Hands-Free Navigation in Immersive Environments for the Evaluation of the Effectiveness of Indoor Navigation Systems

While navigation systems for cars are in widespread use, only recently, indoor navigation systems based on smartphone apps became technically feasible. Hence tools in order to plan and evaluate particular designs of information provision are needed. Since tests in real infrastructures are costly and environmental conditions cannot be held constant, one must resort to virtual infrastructures. This paper presents the development of an environment for the support of the design of indoor navigation systems whose center piece consists in a hands-free navigation method using the Microsoft Kinect in the four-sided Definitely Affordable Virtual Environment (DAVE). Navigation controls using the user's gestures and postures as the input to the controls are designed and implemented. The installation of expensive and bulky hardware like treadmills is avoided while still giving the user a good impression of the distance she has traveled in virtual space. An advantage in comparison to approaches using a head mounted display is that the DAVE allows the users to interact with their smartphone. Thus the effects of different indoor navigation systems can be evaluated already in the planning phase using the resulting system

Visual acuity of dentists under simulated clinical conditions

OBJECTIVES This study examined the near visual acuity of dentists in relation to age and magnification under simulated clinical conditions. MATERIALS AND METHODS Miniaturized visual tests were performed in posterior teeth of a dental phantom head in a simulated clinical setting (dental chair, operating lamp, dental mirror). The visual acuity of 40 dentists was measured under the following conditions: (1) natural visual acuity, distance of 300 mm; (2) natural visual acuity, free choice of distance; (3) Galilean loupes, magnification of ×2.5; (4) Keplerian loupes, ×4.3; (5) operating microscope, ×4, integrated light; (6) operating microscope, ×6.4, integrated light. RESULTS The visual acuity varied widely between individuals and was significantly lower in the group ≥40 years of age (p < 0.001). Significant differences were found between all tested conditions (p < 0.01). Furthermore, a correlation between visual acuity and age was found for all conditions. The performance with the microscope was better than with loupes even with comparable magnification factors. Some dentists had a better visual acuity without optical aids than others with Galilean loupes. CONCLUSIONS Near visual acuity under simulated clinical conditions varies widely between individuals and decreases throughout life. Visual deficiencies can be compensated for with optical aids. CLINICAL RELEVANCE Newly developed miniaturized vision tests have allowed, in a clinically relevant way, to evaluate the influence of magnification and age on the near visual acuity of dentists.

Formation of haemozoin/β-haematin under physiological conditions is not spontaneous

Malaria parasite detoxifies free haem, released as a result of haemoglobin digestion, by converting it into an stable, crystalline, black brown pigment known as 'malaria pigment' or 'haemozoin'. Earlier studies have demonstrated the involvement of a parasite-specific enzyme 'haem polymerase' in the formation of haemozoin. However, recently it has been proposed that the polymerization of haem may be a spontaneous process that could take place by incubation of haematin with carboxylic acids (pH 4.2-5.0) even without presence of any parasitic or biological component (FEBS Letters, 352, 54-57 (1994). Here we report that no spontaneous haem polymerization occurs at physiological conditions and the product described in the study mentioned above is not haemozoin/beta-haematin (haem polymer) as characterized by us on the basis of solubility characteristics and thin layer chromatography. The infra-red spectroscopic analysis of the product formed though exhibits the bands corresponding to formation of iron-carboxylate bond, similar to that in haemozoin/beta-haematin, but was identified as haem-acid adduct. Thus polymerization of haem may not occur spontaneously under the reaction conditions corresponding to food vacuoles of the malarial parasite, the physiological site of haemozoin formation.

Long-lasting synaptic potentiation induced by depolarization under conditions that eliminate detectable Ca2+ signals.

