Multi-cue hand detection and tracking for a head-mounted augmented reality system

With the recent developments in wearable augmented reality (AR), the role of natural human–computer interaction is becoming more important. Utilization of auxiliary hardware for interaction introduces extra complexity, weight and cost to wearable AR systems and natural means of interaction such as gestures are therefore more desirable. In this paper, we present a novel multi-cue hand detection and tracking method for head-mounted AR systems which combines depth, color, intensity and curvilinearity. The combination of different cues increases the detection rate, eliminates the background regions and therefore increases the tracking performance under challenging conditions. Detected hand positions and the trajectories are used to perform actions such as click, select, etc. Moreover, the 6 DOF poses of the hands are calculated by approximating the segmented regions with planes in order to render a planar menu (interface) around the hand and use the hand as a planar selection tool. The proposed system is tested on different scenarios (including markers for reference) and the results show that our system can detect and track the hands successfully in challenging conditions such as cluttered and dynamic environments and illumination variance. The proposed hand tracker outperforms other well-known hand trackers under these conditions.     

Influence of thermal ageing on the stability of polymer bulk heterojunction solar cells

A new approach is presented in order to improve the thermal stability of polymer: [6-6]-phenyl C₆₁ butyric acid methyl ester (PCBM) bulk heterojunction solar cells. The central idea in this approach is the use of a polymer with high glass transition temperature (T_g), well above the normal operating temperatures of the devices. In this paper, a PPV-derivative with a T_g of 150 °C was used as an electron donor and the thermal stability of the obtained solar cells was compared with solar cells based on the reference material poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) with a T_g of 45 °C. The use of the material with higher glass transition temperature resulted in a significant improvement of the thermal stability of the photovoltaic parameters. Furthermore, a systematic transmission electron microscope (TEM) study demonstrates that the better thermal stability of performance coincides with a more stable active layer morphology. Both improvements are attributed to the reduced free movement of the electron donor material (PCBM) within the active layer of the solar cell.     

Correlation of Immunological and Histopathological Features with Gene Expression-Based Classifiers in Colon Cancer Patients

The purpose of this study was to evaluate the association between four distinct histopathological features: (1) tumor infiltrating lymphocytes, (2) mucinous differentiation, (3) tumor-stroma ratio, plus (4) tumor budding and two gene expression-based classifiers—(1) consensus molecular subtypes (CMS) plus (2) colorectal cancer intrinsic subtypes (CRIS). All four histopathological features were retrospectively scored on hematoxylin and eosin sections of the most invasive part of the primary tumor in 218 stage II and III colon cancer patients from two independent cohorts (AMC-AJCC-90 and AC-ICAM). RNA-based CMS and CRIS assignments were independently obtained for all patients. Contingency tables were constructed and a χ2 test was used to test for statistical significance. Odds ratios with 95% confidence intervals were calculated. The presence of tumor infiltrating lymphocytes and a mucinous phenotype (>50% mucinous surface area) were strongly correlated with CMS1 (p < 0.001 and p = 0.008) and CRIS-A (p = 0.006 and p < 0.001). The presence of mucus (≥ 10%) was associated with CMS3: mucus was present in 64.1% of all CMS3 tumors (p < 0.001). Although a clear association between tumor-stroma ratio and CMS4 was established in this study (p = 0.006), still 32 out of 61 (52.5%) CMS4 tumors were scored as stroma-low, indicating that CMS4 tumors cannot be identified solely based on stromal content. Higher budding counts were seen in CMS4 and CRIS-B tumors (p = 0.045 and p = 0.046). No other associations of the measured parameters were seen for any of the other CRIS subtypes. Our analysis revealed clear associations between histopathologic features and CMS or CRIS subtypes. However, identification of distinct molecular subtypes solely based on histopathology proved to be infeasible. Combining both molecular and morphologic features could potentially improve patient stratification.     

