Springer最新文献

The second law of thermodynamics states that entropy production in macroscopic systems is non-negative, reaching zero only at thermodynamic equilibrium. As a corollary, this implies that the state trajectory of macroscopic systems is inherently time-irreversible under out-of-equilibrium conditions. However, over the past half-century, various studies have shown that this principle does not universally apply to the composition sample paths of certain isothermal reactive systems. Theoretical frameworks leading to this surprising observation primarily focus on perfectly homogeneous systems (often referred to as zero-dimensional systems), which inherently exclude the effects of local fluctuations. This oversimplification may account for the paradoxical theoretical predictions. In the absence of relevant experimental data, this paper seeks to explore this phenomenon through microscopic simulations.

We present results for single axial-vector and scalar meson pole contributions to the hadronic light-by-light scattering (HLbL) part of the muon’s anomalous magnetic moment. In the dispersive approach to these quantities (in narrow width approximation) the central inputs are the corresponding space-like electromagnetic transition form factors. We determine these directly using a functional approach to QCD by Dyson–Schwinger and Bethe–Salpeter equations in the very same setup we used previously to determine pseudo-scalar meson exchange ((pi ), (eta ) and (eta ')) as well as meson ((pi ) and K) box contributions. Particular care is taken to preserve gauge invariance and to comply with short distance constraints in both the form factors and the HLbL tensor. Our result for the contributions from a tower of axial-vector states including short distance constraints is (a_mu ^{text {HLbL}}[text {AV-tower+SDC}] = 24.8 ,(6.1) times 10^{-11}). For the combined contributions from (f_0(980), a_0(980), f_0(1370)) and (a_0(1450)) we find (a_mu ^{text {HLbL}}[text {scalar}] = -1.6 ,(5) times 10^{-11}).

Metal finishing sludges usually require proper disposal due to their high content of leachable harmful species such as heavy metals. This study proposed an efficient and green remediation approach for the S/S of hazardous metal finishing sludge by incorporation of activated carbon (AC) as a cement replacement. Mechanical strength and leaching properties of the treated sludge were investigated. Meanwhile, the immobilization mechanisms were discussed on the basis of X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive spectrometry (SEM–EDS). The effectiveness of the AC/cement binder in S/S was evaluated by comparing it to OPC alone. The experimental results showed that the addition of 10 wt.% of AC resulted in an improvement of the compressive and flexural strength at 28 days of curing by 13.5% and 10.2%, respectively. According to the TCLP test, the concentrations of heavy metals in the leachates of S/S specimens were within the corresponding regulations. From the pH-dependent leaching test, the release of the selected metals was strongly pH-dependent. AC replacement had a significant effect in the reduction of the metal’s leachability except for Zn. MLT leaching test indicated that the immobilization rate of heavy metals exceeded 97% for both binders. Linear regression analysis revealed that the leaching mechanism of heavy metals was dominated by diffusion. However, traces of surface wash-off and solubility were also detected. The SEM–EDS method demonstrated that heavy metals were stabilized through adsorption onto activated carbon.

The toxicity of arsenic (As) in drinking water poses a significant risk to public health, and its effective removal is essential to reduce the associated risks. Modified slow sand filter (SSF) has emerged as a promising decentralized water treatment method in developing countries due to its user friendliness, economic viability, and environment-friendly properties. The present study investigated the total arsenic removal efficiency and turbidity reduction in laboratory-scale SSF columns designed for a 60-day filtration period. For this purpose, SSF columns were modified with magnetic corncob biochar (MCCB) and zero-valent iron (ZVI) layers in different ratios. The characterization tests, including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD), were conducted before and after the filtration. Results revealed that the MCCB surface was porous with a honeycomb-like structure before adsorption, containing cave-like holes favourable for arsenic removal. Similarly, the ZVI surface exhibited a tabular and thread structure. The EDS results confirmed the presence of Fe in the MCCB and ZVI, indicating the magnetic properties of both adsorbents. Notably, maximum As removal efficiency of 80% was observed in SSF(b) with a 10 cm MCCB layer after 60 days, whereas SSF(d) with a 10 cm ZVI layer achieved 99% within just 10 days of filtration. In addition, SSF columns containing ZVI layers achieved a maximum turbidity removal of 98% and 99% after 10 days of filtration, while SSF(b) with a 10 cm MCCB layer reached a turbidity removal of 99.9% after 60 days. Statistical analyses indicated that these differences were significant (p < 0.05), demonstrating the superior efficacy of the ZVI-based SSF for arsenic removal and the strong performance of MCCB in turbidity reduction. Overall, SSF-amended MCCB and ZVI demonstrated effective removal of As and turbidity. The study suggests that the designed SSFs are durable and user-friendly filter made of locally avaible low-cost materials for water filtration.

