Favorable Sites Research Articles

Mobile dislocation mediated Hall-Petch and inverse Hall-Petch behaviors in nanocrystalline Al-doped boron carbide

The Hall-Petch and inverse Hall-Petch behaviors in nanocrystalline ceramics are not well understood because dislocation activities, which are important in metals, are usually limited in these materials. In this study, we use molecular dynamics simulations with a machine-learning force field to investigate the shear deformation behaviors of nanocrystalline Al-doped boron carbide (n-B12-CAlC) as the grain size varies. We find a transition from the Hall-Petch to inverse Hall-Petch behavior in n-B12-CAlC when the grain size reaches its critical value of 6.09 nm, with a maximum shear strength of 14.93 GPa. Interestingly, mobile dislocation nucleated from grain boundaries (GBs) is activated in n-B12-CAlC due to the breakage of weakened C-Al chain bonds, which plays a significant role in its Hall-Petch behaviors. As the grain size decreases, the increasing GB regions homogenize the shear stress, which suppresses dislocation nucleation from GBs and strengthens the material, as observed in the conventional Hall-Petch relationship. However, with a further decrease in the grain size (< ∼ 6 nm), the increasing GB regions provide more favorable sites and a higher possibility for dislocation nucleation, reducing the shear strength and triggering a transition into the inverse Hall-Petch behavior. These findings shed light on deformation behaviors and mechanisms of nanocrystalline ceramics and provide an explanation for the transition from Hall-Petch to inverse Hall-Petch behaviors.

Treatment of Recurrent Orbital Rhabdomyosarcoma with Exenteration and HDR Brachytherapy in a Custom Mold

Rhabdomyosarcoma (RMS) is the most frequent cancer affecting the orbit in children. The orbit is classified as a favorable site for RMS as treatment with chemotherapy and radiation is effective. Local failure for patients with RMS of the orbit has ranged from 2-16% on IRS and COG protocols. In the event of local recurrence, survival is poor, and management is difficult. We report four patients with local recurrence of orbital RMS managed with orbital exenteration followed by high dose rate (HDR) brachytherapy. Four patients were treated from 2016-2022. HDR brachytherapy with Ir-192 was delivered in a custom mold of the orbit made after the orbital exenteration procedure. Brachytherapy was given in 6-7 twice daily (BID) fractions starting 1 week after the orbital exenteration. At the time of brachytherapy, patient ages were 3, 1, 7, and 7 years. Three patients had embryonal histology and underwent initial systemic therapy with ARST0331 regimen A. The fourth patient had alveolar, FOXO1 fusion positive RMS and was initially treated as per COG D9803 regimen A. All patients had received proton radiotherapy as part of initial treatment. Three received 50.40 Gy and one received 45 Gy. Patients developed biopsy-proven, recurrent disease an average of 56 weeks (range 38-77) after initial diagnosis. All patients received salvage chemotherapy before undergoing orbital exenteration at an average of 12 weeks after recurrence (range 5-16). Three patients received 30 Gy in 6 BID fractions, and one patient received 28 Gy in 7 fractions with HDR brachytherapy using an Ir-192 source. All four patients are alive without evidence of disease at an average of 27 months (range 6-70) from recurrence and 39 months (range 21-78) from initial diagnosis. All patients have acceptable orbit healing. Two patients have asymptomatic evidence of frontal lobe edema (and in one case possible necrosis) extending 1-2 cm above the orbit. This appears to be beyond the range of the brachytherapy dosimetry, but the combination of proton beam and brachytherapy are implicated. No other toxicities have occurred. Orbital RMS has a favorable prognosis, but local failure after initial combined modality therapy can be fatal. Options for successful local salvage are limited. Orbital exenteration with HDR brachytherapy in a custom mold is an effective and safe procedure for local control in these difficult cases.

