bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Loss Nanostructured Polymers for Chip-scale Waveguide Amplifiers
Authors: Chen George F. R. , Zhao Xinyu , Sun Yang , He Chaobin , Tan Mei Chee , Tan Dawn T. H. 
Published: June 2017

AbstractOn-chip waveguide amplifiers offer higher gain in small device sizes and better integration with photonic devices than the commonly available fiber amplifiers. However, on-chip amplifiers have yet to make its way into the mainstream due to the limited availability of materials with ideal light guiding and amplification properties. A low-loss nanostructured on-chip channel polymeric waveguide amplifier was designed, characterized, fabricated and its gain experimentally measured at telecommunication wavelength. The active polymeric waveguide core comprises of NaYF4:Yb,Er,Ce core-shell nanocrystals dispersed within a SU8 polymer, where the nanoparticle interfacial characteristics were tailored using hydrolyzed polyhedral oligomeric silsesquioxane-graft-poly(methyl methacrylate) to improve particle dispersion. Both the enhanced IR emission intensity from our nanocrystals using a tri-dopant scheme and the reduced scattering losses from our excellent particle dispersion at a high solid loading of 6.0 vol% contributed to the outstanding optical performance of our polymeric waveguide. We achieved one of the highest reported gain of 6.6 dB/cm using a relatively low coupled pump power of 80 mW. These polymeric waveguide amplifiers offer greater promise for integrated optical circuits due to their processability and integration advantages which will play a key role in the emerging areas of flexible communication and optoelectronic devices.
Label-free imaging of bone multiscale porosity and interfaces using third-harmonic generation microscopy
Authors: Genthial Rachel , Beaurepaire Emmanuel , Schanne-Klein Marie-Claire , Peyrin Françoise , Farlay Delphine , Olivier Cécile , Bala Yohann , Boivin Georges , Vial Jean-Claude , Débarre Delphine , Gourrier Aurélien 
Published: June 2017

AbstractInterfaces provide the structural basis of essential bone functions. In the hierarchical structure of bone tissue, heterogeneities such as porosity or boundaries are found at scales ranging from nanometers to millimeters, all of which contributing to macroscopic properties. To date, however, the complexity or limitations of currently used imaging methods restrict our understanding of this functional integration. Here we address this issue using label-free third-harmonic generation (THG) microscopy. We find that the porous lacuno-canalicular network (LCN), revealing the geometry of osteocytes in the bone matrix, can be directly visualized in 3D with submicron precision over millimetric fields of view compatible with histology. THG also reveals interfaces delineating volumes formed at successive remodeling stages. Finally, we show that the structure of the LCN can be analyzed in relation with that of the extracellular matrix and larger-scale structures by simultaneously recording THG and second-harmonic generation (SHG) signals relating to the collagen organization.
Satellite tagging of Mediterranean fin whales: working towards the identification of critical habitats and the focussing of mitigation measures
Authors: Panigada Simone , Donovan Gregory P. , Druon Jean-Noël , Lauriano Giancarlo , Pierantonio Nino , Pirotta Enrico , Zanardelli Margherita , Zerbini Alexandre N. , di Sciara Giuseppe Notarbartolo 
Published: June 2017

AbstractMediterranean fin whales comprise a genetically distinct population, listed as Vulnerable (VU) in the IUCN Red List. Collisions with vessels are believed to represent the main cause of human-induced mortality. The identification of critical habitats (including migration routes) incorporating satellite telemetry data is therefore crucial to develop focussed conservation efforts. Between 2012 and 2015 thirteen fin whales were equipped with satellite transmitters, 8 in the Pelagos Sanctuary (although two ceased within two days) and 5 in the Strait of Sicily, to evaluate movements and habitat use. A hierarchical switching state-space model was used to identify transiting and area-restricted search (ARS) behaviours, believed to indicate foraging activities. All whales undertook mid- to long-distance migrations, crossing some of the world’s busiest maritime routes. Areas where the animals predominantly engaged in ARS behaviour were identified in both study areas. The telemetry data were compared with results from ecosystem niche modelling, and showed that 80% of tagged whale positions was near (<7 km) the closest suitable habitat. The results contribute to the view that precautionary management should include establishment of a coordinated and dynamic basin-wide management scheme; if appropriate, this may include the establishment of protected areas by specific regional Conventions.
A Guide to Design Functional Molecular Liquids with Tailorable Properties using Pyrene-Fluorescence as a Probe
Authors: Lu Fengniu , Takaya Tomohisa , Iwata Koichi , Kawamura Izuru , Saeki Akinori , Ishii Masashi , Nagura Kazuhiko , Nakanishi Takashi 
Published: June 2017