We present a design of an acoustic levitator composed of 35 ultrasonic transducers operating at 40 kHz configured to form a spherical cavity. The acoustic radiation force measured experimentally in the center of the cavity is ({{varvec{F}}}_{rad}approx 9.6 mN), enough for levitating spheres as well as irregular particles of different materials of up to ~ 50 mg. Levitation tests have been performed with particles of different geometries and compositions, including liquid droplets and minerals relevant in studies of atmospheric aerosol and cosmic dust. This device has been deployed in the center of a polar nephelometer set-up to conduct studies of light scattering by irregular solid particles and liquid droplets. Test experiments have been carried out using a 1.5 mm diameter NBK- 7 glass sphere, for which three elements of the scattering matrix have been measured as functions of the scattering angle using a 647 nm diode laser. Mie theory calculations of the scattering matrix elements at this wavelength agree well with the measurements, demonstrating the functionality of the whole device.

Sediments are an important environmental matrix, considered as the fingerprint of water bodies, since they can incorporate pollutants that remain there for long periods of time. The Madin Dam is an important reservoir in Mexico and several studies have shown that the water of this reservoir is severely impacted by contamination, particularly by heavy metals, which endangers the health of hydrobionts and users of the resource. Thus, the objective of this study was to evaluate the embryotoxicity produced by the exposure of sediments and pore water from Madin Dam on Danio rerio. Sampling was conducted at four points in Madín Dam, analyzing the physicochemical properties of sediments and metal concentrations such as Al, Fe, Pb, Hg, and Cd. From these, the Contamination Factor (CF), Enrichment Factor (EF), and modified Contamination Degree (mCdeg) were calculated. Subsequently, zebrafish embryos were exposed to sediments and pore water, and median lethal concentrations (LC₅₀) were calculated. Finally, developmental alterations were assessed using the General Morphological Score (GMS), hatching rate and teratogenic effects at sublethal concentrations. Sediments caused higher mortality compared to pore water at all sampling points. Sediments near the tributaries of the San Juan and Tlanepantla rivers showed a higher percentage of damage, suggesting a deterioration in sediment quality due to contaminants washed in from these areas. According to the GMS, a similarity in developmental delay was observed in embryos exposed to sediments and pore water as well as pericardial edema and scoliosis, with a more pronounced effect in sediments from the Nuevo Madín location. The metal concentration order in sediments was Fe > Al > Pb > Cd > Hg, highlighting the importance of Pb, Cd, Fe and Al due to their contamination level. These findings emphasize the need for effective monitoring and addressing of pollution sources in Madín Dam sediments. This approach is crucial to safeguard environmental health of the reservoir and implement proactive measures aimed at mitigating associated negative impacts.

Diaryl urea-based compounds have attracted the attention of many researchers due to their potential as anticancer agents. Following our previous study on a series of diaryl urea compounds and implementation of the obtained structure activity relationship (SAR) analysis, a new set of derivatives were designed and synthesized. The synthesized compounds were subjected to evaluation for their in vitro antiproliferative activities against A549 and HT-29 cell lines. Among all, 6a emerged as the most potent antiproliferative agent with an IC₅₀ value of 15.28 and 2.566 µM against HT-29 and A549 cells, respectively. Comparing the activity of the newly designed and synthesized diaryl urea compounds 4a-b and 6a-e with those for the previously reported compounds 8a-b and 9a-f confirmed the importance of the substitution of amide groups instead of ester between the central and distal benzene rings of diaryl urea scaffold. The results of current study revealed that the substitution of proximal and distal benzene rings with chlorine and methyl groups, alongside the linear extension of molecules through the introduction of a methylene spacer group could enhance antiproliferative activity, which is in agreement with previously reported SAR analysis. Molecular docking simulations demonstrated that all designed compounds exhibit binding affinity to VEGFR-2 similar to that observed experimentally for sorafenib. The findings of this study may offer valuable insights for the further development of diaryl urea-based anticancer agents.

Graphical Abstract