959 research outputs found

    Flame spray synthesis under a non-oxidizing atmosphere: Preparation of metallic bismuth nanoparticles and nanocrystalline bulk bismuth metal

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    Metallic bismuth nanoparticles of over 98% purity were prepared by a modified flame spray synthesis method in an inert atmosphere by oxygen-deficient combustion of a bismuth-carboxylate based precursor. The samples were characterized by X-ray diffraction, thermal analysis and scanning electron microscopy confirming the formation of pure, crystalline metallic bismuth nanoparticles. Compression of the as-prepared powder resulted in highly dense, nanocrystalline pills with strong electrical conductivity and bright metallic glos

    A Characterization of the DNA Data Storage Channel

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    Owing to its longevity and enormous information density, DNA, the molecule encoding biological information, has emerged as a promising archival storage medium. However, due to technological constraints, data can only be written onto many short DNA molecules that are stored in an unordered way, and can only be read by sampling from this DNA pool. Moreover, imperfections in writing (synthesis), reading (sequencing), storage, and handling of the DNA, in particular amplification via PCR, lead to a loss of DNA molecules and induce errors within the molecules. In order to design DNA storage systems, a qualitative and quantitative understanding of the errors and the loss of molecules is crucial. In this paper, we characterize those error probabilities by analyzing data from our own experiments as well as from experiments of two different groups. We find that errors within molecules are mainly due to synthesis and sequencing, while imperfections in handling and storage lead to a significant loss of sequences. The aim of our study is to help guide the design of future DNA data storage systems by providing a quantitative and qualitative understanding of the DNA data storage channel

    Physico-Chemical Differences Between Particle- and Molecule-Derived Toxicity: Can We Make Inherently Safe Nanoparticles?

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    The rapidly growing applications of nanotechnology require a detailed understanding of benefits and risks, particularly in toxicology. The present study reviews the physical and chemical differences between particles and molecules when interacting with living organisms. In contrast to classical chemicals, the mobility of nanoparticles is governed by agglomeration, a clustering process that changes the characteristic size of the nanomaterials during exposure, toxicity tests or in the environment. The current status of nanotoxicology highlights non-classical toxic interactions through catalytic processes inside living cells and the enhanced heavy metal transport into the cytosol through the 'Trojan horse mechanism'. The safety of nanoparticles in consumer goods is proposed to be rendered inherently safer by substituting the currently used persistent oxides through biodegradable materials

    Is standardized care feasible in the emergency setting? A case matched analysis of patients undergoing laparoscopic cholecystectomy.

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    Immediate laparoscopic cholecystectomy is the accepted standard for the treatment of acute cholecystitis. The aim of the present study was to evaluate the feasibility of a standardized approach with tailored care maps for pre- and postoperative care by comparing pain, nausea and patient satisfaction after elective and emergent laparoscopic cholecystectomy. From January 2014 until April 2015, data on pain and nausea management were prospectively recorded for all elective and emergency procedures in the department of visceral surgery. This prospective observational study compared consecutive laparoscopic elective vs. emergency cholecystectomies. Visual analogue scales (VAS) were used to measure pain, nausea, and satisfaction from recovery room until 96 hours postoperatively. Final analysis included 168 (79%) elective cholecystectomies and 44 (21%) emergent procedures. Demographics (Age, gender, BMI and ASA-scores) were comparable between the 2 groups. In the emergency group, patients did not receive anxiolytic medication (0% vs.13%, p = 0.009) and less postoperative nausea and vomiting (PONV) prophylaxis (77% vs. 97% p = <0.001). Perioperative pain management was similar in terms of opioid consumption (median amount of fentanyl 450ug [IQR 350-500] vs. 450ug [375-550], p = 0.456) and wound infiltration rates (24% vs. 25%, p = 0.799). Postoperative consumption of paracetamol, metamizole and opiod medications were similar between the 2 groups. VAS scores for pain (p = 0.191) and nausea (p = 0.392) were low for both groups. Patient satisfaction was equally high in both clinical settings (VAS 8.5 ± 1.1 vs. 8.6 ± 1.1, p = 0.68). A standardized pathway allows equally successful control of pain and nausea after both elective and emergency laparoscopic cholecystectomy. This study was retrospectively registered by March 01, 2016 in the following trial register: www.researchregistry.com (UIN researchregistry993)

    Impact of weekday surgery on application of enhanced recovery pathway: a retrospective cohort study.

