High-Tribological-Performance Polymer Nanocomposites: An Approach Based on the Superlubricity State of the Graphene Oxide Agglomerates.

Here, nanocomposites of high-molecular-weight polyethylene (HMWPE) and HMWPE-UHMWPE (80/20 wt.%) containing a low amount of multilayer graphene oxide (mGO) (≤0.1 wt.%) were produced via twin-screw extrusion to produce materials with a higher tribological performance than UHMWPE. Due to the high viscosity of both polymers, the nanocomposites presented a significant concentration of agglomerates. However, the mechanical (tensile) and tribological (volumetric loss) performances of the nanocomposites were superior to those of UHMWPE. The morphology of the nanocomposites was investigated using differential scanning calorimetry (DSC), microtomography, and transmission electron microscopy (TEM). The explanation for these results is based on the superlubricity phenomenon of mGO agglomerates. It was also shown that the well-exfoliated mGO also contained in the nanocomposite was of fundamental importance as a mechanical reinforcement for the polymer. Even with a high concentration of agglomerates, the nanocomposites displayed tribological properties superior to UHMWPE's (wear resistance up to 27% higher and friction coefficient up to 57% lower). Therefore, this manuscript brings a new exception to the rule, showing that agglomerates can act in a beneficial way to the mechanical properties of polymers, as long as the superlubricity phenomenon is present in the agglomerates contained in the polymer.

Stability Changes in Iridium Nanoclusters via Monoxide Adsorption: A DFT Study within the van der Waals Corrections.

Small iridium nanoclusters are prominent subnanometric systems for catalysis-related applications, mainly because of a large surface-to-volume ratio, noncoalescence feature, and tunable properties, which are completely influenced by the number of atoms, geometry, and molecular interaction with the chemical environment. Herein, we investigate the interaction between Irn nanoclusters (n = 2-7) and polluting molecules, CO, NO, and SO, using van der Waals D3 corrected density functional theory calculations. Starting from a representative structural set, we determine the growth pattern of the lowest energy unprotected Irn nanoclusters, which is based on open structural motifs, and from the adsorption of a XO (X = C, N, and S) molecule, the preferred high-symmetric adsorption sites were determined, dominated by the onefold top site. For protected systems, 4XO/Ir4 and 6XO/Ir6, we found a reduction in the total magnetic moment, while the equilibrium bonds of the nanoclusters expanded (contracted) due to mCO and mNO (mSO) adsorption, with exceptions for systems with large structural distortions (4SO/Ir4 and 6NO/Ir6). Meanwhile, the C-O and N-O (S-O) bond strength decreases (increases) following an increase (decrease) in the C-O and N-O (S-O) distances upon adsorption. We show, through energetic analysis, that for the different chemical environments, relative stability changes occur from the most stable unprotected nanoclusters, planar square (Ir4), and prism (Ir6) to higher energy isomers. The change in the stability order between the two competing protected systems is feasible if the balance between the interaction energy (additive term) and distortion energies (nonadditive terms) compensates for the relative total energies of the unprotected configurations. For all systems, the interaction energy is the main reason responsible for stability alterations, except for 4SO/Ir4, where the main contribution is from a small penalty due to Ir4 distortions upon adsorption, and for 4NO/Ir4, where the energetic effects from the adsorption do not overcome the difference between the binding energies of the unprotected nanoclusters. Finally, from energy decomposition and Hirshfeld charge analysis, we find a predominant covalent nature of the physical contributions in mOX···Irn interactions with a cationic core (Irn) and an anionic shell (XO coverage).

Shielding effectiveness of X-ray protective garment.

