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We prove that the stable image of an endomorphism of a virtually free group is computable. For an endomorphism φ , an element x ∈ G and a subset K ⊆ G , we say that the φ -order of g relative to K , φ -ord K (g) , is the smallest nonnegative integer k such that g φ k ∈ K. We prove that the set of orders, which we call φ -spectrum, is computable in two extreme cases: when K is a finite subset and when K is a recognizable subset. The finite case is proved for virtually free groups and the recognizable case for finitely presented groups. The case of finitely generated virtually abelian groups and some variations of the problem are also discussed. [ABSTRACT FROM AUTHOR]

A graph is said to be uniquely hamiltonian if it has a unique hamiltonian cycle. For a natural extension of this concept to infinite graphs, we find all uniquely hamiltonian vertex‐transitive graphs with finitely many ends, and also discuss some examples with infinitely many ends. In particular, we show each nonabelian free group Fn has a Cayley graph of degree 2n+2 that has a unique hamiltonian circle. (A weaker statement had been conjectured by Georgakopoulos.) Furthermore, we prove that these Cayley graphs of Fn are outerplanar. [ABSTRACT FROM AUTHOR]

Schur rings are subrings of the group ring of the group G afforded by a partition of G into finite sets. In this paper, Schur rings over a free abelian group of rank two are classified under the assumption that one of the direct factors is a union of some basic sets. There are eight different types, and all but one type of which are traditional. [ABSTRACT FROM AUTHOR]

[Display omitted] • Different functional groups modified UiO-66-X nanopaticles were synthesized by solvothermal method. • UiO-66-X nanoparticles have superior adsorption performance toward iodine. • The sorption properties are dependent on the modified functional groups in the UiO-66-X skeleton. Radioactive iodine waste from the nuclear industry poses a critical threat to human health, and its effective capture has become an important research topic. In this study, modified UiO-66-X adsorbents (where X is ATA, BTA, or STA) were used to investigate the effects of the free functional groups in the UiO-66 skeleton on iodine capture in the vapor and solution states. The adsorption behavior revealed that the capture efficiency of UiO-66-ATA was substantially higher than that of UiO-66-BTA and UiO-66-STA because the electron-donating amino groups could enhance the I − I···π halogen bond interactions compared with the electron-withdrawing carboxyl and sulfonic acid groups. In addition, the pore volume of UiO-66-ATA was significantly higher than those of UiO-66-BTA and UiO-66-STA. In particular, the removal uptakes of UiO-66-ATA were 1108.1 mg/g (vapor phase) and 3601.9 mg/g (aqueous solution). This study is the first to investigate the effects of functional groups on the adsorption uptake of UiO-66 toward iodine. This efficient functional group modification strategy holds significant promise for the development of novel metal–organic framework adsorbents. [ABSTRACT FROM AUTHOR]

The structure, properties, as well as the oil absorption characteristics of wheat flour (WF) treated with varying concentrations of transglutaminase (TG) (0 U/g ∼ 50 U/g) were characterized. The content of free amino groups in WF modified by TG (TG-WF) decreased and protein aggregated. The isopeptide bonds and disulfide bonds played important roles in protein crosslinking. The thermal stability, the peak viscosity after gelatinization and protein secondary structure stability of TG-WF were improved. In addition, the oil absorption and surface oil content of TG-WF after frying were reduced. TG enhanced the protein-protein interactions in WF, so that protein played barrier roles in the process of high-temperature frying, protecting the starch particles covered by them from the infiltration of oil, thus reducing the oil absorption of TG-WF during frying. Among them, the oil content of TG-WF-30 U/g after frying was the lowest, which decreased by 10.73 % compared with the control group. [Display omitted] • TG can catalyze protein cross-linking to form network structure. • TG changed the content of inter-molecular forces and secondary structures of protein. • The modification of WF by TG occurred in non-gelatinizing and non-dough system. • The thermal stability and peak viscosity of TG-WF were improved. • The oil content of WF modified by TG were decreased after frying. [ABSTRACT FROM AUTHOR]

