In situ doping of epitaxial diamond with germanium by microwave plasma CVD in GeH4-CH4-H2 mixtures with optical emission spectroscopy monitoring.

We report the growth of Ge-doped homoepitaxial diamond films by microwave plasma CVD in GeH4-CH4-H2 gas mixtures at moderate pressures (70-100 Torr). Optical emission spectroscopy was used to monitor Ge, H, and C2 species in the plasma at different process parameters, and trends for intensities of those radicals, gas temperature, and excitation temperature, with variations of GeH4 or CH4 precursor concentrations, were investigated. The film deposited on (111)-oriented single crystal diamond substrates in a high growth rate regime revealed a strong emission of a germanium-vacancy (GeV) color center with a zero-phonon line at ≈604 nm wavelength in photoluminescence (PL) spectra, confirming the successful doping. The observed PL shift for the GeV defect is caused by stress in the films, as evidenced and quantified by Raman spectra. These results suggest that in situ doping with Ge using a GeH4 precursor is a convenient method of controlling the formation of GeV centers in epitaxial diamond films for photonic applications.

Spatiotemporal distributions of sulfonamide and tetracycline resistance genes and microbial communities in the coastal areas of the Yangtze River Estuary.

In this paper, water and sediments were sampled at eight monitoring stations in the coastal areas of the Yangtze River Estuary in summer and autumn 2021. Two sulfonamide resistance genes (sul1 and sul2), six tetracycline resistance genes (tetM, tetC, tetX, tetA, tetO, and tetQ), one integrase gene (intI1), 16 S rRNA genes, and microbial communities were examined and analyzed. Most resistance genes showed relatively higher abundance in summer and lower abundance in autumn. One-way analysis of variance (ANOVA) showed significant seasonal variation of some ARGs (7 ARGs in water and 6 ARGs in sediment). River runoff and WWTPs are proven to be the major sources of resistance genes along the Yangtze River Estuary. Significant and positive correlations between intI1 and other ARGs were found in water samples (P < 0.05), implying that intI1 may influence the spread and propagation of resistance genes in aquatic environments. Proteobacteria was the dominant phylum along the Yangtze River Estuary, with an average proportion of 41.7%. Redundancy analysis indicated that the ARGs were greatly affected by temperature, dissolved oxygen, and pH in estuarine environments. Network analysis showed that Proteobacteria and Cyanobacteria were the potential host phyla for ARGs in the coastal areas of the Yangtze River Estuary.

Conformational Analysis of 1,5-Diaryl-3-Oxo-1,4-Pentadiene Derivatives: A Nuclear Overhauser Effect Spectroscopy Investigation.

1,5-Diaryl-3-Oxo-1,4-Pentadiene derivatives are intriguing organic compounds with a unique structure featuring a pentadiene core, aryl groups, and a ketone group. This study investigates the influence of fluorine atoms on the conformational features of these derivatives in deuterated chloroform (CDCl3) solution. Through nuclear magnetic resonance (NMR) spectroscopy and quantum chemical calculations, we discerned variations in interatomic distances and established predominant conformer proportions. The findings suggest that the non-fluorinated entity exhibits a uniform distribution across various conformer groups. The introduction of a fluorine atom induces substantial alterations, resulting in the predominance of a specific conformer group. This structural insight may hold the key to their diverse anticancer activities, previously reported in the literature.

Halogen Bond-Involving Self-Assembly of Iodonium Carboxylates: Adding a Dimension to Supramolecular Architecture.

We designed 0D, 1D, and 2D supramolecular assemblies made of diaryliodonium salts (functioning as double σ-hole donors) and carboxylates (as σ-hole acceptors). The association was based on two charge-supported halogen bonds (XB), which occurred between IIII sites of the iodonium cations and the carboxylate anions. The sequential introduction of the carboxylic groups in the aryl ring of the benzoic acid added a dimension to the 0D supramolecular organization of the benzoate, which furnished 1D-chained and 2D-layered structures when terephthalate and trimesate anions, correspondingly, were applied as XB acceptors. The structure-directing XB were studied using DFT calculations under periodic boundary conditions and were followed by the one-electron-potential analysis and the Bader atoms-in-molecules topological analysis of electron density. These theoretical methods confirmed the existence of the XB and verified the philicities of the interaction partners in the designed solid-state structures.

