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In this paper, we consider a container leasing firm that has elementary and premium containers, which are downward substitutable and for use by elementary contract customers (ECCs), premium contract customers (PCCs), as well as walk-in customers (WICs). ECCs can be satisfied by elementary containers or premium ones at discounted prices while PCCs only accept premium containers. WICs can be satisfied by any type of container at different prices. The objective is to maximise the expected total rental revenue by managing its limited capacity. We formulate this problem as a discrete-time Markov Decision Process and show the submodularity and concavity of the value function. Based on this, we show that the optimal policy can be characterised by a series of rationing thresholds, a series of substitution thresholds and a priority threshold, all of which depend on the system states. We further give conditions under which the optimal policy can be simplified. Numerical experiments are conducted to show the impact of the substitution of two items on the revenue, to compare the performance of the optimal policy with those of the commonly used policies and to investigate the influence of arrival rates on the optimal policy. Last, we extend the basic model to consider different rental durations, ECCs’ acceptance behaviour and endogenous prices for WICs. This paper was accepted by Jayashankar Swaminathan, operations management. Funding: This work was supported by National Natural Science Foundation of China/Research Grants Council of Hong Kong Joint Research Scheme [Grant 71661167009, N_PolyU531/16], National Natural Science Foundation of China [Grants 72171016, 71831001], and British Academy\Leverhulme Small Research [Grant SRG19\190059]. This work was also supported by Zhejiang Shuren University Research [Grant KXJ0121605] and Beijing Logistics Informatics Research Base. Supplemental Material: The e-companion and data files are available at https://doi.org/10.1287/mnsc.2022.4425 .

There is an urgent demand for non-invasive and high compliance delivery systems of macromolecules for long-term therapy. However, oral administration of macromolecules is hindered by low permeability and instability in the gastrointestinal (GI) tract. Therefore, we developed a novel aptamer-modified liposomes (Apt-Lip) with M cell targeting for oral delivery of exenatide (EXT). Firstly, we optimized aptamers to M cells by Cell-SELEX and aptamer truncations. The selected aptamer T-M3 (Apt-T-M3) with high binding affinity (K

Corncob, as a sustainable biomass waste, is mainly composed of hemicellulose. Herein, on the basis of natural corncob as substrates, Fe/N co-doped porous carbon spheres were designed via a consecut...

Profust reliability analysis is investigated in this article. The main aim is to address problems with very small failure probabilities. First, a single-layer multimodal importance sampling (MMIS) ...

Evidence theory-based reliability analysis (ETRA) is investigated in this paper. To estimate the plausibility (Pl) and belief (Bel) measures of failure probability, the active learning method based on Kriging model for ETRA (ALK-ETRA) has been proposed. However, ALK-ETRA pays too much attention to rightly predicting the signs of performance function at points throughout the uncertain space. To minimize the waste of training points, an enhanced version of ALK-ETRA (En-ALK-ETRA) is proposed in this paper. Pl or Bel is determined by the sign associated with an individual joint focal element (JFE) rather than a single point. Based on this idea, a brand-new learning function and a novel stopping condition are proposed in En-ALK-ETRA. Aided by the new learning function, the most dangerous JFE in which the lower (or upper) bound of performance function has the largest probability of wrong sign prediction is identified. The added training point is chosen from the most dangerous JFE and thus the convergence speed of learning process is accelerated. In the new stopping condition, the number of JFEs where the minimum (or maximum) of performance function with wrong sign predictions is explicitly deduced and thus the error of ETRA can be estimated. The error of ETRA is real-time monitored and thus the learning process is timely terminated without accuracy sacrifice. The performance of the proposed method is demonstrated by six case studies.