AbstractSolvent-free, nonvolatile, room-temperature alkylated-π functional molecular liquids (FMLs) are rapidly emerging as a new generation of fluid matter. However, precision design to tune their physicochemical properties remains a serious challenge because the properties are governed by subtle π-π interactions among functional π-units, which are very hard to control and characterize. Herein, we address the issue by probing π-π interactions with highly sensitive pyrene-fluorescence. A series of alkylated pyrene FMLs were synthesized. The photophysical properties were artfully engineered with rational modulation of the number, length, and substituent motif of alkyl chains attached to the pyrene unit. The different emission from the excimer to uncommon intermediate to the monomer scaled the pyrene-pyrene interactions in a clear trend, from stronger to weaker to negligible. Synchronously, the physical nature of these FMLs was regulated from inhomogeneous to isotropic. The inhomogeneity, unexplored before, was thoroughly investigated by ultrafast time-resolved spectroscopy techniques. The result provides a clearer image of liquid matter. Our methodology demonstrates a potential to unambiguously determine local molecular organizations of amorphous materials, which cannot be achieved by conventional structural analysis. Therefore this study provides a guide to design alkylated-π FMLs with tailorable physicochemical properties.
Isothiocyanates are detected in human synovial fluid following broccoli consumption and can affect the tissues of the knee joint
Authors: Davidson Rose , Gardner Sarah , Jupp Orla , Bullough Angela , Butters Sue , Watts Laura , Donell Simon , Traka Maria , Saha Shikha , Mithen Richard , Peffers Mandy , Clegg Peter , Bao Yongping , Cassidy Aedin , Clark Ian 
Published: June 2017

AbstractOsteoarthritis is a major cause of disability and there is no current pharmaceutical treatment which can prevent the disease or slow its progression. Dietary advice or supplementation is clearly an attractive option since it has low toxicity and ease of implementation on a population level. We have previously demonstrated that sulforaphane, a dietary isothiocyanate derived from its glucosinolate precursor which is found in broccoli, can prevent cartilage destruction in cells, in in vitro and in vivo models of osteoarthritis. As the next phase of this research, we enrolled 40 patients with knee osteoarthritis undergoing total knee replacement into a proof-of-principle trial. Patients were randomised to either a low or high glucosinolate diet for 14 days prior to surgery. We detected ITCs in the synovial fluid of the high glucosinolate group, but not the low glucosinolate group. This was mirrored by an increase in ITCs and specifically sulforaphane in the plasma. Proteomic analysis of synovial fluid showed significantly distinct profiles between groups with 125 differentially expressed proteins. The functional consequence of this diet will now be tested in a clinical trial.
Dynamic Nuclear Polarization NMR as a new tool to investigate the nature of organic compounds occluded in plant silica particles
Authors: Masion Armand , Alexandre Anne , Ziarelli Fabio , Viel Stéphane , Santos Guaciara M. 
Published: June 2017

AbstractThe determination of the chemical nature of the organic matter associated with phytoliths remains a challenge. This difficulty mainly stems from amounts of organic carbon (C) that are often well below the detection limit of traditional spectroscopic tools. Conventional solid-state 13C Nuclear Magnetic Resonance (NMR) is widely used to examine the nature and structure of organic molecules, but its inherent low sensitivity prohibits the observation of diluted samples. The recent advent of commercial microwave source in the terahertz range triggered a renewed interest in the Dynamic Nuclear Polarization (DNP) technique to improve the signal to noise ratio of solid-state NMR experiments. With this technique, the 13C spectrum of a phytolith sample containing 0.1% w/w C was obtained overnight with sufficient quality to permit a semi-quantitative analysis of the organic matter, showing the presence of peptides and carbohydrates as predominant compounds. Considering the natural abundance of the 13C isotope, this experiment demonstrates that DNP NMR is sufficiently sensitive to observe spin systems present in amounts as low as a few tens of ppm.
Time‐division polynomial pre‐distorter for linearisation of 1.5 T MRI power amplifier
Authors: Hui Ming , Zhang Meng , Zhang Xingang , Zhu Xiaowei , Zhang Xiupu , Cheng Jiali 
Published: June 2017

