bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms of Dipolar Ortho/Para-H2O Conversion in Ice
Authors: Buntkowsky Gerd , Limbach Hans-Heinrich , Walaszek B. , Adamczyk A. , Xu Y. , Breitzke H. , Schweitzer A. , Gutmann T. , Wächtler M. , Amadeu N. , Tietze D. , Chaudret Bruno 
Published: September 2008

Abstract
In this paper a possible explanation for an unexpected ortho/para-water ratio in the gas clouds of comets is given. The description is based on the quantum-mechanical density matrix formalism and the spin temperature concept. Only the nuclear spin system is treated quantum-mechanically. Employing the model of a four spin system, created by two nearest neighbour water molecules, spin eigenstates and their dynamics under the influence of their mutual dipolar interactions are studied. It is shown that a fast conversion between ortho- and para-states occurs on a msec time scale, caused by the intermolecular homonuclear magnetic dipolar interaction. Moreover the spin eigenstates of water in an ice crystal are determined by magnetic dipolar interactions and are not given by normal ortho- and para-H2O states of gaseous water. As a result of this the spin temperature of gaseous water evaporated from ice depends strongly on its evaporation history and the ortho/para-ratio of water molecules are only an indirect measure of the temperature of ice crystals from where they descend. This result could explain the unexpected experimentally observed ortho/para-ratios in the clouds of comets.
IFATS Collection: Human Adipose-Derived Stem Cells Seeded on a Silk Fibroin-Chitosan Scaffold Enhance Wound Repair in a Murine Soft Tissue Injury Model
Authors: Altman Andrew M. , Yan Yasheng , Matthias Nadine , Bai Xiaowen , Rios Carmen , Mathur Anshu B. , Song Yao-Hua , Alt Eckhard U. 
Published: September 2008

Abstract
Soft tissue loss presents an ongoing challenge in reconstructive surgery. Local stem cell application has recently been suggested as a possible novel therapy. In the present study we evaluated the potential of a silk fibroin-chitosan (SFCS) scaffold serving as a delivery vehicle for human adipose-derived stem cells (ASCs) in a murine soft tissue injury model. Green fluorescent protein (GFP)-labeled ASCs were seeded on SFCS scaffolds at a density of 1 × 105 ASCs per cm2 for 48 hours and then suture-inlaid to a 6-mm, full-thickness skin defect in 6-week-old male athymic mice. Wound healing was tracked for 2 weeks by planimetry. Histology was evaluated at 2 and 4 weeks. Our data show that the extent of wound closure was significantly enhanced in the ASC-SFCS group versus SFCS and no-graft controls at postoperative day 8 (90% ± 3% closure vs. 75% ± 11% and 55% ± 17%, respectively). Microvessel density at wound bed biopsy sites from 2 weeks postoperative was significantly higher in the ASC-SFCS group versus SFCS alone (7.5 ± 1.1 vs. 5.1 ± 1.0 vessels per high-power field). Engrafted stem cells were positive for the fibroblastic marker heat shock protein 47, smooth muscle actin, and von Willebrand factor at both 2 and 4 weeks. GFP-positive stem cells were also found to differentiate into epidermal epithelial cells at 4 weeks postoperative. In conclusion, human adipose-derived stem cells seeded on a silk fibroin-chitosan scaffold enhance wound healing and show differentiation into fibrovascular, endothelial, and epithelial components of restored tissue.
A Sox1 to Pax6 Switch Drives Neuroectoderm to Radial Glia Progression During Differentiation of Mouse Embryonic Stem Cells
Authors: Suter David M. , Tirefort Diderik , Julien Stephanie , Krause Karl-Heinz 
Published: September 2008

Abstract
The transcription factors Sox1 and Pax6 are expressed sequentially during early mouse embryonic neurogenesis. Sox1 expression starts upon formation of neuroectoderm, whereas Pax6 is subsequently expressed in radial glial cells, the latter giving rise to most neurons of the cerebral cortex. Here we used mouse embryonic stem (ES) cells to study the role of Sox1 and Pax6 in regulating differentiation of neural progenitors. For this purpose, we investigated the effect of overexpression and knockdown of Sox1 and Pax6, using three differentiation protocols. We show that (a) expression of Sox1 or Pax6 in uncommitted ES cells favored neuroectodermal lineage choice; (b) continuous Sox1 expression maintained cells at the neuroepithelial stage and prevented expression of Pax6 and other radial glial cell markers; (c) Sox1 knockdown facilitated exit from the progenitor stage, whereas Pax6 knockdown decreased formation of radial glia; (d) forced Pax6 expression in neuroepithelial cells triggered their differentiation into radial glia and neurons; and (e) Pax6 expression induced cell migration, a feature typical of radial glia-derived early neurons. We conclude that Sox1 enhances neuroectodermal commitment and maintenance but blocks further differentiation. In contrast, Pax6 is involved in the progression of neuroectoderm toward radial glia.
Analysis of Extracellular Signal-Regulated Kinase 2 Function in Neural Stem/Progenitor Cells via Nervous System-Specific Gene Disruption
Authors: Imamura Osamu , Satoh Yasushi , Endo Shogo , Takishima Kunio 
Published: September 2008

