Search

Abstract Droplet manipulation technologies with surface acoustic waves attract significant attention for applications in fluid handling and bioanalysis. However, existing technologies face challenges in automation, precision, and functional integration, limiting broader applications. In this work, a highly integrated droplet‐sensing acoustofluidic tweezer is developed, incorporating orthogonally arranged slanted finger interdigital transducers and a custom‐designed control and detection circuit system. Using a single acoustic device, this tweezer enables switchable acoustic droplet manipulation and detection, providing multifunctional closed‐loop manipulation of on‐chip microliter‐scale droplets. The platform takes advantage of the wideband frequency response characteristics of the transducers, along with an automated droplet detection algorithm, enabling high‐precision detection of central positions, edge positions, contact diameters, and the number of droplets. With this feedback, automated closed‐loop control of various droplet manipulation functions, including transportation, merging, mixing, splitting, and internal particle enrichment, is achieved for the first time on a single acoustic platform. This significantly enhances the precision, efficiency, and fault tolerance of the manipulation process. This droplet‐sensing acoustofluidic tweezer provides an innovative acoustic solution for droplet manipulation technologies in fields such as fluid processing and biosensing, demonstrating significant application potential.

A substantial body of systematic literature reviews has focused on the topic of industrial decarbonization. However, the decarbonization of industrial heating systems has been hampered by the continued reliance on fossil fuels for industrial heating. Remarkably, at the temperature level of industrial processes, the provision of relatively low-carbon heating is a viable proposition. However, there is a paucity of literature reviews that provide a summary of the carbon neutral heating strategies available for industrial process heat at different temperature levels. To determine the feasibility of providing clean heat at low to high temperature levels, a two-stage systematic literature review of existing research on photovoltaic (PV) and waste-based heating systems was conducted. Notwithstanding the decarbonization potential of PV for clean heating, the temperature of the heat supplied by PV heating systems of all types remains below 100 celsius degree because the efficiency of PV for heating does not offer a significant advantage in relatively high-temperature industrial processes. Conversely, waste incineration-based heating, as a low-carbon fuel, offers the opportunity for high-temperature heat decarbonization in non-energy-intensive industries. Waste incineration-based case studies indicate that the efficiency of waste energy recovery through combined heat and power is more effective than waste incineration power generation. However, studies that provide a well-defined approach to achieving optimal energy efficiency are scarce, despite the notable impact of the distribution ratio of waste incineration steam on the energy recovery efficiency of combined heat and power plants. In addition, most studies have not directly supported the integration of carbon capture and waste incineration to achieve carbon neutrality in heating systems. Finally, after a comprehensive literature review, it can be concluded that the lack of case studies on PV-based industrial heating is at odds with current policies to promote the use of renewable energy sources. Furthermore, there is a noticeable lack of comprehensive research on waste-to-heat cases. To facilitate the advancement of carbon neutrality in the industrial heating sector, this study presents a framework for clean heating that is temperature dependent.

This paper presents a control method for the coordinated motion of a mobile self-reconfigurable robotic system. By utilizing a virtual rigid framework, the system ensures that its configuration remains stable and intact, while enabling modular units to collaboratively track the required trajectory and velocity for mobile tasks. The proposed method generates a virtual rigid structure with a specific configuration and introduces an optimized controller with dynamic look-ahead distance and adaptive steering angle. This controller calculates the necessary control parameters for the virtual rigid structure to follow the desired trajectory and speed, providing a unified reference framework for the coordinated movement of the module units. A coordination controller, based on kinematics and adaptive sliding mode control, is developed to enable each module to track the motion of the virtual rigid structure, ensuring the entire robotic system follows the target path while maintaining an accurate configuration. Extensive simulations and experiments under various configurations, robot numbers, and environmental conditions demonstrate the effectiveness and robustness of the proposed method. This approach shows strong potential for applications in smart factories, particularly in material transport and assembly line supply.

NaNbO3(NN)-based lead-free materials are attracting widespread attention due to their environment-friendly and complex phase transitions, which can satisfy the miniaturization and integration for future electronic components. However, NN materials usually have large remanent polarization and obvious hysteresis, which are not conducive to energy storage. In this work, we investigated the effect of introducing CaTiO3((1−x)NaNbO3-xCaTiO3) on the physical properties of NN. The results indicated that as x increased, the surface topography, oxygen vacancy and dielectric loss of the thin films were significantly improved when optimal value was achieved at x = 0.1. Moreover, the 0.9NN-0.1CT thin film shows reversible polarization domain structures and well-established piezoresponse hysteresis loops. These results indicate that our thin films have potential application in future advanced pulsed power electronics.

