High-Pressure Induced Continuous Structural Evolution of Kagome Antiferromagnet MgMn3(OH)6Cl2: A Structural Analogue to Quantum Spin Liquid Herbertsmithite.

MgMn3(OH)6Cl2 serves readily as the classical Heisenberg kagome antiferromagnet lattice spin frustration material, due to its similarity to herbertsmithite in composition and crystal structure. In this work, nanosheets of MgMn3(OH)6Cl2 are synthesized through a solid-phase reaction. Low-temperature magnetic measurements revealed two antiferromagnetic transitions, occurring at ∼8 and 55 K, respectively. Utilizing high-pressure synchrotron radiation X-ray diffraction techniques, the topological structural evolution of MgMn3(OH)6Cl2 under pressures up to 24.8 GPa was investigated. The sample undergoes a second-order structural phase transition from the rhombohedral phase to the monoclinic phase at pressures exceeding 7.8 GPa. Accompanying the disappearance of the Fano-like line shape in the high-pressure Raman spectra were the emergence of new Raman active modes and discontinuities in the variations of Raman shifts in the high-frequency region. The phase transition to a structure with lower symmetry was attributed to the pressure-induced enhancement of cooperative Jahn-Teller distortion, which is caused by the mutual substitution of Mn2+ ions from the kagome layer and Mg2+ ions from the triangular interlayer. High-pressure ultraviolet-visible absorption measurements support the structural evolution. This research provides a robust experimental approach and physical insights for further exploration of classical geometrical frustration materials with kagome lattice.

LncRNA NEAT-2 regulate the function of endothelial progenitor cells in experimental Sepsis model.

BACKGROUND: Sepsis is a life-threatening disease with a limited effectiveness and the potential mechanism remains unclear. LncRNA NEAT-2 is reported to be involved in the regulation of cardiovascular disease. This study aimed to investigate the function of NEAT-2 in sepsis. METHODS: We built sepsis animal model with Male Balb/C mice induced by cecal ligation and puncture (CLP). A total of 54 mice were randomly assigned into eight groups: sham operation group (n = 18), CLP group (n = 18), CLP plus si-control group (n = 3), CLP plus si-NEAT2 group (n = 3), CLP plus mimic control group (n = 3), CLP plus miR-320 group (n = 3), CLP plus normal saline group (n = 3), and normal control group (n = 3). The number of peripheral endothelial progenitor cells (EPCs), the expression level of NEAT-2 and miR-320 were detected during progression of sepsis, as well as the number of peripheral EPCs and level of TNF-α, IL-6, VEGF, ALT, AST and Cr. In addition, the function of EPCs was evaluated after NEAT-2 knockdown and miR-320 overexpression in vitro. RESULTS: The number of circulating EPCs increased significantly in sepsis. NEAT-2 expression was significantly increased in the progress of sepsis, accompanied with miR-320 downregulated. NEAT-2 knockdown and miR-320 overexpression attenuated hepatorenal function and increased cytokines in sepsis. Moreover, NEAT-2 knockdown and miR-320 overexpression decreased the proliferation, migration and angiogenesis of endothelial progenitor cells in vitro. CONCLUSIONS: LncRNA-NEAT2 regulated the number and function of endothelial progenitor cells via miR-320 in sepsis, which may contribute to the development of novel potential clinical therapy for sepsis.

Structural phase transformation of quantum spin liquid herbertsmithite via pressure induced enhancement of the cooperative Jahn-Teller effect and antisite disorder.

Herbertsmithite, Cu3Zn(OH)6Cl2, serves as one of the most promising candidates for quantum spin liquids with a perfect quantum kagome Heisenberg antiferromagnetic system. It can comprise an ideal model system for studying the compression response of the unique structure as well as exotic properties of kagome quantum spin liquid materials, which is of fundamental importance from both scientific and technological viewpoints. In this work, the structural evolution of herbertsmithite was investigated via in situ X-ray diffraction and Raman scattering techniques up to 30 GPa. The trigonal herbertsmithite structure transformed into a monoclinic clinoatacamite-like structure at 12.6 GPa. High pressure seems to act in a reverse way as Zn-doping for herbertsmithite, with the distortion degree of the system changing continuously. The occurrence of the displacive and reversible phase transition between the polymorphs is a consequence of the interplay between the external pressure and cooperative Jahn-Teller (JT) effect, aided by the presence of antisite mutual substitution of magnetic Cu2+ ions and nonmagnetic Zn2+ ions between the kagome layer and interlayer sites.

