Aggregation Ability Research Articles

Sealing Ability of Bioactive Root-End Filling Materials in Retro Cavities Prepared with Er,Cr:YSGG Laser and Ultrasonic Techniques.

The aim of this in vitro study was to compare the apical sealing ability of total fill bioceramic root repair material (BC-RRM) and mineral trioxide aggregate (MTA), regarding the retrograde preparation technique used: ultrasonic or erbium, chromium: yttrium, scandium, gallium, or garnet (Er,Cr:YSGG) laser. The study sample consisted of 48 human single-rooted teeth. After root-end resection, the samples were divided into two groups, according to the retrograde preparation technique used: Group 1: ultrasonic; Group 2: Er,Cr:YSGG laser. In each group, half of the retrograde cavities were filled with BC-RRM, and the other half were filled with MTA. The specimens were mounted in tubes and sterilized in plasma. The root canals were inoculated with Enterococcus faecalis, and the tubes were filled with fetal bovine serum, leaving the apical part of the root in the serum. After 30 days, the canals were sampled and cultured, and the colony forming units (CFUs) were counted with the additional polymerase chain reaction (PCR analysis). There was no significant difference between ultrasonic groups and the Er,Cr:YSGG-MTA group, regarding the number of CFUs (p > 0.05). The Er,Cr:YSGG-BC-RRM group showed the highest number of remaining viable bacteria (p < 0.001). Both filling materials filled in ultrasonic preparations presented similar sealing abilities. The BC-RRM showed more leakage when used in retro cavities prepared with the Er,Cr:YSGG laser.

Study of the effect of acetylsalicylic acid and a selective arginase II inhibitor KUD 975 on the correction of hemostatic disorders in experimental preeclampsia

Introduction: The disruption of the functional state of the vascular endothelium is among the main causes of pre­eclampsia, which is one of the most common causes of maternal and perinatal mortality. It can be enhanced by the humoral factors secreted by the activated platelets. The use of acetylsalicylic acid is an effective way to prevent pre­eclampsia. However, its ability to activate eNOS is a prerequisite for researching its ability to correct the disorders in developing preeclampsia, including by reducing the platelet activity. In this case its effect can be enhanced through increasing the bioavailability of L-arginine by using a selective arginase II inhibitor KUD 975. These facts were the prerequisite for conducting this study.&#x0D; Materials and methods: The study was conducted on 180 female Wistar rats weighing 250–300 g. Acetylsalicylic acid was used at a dose of 7 mg/kg/day and 10 mg/kg/day, KUD 975 – at a dose of 1 mg/kg/day and 3 mg/kg/day. Adenosine diphosphate (ADP, 6.5 microns), arachidonic acid (ASPI, 0.5 mM), and collagen (3.2 mcg/ml) were used as aggregation inducers.&#x0D; Results and discussion: ADMA-like preeclampsia simulation led to an increase in platelet aggregation ability when using all aggregation inducers. This is evidenced by an increase in a degree, rate of aggregation, and a shortened time of thrombus formation. The use of acetylsalicylic acid and a selective arginase II inhibitor KUD 975 led to a decrease in the aggregation ability of platelets and an increase in thrombosis time, while the combined administration of the studied agents showed a more pronounced effect.&#x0D; Conclusion: The data obtained while performing a series of experiments strongly indicate a promising outlook for using acetylsalicylic acid and a selective arginase II inhibitor KUD 975 in order to correct emerging disorders in preeclampsia.

Influence of nitrogen-poor wastewater on activated sludge aggregation and settling: Sequential responses of extracellular proteins and exopolysaccharides

To explore the mechanism by which the degree of wastewater nitrogen deficiency affects the aggregation and sedimentation of activated sludge, the structure, aggregation, sedimentation and thermodynamic properties of activated sludge and the composition, structure and properties of extracellular polymers under different influent nitrogen contents were examined. Hydrophobicity was the main factor affecting sludge aggregation. When nitrogen was limited (C/N = 100:2), the sludge aggregation ability decreased to 38.1 ± 1.1%, but with increases in extracellular protein (PN) content (89.8% increase) and hydrophobicity, the sludge aggregation ability returned to the level in the control phase. Under nitrogen deficiency (C/N = 100:0), the PN/exopolysaccharide (PS) decreased to 1.36 ± 0.09, and the increased hydrophilicity of PS led to a decrease in sludge aggregation ability (48.5 ± 1.0%) and a loose structure, which reduced sludge settling performance. In addition, PN and PS sequentially responded to changes in influent nitrogen content and played key roles in sludge aggregation. This study clarifies the mechanism by which the degree of wastewater nitrogen deficiency affects the aggregation and sedimentation of activated sludge from the perspective of extracellular polymers (EPS), which will help promote the further application of activated sludge processes.

