bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Gastrointestinal Hormones and Leptin After Roux‐en‐Y Gastric Bypass Surgery
Authors: Beckman Lauren M. , Beckman Tiffany R. , Sibley Shalamar D. , Thomas William , Ikramuddin Sayeed , Kellogg Todd A. , Ghatei Mohammad A. , Bloom Stephen R. , le Roux Carel W. , Earthman Carrie P.
Published: March 2011

Background: Roux‐en‐Y gastric bypass (RYGB) imparts long‐term weight loss, the mechanisms for which are not well understood. Changes in leptin and gastrointestinal (GI) hormones, including glucagon‐like peptide 1 (GLP‐1), peptide YY (PYY), and ghrelin, may contribute to the relative success of RYGB compared with conventional weight loss methods. This study evaluated changes in GI hormones and leptin post‐RYGB. The study also evaluated whether GI hormones differed after a short‐term dose of protein or fat. Methods: GLP‐1, PYY, ghrelin, and leptin were assessed in 16 women before RYGB and up to 1 year after RYGB. Plasma was collected before and at several times after a short‐term equicaloric dose of protein or fat. Results: GLP‐1 area under the curve (AUC) increased at week 6 and 1 year in the fat beverage (FAT‐BEV) group compared with baseline. PYY AUC remained elevated at 1 year in the FAT‐BEV group. Ghrelin AUC decreased at week 2, week 6, and 1 year in the protein beverage (PRO‐BEV) group compared with baseline. Ghrelin AUC was lower in the PRO‐BEV group compared with the FAT‐BEV group at week 6. Fasted leptin decreased at all visits in both groups and was lower in the FAT‐BEV group compared with the PRO‐BEV group at 1 year. Conclusions: Changes from baseline were evident for all GI hormones and leptin; some differences were evident soon after surgery (ghrelin, leptin), whereas others were maintained long term (GLP‐1, PYY, ghrelin, leptin). In response to a short‐term stimulus, protein suppressed ghrelin and fat potently stimulated GLP‐1 and PYY. Future work in this area is warranted.
When Early Enteral Feeding Is Not Possible in Critically Ill Patients
Authors: Cahill Naomi E. , Murch Lauren , Jeejeebhoy Khursheed , McClave Stephen A. , Day Andrew G. , Wang Miao , Heyland Daren K.
Published: March 2011

Background: Early enteral nutrition (EN) is the preferred strategy for feeding the critically ill; however, it is not always possible to initiate EN within the recommended 24 to 48 hours. When these situations arise, controversy exists whether to start feeding early via the parenteral route or to delay feeding until EN can be provided. Methods: A multicenter, international, observational study examined nutrition practices in intensive care units (ICUs). Eligible patients were critically ill patients with a medical diagnosis who remained in the ICU for >72 hours and received EN >48 hours after admission. Data were collected on site, including patient characteristics, daily nutrition practices, and outcomes at 60 days. Nutrition and clinical outcomes were compared between 3 groups of patients: (1) early parenteral nutrition (PN) (<48 hours after admission) and late EN (>48 hours after admission), (2) late PN and late EN, and (3) late EN and no PN. Results: Of the 703 patients who met our inclusion criteria, 541 (77.0%) medical patients received late EN and no PN. In patients receiving late EN and PN, 83 (11.8%) received early PN and 79 (11.2%) received late PN. Adequacy of calories and protein from total nutrition was highest in the early PN group (74.1% ± 21.2% and 71.5% ± 24.9%, respectively) and lowest in the late EN group (42.9% ± 21.2% and 38.7% ± 21.6%) (P < .001). The proportion of patients dead or remaining in hospital was significantly higher for early PN compared with late EN and PN (unadjusted hazard ratio for early PN = 0.55; 95% confidence interval, 0.37–0.83, P = .015). However, this difference did not remain significant (P = .65) after adjustment for baseline characteristics. Conclusions: The results suggest that initiating PN early, when it is not possible to feed enterally early, may improve provision of calories and protein but is not associated with better clinical outcomes compared with late EN or PN.
Low Serum Citrulline Concentration Correlates With Catheter‐Related Bloodstream Infections in Children With Intestinal Failure
Authors: Hull Melissa A. , Jones Brian A. , Zurakowski David , Raphael Bram , Lo Clifford , Jaksic Tom , Duggan Christopher
Published: March 2011

Background: Serum citrulline concentration is used as a biomarker of enterocyte mass and enteral tolerance, and low serum concentrations are correlated with bacteremia in immunosuppressed adults undergoing hematopoietic stem cell transplant. The authors sought to determine if citrulline was associated with the development of catheter‐related bloodstream infections (CRBSIs) in children with intestinal failure. Methods: Data were reviewed from 66 children treated in a multidisciplinary intestinal rehabilitation program, who had serum concentration citrulline measured between January 2007 and August 2009. All patients had a diagnosis of intestinal failure requiring parenteral nutrition (PN) support. Exclusion criteria included central venous catheter in situ <30 days, creatinine clearance <20 mL/minute, or a history of organ transplant/immunosuppression. Results: A total of 15 patients were excluded because of the above criteria. In this cohort of 51 patients, 26 (51%) developed CRBSIs. Both groups were similar in terms of gestational age, diagnosis, nutrition status, and biochemical liver function tests. The mean (± standard deviation [SD]) minimum serum citrulline concentration was significantly lower in patients who developed CRBSIs (6.7 ± 4.6 µmol/L) than in those who did not (11.3 ± 6.4 µmol/L, P = .004). Multivariate logistic regression analysis identified lower minimum serum citrulline concentration and longer central venous catheter duration as independently associated with CRBSI (P = .003 and P = .038, respectively). Conclusions: Low serum citrulline concentration and longer central venous catheter time are independently associated with CRBSI in children with intestinal failure. Serum citrulline concentration may be a useful biomarker to identify patients with intestinal failure who are at high risk of developing a CRBSI.
Novel type II anti-CD20 monoclonal antibody (GA101) evokes homotypic adhesion and actin-dependent, lysosome-mediated cell death in B-cell malignancies
Authors: Alduaij Waleed , Ivanov Andrei , Honeychurch Jamie , Cheadle Eleanor J. , Potluri Sandeep , Lim Sean H. , Shimada Kazuyuki , Chan Claude H. T. , Tutt Alison , Beers Stephen A. , Glennie Martin J. , Cragg Mark S. , Illidge Tim M.
Published: March 2011

