Properties of Fiber-Reinforced Geopolymer Mortar Using Coal Gangue and Aeolian Sand.

Geopolymers, as a novel cementitious material, exhibit typical brittle failure characteristics under stress. To mitigate this brittleness, fibers can be incorporated to enhance toughness. This study investigates the effects of varying polypropylene fiber (PPF) content and fiber length on the flowability, mechanical properties, and flexural toughness of coal gangue-based geopolymers. Microstructural changes and porosity variations within the Fiber-Reinforced Geopolymer Mortar(GMPF) matrix were observed using scanning electron microscope (SEM) and Low field NMR(LF-NMR) to elucidate the toughening mechanism of PPF-reinforced geopolymers. The introduction of fibers into the geopolymer matrix demonstrated an initial bridging effect in the viscous geopolymer slurry, with a 3.0 vol% fiber content reducing fluidity by 5.6%. Early mechanical properties of GMPF were enhanced with fiber addition; at 1.5 vol% fiber content and 15 mm length, the 3-day flexural and compressive strengths increased by 30.81% and 17.4%, respectively. Furthermore, polypropylene fibers significantly improved the matrix's flexural toughness, which showed an increasing trend with higher fiber content. At a 3.0 vol% fiber content, the flexural toughness index increased by 198.35%. The data indicated that a fiber length of 12 mm yielded the best toughening effect, with an 84.03% increase in the flexural toughness index. SEM observations revealed a strong interfacial bond between fibers and the matrix, with noticeable damage on the fiber surface due to frictional forces, and fiber pull-out being the predominant failure mode. Porosity testing results indicated that fiber incorporation substantially improved the internal pore structure of the matrix, reducing the median pore diameter of mesopores and converting mesopores to micropores. Additionally, the number of harmless and less harmful pores increased by 23.01%, while the number of more harmful pores decreased by 30.43%.

A Semisolid Micromechanical Beam Steering System Based on Micrometa-Lens Arrays.

Optical beam steerers have been widely employed for information acquisitions. Numerous beam steering schemes have been developed, and each of them can satisfy practical requirements for certain scenarios. However, there is still a lack of a comprehensive approach that is able to balance all of the critical technical parameters for wide range of applications. Here, a semisolid micromechanical beam steering system based on micrometa-lens arrays (MMLAs) is demonstrated. It is operated by manipulating the probe beam over two sets of decentered MMLAs potentially driven by high-speed piezo-electric motors. Small f-numbers, well-corrected aberration, and easy lateral reproduction of micrometa-lenses optimize the overall technical parameters. As a proof-of-concept, we implement such a device exhibiting diffraction-limited resolution within a large field of view of 30° × 30°. A three-dimensional depth sensing is also performed to demonstrate its potential in light detection and ranging applications.

Simulation-Based Optimization of a Multiple Gas Feed Sweetening Process.

For an energy-intensive sweetening process, it is common that sour gases from different sources are sent to a single sweetening plant in industries. In our previous work, a multiple gas feed sweetening process was proposed, which can simultaneously improve the purity of H2S and reduce the energy consumption of the plant. This study aims to develop the superstructure of that process and use a simulation-based optimization framework with Aspen HYSYS as the process simulator and particle swarm optimization algorithm as the optimizer. In addition, by taking full advantage of the robustness of the built-in algorithm of the simulator, the convergence of the model is improved; meanwhile, simplification of the process and reduction of the optimization time are accessible with the proposed design specifications and assumptions. For a convergence-difficult column, a stepwise convergence adjustment was used to ensure their convergence. Based on this, the robustness and effectiveness of the method is proven through a case study, and it can also provide guidance for model selection, process simplification, and optimization of the same type of absorption process.

Magnetically Enhanced Liquid SERS for Ultrasensitive Analysis of Bacterial and SARS-CoV-2 Biomarkers.

In this work, it is shown that surface-enhanced Raman scattering (SERS) measurements can be performed using liquid platforms to perform bioanalysis at sub-pM concentrations. Using magnetic enrichment with gold-coated magnetic nanoparticles, the high sensitivity was verified with nucleic acid and protein targets. The former was performed with a DNA fragment associated with the bacteria Staphylococcus aureus, and the latter using IgG antibody, a biomarker for COVID-19 screening. It is anticipated that this work will inspire studies on ultrasensitive SERS analyzers suitable for large-scale applications, which is particularly important for in vitro diagnostics and environmental studies.