Profust reliability analysis, in which the failure state of a load-bearing structure is assumed to be fuzzy, is investigated in this paper. A novel active learning method based on the Kriging model is proposed to minimize the number of function evaluations. The new method is termed ALK-Pfst. The sign of performance function at a given random threshold determines the profust failure probability. Therefore, the expected risk function at an arbitrary threshold is derived as the learning function of ALK-Pfst. By making full use of the prediction information of Kriging model, the prediction error of profust failure probability is carefully derived into a closed-form expression. Aided by the prediction error, the accuracy of Kriging model during the learning process can be monitored in real time. As a result, the learning process can be timely terminated with little loss of accuracy. Four examples are provided to demonstrate the advantages of the proposed method.

In this paper, premixed syngas-air flame propagating from the open end to the closed end were experimentally investigated. The effects of equivalence ratios, 0.8 ≤ Ф ≤ 1.2, and hydrogen volume fractions, 10% ≤ α(H2) ≤ 90%, on flame deformation and oscillation had been discussed in detail. The tulip-like flame was observed because of the large pressure gradient. Results indicate that the pressure wave plays an important role in the flame deformation and oscillation. The flame oscillates as hydrogen volume fraction varies. There are two oscillation modes. When the flame oscillates as mode Ⅰ, the flame first oscillates smoothly, then the oscillation is gradually enhanced, and finally the oscillation decays. The interaction of flame and pressure waves continuously stimulates the flame deformation and oscillation, finally the violent flame folding emerges in the later stage. When the flame oscillates as mode Ⅱ, the flame just oscillates violently in the early stage.

Premixed flame of stoichiometric syngas-air mixture with various hydrogen volume fractions, 10% ≤ X (H2) ≤ 90%, propagating in a duct with both ends open is experimentally investigated in this study. Two representative ignition locations, i.e., Ig-1, locating at the center of the duct, and Ig-2, locating at the right open end, are considered. Results show that the tulip flame is first attained in the duct with both ends open at 10% ≤ X (H2) ≤ 50% as the flame is ignited at Ig-1. However, the flame maintains the convex shape with the cellular structure on the flame surface as the flame is ignited at Ig-2. The cellular structure results from Darrieus-Landau instability, but the Darrieus-Landau instability cannot invert the convex flame front. The flame tip and pressure dynamics have been examined. When the flame is ignited at Ig-1, the flame oscillates violently, and the overpressure profiles oscillate as a Helmholtz-type. When the flame is ignited at Ig-2, the left flame front propagates in an atmospheric pressure with a nearly constant speed. The prominent flame acceleration and oscillation are not observed at Ig-2 because of lacking flame acoustic interaction. What's more, the characteristic time of flame propagation has been compared. The time tw is shorter while the time tp is longer than the calculated value, and the time te has been delayed by both open ends. The flame propagation process is moderated as the flame propagates in the duct with both ends open.

Soybean oil bodies (SOBs), a natural source of pre-emulsified oil, have important potential applications in food industry. In this study, SOBs were extracted from raw soybean milk at pH 5.0, 7.0, 8.0, 9.0 and 11.0. The pH 5.0-, 7.0- and 8.0-SOB contained extrinsic proteins (mainly 7S, 11S and γ-conglycinin) and oleosins (24 kDa, 18 kDa and 16 kDa), and pH 9.0-, 11.0-SOB only had oleosins. Extrinsic protein contents decreased from 83.9% at pH 5.0-SOB to 58.2% at pH 8.0-SOB, zeta potentials increased gradually from -21.7 mV to -14.67 mV and particle sizes decreased from 924 nm to 359 nm with increasing extraction pHs. In stomach digestion, oleosins of pH 5.0-, 7.0-, 8.0-SOB were hydrolyzed more rapidly than extrinsic proteins. All 24 kDa oleosins were hydrolyzed during 5 min, and 18 kDa oleosins were completely hydrolyzed at 30 min for all SOBs. Oleosins were hydrolyzed and produced15 kDa pepsin-resistant peptides. In addition, some 7S and 11S of pH 5.0-, 7.0-, 8.0-SOB resisted pepsin hydrolysis. For all SOB emulsions, zeta potentials decreased and the droplets sizes increased significantly (P 0.05) with the extension of gastric digestive time. The oil droplets of all SOB emulsions aggregated, and the coalescence of oil droplets more easily occurred in pH 9.0- and 11.0-SOB emulsions. During the intestinal phase, zeta potentials and diameters of the droplets decreased gradually, and the droplets of SOB emulsions dispersed according to the CLSM. FFA release rates of pH 5.0-, 7.0-, 8.0-SOB emulsions increased rapidly and then increased slowly, however, the release tendency of pH 9.0-, 11.0-SOB emulsions were opposite. Total FFA releases of pH 5.0-, 7.0-, 8.0-, 9.0-, 11.0-SOB emulsions were respectively 52.5%, 70.5%, 59%, 48.8%, 43.3% at 180 min. Therefore, the digestive behaviors of SOB emulsions extracted at different pHs were different. This study will provide guidance for SOB products.

