Bridge Formation Research Articles

Analytical assessment of the full-bridge response to the vertical live load: An algorithm for hybrid cable-stayed suspension bridges

Hybrid cable-stayed suspension bridges combine the advantages of cable-stayed and suspension bridges, mitigating their deficiencies. Due to its super spanning ability, this novel form of bridge enjoys a bright application prospect as a large-span structure. This study introduces an analytical algorithm to estimate the full-bridge response of a hybrid cable-stayed suspension bridge with a vertical uniformly distributed load applied to the main beam. This method is based on the assumption that all parameters, such as the geometric configuration, internal force distribution, and material properties, of the whole bridge under a dead load are known; then, it analyzes the full-bridge response under a live load. First, the minimum and independent basic unknown parameters of the full-bridge response are determined. Next, the governing equations are derived and solved based on the conservation of unstressed length of each section of cable, closure of span lengths and elevation difference in different spans, and conditions for stress balance of the main beam. Thus, the values of basic unknown parameters are obtained. Finally, they are substituted into the governing equations to estimate the full-bridge response, including each bridge component’s internal forces and deflections. The proposed analytical method involves no iterative procedures when dealing with nonlinear problems but only focuses on the bridge’s state with and without loading. The results are obtained directly by solving the equations, which have the advantages of high efficiency, simplicity, and clear physical meaning. Finally, the feasibility and effectiveness of the proposed method are verified by a finite-element-based calculation of an exemplary asymmetric cable-stayed suspension cooperation system bridge with a main span of 1400 m.

Rapid Formation of Intramolecular Disulfide Bridges using Light: An Efficient Method to Control the Conformation and Function of Bioactive Peptides.

Disulfide bonds are widely found in natural peptides and play a pivotal role in stabilizing their secondary structures, which are highly associated with their biological functions. Herein, we introduce a light-mediated strategy to effectively control the formation of disulfides. Our strategy is based on 2-nitroveratryl (oNv), a widely used photolabile motif, which serves both as a photocaging group and an oxidant (after photolysis). We demonstrated that irradiation of oNv-caged thiols with UV light could release free thiols that are rapidly oxidized by locally released byproduct nitrosoarene, leading to a "break-to-bond" fashion. This strategy is highlighted by the in situ restoration of the antimicrobial peptide tachyplesin I (TPI) from its external disulfide-caged analogue TPI-1. TPI-1 exhibits a distorted structure and a diminished function. However, upon irradiation, the β-hairpin structure and membrane activity of TPI were largely restored via rapid intramolecular disulfide formation. Our study proposes a powerful method to regulate the conformation and function of peptides in a spatiotemporal manner, which has significant potential for the design of disulfide-centered light-responsive systems.

Organo-mineral associations and size-fractionated colloidal organic carbon dynamics in a redox-controlled wetland

