bluuebunny/crossref_metadata_2025_split huggingface dataset:
Universal Scaled Strength Behaviour for Micropillars and Nanoporous Materials
Authors: Derby Brian , Dou Rui 
Published: September 2009

AbstractThe strength of submicron FCC structure metal columns, σ, fabricated by FIB machining or electrodeposition, shows a strong correlation with specimen diameter, d, with σ/μ = A(d/b)−0.63, where A is a constant, μ is the single crystal shear modulus resolved onto the slip system and b is the Burgers' vector. The strength of BCC structure metals does not show such a well defined correlation with size across different metals but the data occupies the same region of parameter space as with the FCC metals. Nanoporous gold specimens show a similar size-correlated behaviour but with an exponent of −0.5. This may indicate different mechanisms operating in each case.
Piezoresponse Force Microscopy Characterization of PTO Thin Films
Authors: Morelli Alessio , Venkatesan Sriram , Palasantzas George , Kooi Bart J. , De Hosson Jeff 
Published: September 2009

AbstractThe piezoelectric properties of PTO thin films grown by pulsed laser deposition are investigated with piezoresponse force microscopy and transmission electron microscopy. The as-grown films exhibit upward polarization, and inhomogeneous distribution of piezoelectric characteristics. The data obtained reveal imprint during piezoresponse force microscopy measurements, nonlinearity in the piezoelectric deformation, and limited retention loss. Moreover, transmission electron microscopy shows the presence of defects near the film/substrate interface, which can be associated with the variations of piezoelectric properties.
Vertex scalp mass as presenting sign of a complex intracranial vascular malformation
Authors: Massimi Luca , De Bonis Pasquale , Esposito Giuseppe , Novegno Federica , Pettorini Benedetta , Tamburrini Gianpiero , Caldarelli Massimo , Di Rocco Concezio 
Published: September 2009

Scalp masses are not infrequently encountered in daily clinical practice. They are represented by a wide spectrum of different clinical entities and are usually managed by an excision or by simple observation. Although it happens rarely, head lumps may hide an underlying cranioencephalic malformation that has to be preoperatively diagnosed to perform an appropriate treatment.
Cerebral arteriovenous malformations (AVMs) are not included among the intracranial malformations connected with a scalp mass. The authors report on the unusual case of a child harboring a complex intracranial AVM that initially presented as a small scalp mass. Actually, this young boy came to the authors' attention just for a small, soft, pulsatile, and reducible mass of the vertex that produced a circumscribed bone erosion. The presence of macrocranium and venous engorgement of the face, however, suggested the presence of an intracranial “mass.” The neuroimaging investigations pointed out a temporal AVM causing dilation of the intracranial sinuses and ectasia of the vein of the scalp; one of the veins was appreciable as a lump on the vertex.
Navigating the gray zone: a guideline for surgical decision making in obstetrical brachial plexus injuries
Authors: Bain James R. , DeMatteo Carol , Gjertsen Deborah , Hollenberg Robert D. 
Published: September 2009

Object
In the literature, the best recommendations are imprecise as to the timing and selection of infants with obstetrical brachial plexus injury (OBPI) for surgical intervention. There is a gray zone (GZ) in which the decision as to the benefits and risks of surgery versus no surgery is not clear. The authors propose to describe this category, and they have developed a guideline to assist surgical decision-making within this GZ.

Methods
The authors first performed a critical review of the medical literature to determine the existence of a GZ in other clinical publications. In those reports, 47–89% of infants with OBPI fell within such a GZ. Complete recovery in those reported patients ranged from 9 to 59%. Using a prospective inception cohort design, all infants referred to the OBPI Clinic at McMaster Children's Hospital were systematically evaluated up to 3 years of age. The Active Movement Scale scores were compared for surgical and nonsurgical groups of infants in the GZ to identify any important trends that would guide surgical decision-making.

Results
In the authors' population of infants with OBPI, 81% fell within the GZ, of whom 44% achieved complete recovery. Mean scores differed significantly between surgery and no surgery groups in terms of total Active Movement Scale score and shoulder abduction and flexion at 6 months. Elbow flexion and external rotation differed at 3 months.

Conclusions
There is compelling evidence that there is a group of infants with OBPI in whom the assessment of the risk/benefit ratio for surgical versus nonsurgical treatment is not evident. These infants reside within what the authors have called the GZ. Based on their results, a guideline was derived to assist clinicians working with infants with OBPI to navigate the GZ.
Internal structure in pineal cysts on high-resolution magnetic resonance imaging: not a sign of malignancy
Authors: Pastel David A. , Mamourian Alexander C. , Duhaime Ann-Christine 
Published: September 2009

Object
In this paper, the authors' goal was to determine whether benign pineal cysts have smooth walls or internal structure on high-resolution MR imaging and to evaluate their imaging characteristics on FLAIR images.

