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Highlights • The B cell receptor (BCR) mediates the processing and presentation of cognate foreign antigen. • Ubiquitination of the BCR controls its trafficking to and within intracellular antigen processing compartments. • BCR-mediated antigen processing results in formation of peptide-class II complexes with unique biological/immunological properties. Abstract MHC class II-restricted antigen presentation by dendritic cells is necessary for activation of naïve CD4 T cells, whereas class II-restricted antigen presentation by B lymphocytes and macrophages is important for the recruitment of CD4+ helper and regulatory T cells. Antigen presentation by B cells is also important for induction of T cell tolerance. B cells are unique among these three types of MHC class II-expressing antigen presenting cells (APC) as they constitutively express high levels of cell surface class II molecules and express a clonally restricted antigen specific receptor, the B cell receptor (BCR). Here, I review our current understanding of three major steps that underlie the processing and presentation of BCR-bound cognate antigen: (1) endocytosis of antigen-BCR (Ag-BCR) complexes, (2) Ag-BCR trafficking to intracellular antigen processing compartments and (3) generation of antigenic peptide-MHC class II complexes, with a particular focus on the role of BCR ubiquitination in each. I will highlight potential topics for future research and briefly discuss the impact of the cell biology of BCR-mediated antigen processing on the response of the B cell and T cell to the cell-cell interactions mediated by B cell-expressed peptide-class II complexes. [ABSTRACT FROM AUTHOR]

Background: Safe robot-assisted intervention using magnetic resonance imaging (MRI) guidance requires the precise control of assistive devices, and most currently available tools are rarely MRI-compatible. To obtain high precision, it is necessary to characterize and develop existing MRI-safe actuators for use in a high magnetic field (≥3 T). Although an ultrasonic motor (USM) is considered to be an MRI-safe actuator, and can be used in the vicinity of a high field scanner, its presence interferes with MR images. Although an MR image provides valuable information regarding the pathology of a patient's body, noise, generally of a granular type, decreases the quality of the image and jeopardizes the true evaluation of any existing pathological issues. An eddy current induced in the conductor material of the motor structure can be a source of noise when the motor is close to the isocenter of the image. We aimed to assess the effects of a USM on the signal-to-noise ratio (SNR) of MR images in a 3-T scanner. The SNR was compared for four image sequences in transverse directions for three orientations of the motor (x, y, and z) when the motor was in the "off" state. The SNR was evaluated to assess three artifact reduction methods used to minimize the motor-induced artifacts.Results: The SNR had a range of 5-10 dB for slices close to the motor in the x and y orientations, and increased to 15-20 dB for slices far from the motor. Averaging the SNR for slices in all cases gave an SNR loss of about 10 dB. The maximum SNR was measured in the z orientation. In this case, the SNR loss was almost the same as that of other motor orientations, approximately 10 dB, but with a higher range, approximately 20-40 dB.Conclusions: The selection of certain scanning parameters is necessary for reducing motor-generated artifacts. These parameters include slice selection and bandwidth. In developing any MRI-compatible assisted device actuated by a USM, this study recommends the use of an approximately 3-mm slice thickness with minimum bandwidth to achieve optimized SNR values when a USM is operating close to (within approximately 40 mm) the region being imaged. The SNR can be further enhanced by increasing the number of signal averages, but this is achieved only at the cost of increased scan duration. [ABSTRACT FROM AUTHOR]

Heterotopic ossification (HO) is the pathologic formation of bone separate from the normal skeleton. Although several models exist for studying HO, an understanding of the common in vitro properties of cells isolated from these models is lacking. We studied three separate animal models of HO including two models of trauma-induced HO and one model of genetic HO, and human HO specimens, to characterize the properties of cells derived from tissue containing pre-and mature ectopic bone in relation to analogous mesenchymal cell populations or osteoblasts obtained from normal muscle tissue. We found that when cultured in vitro, cells isolated from the trauma sites in two distinct models exhibited increased osteogenic differentiation when compared to cells isolated from uninjured controls. Furthermore, osteoblasts isolated from heterotopic bone in a genetic model of HO also exhibited increased osteogenic differentiation when compared with normal osteoblasts. Finally, osteoblasts derived from mature heterotopic bone obtained from human patients exhibited increased osteogenic differentiation when compared with normal bone from the same patients. These findings demonstrate that across models, cells derived from tissues forming heterotopic ossification exhibit increased osteogenic differentiation when compared with either normal tissues or osteoblasts. These cell types can be used in the future for in vitro investigations for drug screening purposes. [ABSTRACT FROM AUTHOR]

