Directed Fiber Outgrowth from Transplanted Embryonic Cortex-Derived Neurospheres in the Adult Mouse Brain

Neural transplantation has emerged as an attractive strategy for the replacement of neurons that have been lost in the central nervous system. Multipotent neural progenitor cells are potentially useful as donor cells to repopulate the degenerated regions. One important aspect of a transplantation strategy is whether transplanted cells are capable of fiber outgrowth with the aim of rebuilding axonal connections within the host brain. To address this issue, we expanded neuronal progenitor from the cortex of embryonic day 15 ubiquitously green fluorescent protein-expressing transgenic mice as neurospheres in vitro and grafted them into the entorhinal cortex of 8-week-old mice immediately after a perforant pathway lesion. After transplantation into a host brain with a lesion of the entorhino-hippocampal projection, the neurosphere-derived cells extended long fiber projections directed towards the dentate gyrus. Our results indicate that transplantation of neurosphere-derived cells might be a promising strategy to replace lost or damaged axonal projections

mrstudyr: Retrospectively Studying the Effectiveness of Mutant Reduction Techniques

Mutation testing is a well-known method for measuring a test suite’s quality. However, due to its computational expense and intrinsic difficulties (e.g., detecting equivalent mutants and potentially checking a mutant’s status for each test), mutation testing is often challenging to practically use. To control the computational cost of mutation testing, many reduction strategies have been proposed (e.g., uniform random sampling over mutants). Yet, a stand-alone tool to compare the efficiency and effectiveness of these methods is heretofore unavailable. Since existing mutation testing tools are often complex and languagedependent, this paper presents a tool, called mrstudyr, that enables the “retrospective” study of mutant reduction methods using the data collected from a prior analysis of all mutants. Focusing on the mutation operators and the mutants that they produce, the presented tool allows developers to prototype and evaluate mutant reducers without being burdened by the implementation details of mutation testing tools. Along with describing mrstudyr’s design and overviewing the experimental results from using it, this paper inaugurates the public release of this open-source tool

Automated Layout Failure Detection for Responsive Web Pages Without an Explicit Oracle

As the number and variety of devices being used to access the World Wide Web grows exponentially, ensuring the correct presentation of a web page, regardless of the device used to browse it, is an important and challenging task. When developers adopt responsive web design (RWD) techniques, web pages modify their appearance to accommodate a device’s display constraints. However, a current lack of automated support means that presentation failures may go undetected in a page’s layout when rendered for different viewport sizes. A central problem is the difficulty in providing an automated “oracle” to validate RWD layouts against, meaning that checking for failures is largely a manual process in practice, which results in layout failures in many live responsive web sites. This paper presents an automated failure detection technique that checks the consistency of a responsive page’s layout across a range of viewport widths, obviating the need for an explicit oracle. In an empirical study, this method found failures in 16 of 26 real-world production pages studied, detecting 33 distinct failures in total

Virtual Mutation Analysis of Relational Database Schemas

Relational databases are a vital component of many modern soft- ware applications. Key to the definition of the database schema — which specifies what types of data will be stored in the database and the structure in which the data is to be organized — are integrity constraints. Integrity constraints are conditions that protect and preserve the consistency and validity of data in the database, preventing data values that violate their rules from being admitted into database tables. They encode logic about the application concerned, and like any other component of a software application, need to be properly tested. Mutation analysis is a technique that has been successfully applied to integrity constraint testing, seeding database schema faults of both omission and commission. Yet, as for traditional mutation analysis for program testing, it is costly to perform, since the test suite under analysis needs to be run against each individual mutant to establish whether or not it exposes the fault. One overhead incurred by database schema mutation is the cost of communicating with the database management system (DBMS). In this paper, we seek to eliminate this cost by performing mutation analysis virtually on a local model of the DBMS, rather than on an actual, running instance hosting a real database. We present an empirical evaluation of our virtual technique revealing that, across all of the studied DBMSs and schemas, the virtual method yields an average time saving of 51% over the baseline

Hitchhikers Need Free Vehicles! Shared Repositories for Statistical Analysis in SBST

As a means for improving the maturity of the data analysis methods used in the search-based software testing field, this paper presents the need for shared repositories of well-documented statistical analysis code and replication data. In addition to explaining the benefits associated with using these repositories, the paper gives suggestions (e.g., the testing of analysis code) for improving the study of data arising from experiments with randomized algorithms

