Effect of shaking procedures on the neutral ammonium citrate soluble phosphate fraction in fertiliser materials

The effect of four types of shaker, extraction time and temperature on the quantity of phosphate extracted by neutral ammonium citrate was evaluated at two research laboratories. Six unprocessed phosphate rocks, and five partially acidulated and four fully acidulated phosphate fertilisers were investigated. Compared with the more than 10-fold variation in the solubility of the two reactive phosphate rock materials, Sechura and North Carolina, that resulted from using different types of shaker, the solubility of the unreactive phosphate rock materials and the partially and fully acidulated phosphate fertilisers in citrate was influenced to a much smaller degree by the action of the shaker. Sechura was less soluble in citrate that all four unreactive phosphate rock materials when either of the two horizontal shakers were used. This is totally at odds with the documented differences in the chemical reactivity' and agronomic effectiveness of these phosphate rock materials. Not until a wrist-action shaker was used did the solubility of Sechura and North Carolina exceed that of the unreactive materials and approach that obtained with a full end-over-end shake. The neutral ammonium citrate procedure needs to include a more precise definition of the type of shaker and its speed. In laboratories where temperature-controlled extraction is not available, a 24-h shake at 20°C using an orbital or end-over-end apparatus could be an alternative to the standard 1-h extraction at 65°C.     

Nanofiber Aerogels with Precision Macrochannels and LL-37-Mimic Peptides Synergistically Promote Diabetic Wound Healing

Fast healing of diabetic wounds remains a major clinical challenge. Herein, this study reports a strategy to combine nanofiber aerogels containing precision macrochannels and the LL-37-mimic peptide W379 for rapid diabetic wound healing. Nanofiber aerogels consisting of poly(glycolide-co-lactide) (PGLA 90:10)/gelatin and poly-p-dioxanone (PDO)/gelatin short electrospun fiber segments are prepared by partially anisotropic freeze-drying, cross-linking, and sacrificial templating with 3D printed meshes, exhibiting nanofibrous architecture and precision micro-/macrochannels. Like human cathelicidin LL-37, W379 peptide at a concentration of 3 µg mL⁻¹ enhances the migration and proliferation of keratinocytes and dermal fibroblasts in a cell scratch assay and a proliferation assay. In vivo studies show that nanofiber aerogels with precision macrochannels can greatly promote cell penetration compared to aerogels without macrochannels. Relative to control and aerogels with and without macrochannels, adding W379 peptides to aerogels with precision macrochannels shows the best efficacy in healing diabetic wounds in mice in terms of cell infiltration, neovascularization, and re-epithelialization. The fast re-epithelization could be due to the upregulation of phospho-extracellular signal-regulated kinase (p38 mitogen-activated protein kinase) after treatment with W379. Together, the approach developed in this study could be promising for the treatment of diabetic wounds and other chronic wounds.     

A model for modulus development of dual-cure resin systems

A phenomenological model for cure-dependent modulus is described for materials undergoing a two-stage curing reaction. These dual-cure resin systems commonly use a thermally activated reaction in the second stage with temperatures exceeding the glass transition temperature of the intermediate product. This leads to a non-linear development of the elastic modulus, with an observable softening effect and the potential for large structural deformations. In this study, the elastic modulus was measured at discrete levels of thermal conversion and processing temperatures. The results are used to determine the cure and temperature dependent-modulus and create a model capable of following the modulus development throughout the entire thermal processing stage. Applications and a processing guideline are discussed.     

Harnessing Multiple,Nonproteogenic Substitutions to Optimize CSP:ComD Hydrophobic Interactions in Group 1 Streptococcus pneumoniae

Streptococcus pneumoniae (pneumococcus) is a human pathobiont that causes drastic antibiotic-resistant infections and is responsible for millions of deaths universally. Pneumococcus pathogenicity relies on the competence-stimulating peptide (CSP)-mediated quorum-sensing (QS) pathway that controls competence development for genetic transformation and, consequently, the spread of antibiotic resistance and virulence genes. Modulation of QS in S. pneumoniae can therefore be used to enervate pneumococcal infectivity as well as minimize the susceptibility to resistance development. In this work, we sought to optimize the interaction of CSP1 with its cognate transmembrane histidine kinase receptor (ComD1) through substitution of proteogenic and nonproteogenic amino acids on the hydrophobic binding face of CSP1. The findings from this study not only provided additional structure–activity data that are significant in optimizing CSP1 potency, but also led to the development of potent QS modulators. These CSP-based QS modulators could be used as privileged scaffolds for the development of antimicrobial agents against pneumococcal infections.     

