bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transient Pronounced Density Variation in Amorphous Ice Structures
Authors: Koza M. 
Published: September 2009

Abstract
The structural transformation of different high-density amorphous (HDA) ice modifications into the low-density amorphous (LDA) ice is studied by small-angle neutron scattering (SANS) techniques. All experiments have been performed at stationary conditions allowing to collect detailed information not only on the SANS formfactor but also on its time evolution and, hence, the kinetics governing the transformation process. A parametrization of the SANS formfactor by a superposition of the Debye-Bueche formfactor, characterizing a non-particulate two phase mixture, and a Porod-limit scattering formfactor is carried out successfully. The Porod-limit scattering indicates the presence of sharp interfaces and surfaces present in the sample material. Interpreting this signal as due to a grainy consistency of the amorphous samples grain sizes of the order of at least some micrometers can be approximated. The Debye-Bueche ansatz accounts for the formation of a transient pronounced signal on mesoscopic length scales. Its analysis results in an average domain size of 12–16 Å characterizing a hypothetical two phase mixture in its state of strongest intermixture, i.e., strongest heterogeneity. Interpretation of the Debye-Bueche formfactor by the Porod invariant results in a sample contrast that is by a factor of about 4 smaller than a hypothetical first-order transition between any modification of HDA and LDA. This statement is valid for an unstrained two-phase system separated by sharp interfaces. A detailed discussion is given which tries to set the present results into a more realistic context.
Low Temperature Solution-Based Fabrications of Metal Oxide Semiconductor Films by Mechanical Sintering
Authors: Yoshida Manabu , Suemori Kouji , Uemura Sei , Hoshino Satoshi , Takada Noriyuki , Kodzasa Takehito , Kamata Toshihide 
Published: September 2009

ABSTRACTVarious flexible electronic devices have been intensively studied and developed in this decade. Most of consumers expect to obtain these flexible electronic devices in the next decade. The spread of flexible electronic devices depends on the process costs and material costs. Today prices of materials and energy sources are continuously increasing. Therefore, using of expensive materials and wasteful processes for fabricating electronic devices should be reconsidered. Printing techniques, a representative solution process, are inexpensive and very effective for mass production of electronic devices. We have developed a low-temperature process for fabricating flexible printed patterns of metals and semiconductors by using relatively inexpensive commercial pastes. A characteristic of our process is to utilize mechanical energies for sintering particles contained in pastes. In our process, the precise three-dimensional pressure control brings about the improvement of electrical properties in the printed patterns, the preservation of pattern accuracy and the mechanical durability of the printed patterns. In our experiment, we have already fabricated very low resistivity metal patterns (about 6×10−6Ω·cm) at ca.120°C without using any kinds of nano-particle paste, and also fabricated metal oxide semiconductor patterns.
Ultimately Low Schottky Barrier Height at NiSi/Si Junction by Sulfur Implantation after Silicidation for Aggressive Scaling of MOSFETs
Authors: Yang Yen-Chu , Nishi Yoshifumi , Kinoshita Atsuhiro 
Published: September 2009