The anti-CD20 mAb rituximab has substantially improved the clinical outcome of patients with a wide range of B-cell malignancies. However, many patients relapse or fail to respond to rituximab, and thus there is intense investigation into the development of novel anti-CD20 mAbs with improved therapeutic efficacy. Although Fc-FcγR interactions appear to underlie much of the therapeutic success with rituximab, certain type II anti-CD20 mAbs efficiently induce programmed cell death (PCD), whereas rituximab-like type I anti-CD20 mAbs do not. Here, we show that the humanized, glycoengineered anti-CD20 mAb GA101 and derivatives harboring non-glycoengineered Fc regions are type II mAb that trigger nonapoptotic PCD in a range of B-lymphoma cell lines and primary B-cell malignancies. We demonstrate that GA101-induced cell death is dependent on actin reorganization, can be abrogated by inhibitors of actin polymerization, and is independent of BCL-2 overexpression and caspase activation. GA101-induced PCD is executed by lysosomes which disperse their contents into the cytoplasm and surrounding environment. Taken together, these findings reveal that GA101 is able to potently elicit actin-dependent, lysosomal cell death, which may potentially lead to improved clearance of B-cell malignancies in vivo.
Diet folate, DNA methylation and genetic polymorphisms of MTHFRC677T in association with the prognosis of esophageal squamous cell carcinoma
Authors: Lu Cheng , Xie Hui , Wang Fengliang , Shen Hongbing , Wang Jianming
Published: March 2011

Background

Folic acid may affect the development of human cancers. However, few studies have evaluated the consumption of diet folate in the prognosis of patients with esophageal squamous cell carcinoma (ESCC).

Methods

One hundred and twenty five ESCC patients underwent esophagectomy between January 2005 and March 2006 in the Yangzhong People's Hospital were recruited and followed up. The effects of diet folate, aberrant DNA methylation of selected genes and methylenetetrahydrofolate reductase (MTHFR) C677T genetic polymorphisms on the prognosis of ESCC were evaluated by using Cox proportional hazard regression models.

Results

Our analysis showed an inverse association between diet folate intake and the risk of death after esophagectomy. The median survival time was 3.06 years for low or moderate folate consumption and over 4.59 years for high folate consumption. After adjusting for potential confounders, the hazard ratios (95% confidence interval) [HRs (95% CI)] were 0.72 (0.36-1.46) for moderate and 0.39 (0.20-0.78) for high folate intake, respectively (P for trend = 0.007). This preventive effect was more evident in patients carrying MTHFR 677CC genotype. No significant relation was observed between aberrant DNA methylation of P16, MGMT and hMLH1 gene, as well as MTHFR C677T genetic polymorphisms and the prognosis of ESCC.

Conclusions

Our research indicated that diet folate intake may have benefits on the prognosis of ESCC after esophagectomy. From a practical viewpoint, the findings of our study help to establish practical intervention and surveillance strategies for managements of ESCC patients and can finally decrease the disease burden.
What Happens When Pornography Ends in Marriage: The Uniformity of Pleasure in Fanny Hill
Authors: Haslanger Andrea
Published: March 2011

This essay argues that John Cleland's pornographic novel, Fanny Hill , conceals coercion by employing the language of materialism to suggest that all sex, commercial or not, produces pleasure. While the ostensible benevolence of human instinct allows the novel to sidestep questions of injury and rape, they persist until Fanny's marriage, which delivers her to conjugal felicity. Fanny Hill presents an extreme version of the marriage plot, showing that marriage's claim to retroactively pardon harm allows it to sanction violent means. Cleland's novel implicates Pamela by demonstrating that they share a basic structure: materialist pornography, like the marriage plot, transforms injury into the impossibility thereof, forcefully restricting first-person narrative in the process.
Correctional Service of Canada Prison Libraries from 1980 to 2010
Authors: Ings Catherine , Joslin Jennifer
Published: March 2011

The last three decades have seen many developments in Canadian prison libraries. This article follows the history of the libraries in federal Correctional Service of Canada (CSC) from the 1980s to the present, concentrating on the libraries in the Pacific Region. A chronological overview of the major legislative changes, reports, and events of the last thirty years highlights the increased profile of prison libraries and their role in supporting Correctional Service of Canada's Mission and Goals. Some of these changes include the adoption in 1992 of the Corrections and Condition Release Act (CCRA) and Regulations, modifications to Commissioner's Directive 720 (2007a; under which libraries fall), and the adoption in the Pacific Region of Library Policy Guidelines. In addition to legislative and policy changes, Canadian society itself has also changed during this thirty-year period. As the face of Canada has become more diverse in age and ethnicity, as well as in social and technological expectations, so has the face of the prison population. These changes have, of course, also impacted on prison libraries. This article examines how prison libraries have met the challenges created by these societal and technological changes.
Prison Libraries in Italy
Authors: Costanzo Emanuela , Montecchi Giorgio
Published: March 2011