Optimization of the bistability property for flexible display by an integrated approach using Taguchi methods,neural networks and genetic algorithms

Flexible display has many advantages including lower power consumption, lighter weight, and thinness. Therefore, several companies strive to develop new applications for flexible displays to keep abreast of market opportunities. Flexible displays depend on the reflection of module processes; thus, its bistability should be improved to obtain a good vitality of optical whiteness characteristic. The current study applies an integrated approach to find the optimal settings of important control factors to determine effectively the settings of various different design parameters, thereby meeting closely the bistability targets. An actual case study is used to demonstrate the usefulness of the suggested approach for improving the bistability characteristic of flexible displays. The optical whiteness ratio has been improved from 20.79 to 28.24. Also, the case company shortened the improvement schedule effectively, regained customer orders, and earned revenues of approximately USD 32,000,000.     

Organizational information security policies: a review and research framework

A major stream of research within the field of information systems security examines the use of organizational policies that specify how users of information and technology resources should behave in order to prevent, detect, and respond to security incidents. However, this growing (and at times, conflicting) body of research has made it challenging for researchers and practitioners to comprehend the current state of knowledge on the formation, implementation, and effectiveness of security policies in organizations. Accordingly, the purpose of this paper is to synthesize what we know and what remains to be learned about organizational information security policies, with an eye toward a holistic understanding of this research stream and the identification of promising paths for future study. We review 114 influential security policy-related journal articles and identify five core relationships examined in the literature. Based on these relationships, we outline a research framework that synthesizes the construct linkages within the current literature. Building on our analysis of these results, we identify a series of gaps and draw on additional theoretical perspectives to propose a revised framework that can be used as a basis for future research.     

The mild oxidation of three Tertiary lignites

Three Tertiary lignites have been oxidized with nitrobenzene and sodium hydroxide at 200 °C in a sealed tube. A scheme of extraction has been used to separate the oxidation products and the resulting solutions have been characterized by their infra-red and ultraviolet absorption spectra and by spot tests. The products contain phenolic hydroxyl and carbonyl — rather than carboxyl — groups. Some of the solutions have been reduced and their n.m.r. spectra recorded. The oxidation procedure shows promise as a method of determining the structure of lignites.     

Chemical and physical characteristics of phosphate rock materials of varying reactivity

Several chemical and physical properties of 10 phosphate rock (PR) materials of varying reactivity were evaluated. These included North Carolina phosphate rock (NCPR), Sechura phosphate rock (SPR), Chatham Rise phosphorite (CRP), Arad phosphate rock (APR), Gafsa phosphate rock (GPR), North Florida phosphate rock (NFPR), Jordanian phosphate rock (JPR), Mexican phosphate rock (MPR), Nauru Island phosphate rock (NIPR), and Makatea Island phosphate rock (MIPR). Concentrations of As and Cd were highest in NCPR and U was higher in APR and CRP than in the other reactive PR materials. Because Cd and U can accumulate in biological systems, it may be necessary to direct more attention towards the likely implications of Cd and U concentrations when evaluating a PR for direct application. Three sequential extractions with 2% citric acid may be more useful for comparing the chemical solubility of PR materials, particularly for those containing appreciable CaCO₃. For each particle-size fraction from <63 to >500 μm, SPR was more soluble in 2% citric acid than was NCPR. The higher solubility of SPR than NCPR in 2% citric acid, 2% formic acid, and neutral ammonium citrate possibly results from a higher chemical reactivity rather than from any difference in the surface area presented for dissolution. The poor relationship obtained between surface area and the solubility of the PR materials in the three chemical extractants suggests that surface area plays a secondary role to chemical reactivity in controlling the solubility of a PR in a chemical extractant. A Promesh plot provided an effective method for describing the particle-size characteristics of those PR materials which occurred as sands. Fundamental characteristics, such as mean particle size and uniformity, can readily be determined from a Promesh plot.     

Using HCA and TOPSIS approaches in personal digital assistant menu–icon interface design

Mobile electronic products have recently become very popular because of their portable convenience and versatile functions. The personal digital assistant (PDA) can even access the Internet. However, there is still plenty of room for improvement in the PDA interface. This research proposes a systematic approach to analyze, generate and evaluate a PDA integrated menu–icon interface design for the DigitHub Company based on customer requirements.Hierarchical clustering analysis (HCA) is incorporated with the analytic hierarchy process (AHP) to identify and categorize functional PDA menus and their corresponding icons. We evaluate the importance of each of the different functional menus and categories. We generate five PDA menu–icon interface design alternatives that meet the proposed design guidelines, and we evaluate each for their respective feasibilities. The technique for order preference by similarity to ideal solution (TOPSIS) method is applied to measure the overall operating performance of the five PDA menu–icon interface design alternatives. The evaluation results show that the preferred design is option PDA₅, a hierarchical and separated menu–icon layout style that features a two-layer menu structure.We expect that the proposed development procedure for the generation and evaluation of PDA menu–icon design alternatives based on customer requirements will be of interest to interface designers who wish to focus on mobile products.

Relevance to industry

This paper proposes an integrated procedure for designing PDA menu–icon interfaces. Our methodology should help in the creation and optimization of screen layouts for mobile phones, global positioning system (GPS) navigation devices, digital cameras and related screen interfaces.