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  • 1
    Electronic Resource
    Electronic Resource
    Carbon incorporation into Si at high concentrations by ion implantation and solid phase epitaxy (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 637-646 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the incorporation of heavily supersaturated C into Si using solid-phase epitaxy (SPE) of implanted amorphous layers. The strain in the Si1−xCx/Si heterostructures was measured using rocking curve x-ray diffraction. The microstructure and defect introduction were examined using ion channeling and transmission electron microscopy (TEM). The fraction of C located on substitutional lattice sites in the Si was monitored using Fourier transform infrared absorption spectroscopy and ion channeling at resonance energies. Carbon-depth profiles were monitored by secondary ion mass spectroscopy. The metastable solubility limit for the incorporation of C into Si by SPE was found to be 3.0–7.0×1020 atoms/cm3, which is over three orders of magnitude above the equilibrium solubility at the Si melting point. This limit was determined by the ability to regrow without the introduction of microtwins and stacking faults along {111} planes. We postulate the local bond deformation resulting from the atomic size difference between C and Si leads to the faceting of the amorphous–crystalline interface and allows defect introduction, thus limiting the C supersaturations achieved in Si by SPE. It was also found that the defect density in the regrown alloys could be reduced by higher SPE regrowth temperatures in rapid thermal anneal processing. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360806
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  • 2
    Electronic Resource
    Electronic Resource
    Oxygen-related vibrational modes produced in Czochralski silicon by hydrogen plasma exposure (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 2337-2342 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Plasma hydrogenation of Czochralski Si has been performed to investigate the introduction of Si–O stretch modes and their correlation with thermal donor formation. Plasma hydrogenation at 275 °C introduces a well-resolved vibrational absorption band at 1005 cm−1, while absorption due to electronic excitations for thermal donors remains weak. We attribute this band to a Si–O precursor center for thermal donor formation, and suggest it is the oxygen dimer center discussed in other studies of oxygen in Si. Vibrational modes introduced at 990 and 1000 cm−1 during post-hydrogenation furnace annealing at 400 °C correlate with thermal donors TD2 and TD3, respectively. Stretch frequencies for Si–O in thermal donor centers are compared to those for oxygen aggregates in oxygen-implanted and electron-irradiated Si.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362658
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  • 3
    Electronic Resource
    Electronic Resource
    Implanted nitrogen in germanium (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 153-154 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The first measurements of localized vibrational modes for N in crystalline Ge are reported. Nitrogen isotopes were implanted into Ge, and infrared absorption measurements were made at 80 K after laser annealing. Four isotopic mass-shifted infrared absorption bands are observed. Two of the bands in Ge are analogous to those for N pairs in crystalline Si and are assigned to N pairs in Ge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99035
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  • 4
    Electronic Resource
    Electronic Resource
    Extended infrared response of InAsSb strained-layer superlattices (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 831-833 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Strained-layer superlattices of InAsSb were grown with low densities of dislocations and microcracks for optical characterization to determine the suitability of these structures for infrared photodetectors. Infrared transmission measurements revealed absorption throughout the 8–12 μm region and extended to longer wavelengths than predicted from consideration of the tensile strain-induced band-gap shift in a type-I superlattice. We conclude that a type-II superlattice occurs in the InAsSb system for alloy compositions 〉60% Sb.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99298
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  • 5
    Electronic Resource
    Electronic Resource
    Self-interstitials and the 935 cm−1 band in silicon (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 870-872 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Substitutional carbon in Czochralski Si is found to decrease the formation rate for a 935 cm−1 infrared absorption band under neutron irradiation while that for a 965 cm−1 band (interstitial carbon trapped at interstitial oxygen) increases. The observations support a controversial previous assignment of the 935 cm−1 band to a center with interstitial Si trapped by interstitial oxygen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101625
