Foxe3 is required for morphogenesis and differentiation of the anterior segment of the eye and is sensitive to Pax6 gene dosage

AbstractThe dysgenetic lens (dyl) mouse mutant has mutations in Foxe3, which inactivate DNA binding by the encoded forkhead transcription factor. Here we confirm, by targeted inactivation, that Foxe3 mutations are responsible for the dyl phenotype, which include loss of lens epithelium; a small, cataractic lens; and failure of the lens to detach from the surface ectoderm. In contrast to a recent report of targeted Foxe3, we found no phenotypic difference between dyl and Foxe3−/− mutants when congenic strains were compared, and thus nothing that argues against Foxe3dyl being a null allele. In addition to the lens, most tissues of the anterior segment–iris, cornea, ciliary body and trabecular meshwork–are malformed or show differentiation defects. Many of these abnormalities, such as irido-corneal and irido-lenticular adherences, are present in a less severe form in mice heterozygous for the Foxe3 mutation, in spite of these having an intact lens epithelium. Early Foxe3 expression is highly sensitive to a halved Pax6 gene dosage and there is a striking phenotypic similarity between Pax6 and Foxe3 mutants. We therefore propose that many of the ocular malformations associated with Pax6 haploinsufficiency are consequences of a reduced expression of Foxe3

To what extent does surrounding landscape explain stand-level occurrence of conservation-relevant species in fragmented boreal and hemi-boreal forest?-a systematic review protocol

Background: Silviculture and land-use change has reduced the amount of natural forest worldwide and left what remains confined to isolated fragments or stands. To understand processes governing species occurrence in such stands, much attention has been given to stand-level factors such as size, structure, and deadwood amount. However, the surrounding matrix will directly impact species dispersal and persistence, and the link between the surrounding landscape configuration, composition and history, and stand-level species occurrence has received insufficient attention. Thus, to facilitate optimisation of forest management and species conservation, we propose a review addressing 'To what extent does surrounding landscape explain stand-level occurrence of conservation-relevant species in fragmented boreal and hemi-boreal forest?'.Methods: The proposed systematic review will identify and synthesise relevant articles following the CEE guidelines for evidence synthesis and the ROSES standards. A search for peer-reviewed and grey literature will be conducted using four databases, two online search engines, and 36 specialist websites. Identified articles will be screened for eligibility in a two-step process; first on title and abstract, and second on the full text. Screening will be based on predefined eligibility criteria related to a PECO-model; population being boreal and hemi-boreal forest, exposure being fragmentation, comparator being landscapes with alternative composition, configuration, or history, and outcome being occurrence (i.e., presence and/or abundance) of conservation-relevant species. All articles that pass the full-text screening will go through study validity assessment and data extraction, and be part of a narrative review. If enough studies prove comparable, quantitative meta-analyses will also be performed. The objective of the narrative review and the meta-analyses will be to address the primary question as well as six secondary questions, and to identify important knowledge gaps

Mass transfer of calcium across the peritoneum at three different peritoneal dialysis fluid Ca2+ and glucose concentrations.

Mass transfer of calcium across the peritoneum at three different peritoneal dialysis fluid Ca2+ and glucose concentrations.BackgroundIn peritoneal dialysis, the rate of ultrafiltration has been predicted to be a major determinant of peritoneal calcium (Ca2+) removal. Hence, dialysis fluid glucose concentration should be an important factor governing the transperitoneal Ca2+ balance. The aim of this study was to test the effect of various dialysate glucose levels and selected dialysate Ca2+ levels on Ca2+ removal in peritoneal dialysis patients.MethodsPatients (N = 8) received, during a 7-week period, 2L of lactate (30mmol/L)/bicarbonate (10mmol/L)–buffered peritoneal dialysis solutions containing either 1.5% glucose and 1.0mmol/L Ca2+ or 2.5% glucose and 1.6mmol/L Ca2+, or 4% glucose and 2.5mmol/L Ca2+, respectively, provided in a three-compartment bag (trio system). Patients underwent standardized (4-hour) dwells, one for each of the three dialysates to assess permeability-surface area product (PS) or mass transfer area coefficients (MTAC) for ionized and “freely diffusible” Ca2+, lactate, glucose, bicarbonate, phosphate, creatinine, and urea.ResultsThere was a clear-cut dependence of peritoneal Ca2+ removal on the rate of ultrafiltration. For large peritoneal to dialysate Ca2+ gradients (2.5mmol/L Ca2+ in 4% glucose) a close fit of measured to simulated data was predicted by the three-pore model using nonelectrolyte equations. For low transperitoneal Ca2+ concentration gradients, however, directly measured Ca2+ data agreed with the simulated ones only when the peritoneal Ca2+ PS was set lower than predicted from pore theory (6mL/min).ConclusionThere was a marked ultrafiltration dependence of transperitoneal Ca2+ transport. Nonelectrolyte equations could be used to simulate peritoneal ion (Ca2+) transport provided that the transperitoneal ion concentration gradients were large. Based on our data 1.38mmol/L Ca2+ in the dialysis fluid would have created zero net Ca2+ gain during a 4-hour dwell for 1.5% glucose, whereas 1.7 and 2.2mmol/L Ca2+ would have been needed to produce zero Ca2+ gain for 2.5% glucose and 3.9% glucose, respectively

