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N 1s core-level shifts from x-ray photoelectron spectra (XPS) are reported for the adsorption products of nitromethane (CH[sub 3]NO[sub 2]) on Si(100). Three spectral peaks are identified and these are associated with specific bonding environments for nitrogen by comparison to predicted core-level shifts from density functional calculations on a range of energetically feasible chemical structures. These species can be classified according to the number of N[Single_Bond]O bonds (zero, one, or two) that they contain and, in this sense, they are comparable to the species believed to exist in oxynitride films on Si. Since the energetically feasible products of room-temperature CH[sub 3]NO[sub 2] adsorption can be identified with more confidence than those resulting from ion bombardment and high-temperature processing in oxynitride films, nitromethane provides a model system that can aid in correlating spectral features with specific atomic-scale structures. This work supports an earlier proposal that the XPS peak of weakest binding energy is due to species with a dangling bond on nitrogen, while the most intense peak is due to the energetically preferred NSi[sub 3] species. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents an infrared study of the adsorption geometry of the H[sub 8]Si[sub 8]O[sub 12] cluster on silicon(100) surfaces. Use of Si(100) samples with buried metallic CoSi[sub 2] as an internal mirror; Mechanism of cluster adsorption on the surfaces; Evidence for the purity of the cluster source.

Examines the adsorption of ethanol in the middle to far-infrared region of silicon 100. Use of surface infrared absorption spectroscopy; Acquisition of infrared spectra in the frequency range; Orientation of ethoxy groups across the silicon dimers near room temperature.

Passivation of semi-insulating indium phosphide surfaces by various types of oxides is investigated with infrared absorption spectroscopy (IRAS) and X-ray photoelectron spectroscopy (XPS). The difficulty in studying oxide-related modes in the 800–1300 cm−1 range is due to the bulk phonon absorption of the InP substrate and has stimulated the optimization of single-pass “external” transmission as well as multiple internal reflection geometries for ex situ and in situ studies, respectively. The nature of oxides prepared commercially for epitaxy (epi-ready) and oxides prepared by wet chemistry is studied as well as the wet chemical etching of such oxides, including the reactivity of InP in various solutions. Combining XPS and polarization-dependent IRAS, we find that epi-ready oxides tend to be porous, and plasma-grown oxides denser. [Copyright &y& Elsevier]

Compares the chemical reactivity of cyclohexene in monolayer Ni surfaces and on a Pt(111) surface. Utilization of the dehydrogenation and hydrogenation of cyclohexene in the process; Investigation of the pathways of cyclohexene; Evidence of unique cyclohexene reactions in monolayer Ni surface.

Using a first-principles density functional approach, we investigate the chemisorption mechanism for the interaction of spherosiloxane (H[sub 8]Si[sub 8]O[sub 12]) clusters on Si(100). Our transition state studies reveal that the chemisorption pathway with the lowest activation barrier corresponds to attachment via Si-O bond cleavage across a surface dimer. Using the relaxed surface structure from this "cracked cluster" model, we calculate Si 2p core-level shifts, including core-hole relaxation effects, and show that the calculated values are in excellent agreement with the positions and intensities of all the experimentally observed core-level shifts. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Patients with metastatic pancreatic ductal adenocarcinoma survive longer if disease spreads to the lung but not the liver. Here we generated overlapping, multi-omic datasets to identify molecular and cellular features that distinguish patients whose disease develops liver metastasis (liver cohort) from those whose disease develops lung metastasis without liver metastases (lung cohort). Lung cohort patients survived longer than liver cohort patients, despite sharing the same tumor subtype. We developed a primary organotropism (pORG) gene set enriched in liver cohort versus lung cohort primary tumors. We identified ongoing replication stress response pathways in high pORG/liver cohort tumors, whereas low pORG/lung cohort tumors had greater densities of lymphocytes and shared T cell clonal responses. Our study demonstrates that liver-avid pancreatic ductal adenocarcinoma is associated with tolerance to ongoing replication stress, limited tumor immunity and less-favorable outcomes, whereas low replication stress, lung-avid/liver-averse tumors are associated with active tumor immunity that may account for favorable outcomes., Competing Interests: Competing interests: Disclosures relevant to PDAC are as follows. R.C.S. declares Scientific Advisory Board (SAB)/consultancy for Rappta Therapeutics, PanCAN, PRECEDE, MOHCCN & PanCuRx Canada and Precision Panc CRUK; sponsored research for Cardiff Oncology, AstraZeneca. G.B.M. declares SAB/consultancy for Amphista, Astex, AstraZeneca, BlueDot, Chrysallis Biotechnology, Ellipses Pharma, ImmunoMET, Infinity, Ionis, Lilly, Medacorp, Nanostring, Nuvectis, PDX Pharmaceuticals, Roche, Signalchem Lifesciences, Tarveda, Turbine and Zentalis Pharmaceuticals; Stock/options/financial for AstraZeneca, Catena Pharmaceuticals, ImmunoMet, SignalChem, Tarveda and Turbine; licensed technology HRD assay to Myriad Genetics and Digital Spatial Profiler patents with Nanostring. L.M.C. declares consulting services for Cell Signaling Technologies, AbbVie, the Susan G Komen Foundation and Shasqi, received reagents and/or research support from Cell Signaling Technologies, Syndax Pharmaceuticals, ZelBio, Hibercell and Acerta Pharma, and participates in advisory boards for Pharmacyclics, Syndax, Carisma, Verseau, CytomX, Kineta, Hibercell, Cell Signaling Technologies, Alkermes, Zymeworks, Genenta Sciences, Pio Therapeutics, PDX Pharmaceuticals, NextCure, the AstraZeneca Partner of Choice Network, the Lustgarten Foundation and the NIH–NCI-Frederick National Laboratory Advisory Committee. J.R.B. declares SAB for Perthera, Advisory for IDEAYA and is an editor for Springer and Taylor & Francis publishing. The other authors declare no competing interests., (© 2025. The Author(s).)

