Constraints on the superconducting order parameter in Sr2RuO4 from oxygen-17 nuclear magnetic resonance.

Phases of matter are usually identified through spontaneous symmetry breaking, especially regarding unconventional superconductivity and the interactions from which it originates. In that context, the superconducting state of the quasi-two-dimensional and strongly correlated perovskite Sr2RuO4 is considered to be the only solid-state analogue to the superfluid 3He-A phase1,2, with an odd-parity order parameter that is unidirectional in spin space for all electron momenta and breaks time-reversal symmetry. This characterization was recently called into question by a search for an expected 'split' transition in a Sr2RuO4 crystal under in-plane uniaxial pressure, which failed to find any such evidence; instead, a dramatic rise and a peak in a single-transition temperature were observed3,4. Here we use nuclear magnetic resonance (NMR) spectroscopy of oxygen-17, which is directly sensitive to the order parameter via hyperfine coupling to the electronic spin degrees of freedom, to probe the nature of superconductivity in Sr2RuO4 and its evolution under strain. A reduction of the Knight shift is observed for all strain values and at temperatures below the critical temperature, consistent with a drop in spin polarization in the superconducting state. In unstrained samples, our results contradict a body of previous NMR work reporting no change in the Knight shift5 and the most prevalent theoretical interpretation of the order parameter as a chiral p-wave state. Sr2RuO4 is an extremely clean layered perovskite and its superconductivity emerges from a strongly correlated Fermi liquid, and our work imposes tight constraints on the order parameter symmetry of this archetypal system.

Thermoelectric performance of a metastable thin-film Heusler alloy.

Thermoelectric materials transform a thermal gradient into electricity. The efficiency of this process relies on three material-dependent parameters: the Seebeck coefficient, the electrical resistivity and the thermal conductivity, summarized in the thermoelectric figure of merit. A large figure of merit is beneficial for potential applications such as thermoelectric generators. Here we report the thermal and electronic properties of thin-film Heusler alloys based on Fe2V0.8W0.2Al prepared by magnetron sputtering. Density functional theory calculations suggest that the thin films are metastable states, and measurements of the power factor-the ratio of the Seebeck coefficient squared divided by the electrical resistivity-suggest a high intrinsic figure of merit for these thin films. This may arise from a large differential density of states at the Fermi level and a Weyl-like electron dispersion close to the Fermi level, which indicates a high mobility of charge carriers owing to linear crossing in the electronic bands.

Factors associated with successful median arcuate ligament release in an international, multi-institutional cohort.

OBJECTIVE: Prior research on median arcuate ligament syndrome has been limited to institutional case series, making the optimal approach to median arcuate ligament release (MALR) and resulting outcomes unclear. In the present study, we compared the outcomes of different approaches to MALR and determined the predictors of long-term treatment failure. METHODS: The Vascular Low Frequency Disease Consortium is an international, multi-institutional research consortium. Data on open, laparoscopic, and robotic MALR performed from 2000 to 2020 were gathered. The primary outcome was treatment failure, defined as no improvement in median arcuate ligament syndrome symptoms after MALR or symptom recurrence between MALR and the last clinical follow-up. RESULTS: For 516 patients treated at 24 institutions, open, laparoscopic, and robotic MALR had been performed in 227 (44.0%), 235 (45.5%), and 54 (10.5%) patients, respectively. Perioperative complications (ileus, cardiac, and wound complications; readmissions; unplanned procedures) occurred in 19.2% (open, 30.0%; laparoscopic, 8.9%; robotic, 18.5%; P < .001). The median follow-up was 1.59 years (interquartile range, 0.38-4.35 years). For the 488 patients with follow-up data available, 287 (58.8%) had had full relief, 119 (24.4%) had had partial relief, and 82 (16.8%) had derived no benefit from MALR. The 1- and 3-year freedom from treatment failure for the overall cohort was 63.8% (95% confidence interval [CI], 59.0%-68.3%) and 51.9% (95% CI, 46.1%-57.3%), respectively. The factors associated with an increased hazard of treatment failure on multivariable analysis included robotic MALR (hazard ratio [HR], 1.73; 95% CI, 1.16-2.59; P = .007), a history of gastroparesis (HR, 1.83; 95% CI, 1.09-3.09; P = .023), abdominal cancer (HR, 10.3; 95% CI, 3.06-34.6; P < .001), dysphagia and/or odynophagia (HR, 2.44; 95% CI, 1.27-4.69; P = .008), no relief from a celiac plexus block (HR, 2.18; 95% CI, 1.00-4.72; P = .049), and an increasing number of preoperative pain locations (HR, 1.12 per location; 95% CI, 1.00-1.25; P = .042). The factors associated with a lower hazard included increasing age (HR, 0.99 per increasing year; 95% CI, 0.98-1.0; P = .012) and an increasing number of preoperative diagnostic gastrointestinal studies (HR, 0.84 per study; 95% CI, 0.74-0.96; P = .012) Open and laparoscopic MALR resulted in similar long-term freedom from treatment failure. No radiographic parameters were associated with differences in treatment failure. CONCLUSIONS: No difference was found in long-term failure after open vs laparoscopic MALR; however, open release was associated with higher perioperative morbidity. These results support the use of a preoperative celiac plexus block to aid in patient selection. Operative candidates for MALR should be counseled regarding the factors associated with treatment failure and the relatively high overall rate of treatment failure.

Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5.

Electronic nematic materials are characterized by a lowered symmetry of the electronic system compared to the underlying lattice, in analogy to the directional alignment without translational order in nematic liquid crystals. Such nematic phases appear in the copper- and iron-based high-temperature superconductors, and their role in establishing superconductivity remains an open question. Nematicity may take an active part, cooperating or competing with superconductivity, or may appear accidentally in such systems. Here we present experimental evidence for a phase of fluctuating nematic character in a heavy-fermion superconductor, CeRhIn5 (ref. 5). We observe a magnetic-field-induced state in the vicinity of a field-tuned antiferromagnetic quantum critical point at Hc ≈ 50 tesla. This phase appears above an out-of-plane critical field H* ≈ 28 tesla and is characterized by a substantial in-plane resistivity anisotropy in the presence of a small in-plane field component. The in-plane symmetry breaking has little apparent connection to the underlying lattice, as evidenced by the small magnitude of the magnetostriction anomaly at H*. Furthermore, no anomalies appear in the magnetic torque, suggesting the absence of metamagnetism in this field range. The appearance of nematic behaviour in a prototypical heavy-fermion superconductor highlights the interrelation of nematicity and unconventional superconductivity, suggesting nematicity to be common among correlated materials.

Utility of Hook Sign in the Diagnosis of Median Arcuate Ligament Syndrome.

