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Scheer M, Neugebauer J, Lingohr T, Zöller J. O.317 Evaluation of undiagnosed mucosa lesions with the VELscope system. J Craniomaxillofac Surg 2008. [DOI: 10.1016/s1010-5182(08)71441-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Scheer M, Wild S, Kuebler A, Zoeller J. P.089 YKL-40 as prognostic biomarker in patients with oral cancer. J Craniomaxillofac Surg 2008. [DOI: 10.1016/s1010-5182(08)71877-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Majerus P, Hain J, Scheer M. T-2 and HT-2 toxin analysis in cereals and cereal products following IAC cleanup and determination via GC-ECD after derivatization. Mycotoxin Res 2008; 24:24-30. [DOI: 10.1007/bf02985267] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 01/23/2008] [Indexed: 10/21/2022]
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Scherer P, Neugebauer J, Ritter L, Mischkowski R, Scheer M, Zöller J. Indikationen für die 3-dimensionale Bildgebung in der Zahnheilkunde. ACTA ACUST UNITED AC 2007. [DOI: 10.1055/s-2007-983917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Uder M, Kohlbacher S, Scheer M, Heckmann M. Zytotoxische Effekte von gadoliniumhaltigem und iodierten Kontrastmitteln an renalen Tubuluszellen in vitro. ROFO-FORTSCHR RONTG 2007. [DOI: 10.1055/s-2006-956212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Heinrich M, Kohlbacher S, Scheer M, Heckmann M. Zytotoxische Effekte eines nichtionischen, monomeren Röntgenkontrastmittels an renalen Tubuluszellen in vitro. ROFO-FORTSCHR RONTG 2007. [DOI: 10.1055/s-2006-956211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Heinrich M, Scheer M, Heckmann M, Bautz W, Uder M. Mechanismen der Zytotoxizität eines nichtionischen monomeren iodhaltigen Kontrastmittels an renalen Tubuluszellen in vitro. ROFO-FORTSCHR RONTG 2007. [DOI: 10.1055/s-2007-977325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Scheer M, Kawari-Mahmoodi N, Neugebauer J, Kübler AC. Pimecrolimus (ELIDEL®) zur Behandlung des Lichen planus mucosae. ACTA ACUST UNITED AC 2006; 10:403-7. [PMID: 17051364 DOI: 10.1007/s10006-006-0030-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Oral lichen planus (OLP) is a common chronic inflammatory disorder with criteria of auto-reactive disease. Treatment consists on topical application of corticosteroids, vitamin A derivates or cyclosporin. Calcineurin inhibitors as tacrolimus and pimecrolimus decrease the production of cytokines and inhibit T-cell proliferation. These substances have recently been introduced for local therapy of chronic inflammatory skin disorders. The aim of our study was to evaluate the effectiveness and side effects of local pimecrolimus in OLP. A group of five patients with histological proven OLP were treated with topical pimecrolimus 1% ointment twice daily to the affected area. Prior to treatment and after 7, 14, 28 and 42 days the lesions were assessed clinically and by photographs. The discomfort scores were evaluated by visual analogue scale (VAS) weekly. All five patients (median age 65.6 years) were female and showed involvement of the buccal mucosa. All lesions showed a reduction of inflammation activity during the treating period. The VAS scores decreased significantly under treatment (p=0,0014). Pimecrolimus ointment was tolerated well with no signs of itching or burning. However, 4 out of 5 patients complained about the reduced adherence properties of the cream. Although no complete remission of OLP has been observed in our series, signs of inflammatory activity of OLP as redness and burning sensations were reduced by topical pimecrolimus. Further controlled randomized studies have to be conducted to compare topical pimecrolimus with topical corticosteroid as standard therapy. The adherence properties of pimecrolimus 1% cream should be improved for intra-oral application.
