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Stem cell-based transplantation is a promising therapeutic approach for intervertebral disc degeneration (IDD). Current limitations of stem cells include with their insufficient cell source, poor proliferation capacity, low nucleus pulposus (NP)-specific differentiation potential, and inability to avoid pyroptosis caused by the acidic IDD microenvironment after transplantation. To address these challenges, embryo-derived long-term expandable nucleus pulposus progenitor cells (NPPCs) and esterase-responsive ibuprofen nano-micelles (PEG-PIB) were prepared for synergistic transplantation. In this study, we propose a biomaterial pre-modification cell strategy; the PEG-PIB were endocytosed to pre-modify the NPPCs with adaptability in harsh IDD microenvironment through inhibiting pyroptosis. The results indicated that the PEG-PIB pre-modified NPPCs exhibited inhibition of pyroptosis

Vortex electromagnetic waves (VEMWs) carrying orbital angular momentum (OAM) are promising to benefit the higher degree of freedom for inverse synthetic aperture radar (ISAR) imaging on account of their helical wavefront. For high‐speed targets, the ‘stop and go’ hypothesis is no longer valid. Thus, the intrapulse movement of the target will cause the broadening and shift of the one‐dimensional range profile and the blurring of the OAM eigenvalues coupling azimuth. This contribution proposes a high‐speed target imaging method for the VEMW ISAR. First, an OAM‐based ISAR imaging model for high‐speed targets is derived and the echo characteristics are analysed. Subsequently, in order to effectively estimate the ratio of the echo to correct the imaging result, an estimation method that takes into account the calculation speed and accuracy is proposed. On this basis, the target velocity distribution obtained under multiple echoes is analysed to improve the accuracy of the results. Finally, the range profile and azimuthal profile are reconstructed. Compared with the existing vortex electromagnetic imaging algorithm, the proposed method can effectively eliminate the influence of high‐speed motion on the range and azimuth profile. This work provides suggestions for the development of EM vortex ISAR imaging technology.

Background and objectivesThe high transmissibility of SARS-CoV-2 has exposed weaknesses in our infection control and detection measures, particularly in healthcare settings. Aerial sampling has evolved from passive impact filters to active sampling using negative pressure to expose culture substrate for virus detection. We evaluated the effectiveness of an active air sampling device as a potential surveillance system in detecting hospital pathogens, for augmenting containment measures to prevent nosocomial transmission, using SARS-CoV-2 as a surrogate.MethodsWe conducted air sampling in a hospital environment using the AerosolSenseTM air sampling device and compared it with surface swabs for their capacity to detect SARS-CoV-2.ResultsWhen combined with RT-qPCR detection, we found the device provided consistent SARS-CoV-2 detection, compared to surface sampling, in as little as 2 h of sampling time. The device also showed that it can identify minute quantities of SARS-CoV-2 in designated “clean areas” and through a N95 mask, indicating good surveillance capacity and sensitivity of the device in hospital settings.ConclusionActive air sampling was shown to be a sensitive surveillance system in healthcare settings. Findings from this study can also be applied in an organism agnostic manner for surveillance in the hospital, improving our ability to contain and prevent nosocomial outbreaks.

We propose a causal framework for decomposing a group disparity in an outcome in terms of an intermediate treatment variable. Our framework captures the contributions of group differences in baseline potential outcome, treatment prevalence, average treatment effect, and selection into treatment. This framework is counterfactually formulated and readily informs policy interventions. The decomposition component for differential selection into treatment is particularly novel, revealing a new mechanism for explaining and ameliorating disparities. This framework reformulates the classic Kitagawa-Blinder-Oaxaca decomposition in causal terms, supplements causal mediation analysis by explaining group disparities instead of group effects, and resolves conceptual difficulties of recent random equalization decompositions. We also provide a conditional decomposition that allows researchers to incorporate covariates in defining the estimands and corresponding interventions. We develop nonparametric estimators based on efficient influence functions of the decompositions. We show that, under mild conditions, these estimators are $\sqrt{n}$-consistent, asymptotically normal, semiparametrically efficient, and doubly robust. We apply our framework to study the causal role of education in intergenerational income persistence. We find that both differential prevalence of and differential selection into college graduation significantly contribute to the disparity in income attainment between income origin groups.

