Freeze-drying of low molecular weight poly(L-lactic acid) nanoparticles: effect of cryo- and lyoprotectants

The chemical and physical stability of polymeric nanoparticles is poor in aqueous suspensions, and the drying of these particles is often problematic. In the present study, the stability of freeze-dried low molecular weight poly(L-lactic acid) (PLA) nanoparticles was enhanced by adding glucose and/or lactose to the formulation as cryo- and lyoprotectants, respectively. Also the effect of an extra stabilizer, Tween 80, was studied. The best freeze-dried PLA nanoparticle formulations were achieved, when glucose and lactose were added in combination so that the amount of lactose was double the amount of glucose. With this combination the redispersion of high-quality nanoparticles (homogenous particle dispersion with original size and without aggregates) was achieved. The addition of Tween 80 further improved the quality of freeze-dried PLA nanoparticles by facilitating the redispersion of the lyophilized cake into optimal nanoparticles.     

Garbage‐Can Decision Making and the Accommodation of Uncertainty in New Drug Development Work

Innovation processes are sometimes described as a series of sequential activities, smoothly transforming into one another. However, in real‐life settings, innovation work is characterized by uncertainty, risk taking, politics and time pressure, and consequently much decision making in innovation work deviates from such rationalist models. Instead, decisions are made in the form of garbage‐can decision making, demonstrating a variety of non‐linear elements. Such characteristics are especially pronounced in industries based on science‐based innovation, operating under genuine uncertainty. This article reports a study of the clinical trial work in a major multinational pharmaceutical company and suggests that decision making includes at least four coping strategies for dealing with non‐linear and migrating decision‐making processes.     

Secondary school students’ collaboration during dyadic debates face-to-face and through computer chat

Communicative competence needed in today’s constructive learning environments both in virtual and physical classrooms requires most of all critical and argumentative thinking skills as well as abilities to use reciprocal and collaborative language. This study clarifies the quality of secondary school students’ collaboration in dyadic face-to-face and computer chat debates during argumentative discussions. The speech acts produced in 24 debates were first classified into either on-task or off-task categories. The on-task speech acts were then further classified into six collaborative and two non-collaborative categories. The students commonly presented questions and made requests for clarification or reactions as well as responded to issues put forward by their interlocutor. However, they seldom engaged in collaborative completion or recapitulated their arguments. The study suggests that while students appear to have the basic cognitive and social prerequisites for collaborative learning situations, in future they should be encouraged to collaboratively complete each others’ thoughts and recapitulate their own arguments.     

Core task analysis in accident investigation: analysis of maritime accidents in piloting situations

This article discusses the difficulties in utilising accident analysis as the basis for the development of complex socio-technical systems, and how to improve accident analysis to better meet such aims. It focuses on two themes: accident models and experts’ involvement in accident investigation. The article describes the development of a new core task analysis-based method for accident analysis. It also elaborates on the method by presenting summarising results of an investigation in which several maritime accidents were first analysed case-by-case, followed by a comparative analysis and a synthesis. The latter phases aimed at providing evident-based generic explanations for the accidents. The accidents occurred in Finnish coastal waters during sea or canal piloting between 1997 and 2000. The authors participated in both phases of the investigation for which the Finnish Accident Investigation Board was responsible. The presented method is argued to promote solutions to two current problems in accident investigation: generalisation from the results, and integration of the experts’ work.

Deformation due to mechanical and thermal sources in generalised orthorhombic thermoelastic material

A dynamical two-dimensional problem of thermoelasticity has been considered to investigate the disturbance due to mechanical (horizontal or vertical) and thermal source in a homogeneous, thermally conducting orthorhombic material. Laplace-Fourier transforms are applied to basic equations to form a vector matrix differential equation, which is then solved by eigenvalue approach. The displacements, stresses and temperature distribution so obtained in the physical domain are computed numerically and illustrated graphically. The numerical results of these quantities for zinc crystal-like material are illustrated to compare the results for different theories of generalised thermoelasticity for an insulated boundary and a temperature gradient boundary.     

Average complexity of backward q-gram string matching algorithms

Many efficient string matching algorithms make use of q-grams and process the text in windows which are read backward. In this paper we provide a framework for analyzing the average case complexity of these algorithms taking into account the statistical dependencies between overlapping q-grams. We apply this to the q-gram Boyer–Moore–Horspool algorithm adapted to various string matching problems and show that the algorithm is optimal on average.     

Effects of submerged macrophytes on sediment resuspension and internal phosphorus loading in Lake Hiidenvesi (southern Finland)

The effects of submerged macrophytes on sediment resuspension and internal phosphorus loading in the shallow Kirkkoj?rvi basin of Lake Hiidenvesi were studied by sedimentation traps and sediment and water samples. During the 83 d study period, 793 g DW m(-2) of sediment was resuspended within the stand formed by Ranunculus circinatus, Ceratophyllum demersum and Potamogeton obtusifolius. Outside the stand, 1701g DW m(-2) sediment resuspension was measured during the same period. Water turbidity and concentration of suspended solids (SS) were significantly lower within the plant bed compared with the surrounding water area. Despite the higher concentration of inorganic suspendoids, the concentration of chlorophyll a was higher in the open water than within the submerged plant bed, owing to the enhanced nutrient recycling rate in the absence of submerged plants. With the resuspended sediment, 11.8 mg Pm(-2)d(-1) was brought into the water column within the stand and 24.5 mg Pm(-2)d(-1) outside the stand. Within the macrophyte stand, resuspended particles absorbed phosphorus from the water (indicated by the inverse relationship between SS and soluble reactive phosphorus), which was probably connected to the lowered phosphorus concentration of surface sediment due to uptake by macrophytes.     

Control of Bacterial Diseases of Banana Using CRISPR/Cas-Based Gene Editing

Banana is an important staple food crop and a source of income for smallholder farmers in about 150 tropical and sub-tropical countries. Several bacterial diseases, such as banana Xanthomonas wilt (BXW), blood, and moko disease, cause substantial impacts on banana production. There is a vast yield gap in the production of bananas in regions where bacterial pathogens and several other pathogens and pests are present together in the same field. BXW disease caused by Xanthomonas campestris pv. musacearum is reported to be the most destructive banana disease in East Africa. The disease affects all the banana varieties grown in the region. Only the wild-type diploid banana, Musa balbisiana, is resistant to BXW disease. Developing disease-resistant varieties of bananas is one of the most effective strategies to manage diseases. Recent advances in CRISPR/Cas-based gene editing techniques can accelerate banana improvement. Some progress has been made to create resistance against bacterial pathogens using CRISPR/Cas9-mediated gene editing by knocking out the disease-causing susceptibility (S) genes or activating the expression of the plant defense genes. A synopsis of recent advancements and perspectives on the application of gene editing for the control of bacterial wilt diseases are presented in this article.     

Deformation due to Mechanical and Thermal Sources in a Thermoelastic Body with Voids under Axi-symmetric Distributions

The Laplace and Hankel transforms have been employed to find the general solution of a homogeneous, isotropic, thermoelastic half-space with voids for a plane axi-symmetric problem. The application of a thermoelastic half-space with voids subjected to a normal force and a thermal source acting at the origin has been considered to show the utility of the solution obtained. To obtain the solution in a physical form, a numerical inversion technique has been applied. The results in the form of displacements, stresses, temperature distribution, and change in volume fraction field are computed numerically and illustrated graphically for a magnesium crystal-like material to depict the effects of voids in the theory of coupled thermoelasticity (CT) and uncoupled thermoelasticity (UCT) for an insulated boundary and a temperature gradient boundary.