AbstractExtracellular signal-regulated kinase 2 (ERK2) is involved in a variety of cell fate decisions during development, but its exact role in this process remains to be determined. To specifically focus on the role of ERK2 in the brain, and to avoid early lethalities, we used a conditional gene-targeting approach to preferentially inactivate Erk2 in the embryonic mouse brain. The resulting mutant mice were viable and were relatively normal in overall appearance. However, the loss of Erk2 resulted in a diminished proliferation of neural stem cells in the embryonic ventricular zone (VZ), although the survival and differentiation of these cells was unaffected. The multipotent neural progenitor cells (NPCs) isolated from ERK2-deficient brains also showed impaired proliferation, reduced self-renewal ability, and increased apoptosis. By neurosphere differentiation analysis we further observed that lineage-restricted glial progenitors were increased in ERK2-deficient mice. The decline in the self-renewal ability and multipotency of NPCs resulting from the loss of ERK2 was found to be caused at least in part by upregulation of the JAK-STAT signaling pathway and reduced G1/S cell cycle progression. Furthermore, by global expression analysis we found that neural stem cell markers, including Tenascin C NR2E1 (Tlx), and Lgals1 (Galectin-1), were significantly downregulated, whereas several glial lineage markers were upregulated in neurospheres derived from ERK2-deficient mice. Our results thus suggest that ERK2 is required both for the proliferation of neural stem cells in the VZ during embryonic development and in the maintenance of NPC multipotency by suppressing the commitment of these cells to a glial lineage.Disclosure of potential conflicts of interest is found at the end of this article.
1,4,5-Inositol Trisphosphate-Operated Intracellular Ca2+ Stores and Angiotensin-II/Endothelin-1 Signaling Pathway Are Functional in Human Embryonic Stem Cell-Derived Cardiomyocytes
Authors: Sedan Oshra , Dolnikov Katya , Zeevi-Levin Naama , Leibovich Noa , Amit Michal , Itskovitz-Eldor Joseph , Binah Ofer 
Published: September 2008

Abstract
On the basis of previous findings suggesting that in human embryonic stem cell-derived cardiomyocytes (hESC-CM) the sarcoplasmic reticulum Ca2+-induced release of calcium machinery is either absent or immature, in the present study we tested the hypothesis that hESC-CM contain fully functional 1,4,5-inositol trisphosphate (1,4,5-IP3)-operated intracellular Ca2+ ([Ca2+]i) stores that can be mobilized upon appropriate physiological stimuli. To test this hypothesis we investigated the effects of angiotensin-II (AT-II) and endothelin-1 (ET-1), which activate the 1,4,5-IP3 pathway, on [Ca2+]i transients and contractions in beating clusters of hESC-CM. Our major findings were that in paced hESC-CM both AT-II and ET-1 (10−9 to 10−7 M) increased the contraction amplitude and the maximal rates of contraction and relaxation. In addition, AT-II (10−9 to 10−7 M) increased the [Ca2+]i transient amplitude. The involvement of 1,4,5-IP3-dependent intracellular Ca2+ release in the inotropic effect of AT-II was supported by the findings that (a) hESC-CM express AT-II, ET-1, and 1,4,5-IP3 receptors determined by immunofluorescence staining, and (b) the effects of AT-II were blocked by 2 μM 2-aminoethoxyphenyl borate (a 1,4,5-IP3 receptor blocker) and U73122 (a phospholipase C blocker). In conclusion, these findings demonstrate for the first time that hESC-CM exhibit functional AT-II and ET-1 signaling pathways, as well as 1,4,5-IP3-operated releasable Ca2+ stores.
Disclosure of potential conflicts of interest is found at the end of this article.
Preserving the Sacred Bond: An Audit Must Be Performed
Authors: Chabner Bruce A. 
Published: September 2008