Self-guided information for few-shot classification

Few-shot classification aims to identify novel categories using only a few labeled samples. Generally, the metric-based few-shot classification methods compare the feature embedding of Query samples (unlabeled samples) with Support samples (labeled samples) in a metric algorithm to predict which category the Query sample belongs to. Obtaining a good feature embedding for each sample in the feature extraction stage can improve the classification accuracy in the metric stage. Based on this, we design the Self-Guided Information Convolution (SGI-Conv), an improved convolution structure, which utilizes the high-level features to guide the network to extract the required discriminative features. To effectively utilize the feature embeddings of samples, we divide the metric network into multiple blocks and build a multi-layer graph convolutional network by sharing adjacent matrices. The multi-layer structure enhances the aggregation ability of graph convolution. Extensive experiments on multiple benchmark datasets demonstrate that our method has achieved competitive results on the few-shot classification tasks.

ПОСТЛУЧЕВЫЕ ИЗМЕНЕНИЯ СОДЕРЖАНИЯ В КРОВИ ТРОМБОЦИТОВ И ИХ ФУНКЦИОНАЛЬНОЙ АКТИВНОСТИ

The action of ionizing radiation on the body leads to the development of various pathological disorders in organs and tissues. In the first place are pathologies of the cardiovascular system. They are preceded by disorders in the blood system. There are general patterns in changes in the qualitative and quantitative composition of peripheral blood under the influence of ionizing radiation. Among cellular elements, platelets and their interaction with vascular endothelial cells play a leading role in changing the hemodynamic properties of blood. The angiotrophic function of platelets may be impaired due to changes in their number and/or functional activity. After irradiation at a dose of 1 Gy, phase changes in the number of platelets were observed in the blood of rats during the rehabilitation period. On the 3rd day of the post-radiation period, the concentration of platelets and the value of thrombocrit corresponded to those of the control group. On the 10th day, the number of platelets and the value of thrombocrit decreased in irradiated rats. In the long term after irradiation (30s and 90s), these indicators were restored to normal values. The distribution width of platelets and their average volume did not change during all the studied periods of the post-radiation period. After irradiation at a dose of 1 Gy, changes in the aggregation ability of platelets were noted when the aggregation inducer ADP was introduced at a low concentration (2.4 ± 10-6M). On the 3rd and 30th days, the irradiated sample was divided into two groups: individuals with a degree of platelet reactivity corresponding to the control, and with high reactivity. On the 10th day, among the platelets of irradiated individuals, a tendency to shift the indicators of the degree and rate of aggregation towards reduced aggregation activity prevails. In the long term (90th day) of the post-radiation period, the irradiated animals showed a prolongation of the period of change in the shape of platelets and a weakening of the reaction to aggregation inducers, which contributes to hemorrhagic manifestations. Thus, the data obtained indicate that in the short term after irradiation, the tendency to increased thrombus formation and the development of ischemic damage prevails, and in the long term (day 90), aggregation activity decreases and the risk of bleeding increases.

Influence of low air pressure on combined nitritation and anaerobic ammonium oxidation process