Four dinuclear osmium complexes have been constructed for antitumor phototherapy. The most potent Os4 has extremely high photothermal conversion capability under irradiation of an 808 nm low-power laser, targets mitochondria in human melanoma cells without nucleus affinity, and acts as an antitumor photothermal therapy agent

Topological quantum computation (TQC) is one of the most striking architectures that can realize fault-tolerant quantum computers. In TQC, the logical space and the quantum gates are topologically protected, i.e., robust against local disturbances. The topological protection, however, requires rather complicated lattice models and hard-to-manipulate dynamics; even the simplest system that can realize universal TQC--the Fibonacci anyon system--lacks a physical realization, let alone braiding the non-Abelian anyons. Here, we propose a disk model that can realize the Fibonacci anyon system, and construct the topologically protected logical spaces with the Fibonacci anyons. Via braiding the Fibonacci anyons, we can implement universal quantum gates on the logical space. Our proposal is platform-independent. As a demonstration, we implement a topological Hadamard gate on a logical qubit through a sequence of $15$ braiding operations of three Fibonacci anyons with merely $2$ nuclear spin qubits. The gate fidelity reaches 97.18% by randomized benchmarking. We further prove by experiment that the logical space and Hadamard gate are topologically protected: local disturbances due to thermal fluctuations result in a global phase only. Our work is a proof of principle of TQC and paves the way towards fault-tolerant quantum computation., 8 pages, 4 figures

Noise is ubiquitous in real quantum systems, leading to non-Hermitian quantum dynamics, and may affect the fundamental states of matter. Here we report in an experiment a quantum simulation of the two-dimensional non-Hermitian quantum anomalous Hall (QAH) model using the nuclear magnetic resonance processor. Unlike the usual experiments using auxiliary qubits, we develop a stochastic average approach based on the stochastic Schrödinger equation to realize the non-Hermitian dissipative quantum dynamics, which has advantages in saving the quantum simulation sources and simplifying the implementation of quantum gates. We demonstrate the stability of dynamical topology against weak noise and observe two types of dynamical topological transitions driven by strong noise. Moreover, a region where the emergent topology is always robust regardless of the noise strength is observed. Our work shows a feasible quantum simulation approach for dissipative quantum dynamics with stochastic Schrödinger equation and opens a route to investigate non-Hermitian dynamical topological physics.

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Chicken manure is one of the popular organic fertilizers used in vegetable farming in Malaysia. Chicken manure is divided into two types, namely broiler chicken manure (BCM) and layer chicken manure (LCM). The effectiveness of these chicken manures is often questionable due to the different method of raising broilers and layers. Therefore, the present study was carried out to determine the effect of the broiler and layer chicken manures on the growth of choy sum (Brassica chinensis L. var. parachinensis), a common farmed leafy vegetable in the country. This study was carried out in the Agricultural Park of Universiti Tunku Abdul Rahman (Perak Campus), Malaysia from February to May 2019. Randomized Complete Block Design (RCBD) methods were used in this study. The chicken manures were composted for roughly 2 months before the experiment. There was no significant difference in the dry weight, plant height and root length of the choy sum treated with either BCM or LCM. Although the choy sum treated with BCM has a higher fresh weight (177.53 g) as compared to that of LCM (134.64 g), this may be due to the natural fluctuation of water content within the plants. Therefore, the results of the present study show that both the chicken manure has a similar effect on the growth of choy sum. The authors recommend further studies on the chemical composition and optimization of chicken manure application in enhancing the growth and yields of leafy vegetables.

Herring and mackerel are two of the most important pillars of Scottish fisheries. In recent years, global warming has caused a gradual rise in ocean temperatures. In order to survive and reproduce, herring and mackerel populations will migrate. This will have a huge impact on Scotland’s fisheries. Therefore, we need to predict the relocation of fish stocks in advance, make timely adjustments to the fishing range, and minimize the loss of the fishing industry. In this article, we subdivide the research target sea area into 39 regions, establish the optimal SARIMA model for each region based on the collected seawater temperature time series data, and take region 13 and region 15 as examples to fit the ARIMA (3, 3, 1) (1, 2, 1) and ARIMA (2, 3, 1) (0, 2, 1) models with a period of 12. The results show that the SARIMA model fits well in all regions and predicts the temperature changes in the studied sea area from 2021 to 2050. Finally, according to the predicted sea temperature in different periods, the migration position of the fish school is predicted.

Palm oil production results in many valuable products, but it also generates agricultural wastes such as empty fruit bunch (EFB). EFB composting usually produces nutrient-enriched bio-fertilisers and thus, able to help in reducing the chemical fertilisers applied. Most conventional vegetable farmers in Malaysia solely depend on chemical fertilisers in crop production. However, the intensive use of chemical fertilisers has led to various side effects. Thus, this study was to determine the effect on the growth of choy sum by reducing the dosage of chemical fertiliser with EFB compost as soil amendments. Randomized Complete Block Design (RCBD) methods were used in this study. The fresh weight, dry weight and plant height of the choy sum were found to be not significantly different among all the treatments (T1 – T4) and positive control. This study found that T4 with 30% lesser chemical fertiliser applied showed no significant growth difference with the rest of the treatments indicating that EFB may have the ability to help in reducing chemical fertiliser usage in the growth of choy sum. Further study is recommended as this will help in better EFB waste management and lowering the cost of production for local vegetables.

Organic molybdenum (e.g., molybdenum dialkyldithiocarbamate, Mo-DTC) is a typical additive for liquid lubricants which can produce a significant anti-wear role with only a minor addition. I...

