Role of ripples in altering the electronic and chemical properties of graphene.

Ripples of graphene are known to manipulate electronic and hydrogenation properties of graphitic materials. More detailed work is needed to elucidate the structure-property relationship of these systems. In this work, the density functional theory is used to compute the energy and electronic structure of the graphene models with respect to variable curvatures and hydrogen adsorption sites. The magnitude of finite bandgap opening depends on the orientation of ripples, and the hydrogen adsorption energy depends on the local curvature of graphene. An adsorbed hydrogen alters the local curvature, resulting in relatively weakened adsorption on the neighboring three sites, which gives a rationale to experimentally observed dynamic equilibrium stoichiometry (H:C = 1:4) of hydrogenated graphene. The surface diffusion transition state energy of adsorbed hydrogen is computed, which suggests that the Eley-Rideal surface recombination mechanism may be important to establish the dynamic equilibrium, instead of the commonly assumed Langmuir-Hinshelwood mechanism.

Outcomes of Postchemotherapy Retroperitoneal Lymph Node Dissection from a High-volume UK Centre Compared with a National Data Set.

BACKGROUND: Retroperitoneal lymph node dissection (RPLND) is essential for the treatment of metastatic germ cell tumours of the testis. Recommendations on the referral and management of complex urological cancers in the UK includes centralisation of services to regional centres. OBJECTIVE: To review contemporary PC-RPLND outcomes at a high-volume centre with a complex case-mix, and compare with national registry data. DESIGN SETTING AND PARTICIPANTS: We retrospectively reviewed the medical records of PC-RPLNDs performed for germ cell tumours at our centre between July 2012 and September 2018. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Primary outcomes were Clavien 3+ complications, histology, rates of positive margin, relapse, in-field recurrences, and mortality. Secondary outcomes were blood loss, operation time, blood transfusion, adjuvant procedures, length of stay, and lymph node count. Surgical and histological outcomes of all RPLNDs for testicular cancers were compared with national RPLND registry data. For statistical difference, χ2 testing was used. RESULTS AND LIMITATIONS: A total of 178 procedures were performed, including 31 (17%) redo RPLNDs. Clavien 3+ complications occurred in 11 (7%). Histological findings in non-redo cases were the following: necrosis 24%, teratoma 62%, viable germ cell tumour 11%, and dedifferentiated cancers 3%. Rates of positive margin, relapse, and in-field recurrence were 11%, 17%, and 2%, respectively. Overall survival was 89% at a median of 36 mo. The median blood loss was 650 ml (350, 1250), with a transfusion rate of 8%. Nephrectomy, vascular reconstruction, and visceral resection was required in 12%, 6%, and 3% respectively. The median inpatient stay was 6 d (5, 8) and the median node count was 35 (20, 37). A comparison of all RPLNDs with national data showed no statistical difference in primary outcomes. Our blood transfusion rate was significantly lower (12% vs 21%, χ2 [1, N = 322] = 4.296, p = 0.038). CONCLUSIONS: Centralisation led to high quality of RPLND in UK. Within that, our series (the largest in the UK) demonstrates no significant difference in outcomes despite higher complexity cases. Our blood transfusion rates are in fact lower than national figures. Complex RPLNDs should be performed in high-volume centres where possible. PATIENT SUMMARY: In the UK, retroperitoneal lymph node dissections (RPLND) are centralised to specialist centres and the quality of surgery is high, with low complications and good histological outcomes. When compared to national data, we found no significant difference in the majority of outcomes from our high-volume centre despite our complex case-mix.

Antidelaminating, Thermally Stable, and Cost-Effective Flexible Kapton Platforms for Nitrate Sensors, Mercury Aptasensors, Protein Sensors, and p-Type Organic Thin-Film Transistors.

