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2.
Proc Natl Acad Sci U S A ; 119(5)2022 02 01.
Article in English | MEDLINE | ID: mdl-35078936

ABSTRACT

The origin of the phenomenon known as the Great Unconformity has been a fundamental yet unresolved problem in the geosciences for over a century. Recent hypotheses advocate either global continental exhumation averaging 3 to 5 km during Cryogenian (717 to 635 Ma) snowball Earth glaciations or, alternatively, diachronous episodic exhumation throughout the Neoproterozoic (1,000 to 540 Ma) due to plate tectonic reorganization from supercontinent assembly and breakup. To test these hypotheses, the temporal patterns of Neoproterozoic thermal histories were evaluated for four North American locations using previously published medium- to low-temperature thermochronology and geologic information. We present inverse time-temperature simulations within a Bayesian modeling framework that record a consistent signal of relatively rapid, high-magnitude cooling of ∼120 to 200 °C interpreted as erosional exhumation of upper crustal basement during the Cryogenian. These models imply widespread, synchronous cooling consistent with at least ∼3 to 5 km of unroofing during snowball Earth glaciations, but also demonstrate that plate tectonic drivers, with the potential to cause both exhumation and burial, may have significantly influenced the thermal history in regions that were undergoing deformation concomitant with glaciation. In the cratonic interior, however, glaciation remains the only plausible mechanism that satisfies the required timing, magnitude, and broad spatial pattern of continental erosion revealed by our thermochronological inversions. To obtain a full picture of the extent and synchroneity of such erosional exhumation, studies on stable cratonic crust below the Great Unconformity must be repeated on all continents.

3.
Nature ; 555(7696): 311, 2018 03 15.
Article in English | MEDLINE | ID: mdl-29542718
4.
Rev Sci Instrum ; 85(3): 035101, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24689614

ABSTRACT

The setup of an apparatus for chemical vapor deposition (CVD) of hexagonal boron nitride (h-BN) and its characterization on four-inch wafers in ultra high vacuum (UHV) environment is reported. It provides well-controlled preparation conditions, such as oxygen and argon plasma assisted cleaning and high temperature annealing. In situ characterization of a wafer is accomplished with target current spectroscopy. A piezo motor driven x-y stage allows measurements with a step size of 1 nm on the complete wafer. To benchmark the system performance, we investigated the growth of single layer h-BN on epitaxial Rh(111) thin films. A thorough analysis of the wafer was performed after cutting in atmosphere by low energy electron diffraction, scanning tunneling microscopy, and ultraviolet and X-ray photoelectron spectroscopies. The apparatus is located in a clean room environment and delivers high quality single layers of h-BN and thus grants access to large area UHV processed surfaces, which had been hitherto restricted to expensive, small area single crystal substrates. The facility is versatile enough for customization to other UHV-CVD processes, e.g., graphene on four-inch wafers.

5.
Oncogene ; 33(46): 5391-6, 2014 Nov 13.
Article in English | MEDLINE | ID: mdl-24213573

ABSTRACT

Lung cancer is the leading cause of deaths in cancer patients in the United States. Identification of new molecular targets is clearly needed to improve therapeutic outcomes of this devastating human disease. Activating mutations in K-Ras oncogene and increased expression of FOXM1 protein are associated with poor prognosis in patients with non-small-cell lung cancer. Transgenic expression of activated Kras(G12D) in mouse respiratory epithelium is sufficient to induce lung adenocarcinomas; however, transcriptional mechanisms regulated by K-Ras during the initiation of lung cancer remain poorly understood. Foxm1 transcription factor, a downstream target of K-Ras, stimulates cellular proliferation during embryogenesis, organ repair and tumor growth, but its role in tumor initiation is unknown. In the present study, we used transgenic mice expressing Kras(G12D) under control of Sftpc promoter to demonstrate that Foxm1 was induced in type II epithelial cells before the formation of lung tumors. Conditional deletion of Foxm1 from Kras(G12D)-expressing respiratory epithelium prevented the initiation of lung tumors in vivo. The loss of Foxm1 inhibited expression of K-Ras target genes critical for the nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) pathways, including Ikbkb, Nfkb1, Nfkb2, Rela, Jnk1, N-Myc, Pttg1 and Cdkn2a. Transgenic overexpression of activated FOXM1 mutant was sufficient to induce expression of these genes in alveolar type II cells. FOXM1 directly bound to promoter regions of Ikbkb, Nfkb2, N-Myc, Pttg1 and Cdkn2a, indicating that these genes are direct FOXM1 targets. FOXM1 is required for K-Ras-mediated lung tumorigenesis by activating genes critical for the NF-κB and JNK pathways.


