High‐Resolution 3D NIR‐II Photoacoustic Imaging of Cerebral and Tumor Vasculatures Using Conjugated Polymer Nanoparticles as Contrast Agent

Exogenous contrast‐agent‐assisted NIR‐II optical‐resolution photoacoustic microscopy imaging (ORPAMI) holds promise to decipher wide‐field 3D biological structures with deep penetration, large signal‐to‐background ratio (SBR), and high maximum imaging depth to depth resolution ratio. Herein, NIR‐II conjugated polymer nanoparticle (CP NP) assisted ORPAMI is reported for pinpointing cerebral and tumor vasculatures. The CP NPs exhibit a large extinction coefficient of 48.1 L g^?1 at the absorption maximum of 1161 nm, with an ultrahigh PA sensitivity up to 2 µg mL^?1. 3D ORPAMI of wide‐field mice ear allows clear visualization of regular vasculatures with a resolution of 19.2 µm and an SBR of 29.3 dB at the maximal imaging depth of 539 µm. The margin of ear tumor composed of torsional dense vessels among surrounding normal regular vessels can be clearly delineated via 3D angiography. In addition, 3D whole‐cortex cerebral vasculatures with large imaging area (48 mm²), good resolution (25.4 µm), and high SBR (22.3 dB) at a depth up to 1001 µm are clearly resolved through the intact skull. These results are superior to the recently reported 3D NIR‐II fluorescence confocal vascular imaging, which opens up new opportunities for NIR‐II CP‐NP‐assisted ORPAMI in various biomedical applications.     

CFD simulation study to investigate the risk from hydrogen vehicles in tunnels

When introducing hydrogen-fuelled vehicles, an evaluation of the potential change in risk level should be performed. It is widely accepted that outdoor accidental releases of hydrogen from single vehicles will disperse quickly, and not lead to any significant explosion hazard. The situation may be different for more confined situations such as parking garages, workshops, or tunnels. Experiments and computer modelling are both important for understanding the situation better. This article reports a simulation study to examine what, if any, is the explosion risk associated with hydrogen vehicles in tunnels. Its aim was to further our understanding of the phenomena surrounding hydrogen releases and combustion inside road tunnels, and furthermore to demonstrate how a risk assessment methodology developed for the offshore industry could be applied to the current task. This work is contributing to the EU Sixth Framework (Network of Excellence) project HySafe, aiding the overall understanding that is also being collected from previous studies, new experiments and other modelling activities.     

An inter-comparison exercise on CFD model capabilities to simulate hydrogen deflagrations in a tunnel

In the frame of the European Commission co-funded Network of Excellence HySafe (Hydrogen Safety as an Energy Carrier, www.hysafe.org), five organizations with significant experience in explosion modelling have performed numerical simulations of explosions of stoichiometric hydrogen–air mixtures in a 78.5 m long tunnel. The five organizations are the Karlsruhe Research Centre, GexCon AS, the Joint Research Centre, the Kurchatov Institute Research Centre and the University of Ulster. Five CFD (Computational Fluid Dynamics) codes with different turbulence and combustion models have been used in this Standard Benchmark Exercise Problem (SBEP). Since tunnels are semi-confined environments, hydrogen explosions in tunnels can potentially be critical accident scenarios from the point of view of the accident consequences and CFD methods are increasingly employed to assess explosions hazards in tunnels. The objective of the validation exercise is to assess the accuracy of the theoretical and numerical models by comparisons of the simulation results with the experimental data. A very good agreement between experiments and simulations was found in terms of maximum overpressures.     

Organic Small Molecule Based Photothermal Agents with Molecular Rotors for Malignant Breast Cancer Therapy

Organic photothermal nanoagents are promising candidates for treating primary tumors and inhibiting metastasis. However, they often exhibit poor photostability, low absorptivity, or limited photothermal conversion efficiency (PCE). Herein, a facile molecular engineering approach to produce efficient organic photothermal molecules is demonstrated. By integrating donor–acceptor structure and molecular motors, a small molecule ( TA1 ) is synthesized with large absorptivity (22.4 L g^?1 cm^?1), negligible reactive oxygen species generation, high PCE (84.8%), excellent photothermal stability, and good biocompatibility. Furthermore, microfluidics is used to thoroughly study the relationship between the size and process conditions, yielding small uniform nanoparticles (NPs) with a diameter of 44 nm. Importantly, TA1 NPs under near‐infrared laser irradiation significantly suppressed primary breast tumor growth and metastasis, both in vitro and in vivo. This study shows that small organic molecule nanoparticles are promising candidates for future cancer nanomedicine.     