Prokinetics and proton pump inhibitors are first-line drugs for functional dyspepsia (FD) patients. However, no available treatment is effective for most FD patients, and the pathogenesis is still unclear. The purpose of this study was to investigate the therapeutic effect of transcutaneous neuromodulation (TN) on FD and its potential mechanisms.Fifty-seven FD patients were enrolled in the study and randomly divided into 3 groups (TN Neiguan (PC6) group, TN Zusanli (ST36) group, and sham TN group) that received corresponding treatment respectively for 4 weeks. Then, all the patients enrolled received TN PC6 combined with ST36 treatment for another 4 weeks. Dyspepsia symptom questionnaire, Medical outcomes study item short form health survey (SF-36), Hospital Anxiety and Depression Scale were used to assess the severity of symptoms. Gastric accommodation, gastric emptying rate, and related parameters of electrogastrogram were used to assess the pathophysiological mechanism of FD. The possible gastrointestinal hormonal mechanism involved was assessed by detecting serum ghrelin, neuropeptide Y, and vasoactive intestinal peptide. The possible duodenal inflammation mechanism involved was assessed by detecting duodenal mucosa.TN treatment reduced the dyspepsia symptom score (P0.05) and improved the quality of life. After TN treatment, the gastric accommodation (P0.01), the gastric emptying rate (P0.01), and the percentages of preprandial (P0.05) and postprandial (P0.05) gastric slow waves (GSW) were increased. The proportions of preprandial (P0.05) and postprandial (P0.05) gastric electrical rhythm disorder were reduced. The double acupoint combination therapy further enhanced the therapeutic effect of single acupoint. In addition, the levels of ghrelin (P0.001) and neuropeptide Y (P0.001) were significantly increased, the level of vasoactive intestinal peptide (P0.001) was significantly decreased, and the total number of mast cells (P0.001) in the duodenal bulb was significantly decreased after double acupoints combination therapy.TN treatment significantly improves the dyspepsia symptoms of FD patients and their quality of life. TN treatment increases the percentage of normal GSW, reduces the proportion of gastric electrical rhythm disorder, and improves the gastric accommodation and gastric emptying rate. The therapeutic effect of TN may be caused by regulating gastrointestinal hormone secretion and alleviating local inflammatory responses in duodenum. In addition, the improvement of TN on GSW was closely related to the decrease of bradygastria.

There have been many studies concerning on the influence of obstacles on gas explosion, but the understanding of some phenomena is still not clear, such as explosion overpressure or the change of flame velocity with the position of obstacles. This work aims to figure out the coupling effects of obstacle position (L1, L2, L3 from near to far) and hydrogen volume fraction (φ) on syngas-air flame acceleration and overpressure variation in a closed duct. Detailed flame structure evolution in the acceleration process was visualized by a high-speed camera, and overpressure was recorded by pressure transducers. Results show that the effect of obstacles moving backward is not always monotonous on the flame acceleration, which affects the maximum flame speed and maximum overpressure. Such as when φ = 0.5, the flame acceleration that is reflected as the flame propagation speed normalized by the laminar flame speed, ranks as L2 > L3 > L1. Because the obstacles strengthened turbulence on the tulip- or distorted tulip-shaped flame in L2. While when φ = 0.1, the flame acceleration ranks as L1 > L2 > L3 since the effect of turbulence is reduced. It is found that maximum overpressure is related to both flame acceleration and local overpressure. Local overpressure is the transient overpressure before the flame front touches obstacles. Obstacles moving backward is beneficial for local overpressure accumulation. Hence, the maximum overpressure increases with obstacle position moving backward when φ ≥ 0.1. This study clarifies the role of obstacle position and hydrogen volume fraction on flame acceleration, which may help to guide the application of syngas in a complex environment.