Nowadays, frequent pattern mining (FPM) on large graphs receives increasing attention, since it is crucial to a variety of applications, e.g., social analysis. Informally, the FPM problem is defined as finding all the patterns in a large graph with frequency above a user-defined threshold. However, this problem is nontrivial due to the unaffordable computational and space costs in the mining process. In light of this, we propose a cost-effective approach to mining near-optimal top-k patterns. Our approach applies a "level-wise" strategy to incrementally detect frequent patterns, hence is able to terminate as soon as top-k patterns are discovered. Moreover, we develop a technique to compute the lower bound of support with smart traverse strategy and compact data structures. Extensive experimental studies on real-life and synthetic graphs show that our approach performs well, i.e., it outperforms traditional counterparts in efficiency, memory footprint, recall and scalability.

A four-stranded scaffold of nucleic acids termed G-quadruplex (G4) has found growing applications in nano- and biotechnology. Propeller loops are a hallmark of the most stable intramolecular parallel-stranded G4s. To date, propeller loops have been observed to span only a maximum of three G-tetrad layers. Going beyond that would allow creation of more stable scaffolds useful for building robust nanodevices. Here we investigate the formation of propeller loops spanning more than three layers. We showed that native nucleotide sequences are incompatible to-wards this goal, and we identified synthetic non-nucleotide linkers that form propeller loop across four layers. With the established linkers, we constructed a four-layered intramolecular parallel-stranded G4, which exhibited ultra-high thermal stability. Control on loop design would augment the toolbox towards engineering of G4-based nano-scaffolds for diverse applications. National Research Foundation (NRF) Submitted/Accepted version This work was supported by Singapore National Research Foundation Investigatorship (NRF-NRFI2017-09) and Nanyang Technological University grants to A.T.P.

Environment perception is one of the most critical technology of intelligent transportation systems (ITS). Motion interaction between multiple vehicles in ITS makes it important to perform multi-object tracking (MOT). However, most existing MOT algorithms follow the tracking-by-detection framework, which separates detection and tracking into two independent segments and limit the global efficiency. Recently, a few algorithms have combined feature extraction into one network; however, the tracking portion continues to rely on data association, and requires complex post-processing for life cycle management. Those methods do not combine detection and tracking efficiently. This paper presents a novel network to realize joint multiobject detection and tracking in an end-to-end manner for ITS, named as global correlation network (GCNet). Unlike most object detection methods, GCNet introduces a global correlation layer for regression of absolute size and coordinates of bounding boxes, instead of offsetting predictions. The pipeline of detection and tracking in GCNet is conceptually simple, and does not require complicated tracking strategies such as non-maximum suppression and data association. GCNet was evaluated on a multi-vehicle tracking dataset, UA-DETRAC, demonstrating promising performance compared to state-of-the-art detectors and trackers.

A central question in sensory neuroscience is how neurons represent complex natural stimuli. This process involves multiple steps of feature extraction to obtain a condensed, categorical representation useful for classification and behavior. It has previously been shown that central auditory neurons in the starling have composite receptive fields composed of multiple features when probed with conspecific songs. Whether this property is an idiosyncratic characteristic of songbirds, a group of highly specialized vocal learners, or a generic characteristic of central auditory systems in different animals is, however, unknown. To address this question, we have recorded responses from auditory cortical neurons in mice, and characterized their receptive fields using mouse ultrasonic vocalizations (USVs) as a natural and ethologically relevant stimulus and pitch-shifted starling songs as a natural but ethologically irrelevant control stimulus. We have found that auditory cortical neurons in the mouse display composite receptive fields with multiple excitatory and inhibitory subunits. Moreover, this was the case with either the conspecific or the heterospecific vocalizations. We then trained the sparse filtering algorithm on both classes of natural stimuli to obtain statistically optimal features, and compared the natural and artificial features using UMAP, a dimensionality-reduction algorithm previously used to analyze mouse USVs and birdsongs. We have found that the receptive-field features obtained with the mouse USVs and those obtained with the pitch-shifted starling songs clustered together, as did the sparse-filtering features. However, the natural and artificial receptive-field features clustered mostly separately. These results indicate that composite receptive fields are likely a generic property of central auditory systems in different classes of animals. They further suggest that the quadratic receptive-field features of the mouse auditory cortical neurons are natural-stimulus invariant.

