Managing Recurrent Carbon Dioxide Embolism During Laparoscopic Hepatectomy With Transesophageal Echocardiography Guidance: A Case Report.

Carbon dioxide gas emboli is a potentially fatal complication that occurs more frequently during laparoscopic hepatectomy compared to other laparoscopic surgeries. The patient featured in this report had massive gas embolism confirmed by intraoperative transesophageal echocardiography (TEE) that were associated with episodes of severe hypoxemia, hemodynamic instability, and right ventricular failure requiring conversion to open hepatectomy. Abrupt abdominal decompression resulted in massive hemorrhage from a previously undetected defect in the middle hepatic vein.

Similar structure but different thermodynamic, dielectric, and frictional properties of confined water in twisted 2D materials: MoS graphene.

Water-based nanofluidic devices, where water is confined in Angstrom scale nanochannels, are widely encountered in nanotechnology. Although it is known that the material of confinement has a significant influence on the properties of confined water, much less is known of the relationship between the structure of nanoconfined water and its properties, impacting the design of nanofluidic devices. We explore the behavior of a confined water monolayer within a bilayer molybdenum disulfide (MoS) structure, comparing its behavior with that within bilayer graphene.

Understanding the Effects of Surface and Edge Functionalization on the Mechanical Properties of Graphene and Graphene Oxide.

Graphene oxide (GO) is a widely used 2D material employed in various applications due to its tunable properties. Understanding its mechanical properties is crucial to develop polymeric nanocomposites. We employ reactive molecular dynamics simulations to understand the effects of surface and edge functionalization of carbon atoms on the mechanical strength and fracture morphology of graphene and GO.

Machine Learnable Language for the Chemical Space of Nanopores Enables Structure-Property Relationships in Nanoporous 2D Materials.

The synthesis of nanoporous two-dimensional (2D) materials has revolutionized fields such as membrane separations, DNA sequencing, and osmotic power harvesting. Nanopores in 2D materials significantly modulate their optoelectronic, magnetic, and barrier properties. However, the large number of possible nanopore isomers makes their study onerous, while the lack of machine-learnable representations stymies progress toward structure-property relationships.

Resolving the Debate between Boltzmann and Gibbs Entropy: Relative Energy Window Eliminates Thermodynamic Inconsistencies and Allows Negative Absolute Temperatures.

Small systems consisting of a few particles are increasingly technologically relevant. In such systems, an intense debate in microcanonical statistical mechanics has been about the correctness of Boltzmann's surface entropy versus Gibbs' volume entropy. Both entropies have shortcomings─while Boltzmann entropy predicts unphysical negative/infinite absolute temperatures for small systems with an unbounded energy spectrum, Gibbs entropy entirely disallows negative absolute temperatures, in disagreement with experiments.

Generalized Model for Inhibitor-Modulated 2D Polymer Growth to Understand the Controlled Synthesis of Covalent Organic Frameworks.

Two-dimensional (2D) polymers, also known as 2D covalent organic frameworks (COFs), are increasingly finding use in applications such as membrane separations, catalysis, and energy conversion. Current research is focused on the development of new synthesis routes for COFs and obtaining a mechanistic understanding of the growth process to control it in a better manner. In this regard, synthesis methods such as reversible polycondensation termination use monofunctional inhibitor species to achieve a controlled growth rate for COFs.

Strongly facet-dependent activity of iron-doped β-nickel oxyhydroxide for the oxygen evolution reaction.

Iron (Fe)-doped β-nickel oxyhydroxide (β-NiOOH) is a highly active, noble-metal-free electrocatalyst for the oxygen evolution reaction (OER), with the latter being the bottleneck in electrochemical water splitting for sustainable hydrogen production. The mechanisms underlying how the Fe dopant modulates this host material's water electro-oxidation activity are still not entirely clear. Here, we combine hybrid density functional theory (DFT) and Hubbard-corrected DFT to investigate the OER activity of the most thermodynamically favorable (and therefore, expected to be the majority) crystallographic facets of β-NiOOH, namely (0001) and (101̄0).

Predicting Quantum-Mechanical Partial Charges in Arbitrarily Long Boron Nitride Nanotubes to Accurately Simulate Nanoscale Water Transport.