Molecular mechanisms separating two axonal pathways during embryonic development of the avian optic tectum

During embryonic development of the avian optic tectum, retinal and tectobulbar axons form an orthogonal array of nerve processes. Growing axons of both tracts are transiently very closely apposed to each other. Despite this spatial proximity, axons from the two pathways do not intermix, but instead restrict their growth to defined areas, thus forming two separate plexiform layers, the stratum opticum and the stratum album centrale. In this study we present experimental evidence indicating that the following three mechanisms might play a role in segregating both axonal populations: Retinal and tectobulbar axons differ in their ability to use the extracellular matrix protein laminin as a substrate for axonal elongation; the environment in the optic tectum is generally permissive for retinal axons, but is specifically nonpermissive for tectobulbar axons, resulting in a strong fasciculation of the latter; and growth cones of temporal retinal axons are reversibly inhibited in their motility by direct contact with the tectobulbar axon's membrane

Psychiatric and psychosocial outcome of orthotopic liver transplantation

Background. The study aimed to explore the prevalence of psychiatric disorders among orthotopic liver transplantation (OLT) recipients, and to investigate how psychiatric morbidity was linked to health-related quality of life (HRQOL). Methods: We recruited 75 patients who had undergone OLT a median of 3.8 years previously (range = 5-129 months). Psychiatric morbidity was assessed using the Structural Clinical Interview for the IDSM-III-R. Psychometric observer-rating and self-rating scales were administered to evaluate cognitive functioning (SKT), depressive symptomatology (HAMD(17)), Posttraumatic stress symptoms (PTSS-10), social support (SSS), and HRQOL (SF-36 Health Status Questionnaire). Treatment characteristics were obtained from medical records. Results: 22.7% (n = 17) of our sample had a current or probable psychiatric diagnosis according to DSM-III-R: 2.7% full posttraumatic stress disorder (PTSD) (n = 2), 2.7% major depressive disorder (MDD) comorbid to full PTSD (n = 2), 1.3% MDD comorbid to partial PTSD (n = 1), and 16% partial PTSD (n = 12). Patients with PTSD symptoms demonstrated lower cognitive performance, higher severity of depressive symptoms and more unfavorable perception of social support. OLT-related PTSD symptomatology was associated with maximal decrements in HRQOL. The duration of intensive care treatment, the number of medical complications, and the occurrence of acute rejection were positively correlated with the risk of PTSD symptoms subsequent to OLT. Conclusion: OLT-related PTSD symptomatology impairing HRQOL is a complication for a subgroup of OLT recipients. Health-care providers should be aware of the possible presence of PTSD in OLT survivors. Copyright (C) 2002 S. KargerAG, Basel

Automated Search for Good Coverage Criteria: Moving from Code Coverage to Fault Coverage Through Search-Based Software Engineering

We propose to use Search-Based Software Engineering to automatically evolve coverage criteria that are well correlated with fault revelation, through the use of existing fault databases. We explain how problems of bloat and overfitting can be ameliorated in our approach, and show how this new method will yield insight into faults — as well as better guidance for Search-Based Software Testing

Testing in resource constrained execution environments

Software for resource constrained embedded devices is often implemented in the Java programming language because the Java compiler and virtual machine provide enhanced safety, portability, and the potential for run-time optimization. It is important to verify that a software application executes correctly in the environment in which it will normally execute, even if this environment is an embedded one that severely constrains memory resources. Testing can be used to isolate defects within and establish a confidence in the correctness of a Java application that executes in a resource constrained environment. However, executing test suites with a Java virtual machine (JVM) that uses dynamic compilation to create native code bodies can introduce significant testing time overheads if memory resources are highly constrained. This paper describes an approach that uses adaptive code unloading to ensure that it is feasible to perform testing in the actual memory constrained execution environment. The experiments demonstrate that code unloading can reduce both the test suite execution time by 34 % and the code size of the test suite and application under test by 78 % while maintaining the overall size of the JVM. Categories and Subject Descriptors: D.2.5 [Software Engineering]: Testing and Debugging-Testing tools; D.3.4 [Programming Languages]: Processors-code generation