A wide-range experimental and theoretical investigation of ammonia gas-phase oxidation is performed, and a predictive, detailed kinetic model is developed.

a b s t r a c tAmmonia oxidation experiments were conducted at high pressure (30 bar and 100 bar) under oxidizing and stoichiometric conditions, respectively, and temperatures ranging from 450 to 925 K. The oxidation of ammonia was slow under stoichiometric conditions in the temperature range investigated. Under oxidizing conditions the onset temperature for reaction was 850-875 K at 30 bar, while at 100 bar it was about 800 K, with complete consumption of NH 3 at 875 K. The products of reaction were N 2 and N 2 O, while NO and NO 2 concentrations were below the detection limit even under oxidizing conditions. The data were interpreted in terms of a detailed chemical kinetic model.

PurposeIn an effort for early assessment of treatment response, we investigate radiation induced changes in quantitative CT features of tumor during the delivery of chemoradiation therapy (CRT) for pancreatic cancer. MethodsDiagnostic-quality CT data acquired daily during routine CT-guided CRT using a CT-onrails for 20 pancreatic head cancer patients were analyzed. On each daily CT, the pancreatic head, the spinal cord and the aorta were delineated and the histograms of CT number (CTN) in these contours were extracted. Eight histogram-based radiomic metrics including the mean CTN (MCTN), peak position, volume, standard deviation (SD), skewness, kurtosis, energy and entropy were calculated for each fraction. Paired t-test was used to check the significance of the change of specific metric at specific time. GEE model was used to test the association between changes of metrics over time for different pathology responses. ResultsIn general, CTN histogram in the pancreatic head (but not in spinal cord) changed during the CRT delivery. Changes from the 1 st to the 26 th fraction in MCTN ranged from -15.8 to 3.9HU with an average of -4.7 HU (p<0.001). Meanwhile the volume decreased, the skewness increased (less skewed), and the kurtosis decreased (less peaked). Data Availability Statement: All relevant data are within the paper. Funding:The authors received no specific funding for this work. Competing interests:The authors have declared that no competing interests exist.pathological response is associated with the changes of MCTN, SD, and skewness. In cases of good response, patients tend to have large reductions in MCTN and skewness, and large increases in SD and kurtosis. ConclusionsSignificant changes in CT radiomic features, such as the MCTN, skewness, and kurtosis in tumor were observed during the course of CRT for pancreas cancer based on quantitative analysis of daily CTs. These changes may be potentially used for early assessment of treatment response and stratification for therapeutic intensification.

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The successful treatment of osteomyelitis remains a great challenge in the field of orthopedics. The clinical method for treating refractory bone infection requires a combination therapy of long-term systemic antibiotics administration and surgical debridement. It is highly desirable to develop an antibiotic-free, noninvasive, rapid strategy to eradicate osteomyelitis. Herein, we fabricate a piezoelectricenhanced sonosensitizer that consists of a porphyrin-based hollow metal−organic framework (HNTM), MoS 2 nanosheets, and a red cell (RBC) membrane. We find that the ultrasound (US)-induced piezoelectric polarization of MoS 2 can improve the charge transfer of HNTM at the heterointerface of HNTM-MoS 2 , increasing the production of reactive oxygen species (ROS). Besides, MoS 2 increases the asymmetric shape of HNTM, leading to the strong US-propelling ability of HNTM−MoS 2 . The produced ROS and strong mechanical force can kill methicillin-resistant Staphylococcus aureus (MRSA) with an antibacterial efficiency of 98.5% under 15 min of US treatment, resulting in intracellular DNA damage and increased oxidative stress and disturbance of purine metabolism, tryptophan metabolism, and pantothenate and CoA biosynthesis of MRSA. Together with the toxin neutralization ability, the RBC-HNTM-MoS 2 successfully eliminates the bone infection and suppresses inflammation and bone loss. This work provides another strategy for developing an efficient sonosensitizer through piezoelectric-assisted sonocatalysis and enhancing US-propelling ability.

