Outcomes of Patients With Cancer With Myocardial Infarction-Associated Cardiogenic Shock Managed With Mechanical Circulatory Support.

Background: Cardiogenic shock (CS) is the leading cause of death among patients with acute myocardial infarction (AMI) and is managed with temporary mechanical circulatory support (tMCS) in advanced cases. Patients with cancer are at high risk of AMI and CS. However, outcomes of patients with cancer and AMI-CS managed with tMCS have not been rigorously studied. Methods: Adult patients with AMI-CS managed with tMCS from 2006 to 2018 with and without cancer were identified using the National Inpatient Sample. Propensity score matching (PSM) was performed for variables associated with cancer. Primary outcome was in-hospital death, and secondary outcomes were major bleeding and thrombotic complications. Results: After PSM, 1287 patients with cancer were matched with 12,870 patients without cancer. There was an increasing temporal trend for prevalence of cancer among patients admitted with AMI-CS managed with tMCS (P trend < .001). After PSM, there was no difference in in-hospital death (odds ratio [OR], 1.00; 95% CI, 0.88-1.13) or thrombotic complications (OR, 1.10; 95% CI, 0.91-1.34) between patients with and without cancer. Patients with cancer had a higher risk of major bleeding (OR, 1.29; 95% CI, 1.15-1.46). Conclusions: Among patients with AMI-CS managed with tMCS, cancer is becoming increasingly frequent and associated with increased risk of major bleeding, although there was no difference in in-hospital death. Further studies are needed to further characterize outcomes, and inclusion of patients with cancer in trials of tMCS is needed.

Encapsulating Nickel-Iron Alloy Nanoparticles in a Polysilazane-Derived Microporous Si-C-O-N-Based Support to Stimulate Superior OER Activity.

The in situ confinement of nickel (Ni)-iron (Fe) nanoparticles (NPs) in a polymer-derived microporous silicon carboxynitride (Si-C-O-N)-based support is investigated to stimulate superior oxygen evolution reaction (OER) activity in an alkaline media. Firstly, we consider a commercial polysilazane (PSZ) and Ni and Fe chlorides to be mixed in N,N-dimethylformamide (DMF) and deliver after overnight solvent reflux a series of Ni-Fe : organosilicon coordination polymers. The latter are then heat-treated at 500 °C in flowing argon to form the title compounds. By considering a Ni : Fe ratio of 1.5, face centred cubic (fcc) NixFey alloy NPs with a size of 15-30 nm are in situ generated in a porous Si-C-O-N-based matrix displaying a specific surface area (SSA) as high as 237 m2 ⋅ g-1. Hence, encapsulated NPs are rendered accessible to promote electrocatalytic water oxidation. An OER overpotential as low as 315 mV at 10 mA ⋅ cm-2 is measured. This high catalytic performance (considering that the metal mass loading is as low as 0.24 mg cm-2) is rather stable as observed after an activation step; thus, validating our synthesis approach. This is clearly attributed to both the strong NP-matrix interaction and the confinement effect of the matrix as highlighted through post mortem microscopy observations.

Novel Lewis Acid-Base Interactions in Polymer-Derived Sodium-Doped Amorphous Si-B-N Ceramic: Towards Main-Group-Mediated Hydrogen Activation.

Interest is growing in transition metal-free compounds for small molecule activation and catalysis. We discuss the opportunities arising from synthesizing sodium-doped amorphous silicon-boron-nitride (Na-doped a-SiBN). Na+ cations and 3-fold coordinated BIII moieties were incorporated into an amorphous silicon nitride network via chemical modification of a polysilazane followed by pyrolysis in ammonia at 1000 °C. Emphasis is placed on the mechanisms of hydrogen (H2) activation within Na-doped a-SiBN structure. This material design approach allows the homogeneous distribution of Na+ and BIII moieties surrounded by SiN4 units contributing to the transformation of the BIII moieties into 4-fold coordinated geometry upon encountering H2, potentially serving as frustrated Lewis acid (FLA) sites. Exposure to H2 induced formation of frustrated Lewis base (FLB) N-= sites with Na+ as a charge-compensating cation, resulting in the in situ formation of a frustrated Lewis pair (FLP) motif (≡BFLA···Hδ-···Hδ+···:N-(Na+)=). Reversible H2 adsorption-desorption behavior with high activation energy for H2 desorption (124 kJ mol-1) suggested the H2 chemisorption on Na-doped a-SiBN. These findings highlight a future landscape full of possibilities within our reach, where we anticipate main-group-mediated small molecule activation will have an important impact on the design of more efficient catalytic processes and the discovery of new catalytic transformations.

