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Postoperative wound infections represent an important source of morbidity and mortality in children. Perioperative antibiotic prophylaxis has been shown to decrease the risk of developing infections and hospital guidelines surrounding antibiotic use exist to standardize patient care. Despite supporting evidence, rates of compliance with guidelines vary. Quality improvement initiatives have been introduced to improve compliance with intraoperative antibiotic guidelines. Thorough infection surveillance, including antibiotic provision in presurgical checklists, computerized voice antibiotic administration prompts, and national feedback systems are now increasingly common. Few studies have been conducted investigating the effectiveness of prophylactic antibiotics in children. Outcome measures such as morbidity and mortality and return to the operating room can be used to examine the relationship between antibiotic use and patient outcome but these measures are limited in that they occur infrequently or are subjective and difficult to measure. Metrics such as days alive out of hospital and length of hospital stay may be useful alternatives for ongoing monitoring of infections and identifying improvements in patient outcomes. Guidelines on antibiotic prophylaxis have facilitated an increase in the correct provision of perioperative antibiotics and a reduction in the incidence of postoperative infection. Measures of patient outcome such as days alive out of hospital and length of hospital stay are easy to collect and calculate but further work is needed to confirm the utility of these measures for monitoring infection rates.

This chapter examines the hermeneutical strategies taken by early Christian authors with respect to the law of Moses. It considers the two other laws most often discussed by patristic authors, the natural law and the law of Christ, only in relation to that law. This chapter shows how early mainstream Christian treatments of the Mosaic law were shaped decisively by ongoing polemics against Judaism and dualist instantiations of Christianity. It contends that though early Christian interpretation of the Mosaic law was certainly not uniform in regard to theological emphases and exegetical tactics, the pressure exerted by these two polemical contexts had a standardizing effect, insofar as virtually all patristic authors both relativized the value of the law vis-à-vis Judaism and affirmed its relative and absolute goodness over against dualist critiques.

The Polymer Electrolyte Membrane Fuel Cells (PEMFCs) platinum catalyst’s susceptibility to poisoning by carbon monoxide (CO) reduces its output power. In an effort to diminish poisoning, gold and platinum nanoparticles were incorporated onto partially reduced graphene oxide (Au/Pt-prGO) sheets to reduce both nanoparticle aggregation and the amount of precious metal needed. Applying this material onto the electrodes and Nafion membrane of a PEMFC was hypothesized to increase CO tolerance as well as power output. Aliquots of graphene oxide (GO) were functionalized with platinum and/or gold nanoparticles using a simple desktop synthesis at room temperature. Partial reduction with NaBH4 maintained hydrophilic solubility. Test solutions applied to electrodes and to electrodes + Nafion membrane were first tested in a PEM fuel cell with a pure H2 gas feed and then repeated with a H2 gas feed containing 1000 ppm of CO. Test arrangements averaged doubling the output power of the poisoned control, with the most effective yielding an output power ∼250% that of the poisoned control. Additionally, each system’s poisoned output power (PP) was compared to its highest possible output power (PM), with the most effective setup showing no reduction in output power, even with a H2 gas feed containing 1000 ppm of CO. Thus, this offers promise of a simple, cost-effective method of both improving PEMFC power output while reducing or even eliminating CO poisoning at room temperature.

While graphene has unique electrical and mechanical properties, it is not soluble in most common solvents. Partially reducing graphene oxide (prGO) will remove some of the functional groups while still maintaining solubility, producing an intermediate between graphene oxide and reduced graphene oxide. This research investigated the properties of prGO as well as those of prGO sheets incorporated with gold and platinum nanoparticles (Au/Pt-prGO) using FTIR, Raman, TEM and HRTEM.

With the demand for precise nanometric material removal with minimal defects, several non-contact ultraprecision machining techniques were developed over recent decades. The electrokinetic material removal technique [1] is one such method that allows material to be removed without any physical contact between the tool and the workpiece. In this work, the influence of the slurry mixture on the material removal rate for the electrokinetic material removal process is studied. During the process, it was observed experimentally that the mixture of the slurry affected the material removal rate. The parameters varied in the slurry mixture experiments were the size and concentration of the particles. Explanations for the behaviour of the material removal rate were also suggested during the study to further understand the electrokinetic material removal technique.

Non-contact material removal processes offer numerous advantages over traditional machining approaches and nowhere is this more apparent than in the fabrication of micro devices. Current micromachining techniques such as microgrinding and micromilling have limitations with respect to their positioning accuracy and tool deflections. Electro thermal processes such as microEDM and laser machining usually result in a heat affected zone being produced. Other approaches such as etching and non-contact ultraprecision polishing are either costly or are not suitable for high throughput. In order to address these limitations, alternative micromachining techniques are required. In this paper, a non-contact material removal technique based on the electrokinetic phenomenon is proposed for precise material removal at rates in the order of nanometers/min. The aim of this research is to have a better understanding on the electrokinetic material removal technique by studying the trajectory of the particles and the influence of the frequency of the electric field on the material removal rate.