• In the literature, no 6-aminocoumarin (6-amino-COM) with a free amino group that has been biomedically investigated. • Nine novel 6-amino-COMs were synthesized in a one-pot reaction from acetaminophen with confirmed structures. • The anticancer and antimicrobial activities were studied against six cancer-derived cells and ten pathogenic microbes. • The biocompatibility was also evaluated for three normal cell types and three natural body bacteriomers. • The results revealed that our 6-amino-COMs have potent and wide-ranged anticancer and antimicrobial activities. • The multiple biomedical activities were coupled with high biocompatibility, projecting our compounds as valuable scaffolds. Among the most health-influencing threats, microbial infections and cancer have attracted a mounting interest in the medical field. To face these threats, research is directed to improve the currently-in-use medications and explore now bioactive agents. Given the latter approach, this work involves the synthesis of nine 6-aminocoumarins, coded ACM1 - ACM9 , starting from acetaminophen. The structural frameworks of the synthesized compounds were established by studying their charts abstracted from FTIR, 1HNMR , 13CNMR , and HRMS. The performed biomedical study was branched into two parts; the first included testing the antimicrobial characteristics of the synthesized compounds against ten pathogenic microbes using a broth-diluting method. These pathogens included four aerobic as well as four anaerobic bacterial strains, and two fungiomers. On the other hand, the MTT-probing method was employed to evaluate the anticancer properties of the synthesized compounds against six cancer-derived cellular types. The second biomedical study part involved the use of the same practical methods to explore the synthesized compounds' biocompatibility towards normal three cell types and three bacterial strains. Compared to the references used, the results of the first study revealed that the synthesized coumarins demonstrated potent and broad-ranged antimicrobial properties. Also, the best activity against pathogenic aerobes and fungiomers was attributed to ACM9 , with MIC values of 2 µg/ml and 1.15–1.30 µg/ml, respectively. The ACM3 exhibited the best anti-anaerobic bacterial activity, with MIC values ranging from 6 to 9 µg/ml. Given the anticancer activity, our coumarins showed encouraging outcomes, with ACM6 being the best, affording IC 50 values between 22.34 and 50.29 µg/ml. Regarding the second study, the synthesized coumarins demonstrated high biocompatibility levels toward normal cells (IC 50 values ranged from 224.59 to 248.19 µg/ml) and bacterial strains (MIC values ranged from 308 to 330 µg/ml) under investigation. From these interesting findings, the author concluded that the synthesized coumarins provided a privileged scaffold with multiple biomedical activities that varies based on the type of the substitution on the aromatic ring. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work we begin the study of n -valued maps on the Klein bottle, denoted by K , where we focus on the split ones. We provide an explicit description of P n (K) (the n -th pure braid group of K) as an iterated semi-direct product of the form F n ⋊ θ n − 1 (⋯ ⋊ (F 2 ⋊ θ 1 π 1 (K))) , where the F i ′ s are free groups on i letters. Given a split n -valued map Φ = { f 1 , ... , f n } its pointed homotopy class is determined by a pair of braids in P n (K). We also provide a formula for N (Φ) , the Nielsen number of Φ, which is completely determined by two braids, which in turn also determine the homotopy classes of the functions f i ′ s. If Φ = { f 1 , f 2 } is a 2-valued map with N (Φ) = 0 , we show that there exists at least one 2-valued map Φ ′ = { f 1 ′ , f 2 ′ } , such that Φ ′ is fixed point free and for i = 1 , 2 it holds that [ f i ] = [ f i ′ ] , where [ ] denotes a pointed homotopy class of maps. Finally, we display an infinite family of pointed homotopy classes in [ K , F 2 (K) ] , such that N (ϕ) = 0 , for any ϕ in the family. Furthermore, the map from [ K , F 2 (K) ] to [ K , K × K ] , induced by the inclusion F 2 (K) → K × K , takes this family to one single element in [ K , K × K ]. We do not know if these 2-valued maps of the family can be deformed to fixed point free maps. [ABSTRACT FROM AUTHOR]

Two isoreticular 3D MOFs exhibiting a large NH 3 uptake (11 ∼ 14 mmol/g at 1 bar) were constructed and structurally analyzed by the in-situ FT-IR spectroscopy and DFT calculations, providing insight into the adsorption process. [Display omitted] • Two interpenetrated amino-functionalized MOFs were structurally determined and activated examined by IR. • The maximum NH 3 uptakes of Co-2AN-MOF and Cd-2AN-MOF are 11.7 and 13.8 mmol/g at 1 bar respectively. • In-situ infrared spectroscopy and DFT calculation revealed the adsorption sites and processes. Two isostructural, three-dimensional, interpenetrated amino-functionalized Metal-Organic Frameworks (Co-2AIN-MOF and Cd-2AIN-MOF) based on 2-aminoisonicotinic acid (2AIN) were synthesized, structurally characterized and determined. Based on the PXRD analysis, the solvent exchange hardly changed their framework structure, and the samples fully activated by methanol can be achieved and examined by infrared spectroscopy. Due to the presence of the carbonyl group and free amino groups in the pore of the framework, the NH 3 uptakes of Co-2AIN-MOF and Cd-2AIN-MOF are 11.70 and 13.81 mmol/g and at 1 bar, respectively. In-situ Infrared spectroscopy and DFT calculations revealed the different adsorption sites and processes between Co-2AIN-MOF and Cd-2AIN-MOF. [ABSTRACT FROM AUTHOR]

