Toward Improving Ambient Volta Potential Measurements with SKPFM for Corrosion Studies

Scanning Kelvin probe force microscopy (SKPFM) is used in corrosion studies to quantify the relative nobility of different microstructural features present within complex metallic systems and thereby elucidate possible corrosion initiation sites. However, Volta potential differences (VPDs) measured via SKPFM in the literature for metal alloys exhibit large variability, making interpretation and application for corrosion studies difficult. We have developed an improved method for referencing SKPFM VPDs by quantifying the closely related work function of the probe relative to an inert gold standard whose modified work function is calculated via density functional theory (DFT). By measuring and tracking changes in the probe vs. gold VPD, this method compensates for some of the complex effects that cause changes in an individual probe\u27s work function. Furthermore, it provides a path toward direct, quantitative comparison of SKPFM results obtained by different researchers. Application of this method to a Cu-Ag-Ti eutectic braze of a steel sample imaged with multiple SKPFM probes of differing compositions led to enhanced repeatability both within and among probe types, as well as enabled the calculation of modified work function values for each of the microstructural constituents present

How Generation Z College Students Prefer to Learn: A Comparison of U.S. and Brazil Students

The purpose of this study was to engage in a comparative analysis of Generation Z college students in the United States and Brazil regarding characteristics, motivations, interpersonal styles, learning styles, and learning methods. Quantitative data in both countries were collected and analyzed to formulate comparative findings. Themes that emerged include learning that makes a difference, achievement orientation, logic-based learning, intrapersonal and interpersonal learning, applied and hands-on experiences, learning through words, recognition, and lacking vision, inspiration, and creativity. More similarities than differences were found across themes in both populations

Radiographic changes of the talus in congenital clubfoot after surgical release using the mckay procedure

OBJECTIVE: To analyze the morphologic changes of the talus after surgical treatment of congenital clubfoot using the McKay procedure. METHODS: We retrospectively analyzed lateral standing radiographs of the feet in 14 patients with unilateral clubfoot treated by the McKay procedure. All patients were operated on by the same surgeon, with an average of 6.53 years between surgery and the radiograph. We compared the characteristics of the talus between the operated foot and the contralateral foot. We evaluated the deformity of the domus and the head of the talus (sphericity evaluation), the talar length and height, the presence and percentage of navicular subluxation, changes in the Gissane angle, and the trabecular pattern of the bone. RESULTS: Deformities of the head of the talus were observed in 92.8% of the patients; of the domus in 92.8%; and of the trabecular pattern in 100%. The ratio between the talar lengths of the operated foot and the contralateral foot ranged from 0.61 to 0.88 (Mean 0.79, SD = 0.09), while the height ratio ranged from 0.57 to 0.98 (Mean 0.82, SD = 0.12). The Gissane angle was increased in all of the operated feet, which also showed some degree of navicular subluxation, ranging from 6.43 to 59.75% (Mean 26.34%, SD = 16.66%). CONCLUSIONS: Abnormal talar findings were observed in 100% of the feet treated using the McKay procedure. The establishment of radiographic parameters to describe and quantify these deformities was feasible through simple and easy techniques.OBJETIVO: Analisar as alterações morfológicas do tálus após o tratamento cirúrgico do pé torto congênito pela técnica de McKay. MÉTODOS: Foram analisadas, retrospectivamente, radiografias em perfil com carga dos pés de 14 pacientes com pé torto congênito unilateral submetidos ao tratamento pela técnica de McKay por dupla incisão. Todos os pacientes foram operados pelo mesmo cirurgião, com média de 6,53 anos entre a cirurgia e a radiografia. Comparamos as características do tálus dos pés operados com os parâmetros radiográficos dos pés contralaterais. Avaliamos a presença de deformidade do dômus e da cabeça do tálus (avaliação da esfericidade), a altura e o comprimento do tálus, a presença e grau de subluxação do navicular, a alteração do ângulo de Gissane e o padrão do trabeculado ósseo. RESULTADOS: Alterações da cabeça do tálus ocorreram em 92,8% dos casos; do dômus, em 92,8%; e do trabeculado, em 100%. A relação entre o comprimento do tálus do pé operado sobre o contralateral variou de 0,61 a 0,88 (média de 0,79; DP = 0,09), e da altura de 0,57 a 0,98 (média de 0,82; DP = 0,12). O ângulo de Gissane aumentou em todos os pés operados, e todos apresentaram subluxação do navicular, com índice variando de 6,43 a 59,75% (média de 26,34%; DP = 16,66%). CONCLUSÕES: Alterações talares ocorreram em 100% dos pés tratados pela técnica de McKay. Estabelecer parâmetros radiográficos para descrever e quantificar essas deformidades mostrou-se viável através de técnicas simples e de fácil execução.Universidade Federal de São Paulo (UNIFESP) Departamento de Ortopedia e Traumatologia Ortopedia PediátricaUniversidade Federal de São Paulo (UNIFESP) Departamento de Ortopedia e TraumatologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de Diagnóstico por ImagemUNIFESP, Depto. de Ortopedia e Traumatologia Ortopedia PediátricaUNIFESP, Depto. de Ortopedia e TraumatologiaUNIFESP, Depto. de Diagnóstico por ImagemSciEL