We have previously reported on a simple desktop method for producing high quality reduced graphene oxide sheets (RGO) which involved dispersing graphene oxide in an ethanol-water solvent and reducing it with sodium borohydride. Metal salts can also be potent reducing agents. Here we show that when these salts are incorporated into the reduction process, metalized graphene sheets can be formed. Metallic salts were used to form Au, Pt, and AuPt nanoplatelets incorporated into the graphene structure. The nature of these metalized graphene platelets was then examined using FTIR, TEM, and SEM/EDAX. Raman spectroscopy of metalized graphene samples show peak shifts and increased D/G ratios over pure graphene, indicating an increased number of defects in the material and suggesting an attachment of metal atoms to the graphene surface. By using a minimum of metal while maximizing the surface contact area of the graphene sheet, these nanoparticle-RGO composites have potential for use in energy-producing devices and/or as catalysts.

SummaryAims Clonidine may be used intraoperatively to decrease emergence delirium in children, but the drug's impact on postoperative sedation is poorly quantified. Methods A prospective audit of children (≤15 years) undergoing (adeno) tonsillectomy or adenoidectomy over a period of 4 months was carried out. All children received sevoflurane for induction and maintenance of anesthesia. The use of clonidine as an adjunct was left to the discretion of the anesthesiologist. Postoperative sedation was assessed using the University of Michigan Sedation Scale (UMSS) at 30 min intervals until discharge. Arousal was characterized using a zero asymptote model. The impact of clonidine dose on half-time to an awake state after anesthesia was investigated using nonlinear mixed effects models. Survival analysis was used to explore the effect of clonidine dose on discharge time. Results The mean age of children (n = 177) was 5.4 sd 3.3 years, range 0.8–15.0 years and weight was 23.8 sd 11.4 kg, range 10.0–76.4 kg. There were 73 children given clonidine 0.29–4.80 mcg·kg−1 after induction. The half-time to emergence was 10.8 (95% CI 8.5, 13.2) min. Emergence half-time was increased to 15 min with clonidine 0.5 mcg·kg−1, 20 min with clonidine 1.5 mcg·kg−1, 25 min with clonidine 2 mcg·kg−1 and 65 min with clonidine 4 mcg·kg−1. Clonidine doses 0.5–3 mcg·kg−1 did not affect hospital discharge time. Conclusions Clonidine administered intraoperatively for (adeno) tonsillectomy or adenoidectomy prolonged emergence from anesthesia. Doses of 0.5–3 mcg·kg−1 caused greater sedation in the postanesthesia care unit but did not impact on hospital discharge times.

The oxidation of CO to CO2 is necessary in the operation of Proton Exchange Membrane Fuel Cells (PEMFCs) since even a small amount of CO that is formed when the PEMFC is operated under ambient conditions is sufficient to poison the Pt catalyst in the electrodes and degrade the performance. Operation using higher loads of Pt catalysts or increasing the purity of the H2 input gas significantly adds to the cost, adversely impacting the commercial development of PEMFCs. We combined graphene oxide (GO) with metallic salts and partially reduced the mixture with sodium borohydride, yielding a metallized form of partially reduced graphene oxide (prGO) platelets that remained in solution. When these platelets were coated on the Nafion membrane of a PEMFC, a 72% increase in the power output was observed, whereas a 62% increase was observed when the membrane was coated with partially reduced graphene oxide without the metallic salts. Results will be presented for AuGO/prGO, PtGO/prGO, and AuPtGO/prGO combinations.

Material removal at the sub-micron level has been a topic of interest in the past few years, particularly with respect to the fabrication of miniaturized devices. While numerous techniques have been developed and refined from their larger mesoscale counterparts (e.g. microEDM, micromilling), most have inherent limitations such as tool dimensions restricting the minimum feature which can be produced. In this work, we are proposing a novel technique of using the electrokinetic phenomenon for precise material removal at rates in the order of nanometers/min. An AC electric field with a DC offset is applied to a flowing fluid containing suspended particles which will then collide with the workpiece material causing material wear and tear and thus material removal. Results showed that the technique was feasible in achieving sub-micron material removal in micro-channels up to a depth of several hundred nanometers. With no chemicals involved in the process, the technique offers the further attraction of being a benign nano-manufacturing process with potential usage in the biochip and microfluidics areas.