High performance iridium loaded on natural halloysite nanotubes for CO-SCR reaction

Iridium nanocatalysts are ideal candidates for the selective catalytic reduction of NOx by CO (CO-SCR) in excess oxygen. Here, a high-performance Ir nanocatalyst supported on natural halloysite nanotubes (HNTs) was applied for the CO-SCR. The HNTs loaded with only 0.5 wt% Ir achieved 78 % NOx conversion at 250 °C in the presence of 5 % O2, which was the highest among catalysts with varied Ir loadings or reduction temperatures. It also possessed an excellent SO2 and H2O tolerance during longevity tests. An interesting SO2-enhanced CO-SCR long-term stability was observed, which was ascribed to the inhibitory effects of SO2 on the side reaction between CO and O2. The loading amount and the reduction temperature could modulate the size of Ir nanoparticles and the percent of Ir0, which were two key factors determining the CO-SCR activity. DRIFTS characterizations and DFT calculations coherently revealed the favorable adsorption sites of CO (top) and NO (hcp) on Ir nanoparticles. The Ir atoms served as a charge transfer bridge from the C atom of CO to the N atom of NO, leading to the enhanced breakage of N-O bonds. This work provides Ir/HNT as a promising CO-SCR material with high performance and robustness to tackle NOx pollution.

Exploring Conformational Landscapes and Cryptic Binding Pockets in Distinct Functional States of the SARS-CoV-2 Omicron BA.1 and BA.2 Trimers: Mutation-Induced Modulation of Protein Dynamics and Network-Guided Prediction of Variant-Specific Allosteric Binding Sites.

A significant body of experimental structures of SARS-CoV-2 spike trimers for the BA.1 and BA.2 variants revealed a considerable plasticity of the spike protein and the emergence of druggable binding pockets. Understanding the interplay of conformational dynamics changes induced by the Omicron variants and the identification of cryptic dynamic binding pockets in the S protein is of paramount importance as exploring broad-spectrum antiviral agents to combat the emerging variants is imperative. In the current study, we explore conformational landscapes and characterize the universe of binding pockets in multiple open and closed functional spike states of the BA.1 and BA.2 Omicron variants. By using a combination of atomistic simulations, a dynamics network analysis, and an allostery-guided network screening of binding pockets in the conformational ensembles of the BA.1 and BA.2 spike conformations, we identified all experimentally known allosteric sites and discovered significant variant-specific differences in the distribution of binding sites in the BA.1 and BA.2 trimers. This study provided a structural characterization of the predicted cryptic pockets and captured the experimentally known allosteric sites, revealing the critical role of conformational plasticity in modulating the distribution and cross-talk between functional binding sites. We found that mutational and dynamic changes in the BA.1 variant can induce the remodeling and stabilization of a known druggable pocket in the N-terminal domain, while this pocket is drastically altered and may no longer be available for ligand binding in the BA.2 variant. Our results predicted the experimentally known allosteric site in the receptor-binding domain that remains stable and ranks as the most favorable site in the conformational ensembles of the BA.2 variant but could become fragmented and less probable in BA.1 conformations. We also uncovered several cryptic pockets formed at the inter-domain and inter-protomer interface, including functional regions of the S2 subunit and stem helix region, which are consistent with the known role of pocket residues in modulating conformational transitions and antibody recognition. The results of this study are particularly significant for understanding the dynamic and network features of the universe of available binding pockets in spike proteins, as well as the effects of the Omicron-variant-specific modulation of preferential druggable pockets. The exploration of predicted druggable sites can present a new and previously underappreciated opportunity for therapeutic interventions for Omicron variants through the conformation-selective and variant-specific targeting of functional sites involved in allosteric changes.