The inkjet printing of metal electrodes on polymer films is a desirable manufacturing process due to its simplicity but is limited by the lack of thermal stability and serious delaminating flaws in various aqueous and organic solutions. Kapton, adopted worldwide due to its superior thermal durability, allows the high-temperature sintering of nanoparticle-based metal inks. By carefully selecting inks (Ag and Au) and Kapton substrates (Kapton HN films with a thickness of 135 µm and a thermal resistance of up to 400 °C) with optimal printing parameters and simplified post-treatments (sintering), outstanding film integrity, thermal stability, and antidelaminating features were obtained in both aqueous and organic solutions without any pretreatment strategy (surface modification). These films were applied in four novel devices: a solid-state ion-selective (IS) nitrate (NO3-) sensor, a single-stranded DNA (ssDNA)-based mercury (Hg2+) aptasensor, a low-cost protein printed circuit board (PCB) sensor, and a long-lasting organic thin-film transistor (OTFT). The IS NO3- sensor displayed a linear sensitivity range between 10-4.5 and 10-1 M (r2 = 0.9912), with a limit of detection of 2 ppm for NO3-. The Hg2+ sensor exhibited a linear correlation (r2 = 0.8806) between the change in the transfer resistance (RCT) and the increasing concentration of Hg2+. The protein PCB sensor provided a label-free method for protein detection. Finally, the OTFT demonstrated stable performance, with mobility values in the linear (µlin) and saturation (µsat) regimes of 0.0083 ± 0.0026 and 0.0237 ± 0.0079 cm2 V-1 S-1, respectively, and a threshold voltage (Vth) of -6.75 ± 3.89 V.

Multi-Scale Analyses and Modeling of Metallic Nano-Layers.

The current work centers on multi-scale approaches to simulate and predict metallic nano-layers' thermomechanical responses in crystal plasticity large deformation finite element platforms. The study is divided into two major scales: nano- and homogenized levels where Cu/Nb nano-layers are designated as case studies. At the nano-scale, a size-dependent constitutive model based on entropic kinetics is developed. A deep-learning adaptive boosting technique named single layer calibration is established to acquire associated constitutive parameters through a single process applicable to a broad range of setups entirely different from those of the calibration. The model is validated through experimental data with solid agreement followed by the behavioral predictions of multiple cases regarding size, loading pattern, layer type, and geometrical combination effects for which the performances are discussed. At the homogenized scale, founded on statistical analyses of microcanonical ensembles, a homogenized crystal plasticity-based constitutive model is developed with the aim of expediting while retaining the accuracy of computational processes. Accordingly, effective constitutive functionals are realized where the associated constants are obtained via metaheuristic genetic algorithms. The model is favorably verified with nano-scale data while accelerating the computational processes by several orders of magnitude. Ultimately, a temperature-dependent homogenized constitutive model is developed where the effective constitutive functionals along with the associated constants are determined. The model is validated by experimental data with which multiple demonstrations of temperature effects are assessed and analyzed.

Effect of ionizing radiation and chewing simulation on human enamel and zirconia.

PURPOSE: To evaluate the effect of ionizing irradiation on human enamel and zirconia after chewing simulation. METHODS: Twenty enamel and twenty translucent Yttria-stabilized zirconia (Y-PSZ) specimens were divided in 4 groups: Co (control) - no irradiation on enamel cusps/opposing zirconia slabs; E70 - irradiated (70 Gray) enamel cusps/opposing irradiated enamel slabs; Z70 - irradiated zirconia cusps/opposing irradiated zirconia slabs; EZ70 - irradiated enamel cusps/opposing irradiated zirconia slabs. Cusps were abraded against slabs in a chewing simulator (CS - one million cycles, 80 N, artificial saliva, 37˚C). Wear and roughness of zirconia and enamel were analyzed using a stylus profilometer. The abraded enamel was analyzed by Electron probe micro-analyzer (EPMA) and zirconia was characterized by nanoindentation and X-ray diffraction. One-way analysis of variance (ANOVA) and Tukey test were used for analysis of wear, Repeated Measures and Bonferroni test for roughness, and hardness and modulus values were compared using Wilcoxan Mann Whitney rank sum test (overall 5% significance). RESULTS: Significantly higher volume loss was presented by cusps in the E70 group (p<0.001). Wear was similar between Co and EZ70 groups. There was no significant effect of irradiation on roughness of enamel or zirconia slabs (p=0.072). Irradiated Y-PSZ slabs had significantly higher hardness and modulus than non-irradiated ones and a 7% increase in m phase content was detected after irradiation. CONCLUSIONS: The opposing surface characteristics played a more significant role on enamel wear than did ionizing radiation. However, radiation affects Y-PSZ crystalline composition, hardness and modulus of elasticity.

