High-throughput fabrication of anti-counterfeiting colloid-based photoluminescent microtags using electrical nanoimprint lithography

This work demonstrates the excellent capability of the recently developed electrical nanoimprint lithography (e-NIL) technique for quick, high-throughput production of well-defined colloid assemblies on surfaces. This is shown by fabricating micron-sized photoluminescent quick response (QR) codes based on the electrostatic directed trapping (so called nanoxerography process) of 28 nm colloidal lanthanide-doped upconverting NaYF4 nanocrystals. Influencing experimental parameters have been optimized and the contribution of triboelectrification in e-NIL was evidenced. Under the chosen conditions, more than 300 000 nanocrystal-based QR codes were fabricated on a 4 inch silicon wafer, in less than 15 min. These microtags were then transferred to transparent flexible films, to be easily integrated onto desired products. Invisible to the naked eye, they can be decoded and authenticated using an optical microscopy image of their specific photoluminescence mapping. Beyond this very promising application for product tracking and the anti-counterfeiting strategies, e-NIL nanoxerography, potentially applicable to any types of charged and/or polarizable colloids and pattern geometries opens up tremendous opportunities for industrial scale production of various other kinds of colloid-based devices and sensors.

Influence of longitudinal mode beating on laser-induced damage in fused silica

In our study, the laser-induced damage densities on a fused silica surface produced by multiple longitudinal mode (MLM) pulses are found to be higher than those produced by single longitudinal mode pulses at 1064 nm. This behavior is explained by the enhancement of the three-photon absorption due to the intensity spikes related to longitudinal mode beating. At 355 nm, the absorption is linear and an opposite behavior occurs. It can be explained with the help of a process involving thermomechanics coupled with the fine time structure of MLM pulses, leading to the possible annealing of part of the absorbent defects.

Cellular communication via nanoparticle-transporting biovesicles

AIMS

Endothelial cells are dynamic cells tasked with selective transport of cargo from blood vessels to tissues. Here we demonstrate the potential for nanoparticle transport across endothelial cells in membrane-bound vesicles.

MATERIALS & METHODS

Cell-free endothelial-derived biovesicles were characterized for cellular and nanoparticle content by electron microscopy. Confocal microscopy was used to evaluate biovesicles for organelle-specific proteins, and to monitor biovesicle engulfment by naive cells.

RESULTS

Nanoparticle-laden biovesicles containing low-density polyethyleneimine nanoparticles appear to be predominately of endosomal origin, combining features of multivesicular bodies, lysosomes and autophagosomes. Conversely, high-density polyethyleneimine nanoparticles stimulate the formation of biovesicles associated with cellular apoptotic breakdown. Secreted LAMP-1-positive biovesicles are internalized by recipient cells, either of the same origin or of novel phenotype.

CONCLUSION

Cellular biovesicles, rich in cellular signals, present an important mode of cell-to-cell communication either locally or through broadcasting of biological messages.

Mechanisms of Defect Generation and Clustering in CH3S Self-Assembled Monolayers on Au(111)

Periodic density functional calculations probe that step edges play a key role as source of defects during self-assembly. It is shown that the self-assembly process strongly reduces the energy required to strip an atom from the gold surface, locally increasing the concentration of surface defects. The thermodynamic driving force for the atom stripping is considerably more favorable along step-edge lines within the self-assembly than on the higher-coordinated terrace sites. Furthermore, the clustering of surface defects is considered, and we probe that the formation of aggregates of vacancies in the form of vacancy pits significantly stabilizes the self-assembly on the terraces of gold, where the role of the step edges is expected to be less significant. The high stability of pit-like structures arises from a balance between the corrugation and the enhanced bonding of defect-rich substrates. Our results demonstrate the important role that step edges play during assembly and could be very valuable for discovering defect-free assembled structures.

Analysis of exosome release and its prognostic value in human colorectal cancer

A significant proportion of extracellular nucleic acids in plasma circulate highly protected in tumor-specific exosomes, but it is unclear how the release of exosomes is modulated in carcinogenesis. We quantified by cytometry exosomes in plasma of 91 colorectal cancer patients to evaluate their potential as a tumor indicator and their repercussions on diagnosis and prognosis. We examined the involvement of TSAP6, a TP53-regulated gene involved in the regulation of vesicular secretion, in levels of circulating exosomes in plasma of colorectal patients and in HCT116 TP53-(wild-type and null) human colorectal cancer cell lines. The fraction of exosomes in cancer patients was statistically higher than in healthy controls (mean rank ¼ 53.93 vs. 24.35). High levels of exosomes in plasma of patients correlated with high levels of carcino-embryonic antigen (P ¼ 0.029) and with poorly differentiated tumors (P ¼ 0.039) and tended to have shorter overall survival than patients with low levels (P ¼ 0.056). Release of exosomes did not correlate with TSAP6 expression; and regulation of TSAP6 by TP53 was not shown either in tumor samples or in HCT116 cell lines. Although it was not suggested that the TP53/TSAP6 pathway regulates the release of exosomes into the plasma of colorectal cancer patients, the level of circulating exosomes may be used as a tumor indicator, because it correlates with poor prognosis parameters and shorter survival.

