969 research outputs found
Special Lagrangians, stable bundles and mean curvature flow
We make a conjecture about mean curvature flow of Lagrangian submanifolds of
Calabi-Yau manifolds, expanding on \cite{Th}. We give new results about the
stability condition, and propose a Jordan-H\"older-type decomposition of
(special) Lagrangians. The main results are the uniqueness of special
Lagrangians in hamiltonian deformation classes of Lagrangians, under mild
conditions, and a proof of the conjecture in some cases with symmetry: mean
curvature flow converging to Shapere-Vafa's examples of SLags.Comment: 36 pages, 4 figures. Minor referee's correction
Intramuscular recurrence in a Hepatocellular carcinoma patient with indolent disease course
<p>Abstract</p> <p>Background</p> <p>Hepatocellular carcinoma (HCC) is a common malignancy worldwide and treatment options are depended on the stage of the tumour. In general, the prognosis of HCC patients with extra-hepatic metastasis is poor. The most common sites of extra-hepatic metastasis are the lung, abdominal lymph nodes and bone.</p> <p>Case presentation</p> <p>Here, we reported a 54-year-old man with an indolent clinical course of HCC. He had multiple extra-hepatic recurrences after initial hepatectomy for HCC and was benefited from repeated resections with prolonged survival. Eventually, he developed intramuscular recurrence in the thigh, which was initially mistaken as deep vein thrombosis.</p> <p>Conclusion</p> <p>Selected patients with indolent disease course of HCC may benefit from repeated resections of extra-hepatic metastases with prolonged survival.</p
Special Lagrangian cones with higher genus links
For every odd natural number g=2d+1 we prove the existence of a countably
infinite family of special Lagrangian cones in C^3 over a closed Riemann
surface of genus g, using a geometric PDE gluing method.Comment: 48 page
Numerical Ricci-flat metrics on K3
We develop numerical algorithms for solving the Einstein equation on
Calabi-Yau manifolds at arbitrary values of their complex structure and Kahler
parameters. We show that Kahler geometry can be exploited for significant gains
in computational efficiency. As a proof of principle, we apply our methods to a
one-parameter family of K3 surfaces constructed as blow-ups of the T^4/Z_2
orbifold with many discrete symmetries. High-resolution metrics may be obtained
on a time scale of days using a desktop computer. We compute various geometric
and spectral quantities from our numerical metrics. Using similar resources we
expect our methods to practically extend to Calabi-Yau three-folds with a high
degree of discrete symmetry, although we expect the general three-fold to
remain a challenge due to memory requirements.Comment: 38 pages, 10 figures; program code and animations of figures
downloadable from http://schwinger.harvard.edu/~wiseman/K3/ ; v2 minor
corrections, references adde
Measurements of 12C(→γ,pp) photon asymmetries for Eγ= 200–450 MeV
The 12C (→γ ,pp) reaction has been studied in the photon energy range 200-450 MeV at the Mainz microtron MAMI-C, where linearly polarised photons were energy-tagged using the Glasgow-Mainz Tagged Photon Spectrometer and protons were detected in the Crystal Ball detector. The photon asymmetry Σ has been measured over a wider Eγ range than previous measurements. The strongest asymmetries were found at low missing energies where direct emission of nucleon pairs is expected. Cuts on the difference in azimuthal angles of the two ejected protons increased the magnitude of the observed asymmetries. At low missing energies the Σ data exhibit a strong angular dependence, similar to deuteron photodisintegration
Topological String Amplitudes, Complete Intersection Calabi-Yau Spaces and Threshold Corrections
We present the most complete list of mirror pairs of Calabi-Yau complete
intersections in toric ambient varieties and develop the methods to solve the
topological string and to calculate higher genus amplitudes on these compact
Calabi-Yau spaces. These symplectic invariants are used to remove redundancies
in examples. The construction of the B-model propagators leads to compatibility
conditions, which constrain multi-parameter mirror maps. For K3 fibered
Calabi-Yau spaces without reducible fibers we find closed formulas for all
genus contributions in the fiber direction from the geometry of the fibration.