Accelerated neuritogenesis and maturation of primary spinal motor neurons in response to nanofibers

Neuritogenesis, neuronal polarity formation, and maturation of axons and dendrites are strongly influenced by both biochemical and topographical extracellular components. The aim of this study was to elucidate the effects of polylactic acid electrospun fiber topography on primary motor neuron development, because regeneration of motor axons is extremely limited in the central nervous system and could potentially benefit from the implementation of a synthetic scaffold to encourage regrowth. In this analysis, we found that both aligned and randomly oriented submicron fibers significantly accelerated the processes of neuritogenesis and polarity formation of individual cultured motor neurons compared to flat polymer films and glass controls, likely due to restricted lamellipodia formation observed on fibers. In contrast, dendritic maturation and soma spreading were inhibited on fiber substrates after 2 days in vitro . This study is the first to examine the effects of electrospun fiber topography on motor neuron neuritogenesis and polarity formation. Aligned nanofibers were shown to affect the directionality and timing of motor neuron development, providing further evidence for the effective use of electrospun scaffolds in neural regeneration applications. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 589–603, 2010Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77438/1/20792_ftp.pd

Dimethyl sulfoxide blocks herpes simplex virus-1 productive infection in vitro acting at different stages with positive cooperativity. Application of micro-array analysis

BACKGROUND: Dimethyl sulfoxide (DMSO) is frequently used at a concentration of up to 95% in the formulation of antiherpetic agents because of its properties as a skin penetration enhancer. Here, we have analyzed the effect of DMSO on several parameters of Herpes Simplex Virus replication. METHODS: Productive infection levels of HSV-1 were determined by plaque assay or by reporter gene activity, and its DNA replication was estimated by PCR. Transcript levels were evaluated with HSV-specific DNA micro-arrays. RESULTS: DMSO blocks productive infection in vitro in different cell types with a 50% inhibitory concentration (IC(50)) from 0.7 to 2% depending upon the multiplicity of infection. The concentration dependence exhibits a Hill coefficient greater than 1, indicating that DMSO blocks productive infection by acting at multiple different points (mechanisms of action) with positive cooperativity. Consistently, we identified at least three distinct temporal target mechanisms for inhibition of virus growth by DMSO. At late stages of infection, DMSO reduces virion infectivity, and markedly inhibits viral DNA replication. A third mode of action was revealed using an oligonucleotide-based DNA microarray system for HSV. These experiments showed that DMSO reduced the transcript levels of many HSV-1 genes; including several genes coding for proteins involved in forming and assembling the virion. Also, DMSO markedly inhibited some but not all early transcripts indicating a previously unknown mode for inhibiting the early phase of HSV transcription-replication cycle. CONCLUSION: These observations suggest that DMSO itself may have a role in the anti-herpetic activity of formulations utilizing it as a dispersant

Growth and nutrition in children with Ataxia telangiectasia

Background: Ataxia telangiectasia (A-T) is a rare multisystem disease with high early mortality from lung disease and cancer. Nutritional failure adversely impacts outcomes in many respiratory diseases. Several factors influence nutrition in children with A-T. We hypothesised that children with A-T have progressive growth failure and that early gastrostomy tube feeding (percutaneous endoscopic gastrostomy, or PEG) is a favourable management option with good nutritional outcomes. Methods: Data were collected prospectively on weight, height and body mass index (BMI) at the national paediatric A-T clinic. Adequacy and safety of oral intake was assessed. Nutritional advice was given at each multidisciplinary review. Results: 101 children (51 girls) had 222 measurements (32 once, 32 twice, 24 thrice) between 2009 and 2016. Median (range) age was 9.3 (1.5 to 18.4) years. Mean (sd) weight, height and BMI Z-scores were respectively -1.03(1.57), -1.17 (1.18) and -0.36 (1.43). 35/101 children had weight Z-scores below -2 on at least one occasion. Weight, height and BMI Z-scores declined over time. Decline was most obvious after 8 years of age. 14/101 (13.9%) children had a PEG, with longitudinal data available for 12. In a nested case control study, there was a trend for improvement in weight in those with a PEG (p = 0.06). Conclusions: A-T patients decline in growth over time. There is an urgent need for new strategies, including an understanding of why growth falters. We suggest early proactive consideration of PEG from age 8 years onwards in order to prevent progressive growth failure