MHC class II molecules present antigen-derived peptides to CD4T cells to drive the adaptive immune response. Previous work has established that class II αβ dimers can adopt two distinct conformations, driven by the differential pairing of transmembrane domain GxxxG dimerization motifs. These class II conformers differ in their ability to be loaded with antigen-derived peptide and to effectively engage CD4 T cells. Motif 1 (M1) paired I-A k class II molecules are efficiently loaded with peptides derived from the processing of B cell receptor-bound antigen, have unique B cell signaling properties and high T cell stimulation activity. The 11-5.2 mAb selectively binds M1 paired I-A k class II molecules. However, the molecular determinants of 11-5.2 binding are currently unclear. Here, we report the ability of a human class II transmembrane domain to drive both M1 and M2 class II conformer formation. Protease sensitivity analysis further strengthens the idea that there are conformational differences between the extracellular domains of M1 and M2 paired class II. Finally, MHC class II chain alignments and site directed mutagenesis reveals a triad of molecular regions that contributes to 11-5.2 mAb binding. In addition to transmembrane GxxxG motif domain pairing, 11-5.2 binding is influenced directly by α chain residue Glu-71 and in directly by the region around the inter-chain salt bridge formed by α chain Arg-52 and β chain Glu-86. These findings provide insight into the complexity of 11-5.2 mAb recognition of the M1 paired I-A k class II conformer and further highlight the molecular heterogeneity of peptide-MHC class II complexes that drive T cell antigen recognition. [ABSTRACT FROM AUTHOR]

This article traces the process by which people in the United States embraced the Continental Divide as a geographic feature of North America in the late 1860s. Building on recent work in environmental history, Civil War memory, geography, and the history of nationalism, the essay explains how accurate mapping alone did not reveal the Continental Divide. Instead, the divide's conceptualization also depended on Americans' history of thinking about the Rockies as a political boundary, southern secession, and the building of the transcontinental railroad. Many Americans found in that railroad's construction solace for a nation recovering from the Civil War, and they cast themselves as conquering nature to unite the nation. Railroad boosters and passengers consecrated the Continental Divide as a symbol of national unity and an icon o f obstacles overcome. In a nation trying to overcome its sectional division between North and South, aspirations for reunification formed a foundation for emphasizing the continent's most prominent feature that separates East and West. [ABSTRACT FROM AUTHOR]

Mesoscale forecasts for the Los Angeles basin made with the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) exhibited a moderate to substantial warm temperature bias for extended periods in the summer months. A similar bias also was thought to exist in forecasts made using version 2.2 of the Weather Research and Forecasting Model (WRF v2.2). To address these biases, two sources of anthropogenic moisture were analyzed: commercial irrigation and outdoor domestic water use. These represent substantial amounts of equivalent precipitation that are not accounted for in normal WRF execution. This is especially true for the summer months when little or no precipitation occurs in the area. A method for estimating the temporal and spatial distributions of these two sources was developed and the resulting database was applied to model runs. The addition of these anthropogenic moisture sources is an important source of enthalpy, which results in significant cooling in WRF. However, in the course of the analysis it was determined that the biases in WRF were much smaller than had been thought. Also, despite producing significant cooling, the addition of anthropogenic moisture made only modest improvements in forecast skill, and only for some hours of the day, indicating that more research is necessary on how the physical processes are handled in WRF, and how the anthropogenic moisture is distributed during the forecast period. [ABSTRACT FROM AUTHOR]

Complex spinal deformity (CSD) problems in pediatric patients result from a wide variety of congenital, acquired, neoplastic, or traumatic abnormalities that result in a combination of spinal deformity and spinal cord impingement. While these problems are rare, decompression, correction, instrumentation, and fusion are quite hazardous. Intraoperative neurophysiological monitoring (IONM) seems particularly beneficial in these patients. Somatosensory evoked potentials, transcranial electrical motor evoked potentials (MEPs), direct waves, and electromyography were used in a variety of CSD cases over a period when IONM was routine for most spinal cases. Examples of cases in which IONM provided important intraoperative information and significantly affected the course of the operation are illustrated. IONM is a useful tool particularly in CSD cases in pediatric patients but requires special expertise and anesthetic considerations. Loss of MEP appears to have particularly important adverse prognostic information. Conversely, maintenance of IONM provides significant reassurance that the spinal cord function is being maintained. Preserved but persistently diminished MEPs usually predict a neurological injury that will significantly improve and possibly completely recover. Issues concerning training, certification, oversight, standardization of equipment, and technique are partially but incompletely resolved. IONM is an extremely valuable tool for management of CSD pediatric patients. The utility of IONM is such and the detection of unexpected or unanticipated neurological injury frequent enough that a strong argument that it be used in every spinal surgery case can be made. [ABSTRACT FROM AUTHOR]