This article deals with prison library services in Italy, highlighting national and regional developments over the last twenty-five to thirty years. The article is divided into six parts: (1) a brief history of Italian prison libraries; (2) the structure and organization of the first institutional libraries (in Turin, Rome, Padua, Ravenna, Milan, Treviso, and Sardinia); (3) considerations by the prison administration and support from the Italian Justice Ministry; (4) the role of the university (the Association of Prison Libraries [ABC] and the new Italian Library Association [AIB] special interest group on people with special needs); (5) newer prison libraries and future projects; and (6) some user data and final conclusions.
"Prison Libraries" in Japan: The Current Situation of Access to Books and Reading in Correctional Institutions
Authors: Nakane Kenichi
Published: March 2011

This article discusses the present state of access to books and other reading materials for inmates in Japan's correctional facilities. While no professionally managed libraries are provided at these facilities—which explains why the term Prison Libraries in the title of this article is placed in quotation marks—incarcerated persons have the opportunity to obtain personal books, magazines, and newspapers through purchase or gifts. The prison administration also provides a certain number of reading materials at various locations within the institution. These materials, however, are inadequate and do not meet the needs of the offenders. The author discusses the legal framework that specifies the right of prisoners to read and obtain information, as well as the limits imposed on this access. The article contains information obtained by the author from a recent survey of seven correctional facilities. The author includes recommendations made by various advocacy groups, including the Japan Federation of Bar Associations, for improvement of the "prison library" situation and concludes with several of his own proposals to establish professionally operated prison libraries, to develop better collections, and to enhance cooperation between correctional facilities and public libraries.
An Epitaxial Si/insulator/Si Structure Prepared by Vacuum Deposition of CaF2 and Silicon
Authors: Asano T. , Ishiwara H.
Published: March 2011

Heteroepitaxial CaF2/Si and Si/CaF2/Si structures were prepared by conventional vacuum evaporation of CaF2 and silicon onto silicon substrates. The optimum conditions for obtaining good epitaxial films were investigated by changing the silicon substrate orientation, the film thickness and the substrate temperature during film deposition. From Rutherford backscattering and channelling spectroscopy it was found that CaF2 films with excellent film quality were obtained on Si(111), Si(110) and Si(100) substrates at substrate temperatures of 600– 800°C, 800°C and 500–600°C respectively. It was also found from Rutherford backscattering and channelling spectroscopy and from transmission electron microscopy that single-crystal silicon films are formed on a CaF2/Si(111) structure at a substrate temperature of 700°C. From measurements of the electrical properties of the top silicon film after the implantation of phosphorus ions at 2 ×1015 cm−2 and subsequent annealing at 750°C, an electron Hall mobility of 69cm2 V−1 s−1 was obtained.
Ion Beam Crystallography of Metal-Silicon Interfaces: Pd-Si(111)
Authors: Tromp R. , Van Loenen E. J. , Iwami M. , Smeenk R. , Saris F. W.
Published: March 2011

The application of medium energy ion scattering in combination with channelling and blocking to the study of the initial stages of palladium siuicide formation is discussed. After a brief description of the experimental arrangement and method, the effects on the Rutherford backscattering spectra of depositing small quantities of palladium on clean Si(111) are reported. The uniformity and thermal stability of thin palladium silicide films grown at room temperature were measured. Finally, channelling and blocking results were used to carry out a structural analysis of thin epitaxial Pd2Si layers.
Analysis of Surface Structural Defects by Low Energy Electron Diffraction
Authors: Welkie D. G. , Lagally M. G.
Published: March 2011

The characterization of surface structural defects by low energy electron diffraction is discussed. The identification of crystal mosaic structure, random strain, antiphase domains and steps is emphasized, and it is shown that they produce characteristic effects in the angular distribution of intensity in diffracted beams. Analytical models are summarized. They are also applicable to other surfacesensitive diffraction techniques such as reflection high energy electron diffraction and grazing angle X-ray diffraction. The quantitative analysis of these several types of defects is illustrated by measurements on the surface of an epitaxially grown Ag(111) film and on a sputter-etched and annealed GaAs(110) surface.
The Direct Observation of Atomic Surface Structure and Inclined Planar Defects in Au(111) Films
Authors: Krakow William
Published: March 2011

With a high resolution electron microscope it is possible to image directly the atomic surface lattice of vapor-deposited Au(111) films. The contrast of the surface atoms can be either black or white relative to the background which is characteristic of close-packed planes of atoms in the stacking sequence ABCABC.... An analysis of these images was performed using multislice dynamical diffraction computations of 256 × 256 = 65 536 reciprocal space points and subsequent image simulations. The effects of top and bottom surface roughness, different termination layers and the contrast compared with single-atom imaging are considered.