Synergistic multi-adsorption of N2 on MoS2 supported single metal atoms: Enhancing electroreduction of nitrogen to ammonia

MoS2-supported transition metal single atom (TM/MoS2) is expected to exhibit good performance in N2 reduction reaction (NRR). Based on systematically investigations of the stability and potential electrocatalytic nitrogen reduction reaction (NRR) performance of 27 types of TM/MoS2, V(Nb, Ta)/MoS2 exhibit good structure stability, excellent N2 activity and high ammonia (NH3) selectivity. Three nitrogen molecules are effectively captured on V(Nb, Ta)/MoS2 and the multi-adsorption of nitrogen make Mo-top site energy favorable for all the *3N2–V(Nb, Ta)/MoS2 especially for *3N2–Nb/MoS2 the energy favorable sites shift from hollow site to Mo-top site. The NRR proceeds via distal pathway, along which the limiting potentials are calculated to be −0.55, −0.42, −0.34 V for V/MoS2, Nb/MoS2 and Ta/MoS2, respectively. The transformation of Nb/MoS2 and the multi-adsorption of *N2 make the *N2 more negatively charged and more effectively activated than single adsorbed *N2, meanwhile suppressing the production of hydrogen. This work also shows the coordination difference with and without reactants adsorption and the impact on catalytic performance, which raises the importance of considering the stability of intermediates along reaction paths during theoretical design of new catalysts.

Effect of Vacancy Defects and Hydroxyl on the Adsorption of Glycine on Mg(0001): A First-Principles Study

Glycine (Gly), as one of the fundamental components of biomolecules, plays a crucial role in functional biomolecular coatings. The presence of structural defects and hydroxyl-containing functional groups in magnesium (Mg) materials, which are commonly used as biomedical materials, significantly affects their biocompatibility and corrosion resistance performance. This study computationally investigates the influence of vacancy defects and hydroxyl groups on the adsorption behavior of Gly on Mg(0001) surfaces. All potential adsorption configurations are considered through first-principles calculations. The findings indicate that stronger chemisorption occurs when Gly is positioned at the edge of the groove, where the surface has a vacancy defect concentration of 1/3. Among the four adsorption locations, the fcc-hollow site is determined to be the most favorable adsorption site for hydroxyl. The adsorption energy of Gly on the Mg(0001) surface containing the hydroxyl (−1.11 eV) is 0.05 eV more than that of on the Mg(0001) surface (−1.16 eV). The adsorption energies, electronic properties, charge transfer, and stable configurations are calculated to evaluate the interaction mechanism between Gly and defective surfaces. Calculated results provide a comprehensive understanding of the interaction mechanism of biomolecules on defective Mg surfaces and also indicate the directions for future experimental research.

Modulation of electronic and magnetic properties of graphene-triangular h-BN hybrid through monovacancy: Carbon vacancy-BN size coupling

The effects of monovacancy on the stability, electronic and magnetic properties of the triangular h-BN embedded graphene nanosheet (G) were investigated by density functional theory (DFT) method. The interface is the energetically most favorable site for creating a vacancy in the GBN nanosheet. Defective GBN hybrids are either metallic or exhibit a small band gap energy ranging from 0.01 to 0.23 eV. The dangling bonds induced a localized magnetic moment ranging from 0.02 to 3 μB in the defective hybrid. The magnetic moment induced by the carbon vacancy in the G layout of the N-rich hybrid interestingly increases with island size. This coupling effect can be explained by the local charge imbalance between charge centers of opposite sign. We could not observe similar behavior in B- rich hybrids. Our results showed that the narrow bandgap and induced magnetic moment of the vacancy-defected GBN hybrid could be easily modulated and thus could be potential materials for spintronic /electronic applications.

Double-chain conjugated carbonyl polymer cathode for rechargeable magnesium batteries: Constructing active sites for reversible storage of bivalent magnesium cations

