bluuebunny/crossref_metadata_2025_split huggingface dataset:
Smectite Formation in Submarine Hydrothermal Sediments: Samples from the HMS Challenger Expedition (1872–1876)
Authors: Cuadros Javier , Dekov Vesselin M. , Arroyo Xabier , Nieto Fernando 
Published: July 2011

AbstractClay processes, mineral reactions, and element budgets in oceans continue to be important topics for scientific investigation, particularly with respect to understanding better the roles of chemistry, formation mechanism, and input from hydrothermal fluids, seawater, and non-hydrothermal mineral phases.To that end, the present study was undertaken.Thre e samples of submarine metalliferous sediments of hydrothermal origin were studied to investigate the formation of smectite, usually Fe-rich, which takes place in such environments.The samples are from the historical collection returned by the British HMS Challenger expedition (1872–1876) and kept at the Natural History Museum in London.The samples were collected from the vicinity of the Pacific–Antarctic Ridge and the Chile Ridge.The samples were analyzed by means of X-ray diffraction (XRD), chemical analysis, scanning electron microscopyenergy dispersive X-ray spectroscopy (SEM-EDX), infrared (IR), and transmission electron microscopyanalytical electron microscopy (TEM-AEM).After removal of biogenic calcite the samples appeared to consist mainly of two low-crystallinity phases mixed intimately: Fe/Mn (oxyhydr)oxides and a Si-Al-Mg- Fe phase of similar chemical characteristics to smectite and with variable proportions of the above elements, as indicated by XRD, IR, and SEM-EDX.In particular, analysis by XRD revealed the presence of highly disordered δ-MnO2.The TEM-AEM analysis showed that Fe/MnOOH particles have Fe/Mn ratios in the range 25–0.2 and textures changing from granular to veil-like as the proportion ofMn increased. The smectite-like material has the morphology and chemistry of smectite, as well as 10–15 Å lattice fringes. Selected area electron diffraction (SAED) patterns indicated a very poorly crystalline material: in some cases distances between diffraction rings corresponded to d values of smectite.The smectite composition indicated a main Fe-rich dioctahedral component with a substantialMg-rich trioctahedral component (total octahedral occupancy between 2.02 and 2.51 atoms per O10[OH]2). The (proto-) smectite is interpreted to have formed within the metalliferous sediment, as a slow reaction between Fe/MnOOH, seawater (providing Mg), detrital silicates from the continent (providing Si and Al), and X-ray amorphous silica of hydrothermal origin that adsorbed on Fe/MnOOH phases and deposited with them.This material is possibly in the process of maturation into well crystallized smectite.
Quantification of 1α,25-Dihydroxy Vitamin D by Immunoextraction and Liquid Chromatography–Tandem Mass Spectrometry
Authors: Strathmann Frederick G , Laha Thomas J , Hoofnagle Andrew N 
Published: July 2011

BACKGROUND
1α,25-dihydroxy vitamin D [1,25(OH)2D] is the active metabolite of vitamin D. Antibody-based detection methods lack specificity, but when combined with isotope dilution/ultra-performance liquid chromatography (UPLC)–tandem mass spectrometry, immunoextraction provides an attractive method for 1,25(OH)2D. We developed a method for simultaneous quantification of 1,25(OH)2D2 and 1,25(OH)2D3 with a 4.6-min instrument cycle time. Results are available 36 h after sample preparation begins.

METHODS
Sample preparation consisted of protein precipitation, immunoextraction with solid-phase anti-1,25(OH)2D antibody, and derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione. Analytes were resolved using reversed-phase UPLC and quantified using positive ion electrospray ionization–tandem mass spectrometry. We used hexadeuterated 1,25(OH)2D3 and 1,25(OH)2D2 as internal standards and performed method comparisons against the DiaSorin RIA and an LC-MS/MS method available at a reference laboratory.

RESULTS
1,25(OH)2D3 intraassay and interassay imprecision was 5.6% and 8.0% (120 pmol/L) and 8.7% and 13% (48 pmol/L). Limits of detection and quantification were 1.5 pmol/L and 3.0 pmol/L, respectively. 1,25(OH)2D2 intraassay and interassay imprecision was 8.7% and 11% (186 pmol/L) and 11% and 13% (58 pmol/L). Limits of detection and quantification were both 1.5 pmol/L. Comparison with RIA had a proportional bias of 0.75, constant bias of −4.1, and Pearson correlation (r2) of 0.31. Comparison with a reference LC-MS/MS assay had a proportional bias of 0.89, constant bias of 3.7, and r2 of 0.88.

