bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resident duty hour regulation and patient safety: establishing a balance between concerns about resident fatigue and adequate training in neurosurgery
Authors: Grady M. Sean , Batjer H. Hunt , Dacey Ralph G. 
Published: May 2009

Postgraduate training in medicine has been under scrutiny over the past 10 years with a major focus on physician personal health and patient safety. The culmination of a series of events led to the 80-hour work week instituted by the Accreditation Council on Graduate Medical Education in 2003. The effect this mandate has had on surgical education, and specifically training in neurological surgery, has been incompletely evaluated. Nevertheless, external pressure has prompted the Institute of Medicine to issue a new report on resident work hours and patient safety.
In this report, the authors focus on the unique aspects of neurosurgical training in which physicians are trained to safely and effectively carry out complex high-risk tasks, the experience from abroad where work hours are reduced to well below 80 hours/week, and the risk that further reduction in work hours poses to the public. The authors conclude that there must be an adequate balance between the risks associated with resident fatigue and those associated with an inexperienced neurosurgical work force for public health.
Edema formation in the hyperacute phase of ischemic stroke
Authors: Gerriets Tibo , Walberer Maureen , Ritschel Nouha , Tschernatsch Marlene , Mueller Clemens , Bachmann Georg , Schoenburg Markus , Kaps Manfred , Nedelmann Max 
Published: May 2009

Object
Brain edema formation is a serious complication of ischemic stroke and can lead to mechanical compression of adjacent brain structures, cerebral herniation, and death. Furthermore, the space-occupying effect of edema impairs regional cerebral blood flow (rCBF), which is particularly important in the penumbra phase of stroke. In the present study, the authors evaluated the natural course of edema formation in the hyperacute phase of focal cerebral ischemia.

Methods
Middle cerebral artery occlusion (MCAO) or a sham procedure was performed in rats within an MR imaging unit (in-bore occlusion). Both pre- and postischemic images could be compared on a pixel-by-pixel basis. The T2 relaxation time (T2RT), a marker for brain water content, was measured in regions of interest.

Results
A significant increase in the T2RT was detectable as early as 20–45 minutes after MCAO. At this early time point the midline shift (MLS) amounted to 0.214 ± 0.092 cm in the MCAO group and 0.061 ± 0.063 cm in the sham group (p < 0.007). The T2RT and MLS increased linearly thereafter. Evans blue dye was intravenously injected in additional animals 20 and 155 minutes after MCAO. Extravasation of the dye was visible in all animals, indicating increased permeability of the blood-brain barrier.

Conclusions
Vasogenic brain edema occurs much earlier than expected following permanent MCAO and leads to MLS and mechanical compression of adjacent brain structures. Since compression effects can impair rCBF, early edema formation can significantly contribute to infarct formation and thus represents a promising target for neuroprotection.
Secondary gliosarcoma: a review of clinical features and pathological diagnosis
Authors: Han Seunggu J. , Yang Isaac , Tihan Tarik , Chang Susan M. , Parsa Andrew T. 
Published: May 2009

Object
Although secondary gliosarcoma after treatment of primary glioblastoma multiforme has been described, little is known of these rare tumors. In this article the authors review the literature on secondary gliosarcoma, with attention to clinical course and pathological features.

Methods
A PubMed search of the key word intracranial “gliosarcoma” with and without “radiation” or “radiotherapy” in humans was performed. The 204 citations yielded were screened for relevancy to gliosarcomas that occur after treatment of previous intracranial neoplasms.

Results
A search of the literature yielded 24 relevant articles, combined for a total of only 12 cases of secondary gliosarcoma and 12 cases of radiation-induced gliosarcoma. Of the 12 cases of secondary gliosarcoma, all were previously treated with surgery and radiotherapy (mean dose 50.7 Gy), with a mean survival of 13 months since time of gliosarcoma diagnosis (range 6.9–19.4 months). In the cases of radiation-induced gliosarcoma, the mean dose of previous radiotherapy was 51.3 Gy (median 54 Gy, range 24–60 Gy), and the mean survival since gliosarcoma diagnosis was 6.7 months (median 6 months, range 2–10 months).

Conclusions
Secondary gliosarcoma and radiation-induced gliosarcoma are exceedingly rare. The literature on secondary gliosarcoma illustrates a more favorable survival than for primary gliosarcoma but remains limited regarding clinical and radiographic presentation, response to treatment, and pathogenesis. The results of the present review also support the notion that secondary gliosarcomas and radiation-induced gliosarcomas are distinct entities, with longer survival and shorter latency of gliosarcoma induction seen in the former. Efforts to elucidate the role of radiotherapy in the induction of gliosarcomas may yield new insights into therapeutic risks of cranial radiation and CNS tumor pathogenesis.
Neurosurgical management of intracranial lesions in the pregnant patient: a 36-year institutional experience and review of the literature
Authors: Cohen-Gadol Aaron A. , Friedman Jonathan A. , Friedman Jennifer D. , Tubbs R. Shane , Munis James R. , Meyer Fredric B. 
Published: May 2009

Object
A review of the literature has revealed scant data related to neurosurgical treatment of gravid patients. The authors reviewed their experience with the neurosurgical treatment of pregnant women to better characterize the optimal management strategies for intracranial pathological entities in this population.