Alkylimidazolium Protic Ionic Liquids: Structural Features and Physicochemical Properties.

We focus on a series of protic ionic liquids (PILs) with imidazolium and alkylimidazolium (1R3HIm, R=methyl, ethyl, propyl, and butyl) cations. Using the literature data and our experimental results on the thermal and transport properties, we analyze the effects of the anion nature and the alkyl radical length in the cation structure on the above properties. DFT calculations in gas and solvent phase provide further microscopic insights into the structure and cation-anion binding in these PILs. We show that the higher thermodynamic stability of an ion pair raises the PIL decomposition temperature. The melting points of the salts with the same cation decrease as the hydrocarbon radical in the cation becomes longer, which correlates with the weaker ion-ion interaction inthe ion pairs. A comparative analysis of the protic ILs and corresponding ILs (1R3MeIm) with the same radical (R) in the cation structure and the same anion has been performed. The lower melting points of the ILs with 1R3MeIm cations are assumed to result from the weakening of both the ion-ion interaction and the hydrogen bond.

A novel intra- and extracellular distribution pattern of elemental sulfur in Pseudomonas sp. C27-driven denitrifying sulfide removal process.

Pseudomonas sp. C27 can achieve the conversion of toxic sulfide to economical elemental sulfur (S0) with various electron acceptors. In this study the distribution pattern of S0 produced by C27 in denitrifying sulfide removal (DSR) process was explored. The SEM observation identified that the particle size of the biogenic S0 was at micron level. Strikingly, a novel distribution pattern of S0 was revealed that the produced S0 was not directly secreted extracellularly, but be stored temporarily in the cell interior. Pyrolysis at 65 °C for 20 min were recommended prior to S0 recovery, which could maximize the separation of extracellular polymeric substances (EPS) from C27. Furthermore, the effects of N/S molar ratio, initial sulfide concentration, and micro-oxygen condition were investigated to improve the production of S0 by C27. The highest S0 production was obtained at S/N of 3 and anaerobic condition seemed to favor the S0 production by C27. This study would provide a theoretical support for highly efficient sulfide removal as well as S0 recovery in sulfide-laden wastewater treatment.

Ion Pair Structures and Hydrogen Bonding in RnNH4-n Alkylammonium Ionic Liquids with Hydrogen Sulfate and Mesylate Anions by DFT Computations.

Density function theory calculations are employed to study the interaction of amines bearing different numbers of alkyl substituents of different sizes on the nitrogen atom with sulfuric and methanesulfonic acids. The proton affinities of the studied amines are calculated, and it is shown that the higher the value is, the more probable is its protonation. The most stable structures of the ion pairs resulting from the acid-base interaction are obtained and characterized. The geometric parameters of the ion pairs and the characteristics derived from the NBO and QTAIM analysis show that there are hydrogen bonding interactions between the cation and the anion. The hydrogen bonding character of the ion pairs and the strength of the interaction between the ions strongly depend on the nature of the cation itself. The interaction between the ions in the ion pairs weakens with the increase in the cation size. The trend of change in the structural parameters of the H-bonds and energetic characteristics in the cation series for the studied ion pairs is not dependent on the nature of the anion.

Quantum Chemical Modeling of the Structure and H Bonding in Triethanolammonium-Based Protic Ionic Liquids with Sulfonic Acids.