Methods
The authors retrospectively reviewed the MR imaging findings in 60 consecutive patients who were reported to have pineal cysts over a 19-month period. Patients were identified retrospectively using a word search of radiology reports. Of these 60 patients, 24 with stable follow-up imaging or pathological proof of a pineal cyst were included in this study. In all cases, axial or sagittal FLAIR images were available, and in 10 of 24 patients the authors obtained sagittal images using fast imaging employing steady-state acquisition (FIESTA). For those cases in which FIESTA studies were obtained, the authors classified the cysts into 1 of 4 categories based on their appearance. Eighteen of 24 cases were performed with intravenous contrast.

Results
Of the 24 cases, 21 had signal intensity on FLAIR images that differed from that of CSF. Of the 10 cases with FIESTA, 6 had evidence of internal structure within the pineal cyst. The authors found it of interest that 20 of the 24 patients were female.

Conclusions
Although the presence of a thin wall supports the diagnosis of a benign pineal cyst, fine internal septations or small internal cysts are common on high-resolution MR imaging and this finding should not be considered evidence of an underlying tumor. It is typical for pineal cysts to have relaxation times that differ from CSF as determined by FLAIR imaging.
Experimental investigation of encephalomyosynangiosis using gyrencephalic brain of the miniature pig: histopathological evaluation of dynamic reconstruction of vessels for functional anastomosis
Authors: Nakamura Mitsunobu , Imai Hideaki , Konno Kenjiro , Kubota Chisato , Seki Koji , Puentes Sandra , Faried Ahmad , Yokoo Hideaki , Hata Hidekazu , Yoshimoto Yuhei , Saito Nobuhito 
Published: September 2009

Object
Encephalomyosynangiosis (EMS) is a surgical treatment for moyamoya disease that is widely used to provide increased intracranial blood flow via revascularization by arterial anastomosis from the external carotid artery. However, the angiogenic mechanism responsible for the revascularization induced by EMS has not been systematically evaluated. In this study the authors investigated the chronological angiogenic changes associated with EMS to clarify the favorable factors and identify revascularization mechanisms by using an experimental internal carotid artery occlusion (ICAO) model in the miniature pig.

Methods
Fourteen miniature pigs were used, 11 of which underwent ICAO before transcranial surgery for EMS was performed. Animals were allowed to recover for 1 week (4 pigs) or 4 weeks (7 pigs) after EMS. Control group animals were treated in the same way, but without occlusion (3 pigs). Magnetic resonance imaging, angiography, and histological investigation were performed.

Results
One week after EMS, on histological examination of both the ICAO and control groups it was found that the transplanted temporal muscle had adhered to the arachnoid via a granulation zone, which was enriched with immune cells such as macrophages associated with the angiogenic process. Four weeks after EMS, angiography and histological examination of the ICAO group showed patent anastomoses between the external carotid artery and the cortical arteries without any detectable boundary between the temporal muscle and the cerebral cortex. In contrast, histological examination of the control group found scar tissue between the cerebral cortex and temporal muscle.

Conclusions
The initial step for formation of anastomoses resembles the process of wound healing associated with repair processes such as active proliferation of macrophages and angiogenesis within the new connective tissue. Functional revascularization requires a suitable environment (such as tissue containing vascular beds) and stimulus (such as ischemia) to induce vascular expansion.
Resonant and notch behavior in intracranial pressure dynamics
Authors: Wagshul Mark E. , Kelly Erin J. , Yu Hui Jing , Garlick Barbara , Zimmerman Tom , Egnor Michael R. 
Published: September 2009

Object
The intracranial pulse pressure is often increased when neuropathology is present, particularly in cases of increased intracranial pressure (ICP) such as occurs in hydrocephalus. This pulse pressure is assumed to originate from arterial blood pressure oscillations entering the cranium; the fact that there is a coupling between the arterial blood pressure and the ICP is undisputed. In this study, the nature of this coupling and how it changes under conditions of increased ICP are investigated.

Methods
In 12 normal dogs, intracarotid and parenchymal pulse pressure were measured and their coupling was characterized using amplitude and phase transfer function analysis. Mean intracranial ICP was manipulated via infusions of isotonic saline into the spinal subarachnoid space, and changes in transfer function were monitored.

Results
Under normal conditions, the ICP wave led the arterial wave, and there was a minimum in the pulse pressure amplitude near the frequency of the heart rate. Under conditions of decreased intracranial compliance, the ICP wave began to lag behind the arterial wave and increased significantly in amplitude. Most interestingly, in many animals the pulse pressure exhibited a minimum in amplitude at a mean pressure that coincided with the transition from a leading to lagging ICP wave.