The formation of organo-mineral associations serves as a crucial mechanism for stabilizing soil organic matter, particularly for determining the fate of soil organic carbon (OC) in redox dynamic wetlands characterized by high C content. Despite its importance, few studies have assessed the retention, transformation, and transport of colloids (1–1000 nm) and colloidal OC (COC) in those environments. This leaves a crucial knowledge gap concerning the quantities of colloids and COC and their molecular compositions, especially considering the significant role of metabolically active depressional wetlands that may play as biogeochemical hotspots for C cycling. To address this gap, we conducted a study in a Delmarva Bay depressional wetland located in Blackbird State Forest, Delaware, USA. We established a transect encompassing upland (U), transition (T), and wetland (W) zones based on seasonal hydrologic conditions. We installed piezometers at 50 cm, 100 cm, and 200 cm depths within each zone and collected pore-water samples from 11/2017 to 05/2019. We then fractionated these samples into dissolved (<2.3 nm), natural nanoparticle (NNP, 2.3–100 nm), fine colloid (100–450 nm), and particulate (450–1000 nm) fractions via sequential centrifugation and ultrafiltration, and quantified their concentration and molecular composition. We observed variations in the concentration and molecular composition of soil COC both vertically at different soil depths and horizontally along a redox gradient from the U-T-W transect. The sum of the NNP and fine colloid fractions accounted for 47±20% of the operationally defined “dissolved” (<450 nm) fraction. Isotope ratio mass spectrometry and X-ray photoelectron spectroscopy analyses further revealed that the NNP fraction is more enriched in heavier δ13C isotope and oxidized carbonyl/carboxyl C functional groups (C=O, p<0.05) with significantly higher surficial atomic percentages of C (p<0.01), N (p<0.01), and Mg:Al ratios (p<0.05), and lower atomic percentages of Al (p<0.01) and Si (p<0.01) compared to the larger particles. The formation of cation bridges and/or hydrogen bonds between carboxylic OC and phyllosilicate minerals likely dominated the mineral-OC association in the NNP fraction. The higher surface C enrichment in the particulate fraction compared to the NNP fraction suggests a patchy distribution of more plant-derived OC through organo-organic interactions in the larger fractions. Along the transect, Zone U exhibited significant enrichment of heavier δ13C isotope and lower SUVA values than the Zones T and W indicating inefficient decomposition and dissociation of SOM from minerals due to the reductive dissolution of Fe and Al oxides under anoxic conditions. Furthermore, an increase in low molecular weight microbial metabolites with reduced aromatic OC content was observed at deeper depths in Zones U and T. Our study provides new insights into the concentration and molecular composition of size-fractionated COC, highlighting the need to separately consider the NNP and fine colloid fractions from the operationally defined “dissolved” phase. This is crucial for assessing the biogeochemical cycling of OC in redox-active wetlands, a pressing need amidst the growing concerns about the impacts of climate change.

POT1 involved in telomeric DNA damage repair and genomic stability of cervical cancer cells in response to radiation.

Though telomeres play a crucial role in maintaining genomic stability in cancer cells and have emerged as attractive therapeutic targets in anticancer therapy, the relationship between telomere dysfunction and genomic instability induced by irradiation is still unclear. In this study, we identified that protection of telomeres 1 (POT1), a single-stranded DNA (ssDNA)-binding protein, was upregulated in γ-irradiated HeLa cells and in cancer patients who exhibit radiation tolerance. Knockdown of POT1 delayed the repair of radiation-induced telomeric DNA damage which was associated with enhanced H3K9 trimethylation and enhanced the radiosensitivity of HeLa cells. The depletion of POT1 also resulted in significant genomic instability, by showing a significant increase in end-to-end chromosomal fusions, and the formation of anaphase bridges and micronuclei. Furthermore, knockdown of POT1 disturbed telomerase recruitment to telomere, and POT1 could interact with phosphorylated ATM (p-ATM) and POT1 depletion decreased the levels of p-ATM induced by irradiation, suggesting that POT1 could regulate the telomerase recruitment to telomeres to repair irradiation-induced telomeric DNA damage of HeLa cells through interactions with p-ATM. The enhancement of radiosensitivity in cancer cells can be achieved through the combination of POT1 and telomerase inhibitors, presenting a potential approach for radiotherapy in cancer treatment.

Impact of Endogenous Pneumococcal Hydrogen Peroxide on the Activity and Release of Pneumolysin.

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia. The pore-forming cholesterol-dependent cytolysin (CDC) pneumolysin (PLY) and the physiological metabolite hydrogen peroxide (H2O2) can greatly increase the virulence of pneumococci. Although most studies have focused on the contribution of both virulence factors to the course of pneumococcal infection, it is unknown whether or how H2O2 can affect PLY activity. Of note, S. pneumoniae exploits endogenous H2O2 as an intracellular signalling molecule to modulate the activity of several proteins. Here, we demonstrate that H2O2 negatively affects the haemolytic activity of PLY in a concentration-dependent manner. Prevention of cysteine-dependent sulfenylation upon substitution of the unique and highly conserved cysteine residue to serine in PLY significantly reduces the toxin's susceptibility to H2O2 treatment and completely abolishes the ability of DTT to activate PLY. We also detect a clear gradual correlation between endogenous H2O2 generation and PLY release, with decreased H2O2 production causing a decline in the release of PLY. Comparative transcriptome sequencing analysis of the wild-type S. pneumoniae strain and three mutants impaired in H2O2 production indicates enhanced expression of several genes involved in peptidoglycan (PG) synthesis and in the production of choline-binding proteins (CPBs). One explanation for the impact of H2O2 on PLY release is the observed upregulation of the PG bridge formation alanyltransferases MurM and MurN, which evidentially negatively affect the PLY release. Our findings shed light on the significance of endogenous pneumococcal H2O2 in controlling PLY activity and release.

