Biomimetic Sequence-Templating Approach toward a Multiscale Modulation of Chromogenic Polymer Properties.

Precision control via molecular structure over adaptive conjugated polymer properties in aqueous environments is critical for realizing their biomedical applications. Here, we unravel the dependence of amphiphilic peptide-polydiacetylene (PDA) conjugate properties on the characteristic steric and hydrophobic contributions within peptide segments that serve as a biomimetic template for diacetylene polymerization in water. We investigated the functional impacts of molecular volume and polarity changes brought by dipeptide substitution domains on the following peptide-PDA material properties at multiple length scales: supramolecular assembly behavior, chain conformation-dependent photophysical properties, cell-material interfacing, and for the first time, bulk electrical properties of their films processed in water. A library of peptide-PDAs with systematically varied sequences show that the contributions of steric effects predominantly influence the electronic structure and resulting trends in photophysical properties, while the interplay between size and hydrophobicity of individual residues becomes more significant for higher-order assemblies affecting bulk properties. This work demonstrates sequence-tunable molecular volume and polarity as synthetic handles to rationally modulate PDA material properties across length scales, providing insights into the programmability of biomimetic conjugated polymers with adaptive functionalities.

Development of a global urban greenness indicator dataset for 1,000+ cities.

Global climate change has sparked efforts to adapt to increasing temperatures, especially in urban areas that experience increased day and nighttime temperatures due to the urban heat island effect. The addition of greenspace has been suggested as a possible means for urban centers to respond to increasing urban temperatures. Thus, it is important for urban planning and policymakers to have access to data on greenspace specific at a fine spatial resolution. This dataset consists of information on peak and annual average 1 × 1 km Normalized Difference Vegetation Index (NDVI) for over 1,000 global urban centers, which is an objective satellite-based measure of vegetation. Population-weighted values for both peak and annual average NDVI and include an indicator of greenness, with seven levels ranging from extremely low to extremely high are provided. Additional information regarding the climate zone (using the Köppen-Geiger climate classification) and level of development (using the Human Development Index or HDI) for each city is included. Analyses were repeated in 2010, 2015, and 2020 to provide the ability to track urban greenness over time. Data are provided in tabular format with summaries presented in both tables and graphics. These data can be used to inform policy and planning and can be used as an indicator for a variety of climate and health investigations.

Shining a light on the pathogenicity of health care providers' mobile phones: Use of a novel ultraviolet-C wave disinfection device.

BACKGROUND: Mobile phones are known to carry pathogenic bacteria and viruses on their surfaces, posing a risk to healthcare providers (HCPs) and hospital infection prevention efforts. We utilize an Ultraviolet-C (UV-C) device to provide an effective method for mobile phone disinfection and survey HCPs about infection risk. METHODS: Environmental swabs were used to culture HCPs' personal mobile phone surfaces. Four cultures were obtained per phone: before and after the UV-C device's 30-second disinfecting cycle, at the beginning and end of a 12-hour shift. Surveys were administered to participants pre- and poststudy. RESULTS: Total bacterial colony forming units were reduced by 90.5% (P = .006) after one UV-C disinfection cycle, and by 99.9% (P = .004) after 2 cycles. Total pathogenic bacterial colony forming units were decreased by 98.2% (P = .038) after one and >99.99% (P = .037) after 2 disinfection cycles. All survey respondents were willing to use the UV-C device daily to weekly, finding it convenient and beneficial. DISCUSSION: This novel UV-C disinfecting device is effective in reducing pathogenic bacteria on mobile phones. HCPs would frequently use a phone disinfecting device to reduce infection risk. CONCLUSIONS: In light of the ongoing coronavirus (COVID-19) pandemic, a standardized approach to phone disinfection may be valuable in preventing healthcare-associated infections.

Exploring the mental representation underlying familiarity assessment.

A new method was used to explore the role of perceptual information in familiarity-based recognition. The method uses a pairwise recognition task to compare recognition judgments to a test word when that word is related and unrelated to an immediately preceding word. If the false-alarm rate to the test word is greater when the two words are related, this is interpreted as reflecting an increase in the likelihood of positive familiarity assessment to the test word (Ngo, C. T., Sargent, J., & Dopkins, S. [2007]. Level of discrimination for recognition judgments reduced following the recognition of semantically related words. Journal of Memory and Language, 57, 415-436. doi:10.1016/j.jml.2007.05.007). The occurrence of such an increase for a given sort of preceding word-test word relatedness is taken as indicating that information of the sort in question is involved in familiarity-based recognition. Whereas previous work with this method has failed to find evidence that perceptual information is involved in familiarity-based recognition, the present study observed such evidence, under conditions in which previous work with other methods suggested that perceptual information would be likely to be involved in familiarity-based recognition. Thus, the study helped to validate the method and produced converging evidence that perceptual information is sometimes involved in familiarity-based recognition. The results of the study suggest that perceptual information is more likely to be involved in familiarity-based recognition when the lists for the recognition task are short.

