties that make them ideal for treating bone cancer, including high stability, specificity, higher sensitivity, and efficacy. Furthermore, they might be taken into account to permit the precise drug release from the matrix. Drug delivery systems for cancer treatment have progressed to include nanocomposites, metallic NPs, dendrimers, and liposomes. Materials’ mechanical strength, hardness, electrical and thermal conductivity, and electrochemical sensors are significantly improved using nanoparticles (NPs). New sensing devices, drug delivery systems, electrochemical sensors, and biosensors can all benefit considerably from the NPs’ exceptional physical and chemical capabilities. Nanotechnology is discussed in this article from a variety of angles, including its recent applications in the medical sciences for the effective treatment of bone cancers and its potential as a promising option for treating other complex health anomalies via the use of anti-tumour therapy, radiotherapy, the delivery of proteins, antibiotics, and vaccines, and other methods. This also brings to light the role that model simulations can play in diagnosing and treating bone cancer, an area where Nanomedicine has recently been formulated. There has been a recent uptick in using nanotechnology to treat conditions affecting the skeleton. Consequently, it will pave the door for more effective utilization of cutting-edge technology, including electrochemical sensors and biosensors, and improved therapeutic outcomes

Performance evaluation of phosphonium based deep eutectic solvents coated cerium oxide nanoparticles for CO2 capture

The critical challenge being faced by our current modern society on a global scale is to reduce the surging effects of climate change and global warming, being caused by anthropogenic emissions of CO2 in the environment. Present study reports the surface driven adsorption potential of deep eutectic solvents (DESs) surface functionalized cerium oxide nanoparticles (CeNPs) for low pressure CO2 separation. The phosphonium based DESs were prepared using tetra butyl phosphoniumbromide as hydrogen bond acceptor (HBA) and 6 acids as hydrogen bond donors (HBDs). The as-developed DESs were characterized and employed for the surface functionalization of CeNPs with their subsequent utilization in adsorption-based CO2 adsorption. The synthesis of as-prepared DESs was confirmed through FTIR measurements and absence of precipitates, revealed through visual observations. It was found that DES6 surface functionalized CeNPs demonstrated 27% higher adsorption performance for CO2 capturing. On the contrary, DES3 coated CeNPs exhibited the least adsorption progress for CO2 separation. The higher adsorption performance associated with DES6 coated CeNPs was due to enhanced surface affinity with CO2 molecules that must have facilitated the mass transport characteristics and resulted an enhancement in CO2 adsorption performance. Carboxylic groups could have generated an electric field inside the pores to attract more polarizable adsorbates including CO2, are responsible for the relatively high values of CO2 adsorption. The quadruple movement of the CO2 molecules with the electron-deficient and pluralizable nature led to the enhancement of the interactive forces between the CO2 molecules and the CeNPs decorated with the carboxylic group hydrogen bond donor rich DES. The current findings may disclose the new research horizons and theoretical guidance for reduction in the environmental effects associated with uncontrolled CO2 emission via employing DES surface coated potential CeNPs

Effect of biochar modified with magnetite nanoparticles and HNO\u3csub\u3e3\u3c/sub\u3e for efficient removal of Cr(VI) from contaminated water: A batch and column scale study

© 2020 Elsevier Ltd Chromium (Cr) poses serious consequences on human and animal health due to its potential carcinogenicity. The present study aims at preparing a novel biochar derived from Chenopodium quinoa crop residues (QBC), its activation with magnetite nanoparticles (QBC/MNPs) and strong acid HNO3 (QBC/Acid) to evaluate their batch and column scale potential to remove Cr (VI) from polluted water. The QBC, QBC/MNPs and QBC/Acid were characterized with SEM, FTIR, EDX, XRD as well as point of zero charge (PZC) to get an insight into their adsorption mechanism. The impact of different process parameters including dose of the adsorbent (1–4 g/L), contact time (0–180 min), initial concentration of Cr (25–200 mg/L) as well as solution pH (2–8) was evaluated on the Cr (VI) removal from contaminated water. The results revealed that QBC/MNPs proved more effective (73.35–93.62-%) for the Cr (VI) removal with 77.35 mg/g adsorption capacity as compared with QBC/Acid (55.85–79.8%) and QBC (48.85–75.28-%) when Cr concentration was changed from 200 to 25 mg/L. The isothermal experimental results follow the Freundlich adsorption model rather than Langmuir, Temkin and Dubinin-Radushkevich adsorption isotherm models. While kinetic adsorption results were well demonstrated by pseudo second order kinetic model. Column scale experiments conducted at steady state exhibited excellent retention of Cr (VI) by QBC, QBC/MNPs and QBC/Acid at 50 and 100 mg Cr/L. The results showed that this novel biochar (QBC) and its modified forms (QBC/Acid and QBC/MNPs) are applicable with excellent reusability and stability under acidic conditions for the practical treatment of Cr (VI) contaminated water