BACKGROUND: Median arcuate ligament syndrome (MALS) is a clinical syndrome caused by compression of the celiac artery by the median arcuate ligament that often manifests with nonspecific abdominal pain. Identification of this syndrome is often dependent on imaging of compression and upward bending of the celiac artery by lateral computed tomography angiography, the so-called "hook sign." The purpose of this study was to assess the relationship of radiologic characteristics of the celiac artery to clinically relevant MALS. METHODS: An institutional review board-approved retrospective chart review from 2,000 to 2,021 of 293 patients at a tertiary academic center diagnosed with celiac artery compression (CAC) was performed. Patient demographics and symptoms of 69 patients who were diagnosed with symptomatic MALS were compared to 224 patients without MALS (but with CAC) per electronic medical record review. Computed tomography angiography images were reviewed and the fold angle (FA) was measured. The presence of a hook sign (defined as a visual FA < 135°), as well as stenosis (defined as >50% of luminal narrowing on imaging) were recorded. Wilcoxon rank-sum test and Chi-squared test were used for comparative analysis. Logistic model was run to relate the presence of MALS with comorbidities and radiographic findings. RESULTS: Imaging was available in 59 patients (25 males, 34 females) and 157 patients (60 males, 97 females) with and without MALS, respectively. Patients with MALS were more likely to have a more severe FA (120.7 ± 33.6 vs. 134.8 ± 27.9, P = 0.002). Males with MALS were also more likely to have a more severe FA compared with males without MALS (111.1 ± 33.7 vs. 130.4 ± 30.4, P = 0.015). In patients with body mass index (BMI) >25, MALS patients also had narrower FA compared with patients without MALS (112.6 ± 30.5 vs. 131.7 ± 30.3, P = 0.001). The FA was negatively correlated with BMI in patients with CAC. The hook sign and stenosis were associated with diagnosis of MALS (59.3% vs. 28.7%, P < 0.001, and 75.7% vs. 45.2%, P < 0.001, respectively). In logistic regression, pain, stenosis, and a narrow FA were statistically significant predictors of the presence of MALS. CONCLUSIONS: The upward deflection of the celiac artery in patients with MALS is more severe compared with patients without MALS. Consistent with prior literature, this bending of the celiac artery is negatively correlated with BMI in patients with and without MALS. When demographic variables and comorbidities are considered, a narrow FA is a statistically significant predictor of MALS. Regardless of MALS diagnosis, a hook sign was associated with narrower FA. While demographics and imaging findings may inform MALS diagnosis, clinicians should not rely on a visual assessment of a hook sign but should quantitatively measure the anatomic bending angle of the celiac artery to assist with the diagnosis and understand the outcomes.

Picture recognition of food by sloth bears (Melursus ursinus).

Pictures are often used in cognitive research to represent objects and many species have demonstrated the ability to recognize two-dimensional pictures as representations of their three-dimensional counterparts. However, for ursids picture recognition has been reported in only one study of a single 11-year-old female American black bear (Johnson-Ulrich et al. 2016). We tested the picture recognition abilities of an additional species, the sloth bear. After a food preference test by which the bears' food options were ranked and categorized as high-, mid-, and low-preference items, we tested a sub-adult male and an adult female sloth bear by presenting two pictures of food in each testing trial-a high-preference food and a low-preference food. Both bears met the criterion by choosing the pictures of their preferred foods in at least 80% of the trials in three consecutive testing sessions. We then presented never-before-used pictures of high-preference versus low-preference food items and they again met our criterion.

A real world analysis of recurrence risk factors for early colorectal cancer T1 treated with standard endoscopic resection.

BACKGROUND AND STUDY AIM: Currently, endoscopic resection of early colorectal cancer defined as carcinoma with limited invasion of the mucosa (Tis) and submucosa (T1) is possible. However, lymph node spreading increases to 16.2% of cases when tumor invades the submucosa. We analyzed the previously identified factors for lymph node dissemination and recurrence, in our population. PATIENTS AND METHODS: We analyzed retrospectively all patients with T1 tumors, treated at our center with endoscopic resection and some with additional surgery between January 2006 and January 2018. Statistical analysis was performed using IBM SPSS Statistics 25.0. RESULTS: One hundred fifty-nine patients were treated with endoscopic resection, 56.6% with additional surgery. The mean age was 68.74 years and 69. 9% were male. All patients who underwent additional surgery presented negative margins and 8.8% presented positive lymph nodes. In a mean follow-up of 23.36 months, 13 patients had relapsed. The risk of relapse did not differ between patients treated with additional surgery from those who only underwent endoscopic resection (p = 0.506). On the other hand, lymph node dissemination (p = 0.007) and a positive endoscopic margin (p = 0.01) were independent risk factors for relapse. There was a positive association between lymph node dissemination and lymphatic (p = 0.07), vascular (p = 0.007), and perineural (p = 0.001) invasion and also with degree of histological differentiation (p = 0.001). CONCLUSION: In our study, lymphatic, vascular, and perineural invasion and also the degree of histological differentiation were associated with lymph node dissemination. However, the only independent risk factors for long-term recurrence were a positive margin and lymph node dissemination.

Competing magnetic orders in the superconducting state of heavy-fermion CeRhIn5.