Single-walled boron nitride nanotubes (BNNTs) have been explored for various applications, ranging from water desalination to osmotic power harvesting. However, no simulation work so far has modeled the changes in the partial charge distribution when a flat sheet is rolled into a tube, hindering the ability to perform accurate molecular dynamics (MD) simulations of water flow through BNNTs. To address this knowledge gap, we employ electronic density functional theory (DFT) calculations to precisely estimate quantum-mechanically derived partial charges on boron (B) and nitrogen (N) atoms in BNNTs of varying lengths and diameters.

Incorporating ion-specific van der Waals and soft repulsive interactions in the Poisson-Boltzmann theory of electrical double layers.

Electrical double layers (EDLs) arise when an electrolyte is in contact with a charged surface, and are encountered in several application areas including batteries, supercapacitors, electrocatalytic reactors, and colloids. Over the last century, the development of Poisson-Boltzmann (PB) models and their modified versions have provided significant physical insight into the structure and dynamics of the EDL. Incorporation of physics such as finite-ion-size effects, dielectric decrement, and ion-ion correlations has made such models increasingly accurate when compared to more computationally expensive approaches such as molecular simulations and classical density functional theory.

Acute airway obstruction requiring nasotracheal intubation following hypoglossal neuromonitoring: a case report.

Background: Intraoperative neurophysiological monitoring (IONM) is utilized for both the localization of critical structures and for real time detection and prevention of intraoperative neurological injury. Use of IONM to monitor the hypoglossal nerve is performed during neurosurgical, otolaryngological, and vascular procedures to improve surgical outcomes. There is a paucity of literature describing potential complications of IONM of the hypoglossal nerve, especially with respect to airway compromise.

Incision Precision of a Novel Wire-Guided Scalpel During Central Venous Catheter Placement: A Randomized Observational Trial.

Objective: To determine whether the wire-guided scalpel (GuideBlade) improves incision precision, reduces the need to revise dermatotomy incision, improves the first-time success rate of a central venous catheter (CVC) placement, and decreases CVC-related complications.

Design: A randomized 2-arm observational trial.

Setting: At University of California Irvine Medical Center.

Enumerating Stable Nanopores in Graphene and Their Geometrical Properties Using the Combinatorics of Hexagonal Lattices.

Nanopores in two-dimensional (2D) materials, including graphene, can be used for a variety of applications, such as gas separations, water desalination, and DNA sequencing. So far, however, all plausible isomeric shapes of graphene nanopores have not been enumerated. Instead, a probabilistic approach has been followed to predict nanopore shapes in 2D materials, due to the exponential increase in the number of nanopores as the size of the vacancy increases.

Outcomes of perioperative vasopressor use for hemodynamic management of patients undergoing free flap surgery: A systematic review and meta-analysis.

This systematic review and meta-analysis investigates the objective evidence regarding outcomes in head and neck free flap surgeries using vasoactive agents in the perioperative period. A search was performed in PubMed, Cochrane, Web of Science, and Scopus databases. Inclusion criteria were clinical studies in which vasopressors were used in head and neck free flap surgery during the intraoperative and perioperative period.

Surface Roughness Explains the Observed Water Contact Angle and Slip Length on 2D Hexagonal Boron Nitride.

Hexagonal boron nitride (hBN) is a two-dimensional (2D) material that is currently being explored in a number of applications, such as atomically thin coatings, water desalination, and biological sensors. In many of these applications, the hBN surface comes into intimate contact with water. In this work, we investigate the wetting and frictional behavior of realistic 2D hBN surfaces with atomic-scale defects and roughness.

Tailoring nanoporous graphene via machine learning: Predicting probabilities and formation times of arbitrary nanopore shapes.

Nanopores in graphene, a 2D material, are currently being explored for various applications, such as gas separation, water desalination, and DNA sequencing. The shapes and sizes of nanopores play a major role in determining the performance of devices made out of graphene. However, given an arbitrary nanopore shape, anticipating its creation probability and formation time is a challenging inverse problem, solving which could help develop theoretical models for nanoporous graphene and guide experiments in tailoring pore sizes/shapes.

Chemical vapor deposition of 2D materials: A review of modeling, simulation, and machine learning studies.

Chemical vapor deposition (CVD) is extensively used to produce large-area two-dimensional (2D) materials. Current research is aimed at understanding mechanisms underlying the nucleation and growth of various 2D materials, such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (e.g.

How Grain Boundaries and Interfacial Electrostatic Interactions Modulate Water Desalination via Nanoporous Hexagonal Boron Nitride.