Head-to-head comparison of practice with endoscopic retrograde cholangiopancreatography computer and mechanical simulators by experienced endoscopists and trainees.

BACKGROUND AND AIM: The endoscopic retrograde cholangiopancreatography (ERCP) mechanical simulator (EMS) and computer simulator (ECS) are described herein. No direct hands-on comparison has been reported to reflect the perception of trainers and trainees regarding the efficacy of each model for trainee ERCP education. We compared the trainers' and trainees' assessments of the EMS and ECS for trainee education. METHODS: Eighteen gastrointestinal trainees and 16 trainers with varying ERCP experience completed a questionnaire survey before and after practice with each simulator at hands-on ERCP practice workshops. They carried out scope insertion, selective bile duct cannulation, guidewire negotiation of a bile duct stricture, biliary papillotomy and insertion of a single biliary stent using both simulators. Main outcome measurement was respondents' assessments of comparative efficacy of EMS and ECS practice for trainee education. RESULTS: Compared to pre-practice evaluation, both EMS and ECS received higher scores after hands-on practice. Both trainers and trainees showed significantly greater increases in scores for EMS when compared with ECS in facilitating understanding of ERCP procedure, enhancing confidence in carrying out ERCP and the simulator as a credible option for supplementing clinical ERCP training (P < 0.05). Participants also scored EMS significantly higher in realism and usefulness as an instructional tool. CONCLUSIONS: Both computer and mechanical simulators are accepted modalities for ERCP training. The current data (based on a head-to-head comparison of hands-on practice experience) indicate EMS practice is rated higher than ECS practice in supplementing clinical ERCP training. EMS offers the additional advantage of coordinated practice with real equipment and accessories.

Effects of hyperglycemia and effects of ketosis on cerebral perfusion, cerebral water distribution, and cerebral metabolism.

Diabetic ketoacidosis (DKA) may cause brain injuries in children. The mechanisms responsible are difficult to elucidate because DKA involves multiple metabolic derangements. We aimed to determine the independent effects of hyperglycemia and ketosis on cerebral metabolism, blood flow, and water distribution. We used magnetic resonance spectroscopy to measure ratios of cerebral metabolites (ATP to inorganic phosphate [Pi], phosphocreatine [PCr] to Pi, N-acetyl aspartate [NAA] to creatine [Cr], and lactate to Cr) and diffusion-weighted imaging and perfusion-weighted imaging to assess cerebral water distribution (apparent diffusion coefficient [ADC] values) and cerebral blood flow (CBF) in three groups of juvenile rats (hyperglycemic, ketotic, and normal control). ATP-to-Pi ratio was reduced in both hyperglycemic and ketotic rats in comparison with controls. PCr-to-Pi ratio was reduced in the ketotic group, and there was a trend toward reduction in the hyperglycemic group. No significant differences were observed in NAA-to-Cr or lactate-to-Cr ratio. Cortical ADC was reduced in both groups (indicating brain cell swelling). Cortical CBF was also reduced in both groups. We conclude that both hyperglycemia and ketosis independently cause reductions in cerebral high-energy phosphates, CBF, and cortical ADC values. These effects may play a role in the pathophysiology of DKA-related brain injury.

Indigocarmine added to the water exchange method enhances adenoma detection - a RCT.

PURPOSE: Chromoendoscopy with dye spray and the water method both increase adenoma detection. HYPOTHESIS: Adding indigocarmine to the water method will enhance further the effectiveness of the latter in adenoma detection. METHODS: Screening colonoscopy was performed with the water method (control) or with 0.008% indigocarmine added (study) by two endoscopists. Randomization was based on computer-generated codes contained in blocks of pre-arranged opaque sealed envelopes. High resolution colonoscopes were used. Upon insertion into the rectum, air was suctioned. With the air pump turned off, water was infused using a blunt needle adaptor connected to the scope channel and a foot pump to facilitate scope insertion until the cecum was reached. Residual stool causing cloudiness was suctioned followed by infusion of clear or colored water (water exchange) to facilitate scope passage with minimal distention of the colonic lumen. Upon seeing the appendix opening under water, water was suctioned and air was insufflated to facilitate inspection on scope withdrawal. STATISTICS: Sample size calculation revealed 168 patients (84/group) needed to be randomized. Study was IRB-approved and registered (NCT01383265). RESULTS: There were no significant differences in mean age, gender distribution, BMI, and family history of colon cancer. Cecal intubation success rate was 100% in both groups. The overall adenoma detection rate was 44% (water only) versus 62% (water with indigocarmine), respectively (p=0.03). One cancer was detected in each group. CONCLUSION: In a RCT, indigocarmine at 0.008% concentration, added to the water method, significantly enhanced further the effectiveness of the latter in detecting adenomas.