Activity-dependent alterations of synaptic transmission important for learning and memory are often induced by Ca(2+) signals generated by depolarization. While it is widely assumed that Ca(2+) is the essential transducer of depolarization into cellular plasticity, little effort has been made to test whether Ca(2+)-independent responses to depolarization might also induce memory-like alterations. It was recently discovered that peripheral axons of nociceptive sensory neurons in Aplysia display long-lasting hyperexcitability triggered by conditioning depolarization in the absence of Ca(2+) entry (using nominally Ca(2+)-free solutions containing EGTA, "0Ca/EGTA") or the absence of detectable Ca(2+) transients (adding BAPTA-AM, "0Ca/EGTA/BAPTA-AM"). The current study reports that depolarization of central ganglia to approximately 0 mV for 2 min in these same solutions induced hyperexcitability lasting >1 h in sensory neuron processes near their synapses onto motor neurons. Furthermore, conditioning depolarization in these solutions produced a 2.5-fold increase in excitatory postsynaptic potential (EPSP) amplitude 1-3 h afterward despite a drop in motor neuron input resistance. Depolarization in 0 Ca/EGTA produced long-term potentiation (LTP) of the EPSP lasting > or = 1 days without changing postsynaptic input resistance. When re-exposed to extracellular Ca(2+) during synaptic tests, prior exposure to 0Ca/EGTA or to 0Ca/EGTA/BAPTA-AM decreased sensory neuron survival. However, differential effects on neuronal health are unlikely to explain the observed potentiation because conditioning depolarization in these solutions did not alter survival rates. These findings suggest that unrecognized Ca(2+)-independent signals can transduce depolarization into long-lasting synaptic potentiation, perhaps contributing to persistent synaptic alterations following large, sustained depolarizations that occur during learning, neural injury, or seizures.

Development of a high- versus low-pathogenicity model of the free-living amoeba Naegleria fowleri

Species in the genus Naegleria are free-living amoebae of the soil and warm fresh water. Although around 30 species have been recognized, Naegleria fowleri is the only one that causes primary amoebic meningoencephalitis (PAM) in humans. PAM is an acute and fast progressing disease affecting the central nervous system. Most of the patients die within 1-2 weeks of exposure to the infectious water source. The fact that N. fowleri causes such fast progressing and highly lethal infections has opened many questions regarding the relevant pathogenicity factors of the amoeba. In order to investigate the pathogenesis of N. fowleri under defined experimental conditions, we developed a novel high- versus low-pathogenicity model for this pathogen. We showed that the composition of the axenic growth media influenced growth behaviour and morphology, as well as in vitro cytotoxicity and in vivo pathogenicity of N. fowleri. Trophozoites maintained in Nelson's medium were highly pathogenic for mice, demonstrated rapid in vitro proliferation, characteristic expression of surface membrane vesicles and a small cell diameter, and killed target mouse fibroblasts by both contact-dependent and -independent destruction. In contrast, N. fowleri cultured in PYNFH medium exhibited a low pathogenicity, slower growth, increased cell size and contact-dependent target cell destruction. However, cultivation of the amoeba in PYNFH medium supplemented with liver hydrolysate (LH) resulted in trophozoites that were highly pathogenic in mice, and demonstrated an intermediate proliferation rate in vitro, diminished cell diameter and contact-dependent target cell destruction. Thus, in this model, the presence of LH resulted in increased proliferation of trophozoites in vitro and enhanced pathogenicity of N. fowleri in mice. However, neither in vitro cytotoxicity mechanisms nor the presence of membrane vesicles on the surface correlated with the pathologic potential of the amoeba. This indicated that the pathogenicity of N. fowleri remains a complex interaction between as-yet-unidentified cellular mechanisms.

Visual acuity of dentists in their respective clinical conditions.

OBJECTIVES This study examined the impact of age and magnification on the near visual acuity of dentists in their private practice under simulated clinical conditions. MATERIALS AND METHODS Miniaturized visual tests were fixed in posterior teeth of a dental phantom head and brought to 31 dentists in their respective private practice. The visual acuity of these dentists (n = 19, ≥40 years; n = 12, <40 years) was measured in a clinical setting under the following conditions: (a) natural visual acuity, distance of 300 mm; (b) natural visual acuity, free choice of the distance; and (c) loupe and additional light source, if available. RESULTS The visual acuity under the different clinical conditions varied widely between individuals. The older group of dentists had a lower median visual acuity value under all clinical conditions. This difference was highly significant for natural visual acuity at a free choice of distance (p < 0.0001). For younger dentists (<40 years), visual acuity could be significantly improved by reducing the eye-object distance (p = 0.001) or by using loupes (p = 0.008). For older dentists (≥40 years), visual acuity could be significantly improved by using loupes (p = 0.0005). CONCLUSIONS Visual performance decreased with increasing age under the specific clinical conditions of each dentist's private practice. Magnification aids can compensate for visual deficiencies. CLINICAL RELEVANCE The question of whether findings obtained under standardized conditions are valuable for the habitual setting of each dentist's private practice seems clinically relevant.