Conclusions
This transfer function behavior is characteristic of a resonant notch system. This may represent a component of the intracranial Windkessel mechanism, which protects the microvasculature from arterial pulsatility. The impairment of this resonant notch system may play a role in the altered pulse pressure in conditions such as hydrocephalus and traumatic brain swelling. New models of intracranial dynamics are needed for understanding the frequency-sensitive behavior elucidated in these studies and could open a path for development of new therapies that are geared toward addressing the pulsation dysfunction in pathological conditions, such as hydrocephalus and traumatic brain injury, affecting ICP and flow dynamics.
Intracranial growing teratoma syndrome mimicking tumor relapse: a diagnostic dilemma
Authors: Kong Doo-Sik , Nam Do-Hyun , Lee Jung-Il , Park Kwan , Kim Jong Hyun , Shin Hyung Jin 
Published: September 2009

Object
It is important to differentiate growing teratoma syndrome (GTS) from tumor recurrence in the setting of an enlarging residual mass present after treatment of intracranial germ cell tumors (GCTs). The aim of this study was to determine the incidence of intracranial GTS and present its clinical manifestations in detail.

Methods
The authors performed a retrospective cohort study of 52 consecutive patients with newly diagnosed intracranial GCTs who presented between January 2000 and December 2006. The records were screened to identify a study cohort in which all patients had regrowing tumor mass despite normalization of tumor markers during or after treatment of GCTs.

Results
In 6 (11.5%) of 52 patients the pathological diagnosis was GTS. The median patient age at diagnosis was 14.5 years (range 2 months–17 years), and the primary tumors included 4 mixed GCTs and 2 immature teratomas. After second-look surgery, histological testing revealed the lesions to be mature teratoma in all patients. Three of 6 patients subsequently underwent radiation therapy and 1 patient received additional chemotherapy for spinal seeding.

Conclusions
In enlarging residual masses after treatment of intracranial GCTs, GTS should be kept in mind in the differential diagnosis of tumor recurrence especially if there is a radiographic mismatch with serum marker test results. If technically feasible, second-look surgery may be necessary for an accurate diagnosis.
The outcome of tethered cord release in secondary and multiple repeat tethered cord syndrome
Authors: Al-Holou Wajd N. , Muraszko Karin M. , Garton Hugh J. , Buchman Steven R. , Maher Cormac O. 
Published: September 2009

Object
After primary repair of a myelomeningocele or a lipomyelomeningocele, patients can present with symptoms of secondary tethered cord syndrome (TCS). After surgical untethering, a small percentage of these patients can present with multiple repeat TCS. In patients presenting with secondary or multiple repeat TCS, the role as well the expected outcomes of surgical untethering are not well defined.

Methods
Eighty-four patients who underwent spinal cord untethering after at least 1 primary repair were retrospectively evaluated using scaled and subjective outcome measures at short-term and long-term follow-up visits. Outcomes were analyzed for predictive measures using multivariate logistic regression.

Results
Surgical untethering was performed in 66 patients with myelomeningoceles and 18 patients with lipomyelomeningoceles. Fourteen patients underwent multiple repeat spinal cord untethering. Patients were followed up for an average of 6.2 years. Most patients had stability of function postoperatively. Motor function and weakness improved in 7 and 16% of patients at 6 months, respectively, and 6 and 19% of patients at long-term follow-up evaluation, respectively. Of the patients who presented with back pain, 75% had improvement in symptoms at 6 months postoperatively. Younger age at untethering was significantly associated with worse long-term neurological outcomes. The number of previous untethering procedures, original diagnosis, sex, anatomical level, and degree of untethering had no effect on surgical outcomes.

Conclusions
Patients presenting with secondary or multiple repeat TCS may benefit from surgical untethering.
Postoperative cerebrospinal fluid wound leakage as a predictor of shunt infection: a prospective analysis of 205 cases
Authors: Jeelani N. u. Owase , Kulkarni Abhaya V. , DeSilva Pani , Thompson Dominic N. P. , Hayward Richard D. 
Published: September 2009

Object
The purpose of this study was to audit some of the risk factors for CSF shunt infections within the authors' practice and analyze the statistical significance of these factors.

Methods
The authors used their own contemporaneously collected shunt database in this study. All shunt procedures performed over a 2-year period between March 2000 and February 2002 at Great Ormond Street Hospital, London, were analyzed. For the purposes of this study, positive CSF cultures were a prerequisite for a data set to qualify as a shunt infection. The authors studied the effects of patient age, the etiology of hydrocephalus, whether the surgery was primary shunt placement versus a revision, the surgeon's level of experience, whether the surgery was performed on an elective or emergency basis, and the presence or absence of a perioperative CSF leak. Statistical analyses were performed.

