bluuebunny/crossref_metadata_2025_split huggingface dataset:
One Laptop per Child: The $100 Challenge
Authors: Roberts Andrea Alston , Zamora Valentina L. 
Published: March 2012

ABSTRACT
This case uses a real organization (One Laptop per Child, or OLPC) that is unique in that it reengineered laptops that can be produced at low cost, outsourced manufacturing to a Taiwanese corporation, and sold to governments of developing nations that in turn distributed them to local school children. The purpose of this case is to provide instructors an unstructured case to help students apply cost accounting concepts, tools, and techniques to a real-world, social enterprise organization. We recommend this case for use by instructors in cost accounting courses. In this case, students will have the opportunity to use publicly available managerial accounting information. Depending on the instructor's preferences and the course learning objectives, students may be exposed to a variety of case questions, some of which require application of more technical skills such as breakeven calculations, and some of which require more analytical skills such as cost structure considerations.
Feedback from students suggests that the case positively impacts their learning along several dimensions of managerial cost accounting. Various instructors have successfully used this case in the upper-level cost accounting and the graduate-level managerial accounting core courses as an opportunity for students to develop skills critical for today's business professional.
Monte Carlo analysis of polymer translocation with deterministic and noisy electric fields
Authors: Valenti Davide , Denaro Giovanni , Adorno Dominique , Pizzolato Nicola , Zammito Salvatore , Spagnolo Bernardo 
Published: March 2012

AbstractPolymer translocation through the nanochannel is studied by means of a Monte Carlo approach, in the presence of a static or oscillating external electric voltage. The polymer is described as a chain molecule according to the two-dimensional “bond fluctuation model”. It moves through a piecewise linear channel, which mimics a nanopore in a biological membrane. The monomers of the chain interact with the walls of the channel, modelled as a reflecting barrier. We analyze the polymer dynamics, concentrating on the translocation time through the channel, when an external electric field is applied. By introducing a source of coloured noise, we analyze the effect of correlated random fluctuations on the polymer translocation dynamics.
Deltoid Ligament Abnormalities in Chronic Lateral Ankle Instability
Authors: Crim Julia R. , Beals Timothy C. , Nickisch Florian , Schannen Andrew , Saltzman Charles L. 
Published: March 2012

Background: Treatment of patients with repeated ankle sprains and chronic lateral ankle instability tends to focus on the lateral collateral ligaments. We reviewed records to ascertain the prevalence of abnormalities of the deltoid ligament in this population. Methods: Retrospective review of MR images and surgical reports was performed for all patients during a 3-year period that underwent surgical treatment of chronic ankle instability at a single institution. Forty-seven ankles (46 patients) met inclusion criteria. None had medial ankle pain. Results: On MRI, all patients had anterior talofibular ligament tear, plus injury to one or more additional ligaments. Ninety-one percent had injury of calcaneofibular ligament. Injury to the posterior talofibular ligament was less common (49%). Deltoid ligament injuries were seen in 72% of cases (23% superficial deltoid only, 6% deep deltoid only, 43% both superficial and deep components). Of patients with injury to the superficial deltoid, 32% had an intact deep deltoid ligament. MRI correlated well to surgical findings. Conclusion: Deltoid ligament injuries were common in patients with lateral ankle instability who underwent reconstruction. Level of Evidence: IV, Retrospective Case Series
Total Ankle Replacement in Obese Patients: Component Stability, Weight Change, and Functional Outcome in 118 Consecutive Patients
Authors: Barg Alexej , Knupp Markus , Anderson Andrew E. , Hintermann Beat 
Published: March 2012

