STM-induced surface aggregates on metals and oxidized silicon

We have observed an aggregation of carbon or carbon derivatives on platinum and natively oxidized silicon surfaces during STM measurements in ultra-high vacuum on solvent-cleaned samples previously structured by e-beam lithography. We have imaged the aggregated layer with scanning tunneling microscopy (STM) as well as scanning electron microscopy (SEM). The amount of the aggregated material increases with the number of STM scans and with the tunneling voltage. Film thicknesses of up to 10 nm with five successive STM measurements have been obtained

Reel Black Masculinities: Using Film and Media Literacy to Provide Opportunities for White Female Future Teachers to See Black Males Through a Culturally Responsive Lens

The purpose of this study was to document how popular film was used to provide opportunities for future teachers to explore their perceptions of Black masculinities and the lived experiences of young Black men. A case study design was used and data was gathered through a perceptions survey, interviews, observations, a focus group, and analysis of written reflections and computer-mediated communication (Merriam, 1998). Purposeful sampling was used to select two instructors from a large, public university in the North East and they were observed and interviewed. Boyz N the Hood and Finding Forrester were used in a diversity course, secondary English methods course and an adolescent literature course. A third instructor from a private university in the North East was interviewed regarding Stand and Deliver in a course on culturally relevant math strategies. Fifty-eight future teachers also participated in the study. The majority of participants were White females and therefore representative of the current teacher workforce (Swartz, 2003; National Center for Educational Statistics, 2003). The interpretational analysis of the data used a culturally responsive lens (Gay & Kirkland, 2003; Kea, Campbell-Whatley & Richards 2004) and a media literacy framework (Kellner & Share, 2005). Analysis of the data from the three instructors indicated that each instructor used film in different ways. Film was used (1) to inspire and encourage new teachers to teach by providing a model of a successfully implemented, culturally relevant, math lesson, (2) primarily as literature providing an opportunity for critical analysis of a non-print text and a discussion of Black male masculinities and (3) to educate students about stereotypes and their perceptions of young Black men. The data from the students indicated that (1) future teachers felt safe from criticism when they were allowed to reflect online; (2) without guidance from the instructor or critical literacy questions students were able to avoid discussions of race; (3) film provided a multi-layered image that impacted the students and; (4) cultural critical consciousness was difficult to assess and measure. Finally, a framework for using film emerged from exploring the teaching strategies used in this study

Making COVID-19-Related Decisions: A Qualitative Study of University Students

Background: SARS-Cov-2 (Coronavirus Disease or COVID-19) has impacted society greatly since its arrival to the United States. More specifically, college students have had to modify their behaviors on campus to minimize the spread of the virus.Purpose: The purpose of this study was to identify benefits and barriers to testing, reporting, and quarantining of undergraduate college students attending a large southeastern university.Methods: Undergraduate students were asked to complete an open-ended Qualtrics survey to share their perceived benefits and barriers to engage in behaviors to detect and prevent the spread of COVID-19. Data was analyzed via Grounded Theory techniques to determine codes and subsequent themes related to the probes.Results: Themes emerged in the categories of (a) Influencing Factors, and (b) Outcomes of the Health Behavior with 12 in the former and six in the latter. Emphasis on disclosure of COVID-19 status could be beneficial in preventing the spread of the virus on large college and university campuses.Conclusion: The data collected in this study can be used to inform COVID-19-related policies and health communication campaigns at similar colleges and universities

Cardioprotective Effects of Selective Mitochondrial-Targeted Antioxidants in Myocardial Ischemia/Reperfusion (I/R) Injury