Pipe clamping mattresses (PCMs) are a relatively new system for providing anchoring force to pipelines, to mitigate offshore flowline ‘walking’. They represent a cost-effective and highly efficient alternative to anchor piles, rock dump and conventional concrete mattresses. The system comprises a hinged concrete structure that clamps onto a section of laid pipeline, with concrete ballast logs securing the clamping action – with the benefit that 100% of the submerged weight of the PCM contributes to axial friction. PCMs have been applied successfully to one deepwater project, but performance data showing the influence of soil type, and allowing a general design framework to be established, has not yet been available. This paper addresses this gap by investigating the performance of PCMs through three series of centrifuge tests, supported by three Operators. Each series comprises tests on a different reconstituted deepwater soil as follows: (a) West African clay; (b) Gulf of Mexico clay; and (c) carbonate silty sand. In each test, a scaled pipeline is installed in-flight and cycled axially to represent its prior operating life. Scaled PCM models and ballast units are then installed onto the pipe in-flight, mimicking the use of PCMs to mitigate pipeline walking during operation. After installation of the PCMs, further axial cycles are applied, with the system settlement and changes in axial resistance and excess pore pressure measured. The paper shows the performance and applicability of PCMs for a range of soil types, highlighting variations in axial resistance and settlement. The suite of results will help to calibrate design tools for industry, removing unnecessary conservatism and enabling an optimised pipeline anchoring solution to be designed. Key results are equivalent friction factors for the combined pipe-PCM system and PCM settlement, which both show behaviour dependent on soil type. In the clay soils, friction increases significantly over time due to ‘consolidation hardening’. This provides validation of an important effect that has only recently been recognised in pipeline design. In contrast, hardening behavior is not evident in silty sand – although the study suggests there is potential for increasing resistance associated with settlement, which appears to mobilize additional (wedging) stress around the pipeline. Upon PCM installation, the pipelines embed further due to the added weight. Additional settlement occurs during cycling of the system, due to immediate soil deformation and consolidation-related compression. The magnitude of embedment is greater for the clay soils, but in all cases does not cause the clamping action to release. Overall, the efficiency of the PCM system in providing a high level of anchoring force per unit weight placed on the seabed is confirmed. Long term anchoring forces in the range 50-100% of the submerged weight of the PCM are demonstrated. This is several times more efficient than the commonly used alternative of a rock berm.

This paper describes the continuous improvement efforts to manage the integrity status of the Southern North Sea subsea pipeline system in the context of free spanning. The dynamic free-spanning threat is typically attributed to a mobile seabed. Current and wave action are constantly moving and eroding sediment by means of sand wave migration and scouring. It can lead to a fluctuation in span characteristics with respect to span length, span height and location over time. It makes pipeline integrity demonstration and spans remediation challenges. Focus areas include (1) identifying regions where operational pipelines are susceptible to critical span formation (2) understanding the broader context of seabed mobility, supported by several years of multibeam echo sound and met ocean data (3) risk-ranking & criticality of span formation (4) developing simplified calculation tool that allows fatigue damage to be estimated and accumulated for every location along the pipeline, conservatively (5) optimising and incorporating risk/event-based survey requirements (6) identification of suitable remediation solutions and developing a decision flow chart to facilitate selection of fit for purpose remediation solutions, with respect to span configuration and the surrounding seabed features. The outcome has improved the robustness of span management, reduced “reactive” span remediation activities, and allowed application of sound technical theory to allocate pipeline traffic light integrity status regarding the observed free spans.

This paper describes a multi-pronged continuous improvement effort to manage the spans of a deep-water pipeline, where even without wave action, the currents are strong enough to move sediments, leading to constantly changing spans. The effort includes: (1) using strakes rather than intermediate supports to suppress VIV, since the latter proved not to be a long-term solution, (2) using partial rather than full strake coverage of spans and developing tools to quantify the level of strake coverage that is required, (3) improving estimates of soil stiffness and damping, and tools to handle amplitude-dependent soil stiffness and damping, (4) performing pluck tests of the operating pipeline by pulling it laterally at midspan with the ROV until a weak link connecting the ROV to the pipe breaks, whereupon the resulting motion of the pipe is recorded with accelerometers, (5) developing tools that allow fatigue damage to be estimated and accumulated for every location along the pipeline (6) sponsoring a joint industry program by DNVGL to quantify the effect of seabed proximity and trench effects on VIV. This paper provides an overview of these activities, with emphasis on recent results and new assessment tools and methods developed and their validation covering items (2–4) above.

To survive, animals have to quickly modify their behaviour when the reward changes. The internal representations responsible for this are updated through synaptic weight changes, mediated by certain neuromodulators conveying feedback from the environment. In previous experiments, we discovered a form of hippocampal Spike-Timing-Dependent-Plasticity (STDP) that is sequentially modulated by acetylcholine and dopamine. Acetylcholine facilitates synaptic depression, while dopamine retroactively converts the depression into potentiation. When these experimental findings were implemented as a learning rule in a computational model, our simulations showed that cholinergic-facilitated depression is important for reversal learning. In the present study, we tested the model’s prediction by optogenetically inactivating cholinergic neurons in mice during a hippocampus-dependent spatial learning task with changing rewards. We found that reversal learning, but not initial place learning, was impaired, verifying our computational prediction that acetylcholine-modulated plasticity promotes the unlearning of old reward locations. Further, differences in neuromodulator concentrations in the model captured mouse-by-mouse performance variability in the optogenetic experiments. Our line of work sheds light on how neuromodulators enable the learning of new contingencies., Author summary Reversal learning likely involves changes in synaptic connections, a neural mechanism known as synaptic plasticity, so old information can be updated. We previously discovered that acetylcholine, an important neuromodulator in the brain, changes synaptic connections in a way that favours reversal learning. Specifically, acetylcholine weakens active synapses in brain slices, but these synapses can later be strengthened by a reward signal. Based on this result in slices, we used a computational model to propose a behavioural function for the action of acetylcholine on synaptic connections. In the model, acetylcholine would weaken synaptic connections associated with an old reward, allowing an agent to quickly learn a new reward location. We tested this hypothesis here by silencing acetylcholine neurons in mice while they navigated a maze for food rewards. These animals were able to learn the location of the first food reward, but were impaired when the reward was shifted to a new location. The behavioural results of this study suggest that acetylcholine indeed facilitates reversal learning, which the computational model attributes to a weakening of synaptic connections that do not lead to reward. Taken together, our experimental and computational work show how synaptic strength changes, gated by neuromodulators, affect learning behaviour.

