Instantons on ALE spaces and orbifold partitions

We consider N=4 theories on ALE spaces of $A_{k-1}$ type. As is well known, their partition functions coincide with $A_{k-1}$ affine characters. We show that these partition functions are equal to the generating functions of some peculiar classes of partitions which we introduce under the name 'orbifold partitions'. These orbifold partitions turn out to be related to the generalized Frobenius partitions introduced by G. E. Andrews some years ago. We relate the orbifold partitions to the blended partitions and interpret explicitly in terms of a free fermion system.Comment: 28 pages, 10 figures; reference adde

H2S adsorption on chromium, chromia, and gold/chromia surfaces: Photoemission studies

The reaction of H2S with chromium, chromia, and Au/chromia films grown on a Pt(111) crystal has been investigated using synchrotron-based high-resolution photoemission spectroscopy. At 300 K, H2S completely decomposes on polycrystalline chromium producing a chemisorbed layer of S that attenuates the Cr 3d valence features. No evidence was found for the formation of CrSx species. The dissociation of H2S on Cr3O4 and Cr2O3 films at room temperature produces a decrease of 0.3–0.8 eV in the work function of the surface and significant binding-energy shifts (0.2–0.6 eV) in the Cr 3p core levels and Cr 3d features in the valence region. The rate of dissociation of H2S increases following the sequence: Cr2O33O4. For chromium, the density of states near the Fermi level is large, and these states offer a better match in energy for electron acceptor or donor interactions with the frontier orbitals of H2S than the valence and conduction bands of the chromium oxides. This leads to a large dissociation probability for H2S on the metal, and a low dissociation probability for the molecule on the oxides. In the case of Cr3O4 and Cr2O3, there is a correlation between the size of the band gap in the oxide and its reactivity toward H2S. The uptake of sulfur by the oxides significantly increases when they are “promoted” with gold. The Au/Cr2O3 surfaces exhibit a unique electronic structure in the valence region and a larger ability to dissociate H2S than polycrystalline Au or pure Cr2O3. The results of ab initio SCF calculations for the adsorption of H2S on AuCr4O6 and AuCr10O15 clusters show a shift of electrons from the gold toward the oxide unit that enhances the strength of the Au(6s)↔H2S(5a1,2b1) bonding interactions and facilitates the decomposition of the molecule. © 1997 American Institute of Physics

Post-treatment three-dimensional voxel-based dosimetry after Yttrium-90 resin microsphere radioembolization in HCC

BACKGROUND: Post-therapy [(90)Y] PET/CT-based dosimetry is currently recommended to validate treatment planning as [(99m)Tc] MAA SPECT/CT is often a poor predictor of subsequent actual [(90)Y] absorbed dose. Treatment planning software became available allowing 3D voxel dosimetry offering tumour-absorbed dose distributions and dose-volume histograms (DVH). We aim to assess dose–response effects in post-therapy [(90)Y] PET/CT dosimetry in SIRT-treated HCC patients for predicting overall and progression-free survival (OS and PFS) and four-month follow-up tumour response (mRECIST). Tumour-absorbed dose and mean percentage of the tumour volume (V) receiving ≥ 100, 150, 200, or 250 Gy and mean minimum absorbed dose (D) delivered to 30%, 50%, 70%, and 90% of tumour volume were calculated from DVH’s. Depending on the mean tumour -absorbed dose, treated lesions were assigned to a < 120 Gy or ≥ 120 Gy group. RESULTS: Thirty patients received 36 SIRT treatments, totalling 43 lesions. Median tumour-absorbed dose was significantly different between the ≥ 120 Gy (n = 28, 207 Gy, IQR 154–311 Gy) and < 120 Gy group (n = 15, 62 Gy, IQR 49–97 Gy, p <0 .01). Disease control (DC) was found more frequently in the ≥ 120 Gy group (79%) compared to < 120 Gy (53%). Mean tumour-absorbed dose optimal cut-off predicting DC was 131 Gy. Tumour control probability was 54% (95% CI 52–54%) for a mean tumour-absorbed dose of 120 Gy and 90% (95% CI 87–92%) for 284 Gy. Only D30 was significantly different between DC and progressive disease (p = 0.04). For the ≥ 120 Gy group, median OS and PFS were longer (median OS 33 months, [range 8–33 months] and median PFS 23 months [range 4–33 months]) than the < 120 Gy group (median OS 17 months, [range 5–33 months] and median PFS 13 months [range 1–33 months]) (p < 0.01 and p = 0.03, respectively). CONCLUSIONS: Higher 3D voxel-based tumour-absorbed dose in patients with HCC is associated with four-month DC and longer OS and PFS. DVHs in [(90)Y] SIRT could play a role in evaluative dosimetry