Effect of Water Models on The Stability of RNA: Role of Counter-Ions

Various force fields and water model potentials influence significantly RNA conformations. The polyanionic nature of RNA attracts the water molecules and the counter ions which in turn affects their stability. The interfacial water's structural and dynamic aspects affect the RNA's base-pair opening and denaturation by breaking or making inter/intra-hydrogen bonds. Herein, we employed an MD simulations study using SPC/E and modified TIP3P water models in combination with different force fields CHARMM and AMBER to find their influence on the hydration shell of the SARS-CoV-2 RNA genome at different temperatures. AMBER-mTIP3P model was found to give more dynamic and transient conformations for RNA. The lower dielectric constant of the SPC/E model helps in the formation of the ion-contact pair near the negatively charged phosphate group (Na+-PO4−) leading to strong RNA-ion interaction and strong hydration shells having higher hydrogen bond lifetime. The Na+ ion survival probability at the interface was found to be more in the SPC/E model. At lower temperatures, the water molecules inside these hydration shells were found to be inhomogeneous, with lower void space, higher-coordinated, and non-tetrahedral. The higher dielectric constant of the mTIP3P model screened out the attraction between the ion pairs leading to a more homogenous solvation shell having a lesser hydrogen bond lifetime and more diffusive water. The distribution of the ions near the RNA structure is confirmed by metadynamics simulations. Both water models were found to disrupt the base pair orientation due to the formation of water bridges between the O2ʹ group of RNA and the water molecules.

Endogenous tenocyte activation underlies the regenerative capacity of the adult zebrafish tendon

Tendons are essential, frequently injured connective tissues that transmit forces from muscle to bone. Their unique highly ordered, matrix-rich structure is critical for proper function. While adult mammalian tendons heal after acute injuries, endogenous tendon cells, or tenocytes, fail to respond appropriately, resulting in the formation of disorganized fibrovascular scar tissue with impaired function and increased propensity for re-injury. Here, we show that, unlike mammals, adult zebrafish tenocytes activate upon injury and fully regenerate the tendon. Using a full tear injury model in the adult zebrafish craniofacial tendon, we defined the hallmark stages and cellular basis of tendon regeneration through multiphoton imaging, lineage tracing, and transmission electron microscopy approaches. Remarkably, we observe that zebrafish tendons regenerate and restore normal collagen matrix ultrastructure by 6 months post-injury (mpi). Tendon regeneration progresses in three main phases: inflammation within 24 h post-injury (hpi), cellular proliferation and formation of a cellular bridge between the severed tendon ends at 3–5 days post-injury (dpi), and re-differentiation and matrix remodeling beginning from 5 dpi to 6 mpi. Importantly, we demonstrate that pre-existing tenocytes are the main cellular source of regeneration, proliferating and migrating upon injury to ultimately bridge the tendon ends. Finally, we show that TGF-β signaling is required for tenocyte recruitment and bridge formation. Collectively, our work debuts and aptly positions the adult zebrafish tendon as an invaluable comparative system to elucidate regenerative mechanisms that may inspire new therapeutic strategies.

On-chip full bridge bipolar linear spin valve sensors through modified synthetic antiferromagnetic layers

Realizing the rising demand for high-sensitivity magneto-resistive (MR) sensors in the industry, an attempt was made towards the fabrication of a spin valve (SV) based bipolar sensor on chip in the form of a full Wheatstone bridge with push–pull configuration. For a sensor with a push–pull configuration, the opposite arms are configured with opposite sense layers. To achieve this, either odd or even layers of synthetic antiferromagnetic (SAF) structure were introduced in the conventional spin valve structure, through which the magnetization orientation of the sensing layer was regulated by either negative or positive sensitivity to the applied field direction respectively. A detailed theoretical simulation was carried out to achieve the stable antiparallel magnetic state around zero fields by varying individual layer thicknesses in the case of single and double-layer SAF structures. With optimized conditions, experimental data were presented, and a bipolar device with a sensitivity of the order of 0.7 mV/V/Oe in the linear field range of ± 15 Oe was fabricated. The performance of the device was characterized by a wider temperature range and it was observed that the device has high thermal stability in the range of - 40 °C to 125 °C with a thermal coefficient of the voltage around 12 μV/V/∘C. Angular performance of the fabricated sensor with minimized orthogonality error was presented and it was observed that the sensor can measure the angle with an accuracy of +/-2 ° .