The uv-faceting imaging is one of the widely used large field of view imaging technologies, and will be adopted for the data processing of the low-frequency array in the first stage of the Square Kilometre Array (SKA1). Due to the scale of the raw data of SKA1 is unprecedentedly large, the efficiency of data processing directly using the original uv-faceting imaging will be very low. Therefore, a uv-faceting imaging algorithm based on the MPI (Message Passing Interface)+OpenMP (Open Multi-Processing) and a uv-faceting imaging algorithm based on the MPI+CUDA (Compute Unified Device Architecture) are proposed. The most time-consuming data reading and gridding in the algorithm are optimized in parallel. The verification results show that the results of the proposed two algorithms are basically consistent with that obtained by the current mainstream data processing software CASA (Common Astronomy Software Applications), which indicates that the proposed two algorithms are basically correct. Further analysis of the accuracy and total running time shows that the MPI+CUDA method is better than the MPI+OpenMP method in both the correctness rate and running speed. The performance test results show that the proposed algorithms are effective and have certain extensibility.

Carbohydrate digestibility is a key determinant for elevated postprandial hyperglycemia (PPHG). Apart from dietary restrictions, one of the strategies to reduce PPHG is to limit the activity of carbohydrate digestive enzymes within the gastrointestinal tract in order to reduce monosaccharide absorption rates. The present work aimed to assess the inhibitory capabilities of digestive enzymes (e.g., α-glucosidase and α-amylase) by anthoxanthins when used independently, in combination with acarbose, or with a different anthoxanthin. Our results showed that quercetin, myricetin, and luteolin presented lower IC

Background Lineage 4 of Mycobacterium tuberculosis complex (MTBC), mainly epidemic in Europe and Americas, presents in high proportions in South China and is believed to enter China around the 13th century, when the important human migratory events of the Maritime Silk Road and “Huguang Filling Sichuan” population migration happened in China. This study was to explain the coincidence of these two events with lineage 4’s high proportion in South China. Methods Based on the spatial interpolation analysis of the genotyping data of 25,575 MTBC isolates, the distribution of lineage 4 was compared with that of targeted surname populations and the Maritime Silk Road’s main ports. Results The results showed that lineage 4 distribution in China could be mapped to the regions affected by “Huguang Filling Sichuan” population migration; while the distribution of lineage 4’s two sub-lineages in Asia, Europe, Africa and Oceania could be best explained by the Maritime Silk Road. Conclusion Our results suggest that these two events might pose a crucial shared influence, leading to the greater incidence of lineage 4 in South China. And this may contribute to our better understanding of the prevailing tuberculosis landscape in China and facilitate the epidemiological investigations and tracking of emerging MTBC clones.

As a high-yielding forage grass, Phalaris arundinacea widely distributed in the Qinghai-Tibet Plateau region of China. To explore physiological and molecular response mechanism of Phalaris arundinacea under waterlogging, we analyzed the biomass and physiological indexes of three locally grown strains under the submerged condition of 10 cm. The material Z0611 showed the strongest waterlogging resistance while the YS showed the weakest performance. Transcriptome sequencing analysis demonstrated that the YS and Z0611 had 17010 and 7566 differently expression genes (DEGs), respectively, which were mainly concentrated in the metabolic process, cell, ribosome, phenylpropanoid biosynthesis pathway in GO and KEGG databases. We also identified a large number of genes involved in carbohydrate metabolism, hormone signaling regulation, transcription factors, antioxidant system, and ethylene signaling. Our research may provide a scientific basis for the restoration of wetland environment on the Qinghai-Tibet Plateau, and lay a foundation for further exploration of the waterlogging resistance genes of Phalaris arundinacea and breeding of new strains resistant with waterlogging stress.