Physiology-Guided Resuscitation: Monitoring and Augmenting Perfusion during Cardiopulmonary Arrest.

Given the high morbidity and mortality associated with cardiopulmonary arrest, there have been multiple trials aimed at better monitoring and augmenting coronary, cerebral, and systemic perfusion. This article aims to elucidate these interventions, first by detailing the physiology of cardiopulmonary resuscitation and the available tools for managing cardiopulmonary arrest, followed by an in-depth examination of the newest advances in the monitoring and delivery of advanced cardiac life support.

Downshift of the Ni d band center over Ni nanoparticles in situ confined within an amorphous silicon nitride matrix.

Herein, nanocomposites made of Ni nanoparticles in situ distributed in an amorphous silicon nitride (Ni/a-Si3N4) matrix, on the one hand, and within an amorphous silicon dioxide (Ni/a-SiO2) matrix, on the other hand, were synthesized from the same Ni-modified polysilazane precursor. In both compounds, the Ni/Si atomic ratio (0.06-0.07), average Ni nanocrystallite size (7.0-7.6 nm) and micro/mesoporosity of the matrix were rigorously fixed. Hydrogen (H2)-temperature-programmed desorption (TPD) profile analysis revealed that the activation energy for H2 desorption at about 100-130 °C evaluated for the Ni/a-Si3N4 sample (47.4 kJ mol-1) was lower than that for the Ni/a-SiO2 sample (68.0 kJ mol-1). Mechanistic study with X-ray photoelectron spectroscopy (XPS) analysis and density functional theory (DFT) calculations revealed that, at Ni nanoparticle/matrix heterointerfaces, Ni becomes more covalently bonded to N atoms in the a-Si3N4 matrix compared to O atoms in the a-SiO2 matrix. Therefore, based on experimental and theoretical studies, we elucidated that nickel-nitrogen (Ni-N) interactions at the heterointerface lead to remarkable Ni d band broadening and downshifting of the d band center relative to those generated by Ni-oxygen (Ni-O) interactions at the heterointerface. This facilitates H2 desorption, as experimentally observed in the Ni/a-Si3N4 sample.

Relationship between the mixed venous-to-arterial carbon dioxide gradient and the cardiac index in acute pulmonary embolism.

AIMS: Among patients with acute pulmonary embolism (PE) undergoing mechanical thrombectomy, the cardiac index (CI) is frequently reduced even among those without a clinically apparent shock. The purpose of this study is to describe the mixed venous-to-arterial carbon dioxide gradient (CO2 gap), a surrogate of perfusion adequacy, among patients with acute PE undergoing mechanical thrombectomy. METHODS AND RESULTS: This was a single-centre retrospective study of consecutive patients with PE undergoing mechanical thrombectomy and simultaneous pulmonary artery catheterization over a 3-year period. Of 107 patients, 97 had simultaneous mixed venous and arterial blood gas measurements available. The CO2 gap was elevated (>6 mmHg) in 51% of the cohort and in 49% of patients with intermediate-risk PE. A reduced CI (≤2.2 L/min/m2) was associated with an increased odds [odds ratio = 7.9; 95% confidence interval (CI) 3.49-18.1, P < 0.001] for an elevated CO2 gap. There was an inverse relationship between the CI and the CO2 gap. For every 1 L/min/m2 decrease in the CI, the CO2 gap increased by 1.3 mmHg (P = 0.001). Among patients with an elevated baseline CO2 gap >6 mmHg, thrombectomy improved the CO2 gap, CI, and mixed venous oxygen saturation. When the CO2 gap was dichotomized above and below 6, there was no difference in the in-hospital mortality rate (9 vs. 0%; P = 0.10; hazard ratio: 1.24; 95% CI 0.97-1.60; P = 0.085). CONCLUSION: Among patients with acute PE undergoing mechanical thrombectomy, the CO2 gap is abnormal in nearly 50% of patients and inversely related to the CI. Further studies should examine the relationship between markers of perfusion and outcomes in this population to refine risk stratification.

Development and external validation of a dynamic risk score for early prediction of cardiogenic shock in cardiac intensive care units using machine learning.

