Cryoultramicrotomy versus plastic embedding: comparative immunocytochemistry of rat anterior pituitary cells

The anterior pituitary of the rat is used as a model for the study of the effects of freezing or plastic embedding on the maintenance of antigenicity. Rat anterior pituitaries are fixed in 2.5% glutaraldehyde in 0.1 m phosphate buffer pH 7.4. Some of the blocks are post-fixed before being divided into two lots. One batch is frozen, while the other is dehydrated and embedded. The indirect antibody enzyme method is applied to ultrathin sections obtained by cryoultramicrotomy after freezing or by sectioning after embedding. All six pituitary hormones are detected by both methods. Comparison shows that the morphological characteristics are identical for both techniques, though ultrastructural preservation is better after embedding. Immunoreactivity is found in secretory granules and sometimes in the endoplasmic reticulum. Osmium postfixation may reduce or even abolish antigenicity in plastic-embedded tissue. After cryoultramicrotomy, however, even after osmium fixation, antibody may be used 1000 times more diluted than after plastic embedding. Embedding preserves ultrastructure and limited antigenicity while the use of cryoultramicrotomy is a far more sensitive technique.     

A large neighbourhood search heuristic for ship routing and scheduling with split loads

The purpose of this paper is to present and solve a new, important planning problem faced by many shipping companies dealing with the transport of bulk products. These shipping companies are committed to carrying some contract cargoes and will try to derive additional revenue from optional spot cargoes. In most of the literature on ship routing and scheduling problems a cargo cannot be transported by more than one ship. By introducing split loads this restriction is removed and each cargo can be transported by several ships. In this paper we propose a large neighbourhood search heuristic for the ship routing and scheduling problem with split loads. Computational results show that the heuristic provides good solutions to real-life instances within reasonable time. It is also shown that introducing split loads can yield significant improvements.     

A new safety device for hemodialysis

Accidental venous needle dislodgement during hemodialysis may cause serious bleeding including a sometimes fatal outcome. The venous pressure gauge of the dialysis monitor does not react when dislodgement occurs. A sensor patch put as an adhesive over the venous needle puncture site connected to an alarm unit by an optic fiber has been clinically tested in 5 dialysis departments. A small amount of blood on the sensor activates a light and sound alarm. A simple questionnaire was filled out by the nurses at each dialysis concerning their feeling of safety when the new device was used. Forty-one patients, mean age 65 years, have tested the new safety device. Two hundred test dialyses were studied, after exclusion of 13 tests. One hundred seventy-nine tests reacted positively on blood. In another 6 dialyses, a warning light appeared on the alarm unit indicating a failure in the sensor patch. Thus, the alarm functioned in 92.5% of all tests. After a small modification of the sensor patches there were only 2 dialyses (2/71) without an activated alarm on blood, i.e., 97.2% positive alarm reactions. The answers of the nurses indicated that they had an increased feeling of safety when using the new safety device, with a mean value of 3.4 points on a visual scale from 0 to 5 where 5 meant very much increased safety. In a situation when the dialysis monitors today do not react on bleedings from venous needle dislodgements, the new alarm safety device fulfils a known shortage in routine dialysis safety. In situations where supervision during a dialysis session may be insufficient as, for example, in home hemodialysis and self-care dialysis or in other situations when the patient is sleeping, the device may be life saving.     

Effects of Light and Nutrient Availability on Aspen: Growth, Phytochemistry, and Insect Performance

This study explored the effect of resource availability on plant phytochemical composition within the framework of carbon–nutrient balance (CNB) theory. We grew quaking aspen (Populus tremuloides) under two levels of light and three levels of nutrient availability and measured photosynthesis, productivity, and foliar chemistry [water, total nonstructural carbohydrates (TNC), condensed tannins, and phenolic glycosides]. Gypsy moths (Lymantria dispar) and forest tent caterpillars (Malacosoma disstria) were reared on foliage from each of the treatments to determine effects on insect performance. Photosynthetic rates increased under high light, but were not influenced by nutrient availability. Tree growth increased in response to both the direct and interactive effects of light and nutrient availability. Increasing light reduced foliar nitrogen, while increasing nutrient availability increased foliar nitrogen. TNC levels were elevated under high light conditions, but were not influenced by nutrient availability. Starch and condensed tannins responded to changes in resource availability in a manner consistent with CNB theory; levels were highest under conditions where tree growth was limited more than photosynthesis (i.e., high light–low nutrient availability). Concentrations of phenolic glycosides, however, were only moderately influenced by resource availability. In general, insect performance varied relatively little among treatments. Both species performed most poorly on the high light–low nutrient availability treatment. Because phenolic glycosides are the primary factor determining aspen quality for these insects, and because levels of these compounds were minimally affected by the treatments, the limited response of the insects was not surprising. Thus, the ability of CNB theory to accurately predict allocation to defense compounds depends on the response of specific allelochemicals to changes in resource availability. Moreover, whether allelochemicals serve to defend the plant depends on the response of insects to specific allelochemicals. Finally, in contrast to predictions of CNB theory, we found substantial allocation to storage and defense compounds under conditions in which growth was carbon-limited (e.g., low light), suggesting a cost to defense in terms of reduced growth.     

