Grain supply chain transportation problem is a nontrivial and intractable issue for many developing countries. Grain as a bulk commodity is usually transported by bulk carriers. By taking into ...account the special condition of Ukraine, we proposed the containerized grain supply chain transportation optimization problem. In this problem, the sustainable supply chain system delivers grains in containers among primary elevators, intermodal yards, and port container terminals. Then, a containerized grain transportation model was developed to minimize the total cost of the sustainable supply chain system. Specifically, 20-foot containers were proven as more reasonable to be used in this paper. We also considered different transportation tools: trucks that can load one 20-foot container, trailers that can load two 20-foot containers, and wagons that can hold two 20-foot containers. Additionally, a disruption model was proposed by considering different disruption scenarios. Based on an analysis of the simulation results, some cost minimization strategies were proposed. Finally, a sensitivity analysis that aimed to analyze the effect of the proposed strategies on the minimal total cost and sustainability of the supply chain was conducted. The main conclusions drawn from the simulation are that the established food supply chain model is meaningful and accurate, and the incorporation of the disruption model aligns with practical requirements. Additionally, an increase in intermodal yard capacity, truck park size, and wagon park size decreases the total cost of the supply chain. The first two have a positive effect on the sustainability of the supply chain, while the latter increases the disruption risk of the supply chain.
Under population pressure, the transition from the long-fallow shifting cultivation to short-fallow shifting cultivation with associated land degradation has been claimed to be unavoidable and ...sedentary cultivation would be advocated as the only future to replace the unsustainable short-fallow shifting cultivation in the mainstream research and development. The recent development of the shifting cultivation system in Yunnan, Southwest China demonstrates how local peoples hybridize elements of the traditional shifting cultivation and the new agriculture and forestry technologies as a new and dynamic rotational agroforestry system for economic development without losing the natural resource base. Comparing experiences in other regions and under some conditions, the rotational agroforestry system may be promoted as a viable option for development of the shifting cultivation system in the mountainous areas where the introduction of sedentary agriculture is much constrained.
The biosynthesis of histidine, a proteinogenic amino acid, has been extensively studied due to its importance in bacterial growth and survival. Histidinol-phosphate phosphatase (Hol-Pase), which is ...responsible for the penultimate step of histidine biosynthesis, is generally the last enzyme to be characterized in many bacteria because its origin and evolution are more complex compared to other enzymes in histidine biosynthesis. However, none of the enzymes in histidine biosynthesis, including Hol-Pase, have been characterized in
, which is an important opportunistic Gram-negative pathogen that can cause serious human infections. In our previous work, a transposon mutant of
was found to display a growth defect on glucose-containing minimal solid medium. In this study, we found that the growth defect was due to incomplete histidine auxotrophy caused by PA0335 inactivation. Subsequently, PA0335 was shown to encode Hol-Pase, and its function and enzymatic activity were investigated using genetic and biochemical methods. In addition to PA0335, the roles of 12 other predicted genes involved in histidine biosynthesis in
were examined. Among them,
(PA3165),
(PA3152), and
(PA3151) were found to be dispensable for histidine synthesis, whereas
(PA4449),
(PA5067),
(PA5140),
(PA5143),
(PA5066),
(PA4447), and
(PA5141) were essential because deletion of each resulted in complete histidine auxotrophy; similar to the case for PA0335,
(PA5142) or
(PA4448) deletion caused incomplete histidine auxotrophy. Taken together, our results outline the histidine synthesis pathway of
Histidine is a common amino acid in proteins. Because it plays critical roles in bacterial metabolism, its biosynthetic pathway in many bacteria has been elucidated. However, the pathway remains unclear in
, an important opportunistic pathogen in clinical settings; in particular, there is scant knowledge about histidinol-phosphate phosphatase (Hol-Pase), which has a complex origin and evolution. In this study,
Hol-Pase was identified and characterized. Furthermore, the roles of all other predicted genes involved in histidine biosynthesis were examined. Our results illustrate the histidine synthesis pathway of
The knowledge obtained from this study may help in developing strategies to control
-related infections. In addition, some enzymes of the histidine synthesis pathway from
might be used as elements of histidine synthetic biology in other industrial microorganisms.
An analysis of physics-based optical flow Wang, Bo; Cai, Zemin; Shen, Lixin ...