During myocardial ischemia, coronary blood flow interruption deprives cardiomyocytes of oxygen, glucose and fatty acids. Ischemic damage is exacerbated by a burst of reactive oxygen species (ROS) generated at reperfusion when oxygen interacts with damaged mitochondrial electron transport chains (ETC), especially uncoupled complexes I and III (Fig. 1,2). Nicotinamide adenine dinucleotide phosphate oxidase (Nox) activity can also release ROS, inducing additional tissue/organ damage. Surgical intervention or thrombolytic treatments can restore coronary blood flow. However, as blood flow reestablishes, oxidative stress leads to I/R injury. Clinical treatment remains a challenge as no pharmaceutical agents effectively limit I/R-induced damage. Mitochondria are implicated in I/R as a major source of ROS3,4,5. Excess ROS leads to mitochondrial and cardiac contractile dysfunction6. Conventional antioxidants have limited efficacy in myocardial I/R because they are not targeted selectively to where most I/R damage occurs, in mitochondria (Fig. 3)3,4,5. Mitoquinone (mitoQ, MW=600 g/mol), a coenzyme Q analog, easily crosses phospholipid bilayers and is driven by the large electrochemical membrane potential to concentrate mitoQ several hundred-fold within mitochondria. The respiratory chain reduces mitoQ to its active ubiquinol antioxidant form to limit myocardial I/R injury5. The SS-31 (Szeto-Schiller) peptide ((D-Arg)-Dmt-Lys-Phe-Amide, MW=640 g/mol, Genemed Synthesis, Inc., San Antonio, TX) is also of interest since it is cellpermeable, specifically targeted to inner mitochondrial membranes based on its alternating cationic aromatic residue sequence, with an antioxidant dimethyltyrosine moeity. SS peptides scavenge ROS in I/R models. Although mitochondrial-targeted antioxidant pretreatment can effectively limit I/R injury, pretreatment is not always possible in cases of myocardial infarction. Therefore, evaluating cardioprotective efficacy of mitochondrialtargeted antioxidants when given at reperfusion is of high significanc

Effect of preoperative sonographic mapping on vascular access outcomes in hemodialysis patients

Effect of preoperative sonographic mapping on vascular access outcomes in hemodialysis patients.BackgroundCurrent DOQI guidelines encourage placing arteriovenous (AV) fistulas in more hemodialysis patients. However, many new fistulas fail to mature sufficiently to be useable for hemodialysis. Preoperative vascular mapping to identify suitable vessels may improve vascular access outcomes. The present study prospectively evaluated the effect of routine preoperative vascular mapping on the type of vascular accesses placed and their outcomes.MethodsDuring a 17-month period, preoperative sonographic evaluation of the upper extremity arteries and veins was obtained routinely. The surgeons used the information obtained to plan the vascular access procedure. The types of access placed, their initial adequacy for dialysis, and their long-term outcomes were compared to institutional historical controls placed on the basis of physical examination alone.ResultsThe proportion of fistulas placed increased from 34% during the historical control period to 64% with preoperative vascular mapping (P < 0.001). When all fistulas were assessed, the initial adequacy rate for dialysis increased mildly from 46 to 54% (P = 0.34). For the subset of forearm fistulas, the initial adequacy increased substantially from 34 to 54% (P = 0.06); the greatest improvement occurred among women (from 7 to 36%, P = 0.06) and diabetic patients (from 21 to 50%, P = 0.055). In contrast, the initial adequacy rate of upper arm fistulas was not improved by preoperative vascular mapping (59 vs. 56%, P = 0.75). Primary access failure was higher for fistulas than grafts (46.4 vs. 20.6%, P = 0.001), but the subsequent long-term failure rate was higher for grafts than fistulas (P < 0.05). Moreover, grafts required a threefold higher intervention rate (1.67 vs. 0.57 per year, P < 0.001) to maintain their patency. The overall effect of this strategy was to double the proportion of patients dialyzing with a fistula in our population from 16 to 34% (P < 0.001).ConclusionsRoutine preoperative vascular mapping results in a marked increase in placement of AV fistulas, as well as an improvement in the adequacy of forearm fistulas for dialysis. This approach resulted in a substantial increase in the proportion of patients dialyzing with a fistula in our patient population. Fistulas have a higher primary failure rate than grafts, but have a lower subsequent failure rate and require fewer procedures to maintain their long-term patency