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of high carbon concentration upon oxygen precipitation and related phenomena in CzSi (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 849-855 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Effects of high carbon concentration upon oxygen precipitation and related phenomena in Czochralski (Cz) silicon have been investigated by combining various furnace and rapid thermal anneals. Our data show that oxide precipitate (OP) density, estimated from changes in interstitial oxygen concentration (ΔOi), increases with increasing substitutional carbon concentration, Cs, while thermal donor (TD) formation is inhibited at high Cs. Even though ΔOi increases monotonically with Cs, synchrotron radiation section topographs of processed high carbon content wafers (Cs∼4 ppma) exhibit Pendellösung fringes, indicating a strain-free bulk state. Our transmission electron microscope and optical microscopic data also show very few resolvable structural defects associated with precipitates inside the bulk Si. Using a thermodynamic and kinetic model, we attempt to explain: (1) reduced thermal donor formation, (2) lack of bulk stress notwithstanding high ΔOi, and (3) predominantly polyhedral precipitate morphologies in high carbon content CzSi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.341936
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  • 7
    Electronic Resource
    Electronic Resource
    Reply to "Comment on ‘Rapid thermal annealing and regrowth of thermal donors' '' [J. Appl. Phys. 59, 3495 (1986)] (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 2682-2683 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An activation-energy determination from isothermal-annealing experiments without establishing an order for decay kinetics is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337903
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  • 8
    Electronic Resource
    Electronic Resource
    Neoadjuvant chemotherapy for gastric cancer: Update (1995)
    Springer
    World journal of surgery 19 (1995), S. 509-516 
    Details
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé On a récemment souligné l'intérêt, chez les patients ayant un cancer gastrique, de la chimiothérapie néoadjuvante pour améliorer le taux de résecabilité complète des tumeurs, pour combattre des métastases systémiques et pour prolonger la survie. En effet, les études disponibles indiquent que la chimiothérapie néoadjuvante est faisable sans augmenter ni la mortalité ni la morbidité. Comparée aux résultats obtenus aujourd'hui par la résection primitive associée à un curage, la chimiothérapie préopératoire, par contre, ne s'est pas montrée capable d'améliorer le taux de résecabilité des tumeurs estimées résécables à priori. Chez le patient ayant un cancer avancé ou non résécable, par contre, la chimiothérapie préopératoire peut réduire considérablement le volume tumoral et augmenter la possibilité de résection. Chez le patient qui répond à la chimiothérapie et qui a, par la suite, une résection complète de la tumeur, la survie apparaît donc améliorée. An raison d'imperfections dans la conception même de certaines de ces études, cependant, il n'est pas possible de tirer des conclusions définitives. Des études contrôlées, et randomisées, sont clairement nécessaires. Un «staging» préthérapeutique exact, une technique de résection et de curage standardisée, une évaluation diligente de la pièce après résection ainsi qu'un suivi rigoureux sont essentiels dans l'élaboration de ces essais pour identifier le sous-groupe de patients ayant un cancer gastrique qui pourraient bénéficier de la chimiothérapie néoadjuvante.
    Abstract: Resumen En tiempos recientes ha merecido creciente atención la quimioterapia neoadyuvante en un intento por aumentar las tasas de resecciones tumorales completas, combatir metástasis sistémicas y prolongar la supervivencia en pacientes con cáncer gástrico. La información disponible indica que la terapia neoadyuvante es factible y no aumenta la morbilidad ni la mortalidad postoperatorias. En comparación con los resultados que actualmente se obtienen con la resección primaria y la linfadenectomía, la quimioterapia preoperatoria hasta ahora, sin embargo, ha fallado en cuanto a demostrar un claro incremento en la rata de resección completa del tumor en los pacientes con cáncer gástrico resecable. En los pacientes con cáncer gástrico localmente avanzado o no resecable, la quimioterapia preoperatoria puede causar una reducción sustancial de la masa local-regional, y, por lo tanto, un incremento en la tasa de resección. Esto parece traducirse en un beneficio de supervivencia en aquellos pacientes que responden a la quimioterapia y que luego son sometidos a una resección completa de su tumor. Debido a severas limitaciones en el diseño de los informes publicados, no es posible derivar conclusiones definitivas a partir de la información disponible. Por lo tanto, aparece clara la necesidad de realizar ensayos clínicos prospectivos y randomizados. Una muy exacta estadificación tumoral preterapéutica, la resección estandarizada y la técnica de linfadenectomía, el examen meticuloso del espécimen resecado y un cuidadoso seguimiento son esenciales cuando se diseñen ensayos clínicos y se pretenda identificar subgrupos de pacientes que puedan beneficiarse de quimioterapia neoadyuvante para el carcinoma gástrico.