A glimpse into the clinical proteome of human malaria parasites Plasmodium falciparum and Plasmodium vivax

Malaria causes a worldwide annual mortality of about a million people. Rapidly evolving drug-resistant species of the parasite have created a pressing need for the identification of new drug targets and vaccine candidates. By developing fractionation protocols to enrich parasites from low-parasitemia patient samples, we have carried out the first ever proteomics analysis of clinical isolates of early stages of Plasmodium falciparum (Pf) and P. vivax. Patient-derived malarial parasites were directly processed and analyzed using shotgun proteomics approach using high-sensitivity MS for protein identification. Our study revealed about 100 parasite-coded gene products that included many known drug targets such as Pf hypoxanthine guanine phosphoribosyl transferase, Pf L-lactate dehydrogenase, and Plasmepsins. In addition, our study reports the expression of several parasite proteins in clinical ring stages that have never been reported in the ring stages of the laboratory-cultivated parasite strain. This proof-of-principle study represents a noteworthy step forward in our understanding of pathways elaborated by the parasite within the malaria patient and will pave the way towards identification of new drug and vaccine targets that can aid malaria therapy.     

CFD computations of liquid hydrogen releases

Hydrogen is widely recognized as an attractive energy carrier due to its low-level air pollution and its high mass-related energy density. However, its wide flammability range and high burning velocity present a potentially significant hazard. A significant fraction of hydrogen is stored and transported as a cryogenic liquid (liquid hydrogen, or LH₂) as it requires much less volume compared to gaseous hydrogen. In order to exist as a liquid, H₂ must be cooled to a very low temperature, 20.28 K. LH₂ is a common liquid fuel for rocket applications. It can also be used as the fuel storage in an internal combustion engine or fuel cell for transport applications. Models for handling liquid releases, both two-phase flashing jets and pool spills, have been developed in the CFD-model FLACS. The very low normal boiling point of hydrogen (20 K) leads to particular challenges as this is significantly lower than the boiling points of oxygen (90 K) and nitrogen (77 K). Therefore, a release of LH₂ in the atmosphere may induce partial condensation or even freezing of the oxygen and nitrogen present in the air. A pool model within the CFD software FLACS is used to compute the spreading and vaporization of the liquid hydrogen depositing on the ground where the partial condensation or freezing of the oxygen and nitrogen is also taken into account. In our computations of two-phase jets the dispersed and continuous phases are assumed to be in thermodynamic and kinematic equilibrium. Simulations with the new models are compared against selected experiments performed at the Health and Safety Laboratory (HSL).     

Accidental hydrogen release in a gas chromatograph laboratory: A case study

A 50-litre standard hydrogen gas cylinder was temporarily placed in a laboratory to supply hydrogen gas to a flame ionization detector (FID) for use in gas chromatography (GC). On 20 January 2015, the safety relief valve on the pressure regulator failed and released about 0.34 kg of hydrogen into the laboratory. The gas cloud did not ignite so there was no injury or damage. The results of a full investigation with a complete course of action and reconstruction are presented that verify the cause of the leakage and estimate the gas concentration of the dispersion and gas cloud. A preliminary simulation of the likely explosion is provided. If the gas cloud had ignited, the explosion would most likely have caused significant structural damage to doors, windows, and possibly the walls.     

HySafe standard benchmark Problem SBEP-V11: Predictions of hydrogen release and dispersion from a CGH2 bus in an underpass

One of the tasks of the HySafe Network of Excellence was the evaluation of available CFD tools and models for dispersion and combustion in selected hydrogen release scenarios identified as “standard benchmark problems” (SBEPs). This paper presents the results of the HySafe standard benchmark problem SBEP-V11. The situation considered is a high pressure hydrogen jet release from a compressed gaseous hydrogen (CGH2) bus in an underpass. The bus considered is equipped with 8 cylinders of 5 kg hydrogen each at 35 MPa storage pressure. The underpass is assumed to be of the common beam and slab type construction with I-beams spanning across the highway at 3 m centres (normal to the bus), plus cross bracing between the main beams, and light armatures parallel to the bus direction. The main goal of the present work was to evaluate the role of obstructions on the underside of the bridge deck on the dispersion patterns and assess the potential for hydrogen accumulation. Four HySafe partners participated in this benchmark, with 4 different CFD codes, ADREA-HF, CFX, FLACS and FLUENT. Four scenarios were examined in total. In the base case scenario 20 kg of hydrogen was released in the basic geometry. In Sensitivity Test 1 the release position was moved so that the hydrogen jet could hit directly the light armature on the roof of the underpass. In Sensitivity Test 2 the underside of the bridge deck was flat. In Sensitivity Test 3 the release was from one cylinder instead of four (5 kg instead of 20). The paper compares the results predicted by the four different computational approaches and attempts to identify the reasons for observed disagreements. The paper also concludes on the effects of the obstructions on the underside of the bridge deck.     

在SoC设计中用SystemC虚拟平台预览USB的性能

现在的程序员和系统架构师有比以往更多的软件可用于SoC(单片系统)设计,但也面临着一个日益困扰他们的问题：如何在设计前期,在硅片拿到手以前评估和优化软件的性能。为解决这个问题,程序员们转向虚拟平台,这种平台采用软件来对目标硬件的架构和功能建模。