Rechargeable Mg batteries are advantageous substitutes for lithium-ion batteries in large-scale energy storage with low cost and high safety, but the lack of cathode materials is blocking the development. Organic polymers are promising Mg-storage materials, and the construction of suitable Mg-storage active sites is of great significance for the performance. In the present study, a double-chain conjugated carbonyl polymer is designed and investigated as cathode material of rechargeable Mg batteries. The double-chain structure builds favorable active sites for reversible storage of bivalent Mg2+ cation by means of immobilization of the two adjacent carbonyls. This double-chain polymer shows a higher Mg-storage capacity (194 mAg–1) than the corresponding single-chain polymer (116 mAg–1). The Mg-storage capacity of this double-chain polymer also exceeds the Li-storage capacity (106 mAg–1) significantly. A mechanism study demonstrates the reversible carbonyl enolization in Mg-storage reactions. A theoretical computation demonstrates the magnesiation structure has a higher HOMO and a lower LUMO energy level, as well as a smaller HOMO–LUMO gap. This is favorable for the Mg-storage reaction reversibility and stability of the magnesiation structure, thus improving the capacities and cycling stabilities. The principle revealed in the present study provides an important insight to design organic conjugated polymers with favorable Mg-storage active sites, which would assist the development of high-performance Mg-storage materials.

Electropolymerization of functionalized barium titanate reinforced polypyrrole composite coatings on nitinol alloy for biomedical applications

In the current study, the nitinol alloy (NiTi) was electrochemically coated with conductive polypyrrole (PPy) and polypyrrole/polydopamine functionalized barium titanate nanoparticles (PBT). The composite coatings were attained by adding different concentrations of PBT nanoparticles (1–10 wt%) to the electrochemical deposition bath. The results of transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), dynamic laser scanning (DLS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) confirmed the successful development of a polydopamine (PDA) layer on the surface of barium titanate nanoparticles (BT NPs) and their incorporation into PPy matrix composite coatings. The optimum concentration of PBT was beneficial for coating adhesion strength due to PDA bonding with PPy and metallic substrate via the catechol moieties. Electrochemical examinations demonstrated that PPy/5PBT coating revealed excellent corrosion protection in the Ringer medium. The PBT particles also reduced the overall conductivity of the PPy coating by about tenfold and significantly improved the mineralization of the composite coatings by providing favorable sites for Ca ion adsorption and subsequent hydroxyapatite (HA) formation reactions. The results of osteoblast cell attachment revealed that PBT had a promising effect on the cellular behavior of the composite-coated samples.

Good Vibrations Report on the DNA Quadruplex Binding of an Excited State Amplified Ruthenium Polypyridyl IR Probe.

The nitrile containing Ru(II)polypyridyl complex [Ru(phen)2(11,12-dCN-dppz)]2+ (1) is shown to act as a sensitive infrared probe of G-quadruplex (G4) structures. UV-visible absorption spectroscopy reveals enantiomer sensitive binding for the hybrid htel(K) and antiparallel htel(Na) G4s formed by the human telomer sequence d[AG3(TTAG3)3]. Time-resolved infrared (TRIR) of 1 upon 400 nm excitation indicates dominant interactions with the guanine bases in the case of Λ-1/htel(K), Δ-1/htel(K), and Λ-1/htel(Na) binding, whereas Δ-1/htel(Na) binding is associated with interactions with thymine and adenine bases in the loop. The intense nitrile transient at 2232 cm-1 undergoes a linear shift to lower frequency as the solution hydrogen bonding environment decreases in DMSO/water mixtures. This shift is used as a sensitive reporter of the nitrile environment within the binding pocket. The lifetime of 1 in D2O (ca. 100 ps) is found to increase upon DNA binding, and monitoring of the nitrile and ligand transients as well as the diagnostic DNA bleach bands shows that this increase is related to greater protection from the solvent environment. Molecular dynamics simulations together with binding energy calculations identify the most favorable binding site for each system, which are in excellent agreement with the observed TRIR solution study. This study shows the power of combining the environmental sensitivity of an infrared (IR) probe in its excited state with the TRIR DNA "site effect" to gain important information about the binding site of photoactive agents and points to the potential of such amplified IR probes as sensitive reporters of biological environments.