Results
Two hundred and five patients with a mean (± SD) age at surgery of 27.9 ± 43.0 months were included in this study. Shunt infections developed in 17 patients (8.3%) at a median of 42 days postoperatively (range 14–224 days). The presence of a perioperative CSF leak was the only variable that showed a statistically significant association with the occurrence of a shunt infection, with an infection rate of 57.1% compared to 4.7% in cases with no leak (OR 27.0 [95% CI 7.7–94.3]). The cause of hydrocephalus, elective versus emergency surgery, level of surgeon experience, a primary versus a revision procedure, and patient age did not have a bearing on the infection risk.

Conclusions
The presence of a perioperative CSF leak puts pediatric patients at a very high risk of shunt infection. Aside from prevention, the optimal management of such CSF leaks require further investigation.
Experiences with a gravity-assisted valve in hydrocephalic children
Authors: Haberl Ernst Johannes , Messing-Juenger Martina , Schuhmann Martin , Eymann Regina , Cedzich Cornelia , Fritsch Michael J. , Kiefer Michael , Van Lindert Eric Johannes , Geyer Christian , Lehner Markus , Rohde Veit , Stroux Andrea , von Berenberg Petra 
Published: September 2009

Object
Over the past decade, a gravity-assisted valve (GAV) has become a standard device in many European pediatric hydrocephalus centers. Because past comparative clinical outcome studies on valve design have not included any GAV, the authors in this trial evaluated the early results of GAV applications in a pediatric population.

Methods
For a minimum of 2 years the authors monitored 169 of 182 hydrocephalic children who received a pediatric GAV at their first CSF shunt insertion (61.5%) or as a substitute for any differential pressure valve (38.5%) at 1 of 7 European pediatric hydrocephalus centers. Outcomes were categorized as valve survival (primary outcome) or shunt survival (secondary outcome). The end point was defined as valve explantation.

Results
Within a follow-up period of 2 years, the valve remained functional in 130 (76.9%) of 169 patients. One hundred eight of these patients (63.9%) had an uncomplicated clinical course without any subsequent surgery, and 22 (13%) were submitted to a valve-preserving catheter revision without any further complications during the follow-up period. Thirty-nine patients (23.1%) reached an end point of valve explantation: 13 valve failures from infection (7.7%), 8 (4.7%) from overdrainage, and 18 (10.6%) from underdrainage.

Conclusions
Compared with nongravitational shunt designs, a GAV does not substantially affect the early complication rate. Valve-preserving shunt revisions do not increase the risk of subsequent valve failure and therefore should not be defined as an end point in studies on valve design. A significant impact of any well-established valve design on the early complication rate in shunt surgery is not supported by any current data; therefore, this correlation should be dismissed. As overdrainage-related complications have been shown to occur late, the presumed advantages of a pediatric GAV remain to be shown in a long-term study.
Role of Rac1-regulated signaling in medulloblastoma invasion
Authors: Zavarella Salvatore , Nakada Mitsutoshi , Belverud Shawn , Coniglio Salvatore J. , Chan Amanda , Mittler Mark A. , Schneider Steven J. , Symons Marc 
Published: September 2009

Object
Medulloblastomas are the most common malignant brain tumors in children. These tumors are highly invasive, and patients harboring these lesions are frequently diagnosed with distant spread. In this study, the authors investigated the role of Rac1, a member of the Rho family of small guanosine triphosphatases, in medulloblastoma invasion.

Methods
Three established medulloblastoma cell lines were used: DAOY, UW-228, and ONS-76. Specific depletion of Rac1 protein was accomplished by transient transfection of small interfering RNA. Cell invasion through extracellular matrix (Matrigel) was quantified using a transwell migration assay. Mitogen activated protein kinase activation was determined using phospho-MAP kinase–specific antibodies, and inhibition of MAP kinase pathways was achieved by specific small molecule inhibitors. Localization of Rac1 and its expression levels were determined by immunohistochemical analysis using a Rac1-specific antibody, and Rac1 activation was qualitatively assessed by Rac1 plasma membrane association.

Results
Small interfering RNA–mediated depletion of Rac1 strongly inhibited medulloblastoma cell invasion. Although depletion of Rac1 inhibited the proliferation of UW-228 cells, and of ONS-76 cells to a lesser extent, it stimulated the proliferation of DAOY cells. Depletion of Rac1 also inhibited the activation of the ERK and JNK MAP kinase pathways, and inhibition of either pathway diminished invasion and proliferation. Immunohistochemical analysis demonstrated that the Rac1 protein was overexpressed in all medulloblastoma tumors examined, and indicated that Rac1 was hyperactive in 6 of 25 tumors.

Conclusions
The authors' data show that Rac1 is necessary for the invasive behavior of medulloblastoma cells in vitro, and plays a variable role in medulloblastoma cell proliferation. In addition, these results indicate that Rac1 stimulates medulloblastoma invasion by activating the ERK and JNK pathways. The authors suggest that Rac1 and signaling elements controlled by this guanosine triphosphatase may serve as novel targets for therapeutic intervention in malignant medulloblastomas.