The identification of atomic structure detail at incoherent double-position boundaries in these (111) films was also achieved. Surface layer terminations, variations in the choice of every third matching plane and the possibility that twinning planes produce boundaries with jogs were investigated. Multislice computer programs were designed to calculate the diffraction effects from these inclined boundaries using two-dimensional fast Fourier transform and shift techniques of the projected potential. This is the first time that inclined planar defects have been analyzed in this manner.
Formation and Growth of Voids And/Or Gas Bubbles in Thin Films
Authors: Lloyd J. R. , Nakahara S.
Published: March 2011

Several recent transmission electron microscopy studies have shown that small voids and/or gas bubbles are present in various thin metallic films. The formation and growth of these voids have been studied as a function of the deposition and subsequent annealing conditions. From these studies, two conflicting views as to why these voids grow have emerged. Some investigators claim that the void growth occurs as a result of the precipitation of trapped gaseous impurities, whereas others believe that the growth is due to the annihilation of quenched-in excess vacancies at pre-existing voids. In this paper we present arguments with which we hope to resolve the present controversy.
Magnetron-Sputtered Metal-Amorphous Silicon Interfaces
Authors: Anderson W. W. , Crowley J. L. , Jonath A. D. , Macmillan H. F. , Opyd W. G. , Thornton J. A.
Published: March 2011

Large-area platinum and palladium Schottky barrier solar cells with diode quality factors approaching unity have been fabricated on magnetron-sputterdeposited hydrogenated amorphous silicon (a-Si:H). Measured optical band gaps and barrier heights are comparable with those obtained on glow-dischargeproduced a-Si:H but open-circuit voltages are lower. High surface defect densities are suggested to be responsible for the decrease in Voc.
Effects Of Grain Boundaries on the Resistivity of Cosputtered Wsi2 Films
Authors: Campbell D. R. , Mader S. , Chu W. K.
Published: March 2011

Resistivity and grain size measurements on thin films of co-sputtered WSi2 show that the resistivity in this material is dominated by grain boundary scattering. The reflection coefficient for the transport of charge carriers through the grain boundaries was determined to be approximately 0.9.
Silicide Applications In Microelectronics
Authors: Crowder Billy L.
Published: March 2011

The advent of very-large-scale integration in microelectronics has been achieved by reduction in lithographic dimensions coupled with a corresponding decrease in vertical dimensions in properly scaled device structures. This development has placed severe demands upon interconnection technology. The practice of using semiconducting regions (diffusions or polycrystalline silicon) for interconnecting devices is no longer viable because of the high resistance associated with such regions (i.e. interconnections do not “scale” properly). One solution to this problem is the use of multilevel metallization, but this requires tens of thousands of small contacts to shallow diffusions. Refractory metals such as titanium are being explored as materials which provide the necessary stable low resistance contacts suitable for integrated circuit applications. Another solution to the problem is to develop a higher conductivity material to replace or supplement polycrystalline silicon. Refractory metal disilicides have been extensively investigated for this application -both as a direct replacement for polycrystalline silicon or in a silicide/polycrystalline silicon composite (polycide). A critical review of the present status in both these areas will be presented. Emphasis will be upon our experience gained in conjunction with the development of a 1 μm silicon gate metal/oxide/ semiconductor field effect transistor technology.
The Charge State of Iron Ions Implanted Into Sapphire
Authors: Mchargue C. J. , Sklad P. S. , White C. W. , Farlow G. C. , Perez A. , Kornilios N. , Marest G.
Published: March 2011

Single crystals of α-Al2O3 were implanted with 57Fe+ at room temperature to fluences ranging from 1016 to 1017 ions/cm2. The damage in the implanted zone and the valence states and local environment of implanted ions were studied by transmission electron microscopy, Rutherford backscattering-channelling, and conversion electron Mössbauer spectroscopy. The implanted iron was distributed among the three charge states Fe2+, Fe3+, and Fe°(metallic clusters) with the relative amount of each varying with concentration of implanted iron.
High Temperature Annealing of Simox Layers Physical Mechanisms of Oxygen Segregation
Authors: Jaussaud C. , Margail J. , Stoemenos J. , Bruel M.
Published: March 2011

High temperature annealing of Simox wafers (T > 1300°C), has been proved to dramaticaly increase the quality of the SOI structure.

The heat treatment leads to a redistribution of the implanted oxygen, opposite to its concentration profile, towards the buried layer.

This paper describes from a thermodynamical point of view the SiO2 precipitates dissolution. The physical mechanisms of the oxygen migration are also discussed.
Surface Mechanical Properties and Micro-Characteristics of Ti+-Implanted Fe-Cr Alloys Depending on Cr Concentrations
Authors: Sasaki Jun , Iwaki Masaya
Published: March 2011

A study has been made on surface mechanical properties of Ti+-implanted Fe-Cr alloys with various Cr concentrations. The implantation was performed in the dose range from 1 × 1016 to 3×1017 Ti+/cm2 at the energy of 150keV. As the Cr concentration becomes lower, the friction coefficient of implanted alloys decreases, although the increase in the surface hardness is not obvious. XPS spectra show that the implantation caused the invation of carbon to form Fe-Cr-Ti-C metastable alloys containing chromium and iron carbides. It is concluded that Ti +-implantation is useful for decrease in friction of Fe-Cr alloys with the lower Cr concentration.
Carbon and Oxygen Incorporations into Surface Layers During Titanium Implantation
Authors: Fukui Y. , Hirose Y. , Iwaki M.
Published: March 2011