The results of electronic structure calculations based on density functional theory (DFT) for protic ionic liquids (PILs) consisting of triethanolammonium cation paired with anion of different sulfonic acids are reported. The influence of the anion nature on the structure and interactions in the ion pairs that are formed in these PILs is discussed in detail. Multiple H-bonding interactions exist between the protons in the NH/OH groups of the cation and different oxygen atoms of the acid anion in the ion pairs. The quantum theory of "atoms in molecules" has been used to estimate the individual contributions of each hydrogen bond to the stability of the ion pair. The hydrogen-bonding interactions in the ion pairs vary in their strength ranging from weak to moderately strong. In addition to these hydrogen bonds, there are other dispersion and electrostatic-dominant interactions that play an important role in the overall stability of PILs and their physicochemical properties. Aided by results from our previous DFT studies of triethanolammonium class of PILs with inorganic anions, these new data allow us to gain an improved understanding of the structure-property relationships in the studied ionic liquids. Close to linear correlation, in particular, has been found between the melting points and the binding energies of the cation and anion in the ion pairs.

Ab Initio Investigation of the Interionic Interactions in Triethylammonium-Based Protic Ionic Liquids: The Role of Anions in the Formation of Ion Pair and Hydrogen Bonded Structure.

The results of structural analysis and cation-anion interactions of 10 ion pairs and their relevance for the physicochemical properties of triethylammonium-based protic ionic liquids are reported. The calculations were mainly performed by dispersion corrected density functional theory method (B3LYP-GD3). It is shown that the dispersion correction is important in the evaluation of the interaction energies of these compounds. The role of anions in the formation of ion pairs and hydrogen-bonded structure are analyzed. To obtain a quantitative measure of the strength of H-bonds, the Bader's theory of atoms in molecule (AIM) was applied. The correlations between hydrogen bond lengths, their energies, and electron-topological parameters at the H···O bond critical point are presented.

Analyzing Boron in 9-12% Chromium Steels Using Atom Probe Tomography.

Small additions of boron can remarkably improve the long-term creep resistance of 9-12% Cr steels. The improvement has been attributed to boron segregation to grain boundaries during quenching, and subsequent boron incorporation into certain families of precipitates during tempering. However, the detailed mechanisms are not yet fully understood. Atom probe tomography (APT) is an excellent technique for gaining insights into boron distribution, however, in order to acquire accurate analysis of boron in 9-12% Cr steels using APT, there are several key challenges. In order to better understand and address these challenges, we developed a novel method for site-specific APT specimen preparation, which enables convenient preparation of specimens containing specifically selected grain boundaries positioned approximately perpendicular to the axis of the APT tip. Additionally, when analyzing boron at boundaries and in carbides (as diluted solute) and borides, a widening of the profile of boron distribution compared to other elements was repeatedly observed. This phenomenon is particularly analyzed and discussed in light of the evaporation field of different elements. Finally, the possible effects of detector dead-time on quantitative analysis of boron in metal borides are discussed. A simple method using 10B correction was used to obtain good quantification.

Novel Aminomethyl Derivatives of 4-Methyl-2-prenylphenol: Synthesis and Antioxidant Properties.

4-Methyl-2-prenylphenol (1) was synthesized from para-cresol and prenol, natural alcohol under the conditions of heterogeneous catalysis. A series of nine new aminomethyl derivatives with secondary and tertiary amino groups were obtained on the basis of compound 1. A comparative evaluation of their antioxidant properties was carried out using in vitro models. It was established that Mannich base with octylaminomethyl group has radical-scavenging activity, high Fe2+ -chelation ability as well as the ability to inhibit oxidative hemolysis of red blood cells.

Influence of Cation Size on the Structural Features and Interactions in Tertiary Alkylammonium Trifluoroacetates: A Density Functional Theory Investigation.