PURPOSE: Certification of the X-ray shielding garment is based on attenuation testing on flat material samples. We investigated the difference of shielding effectiveness compared to realistic use when the garment is worn on the body of a staff person. METHODS: Attenuation factors of X-ray protective aprons have been evaluated for several clinical scenarios with Monte Carlo (MC) calculations based on the ICRP female reference model and an experimental setup. The MC calculated attenuation factors refer to the effective dose E, whereas the measured attenuation factors refer to the personal dose equivalent Hp(10). The calculated/measured factors were compared to the attenuation factors of the identical materials measured under the conditions of the standard IEC 61331-1 that is currently in use for the type testing of X-ray protective aprons. RESULTS: As a result, for example, at a common tube voltage of 80 kV, the real attenuation factors of a 0.35 mm Pb apron worn by a 3-dimensional body were 38% to 76% higher than when measured under IEC conditions on flat samples. The MC-calculated organ doses show the maximum contribution to E being within the operators abdomen/pelvis region. CONCLUSIONS: With our findings, personal X-ray protective garments could be improved in effectiveness.

The Impact of Environmental Factors on the Mortality of Patients With Chronic Heart Failure.

Outcomes of acute heart failure hospitalizations are worse during the winter than the rest of the year. Seasonality data are more limited for outcomes in chronic heart failure and the effect of environmental variables is unknown. In this population-level study, we merged 20-year data for 555,324 patients with heart failure from the national Veterans Administration database with data on climate from the National Oceanic and Atmospheric Administration and air pollutants by the Environmental Protection Agency. The outcome was the all-cause mortality rate, stratified by geographical location and each month. The impact of environmental factors was assessed through Pearson's correlation and multiple regression with a family-wise α = 0.05. The monthly all-cause mortality was 13.9% higher in the winter than the summer, regardless of gender, age group, and heart failure etiology. Winter season, lower temperatures, and higher concentrations of nitrogen dioxide were associated with a higher mortality rate in multivariate analysis of the overall population. Different environmental factors were associated in regions with similar patterns of temperature and precipitation. The only environmental factor associated with the mortality rate of patients dwelling in large urban centers was the air quality index. In conclusion, the mortality in chronic heart failure exhibits a seasonal pattern, regardless of latitude or climate. In this group of patients, particularly those of male gender, a higher mortality was associated with environmental factors and incorporating these factors in treatment plans and recommendations could have a favorable cost-benefit ratio.

The Effect of Calcium Channel Blockers on Moderate or Severe Albuminuria in Diabetic, Hypertensive Patients.

OBJECTIVES: Inhibitors of the renin-angiotensin system are recommended for the management of albuminuria in patients with hypertension and diabetes mellitus, but there is little consensus about alternative therapies. Calcium channel blockers are recommended for the management of hypertension, but the data are controversial regarding their role in patients with albuminuria. This review was designed to assess the efficacy of calcium channel blockers compared with inhibitors of the renin-angiotensin system in decreasing albuminuria in diabetic, hypertensive patients with nephropathy. METHODS: We searched MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov for records that compared calcium channel blockers to inhibitors of the renin-angiotensin system and reported pre- and postintervention albuminuria measurements. Two reviewers independently screened abstracts for randomized, controlled trials in adults. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to select 29 trials from 855 records. We synthesized the data through a random-effects model. RESULTS: We analyzed data from 2113 trial participants with hypertension and diabetes mellitus who had the equivalent of ≥30 mg/day of urinary albumin excretion. Inhibitors of the renin-angiotensin system were more effective than calcium channel blockers in decreasing albuminuria (standardized difference in means -0.442; confidence interval, -0.660 to -0.225; P < .001). This finding was independent of the blood pressure response to treatment. There was no difference between the 2 drug classes regarding markers of renal function. CONCLUSIONS: Inhibitors of the renin-angiotensin system are superior to calcium channel blockers for the reduction of albuminuria in nephropathy due to hypertension and diabetes mellitus. The net clinical benefit, however, is small.

TERTIARY X-RADIATION-A PROBLEM FOR STAFF PROTECTION?

