An overview on nonlinear porous flow in low permeability porous media

AbstractThis paper gives an overview on nonlinear porous flow in low permeability porous media, reveals the microscopic mechanisms of flows, and clarifies properties of porous flow fluids. It shows that, deviating from Darcy's linear law, the porous flow characteristics obey a nonlinear law in a low-permeability porous medium, and the viscosity of the porous flow fluid and the permeability values of water and oil are not constants. Based on these characters, a new porous flow model, which can better describe low permeability reservoir, is established. This model can describe various patterns of porous flow, as Darcy's linear law does. All the parameters involved in the model, having definite physical meanings, can be obtained directly from the experiments

Iron-sulfur proteins are the major source of protein-bound dinitrosyl iron complexes formed in Escherichia coli cells under nitric oxide stress

Protein-bound dinitrosyl iron complexes (DNICs) have been observed in prokaryotic and eukaryotic cells under nitric oxide (NO) stress. The identity of proteins that bind DNICs, however, still remains elusive. Here we demonstrate that iron-sulfur proteins are the major source of protein-bound DNICs formed in Escherichia coli cells under NO stress. Expression of recombinant iron-sulfur proteins, but not proteins without iron-sulfur clusters, almost doubles the amount of protein-bound DNICs formed in E. coli cells after NO exposure. Purification of recombinant proteins from the NO-exposed E. coli cells further confirms that iron-sulfur proteins, but not proteins without iron-sulfur clusters, are modified, forming protein-bound DNICs. Deletion of the iron-sulfur cluster assembly proteins IscA and SufA to block the [4Fe-4S] cluster biogenesis in E. coli cells largely eliminates the NO-mediated formation of protein-bound DNICs, suggesting that iron-sulfur clusters are mainly responsible for the NO-mediated formation of protein-bound DNICs in cells. Furthermore, depletion of the chelatable iron pool in wild-type E. coli cells effectively removes iron-sulfur clusters from proteins and concomitantly diminishes the NO-mediated formation of protein-bound DNICs, indicating that iron-sulfur clusters in proteins constitute at least part of the chelatable iron pool in cells. © 2011 Elsevier Inc. All rights reserved

Sparse4D: Multi-view 3D Object Detection with Sparse Spatial-Temporal Fusion

Bird-eye-view (BEV) based methods have made great progress recently in multi-view 3D detection task. Comparing with BEV based methods, sparse based methods lag behind in performance, but still have lots of non-negligible merits. To push sparse 3D detection further, in this work, we introduce a novel method, named Sparse4D, which does the iterative refinement of anchor boxes via sparsely sampling and fusing spatial-temporal features. (1) Sparse 4D Sampling: for each 3D anchor, we assign multiple 4D keypoints, which are then projected to multi-view/scale/timestamp image features to sample corresponding features; (2) Hierarchy Feature Fusion: we hierarchically fuse sampled features of different view/scale, different timestamp and different keypoints to generate high-quality instance feature. In this way, Sparse4D can efficiently and effectively achieve 3D detection without relying on dense view transformation nor global attention, and is more friendly to edge devices deployment. Furthermore, we introduce an instance-level depth reweight module to alleviate the ill-posed issue in 3D-to-2D projection. In experiment, our method outperforms all sparse based methods and most BEV based methods on detection task in the nuScenes dataset

Sparse4D v3: Advancing End-to-End 3D Detection and Tracking

In autonomous driving perception systems, 3D detection and tracking are the two fundamental tasks. This paper delves deeper into this field, building upon the Sparse4D framework. We introduce two auxiliary training tasks (Temporal Instance Denoising and Quality Estimation) and propose decoupled attention to make structural improvements, leading to significant enhancements in detection performance. Additionally, we extend the detector into a tracker using a straightforward approach that assigns instance ID during inference, further highlighting the advantages of query-based algorithms. Extensive experiments conducted on the nuScenes benchmark validate the effectiveness of the proposed improvements. With ResNet50 as the backbone, we witnessed enhancements of 3.0\%, 2.2\%, and 7.6\% in mAP, NDS, and AMOTA, achieving 46.9\%, 56.1\%, and 49.0\%, respectively. Our best model achieved 71.9\% NDS and 67.7\% AMOTA on the nuScenes test set. Code will be released at \url{https://github.com/linxuewu/Sparse4D}

The Solar Activity Monitor Network – SAMNet

The Solar Activity Magnetic Monitor (SAMM) Network (SAMNet) is a future UK-led international network of ground-based solar telescope stations. SAMNet, at its full capacity, will continuously monitor the Sun’s intensity, magnetic, and Doppler velocity fields at multiple heights in the solar atmosphere (from photosphere to upper chromosphere). Each SAMM sentinel will be equipped with a cluster of identical telescopes each with a different magneto-optical filter (MOFs) to take observations in K I, Na D, and Ca I spectral bands. A subset of SAMM stations will have white-light coronagraphs and emission line coronal spectropolarimeters. The objectives of SAMNet are to provide observational data for space weather research and forecast. The goal is to achieve an operationally sufficient lead time of e.g., flare warning of 2–8 h and provide many sought-after continuous synoptic maps (e.g., LoS magnetic and velocity fields, intensity) of the lower solar atmosphere with a spatial resolution limited only by seeing or diffraction limit, and with a cadence of 10 min. The individual SAMM sentinels will be connected to their master HQ hub where data received from all the slave stations will be automatically processed and flare warning issued up to 26 h in advance