Interim report of a randomized cross-over study comparing clinical performance of novice trainee endoscopists using conventional air insufflation versus warm water infusion colonoscopy.

BACKGROUND: The applicability of water method colonoscopy in trainee education is not known. AIM: To compare the water method vs. usual air method in teaching novice trainee colonoscopy. METHOD: An IRB approved prospective randomized cross-over study (NCT01482546) in a university setting with diverse patient population. DESIGN: Three first year GI fellows consented to participate in the study. Trainees were randomized to learn with either usual air method or the water method in performing colonoscopy with a dedicated endoscopy attending during their weekly outpatient endoscopy clinics for the initial six months of training and then cross-over to the other method for the remaining six months. PATIENTS: Patients undergoing screening, surveillance or diagnostic colonoscopy. RESULTS: The interim data revealed no significant difference in age, gender, and body mass index (BMI). Trainees rated the water method colonoscopy as significantly easier to learn compared to the air method (p=0.007). CONCLUSIONS: The interim data demonstrate positive effects of using the water method in training novice endoscopists who reported a significant ease of learning colonoscopy using this method. Training programs could consider joining us in evaluating the use of warm water infusion in colonoscopy education.

Retrospective analysis showing the water method increased adenoma detection rate - a hypothesis generating observation.

BACKGROUND: A water method developed to attenuate discomfort during colonoscopy enhanced cecal intubation in unsedated patients. Serendipitously a numerically increased adenoma detection rate (ADR) was noted. OBJECTIVE: To explore databases of sedated patients examined by the air and water methods to identify hypothesis-generating findings. DESIGN: Retrospective analysis. SETTING: VA endoscopy center. PATIENTS: creening colonoscopy. INTERVENTIONS: From 1/2000-6/2006 the air method was used - judicious air insufflation to permit visualization of the lumen to aid colonoscope insertion and water spray for washing mucosal surfaces. From 6/2006-11/2009 the water method was adopted - warm water infusion in lieu of air insufflation and suction removal of residual air to aid colonoscope insertion. During colonoscope withdrawal adequate air was insufflated to distend the colonic lumen for inspection, biopsy and polypectomy in a similar fashion in both periods. Main outcome measurements: ADR. RESULTS: The air (n=683) vs. water (n=495) method comparisons revealed significant differences in overall ADR 26.8% (183 of 683) vs. 34.9% (173 of 495) and ADR of adenomas >9 mm, 7.2% vs. 13.7%, respectively (both P<0.05, Fisher's exact test). LIMITATIONS: Non-randomized data susceptible to bias by unmeasured parameters unrelated to the methods. CONCLUSION: Confirmation of the serendipitous observation of an impact of the water method on ADR provides impetus to call for randomized controlled trials to test hypotheses related to the water method as an approach to improving adenoma detection. Because of recent concerns over missed lesions during colonoscopy, the provocative hypothesis-generating observations warrant presentation.

Efficient targeted gene disruption in the soma and germ line of the frog Xenopus tropicalis using engineered zinc-finger nucleases.

The frog Xenopus, an important research organism in cell and developmental biology, currently lacks tools for targeted mutagenesis. Here, we address this problem by genome editing with zinc-finger nucleases (ZFNs). ZFNs directed against an eGFP transgene in Xenopus tropicalis induced mutations consistent with nonhomologous end joining at the target site, resulting in mosaic loss of the fluorescence phenotype at high frequencies. ZFNs directed against the noggin gene produced tadpoles and adult animals carrying up to 47% disrupted alleles, and founder animals yielded progeny carrying insertions and deletions in the noggin gene with no indication of off-target effects. Furthermore, functional tests demonstrated an allelic series of activity between three germ-line mutant alleles. Because ZFNs can be designed against any locus, our data provide a generally applicable protocol for gene disruption in Xenopus.

Superficial Priming in Episodic Recognition.

We explored the effect of superficial priming in episodic recognition and found it to be different from the effect of semantic priming in episodic recognition. Participants made recognition judgments to pairs of items, with each pair consisting of a prime item and a test item. Correct positive responses to the test item were impeded if the prime and test item were superficially related; this was the case when the items were words and the crucial relationship was phonological and orthographic as well as when the items were letter strings and the crucial relationship was orthographic. The results of further experiments suggested that the priming effect cannot be attributed to a process of discounting or to habituation in a familiarity assessment process.

Effects of conceptual processing on familiarity-based recognition.

