The fourth-order geometrically nonlinear partial differential equations of motion for the Vierendeel Sandwich Plate (VSP), with five generalized displacements, are established considering the ...second-order nonlinear variables in the displacement components of the Green strain tensor. Considering the material orthogonality of the equivalent thin plate with the upper surface layer, upper and lower ribs of VSP, the short column is equivalent to the transverse isotropic interlayer of the material, and the equivalent material parameters of the upper and lower ribs of the plate are derived using mechanical methods. An energy function is established by treating strain as an independent variable, and the geometric nonlinear vibration equation of VSP is obtained through functional variation. Then, the free vibration solution expressed by the elliptic function is obtained using the Galerkin method, and the accuracy of the numerical results of the nonlinear equation is verified by examples. The numerical simulation obtained curves on the relationship between the ratio of the linear period to the nonlinear period and amplitude under different half-axis ratios. It was found that the Orthogonal Anisotropic VSP exhibits alternating periodic, multi-periodic, and chaotic response motions with the superposition of modes. This theory can help to an in-depth understanding of VSP's vibration.
Acoustic tweezers can control target movement through the momentum interaction between an acoustic wave and an object. This technology has advantages over optical tweezers for in-vivo cell ...manipulation due to its high tissue penetrability and strong acoustic radiation force. However, normal cells are difficult to acoustically manipulate because of their small size and the similarity between their acoustic impedance and that of the medium. In this study, we use the heterologous expression of gene clusters to generate genetically engineered bacteria that can produce numerous sub-micron gas vesicles in the bacterial cytoplasm. We show that the presence of the gas vesicles significantly enhances the acoustic sensitivity of the engineering bacteria, which can be manipulated by ultrasound. We find that by employing phased-array-based acoustic tweezers, the engineering bacteria can be trapped into clusters and manipulated in vitro and in vivo via electronically steered acoustic beams, enabling the counter flow or on-demand flow of these bacteria in the vasculature of live mice. Furthermore, we demonstrate that the aggregation efficiency of engineering bacteria in a tumour is improved by utilizing this technology. This study provides a platform for the in-vivo manipulation of live cells, which will promote the progress of cell-based biomedical applications.
Fatigue cracking is a common form of flexible pavement distress, which generally starts and spreads through bitumen. To address this issue, self-healing elastomer (SHE) modified bitumens were ...elaborated to assess whether these novel materials can overcome the neat asphalt (NA) fatigue performance and whether the current failure definition, failure criterion, and fatigue-restoration criteria can fit their performance. All bitumens were subjected to short-term and long-term aging. Linear amplitude sweep (LAS) test, LAS with rest period (LASH), and simplified viscoelastic-continuum-damage (S-VECD) model were utilized to appraise the behavior of the mentioned bitumens. The results showed that maximum stored pseudo-strain energy (PSE) and tau (τ) × N (number of loading cycles) failure definitions exhibited high efficiency to accommodate the fatigue life of NA and SHE-modified bitumens. Both failure criteria identified that SHE-modified bitumen (containing 1% of SHE) showed the highest increment of fatigue performance (67.1%) concerning NA. The failure criterion based on total released PSE, in terms of the area under the released PSE curve, was the only failure concept with high efficiency (R
up to 0.999) to predict asphalt binder fatigue life. As well, the current framework to evaluate bitumen self-restoration failed to fully accommodate asphalt binder behavior, because bitumen with higher restoration could not exhibit greater fatigue performance. Consequently, a new procedure to assess this property including fatigue behavior was proposed, showing consistent results, and confirming that SHE-modified bitumen (containing 1% of SHE) exhibited the highest increment of fatigue performance (154.02%) after application of the rest period. Hence, the optimum SHE content in NA was 1%. Furthermore, it was found that a greater number of loading cycles to failure (Nf) did not ensure better fatigue performance and stored PSE influenced the bitumen fatigue behavior.