At high altitude, wastewater aeration efficiency is low, which is detrimental to nitrification in conventional biological nitrogen removal. The combined partial nitritation and anaerobic ammonium oxidation (CPNA) process requires little oxygen and can be appropriate in low-pressure conditions. As such, in this study, we investigated the effect of air pressure on CPNA using a laboratory-scale reactor. We found that low air pressure promoted the removal of total inorganic nitrogen (TIN), achieving a TIN removal rate of 43,000 mg·N/(kg·VSS·d). The secretion of extracellular polymeric substances under low air pressure was not significantly different from that under ordinary air pressure, indicating no adverse effects on microbial aggregation ability, stability, or settleability. The abundance of aerobic ammonia-oxidizing bacteria (AeAOB) increased from 0.2% to 5.6%, and the activity of anaerobic ammonia-oxidizing bacteria (AnAOB) enhanced, giving AeAOB and AnAOB a competitive advantage over nitrite-oxidizing bacteria, thus forming a microbial community structure favorable to the CPNA process. Our further analysis of the results of batch tests in serum bottles confirmed the positive effect of low air pressure on the anaerobic ammonium oxidation (anammox) process, with a 28.5% ± 1.9% improvement in the specific anammox rate at 70 kPa compared with 100 kPa. AnAOB activity increased, which was reflected in the intracellular heme content increasing from 0.56 ± 0.18 μmol/(g·VSS) at 100 kPa to 2.56 ± 0.20 μmol/(g·VSS) at 70 kPa. We clarified the CPNA-process-promoting effect of low air pressure, which shows potential for nitrogen removal in high-altitude regions.

Novel approach for tuning micellar characteristics and rheology of a sulfate-free anionic surfactant sodium cocoyl glycinate

Amino acid based mild and sulfate-free anionic surfactant, sodium cocoyl glycinate (SCGLY) forms spherical micellar aggregates in water. The mixed micellar characteristics of SCGLY has been studied in the presence of nonionic surfactants like cocamide diethanolamine (CDEA) and lauryl glucoside (LG). The ternary aqueous system of SCGLY/CDEA/LG depicts higher surface activity and stronger aggregation ability compared to corresponding single or binary surfactant systems as revealed by tensiometry. The effect of pH (5.5–6.5) and total surfactant concentration (14–18 wt%) on thickening of SCGLY/CDEA/LG system is studied by rheology measurements. The presence of CDEA/LG amid charged SCGLY head group shrinks the electrostatic repulsion and induces sphere-to-rod micellar transition depicting low or moderate viscosity under as-prepared neutral pH. With alteration in pH, viscosity augmented to a maximum (at pH ~5.8) followed by a viscosity decrease. This is a novel finding for mild sulfate-free SCGLY surfactant solution which otherwise is very hard to thicken. Micellar size and charge is attained by dynamic light scattering, while micellar shapes and aggregation numbers are determined by small-angle neutron scattering (SANS) measurements. Moreover, foaming behavior (foamability and stability) and mildness property (zein solubility) of SCGLY can be optimized as per the necessity in the presence of CDEA and LG. This work might prove to be an innovative approach to tune the micellar characteristics and rheology of amino acid based surfactant formulation which could be extremely beneficial for cost-effective, thickener-free, sulfate-free surfactant systems used in cleansing composition with desired viscosity.

SCPA‐Net: Self‐calibrated pyramid aggregation for image dehazing

AbstractDehazing as an important image processing field has developed for many years, there exist many excellent methods for exploring more complex networks to solve this problem. In this paper, instead of designing a complex network structure, we propose a novel dehazing network based on the consideration of enhancing feature aggregation and feature representation abilities of dehazing architecture. Specifically, we propose a self‐calibrated pyramid aggregation network (SCPA‐Net) for image dehazing, which is based on an encoder‐decoder architecture. In the encoder, we build a self‐attention block as a unit to aggregate information from a neighborhood to adapt to its content. In the decoder, we introduce a self‐calibration block to capture long‐range spatial and channel dependencies to produce more discriminative representations. Finally, to learn the scale information, the pyramid upsampling structure is applied to aggregate the multiscale self‐calibrated attentive features. Experimental results show our SCPA‐Net can achieve impressive dehazing performance.

Structural complexity of Konjac glucomannan and its derivatives governs the diversity and outputs of gut microbiota

Deacetylated Konjac Glucomannan (DKGM) and Konjac Oligo-glucomannan (KOGM) as two most widely used derivatives in food industry are structurally and physiologically distinct from Konjac glucomannan (KGM). However, the roles of their distinct structures and physicochemical properties in directing microbiota community and the following outcomes are not fully understood. This paper aims to build links between structural complexity of KGM and its derivatives and microbial metabolism. Results showed that structural alterations changed molecular chain aggregation and water binding ability, thus affected the susceptibility to enzymatic degradation, leading to the distinct microbial composition and outcomes profile. Explicitly, KOGM was distinctive in higher abundances of Catenibacterium and Megasphaera, and lacking Prevotella, which was additionally enriched by KGM and DKGM. KOGM, owned the same butyrate-dominant profile with KGM, was utilized fast. However, KGM possessed the highest fermentability. Severe deacetylation reduced fermentability and led DKGM to a propionate-dominant pattern.