Two experiments compared the impact of conceptual and perceptual processing at encoding on the familiarity-based recognition of items without preexisting conceptual representations. The stimuli for the experiments were visual designs and nonsense letter strings. The process dissociation procedure was used in conjunction with the process dissociation equations and the Dual Process Signal Detection model to assess the contributions of familiarity-based recognition and recollection in the recognition of the stimuli. A conceptual processing advantage was observed in both experiments: familiarity-based recognition was enhanced more by conceptual than by perceptual processing at encoding. It is suggested that the results may be problematic for the view that conceptual priming underlies the conceptual processing advantage.

The bias for a recognition judgement depends on the response emitted in a prior recognition judgement.

On each trial of the experimental procedure the participant read a list of words and made successive recognition judgements to multiple test words. The bias for a given recognition judgement was more conservative if the judgement followed a correct positive response to a target than if it followed a correct negative response to a lure. Similar results were not observed for successive semantic recognition judgements. The bias shift was greater when the study list was short than when the list was long. The results suggest that participants in a recognition task have a sense of the size of the set of targets that might possibly be presented on the next trial and that, under conditions in which a word can only be presented once during the test phase, their bias becomes more conservative after a positive response to a target because the set is depleted.

Rapid gynogenetic mapping of Xenopus tropicalis mutations to chromosomes.

Pilot forward genetic screens in Xenopus tropicalis have isolated over 60 recessive mutations. Here we present a simple method for mapping mutations to chromosomes using gynogenesis and centromeric markers. When coupled with available genomic resources, gross mapping facilitates evaluation of candidate genes as well as higher resolution linkage studies. Using gynogenesis, we have mapped the genetic locations of the 10 X. tropicalis centromeres, and performed fluorescence in situ hybridization to validate these locations cytologically. We demonstrate the use of this very small set of centromeric markers to map mutations efficiently to specific chromosomes. Developmental Dynamics 238:1398-1406, 2009. (c) 2009 Wiley-Liss, Inc.

Heritable targeted gene disruption in zebrafish using designed zinc-finger nucleases.

We describe the use of zinc-finger nucleases (ZFNs) for somatic and germline disruption of genes in zebrafish (Danio rerio), in which targeted mutagenesis was previously intractable. ZFNs induce a targeted double-strand break in the genome that is repaired to generate small insertions and deletions. We designed ZFNs targeting the zebrafish golden and no tail/Brachyury (ntl) genes and developed a budding yeast-based assay to identify the most active ZFNs for use in vivo. Injection of ZFN-encoding mRNA into one-cell embryos yielded a high percentage of animals carrying distinct mutations at the ZFN-specified position and exhibiting expected loss-of-function phenotypes. Over half the ZFN mRNA-injected founder animals transmitted disrupted ntl alleles at frequencies averaging 20%. The frequency and precision of gene-disruption events observed suggest that this approach should be applicable to any loci in zebrafish or in other organisms that allow mRNA delivery into the fertilized egg.

Level of Discrimination for Recognition Judgments Reduced following the Recognition of Semantically Related Words.

Participants read lists of words and then made recognition judgments to pairs of words, each of which consisted of a prime word and a test word. At issue was the effect of a semantic relationship between the prime word and the test word on the recognition judgment to the test word. Under standard recognition conditions, semantic priming impeded correct recognition judgments to new test words and had no effect on recognition judgments to old test words. The overall effect was to reduce the level of discrimination for recognition judgments to the test word. Under conditions in which familiarity assessment would be expected to play a greater role in judgments to old test words, semantic priming facilitated those judgments. The results are explained in terms of a dual process account of recognition.

The Role of Recognition Memory in Anaphor Identification.

In studies of anaphor comprehension, the capacity for recognizing a noun in a sentence decreases following the resolution of a repeated-noun anaphor (Gernsbacher, 1989). In studies of recognition memory, the capacity for recognizing a noun in a scrambled sentence decreases following the recognition that another noun has occurred before in the scrambled sentence (Dopkins & Ngo, 2002). The results of the present study suggest that these two phenomena reflect the same recognition memory process. The results suggest further that this is not because participants in studies of anaphor comprehension ignore the discourse properties of the stimulus materials and treat them as lists of words upon which memory tests are to be given. These results suggest that recognition processes play a role in anaphor comprehension and that such processes are in part the means by which repeated-noun anaphors are identified as such.

Loss of distinctive features and a broader pattern of priming in Alzheimer's disease.

The results of 2 experiments support the contention that patients with Alzheimer's disease (AD) show a relative loss of the semantic features that distinguish concepts from one another and that the representations of pairs of concepts consequently share a larger proportion of their associated features in AD than in normal aging. In Experiment 1, AD patients listed fewer features for a set of concepts than did healthy older adults and were more deficient at listing features if the features were distinctive to particular concepts than if they were shared by multiple concepts. In Experiment 2, AD patients showed online priming at levels of relatedness at which healthy older adults did not.