Cellular Pre-Adaptation to the High O2 Concentration Used in Standard Cell Culture Confers Resistance to Subsequent H2O2-Induced Cell Death.

The addition of hydrogen peroxide (H2O2) to cultured cells is widely used as a method to modulate redox-regulated cellular pathways, including the induction of programmed cell death in cell culture experiments and the testing of pro- and antioxidant compounds. Here, we assessed the effect on the cellular response to H2O2 of pre-adapting squamous cell carcinoma cells (A431) to the standard cell culture oxygenation of 18.6% O2, compared to cells pre-adapted to a physiological skin O2 concentration (3.0% O2). We showed that cells pre-adapted to 18.6% O2 resisted H2O2-induced cell death compared to cells pre-adapted to 3.0% O2 for 96 h prior to treatment with H2O2. Moreover, the enzymatic activities of catalase and glutathione reductase, as well as the protein expression levels of catalase, were higher in cells pre-adapted to 18.6% O2 compared to cells pre-adapted to 3.0% O2. H2O2-resistant cells, pre-adapted to 18.6% O2, exhibited increased nuclear Nrf-2 levels. It is concluded that A431 cells pre-adapted to standard cell culture oxygenation conditions resist H2O2-induced cell death. This effect may be related to their heightened activation of Nrf-2.

A lithium-air battery and gas handling system demonstrator.

The lithium-air (Li-air) battery offers one of the highest practical specific energy densities of any battery system at >400 W h kgsystem-1. The practical cell is expected to operate in air, which is flowed into the positive porous electrode where it forms Li2O2 on discharge and is released as O2 on charge. The presence of CO2 and H2O in the gas stream leads to the formation of oxidatively robust side products, Li2CO3 and LiOH, respectively. Thus, a gas handling system is needed to control the flow and remove CO2 and H2O from the gas supply. Here we present the first example of an integrated Li-air battery with in-line gas handling, that allows control over the flow and composition of the gas supplied to a Li-air cell and simultaneous evaluation of the cell and scrubber performance. Our findings reveal that O2 flow can drastically impact the capacity of cells and confirm the need for redox mediators. However, we show that current air-electrode designs translated from fuel cell technology are not suitable for Li-air cells as they result in the need for higher gas flow rates than required theoretically. This puts the scrubber under a high load and increases the requirements for solvent saturation and recapture. Our results clarify the challenges that must be addressed to realise a practical Li-air system and will provide vital insight for future modelling and cell development.

Voltammetric Evidence of Proton Transport through the Sidewalls of Single-Walled Carbon Nanotubes.

Understanding ion transport in solid materials is crucial in the design of electrochemical devices. Of particular interest in recent years is the study of ion transport across 2-dimensional, atomically thin crystals. In this contribution, we describe the use of a host-guest hybrid redox material based on polyoxometalates (POMs) encapsulated within the internal cavities of single-walled carbon nanotubes (SWNTs) as a model system for exploring ion transport across atomically thin structures. The nanotube sidewall creates a barrier between the redox-active molecules and bulk electrolytes, which can be probed by addressing the redox states of the POMs electrochemically. The electrochemical properties of the {POM}@SWNT system are strongly linked to the nature of the cation in the supporting electrolyte. While acidic electrolytes facilitate rapid, exhaustive, reversible electron transfer and stability during redox cycling, alkaline-salt electrolytes significantly limit redox switching of the encapsulated species. By "plugging" the {POM}@SWNT material with C60-fullerenes, we demonstrate that the primary mode of charge balancing is proton transport through the graphenic lattice of the SWNT sidewalls. Kinetic analysis reveals little kinetic isotope effect on the standard heterogeneous electron transfer rate constant, suggesting that ion transport through the sidewalls is not rate-limiting in our system. The unique capacity of protons and deuterons to travel through graphenic layers unlocks the redox chemistry of nanoconfined redox materials, with significant implications for the use of carbon-coated materials in applications ranging from electrocatalysis to energy storage and beyond.