Activity-based profiling of retaining β-glucosidases: a comparative study

Activity-based protein profiling (ABPP) is a versatile strategy to report on enzyme activity in vitro, in situ, and in vivo. The development and use of ABPP tools and techniques has met with considerable success in monitoring physiological processes involving esterases and proteases. Activity-based profiling of glycosidases, on the other hand, has proven more difficult, and to date no broad-spectrum glycosidase activity-based probes (ABPs) have been reported. In a comparative study, we investigated both 2-deoxy-2-fluoroglycosides and cyclitol epoxides for their utility as a starting point towards retaining β-glucosidase ABP. We also investigated the merits of direct labeling and two-step bio-orthogonal labeling in reporting on glucosidase activity under various conditions. Our results demonstrate that 1) in general cyclitol epoxides are the superior glucosidase ABPs, 2) that direct labeling is the more efficient approach but it hinges on the ability of the glucosidase to be accommodated in the active site of the reporter (BODIPY) entity, and 3) that two-step bio-orthogonal labeling can be achieved on isolated enzymes but translating this protocol to cell extracts requires more investigation.     

Nonhydrolyzable Heptose Bis- and Monophosphate Analogues Modulate Pro-inflammatory TIFA-NF-κB Signaling

d -Glycero-d -manno-heptose-1β,7-bisphosphate (HBP) and d -glycero-d -manno-heptose-1β-phosphate (H1P) are bacterial metabolites that were recently shown to stimulate inflammatory responses in host cells through the activation of the TIFA-dependent NF-κB pathway. To better understand structure-based activity in relation to this process, a family of nonhydrolyzable phosphonate analogues of HBP and H1P was synthesized. The inflammation modulation by which these molecules induce the TIFA-NF-κB signal axis was evaluated in vivo at a low-nanomolar concentration (6 nM) and compared to that of the natural metabolites. Our data showed that three phosphonate analogues had similar stimulatory activity to HBP, whereas two phosphonates antagonized HBP-induced TIFA-NF-κB signaling. These results open new horizons for the design of pro-inflammatory and innate immune modulators that could be used as vaccine adjuvant.     

Secreted production of a custom-designed, highly hydrophilic gelatin in Pichia pastoris

A custom-designed, highly hydrophilic gelatin was produced inPichia pastoris. Secreted production levels in single-copytransformants were in the range 3–6 g/l of clarified brothand purification to near homogeneity could be accomplished bydifferential ammonium sulfate precipitation. Despite the factthat gelatins are highly susceptible to proteolysis becauseof their unfolded structure, the recombinant protein was shownto be fully intact by SDS–PAGE, N-terminal sequencing,gel filtration chromatography and mass spectrometry. Owing toits highly hydrophilic nature, the migration of the syntheticgelatin in SDS–PAGE was severely delayed. Esterificationof the carboxylic amino acid side chains resulted in normalmigration. The high polarity of the synthetic gelatin also accountsfor its negligible surface activity in water at concentrationsup to 5% (w/v), as determined by tensiometry. Circular dichroismspectrometry showed that the non-hydroxylated gelatin did notform triple helices at 4°C. The spectrum was even more representativeof the random coil conformation than the spectrum of naturalnon-hydroxylated gelatins.     

Extensional Flow and Relaxation of Semi‐dilute Solutions of Schizophyllan

Capillary thinning experiments of semi‐dilute solutions of schizophyllan in water and DMSO are performed to determine the relaxation behavior in extensional flows as experienced, for example, in the flow through porous media in enhanced oil recovery. The extensional relaxation time λ_E is found to scale with concentration following a dissimilar power‐law dependency for the two solvents, λ_E ∝ c^1.52 in water and λ_E ∝ c^0.90 in DMSO. It is shown that the extensional flow fields are strong enough to break, and prevent the rebuilding of, intermolecular structures, due to hydrogen bonding that was observed to alter the viscoelastic response in shearing flows of aqueous schizophyllan solutions.