Key for Hexagonal Diamond Formation: Theoretical and Experimental Study.

Hexagonal diamond (HD) was reported 60 years ago and has attracted extensive attention owing to its ultrahigh theoretical hardness, 58% superior to its cubic counterpart. However, to date, synthesizing pure HD under high-pressure and high-temperature (HPHT) remains unsuccessful due to the limitations of understanding the formation mechanism. In this work, employing a systematic molecular dynamics simulation, we directly observe the graphite-to-HD transition in a nucleation-growth mechanism.

Concurrent Pressure-Induced Superconductivity and Photoconductivity Transitions in PbSeTe.

Concurrent superconductivity and negative photoconductivity (NPC) are rarely observed. Here, the discovery in PbSeTe of superconductivity and photoconductivity transitions between positive photoconductivity (PPC) and NPC during compression is reported to ≈40 GPa and subsequent decompression, which are also accompanied by reversible structure transitions (3D Fm m ⇌ 2D Pnma ⇌ 3D Pm m). Superconductivity with a maximum T of ≈6.

Two Novel and Two Recurrent Variants of the ADAR1 Gene in Three Chinese Families with Dyschromatosis Symmetrica Hereditaria.

Purpose: Dyschromatosis symmetrica hereditaria (DSH) is a rare autosomal dominant inherited pigmentary dermatosis. The gene responsible for DSH has been identified as adenosine deaminase acting on RNA1 (). This study aimed to identify the causative variants in the gene in three Chinese families with DSH.

Re-evaluating the necessity of routine laboratory monitoring during isotretinoin therapy for acne.

In this letter, we discuss the topic of necessity of routine laboratory monitoring during isotretinoin treatment for acne. According to Park and colleagues, it is advisable to monitor the levels of triglycerides, alanine aminotransferase, and aspartate aminotransferase every 5 to 6 months. Additionally, the levels of total cholesterol and low-density lipoprotein should be checked within the first two months of treatment.

The Transformation Mechanism of Graphite to Hexagonal Diamond under Shock Conditions.

The formation of a hexagonal diamond represents one of the most intriguing questions in materials science. Under shock conditions, the graphite basal plane tends to slide and pucker to form diamond. However, how the shock strength determines the phase selectivity remains unclear.

A novel sp carbon allotrope with 4+5+6+7+8 odd-even ring.

In this study, we report a novel monoclinic phase of carbon that contains 4+5+6+7+8 member rings in 2/ symmetry, identified by applying the stochastic surface walking method combined with high dimensional neural network potentials. We demonstrate that this phase possesses lower energy than graphite above 21.5 GPa.

Enhanced Hydrogen Evolution Catalysis of Pentlandite due to the Increases in Coordination Number and Sulfur Vacancy during Cubic-Hexagonal Phase Transition.

The search for new phases is an important direction in materials science. The phase transition of sulfides results in significant changes in catalytic performance, such as MoS and WS. Cubic pentlandite [cPn, (Fe, Ni)S] can be a functional material in batteries, solar cells, and catalytic fields.

Inhibition of defect-induced α-to-δ phase transition for efficient and stable formamidinium perovskite solar cells.

Defects passivation is widely devoted to improving the performance of formamidinium lead triiodide perovskite solar cells; however, the effect of various defects on the α-phase stability is still unclear. Here, using density functional theory, we first reveal the degradation pathway of the formamidinium lead triiodide perovskite from α to δ phase and investigate the effect of various defects on the energy barrier of phase transition. The simulation results predict that iodine vacancies are most likely to trigger the degradation, since they obviously reduce the energy barrier of α-to-δ phase transition and have the lowest formation energies at the perovskite surface.

Silica-water superstructure and one-dimensional superionic conduit in Earth's mantle.

Water in Earth's deep interior is predicted to be hydroxyl (OH) stored in nominally anhydrous minerals, profoundly modulating both structure and dynamics of Earth's mantle. Here, we use a high-dimensional neuro-network potential and machine learning algorithm to investigate the weight percent water incorporation in stishovite, a main constituent of the subducted oceanic crust. We found that stishovite and water prefer forming medium- to long-range ordered superstructures, featuring one-dimensional (1D) water channels.

Interstitial Hydrogen Atom to Boost Intrinsic Catalytic Activity of Tungsten Oxide for Hydrogen Evolution Reaction.

Tungsten oxide (WO ) is an appealing electrocatalyst for the hydrogen evolution reaction (HER) owing to its cost-effectiveness and structural adjustability. However, the WO electrocatalyst displays undesirable intrinsic activity for the HER, which originates from the strong hydrogen adsorption energy. Herein, for effective defect engineering, a hydrogen atom inserted into the interstitial lattice site of tungsten oxide (H WO ) is proposed to enhance the catalytic activity by adjusting the surface electronic structure and weakening the hydrogen adsorption energy.

Topological Ordering of Memory Glass on Extended Length Scales.

Identifying ordering in non-crystalline solids has been a focus of natural science since the publication of Zachariasen's random network theory in 1932, but it still remains as a great challenge of the century. Literature shows that the hierarchical structures, from the short-range order of first-shell polyhedra to the long-range order of translational periodicity, may survive after amorphization. Here, in a piece of AlPO, or berlinite, we combine X-ray diffraction and stochastic free-energy surface simulations to study its phase transition and structural ordering under pressure.

Negative linear compressibility in Se at ultra-high pressure above 120 GPa.