Multi-object tracking (MOT) has made great progress in recent years, but there are still some problems. Most MOT algorithms follow tracking-by-detection framework, which separates detection and tracking into two independent parts. Early tracking-by-detection algorithms need to do two feature extractions for detection and tracking. Recently, some algorithms make the feature extraction into one network, but the tracking part still relies on data association and needs complex post-processing for life cycle management. Those methods do not combine detection and tracking well. In this paper, we present a novel network to realize joint multi-object detection and tracking in an end-to-end way, called Global Correlation Network (GCNet). Different from most object detection methods, GCNet introduces the global correlation layer for regression of absolute size and coordinates of bounding boxes instead of offsets prediction. The pipeline of detection and tracking by GCNet is conceptually simple, which does not need non-maximum suppression, data association, and other complicated tracking strategies. GCNet was evaluated on a multi-vehicle tracking dataset, UA-DETRAC, and demonstrates promising performance compared to the state-of-the-art detectors and trackers., Comment: 9 pages, 5 figures, under review

The car-free carrier platform is a product of the rapid development of the modern logistics industry and has a vital strategic value for promoting the construction of a country’s comprehensive transportation. However, due to the unreasonable platform pricing model, the industry is currently in a bottleneck period. In order to solve this problem, we established a gray correlation model to calculate the degree of correlation between each characteristic index and platform pricing based on the massive historical transaction data of a certain platform and performed K-means clustering on the results to discover the main factors affecting platform pricing. Based on the abovementioned results, we created a pricing optimization model based on the BP neural network, with the structure of 8-13-1 to predict the freight pricing of the order and test the prediction results. The test shows that the goodness of fit (R2) of the predicted value is close to 1, and the prediction error range is less than 3.7%, which proves the accuracy and effectiveness of the BP neural network model and provides an effective reference for the optimization of the pricing model of the car-free carrier platform.

Helical strakes can suppress vortex-induced vibrations (VIVs) in pipelines spans and risers. Pure in-line (IL) VIV is more of a concern for pipelines than for risers. To make it possible to assess the effectiveness of partial strake coverage for this case, an important gap in the hydrodynamic data for strakes is filled by the reported IL forced-vibration tests. Therein, a strake-covered rigid cylinder undergoes harmonic purely IL motion while subject to a uniform “flow” created by towing the test rig along SINTEF Ocean's towing tank. These tests cover a range of frequencies, and amplitudes of the harmonic motion to generate added-mass and excitation functions are derived from the in-phase and 90 deg out-of-phase components of the hydrodynamic force on the pipe, respectively. Using these excitation- and added-mass functions in VIVANA together with those from experiments on bare pipe by Aronsen (2007 “An Experimental Investigation of In-Line and Combined In-Line and Cross-Flow Vortex Induced Vibrations,” Ph.D. thesis, Norwegian University of Science and Technology, Trondheim, Norway.), the IL VIV response of partially strake-covered pipeline spans is calculated. It is found that as little as 10% strake coverage at the optimal location effectively suppresses pure IL VIV.

A novel solution to mitigate pipeline walking, namely the use of pipe-clamping mattresses (PCMs), was first developed for the Malampaya project (Frankenmolen et al. 2017). Comprising a hinged concrete structure designed to clamp onto a section of pipeline, and supporting (post-installed) ballast weight that is transferred directly to the pipeline, PCMs are considered a highly efficient alternative to more traditional solutions such as rock dump or concrete mattress. The original PCM geotechnical design was based primarily on analyses extrapolated from pipeline-seabed interaction, supported by a standard suite of classification and interface tests. Physical model testing was not performed. While observations (taken since installation) show that the PCMs have effectively mitigated pipeline walking in the seabed conditions at Malampaya, their performance in other soil types has not been investigated. To provide further evidence on the effectiveness of PCMs, and investigate their performance over time, a series of centrifuge tests were performed in a soil sample representative of deep-water Gulf of Mexico conditions. In each test, a model representing the PCM was installed on the pipeline section, which was then subjected to cyclic axial displacement. Settlement of the pipeline-PCM system, as well as changes in axial resistance, were directly measured and are reported in this paper.

Key uncertainties in the assessment of subsea pipeline spans for fatigue due to vortex-induced vibrations (VIV) are the effective axial force, the soil spring stiffness, and the soil damping. To reduce these uncertainties, pluck tests have been carried out, to determine the natural frequency and damping of single and multiple spans. These are carried out by pulling the span laterally at midspan with the ROV, until a 6mm or 8mm PP rope that serves as a weak link in the connection from the pipeline and the ROV breaks. The free vibrations resulting from this pluck are measured with accelerometers attached to the pipeline. The paper presents selected results from these tests and their interpretation in terms modal frequencies and damping ratios. Already at the achieved amplitudes of vibration of up to about 0.01D, the results already show considerable nonlinearity and inelasticity that is thought to come from the soil supporting the pipe at the shoulders of the span, and can be captured in FE models by making the soil springs nonlinear and inelastic.