Journal of computational and applied mathematics,
03/2015, Volume:
276
Journal Article
Peer reviewed
Open access
A variational solution of the physics-based optical flow equation is studied for extraction of high-resolution velocity fields from flow visualization images. The solution to preserve discontinuities ...in a fluid velocity field is mathematically justified. The uniqueness of the solution and the convergence of a successive approximation sequence are proven. A numerical algorithm is developed and examined through numerical experiments.
Functional hydrogels have attracted tremendous interest in biomedical fields. In this study, we prepare hydrogel based on 2-(methacryloyloxy)ethyldimethyl-(3-sulfopropyl) (SBMA) and 2-hydroxyethyl ...methacrylate (HEMA), and GelMA acts as crosslinking agent to crosslink the P(SBMA-co-HEMA) molecular chain. The hydrogel exhibits excellent mechanical properties (strength up to 1.21 MPa), fatigue resistance (withstands 50 compression tensile cycles and remains stable), and high transmittance enables visualization of hydrogel dressings. Furthermore, antibacterial experiments proves that hydrogel could significantly resist the adhesion of
E. coli.
and the hydrogel also has excellent antifreezing and water retention properties. More importantly, in vitro and in vivo assays reveals the hydrogel has excellent biocompatibility and stability, making them competitive candidates for biomedical applications such as wound dressing.
Airport Economic Zone (AEZ) is a suburban area whose infrastructure, land-use, and economy are centered on an airport. More than 100 AEZs are under planning and development in China. Industry choice ...is the critical issue for all the AEZs. To ensure that all the industries located in AEZs are closely related to airports and air transport, first, we create a pool of optional industries for AEZs based on the industrial input-output model. Second, we construct a multi-objective combinatorial optimization model subject to the constraints of land area of an AEZ, targeting the maximum number of employees, the largest GDP, the highest degree of aviation correlation, the fullest utilization of basic resources, and the greatest policy support. Third, to verify the feasibility of this model in practice, we choose the Zhengzhou Airport Economic Comprehensive Experimental Zone for case study. We divide these five objectives into two categories: economic objectives and non-economic objectives, and put different weights on them to describe different political preferences, and then discuss the calculation results in three scenarios. Finally, we come to the conclusion that comprehensive consideration of every characteristic of each industry can reasonably determine the scale of industrial land use and increase industrial economic benefit in AEZs. Our research provides a new quantitative and reliable method for industry choice and land use planning of an AEZ.
•Propose a quantitative standard to screen the aviation-related industries suitable for an Airport Economic Zone.•Transform the industry choice model into a multi-objective unbounded knapsack problem.•Case study on Zhengzhou Airport Economic Zone has verified the feasibility of this industry choice model in practice.•This method can reasonably determine the scale of industrial land use and increase industrial economic benefit in AEZs.
Summary
Pseudomonas aeruginosa causes serious acute and chronic infections in humans. Major differences exist in disease pathogenesis, clinical treatment and outcomes between acute and chronic ...infections. P. aeruginosa acute infection characteristically involves the type III secretion systems (T3SS) while chronic infection is often associated with the formation of biofilms, a major cause of difficulties to eradicate chronic infections. The choice between acute and chronic infection or the switch between them by P. aeruginosa is controlled by regulatory pathways that control major virulence factors and genes associated with biofilm formation. In this study, we characterized a hybrid sensor kinase PA1611 that controls the expression of genes associated with acute and chronic infections in P. aeruginosa PAO1. Expression of PA1611 completely repressed T3SS and swarming motility while it promoted biofilm formation. The protein PA1611 regulates two small RNAs (sRNAs), rsmY and rsmZ which in turn control RsmA. Independent of phosphate relay, PA1611 interacts directly with RetS in vivo. The positive effect of RetS on factors associated with acute infection could presumably be restrained by PA1611 when chronic infection conditions are present. This RetS–PA1611 interaction, together with the known RetS–GacS interaction, may control disease progression and the lifestyle choice of P. aeruginosa.
High-resolution images are often desired but made impossible because of hardware limitations. For the high-resolution model proposed by Bose and Boo (see Int. J. Imaging Syst. Technol., vol.9, ...p.294-304, 1998), the iterative wavelet-based algorithm has been shown to perform better than the traditional least square method when the resolution ratio M is two and four. In this paper, we discuss the minimally supported biorthogonal wavelet system that comes from the mathematical model by Bose and Boo and propose a wavelet-based algorithm for arbitrary resolution ratio M/spl ges/2. The numerical results indicate that the algorithm based on our biorthogonal wavelet system performs better in high-resolution image reconstruction than the wavelet-based algorithm in the literature, as well as the common-used least square method.
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