Pressure-Induced Modulation of Tin Selenide Properties: A Review.

Tin selenide (SnSe) holds great potential for abundant future applications, due to its exceptional properties and distinctive layered structure, which can be modified using a variety of techniques. One of the many tuning techniques is pressure manipulating using the diamond anvil cell (DAC), which is a very efficient in situ and reversible approach for modulating the structure and physical properties of SnSe. We briefly summarize the advantages and challenges of experimental study using DAC in this review, then introduce the recent progress and achievements of the pressure-induced structure and performance of SnSe, especially including the influence of pressure on its crystal structure and optical, electronic, and thermoelectric properties. The overall goal of the review is to better understand the mechanics underlying pressure-induced phase transitions and to offer suggestions for properly designing a structural pattern to achieve or enhanced novel properties.

Interplay between External High Pressure and Intrinsic Jahn-Teller Effect in the Compression Behavior of Clinoatacamite.

Clinoatacamite (γ-Cu2(OH)3Cl) possesses a geometrically frustrated kagome lattice for the S = 1/2 antiferromagnetic spin system. Thus, it is deemed as the mother compound of many promising quantum spin liquid materials. Here, we synthesized clinoatacamite consisting of homogeneous octahedron-like particles with an average size of 1-2 µm via a hydrothermal strategy. Clinoatacamite crystallizes in a monoclinic lattice composed of Jahn-Teller distorted Cu(OH)6 and Cu(OH)4Cl2 octahedrons. The bonding nature of clinoatacamite is characterized using Raman scattering and FTIR absorption spectroscopies, which reveal the existence of trimeric hydrogen bonds. The magnetic measurements indicate that at temperatures below about 6 K, the magnetic response of the prepared samples is dominated by weak ferromagnetic contributions. The compression behavior is investigated by in situ high-pressure synchrotron radiation X-ray diffraction and Raman scattering spectroscopy. An isostructural phase transition is observed at about 8.4 GPa, which is evidenced by the anomalies in the variation curves of the lattice parameters and Raman scattering frequencies with pressure. The occurrence of the isostructural phase transition is attributed to the competition and cooperation of the external pressure and intrinsic Jahn-Teller effect, together with the interplay of intrastructural hydrogen bonding.

Analysis of risk factors and prevention strategies for functional delayed gastric emptying in 1243 patients with distal gastric cancer.

BACKGROUND: Analysis of the risk factors associated with functional delayed gastric emptying after distal gastric cancer surgery to provide a basis for further reduction of the incidence of this complication. METHODS: Total of 1382 patients with distal gastric cancer from January 2016 to October 2018 were enrolled. Correlation analysis was performed in 53 patients with FDGE by logistic regression. Subgroup risk analysis was performed in 114 patients with preoperative pyloric obstruction. A Pearson Chi-square analysis was used to compare categorical variables between normal distribution groups. Meanwhile, a t test was used to compare continuous variables between groups. Odds ratio (OR) was used for comparison of the two groups, and it was summarized with its 95% confidence interval (CI) and p value using logistic regression. RESULT: In multivariable analysis, age (OR 1.081, 95% CI, 1.047-1.117), BMI (OR 1.233, 95% CI, 1.116-1.363), preoperative pyloric obstruction (OR 3.831, 95% CI, 1.829-8.023), smaller volume of residual stomach (OR 1.838, 95% CI, 1.325-6.080), and anastomosis in greater curvature perpendicular (OR 3.385, 95% CI, 1.632-7.019) and in greater curvature parallel (OR 2.375, 95% CI, 0.963-5.861) were independent risk factors of FDGE. In the preoperative pyloric obstruction group, higher BMI (OR 1.309, 95% CI, 1.086-1.579) and preoperative obstruction time (OR 1.054, 95% CI, 1.003-1.108) were independent risk factors of FDGE and preoperative gastrointestinal decompression (OR 0.231, 95% CI, 0.068-0.785) was independent protective factor of FDGE. CONCLUSION: Adequate gastrointestinal decompression should be performed before the operation to reduce the incidence of postoperative gastroparesis in patients with preoperative pyloric obstruction. We also could improve the surgical methods to reduce the occurrence of FDGE, such as controlling the size of the residual stomach, ensuring blood supply. Especially selecting an appropriate stapler and anastomosis during the anastomosis process, the occurrence of FDGE can be reduced.

Development and validation of a nomogram for preoperative prediction of lymph node metastasis in early gastric cancer.