A study has been made of incorporations of carbon and oxygen into surfaces of fourteen kinds of specimens during titanium implantation by means of AES sputter depth profiling. The specimens used were Fe, Al, Cu, Si, Cr, Ta, Co, Ni', Mo, Ti, Au, Pt, Pd and Fe-4.5at%C, which were implanted with titanium to a fluence of 2×1017 ions/cm2 in a vacuum of ∼2×10−4 Pa at room temperature. The fourteen kinds of specimens implanted with titanium were classified into three groups according to the amounts of incorporated carbon and oxygen from a vacuum to the surfaces. The first group corresponds to Fe, Ni, Co, Al and Fe-4.5at%C, in which surfaces a large amount of carbon is incorporated. The second group corresponds to Al, Ti and Ta, in which surfaces a large amount of oxygen is incorporated. The third group corresponds to Cu, Si, Cr, Mo, Au, Pt and Pd, in which surfaces carbon and oxygen are little incorporated. In the cases of Cu, Au, Pt and Pd, little incorporations of carbon and oxygen are caused by the high sputtering yield and the less adsorptive power of the specimens.
Composition and Structure of Si3n4 Implanted with Ti AT 900°C
Authors: Singer I. L. , Vardiman R. G. , Gossett C. R.
Published: March 2011

Ti+ ions were implanted to high fluences (up to 5 × 1017 /cm2 ) into Si3N4 substrates heated to around 900°C. Composition vs depth profiles were obtained by RBS (in conjunction with RUMP analysis) and microstructures were examined by TEM. At a fluence of 4 × 1017 /cm2, the Si concentration was considerably reduced at the Ti peak depth but enriched near the surface. By 5 × 1017 /cm2, Si was nearly depleted from the implanted layer, leaving a Ti-rich nitride layer merging continuously into Si3N4. TEN detected TiN precipitates up to several pm in diameter, and coherent with Si3N4 crystallites. A Si-Ti-N ternary phase diagram is used to interpret the observed solid state reactions.
High Energy Ion Beam Annealing in Implanted CdTe
Authors: Withrow S. P. , Lusnikov A. , Jiménez-Gonz´lez- H. J. , Dresselhaus G.
Published: March 2011

The annealing effects of a high energy beam of Cu ions on implanted CdTe crystals are studied. Single crystals of CdTe have been implanted with Eu (energy 60 keV, fluence 1 × 1016 cm−2) at substrate temperatures of 25°C, and 400°C. Lattice damage introduced by the implantation process was measured by Rutherford backscattering. The samples were then implanted with high energy Cu ions (energy 3.5 MeV, fluence 0.5 × 1016 cm−2) at substrate temperatures of 25°C and 200°C. Channeling spectra from these samples indicate a reduction in the near-surface lattice damage as a result of the Cu implantation that can be unambiguously separated from the external heating of the substrate.
Electrical and Structural Study on Ion Implanted Poly(Dimethylsilylene-Co-Methylphenylsilylene)
Authors: Basheer R. A. , Hamdi A. H. , Kwor R. Y.
Published: March 2011

The effects of ion implantation on the electrical and structural properties of poly(dimethylsilylene-co-methylphenylsilylene), DMIOPS, thin films have been investigated. Ionic species of krypton, arsenic, fluorine, chlorine, and sulfur were implfgted at energies ranging from 35 to 200 key and with doses of up to 1 × 1016 ion/cm2. The conductivity of the polymer increased upon implantation reaching a maximum value of 9.6 × 10−6 (Ω cm)−1 for the case of arsenic ion at a dose of 1 × 1016 ion/cm2 and energy of 100 keV. The results showed that ion implantation induced conduction in DUMPS was primarily due to structural modifications of the material brought about by the energetic ions. Infrared analysis and Auger electron spectroscopy showed evidence for the formation of a silicon carbide-like structure upon implantation.
Nucleation in Amorphous Si:H Alloy
Authors: Koo Y. C. , Perrin A. R. , Aust K. T. , Zukotynski S.
Published: March 2011

A method of producing microcrystalline material from thin films of hydrogenated amorphous silicon was investigated. Exposure to gamma and neutron radiation, and silicon self ion implantation were used to induce nucleation in the amorphous material. According to the preliminary results, neutron irradiation represents a most promising method for promoting crystallization.
A Cross-Sectional TEM Study of the Effects of Annealing Conditions on the Regrowth of Lead-Implanted Single Crystal Calcium Titanate
Authors: Rankin J. , Boatner L. A. , White C. W. , Hobbs L. W.
Published: March 2011

The atmospheric effects of oxygen and water vapor on the epitaxial regrowth behavior of ion-implanted CaTiO3 have been studied. Cross-sectional transmission electry microsgopy (TEM) samples prepared from crystals implanted with 1(1015) Pb/cm2 at 540 KeV, were annealed at 450–650°C for 40 – 80 minutes, in environments containing different percentages of oxygen and water vapor. Regrowth was studied for implantation directions along both the <010> and <100> crystallographic directions of this orthorhombic Perovskite structure, space group Pcmn. TEM on unannealed crystals indicated the presence of an amorphous region extending approximately 190 nm in from the edge of the sample as a result of ion-implantation. Annealing produced an epitaxial regrowth of the amorphous region. The regrowth process began at the original amorphous/crystalline interface and proceeded outward to the surface of the sample. It was found that the epitaxial regrowth rate increased as the amount of water vapor in the annealing atmosphere was increased. In addition, it was observed that the amount of oxygen present during annealing did not alter the rate of recrystallization in this system.
Transient Processes at the SI-Water Interface During Pulsed Laser Irradiation
Authors: Polman A. , Sinke W. , Utitormark M. J. , Thompson Michael O.
Published: March 2011

Heat transfer processes and phase transitions at the Si-water interface during nanosecond pulsed laser irradiation were studied in real time using transient optical reflectance measurements. Measurements at two probe laser polarizations suggest that during irradiation a steam phase is formed near the Si surface. Relaxation of this phase occurs several hundred nanoseconds after solidification of the Si is completed. Acousto-optical measurements indicate that a shock wave, propagating with the sound velocity in water, is initiated near the Si-water interface.
Time Resolved Reflectivity Measurements on Pulsed Laser Irradiated Silicon Immersed in Water
Authors: Wu X. D. , Dijkkamp D. , Venkatesan T.
Published: March 2011