The dual-transducer support structure discussed has the advantages of a simple structure and low cost, as well as allowing for the use of both Traveling-Wave (TW) and Standing-Wave (SW) acoustic transportation, supporting its use in pharmaceutical and biochemical analysis, for example. By adjusting the distance between the vibrating plate and the reflector which forms SW field in the y direction, the control of the position of the SW nodes or the TW component along the x direction allows the formation of a Two-Dimensional Standing Wave (2D-SW) or a Traveling Wave (TW) acoustic field, and these could be used for transportation in the x direction. It has been found that the x position of the SW nodes can be adjusted through changing the temporal phase shift, θ, which permits multiple objects to be transported using the 2D-SW mode. By comparison, TWs in the opposite direction could be generated at a pair of specific temporal phase shifts, allowing fast transportation using the TW mode. In this research work, an experiment has been carried out to transport polystyrene spheres using the two modes by programming the temporal phase shift, θ, this illustrating that precise position control of the multiple objects transported was possible using the 2D-SW mode, while high-speed transportation (up to 540 mm/s) was realized using the TW mode, showing that the dual-transducer support structure could be used effectively for accurate and fast transportation. As a fully non-contact method, the dual-transducer support structure can be seen to work in the 2D-SW mode for reaction synthesis or detection applications, and also in TW mode for rapid sample transportation applications.

Abstract To investigate the prevalence and indoor environmental influencing factors of wheeze and asthma among preschool children in Urumqi, Xinjiang, China to provide a strong basis for prevention and control. In August 2019, a cross-sectional study involving 8153 preschool children was conducted in 60 kindergartens in Urumqi. The ALLHOME-2 questionnaire was used for childhood wheeze and asthma survey, and the dampness in buildings and health (DBH) questionnaire was used for the childhood home dwelling and living environment survey. Multivariate unconditional logistic regression was then used to analyze the potential influencing factors of childhood asthma and wheeze. The prevalence of wheeze and asthma in children was 4.7% and 2.0%, respectively. Multivariate unconditional logistic regression results suggested that ethnicity other than the Han Chinese (odds ratio (OR) 1.39, 95% confidence interval (CI) 1.05–1.84), caesarean section (OR 1.24, 95% CI 1.00–1.53), family history of asthma (OR 5.00, 95% CI 3.36–7.44), carpet or floor bedding at home (OR 1.40, 95% CI 1.05–1.87), purchasing new furniture in the mother’s residence during pregnancy (OR 1.58, 95% CI 1.06–2.36), pet keeping in the residence at aged 0–1 year (OR 1.55, 95% CI 1.13–2.13), passive smoking by child in the current residence (OR 1.35, 95% CI 1.01–1.80), and having mould or hygroma in the child's residence at aged 0–1 year (OR 1.72, 95% CI 1.12–2.64) were risk factors for wheeze. In addition, Girls (OR 0.73, 95% CI 0.59–0.90) was a protective factor for wheeze. Caesarean section (OR 1.46, 95% CI 1.06–2.00), family history of asthma (OR 7.06, 95% CI 4.33–11.53), carpet or floor bedding at home (OR 2.20, 95% CI 1.50–3.23), and pet keeping in the residence at aged 0–1 year (OR 1.64, 95% CI 1.04–1.83) were risk factors for asthma, whereas Girls (OR 0.58, 95% CI 0.42–0.80) was a protective factor for asthma. This survey indicates that the purchase of new furniture, the placement of carpet or floor bedding in the child's residence, the pets keeping, room dampness or moldy phenomena, and passive smoking may all contribute to an elevated risk of wheeze or asthma in children.

Acoustic manipulation techniques have gained significant attention across various fields, particularly in medical diagnosis and biochemical research, due to their biocompatibility and non-contact operation. In this article, we review the broad range of biomedical applications of micro/nano-motors that use acoustic manipulation methods, with a specific focus on cell manipulation, targeted drug release for cancer treatment and genetic disease diagnosis. These applications are facilitated by acoustic-propelled micro/nano-motors and nanoparticles which are manipulated by acoustic tweezers. Acoustic systems enable high precision positioning and can be effectively combined with magnetic manipulation techniques. Furthermore, acoustic propulsion facilitates faster transportation speeds, making it suitable for tasks in blood flow, allowing for precise positioning and in-body manipulation of cells, microprobes, and drugs. By summarizing and understanding these acoustic manipulation methods, this review aims to provide a summary and discussion of the acoustic manipulation methods for biomedical research, diagnostic, and therapeutic applications.