Developing of bio-based wood adhesives is an inevitable common topic in the development at top speed of wood industry. Herein, a bio-based tannin wood adhesive, named as tannin-based non-isocyanate polyurethane-urea (TNIPU-U), was designed which showing a ultra-strong adhesion and water resistance performance by two-step approach. A plausible mechanism was proposed, which implied that urea acted as the crosslinker to connect with derived intermediates containing free amino groups rooted from the reaction of tannin, dimethyl carbonate (DMC), and HMDA, to introduce urea linkages in traditional TNIPU. Furthermore, addition of urea to act as a trapping agent to capture excessive free HMDA in TNIPU adhesive, promoting additional polyurea formation, leading to avoidance of its emission during the hot-pressing process. This will convert the imperfection of TNIPU to a superiority by a eco-friendly strategy. The complicated cross-linked networks will be obtained that are rich in physical entanglement, covalent bonds, and hydrogen bonds. Compared with the TNIPU, the shear strength of TNIPU-U adhesive, after soaked in hot water and boiling water for 3 h, exhibited increase by 17.88 % and 34 %, respectively, indicating the potential for use under harsher conditions. Moreover, the TNIPU-U adhesive exhibits an excellent bonding performance (1.93 MPa) that greatly exceeds the China National Standard (GB/T 9846–2015, ≥ 0.7 MPa) requirement for exterior-grade plywood type I. It is comparable to commercial phenol-formaldehyde resin on the aspect of water tolerance. It can be applied to particleboard preparation and bamboo bonding as well, showing a well-adopted feature. This study provides an efficient, low-cost, and sustainable strategy for high performance bio-based wood adhesives. [Display omitted] • A novel tannin-based non-isocyanate polyurethane urea adhesive has been prepared. • Urea served as a crosslinker to capture free HMDA that averting its volatilization. • The complicated cross-linked network was built that has given an enhanced properties. • TNIPU-U adhesive met the application requirement for exterior-grade plywood type I. • It satisfied the application for particleboard preparation and bamboo bonding. [ABSTRACT FROM AUTHOR]

In 2022, the International Society of Exposure Science (ISES) International Human Biomonitoring (i-HBM) Working Group launched a free, online repository of biomonitoring guidance values referred to as the Human Biomonitoring Health-Based Guidance Value (HB2GV) Dashboard. The goal of the Dashboard is to assist global human biomonitoring data users (e.g., risk assessors, risk managers) and human biomonitoring programs with a readily available compilation of guidance values for the general population. The Dashboard contains approximately 600 HB2GVs for over 150 chemicals or their metabolites. Although there are many different types of HB2GVs, most are Biomonitoring Equivalents (BEs), Human Biomonitoring (HBM-I and HBM-II) values, or Human Biomonitoring Guidance Values (HBM-GVs). For users new to human biomonitoring, understanding how the different types of HB2GVs are derived and how to interpret those values in the context of human biomonitoring data can be difficult. Therefore, there is a need to inform users of the differences among available guidance values and to help users identify the HB2GV that could be most suitable for their purposes. Here, we summarize the derivation of HB2GVs for a case study chemical, di-(2-ethylhexyl) phthalate (DEHP). We selected DEHP as there are 36 unique HB2GVs available from three of the most common types of guidance values (i.e., BE, HBM-I value, HBM-GV). We also compare the available HB2GVs with a focus on the differences among their derivation methods, relative quality and confidence, and interpretation. This case study provides guidance on the use of existing HB2GVs for health-based interpretation of human biomonitoring data that may be applied to other chemicals. As with any other type of guidance or regulatory value (e.g., RfDs, MRLs), thoughtful selection and use are strongly encouraged. Appropriately interpreting HBM data with the aid of guidance values can result in improved decision making which, ultimately, could lead to better protection of public health. [ABSTRACT FROM AUTHOR]