Age-Related Attenuation of Dominant Hand Superiority

The decline of motor performance of the human hand-arm system with age is well-documented. While dominant hand performance is superior to that of the non-dominant hand in young individuals, little is known of possible age-related changes in hand dominance. We investigated age-related alterations of hand dominance in 20 to 90 year old subjects. All subjects were unambiguously right-handed according to the Edinburgh Handedness Inventory. In Experiment 1, motor performance for aiming, postural tremor, precision of arm-hand movement, speed of arm-hand movement, and wrist-finger speed tasks were tested. In Experiment 2, accelerometer-sensors were used to obtain objective records of hand use in everyday activities

Episodic Therapy for Genital Herpes in Sub-Saharan Africa: A Pooled Analysis from Three Randomized Controlled Trials

BACKGROUND: A randomized controlled trial in South Africa found a beneficial effect of acyclovir on genital ulcer healing, but no effect was seen in trials in Ghana, Central African Republic and Malawi. The aim of this paper is to assess whether the variation in impact of acyclovir on ulcer healing in these trials can be explained by differences in the characteristics of the study populations. METHODOLOGY/PRINCIPAL FINDINGS: Pooled data were analysed to estimate the impact of acyclovir on the proportion of ulcers healed seven days after randomisation by HIV/CD4 status, ulcer aetiology, size and duration before presentation; and impact on lesional HIV-1. Risk ratios (RR) were estimated using Poisson regression with robust standard errors. Of 1478 patients with genital ulcer, most (63%) had herpetic ulcers (16% first episode HSV-2 ulcers), and a further 3% chancroid, 2% syphilis, 0.7% lymphogranuloma venereum and 31% undetermined aetiology. Over half (58%) of patients were HIV-1 seropositive. The median duration of symptoms before presentation was 6 days. Patients on acyclovir were more likely to have a healed ulcer on day 7 (63% vs 57%, RR = 1.08, 95% CI 0.98-1.18), shorter time to healing (p = 0.04) and less lesional HIV-1 RNA (p = 0.03). Small ulcers (<50 mm(2)), HSV-2 ulcers, first episode HSV-2 ulcers, and ulcers in HIV-1 seropositive individuals responded best but the better effectiveness in South Africa was not explained by differences in these factors. CONCLUSIONS/SIGNIFICANCE: There may be slight benefit in adding acyclovir to syndromic management in settings where most ulcers are genital herpes. The stronger effect among HIV-1 infected individuals suggests that acyclovir may be beneficial for GUD/HIV-1 co-infected patients. The high prevalence in this population highlights that genital ulceration in patients with unknown HIV status provides a potential entry point for provider-initiated HIV testing

Cytomegalovirus Viremia as a Risk Factor for Mortality Prior to Antiretroviral Therapy among HIV-Infected Gold Miners in South Africa

BACKGROUND: Cytomegalovirus (CMV) viremia has been shown to be an independent risk factor for increased mortality among HIV-infected individuals in the developing world. While CMV infection is nearly ubiquitous in resource-poor settings, few data are available on the role of subclinical CMV reactivation on HIV. METHODS: Using a cohort of mineworkers with stored plasma samples, we investigated the association between CMV DNA concentration and mortality prior to antiretroviral therapy availability. RESULTS: Among 1341 individuals (median CD4 count 345 cells/µl, 70% WHO stage 1 or 2, median follow-up 0.9 years), 70 (5.2%) had CMV viremia at baseline; 71 deaths occurred. In univariable analysis CMV viremia at baseline was associated with a three-fold increase in mortality (hazard ratio [HR] 3.37; 95% confidence intervals [CI] 1.60, 7.10). After adjustment for CD4 count, WHO stage and HIV viral load (N = 429 with complete data), the association was attenuated (HR 2.27; 95%CI 0.88, 5.83). Mortality increased with higher CMV viremia (≥1,000 copies/ml vs. no viremia, adjusted HR 3.65, 95%CI: 1.29, 10.41). Results were similar using time-updated CMV viremia. CONCLUSIONS: High copy number, subclinical CMV viremia was an independent risk factor for mortality among male HIV-infected adults in South Africa with relatively early HIV disease. Studies to determine whether anti-CMV therapy to mitigate high copy number viremia would increase lifespan are warranted