The influence of tertiary x-radiation on the radiological staff is widely unknown. Tertiary radiation is caused as the scattered radiation of the patient impacts the walls, floor, ceiling and surrounding air. The question that arises is does tertiary x-radiation provide a relevant contribution to the staff doses. The impact of tertiary radiation was investigated by means of measurements of the personal dose equivalent Hp(10) on an anthropomorphic Alderson Rando male phantom and also on operators/assistants staying in clinical practice. Further, the protective effect of lead foils, especially under tertiary radiation was also investigated. Correlations could be derived for clinical angiographic/interventional procedures between dose area products (DAPs) and dose length products (DLPs) vs. dorsal doses of staff persons. Generally, the staff doses that are a result of tertiary radiation depend on the x-ray energy and range from 0.15 to 0.55% of the scattered radiation impact caused by irradiation of the patient. Hence, a back panel with 0.125-mm lead equivalent is sufficient to protect the staff from tertiary radiation created within the room environment.

Prognostic Utility of Troponin I and N Terminal-ProBNP among Patients with Heart Failure due to Non-Ischemic Cardiomyopathy and Important Correlations.

BACKGROUND: Heart Failure (HF) is accompanied by a high cost of care and gloomy prognosis despite recent advances in its management. Therefore, efforts to minimize HF rehospitalizations is a major focus of several studies. METHODS: We conducted a retrospective cohort study of 140 patients 18 years and above who had baseline clinical parameters, echocardiography, NT-ProBNP, troponin I and other laboratory parameters following a 3-year electronic medical record review. Patients with coronary artery disease, preserved ejection fraction, pulmonary embolism, cancer, and end-stage renal disease were excluded. RESULTS: Of the 140 patients admitted with HF with reduced Ejection Fraction (HFrEF) secondary to non-ischemic cardiomyopathy, 15 were re-hospitalized within 30 days of discharge while 42 were rehospitalized within 6 months after discharge for decompensated HF. Receiver operating characteristic (ROC) cutoff points were obtained for NT-ProBNP at 5178 pg/ml and serum troponin I at 0.045 ng/ml. After Cox regression analysis, patients with HFrEF who had higher hemoglobin levels had reduced odds of re-hospitalization (p = 0.007) within 30 days after discharge. NT-ProBNP and troponin I were independent predictors of re-hospitalization at 6 months after discharge (p = 0.047 and p = 0.02), respectively, after Cox regression analysis. CONCLUSION: Troponin I and NT-ProBNP at admission are the best predictors of re-hospitalization 6 months after discharge among patients with HFrEF. Hemoglobin is the only predictor of 30 -day rehospitalization among HFrEF patients in this study. High-risk patients may require aggressive therapy to improve outcomes.

The Effect of Vegan Diets on Blood Pressure in Adults: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Vegan diets are increasing in popularity and have beneficial effects on glycemia and blood lipids, but the evidence is inconclusive regarding their effect on blood pressure. The purpose of this study was to review the effect of vegan diets on blood pressure in adults. METHODS: We searched MEDLINE, EMBASE, CENTRAL, and ClinicalTrials.gov for records that compared a vegan diet with any less restrictive diet and reported pre- and postintervention systolic and diastolic blood pressures. Two reviewers independently screened abstracts for randomized, controlled clinical trials in individuals ≥18 years of age and older. We used the PRISMA guidelines to select 11 clinical trials from 1673 records. Data synthesis was performed through a random-effects model. RESULTS: The pooled data included 983 participants. Compared with less restrictive diets, a vegan diet did not result in a significant change in systolic (-1.33 mm Hg; 95% confidence interval [CI], -3.50-0.84; P = .230) or diastolic (-1.21 mm Hg; 95% CI, -3.06-0.65; P = .203) blood pressure. A prespecified subgroup analysis of studies with baseline systolic blood pressure ≥130 mm Hg revealed that a vegan diet resulted in a mean decrease in the systolic (-4.10 mm Hg; 95% CI, -8.14 to -0.06; P = .047) and diastolic (-4.01 mm Hg; 95% CI, -5.97 to -2.05; P = 0.000) blood pressures. CONCLUSION: The changes in blood pressure induced by a vegan diet without caloric restrictions are comparable with those induced by dietary approaches recommended by medical societies and portion-controlled diets.

Low Skeletal Muscle Mass Independently Predicts Mortality in Patients with Chronic Heart Failure after an Acute Hospitalization.

