To detect the quality of medicinal human albumin by capillary electrophoresis, we produced a fused‐silica capillary coated with thermally cross‐linked poly(vinyl pyrrolidone) to prohibit protein ...adsorption. This type of capillary was easily obtained by injecting an aqueous poly(vinyl pyrrolidone) solution into a fused‐silica capillary and thermally annealing it at 200°C. Notably, stable and low electro‐osmotic flow was obtained in the poly(vinyl pyrrolidone)‐coated capillary at pH 2.20–9.00, and the separation of a mixture of four basic proteins indicated that the poly(vinyl pyrrolidone)‐coated capillary exhibits excellent repeatability and separation efficiency; moreover, the separation of these four basic proteins could even be achieved at pH 7.00. The protein recovery percentage of human serum albumin in a single‐protein solution and a mixed blood proteins solution was determined to be 97.03 and 95.40% in the poly(vinyl pyrrolidone)₅₀–₃ (representing the concentration of the capillary‐injected poly(vinyl pyrrolidone) aqueous solution, 50 mg/mL, and thermal annealing time, 3 h) capillary, respectively. Based on these results, we used the poly(vinyl pyrrolidone)₅₀–₃‐coated capillary to quantify the protein content of human albumin, and the results obtained from run to run, day to day and capillary to capillary demonstrated that the coated capillary could be used for quality testing commercially available human albumin.
•A dataset on small target pests on greenhouse sticky traps.•A novel solution was developed for counting multiple small targets based on density maps, simultaneously.•An adaptive sample equalization ...algorithm was developed to tackle the issue of class imbalance.
Whiteflies and fruit flies are common pests that adversely affect greenhouse crops, so it is vital to control their numbers promptly. Current research involves setting up artificial monitoring devices with fixed yellow sticky traps (YSTs), for pest surveillance. However, these devices can only be installed in specific environments and additional interventions may impact the actual distribution of greenhouse pests. On the other hand, detection methods, which are the most commonly used, struggle to accurately detect overlapping or closely interacting small insects, which is a common occurrence in the presence of pests. In this paper, we propose a novel solution for the multi-species pest recognition and counting method based on a density map to tackle pest counting in the greenhouse. To reduce interference between different types of objects, we used two annotation maps to represent the distribution of each object separately. Then, two counting branches are designed to count the pests, respectively. Finally, the detected pests are mapped onto the original image to display their spatial positions. In addition, an adaptive sample equalization method is proposed to address the issue of class imbalance in images, and the atrous spatial pyramid pooling (ASPP) structure and the CBAM attention mechanism are added to the fruit fly branches to focus on learning fruit fly features from crowded edges of YSTs. When applied to split images, our method achieved reliable counting performance in counting both whiteflies and fruit flies, with R2 scores of 0.973 and 0.972, respectively. This method has been embedded into mobile devices to assist greenhouse workers in monitoring pest populations in the field. The experiments show that the proposed method provides a promising direction for counting multiple small target insects and monitoring pest populations in crowded images. At the same time, it demonstrates the potential of density map methods in various small target detection scenarios.
In recent years, the potential of robotic harvesting in greenhouse tomato production has garnered significant attention within the tomato industry. However, there is a lack of sufficient research on ...the complete replacement of manual harvesting with this technology. In this paper, we propose a tomato harvesting method that utilizes a nesting approach to simplify the process and minimize damage. The paper describes the tomato harvesting robot prototype, the visual system equipped with three vision‐based tomato detectors: YOLOv5_CBAM, which incorporates a convolutional block attention module; YOLOv5_SE, enhanced with a squeeze‐and‐excitation block; and a standard YOLOv5s model. Additionally, a novel shear gripping method for fruit bunches is presented, utilizing a bottom‐up snapping technique during harvesting. Point cloud data are utilized to determine the position of the tomato's main stem and bunch. The paper includes field tests and experimental findings, which indicate that the YOLOv5_CBAM model achieves the highest precision (82.62%) and recall (82.57%), outperforming YOLOv5_SE and standard YOLOv5s. Field experiments demonstrate that the improved end‐effector and vision system have significantly enhanced the robot's performance, achieving a 57.5% harvesting success rate in just 14.9 s.
The real-time simulation of large-scale agricultural operations will offer farmers data-driven and physically consistent decision support, facilitated by predictive digital twins. To construct a ...predictive digital twin, the initial step involves 3D reconstruction of plant geometry. In this paper, a high-resolution, accurate 3D reconstruction of tomato plants, Tomato-NeRF, is proposed, which is specially used for three-dimensional reconstruction of tomato plants. Our approach used a modular design to integrate ideas from their research paper into Tomato-NeRF. By using hash encoding to map coordinates to trainable feature vectors, we balance quality, memory usage, and performance in NeRF training. The proposal sampler targets key regions for rendering, and customized loss functions are designed to optimize specific tasks. The effectiveness of our approach is demonstrated by the ability to generate high-resolution geometric models from phone camera data. Comparative results show that Tomato-NeRF has significant advantages over Instant-NGP and MipNeRF in the tomato plant reconstruction task. The data acquisition method is simpler and more efficient than other reconstruction methods, providing a practical solution for real-time agricultural simulations.