Wafer‐Scale Synthesis of Mixed‐Dimensional Heterostructures via Manipulating Platinization Conditions

Abstract2D van der Waals (vdW) hetero integration, which features exotic interplanar interactions derived from mixed‐dimensional heterostructures, is an emergent platform for implementing high‐performance electronics and broadband/wavelength‐tunable photodetectors. However, the production of large‐area 2D spatially homogeneous transition‐metal dichalcogenides (TMDs) and elucidation of the electrostatic dynamics governing the interlayer interactions are two paramount prerequisites for realizing practical 2D‐TMD‐heterostructure‐based photodetectors. Here, a wafer‐scale synthesis of mixed‐dimensional Pt–MoS2‐based vdW heterostructures is unprecedentedly demonstrated by manipulating the platinization conditions. The rationally designed platinization yields dimensionality‐tailored Pt, including Pt nanofilm, Pt nanoparticles, and Pt atoms, with MoS2 as host platform. From density functional theory calculations, this study insights that Mo vacancy sites on the MoS2 surface are thermo‐dynamically favorable sites for Pt with an adsorption energy of −2.25 eV, then Pt clusters are sequentially formed neighboring the specific Pt‐substituted position with a formation energy of 1.30 eV. Intensive microscopic and spectroscopic analyses reveal the structural, chemical, and electrical features, validating the proposed dynamics‐related mechanism. The dimensionality‐tailored vdW heterostructures exhibit outstanding optoelectrical properties with excellent photoresponsivity (2.04 mA W−1) and highly sensitive detectivity (9.82 × 106 cm Hz1/2 W−1).

Epitaxial growth of ultrathin gallium films on Cd(0001)

Growth and electronic properties of ultrathin Ga films on Cd(0001) are investigated by low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. It is found that Ga films exhibit the epitaxial growth with the pseudomorphic 1 × 1 lattice. The Ga islands deposited at 100 K show a ramified shape due to the suppressed edge diffusion and corner crossing. Furthermore, the majority of Ga islands reveal flat tops and a preferred height of three atomic layers, indicating the electronic growth at low temperature. Annealing to room temperature leads to not only the growth mode transition from electronic growth to conventional Stranski–Krastanov growth, but also the shape transition from ramified islands to smooth compact islands. Scanning tunneling spectroscopy (STS) measurements reveal that the Ga monolayer exhibits metallic behavior. DFT calculations indicate that all the interfacial Ga atoms occupy the energetically favorable hcp-hollow sites of the substrate. The charge density difference analysis demonstrates that the charge transfer from the Cd substrate to the Ga atoms is negligible, and there is weak interaction between Ga atoms and the Cd substrate. These results shall shed important light on fabrication of ultrathin Ga films on metal substrates with novel physical properties.

Variability of Radionuclide Sorption Efficiency on Muscovite Cleavage Planes

AbstractIn deep geological repositories for nuclear waste, the surrounding rock formation serves as an important barrier against radionuclide migration. Multiple potential host rocks contain phyllosilicates, which have shown high efficiency in radionuclide sorption. Recent experimental studies report a heterogeneous distribution of adsorbed radionuclides on nanotopographic mineral surfaces. In this study, the energetic differences of surface sorption sites available at nanotopographic structures such as steps, pits, and terraces are investigated. Eleven important surface sites are selected and the energies of ad‐ and desorption reactions are obtained from density functional theory calculations. The adsorption energies are then used for the parameterization of a kinetic Monte Carlo model simulating the distribution of adsorbed europium on a typical nanotopographic muscovite surface. On muscovite, silicon step sites are favorable for europium sorption and lead to an increased adsorption in regions with high step concentrations. Under identical chemical conditions, sorption on typical nanotopographic surfaces is increased by a factor of three compared to atomically flat surfaces. Desorption occurs preferentially at terrace sites, leading to an overall 2.5 times increased retention at nanotopographic structures. This study provides a mechanistic explanation for heterogeneous sorption on nanotopographic mineral surfaces due to the availability of energetically favorable sorption sites.