Lumbar puncture is a very common neurological diagnostic procedure which is associated with minimal risk. Epidural cerebrospinal fluid (CSF) collection can occur after puncture of the dura from extravasation of CSF from the thecal sac. On rare occasions, the epidural collection can be large enough to cause neurological dysfunction. The epidural fat has less fibrous stroma in children compared to adults, and it is postulated that this facilitates the dissection of CSF along epidural space. We report a rare case of a large symptomatic spinal epidural CSF collection shortly after lumbar puncture presenting with severe leg pain. The patient recovered fully within 48 h with bed rest and analgesia, and repeat imaging 1 month later showed good resolution of the epidural collection. Review of the literature revealed that epidural CSF collections resolve with conservative measures without the need for surgical intervention even in the setting of significant neurological symptomatology. [ABSTRACT FROM AUTHOR]

The article provides information on nosocomial bacterial meningitis. There are several factors that may lead to such disease including metastatic infection, head trauma, and invasive procedures. Patients who undergo craniotomy face the risk of bacterial meningitis. There are times when such disease occurs a week after surgery or years after surgery. However, the efficiency of performing surgical techniques may minimize the risk of postoperative meningitis. Information on the association of meningitis with internal ventricular catheters is also presented.

Uncertainty persists on the best treatment for patients with obstructive hydrocephalus: endoscopic third ventriculostomy (ETV) or shunt, particularly in the younger age groups. We performed decision analysis for quality of life (QOL) outcomes comparing these two procedures. Frequency of outcome events for ETV was obtained from the Canadian Pediatric Neurosurgery Study Group (368 patients) and for shunts from two prospective randomized trials, the Shunt Design Trial and the Endoscopic Shunt Insertion Trial (647 patients combined). Quality-adjusted life year (QALY) estimates for various outcomes were obtained from the literature. Decision analysis was performed at 1 year of follow-up for specific age groups, e.g., <1 month, 1–6 months, etc. Failure from cerebrospinal fluid (CSF) diversion from either procedure was a function of age with higher failures rates in younger patients. Expected QALY at 1 year were marginally higher for ETV for all age groups, but the outcomes were similar enough to be regarded as equivalent. The results, however, were highly sensitive to the assigned health utility value estimates for patients who are well with a functioning ETV or shunt and the severe complication rate from ETV. Age is a major determinant of outcome from CSF diversion with worse outcomes in young patients. QALY estimates for either ETV or shunt are similar at 1 year. [ABSTRACT FROM AUTHOR]