Understanding the formation of “false friends” (hidden lack of fusion defects) in laser beam welding by means of high-speed synchrotron X-ray imaging

This paper provides a fundamental understanding of “false friend” formation, i.e., hidden defects associated with lack of fusion, using an experimental setup that allowed an insight into the processing zone based on high-speed synchrotron X-ray imaging. The setup enabled the welding of a lap joint of AISI 304 high-alloy steel sheets (X5CrNi18-10/1.4301), with the ability to adjust different gap heights between top and bottom sheet (up to 0.20 mm) and to acquire high-speed X-ray images at 100 kHz simultaneously with the welding process. On this basis, a time-resolved description of the “false friend” formation can be provided by visualizing the interaction between keyhole and melt pool during laser welding and solidification processes within the gap area. The bridgeability of the gap was limited due to the gap height and insufficient melt supply leading to the solidification of the bridge. The distance between the solidified bridge and the keyhole increased with time, while the keyhole and melt pool dynamics initiated the formation of new melt bridges whose stability was defined by melt flow conditions, surface tension, and gap heights. The alternating formation and solidification of melt bridges resulted in entrapped areas of lacking fusion within the weld, i.e., “false friends.” Finally, based on the results of this study, a model concept is presented that concludes the main mechanisms of “false friend” formation.

Comparative efficacy of materials used in patients undergoing pulpotomy or direct pulp capping in carious teeth: A systematic review and meta-analysis.

Different materials have been used for capping the pulp after exposure during caries removal in permanent teeth. The purpose of this study was to collate and analyze all pertinent evidence from randomized controlled trials (RCTs) on different materials used in patients undergoing pulpotomy or direct pulp capping in carious teeth. Trials comparing two or more capping agents used for direct pulp capping (DPC) or pulpotomy were considered eligible. An electronic search of four databases and two clinical trial registries was carried out up to February 28, 2021 using a search strategy properly adapted to the PICO framework. Screening, data extraction, and risk of bias (RoB) assessment of primary studies were performed in duplicate and independently. The primary outcome was clinical and radiological success; secondary outcomes included continued root formation, tooth discoloration, and dentin bridge formation. 21 RCTs were included in the study. The RoB assessment indicated a moderate risk among the studies. Due to significant clinical and statistical heterogeneity among the studies, performing network meta-analysis (NMA) was not possible. An ad hoc subgroup analysis revealed strong evidence of a higher success of DPC with Mineral Trioxide Aggregate (MTA) compared to calcium hydroxide (CH) (odds ratio [OR] = 3.10, 95% confidence interval [CI]: 1.66-5.79). MTA performed better than CH in pulp capping (both DPC and pulpotomy) of mature compared to immature teeth (OR = 3.34, 95%CI: 1.81-6.17). The GRADE assessment revealed moderate strength of evidence for DPC and mature teeth, and low to very low strength of evidence for the remaining subgroups. Considerable clinical and statistical heterogeneity among the trials did not allow NMA. The ad hoc subgroup analysis indicated that the clinical and radiographic success of MTA was higher than that of CH but only in mature teeth and DPC cases where the strength of evidence was moderate.PROSPERO Registration: number CRD42020127239.

Clinical-therapeutical management of exposed pulp and incomplet apexogenesis: Cases reports

The study of bioactive materials, such as MTA cement, and the availability of this material to clinical professionals are an important step towards conservative treatments, however the using technique of this material is still restricted to practitioners in the field of endodontics. Case reports with short, medium and long-term follow-up are significant data for a reproducible, low-cost technique that is well accepted among professionals. Here we present two case reports with the application of bioactive cements in a tooth with pulp exposure and in another one with deep carious lesion, pulp exposure and open apex. In both cases, definitive restoration was performed in the same visit with favorable prognosis and without the need of endodontic treatment. After one year follow-up, it is underlined the dentin bridge formation in the region of pulp exposure in both cases and complete maturation of the apex in the second case.