Host-Guest Chemistry in Boron Nitride Nanotubes: Interactions with Polyoxometalates and Mechanism of Encapsulation.

Boron nitride nanotubes (BNNTs) are an emerging class of molecular container offering new functionalities and possibilities for studying molecules at the nanoscale. Herein, BNNTs are demonstrated as highly effective nanocontainers for polyoxometalate (POM) molecules. The encapsulation of POMs within BNNTs occurs spontaneously at room temperature from an aqueous solution, leading to the self-assembly of a POM@BNNT host-guest system. Analysis of the interactions between the host-nanotube and guest-molecule indicate that Lewis acid-base interactions between W═O groups of the POM (base) and B-atoms of the BNNT lattice (acid) likely play a major role in driving POM encapsulation, with photoactivated electron transfer from BNNTs to POMs in solution also contributing to the process. The transparent nature of the BNNT nanocontainer allows extensive investigation of the guest-molecules by photoluminescence, Raman, UV-vis absorption, and EPR spectroscopies. These studies revealed considerable energy and electron transfer processes between BNNTs and POMs, likely mediated via defect energy states of the BNNTs and resulting in the quenching of BNNT photoluminescence at room temperature, the emergence of new photoluminescence emissions at cryogenic temperatures (<100 K), a photochromic response, and paramagnetic signals from guest-POMs. These phenomena offer a fresh perspective on host-guest interactions at the nanoscale and open pathways for harvesting the functional properties of these hybrid systems.

Stabilization of Polyoxometalate Charge Carriers via Redox-Driven Nanoconfinement in Single-Walled Carbon Nanotubes.

We describe the preparation of hybrid redox materials based on polyoxomolybdates encapsulated within single-walled carbon nanotubes (SWNTs). Polyoxomolybdates readily oxidize SWNTs under ambient conditions in solution, and here we study their charge-transfer interactions with SWNTs to provide detailed mechanistic insights into the redox-driven encapsulation of these and similar nanoclusters. We are able to correlate the relative redox potentials of the encapsulated clusters with the level of SWNT oxidation in the resultant hybrid materials and use this to show that precise redox tuning is a necessary requirement for successful encapsulation. The host-guest redox materials described here exhibit exceptional electrochemical stability, retaining up to 86 % of their charge capacity over 1000 oxidation/reduction cycles, despite the typical lability and solution-phase electrochemical instability of the polyoxomolybdates we have explored. Our findings illustrate the broad applicability of the redox-driven encapsulation approach to the design and fabrication of tunable, highly conductive, ultra-stable nanoconfined energy materials.

Electrochemistry of redox-active molecules confined within narrow carbon nanotubes.

Confinement of molecules within nanocontainers can be a powerful tool for controlling the states of guest-molecules, tuning properties of host-nanocontainers and triggering the emergence of synergistic properties within the host-guest systems. Among nanocontainers, single-walled carbon nanotubes - atomically thin cylinders of carbon, with typical diameters below 2 nm and lengths reaching macroscopic dimensions - are ideal hosts for a variety of materials, including inorganic crystals, and organic, inorganic and organometallic molecules. The extremely high aspect ratio of carbon nanotubes is complemented by their functional properties, such as exceptionally high electrical conductivity and thermal, chemical and electrochemical stability, making carbon nanotubes ideal connectors between guest-molecules and macroscopic electrodes. The idea of harnessing nanotubes both as nanocontainers and nanoelectrodes has led to the incorporation of redox-active species entrapped within nanotube cavities where the host-nanotubes may serve as conduits of electrons to/from the guest-molecules, whilst restricting the molecular positions, orientations, and local environment around the redox centres. This review gives a contemporary overview of the status of molecular redox chemistry within ultra-narrow carbon nanotubes (nanotubes with diameters approaching molecular dimensions) highlighting the opportunities, pitfalls, and gaps in understanding of electrochemistry in confinement, including the role of nanotube diameter, size and shape of guest-molecules, type of electrolyte, solvent and other experimental conditions.

Single-molecule imaging and kinetic analysis of intermolecular polyoxometalate reactions.