If the heterotic dual to this geometry is known, the higher genus invariants
can be identified with the degeneracies of BPS states contributing to
gravitational threshold corrections and all genus checks on string duality in
the perturbative regime are accomplished. We find, however, that the BPS
degeneracies do not uniquely fix the non-perturbative completion of the
heterotic string. For these geometries we can write the topological partition
function in terms of the Donaldson-Thomas invariants and we perform a
non-trivial check of S-duality in topological strings. We further investigate
transitions via collapsing D5 del Pezzo surfaces and the occurrence of free Z2
quotients that lead to a new class of heterotic duals.Comment: 117 pages, 1 Postscript figur
PPI-Delayed Diagnosis of Gastrinoma: Oncologic Victim of Pharmacologic Success
Functional neuroendocrine tumors are often low-grade malignant neoplasms that can be cured by surgery if detected early, and such detection may in turn be accelerated by the recognition of neuropeptide hypersecretion syndromes. Uniquely, however, relief of peptic symptoms induced by hypergastrinemia is now available from acid-suppressive drugs such as proton-pump inhibitors (PPIs). Here we describe a clinical case in which time to diagnosis from the onset of peptic symptoms was delayed more than 10 years, in part reflecting symptom masking by continuous prescription of the PPI omeprazole. We propose diagnostic criteria for this under-recognized new clinical syndrome, and recommend that physicians routinely measure serum gastrin levels in persistent cases of PPI-dependent dyspepsia unassociated with H. pylori
Efficacy and Safety of Nivolumab Plus Ipilimumab in Patients With Advanced Hepatocellular Carcinoma Previously Treated With Sorafenib The CheckMate 040 Randomized Clinical Trial
IMPORTANCE Most patients with hepatocellular carcinoma (HCC) are diagnosed with
advanced disease not eligible for potentially curative therapies; therefore, new treatment
options are needed. Combining nivolumab with ipilimumab may improve clinical outcomes
compared with nivolumab monotherapy.
OBJECTIVE To assess efficacy and safety of nivolumab plus ipilimumab in patients with
advanced HCC who were previously treated with sorafenib.
DESIGN, SETTING, AND PARTICIPANTS CheckMate 040 is a multicenter, open-label,
multicohort, phase 1/2 study. In the nivolumab plus ipilimumab cohort, patients were
randomized between January 4 and September 26, 2016. Treatment group information was
blinded after randomization. Median follow-up was 30.7 months. Data cutoff for this analysis
was January 2019. Patients were recruited at 31 centers in 10 countries/territories in Asia,
Europe, and North America. Eligible patients had advanced HCC (with/without hepatitis B or
C) previously treated with sorafenib. A total of 148 patients were randomized (50 to arm A
and 49 each to arms B and C).
INTERVENTIONS Patients were randomized 1:1:1 to either nivolumab 1 mg/kg plus ipilimumab 3
mg/kg, administered every 3 weeks (4 doses), followed by nivolumab 240 mg every 2 weeks
(arm A); nivolumab 3 mg/kg plus ipilimumab 1 mg/kg, administered every 3 weeks (4 doses),
followed by nivolumab 240 mg every 2 weeks (arm B); or nivolumab 3 mg/kg every 2 weeks
plus ipilimumab 1 mg/kg every 6 weeks (arm C).
MAIN OUTCOMES AND MEASURES Coprimary end points were safety, tolerability, and objective
response rate. Duration of response was also measured (investigator assessed with the
Response Evaluation Criteria in Solid Tumors v1.1).
RESULTS Of 148 total participants, 120 were male (81%). Median (IQR) age was 60
(52.5-66.5). At data cutoff (January 2019), the median follow-up was 30.7 months (IQR,
29.9-34.7). Investigator-assessed objective response rate was 32% (95% CI, 20%-47%) in
arm A, 27% (95% CI, 15%-41%) in arm B, and 29% (95% CI, 17%-43%) in arm C. Median
(range) duration of response was not reached (8.3-33.7+) in arm A and was 15.2 months
(4.2-29.9+) in arm B and 21.7 months (2.8-32.7+) in arm C. Any-grade treatment-related
adverse events were reported in 46 of 49 patients (94%) in arm A, 35 of 49 patients (71%) in
arm B, and 38 of 48 patients (79%) in arm C; there was 1 treatment-related death (arm A;
grade 5 pneumonitis).
CONCLUSIONS AND RELEVANCE In this randomized clinical trial, nivolumab plus ipilimumab
had manageable safety, promising objective response rate, and durable responses. The arm A
regimen (4 doses nivolumab 1 mg/kg plus ipilimumab 3 mg/kg every 3 weeks then nivolumab
240 mg every 2 weeks) received accelerated approval in the US based on the results of this
study.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0165887
Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity
Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)
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