Polybenzimidazole-based ion-solvating membranes (ISMs) are regarded as a promising contender for alkaline water electrolysis separators due to their mechanical stability, excellent thermal stability, and gas tightness. However, the trade-off between hydroxide conductivity and alkaline stability restricts the application. In this paper, poly(2, 2'-(4, 4′-1, 1′-binaphthyl)-5, 5′-benzimidazole) (BN-PBI) was synthesized from a molecular design perspective, followed by the in-situ scrapping of a BN-PBI membrane and subsequent immersion in a KOH solution to yield a KOH-doped ion-solvating BN-PBI gel membrane. m -PBI and N-PBI gel membranes were also fabricated under the same conditions for comparison. The incorporation of the bulky and rigid binaphthyl groups increased the free volume of the polymer, which effectively regulated the absorption of alkali and water. Consequently, the BN-PBI gel membrane exhibited an impressive hydroxide conductivity of up to 274.48 mS cm−1 in a 6 M KOH solution at 80 °C. Moreover, the ionic conductivity retention was still above 62.43 % after a 3400 h ex-situ alkaline stability test. During the AWE test, the cell with the BN-PBI gel membrane achieved the highest current density of 750 mA cm−2 at a voltage of 2 V and 80 °C. Additionally, under a constant current density of 500 mA cm−2 in a 6 M KOH solution at 80 °C, the cell demonstrated stable performance over 180 h with a voltage fluctuation of only 39 μV. Therefore, this work proposes a new perspective on addressing the trade-off between hydroxide conductivity and alkaline stability, facilitating the development of new separator materials for alkaline water electrolysis. [Display omitted] • Binaphthyl-derived polybenzimidazole ion-solvating gel membrane with OH− conductivity of up to 274.48 mS cm−1 was fabricated in-situ. • The BN-PBI gel membrane exhibited an excellent alkaline water electrolysis performance and extended durability. • A new approach has been proposed to address the trade-off between hydroxide conductivity and alkaline stability in ion-solvating membranes. [ABSTRACT FROM AUTHOR]

In order to solve the problem of poor performance of giant squid gel, this study proposed a method to induce the aggregation of giant squid protein molecules by exogenous additives to improve its gel performance. The particle size, zeta potential, free sulfhydryl group, carbonyl group and hydrophobic index of protein solution were characterized by laser light scattering, fluorescence spectrum and ultraviolet spectrum, and the effect of egg white protein (EWP) on myofibrillar protein (MP) aggregation was analyzed. In the presence of EWP, the density and R g /R h value of protein particles decreased significantly after mixing for 600 min, indicating that the interaction between MP and EWP protein could be enhanced by embedding appropriate amount of EWP in the middle of MP protein. With the increase of the proportion of egg white protein, the blue shift of the maximum absorption wavelength of endogenous fluorescence in the mixed protein solution decreased. In the range of 25–65 °C, the change rates of surface charge, free sulfhydryl group, carbonyl group and surface hydrophobicity decreased, which proved that EWP inhibited the self-aggregation rate of MP molecules during the heating process, and induced its gel by interspersing between MP molecules to improve the formation of three-dimensional network during protein thermal gel process. Finally, the addition of EWP improved the gel properties of giant squid surimi. This study offered new direction for improving gel properties and promotes the development and application of giant squid. [Display omitted] • Egg white protein (EWP) can improve the strength of giant squid surimi gel. • EWP inhibits the aggregation rate of myofibrillar protein molecules during heating. • EWP affects the formation of three-dimensional network structure of surimi protein. • There is an obvious interaction between EWP and giant squid myofibrillar protein. [ABSTRACT FROM AUTHOR]

Citrus pectins (CP) are the most common types of commercial pectins, and their gelling properties are of interest in many industrial applications. However, the dynamic changes in the chemical structures and gelling properties of pectins during citrus maturation and storage are poorly understood. This study compared pectins from citrus fruit in terms of different maturity (M1: green citrus; M2: green-yellow citrus; M3: light orange citrus; FM: full maturity citrus) and storage times (S1: 10-day; S2: 20-day; S3: 30-day). All pectin were high-methoxylated polymers, with high content of HG and RG-I domain (about 95.0 mol%). With increasing citrus maturity and storage time, HG content (from 69.0 mol% to 51.9 mol%), the molecular weight and methyl-esterification of pectins continuously decreased, while the RG-I content (from 26.4 mol% to 42.5 mol%) and compact spatial conformation significantly increased. Polygalacturonase, methylesterase, α-arabinofuranosidase, β-galactosidase, and cellulase, induced dynamic variations in the structural characteristics of pectins. The decreases in HG content and the lower molecular weight reduced hydrogen bonding and the hydrophobic interactions, thus weakening the gelling properties. The relatively high RG-I content, the additional hydrogen bonds generated by the free carboxyl groups, and the compact conformation shortened the distances between pectin chains and increased chain entanglement, thereby ensuring that the gel network was stable. Consequently, CP S3 gel exhibited the greatest strength (hardness: 977.0 g, A α : 642.9 Pa sα) and satisfactory extrusion recovery ability (springiness: 95.5%). These results can guide the selection of raw materials that will yield pectins with specific structural characteristics and superior gelling properties. [Display omitted] • The chemical structure and gelling properties of citrus pectin changed dynamically. • Citrus maturity reduced HG ratio and DM of pectins, but increased their compactness. • Endogenous enzymes in citrus fruit accounted for the structural variations of pectin. • Pectins in citrus fruit stored for 30 days had the best gel strength and good stability. • Alterations in the chemical structures of pectins regulated their gelling properties. [ABSTRACT FROM AUTHOR]