Crack tip dislocation activity in refractory high-entropy alloys

Dislocation activities play an important role in the deformation and failure of refractory high-entropy alloys (RHEAs). However, the impact of chemical short-range ordering (SRO) on dislocation activities at a crack tip in RHEAs remains unclear. Here, we investigate the effect of SRO on the dislocation nucleation, propagation, and reaction at a crack tip in a body-centered-cubic (BCC) MoTaTiWZr RHEA, using a combination of molecular dynamic simulations and Monte Carlo methods. Our results indicate that this RHEA is energetically favorable to form SRO, developing a pseudo-composite microstructure with low-energy clusters (LECs), medium-energy clusters (MECs), and high-energy clusters (HECs). The HECs at the crack tip are favorable sites for dislocation nucleation whereas the MECs surrounding the HECs function as a strong matrix to stabilize the weak HECs. At elevated temperatures, the HECs near the crack tip transform to severely distorted BCC and disordered structures, which can cause the breakup, absorption, and annihilation of emitted dislocations and nucleation of new dislocations. Our work reveals the interesting role of SRO in altering the dislocation activities at the crack tip of RHEAs and suggests alternative routes for designing superior RHEAs at both room and elevated temperatures.

Site selection in Switzerland: parallelization of implementer data collection and technical–political decision-making

Abstract. The ambition of the Swiss radioactive waste program is to store waste at the best-suited, safest site in Switzerland. In September 2022 the announcement of Nördlich Lägern as the best-suited site was a major milestone of this site selection process. The full documentation of the site selection and the safety assessment will be submitted with the general license application at the end of 2024. The total time of the site selection process from its formal initiation in 2008 until submission of the general license application will be 16 years. The three-phase site selection process consisted of (1) initial screening, (2) de-selection of less favourable sites and (3) identification of the best-suited region. The database was refined for each selection step, but detailed site characterization was restricted to the final phase. The selection criteria were kept unchanged in the entire process. Four groups were used: (1) properties of the host rock; (2) long-term evolution of the geological situation; (3) quality of the geological findings; (4) engineering feasibility. The requirements for the criteria were re-adjusted in each phase to honour the available data and to adopt the requirements to the increasing quality of the sites as less-suited regions were continuously screened out. Initial estimates for the duration of the site selection were in the range of 8–10 years. Soon it became clear that the technical work and the decision-making process for each phase would take additional time. To minimize phases of low activity, NAGRA started data collection campaigns for each step as soon as possible. This led to overlapping of regulator reviews and decision-making by the government for the previous step and data collection by NAGRA for the next step. Step-1 data collection started as soon as enough information about the process was available. This allowed the proposal of the initial selection of sites a few months later. Data collection for step 2 with seismic data reprocessing, outcrop work, investigations of third-party boreholes, regional seismic and geodetic monitoring and 2D fill-in lines began in 2009/10, well before the decision on step 1 by the federal government in 2011. This overlap allowed the proposal for the detailed sited investigations in 2014 to be prepared. Step 3 data collection with 3D seismic campaigns started in 2015. To minimize the delay between the 3D seismic investigations and the start of deep drillings, drill sites were planned on available 2D seismic information. In 2017 initial 3D seismic data became available, the drilling sequence was adopted accordingly and the first applications for the drill sites were handed in. The licensing of the drill sites was continuously adjusted together with the involved authorities. The decision of the federal government on completion of the second phase, confirming three sites for the third and last phase, was taken in 2018. The data collection in the third and final step was completed with the ninth deep borehole in early 2022. Close monitoring of the incoming data allowed the announcement of the best-suited site in September of the same year.

Microwave-Assisted Synthesis of Pd Nanoparticles into Wood Block (Pd@wood) as Efficient Catalyst for 4-Nitrophenol and Cr(VI) Reduction.

