2,645 research outputs found
Multicritical Points of Potts Spin Glasses on the Triangular Lattice
We predict the locations of several multicritical points of the Potts spin
glass model on the triangular lattice. In particular, continuous multicritical
lines, which consist of multicritical points, are obtained for two types of
two-state Potts (i.e., Ising) spin glasses with two- and three-body
interactions on the triangular lattice. These results provide us with numerous
examples to further verify the validity of the conjecture, which has succeeded
in deriving highly precise locations of multicritical points for several spin
glass models. The technique, called the direct triangular duality, a variant of
the ordinary duality transformation, directly relates the triangular lattice
with its dual triangular lattice in conjunction with the replica method.Comment: 18 pages, 2, figure
Improving Refrigerant Flammability Limit Test Methods Based on ASTM E681
An improved test method for refrigerant flammability limit measurements is presented. Such measurements are essential for determining the lower flammability limits of refrigerants, and thus their safety classifications. Predicated on expert interviews and experiments, several changes to ASTM E681 and related standards are recommended, as follows. The 12 L glass vessel should be replaced with transparent polycarbonate (or other transparent plastic) to eliminate etching by HF and to facilitate vessel penetrations. The orientation of the electrode supports and the temperature probe should be changed from vertical to horizontal to prevent flame quenching. Venting should not occur before the flame stops propagating near the vessel wall. All penetrations should be removed from the rubber stopper, it should be weighted for a total mass of 2.5 kg, and the initial pressure should be 90 kPa absolute. The flame angle should be plotted versus refrigerant concentration, whereby a least-squares line determines the flammability limit at a flame angle of 90°. Finally, the vessel pressure should be measured during each test to evaluate the pressure rise during flame propagation and to help identify the onset of venting. These changes are relatively easy to implement and they improve the test precision and reproducibility without significantly changing previously established flammability limits
Cell-free measurements of brightness of fluorescently labeled antibodies
Validation of imaging contrast agents, such as fluorescently labeled imaging antibodies, has been recognized as a critical challenge in clinical and preclinical studies. As the number of applications for imaging antibodies grows, these materials are increasingly being subjected to careful scrutiny. Antibody fluorescent brightness is one of the key parameters that is of critical importance. Direct measurements of the brightness with common spectroscopy methods are challenging, because the fluorescent properties of the imaging antibodies are highly sensitive to the methods of conjugation, degree of labeling, and contamination with free dyes. Traditional methods rely on cell-based assays that lack reproducibility and accuracy. In this manuscript, we present a novel and general approach for measuring the brightness using antibody-avid polystyrene beads and flow cytometry. As compared to a cell-based method, the described technique is rapid, quantitative, and highly reproducible. The proposed method requires less than ten microgram of sample and is applicable for optimizing synthetic conjugation procedures, testing commercial imaging antibodies, and performing high-throughput validation of conjugation procedures
Superconductivity in Cu_xTiSe_2
Charge density waves (CDWs) are periodic modulations of the conduction
electron density in solids. They are collective states that arise from
intrinsic instabilities often present in low dimensional electronic systems.
The layered dichalcogenides are the most well-studied examples, with TiSe_2 one
of the first CDW-bearing materials known. The competition between CDW and
superconducting collective electronic states at low temperatures has long been
held and explored, and yet no chemical system has been previously reported
where finely controlled chemical tuning allows this competition to be studied
in detail. Here we report how, upon controlled intercalation of TiSe_2 with Cu
to yield Cu_xTiSe_2, the CDW transition is continuously suppressed, and a new
superconducting state emerges near x = 0.04, with a maximum T_c of 4.15 K found
at x = 0.08. Cu_xTiSe_2 thus provides the first opportunity to study the CDW to
Superconductivity transition in detail through an easily-controllable chemical
parameter, and will provide new insights into the behavior of correlated
electron systems.Comment: Accepted to Nature Physic
Association of age with perioperative morbidity among patients undergoing surgical management of minor burns
INTRODUCTION: Burn injuries are associated with significant morbidity, often necessitating surgical management. Older patients are more prone to burns and more vulnerable to complications following major burns. While the relationship between senescence and major burns has already been thoroughly investigated, the role of age in minor burns remains unclear. To better understand differences between elderly and younger patients with predominantly minor burns, we analyzed a multi-institutional database.
METHODS: We reviewed the 2008-2020 ACS-NSQIP database to identify patients who had suffered burns according to ICD coding and underwent initial burn surgery.