Summary: Characterizing material flows and environmental impacts of plastic value chain is crucial for sustainable plastic management. Here, we combine material flow analysis and life cycle assessment methods to map the flows of eight major plastics and investigate the multiple environmental impacts of China’s plastic value chain. We find that packaging and textile sectors dominate plastic consumption and are responsible for the value chain environmental burdens, but with low recycling rates. Major environmental impacts are generated in plastic production and product manufacturing stages because of the consumption of coal-based feedstocks and electricity. We therefore set up six scenarios by considering carbon neutrality energy pathway, plastic recycling improvement, and technology updating, finding that the value chain environmental impact can be reduced by 14%–57% in 2060 under combined scenario. Particularly, carbon neutrality renewable energy pathway plays an important role. These findings provide valuable insights to identify key mitigation pathways for plastic value chain.

ABSTRACT The Enterococcus faecalis acyl-acyl carrier protein (ACP) phosphate acyltransferase PlsX plays an important role in phospholipid synthesis and exogenous fatty acid incorporation. Loss of plsX almost completely blocks growth by decreasing de novo phospholipid synthesis, which leads to abnormally long-chain acyl chains in the cell membrane phospholipids. The ∆plsX strain failed to grow without supplementation with an appropriate exogenous fatty acid. Introduction of a ∆fabT mutation into the ∆plsX strain to increase fatty acid synthesis allowed very weak growth. The ∆plsX strain accumulated suppressor mutants. One of these encoded a truncated β-ketoacyl-ACP synthase II (FabO) which restored normal growth and restored de novo phospholipid acyl chain synthesis by increasing saturated acyl-ACP synthesis. Saturated acyl-ACPs are cleaved by a thioesterase to provide free fatty acids for conversion to acyl-phosphates by the FakAB system. The acyl-phosphates are incorporated into position sn1 of the phospholipids by PlsY. We report the tesE gene encodes a thioesterase that can provide free fatty acids. However, we were unable to delete the chromosomal tesE gene to confirm that it is the responsible enzyme. TesE readily cleaves unsaturated acyl-ACPs, whereas saturated acyl-ACPs are cleaved much more slowly. Overexpression of an E. faecalis enoyl-ACP reductase either FabK or FabI which results in high levels of saturated fatty acid synthesis also restored the growth of the ∆plsX strain. The ∆plsX strain grew faster in the presence of palmitic acid than in the presence of oleic acid with improvement in phospholipid acyl chain synthesis. Positional analysis of the acyl chain distribution in the phospholipids showed that saturated acyl chains dominate the sn1-position indicating a preference for saturated fatty acids at this position. High-level production of saturated acyl-ACPs is required to offset the marked preference of the TesE thioesterase for unsaturated acyl-ACPs and allow the initiation of phospholipid synthesis.

The Pseudomonas putida F1 genome and those of many other pseudomonads contain two tandem genes encoding acyl-CoA ligases Pput_1340 (fadD1) and Pput_1339 (fadD2) with Pput_1339 (fadD2) being the upstream gene. The fadD designation was assigned when both genes were found to complement the growth of an Escherichia coli acyl-CoA synthetase fadD deletion strain with oleic acid as sole carbon source. Site-directed mutagenesis showed that residues of the ATP/AMP domain required for function of E. coli FadD were also essential for full function of FadD1 and FadD2. Growth of the constructed ∆fadD1, ∆fadD2, and ∆fadD1∆fadD2 strains was tested in minimal medium with different chain length fatty acids as sole carbon sources. Lack of FadD1 significantly retarded growth with different chain length fatty acids and lack of both FadD1 and FadD2 further retarded growth. Derivatives of the ∆fabA∆desA unsaturated fatty acid auxotrophic strain carrying a deletion of either ∆fadD1 or ∆fadD2 were constructed. Growth of the ∆fabA∆desA∆fadD1 strain was very weak, whereas the ∆fabA∆desA∆fadD2 strain grew as well as the ∆fabA∆desA parent strain. Overexpression of either fadD1 or fadD2 restored growth of the ∆fabA∆desA∆fadD1 strain with fadD2 overexpression having a greater effect than fadD1 overexpression. The ∆fadD1 or ∆fadD2 genes are cotranscribed although the expression level of fadD1 is much higher than that of fadD2. This is attributed to a fadD1 promoter located within the upstream FadD2 coding sequence. IMPORTANCE Pseudomonas bacteria demonstrate a great deal of metabolic diversity and consequently colonize a wide range of ecological niches. A characteristic of these bacteria is a pair of genes in tandem annotated as acyl-CoA ligases involved in fatty acid degradation. The Pseudomonas putida F1 genome is annotated as having at least nine genes encoding acyl-CoA ligases which are scattered around the chromosome excepting the tandem pair. Since similar tandem pairs are found in other pseudomonads, we have constructed and characterized deletion mutants of the tandem ligases. We report that the encoded proteins are authentic acyl-CoA ligases involved in fatty acid degradation. [ABSTRACT FROM AUTHOR]