CONCLUSIONS
Protein precipitation with antibody-based extraction is effective for sample preparation before LC-MS/MS analysis of derivatized 1,25(OH)2D. This method appears to have improved specificity over a clinically used RIA with low imprecision and limits of detection.
Laterality and Cognitive Performance in Mental Retardation
Authors: Buono Serafino , Di Nuovo Santo 
Published: July 2011

Studies on laterality have not supported the hypothesis that well-lateralized people do better on cognitive tasks than those with ‘mixed’ or uncertain laterality. This developmental characteristic appears to be not significantly linked with specific intellectual disabilities.This study was aimed at testing relationships between laterality and cognitive performance in mental retardation. In this population, indeed, previous invesigators have reported higher incidence of nonright laterality than in nonretarded persons, particularly among males and with reference to handedness.Sample and method. We studied the incidence of different forms of laterality (eye, hand, ear, and foot modalities) in a sample of 202 persons with mild and moderate mental retardation and borderline intellectual functioning, with and without neurological impairment, aged 7 – 79 years.We used 12 laterality tasks assessing, through direct observation, four modalities (hand, eye, ear, and foot preference), as suggested by Coren (1993). The laterality score was obtained using the formula: [(total Right - total Left) / (total Right + total Left)] x 100. The scores ranged from +100 (full right lateralization) to -100 (full left lateralization). The handedness score was computed using the same formula, but taking into account only the 4 tasks regarding hand preference. Lateralization was determined for each subject using a score 50 in the two opposite directions as a cutoff point.Results. Our data, considering the overall laterality, confirmed the hypothesis of reduced right prevalence (near 50% in both sexes), but did not confirm the hypothesis of a larger proportion of left lateralized subjects than in normal ones. Instead, if we refer to handedness only, the percentage of left-handed subjects is very high, almost one fifth in males, almost one tenth in females. A significant difference by gender was found in handedness across life-span. No significant differences were found regarding the level of impairment, either for overall laterality or for handedness.Correlations between lateralization scores and performances in cognitive tests, such as Wechsler Intelligence Scales (single subtests were also taken into account), Raven’s Progressive Matrices, and the Bender Visual-motor Gestalt Test, were computed. Results show significant relations between the degree of right sidedness and some cognitive performances, but these relations are differentiated for overall laterality and hand prevalence, and they are mediated by gender and severity of mental retardation.The results are useful for enhancing theoretical comprehension of the relations between laterality and cognitive processes.
The Process of Experiencing Mediated Learning as a Result of Peer Collaboration Between Young Adults With Severe Learning Difficulties
Authors: Kaufman Ruth 
Published: July 2011

Mediated learning is an interpersonal experience in which the mediator’s role is to develop in the mediatee functions essential for learning. The mediator focuses on the mediatee while identifying, analyzing, formulating, and solving problems related to everyday life and formal education frameworks. This study was focused upon the mediators, their experience in mediated learning, and the development of mediational abilities and cognitive functions as a result of social goals.Mediation was carried out in pairs and in a group format. The group was composed of low-functioning young adults suffering from severe learning problems. They acted in pairs, using a peer mediating activity, and also worked in the group to replicate their actions as well as to study the theory of mediated learning, its procedure, and its activities. The tasks were taken from Feuerstein’s cognitive intervention program, Instrumental Enrichment.Such a framework allowed me to identify and capture different aspects of students’ cognitive functioning as well as their inter- and intrapersonal mediation. Each student had to play different roles, sometimes acting as mediator to another member of the group, and thus focusing on his/her difficulties and needs, and at other times being a mediatee and receiving mediation from another group member. In addition, each student participated in the whole group activity reflecting upon, analyzing, and evaluating his/her own and his/her peer’s actions as well as those of others in the group. All this promoted strong experience in mediated learning, in different distances and modalities. Three different instruments were developed as a means of data collection and analysis: the mediation circular profile, the structural hierarchy of deficient cognitive functions map, and the process analysis flow chart.The study unfolded as a microdevelopmental process with students starting at a very low level of cognitive functioning and mediational ability and gradually progressing toward quite sophisticated methods of interaction, mediation, and problem solving. In the course of such microevolution, each group member developed his/her own position and role within the group and in the group activities.The findings support the theory of Structural Cognitive Modifiability while showing that even low-functioning people, who usually play the role of mediatee, can be mediators. By mediating to other people, they improve their own cognitive functioning, abstract level of thinking, and social and communication skills.
Prospective, Randomized, Multi-Center Feasibility Trial of rhPDGF-BB versus Autologous Bone Graft in a Foot and Ankle Fusion Model
Authors: DiGiovanni Christopher W. , Baumhauer Judith , Lin Sheldon S. , Berberian Wayne S. , Flemister Adolph S. , Enna Matthew J. , Evangelista Peter , Newman June 
Published: July 2011