Background: Obesity is a growing problem in Europe and the United States. While obesity has been linked to poor outcomes after total knee or hip replacement, there are no data addressing outcomes in obese patients who underwent total ankle replacement (TAR). Methods: This retrospective chart review included 118 patients (123 ankles) with a minimum body mass index (BMI) of 30 kg/m2 who underwent TAR between May 2000 and June 2008. There were 61 male (51.7%) and 57 female (48.3%) patients with a mean age of 59.8 ± 11.6 years (range, 25.4 to 85.0). All patients were evaluated pre- and postoperatively (mean followup 67.7 ± 27.0 months; range, 29 to 126). Radiological outcomes were assessed using standardized weight-bearing radiographs. Clinical outcomes were assessed using the visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot scale. Results: There were nine intraoperative complications. All patients experienced significant pain relief (VAS change from 7.0 ± 1.7 to 1.4 ± 1.1, p < 0.001) and functional improvement (AOFAS score change from 35.4 ± 14.9 to 75.4 ± 9.6, p < 0.001; total ROM change from 26.9 ± 13.7 to 35.3 ± 8.1 degrees, p ± 0.001). BMI measured preoperatively, and at 1 and 2 years postoperatively was 32.9 ± 2.5 (range, 30.0 to 40.0) kg/m2, 32.4 ± 2.4 (range, 28.6 to 41.0) kg/m2, and 32.2 ± 2.4 (range, 28.6 to 40.5) kg/m2, respectively. Gender had a significant effect on weight loss, but not age or postoperative sports activity. Revision surgery was performed in six patients, resulting in a 6-year survivorship of 93%. Conclusion: Our findings confirm that TAR gives significant pain relief and functional improvement. In this study, the survivorship of the prosthesis components was comparable to the results obtained in non-obese patients. Level of Evidence: IV, Therapeutic Case Series
Long-Term Results Following Keller Resection Arthroplasty for Hallux Rigidus
Authors: Schneider Wolfgang , Kadnar Georg , Kranzl Andreas , Knahr Karl 
Published: March 2012

Background: We assessed the long-term results following Keller resection arthroplasty for the treatment of hallux rigidus. We then compared them with alternative surgical methods like cheilectomy, arthrodesis and joint replacement. Methods: Eighty-seven cases of Keller resection arthroplasty for hallux rigidus were reviewed with mean followup of 23 years. Their mean age at time of surgery was 50 years. Analysis included personal clinical evaluation with the AOFAS Hallux Score, quality-of-life assessment using the SF-36, radiographic assessment, pedobarographic evaluation and analysis of the patients' charts to detect any postoperative complications. Results: At the time of followup only five (5%) feet had undergone revision surgery. For all other cases we calculated a mean AOFAS score of 83 points. Sixty-nine of 73 unrevised patients (94%) would opt for this operation again under the same circumstances. SF-36 parameters showed age related normal values. Pedobarographic assessment revealed only moderate weightbearing alterations. Our long-term results compare favorably with published results following arthrodesis, cheilectomy or joint replacement for the treatment of painful hallux rigidus. Clinical results and subjective assessments were very good and complication rates were low compared to competing methods. Conclusion: Keller resection arthroplasty remains a valuable surgical option for the treatment of advanced stages of hallux rigidus with high patient satisfaction, moderate weightbearing alterations and comparable low complication rate in our experience. Level of Evidence: IV, Retrospective Case Series
Incidence of Osteochondral Lesions of the Talus in the United States Military
Authors: Orr Justin D. , Dawson Laura K. , Garcia E'Stephan J. , Kirk Kevin L. 
Published: March 2012

Background: Osteochondral lesion of the talus (OCLT) is frequently described as an uncommon diagnosis; however, little is known of its incidence. In light of increased awareness combined with the continued evolution of radiologic and treatment modalities, more attention has been given to this diagnosis. Serving a young, athletic population with unique occupational requirements, we have perceived an increase in the diagnosis of OCLTs. The goal of this study was to determine the incidence of OCLTs in an active duty military population, as well as demographic risk factors for OCLTs. Methods: We performed a query of the Defense Medical Epidemiology Database (DMED) of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code for OCLTs which in the Armed Forces Health Longitudinal Technology Application (AHLTA) system is uniquely assigned the code 732.5. An overall injury incidence was calculated, in addition to multivariate analysis to determine independent risk factors among the following demographic considerations: gender, race, rank, branch of military service, and age. Year of diagnosis was also considered. Results: The overall incidence rate for the 10-year period (1999 to 2008) was 27 OCLTs per 100,000 person-years. Significant demographic risk factors were female gender, white race, enlisted rank, service in the Army and Marines, and age greater than 20 years. Incidence rate was 16 per 100,000 in 2002, with steady annual increases resulting in an incidence rate of 56 per 100,000 person-years in 2008, corresponding to the years of active involvement in global combat operations. Conclusion: The incidence of OCLTs in the active duty military population was higher with female gender, white race, enlisted rank, increased age, and Army or Marine service. Level of Evidence: IV, Retrospective Series
Intraoperative Incidence of Hallux Valgus Interphalangeus Following Basilar First Metatarsal Osteotomy and Distal Soft Tissue Realignment
Authors: Park Jae-Yong , Jung Hong-Geun , Kim Tae-Hoon , Kang Min-Seok 
Published: March 2012