Improvement of lead-zinc ore mining waste processing

Expansion of mineral reserves and resources in Russia is currently connected with larger scale commercialization of rebellious ore and mining waste, and the percentage of the latter continuously grows. Due to the complex material constitution of minerals, their similar physicochemical and processing properties, as well as because of deficient ore pre-treatment, up to 20% of valuable minerals and metals are lost with tailings, mostly with very fine particles less than 10 µm. It is of the great concern to improve processing technologies for ore and mining waste. This research aims to analyze mineral compositions of tailings after lead-zinc ore flotation, and to identify causes of lead and zinc losses with the flotation tailings. The technology tests reveal that the losses lead and zinc in the form of micron size grains of galena (PbS) and wurtzite (ZnS) are connected with their aggregation with other minerals (quartz, pyrite, magnetite, etc.). The tests with physical (radiation) treatment show dissociation ability of aggregates with subsequent separation of minerals by flotation. The presence of magnetic magnetite in flotation tailings makes it possible to implement magnetic separation to increase the contents of lead and zinc in the concentrate. The scientific novelty and practical significance of this research consists in the proved expediency of radiation treatment of minerals and mining waste toward modification of their processibilty to ensure reduction in loss of valued components with tailings and to enhance environmental safety of mining waste.

Synthesis of d‐glucitolbased Gemini amphiphilic nanotransporters

AbstractA newer class of Gemini amphiphiles was prepared using d‐glucitol as a template. C18 alkyl chains are incorporated on the template to confer hydrophobicity while monomethoxy polyethylene glycol (mPEG) moiety of varied size imparts hydrophilicity. An acetonide group mounted on glucitol moiety is used to maintain rigidity in the amphiphilic architecture and to study its impact on aggregation and transport ability. The aggregation behavior of the synthesized amphiphiles was studied through fluorescence spectroscopy, dynamic light scattering (DLS), and cryo‐transmission electron microscopy (cryo‐TEM). Their nanotransport potential was demonstrated using hydrophobic model guests like the fluorescent dye Nile red and the pharmacologically active agent curcumin. Cytotoxicity and cellular uptake studies were carried out over HeLa cancer cells to evaluate their biological applicability. The ester functionalities in the amphiphiles enable them to exhibit sensitivity towards hydrolases. Candida antarctica lipase (Novozym‐435) has been successfully utilized to facilitate the enzyme‐assisted release of the encapsulated dye.

Self-Aggregation and Denitrifying Strains Accelerate Granulation and Enhance Denitrification

A long start-up period is one of the main factors limiting the practical application of aerobic granular sludge (AGS). Bioaugmentation could be a good strategy to accelerate aerobic granulation. In this research, four denitrifying strains were isolated from mature AGS. Mycobacterium senegalense X3-1 exhibited the strongest self-aggregation ability and good denitrification ability. Ensifer adhaerens X1 showed the strongest denitrification ability but poor self-aggregation ability. Additionally, strain X3-1 demonstrated the highest extracellular polymeric substances (EPS) contents accompanied by relatively high N-acyl-homoserine lactones (AHLs) concentrations, which could illustrate its predominant aggregation ability—AHLs produced by bacteria regulate EPS secretion to accelerate cell aggregation. Strain X3-1 and X1 were chosen as inoculated bacterium to verify the effects of bioaugmentation on AGS granulation and denitrification. Granulation was achieved in the sequential batch reactors (SBRs) added strain X3-1 10 days earlier than the control group. The particle morphology and TIN removal rate of X3-1 were both superior to the latter. The introduction of strains reduced the richness and diversity of the microbial community, but the key functional bacteria, Candidatus_Competibacter, proliferates in the SBR inoculated with X3-1. Conclusively, it is suggested Mycobacterium senegalense X3-1 could be a prospective strain for enhancing AGS formation and denitrification.