A series of synchrotron X-ray diffraction (XRD) measurements were carried out, combined with first-principles calculations, to study structural phase transitions of selenium at high pressures and room temperature. Several phase transitions were observed, among which an isostructural phase transition was found at around 120 GPa for the first time. Evolved from the rhombohedral (space group 3 ) structure (Se-V), the new phase (Se-V') exhibited an interesting increase of lattice parameter at pressures from 120 to 148 GPa, known as negative linear compressibility (NLC).

Pressure tuned incommensurability and guest structure transition in compressed scandium from machine learning atomic simulation.

Scandium (Sc) is the lightest non-main-group element and transforms to a host-guest (H-G) incommensurate structure under gigapascal (GPa) pressures. While the host structure is stable over a wide pressure range, the guest structure may exist in multiple forms, featuring different incommensurate ratios, and mixing up to generate long-range "disordered" guest structures. Here, we employed the recently developed global neural network (g-NN) potential and the stochastic surface walking (SSW) global optimization algorithm to explore the global potential energy surface of Sc under various pressures.

Confronting the Air Instability of Cesium Tin Halide Perovskites by Metal Ion Incorporation.

Tin halide perovskite's potential as a photovoltaic absorber has not been fully realized to date, largely due to its instability in ambient air. Here, we demonstrate by both experiments and simulations that the air instability of black-phase cesium tin iodide perovskite (γ-CsSnI) could be greatly lessened by a controlled incorporation of bismuth (Bi) ions into the crystal lattice. Hall effect measurements on films of γ-CsSnI suggest the unwanted formation of a tin vacancy and p-type self-doping can be effectively suppressed by the Bi incorporation.

Unraveling the structural transition mechanism of room-temperature compressed graphite carbon.

The discovery of graphite transition to transparent and superhard carbons under room-temperature compression (Takehiko, , , 1991, , 1542 and Mao, , , 2003, , 425) launched decades of intensive research into carbon's structural polymorphism and relative phase transition mechanisms. Although many possible carbon allotropes have been proposed, experimental observations and their transition mechanisms are far from conclusive. Three longstanding issues are: (i) the speculative structures inferred by amorphous-like XRD peaks, (ii) sp and sp bonding mixing, and (iii) the controversies of transition reversibility.

Assessing the impact of different distal ureter management techniques during radical nephroureterectomy for primary upper urinary tract urothelial carcinoma on oncological outcomes: A systematic review and meta-analysis.

Objectives: To assess the oncological outcomes of several distal ureter management techniques in patients administered with radical nephroureterectomy (RNU) for primary upper urinary tract urothelial carcinoma (UTUC).

Methods: A systematic search of PubMed, EMBASE, and the Cochrane Library was conducted to identify studies comparing outcomes following RNU under various surgical methods for bladder cuff management. Standard cumulative analyses of hazard ratios (HRs) with 95% confidence intervals (CIs) were performed using Review Manager (5.

Technical Modification of the Terminal Ureter During Total Transperitoneal Laparoscopic Nephroureterectomy for Upper Urinary Tract Urothelial Carcinoma.

Upper tract urothelial carcinoma (UTUC) accounts for 5%-10% of all urothelial tumors. Radical nephroureterectomy is the standard treatment procedure. At present, different choices still exist for treating the ureteral end during laparoscopic ureteral bladder sleeve resection.

Electrides with Dinitrogen Ligands.

Electrides are a class of materials which contain excess electrons occupying the cavities in the crystal and playing the role of anions. To achieve electron-rich conditions, it usually requires a positive total formal charge in electride materials. However, the assignment of charges relies on a detailed analysis on chemical bonding.

Structure-Controlled Oxygen Concentration in FeO and FeO.

Solid-solid reaction, particularly in the Fe-O binary system, has been extensively studied in the past decades because of its various applications in chemistry and materials and earth sciences. The recently synthesized pyrite-FeO at high pressure suggested a novel oxygen-rich stoichiometry that extends the achievable O-Fe ratio in iron oxides by 33%. Although FeO was synthesized from FeO and O, the underlying solid reaction mechanism remains unclear.

ROY revisited, again: the eighth solved structure.

X-ray powder diffraction and crystal structure prediction (CSP) algorithms were used in synergy to establish the crystal structure of the eighth polymorph of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY), form R05. R05 crystallizes in the monoclinic space group P21 with lattice parameters a = 11.479(4) Å, b = 11.

Photoselective Vaporesection of the Prostate via an End-firing Lithium Triborate Crystal Laser.

The occurrence of lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia (BPH) is a common problem with a high incidence in the aging male population. Although it is not a life-threatening disease, BPH causes problems that seriously impact the quality of life. Here, we introduce a new technique called photoselective vaporesection of the prostate (PVRP) in treating BPH, which can be seen as a variation of photoselective vaporization of the prostate (PVP).

Hydrogen-Bond Symmetrization Breakdown and Dehydrogenation Mechanism of FeOH at High Pressure.

The cycling of hydrogen plays an important role in the geochemical evolution of our planet. Under high-pressure conditions, asymmetric hydroxyl bonds tend to form a symmetric O-H-O configuration in which H is positioned at the center of two O atoms. The symmetrization of O-H bonds improves their thermal stability and as such, water-bearing minerals can be present deeper in the Earth's lower mantle.

Fractal MTW Zeolite Crystals: Hidden Dimensions in Nanoporous Materials.

Screw dislocation structures in crystals are an origin of symmetry breaking in a wide range of dense-phase crystals. Preparation of such analogous structures in framework-phase crystals is of great importance in zeolites but is still a challenge. On the basis of crystal-structure solving and model building, it was found that the two specific intergrowths in MTW zeolite produce this complex fractal and spiral structure.