We present the results of electronic structure calculations based on density functional theory (DFT) in order to investigate the reactions of the interaction of tertiary alkylamines with alkyl groups of different sizes (triethyl, tributyl, dimethylethyl, and diisopropylethyl) with trifluoroacetic acid. We have obtained data on the affinity of the studied amines with a proton. It has been shown that amine interaction with the acid leads to proton transfer from the acid to the amine and formation of ions held together in the ion pair by electrostatic interaction and a very strong hydrogen bond. We have also investigated the energy profiles of the proton transfer from the tertiary alkylammonium cation to the trifluoroacetate anion within the ion pair and found different correlations between the geometric characteristics of the H-bond and the parameters obtained by the natural bond orbitals and quantum theory of atoms in molecules analyses. It has been established that the interionic interactions in these systems weaken as the length and the degree of cation alkyl chain branching increase. A good qualitative agreement between the theoretical results and the experimental data on physicochemical properties has been obtained.

The Nature of the Interactions in Triethanolammonium-Based Ionic Liquids. A Quantum Chemical Study.

Structural features and interionic interactions play a crucial role in determining the overall stability of ionic liquids and their physicochemical properties. Therefore, we performed high-level quantum-chemical study of different cation-anion pairs representing the building units of protic ionic liquids based on triethanolammonium cation and anions of sulfuric, nitric, phosphoric, and phosphorus acids to provide essential insight into these phenomena at the molecular level. It was shown that every structure is stabilized through multiple H bonds between the protons in the N-H and O-H groups of the cation and different oxygen atoms of the anion acid. Using atoms in molecules topological parameters and natural bond orbital analysis, we determined the nature and strength of these interactions. Our calculations suggest that the N-H group of the cation has more proton donor-like character than the O-H group that makes the N-H···O hydrogen bonds stronger. A close relation between the binding energies of these ion pairs and experimental melting points was established: the smaller the absolute value of the binding energy between ions, the lower is the melting point.

Ab Initio Study of Structural Features and H-Bonding in Alkylammonium-Based Protic Ionic Liquids.

The structural and energetic characteristics of protic ionic liquids (PILs) based on ethyl-, diethyl-, or triethylammonium cations with anions of phosphorus, trifluoroacetic, or p-toluenesulfonic acids have been investigated by density functional theory calculations at the B3LYP/6-31++G(d,p) level of theory. As a result of the interaction between acid and alkylamine, the H-bonded molecular complexes or H-bonded ion pairs have been obtained. The increasing number of ethyl groups attached to the nitrogen atom of amine and H-bond donor ability of acid causes a stronger H-bonding interaction leading to the formation of ion pairs. For all systems, the proton transfer between ion pairs and molecular complexes has been examined. Solvation effects have been also investigated using the solvent polarizable continuum model (CPCM).

Ab initio molecular dynamics study of H-bonding and proton transfer in the phosphoric acid-N,N-Dimethylformamide system.

Car-Parrinello molecular dynamics simulations of phosphoric acid (H3PO4)-N,N-dimethylformamide (DMF) mixtures over the whole composition range have been carried out. It has been found that the neutral molecules are the dominant species in this system. The concentration dependences of the average number of H-bonds per proton acceptor atom in P=O and C=O groups as well as per proton donor atom in DMFH+ ions towards phosphate species have been discussed. The H-bonding between components in all investigated mixtures of H3PO4 and DMF is possible. A significant fraction of the protonated DMF forms appears at phosphoric acid mole fraction higher than 0.37, indicating a high probability of proton transfer from phosphate species to oxygen atoms in C=O groups. The intermolecular proton transfer between phosphate species themselves is mainly observed when xH3PO4 > 0.19. Satisfactory agreement with available experimental data for structural characteristics of the investigated system was obtained.

Chromosome hydroxymethylation patterns in human zygotes and cleavage-stage embryos.