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Scheer M, Krehwinkel I, Neugebauer J, Zoeller J. P.039 Effect of nonsteroidal antiinflammatory drugs (NSAIDS) on osteoblast cell differentiation in vitro. J Craniomaxillofac Surg 2006. [DOI: 10.1016/s1010-5182(06)60548-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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85
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Rabbels J, Scheer M, Heibel H, Wickenhauser C, Kübler AC. [Neurinoma of the hard palate in an 11-year-old girl. Case report]. ACTA ACUST UNITED AC 2006; 9:400-3. [PMID: 16228186 DOI: 10.1007/s10006-005-0648-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Neurinomas or schwannomas are benign, encapsulated growing tumors of the Schwann cells of the nerve sheets; 25-45% are located in the head and neck region. They are found rarely in the oral cavity. Most of the intraoral schwannomas are located on the tongue. Other less common locations are the buccal mucosa, palate, floor of the mouth, gingiva and lips. The therapy of choice is complete surgical excision. CASE REPORT An 11-year-old girl presented with a 3-month history of painless swelling of the hard palate. CT scan showed a right palatinal mass of 2 cm, reaching into the right maxillary sinus. After complete surgical excision the histological findings showed a neurinoma (Antoni type A). During a 2-year follow-up, there were no signs of recurrence. Because of the benign tumor type we considered the young patient to be healed.
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Heinrich M, Kohlbacher S, Kuhlmann MK, Scheer M, Grgic A, Heckmann M, Uder M. Vergleich zytotoxischer Effekte von gadoliniumhaltigen MRT-Kontrastmitteln mit einem iodhaltigen Röntgenkontrastmittel an renalen Tubuluszellen in vitro. ROFO-FORTSCHR RONTG 2006. [DOI: 10.1055/s-2006-941114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Scheer M, Kübler AC, Manawi NN, Reuther T, Zöller JE. Endosonographische Darstellung der Tumordicke von oralen Plattenepithelkarzinomen und deren Einfluss auf die Inzidenz von Lymphknotenmetastasen. ACTA ACUST UNITED AC 2005; 9:282-9. [PMID: 16133281 DOI: 10.1007/s10006-005-0630-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND The correlation between increasing tumor thickness and lymph node metastases as well as reduced survival in oral cancer has been proven by several studies. In most investigations the tumor thickness was assessed in histological sections. The aim of our prospective study was to assess tumor thickness in oral squamous cell carcinoma (OSCC) by intraoral ultrasonography and to evaluate the predictive value of tumor thickness for incidence of cervical lymph node involvement and survival. PATIENTS AND METHODS A total of 64 patients with primary carcinomas of the oral cavity (stage I-IV) were included. Endosonographic assessment of patients was carried out using a 7.5-mHz probe (Hitachi EUP F334). The primary tumor could be visualized in all cases as a hypoechoic, sometimes irregular mass. RESULTS The average tumor thickness in all tumors was 14+/-7 mm. The N+ patients showed a greater tumor thickness (15+/-7 mm) than N0 OSCCs with 12+/-6 mm (p =0.032, t -test). Less advanced T1/T2 carcinomas revealed a tumor thickness of 10+/-5 mm in contrast to T3/T4 carcinomas with 16+/-7 mm (p <0.001, t-test). The overall survival was reduced in patients with tumors thicker than 14 mm (48.9 versus 28.3 months, p =0,0102 log rank test). CONCLUSION Although this technique facilitates the accurate assessment of tumor thickness in OSCC, only in less advanced tumors could endosonography provide additional information, since these tumors were not visible on CT or MRT scans. Nonetheless endosonography is a fast, cost-effective, and reliable technique for assessment of tumor extent in oral cancer.
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Heibel H, Scheer M, Reuther T, Hahn M, Trittler R, Egle H, Kümmerer K, Kübler AC. Untersuchungen zum Ampicillin/Sulbactam-Spiegel im bestrahlten Unterkieferknochen bei Patienten mit oralen Plattenepithelkarzinomen. ACTA ACUST UNITED AC 2005; 9:214-9. [PMID: 15926086 DOI: 10.1007/s10006-005-0615-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Radiation therapy of the oral and maxillo-facial region increases the risk of an infected osteoradionecrosis (IORN) which is a severe complication. Therefore, perioperative antibiotics for the prophylaxis of ORN is a standard in clinical oncology. The combination therapy of ampicillin and sulbactam (Unacid) promises a good therapeutic and prophylactic outcome. PATIENTS We compared the concentration of Unacid in bone and blood specimens of 22 irradiated patients. All patients were irradiated with 39.6 Gy prior to surgery. The specimens were obtained during the operation 3 weeks after the end of the radiation therapy. RESULTS The concentration of ampicillin/sulbactam in the blood was 124.9/64.5 microg/ml. The bone specimens showed a concentration of ampicillin/sulbactam of 5.54/1.21 microg/g. The concentration of the antibiotic in the bone was three to four times lower than in non-irradiated patients. Nevertheless, this concentration exceeds the minimum inhibitory concentration for bacteria in the oral cavity such as streptcoccae (MHK90<0.25 microg/ml) or staphylococcae (MHK90=0.12-2.0 microg/ml). CONCLUSIONS The results of this study suggest, that Unacid is an effective antibiotic in the prophylaxis of ORN in irradiated patients with head and neck tumors.