Background: Presurgical functional mapping using magnetoencephalography (MEG) has been performed for somatosensory, auditory and visual functions; however, the traditional analysis method utilizing dipole source analysis has some inherent limitations when applied to the mapping of cortical motor areas. Recently, a novel source reconstruction algorithm [event-related synthetic aperture magnetometry (erSAM)] has demonstrated success for the localization of motor function in healthy adults. We applied this technique to preoperatively map motor function in a young patient. We then confirmed our mapping with direct cortical stimulation intraoperatively. Methods: This is a case report of an 8-year-old girl with right hand and arm weakness and poor right hand motor control secondary to a left peri-rolandic tumor. Preoperatively, whole-head MEG was recorded while the patient performed a self-paced button pressing task. Cortical activity associated with the onset of movement was localized to the right hand precentral gyrus superior and medial to the tumor using erSAM, while sensory function was localized posterior to the tumor on the postcentral gyrus. Results: Intraoperative direct cortical stimulation of the motor area identified by MEG resulted in electromyographic activation of intrinsic muscles of the contralateral hand exclusively. Conclusions: This is the first report of a case where direct cortical stimulation has confirmed a motor cortical location identified by the erSAM method. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: The virulence of Francisella tularensis LVS is determined in part by its ability to invade and replicate within macrophages and stimulate the production of inflammatory cytokines. The present study determined the effects of growing F. tularensis in macrophages on its ability to stimulate cytokine secretion by macrophages. F. tularensis grown in Mueller–Hinton broth (FtB) stimulated the secretion of large amounts of TNF-α, IL-12p40, IL-6 and MCP-1/CCL2 when incubated with macrophages overnight. In contrast, F. tularensis released from infected macrophages (FtMac) stimulated very little secretion of these cytokines by primary cultures of murine peritoneal macrophages, human monocytes or macrophage cell lines. Stimulation of nitric oxide production by FtMac was also less than that elicited by FtB. FtMac killed with gentamicin or paraformaldehyde also stimulated low levels of cytokine secretion. FtMac recovered the ability to stimulate cytokine secretion after overnight culture in broth. Infection of macrophages with FtMac inhibited the cytokine response to subsequent stimulation with LPS from Escherichia coli but did not affect Fcγ receptor-mediated phagocytosis. FtMac were ingested by macrophages at about half the rate of FtB, however, this did not account for the lower cytokine secretion. FtMac and FtB replicated at similar rates within macrophages. Finally, Mice infected with FtMac had a higher mortality rate than those infected with FtB. These results reveal that growth in macrophages causes a reversible phenotypic change in F. tularensis that is associated with decreased stimulation of cytokine secretion, inhibition of LPS-stimulated secretion of inflammatory cytokines by macrophages and increased lethality in mice. [Copyright &y& Elsevier]

Argues that laboratory studies are more capable in capturing essential dynamics of ecological systems compared with field studies. Limitations of laboratory studies; Concepts in community ecology; Aspects of ecology that require the use of laboratory studies to understand its ecological phenomena; Difference between laboratory studies and field studies; Role of laboratory microcosms in ecological research.

Non-traumatic atlanto-axial subluxation (Grisel's syndrome) is an uncommon complication of neck space infection or otolaryngologic procedures. It most frequently affects children, although it may occur in adults. We present a 14-year-old boy with Grisel's syndrome as a complication of infectious mononucleosis proceeding to cervical ankylosis. [ABSTRACT FROM AUTHOR]

Focuses on the trends in science on both sides of the Atlantic that made it possible for colonists to perceive themselves as a part of a natural geographic entity, and how these trends thus shaped Anglo-Americans' sense of political destiny. Exploration of the work of eighteenth-century geographers and how it related to contemporary political theories; Documentation of how changing theories of climate and race reinforced Anglo-American views of continents as natural units; Constraints of latitudinal determinism.

An 8-year-old boy with an implanted intrathecal baclofen pump presented with intermittent signs of baclofen under- and overdose. Pump interrogation, pump volumes, plain X-rays, catheter contrast fluoroscopy and CT of the intrathecal catheter tip were unremarkable. A microfracture of the extradural catheter was only seen at a magnification of !20 and confirmed by scanning electron microscopy. Symptoms resolved following replacement. Microfracture of the intrathecal catheter of baclofen pump systems may present puzzling symptomatology and be difficult to diagnose by conventional means. [ABSTRACT FROM AUTHOR]

Objective: Brachial plexus injury complicates 0.6–2.6 per 1,000 live births. Surgery is sometimes advocated for patients who fail to improve with conservative management. We reviewed the available literature on birth-related brachial plexus palsy in order to provide recommendations for surgical management, using evidence-based criteria. Methods: Studies were identified by searc hing Medline (1966–2002) and the Cochrane Library using the terms brachial plexus, neonate or infant, surgery and natural history. The reference lists of relevant articles were also reviewed. The search was restricted to articles published in English. Each article was classified according to its methodology. Management recommendations were suggested based on the results of the studies identified and the degree of certainty of the available literature. Results: Twenty-three papers were selected for detailed analysis. There are no randomized controlled trials that have investigated the role of brachial plexus surgery in the management of birth-related brachial plexus palsy. Two prospective studies of relevance were found, one describing the natural history of birth-related brachial plexus injury and one evaluating surgery for these patients. The remainder consisted of retrospective case series. Outcomes from surgical series are generally favorable (level III and V evidence). Direct comparison with the natural history could not be inferred from the series reviewed given the lack of controls. Conclusion: There is no conclusive evidence showing a benefit of surgery over conservative management approaches in the treatment of patients with birth-related brachial plexus injuries. Surgery remains a valid practice option given the level III and V evidence suggesting a possible benefit of surgery.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