Applied pressure drives the heavy-fermion antiferromagnet CeRhIn5 toward a quantum critical point that becomes hidden by a dome of unconventional superconductivity. Magnetic fields suppress this superconducting dome, unveiling the quantum phase transition of local character. Here, we show that [Formula: see text] magnetic substitution at the Ce site in CeRhIn5, either by Nd or Gd, induces a zero-field magnetic instability inside the superconducting state. This magnetic state not only should have a different ordering vector than the high-field local-moment magnetic state, but it also competes with the latter, suggesting that a spin-density-wave phase is stabilized in zero field by Nd and Gd impurities, similarly to the case of Ce0.95Nd0.05CoIn5 Supported by model calculations, we attribute this spin-density wave instability to a magnetic-impurity-driven condensation of the spin excitons that form inside the unconventional superconducting state.

Enhanced Hybridization Sets the Stage for Electronic Nematicity in CeRhIn_{5}.

High magnetic fields induce a pronounced in-plane electronic anisotropy in the tetragonal antiferromagnetic metal CeRhIn_{5} at H^{*}≳30 T for fields ≃20° off the c axis. Here we investigate the response of the underlying crystal lattice in magnetic fields to 45 T via high-resolution dilatometry. At low fields, a finite magnetic field component in the tetragonal ab plane explicitly breaks the tetragonal (C_{4}) symmetry of the lattice revealing a finite nematic susceptibility. A modest a-axis expansion at H^{*} hence marks the crossover to a fluctuating nematic phase with large nematic susceptibility. Magnetostriction quantum oscillations confirm a Fermi surface change at H^{*} with the emergence of new orbits. By analyzing the field-induced change in the crystal-field ground state, we conclude that the in-plane Ce 4f hybridization is enhanced at H^{*}, in agreement with the in-plane lattice expansion. We argue that the nematic behavior observed in this prototypical heavy-fermion material is of electronic origin, and is driven by the hybridization between 4f and conduction electrons which carries the f-electron anisotropy to the Fermi surface.

Higher Inpatient Mortality for Women after Intervention for Lifestyle Limiting Claudication.

BACKGROUND: Sex-related differences in outcomes have been identified in patients with peripheral artery disease (PAD). We hypothesized that women with PAD would have equivalent inpatient mortality with men after vascular intervention. METHODS: Patients with a primary diagnosis of critical limb ischemia (CLI) or lifestyle-limiting claudication (LLC) receiving endovascular (EV) or open surgical repair from 2003-2012 were identified from the Nationwide Inpatient Sample. Demographics, comorbidities, and inpatient mortality were analyzed by chi-squared tests of independence and independent-samples t-tests. Logistic regression analysis was performed to identify predictors of inpatient mortality. SPSS 24 software was used with P < 0.05 considered statistically significant. RESULTS: We identified 139,435 (59,432 women and 80,003 men) individuals meeting the aforementioned criteria. Women were older than men (71.5 years vs. 68.2, P < 0.001). There were no differences in racial distribution but women had lower rates of diabetes (38.6% vs. 39.7%, P < 0.001), chronic obstructive pulmonary disease (17.9% vs. 19.5%, P < 0.001), and coronary artery disease (38.6% vs. 47.4%, P < 0.001), while having a higher rate of hypertension (60.0% vs. 56.1%, P < 0.001). There was no sex-related difference in the rate of chronic renal failure. Women had higher inpatient mortality than men after vascular intervention (1.3% vs. 1.1%, P < 0.001). When stratified by surgical technique, women also had higher inpatient mortality after EV repair (1.0% vs. 0.8%, P < 0.05) and open repair (1.9% vs 1.3%, P < 0.001). When separated by admitting diagnosis, women with CLI had higher inpatient mortality than men after open surgery (2.3% vs. 1.9%, P < 0.05) but not after EV intervention. Women with LLC had higher inpatient mortality after both open (0.6% vs. 0.3%, P < 0.05) and EV surgery (0.3% vs. 0.1%, P < 0.05). Regression analysis revealed female sex as an independent predictor of inpatient mortality in patients with LLC (OR, 1.74; 95% CI 1.30-2.32, P < 0.001) but not CLI. CONCLUSIONS: Women had higher inpatient mortality than men after vascular intervention for PAD. Women were also older and more likely to have EV intervention than men. Subgroup analysis suggests that these sex-related differences in inpatient mortality are more pronounced in patients with LLC than with CLI. Furthermore, regression analysis shows that sex is a significant predictor for patients diagnosed with LLC but not with CLI. Treatment guidelines should include consideration of sex in their indications for revascularization, particularly for patients diagnosed with LLC.