    Notes: Abstract Neoadjuvant chemotherapy has recently received increasing attention in an attempt to increase the rate of complete tumor resections, combat systemic metastases, and prolong survival in patients with gastric cancer. The available data indicate that neoadjuvant chemotherapy is feasible and does not increase postoperative morbidity and mortality. Compared to the results that can today be obtained with primary resection and lymphadenectomy, however, preoperative chemotherapy has so far failed to show a clear increase in the rate of complete tumor removal in patients with resectable gastric cancer. In patients with locally advanced or unresectable gastric cancer, preoperative chemotherapy may cause substantial reduction in locoregional tumor mass and thus increase the resection rate. This finding appears to translate into a survival benefit for those who respond to chemotherapy and have subsequent complete tumor resection. Because of severe shortcomings in the study design of the published reports, definite conclusions cannot be drawn from the available studies. Randomized controlled prospective trials are therefore clearly warranted. Exact pretherapeutic tumor staging, standardized resection and lymphadenectomy techniques, diligent evaluation of the resected specimen, and close follow-up are essential when designing these trials to identify subgroups of patients who may benefit from neoadjuvant chemotherapy for gastric carcinoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294711
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  • 9
    Electronic Resource
    Electronic Resource
    Problem of proximal third gastric carcinoma (1995)
    Springer
    World journal of surgery 19 (1995), S. 523-531 
    Details
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé La prévalence du cancer du tiers proximal de l'estomac augmente rapidement en Occident. Une analyse des facteurs pronostiques indique que le pronostic médiocre de ces tumeurs est, pour au moins une part, du au fait que les patients se présentent tardivement avec des tumeurs avancées. La classification TNM actuelle sous-clase ces tumeurs habituellement car elle ne tient pas compte de la localisation partiellement rétropéritonéale des lésions. Après correction tenant compte de ce facteur, la localisation proximale n'est pas à elle seule un facteur de mauvais pronostic. Puisque ces tumeurs se prêtent bien à un curage radical, il faut tenir compte des ganglions rétropéritonéaux lorsqu'on entreprend l'adénolymphectomie pour cancer du tiers proximal de l'estomac. Afin d'éviter les fistules et d'autres complications, il faut s'efforcer de pratiquer une splénectomie sans pancréatectomie lorsque l'on entreprend ce curage, qui doit être adapté aux lésions. En raison de la prévalence élevée du type 《intestinal》 de ces cancers, les marges de sécurité peuvent être moins importantes, c'est à dire qu'une gastrectomie totale avec une résection transhiatale du tiers distal de l'oesophage suffit habituellement à assurer une ablation complète de la lésion proximale.
    Abstract: Resumen La prevalencia del cáncer gástrico del tercio proximal del estómago se incrementa rápidamente en el mundo occidental. El análisis de los factores de pronóstico indica que el reconocido mal pronóstico de estos tumores está generalmente asociado, por lo menos en parte, con su presentación tardía y avanzado estadío. La actual clasificación TNM tiende a subestadificarlos, por cuanto no tiene en cuenta la parte de ubicación retroperitoneal del tumor. Una vez que se corrige la clasificación TNM, la ubicación proximal del tumor deja tener influencia en la sobrevida. Puesto que estos tumores se benefician principalmente con la disección ganglionar radical, el drenaje linfático retroperitoneal debe ser considerado cuando se realiza una linfadenectomía por cáncer del tercio proximal del estómago. Con el objeto de evitar la fistula pancreática y su correspondiente morbilidad, se dèbe practicar una esplenectomía con preservación del páncreas y adaptar la linfadenectomía cuando se realice una disección ganglionar extendida al retroperitoneo. Por razón de la alta prevalencia de tumores del tipo “intestinal” en el tercio proximal del estómago, es posible limitar la extensión de los márgenes de resección, o sea que una gastrectomía total con resección transhiatal del esófago distal generalmente es suficiente para lograr la remoción completa del tumor sobre el bordc oral.
    Notes: Abstract The prevalence of proximal third gastric carcinoma increases rapidly in the Western world. An analysis of prognostic factors indicates that the poor prognosis usually associated with these tumors is due at least in part to late presentation and advanced tumor stages. The current TNM classification usually understages these tumors because it does not take the partly retroperitoneal location of the proximal stomach into account. After correction of the TNM classification a proximal tumor location has no influence on survival. Because these tumors benefit most from radical lymph node dissection, the retroperitoneal lymphatic drainage must be taken into account when performing lymphadenectomy for proximal third gastric cancer. To avoid pancreatic fistulas and the associated morbidity, a pancreas-preserving splenectomy and lymphadenectomy should be adapted if an extended lymph node resection of the retroperitoneum is performed. Because of the high prevalence of “intestinal type” tumors in the proximal third of the stomach the extent of the luminal resection margins can be limited; that is, a total gastrectomy with transhiatal resection of the distal esophagus usually suffices to achieve complete tumor removal at the oral margin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294713
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  • 10
    Electronic Resource
    Electronic Resource
    Multimodal treatment for squamous cell esophageal cancer (1995)
    Springer
    World journal of surgery 19 (1995), S. 198-204 
    Details
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'association chimiothérapie et radiochimiothérapie préopératoire a reçu beaucoup d'attention dernièrement. Alors que plusieurs études prospectives randomisées n'ont pu démontrer les bénéfices d'une thérapeutique néoadjuvante chez des patients ayant une tumeur potentiellement résécable, la chimiothérapie seule ou associée à la radiothérapie préopératoires semble augmenter le taux de résécablitié et la survie chez les patients avant des tumeurs locorégionates. La plupart des études disponibles démontrent une amélioration de survie lorsque la thérapeutique est multimodale, lorsque la réponse histologique initiale à la chimiothérapie préoperatoire est positive, c'est à dire, s'il n'y ait aucune tumeur visible dans la pièce opératoire. La radiochimiothérapie préopératoire augmente le taux de réponse et améliore le contrôle local, par rapport à la chimiothérapie seule, mais elle augmente également la mortalité et la morbidité périopératoires. Les métastases à distance ne sont pas bien controlées par la radiochimiothérapeutique associée. Ces donnécs indiquent que la thérapeutique néoadjuvante est encore au stade expérimental chez le patient ayant un cancer de l'oesophage résecable, mais est en voie de devenir la thérapeutique de l'avenir en ce qui concerne les tumeurs locorégionales. La recherche actuelle cherche à identifier les patients qui répondront au mieux à cette thérapeutique néoadjuvante. De plus, des drogues moins toxiques et plus efficaces sont nésessaires pour améliorer le taux de réponse et combattre les récidivcs systémiques. Enfin, des études randomisécs sont essentielles pour évaluer le rôle, l'étendue et le meilleur moment de la résection chirurgicale dans cette optique thérapeutique chez le patient ayant un cancer épithélial de l'oesophage.