Subject(s)
Forkhead Transcription Factors/genetics , Gene Expression Regulation, Neoplastic , Lung Neoplasms/genetics , Proto-Oncogene Proteins p21(ras)/genetics , Animals , Antibiotics, Antineoplastic/pharmacology , Blotting, Western , Carcinogenesis/drug effects , Carcinogenesis/genetics , Carcinogenesis/metabolism , Doxorubicin/pharmacology , Epithelium/drug effects , Epithelium/metabolism , Epithelium/pathology , Forkhead Box Protein M1 , Forkhead Transcription Factors/metabolism , Humans , JNK Mitogen-Activated Protein Kinases/metabolism , Lung/drug effects , Lung/metabolism , Lung/pathology , Lung Neoplasms/drug therapy , Lung Neoplasms/metabolism , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , NF-kappa B/metabolism , Promoter Regions, Genetic/genetics , Protein Binding , Proto-Oncogene Proteins p21(ras)/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects
6.
Rev Sci Instrum ; 84(12): 126104, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24387480

ABSTRACT

The construction of an alkali-metal ion source is presented. It allows the acceleration of rubidium ions to an energy that enables the penetration through monolayers of graphene and hexagonal boron nitride. Rb atoms are sublimated from an alkali-metal dispenser. The ionization is obtained by surface ionization and desorption from a hot high work function surface. The ion current is easily controlled by the temperature of ionizer. Scanning Tunneling Microscopy measurements confirm ion implantation.

7.
Oncogene ; 31(34): 3875-88, 2012 Aug 23.
Article in English | MEDLINE | ID: mdl-22139074

ABSTRACT

Macrophages have a key role in tumor-associated pulmonary inflammation that supports the proliferation of tumor cells and promotes lung tumor growth. Although increased numbers of tumor-associated macrophages are linked to poor prognosis in lung cancer patients, little is known regarding the transcriptional mechanisms controlling recruitment of macrophages during lung tumorigenesis. Forkhead Box m1 (Foxm1) transcription factor is induced in multiple cell types within tumor lesions and its increased expression is associated with poor prognosis in patients with lung adenocarcinomas. To determine the role of Foxm1 in recruitment of tumor-associated macrophages, a mouse line with macrophage-specific Foxm1 deletion was generated (macFoxm1(-/-)). Lung tumorigenesis was induced using a 3-methylcholanthrene/butylated hydroxytoluene (BHT; 3,5-di-t-butyl-4-hydroxytoluene) tumor initiation/promotion protocol. Ablation of Foxm1 in macrophages reduced the number and size of lung tumors in macFoxm1(-/-) mice. Decreased tumorigenesis was associated with diminished proliferation of tumor cells and decreased recruitment of macrophages during the early stages of tumor formation. The expression levels of the pro-inflammatory genes iNOS, Cox-2, interleukin-1b (IL-1b) and IL-6, as well as the migration-related genes macrophage inflammatory protein-1 (MIP-1α), MIP-2 and MMP-12, were decreased in macrophages isolated from macFoxm1(-/-) mice. Migration of Foxm1-deficient macrophages was reduced in vitro. The chemokine receptors responsible for monocyte recruitment to the lung, CX(3)CR1 and CXCR4, were decreased in Foxm1-deficient monocytes. In co-transfection experiments, Foxm1 directly bound to and transcriptionally activated the CX(3)CR1 promoter. Adoptive transfer of wild-type monocytes to macFoxm1(-/-) mice restored BHT-induced pulmonary inflammation to the levels observed in control mice. Expression of Foxm1 in macrophages is required for pulmonary inflammation, recruitment of macrophages into tumor sites and lung tumor growth.


