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Helicobacter pylori (H. pylori) is a globally widespread bacterial infection. Early diagnosis of this infection is vital for public and individual health. Prevalent diagnosis methods like the isotope 13C or 14C labelled urea breath test (UBT) are not convenient and may do harm to the human body. The use of cross-response gas sensor arrays (GSAs) is an alternative way for label-free detection of metabolite changes in exhaled breath (EB). However, conventional GSAs are complex to prepare, lack reliability, and fail to discriminate subtle changes in EB due to the use of numerous sensing elements and single dimensional signal. This work presents a dual-element multimodal GSA empowered with multimodal sensing signals including conductance (G), capacitance (C), and dissipation factor (DF) to improve the ability for gas recognition and H. pylori-infection diagnosis. Sensitized by poly(diallyldimethylammonium chloride) (PDDA) and the metal–organic framework material NH2-UiO66, the dual-element graphene oxide (GO)-composite GSAs exhibited a high specific surface area and abundant adsorption sites, resulting in high sensitivity, repeatability, and fast response/recovery speed in all three signals. The multimodal sensing signals with rich sensing features allowed the GSA to detect various physicochemical properties of gas analytes, such as charge transfer and polarization ability, enhancing the sensing capabilities for gas discrimination. The dual-element GSA could differentiate different typical standard gases and non-dehumidified EB samples, demonstrating the advantages in EB analysis. In a case–control clinical study on 52 clinical EB samples, the diagnosis model based on the multimodal GSA achieved an accuracy of 94.1%, a sensitivity of 100%, and a specificity of 90.9% for diagnosing H. pylori infection, offering a promising strategy for developing an accurate, non-invasive and label-free method for disease diagnosis. [ABSTRACT FROM AUTHOR]

Nanocellulose is not only a renewable material but also brings functions that are opening new technological opportunities. Here we discuss a special subset of this material, in its fibrillated form, which is produced by aerobic microorganisms, namely, bacterial nanocellulose (BNC). BNC offers distinct advantages over plant-derived counterparts, including high purity and high degree of polymerization as well as crystallinity, strength, and water-holding capacity, among others. More remarkably, beyond classical fermentative protocols, it is possible to grow BNC on non-planar interfaces, opening new possibilities in the assembly of advanced bottom-up structures. In this review, we discuss the recent advances in the area of BNC-based biofabrication of three-dimensional (3D) designs by following solid- and soft-material templating. These methods are shown as suitable platforms to achieve bioadaptive constructs comprising highly interlocked biofilms that can be tailored with precise control over nanoscale morphological features. BNC-based biofabrication opens applications that are not possible by using traditional manufacturing routes, including direct ink writing of hydrogels. This review emphasizes the critical contributions of microbiology, colloid and surface science, as well as additive manufacturing in achieving bioadaptive designs from living matter. The future impact of BNC biofabrication is expected to take advantage of material and energy integration, residue utilization, circularity and social latitudes. Leveraging existing infrastructure, the scaleup of biofabrication routes will contribute to a new generation of advanced materials rooted in exciting synergies that combine biology, chemistry, engineering and material sciences. [ABSTRACT FROM AUTHOR]

Confined catalysis between a two-dimensional (2D) cover and metal surfaces has provided a unique environment with enhanced activity compared to uncovered metal surfaces. Within this 2D confinement, weakened adsorption and lowered activation energies were observed using surface science experiments and density functional theory (DFT) calculations. Computationally, the role of electronic and mechanical factors responsible for the improved activity was deduced only from static DFT calculations. This demands a detailed investigation on the dynamics of reactions under 2D confinement, including temperature effects. In this work, we study CO oxidation on a 2D graphene covered Pt(111) surface at 90 and 593 K using DFT-based ab initio molecular dynamics simulations starting from the transition state configuration. We show that CO oxidation in the presence of a graphene cover is substantially enhanced (2.3 times) at 90 K. Our findings suggest that 2D confined spaces can be used to enhance the activity of chemical reactions, especially at low temperatures. [ABSTRACT FROM AUTHOR]

A Ni-based pyrazolate MOF (NiBDP) is studied for SO2 adsorption under static conditions, demonstrating a high SO2 uptake of 8.48 mmol g-1 at 298 K and 1 bar while maintaining a high chemical stability. The influence of Ni(II) coordinatively unsaturated metal sites and coordinated water on the SO2 adsorption performance of this MOF is investigated by using a combination of experimental techniques, including FTIR and in situ DRIFTS measurements, along with Density Functional Theory calculations. The porefilling of the SO2 adsorbates within the material, at the molecular level, is further unravelled through grand Canonical Monte Carlo simulations employing a newly DFT-derived accurate set of force field parameters. [ABSTRACT FROM AUTHOR]