Extraction of the characteristics of Si nanocrystals by the charge pumping technique

In this paper, the characteristics of silicon nanocrystals used as charge trapping centers in memory devices are examined using the two-level charge pumping (CP) technique performed as a function of frequency and energy filtered transmission electron microscopy (EFTEM). The parameters extracted from the two methods such as the depth location, density and effective diameter of the nanocrystals are in good quantitative agreement. These results validate the charge pumping approach as a non-destructive powerful technique to access most of the properties of nanocrystals embedded in dielectrics and located at injection distances from the substrate surface not limited to the direct tunneling regime.

Factors affecting pupation success of the small hive beetle, Aethina tumida

Survivorship of larvae of the small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), was measured after they were raised on one of six diets. The effects of container shape (wide and shallow vs. narrow and deep), soil depth (0, 0.5, 1.0, 2.0, 4.0, and 8.0 cm), and temperature (28°, 32°, or 35° C) on pupation success was measured. Diet influenced larval survivorship, but did not have a strong effect on larval weight. The larvae fed only bee brood survived the shortest period of time. The larvae that were denied pupation substrate, fed only honey and pollen, and no other food or water after 20 days, had a median survivorship of 47.6 days, with a maximum of 61 days, while those fed only brood had a median survivorship of 18.2 days. Pupation substrate was essential for successful pupation, and the depth of the substrate, not its top surface area, was the crucial factor. Pupation success in narrow and deep containers was 95.6% on average, but only 12.5% in wide and shallow containers, using the same soil volume. In narrow and deep containers, most or all larvae kept in 4-8 cm of soil pupated at all temperatures, few larvae kept at 2 cm soil depth pupated, one out of 240 kept at 1.0 cm pupated, and no larvae kept at soil depths of 0 or 0.5 cm pupated.

Design, history and results of the Thiazolidinedione Intervention with vitamin D Evaluation (TIDE) randomised controlled trial

AIMS/OBJECTIVE

Conflicting data regarding cardiovascular effects of thiazolidinediones (TZDs) and extra-skeletal effects of vitamin D supported the need for a definitive trial. The Thiazolidinedione Intervention with vitamin D Evaluation (TIDE) trial aimed to assess the effects of TZDs (rosiglitazone and pioglitazone) on cardiovascular outcomes and the effects of vitamin D (cholecalciferol) on cancers and mortality.

METHODS

A large multicentre 3 × 2 factorial double-blind placebo-controlled randomised trial recruited from outpatient primary care and specialty clinics in 33 countries. From June 2009 to July 2010, 1,332 people with type 2 diabetes and other cardiovascular risk factors aged ≥ 50 years whose HbA(1c) was 6.5-9.5% (48-80 mmol/mol) when using two or fewer glucose-lowering drugs were randomised by a central computer system to placebo (n = 541), rosiglitazone 4-8 mg/day (n = 399) or pioglitazone 30-45 mg/day (n = 392); 1,221 participants were randomised to placebo (n = 614) or vitamin D 1,000 IU/day (n = 607). Participants and all study personnel were blind to treatment allocation. The primary outcome for the TZD arm was the composite of myocardial infarction, stroke or cardiovascular death, and for the vitamin D arm it was cancer or all-cause death. All randomised participants were included in the primary analysis.

RESULTS

From the study design, 16,000 people were to be followed for approximately 5.5 years. However, the trial was stopped prematurely because of regulatory concerns after a mean of 162 days without consideration of the accrued data. In the TZD arm, the cardiovascular outcome occurred in five participants (0.9%) in the placebo groups and three participants (0.4%) in the TZD groups (two allocated to pioglitazone, one to rosiglitazone). In the vitamin D arm, the primary outcome occurred in three participants (0.5%) in the placebo group and in two participants (0.3%) receiving vitamin D. Adverse events were comparable in all groups.

CONCLUSIONS/INTERPRETATION

Uncertainty persists regarding the clinically relevant risks and benefits of TZDs and vitamin D because of the early cancellation of this comprehensive trial.

Differential performance of tropical soda apple and its biological control agent Gratiana boliviana (Coleoptera: Chrysomelidae) in open and shaded habitats

The leaf feeding beetle Gratiana boliviana Spaeth has been released since 2003 in the southeastern United States for biological control of tropical soda apple, Solanum viarum Dunal. In Florida, G. boliviana can be found on tropical soda apple growing in open pastures as well as in shady wooded areas. The objectives of this study were to determine the effect of light intensity on the performance of tropical soda apple and G. boliviana under greenhouse conditions, and to determine the abundance and mortality of G. boliviana in open and shaded habitats. Leaves growing in the shade were less tough, had higher water and nitrogen content, lower soluble sugars, and less dense and smaller glandular trichomes compared with leaves growing in the open. Plants grew slightly taller and wider under shaded conditions but total biomass was significantly reduced compared with plants grown in the open. In the greenhouse, G. boliviana had higher immature survival, greater folivory, larger adult size, and higher fecundity when reared on shaded plants compared with open plants. Sampling of field populations revealed that the overall abundance of G. boliviana was lower but leaf feeding damage was higher in shaded habitats compared with the open habitats. The percentage of eggs surviving to adult was greater in shaded compared with open habitats. The abundance of predators was higher in the open pasture and was positively correlated with the abundance of G. boliviana. These results indicate that not only plant quality but also habitat structure are important to the performance of weed biological control agents.