Survey of Materials for Nanoskiving and Influence of the Cutting Process on the Nanostructures Produced

This paper examines the factors that influence the quality of nanostructures fabricated by sectioning thin films with an ultramicrotome (“nanoskiving”). It surveys different materials (metals, ceramics, semiconductors, and conjugated polymers), deposition techniques (evaporation, sputter deposition, electroless deposition, chemical-vapor deposition, solution-phase synthesis, and spin-coating), and geometries (nanowires or two-dimensional arrays of rings and crescents). It then correlates the extent of fragmentation of the nanostructures with the composition of the thin films, the methods used to deposit them, and the parameters used for sectioning. There are four major conclusions. (i) Films of soft and compliant metals (those that have bulk values of hardness less than or equal to those of palladium, or ≤500 MPa) tend to remain intact upon sectioning, whereas hard and stiff metals (those that have values of hardness greater than or equal to those of platinum, or ≥500 MPa) tend to fragment. (ii) All conjugated polymers tested form intact nanostructures. (iii) The extent of fragmentation is lowest when the direction of cutting is perpendicular to the exposed edge of the embedded film. (iv) The speed of cutting−from 0.1 to 8 mm/s−has no effect on the frequency of defects. Defects generated during sectioning include scoring from defects in the knife, delamination of the film from the matrix, and compression of the matrix. The materials tested were: aluminum, titanium, nickel, copper, palladium, silver, platinum, gold, lead, bismuth, germanium, silicon dioxide ($\textrm{SiO}_2$), alumina ($\textrm{Al}_2\textrm{O}_3$), tin-doped indium oxide (ITO), lead sulfide nanocrystals, the semiconducting polymers poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV), poly(3-hexylthiophene) (P3HT), and poly(benzimidazobenzophenanthroline ladder) (BBL), and the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS).Chemistry and Chemical Biolog

Hole motion in the Ising antiferromagnet: an application of the recursion method

We study hole motion in the Ising antiferromagnet using the recursion method. Using the retraceable path approximation we find the hole's Green's function as well as its wavefunction for arbitrary values of $t/J_z$. The effect of small transverse interaction also is taken into account. Our results provide some additional insight into the self-consistent Born approximation.Comment: 8 pages, RevTex, no figures. Accepted for publication in Phys.Rev.

Identifying the quark content of the isoscalar scalar mesons f_0(980), f_0(1370), and f_0(1500) from weak and electromagnetic processes

The assignments of the isoscalar scalar mesons f0(980), f0(1370), and f0(1500) in terms of their qqbar substructure is still a matter of heated dispute. Here we employ the weak and electromagnetic decays D(s)(+) to f0+pi(+) and f0 two-photon decays, respectively, to identify the f0(980) and f0(1500) as mostly ssbar, and the f0(1370) as dominantly nonstrange, in agreement with previous work. The two-photon decays can be satisfactorily described with quark as well as with meson loops, though the latter ones provide a less model-dependent and more quantitative description.Comment: v1, 15 pages, plain LaTeX, 1 eps figure. v2, 18 pages, plain LaTeX (figure included). More discussion, especially on the f0(1370) and its empirical two-photon widt

Robotic Tentacles with Three-Dimensional Mobility Based on Flexible Elastomers

Soft robotic tentacles that move in three dimensions upon pressurization are fabricated by composing flexible elastomers with different tensile strengths using soft lithographic molding. These actuators are able to grip complex shapes and manipulate delicate objects. Embedding functional components into these actuators (for example, a needle for delivering fluid, a video camera, and a suction cup) extends their capabilities.Engineering and Applied Science

Epidemiological trends and clinical outcomes of cryptococcosis in a medically insured population in the United States: a claims-based analysis from 2017 to 2019

Background: Emerging risk factors highlight the need for an updated understanding of cryptococcosis in the United States. Objective: Describe the epidemiological trends and clinical outcomes of cryptococcosis in three patient groups: people with HIV (PWH), non-HIV-infected and non-transplant (NHNT) patients, and patients with a history of solid organ transplantation. Methods: We utilized data from the Merative Medicaid Database to identify individuals aged 18 and above with cryptococcosis based on the International Classification of Diseases, Tenth Revision diagnosis codes from January 2017 to December 2019. Patients were stratified into PWH, NHNT patients, and transplant recipients according to Infectious Diseases Society of America guidelines. Baseline characteristics, types of cryptococcosis, hospitalization details, and in-hospital mortality rates were compared across groups. Results: Among 703 patients, 59.7% were PWH, 35.6% were NHNT, and 4.7% were transplant recipients. PWH were more likely to be younger, male, identify as Black, and have fewer comorbidities than patients in the NHNT and transplant groups. Notably, 24% of NHNT patients lacked comorbidities. Central nervous system, pulmonary, and disseminated cryptococcosis were most common overall (60%, 14%, and 11%, respectively). The incidence of cryptococcosis fluctuated throughout the study period. PWH accounted for over 50% of cases from June 2017 to June 2019, but this proportion decreased to 47% from July to December 2019. Among the 52% of patients requiring hospitalization, 61% were PWH and 35% were NHNT patients. PWH had longer hospital stays. In-hospital mortality at 90days was significantly higher in NHNT patients (22%) compared to PWH (7%) and transplant recipients (0%). One-year mortality remained lowest among PWH (8%) compared to NHNT patients (22%) and transplant recipients (13%). Conclusion: In this study, most cases of cryptococcosis were PWH. Interestingly, while the incidence remained relatively stable in PWH, it slightly increased in those without HIV by the end of the study period. Mortality was highest in NHNT patients