The detection of topological phases of matter has become a central issue in recent years. Conventionally, the realization of a specific topological phase in condensed matter physics relies on probing the underlying surface band dispersion or quantum transport signature of a real material, which may be imperfect or even absent. On the other hand, quantum simulation offers an alternative approach to directly measure the topological invariant on a universal quantum computer. However, experimentally demonstrating high-dimensional topological phases remains a challenge due to the technical limitations of current experimental platforms. Here, we investigate the three-dimensional topological insulators in the AIII (chiral unitary) symmetry class, which yet lack experimental realization. Using the nuclear magnetic resonance system, we experimentally demonstrate their topological properties, where a dynamical quenching approach is adopted and the dynamical bulk-boundary correspondence in the momentum space is observed. As a result, the topological invariants are measured with high precision on the band-inversion surface, exhibiting robustness to the decoherence effect. Our Letter paves the way toward the quantum simulation of topological phases of matter in higher dimensions and more complex systems through controllable quantum phases transitions.

The detection of topological phases of matter becomes a central issue in recent years. Conventionally, the realization of a specific topological phase in condensed matter physics relies on probing the underlying surface band dispersion or quantum transport signature of a real material, which may be imperfect or even absent. On the other hand, quantum simulation offers an alternative approach to directly measure the topological invariant on a universal quantum computer. However, experimentally demonstrating high-dimensional topological phases remains a challenge due to the technical limitations of current experimental platforms. Here, we investigate the three-dimensional topological insulators in the AIII (chiral unitary) symmetry class which yet lack experimental realization. Using the nuclear magnetic resonance system, we experimentally demonstrate their topological properties, where a dynamical quenching approach is adopted and the dynamical bulk-boundary correspondence in the momentum space is observed. As a result, the topological invariants are measured with high precision on the band-inversion surface, exhibiting robustness to the decoherence effect. Our work paves the way towards the quantum simulation of topological phases of matter in higher dimensions and more complex systems through controllable quantum phases transitions., Comment: 6 pages for main text+ 5 pages for supplementary information

This study aims to explore the factors influencing the success rate of the microdissection testicular sperm extraction (Micro-TESE) in patients with nonobstructive azoospermia (NOA) and cryptorchidism. Clinical data of 162 patients with cryptorchidism who underwent Micro-TESE due to infertility from December 2015 to May 2020 in the First Affiliated Hospital of Nanjing Medical University were analyzed retrospectively. In the univariate analysis, significant differences in the age of patient at the time of orchidopexy (median [interquartile range, IQR]: 7.0 [4.0-11.0] years vs 11.5 [9.0-14.5] years, P0.001), interval between orchidopexy and Micro-TESE (mean ± standard deviation: 17.5 ± 5.0 years vs 14.4 ± 4.4 years, P0.001), severity of cryptorchidism (unilateral [62.8%] vs bilateral [31.6%], P0.001; location of cryptorchidism, intra-abdominal [27.3%] vs inguinal [44.8%] vs suprascrotal [66.7%], P0.001), volume of the dominant testis (median [IQR]: 17.00 [15.00-19.00] ml vs 14.50 [11.75-16.25] ml, P0.001), and levels of follicle-stimulating hormone (FSH; P = 0.004) and testosterone (P = 0.006) were observed between the successful and failed sperm extraction groups. After conducting the multivariate analysis, four of these factors, including unilateral/bilateral cryptorchidism (P0.001), location of cryptorchidism (P = 0.032), age of orchidopexy (P0.001), and dominant testicular volume, were adopted in the clinical prediction model to evaluate preoperatively the success rate of Micro-TESE for patients with NOA and cryptorchidism. The likelihood of successful sperm retrieval by Micro-TESE in men with NOA and cryptorchidism increased in patients with mild forms of cryptorchidism.

Behavioral profiling of players in digital games is a key challenge in game analytics, representing a particular challenge in Open-World Games. These games are characterized by large virtual worlds and few restrictions on player affordances. In these games, incorporating the spatial and temporal dimensions of player behavior is necessary when profiling behavior, as these dimensions are important to the playing experience. We present analyses that apply cluster analysis and the DEDICOM decompositional model to profile the behavior of more than 5,000 players of the major commercial title Just Cause 2 integrating both spatio-temporal trails and behavioral metrics. The application of DEDICOM to profile the spatio-temporal behavior of players is demonstrated for the purpose of analysing the entire play history of Just Cause 2 players, but also for the more detailed analysis of a single mission. This showcases the applicability of spatio-temporal profiling to condense player behavior across large sample sizes, across different scales of investigation. The method presented here provides a means to build profiles of player activity in game environments with high degrees of freedom across different scales of analysis - from a small segment to the entire game.

Excitation and added mass functions determined from forced vibration tests of a rigid cylinder undergoing harmonic motion in the flow are used in the semi-empirical software VIVANA to predict the VIV response of pipelines. An advantage of this approach, as opposed to the more-commonly-used response function approach, is that it can account for changing conditions along the length of the pipe, like changing current velocity, seabed proximity, and/or pipe diameter. This makes it useful for pipelines as well as for risers when such changes occur. Further, for pipelines, travelling wave effects play less of a role than for risers, so the VIVANA approach can be simplified by assuming the phase angle of the harmonic response is constant along the span. The interactions between cross-flow and in-line response that complicate the prediction of cross-flow VIV by the excitation function approach, do not arise for pure inline VIV. For the latter case, using the pure in-line forced vibration test data of Aronsen (2007), it is found that both VIVANA approach and simplified ‘SIVANA’ approach thereof predict VIV amplitudes consistent with experiments on flexible pipe (Ormen Lange umbilical VIV tests), and the DNVGL-RP-F105 response function for a range of structural and soil damping values. In a companion paper, this approach is applied partially strake-covered pipeline spans, to show that a relatively small fraction of well-placed strake coverage is enough to suppress in-line VIV.