BACKGROUND: Heart failure (HF) is a syndrome associated with exercise intolerance, and its symptoms are more common in patients with low skeletal muscle mass (SMM). Estimation of muscle mass can be cumbersome and unreliable, particularly in patients with varying body weight. The psoas muscle area (PMA) can be used as a surrogate of sarcopenia and has been associated with poor outcomes in other populations. OBJECTIVES: The aim of this study was to assess if sarcopenia is associated with the survival of patients with HF after an acute hospitalization. METHOD: We retrospectively studied a cohort of 160 patients with HF who had abdominopelvic computed tomography during an acute hospitalization. We obtained standardized measurements of their PMA and defined sarcopenia as the lowest gender-based tertile of the said area. The patients were followed until death or discontinuation of care. We used Kaplan-Meier estimates and Cox regression analysis to assess the relationship between sarcopenia and all-cause mortality. RESULTS: We found that the 52 patients with sarcopenia had 4.5 times the risk of all-cause mortality at 1 year compared to the rest of the cohort (CI 1.784-11.765; p = 0.0016) after adjusting for significant covariates. Stratification by age and sex revealed that this association could be limited to males and patients < 75 years old. CONCLUSION: The PMA, used as a surrogate of low SMM, is independently associated with an increased risk of late mortality after an acute hospitalization in patients with HF.

Clinical outcomes of Β-blocker therapy in cocaine-associated heart failure.

BACKGROUND: Cocaine is associated with deleterious effects in the heart, including HFrEF. Although ß-blockers are recommended for this condition in other populations, their use is discouraged in cocaine users due to the possibility of exacerbating cocaine-related cardiovascular complications. This study was designed to determine if patients with heart failure and a reduced ejection fraction (HFrEF) who continue to use cocaine have better outcomes when they receive ß-blocker therapy than when they do not. METHODS: We performed a retrospective analysis of 72 ß-blocker-naïve patients with HFrEF and active cocaine use. Patients who were prescribed ß-blockers as part of their therapy were compared to those who were not, and clinical and structural outcomes were compared after 12 months of treatment. RESULTS: When patients with HFrEF and active cocaine use received ß-blocker therapy, they were more likely to have an improvement in their New York Heart Association functional class (p = 0.0106) and left ventricular ejection fraction (p = 0.0031) than when they did not receive ß-antagonists. In addition, the risk of cocaine-related cardiovascular events (p = 0.0086) and of heart failure hospitalizations (p = 0.0383) was significantly lower in patients who received ß-blockade than those who did not. CONCLUSIONS: ß-Blocker therapy is associated with improvement in the exercise tolerance and the left ventricular ejection fraction in patients with HFrEF and active cocaine use. They are also associated with a lower incidence of cocaine-related cardiovascular events and HFrEF-related readmissions.

Bare versus protected tetrairidium clusters by density functional theory.

The tetrairidium (Ir4) clusters are subnanometric systems vastly applied in catalysis, especially, because of the higher activity than mononuclear Ir complexes, intrinsic and controllable stability in relation to supports, and non-coalescence properties. The main catalytic properties of nanoclusters (activity and selectivity) are directly associated with their size, shape, and interactions with the environment, whose understanding requires study at the atomistic level. Here, the Ir4 clusters are studied considering the energetic stability for different chemical environments, bare versus protected, using density functional theory calculations within the generalized gradient approximation with van der Waals corrections and spin-orbit coupling, employing the all-electron projected augmented wave method. The square planar isomer is confirmed for the bare case as the lowest energy configuration considering semilocal and non-local exchange-correlation functionals, however, for different chemical environments (Ir4 protected by CO, O2, PH3, and SH2 ligands) the energy stability scenario is different; for CO, O2, and PH3 ligands the tetrahedron is the most stable isomer, in agreement with experimental insights, while for SH2 ligands the square motif is the most stable isomer. To improve the understanding of these systems, structural and electronic analysis were performed, in addition to energy decomposition analysis, to explore the bonding situation in Ir4 compounds. Our results showed an important relationship between the geometrical behavior and the nature and magnitude of Ir2Ir2 interactions, showing how the chemical environment affects the Ir4 nanoclusters. In general, the compounds with tetrahedron motifs showed a weakening of the σ and π bonds in relation to the square ones.

