Hypertext — a Bibliometric Briefing

Students' opinions about the degree of impact, status, and socio-cognitive viability with the utilization of the emerging three-dimensional (3D) computer-generated technologies may vary. Indisputably, 3D technology-enhanced environments have provided considerable benefits and affordances to the contemporary e-Education. In these circumstances, virtual worlds (VWs) like second life (SL) have generally intensified with an extensive perpetuation and penetration of innovative performances that encapsulated or enacted from the vast majority of higher education fields. At the same time, there is growing widespread recognition of reasons affecting the high or low degree of students' engagement in online and blended course delivery methods held in 3D VWs. Notwithstanding that most notable studies have disclosed SL functional capabilities from a plethora of pilot case studies, however, it is still lacking an experiential-based research approach to determine the degree of students' engagement in blended and online courses at university level through SL. The present comparative study explores students' engagement overall as a multidimensional construct consisting of emotional, behavioral, and cognitive factors. One hundred and thirty-five undergraduate and postgraduate students in almost identical blended and online instructional conditions held in SL took part in this project. Preliminary results have decoded students' satisfaction for both methods, despite the fact that the voluntary sample composed of different educational disciplines. The quantitative analysis showed that postgraduate students of the online course had more positive results and the degree of engagement significantly increased compared to those who enrolled with the blended course delivery method. The instructional affordances from the utilization of SL were the collaborative climate between users (instructor and students) who eliminated various intractable boundaries which were predominantly observed by several conventional methods. Specifically it was revealed that the online course delivery method engaged more students with the collaborative activities. Educational implications and recommendations for future research are also included.     

Electrostatic force calculation for an EWOD-actuated droplet

This paper examines the electrostatic force on a microdroplet transported via electrowetting on dielectric (EWOD). In contrast with previous publications, this article details the force distribution on the advancing and receding fluid faces, in addition to presenting simple algebraic formulae for the net force in terms of system parameters. Dependence of the force distribution and its integral on system geometry, droplet location, and material properties is described. The consequences of these theoretically and numerically obtained results for design and fabrication of EWOD devices are considered.     

Neurologic findings in coronary artery bypass patients: perioperative or preexisting?

OBJECTIVES/DESIGN: This prospective study compares the incidence of preexisting neurologic findings in elective cardiac surgery patients presenting with and without coronary atherosclerosis. SETTING: This single-center study was conducted at a tertiary care hospital. PARTICIPANTS/INTERVENTIONS: After Review Board approval and obtaining written informed consent, 11 patients undergoing valvular heart surgery, 9 patients undergoing similar valvular procedures with concomitant coronary artery bypass surgery, and 4 patients undergoing coronary artery bypass surgery alone were enrolled. Preoperatively, all patients underwent a structured neurologic assessment, and the latter four additionally had preoperative magnetic resonance imaging. MEASUREMENTS AND MAIN RESULTS: The patients, 9 of 24 of whom were female, were aged 46 to 78 years and, other than ischemic heart disease, had medical histories that were similar between groups, with the exception of one patient having scleroderma. None of the patients had a clinical history of neurologic or cerebrovascular disease. Nine percent (1 of 11) of the valve-only patients showed subtle preoperative neurologic abnormalities, compared with 89% (eight of nine) of the valve patients having concomitant coronary surgery and 100% (four of four) of coronary artery bypass-only patients. Additionally, brain imaging scans of all four coronary bypass patients showed nonspecific changes reported as scattered punctate areas of high signal less than 3 to 4 mm in diameter. CONCLUSION: This survey shows that both subtle neurological abnormalities and magnetic resonance imaging lesions can be found in a high percentage of patients with coronary atherosclerosis. Furthermore, this study indicates that without a standardized preoperative neurological examination, postoperative neurologic dysfunction cannot necessarily be ascribed to perioperative events.     