Background: The increased morbidity and surgical time associated with harvesting autologous bone graft (ABG) have encouraged surgeons to develop synthetic orthobiologic alternatives. The recombinant form of platelet-derived growth factor (rhPDGF-BB), an angiogenic, mitogenic, and chemotactic cytokine, has been shown to significantly enhance bone formation in human periodontal osseous defects when combined with a tricalcium phosphate carrier (β-TCP). The purpose of this prospective, controlled, randomized, multi-center feasibility clinical trial was to compare the safety and efficacy of this biosynthetic bone graft substitute (Augment™ Bone Graft) to ABG during ankle and hindfoot fusion. Materials and Methods: Twenty adult subjects requiring ankle or hindfoot fusion from three U.S. centers were enrolled and randomized in a 2:1 ratio to receive Augment™ or ABG, respectively. Surgical approach and fixation techniques were standardized, and minimum followup was 9 months. The primary endpoint was radiographic osseous union, evaluated by a blinded independent radiologist. Secondary endpoints included assessment of clinical success, union rate by serial computed tomography (CT) examination, time to full weightbearing, AOFAS Ankle-Hindfoot Score (AOFAS), Foot Function Index (FFI), Short Form-12 (SF-12), and Visual Analog pain assessment Scale (Pain VAS). Results: At 36 weeks, 77% (10/13) of the Augment™ and 50% (3/6) of the ABG patients were fused based on radiographic criteria. There were two nonunions in the Augment™ group (9%, 2/14). Healing rates based on 12 week CT scanning (50% osseous bridging) were 69% (9/13) in the Augment™ and 60% (3/5) in the ABG groups, respectively. All functional outcome measures (FFI, AOFAS, SF-12), as well as the VAS pain scores, improved in both groups over time. Surgical procedure times lasted an average 26 minutes longer for the ABG as compared to the Augment™ populations. There were no device related serious adverse events in this study. Conclusion: Based on the available data, the rate of radiographic union, time to full weightbearing, and outcomes scores between the Augment™ and ABG subjects appear comparable. Augment™ may represent a safe and efficacious treatment alternative to ABG during foot and ankle arthrodesis. Level of Evidence:
Outcomes following Midfoot Arthrodesis for Primary Arthritis
Authors: Nemec Scott A. , Habbu Rohan A. , Anderson John G. , Bohay Donald R. 
Published: July 2011

Background: Primary midfoot arthritis is a disabling painful condition of the foot. The aim of the study was to assess the functional outcomes following midfoot arthrodesis for primary midfoot arthritis. Materials and Methods: Between 2000 and 2006, 95 patients (104 feet) underwent midfoot arthrodesis for primary midfoot arthritis. Midfoot collapse, if present, was corrected at the time of arthrodesis. Mean age at surgery was 62 years. Gastrocnemius contracture was seen in 81 (78%) feet and was treated with a recession. Radiographs were reviewed for correction of deformity. Complications and reoperations were noted. Outcome evaluation included pain, American Orthopaedic Foot Ankle Society (AOFAS) midfoot score and patient satisfaction. Outcomes were available in 68 patients (74 feet) with mean followup of 56 (range, 24 to 102) months. Results: We achieved union in 96 out of 104 feet (92%). There was one delayed union and eight nonunions. Major complications (4/104, 4%) included three deep infections and one chronic regional pain syndrome. Reoperations were required in 11 feet in addition to 26 symptomatic hardware removals. Radiographs showed a significant improvement in the talo-first metatarsal angle and medial cuneiform height. Pain improved from preoperative mean of 7 ± 2 to postoperative mean of 2 ± 2. AOFAS score improved from preoperative mean of 32 (range, 25 to 43) to postoperative mean of 79 (range, 65 to 90). Ninety percent of patients were satisfied with the final result. Conclusion: Primary or degenerative arthritis of the midfoot with refractory symptoms was treated with midfoot arthrodesis with good results and a low incidence of nonunion. Level of Evidence: IV, Retrospective Case Series
Noninsertional Achilles Tendinopathy Treated with Gastrocnemius Lengthening
Authors: Duthon Victoria B. , Lubbeke Anne , Duc Sylvain R. , Stern Richard , Assal Mathieu 
Published: July 2011