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Wölcke U, Kaiser A, Koch W, Scheer M. Eine Synthese O,O-di- und N-mono-acylierterL-Cyclodopaderivate. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19700530718] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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90
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Tiedemann R, Paulus KB, Scheer M, von Kistowski KG, Skírnisson K, Bloch D, Dam M. Mitochondrial DNA and microsatellite variation in the eider duck (Somateria mollissima) indicate stepwise postglacial colonization of Europe and limited current long-distance dispersal. Mol Ecol 2004; 13:1481-94. [PMID: 15140092 DOI: 10.1111/j.1365-294x.2004.02168.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To unravel the postglacial colonization history and the current intercolony dispersal in the common eider, Somateria mollissima, we analysed genetic variation at a part of the mitochondrial control region and five unlinked autosomal microsatellite loci in 175 eiders from 11 breeding colonies, covering the entire European distribution range of this species. As a result of extreme female philopatry, mitochondrial DNA differentiation is substantial both among local colonies and among distant geographical regions. Our study further corroborates the previous hypothesis of a single Pleistocene refugium for European eiders. A nested clade analysis on mitochondrial haplotypes suggests that (i) the Baltic Sea eider population is genetically closest to a presumably ancestral population and that (ii) the postglacial recolonization progressed in a stepwise fashion via the North Sea region and the Faroe Islands to Iceland. Current long-distance dispersal is limited. Differentiation among colonies is much less pronounced at microsatellite loci. The geographical pattern of this nuclear genetic variation is to a large extent explained by isolation by distance. As female dispersal is very limited, the geographical pattern of nuclear variation is probably explained by male-mediated gene flow among breeding colonies. Our study provides genetic evidence for the assumed prominent postglacial colonization route shaping the present terrestrial fauna of the North Atlantic islands Iceland and the Faroes. It suggests that this colonization had been a stepwise process originating in continental Europe. It is the first molecular study on eider duck populations covering their entire European distribution range.
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Abstract
Among individuals with a history of head and neck cancer and tobacco abuse the risk of second primary cancers in the upper aerodigestive tract is high. Chemoprevention of oral squamous cell carcinomas is based on two conditions: Premalignant mucosa lesions are treated with chemopreventive agents in order to prevent malignant conversion (primary prevention). In secondary prevention of oral cancer, after curative therapy patients are treated by chemoprevention in order to reduce the rate of second primaries. This paper presents a comprehensive clinical review of oral cancer prevention studies, highlighting the agents mostly used, such as beta-carotene, alpha-tocopherol, ascorbic acid, and retinoids. Although most intervention trials showed good overall response with these substances, high relapse rates and serious side effects, in most cases related to the retinoid compounds were noticed. In addition, in all prospective randomized chemoprevention trials (CARET, ATBC and PHS) no significant evidence of benefit for supplementation with alpha-tocopherol, beta-carotene or retinyl palmitate was reported.
