Early intestinal perforation secondary to congenital mesenteric defects

Gastrointestinal perforation (GIP) in preterm neonates may be idiopathic, due to necrotizing enterocolitis (NEC), or mechanical obstruction. The predominant cause of GIP in the neonatal period is NEC. Differential diagnosis with congenital malformations, including mesenteric defects leading to internal hernias, is mandatory if the onset is early. We describe two newborns with trans-mesenteric herniation resulting in GIP, and we discuss the presence of possible additional risk factors such as prematurity and predisposing vascular disruption in connective tissue disorders (Ehlers-Danlos syndrome), twinning, and use of assisted reproductive technologies. These cases prompted us to review our exploratory laparotomies performed for intestinal obstruction, complicated/or not with perforation, to identify the frequency of neonatal trans-mesenteric hernias in a referral hospital. The prevalence of GIP and of internal hernia was 25% and 3.3%, respectively. In conclusion, time-onset and particular conditions associated with GIP should lead to a high index of suspicion for internal hernias in order to achieve appropriate diagnosis and therapy

Patch occupancy of stream fauna across a land cover gradient in the southern Appalachians, USA

We modeled patch occupancy to examine factors that best predicted the prevalence of four functionally important focal stream consumers (Tallaperla spp., Cambarus spp., Pleurocera proxima, and Cottus bairdi) among 37 reaches within the Little Tennessee River basin of the southern Appalachian Mountains, USA. We compared 34 models of patch occupancy to examine the association of catchment and reach scale factors that varied as a result of converting forest to agricultural or urban land use. Occupancy of our taxa was linked to parameters reflecting both catchment and reach extent characteristics. At the catchment level, forest cover or its conversion to agriculture was a major determinant of occupancy for all four taxa. Patch occupancies of Tallaperla, Cambarus, and C. bairdi were positively, and Pleurocera negatively, correlated with forest cover. Secondarily at the reach level, local availability of large woody debris was important for Cambarus, availability of large cobble substrate was important for C. bairdi, and stream calcium concentration was important for P. proxima. Our results show the abundance of stream organisms was determined by the taxon-dependent interplay between catchment- and reach-level factors.Keywords: Patch occupancy, Stream chemistry, Appalachians, Consumers, Land us

An Integrated Microfluidic Device for Monitoring Changes in Nitric Oxide Production in Single T-Lymphocyte (Jurkat) Cells

A considerable amount of attention has been focused on the analysis of single cells in an effort to better understand cell heterogeneity in cancer and neurodegenerative diseases. Although microfluidic devices have several advantages for single cell analysis, few papers have actually demonstrated the ability of these devices to monitor chemical changes in perturbed biological systems. In this paper, a new microfluidic channel manifold is described that integrates cell transport, lysis, injection, electrophoretic separation, and fluorescence detection into a single device, making it possible to analyze individual cells at a rate of 10 cells/min in an automated fashion. The system was employed to measure nitric oxide (NO) production in single T-lymphocytes (Jurkat cells) using a fluorescent marker, 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA). The cells were also labeled with 6-carboxyfluorescein diacetate (6-CFDA) as an internal standard. The NO production by control cells was compared to that of cells stimulated using lipopolysaccharide (LPS), which is known to cause the expression of inducible nitric oxide synthase (iNOS) in immune-type cells. Statistical analysis of the resulting electropherograms from a population of cells indicated a twofold increase in NO production in the induced cells. These results compare nicely to a recently published bulk cell analysis of NO

The haptic perception of spatial orientations

This review examines the isotropy of the perception of spatial orientations in the haptic system. It shows the existence of an oblique effect (i.e., a better perception of vertical and horizontal orientations than oblique orientations) in a spatial plane intrinsic to the haptic system, determined by the gravitational cues and the cognitive resources and defined in a subjective frame of reference. Similar results are observed from infancy to adulthood. In 3D space, the haptic processing of orientations is also anisotropic and seems to use both egocentric and allocentric cues. Taken together, these results revealed that the haptic oblique effect occurs when the sensory motor traces associated with exploratory movement are represented more abstractly at a cognitive level