AbstractParasitic resistance, particularly source/drain contact resistance becomes one of the most serious problems to extend MOSFET scaling recently. Nickel silicide (NiSi), with advantages of low resistivity and high scalability, has been chosen as the material for source/drain formation. However, its Schottky barrier height (SBH) of 0.65eV for electrons is so high that it would block electrons from tunneling, therefore becomes an obstacle to further reduce the contact resistance, which is necessary to achieve the future scaling. Among several solutions, high concentration impurity-segregation layers have been introduced at NiSi/Si interfaces to reduce SBH of MS-MOSFETs. Sulfur (S) has been considered to be an efficient material for the segregation-layer to reduce SBH owing to Fermi-level pinning effect. Previous studies have investigated segregation by implanting S before NiSi formation. Because of the high diffusivity of S in Si, S profile becomes broad during silicidation process, which leads to loss of S concentration at the interface. Moreover, S ions spread into the substrate and channel region generate deep impurity levels that induce junction leakage and off leakage, resulting in device performance degradation. In this paper, S implantation after Ni silicidation is proposed to suppress S diffusion because NiSi is expected to be an efficient barrier for S diffusion. In addition, NiSi/Si interface can serve as a potential energetic valley which may trap S during thermal treatment after implantation. In this work, S was implanted into NiSi/n-Si diodes at the energy of 10keV with dose of 5�1014 and 1015 cm-3 after NiSi is formed. The projection range of S in NiSi is about 6nm, while thickness of NiSi is 16nm. Some devices were annealed at 300C and 450C. The I-V characteristics show that SBH is sufficiently reduced as the annealing temperature becomes higher, and it reaches as low as 3.4meV for 450C annealing. SBH of 3.4meV is much lower than the previously reported value of 70meV for which S was implanted before silicidation. The SIMS analysis result also proves the S profile is much sharper than having S-implantation before Ni silicidation, which supports our hypothesis that S diffusion is suppressed through our process and avoid the loss of S concentration at the interface. Moreover, despite the worry that S-implantation might damage the NiSi/Si interface morphology, cross sectional TEM images show that the interfacial flatness is completely the same as that of non-implanted NiSi/Si, indicating that no degradation occurs by S implantation. In summary, S-implantation after NiSi formation, which provides ultimately low SBH at NiSi/Si interface, is a promising technique to realize ultra-low parasitic resistance source/drain for future LSI beyond 16nm generation.
Experimental Evidence of Long-Range Point Defect-Phosphorous Pair Diffusion in Silicon
Authors: Nayfeh Ammar , Koldyaev Viktor 
Published: September 2009

AbstractPoint Defect (PD) mediated diffusion of phosphorous in silicon is studied in order to address the long standing open problem of PD-Dopant pair lifetime. A novel experimental method is suggested to increase PD-P pair lifetime for better observability and experimental resolution. In the experiment, phosphorous is implanted, followed by low temperature poly-Si deposition with in-situ doped phosphorous. The P profile shows, after low temperature (<650°C) in-situ phosphorous doped poly-Si deposition, an exponential dependence of two orders of magnitude for a significant depth scale. This indicates that the PD-P pairs survive long-range diffusion before dissociating in the Si lattice. As a result, the lifetime of PD-P pair was extracted and this provides a physical basis for TCAD simulation at the atomic scale.
Interface and Electrical Properties of Atomic-layer-deposited HfAlO Gate Dielectric for N-channel GaAs MOSFETs
Authors: Suri Rahul , Lichtenwalner Daniel J , Misra Veena 
Published: September 2009

AbstractThe interface and electrical properties of HfAlO dielectric formed by atomic layer deposition (ALD) on sulfur-passivated GaAs were investigated. X-ray photoelectron spectroscopy (XPS) revealed the absence of arsenic oxides at the HfAlO/GaAs interface after dielectric growth and post-deposition annealing at 500 °C. A minimal increase in the amount of gallium oxides at the interface was detected between the as-deposited and annealed conditions highlighting the effectiveness of HfAlO in suppressing gallium oxide formation. An equivalent oxide thickness (EOT) of ∼ 2 nm has been achieved with a gate leakage current density of less than 10-4 A/cm2. These results testify a good dielectric interface with minimal interfacial oxides and open up potential for further investigation of HfAlO/GaAs gate stack properties to determine its viability for n-channel MOSFETs.
Defects in HfO2 Based Dielectric Gate Stacks
Authors: Lenahan Patrick M. , Ryan Jason T. , Cochrane Corey J. , Conley John F. 
Published: September 2009

AbstractWe report on both conventional electron paramagnetic resonance (EPR) measurements of fully processed HfO2 based dielectric films on silicon and on electrically detected magnetic resonance (EDMR) measurements of fully processed HfO2 based MOSFETs. The magnetic resonance measurements indicate the presence of oxygen vacancy and oxygen interstitial defects within the HfO2 and oxygen deficient silicons in the interfacial layer. The EDMR results also indicate the generation of at least two defects when HfO2 based transistors are subjected to significant negative bias at modest temperature. Our results indicate generation of multiple interface/near interface defects, likely involving coupling with nearby hafnium atoms.
Attempt to Grow α-Rhombohedral Boron Crystals in Copper Solvent
Authors: Gao Wei , Whiteley Clinton , Zhang Yi , Plummer Jack , Edgar James , Gong Yinyan , Kuball Martin 
Published: September 2009