Novel electronic and magnetic properties of ultrathin chromium oxide films grown on Pt(111)

The growth of epitaxial metal–oxide films on lattice-mismatched metal substrates often results in the formation of unique overlayer structures. In particular, epitaxial chromium oxide films grown on Pt(111) exhibit a p(2×2) symmetry through the first two monolayers of growth which is followed by a (√3×√3)R30° phase that is attributed to the growth of a Cr2O3(0001) overlayer. Ultraviolet photoelectron spectroscopy measurements have been performed on the CrOx/Pt(111) system. The electronic structures of CrO2, Cr2O3, and Cr3O4 were calculated using the linear muffin-tin orbital method in the atomic sphere approximation. Comparison of the photoemission valence band spectra with the calculated density of states indicates that the CrOx initially grows in a cubic spinel Cr3O4 structure. Beyond ∼0.2 monolayers, the metallic behavior of the CrOx overlayer begins a transformation to an insulating state. The measured valence emission for the p(2×2) phase beyond ∼0.2 monolayers is more consistent with either a γ-Cr2O3(111) overlayer or possibly a reconstructed Cr2O3(0001) overlayer. © 1998 American Vacuum Society

Sleep deprivation causes memory deficits by negatively impacting neuronal connectivity in hippocampal area CA1

Brief periods of sleep loss have long-lasting consequences such as impaired memory consolidation. Structural changes in synaptic connectivity have been proposed as a substrate of memory storage. Here, we examine the impact of brief periods of sleep deprivation on dendritic structure. In mice, we find that five hours of sleep deprivation decreases dendritic spine numbers selectively in hippocampal area CA1 and increased activity of the filamentous actin severing protein cofilin. Recovery sleep normalizes these structural alterations. Suppression of cofilin function prevents spine loss, deficits in hippocampal synaptic plasticity, and impairments in long-term memory caused by sleep deprivation. The elevated cofilin activity is caused by cAMP-degrading phosphodiesterase-4A5 (PDE4A5), which hampers cAMP-PKA-LIMK signaling. Attenuating PDE4A5 function prevents changes in cAMP-PKA-LIMK-cofilin signaling and cognitive deficits associated with sleep deprivation. Our work demonstrates the necessity of an intact cAMP-PDE4-PKA-LIMK-cofilin activation-signaling pathway for sleep deprivation-induced memory disruption and reduction in hippocampal spine density

Diagnosis of hepatocellular adenoma in men before onset of diabetes in HNF1A-MODY:Watch out for winkers

Hepatocyte nuclear factor 1A (HNF1A) maturity-onset diabetes of the young (MODY) is a monogenetic, autosomal dominantly inherited form of diabetes. HNF1A-MODY is associated with HNF1A-inactivated hepatocellular adenoma (H-HCA) formation. Hepatocellular adenoma (HCA) are benign liver tumours and related complications are rare but serious: hepatic haemorrhage and malignant transformation. Guidelines recommend resection of all HCA in men and do not take any co-occurring metabolic disorders into account. We report a family with HCA preceding diabetes mellitus. Male index patient presented with numerous, irresectable HCA. After initial diagnostic and aetiologic uncertainty HNF1A germline mutation c.815G>A (p.Arg272His) was confirmed 8 years later. No HCA-related complications occurred. His diabetic mother was diagnosed with HCA after severe hepatic haemorrhage years before. HNF1A-MODY should be considered in (non-)diabetic (male) patients with H-HCA. We advocate liver biopsy and, if necessary, genetic analysis to precede any intervention for HCA in males and screening for HCA in HNF1A-MODY patients

A prospective multicentre trial on survival after Microwave Ablation VErsus Resection for Resectable Colorectal liver metastases (MAVERRIC).