Methods
Between July 1969 and July 2005, 34 patients with documented pregnancy and concomitant intracranial pathological entities were treated at the authors' institution. The average age of the gravid patients at presentation was 27 ± 6 years. Twelve patients harbored vascular and 14 patients harbored neoplastic lesions. Four gravid patients suffered from traumatic intracranial hemorrhage, 2 had primary intracerebral hemorrhage, and 2 had hydrocephalus. The medical records of these patients were reviewed to assess the outcome for the mothers and fetuses.

Results
Nineteen pregnant patients (56%) underwent a neurosurgical procedure after induction of general anesthesia. Of these, 14 (74%) underwent craniotomies for clipping/resection of their lesion, 2 (10%) underwent stereotactic biopsies, and 3 (16%) underwent CSF shunting procedures. Three patients (9%) delivered by cesarean section followed by their neurosurgical procedure, and 5 (15%) underwent therapeutic abortion preoperatively to allow for radiation therapy early in their pregnancy (4 of these patients underwent surgery prior to their therapeutic abortion). Eleven patients (32%) were treated nonoperatively while pregnant, and 3 of these received their treatment after delivery. There was no operative maternal mortality or permanent morbidity. The fetuses did not suffer from any complications related to the mother's neurosurgical procedure.

Conclusions
Based on the authors' experience and a review of the literature, surgery for intracranial lesions in pregnant patients is generally well tolerated by both mother and fetus. Preoperative delivery by cesarean section of term or near-term babies is reasonable. Some patients treated conservatively may deteriorate and require an operation.
Microstimulation-induced inhibition as a tool to aid targeting the ventral border of the subthalamic nucleus
Authors: Lafreniere-Roula Myriam , Hutchison William D. , Lozano Andres M. , Hodaie Mojgan , Dostrovsky Jonathan O. 
Published: May 2009

Object
The aim of the current study was to examine and compare the aftereffects of local high-frequency microstimulation through the recording electrode on the firing of neurons in the subthalamic nucleus (STN) and the substantia nigra pars reticulata (SNr) in patients undergoing surgery for deep brain stimulation. Deep brain stimulation has been playing an increasing role in the treatment of Parkinson disease, with the subthalamic nucleus (STN) being the preferred implantation target. Changes in cellular activity indicative of the borders of the STN are typically used during surgery to determine the extent of the STN and locate the optimal target, but in some cases borders may be difficult to identify. In this study the authors compared the effects of microstimulation in the SNr and STN. In previous studies they have shown that microstimulation in the internal globus pallidus, which is functionally similar to the SNr, inhibits firing, whereas similar microstimulation in the STN has minimal effect. The presence of inhibition in the SNr but not in the STN could be used as an additional criterion to help identify the location of the border between the STN and SNr.

Methods
Dual microelectrode recordings were performed during stereotactic surgery in 4 patients. Well-isolated high-amplitude units were stimulated extracellularly through the recording microelectrode with 0.5-second trains of high frequency (200 Hz) and low current (≤ 5 μA).

Results
In the majority (92%) of SNr neurons, this type of stimulation led to a period of inhibition lasting several hundreds of milliseconds following the end of the train. In contrast, only 1 neuron of 70 judged to be in the STN by other criteria was inhibited by this type of microstimulation, and this neuron was located at the ventral border of the STN.

Conclusions
These findings indicate that prolonged inhibition of firing following low-amplitude high-frequency microstimulation via the recording electrode is a consistent feature of almost all SNr neurons and rarely if ever occurs in STN neurons. This feature therefore provides a useful additional finding that can be used to help identify the border between the STN and SNr.
Fluorescent pH and Oxygen Probes of the Assessment of Mitochondrial Toxicity in Isolated Mitochondria and Whole Cells
Authors: Hynes James , Natoli Edward , Will Yvonne 
Published: May 2009

AbstractOxygen consumption measurements provide information on the activity of the mitochondrial electron transport chain and such measurements can be carried out on both isolated mitochondria and whole cells. Additional information is available on glycolytic metabolism by assessing extracellular acidification. The protocols in this unit describe how recently developed fluorescent pH‐ and O2‐sensitive probes can be used as tools for the assessment of mitochondrial toxicity and metabolic function in standard microtiter plates. In addition, protocols for the isolation of mitochondria from different tissue sources are provided. Curr. Protoc. Toxicol. 40:2.16.1‐2.16.22. © 2009 by John Wiley & Sons, Inc.
Non‐Hydrolyzable RNA–Peptide Conjugates: A Powerful Advance in the Synthesis of Mimics for 3′‐Peptidyl tRNA Termini
Authors: Moroder Holger , Steger Jessica , Graber Dagmar , Fauster Katja , Trappl Krista , Marquez Viter , Polacek Norbert , Wilson Daniel N. , Micura Ronald 
Published: April 2009

