Films of Graphene Nanomaterials Formed by Ultrasonic Spraying of Their Stable Suspensions

Graphene, a two-dimensional carbon allotrope, exhibits excellent optoelectronic properties. The assembly of graphene into films provides a platform to deepen the study of its interaction with varying surfaces, to engineer devices, and to develop functional materials. A general approach to produce graphene films consists of preparing a dispersion and laying it on a substrate of choice, followed by solvent evaporation. Here, we report the preparation of stable suspensions of new types of graphene nanomaterials namely, graphene nanoflowers (GNFs) and multi-layer graphene (MLG) flakes, in ethanol, N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP). Sprayable suspensions of both GNFs and MLG were prepared in DMF/ethanol, which showed high stability, without addition of any surfactant. The stable suspensions were used to deposit micrometer-thick MLG/GNF films on glass substrates. Calculations of initial droplet size and of timescale of droplet evaporation are performed and possible thermophoretic effects on droplet deposition discussed as well. Coating glass substrates with a methacrylic acid–methyl methacrylate (MA) copolymer prior to the deposition significantly improved the adhesion of the nanomaterials to the substrate. With the MA coating, a substrate coverage of nearly 100% was achieved at 14-min spraying time for 0.05 wt% GNF and 0.1 wt% MLG suspensions. Raman spectra of the GNF and MLG films reveal that the films were made of MLG in which the individual graphene layers rotated from each other as in turbostratic graphene. This work provides a general approach to prepare graphene nanomaterial suspensions and to create films for a variety of applications. The spraying process applied in the current work is highly scalable and allows control of film characteristics through process parameters.

Copyright 2015 American Association for Aerosol Research     

EBR-II driver fuel qualification for loss-of-flow and loss-of-heat-sink tests without scram

The continuing development of metallic fuel in EBR-II has led to performance of whole core transient tests which exceed normal driver fuel operating limits. Both out-of-reactor and in-reactor tests have been completed to investigate failure modes for metallic fuel elements. Equations have been developed to predict both time-to-failure and fuel element damage caused by thermal transients. These analyses have allowed operation of EBR-II in modes that demonstrate the inherent safety of both the plant design and the metallic fuel element design.     

Ethical dilemmas in AIDS research: Individual privacy and public health.

Research on the acquired immune deficiency syndrome (AIDS) presents a stark example of the dilemmas involved in balancing individual rights and social welfare in conducting psychosocial research. These dilemmas are pronounced in research on public health. Unfortunately, significant legal threats to confidentiality are matched inadequately by legal means of protecting privacy. Researchers are advised to request certificates of confidentiality from the Public Health Service. A privilege statute is needed to protect the privacy of participants in research on AIDS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Safety analysis for the loss-of-flow and loss-of-heat sink without scram tests in EBR-II

This paper discusses the safety considerations and the analysis that was done to support the conduct of the Loss-of-Flow and Loss-of-Heat Sink Without Scram tests in EBR-II. The plant safety limits and the analysis codes and methods are presented. The impact of the tests and off-normal conditions on the fuel and plant structures is evaluated. Conclusions are that the test program had no impact on plant operations and the accumulated fuel damage was negligible.     

Effects of headings on text processing.

Reports 2 experiments concerned with the effects of headings, both embedded and intact (outline), on the processing of complex text material. Results of Exp I with 132 undergraduates indicate that embedded headings reliably improved delayed test performance. In Exp II with 106 Ss, it was further found that instructions in the use of headings as processing aids facilitated test performance. A discrepancy, however, was observed between the 2 experiments in that the presentation of headings without instructions failed to increase test scores significantly on the dependent measures of Exp II. Sensitization to the headings is proposed as one possible explanation for the results. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of behavioral and pharmacological treatment on smokeless tobacco users.

The purpose of this study was to examine the effects of 2 mg of nicotine polacrilex versus placebo gum and of group behavioral treatment versus minimal contact on cessation of smokeless tobacco use. Participants (N?=?210) were randomly assigned 1 of the 4 treatment conditions. Withdrawal symptoms were assessed throughout the treatment. Follow-up assessments were made at 1, 6, and 12 months posttreatment. Survival curve analysis showed that any of the 3 treatment groups involving group behavioral therapy or placebo gum were equally effective and superior to the minimal contact plus 2 mg of nicotine gum treatment in terms of abstinence. On the other hand, withdrawal symptoms were significantly reduced by nicotine gum, compared with placebo during the initial phases of cessation. The ineffectiveness of nicotine gum on treatment outcome may be attributed to its similarity with smokeless tobacco. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association of a polymorphism in the beta 3-adrenergic-receptor gene with features of the insulin resistance syndrome in Finns