To fulfill the increasing demand for drinking water, researchers are currently exploring nanoporous two-dimensional materials, such as hexagonal boron nitride (hBN), as potential desalination membranes. A prominent, yet unsolved challenge is to understand how such membranes will perform in the presence of defects or surface charge in the membrane material. In this work, we study the effect of grain boundaries (GBs) and interfacial electrostatic interactions on the desalination performance of bicrystalline nanoporous hBN using classical molecular dynamics simulations supported by quantum-mechanical density functional theory (DFT) calculations.

Modulating Water Slip Using Atomic-Scale Defects: Friction on Realistic Hexagonal Boron Nitride Surfaces.

Atomic-scale defects are ubiquitous in nanomaterials, yet their role in modulating fluid flow is inadequately understood. Hexagonal boron nitride (hBN) is an important two-dimensional material with applications in desalination and osmotic power. Although pristine hBN offers higher friction to the flow of water than graphene, we show here that certain defects can enhance water slippage on hBN.

Predicting Gas Separation through Graphene Nanopore Ensembles with Realistic Pore Size Distributions.

The development of nanoporous single-layer graphene membranes for gas separation has prompted increasing theoretical investigations of gas transport through graphene nanopores. However, computer simulations and theories that predict gas permeances through individual graphene nanopores are not suitable to describe experimental results, because a realistic graphene membrane contains a large number of nanopores of diverse sizes and shapes. With this need in mind, here, we generate nanopore ensembles by etching carbon atoms away from pristine graphene with different etching times, using a kinetic Monte Carlo algorithm developed by our group for the isomer cataloging problem of graphene nanopores.

Ionic Layering and Overcharging in Electrical Double Layers in a Poisson-Boltzmann Model.

Electrical double layers (EDLs) play a significant role in a broad range of physical phenomena related to colloidal stability, diffuse-charge dynamics, electrokinetics, and energy storage applications. Recently, it has been suggested that for large ion sizes or multivalent electrolytes, ions can arrange in a layered structure inside the EDLs. However, the widely used Poisson-Boltzmann models for EDLs are unable to capture the details of ion concentration oscillations and the effect of electrolyte valence on such oscillations.

Facet-Independent Oxygen Evolution Activity of Pure β-NiOOH: Different Chemistries Leading to Similar Overpotentials.

β-Nickel oxyhydroxide (β-NiOOH) is a promising electrocatalyst for the oxygen evolution reaction (OER), which is the more difficult half-reaction involved in water splitting. In this study, we revisit the OER activities of the two most abundant crystallographic facets of pristine β-NiOOH, the (0001) and (1010) facets, which expose 6-fold-lattice-oxygen-coordinated and 5-fold-lattice-oxygen-coordinated Ni sites, respectively. To this end, we model various active sites on these two facets using hybrid density functional theory, which includes a fraction of the exact nonlocal Fock exchange in the electronic description of the system.

A Prospective Observational Cohort Study of Calls for Help in a Tertiary Care Academic Operating Room Suite.

While significant literature exists on hospital-based "code calls," there is a lack of research on calls for help in the operating room (OR). The purpose of this study was to quantify the rate and nature of calls for help in the OR of a tertiary care hospital. For a 1-year period, all calls were recorded in the main OR at The University of California, Irvine Medical Center.

Ventricular Fibrillation Refractory to Cutaneous Electrical Defibrillation in a Morbidly Obese Pediatric Patient With Hypertrophic Cardiomyopathy: A Case Report.

We report a case of subcutaneous implantable cardioverter-defibrillator implantation in a morbidly obese pediatric patient with hypertrophic cardiomyopathy for the primary prevention of sudden cardiac death. During routine defibrillator threshold testing of the newly placed subcutaneous implantable cardioverter defibrillator, normal sinus rhythm could not be restored despite repeated attempts at defibrillation using the subcutaneous implantable cardioverter defibrillator and transcutaneous pads. Here, we describe the successful intraoperative resuscitation and management after failure to restore normal sinus rhythm using the newly placed subcutaneous implantable cardioverter defibrillator and repeated transcutaneous defibrillation attempts.

Repeat Subdural Hematoma After Uncomplicated Lumbar Drain Discontinuation: A Case Report.

Lumbar drains are commonly placed to monitor spinal cerebrospinal fluid (CSF) pressures and drain CSF to augment spinal cord perfusion. Excessive CSF drainage or persistent leakage through the dural puncture site can lead to cerebral hypotension and creation of an intracranial subdural hematoma. Anesthesia providers need to be aware of the risk of subdural hematoma development after major thoracoabdominal surgery where placement and subsequent removal of a lumbar drain have occurred.