Modified Group Contribution Scheme to Predict the Glass-Transition Temperature of Homopolymers through a Limiting Property Dataset.

Previous studies on glass-transition temperature (T g) prediction mainly focus on developing diverse methods with higher regression accuracy, but very little attention has been paid to the dataset. Generally, a large range of T g values of a specified polymer could be found in the literature but which one should be selected into a dataset merely depends on the implicit preference rather than a recognized and clear criterion. In this paper, limiting glass-transition temperature (T g(∞)), a constant value obtained at the infinite number-average molecular weight M n, was validated to be an adequate bridge index in the T g prediction models. Furthermore, a new dataset containing 198 polymers was established to predict T g(∞) using the improved group contribution method and it showed a good correlation (R 2 = 0.9925, adjusted R 2 = 0.9894). The method could also generate T g-M n curves by introducing the T g(∞) function and provide more information to polymer scientists and engineers for material selection, product design, and synthesis.

Normal-Incidence-Excited Strong Coupling between Excitons and Symmetry-Protected Quasi-Bound States in the Continuum in Silicon Nitride-WS2 Heterostructures at Room Temperature.

Room-temperature strong coupling between quasi-bound states in the continuum (q-BIC) of a silicon nitride metasurface and excitons in a WS2 monolayer is investigated in detail by both numerical simulations and theoretical calculations. The strong coupling between the q-BIC mode and excitons leads to a remarkable spectral splitting and typical anticrossing behavior of the Rabi splitting, which can be realized in the absorption spectra by varying the grating thickness and asymmetry parameter of the silicon-nitride metasurface, respectively. In addition, both the line width of the q-BIC mode and local electric field enhancement are found to affect the strong coupling, which needs to be considered in detail in q-BIC metasurface designs. This work provides a possible way to enhance light-matter interactions in transition metal dichalcogenides monolayers and pave the way for future quantum and nanophotonic applications.

Upconversion enhancement by a dual-resonance all-dielectric metasurface.

Upconversion nanoparticles (UCNPs) have drawn much attention in the past decade due to their superior physicochemical features and great potential in biomedical and biophotonic studies. However, their low luminescence efficiency often limits their applications. Here, we demonstrated a dual-resonance all-dielectric metasurface to enhance the signals emitted by upconversion nanoparticles (NaYF4:Yb/Tm). An averaged upconversion signal enhancement of around 400 times is detected experimentally. The electric and magnetic dipole resonances of the metasurface are designed to enhance the local excitation field and the quantum efficiency of the upconversion nanoparticles, respectively. Furthermore, the collection efficiency is enhanced due to the directional emission of the UCNPs on the metasurface. Our approach provides a powerful tool to extend the sensing application potential of upconversion nanoparticles.

Smarter than others? Conjectures in lowest unique bid auctions.

Research concerning various types of auctions, such as English auctions, Dutch auctions, highest-price sealed-bid auctions, and second-price sealed-bid auctions, is always a topic of considerable interest in interdisciplinary fields. The type of auction, known as a lowest unique bid auction (LUBA), has also attracted significant attention. Various models have been proposed, but they often fail to explain satisfactorily the real bid-distribution characteristics. This paper discusses LUBA bid-distribution characteristics, including the inverted-J shape and the exponential decrease in the upper region. The authors note that this type of distribution, which initially increases and later decreases, cannot be derived from the symmetric Nash equilibrium framework based on perfect information that has previously been used. A novel optimization model based on non-perfect information is presented. The kernel of this model is the premise that agents make decisions to achieve maximum profit based on imaginary information or assumptions regarding the behavior of others.

New perspectives on chinese herbal medicine (zhong-yao) research and development.

Synthetic chemical drugs, while being efficacious in the clinical management of many diseases, are often associated with undesirable side effects in patients. It is now clear that the need of therapeutic intervention in many clinical conditions cannot be satisfactorily met by synthetic chemical drugs. Since the research and development of new chemical drugs remain time-consuming, capital-intensive and risky, much effort has been put in the search for alternative routes for drug discovery in China. This narrative review illustrates various approaches to the research and drug discovery in Chinese herbal medicine. Although this article focuses on Chinese traditional drugs, it is also conducive to the development of other traditional remedies and innovative drug discovery.

