557 research outputs found
Role of Nanoclays in Carbon stabilization in Andisols and Cambisols
Greenhouse gas (GHG) emissions and their consequent effect on global warming are an issue of global environmental concern. Increased carbon (C) stabilization and sequestration in soil organic matter (SOM) is one of the ways to mitigate these emissions. Here we evaluated the role of nanoclays isolated from soil on C stabilization in both a C rich Andisols and C depleted Cambisols. Nanoclays were analyzed for size and morphology by transmission electron microscopy, for elemental composition and molecular composition using pyrolysis-GC/MS. Moreover, nanoclays were treated with H2O2 to isolate stable SOM associated with them. Our result showed better nanoclay extraction efficiency and higher nanoclay yield for Cambisol compared to Andisols, probably related to their low organic matter content. Nanoclay fractions from both soils were different in size, morphology, surface reactivity and SOM content. Nanoclays in Andisols sequester around 5-times more C than Cambisols, and stabilized 6 to 8-times more C than Cambisols nanoclay after SOM chemical oxidation. Isoelectric points and surface charge of nanoclays extracted from the two soils was very different. However, the chemical reactivity of the nanoclay SOM was similar, illustrating their importance for C sequestration. Generally, the precise C stabilization mechanisms of both soils may be different, with nanoscale aggregation being more important in Andisols. We can conclude that independent of the soil type and mineralogy the nanoclay fraction may play an important role in C sequestration and stabilization in soil-plant systems
Laplace transformations of hydrodynamic type systems in Riemann invariants: periodic sequences
The conserved densities of hydrodynamic type system in Riemann invariants
satisfy a system of linear second order partial differential equations. For
linear systems of this type Darboux introduced Laplace transformations,
generalising the classical transformations in the scalar case. It is
demonstrated that Laplace transformations can be pulled back to the
transformations of the corresponding hydrodynamic type systems. We discuss
periodic Laplace sequences of with the emphasize on the simplest nontrivial
case of period 2. For 3-component systems in Riemann invariants a complete
discription of closed quadruples is proposed. They turn to be related to a
special quadratic reduction of the (2+1)-dimensional 3-wave system which can be
reduced to a triple of pairwize commuting Monge-Ampere equations. In terms of
the Lame and rotation coefficients Laplace transformations have a natural
interpretation as the symmetries of the Dirac operator, associated with the
(2+1)-dimensional n-wave system. The 2-component Laplace transformations can be
interpreted also as the symmetries of the (2+1)-dimensional integrable
equations of Davey-Stewartson type. Laplace transformations of hydrodynamic
type systems originate from a canonical geometric correspondence between
systems of conservation laws and line congruences in projective space.Comment: 22 pages, Late
Differential systems associated with tableaux over Lie algebras
We give an account of the construction of exterior differential systems based
on the notion of tableaux over Lie algebras as developed in [Comm. Anal. Geom
14 (2006), 475-496; math.DG/0412169]. The definition of a tableau over a Lie
algebra is revisited and extended in the light of the formalism of the Spencer
cohomology; the question of involutiveness for the associated systems and their
prolongations is addressed; examples are discussed.Comment: 16 pages; to appear in: "Symmetries and Overdetermined Systems of
Partial Differential Equations" (M. Eastwood and W. Miller, Jr., eds.), IMA
Volumes in Mathematics and Its Applications, Springer-Verlag, New Yor
Case Report: Imaging immune checkpoint inhibitor-induced yin-yang effects in the brain
BackgroundTreatment with immune checkpoint inhibitors (ICI) can induce durable responses in cancer patients, but it is commonly associated with serious immune-related side effects. Both effects are suggested to be mediated by CD8+ T-cell infiltration. Whole body CD8+ T-cell distribution can be visualized by PET imaging of a 89Zr-labeled anti-humanCD8a minibody, currently investigated in a phase 2b trial.Main bodyAn adult patient diagnosed with metastatic melanoma developed ICI-related hypophysitis after two courses of combined immunotherapy (ipilimumab (3 mg/kg) and nivolumab (1 mg/kg) at 3 weeks interval). On a [89Zr]Zr-crefmirlimab berdoxam PET/CT scan, made 8 days before clinical symptoms occurred, increased CD8+ T-cell infiltration in the pituitary gland was detected. Simultaneously, tracer uptake in a cerebral metastasis was increased, indicating ICI-induced tumor infiltration by CD8+ T-cells.ConclusionsThe observations in this case report underscore the role of CD8+ T-cell in non-tumor tissues in ICI-related toxicity. In addition, it illustrates a potential role for molecular imaging by PET/CT for investigation and monitoring of ICI-induced effects
Signaling in Secret: Pay-for-Performance and the Incentive and Sorting Effects of Pay Secrecy