Background: Surgery is frequently considered an option for refractory, symptomatic noninsertional Achilles tendinopathy. Gastrocnemius equinus can result in mechanical overload of the Achilles tendon and may be a factor in its etiology. Our hypothesis was that reducing load transmission to the Achilles tendon by gastrocnemius lengthening (Strayer procedure) may be an effective treatment. Materials and Methods: A prospective case series of all patients with a minimum 1-year symptomatic nonin-sertional Achilles tendinopathy who underwent gastrocnemius lengthening was evaluated before surgery, and at 1 and 2 years after surgery. There were 14 patients (17 tendons). Results: One year after surgery, the median American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score was 100 points, as compared to 71 points preoperatively ( p< 0.001). The median total Foot Function Index (FFI) decreased significantly from 39 to 12 points at 1 year ( p< 0.001) and remained stable (12 points) at 2 years. An electronic goniometer recorded a mean gain in ankle dorsiflexion of 13 degrees. At 1 year after surgery the MRI in all eight patients (ten tendons) with a preoperative MRI demonstrated a decrease in signal hyperintensity and tendon size, signifying an improvement of the tendinopathy. At 2 years after surgery, patient satisfaction assessment revealed that all but one patient was satisfied with the result and 11 of the 14 (79%) patients were able to resume their previous sporting activities. There were no complications. Conclusion: Gastrocne-mius lengthening was an effective treatment for chronic Achilles noninsertional tendinopathy. Two-year results show good to excellent clinical outcome. Level of Evidence: Level IV, Prospective Case Series
Radiographic Analysis of Wedge Allograft Correction of Angular Malalignment in Ankle Fusion
Authors: Kleiber Brian D. , Klein Sandra E. , McCormick Jeremy J. , Johnson Jeffrey E. 
Published: July 2011

Background: Patients undergoing ankle arthrodesis often have coronal or sagittal plane malalignment. Correction of this deformity can be technically challenging. This retrospective review examines the use of an augmented interposition wedge allograft for deformity correction in ankle arthrodesis. Materials and Methods: Nineteen patients underwent open ankle arthrodesis with interposition allograft at our institution since 2003. Sixteen patients had isolated ankle fusions and three patients had ankle fusions as part of a tibiotalocalcaneal fusion. A wedge of frozen tricortical iliac crest or femoral head allograft was cut to appropriate size and shape to correct angular deformity with an average maximum graft width of 9.5 mm. Fixation of the arthrodesis was with either a cannulated screw and plate construct or a lateral blade plate. Radiographs were reviewed to assess preoperative, initial postoperative and final alignment at the time of solid fusion. Fusion was assessed on plain radiographs by visualization of bridging bony trabeculae. Results: Seventeen of 19 patients (89%) obtained fusion at an average of 14.9 wks. Eleven ankles had preoperative tibiotalar valgus deformity with an average coronal alignment of 98.8 degrees and sagittal alignment of 110.5 degrees. Final coronal alignment was 90.9 degrees and sagittal alignment was 107.7 degrees. Eight ankles had varus deformity with an average coronal alignment of 77.4 degrees and sagittal alignment of 101.9 degrees. Final coronal alignment was 89.4 degrees and sagittal alignment was 107.4 degrees. Conclusion: The tibiotalar joint fusion rate in this series compares favorably to historically published data for standard ankle fusion. Interposition allograft was an effective method for deformity correction in difficult ankle arthrodeses. Level of Evidence: IV, Retrospective Case Series
Surgeon Practices regarding Operative Treatment of Posterior Malleolus Fractures
Authors: Gardner Michael J. , Streubel Philipp N. , McCormick Jeremy J. , Klein Sandra E. , Johnson Jeffrey E. , Ricci William M. 
Published: July 2011