Abstract
In light of additional questions raised in the Letters to the Editor section of this issue regarding results of the International Early Lung Cancer Action Program clinical trial on computed tomography screening for lung cancer, Editor-in-Chief of The Oncologist, Bruce A. Chabner, M.D., in this editorial calls for a thorough, complete, and impartial audit of this trial.
Surgical Implications of Coronary Arterial Anatomy in Adults with Congenital Cardiac Disease
Authors: Bogers Ad J.J.C , Eralp Ismael , Kappetein A. Pieter 
Published: September 2008

In adults with congenital heart disease coronary arterial anatomy, normal as well as anomalous, may have implications in surgical reconstruction of an underlying cardiac structure.
In addition to the diagnostic imaging, necessary in surgery for adult congenital heart disease, additional information with regard to the spatial relation between the relevant cardiac structure and the coronary arterial system may be required for planning the operation and providing a good outcome.
The congenital cardiac surgeon should have the necessary skills in coronary artery bypass techniques.
With lack of adequate data, the estimation of mortality due to complications as a result of coronary damage in surgery for adult congenital cardiac disease of below 1% seems fair.
Oxidative Stress As A Common Mediator for Apoptosis Induced-Cardiac Damage in Diabetic Rats
Authors: Dallak Mohammad M , Mikhailidis Dimitri P , Haidara Mohamed A , Bin-Jaliah Ismaeel M , Tork Olaa M , Rateb Moshira A , Yassin Hanaa Z , Al-refaie Zeinb A , Ibrahim Ibrahim M , Elawa Samy M , Rashed Laila A , Afifi Noha A 
Published: September 2008

Abstract:Aim:To investigate the possible role of oxidative stress as a common mediator of apoptosis and cardiac damage in diabetes.Materials and Methods:This experimental work was conducted on 5 groups of Wistar rats. Group I was the control group. Diabetes type 1 was induced in other groups (by streptozotocin) and animals received insulin or vitamin E (300 mg /kg body weight), both insulin and vitamin E, or no treatment for 4 weeks according to their group. At the end of the study, serum and cardiac tissues were examined for biochemical parameters of cardiac function, oxidative stress and apoptosis. Electron microscopy pictures of cardiac tissue were also evaluated for signs of cardiac damageResults:Markers of oxidative stress, apoptosis, inflammation as well as manifestations of cardiac damage as assessed by electron microscopy were significantly decreased in rats treated with both insulin and vitamin E when compared with untreated diabetic rats or rats treated with either insulin or vitamin E aloneConclusion:Administration of both vitamin E and insulin was effective in reducing markers of oxidative stress and apoptosis and improving parameters of cardiac function in experiments animals. Antioxidants might prove beneficial as an adjuvant treatment in addition to insulin in type 1 diabetes associated with manifestations of cardiac complications
Electron irradiation effects in doped high temperature superconductors YBa2Cu3−x
MxOy (M = Fe, Ni; x=0; x=0:01)
Authors: Sahakyan Aram , Nikoghosyan Sergei , Yeritsyan Hrant 
Published: September 2008

Abstract
The influence of irradiation by electrons with an energy of 8 MeV, at dose intervals between 1013 and 2×1018el/cm2, on the properties of impurity doped, high-temperature superconductor YBa2Cu3−x
MxOy (M = Fe, Ni; x=0; x=0:01) ceramics has been studied.
It has been established that, as the irradiation dose is increased, the onset temperature of the transition to the superconducting state (T
con), and the intergranular weak link coupling temperature between granules (T
mJ), exhibit an oscillation around their initial values of approximately about 1–1.5 K. This oscillation indicates that the process of radiation defect formation in HTSC occurs in multiple stages. It was also found that the critical current (J
c)decreases with an increase of the irradiation dose, and exhibits a local minimum at a dose of 8×1016el/cm2coinciding with minima for T
con and T
mJ at this dose. It was found that the introduction of Fe atoms to the ceramic decreases T
mJ, while introducing Ni atoms decreases both T
con and T
mJ; it is suggested that this is a result of Ni substitution of Cu both in Cu2 plane sites and Cu1 chain sites. The introduction of Ni causes a large change in the intergranular critical current density, J
c. A critical irradiation dose is obtained (2×1018)after which all HTSC parameters strongly decrease, i. e. the superconductivity of HTSC is destroyed.
Light polarization fingerprints on nonlinear dynamics of vertical-cavity surface-emitting lasers
Authors: Panajotov K. , Sciamanna M. , Gatare I. , Arizaleta Arteaga M. , Thienpont H. 
Published: September 2008