Copyright of Revista Tecnología, Ciencia & Educación is the property of Centro de Estudios Financieros SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background Misconceptions should be detected early in dental students’ training to improve their clinical performance. Accordingly, this study aimed to assess undergraduate dental students’ knowledge and performance of master gutta-percha (GP) cone selection and fitting during clinical endodontic courses at the College of Dentistry, King Saud University. Methods Ninety-nine undergraduate dental students completed an online survey about their knowledge of master GP cone selection. Forty-five of these students were observed by faculty members in clinical endodontic courses while they fitted master GP cones during root canal treatments. The observers recorded the details of each student’s cone-fitting techniques. The data were analysed using t-tests, one-way analysis of variance, and chi-square tests (p<0.05). Inter- and intra-observer reliability were tested using Fliess’ Kappa. Results Survey All participants had good knowledge of over-extended cone management, while 80.8% knew how to properly manage a short cone. The proper flaring assessment method was selected by 86.9% of the female and 34.2% of the male students, and this difference was statistically significant (p=0.0001). Observation The students labelled the working length on the master GP cone with an indentation in 64.4% of the cases and by bending the cone 35.6% of the time. Of all students, 84.4% encountered an apical stop, and this rate correlated significantly with the length of the cone on the master apical cone radiograph (p=0.001). Improper shaping of the canal was the most common cause of ill-fitting cones (83.3%), while 16.7% of the students chose the wrong cone size. The final obturation length was adequate in 80% of the cases; 57.8% of the students were helped by instructors. Conclusions Most students had the basic knowledge required to solve problems related to the selection of master GP cones. However, in the clinical setting, more than half of the students required the assistance of an instructor to adjust their cone’s fit. The presence of an apical stop had the most significant effect on the length of the fitted master GP cone on radiography. The most common cause of ill-fitting master cones was improper shaping of the canal. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Numerous research papers on biosorption have been published in the past four decades. This paper reviews and compares heavy metal uptake capacities of various biological and non-biological materials. Adsorption mechanisms and processes of heavy metal ions (HMIs) onto biomasses are summarised and discussed, respectively. In general, all types of adsorbents exhibit certain uptake capacities for HMIs, but the capacity values for different types of biomasses and non-biological materials vary significantly. For HMIs, the reported values for bacterial biomasses typically range from 0.06 mmol·g−1 to 2.84 mmol·g−1; for fungi and yeasts, 0.03 mmol·g−1 to 2.44 mmol·g−1; for fresh water algae, 0.02 mmol·g−1 to 3.15 mmol·g−1; for marine algae, 0.23 mmol·g−1 to 3.77 mmol·g−1; for other biological materials/derivatives, 0.01 mmol·g−1 to 1.78 mmol·g−1 and for non-biological materials, 0.003 mmol·g−1 to 2.40 mmol·g−1. Thereinto, a few macroalgal species exhibit much higher adsorption capacities for HMIs relative to other types of adsorbents. Statistical analysis of heavy metal uptake capacities of various biological and non-biological materials indicates that marine algae are most suitable for the development of industrial biosorbents for the remediation of diluted HMIs-bearing effluents. Biosorption mechanisms of HMIs by biomasses include physical adsorption, ion exchange, electrostatic interaction, surface complexation and inorganic microprecipitation. the physicochemical properties of biosorbents and HMIs as well as external adsorption conditions significantly influence the adsorption process of HMIs onto biomasses. It could be concluded from numerous previous studies that pseudo-first-order and pseudo-second-order models are the most commonly utilised to characterise adsorption process. Up to date biosorption of HMIs remains largely in the laboratory stage. Combining microscopic mechanisms with macroscopic models may be one of the future research directions for removal of HMIs by biomasses. [ABSTRACT FROM AUTHOR]