Improved mortality in treatment of patients with endovascular interventions for chronic mesenteric ischemia.

OBJECTIVE: Chronic mesenteric ischemia (CMI) continues to be a devastating diagnosis. There is a national trend toward increased use of endovascular procedures with improved survival for the treatment of these patients. Our aim was to evaluate whether this trend has changed CMI patients' length of hospitalization and health care cost. METHODS: We identified all patients admitted for CMI from the National Inpatient Sample (NIS) from 2000 to 2014. Our primary end points included length of hospital stay (LOS) and cost of hospitalization (COH). Our secondary end points included mortality assessment of the CMI hospitalization. RESULTS: There were 15,475 patients admitted for CMI. The mean age of patients was 71 years, and 4022 (26.0%) were male. There were 10,920 (70.6%) patients treated endovascularly (ENDO) and 4555 (29.4%) patients treated in an open fashion (OPEN). Although a higher proportion of patients in the ENDO (43.3%) group vs OPEN (33.1%) had a Charlson Comorbidity Index score of ≥2 (P < .0001), they had a lower mortality rate (2.4% vs 8.7%; P < .0001), lower mean LOS (6.3 vs 14.0 days; P < .0001), and lower COH ($21,686 vs $42,974; P < .0001). After adjusting for clinical and hospital factors, OPEN continued to demonstrate higher mortality than ENDO (odds ratio, 7.2; 95% confidence interval, 4.9-10.6; P < .0001), longer LOS (mean, +9.7 days; P < .0001), and higher COH (mean, +$25,834; P < .0001). CONCLUSIONS: The rate of ENDO continues to rise nationally in the treatment of CMI patients. After adjusting for clinical and hospital factors, patients in the ENDO group tend to have lower in-hospital mortality of 2.4% and lower LOS by 10 days, and they incur a cost saving of >$25,000 compared with patients in the OPEN group. ENDO should be considered first line of therapy for patients with CMI.

Endovascular interventions decrease length of hospitalization and are cost-effective in acute mesenteric ischemia.

OBJECTIVE: Acute mesenteric ischemia (AMI) continues to be one of the most devastating diagnoses requiring emergent vascular intervention. There is a national trend toward increased use of endovascular procedures, with improved survival for the treatment of these patients. Our aim was to evaluate whether this trend has changed the treatment of AMI and the subsequent impact on length of hospitalization and hospitalization costs. METHODS: We identified all patients admitted for AMI from the National Inpatient Sample from 2004 to 2014 who received open surgical revascularization (OPEN) or an endovascular intervention (ENDO). Primary end points included length of hospital stay and cost of hospitalization. Our secondary end points included acute kidney injury (AKI), in-hospital mortality, and routine discharge. RESULTS: Among 10,381 discharges identified in the data set, 3833 (37%; 97.5% confidence interval [CI], 35%-39%) were male patients with a mean age of 69 years (range, 18-98 years); 4543 (44%; 97.5% CI, 41%-47%) patients were treated ENDO, and 5839 (56%; 97.5% CI, 53%-59%) patients were treated OPEN. Although a higher proportion of patients in the ENDO group (28%; 97.5% CI, 24%-31%) vs the OPEN group (14%; 97.5% CI, 11%-16%) had a moderate to severe Charlson Comorbidity Index (P < .0001), ENDO was associated with a lower mortality rate (12.3% [97.5% CI, 9.8%-14.8%] vs 33.1% [97.5% CI, 29.9%-36.2%]; P < .0001) and a lower mean hospitalization cost ($41,615 [97.5% CI, $38,663-$44,567] vs $60,286 [97.5% CI, $56,736-$63,836]; P < .0001). After propensity-adjusted logistic regression analysis, OPEN retained a significant association with higher mortality than ENDO (odds ratio, 3.0; 97.5% CI, 2.2-4.1) and with higher costs (mean, $9196; 97.5% CI, $3797-$14,595). Patients in the OPEN group had higher risk for AKI (P < .0001) and discharge to a skilled nursing facility (P < .0001) rather than home. CONCLUSIONS: Although the rate of ENDO continues to rise nationally, it still has not surpassed OPEN revascularization in the face of AMI. Patients treated endovascularly demonstrated one-third the rate of in-hospital mortality (odds ratio, 3.0; 97.5% CI, 2.2-4.1), an increased hazard ratio for discharge alive (hazard ratio, 2.27; 97.5% CI, 2.00-2.58), and a cost saving of $9196 (97.5% CI, $3797-$14,595) per hospitalization. Furthermore, they were less likely to develop AKI and to be discharged home after hospitalization.