AbstractTranslation of specific small peptideson the ribosome can confer resistance to macrolide antibiotics. To reveal the molecular details of this and related phenomena, stable RNA–peptide conjugates that mimic peptidyl‐tRNA would be desirable, especially for ribosome structural biology. A flexible solid‐phase synthesis strategy now allows efficient access to these highly requested derivatives without restriction on the RNA and peptide sequences.magnified image
Application of Taguchi method to investigate the effects of process factors on the performance of batch emulsion polymerization of vinyl chloride
Authors: Shahbazian Alen , Navarchian Amir H. , Pourmehr Mahdi 
Published: May 2009

AbstractIn this article, the influences of five operating variables on the molecular weight (or K‐value), polydispersity index (PDI), as well as polymerization yield of emulsion poly (vinyl chloride) in batch reactor were investigated simultaneously using Taguchi experimental design approach. The variables were temperature (T), water to monomer weight ratio (r), concentrations of initiator ([I]) and emulsifier ([E]), and agitation speed (S). Statistical analysis of results revealed the significance order of factors affecting the product qualities and quantity. It was found that the reaction temperature is the principal operating factor to control the molecular weight, and this is attributed to promotion of chain transfer reactions to monomer in this system. The effect of this factor on PDI is also comprehensively discussed. The significance sequences of important factors on yield are: S > [E] > r. The polymerization yield increases with S and [E] but decreases as r is increased. The relative optimum condition for a typical paste application was also determined using overall evaluation criteria. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Microstructure of carbon nanofiber/thermotropic liquid crystalline polymer composites
Authors: Lee Sungho , Ogale Amod A. 
Published: May 2009

AbstractThe properties and microstructure of a thermotropic liquid crystalline polymer (TLCP, Vectran V400P) were investigated in the presence of carbon nanofibers (CNF). The electrical conductivity of TLCP increased with an addition of CNFs. The thermal analysis of pure TLCP and its composites revealed that a glass transition at ∼ 110°C did not change significantly. However, a decrease of tensile modulus and strength was observed with the addition of CNFs. WAXD studies showed a decrease of Herman's orientation parameter, indicating reduction of anisotropy of TLCP. Further, the disruption of molecular orientation of TLCPs was inferred by SEM and TEM analysis. SEM micrographs revealed a fibrillar structure for pure TLCPs at a macro‐scale (2–5 μm). However, this structure was not observed in composites at the same scale even though micro‐size fibrils (0.05 μm) were found with the addition of CNFs. TEM micrographs displayed banded structures of pure TLCPs, but these structures were not significant in the vicinity of CNFs. These observations confirmed that a decrease of molecular alignment and disruption of fibrillar structure of TLCP, in the presence of nanofibers, are attributed to a significant decrease in tensile modulus and strength. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Statistical evaluation of laser energy density effect on mechanical properties of polyamide parts manufactured by selective laser sintering
Authors: Beal V. E. , Paggi R. A. , Salmoria G. V. , Lago A. 
Published: May 2009

AbstractSelective laser sintering (SLS) is a rapid manufacturing technology that builds layer‐by‐layer solid object from particulate materials. Nowadays there are materials that are used to produce prototypes and end‐user parts. Powders might be made from metals, ceramics, polymers, and composites. The union or fusion of the particles is made by the energy provided by a heated environment and a laser beam. Parts are built based on data extracted from its CAD design. The process has many variables that directly affect the mechanical properties of the parts. One important and direct processing parameter is laser energy density. This work evaluated the effect of the variation of the energy density in the mechanical properties of a polymeric material by changing laser beam speed and average power. The analyzed variables were stress at 10% of elongation, flexural modulus, and density of the samples built with polyamide 2200 (PA2200‐EOSINT) using a CO2 laser (10 W). Specimens obtained by combination of different laser powers (2.7, 3.4, and 4.1 W) and laser scan speeds (39.0, 44.5, and 50.0 mm/s) were submitted to flexural tests. Additionally, volumetric density was calculated with mass and physical dimensions of specimens, and micrograph were taken using scanning electron microscope to analyze the changes of the sintering degree. The results indicated that laser power had more influence over density and mechanical properties than scan speed. The microstructures presented good correlation with the statistical results. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
5‐in‐1 biodiesel: an approach to combining five biodiesel gas chromatographic methods on a single instrument
Authors: McCurry James D. , Norman Wesley 
Published: May 2009