A novel domino reaction from benzaldehydes and 2-acetylfuran/2-acetylthiophene with sodium sulfide was developed to synthesize a series of tetrahydrothiopyran (THTP) derivatives. The reaction proceeded well to construct a tetrahydrothiopyran ring and five new bonds in one step. A mechanism is proposed, involving a stepwise Aldol/double Michael addition/Aldol (AMMA) reaction cascade. In this transformation, sodium sulfide acts as a nucleophile and base. This method is characterized by transition-metal-free, commercially available starting materials and mild reaction conditions.

In this study, we investigated the relaxation effect and mechanisms of patchouli alcohol (PA) on rat corpus cavernosum. Corpus cavernosum strips were used in organ baths for isometric tension studies. The results showed that PA demonstrated concentration-dependent relaxation effect on rat corpus cavernosum. The relaxant response to PA was not influenced by tetrodotoxin and atropine while it was significantly inhibited by removal of endothelium. L-NG-nitroarginine methyl ester (L-NAME, a nitric oxide synthase inhibitor) or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, a soluble guanylate cyclase inhibitor) significantly inhibited relaxation response to PA, whereas indomethacin (COX inhibitor) had no effect on PA-induced relaxation. The treatment of endothelium-deprived corpus cavernosum with several potassium channel blockers including tetraethylammonium (TEA), 4-aminopyridine (4-AP), and glibenclamide had no effect on PA-induced relaxation. Endothelium-deprived corpus cavernosal contractions induced by cumulative addition of Ca2+ to high KCl solution without CaCl2 were significantly inhibited by PA. Also, PA improved relaxant capacity of sildenafil in rat corpus cavernosum. In addition, the perfusion with PA significantly increased the levels of cGMP and expression of mRNA and protein of neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS). Furthermore, intracavernous injection of PA enhanced the rise in intracavernous pressure in rats during cavernosal nerve electric stimulation. In conclusion, PA relaxed the rat corpus cavernosum attributed to both endothelium-dependent and -independent properties. While the former component was mostly involved in nitric oxide signaling pathway, the endothelium-independent mechanism involved in PA-induced relaxation was probably linked to calcium antagonism.

System reliability analysis with small failure probability is investigated in this paper. Because multiple failure modes exist, the system performance function has multiple failure regions and multiple most probable points (MPPs). This paper reports an innovative method combining active learning Kriging (ALK) model with multimodal adaptive important sampling (MAIS). In each iteration of the proposed method, MPPs on a so-called surrogate limit state surface (LSS) of the system are explored, important samples are generated, optimal training points are chosen, the Kriging models are updated, and the surrogate LSS is refined. After several iterations, the surrogate LSS will converge to the true LSS. A recently proposed evolutionary multimodal optimization algorithm is adapted to obtain all the potential MPPs on the surrogate LSS, and a filtering technique is introduced to exclude improper solutions. In this way, the unbiasedness of our method is guaranteed. To avoid approximating the unimportant components, the training points are only chosen from the important samples located in the truncated candidate region (TCR). The proposed method is termed as ALK-MAIS-TCR. The accuracy and efficiency of ALK-MAIS-TCR are demonstrated by four complicated case studies.