A manually annotated Actinidia chinensis var. chinensis (kiwifruit) genome highlights the challenges associated with draft genomes and gene prediction in plants

Most published genome sequences are drafts, and most are dominated by computational gene prediction. Draft genomes typically incorporate considerable sequence data that are not assigned to chromosomes, and predicted genes without quality confidence measures. The current Actinidia chinensis (kiwifruit) 'Hongyang' draft genome has 164\ua0Mb of sequences unassigned to pseudo-chromosomes, and omissions have been identified in the gene models

Roles of a major O-acetylserine (thiol) lyase (OASTL) in cysteine biosynthesis, innate immunity and disease resistance in Arabidopsis : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Biology at Massey University, Palmerston North, New Zealand

O-Acetylserine (thiol) lyases (OASTLs) are evolutionary conserved proteins among many prokaryotes and eukaryotes that carry out sulphur acquisition and synthesis of cysteine. OASTL catalyses cysteine biosynthesis using O-acetylserine (OAS) and sulfide as substrates. OASTL also interact with another enzyme Serine acetyltransferase (SERAT) to facilitate the production of OAS. Cysteine-derived thiols and metabolites play an important function in regulating cellular redox conditions and modulate abiotic and biotic stress responses. The Arabidopsis thaliana genome encodes multiple OASTL isoforms that are targeted to different sub-cellular compartments. The cytosolic OASTL-A1 or known as ONSET OF LEAF DEATH3 (OLD3) is the major OASTL isoform due to its high OASTL activity. The old3-1 mutation causes a dysfunctional oastl-a1/old3-1 protein in vitro and was previously shown to cause autonecrosis in specific Arabidopsis accessions. To investigate why a mutation in a major OASTL isoform causes cell death and necrosis in some but not other accessions different mutations in OASTL-A1 were characterised in Arabidopsis accessions. Here it is shown that the old3-1 mutation causes an autoimmune syndrome and metabolic disorder, in the Ler-0 accession (parent) genetic background, but not in the reference accession Col-0. This is not the result of lack of functional OASTL-A1 or impaired cysteine biosynthesis. A Recognition of Peronospora Parasitica 1 (RPP1)-like disease resistance R gene, from an evolutionary divergent R gene cluster in Ler-0, shows a negative epistatic interaction to old3-1 and activates autonecrosis. The severity of autonecrosis was found to be dependent upon variations in temperature and day length. Next, the role of OASTL-A1 was also identified in resistance against infection with virulent and non-virulent Pseudomonas syringae pv. tomato DC3000 strains. Since OASTL also interacts with SERAT, old3-1 was found to negatively affect the interaction with SERAT in vivo, highlighting that the release of R-mediated immunity is associated with the loss of key functions associated with OASTL. Finally various mutations were generated in OASTL-A1 isoforms to identify the relevance between the loss of OASTL functions and R-mediated immunity. These results indicated that motifs in close proximity of old3-1 mutation play an important role in cysteine biosynthesis and therefore likely an important interface to affect R-mediated immunity. The study indicates a novel cross-talk between cysteine procuring a major OASTL isoform and components of plant immunity and further support emerging evidence that cysteine-derived metabolites function in immune signalling across kingdoms

Arabidopsis AGAMOUS Regulates Sepal Senescence by Driving Jasmonate Production

The signal that initiates the age-regulated senescence program in flowers is still unknown. Here we propose for the ephemeral Arabidopsis thaliana flower that it dies because of continued expression of the MADS-box transcription factor AGAMOUS (AG). AG is necessary for specifying the reproductive structures of the flower. Flowers of ag-1, which lack AG, exhibited delayed sepal senescence and abscission. The flowers also had reduced jasmonic acid (JA) content. Other anther-defective sterile mutants deficient in JA, defective in anther dehiscence 1 (dad1) and delayed dehiscence 2 (dde2), exhibited delayed sepal senescence and abscission as well. Manually pollinated dad1 flowers produced siliques but still had delayed senescence, demonstrating that absence of pollination does not cause delayed senescence. When ag-1, dad1 and dde2 flowers were sprayed with 100 μM methyl jasmonate, the sepal senescence and abscission phenotypes were rescued, suggesting that JA has a role in these processes. Our study uncovers a novel role for AG in determining the timing of death of the flower it helps develop and highlights a role for JA in sepal senescence