AIMS: Myocardial infarction and heart failure are major cardiovascular diseases that affect millions of people in the USA with morbidity and mortality being highest among patients who develop cardiogenic shock. Early recognition of cardiogenic shock allows prompt implementation of treatment measures. Our objective is to develop a new dynamic risk score, called CShock, to improve early detection of cardiogenic shock in the cardiac intensive care unit (ICU). METHODS AND RESULTS: We developed and externally validated a deep learning-based risk stratification tool, called CShock, for patients admitted into the cardiac ICU with acute decompensated heart failure and/or myocardial infarction to predict the onset of cardiogenic shock. We prepared a cardiac ICU dataset using the Medical Information Mart for Intensive Care-III database by annotating with physician-adjudicated outcomes. This dataset which consisted of 1500 patients with 204 having cardiogenic/mixed shock was then used to train CShock. The features used to train the model for CShock included patient demographics, cardiac ICU admission diagnoses, routinely measured laboratory values and vital signs, and relevant features manually extracted from echocardiogram and left heart catheterization reports. We externally validated the risk model on the New York University (NYU) Langone Health cardiac ICU database which was also annotated with physician-adjudicated outcomes. The external validation cohort consisted of 131 patients with 25 patients experiencing cardiogenic/mixed shock. CShock achieved an area under the receiver operator characteristic curve (AUROC) of 0.821 (95% CI 0.792-0.850). CShock was externally validated in the more contemporary NYU cohort and achieved an AUROC of 0.800 (95% CI 0.717-0.884), demonstrating its generalizability in other cardiac ICUs. Having an elevated heart rate is most predictive of cardiogenic shock development based on Shapley values. The other top 10 predictors are having an admission diagnosis of myocardial infarction with ST-segment elevation, having an admission diagnosis of acute decompensated heart failure, Braden Scale, Glasgow Coma Scale, blood urea nitrogen, systolic blood pressure, serum chloride, serum sodium, and arterial blood pH. CONCLUSION: The novel CShock score has the potential to provide automated detection and early warning for cardiogenic shock and improve the outcomes for millions of patients who suffer from myocardial infarction and heart failure.

Echocardiography in the Recognition and Management of Mechanical Complications of Acute Myocardial Infarction.

PURPOSE OF REVIEW: Although rare, the development of mechanical complications following an acute myocardial infarction is associated with a high morbidity and mortality. Here, we review the clinical features, diagnostic strategy, and treatment options for each of the mechanical complications, with a focus on the role of echocardiography. RECENT FINDINGS: The growth of percutaneous structural interventions worldwide has given rise to new non-surgical options for management of mechanical complications. As such, select patients may benefit from a novel use of these established treatment methods. A thorough understanding of the two-dimensional, three-dimensional, color Doppler, and spectral Doppler findings for each mechanical complication is essential in recognizing major causes of hemodynamic decompensation after an acute myocardial infarction. Thereafter, echocardiography can aid in the selection and maintenance of mechanical circulatory support and potentially facilitate the use of a percutaneous intervention.

Straightforward Design Strategy toward 3D Near-Net-Shape Stoichiometric SiC Parts.

Fused deposition modeling (FDM), traditionally reserved for thermoplastics, is modified here with a granule-based extrusion head to be extended to advanced nonoxide ceramics via a straightforward design strategy that considers the shaping opportunities and the chemical richness offered by preceramic polymers. Specifically, 3D near-net-shape stoichiometric silicon carbide (SiC) objects are designed by manipulating the key features of a commercially available polycarbosilane (fusibility, high carbon content, relatively high SiC yield). In the early stage of the process, the carbon-rich polycarbosilane is first mixed with Si and SiC fillers and then thermolyzed at 120 °C to increase polymer branching while offering tailored rheological properties during the subsequent extrusion process at 90 °C and adequate shape retention once extruded. This allows for the design of tailored and complex 3D complex polycarbosilane-based architectures with features down to 400 µm. Polymer-based parts are further converted into 3D stoichiometric SiC objects with quasi-near-net-shape-a volume shrinkage reduced to 9.1% is measured-by heat treatment at a temperature as low as 1400 °C (argon flow). Given the flexibility to tune the preceramic polymer chemical and rheological properties, a new combined design approach is leveraged to generate bespoke advanced ceramics with a high freedom in geometry complexity.

Defect engineering of 1T'MX2(M= Mo, W andX= S, Se) transition metal dichalcogenide-based electrocatalyst for alkaline hydrogen evolution reaction.