Subject(s)
Cell Movement/genetics , Forkhead Transcription Factors/genetics , Lung Neoplasms/genetics , Macrophages/metabolism , Pneumonia/genetics , Adoptive Transfer , Animals , Butylated Hydroxytoluene/analogs & derivatives , CX3C Chemokine Receptor 1 , Chemokine CCL3/genetics , Chemokine CCL3/metabolism , Chemokine CXCL2/genetics , Chemokine CXCL2/metabolism , Cyclooxygenase 2/genetics , Cyclooxygenase 2/metabolism , Flow Cytometry , Forkhead Box Protein M1 , Forkhead Transcription Factors/metabolism , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Interleukin-6/genetics , Interleukin-6/metabolism , Lung Neoplasms/chemically induced , Lung Neoplasms/metabolism , Macrophages/pathology , Matrix Metalloproteinase 12/genetics , Matrix Metalloproteinase 12/metabolism , Mice , Mice, Knockout , Monocytes/metabolism , Monocytes/transplantation , Nitric Oxide Synthase Type II/genetics , Nitric Oxide Synthase Type II/metabolism , Pneumonia/chemically induced , Pneumonia/metabolism , Promoter Regions, Genetic/genetics , Protein Binding , Receptors, CXCR4/genetics , Receptors, CXCR4/metabolism , Receptors, Cytokine/genetics , Receptors, Cytokine/metabolism , Receptors, HIV/genetics , Receptors, HIV/metabolism , Reverse Transcriptase Polymerase Chain Reaction
8.
Oncogene ; 27(30): 4137-49, 2008 Jul 10.
Article in English | MEDLINE | ID: mdl-18345025

ABSTRACT

The forkhead box m1 (Foxm1 or Foxm1b) protein (previously called HFH-11B, Trident, Win or MPP2) is abundantly expressed in human non-small cell lung cancers where it transcriptionally induces expression of genes essential for proliferation of tumor cells. In this study, we used Rosa26-Foxm1 transgenic mice, in which the Rosa26 promoter drives ubiquitous expression of Foxm1 transgene, to identify new signaling pathways regulated by Foxm1. Lung tumors were induced in Rosa26-Foxm1 mice using the 3-methylcholanthrene (MCA)/butylated hydroxytoluene (BHT) lung tumor initiation/promotion protocol. Tumors from MCA/BHT-treated Rosa26-Foxm1 mice displayed a significant increase in the number, size and DNA replication compared to wild-type mice. Elevated tumor formation in Rosa26-Foxm1 transgenic lungs was associated with persistent pulmonary inflammation, macrophage infiltration and increased expression of cyclooxygenase-2 (Cox-2), Cdc25C phosphatase, cyclin E2, chemokine ligands CXCL5, CXCL1 and CCL3, cathepsins and matrix metalloprotease-12. Cell culture experiments with A549 human lung adenocarcinoma cells demonstrated that depletion of Foxm1 by either short interfering RNA transfection or treatment with Foxm1-inhibiting ARF 26-44 peptide significantly reduced Cox-2 expression. In co-transfection experiments, Foxm1 protein-induced Cox-2 promoter activity and directly bound to the -2566/-2580 bp region of human Cox-2 promoter.


Subject(s)
Adenoma/genetics , Forkhead Transcription Factors/genetics , Lung Neoplasms/genetics , Adenoma/chemically induced , Adenoma/pathology , Animals , Butylated Hydroxytoluene , Cyclooxygenase 2/genetics , DNA Replication/drug effects , DNA Replication/genetics , Forkhead Box Protein M1 , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/drug effects , Genetic Predisposition to Disease , Humans , Lung Neoplasms/chemically induced , Lung Neoplasms/pathology , Methylcholanthrene , Mice , Mice, Transgenic , Oligonucleotide Array Sequence Analysis , Promoter Regions, Genetic , Transfection , Tumor Burden , Tumor Cells, Cultured
9.
Stud Health Technol Inform ; 68: 156-60, 1999.
Article in English | MEDLINE | ID: mdl-10724859

ABSTRACT

The Slovenian national health insurance company started a full-scale deployment of the insurance smart card that is at the present used for insurance data and identification purpose only. There is ample capacity on the cards that were selected, to contain much more data than needed for the purely administrative and charging purposes. There are plans to include some basic medical information, donor information, etc. On the other hand, there are no firm plans to use the security infrastructure and the extensive network, connecting the insurance company with the more than 200 self service terminals positioned at the medical facilities through the country to build an integrated medical information system that would be very beneficial to the patients and the medical community. This paper is proposing some possible future developments and further discusses on the security issues involved with such countrywide medical information system.


Subject(s)
Insurance Claim Reporting , Insurance Coverage , National Health Programs , Computer Security , Data Collection , Databases as Topic , Humans , Integrated Advanced Information Management Systems , Slovenia
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