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    To compare the enhanced recovery after surgery (ERAS) protocol compliance and clinical outcomes depending on the weekday of surgery. Cohort of consecutive non-selected patients undergoing elective colorectal surgery from January 2012 to March 2015. This retrospective analysis of our prospective database compared patients operated early in the week (Monday and Tuesday) with patients operated in the second half (late: Thursday, Friday). Compliance with the ERAS protocol, functional recovery, complications and length of stay. Demographic and surgical details were similar between the early (n=352) and late groups (n=204). Overall compliance with the ERAS protocol was 78% vs 76% for the early and late groups, respectively (p=0.009). Significant differences were notably prolonged urinary drainage and intravenous fluid infusion in the late group. Complication rates and length of stay, however, were not different between surgery on Monday or Tuesday and surgery on Thursday or Friday. Application of the ERAS protocol showed only minor differences for patients operated on early or late during the week, and clinical outcomes were similar. A fully implemented ERAS programme appears to work also over the weekend

    Advanced piezoresistance of extended metal/insulator core shell nanoparticle assemblies

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    Assembled metal/insulator nanoparticles with a core/shell geometry provide access to materials containing a large number (>106) of tunneling barriers. We demonstrate the production of ceramic coated metal nanoparticles exhibiting an exceptional pressure sensitive conductivity. We further show that graphene bi- and trilayers on 20 nm copper nanoparticles are insulating in such core/shell geometry and show a similar pressure dependent conductivity. This demonstrates that core/shell metal/insulator assemblies offer a route to alternative sensing materials.Comment: 14 pages, 3 figures, published in Physical Review Letter

    Pain Intensity in the First 96 Hours After Abdominal Surgery: A Prospective Cohort Study.

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    Multimodal pain management strategies aim to improve postoperative pain control. The purpose of this study was to analyze pain scores and risk factors for acute postoperative pain after various abdominal surgery procedures. Data on 11 different abdominal surgery procedures were prospectively recorded. Pain intensity (rest, mobilization) and patient satisfaction at discharge were assessed using a visual analog scale (VAS; 0-10), and analgesic consumption was recorded until 96 hours postoperation. Demographic, surgery-related, and pain management-related univariate risk factors for insufficient pain control (VAS ≥ 4) were entered in a multivariate logistic regression model. A total of 1,278 patients were included. Overall, mean VAS scores were <3 at all time points, and scores at mobilization were consistently higher than at rest (P < 0.05). Thirty percent of patients presented a prolonged VAS score ≥4 at mobilization at 24 hours, significantly higher than at rest (14%, P < 0.05). High pain scores correlated with high opioid consumption, whereas a variability of pain scores was observed in patients with low opioid consumption. The only independent risk factor for moderate and severe pain (VAS ≥ 4) was younger age (<70 years, P = 0.001). The mean satisfaction score was 8.18 ± 1.29. Among 1,278 patients, pain was controlled adequately during the first four postoperative days, resulting in high levels of patient satisfaction. Pain levels were higher at mobilization. Younger age was the only independent risk factor for insufficient pain control. Preventive treatment in patients <70 years old and before mobilization could be evaluated for potential improvement

    Preoperative Nutritional Conditioning of Crohn's Patients-Systematic Review of Current Evidence and Practice.

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    Crohn's disease is an incurable and frequently progressive entity with major impact on affected patients. Up to half of patients require surgery in the first 10 years after diagnosis and over 75% of operated patients require at least one further surgery within lifetime. In order to minimize surgical risk, modifiable risk factors such as nutritional status need to be optimized. This systematic review on preoperative nutritional support in adult Crohn's patients between 1997 and 2017 aimed to provide an overview on target populations, screening modalities, routes of administration, and expected benefits. Pertinent study characteristics (prospective vs. retrospective, sample size, control group, limitations) were defined a priori. Twenty-nine studies were retained, of which 14 original studies (9 retrospective, 4 prospective, and 1 randomized controlled trial) and 15 reviews. Study heterogeneity was high regarding nutritional regimens and outcome, and meta-analysis could not be performed. Most studies were conducted without matched control group and thus provide modest level of evidence. Consistently, malnutrition was found to be a major risk factor for postoperative complications, and both enteral and parenteral routes were efficient in decreasing postoperative morbidity. Current guidelines for nutrition in general surgery apply also to Crohn's patients. The route of administration should be chosen according to disease presentation and patients' condition. Further studies are needed to strengthen the evidence
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