    Abstract: Resumen La quimioterapia preoperatoria (CTx) y la combinación radioquimioterapia (RTx/CTx) en los pacientes con carcinoma escamocelular del esófago se constituye en motivo reciente de atención. En tanto que varios ensayos prospectivos y randomizados no han logrado demostrar beneficio de la terapia neoadyuvante en pacientes con tumores potencialmente resecables, la CTx preoperatoria o la combinación RTx/CTx parece aumentar la tasa de resección, la tasa de resección tumoral completa y el tiempo de sobrevida en los pacientes con tumores localmente avanzados. La mayoría de los estudios disponibles demuestra que el beneficio de supervivencia puede esperarse en los pacientes que exhiben respuesta histopatológica completa al tratamiento preoperatorio, o sea aquellos en que no se encuentran células viables en el espécimen de resección. Una combinación de RTx/CTx preoperatoria aumenta las tasas de respuesta y mejora el control tumoral local en comparación con la CTx preoperatoria sola, pero también se asocia con morbilidad y mortalidad perioperatorias considerables. Las recurrencias tumorales a distancia todavía no pueden ser bien controladas mediante los protocolos de terapias combinadas actualmente en boga. Estos datos indican que la terapia neoadyuvante debe ser considerada todavía como de tipo investigativo en los pacientes con carcinoma esofágico potencialmente resecable, pero que tal vez pronto puedan convertirse en tratamiento estandarizado en los pacientes con tumores localmente avanzados. La investigación debe enfocarse sobre las modalidades que permiten la identificación preterapéutica de aquellos pacientes que habrán de responder a la terapia neoadyuvante. Por lo demás, se requieren regímenes terapéuticos preoperatorios más eficaces y menos tóxicos con el objeto de aumentar las tasas de respuesta y de controlar las recurrencias sistémicas. Finalmente, es esencial ejecutar estudios prospectivos randomizados para determinar el rol, la magnitud y el momento de realizar la resección quirúrgica en el aproche multimodal de los pacientes con carcinoma escamocelular del esófago.
    Notes: Abstract Preoperative chemotherapy (CTx) and combination radiochemotherapy (RTx/CTx) in patients with squamous cell esophageal carcinoma has recently received increasing attention. Although several prospective randomized trials could not show any benefit of neoadjuvant therapy in patients with potentially resectable tumors, preoperative CTx and combination RTx/CTx appear to increase the resection rate, the rate of complete tumor resection, and survival time in patients with locally advanced tumors. Most available studies show that a survival benefit from multimodal therapy can be expected primarily in patients who have a complete histopathologic response to preoperative treatment (i.e., no viable tumor in the resected specimen). Preoperative RTx/CTx increases the response rate and improves local tumor control compared to preoperative CTx alone, but it is associated with substantial perioperative mortality and morbidity. Distant tumor recurrences are insufficiently controlled with current combined modality protocols. These data indicate that neoadjuvant therapy must be considered investigational in patients with potentially resectable esophageal carcinoma but may soon become standard in patients with locally advanced tumors. Research must focus on modalities that allow pretherapeutic identification of those patients who will respond to neoadjuvant therapy. Furthermore, more effective and less toxic preoperative therapy regimens are required to increase the response rates and combat systemic recurrences. Finally, randomized prospective studies are essential to assess the role, extent, and timing of surgical resection for the combined modality approach to patients with squamous cell esophageal carcinoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308626
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