We induce and study reactions of polyoxometalate (POM) molecules, [PW12O40]3- (Keggin) and [P2W18O62]6- (Wells-Dawson), at the single-molecule level. Several identical carbon nanotubes aligned side by side within a bundle provided a platform for spatiotemporally resolved imaging of ca. 100 molecules encapsulated within the nanotubes by transmission electron microscopy (TEM). Due to the entrapment of POM molecules their proximity to one another is effectively controlled, limiting molecular motion in two dimensions but leaving the third dimension available for intermolecular reactions between pairs of neighbouring molecules. By coupling the information gained from high resolution structural and kinetics experiments via the variation of key imaging parameters in the TEM, we shed light on the reaction mechanism. The dissociation of W-O bonds, a key initial step of POM reactions, is revealed to be reversible by the kinetic analysis, followed by an irreversible bonding of POM molecules to their nearest neighbours, leading to a continuous tungsten oxide nanowire, which subsequently transforms into amorphous tungsten-rich clusters due to progressive loss of oxygen atoms. The overall intermolecular reaction can therefore be described as a step-wise reductive polycondensation of POM molecules, via an intermediate state of an oxide nanowire. Kinetic analysis enabled by controlled variation of the electron flux in TEM revealed the reaction to be highly flux-dependent, which leads to reaction rates too fast to follow under the standard TEM imaging conditions. Although this presents a challenge for traditional structural characterisation of POM molecules, we harness this effect by controlling the conditions around the molecules and tuning the imaging parameters in TEM, which combined with theoretical modelling and image simulation, can shed light on the atomistic mechanisms of the reactions of POMs. This approach, based on the direct space and real time chemical reaction analysis by TEM, adds a new method to the arsenal of single-molecule kinetics techniques.

The Effects of Harm Events on 30-Day Readmission in Surgical Patients.

ABSTRACT: Readmission is an increasingly important focus for improvement regarding quality, value, and patient burden in our surgical patient population. We hypothesized that inpatient harm events increase the likelihood of readmission in surgical patients. We created a system-wide inpatient registry with 30-day readmission. A surgical subset was created, and harm events were tracked through the electronic health record system. Between 2015 and 2017, 37,048 surgical patient encounters met inclusion criterion. A total of 2,887 patients (7.69%) were readmitted. After multiple logistic regression of the highly significant harm measures, seven harm measures remained statistically significant (p < .05). Those with the three highest odds ratios were mucosal pressure ulcer, Clostridium difficile, and glucose <40. Incorporating harm measures to the traditional risk, predictive model for 30-day readmission improved our model performance (area under the ROC curve from 0.68 to 0.71). This study demonstrated that inpatient hospital-based harm events can be electronically monitored and used to predict 30-day readmission.

Weighting of Measures in the Safety of Care Group of the Overall Hospital Quality Star Rating Program: An Alternative Approach.

The Centers for Medicare & Medicaid Services' Overall Hospital Quality Star Rating program has raised concerns since its introduction in 2016. Using both national data and data from a large urban teaching hospital, the authors examined a few methodological issues of one heavily weighted measure group, the Safety of Care group. The authors investigated the validity of the assumption that a single underlying quality trait exists among the 8 Safety measures, and the sensitivity of the Safety group score in response to a range of measure improvement scenarios. Also explored were the effects of an alternative weighting method and an alternative measure score calculation method on the results of a single hospital's Safety group score. Evidence was found for 4 (rather than 1) underlying quality dimensions among the 8 Safety measures, and the Safety group score calculated using the current method was notably different from that calculated using the alternative methods.

Venous Thromboembolism in Neurocritical Care Patients.