Survey of Design Methods and Material Characteristics in Rubber Engineering

The unique properties of elastomeric materials are taken advantage of in many engineering applications. Elastomeric units are used as couplings or mountings between stiff structures. Examples of these are shock absorbers, vibration insulators, flexible joints, seals and suspensions.The development of computers and of analysis programs in this area has given engineers a new tool for the design of elastomeric components. Computer simulation by finite element analysis has become increasingly important, allowing the mechanical behavior of products with for complex geometries, as well as loading cases of different kinds to be evaluated. Computer simulations enable both static and dynamic aspects to be analyzed. These matters have been recognized by the manufacturers of rubber products and by their customers. The benefits are shorter time for product development and also quality improvements.However, the possibilities available for finding less complicated technical solutions at lower cost with the use of elastomers, has not been fully utilized. Rubber components could be employed more frequently in design if engineers were more familiar with materials of this sort.Part of the problem lies in education and in the dissemination of information. Engineers working in the design area tend to not be very familiar with elastomeric materials and their properties. The offerings of courses on the mechanics of polymers at schools and universities are very limited. Skillful engineers in this field have usually acquired their knowledge through many years of experience and not formal education.Moreover, the complicated nature of the material behavior involved makes it difficult to devise general design rules and design tools. Only recently have computers and analysis programs become powerful enough for the analysis of nonlinear elastic problems involving large strains.It is essential, if one is to become competitive in high-tech applications, to possess a thorough knowledge of computer methods, material models and test methods available.There has likewise been a lack of relevant data for the computer analysis of elastomeric materials. The design tools employed rely on the material models available and on the test data required for the calibration of these models. In many cases, the only information available for analysis is a value for the hardness of the rubber in question. The wide variety of rubber compounds is also a problem. The characterization of different materials is costly and time-consuming. There is thus a need for simple and reliable methods to characterize the different vulcanizates

Servicelinje eller flextrafik – när, var, hur?

Trafikforskningen vid Lunds Tekniska Högskola (LTH) har länge hävdat att det krävs mellanformer, mellan den ordinarie linjetrafiken och den speciella trafikform som anges i den svenska lagstiftningen om färdtjänst, utförd med specialfordon eller taxi. Under snart två decennier har dessa mellanformer i Sverige i huvudsak utformats som s k servicelinjer med god yttäckning genom en slingrande linjeföring. Korta gångavstånd prioriteras före snabbhet och förarna instrueras att ta god tid på sig så att resenärerna i den aktuella målgruppen kan känna sig trygga och väl omhändertagna. Fordonen har låga golv, är små och erbjuder närhet med föraren

Kinetics of oxidation of nm-sized soot spherules

We analyse the non-catalytic soot oxidation kinetics predicted by four models implying, respectively, (i) monosized uniform sphericallyshaped soot spherules, (ii) monosized disk-like spherules formed of carbon sheets, (iii) spherically shaped spherules with a realisticsize distribution, and (iv) disk-like spherules with a realistic size distribution. In all the cases, the reaction front is considered to movefrom the periphery to the center. The effect of the spherule size distribution on the oxidation kinetics is found to be appreciable andaccordingly should be taken into account in interpretations of the corresponding experiments. The latter is illustrated by scrutinizingrelevant experimental data and illustrating that model (iv) appears to be preferable

Kinetics of oxidation of nm-sized soot spherules

We analyse the non-catalytic soot oxidation kinetics predicted by four models implying, respectively, (i) monosized uniform sphericallyshaped soot spherules, (ii) monosized disk-like spherules formed of carbon sheets, (iii) spherically shaped spherules with a realisticsize distribution, and (iv) disk-like spherules with a realistic size distribution. In all the cases, the reaction front is considered to movefrom the periphery to the center. The effect of the spherule size distribution on the oxidation kinetics is found to be appreciable andaccordingly should be taken into account in interpretations of the corresponding experiments. The latter is illustrated by scrutinizingrelevant experimental data and illustrating that model (iv) appears to be preferable