High-Order Ca(II)–Chloro Complexes in Mixed CaCl₂–LiCl Aqueous Solution: Insights from Density Functional Theory and Molecular Dynamics Simulations

In this study, the structural characteristics of high-coordinated Ca–Cl complexes present in mixed CaCl₂–LiCl aqueous solution were investigated using density functional theory (DFT) and molecular dynamics (MD) simulations. The DFT results show that [CaCl_<i>x</i>]^2–<i>x</i> (<i>x</i> = 4–6) clusters are quite unstable in the gas phase, but these clusters become metastable when hydration is considered. The MD simulations show that high-coordinated Ca–chloro complexes are possible transient species that exist for up to nanoseconds in concentrated (11.10 mol·kg^–1) Cl^– solution at 273 and 298 K. As the temperature increases to 423 K, these high-coordinated structures tend to disassociate and convert into smaller clusters and single free ions. The presence of high-order Ca–Cl species in concentrated LiCl solution can be attributed to their enhanced hydration shell and the inadequate hydration of ions. The probability of the [CaCl_<i>x</i>]^2–<i>x</i>_aq (<i>x</i> = 4–6) species being present in concentrated LiCl solution decreases greatly with increasing temperature, which also indicates that the formation of the high-coordinated Ca–Cl structure is related to its hydration characteristics

Toward an Intensive Longitudinal Understanding of Activated Sludge Bacterial Assembly and Dynamics

Temporal microbial community studies have broadened our knowledge of the dynamics and correlations among microbes in both natural and artificial engineering systems. Using activated sludge as a model system, we utilized the intensive longitudinal sampling method to identify overlooked diversity and the hidden dynamics of microbes, detect cross-associations among microbes after detrending, and reveal the central microbial dynamics during sludge bulking and foaming. We discovered that the accumulative alpha diversity in activated sludge sampled daily over 392 days could be as high as 14 000 OTUs, and that the bacterial community dynamics followed a gradual succession, drifting away from the initial observed day and displaying a significant time-dependent trend. Cross-associations among bacteria were modulated after removing potential spurious correlations based on autocorrelation in microbial time series. Moreover, clusters of bacteria displaying rapid turnover were discovered during the beginning, ongoing, and fading of sludge bulking and foaming, and their physicochemical parameters are resolved. These identified groups of bacteria and their related environmental factors could potentially supply clues to form hypotheses for treating operational problems, such as sludge bulking and foaming

Bilateral changes in afterhyperpolarization duration of spinal motoneurones in post-stroke patients

<div><p>This paper extends the observations presented in the previously published work on the afterhyperpolarization (AHP) duration changes in motoneurones (MNs) on the paretic (more affected) side of 11 post-stroke patients by the same analysis on the non-paretic (less-affected) side. The estimated AHP duration for patients’ MNs supplying more-affected muscles was significantly longer than control values and the elongation decreased with patient age and disorder duration. For MNs supplying less-affected muscles, dependency of AHP duration on age was closer to the control data, but the scatter was substantially bigger. However, the AHP duration estimate of less-affected MNs tended to be longer than that of controls in the short time elapsed since the stroke, and shorter than controls in the long time. Our results thus suggest that the spinal MNs on both sides respond to the cerebral stroke rapidly with prolongation of AHP duration, which tends to normalize with time, in line with functional recovery. This suggestion is in concert with the published research on post-stroke changes in brain hemispheres. To our knowledge, these dependencies have never been investigated before. Since the number of our data was limited, the observed trends should be verified in a larger sample of patients and such a verification could take into account the suggestions for data analysis that we provide in this paper. Our data are in line with the earlier published research on MN firing characteristics post-stroke and support the conclusion that the MUs of the muscles at the non-paretic side are also affected and cannot be considered a suitable control for the MUs on the paretic side.</p></div

Patient characteristics.

<p>Patient characteristics.</p

Distance ΔTI for less- and more-affected MNs, plotted vs. disorder duration.

<p>Explanation of symbols as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0189845#pone.0189845.g002" target="_blank">Fig 2</a>, except for 3 outliers of more-affected MNs for patients older than 55 years (triangles down). Dashed horizontal lines indicate mean values of Δ<i>TI</i> for short and long time after stroke.</p

AHP duration estimation.

<p>A) an example of data from a control subject: blue line, interspike intervals, blue circles, their moving average, orange diamonds, mean firing rate (inverse of ISI moving average), green line, absolute value of consecutive difference, all plotted vs. time. Note different scale for firing rate (right axis); B) green circles, SD(MISI) plot, lines fitted to the linear fragments of the plot. Their intersection determines the transition interval, which is an estimate of AHP duration (arrow); blue line, number of data in bins, right axis.</p

Additional file 1: S1. of Catalogue of antibiotic resistome and host-tracking in drinking water deciphered by a large scale survey