BACKGROUND: Venous thromboembolism (VTE) is a potentially life-threatening complication among critically ill patients. Neurocritical care patients are presumed to be at high risk for VTE; however, data regarding risk factors in this population are limited. We designed this study to evaluate the frequency, risk factors, and clinical impact of VTE in neurocritical care patients. METHODS: We obtained data from the electronic medical record of all adult patients admitted to neurological intensive care unit (NICU) at Henry Ford Hospital between January 2015 and March 2018. Venous thromboembolism was defined as deep vein thrombosis, pulmonary embolism, or both diagnosed by Doppler, chest computed tomography (CT) angiography or ventilation-perfusion scan >24 hours after admission. Patients with ICU length of stay <24 hours or who received therapeutic anticoagulants or were diagnosed with VTE within 24 hours of admission were excluded. RESULTS: Among 2188 consecutive NICU patients, 63 (2.9%) developed VTE. Prophylactic anticoagulant use was similar in patients with and without VTE (95% vs 92%; P = .482). Venous thromboembolism was associated with higher mortality (24% vs 13%, P = .019), and longer ICU (12 [interquartile range, IQR 5-23] vs 3 [IQR 2-8] days, P < .001) and hospital (22 [IQR 15-36] vs 8 [IQR 5-15] days, P < .001) length of stay. In a multivariable analysis, potentially modifiable predictors of VTE included central venous catheterization (odds ratio [OR] 3.01; 95% confidence interval [CI], 1.69-5.38; P < .001) and longer duration of immobilization (Braden activity score <3, OR 1.07 per day; 95% CI, 1.05-1.09; P < .001). Nonmodifiable predictors included higher International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) scores (which accounts for age >60, prior VTE, cancer and thrombophilia; OR 1.66; 95% CI, 1.40-1.97; P < .001) and body mass index (OR 1.05; 95% CI, 1.01-1.08; P = .007). CONCLUSIONS: Despite chemoprophylaxis, VTE still occurred in 2.9% of neurocritical care patients. Longer duration of immobilization and central venous catheterization are potentially modifiable risk factors for VTE in critically ill neurological patients.

Host-Guest Hybrid Redox Materials Self-Assembled from Polyoxometalates and Single-Walled Carbon Nanotubes.

The development of next-generation molecular-electronic, electrocatalytic, and energy-storage systems depends on the availability of robust materials in which molecular charge-storage sites and conductive hosts are in intimate contact. It is shown here that electron transfer from single-walled carbon nanotubes (SWNTs) to polyoxometalate (POM) clusters results in the spontaneous formation of host-guest POM@SWNT redox-active hybrid materials. The SWNTs can conduct charge to and from the encapsulated guest molecules, allowing electrical access to >90% of the encapsulated redox species. Furthermore, the SWNT hosts provide a physical barrier, protecting the POMs from chemical degradation during charging/discharging and facilitating efficient electron transfer throughout the composite, even in electrolytes that usually destroy POMs.

Different Harm and Mortality in Critically Ill Medical vs Surgical Patients: Retrospective Analysis of Variation in Adverse Events in Different Intensive Care Units.

BACKGROUND: Institutional harm reduction campaigns are essential in improving safe practice in critical care. Our institution embarked on an aggressive project to measure harm. We hypothesized that critically ill surgical patients were at increased risk of harm compared with medical intensive care patients. METHODS: Three years of administrative data for patients with at least 1 Intensive Care Unit day at an urban tertiary care center were assembled. Data were accessed from the Henry Ford Health System No Harm Campaign in Detroit, MI. Harm was defined as any unintended physical injury resulting from medical care. Patients were deemed surgical if they had at least 1 procedure in the operating room. Univariate analysis was used to compare surgical patients with nonsurgical. Logistic regression was used for risk adjustment in predicting harm and death. RESULTS: The study included 19,844 patients, of whom 7483 (37.7%) were surgical. The overall mortality was 7.8% (n = 1554). More surgical patients experienced harm than did nonsurgical patients (2923 [39.1%] vs 2798 [22.6%], odds ratio [OR] = 2.2, p < 0.001). Surgical patients were less likely to die (6.2% vs 8.8%, p < 0.001). Surgical patients were more likely to experience harm (OR = 2.1) but had lower mortalities (OR = 0.45) vs other harmed patients (OR = 3.8; all p < 0.001). CONCLUSION: Most harm in surgically critically ill patients is procedure related. Preliminary data show that harm is associated with death, yet both surgical and African American patients experience more harm with a lower mortality rate.