Analyzing the roles of cyclic dimeric guanosine monophosphate (c-di-GMP) on the formation of autotrophic granules and autotrophic biofilm in integrated fixed-film activated sludge (IFAS) reactor

This study is the first to reveal the important roles of c-di-GMP on the formation of autotrophic granular sludge (AUGS) and autotrophic biofilm (AUB) in integrated fixed-film activated sludge (IFAS) system. The results revealed that the partial nitrification/anammox (PN/A) performance was successfully developed in the IFAS system and high nitrogen removal efficiency was obtained. Notably, it was clearly indicated that the intracellular c-di-GMP content was highly linearly correlated with the concentration of protein (PN) in tightly bound extracellular polymeric substances (TB-EPS) during AUGS formation. It was also found that the c-di-GMP content was highly linearly correlated with the PN concentration during AUB formation, and also had a good linear correlation with the polysaccharide (PS) content in TB-EPS. This proves that intracellular c-di-GMP played a vital role in regulating the TB-EPS secretion, thereby further affecting the aggregation ability of AUGS and AUB. In addition, when the c-di-GMP regulates the content of PN in TB-EPS, the secondary structure of the PN also changes significantly correspondingly, affecting the hydrophobicity of AUGS and AUB. In long-term operation, Candidatus_Kuenenia, Nitrosomonas and Flavobacterium gradually became dominant species, which were considered to favor the formation of AUGS and AUB by promoting the production of c-di-GMP and TB-EPS.

Multi-species colloidosomes by surface-modified lactic acid bacteria with enhanced aggregation properties

HypothesisSurface modification of lactic acid bacteria enhances their adsorption and aggregation at air–water interface and enables stabilization of microbubbles that spontaneously transform into water-filled colloidosomes, which can be further modified using LBL formulations. ExperimentsThe bacterial physicochemical properties were characterized using water contact angle (WCA) measurement, bacterial aggregation assay and zeta potential measurement. Cell viability was enumerated using plate-counting method. The LBL reinforcement of colloidosomes was examined by zeta potential measurement and the formed microstructure was investigated using bright-field microscopy, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Shell permeability of colloidosomes was evaluated using a dye release study. FindingsBacteria surface-modified using octenyl succinic anhydride (OSA) expressed strong adsorption and aggregation at air–water interface when producing microbubbles. Bacteria with enhanced aggregation ability formed stable shells, enabling complete removal of air and air–water interface without shell disintegration. The formed colloidosomes were studied as they were, or were further reinforced by LBL deposition using polymer or hybrid formulations. Hybrid coating involved assembly of two bacterial species producing colloidosomes with low shell porosity. The findings can be exploited to organize different living bacteria into structured materials and to encapsulate and release substances of diverse sizes and surface properties.

Effects of cholesterol on the mechanism of fengycin, a biofungicide

Fengycins are a class of antifungal lipopeptides synthesized by the bacteria Bacillus subtilis, commercially available as the primary component of the agricultural fungicide Serenade. They are toxic to fungi but far less to mammalian cells. One key difference between mammalian and fungal cell membranes is the presence of cholesterol only in the former; recent experimental work showed that the presence of cholesterol reduces fengycin-induced membrane leakage. Since our previous all-atom and coarse-grained simulations suggested that aggregation of membrane-bound fengycin is central to its ability to disrupt membranes, we hypothesized that cholesterol might reduce fengycin aggregation. Here, we test this hypothesis using coarse-grained molecular dynamics simulations, with sampling enhanced via the weighted ensemble method. The results indicate that cholesterol subtly alters the size distribution for fengycin aggregates, limits the lateral range of their membrane disordering, and reduces the ability of aggregates to bend the membrane. Taken together, these phenomena may account for cholesterol’s effects on fengycin activity.

Adhesion and Colonization of the Probiotic Lactobacillus plantarum HC-2 in the Intestine of Litopenaeus Vannamei Are Associated With Bacterial Surface Proteins.