AIM This multi-centre prospective cohort study aimed to investigate non-inferiority in patients' overall survival when treating potentially resectable colorectal cancer liver metastasis (CRLM) with stereotactic microwave ablation (SMWA) as opposed to hepatic resection (HR). METHODS Patients with no more than 5 CRLM no larger than 30 mm, deemed eligible for both SMWA and hepatic resection at the local multidisciplinary team meetings, were deliberately treated with SMWA (study group). The contemporary control group consisted of patients with no more than 5 CRLM, none larger than 30 mm, treated with HR, extracted from a prospectively maintained nationwide Swedish database. After propensity-score matching, 3-year overall survival (OS) was compared as the primary outcome using Kaplan-Meier and Cox regression analyses. RESULTS All patients in the study group (n = 98) were matched to 158 patients from the control group (mean standardised difference in baseline covariates = 0.077). OS rates at 3 years were 78% (Confidence interval [CI] 68-85%) after SMWA versus 76% (CI 69-82%) after HR (stratified Log-rank test p = 0.861). Estimated 5-year OS rates were 56% (CI 45-66%) versus 58% (CI 50-66%). The adjusted hazard ratio for treatment type was 1.020 (CI 0.689-1.510). Overall and major complications were lower after SMWA (percentage decrease 67% and 80%, p < 0.01). Hepatic retreatments were more frequent after SMWA (percentage increase 78%, p < 0.01). CONCLUSION SMWA is a valid curative-intent treatment alternative to surgical resection for small resectable CRLM. It represents an attractive option in terms of treatment-related morbidity with potentially wider options regarding hepatic retreatments over the future course of disease

Behavior and complications of hepatocellular adenoma during pregnancy and puerperium:a retrospective study and systematic review

BACKGROUND: Hepatocellular adenomas (HCA) are benign liver tumors at risk of hemorrhage. The influence of pregnancy on HCA growth and potential bleeding remains unclear. This study investigates HCA-associated behavior and bleeding complications during or shortly after pregnancy. METHODS: (I) Single center retrospective cohort study of HCA during and after pregnancy (II) Systematic literature review. RESULTS: The retrospective study included 11 patients, of which 4 with HCA ≥5 cm. In only two patients HCA showed growth during pregnancy. In this local cohort, no HCA-related hemorrhages occurred during median follow-up of 34 months (interquartile range 19-58 months). The systematic review yielded 33 studies, totaling 90 patients with 99 pregnancies. Of 73 pregnancies without prior HCA-related intervention, 39 HCA remained stable (53.4%), 11 regressed (15.1%), and 23 (31.5%) progressed. Fifteen HCA-related hemorrhages occurred in HCA measuring 6.5-17.0 cm. Eight patients experienced bleeding during pregnancy, two during labor and five postpartum. CONCLUSION: Although hemorrhage of HCA during or shortly after pregnancy is rare and only reported in HCA ≥6.5 cm, it can be fatal. Pregnancy in women with HCA, regardless of size, warrant a close surveillance strategy. Observational studies on behavior and management of HCA ≥5 cm during and immediately after pregnancy are needed

Kidney Infarction in Patients With COVID-19

Coronavirus disease 2019 (COVID-19) is a contagious life-threatening infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Recent findings indicate an increased risk for acute kidney injury during COVID-19 infection. The pathophysiologic mechanisms leading to acute kidney injury in COVID-19 infection are unclear but may include direct cytopathic effects of the virus on kidney tubular and endothelial cells, indirect damage caused by virus-induced cytokine release, and kidney hypoperfusion due to a restrictive fluid strategy. In this report of 2 cases, we propose an additional pathophysiologic mechanism. We describe 2 cases in which patients with COVID-19 infection developed a decrease in kidney function due to kidney infarction. These patients did not have atrial fibrillation. One of these patients was treated with therapeutic doses of low-molecular-weight heparin, after which no further deterioration in kidney function was observed. Our findings implicate that the differential diagnosis of acute kidney injury in COVID-19–infected patients should include kidney infarction, which may have important preventive and therapeutic implications