RESULTS: We found 460 patients, of which 283 (62%) were male and 177 (38%) were female. The mean age of the study cohort was 46 ± 17 years, with nearly one-fourth (n = 108; 23%) of all patients being aged â„60 years. While the majority (n = 293; 64%) suffered from third-degree burns, 22% (n = 99) and 15% (n = 68) were diagnosed with second-degree burns and unspecified burns, respectively. An average operation time of 46 min, a low mortality rate of 0.2% (n = 1), a short mean length of hospital stay (1 day), and an equal distribution of in- and outpatient care (51%, n = 234 and 49%, n = 226, respectively) indicated that the vast majority of patients suffered from minor burns. Patients aged â„60 years showed a significantly prolonged length of hospital stay (p0.0001), creatinine (p>0.0001), white blood cell count (p=0.02), partial thromboplastin time (p = 0.004), and lower levels of albumin (p = 0.0009) and hematocrit (p>0.0001) were identified as risk factors for the occurrence of any complication. Further, complications were more frequent among patients with lower body burns.
DISCUSSION: In conclusion, patients â„60 years undergoing surgery for predominantly minor burns experienced significantly more complications. Minor lower body burns correlated with worse outcomes and a higher incidence of adverse events. Decreased levels of serum albumin and hematocrit and elevated values of blood urea nitrogen, creatinine, white blood count, and partial thromboplastin time were identified as predictive risk factors for complications
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Safety and efficacy of endoscopic submucosal dissection for rectal neoplasia: a multicenter North American experience.
Background and aims âRectal lesions traditionally represent the first lesions approached during endoscopic submucosal dissection (ESD) training in the West. We evaluated the safety and efficacy of rectal ESD in North America. Methods âThis is a multicenter retrospective analysis of rectal ESD between January 2010 and September 2018 in 15 centers. End points included: rates of en bloc resection, R0 resection, adverse events, comparison of pre- and post-ESD histology, and factors associated with failed resection. Results âIn total, 171 patients (median age 63 years; 56â% men) underwent rectal ESD (median size 43âmm). En bloc resection was achieved in 141 cases (82.5â%; 95â%CI 76.8-88.2), including 24 of 27 (88.9â%) with prior failed endoscopic mucosal resection (EMR). R0 resection rate was 74.9â% (95â%CI 68.4-81.4). Post-ESD bleeding and perforation occurred in 4 (2.3â%) and 7 (4.1â%), respectively. Covert submucosal invasive cancer (SMIC) was identified in 8.6â% of post-ESD specimens. There was one case (1/120; 0.8â%) of recurrence at a median follow-up of 31 weeks; IQR: 19-76 weeks). Older age and higher body mass index (BMI) were predictors of failed R0 resection, whereas submucosal fibrosis was associated with a higher likelihood of both failed en bloc and R0 resection. Conclusion âRectal ESD in North America is safe and is associated with high en bloc and R0 resection rates. The presence of submucosal fibrosis was the main predictor of failed en bloc and R0 resection. ESD can be considered for select rectal lesions, and serves not only to establish a definitive tissue diagnosis but also to provide curative resection for lesions with covert advanced disease
The Spitzer Survey of Stellar Structure in Galaxies (S^4G)
The Spitzer Survey of Stellar Structure in Galaxies S^4G is an Exploration
Science Legacy Program approved for the Spitzer post-cryogenic mission. It is a
volume-, magnitude-, and size-limited (d < 40 Mpc, |b| > 30 degrees, m_(Bcorr)
< 15.5, D25>1') survey of 2,331 galaxies using IRAC at 3.6 and 4.5 microns.