The alkaline electrolyzer (AEL) is a promising device for green hydrogen production. However, their energy conversion efficiency is currently limited by the low performance of the electrocatalysts for the hydrogen evolution reaction (HER). As such, the electrocatalyst design for the high-performance HER becomes essential for the advancement of AELs. In this work, we used both hydrogen (H) and hydroxyl (OH) adsorption Gibbs free energy changes as the descriptors to investigate the catalytic HER performance of 1T' transition metal dichalcogenides (TMDs) in an alkaline solution. Our results reveal that the pristine sulfides showed better alkaline HER performance than their selenide counterparts. However, the activities of all pristine 1T' TMDs are too low to dissociate water. To improve the performance of these materials, defect engineering techniques were used to design TMD-based electrocatalysts for effective HER activity. Our density functional theory results demonstrate that introducing single S/Se vacancy defects can improve the reactivities of TMD materials. Yet, the desorption of OH becomes the rate-determining step. Doping defective MoS2with late 3d transition metal (TM) atoms, especially Cu, Ni, and Co, can regulate the reactivity of active sites for optimal OH desorption. As a result, the TM-doped defective 1T' MoS2can significantly enhance the alkaline HER performance. These findings highlight the potential of defect engineering technologies for the design of TMD-based alkaline HER electrocatalysts.

Utility of Left and Right Ventricular Strain in Arrhythmogenic Right Ventricular Cardiomyopathy: A Prospective Multicenter Registry.

BACKGROUND: Imaging evaluation of arrhythmogenic right ventricular cardiomyopathy (ARVC) remains challenging. Myocardial strain assessment by echocardiography is an increasingly utilized technique for detecting subclinical left ventricular (LV) and right ventricular (RV) dysfunction. We aimed to evaluate the diagnostic and prognostic utility of LV and RV strain in ARVC. METHODS: Patients with suspected ARVC (n = 109) from a multicenter registry were clinically phenotyped using the 2010 ARVC Revised Task Force Criteria and underwent baseline strain echocardiography. Diagnostic performance of LV and RV strain was evaluated using the area under the receiver operating characteristic curve analysis against the 2010 ARVC Revised Task Force Criteria, and the prognostic value was assessed using the Kaplan-Meier analysis. RESULTS: Mean age was 45.3±14.7 years, and 48% of patients were female. Estimation of RV strain was feasible in 99/109 (91%), and LV strain was feasible in 85/109 (78%) patients. ARVC prevalence by 2010 ARVC Revised Task Force Criteria is 91/109 (83%) and 83/99 (84%) in those with RV strain measurements. RV global longitudinal strain and RV free wall strain had diagnostic area under the receiver operating characteristic curve of 0.76 and 0.77, respectively (both P<0.001; difference NS). Abnormal RV global longitudinal strain phenotype (RV global longitudinal strain > -17.9%) and RV free wall strain phenotype (RV free wall strain > -21.2%) were identified in 41/69 (59%) and 56/69 (81%) of subjects, respectively, who were not identified by conventional echocardiographic criteria but still met the overall 2010 ARVC Revised Task Force Criteria for ARVC. LV global longitudinal strain did not add diagnostic value but was prognostic for composite end points of death, heart transplantation, or ventricular arrhythmia (log-rank P=0.04). CONCLUSIONS: In a prospective, multicenter registry of ARVC, RV strain assessment added diagnostic value to current echocardiographic criteria by identifying patients who are missed by current echocardiographic criteria yet still fulfill the diagnosis of ARVC. LV strain, by contrast, did not add incremental diagnostic value but was prognostic for identification of high-risk patients.

A new 30-norfriedelane triterpnoid from Caloncoba lophocarpa (Oliv.) Gilg. (Achariaceae).

The chemical investigation of the methanol extract of the roots of Caloncoba lophocarpa (Oliv.) Gilg. exhibited a new 30-norfriedelane triterpenoid, laphocarpanol (1), together with seven known compounds, caloncobalactone (2), friedelin (3), friedelanol (4), asperphernamate (5), stigmasterol (6), sitosterol (7) and sitosterol-3-O-ß-D-glucopyranoside (8). The structures of the compounds were elucidated by extensive spectroscopic and spectrometric analyses (1D and 2D NMR, ESI-MS) and by comparison with previously reported data. All the compounds were tested for their antifungal and antibacterial activities. Compound 1 displayed weak antibacterial effect with MIC value of 62.5 µg/mL against Shigella flexineri. All the isolates were found to be inactive against the tested fungal strains.