This work aims at quantifying the minimum utility cost necessary to complete a given separation task using vapor–liquid equilibrium (distillation) operations. The Infinite DimEnsionAl State-space (IDEAS) process is introduced as a new paradigm for this process synthesis activity. The IDEAS conceptual framework includes all possible process configurations, and yields mathematical programs that are convex (linear), thereby guaranteeing the global optimality of the obtained solution.A case study, on nitrogen/oxygen mixture separation, is employed to illustrate the power of the proposed approach. The obtained IDEAS designs are compared with the corresponding McCabe–Thiele (conventional) minimum utility designs, and are shown to be as much as 50% more thermodynamically and economically efficient. [Copyright &y& Elsevier]

Traces the so-called science wars of the postmodernist period to an essay by Roman Jacobson on aphasia. Deconstructionist philosopher Jacques Derrida's suggestion that science was mythology; Incorporation of the theories of Jakobson into the humanities; Distortions of Kurt Goldstein as bases of poststructuralist and postmodernist theories.

Reviews the music recording 'Rosa Ponselle on the Air.'

Isolated axillary nerve injury is uncommon, particularly in children. The motor deficit of shoulder abduction may not recover spontaneously and can be a substantial handicap. Detection may be difficult initially, as the injury is masked by trauma such as head injury, and concomitant shoulder injury requiring immobilization. After mobilization, patients learn to partially compensate by using alternate muscles. There are few reports of surgical management of this nerve injury. Most concern predominantly adults, and the results are mixed with on average slightly greater than half having a good recovery (defined as grade 4–5 Medical Research Council muscle power). We present our experience with 4 pediatric patients who had axillary nerve injury. Three patients had an interposition nerve graft, and 1 patient underwent neurolysis. All patients recovered to grade 4–5 deltoid muscle power. Children with an axillary nerve injury which fails to recover spontaneously by 4–6 months should strongly be considered for surgical exploration.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Ewing’s sarcoma (ES) of the skull is rare. Herein, we present 2 cases of ES that involved the cranium in young children. In one case, the lesion originated in the petrous temporal bone; in the other, the frontal bone. Both children were acutely compromised neurologically by signs and symptoms of raised intracranial pressure. In both cases, radiographs revealed massive tumors affecting the skull. Neurosurgical resection of the tumor was undertaken in both instances, and the diagnosis of ES was confirmed by immunohistochemistry, cytogenetic analysis (translocation 11;22), spectral karyotyping and RT-PCR (demonstration of a EWS/FLI1 fusion transcript). Following aggressive surgical resection, both children received intensive chemotherapy. No child has received radiation therapy. One child is alive and well 8 years after diagnosis without any evidence of residual disease. The other is currently undergoing chemotherapy for her tumor. The principles involved in the management of children with cranial-based ES are discussed. These 2 cases serve to illustrate the fact that even children with massive ES tumors of the cranium may be salvaged with aggressive combination therapy.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Introduction: The frontal and occipital horn ration (FOR) has recently been described as a simple, linear measurement of ventricular size that correlates very well with ventricular volume. This study further characterizes the measurement properties of the FOR by investigating its interobserver reliability and comparing it to a subjective assessment of ventricular size. Methods: Axial images (CT and MR) of children with hydrocephalus taken before and after third ventriculostomy were reviewed by 4 independent observers. Two observers were blinded to patient identity and clinical status and 2 observers were nonblinded. Each observer independently recorded linear measurements from which the FOR was calculated for each image. Each reviewer also made a separate subjective assessment of the degree of hydrocephalus on a 9-point adjectival scale. Reliability was calculated using a repeated-measures analysis of variance (ANOVA) and an intraclass correlation coefficient (ICC) with random image and observer effects. Results: There were 120 separate observations (4 observers, 30 images). The FOR ranged from 0.33 to 0.75 (mean 0.55, standard deviation 0.11). The reliability coefficient was 0.93 (95% confidence interval, CI 0.80–0.97) between the 2 blinded observers and 0.98 (95% CI, 0.95–0.99) between the 2 nonblinded observer. The overall interobserver reliability for all 4 observers was 0.95 (95% CI 0.92–0.98). The mean FOR for each observer was very similar, regardless of the observer’s blinding status. However, the reliability of the observers’ subjective assessment of the hydrocephalus was much lower (ICC = 0.77, 95% CI 0.60–0.88). Conclusions: The FOR demonstrates excellent interobserver reliability (>0.9) and was superior to subjective assessments of hydrocephalus. In this study, excellent reliability was maintained regardless of the blinding status of the observers. This further demonstrates the properties of the FOR as a simple and reproducible measure of ventricular size. It is suitable for use in clinical studies, possibly even in situations in which observer blinding is not possible.Copyright © 1999 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Previews the first chapter entitled `The Arrival of Lily Pons,' from the book `Lily Pons: A Centennial Portrait,' by James A. Drake and Kristin Beall Ludecke, about the life and career of Italian singer, Lily Pons.