From Ising Resonant Fluctuations to Static Uniaxial Order in Antiferromagnetic and Weakly Superconducting CeCo(In_{1-x}Hg_{x})_{5}(x=0.01).

CeCo(In_{0.990}Hg_{0.010})_{5} is a charge doped variant of the d-wave CoCoIn_{5} superconductor with coexistent antiferromagnetic and superconducting transitions occurring at T_{N}=3.4 and T_{c}=1.4 K, respectively. We use neutron diffraction and spectroscopy to show that the magnetic resonant fluctuations present in the parent superconducting phase are replaced by collinear c-axis magnetic order with three-dimensional Ising critical fluctuations. No low-energy transverse spin fluctuations are observable in this doping-induced antiferromagnetic phase and the dynamic resonant spectral weight predominately shifts to the elastic channel. Static (τ>0.2 ns) collinear Ising order is proximate to superconductivity in CeCoIn_{5} and is stabilized through hole doping with Hg.

Increased mortality in octogenarians treated for lifestyle limiting claudication.

OBJECTIVE: Treatment for lifestyle limiting claudication (LLC) that is due to infra-inguinal peripheral artery disease relies on either bypass, angioplasty, and/or stenting. Given the enthusiasm and shift toward more endovascular therapy for treatment of LLC, we sought to analyze whether octogenarians benefit from infra-inguinal interventions in the same manner as their younger counterparts. METHODS: We identified all patients admitted for elective treatment of LLC from the Nationwide Inpatient Sample from 2003 to 2012, who received open surgical or endovascular intervention for infra-inguinal peripheral arterial disease. These patients were divided into two groups including those between the ages 60-80 years (younger cohort) and those older than 80 years (octogenarians). Primary end-points included morbidity and mortality and the secondary end-points were length of hospital stay (LOS) and disposition after dismissal. RESULTS: Among 59,323 discharges identified in the dataset, 34,658 (58%) were males. There were 50,323 (85%) patients in the younger cohort and 9,000 (15%) octogenarians. The mean age was 69.9 ± 5.7 years and 84.2 ± 3.0 years for the younger cohort and octogenarians, respectively. The mean Charlson comorbidity index (CCI) was higher in our younger cohort (2.1 ± 1.1, P < 0.001). Octogenarians mainly treated with open surgery prior to 2004 are now treated endovascularly and this trend has remained stable. The younger cohort's treatment modality has fluctuated through the study period and most recently is treated mainly with open surgery. The rate of acute kidney injury, exacerbation of congestive heart failure and mortality was higher in octogenarians (P < 0.001). The rate of infectious wound complications was higher in the younger cohort (P < 0.05). Octogenarians have longer LOS and are dismissed in higher percentage to a skilled nursing facility (P < 0.001). On binary logistic regression analysis, age over 80 years, female sex, higher CCI and having an open as opposed to an endovascular procedure are independent predictors of in-hospital mortality. CONCLUSIONS: Although endovascular techniques seem to dominate the care for octogenarians with LLC, the overall morbidity and mortality rates are significantly higher in this patient population. Other options such as medical management and/or supervised exercise therapy should be explored in this patient group.