Diabetes Mellitus Type 2 as a Risk Factor and Outcome Modifier for Cryptococcosis in HIV Negative, Non-transplant Patients, a Propensity Score Match Analysis

Cryptococcosis is an opportunistic fungal infection of worldwide distribution with significant associated morbidity and mortality. HIV, organ transplantation, malignancy, cirrhosis, sarcoidosis, and immunosuppressive medications are established risk factors for cryptococcosis. Type 2 diabetes mellitus (DM2) has been hypothesized as a risk factor and an outcome modifier for cryptococcosis. We aimed to compare outcomes among HIV-negative, non-transplant (NHNT) patients with and without DM2. We queried a global research network to identify NHNT patients (n = 3280). We performed a propensity score-matched (PSM) analysis comparing clinical outcomes among cryptococcosis patients by DM status. We also characterize adults with cryptococcosis and DM2 as the only risk factor. After PSM, NHNT patients with DM2 were more likely to develop cognitive dysfunction [9% vs. 6%, OR 1.6; 95% CI (1.1–2.3); P = 0.01] but had similar mortality, hospitalization, ICU, and stroke risk after acquiring cryptococcosis when compared to NHNT patients without DM2. Pulmonary cryptococcosis was the most common site of infection. Among 44 cryptococcosis patients with DM2 as the only identifiable risk factor for disease, the annual incidence of cryptococcosis was 0.001%, with a prevalence of 0.002%. DM2 is associated with increased cognitive dysfunction risk in NHNT patients with cryptococcosis. It is rare for DM2 to be the only identified risk factor for developing cryptococcosis. Kidney disease, hyperglycemia, and immune dysfunction can increase the risk of cryptococcosis in patients with DM2

INtervention for Cognitive Reserve Enhancement in Delaying the Onset of Alzheimer\u27s Symptomatic Expression (INCREASE), a Randomized Controlled Trial: Rationale, Study Design, and Protocol

BACKGROUND: The course of Alzheimer\u27s disease (AD) includes a 10-20-year preclinical period with progressive accumulation of amyloid β (Aβ) plaques and neurofibrillary tangles in the absence of symptomatic cognitive or functional decline. The duration of this preclinical stage in part depends on the rate of pathologic progression, which is offset by compensatory mechanisms, referred to as cognitive reserve (CR). Comorbid medical conditions, psychosocial stressors, and inappropriate medication use may lower CR, hastening the onset of symptomatic AD. Here, we describe a randomized controlled trial (RCT) designed to test the efficacy of a medication therapy management (MTM) intervention to reduce inappropriate medication use, bolster cognitive reserve, and ultimately delay symptomatic AD. METHODS/DESIGN: Our study aims to enroll 90 non-demented community-dwelling adults ≥ 65 years of age. Participants will undergo positron emission tomography (PET) scans, measuring Aβ levels using standardized uptake value ratios (SUVr). Participants will be randomly assigned to MTM intervention or control, stratified by Aβ levels, and followed for 12 months via in-person and telephone visits. Outcomes of interest include: (1) medication appropriateness (measured with the Medication Appropriateness Index (MAI)); (2) scores from Trail Making Test B (TMTB), Montreal Cognitive Assessment (MoCA), and California Verbal Learning Test (CVLT); (3) perceived health status (measured with the SF-36). We will also evaluate pre- to post-intervention change in: (1) use of inappropriate medications as measured by MAI; 2) CR Change Score (CRCS), defined as the difference in scopolamine-challenged vs unchallenged cognitive scores at baseline and follow-up. Baseline Aβ SUVr will be used to examine the relative impact of preclinical AD (pAD) pathology on CRCS, as well as the interplay of amyloid burden with inappropriate medication use. DISCUSSION: This manuscript describes the protocol of INCREASE ( INtervention for Cognitive Reserve Enhancement in delaying the onset of Alzheimer\u27s Symptomatic Expression ): a randomized controlled trial that investigates the impact of deprescribing inappropriate medications and optimizing medication regimens on potentially delaying the onset of symptomatic AD and AD-related dementias. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02849639. Registered on 29 July 2016