Follow-Up in Aphasia Caused by Acute Stroke in a Prospective, Randomized, Clinical, and Experimental Controlled Noninvasive Study With an iPad-Based App (Neolexon®): Study Protocol of the Lexi Study

Rationale: Treatment of aphasia is still challenging for clinicians and patients. So far, there is proven evidence for “face-to-face” speech therapy. However, the digital age potentially offers new and complementary strategies that may add to treatment outcome in a cost-effective way. Neolexon® is a commercial tablet-based software for treatment of aphasia, which can be applied with the help of a therapist or as self-training by the patient. Aims and hypothesis: In the Lexi study, we aim to determine whether treatment with Neolexon® is superior to standard therapy in acute post-stroke aphasia. Sample size estimates: A sample size of 180 patients, 90 for each group, will be included with an assumed dropout rate of ~20%. Methods and design: Prospective, randomized, parallel group, open-label, blinded-endpoint clinical, and experimental controlled non-invasive trial (PROBE). Adult German native speakers with acute aphasia after stroke are included. Computer-generated, blocked, and stratified randomization by aphasia severity will assign patients to one of two groups: 4 weeks of either standard logopedic speech therapy or logopedic speech therapy with the app version of Neolexon®. Both groups will be instructed in self-training: the frequency and duration of self-training will be documented. Screening for aphasia will be performed using the Language Screening Test (LAST). The severity of aphasia in general and in subitems will be assessed using the Bielefelder Aphasie Screening (BIAS) and the Aphasia Check List (ACL). Follow-up will be assessed after 3 months. Study outcomes: Based on the consensus in our study team, we considered a 10% mean difference in the change of percentile rank (PR) of BIAS to be a minimal and clinically important difference. The primary endpoint is defined as a significant difference in BIAS comparing the two groups. Differences in quality of life, Beck Depression Inventory (BDI), and modified Ranking Scale (mRS) will be evaluated as secondary outcome parameters. Discussion: This trial will determine whether speech therapy with the use of Neolexon® is superior to standard logopedic therapy. Subgroups with the greatest response to Neolexon® will be described. The trial was prospectively registered on the “EU Clinical Trials Register” (NCT04080817)

Cardioprotective Effects of Cell Permeable NADPH oxidase inhibitors in Myocardial Ischemia/Reperfusion Injury

During myocardial ischemia/reperfusion (I/R), the generation of reactive oxygen species (ROS) contributes to post-reperfused cardiac injury and contractile dysfunction. Activation of NADPH oxidase (NOX) during reperfusion generates ROS, and exacerbates I/R injury. We hypothesize that reducing ROS formation through inhibition of NOX will attenuate myocardial I/R injury in isolated perfused rat hearts subjected to I(30min)/R(45min) compared to untreated I/R hearts. The cell-permeable NOX inhibiting peptide, gp91 ds/tat (RKKRRQRRR-CSTRIRRQL-Amide, MW=2452 g/mol, 20μM, n=5), significantly improved post-reperfused cardiac function compared to controls (n=15,

Daily to decadal modulation of jet variability

The variance of a jet’s position in latitude is found to be related to its average speed: when a jet becomes stronger its variability in latitude decreases. This relationship is shown to hold for observed midlatitude jets around the world and also across a hierarchy of numerical models. North Atlantic jet variability is shown to be modulated on decadal timescales, with decades of a strong, steady jet being interspersed with decades of a weak, variable jet. These modulations are also related to variations in the basin-wide occurrence of high-impact blocking events. A picture emerges of complex multidecadal jet variability in which recent decades do not appear unusual. We propose an underlying barotropic mechanism to explain this behaviour, related to the change in refractive properties of a jet as it strengthens, and the subsequent effect on the distribution of Rossby wave breaking