Transanal endoscopic surgery is effective and safe after endoscopic polypectomy of potentially malignant rectal polyps with questionable margins.

AIM: To determine the percentage of residual lesion observed in the pathology study of transanal endoscopic surgery (TEM) specimens after endoscopic polypectomy of malignant rectal polyps with questionable margins, and the need for further surgery. Secondary aims: to determine the morbidity and mortality associated with this procedure and to identify the percentage of recurrence after excision by TEM. METHODS: Observational study with prospective data collection of all patients undergoing TEM after endoscopic polypectomy for malignant rectal polyps or non-invasive high-grade neoplasia, from January 2004 to December 2016. An en bloc full-thickness wall excision of the scar was performed. Variables recorded: histology of TEM specimen, 30-day morbidity and mortality according to the Clavien-Dindo classification, need for salvage surgery and recurrence. RESULTS: Fifty out of 690 patients undergoing TEM during the study period (36 adenocarcinomas, five non-invasive high-grade neoplasias and 9 neuroendocrine tumors) were included. Post-surgery histology showed residual lesion in 21 (42%) patients: 7 neuroendocrine tumors, 10 adenomas and 4 adenocarcinomas (two pT1, one pT2 and one pT3). The pT2 and pT3 patients (4%) underwent salvage surgery. No recurrence was observed, and mean follow-up was 29.1Â ± 21.6 months. The 30-day morbidity rate was 14%, but 4/7 with Clavien-Dindo grade I. CONCLUSIONS: After endoscopic polypectomy of malignant rectal polyps with questionable margins, the presence of residual lesion in the pathology study of transanal resection specimens is high. TEM with full-thickness resection of these lesions is an appropriate treatment, allowing disease control and achieving minimal morbidity.

Regulation of Yes-Associated Protein by Laminar Flow.

BACKGROUND: The cells lining the endothelium of blood vessels are recognized as playing critical roles in vascular health and disease. The mechanisms that regulate endothelial cells (ECs) proliferation and release of mediators remain poorly understood but represent a potential source of disease modulation. Actin-cytoskeleton remodeling and cell shape have been suggested as key regulators of phosphorylation of yes-associated protein (YAP) which controls cellular growth and proliferation. Because different types of flow have been shown to affect cell shape and cytoskeleton differently, we hypothesized that the level of phosphorylated yes-associated protein (pYAP; serine 127) decreases in EC exposed to pulsatile uniform flow or steady laminar flow, whereas exposure to pulsatile disturbed flow causes an increase or no change. METHODS: Human umbilical vein endothelial cells (HUVECs) were exposed to pulsatile uniform flow, pulsatile disturbed flow, or steady laminar flow and analyzed by immunoblotting. RESULTS: Exposure of HUVECs to steady laminar flow caused a significant decrease in the levels of pYAP (69.7 + 2.6%, P < 0.05), whereas total YAP levels remained nearly unchanged. Conversely, exposure to either pulsatile uniform or disturbed flow caused a significant decrease in the levels of both pYAP (63.2 + 10.9% and 69.8 + 11.9%, respectively; P < 0.05) and total YAP (57.1 + 17.8% and 58.4 + 16.3%, respectively; P < 0.05). Addition of MG132, a ubiquitin-proteasome system inhibitor, failed to significantly inhibit the decrease in the levels of total YAP in HUVECs exposed to either pulsatile uniform or disturbed flow. CONCLUSIONS: Flow causes a decrease in pYAP. The observed decrease in total YAP levels with pulsatile flow is due to degradation via a proteasome-independent mechanism. This may be a potential target for intervention for disease states such as atherosclerosis and intimal hyperplasia.

Acute Limb Ischemia in an 8-Year-Old Patient: A Case Report.