Harvesting Robots for High‐value Crops: State‐of‐the‐art Review and Challenges Ahead

This review article analyzes state‐of‐the‐art and future perspectives for harvesting robots in high‐value crops. The objectives were to characterize the crop environment relevant for robotic harvesting, to perform a literature review on the state‐of‐the‐art of harvesting robots using quantitative measures, and to reflect on the crop environment and literature review to formulate challenges and directions for future research and development. Harvesting robots were reviewed regarding the crop harvested in a production environment, performance indicators, design process techniques used, hardware design decisions, and algorithm characteristics. On average, localization success was 85%, detachment success was 75%, harvest success was 66%, fruit damage was 5%, peduncle damage was 45%, and cycle time was 33 s. A kiwi harvesting robot achieved the shortest cycle time of 1 s. Moreover, the performance of harvesting robots did not improve in the past three decades, and none of these 50 robots was commercialized. Four future challenges with R&D directions were identified to realize a positive trend in performance and to successfully implement harvesting robots in practice: (1) simplifying the task, (2) enhancing the robot, (3) defining requirements and measuring performance, and (4) considering additional requirements for successful implementation. This review article may provide new directions for future automation projects in high‐value crops.     

An Experimental Toolbox for Structure-Based Hit Discovery for P. aeruginosa FabF,a Promising Target for Antibiotics

FabF (3-oxoacyl-[acyl-carrier-protein] synthase 2), which catalyses the rate limiting condensation reaction in the fatty acid synthesis II pathway, is an attractive target for new antibiotics. Here, we focus on FabF from P. aeruginosa (PaFabF) as antibiotics against this pathogen are urgently needed. To facilitate exploration of this target we have set up an experimental toolbox consisting of binding assays using bio-layer interferometry (BLI) as well as saturation transfer difference (STD) and WaterLOGSY NMR in addition to robust conditions for structure determination. The suitability of the toolbox to support structure-based design of FabF inhibitors was demonstrated through the validation of hits obtained from virtual screening. Screening a library of almost 5 million compounds resulted in 6 compounds for which binding into the malonyl-binding site of FabF was shown. For one of the hits, the crystal structure in complex with PaFabF was determined. Based on the obtained binding mode, analogues were designed and synthesised, but affinity could not be improved. This work has laid the foundation for structure-based exploration of PaFabF.     

Extraction of Spent Bleaching Earth in the Production of Renewable Diesel

The extraction of oils based on animal fat and vegetable oil from two types of spent bleaching earths, namely from the acidic sepiolite and the nonacidic palygorskite, was investigated by the Soxhlet method with hexane as a solvent. The yields of oil were independent of the feedstock, whereas a much lower oil yield was obtained with palygorskite exhibiting also a smaller surface area as compared to sepiolite which provided a higher yield. The glyceride compositions were very similar in bleached and extracted oils, while slightly lower melting and crystallization energies were determined by differential scanning calorimetry for the extracted oils bleached with acidic clay indicating minor hydrolysis of triglycerides.     

A thermodynamic analysis of the chromium-nitrogen system

An attempt is made to rationalize and bring into mutual agreement different types of information on the phase equilibria in the Cr-N system by applying simple thermodynamic models to the individual phases. As a result, equations and curves describing the various phase equilibria are recommended.     

A thermodynamic analysis of the iron-nitrogen system

An attempt is made to rationalize and bring into mutual agreement different types of information on the phase equilibria in the Fe-N system by applying simple thermodynamic models to the individual phases. The attempt was successful except for some information regarding the ∈ phase. As a result, equations and curves describing the various phase equilibria are recommended.