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Scheer M, Prange W, Petmecky K, Schirmacher P, Zöller JE, Kübler AC. [Evaluation of her-2/neu amplification/overexpression in OSCC with fluorescence in situ hybridization (FISH) and immunohistochemistry]. MUND-, KIEFER- UND GESICHTSCHIRURGIE : MKG 2003; 7:138-45. [PMID: 12764679 DOI: 10.1007/s10006-003-0460-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
INTRODUCTION The human epidermal growth factor receptor ( her-2/ neu) protooncogene encodes a membrane tyrosine kinase with homology to the epidermal growth factor receptor (EGFR). Amplification and protein overexpression have been identified in various solid tumors and a significant association with poor clinical outcome was reported. This investigation was performed to assess the frequency of her-2/ neu overexpression and to compare these results with clinical outcome in OSCC. MATERIAL AND METHODS Archival biopsy specimens from 97 untreated OSCCs were evaluated using a polyclonal antibody A0485 (Dako). Only membrane staining intensity and pattern were evaluated according to the guidelines of the clinical trial assay recommendations (0-3+) for breast carcinoma. Score 0 and 1+ were interpreted as negative for HER-2/NEU protein overexpression and 2+ and 3+ as positive. FISH analysis with directly labeled probes for her-2/ neu and chromosome 17 was performed on the same specimens. The ratio between her-2/ neu and chromosome 17 signals was calculated after selection of 20-40 non-overlapping tumor cells. The tumor was considered amplified if the ratio was above 2. RESULTS In 11 out of 97 biopsies (11.3%) membranous overexpression (score 2+ and 3+) of her-2/ neu was shown by immunohistochemistry. FISH analysis in 42 cases revealed amplification in 14 cases. Concordance between immunohistochemistry and FISH was found in 86%. Clinical-pathological data as well as survival revealed no correlation with her-2/ neu status. DISCUSSION In spite of missing correlation between survival and her-2/ neu overexpression in our study, the predictive value of the her-2/ neu protooncogene in adjuvant therapy in OSCC needs further investigation.
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Drebber U, Scheer M, Zöller JE, Dienes HP. [The central odontogenic fibroma. A rare tumor]. DER PATHOLOGE 2003; 24:136-40. [PMID: 12673504 DOI: 10.1007/s00292-002-0562-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This case report deals with the case history of a 45-year-old male patient who presented with an unusual case of a central odontogenic fibroma which destroyed and replaced the bone mass of the right maxilla. After clinical examination a biopsy was performed and histopathology was consistent with a central odontogenic fibroma with destructive growth. The treatment plan consisted of a surgical resection of the right maxilla. The histopathological evaluation showed a subtotal destruction of the maxillary bone mass by the odontogenic fibroma. Obvious problems concerning the differential diagnosis of odontogenic fibromas as well as current concepts regarding their exact designation and classification are discussed.
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Matys V, Fricke E, Geffers R, Gössling E, Haubrock M, Hehl R, Hornischer K, Karas D, Kel AE, Kel-Margoulis OV, Kloos DU, Land S, Lewicki-Potapov B, Michael H, Münch R, Reuter I, Rotert S, Saxel H, Scheer M, Thiele S, Wingender E. TRANSFAC: transcriptional regulation, from patterns to profiles. Nucleic Acids Res 2003; 31:374-8. [PMID: 12520026 PMCID: PMC165555 DOI: 10.1093/nar/gkg108] [Citation(s) in RCA: 1505] [Impact Index Per Article: 71.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2002] [Revised: 10/11/2002] [Accepted: 10/27/2002] [Indexed: 01/19/2023] Open
Abstract
The TRANSFAC database on eukaryotic transcriptional regulation, comprising data on transcription factors, their target genes and regulatory binding sites, has been extended and further developed, both in number of entries and in the scope and structure of the collected data. Structured fields for expression patterns have been introduced for transcription factors from human and mouse, using the CYTOMER database on anatomical structures and developmental stages. The functionality of Match, a tool for matrix-based search of transcription factor binding sites, has been enhanced. For instance, the program now comes along with a number of tissue-(or state-)specific profiles and new profiles can be created and modified with Match Profiler. The GENE table was extended and gained in importance, containing amongst others links to LocusLink, RefSeq and OMIM now. Further, (direct) links between factor and target gene on one hand and between gene and encoded factor on the other hand were introduced. The TRANSFAC public release is available at http://www.gene-regulation.com. For yeast an additional release including the latest data was made available separately as TRANSFAC Saccharomyces Module (TSM) at http://transfac.gbf.de. For CYTOMER free download versions are available at http://www.biobase.de:8080/index.html.