AbstractIn this paper we summarize the recent results on nonlinear dynamics of vertical-cavity surface-emitting lasers (VCSELs) which are bearing the fingerprints of the particular polarization properties of VCSELs. Due to the surface emission and cylindrical symmetry, VCSELs lack strong polarization anisotropy and may undergo polarization switching and polarization mode-hopping. This provides new specificities to the rich nonlinear dynamics induced in VCSELs by an external perturbation. We unveil both experimentally and theoretically these new specificities for the case of optical feedback, optical injection, and unidirectional synchronization between VCSELs.
Electron beam irradiation induced changes in liquid-crystal compound 5CB
Authors: Rath M. , Sarkar S. , Wadhawan V. , Verma R. , Das I. , Dąbrowski R. , Tykarska M. , Dhar R. 
Published: September 2008

AbstractElectron beam irradiation studies on liquid crystal material 5CB have been carried out at a temperature where the compound exists in the isotropic liquid phase. In situ time-resolved spectroscopic characterization was carried out during the irradiation. Three different transients were observed during the 2-μs electron pulse. After about 50 μs, only one transient species was found to be present, which has an absorption peak at 360 nm. Radiolysed sample exhibits a broad absorption at ∼400 nm. The dielectric measurements show that even a low level of irradiation results in a dramatic increase in the component of dielectric permittivity normal to the long axes of the molecules ε⊥′, and a corresponding decrease in the dielectric anisotropy (Δε′=ε∥′−ε⊥′ ). These studies show that 5CB is prone to substantial radiation damage on exposure to the beam of high-energy electrons.
Nanopatterning in a compact setup using table top extreme ultraviolet lasers
Authors: Wachulak P. , Capeluto M. , Menoni C. , Rocca J. , Marconi M. 
Published: September 2008

AbstractThe recent development of table top extreme ultraviolet (EUV) lasers have enabled new applications that so far were restricted to the use of large facilities. These compact sources bring now to the laboratory environment the capabilities that will allow a broader application of techniques related to nanotechnology and nanofabrication. In this paper we review the advances in the utilization of EUV lasers in nanopatterning. In particular we show results of the nanopatterning using a table-top capillary discharge laser producing 0.12-mJ laser pulses with 1.2-ns time duration at a wavelength λ = 46.9 nm. The nanopatterning was realized by interferometric lithography using a Lloyd’s mirror interferometer. Two standard photoresists were used in this work, polymethyl methacrylate (PMMA) and hydrogen silsesquioxane (HSQ). Pillars with a full width half maximum (FWHM) diameter of 60 nm and holes with FWHM diameter of 130 nm were obtained over areas in excess of 500×500 μm2.
Eagle syndrome as a cause of transient ischemic attacks
Authors: Farhat Hamad I. , Elhammady Mohamed Samy , Ziayee Habib , Aziz-Sultan Mohammad Ali , Heros Roberto C. 
Published: September 2008

Eagle syndrome is an uncommon entity but is well known in the otorhinolaryngology and oral surgery literature. This syndrome results from the compression of cranial nerves in the neck by an elongated styloid process causing unilateral cervical and facial pain. The styloid process can also cause compression of the cervical carotid arteries leading to the so-called carotid artery syndrome together with carotidynia or neurological symptoms due to flow reduction in these arteries.
The authors discuss the case of a 70-year-old man who suffered from transient ischemic attacks on turning his head to the left, with immediate remission of symptoms when his head returned to the neutral position. The patient was studied with dynamic angiography, which clearly showed focal flow restriction. Once a diagnosis was made, the styloid process was removed surgically and the patient completely recovered from his symptoms. A postoperative angiogram demonstrated complete resolution of the pathology.
Neurosurgeons might encounter patients with Eagle syndrome and should be aware of the symptoms and signs. Once the diagnosis is made, the treatment is clear and very effective.
Early brain tumor metastasis reduction following Gamma Knife surgery
Authors: Da Silva Arnaldo Neves , Nagayama Kazuki , Schlesinger David , Sheehan Jason P. 
Published: September 2008

Object
Unlike whole-brain radiation therapy, Gamma Knife surgery (GKS) is delivered in a single session for the treatment of brain metastases. The extent to which GKS can facilitate early tumor control was the focus of this study.

Methods
The authors reviewed 134 metastatic lesions in 82 patients treated with GKS at the University of Virginia who underwent follow-up MR imaging within 30 days or less of GKS. For accurate volumetry only tumors measuring 0.5 cm3 or greater in volume were included. Radiological review as well as tumor volumetry was performed to assess the tumor's response to GKS. Tumors were characterized as either enlarged (> 15% volume increase), stable (follow-up volume ± 15% of the initial volume), or decreased (> 15% volume decrease). A multivariate analysis was performed to determine factors related to each volume outcome group.