BACKGROUND: Because visceral obesity predicts insulin resistance, we studied whether alterations in the gene encoding for the beta 3-adrenergic receptor in visceral fat are associated with insulin resistance. METHODS: We studied the frequency of a cytosine-to-thymidine mutation that results in the replacement of tryptophan by arginine at position 64 (Trp64Arg) of the beta 3-adrenergic receptor by restriction-enzyme digestion with BstOl in 335 subjects from western Finland, 207 of whom were nondiabetic and 128 of whom had non-insulin-dependent diabetes mellitus (NIDDM). We also determined the frequency of the mutation in 156 subjects from southern Finland. Sensitivity to insulin was measured by the hyperinsulinemic-euglycemic clamp technique in 66 randomly selected nondiabetic subjects. RESULTS: In the subjects from western Finland, the frequency of the mutated allele was similar in the nondiabetic subjects and the subjects with NIDDM (12 vs. 11 percent). The mean age of the subjects at the onset of diabetes was lower among those with the mutation than those without it (56 vs. 61 years, P = 0.04). Among the nondiabetic subjects, those with the mutation had a higher ratio of waist to hip circumference (P = 0.02), a greater increase in the serum insulin response after the oral administration of glucose (P = 0.05), a higher diastolic blood pressure (82 vs. 78 mm Hg, P = 0.01), and a lower rate of glucose disposal during the clamp study (5.3 vs. 6.5 mg [29 vs. 36 mumol] per kilogram of body weight per minute; P = 0.04) than the subjects without the mutated allele. In an analysis of sibling pairs, the siblings with the mutation generally had higher waist:hip ratios (P = 0.05) and higher responses of blood glucose and serum insulin after the oral administration of glucose than their siblings without the mutation (P = 0.02 and P = 0.005, respectively). CONCLUSIONS: The Trp64Arg allele of the beta 3-adrenergic receptor is associated with abdominal obesity and resistance to insulin and may contribute to the early onset of NIDDM:     

Prevention of nonadherence to nonsteroidal anti-inflammatory medications for newly diagnosed patients with juvenile rheumatoid arthritis.

Adherence to medications for chronic pediatric diseases decreases over time. This randomized controlled trial evaluated a clinic-based, nurse-administered educational and behavioral intervention to prevent the anticipated drop in adherence to nonsteroidal medications among newly diagnosed patients with juvenile rheumatoid arthritis. Thirty-four participants completed the study (mean age = 8.44 years, SD = 3.96), including 19 in the experimental group and 15 in the standard-treatment (education) control group. There were significant group and Group X Time effects for adherence (assessed with an electronic monitor over a 13-month period) favoring the experimental group. In contrast, the groups did not differ significantly in disease activity or functional limitations. Factors that may have prevented detection of differences in these health parameters are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Outbreak of Escherichia coli O157:H7 infections associated with nonintact blade-tenderized frozen steaks sold by door-to-door vendors

Steaks have not been recognized as an important vehicle of Escherichia coli O157:H7 infection. During 11 to 27 June 2003, the Minnesota Department of Health (MDH) identified four O157 infection cases with the same pulsed-field gel electrophoresis (PFGE) subtype. All four case patients consumed brand A vacuum packed frozen steaks sold by door-to-door vendors. The steaks were blade tenderized and injected with marinade (i.e., nonintact). Information from single case patients in Michigan and Kansas identified through PulseNet confirmed the outbreak. The MDH issued a press release on 27 June to warn consumers, prompting a nationwide recall of 739,000 lb (335,506 kg) of frozen beef products. The outbreak resulted in six culture-confirmed cases (including one with hemolytic uremic syndrome) and two probable cases in Minnesota and single confirmed cases in four other states. The outbreak PFGE subtype of O157 was isolated from unopened brand A bacon-wrapped fillets from five affected Minnesota households. A fillet from one affected household was partially cooked in the laboratory, and the same O157 subtype was isolated from the uncooked interior. The tenderizing and injection processes likely transferred O157 from the surface to the interior of the steaks. These processing methods create new challenges for prevention of O157 infection. Food regulatory officials should reevaluate safety issues presented by nonintact steak products, such as microbiologic hazards of processing methods, possible labeling to distinguish intact from nonintact steaks, and education of the public and commercial food establishments on the increased risk associated with undercooked nonintact steaks. Information on single cases of O157 infection in individual states identified through PulseNet can be critical in solving multistate outbreaks in a timely manner.     

Magnitude and phase in thermal wave imaging

In thermal wave imaging on solids both magnitude and phase angle are used. However, a comparison between theoretical and experimental results is lacking even for the simple case of an air-backed metal plate. In the letter we present measurements and point out the difference between sinusoidal and square-wave intensity modulation.