Facile approach to fabricate stable multi-chamber colloid particles for compartmentalized encapsulation and reaction control of incompatible molecules

Compartmentalized delivery systems can achieve simultaneous encapsulation of multiple guest cargos in independent spaces and are becoming a topic of tremendous interest in medical and food disciplines. Herein, we reported a top-down assisted bottom-up approach to fabricate stable multi-chamber colloid (MCC) particles by using ferritin nanocages, which can be applied for compartmentalized loading of incompatible guest cargos. Our results demonstrated that the size of MCC particles can be regulated by controlling synthetic parameters. The primary amines of arginine and lysine residues distributed over the exterior surface and subunit-subunit interfaces of ferritin are responsible for the formation of covalent crosslinking bridges, thus, stabilizing the compartmentalized structure of MCC particles with pH value even lower to ∼2.0. Remarkably, by choosing Nile-red and FITC as guest cargos, LSCM images clearly demonstrated that Nile-red and FITC are compartmentalized encapsulated within each MCC particle, illustrating the compartmentalized loading capacity of MCC particles. Moreover, the MCC structures feature highly sealed independent compartments. When two incompatible guest cargos, chlorogenic acid (ChA) and iron core nanoparticles, are compartmentalized loaded within MCC particles, the protein shell barrier can efficiently hinder their physical contact and inhabit the redox reaction. Conversely, upon structural destruction, ChA and iron core nanoparticles are co-released and the redox reaction can be triggered, ultimately leading to the controlled release of ferrous ions for iron supplementation. This study provided a facile strategy for the construction of stable compartmentalized delivery systems, which have great potential for co-delivery of incompatible molecules in food and medical disciplines.

Exploring thermal isomerisation in gas chromatography analyses using natural pyrethrins: Comparison of comprehensive two-dimensional and one-dimensional gas chromatography

This study aims to assess and qualitatively compare the visual presentation of chromatographic data from the isomerisation of natural pyrethrins – a group of pesticides derived from Chrysanthemum flowers – using one-dimensional gas chromatography (1DGC) and comprehensive two-dimensional gas chromatography (GC×GC). Molecular structural changes, such as thermal isomerisation in this case, occur during gas chromatography injection and separation, to provide characteristic patterns which may not be routinely recognised on the 1D chromatogram. To demonstrate the influence of analytical method parameters on isomerisation processes, variations in oven temperature (isothermal vs. temperature programmed analysis), inlet mode (split vs. splitless), inlet temperature, and carrier gas flow rate were investigated. Increasing oven temperature was the most significant factor affecting isomerisation. Splitless injection mode and increasing inlet temperature promoted isopyrethrin formation, while the effect of inlet temperature appeared minimal with a split injection technique, most likely due to the short residence time in the inlet. Increased carrier gas flow rates in a temperature programmed analysis reduced retention time and minimised isomerisation. The unique presentation of isopyrethrin peaks on a GC×GC contour plot allows for facile recognition of isomerisation especially at low concentrations, simplifies chromatogram interpretation, and aids in analyte identification. It also confirms that the isomerisation process is irreversible since the pyrethrin I and II compounds are absent throughout the bridge formation. These benefits support the use of GC×GC over 1DGC to study isomerisation. Additionally, due to limited data in the literature, Kováts retention indices and linear retention indices of the natural pyrethrins, including isopyrethrins, were experimentally determined on four columns: DB-5 ms UI, Rxi-17Sil MS, SLB-IL60i, and SLB-IL111i.

Assessment of steel bridges – cracking the code

This article has been developed from a presentation given at the IStructE conference on 'Structural rehabilitation' in December 2022. It gives a view, based on my career over 30 years, of the way in which our assessment codes can fall short in carrying out a structural assessment of steel bridges. I have taken three differing types of bridge form, scale and purpose, and explained the assessment problems encountered and the method by which a better solution was found using computer methods of analysis. The bridges chosen are the M5 Avonmouth Bridge, a steel box-girder structure; a single-span railway bridge over the River Wey, originally of wrought iron, but subsequently strengthened in steel; and, finally, a lattice-girder truss footbridge. Considering the ongoing pace of development in hardware and software power, and the relative falling cost of computer analysis, the suggestion is made that upcoming assessment codes should make better use of computer tools available.

