Fast and Accurate Coarsening Simulation with an Unconditionally Stable Time Step

We present Cahn-Hilliard and Allen-Cahn numerical integration algorithms that are unconditionally stable and so provide significantly faster accuracy-controlled simulation. Our stability analysis is based on Eyre's theorem and unconditional von Neumann stability analysis, both of which we present. Numerical tests confirm the accuracy of the von Neumann approach, which is straightforward and should be widely applicable in phase-field modeling. We show that accuracy can be controlled with an unbounded time step Delta-t that grows with time t as Delta-t ~ t^alpha. We develop a classification scheme for the step exponent alpha and demonstrate that a class of simple linear algorithms gives alpha=1/3. For this class the speed up relative to a fixed time step grows with the linear size of the system as N/log N, and we estimate conservatively that an 8192^2 lattice can be integrated 300 times faster than with the Euler method.Comment: 14 pages, 6 figure

Salicylaldehyde hydrazones: buttressing of outer sphere hydrogen-bonding and copper-extraction properties

Salicylaldehyde hydrazones are weaker copper extractants than their oxime derivatives, which are used in hydrometallurgical processes to recover ~20 % of the world’s copper. Their strength, based on the extraction equilibrium constant Ke, can be increased by nearly three orders of magnitude by incorporating electron-withdrawing or hydrogen-bond acceptor groups (X) ortho to the phenolic OH group of the salicylaldehyde unit. Density functional theory calculations suggest that the effects of the 3-X substituents arise from a combination of their influence on the acidity of the phenol in the pH-dependent equilibrium, Cu2+ + 2Lorg ⇌ [Cu(L–H)2]org + 2H+, and on their ability to ‘buttress’ interligand hydrogen bonding by interacting with the hydrazone N–H donor group. X-ray crystal structure determination and computed structures indicate that in both the solid state and the gas phase, coordinated hydrazone groups are less planar than coordinated oximes and this has an adverse effect on intramolecular hydrogen-bond formation to the neighbouring phenolate oxygen atoms

Improving the diagnostic yield of high-resolution esophageal manometry for GERD: The straight leg-raise international study

BACKGROUND & AIMS: The straight leg raise (SLR) maneuver during high-resolution manometry (HRM) can assess esophagogastric junction (EGJ) barrier function by measuring changes in intraesophageal pressure (IEP) when intra-abdominal pressure is increased. We aimed to determine whether increased esophageal pressure during SLR predicts pathologic esophageal acid exposure time (AET). METHODS: Adult patients with persistent gastroesophageal reflux disease (GERD) symptoms undergoing HRM and pH-impedance or wireless pH study off proton pump inhibitor were prospectively studied between July 2021 and March 2022. After the HRM Chicago 4.0 protocol, patients were requested to elevate 1 leg at 45º for 5 seconds while supine. The SLR maneuver was considered effective when intra-abdominal pressure increased by 50%. IEPs were recorded 5 cm above the lower esophageal sphincter at baseline and during SLR. GERD was defined as AET greater than 6%. RESULTS: The SLR was effective in 295 patients (81%), 115 (39%) of whom had an AET greater than 6%. Hiatal hernia (EGJ type 2 or 3) was seen in 135 (46%) patients. Compared with patients with an AET less than 6%, peak IEP during SLR was significantly higher in the GERD group (29.7 vs 13.9 mm Hg; P \u3c .001). Using receiver operating characteristic analysis, an increase of 11 mm Hg of peak IEP from baseline during SLR was the optimal cut-off value to predict an AET greater than 6% (area under the receiver operating characteristic curve, 0.84; sensitivity, 79%; and specificity, 85%), regardless of the presence of hiatal hernia. On multivariable analysis, an IEP pressure increase during the SLR maneuver, EGJ contractile integral, EGJ subtype 2, and EGJ subtype 3, were found to be significant predictors of AET greater than 6% CONCLUSIONS: The SLR maneuver can predict abnormal an AET, thereby increasing the diagnostic value of HRM when GERD is suspected. CLINICALTRIALS: gov ID: NCT04813029

Determining epigenetic memory in kidney proximal tubule cell derived induced pluripotent stem cells using a quadruple transgenic reprogrammable mouse