The murine homolog of the interleukin-8 receptor CXCR-2 is essential for the occurrence of neutrophilic inflammation in the air pouch model of acute urate crystal-induced gouty synovitis

OBJECTIVE: Acute neutrophil-dependent inflammation is central to acute gout. Urate crystals induce different classes of neutrophil chemotaxins, including certain chemokines (e.g., interleukin-8 [IL-8], growth-related oncogene alpha [GROalpha]) that share CXCR-2 as a receptor. This study was undertaken to assess the role of CXCR-2 ligands in a model of acute gout. METHODS: Urate crystals were injected into subcutaneous air pouches in mice that expressed or lacked the murine CXCR-2 homolog (mIL-8RH), and the development of neutrophilic inflammation was assessed. RESULTS: In normal mice, urate crystals induced a 10-fold increase (P < 0.01) in pouch fluid leukocytes (principally neutrophils) at 4 hours. Leukocytes adhered to the pouch lining, where crystals, the mIL-8RH ligand KC/GROalpha, and cells bearing mIL-8RH were abundant. In mIL-8RH(-/-) mice, urate crystals induced a proteinaceous leukocyte-poor exudate at 4 hours, despite crystal-induced activation of resident cells (documented by KC/GROalpha expression). CONCLUSION: Chemokines that bind the IL-8 receptor CXCR-2 are essential for the development of acute neutrophilic inflammation in response to urate crystals in the subcutaneous air pouch model.     

Crohn's disease of the prepuce in a 12-year-old boy: a case report and review of the literature

We report a case of Crohn's disease with involvement of the foreskin in a 12-year-old boy. One year previously, on the basis of clinical features (diarrhea with blood, perianal fissures) and histologic examination, a diagnosis of Crohn's disease was made. Subsequently, he developed phimosis and balanitis and underwent circumcision. Sections submitted from the foreskin revealed noncaseating granulomatous inflammation consistent with Crohn's disease. Crohn's disease with involvement of the genitalia is unusual. Only 26 cases including our case have been reported in the scientific literature. We have analyzed these cases with emphasis on gender, age, clinical features, duration of Crohn's disease, and probable mode of spread to the genitalia. Careful examination of sections from genital lesions, including those submitted from the foreskin, is essential to detect small isolated granulomas that may then lead to the diagnosis of inflammatory bowel disease.     

Heterozygosity for a defective gene for CC chemokine receptor 5 is not the sole determinant for the immunologic and virologic phenotype of HIV-infected long-term nonprogressors

HIV-1-infected long-term nonprogressors are a heterogeneous group of individuals with regard to immunologic and virologic markers of HIV-1 disease. CC chemokine receptor 5 (CCR5) has recently been identified as an important coreceptor for HIV-1 entry into CD4+ T cells. A mutant allele of CCR5 confers a high degree of resistance to HIV-1 infection in homozygous individuals and partial protection against HIV disease progression in heterozygotes. The frequency of CCR5 heterozygotes is increased among HIV-1- infected long-term nonprogressors compared with progressors; however, the host defense mechanisms responsible for nonprogression in CCR5 heterozygotes are unknown. We hypothesized that nonprogressors who were heterozygous for the mutant CCR5 gene might define a subgroup of nonprogressors with higher CD4+ T cell counts and lower viral load compared with CCR5 wild-type nonprogressors. However, in a cohort of 33 HIV-1-infected long-term nonprogressors, those who were heterozygous for the mutant CCR5 gene were indistinguishable from CCR5 wild-type nonprogressors with regard to all measured immunologic and virologic parameters. Although epidemiologic data support a role for the mutant CCR5 allele in the determination of the state of long-term nonprogression in some HIV-1- infected individuals, it is not the only determinant. Furthermore, long-term nonprogressors with the wild-type CCR5 genotype are indistinguishable from heterozygotes from an immunologic and virologic standpoint.     