A time‐division polynomial (TDP) model is proposed for modelling and linearising a 1.5 T magnetic resonance imaging (MRI) power amplifier (PA) with strong non‐linearity in high input signal dynamic range. In order to demonstrate the merit of this non‐linear model, a 64 dBm 1.5 T MRI PA (63.89 MHz) and two different Sinc‐pulse signals are used in modelling and linearisation measurements. The TDP is compared with the conventional non‐memory polynomial (NMP) and no digital pre‐distortion for the 1.5 T MRI PA, which is driven by test signal with 2 ms time length and 2% duty cycle. The proposed TDP leads to up to 9 dB improvement in the normalised mean square error compared with the NMP in two different test signals. More importantly, TDP illustrates significantly better reduction in amplitude modulation/amplitude modulation (AM/AM) and amplitude modulation/phase modulation (AM/PM) conversion compared with the NMP.
Using Ventilator-Associated Pneumonia Rates as a Health Care Quality Indicator: A Contentious Concept
Authors: Nair Girish , Niederman Michael 
Published: June 2017

AbstractPneumonia is a leading cause of hospital-acquired infections, although reported rates of ventilator-associated pneumonia (VAP) have been declining in recent years. A multifaceted infection prevention approach, using a “ventilator bundle,” has been shown to reduce the frequency of VAP, while improving other patient outcomes. Because of difficulties in defining VAP, the Center for Medicare and Medicaid Service introduced a new streamlined ventilator-associated event (VAE) definition in 2013 for the surveillance of complications in mechanically ventilated patients. VAE measures are increasingly being measured by institutions in the United States in place of VAP rates and as a potential measure of the quality of intensive care unit (ICU) care. However, there is increased recognition that the streamlined definitions identify a different subset of patients than those identified by traditional VAP surveillance and that VAP prevention strategies may not impact all the causes of VAE. Also, VAP and VAE rates may not always reflect the quality of care in a given ICU, especially since patient factors, beyond the control of the hospital, may impact the rates of VAP and VAE. In this review, we discuss the issues related to VAP as a quality measure and the areas of uncertainty related to the new VAE definitions.
Should We Immediately Start Antibiotics in Every Patient with a Clinical Suspicion of HAP/VAP?
Authors: Hassinger Taryn , Sawyer Robert 
Published: June 2017

AbstractHospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) remain two of the most commonly diagnosed nosocomial infections. Both are responsible for significant morbidity and mortality in hospitalized patients. The development of HAP and VAP is related to bacterial colonization of the oropharynx (and endotracheal tube in VAP) with subsequent microaspiration and development of clinical infection. Diagnosis is made based on the clinical presentation and can be confirmed by obtaining either noninvasive or invasive microbiology culture specimens. Decisions addressing initiation of antimicrobial therapy can be divided into clinical and bacteriological strategies. These strategies differ in the criteria used to determine the timing of empiric therapy, with the clinical strategy basing the decision on radiographic evidence of infection plus clinical signs and symptoms and the bacteriological strategy requiring growth of pathogens above a certain threshold from invasively obtained culture specimens. Despite the delineated pathways, these decisions remain multifactorial and should also include consideration of patient-related factors, such as immunocompetence, the risk of multidrug-resistant infection, and overall clinical condition. Patients with risk factors or signs of clinical decompensation should have empiric therapy initiated at a lower threshold. However, when possible, therapy should be directed at a confirmed infection following a positive culture result. Decisions regarding specific empiric regimens should be based on the local prevalence of infectious microorganisms along with their associated antimicrobial susceptibilities. Patients deemed at risk of infection with multidrug-resistant pathogens merit broader spectrum therapy, and immunosuppressed patients should have consideration of antifungal coverage.
Emergence of Antimicrobial Resistance among Pseudomonas aeruginosa: Implications for Therapy
Authors: Zhanel George , Clark Nina , Lynch Joseph 
Published: June 2017