Electroactive microorganisms (EAMs) play important roles in biogeochemical redox processes and have been of great interest in the fields of energy recovery, waste treatment, and environmental ...remediation. However, the currently identified EAMs are difficult to be widely used in complex and diverse environments, due to the existence of poor electron transfer capability, weak environmental adaptability, and difficulty with engineering modifications, etc. Therefore, rapid and efficient screening of high performance EAMs from environments is an effective strategy to facilitate applications of microbial fuel cells (MFCs). In this study, to achieve efficient degradation of methyl orange (MO) by MFC and electricity harvest, a more efficient exoelectrogen Shewanella carassii-D5 that belongs to Shewanella spp. was first isolated from activated sludge by WO3 nanocluster probe technique. Physiological properties experiments confirmed that S. carassii-D5 is a Gram-negative strain with rounded colonies and smooth, slightly reddish surface, which could survive in media containing lactate at 30 °C. Moreover, we found that S. carassii-D5 exhibited remarkable MO degradation ability, which could degrade 66% of MO within 72 h, 1.7 times higher than that of Shewanella oneidensis MR-1. Electrochemical measurements showed that MFCs inoculated with S. carassii-D5 could generate a maximum power density of 704.6 mW/m2, which was 5.6 times higher than that of S. oneidensis MR-1. Further investigation of the extracellular electron transfer (EET) mechanism found that S. carassii-D5 strain had high level of c-type cytochromes and strong biofilm formation ability compared with S. oneidensis MR-1, thus facilitating direct EET. Therefore, to enhance indirect electron transfer and MO degradation capacity, a synthetic gene cluster ribADEHC encoding riboflavin synthesis pathway from Bacillus subtilis was heterologously expressed in S. carassii-D5, increasing riboflavin yield from 1.9 to 9.0 mg/g DCW with 1286.3 mW/m2 power density output in lactate fed-MFCs. Furthermore, results showed that the high EET rate endowed a faster degradation efficient of MO from 66% to 86% with a maximum power density of 192.3 mW/m2, which was 1.3 and 1.6 times higher than that of S. carassii-D5, respectively. Our research suggests that screening and engineering high-efficient EAMs from sludge is a feasible strategy in treating organic pollutants.
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The respiratory syncytial virus (RSV) is the main cause of bronchiolitis in infants and interferon (IFN) α is a commercial antiviral drug. The nebulization of IFN α1b could be a viable treatment ...method. In this study, the therapeutic effects and safety of IFN α1b delivery via nebulization in infant bronchiolitis were investigated in this multi-center prospective study.
Bronchiolitis patients admitted to 22 hospitals who met the inclusion criteria were enrolled and randomly allocated to four groups: control, IFN Intramuscular Injection, IFN Nebulization 1 (1 μg/kg), and IFN Nebulization 2 (2 μg/kg) groups. All patients were observed for 7 days. The therapeutic effects and safety of different IFN delivery doses and delivery modes were evaluated. Coughing severity change, as scored by the researchers and parents, between days 1 and 3 was significantly different between the IFN Nebulization 2 and control groups. Lowell wheezing score change between days 3 and 5 was significantly different between IFN Nebulization 1 and control groups. There were no significant differences among the four groups regarding the number of consecutive days with fever, three-concave sign, fatigue and sleepiness, and loss of appetite. There were no cases of severe complications, no recurrence of fever, and no regression of mental status.
IFN-α1b could more effectively alleviate coughing and wheezing in bronchiolitis. IFN-α1b nebulization had significant advantages in shortening the duration of wheezing and alleviating coughing.
, the pathogen causing African sleeping sickness (trypanosomiasis) in humans, causes debilitating diseases in many regions of the world, but mainly in African countries with tropical and subtropical ...climates. Enormous efforts have been devoted to controlling trypanosomiasis, including expanding vector control programs, searching for novel anti-trypanosomial agents, and developing vaccines, but with limited success. In this study, we systematically investigated the effect of graphene quantum dots (GQDs) on trypanosomal parasites and their underlying mechanisms. Ultrasmall-sized GQDs can be efficiently endocytosed by
and with no toxicity to mammalian-derived cells, triggering a cascade of apoptotic reactions, including mitochondrial disorder, intracellular reactive oxygen species (ROS) elevation, Ca
accumulation, DNA fragmentation, adenosine triphosphate (ATP) synthesis impairment, and cell cycle arrest. All of these were caused by the direct interaction between GQDs and the proteins associated with cell apoptosis and anti-oxidation responses, such as trypanothione reductase (TryR), a key protein in anti-oxidation. GQDs specifically inhibited the enzymatic activity of TryR, leading to a reduction in the antioxidant capacity and, ultimately, parasite apoptotic death. These data, for the first time, provide a basis for the exploration of GQDs in the development of anti-trypanosomials.