Moxibustion for breech version: a randomized controlled trial.

OBJECTIVE: To estimate the efficacy of moxibustion between 34 and 38 weeks of gestation to facilitate the cephalic version of fetuses in breech presentation and the acceptability of this method by women. METHODS: We conducted a randomized controlled trial in a Swiss university hospital maternity unit. We proposed to stimulate the acupoint BL 67 by moxibustion daily for 2 weeks for 212 consenting women between 34 and 36 weeks of gestation with a single fetus in breech presentation. We did the intervention three times weekly in the hospital and a teaching session and information leaflet on the technique for additional daily therapy at home. The control group received expectant management care. The availability of external cephalic version was maintained for both groups. The main outcome measure was the comparison of the proportion of women with cephalic presentation at delivery. RESULTS: Baseline characteristics were similar between groups, except more nulliparous women were randomized to moxibustion. The percentage of versions was similar between groups: 18% in the moxibustion group compared with 16% in the control group (relative risk 1.12, 95% confidence interval 0.62 to 2.03). Adjustment for the imbalance in parity did not change these results. The frequency of cesarean delivery was similar (64% compared with 58% in the moxibustion group and the control group, respectively). Acceptability of the intervention and women's perceptions of moxibustion were favorable. CONCLUSION: We observed no beneficial effect of moxibustion to facilitate the cephalic version of fetuses in breech presentation. Despite this lack of proven effectiveness, women had positive opinions on the intervention. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov,NCT00890474. LEVEL OF EVIDENCE: I.

Side-effects of moxibustion for cephalic version of breech presentation.

OBJECTIVES: Moxibustion, a Traditional Chinese Medicine technique related to acupuncture, was proposed to facilitate cephalic version of breech presentation. Several trials were conducted to evaluate the efficacy, but there are few reports on the safety of moxibustion. Our objective was to assess the side-effects and acceptability of this intervention. DESIGN: We are conducting a randomized controlled trial to evaluate the efficacy of moxibustion for breech version. The first 12 participants randomized in the moxibustion group had additional fetal surveillance by electronic monitoring. SUBJECTS: Pregnant women with a fetus in breech presentation are included in the trial between 34 and 36 weeks of gestation. INTERVENTIONS: We performed a cardiotocogram during 10 minutes before, 20 minutes during, and 10 minutes after each session. A maximum of 9 sessions were scheduled every other day, and stopped when cephalic version was diagnosed. The recordings were assessed by 3 independent readers using the Fischer scoring system. OUTCOME MEASURES: Fetal well-being was evaluated by the cardiotocogram; effect on the mother was evaluated by blood pressure recorded before and after each session; maternal views, contractions, and perceived changes in fetal movements were assessed using a questionnaire. RESULTS: A total of 65 cardiotocograms were analyzed. All scores were considered as normal, being at 8 or more on a 0-10 scale. Acceptability for the women and compliance to the intervention were good. No significant maternal or fetal side-effect was observed. CONCLUSIONS: We have not detected alterations of fetal and maternal well-being or other side-effects associated with moxibustion applied to the BL 67 for cephalic version of breech presentations. Moxibustion appears to be safe for both the mother and the fetus.

Matrix metalloproteinases and their specific tissue inhibitors in menstruation.

The timely breakdown of extracellular matrix is essential for menstruation. Matrix metalloproteinases, which are able to degrade virtually all components of the extracellular matrix, are spatiotemporally expressed in the cyclic endometrium. The expression of most matrix metalloproteinases is regulated transcriptionally and their proteolytic activities are precisely controlled. The balance between matrix metalloproteinases and their specific tissue inhibitors is believed to be crucial for menstruation. This review focuses on the roles of matrix metalloproteinases and their tissue inhibitors in the initiation of menstruation and on the regulation of matrix metalloproteinase expression and activation. For example, the function of matrix metalloproteinases and their tissue inhibitors in endometrial re-epithelialization and angiogenesis during endometrial regeneration, when cell migration is facilitated to ensure endometrial repair, is discussed. This and other processes, although not fully resolved, serve to illustrate the involvement of matrix metalloproteinases and their tissue inhibitors in the process of menstruation.