AbstractAn excellent material for thermal neutron detectors is α-rhombohedral boron, due to the large neutron capture cross section of 10B, high hole mobility and ability to self-heal from radiation damage, to date, little work has been done on the crystal growth of α-rhombohedral boron. In this investigation, we attempt to grow α-rhombohedral boron by the solution growth method, employing copper as solvent. Well-faceted transparent red crystals several hundreds of microns in size have been made. Elemental analysis of the crystals detected boron, with negligible amounts of copper, suggesting that copper is a promising solvent for the crystal growth of α-rhombohedral boron crystal.
Effect of oxygen on nanoscale indentation-induced phase transformations in amorphous silicon
Authors: Ruffell Simon , Williams Jim 
Published: September 2009

AbstractIon-implantation has been used to introduce oxygen concentration-depth profiles into nominally oxygen-free amorphous silicon (a-Si). The effect of O concentrations in excess of 1018 cm−3 on the formation of high pressure crystalline phases (Si-III and Si-XII) during indentation unloading has been studied. By examination of unloading curves and post-indent Raman micro-spectroscopy O is found to inhibit the so-called pop-out event during unloading and, therefore, the formation of the crystalline phases. Furthermore, at high O concentrations (> 1021 cm−3) the formation of these phases is reduced significantly such that under indentation conditions used here the probability of forming the phases is reduced to almost zero. We suggest that the bonding of O with Si reduces the formation of Si-III/XII during unloading through a similar mechanism to that of oxygen-retarded solid phase crystallization of a-Si.
In utero meconium passage in fetuses and newborns with myelomeningocele
Authors: Danzer Enrico , Ernst Linda M. , Rintoul Natalie E. , Johnson Mark P. , Adzick N. Scott , Flake Alan W. 
Published: September 2009

Object
The authors retrospectively investigated whether midgestational fetal myelomeningocele (fMMC) repair alters intrauterine meconium exposure.

Methods
Prior to the National Institutes of Health Management of Myelomeningocele Study, 54 fetuses underwent fMMC repair at the authors' institution. Forty-six fMMC sacs were available for pathological examination and 53 MMC sacs from postnatally repaired MMCs (pMMCs) were available for comparison. The presence and distribution of meconium were blindly evaluated using a grading system defined as follows: absent (no meconium present), mild (< 10 meconium-positive histiocytes [MPHs]/hpf), moderate (10–25 MPHs/hpf), and severe (> 25 MPHs/hpf). Hall's bile stain was used to confirm meconium and Prussian blue and Fontana Masson stains to exclude hemosiderin and melanin, respectively.

Results
Compared to pMMCs (79%), meconium histiocytosis was less prevalent in fMMC sacs (57%; p = 0.017). Meconium staining was completely absent in 43% of the fMMC sacs. Mild meconium histiocytosis was found in 35% fMMC and 61% pMMC sacs (p = 0.035). There was no statistical difference between groups with moderate and severe meconium histiocytosis.

Conclusions
Meconium passage in MMCs can occur early in fetal life. Fetal MMC repair may reduce the duration of meconium exposure, thereby potentially limiting the toxic injury to the vulnerable neural elements.
Computed tomography morphometric analysis for axial and subaxial translaminar screw placement in the pediatric cervical spine
Authors: Chern Joshua J. , Chamoun Roukoz B. , Whitehead William E. , Curry Daniel J. , Luerssen Thomas G. , Jea Andrew 
Published: September 2009

Object
The management of upper cervical spinal instability in children continues to represent a technical challenge. Traditionally, a number of wiring techniques followed by halo orthosis have been applied; however, they have been associated with a high rate of nonunion and poor tolerance for the halo. Alternatively, C1–2 transarticular screws and C-2 pars/pedicle screws allow more rigid fixation, but their placement is technically demanding and associated with vertebral artery injuries. Recently, C-2 translaminar screws have been added to the armamentarium of the pediatric spine surgeon as a technically simple and biomechanically efficient means of fixation. However, the use of subaxial translaminar screws have not been described in the general pediatric population. There are no published data that describe the anatomical considerations and potential limitations of this technique in the pediatric population.

Methods
The cervical vertebrae of 69 pediatric patients were studied on CT scans. Laminar height and thickness were measured. Statistical analysis was performed using unpaired Student t-tests (p < 0.05) and linear regression analysis.