Palladium (Pd) nanoparticle catalysis has attracted increasing attention due to its efficient catalytic activity and its wide application in environmental protection and chemical synthesis. In this work, Pd nanoparticles (about 71 nm) were synthesized in aqueous solution by microwave-assisted thermal synthesis and immobilized in beech wood blocks as Pd@wood catalysts. The wood blocks were first hydrothermally treated with 10% NaOH solution to improve the internal structure and increase their porosity, thereby providing favorable attachment sites for the formed Pd nanoparticles. The stable deposition of Pd nanoparticle clusters on the internal channels of the wood blocks can be clearly observed. In addition, the catalytic performance of the prepared Pd@wood was investigated through two model reactions: the reduction of 4-nitrophenol and Cr(VI). The Pd@wood catalyst showed 95.4 g-1 s-1 M-1 of normalized rate constant knorm and 2.03 min-1 of the TOF, respectively. Furthermore, Pd nanoparticles are integrated into the internal structure of wood blocks by microwave-assisted thermal synthesis, which is an effective method for wood functionalization. It benefits metal nanoparticle catalysis in the synthesis of fine chemicals as well as in industrial wastewater treatment.

A Method for the Prediction of Favorable Sites on Faults That Adjust Outside-of-Source Hydrocarbon Accumulations to High-Slope Areas: A Case of the Zhaobei Fault in Qikou Sag, Bohai Bay Basin, Eastern China

In order to study the distribution pattern of hydrocarbons in the shallow layer of the slope area outside of the source in the hydrocarbon-bearing basin, we built a method to predict the favorable site of the fault that adjusts hydrocarbon to the shallow layer in the slope area outside of the source based on the investigation of the mechanism of hydrocarbon adjustment along a conduit fault to a shallow layer. The predicted favorable site is found to be the overlapping area of three sites: the locations of the sand carrier with a lateral supply of hydrocarbon, the transport sites of conduit faults, and the hydrocarbon leakage parts of overlying regional mudstone seal rock. We applied the method in a case study of the favorable sites of the Zhaobei Fault that adjust the hydrocarbon from the lower sub-member within the first member of Shahejie Formation (Es1L) to the shallow Guantao Formation in the Qikou Sag of Bohai Bay Basin. Our prediction shows that the favorable sites are mostly located in the middle part of the Zhaobei Fault with very limited distribution in the east, which are conducive to the oil and gas supplied by the underlying sand carrier in the Es1L Formation to convergence and accumulation in the shallow Guantao Formation. This result is consistent with the distribution of the hydrocarbon in the Guantao Formation located in the middle parts of the Zhaobei Fault, proving that this method is feasible for the prediction of the favorable sites of the fault that adjust hydrocarbon to the shallow layer in the slope area outside of source.

Metallogenic Model and Prospecting Progress of the Qiandongshan–Dongtangzi Large Pb-Zn Deposit, Fengtai Orefield, West Qinling Orogeny

The Qiandongshan–Dongtangzi large Pb-Zn deposit is located in the Fengxian–Taibai (abbr. Fengtai) polymetallic orefield. The ore bodies primarily occur within and around the contact surface between the limestone of the Gudaoling Formation and the phyllite of the Xinghongpu Formation, which are clearly controlled by anticline and specific lithohorizon. Magmatic rocks are well developed in the mining area, consisting mainly of granitoid plutons and mafic–felsic dikes. Previous metallogenic geochronology studies have yielded a narrow range of ages between 226 and 211 Ma, overlapped by the extensive magmatism during the Late Triassic period in this region. The ω(Co)/ω(Ni) ratio of pyrite in lead–zinc ore ranges from 4.44 to 15.57 (avg. 8.56), implying that its genesis is probably related to volcanic and magmatic-hydrothermal fluids. The δD and δ18O values (ranging from −94.2‰ to −82‰, and 18.89‰ to 20.72‰, respectively,) of the ore-bearing quartz indicate that the fluids were perhaps derived from a magmatic source. The δ34S values of ore-related sulfides display a relatively narrow range of 4.29‰ to 9.63‰ and less than 10‰, resembling those of magmatic-hydrothermal origin Pb-Zn deposits. The Pb isotopic composition of the sulfides from the Qiandongshan–Dongtangzi Pb-Zn deposit (with 206Pb/204Pb ratios of 18.06 to 18.14, the 207Pb/204Pb ratios of 15.61 to 15.71, and 208Pb/204Pb ratios of 38.15 to 38.50) is similar to that of the Late Triassic Xiba granite pluton, suggesting that they share the same Pb source. The contents of W, Mo, As, Sb, Hg, Bi, Cd, and other elements associated with magmatic-hydrothermal fluids are high in lead–zinc ores, and the contents of Sn, W, Co, and Ni are also enriched in sphalerite. The contents of trace elements and rare earth elements in the ore are similar to those in the Xiba granite pluton, and they maybe propose a magmatic-hydrothermal origin as well. As a result of this information, the Qiandongshan–Dongtangzi large Pb-Zn deposit may be classified as a magmatic hydrothermal stratabound type, with the Si/Ca contact area being the ore-forming structural plane. Thus, a mineralization model has been proposed based on a comparative analysis of the geological and geochemical properties of the lead–zinc deposit in the Fengtai orefield. It is considered that the secondary anticlines developed on both wings of the Qiandongshan–Dongtangzi composite anticline are the favorable sites for Pb-Zn deposition. Accordingly, the Si/Ca plane and secondary anticline are the major ore-controlling factors and prospecting targets. The verification project was first set up on the north wing of the composite anticline, and thick lead–zinc ore bodies were found in all verification boreholes, accumulating successful experience for deep exploration of lead–zinc deposits in this region.