Time resolved reflectivity (TRR) measurements were carried out during pulsed laser irradiation of silicon immersed in water. It was found that the TRR in water was similar to that in air though the signal deteriorated after about 100 ns from the starting point of the laser for incident energy densities above 1.4 J/cm2 (unlike what is observed in air). The total melt duration in water was about 2.8 to 1.6 times less than that in air at the same absorbed energy density. It was estimated that 20 % of the absorbed energy was taken away by the water layer. For the same energy coupled into the solid the melt-in/regrowth kinetics was speeded up by the presence of the water layer at the surface by about a factor 2 consistant with the results of Polman et. a15.
Rapid Crystallization of Amorophous Gallium Produced by Laser Quenching
Authors: Fröhlingsdorf J. , Stritzker B.
Published: March 2011

Transient conductance measurements reveal the metastability of amorphous Gallium (a-Ga): Gallium can be amorphized for a certain “lifetime” at temperatures as high as 60 K, i.e. well above the crystallization temperature of 16 K.

For the first time the lower part of the C-shaped transition curve in a TTT-diagram can be measured for a pure metal. The results are in good agreement with undercooling behavior of liquid Ga-droplets.
Bilayer Structures Obtained by Pulsed Laser Quenching of Binary Systems
Authors: Baeri P. , Foti G. , Grimaldi M. G. , Priolo F. , Reitano R. , Cullis A. G. , Chew N. G.
Published: March 2011

NiSi and Ni2Si layers on silicon substrates as well as high fluence Si(As) ion implanted layers,have been rapidly melted by 30 ns Nd laser pulse irradiation.The energy density ranged between 0.4 and 1.2 J/cm2. Bilayer structures have been observed when the energy density has been chosen properly.

Buried epitaxial layers together with an amorphous or a policrystalline layer on top,have been detected by RBS and TEM measurements.
Laser-Induced Phase Transformation of Sb-Te Alloy Films for Optical Storage
Authors: Fujimori Susumu , Yagi Shogo , Yamazaki Hiroki , Funakoshi Nobuhiro
Published: March 2011

Sb-Te alloy films are developed as rewritable optical recording materials based on amorphous-crystalline phase transformations. Sb2 Te3 is shown to be the best practical phase change medium.
The Kinetics of Damage Removal Metastable Carrier Concentration Relaxation and Secondary Defect Evolution During RTA
Authors: Ii Xu , Peihsin Tsien , Zhljan Li
Published: March 2011

The kinetics of damage removal, metastable carrier concentration relaxation and secondary defect evolution in As+-implanted and rapidly annealed silicon was studied m detail. It was found that these processes are characterized by different activation energies. There is a critical temperature Tc for RTA. Only when the annealing temperature is higher than Tc, with suitable time duration can the RTA advantages be fully exloited.
Ion-Beam Mixing and Amorphization in Au/Zr Bilayers
Authors: Ding Fu-Rong , Okamoto P. R. , Rehn L. E.
Published: March 2011

Au/Zr bilayer films with inert-gas markers were produced by low energy (< 4 keV) implantation. Mass transport was measured during ion-beam mixing with 1 MeV Kr at several temperatures between 330 and 540K. Two distinct regimes of apparent Arrhenius behavior were found with activation enthalpies of 0.06 and 0.9 eV in the temperature range 330–440K and 460–540K, respectively. Microstructural changes during ion-beam mixing were studied in situ, in a high voltage electron microscope. Heterogeneous nucleation of an amorphous phase was observed during mixing. The results are compared with similar studies reported previously in Ni/Zr bilayer specimens.
The Effects of N2 and Ar as the Ambient Gas During Rapid Thermal Annealing of Tungsten Silicide
Authors: Smith Paul Martin , Thompson Michael O.
Published: March 2011

Rapid thermal annealing of amorphous tungsten silicide thin films (W0.62 Si0 38) on Si at 1100°C in Ar and N2 ambient gases was studied. All films annealed in N2 exhibited good adhesion and remained smooth with no large grain growth. Films annealed in Ar showed grain nucleation and growth from the film perimeter until a critical stress was achieved, followed by stress-assisted grain growth. The resulting growth of large columnar grains caused the films to delaminate. Removal of the surface oxide/nitride layer from the silicide prior to annealing resulted in uniform nucleation and growth over the entire film during annealing in Ar, with no stress-assisted grain growth or film delamination. No difference, however, was observed during annealing in N2. These results suggest that a surface film produced during annealing in N2 slows the nucleation and growth and consequently enhances film adhesion.
A Comparison of Different Techniques for the Rapid Thermal Annealing of Ion Implants in Silicon
Authors: Wouters D. J. , Vanhellemont J. , Avau D. , Maes H. E.
Published: March 2011