We report the sequential changes in 5-hydroxymethylcytosine (5hmC) patterns in the genome of human preimplantation embryos during DNA methylation reprogramming. We have studied chromosome hydroxymethylation and methylation patterns in triploid zygotes and blastomeres of cleavage-stage embryos. Using indirect immunofluorescence, we have analyzed the localization of 5hmC and its co-distribution with 5-methylcytosine (5mC) on the QFH-banded metaphase chromosomes. In zygotes, 5hmC accumulates in both parental chromosome sets, but hydroxymethylation is more intensive in the poorly methylated paternal set. In the maternal set, chromosomes are highly methylated, but contain little 5hmC. Hydroxymethylation is highly region specific in both parental chromosome sets: hydroxymethylated loci correspond to R-bands, but not G-bands, and have well-defined borders, which coincide with the R/G-band boundaries. The centromeric regions and heterochromatin at 1q12, 9q12, 16q11.2, and Yq12 contain little 5mC and no 5hmC. We hypothesize that 5hmC may mark structural/functional genome 'units' corresponding to chromosome bands in the newly formed zygotic genome. In addition, we suggest that the hydroxymethylation of R-bands in zygotes can be treated as a new characteristic distinguishing them from G-bands. At cleavages, chromosomes with asymmetrical hydroxymethylation of sister chromatids appear. They decrease in number during cleavages, whereas totally non-hydroxymethylated chromosomes become numerous. Taken together, our findings suggest that, in the zygotic genome, 5hmC is distributed selectively and its pattern is determined by both parental origin of chromosomes and type of chromosome bands - R, G, or C. At cleavages, chromosome hydroxymethylation pattern is dynamically changed due to passive and non-selective overall loss of 5hmC, which coincides with that of 5mC.

Cysteine-rich toxins from Lachesana tarabaevi spider venom with amphiphilic C-terminal segments.

Venom of Lachesana tarabaevi (Zodariidae, "ant spiders") exhibits high insect toxicity and serves a rich source of potential insecticides. Five new peptide toxins active against insects were isolated from the venom by means of liquid chromatography and named latartoxins (LtTx). Complete amino acid sequences of LtTx (60-71 residues) were established by a combination of Edman degradation, mass spectrometry and selective proteolysis. Three toxins have eight cysteine residues that form four intramolecular disulfide bridges, and two other molecules contain an additional cystine; three LtTx are C-terminally amidated. Latartoxins can be allocated to two groups with members similar to CSTX and LSTX toxins from Cupiennius salei (Ctenidae) and Lycosa singoriensis (Lycosidae). The interesting feature of the new toxins is their modular organization: they contain an N-terminal cysteine-rich (knottin or ICK) region as in many neurotoxins from spider venoms and a C-terminal linear part alike some cytolytic peptides. The C-terminal fragment of one of the most abundant toxins LtTx-1a was synthesized and shown to possess membrane-binding activity. It was found to assume amphipathic α-helical conformation in membrane-mimicking environment and exert antimicrobial activity at micromolar concentrations. The tails endow latartoxins with the ability to bind and damage membranes; LtTx show cytolytic activity in fly larvae neuromuscular preparations. We suggest a membrane-dependent mode of action for latartoxins with their C-terminal linear modules acting as anchoring devices.

A comparative cytogenetic study of miscarriages after IVF and natural conception in women aged under and over 35 years.

PURPOSE: To compare the frequency and the spectrum of karyotype abnormality in the first trimester miscarriages in women aged under and over 35 years, who conceived naturally (NC) and who conceived through in vitro fertilization (IVF). METHODS: Comparative analysis of cytogenetic data obtained by karyotyping of miscarriages in patients who conceived naturally, and who conceived through IVF. Patients were subcategorized by their age: <35 years (NC, n = 173; IVF, n = 108) and ≥ 35 years (NC, n = 107; IVF, n = 111). RESULTS: A total of 499 miscarriage karyotypes was analyzed. The spectrum and the relative proportions of different cytogenetic categories in karyotypically abnormal miscarriages differed neither between the NC and IVF patients aged <35 years, nor between the NC and IVF patients aged ≥ 35 years. In the patients aged <35 years, the incidence of abnormal miscarriage karyotype was lower in the IVF group (37.04 % vs 62.43%). In the patients aged ≥ 35 years, the incidence of miscarriages with cytogenetic pathology did not differ between the NC and the IVF group (75.70 % vs 58.56%). The lowest frequency of karyotypically abnormal miscarriages (29.82%) was detected in the young IVF-treated patients at <7 weeks of gestation. CONCLUSIONS: IVF does not increase the risk of a pregnancy loss because of abnormal embryonic karyotype, nor does it increase the preponderance for any specific type of cytogenetic abnormality in both patients aged under and over 35 years. In young IVF-treated women early pregnancy loss is generally caused by non-cytogenetic factors. Identification of a cytogenetically normal spontaneous abortion is clinically significant and reinforces the importance of developing an appropriate diagnosis and treatment strategies for IVF patients in order to reduce the risk of euploid pregnancy loss.