On the Development of Virtual Reality Scenarios for Computer-Assisted Biomedical Applications.

The modelling of virtual environments and scenarios is an important area of research for the development of new computer-assisted systems in the areas of engineering and medicine, particularly in the area of biomechanics and biomedical engineering. One of the main issues while designing a virtual environment is the level of realism, which depends on the computing capacity and the level of accuracy and usefulness of the generated data. Thus, the dilemma is between the aesthetic realism and the information utility. This paper proposes a methodology to develop low-cost and high-quality virtual environments and scenarios for computer-aided biomedical applications. The proposed methodology is based on the open-source software Blender and the Visualization Toolkit libraries (VTK). In order to demonstrate the usability of the proposed methodology, the design and development of a computer-assisted biomedical application is presented and analysed.

Improvement in clinical outcomes of patients with heart failure and active cocaine use after ß-blocker therapy.

BACKGROUND: Cocaine use has a high prevalence in the United States and can be associated with significant cardiovascular disease, even in asymptomatic users. ß-Adrenergic receptor hyperactivation is the underlying pathophysiologic pathway of cocaine cardiotoxicity. ß-Blocker therapy is controversial in patients with active cocaine use. HYPOTHESIS: ß-Blocker therapy is associated with clinical improvement in patients with heart failure despite active cocaine use. METHODS: In a single-center, retrospective chart analysis, patients with newly diagnosed heart failure and active cocaine use who had been started on ß-blocker therapy were reviewed. The New York Heart Association (NYHA) functional class and the left ventricular ejection fraction (LVEF) were recorded at baseline and after 12 monthsnthsnths of ß-blocker use. Patients were excluded if they had been on prior ß-blocker therapy, had other reasons for volume overload, had chronic kidney disease stages G4 or G5, or had a life expectancy <12 months. RESULTS: Thirty-eight patients were identified; most were African American males. A statistically significant improvement was found in both NYHA functional class (P < 0.0001) and LVEF (P < 0.0001) after 12 months of ß-blocker therapy. No major adverse cardiovascular events occurred in this population. CONCLUSIONS: ß-Blocker use in cocaine users with heart failure with a reduced ejection fraction is associated with a lower NYHA functional class and a higher LVEF at 12-month follow-up. No major adverse cardiovascular events were observed.

Tuning Heterocalixarenes to Improve Their Anion Recognition: A Computational Approach.

We have explored and analyzed the physical factors through which noncovalent interactions in anion sensing based on calixarene-type hosts can be tuned, using dispersion-corrected DFT and Kohn-Sham molecular orbital (KS-MO) theory in conjunction with a canonical energy decomposition analysis (EDA). We find that the host-guest interaction can be enhanced through the introduction of strongly electron-withdrawing groups at particular positions of the arene and triazine units in the host molecule as well as by coordination of a metal complex to the arene and triazine rings. Our analyses reveal that the enhanced anion affinity is caused by increasing the electrostatic potential in the heterocalixarene cavities. This insight can be employed to further tune and improve their selectivity for chloride ions.

Ultrastructural analysis of salivary glands in a phytophagous stink bug revealed the presence of unexpected muscles.

The exceptional abilities of stink bugs (Hemiptera: Pentatomidae) to colonize a diverse group of plants have been attributed to the feeding behaviors and the functions of the salivary complex of these insects. Here, we describe the ultrastructure of the salivary glands of the Neotropical brown stink bug, Euschistus heros, which is a major component of the pentatomid pest complex on soybeans, Glycine max, in the neotropics. Our results revealed a salivary gland complex consisting of two lobes (i.e., anterior and posterior), with a constriction between them (i.e., the hilum), in which the salivary and accessory gland ducts are inserted. The principal gland epithelium has a single layer of cells lining an enlarged lumen filled with saliva, and these cells are cuboidal, rich in rough endoplasmic reticulum and secretory vesicles, with well-developed nuclei, all of which are typical features of protein-secreting cells. We report, for the first time in insects, the presence of a layer of muscle cells surrounding the columnar hilum epithelium. The accessory salivary gland cells are cuboidal with nuclei containing condensed chromatin and cytoplasm rich in vacuoles and rough endoplasmic reticulum, indicating the potential involvement of these glands in water transport/secretion. The lumen content of each lobe of the principal gland suggests that the lobes produce different compounds. Thus, our results suggest that the E. heros salivary complex might have unconventional mechanisms to mix/release saliva, which might help explain the polyphagous abilities of these insects.