When you reach with your straw for the final drops of a milkshake, the liquid forms a train of plugs that flow slowly initially because of the high viscosity. They then suddenly rupture and are replaced with a rapid airflow with the characteristic slurping sound. Trains of liquid plugs also are observed in complex geometries, such as porous media during petroleum extraction, in microfluidic two-phase flows, or in flows in the pulmonary airway tree under pathological conditions. The dynamics of rupture events in these geometries play the dominant role in the spatial distribution of the flow and in determining how much of the medium remains occluded. Here we show that the flow of a train of plugs in a straight channel is always unstable to breaking through a cascade of ruptures. Collective effects considerably modify the rupture dynamics of plug trains: Interactions among nearest neighbors take place through the wetting films and slow down the cascade, whereas global interactions, through the total resistance to flow of the train, accelerate the dynamics after each plug rupture. In a branching tree of microchannels, similar cascades occur along paths that connect the input to a particular output. This divides the initial tree into several independent subnetworks, which then evolve independently of one another. The spatiotemporal distribution of the cascades is random, owing to strong sensitivity to the plug divisions at the bifurcations. microfluidics | respiratory flow T he motion of liquid plugs through a connected network of channels may involve many degrees of freedom evolving via a similarly large number of interactions: each immiscible interface introduces a degree of freedom into the problem owing to its ability to deform and to move, whereas each connecting branch between different areas introduces an interaction path that allows the flow in one region to influence the behavior in other areas of the network. The resulting flow pattern determines, among other things, how water or oil is extracted from porous media (1-3), the imbibition of paper (4, 5), and the stability of flow in a microfluidic device (6, 7).Liquid-gas two-phase flows also occur in the pulmonary airway tree, which is constantly coated with a thin liquid film. When the thickness of this film increases beyond some limit, plugs of liquid may form (8, 9) and therefore occlude the flow of air to the distal branches. Evidence of such behavior has been observed in pathologies ranging from asthma (10, 11) to cystic fibrosis (12). Furthermore, liquid plugs may be used as means to deliver medical treatment into the lung, e.g., in surfactant replacement therapy (13), and these plugs were observed to go through complex divisions, breaking and reforming before reaching their intended target (14).The structure of the lung as a branching binary tree has motivated many studies on the motion of gas-liquid flows into bifurcating channels (15)(16)(17)(18)(19)(20), with numerical work also taking into account the elasticity of the pulmonary walls, (e.g refs. ...

PurposeUnderstanding complex abdominal organ motion is essential for motion management in radiation therapy (RT) of abdominal tumors. This study investigates abdominal motion induced by respiration and peristalsis, during various time durations relevant to RT, using various CT and MRI techniques acquired under free breathing (FB) and breath hold (BH).MethodsA series of CT and MRI images acquired with various techniques under free breathing and/or breath hold from 37 randomly-selected pancreatic or liver cancer patients were analyzed to assess the motion in various time frames. These data include FB 4DCT from 15 patients (for motion in time duration of 5 sec), FB 2D cine-MRI from 4 patients (time duration of 1.7 min, 1 second acquisition time per slice), FB cine-MRI acquired using MR-Linac from 6 patients in various fractions (acquisition time is less than 0.6 seconds per slice), FB 4DMRI from 2 patients (time duration of 2 min), respiration-gated T2 with gating at the end expiration (time duration of 3–5 min), and BH T1 with multiphase dynamic contrast in acquisition times of 17 seconds for each of five phases (pre-contrast, arterial, venous, portal venous and delayed post-contrast) from 10 patients. Motions of various organs including gallbladder (GB) and liver were measured based on these MRI data. The GB motion includes both respiration and peristalsis, while liver motion is primarily respiration. By subtracting liver motion (respiration) from GB motion (respiration and peristalsis), the peristaltic motion, along with small residual motion, was obtained.ResultsFrom cine-MRI, the residual motion beyond the respiratory motion was found to be up to 0.6 cm in superior-inferior (SI) and 0.55 cm in anterior-posterior (AP) directions. From 2D cine-MRI acquired by the MR-Linac, different peristaltic motions were found from different fractions for each patient. The peristaltic motion was found to vary between 0.3–1 cm. From BH T1 phase images, the average motions that were primarily due to peristalsis movements were found to be 1.2 cm in SI, 0.7 cm in AP, and 0.9 cm in left-right (LR) directions. The average motions assessed from 4DCT were 1.0 cm in SI and 0.3 cm in AP directions, which were generally smaller than the motions assessed from cine-MRI, i.e., 1.8 cm in SI and 0.6 cm in AP directions, for the same patients. However, average motions from 4DMRI, which are coming from respiratory were measured to be 1.5, 0.5, and 0.4 cm in SI, AP, and LR directions, respectively.ConclusionThe abdominal motion due to peristalsis can be similar in magnitude to respiratory motion as assessed. These motions can be irregular and persistent throughout the imaging and RT delivery procedures, and should be considered together with respiratory motion during RT for abdominal tumors.

This study suggests that IMRT results in milder hematological toxicity than either 3DCRT or RapidARC. Dosimetric parameters were associated with the incidence of HT in cervical cancer patients who received concurrent chemoradiotherapies.