Glutamine synthetase (GS), which catalyzes the production of glutamine, plays essential roles in most biological growth and biofilm formation, suggesting that GS may be used as a promising target for antibacterial therapy. We asked whether a GS inhibitor could be found as an anti-infective agent of Staphylococcus xylosus (S. xylosus). Here, computational prediction followed by experimental testing was used to characterize GS. Sorafenib was finally determined through computational prediction. In vitro experiments showed that sorafenib has an inhibitory effect on the growth of S. xylosus by competitively occupying the active site of GS, and the minimum inhibitory concentration was 4 mg/L. In vivo experiments also proved that treatment with sorafenib significantly reduced the levels of TNF-α and IL-6 in breast tissue from mice mastitis, which was further confirmed by histopathology examination. These findings indicated that sorafenib could be utilized as an anti-infective agent for the treatment of infections caused by S. xylosus.

A series of experiments is performed in which a strake-covered rigid cylinder undergoes harmonic purely in-line motion while subject to a uniform “flow” created by towing the test rig along SINTEF Ocean’s towing tank. These tests are performed for a range of frequencies and amplitudes of the harmonic motion, to generate added-mass and excitation functions are derived from the in-phase and 90° out-of-phase components of the hydrodynamic force on the pipe, respectively. Using these excitation- and added-mass functions in VIVANA together with those from experiments on bare pipe by Aronsen (2007), the in-line VIV response of partially strake-covered pipeline spans is calculated. It is found that as little as 10% strake coverage at the optimal location effectively suppresses pure in-line VIV. Further advantages of strakes rather than intermediate supports to suppress in-line VIV include: strakes are not affected by the scour which can lower an intermediate support (in addition to creating the span in the first place). Further they do not prevent self-lowering of the pipeline or act as a point of concentration of VIV damage as the spans to each side of the intermediate support grow again.

The atom manipulation technique based on scanning tunneling microscope refers to a method of relocating single atoms or molecules on a certain surface at atomic accuracy by using an atomically sharp tip, which is a unique and powerful tool for studying the quantum physics and prototype quantum devices on a nanometer scale. This technique allows us to build artificial structure atom-by-atom, thus some desired interesting quantum structures which are difficult to grow or fabricate by conventional methods could be realized, and unique quantum states, spin order, band structure could be created by the fine tuning of the structural parameters like lattice constant, symmetry, periodicity, etc. Combined with nanosecond scale time domain electric measurement and autonomous control technique, the atom manipulation would be useful in exploring the atomic precision prototype quantum devices, and providing some valuable knowledge for future electronics. In this review, we introduce the atom manipulation technique and related milestone research achievements and latest progress of artificial quantum structures, including electronic lattices with exotic quantum states on Cu(111), quantum dots on III-V semiconductors, magnetic structures with tunable spin order, structures for quantum information storage and processing, prototype Boolean logic devices and single atom devices. The STM lithography and autonomous atom manipulation are discussed as well. With such improvements, this technique would play more important roles in developing the functional quantum devices in future.

In shallow waters, subsea pipelines can suffer fatigue damage from Vortex Induced Vibrations (VIV) by the combined effects of waves and currents. A full characterization of the joint probability distribution of waves and currents involves at least 5 variables, 2 for currents (magnitude and direction), and 3 for waves (significant wave height, mean wave direction, and wave period at the peak of the spectrum). In lieu of sufficient data to adequately characterize the associated joint probability density function, DNV GL in their “Recommended Practice” propose an approximation: Assume that the direction of current and wave effects is always the same, but for a given direction, waves and currents are assumed statistically independent. In this paper 28 years of hindcast data are used to test the accuracy of this colinearity approximation in the Sea of Okhotsk. Rather than attempting to estimate a joint probability density function in 5 variables, the span fatigue assessment is simply performed for the entire 28 years of the hindcast database to obtain an average rate of fatigue damage. It is found that this history-based approach can lead to fatigue damage rates that are much higher than those derived from the colinearity assumption. This non-conservatism of the colinearity assumption, arises for pipeline orientations for which both waves and currents can contribute strongly to the VIV response without being exactly colinear. It is concluded that caution is needed in using the colinearity assumption, but an update of the span assessment procedure should also address issues for which current assessment procedures are conservative, such as seabed proximity and trench effects, nonlinearity in the pipe-soil interaction, and the change in axial forces due to transverse displacements of the pipe, which are expected under extreme combined current and wave conditions, as envisioned on on-bottom stability design criteria.