Context-dependent responses to light contribute to salamander responses to landscape disturbances

Behaviour often regulates population responses to environmental change, but linking behavioural responses to population patterns can be challenging because behavioural responses are often context-dependent, have an instinctive component, and yet may be modified by experience. Black-bellied salamanders (Desmognathus quadramaculatus, Holbrook 1840) occupy forested streams where dense canopies create cool, dark environments. Because riparian deforestation negatively affects salamander population connectivity yet some individuals choose to persist in these gaps, we sought to evaluate whether phototaxis could explain these patterns and whether phototactic behaviour would be influenced by experience (capture from forested or deforested areas) or context (refuge type and availability). Our results demonstrated that D. quadramaculatus larvae exhibited negative phototaxis but that larvae from forested streams exhibited stronger negative phototaxis than individuals from deforested streams. Larvae also selected habitat closer to light when refuge was available. Our results show that light alters larval D. quadramaculatus habitat use, but the magnitude of that effect depends on refuge availability and experience with well-lit conditions associated with forest removal. As human activities reduce canopy cover and refuge availability, negative phototaxis may be one explanation for behavioural barriers to movement. Ultimately, the ability of salamanders to exhibit behavioural plasticity will determine their potential for local adaptation facilitating persistence in the face of environmental change.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Wikis in the classroom: Properties and potential uses of this collaborative learning tool

Background/Question/Methods 
Student engagement is tied to course performance and information retention. Shifting the focus of the classroom from a lecture-based approach to a student-centered learning environment is one way to achieve this goal. One tool that can be used to allow student contribution to the content and direction of a course is a wiki. Wikis are highly flexible collaborative websites that can be structured to meet course needs and allow multiple users to contribute to site content. They provide a platform where real-time editing can be performed in a flexible 'topical' format. They are intended to promote group learning through collaboration rather than isolated reflection, and can provide another avenue through which instructors can connect with various types of learners through multimedia learning. 

Results/Conclusions 
We will present multiple ways in which wikis can be used in the classroom, such as collaborative projects, peer review, debates, competitions, and student comments and reflections on course material. Within these contexts faculty can promote the use of multimedia and creativity within student work and enable peer learning through public project viewing. They also track each student’s edits and additions to site content, allowing for instructor assessment of an individual’s contributions to group progress. We have found that the use of the wiki format promoted class participation, a sense of community within the course in question, and a feeling of project ownership and accomplishment

Adding steam to control dust in mineral processing /

Includes bibliographical references.Mode of access: Internet

Use of foam for dust control in minerals processing /

Includes bibliographical references.Mode of access: Internet

The Effects of Moisture on LiD Single Crystals Studied by Temperature Programmed Reaction

Temperature programmed reaction (TPR) technique was performed on LiOH powders and LiD single crystals previously exposed to different moisture levels. Our results show that the LiOH decomposition process has an activation energy barrier of 30 to 33.1 kcal/mol. The LiOH structure is stable even if kept at 320 K for 100 years. However, LiOH structures formed on the surface of LiD during moisture exposure at low dosages may have multiple activation energy barriers, some of which may be much lower than 30 kcal/mol. We attribute the lowering of the activation energy barrier for the LiOH decomposition to the existence of dangling bonds, cracks, and other long range disorders in the LiOH structures formed at low levels of moisture exposure. These defective LiOH structures may decompose significantly over the next 100 years of storage even at room temperature. At high moisture exposure levels, LiOH.H{sub 2}O formation is observed. The release of H{sub 2}O molecules from LiOH.H{sub 2}O structure has small activation energy barriers in the range of 13.8 kcal/mol to 16.0 kcal/mol. The loosely bonded H{sub 2}O molecules in the LiOH.H{sub 2}O structure can be easily pumped away at room temperature in a reasonable amount of time. Our experiments also suggest that handling LiD single crystals at an elevated temperature of 340 K or more reduces the growth rate of LiOH and LiOH.H{sub 2}O significantly. Therefore, a proposed way of minimizing hydrogen formation (due to H{sub 2}O reaction with LiD) in a closed system containing LiOH in the presence of LiD may be to handle LiD at a slightly, elevated temperature during the assembly