Blood levels of lead and dental caries in permanent teeth

ObjectivesThe purpose of this study was to determine whether there is an association between lead exposure within the ages of 1- 4- years and dental caries in the permanent dentition between ages 9- 17 among Mexican youth.MethodsData were collected for the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort from a group of 490 children born and reared in Mexico City. Among ages 1- 4- years, blood lead levels were measured in micrograms of lead per deciliter of blood (μg/dL) and the presence of caries in adolescence was determined using the International Caries and Detection and Assessment System (ICDAS). The relationship between blood levels of lead and decayed, missing, or filled surfaces (DMFS) was examined using negative binomial regression. Covariates were selected based on previous studies and included age, gender, socioeconomic status, oral hygiene, body mass index, and diet. The nonlinear relationship between lead and DMFS was examined using smoothing splines.ResultsThe mean overall blood lead level (BLL) was 4.83- μg/dL (S.D. of 2.2). The mean overall caries level (DMFS) was 4.1. No statistically significant association was found between early childhood blood lead levels and dental caries in adolescence.ConclusionThis study shows a lack of association between exposure to lead between the ages of 1- 4- years of age and dental caries in permanent dentition later in life. Other covariates, such as age and sugar consumption, appeared to play a more prominent role in caries development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163870/1/jphd12384.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163870/2/jphd12384_am.pd

Capturing health and eating status through a nutritional perception screening questionnaire (NPSQ9) in a randomised internet-based personalised nutrition intervention : the Food4Me study

BACKGROUND: National guidelines emphasize healthy eating to promote wellbeing and prevention of non-communicable diseases. The perceived healthiness of food is determined by many factors affecting food intake. A positive perception of healthy eating has been shown to be associated with greater diet quality. Internet-based methodologies allow contact with large populations. Our present study aims to design and evaluate a short nutritional perception questionnaire, to be used as a screening tool for assessing nutritional status, and to predict an optimal level of personalisation in nutritional advice delivered via the Internet. METHODS: Data from all participants who were screened and then enrolled into the Food4Me proof-of-principle study (n = 2369) were used to determine the optimal items for inclusion in a novel screening tool, the Nutritional Perception Screening Questionnaire-9 (NPSQ9). Exploratory and confirmatory factor analyses were performed on anthropometric and biochemical data and on dietary indices acquired from participants who had completed the Food4Me dietary intervention (n = 1153). Baseline and intervention data were analysed using linear regression and linear mixed regression, respectively. RESULTS: A final model with 9 NPSQ items was validated against the dietary intervention data. NPSQ9 scores were inversely associated with BMI (β = -0.181, p < 0.001) and waist circumference (Β = -0.155, p < 0.001), and positively associated with total carotenoids (β = 0.198, p < 0.001), omega-3 fatty acid index (β = 0.155, p < 0.001), Healthy Eating Index (HEI) (β = 0.299, p < 0.001) and Mediterranean Diet Score (MDS) (β = 0. 279, p < 0.001). Findings from the longitudinal intervention study showed a greater reduction in BMI and improved dietary indices among participants with lower NPSQ9 scores. CONCLUSIONS: Healthy eating perceptions and dietary habits captured by the NPSQ9 score, based on nine questionnaire items, were associated with reduced body weight and improved diet quality. Likewise, participants with a lower score achieved greater health improvements than those with higher scores, in response to personalised advice, suggesting that NPSQ9 may be used for early evaluation of nutritional status and to tailor nutritional advice. TRIAL REGISTRATION: NCT01530139 .Peer reviewedFinal Published versio

Structural and Evolutionary Analyses Show Unique Stabilization Strategies in the Type IV Pili of Clostridium difficile

Type IV pili are produced by many pathogenic Gram-negative bacteria and are important for processes as diverse as twitching motility, biofilm formation, cellular adhesion and horizontal gene transfer. However, many Gram-positive species, including C. difficile, also produce Type IV pili. Here, we identify the major subunit of the Type IV pili of C. difficile, PilA1, and describe multiple three-dimensional structures of PilA1, demonstrating the diversity found in three strains of C. difficile. We also model the incorporation of both PilA1 and a minor pilin, PilJ, into the pilus fiber. Although PilA1 contains no cysteine residues, and therefore cannot form the disulfide bonds found in all Gram-negative Type IV pilins, it adopts unique strategies to achieve a typical pilin fold. The structures of PilA1 and PilJ exhibit similarities with the Type IVb pilins from Gram-negative bacteria that suggest that the Type IV pili of C. difficile are involved in microcolony formation