Combined Secondary Ion Mass Spectrometry Depth Profiling and Focused Ion Beam Analysis of Cu Films Electrodeposited under Oscillatory Conditions

The recrystallization behavior of Cu films electrodeposited under oscillatory conditions in the presence of plating additives was studied by means of secondary ion mass spectrometry (SIMS) and focused ion beam analysis. When combined with bis-(sodium-sulfopropyl)-disulfide (SPS), Imep levelers (polymerizates of imidazole and epichlorohydrin) show characteristic oscillations in the galvanostatic potential/time transient measurements. These are related to the periodic degradation and restoration of the active leveler ensemble at the interface. The leveler action relies on adduct formation between the Imep and MPS (mercaptopropane sulfonic acid)-stabilized CuI complexes that appear as intermediates of the copper deposition when SPS is present in the electrolyte. SIMS depth profiling proves that additives are incorporated into the growing film preferentially under transient conditions during the structural breakdown of the leveler ensemble and its subsequent restoration. In contrast, Cu films electrodeposited in the presence of a structurally intact Imep–CuI–MPS ensemble remain largely contamination free.

The role of the right frontal eye field in overt visual attention deployment as assessed by free visual exploration

The frontal eye field (FEF) is known to be involved in saccade generation and visual attention control. Studies applying covert attentional orienting paradigms have shown that the right FEF is involved in attentional shifts to both the left and the right hemifield. In the current study, we aimed at examining the effects of inhibitory continuous theta burst (cTBS) transcranial magnetic stimulation over the right FEF on overt attentional orienting, as measured by a free visual exploration paradigm. In forty-two healthy subjects, free visual exploration of naturalistic pictures was tested in three conditions: (1) after cTBS over the right FEF; (2) after cTBS over a control site (vertex); and, (3) without any stimulation. The results showed that cTBS over the right FEF-but not cTBS over the vertex-triggered significant changes in the spatial distribution of the cumulative fixation duration. Compared to the group without stimulation and the group with cTBS over the vertex, cTBS over the right FEF decreased cumulative fixation duration in the left and in the right peripheral regions, and increased cumulative fixation duration in the central region. The present study supports the view that the right FEF is involved in the bilateral control of not only covert, but also of overt, peripheral visual attention.

PLACENTAL URIC ACID TRANSPORTER GLUT9 IS MODULATED BY FREE IODINE

PLACENTAL URIC ACID TRANSPORTER GLUT9 IS MODULATED BY FREE IODINE Objectives: Materno-fetal transplacental transport is crucial for the fetal well-being. The altered expression of placental transport proteins under specific pathophysiological conditions may affect the intrauterine environment. Pre-eclampsia is often associated with high maternal uric acid serum levels. The regulation of the placental uric transport system and its transporter glucose transporter (GLUT)-9 are not fully understood yet. The aim of this study was to investigate the placental urate transport and to characterize its transporter GLUT9. Methods: In this study we used a transepithelial transport (Transwell®) model to assess uric acid transport activity. Electrophysiological techniques and radioactive ligand up-take assays were used to measure transport activity of GLUT9 expressed in Xenopus oocytes. Results: In the Transwell/model uric acid is transported across the BeWo choriocarcinoma cell monolayer with 530 pmol/min at the linear stage. We could successfully over-express GLUT9 using the Xenopus laevis oocytes expression system. Chloride modulates the urate transport system: interestingly replacing chloride with iodine resulted in a complete loss of urate transport activity.We determined the IC50 of iodine at 30uM concentration. In radioactive up-take experiments iodinehad noeffect on uric acid transport. Conclusions: In vitro the “materno-fetal” transport of uric acid is slow. This indicates that in vivo the child is protected from short-term fluctuations of maternal uric acid serum concentrations. The different results regarding iodine-mediated regulation of GLUT9 transport activity between electrophysiological and radioactive ligand uptake experiments may suggest that iodine does not directly inhibit uric acid transport, but changes the mode of up-take from an electrogenic to an electroneutral transport. GLUT9 is not an uric acid uniporter, there are more ions involved in the transport. This may allow regulating uric acid transport by the change from an active to a passive transport.

Echinococcus multilocularis Detection in Live Eurasian Beavers (Castor fiber) Using a Combination of Laparoscopy and Abdominal Ultrasound under Field Conditions.