Cleistes rosea and 10 other taxa comprise a complex widely distributed in various open vegetation types from eastern South America to Panama. The taxonomic identity of most of these taxa is unclear and their relationships with C. rosea have never been satisfactorily discussed or tested. Here, we employ molecular phylogenetics, morphometrics and morphological, ecological and geographic distribution data to investigate the relationships and taxonomy of Cleistes rosea and related species. Our results confirm that Cleistes rosea and Cleistes castaneoides are sister species and although highly similar in general floral morphology, they differ in vegetative characters, distribution, habitat, floral scent, and lip characters. Both species show local variations regarding floral characters, particularly the flower colour, and such differences were used here to delimit infraspecific taxa within the C. rosea/C. castaneoides clade. While C. rosea var. guianensis var. nov. is restricted to French Guiana, and C. rosea var. buenaventurae stat. & comb. nov. is restricted to low altitudes on the western side of the Cordillera Occidental in the Chocó region of Colombia, C. castaneoides var. castaneoides and C. castaneoides var. augusta comb. nov. are sympatric throughout their distribution. Cleistes abdita, formerly known as C. rosea f. pallida, is similar to C. castaneoides but distinguished by the smaller flowers and restricted distribution to Amazonian savannas. Cleistes rosea is distributed throughout the north of the Andes and northern South America. In turn, C. castaneoides occurs mainly in South-eastern and Central-western Brazil. Still, the distribution of these three species overlaps in the Guiana Shield, where the differentiation between them is less evident. Our results provide evidence of the plasticity of the floral morphology of Cleistes, especially the lip, and highlight that hitherto neglected characters, such as vegetative morphology, habitat, and floral scent, are particularly informative for the characterization of species and taxonomy of the genus. [ABSTRACT FROM AUTHOR]

SO2 and NO2 capture and conversion have been investigated via density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulations using a novel hydrogen-bonded 3D metal--organic framework (MOF) containing a Zn(II) centre and a partially fluorinated (polar -CF3) long-chain dicarboxylate ligand with a melamine (basic -NH2) co-ligand. Initially, computational single-component isotherms have been determined for SO2 and NO2 gases. These simulations have shown exothermic adsorption enthalpies of ~36.4 and ~28.6 kJ mol-1 for SO2 and NO2, respectively. They have also indicated that SO2 has a high affinity for polar -CF3 and basic-NH2 binding sites of the ligand in the framework pore walls. The lower adsorption capacity of NO2 compared with SO2 is due to weaker electrostatic interactions with the framework. Furthermore, MOF adsorbent selectivity for removing trace amounts of SO2 and NO2 in flue gases has been estimated through the co-adsorption of ternary gas mixtures (SO2/ CO2/N2 and NO2/CO2/N2). Together with DFT, the climbing image nudged elastic band (CI-NEB) method has been used for investigating the plausible mechanisms for HbMOF1 catalyzed cycloadditions of SO2 and NO2 with epoxides leading to the formation of cyclic sulphites and nitrates, respectively. [ABSTRACT FROM AUTHOR]

Background: Apical periodontitis (AP) is an inflammatory disease of the apical periodontium as sequelae of pulp death. It is managed by disinfection and filling of the root canal space. Objectives: The aim of this systematic review was to investigate whether obturation techniques and materials used for root canal filling led to the management of AP. Methods: A systematic review protocol was written following the preferred reporting items for systematic reviews and meta‐analyses (PRISMA) checklist and registered on the international prospective register of systematic reviews (PROSPERO; CRD42021260275) including two populations, interventions, comparisons, outcomes and time (PICOT) for the research questions querying the effectiveness of obturation techniques (PICOT 1) and materials (PICOT 2) for the management of AP. Electronic searches were conducted on PubMed, ScienceDirect, Scopus and Embase search engines. Searches on International Endodontic Journal, Journal of Endodontics, Clinical Oral Investigations, Journal of Dental Research and Journal of Dentistry websites were also conducted, until May 2021. Both primary (tooth survival) and secondary outcomes were evaluated. The risk of bias was assessed by Cochrane RoB2 for the randomized and ROBINS‐I for the nonrandomized trials. Results: The search strategy identified 1652 studies, with 1600 excluded on the title and abstract screening, leaving 52 studies for full‐text screening. In total, 10 studies met the inclusion criteria. The obturation technique and materials used did not affect the outcome of AP. Vertical compaction resulted in faster resolution of periapical lesions. The oral health‐related quality of life of patients treated with lateral condensation exhibited poorer outcomes compared with single matched cone after 6 months of recall. Discussion: The inclusion and exclusion criteria used for this systematic review enabled the capture of all the literature available on the effect of obturation techniques and materials on the outcome of AP. The data were heterogenous, and a number of articles investigating obturation techniques had no information on the materials and techniques used as they looked at the quality of fill. Conclusions: Included studies did not find any difference between different procedures (PICOT 1) and materials (PICOT 2). The risk of bias was high, thus the findings should be interpreted with caution. Registration: PROSPERO registration number: CRD42021260275. [ABSTRACT FROM AUTHOR]