In this paper, a comparative study is presented of different techniques used for the annealing of arsenic ion implants in silicon. The used techniques are: lamp annealing using a bank of tungsten-halogen lamps, CW laser annealing and conventional furnace annealing. The annealing quality of the implanted layers is evaluated in terms of dopant activation, dopant diffusion and final extended defect states. The furnace annealing combines a good electrical dopant activation with nearly complete annihilation of the a/c dislocation loops, but substantial diffusion of the dopant profile is measured. Laser annealing gives good electrical activation with very low diffusion, but fails in removing end-of-range extended defects. Furthermore, latent electrical active defects of a donor-type are created. The tungsten halogen lamp annealing gives comparable activation and the diffusion is still lower than can be resolved by SIMS measurements, while growth and annihilation of the a/c dislocation loops is present but not yet completed. These experiments are in agreement with theoretical comparison of the different annealing techniques based on the effective (T,t) coordinates of each technique, which favours RTA processes in the high temperature - “seconds” -time range.
Rapid Thermal Processing of Thin Film Electroluminescent Display Materials
Authors: Kim D. M. , Qian F. , Solanki R. , Tuenge R. T. , King C. N.
Published: March 2011

Rapid thermal annealing of the electroluminescent phosphors ZnS:Mn, SrS:CeF3 and ZnS:SmCl3 has been examined as a function of annealing temperature (500–750°C) and time of exposure (10–120 sec.). The resulting brightness and efficiency of luminescence are correlated with the different processing conditions used. The results indicate that the brightness can be significantly improved from the value obtained with furnace annealing without causing film delamination, blistering or fatigue effect.
Modeling of Pyrolytic Laser-Assisted Chemical Vapor Deposition: Effects of Kinetics and Choice Of Substrate
Authors: Skouby D.C. , Jensen K.F.
Published: March 2011

The pyrolytlc laser-assisted deposition of metals Is modeled. A finite element approach is used to solve for temperatures and gas-phase concentrations In a transient calculation. The model accommodates the use of temperature-dependent physical properties as well as the occurrence of irregularly shaped deposits. Volcano-like deposits’ are predicted under certain conditions of gas pressure and laser intensity. The effect of using substrates with different thermal conductivities is investigated. Using adsorption-desorption kinetics such that the reaction rates have sharp maxima with respect to temperature, volcanoes of varying depths are modeled.
Buried Metal Deposition on Gallium Arsenide by Laser-Induced Thermochemical Reaction
Authors: Tokuda Jun , Takai Mikio , Gamo Kenji , Namba Susumu
Published: March 2011

Tin oxide deposition was performed by focused argon ion laser irradiation in a tin tetrachloride gas atmosphere. Etching of gallium arsenide and tin oxide deposition were observed in a single scan of a laser beam under specific conditions. The center of the irradiated area was etched and then covered with deposit. Density ratio of 0/Sn obtained from the deposit by AES measurements was about 1.4 - 1.6. Additional hydrogen gas in ambient SnCl4gas reduced both tin oxide deposition and gallium arsenide etching. Deposition, at first, occurred at the outer side of the irradiated area and gallium arsenide etching occurred at the center of it. The amount of deposit depends on beam dwell time. Additional oxygen in ambient SnCl4gas improved deposited film quality: the deposited film with additional oxygen proved to be tin dioxide, which is an conductor.
193-Nm Excimer Laser-Assisted Etching of Polysilicon Films Using Cl2
Authors: Van Nguyen Son , Fridmann S. , Rembetski J.
Published: March 2011

193-nm excimer laser-assisted etching of polysilicon was studied in the presence of CI2. Maximum etch rates of 1.25 Å/pulse were obtained for pressures of about 400 torr and fluences exceeding 400 mJ/(cm2-pulse). The etch rate increased with both fluence (100-550 mJ/(cm2-pulse)) and pressure (50-800 torr). An adsorptive etch mechanism similar to NF3 etching has been proposed, where Cl2 molecules diffuse to the surface, adsorb, and then react after absorbing laser radiation. This is consistent with photon and molecular flux considerations and the availability of reaction sites. Thermal effects where Cl2 molecules decompose to Cl atoms on “hot” polysilicon surfaces may assist this process, and appear to dominate under conditions of lower pressure (<400 torr) and higher fluence. Etching caused by the gas phase formation of Cl atoms is minimal due to the low Cl2 absorption cross section at 193 nm.

Simple projection etching results showed that micron lines can be etched in polysilicon by use of this chemistry.
Thermal and Photon-Induced Chemistry of Adsorbed Cadmium and Tellurium Alkyls
Authors: Stinespring C.D. , Freedman A.
Published: March 2011

Experimental studies of the thermal and photon-induced surface chemistry of two organometallic molecules, dimethyl cadmium and dimethyl tellurium, are reported for a variety of surfaces including Au, GaAs, Si, and SiO£. These studies followed ultrahigh vacuum compatible procedures and used x-ray photoelectron spectroscopy to characterize the chemical state and coverage of the adspecies formed at 295 K. The results showed considerable diversity in the thermal surface chemistry of the systems investigated. Depending on the substrate, physisorption and dissociative chemisorption to yield monomethyl and metal adspecies were observed. Irradiation of the physisorbed adspecies with 193 nm UV photons led to single photon photodecomposition and limited photodesorption. Similar irradiation of the monomethyl-adspecies caused only limited photodesorption.
Thin Films of Oxygen-Deficient Perovskite Superconductors by Laser Ablation
Authors: Bohandy Joseph , Adrian F. J. , Moorjani K. , Green W. J. , Kim B. F.
Published: March 2011

Thin films of the new class of high temperature superconducting perov-skites have been prepared by laser ablation of t,he bulk materials with a pulsed, excimer laser operating at 193 nm. The films were deposited on room temperature substrates without post-deposition processing. The existence of superconducting regions in the inhomogeneous films was established by a novel microwave method which uses a slightly modified electron spin resonance spectrometer.
Laser Photochemical Growth of Amorphous Silicon at Low Temperatures and Comparison with Thermal Chemical Vapor Deposition
Authors: Eres D. , Lowndes D. H. , Geohegan D. B. , Mashburn D. N.
Published: March 2011