Abstract
Pseudomonas aeruginosa (PA), a nonlactose fermenting gram-negative bacillus, is a common cause of nosocomial infections in critically ill or debilitated patients, particularly ventilator-associated pneumonia (VAP), and infections of bloodstream, urinary tract, intra-abdominal, wounds/skin/soft tissue. PA rarely affects healthy individuals, but may cause serious infections in patients with chronic structural lung disease, comorbidities, advanced age, impaired immune defenses, or with medical devices (e.g., urinary or intravascular catheters, foreign bodies). Treatment of pseudomonal infections is difficult, as PA is intrinsically resistant to multiple antimicrobials, and may acquire new resistance determinants even while on antimicrobial therapy. Mortality associated with pseudomonal VAP or bacteremias is high (> 35%) and optimal therapy is controversial. Over the past three decades, antimicrobial resistance among PA has escalated globally, via dissemination of several international multidrug-resistant “epidemic” clones. We review the emergence of antimicrobial resistance to this pathogen, and discuss approaches to therapy (both empirical and definitive).
Oropharyngeal Decontamination with Antiseptics to Prevent Ventilator-Associated Pneumonia: Rethinking the Benefits of Chlorhexidine
Authors: Klompas Michael 
Published: June 2017

AbstractDaily oral care with chlorhexidine for mechanically ventilated patients is ubiquitous in contemporary intensive care practice. The practice is predicated upon meta-analyses suggesting that adding chlorhexidine to daily oral care regimens can reduce ventilator-associated pneumonia (VAP) rates by up to 40%. Close analysis, however, raises three concerns: (1) the meta-analyses are dominated by studies in cardiac surgery patients in whom average duration of mechanical ventilation is < 1 day and thus their risk of VAP is very different from other populations, (2) diagnosing VAP is subjective and nonspecific yet the meta-analyses gave equal weight to blinded and nonblinded studies, potentially biasing them in favor of chlorhexidine, and (3) there is circularity between diagnostic criteria for VAP and chlorhexidine; as an antiseptic, chlorhexidine may decrease the frequency of positive respiratory cultures but fewer cultures does not necessarily mean fewer pneumonias. It is therefore important to look at other outcomes for corollary evidence on whether or not oral chlorhexidine benefits patients. An updated meta-analysis restricted to double-blinded studies in noncardiac surgery patients showed no impact on VAP rates, duration of mechanical ventilation, or intensive care unit length of stay. Instead, there was a possible signal that oral chlorhexidine may increase mortality rates. Observational data have raised similar concerns. This article will review the theoretical basis for adding chlorhexidine to oral care regimens, delineate potential biases in randomized controlled trials comparing oral care regimens with and without chlorhexidine, explore the unexpected mortality signal associated with oral chlorhexidine, and provide practical recommendations.
How Should We Treat HAP/VAP Caused by Carbapenemase-Producing Enterobacteriaceae?
Authors: Peghin Maddalena , Carnelutti Alessia , Righi Elda , Bassetti Matteo 
Published: June 2017

AbstractHospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) represent a common problem in hospital setting worldwide. Infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are an emergent problem due to the lack of therapeutic options available, leading to significant increases in morbidity and mortality. CRE have frequently been reported both in HAP/VAP, but limited data regarding the optimal treatment strategy in this setting are available. This review focuses on the current epidemiology of CRE, with a specific focus on HAP/VAP. Moreover, we will suggest a possible strategy for the empiric and targeted treatment of HAP and VAP in which the involvement of CRE is suspected or is confirmed.
New Strategies Targeting Virulence Factors of Staphylococcus aureus and Pseudomonas aeruginosa
Authors: François Bruno , Luyt Charles-Edouard , Stover C. , Brubaker Jeffery , Chastre Jean , Jafri Hasan 
Published: June 2017