The majority of nucleated somatic cells can be reprogrammed to induced pluripotent stem cells (iPSCs). The process of reprogramming involves epigenetic remodelling to turn on pluripotency-associated genes and turn off lineage-specific genes. Some evidence shows that iPSCs retain epigenetic marks of their cell of origin and this epigenetic memory influences their differentiation potential, with a preference towards their cell of origin. Here, we reprogrammed proximal tubule cells (PTC) and tail tip fibroblasts (TTF), from a reprogrammable mouse to iPSCs and differentiated the iPSCs to renal progenitors to understand if epigenetic memory plays a role in renal differentiation. This model allowed us to eliminate experimental variability due to donor genetic differences and transfection of the reprogramming factors such as copy number and integration site. In this study we demonstrated that early passage PTC iPSCs and TTF iPSCs expressed low levels of renal progenitor genes and high levels of pluripotency-associated genes, and the transcriptional levels of these genes were not significantly different between PTC iPSCs and TTF iPSCs. We used ChIP-seq of H3K4me3, H3K27me3, H3K36me3 and global DNA methylation profiles of PTC iPSCs and TTF iPSCs to demonstrate that global epigenetic marks were not different between the cells from the two different sets of tissue samples. There were also no epigenetic differences observed when kidney developmental genes and pluripotency-associated genes were closely examined. We did observe that during differentiation to renal progenitor cells the PTC iPSC-derived renal cells expressed higher levels of three renal progenitor genes compared to progenitors derived from TTF iPSCs but the underlying DNA methylation and histone methylation patterns did not suggest an epigenetic memory basis for this

Chemical History with a Nuclear Microprobe

A nuclear microprobe cannot give direct information on the chemical state of an element, but the spatial distribution of elements in a specimen is often determined by the chemical history of the sample. Fuel cells and minerals are examples of complex systems whose elemental distributions are determined by past chemical history. The distribution of catalyst in used fuel cell electrodes provides direct information on the chemical stability of dispersed catalysts under operating conditions. We have used spatially resolved Rutherford backscattering to measure the migration of platinum and vanadium from intermetallic catalysts and to determine their suitability for use under the extreme operating conditions found in phosphoric acid fuel cells. Geologic materials are complex, heterogeneous samples with small mineral grains. The trace element distribution within the individual mineral grains and between different mineral phases is sensitive to the details of the mineral formation and history. The spatial resolution and sub-100-ppm sensitivity available with a nuclear microprobe open up several new classes of experiments to the geochemist. Geochemistry and electrochemistry are two areas proving particularly fruitful for application of the nuclear microprobe

Clinical Factors Associated with the Non-Operative Airway Management of Patients with Robin Sequence.

BACKGROUND: The indications for surgical airway management in patients with Robin sequence (RS) and severe airway obstruction have not been well defined. While certain patients with RS clearly require surgical airway intervention and other patients just as clearly can be managed with conservative measures alone, a significant proportion of patients with RS present with a more confusing and ambiguous clinical course. The purpose of this study was to describe the clinical features and objective findings of patients with RS whose airways were successfully managed without surgical intervention. METHODS: The authors retrospectively reviewed the medical charts of infants with RS evaluated for potential surgical airway management between 1994 and 2014. Patients who were successfully managed without surgical intervention were included. Patient demographics, nutritional and respiratory status, laboratory values, and polysomnography (PSG) findings were recorded. RESULTS: Thirty-two infants met the inclusion criteria. The average hospital stay was 16.8 days (range, 5-70 days). Oxygen desaturation ( CONCLUSIONS: Nonsurgical airway management was successful in patients who demonstrated consistent weight gain and mild to moderate obstruction on PSG, with a mean AHI of/hour

The California-Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars

We present stellar and planetary properties for 1305 Kepler Objects of Interest (KOIs) hosting 2025 planet candidates observed as part of the California-Kepler Survey. We combine spectroscopic constraints, presented in Paper I, with stellar interior modeling to estimate stellar masses, radii, and ages. Stellar radii are typically constrained to 11%, compared to 40% when only photometric constraints are used. Stellar masses are constrained to 4%, and ages are constrained to 30%. We verify the integrity of the stellar parameters through comparisons with asteroseismic studies and Gaia parallaxes. We also recompute planetary radii for 2025 planet candidates. Because knowledge of planetary radii is often limited by uncertainties in stellar size, we improve the uncertainties in planet radii from typically 42% to 12%. We also leverage improved knowledge of stellar effective temperature to recompute incident stellar fluxes for the planets, now precise to 21%, compared to a factor of two when derived from photometry.Comment: 13 pages, 4 figures, 4 tables, accepted for publication in AJ; full versions of tables 3 and 4 are include