Unilateral asymptomatic carotid disease does not require surgery

If a stimulus (e.g. tone or light) is repeatedly pre-exposed without consequences, it subsequently shows retarded conditioning when paired with a reinforcer (e.g. footshock) compared with a non-pre-exposed stimulus. This is latent inhibition (LI). Haloperidol-treated animals show potentiated LI, and it has been suggested that this is due to retarded switching to respond according to the stimulus-reinforcer contingency. Recently, it has been argued that the slowed control of behaviour by the stimulus-reinforcement contingency is due to a haloperidol-induced decrease in the impact, or salience, of the reinforcer, and thus should be antagonized by increasing the impact of reinforcement. Two experiments tested this prediction. In both, LI was assessed using an off-baseline conditioned emotional response procedure in rats licking for water. In Experiment 1, rats were given 10 light pre-exposures and conditioned with two footshocks of either a low (0.5 mA) or a high (1 mA) intensity. In Experiment 2, rats were given 30 pre-exposures and conditioned with either two or five footshocks of 1 mA. In Experiment 1, no-drug controls did not show LI at both shock intensities. Haloperidol (0.1 mg/kg) was ineffective in potentiating LI at low-intensity shock, but produced LI when shock level was increased. In Experiment 2, no-drug controls showed LI with two but not five conditioning trials. Haloperidol was ineffective in potentiating LI with two conditioning trials, but produced LI with five conditioning trials. Although the effect of haloperidol on LI could thus be modified by manipulating shock intensity or the number of conditioning trials, the direction of such modification indicates that the potentiating effect of haloperidol on LI is not in general antagonized by increasing the impact of reinforcement.     

Relation of olfactory EEG to behavior: Spatial analysis.

The hypothesis that odor-specific patterns of mitral cell activity during odor discrimination might be found in the corresponding spatial patterns of electroencephalogram (EEG) amplitude over a surgically accessible segment of the bulbar surface was tested in rabbits with chronically implanted electrode arrays. The spatial spectrum of the bulbar EEG was derived and compared with the spectrum predicted for the granule cell generator. Spatial filters were devised to identify, enhance, or remove the granule cell contribution to the EEG. Spatial deconvolution was applied to the filtered granule cell activity patterns to correct for distortion caused by the volume conduction. The results indicated that the bulb generated odor-specific spatial patterns in rabbits trained to discriminate between two odors. The odor-specific information was not localizable to subsets of channels. This suggested that the discriminative output of the bulb involved the entire structure, even though the receptor input was delivered to limited subsets of mitral cells. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distribution of fibroblast growth factor (FGF)-2 and FGF receptor-1 messenger RNA expression and protein presence in the mid-trimester human fetus

Fibroblast growth factors (FGF) are known to have key roles in embryonic growth and morphogenesis, but their presence and contributions to fetal development are unclear. In particular, little information exists as to the relevance of FGF and their specific receptors to human fetal development. We studied the anatomical distribution of messenger RNA encoding FGF-2 and one of its high affinity receptors, FGFR1, using in situ hybridization in a variety of human fetal tissues in early second trimester. Corresponding protein distributions were determined by immunohistochemistry. Both FGF-2 and FGFR1 mRNA and proteins were found to be present in every organ and tissue examined, but with defined cellular localizations. In skeletal muscle, both FGF-2 and FGFR1 mRNA and peptides were present in differentiated fibers, and both co-localized to proliferating chondrocytes of the epiphyseal growth plate. FGF-2 and FGFR1 mRNA and peptides were also present within cardiac or gastrointestinal smooth muscle. Within the gastrointestinal tract FGF-2 mRNA and peptide were located in the submucosal tissue, whereas FGFR1 was expressed within the overlying mucosa. Similarly, in skin, FGF-2 was expressed within the dermis whereas FGFR1 mRNA and peptide were most apparent in the stratum germinativum of the epidermis. In kidney and lung, FGFR1 mRNA was located in the tubular and alveolar epithelia respectively, whereas FGF-2 was expressed in both epithelial and mesenchymal cell populations. Both growth factor and receptor were widespread in both neuroblasts and glioblasts in the cerebral cortex of the brain. Immunoreactivity for FGF-2 and FGFR1 was seen in all vascular endothelial cells of major vessels and capillaries. Within the skin, kidney, lung, and intestine FGF-2 immunoreactivity was found in basement membranes underlying epithelia, and was associated with the extracellular matrix and plasma membranes of many cell types. The results show that FGF-2 and one of its receptors are widely expressed anatomically in the mid-trimester human fetus.