Syngas is a promising alternative fuel. The combustion of lean H2/CO meets the demand of high efficiency with low emission. In this paper, the propagation dynamics of lean H2/CO/air premixed flame in a closed duct were experimentally investigated at an atmospheric condition. Propagation of the premixed flame is recorded by using high-speed cinematograph, and results show that the tulip flame is attained in all cases while the occurrence of tulip distortion is determined by both equivalence ratios and hydrogen volume fractions. The flame tip location and speed are attained through using image processing technique. Results show that the analytical theory, which is firstly proposed to model the flame acceleration in tulip flame propagation phase, can be used to predict the early phase flame tip motion in some limited cases. In fuel-lean combustion, with the effect of the diffusive-thermal instability, the analytical theory underestimates the flame tip motion, but overestimates the time instant of the flame initial touching the lateral walls. The overpressure build-up is specially scrutinized in conjunction with the scaled flame tip speed. The disorderly scaled flame tip speed of distorted tulip flame indicates that the distorted tulip flame is a phenomenon which relates to pressure waves. The pressure wave is of importance for tulip distortion, but it cannot change the overpressure build-up directly. Finally, both the flame-wall interaction and the combustion instability have a crucial effect on flame propagation dynamics, and these factors should be accounted for the build of flame propagation models.

Accelerating angiogenesis of diabetic wounds is crucial to promoting wound healing. Currently, vascular endothelial growth factor (VEGF), an angiogenesis-related bioactive molecule, is widely used in clinic to enhance wound angiogenesis, but it faces problems of inactivation and low utilization due to harsh microenvironment. Here, we developed a novel reactive oxygen species (ROS)-scavenging hydrogel aimed to polarize macrophages toward an anti-inflammatory phenotype, inducing efficient angiogenesis in diabetic wounds. This composite hydrogel with good biosafety and mechanical properties showed sustainable release of bioactive VEGF. Importantly, it could significantly reduce ROS level and rapidly improve wound microenvironment, which ensured the activity of VEGF in vitro and in vivo and successful healing eventually. At the same time, the composite hydrogel exhibited excellent antibacterial properties. In vivo results confirmed good anti-inflammatory, stimulated vascularization and accelerated wound healing attributed to the novel ROS-scavenging hydrogel, which might serve as a promising wound dressing in diabetic wound healing.

The rapid selection of salinity-tolerant crops to increase food production in salinized lands is important for sustainable agriculture. Recently, high-throughput plant phenotyping technologies have been adopted that use plant morphological and physiological measurements in a non-destructive manner to accelerate plant breeding processes. Here, a hyperspectral imaging (HSI) technique was implemented to monitor the plant phenotypes of 13 okra (Abelmoschus esculentus L.) genotypes after 2 and 7 days of salt treatment. Physiological and biochemical traits, such as fresh weight, SPAD, elemental contents and photosynthesis-related parameters, which require laborious, time-consuming measurements, were also investigated. Traditional laboratory-based methods indicated the diverse performance levels of different okra genotypes in response to salinity stress. We introduced improved plant and leaf segmentation approaches to RGB images extracted from HSI imaging based on deep learning. The state-of-the-art performance of the deep-learning approach for segmentation resulted in an intersection over union score of 0.94 for plant segmentation and a symmetric best dice score of 85.4 for leaf segmentation. Moreover, deleterious effects of salinity affected the physiological and biochemical processes of okra, which resulted in substantial changes in the spectral information. Four sample predictions were constructed based on the spectral data, with correlation coefficients of 0.835, 0.704, 0.609 and 0.588 for SPAD, sodium concentration, photosynthetic rate and transpiration rate, respectively. The results confirmed the usefulness of high-throughput phenotyping for studying plant salinity stress using a combination of HSI and deep-learning approaches.

The host–guest type molecular size matching strategy, which embodied intramolecular hydrogen bond, aromatic nucleophilic substitution and nucleophilic addition, was utilized to develop a fluorescent probe for GSH specific detection and in situ imaging in organisms.