Temperature effect on sulphur adsorption on iron surface: A molecular dynamics simulations study

The effect of temperature on the adsorption of a sulphur atom on the Fe(110) surface has been investigated using molecular dynamics simulations at a temperature of 353[Formula: see text]K, 373[Formula: see text]K and 398[Formula: see text]K. The most favorable adsorption site for a sulphur atom on the Fe(110) is found at a hollow site. The perpendicular height of the sulphur atom position is 4.017[Formula: see text]Å above the Fe surface at a temperature of 398[Formula: see text]K. The Fe–S bonding strength was affected by temperature, it becomes weaker with increasing temperature. The adsorption energy is calculated to be −6.640[Formula: see text]eV, −6.579[Formula: see text]eV and −1.841[Formula: see text]eV for the system at a temperature of 353[Formula: see text]K, 373[Formula: see text]K and 398[Formula: see text]K, respectively. This condition is confirmed by experimental results where the corrosion rate of the samples began to appear at 353[Formula: see text]K, with darker physical characteristics of the corrosion.

Extreme Limb Salvage: The Thin SCIP Flap for Distal Amputation Coverage in Highly Comorbid Patients.

Limb length preservation is correlated with overall survival. Successful free flap coverage of forefoot, midfoot, and hindfoot amputations can prevent more proximal below-knee amputations but is challenging in patients with multiple comorbidities. The thin superficial circumflex iliac artery perforator (SCIP) flap is well-suited for these patients, as it provides thin, pliable tissue from a favorable donor site. A retrospective review of all patients with distal amputations requiring coverage with a thin SCIP flap between 2016 to 2022 was performed. Patient demographics, amputation levels, and wound characteristics in addition to flap and microsurgery details were analyzed. The primary outcome was limb salvage. Secondary outcomes included partial flap necrosis, flap revision rate, and additional postoperative complications. Thirty-two patients (mean age, 57.3 years) underwent reconstruction of forefoot, midfoot, and hindfoot amputations with thin SCIP flaps (mean follow-up, 36 months). Twenty-eight patients (87.5%) had diabetes, 27 (84.4%) had peripheral artery disease, and 15 (46.9%) were dialysis-dependent. Average flap size was 59.5 cm 2 and average flap thickness was 5.7 mm. Successful limb salvage was achieved in 27 patients (84.3%). Three cases (9.4%) had total flap loss. Twenty-one flaps (65.6%) had partial necrosis, of which 12 (57.1%) healed with conservative management and 7 (33.3 %) healed after late revision. The thin SCIP flap is a useful option for coverage of distal pedal amputations in patients with significant comorbidities. Despite higher rates of partial flap necrosis, free flap reconstruction allowed for high rates of limb salvage in a challenging patient population. Therapeutic, IV.