The self-reconfigurable modular robotic system is a class of robots that can alter its configuration by rearranging the connectivity of their component modular units. The reconfiguration deformation planning problem is to find a sequence of reconfiguration actions to transform one reconfiguration into another. In this paper, a hybrid reconfiguration deformation planning algorithm for modular robots is presented to enable reconfiguration between initial and goal configurations. A hybrid algorithm is developed to decompose the configuration into subconfigurations with maximum commonality and implement distributed dynamic mapping of free vertices. The module mapping relationship between the initial and target configurations is then utilized to generate reconfiguration actions. Simulation and experiment results verify the effectiveness of the proposed algorithm.

Abstract Background Eczema is a chronic inflammatory disease associated with impaired quality of life. We identified indoor environmental risk factors, to provide strong evidence for the prevention and control of eczema in preschool children. Methods Using a cross-sectional study with stratified random cluster sampling, we conducted a self-administered questionnaire survey among 8153 parents of children aged 2–8 years in 60 kindergartens in six districts of Urumqi city during August 2019. Results Among 8153 preschool children, 12.0% of the children have been diagnosed with eczema. Multivariate logistic regression analysis showed that caesarean section (odds ratio [OR] = 1.18, 95% confidence interval [CI]: 1.03–1.36), being an only child (OR = 1.36, 95% CI: 1.18–1.57), presence of mould or moisture in the mother’s home before pregnancy (OR = 1.53, 95% CI: 1.17–2.00), presence of flies or mosquitoes in the dwelling currently (OR = 1.31, 95% CI: 1.10–1.55), pets kept in the child’s home currently (OR = 1.23, 95% CI: 1.01–1.51), presence of pets during child’s first year (OR = 1.45, 95% CI: 1.14–1.85), and family history of eczema (OR = 3.53, 95% CI: 2.98–4.19) are the risk factors for the development of eczema, whereas ethnicity other than the Han Chinese (OR = 0.77, 95% CI: 0.61–0.96) is a protective factor for eczema. Conclusion Preschool children in Urumqi are at a high risk of eczema, particularly those of the Han Chinese ethnicity. Parents should be attentive to the indoor living environment of children and take actions to reduce indoor humidity, pest control and elimination, and avoid raising pets to reduce the risk of development of eczema in children.

The phospholipid acyl chains of Enterococcus faecalis can be derived either by de novo synthesis or by incorporation of exogenous fatty acids through the fatty acid kinase complex (Fak)-phosphate acyltransferase (PlsX) pathway. Exogenous fatty acids suppress fatty acid synthesis through the transcriptional repressor FabT, the loss of which eliminated regulation of de novo fatty acid biosynthesis and resulted in decreased incorporation of exogenous unsaturated fatty acids. Purified FabT bound to the promoters of several fatty acid synthesis genes that contain a specific palindromic sequence and binding was enhanced by acylated derivatives of acyl carrier protein B (acyl-AcpB). The loss of the PlsX pathway blocked FabT-dependent transcriptional repression in the presence of oleic acid. Transcriptional repression was partially retained in a E. faecalis ΔacpB strain which showed decreased fatty acid biosynthesis in the presence of exogenous unsaturated fatty acids. The FabT-dependent activity remaining in the ΔacpB strain indicates that acylated derivatives of AcpA were weak enhancers of FabT binding although AcpA is believed to primarily function in de novo fatty acid synthesis.

Drawing on social information processing theory, the present study examines how and when leader coaching can be beneficial for team performance. Based on a sample of 58 teams from a sanitary product company in China, we found that peer coaching served as a mediator linking leader coaching and team performance. Moreover, the team individualistic/collectivism value moderated the first-stage relationship that the relationship between leader coaching and peer coaching was more positive when the team individualism value was low, but not significant when the team individualism value was high; while team task interdependence moderated the second-stage relationship that the relationship between peer coaching and team performance was more positive when the team task interdependence was high, but not significant when it was low. The findings enrich our understandings of the effectiveness of leader coaching behavior by uncovering the theoretical mechanism and boundary conditions. The study also provides important implications for coaching practice in organizations.