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Leiner E, Scheer M. Cp*GaCl2 and Cp*2GaCl (Cp*=η1-C5Me5) as starting materials for novel Group 13 element complexes. J Organomet Chem 2002. [DOI: 10.1016/s0022-328x(01)01315-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Scheer M, Drebber U, Kübler A, Zöller JE. [The monthly interesting case No. 52. Plexiform ameloblastoma of the maxillary sinus]. Laryngorhinootologie 2002; 81:122-5. [PMID: 11914950 DOI: 10.1055/s-2002-23112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Nugent-Glandorf L, Scheer M, Samuels DA, Mulhisen AM, Grant ER, Yang X, Bierbaum VM, Leone SR. Ultrafast time-resolved soft x-ray photoelectron spectroscopy of dissociating Br2. PHYSICAL REVIEW LETTERS 2001; 87:193002. [PMID: 11690408 DOI: 10.1103/physrevlett.87.193002] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2001] [Indexed: 05/23/2023]
Abstract
The dissociation of excited state Br2 is probed with the novel technique of ultrafast soft x-ray photoelectron spectroscopy. Excited Br2 molecules are prepared in the dissociative (1)Pi(u) state with 80 fs, 400 nm pulses, and a series of photoelectron spectra are obtained during dissociation with pulses of soft x-ray light (47 nm, 26.4 eV, 250 fs). The formation of Br atoms is readily detected and the data support an extremely fast dissociation time for Br2 on the order of 40 fs. Amplitudes of the pump-probe features reveal that the ionization cross section of atomic Br at 47 nm is approximately 40 times larger than that of Br2.
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Bilodeau RC, Scheer M, Haugen HK. Control of near-threshold detachment cross sections via laser polarization. PHYSICAL REVIEW LETTERS 2001; 87:143001. [PMID: 11580647 DOI: 10.1103/physrevlett.87.143001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2001] [Indexed: 05/23/2023]
Abstract
The behavior of near-threshold cross sections for dissociation of a target into a pair of particles, as described by Wigner's threshold law, can depend sensitively on the angular momentum of the particles. In this Letter, we investigate the near-threshold nonresonant two-photon detachment process in the negative ion of gold. The expected s-wave threshold behavior is observed with linearly polarized light. Closure of the s-wave channel is realized by using circular polarization, allowing the first observation of a d-wave threshold. Practical applications are discussed, including extensions which could prove valuable for investigations of negative ions with near-threshold structure.
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Kübler AC, Scheer M, Zöller JE. Photodynamic therapy of head and neck cancer. ONKOLOGIE 2001; 24:230-7. [PMID: 11455215 DOI: 10.1159/000055085] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Photodynamic therapy (PDT) is an alternative treatment option for tumours of the head and neck. The principle of PDT is based on a photochemical reaction which is initiated by light activation of a photosensitizing drug causing tumour cell death. PDT damage heals mainly by regeneration rather than scarring. Due to this organpreserving principle of PDT, important structures are maintained with very good functional and cosmetic outcome. This article will review the principle of PDT and the different indications for PDT of tumours of the head and neck, focusing on small and advanced tumours of the oral cavity and the larynx as well as papillomatosis of the larynx. A critical review on the literature will be accomplished.
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Abstract
The thermolysis of the phosphinidene complex [Cp*P[W(CO)5]2] (1) in toluene in the presence of tBuC(triple bond)CMe leads to the four-membered ring complexes [[[eta2-C(Me)C(tBu)]Cp*(CO)W(mu3-P)[W(CO)3]][eta4:eta1:eta1-P[W(CO)5]WCp*(CO)C(Me)C(tBu)]] (4) as the major product and [[W[Cp*(CO)2]W(CO)2WCp*(CO)[eta1:eta1-C(Me)C(tBu)]](mu,eta3:eta2:eta1-P2[W(CO)5]] (5). The reaction of 1 with PhC(triple bond)CPh leads to [[W(Co)2[eta2-C(Ph)C(Ph)]][(eta4:eta1-P(W(CO)5]W[Cp*(CO)2)C(Ph)C(Ph)]] (6). The products 4 and 6 can be regarded as the formal cycloaddition products of the phosphido complex intermediate [Cp*(CO)2W(triple bond)P --> W(CO)5] (B), formed by Cp* migration within the phosphinidene complex 1. Furthermore, the reaction of 1 with PhC(triple bond)CPh gives the minor product [[[eta2:eta1-C(Ph)C(Ph)]2[W(CO)4]2][mu,eta1:eta1-P[C(Me)[C(Me)]3C(Me)][C(Ph)](C(Ph)]] (7) as a result of a 1,3-dipolaric cycloaddition of the alkyne into a phosphaallylic subunit of the Cp*P moiety of 1. Compounds 4-7 have been characterized by means of their spectroscopic data as well as by single-crystal X-ray structure analysis.
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