Building Porous Ni(Salen)-Based Catalysts from Waste Styrofoam via Autocatalytic Coupling Chemistry for Heterogeneous Oxidation with Molecular Oxygen.

The development of robust and industrially viable catalysts from plastic waste is of great significance, and the facile construction of high performance heterogeneous catalyst systems for phenol-quinone conversions remains a grand challenge. Herein, a feasible strategy is demonstrated to reclaim Styrofoam into hierarchically porous nickel-salen-loaded hypercrosslinked polystyrene (PS@Ni-salen) catalysts with high activities through an unusual autocatalytic coupling route. The salen is immobilized onto PS chain by Friedel-Crafts alkylation of benzyl chloride derivatives, and the generated hydrogen chloride coordinately promotes the simultaneous crosslinking and bridge formation between aromatic rings via a Scholl coupling route, leading to hierarchically porous networks. After the metallization with Ni, the resultant networks exhibit high catalytic activity for the oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-1,4-benzoquinone under mild conditions (303 K, 1bar of O2 ). This catalyst also demonstrates attractive recycling performance without an obvious loss of catalytic efficiency over five consecutive cycles. This methodology might provide a potential sustainable alternative to construct environmentally benign and cost-effective catalysts for specific organic transformation.

A Low‐Binder‐Content Ink System for 3D Printing High‐Density and Small Feature Size 316L Stainless Steel Parts

Binder ink system is the backbone of binder jet 3D printing (BJ‐3DP) technology. Compared with metal injection molding (MIM), BJ‐3DP needs much less amount of binder, which means less exhaust gas generation during the debinding process and more environmental friendliness. More than that, low content of binder is also supposed to benefit the structure properties of the printed metal parts. Herein, an ultralow‐binder‐content ethanol–water–PVP ink system is demonstrated for the BJ‐3DP 316 L stainless steel parts by applying thermal bubble inkjet technology. The PVP binder concentration is as low as 80 mg mL−1, which can achieve an ultralow solid content of 0.2 wt% in the printed green part. The two‐component solution with water and ethanol provides not only the rheology property adjustment freedom for the ink jetting and infiltration in the metal powders, but also the two boiling points for the step‐by‐step capillary bridge formation process. By applying the low‐binder‐content ink, the fully densified 316 L stainless steel parts after sintering can obtain the relative density up to 99.4%, Vickers hardness up to 185 HV, tensile strength up to 542 MPa, 25% elongation at break, and feature size as small as 200 μm.

Large Photospheric Doppler Shift in Solar Active Region 12673. I. Field-aligned Flows

Delta (δ) sunspots sometimes host fast photospheric flows along the central magnetic polarity inversion line (PIL). Here we study the strong Doppler shift signature in the central penumbral light bridge of solar active region NOAA 12673. Observations from the Helioseismic and Magnetic Imager (HMI) indicate highly sheared and strong magnetic fields. Large Doppler shifts up to 3.2 km s−1 appeared during the formation of the light bridge and persisted for about 16 hr. A new velocity estimator, called DAVE4VMwDV, reveals fast converging and shearing motion along the PIL from HMI vector magnetograms, and recovers the observed Doppler signal much better than an old version of the algorithm. The inferred velocity vectors are largely (anti-)parallel to the inclined magnetic fields, suggesting that the observed Doppler shift contains a significant contribution from the projected field-aligned flows. High-resolution observations from the Hinode/Spectro-Polarimeter further exhibit a clear correlation between the Doppler velocity and the cosine of the magnetic inclination, which is in agreement with HMI results and consistent with a field-aligned flow of about 9.6 km s−1. The complex Stokes profiles suggest significant gradients of physical variables along the line of sight. We discuss the implications on the δ-spot magnetic structure and the flow-driving mechanism.