Surface proteins are a type of proteins expressed on the surface of bacteria that play an important role in cell wall synthesis, maintenance of cell morphology, and signaling with the host. Our previous study showed that the probiotic Lactobacillus plantarum HC-2 improved the growth performance and immune response of Litopenaeus vannamei. To further investigate the probiotic mechanism, we determined the automatic aggregation ability of the bacteria and surface hydrophobicity of HC-2 after being treated with 5 M of lithium chloride (LiCl) and observed the morphology and adhesion of the bacteria to HCT116 cells. The results showed that with the removal of the HC-2 surface protein, the auto-aggregation ability and surface hydrophobicity of HC-2 decreased, and the crude mucus layer coated on the bacterial surface gradually dissociated. The adhesion rate of HC-2 to HCT116 cells decreased from 98.1 to 20.9%. Moreover, a total of 201 unique proteins were identified from the mixture of the surface proteins by mass spectrometry (MS). Several proteins are involved in transcription and translation, biosynthetic or metabolic process, cell cycle or division, cell wall synthesis, and emergency response. Meanwhile, a quantitative real-time PCR qPCR_ showed that HC-2 was mainly colonized in the midgut of shrimp, and the colonization numbers were 15 times higher than that in the foregut, while the colonization rate in the hindgut was lower. The adhesion activity measurement showed that the adhesion level of HC-2 to crude intestinal mucus of L. vannamei was higher than that of bovine serum albumin (BSA) and collagen, and the adhesion capacity of the bacterial cells decreased with the extension of LiCl-treatment time. Finally, we identified the elongation factor Tu, Type I glyceraldehyde-3-phosphate dehydrogenase, small heat shock protein, and 30S ribosomal protein from the surface proteins, which may be the adhesion proteins of HC-2 colonization in the shrimp intestine. The above results indicate that surface proteins play an important role in maintaining the cell structure stability and cell adhesion. Surface proteomics analysis contributes to describing potential protein-mediated probiotic-host interactions. The identification of some interacting proteins in this work may be beneficial to further understand the adhesion/colonization mechanism and probiotic properties of L. plantarum HC-2 in the shrimp intestine.

In vitro evaluation of probiotic properties of lactic acid bacteria isolated from the vagina of yak (Bos grunniens).

Bovine endometritis is an inflammatory disease of the uterus that occurs after parturition and can result in the destruction of uterine microecology, disruption of hormone secretion, and even infertility. Problems such as antibiotic residues, pathogen resistance, and microbiota dysbiosis caused by conventional antibiotic therapy cannot be ignored. According to the microecological balance theory, probiotics have the potential to prevent or cure endometritis in cattle. Probiotics can positively influence host physiology by regulating microecological imbalance, modulating immunity, and antagonizing pathogens. Since some probiotics contribute to host health only in their specific natural niches, lactic acid bacteria (LAB) from the vagina may have better potential to fight against vaginal and uterine infection. The yak (Bos grunniens) is an ancient and primitive livestock animal that is adapted to high altitude and harsh environments (cold, nutritional deficiencies, and hypoxia). However, to our knowledge, there have been no studies on yak vaginal LAB. Therefore, the purpose of this study was to isolate vaginal LAB from yak, evaluate and compare the probiotic potential and safety of the isolates, and help establish the probiotics library that can be used in the prevention and/or treatment of endometritis. Twenty-five vaginal swabs were collected from healthy yak and cultured in deMan, Rogosa, and Sharpe (MRS) broth. Tentative LAB strains were preliminarily determined through calcium dissolving zone and morphological identification, and the strains were then identified using 16S rRNA gene sequencing. The probiotics of the isolates were detected using cell aggregation, hydrophobicity, resistance to acid and bile salt, adhesion, and antibacterial activities. Additionally, antimicrobial susceptibility, hemolytic activity, and detection of potential virulence factors were determined in order to confirm the safety of these strains. Five isolates were identified: Leuconostoc mesenteroides, Lactobacillus plantarum, Enterococcus hirae, Lacticaseibacillus camelliae, and Lactobacillus mucosae. All isolates had certain growth resistance, aggregation ability, effective antimicrobial potency against Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium, were sensitive to most antibiotics, and could effectively adhere to bovine endometrial epithelial cells (BEECs). None of the isolates showed hemolytic activity or harbored virulence factors. Our results indicated that the five isolates have considerable potential as probiotics that can be used to prevent and/or treat bovine endometritis. We speculate that a mixture of YD6, YD9, and YD25 may yield better results, although this would require extensive experiments to verify.

Strain-dependent effectivity, and protective role against enzymes of S-layers in Lactiplantibacillus plantarum strains.