We report the case of an 8-year-old patient with a history of nephrotic syndrome, who presented to the emergency department with right foot pain. The patient's mother described intermittent pain that woke her son from sleep and was accompanied by the foot turning purple and becoming cold to touch. Physical examination revealed capillary refill of over 10 seconds in the right and less than 2 seconds in the left foot. Ankle-brachial indices (ABIs) were 0.0 on the right and 0.96 on the left. The patient was admitted and started on therapeutic intravenous heparin. After consultation with his parents, right lower extremity angiography and thrombolysis was performed over 2 days. He subsequently underwent fasciotomy and amputation of the tip of all 5 toes. Eighteen months later, there is no leg length discrepancy, he is walking with foot inserts and has normal ABIs bilaterally.

Avoided valence transition in a plutonium superconductor.

The d and f electrons in correlated metals are often neither fully localized around their host nuclei nor fully itinerant. This localized/itinerant duality underlies the correlated electronic states of the high-Tc cuprate superconductors and the heavy-fermion intermetallics and is nowhere more apparent than in the 5f valence electrons of plutonium. Here, we report the full set of symmetry-resolved elastic moduli of PuCoGa5--the highest Tc superconductor of the heavy fermions (Tc = 18.5 K)--and find that the bulk modulus softens anomalously over a wide range in temperature above Tc. The elastic symmetry channel in which this softening occurs is characteristic of a valence instability--therefore, we identify the elastic softening with fluctuations of the plutonium 5f mixed-valence state. These valence fluctuations disappear when the superconducting gap opens at Tc, suggesting that electrons near the Fermi surface play an essential role in the mixed-valence physics of this system and that PuCoGa5 avoids a valence transition by entering the superconducting state. The lack of magnetism in PuCoGa5 has made it difficult to reconcile with most other heavy-fermion superconductors, where superconductivity is generally believed to be mediated by magnetic fluctuations. Our observations suggest that valence fluctuations play a critical role in the unusually high Tc of PuCoGa5.

Fermi surface reconstruction and multiple quantum phase transitions in the antiferromagnet CeRhIn5.

Conventional, thermally driven continuous phase transitions are described by universal critical behavior that is independent of the specific microscopic details of a material. However, many current studies focus on materials that exhibit quantum-driven continuous phase transitions (quantum critical points, or QCPs) at absolute zero temperature. The classification of such QCPs and the question of whether they show universal behavior remain open issues. Here we report measurements of heat capacity and de Haas-van Alphen (dHvA) oscillations at low temperatures across a field-induced antiferromagnetic QCP (Bc0 ≈ 50 T) in the heavy-fermion metal CeRhIn5. A sharp, magnetic-field-induced change in Fermi surface is detected both in the dHvA effect and Hall resistivity at B0* ≈ 30 T, well inside the antiferromagnetic phase. Comparisons with band-structure calculations and properties of isostructural CeCoIn5 suggest that the Fermi-surface change at B0* is associated with a localized-to-itinerant transition of the Ce-4f electrons in CeRhIn5. Taken in conjunction with pressure experiments, our results demonstrate that at least two distinct classes of QCP are observable in CeRhIn5, a significant step toward the derivation of a universal phase diagram for QCPs.

Explantation of infected aortic aneurysm and endograft with ascending aorta to mesenteric bypass for mesenteric ischemia.

A 65-year-old man presented with an infected perivisceral aortic aneurysm after previous treatment of an abdominal aortic aneurysm with an endograft. On presentation, he was septic and had occlusion of the celiac, superior mesenteric, inferior mesenteric, and bilateral renal arteries. He underwent a three-stage procedure: first, axillobifemoral bypass; then resection of the thoracoabdominal aorta; and finally bypass from the ascending aorta to the celiac and superior mesenteric arteries with a rifampin-soaked Gelsoft graft (Vascutek, Renfrewshire, Scotland). The abdominal pain resolved, and the patient remains symptom free 10 months postoperatively. This rare surgical revascularization technique offered a nontraditional solution to a difficult surgical issue.