This study investigates the recycling of polyamide 6 (PA 6) wastes to produce nonwoven fabrics based on nanofibers (PA‐NWNF) to promote sustainable textile solid waste management and generate a novel material with exceptional properties. PA‐NWNF characteristics can be controlled by adjusting the electrospinning parameters. A comprehensive characterization will be performed using various analytical techniques, such as scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and dynamic mechanical analysis (DMA), to evaluate the unique properties as a function of the electrospinning parameters. According to the SEM results, concentrations of 21% are suitable to produce nanofiber with a well‐defined morphology, provided that the applied voltage is maintained at 20 kV and the collecting distance is above 10 cm, irrespective of the flow rate in the established protocol. XRD and FTIR analysis indicate a gradual decrease in the α‐phase and a simultaneous increase in the γ‐phase as the solution concentration increases. Moreover, low applied voltage favored β‐form crystallization over γ and α‐forms predominant at the higher voltage. DMA and BET data reveal that the elongated droplets formed at lower concentration exhibit a low storage modulus, high damping factor, highest surface area, and smallest pore diameters. [ABSTRACT FROM AUTHOR]

Developing robust multifunctional metal–organic frameworks (MOFs) is the key to advancing the further deployment of MOFs into relevant applications. Since the first report of MFM-300(Sc) (MFM = Manchester Framework Material, formerly known as NOTT-400), the development of applications of this robust microporous MOF has only grown. In this review, a summary of the applications of MFM-300(Sc), as well as some emerging advanced applications, have been discussed. The adsorption properties of MFM-300(Sc) are presented systematically. Particularly, this contribution is focused on acid and corrosive gas adsorption. In addition, recent applications for catalysis based on the outstanding hemilabile Sc–O bond character are highlighted. Finally, some new research areas are introduced, such as host–guest chemistry and biomedical applications. This highlight aims to showcase the recent advances and the potential for developing new applications of this promising material. [ABSTRACT FROM AUTHOR]

Different oxidative pathways of sulfur dioxide promoted by ZnO(NO3)2−, Zn(NO3)2− and Zn(NO2)(NO3)− are revealed by a joint investigation by mass spectrometry and theoretical calculations. The reactions are triggered by [Zn2+‐O−⋅]+ or by the low‐valence Zn+ through oxygen ion transfer or electron transfer to SO2, respectively. The NOx− ligands intervene in the oxidation only when sulfur dioxide is converted to SO3− or SO2−, leading to the formation of zinc sulfate and zinc sulfite coordinated to nitrate or nitrite anions. Kinetic analyses show that the reactions are fast and efficient, and theory discloses the elementary steps, namely oxygen ion transfer, oxygen atom transfer and electron transfer, occurring through similar energy landscapes for the three reactive anions. [ABSTRACT FROM AUTHOR]