Background: Operative indications for surgical treatment of posterior malleolar fractures associated with fractures of the distal fibula and tibia are not currently well defined. The purpose of the present study was to determine the current practice among orthopaedic surgeons regarding the management of posterior malleolus fractures. Materials and Methods: Web-based questionnaires were emailed to members of the Orthopaedic Trauma Association (OTA) and American Orthopaedic Foot and Ankle Society (AOFAS). Requested information included demographics and treatment preferences for five clinical scenarios with different fracture characteristics. Four hundred one respondents completed the survey (20% response rate). Ninety eight (24%) subjects had received specialty training in orthopaedic trauma, 199 (50%) in foot and ankle (F&A) surgery and six (2%) in both orthopaedic trauma and F&A surgery. Ninety five (24%) had either no or other specialty training. Results: The most frequently reported indication for fixation was not based on a fragment size threshold, but rather was “depends on stability and other factors” (56%). Trauma surgeons, those with less than 10 years experience, and those who treated more than five ankles fractures per month were significantly more likely to use factors other than size for indications ( p =0.026,<0.01, and <0.01, respectively). Despite this general response, fragment size still affected treatment decisions. A fragment comprising 50% of the articular surface was indicated for fixation by 97% of respondents, while a size of 10% would be treated by only 9% of respondents. For a posterior fragment with 20% articular involvement and a small free osteochondral fragment, fixation was deemed necessary by 44% of respondents. There were no differences in fellowship training, years of experience in practice, or ankle fracture volume per month in these three situations. A larger proportion of trauma trained surgeons considered fixation necessary compared to F&A trained surgeons in this case ( p=0.028). When posterior malleolus fixation was indicated for a large fragment, direct open reduction using the flexor hallucis longus –peroneal tendon interval was the most commonly selected approach in all cases. Trauma-trained surgeons were significantly more likely to choose antiglide plate fixation compared to screw-only fixation ( p <0.05). Conclusion: In this survey study of trauma and F&A surgeons, significant variation existed regarding most aspects of posterior malleolar ankle fracture treatment. Most notably, factors other than fragment size most impacted surgical indications. Newer techniques such as direct exposure and plating of the posterior malleolus are chosen more frequently than traditional techniques of indirect reduction and percutaneous screw fixation. Level of Evidence: IV, Cross-sectional Survey Study
Corticosteroid Injections in the Treatment of Foot & Ankle Disorders: An AOFAS Survey
Authors: Johnson Jeffrey E. , Klein Sandra E. , Putnam Ryan M. 
Published: July 2011

Background: Evidence-based guidelines for the use of injectable corticosteroids are lacking, and the true incidence of complications is unknown. Materials and Methods: The 2007–2008 AOFAS membership (969 members) was electronically queried to identify corticosteroid injection practices for certain clinical entities and rates of complications. One hundred ninety-seven surveys were returned. Eleven clinical diagnoses were evaluated for number of injections per year per respondent, rate of injection, plans to change injection pattern, and use of immobilization. Thirteen possible complications were analyzed for observed frequencies and total number of complications. Results: Those in practice less than 5 years showed the lowest rate of injections at 14.1 per month, which increased to 26.1 for those in practice 6 to 10 years. An overall average of 20.6 injections per month per clinician was reported. Injections for midsubstance Achilles tendinopathy was largely avoided as demonstrated by a 98% no-inject rate. Insertional Achilles tendonitis was similar, albeit lower with an 88% no-inject rate. Non-Achilles tendonitis showed a varied response for injections. Posterior tibial tendonitis was injected 26% of the time, whereas peroneal tendonitis was injected 54% of the time. Complications including skin depigmentation were observed most frequently (5.1%), followed by atrophy (4%), flare reaction (3.5%), MTPJ dislocation (2.7%), plantar fascia rupture (1.5%), and heel pad atrophy (1.4%). Conclusion: Despite many case reports of complications, our survey indicates that the incidence of complications was perceived to be low and generally related to the injection site (skin depigmentation, atrophy, flare reaction).