The Influence of Overbuilt Versus Game-Permitted American Football Facemasks on Peripheral Visuomotor Ability in NCAA Division I Football Athletes

Topics in Exercise Science and Kinesiology Volume 2: Issue 1, Article 9, 2021. Heavier facemask reinforcement has been shown to impair reaction time. While overbuilt facemasks are illegal for gameplay at all levels of competition, empirical rationale for this has not be realized and it is unknown if overbuilt facemasks are worse for peripheral vision than permitted ones. Thus, the purpose of this study was to investigate the effects of wearing an overbuilt facemask versus game permitted facemasks on peripheral visuomotor ability in collegiate football players. Male NCAA Division I football players (n=18) completed a 60-second peripheral visuomotor test on a Dynavision D2 visuomotor board under the following conditions: 1) Baseline (No helmet), 2) Helmet + Light reinforced facemask, 3) Helmet + Medium reinforced facemask, 4) Helmet + Heavy reinforced facemask, 5) Helmet + Overbuilt facemask. Overall peripheral reaction time (PRT) and PRT separated by rings and quadrants were analyzed. Points of application: 1) Regardless of facemask reinforcement, wearing protective headgear impairs peripheral reaction time (PRT) compared to baseline with no helmet. Addition of an overbuilt facemask significantly impairs PRT compared to NCAA permitted facemasks. 2) An overbuilt facemask exhibits the most visuomotor decrement in far peripheral visual fields. 3) Decreases in visuomotor ability while wearing an overbuilt facemask are most pronounced in lower regions of visual field

The California-Kepler Survey. I. High Resolution Spectroscopy of 1305 Stars Hosting Kepler Transiting Planets

The California-Kepler Survey (CKS) is an observational program to improve our knowledge of the properties of stars found to host transiting planets by NASA's Kepler Mission. The improvement stems from new high-resolution optical spectra obtained using HIRES at the W. M. Keck Observatory. The CKS stellar sample comprises 1305 stars classified as Kepler Objects of Interest, hosting a total of 2075 transiting planets. The primary sample is magnitude-limited (Kp < 14.2) and contains 960 stars with 1385 planets. The sample was extended to include some fainter stars that host multiple planets, ultra short period planets, or habitable zone planets. The spectroscopic parameters were determined with two different codes, one based on template matching and the other on direct spectral synthesis using radiative transfer. We demonstrate a precision of 60 K in effective temperature, 0.10 dex in surface gravity, 0.04 dex in [Fe/H], and 1.0 km/s in projected rotational velocity. In this paper we describe the CKS project and present a uniform catalog of spectroscopic parameters. Subsequent papers in this series present catalogs of derived stellar properties such as mass, radius and age; revised planet properties; and statistical explorations of the ensemble. CKS is the largest survey to determine the properties of Kepler stars using a uniform set of high-resolution, high signal-to-noise ratio spectra. The HIRES spectra are available to the community for independent analyses.Comment: 20 pages, 19 figures, accepted for publication in AJ; a full version of Table 5 is included as tab_cks.csv and tab_cks.te

A journey to client and therapist mutuality in person-centered psychotherapy: a case study

This aim of this case study was to build theory on the development of client–therapist mutuality in person-centered psychotherapy. A case study focusing on a 42-year-old female client who had presented for therapy following trauma within interpersonal relationships has been used. A reflective, theory-building, case study method was adopted that used data gathered from verbatim session notes and research interviews between the therapist (first author) and research supervisor (second author). Three primary therapeutic processes that contributed to the development of mutuality are discussed. First, the development of mutual empathy in the relationship; second, strategies for disconnection and staying out of relationship are identified. Third, client agency and mutuality is explored. In conclusion the study proposes that mutuality is a key construct within person-centered psychotherapy and develops as a natural consequence of the presence of Rogers’ therapeutic conditions