Results
The mean laminar heights at C-2, C-3, C-4, C-5, C-6, and C-7, respectively, were 9.76 ± 2.22 mm, 8.22 ± 2.24 mm, 8.09 ± 2.38 mm, 8.51 ± 2.34 mm, 9.30 ± 2.54 mm, and 11.65 ± 2.65 mm. Mean laminar thickness at C-2, C-3, C-4, C-5, C-6, and C-7, respectively, were 5.07 ± 1.07 mm, 2.67 ± 0.79 mm, 2.18 ± 0.73 mm, 2.04 ± 0.60 mm, 2.52 ± 0.66 mm, and 3.84 ± 0.96 mm. In 50.7% of C-2 laminae, the anatomy could accept at least 1 translaminar screw (laminar thickness ≥ 4 mm).

Conclusions
Overall, the anatomy in 30.4% of patients younger than 16 years old could accept bilateral C-2 translaminar screws. However, the anatomy of the subaxial cervical spine only rarely could accept translaminar screws. This study establishes anatomical guidelines to allow for accurate and safe screw selection and insertion. Preoperative planning with thin-cut CT and sagittal reconstruction is essential for safe screw placement using this technique.
Indolent dorsal midbrain tumor: new findings based on positron emission tomography
Authors: Yamaguchi Shigeru , Terasaka Shunsuke , Kobayashi Hiroyuki , Shiga Tohru , Usui Reiko , Hirata Kenji , Kubota Kanako , Murata Junichi , Iwasaki Yoshinobu 
Published: September 2009

Object
Intrinsic tumors arising in the dorsal midbrain cause obstructive hydrocephalus and have an indolent clinical course. Positron emission tomography (PET) with fluorine-18–labeled fluorodeoxyglucose (FDG) and l- [methyl-11C]methionine (MET) was used to evaluate the biological behaviors of dorsal midbrain tumors.

Methods
The authors report on 4 patients (3 males and 1 female) with dorsal midbrain tumors who presented with obstructive hydrocephalus. A diagnosis was made with MR imaging in each patient. To manage the hydrocephalus, endoscopic third ventriculostomy was performed in all cases. The patients did not undergo any other surgical procedures except endoscopic biopsy procedure, chemotherapy, or radiation therapy. The patients in 3 cases underwent FDG- and MET-PET within 6 months of CSF-diverting procedures, and the patient in 1 case underwent PET 10 years after the procedure.

Results
After the CSF-diverting procedure, clinical symptoms resolved or improved in all patients. Gliosis or glial proliferation was diagnosed in 1 patient, and possible low-grade glioma in 2 patients. Although all tumors appeared hyperintense on T2-weighted MR images, their appearance on T1-weighted images was variable (iso- and/or hypointense), and partial lesion enhancement was observed on images from 2 patients. On the other hand, the PET features of these lesions were almost identical, and the scans did not show a high uptake of FDG and MET compared with the cortical uptake in a normal brain. The mean tumor tissue/normal tissue ratio of FDG uptake was 0.65, and that of MET was 0.99.

Conclusions
Positron emission tomography findings suggested that the indolent dorsal midbrain lesion had nontumorous characteristics, thus supporting a good prognosis. Positron emission tomography studies may be more informative and predictive of the biological behavior of dorsal midbrain tumors than a biopsy procedure.
Spinal congenital dermal sinus with dual ostia
Authors: Lee Chang Sub , Phi Ji Hoon , Kim Seung-Ki , Cho Byung-Kyu , Wang Kyu-Chang 
Published: September 2009

Object
Congenital dermal sinus (CDS) usually develops in the midline of the body as a single tract. To date, only a few patients with multiple CDS tracts and ostia have been reported. The authors analyzed the clinical features of patients with spinal CDS and multiple ostia and proposed a novel hypothesis for the pathogenesis of the atypical CDS.

Methods
Five patients with spinal CDS and multiple ostia were included. The clinical, radiological, and operative features of these patients were reviewed retrospectively.

Results
Three patients demonstrated bilateral paramedian ostia at the same or a very similar spinal level. One patient showed a paramedian and a midline ostium. One patient had 2 unilateral paramedian ostia at different spinal levels. The layers of the internal ending of CDS tracts were diverse. Complete removal of the tracts was possible in all patients. Two patients had dermoid tumors. All patients had an associated anomaly, such as a lumbosacral lipoma or the Currarino triad. The authors propose a “zipping error” hypothesis for the formation of dual ostia located at the spinal level of primary neurulation. An associated anomaly such as a lumbosacral lipoma may contribute to the formation of dual ostia.