Influence of vegetation on heavy metal Cr release process from bottom sediment under unidirectional flows and regular waves.

As human activities become more intensive, a substantial number of heavy metals are discharged into estuarine or wetland environments. Due to the poor degradability, heavy metals are prone to adsorption and deposition on suspended particles in bottom sediments. Subsequently, under the influence of disturbances, there is a potential for their re-release, causing secondary pollution. To investigate the release process of the heavy metal Cr from sediment, laboratory experiments were conducted under both unidirectional flow and regular wave conditions. At the initial stage, the temporal trends of particulate (CrP) and dissolved (CrD) Chromium concentrations were both characterized by initial increments followed by stabilization and continuous escalation. Vertically, the stable concentrations of CrP and CrD increased with the presence of vegetation and the enhancement of hydrodynamics. The Elovich equation, pseudo-second-order kinetic equation, Double constant equation (Freundlich model), and parabolic diffusion equation were employed to predict the release process of CrD from bottom sediment. The Elovich equation proved most suitable for describing the release process of CrD, with an R2 exceeding 0.9. In order to assess the influence of vegetation on the Cr release process, the Stem-Reynolds were introduced to modify the Elovich equation. The final maximum error was 12 % (excluding the initial stage), which was much lower than that using the original Elovich equation (maximum error of 32 %). The study findings provide practical support for estuarine and wetland managers to formulate effective heavy metal management measures, which contribute to the conservation and sustainable management of aquatic ecosystems.

Predictions of heavy metal concentrations by physiochemical water quality parameters in coastal areas of Yangtze river estuary.

Due to the degradation-resistant and strong toxicity, heavy metals pose a serious threat to the safety of water environment and aquatic ecology. Rapid acquisition and prediction of heavy metal concentrations are of paramount importance for water resource management and environmental preservation. In this study, heavy metal concentrations (Cr, Ni, Cu, Pb, Zn, Cd) and physicochemical parameters of water quality including Temperature (Temp), pH, Oxygen redox potential (ORP), Dissolved oxygen (DO), Electrical conductivity (EC), Electrical resistivity (RES), Total dissolved solids (TDS), Salinity (SAL), Cyanobacteria (BGA-PE), and turbidity (NTU) were measured at seven stations in the Yangtze river estuary. Principal Component Analysis (PCA) and Spearman correlation analysis were employed to analyze the main factors and sources of heavy metals. Results of PCA revealed that the main sources of Cr, Ni, Zn, and Cd were steel industry wastewater, domestic and industrial sewage, whereas shipping and vessel emissions were typically considered sources of Pb and Cu. Spearman correlation analysis identified Temp, pH, ORP, EC, RES, TDS, and SAL as the key physicochemical parameters of water quality, exhibiting the strongest correlation with heavy metal concentrations in sediment and water samples. Based on these results, multiple linear regression as well as non-linear models (SVM and RF) were constructed for predicting heavy metal concentrations. The results showed that the results of the nonlinear model were more suitable for predicting the concentrations of most heavy metals than the linear model, with average R values of the SVM test set and RF test set being 0.83 and 0.90. The RF model showed better applicability for simulating the concentration of heavy metals along the Yangtze river estuary. It was demonstrated that non-linear research methods provided efficient and accurate predictions of heavy metal concentrations in a simple and rapid manner, thereby offering decision-making support for watershed managers.