Discusses the war brutalities committed under King Philip of New England in 1675-1676. Citation of the Pequot War of 1637; Background on King Philip Vincent; Historic evaluation of King Philips' war; Contextual comparison with war with the Americas involving English Puritans.

Examines the relationship between career maturity levels and age of incarcerated juvenile in the United States. Factors affecting career maturity; Statistics on youth-committed crimes; Definition of expressed vocational interest; Consideration of career education and counseling programs for incarcerated juvenile.

Reports on the discovery of a population of major histocompatibility complex class II-enriched vesicles (CIIV) in B lymphocytes distinct from endosomes and lysosomes that accumulate internalized antigen. Organelles in class II transport; CIIV as part of the endocytic pathway; CIIV and alpha/beta dimer transport; Peptide-loaded alpha/beta dimers in CIIV.

Objective: Measurement of ventricular size is important in pediatric patients with hydrocephalus, especially those who are being followed with cerebrospinal fluid (CSF) shunts. While volumetric techniques are a more accurate estimate of true ventricular volume, they are often impracticable when multiple modalities including ultrasound are used. Volumetric area and linear measurements were compared to find the most reasonable measurement method. Methods: Sixty-four computed tomography (CT), magnetic reasonance imaging (MRI), and ultrasound (US) scans from 25 children aged 0–17 years with hydrocephalus, before and after treatment, were measured. Measurements included ventricular volume, a ventricular/brain ratio, and four standard linear measures (Evans’ ratio, Huckman’s measurement, minimal lateral ventricular width, and lateral ventricular span at the body). We also included a new ratio, which accounts for often disproportionate occipital horn expansion in pediatric patients, called the frontal and occipital horn ratio. Volume and linear measurements were compared using the Spearman’s correlation coefficients and correlations were further differentiated using a Z test statistic. The frontal and occipital horn ratio was also measured on CT, MRI, and US scans from 44 normal children aged 0–17 years to identify normal values. The effect of age was determined by linear regression. Results: The best linear correlation with ventricular size was the frontal + occipital horn ratio (r = 0.852) and was equivalent to the ventricular/brain ratio (r = 0.891), previously shown to have the highest correlation with ventricular volume. Evans’ ratio correlates less well (r = 0.423). The normal frontal and occipital horn ratio is 0.37 and is independent of age. Conclusions: The frontal and occipital horn ratio is a simple method of evaluating ventricular size in pediatric hydrocephalus patients with CSF shunts. [ABSTRACT FROM AUTHOR]

Presents information on microcosms as models for generating and testing community theory. Details on biological models in ecological research; Description of the ecological community; Details on invasion resistance; Information on community self-organization.

Reviews the music recording `L'elisir d'amore.'

Reviews the music recording `Rosa Ponselle: The 1939 Victor and 1954 `Villa Pace' Recordings.'

Presents an excerpt from the author's book entitled `Rosa Ponselle: A Centenery Biography.'

Reviews the music recording `Silvano,' by Pietro Mascagni.

Interviews Rosa Ponselle on her nineteen-year career with the Metropolitan Opera Company. Ponselle's recollections of her European performances during a series of interviews at her home in the mid-70s.