Copyright of Entorno Geográfico is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Crítica y Resistencias: Revista de conflictos sociales latinoamericanos is the property of Fundacion El llano - Centro de Estudios Politicos y Sociales de America Latina (CEPSAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Photosynthesis is susceptible in response to nitrogen (N) deficiency. However, the acclimation of shade-tolerant and high-N sensitive species to N deficiency is unclear. Leaf morpho-physiological traits, photosynthetic performance related parameters were examined in a shade-tolerant and high-N sensitive species P. notoginseng grown under different N levels. Lower N content and Chl content were recorded in the N0-grown P. notoginseng. The maximum values of leaf morpho-physiological traits, photosynthetic rate, and photosynthetic N use efficiency (PNUE) were obtained in the N15-grown P. notoginseng. Coefficients for leaf N allocation into the carboxylation and light-harvesting system components in the N0-grown plants were significantly higher than others. N0 and N7.5 plants showed higher K phase. N addition decreased the absorption and capture of the light energy per unit area (ABS/RC and TRO/RC) and non-photochemical quenching (NPQ). Photochemical quenching (qP), electron transport rate (ETR), and effective quantum yield of photosystem II (ϕPSII) were reduced in the N0-grown plants. The reduction of light-harvesting and utilization capacity not only leads to a decrease in PNUE, but also induces the damage of PSII reaction center. Overall, the inhibition of leaf growth and photosynthetic capacity is an essential strategy for high-N sensitive and shade-tolerant plants in response to N deficiency. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate dentinal tubule penetration of the root canal filling material using various techniques such as cold lateral compaction, new generation thermoplastic core carrier and continuous‐wave obturation. The root canals of premolar teeth were instrumented, and the teeth were allocated randomly to three groups (n = 15/group). After the obturation with three different techniques, three sections of 2‐mm thickness at 2, 5 and 8‐mm from the apex were examined under a confocal laser scanning microscope. The data were analysed of variance with a significance level of P < 0.05. There was no significant difference between techniques when parameters were evaluated in total (penetration depth P = 0.418, penetration area P = 0.701). The mean value of the cold lateral compaction group for maximum penetration depth was obtained higher than continuous wave (P = 0.004), whilst there was no significant difference between the thermoplastic core carrier and the other groups. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: There are few studies in the literature about the effect of obturation techniques on postoperative pain. Besides, GuttaFlow2 was used for the first time in this study regarding postoperative pain. This study aimed to compare the postoperative pain levels and incidence following single-visit root canal treatment with different canal filling techniques; cold lateral compaction (CLC), thermoplasticised solid-core carrier (GuttaCore) based filling and cold free-flow compaction (GuttaFlow2) technique. Methods: The patients (n = 93) having single-rooted teeth with a single canal diagnosed with asymptomatic irreversible pulpitis or single-rooted vital teeth with a single canal requiring endodontic treatment because of prosthetic reasons were enrolled in this study. Patients were randomized into three groups (n = 31) according to the obturation technique. A single operator performed all the treatments in a single visit. Data on obturation levels, postoperative pain and analgesic intake frequency were recorded at postoperative 6, 12 and 24 h and daily afterward until the 7th day. Postoperative pain was measured by visual analogue scale (VAS). The date were statistically analyzed with chi-squared tests (for the analyses of the categorical data), the nonparametric Kruskal-Wallis test (for the comparisons of VAS score) and with the Friedman test (for the assessments of the changes in VAS scores over time). Results: The GuttaCore group recorded the higher pain levels, except first 12 h, on the other hand, the GuttaFlow2 group recorded the lower pain levels at all time periods. Significant differences occurred among the groups during the first 4 days (p < 0.05), except at 12 h (p = 0.054). The patients in the CLC and GuttaFlow2 groups did not need to use the prescribed analgesic; however, one patient in the GuttaCore group used it once. Conclusions: Postoperative pain levels following root canal therapy were affected by the obturation technique especially first 4 days following obturation. [ABSTRACT FROM AUTHOR]

Copyright of Uni-Pluri/Versidad is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Capture, storage and subsequent controlled release or transformation of sulfur dioxide (SO2) in mild conditions is still a challenge in the material science field. Recent advances in the use of porous materials have demonstrated good SO2 capture, particularly in metal‐organic frameworks (MOFs), metal‐organic cages (MOCs), and porous organic cages (POCs). The striking feature of these porous materials is the high SO2 uptake capacity in reversible settings. A partially fluorinated MIL‐101(Cr) is stand‐alone material with the highest SO2 uptake in chemically stable MOFs. Likewise, metal‐free adsorbents like POCs exhibits a reversible SO2 uptake behavior. The SO2 adsorption characteristics of these three structurally and functionally unique adsorbent systems are highly dependent on the binding sites and mode of binding of SO2 molecules. This Review has highlighted the preferential binding sites in these materials to give a full perspective on the field. We anticipate that it will offer valuable information on the progress made towards improving SO2 capture by hybrid systems. [ABSTRACT FROM AUTHOR]

Copyright of Turkiye Klinikleri Journal of Dental Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Four chitosan‐poly(vinyl chloride), Cs‐PVC, conjugates were synthesized by primarily reacting amino‐PVC with chloroacetyl chloride to give 2‐chloro‐N‐(2‐aminoethyl) acetamide‐functionalized PVC (PVC‐AcCl) followed by conjugation with chitosan to yield a derivative of acetamide‐functionalized PVC chitosan (Cs‐AcPVC). On the other hand, a one‐pot reaction between PVC‐chloroacetyl chloride, benzimodazole, and chitosan produced benzimodazole‐functionalized PVC conjugates (PVC1). The above one‐pot reaction was repeated with incorporating silver nanoparticles, AgNPs, via in situ reduction of Ag salt to give PVC2 whereas silver treated titanium dioxide (Ag/TiO2)NPs was simply mixed with PVC1 to afford PVC3. Fourier‐transform infrared spectroscopy FTIR spectroscopic analyses of all the synthesized materials were studied. Morphological investigation such as scanning and transmission electron microscopy, and thermal gravimetric analysis were also carried out. The antibacterial activities of the synthesized conjugates were investigated against two Gram‐negative (Escherichia coli, and Salmonella typhimurium) and two Gram‐positive (Staphylococcus aureus, and Listeria monocytogenes) bacterial strains. The antibacterial assay showed that all PVC‐Cs conjugates exhibited excellent bacterial inhibition (five‐log10 reduction) at a concentration of 500 mg/L after 30 min and almost complete inhibition after 120 min. Minimum inhibition concentration investigation showed that conjugates PVC‐chloroacetyl chitosan and PVC3 were more potent than PVC1 and PVC2 against both Gram‐negative and Gram‐positive strains at 250 mg/L. These results suggested that all four polymeric conjugates might afford a revolutionary antibacterial polymeric material that can be useful in many applications such as water sanitization, food packaging, and biomedical devices. [ABSTRACT FROM AUTHOR]