Well-Adhered Copper Nanocubes on Electrospun Polymeric Fibers.

Electrospun polymer fibers can be used as templates for the stabilization of metallic nanostructures, but metallic species and polymer macromolecules generally exhibit weak interfacial adhesion. We have investigated the adhesion of model copper nanocubes on chemically treated aligned electrospun polyacrylonitrile (PAN) fibers based on the introduction of interfacial shear strains through mechanical deformation. The composite structures were subjected to distinct macroscopic tensile strain levels of 7%, 11%, and 14%. The fibers exhibited peculiar deformation behaviors that underscored their disparate strain transfer mechanisms depending on fiber size; nanofibers exhibited multiple necking phenomena, while microfiber deformation proceeded through localized dilatation that resulted in craze (and microcrack) formation. The copper nanocubes exhibited strong adhesion on both fibrous structures at all strain levels tested. Raman spectroscopy suggests chemisorption as the main adhesion mechanism. The interfacial adhesion energy of Cu on these treated PAN nanofibers was estimated using the Gibbs-Wulff-Kaischew shape theory giving a first order approximation of about 1 J/m2. A lower bound for the system's adhesion strength, based on limited measurements of interfacial separation between PAN and Cu using mechanically applied strain, is 0.48 J/m2.

Nisin infusion into surface cracks in oxide coatings to create an antibacterial metallic surface.

The efficacy of surface topology and chemistry on the ability for a surface to retain antimicrobial performance via the immobilization of a peptide was evaluated. A nanosecond pulsed laser was used to create oxide films on Ti-6Al-4V and 304L stainless steel. The laser conditions employed created a mudflat cracked surface on titanium, but no cracks on the steel. An antimicrobial peptide, nisin, was infused into the cracked and uncracked oxide surfaces to provide antimicrobial activity against Gram-positive bacteria; Listeria monocytogenes was chosen as the model microorganism. Release tests in distilled water at room temperature show that nisin is slowly liberated from the uncracked stainless steel surface, while there was no evidence of nisin liberation from the cracked titanium alloy surfaces, likely due to immobilization of the peptide into the artificially created micro-cracks on the surface of this alloy. Surfaces treated with nisin became active and exhibit anti-microbial performance against L. monocytogenes; this behavior is mostly retained after scrubbing/washing and simple immersion in water.

Uncovering the Thermo-Kinetic Origins of Phase Ordering in Mixed-Valence Antimony Tetroxide by First-Principles Modeling.

Phase ordering in the mixed-valence oxide Sb2O4 has been examined by density functional theory (DFT) calculations. We find that the ground-state total energies of the two phases (α and ß) are almost degenerate and are highly sensitive to the choice of the approximation to the exchange correlation (xc) functional used in our calculations. Interestingly, with the inclusion of the zero-point energy corrections, the α phase is predicted to be the ground state polymorph for most xc functionals used. We also illustrate the pronounced stereochemical activity of Sb in these polymorphs of Sb2O4, setting an exception to the Keve and Skapski rule. Here, we find that the actual bonding in the α phase is more asymmetric, while the anomalous stability of the ß phase could be rationalized from kinetic considerations. We find a non-negligible activation barrier for this α-ß phase transition, and the presence of a saddle point (ß phase) supports the separation of Sb(III) over a continuous phase transition, as observed in experiments.

Effect of accelerated aging on dental zirconia-based materials.