Purpose: Magnetic resonance (MR) imaging detection of methemoglobin, a molecular marker of intraplaque hemorrhage (IPH), in atherosclerotic plaque is a promising method of assessing stroke risk. However, the multicenter imaging studies required to further validate this technique necessitate the development of IPH phantoms to standardize images acquired across different scanners. This study developed a set of phantoms that modeled methemoglobin-laden IPH for use in MR image standardization.Procedures: A time-stable material mimicking the MR properties of methemoglobin in IPH was created by doping agarose hydrogel with gadolinium and sodium alginate. This material was used to create a phantom that consisted of 9 cylindrical IPH sites (with sizes from 1 to 8 mm). Anatomical replicas of IPH-positive atherosclerosis were also created using 3D printed molds. These plaque replicas also modeled other common plaque components including a lipid core and atheroma cap. T1 mapping and a magnetization-prepared rapid acquisition gradient echo (MPRAGE) carotid imaging protocol were used to assess phantom realism and long-term stability.Results: Cylindrical phantom IPH sites possessed a T1 time of 335 ± 51 ms and exhibited little change in size or MPRAGE signal intensity over 31 days; the mean (SD) magnitude of changes in size and signal were 6.4 % (2.7 %) and 7.3 % (6.7 %), respectively. IPH sites incorporated into complex anatomical plaque phantoms exhibited contrast comparable to clinical images.Conclusions: The cylindrical IPH phantom accurately modeled the short T1 time characteristic of methemoglobin-laden IPH, with the IPH sites exhibiting little variation in imaging properties over 31 days. Furthermore, MPRAGE images of the anatomical atherosclerosis replicas closely matched those of clinical plaques. In combination, these phantoms will allow for IPH imaging protocol standardization and thus facilitate future multicenter IPH imaging. [ABSTRACT FROM AUTHOR]

Introduction: Pediatric hemispherectomy is a technically demanding procedure with significant risk. There are relatively few opportunities for surgeon trainees to gain confidence in this nuanced surgery solely through traditional apprenticeship prior to independent practice. Surgeon confidence has been linked to better intraoperative performance and surgical simulation has, according to literature, resulted in improved surgeon confidence. This manuscript measures the effect of epilepsy simulation on the procedural confidence of neurosurgical trainees as a marker of future improved intraoperative performance. Methods: Eleven neurosurgery residents and fellows were allowed to practice on a novel hemispherectomy simulator. Pre- and post-simulation procedural confidence was measured using a 10-item questionnaire, with total scores ranging from 10 (least confident) to 50 (most confident). Matched pair t-testing was performed to determine participant mean difference between the pre- and post-procedural data sets. Results: The assessment tool bore a high reliability coefficient (Cronbach's α = 0.93). The procedural confidence of all the study participants increased following simulation (p value < 0.001). The overall mean increase in confidence was 7.2 ± 4.0 (mean ± standard deviation), 7.5 ± 4.7 among fellows and 6.8 ± 3.6 among residents. Procedural confidence values were higher among the fellows (26.9 ± 8.1) compared to the residents (19.0 ± 7.4). This difference in means was statistically significant (p value 0.03). A positive association was calculated between the perceived confidence and the postgraduate year of training (p value 0.005, r = 0.57). Conclusion: The hemispherectomy simulator moderately improves perceived confidence among neurosurgical trainees and may augment pre-operative surgical practice opportunities. [ABSTRACT FROM AUTHOR]

A response by Diederik van de Beek, James M. Drake and Allan R. Tunkel to a letter to the editor about their article "Nosocomial Bacterial Meningitis" in a 2010 issue is presented.

Outcomes following vagus nerve stimulation (VNS) improve over years after implantation in children with drug‐resistant epilepsy. The added value of deep brain stimulation (DBS) instead of continued VNS optimization is unknown. In a prospective, non‐blinded, randomized patient preference trial of 18 children (aged 8–17 years) who did not respond to VNS after at least 1 year, add‐on DBS resulted in greater seizure reduction compared with an additional year of VNS optimization (51.9% vs. 12.3%, p = 0.047). Add‐on DBS also resulted in less bothersome seizures (p = 0.03), but no change in quality of life. DBS may be considered earlier for childhood epilepsy after non‐response to VNS. ANN NEUROL 2024;96:405–411 [ABSTRACT FROM AUTHOR]