In this work, we investigate the effects of water on the structural stability of Mn2(DSBDC) metal–organic framework (MOF) using DFT-based calculations. It has been found that the adsorption of multiple water molecules forming a hydrogen bond network around the Mn centers plays an important role in the decomposition process. Different effects contribute to the destabilization of the MOF: water molecules that directly coordinate to the open sites displayed by a part of the Mn centers can induce a significant shift in the charge distribution as indicated by the analysis of charge density differences and the Bader charges. This adsorption process leads to a slight elongation of the metal-linker bonds. The direct interaction with the Mn center is the most stable adsorption mode for water in Mn2(DSBDC). Once these adsorption sites at the Mn centers are fully occupied, additional water molecules start to bind via hydrogen bonds to the already present water molecules or, more importantly, to the linker molecules. This, in return, leads to a significant weakening of the Mn-linker bonds, thus allowing water insertion into the Mn-linker bonds with a barrier of only 0.16 eV, which is believed to initiate the decomposition of the Mn2(DSBDC) framework. Based on a kinetic Monte Carlo model, it can be shown that high temperatures can prevent the adsorption of water molecules around the Mn sites and thus slow down the MOF decomposition. [ABSTRACT FROM AUTHOR]

Herein, we report a pre‐synthetic pore environment design strategy to achieve stable methyl‐functionalized metal–organic frameworks (MOFs) for preferential SO2 binding and thus enhanced low (partial) pressure SO2 adsorption and SO2/CO2 separation. The enhanced sorption performance is for the first time attributed to an optimal pore size by increasing methyl group densities at the benzenedicarboxylate linker in [Ni2(BDC‐X)2DABCO] (BDC‐X=mono‐, di‐, and tetramethyl‐1,4‐benzenedicarboxylate/terephthalate; DABCO=1,4‐diazabicyclo[2,2,2]octane). Monte Carlo simulations and first‐principles density functional theory (DFT) calculations demonstrate the key role of methyl groups within the pore surface on the preferential SO2 affinity over the parent MOF. The SO2 separation potential by methyl‐functionalized MOFs has been validated by gas sorption isotherms, ideal adsorbed solution theory calculations, simulated and experimental breakthrough curves, and DFT calculations. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report the first experimental investigation of porous organic cages (POCs) for the demanding challenge of SO2 capture. Three structurally related N‐containing cage molecular materials were studied. An imine‐functionalized POC (CC3) showed modest and reversible SO2 capture, while a secondary‐amine POC (RCC3) exhibited high but irreversible SO2 capture. A tertiary amine POC (6FT‐RCC3) demonstrated very high SO2 capture (13.78 mmol g−1; 16.4 SO2 molecules per cage) combined with excellent reversibility for at least 50 adsorption–desorption cycles. The adsorption behavior was investigated by FTIR spectroscopy, 13C CP‐MAS NMR experiments, and computational calculations. [ABSTRACT FROM AUTHOR]