OBJECTIVE: To investigate the effect of aging on phase transformation and mechanical properties of yttria-tetragonal zirconia polycrystal (Y-TZP). MATERIALS AND METHODS: Fully-sintered Y-TZP slabs, IPS E-max ZirCAD (ZC - Ivoclar) and Z-5 ceramic (Z5 - C5 Medical Werks), were artificially aged in autoclave for: 0, 30, 60 or 90min. Flexural strength (FS), crystalline changes (X-ray diffraction analysis - XRD) and surface topography were analyzed. 0 and 90min-aged samples were evaluated by nanoindentation to measure hardness and modulus, and results were compared using Wilcoxan Mann Whitney rank sum test (p≤0.05). FS results were compared using two-way ANOVA and Tukey HSD (α=0.05). RESULTS: Material factor had significant effect (p=0.001) on flexural strength (Z5=966.95MPa; ZC=847.82MPa), but aging did not. Nanoindentation showed incidence of typical load/depth curves combined with some exhibiting features compatible with cracking. When typical curves were considered, aging had no effect on the modulus and hardness, but hardness was dependent on material type. A steady increase in the m phase related to aging time was observed for ZC samples. The maximum incidence of m phase was 6.56% for Z5/60min. SIGNIFICANCE: Flexural strength is not affected by surface transformation in dental Y-TZP. Hydrothermal aging has an effect on m content and surface topography of different zirconia brands, but mechanical tests that can precisely characterize surface changes in aged Y-TZP are still missing.

A 6-year Follow-up survey of health status in middle-aged women with Turner syndrome.

OBJECTIVE: Studies suggest younger women with Turner syndrome (TS) have good quality of life. Less is known about everyday functioning in adults with TS. In a 6-year follow-up study, multiple areas of functioning were compared between TS women and controls. DESIGN: Women with TS and controls were mailed a self-report survey 6 years after a baseline study. PATIENTS: Fifty-seven women with TS (M age 40·6 ± 11·1 years) and 101 controls (M age 38·8 ± 10·6 years, ns) responded. MEASUREMENTS: Measures of background information, experienced life strain and presence/impact of health conditions were developed for this study. The QPS Nordic measured perceived workload challenges. The LiSat-9 measured life satisfaction. The Rosenberg Self-Esteem Scale measured self-esteem. RESULTS: More TS women lived alone, fewer had biological children, and more had adoptive children. TS women reported fewer sex partners and less sexual confidence. Controls had higher education. There was no difference in employment status. More TS women received disability pensions. TS women reported their work as more physically challenging, less positively challenging and requiring less knowledge skills. TS women experienced more life strain in school, adolescence and late working life. Controls reported higher overall life satisfaction, with no difference between samples on specific domains. TS women reported lower self-esteem. For TS women only, physical health at baseline predicted length of education and mental health at baseline predicted self-esteem. CONCLUSIONS: Women with TS face more challenges than controls on several domains of functioning. Early physical and mental health may influence later educational achievement and self-esteem for women with TS.

Improved electro-mechanical performance of gold films on polyimide without adhesion layers.

Thin metal films on polymer substrates are of interest for flexible electronic applications and often utilize a thin interlayer to improve adhesion of metal films on flexible substrates. This work investigates the effect of a 10 nm Cr interlayer on the electro-mechanical properties of 50 nm Au films on polyimide substrates. Ex situ and in situ fragmentation experiments reveal the Cr interlayer causes brittle electro-mechanical behaviour, and thin Au films without an interlayer can support strains up to 15% without significantly degrading electrical conductivity.

Nanomechanical testing technique for millimeter-sized and smaller molecular crystals.

Large crystals are used as a control for the development of a mounting and nanoindentation testing technique for millimeter-sized and smaller molecular crystals. Indentation techniques causing either only elastic or elastic-plastic deformation produce similar results in assessing elastic modulus, however, the elastic indents are susceptible to surface angle and roughness effects necessitating larger sample sizes for similar confidence bounds. Elastic-plastic indentations give the most accurate results and could be used to determine the different elastic constants for anisotropic materials by indenting different crystal faces, but not by rotating the indenter about its axis and indenting the same face in a different location. The hardness of small and large crystals is similar, suggesting that defect content probed in this study is similar, and that small crystals can be compared directly to larger ones. The Young's modulus and hardness of the model test material, griseofulvin, are given for the first time to be 11.5GPa and 0.4GPa respectively.

Mutation detection in formalin-fixed prostate cancer biopsies taken at the time of diagnosis using next-generation DNA sequencing.