BACKGROUND: The status of lymph nodes in early gastric cancer is critical to make further clinical treatment decision, but the prediction of lymph node metastasis remains difficult before operation. This study aimed to develop a nomogram that contained preoperative factors to predict lymph node metastasis in early gastric cancer patients. METHODS: This study analyzed the clinicopathologic features of 823 early gastric cancer patients who underwent gastrectomy retrospectively, among which 596 patients were recruited in the training cohort and 227 patients in the independent validation cohort. Significant risk factors in univariate analysis were further identified to be independent variables in multivariable logistic regression analysis, which were then incorporated in and presented with a nomogram. And internal and external validation curves were plotted to evaluate the discrimination of the nomogram. RESULTS: Totally, six independent predictors, including the tumor size, macroscopic features, histology differentiation, P53, carbohydrate antigen 19-9, and computed tomography-reported lymph node status, were enrolled in the nomogram. Both the internal validation in the training cohort and the external validation in the validation cohort showed the nomogram had good discriminations, with a C-index of 0.82 (95%CI, 0.78 to 0.86) and 0.77 (95%CI, 0.60 to 0.94) respectively. CONCLUSIONS: Our study developed a new nomogram which contained the most common and significant preoperative risk factors for lymph node metastasis in patients with early gastric cancer. The nomogram can identify early gastric cancer patients with the high probability of lymph node metastasis and help clinicians make more appropriate decisions in clinical practice.

Mutational spectrum and novel candidate genes in Chinese children with sporadic steroid-resistant nephrotic syndrome.

BACKGROUND: Approximately 10-20% of children with idiopathic nephrotic syndrome (NS) fail to respond to steroid therapy. NS is divided into steroid-sensitive NS (SSNS) and steroid-resistant NS (SRNS). Over 45 recessive and dominant genes have been found to be associated with SRNS and/or focal segmental glomerulosclerosis (FSGS). METHODS: Targeted sequencing of 339 candidate genes, expressed in glomerular filtration barrier or located in the signaling pathway of podocyte function, were sequenced by NGS in a cohort of total 89 Chinese Han children (29 sporadic SRNS, 33 sporadic SSNS, and 27 healthy). RESULTS: Two variants (WT1 p.R441X and NPHS2 p.G149V) were screened out as pathogenic mutations and 14 variants were likely pathogenic. Mutations of KIRREL2 (SRNS vs SSNS: 24.1% vs 3.0%, adjusted OR = 10.11, 95% CI: 1.56-198.66, P = 0.039) were significantly associated with the risk of pediatric sporadic SRNS. Besides, three pathogenic or likely pathogenic variants were identified in HP gene. CONCLUSION: Two pathogenic mutations and 14 likely pathogenic mutations were discovered through targeted sequencing of 339 candidate genes. Two genes, HP and KIRREL2, as candidate genes, were first proposed to be associated with the risk of pediatric sporadic SRNS.

A novel phloroglucinol and two new phenolic glycosides from Psidium littorale.

One novel phloroglucinol, psidosone A (1), and two new phenolic glycosides, psidoside A (2), and psidoside B (3), together with nine known phenol compounds (4-12), were isolated from the fruits of Psidium littorale Raddi. Their structures were elucidated using data obtained from MS, 1H and 13C NMR spectra, and correlation experiments (HMQC and HMBC), as well as by comparison with published data.

Oridonin protects the lung against hyperoxia-induced injury in a mouse model.

Hyperoxic acute lung injury (HALI) is caused by prolonged exposure to high oxygen partial pressure. This study was undertaken to investigate the protective effects of oridonin on HALI in a mouse model. Mice were randomly divided into three groups: the control group, HALI group and oridonin (ORI) group. HALI was induced by exposing mice to pure oxygen at 2.5 atmospheres absolute (ATA) for six hours in the HALI and ORI groups. In the ORI group, mice were intraperitoneally injected with ORI at 10 mg/kg twice daily after hyperoxic exposure. Animals were sacrificed 24 hours after the hyperoxia exposure, followed by bronchoalveolar lavage fluid (BALF). Lungs were then collected. Each lung was processed for HE staining and detection of wet-to-dry weight ratio. The lactate dehydrogenase (LDH) activity and protein content of BALF were determined, and the contents of malonaldehyde (MDA), glutathione (GSH), tumor necrosis factor alpha (TNF-?) and interleukin-10 (IL-10) in the lung were measured. Our results showed prolonged exposure to hyperoxia significantly damaged the lung, caused lung edema, increased MDA and TNF-?, and reduced GSH and IL-10 in the lung. However, post-exposure treatment with oridonin was able to improve lung pathology, attenuate lung edema, reduce MDA and TNF-?, and increase GSH and IL-10 in the lung. These findings suggest that oridonin can protect the lung against hyperoxia-induced injury in mice.