We report a rare regime of Earth's magnetosphere interaction with sub‐Alfvénic solar wind in which the windsock‐like magnetosphere transforms into one with Alfvén wings. In the magnetic cloud of a Coronal Mass Ejection (CME) on 24 April 2023, NASA's Magnetospheric Multiscale mission distinguishes the following features: (a) unshocked and accelerated low‐beta CME plasma coming directly against Earth's dayside magnetosphere; (b) dynamical wing filaments representing new channels of magnetic connection between the magnetosphere and foot points of the Sun's erupted flux rope; (c) cold CME ions observed with energized counter‐streaming electrons, evidence of CME plasma captured due to by reconnection between magnetic‐cloud and Alfvén‐wing field lines. The reported measurements advance our knowledge of CME interaction with planetary magnetospheres, and open new opportunities to understand how sub‐Alfvénic plasma flows impact astrophysical bodies such as Mercury, moons of Jupiter, and exoplanets close to their host stars. Plain Language Summary: Like supersonically fast fighter jets creating sonic shocks in the air, planet Earth typically moves in the magnetized solar wind at super‐Alfvénic speeds and generates a bow shock. Here we report unprecedented observations of Earth's magnetosphere interacting with a sub‐Alfvénic solar wind brought by an erupted magnetic flux rope from the Sun, called a coronal mass ejection (CME). The terrestrial bow shock disappears, leaving the magnetosphere exposed directly to the cold CME plasma and the strong magnetic field from the Sun's corona. Our results show that the magnetosphere transforms from its typical windsock‐like configuration to having wings that magnetically connect our planet to the Sun. The wings are highways for Earth's plasma to be lost to the Sun, and for the plasma from the foot points of the Sun's erupted flux rope to access Earth's ionosphere. Our work indicates highly dynamic generation and interaction of the wing filaments, shedding new light on how sub‐Alfvénic plasma wind may impact astrophysical bodies in our solar and other stellar systems. Key Points: MMS observed a rare regime of magnetosphere interaction with unshocked low‐beta CME plasmaWing filaments represent dynamical channels of magnetic connection between the magnetosphere and foot points of the Sun's erupted flux ropeCold CME ions observed on closed field lines, likely generated by dual‐wing reconnection [ABSTRACT FROM AUTHOR]

Introduction: Magnetic resonance-guided focused ultrasound (MRgFUS) has been demonstrated to be able to thermally ablate tendons with the aim to non-invasively disrupt tendon contractures in the clinical setting. However, the biomechanical changes of tendons permitting this disrupting is poorly understood. We aim to obtain a dose-dependent biomechanical response of tendons following magnetic resonance-guided focused ultrasound (MRgFUS) thermal ablation. Methods: Ex vivo porcine tendons (n = 72) were embedded in an agar phantom and randomly assigned to 12 groups based on MRgFUS treatment. The treatment time was 10, 20, or 30s, and the applied acoustic power was 25, 50, 75, or 100W. Following each MRgFUS treatment, tendons underwent biomechanical tensile testing on an Instron machine, which calculated stress-strain curves during tendon elongation. Rupture rate, maximum treatment temperature, Young's modulus and ultimate strength were analyzed for each treatment energy. Results: The study revealed a dose-dependent response, with tendons rupturing in over 50% of cases when energy delivery exceeded 1000J and 100% disruption at energy levels beyond 2000J. The achieved temperatures during MRgFUS were directly proportional to energy delivery. The highest recorded temperature was 56.8°C ± 9.34 (3000J), while the lowest recorded temperate was 18.6°C ± 0.6 (control). The Young's modulus was highest in the control group (47.3 MPa ± 6.5) and lowest in the 3000J group (13.2 MPa ± 5.9). There was no statistically significant difference in ultimate strength between treatment groups. Conclusion: This study establishes crucial thresholds for reliable and repeatable disruption of tendons, laying the groundwork for future in vivo optimization. The findings prompt further exploration of MRgFUS as a non-invasive modality for tendon disruption, offering hope for improved outcomes in patients with musculotendinous contractures. [ABSTRACT FROM AUTHOR]

The article offers information on several people who served at the Hospital for Sick Children in Toronto, Ontario. It mentions that the neurosurgery service of the hospital begun with the appointment of neurosurgeon William S. Keith in 1933. It says that E. Bruce Hendrick joined Keith in 1954 after he had obtained an specialty training in pediatric neurosurgery in Boston, Massachusetts. It states that Harold J. Hoffman was appointed as neurosurgical staff at Sick Kids in 1964.

Discusses magnetic storms in the magnetic field that surrounds Earth. Interference caused by the storms to satellite communications; Creation of magnetic fields in dynamo of ionized gases; Questions concerning the rate of the release of magnetic energy; Theory of magnetic reconnection.