Background: The premise of this study was that after the correction of hallux-metatarsophalangeal pronation, the intra-operative interphalangeal angle (HIA) increases significantly, and that an additional Akin osteotomy (AO) is often needed. Therefore, the purpose of this study was to evaluate whether HIAs in hallux valgus (HV) feet were underestimated, and to assess the need for AO during HV correction. Method: This study was conducted on 54 feet with moderate to severe HV treated from June 2007 to December 2008. HIAs and medial sesamoid subluxations (MSS) were measured initially and intra-operatively after a distal soft tissue procedure (DSTP) and proximal chevron metatarsal osteotomy (PCMO). An intraoperative technique was used to evaluate the incongruency of the metatarsophalangeal joint (MTPJ) to determine the need for additional AO. Results: After performing DSTP and PCMO, HIAs significantly increased from an average of 9 to 13.3 degrees and MSS reduced from average grade 2.5 to 0.5 (p < 0.05). AO was added in 44 (81%) feet. After an average followup of 13.2 months in Akin group, average VAS pain score decreased from 5.7 to 1.2 and average AOFAS score increased from 57.8 to 90.2 ( p < 0.05). Final hallux MTPJ dorsiflexion in the Akin group was significantly larger than in the without-Akin group ( p < 0.05). Conclusion: Average HIA significantly increased after DSTP and PCMO for moderate to severe HV necessitating additional AO, to achieve ideal HV correction and, to preserve MTPJ motion. Level of Evidence: III, Retrospective Case Control Series
Supramalleolar Osteotomy Using Circular External Fixation with Six-Axis Deformity Correction of the Distal Tibia
Authors: Horn Daniel M. , Fragomen Austin T. , Rozbruch S. Robert 
Published: March 2012

Background: Supramalleolar osteotomy using circular external fixation with six-axis deformity correction is a rarely reported treatment method particularly well-suited for complex multidimensional deformities of the adult ankle. The purpose of this study was to assess the accuracy of deformity correction and change in functional status using this technique. Methods: We present a retrospective review of 52 patients who underwent supramalleolar osteotomy with application of the Taylor Spatial Frame (Smith & Nephew, Memphis, TN). Mean age was 44 (range, 18 to 79) years. The primary outcome was change in preoperative to postoperative distal tibial joint orientation angles. Coronal and sagittal plane joint orientation angles were measured for all 52 enrolled patients. The secondary outcome was change in AOFAS scores which were available for 31 patients. Results: Twenty-two patients had oblique plane deformities. The mean time in frame was 4 (range, 2 to 11) months, and patients were followed for a mean of 14 months after frame removal. All aggregate postoperative distal tibial angles underwent a significant improvement ( p < 0.05) and were within 0 degrees to 4 degrees of normal in the various deformity groups. Average preoperative AOFAS score was 40 (range, 12 to 67) and average postoperative AOFAS score was 71 (range, 34 to 97; p < 0.001). Complications included two patients with nonunions at the osteotomy site that healed with further treatment. Three patients went on to have ankle fusion. Conclusion: We feel that supramalleolar osteotomy using circular external fixation with six-axis deformity correction was an effective method for correction of distal tibial deformities in the adult population, particularly for those patients with complex oblique-plane deformities, associated rotational deformity, a compromised soft tissue envelope, or a prior history of infection. Level of Evidence: IV, Retrospective Case Series
Response of plant species to abandonment of subalpine fields, Manang, Nepal
Authors: Baniya Chitra Bahadur 
Published: March 2012