Echinococcus multilocularis is an important pathogenic zoonotic parasite of health concern, though absent in the United Kingdom. Eurasian beavers (Castor fiber) may act as a rare intermediate host, and so unscreened wild caught individuals may pose a potential risk of introducing this parasite to disease-free countries through translocation programs. There is currently no single definitive ante-mortem diagnostic test in intermediate hosts. An effective non-lethal diagnostic, feasible under field condition would be helpful to minimise parasite establishment risk, where indiscriminate culling is to be avoided. This study screened live beavers (captive, n = 18 or wild-trapped in Scotland, n = 12) and beaver cadavers (wild Scotland, n = 4 or Bavaria, n = 11), for the presence of E. multilocularis. Ultrasonography in combination with minimally invasive surgical examination of the abdomen by laparoscopy was viable under field conditions for real-time evaluation in beavers. Laparoscopy alone does not allow the operator to visualize the parenchyma of organs such as the liver, or inside the lumen of the gastrointestinal tract, hence the advantage of its combination with abdominal ultrasonography. All live beavers and Scottish cadavers were largely unremarkable in their haematology and serum biochemistry with no values suspicious for liver pathology or potentially indicative of E. multilocularis infection. This correlated well with ultrasound, laparoscopy, and immunoblotting, which were unremarkable in these individuals. Two wild Bavarian individuals were suspected E. multilocularis positive at post-mortem, through the presence of hepatic cysts. Sensitivity and specificity of a combination of laparoscopy and abdominal ultrasonography in the detection of parasitic liver cyst lesions was 100% in the subset of cadavers (95%Confidence Intervals 34.24-100%, and 86.7-100% respectively). For abdominal ultrasonography alone sensitivity was only 50% (95%CI 9.5-90.6%), with specificity being 100% (95%CI 79.2-100%). For laparoscopy alone sensitivity was 100% (95% CI 34.2-100%), with specificity also being 100% (95% CI 77.2-100%). Further immunoblotting, PCR and histopathological examination revealed one individual positive for E. multilocularis, whilst the other individual was positive for Taenia martis.

Experimental dissolution of molybdenum-sulphides at low oxygen concentrations: A first-order approximation of late Archean atmospheric conditions

The abundance of atmospheric oxygen and its evolution through Earth's history is a highly debated topic. The earliest change of the Mo concentration and isotope composition of marine sediments are interpreted to be linked to the onset of the accumulation of free O2 in Earth's atmosphere. The O2 concentration needed to dissolve significant amounts of Mo in water is not yet quantified, however. We present laboratory experiments on pulverized and surface-cleaned molybdenite (MoS2) and a hydrothermal breccia enriched in Mo-bearing sulphides using a glove box setup. Duration of an experiment was 14 days, and first signs of oxidation and subsequent dissolution of Mo compounds start to occur above an atmospheric oxygen concentration of 72 ± 20 ppmv (i.e., 2.6 to 4.6 × 10−4 present atmospheric level (PAL)). This experimentally determined value coincides with published model calculations supporting atmospheric O2 concentrations between 1 × 10−5 to 3 × 10−4 PAL prior to the Great Oxidation Event and sets an upper limit to the molecular oxygen needed to trigger Mo accumulation and Mo isotope variations recorded in sediments. In combination with the published Mo isotope composition of the rock record, this result implies an atmospheric oxygen concentration prior to 2.76 Ga of below 72 ± 20 ppmv.

Antarctic Zone nutrient conditions during the last two glacial cycles

In a sediment core from the Pacific sector of the Antarctic Zone (AZ) of the Southern Ocean, we report diatom-bound N isotope (δ15Ndb) records for total recoverable diatoms and two distinct diatom assemblages (pennate and centric rich). These data indicate tight coupling between the degree of nitrate consumption and Antarctic climate across the last two glacial cycles, with δ15Ndb (and thus the degree of nitrate consumption) increasing at each major Antarctic cooling event. Coupled with evidence from opal- and barium-based proxies for reduced export production during ice ages, the δ15Ndb increases point to ice age reductions in the supply of deep ocean-sourced nitrate to the AZ surface. The two diatom assemblages and species abundance data indicate that the δ15Ndb changes are not the result of changing species composition. The pennate and centric assemblage δ15Ndb records indicate similar changes but with a significant decline in their difference during peak ice ages. A tentative seasonality-based interpretation of the centric-to-pennate δ15Ndb difference suggests that late summer surface waters became nitrate free during the peak glacials.