Pulsed ArF (193 nm) excimer laser radiation has been used to dissociate disilane (Si2H6), resulting in photochemically controlled deposition of amorphous Si thin films. A high stability HeNe (6328 Å) laser was used for precise in situ monitoring of film deposition rates, under varying deposition conditions. A helium window purge nearly eliminated Si film deposition on the chamber windows. With the excimer laser beam parallel to the substrate, deposition of amorphous Si can be controlled entirely by the photon fluence (negligible background thermal growth) at temperatures from room temperature up to ~400°C. Reasonable photolytic deposition rates (>1 A/sec) are combined with "digital" control of film thickness (>0.02 A/laser pulse). Activation energies of 1.50 (±0.1) eV and 0.09 (±0.02) eV were found for pyrolytic and photolytic deposition, respectively.
A Chemical Study of Photo-CVD of Silicon Nitride in Mercury-Sensitized Reactions Between Silane and Ammonia
Authors: Wu Ching-Hsong
Published: March 2011

A photochemical system of mercury-sensitized reactions between silane and ammonia was studied to elucidate the gas-phase chemical processes involved in photo-CVD of silicon nitride. Several transient intermediates were detected and identified as silylated amines by the mass spectrometric isotope labeling method. These compounds containing both Si and N atoms appeared to be the precursors of silicon nitride. The chemical characteristics of silylated amines were studied under different experimental conditions. The reactivity and possible reaction paths for the formation of silylamine are discussed.
Characterization of Photo-Cvd Silicon Oxide
Authors: Padmanabhan R. , Miller B. J. , Saha N. C.
Published: March 2011

A photochemical vapor deposition technique was used to deposit silicon oxide films. A range of film properties was produced through changes in the process conditions. Refractive index, indicative of film composition, varied from 1.5 to 2.0, corresponding to oxygen rich and silicon rich conditions, respectively. Etch rate in buffered HF was a strong function of the refractive index, with higher index of refraction yielding lower rates. Film stress was tensile and the magnitude of the stress was again related to the index of refraction. Other properties that were evaluated included pinhole density and adhesion to Si. All the properties were directly relatable to the basic film composition.

X-ray photo electron and Auger electron spectroscopy were used to characterize the composition of these films. The Si 2p photoelectron and the Si KLL Auger electron spectra were broad for higher refractive index films and upon deconvolution indicated the presence of different silicon containing species, the natures of which depended upon the actual index of refraction. For stoichiometric films, the predominant constituent was SiO2 and for non-stoichiometric films, varying amounts of Si2O, SiO, Si2O3 and SiO2 were all present.
Resonance Raman Spectra of Halogen Molecules Adsorbed on Metal Substrates
Authors: Matsushima Takeo , Kawasaki Masahiro , Sato Hiroyasu
Published: March 2011

Resonance Raman spectroscopy was used to monitor the adsorption of halogen molecules (bromine and iodine) on metal substrates. The Raman bands of chemisorbed, physisorbed and crystalline species were found in the spectra. In the case of bromine, when the temperature was raised from 77 K, the band associated with the chemisorbed species increased in intensity with the concomitant decrease in intensity of the band of crystalline species. A similar increase in the band intensity of the chemisorbed species at the sacrifice of that of the crystalline species was found on continued laser irradiation. The saturation of the band intensity of chemisorbed species was found in the latter case, however. The continued evaporation of bromine vapor onto the substrate surface at 77 K with the simultaneous monitoring of the layer thickness revealed that the initial deposit of bromine onto the substrate did not lead to the chemisorbed species. The accumulation of the crystalline species occurred in its stead. The occurrence of the molecular transfer process from the crystalline species into the chemisorbed species was suggested. The Raman excitation profile showed that bromine molecules adsorbed on a substrate do not dissociate in the wavelength range studied (16000-22000 cm-1). The excitation profile is to be given by Albrecht's A term and roughly corresponds to the absorption spectrum of thin film of bromine on the substrate, which is very difficult to obtain directly.
Maskless Etching of SiO2 by Ion Beam Assisted Etching Technique
Authors: Xu Zheng , Gamo Kenji , Namba Susumu
Published: March 2011

Characteristics of ion beam assisted etching (IBAE) for SiO2 have been investigated to reveal'a possibility for maskless etching using focused ion beams. The ion beam assisted etching was done by bombarding 50 keV unfocused ion beams in XeF2 atmosphere and effect of various etching parameter on etching characteristics have been investigated. These are the effects of XeF2 gas pressure, bombarding ion species, bombarding angle and H2 addition, etc. Significant enhancements up to 100 times larger than physical sputtering were achieved. The selectivity of SiO2 to Si could be tailored to specific requirements from 0.1 to 6 by changing the gas mixing ratio. The etching rate was approximately proportional to the energy deposition rate bombarded by ion beam on surface. Carbon contamination on surface after etching were improved by the introduction of XeF2 gas.
The Dopamt Diffusion Mechanism in Eicimer Laser Induced Molten Silicon
Authors: Sameshima Toshiyuki , Usui Setsuo
Published: March 2011

We have calculated the degree of dopant diffusion which occurs during non-equilibrium incorporation of boron from the silicon surface into the molten silicon induced by a pulsed excimer laser. When a high-power lascr causes the melt front to proceed into the substrate faster than 8 m/s, p+ -doped regions are formed near the surface of the molten silicon because boron atoms cannot diffuse sufficiently fast for the junction depth to reach the maximum melt depth.