Global distribution of hepatocellular carcinomas (HCCs) is dominated by its incidence in developing countries, accounting for >700,000 estimated deaths per year, with dietary exposures to aflatoxin (AFB 1 ) and subsequent DNA adduct formation being a significant driver. Genetic variants that increase individual susceptibility to AFB 1 -induced HCCs are poorly understood. Herein, it is shown that the DNA base excision repair (BER) enzyme, DNA glycosylase NEIL1, efficiently recognizes and excises the highly mutagenic imidazole ring-opened AFB 1 -deoxyguanosine adduct (AFB 1 -Fapy-dG). Consistent with this in vitro result, newborn mice injected with AFB 1 show significant increases in the levels of AFB 1 -Fapy-dG in Neil1 -/- vs. wild-type liver DNA. Further, Neil1 -/- mice are highly susceptible to AFB 1 -induced HCCs relative to WT controls, with both the frequency and average size of hepatocellular carcinomas being elevated in Neil1 -/- The magnitude of this effect in Neil1 -/- mice is greater than that previously measured in Xeroderma pigmentosum complementation group A (XPA) mice that are deficient in nucleotide excision repair (NER). Given that several human polymorphic variants of NEIL1 are catalytically inactive for their DNA glycosylase activity, these deficiencies may increase susceptibility to AFB 1 -associated HCCs., Competing Interests: The authors declare no conflict of interest.

In this Letter, we investigate the Si/SiO(2) interface structure formed by the chemisorption of H8Si8O12 and other spherosiloxane clusters on Si(100). Using transition state calculations, we clearly demonstrate that the clusters do not bond to the Si(100) surface via single vertex attachment as proposed previously, but rather attach via Si-O bond cleavage. This alternative cracked cluster geometry allows us to predict the photoemission features of spherosiloxane clusters on Si(100) without invoking second nearest neighbor effects.

This paper combines data from two surveys, one in 1986 and one in 1992, which used the same instrument. Practice problems, and responses to the problems, were found to differ according to the number of years in practice, validating a stage explanation of professional growth.

In a mailed questionnaire study of a 1/3 sample of recent graduates of the UOP School of Dentistry (57 percent response rate), most respondents felt competent in the majority of procedures they perform. Most procedures not performed were not performed because they are easily referred. Sources of learning about procedures differed according to frequency of performance (frequently performed: 95 percent-dental school; infrequently performed: 82 percent-continuing education). Differences also were noted according to years of practice.

This paper combines data from two surveys, one in 1986 and one in 1992, which used the same instrument. Practice problems, and responses to the problems, were found to differ according to the number of years in practice, validating a stage explanation of professional growth.