Associations Between Community Sociodemographics and Performance in HEDIS Quality Measures: A Study of 22 Medical Centers in a Primary Care Network.

Evaluation and payment for health plans and providers have been increasingly tied to their performance on quality metrics, which can be influenced by patient- and community-level sociodemographic factors. The aim of this study was to examine whether performance on Healthcare Effectiveness Data and Information Set (HEDIS) measures varied as a function of community sociodemographic characteristics at the primary care clinic level. Twenty-two primary care sites of a large multispecialty group practice were studied during the period of April 2013 to June 2016. Significant associations were found between sites' performance on selected HEDIS measures and their neighborhood sociodemographic characteristics. Outcome measures had stronger associations with sociodemographic factors than did process measures, with a range of significant correlation coefficients (absolute value, regardless of sign) from 0.44 to 0.72. Sociodemographic factors accounted for as much as 25% to 50% of the observed variance in measures such as HbA1c or blood pressure control.

Three-dimensionally printed polyetherketoneketone scaffolds with mesenchymal stem cells for the reconstruction of critical-sized mandibular defects.

OBJECTIVE: Additive manufacturing offers a tailored approach to tissue engineering by providing anatomically precise scaffolds onto which stem cells and growth factors can be supplied. Polyetherketoneketone (PEKK), an ideal candidate biomaterial, is limited by a poor implant-bone interface but can be functionalized with adipose-derived stem cells (ADSC) to promote integration. This in vivo study examined the interaction of a three-dimensional printed PEKK/ADSC implant within the critical-sized mandibular defect in a rabbit model. STUDY DESIGN/METHODS: Trapezoidal porous scaffolds with dimensions of 1.5 × 1.0 × 0.5 cm were printed using selective laser sintering. ADSCs were seeded on the scaffolds that were then implanted in marginal defects created in New Zealand rabbits. Rabbits were euthanized at 10- and 20-week intervals. Microcomputed tomography was used to characterize bone ingrowth and was correlated with histological analysis. Stress testing was performed on the scaffolds before and after implantation. RESULTS: All scaffolds were well integrated into adjacent bone. Bone-to-tissue volume increased from 30.34% ( ± 12.46) to 61.27% ( ± 8.24), and trabecular thickness increased from 0.178 mm ( ± 0.069) to 0.331 mm ( ± 0.0306) in the 10- and 20-week groups, respectively, compared to no bone regrowth on the control side (P < 0.05). Histology confirmed integration at the bone-implant interface. Biomechanical testing revealed a compressive resistance 15 times that of bone alone (P < 0.05) CONCLUSION: 3D-printed PEKK scaffolds combined with ADSCs present a promising solution to improve the bone-implant interface and increase the resistance to forces of mastication after mandibular reconstruction. LEVEL OF EVIDENCE: NA. Laryngoscope, 127:E392-E398, 2017.

Correlations Among Hospital Quality Measures: What "Hospital Compare" Data Tell Us.

A number of quality rating systems to rank health care providers have been developed over the years with the intention of helping consumers make informed health care purchasing decisions. Many use sets of individual quality measures to calculate a global rating. The utility of a global rating for consumer choice hinges on the relationships among included measures and the extent to which they jointly reflect an underlying dimension of quality. Publicly reported data on 4 quality domains-complication, mortality, readmission, and patient safety-from Centers for Medicare & Medicaid Services' Hospital Compare website were used to examine correlations among individual measures within each measure group (within-group correlations) and correlations between pairs of measures across different measure groups (between-group correlations). Modest within-group correlations were found in only 2 domains (mortality and readmission), and there were no meaningful between-group associations. These findings raise questions about whether consumers can reliably depend on global quality ratings to make informed decisions.

Three-Dimensional Printed Scaffolds with Multipotent Mesenchymal Stromal Cells for Rabbit Mandibular Reconstruction and Engineering.