[Flavonoids from leaves of Psidum littorale].

We investigated the chemical constituents of the leaves of Psidum littorale, which include 16 flavonoids, including seven flavonols, six flavonoid glycosides and three flavonones. The compounds were isolated by silica gel column chromatography. Their structures were elucidated on the basis of spectral analysis and by comparison with published data. Seven flavonols were kaempferol (1), isorhamnetin (2), myricetin- 3,7,3'-trimethyl ether(3), laricitrin (4), quercetin (5), myricetin (6) and quercein-3,4'-dimethyl ether (7), six flavonoid glycosides were guaijaverin (8), hyperoside (9), 5,4'-dyhydroxy-3,7,5'-methoxyflavone-3'-O-ß-D- glucoside (10), laricitrin-3-O-xyloside (11), myricetin-3-O-α-L-rhamnopyranoside (12) and myricetin-3-O-ß-D- xyloside (13). Three flavonones were 4'-O-methyldihydroquercetin (14), dihydroapigenin (15) and ampelopsin 4'-O-ß-D-glucopyranoside (16). Compound 10 is a new chemical, compounds 2-4, 7, 10-16 were first isolated from this plant. (1)H NMR and (13)C NMR data of compound 11 were not reported in literature.

[Quality control of Maca (Lepidium meyenii)].

To control the quality of Maca, the quality standard was established in this study. According to the methods recorded in the Appendix of Chinese Pharmacopoeia (2010 Edition), the water, extract, total ash, acid insoluble substance, and heavy metals inspections in Lepidium meyenii were carried out. N-benzyl-9Z, 12Z-octadecadienamide in L. meyenii was identified by TLC, and it was determined by HPLC. The results showed that the N-benzyl-9Z, 12Z-octadecadienamide identification of TLC was a strong mark and specificity. In content determination experiment, the linearity of N-benzyl-9Z, 12Z-octadecadienamide was in the range of 0.01-2 microg (r = 0.9998), and the average recovery (n=9) was 99.27% (RSD 2.0%). The methods were simple, accurate, with good reproducibility. It is suitable for quality control L. meyenii.

Pressure-driven variations of hydrogen bonding energy in ammonium azide (NH4N3): IR absorption and Raman scattering studies.

In this study, high pressure infrared (IR) absorption and Raman scattering studies for ammonium azide (NH4N3) were carried out at room temperature up to 20 GPa and 22 GPa, respectively. For comparison and further assignment, the vibrational spectra at ambient conditions were calculated using CASTEP code, particularly for the far- and mid-IR modes. The recorded vibrational data consistently indicated a pressure-induced phase transition at 2.9 GPa. All observed vibrational modes maintained their identities at the high pressure phase, indicating that NH4N3 was still presented in the form of ammonium cations and azide anions linked by the hydrogen bond (N-H⋯N). Above 2.9 GPa, the relative magnitude of the torsional mode weakened and the N-H symmetric stretch displayed a redshift, indicating strengthened hydrogen bonding energy. The opposite effects were observed above 12 GPa, where the relative magnitude of the torsional mode strengthened and the N-H symmetric stretch reverted to a blueshift, indicating weakened hydrogen bonding energy. It can be concluded that the hydrogen bonding energy exhibited a weakening (0-2.9 GPa), strengthening (2.9-12 GPa), and then again weakening (12-22 GPa) phenomena with the increasing of compression. The hydrogen bonding energy changing with the increase of pressure can be ascribed to a phase transition at 2.9 GPa and a rotational or bending behavior of azide ions at 12 GPa.

Exogenous ethephon treatment on the biosynthesis and accumulation of astragaloside IV in Astragalus membranaceus Bge. Var. Mongholicus (Bge.) Hsiao.