Each galaxy is observed for 240 s and mapped to > 1.5 x D25. The final
mosaicked images have a typical 1 sigma rms noise level of 0.0072 and 0.0093
MJy / sr at 3.6 and 4.5 microns, respectively. Our azimuthally-averaged surface
brightness profile typically traces isophotes at mu_3.6 (AB) (1 sigma) ~ 27 mag
arcsec^-2, equivalent to a stellar mass surface density of ~ 1 Msun pc^-2. S^4G
thus provides an unprecedented data set for the study of the distribution of
mass and stellar structures in the local Universe. This paper introduces the
survey, the data analysis pipeline and measurements for a first set of
galaxies, observed in both the cryogenic and warm mission phase of Spitzer. For
every galaxy we tabulate the galaxy diameter, position angle, axial ratio,
inclination at mu_3.6 (AB) = 25.5 and 26.5 mag arcsec^-2 (equivalent to ~ mu_B
(AB) =27.2 and 28.2 mag arcsec^-2, respectively). These measurements will form
the initial S^4G catalog of galaxy properties. We also measure the total
magnitude and the azimuthally-averaged radial profiles of ellipticity, position
angle, surface brightness and color. Finally, we deconstruct each galaxy using
GALFIT into its main constituent stellar components: the bulge/spheroid, disk,
bar, and nuclear point source, where necessary. Together these data products
will provide a comprehensive and definitive catalog of stellar structures, mass
and properties of galaxies in the nearby Universe.Comment: Accepted for Publication in PASP, 14 pages, 13 figure
The ATF6 pathway of the ER stress response contributes to enhanced viability in glioblastoma
Therapeutic resistance is a major barrier to improvement of outcomes for patients with glioblastoma. The endoplasmic reticulum stress response (ERSR) has been identified as a contributor to chemoresistance in glioblastoma; however the contributions of the ERSR to radioresistance have not been characterized. In this study we found that radiation can induce ER stress and downstream signaling associated with the ERSR. Induction of ER stress appears to be linked to changes in ROS balance secondary to irradiation. Furthermore, we observed global induction of genes downstream of the ERSR in irradiated glioblastoma. Knockdown of ATF6, a regulator of the ERSR, was sufficient to enhance radiation induced cell death. Also, we found that activation of ATF6 contributes to the radiation-induced upregulation of glucose regulated protein 78 (GRP78) and NOTCH1. Our results reveal ATF6 as a potential therapeutic target to enhance the efficacy of radiation therapy
OnâDemand Reconfiguration of Nanomaterials: When Electronics Meets Ionics
Rapid advances in the semiconductor industry, driven largely by device scaling, are now approaching fundamental physical limits and face severe power, performance, and cost constraints. Multifunctional materials and devices may lead to a paradigm shift toward new, intelligent, and efficient computing systems, and are being extensively studied. Herein examines how, by controlling the internal ion distribution in a solidâstate film, a materialâs chemical composition and physical properties can be reversibly reconfigured using an applied electric field, at room temperature and after device fabrication. Reconfigurability is observed in a wide range of materials, including commonly used dielectric films, and has led to the development of new device concepts such as resistive randomâaccess memory. Physical reconfigurability further allows memory and logic operations to be merged in the same device for efficient inâmemory computing and neuromorphic computing systems. By directly changing the chemical composition of the material, coupled electrical, optical, and magnetic effects can also be obtained. A survey of recent fundamental material and device studies that reveal the dynamic ionic processes is included, along with discussions on systematic modeling efforts, device and material challenges, and future research directions.By controlling the internal ion distribution in a solidâstate film, the materialâs chemical composition and physical (i.e., electrical, optical, and magnetic) properties can be reversibly reconfigured, in situ, using an applied electric field. The reconfigurability is achieved in a wide range of materials, and can lead to the development of new memory, logic, and multifunctional devices and systems.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141225/1/adma201702770.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141225/2/adma201702770_am.pd
Racial Disparities in Surgical Outcomes after Mastectomy in 223,000 Female Breast Cancer Patients - A Retrospective Cohort Study
BACKGROUND: Breast cancer mortality and treatment differ across racial groups. It remains unclear whether such disparities are also reflected in perioperative outcomes of breast cancer patients undergoing mastectomy.
STUDY DESIGN: We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2008-2021) to identify female patients who underwent mastectomy for oncological purposes. The outcomes were stratified by five racial groups (white, Black/African American, Asian, American Indian/Alaska Native, and Native Hawaiian/Pacific Islander) and included 30-day mortality, reoperation, readmission, surgical and medical complications, and non-home discharge.
RESULTS: The study population included 222,947 patients, 68% (n=151,522) of whom were white, 11% (n=23,987) Black/African American, 5% (n=11,217) Asian, 0.5% (n=1,198) American Indian/Alaska Native, and 0.5% (n=1,018) Native Hawaiian/Pacific Islander. While 136,690 (61%) patients underwent partial mastectomy, 54,490 (24%) and 31,767 (14%) women received simple and radical mastectomy, respectively. Overall, adverse events occurred in 17, 222 (7.7%) patients, the largest portion of which were surgical complications (n=7,246; 3.3%). Multivariable analysis revealed that being of Asian race was protective against perioperative complications (OR=0.71; P<0.001), whereas American Indian/Alaska Native women were most vulnerable to the complication occurrence (OR=1.41; P<0.001). Black/African American patients had a significantly lower risk of medical (OR=0.59; P<0.001) and surgical complications (OR=0.60; P<0.001) after partial and radical mastectomy, respectively, their likelihood of readmission (OR=1.14; P=0.045) following partial mastectomy was significantly increased.
CONCLUSION: We identified American Indian/Alaska Native women as particularly vulnerable to complications following mastectomy. Asian patients experienced the lowest rate of complications in the perioperative period. Our analyses revealed comparable confounder-adjusted outcomes following partial and complete mastectomy between Black and white races. Our findings call for care equalization in the field of breast cancer surgery
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