AbstractMorbidity, mortality, and economic burden of nosocomial pneumonia caused by Staphylococcus aureus and Pseudomonas aeruginosa remain high in mechanically ventilated and hospitalized patients despite the use of empirical antibiotic therapy or antibiotics against specific classes of pathogens and procedures to reduce nosocomial infections in hospital settings. Newer agents that neutralize or inhibit specific S. aureus or P. aeruginosa virulence factors may eliminate or reduce the risk for developing pneumonia before or during mechanical ventilation and may improve patient outcomes through mechanisms that differ from those of antibiotics. In this article, we review the types, mechanisms of action, potential advantages, and stage of development of antivirulence agents (AVAs) that hold promise as alternative preventive or interventional therapies against S. aureus– and P. aeruginosa–associated nosocomial pneumonias. We also present and discuss challenges to the effective utilization of AVAs separately from or in addition to antibiotics and the design of clinical trials and meaningful study end points.
Pharmacokinetic/Pharmacodynamics-Optimized Antimicrobial Therapy in Patients with Hospital-Acquired Pneumonia/Ventilator-Associated Pneumonia
Authors: Sulaiman Helmi , Abdul-Aziz Mohd , Roberts Jason 
Published: June 2017

AbstractHospital-acquired pneumonia and ventilator-associated pneumonia continue to cause significant morbidity and mortality. With increasing rates of antimicrobial resistance, the importance of optimizing antibiotic treatment is key to maximize treatment outcomes. This is especially important in critically ill patients in intensive care units, in whom the infection is usually caused by less susceptible organisms. In addition, the marked physiological changes that can occur in these patients can cause serious changes in antibiotic pharmacokinetics which in turn alter the attainment of therapeutic drug exposures. This article reviews the various aspects of the pharmacokinetic changes that can occur in the critically ill patients, the barriers to achieving therapeutic drug exposures in pneumonia for systemically delivered antibiotics, the optimization for commonly used antibiotics in hospital- and ventilator-associated pneumonia, the agents that should be avoided in the treatment regimen, as well as the use of adjunctive therapy in the form of nebulized antibiotics.
Is There a Role for Inhaled Antibiotics in the Treatment of Ventilator-Associated Infections?
Authors: Rello Jordi , Palmer Lucy 
Published: June 2017

AbstractThe increasing emergence of multidrug-resistant organisms creates a therapeutic challenge for physicians treating ventilator-associated respiratory infections. As the production of new systemic antibiotics lags far behind the emergence of worsening antibiotic resistance, intensivists are turning to inhaled antibiotics to use as adjunctive therapy. When given properly, these drugs can provide high concentrations of drug in the lung that could not be achieved with intravenous antibiotics without significant systemic toxicity. This review summarizes current evidence describing the use of inhaled antibiotics for the treatment of bacterial ventilator-associated infections. Inhaled adjunctive therapy has been described in numerous small nonrandomized studies and in six recent randomized placebo-controlled trials. Inhaled therapy has also been used to treat ventilator-associated tracheobronchitis. These preliminary data suggest aerosolized delivery of antimicrobials may effectively treat resistant pathogens with high minimum inhibitory concentrations when used in time-limited protocols and delivered with devices known to deposit antibiotics in the area of infection. Large, multisite, clinical, randomized placebo-controlled studies are needed to confirm these data.
Body Position and Ventilator-Associated Pneumonia Prevention
Authors: Xiol Eli , Pagliara Francesco , Hua Yang , Torres Antoni , Bassi Gianluigi 
Published: June 2017

AbstractSeminal studies have demonstrated that tracheally intubated, mechanically ventilated patients, positioned in supine horizontal position, are at a high risk of developing ventilator-associated pneumonia, through aspiration of gastric pathogens. In the 1990s, innovative clinical findings promoted a radical change in practice, through the use of the semirecumbent position in all mechanically ventilated patients. Here, we critically review the main indications, pulmonary effects, and controversies on the use of the semirecumbent position. Also, we will depict potential roles of prone and lateral positions in the prevention of ventilator-associated pneumonia. Our review will span from preclinical experimental insights to clinical evidence, and we will discuss potential controversies on the use of the semirecumbent position as the standard of care. We will also detail potential alternatives to ultimately improve outcomes of tracheally intubated and mechanically ventilated patients.