Efficacy and safety of Jianpishengsui for chemotherapy-related fatigue in patients with non-small cell lung cancer : study protocol for a randomized placebo-controlled clinical trial

BACKGROUND: Chemotherapy-related fatigue (CRF) is a common symptom in non-small cell lung cancer (NSCLC) patients. A Chinese herbal formula cream for oral application, called Jianpishengsui (JPSS), is extensively used in the First Affiliated Hospital of Guangzhou University of Chinese Medicine as an internal preparation for CRF and is associated with a promising response. Due to the lack of high-quality clinical evidence, a randomized placebo-controlled trial is required to assess the efficacy and safety of JPSS. METHODS/DESIGN: The efficacy and safety of JPSS herbal formula cream will be evaluated through a prospective, randomized, placebo-controlled trial conducted in the First Affiliated Hospital of Guangzhou University of Chinese Medicine. NSCLC patients with CRF will be randomized into two groups at a ratio of 1:1. Each group will receive either 15 g of the oral JPSS herbal formula cream or placebo twice a day from day 6 to day 20 during two courses of paclitaxel + platinum/docetaxel + platinum/pemetrexed + platinum (TP/DP/AP) chemotherapy. The primary endpoint is the difference in the degree of fatigue between baseline (the day before the start of the intervention) and day 42, which will be assessed by the Revised Piper Fatigue Scale score. The secondary endpoints are quality of life (measured by the 43-item European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Lung Cancer C43), Eastern Cooperative Oncology Group Performance Status, and Traditional Chinese Medicine syndrome score. The toxicity of the treatments will also be evaluated at the same time. All outcomes will be measured at baseline, day 6, day 21, and day 42 of the treatment. DISCUSSION: This randomized trial will investigate the efficacy and safety of JPSS applied for CRF in patients with NSCLC. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1900023451. Registered on 28 May 2019

Heterologous expression of Spathaspora passalidarum xylose reductase and xylitol dehydrogenase genes improved xylose fermentation ability of Aureobasidium pullulans

Abstract Background Aureobasidium pullulans is a yeast-like fungus that can ferment xylose to generate high-value-added products, such as pullulan, heavy oil, and melanin. The combinatorial expression of two xylose reductase (XR) genes and two xylitol dehydrogenase (XDH) genes from Spathaspora passalidarum and the heterologous expression of the Piromyces sp. xylose isomerase (XI) gene were induced in A. pullulans to increase the consumption capability of A. pullulans on xylose. Results The overexpression of XYL1.2 (encoding XR) and XYL2.2 (encoding XDH) was the most beneficial for xylose utilization, resulting in a 17.76% increase in consumed xylose compared with the parent strain, whereas the introduction of the Piromyces sp. XI pathway failed to enhance xylose utilization efficiency. Mutants with superior xylose fermentation performance exhibited increased intracellular reducing equivalents. The fermentation performance of all recombinant strains was not affected when glucose or sucrose was utilized as the carbon source. The strain with overexpression of XYL1.2 and XYL2.2 exhibited excellent fermentation performance with mimicked hydrolysate, and pullulan production increased by 97.72% compared with that of the parent strain. Conclusions The present work indicates that the P4 mutant (using the XR/XDH pathway) with overexpressed XYL1.2 and XYL2.2 exhibited the best xylose fermentation performance. The P4 strain showed the highest intracellular reducing equivalents and XR and XDH activity, with consequently improved pullulan productivity and reduced melanin production. This valuable development in aerobic fermentation by the P4 strain may provide guidance for the biotransformation of xylose to high-value products by A. pullulans through genetic approach

TS2: a realistic IEEE1588 time-synchronization simulator for mobile wireless sensor networks

This paper presents the development of a simulator, TS2 (time-synchronization simulator), for realistically simulating and studying the performance of the IEEE 1588 precise time protocol (PTP) in IEEE 802.15.4 (TI CC2420 chip)-based mobile wireless sensor networks (WSNs). The PTP has the advantage of achieving high time precision at a low cost. It was designed for a wired Ethernet with requirements of symmetric communication paths and accurate time stamping, which is difficult for the low-cost WSNs to meet, as WSNs suffer more from overwhelming transmission delay jitters. An analytic solution to the performance of the PTP in WSNs is not possible, and it is of importance to evaluate the performance by realistic simulation. Based on the open-source OMNeT++ simulation engine, a realistic simulator was developed to simulate the PTP in IEEE 802.15.4 networks. There are two main contributions and benefits of the developed simulator. (1) Reality and fidelity: the WSN node’s various layers (including radio channels and TI CC2420 chip), drifting oscillator clocks and PTPs are simulated realistically. The drifting clock is simulated at an adjustable and higher resolution. (2) Support to both hardware and software time stamping, and the time-stamping uncertainties, by using a separated modular time-stamping module. It also has other features (such as extendibility and code-reusability, mobile WSN nodes, scalability for multi-node, multi-hop simulation). Finally, to demonstrate the simulator’s application to evaluating a PTP-based clock correction algorithm, a direct servo clock adjustment algorithm (i.e., a P controller) for a TI CC2420-based WSN was simulated and its performance was analyzed