AbstractJames D. McCurry and Wesley Norman report on a new technology developed at Agilent Technologies. A small external, isothermal, capillary‐column oven is used to isolate a polar wax column from a high‐temperature column on a single gas chromatograph (GC). This allows five different biodiesel methods to reside on the same GC which would otherwise require two separate instruments. The isothermal biodiesel methods are used to test the external column oven performance and demonstrate the ability to combine these methods on a single GC. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd
Non‐Linear Model Predictive Control: A Personal Retrospective
Authors: Bequette B. Wayne 
Published: April 2009

AbstractAn overview of non‐linear model predictive control (NMPC) is presented, with an extreme bias towards the author's experiences and published results. Challenges include multiple solutions (from non‐convex optimization problems), and divergence of the model and plant outputs when the constant additive output disturbance (the approach of dynamic matrix control, DMC) is used. Experiences with the use of fundamental models, multiple linear models (MMPC), and neural networks are reviewed. Ongoing work in unmeasured disturbance estimation, prediction and rejection is also discussed.
The heterogeneous distribution of functional synaptic connections in rat hippocampal dissociated neuron cultures
Authors: Kudoh Suguru N. , Kiyohara Ai , Taguchi Takahisa 
Published: May 2009

AbstractThe dynamics of functional synaptic connections are critical for information processing systems in the brain, such as perception and learning. Using rat hippocampal cells cultured on multielectrode arrays, we investigated the spatiotemporal pattern of spontaneous action potentials. The neurons developed connections and a characteristic high‐frequency bursting (HFB) activity was observed transiently. After the period of HFB activity, the distribution of spontaneous activity changed drastically with the appearance of neurons with frequent electrical activity and neurons with little activity in the network. The functional connections of all the combinations of recorded spike trains were estimated and depicted simultaneously in a Connection Map. This map revealed that each culture contained hublike neurons with many functional connections, suggesting that the cultures of dissociated rat hippocampal neurons on multielectrode arrays formed heterogeneous networks of functional connections. In addition, the functional connections were drastically reorganized after the induction of synaptic potentiation, and novel hub neurons emerged. These results indicate that spontaneous activity is enough to construct dynamic assemblies of neurons connected to each other by functional synaptic connections, and that synaptic potentiation can induce reorganization of such assemblies of neurons. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(6): 41–49, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10063
Position command shaping for vibration suppression considering target position correction
Authors: Yamamoto Masafumi , Ito Kazuaki , Iwasaki Makoto , Matsui Nobuyuki 
Published: May 2009

AbstractThis paper presents a command shaping technique based on a minimum jerk control approach that takes into consideration target position correction during motion, for the fast and precise positioning in vibratory mechatronic systems. The positioning controller is designed using a two‐degree‐of‐freedom control: a feedback compensator is synthesized by H∞ control design to ensure the robust stability, while a feedforward compensator suppresses the vibration in response based on a coprime factorization expression of the plant mechanism. The command shaping, on the other hand, eliminates the corresponding vibration components of the primary and secondary models in the position command, where the continuity of jerk component in the command can be ensured against the target position correction. The effectiveness of the proposed shaping technique has been verified by experiments using a table drive system on a machine stand. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(3): 38–47, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20838
Post‐treatment of anaerobically treated medium‐age landfill leachate
Authors: Akkaya Ebru , Demir Ahmet , Karadag Dogan , Varank Gamze , Bilgili M. Sinan , Ozkaya Bestamin 
Published: May 2009

AbstractThis study focused on the removal of COD and NH4+ from medium‐age leachate. Experiments were performed in a laboratory‐scale upflow anaerobic sludge blanket (UASB), a membrane bioreactor (MBR), and using magnesium ammonium phosphate (MAP) precipitation. MBR and MAP were used for the post‐treatment steps for anaerobically treated leachate to increase the removal of organics and ammonium. The UASB reactor removed nearly all biodegradable organics and supplied constant effluent COD for all concentration ranges of influent leachate. Ammonium removal efficiency in the UASB reactor was relatively low and the average value was ∼7.9%. Integration of MBR to the effluent of UASB reactor increased the average COD removal efficiency from 51.8 to 65.6% and maximum removal efficiency increased to 74.3%. MAP precipitation was applied as a final step to decrease the ammonium concentration in the effluent of UASB+MBR reactors. The effect of pH and the molar ratio of MAP constituents on the removal of ammonium were evaluated. At optimal conditions (pH: 9.0 and Mg/NH4/PO4: 1/1.2/1.2), 96.6% of ammonium was removed and MAP provided additional COD and turbidity treatment. Consequently, the combined system of MBR and MAP precipitation could be used as an appropriate post treatment option for the anaerobically treated medium‐age landfill leachate. © 2009 American Institute of Chemical Engineers Environ Prog, 2010