Results
Within the first month following GKS, a decrease was observed in 47.8% of the tumors. Tumor reduction varied according to carcinoma histopathological subtype, with 46.4% of non–small cell lung carcinomas, 70% of breast carcinomas, and 22.6% of melanomas showing volume reduction within 30 days after GKS. The mean volume decrease was 41.7%. For the remaining tumors, 41% were stable and 11.2% increased in volume. The overall analysis showed that there was a significant difference in percentage tumor change according to histopathological type (p < 0.001). There was a trend toward increased tumor reduction in those carcinoma types that are traditionally viewed as radiation sensitive (breast and non–small cell lung carcinomas).

Conclusions
Gamma Knife surgery can offer patients early substantial volume reduction in many brain metastases. In instances in which early volume reduction of limited intracranial disease is desired, GKS may be used alone or before whole brain radiation therapy.
Sulcal and ventricular trajectories in stereotactic surgery
Authors: Elias W. Jeff , Sansur Charles A. , Frysinger Robert C. 
Published: September 2008

Object
The authors analyzed deep brain stimulation electrode trajectories on MR images to identify risks of cerebrovascular complications associated with the number of electrode insertions, traversal of a sulcus, and penetration of the ventricle.

Methods
Pre- and postoperative MR volumes were fused to determine the proximity of electrodes to a sulcus or ventricle and whether there were cortical, subcortical, or intraventricular complications. Complications were further classified as hemorrhagic or nonhemorrhagic and symptomatic or asymptomatic. The authors examined 258 electrode implantation for deep brain stimulation. There were 4 symptomatic events (1.6% incidence): 3 hemorrhagic and 1 nonhemorrhagic, all within the cortex. Asymptomatic events included cortical hemorrhage in 1 patient, nonhemorrhagic cortical changes in 6, pallidal hemorrhage in 1, thalamic infarction in 1, and intraventricular hemorrhage (IVH) in 5 patients.

Results
Proximity to a sulcus was a significant risk factor for hemorrhagic and nonhemorrhagic cortical complications (p = 0.001). There was a complication rate of 10.1% within the trajectories penetrating or adjacent to a sulcus, and a 0.7% rate with trajectories clearly positioned within the gyrus. Asymptomatic IVH was observed in 5% of ventricular penetrations. A history of hypertension was a risk factor for cortical hemorrhage (p = 0.019), but not for cortical ischemic/edematous events (p = 0.605). The number of electrode penetrations did not differ between patients with and without complications (p = 0.868), and the sequence of electrode insertions was not a risk factor in bilateral surgeries.

Conclusions
Symptomatic cortical complications occur when electrodes traverse close to a sulcus. Asymptomatic IVH occurs infrequently with ventricular penetration. Despite intraoperative efforts to avoid cortical sulci, a higher than expected incidence of electrode proximity to the sulci was identified on careful postoperative trajectory analysis. This finding emphasizes the importance of assiduously planning trajectories and reviewing cases with thorough MR analysis.
A Convenient and Effective Method for the Regioselective Deuteration of Alcohols
Authors: Maegawa Tomohiro , Fujiwara Yuta , Inagaki Yuya , Monguchi Yasunari , Sajiki Hironao 
Published: September 2008

AbstractThe convenient and regioselective deuteration of hydroxy groups on vicinal carbons was achieved by the combination of 5% ruthenium on carbon (Ru/C), hydrogen gas and deuterium oxide (D2O).
Polylactide‐recycled wood fiber composites
Authors: Pilla Srikanth , Gong Shaoqin , O'Neill Eric , Yang Liqiang , Rowell Roger M. 
Published: September 2008

AbstractPolylactide (PLA)‐recycled wood fiber (RWF) composites with a small amount of silane were compounded using a kinetic‐mixer and molded using an injection molding machine. The molded PLA‐RWF composites were characterized using gel permeation chromatography, scanning electron microscope, X‐ray diffraction, differential scanning calorimeter, tensile testing machine, and a dynamic mechanical analyzer. As observed in the stress–strain plots, the amount of necking before fracture decreased with an increasing RWF content. Similarly, the strain‐at‐break also decreased with the RWF content. The tensile strength remained the same irrespective of the RWF content. Both the tensile modulus and the storage modulus of the PLA‐RWF composites increased with the RWF content. The degree of crystallinity of the PLA increased with the addition of RWF. No reduction in the number–average molecular weight (Mn) was observed for pure PLA and PLA‐10%RWF‐0.5%Silane composites after injection molding; however, substantial reduction in Mn was found in PLA‐20%RWF‐0.5%Silane composites. Finally, a theoretical model based on Halpin–Tsai empirical relations is presented to compare the theoretical results with that of the experimental results. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009