AIMS: Assessing whether next-generation DNA sequencing (NGS) can be used to screen prostate cancer for multiple gene alterations in men routinely diagnosed with this disease and/or who are entered into clinical trials. Previous studies are limited and have reported only low success rates. METHODS: We marked areas of cancer on H&E-stained sections from formalin-fixed needle biopsies, and used these as templates to dissect cancer-rich tissue from adjacent unstained sections. DNA was prepared using a Qiagen protocol modified to maximise DNA yield. The DNA was screened simultaneously for mutations in 365 cancer-related genes using an Illumina HiSeq 2000 NGS platform. RESULTS: From 63 prostate cancers examined, 59(94%) of the samples yielded at least 30 ng of DNA, the minimum amount of DNA considered suitable for NGS analysis. Patients in the D'Amico high-risk group yielded an average of 1033 ng, intermediate-risk patients 401 ng, and low-risk patients 97 ng. NGS of eight samples selected from high-risk and intermediate-risk groups gave a median exon read depth of 962 and detected TMPRRS2-ERG fusions, as well as a variety of mutations including those in the SPOP, TP53, ATM, MEN1, NBPF10, NCOR2, PIK3CB and MAP2K5 (MEK5) genes. CONCLUSIONS: Using the methods presented here, NGS technologies can be used to screen a high proportion of patients with prostate cancer for mutations in cancer-related genes in tissue samples opening up its general use in the context of clinical trials or routine diagnosis.

"She came out of mum's tummy the wrong way". (Mis)conceptions among siblings of children with rare disorders.

Misconceptions or uncertainty about the rare disorder of a sibling may cause adjustment problems among children. New knowledge about their misconceptions may enable genetic counselors to provide targeted information and increase siblings' knowledge. This study aims to describe misconceptions and uncertainties of siblings of children with rare disorders. Content analysis was applied to videotapes of 11 support group sessions with 56 children aged 6 to 17. First, children's statements about the disorder (turns) were categorized into the categories "identity," "cause," "cure," "timeline," and "consequences" and then coded as medically "correct," "misunderstood," or "uncertain." Next, turns categorized as "misunderstood" or "uncertain" were analyzed to explore prominent trends. Associations between sibling age, type of disorder, and frequency of misconceptions or uncertainties were analyzed statistically. Approximately 16 % of the children's turns were found to involve misconceptions or uncertainty about the disorder, most commonly about the identity or cause of the disorder. Misconceptions seemed to originate from information available in everyday family life, generalization of lay beliefs, or through difficulties understanding abstract medical concepts. Children expressed uncertainty about the reasons for everyday experiences (e.g. the abnormal behavior they observed). A lack of available information was described as causing uncertainty. Misconceptions and uncertainties were unrelated to child age or type of disorder. The information needs of siblings should always be addressed during genetic counseling, and advice and support offered to parents when needed. Information provided to siblings should be based on an exploration of their daily experiences and thoughts about the rare disorder.

A review of volume-area scaling of glaciers.

Volume-area power law scaling, one of a set of analytical scaling techniques based on principals of dimensional analysis, has become an increasingly important and widely used method for estimating the future response of the world's glaciers and ice caps to environmental change. Over 60 papers since 1988 have been published in the glaciological and environmental change literature containing applications of volume-area scaling, mostly for the purpose of estimating total global glacier and ice cap volume and modeling future contributions to sea level rise from glaciers and ice caps. The application of the theory is not entirely straightforward, however, and many of the recently published results contain analyses that are in conflict with the theory as originally described by Bahr et al. (1997). In this review we describe the general theory of scaling for glaciers in full three-dimensional detail without simplifications, including an improved derivation of both the volume-area scaling exponent γ and a new derivation of the multiplicative scaling parameter c. We discuss some common misconceptions of the theory, presenting examples of both appropriate and inappropriate applications. We also discuss potential future developments in power law scaling beyond its present uses, the relationship between power law scaling and other modeling approaches, and some of the advantages and limitations of scaling techniques.

Health status in women with Turner syndrome: a questionnaire study on health status, education, work participation and aspects of sexual functioning.