Two new 30-norfriedelane triterpenes from Caloncoba glauca (P. Beauv.) Gilg (Achariaceae).

The chemical investigation of the methanolic root extract of Caloncoba glauca (P. Beauv.) Gilg exhibited two new 30-norfriedelane triterpenes, glaucalactones A and B (1-2), together with eight known compounds, caloncobalactone (3), friedelin (4), friedelanol (5), 3-oxo-friedelan-28-oic acid (6), stigmasterol (7), ß-sitosterol (8), ß-sitosterol-3-O-ß-D-glucopyranoside (9) and pentacosanoic acid (10). The structures of the isolates were elucidated by extensive spectroscopic and spectrometric analyses (1D and 2D NMR, ESI-MS) and by comparison with previously reported data. All the compounds were tested for their antioxidant, antifungal and antibacterial activities. Compound 1 displayed weak antibacterial effect with MIC value of 125 µg/mL against Staphylococcus aureus and Escherishia coli. Compound 6 exhibited moderated antifungal activity against Candida krusei with MIC value of 62.5 µg/mL. All the isolates were found to be inactive as antioxidants in the DPPH, ABTS and FRAP assays.

Sex Differences in Extensive Mitral Annular Calcification With Associated Mitral Valve Dysfunction.

Mitral annular calcification (MAC)-related mitral valve (MV) dysfunction is an increasingly recognized entity, which confers a high burden of morbidity and mortality. Although more common among women, there is a paucity of data regarding how the phenotype of MAC and the associated adverse clinical implications may differ between women and men. A total of 3,524 patients with extensive MAC and significant MAC-related MV dysfunction (i.e., transmitral gradient ≥3 mm Hg) were retrospectively analyzed from a large institutional database, with the goal of defining gender differences in clinical and echocardiographic characteristics and the prognostic importance of MAC-related MV dysfunction. We stratified patients into low- (3 to 5 mm Hg), moderate- (5 to 10 mm Hg), and high- (≥10 mm Hg) gradient groups and analyzed the gender differences in phenotype and outcome. The primary outcome was all-cause mortality, assessed using adjusted Cox regression models. Women represented the majority (67%) of subjects, were older (79.3 ± 10.4 vs 75.5 ± 10.9 years, p <0.001) and had a lower burden of cardiovascular co-morbidities than men. Women had higher transmitral gradients (5.7 ± 2.7 vs 5.3 ± 2.6 mm Hg, p <0.001), more concentric hypertrophy (49% vs 33%), and more mitral regurgitation. The median survival was 3.4 years (95% confidence interval 3.0 to 3.6) among women and 3.0 years (95% confidence interval 2.6 to 4.5) among men. The adjusted survival was worse among men, and the prognostic impact of the transmitral gradient did not differ overall by gender. In conclusion, we describe important gender differences among patients with MAC-related MV dysfunction and show worse adjusted survival among men; although, the adverse prognostic impact of the transmitral gradient was similar between men and women.

Low temperature in situ immobilization of nanoscale fcc and hcp polymorphic nickel particles in polymer-derived Si-C-O-N(H) to promote electrocatalytic water oxidation in alkaline media.

We synthesized nickel (Ni) nanoparticles (NPs) in a high specific surface area (SSA) p-block element-containing inorganic compound prepared via the polymer-derived ceramics (PDC) route to dispatch the obtained nanocomposite towards oxygen evolution reaction (OER). The in situ formation of Ni NPs in an amorphous silicon carboxynitride (Si-C-O-N(H)) matrix is allowed by the reactive blending of a polysilazane, NiCl2 and DMF followed by the subsequent thermolysis of the Ni : organosilicon polymer coordination complex at a temperature as low as 500 °C in flowing argon. The final nanocomposite displays a BET SSA as high as 311 m2 g-1 while the structure of the NPs corresponds to face-centred cubic (fcc) Ni along with interstitial-atom free (IAF) hexagonal close-packed (hcp) Ni as revealed by XRD. A closer look into the compound through FEG-SEM microscopy confirms the formation of pure metallic Ni, while HR-TEM imaging reveals the occurrence of Ni particles featuring a fcc phase and surrounded by carbon layers; thus, forming core-shell structures, along with Ni NPs in an IAF hcp phase. By considering that this newly synthesized material contains only Ni without doping (e.g., Fe) with a low mass loading (0.15 mg cm-2), it shows promising OER performances with an overpotential as low as 360 mV at 10 mA cm-2 according to the high SSA matrix, the presence of the IAF hcp Ni NPs and the development of core-shell structures. Given the simplicity, the flexibility, and the low cost of the proposed synthesis approach, this work opens the doors towards a new family of very active and stable high SSA nanocomposites made by the PDC route containing well dispersed and accessible non-noble transition metals for electrocatalysis applications.