In this study, a set of well-defined multiarm star copolymers, hyperbranched poly(ethylenimine)-graft-poly(ethylene glycol) (bPEI-g-PEG) with different PEG grafting ratios were synthesized. The star ...PEG-based coatings were then prepared by immobilizing the corresponding copolymers onto poly(dopamine) (PDA)-coated substrates. The chemical composition, hydrophilicity, surface topography, and thickness of the coatings were studied by X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), atomic force microscopy (AFM), and variable angle spectroscopic ellipsometry (VASE), respectively. Furthermore, the surface PEG chain density of star PEG-based coating was evaluated quantitatively and compared with that of linear PEG-based coating. Our results showed that the amount of proteins (albumin from bovine serum, fibrinogen, and lysozyme) adsorbed on the star PEG-based coating as measured by surface plasmon resonance (SPR) was found to be dependent on the surface PEG chain density, which was controlled by the polymer incubation concentrations and PEG grafting ratios. Generally, the star-shaped PEG gave the surface with higher PEG chain density than linear ones and the amount of adsorbed proteins decreased with increasing surface PEG chain density. At last, the star PEG-based coating was successfully applied into the capillary inner surface for protein separation by capillary electrophoresis (CE).
In this study, a set of well-defined multiarm star copolymers, hyperbranched poly(ethylenimine)-graft-poly (ethylene glycol) (bPEI-g-PEG) with different PEG grafting ratios were synthesized. The star ...PEG-based coatings were then prepared by immobilizing the corresponding copolymers onto poly(dopamine) (PDA)-coated substrates. The chemical composition, hydrophilicity, surface topography, and thickness of the coatings were studied by X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), atomic force microscopy (AFM), and variable angle spectroscopic ellipsometry (VASE), respectively. Furthermore, the surface PEG chain density of star PEG-based coating was evaluated quantitatively and compared with that of linear PEG-based coating. Our results showed that the amount of proteins (albumin from bovine serum, fibrinogen, and lysozyme) adsorbed on the star PEG-based coating as measured by surface plasmon resonance (SPR) was found to be dependent on the surface PEG chain density, which was controlled by the polymer incubation concentrations and PEG grafting ratios. Generally, the star-shaped PEG gave the surface with higher PEG chain density than linear ones and the amount of adsorbed proteins decreased with increasing surface PEG chain density. At last, the star PEG-based coating was successfully applied into the capillary inner surface for protein separation by capillary electrophoresis (CE).
The gas flow in the intake ports affects the gas flow characteristic in the engine cylinder and affects the performance of the engine indirectly. In this paper, based on the intake ports of a ...gasoline engine, the steady numerical simulation of the gas flow in the intake ports and cylinder is done by AVL Fire. The simulation results give the flow coefficient curve under different valve lifts, which provides theoretical basis for the design of the valve cam. At the same time the stream line, flow speed and interference of gas flow in the intake ports and cylinder under different valve lifts is simulated, which will give the theoretical supports for the design of the intake ports and the valves, and improve the gasoline injecting.
Two‐sided platforms are often coupled with exclusive hardware products that connect two sides of users, the consumers of the hardware product (i.e., buyers) and the application developers (i.e., ...sellers). The hardware product in the platform business model introduces three important issues that are not yet well understood in the literature of platform pricing: potentially downward‐trending production cost, product quality improvements, and consumers’ strategic behaviors. Using analytical modeling, our study explicitly factors in these issues in analyzing a monopoly platform owner’s two‐sided pricing problem. The platform sequentially introduces and prices quality‐improving hardware products, for which the costliness of quality may decrease. Strategic buyers make purchasing and upgrading decisions, which dynamically determine the buyer‐side network size. Meanwhile, the seller‐side network size is determined endogenously. We find that, an increase in the likelihood or magnitude of the future costliness reduction raises the initial buyer‐side price of the low‐quality product and lowers the seller‐side fee. This strategy, in turn, creates an indirect intertemporal effect that allows the platform to also raise the buyer‐side price(s) of the product(s) sold later. These findings contrast with conventional wisdom and provide an economic explanation for premium introductory pricing of many platform products. Moreover, we find that strengthening the network effect can result in more pronounced increases in the buyer‐side prices.
This paper examines the effect of product substitutability on the equilibrium profits in a distribution channel of two symmetric manufacturers selling substitutable products to consumers through a ...nonexclusive retailer. Conventional wisdom suggests that when the products are more substitutable, the retailer will be better off while the manufacturers will be worse off, owing to the dominance of the competition effect of substitutability. In this work, we identify the hitherto neglected demand effect of substitutability and show that the relative strength between the competition and demand effects is the key to this result. As the products become more substitutable, the upstream competition does intensify, but vitally, the demand may expand. We show that the interests of the retailer and manufacturers can be aligned in terms of product substitutability, depending on both the demand and supply factors. Surprisingly, the conventional result can even be completely reversed such that the manufacturers benefit from a certain level of substitutability for some demand patterns. Assuming linear demand, we further isolate the important role of the bargaining power balance and the alternative of agency selling format in moderating the competition effect. For example, as the retailer gains more bargaining power, the (negative) demand effect can overshadow the (positive) competition effect such that a higher degree of substitutability can actually hurt the retailer. Our findings provide valuable implications for persuasive advertising and category management.
This study is motivated by the ubiquitous practical existence of common retailer distribution channels (e.g., a grocery store offering multiple brands of the same product). Demand interdependence ...(product substitutability) among various brands is critical and thus we investigate its impact on firms’ profits. Using an economic framework with manufacturers operating as Stackelberg leaders, our analysis reveals unique and substantive insights dependent on the underlying market demand structure, and in some cases, the extent of supply coverage. For the Spence–Dixit–Vives demand structure, we find that competing manufacturers prefer to offer brands with low levels of substitutability while retailer’s preferences are moderated by the interaction effect between the number of competing brands and level of product substitutability (essentially the retailer prefers high levels of substitutability when the number of brands is “small," and vice versa). For the Shubik–Levitan demand structure, manufacturers may prefer high or low levels of product substitutability depending on the extent of supply coverage while the retailer always prefers high levels of product substitutability. These findings offer useful prescriptions for category management and persuasive advertising.
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