Sustainable crop production is a significant challenge in China. To achieve this goal, it is necessary to evaluate environmental impacts related to the sustainable development of crop production by integrating scientific and practical indicators. Therefore, this study employed emergy and index decomposition analysis approaches to assess the environmental impacts of non-point source pollution and the overall performance of crop production in China’s 31 provinces. First, the emergy flow of emission impacts and two new indicators, the emergy sustainability index and the emergy-based pollutant-producing coefficient, were proposed to comprehensively measure crop production performance from 2012 to 2015. The results demonstrated that the environmental impacts of non-point source pollution (EIN) were predominantly attributed to total nitrogen and phosphorus contents and mulching film residuals, which substantially increased the total emergy used and reduced the sustainability of crop production in each province. The ratio of EIN plus purchased resources (F) to total emergy used (U) were consistently greater than 80% in all 31 provinces, while the ratio of local resources including the emergy of local renewable (R) and non-renewable resources (N) to the total emergy was relatively small, accounting for less than 20% in all provinces. Then, a logarithmic mean Divisia index decomposition method was applied to identify the key driving forces influencing the evolution of EIN. The decomposition analysis indicated that the economy factor had a major promoting effect on EIN growth in all provinces except Beijing and Shanghai. Intensity and technology factors had a limiting effect on EIN growth. These findings provide valuable insights for developing appropriate crop production policies that consider local conditions.

ABSTRACT The precursors of the diffusible signal factor (DSF) family signals of Xanthomonas campestris pv. campestris are 3-hydroxyacyl-acyl carrier protein (3-hydroxyacyl-ACP) thioesters having acyl chains of 12 to 13 carbon atoms produced by the fatty acid biosynthetic pathway. We report a novel 3-oxoacyl-ACP reductase encoded by the X. campestris pv. campestris XCC0416 gene (fabG2), which is unable to participate in the initial steps of fatty acyl synthesis. This was shown by the failure of FabG2 expression to allow growth at the nonpermissive temperature of an Escherichia coli fabG temperature-sensitive strain. However, when transformed into the E. coli strain together with a plasmid bearing the Vibrio harveyi acyl-ACP synthetase gene (aasS), growth proceeded, but only when the medium contained octanoic acid. In vitro assays showed that FabG2 catalyzes the reduction of long-chain (≥C8) 3-oxoacyl-ACPs to 3-hydroxyacyl-ACPs but is only weakly active with shorter-chain (C4, C6) substrates. FabG1, the housekeeping 3-oxoacyl-ACP reductase encoded within the fatty acid synthesis gene cluster, could be deleted in a strain that overexpressed fabG2 but only in octanoic acid-supplemented media. Growth of the X. campestris pv. campestris ΔfabG1 strain overexpressing fabG2 required fabH for growth with octanoic acid, indicating that octanoyl coenzyme A is elongated by X. campestris pv. campestris fabH. Deletion of fabG2 reduced DSF family signal production, whereas overproduction of either FabG1 or FabG2 in the ΔfabG2 strain restored DSF family signal levels. IMPORTANCE Quorum sensing mediated by DSF signaling molecules regulates pathogenesis in several different phytopathogenic bacteria, including Xanthomonas campestris pv. campestris. DSF signaling also plays a key role in infection by the human pathogen Burkholderia cepacia. The acyl chains of the DSF molecules are diverted and remodeled from a key intermediate of the fatty acid synthesis pathway. We report a Xanthomonas campestris pv. campestris fatty acid synthesis enzyme, FabG2, of novel specificity that seems tailored to provide DSF signaling molecule precursors.

Recent strides in micro- and nanomanufacturing technologies have sparked the development of micro-/nanorobots with enhanced power and functionality. Due to the advantages of on-demand motion control, long lifetime, and great biocompatibility, magnetic propelled micro-/nanorobots have exhibited considerable promise in the fields of drug delivery, biosensing, bioimaging, and environmental remediation. The magnetic fields which provide energy for propulsion can be categorized into rotating and oscillating magnetic fields. In this review, recent developments in oscillating magnetic propelled micro-/nanorobot fabrication techniques (such as electrodeposition, self-assembly, electron beam evaporation, and three-dimensional (3D) direct laser writing) are summarized. The motion mechanism of oscillating magnetic propelled micro-/nanorobots are also discussed, including wagging propulsion, surface walker propulsion, and scallop propulsion. With continuous innovation, micro-/nanorobots can become a promising candidate for future applications in the biomedical field. As a step toward designing and building such micro-/nanorobots, several types of common fabrication techniques are briefly introduced. Then, we focus on three propulsion mechanisms of micro-/nanorobots in oscillation magnetic fields: (1) wagging propulsion; (2) surface walker; and (3) scallop propulsion. Finally, a summary table is provided to compare the abilities of different micro-/nanorobots driven by oscillating magnetic fields.