Competition between the phytophagous stink bugs Euschistus heros and Piezodorus guildinii in soybeans.

BACKGROUND: The abundance and contribution of the neotropical brown stink bug, Euschistus heros (F.), and the redbanded stink bug, Piezodorus guildinii (West.), to the composition of insect pests of soybean, Glycine max (L.), fields have changed both spatially and temporally in neotropical soybean production areas. Therefore, we assessed the competitiveness of each species in direct competition experiments following an additive series. We performed mixed (adult) insect infestations in soybean plants and evaluated the fitness of each species and the soybean yield. RESULTS: While the competitive ability of E. heros was significantly compromised by increments in conspecifics and heterospecifics (i.e. P. guildinii), the competitive ability of P. guildinii was compromised by the presence of heterospecifics (i.e. E. heros). The reproductive output of P. guildinii remained unaffected by increments in E. heros or of P. guildinii. Intriguingly, despite the fact that P. guildinii apparently lost the competition with E. heros, almost no pod production was observed in any plant colonised by the former. CONCLUSIONS: The higher abundance of E. heros in neotropical soybean fields seems to result from higher competitive ability than its heterospecific competitor P. guildinii, which may prevent the higher losses caused by P. guildinii. © 2016 Society of Chemical Industry.

Drug-Induced Subacute Cutaneous Lupus Erythematosus in a Patient Receiving Therapy for Chronic Hepatitis C.

Hepatitis C infection and its treatment have been associated with extrahepatic manifestations, including different skin conditions. Over the past decades, a greater number of drugs have been implicated as triggers for drug-induced subacute cutaneous lupus erythematosus. We report a case of a 42-year-old Hispanic man who developed a forehead violaceous rash during treatment with pegylated interferon alpha-2a as part of his therapy against hepatitis C infection that subsequently resulted to be subacute cutaneous lupus erythematosus. The skin lesion improved with discontinuation of medication and some topic therapy.

Assessment of clinical occupational dose reduction effect of a new interventional cardiology shield for radial access combined with a scatter reducing drape.

OBJECTIVES: To assess the occupational dose reduction effect of a new interventional cardiology shield for radial access combined with a scatter reducing drape. BACKGROUND: Transradial access for catheterization has been shown to increase occupational radiation dose. Current shielding techniques are primarily based on the femoral access. This article looks at the clinical occupational combined dose reduction effect of a commercially available shield and drape which is specific to access type. METHODS: The evaluation took place in a busy interventional cardiology laboratory, with a single plane 30×40 cm flat panel detector (Siemens Artis Zee, Germany). Radiation exposure to staff was measured using electronic personal dosimeters (Unfors RaysafeAB, Sweden) placed at the collar. Patient radiation exposure was assessed using screening time and dose area product per case. Both staff and patient radiation exposure were monitored for a number of case types and operators before, during, and after deployment of the new shield and drapes. RESULTS: The cardiologists' overall median collar badge reading per case reduced from 15.4 µSv per case without the shield/drape combination to 7.3 µSv per case with the shield drape combination in situ (P<0.001). The radiographers badge reading was reduced from 4.2 µSv per case without to 2.5 µSv per case with the shield drape combination in situ (P<0.001). There was no statistical difference in the cardiac technician's badge reading. Patient's dose area product was not significantly affected by the placement of the shield and drape combination. CONCLUSIONS: The shield/drape combination can significantly reduce operator exposure in a cardiac catheterization laboratory.