Multipotent mesenchymal stromal cells (MSC) derived from both the bone marrow and adipose tissue possess the ability to differentiate into multiple cell lineages, regulate the immune function by secreting numerous bioactive paracrine factors, and hold great potential in cell therapy and tissue engineering. When combined with three-dimensional (3D) scaffolds, MSC can be used for bone defect reconstruction and engineering. This protocol describes the isolation of bone marrow mesenchymal stromal cells (BMMSC) and adipose-tissue derived stem cells (ADSC) from rabbits for subsequent seeding on tissue-engineered 3D-printed scaffolds and transplantation into a rabbit-model with the goal of repairing large osseous mandibular defects (one quarter of the lower jaw is removed surgically). Steps to demonstrate the three cell differentiation lineage potentials of BMMSC and ADSC into osteocytes, adipocytes, and chondrocytes are described. A modified cell seeding method using syringes on scaffold is detailed. Creating a large mandibular bone defect, the rapid prototyping method to print a customized 3D-scaffold, the scaffold implantation procedure in rabbits, and microcomputed tomography (micro-CT) analysis are also described.

Is Exposure to Suicide Beyond Kin Associated with Risk for Suicidal Behavior? A Systematic Review of the Evidence.

Suicide bereavement and postvention literature often espouses risk for subsequent suicidal behavior among those previously exposed to a suicide death. Most often risk is discussed in relation to kin; however, many more individuals are exposed to suicide, and the impact of this exposure is important to understand in relation to targeting postvention. This review examined the research literature (1990-2014) to determine the evidence base for risk among those exposed to suicide. The findings demonstrate that risk of suicidal behaviors among those exposed to the suicide is significantly higher than those unexposed. These results are discussed within the context of current research in the field of postvention, and suggestions for future research are suggested.

Improving PEEK bioactivity for craniofacial reconstruction using a 3D printed scaffold embedded with mesenchymal stem cells.

OBJECTIVE: Polyetheretherketone (PEEK) is a bioinert thermoplastic that has been investigated for its potential use in craniofacial reconstruction; however, its use in clinical practice is limited by a poor integration with adjacent bone upon implantation. To improve the bone-implant interface, two strategies have been employed: to modify its surface or to impregnate PEEK with bioactive materials. This study attempts to combine and improve upon the two approaches by modifying the internal structure into a trabecular network and to impregnate PEEK with mesenchymal stem cells. Furthermore, we compare the newly designed PEEK scaffolds' interactions with both bone-derived (BMSC) and adipose (ADSC) stem cells. DESIGN: Customized PEEK scaffolds were designed to incorporate a trabecular microstructure using a computer-aided design program and then printed via selective laser sintering (SLS), a 3D-printing process with exceptional accuracy. The scaffold structure was evaluated using microCT. Scanning electron microscopy (SEM) was used to evaluate scaffold morphology with and without mesenchymal stem cells (MSCs). Adipose and bone marrow mesenchymal cells were isolated from rats and cultured on scaffolds. Cell proliferation and differentiation were assessed using alamarBlue and alkaline phosphatase assays, respectively. Cell morphology after one week of co-culturing cells with PEEK scaffolds was evaluated using SEM. RESULTS: SLS 3D printing fabricated scaffolds with a porosity of 36.38% ± 6.66 and density of 1.309 g/cm(2). Cell morphology resembled viable fibroblasts attaching to the surface and micropores of the scaffold. PEEK scaffolds maintained the viability of both ADSCs and BMSCs; however, ADSCs demonstrated higher osteodifferentiation than BMSCs (p < 0.05). CONCLUSIONS: This study demonstrates for the first time that SLS 3D printing can be used to fabricate customized porous PEEK scaffolds that maintain the viability of adipose and bone marrow-derived MSCs and induce the osteodifferentiation of the adipose-derived MSCs. The combination of 3D printed PEEK scaffolds with MSCs could overcome some of the limitations using PEEK biopolymers for load-bearing bone regeneration in craniofacial reconstruction.