Copyright of Revista Kavilando is the property of Kavilando and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Reactive gas formation in pores of metal–organic frameworks (MOFs) is a known mechanism of framework destruction; understanding those mechanisms for future durability design is key to next generation adsorbents. Herein, an extensive set of ab initio molecular dynamics (AIMD) simulations are used for the first time to predict competitive adsorption of mixed acid gases (NO2 and H2O) and the in‐pore reaction mechanisms for a series of rare earth (RE)‐DOBDC MOFs. Spontaneous formation of nitrous acid (HONO) is identified as a result of deprotonation of the MOF organic linker, DOBDC. The unique DOBDC coordination to the metal clusters allows for proton transfer from the linker to the NO2 without the presence of H2O and may be a factor in DOBDC MOF durability. This is a previously unreported mechanisms of HONO formation in MOFs. With the presented methodology, prediction of future gas interactions in new nanoporous materials can be achieved. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carriers such as alcohols and polyols are a high-capacity means of transporting and reversibly storing hydrogen that demands effective catalysts to drive the (de)hydrogenation reactions under mild conditions. We employed a combined theory/experiment approach to develop MOF-74 catalysts for alcohol dehydrogenation and examine the performance of the open metal sites (OMS), which have properties analogous to the active sites in high-performance single-site catalysts and homogeneous catalysts. Methanol dehydrogenation was used as a model reaction system for assessing the performance of five monometallic M-MOF-74 variants (M = Co, Cu, Mg, Mn, Ni). Co-MOF-74 and Ni-MOF-74 give the highest H2 productivity. However, Ni-MOF-74 is unstable under reaction conditions and forms metallic nickel particles. To improve catalyst activity and stability, bimetallic (NixMg1−x)-MOF-74 catalysts were developed that stabilize the Ni OMS and promote the dehydrogenation reaction. An optimal composition exists at (Ni0.32Mg0.68)-MOF-74 that gives the greatest H2 productivity, up to 203 mL gcat−1 min−1 at 300 °C, and maintains 100% selectivity to CO and H2 between 225–275 °C. The optimized catalyst is also active for the dehydrogenation of other alcohols. DFT calculations reveal that synergistic interactions between the open metal site and the organic linker lead to lower reaction barriers in the MOF catalysts compared to the open metal site alone. This work expands the suite of hydrogen-related reactions catalyzed by MOF-74 which includes recent work on hydroformulation and our earlier reports of aryl-ether hydrogenolysis. Moreover, it highlights the use of bimetallic frameworks as an effective strategy for stabilizing a high density of catalytically active open metal sites. [ABSTRACT FROM AUTHOR]

Generating computational anatomical models of cerebrovascular networks is vital for improving clinical practice and understanding brain oxygen transport. This is achieved by extracting graph-based representations based on pre-mapping of vascular structures. Recent graphing methods can provide smooth vessels trajectories and well-connected vascular topology. However, they require water-tight surface meshes as inputs. Furthermore, adding vessels radii information on their graph compartments restricts their alignment along vascular centerlines. Here, we propose a novel graphing scheme that works with relaxed input requirements and intrinsically captures vessel radii information. The proposed approach is based on deforming geometric graphs constructed within vascular boundaries. Under a laplacian optimization framework, we assign affinity weights on the initial geometry that drives its iterative contraction toward vessels centerlines. We present a mechanism to decimate graph structure at each run and a convergence criterion to stop the process. A refinement technique is then introduced to obtain final vascular models. Our implementation is available on https://github.com/Damseh/VascularGraph. We benchmarked our results with that obtained using other efficient and state-of-the-art graphing schemes, validating on both synthetic and real angiograms acquired with different imaging modalities. The experiments indicate that the proposed scheme produces the lowest geometric and topological error rates on various angiograms. Furthermore, it surpasses other techniques in providing representative models that capture all anatomical aspects of vascular structures. [ABSTRACT FROM AUTHOR]

Detection and capture of toxic nitrogen oxides (NOx) is important for emissions control of exhaust gases and general public health. The ability to directly electrically detect trace (0.5–5 ppm) NO2 by a metal–organic framework (MOF)‐74‐based sensor at relatively low temperatures (50 °C) is demonstrated via changes in electrical properties of M‐MOF‐74, M = Co, Mg, Ni. The magnitude of the change is ordered Ni > Co > Mg and explained by each variant's NO2 adsorption capacity and specific chemical interaction. Ni‐MOF‐74 provides the highest sensitivity to NO2; a 725× decrease in resistance at 5 ppm NO2 and detection limit <0.5 ppm, levels relevant for industry and public health. Furthermore, the Ni‐MOF‐74‐based sensor is selective to NO2 over N2, SO2, and air. Linking this fundamental research with future technologies, the high impedance of MOF‐74 enables applications requiring a near‐zero power sensor or dosimeter, with the active material drawing <15 pW for a macroscale device 35 mm2 with 0.8 mg MOF‐74. This represents a 104–106× decrease in power consumption compared to other MOF sensors and demonstrates the potential for MOFs as active components for long‐lived, near‐zero power chemical sensors in smart industrial systems and the internet of things. [ABSTRACT FROM AUTHOR]

A cucurbit[6]uril cage-based hydrogen-bonded organic framework (HOF) shows high capacity of SO2 capture (up to 4.98 mmol g−1 at 1 bar and 293 K), high SO2/CO2 selectivity, good chemical stability toward dry SO2, and outstanding cycling performance. The preferential adsorption sites on the cage of the HOF are revealed by DFT calculations and FT-IR. [ABSTRACT FROM AUTHOR]