The present study investigated whether the surface layer (S-layer), which is known to have a varying effect from strain to strain on aggregation, adhesion ability, also has an effect on the resistance of bacteria to digestive enzymes, phenol, lysozymes. The effect of S-layers on the resistance against various enzymes, aggregation and adhesion abilities, and strain specificity were determined of eight Lactiplantibacillus plantarum strains. Strains were treated with 5 M lithium chloride (LiCl) to extract the S-layers, the presence of this layer in those microorganisms was demonstrated by polyacrylamide gel electrophoresis. Scanning electron microscopy was used to visualize the separation of the S-layer, which surrounds the microorganism, from the microorganism by the LiCl. The images were taken three times, once at the beginning, once 30 min later, and once at the end of this process, which took 2 h in total. The effect against enzymes varied depending on the strain, but it was determined that all the tested strains had a serious loss of viability against phenol in the absence of an S-layer. Lpb. plantarum DA100 showed a maximum decrease against gastrointestinal system enzymes after the LiCl (96.48 ± 0.03% beforeand 66.46 ± 0.01% after LiCl). Lpb. plantarum DA255 showed a significant decrease against lysozyme (99.11 ± 0.00% before and 62.80 ± 0.0% after LiCl). Removal of the S-layer greatly affected the adhesion ability of some strains, while for others there was hardly any change. The results showed that the role of the S-layer may be strain-specific, the rate of effect can vary. The primary function of S-layer proteins is thought to contribute to the adhesion ability of bacteria. There are limited studies that have reported the protective property of this layer against various enzymes, however, our results showed that S-layer could be one of the resistance strategies developed by bacteria against enzymes.

Enhanced adsorption performance of subordinate magnesium sites in pinhole magnesium oxide nanosheets with rich oxygen vacancies

Phosphorus recovery from wastewater is important for protecting the aquatic environment and achieving sustainable development. However, as a typical phosphorus adsorbent, nanoscale magnesium oxide (MgO) exhibits aggregation and limited adsorption ability. Herein, melamine foam (MF) was selected as a self-sacrifice template to prepare an oxygen-vacancy-rich MgO/MF phosphate adsorbent with high dispersion and a multistage pore structure. Density-functional theory calculations reveal that the phosphate preferentially adsorbed on the hollow sites rather than top sites of MgO when there were oxygen vacancies, which improved the intrinsic adsorption ability of MgO/MF. The MgO/MF adsorbent exhibited excellent phosphorus removal from water within a wide pH range of 2–12; the maximum adsorption capacity of phosphate was as high as 1226 ​mg/g. The adsorption capacity of the MgO/MF adsorbent after phosphate adsorption was reactivated to ca. 100%. After six adsorption cycles, MgO/MF with a high phosphate content of 117.5 ​mg ​P/g is a potential high-quality fertilizer. This work provides a promising strategy for constructing an efficient adsorbent for wastewater treatment and resource recovery.

Manipulating molecular aggregation and crystalline behavior of A‐DA'D‐A type acceptors by side chain engineering in organic solar cells

AbstractAlkyl chains engineering plays an important role in photovoltaic materials for organic solar cells. Herein, three A‐DA'D‐A (acceptor–donor–acceptor'–donor–acceptor) type acceptors named Y6, Y6‐C4, and Y6‐C5 with different branching position on the pyrrole motif are discussed and the relationship between molecular aggregation, crystalline, and device performance are systematically investigated. The distance between the branching position and the main backbone affects their optical absorption and energy levels. Y6‐C4 and Y6‐C5 with the branching position at the fourth and fifth carbon of the alkyl chain show blue‐shifted absorption and increased electrochemical bandgaps, compared with Y6 with the branching position at the second carbon of the alkyl side chain. In addition, this distance influences the molecular aggregation and crystalline behavior of the donor/acceptor blends. Compared with Y6‐C4, Y6‐C5 possesses a stronger crystalline and aggregate ability in the blends with a lower non‐radiative energy loss, which results in a higher open circuit voltage (Voc) of 0.88 V. Finally, Y6‐C5‐based binary device achieved a high power conversion efficiency up to 16.73% with afill factor (FF) of 0.78. These results demonstrate that the side chain engineering is an effective strategy for tuning the molecular aggregation and crystalline to improve photovoltaic performance of the A‐DA'D‐A type acceptors.