Key Findings: Pay secrecy adversely impacts individual task performance because it weakens the perception that an increase in performance will be accompanied by increase in pay; Pay secrecy is associated with a decrease in employee performance and retention in pay-for-performance systems, which measure performance using relative (i.e., peer-ranked) criteria rather than an absolute scale (see Figure 2 on page 5); High performing employees tend to be most sensitive to negative pay-for- performance perceptions; There are many signals embedded within HR policies and practices, which can influence employees’ perception of workplace uncertainty/inequity and impact their performance and turnover intentions; and When pay transparency is impractical, organizations may benefit from introducing partial pay openness to mitigate these effects on employee performance and retention
Ablation of Small Liver Metastases Presenting as Foci of Diffusion Restriction on MRI-Results from the Prospective Minimally Invasive Thermal Ablation (MITA) Study
PURPOSE: Liver metastases presenting as small hyperintense foci on diffusion-weighted imaging (DWI) pose a therapeutic challenge. Ablation is generally not possible since these lesions are often occult on ultrasound and CT. The purpose of this prospective study was to assess if small liver metastases (≤10 mm) detected on DWI can be successfully localized and ablated with the Hepatic Arteriography and C-Arm CT-Guided Ablation technique (HepACAGA). MATERIALS AND METHODS: All consecutive patients with small liver metastases (≤10 mm), as measured on DWI, referred for ablation with HepACAGA between 1 January 2021, and 31 October 2023, were included. Re-ablations and ablations concomitant with another local treatment were excluded. The primary outcome was the technical success rate, defined as the intraprocedural detection and subsequent successful ablation of small liver metastases using HepACAGA. Secondary outcomes included the primary and secondary local tumor progression (LTP) rates and the complication rate. RESULTS: A total of 15 patients (26 tumors) were included, with liver metastases from colorectal cancer (73%), neuro-endocrine tumors (15%), breast cancer (8%) and esophageal cancer (4%). All 26 tumors were successfully identified, punctured and ablated (a technical success rate of 100%). After a median follow-up of 9 months, primary and secondary LTP were 4% and 0%, respectively. No complications occurred. CONCLUSION: In this proof-of-concept study, the HepACAGA technique was successfully used to detect and ablate 100% of small liver metastases identified on DWI with a low recurrence rate and no complications. This technique enables the ablation of subcentimeter liver metastases detected on MRI
Expression of the RNA helicase DDX3 and the hypoxia response in breast cancer
<p>Aims: DDX3 is an RNA helicase that has antiapoptotic properties, and promotes proliferation and transformation. In addition, DDX3 was shown to be a direct downstream target of HIF-1α (the master regulatory of the hypoxia response) in breast cancer cell lines. However, the relation between DDX3 and hypoxia has not been addressed in human tumors. In this paper, we studied the relation between DDX3 and the hypoxic responsive proteins in human breast cancer.</p>
<p>Methods and Results: DDX3 expression was investigated by immunohistochemistry in breast cancer in comparison with hypoxia related proteins HIF-1α, GLUT1, CAIX, EGFR, HER2, Akt1, FOXO4, p53, ERα, COMMD1, FER kinase, PIN1, E-cadherin, p21, p27, Transferrin receptor, FOXO3A, c-Met and Notch1. DDX3 was overexpressed in 127 of 366 breast cancer patients, and was correlated with overexpression of HIF-1α and its downstream genes CAIX and GLUT1. Moreover, DDX3 expression correlated with hypoxia-related proteins EGFR, HER2, FOXO4, ERα and c-Met in a HIF-1α dependent fashion, and with COMMD1, FER kinase, Akt1, E-cadherin, TfR and FOXO3A independent of HIF-1α.</p>
<p>Conclusions: In invasive breast cancer, expression of DDX3 was correlated with overexpression of HIF-1α and many other hypoxia related proteins, pointing to a distinct role for DDX3 under hypoxic conditions and supporting the oncogenic role of DDX3 which could have clinical implication for current development of DDX3 inhibitors.</p>
The ternary invariant differential operators acting on the spaces of weighted densities
Over n-dimensional manifolds, I classify ternary differential operators
acting on the spaces of weighted densities and invariant with respect to the
Lie algebra of vector fields. For n=1, some of these operators can be expressed
in terms of the de Rham exterior differential, the Poisson bracket, the Grozman
operator and the Feigin-Fuchs anti-symmetric operators; four of the operators
are new, up to dualizations and permutations. For n>1, I list multidimensional
conformal tranvectors, i.e.,operators acting on the spaces of weighted
densities and invariant with respect to o(p+1,q+1), where p+q=n. Except for the
scalar operator, these conformally invariant operators are not invariant with
respect to the whole Lie algebra of vector fields.Comment: 13 pages, no figures, to appear in Theor. Math. Phy
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