Conclusions
Unilateral or bilateral dual ostia may be present in patients with CDS, especially when an associated anomaly is present. The atypical CDS may develop from aberrant neural tube closure.
A model for neurosurgical humanitarian aid based on 12 years of medical trips to South and Central America
Authors: Mainthia Rajshri , Tye Gary W. , Shapiro Jay , Doppenberg Egon M. R. , Ward John D. 
Published: September 2009

The pediatric neurosurgical mission trips led by physicians at Virginia Commonwealth University (VCU) Health Systems began in 1996 with the formation of Medical Outreach to Children, founded by 1 of the authors (J.D.W.) after a visit to Guatemala. Since then, 19 surgical trips to 4 different countries in Central and South America have been coordinated from 1996 to 2008.
This humanitarian work serves a number of purposes. First and foremost, it provides children with access to surgical care that they would otherwise not receive, thereby significantly improving their quality of life. Second, the visiting surgical team participates in the education of local physicians, parents, and caregivers to help improve the healthcare provided to the children. Last, the team works to promote sustainable global health solutions in the countries it travels to by generating a forum for clinical and public health research discourse.
Thus far, a total of 414 children have undergone 463 operations, including 154 initial shunt surgeries, 110 myelomeningocele repairs, 39 lipoma resections, 33 tethered cord releases, 18 shunt revisions, 16 encephalocele repairs, 9 lipomyelomeningocele repairs, and 7 diastematomyelia repairs. The complication rate has been 5–8%, and the team has obtained reliable follow-up in ~ 77% of patients. A correlation was found between an increase in the number of trained neurosurgeons in the host countries and a decrease in the average age of patients treated by the visiting surgical team over time. It is also hypothesized that a decrease in the percentage of myelomeningocele repairs performed by the surgical team (as a fraction of total cases between 1996 and 2006) correlates to an increase in the number of local neurosurgeons able to treat common neural tube defects in patients of younger ages. Such analysis can be used by visiting surgical teams to assess the changing healthcare needs in a particular host country.
Surgical outcome of tuberculous meningitis hydrocephalus treated by endoscopic third ventriculostomy: prognostic factors and postoperative neuroimaging for functional assessment of ventriculostomy
Authors: Chugh Ashish , Husain Mazhar , Gupta Rakesh K. , Ojha Bal K. , Chandra Anil , Rastogi Manu 
Published: September 2009

Object
Endoscopic third ventriculostomy (ETV) is increasingly being used as an alternative treatment for post–tuberculous meningitis (TBM) hydrocephalus. The aim of this study was to affirm the role of ETV in patients with TBM hydrocephalus and also to study the usefulness of cine phase-contrast MR imaging (cine MR imaging) for functional assessment of the ETV stoma. An additional goal was to identify factors that influence the outcome of ETV, so as to define patients with TBM hydrocephalus in whom ETV is warranted.

Methods
Twenty-six patients with TBM hydrocephalus treated with ETV were evaluated clinically and with cine MR imaging postoperatively. The duration of follow-up ranged from 1 to 15 months. The authors evaluated flow void changes in the floor of the third ventricle and analyzed parameters from the preoperative data, which they then used as a basis for comparison between endoscopically successful and endoscopically unsuccessful cases.

Results
The overall success rate of ETV in TBM hydrocephalus was 73.1% in this case series. Cine MR imaging showed a sensitivity of 94.73% and specificity of 71.42% for the functional assessment of third ventriculostomy in these patients, with the efficacy being maintained during follow-up. The outcome of ETV showed a statistically significant correlation with the stage of illness and presence of intraoperative cisternal exudates. Although duration of symptoms and duration of preoperative antituberculous therapy (ATT) appeared to influence the outcome, their correlation with outcome was not statistically significant.

Conclusions
Endoscopic third ventriculostomy should be considered as the first surgical option for CSF diversion (that is, before shunt surgery) in patients with TBM hydrocephalus. Cine MR imaging is a highly effective noninvasive tool for the postoperative functional assessment of stomata. Patients who presented with a history of longer duration and those who were administered preoperative ATT for a longer period had a better outcome of endoscopic treatment. Outcome was poorer in patients who presented with higher stages of illness and in those in whom cisternal exudates were observed intraoperatively.