Histological evaluation of dental pulp response to Biodentine, enamel matrix derivative (Emdogain), and mineral trioxide aggregate as direct pulp-capping agents – A randomized clinical trial

ABSTRACT Aim: We aimed to study the response of pulp tissue to Biodentine, enamel matrix derivative (Emdogain), and mineral trioxide aggregate (MTA) as direct pulp-capping (DPC) agents. Materials and Methods: This study was performed on 78 maxillary/mandibular permanent teeth indicated for surgical extraction (periodontal/orthodontic). Exposure of 1.2 mm in diameter was made. Hemostasis was achieved. The tooth was randomly allocated to one of the three groups. In Group 1, pulp capping was done with Biodentine. In Group 2, Emdogain was used. In Group 3 (control), pulp capping was carried out with MTA. Final restoration was done with glass-ionomer cement. Teeth were extracted atraumatically after 6 weeks. Histologic examination was done and samples were evaluated. Differences in inflammatory response in the three groups were statistically evaluated using Chi-square test. Results: Grade 1 inflammatory response was observed in 57.7% of cases treated with Biodentine, 36% with Emdogain, and 65.4% with MTA. The difference was however not statistically significant (P = 0.427). Majority of cases in the MTA group (57.7%) showed presence of calcific bridge directly adjacent to the medicament interface as compared to Biodentine (46.1%) and Emdogain (0%), and the difference between the groups was statistically significant (P &lt; 0.05). The difference in formation of calcific bridge with MTA and Biodentine was not statistically significant (0.694). Conclusions: Within the limitations of this histological study, it can be concluded that MTA and Biodentine are well tolerated as DPC agents by pulp tissue as compared to Emdogain.

The Waukesha Biota: a wonderful window into early Silurian life

The Waukesha Biota (Brandon Bridge Formation Lagerstätte) is a diverse assemblage of early Silurian (437 Ma) shallow marine fossils from Wisconsin, USA. Their exceptional preservation, in finely laminated dolomitic mudstones, was mediated by tidally‐influenced conditions and/or microbial entombment. Shelly biomineralized animals are rare, but soft‐bodied organisms are common. Arthropods dominate, including trilobites, phyllocarids, ostracodes, a thylacocephalan, a synziphosurine and various enigmatic groups. The fauna also includes evolutionary ‘holdovers’, such as palaeoscolecids and a lobopodian.

Getting insight into the CO tolerance over Co-modified MnSm/Ti catalyst for NH3-SCR of NOx at low temperature: Experiments and DFT studies

The existence of carbon monoxide (CO) in industrial boilers flue gas can suppress the performance of the selective catalytic reduction with NH3 (NH3-SCR) for NOx removal at low temperatures over the Mn-based catalyst, and the related mechanism is needed to be revealed for improving the NH3-SCR performance. In this work, the effects of CO on the NH3-SCR performance over MnSm/Ti catalyst were studied, and the CO tolerance of the catalyst with cobalt (Co) modification at low temperatures was evaluated. The DFT calculations were performed to reveal the mechanism for the modification of Co over the MnSm/Ti catalyst. The NOx conversion for MnSm/Ti catalyst decreased by 15.2%-21.4% at 150–300 ℃ due to the presence of CO in the NH3-SCR reaction atmosphere. After introducing Co into MnSm/Ti catalyst, the NOx conversion for MnSmCo/Ti catalyst only decreased by 8.9%-13.8% at 150–300 ℃ with the presence of CO. It was evidenced that the CO tolerance of the MnSm/Ti catalyst was enhanced with the Co modification. The characterizations of catalysts revealed that the adsorptions of NH3 and NO over the MnSm/Ti catalyst were inhibited by the presence of CO in the mixed atmosphere. Furthermore, the presence of CO in the flue gas resulted in the formation of carbonates, bicarbonates, and bridging formate on the surface of the MnSm/Ti catalysts, which would cause a decrease in the content of Mn4+ and Oα on the surface of the catalyst surface. Introducing Co into MnSm/Ti catalyst could enhance the adsorption of NH3 by forming more Lewis acid sites over the MnSmCo/Ti catalyst. The contents of Mn4+ and Oα over MnSmCo/Ti catalyst were increased via the strong electronic interaction between Co ions and Mn ions. DFT calculations proved that the adsorption of CO over the catalyst was suppressed by the modification of Co with the change of the adsorption energy of CO from −167.25 kJ/mol to −53.82 kJ/mol. Additionally, the Co modification facilitated the decomposition of the carbonate formed over the catalyst with the energy barrier of related reactions decreasing from 214.67 kJ/mol to 24.45 kJ/mol, thus improving the CO tolerance of the catalyst.