CONTEXT: Turner syndrome (TS) is a complex medical condition with specific cognitive and psychosocial characteristics and frequent medical morbidity. Few studies have investigated the influence this has on health status, education and ability to work. OBJECTIVE: To explore health status, level of education, work participation, medical conditions, physical activity, satisfaction with life and aspects of sexual functioning in adult TS women and compare with a matched control group. DESIGN: A questionnaire was sent to 168 adult women with TS >18 years registered in a database of Frambu Resource Centre for Rare Disorders and The TS Association in Norway. We assessed health status with Short Form 36, education with Norwegian Standard Classification of Education, and employment with The General Nordic Questionnaire. Life satisfaction was measured with LiSat-9, and questions on psychological strain during life phases were included. RESULTS: Eighty women with TS (34.0 +/- 11.7 years) and 214 controls (32.9 +/- 10.6) responded. The TS group reported significantly more health problems and impaired health status in the two subscales "physical functioning" and "general health" (P < 0.001). Level of education and work participation was similar among TS and controls. TS moved away from their parents' home later than controls (20.4 +/- 4.0 vs. 18.7 +/- 2.1, P = 0.001). Age at sexual debut differed significantly (21.2 +/- 4.3 vs. 17.3 +/- 2.4 years, P < 0.001). CONCLUSION: TS attains the same level of education and level of employment as controls, they report more frequent occurrence of medical conditions, but scored lower on only two subscales in the SF-36. Despite considerable medical morbidity, TS seem to cope well with life.

Exploiting social networks to mitigate the obesity epidemic.

Despite significant efforts, obesity continues to be a major public health problem, and there are surprisingly few effective strategies for its prevention and treatment. We now realize that healthy diet and activity patterns are difficult to maintain in the current physical environment. Recently, it was suggested that the social environment also contributes to obesity. Therefore, using network-based interaction models, we simulate how obesity spreads along social networks and predict the effectiveness of large-scale weight management interventions. For a wide variety of conditions and networks, we show that individuals with similar BMIs will cluster together into groups, and if left unchecked, current social forces will drive these groups toward increasing obesity. Our simulations show that many traditional weight management interventions fail because they target overweight and obese individuals without consideration of their surrounding cluster and wider social network. The popular strategy for dieting with friends is shown to be an ineffective long-term weight loss strategy, whereas dieting with friends of friends can be somewhat more effective by forcing a shift in cluster boundaries. Fortunately, our simulations also show that interventions targeting well-connected and/or normal weight individuals at the edges of a cluster may quickly halt the spread of obesity. Furthermore, by changing social forces and altering the behavior of a small but random assortment of both obese and normal weight individuals, highly effective network-driven strategies can reverse current trends and return large segments of the population to a healthier weight.

Characterization of flexible ECoG electrode arrays for chronic recording in awake rats.

We developed a 64-channel flexible polyimide ECoG electrode array and characterized its performance for long-term implantation, chronic cortical recording and high resolution mapping of surface-evoked potentials in awake rats. To achieve the longest possible recording periods, the flexibility of the electrode array, adhesion between the metals and carrier substrate, and biocompatibility were critical for maintaining the signal integrity. Experimental testing of thin film adhesion was applied to a gold-polyimide system in order to characterize relative interfacial fracture energies for several different adhesion layers, yielding an increase in overall device reliability. We tested several different adhesion techniques including the following: gold alone without an adhesion layer, titanium-tungsten, tantalum and chromium. We found titanium-tungsten to be a suitable adhesion layer considering the biocompatibility requirements as well as stability and delamination resistance. While chromium and tantalum produced stronger gold adhesion, concerns over biocompatibility of these materials require further testing. We implanted the polyimide ECoG electrode arrays through a slit made in the skull of rats and recorded cortical surface evoked responses. The arrays performed reliably over a period of at least 100 days and signals compared well with traditional screw electrodes, with better high frequency response characteristics. Since the ultimate goal of chronically implanted electrode arrays is for neural prosthetic devices that need to last many decades, other adhesion layers that would prove safe for implantation may be tested in the same way in order to improve the device reliability.