Transesophageal Echocardiographic Screening for Structural Heart Interventions.

PURPOSE OF REVIEW: Percutaneous structural interventions have provided patients with an effective therapeutic option, and its growth has been aided by echocardiography. We describe the vital role that transesophageal echocardiography (TEE) plays in screening patients prior to their procedure. RECENT FINDINGS: A multimodality imaging approach is employed by the valve team, but TEE plays a unique role in diagnosis and planning. Utilization of all TEE views and features such as biplane, 3D imaging, and multiplanar reconstruction ensures accurate assessment of the structural lesion of interest. The role of TEE remains essential in the planning of structural interventions, and these studies should be performed in a systematic and comprehensive manner.

Apical Aneurysms and Mid-Left Ventricular Obstruction in Hypertrophic Cardiomyopathy.

BACKGROUND: Apical left ventricular (LV) aneurysms in hypertrophic cardiomyopathy (HCM) are associated with adverse outcomes. The reported frequency of mid-LV obstruction has varied from 36% to 90%. OBJECTIVES: The authors sought to ascertain the frequency of mid-LV obstruction in HCM apical aneurysms. METHODS: The authors analyzed echocardiographic and cardiac magnetic resonance examinations of patients with aneurysms from 3 dedicated programs and compared them with 63 normal controls and 47 controls with apical-mid HCM who did not have aneurysms (22 with increased LV systolic velocities). RESULTS: There were 108 patients with a mean age of 57.4 ± 13.5 years; 40 (37%) were women. A total of 103 aneurysm patients (95%) had mid-LV obstruction with mid-LV complete systolic emptying. Of the patients with obstruction, 84% had a midsystolic Doppler signal void, a marker of complete flow cessation, but only 19% had Doppler systolic gradients ≥30 mm Hg. Five patients (5%) had relative hypokinesia in mid-LV without obstruction. Aneurysm size is not bimodal but appears distributed by power law, with large aneurysms decidedly less common. Comparing mid-LV obstruction aneurysm patients with all control groups, the short-axis (SAX) systolic areas were smaller (P < 0.007), the percent SAX area change was greater (P < 0.005), the papillary muscle (PM) areas were larger (P < 0.003), and the diastolic PM areas/SAX diastolic areas were greater (P < 0.005). Patients with aneurysms had 22% greater SAX PM areas compared with those with elevated LV velocities but no aneurysms (median: 3.00 cm2 [IQR: 2.38-3.70 cm2] vs 2.45 [IQR: 1.81-2.95 cm2]; P = 0.004). Complete emptying occurs circumferentially around central PMs that contribute to obstruction. Late gadolinium enhancement was always brightest and the most transmural apical of, or at the level of, complete emptying. CONCLUSIONS: The great majority (95%) of patients in the continuum of apical aneurysms have associated mid-LV obstruction. Further research to investigate obstruction as a contributing cause to apical aneurysms is warranted.

Preparation of Confined One-Dimensional Boron Nitride Chains in the 1-D Pores of Siliceous Zeolites under High-Pressure, High-Temperature Conditions.

Low-dimensional boron nitride (BN) chains were prepared in the one-dimensional pores of the siliceous zeolites theta-one (TON) and Mobil-twelve (MTW) by the infiltration, followed by the dehydrocoupling and pyrolysis of ammonia borane under high-pressure, high-temperature conditions. High-pressure X-ray diffraction in a diamond anvil cell and in a large-volume device was used to follow in situ these different steps in order to determine the optimal conditions for this process. Based on these results, millimeter-sized samples of BN/TON and BN/MTW were synthesized. Characteristic B-N stretching vibrations of low-dimensional BN were observed by infrared and Raman spectroscopies. The crystal structures were determined using a combination of X-ray diffraction and density functional theory with one and two one-dimensional zig-zag (BN)x chains per pore in BN/TON and BN/MTW, respectively. These 1-D BN chains potentially have interesting photoluminescence properties in the far ultraviolet region of the electromagnetic spectrum.