Spatial dimension of abandoned fields has been expanding more in rural subalpine zones of Nepal leading to various patterns of secondary succession. The secondary succession in the subalpine Himalayas has not yet been evaluated. Here, I describe a study initiated in Manang district, Central Nepal where enough abandoned fields of different chronosequences were located. A definitive successional pattern was predicted from the data obtained from sampling 256 plots of 1 × 1 m2 each systematically in a total of 43 abandoned fields from 1 to 55 years after abandonment. Change in composition pattern of 11 most important plant species was analyzed through the Detrended Correspondence Analysis (DCA). The first two axes of DCA explained 19.1 % of the total variation in the species composition. Early, mid and late successions were three stages distinguished each by their abundance scores and life-forms composition. Malva neglecta, Phleum alpinum and Fagopyrum esculentum were dominant at the recently abandoned fields. Cynoglossum zeylanicum, Malaxis muscifera, Medicago falcata and Pennisetum flaccidum were mid succession species, and Thymus linearis, Tanacetum gossypinum, Pinus wallichiana and Poa annua represented the late succession species.doi: http://dx.doi.org/10.3126/botor.v8i0.5553 Botanica Orientalis – Journal of Plant Science (2011) 8: 10-15
Caste, class, and the politics of personhood in neo-liberal India
Authors: Rao Anumpama 
Published: March 2012

Craig Jeffrey. Timepass: Youth, Class, and the Politics of Waiting. Stanford, CA: Stanford University
Press, 2010. vii + 221 pages.Manuela Ciotti. Retro-Modern: Forging the Low-Caste Self. London, New York, and New Delhi: Routledge,
2010. xvii + 292 pages.
Intractable epilepsy in paralimbic World Health Organization Grade II gliomas: should the hippocampus be resected when not invaded by the tumor?
Authors: Ghareeb Fadi , Duffau Hugues 
Published: March 2012

Object
Beyond its oncological benefit, surgery could improve seizure control in paralimbic frontotemporoinsular or temporoinsular WHO Grade II gliomas generating intractable seizures. However, no studies have examined the impact of hippocampal resection on chronic epilepsy when the hippocampus is not invaded by Grade II gliomas. Here, the authors compared the epileptological outcomes and return to work in 2 groups of patients who underwent surgery with or without hippocampectomy for paralimbic Grade II gliomas eliciting intractable epilepsy despite no tumoral involvement of the hippocampus.

Methods
Surgery was performed in 15 consecutive patients who were unable to work (median Karnofsky Performance Scale [KPS] Score 70) because of refractory epilepsy due to paralimbic Grade II gliomas that were not invading the hippocampus. In Group A (8 patients), the hippocampus was preserved. In Group B (7 patients), glioma removal was associated with hippocampectomy.

Results
No patient died or suffered a permanent deficit after surgery. Postoperatively, in Group A, no patients were seizure free (4 patients were in Engel Class II and 4 were in Class III). In Group B, all 7 patients were seizure free (Class I) (p = 0.02). Only 62.5% of patients returned to work in Group A, whereas all patients are working full time in Group B. The postsurgical median KPS score was 85 in Group A, that is, not significantly improved in comparison with the preoperative score, while the postsurgical median KPS was 95 in Group B, that is, significantly improved in comparison with the preoperative score (p = 0.03).

Conclusions
The authors' data support, for the first time, the significant impact of hippocampectomy in patients with intractable epilepsy generated by a paralimbic Grade II glioma, even if it does not invade the hippocampus. Hippocampal resection allowed seizure control in all patients, with an improvement in KPS scores, since all patients resumed their social and professional activities. Thus, the authors suggest performing a resection of the nontumoral hippocampus in addition to resection of the tumor in patients with refractory epilepsy due to paralimbic Grade II gliomas.
Immunoselected STRO-3+mesenchymal precursor cells and restoration of the extracellular matrix of degenerate intervertebral discs
Authors: Ghosh Peter , Moore Robert , Vernon-Roberts Barrie , Goldschlager Tony , Pascoe Diane , Zannettino Andrew , Gronthos Stan , Itescu Silviu 
Published: March 2012