Functionalization of metal–organic framework (MOF) ligands can tune the adsorption properties of MOFs. The adsorptions of NO, NO2, NH3, C5H5N, C4H5N, and C4H4O on pristine and five X-functionalized HKUST-1, i.e. Cu3(BTC)2 (BTC = 1,3,5-benzenetricarboxylate) (X = CH3, CH3O, NH2, NO2, and Br) are evaluated by van der Waals corrected density functional theory calculations. Despite the fact that the open metal center is the energetically preferred adsorption site for most of them, the functional group site can yield a comparable adsorption ability with the open metal center. This is particularly true for pyrrole C4H5N adsorption on CH3O-functionalized HKUST-1 where the functional group site shows stronger adsorption stability than the open metal center site, probably due to the formed hydrogen bond between pyrrole and the CH3O functional group. While the CH3- or CH3O-functionalized organic linker in these MOFs strengthens the adsorption of all the considered species, that of NO2-, Br-, or NH2-functional groups reduces, which is associated with their topologies. Among them, only CH3- or CH3O-functionalized HKUST-1 presents the fmj (orthorhombic crystal system) topology while all the others are isostructural to the pristine HKUST-1 with the tbo (twisted boracite-type, cubic) topological structure. Among six adsorbates, two basic adsorbates, C5H5N and NH3, always yield the strongest bonding strength upon adsorption on the pristine and five functionalized HKUST-1. Electronic properties including the Bader charges, electron density differences, and electron localization function were investigated to comprehend their adsorption behaviors. This work provides guidance for the proper functionalization of HKUST-1 with improved adsorption properties for specific adsorbates. [ABSTRACT FROM AUTHOR]

Direct CO2 conversion from flue gas into high-value products is of great significance not only in relieving environmental burden but alleviating the energy crisis by a low-cost and energy-saving avenue, yet few studies in this aspect have been reported. Herein, we report metal-node-dependent catalytic performance for solar-energy-powered CO2 reduction to formate in simulated flue gas by bimetallic Ni/Mg-MOF-74. The yield of HCOO− with Ni0.75Mg0.25-MOF-74 as a catalyst in pure CO2 is 0.64 mmol h−1 gMOF−1 which is higher than that of Ni-MOF-74 (0.29 mmol h−1 gMOF−1) and Ni0.87Mg0.13-MOF-74 (0.54 mmol h−1 gMOF−1), whereas monometallic Mg-MOF-74 is almost inactive, indicating that reactivity relies on metal nodes. In simulated flue gas without water vapor at 20 °C, ∼80% of the reactivity in pure CO2 is retained, with HCOO− generation reaching 0.52 mmol h−1 gMOF−1. This activity is comparable to that of the best MOF catalysts in pure CO2, demonstrating that Ni/Mg-MOF-74 not only overcomes the limitation from CO2 concentration, but also has good resistance to other gas components in flue gas at 20 °C. DFT calculations reveal the high output for HCOO− from two crucial factors: strong CO2 binding affinity of Mg sites, and the synergistic effect of Mg and Ni leading to the stabilization of the key *OCOH intermediate with an appropriate energy barrier. This work paves a new route for double-metal MOFs to enhance the CO2 photoreduction reactivity in flue gas. [ABSTRACT FROM AUTHOR]

Partially fluorinated MIL-101(Cr) shows high SO2 capture (up to 18.4 mmol g−1 at 298 K and up to 1 bar), chemical stability towards dry and humid SO2 and an outstanding cycling performance with facile regeneration. In situ DRIFT spectroscopy demonstrated the preferential adsorption sites within MIL-101(Cr)-4F(1%). [ABSTRACT FROM AUTHOR]

Root canal treatment failure can be determined based on a patient's complaint and on the basis of clinical examination and radiographic findings. Most of the signs and symptoms for the failure are pain and discomfort, swelling and sinus formation at the surrounding soft tissue, and discoloration of the subjected tooth. Factors such as mechanical perforation during the procedures, overfilled or underfilled root canal, and missed or unfilled canals are the main factors for the failure outcome. This case report presents a discolored and infected upper lateral incisor which was previously root canal treated. The tooth was successfully managed under nonsurgical and surgical retreatment followed by an internal bleaching and full porcelain veneer. Apical tissue healing and acceptable tooth appearance was observed during a 12-month review. [ABSTRACT FROM AUTHOR]