A full understanding of bitumen fatigue cracking behavior is extremely important as this phenomenon has a considerable influence on bituminous pavement performance. The current framework for ...assessing this asphalt binder property is inconsistent in ranking bitumen fatigue performance in terms of the failure definition and damage characteristic curve (DCC) analysis. This study used four different types of asphalt binders: neat asphalt (NA), self-healing thermoplastic polyurethane (STP)-modified bitumen, self-healing poly (dimethyl siloxane) crosslinked with urea bond (IPA1w)-modified bitumen, and styrene–butadiene–styrene (SBS)-modified bitumen (SBSB). All the bitumens were subjected to short-term and long-term aging, and they were also tested by utilizing the linear amplitude sweep (LAS) test and the simplified viscoelastic continuum damage (S-VECD) model. LAS and S-VECD procedures were used to apply the newly proposed and current frameworks in order to analyze bitumen performance. The current framework showed that the bitumens that used a higher number of loading cycles (N) to reach their failure points (Nf) failed to exhibit greater fatigue performances in terms of DCC analysis. The developed framework (mainly based on the damage intensity S instead of N) was used to solve the inconsistency between the failure definition and DCC assessment in ranking bitumen performance. Additionally, the current framework (failure criterion) presented two R2 values below 0.1, but the developed framework (failure criterion) showed that all R2 values were greater than 0.9. The developed framework represents a turning point because, for the first time, this type of procedure is mainly being based on S instead of N. Although further tests are needed to confirm its efficiency, it eliminates the inconsistency between the failure definition and DCC assessment.
The excessive consumption of fossil fuels causes massive emission of CO
, leading to climate deterioration and environmental pollution. The development of substitutes and sustainable energy sources ...to replace fossil fuels has become a worldwide priority. Bio-electrochemical systems (BESs), employing redox reactions of electroactive microorganisms (EAMs) on electrodes to achieve a meritorious combination of biocatalysis and electrocatalysis, provide a green and sustainable alternative approach for bioremediation, CO
fixation, and energy and chemicals production. EAMs, including exoelectrogens and electrotrophs, perform extracellular electron transfer (EET) (
, outward and inward EET), respectively, to exchange energy with the environment, whose rate determines the efficiency and performance of BESs. Therefore, we review the synthetic biology strategies developed in the last decade for engineering EAMs to enhance the EET rate in cell-electrode interfaces for facilitating the production of electricity energy and value-added chemicals, which include (1) progress in genetic manipulation and editing tools to achieve the efficient regulation of gene expression, knockout, and knockdown of EAMs; (2) synthetic biological engineering strategies to enhance the outward EET of exoelectrogens to anodes for electricity power production and anodic electro-fermentation (AEF) for chemicals production, including (i) broadening and strengthening substrate utilization, (ii) increasing the intracellular releasable reducing equivalents, (iii) optimizing
-type cytochrome (
-Cyts) expression and maturation, (iv) enhancing conductive nanowire biosynthesis and modification, (v) promoting electron shuttle biosynthesis, secretion, and immobilization, (vi) engineering global regulators to promote EET rate, (vii) facilitating biofilm formation, and (viii) constructing cell-material hybrids; (3) the mechanisms of inward EET, CO
fixation pathway, and engineering strategies for improving the inward EET of electrotrophic cells for CO
reduction and chemical production, including (i) programming metabolic pathways of electrotrophs, (ii) rewiring bioelectrical circuits for enhancing inward EET, and (iii) constructing microbial (photo)electrosynthesis by cell-material hybridization; (4) perspectives on future challenges and opportunities for engineering EET to develop highly efficient BESs for sustainable energy and chemical production. We expect that this review will provide a theoretical basis for the future development of BESs in energy harvesting, CO
fixation, and chemical synthesis.
The mechanical principle of the Vierendeel Sandwich Plate is to excavate the web of the thick plate evenly to reduce the dead weight of the structure. It is suitable for large span building roof ...structure. The plate is composed of surface plate, upper rib, lower rib and short column (shear key). The governing equations of the Vierendeel Sandwich Plate are established by the variational method. The stress is regarded as an independent variable, the energy function is established, and the stress result is taken as a constraint condition by using Lagrange multipliers. The deflection equation of the Vierendeel Sandwich Plate can be obtained in a similar form to that obtained by Reissner and Liaw. An example is given to verify the feasibility and accuracy of the proposed method. The results show that by considering the membrane force of the equivalent plate and redefining the physical constants of the Vierendeel Sandwich Plate, the existing solutions of the Reissner equation for single layer sandwich with an isotropic core or Liaw equation for a multi-layer sandwich with an orthotropic core can be extended to the Vierendeel Sandwich Plate. The developed theory is an extension of the theory given in the sandwich plate.
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