BACKGROUND: Astragaloside IV is a main medicinal active ingredient in Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao, which is also the key biomarker of A. membranaceus quality. Ethylene has been well-documented to involve in secondary metabolites biosynthesis in plants. Nevertheless, how ethylene regulates astragaloside IV biosynthesis in A. membranaceus is still unclear. Therefore, in the present study different dosages and time-dependent exogenous application of ethephon (Eth) were employed to analyze astragaloside IV accumulation and its biosynthesis genes expression level in hydroponically A. membranaceus. RESULTS: Exogenous 200 µmol·L- 1Eth supply is most significantly increased astragaloside IV contents in A. membranaceus when compared with non-Eth supply. After 12 h 200 µmol·L- 1 Eth treatment, the astragaloside IV contents reaching the highest content at 3 d Eth treatment(P ≤ 0.05). Moreover, After Eth treatment, all detected key genes involved in astragaloside IV synthesis were significant decrease at 3rd day(P ≤ 0.05). However, SE displayed a significant increase at the 3rd day under Eth treatment(P ≤ 0.05). Under Eth treatment, the expression level of FPS, HMGR, IDI, SS, and CYP93E3 exhibited significant negative correlations with astragaloside IV content, while expression level of SE displayed a significant positive correlation. CONCLUSIONS: These findings suggest that exogenous Eth treatment can influence the synthesis of astragaloside IV by regulating the expression of FPS, HMGR, IDI, SS, CYP93E3 and SE. This study provides a theoretical basis for utilizing molecular strategies to enhance the quality of A. membranaceus.

Intervention of computer-assisted cognitive training combined with occupational therapy in people with mild cognitive impairment: a randomized controlled trial.

Objective: Investigate the impact of combined computerized cognitive training and occupational therapy on individuals with mild cognitive impairment (MCI). Methods: We randomly assigned 118 MCI patients into two groups: a combined intervention group (n = 37) and a control group (n = 81), the latter receiving standard nursing care. The intervention group additionally underwent 12 weeks of computerized cognitive training and occupational therapy. Blind assessors evaluated cognitive performance, anxiety, depression, and daily living activities before the intervention, post-intervention, and at a 3-month follow-up. Results: Repeated-measures analysis of variance showed that the sMoCA scores, HAMA scores, and ADL scores of the experimental group at T2 (post-intervention) and T3 (3-month follow-up) were higher than those of the control group, and the difference was statistically significant (p < 0.001, p < 0.001, p = 0.026). Conclusion: Computerized cognitive training combined with occupational therapy can improve patients' cognitive status, enhance their compliance with continuing care, and maintain their anxiety and self-care ability at a stable level. Clinical trial registration: https://www.chictr.org.cn/index.html, identifier ChiCTR2200065014.

Three-dimensional hidden phase probed by in-plane magnetotransport in kagome metal CsV3Sb5 thin flakes.

Transition metal compounds with kagome structure have been found to exhibit a variety of exotic structural, electronic, and magnetic orders. These orders are competing with energies very close to each other, resulting in complex phase transitions. Some of the phases are easily observable, such as the charge density wave (CDW) and the superconducting phase, while others are more challenging to identify and characterize. Here we present magneto-transport evidence of a new phase below ~ 35 K in the kagome topological metal CsV3Sb5 (CVS) thin flakes between the CDW and the superconducting transition temperatures. This phase is characterized by six-fold rotational symmetry in the in-plane magnetoresistance (MR) and is connected to the orbital current order in CVS. Furthermore, the phase is characterized by a large in-plane negative magnetoresistance, which suggests the existence of a three-dimensional, magnetic field-tunable orbital current ordered phase. Our results highlight the potential of magneto-transport to reveal the interactions between exotic quantum states of matter and to uncover the symmetry of such hidden phases.

What is the outcome of late-onset infected mesh removal after open tension-free inguinal hernioplasty: 3-year follow-up.

PURPOSE: Reports of mesh infections following open tension-free inguinal hernioplasty are gradually increasing. Recent research has focused on identifying and managing mesh infections. However, studies examining the long-term outcomes and quality of life following mesh removal for late-onset infections are few. This study aimed to analyze the short and long-term outcomes after maximal removal of the implanted mesh in patients with late-onset mesh infection after open tension-free inguinal hernioplasty. METHODS: Data of 105 patients who developed late-onset mesh infection after open tension-free inguinal hernioplasty and were admitted to our hospital from January 2014 to January 2019 were retrospectively analyzed. Patients were followed up by telephone or outpatient consultation for 3 years, focusing on hernia recurrence and mesh infection recurrence. Quality of life was assessed preoperatively and postoperatively using our developed scale; postoperative inguinal area pain was assessed using the visual analog score, and postoperative anxiety was assessed using the anxiety self-assessment scale. RESULTS: Of the 105 patients who experienced late-onset mesh infection following open inguinal hernioplasty, 100 underwent mesh plug repair. The mean follow-up time was 58 months, and 10.5% (95/105) of the patients were lost to follow-up. Recurrence of infection was observed in 28.6% of patients (2/7) who underwent partial mesh removal and in 3.4% of patients (3/88) who underwent complete mesh removal. One inguinal hernia recurred 12 months after mesh removal (1.0% recurrence rate). In the third year following surgery as compared to the preoperative period, there were significant improvements in quality of life. CONCLUSIONS: Hernia plugs may not be a good choice in tension-free inguinal hernia repair in view of the risk of late infections and fistulas. Remove all mesh at the time of the first operation for mesh infection. Hernia recurrence after late-onset infected mesh removal following open inguinal tension-free hernioplasty is rare. The post-operative quality of life, pain, and anxiety are gradually steadily improving.