Data filtration. S2. Illumina MiSeq sequencing for 16S rRNA genes. S3. Co-occurrence patterns among ARGs. Table S1. Basic information about drinking water samples. Table S2. Information about 16S rRNA gene analysis in drinking water samples. Table S3. The primers (including barcode, pad, and linker) used for 16S rRNA gene amplification. Table S4. Detected ARG types and corresponding abundances in drinking water. Table S5. Detected ARG subtypes and corresponding abundances in drinking water. Table S6. The resistance level in drinking water samples. Table S7. Abundance and frequency of ARG types in drinking water samples. Table S8. Co-occurring ARGs subtypes of network modules. Table S9. Basic information about 56 environmental samples for comparison of ARGs with drinking water samples. Table S10. Occurrence of 9 generalist ARG subtypes that were prevalent in drinking water. Table S11. Assembly statistics for drinking water metagenomic sequencing data. Table S12. Types and subtypes of ARGs carried by ACCs and their occurrence in drinking water. Table S13. Bacterial taxonomy of ARG-carrying contigs in the lowest annotation level and ARGs they carried. Table S14. Bacterial OTUs and their abundances in drinking water. Figure S1. Collection locations of drinking water samples. Figure S2. Cluster analysis of drinking water metagenomes based on abundance of ARG subtypes (Euclidean). Figure S3. Abundance of the top 50 ARG subtypes detected in tap water samples. Figure S4. Correlation-based network statistical analysis reveals co-occurrence patterns among ARG subtypes. Figure S5. Two-dimensional principal coordinate analysis plots show the ARG composition differences among the 81 environmental samples from 8 ecosystems. Figure S6. Two-dimensional principal coordinate analysis plots show the microbial community difference among tap water samples. (ZIP 3889 kb

Boosting Antibacterial Photodynamic Therapy in a Nanosized Zr MOF by the Combination of Ag NP Encapsulation and Porphyrin Doping

Antibacterial photodynamic therapy (aPDT) is regarded as one of the most promising antibacterial therapies due to its nonresistance, noninvasion, and rapid sterilization. However, the development of antibacterial materials with high aPDT efficacy is still a long-standing challenge. Herein, we develop an effective antibacterial photodynamic composite UiO-66-(SH)2@TCPP@AgNPs by Ag encapsulation and 4,4′,4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP) dopant. Through a mix-and-match strategy in the self-assembly process, 2,5-dimercaptoterephthalic acid containing –SH groups and TCPP were uniformly decorated into the UiO-66-type framework to form UiO-66-(SH)2@TCPP. After Ag(I) impregnation and in situ UV light reduction, Ag NPs were formed and encapsulated into UiO-66-(SH)2@TCPP to get UiO-66-(SH)2@TCPP@AgNPs. In the resulting composite, both Ag NPs and TCPP can effectively enhance the visible light absorption, largely boosting the generation efficiency of reactive oxygen species. Notably, the nanoscale size enables it to effectively contact and be endocytosed into bacteria. Consequently, UiO-66-(SH)2@TCPP@AgNPs show a very high aPDT efficacy against Gram-negative and Gram-positive bacteria as well as drug-resistant bacteria (MRSA). Furthermore, the Ag NPs were firmly anchored at the framework by the high density of –SH moieties, avoiding the cytotoxicity caused by the leakage of Ag NPs. By in vitro experiments, UiO-66-(SH)2@TCPP@AgNPs show a very high antibacterial activity and good biocompatibility as well as the potentiality to promote cell proliferation

Crystal structure, optical properties, and theory study of a 1-D bromoplumbate stabilized by <i>in situ</i> generated <i>N</i>-alkylated DABCO cation

<p>We report the exploration of the stabilization effect of the <i>in situ</i> generated <i>N</i>-alkylated DABCO (DABCO = 1,4-diazabicyclo[2.2.2]octane) cation in the family of bromoplumbates and a 1-D bromoplumbate, (Et₂DABCO)_2n(Pb₃Br₁₀)_n (<b>1</b>), has been prepared by solvothermal conditions. Optical diffuse reflectance determination shows the band gap of <b>1</b> is 3.69 eV, which manifests that <b>1</b> is a wide band gap semiconductor. Compared with the band gap of bulk PbBr₂ (3.84 eV), <b>1</b> exhibits 0.15 eV red shift of absorption edge. While for the reported iodo analogs of this compound, (MPDA)_2n(Pb₃I₁₀)_n and (Et₂DABCO)_2n(Pb₃I₁₀)_n, they exhibit 0.53 and 0.47 eV blue shift of the energy gaps compared with the measured value of 2.30 eV for bulk PbI₂, respectively. The photoluminescent study of <b>1</b> shows that it exhibits a broad emission band centered at 697 nm upon photoexcitation by 345 nm (amount to 3.59 eV). The calculated density of states manifests the theoretical value of the band gap of <b>1</b> is 3.422 eV and the origination of photoluminescence can be ascribed to the transition of bonding electrons of Br^– anion to the empty orbits of Pb(II) ion.</p

Nanopost-Guided Self-Organization of Dendritic Inorganic Salt Structures

The formation of hierarchical architectures is of fundamental importance and yet a relatively elusive problem concerning many natural and industrial processes. In this paper, a nanopost array platform, or a nanopost substrate, has been developed to address this issue through a model study of the drying structures of phosphate buffered saline (PBS) solution. Unlike on a plain surface, highly ramified salt structures are formed by simply allowing the nanopost substrate wetted with the salt solution to dry, a process that completes within minutes at room temperature. The branches of salt structures have similar shapes repeating at different length scales, ranging from ∼200 nm up to a few centimeters in length, covering a 2 × 2 cm² area patterned with nanoposts fabricated in photoresist via laser interference lithography (LIL). Scanning electromicrograph (SEM) images show that salt structures are formed around nanoposts, and characteristic features of these salt structures can be modulated and predicted based on the surface properties and geometrical arrangements of nanoposts, suggesting that nanoposts can be used to guide the organization and crystallization of salts. This nanopost-guided crystallization approach is robust, rapid, versatile, and amenable to real-time observation and mass production, providing a great opportunity for the study and creation of large-scale hierarchical structures