ObjectChronic low-back pain of discal origin is linked strongly to disc degeneration. Current nonsurgical treatments are palliative and fail to restore the disc extracellular matrix. In this study the authors examined the capacity of ovine mesenchymal precursor cells (MPCs) to restore the extracellular matrix of degenerate discs in an ovine model.MethodsThree adjacent lumbar discs of 24 adult male sheep were injected intradiscally with chondroitinase-ABC (cABC) to initiate disc degeneration. The remaining lumbar discs were used as normal controls. Three months after cABC injection, the L3–4 discs of all animals were injected with either a high dose (4 × 106cells, in 12 sheep) or low dose (0.5 × 106cells, in 12 sheep) of MPCs suspended in hyaluronic acid (HA). The adjacent L4–5 degenerate discs remained untreated; the L5–6 discs were injected with HA only. The animals were euthanized at 3 or 6 months after MPC injections (6 sheep from each group at each time point), and histological sections of the lumbar discs were prepared. Radiographs and MR images were obtained prior to cABC injection (baseline), 3 months after cABC injection (pretreatment), and just prior to necropsy (posttreatment).ResultsInjection of cABC decreased the disc height index (DHI) of target discs by 45%–50%, confirming degeneration. Some recovery in DHI was observed 6 months after treatment in all cABC-injected discs, but the DHI increased to within baseline control values only in the MPC-injected discs. This improvement was accompanied by a reduction in MRI degeneration scores. The histopathology scores observed at 3 months posttreatment for the high-dose MPC–injected discs and at 6 months posttreatment for the low-dose MPC–injected discs were significantly different from those of the noninjected and HA-injected discs (p <0.001) but not from the control disc scores.ConclusionsOn the basis of the findings of this study, the authors conclude that the injection of MPCs into degenerate intervertebral discs can contribute to the regeneration of a new extracellular matrix.
Endoscopic balloon dilation as an adjunct to extended endoscopic approaches to the skull base
Authors: Bedrosian Jeffrey C. , Garcia-Navarro Victor , McCoul Edward D. , Anand Vijay K. , Schwartz Theodore H. 
Published: March 2012

Cholesterol granulomas (CGs) are benign, expanding cystic lesions surrounded by a thick fibrous capsule and filled with fluid, formed by the degradation of blood elements. The goal of surgery is to open the granuloma widely, creating a well-drained cavity. The endonasal endoscopic approach for this extradural lesion is a minimal access method for surgical removal or fenestration. The role of balloon dilation in creating a wide fenestration has not been previously described.
The authors describe a patient with a recurrent petrous apex CG who underwent an endoscopic, endonasal, transmaxillary transpterygoid approach to the petrous apex. A balloon sinuplasty catheter was used to dilate the surgical fenestration to maintain continued patency.
The authors report on their first experience using balloon dilation combined with endoscopic drainage of the petrous apex. The excellent surgical outcome of this minimally invasive technique holds promise for future endonasal approaches to the middle cranial fossa.
Panacea or problem: flow diverters in the treatment of symptomatic large or giant fusiform vertebrobasilar aneurysms
Authors: Siddiqui Adnan H. , Abla Adib A. , Kan Peter , Dumont Travis M. , Jahshan Shady , Britz Gavin W. , Hopkins L. Nelson , Levy Elad I. 
Published: March 2012

Object
The use of flow-diverting stents has gained momentum as a curative approach in the treatment of complex proximal anterior circulation intracranial aneurysms. There have been some reported attempts of treating formidable lesions in the posterior circulation. Posterior circulation giant fusiform aneurysms have a particularly aggressive natural history. To date, no one approach has been shown to be comprehensively effective or low risk. The authors report the initial results, including the significant morbidity and mortality encountered, with flow diversion in the treatment of large or giant fusiform vertebrobasilar aneurysms at Millard Fillmore Gates Circle Hospital.

Methods
The authors retrospectively reviewed their prospectively collected endovascular database to identify patients with intracranial aneurysms who underwent treatment with flow-diverting devices and determined that 7 patients had presented with symptomatic large or giant fusiform vertebrobasilar aneurysms. The outcomes of these patients, based on the modified Rankin Scale (mRS), were tabulated, as were the complications experienced.

Results
Among the 7 patients, Pipeline devices were placed in 6 patients and Silk devices in 1 patient. At the last follow-up evaluation, 4 patients had died (mRS score of 6), all of whom were treated with the Pipeline device. The other 3 patients had mRS scores of 5 (severe disability), 1, and 0. The deaths included posttreatment aneurysm ruptures in 2 patients and lack of improvement in neurological status related to presenting brainstem infarcts and subsequent withdrawal of care in the other 2 patients.

Conclusions
Whether flow diversion will be an effective strategy for treatment of large or giant fusiform vertebrobasilar aneurysms remains to be seen. The authors' initial experience suggests substantial morbidity and mortality associated with the treatment and with the natural history. As outcomes data slowly become available for patients receiving these devices for fusiform posterior circulation aneurysms, practitioners should use these devices judiciously.