A case of pulmonary infection with Prevotella melanogenica having the paving stone symptom.

Prevotella melanogenica is a typical organism present in the human oral cavity and female reproductive tract, which is responsible for causing periodontal disease and the inflammation of the female reproductive tract. The present report discusses the case of a young female patient who presented with cough and fever as the main clinical symptoms. Computed Tomography (CT) revealed multiple clusters of ground glass density shadows in both lungs, with network-like and paving stone-like changes. The alveolar lavage fluid was collected for next-generation sequencing, which revealed the presence of Prevotella melanogenica. The patient received treatments, CT revealed that the density of multiple flakes of ground glass density in both lungs was lower than the previously observed density. Prevotella melanogenica pneumonia is rare, and the paving stone symptom observed in CT is not specific. Therefore, the case reported here provides a novel perspective regarding the diagnosis of pneumonia.

Giant electrically tunable magnon transport anisotropy in a van der Waals antiferromagnetic insulator.

Anisotropy is a manifestation of lowered symmetry in material systems that have profound fundamental and technological implications. For van der Waals magnets, the two-dimensional (2D) nature greatly enhances the effect of in-plane anisotropy. However, electrical manipulation of such anisotropy as well as demonstration of possible applications remains elusive. In particular, in-situ electrical modulation of anisotropy in spin transport, vital for spintronics applications, has yet to be achieved. Here, we realized giant electrically tunable anisotropy in the transport of second harmonic thermal magnons (SHM) in van der Waals anti-ferromagnetic insulator CrPS4 with the application of modest gate current. Theoretical modeling found that 2D anisotropic spin Seebeck effect is the key to the electrical tunability. Making use of such large and tunable anisotropy, we demonstrated multi-bit read-only memories (ROMs) where information is inscribed by the anisotropy of magnon transport in CrPS4. Our result unveils the potential of anisotropic van der Waals magnons for information storage and processing.

Two-stage prediction model for postoperative delirium in patients in the intensive care unit after cardiac surgery.

OBJECTIVES: Postoperative delirium is a common severe complication in patients in the intensive care unit after cardiac surgery. We developed a two-stage prediction model and quantified the risk of developing postoperative delirium to assist in early prevention before and after surgery. METHODS: We conducted a prospective cohort study and consecutively recruited adult patients after cardiac surgery. The Confusion Assessment Method for patients in the intensive care unit was used to diagnose delirium 5 days postoperatively. The stage I model was constructed using patient demographics, health conditions and laboratory results obtained preoperatively, whereas the stage II model was built on both pre- and postoperative predictors. The model was validated internally using the bootstrap method and externally using data from an external cohort. RESULTS: The two-stage model was developed with 654 patients and was externally validated with 214 patients undergoing cardiac surgery. The stage I model contained 6 predictors, whereas the stage II model included 10 predictors. The stage I model had an area under the receiver operating characteristic curve of 0.76 (95% confidence interval: 0.68-0.81), and the stage II model's area under the receiver operating characteristic curve increased to 0.85 [95% confidence interval (CI): 0.81-0.89]. The external validation resulted in an area under the curve of 0.76 (95% CI: 0.67-0.86) for the stage I model and 0.78 (95% CI: 0.69-0.86) for the stage II model. CONCLUSIONS: The two-stage model assisted medical staff in identifying patients at high risk for postoperative delirium before and 24 h after cardiac surgery. This model showed good discriminative power and predictive accuracy and can be easily accessed in clinical settings. TRIAL REGISTRATION: The study was registered with the US National Institutes of Health ClinicalTrials.gov (NCT03704324; registered 11 October 2018).