Proliferative kidney disease in brown trout – infection level, pathology and mortality under field conditions

Proliferative kidney disease (PKD) is an emerging disease threatening wild salmonid populations. In temperature-controlled aquaria, PKD can cause mortality rates of up to 85% in rainbow trout. So far, no data about PKD-related mortality in wild brown trout Salmo trutta fario are available. The aim of this study was to investigate mortality rates and pathology in brown trout kept in a cage within a natural river habitat known to harbor Tetracapsuloides bryosalmonae. Young-of-the-year (YOY) brown trout, free of T. bryosalmonae, were exposed in the River Wutach, in the northeast of Switzerland, during 3 summer months. Samples of wild brown trout caught by electrofishing near the cage location were examined in parallel. The incidence of PKD in cage-exposed animals (69%) was not significantly different to the disease prevalence of wild fish (82 and 80% in the upstream and downstream locations, respectively). The mortality in cageexposed animals, however, was as low as 15%. At the termination of the exposure experiment, surviving fish showed histological lesions typical for PKD regression, suggesting that many YOY brown trout survive the initial infection. Our results at the River Wutach suggest that PKD in brown trout does not always result in high mortality under natural conditions.

SAMPLING METHODOLOGY FOR AIRBORNE SEMIVOLATILE ORGANIC POLLUTANTS USING POLYURETHANE FOAMS (COLLECTION, PESTICIDES, VOLATILE)

Indoor and ambient air organic pollutants have been gaining attention because they have been measured at levels with possible health effects. Studies have shown that most airborne polychlorinated biphenyls (PCBs), pesticides and many polycyclic aromatic hydrocarbons (PAHs) are present in the free vapor state. The purpose of this research was to extend recent investigative work with polyurethane foam (PUF) as a collection medium for semivolatile compounds. Open-porous flexible PUFs with different chemical makeup and physical properties were evaluated as to their collection affinities/efficiencies for various classes of compounds and the degree of sample recovery. Filtered air samples were pulled through plugs of PUF spiked with various semivolatiles under different simulated environmental conditions (temperature and humidity), and sampling parameters (flow rate and sample volume) in order to measure their effects on sample breakthrough volume (V(,B)). PUF was also evaluated in the passive mode using organo-phosphorus pesticides. Another major goal was to improve the overall analytical methodology; PUF is inexpensive, easy to handle in the field and has excellent airflow characteristics (low pressure drop). It was confirmed that the PUF collection apparatus behaves as if it were a gas-solid chromatographic system, in that, (V(,B)) was related to temperature and sample volume. Breakthrough volumes were essentially the same using both polyether and polyester type PUF. Also, little change was observed in the V(,B)s after coating PUF with common chromatographic liquid phases. Open cell (reticulated) foams gave better recoveries than closed cell foams. There was a slight increase in (V(,B)) with an increase in the number of cells/pores per inch. The high-density polyester PUF was found to be an excellent passive and active collection adsorbent. Good recoveries could be obtained using just solvent elution. A gas chromatograph equipped with a photoionization detector gave excellent sensitivities and selectivities for the various classes of compounds investigated. ^

Early stage breast cancer and comorbidities: Their impact on breast cancer disease-free survival differences by ethnicity

The retrospective cohort study examined the association between the presence of comorbidities and breast cancer disease-free survival rates among racial/ethnic groups. The study population consisted of 2389 women with stage I and II invasive breast cancer who were diagnosed and treated at the M.D. Anderson Cancer Center between 1985 and 2000. It has been suggested that as the number of comorbidities increases, breast cancer mortality increases. It is known that African Americans and Hispanics are considered to be at a higher risk for comorbid conditions such as hypertension and diabetes compared to Caucasian women (23) (10). When compared to Caucasian women, African American women also have a higher breast cancer mortality rate (1). As a result, the study also examined whether comorbid conditions contribute to racial differences in breast cancer disease-free survival. Among the study population, 24% suffered from breast cancer recurrence, 6% died from breast cancer and 24% died from all causes. The mean age was 56 with 41% of the population being women between the ages of 40-55. One or more comorbidities were reported in 84 (36%) African Americans (OR 1.57; 95% CI 1.19-2.10), 58 (31%) Hispanics (OR 1.25; 95% CI 0.90-1.74) compared to the reference group of 531 (27%) Caucasians. Additionally, African American women were significantly more likely to suffer from either a breast cancer recurrence or breast cancer death (OR 1.5; 95% CI 0.70-1.41) when compared to Caucasian women. Multivariate analysis found hypertension (HR 1.22; 95% CI 0.99-1.49; p<0.05) to be statistically significant and a potential prognostic tool for disease-free survival with African American women (OR 2.96; 95% 2.25-3.90) more likely to suffer from hypertension when compared to Caucasian women. When compared to Caucasian women, Hispanics were also more likely to suffer from hypertension (OR 1.33; 95% CI 0.96-1.83). This suggests that comorbid conditions like hypertension could account for the racial disparities that exist when comparing breast cancer survival rates. Future studies should investigate this relationship further.^